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1/*
2 * Copyright (c) 2003-2006, Cluster File Systems, Inc, info@clusterfs.com
3 * Written by Alex Tomas <alex@clusterfs.com>
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License version 2 as
7 * published by the Free Software Foundation.
8 *
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write to the Free Software
16 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-
17 */
18
19
20/*
21 * mballoc.c contains the multiblocks allocation routines
22 */
23
24#include "ext4_jbd2.h"
25#include "mballoc.h"
26#include <linux/log2.h>
27#include <linux/module.h>
28#include <linux/slab.h>
29#include <linux/backing-dev.h>
30#include <trace/events/ext4.h>
31
32#ifdef CONFIG_EXT4_DEBUG
33ushort ext4_mballoc_debug __read_mostly;
34
35module_param_named(mballoc_debug, ext4_mballoc_debug, ushort, 0644);
36MODULE_PARM_DESC(mballoc_debug, "Debugging level for ext4's mballoc");
37#endif
38
39/*
40 * MUSTDO:
41 * - test ext4_ext_search_left() and ext4_ext_search_right()
42 * - search for metadata in few groups
43 *
44 * TODO v4:
45 * - normalization should take into account whether file is still open
46 * - discard preallocations if no free space left (policy?)
47 * - don't normalize tails
48 * - quota
49 * - reservation for superuser
50 *
51 * TODO v3:
52 * - bitmap read-ahead (proposed by Oleg Drokin aka green)
53 * - track min/max extents in each group for better group selection
54 * - mb_mark_used() may allocate chunk right after splitting buddy
55 * - tree of groups sorted by number of free blocks
56 * - error handling
57 */
58
59/*
60 * The allocation request involve request for multiple number of blocks
61 * near to the goal(block) value specified.
62 *
63 * During initialization phase of the allocator we decide to use the
64 * group preallocation or inode preallocation depending on the size of
65 * the file. The size of the file could be the resulting file size we
66 * would have after allocation, or the current file size, which ever
67 * is larger. If the size is less than sbi->s_mb_stream_request we
68 * select to use the group preallocation. The default value of
69 * s_mb_stream_request is 16 blocks. This can also be tuned via
70 * /sys/fs/ext4/<partition>/mb_stream_req. The value is represented in
71 * terms of number of blocks.
72 *
73 * The main motivation for having small file use group preallocation is to
74 * ensure that we have small files closer together on the disk.
75 *
76 * First stage the allocator looks at the inode prealloc list,
77 * ext4_inode_info->i_prealloc_list, which contains list of prealloc
78 * spaces for this particular inode. The inode prealloc space is
79 * represented as:
80 *
81 * pa_lstart -> the logical start block for this prealloc space
82 * pa_pstart -> the physical start block for this prealloc space
83 * pa_len -> length for this prealloc space (in clusters)
84 * pa_free -> free space available in this prealloc space (in clusters)
85 *
86 * The inode preallocation space is used looking at the _logical_ start
87 * block. If only the logical file block falls within the range of prealloc
88 * space we will consume the particular prealloc space. This makes sure that
89 * we have contiguous physical blocks representing the file blocks
90 *
91 * The important thing to be noted in case of inode prealloc space is that
92 * we don't modify the values associated to inode prealloc space except
93 * pa_free.
94 *
95 * If we are not able to find blocks in the inode prealloc space and if we
96 * have the group allocation flag set then we look at the locality group
97 * prealloc space. These are per CPU prealloc list represented as
98 *
99 * ext4_sb_info.s_locality_groups[smp_processor_id()]
100 *
101 * The reason for having a per cpu locality group is to reduce the contention
102 * between CPUs. It is possible to get scheduled at this point.
103 *
104 * The locality group prealloc space is used looking at whether we have
105 * enough free space (pa_free) within the prealloc space.
106 *
107 * If we can't allocate blocks via inode prealloc or/and locality group
108 * prealloc then we look at the buddy cache. The buddy cache is represented
109 * by ext4_sb_info.s_buddy_cache (struct inode) whose file offset gets
110 * mapped to the buddy and bitmap information regarding different
111 * groups. The buddy information is attached to buddy cache inode so that
112 * we can access them through the page cache. The information regarding
113 * each group is loaded via ext4_mb_load_buddy. The information involve
114 * block bitmap and buddy information. The information are stored in the
115 * inode as:
116 *
117 * { page }
118 * [ group 0 bitmap][ group 0 buddy] [group 1][ group 1]...
119 *
120 *
121 * one block each for bitmap and buddy information. So for each group we
122 * take up 2 blocks. A page can contain blocks_per_page (PAGE_SIZE /
123 * blocksize) blocks. So it can have information regarding groups_per_page
124 * which is blocks_per_page/2
125 *
126 * The buddy cache inode is not stored on disk. The inode is thrown
127 * away when the filesystem is unmounted.
128 *
129 * We look for count number of blocks in the buddy cache. If we were able
130 * to locate that many free blocks we return with additional information
131 * regarding rest of the contiguous physical block available
132 *
133 * Before allocating blocks via buddy cache we normalize the request
134 * blocks. This ensure we ask for more blocks that we needed. The extra
135 * blocks that we get after allocation is added to the respective prealloc
136 * list. In case of inode preallocation we follow a list of heuristics
137 * based on file size. This can be found in ext4_mb_normalize_request. If
138 * we are doing a group prealloc we try to normalize the request to
139 * sbi->s_mb_group_prealloc. The default value of s_mb_group_prealloc is
140 * dependent on the cluster size; for non-bigalloc file systems, it is
141 * 512 blocks. This can be tuned via
142 * /sys/fs/ext4/<partition>/mb_group_prealloc. The value is represented in
143 * terms of number of blocks. If we have mounted the file system with -O
144 * stripe=<value> option the group prealloc request is normalized to the
145 * the smallest multiple of the stripe value (sbi->s_stripe) which is
146 * greater than the default mb_group_prealloc.
147 *
148 * The regular allocator (using the buddy cache) supports a few tunables.
149 *
150 * /sys/fs/ext4/<partition>/mb_min_to_scan
151 * /sys/fs/ext4/<partition>/mb_max_to_scan
152 * /sys/fs/ext4/<partition>/mb_order2_req
153 *
154 * The regular allocator uses buddy scan only if the request len is power of
155 * 2 blocks and the order of allocation is >= sbi->s_mb_order2_reqs. The
156 * value of s_mb_order2_reqs can be tuned via
157 * /sys/fs/ext4/<partition>/mb_order2_req. If the request len is equal to
158 * stripe size (sbi->s_stripe), we try to search for contiguous block in
159 * stripe size. This should result in better allocation on RAID setups. If
160 * not, we search in the specific group using bitmap for best extents. The
161 * tunable min_to_scan and max_to_scan control the behaviour here.
162 * min_to_scan indicate how long the mballoc __must__ look for a best
163 * extent and max_to_scan indicates how long the mballoc __can__ look for a
164 * best extent in the found extents. Searching for the blocks starts with
165 * the group specified as the goal value in allocation context via
166 * ac_g_ex. Each group is first checked based on the criteria whether it
167 * can be used for allocation. ext4_mb_good_group explains how the groups are
168 * checked.
169 *
170 * Both the prealloc space are getting populated as above. So for the first
171 * request we will hit the buddy cache which will result in this prealloc
172 * space getting filled. The prealloc space is then later used for the
173 * subsequent request.
174 */
175
176/*
177 * mballoc operates on the following data:
178 * - on-disk bitmap
179 * - in-core buddy (actually includes buddy and bitmap)
180 * - preallocation descriptors (PAs)
181 *
182 * there are two types of preallocations:
183 * - inode
184 * assiged to specific inode and can be used for this inode only.
185 * it describes part of inode's space preallocated to specific
186 * physical blocks. any block from that preallocated can be used
187 * independent. the descriptor just tracks number of blocks left
188 * unused. so, before taking some block from descriptor, one must
189 * make sure corresponded logical block isn't allocated yet. this
190 * also means that freeing any block within descriptor's range
191 * must discard all preallocated blocks.
192 * - locality group
193 * assigned to specific locality group which does not translate to
194 * permanent set of inodes: inode can join and leave group. space
195 * from this type of preallocation can be used for any inode. thus
196 * it's consumed from the beginning to the end.
197 *
198 * relation between them can be expressed as:
199 * in-core buddy = on-disk bitmap + preallocation descriptors
200 *
201 * this mean blocks mballoc considers used are:
202 * - allocated blocks (persistent)
203 * - preallocated blocks (non-persistent)
204 *
205 * consistency in mballoc world means that at any time a block is either
206 * free or used in ALL structures. notice: "any time" should not be read
207 * literally -- time is discrete and delimited by locks.
208 *
209 * to keep it simple, we don't use block numbers, instead we count number of
210 * blocks: how many blocks marked used/free in on-disk bitmap, buddy and PA.
211 *
212 * all operations can be expressed as:
213 * - init buddy: buddy = on-disk + PAs
214 * - new PA: buddy += N; PA = N
215 * - use inode PA: on-disk += N; PA -= N
216 * - discard inode PA buddy -= on-disk - PA; PA = 0
217 * - use locality group PA on-disk += N; PA -= N
218 * - discard locality group PA buddy -= PA; PA = 0
219 * note: 'buddy -= on-disk - PA' is used to show that on-disk bitmap
220 * is used in real operation because we can't know actual used
221 * bits from PA, only from on-disk bitmap
222 *
223 * if we follow this strict logic, then all operations above should be atomic.
224 * given some of them can block, we'd have to use something like semaphores
225 * killing performance on high-end SMP hardware. let's try to relax it using
226 * the following knowledge:
227 * 1) if buddy is referenced, it's already initialized
228 * 2) while block is used in buddy and the buddy is referenced,
229 * nobody can re-allocate that block
230 * 3) we work on bitmaps and '+' actually means 'set bits'. if on-disk has
231 * bit set and PA claims same block, it's OK. IOW, one can set bit in
232 * on-disk bitmap if buddy has same bit set or/and PA covers corresponded
233 * block
234 *
235 * so, now we're building a concurrency table:
236 * - init buddy vs.
237 * - new PA
238 * blocks for PA are allocated in the buddy, buddy must be referenced
239 * until PA is linked to allocation group to avoid concurrent buddy init
240 * - use inode PA
241 * we need to make sure that either on-disk bitmap or PA has uptodate data
242 * given (3) we care that PA-=N operation doesn't interfere with init
243 * - discard inode PA
244 * the simplest way would be to have buddy initialized by the discard
245 * - use locality group PA
246 * again PA-=N must be serialized with init
247 * - discard locality group PA
248 * the simplest way would be to have buddy initialized by the discard
249 * - new PA vs.
250 * - use inode PA
251 * i_data_sem serializes them
252 * - discard inode PA
253 * discard process must wait until PA isn't used by another process
254 * - use locality group PA
255 * some mutex should serialize them
256 * - discard locality group PA
257 * discard process must wait until PA isn't used by another process
258 * - use inode PA
259 * - use inode PA
260 * i_data_sem or another mutex should serializes them
261 * - discard inode PA
262 * discard process must wait until PA isn't used by another process
263 * - use locality group PA
264 * nothing wrong here -- they're different PAs covering different blocks
265 * - discard locality group PA
266 * discard process must wait until PA isn't used by another process
267 *
268 * now we're ready to make few consequences:
269 * - PA is referenced and while it is no discard is possible
270 * - PA is referenced until block isn't marked in on-disk bitmap
271 * - PA changes only after on-disk bitmap
272 * - discard must not compete with init. either init is done before
273 * any discard or they're serialized somehow
274 * - buddy init as sum of on-disk bitmap and PAs is done atomically
275 *
276 * a special case when we've used PA to emptiness. no need to modify buddy
277 * in this case, but we should care about concurrent init
278 *
279 */
280
281 /*
282 * Logic in few words:
283 *
284 * - allocation:
285 * load group
286 * find blocks
287 * mark bits in on-disk bitmap
288 * release group
289 *
290 * - use preallocation:
291 * find proper PA (per-inode or group)
292 * load group
293 * mark bits in on-disk bitmap
294 * release group
295 * release PA
296 *
297 * - free:
298 * load group
299 * mark bits in on-disk bitmap
300 * release group
301 *
302 * - discard preallocations in group:
303 * mark PAs deleted
304 * move them onto local list
305 * load on-disk bitmap
306 * load group
307 * remove PA from object (inode or locality group)
308 * mark free blocks in-core
309 *
310 * - discard inode's preallocations:
311 */
312
313/*
314 * Locking rules
315 *
316 * Locks:
317 * - bitlock on a group (group)
318 * - object (inode/locality) (object)
319 * - per-pa lock (pa)
320 *
321 * Paths:
322 * - new pa
323 * object
324 * group
325 *
326 * - find and use pa:
327 * pa
328 *
329 * - release consumed pa:
330 * pa
331 * group
332 * object
333 *
334 * - generate in-core bitmap:
335 * group
336 * pa
337 *
338 * - discard all for given object (inode, locality group):
339 * object
340 * pa
341 * group
342 *
343 * - discard all for given group:
344 * group
345 * pa
346 * group
347 * object
348 *
349 */
350static struct kmem_cache *ext4_pspace_cachep;
351static struct kmem_cache *ext4_ac_cachep;
352static struct kmem_cache *ext4_free_data_cachep;
353
354/* We create slab caches for groupinfo data structures based on the
355 * superblock block size. There will be one per mounted filesystem for
356 * each unique s_blocksize_bits */
357#define NR_GRPINFO_CACHES 8
358static struct kmem_cache *ext4_groupinfo_caches[NR_GRPINFO_CACHES];
359
360static const char *ext4_groupinfo_slab_names[NR_GRPINFO_CACHES] = {
361 "ext4_groupinfo_1k", "ext4_groupinfo_2k", "ext4_groupinfo_4k",
362 "ext4_groupinfo_8k", "ext4_groupinfo_16k", "ext4_groupinfo_32k",
363 "ext4_groupinfo_64k", "ext4_groupinfo_128k"
364};
365
366static void ext4_mb_generate_from_pa(struct super_block *sb, void *bitmap,
367 ext4_group_t group);
368static void ext4_mb_generate_from_freelist(struct super_block *sb, void *bitmap,
369 ext4_group_t group);
370static void ext4_free_data_callback(struct super_block *sb,
371 struct ext4_journal_cb_entry *jce, int rc);
372
373static inline void *mb_correct_addr_and_bit(int *bit, void *addr)
374{
375#if BITS_PER_LONG == 64
376 *bit += ((unsigned long) addr & 7UL) << 3;
377 addr = (void *) ((unsigned long) addr & ~7UL);
378#elif BITS_PER_LONG == 32
379 *bit += ((unsigned long) addr & 3UL) << 3;
380 addr = (void *) ((unsigned long) addr & ~3UL);
381#else
382#error "how many bits you are?!"
383#endif
384 return addr;
385}
386
387static inline int mb_test_bit(int bit, void *addr)
388{
389 /*
390 * ext4_test_bit on architecture like powerpc
391 * needs unsigned long aligned address
392 */
393 addr = mb_correct_addr_and_bit(&bit, addr);
394 return ext4_test_bit(bit, addr);
395}
396
397static inline void mb_set_bit(int bit, void *addr)
398{
399 addr = mb_correct_addr_and_bit(&bit, addr);
400 ext4_set_bit(bit, addr);
401}
402
403static inline void mb_clear_bit(int bit, void *addr)
404{
405 addr = mb_correct_addr_and_bit(&bit, addr);
406 ext4_clear_bit(bit, addr);
407}
408
409static inline int mb_test_and_clear_bit(int bit, void *addr)
410{
411 addr = mb_correct_addr_and_bit(&bit, addr);
412 return ext4_test_and_clear_bit(bit, addr);
413}
414
415static inline int mb_find_next_zero_bit(void *addr, int max, int start)
416{
417 int fix = 0, ret, tmpmax;
418 addr = mb_correct_addr_and_bit(&fix, addr);
419 tmpmax = max + fix;
420 start += fix;
421
422 ret = ext4_find_next_zero_bit(addr, tmpmax, start) - fix;
423 if (ret > max)
424 return max;
425 return ret;
426}
427
428static inline int mb_find_next_bit(void *addr, int max, int start)
429{
430 int fix = 0, ret, tmpmax;
431 addr = mb_correct_addr_and_bit(&fix, addr);
432 tmpmax = max + fix;
433 start += fix;
434
435 ret = ext4_find_next_bit(addr, tmpmax, start) - fix;
436 if (ret > max)
437 return max;
438 return ret;
439}
440
441static void *mb_find_buddy(struct ext4_buddy *e4b, int order, int *max)
442{
443 char *bb;
444
445 BUG_ON(e4b->bd_bitmap == e4b->bd_buddy);
446 BUG_ON(max == NULL);
447
448 if (order > e4b->bd_blkbits + 1) {
449 *max = 0;
450 return NULL;
451 }
452
453 /* at order 0 we see each particular block */
454 if (order == 0) {
455 *max = 1 << (e4b->bd_blkbits + 3);
456 return e4b->bd_bitmap;
457 }
458
459 bb = e4b->bd_buddy + EXT4_SB(e4b->bd_sb)->s_mb_offsets[order];
460 *max = EXT4_SB(e4b->bd_sb)->s_mb_maxs[order];
461
462 return bb;
463}
464
465#ifdef DOUBLE_CHECK
466static void mb_free_blocks_double(struct inode *inode, struct ext4_buddy *e4b,
467 int first, int count)
468{
469 int i;
470 struct super_block *sb = e4b->bd_sb;
471
472 if (unlikely(e4b->bd_info->bb_bitmap == NULL))
473 return;
474 assert_spin_locked(ext4_group_lock_ptr(sb, e4b->bd_group));
475 for (i = 0; i < count; i++) {
476 if (!mb_test_bit(first + i, e4b->bd_info->bb_bitmap)) {
477 ext4_fsblk_t blocknr;
478
479 blocknr = ext4_group_first_block_no(sb, e4b->bd_group);
480 blocknr += EXT4_C2B(EXT4_SB(sb), first + i);
481 ext4_grp_locked_error(sb, e4b->bd_group,
482 inode ? inode->i_ino : 0,
483 blocknr,
484 "freeing block already freed "
485 "(bit %u)",
486 first + i);
487 }
488 mb_clear_bit(first + i, e4b->bd_info->bb_bitmap);
489 }
490}
491
492static void mb_mark_used_double(struct ext4_buddy *e4b, int first, int count)
493{
494 int i;
495
496 if (unlikely(e4b->bd_info->bb_bitmap == NULL))
497 return;
498 assert_spin_locked(ext4_group_lock_ptr(e4b->bd_sb, e4b->bd_group));
499 for (i = 0; i < count; i++) {
500 BUG_ON(mb_test_bit(first + i, e4b->bd_info->bb_bitmap));
501 mb_set_bit(first + i, e4b->bd_info->bb_bitmap);
502 }
503}
504
505static void mb_cmp_bitmaps(struct ext4_buddy *e4b, void *bitmap)
506{
507 if (memcmp(e4b->bd_info->bb_bitmap, bitmap, e4b->bd_sb->s_blocksize)) {
508 unsigned char *b1, *b2;
509 int i;
510 b1 = (unsigned char *) e4b->bd_info->bb_bitmap;
511 b2 = (unsigned char *) bitmap;
512 for (i = 0; i < e4b->bd_sb->s_blocksize; i++) {
513 if (b1[i] != b2[i]) {
514 ext4_msg(e4b->bd_sb, KERN_ERR,
515 "corruption in group %u "
516 "at byte %u(%u): %x in copy != %x "
517 "on disk/prealloc",
518 e4b->bd_group, i, i * 8, b1[i], b2[i]);
519 BUG();
520 }
521 }
522 }
523}
524
525#else
526static inline void mb_free_blocks_double(struct inode *inode,
527 struct ext4_buddy *e4b, int first, int count)
528{
529 return;
530}
531static inline void mb_mark_used_double(struct ext4_buddy *e4b,
532 int first, int count)
533{
534 return;
535}
536static inline void mb_cmp_bitmaps(struct ext4_buddy *e4b, void *bitmap)
537{
538 return;
539}
540#endif
541
542#ifdef AGGRESSIVE_CHECK
543
544#define MB_CHECK_ASSERT(assert) \
545do { \
546 if (!(assert)) { \
547 printk(KERN_EMERG \
548 "Assertion failure in %s() at %s:%d: \"%s\"\n", \
549 function, file, line, # assert); \
550 BUG(); \
551 } \
552} while (0)
553
554static int __mb_check_buddy(struct ext4_buddy *e4b, char *file,
555 const char *function, int line)
556{
557 struct super_block *sb = e4b->bd_sb;
558 int order = e4b->bd_blkbits + 1;
559 int max;
560 int max2;
561 int i;
562 int j;
563 int k;
564 int count;
565 struct ext4_group_info *grp;
566 int fragments = 0;
567 int fstart;
568 struct list_head *cur;
569 void *buddy;
570 void *buddy2;
571
572 {
573 static int mb_check_counter;
574 if (mb_check_counter++ % 100 != 0)
575 return 0;
576 }
577
578 while (order > 1) {
579 buddy = mb_find_buddy(e4b, order, &max);
580 MB_CHECK_ASSERT(buddy);
581 buddy2 = mb_find_buddy(e4b, order - 1, &max2);
582 MB_CHECK_ASSERT(buddy2);
583 MB_CHECK_ASSERT(buddy != buddy2);
584 MB_CHECK_ASSERT(max * 2 == max2);
585
586 count = 0;
587 for (i = 0; i < max; i++) {
588
589 if (mb_test_bit(i, buddy)) {
590 /* only single bit in buddy2 may be 1 */
591 if (!mb_test_bit(i << 1, buddy2)) {
592 MB_CHECK_ASSERT(
593 mb_test_bit((i<<1)+1, buddy2));
594 } else if (!mb_test_bit((i << 1) + 1, buddy2)) {
595 MB_CHECK_ASSERT(
596 mb_test_bit(i << 1, buddy2));
597 }
598 continue;
599 }
600
601 /* both bits in buddy2 must be 1 */
602 MB_CHECK_ASSERT(mb_test_bit(i << 1, buddy2));
603 MB_CHECK_ASSERT(mb_test_bit((i << 1) + 1, buddy2));
604
605 for (j = 0; j < (1 << order); j++) {
606 k = (i * (1 << order)) + j;
607 MB_CHECK_ASSERT(
608 !mb_test_bit(k, e4b->bd_bitmap));
609 }
610 count++;
611 }
612 MB_CHECK_ASSERT(e4b->bd_info->bb_counters[order] == count);
613 order--;
614 }
615
616 fstart = -1;
617 buddy = mb_find_buddy(e4b, 0, &max);
618 for (i = 0; i < max; i++) {
619 if (!mb_test_bit(i, buddy)) {
620 MB_CHECK_ASSERT(i >= e4b->bd_info->bb_first_free);
621 if (fstart == -1) {
622 fragments++;
623 fstart = i;
624 }
625 continue;
626 }
627 fstart = -1;
628 /* check used bits only */
629 for (j = 0; j < e4b->bd_blkbits + 1; j++) {
630 buddy2 = mb_find_buddy(e4b, j, &max2);
631 k = i >> j;
632 MB_CHECK_ASSERT(k < max2);
633 MB_CHECK_ASSERT(mb_test_bit(k, buddy2));
634 }
635 }
636 MB_CHECK_ASSERT(!EXT4_MB_GRP_NEED_INIT(e4b->bd_info));
637 MB_CHECK_ASSERT(e4b->bd_info->bb_fragments == fragments);
638
639 grp = ext4_get_group_info(sb, e4b->bd_group);
640 list_for_each(cur, &grp->bb_prealloc_list) {
641 ext4_group_t groupnr;
642 struct ext4_prealloc_space *pa;
643 pa = list_entry(cur, struct ext4_prealloc_space, pa_group_list);
644 ext4_get_group_no_and_offset(sb, pa->pa_pstart, &groupnr, &k);
645 MB_CHECK_ASSERT(groupnr == e4b->bd_group);
646 for (i = 0; i < pa->pa_len; i++)
647 MB_CHECK_ASSERT(mb_test_bit(k + i, buddy));
648 }
649 return 0;
650}
651#undef MB_CHECK_ASSERT
652#define mb_check_buddy(e4b) __mb_check_buddy(e4b, \
653 __FILE__, __func__, __LINE__)
654#else
655#define mb_check_buddy(e4b)
656#endif
657
658/*
659 * Divide blocks started from @first with length @len into
660 * smaller chunks with power of 2 blocks.
661 * Clear the bits in bitmap which the blocks of the chunk(s) covered,
662 * then increase bb_counters[] for corresponded chunk size.
663 */
664static void ext4_mb_mark_free_simple(struct super_block *sb,
665 void *buddy, ext4_grpblk_t first, ext4_grpblk_t len,
666 struct ext4_group_info *grp)
667{
668 struct ext4_sb_info *sbi = EXT4_SB(sb);
669 ext4_grpblk_t min;
670 ext4_grpblk_t max;
671 ext4_grpblk_t chunk;
672 unsigned short border;
673
674 BUG_ON(len > EXT4_CLUSTERS_PER_GROUP(sb));
675
676 border = 2 << sb->s_blocksize_bits;
677
678 while (len > 0) {
679 /* find how many blocks can be covered since this position */
680 max = ffs(first | border) - 1;
681
682 /* find how many blocks of power 2 we need to mark */
683 min = fls(len) - 1;
684
685 if (max < min)
686 min = max;
687 chunk = 1 << min;
688
689 /* mark multiblock chunks only */
690 grp->bb_counters[min]++;
691 if (min > 0)
692 mb_clear_bit(first >> min,
693 buddy + sbi->s_mb_offsets[min]);
694
695 len -= chunk;
696 first += chunk;
697 }
698}
699
700/*
701 * Cache the order of the largest free extent we have available in this block
702 * group.
703 */
704static void
705mb_set_largest_free_order(struct super_block *sb, struct ext4_group_info *grp)
706{
707 int i;
708 int bits;
709
710 grp->bb_largest_free_order = -1; /* uninit */
711
712 bits = sb->s_blocksize_bits + 1;
713 for (i = bits; i >= 0; i--) {
714 if (grp->bb_counters[i] > 0) {
715 grp->bb_largest_free_order = i;
716 break;
717 }
718 }
719}
720
721static noinline_for_stack
722void ext4_mb_generate_buddy(struct super_block *sb,
723 void *buddy, void *bitmap, ext4_group_t group)
724{
725 struct ext4_group_info *grp = ext4_get_group_info(sb, group);
726 struct ext4_sb_info *sbi = EXT4_SB(sb);
727 ext4_grpblk_t max = EXT4_CLUSTERS_PER_GROUP(sb);
728 ext4_grpblk_t i = 0;
729 ext4_grpblk_t first;
730 ext4_grpblk_t len;
731 unsigned free = 0;
732 unsigned fragments = 0;
733 unsigned long long period = get_cycles();
734
735 /* initialize buddy from bitmap which is aggregation
736 * of on-disk bitmap and preallocations */
737 i = mb_find_next_zero_bit(bitmap, max, 0);
738 grp->bb_first_free = i;
739 while (i < max) {
740 fragments++;
741 first = i;
742 i = mb_find_next_bit(bitmap, max, i);
743 len = i - first;
744 free += len;
745 if (len > 1)
746 ext4_mb_mark_free_simple(sb, buddy, first, len, grp);
747 else
748 grp->bb_counters[0]++;
749 if (i < max)
750 i = mb_find_next_zero_bit(bitmap, max, i);
751 }
752 grp->bb_fragments = fragments;
753
754 if (free != grp->bb_free) {
755 ext4_grp_locked_error(sb, group, 0, 0,
756 "block bitmap and bg descriptor "
757 "inconsistent: %u vs %u free clusters",
758 free, grp->bb_free);
759 /*
760 * If we intend to continue, we consider group descriptor
761 * corrupt and update bb_free using bitmap value
762 */
763 grp->bb_free = free;
764 if (!EXT4_MB_GRP_BBITMAP_CORRUPT(grp))
765 percpu_counter_sub(&sbi->s_freeclusters_counter,
766 grp->bb_free);
767 set_bit(EXT4_GROUP_INFO_BBITMAP_CORRUPT_BIT, &grp->bb_state);
768 }
769 mb_set_largest_free_order(sb, grp);
770
771 clear_bit(EXT4_GROUP_INFO_NEED_INIT_BIT, &(grp->bb_state));
772
773 period = get_cycles() - period;
774 spin_lock(&EXT4_SB(sb)->s_bal_lock);
775 EXT4_SB(sb)->s_mb_buddies_generated++;
776 EXT4_SB(sb)->s_mb_generation_time += period;
777 spin_unlock(&EXT4_SB(sb)->s_bal_lock);
778}
779
780static void mb_regenerate_buddy(struct ext4_buddy *e4b)
781{
782 int count;
783 int order = 1;
784 void *buddy;
785
786 while ((buddy = mb_find_buddy(e4b, order++, &count))) {
787 ext4_set_bits(buddy, 0, count);
788 }
789 e4b->bd_info->bb_fragments = 0;
790 memset(e4b->bd_info->bb_counters, 0,
791 sizeof(*e4b->bd_info->bb_counters) *
792 (e4b->bd_sb->s_blocksize_bits + 2));
793
794 ext4_mb_generate_buddy(e4b->bd_sb, e4b->bd_buddy,
795 e4b->bd_bitmap, e4b->bd_group);
796}
797
798/* The buddy information is attached the buddy cache inode
799 * for convenience. The information regarding each group
800 * is loaded via ext4_mb_load_buddy. The information involve
801 * block bitmap and buddy information. The information are
802 * stored in the inode as
803 *
804 * { page }
805 * [ group 0 bitmap][ group 0 buddy] [group 1][ group 1]...
806 *
807 *
808 * one block each for bitmap and buddy information.
809 * So for each group we take up 2 blocks. A page can
810 * contain blocks_per_page (PAGE_SIZE / blocksize) blocks.
811 * So it can have information regarding groups_per_page which
812 * is blocks_per_page/2
813 *
814 * Locking note: This routine takes the block group lock of all groups
815 * for this page; do not hold this lock when calling this routine!
816 */
817
818static int ext4_mb_init_cache(struct page *page, char *incore, gfp_t gfp)
819{
820 ext4_group_t ngroups;
821 int blocksize;
822 int blocks_per_page;
823 int groups_per_page;
824 int err = 0;
825 int i;
826 ext4_group_t first_group, group;
827 int first_block;
828 struct super_block *sb;
829 struct buffer_head *bhs;
830 struct buffer_head **bh = NULL;
831 struct inode *inode;
832 char *data;
833 char *bitmap;
834 struct ext4_group_info *grinfo;
835
836 mb_debug(1, "init page %lu\n", page->index);
837
838 inode = page->mapping->host;
839 sb = inode->i_sb;
840 ngroups = ext4_get_groups_count(sb);
841 blocksize = 1 << inode->i_blkbits;
842 blocks_per_page = PAGE_SIZE / blocksize;
843
844 groups_per_page = blocks_per_page >> 1;
845 if (groups_per_page == 0)
846 groups_per_page = 1;
847
848 /* allocate buffer_heads to read bitmaps */
849 if (groups_per_page > 1) {
850 i = sizeof(struct buffer_head *) * groups_per_page;
851 bh = kzalloc(i, gfp);
852 if (bh == NULL) {
853 err = -ENOMEM;
854 goto out;
855 }
856 } else
857 bh = &bhs;
858
859 first_group = page->index * blocks_per_page / 2;
860
861 /* read all groups the page covers into the cache */
862 for (i = 0, group = first_group; i < groups_per_page; i++, group++) {
863 if (group >= ngroups)
864 break;
865
866 grinfo = ext4_get_group_info(sb, group);
867 /*
868 * If page is uptodate then we came here after online resize
869 * which added some new uninitialized group info structs, so
870 * we must skip all initialized uptodate buddies on the page,
871 * which may be currently in use by an allocating task.
872 */
873 if (PageUptodate(page) && !EXT4_MB_GRP_NEED_INIT(grinfo)) {
874 bh[i] = NULL;
875 continue;
876 }
877 bh[i] = ext4_read_block_bitmap_nowait(sb, group);
878 if (IS_ERR(bh[i])) {
879 err = PTR_ERR(bh[i]);
880 bh[i] = NULL;
881 goto out;
882 }
883 mb_debug(1, "read bitmap for group %u\n", group);
884 }
885
886 /* wait for I/O completion */
887 for (i = 0, group = first_group; i < groups_per_page; i++, group++) {
888 int err2;
889
890 if (!bh[i])
891 continue;
892 err2 = ext4_wait_block_bitmap(sb, group, bh[i]);
893 if (!err)
894 err = err2;
895 }
896
897 first_block = page->index * blocks_per_page;
898 for (i = 0; i < blocks_per_page; i++) {
899 group = (first_block + i) >> 1;
900 if (group >= ngroups)
901 break;
902
903 if (!bh[group - first_group])
904 /* skip initialized uptodate buddy */
905 continue;
906
907 if (!buffer_verified(bh[group - first_group]))
908 /* Skip faulty bitmaps */
909 continue;
910 err = 0;
911
912 /*
913 * data carry information regarding this
914 * particular group in the format specified
915 * above
916 *
917 */
918 data = page_address(page) + (i * blocksize);
919 bitmap = bh[group - first_group]->b_data;
920
921 /*
922 * We place the buddy block and bitmap block
923 * close together
924 */
925 if ((first_block + i) & 1) {
926 /* this is block of buddy */
927 BUG_ON(incore == NULL);
928 mb_debug(1, "put buddy for group %u in page %lu/%x\n",
929 group, page->index, i * blocksize);
930 trace_ext4_mb_buddy_bitmap_load(sb, group);
931 grinfo = ext4_get_group_info(sb, group);
932 grinfo->bb_fragments = 0;
933 memset(grinfo->bb_counters, 0,
934 sizeof(*grinfo->bb_counters) *
935 (sb->s_blocksize_bits+2));
936 /*
937 * incore got set to the group block bitmap below
938 */
939 ext4_lock_group(sb, group);
940 /* init the buddy */
941 memset(data, 0xff, blocksize);
942 ext4_mb_generate_buddy(sb, data, incore, group);
943 ext4_unlock_group(sb, group);
944 incore = NULL;
945 } else {
946 /* this is block of bitmap */
947 BUG_ON(incore != NULL);
948 mb_debug(1, "put bitmap for group %u in page %lu/%x\n",
949 group, page->index, i * blocksize);
950 trace_ext4_mb_bitmap_load(sb, group);
951
952 /* see comments in ext4_mb_put_pa() */
953 ext4_lock_group(sb, group);
954 memcpy(data, bitmap, blocksize);
955
956 /* mark all preallocated blks used in in-core bitmap */
957 ext4_mb_generate_from_pa(sb, data, group);
958 ext4_mb_generate_from_freelist(sb, data, group);
959 ext4_unlock_group(sb, group);
960
961 /* set incore so that the buddy information can be
962 * generated using this
963 */
964 incore = data;
965 }
966 }
967 SetPageUptodate(page);
968
969out:
970 if (bh) {
971 for (i = 0; i < groups_per_page; i++)
972 brelse(bh[i]);
973 if (bh != &bhs)
974 kfree(bh);
975 }
976 return err;
977}
978
979/*
980 * Lock the buddy and bitmap pages. This make sure other parallel init_group
981 * on the same buddy page doesn't happen whild holding the buddy page lock.
982 * Return locked buddy and bitmap pages on e4b struct. If buddy and bitmap
983 * are on the same page e4b->bd_buddy_page is NULL and return value is 0.
984 */
985static int ext4_mb_get_buddy_page_lock(struct super_block *sb,
986 ext4_group_t group, struct ext4_buddy *e4b, gfp_t gfp)
987{
988 struct inode *inode = EXT4_SB(sb)->s_buddy_cache;
989 int block, pnum, poff;
990 int blocks_per_page;
991 struct page *page;
992
993 e4b->bd_buddy_page = NULL;
994 e4b->bd_bitmap_page = NULL;
995
996 blocks_per_page = PAGE_SIZE / sb->s_blocksize;
997 /*
998 * the buddy cache inode stores the block bitmap
999 * and buddy information in consecutive blocks.
1000 * So for each group we need two blocks.
1001 */
1002 block = group * 2;
1003 pnum = block / blocks_per_page;
1004 poff = block % blocks_per_page;
1005 page = find_or_create_page(inode->i_mapping, pnum, gfp);
1006 if (!page)
1007 return -ENOMEM;
1008 BUG_ON(page->mapping != inode->i_mapping);
1009 e4b->bd_bitmap_page = page;
1010 e4b->bd_bitmap = page_address(page) + (poff * sb->s_blocksize);
1011
1012 if (blocks_per_page >= 2) {
1013 /* buddy and bitmap are on the same page */
1014 return 0;
1015 }
1016
1017 block++;
1018 pnum = block / blocks_per_page;
1019 page = find_or_create_page(inode->i_mapping, pnum, gfp);
1020 if (!page)
1021 return -ENOMEM;
1022 BUG_ON(page->mapping != inode->i_mapping);
1023 e4b->bd_buddy_page = page;
1024 return 0;
1025}
1026
1027static void ext4_mb_put_buddy_page_lock(struct ext4_buddy *e4b)
1028{
1029 if (e4b->bd_bitmap_page) {
1030 unlock_page(e4b->bd_bitmap_page);
1031 put_page(e4b->bd_bitmap_page);
1032 }
1033 if (e4b->bd_buddy_page) {
1034 unlock_page(e4b->bd_buddy_page);
1035 put_page(e4b->bd_buddy_page);
1036 }
1037}
1038
1039/*
1040 * Locking note: This routine calls ext4_mb_init_cache(), which takes the
1041 * block group lock of all groups for this page; do not hold the BG lock when
1042 * calling this routine!
1043 */
1044static noinline_for_stack
1045int ext4_mb_init_group(struct super_block *sb, ext4_group_t group, gfp_t gfp)
1046{
1047
1048 struct ext4_group_info *this_grp;
1049 struct ext4_buddy e4b;
1050 struct page *page;
1051 int ret = 0;
1052
1053 might_sleep();
1054 mb_debug(1, "init group %u\n", group);
1055 this_grp = ext4_get_group_info(sb, group);
1056 /*
1057 * This ensures that we don't reinit the buddy cache
1058 * page which map to the group from which we are already
1059 * allocating. If we are looking at the buddy cache we would
1060 * have taken a reference using ext4_mb_load_buddy and that
1061 * would have pinned buddy page to page cache.
1062 * The call to ext4_mb_get_buddy_page_lock will mark the
1063 * page accessed.
1064 */
1065 ret = ext4_mb_get_buddy_page_lock(sb, group, &e4b, gfp);
1066 if (ret || !EXT4_MB_GRP_NEED_INIT(this_grp)) {
1067 /*
1068 * somebody initialized the group
1069 * return without doing anything
1070 */
1071 goto err;
1072 }
1073
1074 page = e4b.bd_bitmap_page;
1075 ret = ext4_mb_init_cache(page, NULL, gfp);
1076 if (ret)
1077 goto err;
1078 if (!PageUptodate(page)) {
1079 ret = -EIO;
1080 goto err;
1081 }
1082
1083 if (e4b.bd_buddy_page == NULL) {
1084 /*
1085 * If both the bitmap and buddy are in
1086 * the same page we don't need to force
1087 * init the buddy
1088 */
1089 ret = 0;
1090 goto err;
1091 }
1092 /* init buddy cache */
1093 page = e4b.bd_buddy_page;
1094 ret = ext4_mb_init_cache(page, e4b.bd_bitmap, gfp);
1095 if (ret)
1096 goto err;
1097 if (!PageUptodate(page)) {
1098 ret = -EIO;
1099 goto err;
1100 }
1101err:
1102 ext4_mb_put_buddy_page_lock(&e4b);
1103 return ret;
1104}
1105
1106/*
1107 * Locking note: This routine calls ext4_mb_init_cache(), which takes the
1108 * block group lock of all groups for this page; do not hold the BG lock when
1109 * calling this routine!
1110 */
1111static noinline_for_stack int
1112ext4_mb_load_buddy_gfp(struct super_block *sb, ext4_group_t group,
1113 struct ext4_buddy *e4b, gfp_t gfp)
1114{
1115 int blocks_per_page;
1116 int block;
1117 int pnum;
1118 int poff;
1119 struct page *page;
1120 int ret;
1121 struct ext4_group_info *grp;
1122 struct ext4_sb_info *sbi = EXT4_SB(sb);
1123 struct inode *inode = sbi->s_buddy_cache;
1124
1125 might_sleep();
1126 mb_debug(1, "load group %u\n", group);
1127
1128 blocks_per_page = PAGE_SIZE / sb->s_blocksize;
1129 grp = ext4_get_group_info(sb, group);
1130
1131 e4b->bd_blkbits = sb->s_blocksize_bits;
1132 e4b->bd_info = grp;
1133 e4b->bd_sb = sb;
1134 e4b->bd_group = group;
1135 e4b->bd_buddy_page = NULL;
1136 e4b->bd_bitmap_page = NULL;
1137
1138 if (unlikely(EXT4_MB_GRP_NEED_INIT(grp))) {
1139 /*
1140 * we need full data about the group
1141 * to make a good selection
1142 */
1143 ret = ext4_mb_init_group(sb, group, gfp);
1144 if (ret)
1145 return ret;
1146 }
1147
1148 /*
1149 * the buddy cache inode stores the block bitmap
1150 * and buddy information in consecutive blocks.
1151 * So for each group we need two blocks.
1152 */
1153 block = group * 2;
1154 pnum = block / blocks_per_page;
1155 poff = block % blocks_per_page;
1156
1157 /* we could use find_or_create_page(), but it locks page
1158 * what we'd like to avoid in fast path ... */
1159 page = find_get_page_flags(inode->i_mapping, pnum, FGP_ACCESSED);
1160 if (page == NULL || !PageUptodate(page)) {
1161 if (page)
1162 /*
1163 * drop the page reference and try
1164 * to get the page with lock. If we
1165 * are not uptodate that implies
1166 * somebody just created the page but
1167 * is yet to initialize the same. So
1168 * wait for it to initialize.
1169 */
1170 put_page(page);
1171 page = find_or_create_page(inode->i_mapping, pnum, gfp);
1172 if (page) {
1173 BUG_ON(page->mapping != inode->i_mapping);
1174 if (!PageUptodate(page)) {
1175 ret = ext4_mb_init_cache(page, NULL, gfp);
1176 if (ret) {
1177 unlock_page(page);
1178 goto err;
1179 }
1180 mb_cmp_bitmaps(e4b, page_address(page) +
1181 (poff * sb->s_blocksize));
1182 }
1183 unlock_page(page);
1184 }
1185 }
1186 if (page == NULL) {
1187 ret = -ENOMEM;
1188 goto err;
1189 }
1190 if (!PageUptodate(page)) {
1191 ret = -EIO;
1192 goto err;
1193 }
1194
1195 /* Pages marked accessed already */
1196 e4b->bd_bitmap_page = page;
1197 e4b->bd_bitmap = page_address(page) + (poff * sb->s_blocksize);
1198
1199 block++;
1200 pnum = block / blocks_per_page;
1201 poff = block % blocks_per_page;
1202
1203 page = find_get_page_flags(inode->i_mapping, pnum, FGP_ACCESSED);
1204 if (page == NULL || !PageUptodate(page)) {
1205 if (page)
1206 put_page(page);
1207 page = find_or_create_page(inode->i_mapping, pnum, gfp);
1208 if (page) {
1209 BUG_ON(page->mapping != inode->i_mapping);
1210 if (!PageUptodate(page)) {
1211 ret = ext4_mb_init_cache(page, e4b->bd_bitmap,
1212 gfp);
1213 if (ret) {
1214 unlock_page(page);
1215 goto err;
1216 }
1217 }
1218 unlock_page(page);
1219 }
1220 }
1221 if (page == NULL) {
1222 ret = -ENOMEM;
1223 goto err;
1224 }
1225 if (!PageUptodate(page)) {
1226 ret = -EIO;
1227 goto err;
1228 }
1229
1230 /* Pages marked accessed already */
1231 e4b->bd_buddy_page = page;
1232 e4b->bd_buddy = page_address(page) + (poff * sb->s_blocksize);
1233
1234 BUG_ON(e4b->bd_bitmap_page == NULL);
1235 BUG_ON(e4b->bd_buddy_page == NULL);
1236
1237 return 0;
1238
1239err:
1240 if (page)
1241 put_page(page);
1242 if (e4b->bd_bitmap_page)
1243 put_page(e4b->bd_bitmap_page);
1244 if (e4b->bd_buddy_page)
1245 put_page(e4b->bd_buddy_page);
1246 e4b->bd_buddy = NULL;
1247 e4b->bd_bitmap = NULL;
1248 return ret;
1249}
1250
1251static int ext4_mb_load_buddy(struct super_block *sb, ext4_group_t group,
1252 struct ext4_buddy *e4b)
1253{
1254 return ext4_mb_load_buddy_gfp(sb, group, e4b, GFP_NOFS);
1255}
1256
1257static void ext4_mb_unload_buddy(struct ext4_buddy *e4b)
1258{
1259 if (e4b->bd_bitmap_page)
1260 put_page(e4b->bd_bitmap_page);
1261 if (e4b->bd_buddy_page)
1262 put_page(e4b->bd_buddy_page);
1263}
1264
1265
1266static int mb_find_order_for_block(struct ext4_buddy *e4b, int block)
1267{
1268 int order = 1;
1269 void *bb;
1270
1271 BUG_ON(e4b->bd_bitmap == e4b->bd_buddy);
1272 BUG_ON(block >= (1 << (e4b->bd_blkbits + 3)));
1273
1274 bb = e4b->bd_buddy;
1275 while (order <= e4b->bd_blkbits + 1) {
1276 block = block >> 1;
1277 if (!mb_test_bit(block, bb)) {
1278 /* this block is part of buddy of order 'order' */
1279 return order;
1280 }
1281 bb += 1 << (e4b->bd_blkbits - order);
1282 order++;
1283 }
1284 return 0;
1285}
1286
1287static void mb_clear_bits(void *bm, int cur, int len)
1288{
1289 __u32 *addr;
1290
1291 len = cur + len;
1292 while (cur < len) {
1293 if ((cur & 31) == 0 && (len - cur) >= 32) {
1294 /* fast path: clear whole word at once */
1295 addr = bm + (cur >> 3);
1296 *addr = 0;
1297 cur += 32;
1298 continue;
1299 }
1300 mb_clear_bit(cur, bm);
1301 cur++;
1302 }
1303}
1304
1305/* clear bits in given range
1306 * will return first found zero bit if any, -1 otherwise
1307 */
1308static int mb_test_and_clear_bits(void *bm, int cur, int len)
1309{
1310 __u32 *addr;
1311 int zero_bit = -1;
1312
1313 len = cur + len;
1314 while (cur < len) {
1315 if ((cur & 31) == 0 && (len - cur) >= 32) {
1316 /* fast path: clear whole word at once */
1317 addr = bm + (cur >> 3);
1318 if (*addr != (__u32)(-1) && zero_bit == -1)
1319 zero_bit = cur + mb_find_next_zero_bit(addr, 32, 0);
1320 *addr = 0;
1321 cur += 32;
1322 continue;
1323 }
1324 if (!mb_test_and_clear_bit(cur, bm) && zero_bit == -1)
1325 zero_bit = cur;
1326 cur++;
1327 }
1328
1329 return zero_bit;
1330}
1331
1332void ext4_set_bits(void *bm, int cur, int len)
1333{
1334 __u32 *addr;
1335
1336 len = cur + len;
1337 while (cur < len) {
1338 if ((cur & 31) == 0 && (len - cur) >= 32) {
1339 /* fast path: set whole word at once */
1340 addr = bm + (cur >> 3);
1341 *addr = 0xffffffff;
1342 cur += 32;
1343 continue;
1344 }
1345 mb_set_bit(cur, bm);
1346 cur++;
1347 }
1348}
1349
1350/*
1351 * _________________________________________________________________ */
1352
1353static inline int mb_buddy_adjust_border(int* bit, void* bitmap, int side)
1354{
1355 if (mb_test_bit(*bit + side, bitmap)) {
1356 mb_clear_bit(*bit, bitmap);
1357 (*bit) -= side;
1358 return 1;
1359 }
1360 else {
1361 (*bit) += side;
1362 mb_set_bit(*bit, bitmap);
1363 return -1;
1364 }
1365}
1366
1367static void mb_buddy_mark_free(struct ext4_buddy *e4b, int first, int last)
1368{
1369 int max;
1370 int order = 1;
1371 void *buddy = mb_find_buddy(e4b, order, &max);
1372
1373 while (buddy) {
1374 void *buddy2;
1375
1376 /* Bits in range [first; last] are known to be set since
1377 * corresponding blocks were allocated. Bits in range
1378 * (first; last) will stay set because they form buddies on
1379 * upper layer. We just deal with borders if they don't
1380 * align with upper layer and then go up.
1381 * Releasing entire group is all about clearing
1382 * single bit of highest order buddy.
1383 */
1384
1385 /* Example:
1386 * ---------------------------------
1387 * | 1 | 1 | 1 | 1 |
1388 * ---------------------------------
1389 * | 0 | 1 | 1 | 1 | 1 | 1 | 1 | 1 |
1390 * ---------------------------------
1391 * 0 1 2 3 4 5 6 7
1392 * \_____________________/
1393 *
1394 * Neither [1] nor [6] is aligned to above layer.
1395 * Left neighbour [0] is free, so mark it busy,
1396 * decrease bb_counters and extend range to
1397 * [0; 6]
1398 * Right neighbour [7] is busy. It can't be coaleasced with [6], so
1399 * mark [6] free, increase bb_counters and shrink range to
1400 * [0; 5].
1401 * Then shift range to [0; 2], go up and do the same.
1402 */
1403
1404
1405 if (first & 1)
1406 e4b->bd_info->bb_counters[order] += mb_buddy_adjust_border(&first, buddy, -1);
1407 if (!(last & 1))
1408 e4b->bd_info->bb_counters[order] += mb_buddy_adjust_border(&last, buddy, 1);
1409 if (first > last)
1410 break;
1411 order++;
1412
1413 if (first == last || !(buddy2 = mb_find_buddy(e4b, order, &max))) {
1414 mb_clear_bits(buddy, first, last - first + 1);
1415 e4b->bd_info->bb_counters[order - 1] += last - first + 1;
1416 break;
1417 }
1418 first >>= 1;
1419 last >>= 1;
1420 buddy = buddy2;
1421 }
1422}
1423
1424static void mb_free_blocks(struct inode *inode, struct ext4_buddy *e4b,
1425 int first, int count)
1426{
1427 int left_is_free = 0;
1428 int right_is_free = 0;
1429 int block;
1430 int last = first + count - 1;
1431 struct super_block *sb = e4b->bd_sb;
1432
1433 if (WARN_ON(count == 0))
1434 return;
1435 BUG_ON(last >= (sb->s_blocksize << 3));
1436 assert_spin_locked(ext4_group_lock_ptr(sb, e4b->bd_group));
1437 /* Don't bother if the block group is corrupt. */
1438 if (unlikely(EXT4_MB_GRP_BBITMAP_CORRUPT(e4b->bd_info)))
1439 return;
1440
1441 mb_check_buddy(e4b);
1442 mb_free_blocks_double(inode, e4b, first, count);
1443
1444 e4b->bd_info->bb_free += count;
1445 if (first < e4b->bd_info->bb_first_free)
1446 e4b->bd_info->bb_first_free = first;
1447
1448 /* access memory sequentially: check left neighbour,
1449 * clear range and then check right neighbour
1450 */
1451 if (first != 0)
1452 left_is_free = !mb_test_bit(first - 1, e4b->bd_bitmap);
1453 block = mb_test_and_clear_bits(e4b->bd_bitmap, first, count);
1454 if (last + 1 < EXT4_SB(sb)->s_mb_maxs[0])
1455 right_is_free = !mb_test_bit(last + 1, e4b->bd_bitmap);
1456
1457 if (unlikely(block != -1)) {
1458 struct ext4_sb_info *sbi = EXT4_SB(sb);
1459 ext4_fsblk_t blocknr;
1460
1461 blocknr = ext4_group_first_block_no(sb, e4b->bd_group);
1462 blocknr += EXT4_C2B(EXT4_SB(sb), block);
1463 ext4_grp_locked_error(sb, e4b->bd_group,
1464 inode ? inode->i_ino : 0,
1465 blocknr,
1466 "freeing already freed block "
1467 "(bit %u); block bitmap corrupt.",
1468 block);
1469 if (!EXT4_MB_GRP_BBITMAP_CORRUPT(e4b->bd_info))
1470 percpu_counter_sub(&sbi->s_freeclusters_counter,
1471 e4b->bd_info->bb_free);
1472 /* Mark the block group as corrupt. */
1473 set_bit(EXT4_GROUP_INFO_BBITMAP_CORRUPT_BIT,
1474 &e4b->bd_info->bb_state);
1475 mb_regenerate_buddy(e4b);
1476 goto done;
1477 }
1478
1479 /* let's maintain fragments counter */
1480 if (left_is_free && right_is_free)
1481 e4b->bd_info->bb_fragments--;
1482 else if (!left_is_free && !right_is_free)
1483 e4b->bd_info->bb_fragments++;
1484
1485 /* buddy[0] == bd_bitmap is a special case, so handle
1486 * it right away and let mb_buddy_mark_free stay free of
1487 * zero order checks.
1488 * Check if neighbours are to be coaleasced,
1489 * adjust bitmap bb_counters and borders appropriately.
1490 */
1491 if (first & 1) {
1492 first += !left_is_free;
1493 e4b->bd_info->bb_counters[0] += left_is_free ? -1 : 1;
1494 }
1495 if (!(last & 1)) {
1496 last -= !right_is_free;
1497 e4b->bd_info->bb_counters[0] += right_is_free ? -1 : 1;
1498 }
1499
1500 if (first <= last)
1501 mb_buddy_mark_free(e4b, first >> 1, last >> 1);
1502
1503done:
1504 mb_set_largest_free_order(sb, e4b->bd_info);
1505 mb_check_buddy(e4b);
1506}
1507
1508static int mb_find_extent(struct ext4_buddy *e4b, int block,
1509 int needed, struct ext4_free_extent *ex)
1510{
1511 int next = block;
1512 int max, order;
1513 void *buddy;
1514
1515 assert_spin_locked(ext4_group_lock_ptr(e4b->bd_sb, e4b->bd_group));
1516 BUG_ON(ex == NULL);
1517
1518 buddy = mb_find_buddy(e4b, 0, &max);
1519 BUG_ON(buddy == NULL);
1520 BUG_ON(block >= max);
1521 if (mb_test_bit(block, buddy)) {
1522 ex->fe_len = 0;
1523 ex->fe_start = 0;
1524 ex->fe_group = 0;
1525 return 0;
1526 }
1527
1528 /* find actual order */
1529 order = mb_find_order_for_block(e4b, block);
1530 block = block >> order;
1531
1532 ex->fe_len = 1 << order;
1533 ex->fe_start = block << order;
1534 ex->fe_group = e4b->bd_group;
1535
1536 /* calc difference from given start */
1537 next = next - ex->fe_start;
1538 ex->fe_len -= next;
1539 ex->fe_start += next;
1540
1541 while (needed > ex->fe_len &&
1542 mb_find_buddy(e4b, order, &max)) {
1543
1544 if (block + 1 >= max)
1545 break;
1546
1547 next = (block + 1) * (1 << order);
1548 if (mb_test_bit(next, e4b->bd_bitmap))
1549 break;
1550
1551 order = mb_find_order_for_block(e4b, next);
1552
1553 block = next >> order;
1554 ex->fe_len += 1 << order;
1555 }
1556
1557 BUG_ON(ex->fe_start + ex->fe_len > (1 << (e4b->bd_blkbits + 3)));
1558 return ex->fe_len;
1559}
1560
1561static int mb_mark_used(struct ext4_buddy *e4b, struct ext4_free_extent *ex)
1562{
1563 int ord;
1564 int mlen = 0;
1565 int max = 0;
1566 int cur;
1567 int start = ex->fe_start;
1568 int len = ex->fe_len;
1569 unsigned ret = 0;
1570 int len0 = len;
1571 void *buddy;
1572
1573 BUG_ON(start + len > (e4b->bd_sb->s_blocksize << 3));
1574 BUG_ON(e4b->bd_group != ex->fe_group);
1575 assert_spin_locked(ext4_group_lock_ptr(e4b->bd_sb, e4b->bd_group));
1576 mb_check_buddy(e4b);
1577 mb_mark_used_double(e4b, start, len);
1578
1579 e4b->bd_info->bb_free -= len;
1580 if (e4b->bd_info->bb_first_free == start)
1581 e4b->bd_info->bb_first_free += len;
1582
1583 /* let's maintain fragments counter */
1584 if (start != 0)
1585 mlen = !mb_test_bit(start - 1, e4b->bd_bitmap);
1586 if (start + len < EXT4_SB(e4b->bd_sb)->s_mb_maxs[0])
1587 max = !mb_test_bit(start + len, e4b->bd_bitmap);
1588 if (mlen && max)
1589 e4b->bd_info->bb_fragments++;
1590 else if (!mlen && !max)
1591 e4b->bd_info->bb_fragments--;
1592
1593 /* let's maintain buddy itself */
1594 while (len) {
1595 ord = mb_find_order_for_block(e4b, start);
1596
1597 if (((start >> ord) << ord) == start && len >= (1 << ord)) {
1598 /* the whole chunk may be allocated at once! */
1599 mlen = 1 << ord;
1600 buddy = mb_find_buddy(e4b, ord, &max);
1601 BUG_ON((start >> ord) >= max);
1602 mb_set_bit(start >> ord, buddy);
1603 e4b->bd_info->bb_counters[ord]--;
1604 start += mlen;
1605 len -= mlen;
1606 BUG_ON(len < 0);
1607 continue;
1608 }
1609
1610 /* store for history */
1611 if (ret == 0)
1612 ret = len | (ord << 16);
1613
1614 /* we have to split large buddy */
1615 BUG_ON(ord <= 0);
1616 buddy = mb_find_buddy(e4b, ord, &max);
1617 mb_set_bit(start >> ord, buddy);
1618 e4b->bd_info->bb_counters[ord]--;
1619
1620 ord--;
1621 cur = (start >> ord) & ~1U;
1622 buddy = mb_find_buddy(e4b, ord, &max);
1623 mb_clear_bit(cur, buddy);
1624 mb_clear_bit(cur + 1, buddy);
1625 e4b->bd_info->bb_counters[ord]++;
1626 e4b->bd_info->bb_counters[ord]++;
1627 }
1628 mb_set_largest_free_order(e4b->bd_sb, e4b->bd_info);
1629
1630 ext4_set_bits(e4b->bd_bitmap, ex->fe_start, len0);
1631 mb_check_buddy(e4b);
1632
1633 return ret;
1634}
1635
1636/*
1637 * Must be called under group lock!
1638 */
1639static void ext4_mb_use_best_found(struct ext4_allocation_context *ac,
1640 struct ext4_buddy *e4b)
1641{
1642 struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
1643 int ret;
1644
1645 BUG_ON(ac->ac_b_ex.fe_group != e4b->bd_group);
1646 BUG_ON(ac->ac_status == AC_STATUS_FOUND);
1647
1648 ac->ac_b_ex.fe_len = min(ac->ac_b_ex.fe_len, ac->ac_g_ex.fe_len);
1649 ac->ac_b_ex.fe_logical = ac->ac_g_ex.fe_logical;
1650 ret = mb_mark_used(e4b, &ac->ac_b_ex);
1651
1652 /* preallocation can change ac_b_ex, thus we store actually
1653 * allocated blocks for history */
1654 ac->ac_f_ex = ac->ac_b_ex;
1655
1656 ac->ac_status = AC_STATUS_FOUND;
1657 ac->ac_tail = ret & 0xffff;
1658 ac->ac_buddy = ret >> 16;
1659
1660 /*
1661 * take the page reference. We want the page to be pinned
1662 * so that we don't get a ext4_mb_init_cache_call for this
1663 * group until we update the bitmap. That would mean we
1664 * double allocate blocks. The reference is dropped
1665 * in ext4_mb_release_context
1666 */
1667 ac->ac_bitmap_page = e4b->bd_bitmap_page;
1668 get_page(ac->ac_bitmap_page);
1669 ac->ac_buddy_page = e4b->bd_buddy_page;
1670 get_page(ac->ac_buddy_page);
1671 /* store last allocated for subsequent stream allocation */
1672 if (ac->ac_flags & EXT4_MB_STREAM_ALLOC) {
1673 spin_lock(&sbi->s_md_lock);
1674 sbi->s_mb_last_group = ac->ac_f_ex.fe_group;
1675 sbi->s_mb_last_start = ac->ac_f_ex.fe_start;
1676 spin_unlock(&sbi->s_md_lock);
1677 }
1678}
1679
1680/*
1681 * regular allocator, for general purposes allocation
1682 */
1683
1684static void ext4_mb_check_limits(struct ext4_allocation_context *ac,
1685 struct ext4_buddy *e4b,
1686 int finish_group)
1687{
1688 struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
1689 struct ext4_free_extent *bex = &ac->ac_b_ex;
1690 struct ext4_free_extent *gex = &ac->ac_g_ex;
1691 struct ext4_free_extent ex;
1692 int max;
1693
1694 if (ac->ac_status == AC_STATUS_FOUND)
1695 return;
1696 /*
1697 * We don't want to scan for a whole year
1698 */
1699 if (ac->ac_found > sbi->s_mb_max_to_scan &&
1700 !(ac->ac_flags & EXT4_MB_HINT_FIRST)) {
1701 ac->ac_status = AC_STATUS_BREAK;
1702 return;
1703 }
1704
1705 /*
1706 * Haven't found good chunk so far, let's continue
1707 */
1708 if (bex->fe_len < gex->fe_len)
1709 return;
1710
1711 if ((finish_group || ac->ac_found > sbi->s_mb_min_to_scan)
1712 && bex->fe_group == e4b->bd_group) {
1713 /* recheck chunk's availability - we don't know
1714 * when it was found (within this lock-unlock
1715 * period or not) */
1716 max = mb_find_extent(e4b, bex->fe_start, gex->fe_len, &ex);
1717 if (max >= gex->fe_len) {
1718 ext4_mb_use_best_found(ac, e4b);
1719 return;
1720 }
1721 }
1722}
1723
1724/*
1725 * The routine checks whether found extent is good enough. If it is,
1726 * then the extent gets marked used and flag is set to the context
1727 * to stop scanning. Otherwise, the extent is compared with the
1728 * previous found extent and if new one is better, then it's stored
1729 * in the context. Later, the best found extent will be used, if
1730 * mballoc can't find good enough extent.
1731 *
1732 * FIXME: real allocation policy is to be designed yet!
1733 */
1734static void ext4_mb_measure_extent(struct ext4_allocation_context *ac,
1735 struct ext4_free_extent *ex,
1736 struct ext4_buddy *e4b)
1737{
1738 struct ext4_free_extent *bex = &ac->ac_b_ex;
1739 struct ext4_free_extent *gex = &ac->ac_g_ex;
1740
1741 BUG_ON(ex->fe_len <= 0);
1742 BUG_ON(ex->fe_len > EXT4_CLUSTERS_PER_GROUP(ac->ac_sb));
1743 BUG_ON(ex->fe_start >= EXT4_CLUSTERS_PER_GROUP(ac->ac_sb));
1744 BUG_ON(ac->ac_status != AC_STATUS_CONTINUE);
1745
1746 ac->ac_found++;
1747
1748 /*
1749 * The special case - take what you catch first
1750 */
1751 if (unlikely(ac->ac_flags & EXT4_MB_HINT_FIRST)) {
1752 *bex = *ex;
1753 ext4_mb_use_best_found(ac, e4b);
1754 return;
1755 }
1756
1757 /*
1758 * Let's check whether the chuck is good enough
1759 */
1760 if (ex->fe_len == gex->fe_len) {
1761 *bex = *ex;
1762 ext4_mb_use_best_found(ac, e4b);
1763 return;
1764 }
1765
1766 /*
1767 * If this is first found extent, just store it in the context
1768 */
1769 if (bex->fe_len == 0) {
1770 *bex = *ex;
1771 return;
1772 }
1773
1774 /*
1775 * If new found extent is better, store it in the context
1776 */
1777 if (bex->fe_len < gex->fe_len) {
1778 /* if the request isn't satisfied, any found extent
1779 * larger than previous best one is better */
1780 if (ex->fe_len > bex->fe_len)
1781 *bex = *ex;
1782 } else if (ex->fe_len > gex->fe_len) {
1783 /* if the request is satisfied, then we try to find
1784 * an extent that still satisfy the request, but is
1785 * smaller than previous one */
1786 if (ex->fe_len < bex->fe_len)
1787 *bex = *ex;
1788 }
1789
1790 ext4_mb_check_limits(ac, e4b, 0);
1791}
1792
1793static noinline_for_stack
1794int ext4_mb_try_best_found(struct ext4_allocation_context *ac,
1795 struct ext4_buddy *e4b)
1796{
1797 struct ext4_free_extent ex = ac->ac_b_ex;
1798 ext4_group_t group = ex.fe_group;
1799 int max;
1800 int err;
1801
1802 BUG_ON(ex.fe_len <= 0);
1803 err = ext4_mb_load_buddy(ac->ac_sb, group, e4b);
1804 if (err)
1805 return err;
1806
1807 ext4_lock_group(ac->ac_sb, group);
1808 max = mb_find_extent(e4b, ex.fe_start, ex.fe_len, &ex);
1809
1810 if (max > 0) {
1811 ac->ac_b_ex = ex;
1812 ext4_mb_use_best_found(ac, e4b);
1813 }
1814
1815 ext4_unlock_group(ac->ac_sb, group);
1816 ext4_mb_unload_buddy(e4b);
1817
1818 return 0;
1819}
1820
1821static noinline_for_stack
1822int ext4_mb_find_by_goal(struct ext4_allocation_context *ac,
1823 struct ext4_buddy *e4b)
1824{
1825 ext4_group_t group = ac->ac_g_ex.fe_group;
1826 int max;
1827 int err;
1828 struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
1829 struct ext4_group_info *grp = ext4_get_group_info(ac->ac_sb, group);
1830 struct ext4_free_extent ex;
1831
1832 if (!(ac->ac_flags & EXT4_MB_HINT_TRY_GOAL))
1833 return 0;
1834 if (grp->bb_free == 0)
1835 return 0;
1836
1837 err = ext4_mb_load_buddy(ac->ac_sb, group, e4b);
1838 if (err)
1839 return err;
1840
1841 if (unlikely(EXT4_MB_GRP_BBITMAP_CORRUPT(e4b->bd_info))) {
1842 ext4_mb_unload_buddy(e4b);
1843 return 0;
1844 }
1845
1846 ext4_lock_group(ac->ac_sb, group);
1847 max = mb_find_extent(e4b, ac->ac_g_ex.fe_start,
1848 ac->ac_g_ex.fe_len, &ex);
1849 ex.fe_logical = 0xDEADFA11; /* debug value */
1850
1851 if (max >= ac->ac_g_ex.fe_len && ac->ac_g_ex.fe_len == sbi->s_stripe) {
1852 ext4_fsblk_t start;
1853
1854 start = ext4_group_first_block_no(ac->ac_sb, e4b->bd_group) +
1855 ex.fe_start;
1856 /* use do_div to get remainder (would be 64-bit modulo) */
1857 if (do_div(start, sbi->s_stripe) == 0) {
1858 ac->ac_found++;
1859 ac->ac_b_ex = ex;
1860 ext4_mb_use_best_found(ac, e4b);
1861 }
1862 } else if (max >= ac->ac_g_ex.fe_len) {
1863 BUG_ON(ex.fe_len <= 0);
1864 BUG_ON(ex.fe_group != ac->ac_g_ex.fe_group);
1865 BUG_ON(ex.fe_start != ac->ac_g_ex.fe_start);
1866 ac->ac_found++;
1867 ac->ac_b_ex = ex;
1868 ext4_mb_use_best_found(ac, e4b);
1869 } else if (max > 0 && (ac->ac_flags & EXT4_MB_HINT_MERGE)) {
1870 /* Sometimes, caller may want to merge even small
1871 * number of blocks to an existing extent */
1872 BUG_ON(ex.fe_len <= 0);
1873 BUG_ON(ex.fe_group != ac->ac_g_ex.fe_group);
1874 BUG_ON(ex.fe_start != ac->ac_g_ex.fe_start);
1875 ac->ac_found++;
1876 ac->ac_b_ex = ex;
1877 ext4_mb_use_best_found(ac, e4b);
1878 }
1879 ext4_unlock_group(ac->ac_sb, group);
1880 ext4_mb_unload_buddy(e4b);
1881
1882 return 0;
1883}
1884
1885/*
1886 * The routine scans buddy structures (not bitmap!) from given order
1887 * to max order and tries to find big enough chunk to satisfy the req
1888 */
1889static noinline_for_stack
1890void ext4_mb_simple_scan_group(struct ext4_allocation_context *ac,
1891 struct ext4_buddy *e4b)
1892{
1893 struct super_block *sb = ac->ac_sb;
1894 struct ext4_group_info *grp = e4b->bd_info;
1895 void *buddy;
1896 int i;
1897 int k;
1898 int max;
1899
1900 BUG_ON(ac->ac_2order <= 0);
1901 for (i = ac->ac_2order; i <= sb->s_blocksize_bits + 1; i++) {
1902 if (grp->bb_counters[i] == 0)
1903 continue;
1904
1905 buddy = mb_find_buddy(e4b, i, &max);
1906 BUG_ON(buddy == NULL);
1907
1908 k = mb_find_next_zero_bit(buddy, max, 0);
1909 BUG_ON(k >= max);
1910
1911 ac->ac_found++;
1912
1913 ac->ac_b_ex.fe_len = 1 << i;
1914 ac->ac_b_ex.fe_start = k << i;
1915 ac->ac_b_ex.fe_group = e4b->bd_group;
1916
1917 ext4_mb_use_best_found(ac, e4b);
1918
1919 BUG_ON(ac->ac_b_ex.fe_len != ac->ac_g_ex.fe_len);
1920
1921 if (EXT4_SB(sb)->s_mb_stats)
1922 atomic_inc(&EXT4_SB(sb)->s_bal_2orders);
1923
1924 break;
1925 }
1926}
1927
1928/*
1929 * The routine scans the group and measures all found extents.
1930 * In order to optimize scanning, caller must pass number of
1931 * free blocks in the group, so the routine can know upper limit.
1932 */
1933static noinline_for_stack
1934void ext4_mb_complex_scan_group(struct ext4_allocation_context *ac,
1935 struct ext4_buddy *e4b)
1936{
1937 struct super_block *sb = ac->ac_sb;
1938 void *bitmap = e4b->bd_bitmap;
1939 struct ext4_free_extent ex;
1940 int i;
1941 int free;
1942
1943 free = e4b->bd_info->bb_free;
1944 BUG_ON(free <= 0);
1945
1946 i = e4b->bd_info->bb_first_free;
1947
1948 while (free && ac->ac_status == AC_STATUS_CONTINUE) {
1949 i = mb_find_next_zero_bit(bitmap,
1950 EXT4_CLUSTERS_PER_GROUP(sb), i);
1951 if (i >= EXT4_CLUSTERS_PER_GROUP(sb)) {
1952 /*
1953 * IF we have corrupt bitmap, we won't find any
1954 * free blocks even though group info says we
1955 * we have free blocks
1956 */
1957 ext4_grp_locked_error(sb, e4b->bd_group, 0, 0,
1958 "%d free clusters as per "
1959 "group info. But bitmap says 0",
1960 free);
1961 break;
1962 }
1963
1964 mb_find_extent(e4b, i, ac->ac_g_ex.fe_len, &ex);
1965 BUG_ON(ex.fe_len <= 0);
1966 if (free < ex.fe_len) {
1967 ext4_grp_locked_error(sb, e4b->bd_group, 0, 0,
1968 "%d free clusters as per "
1969 "group info. But got %d blocks",
1970 free, ex.fe_len);
1971 /*
1972 * The number of free blocks differs. This mostly
1973 * indicate that the bitmap is corrupt. So exit
1974 * without claiming the space.
1975 */
1976 break;
1977 }
1978 ex.fe_logical = 0xDEADC0DE; /* debug value */
1979 ext4_mb_measure_extent(ac, &ex, e4b);
1980
1981 i += ex.fe_len;
1982 free -= ex.fe_len;
1983 }
1984
1985 ext4_mb_check_limits(ac, e4b, 1);
1986}
1987
1988/*
1989 * This is a special case for storages like raid5
1990 * we try to find stripe-aligned chunks for stripe-size-multiple requests
1991 */
1992static noinline_for_stack
1993void ext4_mb_scan_aligned(struct ext4_allocation_context *ac,
1994 struct ext4_buddy *e4b)
1995{
1996 struct super_block *sb = ac->ac_sb;
1997 struct ext4_sb_info *sbi = EXT4_SB(sb);
1998 void *bitmap = e4b->bd_bitmap;
1999 struct ext4_free_extent ex;
2000 ext4_fsblk_t first_group_block;
2001 ext4_fsblk_t a;
2002 ext4_grpblk_t i;
2003 int max;
2004
2005 BUG_ON(sbi->s_stripe == 0);
2006
2007 /* find first stripe-aligned block in group */
2008 first_group_block = ext4_group_first_block_no(sb, e4b->bd_group);
2009
2010 a = first_group_block + sbi->s_stripe - 1;
2011 do_div(a, sbi->s_stripe);
2012 i = (a * sbi->s_stripe) - first_group_block;
2013
2014 while (i < EXT4_CLUSTERS_PER_GROUP(sb)) {
2015 if (!mb_test_bit(i, bitmap)) {
2016 max = mb_find_extent(e4b, i, sbi->s_stripe, &ex);
2017 if (max >= sbi->s_stripe) {
2018 ac->ac_found++;
2019 ex.fe_logical = 0xDEADF00D; /* debug value */
2020 ac->ac_b_ex = ex;
2021 ext4_mb_use_best_found(ac, e4b);
2022 break;
2023 }
2024 }
2025 i += sbi->s_stripe;
2026 }
2027}
2028
2029/*
2030 * This is now called BEFORE we load the buddy bitmap.
2031 * Returns either 1 or 0 indicating that the group is either suitable
2032 * for the allocation or not. In addition it can also return negative
2033 * error code when something goes wrong.
2034 */
2035static int ext4_mb_good_group(struct ext4_allocation_context *ac,
2036 ext4_group_t group, int cr)
2037{
2038 unsigned free, fragments;
2039 int flex_size = ext4_flex_bg_size(EXT4_SB(ac->ac_sb));
2040 struct ext4_group_info *grp = ext4_get_group_info(ac->ac_sb, group);
2041
2042 BUG_ON(cr < 0 || cr >= 4);
2043
2044 free = grp->bb_free;
2045 if (free == 0)
2046 return 0;
2047 if (cr <= 2 && free < ac->ac_g_ex.fe_len)
2048 return 0;
2049
2050 if (unlikely(EXT4_MB_GRP_BBITMAP_CORRUPT(grp)))
2051 return 0;
2052
2053 /* We only do this if the grp has never been initialized */
2054 if (unlikely(EXT4_MB_GRP_NEED_INIT(grp))) {
2055 int ret = ext4_mb_init_group(ac->ac_sb, group, GFP_NOFS);
2056 if (ret)
2057 return ret;
2058 }
2059
2060 fragments = grp->bb_fragments;
2061 if (fragments == 0)
2062 return 0;
2063
2064 switch (cr) {
2065 case 0:
2066 BUG_ON(ac->ac_2order == 0);
2067
2068 /* Avoid using the first bg of a flexgroup for data files */
2069 if ((ac->ac_flags & EXT4_MB_HINT_DATA) &&
2070 (flex_size >= EXT4_FLEX_SIZE_DIR_ALLOC_SCHEME) &&
2071 ((group % flex_size) == 0))
2072 return 0;
2073
2074 if ((ac->ac_2order > ac->ac_sb->s_blocksize_bits+1) ||
2075 (free / fragments) >= ac->ac_g_ex.fe_len)
2076 return 1;
2077
2078 if (grp->bb_largest_free_order < ac->ac_2order)
2079 return 0;
2080
2081 return 1;
2082 case 1:
2083 if ((free / fragments) >= ac->ac_g_ex.fe_len)
2084 return 1;
2085 break;
2086 case 2:
2087 if (free >= ac->ac_g_ex.fe_len)
2088 return 1;
2089 break;
2090 case 3:
2091 return 1;
2092 default:
2093 BUG();
2094 }
2095
2096 return 0;
2097}
2098
2099static noinline_for_stack int
2100ext4_mb_regular_allocator(struct ext4_allocation_context *ac)
2101{
2102 ext4_group_t ngroups, group, i;
2103 int cr;
2104 int err = 0, first_err = 0;
2105 struct ext4_sb_info *sbi;
2106 struct super_block *sb;
2107 struct ext4_buddy e4b;
2108
2109 sb = ac->ac_sb;
2110 sbi = EXT4_SB(sb);
2111 ngroups = ext4_get_groups_count(sb);
2112 /* non-extent files are limited to low blocks/groups */
2113 if (!(ext4_test_inode_flag(ac->ac_inode, EXT4_INODE_EXTENTS)))
2114 ngroups = sbi->s_blockfile_groups;
2115
2116 BUG_ON(ac->ac_status == AC_STATUS_FOUND);
2117
2118 /* first, try the goal */
2119 err = ext4_mb_find_by_goal(ac, &e4b);
2120 if (err || ac->ac_status == AC_STATUS_FOUND)
2121 goto out;
2122
2123 if (unlikely(ac->ac_flags & EXT4_MB_HINT_GOAL_ONLY))
2124 goto out;
2125
2126 /*
2127 * ac->ac2_order is set only if the fe_len is a power of 2
2128 * if ac2_order is set we also set criteria to 0 so that we
2129 * try exact allocation using buddy.
2130 */
2131 i = fls(ac->ac_g_ex.fe_len);
2132 ac->ac_2order = 0;
2133 /*
2134 * We search using buddy data only if the order of the request
2135 * is greater than equal to the sbi_s_mb_order2_reqs
2136 * You can tune it via /sys/fs/ext4/<partition>/mb_order2_req
2137 */
2138 if (i >= sbi->s_mb_order2_reqs) {
2139 /*
2140 * This should tell if fe_len is exactly power of 2
2141 */
2142 if ((ac->ac_g_ex.fe_len & (~(1 << (i - 1)))) == 0)
2143 ac->ac_2order = i - 1;
2144 }
2145
2146 /* if stream allocation is enabled, use global goal */
2147 if (ac->ac_flags & EXT4_MB_STREAM_ALLOC) {
2148 /* TBD: may be hot point */
2149 spin_lock(&sbi->s_md_lock);
2150 ac->ac_g_ex.fe_group = sbi->s_mb_last_group;
2151 ac->ac_g_ex.fe_start = sbi->s_mb_last_start;
2152 spin_unlock(&sbi->s_md_lock);
2153 }
2154
2155 /* Let's just scan groups to find more-less suitable blocks */
2156 cr = ac->ac_2order ? 0 : 1;
2157 /*
2158 * cr == 0 try to get exact allocation,
2159 * cr == 3 try to get anything
2160 */
2161repeat:
2162 for (; cr < 4 && ac->ac_status == AC_STATUS_CONTINUE; cr++) {
2163 ac->ac_criteria = cr;
2164 /*
2165 * searching for the right group start
2166 * from the goal value specified
2167 */
2168 group = ac->ac_g_ex.fe_group;
2169
2170 for (i = 0; i < ngroups; group++, i++) {
2171 int ret = 0;
2172 cond_resched();
2173 /*
2174 * Artificially restricted ngroups for non-extent
2175 * files makes group > ngroups possible on first loop.
2176 */
2177 if (group >= ngroups)
2178 group = 0;
2179
2180 /* This now checks without needing the buddy page */
2181 ret = ext4_mb_good_group(ac, group, cr);
2182 if (ret <= 0) {
2183 if (!first_err)
2184 first_err = ret;
2185 continue;
2186 }
2187
2188 err = ext4_mb_load_buddy(sb, group, &e4b);
2189 if (err)
2190 goto out;
2191
2192 ext4_lock_group(sb, group);
2193
2194 /*
2195 * We need to check again after locking the
2196 * block group
2197 */
2198 ret = ext4_mb_good_group(ac, group, cr);
2199 if (ret <= 0) {
2200 ext4_unlock_group(sb, group);
2201 ext4_mb_unload_buddy(&e4b);
2202 if (!first_err)
2203 first_err = ret;
2204 continue;
2205 }
2206
2207 ac->ac_groups_scanned++;
2208 if (cr == 0 && ac->ac_2order < sb->s_blocksize_bits+2)
2209 ext4_mb_simple_scan_group(ac, &e4b);
2210 else if (cr == 1 && sbi->s_stripe &&
2211 !(ac->ac_g_ex.fe_len % sbi->s_stripe))
2212 ext4_mb_scan_aligned(ac, &e4b);
2213 else
2214 ext4_mb_complex_scan_group(ac, &e4b);
2215
2216 ext4_unlock_group(sb, group);
2217 ext4_mb_unload_buddy(&e4b);
2218
2219 if (ac->ac_status != AC_STATUS_CONTINUE)
2220 break;
2221 }
2222 }
2223
2224 if (ac->ac_b_ex.fe_len > 0 && ac->ac_status != AC_STATUS_FOUND &&
2225 !(ac->ac_flags & EXT4_MB_HINT_FIRST)) {
2226 /*
2227 * We've been searching too long. Let's try to allocate
2228 * the best chunk we've found so far
2229 */
2230
2231 ext4_mb_try_best_found(ac, &e4b);
2232 if (ac->ac_status != AC_STATUS_FOUND) {
2233 /*
2234 * Someone more lucky has already allocated it.
2235 * The only thing we can do is just take first
2236 * found block(s)
2237 printk(KERN_DEBUG "EXT4-fs: someone won our chunk\n");
2238 */
2239 ac->ac_b_ex.fe_group = 0;
2240 ac->ac_b_ex.fe_start = 0;
2241 ac->ac_b_ex.fe_len = 0;
2242 ac->ac_status = AC_STATUS_CONTINUE;
2243 ac->ac_flags |= EXT4_MB_HINT_FIRST;
2244 cr = 3;
2245 atomic_inc(&sbi->s_mb_lost_chunks);
2246 goto repeat;
2247 }
2248 }
2249out:
2250 if (!err && ac->ac_status != AC_STATUS_FOUND && first_err)
2251 err = first_err;
2252 return err;
2253}
2254
2255static void *ext4_mb_seq_groups_start(struct seq_file *seq, loff_t *pos)
2256{
2257 struct super_block *sb = seq->private;
2258 ext4_group_t group;
2259
2260 if (*pos < 0 || *pos >= ext4_get_groups_count(sb))
2261 return NULL;
2262 group = *pos + 1;
2263 return (void *) ((unsigned long) group);
2264}
2265
2266static void *ext4_mb_seq_groups_next(struct seq_file *seq, void *v, loff_t *pos)
2267{
2268 struct super_block *sb = seq->private;
2269 ext4_group_t group;
2270
2271 ++*pos;
2272 if (*pos < 0 || *pos >= ext4_get_groups_count(sb))
2273 return NULL;
2274 group = *pos + 1;
2275 return (void *) ((unsigned long) group);
2276}
2277
2278static int ext4_mb_seq_groups_show(struct seq_file *seq, void *v)
2279{
2280 struct super_block *sb = seq->private;
2281 ext4_group_t group = (ext4_group_t) ((unsigned long) v);
2282 int i;
2283 int err, buddy_loaded = 0;
2284 struct ext4_buddy e4b;
2285 struct ext4_group_info *grinfo;
2286 struct sg {
2287 struct ext4_group_info info;
2288 ext4_grpblk_t counters[16];
2289 } sg;
2290
2291 group--;
2292 if (group == 0)
2293 seq_puts(seq, "#group: free frags first ["
2294 " 2^0 2^1 2^2 2^3 2^4 2^5 2^6 "
2295 " 2^7 2^8 2^9 2^10 2^11 2^12 2^13 ]\n");
2296
2297 i = (sb->s_blocksize_bits + 2) * sizeof(sg.info.bb_counters[0]) +
2298 sizeof(struct ext4_group_info);
2299 grinfo = ext4_get_group_info(sb, group);
2300 /* Load the group info in memory only if not already loaded. */
2301 if (unlikely(EXT4_MB_GRP_NEED_INIT(grinfo))) {
2302 err = ext4_mb_load_buddy(sb, group, &e4b);
2303 if (err) {
2304 seq_printf(seq, "#%-5u: I/O error\n", group);
2305 return 0;
2306 }
2307 buddy_loaded = 1;
2308 }
2309
2310 memcpy(&sg, ext4_get_group_info(sb, group), i);
2311
2312 if (buddy_loaded)
2313 ext4_mb_unload_buddy(&e4b);
2314
2315 seq_printf(seq, "#%-5u: %-5u %-5u %-5u [", group, sg.info.bb_free,
2316 sg.info.bb_fragments, sg.info.bb_first_free);
2317 for (i = 0; i <= 13; i++)
2318 seq_printf(seq, " %-5u", i <= sb->s_blocksize_bits + 1 ?
2319 sg.info.bb_counters[i] : 0);
2320 seq_printf(seq, " ]\n");
2321
2322 return 0;
2323}
2324
2325static void ext4_mb_seq_groups_stop(struct seq_file *seq, void *v)
2326{
2327}
2328
2329static const struct seq_operations ext4_mb_seq_groups_ops = {
2330 .start = ext4_mb_seq_groups_start,
2331 .next = ext4_mb_seq_groups_next,
2332 .stop = ext4_mb_seq_groups_stop,
2333 .show = ext4_mb_seq_groups_show,
2334};
2335
2336static int ext4_mb_seq_groups_open(struct inode *inode, struct file *file)
2337{
2338 struct super_block *sb = PDE_DATA(inode);
2339 int rc;
2340
2341 rc = seq_open(file, &ext4_mb_seq_groups_ops);
2342 if (rc == 0) {
2343 struct seq_file *m = file->private_data;
2344 m->private = sb;
2345 }
2346 return rc;
2347
2348}
2349
2350const struct file_operations ext4_seq_mb_groups_fops = {
2351 .owner = THIS_MODULE,
2352 .open = ext4_mb_seq_groups_open,
2353 .read = seq_read,
2354 .llseek = seq_lseek,
2355 .release = seq_release,
2356};
2357
2358static struct kmem_cache *get_groupinfo_cache(int blocksize_bits)
2359{
2360 int cache_index = blocksize_bits - EXT4_MIN_BLOCK_LOG_SIZE;
2361 struct kmem_cache *cachep = ext4_groupinfo_caches[cache_index];
2362
2363 BUG_ON(!cachep);
2364 return cachep;
2365}
2366
2367/*
2368 * Allocate the top-level s_group_info array for the specified number
2369 * of groups
2370 */
2371int ext4_mb_alloc_groupinfo(struct super_block *sb, ext4_group_t ngroups)
2372{
2373 struct ext4_sb_info *sbi = EXT4_SB(sb);
2374 unsigned size;
2375 struct ext4_group_info ***new_groupinfo;
2376
2377 size = (ngroups + EXT4_DESC_PER_BLOCK(sb) - 1) >>
2378 EXT4_DESC_PER_BLOCK_BITS(sb);
2379 if (size <= sbi->s_group_info_size)
2380 return 0;
2381
2382 size = roundup_pow_of_two(sizeof(*sbi->s_group_info) * size);
2383 new_groupinfo = ext4_kvzalloc(size, GFP_KERNEL);
2384 if (!new_groupinfo) {
2385 ext4_msg(sb, KERN_ERR, "can't allocate buddy meta group");
2386 return -ENOMEM;
2387 }
2388 if (sbi->s_group_info) {
2389 memcpy(new_groupinfo, sbi->s_group_info,
2390 sbi->s_group_info_size * sizeof(*sbi->s_group_info));
2391 kvfree(sbi->s_group_info);
2392 }
2393 sbi->s_group_info = new_groupinfo;
2394 sbi->s_group_info_size = size / sizeof(*sbi->s_group_info);
2395 ext4_debug("allocated s_groupinfo array for %d meta_bg's\n",
2396 sbi->s_group_info_size);
2397 return 0;
2398}
2399
2400/* Create and initialize ext4_group_info data for the given group. */
2401int ext4_mb_add_groupinfo(struct super_block *sb, ext4_group_t group,
2402 struct ext4_group_desc *desc)
2403{
2404 int i;
2405 int metalen = 0;
2406 struct ext4_sb_info *sbi = EXT4_SB(sb);
2407 struct ext4_group_info **meta_group_info;
2408 struct kmem_cache *cachep = get_groupinfo_cache(sb->s_blocksize_bits);
2409
2410 /*
2411 * First check if this group is the first of a reserved block.
2412 * If it's true, we have to allocate a new table of pointers
2413 * to ext4_group_info structures
2414 */
2415 if (group % EXT4_DESC_PER_BLOCK(sb) == 0) {
2416 metalen = sizeof(*meta_group_info) <<
2417 EXT4_DESC_PER_BLOCK_BITS(sb);
2418 meta_group_info = kmalloc(metalen, GFP_NOFS);
2419 if (meta_group_info == NULL) {
2420 ext4_msg(sb, KERN_ERR, "can't allocate mem "
2421 "for a buddy group");
2422 goto exit_meta_group_info;
2423 }
2424 sbi->s_group_info[group >> EXT4_DESC_PER_BLOCK_BITS(sb)] =
2425 meta_group_info;
2426 }
2427
2428 meta_group_info =
2429 sbi->s_group_info[group >> EXT4_DESC_PER_BLOCK_BITS(sb)];
2430 i = group & (EXT4_DESC_PER_BLOCK(sb) - 1);
2431
2432 meta_group_info[i] = kmem_cache_zalloc(cachep, GFP_NOFS);
2433 if (meta_group_info[i] == NULL) {
2434 ext4_msg(sb, KERN_ERR, "can't allocate buddy mem");
2435 goto exit_group_info;
2436 }
2437 set_bit(EXT4_GROUP_INFO_NEED_INIT_BIT,
2438 &(meta_group_info[i]->bb_state));
2439
2440 /*
2441 * initialize bb_free to be able to skip
2442 * empty groups without initialization
2443 */
2444 if (desc->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) {
2445 meta_group_info[i]->bb_free =
2446 ext4_free_clusters_after_init(sb, group, desc);
2447 } else {
2448 meta_group_info[i]->bb_free =
2449 ext4_free_group_clusters(sb, desc);
2450 }
2451
2452 INIT_LIST_HEAD(&meta_group_info[i]->bb_prealloc_list);
2453 init_rwsem(&meta_group_info[i]->alloc_sem);
2454 meta_group_info[i]->bb_free_root = RB_ROOT;
2455 meta_group_info[i]->bb_largest_free_order = -1; /* uninit */
2456
2457#ifdef DOUBLE_CHECK
2458 {
2459 struct buffer_head *bh;
2460 meta_group_info[i]->bb_bitmap =
2461 kmalloc(sb->s_blocksize, GFP_NOFS);
2462 BUG_ON(meta_group_info[i]->bb_bitmap == NULL);
2463 bh = ext4_read_block_bitmap(sb, group);
2464 BUG_ON(IS_ERR_OR_NULL(bh));
2465 memcpy(meta_group_info[i]->bb_bitmap, bh->b_data,
2466 sb->s_blocksize);
2467 put_bh(bh);
2468 }
2469#endif
2470
2471 return 0;
2472
2473exit_group_info:
2474 /* If a meta_group_info table has been allocated, release it now */
2475 if (group % EXT4_DESC_PER_BLOCK(sb) == 0) {
2476 kfree(sbi->s_group_info[group >> EXT4_DESC_PER_BLOCK_BITS(sb)]);
2477 sbi->s_group_info[group >> EXT4_DESC_PER_BLOCK_BITS(sb)] = NULL;
2478 }
2479exit_meta_group_info:
2480 return -ENOMEM;
2481} /* ext4_mb_add_groupinfo */
2482
2483static int ext4_mb_init_backend(struct super_block *sb)
2484{
2485 ext4_group_t ngroups = ext4_get_groups_count(sb);
2486 ext4_group_t i;
2487 struct ext4_sb_info *sbi = EXT4_SB(sb);
2488 int err;
2489 struct ext4_group_desc *desc;
2490 struct kmem_cache *cachep;
2491
2492 err = ext4_mb_alloc_groupinfo(sb, ngroups);
2493 if (err)
2494 return err;
2495
2496 sbi->s_buddy_cache = new_inode(sb);
2497 if (sbi->s_buddy_cache == NULL) {
2498 ext4_msg(sb, KERN_ERR, "can't get new inode");
2499 goto err_freesgi;
2500 }
2501 /* To avoid potentially colliding with an valid on-disk inode number,
2502 * use EXT4_BAD_INO for the buddy cache inode number. This inode is
2503 * not in the inode hash, so it should never be found by iget(), but
2504 * this will avoid confusion if it ever shows up during debugging. */
2505 sbi->s_buddy_cache->i_ino = EXT4_BAD_INO;
2506 EXT4_I(sbi->s_buddy_cache)->i_disksize = 0;
2507 for (i = 0; i < ngroups; i++) {
2508 desc = ext4_get_group_desc(sb, i, NULL);
2509 if (desc == NULL) {
2510 ext4_msg(sb, KERN_ERR, "can't read descriptor %u", i);
2511 goto err_freebuddy;
2512 }
2513 if (ext4_mb_add_groupinfo(sb, i, desc) != 0)
2514 goto err_freebuddy;
2515 }
2516
2517 return 0;
2518
2519err_freebuddy:
2520 cachep = get_groupinfo_cache(sb->s_blocksize_bits);
2521 while (i-- > 0)
2522 kmem_cache_free(cachep, ext4_get_group_info(sb, i));
2523 i = sbi->s_group_info_size;
2524 while (i-- > 0)
2525 kfree(sbi->s_group_info[i]);
2526 iput(sbi->s_buddy_cache);
2527err_freesgi:
2528 kvfree(sbi->s_group_info);
2529 return -ENOMEM;
2530}
2531
2532static void ext4_groupinfo_destroy_slabs(void)
2533{
2534 int i;
2535
2536 for (i = 0; i < NR_GRPINFO_CACHES; i++) {
2537 if (ext4_groupinfo_caches[i])
2538 kmem_cache_destroy(ext4_groupinfo_caches[i]);
2539 ext4_groupinfo_caches[i] = NULL;
2540 }
2541}
2542
2543static int ext4_groupinfo_create_slab(size_t size)
2544{
2545 static DEFINE_MUTEX(ext4_grpinfo_slab_create_mutex);
2546 int slab_size;
2547 int blocksize_bits = order_base_2(size);
2548 int cache_index = blocksize_bits - EXT4_MIN_BLOCK_LOG_SIZE;
2549 struct kmem_cache *cachep;
2550
2551 if (cache_index >= NR_GRPINFO_CACHES)
2552 return -EINVAL;
2553
2554 if (unlikely(cache_index < 0))
2555 cache_index = 0;
2556
2557 mutex_lock(&ext4_grpinfo_slab_create_mutex);
2558 if (ext4_groupinfo_caches[cache_index]) {
2559 mutex_unlock(&ext4_grpinfo_slab_create_mutex);
2560 return 0; /* Already created */
2561 }
2562
2563 slab_size = offsetof(struct ext4_group_info,
2564 bb_counters[blocksize_bits + 2]);
2565
2566 cachep = kmem_cache_create(ext4_groupinfo_slab_names[cache_index],
2567 slab_size, 0, SLAB_RECLAIM_ACCOUNT,
2568 NULL);
2569
2570 ext4_groupinfo_caches[cache_index] = cachep;
2571
2572 mutex_unlock(&ext4_grpinfo_slab_create_mutex);
2573 if (!cachep) {
2574 printk(KERN_EMERG
2575 "EXT4-fs: no memory for groupinfo slab cache\n");
2576 return -ENOMEM;
2577 }
2578
2579 return 0;
2580}
2581
2582int ext4_mb_init(struct super_block *sb)
2583{
2584 struct ext4_sb_info *sbi = EXT4_SB(sb);
2585 unsigned i, j;
2586 unsigned offset;
2587 unsigned max;
2588 int ret;
2589
2590 i = (sb->s_blocksize_bits + 2) * sizeof(*sbi->s_mb_offsets);
2591
2592 sbi->s_mb_offsets = kmalloc(i, GFP_KERNEL);
2593 if (sbi->s_mb_offsets == NULL) {
2594 ret = -ENOMEM;
2595 goto out;
2596 }
2597
2598 i = (sb->s_blocksize_bits + 2) * sizeof(*sbi->s_mb_maxs);
2599 sbi->s_mb_maxs = kmalloc(i, GFP_KERNEL);
2600 if (sbi->s_mb_maxs == NULL) {
2601 ret = -ENOMEM;
2602 goto out;
2603 }
2604
2605 ret = ext4_groupinfo_create_slab(sb->s_blocksize);
2606 if (ret < 0)
2607 goto out;
2608
2609 /* order 0 is regular bitmap */
2610 sbi->s_mb_maxs[0] = sb->s_blocksize << 3;
2611 sbi->s_mb_offsets[0] = 0;
2612
2613 i = 1;
2614 offset = 0;
2615 max = sb->s_blocksize << 2;
2616 do {
2617 sbi->s_mb_offsets[i] = offset;
2618 sbi->s_mb_maxs[i] = max;
2619 offset += 1 << (sb->s_blocksize_bits - i);
2620 max = max >> 1;
2621 i++;
2622 } while (i <= sb->s_blocksize_bits + 1);
2623
2624 spin_lock_init(&sbi->s_md_lock);
2625 spin_lock_init(&sbi->s_bal_lock);
2626
2627 sbi->s_mb_max_to_scan = MB_DEFAULT_MAX_TO_SCAN;
2628 sbi->s_mb_min_to_scan = MB_DEFAULT_MIN_TO_SCAN;
2629 sbi->s_mb_stats = MB_DEFAULT_STATS;
2630 sbi->s_mb_stream_request = MB_DEFAULT_STREAM_THRESHOLD;
2631 sbi->s_mb_order2_reqs = MB_DEFAULT_ORDER2_REQS;
2632 /*
2633 * The default group preallocation is 512, which for 4k block
2634 * sizes translates to 2 megabytes. However for bigalloc file
2635 * systems, this is probably too big (i.e, if the cluster size
2636 * is 1 megabyte, then group preallocation size becomes half a
2637 * gigabyte!). As a default, we will keep a two megabyte
2638 * group pralloc size for cluster sizes up to 64k, and after
2639 * that, we will force a minimum group preallocation size of
2640 * 32 clusters. This translates to 8 megs when the cluster
2641 * size is 256k, and 32 megs when the cluster size is 1 meg,
2642 * which seems reasonable as a default.
2643 */
2644 sbi->s_mb_group_prealloc = max(MB_DEFAULT_GROUP_PREALLOC >>
2645 sbi->s_cluster_bits, 32);
2646 /*
2647 * If there is a s_stripe > 1, then we set the s_mb_group_prealloc
2648 * to the lowest multiple of s_stripe which is bigger than
2649 * the s_mb_group_prealloc as determined above. We want
2650 * the preallocation size to be an exact multiple of the
2651 * RAID stripe size so that preallocations don't fragment
2652 * the stripes.
2653 */
2654 if (sbi->s_stripe > 1) {
2655 sbi->s_mb_group_prealloc = roundup(
2656 sbi->s_mb_group_prealloc, sbi->s_stripe);
2657 }
2658
2659 sbi->s_locality_groups = alloc_percpu(struct ext4_locality_group);
2660 if (sbi->s_locality_groups == NULL) {
2661 ret = -ENOMEM;
2662 goto out;
2663 }
2664 for_each_possible_cpu(i) {
2665 struct ext4_locality_group *lg;
2666 lg = per_cpu_ptr(sbi->s_locality_groups, i);
2667 mutex_init(&lg->lg_mutex);
2668 for (j = 0; j < PREALLOC_TB_SIZE; j++)
2669 INIT_LIST_HEAD(&lg->lg_prealloc_list[j]);
2670 spin_lock_init(&lg->lg_prealloc_lock);
2671 }
2672
2673 /* init file for buddy data */
2674 ret = ext4_mb_init_backend(sb);
2675 if (ret != 0)
2676 goto out_free_locality_groups;
2677
2678 return 0;
2679
2680out_free_locality_groups:
2681 free_percpu(sbi->s_locality_groups);
2682 sbi->s_locality_groups = NULL;
2683out:
2684 kfree(sbi->s_mb_offsets);
2685 sbi->s_mb_offsets = NULL;
2686 kfree(sbi->s_mb_maxs);
2687 sbi->s_mb_maxs = NULL;
2688 return ret;
2689}
2690
2691/* need to called with the ext4 group lock held */
2692static void ext4_mb_cleanup_pa(struct ext4_group_info *grp)
2693{
2694 struct ext4_prealloc_space *pa;
2695 struct list_head *cur, *tmp;
2696 int count = 0;
2697
2698 list_for_each_safe(cur, tmp, &grp->bb_prealloc_list) {
2699 pa = list_entry(cur, struct ext4_prealloc_space, pa_group_list);
2700 list_del(&pa->pa_group_list);
2701 count++;
2702 kmem_cache_free(ext4_pspace_cachep, pa);
2703 }
2704 if (count)
2705 mb_debug(1, "mballoc: %u PAs left\n", count);
2706
2707}
2708
2709int ext4_mb_release(struct super_block *sb)
2710{
2711 ext4_group_t ngroups = ext4_get_groups_count(sb);
2712 ext4_group_t i;
2713 int num_meta_group_infos;
2714 struct ext4_group_info *grinfo;
2715 struct ext4_sb_info *sbi = EXT4_SB(sb);
2716 struct kmem_cache *cachep = get_groupinfo_cache(sb->s_blocksize_bits);
2717
2718 if (sbi->s_group_info) {
2719 for (i = 0; i < ngroups; i++) {
2720 grinfo = ext4_get_group_info(sb, i);
2721#ifdef DOUBLE_CHECK
2722 kfree(grinfo->bb_bitmap);
2723#endif
2724 ext4_lock_group(sb, i);
2725 ext4_mb_cleanup_pa(grinfo);
2726 ext4_unlock_group(sb, i);
2727 kmem_cache_free(cachep, grinfo);
2728 }
2729 num_meta_group_infos = (ngroups +
2730 EXT4_DESC_PER_BLOCK(sb) - 1) >>
2731 EXT4_DESC_PER_BLOCK_BITS(sb);
2732 for (i = 0; i < num_meta_group_infos; i++)
2733 kfree(sbi->s_group_info[i]);
2734 kvfree(sbi->s_group_info);
2735 }
2736 kfree(sbi->s_mb_offsets);
2737 kfree(sbi->s_mb_maxs);
2738 iput(sbi->s_buddy_cache);
2739 if (sbi->s_mb_stats) {
2740 ext4_msg(sb, KERN_INFO,
2741 "mballoc: %u blocks %u reqs (%u success)",
2742 atomic_read(&sbi->s_bal_allocated),
2743 atomic_read(&sbi->s_bal_reqs),
2744 atomic_read(&sbi->s_bal_success));
2745 ext4_msg(sb, KERN_INFO,
2746 "mballoc: %u extents scanned, %u goal hits, "
2747 "%u 2^N hits, %u breaks, %u lost",
2748 atomic_read(&sbi->s_bal_ex_scanned),
2749 atomic_read(&sbi->s_bal_goals),
2750 atomic_read(&sbi->s_bal_2orders),
2751 atomic_read(&sbi->s_bal_breaks),
2752 atomic_read(&sbi->s_mb_lost_chunks));
2753 ext4_msg(sb, KERN_INFO,
2754 "mballoc: %lu generated and it took %Lu",
2755 sbi->s_mb_buddies_generated,
2756 sbi->s_mb_generation_time);
2757 ext4_msg(sb, KERN_INFO,
2758 "mballoc: %u preallocated, %u discarded",
2759 atomic_read(&sbi->s_mb_preallocated),
2760 atomic_read(&sbi->s_mb_discarded));
2761 }
2762
2763 free_percpu(sbi->s_locality_groups);
2764
2765 return 0;
2766}
2767
2768static inline int ext4_issue_discard(struct super_block *sb,
2769 ext4_group_t block_group, ext4_grpblk_t cluster, int count)
2770{
2771 ext4_fsblk_t discard_block;
2772
2773 discard_block = (EXT4_C2B(EXT4_SB(sb), cluster) +
2774 ext4_group_first_block_no(sb, block_group));
2775 count = EXT4_C2B(EXT4_SB(sb), count);
2776 trace_ext4_discard_blocks(sb,
2777 (unsigned long long) discard_block, count);
2778 return sb_issue_discard(sb, discard_block, count, GFP_NOFS, 0);
2779}
2780
2781/*
2782 * This function is called by the jbd2 layer once the commit has finished,
2783 * so we know we can free the blocks that were released with that commit.
2784 */
2785static void ext4_free_data_callback(struct super_block *sb,
2786 struct ext4_journal_cb_entry *jce,
2787 int rc)
2788{
2789 struct ext4_free_data *entry = (struct ext4_free_data *)jce;
2790 struct ext4_buddy e4b;
2791 struct ext4_group_info *db;
2792 int err, count = 0, count2 = 0;
2793
2794 mb_debug(1, "gonna free %u blocks in group %u (0x%p):",
2795 entry->efd_count, entry->efd_group, entry);
2796
2797 if (test_opt(sb, DISCARD)) {
2798 err = ext4_issue_discard(sb, entry->efd_group,
2799 entry->efd_start_cluster,
2800 entry->efd_count);
2801 if (err && err != -EOPNOTSUPP)
2802 ext4_msg(sb, KERN_WARNING, "discard request in"
2803 " group:%d block:%d count:%d failed"
2804 " with %d", entry->efd_group,
2805 entry->efd_start_cluster,
2806 entry->efd_count, err);
2807 }
2808
2809 err = ext4_mb_load_buddy(sb, entry->efd_group, &e4b);
2810 /* we expect to find existing buddy because it's pinned */
2811 BUG_ON(err != 0);
2812
2813
2814 db = e4b.bd_info;
2815 /* there are blocks to put in buddy to make them really free */
2816 count += entry->efd_count;
2817 count2++;
2818 ext4_lock_group(sb, entry->efd_group);
2819 /* Take it out of per group rb tree */
2820 rb_erase(&entry->efd_node, &(db->bb_free_root));
2821 mb_free_blocks(NULL, &e4b, entry->efd_start_cluster, entry->efd_count);
2822
2823 /*
2824 * Clear the trimmed flag for the group so that the next
2825 * ext4_trim_fs can trim it.
2826 * If the volume is mounted with -o discard, online discard
2827 * is supported and the free blocks will be trimmed online.
2828 */
2829 if (!test_opt(sb, DISCARD))
2830 EXT4_MB_GRP_CLEAR_TRIMMED(db);
2831
2832 if (!db->bb_free_root.rb_node) {
2833 /* No more items in the per group rb tree
2834 * balance refcounts from ext4_mb_free_metadata()
2835 */
2836 put_page(e4b.bd_buddy_page);
2837 put_page(e4b.bd_bitmap_page);
2838 }
2839 ext4_unlock_group(sb, entry->efd_group);
2840 kmem_cache_free(ext4_free_data_cachep, entry);
2841 ext4_mb_unload_buddy(&e4b);
2842
2843 mb_debug(1, "freed %u blocks in %u structures\n", count, count2);
2844}
2845
2846int __init ext4_init_mballoc(void)
2847{
2848 ext4_pspace_cachep = KMEM_CACHE(ext4_prealloc_space,
2849 SLAB_RECLAIM_ACCOUNT);
2850 if (ext4_pspace_cachep == NULL)
2851 return -ENOMEM;
2852
2853 ext4_ac_cachep = KMEM_CACHE(ext4_allocation_context,
2854 SLAB_RECLAIM_ACCOUNT);
2855 if (ext4_ac_cachep == NULL) {
2856 kmem_cache_destroy(ext4_pspace_cachep);
2857 return -ENOMEM;
2858 }
2859
2860 ext4_free_data_cachep = KMEM_CACHE(ext4_free_data,
2861 SLAB_RECLAIM_ACCOUNT);
2862 if (ext4_free_data_cachep == NULL) {
2863 kmem_cache_destroy(ext4_pspace_cachep);
2864 kmem_cache_destroy(ext4_ac_cachep);
2865 return -ENOMEM;
2866 }
2867 return 0;
2868}
2869
2870void ext4_exit_mballoc(void)
2871{
2872 /*
2873 * Wait for completion of call_rcu()'s on ext4_pspace_cachep
2874 * before destroying the slab cache.
2875 */
2876 rcu_barrier();
2877 kmem_cache_destroy(ext4_pspace_cachep);
2878 kmem_cache_destroy(ext4_ac_cachep);
2879 kmem_cache_destroy(ext4_free_data_cachep);
2880 ext4_groupinfo_destroy_slabs();
2881}
2882
2883
2884/*
2885 * Check quota and mark chosen space (ac->ac_b_ex) non-free in bitmaps
2886 * Returns 0 if success or error code
2887 */
2888static noinline_for_stack int
2889ext4_mb_mark_diskspace_used(struct ext4_allocation_context *ac,
2890 handle_t *handle, unsigned int reserv_clstrs)
2891{
2892 struct buffer_head *bitmap_bh = NULL;
2893 struct ext4_group_desc *gdp;
2894 struct buffer_head *gdp_bh;
2895 struct ext4_sb_info *sbi;
2896 struct super_block *sb;
2897 ext4_fsblk_t block;
2898 int err, len;
2899
2900 BUG_ON(ac->ac_status != AC_STATUS_FOUND);
2901 BUG_ON(ac->ac_b_ex.fe_len <= 0);
2902
2903 sb = ac->ac_sb;
2904 sbi = EXT4_SB(sb);
2905
2906 bitmap_bh = ext4_read_block_bitmap(sb, ac->ac_b_ex.fe_group);
2907 if (IS_ERR(bitmap_bh)) {
2908 err = PTR_ERR(bitmap_bh);
2909 bitmap_bh = NULL;
2910 goto out_err;
2911 }
2912
2913 BUFFER_TRACE(bitmap_bh, "getting write access");
2914 err = ext4_journal_get_write_access(handle, bitmap_bh);
2915 if (err)
2916 goto out_err;
2917
2918 err = -EIO;
2919 gdp = ext4_get_group_desc(sb, ac->ac_b_ex.fe_group, &gdp_bh);
2920 if (!gdp)
2921 goto out_err;
2922
2923 ext4_debug("using block group %u(%d)\n", ac->ac_b_ex.fe_group,
2924 ext4_free_group_clusters(sb, gdp));
2925
2926 BUFFER_TRACE(gdp_bh, "get_write_access");
2927 err = ext4_journal_get_write_access(handle, gdp_bh);
2928 if (err)
2929 goto out_err;
2930
2931 block = ext4_grp_offs_to_block(sb, &ac->ac_b_ex);
2932
2933 len = EXT4_C2B(sbi, ac->ac_b_ex.fe_len);
2934 if (!ext4_data_block_valid(sbi, block, len)) {
2935 ext4_error(sb, "Allocating blocks %llu-%llu which overlap "
2936 "fs metadata", block, block+len);
2937 /* File system mounted not to panic on error
2938 * Fix the bitmap and repeat the block allocation
2939 * We leak some of the blocks here.
2940 */
2941 ext4_lock_group(sb, ac->ac_b_ex.fe_group);
2942 ext4_set_bits(bitmap_bh->b_data, ac->ac_b_ex.fe_start,
2943 ac->ac_b_ex.fe_len);
2944 ext4_unlock_group(sb, ac->ac_b_ex.fe_group);
2945 err = ext4_handle_dirty_metadata(handle, NULL, bitmap_bh);
2946 if (!err)
2947 err = -EAGAIN;
2948 goto out_err;
2949 }
2950
2951 ext4_lock_group(sb, ac->ac_b_ex.fe_group);
2952#ifdef AGGRESSIVE_CHECK
2953 {
2954 int i;
2955 for (i = 0; i < ac->ac_b_ex.fe_len; i++) {
2956 BUG_ON(mb_test_bit(ac->ac_b_ex.fe_start + i,
2957 bitmap_bh->b_data));
2958 }
2959 }
2960#endif
2961 ext4_set_bits(bitmap_bh->b_data, ac->ac_b_ex.fe_start,
2962 ac->ac_b_ex.fe_len);
2963 if (gdp->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) {
2964 gdp->bg_flags &= cpu_to_le16(~EXT4_BG_BLOCK_UNINIT);
2965 ext4_free_group_clusters_set(sb, gdp,
2966 ext4_free_clusters_after_init(sb,
2967 ac->ac_b_ex.fe_group, gdp));
2968 }
2969 len = ext4_free_group_clusters(sb, gdp) - ac->ac_b_ex.fe_len;
2970 ext4_free_group_clusters_set(sb, gdp, len);
2971 ext4_block_bitmap_csum_set(sb, ac->ac_b_ex.fe_group, gdp, bitmap_bh);
2972 ext4_group_desc_csum_set(sb, ac->ac_b_ex.fe_group, gdp);
2973
2974 ext4_unlock_group(sb, ac->ac_b_ex.fe_group);
2975 percpu_counter_sub(&sbi->s_freeclusters_counter, ac->ac_b_ex.fe_len);
2976 /*
2977 * Now reduce the dirty block count also. Should not go negative
2978 */
2979 if (!(ac->ac_flags & EXT4_MB_DELALLOC_RESERVED))
2980 /* release all the reserved blocks if non delalloc */
2981 percpu_counter_sub(&sbi->s_dirtyclusters_counter,
2982 reserv_clstrs);
2983
2984 if (sbi->s_log_groups_per_flex) {
2985 ext4_group_t flex_group = ext4_flex_group(sbi,
2986 ac->ac_b_ex.fe_group);
2987 atomic64_sub(ac->ac_b_ex.fe_len,
2988 &sbi->s_flex_groups[flex_group].free_clusters);
2989 }
2990
2991 err = ext4_handle_dirty_metadata(handle, NULL, bitmap_bh);
2992 if (err)
2993 goto out_err;
2994 err = ext4_handle_dirty_metadata(handle, NULL, gdp_bh);
2995
2996out_err:
2997 brelse(bitmap_bh);
2998 return err;
2999}
3000
3001/*
3002 * here we normalize request for locality group
3003 * Group request are normalized to s_mb_group_prealloc, which goes to
3004 * s_strip if we set the same via mount option.
3005 * s_mb_group_prealloc can be configured via
3006 * /sys/fs/ext4/<partition>/mb_group_prealloc
3007 *
3008 * XXX: should we try to preallocate more than the group has now?
3009 */
3010static void ext4_mb_normalize_group_request(struct ext4_allocation_context *ac)
3011{
3012 struct super_block *sb = ac->ac_sb;
3013 struct ext4_locality_group *lg = ac->ac_lg;
3014
3015 BUG_ON(lg == NULL);
3016 ac->ac_g_ex.fe_len = EXT4_SB(sb)->s_mb_group_prealloc;
3017 mb_debug(1, "#%u: goal %u blocks for locality group\n",
3018 current->pid, ac->ac_g_ex.fe_len);
3019}
3020
3021/*
3022 * Normalization means making request better in terms of
3023 * size and alignment
3024 */
3025static noinline_for_stack void
3026ext4_mb_normalize_request(struct ext4_allocation_context *ac,
3027 struct ext4_allocation_request *ar)
3028{
3029 struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
3030 int bsbits, max;
3031 ext4_lblk_t end;
3032 loff_t size, start_off;
3033 loff_t orig_size __maybe_unused;
3034 ext4_lblk_t start;
3035 struct ext4_inode_info *ei = EXT4_I(ac->ac_inode);
3036 struct ext4_prealloc_space *pa;
3037
3038 /* do normalize only data requests, metadata requests
3039 do not need preallocation */
3040 if (!(ac->ac_flags & EXT4_MB_HINT_DATA))
3041 return;
3042
3043 /* sometime caller may want exact blocks */
3044 if (unlikely(ac->ac_flags & EXT4_MB_HINT_GOAL_ONLY))
3045 return;
3046
3047 /* caller may indicate that preallocation isn't
3048 * required (it's a tail, for example) */
3049 if (ac->ac_flags & EXT4_MB_HINT_NOPREALLOC)
3050 return;
3051
3052 if (ac->ac_flags & EXT4_MB_HINT_GROUP_ALLOC) {
3053 ext4_mb_normalize_group_request(ac);
3054 return ;
3055 }
3056
3057 bsbits = ac->ac_sb->s_blocksize_bits;
3058
3059 /* first, let's learn actual file size
3060 * given current request is allocated */
3061 size = ac->ac_o_ex.fe_logical + EXT4_C2B(sbi, ac->ac_o_ex.fe_len);
3062 size = size << bsbits;
3063 if (size < i_size_read(ac->ac_inode))
3064 size = i_size_read(ac->ac_inode);
3065 orig_size = size;
3066
3067 /* max size of free chunks */
3068 max = 2 << bsbits;
3069
3070#define NRL_CHECK_SIZE(req, size, max, chunk_size) \
3071 (req <= (size) || max <= (chunk_size))
3072
3073 /* first, try to predict filesize */
3074 /* XXX: should this table be tunable? */
3075 start_off = 0;
3076 if (size <= 16 * 1024) {
3077 size = 16 * 1024;
3078 } else if (size <= 32 * 1024) {
3079 size = 32 * 1024;
3080 } else if (size <= 64 * 1024) {
3081 size = 64 * 1024;
3082 } else if (size <= 128 * 1024) {
3083 size = 128 * 1024;
3084 } else if (size <= 256 * 1024) {
3085 size = 256 * 1024;
3086 } else if (size <= 512 * 1024) {
3087 size = 512 * 1024;
3088 } else if (size <= 1024 * 1024) {
3089 size = 1024 * 1024;
3090 } else if (NRL_CHECK_SIZE(size, 4 * 1024 * 1024, max, 2 * 1024)) {
3091 start_off = ((loff_t)ac->ac_o_ex.fe_logical >>
3092 (21 - bsbits)) << 21;
3093 size = 2 * 1024 * 1024;
3094 } else if (NRL_CHECK_SIZE(size, 8 * 1024 * 1024, max, 4 * 1024)) {
3095 start_off = ((loff_t)ac->ac_o_ex.fe_logical >>
3096 (22 - bsbits)) << 22;
3097 size = 4 * 1024 * 1024;
3098 } else if (NRL_CHECK_SIZE(ac->ac_o_ex.fe_len,
3099 (8<<20)>>bsbits, max, 8 * 1024)) {
3100 start_off = ((loff_t)ac->ac_o_ex.fe_logical >>
3101 (23 - bsbits)) << 23;
3102 size = 8 * 1024 * 1024;
3103 } else {
3104 start_off = (loff_t) ac->ac_o_ex.fe_logical << bsbits;
3105 size = (loff_t) EXT4_C2B(EXT4_SB(ac->ac_sb),
3106 ac->ac_o_ex.fe_len) << bsbits;
3107 }
3108 size = size >> bsbits;
3109 start = start_off >> bsbits;
3110
3111 /* don't cover already allocated blocks in selected range */
3112 if (ar->pleft && start <= ar->lleft) {
3113 size -= ar->lleft + 1 - start;
3114 start = ar->lleft + 1;
3115 }
3116 if (ar->pright && start + size - 1 >= ar->lright)
3117 size -= start + size - ar->lright;
3118
3119 end = start + size;
3120
3121 /* check we don't cross already preallocated blocks */
3122 rcu_read_lock();
3123 list_for_each_entry_rcu(pa, &ei->i_prealloc_list, pa_inode_list) {
3124 ext4_lblk_t pa_end;
3125
3126 if (pa->pa_deleted)
3127 continue;
3128 spin_lock(&pa->pa_lock);
3129 if (pa->pa_deleted) {
3130 spin_unlock(&pa->pa_lock);
3131 continue;
3132 }
3133
3134 pa_end = pa->pa_lstart + EXT4_C2B(EXT4_SB(ac->ac_sb),
3135 pa->pa_len);
3136
3137 /* PA must not overlap original request */
3138 BUG_ON(!(ac->ac_o_ex.fe_logical >= pa_end ||
3139 ac->ac_o_ex.fe_logical < pa->pa_lstart));
3140
3141 /* skip PAs this normalized request doesn't overlap with */
3142 if (pa->pa_lstart >= end || pa_end <= start) {
3143 spin_unlock(&pa->pa_lock);
3144 continue;
3145 }
3146 BUG_ON(pa->pa_lstart <= start && pa_end >= end);
3147
3148 /* adjust start or end to be adjacent to this pa */
3149 if (pa_end <= ac->ac_o_ex.fe_logical) {
3150 BUG_ON(pa_end < start);
3151 start = pa_end;
3152 } else if (pa->pa_lstart > ac->ac_o_ex.fe_logical) {
3153 BUG_ON(pa->pa_lstart > end);
3154 end = pa->pa_lstart;
3155 }
3156 spin_unlock(&pa->pa_lock);
3157 }
3158 rcu_read_unlock();
3159 size = end - start;
3160
3161 /* XXX: extra loop to check we really don't overlap preallocations */
3162 rcu_read_lock();
3163 list_for_each_entry_rcu(pa, &ei->i_prealloc_list, pa_inode_list) {
3164 ext4_lblk_t pa_end;
3165
3166 spin_lock(&pa->pa_lock);
3167 if (pa->pa_deleted == 0) {
3168 pa_end = pa->pa_lstart + EXT4_C2B(EXT4_SB(ac->ac_sb),
3169 pa->pa_len);
3170 BUG_ON(!(start >= pa_end || end <= pa->pa_lstart));
3171 }
3172 spin_unlock(&pa->pa_lock);
3173 }
3174 rcu_read_unlock();
3175
3176 if (start + size <= ac->ac_o_ex.fe_logical &&
3177 start > ac->ac_o_ex.fe_logical) {
3178 ext4_msg(ac->ac_sb, KERN_ERR,
3179 "start %lu, size %lu, fe_logical %lu",
3180 (unsigned long) start, (unsigned long) size,
3181 (unsigned long) ac->ac_o_ex.fe_logical);
3182 BUG();
3183 }
3184 BUG_ON(size <= 0 || size > EXT4_BLOCKS_PER_GROUP(ac->ac_sb));
3185
3186 /* now prepare goal request */
3187
3188 /* XXX: is it better to align blocks WRT to logical
3189 * placement or satisfy big request as is */
3190 ac->ac_g_ex.fe_logical = start;
3191 ac->ac_g_ex.fe_len = EXT4_NUM_B2C(sbi, size);
3192
3193 /* define goal start in order to merge */
3194 if (ar->pright && (ar->lright == (start + size))) {
3195 /* merge to the right */
3196 ext4_get_group_no_and_offset(ac->ac_sb, ar->pright - size,
3197 &ac->ac_f_ex.fe_group,
3198 &ac->ac_f_ex.fe_start);
3199 ac->ac_flags |= EXT4_MB_HINT_TRY_GOAL;
3200 }
3201 if (ar->pleft && (ar->lleft + 1 == start)) {
3202 /* merge to the left */
3203 ext4_get_group_no_and_offset(ac->ac_sb, ar->pleft + 1,
3204 &ac->ac_f_ex.fe_group,
3205 &ac->ac_f_ex.fe_start);
3206 ac->ac_flags |= EXT4_MB_HINT_TRY_GOAL;
3207 }
3208
3209 mb_debug(1, "goal: %u(was %u) blocks at %u\n", (unsigned) size,
3210 (unsigned) orig_size, (unsigned) start);
3211}
3212
3213static void ext4_mb_collect_stats(struct ext4_allocation_context *ac)
3214{
3215 struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
3216
3217 if (sbi->s_mb_stats && ac->ac_g_ex.fe_len > 1) {
3218 atomic_inc(&sbi->s_bal_reqs);
3219 atomic_add(ac->ac_b_ex.fe_len, &sbi->s_bal_allocated);
3220 if (ac->ac_b_ex.fe_len >= ac->ac_o_ex.fe_len)
3221 atomic_inc(&sbi->s_bal_success);
3222 atomic_add(ac->ac_found, &sbi->s_bal_ex_scanned);
3223 if (ac->ac_g_ex.fe_start == ac->ac_b_ex.fe_start &&
3224 ac->ac_g_ex.fe_group == ac->ac_b_ex.fe_group)
3225 atomic_inc(&sbi->s_bal_goals);
3226 if (ac->ac_found > sbi->s_mb_max_to_scan)
3227 atomic_inc(&sbi->s_bal_breaks);
3228 }
3229
3230 if (ac->ac_op == EXT4_MB_HISTORY_ALLOC)
3231 trace_ext4_mballoc_alloc(ac);
3232 else
3233 trace_ext4_mballoc_prealloc(ac);
3234}
3235
3236/*
3237 * Called on failure; free up any blocks from the inode PA for this
3238 * context. We don't need this for MB_GROUP_PA because we only change
3239 * pa_free in ext4_mb_release_context(), but on failure, we've already
3240 * zeroed out ac->ac_b_ex.fe_len, so group_pa->pa_free is not changed.
3241 */
3242static void ext4_discard_allocated_blocks(struct ext4_allocation_context *ac)
3243{
3244 struct ext4_prealloc_space *pa = ac->ac_pa;
3245 struct ext4_buddy e4b;
3246 int err;
3247
3248 if (pa == NULL) {
3249 if (ac->ac_f_ex.fe_len == 0)
3250 return;
3251 err = ext4_mb_load_buddy(ac->ac_sb, ac->ac_f_ex.fe_group, &e4b);
3252 if (err) {
3253 /*
3254 * This should never happen since we pin the
3255 * pages in the ext4_allocation_context so
3256 * ext4_mb_load_buddy() should never fail.
3257 */
3258 WARN(1, "mb_load_buddy failed (%d)", err);
3259 return;
3260 }
3261 ext4_lock_group(ac->ac_sb, ac->ac_f_ex.fe_group);
3262 mb_free_blocks(ac->ac_inode, &e4b, ac->ac_f_ex.fe_start,
3263 ac->ac_f_ex.fe_len);
3264 ext4_unlock_group(ac->ac_sb, ac->ac_f_ex.fe_group);
3265 ext4_mb_unload_buddy(&e4b);
3266 return;
3267 }
3268 if (pa->pa_type == MB_INODE_PA)
3269 pa->pa_free += ac->ac_b_ex.fe_len;
3270}
3271
3272/*
3273 * use blocks preallocated to inode
3274 */
3275static void ext4_mb_use_inode_pa(struct ext4_allocation_context *ac,
3276 struct ext4_prealloc_space *pa)
3277{
3278 struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
3279 ext4_fsblk_t start;
3280 ext4_fsblk_t end;
3281 int len;
3282
3283 /* found preallocated blocks, use them */
3284 start = pa->pa_pstart + (ac->ac_o_ex.fe_logical - pa->pa_lstart);
3285 end = min(pa->pa_pstart + EXT4_C2B(sbi, pa->pa_len),
3286 start + EXT4_C2B(sbi, ac->ac_o_ex.fe_len));
3287 len = EXT4_NUM_B2C(sbi, end - start);
3288 ext4_get_group_no_and_offset(ac->ac_sb, start, &ac->ac_b_ex.fe_group,
3289 &ac->ac_b_ex.fe_start);
3290 ac->ac_b_ex.fe_len = len;
3291 ac->ac_status = AC_STATUS_FOUND;
3292 ac->ac_pa = pa;
3293
3294 BUG_ON(start < pa->pa_pstart);
3295 BUG_ON(end > pa->pa_pstart + EXT4_C2B(sbi, pa->pa_len));
3296 BUG_ON(pa->pa_free < len);
3297 pa->pa_free -= len;
3298
3299 mb_debug(1, "use %llu/%u from inode pa %p\n", start, len, pa);
3300}
3301
3302/*
3303 * use blocks preallocated to locality group
3304 */
3305static void ext4_mb_use_group_pa(struct ext4_allocation_context *ac,
3306 struct ext4_prealloc_space *pa)
3307{
3308 unsigned int len = ac->ac_o_ex.fe_len;
3309
3310 ext4_get_group_no_and_offset(ac->ac_sb, pa->pa_pstart,
3311 &ac->ac_b_ex.fe_group,
3312 &ac->ac_b_ex.fe_start);
3313 ac->ac_b_ex.fe_len = len;
3314 ac->ac_status = AC_STATUS_FOUND;
3315 ac->ac_pa = pa;
3316
3317 /* we don't correct pa_pstart or pa_plen here to avoid
3318 * possible race when the group is being loaded concurrently
3319 * instead we correct pa later, after blocks are marked
3320 * in on-disk bitmap -- see ext4_mb_release_context()
3321 * Other CPUs are prevented from allocating from this pa by lg_mutex
3322 */
3323 mb_debug(1, "use %u/%u from group pa %p\n", pa->pa_lstart-len, len, pa);
3324}
3325
3326/*
3327 * Return the prealloc space that have minimal distance
3328 * from the goal block. @cpa is the prealloc
3329 * space that is having currently known minimal distance
3330 * from the goal block.
3331 */
3332static struct ext4_prealloc_space *
3333ext4_mb_check_group_pa(ext4_fsblk_t goal_block,
3334 struct ext4_prealloc_space *pa,
3335 struct ext4_prealloc_space *cpa)
3336{
3337 ext4_fsblk_t cur_distance, new_distance;
3338
3339 if (cpa == NULL) {
3340 atomic_inc(&pa->pa_count);
3341 return pa;
3342 }
3343 cur_distance = abs(goal_block - cpa->pa_pstart);
3344 new_distance = abs(goal_block - pa->pa_pstart);
3345
3346 if (cur_distance <= new_distance)
3347 return cpa;
3348
3349 /* drop the previous reference */
3350 atomic_dec(&cpa->pa_count);
3351 atomic_inc(&pa->pa_count);
3352 return pa;
3353}
3354
3355/*
3356 * search goal blocks in preallocated space
3357 */
3358static noinline_for_stack int
3359ext4_mb_use_preallocated(struct ext4_allocation_context *ac)
3360{
3361 struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
3362 int order, i;
3363 struct ext4_inode_info *ei = EXT4_I(ac->ac_inode);
3364 struct ext4_locality_group *lg;
3365 struct ext4_prealloc_space *pa, *cpa = NULL;
3366 ext4_fsblk_t goal_block;
3367
3368 /* only data can be preallocated */
3369 if (!(ac->ac_flags & EXT4_MB_HINT_DATA))
3370 return 0;
3371
3372 /* first, try per-file preallocation */
3373 rcu_read_lock();
3374 list_for_each_entry_rcu(pa, &ei->i_prealloc_list, pa_inode_list) {
3375
3376 /* all fields in this condition don't change,
3377 * so we can skip locking for them */
3378 if (ac->ac_o_ex.fe_logical < pa->pa_lstart ||
3379 ac->ac_o_ex.fe_logical >= (pa->pa_lstart +
3380 EXT4_C2B(sbi, pa->pa_len)))
3381 continue;
3382
3383 /* non-extent files can't have physical blocks past 2^32 */
3384 if (!(ext4_test_inode_flag(ac->ac_inode, EXT4_INODE_EXTENTS)) &&
3385 (pa->pa_pstart + EXT4_C2B(sbi, pa->pa_len) >
3386 EXT4_MAX_BLOCK_FILE_PHYS))
3387 continue;
3388
3389 /* found preallocated blocks, use them */
3390 spin_lock(&pa->pa_lock);
3391 if (pa->pa_deleted == 0 && pa->pa_free) {
3392 atomic_inc(&pa->pa_count);
3393 ext4_mb_use_inode_pa(ac, pa);
3394 spin_unlock(&pa->pa_lock);
3395 ac->ac_criteria = 10;
3396 rcu_read_unlock();
3397 return 1;
3398 }
3399 spin_unlock(&pa->pa_lock);
3400 }
3401 rcu_read_unlock();
3402
3403 /* can we use group allocation? */
3404 if (!(ac->ac_flags & EXT4_MB_HINT_GROUP_ALLOC))
3405 return 0;
3406
3407 /* inode may have no locality group for some reason */
3408 lg = ac->ac_lg;
3409 if (lg == NULL)
3410 return 0;
3411 order = fls(ac->ac_o_ex.fe_len) - 1;
3412 if (order > PREALLOC_TB_SIZE - 1)
3413 /* The max size of hash table is PREALLOC_TB_SIZE */
3414 order = PREALLOC_TB_SIZE - 1;
3415
3416 goal_block = ext4_grp_offs_to_block(ac->ac_sb, &ac->ac_g_ex);
3417 /*
3418 * search for the prealloc space that is having
3419 * minimal distance from the goal block.
3420 */
3421 for (i = order; i < PREALLOC_TB_SIZE; i++) {
3422 rcu_read_lock();
3423 list_for_each_entry_rcu(pa, &lg->lg_prealloc_list[i],
3424 pa_inode_list) {
3425 spin_lock(&pa->pa_lock);
3426 if (pa->pa_deleted == 0 &&
3427 pa->pa_free >= ac->ac_o_ex.fe_len) {
3428
3429 cpa = ext4_mb_check_group_pa(goal_block,
3430 pa, cpa);
3431 }
3432 spin_unlock(&pa->pa_lock);
3433 }
3434 rcu_read_unlock();
3435 }
3436 if (cpa) {
3437 ext4_mb_use_group_pa(ac, cpa);
3438 ac->ac_criteria = 20;
3439 return 1;
3440 }
3441 return 0;
3442}
3443
3444/*
3445 * the function goes through all block freed in the group
3446 * but not yet committed and marks them used in in-core bitmap.
3447 * buddy must be generated from this bitmap
3448 * Need to be called with the ext4 group lock held
3449 */
3450static void ext4_mb_generate_from_freelist(struct super_block *sb, void *bitmap,
3451 ext4_group_t group)
3452{
3453 struct rb_node *n;
3454 struct ext4_group_info *grp;
3455 struct ext4_free_data *entry;
3456
3457 grp = ext4_get_group_info(sb, group);
3458 n = rb_first(&(grp->bb_free_root));
3459
3460 while (n) {
3461 entry = rb_entry(n, struct ext4_free_data, efd_node);
3462 ext4_set_bits(bitmap, entry->efd_start_cluster, entry->efd_count);
3463 n = rb_next(n);
3464 }
3465 return;
3466}
3467
3468/*
3469 * the function goes through all preallocation in this group and marks them
3470 * used in in-core bitmap. buddy must be generated from this bitmap
3471 * Need to be called with ext4 group lock held
3472 */
3473static noinline_for_stack
3474void ext4_mb_generate_from_pa(struct super_block *sb, void *bitmap,
3475 ext4_group_t group)
3476{
3477 struct ext4_group_info *grp = ext4_get_group_info(sb, group);
3478 struct ext4_prealloc_space *pa;
3479 struct list_head *cur;
3480 ext4_group_t groupnr;
3481 ext4_grpblk_t start;
3482 int preallocated = 0;
3483 int len;
3484
3485 /* all form of preallocation discards first load group,
3486 * so the only competing code is preallocation use.
3487 * we don't need any locking here
3488 * notice we do NOT ignore preallocations with pa_deleted
3489 * otherwise we could leave used blocks available for
3490 * allocation in buddy when concurrent ext4_mb_put_pa()
3491 * is dropping preallocation
3492 */
3493 list_for_each(cur, &grp->bb_prealloc_list) {
3494 pa = list_entry(cur, struct ext4_prealloc_space, pa_group_list);
3495 spin_lock(&pa->pa_lock);
3496 ext4_get_group_no_and_offset(sb, pa->pa_pstart,
3497 &groupnr, &start);
3498 len = pa->pa_len;
3499 spin_unlock(&pa->pa_lock);
3500 if (unlikely(len == 0))
3501 continue;
3502 BUG_ON(groupnr != group);
3503 ext4_set_bits(bitmap, start, len);
3504 preallocated += len;
3505 }
3506 mb_debug(1, "prellocated %u for group %u\n", preallocated, group);
3507}
3508
3509static void ext4_mb_pa_callback(struct rcu_head *head)
3510{
3511 struct ext4_prealloc_space *pa;
3512 pa = container_of(head, struct ext4_prealloc_space, u.pa_rcu);
3513
3514 BUG_ON(atomic_read(&pa->pa_count));
3515 BUG_ON(pa->pa_deleted == 0);
3516 kmem_cache_free(ext4_pspace_cachep, pa);
3517}
3518
3519/*
3520 * drops a reference to preallocated space descriptor
3521 * if this was the last reference and the space is consumed
3522 */
3523static void ext4_mb_put_pa(struct ext4_allocation_context *ac,
3524 struct super_block *sb, struct ext4_prealloc_space *pa)
3525{
3526 ext4_group_t grp;
3527 ext4_fsblk_t grp_blk;
3528
3529 /* in this short window concurrent discard can set pa_deleted */
3530 spin_lock(&pa->pa_lock);
3531 if (!atomic_dec_and_test(&pa->pa_count) || pa->pa_free != 0) {
3532 spin_unlock(&pa->pa_lock);
3533 return;
3534 }
3535
3536 if (pa->pa_deleted == 1) {
3537 spin_unlock(&pa->pa_lock);
3538 return;
3539 }
3540
3541 pa->pa_deleted = 1;
3542 spin_unlock(&pa->pa_lock);
3543
3544 grp_blk = pa->pa_pstart;
3545 /*
3546 * If doing group-based preallocation, pa_pstart may be in the
3547 * next group when pa is used up
3548 */
3549 if (pa->pa_type == MB_GROUP_PA)
3550 grp_blk--;
3551
3552 grp = ext4_get_group_number(sb, grp_blk);
3553
3554 /*
3555 * possible race:
3556 *
3557 * P1 (buddy init) P2 (regular allocation)
3558 * find block B in PA
3559 * copy on-disk bitmap to buddy
3560 * mark B in on-disk bitmap
3561 * drop PA from group
3562 * mark all PAs in buddy
3563 *
3564 * thus, P1 initializes buddy with B available. to prevent this
3565 * we make "copy" and "mark all PAs" atomic and serialize "drop PA"
3566 * against that pair
3567 */
3568 ext4_lock_group(sb, grp);
3569 list_del(&pa->pa_group_list);
3570 ext4_unlock_group(sb, grp);
3571
3572 spin_lock(pa->pa_obj_lock);
3573 list_del_rcu(&pa->pa_inode_list);
3574 spin_unlock(pa->pa_obj_lock);
3575
3576 call_rcu(&(pa)->u.pa_rcu, ext4_mb_pa_callback);
3577}
3578
3579/*
3580 * creates new preallocated space for given inode
3581 */
3582static noinline_for_stack int
3583ext4_mb_new_inode_pa(struct ext4_allocation_context *ac)
3584{
3585 struct super_block *sb = ac->ac_sb;
3586 struct ext4_sb_info *sbi = EXT4_SB(sb);
3587 struct ext4_prealloc_space *pa;
3588 struct ext4_group_info *grp;
3589 struct ext4_inode_info *ei;
3590
3591 /* preallocate only when found space is larger then requested */
3592 BUG_ON(ac->ac_o_ex.fe_len >= ac->ac_b_ex.fe_len);
3593 BUG_ON(ac->ac_status != AC_STATUS_FOUND);
3594 BUG_ON(!S_ISREG(ac->ac_inode->i_mode));
3595
3596 pa = kmem_cache_alloc(ext4_pspace_cachep, GFP_NOFS);
3597 if (pa == NULL)
3598 return -ENOMEM;
3599
3600 if (ac->ac_b_ex.fe_len < ac->ac_g_ex.fe_len) {
3601 int winl;
3602 int wins;
3603 int win;
3604 int offs;
3605
3606 /* we can't allocate as much as normalizer wants.
3607 * so, found space must get proper lstart
3608 * to cover original request */
3609 BUG_ON(ac->ac_g_ex.fe_logical > ac->ac_o_ex.fe_logical);
3610 BUG_ON(ac->ac_g_ex.fe_len < ac->ac_o_ex.fe_len);
3611
3612 /* we're limited by original request in that
3613 * logical block must be covered any way
3614 * winl is window we can move our chunk within */
3615 winl = ac->ac_o_ex.fe_logical - ac->ac_g_ex.fe_logical;
3616
3617 /* also, we should cover whole original request */
3618 wins = EXT4_C2B(sbi, ac->ac_b_ex.fe_len - ac->ac_o_ex.fe_len);
3619
3620 /* the smallest one defines real window */
3621 win = min(winl, wins);
3622
3623 offs = ac->ac_o_ex.fe_logical %
3624 EXT4_C2B(sbi, ac->ac_b_ex.fe_len);
3625 if (offs && offs < win)
3626 win = offs;
3627
3628 ac->ac_b_ex.fe_logical = ac->ac_o_ex.fe_logical -
3629 EXT4_NUM_B2C(sbi, win);
3630 BUG_ON(ac->ac_o_ex.fe_logical < ac->ac_b_ex.fe_logical);
3631 BUG_ON(ac->ac_o_ex.fe_len > ac->ac_b_ex.fe_len);
3632 }
3633
3634 /* preallocation can change ac_b_ex, thus we store actually
3635 * allocated blocks for history */
3636 ac->ac_f_ex = ac->ac_b_ex;
3637
3638 pa->pa_lstart = ac->ac_b_ex.fe_logical;
3639 pa->pa_pstart = ext4_grp_offs_to_block(sb, &ac->ac_b_ex);
3640 pa->pa_len = ac->ac_b_ex.fe_len;
3641 pa->pa_free = pa->pa_len;
3642 atomic_set(&pa->pa_count, 1);
3643 spin_lock_init(&pa->pa_lock);
3644 INIT_LIST_HEAD(&pa->pa_inode_list);
3645 INIT_LIST_HEAD(&pa->pa_group_list);
3646 pa->pa_deleted = 0;
3647 pa->pa_type = MB_INODE_PA;
3648
3649 mb_debug(1, "new inode pa %p: %llu/%u for %u\n", pa,
3650 pa->pa_pstart, pa->pa_len, pa->pa_lstart);
3651 trace_ext4_mb_new_inode_pa(ac, pa);
3652
3653 ext4_mb_use_inode_pa(ac, pa);
3654 atomic_add(pa->pa_free, &sbi->s_mb_preallocated);
3655
3656 ei = EXT4_I(ac->ac_inode);
3657 grp = ext4_get_group_info(sb, ac->ac_b_ex.fe_group);
3658
3659 pa->pa_obj_lock = &ei->i_prealloc_lock;
3660 pa->pa_inode = ac->ac_inode;
3661
3662 ext4_lock_group(sb, ac->ac_b_ex.fe_group);
3663 list_add(&pa->pa_group_list, &grp->bb_prealloc_list);
3664 ext4_unlock_group(sb, ac->ac_b_ex.fe_group);
3665
3666 spin_lock(pa->pa_obj_lock);
3667 list_add_rcu(&pa->pa_inode_list, &ei->i_prealloc_list);
3668 spin_unlock(pa->pa_obj_lock);
3669
3670 return 0;
3671}
3672
3673/*
3674 * creates new preallocated space for locality group inodes belongs to
3675 */
3676static noinline_for_stack int
3677ext4_mb_new_group_pa(struct ext4_allocation_context *ac)
3678{
3679 struct super_block *sb = ac->ac_sb;
3680 struct ext4_locality_group *lg;
3681 struct ext4_prealloc_space *pa;
3682 struct ext4_group_info *grp;
3683
3684 /* preallocate only when found space is larger then requested */
3685 BUG_ON(ac->ac_o_ex.fe_len >= ac->ac_b_ex.fe_len);
3686 BUG_ON(ac->ac_status != AC_STATUS_FOUND);
3687 BUG_ON(!S_ISREG(ac->ac_inode->i_mode));
3688
3689 BUG_ON(ext4_pspace_cachep == NULL);
3690 pa = kmem_cache_alloc(ext4_pspace_cachep, GFP_NOFS);
3691 if (pa == NULL)
3692 return -ENOMEM;
3693
3694 /* preallocation can change ac_b_ex, thus we store actually
3695 * allocated blocks for history */
3696 ac->ac_f_ex = ac->ac_b_ex;
3697
3698 pa->pa_pstart = ext4_grp_offs_to_block(sb, &ac->ac_b_ex);
3699 pa->pa_lstart = pa->pa_pstart;
3700 pa->pa_len = ac->ac_b_ex.fe_len;
3701 pa->pa_free = pa->pa_len;
3702 atomic_set(&pa->pa_count, 1);
3703 spin_lock_init(&pa->pa_lock);
3704 INIT_LIST_HEAD(&pa->pa_inode_list);
3705 INIT_LIST_HEAD(&pa->pa_group_list);
3706 pa->pa_deleted = 0;
3707 pa->pa_type = MB_GROUP_PA;
3708
3709 mb_debug(1, "new group pa %p: %llu/%u for %u\n", pa,
3710 pa->pa_pstart, pa->pa_len, pa->pa_lstart);
3711 trace_ext4_mb_new_group_pa(ac, pa);
3712
3713 ext4_mb_use_group_pa(ac, pa);
3714 atomic_add(pa->pa_free, &EXT4_SB(sb)->s_mb_preallocated);
3715
3716 grp = ext4_get_group_info(sb, ac->ac_b_ex.fe_group);
3717 lg = ac->ac_lg;
3718 BUG_ON(lg == NULL);
3719
3720 pa->pa_obj_lock = &lg->lg_prealloc_lock;
3721 pa->pa_inode = NULL;
3722
3723 ext4_lock_group(sb, ac->ac_b_ex.fe_group);
3724 list_add(&pa->pa_group_list, &grp->bb_prealloc_list);
3725 ext4_unlock_group(sb, ac->ac_b_ex.fe_group);
3726
3727 /*
3728 * We will later add the new pa to the right bucket
3729 * after updating the pa_free in ext4_mb_release_context
3730 */
3731 return 0;
3732}
3733
3734static int ext4_mb_new_preallocation(struct ext4_allocation_context *ac)
3735{
3736 int err;
3737
3738 if (ac->ac_flags & EXT4_MB_HINT_GROUP_ALLOC)
3739 err = ext4_mb_new_group_pa(ac);
3740 else
3741 err = ext4_mb_new_inode_pa(ac);
3742 return err;
3743}
3744
3745/*
3746 * finds all unused blocks in on-disk bitmap, frees them in
3747 * in-core bitmap and buddy.
3748 * @pa must be unlinked from inode and group lists, so that
3749 * nobody else can find/use it.
3750 * the caller MUST hold group/inode locks.
3751 * TODO: optimize the case when there are no in-core structures yet
3752 */
3753static noinline_for_stack int
3754ext4_mb_release_inode_pa(struct ext4_buddy *e4b, struct buffer_head *bitmap_bh,
3755 struct ext4_prealloc_space *pa)
3756{
3757 struct super_block *sb = e4b->bd_sb;
3758 struct ext4_sb_info *sbi = EXT4_SB(sb);
3759 unsigned int end;
3760 unsigned int next;
3761 ext4_group_t group;
3762 ext4_grpblk_t bit;
3763 unsigned long long grp_blk_start;
3764 int err = 0;
3765 int free = 0;
3766
3767 BUG_ON(pa->pa_deleted == 0);
3768 ext4_get_group_no_and_offset(sb, pa->pa_pstart, &group, &bit);
3769 grp_blk_start = pa->pa_pstart - EXT4_C2B(sbi, bit);
3770 BUG_ON(group != e4b->bd_group && pa->pa_len != 0);
3771 end = bit + pa->pa_len;
3772
3773 while (bit < end) {
3774 bit = mb_find_next_zero_bit(bitmap_bh->b_data, end, bit);
3775 if (bit >= end)
3776 break;
3777 next = mb_find_next_bit(bitmap_bh->b_data, end, bit);
3778 mb_debug(1, " free preallocated %u/%u in group %u\n",
3779 (unsigned) ext4_group_first_block_no(sb, group) + bit,
3780 (unsigned) next - bit, (unsigned) group);
3781 free += next - bit;
3782
3783 trace_ext4_mballoc_discard(sb, NULL, group, bit, next - bit);
3784 trace_ext4_mb_release_inode_pa(pa, (grp_blk_start +
3785 EXT4_C2B(sbi, bit)),
3786 next - bit);
3787 mb_free_blocks(pa->pa_inode, e4b, bit, next - bit);
3788 bit = next + 1;
3789 }
3790 if (free != pa->pa_free) {
3791 ext4_msg(e4b->bd_sb, KERN_CRIT,
3792 "pa %p: logic %lu, phys. %lu, len %lu",
3793 pa, (unsigned long) pa->pa_lstart,
3794 (unsigned long) pa->pa_pstart,
3795 (unsigned long) pa->pa_len);
3796 ext4_grp_locked_error(sb, group, 0, 0, "free %u, pa_free %u",
3797 free, pa->pa_free);
3798 /*
3799 * pa is already deleted so we use the value obtained
3800 * from the bitmap and continue.
3801 */
3802 }
3803 atomic_add(free, &sbi->s_mb_discarded);
3804
3805 return err;
3806}
3807
3808static noinline_for_stack int
3809ext4_mb_release_group_pa(struct ext4_buddy *e4b,
3810 struct ext4_prealloc_space *pa)
3811{
3812 struct super_block *sb = e4b->bd_sb;
3813 ext4_group_t group;
3814 ext4_grpblk_t bit;
3815
3816 trace_ext4_mb_release_group_pa(sb, pa);
3817 BUG_ON(pa->pa_deleted == 0);
3818 ext4_get_group_no_and_offset(sb, pa->pa_pstart, &group, &bit);
3819 BUG_ON(group != e4b->bd_group && pa->pa_len != 0);
3820 mb_free_blocks(pa->pa_inode, e4b, bit, pa->pa_len);
3821 atomic_add(pa->pa_len, &EXT4_SB(sb)->s_mb_discarded);
3822 trace_ext4_mballoc_discard(sb, NULL, group, bit, pa->pa_len);
3823
3824 return 0;
3825}
3826
3827/*
3828 * releases all preallocations in given group
3829 *
3830 * first, we need to decide discard policy:
3831 * - when do we discard
3832 * 1) ENOSPC
3833 * - how many do we discard
3834 * 1) how many requested
3835 */
3836static noinline_for_stack int
3837ext4_mb_discard_group_preallocations(struct super_block *sb,
3838 ext4_group_t group, int needed)
3839{
3840 struct ext4_group_info *grp = ext4_get_group_info(sb, group);
3841 struct buffer_head *bitmap_bh = NULL;
3842 struct ext4_prealloc_space *pa, *tmp;
3843 struct list_head list;
3844 struct ext4_buddy e4b;
3845 int err;
3846 int busy = 0;
3847 int free = 0;
3848
3849 mb_debug(1, "discard preallocation for group %u\n", group);
3850
3851 if (list_empty(&grp->bb_prealloc_list))
3852 return 0;
3853
3854 bitmap_bh = ext4_read_block_bitmap(sb, group);
3855 if (IS_ERR(bitmap_bh)) {
3856 err = PTR_ERR(bitmap_bh);
3857 ext4_error(sb, "Error %d reading block bitmap for %u",
3858 err, group);
3859 return 0;
3860 }
3861
3862 err = ext4_mb_load_buddy(sb, group, &e4b);
3863 if (err) {
3864 ext4_error(sb, "Error loading buddy information for %u", group);
3865 put_bh(bitmap_bh);
3866 return 0;
3867 }
3868
3869 if (needed == 0)
3870 needed = EXT4_CLUSTERS_PER_GROUP(sb) + 1;
3871
3872 INIT_LIST_HEAD(&list);
3873repeat:
3874 ext4_lock_group(sb, group);
3875 list_for_each_entry_safe(pa, tmp,
3876 &grp->bb_prealloc_list, pa_group_list) {
3877 spin_lock(&pa->pa_lock);
3878 if (atomic_read(&pa->pa_count)) {
3879 spin_unlock(&pa->pa_lock);
3880 busy = 1;
3881 continue;
3882 }
3883 if (pa->pa_deleted) {
3884 spin_unlock(&pa->pa_lock);
3885 continue;
3886 }
3887
3888 /* seems this one can be freed ... */
3889 pa->pa_deleted = 1;
3890
3891 /* we can trust pa_free ... */
3892 free += pa->pa_free;
3893
3894 spin_unlock(&pa->pa_lock);
3895
3896 list_del(&pa->pa_group_list);
3897 list_add(&pa->u.pa_tmp_list, &list);
3898 }
3899
3900 /* if we still need more blocks and some PAs were used, try again */
3901 if (free < needed && busy) {
3902 busy = 0;
3903 ext4_unlock_group(sb, group);
3904 cond_resched();
3905 goto repeat;
3906 }
3907
3908 /* found anything to free? */
3909 if (list_empty(&list)) {
3910 BUG_ON(free != 0);
3911 goto out;
3912 }
3913
3914 /* now free all selected PAs */
3915 list_for_each_entry_safe(pa, tmp, &list, u.pa_tmp_list) {
3916
3917 /* remove from object (inode or locality group) */
3918 spin_lock(pa->pa_obj_lock);
3919 list_del_rcu(&pa->pa_inode_list);
3920 spin_unlock(pa->pa_obj_lock);
3921
3922 if (pa->pa_type == MB_GROUP_PA)
3923 ext4_mb_release_group_pa(&e4b, pa);
3924 else
3925 ext4_mb_release_inode_pa(&e4b, bitmap_bh, pa);
3926
3927 list_del(&pa->u.pa_tmp_list);
3928 call_rcu(&(pa)->u.pa_rcu, ext4_mb_pa_callback);
3929 }
3930
3931out:
3932 ext4_unlock_group(sb, group);
3933 ext4_mb_unload_buddy(&e4b);
3934 put_bh(bitmap_bh);
3935 return free;
3936}
3937
3938/*
3939 * releases all non-used preallocated blocks for given inode
3940 *
3941 * It's important to discard preallocations under i_data_sem
3942 * We don't want another block to be served from the prealloc
3943 * space when we are discarding the inode prealloc space.
3944 *
3945 * FIXME!! Make sure it is valid at all the call sites
3946 */
3947void ext4_discard_preallocations(struct inode *inode)
3948{
3949 struct ext4_inode_info *ei = EXT4_I(inode);
3950 struct super_block *sb = inode->i_sb;
3951 struct buffer_head *bitmap_bh = NULL;
3952 struct ext4_prealloc_space *pa, *tmp;
3953 ext4_group_t group = 0;
3954 struct list_head list;
3955 struct ext4_buddy e4b;
3956 int err;
3957
3958 if (!S_ISREG(inode->i_mode)) {
3959 /*BUG_ON(!list_empty(&ei->i_prealloc_list));*/
3960 return;
3961 }
3962
3963 mb_debug(1, "discard preallocation for inode %lu\n", inode->i_ino);
3964 trace_ext4_discard_preallocations(inode);
3965
3966 INIT_LIST_HEAD(&list);
3967
3968repeat:
3969 /* first, collect all pa's in the inode */
3970 spin_lock(&ei->i_prealloc_lock);
3971 while (!list_empty(&ei->i_prealloc_list)) {
3972 pa = list_entry(ei->i_prealloc_list.next,
3973 struct ext4_prealloc_space, pa_inode_list);
3974 BUG_ON(pa->pa_obj_lock != &ei->i_prealloc_lock);
3975 spin_lock(&pa->pa_lock);
3976 if (atomic_read(&pa->pa_count)) {
3977 /* this shouldn't happen often - nobody should
3978 * use preallocation while we're discarding it */
3979 spin_unlock(&pa->pa_lock);
3980 spin_unlock(&ei->i_prealloc_lock);
3981 ext4_msg(sb, KERN_ERR,
3982 "uh-oh! used pa while discarding");
3983 WARN_ON(1);
3984 schedule_timeout_uninterruptible(HZ);
3985 goto repeat;
3986
3987 }
3988 if (pa->pa_deleted == 0) {
3989 pa->pa_deleted = 1;
3990 spin_unlock(&pa->pa_lock);
3991 list_del_rcu(&pa->pa_inode_list);
3992 list_add(&pa->u.pa_tmp_list, &list);
3993 continue;
3994 }
3995
3996 /* someone is deleting pa right now */
3997 spin_unlock(&pa->pa_lock);
3998 spin_unlock(&ei->i_prealloc_lock);
3999
4000 /* we have to wait here because pa_deleted
4001 * doesn't mean pa is already unlinked from
4002 * the list. as we might be called from
4003 * ->clear_inode() the inode will get freed
4004 * and concurrent thread which is unlinking
4005 * pa from inode's list may access already
4006 * freed memory, bad-bad-bad */
4007
4008 /* XXX: if this happens too often, we can
4009 * add a flag to force wait only in case
4010 * of ->clear_inode(), but not in case of
4011 * regular truncate */
4012 schedule_timeout_uninterruptible(HZ);
4013 goto repeat;
4014 }
4015 spin_unlock(&ei->i_prealloc_lock);
4016
4017 list_for_each_entry_safe(pa, tmp, &list, u.pa_tmp_list) {
4018 BUG_ON(pa->pa_type != MB_INODE_PA);
4019 group = ext4_get_group_number(sb, pa->pa_pstart);
4020
4021 err = ext4_mb_load_buddy(sb, group, &e4b);
4022 if (err) {
4023 ext4_error(sb, "Error loading buddy information for %u",
4024 group);
4025 continue;
4026 }
4027
4028 bitmap_bh = ext4_read_block_bitmap(sb, group);
4029 if (IS_ERR(bitmap_bh)) {
4030 err = PTR_ERR(bitmap_bh);
4031 ext4_error(sb, "Error %d reading block bitmap for %u",
4032 err, group);
4033 ext4_mb_unload_buddy(&e4b);
4034 continue;
4035 }
4036
4037 ext4_lock_group(sb, group);
4038 list_del(&pa->pa_group_list);
4039 ext4_mb_release_inode_pa(&e4b, bitmap_bh, pa);
4040 ext4_unlock_group(sb, group);
4041
4042 ext4_mb_unload_buddy(&e4b);
4043 put_bh(bitmap_bh);
4044
4045 list_del(&pa->u.pa_tmp_list);
4046 call_rcu(&(pa)->u.pa_rcu, ext4_mb_pa_callback);
4047 }
4048}
4049
4050#ifdef CONFIG_EXT4_DEBUG
4051static void ext4_mb_show_ac(struct ext4_allocation_context *ac)
4052{
4053 struct super_block *sb = ac->ac_sb;
4054 ext4_group_t ngroups, i;
4055
4056 if (!ext4_mballoc_debug ||
4057 (EXT4_SB(sb)->s_mount_flags & EXT4_MF_FS_ABORTED))
4058 return;
4059
4060 ext4_msg(ac->ac_sb, KERN_ERR, "Can't allocate:"
4061 " Allocation context details:");
4062 ext4_msg(ac->ac_sb, KERN_ERR, "status %d flags %d",
4063 ac->ac_status, ac->ac_flags);
4064 ext4_msg(ac->ac_sb, KERN_ERR, "orig %lu/%lu/%lu@%lu, "
4065 "goal %lu/%lu/%lu@%lu, "
4066 "best %lu/%lu/%lu@%lu cr %d",
4067 (unsigned long)ac->ac_o_ex.fe_group,
4068 (unsigned long)ac->ac_o_ex.fe_start,
4069 (unsigned long)ac->ac_o_ex.fe_len,
4070 (unsigned long)ac->ac_o_ex.fe_logical,
4071 (unsigned long)ac->ac_g_ex.fe_group,
4072 (unsigned long)ac->ac_g_ex.fe_start,
4073 (unsigned long)ac->ac_g_ex.fe_len,
4074 (unsigned long)ac->ac_g_ex.fe_logical,
4075 (unsigned long)ac->ac_b_ex.fe_group,
4076 (unsigned long)ac->ac_b_ex.fe_start,
4077 (unsigned long)ac->ac_b_ex.fe_len,
4078 (unsigned long)ac->ac_b_ex.fe_logical,
4079 (int)ac->ac_criteria);
4080 ext4_msg(ac->ac_sb, KERN_ERR, "%d found", ac->ac_found);
4081 ext4_msg(ac->ac_sb, KERN_ERR, "groups: ");
4082 ngroups = ext4_get_groups_count(sb);
4083 for (i = 0; i < ngroups; i++) {
4084 struct ext4_group_info *grp = ext4_get_group_info(sb, i);
4085 struct ext4_prealloc_space *pa;
4086 ext4_grpblk_t start;
4087 struct list_head *cur;
4088 ext4_lock_group(sb, i);
4089 list_for_each(cur, &grp->bb_prealloc_list) {
4090 pa = list_entry(cur, struct ext4_prealloc_space,
4091 pa_group_list);
4092 spin_lock(&pa->pa_lock);
4093 ext4_get_group_no_and_offset(sb, pa->pa_pstart,
4094 NULL, &start);
4095 spin_unlock(&pa->pa_lock);
4096 printk(KERN_ERR "PA:%u:%d:%u \n", i,
4097 start, pa->pa_len);
4098 }
4099 ext4_unlock_group(sb, i);
4100
4101 if (grp->bb_free == 0)
4102 continue;
4103 printk(KERN_ERR "%u: %d/%d \n",
4104 i, grp->bb_free, grp->bb_fragments);
4105 }
4106 printk(KERN_ERR "\n");
4107}
4108#else
4109static inline void ext4_mb_show_ac(struct ext4_allocation_context *ac)
4110{
4111 return;
4112}
4113#endif
4114
4115/*
4116 * We use locality group preallocation for small size file. The size of the
4117 * file is determined by the current size or the resulting size after
4118 * allocation which ever is larger
4119 *
4120 * One can tune this size via /sys/fs/ext4/<partition>/mb_stream_req
4121 */
4122static void ext4_mb_group_or_file(struct ext4_allocation_context *ac)
4123{
4124 struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
4125 int bsbits = ac->ac_sb->s_blocksize_bits;
4126 loff_t size, isize;
4127
4128 if (!(ac->ac_flags & EXT4_MB_HINT_DATA))
4129 return;
4130
4131 if (unlikely(ac->ac_flags & EXT4_MB_HINT_GOAL_ONLY))
4132 return;
4133
4134 size = ac->ac_o_ex.fe_logical + EXT4_C2B(sbi, ac->ac_o_ex.fe_len);
4135 isize = (i_size_read(ac->ac_inode) + ac->ac_sb->s_blocksize - 1)
4136 >> bsbits;
4137
4138 if ((size == isize) &&
4139 !ext4_fs_is_busy(sbi) &&
4140 (atomic_read(&ac->ac_inode->i_writecount) == 0)) {
4141 ac->ac_flags |= EXT4_MB_HINT_NOPREALLOC;
4142 return;
4143 }
4144
4145 if (sbi->s_mb_group_prealloc <= 0) {
4146 ac->ac_flags |= EXT4_MB_STREAM_ALLOC;
4147 return;
4148 }
4149
4150 /* don't use group allocation for large files */
4151 size = max(size, isize);
4152 if (size > sbi->s_mb_stream_request) {
4153 ac->ac_flags |= EXT4_MB_STREAM_ALLOC;
4154 return;
4155 }
4156
4157 BUG_ON(ac->ac_lg != NULL);
4158 /*
4159 * locality group prealloc space are per cpu. The reason for having
4160 * per cpu locality group is to reduce the contention between block
4161 * request from multiple CPUs.
4162 */
4163 ac->ac_lg = raw_cpu_ptr(sbi->s_locality_groups);
4164
4165 /* we're going to use group allocation */
4166 ac->ac_flags |= EXT4_MB_HINT_GROUP_ALLOC;
4167
4168 /* serialize all allocations in the group */
4169 mutex_lock(&ac->ac_lg->lg_mutex);
4170}
4171
4172static noinline_for_stack int
4173ext4_mb_initialize_context(struct ext4_allocation_context *ac,
4174 struct ext4_allocation_request *ar)
4175{
4176 struct super_block *sb = ar->inode->i_sb;
4177 struct ext4_sb_info *sbi = EXT4_SB(sb);
4178 struct ext4_super_block *es = sbi->s_es;
4179 ext4_group_t group;
4180 unsigned int len;
4181 ext4_fsblk_t goal;
4182 ext4_grpblk_t block;
4183
4184 /* we can't allocate > group size */
4185 len = ar->len;
4186
4187 /* just a dirty hack to filter too big requests */
4188 if (len >= EXT4_CLUSTERS_PER_GROUP(sb))
4189 len = EXT4_CLUSTERS_PER_GROUP(sb);
4190
4191 /* start searching from the goal */
4192 goal = ar->goal;
4193 if (goal < le32_to_cpu(es->s_first_data_block) ||
4194 goal >= ext4_blocks_count(es))
4195 goal = le32_to_cpu(es->s_first_data_block);
4196 ext4_get_group_no_and_offset(sb, goal, &group, &block);
4197
4198 /* set up allocation goals */
4199 ac->ac_b_ex.fe_logical = EXT4_LBLK_CMASK(sbi, ar->logical);
4200 ac->ac_status = AC_STATUS_CONTINUE;
4201 ac->ac_sb = sb;
4202 ac->ac_inode = ar->inode;
4203 ac->ac_o_ex.fe_logical = ac->ac_b_ex.fe_logical;
4204 ac->ac_o_ex.fe_group = group;
4205 ac->ac_o_ex.fe_start = block;
4206 ac->ac_o_ex.fe_len = len;
4207 ac->ac_g_ex = ac->ac_o_ex;
4208 ac->ac_flags = ar->flags;
4209
4210 /* we have to define context: we'll we work with a file or
4211 * locality group. this is a policy, actually */
4212 ext4_mb_group_or_file(ac);
4213
4214 mb_debug(1, "init ac: %u blocks @ %u, goal %u, flags %x, 2^%d, "
4215 "left: %u/%u, right %u/%u to %swritable\n",
4216 (unsigned) ar->len, (unsigned) ar->logical,
4217 (unsigned) ar->goal, ac->ac_flags, ac->ac_2order,
4218 (unsigned) ar->lleft, (unsigned) ar->pleft,
4219 (unsigned) ar->lright, (unsigned) ar->pright,
4220 atomic_read(&ar->inode->i_writecount) ? "" : "non-");
4221 return 0;
4222
4223}
4224
4225static noinline_for_stack void
4226ext4_mb_discard_lg_preallocations(struct super_block *sb,
4227 struct ext4_locality_group *lg,
4228 int order, int total_entries)
4229{
4230 ext4_group_t group = 0;
4231 struct ext4_buddy e4b;
4232 struct list_head discard_list;
4233 struct ext4_prealloc_space *pa, *tmp;
4234
4235 mb_debug(1, "discard locality group preallocation\n");
4236
4237 INIT_LIST_HEAD(&discard_list);
4238
4239 spin_lock(&lg->lg_prealloc_lock);
4240 list_for_each_entry_rcu(pa, &lg->lg_prealloc_list[order],
4241 pa_inode_list) {
4242 spin_lock(&pa->pa_lock);
4243 if (atomic_read(&pa->pa_count)) {
4244 /*
4245 * This is the pa that we just used
4246 * for block allocation. So don't
4247 * free that
4248 */
4249 spin_unlock(&pa->pa_lock);
4250 continue;
4251 }
4252 if (pa->pa_deleted) {
4253 spin_unlock(&pa->pa_lock);
4254 continue;
4255 }
4256 /* only lg prealloc space */
4257 BUG_ON(pa->pa_type != MB_GROUP_PA);
4258
4259 /* seems this one can be freed ... */
4260 pa->pa_deleted = 1;
4261 spin_unlock(&pa->pa_lock);
4262
4263 list_del_rcu(&pa->pa_inode_list);
4264 list_add(&pa->u.pa_tmp_list, &discard_list);
4265
4266 total_entries--;
4267 if (total_entries <= 5) {
4268 /*
4269 * we want to keep only 5 entries
4270 * allowing it to grow to 8. This
4271 * mak sure we don't call discard
4272 * soon for this list.
4273 */
4274 break;
4275 }
4276 }
4277 spin_unlock(&lg->lg_prealloc_lock);
4278
4279 list_for_each_entry_safe(pa, tmp, &discard_list, u.pa_tmp_list) {
4280
4281 group = ext4_get_group_number(sb, pa->pa_pstart);
4282 if (ext4_mb_load_buddy(sb, group, &e4b)) {
4283 ext4_error(sb, "Error loading buddy information for %u",
4284 group);
4285 continue;
4286 }
4287 ext4_lock_group(sb, group);
4288 list_del(&pa->pa_group_list);
4289 ext4_mb_release_group_pa(&e4b, pa);
4290 ext4_unlock_group(sb, group);
4291
4292 ext4_mb_unload_buddy(&e4b);
4293 list_del(&pa->u.pa_tmp_list);
4294 call_rcu(&(pa)->u.pa_rcu, ext4_mb_pa_callback);
4295 }
4296}
4297
4298/*
4299 * We have incremented pa_count. So it cannot be freed at this
4300 * point. Also we hold lg_mutex. So no parallel allocation is
4301 * possible from this lg. That means pa_free cannot be updated.
4302 *
4303 * A parallel ext4_mb_discard_group_preallocations is possible.
4304 * which can cause the lg_prealloc_list to be updated.
4305 */
4306
4307static void ext4_mb_add_n_trim(struct ext4_allocation_context *ac)
4308{
4309 int order, added = 0, lg_prealloc_count = 1;
4310 struct super_block *sb = ac->ac_sb;
4311 struct ext4_locality_group *lg = ac->ac_lg;
4312 struct ext4_prealloc_space *tmp_pa, *pa = ac->ac_pa;
4313
4314 order = fls(pa->pa_free) - 1;
4315 if (order > PREALLOC_TB_SIZE - 1)
4316 /* The max size of hash table is PREALLOC_TB_SIZE */
4317 order = PREALLOC_TB_SIZE - 1;
4318 /* Add the prealloc space to lg */
4319 spin_lock(&lg->lg_prealloc_lock);
4320 list_for_each_entry_rcu(tmp_pa, &lg->lg_prealloc_list[order],
4321 pa_inode_list) {
4322 spin_lock(&tmp_pa->pa_lock);
4323 if (tmp_pa->pa_deleted) {
4324 spin_unlock(&tmp_pa->pa_lock);
4325 continue;
4326 }
4327 if (!added && pa->pa_free < tmp_pa->pa_free) {
4328 /* Add to the tail of the previous entry */
4329 list_add_tail_rcu(&pa->pa_inode_list,
4330 &tmp_pa->pa_inode_list);
4331 added = 1;
4332 /*
4333 * we want to count the total
4334 * number of entries in the list
4335 */
4336 }
4337 spin_unlock(&tmp_pa->pa_lock);
4338 lg_prealloc_count++;
4339 }
4340 if (!added)
4341 list_add_tail_rcu(&pa->pa_inode_list,
4342 &lg->lg_prealloc_list[order]);
4343 spin_unlock(&lg->lg_prealloc_lock);
4344
4345 /* Now trim the list to be not more than 8 elements */
4346 if (lg_prealloc_count > 8) {
4347 ext4_mb_discard_lg_preallocations(sb, lg,
4348 order, lg_prealloc_count);
4349 return;
4350 }
4351 return ;
4352}
4353
4354/*
4355 * release all resource we used in allocation
4356 */
4357static int ext4_mb_release_context(struct ext4_allocation_context *ac)
4358{
4359 struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
4360 struct ext4_prealloc_space *pa = ac->ac_pa;
4361 if (pa) {
4362 if (pa->pa_type == MB_GROUP_PA) {
4363 /* see comment in ext4_mb_use_group_pa() */
4364 spin_lock(&pa->pa_lock);
4365 pa->pa_pstart += EXT4_C2B(sbi, ac->ac_b_ex.fe_len);
4366 pa->pa_lstart += EXT4_C2B(sbi, ac->ac_b_ex.fe_len);
4367 pa->pa_free -= ac->ac_b_ex.fe_len;
4368 pa->pa_len -= ac->ac_b_ex.fe_len;
4369 spin_unlock(&pa->pa_lock);
4370 }
4371 }
4372 if (pa) {
4373 /*
4374 * We want to add the pa to the right bucket.
4375 * Remove it from the list and while adding
4376 * make sure the list to which we are adding
4377 * doesn't grow big.
4378 */
4379 if ((pa->pa_type == MB_GROUP_PA) && likely(pa->pa_free)) {
4380 spin_lock(pa->pa_obj_lock);
4381 list_del_rcu(&pa->pa_inode_list);
4382 spin_unlock(pa->pa_obj_lock);
4383 ext4_mb_add_n_trim(ac);
4384 }
4385 ext4_mb_put_pa(ac, ac->ac_sb, pa);
4386 }
4387 if (ac->ac_bitmap_page)
4388 put_page(ac->ac_bitmap_page);
4389 if (ac->ac_buddy_page)
4390 put_page(ac->ac_buddy_page);
4391 if (ac->ac_flags & EXT4_MB_HINT_GROUP_ALLOC)
4392 mutex_unlock(&ac->ac_lg->lg_mutex);
4393 ext4_mb_collect_stats(ac);
4394 return 0;
4395}
4396
4397static int ext4_mb_discard_preallocations(struct super_block *sb, int needed)
4398{
4399 ext4_group_t i, ngroups = ext4_get_groups_count(sb);
4400 int ret;
4401 int freed = 0;
4402
4403 trace_ext4_mb_discard_preallocations(sb, needed);
4404 for (i = 0; i < ngroups && needed > 0; i++) {
4405 ret = ext4_mb_discard_group_preallocations(sb, i, needed);
4406 freed += ret;
4407 needed -= ret;
4408 }
4409
4410 return freed;
4411}
4412
4413/*
4414 * Main entry point into mballoc to allocate blocks
4415 * it tries to use preallocation first, then falls back
4416 * to usual allocation
4417 */
4418ext4_fsblk_t ext4_mb_new_blocks(handle_t *handle,
4419 struct ext4_allocation_request *ar, int *errp)
4420{
4421 int freed;
4422 struct ext4_allocation_context *ac = NULL;
4423 struct ext4_sb_info *sbi;
4424 struct super_block *sb;
4425 ext4_fsblk_t block = 0;
4426 unsigned int inquota = 0;
4427 unsigned int reserv_clstrs = 0;
4428
4429 might_sleep();
4430 sb = ar->inode->i_sb;
4431 sbi = EXT4_SB(sb);
4432
4433 trace_ext4_request_blocks(ar);
4434
4435 /* Allow to use superuser reservation for quota file */
4436 if (IS_NOQUOTA(ar->inode))
4437 ar->flags |= EXT4_MB_USE_ROOT_BLOCKS;
4438
4439 if ((ar->flags & EXT4_MB_DELALLOC_RESERVED) == 0) {
4440 /* Without delayed allocation we need to verify
4441 * there is enough free blocks to do block allocation
4442 * and verify allocation doesn't exceed the quota limits.
4443 */
4444 while (ar->len &&
4445 ext4_claim_free_clusters(sbi, ar->len, ar->flags)) {
4446
4447 /* let others to free the space */
4448 cond_resched();
4449 ar->len = ar->len >> 1;
4450 }
4451 if (!ar->len) {
4452 *errp = -ENOSPC;
4453 return 0;
4454 }
4455 reserv_clstrs = ar->len;
4456 if (ar->flags & EXT4_MB_USE_ROOT_BLOCKS) {
4457 dquot_alloc_block_nofail(ar->inode,
4458 EXT4_C2B(sbi, ar->len));
4459 } else {
4460 while (ar->len &&
4461 dquot_alloc_block(ar->inode,
4462 EXT4_C2B(sbi, ar->len))) {
4463
4464 ar->flags |= EXT4_MB_HINT_NOPREALLOC;
4465 ar->len--;
4466 }
4467 }
4468 inquota = ar->len;
4469 if (ar->len == 0) {
4470 *errp = -EDQUOT;
4471 goto out;
4472 }
4473 }
4474
4475 ac = kmem_cache_zalloc(ext4_ac_cachep, GFP_NOFS);
4476 if (!ac) {
4477 ar->len = 0;
4478 *errp = -ENOMEM;
4479 goto out;
4480 }
4481
4482 *errp = ext4_mb_initialize_context(ac, ar);
4483 if (*errp) {
4484 ar->len = 0;
4485 goto out;
4486 }
4487
4488 ac->ac_op = EXT4_MB_HISTORY_PREALLOC;
4489 if (!ext4_mb_use_preallocated(ac)) {
4490 ac->ac_op = EXT4_MB_HISTORY_ALLOC;
4491 ext4_mb_normalize_request(ac, ar);
4492repeat:
4493 /* allocate space in core */
4494 *errp = ext4_mb_regular_allocator(ac);
4495 if (*errp)
4496 goto discard_and_exit;
4497
4498 /* as we've just preallocated more space than
4499 * user requested originally, we store allocated
4500 * space in a special descriptor */
4501 if (ac->ac_status == AC_STATUS_FOUND &&
4502 ac->ac_o_ex.fe_len < ac->ac_b_ex.fe_len)
4503 *errp = ext4_mb_new_preallocation(ac);
4504 if (*errp) {
4505 discard_and_exit:
4506 ext4_discard_allocated_blocks(ac);
4507 goto errout;
4508 }
4509 }
4510 if (likely(ac->ac_status == AC_STATUS_FOUND)) {
4511 *errp = ext4_mb_mark_diskspace_used(ac, handle, reserv_clstrs);
4512 if (*errp == -EAGAIN) {
4513 /*
4514 * drop the reference that we took
4515 * in ext4_mb_use_best_found
4516 */
4517 ext4_mb_release_context(ac);
4518 ac->ac_b_ex.fe_group = 0;
4519 ac->ac_b_ex.fe_start = 0;
4520 ac->ac_b_ex.fe_len = 0;
4521 ac->ac_status = AC_STATUS_CONTINUE;
4522 goto repeat;
4523 } else if (*errp) {
4524 ext4_discard_allocated_blocks(ac);
4525 goto errout;
4526 } else {
4527 block = ext4_grp_offs_to_block(sb, &ac->ac_b_ex);
4528 ar->len = ac->ac_b_ex.fe_len;
4529 }
4530 } else {
4531 freed = ext4_mb_discard_preallocations(sb, ac->ac_o_ex.fe_len);
4532 if (freed)
4533 goto repeat;
4534 *errp = -ENOSPC;
4535 }
4536
4537errout:
4538 if (*errp) {
4539 ac->ac_b_ex.fe_len = 0;
4540 ar->len = 0;
4541 ext4_mb_show_ac(ac);
4542 }
4543 ext4_mb_release_context(ac);
4544out:
4545 if (ac)
4546 kmem_cache_free(ext4_ac_cachep, ac);
4547 if (inquota && ar->len < inquota)
4548 dquot_free_block(ar->inode, EXT4_C2B(sbi, inquota - ar->len));
4549 if (!ar->len) {
4550 if ((ar->flags & EXT4_MB_DELALLOC_RESERVED) == 0)
4551 /* release all the reserved blocks if non delalloc */
4552 percpu_counter_sub(&sbi->s_dirtyclusters_counter,
4553 reserv_clstrs);
4554 }
4555
4556 trace_ext4_allocate_blocks(ar, (unsigned long long)block);
4557
4558 return block;
4559}
4560
4561/*
4562 * We can merge two free data extents only if the physical blocks
4563 * are contiguous, AND the extents were freed by the same transaction,
4564 * AND the blocks are associated with the same group.
4565 */
4566static int can_merge(struct ext4_free_data *entry1,
4567 struct ext4_free_data *entry2)
4568{
4569 if ((entry1->efd_tid == entry2->efd_tid) &&
4570 (entry1->efd_group == entry2->efd_group) &&
4571 ((entry1->efd_start_cluster + entry1->efd_count) == entry2->efd_start_cluster))
4572 return 1;
4573 return 0;
4574}
4575
4576static noinline_for_stack int
4577ext4_mb_free_metadata(handle_t *handle, struct ext4_buddy *e4b,
4578 struct ext4_free_data *new_entry)
4579{
4580 ext4_group_t group = e4b->bd_group;
4581 ext4_grpblk_t cluster;
4582 struct ext4_free_data *entry;
4583 struct ext4_group_info *db = e4b->bd_info;
4584 struct super_block *sb = e4b->bd_sb;
4585 struct ext4_sb_info *sbi = EXT4_SB(sb);
4586 struct rb_node **n = &db->bb_free_root.rb_node, *node;
4587 struct rb_node *parent = NULL, *new_node;
4588
4589 BUG_ON(!ext4_handle_valid(handle));
4590 BUG_ON(e4b->bd_bitmap_page == NULL);
4591 BUG_ON(e4b->bd_buddy_page == NULL);
4592
4593 new_node = &new_entry->efd_node;
4594 cluster = new_entry->efd_start_cluster;
4595
4596 if (!*n) {
4597 /* first free block exent. We need to
4598 protect buddy cache from being freed,
4599 * otherwise we'll refresh it from
4600 * on-disk bitmap and lose not-yet-available
4601 * blocks */
4602 get_page(e4b->bd_buddy_page);
4603 get_page(e4b->bd_bitmap_page);
4604 }
4605 while (*n) {
4606 parent = *n;
4607 entry = rb_entry(parent, struct ext4_free_data, efd_node);
4608 if (cluster < entry->efd_start_cluster)
4609 n = &(*n)->rb_left;
4610 else if (cluster >= (entry->efd_start_cluster + entry->efd_count))
4611 n = &(*n)->rb_right;
4612 else {
4613 ext4_grp_locked_error(sb, group, 0,
4614 ext4_group_first_block_no(sb, group) +
4615 EXT4_C2B(sbi, cluster),
4616 "Block already on to-be-freed list");
4617 return 0;
4618 }
4619 }
4620
4621 rb_link_node(new_node, parent, n);
4622 rb_insert_color(new_node, &db->bb_free_root);
4623
4624 /* Now try to see the extent can be merged to left and right */
4625 node = rb_prev(new_node);
4626 if (node) {
4627 entry = rb_entry(node, struct ext4_free_data, efd_node);
4628 if (can_merge(entry, new_entry) &&
4629 ext4_journal_callback_try_del(handle, &entry->efd_jce)) {
4630 new_entry->efd_start_cluster = entry->efd_start_cluster;
4631 new_entry->efd_count += entry->efd_count;
4632 rb_erase(node, &(db->bb_free_root));
4633 kmem_cache_free(ext4_free_data_cachep, entry);
4634 }
4635 }
4636
4637 node = rb_next(new_node);
4638 if (node) {
4639 entry = rb_entry(node, struct ext4_free_data, efd_node);
4640 if (can_merge(new_entry, entry) &&
4641 ext4_journal_callback_try_del(handle, &entry->efd_jce)) {
4642 new_entry->efd_count += entry->efd_count;
4643 rb_erase(node, &(db->bb_free_root));
4644 kmem_cache_free(ext4_free_data_cachep, entry);
4645 }
4646 }
4647 /* Add the extent to transaction's private list */
4648 ext4_journal_callback_add(handle, ext4_free_data_callback,
4649 &new_entry->efd_jce);
4650 return 0;
4651}
4652
4653/**
4654 * ext4_free_blocks() -- Free given blocks and update quota
4655 * @handle: handle for this transaction
4656 * @inode: inode
4657 * @block: start physical block to free
4658 * @count: number of blocks to count
4659 * @flags: flags used by ext4_free_blocks
4660 */
4661void ext4_free_blocks(handle_t *handle, struct inode *inode,
4662 struct buffer_head *bh, ext4_fsblk_t block,
4663 unsigned long count, int flags)
4664{
4665 struct buffer_head *bitmap_bh = NULL;
4666 struct super_block *sb = inode->i_sb;
4667 struct ext4_group_desc *gdp;
4668 unsigned int overflow;
4669 ext4_grpblk_t bit;
4670 struct buffer_head *gd_bh;
4671 ext4_group_t block_group;
4672 struct ext4_sb_info *sbi;
4673 struct ext4_buddy e4b;
4674 unsigned int count_clusters;
4675 int err = 0;
4676 int ret;
4677
4678 might_sleep();
4679 if (bh) {
4680 if (block)
4681 BUG_ON(block != bh->b_blocknr);
4682 else
4683 block = bh->b_blocknr;
4684 }
4685
4686 sbi = EXT4_SB(sb);
4687 if (!(flags & EXT4_FREE_BLOCKS_VALIDATED) &&
4688 !ext4_data_block_valid(sbi, block, count)) {
4689 ext4_error(sb, "Freeing blocks not in datazone - "
4690 "block = %llu, count = %lu", block, count);
4691 goto error_return;
4692 }
4693
4694 ext4_debug("freeing block %llu\n", block);
4695 trace_ext4_free_blocks(inode, block, count, flags);
4696
4697 if (bh && (flags & EXT4_FREE_BLOCKS_FORGET)) {
4698 BUG_ON(count > 1);
4699
4700 ext4_forget(handle, flags & EXT4_FREE_BLOCKS_METADATA,
4701 inode, bh, block);
4702 }
4703
4704 /*
4705 * If the extent to be freed does not begin on a cluster
4706 * boundary, we need to deal with partial clusters at the
4707 * beginning and end of the extent. Normally we will free
4708 * blocks at the beginning or the end unless we are explicitly
4709 * requested to avoid doing so.
4710 */
4711 overflow = EXT4_PBLK_COFF(sbi, block);
4712 if (overflow) {
4713 if (flags & EXT4_FREE_BLOCKS_NOFREE_FIRST_CLUSTER) {
4714 overflow = sbi->s_cluster_ratio - overflow;
4715 block += overflow;
4716 if (count > overflow)
4717 count -= overflow;
4718 else
4719 return;
4720 } else {
4721 block -= overflow;
4722 count += overflow;
4723 }
4724 }
4725 overflow = EXT4_LBLK_COFF(sbi, count);
4726 if (overflow) {
4727 if (flags & EXT4_FREE_BLOCKS_NOFREE_LAST_CLUSTER) {
4728 if (count > overflow)
4729 count -= overflow;
4730 else
4731 return;
4732 } else
4733 count += sbi->s_cluster_ratio - overflow;
4734 }
4735
4736 if (!bh && (flags & EXT4_FREE_BLOCKS_FORGET)) {
4737 int i;
4738 int is_metadata = flags & EXT4_FREE_BLOCKS_METADATA;
4739
4740 for (i = 0; i < count; i++) {
4741 cond_resched();
4742 if (is_metadata)
4743 bh = sb_find_get_block(inode->i_sb, block + i);
4744 ext4_forget(handle, is_metadata, inode, bh, block + i);
4745 }
4746 }
4747
4748do_more:
4749 overflow = 0;
4750 ext4_get_group_no_and_offset(sb, block, &block_group, &bit);
4751
4752 if (unlikely(EXT4_MB_GRP_BBITMAP_CORRUPT(
4753 ext4_get_group_info(sb, block_group))))
4754 return;
4755
4756 /*
4757 * Check to see if we are freeing blocks across a group
4758 * boundary.
4759 */
4760 if (EXT4_C2B(sbi, bit) + count > EXT4_BLOCKS_PER_GROUP(sb)) {
4761 overflow = EXT4_C2B(sbi, bit) + count -
4762 EXT4_BLOCKS_PER_GROUP(sb);
4763 count -= overflow;
4764 }
4765 count_clusters = EXT4_NUM_B2C(sbi, count);
4766 bitmap_bh = ext4_read_block_bitmap(sb, block_group);
4767 if (IS_ERR(bitmap_bh)) {
4768 err = PTR_ERR(bitmap_bh);
4769 bitmap_bh = NULL;
4770 goto error_return;
4771 }
4772 gdp = ext4_get_group_desc(sb, block_group, &gd_bh);
4773 if (!gdp) {
4774 err = -EIO;
4775 goto error_return;
4776 }
4777
4778 if (in_range(ext4_block_bitmap(sb, gdp), block, count) ||
4779 in_range(ext4_inode_bitmap(sb, gdp), block, count) ||
4780 in_range(block, ext4_inode_table(sb, gdp),
4781 EXT4_SB(sb)->s_itb_per_group) ||
4782 in_range(block + count - 1, ext4_inode_table(sb, gdp),
4783 EXT4_SB(sb)->s_itb_per_group)) {
4784
4785 ext4_error(sb, "Freeing blocks in system zone - "
4786 "Block = %llu, count = %lu", block, count);
4787 /* err = 0. ext4_std_error should be a no op */
4788 goto error_return;
4789 }
4790
4791 BUFFER_TRACE(bitmap_bh, "getting write access");
4792 err = ext4_journal_get_write_access(handle, bitmap_bh);
4793 if (err)
4794 goto error_return;
4795
4796 /*
4797 * We are about to modify some metadata. Call the journal APIs
4798 * to unshare ->b_data if a currently-committing transaction is
4799 * using it
4800 */
4801 BUFFER_TRACE(gd_bh, "get_write_access");
4802 err = ext4_journal_get_write_access(handle, gd_bh);
4803 if (err)
4804 goto error_return;
4805#ifdef AGGRESSIVE_CHECK
4806 {
4807 int i;
4808 for (i = 0; i < count_clusters; i++)
4809 BUG_ON(!mb_test_bit(bit + i, bitmap_bh->b_data));
4810 }
4811#endif
4812 trace_ext4_mballoc_free(sb, inode, block_group, bit, count_clusters);
4813
4814 /* __GFP_NOFAIL: retry infinitely, ignore TIF_MEMDIE and memcg limit. */
4815 err = ext4_mb_load_buddy_gfp(sb, block_group, &e4b,
4816 GFP_NOFS|__GFP_NOFAIL);
4817 if (err)
4818 goto error_return;
4819
4820 /*
4821 * We need to make sure we don't reuse the freed block until after the
4822 * transaction is committed. We make an exception if the inode is to be
4823 * written in writeback mode since writeback mode has weak data
4824 * consistency guarantees.
4825 */
4826 if (ext4_handle_valid(handle) &&
4827 ((flags & EXT4_FREE_BLOCKS_METADATA) ||
4828 !ext4_should_writeback_data(inode))) {
4829 struct ext4_free_data *new_entry;
4830 /*
4831 * We use __GFP_NOFAIL because ext4_free_blocks() is not allowed
4832 * to fail.
4833 */
4834 new_entry = kmem_cache_alloc(ext4_free_data_cachep,
4835 GFP_NOFS|__GFP_NOFAIL);
4836 new_entry->efd_start_cluster = bit;
4837 new_entry->efd_group = block_group;
4838 new_entry->efd_count = count_clusters;
4839 new_entry->efd_tid = handle->h_transaction->t_tid;
4840
4841 ext4_lock_group(sb, block_group);
4842 mb_clear_bits(bitmap_bh->b_data, bit, count_clusters);
4843 ext4_mb_free_metadata(handle, &e4b, new_entry);
4844 } else {
4845 /* need to update group_info->bb_free and bitmap
4846 * with group lock held. generate_buddy look at
4847 * them with group lock_held
4848 */
4849 if (test_opt(sb, DISCARD)) {
4850 err = ext4_issue_discard(sb, block_group, bit, count);
4851 if (err && err != -EOPNOTSUPP)
4852 ext4_msg(sb, KERN_WARNING, "discard request in"
4853 " group:%d block:%d count:%lu failed"
4854 " with %d", block_group, bit, count,
4855 err);
4856 } else
4857 EXT4_MB_GRP_CLEAR_TRIMMED(e4b.bd_info);
4858
4859 ext4_lock_group(sb, block_group);
4860 mb_clear_bits(bitmap_bh->b_data, bit, count_clusters);
4861 mb_free_blocks(inode, &e4b, bit, count_clusters);
4862 }
4863
4864 ret = ext4_free_group_clusters(sb, gdp) + count_clusters;
4865 ext4_free_group_clusters_set(sb, gdp, ret);
4866 ext4_block_bitmap_csum_set(sb, block_group, gdp, bitmap_bh);
4867 ext4_group_desc_csum_set(sb, block_group, gdp);
4868 ext4_unlock_group(sb, block_group);
4869
4870 if (sbi->s_log_groups_per_flex) {
4871 ext4_group_t flex_group = ext4_flex_group(sbi, block_group);
4872 atomic64_add(count_clusters,
4873 &sbi->s_flex_groups[flex_group].free_clusters);
4874 }
4875
4876 if (!(flags & EXT4_FREE_BLOCKS_NO_QUOT_UPDATE))
4877 dquot_free_block(inode, EXT4_C2B(sbi, count_clusters));
4878 percpu_counter_add(&sbi->s_freeclusters_counter, count_clusters);
4879
4880 ext4_mb_unload_buddy(&e4b);
4881
4882 /* We dirtied the bitmap block */
4883 BUFFER_TRACE(bitmap_bh, "dirtied bitmap block");
4884 err = ext4_handle_dirty_metadata(handle, NULL, bitmap_bh);
4885
4886 /* And the group descriptor block */
4887 BUFFER_TRACE(gd_bh, "dirtied group descriptor block");
4888 ret = ext4_handle_dirty_metadata(handle, NULL, gd_bh);
4889 if (!err)
4890 err = ret;
4891
4892 if (overflow && !err) {
4893 block += count;
4894 count = overflow;
4895 put_bh(bitmap_bh);
4896 goto do_more;
4897 }
4898error_return:
4899 brelse(bitmap_bh);
4900 ext4_std_error(sb, err);
4901 return;
4902}
4903
4904/**
4905 * ext4_group_add_blocks() -- Add given blocks to an existing group
4906 * @handle: handle to this transaction
4907 * @sb: super block
4908 * @block: start physical block to add to the block group
4909 * @count: number of blocks to free
4910 *
4911 * This marks the blocks as free in the bitmap and buddy.
4912 */
4913int ext4_group_add_blocks(handle_t *handle, struct super_block *sb,
4914 ext4_fsblk_t block, unsigned long count)
4915{
4916 struct buffer_head *bitmap_bh = NULL;
4917 struct buffer_head *gd_bh;
4918 ext4_group_t block_group;
4919 ext4_grpblk_t bit;
4920 unsigned int i;
4921 struct ext4_group_desc *desc;
4922 struct ext4_sb_info *sbi = EXT4_SB(sb);
4923 struct ext4_buddy e4b;
4924 int err = 0, ret, blk_free_count;
4925 ext4_grpblk_t blocks_freed;
4926
4927 ext4_debug("Adding block(s) %llu-%llu\n", block, block + count - 1);
4928
4929 if (count == 0)
4930 return 0;
4931
4932 ext4_get_group_no_and_offset(sb, block, &block_group, &bit);
4933 /*
4934 * Check to see if we are freeing blocks across a group
4935 * boundary.
4936 */
4937 if (bit + count > EXT4_BLOCKS_PER_GROUP(sb)) {
4938 ext4_warning(sb, "too much blocks added to group %u\n",
4939 block_group);
4940 err = -EINVAL;
4941 goto error_return;
4942 }
4943
4944 bitmap_bh = ext4_read_block_bitmap(sb, block_group);
4945 if (IS_ERR(bitmap_bh)) {
4946 err = PTR_ERR(bitmap_bh);
4947 bitmap_bh = NULL;
4948 goto error_return;
4949 }
4950
4951 desc = ext4_get_group_desc(sb, block_group, &gd_bh);
4952 if (!desc) {
4953 err = -EIO;
4954 goto error_return;
4955 }
4956
4957 if (in_range(ext4_block_bitmap(sb, desc), block, count) ||
4958 in_range(ext4_inode_bitmap(sb, desc), block, count) ||
4959 in_range(block, ext4_inode_table(sb, desc), sbi->s_itb_per_group) ||
4960 in_range(block + count - 1, ext4_inode_table(sb, desc),
4961 sbi->s_itb_per_group)) {
4962 ext4_error(sb, "Adding blocks in system zones - "
4963 "Block = %llu, count = %lu",
4964 block, count);
4965 err = -EINVAL;
4966 goto error_return;
4967 }
4968
4969 BUFFER_TRACE(bitmap_bh, "getting write access");
4970 err = ext4_journal_get_write_access(handle, bitmap_bh);
4971 if (err)
4972 goto error_return;
4973
4974 /*
4975 * We are about to modify some metadata. Call the journal APIs
4976 * to unshare ->b_data if a currently-committing transaction is
4977 * using it
4978 */
4979 BUFFER_TRACE(gd_bh, "get_write_access");
4980 err = ext4_journal_get_write_access(handle, gd_bh);
4981 if (err)
4982 goto error_return;
4983
4984 for (i = 0, blocks_freed = 0; i < count; i++) {
4985 BUFFER_TRACE(bitmap_bh, "clear bit");
4986 if (!mb_test_bit(bit + i, bitmap_bh->b_data)) {
4987 ext4_error(sb, "bit already cleared for block %llu",
4988 (ext4_fsblk_t)(block + i));
4989 BUFFER_TRACE(bitmap_bh, "bit already cleared");
4990 } else {
4991 blocks_freed++;
4992 }
4993 }
4994
4995 err = ext4_mb_load_buddy(sb, block_group, &e4b);
4996 if (err)
4997 goto error_return;
4998
4999 /*
5000 * need to update group_info->bb_free and bitmap
5001 * with group lock held. generate_buddy look at
5002 * them with group lock_held
5003 */
5004 ext4_lock_group(sb, block_group);
5005 mb_clear_bits(bitmap_bh->b_data, bit, count);
5006 mb_free_blocks(NULL, &e4b, bit, count);
5007 blk_free_count = blocks_freed + ext4_free_group_clusters(sb, desc);
5008 ext4_free_group_clusters_set(sb, desc, blk_free_count);
5009 ext4_block_bitmap_csum_set(sb, block_group, desc, bitmap_bh);
5010 ext4_group_desc_csum_set(sb, block_group, desc);
5011 ext4_unlock_group(sb, block_group);
5012 percpu_counter_add(&sbi->s_freeclusters_counter,
5013 EXT4_NUM_B2C(sbi, blocks_freed));
5014
5015 if (sbi->s_log_groups_per_flex) {
5016 ext4_group_t flex_group = ext4_flex_group(sbi, block_group);
5017 atomic64_add(EXT4_NUM_B2C(sbi, blocks_freed),
5018 &sbi->s_flex_groups[flex_group].free_clusters);
5019 }
5020
5021 ext4_mb_unload_buddy(&e4b);
5022
5023 /* We dirtied the bitmap block */
5024 BUFFER_TRACE(bitmap_bh, "dirtied bitmap block");
5025 err = ext4_handle_dirty_metadata(handle, NULL, bitmap_bh);
5026
5027 /* And the group descriptor block */
5028 BUFFER_TRACE(gd_bh, "dirtied group descriptor block");
5029 ret = ext4_handle_dirty_metadata(handle, NULL, gd_bh);
5030 if (!err)
5031 err = ret;
5032
5033error_return:
5034 brelse(bitmap_bh);
5035 ext4_std_error(sb, err);
5036 return err;
5037}
5038
5039/**
5040 * ext4_trim_extent -- function to TRIM one single free extent in the group
5041 * @sb: super block for the file system
5042 * @start: starting block of the free extent in the alloc. group
5043 * @count: number of blocks to TRIM
5044 * @group: alloc. group we are working with
5045 * @e4b: ext4 buddy for the group
5046 *
5047 * Trim "count" blocks starting at "start" in the "group". To assure that no
5048 * one will allocate those blocks, mark it as used in buddy bitmap. This must
5049 * be called with under the group lock.
5050 */
5051static int ext4_trim_extent(struct super_block *sb, int start, int count,
5052 ext4_group_t group, struct ext4_buddy *e4b)
5053__releases(bitlock)
5054__acquires(bitlock)
5055{
5056 struct ext4_free_extent ex;
5057 int ret = 0;
5058
5059 trace_ext4_trim_extent(sb, group, start, count);
5060
5061 assert_spin_locked(ext4_group_lock_ptr(sb, group));
5062
5063 ex.fe_start = start;
5064 ex.fe_group = group;
5065 ex.fe_len = count;
5066
5067 /*
5068 * Mark blocks used, so no one can reuse them while
5069 * being trimmed.
5070 */
5071 mb_mark_used(e4b, &ex);
5072 ext4_unlock_group(sb, group);
5073 ret = ext4_issue_discard(sb, group, start, count);
5074 ext4_lock_group(sb, group);
5075 mb_free_blocks(NULL, e4b, start, ex.fe_len);
5076 return ret;
5077}
5078
5079/**
5080 * ext4_trim_all_free -- function to trim all free space in alloc. group
5081 * @sb: super block for file system
5082 * @group: group to be trimmed
5083 * @start: first group block to examine
5084 * @max: last group block to examine
5085 * @minblocks: minimum extent block count
5086 *
5087 * ext4_trim_all_free walks through group's buddy bitmap searching for free
5088 * extents. When the free block is found, ext4_trim_extent is called to TRIM
5089 * the extent.
5090 *
5091 *
5092 * ext4_trim_all_free walks through group's block bitmap searching for free
5093 * extents. When the free extent is found, mark it as used in group buddy
5094 * bitmap. Then issue a TRIM command on this extent and free the extent in
5095 * the group buddy bitmap. This is done until whole group is scanned.
5096 */
5097static ext4_grpblk_t
5098ext4_trim_all_free(struct super_block *sb, ext4_group_t group,
5099 ext4_grpblk_t start, ext4_grpblk_t max,
5100 ext4_grpblk_t minblocks)
5101{
5102 void *bitmap;
5103 ext4_grpblk_t next, count = 0, free_count = 0;
5104 struct ext4_buddy e4b;
5105 int ret = 0;
5106
5107 trace_ext4_trim_all_free(sb, group, start, max);
5108
5109 ret = ext4_mb_load_buddy(sb, group, &e4b);
5110 if (ret) {
5111 ext4_error(sb, "Error in loading buddy "
5112 "information for %u", group);
5113 return ret;
5114 }
5115 bitmap = e4b.bd_bitmap;
5116
5117 ext4_lock_group(sb, group);
5118 if (EXT4_MB_GRP_WAS_TRIMMED(e4b.bd_info) &&
5119 minblocks >= atomic_read(&EXT4_SB(sb)->s_last_trim_minblks))
5120 goto out;
5121
5122 start = (e4b.bd_info->bb_first_free > start) ?
5123 e4b.bd_info->bb_first_free : start;
5124
5125 while (start <= max) {
5126 start = mb_find_next_zero_bit(bitmap, max + 1, start);
5127 if (start > max)
5128 break;
5129 next = mb_find_next_bit(bitmap, max + 1, start);
5130
5131 if ((next - start) >= minblocks) {
5132 ret = ext4_trim_extent(sb, start,
5133 next - start, group, &e4b);
5134 if (ret && ret != -EOPNOTSUPP)
5135 break;
5136 ret = 0;
5137 count += next - start;
5138 }
5139 free_count += next - start;
5140 start = next + 1;
5141
5142 if (fatal_signal_pending(current)) {
5143 count = -ERESTARTSYS;
5144 break;
5145 }
5146
5147 if (need_resched()) {
5148 ext4_unlock_group(sb, group);
5149 cond_resched();
5150 ext4_lock_group(sb, group);
5151 }
5152
5153 if ((e4b.bd_info->bb_free - free_count) < minblocks)
5154 break;
5155 }
5156
5157 if (!ret) {
5158 ret = count;
5159 EXT4_MB_GRP_SET_TRIMMED(e4b.bd_info);
5160 }
5161out:
5162 ext4_unlock_group(sb, group);
5163 ext4_mb_unload_buddy(&e4b);
5164
5165 ext4_debug("trimmed %d blocks in the group %d\n",
5166 count, group);
5167
5168 return ret;
5169}
5170
5171/**
5172 * ext4_trim_fs() -- trim ioctl handle function
5173 * @sb: superblock for filesystem
5174 * @range: fstrim_range structure
5175 *
5176 * start: First Byte to trim
5177 * len: number of Bytes to trim from start
5178 * minlen: minimum extent length in Bytes
5179 * ext4_trim_fs goes through all allocation groups containing Bytes from
5180 * start to start+len. For each such a group ext4_trim_all_free function
5181 * is invoked to trim all free space.
5182 */
5183int ext4_trim_fs(struct super_block *sb, struct fstrim_range *range)
5184{
5185 struct ext4_group_info *grp;
5186 ext4_group_t group, first_group, last_group;
5187 ext4_grpblk_t cnt = 0, first_cluster, last_cluster;
5188 uint64_t start, end, minlen, trimmed = 0;
5189 ext4_fsblk_t first_data_blk =
5190 le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block);
5191 ext4_fsblk_t max_blks = ext4_blocks_count(EXT4_SB(sb)->s_es);
5192 int ret = 0;
5193
5194 start = range->start >> sb->s_blocksize_bits;
5195 end = start + (range->len >> sb->s_blocksize_bits) - 1;
5196 minlen = EXT4_NUM_B2C(EXT4_SB(sb),
5197 range->minlen >> sb->s_blocksize_bits);
5198
5199 if (minlen > EXT4_CLUSTERS_PER_GROUP(sb) ||
5200 start >= max_blks ||
5201 range->len < sb->s_blocksize)
5202 return -EINVAL;
5203 if (end >= max_blks)
5204 end = max_blks - 1;
5205 if (end <= first_data_blk)
5206 goto out;
5207 if (start < first_data_blk)
5208 start = first_data_blk;
5209
5210 /* Determine first and last group to examine based on start and end */
5211 ext4_get_group_no_and_offset(sb, (ext4_fsblk_t) start,
5212 &first_group, &first_cluster);
5213 ext4_get_group_no_and_offset(sb, (ext4_fsblk_t) end,
5214 &last_group, &last_cluster);
5215
5216 /* end now represents the last cluster to discard in this group */
5217 end = EXT4_CLUSTERS_PER_GROUP(sb) - 1;
5218
5219 for (group = first_group; group <= last_group; group++) {
5220 grp = ext4_get_group_info(sb, group);
5221 /* We only do this if the grp has never been initialized */
5222 if (unlikely(EXT4_MB_GRP_NEED_INIT(grp))) {
5223 ret = ext4_mb_init_group(sb, group, GFP_NOFS);
5224 if (ret)
5225 break;
5226 }
5227
5228 /*
5229 * For all the groups except the last one, last cluster will
5230 * always be EXT4_CLUSTERS_PER_GROUP(sb)-1, so we only need to
5231 * change it for the last group, note that last_cluster is
5232 * already computed earlier by ext4_get_group_no_and_offset()
5233 */
5234 if (group == last_group)
5235 end = last_cluster;
5236
5237 if (grp->bb_free >= minlen) {
5238 cnt = ext4_trim_all_free(sb, group, first_cluster,
5239 end, minlen);
5240 if (cnt < 0) {
5241 ret = cnt;
5242 break;
5243 }
5244 trimmed += cnt;
5245 }
5246
5247 /*
5248 * For every group except the first one, we are sure
5249 * that the first cluster to discard will be cluster #0.
5250 */
5251 first_cluster = 0;
5252 }
5253
5254 if (!ret)
5255 atomic_set(&EXT4_SB(sb)->s_last_trim_minblks, minlen);
5256
5257out:
5258 range->len = EXT4_C2B(EXT4_SB(sb), trimmed) << sb->s_blocksize_bits;
5259 return ret;
5260}
1/*
2 * Copyright (c) 2003-2006, Cluster File Systems, Inc, info@clusterfs.com
3 * Written by Alex Tomas <alex@clusterfs.com>
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License version 2 as
7 * published by the Free Software Foundation.
8 *
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write to the Free Software
16 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-
17 */
18
19
20/*
21 * mballoc.c contains the multiblocks allocation routines
22 */
23
24#include "ext4_jbd2.h"
25#include "mballoc.h"
26#include <linux/log2.h>
27#include <linux/module.h>
28#include <linux/slab.h>
29#include <linux/backing-dev.h>
30#include <trace/events/ext4.h>
31
32#ifdef CONFIG_EXT4_DEBUG
33ushort ext4_mballoc_debug __read_mostly;
34
35module_param_named(mballoc_debug, ext4_mballoc_debug, ushort, 0644);
36MODULE_PARM_DESC(mballoc_debug, "Debugging level for ext4's mballoc");
37#endif
38
39/*
40 * MUSTDO:
41 * - test ext4_ext_search_left() and ext4_ext_search_right()
42 * - search for metadata in few groups
43 *
44 * TODO v4:
45 * - normalization should take into account whether file is still open
46 * - discard preallocations if no free space left (policy?)
47 * - don't normalize tails
48 * - quota
49 * - reservation for superuser
50 *
51 * TODO v3:
52 * - bitmap read-ahead (proposed by Oleg Drokin aka green)
53 * - track min/max extents in each group for better group selection
54 * - mb_mark_used() may allocate chunk right after splitting buddy
55 * - tree of groups sorted by number of free blocks
56 * - error handling
57 */
58
59/*
60 * The allocation request involve request for multiple number of blocks
61 * near to the goal(block) value specified.
62 *
63 * During initialization phase of the allocator we decide to use the
64 * group preallocation or inode preallocation depending on the size of
65 * the file. The size of the file could be the resulting file size we
66 * would have after allocation, or the current file size, which ever
67 * is larger. If the size is less than sbi->s_mb_stream_request we
68 * select to use the group preallocation. The default value of
69 * s_mb_stream_request is 16 blocks. This can also be tuned via
70 * /sys/fs/ext4/<partition>/mb_stream_req. The value is represented in
71 * terms of number of blocks.
72 *
73 * The main motivation for having small file use group preallocation is to
74 * ensure that we have small files closer together on the disk.
75 *
76 * First stage the allocator looks at the inode prealloc list,
77 * ext4_inode_info->i_prealloc_list, which contains list of prealloc
78 * spaces for this particular inode. The inode prealloc space is
79 * represented as:
80 *
81 * pa_lstart -> the logical start block for this prealloc space
82 * pa_pstart -> the physical start block for this prealloc space
83 * pa_len -> length for this prealloc space (in clusters)
84 * pa_free -> free space available in this prealloc space (in clusters)
85 *
86 * The inode preallocation space is used looking at the _logical_ start
87 * block. If only the logical file block falls within the range of prealloc
88 * space we will consume the particular prealloc space. This makes sure that
89 * we have contiguous physical blocks representing the file blocks
90 *
91 * The important thing to be noted in case of inode prealloc space is that
92 * we don't modify the values associated to inode prealloc space except
93 * pa_free.
94 *
95 * If we are not able to find blocks in the inode prealloc space and if we
96 * have the group allocation flag set then we look at the locality group
97 * prealloc space. These are per CPU prealloc list represented as
98 *
99 * ext4_sb_info.s_locality_groups[smp_processor_id()]
100 *
101 * The reason for having a per cpu locality group is to reduce the contention
102 * between CPUs. It is possible to get scheduled at this point.
103 *
104 * The locality group prealloc space is used looking at whether we have
105 * enough free space (pa_free) within the prealloc space.
106 *
107 * If we can't allocate blocks via inode prealloc or/and locality group
108 * prealloc then we look at the buddy cache. The buddy cache is represented
109 * by ext4_sb_info.s_buddy_cache (struct inode) whose file offset gets
110 * mapped to the buddy and bitmap information regarding different
111 * groups. The buddy information is attached to buddy cache inode so that
112 * we can access them through the page cache. The information regarding
113 * each group is loaded via ext4_mb_load_buddy. The information involve
114 * block bitmap and buddy information. The information are stored in the
115 * inode as:
116 *
117 * { page }
118 * [ group 0 bitmap][ group 0 buddy] [group 1][ group 1]...
119 *
120 *
121 * one block each for bitmap and buddy information. So for each group we
122 * take up 2 blocks. A page can contain blocks_per_page (PAGE_SIZE /
123 * blocksize) blocks. So it can have information regarding groups_per_page
124 * which is blocks_per_page/2
125 *
126 * The buddy cache inode is not stored on disk. The inode is thrown
127 * away when the filesystem is unmounted.
128 *
129 * We look for count number of blocks in the buddy cache. If we were able
130 * to locate that many free blocks we return with additional information
131 * regarding rest of the contiguous physical block available
132 *
133 * Before allocating blocks via buddy cache we normalize the request
134 * blocks. This ensure we ask for more blocks that we needed. The extra
135 * blocks that we get after allocation is added to the respective prealloc
136 * list. In case of inode preallocation we follow a list of heuristics
137 * based on file size. This can be found in ext4_mb_normalize_request. If
138 * we are doing a group prealloc we try to normalize the request to
139 * sbi->s_mb_group_prealloc. The default value of s_mb_group_prealloc is
140 * dependent on the cluster size; for non-bigalloc file systems, it is
141 * 512 blocks. This can be tuned via
142 * /sys/fs/ext4/<partition>/mb_group_prealloc. The value is represented in
143 * terms of number of blocks. If we have mounted the file system with -O
144 * stripe=<value> option the group prealloc request is normalized to the
145 * the smallest multiple of the stripe value (sbi->s_stripe) which is
146 * greater than the default mb_group_prealloc.
147 *
148 * The regular allocator (using the buddy cache) supports a few tunables.
149 *
150 * /sys/fs/ext4/<partition>/mb_min_to_scan
151 * /sys/fs/ext4/<partition>/mb_max_to_scan
152 * /sys/fs/ext4/<partition>/mb_order2_req
153 *
154 * The regular allocator uses buddy scan only if the request len is power of
155 * 2 blocks and the order of allocation is >= sbi->s_mb_order2_reqs. The
156 * value of s_mb_order2_reqs can be tuned via
157 * /sys/fs/ext4/<partition>/mb_order2_req. If the request len is equal to
158 * stripe size (sbi->s_stripe), we try to search for contiguous block in
159 * stripe size. This should result in better allocation on RAID setups. If
160 * not, we search in the specific group using bitmap for best extents. The
161 * tunable min_to_scan and max_to_scan control the behaviour here.
162 * min_to_scan indicate how long the mballoc __must__ look for a best
163 * extent and max_to_scan indicates how long the mballoc __can__ look for a
164 * best extent in the found extents. Searching for the blocks starts with
165 * the group specified as the goal value in allocation context via
166 * ac_g_ex. Each group is first checked based on the criteria whether it
167 * can be used for allocation. ext4_mb_good_group explains how the groups are
168 * checked.
169 *
170 * Both the prealloc space are getting populated as above. So for the first
171 * request we will hit the buddy cache which will result in this prealloc
172 * space getting filled. The prealloc space is then later used for the
173 * subsequent request.
174 */
175
176/*
177 * mballoc operates on the following data:
178 * - on-disk bitmap
179 * - in-core buddy (actually includes buddy and bitmap)
180 * - preallocation descriptors (PAs)
181 *
182 * there are two types of preallocations:
183 * - inode
184 * assiged to specific inode and can be used for this inode only.
185 * it describes part of inode's space preallocated to specific
186 * physical blocks. any block from that preallocated can be used
187 * independent. the descriptor just tracks number of blocks left
188 * unused. so, before taking some block from descriptor, one must
189 * make sure corresponded logical block isn't allocated yet. this
190 * also means that freeing any block within descriptor's range
191 * must discard all preallocated blocks.
192 * - locality group
193 * assigned to specific locality group which does not translate to
194 * permanent set of inodes: inode can join and leave group. space
195 * from this type of preallocation can be used for any inode. thus
196 * it's consumed from the beginning to the end.
197 *
198 * relation between them can be expressed as:
199 * in-core buddy = on-disk bitmap + preallocation descriptors
200 *
201 * this mean blocks mballoc considers used are:
202 * - allocated blocks (persistent)
203 * - preallocated blocks (non-persistent)
204 *
205 * consistency in mballoc world means that at any time a block is either
206 * free or used in ALL structures. notice: "any time" should not be read
207 * literally -- time is discrete and delimited by locks.
208 *
209 * to keep it simple, we don't use block numbers, instead we count number of
210 * blocks: how many blocks marked used/free in on-disk bitmap, buddy and PA.
211 *
212 * all operations can be expressed as:
213 * - init buddy: buddy = on-disk + PAs
214 * - new PA: buddy += N; PA = N
215 * - use inode PA: on-disk += N; PA -= N
216 * - discard inode PA buddy -= on-disk - PA; PA = 0
217 * - use locality group PA on-disk += N; PA -= N
218 * - discard locality group PA buddy -= PA; PA = 0
219 * note: 'buddy -= on-disk - PA' is used to show that on-disk bitmap
220 * is used in real operation because we can't know actual used
221 * bits from PA, only from on-disk bitmap
222 *
223 * if we follow this strict logic, then all operations above should be atomic.
224 * given some of them can block, we'd have to use something like semaphores
225 * killing performance on high-end SMP hardware. let's try to relax it using
226 * the following knowledge:
227 * 1) if buddy is referenced, it's already initialized
228 * 2) while block is used in buddy and the buddy is referenced,
229 * nobody can re-allocate that block
230 * 3) we work on bitmaps and '+' actually means 'set bits'. if on-disk has
231 * bit set and PA claims same block, it's OK. IOW, one can set bit in
232 * on-disk bitmap if buddy has same bit set or/and PA covers corresponded
233 * block
234 *
235 * so, now we're building a concurrency table:
236 * - init buddy vs.
237 * - new PA
238 * blocks for PA are allocated in the buddy, buddy must be referenced
239 * until PA is linked to allocation group to avoid concurrent buddy init
240 * - use inode PA
241 * we need to make sure that either on-disk bitmap or PA has uptodate data
242 * given (3) we care that PA-=N operation doesn't interfere with init
243 * - discard inode PA
244 * the simplest way would be to have buddy initialized by the discard
245 * - use locality group PA
246 * again PA-=N must be serialized with init
247 * - discard locality group PA
248 * the simplest way would be to have buddy initialized by the discard
249 * - new PA vs.
250 * - use inode PA
251 * i_data_sem serializes them
252 * - discard inode PA
253 * discard process must wait until PA isn't used by another process
254 * - use locality group PA
255 * some mutex should serialize them
256 * - discard locality group PA
257 * discard process must wait until PA isn't used by another process
258 * - use inode PA
259 * - use inode PA
260 * i_data_sem or another mutex should serializes them
261 * - discard inode PA
262 * discard process must wait until PA isn't used by another process
263 * - use locality group PA
264 * nothing wrong here -- they're different PAs covering different blocks
265 * - discard locality group PA
266 * discard process must wait until PA isn't used by another process
267 *
268 * now we're ready to make few consequences:
269 * - PA is referenced and while it is no discard is possible
270 * - PA is referenced until block isn't marked in on-disk bitmap
271 * - PA changes only after on-disk bitmap
272 * - discard must not compete with init. either init is done before
273 * any discard or they're serialized somehow
274 * - buddy init as sum of on-disk bitmap and PAs is done atomically
275 *
276 * a special case when we've used PA to emptiness. no need to modify buddy
277 * in this case, but we should care about concurrent init
278 *
279 */
280
281 /*
282 * Logic in few words:
283 *
284 * - allocation:
285 * load group
286 * find blocks
287 * mark bits in on-disk bitmap
288 * release group
289 *
290 * - use preallocation:
291 * find proper PA (per-inode or group)
292 * load group
293 * mark bits in on-disk bitmap
294 * release group
295 * release PA
296 *
297 * - free:
298 * load group
299 * mark bits in on-disk bitmap
300 * release group
301 *
302 * - discard preallocations in group:
303 * mark PAs deleted
304 * move them onto local list
305 * load on-disk bitmap
306 * load group
307 * remove PA from object (inode or locality group)
308 * mark free blocks in-core
309 *
310 * - discard inode's preallocations:
311 */
312
313/*
314 * Locking rules
315 *
316 * Locks:
317 * - bitlock on a group (group)
318 * - object (inode/locality) (object)
319 * - per-pa lock (pa)
320 *
321 * Paths:
322 * - new pa
323 * object
324 * group
325 *
326 * - find and use pa:
327 * pa
328 *
329 * - release consumed pa:
330 * pa
331 * group
332 * object
333 *
334 * - generate in-core bitmap:
335 * group
336 * pa
337 *
338 * - discard all for given object (inode, locality group):
339 * object
340 * pa
341 * group
342 *
343 * - discard all for given group:
344 * group
345 * pa
346 * group
347 * object
348 *
349 */
350static struct kmem_cache *ext4_pspace_cachep;
351static struct kmem_cache *ext4_ac_cachep;
352static struct kmem_cache *ext4_free_data_cachep;
353
354/* We create slab caches for groupinfo data structures based on the
355 * superblock block size. There will be one per mounted filesystem for
356 * each unique s_blocksize_bits */
357#define NR_GRPINFO_CACHES 8
358static struct kmem_cache *ext4_groupinfo_caches[NR_GRPINFO_CACHES];
359
360static const char *ext4_groupinfo_slab_names[NR_GRPINFO_CACHES] = {
361 "ext4_groupinfo_1k", "ext4_groupinfo_2k", "ext4_groupinfo_4k",
362 "ext4_groupinfo_8k", "ext4_groupinfo_16k", "ext4_groupinfo_32k",
363 "ext4_groupinfo_64k", "ext4_groupinfo_128k"
364};
365
366static void ext4_mb_generate_from_pa(struct super_block *sb, void *bitmap,
367 ext4_group_t group);
368static void ext4_mb_generate_from_freelist(struct super_block *sb, void *bitmap,
369 ext4_group_t group);
370static void ext4_free_data_callback(struct super_block *sb,
371 struct ext4_journal_cb_entry *jce, int rc);
372
373static inline void *mb_correct_addr_and_bit(int *bit, void *addr)
374{
375#if BITS_PER_LONG == 64
376 *bit += ((unsigned long) addr & 7UL) << 3;
377 addr = (void *) ((unsigned long) addr & ~7UL);
378#elif BITS_PER_LONG == 32
379 *bit += ((unsigned long) addr & 3UL) << 3;
380 addr = (void *) ((unsigned long) addr & ~3UL);
381#else
382#error "how many bits you are?!"
383#endif
384 return addr;
385}
386
387static inline int mb_test_bit(int bit, void *addr)
388{
389 /*
390 * ext4_test_bit on architecture like powerpc
391 * needs unsigned long aligned address
392 */
393 addr = mb_correct_addr_and_bit(&bit, addr);
394 return ext4_test_bit(bit, addr);
395}
396
397static inline void mb_set_bit(int bit, void *addr)
398{
399 addr = mb_correct_addr_and_bit(&bit, addr);
400 ext4_set_bit(bit, addr);
401}
402
403static inline void mb_clear_bit(int bit, void *addr)
404{
405 addr = mb_correct_addr_and_bit(&bit, addr);
406 ext4_clear_bit(bit, addr);
407}
408
409static inline int mb_test_and_clear_bit(int bit, void *addr)
410{
411 addr = mb_correct_addr_and_bit(&bit, addr);
412 return ext4_test_and_clear_bit(bit, addr);
413}
414
415static inline int mb_find_next_zero_bit(void *addr, int max, int start)
416{
417 int fix = 0, ret, tmpmax;
418 addr = mb_correct_addr_and_bit(&fix, addr);
419 tmpmax = max + fix;
420 start += fix;
421
422 ret = ext4_find_next_zero_bit(addr, tmpmax, start) - fix;
423 if (ret > max)
424 return max;
425 return ret;
426}
427
428static inline int mb_find_next_bit(void *addr, int max, int start)
429{
430 int fix = 0, ret, tmpmax;
431 addr = mb_correct_addr_and_bit(&fix, addr);
432 tmpmax = max + fix;
433 start += fix;
434
435 ret = ext4_find_next_bit(addr, tmpmax, start) - fix;
436 if (ret > max)
437 return max;
438 return ret;
439}
440
441static void *mb_find_buddy(struct ext4_buddy *e4b, int order, int *max)
442{
443 char *bb;
444
445 BUG_ON(e4b->bd_bitmap == e4b->bd_buddy);
446 BUG_ON(max == NULL);
447
448 if (order > e4b->bd_blkbits + 1) {
449 *max = 0;
450 return NULL;
451 }
452
453 /* at order 0 we see each particular block */
454 if (order == 0) {
455 *max = 1 << (e4b->bd_blkbits + 3);
456 return e4b->bd_bitmap;
457 }
458
459 bb = e4b->bd_buddy + EXT4_SB(e4b->bd_sb)->s_mb_offsets[order];
460 *max = EXT4_SB(e4b->bd_sb)->s_mb_maxs[order];
461
462 return bb;
463}
464
465#ifdef DOUBLE_CHECK
466static void mb_free_blocks_double(struct inode *inode, struct ext4_buddy *e4b,
467 int first, int count)
468{
469 int i;
470 struct super_block *sb = e4b->bd_sb;
471
472 if (unlikely(e4b->bd_info->bb_bitmap == NULL))
473 return;
474 assert_spin_locked(ext4_group_lock_ptr(sb, e4b->bd_group));
475 for (i = 0; i < count; i++) {
476 if (!mb_test_bit(first + i, e4b->bd_info->bb_bitmap)) {
477 ext4_fsblk_t blocknr;
478
479 blocknr = ext4_group_first_block_no(sb, e4b->bd_group);
480 blocknr += EXT4_C2B(EXT4_SB(sb), first + i);
481 ext4_grp_locked_error(sb, e4b->bd_group,
482 inode ? inode->i_ino : 0,
483 blocknr,
484 "freeing block already freed "
485 "(bit %u)",
486 first + i);
487 }
488 mb_clear_bit(first + i, e4b->bd_info->bb_bitmap);
489 }
490}
491
492static void mb_mark_used_double(struct ext4_buddy *e4b, int first, int count)
493{
494 int i;
495
496 if (unlikely(e4b->bd_info->bb_bitmap == NULL))
497 return;
498 assert_spin_locked(ext4_group_lock_ptr(e4b->bd_sb, e4b->bd_group));
499 for (i = 0; i < count; i++) {
500 BUG_ON(mb_test_bit(first + i, e4b->bd_info->bb_bitmap));
501 mb_set_bit(first + i, e4b->bd_info->bb_bitmap);
502 }
503}
504
505static void mb_cmp_bitmaps(struct ext4_buddy *e4b, void *bitmap)
506{
507 if (memcmp(e4b->bd_info->bb_bitmap, bitmap, e4b->bd_sb->s_blocksize)) {
508 unsigned char *b1, *b2;
509 int i;
510 b1 = (unsigned char *) e4b->bd_info->bb_bitmap;
511 b2 = (unsigned char *) bitmap;
512 for (i = 0; i < e4b->bd_sb->s_blocksize; i++) {
513 if (b1[i] != b2[i]) {
514 ext4_msg(e4b->bd_sb, KERN_ERR,
515 "corruption in group %u "
516 "at byte %u(%u): %x in copy != %x "
517 "on disk/prealloc",
518 e4b->bd_group, i, i * 8, b1[i], b2[i]);
519 BUG();
520 }
521 }
522 }
523}
524
525#else
526static inline void mb_free_blocks_double(struct inode *inode,
527 struct ext4_buddy *e4b, int first, int count)
528{
529 return;
530}
531static inline void mb_mark_used_double(struct ext4_buddy *e4b,
532 int first, int count)
533{
534 return;
535}
536static inline void mb_cmp_bitmaps(struct ext4_buddy *e4b, void *bitmap)
537{
538 return;
539}
540#endif
541
542#ifdef AGGRESSIVE_CHECK
543
544#define MB_CHECK_ASSERT(assert) \
545do { \
546 if (!(assert)) { \
547 printk(KERN_EMERG \
548 "Assertion failure in %s() at %s:%d: \"%s\"\n", \
549 function, file, line, # assert); \
550 BUG(); \
551 } \
552} while (0)
553
554static int __mb_check_buddy(struct ext4_buddy *e4b, char *file,
555 const char *function, int line)
556{
557 struct super_block *sb = e4b->bd_sb;
558 int order = e4b->bd_blkbits + 1;
559 int max;
560 int max2;
561 int i;
562 int j;
563 int k;
564 int count;
565 struct ext4_group_info *grp;
566 int fragments = 0;
567 int fstart;
568 struct list_head *cur;
569 void *buddy;
570 void *buddy2;
571
572 {
573 static int mb_check_counter;
574 if (mb_check_counter++ % 100 != 0)
575 return 0;
576 }
577
578 while (order > 1) {
579 buddy = mb_find_buddy(e4b, order, &max);
580 MB_CHECK_ASSERT(buddy);
581 buddy2 = mb_find_buddy(e4b, order - 1, &max2);
582 MB_CHECK_ASSERT(buddy2);
583 MB_CHECK_ASSERT(buddy != buddy2);
584 MB_CHECK_ASSERT(max * 2 == max2);
585
586 count = 0;
587 for (i = 0; i < max; i++) {
588
589 if (mb_test_bit(i, buddy)) {
590 /* only single bit in buddy2 may be 1 */
591 if (!mb_test_bit(i << 1, buddy2)) {
592 MB_CHECK_ASSERT(
593 mb_test_bit((i<<1)+1, buddy2));
594 } else if (!mb_test_bit((i << 1) + 1, buddy2)) {
595 MB_CHECK_ASSERT(
596 mb_test_bit(i << 1, buddy2));
597 }
598 continue;
599 }
600
601 /* both bits in buddy2 must be 1 */
602 MB_CHECK_ASSERT(mb_test_bit(i << 1, buddy2));
603 MB_CHECK_ASSERT(mb_test_bit((i << 1) + 1, buddy2));
604
605 for (j = 0; j < (1 << order); j++) {
606 k = (i * (1 << order)) + j;
607 MB_CHECK_ASSERT(
608 !mb_test_bit(k, e4b->bd_bitmap));
609 }
610 count++;
611 }
612 MB_CHECK_ASSERT(e4b->bd_info->bb_counters[order] == count);
613 order--;
614 }
615
616 fstart = -1;
617 buddy = mb_find_buddy(e4b, 0, &max);
618 for (i = 0; i < max; i++) {
619 if (!mb_test_bit(i, buddy)) {
620 MB_CHECK_ASSERT(i >= e4b->bd_info->bb_first_free);
621 if (fstart == -1) {
622 fragments++;
623 fstart = i;
624 }
625 continue;
626 }
627 fstart = -1;
628 /* check used bits only */
629 for (j = 0; j < e4b->bd_blkbits + 1; j++) {
630 buddy2 = mb_find_buddy(e4b, j, &max2);
631 k = i >> j;
632 MB_CHECK_ASSERT(k < max2);
633 MB_CHECK_ASSERT(mb_test_bit(k, buddy2));
634 }
635 }
636 MB_CHECK_ASSERT(!EXT4_MB_GRP_NEED_INIT(e4b->bd_info));
637 MB_CHECK_ASSERT(e4b->bd_info->bb_fragments == fragments);
638
639 grp = ext4_get_group_info(sb, e4b->bd_group);
640 list_for_each(cur, &grp->bb_prealloc_list) {
641 ext4_group_t groupnr;
642 struct ext4_prealloc_space *pa;
643 pa = list_entry(cur, struct ext4_prealloc_space, pa_group_list);
644 ext4_get_group_no_and_offset(sb, pa->pa_pstart, &groupnr, &k);
645 MB_CHECK_ASSERT(groupnr == e4b->bd_group);
646 for (i = 0; i < pa->pa_len; i++)
647 MB_CHECK_ASSERT(mb_test_bit(k + i, buddy));
648 }
649 return 0;
650}
651#undef MB_CHECK_ASSERT
652#define mb_check_buddy(e4b) __mb_check_buddy(e4b, \
653 __FILE__, __func__, __LINE__)
654#else
655#define mb_check_buddy(e4b)
656#endif
657
658/*
659 * Divide blocks started from @first with length @len into
660 * smaller chunks with power of 2 blocks.
661 * Clear the bits in bitmap which the blocks of the chunk(s) covered,
662 * then increase bb_counters[] for corresponded chunk size.
663 */
664static void ext4_mb_mark_free_simple(struct super_block *sb,
665 void *buddy, ext4_grpblk_t first, ext4_grpblk_t len,
666 struct ext4_group_info *grp)
667{
668 struct ext4_sb_info *sbi = EXT4_SB(sb);
669 ext4_grpblk_t min;
670 ext4_grpblk_t max;
671 ext4_grpblk_t chunk;
672 unsigned int border;
673
674 BUG_ON(len > EXT4_CLUSTERS_PER_GROUP(sb));
675
676 border = 2 << sb->s_blocksize_bits;
677
678 while (len > 0) {
679 /* find how many blocks can be covered since this position */
680 max = ffs(first | border) - 1;
681
682 /* find how many blocks of power 2 we need to mark */
683 min = fls(len) - 1;
684
685 if (max < min)
686 min = max;
687 chunk = 1 << min;
688
689 /* mark multiblock chunks only */
690 grp->bb_counters[min]++;
691 if (min > 0)
692 mb_clear_bit(first >> min,
693 buddy + sbi->s_mb_offsets[min]);
694
695 len -= chunk;
696 first += chunk;
697 }
698}
699
700/*
701 * Cache the order of the largest free extent we have available in this block
702 * group.
703 */
704static void
705mb_set_largest_free_order(struct super_block *sb, struct ext4_group_info *grp)
706{
707 int i;
708 int bits;
709
710 grp->bb_largest_free_order = -1; /* uninit */
711
712 bits = sb->s_blocksize_bits + 1;
713 for (i = bits; i >= 0; i--) {
714 if (grp->bb_counters[i] > 0) {
715 grp->bb_largest_free_order = i;
716 break;
717 }
718 }
719}
720
721static noinline_for_stack
722void ext4_mb_generate_buddy(struct super_block *sb,
723 void *buddy, void *bitmap, ext4_group_t group)
724{
725 struct ext4_group_info *grp = ext4_get_group_info(sb, group);
726 struct ext4_sb_info *sbi = EXT4_SB(sb);
727 ext4_grpblk_t max = EXT4_CLUSTERS_PER_GROUP(sb);
728 ext4_grpblk_t i = 0;
729 ext4_grpblk_t first;
730 ext4_grpblk_t len;
731 unsigned free = 0;
732 unsigned fragments = 0;
733 unsigned long long period = get_cycles();
734
735 /* initialize buddy from bitmap which is aggregation
736 * of on-disk bitmap and preallocations */
737 i = mb_find_next_zero_bit(bitmap, max, 0);
738 grp->bb_first_free = i;
739 while (i < max) {
740 fragments++;
741 first = i;
742 i = mb_find_next_bit(bitmap, max, i);
743 len = i - first;
744 free += len;
745 if (len > 1)
746 ext4_mb_mark_free_simple(sb, buddy, first, len, grp);
747 else
748 grp->bb_counters[0]++;
749 if (i < max)
750 i = mb_find_next_zero_bit(bitmap, max, i);
751 }
752 grp->bb_fragments = fragments;
753
754 if (free != grp->bb_free) {
755 ext4_grp_locked_error(sb, group, 0, 0,
756 "block bitmap and bg descriptor "
757 "inconsistent: %u vs %u free clusters",
758 free, grp->bb_free);
759 /*
760 * If we intend to continue, we consider group descriptor
761 * corrupt and update bb_free using bitmap value
762 */
763 grp->bb_free = free;
764 if (!EXT4_MB_GRP_BBITMAP_CORRUPT(grp))
765 percpu_counter_sub(&sbi->s_freeclusters_counter,
766 grp->bb_free);
767 set_bit(EXT4_GROUP_INFO_BBITMAP_CORRUPT_BIT, &grp->bb_state);
768 }
769 mb_set_largest_free_order(sb, grp);
770
771 clear_bit(EXT4_GROUP_INFO_NEED_INIT_BIT, &(grp->bb_state));
772
773 period = get_cycles() - period;
774 spin_lock(&EXT4_SB(sb)->s_bal_lock);
775 EXT4_SB(sb)->s_mb_buddies_generated++;
776 EXT4_SB(sb)->s_mb_generation_time += period;
777 spin_unlock(&EXT4_SB(sb)->s_bal_lock);
778}
779
780static void mb_regenerate_buddy(struct ext4_buddy *e4b)
781{
782 int count;
783 int order = 1;
784 void *buddy;
785
786 while ((buddy = mb_find_buddy(e4b, order++, &count))) {
787 ext4_set_bits(buddy, 0, count);
788 }
789 e4b->bd_info->bb_fragments = 0;
790 memset(e4b->bd_info->bb_counters, 0,
791 sizeof(*e4b->bd_info->bb_counters) *
792 (e4b->bd_sb->s_blocksize_bits + 2));
793
794 ext4_mb_generate_buddy(e4b->bd_sb, e4b->bd_buddy,
795 e4b->bd_bitmap, e4b->bd_group);
796}
797
798/* The buddy information is attached the buddy cache inode
799 * for convenience. The information regarding each group
800 * is loaded via ext4_mb_load_buddy. The information involve
801 * block bitmap and buddy information. The information are
802 * stored in the inode as
803 *
804 * { page }
805 * [ group 0 bitmap][ group 0 buddy] [group 1][ group 1]...
806 *
807 *
808 * one block each for bitmap and buddy information.
809 * So for each group we take up 2 blocks. A page can
810 * contain blocks_per_page (PAGE_SIZE / blocksize) blocks.
811 * So it can have information regarding groups_per_page which
812 * is blocks_per_page/2
813 *
814 * Locking note: This routine takes the block group lock of all groups
815 * for this page; do not hold this lock when calling this routine!
816 */
817
818static int ext4_mb_init_cache(struct page *page, char *incore, gfp_t gfp)
819{
820 ext4_group_t ngroups;
821 int blocksize;
822 int blocks_per_page;
823 int groups_per_page;
824 int err = 0;
825 int i;
826 ext4_group_t first_group, group;
827 int first_block;
828 struct super_block *sb;
829 struct buffer_head *bhs;
830 struct buffer_head **bh = NULL;
831 struct inode *inode;
832 char *data;
833 char *bitmap;
834 struct ext4_group_info *grinfo;
835
836 mb_debug(1, "init page %lu\n", page->index);
837
838 inode = page->mapping->host;
839 sb = inode->i_sb;
840 ngroups = ext4_get_groups_count(sb);
841 blocksize = 1 << inode->i_blkbits;
842 blocks_per_page = PAGE_SIZE / blocksize;
843
844 groups_per_page = blocks_per_page >> 1;
845 if (groups_per_page == 0)
846 groups_per_page = 1;
847
848 /* allocate buffer_heads to read bitmaps */
849 if (groups_per_page > 1) {
850 i = sizeof(struct buffer_head *) * groups_per_page;
851 bh = kzalloc(i, gfp);
852 if (bh == NULL) {
853 err = -ENOMEM;
854 goto out;
855 }
856 } else
857 bh = &bhs;
858
859 first_group = page->index * blocks_per_page / 2;
860
861 /* read all groups the page covers into the cache */
862 for (i = 0, group = first_group; i < groups_per_page; i++, group++) {
863 if (group >= ngroups)
864 break;
865
866 grinfo = ext4_get_group_info(sb, group);
867 /*
868 * If page is uptodate then we came here after online resize
869 * which added some new uninitialized group info structs, so
870 * we must skip all initialized uptodate buddies on the page,
871 * which may be currently in use by an allocating task.
872 */
873 if (PageUptodate(page) && !EXT4_MB_GRP_NEED_INIT(grinfo)) {
874 bh[i] = NULL;
875 continue;
876 }
877 bh[i] = ext4_read_block_bitmap_nowait(sb, group);
878 if (IS_ERR(bh[i])) {
879 err = PTR_ERR(bh[i]);
880 bh[i] = NULL;
881 goto out;
882 }
883 mb_debug(1, "read bitmap for group %u\n", group);
884 }
885
886 /* wait for I/O completion */
887 for (i = 0, group = first_group; i < groups_per_page; i++, group++) {
888 int err2;
889
890 if (!bh[i])
891 continue;
892 err2 = ext4_wait_block_bitmap(sb, group, bh[i]);
893 if (!err)
894 err = err2;
895 }
896
897 first_block = page->index * blocks_per_page;
898 for (i = 0; i < blocks_per_page; i++) {
899 group = (first_block + i) >> 1;
900 if (group >= ngroups)
901 break;
902
903 if (!bh[group - first_group])
904 /* skip initialized uptodate buddy */
905 continue;
906
907 if (!buffer_verified(bh[group - first_group]))
908 /* Skip faulty bitmaps */
909 continue;
910 err = 0;
911
912 /*
913 * data carry information regarding this
914 * particular group in the format specified
915 * above
916 *
917 */
918 data = page_address(page) + (i * blocksize);
919 bitmap = bh[group - first_group]->b_data;
920
921 /*
922 * We place the buddy block and bitmap block
923 * close together
924 */
925 if ((first_block + i) & 1) {
926 /* this is block of buddy */
927 BUG_ON(incore == NULL);
928 mb_debug(1, "put buddy for group %u in page %lu/%x\n",
929 group, page->index, i * blocksize);
930 trace_ext4_mb_buddy_bitmap_load(sb, group);
931 grinfo = ext4_get_group_info(sb, group);
932 grinfo->bb_fragments = 0;
933 memset(grinfo->bb_counters, 0,
934 sizeof(*grinfo->bb_counters) *
935 (sb->s_blocksize_bits+2));
936 /*
937 * incore got set to the group block bitmap below
938 */
939 ext4_lock_group(sb, group);
940 /* init the buddy */
941 memset(data, 0xff, blocksize);
942 ext4_mb_generate_buddy(sb, data, incore, group);
943 ext4_unlock_group(sb, group);
944 incore = NULL;
945 } else {
946 /* this is block of bitmap */
947 BUG_ON(incore != NULL);
948 mb_debug(1, "put bitmap for group %u in page %lu/%x\n",
949 group, page->index, i * blocksize);
950 trace_ext4_mb_bitmap_load(sb, group);
951
952 /* see comments in ext4_mb_put_pa() */
953 ext4_lock_group(sb, group);
954 memcpy(data, bitmap, blocksize);
955
956 /* mark all preallocated blks used in in-core bitmap */
957 ext4_mb_generate_from_pa(sb, data, group);
958 ext4_mb_generate_from_freelist(sb, data, group);
959 ext4_unlock_group(sb, group);
960
961 /* set incore so that the buddy information can be
962 * generated using this
963 */
964 incore = data;
965 }
966 }
967 SetPageUptodate(page);
968
969out:
970 if (bh) {
971 for (i = 0; i < groups_per_page; i++)
972 brelse(bh[i]);
973 if (bh != &bhs)
974 kfree(bh);
975 }
976 return err;
977}
978
979/*
980 * Lock the buddy and bitmap pages. This make sure other parallel init_group
981 * on the same buddy page doesn't happen whild holding the buddy page lock.
982 * Return locked buddy and bitmap pages on e4b struct. If buddy and bitmap
983 * are on the same page e4b->bd_buddy_page is NULL and return value is 0.
984 */
985static int ext4_mb_get_buddy_page_lock(struct super_block *sb,
986 ext4_group_t group, struct ext4_buddy *e4b, gfp_t gfp)
987{
988 struct inode *inode = EXT4_SB(sb)->s_buddy_cache;
989 int block, pnum, poff;
990 int blocks_per_page;
991 struct page *page;
992
993 e4b->bd_buddy_page = NULL;
994 e4b->bd_bitmap_page = NULL;
995
996 blocks_per_page = PAGE_SIZE / sb->s_blocksize;
997 /*
998 * the buddy cache inode stores the block bitmap
999 * and buddy information in consecutive blocks.
1000 * So for each group we need two blocks.
1001 */
1002 block = group * 2;
1003 pnum = block / blocks_per_page;
1004 poff = block % blocks_per_page;
1005 page = find_or_create_page(inode->i_mapping, pnum, gfp);
1006 if (!page)
1007 return -ENOMEM;
1008 BUG_ON(page->mapping != inode->i_mapping);
1009 e4b->bd_bitmap_page = page;
1010 e4b->bd_bitmap = page_address(page) + (poff * sb->s_blocksize);
1011
1012 if (blocks_per_page >= 2) {
1013 /* buddy and bitmap are on the same page */
1014 return 0;
1015 }
1016
1017 block++;
1018 pnum = block / blocks_per_page;
1019 page = find_or_create_page(inode->i_mapping, pnum, gfp);
1020 if (!page)
1021 return -ENOMEM;
1022 BUG_ON(page->mapping != inode->i_mapping);
1023 e4b->bd_buddy_page = page;
1024 return 0;
1025}
1026
1027static void ext4_mb_put_buddy_page_lock(struct ext4_buddy *e4b)
1028{
1029 if (e4b->bd_bitmap_page) {
1030 unlock_page(e4b->bd_bitmap_page);
1031 put_page(e4b->bd_bitmap_page);
1032 }
1033 if (e4b->bd_buddy_page) {
1034 unlock_page(e4b->bd_buddy_page);
1035 put_page(e4b->bd_buddy_page);
1036 }
1037}
1038
1039/*
1040 * Locking note: This routine calls ext4_mb_init_cache(), which takes the
1041 * block group lock of all groups for this page; do not hold the BG lock when
1042 * calling this routine!
1043 */
1044static noinline_for_stack
1045int ext4_mb_init_group(struct super_block *sb, ext4_group_t group, gfp_t gfp)
1046{
1047
1048 struct ext4_group_info *this_grp;
1049 struct ext4_buddy e4b;
1050 struct page *page;
1051 int ret = 0;
1052
1053 might_sleep();
1054 mb_debug(1, "init group %u\n", group);
1055 this_grp = ext4_get_group_info(sb, group);
1056 /*
1057 * This ensures that we don't reinit the buddy cache
1058 * page which map to the group from which we are already
1059 * allocating. If we are looking at the buddy cache we would
1060 * have taken a reference using ext4_mb_load_buddy and that
1061 * would have pinned buddy page to page cache.
1062 * The call to ext4_mb_get_buddy_page_lock will mark the
1063 * page accessed.
1064 */
1065 ret = ext4_mb_get_buddy_page_lock(sb, group, &e4b, gfp);
1066 if (ret || !EXT4_MB_GRP_NEED_INIT(this_grp)) {
1067 /*
1068 * somebody initialized the group
1069 * return without doing anything
1070 */
1071 goto err;
1072 }
1073
1074 page = e4b.bd_bitmap_page;
1075 ret = ext4_mb_init_cache(page, NULL, gfp);
1076 if (ret)
1077 goto err;
1078 if (!PageUptodate(page)) {
1079 ret = -EIO;
1080 goto err;
1081 }
1082
1083 if (e4b.bd_buddy_page == NULL) {
1084 /*
1085 * If both the bitmap and buddy are in
1086 * the same page we don't need to force
1087 * init the buddy
1088 */
1089 ret = 0;
1090 goto err;
1091 }
1092 /* init buddy cache */
1093 page = e4b.bd_buddy_page;
1094 ret = ext4_mb_init_cache(page, e4b.bd_bitmap, gfp);
1095 if (ret)
1096 goto err;
1097 if (!PageUptodate(page)) {
1098 ret = -EIO;
1099 goto err;
1100 }
1101err:
1102 ext4_mb_put_buddy_page_lock(&e4b);
1103 return ret;
1104}
1105
1106/*
1107 * Locking note: This routine calls ext4_mb_init_cache(), which takes the
1108 * block group lock of all groups for this page; do not hold the BG lock when
1109 * calling this routine!
1110 */
1111static noinline_for_stack int
1112ext4_mb_load_buddy_gfp(struct super_block *sb, ext4_group_t group,
1113 struct ext4_buddy *e4b, gfp_t gfp)
1114{
1115 int blocks_per_page;
1116 int block;
1117 int pnum;
1118 int poff;
1119 struct page *page;
1120 int ret;
1121 struct ext4_group_info *grp;
1122 struct ext4_sb_info *sbi = EXT4_SB(sb);
1123 struct inode *inode = sbi->s_buddy_cache;
1124
1125 might_sleep();
1126 mb_debug(1, "load group %u\n", group);
1127
1128 blocks_per_page = PAGE_SIZE / sb->s_blocksize;
1129 grp = ext4_get_group_info(sb, group);
1130
1131 e4b->bd_blkbits = sb->s_blocksize_bits;
1132 e4b->bd_info = grp;
1133 e4b->bd_sb = sb;
1134 e4b->bd_group = group;
1135 e4b->bd_buddy_page = NULL;
1136 e4b->bd_bitmap_page = NULL;
1137
1138 if (unlikely(EXT4_MB_GRP_NEED_INIT(grp))) {
1139 /*
1140 * we need full data about the group
1141 * to make a good selection
1142 */
1143 ret = ext4_mb_init_group(sb, group, gfp);
1144 if (ret)
1145 return ret;
1146 }
1147
1148 /*
1149 * the buddy cache inode stores the block bitmap
1150 * and buddy information in consecutive blocks.
1151 * So for each group we need two blocks.
1152 */
1153 block = group * 2;
1154 pnum = block / blocks_per_page;
1155 poff = block % blocks_per_page;
1156
1157 /* we could use find_or_create_page(), but it locks page
1158 * what we'd like to avoid in fast path ... */
1159 page = find_get_page_flags(inode->i_mapping, pnum, FGP_ACCESSED);
1160 if (page == NULL || !PageUptodate(page)) {
1161 if (page)
1162 /*
1163 * drop the page reference and try
1164 * to get the page with lock. If we
1165 * are not uptodate that implies
1166 * somebody just created the page but
1167 * is yet to initialize the same. So
1168 * wait for it to initialize.
1169 */
1170 put_page(page);
1171 page = find_or_create_page(inode->i_mapping, pnum, gfp);
1172 if (page) {
1173 BUG_ON(page->mapping != inode->i_mapping);
1174 if (!PageUptodate(page)) {
1175 ret = ext4_mb_init_cache(page, NULL, gfp);
1176 if (ret) {
1177 unlock_page(page);
1178 goto err;
1179 }
1180 mb_cmp_bitmaps(e4b, page_address(page) +
1181 (poff * sb->s_blocksize));
1182 }
1183 unlock_page(page);
1184 }
1185 }
1186 if (page == NULL) {
1187 ret = -ENOMEM;
1188 goto err;
1189 }
1190 if (!PageUptodate(page)) {
1191 ret = -EIO;
1192 goto err;
1193 }
1194
1195 /* Pages marked accessed already */
1196 e4b->bd_bitmap_page = page;
1197 e4b->bd_bitmap = page_address(page) + (poff * sb->s_blocksize);
1198
1199 block++;
1200 pnum = block / blocks_per_page;
1201 poff = block % blocks_per_page;
1202
1203 page = find_get_page_flags(inode->i_mapping, pnum, FGP_ACCESSED);
1204 if (page == NULL || !PageUptodate(page)) {
1205 if (page)
1206 put_page(page);
1207 page = find_or_create_page(inode->i_mapping, pnum, gfp);
1208 if (page) {
1209 BUG_ON(page->mapping != inode->i_mapping);
1210 if (!PageUptodate(page)) {
1211 ret = ext4_mb_init_cache(page, e4b->bd_bitmap,
1212 gfp);
1213 if (ret) {
1214 unlock_page(page);
1215 goto err;
1216 }
1217 }
1218 unlock_page(page);
1219 }
1220 }
1221 if (page == NULL) {
1222 ret = -ENOMEM;
1223 goto err;
1224 }
1225 if (!PageUptodate(page)) {
1226 ret = -EIO;
1227 goto err;
1228 }
1229
1230 /* Pages marked accessed already */
1231 e4b->bd_buddy_page = page;
1232 e4b->bd_buddy = page_address(page) + (poff * sb->s_blocksize);
1233
1234 BUG_ON(e4b->bd_bitmap_page == NULL);
1235 BUG_ON(e4b->bd_buddy_page == NULL);
1236
1237 return 0;
1238
1239err:
1240 if (page)
1241 put_page(page);
1242 if (e4b->bd_bitmap_page)
1243 put_page(e4b->bd_bitmap_page);
1244 if (e4b->bd_buddy_page)
1245 put_page(e4b->bd_buddy_page);
1246 e4b->bd_buddy = NULL;
1247 e4b->bd_bitmap = NULL;
1248 return ret;
1249}
1250
1251static int ext4_mb_load_buddy(struct super_block *sb, ext4_group_t group,
1252 struct ext4_buddy *e4b)
1253{
1254 return ext4_mb_load_buddy_gfp(sb, group, e4b, GFP_NOFS);
1255}
1256
1257static void ext4_mb_unload_buddy(struct ext4_buddy *e4b)
1258{
1259 if (e4b->bd_bitmap_page)
1260 put_page(e4b->bd_bitmap_page);
1261 if (e4b->bd_buddy_page)
1262 put_page(e4b->bd_buddy_page);
1263}
1264
1265
1266static int mb_find_order_for_block(struct ext4_buddy *e4b, int block)
1267{
1268 int order = 1;
1269 int bb_incr = 1 << (e4b->bd_blkbits - 1);
1270 void *bb;
1271
1272 BUG_ON(e4b->bd_bitmap == e4b->bd_buddy);
1273 BUG_ON(block >= (1 << (e4b->bd_blkbits + 3)));
1274
1275 bb = e4b->bd_buddy;
1276 while (order <= e4b->bd_blkbits + 1) {
1277 block = block >> 1;
1278 if (!mb_test_bit(block, bb)) {
1279 /* this block is part of buddy of order 'order' */
1280 return order;
1281 }
1282 bb += bb_incr;
1283 bb_incr >>= 1;
1284 order++;
1285 }
1286 return 0;
1287}
1288
1289static void mb_clear_bits(void *bm, int cur, int len)
1290{
1291 __u32 *addr;
1292
1293 len = cur + len;
1294 while (cur < len) {
1295 if ((cur & 31) == 0 && (len - cur) >= 32) {
1296 /* fast path: clear whole word at once */
1297 addr = bm + (cur >> 3);
1298 *addr = 0;
1299 cur += 32;
1300 continue;
1301 }
1302 mb_clear_bit(cur, bm);
1303 cur++;
1304 }
1305}
1306
1307/* clear bits in given range
1308 * will return first found zero bit if any, -1 otherwise
1309 */
1310static int mb_test_and_clear_bits(void *bm, int cur, int len)
1311{
1312 __u32 *addr;
1313 int zero_bit = -1;
1314
1315 len = cur + len;
1316 while (cur < len) {
1317 if ((cur & 31) == 0 && (len - cur) >= 32) {
1318 /* fast path: clear whole word at once */
1319 addr = bm + (cur >> 3);
1320 if (*addr != (__u32)(-1) && zero_bit == -1)
1321 zero_bit = cur + mb_find_next_zero_bit(addr, 32, 0);
1322 *addr = 0;
1323 cur += 32;
1324 continue;
1325 }
1326 if (!mb_test_and_clear_bit(cur, bm) && zero_bit == -1)
1327 zero_bit = cur;
1328 cur++;
1329 }
1330
1331 return zero_bit;
1332}
1333
1334void ext4_set_bits(void *bm, int cur, int len)
1335{
1336 __u32 *addr;
1337
1338 len = cur + len;
1339 while (cur < len) {
1340 if ((cur & 31) == 0 && (len - cur) >= 32) {
1341 /* fast path: set whole word at once */
1342 addr = bm + (cur >> 3);
1343 *addr = 0xffffffff;
1344 cur += 32;
1345 continue;
1346 }
1347 mb_set_bit(cur, bm);
1348 cur++;
1349 }
1350}
1351
1352/*
1353 * _________________________________________________________________ */
1354
1355static inline int mb_buddy_adjust_border(int* bit, void* bitmap, int side)
1356{
1357 if (mb_test_bit(*bit + side, bitmap)) {
1358 mb_clear_bit(*bit, bitmap);
1359 (*bit) -= side;
1360 return 1;
1361 }
1362 else {
1363 (*bit) += side;
1364 mb_set_bit(*bit, bitmap);
1365 return -1;
1366 }
1367}
1368
1369static void mb_buddy_mark_free(struct ext4_buddy *e4b, int first, int last)
1370{
1371 int max;
1372 int order = 1;
1373 void *buddy = mb_find_buddy(e4b, order, &max);
1374
1375 while (buddy) {
1376 void *buddy2;
1377
1378 /* Bits in range [first; last] are known to be set since
1379 * corresponding blocks were allocated. Bits in range
1380 * (first; last) will stay set because they form buddies on
1381 * upper layer. We just deal with borders if they don't
1382 * align with upper layer and then go up.
1383 * Releasing entire group is all about clearing
1384 * single bit of highest order buddy.
1385 */
1386
1387 /* Example:
1388 * ---------------------------------
1389 * | 1 | 1 | 1 | 1 |
1390 * ---------------------------------
1391 * | 0 | 1 | 1 | 1 | 1 | 1 | 1 | 1 |
1392 * ---------------------------------
1393 * 0 1 2 3 4 5 6 7
1394 * \_____________________/
1395 *
1396 * Neither [1] nor [6] is aligned to above layer.
1397 * Left neighbour [0] is free, so mark it busy,
1398 * decrease bb_counters and extend range to
1399 * [0; 6]
1400 * Right neighbour [7] is busy. It can't be coaleasced with [6], so
1401 * mark [6] free, increase bb_counters and shrink range to
1402 * [0; 5].
1403 * Then shift range to [0; 2], go up and do the same.
1404 */
1405
1406
1407 if (first & 1)
1408 e4b->bd_info->bb_counters[order] += mb_buddy_adjust_border(&first, buddy, -1);
1409 if (!(last & 1))
1410 e4b->bd_info->bb_counters[order] += mb_buddy_adjust_border(&last, buddy, 1);
1411 if (first > last)
1412 break;
1413 order++;
1414
1415 if (first == last || !(buddy2 = mb_find_buddy(e4b, order, &max))) {
1416 mb_clear_bits(buddy, first, last - first + 1);
1417 e4b->bd_info->bb_counters[order - 1] += last - first + 1;
1418 break;
1419 }
1420 first >>= 1;
1421 last >>= 1;
1422 buddy = buddy2;
1423 }
1424}
1425
1426static void mb_free_blocks(struct inode *inode, struct ext4_buddy *e4b,
1427 int first, int count)
1428{
1429 int left_is_free = 0;
1430 int right_is_free = 0;
1431 int block;
1432 int last = first + count - 1;
1433 struct super_block *sb = e4b->bd_sb;
1434
1435 if (WARN_ON(count == 0))
1436 return;
1437 BUG_ON(last >= (sb->s_blocksize << 3));
1438 assert_spin_locked(ext4_group_lock_ptr(sb, e4b->bd_group));
1439 /* Don't bother if the block group is corrupt. */
1440 if (unlikely(EXT4_MB_GRP_BBITMAP_CORRUPT(e4b->bd_info)))
1441 return;
1442
1443 mb_check_buddy(e4b);
1444 mb_free_blocks_double(inode, e4b, first, count);
1445
1446 e4b->bd_info->bb_free += count;
1447 if (first < e4b->bd_info->bb_first_free)
1448 e4b->bd_info->bb_first_free = first;
1449
1450 /* access memory sequentially: check left neighbour,
1451 * clear range and then check right neighbour
1452 */
1453 if (first != 0)
1454 left_is_free = !mb_test_bit(first - 1, e4b->bd_bitmap);
1455 block = mb_test_and_clear_bits(e4b->bd_bitmap, first, count);
1456 if (last + 1 < EXT4_SB(sb)->s_mb_maxs[0])
1457 right_is_free = !mb_test_bit(last + 1, e4b->bd_bitmap);
1458
1459 if (unlikely(block != -1)) {
1460 struct ext4_sb_info *sbi = EXT4_SB(sb);
1461 ext4_fsblk_t blocknr;
1462
1463 blocknr = ext4_group_first_block_no(sb, e4b->bd_group);
1464 blocknr += EXT4_C2B(EXT4_SB(sb), block);
1465 ext4_grp_locked_error(sb, e4b->bd_group,
1466 inode ? inode->i_ino : 0,
1467 blocknr,
1468 "freeing already freed block "
1469 "(bit %u); block bitmap corrupt.",
1470 block);
1471 if (!EXT4_MB_GRP_BBITMAP_CORRUPT(e4b->bd_info))
1472 percpu_counter_sub(&sbi->s_freeclusters_counter,
1473 e4b->bd_info->bb_free);
1474 /* Mark the block group as corrupt. */
1475 set_bit(EXT4_GROUP_INFO_BBITMAP_CORRUPT_BIT,
1476 &e4b->bd_info->bb_state);
1477 mb_regenerate_buddy(e4b);
1478 goto done;
1479 }
1480
1481 /* let's maintain fragments counter */
1482 if (left_is_free && right_is_free)
1483 e4b->bd_info->bb_fragments--;
1484 else if (!left_is_free && !right_is_free)
1485 e4b->bd_info->bb_fragments++;
1486
1487 /* buddy[0] == bd_bitmap is a special case, so handle
1488 * it right away and let mb_buddy_mark_free stay free of
1489 * zero order checks.
1490 * Check if neighbours are to be coaleasced,
1491 * adjust bitmap bb_counters and borders appropriately.
1492 */
1493 if (first & 1) {
1494 first += !left_is_free;
1495 e4b->bd_info->bb_counters[0] += left_is_free ? -1 : 1;
1496 }
1497 if (!(last & 1)) {
1498 last -= !right_is_free;
1499 e4b->bd_info->bb_counters[0] += right_is_free ? -1 : 1;
1500 }
1501
1502 if (first <= last)
1503 mb_buddy_mark_free(e4b, first >> 1, last >> 1);
1504
1505done:
1506 mb_set_largest_free_order(sb, e4b->bd_info);
1507 mb_check_buddy(e4b);
1508}
1509
1510static int mb_find_extent(struct ext4_buddy *e4b, int block,
1511 int needed, struct ext4_free_extent *ex)
1512{
1513 int next = block;
1514 int max, order;
1515 void *buddy;
1516
1517 assert_spin_locked(ext4_group_lock_ptr(e4b->bd_sb, e4b->bd_group));
1518 BUG_ON(ex == NULL);
1519
1520 buddy = mb_find_buddy(e4b, 0, &max);
1521 BUG_ON(buddy == NULL);
1522 BUG_ON(block >= max);
1523 if (mb_test_bit(block, buddy)) {
1524 ex->fe_len = 0;
1525 ex->fe_start = 0;
1526 ex->fe_group = 0;
1527 return 0;
1528 }
1529
1530 /* find actual order */
1531 order = mb_find_order_for_block(e4b, block);
1532 block = block >> order;
1533
1534 ex->fe_len = 1 << order;
1535 ex->fe_start = block << order;
1536 ex->fe_group = e4b->bd_group;
1537
1538 /* calc difference from given start */
1539 next = next - ex->fe_start;
1540 ex->fe_len -= next;
1541 ex->fe_start += next;
1542
1543 while (needed > ex->fe_len &&
1544 mb_find_buddy(e4b, order, &max)) {
1545
1546 if (block + 1 >= max)
1547 break;
1548
1549 next = (block + 1) * (1 << order);
1550 if (mb_test_bit(next, e4b->bd_bitmap))
1551 break;
1552
1553 order = mb_find_order_for_block(e4b, next);
1554
1555 block = next >> order;
1556 ex->fe_len += 1 << order;
1557 }
1558
1559 BUG_ON(ex->fe_start + ex->fe_len > (1 << (e4b->bd_blkbits + 3)));
1560 return ex->fe_len;
1561}
1562
1563static int mb_mark_used(struct ext4_buddy *e4b, struct ext4_free_extent *ex)
1564{
1565 int ord;
1566 int mlen = 0;
1567 int max = 0;
1568 int cur;
1569 int start = ex->fe_start;
1570 int len = ex->fe_len;
1571 unsigned ret = 0;
1572 int len0 = len;
1573 void *buddy;
1574
1575 BUG_ON(start + len > (e4b->bd_sb->s_blocksize << 3));
1576 BUG_ON(e4b->bd_group != ex->fe_group);
1577 assert_spin_locked(ext4_group_lock_ptr(e4b->bd_sb, e4b->bd_group));
1578 mb_check_buddy(e4b);
1579 mb_mark_used_double(e4b, start, len);
1580
1581 e4b->bd_info->bb_free -= len;
1582 if (e4b->bd_info->bb_first_free == start)
1583 e4b->bd_info->bb_first_free += len;
1584
1585 /* let's maintain fragments counter */
1586 if (start != 0)
1587 mlen = !mb_test_bit(start - 1, e4b->bd_bitmap);
1588 if (start + len < EXT4_SB(e4b->bd_sb)->s_mb_maxs[0])
1589 max = !mb_test_bit(start + len, e4b->bd_bitmap);
1590 if (mlen && max)
1591 e4b->bd_info->bb_fragments++;
1592 else if (!mlen && !max)
1593 e4b->bd_info->bb_fragments--;
1594
1595 /* let's maintain buddy itself */
1596 while (len) {
1597 ord = mb_find_order_for_block(e4b, start);
1598
1599 if (((start >> ord) << ord) == start && len >= (1 << ord)) {
1600 /* the whole chunk may be allocated at once! */
1601 mlen = 1 << ord;
1602 buddy = mb_find_buddy(e4b, ord, &max);
1603 BUG_ON((start >> ord) >= max);
1604 mb_set_bit(start >> ord, buddy);
1605 e4b->bd_info->bb_counters[ord]--;
1606 start += mlen;
1607 len -= mlen;
1608 BUG_ON(len < 0);
1609 continue;
1610 }
1611
1612 /* store for history */
1613 if (ret == 0)
1614 ret = len | (ord << 16);
1615
1616 /* we have to split large buddy */
1617 BUG_ON(ord <= 0);
1618 buddy = mb_find_buddy(e4b, ord, &max);
1619 mb_set_bit(start >> ord, buddy);
1620 e4b->bd_info->bb_counters[ord]--;
1621
1622 ord--;
1623 cur = (start >> ord) & ~1U;
1624 buddy = mb_find_buddy(e4b, ord, &max);
1625 mb_clear_bit(cur, buddy);
1626 mb_clear_bit(cur + 1, buddy);
1627 e4b->bd_info->bb_counters[ord]++;
1628 e4b->bd_info->bb_counters[ord]++;
1629 }
1630 mb_set_largest_free_order(e4b->bd_sb, e4b->bd_info);
1631
1632 ext4_set_bits(e4b->bd_bitmap, ex->fe_start, len0);
1633 mb_check_buddy(e4b);
1634
1635 return ret;
1636}
1637
1638/*
1639 * Must be called under group lock!
1640 */
1641static void ext4_mb_use_best_found(struct ext4_allocation_context *ac,
1642 struct ext4_buddy *e4b)
1643{
1644 struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
1645 int ret;
1646
1647 BUG_ON(ac->ac_b_ex.fe_group != e4b->bd_group);
1648 BUG_ON(ac->ac_status == AC_STATUS_FOUND);
1649
1650 ac->ac_b_ex.fe_len = min(ac->ac_b_ex.fe_len, ac->ac_g_ex.fe_len);
1651 ac->ac_b_ex.fe_logical = ac->ac_g_ex.fe_logical;
1652 ret = mb_mark_used(e4b, &ac->ac_b_ex);
1653
1654 /* preallocation can change ac_b_ex, thus we store actually
1655 * allocated blocks for history */
1656 ac->ac_f_ex = ac->ac_b_ex;
1657
1658 ac->ac_status = AC_STATUS_FOUND;
1659 ac->ac_tail = ret & 0xffff;
1660 ac->ac_buddy = ret >> 16;
1661
1662 /*
1663 * take the page reference. We want the page to be pinned
1664 * so that we don't get a ext4_mb_init_cache_call for this
1665 * group until we update the bitmap. That would mean we
1666 * double allocate blocks. The reference is dropped
1667 * in ext4_mb_release_context
1668 */
1669 ac->ac_bitmap_page = e4b->bd_bitmap_page;
1670 get_page(ac->ac_bitmap_page);
1671 ac->ac_buddy_page = e4b->bd_buddy_page;
1672 get_page(ac->ac_buddy_page);
1673 /* store last allocated for subsequent stream allocation */
1674 if (ac->ac_flags & EXT4_MB_STREAM_ALLOC) {
1675 spin_lock(&sbi->s_md_lock);
1676 sbi->s_mb_last_group = ac->ac_f_ex.fe_group;
1677 sbi->s_mb_last_start = ac->ac_f_ex.fe_start;
1678 spin_unlock(&sbi->s_md_lock);
1679 }
1680}
1681
1682/*
1683 * regular allocator, for general purposes allocation
1684 */
1685
1686static void ext4_mb_check_limits(struct ext4_allocation_context *ac,
1687 struct ext4_buddy *e4b,
1688 int finish_group)
1689{
1690 struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
1691 struct ext4_free_extent *bex = &ac->ac_b_ex;
1692 struct ext4_free_extent *gex = &ac->ac_g_ex;
1693 struct ext4_free_extent ex;
1694 int max;
1695
1696 if (ac->ac_status == AC_STATUS_FOUND)
1697 return;
1698 /*
1699 * We don't want to scan for a whole year
1700 */
1701 if (ac->ac_found > sbi->s_mb_max_to_scan &&
1702 !(ac->ac_flags & EXT4_MB_HINT_FIRST)) {
1703 ac->ac_status = AC_STATUS_BREAK;
1704 return;
1705 }
1706
1707 /*
1708 * Haven't found good chunk so far, let's continue
1709 */
1710 if (bex->fe_len < gex->fe_len)
1711 return;
1712
1713 if ((finish_group || ac->ac_found > sbi->s_mb_min_to_scan)
1714 && bex->fe_group == e4b->bd_group) {
1715 /* recheck chunk's availability - we don't know
1716 * when it was found (within this lock-unlock
1717 * period or not) */
1718 max = mb_find_extent(e4b, bex->fe_start, gex->fe_len, &ex);
1719 if (max >= gex->fe_len) {
1720 ext4_mb_use_best_found(ac, e4b);
1721 return;
1722 }
1723 }
1724}
1725
1726/*
1727 * The routine checks whether found extent is good enough. If it is,
1728 * then the extent gets marked used and flag is set to the context
1729 * to stop scanning. Otherwise, the extent is compared with the
1730 * previous found extent and if new one is better, then it's stored
1731 * in the context. Later, the best found extent will be used, if
1732 * mballoc can't find good enough extent.
1733 *
1734 * FIXME: real allocation policy is to be designed yet!
1735 */
1736static void ext4_mb_measure_extent(struct ext4_allocation_context *ac,
1737 struct ext4_free_extent *ex,
1738 struct ext4_buddy *e4b)
1739{
1740 struct ext4_free_extent *bex = &ac->ac_b_ex;
1741 struct ext4_free_extent *gex = &ac->ac_g_ex;
1742
1743 BUG_ON(ex->fe_len <= 0);
1744 BUG_ON(ex->fe_len > EXT4_CLUSTERS_PER_GROUP(ac->ac_sb));
1745 BUG_ON(ex->fe_start >= EXT4_CLUSTERS_PER_GROUP(ac->ac_sb));
1746 BUG_ON(ac->ac_status != AC_STATUS_CONTINUE);
1747
1748 ac->ac_found++;
1749
1750 /*
1751 * The special case - take what you catch first
1752 */
1753 if (unlikely(ac->ac_flags & EXT4_MB_HINT_FIRST)) {
1754 *bex = *ex;
1755 ext4_mb_use_best_found(ac, e4b);
1756 return;
1757 }
1758
1759 /*
1760 * Let's check whether the chuck is good enough
1761 */
1762 if (ex->fe_len == gex->fe_len) {
1763 *bex = *ex;
1764 ext4_mb_use_best_found(ac, e4b);
1765 return;
1766 }
1767
1768 /*
1769 * If this is first found extent, just store it in the context
1770 */
1771 if (bex->fe_len == 0) {
1772 *bex = *ex;
1773 return;
1774 }
1775
1776 /*
1777 * If new found extent is better, store it in the context
1778 */
1779 if (bex->fe_len < gex->fe_len) {
1780 /* if the request isn't satisfied, any found extent
1781 * larger than previous best one is better */
1782 if (ex->fe_len > bex->fe_len)
1783 *bex = *ex;
1784 } else if (ex->fe_len > gex->fe_len) {
1785 /* if the request is satisfied, then we try to find
1786 * an extent that still satisfy the request, but is
1787 * smaller than previous one */
1788 if (ex->fe_len < bex->fe_len)
1789 *bex = *ex;
1790 }
1791
1792 ext4_mb_check_limits(ac, e4b, 0);
1793}
1794
1795static noinline_for_stack
1796int ext4_mb_try_best_found(struct ext4_allocation_context *ac,
1797 struct ext4_buddy *e4b)
1798{
1799 struct ext4_free_extent ex = ac->ac_b_ex;
1800 ext4_group_t group = ex.fe_group;
1801 int max;
1802 int err;
1803
1804 BUG_ON(ex.fe_len <= 0);
1805 err = ext4_mb_load_buddy(ac->ac_sb, group, e4b);
1806 if (err)
1807 return err;
1808
1809 ext4_lock_group(ac->ac_sb, group);
1810 max = mb_find_extent(e4b, ex.fe_start, ex.fe_len, &ex);
1811
1812 if (max > 0) {
1813 ac->ac_b_ex = ex;
1814 ext4_mb_use_best_found(ac, e4b);
1815 }
1816
1817 ext4_unlock_group(ac->ac_sb, group);
1818 ext4_mb_unload_buddy(e4b);
1819
1820 return 0;
1821}
1822
1823static noinline_for_stack
1824int ext4_mb_find_by_goal(struct ext4_allocation_context *ac,
1825 struct ext4_buddy *e4b)
1826{
1827 ext4_group_t group = ac->ac_g_ex.fe_group;
1828 int max;
1829 int err;
1830 struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
1831 struct ext4_group_info *grp = ext4_get_group_info(ac->ac_sb, group);
1832 struct ext4_free_extent ex;
1833
1834 if (!(ac->ac_flags & EXT4_MB_HINT_TRY_GOAL))
1835 return 0;
1836 if (grp->bb_free == 0)
1837 return 0;
1838
1839 err = ext4_mb_load_buddy(ac->ac_sb, group, e4b);
1840 if (err)
1841 return err;
1842
1843 if (unlikely(EXT4_MB_GRP_BBITMAP_CORRUPT(e4b->bd_info))) {
1844 ext4_mb_unload_buddy(e4b);
1845 return 0;
1846 }
1847
1848 ext4_lock_group(ac->ac_sb, group);
1849 max = mb_find_extent(e4b, ac->ac_g_ex.fe_start,
1850 ac->ac_g_ex.fe_len, &ex);
1851 ex.fe_logical = 0xDEADFA11; /* debug value */
1852
1853 if (max >= ac->ac_g_ex.fe_len && ac->ac_g_ex.fe_len == sbi->s_stripe) {
1854 ext4_fsblk_t start;
1855
1856 start = ext4_group_first_block_no(ac->ac_sb, e4b->bd_group) +
1857 ex.fe_start;
1858 /* use do_div to get remainder (would be 64-bit modulo) */
1859 if (do_div(start, sbi->s_stripe) == 0) {
1860 ac->ac_found++;
1861 ac->ac_b_ex = ex;
1862 ext4_mb_use_best_found(ac, e4b);
1863 }
1864 } else if (max >= ac->ac_g_ex.fe_len) {
1865 BUG_ON(ex.fe_len <= 0);
1866 BUG_ON(ex.fe_group != ac->ac_g_ex.fe_group);
1867 BUG_ON(ex.fe_start != ac->ac_g_ex.fe_start);
1868 ac->ac_found++;
1869 ac->ac_b_ex = ex;
1870 ext4_mb_use_best_found(ac, e4b);
1871 } else if (max > 0 && (ac->ac_flags & EXT4_MB_HINT_MERGE)) {
1872 /* Sometimes, caller may want to merge even small
1873 * number of blocks to an existing extent */
1874 BUG_ON(ex.fe_len <= 0);
1875 BUG_ON(ex.fe_group != ac->ac_g_ex.fe_group);
1876 BUG_ON(ex.fe_start != ac->ac_g_ex.fe_start);
1877 ac->ac_found++;
1878 ac->ac_b_ex = ex;
1879 ext4_mb_use_best_found(ac, e4b);
1880 }
1881 ext4_unlock_group(ac->ac_sb, group);
1882 ext4_mb_unload_buddy(e4b);
1883
1884 return 0;
1885}
1886
1887/*
1888 * The routine scans buddy structures (not bitmap!) from given order
1889 * to max order and tries to find big enough chunk to satisfy the req
1890 */
1891static noinline_for_stack
1892void ext4_mb_simple_scan_group(struct ext4_allocation_context *ac,
1893 struct ext4_buddy *e4b)
1894{
1895 struct super_block *sb = ac->ac_sb;
1896 struct ext4_group_info *grp = e4b->bd_info;
1897 void *buddy;
1898 int i;
1899 int k;
1900 int max;
1901
1902 BUG_ON(ac->ac_2order <= 0);
1903 for (i = ac->ac_2order; i <= sb->s_blocksize_bits + 1; i++) {
1904 if (grp->bb_counters[i] == 0)
1905 continue;
1906
1907 buddy = mb_find_buddy(e4b, i, &max);
1908 BUG_ON(buddy == NULL);
1909
1910 k = mb_find_next_zero_bit(buddy, max, 0);
1911 BUG_ON(k >= max);
1912
1913 ac->ac_found++;
1914
1915 ac->ac_b_ex.fe_len = 1 << i;
1916 ac->ac_b_ex.fe_start = k << i;
1917 ac->ac_b_ex.fe_group = e4b->bd_group;
1918
1919 ext4_mb_use_best_found(ac, e4b);
1920
1921 BUG_ON(ac->ac_b_ex.fe_len != ac->ac_g_ex.fe_len);
1922
1923 if (EXT4_SB(sb)->s_mb_stats)
1924 atomic_inc(&EXT4_SB(sb)->s_bal_2orders);
1925
1926 break;
1927 }
1928}
1929
1930/*
1931 * The routine scans the group and measures all found extents.
1932 * In order to optimize scanning, caller must pass number of
1933 * free blocks in the group, so the routine can know upper limit.
1934 */
1935static noinline_for_stack
1936void ext4_mb_complex_scan_group(struct ext4_allocation_context *ac,
1937 struct ext4_buddy *e4b)
1938{
1939 struct super_block *sb = ac->ac_sb;
1940 void *bitmap = e4b->bd_bitmap;
1941 struct ext4_free_extent ex;
1942 int i;
1943 int free;
1944
1945 free = e4b->bd_info->bb_free;
1946 BUG_ON(free <= 0);
1947
1948 i = e4b->bd_info->bb_first_free;
1949
1950 while (free && ac->ac_status == AC_STATUS_CONTINUE) {
1951 i = mb_find_next_zero_bit(bitmap,
1952 EXT4_CLUSTERS_PER_GROUP(sb), i);
1953 if (i >= EXT4_CLUSTERS_PER_GROUP(sb)) {
1954 /*
1955 * IF we have corrupt bitmap, we won't find any
1956 * free blocks even though group info says we
1957 * we have free blocks
1958 */
1959 ext4_grp_locked_error(sb, e4b->bd_group, 0, 0,
1960 "%d free clusters as per "
1961 "group info. But bitmap says 0",
1962 free);
1963 break;
1964 }
1965
1966 mb_find_extent(e4b, i, ac->ac_g_ex.fe_len, &ex);
1967 BUG_ON(ex.fe_len <= 0);
1968 if (free < ex.fe_len) {
1969 ext4_grp_locked_error(sb, e4b->bd_group, 0, 0,
1970 "%d free clusters as per "
1971 "group info. But got %d blocks",
1972 free, ex.fe_len);
1973 /*
1974 * The number of free blocks differs. This mostly
1975 * indicate that the bitmap is corrupt. So exit
1976 * without claiming the space.
1977 */
1978 break;
1979 }
1980 ex.fe_logical = 0xDEADC0DE; /* debug value */
1981 ext4_mb_measure_extent(ac, &ex, e4b);
1982
1983 i += ex.fe_len;
1984 free -= ex.fe_len;
1985 }
1986
1987 ext4_mb_check_limits(ac, e4b, 1);
1988}
1989
1990/*
1991 * This is a special case for storages like raid5
1992 * we try to find stripe-aligned chunks for stripe-size-multiple requests
1993 */
1994static noinline_for_stack
1995void ext4_mb_scan_aligned(struct ext4_allocation_context *ac,
1996 struct ext4_buddy *e4b)
1997{
1998 struct super_block *sb = ac->ac_sb;
1999 struct ext4_sb_info *sbi = EXT4_SB(sb);
2000 void *bitmap = e4b->bd_bitmap;
2001 struct ext4_free_extent ex;
2002 ext4_fsblk_t first_group_block;
2003 ext4_fsblk_t a;
2004 ext4_grpblk_t i;
2005 int max;
2006
2007 BUG_ON(sbi->s_stripe == 0);
2008
2009 /* find first stripe-aligned block in group */
2010 first_group_block = ext4_group_first_block_no(sb, e4b->bd_group);
2011
2012 a = first_group_block + sbi->s_stripe - 1;
2013 do_div(a, sbi->s_stripe);
2014 i = (a * sbi->s_stripe) - first_group_block;
2015
2016 while (i < EXT4_CLUSTERS_PER_GROUP(sb)) {
2017 if (!mb_test_bit(i, bitmap)) {
2018 max = mb_find_extent(e4b, i, sbi->s_stripe, &ex);
2019 if (max >= sbi->s_stripe) {
2020 ac->ac_found++;
2021 ex.fe_logical = 0xDEADF00D; /* debug value */
2022 ac->ac_b_ex = ex;
2023 ext4_mb_use_best_found(ac, e4b);
2024 break;
2025 }
2026 }
2027 i += sbi->s_stripe;
2028 }
2029}
2030
2031/*
2032 * This is now called BEFORE we load the buddy bitmap.
2033 * Returns either 1 or 0 indicating that the group is either suitable
2034 * for the allocation or not. In addition it can also return negative
2035 * error code when something goes wrong.
2036 */
2037static int ext4_mb_good_group(struct ext4_allocation_context *ac,
2038 ext4_group_t group, int cr)
2039{
2040 unsigned free, fragments;
2041 int flex_size = ext4_flex_bg_size(EXT4_SB(ac->ac_sb));
2042 struct ext4_group_info *grp = ext4_get_group_info(ac->ac_sb, group);
2043
2044 BUG_ON(cr < 0 || cr >= 4);
2045
2046 free = grp->bb_free;
2047 if (free == 0)
2048 return 0;
2049 if (cr <= 2 && free < ac->ac_g_ex.fe_len)
2050 return 0;
2051
2052 if (unlikely(EXT4_MB_GRP_BBITMAP_CORRUPT(grp)))
2053 return 0;
2054
2055 /* We only do this if the grp has never been initialized */
2056 if (unlikely(EXT4_MB_GRP_NEED_INIT(grp))) {
2057 int ret = ext4_mb_init_group(ac->ac_sb, group, GFP_NOFS);
2058 if (ret)
2059 return ret;
2060 }
2061
2062 fragments = grp->bb_fragments;
2063 if (fragments == 0)
2064 return 0;
2065
2066 switch (cr) {
2067 case 0:
2068 BUG_ON(ac->ac_2order == 0);
2069
2070 /* Avoid using the first bg of a flexgroup for data files */
2071 if ((ac->ac_flags & EXT4_MB_HINT_DATA) &&
2072 (flex_size >= EXT4_FLEX_SIZE_DIR_ALLOC_SCHEME) &&
2073 ((group % flex_size) == 0))
2074 return 0;
2075
2076 if ((ac->ac_2order > ac->ac_sb->s_blocksize_bits+1) ||
2077 (free / fragments) >= ac->ac_g_ex.fe_len)
2078 return 1;
2079
2080 if (grp->bb_largest_free_order < ac->ac_2order)
2081 return 0;
2082
2083 return 1;
2084 case 1:
2085 if ((free / fragments) >= ac->ac_g_ex.fe_len)
2086 return 1;
2087 break;
2088 case 2:
2089 if (free >= ac->ac_g_ex.fe_len)
2090 return 1;
2091 break;
2092 case 3:
2093 return 1;
2094 default:
2095 BUG();
2096 }
2097
2098 return 0;
2099}
2100
2101static noinline_for_stack int
2102ext4_mb_regular_allocator(struct ext4_allocation_context *ac)
2103{
2104 ext4_group_t ngroups, group, i;
2105 int cr;
2106 int err = 0, first_err = 0;
2107 struct ext4_sb_info *sbi;
2108 struct super_block *sb;
2109 struct ext4_buddy e4b;
2110
2111 sb = ac->ac_sb;
2112 sbi = EXT4_SB(sb);
2113 ngroups = ext4_get_groups_count(sb);
2114 /* non-extent files are limited to low blocks/groups */
2115 if (!(ext4_test_inode_flag(ac->ac_inode, EXT4_INODE_EXTENTS)))
2116 ngroups = sbi->s_blockfile_groups;
2117
2118 BUG_ON(ac->ac_status == AC_STATUS_FOUND);
2119
2120 /* first, try the goal */
2121 err = ext4_mb_find_by_goal(ac, &e4b);
2122 if (err || ac->ac_status == AC_STATUS_FOUND)
2123 goto out;
2124
2125 if (unlikely(ac->ac_flags & EXT4_MB_HINT_GOAL_ONLY))
2126 goto out;
2127
2128 /*
2129 * ac->ac2_order is set only if the fe_len is a power of 2
2130 * if ac2_order is set we also set criteria to 0 so that we
2131 * try exact allocation using buddy.
2132 */
2133 i = fls(ac->ac_g_ex.fe_len);
2134 ac->ac_2order = 0;
2135 /*
2136 * We search using buddy data only if the order of the request
2137 * is greater than equal to the sbi_s_mb_order2_reqs
2138 * You can tune it via /sys/fs/ext4/<partition>/mb_order2_req
2139 */
2140 if (i >= sbi->s_mb_order2_reqs) {
2141 /*
2142 * This should tell if fe_len is exactly power of 2
2143 */
2144 if ((ac->ac_g_ex.fe_len & (~(1 << (i - 1)))) == 0)
2145 ac->ac_2order = i - 1;
2146 }
2147
2148 /* if stream allocation is enabled, use global goal */
2149 if (ac->ac_flags & EXT4_MB_STREAM_ALLOC) {
2150 /* TBD: may be hot point */
2151 spin_lock(&sbi->s_md_lock);
2152 ac->ac_g_ex.fe_group = sbi->s_mb_last_group;
2153 ac->ac_g_ex.fe_start = sbi->s_mb_last_start;
2154 spin_unlock(&sbi->s_md_lock);
2155 }
2156
2157 /* Let's just scan groups to find more-less suitable blocks */
2158 cr = ac->ac_2order ? 0 : 1;
2159 /*
2160 * cr == 0 try to get exact allocation,
2161 * cr == 3 try to get anything
2162 */
2163repeat:
2164 for (; cr < 4 && ac->ac_status == AC_STATUS_CONTINUE; cr++) {
2165 ac->ac_criteria = cr;
2166 /*
2167 * searching for the right group start
2168 * from the goal value specified
2169 */
2170 group = ac->ac_g_ex.fe_group;
2171
2172 for (i = 0; i < ngroups; group++, i++) {
2173 int ret = 0;
2174 cond_resched();
2175 /*
2176 * Artificially restricted ngroups for non-extent
2177 * files makes group > ngroups possible on first loop.
2178 */
2179 if (group >= ngroups)
2180 group = 0;
2181
2182 /* This now checks without needing the buddy page */
2183 ret = ext4_mb_good_group(ac, group, cr);
2184 if (ret <= 0) {
2185 if (!first_err)
2186 first_err = ret;
2187 continue;
2188 }
2189
2190 err = ext4_mb_load_buddy(sb, group, &e4b);
2191 if (err)
2192 goto out;
2193
2194 ext4_lock_group(sb, group);
2195
2196 /*
2197 * We need to check again after locking the
2198 * block group
2199 */
2200 ret = ext4_mb_good_group(ac, group, cr);
2201 if (ret <= 0) {
2202 ext4_unlock_group(sb, group);
2203 ext4_mb_unload_buddy(&e4b);
2204 if (!first_err)
2205 first_err = ret;
2206 continue;
2207 }
2208
2209 ac->ac_groups_scanned++;
2210 if (cr == 0 && ac->ac_2order < sb->s_blocksize_bits+2)
2211 ext4_mb_simple_scan_group(ac, &e4b);
2212 else if (cr == 1 && sbi->s_stripe &&
2213 !(ac->ac_g_ex.fe_len % sbi->s_stripe))
2214 ext4_mb_scan_aligned(ac, &e4b);
2215 else
2216 ext4_mb_complex_scan_group(ac, &e4b);
2217
2218 ext4_unlock_group(sb, group);
2219 ext4_mb_unload_buddy(&e4b);
2220
2221 if (ac->ac_status != AC_STATUS_CONTINUE)
2222 break;
2223 }
2224 }
2225
2226 if (ac->ac_b_ex.fe_len > 0 && ac->ac_status != AC_STATUS_FOUND &&
2227 !(ac->ac_flags & EXT4_MB_HINT_FIRST)) {
2228 /*
2229 * We've been searching too long. Let's try to allocate
2230 * the best chunk we've found so far
2231 */
2232
2233 ext4_mb_try_best_found(ac, &e4b);
2234 if (ac->ac_status != AC_STATUS_FOUND) {
2235 /*
2236 * Someone more lucky has already allocated it.
2237 * The only thing we can do is just take first
2238 * found block(s)
2239 printk(KERN_DEBUG "EXT4-fs: someone won our chunk\n");
2240 */
2241 ac->ac_b_ex.fe_group = 0;
2242 ac->ac_b_ex.fe_start = 0;
2243 ac->ac_b_ex.fe_len = 0;
2244 ac->ac_status = AC_STATUS_CONTINUE;
2245 ac->ac_flags |= EXT4_MB_HINT_FIRST;
2246 cr = 3;
2247 atomic_inc(&sbi->s_mb_lost_chunks);
2248 goto repeat;
2249 }
2250 }
2251out:
2252 if (!err && ac->ac_status != AC_STATUS_FOUND && first_err)
2253 err = first_err;
2254 return err;
2255}
2256
2257static void *ext4_mb_seq_groups_start(struct seq_file *seq, loff_t *pos)
2258{
2259 struct super_block *sb = seq->private;
2260 ext4_group_t group;
2261
2262 if (*pos < 0 || *pos >= ext4_get_groups_count(sb))
2263 return NULL;
2264 group = *pos + 1;
2265 return (void *) ((unsigned long) group);
2266}
2267
2268static void *ext4_mb_seq_groups_next(struct seq_file *seq, void *v, loff_t *pos)
2269{
2270 struct super_block *sb = seq->private;
2271 ext4_group_t group;
2272
2273 ++*pos;
2274 if (*pos < 0 || *pos >= ext4_get_groups_count(sb))
2275 return NULL;
2276 group = *pos + 1;
2277 return (void *) ((unsigned long) group);
2278}
2279
2280static int ext4_mb_seq_groups_show(struct seq_file *seq, void *v)
2281{
2282 struct super_block *sb = seq->private;
2283 ext4_group_t group = (ext4_group_t) ((unsigned long) v);
2284 int i;
2285 int err, buddy_loaded = 0;
2286 struct ext4_buddy e4b;
2287 struct ext4_group_info *grinfo;
2288 struct sg {
2289 struct ext4_group_info info;
2290 ext4_grpblk_t counters[EXT4_MAX_BLOCK_LOG_SIZE + 2];
2291 } sg;
2292
2293 group--;
2294 if (group == 0)
2295 seq_puts(seq, "#group: free frags first ["
2296 " 2^0 2^1 2^2 2^3 2^4 2^5 2^6 "
2297 " 2^7 2^8 2^9 2^10 2^11 2^12 2^13 ]\n");
2298
2299 i = (sb->s_blocksize_bits + 2) * sizeof(sg.info.bb_counters[0]) +
2300 sizeof(struct ext4_group_info);
2301 grinfo = ext4_get_group_info(sb, group);
2302 /* Load the group info in memory only if not already loaded. */
2303 if (unlikely(EXT4_MB_GRP_NEED_INIT(grinfo))) {
2304 err = ext4_mb_load_buddy(sb, group, &e4b);
2305 if (err) {
2306 seq_printf(seq, "#%-5u: I/O error\n", group);
2307 return 0;
2308 }
2309 buddy_loaded = 1;
2310 }
2311
2312 memcpy(&sg, ext4_get_group_info(sb, group), i);
2313
2314 if (buddy_loaded)
2315 ext4_mb_unload_buddy(&e4b);
2316
2317 seq_printf(seq, "#%-5u: %-5u %-5u %-5u [", group, sg.info.bb_free,
2318 sg.info.bb_fragments, sg.info.bb_first_free);
2319 for (i = 0; i <= 13; i++)
2320 seq_printf(seq, " %-5u", i <= sb->s_blocksize_bits + 1 ?
2321 sg.info.bb_counters[i] : 0);
2322 seq_printf(seq, " ]\n");
2323
2324 return 0;
2325}
2326
2327static void ext4_mb_seq_groups_stop(struct seq_file *seq, void *v)
2328{
2329}
2330
2331static const struct seq_operations ext4_mb_seq_groups_ops = {
2332 .start = ext4_mb_seq_groups_start,
2333 .next = ext4_mb_seq_groups_next,
2334 .stop = ext4_mb_seq_groups_stop,
2335 .show = ext4_mb_seq_groups_show,
2336};
2337
2338static int ext4_mb_seq_groups_open(struct inode *inode, struct file *file)
2339{
2340 struct super_block *sb = PDE_DATA(inode);
2341 int rc;
2342
2343 rc = seq_open(file, &ext4_mb_seq_groups_ops);
2344 if (rc == 0) {
2345 struct seq_file *m = file->private_data;
2346 m->private = sb;
2347 }
2348 return rc;
2349
2350}
2351
2352const struct file_operations ext4_seq_mb_groups_fops = {
2353 .open = ext4_mb_seq_groups_open,
2354 .read = seq_read,
2355 .llseek = seq_lseek,
2356 .release = seq_release,
2357};
2358
2359static struct kmem_cache *get_groupinfo_cache(int blocksize_bits)
2360{
2361 int cache_index = blocksize_bits - EXT4_MIN_BLOCK_LOG_SIZE;
2362 struct kmem_cache *cachep = ext4_groupinfo_caches[cache_index];
2363
2364 BUG_ON(!cachep);
2365 return cachep;
2366}
2367
2368/*
2369 * Allocate the top-level s_group_info array for the specified number
2370 * of groups
2371 */
2372int ext4_mb_alloc_groupinfo(struct super_block *sb, ext4_group_t ngroups)
2373{
2374 struct ext4_sb_info *sbi = EXT4_SB(sb);
2375 unsigned size;
2376 struct ext4_group_info ***new_groupinfo;
2377
2378 size = (ngroups + EXT4_DESC_PER_BLOCK(sb) - 1) >>
2379 EXT4_DESC_PER_BLOCK_BITS(sb);
2380 if (size <= sbi->s_group_info_size)
2381 return 0;
2382
2383 size = roundup_pow_of_two(sizeof(*sbi->s_group_info) * size);
2384 new_groupinfo = ext4_kvzalloc(size, GFP_KERNEL);
2385 if (!new_groupinfo) {
2386 ext4_msg(sb, KERN_ERR, "can't allocate buddy meta group");
2387 return -ENOMEM;
2388 }
2389 if (sbi->s_group_info) {
2390 memcpy(new_groupinfo, sbi->s_group_info,
2391 sbi->s_group_info_size * sizeof(*sbi->s_group_info));
2392 kvfree(sbi->s_group_info);
2393 }
2394 sbi->s_group_info = new_groupinfo;
2395 sbi->s_group_info_size = size / sizeof(*sbi->s_group_info);
2396 ext4_debug("allocated s_groupinfo array for %d meta_bg's\n",
2397 sbi->s_group_info_size);
2398 return 0;
2399}
2400
2401/* Create and initialize ext4_group_info data for the given group. */
2402int ext4_mb_add_groupinfo(struct super_block *sb, ext4_group_t group,
2403 struct ext4_group_desc *desc)
2404{
2405 int i;
2406 int metalen = 0;
2407 struct ext4_sb_info *sbi = EXT4_SB(sb);
2408 struct ext4_group_info **meta_group_info;
2409 struct kmem_cache *cachep = get_groupinfo_cache(sb->s_blocksize_bits);
2410
2411 /*
2412 * First check if this group is the first of a reserved block.
2413 * If it's true, we have to allocate a new table of pointers
2414 * to ext4_group_info structures
2415 */
2416 if (group % EXT4_DESC_PER_BLOCK(sb) == 0) {
2417 metalen = sizeof(*meta_group_info) <<
2418 EXT4_DESC_PER_BLOCK_BITS(sb);
2419 meta_group_info = kmalloc(metalen, GFP_NOFS);
2420 if (meta_group_info == NULL) {
2421 ext4_msg(sb, KERN_ERR, "can't allocate mem "
2422 "for a buddy group");
2423 goto exit_meta_group_info;
2424 }
2425 sbi->s_group_info[group >> EXT4_DESC_PER_BLOCK_BITS(sb)] =
2426 meta_group_info;
2427 }
2428
2429 meta_group_info =
2430 sbi->s_group_info[group >> EXT4_DESC_PER_BLOCK_BITS(sb)];
2431 i = group & (EXT4_DESC_PER_BLOCK(sb) - 1);
2432
2433 meta_group_info[i] = kmem_cache_zalloc(cachep, GFP_NOFS);
2434 if (meta_group_info[i] == NULL) {
2435 ext4_msg(sb, KERN_ERR, "can't allocate buddy mem");
2436 goto exit_group_info;
2437 }
2438 set_bit(EXT4_GROUP_INFO_NEED_INIT_BIT,
2439 &(meta_group_info[i]->bb_state));
2440
2441 /*
2442 * initialize bb_free to be able to skip
2443 * empty groups without initialization
2444 */
2445 if (desc->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) {
2446 meta_group_info[i]->bb_free =
2447 ext4_free_clusters_after_init(sb, group, desc);
2448 } else {
2449 meta_group_info[i]->bb_free =
2450 ext4_free_group_clusters(sb, desc);
2451 }
2452
2453 INIT_LIST_HEAD(&meta_group_info[i]->bb_prealloc_list);
2454 init_rwsem(&meta_group_info[i]->alloc_sem);
2455 meta_group_info[i]->bb_free_root = RB_ROOT;
2456 meta_group_info[i]->bb_largest_free_order = -1; /* uninit */
2457
2458#ifdef DOUBLE_CHECK
2459 {
2460 struct buffer_head *bh;
2461 meta_group_info[i]->bb_bitmap =
2462 kmalloc(sb->s_blocksize, GFP_NOFS);
2463 BUG_ON(meta_group_info[i]->bb_bitmap == NULL);
2464 bh = ext4_read_block_bitmap(sb, group);
2465 BUG_ON(IS_ERR_OR_NULL(bh));
2466 memcpy(meta_group_info[i]->bb_bitmap, bh->b_data,
2467 sb->s_blocksize);
2468 put_bh(bh);
2469 }
2470#endif
2471
2472 return 0;
2473
2474exit_group_info:
2475 /* If a meta_group_info table has been allocated, release it now */
2476 if (group % EXT4_DESC_PER_BLOCK(sb) == 0) {
2477 kfree(sbi->s_group_info[group >> EXT4_DESC_PER_BLOCK_BITS(sb)]);
2478 sbi->s_group_info[group >> EXT4_DESC_PER_BLOCK_BITS(sb)] = NULL;
2479 }
2480exit_meta_group_info:
2481 return -ENOMEM;
2482} /* ext4_mb_add_groupinfo */
2483
2484static int ext4_mb_init_backend(struct super_block *sb)
2485{
2486 ext4_group_t ngroups = ext4_get_groups_count(sb);
2487 ext4_group_t i;
2488 struct ext4_sb_info *sbi = EXT4_SB(sb);
2489 int err;
2490 struct ext4_group_desc *desc;
2491 struct kmem_cache *cachep;
2492
2493 err = ext4_mb_alloc_groupinfo(sb, ngroups);
2494 if (err)
2495 return err;
2496
2497 sbi->s_buddy_cache = new_inode(sb);
2498 if (sbi->s_buddy_cache == NULL) {
2499 ext4_msg(sb, KERN_ERR, "can't get new inode");
2500 goto err_freesgi;
2501 }
2502 /* To avoid potentially colliding with an valid on-disk inode number,
2503 * use EXT4_BAD_INO for the buddy cache inode number. This inode is
2504 * not in the inode hash, so it should never be found by iget(), but
2505 * this will avoid confusion if it ever shows up during debugging. */
2506 sbi->s_buddy_cache->i_ino = EXT4_BAD_INO;
2507 EXT4_I(sbi->s_buddy_cache)->i_disksize = 0;
2508 for (i = 0; i < ngroups; i++) {
2509 desc = ext4_get_group_desc(sb, i, NULL);
2510 if (desc == NULL) {
2511 ext4_msg(sb, KERN_ERR, "can't read descriptor %u", i);
2512 goto err_freebuddy;
2513 }
2514 if (ext4_mb_add_groupinfo(sb, i, desc) != 0)
2515 goto err_freebuddy;
2516 }
2517
2518 return 0;
2519
2520err_freebuddy:
2521 cachep = get_groupinfo_cache(sb->s_blocksize_bits);
2522 while (i-- > 0)
2523 kmem_cache_free(cachep, ext4_get_group_info(sb, i));
2524 i = sbi->s_group_info_size;
2525 while (i-- > 0)
2526 kfree(sbi->s_group_info[i]);
2527 iput(sbi->s_buddy_cache);
2528err_freesgi:
2529 kvfree(sbi->s_group_info);
2530 return -ENOMEM;
2531}
2532
2533static void ext4_groupinfo_destroy_slabs(void)
2534{
2535 int i;
2536
2537 for (i = 0; i < NR_GRPINFO_CACHES; i++) {
2538 if (ext4_groupinfo_caches[i])
2539 kmem_cache_destroy(ext4_groupinfo_caches[i]);
2540 ext4_groupinfo_caches[i] = NULL;
2541 }
2542}
2543
2544static int ext4_groupinfo_create_slab(size_t size)
2545{
2546 static DEFINE_MUTEX(ext4_grpinfo_slab_create_mutex);
2547 int slab_size;
2548 int blocksize_bits = order_base_2(size);
2549 int cache_index = blocksize_bits - EXT4_MIN_BLOCK_LOG_SIZE;
2550 struct kmem_cache *cachep;
2551
2552 if (cache_index >= NR_GRPINFO_CACHES)
2553 return -EINVAL;
2554
2555 if (unlikely(cache_index < 0))
2556 cache_index = 0;
2557
2558 mutex_lock(&ext4_grpinfo_slab_create_mutex);
2559 if (ext4_groupinfo_caches[cache_index]) {
2560 mutex_unlock(&ext4_grpinfo_slab_create_mutex);
2561 return 0; /* Already created */
2562 }
2563
2564 slab_size = offsetof(struct ext4_group_info,
2565 bb_counters[blocksize_bits + 2]);
2566
2567 cachep = kmem_cache_create(ext4_groupinfo_slab_names[cache_index],
2568 slab_size, 0, SLAB_RECLAIM_ACCOUNT,
2569 NULL);
2570
2571 ext4_groupinfo_caches[cache_index] = cachep;
2572
2573 mutex_unlock(&ext4_grpinfo_slab_create_mutex);
2574 if (!cachep) {
2575 printk(KERN_EMERG
2576 "EXT4-fs: no memory for groupinfo slab cache\n");
2577 return -ENOMEM;
2578 }
2579
2580 return 0;
2581}
2582
2583int ext4_mb_init(struct super_block *sb)
2584{
2585 struct ext4_sb_info *sbi = EXT4_SB(sb);
2586 unsigned i, j;
2587 unsigned offset, offset_incr;
2588 unsigned max;
2589 int ret;
2590
2591 i = (sb->s_blocksize_bits + 2) * sizeof(*sbi->s_mb_offsets);
2592
2593 sbi->s_mb_offsets = kmalloc(i, GFP_KERNEL);
2594 if (sbi->s_mb_offsets == NULL) {
2595 ret = -ENOMEM;
2596 goto out;
2597 }
2598
2599 i = (sb->s_blocksize_bits + 2) * sizeof(*sbi->s_mb_maxs);
2600 sbi->s_mb_maxs = kmalloc(i, GFP_KERNEL);
2601 if (sbi->s_mb_maxs == NULL) {
2602 ret = -ENOMEM;
2603 goto out;
2604 }
2605
2606 ret = ext4_groupinfo_create_slab(sb->s_blocksize);
2607 if (ret < 0)
2608 goto out;
2609
2610 /* order 0 is regular bitmap */
2611 sbi->s_mb_maxs[0] = sb->s_blocksize << 3;
2612 sbi->s_mb_offsets[0] = 0;
2613
2614 i = 1;
2615 offset = 0;
2616 offset_incr = 1 << (sb->s_blocksize_bits - 1);
2617 max = sb->s_blocksize << 2;
2618 do {
2619 sbi->s_mb_offsets[i] = offset;
2620 sbi->s_mb_maxs[i] = max;
2621 offset += offset_incr;
2622 offset_incr = offset_incr >> 1;
2623 max = max >> 1;
2624 i++;
2625 } while (i <= sb->s_blocksize_bits + 1);
2626
2627 spin_lock_init(&sbi->s_md_lock);
2628 spin_lock_init(&sbi->s_bal_lock);
2629 sbi->s_mb_free_pending = 0;
2630
2631 sbi->s_mb_max_to_scan = MB_DEFAULT_MAX_TO_SCAN;
2632 sbi->s_mb_min_to_scan = MB_DEFAULT_MIN_TO_SCAN;
2633 sbi->s_mb_stats = MB_DEFAULT_STATS;
2634 sbi->s_mb_stream_request = MB_DEFAULT_STREAM_THRESHOLD;
2635 sbi->s_mb_order2_reqs = MB_DEFAULT_ORDER2_REQS;
2636 /*
2637 * The default group preallocation is 512, which for 4k block
2638 * sizes translates to 2 megabytes. However for bigalloc file
2639 * systems, this is probably too big (i.e, if the cluster size
2640 * is 1 megabyte, then group preallocation size becomes half a
2641 * gigabyte!). As a default, we will keep a two megabyte
2642 * group pralloc size for cluster sizes up to 64k, and after
2643 * that, we will force a minimum group preallocation size of
2644 * 32 clusters. This translates to 8 megs when the cluster
2645 * size is 256k, and 32 megs when the cluster size is 1 meg,
2646 * which seems reasonable as a default.
2647 */
2648 sbi->s_mb_group_prealloc = max(MB_DEFAULT_GROUP_PREALLOC >>
2649 sbi->s_cluster_bits, 32);
2650 /*
2651 * If there is a s_stripe > 1, then we set the s_mb_group_prealloc
2652 * to the lowest multiple of s_stripe which is bigger than
2653 * the s_mb_group_prealloc as determined above. We want
2654 * the preallocation size to be an exact multiple of the
2655 * RAID stripe size so that preallocations don't fragment
2656 * the stripes.
2657 */
2658 if (sbi->s_stripe > 1) {
2659 sbi->s_mb_group_prealloc = roundup(
2660 sbi->s_mb_group_prealloc, sbi->s_stripe);
2661 }
2662
2663 sbi->s_locality_groups = alloc_percpu(struct ext4_locality_group);
2664 if (sbi->s_locality_groups == NULL) {
2665 ret = -ENOMEM;
2666 goto out;
2667 }
2668 for_each_possible_cpu(i) {
2669 struct ext4_locality_group *lg;
2670 lg = per_cpu_ptr(sbi->s_locality_groups, i);
2671 mutex_init(&lg->lg_mutex);
2672 for (j = 0; j < PREALLOC_TB_SIZE; j++)
2673 INIT_LIST_HEAD(&lg->lg_prealloc_list[j]);
2674 spin_lock_init(&lg->lg_prealloc_lock);
2675 }
2676
2677 /* init file for buddy data */
2678 ret = ext4_mb_init_backend(sb);
2679 if (ret != 0)
2680 goto out_free_locality_groups;
2681
2682 return 0;
2683
2684out_free_locality_groups:
2685 free_percpu(sbi->s_locality_groups);
2686 sbi->s_locality_groups = NULL;
2687out:
2688 kfree(sbi->s_mb_offsets);
2689 sbi->s_mb_offsets = NULL;
2690 kfree(sbi->s_mb_maxs);
2691 sbi->s_mb_maxs = NULL;
2692 return ret;
2693}
2694
2695/* need to called with the ext4 group lock held */
2696static void ext4_mb_cleanup_pa(struct ext4_group_info *grp)
2697{
2698 struct ext4_prealloc_space *pa;
2699 struct list_head *cur, *tmp;
2700 int count = 0;
2701
2702 list_for_each_safe(cur, tmp, &grp->bb_prealloc_list) {
2703 pa = list_entry(cur, struct ext4_prealloc_space, pa_group_list);
2704 list_del(&pa->pa_group_list);
2705 count++;
2706 kmem_cache_free(ext4_pspace_cachep, pa);
2707 }
2708 if (count)
2709 mb_debug(1, "mballoc: %u PAs left\n", count);
2710
2711}
2712
2713int ext4_mb_release(struct super_block *sb)
2714{
2715 ext4_group_t ngroups = ext4_get_groups_count(sb);
2716 ext4_group_t i;
2717 int num_meta_group_infos;
2718 struct ext4_group_info *grinfo;
2719 struct ext4_sb_info *sbi = EXT4_SB(sb);
2720 struct kmem_cache *cachep = get_groupinfo_cache(sb->s_blocksize_bits);
2721
2722 if (sbi->s_group_info) {
2723 for (i = 0; i < ngroups; i++) {
2724 grinfo = ext4_get_group_info(sb, i);
2725#ifdef DOUBLE_CHECK
2726 kfree(grinfo->bb_bitmap);
2727#endif
2728 ext4_lock_group(sb, i);
2729 ext4_mb_cleanup_pa(grinfo);
2730 ext4_unlock_group(sb, i);
2731 kmem_cache_free(cachep, grinfo);
2732 }
2733 num_meta_group_infos = (ngroups +
2734 EXT4_DESC_PER_BLOCK(sb) - 1) >>
2735 EXT4_DESC_PER_BLOCK_BITS(sb);
2736 for (i = 0; i < num_meta_group_infos; i++)
2737 kfree(sbi->s_group_info[i]);
2738 kvfree(sbi->s_group_info);
2739 }
2740 kfree(sbi->s_mb_offsets);
2741 kfree(sbi->s_mb_maxs);
2742 iput(sbi->s_buddy_cache);
2743 if (sbi->s_mb_stats) {
2744 ext4_msg(sb, KERN_INFO,
2745 "mballoc: %u blocks %u reqs (%u success)",
2746 atomic_read(&sbi->s_bal_allocated),
2747 atomic_read(&sbi->s_bal_reqs),
2748 atomic_read(&sbi->s_bal_success));
2749 ext4_msg(sb, KERN_INFO,
2750 "mballoc: %u extents scanned, %u goal hits, "
2751 "%u 2^N hits, %u breaks, %u lost",
2752 atomic_read(&sbi->s_bal_ex_scanned),
2753 atomic_read(&sbi->s_bal_goals),
2754 atomic_read(&sbi->s_bal_2orders),
2755 atomic_read(&sbi->s_bal_breaks),
2756 atomic_read(&sbi->s_mb_lost_chunks));
2757 ext4_msg(sb, KERN_INFO,
2758 "mballoc: %lu generated and it took %Lu",
2759 sbi->s_mb_buddies_generated,
2760 sbi->s_mb_generation_time);
2761 ext4_msg(sb, KERN_INFO,
2762 "mballoc: %u preallocated, %u discarded",
2763 atomic_read(&sbi->s_mb_preallocated),
2764 atomic_read(&sbi->s_mb_discarded));
2765 }
2766
2767 free_percpu(sbi->s_locality_groups);
2768
2769 return 0;
2770}
2771
2772static inline int ext4_issue_discard(struct super_block *sb,
2773 ext4_group_t block_group, ext4_grpblk_t cluster, int count)
2774{
2775 ext4_fsblk_t discard_block;
2776
2777 discard_block = (EXT4_C2B(EXT4_SB(sb), cluster) +
2778 ext4_group_first_block_no(sb, block_group));
2779 count = EXT4_C2B(EXT4_SB(sb), count);
2780 trace_ext4_discard_blocks(sb,
2781 (unsigned long long) discard_block, count);
2782 return sb_issue_discard(sb, discard_block, count, GFP_NOFS, 0);
2783}
2784
2785/*
2786 * This function is called by the jbd2 layer once the commit has finished,
2787 * so we know we can free the blocks that were released with that commit.
2788 */
2789static void ext4_free_data_callback(struct super_block *sb,
2790 struct ext4_journal_cb_entry *jce,
2791 int rc)
2792{
2793 struct ext4_free_data *entry = (struct ext4_free_data *)jce;
2794 struct ext4_buddy e4b;
2795 struct ext4_group_info *db;
2796 int err, count = 0, count2 = 0;
2797
2798 mb_debug(1, "gonna free %u blocks in group %u (0x%p):",
2799 entry->efd_count, entry->efd_group, entry);
2800
2801 if (test_opt(sb, DISCARD)) {
2802 err = ext4_issue_discard(sb, entry->efd_group,
2803 entry->efd_start_cluster,
2804 entry->efd_count);
2805 if (err && err != -EOPNOTSUPP)
2806 ext4_msg(sb, KERN_WARNING, "discard request in"
2807 " group:%d block:%d count:%d failed"
2808 " with %d", entry->efd_group,
2809 entry->efd_start_cluster,
2810 entry->efd_count, err);
2811 }
2812
2813 err = ext4_mb_load_buddy(sb, entry->efd_group, &e4b);
2814 /* we expect to find existing buddy because it's pinned */
2815 BUG_ON(err != 0);
2816
2817 spin_lock(&EXT4_SB(sb)->s_md_lock);
2818 EXT4_SB(sb)->s_mb_free_pending -= entry->efd_count;
2819 spin_unlock(&EXT4_SB(sb)->s_md_lock);
2820
2821 db = e4b.bd_info;
2822 /* there are blocks to put in buddy to make them really free */
2823 count += entry->efd_count;
2824 count2++;
2825 ext4_lock_group(sb, entry->efd_group);
2826 /* Take it out of per group rb tree */
2827 rb_erase(&entry->efd_node, &(db->bb_free_root));
2828 mb_free_blocks(NULL, &e4b, entry->efd_start_cluster, entry->efd_count);
2829
2830 /*
2831 * Clear the trimmed flag for the group so that the next
2832 * ext4_trim_fs can trim it.
2833 * If the volume is mounted with -o discard, online discard
2834 * is supported and the free blocks will be trimmed online.
2835 */
2836 if (!test_opt(sb, DISCARD))
2837 EXT4_MB_GRP_CLEAR_TRIMMED(db);
2838
2839 if (!db->bb_free_root.rb_node) {
2840 /* No more items in the per group rb tree
2841 * balance refcounts from ext4_mb_free_metadata()
2842 */
2843 put_page(e4b.bd_buddy_page);
2844 put_page(e4b.bd_bitmap_page);
2845 }
2846 ext4_unlock_group(sb, entry->efd_group);
2847 kmem_cache_free(ext4_free_data_cachep, entry);
2848 ext4_mb_unload_buddy(&e4b);
2849
2850 mb_debug(1, "freed %u blocks in %u structures\n", count, count2);
2851}
2852
2853int __init ext4_init_mballoc(void)
2854{
2855 ext4_pspace_cachep = KMEM_CACHE(ext4_prealloc_space,
2856 SLAB_RECLAIM_ACCOUNT);
2857 if (ext4_pspace_cachep == NULL)
2858 return -ENOMEM;
2859
2860 ext4_ac_cachep = KMEM_CACHE(ext4_allocation_context,
2861 SLAB_RECLAIM_ACCOUNT);
2862 if (ext4_ac_cachep == NULL) {
2863 kmem_cache_destroy(ext4_pspace_cachep);
2864 return -ENOMEM;
2865 }
2866
2867 ext4_free_data_cachep = KMEM_CACHE(ext4_free_data,
2868 SLAB_RECLAIM_ACCOUNT);
2869 if (ext4_free_data_cachep == NULL) {
2870 kmem_cache_destroy(ext4_pspace_cachep);
2871 kmem_cache_destroy(ext4_ac_cachep);
2872 return -ENOMEM;
2873 }
2874 return 0;
2875}
2876
2877void ext4_exit_mballoc(void)
2878{
2879 /*
2880 * Wait for completion of call_rcu()'s on ext4_pspace_cachep
2881 * before destroying the slab cache.
2882 */
2883 rcu_barrier();
2884 kmem_cache_destroy(ext4_pspace_cachep);
2885 kmem_cache_destroy(ext4_ac_cachep);
2886 kmem_cache_destroy(ext4_free_data_cachep);
2887 ext4_groupinfo_destroy_slabs();
2888}
2889
2890
2891/*
2892 * Check quota and mark chosen space (ac->ac_b_ex) non-free in bitmaps
2893 * Returns 0 if success or error code
2894 */
2895static noinline_for_stack int
2896ext4_mb_mark_diskspace_used(struct ext4_allocation_context *ac,
2897 handle_t *handle, unsigned int reserv_clstrs)
2898{
2899 struct buffer_head *bitmap_bh = NULL;
2900 struct ext4_group_desc *gdp;
2901 struct buffer_head *gdp_bh;
2902 struct ext4_sb_info *sbi;
2903 struct super_block *sb;
2904 ext4_fsblk_t block;
2905 int err, len;
2906
2907 BUG_ON(ac->ac_status != AC_STATUS_FOUND);
2908 BUG_ON(ac->ac_b_ex.fe_len <= 0);
2909
2910 sb = ac->ac_sb;
2911 sbi = EXT4_SB(sb);
2912
2913 bitmap_bh = ext4_read_block_bitmap(sb, ac->ac_b_ex.fe_group);
2914 if (IS_ERR(bitmap_bh)) {
2915 err = PTR_ERR(bitmap_bh);
2916 bitmap_bh = NULL;
2917 goto out_err;
2918 }
2919
2920 BUFFER_TRACE(bitmap_bh, "getting write access");
2921 err = ext4_journal_get_write_access(handle, bitmap_bh);
2922 if (err)
2923 goto out_err;
2924
2925 err = -EIO;
2926 gdp = ext4_get_group_desc(sb, ac->ac_b_ex.fe_group, &gdp_bh);
2927 if (!gdp)
2928 goto out_err;
2929
2930 ext4_debug("using block group %u(%d)\n", ac->ac_b_ex.fe_group,
2931 ext4_free_group_clusters(sb, gdp));
2932
2933 BUFFER_TRACE(gdp_bh, "get_write_access");
2934 err = ext4_journal_get_write_access(handle, gdp_bh);
2935 if (err)
2936 goto out_err;
2937
2938 block = ext4_grp_offs_to_block(sb, &ac->ac_b_ex);
2939
2940 len = EXT4_C2B(sbi, ac->ac_b_ex.fe_len);
2941 if (!ext4_data_block_valid(sbi, block, len)) {
2942 ext4_error(sb, "Allocating blocks %llu-%llu which overlap "
2943 "fs metadata", block, block+len);
2944 /* File system mounted not to panic on error
2945 * Fix the bitmap and return EFSCORRUPTED
2946 * We leak some of the blocks here.
2947 */
2948 ext4_lock_group(sb, ac->ac_b_ex.fe_group);
2949 ext4_set_bits(bitmap_bh->b_data, ac->ac_b_ex.fe_start,
2950 ac->ac_b_ex.fe_len);
2951 ext4_unlock_group(sb, ac->ac_b_ex.fe_group);
2952 err = ext4_handle_dirty_metadata(handle, NULL, bitmap_bh);
2953 if (!err)
2954 err = -EFSCORRUPTED;
2955 goto out_err;
2956 }
2957
2958 ext4_lock_group(sb, ac->ac_b_ex.fe_group);
2959#ifdef AGGRESSIVE_CHECK
2960 {
2961 int i;
2962 for (i = 0; i < ac->ac_b_ex.fe_len; i++) {
2963 BUG_ON(mb_test_bit(ac->ac_b_ex.fe_start + i,
2964 bitmap_bh->b_data));
2965 }
2966 }
2967#endif
2968 ext4_set_bits(bitmap_bh->b_data, ac->ac_b_ex.fe_start,
2969 ac->ac_b_ex.fe_len);
2970 if (gdp->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) {
2971 gdp->bg_flags &= cpu_to_le16(~EXT4_BG_BLOCK_UNINIT);
2972 ext4_free_group_clusters_set(sb, gdp,
2973 ext4_free_clusters_after_init(sb,
2974 ac->ac_b_ex.fe_group, gdp));
2975 }
2976 len = ext4_free_group_clusters(sb, gdp) - ac->ac_b_ex.fe_len;
2977 ext4_free_group_clusters_set(sb, gdp, len);
2978 ext4_block_bitmap_csum_set(sb, ac->ac_b_ex.fe_group, gdp, bitmap_bh);
2979 ext4_group_desc_csum_set(sb, ac->ac_b_ex.fe_group, gdp);
2980
2981 ext4_unlock_group(sb, ac->ac_b_ex.fe_group);
2982 percpu_counter_sub(&sbi->s_freeclusters_counter, ac->ac_b_ex.fe_len);
2983 /*
2984 * Now reduce the dirty block count also. Should not go negative
2985 */
2986 if (!(ac->ac_flags & EXT4_MB_DELALLOC_RESERVED))
2987 /* release all the reserved blocks if non delalloc */
2988 percpu_counter_sub(&sbi->s_dirtyclusters_counter,
2989 reserv_clstrs);
2990
2991 if (sbi->s_log_groups_per_flex) {
2992 ext4_group_t flex_group = ext4_flex_group(sbi,
2993 ac->ac_b_ex.fe_group);
2994 atomic64_sub(ac->ac_b_ex.fe_len,
2995 &sbi->s_flex_groups[flex_group].free_clusters);
2996 }
2997
2998 err = ext4_handle_dirty_metadata(handle, NULL, bitmap_bh);
2999 if (err)
3000 goto out_err;
3001 err = ext4_handle_dirty_metadata(handle, NULL, gdp_bh);
3002
3003out_err:
3004 brelse(bitmap_bh);
3005 return err;
3006}
3007
3008/*
3009 * here we normalize request for locality group
3010 * Group request are normalized to s_mb_group_prealloc, which goes to
3011 * s_strip if we set the same via mount option.
3012 * s_mb_group_prealloc can be configured via
3013 * /sys/fs/ext4/<partition>/mb_group_prealloc
3014 *
3015 * XXX: should we try to preallocate more than the group has now?
3016 */
3017static void ext4_mb_normalize_group_request(struct ext4_allocation_context *ac)
3018{
3019 struct super_block *sb = ac->ac_sb;
3020 struct ext4_locality_group *lg = ac->ac_lg;
3021
3022 BUG_ON(lg == NULL);
3023 ac->ac_g_ex.fe_len = EXT4_SB(sb)->s_mb_group_prealloc;
3024 mb_debug(1, "#%u: goal %u blocks for locality group\n",
3025 current->pid, ac->ac_g_ex.fe_len);
3026}
3027
3028/*
3029 * Normalization means making request better in terms of
3030 * size and alignment
3031 */
3032static noinline_for_stack void
3033ext4_mb_normalize_request(struct ext4_allocation_context *ac,
3034 struct ext4_allocation_request *ar)
3035{
3036 struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
3037 int bsbits, max;
3038 ext4_lblk_t end;
3039 loff_t size, start_off;
3040 loff_t orig_size __maybe_unused;
3041 ext4_lblk_t start;
3042 struct ext4_inode_info *ei = EXT4_I(ac->ac_inode);
3043 struct ext4_prealloc_space *pa;
3044
3045 /* do normalize only data requests, metadata requests
3046 do not need preallocation */
3047 if (!(ac->ac_flags & EXT4_MB_HINT_DATA))
3048 return;
3049
3050 /* sometime caller may want exact blocks */
3051 if (unlikely(ac->ac_flags & EXT4_MB_HINT_GOAL_ONLY))
3052 return;
3053
3054 /* caller may indicate that preallocation isn't
3055 * required (it's a tail, for example) */
3056 if (ac->ac_flags & EXT4_MB_HINT_NOPREALLOC)
3057 return;
3058
3059 if (ac->ac_flags & EXT4_MB_HINT_GROUP_ALLOC) {
3060 ext4_mb_normalize_group_request(ac);
3061 return ;
3062 }
3063
3064 bsbits = ac->ac_sb->s_blocksize_bits;
3065
3066 /* first, let's learn actual file size
3067 * given current request is allocated */
3068 size = ac->ac_o_ex.fe_logical + EXT4_C2B(sbi, ac->ac_o_ex.fe_len);
3069 size = size << bsbits;
3070 if (size < i_size_read(ac->ac_inode))
3071 size = i_size_read(ac->ac_inode);
3072 orig_size = size;
3073
3074 /* max size of free chunks */
3075 max = 2 << bsbits;
3076
3077#define NRL_CHECK_SIZE(req, size, max, chunk_size) \
3078 (req <= (size) || max <= (chunk_size))
3079
3080 /* first, try to predict filesize */
3081 /* XXX: should this table be tunable? */
3082 start_off = 0;
3083 if (size <= 16 * 1024) {
3084 size = 16 * 1024;
3085 } else if (size <= 32 * 1024) {
3086 size = 32 * 1024;
3087 } else if (size <= 64 * 1024) {
3088 size = 64 * 1024;
3089 } else if (size <= 128 * 1024) {
3090 size = 128 * 1024;
3091 } else if (size <= 256 * 1024) {
3092 size = 256 * 1024;
3093 } else if (size <= 512 * 1024) {
3094 size = 512 * 1024;
3095 } else if (size <= 1024 * 1024) {
3096 size = 1024 * 1024;
3097 } else if (NRL_CHECK_SIZE(size, 4 * 1024 * 1024, max, 2 * 1024)) {
3098 start_off = ((loff_t)ac->ac_o_ex.fe_logical >>
3099 (21 - bsbits)) << 21;
3100 size = 2 * 1024 * 1024;
3101 } else if (NRL_CHECK_SIZE(size, 8 * 1024 * 1024, max, 4 * 1024)) {
3102 start_off = ((loff_t)ac->ac_o_ex.fe_logical >>
3103 (22 - bsbits)) << 22;
3104 size = 4 * 1024 * 1024;
3105 } else if (NRL_CHECK_SIZE(ac->ac_o_ex.fe_len,
3106 (8<<20)>>bsbits, max, 8 * 1024)) {
3107 start_off = ((loff_t)ac->ac_o_ex.fe_logical >>
3108 (23 - bsbits)) << 23;
3109 size = 8 * 1024 * 1024;
3110 } else {
3111 start_off = (loff_t) ac->ac_o_ex.fe_logical << bsbits;
3112 size = (loff_t) EXT4_C2B(EXT4_SB(ac->ac_sb),
3113 ac->ac_o_ex.fe_len) << bsbits;
3114 }
3115 size = size >> bsbits;
3116 start = start_off >> bsbits;
3117
3118 /* don't cover already allocated blocks in selected range */
3119 if (ar->pleft && start <= ar->lleft) {
3120 size -= ar->lleft + 1 - start;
3121 start = ar->lleft + 1;
3122 }
3123 if (ar->pright && start + size - 1 >= ar->lright)
3124 size -= start + size - ar->lright;
3125
3126 /*
3127 * Trim allocation request for filesystems with artificially small
3128 * groups.
3129 */
3130 if (size > EXT4_BLOCKS_PER_GROUP(ac->ac_sb))
3131 size = EXT4_BLOCKS_PER_GROUP(ac->ac_sb);
3132
3133 end = start + size;
3134
3135 /* check we don't cross already preallocated blocks */
3136 rcu_read_lock();
3137 list_for_each_entry_rcu(pa, &ei->i_prealloc_list, pa_inode_list) {
3138 ext4_lblk_t pa_end;
3139
3140 if (pa->pa_deleted)
3141 continue;
3142 spin_lock(&pa->pa_lock);
3143 if (pa->pa_deleted) {
3144 spin_unlock(&pa->pa_lock);
3145 continue;
3146 }
3147
3148 pa_end = pa->pa_lstart + EXT4_C2B(EXT4_SB(ac->ac_sb),
3149 pa->pa_len);
3150
3151 /* PA must not overlap original request */
3152 BUG_ON(!(ac->ac_o_ex.fe_logical >= pa_end ||
3153 ac->ac_o_ex.fe_logical < pa->pa_lstart));
3154
3155 /* skip PAs this normalized request doesn't overlap with */
3156 if (pa->pa_lstart >= end || pa_end <= start) {
3157 spin_unlock(&pa->pa_lock);
3158 continue;
3159 }
3160 BUG_ON(pa->pa_lstart <= start && pa_end >= end);
3161
3162 /* adjust start or end to be adjacent to this pa */
3163 if (pa_end <= ac->ac_o_ex.fe_logical) {
3164 BUG_ON(pa_end < start);
3165 start = pa_end;
3166 } else if (pa->pa_lstart > ac->ac_o_ex.fe_logical) {
3167 BUG_ON(pa->pa_lstart > end);
3168 end = pa->pa_lstart;
3169 }
3170 spin_unlock(&pa->pa_lock);
3171 }
3172 rcu_read_unlock();
3173 size = end - start;
3174
3175 /* XXX: extra loop to check we really don't overlap preallocations */
3176 rcu_read_lock();
3177 list_for_each_entry_rcu(pa, &ei->i_prealloc_list, pa_inode_list) {
3178 ext4_lblk_t pa_end;
3179
3180 spin_lock(&pa->pa_lock);
3181 if (pa->pa_deleted == 0) {
3182 pa_end = pa->pa_lstart + EXT4_C2B(EXT4_SB(ac->ac_sb),
3183 pa->pa_len);
3184 BUG_ON(!(start >= pa_end || end <= pa->pa_lstart));
3185 }
3186 spin_unlock(&pa->pa_lock);
3187 }
3188 rcu_read_unlock();
3189
3190 if (start + size <= ac->ac_o_ex.fe_logical &&
3191 start > ac->ac_o_ex.fe_logical) {
3192 ext4_msg(ac->ac_sb, KERN_ERR,
3193 "start %lu, size %lu, fe_logical %lu",
3194 (unsigned long) start, (unsigned long) size,
3195 (unsigned long) ac->ac_o_ex.fe_logical);
3196 BUG();
3197 }
3198 BUG_ON(size <= 0 || size > EXT4_BLOCKS_PER_GROUP(ac->ac_sb));
3199
3200 /* now prepare goal request */
3201
3202 /* XXX: is it better to align blocks WRT to logical
3203 * placement or satisfy big request as is */
3204 ac->ac_g_ex.fe_logical = start;
3205 ac->ac_g_ex.fe_len = EXT4_NUM_B2C(sbi, size);
3206
3207 /* define goal start in order to merge */
3208 if (ar->pright && (ar->lright == (start + size))) {
3209 /* merge to the right */
3210 ext4_get_group_no_and_offset(ac->ac_sb, ar->pright - size,
3211 &ac->ac_f_ex.fe_group,
3212 &ac->ac_f_ex.fe_start);
3213 ac->ac_flags |= EXT4_MB_HINT_TRY_GOAL;
3214 }
3215 if (ar->pleft && (ar->lleft + 1 == start)) {
3216 /* merge to the left */
3217 ext4_get_group_no_and_offset(ac->ac_sb, ar->pleft + 1,
3218 &ac->ac_f_ex.fe_group,
3219 &ac->ac_f_ex.fe_start);
3220 ac->ac_flags |= EXT4_MB_HINT_TRY_GOAL;
3221 }
3222
3223 mb_debug(1, "goal: %u(was %u) blocks at %u\n", (unsigned) size,
3224 (unsigned) orig_size, (unsigned) start);
3225}
3226
3227static void ext4_mb_collect_stats(struct ext4_allocation_context *ac)
3228{
3229 struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
3230
3231 if (sbi->s_mb_stats && ac->ac_g_ex.fe_len > 1) {
3232 atomic_inc(&sbi->s_bal_reqs);
3233 atomic_add(ac->ac_b_ex.fe_len, &sbi->s_bal_allocated);
3234 if (ac->ac_b_ex.fe_len >= ac->ac_o_ex.fe_len)
3235 atomic_inc(&sbi->s_bal_success);
3236 atomic_add(ac->ac_found, &sbi->s_bal_ex_scanned);
3237 if (ac->ac_g_ex.fe_start == ac->ac_b_ex.fe_start &&
3238 ac->ac_g_ex.fe_group == ac->ac_b_ex.fe_group)
3239 atomic_inc(&sbi->s_bal_goals);
3240 if (ac->ac_found > sbi->s_mb_max_to_scan)
3241 atomic_inc(&sbi->s_bal_breaks);
3242 }
3243
3244 if (ac->ac_op == EXT4_MB_HISTORY_ALLOC)
3245 trace_ext4_mballoc_alloc(ac);
3246 else
3247 trace_ext4_mballoc_prealloc(ac);
3248}
3249
3250/*
3251 * Called on failure; free up any blocks from the inode PA for this
3252 * context. We don't need this for MB_GROUP_PA because we only change
3253 * pa_free in ext4_mb_release_context(), but on failure, we've already
3254 * zeroed out ac->ac_b_ex.fe_len, so group_pa->pa_free is not changed.
3255 */
3256static void ext4_discard_allocated_blocks(struct ext4_allocation_context *ac)
3257{
3258 struct ext4_prealloc_space *pa = ac->ac_pa;
3259 struct ext4_buddy e4b;
3260 int err;
3261
3262 if (pa == NULL) {
3263 if (ac->ac_f_ex.fe_len == 0)
3264 return;
3265 err = ext4_mb_load_buddy(ac->ac_sb, ac->ac_f_ex.fe_group, &e4b);
3266 if (err) {
3267 /*
3268 * This should never happen since we pin the
3269 * pages in the ext4_allocation_context so
3270 * ext4_mb_load_buddy() should never fail.
3271 */
3272 WARN(1, "mb_load_buddy failed (%d)", err);
3273 return;
3274 }
3275 ext4_lock_group(ac->ac_sb, ac->ac_f_ex.fe_group);
3276 mb_free_blocks(ac->ac_inode, &e4b, ac->ac_f_ex.fe_start,
3277 ac->ac_f_ex.fe_len);
3278 ext4_unlock_group(ac->ac_sb, ac->ac_f_ex.fe_group);
3279 ext4_mb_unload_buddy(&e4b);
3280 return;
3281 }
3282 if (pa->pa_type == MB_INODE_PA)
3283 pa->pa_free += ac->ac_b_ex.fe_len;
3284}
3285
3286/*
3287 * use blocks preallocated to inode
3288 */
3289static void ext4_mb_use_inode_pa(struct ext4_allocation_context *ac,
3290 struct ext4_prealloc_space *pa)
3291{
3292 struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
3293 ext4_fsblk_t start;
3294 ext4_fsblk_t end;
3295 int len;
3296
3297 /* found preallocated blocks, use them */
3298 start = pa->pa_pstart + (ac->ac_o_ex.fe_logical - pa->pa_lstart);
3299 end = min(pa->pa_pstart + EXT4_C2B(sbi, pa->pa_len),
3300 start + EXT4_C2B(sbi, ac->ac_o_ex.fe_len));
3301 len = EXT4_NUM_B2C(sbi, end - start);
3302 ext4_get_group_no_and_offset(ac->ac_sb, start, &ac->ac_b_ex.fe_group,
3303 &ac->ac_b_ex.fe_start);
3304 ac->ac_b_ex.fe_len = len;
3305 ac->ac_status = AC_STATUS_FOUND;
3306 ac->ac_pa = pa;
3307
3308 BUG_ON(start < pa->pa_pstart);
3309 BUG_ON(end > pa->pa_pstart + EXT4_C2B(sbi, pa->pa_len));
3310 BUG_ON(pa->pa_free < len);
3311 pa->pa_free -= len;
3312
3313 mb_debug(1, "use %llu/%u from inode pa %p\n", start, len, pa);
3314}
3315
3316/*
3317 * use blocks preallocated to locality group
3318 */
3319static void ext4_mb_use_group_pa(struct ext4_allocation_context *ac,
3320 struct ext4_prealloc_space *pa)
3321{
3322 unsigned int len = ac->ac_o_ex.fe_len;
3323
3324 ext4_get_group_no_and_offset(ac->ac_sb, pa->pa_pstart,
3325 &ac->ac_b_ex.fe_group,
3326 &ac->ac_b_ex.fe_start);
3327 ac->ac_b_ex.fe_len = len;
3328 ac->ac_status = AC_STATUS_FOUND;
3329 ac->ac_pa = pa;
3330
3331 /* we don't correct pa_pstart or pa_plen here to avoid
3332 * possible race when the group is being loaded concurrently
3333 * instead we correct pa later, after blocks are marked
3334 * in on-disk bitmap -- see ext4_mb_release_context()
3335 * Other CPUs are prevented from allocating from this pa by lg_mutex
3336 */
3337 mb_debug(1, "use %u/%u from group pa %p\n", pa->pa_lstart-len, len, pa);
3338}
3339
3340/*
3341 * Return the prealloc space that have minimal distance
3342 * from the goal block. @cpa is the prealloc
3343 * space that is having currently known minimal distance
3344 * from the goal block.
3345 */
3346static struct ext4_prealloc_space *
3347ext4_mb_check_group_pa(ext4_fsblk_t goal_block,
3348 struct ext4_prealloc_space *pa,
3349 struct ext4_prealloc_space *cpa)
3350{
3351 ext4_fsblk_t cur_distance, new_distance;
3352
3353 if (cpa == NULL) {
3354 atomic_inc(&pa->pa_count);
3355 return pa;
3356 }
3357 cur_distance = abs(goal_block - cpa->pa_pstart);
3358 new_distance = abs(goal_block - pa->pa_pstart);
3359
3360 if (cur_distance <= new_distance)
3361 return cpa;
3362
3363 /* drop the previous reference */
3364 atomic_dec(&cpa->pa_count);
3365 atomic_inc(&pa->pa_count);
3366 return pa;
3367}
3368
3369/*
3370 * search goal blocks in preallocated space
3371 */
3372static noinline_for_stack int
3373ext4_mb_use_preallocated(struct ext4_allocation_context *ac)
3374{
3375 struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
3376 int order, i;
3377 struct ext4_inode_info *ei = EXT4_I(ac->ac_inode);
3378 struct ext4_locality_group *lg;
3379 struct ext4_prealloc_space *pa, *cpa = NULL;
3380 ext4_fsblk_t goal_block;
3381
3382 /* only data can be preallocated */
3383 if (!(ac->ac_flags & EXT4_MB_HINT_DATA))
3384 return 0;
3385
3386 /* first, try per-file preallocation */
3387 rcu_read_lock();
3388 list_for_each_entry_rcu(pa, &ei->i_prealloc_list, pa_inode_list) {
3389
3390 /* all fields in this condition don't change,
3391 * so we can skip locking for them */
3392 if (ac->ac_o_ex.fe_logical < pa->pa_lstart ||
3393 ac->ac_o_ex.fe_logical >= (pa->pa_lstart +
3394 EXT4_C2B(sbi, pa->pa_len)))
3395 continue;
3396
3397 /* non-extent files can't have physical blocks past 2^32 */
3398 if (!(ext4_test_inode_flag(ac->ac_inode, EXT4_INODE_EXTENTS)) &&
3399 (pa->pa_pstart + EXT4_C2B(sbi, pa->pa_len) >
3400 EXT4_MAX_BLOCK_FILE_PHYS))
3401 continue;
3402
3403 /* found preallocated blocks, use them */
3404 spin_lock(&pa->pa_lock);
3405 if (pa->pa_deleted == 0 && pa->pa_free) {
3406 atomic_inc(&pa->pa_count);
3407 ext4_mb_use_inode_pa(ac, pa);
3408 spin_unlock(&pa->pa_lock);
3409 ac->ac_criteria = 10;
3410 rcu_read_unlock();
3411 return 1;
3412 }
3413 spin_unlock(&pa->pa_lock);
3414 }
3415 rcu_read_unlock();
3416
3417 /* can we use group allocation? */
3418 if (!(ac->ac_flags & EXT4_MB_HINT_GROUP_ALLOC))
3419 return 0;
3420
3421 /* inode may have no locality group for some reason */
3422 lg = ac->ac_lg;
3423 if (lg == NULL)
3424 return 0;
3425 order = fls(ac->ac_o_ex.fe_len) - 1;
3426 if (order > PREALLOC_TB_SIZE - 1)
3427 /* The max size of hash table is PREALLOC_TB_SIZE */
3428 order = PREALLOC_TB_SIZE - 1;
3429
3430 goal_block = ext4_grp_offs_to_block(ac->ac_sb, &ac->ac_g_ex);
3431 /*
3432 * search for the prealloc space that is having
3433 * minimal distance from the goal block.
3434 */
3435 for (i = order; i < PREALLOC_TB_SIZE; i++) {
3436 rcu_read_lock();
3437 list_for_each_entry_rcu(pa, &lg->lg_prealloc_list[i],
3438 pa_inode_list) {
3439 spin_lock(&pa->pa_lock);
3440 if (pa->pa_deleted == 0 &&
3441 pa->pa_free >= ac->ac_o_ex.fe_len) {
3442
3443 cpa = ext4_mb_check_group_pa(goal_block,
3444 pa, cpa);
3445 }
3446 spin_unlock(&pa->pa_lock);
3447 }
3448 rcu_read_unlock();
3449 }
3450 if (cpa) {
3451 ext4_mb_use_group_pa(ac, cpa);
3452 ac->ac_criteria = 20;
3453 return 1;
3454 }
3455 return 0;
3456}
3457
3458/*
3459 * the function goes through all block freed in the group
3460 * but not yet committed and marks them used in in-core bitmap.
3461 * buddy must be generated from this bitmap
3462 * Need to be called with the ext4 group lock held
3463 */
3464static void ext4_mb_generate_from_freelist(struct super_block *sb, void *bitmap,
3465 ext4_group_t group)
3466{
3467 struct rb_node *n;
3468 struct ext4_group_info *grp;
3469 struct ext4_free_data *entry;
3470
3471 grp = ext4_get_group_info(sb, group);
3472 n = rb_first(&(grp->bb_free_root));
3473
3474 while (n) {
3475 entry = rb_entry(n, struct ext4_free_data, efd_node);
3476 ext4_set_bits(bitmap, entry->efd_start_cluster, entry->efd_count);
3477 n = rb_next(n);
3478 }
3479 return;
3480}
3481
3482/*
3483 * the function goes through all preallocation in this group and marks them
3484 * used in in-core bitmap. buddy must be generated from this bitmap
3485 * Need to be called with ext4 group lock held
3486 */
3487static noinline_for_stack
3488void ext4_mb_generate_from_pa(struct super_block *sb, void *bitmap,
3489 ext4_group_t group)
3490{
3491 struct ext4_group_info *grp = ext4_get_group_info(sb, group);
3492 struct ext4_prealloc_space *pa;
3493 struct list_head *cur;
3494 ext4_group_t groupnr;
3495 ext4_grpblk_t start;
3496 int preallocated = 0;
3497 int len;
3498
3499 /* all form of preallocation discards first load group,
3500 * so the only competing code is preallocation use.
3501 * we don't need any locking here
3502 * notice we do NOT ignore preallocations with pa_deleted
3503 * otherwise we could leave used blocks available for
3504 * allocation in buddy when concurrent ext4_mb_put_pa()
3505 * is dropping preallocation
3506 */
3507 list_for_each(cur, &grp->bb_prealloc_list) {
3508 pa = list_entry(cur, struct ext4_prealloc_space, pa_group_list);
3509 spin_lock(&pa->pa_lock);
3510 ext4_get_group_no_and_offset(sb, pa->pa_pstart,
3511 &groupnr, &start);
3512 len = pa->pa_len;
3513 spin_unlock(&pa->pa_lock);
3514 if (unlikely(len == 0))
3515 continue;
3516 BUG_ON(groupnr != group);
3517 ext4_set_bits(bitmap, start, len);
3518 preallocated += len;
3519 }
3520 mb_debug(1, "prellocated %u for group %u\n", preallocated, group);
3521}
3522
3523static void ext4_mb_pa_callback(struct rcu_head *head)
3524{
3525 struct ext4_prealloc_space *pa;
3526 pa = container_of(head, struct ext4_prealloc_space, u.pa_rcu);
3527
3528 BUG_ON(atomic_read(&pa->pa_count));
3529 BUG_ON(pa->pa_deleted == 0);
3530 kmem_cache_free(ext4_pspace_cachep, pa);
3531}
3532
3533/*
3534 * drops a reference to preallocated space descriptor
3535 * if this was the last reference and the space is consumed
3536 */
3537static void ext4_mb_put_pa(struct ext4_allocation_context *ac,
3538 struct super_block *sb, struct ext4_prealloc_space *pa)
3539{
3540 ext4_group_t grp;
3541 ext4_fsblk_t grp_blk;
3542
3543 /* in this short window concurrent discard can set pa_deleted */
3544 spin_lock(&pa->pa_lock);
3545 if (!atomic_dec_and_test(&pa->pa_count) || pa->pa_free != 0) {
3546 spin_unlock(&pa->pa_lock);
3547 return;
3548 }
3549
3550 if (pa->pa_deleted == 1) {
3551 spin_unlock(&pa->pa_lock);
3552 return;
3553 }
3554
3555 pa->pa_deleted = 1;
3556 spin_unlock(&pa->pa_lock);
3557
3558 grp_blk = pa->pa_pstart;
3559 /*
3560 * If doing group-based preallocation, pa_pstart may be in the
3561 * next group when pa is used up
3562 */
3563 if (pa->pa_type == MB_GROUP_PA)
3564 grp_blk--;
3565
3566 grp = ext4_get_group_number(sb, grp_blk);
3567
3568 /*
3569 * possible race:
3570 *
3571 * P1 (buddy init) P2 (regular allocation)
3572 * find block B in PA
3573 * copy on-disk bitmap to buddy
3574 * mark B in on-disk bitmap
3575 * drop PA from group
3576 * mark all PAs in buddy
3577 *
3578 * thus, P1 initializes buddy with B available. to prevent this
3579 * we make "copy" and "mark all PAs" atomic and serialize "drop PA"
3580 * against that pair
3581 */
3582 ext4_lock_group(sb, grp);
3583 list_del(&pa->pa_group_list);
3584 ext4_unlock_group(sb, grp);
3585
3586 spin_lock(pa->pa_obj_lock);
3587 list_del_rcu(&pa->pa_inode_list);
3588 spin_unlock(pa->pa_obj_lock);
3589
3590 call_rcu(&(pa)->u.pa_rcu, ext4_mb_pa_callback);
3591}
3592
3593/*
3594 * creates new preallocated space for given inode
3595 */
3596static noinline_for_stack int
3597ext4_mb_new_inode_pa(struct ext4_allocation_context *ac)
3598{
3599 struct super_block *sb = ac->ac_sb;
3600 struct ext4_sb_info *sbi = EXT4_SB(sb);
3601 struct ext4_prealloc_space *pa;
3602 struct ext4_group_info *grp;
3603 struct ext4_inode_info *ei;
3604
3605 /* preallocate only when found space is larger then requested */
3606 BUG_ON(ac->ac_o_ex.fe_len >= ac->ac_b_ex.fe_len);
3607 BUG_ON(ac->ac_status != AC_STATUS_FOUND);
3608 BUG_ON(!S_ISREG(ac->ac_inode->i_mode));
3609
3610 pa = kmem_cache_alloc(ext4_pspace_cachep, GFP_NOFS);
3611 if (pa == NULL)
3612 return -ENOMEM;
3613
3614 if (ac->ac_b_ex.fe_len < ac->ac_g_ex.fe_len) {
3615 int winl;
3616 int wins;
3617 int win;
3618 int offs;
3619
3620 /* we can't allocate as much as normalizer wants.
3621 * so, found space must get proper lstart
3622 * to cover original request */
3623 BUG_ON(ac->ac_g_ex.fe_logical > ac->ac_o_ex.fe_logical);
3624 BUG_ON(ac->ac_g_ex.fe_len < ac->ac_o_ex.fe_len);
3625
3626 /* we're limited by original request in that
3627 * logical block must be covered any way
3628 * winl is window we can move our chunk within */
3629 winl = ac->ac_o_ex.fe_logical - ac->ac_g_ex.fe_logical;
3630
3631 /* also, we should cover whole original request */
3632 wins = EXT4_C2B(sbi, ac->ac_b_ex.fe_len - ac->ac_o_ex.fe_len);
3633
3634 /* the smallest one defines real window */
3635 win = min(winl, wins);
3636
3637 offs = ac->ac_o_ex.fe_logical %
3638 EXT4_C2B(sbi, ac->ac_b_ex.fe_len);
3639 if (offs && offs < win)
3640 win = offs;
3641
3642 ac->ac_b_ex.fe_logical = ac->ac_o_ex.fe_logical -
3643 EXT4_NUM_B2C(sbi, win);
3644 BUG_ON(ac->ac_o_ex.fe_logical < ac->ac_b_ex.fe_logical);
3645 BUG_ON(ac->ac_o_ex.fe_len > ac->ac_b_ex.fe_len);
3646 }
3647
3648 /* preallocation can change ac_b_ex, thus we store actually
3649 * allocated blocks for history */
3650 ac->ac_f_ex = ac->ac_b_ex;
3651
3652 pa->pa_lstart = ac->ac_b_ex.fe_logical;
3653 pa->pa_pstart = ext4_grp_offs_to_block(sb, &ac->ac_b_ex);
3654 pa->pa_len = ac->ac_b_ex.fe_len;
3655 pa->pa_free = pa->pa_len;
3656 atomic_set(&pa->pa_count, 1);
3657 spin_lock_init(&pa->pa_lock);
3658 INIT_LIST_HEAD(&pa->pa_inode_list);
3659 INIT_LIST_HEAD(&pa->pa_group_list);
3660 pa->pa_deleted = 0;
3661 pa->pa_type = MB_INODE_PA;
3662
3663 mb_debug(1, "new inode pa %p: %llu/%u for %u\n", pa,
3664 pa->pa_pstart, pa->pa_len, pa->pa_lstart);
3665 trace_ext4_mb_new_inode_pa(ac, pa);
3666
3667 ext4_mb_use_inode_pa(ac, pa);
3668 atomic_add(pa->pa_free, &sbi->s_mb_preallocated);
3669
3670 ei = EXT4_I(ac->ac_inode);
3671 grp = ext4_get_group_info(sb, ac->ac_b_ex.fe_group);
3672
3673 pa->pa_obj_lock = &ei->i_prealloc_lock;
3674 pa->pa_inode = ac->ac_inode;
3675
3676 ext4_lock_group(sb, ac->ac_b_ex.fe_group);
3677 list_add(&pa->pa_group_list, &grp->bb_prealloc_list);
3678 ext4_unlock_group(sb, ac->ac_b_ex.fe_group);
3679
3680 spin_lock(pa->pa_obj_lock);
3681 list_add_rcu(&pa->pa_inode_list, &ei->i_prealloc_list);
3682 spin_unlock(pa->pa_obj_lock);
3683
3684 return 0;
3685}
3686
3687/*
3688 * creates new preallocated space for locality group inodes belongs to
3689 */
3690static noinline_for_stack int
3691ext4_mb_new_group_pa(struct ext4_allocation_context *ac)
3692{
3693 struct super_block *sb = ac->ac_sb;
3694 struct ext4_locality_group *lg;
3695 struct ext4_prealloc_space *pa;
3696 struct ext4_group_info *grp;
3697
3698 /* preallocate only when found space is larger then requested */
3699 BUG_ON(ac->ac_o_ex.fe_len >= ac->ac_b_ex.fe_len);
3700 BUG_ON(ac->ac_status != AC_STATUS_FOUND);
3701 BUG_ON(!S_ISREG(ac->ac_inode->i_mode));
3702
3703 BUG_ON(ext4_pspace_cachep == NULL);
3704 pa = kmem_cache_alloc(ext4_pspace_cachep, GFP_NOFS);
3705 if (pa == NULL)
3706 return -ENOMEM;
3707
3708 /* preallocation can change ac_b_ex, thus we store actually
3709 * allocated blocks for history */
3710 ac->ac_f_ex = ac->ac_b_ex;
3711
3712 pa->pa_pstart = ext4_grp_offs_to_block(sb, &ac->ac_b_ex);
3713 pa->pa_lstart = pa->pa_pstart;
3714 pa->pa_len = ac->ac_b_ex.fe_len;
3715 pa->pa_free = pa->pa_len;
3716 atomic_set(&pa->pa_count, 1);
3717 spin_lock_init(&pa->pa_lock);
3718 INIT_LIST_HEAD(&pa->pa_inode_list);
3719 INIT_LIST_HEAD(&pa->pa_group_list);
3720 pa->pa_deleted = 0;
3721 pa->pa_type = MB_GROUP_PA;
3722
3723 mb_debug(1, "new group pa %p: %llu/%u for %u\n", pa,
3724 pa->pa_pstart, pa->pa_len, pa->pa_lstart);
3725 trace_ext4_mb_new_group_pa(ac, pa);
3726
3727 ext4_mb_use_group_pa(ac, pa);
3728 atomic_add(pa->pa_free, &EXT4_SB(sb)->s_mb_preallocated);
3729
3730 grp = ext4_get_group_info(sb, ac->ac_b_ex.fe_group);
3731 lg = ac->ac_lg;
3732 BUG_ON(lg == NULL);
3733
3734 pa->pa_obj_lock = &lg->lg_prealloc_lock;
3735 pa->pa_inode = NULL;
3736
3737 ext4_lock_group(sb, ac->ac_b_ex.fe_group);
3738 list_add(&pa->pa_group_list, &grp->bb_prealloc_list);
3739 ext4_unlock_group(sb, ac->ac_b_ex.fe_group);
3740
3741 /*
3742 * We will later add the new pa to the right bucket
3743 * after updating the pa_free in ext4_mb_release_context
3744 */
3745 return 0;
3746}
3747
3748static int ext4_mb_new_preallocation(struct ext4_allocation_context *ac)
3749{
3750 int err;
3751
3752 if (ac->ac_flags & EXT4_MB_HINT_GROUP_ALLOC)
3753 err = ext4_mb_new_group_pa(ac);
3754 else
3755 err = ext4_mb_new_inode_pa(ac);
3756 return err;
3757}
3758
3759/*
3760 * finds all unused blocks in on-disk bitmap, frees them in
3761 * in-core bitmap and buddy.
3762 * @pa must be unlinked from inode and group lists, so that
3763 * nobody else can find/use it.
3764 * the caller MUST hold group/inode locks.
3765 * TODO: optimize the case when there are no in-core structures yet
3766 */
3767static noinline_for_stack int
3768ext4_mb_release_inode_pa(struct ext4_buddy *e4b, struct buffer_head *bitmap_bh,
3769 struct ext4_prealloc_space *pa)
3770{
3771 struct super_block *sb = e4b->bd_sb;
3772 struct ext4_sb_info *sbi = EXT4_SB(sb);
3773 unsigned int end;
3774 unsigned int next;
3775 ext4_group_t group;
3776 ext4_grpblk_t bit;
3777 unsigned long long grp_blk_start;
3778 int err = 0;
3779 int free = 0;
3780
3781 BUG_ON(pa->pa_deleted == 0);
3782 ext4_get_group_no_and_offset(sb, pa->pa_pstart, &group, &bit);
3783 grp_blk_start = pa->pa_pstart - EXT4_C2B(sbi, bit);
3784 BUG_ON(group != e4b->bd_group && pa->pa_len != 0);
3785 end = bit + pa->pa_len;
3786
3787 while (bit < end) {
3788 bit = mb_find_next_zero_bit(bitmap_bh->b_data, end, bit);
3789 if (bit >= end)
3790 break;
3791 next = mb_find_next_bit(bitmap_bh->b_data, end, bit);
3792 mb_debug(1, " free preallocated %u/%u in group %u\n",
3793 (unsigned) ext4_group_first_block_no(sb, group) + bit,
3794 (unsigned) next - bit, (unsigned) group);
3795 free += next - bit;
3796
3797 trace_ext4_mballoc_discard(sb, NULL, group, bit, next - bit);
3798 trace_ext4_mb_release_inode_pa(pa, (grp_blk_start +
3799 EXT4_C2B(sbi, bit)),
3800 next - bit);
3801 mb_free_blocks(pa->pa_inode, e4b, bit, next - bit);
3802 bit = next + 1;
3803 }
3804 if (free != pa->pa_free) {
3805 ext4_msg(e4b->bd_sb, KERN_CRIT,
3806 "pa %p: logic %lu, phys. %lu, len %lu",
3807 pa, (unsigned long) pa->pa_lstart,
3808 (unsigned long) pa->pa_pstart,
3809 (unsigned long) pa->pa_len);
3810 ext4_grp_locked_error(sb, group, 0, 0, "free %u, pa_free %u",
3811 free, pa->pa_free);
3812 /*
3813 * pa is already deleted so we use the value obtained
3814 * from the bitmap and continue.
3815 */
3816 }
3817 atomic_add(free, &sbi->s_mb_discarded);
3818
3819 return err;
3820}
3821
3822static noinline_for_stack int
3823ext4_mb_release_group_pa(struct ext4_buddy *e4b,
3824 struct ext4_prealloc_space *pa)
3825{
3826 struct super_block *sb = e4b->bd_sb;
3827 ext4_group_t group;
3828 ext4_grpblk_t bit;
3829
3830 trace_ext4_mb_release_group_pa(sb, pa);
3831 BUG_ON(pa->pa_deleted == 0);
3832 ext4_get_group_no_and_offset(sb, pa->pa_pstart, &group, &bit);
3833 BUG_ON(group != e4b->bd_group && pa->pa_len != 0);
3834 mb_free_blocks(pa->pa_inode, e4b, bit, pa->pa_len);
3835 atomic_add(pa->pa_len, &EXT4_SB(sb)->s_mb_discarded);
3836 trace_ext4_mballoc_discard(sb, NULL, group, bit, pa->pa_len);
3837
3838 return 0;
3839}
3840
3841/*
3842 * releases all preallocations in given group
3843 *
3844 * first, we need to decide discard policy:
3845 * - when do we discard
3846 * 1) ENOSPC
3847 * - how many do we discard
3848 * 1) how many requested
3849 */
3850static noinline_for_stack int
3851ext4_mb_discard_group_preallocations(struct super_block *sb,
3852 ext4_group_t group, int needed)
3853{
3854 struct ext4_group_info *grp = ext4_get_group_info(sb, group);
3855 struct buffer_head *bitmap_bh = NULL;
3856 struct ext4_prealloc_space *pa, *tmp;
3857 struct list_head list;
3858 struct ext4_buddy e4b;
3859 int err;
3860 int busy = 0;
3861 int free = 0;
3862
3863 mb_debug(1, "discard preallocation for group %u\n", group);
3864
3865 if (list_empty(&grp->bb_prealloc_list))
3866 return 0;
3867
3868 bitmap_bh = ext4_read_block_bitmap(sb, group);
3869 if (IS_ERR(bitmap_bh)) {
3870 err = PTR_ERR(bitmap_bh);
3871 ext4_error(sb, "Error %d reading block bitmap for %u",
3872 err, group);
3873 return 0;
3874 }
3875
3876 err = ext4_mb_load_buddy(sb, group, &e4b);
3877 if (err) {
3878 ext4_error(sb, "Error loading buddy information for %u", group);
3879 put_bh(bitmap_bh);
3880 return 0;
3881 }
3882
3883 if (needed == 0)
3884 needed = EXT4_CLUSTERS_PER_GROUP(sb) + 1;
3885
3886 INIT_LIST_HEAD(&list);
3887repeat:
3888 ext4_lock_group(sb, group);
3889 list_for_each_entry_safe(pa, tmp,
3890 &grp->bb_prealloc_list, pa_group_list) {
3891 spin_lock(&pa->pa_lock);
3892 if (atomic_read(&pa->pa_count)) {
3893 spin_unlock(&pa->pa_lock);
3894 busy = 1;
3895 continue;
3896 }
3897 if (pa->pa_deleted) {
3898 spin_unlock(&pa->pa_lock);
3899 continue;
3900 }
3901
3902 /* seems this one can be freed ... */
3903 pa->pa_deleted = 1;
3904
3905 /* we can trust pa_free ... */
3906 free += pa->pa_free;
3907
3908 spin_unlock(&pa->pa_lock);
3909
3910 list_del(&pa->pa_group_list);
3911 list_add(&pa->u.pa_tmp_list, &list);
3912 }
3913
3914 /* if we still need more blocks and some PAs were used, try again */
3915 if (free < needed && busy) {
3916 busy = 0;
3917 ext4_unlock_group(sb, group);
3918 cond_resched();
3919 goto repeat;
3920 }
3921
3922 /* found anything to free? */
3923 if (list_empty(&list)) {
3924 BUG_ON(free != 0);
3925 goto out;
3926 }
3927
3928 /* now free all selected PAs */
3929 list_for_each_entry_safe(pa, tmp, &list, u.pa_tmp_list) {
3930
3931 /* remove from object (inode or locality group) */
3932 spin_lock(pa->pa_obj_lock);
3933 list_del_rcu(&pa->pa_inode_list);
3934 spin_unlock(pa->pa_obj_lock);
3935
3936 if (pa->pa_type == MB_GROUP_PA)
3937 ext4_mb_release_group_pa(&e4b, pa);
3938 else
3939 ext4_mb_release_inode_pa(&e4b, bitmap_bh, pa);
3940
3941 list_del(&pa->u.pa_tmp_list);
3942 call_rcu(&(pa)->u.pa_rcu, ext4_mb_pa_callback);
3943 }
3944
3945out:
3946 ext4_unlock_group(sb, group);
3947 ext4_mb_unload_buddy(&e4b);
3948 put_bh(bitmap_bh);
3949 return free;
3950}
3951
3952/*
3953 * releases all non-used preallocated blocks for given inode
3954 *
3955 * It's important to discard preallocations under i_data_sem
3956 * We don't want another block to be served from the prealloc
3957 * space when we are discarding the inode prealloc space.
3958 *
3959 * FIXME!! Make sure it is valid at all the call sites
3960 */
3961void ext4_discard_preallocations(struct inode *inode)
3962{
3963 struct ext4_inode_info *ei = EXT4_I(inode);
3964 struct super_block *sb = inode->i_sb;
3965 struct buffer_head *bitmap_bh = NULL;
3966 struct ext4_prealloc_space *pa, *tmp;
3967 ext4_group_t group = 0;
3968 struct list_head list;
3969 struct ext4_buddy e4b;
3970 int err;
3971
3972 if (!S_ISREG(inode->i_mode)) {
3973 /*BUG_ON(!list_empty(&ei->i_prealloc_list));*/
3974 return;
3975 }
3976
3977 mb_debug(1, "discard preallocation for inode %lu\n", inode->i_ino);
3978 trace_ext4_discard_preallocations(inode);
3979
3980 INIT_LIST_HEAD(&list);
3981
3982repeat:
3983 /* first, collect all pa's in the inode */
3984 spin_lock(&ei->i_prealloc_lock);
3985 while (!list_empty(&ei->i_prealloc_list)) {
3986 pa = list_entry(ei->i_prealloc_list.next,
3987 struct ext4_prealloc_space, pa_inode_list);
3988 BUG_ON(pa->pa_obj_lock != &ei->i_prealloc_lock);
3989 spin_lock(&pa->pa_lock);
3990 if (atomic_read(&pa->pa_count)) {
3991 /* this shouldn't happen often - nobody should
3992 * use preallocation while we're discarding it */
3993 spin_unlock(&pa->pa_lock);
3994 spin_unlock(&ei->i_prealloc_lock);
3995 ext4_msg(sb, KERN_ERR,
3996 "uh-oh! used pa while discarding");
3997 WARN_ON(1);
3998 schedule_timeout_uninterruptible(HZ);
3999 goto repeat;
4000
4001 }
4002 if (pa->pa_deleted == 0) {
4003 pa->pa_deleted = 1;
4004 spin_unlock(&pa->pa_lock);
4005 list_del_rcu(&pa->pa_inode_list);
4006 list_add(&pa->u.pa_tmp_list, &list);
4007 continue;
4008 }
4009
4010 /* someone is deleting pa right now */
4011 spin_unlock(&pa->pa_lock);
4012 spin_unlock(&ei->i_prealloc_lock);
4013
4014 /* we have to wait here because pa_deleted
4015 * doesn't mean pa is already unlinked from
4016 * the list. as we might be called from
4017 * ->clear_inode() the inode will get freed
4018 * and concurrent thread which is unlinking
4019 * pa from inode's list may access already
4020 * freed memory, bad-bad-bad */
4021
4022 /* XXX: if this happens too often, we can
4023 * add a flag to force wait only in case
4024 * of ->clear_inode(), but not in case of
4025 * regular truncate */
4026 schedule_timeout_uninterruptible(HZ);
4027 goto repeat;
4028 }
4029 spin_unlock(&ei->i_prealloc_lock);
4030
4031 list_for_each_entry_safe(pa, tmp, &list, u.pa_tmp_list) {
4032 BUG_ON(pa->pa_type != MB_INODE_PA);
4033 group = ext4_get_group_number(sb, pa->pa_pstart);
4034
4035 err = ext4_mb_load_buddy(sb, group, &e4b);
4036 if (err) {
4037 ext4_error(sb, "Error loading buddy information for %u",
4038 group);
4039 continue;
4040 }
4041
4042 bitmap_bh = ext4_read_block_bitmap(sb, group);
4043 if (IS_ERR(bitmap_bh)) {
4044 err = PTR_ERR(bitmap_bh);
4045 ext4_error(sb, "Error %d reading block bitmap for %u",
4046 err, group);
4047 ext4_mb_unload_buddy(&e4b);
4048 continue;
4049 }
4050
4051 ext4_lock_group(sb, group);
4052 list_del(&pa->pa_group_list);
4053 ext4_mb_release_inode_pa(&e4b, bitmap_bh, pa);
4054 ext4_unlock_group(sb, group);
4055
4056 ext4_mb_unload_buddy(&e4b);
4057 put_bh(bitmap_bh);
4058
4059 list_del(&pa->u.pa_tmp_list);
4060 call_rcu(&(pa)->u.pa_rcu, ext4_mb_pa_callback);
4061 }
4062}
4063
4064#ifdef CONFIG_EXT4_DEBUG
4065static void ext4_mb_show_ac(struct ext4_allocation_context *ac)
4066{
4067 struct super_block *sb = ac->ac_sb;
4068 ext4_group_t ngroups, i;
4069
4070 if (!ext4_mballoc_debug ||
4071 (EXT4_SB(sb)->s_mount_flags & EXT4_MF_FS_ABORTED))
4072 return;
4073
4074 ext4_msg(ac->ac_sb, KERN_ERR, "Can't allocate:"
4075 " Allocation context details:");
4076 ext4_msg(ac->ac_sb, KERN_ERR, "status %d flags %d",
4077 ac->ac_status, ac->ac_flags);
4078 ext4_msg(ac->ac_sb, KERN_ERR, "orig %lu/%lu/%lu@%lu, "
4079 "goal %lu/%lu/%lu@%lu, "
4080 "best %lu/%lu/%lu@%lu cr %d",
4081 (unsigned long)ac->ac_o_ex.fe_group,
4082 (unsigned long)ac->ac_o_ex.fe_start,
4083 (unsigned long)ac->ac_o_ex.fe_len,
4084 (unsigned long)ac->ac_o_ex.fe_logical,
4085 (unsigned long)ac->ac_g_ex.fe_group,
4086 (unsigned long)ac->ac_g_ex.fe_start,
4087 (unsigned long)ac->ac_g_ex.fe_len,
4088 (unsigned long)ac->ac_g_ex.fe_logical,
4089 (unsigned long)ac->ac_b_ex.fe_group,
4090 (unsigned long)ac->ac_b_ex.fe_start,
4091 (unsigned long)ac->ac_b_ex.fe_len,
4092 (unsigned long)ac->ac_b_ex.fe_logical,
4093 (int)ac->ac_criteria);
4094 ext4_msg(ac->ac_sb, KERN_ERR, "%d found", ac->ac_found);
4095 ext4_msg(ac->ac_sb, KERN_ERR, "groups: ");
4096 ngroups = ext4_get_groups_count(sb);
4097 for (i = 0; i < ngroups; i++) {
4098 struct ext4_group_info *grp = ext4_get_group_info(sb, i);
4099 struct ext4_prealloc_space *pa;
4100 ext4_grpblk_t start;
4101 struct list_head *cur;
4102 ext4_lock_group(sb, i);
4103 list_for_each(cur, &grp->bb_prealloc_list) {
4104 pa = list_entry(cur, struct ext4_prealloc_space,
4105 pa_group_list);
4106 spin_lock(&pa->pa_lock);
4107 ext4_get_group_no_and_offset(sb, pa->pa_pstart,
4108 NULL, &start);
4109 spin_unlock(&pa->pa_lock);
4110 printk(KERN_ERR "PA:%u:%d:%u \n", i,
4111 start, pa->pa_len);
4112 }
4113 ext4_unlock_group(sb, i);
4114
4115 if (grp->bb_free == 0)
4116 continue;
4117 printk(KERN_ERR "%u: %d/%d \n",
4118 i, grp->bb_free, grp->bb_fragments);
4119 }
4120 printk(KERN_ERR "\n");
4121}
4122#else
4123static inline void ext4_mb_show_ac(struct ext4_allocation_context *ac)
4124{
4125 return;
4126}
4127#endif
4128
4129/*
4130 * We use locality group preallocation for small size file. The size of the
4131 * file is determined by the current size or the resulting size after
4132 * allocation which ever is larger
4133 *
4134 * One can tune this size via /sys/fs/ext4/<partition>/mb_stream_req
4135 */
4136static void ext4_mb_group_or_file(struct ext4_allocation_context *ac)
4137{
4138 struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
4139 int bsbits = ac->ac_sb->s_blocksize_bits;
4140 loff_t size, isize;
4141
4142 if (!(ac->ac_flags & EXT4_MB_HINT_DATA))
4143 return;
4144
4145 if (unlikely(ac->ac_flags & EXT4_MB_HINT_GOAL_ONLY))
4146 return;
4147
4148 size = ac->ac_o_ex.fe_logical + EXT4_C2B(sbi, ac->ac_o_ex.fe_len);
4149 isize = (i_size_read(ac->ac_inode) + ac->ac_sb->s_blocksize - 1)
4150 >> bsbits;
4151
4152 if ((size == isize) &&
4153 !ext4_fs_is_busy(sbi) &&
4154 (atomic_read(&ac->ac_inode->i_writecount) == 0)) {
4155 ac->ac_flags |= EXT4_MB_HINT_NOPREALLOC;
4156 return;
4157 }
4158
4159 if (sbi->s_mb_group_prealloc <= 0) {
4160 ac->ac_flags |= EXT4_MB_STREAM_ALLOC;
4161 return;
4162 }
4163
4164 /* don't use group allocation for large files */
4165 size = max(size, isize);
4166 if (size > sbi->s_mb_stream_request) {
4167 ac->ac_flags |= EXT4_MB_STREAM_ALLOC;
4168 return;
4169 }
4170
4171 BUG_ON(ac->ac_lg != NULL);
4172 /*
4173 * locality group prealloc space are per cpu. The reason for having
4174 * per cpu locality group is to reduce the contention between block
4175 * request from multiple CPUs.
4176 */
4177 ac->ac_lg = raw_cpu_ptr(sbi->s_locality_groups);
4178
4179 /* we're going to use group allocation */
4180 ac->ac_flags |= EXT4_MB_HINT_GROUP_ALLOC;
4181
4182 /* serialize all allocations in the group */
4183 mutex_lock(&ac->ac_lg->lg_mutex);
4184}
4185
4186static noinline_for_stack int
4187ext4_mb_initialize_context(struct ext4_allocation_context *ac,
4188 struct ext4_allocation_request *ar)
4189{
4190 struct super_block *sb = ar->inode->i_sb;
4191 struct ext4_sb_info *sbi = EXT4_SB(sb);
4192 struct ext4_super_block *es = sbi->s_es;
4193 ext4_group_t group;
4194 unsigned int len;
4195 ext4_fsblk_t goal;
4196 ext4_grpblk_t block;
4197
4198 /* we can't allocate > group size */
4199 len = ar->len;
4200
4201 /* just a dirty hack to filter too big requests */
4202 if (len >= EXT4_CLUSTERS_PER_GROUP(sb))
4203 len = EXT4_CLUSTERS_PER_GROUP(sb);
4204
4205 /* start searching from the goal */
4206 goal = ar->goal;
4207 if (goal < le32_to_cpu(es->s_first_data_block) ||
4208 goal >= ext4_blocks_count(es))
4209 goal = le32_to_cpu(es->s_first_data_block);
4210 ext4_get_group_no_and_offset(sb, goal, &group, &block);
4211
4212 /* set up allocation goals */
4213 ac->ac_b_ex.fe_logical = EXT4_LBLK_CMASK(sbi, ar->logical);
4214 ac->ac_status = AC_STATUS_CONTINUE;
4215 ac->ac_sb = sb;
4216 ac->ac_inode = ar->inode;
4217 ac->ac_o_ex.fe_logical = ac->ac_b_ex.fe_logical;
4218 ac->ac_o_ex.fe_group = group;
4219 ac->ac_o_ex.fe_start = block;
4220 ac->ac_o_ex.fe_len = len;
4221 ac->ac_g_ex = ac->ac_o_ex;
4222 ac->ac_flags = ar->flags;
4223
4224 /* we have to define context: we'll we work with a file or
4225 * locality group. this is a policy, actually */
4226 ext4_mb_group_or_file(ac);
4227
4228 mb_debug(1, "init ac: %u blocks @ %u, goal %u, flags %x, 2^%d, "
4229 "left: %u/%u, right %u/%u to %swritable\n",
4230 (unsigned) ar->len, (unsigned) ar->logical,
4231 (unsigned) ar->goal, ac->ac_flags, ac->ac_2order,
4232 (unsigned) ar->lleft, (unsigned) ar->pleft,
4233 (unsigned) ar->lright, (unsigned) ar->pright,
4234 atomic_read(&ar->inode->i_writecount) ? "" : "non-");
4235 return 0;
4236
4237}
4238
4239static noinline_for_stack void
4240ext4_mb_discard_lg_preallocations(struct super_block *sb,
4241 struct ext4_locality_group *lg,
4242 int order, int total_entries)
4243{
4244 ext4_group_t group = 0;
4245 struct ext4_buddy e4b;
4246 struct list_head discard_list;
4247 struct ext4_prealloc_space *pa, *tmp;
4248
4249 mb_debug(1, "discard locality group preallocation\n");
4250
4251 INIT_LIST_HEAD(&discard_list);
4252
4253 spin_lock(&lg->lg_prealloc_lock);
4254 list_for_each_entry_rcu(pa, &lg->lg_prealloc_list[order],
4255 pa_inode_list) {
4256 spin_lock(&pa->pa_lock);
4257 if (atomic_read(&pa->pa_count)) {
4258 /*
4259 * This is the pa that we just used
4260 * for block allocation. So don't
4261 * free that
4262 */
4263 spin_unlock(&pa->pa_lock);
4264 continue;
4265 }
4266 if (pa->pa_deleted) {
4267 spin_unlock(&pa->pa_lock);
4268 continue;
4269 }
4270 /* only lg prealloc space */
4271 BUG_ON(pa->pa_type != MB_GROUP_PA);
4272
4273 /* seems this one can be freed ... */
4274 pa->pa_deleted = 1;
4275 spin_unlock(&pa->pa_lock);
4276
4277 list_del_rcu(&pa->pa_inode_list);
4278 list_add(&pa->u.pa_tmp_list, &discard_list);
4279
4280 total_entries--;
4281 if (total_entries <= 5) {
4282 /*
4283 * we want to keep only 5 entries
4284 * allowing it to grow to 8. This
4285 * mak sure we don't call discard
4286 * soon for this list.
4287 */
4288 break;
4289 }
4290 }
4291 spin_unlock(&lg->lg_prealloc_lock);
4292
4293 list_for_each_entry_safe(pa, tmp, &discard_list, u.pa_tmp_list) {
4294
4295 group = ext4_get_group_number(sb, pa->pa_pstart);
4296 if (ext4_mb_load_buddy(sb, group, &e4b)) {
4297 ext4_error(sb, "Error loading buddy information for %u",
4298 group);
4299 continue;
4300 }
4301 ext4_lock_group(sb, group);
4302 list_del(&pa->pa_group_list);
4303 ext4_mb_release_group_pa(&e4b, pa);
4304 ext4_unlock_group(sb, group);
4305
4306 ext4_mb_unload_buddy(&e4b);
4307 list_del(&pa->u.pa_tmp_list);
4308 call_rcu(&(pa)->u.pa_rcu, ext4_mb_pa_callback);
4309 }
4310}
4311
4312/*
4313 * We have incremented pa_count. So it cannot be freed at this
4314 * point. Also we hold lg_mutex. So no parallel allocation is
4315 * possible from this lg. That means pa_free cannot be updated.
4316 *
4317 * A parallel ext4_mb_discard_group_preallocations is possible.
4318 * which can cause the lg_prealloc_list to be updated.
4319 */
4320
4321static void ext4_mb_add_n_trim(struct ext4_allocation_context *ac)
4322{
4323 int order, added = 0, lg_prealloc_count = 1;
4324 struct super_block *sb = ac->ac_sb;
4325 struct ext4_locality_group *lg = ac->ac_lg;
4326 struct ext4_prealloc_space *tmp_pa, *pa = ac->ac_pa;
4327
4328 order = fls(pa->pa_free) - 1;
4329 if (order > PREALLOC_TB_SIZE - 1)
4330 /* The max size of hash table is PREALLOC_TB_SIZE */
4331 order = PREALLOC_TB_SIZE - 1;
4332 /* Add the prealloc space to lg */
4333 spin_lock(&lg->lg_prealloc_lock);
4334 list_for_each_entry_rcu(tmp_pa, &lg->lg_prealloc_list[order],
4335 pa_inode_list) {
4336 spin_lock(&tmp_pa->pa_lock);
4337 if (tmp_pa->pa_deleted) {
4338 spin_unlock(&tmp_pa->pa_lock);
4339 continue;
4340 }
4341 if (!added && pa->pa_free < tmp_pa->pa_free) {
4342 /* Add to the tail of the previous entry */
4343 list_add_tail_rcu(&pa->pa_inode_list,
4344 &tmp_pa->pa_inode_list);
4345 added = 1;
4346 /*
4347 * we want to count the total
4348 * number of entries in the list
4349 */
4350 }
4351 spin_unlock(&tmp_pa->pa_lock);
4352 lg_prealloc_count++;
4353 }
4354 if (!added)
4355 list_add_tail_rcu(&pa->pa_inode_list,
4356 &lg->lg_prealloc_list[order]);
4357 spin_unlock(&lg->lg_prealloc_lock);
4358
4359 /* Now trim the list to be not more than 8 elements */
4360 if (lg_prealloc_count > 8) {
4361 ext4_mb_discard_lg_preallocations(sb, lg,
4362 order, lg_prealloc_count);
4363 return;
4364 }
4365 return ;
4366}
4367
4368/*
4369 * release all resource we used in allocation
4370 */
4371static int ext4_mb_release_context(struct ext4_allocation_context *ac)
4372{
4373 struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
4374 struct ext4_prealloc_space *pa = ac->ac_pa;
4375 if (pa) {
4376 if (pa->pa_type == MB_GROUP_PA) {
4377 /* see comment in ext4_mb_use_group_pa() */
4378 spin_lock(&pa->pa_lock);
4379 pa->pa_pstart += EXT4_C2B(sbi, ac->ac_b_ex.fe_len);
4380 pa->pa_lstart += EXT4_C2B(sbi, ac->ac_b_ex.fe_len);
4381 pa->pa_free -= ac->ac_b_ex.fe_len;
4382 pa->pa_len -= ac->ac_b_ex.fe_len;
4383 spin_unlock(&pa->pa_lock);
4384 }
4385 }
4386 if (pa) {
4387 /*
4388 * We want to add the pa to the right bucket.
4389 * Remove it from the list and while adding
4390 * make sure the list to which we are adding
4391 * doesn't grow big.
4392 */
4393 if ((pa->pa_type == MB_GROUP_PA) && likely(pa->pa_free)) {
4394 spin_lock(pa->pa_obj_lock);
4395 list_del_rcu(&pa->pa_inode_list);
4396 spin_unlock(pa->pa_obj_lock);
4397 ext4_mb_add_n_trim(ac);
4398 }
4399 ext4_mb_put_pa(ac, ac->ac_sb, pa);
4400 }
4401 if (ac->ac_bitmap_page)
4402 put_page(ac->ac_bitmap_page);
4403 if (ac->ac_buddy_page)
4404 put_page(ac->ac_buddy_page);
4405 if (ac->ac_flags & EXT4_MB_HINT_GROUP_ALLOC)
4406 mutex_unlock(&ac->ac_lg->lg_mutex);
4407 ext4_mb_collect_stats(ac);
4408 return 0;
4409}
4410
4411static int ext4_mb_discard_preallocations(struct super_block *sb, int needed)
4412{
4413 ext4_group_t i, ngroups = ext4_get_groups_count(sb);
4414 int ret;
4415 int freed = 0;
4416
4417 trace_ext4_mb_discard_preallocations(sb, needed);
4418 for (i = 0; i < ngroups && needed > 0; i++) {
4419 ret = ext4_mb_discard_group_preallocations(sb, i, needed);
4420 freed += ret;
4421 needed -= ret;
4422 }
4423
4424 return freed;
4425}
4426
4427/*
4428 * Main entry point into mballoc to allocate blocks
4429 * it tries to use preallocation first, then falls back
4430 * to usual allocation
4431 */
4432ext4_fsblk_t ext4_mb_new_blocks(handle_t *handle,
4433 struct ext4_allocation_request *ar, int *errp)
4434{
4435 int freed;
4436 struct ext4_allocation_context *ac = NULL;
4437 struct ext4_sb_info *sbi;
4438 struct super_block *sb;
4439 ext4_fsblk_t block = 0;
4440 unsigned int inquota = 0;
4441 unsigned int reserv_clstrs = 0;
4442
4443 might_sleep();
4444 sb = ar->inode->i_sb;
4445 sbi = EXT4_SB(sb);
4446
4447 trace_ext4_request_blocks(ar);
4448
4449 /* Allow to use superuser reservation for quota file */
4450 if (IS_NOQUOTA(ar->inode))
4451 ar->flags |= EXT4_MB_USE_ROOT_BLOCKS;
4452
4453 if ((ar->flags & EXT4_MB_DELALLOC_RESERVED) == 0) {
4454 /* Without delayed allocation we need to verify
4455 * there is enough free blocks to do block allocation
4456 * and verify allocation doesn't exceed the quota limits.
4457 */
4458 while (ar->len &&
4459 ext4_claim_free_clusters(sbi, ar->len, ar->flags)) {
4460
4461 /* let others to free the space */
4462 cond_resched();
4463 ar->len = ar->len >> 1;
4464 }
4465 if (!ar->len) {
4466 *errp = -ENOSPC;
4467 return 0;
4468 }
4469 reserv_clstrs = ar->len;
4470 if (ar->flags & EXT4_MB_USE_ROOT_BLOCKS) {
4471 dquot_alloc_block_nofail(ar->inode,
4472 EXT4_C2B(sbi, ar->len));
4473 } else {
4474 while (ar->len &&
4475 dquot_alloc_block(ar->inode,
4476 EXT4_C2B(sbi, ar->len))) {
4477
4478 ar->flags |= EXT4_MB_HINT_NOPREALLOC;
4479 ar->len--;
4480 }
4481 }
4482 inquota = ar->len;
4483 if (ar->len == 0) {
4484 *errp = -EDQUOT;
4485 goto out;
4486 }
4487 }
4488
4489 ac = kmem_cache_zalloc(ext4_ac_cachep, GFP_NOFS);
4490 if (!ac) {
4491 ar->len = 0;
4492 *errp = -ENOMEM;
4493 goto out;
4494 }
4495
4496 *errp = ext4_mb_initialize_context(ac, ar);
4497 if (*errp) {
4498 ar->len = 0;
4499 goto out;
4500 }
4501
4502 ac->ac_op = EXT4_MB_HISTORY_PREALLOC;
4503 if (!ext4_mb_use_preallocated(ac)) {
4504 ac->ac_op = EXT4_MB_HISTORY_ALLOC;
4505 ext4_mb_normalize_request(ac, ar);
4506repeat:
4507 /* allocate space in core */
4508 *errp = ext4_mb_regular_allocator(ac);
4509 if (*errp)
4510 goto discard_and_exit;
4511
4512 /* as we've just preallocated more space than
4513 * user requested originally, we store allocated
4514 * space in a special descriptor */
4515 if (ac->ac_status == AC_STATUS_FOUND &&
4516 ac->ac_o_ex.fe_len < ac->ac_b_ex.fe_len)
4517 *errp = ext4_mb_new_preallocation(ac);
4518 if (*errp) {
4519 discard_and_exit:
4520 ext4_discard_allocated_blocks(ac);
4521 goto errout;
4522 }
4523 }
4524 if (likely(ac->ac_status == AC_STATUS_FOUND)) {
4525 *errp = ext4_mb_mark_diskspace_used(ac, handle, reserv_clstrs);
4526 if (*errp) {
4527 ext4_discard_allocated_blocks(ac);
4528 goto errout;
4529 } else {
4530 block = ext4_grp_offs_to_block(sb, &ac->ac_b_ex);
4531 ar->len = ac->ac_b_ex.fe_len;
4532 }
4533 } else {
4534 freed = ext4_mb_discard_preallocations(sb, ac->ac_o_ex.fe_len);
4535 if (freed)
4536 goto repeat;
4537 *errp = -ENOSPC;
4538 }
4539
4540errout:
4541 if (*errp) {
4542 ac->ac_b_ex.fe_len = 0;
4543 ar->len = 0;
4544 ext4_mb_show_ac(ac);
4545 }
4546 ext4_mb_release_context(ac);
4547out:
4548 if (ac)
4549 kmem_cache_free(ext4_ac_cachep, ac);
4550 if (inquota && ar->len < inquota)
4551 dquot_free_block(ar->inode, EXT4_C2B(sbi, inquota - ar->len));
4552 if (!ar->len) {
4553 if ((ar->flags & EXT4_MB_DELALLOC_RESERVED) == 0)
4554 /* release all the reserved blocks if non delalloc */
4555 percpu_counter_sub(&sbi->s_dirtyclusters_counter,
4556 reserv_clstrs);
4557 }
4558
4559 trace_ext4_allocate_blocks(ar, (unsigned long long)block);
4560
4561 return block;
4562}
4563
4564/*
4565 * We can merge two free data extents only if the physical blocks
4566 * are contiguous, AND the extents were freed by the same transaction,
4567 * AND the blocks are associated with the same group.
4568 */
4569static int can_merge(struct ext4_free_data *entry1,
4570 struct ext4_free_data *entry2)
4571{
4572 if ((entry1->efd_tid == entry2->efd_tid) &&
4573 (entry1->efd_group == entry2->efd_group) &&
4574 ((entry1->efd_start_cluster + entry1->efd_count) == entry2->efd_start_cluster))
4575 return 1;
4576 return 0;
4577}
4578
4579static noinline_for_stack int
4580ext4_mb_free_metadata(handle_t *handle, struct ext4_buddy *e4b,
4581 struct ext4_free_data *new_entry)
4582{
4583 ext4_group_t group = e4b->bd_group;
4584 ext4_grpblk_t cluster;
4585 ext4_grpblk_t clusters = new_entry->efd_count;
4586 struct ext4_free_data *entry;
4587 struct ext4_group_info *db = e4b->bd_info;
4588 struct super_block *sb = e4b->bd_sb;
4589 struct ext4_sb_info *sbi = EXT4_SB(sb);
4590 struct rb_node **n = &db->bb_free_root.rb_node, *node;
4591 struct rb_node *parent = NULL, *new_node;
4592
4593 BUG_ON(!ext4_handle_valid(handle));
4594 BUG_ON(e4b->bd_bitmap_page == NULL);
4595 BUG_ON(e4b->bd_buddy_page == NULL);
4596
4597 new_node = &new_entry->efd_node;
4598 cluster = new_entry->efd_start_cluster;
4599
4600 if (!*n) {
4601 /* first free block exent. We need to
4602 protect buddy cache from being freed,
4603 * otherwise we'll refresh it from
4604 * on-disk bitmap and lose not-yet-available
4605 * blocks */
4606 get_page(e4b->bd_buddy_page);
4607 get_page(e4b->bd_bitmap_page);
4608 }
4609 while (*n) {
4610 parent = *n;
4611 entry = rb_entry(parent, struct ext4_free_data, efd_node);
4612 if (cluster < entry->efd_start_cluster)
4613 n = &(*n)->rb_left;
4614 else if (cluster >= (entry->efd_start_cluster + entry->efd_count))
4615 n = &(*n)->rb_right;
4616 else {
4617 ext4_grp_locked_error(sb, group, 0,
4618 ext4_group_first_block_no(sb, group) +
4619 EXT4_C2B(sbi, cluster),
4620 "Block already on to-be-freed list");
4621 return 0;
4622 }
4623 }
4624
4625 rb_link_node(new_node, parent, n);
4626 rb_insert_color(new_node, &db->bb_free_root);
4627
4628 /* Now try to see the extent can be merged to left and right */
4629 node = rb_prev(new_node);
4630 if (node) {
4631 entry = rb_entry(node, struct ext4_free_data, efd_node);
4632 if (can_merge(entry, new_entry) &&
4633 ext4_journal_callback_try_del(handle, &entry->efd_jce)) {
4634 new_entry->efd_start_cluster = entry->efd_start_cluster;
4635 new_entry->efd_count += entry->efd_count;
4636 rb_erase(node, &(db->bb_free_root));
4637 kmem_cache_free(ext4_free_data_cachep, entry);
4638 }
4639 }
4640
4641 node = rb_next(new_node);
4642 if (node) {
4643 entry = rb_entry(node, struct ext4_free_data, efd_node);
4644 if (can_merge(new_entry, entry) &&
4645 ext4_journal_callback_try_del(handle, &entry->efd_jce)) {
4646 new_entry->efd_count += entry->efd_count;
4647 rb_erase(node, &(db->bb_free_root));
4648 kmem_cache_free(ext4_free_data_cachep, entry);
4649 }
4650 }
4651 /* Add the extent to transaction's private list */
4652 new_entry->efd_jce.jce_func = ext4_free_data_callback;
4653 spin_lock(&sbi->s_md_lock);
4654 _ext4_journal_callback_add(handle, &new_entry->efd_jce);
4655 sbi->s_mb_free_pending += clusters;
4656 spin_unlock(&sbi->s_md_lock);
4657 return 0;
4658}
4659
4660/**
4661 * ext4_free_blocks() -- Free given blocks and update quota
4662 * @handle: handle for this transaction
4663 * @inode: inode
4664 * @block: start physical block to free
4665 * @count: number of blocks to count
4666 * @flags: flags used by ext4_free_blocks
4667 */
4668void ext4_free_blocks(handle_t *handle, struct inode *inode,
4669 struct buffer_head *bh, ext4_fsblk_t block,
4670 unsigned long count, int flags)
4671{
4672 struct buffer_head *bitmap_bh = NULL;
4673 struct super_block *sb = inode->i_sb;
4674 struct ext4_group_desc *gdp;
4675 unsigned int overflow;
4676 ext4_grpblk_t bit;
4677 struct buffer_head *gd_bh;
4678 ext4_group_t block_group;
4679 struct ext4_sb_info *sbi;
4680 struct ext4_buddy e4b;
4681 unsigned int count_clusters;
4682 int err = 0;
4683 int ret;
4684
4685 might_sleep();
4686 if (bh) {
4687 if (block)
4688 BUG_ON(block != bh->b_blocknr);
4689 else
4690 block = bh->b_blocknr;
4691 }
4692
4693 sbi = EXT4_SB(sb);
4694 if (!(flags & EXT4_FREE_BLOCKS_VALIDATED) &&
4695 !ext4_data_block_valid(sbi, block, count)) {
4696 ext4_error(sb, "Freeing blocks not in datazone - "
4697 "block = %llu, count = %lu", block, count);
4698 goto error_return;
4699 }
4700
4701 ext4_debug("freeing block %llu\n", block);
4702 trace_ext4_free_blocks(inode, block, count, flags);
4703
4704 if (bh && (flags & EXT4_FREE_BLOCKS_FORGET)) {
4705 BUG_ON(count > 1);
4706
4707 ext4_forget(handle, flags & EXT4_FREE_BLOCKS_METADATA,
4708 inode, bh, block);
4709 }
4710
4711 /*
4712 * If the extent to be freed does not begin on a cluster
4713 * boundary, we need to deal with partial clusters at the
4714 * beginning and end of the extent. Normally we will free
4715 * blocks at the beginning or the end unless we are explicitly
4716 * requested to avoid doing so.
4717 */
4718 overflow = EXT4_PBLK_COFF(sbi, block);
4719 if (overflow) {
4720 if (flags & EXT4_FREE_BLOCKS_NOFREE_FIRST_CLUSTER) {
4721 overflow = sbi->s_cluster_ratio - overflow;
4722 block += overflow;
4723 if (count > overflow)
4724 count -= overflow;
4725 else
4726 return;
4727 } else {
4728 block -= overflow;
4729 count += overflow;
4730 }
4731 }
4732 overflow = EXT4_LBLK_COFF(sbi, count);
4733 if (overflow) {
4734 if (flags & EXT4_FREE_BLOCKS_NOFREE_LAST_CLUSTER) {
4735 if (count > overflow)
4736 count -= overflow;
4737 else
4738 return;
4739 } else
4740 count += sbi->s_cluster_ratio - overflow;
4741 }
4742
4743 if (!bh && (flags & EXT4_FREE_BLOCKS_FORGET)) {
4744 int i;
4745 int is_metadata = flags & EXT4_FREE_BLOCKS_METADATA;
4746
4747 for (i = 0; i < count; i++) {
4748 cond_resched();
4749 if (is_metadata)
4750 bh = sb_find_get_block(inode->i_sb, block + i);
4751 ext4_forget(handle, is_metadata, inode, bh, block + i);
4752 }
4753 }
4754
4755do_more:
4756 overflow = 0;
4757 ext4_get_group_no_and_offset(sb, block, &block_group, &bit);
4758
4759 if (unlikely(EXT4_MB_GRP_BBITMAP_CORRUPT(
4760 ext4_get_group_info(sb, block_group))))
4761 return;
4762
4763 /*
4764 * Check to see if we are freeing blocks across a group
4765 * boundary.
4766 */
4767 if (EXT4_C2B(sbi, bit) + count > EXT4_BLOCKS_PER_GROUP(sb)) {
4768 overflow = EXT4_C2B(sbi, bit) + count -
4769 EXT4_BLOCKS_PER_GROUP(sb);
4770 count -= overflow;
4771 }
4772 count_clusters = EXT4_NUM_B2C(sbi, count);
4773 bitmap_bh = ext4_read_block_bitmap(sb, block_group);
4774 if (IS_ERR(bitmap_bh)) {
4775 err = PTR_ERR(bitmap_bh);
4776 bitmap_bh = NULL;
4777 goto error_return;
4778 }
4779 gdp = ext4_get_group_desc(sb, block_group, &gd_bh);
4780 if (!gdp) {
4781 err = -EIO;
4782 goto error_return;
4783 }
4784
4785 if (in_range(ext4_block_bitmap(sb, gdp), block, count) ||
4786 in_range(ext4_inode_bitmap(sb, gdp), block, count) ||
4787 in_range(block, ext4_inode_table(sb, gdp),
4788 EXT4_SB(sb)->s_itb_per_group) ||
4789 in_range(block + count - 1, ext4_inode_table(sb, gdp),
4790 EXT4_SB(sb)->s_itb_per_group)) {
4791
4792 ext4_error(sb, "Freeing blocks in system zone - "
4793 "Block = %llu, count = %lu", block, count);
4794 /* err = 0. ext4_std_error should be a no op */
4795 goto error_return;
4796 }
4797
4798 BUFFER_TRACE(bitmap_bh, "getting write access");
4799 err = ext4_journal_get_write_access(handle, bitmap_bh);
4800 if (err)
4801 goto error_return;
4802
4803 /*
4804 * We are about to modify some metadata. Call the journal APIs
4805 * to unshare ->b_data if a currently-committing transaction is
4806 * using it
4807 */
4808 BUFFER_TRACE(gd_bh, "get_write_access");
4809 err = ext4_journal_get_write_access(handle, gd_bh);
4810 if (err)
4811 goto error_return;
4812#ifdef AGGRESSIVE_CHECK
4813 {
4814 int i;
4815 for (i = 0; i < count_clusters; i++)
4816 BUG_ON(!mb_test_bit(bit + i, bitmap_bh->b_data));
4817 }
4818#endif
4819 trace_ext4_mballoc_free(sb, inode, block_group, bit, count_clusters);
4820
4821 /* __GFP_NOFAIL: retry infinitely, ignore TIF_MEMDIE and memcg limit. */
4822 err = ext4_mb_load_buddy_gfp(sb, block_group, &e4b,
4823 GFP_NOFS|__GFP_NOFAIL);
4824 if (err)
4825 goto error_return;
4826
4827 /*
4828 * We need to make sure we don't reuse the freed block until after the
4829 * transaction is committed. We make an exception if the inode is to be
4830 * written in writeback mode since writeback mode has weak data
4831 * consistency guarantees.
4832 */
4833 if (ext4_handle_valid(handle) &&
4834 ((flags & EXT4_FREE_BLOCKS_METADATA) ||
4835 !ext4_should_writeback_data(inode))) {
4836 struct ext4_free_data *new_entry;
4837 /*
4838 * We use __GFP_NOFAIL because ext4_free_blocks() is not allowed
4839 * to fail.
4840 */
4841 new_entry = kmem_cache_alloc(ext4_free_data_cachep,
4842 GFP_NOFS|__GFP_NOFAIL);
4843 new_entry->efd_start_cluster = bit;
4844 new_entry->efd_group = block_group;
4845 new_entry->efd_count = count_clusters;
4846 new_entry->efd_tid = handle->h_transaction->t_tid;
4847
4848 ext4_lock_group(sb, block_group);
4849 mb_clear_bits(bitmap_bh->b_data, bit, count_clusters);
4850 ext4_mb_free_metadata(handle, &e4b, new_entry);
4851 } else {
4852 /* need to update group_info->bb_free and bitmap
4853 * with group lock held. generate_buddy look at
4854 * them with group lock_held
4855 */
4856 if (test_opt(sb, DISCARD)) {
4857 err = ext4_issue_discard(sb, block_group, bit, count);
4858 if (err && err != -EOPNOTSUPP)
4859 ext4_msg(sb, KERN_WARNING, "discard request in"
4860 " group:%d block:%d count:%lu failed"
4861 " with %d", block_group, bit, count,
4862 err);
4863 } else
4864 EXT4_MB_GRP_CLEAR_TRIMMED(e4b.bd_info);
4865
4866 ext4_lock_group(sb, block_group);
4867 mb_clear_bits(bitmap_bh->b_data, bit, count_clusters);
4868 mb_free_blocks(inode, &e4b, bit, count_clusters);
4869 }
4870
4871 ret = ext4_free_group_clusters(sb, gdp) + count_clusters;
4872 ext4_free_group_clusters_set(sb, gdp, ret);
4873 ext4_block_bitmap_csum_set(sb, block_group, gdp, bitmap_bh);
4874 ext4_group_desc_csum_set(sb, block_group, gdp);
4875 ext4_unlock_group(sb, block_group);
4876
4877 if (sbi->s_log_groups_per_flex) {
4878 ext4_group_t flex_group = ext4_flex_group(sbi, block_group);
4879 atomic64_add(count_clusters,
4880 &sbi->s_flex_groups[flex_group].free_clusters);
4881 }
4882
4883 if (!(flags & EXT4_FREE_BLOCKS_NO_QUOT_UPDATE))
4884 dquot_free_block(inode, EXT4_C2B(sbi, count_clusters));
4885 percpu_counter_add(&sbi->s_freeclusters_counter, count_clusters);
4886
4887 ext4_mb_unload_buddy(&e4b);
4888
4889 /* We dirtied the bitmap block */
4890 BUFFER_TRACE(bitmap_bh, "dirtied bitmap block");
4891 err = ext4_handle_dirty_metadata(handle, NULL, bitmap_bh);
4892
4893 /* And the group descriptor block */
4894 BUFFER_TRACE(gd_bh, "dirtied group descriptor block");
4895 ret = ext4_handle_dirty_metadata(handle, NULL, gd_bh);
4896 if (!err)
4897 err = ret;
4898
4899 if (overflow && !err) {
4900 block += count;
4901 count = overflow;
4902 put_bh(bitmap_bh);
4903 goto do_more;
4904 }
4905error_return:
4906 brelse(bitmap_bh);
4907 ext4_std_error(sb, err);
4908 return;
4909}
4910
4911/**
4912 * ext4_group_add_blocks() -- Add given blocks to an existing group
4913 * @handle: handle to this transaction
4914 * @sb: super block
4915 * @block: start physical block to add to the block group
4916 * @count: number of blocks to free
4917 *
4918 * This marks the blocks as free in the bitmap and buddy.
4919 */
4920int ext4_group_add_blocks(handle_t *handle, struct super_block *sb,
4921 ext4_fsblk_t block, unsigned long count)
4922{
4923 struct buffer_head *bitmap_bh = NULL;
4924 struct buffer_head *gd_bh;
4925 ext4_group_t block_group;
4926 ext4_grpblk_t bit;
4927 unsigned int i;
4928 struct ext4_group_desc *desc;
4929 struct ext4_sb_info *sbi = EXT4_SB(sb);
4930 struct ext4_buddy e4b;
4931 int err = 0, ret, blk_free_count;
4932 ext4_grpblk_t blocks_freed;
4933
4934 ext4_debug("Adding block(s) %llu-%llu\n", block, block + count - 1);
4935
4936 if (count == 0)
4937 return 0;
4938
4939 ext4_get_group_no_and_offset(sb, block, &block_group, &bit);
4940 /*
4941 * Check to see if we are freeing blocks across a group
4942 * boundary.
4943 */
4944 if (bit + count > EXT4_BLOCKS_PER_GROUP(sb)) {
4945 ext4_warning(sb, "too much blocks added to group %u",
4946 block_group);
4947 err = -EINVAL;
4948 goto error_return;
4949 }
4950
4951 bitmap_bh = ext4_read_block_bitmap(sb, block_group);
4952 if (IS_ERR(bitmap_bh)) {
4953 err = PTR_ERR(bitmap_bh);
4954 bitmap_bh = NULL;
4955 goto error_return;
4956 }
4957
4958 desc = ext4_get_group_desc(sb, block_group, &gd_bh);
4959 if (!desc) {
4960 err = -EIO;
4961 goto error_return;
4962 }
4963
4964 if (in_range(ext4_block_bitmap(sb, desc), block, count) ||
4965 in_range(ext4_inode_bitmap(sb, desc), block, count) ||
4966 in_range(block, ext4_inode_table(sb, desc), sbi->s_itb_per_group) ||
4967 in_range(block + count - 1, ext4_inode_table(sb, desc),
4968 sbi->s_itb_per_group)) {
4969 ext4_error(sb, "Adding blocks in system zones - "
4970 "Block = %llu, count = %lu",
4971 block, count);
4972 err = -EINVAL;
4973 goto error_return;
4974 }
4975
4976 BUFFER_TRACE(bitmap_bh, "getting write access");
4977 err = ext4_journal_get_write_access(handle, bitmap_bh);
4978 if (err)
4979 goto error_return;
4980
4981 /*
4982 * We are about to modify some metadata. Call the journal APIs
4983 * to unshare ->b_data if a currently-committing transaction is
4984 * using it
4985 */
4986 BUFFER_TRACE(gd_bh, "get_write_access");
4987 err = ext4_journal_get_write_access(handle, gd_bh);
4988 if (err)
4989 goto error_return;
4990
4991 for (i = 0, blocks_freed = 0; i < count; i++) {
4992 BUFFER_TRACE(bitmap_bh, "clear bit");
4993 if (!mb_test_bit(bit + i, bitmap_bh->b_data)) {
4994 ext4_error(sb, "bit already cleared for block %llu",
4995 (ext4_fsblk_t)(block + i));
4996 BUFFER_TRACE(bitmap_bh, "bit already cleared");
4997 } else {
4998 blocks_freed++;
4999 }
5000 }
5001
5002 err = ext4_mb_load_buddy(sb, block_group, &e4b);
5003 if (err)
5004 goto error_return;
5005
5006 /*
5007 * need to update group_info->bb_free and bitmap
5008 * with group lock held. generate_buddy look at
5009 * them with group lock_held
5010 */
5011 ext4_lock_group(sb, block_group);
5012 mb_clear_bits(bitmap_bh->b_data, bit, count);
5013 mb_free_blocks(NULL, &e4b, bit, count);
5014 blk_free_count = blocks_freed + ext4_free_group_clusters(sb, desc);
5015 ext4_free_group_clusters_set(sb, desc, blk_free_count);
5016 ext4_block_bitmap_csum_set(sb, block_group, desc, bitmap_bh);
5017 ext4_group_desc_csum_set(sb, block_group, desc);
5018 ext4_unlock_group(sb, block_group);
5019 percpu_counter_add(&sbi->s_freeclusters_counter,
5020 EXT4_NUM_B2C(sbi, blocks_freed));
5021
5022 if (sbi->s_log_groups_per_flex) {
5023 ext4_group_t flex_group = ext4_flex_group(sbi, block_group);
5024 atomic64_add(EXT4_NUM_B2C(sbi, blocks_freed),
5025 &sbi->s_flex_groups[flex_group].free_clusters);
5026 }
5027
5028 ext4_mb_unload_buddy(&e4b);
5029
5030 /* We dirtied the bitmap block */
5031 BUFFER_TRACE(bitmap_bh, "dirtied bitmap block");
5032 err = ext4_handle_dirty_metadata(handle, NULL, bitmap_bh);
5033
5034 /* And the group descriptor block */
5035 BUFFER_TRACE(gd_bh, "dirtied group descriptor block");
5036 ret = ext4_handle_dirty_metadata(handle, NULL, gd_bh);
5037 if (!err)
5038 err = ret;
5039
5040error_return:
5041 brelse(bitmap_bh);
5042 ext4_std_error(sb, err);
5043 return err;
5044}
5045
5046/**
5047 * ext4_trim_extent -- function to TRIM one single free extent in the group
5048 * @sb: super block for the file system
5049 * @start: starting block of the free extent in the alloc. group
5050 * @count: number of blocks to TRIM
5051 * @group: alloc. group we are working with
5052 * @e4b: ext4 buddy for the group
5053 *
5054 * Trim "count" blocks starting at "start" in the "group". To assure that no
5055 * one will allocate those blocks, mark it as used in buddy bitmap. This must
5056 * be called with under the group lock.
5057 */
5058static int ext4_trim_extent(struct super_block *sb, int start, int count,
5059 ext4_group_t group, struct ext4_buddy *e4b)
5060__releases(bitlock)
5061__acquires(bitlock)
5062{
5063 struct ext4_free_extent ex;
5064 int ret = 0;
5065
5066 trace_ext4_trim_extent(sb, group, start, count);
5067
5068 assert_spin_locked(ext4_group_lock_ptr(sb, group));
5069
5070 ex.fe_start = start;
5071 ex.fe_group = group;
5072 ex.fe_len = count;
5073
5074 /*
5075 * Mark blocks used, so no one can reuse them while
5076 * being trimmed.
5077 */
5078 mb_mark_used(e4b, &ex);
5079 ext4_unlock_group(sb, group);
5080 ret = ext4_issue_discard(sb, group, start, count);
5081 ext4_lock_group(sb, group);
5082 mb_free_blocks(NULL, e4b, start, ex.fe_len);
5083 return ret;
5084}
5085
5086/**
5087 * ext4_trim_all_free -- function to trim all free space in alloc. group
5088 * @sb: super block for file system
5089 * @group: group to be trimmed
5090 * @start: first group block to examine
5091 * @max: last group block to examine
5092 * @minblocks: minimum extent block count
5093 *
5094 * ext4_trim_all_free walks through group's buddy bitmap searching for free
5095 * extents. When the free block is found, ext4_trim_extent is called to TRIM
5096 * the extent.
5097 *
5098 *
5099 * ext4_trim_all_free walks through group's block bitmap searching for free
5100 * extents. When the free extent is found, mark it as used in group buddy
5101 * bitmap. Then issue a TRIM command on this extent and free the extent in
5102 * the group buddy bitmap. This is done until whole group is scanned.
5103 */
5104static ext4_grpblk_t
5105ext4_trim_all_free(struct super_block *sb, ext4_group_t group,
5106 ext4_grpblk_t start, ext4_grpblk_t max,
5107 ext4_grpblk_t minblocks)
5108{
5109 void *bitmap;
5110 ext4_grpblk_t next, count = 0, free_count = 0;
5111 struct ext4_buddy e4b;
5112 int ret = 0;
5113
5114 trace_ext4_trim_all_free(sb, group, start, max);
5115
5116 ret = ext4_mb_load_buddy(sb, group, &e4b);
5117 if (ret) {
5118 ext4_error(sb, "Error in loading buddy "
5119 "information for %u", group);
5120 return ret;
5121 }
5122 bitmap = e4b.bd_bitmap;
5123
5124 ext4_lock_group(sb, group);
5125 if (EXT4_MB_GRP_WAS_TRIMMED(e4b.bd_info) &&
5126 minblocks >= atomic_read(&EXT4_SB(sb)->s_last_trim_minblks))
5127 goto out;
5128
5129 start = (e4b.bd_info->bb_first_free > start) ?
5130 e4b.bd_info->bb_first_free : start;
5131
5132 while (start <= max) {
5133 start = mb_find_next_zero_bit(bitmap, max + 1, start);
5134 if (start > max)
5135 break;
5136 next = mb_find_next_bit(bitmap, max + 1, start);
5137
5138 if ((next - start) >= minblocks) {
5139 ret = ext4_trim_extent(sb, start,
5140 next - start, group, &e4b);
5141 if (ret && ret != -EOPNOTSUPP)
5142 break;
5143 ret = 0;
5144 count += next - start;
5145 }
5146 free_count += next - start;
5147 start = next + 1;
5148
5149 if (fatal_signal_pending(current)) {
5150 count = -ERESTARTSYS;
5151 break;
5152 }
5153
5154 if (need_resched()) {
5155 ext4_unlock_group(sb, group);
5156 cond_resched();
5157 ext4_lock_group(sb, group);
5158 }
5159
5160 if ((e4b.bd_info->bb_free - free_count) < minblocks)
5161 break;
5162 }
5163
5164 if (!ret) {
5165 ret = count;
5166 EXT4_MB_GRP_SET_TRIMMED(e4b.bd_info);
5167 }
5168out:
5169 ext4_unlock_group(sb, group);
5170 ext4_mb_unload_buddy(&e4b);
5171
5172 ext4_debug("trimmed %d blocks in the group %d\n",
5173 count, group);
5174
5175 return ret;
5176}
5177
5178/**
5179 * ext4_trim_fs() -- trim ioctl handle function
5180 * @sb: superblock for filesystem
5181 * @range: fstrim_range structure
5182 *
5183 * start: First Byte to trim
5184 * len: number of Bytes to trim from start
5185 * minlen: minimum extent length in Bytes
5186 * ext4_trim_fs goes through all allocation groups containing Bytes from
5187 * start to start+len. For each such a group ext4_trim_all_free function
5188 * is invoked to trim all free space.
5189 */
5190int ext4_trim_fs(struct super_block *sb, struct fstrim_range *range)
5191{
5192 struct ext4_group_info *grp;
5193 ext4_group_t group, first_group, last_group;
5194 ext4_grpblk_t cnt = 0, first_cluster, last_cluster;
5195 uint64_t start, end, minlen, trimmed = 0;
5196 ext4_fsblk_t first_data_blk =
5197 le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block);
5198 ext4_fsblk_t max_blks = ext4_blocks_count(EXT4_SB(sb)->s_es);
5199 int ret = 0;
5200
5201 start = range->start >> sb->s_blocksize_bits;
5202 end = start + (range->len >> sb->s_blocksize_bits) - 1;
5203 minlen = EXT4_NUM_B2C(EXT4_SB(sb),
5204 range->minlen >> sb->s_blocksize_bits);
5205
5206 if (minlen > EXT4_CLUSTERS_PER_GROUP(sb) ||
5207 start >= max_blks ||
5208 range->len < sb->s_blocksize)
5209 return -EINVAL;
5210 if (end >= max_blks)
5211 end = max_blks - 1;
5212 if (end <= first_data_blk)
5213 goto out;
5214 if (start < first_data_blk)
5215 start = first_data_blk;
5216
5217 /* Determine first and last group to examine based on start and end */
5218 ext4_get_group_no_and_offset(sb, (ext4_fsblk_t) start,
5219 &first_group, &first_cluster);
5220 ext4_get_group_no_and_offset(sb, (ext4_fsblk_t) end,
5221 &last_group, &last_cluster);
5222
5223 /* end now represents the last cluster to discard in this group */
5224 end = EXT4_CLUSTERS_PER_GROUP(sb) - 1;
5225
5226 for (group = first_group; group <= last_group; group++) {
5227 grp = ext4_get_group_info(sb, group);
5228 /* We only do this if the grp has never been initialized */
5229 if (unlikely(EXT4_MB_GRP_NEED_INIT(grp))) {
5230 ret = ext4_mb_init_group(sb, group, GFP_NOFS);
5231 if (ret)
5232 break;
5233 }
5234
5235 /*
5236 * For all the groups except the last one, last cluster will
5237 * always be EXT4_CLUSTERS_PER_GROUP(sb)-1, so we only need to
5238 * change it for the last group, note that last_cluster is
5239 * already computed earlier by ext4_get_group_no_and_offset()
5240 */
5241 if (group == last_group)
5242 end = last_cluster;
5243
5244 if (grp->bb_free >= minlen) {
5245 cnt = ext4_trim_all_free(sb, group, first_cluster,
5246 end, minlen);
5247 if (cnt < 0) {
5248 ret = cnt;
5249 break;
5250 }
5251 trimmed += cnt;
5252 }
5253
5254 /*
5255 * For every group except the first one, we are sure
5256 * that the first cluster to discard will be cluster #0.
5257 */
5258 first_cluster = 0;
5259 }
5260
5261 if (!ret)
5262 atomic_set(&EXT4_SB(sb)->s_last_trim_minblks, minlen);
5263
5264out:
5265 range->len = EXT4_C2B(EXT4_SB(sb), trimmed) << sb->s_blocksize_bits;
5266 return ret;
5267}