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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 Licens
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/debugfs.h>
27#include <linux/slab.h>
28#include <trace/events/ext4.h>
29
30/*
31 * MUSTDO:
32 * - test ext4_ext_search_left() and ext4_ext_search_right()
33 * - search for metadata in few groups
34 *
35 * TODO v4:
36 * - normalization should take into account whether file is still open
37 * - discard preallocations if no free space left (policy?)
38 * - don't normalize tails
39 * - quota
40 * - reservation for superuser
41 *
42 * TODO v3:
43 * - bitmap read-ahead (proposed by Oleg Drokin aka green)
44 * - track min/max extents in each group for better group selection
45 * - mb_mark_used() may allocate chunk right after splitting buddy
46 * - tree of groups sorted by number of free blocks
47 * - error handling
48 */
49
50/*
51 * The allocation request involve request for multiple number of blocks
52 * near to the goal(block) value specified.
53 *
54 * During initialization phase of the allocator we decide to use the
55 * group preallocation or inode preallocation depending on the size of
56 * the file. The size of the file could be the resulting file size we
57 * would have after allocation, or the current file size, which ever
58 * is larger. If the size is less than sbi->s_mb_stream_request we
59 * select to use the group preallocation. The default value of
60 * s_mb_stream_request is 16 blocks. This can also be tuned via
61 * /sys/fs/ext4/<partition>/mb_stream_req. The value is represented in
62 * terms of number of blocks.
63 *
64 * The main motivation for having small file use group preallocation is to
65 * ensure that we have small files closer together on the disk.
66 *
67 * First stage the allocator looks at the inode prealloc list,
68 * ext4_inode_info->i_prealloc_list, which contains list of prealloc
69 * spaces for this particular inode. The inode prealloc space is
70 * represented as:
71 *
72 * pa_lstart -> the logical start block for this prealloc space
73 * pa_pstart -> the physical start block for this prealloc space
74 * pa_len -> length for this prealloc space (in clusters)
75 * pa_free -> free space available in this prealloc space (in clusters)
76 *
77 * The inode preallocation space is used looking at the _logical_ start
78 * block. If only the logical file block falls within the range of prealloc
79 * space we will consume the particular prealloc space. This makes sure that
80 * we have contiguous physical blocks representing the file blocks
81 *
82 * The important thing to be noted in case of inode prealloc space is that
83 * we don't modify the values associated to inode prealloc space except
84 * pa_free.
85 *
86 * If we are not able to find blocks in the inode prealloc space and if we
87 * have the group allocation flag set then we look at the locality group
88 * prealloc space. These are per CPU prealloc list represented as
89 *
90 * ext4_sb_info.s_locality_groups[smp_processor_id()]
91 *
92 * The reason for having a per cpu locality group is to reduce the contention
93 * between CPUs. It is possible to get scheduled at this point.
94 *
95 * The locality group prealloc space is used looking at whether we have
96 * enough free space (pa_free) within the prealloc space.
97 *
98 * If we can't allocate blocks via inode prealloc or/and locality group
99 * prealloc then we look at the buddy cache. The buddy cache is represented
100 * by ext4_sb_info.s_buddy_cache (struct inode) whose file offset gets
101 * mapped to the buddy and bitmap information regarding different
102 * groups. The buddy information is attached to buddy cache inode so that
103 * we can access them through the page cache. The information regarding
104 * each group is loaded via ext4_mb_load_buddy. The information involve
105 * block bitmap and buddy information. The information are stored in the
106 * inode as:
107 *
108 * { page }
109 * [ group 0 bitmap][ group 0 buddy] [group 1][ group 1]...
110 *
111 *
112 * one block each for bitmap and buddy information. So for each group we
113 * take up 2 blocks. A page can contain blocks_per_page (PAGE_CACHE_SIZE /
114 * blocksize) blocks. So it can have information regarding groups_per_page
115 * which is blocks_per_page/2
116 *
117 * The buddy cache inode is not stored on disk. The inode is thrown
118 * away when the filesystem is unmounted.
119 *
120 * We look for count number of blocks in the buddy cache. If we were able
121 * to locate that many free blocks we return with additional information
122 * regarding rest of the contiguous physical block available
123 *
124 * Before allocating blocks via buddy cache we normalize the request
125 * blocks. This ensure we ask for more blocks that we needed. The extra
126 * blocks that we get after allocation is added to the respective prealloc
127 * list. In case of inode preallocation we follow a list of heuristics
128 * based on file size. This can be found in ext4_mb_normalize_request. If
129 * we are doing a group prealloc we try to normalize the request to
130 * sbi->s_mb_group_prealloc. The default value of s_mb_group_prealloc is
131 * dependent on the cluster size; for non-bigalloc file systems, it is
132 * 512 blocks. This can be tuned via
133 * /sys/fs/ext4/<partition>/mb_group_prealloc. The value is represented in
134 * terms of number of blocks. If we have mounted the file system with -O
135 * stripe=<value> option the group prealloc request is normalized to the
136 * the smallest multiple of the stripe value (sbi->s_stripe) which is
137 * greater than the default mb_group_prealloc.
138 *
139 * The regular allocator (using the buddy cache) supports a few tunables.
140 *
141 * /sys/fs/ext4/<partition>/mb_min_to_scan
142 * /sys/fs/ext4/<partition>/mb_max_to_scan
143 * /sys/fs/ext4/<partition>/mb_order2_req
144 *
145 * The regular allocator uses buddy scan only if the request len is power of
146 * 2 blocks and the order of allocation is >= sbi->s_mb_order2_reqs. The
147 * value of s_mb_order2_reqs can be tuned via
148 * /sys/fs/ext4/<partition>/mb_order2_req. If the request len is equal to
149 * stripe size (sbi->s_stripe), we try to search for contiguous block in
150 * stripe size. This should result in better allocation on RAID setups. If
151 * not, we search in the specific group using bitmap for best extents. The
152 * tunable min_to_scan and max_to_scan control the behaviour here.
153 * min_to_scan indicate how long the mballoc __must__ look for a best
154 * extent and max_to_scan indicates how long the mballoc __can__ look for a
155 * best extent in the found extents. Searching for the blocks starts with
156 * the group specified as the goal value in allocation context via
157 * ac_g_ex. Each group is first checked based on the criteria whether it
158 * can be used for allocation. ext4_mb_good_group explains how the groups are
159 * checked.
160 *
161 * Both the prealloc space are getting populated as above. So for the first
162 * request we will hit the buddy cache which will result in this prealloc
163 * space getting filled. The prealloc space is then later used for the
164 * subsequent request.
165 */
166
167/*
168 * mballoc operates on the following data:
169 * - on-disk bitmap
170 * - in-core buddy (actually includes buddy and bitmap)
171 * - preallocation descriptors (PAs)
172 *
173 * there are two types of preallocations:
174 * - inode
175 * assiged to specific inode and can be used for this inode only.
176 * it describes part of inode's space preallocated to specific
177 * physical blocks. any block from that preallocated can be used
178 * independent. the descriptor just tracks number of blocks left
179 * unused. so, before taking some block from descriptor, one must
180 * make sure corresponded logical block isn't allocated yet. this
181 * also means that freeing any block within descriptor's range
182 * must discard all preallocated blocks.
183 * - locality group
184 * assigned to specific locality group which does not translate to
185 * permanent set of inodes: inode can join and leave group. space
186 * from this type of preallocation can be used for any inode. thus
187 * it's consumed from the beginning to the end.
188 *
189 * relation between them can be expressed as:
190 * in-core buddy = on-disk bitmap + preallocation descriptors
191 *
192 * this mean blocks mballoc considers used are:
193 * - allocated blocks (persistent)
194 * - preallocated blocks (non-persistent)
195 *
196 * consistency in mballoc world means that at any time a block is either
197 * free or used in ALL structures. notice: "any time" should not be read
198 * literally -- time is discrete and delimited by locks.
199 *
200 * to keep it simple, we don't use block numbers, instead we count number of
201 * blocks: how many blocks marked used/free in on-disk bitmap, buddy and PA.
202 *
203 * all operations can be expressed as:
204 * - init buddy: buddy = on-disk + PAs
205 * - new PA: buddy += N; PA = N
206 * - use inode PA: on-disk += N; PA -= N
207 * - discard inode PA buddy -= on-disk - PA; PA = 0
208 * - use locality group PA on-disk += N; PA -= N
209 * - discard locality group PA buddy -= PA; PA = 0
210 * note: 'buddy -= on-disk - PA' is used to show that on-disk bitmap
211 * is used in real operation because we can't know actual used
212 * bits from PA, only from on-disk bitmap
213 *
214 * if we follow this strict logic, then all operations above should be atomic.
215 * given some of them can block, we'd have to use something like semaphores
216 * killing performance on high-end SMP hardware. let's try to relax it using
217 * the following knowledge:
218 * 1) if buddy is referenced, it's already initialized
219 * 2) while block is used in buddy and the buddy is referenced,
220 * nobody can re-allocate that block
221 * 3) we work on bitmaps and '+' actually means 'set bits'. if on-disk has
222 * bit set and PA claims same block, it's OK. IOW, one can set bit in
223 * on-disk bitmap if buddy has same bit set or/and PA covers corresponded
224 * block
225 *
226 * so, now we're building a concurrency table:
227 * - init buddy vs.
228 * - new PA
229 * blocks for PA are allocated in the buddy, buddy must be referenced
230 * until PA is linked to allocation group to avoid concurrent buddy init
231 * - use inode PA
232 * we need to make sure that either on-disk bitmap or PA has uptodate data
233 * given (3) we care that PA-=N operation doesn't interfere with init
234 * - discard inode PA
235 * the simplest way would be to have buddy initialized by the discard
236 * - use locality group PA
237 * again PA-=N must be serialized with init
238 * - discard locality group PA
239 * the simplest way would be to have buddy initialized by the discard
240 * - new PA vs.
241 * - use inode PA
242 * i_data_sem serializes them
243 * - discard inode PA
244 * discard process must wait until PA isn't used by another process
245 * - use locality group PA
246 * some mutex should serialize them
247 * - discard locality group PA
248 * discard process must wait until PA isn't used by another process
249 * - use inode PA
250 * - use inode PA
251 * i_data_sem or another mutex should 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 * nothing wrong here -- they're different PAs covering different blocks
256 * - discard locality group PA
257 * discard process must wait until PA isn't used by another process
258 *
259 * now we're ready to make few consequences:
260 * - PA is referenced and while it is no discard is possible
261 * - PA is referenced until block isn't marked in on-disk bitmap
262 * - PA changes only after on-disk bitmap
263 * - discard must not compete with init. either init is done before
264 * any discard or they're serialized somehow
265 * - buddy init as sum of on-disk bitmap and PAs is done atomically
266 *
267 * a special case when we've used PA to emptiness. no need to modify buddy
268 * in this case, but we should care about concurrent init
269 *
270 */
271
272 /*
273 * Logic in few words:
274 *
275 * - allocation:
276 * load group
277 * find blocks
278 * mark bits in on-disk bitmap
279 * release group
280 *
281 * - use preallocation:
282 * find proper PA (per-inode or group)
283 * load group
284 * mark bits in on-disk bitmap
285 * release group
286 * release PA
287 *
288 * - free:
289 * load group
290 * mark bits in on-disk bitmap
291 * release group
292 *
293 * - discard preallocations in group:
294 * mark PAs deleted
295 * move them onto local list
296 * load on-disk bitmap
297 * load group
298 * remove PA from object (inode or locality group)
299 * mark free blocks in-core
300 *
301 * - discard inode's preallocations:
302 */
303
304/*
305 * Locking rules
306 *
307 * Locks:
308 * - bitlock on a group (group)
309 * - object (inode/locality) (object)
310 * - per-pa lock (pa)
311 *
312 * Paths:
313 * - new pa
314 * object
315 * group
316 *
317 * - find and use pa:
318 * pa
319 *
320 * - release consumed pa:
321 * pa
322 * group
323 * object
324 *
325 * - generate in-core bitmap:
326 * group
327 * pa
328 *
329 * - discard all for given object (inode, locality group):
330 * object
331 * pa
332 * group
333 *
334 * - discard all for given group:
335 * group
336 * pa
337 * group
338 * object
339 *
340 */
341static struct kmem_cache *ext4_pspace_cachep;
342static struct kmem_cache *ext4_ac_cachep;
343static struct kmem_cache *ext4_free_data_cachep;
344
345/* We create slab caches for groupinfo data structures based on the
346 * superblock block size. There will be one per mounted filesystem for
347 * each unique s_blocksize_bits */
348#define NR_GRPINFO_CACHES 8
349static struct kmem_cache *ext4_groupinfo_caches[NR_GRPINFO_CACHES];
350
351static const char *ext4_groupinfo_slab_names[NR_GRPINFO_CACHES] = {
352 "ext4_groupinfo_1k", "ext4_groupinfo_2k", "ext4_groupinfo_4k",
353 "ext4_groupinfo_8k", "ext4_groupinfo_16k", "ext4_groupinfo_32k",
354 "ext4_groupinfo_64k", "ext4_groupinfo_128k"
355};
356
357static void ext4_mb_generate_from_pa(struct super_block *sb, void *bitmap,
358 ext4_group_t group);
359static void ext4_mb_generate_from_freelist(struct super_block *sb, void *bitmap,
360 ext4_group_t group);
361static void ext4_free_data_callback(struct super_block *sb,
362 struct ext4_journal_cb_entry *jce, int rc);
363
364static inline void *mb_correct_addr_and_bit(int *bit, void *addr)
365{
366#if BITS_PER_LONG == 64
367 *bit += ((unsigned long) addr & 7UL) << 3;
368 addr = (void *) ((unsigned long) addr & ~7UL);
369#elif BITS_PER_LONG == 32
370 *bit += ((unsigned long) addr & 3UL) << 3;
371 addr = (void *) ((unsigned long) addr & ~3UL);
372#else
373#error "how many bits you are?!"
374#endif
375 return addr;
376}
377
378static inline int mb_test_bit(int bit, void *addr)
379{
380 /*
381 * ext4_test_bit on architecture like powerpc
382 * needs unsigned long aligned address
383 */
384 addr = mb_correct_addr_and_bit(&bit, addr);
385 return ext4_test_bit(bit, addr);
386}
387
388static inline void mb_set_bit(int bit, void *addr)
389{
390 addr = mb_correct_addr_and_bit(&bit, addr);
391 ext4_set_bit(bit, addr);
392}
393
394static inline void mb_clear_bit(int bit, void *addr)
395{
396 addr = mb_correct_addr_and_bit(&bit, addr);
397 ext4_clear_bit(bit, addr);
398}
399
400static inline int mb_find_next_zero_bit(void *addr, int max, int start)
401{
402 int fix = 0, ret, tmpmax;
403 addr = mb_correct_addr_and_bit(&fix, addr);
404 tmpmax = max + fix;
405 start += fix;
406
407 ret = ext4_find_next_zero_bit(addr, tmpmax, start) - fix;
408 if (ret > max)
409 return max;
410 return ret;
411}
412
413static inline int mb_find_next_bit(void *addr, int max, int start)
414{
415 int fix = 0, ret, tmpmax;
416 addr = mb_correct_addr_and_bit(&fix, addr);
417 tmpmax = max + fix;
418 start += fix;
419
420 ret = ext4_find_next_bit(addr, tmpmax, start) - fix;
421 if (ret > max)
422 return max;
423 return ret;
424}
425
426static void *mb_find_buddy(struct ext4_buddy *e4b, int order, int *max)
427{
428 char *bb;
429
430 BUG_ON(e4b->bd_bitmap == e4b->bd_buddy);
431 BUG_ON(max == NULL);
432
433 if (order > e4b->bd_blkbits + 1) {
434 *max = 0;
435 return NULL;
436 }
437
438 /* at order 0 we see each particular block */
439 if (order == 0) {
440 *max = 1 << (e4b->bd_blkbits + 3);
441 return e4b->bd_bitmap;
442 }
443
444 bb = e4b->bd_buddy + EXT4_SB(e4b->bd_sb)->s_mb_offsets[order];
445 *max = EXT4_SB(e4b->bd_sb)->s_mb_maxs[order];
446
447 return bb;
448}
449
450#ifdef DOUBLE_CHECK
451static void mb_free_blocks_double(struct inode *inode, struct ext4_buddy *e4b,
452 int first, int count)
453{
454 int i;
455 struct super_block *sb = e4b->bd_sb;
456
457 if (unlikely(e4b->bd_info->bb_bitmap == NULL))
458 return;
459 assert_spin_locked(ext4_group_lock_ptr(sb, e4b->bd_group));
460 for (i = 0; i < count; i++) {
461 if (!mb_test_bit(first + i, e4b->bd_info->bb_bitmap)) {
462 ext4_fsblk_t blocknr;
463
464 blocknr = ext4_group_first_block_no(sb, e4b->bd_group);
465 blocknr += EXT4_C2B(EXT4_SB(sb), first + i);
466 ext4_grp_locked_error(sb, e4b->bd_group,
467 inode ? inode->i_ino : 0,
468 blocknr,
469 "freeing block already freed "
470 "(bit %u)",
471 first + i);
472 }
473 mb_clear_bit(first + i, e4b->bd_info->bb_bitmap);
474 }
475}
476
477static void mb_mark_used_double(struct ext4_buddy *e4b, int first, int count)
478{
479 int i;
480
481 if (unlikely(e4b->bd_info->bb_bitmap == NULL))
482 return;
483 assert_spin_locked(ext4_group_lock_ptr(e4b->bd_sb, e4b->bd_group));
484 for (i = 0; i < count; i++) {
485 BUG_ON(mb_test_bit(first + i, e4b->bd_info->bb_bitmap));
486 mb_set_bit(first + i, e4b->bd_info->bb_bitmap);
487 }
488}
489
490static void mb_cmp_bitmaps(struct ext4_buddy *e4b, void *bitmap)
491{
492 if (memcmp(e4b->bd_info->bb_bitmap, bitmap, e4b->bd_sb->s_blocksize)) {
493 unsigned char *b1, *b2;
494 int i;
495 b1 = (unsigned char *) e4b->bd_info->bb_bitmap;
496 b2 = (unsigned char *) bitmap;
497 for (i = 0; i < e4b->bd_sb->s_blocksize; i++) {
498 if (b1[i] != b2[i]) {
499 ext4_msg(e4b->bd_sb, KERN_ERR,
500 "corruption in group %u "
501 "at byte %u(%u): %x in copy != %x "
502 "on disk/prealloc",
503 e4b->bd_group, i, i * 8, b1[i], b2[i]);
504 BUG();
505 }
506 }
507 }
508}
509
510#else
511static inline void mb_free_blocks_double(struct inode *inode,
512 struct ext4_buddy *e4b, int first, int count)
513{
514 return;
515}
516static inline void mb_mark_used_double(struct ext4_buddy *e4b,
517 int first, int count)
518{
519 return;
520}
521static inline void mb_cmp_bitmaps(struct ext4_buddy *e4b, void *bitmap)
522{
523 return;
524}
525#endif
526
527#ifdef AGGRESSIVE_CHECK
528
529#define MB_CHECK_ASSERT(assert) \
530do { \
531 if (!(assert)) { \
532 printk(KERN_EMERG \
533 "Assertion failure in %s() at %s:%d: \"%s\"\n", \
534 function, file, line, # assert); \
535 BUG(); \
536 } \
537} while (0)
538
539static int __mb_check_buddy(struct ext4_buddy *e4b, char *file,
540 const char *function, int line)
541{
542 struct super_block *sb = e4b->bd_sb;
543 int order = e4b->bd_blkbits + 1;
544 int max;
545 int max2;
546 int i;
547 int j;
548 int k;
549 int count;
550 struct ext4_group_info *grp;
551 int fragments = 0;
552 int fstart;
553 struct list_head *cur;
554 void *buddy;
555 void *buddy2;
556
557 {
558 static int mb_check_counter;
559 if (mb_check_counter++ % 100 != 0)
560 return 0;
561 }
562
563 while (order > 1) {
564 buddy = mb_find_buddy(e4b, order, &max);
565 MB_CHECK_ASSERT(buddy);
566 buddy2 = mb_find_buddy(e4b, order - 1, &max2);
567 MB_CHECK_ASSERT(buddy2);
568 MB_CHECK_ASSERT(buddy != buddy2);
569 MB_CHECK_ASSERT(max * 2 == max2);
570
571 count = 0;
572 for (i = 0; i < max; i++) {
573
574 if (mb_test_bit(i, buddy)) {
575 /* only single bit in buddy2 may be 1 */
576 if (!mb_test_bit(i << 1, buddy2)) {
577 MB_CHECK_ASSERT(
578 mb_test_bit((i<<1)+1, buddy2));
579 } else if (!mb_test_bit((i << 1) + 1, buddy2)) {
580 MB_CHECK_ASSERT(
581 mb_test_bit(i << 1, buddy2));
582 }
583 continue;
584 }
585
586 /* both bits in buddy2 must be 1 */
587 MB_CHECK_ASSERT(mb_test_bit(i << 1, buddy2));
588 MB_CHECK_ASSERT(mb_test_bit((i << 1) + 1, buddy2));
589
590 for (j = 0; j < (1 << order); j++) {
591 k = (i * (1 << order)) + j;
592 MB_CHECK_ASSERT(
593 !mb_test_bit(k, e4b->bd_bitmap));
594 }
595 count++;
596 }
597 MB_CHECK_ASSERT(e4b->bd_info->bb_counters[order] == count);
598 order--;
599 }
600
601 fstart = -1;
602 buddy = mb_find_buddy(e4b, 0, &max);
603 for (i = 0; i < max; i++) {
604 if (!mb_test_bit(i, buddy)) {
605 MB_CHECK_ASSERT(i >= e4b->bd_info->bb_first_free);
606 if (fstart == -1) {
607 fragments++;
608 fstart = i;
609 }
610 continue;
611 }
612 fstart = -1;
613 /* check used bits only */
614 for (j = 0; j < e4b->bd_blkbits + 1; j++) {
615 buddy2 = mb_find_buddy(e4b, j, &max2);
616 k = i >> j;
617 MB_CHECK_ASSERT(k < max2);
618 MB_CHECK_ASSERT(mb_test_bit(k, buddy2));
619 }
620 }
621 MB_CHECK_ASSERT(!EXT4_MB_GRP_NEED_INIT(e4b->bd_info));
622 MB_CHECK_ASSERT(e4b->bd_info->bb_fragments == fragments);
623
624 grp = ext4_get_group_info(sb, e4b->bd_group);
625 list_for_each(cur, &grp->bb_prealloc_list) {
626 ext4_group_t groupnr;
627 struct ext4_prealloc_space *pa;
628 pa = list_entry(cur, struct ext4_prealloc_space, pa_group_list);
629 ext4_get_group_no_and_offset(sb, pa->pa_pstart, &groupnr, &k);
630 MB_CHECK_ASSERT(groupnr == e4b->bd_group);
631 for (i = 0; i < pa->pa_len; i++)
632 MB_CHECK_ASSERT(mb_test_bit(k + i, buddy));
633 }
634 return 0;
635}
636#undef MB_CHECK_ASSERT
637#define mb_check_buddy(e4b) __mb_check_buddy(e4b, \
638 __FILE__, __func__, __LINE__)
639#else
640#define mb_check_buddy(e4b)
641#endif
642
643/*
644 * Divide blocks started from @first with length @len into
645 * smaller chunks with power of 2 blocks.
646 * Clear the bits in bitmap which the blocks of the chunk(s) covered,
647 * then increase bb_counters[] for corresponded chunk size.
648 */
649static void ext4_mb_mark_free_simple(struct super_block *sb,
650 void *buddy, ext4_grpblk_t first, ext4_grpblk_t len,
651 struct ext4_group_info *grp)
652{
653 struct ext4_sb_info *sbi = EXT4_SB(sb);
654 ext4_grpblk_t min;
655 ext4_grpblk_t max;
656 ext4_grpblk_t chunk;
657 unsigned short border;
658
659 BUG_ON(len > EXT4_CLUSTERS_PER_GROUP(sb));
660
661 border = 2 << sb->s_blocksize_bits;
662
663 while (len > 0) {
664 /* find how many blocks can be covered since this position */
665 max = ffs(first | border) - 1;
666
667 /* find how many blocks of power 2 we need to mark */
668 min = fls(len) - 1;
669
670 if (max < min)
671 min = max;
672 chunk = 1 << min;
673
674 /* mark multiblock chunks only */
675 grp->bb_counters[min]++;
676 if (min > 0)
677 mb_clear_bit(first >> min,
678 buddy + sbi->s_mb_offsets[min]);
679
680 len -= chunk;
681 first += chunk;
682 }
683}
684
685/*
686 * Cache the order of the largest free extent we have available in this block
687 * group.
688 */
689static void
690mb_set_largest_free_order(struct super_block *sb, struct ext4_group_info *grp)
691{
692 int i;
693 int bits;
694
695 grp->bb_largest_free_order = -1; /* uninit */
696
697 bits = sb->s_blocksize_bits + 1;
698 for (i = bits; i >= 0; i--) {
699 if (grp->bb_counters[i] > 0) {
700 grp->bb_largest_free_order = i;
701 break;
702 }
703 }
704}
705
706static noinline_for_stack
707void ext4_mb_generate_buddy(struct super_block *sb,
708 void *buddy, void *bitmap, ext4_group_t group)
709{
710 struct ext4_group_info *grp = ext4_get_group_info(sb, group);
711 ext4_grpblk_t max = EXT4_CLUSTERS_PER_GROUP(sb);
712 ext4_grpblk_t i = 0;
713 ext4_grpblk_t first;
714 ext4_grpblk_t len;
715 unsigned free = 0;
716 unsigned fragments = 0;
717 unsigned long long period = get_cycles();
718
719 /* initialize buddy from bitmap which is aggregation
720 * of on-disk bitmap and preallocations */
721 i = mb_find_next_zero_bit(bitmap, max, 0);
722 grp->bb_first_free = i;
723 while (i < max) {
724 fragments++;
725 first = i;
726 i = mb_find_next_bit(bitmap, max, i);
727 len = i - first;
728 free += len;
729 if (len > 1)
730 ext4_mb_mark_free_simple(sb, buddy, first, len, grp);
731 else
732 grp->bb_counters[0]++;
733 if (i < max)
734 i = mb_find_next_zero_bit(bitmap, max, i);
735 }
736 grp->bb_fragments = fragments;
737
738 if (free != grp->bb_free) {
739 ext4_grp_locked_error(sb, group, 0, 0,
740 "%u clusters in bitmap, %u in gd",
741 free, grp->bb_free);
742 /*
743 * If we intent to continue, we consider group descritor
744 * corrupt and update bb_free using bitmap value
745 */
746 grp->bb_free = free;
747 }
748 mb_set_largest_free_order(sb, grp);
749
750 clear_bit(EXT4_GROUP_INFO_NEED_INIT_BIT, &(grp->bb_state));
751
752 period = get_cycles() - period;
753 spin_lock(&EXT4_SB(sb)->s_bal_lock);
754 EXT4_SB(sb)->s_mb_buddies_generated++;
755 EXT4_SB(sb)->s_mb_generation_time += period;
756 spin_unlock(&EXT4_SB(sb)->s_bal_lock);
757}
758
759/* The buddy information is attached the buddy cache inode
760 * for convenience. The information regarding each group
761 * is loaded via ext4_mb_load_buddy. The information involve
762 * block bitmap and buddy information. The information are
763 * stored in the inode as
764 *
765 * { page }
766 * [ group 0 bitmap][ group 0 buddy] [group 1][ group 1]...
767 *
768 *
769 * one block each for bitmap and buddy information.
770 * So for each group we take up 2 blocks. A page can
771 * contain blocks_per_page (PAGE_CACHE_SIZE / blocksize) blocks.
772 * So it can have information regarding groups_per_page which
773 * is blocks_per_page/2
774 *
775 * Locking note: This routine takes the block group lock of all groups
776 * for this page; do not hold this lock when calling this routine!
777 */
778
779static int ext4_mb_init_cache(struct page *page, char *incore)
780{
781 ext4_group_t ngroups;
782 int blocksize;
783 int blocks_per_page;
784 int groups_per_page;
785 int err = 0;
786 int i;
787 ext4_group_t first_group, group;
788 int first_block;
789 struct super_block *sb;
790 struct buffer_head *bhs;
791 struct buffer_head **bh = NULL;
792 struct inode *inode;
793 char *data;
794 char *bitmap;
795 struct ext4_group_info *grinfo;
796
797 mb_debug(1, "init page %lu\n", page->index);
798
799 inode = page->mapping->host;
800 sb = inode->i_sb;
801 ngroups = ext4_get_groups_count(sb);
802 blocksize = 1 << inode->i_blkbits;
803 blocks_per_page = PAGE_CACHE_SIZE / blocksize;
804
805 groups_per_page = blocks_per_page >> 1;
806 if (groups_per_page == 0)
807 groups_per_page = 1;
808
809 /* allocate buffer_heads to read bitmaps */
810 if (groups_per_page > 1) {
811 i = sizeof(struct buffer_head *) * groups_per_page;
812 bh = kzalloc(i, GFP_NOFS);
813 if (bh == NULL) {
814 err = -ENOMEM;
815 goto out;
816 }
817 } else
818 bh = &bhs;
819
820 first_group = page->index * blocks_per_page / 2;
821
822 /* read all groups the page covers into the cache */
823 for (i = 0, group = first_group; i < groups_per_page; i++, group++) {
824 if (group >= ngroups)
825 break;
826
827 grinfo = ext4_get_group_info(sb, group);
828 /*
829 * If page is uptodate then we came here after online resize
830 * which added some new uninitialized group info structs, so
831 * we must skip all initialized uptodate buddies on the page,
832 * which may be currently in use by an allocating task.
833 */
834 if (PageUptodate(page) && !EXT4_MB_GRP_NEED_INIT(grinfo)) {
835 bh[i] = NULL;
836 continue;
837 }
838 if (!(bh[i] = ext4_read_block_bitmap_nowait(sb, group))) {
839 err = -ENOMEM;
840 goto out;
841 }
842 mb_debug(1, "read bitmap for group %u\n", group);
843 }
844
845 /* wait for I/O completion */
846 for (i = 0, group = first_group; i < groups_per_page; i++, group++) {
847 if (bh[i] && ext4_wait_block_bitmap(sb, group, bh[i])) {
848 err = -EIO;
849 goto out;
850 }
851 }
852
853 first_block = page->index * blocks_per_page;
854 for (i = 0; i < blocks_per_page; i++) {
855 int group;
856
857 group = (first_block + i) >> 1;
858 if (group >= ngroups)
859 break;
860
861 if (!bh[group - first_group])
862 /* skip initialized uptodate buddy */
863 continue;
864
865 /*
866 * data carry information regarding this
867 * particular group in the format specified
868 * above
869 *
870 */
871 data = page_address(page) + (i * blocksize);
872 bitmap = bh[group - first_group]->b_data;
873
874 /*
875 * We place the buddy block and bitmap block
876 * close together
877 */
878 if ((first_block + i) & 1) {
879 /* this is block of buddy */
880 BUG_ON(incore == NULL);
881 mb_debug(1, "put buddy for group %u in page %lu/%x\n",
882 group, page->index, i * blocksize);
883 trace_ext4_mb_buddy_bitmap_load(sb, group);
884 grinfo = ext4_get_group_info(sb, group);
885 grinfo->bb_fragments = 0;
886 memset(grinfo->bb_counters, 0,
887 sizeof(*grinfo->bb_counters) *
888 (sb->s_blocksize_bits+2));
889 /*
890 * incore got set to the group block bitmap below
891 */
892 ext4_lock_group(sb, group);
893 /* init the buddy */
894 memset(data, 0xff, blocksize);
895 ext4_mb_generate_buddy(sb, data, incore, group);
896 ext4_unlock_group(sb, group);
897 incore = NULL;
898 } else {
899 /* this is block of bitmap */
900 BUG_ON(incore != NULL);
901 mb_debug(1, "put bitmap for group %u in page %lu/%x\n",
902 group, page->index, i * blocksize);
903 trace_ext4_mb_bitmap_load(sb, group);
904
905 /* see comments in ext4_mb_put_pa() */
906 ext4_lock_group(sb, group);
907 memcpy(data, bitmap, blocksize);
908
909 /* mark all preallocated blks used in in-core bitmap */
910 ext4_mb_generate_from_pa(sb, data, group);
911 ext4_mb_generate_from_freelist(sb, data, group);
912 ext4_unlock_group(sb, group);
913
914 /* set incore so that the buddy information can be
915 * generated using this
916 */
917 incore = data;
918 }
919 }
920 SetPageUptodate(page);
921
922out:
923 if (bh) {
924 for (i = 0; i < groups_per_page; i++)
925 brelse(bh[i]);
926 if (bh != &bhs)
927 kfree(bh);
928 }
929 return err;
930}
931
932/*
933 * Lock the buddy and bitmap pages. This make sure other parallel init_group
934 * on the same buddy page doesn't happen whild holding the buddy page lock.
935 * Return locked buddy and bitmap pages on e4b struct. If buddy and bitmap
936 * are on the same page e4b->bd_buddy_page is NULL and return value is 0.
937 */
938static int ext4_mb_get_buddy_page_lock(struct super_block *sb,
939 ext4_group_t group, struct ext4_buddy *e4b)
940{
941 struct inode *inode = EXT4_SB(sb)->s_buddy_cache;
942 int block, pnum, poff;
943 int blocks_per_page;
944 struct page *page;
945
946 e4b->bd_buddy_page = NULL;
947 e4b->bd_bitmap_page = NULL;
948
949 blocks_per_page = PAGE_CACHE_SIZE / sb->s_blocksize;
950 /*
951 * the buddy cache inode stores the block bitmap
952 * and buddy information in consecutive blocks.
953 * So for each group we need two blocks.
954 */
955 block = group * 2;
956 pnum = block / blocks_per_page;
957 poff = block % blocks_per_page;
958 page = find_or_create_page(inode->i_mapping, pnum, GFP_NOFS);
959 if (!page)
960 return -EIO;
961 BUG_ON(page->mapping != inode->i_mapping);
962 e4b->bd_bitmap_page = page;
963 e4b->bd_bitmap = page_address(page) + (poff * sb->s_blocksize);
964
965 if (blocks_per_page >= 2) {
966 /* buddy and bitmap are on the same page */
967 return 0;
968 }
969
970 block++;
971 pnum = block / blocks_per_page;
972 poff = block % blocks_per_page;
973 page = find_or_create_page(inode->i_mapping, pnum, GFP_NOFS);
974 if (!page)
975 return -EIO;
976 BUG_ON(page->mapping != inode->i_mapping);
977 e4b->bd_buddy_page = page;
978 return 0;
979}
980
981static void ext4_mb_put_buddy_page_lock(struct ext4_buddy *e4b)
982{
983 if (e4b->bd_bitmap_page) {
984 unlock_page(e4b->bd_bitmap_page);
985 page_cache_release(e4b->bd_bitmap_page);
986 }
987 if (e4b->bd_buddy_page) {
988 unlock_page(e4b->bd_buddy_page);
989 page_cache_release(e4b->bd_buddy_page);
990 }
991}
992
993/*
994 * Locking note: This routine calls ext4_mb_init_cache(), which takes the
995 * block group lock of all groups for this page; do not hold the BG lock when
996 * calling this routine!
997 */
998static noinline_for_stack
999int ext4_mb_init_group(struct super_block *sb, ext4_group_t group)
1000{
1001
1002 struct ext4_group_info *this_grp;
1003 struct ext4_buddy e4b;
1004 struct page *page;
1005 int ret = 0;
1006
1007 mb_debug(1, "init group %u\n", group);
1008 this_grp = ext4_get_group_info(sb, group);
1009 /*
1010 * This ensures that we don't reinit the buddy cache
1011 * page which map to the group from which we are already
1012 * allocating. If we are looking at the buddy cache we would
1013 * have taken a reference using ext4_mb_load_buddy and that
1014 * would have pinned buddy page to page cache.
1015 */
1016 ret = ext4_mb_get_buddy_page_lock(sb, group, &e4b);
1017 if (ret || !EXT4_MB_GRP_NEED_INIT(this_grp)) {
1018 /*
1019 * somebody initialized the group
1020 * return without doing anything
1021 */
1022 goto err;
1023 }
1024
1025 page = e4b.bd_bitmap_page;
1026 ret = ext4_mb_init_cache(page, NULL);
1027 if (ret)
1028 goto err;
1029 if (!PageUptodate(page)) {
1030 ret = -EIO;
1031 goto err;
1032 }
1033 mark_page_accessed(page);
1034
1035 if (e4b.bd_buddy_page == NULL) {
1036 /*
1037 * If both the bitmap and buddy are in
1038 * the same page we don't need to force
1039 * init the buddy
1040 */
1041 ret = 0;
1042 goto err;
1043 }
1044 /* init buddy cache */
1045 page = e4b.bd_buddy_page;
1046 ret = ext4_mb_init_cache(page, e4b.bd_bitmap);
1047 if (ret)
1048 goto err;
1049 if (!PageUptodate(page)) {
1050 ret = -EIO;
1051 goto err;
1052 }
1053 mark_page_accessed(page);
1054err:
1055 ext4_mb_put_buddy_page_lock(&e4b);
1056 return ret;
1057}
1058
1059/*
1060 * Locking note: This routine calls ext4_mb_init_cache(), which takes the
1061 * block group lock of all groups for this page; do not hold the BG lock when
1062 * calling this routine!
1063 */
1064static noinline_for_stack int
1065ext4_mb_load_buddy(struct super_block *sb, ext4_group_t group,
1066 struct ext4_buddy *e4b)
1067{
1068 int blocks_per_page;
1069 int block;
1070 int pnum;
1071 int poff;
1072 struct page *page;
1073 int ret;
1074 struct ext4_group_info *grp;
1075 struct ext4_sb_info *sbi = EXT4_SB(sb);
1076 struct inode *inode = sbi->s_buddy_cache;
1077
1078 mb_debug(1, "load group %u\n", group);
1079
1080 blocks_per_page = PAGE_CACHE_SIZE / sb->s_blocksize;
1081 grp = ext4_get_group_info(sb, group);
1082
1083 e4b->bd_blkbits = sb->s_blocksize_bits;
1084 e4b->bd_info = grp;
1085 e4b->bd_sb = sb;
1086 e4b->bd_group = group;
1087 e4b->bd_buddy_page = NULL;
1088 e4b->bd_bitmap_page = NULL;
1089
1090 if (unlikely(EXT4_MB_GRP_NEED_INIT(grp))) {
1091 /*
1092 * we need full data about the group
1093 * to make a good selection
1094 */
1095 ret = ext4_mb_init_group(sb, group);
1096 if (ret)
1097 return ret;
1098 }
1099
1100 /*
1101 * the buddy cache inode stores the block bitmap
1102 * and buddy information in consecutive blocks.
1103 * So for each group we need two blocks.
1104 */
1105 block = group * 2;
1106 pnum = block / blocks_per_page;
1107 poff = block % blocks_per_page;
1108
1109 /* we could use find_or_create_page(), but it locks page
1110 * what we'd like to avoid in fast path ... */
1111 page = find_get_page(inode->i_mapping, pnum);
1112 if (page == NULL || !PageUptodate(page)) {
1113 if (page)
1114 /*
1115 * drop the page reference and try
1116 * to get the page with lock. If we
1117 * are not uptodate that implies
1118 * somebody just created the page but
1119 * is yet to initialize the same. So
1120 * wait for it to initialize.
1121 */
1122 page_cache_release(page);
1123 page = find_or_create_page(inode->i_mapping, pnum, GFP_NOFS);
1124 if (page) {
1125 BUG_ON(page->mapping != inode->i_mapping);
1126 if (!PageUptodate(page)) {
1127 ret = ext4_mb_init_cache(page, NULL);
1128 if (ret) {
1129 unlock_page(page);
1130 goto err;
1131 }
1132 mb_cmp_bitmaps(e4b, page_address(page) +
1133 (poff * sb->s_blocksize));
1134 }
1135 unlock_page(page);
1136 }
1137 }
1138 if (page == NULL || !PageUptodate(page)) {
1139 ret = -EIO;
1140 goto err;
1141 }
1142 e4b->bd_bitmap_page = page;
1143 e4b->bd_bitmap = page_address(page) + (poff * sb->s_blocksize);
1144 mark_page_accessed(page);
1145
1146 block++;
1147 pnum = block / blocks_per_page;
1148 poff = block % blocks_per_page;
1149
1150 page = find_get_page(inode->i_mapping, pnum);
1151 if (page == NULL || !PageUptodate(page)) {
1152 if (page)
1153 page_cache_release(page);
1154 page = find_or_create_page(inode->i_mapping, pnum, GFP_NOFS);
1155 if (page) {
1156 BUG_ON(page->mapping != inode->i_mapping);
1157 if (!PageUptodate(page)) {
1158 ret = ext4_mb_init_cache(page, e4b->bd_bitmap);
1159 if (ret) {
1160 unlock_page(page);
1161 goto err;
1162 }
1163 }
1164 unlock_page(page);
1165 }
1166 }
1167 if (page == NULL || !PageUptodate(page)) {
1168 ret = -EIO;
1169 goto err;
1170 }
1171 e4b->bd_buddy_page = page;
1172 e4b->bd_buddy = page_address(page) + (poff * sb->s_blocksize);
1173 mark_page_accessed(page);
1174
1175 BUG_ON(e4b->bd_bitmap_page == NULL);
1176 BUG_ON(e4b->bd_buddy_page == NULL);
1177
1178 return 0;
1179
1180err:
1181 if (page)
1182 page_cache_release(page);
1183 if (e4b->bd_bitmap_page)
1184 page_cache_release(e4b->bd_bitmap_page);
1185 if (e4b->bd_buddy_page)
1186 page_cache_release(e4b->bd_buddy_page);
1187 e4b->bd_buddy = NULL;
1188 e4b->bd_bitmap = NULL;
1189 return ret;
1190}
1191
1192static void ext4_mb_unload_buddy(struct ext4_buddy *e4b)
1193{
1194 if (e4b->bd_bitmap_page)
1195 page_cache_release(e4b->bd_bitmap_page);
1196 if (e4b->bd_buddy_page)
1197 page_cache_release(e4b->bd_buddy_page);
1198}
1199
1200
1201static int mb_find_order_for_block(struct ext4_buddy *e4b, int block)
1202{
1203 int order = 1;
1204 void *bb;
1205
1206 BUG_ON(e4b->bd_bitmap == e4b->bd_buddy);
1207 BUG_ON(block >= (1 << (e4b->bd_blkbits + 3)));
1208
1209 bb = e4b->bd_buddy;
1210 while (order <= e4b->bd_blkbits + 1) {
1211 block = block >> 1;
1212 if (!mb_test_bit(block, bb)) {
1213 /* this block is part of buddy of order 'order' */
1214 return order;
1215 }
1216 bb += 1 << (e4b->bd_blkbits - order);
1217 order++;
1218 }
1219 return 0;
1220}
1221
1222static void mb_clear_bits(void *bm, int cur, int len)
1223{
1224 __u32 *addr;
1225
1226 len = cur + len;
1227 while (cur < len) {
1228 if ((cur & 31) == 0 && (len - cur) >= 32) {
1229 /* fast path: clear whole word at once */
1230 addr = bm + (cur >> 3);
1231 *addr = 0;
1232 cur += 32;
1233 continue;
1234 }
1235 mb_clear_bit(cur, bm);
1236 cur++;
1237 }
1238}
1239
1240void ext4_set_bits(void *bm, int cur, int len)
1241{
1242 __u32 *addr;
1243
1244 len = cur + len;
1245 while (cur < len) {
1246 if ((cur & 31) == 0 && (len - cur) >= 32) {
1247 /* fast path: set whole word at once */
1248 addr = bm + (cur >> 3);
1249 *addr = 0xffffffff;
1250 cur += 32;
1251 continue;
1252 }
1253 mb_set_bit(cur, bm);
1254 cur++;
1255 }
1256}
1257
1258static void mb_free_blocks(struct inode *inode, struct ext4_buddy *e4b,
1259 int first, int count)
1260{
1261 int block = 0;
1262 int max = 0;
1263 int order;
1264 void *buddy;
1265 void *buddy2;
1266 struct super_block *sb = e4b->bd_sb;
1267
1268 BUG_ON(first + count > (sb->s_blocksize << 3));
1269 assert_spin_locked(ext4_group_lock_ptr(sb, e4b->bd_group));
1270 mb_check_buddy(e4b);
1271 mb_free_blocks_double(inode, e4b, first, count);
1272
1273 e4b->bd_info->bb_free += count;
1274 if (first < e4b->bd_info->bb_first_free)
1275 e4b->bd_info->bb_first_free = first;
1276
1277 /* let's maintain fragments counter */
1278 if (first != 0)
1279 block = !mb_test_bit(first - 1, e4b->bd_bitmap);
1280 if (first + count < EXT4_SB(sb)->s_mb_maxs[0])
1281 max = !mb_test_bit(first + count, e4b->bd_bitmap);
1282 if (block && max)
1283 e4b->bd_info->bb_fragments--;
1284 else if (!block && !max)
1285 e4b->bd_info->bb_fragments++;
1286
1287 /* let's maintain buddy itself */
1288 while (count-- > 0) {
1289 block = first++;
1290 order = 0;
1291
1292 if (!mb_test_bit(block, e4b->bd_bitmap)) {
1293 ext4_fsblk_t blocknr;
1294
1295 blocknr = ext4_group_first_block_no(sb, e4b->bd_group);
1296 blocknr += EXT4_C2B(EXT4_SB(sb), block);
1297 ext4_grp_locked_error(sb, e4b->bd_group,
1298 inode ? inode->i_ino : 0,
1299 blocknr,
1300 "freeing already freed block "
1301 "(bit %u)", block);
1302 }
1303 mb_clear_bit(block, e4b->bd_bitmap);
1304 e4b->bd_info->bb_counters[order]++;
1305
1306 /* start of the buddy */
1307 buddy = mb_find_buddy(e4b, order, &max);
1308
1309 do {
1310 block &= ~1UL;
1311 if (mb_test_bit(block, buddy) ||
1312 mb_test_bit(block + 1, buddy))
1313 break;
1314
1315 /* both the buddies are free, try to coalesce them */
1316 buddy2 = mb_find_buddy(e4b, order + 1, &max);
1317
1318 if (!buddy2)
1319 break;
1320
1321 if (order > 0) {
1322 /* for special purposes, we don't set
1323 * free bits in bitmap */
1324 mb_set_bit(block, buddy);
1325 mb_set_bit(block + 1, buddy);
1326 }
1327 e4b->bd_info->bb_counters[order]--;
1328 e4b->bd_info->bb_counters[order]--;
1329
1330 block = block >> 1;
1331 order++;
1332 e4b->bd_info->bb_counters[order]++;
1333
1334 mb_clear_bit(block, buddy2);
1335 buddy = buddy2;
1336 } while (1);
1337 }
1338 mb_set_largest_free_order(sb, e4b->bd_info);
1339 mb_check_buddy(e4b);
1340}
1341
1342static int mb_find_extent(struct ext4_buddy *e4b, int order, int block,
1343 int needed, struct ext4_free_extent *ex)
1344{
1345 int next = block;
1346 int max;
1347 void *buddy;
1348
1349 assert_spin_locked(ext4_group_lock_ptr(e4b->bd_sb, e4b->bd_group));
1350 BUG_ON(ex == NULL);
1351
1352 buddy = mb_find_buddy(e4b, order, &max);
1353 BUG_ON(buddy == NULL);
1354 BUG_ON(block >= max);
1355 if (mb_test_bit(block, buddy)) {
1356 ex->fe_len = 0;
1357 ex->fe_start = 0;
1358 ex->fe_group = 0;
1359 return 0;
1360 }
1361
1362 /* FIXME dorp order completely ? */
1363 if (likely(order == 0)) {
1364 /* find actual order */
1365 order = mb_find_order_for_block(e4b, block);
1366 block = block >> order;
1367 }
1368
1369 ex->fe_len = 1 << order;
1370 ex->fe_start = block << order;
1371 ex->fe_group = e4b->bd_group;
1372
1373 /* calc difference from given start */
1374 next = next - ex->fe_start;
1375 ex->fe_len -= next;
1376 ex->fe_start += next;
1377
1378 while (needed > ex->fe_len &&
1379 (buddy = mb_find_buddy(e4b, order, &max))) {
1380
1381 if (block + 1 >= max)
1382 break;
1383
1384 next = (block + 1) * (1 << order);
1385 if (mb_test_bit(next, e4b->bd_bitmap))
1386 break;
1387
1388 order = mb_find_order_for_block(e4b, next);
1389
1390 block = next >> order;
1391 ex->fe_len += 1 << order;
1392 }
1393
1394 BUG_ON(ex->fe_start + ex->fe_len > (1 << (e4b->bd_blkbits + 3)));
1395 return ex->fe_len;
1396}
1397
1398static int mb_mark_used(struct ext4_buddy *e4b, struct ext4_free_extent *ex)
1399{
1400 int ord;
1401 int mlen = 0;
1402 int max = 0;
1403 int cur;
1404 int start = ex->fe_start;
1405 int len = ex->fe_len;
1406 unsigned ret = 0;
1407 int len0 = len;
1408 void *buddy;
1409
1410 BUG_ON(start + len > (e4b->bd_sb->s_blocksize << 3));
1411 BUG_ON(e4b->bd_group != ex->fe_group);
1412 assert_spin_locked(ext4_group_lock_ptr(e4b->bd_sb, e4b->bd_group));
1413 mb_check_buddy(e4b);
1414 mb_mark_used_double(e4b, start, len);
1415
1416 e4b->bd_info->bb_free -= len;
1417 if (e4b->bd_info->bb_first_free == start)
1418 e4b->bd_info->bb_first_free += len;
1419
1420 /* let's maintain fragments counter */
1421 if (start != 0)
1422 mlen = !mb_test_bit(start - 1, e4b->bd_bitmap);
1423 if (start + len < EXT4_SB(e4b->bd_sb)->s_mb_maxs[0])
1424 max = !mb_test_bit(start + len, e4b->bd_bitmap);
1425 if (mlen && max)
1426 e4b->bd_info->bb_fragments++;
1427 else if (!mlen && !max)
1428 e4b->bd_info->bb_fragments--;
1429
1430 /* let's maintain buddy itself */
1431 while (len) {
1432 ord = mb_find_order_for_block(e4b, start);
1433
1434 if (((start >> ord) << ord) == start && len >= (1 << ord)) {
1435 /* the whole chunk may be allocated at once! */
1436 mlen = 1 << ord;
1437 buddy = mb_find_buddy(e4b, ord, &max);
1438 BUG_ON((start >> ord) >= max);
1439 mb_set_bit(start >> ord, buddy);
1440 e4b->bd_info->bb_counters[ord]--;
1441 start += mlen;
1442 len -= mlen;
1443 BUG_ON(len < 0);
1444 continue;
1445 }
1446
1447 /* store for history */
1448 if (ret == 0)
1449 ret = len | (ord << 16);
1450
1451 /* we have to split large buddy */
1452 BUG_ON(ord <= 0);
1453 buddy = mb_find_buddy(e4b, ord, &max);
1454 mb_set_bit(start >> ord, buddy);
1455 e4b->bd_info->bb_counters[ord]--;
1456
1457 ord--;
1458 cur = (start >> ord) & ~1U;
1459 buddy = mb_find_buddy(e4b, ord, &max);
1460 mb_clear_bit(cur, buddy);
1461 mb_clear_bit(cur + 1, buddy);
1462 e4b->bd_info->bb_counters[ord]++;
1463 e4b->bd_info->bb_counters[ord]++;
1464 }
1465 mb_set_largest_free_order(e4b->bd_sb, e4b->bd_info);
1466
1467 ext4_set_bits(e4b->bd_bitmap, ex->fe_start, len0);
1468 mb_check_buddy(e4b);
1469
1470 return ret;
1471}
1472
1473/*
1474 * Must be called under group lock!
1475 */
1476static void ext4_mb_use_best_found(struct ext4_allocation_context *ac,
1477 struct ext4_buddy *e4b)
1478{
1479 struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
1480 int ret;
1481
1482 BUG_ON(ac->ac_b_ex.fe_group != e4b->bd_group);
1483 BUG_ON(ac->ac_status == AC_STATUS_FOUND);
1484
1485 ac->ac_b_ex.fe_len = min(ac->ac_b_ex.fe_len, ac->ac_g_ex.fe_len);
1486 ac->ac_b_ex.fe_logical = ac->ac_g_ex.fe_logical;
1487 ret = mb_mark_used(e4b, &ac->ac_b_ex);
1488
1489 /* preallocation can change ac_b_ex, thus we store actually
1490 * allocated blocks for history */
1491 ac->ac_f_ex = ac->ac_b_ex;
1492
1493 ac->ac_status = AC_STATUS_FOUND;
1494 ac->ac_tail = ret & 0xffff;
1495 ac->ac_buddy = ret >> 16;
1496
1497 /*
1498 * take the page reference. We want the page to be pinned
1499 * so that we don't get a ext4_mb_init_cache_call for this
1500 * group until we update the bitmap. That would mean we
1501 * double allocate blocks. The reference is dropped
1502 * in ext4_mb_release_context
1503 */
1504 ac->ac_bitmap_page = e4b->bd_bitmap_page;
1505 get_page(ac->ac_bitmap_page);
1506 ac->ac_buddy_page = e4b->bd_buddy_page;
1507 get_page(ac->ac_buddy_page);
1508 /* store last allocated for subsequent stream allocation */
1509 if (ac->ac_flags & EXT4_MB_STREAM_ALLOC) {
1510 spin_lock(&sbi->s_md_lock);
1511 sbi->s_mb_last_group = ac->ac_f_ex.fe_group;
1512 sbi->s_mb_last_start = ac->ac_f_ex.fe_start;
1513 spin_unlock(&sbi->s_md_lock);
1514 }
1515}
1516
1517/*
1518 * regular allocator, for general purposes allocation
1519 */
1520
1521static void ext4_mb_check_limits(struct ext4_allocation_context *ac,
1522 struct ext4_buddy *e4b,
1523 int finish_group)
1524{
1525 struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
1526 struct ext4_free_extent *bex = &ac->ac_b_ex;
1527 struct ext4_free_extent *gex = &ac->ac_g_ex;
1528 struct ext4_free_extent ex;
1529 int max;
1530
1531 if (ac->ac_status == AC_STATUS_FOUND)
1532 return;
1533 /*
1534 * We don't want to scan for a whole year
1535 */
1536 if (ac->ac_found > sbi->s_mb_max_to_scan &&
1537 !(ac->ac_flags & EXT4_MB_HINT_FIRST)) {
1538 ac->ac_status = AC_STATUS_BREAK;
1539 return;
1540 }
1541
1542 /*
1543 * Haven't found good chunk so far, let's continue
1544 */
1545 if (bex->fe_len < gex->fe_len)
1546 return;
1547
1548 if ((finish_group || ac->ac_found > sbi->s_mb_min_to_scan)
1549 && bex->fe_group == e4b->bd_group) {
1550 /* recheck chunk's availability - we don't know
1551 * when it was found (within this lock-unlock
1552 * period or not) */
1553 max = mb_find_extent(e4b, 0, bex->fe_start, gex->fe_len, &ex);
1554 if (max >= gex->fe_len) {
1555 ext4_mb_use_best_found(ac, e4b);
1556 return;
1557 }
1558 }
1559}
1560
1561/*
1562 * The routine checks whether found extent is good enough. If it is,
1563 * then the extent gets marked used and flag is set to the context
1564 * to stop scanning. Otherwise, the extent is compared with the
1565 * previous found extent and if new one is better, then it's stored
1566 * in the context. Later, the best found extent will be used, if
1567 * mballoc can't find good enough extent.
1568 *
1569 * FIXME: real allocation policy is to be designed yet!
1570 */
1571static void ext4_mb_measure_extent(struct ext4_allocation_context *ac,
1572 struct ext4_free_extent *ex,
1573 struct ext4_buddy *e4b)
1574{
1575 struct ext4_free_extent *bex = &ac->ac_b_ex;
1576 struct ext4_free_extent *gex = &ac->ac_g_ex;
1577
1578 BUG_ON(ex->fe_len <= 0);
1579 BUG_ON(ex->fe_len > EXT4_CLUSTERS_PER_GROUP(ac->ac_sb));
1580 BUG_ON(ex->fe_start >= EXT4_CLUSTERS_PER_GROUP(ac->ac_sb));
1581 BUG_ON(ac->ac_status != AC_STATUS_CONTINUE);
1582
1583 ac->ac_found++;
1584
1585 /*
1586 * The special case - take what you catch first
1587 */
1588 if (unlikely(ac->ac_flags & EXT4_MB_HINT_FIRST)) {
1589 *bex = *ex;
1590 ext4_mb_use_best_found(ac, e4b);
1591 return;
1592 }
1593
1594 /*
1595 * Let's check whether the chuck is good enough
1596 */
1597 if (ex->fe_len == gex->fe_len) {
1598 *bex = *ex;
1599 ext4_mb_use_best_found(ac, e4b);
1600 return;
1601 }
1602
1603 /*
1604 * If this is first found extent, just store it in the context
1605 */
1606 if (bex->fe_len == 0) {
1607 *bex = *ex;
1608 return;
1609 }
1610
1611 /*
1612 * If new found extent is better, store it in the context
1613 */
1614 if (bex->fe_len < gex->fe_len) {
1615 /* if the request isn't satisfied, any found extent
1616 * larger than previous best one is better */
1617 if (ex->fe_len > bex->fe_len)
1618 *bex = *ex;
1619 } else if (ex->fe_len > gex->fe_len) {
1620 /* if the request is satisfied, then we try to find
1621 * an extent that still satisfy the request, but is
1622 * smaller than previous one */
1623 if (ex->fe_len < bex->fe_len)
1624 *bex = *ex;
1625 }
1626
1627 ext4_mb_check_limits(ac, e4b, 0);
1628}
1629
1630static noinline_for_stack
1631int ext4_mb_try_best_found(struct ext4_allocation_context *ac,
1632 struct ext4_buddy *e4b)
1633{
1634 struct ext4_free_extent ex = ac->ac_b_ex;
1635 ext4_group_t group = ex.fe_group;
1636 int max;
1637 int err;
1638
1639 BUG_ON(ex.fe_len <= 0);
1640 err = ext4_mb_load_buddy(ac->ac_sb, group, e4b);
1641 if (err)
1642 return err;
1643
1644 ext4_lock_group(ac->ac_sb, group);
1645 max = mb_find_extent(e4b, 0, ex.fe_start, ex.fe_len, &ex);
1646
1647 if (max > 0) {
1648 ac->ac_b_ex = ex;
1649 ext4_mb_use_best_found(ac, e4b);
1650 }
1651
1652 ext4_unlock_group(ac->ac_sb, group);
1653 ext4_mb_unload_buddy(e4b);
1654
1655 return 0;
1656}
1657
1658static noinline_for_stack
1659int ext4_mb_find_by_goal(struct ext4_allocation_context *ac,
1660 struct ext4_buddy *e4b)
1661{
1662 ext4_group_t group = ac->ac_g_ex.fe_group;
1663 int max;
1664 int err;
1665 struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
1666 struct ext4_free_extent ex;
1667
1668 if (!(ac->ac_flags & EXT4_MB_HINT_TRY_GOAL))
1669 return 0;
1670
1671 err = ext4_mb_load_buddy(ac->ac_sb, group, e4b);
1672 if (err)
1673 return err;
1674
1675 ext4_lock_group(ac->ac_sb, group);
1676 max = mb_find_extent(e4b, 0, ac->ac_g_ex.fe_start,
1677 ac->ac_g_ex.fe_len, &ex);
1678
1679 if (max >= ac->ac_g_ex.fe_len && ac->ac_g_ex.fe_len == sbi->s_stripe) {
1680 ext4_fsblk_t start;
1681
1682 start = ext4_group_first_block_no(ac->ac_sb, e4b->bd_group) +
1683 ex.fe_start;
1684 /* use do_div to get remainder (would be 64-bit modulo) */
1685 if (do_div(start, sbi->s_stripe) == 0) {
1686 ac->ac_found++;
1687 ac->ac_b_ex = ex;
1688 ext4_mb_use_best_found(ac, e4b);
1689 }
1690 } else if (max >= ac->ac_g_ex.fe_len) {
1691 BUG_ON(ex.fe_len <= 0);
1692 BUG_ON(ex.fe_group != ac->ac_g_ex.fe_group);
1693 BUG_ON(ex.fe_start != ac->ac_g_ex.fe_start);
1694 ac->ac_found++;
1695 ac->ac_b_ex = ex;
1696 ext4_mb_use_best_found(ac, e4b);
1697 } else if (max > 0 && (ac->ac_flags & EXT4_MB_HINT_MERGE)) {
1698 /* Sometimes, caller may want to merge even small
1699 * number of blocks to an existing extent */
1700 BUG_ON(ex.fe_len <= 0);
1701 BUG_ON(ex.fe_group != ac->ac_g_ex.fe_group);
1702 BUG_ON(ex.fe_start != ac->ac_g_ex.fe_start);
1703 ac->ac_found++;
1704 ac->ac_b_ex = ex;
1705 ext4_mb_use_best_found(ac, e4b);
1706 }
1707 ext4_unlock_group(ac->ac_sb, group);
1708 ext4_mb_unload_buddy(e4b);
1709
1710 return 0;
1711}
1712
1713/*
1714 * The routine scans buddy structures (not bitmap!) from given order
1715 * to max order and tries to find big enough chunk to satisfy the req
1716 */
1717static noinline_for_stack
1718void ext4_mb_simple_scan_group(struct ext4_allocation_context *ac,
1719 struct ext4_buddy *e4b)
1720{
1721 struct super_block *sb = ac->ac_sb;
1722 struct ext4_group_info *grp = e4b->bd_info;
1723 void *buddy;
1724 int i;
1725 int k;
1726 int max;
1727
1728 BUG_ON(ac->ac_2order <= 0);
1729 for (i = ac->ac_2order; i <= sb->s_blocksize_bits + 1; i++) {
1730 if (grp->bb_counters[i] == 0)
1731 continue;
1732
1733 buddy = mb_find_buddy(e4b, i, &max);
1734 BUG_ON(buddy == NULL);
1735
1736 k = mb_find_next_zero_bit(buddy, max, 0);
1737 BUG_ON(k >= max);
1738
1739 ac->ac_found++;
1740
1741 ac->ac_b_ex.fe_len = 1 << i;
1742 ac->ac_b_ex.fe_start = k << i;
1743 ac->ac_b_ex.fe_group = e4b->bd_group;
1744
1745 ext4_mb_use_best_found(ac, e4b);
1746
1747 BUG_ON(ac->ac_b_ex.fe_len != ac->ac_g_ex.fe_len);
1748
1749 if (EXT4_SB(sb)->s_mb_stats)
1750 atomic_inc(&EXT4_SB(sb)->s_bal_2orders);
1751
1752 break;
1753 }
1754}
1755
1756/*
1757 * The routine scans the group and measures all found extents.
1758 * In order to optimize scanning, caller must pass number of
1759 * free blocks in the group, so the routine can know upper limit.
1760 */
1761static noinline_for_stack
1762void ext4_mb_complex_scan_group(struct ext4_allocation_context *ac,
1763 struct ext4_buddy *e4b)
1764{
1765 struct super_block *sb = ac->ac_sb;
1766 void *bitmap = e4b->bd_bitmap;
1767 struct ext4_free_extent ex;
1768 int i;
1769 int free;
1770
1771 free = e4b->bd_info->bb_free;
1772 BUG_ON(free <= 0);
1773
1774 i = e4b->bd_info->bb_first_free;
1775
1776 while (free && ac->ac_status == AC_STATUS_CONTINUE) {
1777 i = mb_find_next_zero_bit(bitmap,
1778 EXT4_CLUSTERS_PER_GROUP(sb), i);
1779 if (i >= EXT4_CLUSTERS_PER_GROUP(sb)) {
1780 /*
1781 * IF we have corrupt bitmap, we won't find any
1782 * free blocks even though group info says we
1783 * we have free blocks
1784 */
1785 ext4_grp_locked_error(sb, e4b->bd_group, 0, 0,
1786 "%d free clusters as per "
1787 "group info. But bitmap says 0",
1788 free);
1789 break;
1790 }
1791
1792 mb_find_extent(e4b, 0, i, ac->ac_g_ex.fe_len, &ex);
1793 BUG_ON(ex.fe_len <= 0);
1794 if (free < ex.fe_len) {
1795 ext4_grp_locked_error(sb, e4b->bd_group, 0, 0,
1796 "%d free clusters as per "
1797 "group info. But got %d blocks",
1798 free, ex.fe_len);
1799 /*
1800 * The number of free blocks differs. This mostly
1801 * indicate that the bitmap is corrupt. So exit
1802 * without claiming the space.
1803 */
1804 break;
1805 }
1806
1807 ext4_mb_measure_extent(ac, &ex, e4b);
1808
1809 i += ex.fe_len;
1810 free -= ex.fe_len;
1811 }
1812
1813 ext4_mb_check_limits(ac, e4b, 1);
1814}
1815
1816/*
1817 * This is a special case for storages like raid5
1818 * we try to find stripe-aligned chunks for stripe-size-multiple requests
1819 */
1820static noinline_for_stack
1821void ext4_mb_scan_aligned(struct ext4_allocation_context *ac,
1822 struct ext4_buddy *e4b)
1823{
1824 struct super_block *sb = ac->ac_sb;
1825 struct ext4_sb_info *sbi = EXT4_SB(sb);
1826 void *bitmap = e4b->bd_bitmap;
1827 struct ext4_free_extent ex;
1828 ext4_fsblk_t first_group_block;
1829 ext4_fsblk_t a;
1830 ext4_grpblk_t i;
1831 int max;
1832
1833 BUG_ON(sbi->s_stripe == 0);
1834
1835 /* find first stripe-aligned block in group */
1836 first_group_block = ext4_group_first_block_no(sb, e4b->bd_group);
1837
1838 a = first_group_block + sbi->s_stripe - 1;
1839 do_div(a, sbi->s_stripe);
1840 i = (a * sbi->s_stripe) - first_group_block;
1841
1842 while (i < EXT4_CLUSTERS_PER_GROUP(sb)) {
1843 if (!mb_test_bit(i, bitmap)) {
1844 max = mb_find_extent(e4b, 0, i, sbi->s_stripe, &ex);
1845 if (max >= sbi->s_stripe) {
1846 ac->ac_found++;
1847 ac->ac_b_ex = ex;
1848 ext4_mb_use_best_found(ac, e4b);
1849 break;
1850 }
1851 }
1852 i += sbi->s_stripe;
1853 }
1854}
1855
1856/* This is now called BEFORE we load the buddy bitmap. */
1857static int ext4_mb_good_group(struct ext4_allocation_context *ac,
1858 ext4_group_t group, int cr)
1859{
1860 unsigned free, fragments;
1861 int flex_size = ext4_flex_bg_size(EXT4_SB(ac->ac_sb));
1862 struct ext4_group_info *grp = ext4_get_group_info(ac->ac_sb, group);
1863
1864 BUG_ON(cr < 0 || cr >= 4);
1865
1866 /* We only do this if the grp has never been initialized */
1867 if (unlikely(EXT4_MB_GRP_NEED_INIT(grp))) {
1868 int ret = ext4_mb_init_group(ac->ac_sb, group);
1869 if (ret)
1870 return 0;
1871 }
1872
1873 free = grp->bb_free;
1874 fragments = grp->bb_fragments;
1875 if (free == 0)
1876 return 0;
1877 if (fragments == 0)
1878 return 0;
1879
1880 switch (cr) {
1881 case 0:
1882 BUG_ON(ac->ac_2order == 0);
1883
1884 if (grp->bb_largest_free_order < ac->ac_2order)
1885 return 0;
1886
1887 /* Avoid using the first bg of a flexgroup for data files */
1888 if ((ac->ac_flags & EXT4_MB_HINT_DATA) &&
1889 (flex_size >= EXT4_FLEX_SIZE_DIR_ALLOC_SCHEME) &&
1890 ((group % flex_size) == 0))
1891 return 0;
1892
1893 return 1;
1894 case 1:
1895 if ((free / fragments) >= ac->ac_g_ex.fe_len)
1896 return 1;
1897 break;
1898 case 2:
1899 if (free >= ac->ac_g_ex.fe_len)
1900 return 1;
1901 break;
1902 case 3:
1903 return 1;
1904 default:
1905 BUG();
1906 }
1907
1908 return 0;
1909}
1910
1911static noinline_for_stack int
1912ext4_mb_regular_allocator(struct ext4_allocation_context *ac)
1913{
1914 ext4_group_t ngroups, group, i;
1915 int cr;
1916 int err = 0;
1917 struct ext4_sb_info *sbi;
1918 struct super_block *sb;
1919 struct ext4_buddy e4b;
1920
1921 sb = ac->ac_sb;
1922 sbi = EXT4_SB(sb);
1923 ngroups = ext4_get_groups_count(sb);
1924 /* non-extent files are limited to low blocks/groups */
1925 if (!(ext4_test_inode_flag(ac->ac_inode, EXT4_INODE_EXTENTS)))
1926 ngroups = sbi->s_blockfile_groups;
1927
1928 BUG_ON(ac->ac_status == AC_STATUS_FOUND);
1929
1930 /* first, try the goal */
1931 err = ext4_mb_find_by_goal(ac, &e4b);
1932 if (err || ac->ac_status == AC_STATUS_FOUND)
1933 goto out;
1934
1935 if (unlikely(ac->ac_flags & EXT4_MB_HINT_GOAL_ONLY))
1936 goto out;
1937
1938 /*
1939 * ac->ac2_order is set only if the fe_len is a power of 2
1940 * if ac2_order is set we also set criteria to 0 so that we
1941 * try exact allocation using buddy.
1942 */
1943 i = fls(ac->ac_g_ex.fe_len);
1944 ac->ac_2order = 0;
1945 /*
1946 * We search using buddy data only if the order of the request
1947 * is greater than equal to the sbi_s_mb_order2_reqs
1948 * You can tune it via /sys/fs/ext4/<partition>/mb_order2_req
1949 */
1950 if (i >= sbi->s_mb_order2_reqs) {
1951 /*
1952 * This should tell if fe_len is exactly power of 2
1953 */
1954 if ((ac->ac_g_ex.fe_len & (~(1 << (i - 1)))) == 0)
1955 ac->ac_2order = i - 1;
1956 }
1957
1958 /* if stream allocation is enabled, use global goal */
1959 if (ac->ac_flags & EXT4_MB_STREAM_ALLOC) {
1960 /* TBD: may be hot point */
1961 spin_lock(&sbi->s_md_lock);
1962 ac->ac_g_ex.fe_group = sbi->s_mb_last_group;
1963 ac->ac_g_ex.fe_start = sbi->s_mb_last_start;
1964 spin_unlock(&sbi->s_md_lock);
1965 }
1966
1967 /* Let's just scan groups to find more-less suitable blocks */
1968 cr = ac->ac_2order ? 0 : 1;
1969 /*
1970 * cr == 0 try to get exact allocation,
1971 * cr == 3 try to get anything
1972 */
1973repeat:
1974 for (; cr < 4 && ac->ac_status == AC_STATUS_CONTINUE; cr++) {
1975 ac->ac_criteria = cr;
1976 /*
1977 * searching for the right group start
1978 * from the goal value specified
1979 */
1980 group = ac->ac_g_ex.fe_group;
1981
1982 for (i = 0; i < ngroups; group++, i++) {
1983 if (group == ngroups)
1984 group = 0;
1985
1986 /* This now checks without needing the buddy page */
1987 if (!ext4_mb_good_group(ac, group, cr))
1988 continue;
1989
1990 err = ext4_mb_load_buddy(sb, group, &e4b);
1991 if (err)
1992 goto out;
1993
1994 ext4_lock_group(sb, group);
1995
1996 /*
1997 * We need to check again after locking the
1998 * block group
1999 */
2000 if (!ext4_mb_good_group(ac, group, cr)) {
2001 ext4_unlock_group(sb, group);
2002 ext4_mb_unload_buddy(&e4b);
2003 continue;
2004 }
2005
2006 ac->ac_groups_scanned++;
2007 if (cr == 0)
2008 ext4_mb_simple_scan_group(ac, &e4b);
2009 else if (cr == 1 && sbi->s_stripe &&
2010 !(ac->ac_g_ex.fe_len % sbi->s_stripe))
2011 ext4_mb_scan_aligned(ac, &e4b);
2012 else
2013 ext4_mb_complex_scan_group(ac, &e4b);
2014
2015 ext4_unlock_group(sb, group);
2016 ext4_mb_unload_buddy(&e4b);
2017
2018 if (ac->ac_status != AC_STATUS_CONTINUE)
2019 break;
2020 }
2021 }
2022
2023 if (ac->ac_b_ex.fe_len > 0 && ac->ac_status != AC_STATUS_FOUND &&
2024 !(ac->ac_flags & EXT4_MB_HINT_FIRST)) {
2025 /*
2026 * We've been searching too long. Let's try to allocate
2027 * the best chunk we've found so far
2028 */
2029
2030 ext4_mb_try_best_found(ac, &e4b);
2031 if (ac->ac_status != AC_STATUS_FOUND) {
2032 /*
2033 * Someone more lucky has already allocated it.
2034 * The only thing we can do is just take first
2035 * found block(s)
2036 printk(KERN_DEBUG "EXT4-fs: someone won our chunk\n");
2037 */
2038 ac->ac_b_ex.fe_group = 0;
2039 ac->ac_b_ex.fe_start = 0;
2040 ac->ac_b_ex.fe_len = 0;
2041 ac->ac_status = AC_STATUS_CONTINUE;
2042 ac->ac_flags |= EXT4_MB_HINT_FIRST;
2043 cr = 3;
2044 atomic_inc(&sbi->s_mb_lost_chunks);
2045 goto repeat;
2046 }
2047 }
2048out:
2049 return err;
2050}
2051
2052static void *ext4_mb_seq_groups_start(struct seq_file *seq, loff_t *pos)
2053{
2054 struct super_block *sb = seq->private;
2055 ext4_group_t group;
2056
2057 if (*pos < 0 || *pos >= ext4_get_groups_count(sb))
2058 return NULL;
2059 group = *pos + 1;
2060 return (void *) ((unsigned long) group);
2061}
2062
2063static void *ext4_mb_seq_groups_next(struct seq_file *seq, void *v, loff_t *pos)
2064{
2065 struct super_block *sb = seq->private;
2066 ext4_group_t group;
2067
2068 ++*pos;
2069 if (*pos < 0 || *pos >= ext4_get_groups_count(sb))
2070 return NULL;
2071 group = *pos + 1;
2072 return (void *) ((unsigned long) group);
2073}
2074
2075static int ext4_mb_seq_groups_show(struct seq_file *seq, void *v)
2076{
2077 struct super_block *sb = seq->private;
2078 ext4_group_t group = (ext4_group_t) ((unsigned long) v);
2079 int i;
2080 int err;
2081 struct ext4_buddy e4b;
2082 struct sg {
2083 struct ext4_group_info info;
2084 ext4_grpblk_t counters[16];
2085 } sg;
2086
2087 group--;
2088 if (group == 0)
2089 seq_printf(seq, "#%-5s: %-5s %-5s %-5s "
2090 "[ %-5s %-5s %-5s %-5s %-5s %-5s %-5s "
2091 "%-5s %-5s %-5s %-5s %-5s %-5s %-5s ]\n",
2092 "group", "free", "frags", "first",
2093 "2^0", "2^1", "2^2", "2^3", "2^4", "2^5", "2^6",
2094 "2^7", "2^8", "2^9", "2^10", "2^11", "2^12", "2^13");
2095
2096 i = (sb->s_blocksize_bits + 2) * sizeof(sg.info.bb_counters[0]) +
2097 sizeof(struct ext4_group_info);
2098 err = ext4_mb_load_buddy(sb, group, &e4b);
2099 if (err) {
2100 seq_printf(seq, "#%-5u: I/O error\n", group);
2101 return 0;
2102 }
2103 ext4_lock_group(sb, group);
2104 memcpy(&sg, ext4_get_group_info(sb, group), i);
2105 ext4_unlock_group(sb, group);
2106 ext4_mb_unload_buddy(&e4b);
2107
2108 seq_printf(seq, "#%-5u: %-5u %-5u %-5u [", group, sg.info.bb_free,
2109 sg.info.bb_fragments, sg.info.bb_first_free);
2110 for (i = 0; i <= 13; i++)
2111 seq_printf(seq, " %-5u", i <= sb->s_blocksize_bits + 1 ?
2112 sg.info.bb_counters[i] : 0);
2113 seq_printf(seq, " ]\n");
2114
2115 return 0;
2116}
2117
2118static void ext4_mb_seq_groups_stop(struct seq_file *seq, void *v)
2119{
2120}
2121
2122static const struct seq_operations ext4_mb_seq_groups_ops = {
2123 .start = ext4_mb_seq_groups_start,
2124 .next = ext4_mb_seq_groups_next,
2125 .stop = ext4_mb_seq_groups_stop,
2126 .show = ext4_mb_seq_groups_show,
2127};
2128
2129static int ext4_mb_seq_groups_open(struct inode *inode, struct file *file)
2130{
2131 struct super_block *sb = PDE(inode)->data;
2132 int rc;
2133
2134 rc = seq_open(file, &ext4_mb_seq_groups_ops);
2135 if (rc == 0) {
2136 struct seq_file *m = file->private_data;
2137 m->private = sb;
2138 }
2139 return rc;
2140
2141}
2142
2143static const struct file_operations ext4_mb_seq_groups_fops = {
2144 .owner = THIS_MODULE,
2145 .open = ext4_mb_seq_groups_open,
2146 .read = seq_read,
2147 .llseek = seq_lseek,
2148 .release = seq_release,
2149};
2150
2151static struct kmem_cache *get_groupinfo_cache(int blocksize_bits)
2152{
2153 int cache_index = blocksize_bits - EXT4_MIN_BLOCK_LOG_SIZE;
2154 struct kmem_cache *cachep = ext4_groupinfo_caches[cache_index];
2155
2156 BUG_ON(!cachep);
2157 return cachep;
2158}
2159
2160/* Create and initialize ext4_group_info data for the given group. */
2161int ext4_mb_add_groupinfo(struct super_block *sb, ext4_group_t group,
2162 struct ext4_group_desc *desc)
2163{
2164 int i;
2165 int metalen = 0;
2166 struct ext4_sb_info *sbi = EXT4_SB(sb);
2167 struct ext4_group_info **meta_group_info;
2168 struct kmem_cache *cachep = get_groupinfo_cache(sb->s_blocksize_bits);
2169
2170 /*
2171 * First check if this group is the first of a reserved block.
2172 * If it's true, we have to allocate a new table of pointers
2173 * to ext4_group_info structures
2174 */
2175 if (group % EXT4_DESC_PER_BLOCK(sb) == 0) {
2176 metalen = sizeof(*meta_group_info) <<
2177 EXT4_DESC_PER_BLOCK_BITS(sb);
2178 meta_group_info = kmalloc(metalen, GFP_KERNEL);
2179 if (meta_group_info == NULL) {
2180 ext4_msg(sb, KERN_ERR, "can't allocate mem "
2181 "for a buddy group");
2182 goto exit_meta_group_info;
2183 }
2184 sbi->s_group_info[group >> EXT4_DESC_PER_BLOCK_BITS(sb)] =
2185 meta_group_info;
2186 }
2187
2188 meta_group_info =
2189 sbi->s_group_info[group >> EXT4_DESC_PER_BLOCK_BITS(sb)];
2190 i = group & (EXT4_DESC_PER_BLOCK(sb) - 1);
2191
2192 meta_group_info[i] = kmem_cache_alloc(cachep, GFP_KERNEL);
2193 if (meta_group_info[i] == NULL) {
2194 ext4_msg(sb, KERN_ERR, "can't allocate buddy mem");
2195 goto exit_group_info;
2196 }
2197 memset(meta_group_info[i], 0, kmem_cache_size(cachep));
2198 set_bit(EXT4_GROUP_INFO_NEED_INIT_BIT,
2199 &(meta_group_info[i]->bb_state));
2200
2201 /*
2202 * initialize bb_free to be able to skip
2203 * empty groups without initialization
2204 */
2205 if (desc->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) {
2206 meta_group_info[i]->bb_free =
2207 ext4_free_clusters_after_init(sb, group, desc);
2208 } else {
2209 meta_group_info[i]->bb_free =
2210 ext4_free_group_clusters(sb, desc);
2211 }
2212
2213 INIT_LIST_HEAD(&meta_group_info[i]->bb_prealloc_list);
2214 init_rwsem(&meta_group_info[i]->alloc_sem);
2215 meta_group_info[i]->bb_free_root = RB_ROOT;
2216 meta_group_info[i]->bb_largest_free_order = -1; /* uninit */
2217
2218#ifdef DOUBLE_CHECK
2219 {
2220 struct buffer_head *bh;
2221 meta_group_info[i]->bb_bitmap =
2222 kmalloc(sb->s_blocksize, GFP_KERNEL);
2223 BUG_ON(meta_group_info[i]->bb_bitmap == NULL);
2224 bh = ext4_read_block_bitmap(sb, group);
2225 BUG_ON(bh == NULL);
2226 memcpy(meta_group_info[i]->bb_bitmap, bh->b_data,
2227 sb->s_blocksize);
2228 put_bh(bh);
2229 }
2230#endif
2231
2232 return 0;
2233
2234exit_group_info:
2235 /* If a meta_group_info table has been allocated, release it now */
2236 if (group % EXT4_DESC_PER_BLOCK(sb) == 0) {
2237 kfree(sbi->s_group_info[group >> EXT4_DESC_PER_BLOCK_BITS(sb)]);
2238 sbi->s_group_info[group >> EXT4_DESC_PER_BLOCK_BITS(sb)] = NULL;
2239 }
2240exit_meta_group_info:
2241 return -ENOMEM;
2242} /* ext4_mb_add_groupinfo */
2243
2244static int ext4_mb_init_backend(struct super_block *sb)
2245{
2246 ext4_group_t ngroups = ext4_get_groups_count(sb);
2247 ext4_group_t i;
2248 struct ext4_sb_info *sbi = EXT4_SB(sb);
2249 struct ext4_super_block *es = sbi->s_es;
2250 int num_meta_group_infos;
2251 int num_meta_group_infos_max;
2252 int array_size;
2253 struct ext4_group_desc *desc;
2254 struct kmem_cache *cachep;
2255
2256 /* This is the number of blocks used by GDT */
2257 num_meta_group_infos = (ngroups + EXT4_DESC_PER_BLOCK(sb) -
2258 1) >> EXT4_DESC_PER_BLOCK_BITS(sb);
2259
2260 /*
2261 * This is the total number of blocks used by GDT including
2262 * the number of reserved blocks for GDT.
2263 * The s_group_info array is allocated with this value
2264 * to allow a clean online resize without a complex
2265 * manipulation of pointer.
2266 * The drawback is the unused memory when no resize
2267 * occurs but it's very low in terms of pages
2268 * (see comments below)
2269 * Need to handle this properly when META_BG resizing is allowed
2270 */
2271 num_meta_group_infos_max = num_meta_group_infos +
2272 le16_to_cpu(es->s_reserved_gdt_blocks);
2273
2274 /*
2275 * array_size is the size of s_group_info array. We round it
2276 * to the next power of two because this approximation is done
2277 * internally by kmalloc so we can have some more memory
2278 * for free here (e.g. may be used for META_BG resize).
2279 */
2280 array_size = 1;
2281 while (array_size < sizeof(*sbi->s_group_info) *
2282 num_meta_group_infos_max)
2283 array_size = array_size << 1;
2284 /* An 8TB filesystem with 64-bit pointers requires a 4096 byte
2285 * kmalloc. A 128kb malloc should suffice for a 256TB filesystem.
2286 * So a two level scheme suffices for now. */
2287 sbi->s_group_info = ext4_kvzalloc(array_size, GFP_KERNEL);
2288 if (sbi->s_group_info == NULL) {
2289 ext4_msg(sb, KERN_ERR, "can't allocate buddy meta group");
2290 return -ENOMEM;
2291 }
2292 sbi->s_buddy_cache = new_inode(sb);
2293 if (sbi->s_buddy_cache == NULL) {
2294 ext4_msg(sb, KERN_ERR, "can't get new inode");
2295 goto err_freesgi;
2296 }
2297 /* To avoid potentially colliding with an valid on-disk inode number,
2298 * use EXT4_BAD_INO for the buddy cache inode number. This inode is
2299 * not in the inode hash, so it should never be found by iget(), but
2300 * this will avoid confusion if it ever shows up during debugging. */
2301 sbi->s_buddy_cache->i_ino = EXT4_BAD_INO;
2302 EXT4_I(sbi->s_buddy_cache)->i_disksize = 0;
2303 for (i = 0; i < ngroups; i++) {
2304 desc = ext4_get_group_desc(sb, i, NULL);
2305 if (desc == NULL) {
2306 ext4_msg(sb, KERN_ERR, "can't read descriptor %u", i);
2307 goto err_freebuddy;
2308 }
2309 if (ext4_mb_add_groupinfo(sb, i, desc) != 0)
2310 goto err_freebuddy;
2311 }
2312
2313 return 0;
2314
2315err_freebuddy:
2316 cachep = get_groupinfo_cache(sb->s_blocksize_bits);
2317 while (i-- > 0)
2318 kmem_cache_free(cachep, ext4_get_group_info(sb, i));
2319 i = num_meta_group_infos;
2320 while (i-- > 0)
2321 kfree(sbi->s_group_info[i]);
2322 iput(sbi->s_buddy_cache);
2323err_freesgi:
2324 ext4_kvfree(sbi->s_group_info);
2325 return -ENOMEM;
2326}
2327
2328static void ext4_groupinfo_destroy_slabs(void)
2329{
2330 int i;
2331
2332 for (i = 0; i < NR_GRPINFO_CACHES; i++) {
2333 if (ext4_groupinfo_caches[i])
2334 kmem_cache_destroy(ext4_groupinfo_caches[i]);
2335 ext4_groupinfo_caches[i] = NULL;
2336 }
2337}
2338
2339static int ext4_groupinfo_create_slab(size_t size)
2340{
2341 static DEFINE_MUTEX(ext4_grpinfo_slab_create_mutex);
2342 int slab_size;
2343 int blocksize_bits = order_base_2(size);
2344 int cache_index = blocksize_bits - EXT4_MIN_BLOCK_LOG_SIZE;
2345 struct kmem_cache *cachep;
2346
2347 if (cache_index >= NR_GRPINFO_CACHES)
2348 return -EINVAL;
2349
2350 if (unlikely(cache_index < 0))
2351 cache_index = 0;
2352
2353 mutex_lock(&ext4_grpinfo_slab_create_mutex);
2354 if (ext4_groupinfo_caches[cache_index]) {
2355 mutex_unlock(&ext4_grpinfo_slab_create_mutex);
2356 return 0; /* Already created */
2357 }
2358
2359 slab_size = offsetof(struct ext4_group_info,
2360 bb_counters[blocksize_bits + 2]);
2361
2362 cachep = kmem_cache_create(ext4_groupinfo_slab_names[cache_index],
2363 slab_size, 0, SLAB_RECLAIM_ACCOUNT,
2364 NULL);
2365
2366 ext4_groupinfo_caches[cache_index] = cachep;
2367
2368 mutex_unlock(&ext4_grpinfo_slab_create_mutex);
2369 if (!cachep) {
2370 printk(KERN_EMERG
2371 "EXT4-fs: no memory for groupinfo slab cache\n");
2372 return -ENOMEM;
2373 }
2374
2375 return 0;
2376}
2377
2378int ext4_mb_init(struct super_block *sb)
2379{
2380 struct ext4_sb_info *sbi = EXT4_SB(sb);
2381 unsigned i, j;
2382 unsigned offset;
2383 unsigned max;
2384 int ret;
2385
2386 i = (sb->s_blocksize_bits + 2) * sizeof(*sbi->s_mb_offsets);
2387
2388 sbi->s_mb_offsets = kmalloc(i, GFP_KERNEL);
2389 if (sbi->s_mb_offsets == NULL) {
2390 ret = -ENOMEM;
2391 goto out;
2392 }
2393
2394 i = (sb->s_blocksize_bits + 2) * sizeof(*sbi->s_mb_maxs);
2395 sbi->s_mb_maxs = kmalloc(i, GFP_KERNEL);
2396 if (sbi->s_mb_maxs == NULL) {
2397 ret = -ENOMEM;
2398 goto out;
2399 }
2400
2401 ret = ext4_groupinfo_create_slab(sb->s_blocksize);
2402 if (ret < 0)
2403 goto out;
2404
2405 /* order 0 is regular bitmap */
2406 sbi->s_mb_maxs[0] = sb->s_blocksize << 3;
2407 sbi->s_mb_offsets[0] = 0;
2408
2409 i = 1;
2410 offset = 0;
2411 max = sb->s_blocksize << 2;
2412 do {
2413 sbi->s_mb_offsets[i] = offset;
2414 sbi->s_mb_maxs[i] = max;
2415 offset += 1 << (sb->s_blocksize_bits - i);
2416 max = max >> 1;
2417 i++;
2418 } while (i <= sb->s_blocksize_bits + 1);
2419
2420 spin_lock_init(&sbi->s_md_lock);
2421 spin_lock_init(&sbi->s_bal_lock);
2422
2423 sbi->s_mb_max_to_scan = MB_DEFAULT_MAX_TO_SCAN;
2424 sbi->s_mb_min_to_scan = MB_DEFAULT_MIN_TO_SCAN;
2425 sbi->s_mb_stats = MB_DEFAULT_STATS;
2426 sbi->s_mb_stream_request = MB_DEFAULT_STREAM_THRESHOLD;
2427 sbi->s_mb_order2_reqs = MB_DEFAULT_ORDER2_REQS;
2428 /*
2429 * The default group preallocation is 512, which for 4k block
2430 * sizes translates to 2 megabytes. However for bigalloc file
2431 * systems, this is probably too big (i.e, if the cluster size
2432 * is 1 megabyte, then group preallocation size becomes half a
2433 * gigabyte!). As a default, we will keep a two megabyte
2434 * group pralloc size for cluster sizes up to 64k, and after
2435 * that, we will force a minimum group preallocation size of
2436 * 32 clusters. This translates to 8 megs when the cluster
2437 * size is 256k, and 32 megs when the cluster size is 1 meg,
2438 * which seems reasonable as a default.
2439 */
2440 sbi->s_mb_group_prealloc = max(MB_DEFAULT_GROUP_PREALLOC >>
2441 sbi->s_cluster_bits, 32);
2442 /*
2443 * If there is a s_stripe > 1, then we set the s_mb_group_prealloc
2444 * to the lowest multiple of s_stripe which is bigger than
2445 * the s_mb_group_prealloc as determined above. We want
2446 * the preallocation size to be an exact multiple of the
2447 * RAID stripe size so that preallocations don't fragment
2448 * the stripes.
2449 */
2450 if (sbi->s_stripe > 1) {
2451 sbi->s_mb_group_prealloc = roundup(
2452 sbi->s_mb_group_prealloc, sbi->s_stripe);
2453 }
2454
2455 sbi->s_locality_groups = alloc_percpu(struct ext4_locality_group);
2456 if (sbi->s_locality_groups == NULL) {
2457 ret = -ENOMEM;
2458 goto out_free_groupinfo_slab;
2459 }
2460 for_each_possible_cpu(i) {
2461 struct ext4_locality_group *lg;
2462 lg = per_cpu_ptr(sbi->s_locality_groups, i);
2463 mutex_init(&lg->lg_mutex);
2464 for (j = 0; j < PREALLOC_TB_SIZE; j++)
2465 INIT_LIST_HEAD(&lg->lg_prealloc_list[j]);
2466 spin_lock_init(&lg->lg_prealloc_lock);
2467 }
2468
2469 /* init file for buddy data */
2470 ret = ext4_mb_init_backend(sb);
2471 if (ret != 0)
2472 goto out_free_locality_groups;
2473
2474 if (sbi->s_proc)
2475 proc_create_data("mb_groups", S_IRUGO, sbi->s_proc,
2476 &ext4_mb_seq_groups_fops, sb);
2477
2478 return 0;
2479
2480out_free_locality_groups:
2481 free_percpu(sbi->s_locality_groups);
2482 sbi->s_locality_groups = NULL;
2483out_free_groupinfo_slab:
2484 ext4_groupinfo_destroy_slabs();
2485out:
2486 kfree(sbi->s_mb_offsets);
2487 sbi->s_mb_offsets = NULL;
2488 kfree(sbi->s_mb_maxs);
2489 sbi->s_mb_maxs = NULL;
2490 return ret;
2491}
2492
2493/* need to called with the ext4 group lock held */
2494static void ext4_mb_cleanup_pa(struct ext4_group_info *grp)
2495{
2496 struct ext4_prealloc_space *pa;
2497 struct list_head *cur, *tmp;
2498 int count = 0;
2499
2500 list_for_each_safe(cur, tmp, &grp->bb_prealloc_list) {
2501 pa = list_entry(cur, struct ext4_prealloc_space, pa_group_list);
2502 list_del(&pa->pa_group_list);
2503 count++;
2504 kmem_cache_free(ext4_pspace_cachep, pa);
2505 }
2506 if (count)
2507 mb_debug(1, "mballoc: %u PAs left\n", count);
2508
2509}
2510
2511int ext4_mb_release(struct super_block *sb)
2512{
2513 ext4_group_t ngroups = ext4_get_groups_count(sb);
2514 ext4_group_t i;
2515 int num_meta_group_infos;
2516 struct ext4_group_info *grinfo;
2517 struct ext4_sb_info *sbi = EXT4_SB(sb);
2518 struct kmem_cache *cachep = get_groupinfo_cache(sb->s_blocksize_bits);
2519
2520 if (sbi->s_proc)
2521 remove_proc_entry("mb_groups", sbi->s_proc);
2522
2523 if (sbi->s_group_info) {
2524 for (i = 0; i < ngroups; i++) {
2525 grinfo = ext4_get_group_info(sb, i);
2526#ifdef DOUBLE_CHECK
2527 kfree(grinfo->bb_bitmap);
2528#endif
2529 ext4_lock_group(sb, i);
2530 ext4_mb_cleanup_pa(grinfo);
2531 ext4_unlock_group(sb, i);
2532 kmem_cache_free(cachep, grinfo);
2533 }
2534 num_meta_group_infos = (ngroups +
2535 EXT4_DESC_PER_BLOCK(sb) - 1) >>
2536 EXT4_DESC_PER_BLOCK_BITS(sb);
2537 for (i = 0; i < num_meta_group_infos; i++)
2538 kfree(sbi->s_group_info[i]);
2539 ext4_kvfree(sbi->s_group_info);
2540 }
2541 kfree(sbi->s_mb_offsets);
2542 kfree(sbi->s_mb_maxs);
2543 if (sbi->s_buddy_cache)
2544 iput(sbi->s_buddy_cache);
2545 if (sbi->s_mb_stats) {
2546 ext4_msg(sb, KERN_INFO,
2547 "mballoc: %u blocks %u reqs (%u success)",
2548 atomic_read(&sbi->s_bal_allocated),
2549 atomic_read(&sbi->s_bal_reqs),
2550 atomic_read(&sbi->s_bal_success));
2551 ext4_msg(sb, KERN_INFO,
2552 "mballoc: %u extents scanned, %u goal hits, "
2553 "%u 2^N hits, %u breaks, %u lost",
2554 atomic_read(&sbi->s_bal_ex_scanned),
2555 atomic_read(&sbi->s_bal_goals),
2556 atomic_read(&sbi->s_bal_2orders),
2557 atomic_read(&sbi->s_bal_breaks),
2558 atomic_read(&sbi->s_mb_lost_chunks));
2559 ext4_msg(sb, KERN_INFO,
2560 "mballoc: %lu generated and it took %Lu",
2561 sbi->s_mb_buddies_generated,
2562 sbi->s_mb_generation_time);
2563 ext4_msg(sb, KERN_INFO,
2564 "mballoc: %u preallocated, %u discarded",
2565 atomic_read(&sbi->s_mb_preallocated),
2566 atomic_read(&sbi->s_mb_discarded));
2567 }
2568
2569 free_percpu(sbi->s_locality_groups);
2570
2571 return 0;
2572}
2573
2574static inline int ext4_issue_discard(struct super_block *sb,
2575 ext4_group_t block_group, ext4_grpblk_t cluster, int count)
2576{
2577 ext4_fsblk_t discard_block;
2578
2579 discard_block = (EXT4_C2B(EXT4_SB(sb), cluster) +
2580 ext4_group_first_block_no(sb, block_group));
2581 count = EXT4_C2B(EXT4_SB(sb), count);
2582 trace_ext4_discard_blocks(sb,
2583 (unsigned long long) discard_block, count);
2584 return sb_issue_discard(sb, discard_block, count, GFP_NOFS, 0);
2585}
2586
2587/*
2588 * This function is called by the jbd2 layer once the commit has finished,
2589 * so we know we can free the blocks that were released with that commit.
2590 */
2591static void ext4_free_data_callback(struct super_block *sb,
2592 struct ext4_journal_cb_entry *jce,
2593 int rc)
2594{
2595 struct ext4_free_data *entry = (struct ext4_free_data *)jce;
2596 struct ext4_buddy e4b;
2597 struct ext4_group_info *db;
2598 int err, count = 0, count2 = 0;
2599
2600 mb_debug(1, "gonna free %u blocks in group %u (0x%p):",
2601 entry->efd_count, entry->efd_group, entry);
2602
2603 if (test_opt(sb, DISCARD))
2604 ext4_issue_discard(sb, entry->efd_group,
2605 entry->efd_start_cluster, entry->efd_count);
2606
2607 err = ext4_mb_load_buddy(sb, entry->efd_group, &e4b);
2608 /* we expect to find existing buddy because it's pinned */
2609 BUG_ON(err != 0);
2610
2611
2612 db = e4b.bd_info;
2613 /* there are blocks to put in buddy to make them really free */
2614 count += entry->efd_count;
2615 count2++;
2616 ext4_lock_group(sb, entry->efd_group);
2617 /* Take it out of per group rb tree */
2618 rb_erase(&entry->efd_node, &(db->bb_free_root));
2619 mb_free_blocks(NULL, &e4b, entry->efd_start_cluster, entry->efd_count);
2620
2621 /*
2622 * Clear the trimmed flag for the group so that the next
2623 * ext4_trim_fs can trim it.
2624 * If the volume is mounted with -o discard, online discard
2625 * is supported and the free blocks will be trimmed online.
2626 */
2627 if (!test_opt(sb, DISCARD))
2628 EXT4_MB_GRP_CLEAR_TRIMMED(db);
2629
2630 if (!db->bb_free_root.rb_node) {
2631 /* No more items in the per group rb tree
2632 * balance refcounts from ext4_mb_free_metadata()
2633 */
2634 page_cache_release(e4b.bd_buddy_page);
2635 page_cache_release(e4b.bd_bitmap_page);
2636 }
2637 ext4_unlock_group(sb, entry->efd_group);
2638 kmem_cache_free(ext4_free_data_cachep, entry);
2639 ext4_mb_unload_buddy(&e4b);
2640
2641 mb_debug(1, "freed %u blocks in %u structures\n", count, count2);
2642}
2643
2644#ifdef CONFIG_EXT4_DEBUG
2645u8 mb_enable_debug __read_mostly;
2646
2647static struct dentry *debugfs_dir;
2648static struct dentry *debugfs_debug;
2649
2650static void __init ext4_create_debugfs_entry(void)
2651{
2652 debugfs_dir = debugfs_create_dir("ext4", NULL);
2653 if (debugfs_dir)
2654 debugfs_debug = debugfs_create_u8("mballoc-debug",
2655 S_IRUGO | S_IWUSR,
2656 debugfs_dir,
2657 &mb_enable_debug);
2658}
2659
2660static void ext4_remove_debugfs_entry(void)
2661{
2662 debugfs_remove(debugfs_debug);
2663 debugfs_remove(debugfs_dir);
2664}
2665
2666#else
2667
2668static void __init ext4_create_debugfs_entry(void)
2669{
2670}
2671
2672static void ext4_remove_debugfs_entry(void)
2673{
2674}
2675
2676#endif
2677
2678int __init ext4_init_mballoc(void)
2679{
2680 ext4_pspace_cachep = KMEM_CACHE(ext4_prealloc_space,
2681 SLAB_RECLAIM_ACCOUNT);
2682 if (ext4_pspace_cachep == NULL)
2683 return -ENOMEM;
2684
2685 ext4_ac_cachep = KMEM_CACHE(ext4_allocation_context,
2686 SLAB_RECLAIM_ACCOUNT);
2687 if (ext4_ac_cachep == NULL) {
2688 kmem_cache_destroy(ext4_pspace_cachep);
2689 return -ENOMEM;
2690 }
2691
2692 ext4_free_data_cachep = KMEM_CACHE(ext4_free_data,
2693 SLAB_RECLAIM_ACCOUNT);
2694 if (ext4_free_data_cachep == NULL) {
2695 kmem_cache_destroy(ext4_pspace_cachep);
2696 kmem_cache_destroy(ext4_ac_cachep);
2697 return -ENOMEM;
2698 }
2699 ext4_create_debugfs_entry();
2700 return 0;
2701}
2702
2703void ext4_exit_mballoc(void)
2704{
2705 /*
2706 * Wait for completion of call_rcu()'s on ext4_pspace_cachep
2707 * before destroying the slab cache.
2708 */
2709 rcu_barrier();
2710 kmem_cache_destroy(ext4_pspace_cachep);
2711 kmem_cache_destroy(ext4_ac_cachep);
2712 kmem_cache_destroy(ext4_free_data_cachep);
2713 ext4_groupinfo_destroy_slabs();
2714 ext4_remove_debugfs_entry();
2715}
2716
2717
2718/*
2719 * Check quota and mark chosen space (ac->ac_b_ex) non-free in bitmaps
2720 * Returns 0 if success or error code
2721 */
2722static noinline_for_stack int
2723ext4_mb_mark_diskspace_used(struct ext4_allocation_context *ac,
2724 handle_t *handle, unsigned int reserv_clstrs)
2725{
2726 struct buffer_head *bitmap_bh = NULL;
2727 struct ext4_group_desc *gdp;
2728 struct buffer_head *gdp_bh;
2729 struct ext4_sb_info *sbi;
2730 struct super_block *sb;
2731 ext4_fsblk_t block;
2732 int err, len;
2733
2734 BUG_ON(ac->ac_status != AC_STATUS_FOUND);
2735 BUG_ON(ac->ac_b_ex.fe_len <= 0);
2736
2737 sb = ac->ac_sb;
2738 sbi = EXT4_SB(sb);
2739
2740 err = -EIO;
2741 bitmap_bh = ext4_read_block_bitmap(sb, ac->ac_b_ex.fe_group);
2742 if (!bitmap_bh)
2743 goto out_err;
2744
2745 err = ext4_journal_get_write_access(handle, bitmap_bh);
2746 if (err)
2747 goto out_err;
2748
2749 err = -EIO;
2750 gdp = ext4_get_group_desc(sb, ac->ac_b_ex.fe_group, &gdp_bh);
2751 if (!gdp)
2752 goto out_err;
2753
2754 ext4_debug("using block group %u(%d)\n", ac->ac_b_ex.fe_group,
2755 ext4_free_group_clusters(sb, gdp));
2756
2757 err = ext4_journal_get_write_access(handle, gdp_bh);
2758 if (err)
2759 goto out_err;
2760
2761 block = ext4_grp_offs_to_block(sb, &ac->ac_b_ex);
2762
2763 len = EXT4_C2B(sbi, ac->ac_b_ex.fe_len);
2764 if (!ext4_data_block_valid(sbi, block, len)) {
2765 ext4_error(sb, "Allocating blocks %llu-%llu which overlap "
2766 "fs metadata", block, block+len);
2767 /* File system mounted not to panic on error
2768 * Fix the bitmap and repeat the block allocation
2769 * We leak some of the blocks here.
2770 */
2771 ext4_lock_group(sb, ac->ac_b_ex.fe_group);
2772 ext4_set_bits(bitmap_bh->b_data, ac->ac_b_ex.fe_start,
2773 ac->ac_b_ex.fe_len);
2774 ext4_unlock_group(sb, ac->ac_b_ex.fe_group);
2775 err = ext4_handle_dirty_metadata(handle, NULL, bitmap_bh);
2776 if (!err)
2777 err = -EAGAIN;
2778 goto out_err;
2779 }
2780
2781 ext4_lock_group(sb, ac->ac_b_ex.fe_group);
2782#ifdef AGGRESSIVE_CHECK
2783 {
2784 int i;
2785 for (i = 0; i < ac->ac_b_ex.fe_len; i++) {
2786 BUG_ON(mb_test_bit(ac->ac_b_ex.fe_start + i,
2787 bitmap_bh->b_data));
2788 }
2789 }
2790#endif
2791 ext4_set_bits(bitmap_bh->b_data, ac->ac_b_ex.fe_start,
2792 ac->ac_b_ex.fe_len);
2793 if (gdp->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) {
2794 gdp->bg_flags &= cpu_to_le16(~EXT4_BG_BLOCK_UNINIT);
2795 ext4_free_group_clusters_set(sb, gdp,
2796 ext4_free_clusters_after_init(sb,
2797 ac->ac_b_ex.fe_group, gdp));
2798 }
2799 len = ext4_free_group_clusters(sb, gdp) - ac->ac_b_ex.fe_len;
2800 ext4_free_group_clusters_set(sb, gdp, len);
2801 ext4_block_bitmap_csum_set(sb, ac->ac_b_ex.fe_group, gdp, bitmap_bh,
2802 EXT4_BLOCKS_PER_GROUP(sb) / 8);
2803 ext4_group_desc_csum_set(sb, ac->ac_b_ex.fe_group, gdp);
2804
2805 ext4_unlock_group(sb, ac->ac_b_ex.fe_group);
2806 percpu_counter_sub(&sbi->s_freeclusters_counter, ac->ac_b_ex.fe_len);
2807 /*
2808 * Now reduce the dirty block count also. Should not go negative
2809 */
2810 if (!(ac->ac_flags & EXT4_MB_DELALLOC_RESERVED))
2811 /* release all the reserved blocks if non delalloc */
2812 percpu_counter_sub(&sbi->s_dirtyclusters_counter,
2813 reserv_clstrs);
2814
2815 if (sbi->s_log_groups_per_flex) {
2816 ext4_group_t flex_group = ext4_flex_group(sbi,
2817 ac->ac_b_ex.fe_group);
2818 atomic_sub(ac->ac_b_ex.fe_len,
2819 &sbi->s_flex_groups[flex_group].free_clusters);
2820 }
2821
2822 err = ext4_handle_dirty_metadata(handle, NULL, bitmap_bh);
2823 if (err)
2824 goto out_err;
2825 err = ext4_handle_dirty_metadata(handle, NULL, gdp_bh);
2826
2827out_err:
2828 ext4_mark_super_dirty(sb);
2829 brelse(bitmap_bh);
2830 return err;
2831}
2832
2833/*
2834 * here we normalize request for locality group
2835 * Group request are normalized to s_mb_group_prealloc, which goes to
2836 * s_strip if we set the same via mount option.
2837 * s_mb_group_prealloc can be configured via
2838 * /sys/fs/ext4/<partition>/mb_group_prealloc
2839 *
2840 * XXX: should we try to preallocate more than the group has now?
2841 */
2842static void ext4_mb_normalize_group_request(struct ext4_allocation_context *ac)
2843{
2844 struct super_block *sb = ac->ac_sb;
2845 struct ext4_locality_group *lg = ac->ac_lg;
2846
2847 BUG_ON(lg == NULL);
2848 ac->ac_g_ex.fe_len = EXT4_SB(sb)->s_mb_group_prealloc;
2849 mb_debug(1, "#%u: goal %u blocks for locality group\n",
2850 current->pid, ac->ac_g_ex.fe_len);
2851}
2852
2853/*
2854 * Normalization means making request better in terms of
2855 * size and alignment
2856 */
2857static noinline_for_stack void
2858ext4_mb_normalize_request(struct ext4_allocation_context *ac,
2859 struct ext4_allocation_request *ar)
2860{
2861 struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
2862 int bsbits, max;
2863 ext4_lblk_t end;
2864 loff_t size, start_off;
2865 loff_t orig_size __maybe_unused;
2866 ext4_lblk_t start;
2867 struct ext4_inode_info *ei = EXT4_I(ac->ac_inode);
2868 struct ext4_prealloc_space *pa;
2869
2870 /* do normalize only data requests, metadata requests
2871 do not need preallocation */
2872 if (!(ac->ac_flags & EXT4_MB_HINT_DATA))
2873 return;
2874
2875 /* sometime caller may want exact blocks */
2876 if (unlikely(ac->ac_flags & EXT4_MB_HINT_GOAL_ONLY))
2877 return;
2878
2879 /* caller may indicate that preallocation isn't
2880 * required (it's a tail, for example) */
2881 if (ac->ac_flags & EXT4_MB_HINT_NOPREALLOC)
2882 return;
2883
2884 if (ac->ac_flags & EXT4_MB_HINT_GROUP_ALLOC) {
2885 ext4_mb_normalize_group_request(ac);
2886 return ;
2887 }
2888
2889 bsbits = ac->ac_sb->s_blocksize_bits;
2890
2891 /* first, let's learn actual file size
2892 * given current request is allocated */
2893 size = ac->ac_o_ex.fe_logical + EXT4_C2B(sbi, ac->ac_o_ex.fe_len);
2894 size = size << bsbits;
2895 if (size < i_size_read(ac->ac_inode))
2896 size = i_size_read(ac->ac_inode);
2897 orig_size = size;
2898
2899 /* max size of free chunks */
2900 max = 2 << bsbits;
2901
2902#define NRL_CHECK_SIZE(req, size, max, chunk_size) \
2903 (req <= (size) || max <= (chunk_size))
2904
2905 /* first, try to predict filesize */
2906 /* XXX: should this table be tunable? */
2907 start_off = 0;
2908 if (size <= 16 * 1024) {
2909 size = 16 * 1024;
2910 } else if (size <= 32 * 1024) {
2911 size = 32 * 1024;
2912 } else if (size <= 64 * 1024) {
2913 size = 64 * 1024;
2914 } else if (size <= 128 * 1024) {
2915 size = 128 * 1024;
2916 } else if (size <= 256 * 1024) {
2917 size = 256 * 1024;
2918 } else if (size <= 512 * 1024) {
2919 size = 512 * 1024;
2920 } else if (size <= 1024 * 1024) {
2921 size = 1024 * 1024;
2922 } else if (NRL_CHECK_SIZE(size, 4 * 1024 * 1024, max, 2 * 1024)) {
2923 start_off = ((loff_t)ac->ac_o_ex.fe_logical >>
2924 (21 - bsbits)) << 21;
2925 size = 2 * 1024 * 1024;
2926 } else if (NRL_CHECK_SIZE(size, 8 * 1024 * 1024, max, 4 * 1024)) {
2927 start_off = ((loff_t)ac->ac_o_ex.fe_logical >>
2928 (22 - bsbits)) << 22;
2929 size = 4 * 1024 * 1024;
2930 } else if (NRL_CHECK_SIZE(ac->ac_o_ex.fe_len,
2931 (8<<20)>>bsbits, max, 8 * 1024)) {
2932 start_off = ((loff_t)ac->ac_o_ex.fe_logical >>
2933 (23 - bsbits)) << 23;
2934 size = 8 * 1024 * 1024;
2935 } else {
2936 start_off = (loff_t)ac->ac_o_ex.fe_logical << bsbits;
2937 size = ac->ac_o_ex.fe_len << bsbits;
2938 }
2939 size = size >> bsbits;
2940 start = start_off >> bsbits;
2941
2942 /* don't cover already allocated blocks in selected range */
2943 if (ar->pleft && start <= ar->lleft) {
2944 size -= ar->lleft + 1 - start;
2945 start = ar->lleft + 1;
2946 }
2947 if (ar->pright && start + size - 1 >= ar->lright)
2948 size -= start + size - ar->lright;
2949
2950 end = start + size;
2951
2952 /* check we don't cross already preallocated blocks */
2953 rcu_read_lock();
2954 list_for_each_entry_rcu(pa, &ei->i_prealloc_list, pa_inode_list) {
2955 ext4_lblk_t pa_end;
2956
2957 if (pa->pa_deleted)
2958 continue;
2959 spin_lock(&pa->pa_lock);
2960 if (pa->pa_deleted) {
2961 spin_unlock(&pa->pa_lock);
2962 continue;
2963 }
2964
2965 pa_end = pa->pa_lstart + EXT4_C2B(EXT4_SB(ac->ac_sb),
2966 pa->pa_len);
2967
2968 /* PA must not overlap original request */
2969 BUG_ON(!(ac->ac_o_ex.fe_logical >= pa_end ||
2970 ac->ac_o_ex.fe_logical < pa->pa_lstart));
2971
2972 /* skip PAs this normalized request doesn't overlap with */
2973 if (pa->pa_lstart >= end || pa_end <= start) {
2974 spin_unlock(&pa->pa_lock);
2975 continue;
2976 }
2977 BUG_ON(pa->pa_lstart <= start && pa_end >= end);
2978
2979 /* adjust start or end to be adjacent to this pa */
2980 if (pa_end <= ac->ac_o_ex.fe_logical) {
2981 BUG_ON(pa_end < start);
2982 start = pa_end;
2983 } else if (pa->pa_lstart > ac->ac_o_ex.fe_logical) {
2984 BUG_ON(pa->pa_lstart > end);
2985 end = pa->pa_lstart;
2986 }
2987 spin_unlock(&pa->pa_lock);
2988 }
2989 rcu_read_unlock();
2990 size = end - start;
2991
2992 /* XXX: extra loop to check we really don't overlap preallocations */
2993 rcu_read_lock();
2994 list_for_each_entry_rcu(pa, &ei->i_prealloc_list, pa_inode_list) {
2995 ext4_lblk_t pa_end;
2996
2997 spin_lock(&pa->pa_lock);
2998 if (pa->pa_deleted == 0) {
2999 pa_end = pa->pa_lstart + EXT4_C2B(EXT4_SB(ac->ac_sb),
3000 pa->pa_len);
3001 BUG_ON(!(start >= pa_end || end <= pa->pa_lstart));
3002 }
3003 spin_unlock(&pa->pa_lock);
3004 }
3005 rcu_read_unlock();
3006
3007 if (start + size <= ac->ac_o_ex.fe_logical &&
3008 start > ac->ac_o_ex.fe_logical) {
3009 ext4_msg(ac->ac_sb, KERN_ERR,
3010 "start %lu, size %lu, fe_logical %lu",
3011 (unsigned long) start, (unsigned long) size,
3012 (unsigned long) ac->ac_o_ex.fe_logical);
3013 }
3014 BUG_ON(start + size <= ac->ac_o_ex.fe_logical &&
3015 start > ac->ac_o_ex.fe_logical);
3016 BUG_ON(size <= 0 || size > EXT4_CLUSTERS_PER_GROUP(ac->ac_sb));
3017
3018 /* now prepare goal request */
3019
3020 /* XXX: is it better to align blocks WRT to logical
3021 * placement or satisfy big request as is */
3022 ac->ac_g_ex.fe_logical = start;
3023 ac->ac_g_ex.fe_len = EXT4_NUM_B2C(sbi, size);
3024
3025 /* define goal start in order to merge */
3026 if (ar->pright && (ar->lright == (start + size))) {
3027 /* merge to the right */
3028 ext4_get_group_no_and_offset(ac->ac_sb, ar->pright - size,
3029 &ac->ac_f_ex.fe_group,
3030 &ac->ac_f_ex.fe_start);
3031 ac->ac_flags |= EXT4_MB_HINT_TRY_GOAL;
3032 }
3033 if (ar->pleft && (ar->lleft + 1 == start)) {
3034 /* merge to the left */
3035 ext4_get_group_no_and_offset(ac->ac_sb, ar->pleft + 1,
3036 &ac->ac_f_ex.fe_group,
3037 &ac->ac_f_ex.fe_start);
3038 ac->ac_flags |= EXT4_MB_HINT_TRY_GOAL;
3039 }
3040
3041 mb_debug(1, "goal: %u(was %u) blocks at %u\n", (unsigned) size,
3042 (unsigned) orig_size, (unsigned) start);
3043}
3044
3045static void ext4_mb_collect_stats(struct ext4_allocation_context *ac)
3046{
3047 struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
3048
3049 if (sbi->s_mb_stats && ac->ac_g_ex.fe_len > 1) {
3050 atomic_inc(&sbi->s_bal_reqs);
3051 atomic_add(ac->ac_b_ex.fe_len, &sbi->s_bal_allocated);
3052 if (ac->ac_b_ex.fe_len >= ac->ac_o_ex.fe_len)
3053 atomic_inc(&sbi->s_bal_success);
3054 atomic_add(ac->ac_found, &sbi->s_bal_ex_scanned);
3055 if (ac->ac_g_ex.fe_start == ac->ac_b_ex.fe_start &&
3056 ac->ac_g_ex.fe_group == ac->ac_b_ex.fe_group)
3057 atomic_inc(&sbi->s_bal_goals);
3058 if (ac->ac_found > sbi->s_mb_max_to_scan)
3059 atomic_inc(&sbi->s_bal_breaks);
3060 }
3061
3062 if (ac->ac_op == EXT4_MB_HISTORY_ALLOC)
3063 trace_ext4_mballoc_alloc(ac);
3064 else
3065 trace_ext4_mballoc_prealloc(ac);
3066}
3067
3068/*
3069 * Called on failure; free up any blocks from the inode PA for this
3070 * context. We don't need this for MB_GROUP_PA because we only change
3071 * pa_free in ext4_mb_release_context(), but on failure, we've already
3072 * zeroed out ac->ac_b_ex.fe_len, so group_pa->pa_free is not changed.
3073 */
3074static void ext4_discard_allocated_blocks(struct ext4_allocation_context *ac)
3075{
3076 struct ext4_prealloc_space *pa = ac->ac_pa;
3077
3078 if (pa && pa->pa_type == MB_INODE_PA)
3079 pa->pa_free += ac->ac_b_ex.fe_len;
3080}
3081
3082/*
3083 * use blocks preallocated to inode
3084 */
3085static void ext4_mb_use_inode_pa(struct ext4_allocation_context *ac,
3086 struct ext4_prealloc_space *pa)
3087{
3088 struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
3089 ext4_fsblk_t start;
3090 ext4_fsblk_t end;
3091 int len;
3092
3093 /* found preallocated blocks, use them */
3094 start = pa->pa_pstart + (ac->ac_o_ex.fe_logical - pa->pa_lstart);
3095 end = min(pa->pa_pstart + EXT4_C2B(sbi, pa->pa_len),
3096 start + EXT4_C2B(sbi, ac->ac_o_ex.fe_len));
3097 len = EXT4_NUM_B2C(sbi, end - start);
3098 ext4_get_group_no_and_offset(ac->ac_sb, start, &ac->ac_b_ex.fe_group,
3099 &ac->ac_b_ex.fe_start);
3100 ac->ac_b_ex.fe_len = len;
3101 ac->ac_status = AC_STATUS_FOUND;
3102 ac->ac_pa = pa;
3103
3104 BUG_ON(start < pa->pa_pstart);
3105 BUG_ON(end > pa->pa_pstart + EXT4_C2B(sbi, pa->pa_len));
3106 BUG_ON(pa->pa_free < len);
3107 pa->pa_free -= len;
3108
3109 mb_debug(1, "use %llu/%u from inode pa %p\n", start, len, pa);
3110}
3111
3112/*
3113 * use blocks preallocated to locality group
3114 */
3115static void ext4_mb_use_group_pa(struct ext4_allocation_context *ac,
3116 struct ext4_prealloc_space *pa)
3117{
3118 unsigned int len = ac->ac_o_ex.fe_len;
3119
3120 ext4_get_group_no_and_offset(ac->ac_sb, pa->pa_pstart,
3121 &ac->ac_b_ex.fe_group,
3122 &ac->ac_b_ex.fe_start);
3123 ac->ac_b_ex.fe_len = len;
3124 ac->ac_status = AC_STATUS_FOUND;
3125 ac->ac_pa = pa;
3126
3127 /* we don't correct pa_pstart or pa_plen here to avoid
3128 * possible race when the group is being loaded concurrently
3129 * instead we correct pa later, after blocks are marked
3130 * in on-disk bitmap -- see ext4_mb_release_context()
3131 * Other CPUs are prevented from allocating from this pa by lg_mutex
3132 */
3133 mb_debug(1, "use %u/%u from group pa %p\n", pa->pa_lstart-len, len, pa);
3134}
3135
3136/*
3137 * Return the prealloc space that have minimal distance
3138 * from the goal block. @cpa is the prealloc
3139 * space that is having currently known minimal distance
3140 * from the goal block.
3141 */
3142static struct ext4_prealloc_space *
3143ext4_mb_check_group_pa(ext4_fsblk_t goal_block,
3144 struct ext4_prealloc_space *pa,
3145 struct ext4_prealloc_space *cpa)
3146{
3147 ext4_fsblk_t cur_distance, new_distance;
3148
3149 if (cpa == NULL) {
3150 atomic_inc(&pa->pa_count);
3151 return pa;
3152 }
3153 cur_distance = abs(goal_block - cpa->pa_pstart);
3154 new_distance = abs(goal_block - pa->pa_pstart);
3155
3156 if (cur_distance <= new_distance)
3157 return cpa;
3158
3159 /* drop the previous reference */
3160 atomic_dec(&cpa->pa_count);
3161 atomic_inc(&pa->pa_count);
3162 return pa;
3163}
3164
3165/*
3166 * search goal blocks in preallocated space
3167 */
3168static noinline_for_stack int
3169ext4_mb_use_preallocated(struct ext4_allocation_context *ac)
3170{
3171 struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
3172 int order, i;
3173 struct ext4_inode_info *ei = EXT4_I(ac->ac_inode);
3174 struct ext4_locality_group *lg;
3175 struct ext4_prealloc_space *pa, *cpa = NULL;
3176 ext4_fsblk_t goal_block;
3177
3178 /* only data can be preallocated */
3179 if (!(ac->ac_flags & EXT4_MB_HINT_DATA))
3180 return 0;
3181
3182 /* first, try per-file preallocation */
3183 rcu_read_lock();
3184 list_for_each_entry_rcu(pa, &ei->i_prealloc_list, pa_inode_list) {
3185
3186 /* all fields in this condition don't change,
3187 * so we can skip locking for them */
3188 if (ac->ac_o_ex.fe_logical < pa->pa_lstart ||
3189 ac->ac_o_ex.fe_logical >= (pa->pa_lstart +
3190 EXT4_C2B(sbi, pa->pa_len)))
3191 continue;
3192
3193 /* non-extent files can't have physical blocks past 2^32 */
3194 if (!(ext4_test_inode_flag(ac->ac_inode, EXT4_INODE_EXTENTS)) &&
3195 (pa->pa_pstart + EXT4_C2B(sbi, pa->pa_len) >
3196 EXT4_MAX_BLOCK_FILE_PHYS))
3197 continue;
3198
3199 /* found preallocated blocks, use them */
3200 spin_lock(&pa->pa_lock);
3201 if (pa->pa_deleted == 0 && pa->pa_free) {
3202 atomic_inc(&pa->pa_count);
3203 ext4_mb_use_inode_pa(ac, pa);
3204 spin_unlock(&pa->pa_lock);
3205 ac->ac_criteria = 10;
3206 rcu_read_unlock();
3207 return 1;
3208 }
3209 spin_unlock(&pa->pa_lock);
3210 }
3211 rcu_read_unlock();
3212
3213 /* can we use group allocation? */
3214 if (!(ac->ac_flags & EXT4_MB_HINT_GROUP_ALLOC))
3215 return 0;
3216
3217 /* inode may have no locality group for some reason */
3218 lg = ac->ac_lg;
3219 if (lg == NULL)
3220 return 0;
3221 order = fls(ac->ac_o_ex.fe_len) - 1;
3222 if (order > PREALLOC_TB_SIZE - 1)
3223 /* The max size of hash table is PREALLOC_TB_SIZE */
3224 order = PREALLOC_TB_SIZE - 1;
3225
3226 goal_block = ext4_grp_offs_to_block(ac->ac_sb, &ac->ac_g_ex);
3227 /*
3228 * search for the prealloc space that is having
3229 * minimal distance from the goal block.
3230 */
3231 for (i = order; i < PREALLOC_TB_SIZE; i++) {
3232 rcu_read_lock();
3233 list_for_each_entry_rcu(pa, &lg->lg_prealloc_list[i],
3234 pa_inode_list) {
3235 spin_lock(&pa->pa_lock);
3236 if (pa->pa_deleted == 0 &&
3237 pa->pa_free >= ac->ac_o_ex.fe_len) {
3238
3239 cpa = ext4_mb_check_group_pa(goal_block,
3240 pa, cpa);
3241 }
3242 spin_unlock(&pa->pa_lock);
3243 }
3244 rcu_read_unlock();
3245 }
3246 if (cpa) {
3247 ext4_mb_use_group_pa(ac, cpa);
3248 ac->ac_criteria = 20;
3249 return 1;
3250 }
3251 return 0;
3252}
3253
3254/*
3255 * the function goes through all block freed in the group
3256 * but not yet committed and marks them used in in-core bitmap.
3257 * buddy must be generated from this bitmap
3258 * Need to be called with the ext4 group lock held
3259 */
3260static void ext4_mb_generate_from_freelist(struct super_block *sb, void *bitmap,
3261 ext4_group_t group)
3262{
3263 struct rb_node *n;
3264 struct ext4_group_info *grp;
3265 struct ext4_free_data *entry;
3266
3267 grp = ext4_get_group_info(sb, group);
3268 n = rb_first(&(grp->bb_free_root));
3269
3270 while (n) {
3271 entry = rb_entry(n, struct ext4_free_data, efd_node);
3272 ext4_set_bits(bitmap, entry->efd_start_cluster, entry->efd_count);
3273 n = rb_next(n);
3274 }
3275 return;
3276}
3277
3278/*
3279 * the function goes through all preallocation in this group and marks them
3280 * used in in-core bitmap. buddy must be generated from this bitmap
3281 * Need to be called with ext4 group lock held
3282 */
3283static noinline_for_stack
3284void ext4_mb_generate_from_pa(struct super_block *sb, void *bitmap,
3285 ext4_group_t group)
3286{
3287 struct ext4_group_info *grp = ext4_get_group_info(sb, group);
3288 struct ext4_prealloc_space *pa;
3289 struct list_head *cur;
3290 ext4_group_t groupnr;
3291 ext4_grpblk_t start;
3292 int preallocated = 0;
3293 int len;
3294
3295 /* all form of preallocation discards first load group,
3296 * so the only competing code is preallocation use.
3297 * we don't need any locking here
3298 * notice we do NOT ignore preallocations with pa_deleted
3299 * otherwise we could leave used blocks available for
3300 * allocation in buddy when concurrent ext4_mb_put_pa()
3301 * is dropping preallocation
3302 */
3303 list_for_each(cur, &grp->bb_prealloc_list) {
3304 pa = list_entry(cur, struct ext4_prealloc_space, pa_group_list);
3305 spin_lock(&pa->pa_lock);
3306 ext4_get_group_no_and_offset(sb, pa->pa_pstart,
3307 &groupnr, &start);
3308 len = pa->pa_len;
3309 spin_unlock(&pa->pa_lock);
3310 if (unlikely(len == 0))
3311 continue;
3312 BUG_ON(groupnr != group);
3313 ext4_set_bits(bitmap, start, len);
3314 preallocated += len;
3315 }
3316 mb_debug(1, "prellocated %u for group %u\n", preallocated, group);
3317}
3318
3319static void ext4_mb_pa_callback(struct rcu_head *head)
3320{
3321 struct ext4_prealloc_space *pa;
3322 pa = container_of(head, struct ext4_prealloc_space, u.pa_rcu);
3323 kmem_cache_free(ext4_pspace_cachep, pa);
3324}
3325
3326/*
3327 * drops a reference to preallocated space descriptor
3328 * if this was the last reference and the space is consumed
3329 */
3330static void ext4_mb_put_pa(struct ext4_allocation_context *ac,
3331 struct super_block *sb, struct ext4_prealloc_space *pa)
3332{
3333 ext4_group_t grp;
3334 ext4_fsblk_t grp_blk;
3335
3336 if (!atomic_dec_and_test(&pa->pa_count) || pa->pa_free != 0)
3337 return;
3338
3339 /* in this short window concurrent discard can set pa_deleted */
3340 spin_lock(&pa->pa_lock);
3341 if (pa->pa_deleted == 1) {
3342 spin_unlock(&pa->pa_lock);
3343 return;
3344 }
3345
3346 pa->pa_deleted = 1;
3347 spin_unlock(&pa->pa_lock);
3348
3349 grp_blk = pa->pa_pstart;
3350 /*
3351 * If doing group-based preallocation, pa_pstart may be in the
3352 * next group when pa is used up
3353 */
3354 if (pa->pa_type == MB_GROUP_PA)
3355 grp_blk--;
3356
3357 ext4_get_group_no_and_offset(sb, grp_blk, &grp, NULL);
3358
3359 /*
3360 * possible race:
3361 *
3362 * P1 (buddy init) P2 (regular allocation)
3363 * find block B in PA
3364 * copy on-disk bitmap to buddy
3365 * mark B in on-disk bitmap
3366 * drop PA from group
3367 * mark all PAs in buddy
3368 *
3369 * thus, P1 initializes buddy with B available. to prevent this
3370 * we make "copy" and "mark all PAs" atomic and serialize "drop PA"
3371 * against that pair
3372 */
3373 ext4_lock_group(sb, grp);
3374 list_del(&pa->pa_group_list);
3375 ext4_unlock_group(sb, grp);
3376
3377 spin_lock(pa->pa_obj_lock);
3378 list_del_rcu(&pa->pa_inode_list);
3379 spin_unlock(pa->pa_obj_lock);
3380
3381 call_rcu(&(pa)->u.pa_rcu, ext4_mb_pa_callback);
3382}
3383
3384/*
3385 * creates new preallocated space for given inode
3386 */
3387static noinline_for_stack int
3388ext4_mb_new_inode_pa(struct ext4_allocation_context *ac)
3389{
3390 struct super_block *sb = ac->ac_sb;
3391 struct ext4_sb_info *sbi = EXT4_SB(sb);
3392 struct ext4_prealloc_space *pa;
3393 struct ext4_group_info *grp;
3394 struct ext4_inode_info *ei;
3395
3396 /* preallocate only when found space is larger then requested */
3397 BUG_ON(ac->ac_o_ex.fe_len >= ac->ac_b_ex.fe_len);
3398 BUG_ON(ac->ac_status != AC_STATUS_FOUND);
3399 BUG_ON(!S_ISREG(ac->ac_inode->i_mode));
3400
3401 pa = kmem_cache_alloc(ext4_pspace_cachep, GFP_NOFS);
3402 if (pa == NULL)
3403 return -ENOMEM;
3404
3405 if (ac->ac_b_ex.fe_len < ac->ac_g_ex.fe_len) {
3406 int winl;
3407 int wins;
3408 int win;
3409 int offs;
3410
3411 /* we can't allocate as much as normalizer wants.
3412 * so, found space must get proper lstart
3413 * to cover original request */
3414 BUG_ON(ac->ac_g_ex.fe_logical > ac->ac_o_ex.fe_logical);
3415 BUG_ON(ac->ac_g_ex.fe_len < ac->ac_o_ex.fe_len);
3416
3417 /* we're limited by original request in that
3418 * logical block must be covered any way
3419 * winl is window we can move our chunk within */
3420 winl = ac->ac_o_ex.fe_logical - ac->ac_g_ex.fe_logical;
3421
3422 /* also, we should cover whole original request */
3423 wins = EXT4_C2B(sbi, ac->ac_b_ex.fe_len - ac->ac_o_ex.fe_len);
3424
3425 /* the smallest one defines real window */
3426 win = min(winl, wins);
3427
3428 offs = ac->ac_o_ex.fe_logical %
3429 EXT4_C2B(sbi, ac->ac_b_ex.fe_len);
3430 if (offs && offs < win)
3431 win = offs;
3432
3433 ac->ac_b_ex.fe_logical = ac->ac_o_ex.fe_logical -
3434 EXT4_B2C(sbi, win);
3435 BUG_ON(ac->ac_o_ex.fe_logical < ac->ac_b_ex.fe_logical);
3436 BUG_ON(ac->ac_o_ex.fe_len > ac->ac_b_ex.fe_len);
3437 }
3438
3439 /* preallocation can change ac_b_ex, thus we store actually
3440 * allocated blocks for history */
3441 ac->ac_f_ex = ac->ac_b_ex;
3442
3443 pa->pa_lstart = ac->ac_b_ex.fe_logical;
3444 pa->pa_pstart = ext4_grp_offs_to_block(sb, &ac->ac_b_ex);
3445 pa->pa_len = ac->ac_b_ex.fe_len;
3446 pa->pa_free = pa->pa_len;
3447 atomic_set(&pa->pa_count, 1);
3448 spin_lock_init(&pa->pa_lock);
3449 INIT_LIST_HEAD(&pa->pa_inode_list);
3450 INIT_LIST_HEAD(&pa->pa_group_list);
3451 pa->pa_deleted = 0;
3452 pa->pa_type = MB_INODE_PA;
3453
3454 mb_debug(1, "new inode pa %p: %llu/%u for %u\n", pa,
3455 pa->pa_pstart, pa->pa_len, pa->pa_lstart);
3456 trace_ext4_mb_new_inode_pa(ac, pa);
3457
3458 ext4_mb_use_inode_pa(ac, pa);
3459 atomic_add(pa->pa_free, &sbi->s_mb_preallocated);
3460
3461 ei = EXT4_I(ac->ac_inode);
3462 grp = ext4_get_group_info(sb, ac->ac_b_ex.fe_group);
3463
3464 pa->pa_obj_lock = &ei->i_prealloc_lock;
3465 pa->pa_inode = ac->ac_inode;
3466
3467 ext4_lock_group(sb, ac->ac_b_ex.fe_group);
3468 list_add(&pa->pa_group_list, &grp->bb_prealloc_list);
3469 ext4_unlock_group(sb, ac->ac_b_ex.fe_group);
3470
3471 spin_lock(pa->pa_obj_lock);
3472 list_add_rcu(&pa->pa_inode_list, &ei->i_prealloc_list);
3473 spin_unlock(pa->pa_obj_lock);
3474
3475 return 0;
3476}
3477
3478/*
3479 * creates new preallocated space for locality group inodes belongs to
3480 */
3481static noinline_for_stack int
3482ext4_mb_new_group_pa(struct ext4_allocation_context *ac)
3483{
3484 struct super_block *sb = ac->ac_sb;
3485 struct ext4_locality_group *lg;
3486 struct ext4_prealloc_space *pa;
3487 struct ext4_group_info *grp;
3488
3489 /* preallocate only when found space is larger then requested */
3490 BUG_ON(ac->ac_o_ex.fe_len >= ac->ac_b_ex.fe_len);
3491 BUG_ON(ac->ac_status != AC_STATUS_FOUND);
3492 BUG_ON(!S_ISREG(ac->ac_inode->i_mode));
3493
3494 BUG_ON(ext4_pspace_cachep == NULL);
3495 pa = kmem_cache_alloc(ext4_pspace_cachep, GFP_NOFS);
3496 if (pa == NULL)
3497 return -ENOMEM;
3498
3499 /* preallocation can change ac_b_ex, thus we store actually
3500 * allocated blocks for history */
3501 ac->ac_f_ex = ac->ac_b_ex;
3502
3503 pa->pa_pstart = ext4_grp_offs_to_block(sb, &ac->ac_b_ex);
3504 pa->pa_lstart = pa->pa_pstart;
3505 pa->pa_len = ac->ac_b_ex.fe_len;
3506 pa->pa_free = pa->pa_len;
3507 atomic_set(&pa->pa_count, 1);
3508 spin_lock_init(&pa->pa_lock);
3509 INIT_LIST_HEAD(&pa->pa_inode_list);
3510 INIT_LIST_HEAD(&pa->pa_group_list);
3511 pa->pa_deleted = 0;
3512 pa->pa_type = MB_GROUP_PA;
3513
3514 mb_debug(1, "new group pa %p: %llu/%u for %u\n", pa,
3515 pa->pa_pstart, pa->pa_len, pa->pa_lstart);
3516 trace_ext4_mb_new_group_pa(ac, pa);
3517
3518 ext4_mb_use_group_pa(ac, pa);
3519 atomic_add(pa->pa_free, &EXT4_SB(sb)->s_mb_preallocated);
3520
3521 grp = ext4_get_group_info(sb, ac->ac_b_ex.fe_group);
3522 lg = ac->ac_lg;
3523 BUG_ON(lg == NULL);
3524
3525 pa->pa_obj_lock = &lg->lg_prealloc_lock;
3526 pa->pa_inode = NULL;
3527
3528 ext4_lock_group(sb, ac->ac_b_ex.fe_group);
3529 list_add(&pa->pa_group_list, &grp->bb_prealloc_list);
3530 ext4_unlock_group(sb, ac->ac_b_ex.fe_group);
3531
3532 /*
3533 * We will later add the new pa to the right bucket
3534 * after updating the pa_free in ext4_mb_release_context
3535 */
3536 return 0;
3537}
3538
3539static int ext4_mb_new_preallocation(struct ext4_allocation_context *ac)
3540{
3541 int err;
3542
3543 if (ac->ac_flags & EXT4_MB_HINT_GROUP_ALLOC)
3544 err = ext4_mb_new_group_pa(ac);
3545 else
3546 err = ext4_mb_new_inode_pa(ac);
3547 return err;
3548}
3549
3550/*
3551 * finds all unused blocks in on-disk bitmap, frees them in
3552 * in-core bitmap and buddy.
3553 * @pa must be unlinked from inode and group lists, so that
3554 * nobody else can find/use it.
3555 * the caller MUST hold group/inode locks.
3556 * TODO: optimize the case when there are no in-core structures yet
3557 */
3558static noinline_for_stack int
3559ext4_mb_release_inode_pa(struct ext4_buddy *e4b, struct buffer_head *bitmap_bh,
3560 struct ext4_prealloc_space *pa)
3561{
3562 struct super_block *sb = e4b->bd_sb;
3563 struct ext4_sb_info *sbi = EXT4_SB(sb);
3564 unsigned int end;
3565 unsigned int next;
3566 ext4_group_t group;
3567 ext4_grpblk_t bit;
3568 unsigned long long grp_blk_start;
3569 int err = 0;
3570 int free = 0;
3571
3572 BUG_ON(pa->pa_deleted == 0);
3573 ext4_get_group_no_and_offset(sb, pa->pa_pstart, &group, &bit);
3574 grp_blk_start = pa->pa_pstart - EXT4_C2B(sbi, bit);
3575 BUG_ON(group != e4b->bd_group && pa->pa_len != 0);
3576 end = bit + pa->pa_len;
3577
3578 while (bit < end) {
3579 bit = mb_find_next_zero_bit(bitmap_bh->b_data, end, bit);
3580 if (bit >= end)
3581 break;
3582 next = mb_find_next_bit(bitmap_bh->b_data, end, bit);
3583 mb_debug(1, " free preallocated %u/%u in group %u\n",
3584 (unsigned) ext4_group_first_block_no(sb, group) + bit,
3585 (unsigned) next - bit, (unsigned) group);
3586 free += next - bit;
3587
3588 trace_ext4_mballoc_discard(sb, NULL, group, bit, next - bit);
3589 trace_ext4_mb_release_inode_pa(pa, (grp_blk_start +
3590 EXT4_C2B(sbi, bit)),
3591 next - bit);
3592 mb_free_blocks(pa->pa_inode, e4b, bit, next - bit);
3593 bit = next + 1;
3594 }
3595 if (free != pa->pa_free) {
3596 ext4_msg(e4b->bd_sb, KERN_CRIT,
3597 "pa %p: logic %lu, phys. %lu, len %lu",
3598 pa, (unsigned long) pa->pa_lstart,
3599 (unsigned long) pa->pa_pstart,
3600 (unsigned long) pa->pa_len);
3601 ext4_grp_locked_error(sb, group, 0, 0, "free %u, pa_free %u",
3602 free, pa->pa_free);
3603 /*
3604 * pa is already deleted so we use the value obtained
3605 * from the bitmap and continue.
3606 */
3607 }
3608 atomic_add(free, &sbi->s_mb_discarded);
3609
3610 return err;
3611}
3612
3613static noinline_for_stack int
3614ext4_mb_release_group_pa(struct ext4_buddy *e4b,
3615 struct ext4_prealloc_space *pa)
3616{
3617 struct super_block *sb = e4b->bd_sb;
3618 ext4_group_t group;
3619 ext4_grpblk_t bit;
3620
3621 trace_ext4_mb_release_group_pa(sb, pa);
3622 BUG_ON(pa->pa_deleted == 0);
3623 ext4_get_group_no_and_offset(sb, pa->pa_pstart, &group, &bit);
3624 BUG_ON(group != e4b->bd_group && pa->pa_len != 0);
3625 mb_free_blocks(pa->pa_inode, e4b, bit, pa->pa_len);
3626 atomic_add(pa->pa_len, &EXT4_SB(sb)->s_mb_discarded);
3627 trace_ext4_mballoc_discard(sb, NULL, group, bit, pa->pa_len);
3628
3629 return 0;
3630}
3631
3632/*
3633 * releases all preallocations in given group
3634 *
3635 * first, we need to decide discard policy:
3636 * - when do we discard
3637 * 1) ENOSPC
3638 * - how many do we discard
3639 * 1) how many requested
3640 */
3641static noinline_for_stack int
3642ext4_mb_discard_group_preallocations(struct super_block *sb,
3643 ext4_group_t group, int needed)
3644{
3645 struct ext4_group_info *grp = ext4_get_group_info(sb, group);
3646 struct buffer_head *bitmap_bh = NULL;
3647 struct ext4_prealloc_space *pa, *tmp;
3648 struct list_head list;
3649 struct ext4_buddy e4b;
3650 int err;
3651 int busy = 0;
3652 int free = 0;
3653
3654 mb_debug(1, "discard preallocation for group %u\n", group);
3655
3656 if (list_empty(&grp->bb_prealloc_list))
3657 return 0;
3658
3659 bitmap_bh = ext4_read_block_bitmap(sb, group);
3660 if (bitmap_bh == NULL) {
3661 ext4_error(sb, "Error reading block bitmap for %u", group);
3662 return 0;
3663 }
3664
3665 err = ext4_mb_load_buddy(sb, group, &e4b);
3666 if (err) {
3667 ext4_error(sb, "Error loading buddy information for %u", group);
3668 put_bh(bitmap_bh);
3669 return 0;
3670 }
3671
3672 if (needed == 0)
3673 needed = EXT4_CLUSTERS_PER_GROUP(sb) + 1;
3674
3675 INIT_LIST_HEAD(&list);
3676repeat:
3677 ext4_lock_group(sb, group);
3678 list_for_each_entry_safe(pa, tmp,
3679 &grp->bb_prealloc_list, pa_group_list) {
3680 spin_lock(&pa->pa_lock);
3681 if (atomic_read(&pa->pa_count)) {
3682 spin_unlock(&pa->pa_lock);
3683 busy = 1;
3684 continue;
3685 }
3686 if (pa->pa_deleted) {
3687 spin_unlock(&pa->pa_lock);
3688 continue;
3689 }
3690
3691 /* seems this one can be freed ... */
3692 pa->pa_deleted = 1;
3693
3694 /* we can trust pa_free ... */
3695 free += pa->pa_free;
3696
3697 spin_unlock(&pa->pa_lock);
3698
3699 list_del(&pa->pa_group_list);
3700 list_add(&pa->u.pa_tmp_list, &list);
3701 }
3702
3703 /* if we still need more blocks and some PAs were used, try again */
3704 if (free < needed && busy) {
3705 busy = 0;
3706 ext4_unlock_group(sb, group);
3707 /*
3708 * Yield the CPU here so that we don't get soft lockup
3709 * in non preempt case.
3710 */
3711 yield();
3712 goto repeat;
3713 }
3714
3715 /* found anything to free? */
3716 if (list_empty(&list)) {
3717 BUG_ON(free != 0);
3718 goto out;
3719 }
3720
3721 /* now free all selected PAs */
3722 list_for_each_entry_safe(pa, tmp, &list, u.pa_tmp_list) {
3723
3724 /* remove from object (inode or locality group) */
3725 spin_lock(pa->pa_obj_lock);
3726 list_del_rcu(&pa->pa_inode_list);
3727 spin_unlock(pa->pa_obj_lock);
3728
3729 if (pa->pa_type == MB_GROUP_PA)
3730 ext4_mb_release_group_pa(&e4b, pa);
3731 else
3732 ext4_mb_release_inode_pa(&e4b, bitmap_bh, pa);
3733
3734 list_del(&pa->u.pa_tmp_list);
3735 call_rcu(&(pa)->u.pa_rcu, ext4_mb_pa_callback);
3736 }
3737
3738out:
3739 ext4_unlock_group(sb, group);
3740 ext4_mb_unload_buddy(&e4b);
3741 put_bh(bitmap_bh);
3742 return free;
3743}
3744
3745/*
3746 * releases all non-used preallocated blocks for given inode
3747 *
3748 * It's important to discard preallocations under i_data_sem
3749 * We don't want another block to be served from the prealloc
3750 * space when we are discarding the inode prealloc space.
3751 *
3752 * FIXME!! Make sure it is valid at all the call sites
3753 */
3754void ext4_discard_preallocations(struct inode *inode)
3755{
3756 struct ext4_inode_info *ei = EXT4_I(inode);
3757 struct super_block *sb = inode->i_sb;
3758 struct buffer_head *bitmap_bh = NULL;
3759 struct ext4_prealloc_space *pa, *tmp;
3760 ext4_group_t group = 0;
3761 struct list_head list;
3762 struct ext4_buddy e4b;
3763 int err;
3764
3765 if (!S_ISREG(inode->i_mode)) {
3766 /*BUG_ON(!list_empty(&ei->i_prealloc_list));*/
3767 return;
3768 }
3769
3770 mb_debug(1, "discard preallocation for inode %lu\n", inode->i_ino);
3771 trace_ext4_discard_preallocations(inode);
3772
3773 INIT_LIST_HEAD(&list);
3774
3775repeat:
3776 /* first, collect all pa's in the inode */
3777 spin_lock(&ei->i_prealloc_lock);
3778 while (!list_empty(&ei->i_prealloc_list)) {
3779 pa = list_entry(ei->i_prealloc_list.next,
3780 struct ext4_prealloc_space, pa_inode_list);
3781 BUG_ON(pa->pa_obj_lock != &ei->i_prealloc_lock);
3782 spin_lock(&pa->pa_lock);
3783 if (atomic_read(&pa->pa_count)) {
3784 /* this shouldn't happen often - nobody should
3785 * use preallocation while we're discarding it */
3786 spin_unlock(&pa->pa_lock);
3787 spin_unlock(&ei->i_prealloc_lock);
3788 ext4_msg(sb, KERN_ERR,
3789 "uh-oh! used pa while discarding");
3790 WARN_ON(1);
3791 schedule_timeout_uninterruptible(HZ);
3792 goto repeat;
3793
3794 }
3795 if (pa->pa_deleted == 0) {
3796 pa->pa_deleted = 1;
3797 spin_unlock(&pa->pa_lock);
3798 list_del_rcu(&pa->pa_inode_list);
3799 list_add(&pa->u.pa_tmp_list, &list);
3800 continue;
3801 }
3802
3803 /* someone is deleting pa right now */
3804 spin_unlock(&pa->pa_lock);
3805 spin_unlock(&ei->i_prealloc_lock);
3806
3807 /* we have to wait here because pa_deleted
3808 * doesn't mean pa is already unlinked from
3809 * the list. as we might be called from
3810 * ->clear_inode() the inode will get freed
3811 * and concurrent thread which is unlinking
3812 * pa from inode's list may access already
3813 * freed memory, bad-bad-bad */
3814
3815 /* XXX: if this happens too often, we can
3816 * add a flag to force wait only in case
3817 * of ->clear_inode(), but not in case of
3818 * regular truncate */
3819 schedule_timeout_uninterruptible(HZ);
3820 goto repeat;
3821 }
3822 spin_unlock(&ei->i_prealloc_lock);
3823
3824 list_for_each_entry_safe(pa, tmp, &list, u.pa_tmp_list) {
3825 BUG_ON(pa->pa_type != MB_INODE_PA);
3826 ext4_get_group_no_and_offset(sb, pa->pa_pstart, &group, NULL);
3827
3828 err = ext4_mb_load_buddy(sb, group, &e4b);
3829 if (err) {
3830 ext4_error(sb, "Error loading buddy information for %u",
3831 group);
3832 continue;
3833 }
3834
3835 bitmap_bh = ext4_read_block_bitmap(sb, group);
3836 if (bitmap_bh == NULL) {
3837 ext4_error(sb, "Error reading block bitmap for %u",
3838 group);
3839 ext4_mb_unload_buddy(&e4b);
3840 continue;
3841 }
3842
3843 ext4_lock_group(sb, group);
3844 list_del(&pa->pa_group_list);
3845 ext4_mb_release_inode_pa(&e4b, bitmap_bh, pa);
3846 ext4_unlock_group(sb, group);
3847
3848 ext4_mb_unload_buddy(&e4b);
3849 put_bh(bitmap_bh);
3850
3851 list_del(&pa->u.pa_tmp_list);
3852 call_rcu(&(pa)->u.pa_rcu, ext4_mb_pa_callback);
3853 }
3854}
3855
3856#ifdef CONFIG_EXT4_DEBUG
3857static void ext4_mb_show_ac(struct ext4_allocation_context *ac)
3858{
3859 struct super_block *sb = ac->ac_sb;
3860 ext4_group_t ngroups, i;
3861
3862 if (!mb_enable_debug ||
3863 (EXT4_SB(sb)->s_mount_flags & EXT4_MF_FS_ABORTED))
3864 return;
3865
3866 ext4_msg(ac->ac_sb, KERN_ERR, "Can't allocate:"
3867 " Allocation context details:");
3868 ext4_msg(ac->ac_sb, KERN_ERR, "status %d flags %d",
3869 ac->ac_status, ac->ac_flags);
3870 ext4_msg(ac->ac_sb, KERN_ERR, "orig %lu/%lu/%lu@%lu, "
3871 "goal %lu/%lu/%lu@%lu, "
3872 "best %lu/%lu/%lu@%lu cr %d",
3873 (unsigned long)ac->ac_o_ex.fe_group,
3874 (unsigned long)ac->ac_o_ex.fe_start,
3875 (unsigned long)ac->ac_o_ex.fe_len,
3876 (unsigned long)ac->ac_o_ex.fe_logical,
3877 (unsigned long)ac->ac_g_ex.fe_group,
3878 (unsigned long)ac->ac_g_ex.fe_start,
3879 (unsigned long)ac->ac_g_ex.fe_len,
3880 (unsigned long)ac->ac_g_ex.fe_logical,
3881 (unsigned long)ac->ac_b_ex.fe_group,
3882 (unsigned long)ac->ac_b_ex.fe_start,
3883 (unsigned long)ac->ac_b_ex.fe_len,
3884 (unsigned long)ac->ac_b_ex.fe_logical,
3885 (int)ac->ac_criteria);
3886 ext4_msg(ac->ac_sb, KERN_ERR, "%lu scanned, %d found",
3887 ac->ac_ex_scanned, ac->ac_found);
3888 ext4_msg(ac->ac_sb, KERN_ERR, "groups: ");
3889 ngroups = ext4_get_groups_count(sb);
3890 for (i = 0; i < ngroups; i++) {
3891 struct ext4_group_info *grp = ext4_get_group_info(sb, i);
3892 struct ext4_prealloc_space *pa;
3893 ext4_grpblk_t start;
3894 struct list_head *cur;
3895 ext4_lock_group(sb, i);
3896 list_for_each(cur, &grp->bb_prealloc_list) {
3897 pa = list_entry(cur, struct ext4_prealloc_space,
3898 pa_group_list);
3899 spin_lock(&pa->pa_lock);
3900 ext4_get_group_no_and_offset(sb, pa->pa_pstart,
3901 NULL, &start);
3902 spin_unlock(&pa->pa_lock);
3903 printk(KERN_ERR "PA:%u:%d:%u \n", i,
3904 start, pa->pa_len);
3905 }
3906 ext4_unlock_group(sb, i);
3907
3908 if (grp->bb_free == 0)
3909 continue;
3910 printk(KERN_ERR "%u: %d/%d \n",
3911 i, grp->bb_free, grp->bb_fragments);
3912 }
3913 printk(KERN_ERR "\n");
3914}
3915#else
3916static inline void ext4_mb_show_ac(struct ext4_allocation_context *ac)
3917{
3918 return;
3919}
3920#endif
3921
3922/*
3923 * We use locality group preallocation for small size file. The size of the
3924 * file is determined by the current size or the resulting size after
3925 * allocation which ever is larger
3926 *
3927 * One can tune this size via /sys/fs/ext4/<partition>/mb_stream_req
3928 */
3929static void ext4_mb_group_or_file(struct ext4_allocation_context *ac)
3930{
3931 struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
3932 int bsbits = ac->ac_sb->s_blocksize_bits;
3933 loff_t size, isize;
3934
3935 if (!(ac->ac_flags & EXT4_MB_HINT_DATA))
3936 return;
3937
3938 if (unlikely(ac->ac_flags & EXT4_MB_HINT_GOAL_ONLY))
3939 return;
3940
3941 size = ac->ac_o_ex.fe_logical + EXT4_C2B(sbi, ac->ac_o_ex.fe_len);
3942 isize = (i_size_read(ac->ac_inode) + ac->ac_sb->s_blocksize - 1)
3943 >> bsbits;
3944
3945 if ((size == isize) &&
3946 !ext4_fs_is_busy(sbi) &&
3947 (atomic_read(&ac->ac_inode->i_writecount) == 0)) {
3948 ac->ac_flags |= EXT4_MB_HINT_NOPREALLOC;
3949 return;
3950 }
3951
3952 if (sbi->s_mb_group_prealloc <= 0) {
3953 ac->ac_flags |= EXT4_MB_STREAM_ALLOC;
3954 return;
3955 }
3956
3957 /* don't use group allocation for large files */
3958 size = max(size, isize);
3959 if (size > sbi->s_mb_stream_request) {
3960 ac->ac_flags |= EXT4_MB_STREAM_ALLOC;
3961 return;
3962 }
3963
3964 BUG_ON(ac->ac_lg != NULL);
3965 /*
3966 * locality group prealloc space are per cpu. The reason for having
3967 * per cpu locality group is to reduce the contention between block
3968 * request from multiple CPUs.
3969 */
3970 ac->ac_lg = __this_cpu_ptr(sbi->s_locality_groups);
3971
3972 /* we're going to use group allocation */
3973 ac->ac_flags |= EXT4_MB_HINT_GROUP_ALLOC;
3974
3975 /* serialize all allocations in the group */
3976 mutex_lock(&ac->ac_lg->lg_mutex);
3977}
3978
3979static noinline_for_stack int
3980ext4_mb_initialize_context(struct ext4_allocation_context *ac,
3981 struct ext4_allocation_request *ar)
3982{
3983 struct super_block *sb = ar->inode->i_sb;
3984 struct ext4_sb_info *sbi = EXT4_SB(sb);
3985 struct ext4_super_block *es = sbi->s_es;
3986 ext4_group_t group;
3987 unsigned int len;
3988 ext4_fsblk_t goal;
3989 ext4_grpblk_t block;
3990
3991 /* we can't allocate > group size */
3992 len = ar->len;
3993
3994 /* just a dirty hack to filter too big requests */
3995 if (len >= EXT4_CLUSTERS_PER_GROUP(sb) - 10)
3996 len = EXT4_CLUSTERS_PER_GROUP(sb) - 10;
3997
3998 /* start searching from the goal */
3999 goal = ar->goal;
4000 if (goal < le32_to_cpu(es->s_first_data_block) ||
4001 goal >= ext4_blocks_count(es))
4002 goal = le32_to_cpu(es->s_first_data_block);
4003 ext4_get_group_no_and_offset(sb, goal, &group, &block);
4004
4005 /* set up allocation goals */
4006 memset(ac, 0, sizeof(struct ext4_allocation_context));
4007 ac->ac_b_ex.fe_logical = ar->logical & ~(sbi->s_cluster_ratio - 1);
4008 ac->ac_status = AC_STATUS_CONTINUE;
4009 ac->ac_sb = sb;
4010 ac->ac_inode = ar->inode;
4011 ac->ac_o_ex.fe_logical = ac->ac_b_ex.fe_logical;
4012 ac->ac_o_ex.fe_group = group;
4013 ac->ac_o_ex.fe_start = block;
4014 ac->ac_o_ex.fe_len = len;
4015 ac->ac_g_ex = ac->ac_o_ex;
4016 ac->ac_flags = ar->flags;
4017
4018 /* we have to define context: we'll we work with a file or
4019 * locality group. this is a policy, actually */
4020 ext4_mb_group_or_file(ac);
4021
4022 mb_debug(1, "init ac: %u blocks @ %u, goal %u, flags %x, 2^%d, "
4023 "left: %u/%u, right %u/%u to %swritable\n",
4024 (unsigned) ar->len, (unsigned) ar->logical,
4025 (unsigned) ar->goal, ac->ac_flags, ac->ac_2order,
4026 (unsigned) ar->lleft, (unsigned) ar->pleft,
4027 (unsigned) ar->lright, (unsigned) ar->pright,
4028 atomic_read(&ar->inode->i_writecount) ? "" : "non-");
4029 return 0;
4030
4031}
4032
4033static noinline_for_stack void
4034ext4_mb_discard_lg_preallocations(struct super_block *sb,
4035 struct ext4_locality_group *lg,
4036 int order, int total_entries)
4037{
4038 ext4_group_t group = 0;
4039 struct ext4_buddy e4b;
4040 struct list_head discard_list;
4041 struct ext4_prealloc_space *pa, *tmp;
4042
4043 mb_debug(1, "discard locality group preallocation\n");
4044
4045 INIT_LIST_HEAD(&discard_list);
4046
4047 spin_lock(&lg->lg_prealloc_lock);
4048 list_for_each_entry_rcu(pa, &lg->lg_prealloc_list[order],
4049 pa_inode_list) {
4050 spin_lock(&pa->pa_lock);
4051 if (atomic_read(&pa->pa_count)) {
4052 /*
4053 * This is the pa that we just used
4054 * for block allocation. So don't
4055 * free that
4056 */
4057 spin_unlock(&pa->pa_lock);
4058 continue;
4059 }
4060 if (pa->pa_deleted) {
4061 spin_unlock(&pa->pa_lock);
4062 continue;
4063 }
4064 /* only lg prealloc space */
4065 BUG_ON(pa->pa_type != MB_GROUP_PA);
4066
4067 /* seems this one can be freed ... */
4068 pa->pa_deleted = 1;
4069 spin_unlock(&pa->pa_lock);
4070
4071 list_del_rcu(&pa->pa_inode_list);
4072 list_add(&pa->u.pa_tmp_list, &discard_list);
4073
4074 total_entries--;
4075 if (total_entries <= 5) {
4076 /*
4077 * we want to keep only 5 entries
4078 * allowing it to grow to 8. This
4079 * mak sure we don't call discard
4080 * soon for this list.
4081 */
4082 break;
4083 }
4084 }
4085 spin_unlock(&lg->lg_prealloc_lock);
4086
4087 list_for_each_entry_safe(pa, tmp, &discard_list, u.pa_tmp_list) {
4088
4089 ext4_get_group_no_and_offset(sb, pa->pa_pstart, &group, NULL);
4090 if (ext4_mb_load_buddy(sb, group, &e4b)) {
4091 ext4_error(sb, "Error loading buddy information for %u",
4092 group);
4093 continue;
4094 }
4095 ext4_lock_group(sb, group);
4096 list_del(&pa->pa_group_list);
4097 ext4_mb_release_group_pa(&e4b, pa);
4098 ext4_unlock_group(sb, group);
4099
4100 ext4_mb_unload_buddy(&e4b);
4101 list_del(&pa->u.pa_tmp_list);
4102 call_rcu(&(pa)->u.pa_rcu, ext4_mb_pa_callback);
4103 }
4104}
4105
4106/*
4107 * We have incremented pa_count. So it cannot be freed at this
4108 * point. Also we hold lg_mutex. So no parallel allocation is
4109 * possible from this lg. That means pa_free cannot be updated.
4110 *
4111 * A parallel ext4_mb_discard_group_preallocations is possible.
4112 * which can cause the lg_prealloc_list to be updated.
4113 */
4114
4115static void ext4_mb_add_n_trim(struct ext4_allocation_context *ac)
4116{
4117 int order, added = 0, lg_prealloc_count = 1;
4118 struct super_block *sb = ac->ac_sb;
4119 struct ext4_locality_group *lg = ac->ac_lg;
4120 struct ext4_prealloc_space *tmp_pa, *pa = ac->ac_pa;
4121
4122 order = fls(pa->pa_free) - 1;
4123 if (order > PREALLOC_TB_SIZE - 1)
4124 /* The max size of hash table is PREALLOC_TB_SIZE */
4125 order = PREALLOC_TB_SIZE - 1;
4126 /* Add the prealloc space to lg */
4127 rcu_read_lock();
4128 list_for_each_entry_rcu(tmp_pa, &lg->lg_prealloc_list[order],
4129 pa_inode_list) {
4130 spin_lock(&tmp_pa->pa_lock);
4131 if (tmp_pa->pa_deleted) {
4132 spin_unlock(&tmp_pa->pa_lock);
4133 continue;
4134 }
4135 if (!added && pa->pa_free < tmp_pa->pa_free) {
4136 /* Add to the tail of the previous entry */
4137 list_add_tail_rcu(&pa->pa_inode_list,
4138 &tmp_pa->pa_inode_list);
4139 added = 1;
4140 /*
4141 * we want to count the total
4142 * number of entries in the list
4143 */
4144 }
4145 spin_unlock(&tmp_pa->pa_lock);
4146 lg_prealloc_count++;
4147 }
4148 if (!added)
4149 list_add_tail_rcu(&pa->pa_inode_list,
4150 &lg->lg_prealloc_list[order]);
4151 rcu_read_unlock();
4152
4153 /* Now trim the list to be not more than 8 elements */
4154 if (lg_prealloc_count > 8) {
4155 ext4_mb_discard_lg_preallocations(sb, lg,
4156 order, lg_prealloc_count);
4157 return;
4158 }
4159 return ;
4160}
4161
4162/*
4163 * release all resource we used in allocation
4164 */
4165static int ext4_mb_release_context(struct ext4_allocation_context *ac)
4166{
4167 struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
4168 struct ext4_prealloc_space *pa = ac->ac_pa;
4169 if (pa) {
4170 if (pa->pa_type == MB_GROUP_PA) {
4171 /* see comment in ext4_mb_use_group_pa() */
4172 spin_lock(&pa->pa_lock);
4173 pa->pa_pstart += EXT4_C2B(sbi, ac->ac_b_ex.fe_len);
4174 pa->pa_lstart += EXT4_C2B(sbi, ac->ac_b_ex.fe_len);
4175 pa->pa_free -= ac->ac_b_ex.fe_len;
4176 pa->pa_len -= ac->ac_b_ex.fe_len;
4177 spin_unlock(&pa->pa_lock);
4178 }
4179 }
4180 if (pa) {
4181 /*
4182 * We want to add the pa to the right bucket.
4183 * Remove it from the list and while adding
4184 * make sure the list to which we are adding
4185 * doesn't grow big.
4186 */
4187 if ((pa->pa_type == MB_GROUP_PA) && likely(pa->pa_free)) {
4188 spin_lock(pa->pa_obj_lock);
4189 list_del_rcu(&pa->pa_inode_list);
4190 spin_unlock(pa->pa_obj_lock);
4191 ext4_mb_add_n_trim(ac);
4192 }
4193 ext4_mb_put_pa(ac, ac->ac_sb, pa);
4194 }
4195 if (ac->ac_bitmap_page)
4196 page_cache_release(ac->ac_bitmap_page);
4197 if (ac->ac_buddy_page)
4198 page_cache_release(ac->ac_buddy_page);
4199 if (ac->ac_flags & EXT4_MB_HINT_GROUP_ALLOC)
4200 mutex_unlock(&ac->ac_lg->lg_mutex);
4201 ext4_mb_collect_stats(ac);
4202 return 0;
4203}
4204
4205static int ext4_mb_discard_preallocations(struct super_block *sb, int needed)
4206{
4207 ext4_group_t i, ngroups = ext4_get_groups_count(sb);
4208 int ret;
4209 int freed = 0;
4210
4211 trace_ext4_mb_discard_preallocations(sb, needed);
4212 for (i = 0; i < ngroups && needed > 0; i++) {
4213 ret = ext4_mb_discard_group_preallocations(sb, i, needed);
4214 freed += ret;
4215 needed -= ret;
4216 }
4217
4218 return freed;
4219}
4220
4221/*
4222 * Main entry point into mballoc to allocate blocks
4223 * it tries to use preallocation first, then falls back
4224 * to usual allocation
4225 */
4226ext4_fsblk_t ext4_mb_new_blocks(handle_t *handle,
4227 struct ext4_allocation_request *ar, int *errp)
4228{
4229 int freed;
4230 struct ext4_allocation_context *ac = NULL;
4231 struct ext4_sb_info *sbi;
4232 struct super_block *sb;
4233 ext4_fsblk_t block = 0;
4234 unsigned int inquota = 0;
4235 unsigned int reserv_clstrs = 0;
4236
4237 sb = ar->inode->i_sb;
4238 sbi = EXT4_SB(sb);
4239
4240 trace_ext4_request_blocks(ar);
4241
4242 /* Allow to use superuser reservation for quota file */
4243 if (IS_NOQUOTA(ar->inode))
4244 ar->flags |= EXT4_MB_USE_ROOT_BLOCKS;
4245
4246 /*
4247 * For delayed allocation, we could skip the ENOSPC and
4248 * EDQUOT check, as blocks and quotas have been already
4249 * reserved when data being copied into pagecache.
4250 */
4251 if (ext4_test_inode_state(ar->inode, EXT4_STATE_DELALLOC_RESERVED))
4252 ar->flags |= EXT4_MB_DELALLOC_RESERVED;
4253 else {
4254 /* Without delayed allocation we need to verify
4255 * there is enough free blocks to do block allocation
4256 * and verify allocation doesn't exceed the quota limits.
4257 */
4258 while (ar->len &&
4259 ext4_claim_free_clusters(sbi, ar->len, ar->flags)) {
4260
4261 /* let others to free the space */
4262 yield();
4263 ar->len = ar->len >> 1;
4264 }
4265 if (!ar->len) {
4266 *errp = -ENOSPC;
4267 return 0;
4268 }
4269 reserv_clstrs = ar->len;
4270 if (ar->flags & EXT4_MB_USE_ROOT_BLOCKS) {
4271 dquot_alloc_block_nofail(ar->inode,
4272 EXT4_C2B(sbi, ar->len));
4273 } else {
4274 while (ar->len &&
4275 dquot_alloc_block(ar->inode,
4276 EXT4_C2B(sbi, ar->len))) {
4277
4278 ar->flags |= EXT4_MB_HINT_NOPREALLOC;
4279 ar->len--;
4280 }
4281 }
4282 inquota = ar->len;
4283 if (ar->len == 0) {
4284 *errp = -EDQUOT;
4285 goto out;
4286 }
4287 }
4288
4289 ac = kmem_cache_alloc(ext4_ac_cachep, GFP_NOFS);
4290 if (!ac) {
4291 ar->len = 0;
4292 *errp = -ENOMEM;
4293 goto out;
4294 }
4295
4296 *errp = ext4_mb_initialize_context(ac, ar);
4297 if (*errp) {
4298 ar->len = 0;
4299 goto out;
4300 }
4301
4302 ac->ac_op = EXT4_MB_HISTORY_PREALLOC;
4303 if (!ext4_mb_use_preallocated(ac)) {
4304 ac->ac_op = EXT4_MB_HISTORY_ALLOC;
4305 ext4_mb_normalize_request(ac, ar);
4306repeat:
4307 /* allocate space in core */
4308 *errp = ext4_mb_regular_allocator(ac);
4309 if (*errp)
4310 goto errout;
4311
4312 /* as we've just preallocated more space than
4313 * user requested orinally, we store allocated
4314 * space in a special descriptor */
4315 if (ac->ac_status == AC_STATUS_FOUND &&
4316 ac->ac_o_ex.fe_len < ac->ac_b_ex.fe_len)
4317 ext4_mb_new_preallocation(ac);
4318 }
4319 if (likely(ac->ac_status == AC_STATUS_FOUND)) {
4320 *errp = ext4_mb_mark_diskspace_used(ac, handle, reserv_clstrs);
4321 if (*errp == -EAGAIN) {
4322 /*
4323 * drop the reference that we took
4324 * in ext4_mb_use_best_found
4325 */
4326 ext4_mb_release_context(ac);
4327 ac->ac_b_ex.fe_group = 0;
4328 ac->ac_b_ex.fe_start = 0;
4329 ac->ac_b_ex.fe_len = 0;
4330 ac->ac_status = AC_STATUS_CONTINUE;
4331 goto repeat;
4332 } else if (*errp)
4333 errout:
4334 ext4_discard_allocated_blocks(ac);
4335 else {
4336 block = ext4_grp_offs_to_block(sb, &ac->ac_b_ex);
4337 ar->len = ac->ac_b_ex.fe_len;
4338 }
4339 } else {
4340 freed = ext4_mb_discard_preallocations(sb, ac->ac_o_ex.fe_len);
4341 if (freed)
4342 goto repeat;
4343 *errp = -ENOSPC;
4344 }
4345
4346 if (*errp) {
4347 ac->ac_b_ex.fe_len = 0;
4348 ar->len = 0;
4349 ext4_mb_show_ac(ac);
4350 }
4351 ext4_mb_release_context(ac);
4352out:
4353 if (ac)
4354 kmem_cache_free(ext4_ac_cachep, ac);
4355 if (inquota && ar->len < inquota)
4356 dquot_free_block(ar->inode, EXT4_C2B(sbi, inquota - ar->len));
4357 if (!ar->len) {
4358 if (!ext4_test_inode_state(ar->inode,
4359 EXT4_STATE_DELALLOC_RESERVED))
4360 /* release all the reserved blocks if non delalloc */
4361 percpu_counter_sub(&sbi->s_dirtyclusters_counter,
4362 reserv_clstrs);
4363 }
4364
4365 trace_ext4_allocate_blocks(ar, (unsigned long long)block);
4366
4367 return block;
4368}
4369
4370/*
4371 * We can merge two free data extents only if the physical blocks
4372 * are contiguous, AND the extents were freed by the same transaction,
4373 * AND the blocks are associated with the same group.
4374 */
4375static int can_merge(struct ext4_free_data *entry1,
4376 struct ext4_free_data *entry2)
4377{
4378 if ((entry1->efd_tid == entry2->efd_tid) &&
4379 (entry1->efd_group == entry2->efd_group) &&
4380 ((entry1->efd_start_cluster + entry1->efd_count) == entry2->efd_start_cluster))
4381 return 1;
4382 return 0;
4383}
4384
4385static noinline_for_stack int
4386ext4_mb_free_metadata(handle_t *handle, struct ext4_buddy *e4b,
4387 struct ext4_free_data *new_entry)
4388{
4389 ext4_group_t group = e4b->bd_group;
4390 ext4_grpblk_t cluster;
4391 struct ext4_free_data *entry;
4392 struct ext4_group_info *db = e4b->bd_info;
4393 struct super_block *sb = e4b->bd_sb;
4394 struct ext4_sb_info *sbi = EXT4_SB(sb);
4395 struct rb_node **n = &db->bb_free_root.rb_node, *node;
4396 struct rb_node *parent = NULL, *new_node;
4397
4398 BUG_ON(!ext4_handle_valid(handle));
4399 BUG_ON(e4b->bd_bitmap_page == NULL);
4400 BUG_ON(e4b->bd_buddy_page == NULL);
4401
4402 new_node = &new_entry->efd_node;
4403 cluster = new_entry->efd_start_cluster;
4404
4405 if (!*n) {
4406 /* first free block exent. We need to
4407 protect buddy cache from being freed,
4408 * otherwise we'll refresh it from
4409 * on-disk bitmap and lose not-yet-available
4410 * blocks */
4411 page_cache_get(e4b->bd_buddy_page);
4412 page_cache_get(e4b->bd_bitmap_page);
4413 }
4414 while (*n) {
4415 parent = *n;
4416 entry = rb_entry(parent, struct ext4_free_data, efd_node);
4417 if (cluster < entry->efd_start_cluster)
4418 n = &(*n)->rb_left;
4419 else if (cluster >= (entry->efd_start_cluster + entry->efd_count))
4420 n = &(*n)->rb_right;
4421 else {
4422 ext4_grp_locked_error(sb, group, 0,
4423 ext4_group_first_block_no(sb, group) +
4424 EXT4_C2B(sbi, cluster),
4425 "Block already on to-be-freed list");
4426 return 0;
4427 }
4428 }
4429
4430 rb_link_node(new_node, parent, n);
4431 rb_insert_color(new_node, &db->bb_free_root);
4432
4433 /* Now try to see the extent can be merged to left and right */
4434 node = rb_prev(new_node);
4435 if (node) {
4436 entry = rb_entry(node, struct ext4_free_data, efd_node);
4437 if (can_merge(entry, new_entry)) {
4438 new_entry->efd_start_cluster = entry->efd_start_cluster;
4439 new_entry->efd_count += entry->efd_count;
4440 rb_erase(node, &(db->bb_free_root));
4441 ext4_journal_callback_del(handle, &entry->efd_jce);
4442 kmem_cache_free(ext4_free_data_cachep, entry);
4443 }
4444 }
4445
4446 node = rb_next(new_node);
4447 if (node) {
4448 entry = rb_entry(node, struct ext4_free_data, efd_node);
4449 if (can_merge(new_entry, entry)) {
4450 new_entry->efd_count += entry->efd_count;
4451 rb_erase(node, &(db->bb_free_root));
4452 ext4_journal_callback_del(handle, &entry->efd_jce);
4453 kmem_cache_free(ext4_free_data_cachep, entry);
4454 }
4455 }
4456 /* Add the extent to transaction's private list */
4457 ext4_journal_callback_add(handle, ext4_free_data_callback,
4458 &new_entry->efd_jce);
4459 return 0;
4460}
4461
4462/**
4463 * ext4_free_blocks() -- Free given blocks and update quota
4464 * @handle: handle for this transaction
4465 * @inode: inode
4466 * @block: start physical block to free
4467 * @count: number of blocks to count
4468 * @flags: flags used by ext4_free_blocks
4469 */
4470void ext4_free_blocks(handle_t *handle, struct inode *inode,
4471 struct buffer_head *bh, ext4_fsblk_t block,
4472 unsigned long count, int flags)
4473{
4474 struct buffer_head *bitmap_bh = NULL;
4475 struct super_block *sb = inode->i_sb;
4476 struct ext4_group_desc *gdp;
4477 unsigned long freed = 0;
4478 unsigned int overflow;
4479 ext4_grpblk_t bit;
4480 struct buffer_head *gd_bh;
4481 ext4_group_t block_group;
4482 struct ext4_sb_info *sbi;
4483 struct ext4_buddy e4b;
4484 unsigned int count_clusters;
4485 int err = 0;
4486 int ret;
4487
4488 if (bh) {
4489 if (block)
4490 BUG_ON(block != bh->b_blocknr);
4491 else
4492 block = bh->b_blocknr;
4493 }
4494
4495 sbi = EXT4_SB(sb);
4496 if (!(flags & EXT4_FREE_BLOCKS_VALIDATED) &&
4497 !ext4_data_block_valid(sbi, block, count)) {
4498 ext4_error(sb, "Freeing blocks not in datazone - "
4499 "block = %llu, count = %lu", block, count);
4500 goto error_return;
4501 }
4502
4503 ext4_debug("freeing block %llu\n", block);
4504 trace_ext4_free_blocks(inode, block, count, flags);
4505
4506 if (flags & EXT4_FREE_BLOCKS_FORGET) {
4507 struct buffer_head *tbh = bh;
4508 int i;
4509
4510 BUG_ON(bh && (count > 1));
4511
4512 for (i = 0; i < count; i++) {
4513 if (!bh)
4514 tbh = sb_find_get_block(inode->i_sb,
4515 block + i);
4516 if (unlikely(!tbh))
4517 continue;
4518 ext4_forget(handle, flags & EXT4_FREE_BLOCKS_METADATA,
4519 inode, tbh, block + i);
4520 }
4521 }
4522
4523 /*
4524 * We need to make sure we don't reuse the freed block until
4525 * after the transaction is committed, which we can do by
4526 * treating the block as metadata, below. We make an
4527 * exception if the inode is to be written in writeback mode
4528 * since writeback mode has weak data consistency guarantees.
4529 */
4530 if (!ext4_should_writeback_data(inode))
4531 flags |= EXT4_FREE_BLOCKS_METADATA;
4532
4533 /*
4534 * If the extent to be freed does not begin on a cluster
4535 * boundary, we need to deal with partial clusters at the
4536 * beginning and end of the extent. Normally we will free
4537 * blocks at the beginning or the end unless we are explicitly
4538 * requested to avoid doing so.
4539 */
4540 overflow = block & (sbi->s_cluster_ratio - 1);
4541 if (overflow) {
4542 if (flags & EXT4_FREE_BLOCKS_NOFREE_FIRST_CLUSTER) {
4543 overflow = sbi->s_cluster_ratio - overflow;
4544 block += overflow;
4545 if (count > overflow)
4546 count -= overflow;
4547 else
4548 return;
4549 } else {
4550 block -= overflow;
4551 count += overflow;
4552 }
4553 }
4554 overflow = count & (sbi->s_cluster_ratio - 1);
4555 if (overflow) {
4556 if (flags & EXT4_FREE_BLOCKS_NOFREE_LAST_CLUSTER) {
4557 if (count > overflow)
4558 count -= overflow;
4559 else
4560 return;
4561 } else
4562 count += sbi->s_cluster_ratio - overflow;
4563 }
4564
4565do_more:
4566 overflow = 0;
4567 ext4_get_group_no_and_offset(sb, block, &block_group, &bit);
4568
4569 /*
4570 * Check to see if we are freeing blocks across a group
4571 * boundary.
4572 */
4573 if (EXT4_C2B(sbi, bit) + count > EXT4_BLOCKS_PER_GROUP(sb)) {
4574 overflow = EXT4_C2B(sbi, bit) + count -
4575 EXT4_BLOCKS_PER_GROUP(sb);
4576 count -= overflow;
4577 }
4578 count_clusters = EXT4_B2C(sbi, count);
4579 bitmap_bh = ext4_read_block_bitmap(sb, block_group);
4580 if (!bitmap_bh) {
4581 err = -EIO;
4582 goto error_return;
4583 }
4584 gdp = ext4_get_group_desc(sb, block_group, &gd_bh);
4585 if (!gdp) {
4586 err = -EIO;
4587 goto error_return;
4588 }
4589
4590 if (in_range(ext4_block_bitmap(sb, gdp), block, count) ||
4591 in_range(ext4_inode_bitmap(sb, gdp), block, count) ||
4592 in_range(block, ext4_inode_table(sb, gdp),
4593 EXT4_SB(sb)->s_itb_per_group) ||
4594 in_range(block + count - 1, ext4_inode_table(sb, gdp),
4595 EXT4_SB(sb)->s_itb_per_group)) {
4596
4597 ext4_error(sb, "Freeing blocks in system zone - "
4598 "Block = %llu, count = %lu", block, count);
4599 /* err = 0. ext4_std_error should be a no op */
4600 goto error_return;
4601 }
4602
4603 BUFFER_TRACE(bitmap_bh, "getting write access");
4604 err = ext4_journal_get_write_access(handle, bitmap_bh);
4605 if (err)
4606 goto error_return;
4607
4608 /*
4609 * We are about to modify some metadata. Call the journal APIs
4610 * to unshare ->b_data if a currently-committing transaction is
4611 * using it
4612 */
4613 BUFFER_TRACE(gd_bh, "get_write_access");
4614 err = ext4_journal_get_write_access(handle, gd_bh);
4615 if (err)
4616 goto error_return;
4617#ifdef AGGRESSIVE_CHECK
4618 {
4619 int i;
4620 for (i = 0; i < count_clusters; i++)
4621 BUG_ON(!mb_test_bit(bit + i, bitmap_bh->b_data));
4622 }
4623#endif
4624 trace_ext4_mballoc_free(sb, inode, block_group, bit, count_clusters);
4625
4626 err = ext4_mb_load_buddy(sb, block_group, &e4b);
4627 if (err)
4628 goto error_return;
4629
4630 if ((flags & EXT4_FREE_BLOCKS_METADATA) && ext4_handle_valid(handle)) {
4631 struct ext4_free_data *new_entry;
4632 /*
4633 * blocks being freed are metadata. these blocks shouldn't
4634 * be used until this transaction is committed
4635 */
4636 new_entry = kmem_cache_alloc(ext4_free_data_cachep, GFP_NOFS);
4637 if (!new_entry) {
4638 ext4_mb_unload_buddy(&e4b);
4639 err = -ENOMEM;
4640 goto error_return;
4641 }
4642 new_entry->efd_start_cluster = bit;
4643 new_entry->efd_group = block_group;
4644 new_entry->efd_count = count_clusters;
4645 new_entry->efd_tid = handle->h_transaction->t_tid;
4646
4647 ext4_lock_group(sb, block_group);
4648 mb_clear_bits(bitmap_bh->b_data, bit, count_clusters);
4649 ext4_mb_free_metadata(handle, &e4b, new_entry);
4650 } else {
4651 /* need to update group_info->bb_free and bitmap
4652 * with group lock held. generate_buddy look at
4653 * them with group lock_held
4654 */
4655 ext4_lock_group(sb, block_group);
4656 mb_clear_bits(bitmap_bh->b_data, bit, count_clusters);
4657 mb_free_blocks(inode, &e4b, bit, count_clusters);
4658 }
4659
4660 ret = ext4_free_group_clusters(sb, gdp) + count_clusters;
4661 ext4_free_group_clusters_set(sb, gdp, ret);
4662 ext4_block_bitmap_csum_set(sb, block_group, gdp, bitmap_bh,
4663 EXT4_BLOCKS_PER_GROUP(sb) / 8);
4664 ext4_group_desc_csum_set(sb, block_group, gdp);
4665 ext4_unlock_group(sb, block_group);
4666 percpu_counter_add(&sbi->s_freeclusters_counter, count_clusters);
4667
4668 if (sbi->s_log_groups_per_flex) {
4669 ext4_group_t flex_group = ext4_flex_group(sbi, block_group);
4670 atomic_add(count_clusters,
4671 &sbi->s_flex_groups[flex_group].free_clusters);
4672 }
4673
4674 ext4_mb_unload_buddy(&e4b);
4675
4676 freed += count;
4677
4678 if (!(flags & EXT4_FREE_BLOCKS_NO_QUOT_UPDATE))
4679 dquot_free_block(inode, EXT4_C2B(sbi, count_clusters));
4680
4681 /* We dirtied the bitmap block */
4682 BUFFER_TRACE(bitmap_bh, "dirtied bitmap block");
4683 err = ext4_handle_dirty_metadata(handle, NULL, bitmap_bh);
4684
4685 /* And the group descriptor block */
4686 BUFFER_TRACE(gd_bh, "dirtied group descriptor block");
4687 ret = ext4_handle_dirty_metadata(handle, NULL, gd_bh);
4688 if (!err)
4689 err = ret;
4690
4691 if (overflow && !err) {
4692 block += count;
4693 count = overflow;
4694 put_bh(bitmap_bh);
4695 goto do_more;
4696 }
4697 ext4_mark_super_dirty(sb);
4698error_return:
4699 brelse(bitmap_bh);
4700 ext4_std_error(sb, err);
4701 return;
4702}
4703
4704/**
4705 * ext4_group_add_blocks() -- Add given blocks to an existing group
4706 * @handle: handle to this transaction
4707 * @sb: super block
4708 * @block: start physcial block to add to the block group
4709 * @count: number of blocks to free
4710 *
4711 * This marks the blocks as free in the bitmap and buddy.
4712 */
4713int ext4_group_add_blocks(handle_t *handle, struct super_block *sb,
4714 ext4_fsblk_t block, unsigned long count)
4715{
4716 struct buffer_head *bitmap_bh = NULL;
4717 struct buffer_head *gd_bh;
4718 ext4_group_t block_group;
4719 ext4_grpblk_t bit;
4720 unsigned int i;
4721 struct ext4_group_desc *desc;
4722 struct ext4_sb_info *sbi = EXT4_SB(sb);
4723 struct ext4_buddy e4b;
4724 int err = 0, ret, blk_free_count;
4725 ext4_grpblk_t blocks_freed;
4726
4727 ext4_debug("Adding block(s) %llu-%llu\n", block, block + count - 1);
4728
4729 if (count == 0)
4730 return 0;
4731
4732 ext4_get_group_no_and_offset(sb, block, &block_group, &bit);
4733 /*
4734 * Check to see if we are freeing blocks across a group
4735 * boundary.
4736 */
4737 if (bit + count > EXT4_BLOCKS_PER_GROUP(sb)) {
4738 ext4_warning(sb, "too much blocks added to group %u\n",
4739 block_group);
4740 err = -EINVAL;
4741 goto error_return;
4742 }
4743
4744 bitmap_bh = ext4_read_block_bitmap(sb, block_group);
4745 if (!bitmap_bh) {
4746 err = -EIO;
4747 goto error_return;
4748 }
4749
4750 desc = ext4_get_group_desc(sb, block_group, &gd_bh);
4751 if (!desc) {
4752 err = -EIO;
4753 goto error_return;
4754 }
4755
4756 if (in_range(ext4_block_bitmap(sb, desc), block, count) ||
4757 in_range(ext4_inode_bitmap(sb, desc), block, count) ||
4758 in_range(block, ext4_inode_table(sb, desc), sbi->s_itb_per_group) ||
4759 in_range(block + count - 1, ext4_inode_table(sb, desc),
4760 sbi->s_itb_per_group)) {
4761 ext4_error(sb, "Adding blocks in system zones - "
4762 "Block = %llu, count = %lu",
4763 block, count);
4764 err = -EINVAL;
4765 goto error_return;
4766 }
4767
4768 BUFFER_TRACE(bitmap_bh, "getting write access");
4769 err = ext4_journal_get_write_access(handle, bitmap_bh);
4770 if (err)
4771 goto error_return;
4772
4773 /*
4774 * We are about to modify some metadata. Call the journal APIs
4775 * to unshare ->b_data if a currently-committing transaction is
4776 * using it
4777 */
4778 BUFFER_TRACE(gd_bh, "get_write_access");
4779 err = ext4_journal_get_write_access(handle, gd_bh);
4780 if (err)
4781 goto error_return;
4782
4783 for (i = 0, blocks_freed = 0; i < count; i++) {
4784 BUFFER_TRACE(bitmap_bh, "clear bit");
4785 if (!mb_test_bit(bit + i, bitmap_bh->b_data)) {
4786 ext4_error(sb, "bit already cleared for block %llu",
4787 (ext4_fsblk_t)(block + i));
4788 BUFFER_TRACE(bitmap_bh, "bit already cleared");
4789 } else {
4790 blocks_freed++;
4791 }
4792 }
4793
4794 err = ext4_mb_load_buddy(sb, block_group, &e4b);
4795 if (err)
4796 goto error_return;
4797
4798 /*
4799 * need to update group_info->bb_free and bitmap
4800 * with group lock held. generate_buddy look at
4801 * them with group lock_held
4802 */
4803 ext4_lock_group(sb, block_group);
4804 mb_clear_bits(bitmap_bh->b_data, bit, count);
4805 mb_free_blocks(NULL, &e4b, bit, count);
4806 blk_free_count = blocks_freed + ext4_free_group_clusters(sb, desc);
4807 ext4_free_group_clusters_set(sb, desc, blk_free_count);
4808 ext4_block_bitmap_csum_set(sb, block_group, desc, bitmap_bh,
4809 EXT4_BLOCKS_PER_GROUP(sb) / 8);
4810 ext4_group_desc_csum_set(sb, block_group, desc);
4811 ext4_unlock_group(sb, block_group);
4812 percpu_counter_add(&sbi->s_freeclusters_counter,
4813 EXT4_B2C(sbi, blocks_freed));
4814
4815 if (sbi->s_log_groups_per_flex) {
4816 ext4_group_t flex_group = ext4_flex_group(sbi, block_group);
4817 atomic_add(EXT4_B2C(sbi, blocks_freed),
4818 &sbi->s_flex_groups[flex_group].free_clusters);
4819 }
4820
4821 ext4_mb_unload_buddy(&e4b);
4822
4823 /* We dirtied the bitmap block */
4824 BUFFER_TRACE(bitmap_bh, "dirtied bitmap block");
4825 err = ext4_handle_dirty_metadata(handle, NULL, bitmap_bh);
4826
4827 /* And the group descriptor block */
4828 BUFFER_TRACE(gd_bh, "dirtied group descriptor block");
4829 ret = ext4_handle_dirty_metadata(handle, NULL, gd_bh);
4830 if (!err)
4831 err = ret;
4832
4833error_return:
4834 brelse(bitmap_bh);
4835 ext4_std_error(sb, err);
4836 return err;
4837}
4838
4839/**
4840 * ext4_trim_extent -- function to TRIM one single free extent in the group
4841 * @sb: super block for the file system
4842 * @start: starting block of the free extent in the alloc. group
4843 * @count: number of blocks to TRIM
4844 * @group: alloc. group we are working with
4845 * @e4b: ext4 buddy for the group
4846 *
4847 * Trim "count" blocks starting at "start" in the "group". To assure that no
4848 * one will allocate those blocks, mark it as used in buddy bitmap. This must
4849 * be called with under the group lock.
4850 */
4851static void ext4_trim_extent(struct super_block *sb, int start, int count,
4852 ext4_group_t group, struct ext4_buddy *e4b)
4853{
4854 struct ext4_free_extent ex;
4855
4856 trace_ext4_trim_extent(sb, group, start, count);
4857
4858 assert_spin_locked(ext4_group_lock_ptr(sb, group));
4859
4860 ex.fe_start = start;
4861 ex.fe_group = group;
4862 ex.fe_len = count;
4863
4864 /*
4865 * Mark blocks used, so no one can reuse them while
4866 * being trimmed.
4867 */
4868 mb_mark_used(e4b, &ex);
4869 ext4_unlock_group(sb, group);
4870 ext4_issue_discard(sb, group, start, count);
4871 ext4_lock_group(sb, group);
4872 mb_free_blocks(NULL, e4b, start, ex.fe_len);
4873}
4874
4875/**
4876 * ext4_trim_all_free -- function to trim all free space in alloc. group
4877 * @sb: super block for file system
4878 * @group: group to be trimmed
4879 * @start: first group block to examine
4880 * @max: last group block to examine
4881 * @minblocks: minimum extent block count
4882 *
4883 * ext4_trim_all_free walks through group's buddy bitmap searching for free
4884 * extents. When the free block is found, ext4_trim_extent is called to TRIM
4885 * the extent.
4886 *
4887 *
4888 * ext4_trim_all_free walks through group's block bitmap searching for free
4889 * extents. When the free extent is found, mark it as used in group buddy
4890 * bitmap. Then issue a TRIM command on this extent and free the extent in
4891 * the group buddy bitmap. This is done until whole group is scanned.
4892 */
4893static ext4_grpblk_t
4894ext4_trim_all_free(struct super_block *sb, ext4_group_t group,
4895 ext4_grpblk_t start, ext4_grpblk_t max,
4896 ext4_grpblk_t minblocks)
4897{
4898 void *bitmap;
4899 ext4_grpblk_t next, count = 0, free_count = 0;
4900 struct ext4_buddy e4b;
4901 int ret;
4902
4903 trace_ext4_trim_all_free(sb, group, start, max);
4904
4905 ret = ext4_mb_load_buddy(sb, group, &e4b);
4906 if (ret) {
4907 ext4_error(sb, "Error in loading buddy "
4908 "information for %u", group);
4909 return ret;
4910 }
4911 bitmap = e4b.bd_bitmap;
4912
4913 ext4_lock_group(sb, group);
4914 if (EXT4_MB_GRP_WAS_TRIMMED(e4b.bd_info) &&
4915 minblocks >= atomic_read(&EXT4_SB(sb)->s_last_trim_minblks))
4916 goto out;
4917
4918 start = (e4b.bd_info->bb_first_free > start) ?
4919 e4b.bd_info->bb_first_free : start;
4920
4921 while (start <= max) {
4922 start = mb_find_next_zero_bit(bitmap, max + 1, start);
4923 if (start > max)
4924 break;
4925 next = mb_find_next_bit(bitmap, max + 1, start);
4926
4927 if ((next - start) >= minblocks) {
4928 ext4_trim_extent(sb, start,
4929 next - start, group, &e4b);
4930 count += next - start;
4931 }
4932 free_count += next - start;
4933 start = next + 1;
4934
4935 if (fatal_signal_pending(current)) {
4936 count = -ERESTARTSYS;
4937 break;
4938 }
4939
4940 if (need_resched()) {
4941 ext4_unlock_group(sb, group);
4942 cond_resched();
4943 ext4_lock_group(sb, group);
4944 }
4945
4946 if ((e4b.bd_info->bb_free - free_count) < minblocks)
4947 break;
4948 }
4949
4950 if (!ret)
4951 EXT4_MB_GRP_SET_TRIMMED(e4b.bd_info);
4952out:
4953 ext4_unlock_group(sb, group);
4954 ext4_mb_unload_buddy(&e4b);
4955
4956 ext4_debug("trimmed %d blocks in the group %d\n",
4957 count, group);
4958
4959 return count;
4960}
4961
4962/**
4963 * ext4_trim_fs() -- trim ioctl handle function
4964 * @sb: superblock for filesystem
4965 * @range: fstrim_range structure
4966 *
4967 * start: First Byte to trim
4968 * len: number of Bytes to trim from start
4969 * minlen: minimum extent length in Bytes
4970 * ext4_trim_fs goes through all allocation groups containing Bytes from
4971 * start to start+len. For each such a group ext4_trim_all_free function
4972 * is invoked to trim all free space.
4973 */
4974int ext4_trim_fs(struct super_block *sb, struct fstrim_range *range)
4975{
4976 struct ext4_group_info *grp;
4977 ext4_group_t group, first_group, last_group;
4978 ext4_grpblk_t cnt = 0, first_cluster, last_cluster;
4979 uint64_t start, end, minlen, trimmed = 0;
4980 ext4_fsblk_t first_data_blk =
4981 le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block);
4982 ext4_fsblk_t max_blks = ext4_blocks_count(EXT4_SB(sb)->s_es);
4983 int ret = 0;
4984
4985 start = range->start >> sb->s_blocksize_bits;
4986 end = start + (range->len >> sb->s_blocksize_bits) - 1;
4987 minlen = range->minlen >> sb->s_blocksize_bits;
4988
4989 if (unlikely(minlen > EXT4_CLUSTERS_PER_GROUP(sb)) ||
4990 unlikely(start >= max_blks))
4991 return -EINVAL;
4992 if (end >= max_blks)
4993 end = max_blks - 1;
4994 if (end <= first_data_blk)
4995 goto out;
4996 if (start < first_data_blk)
4997 start = first_data_blk;
4998
4999 /* Determine first and last group to examine based on start and end */
5000 ext4_get_group_no_and_offset(sb, (ext4_fsblk_t) start,
5001 &first_group, &first_cluster);
5002 ext4_get_group_no_and_offset(sb, (ext4_fsblk_t) end,
5003 &last_group, &last_cluster);
5004
5005 /* end now represents the last cluster to discard in this group */
5006 end = EXT4_CLUSTERS_PER_GROUP(sb) - 1;
5007
5008 for (group = first_group; group <= last_group; group++) {
5009 grp = ext4_get_group_info(sb, group);
5010 /* We only do this if the grp has never been initialized */
5011 if (unlikely(EXT4_MB_GRP_NEED_INIT(grp))) {
5012 ret = ext4_mb_init_group(sb, group);
5013 if (ret)
5014 break;
5015 }
5016
5017 /*
5018 * For all the groups except the last one, last cluster will
5019 * always be EXT4_CLUSTERS_PER_GROUP(sb)-1, so we only need to
5020 * change it for the last group, note that last_cluster is
5021 * already computed earlier by ext4_get_group_no_and_offset()
5022 */
5023 if (group == last_group)
5024 end = last_cluster;
5025
5026 if (grp->bb_free >= minlen) {
5027 cnt = ext4_trim_all_free(sb, group, first_cluster,
5028 end, minlen);
5029 if (cnt < 0) {
5030 ret = cnt;
5031 break;
5032 }
5033 trimmed += cnt;
5034 }
5035
5036 /*
5037 * For every group except the first one, we are sure
5038 * that the first cluster to discard will be cluster #0.
5039 */
5040 first_cluster = 0;
5041 }
5042
5043 if (!ret)
5044 atomic_set(&EXT4_SB(sb)->s_last_trim_minblks, minlen);
5045
5046out:
5047 range->len = trimmed * sb->s_blocksize;
5048 return ret;
5049}
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}