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1/*
2 * linux/fs/ext4/balloc.c
3 *
4 * Copyright (C) 1992, 1993, 1994, 1995
5 * Remy Card (card@masi.ibp.fr)
6 * Laboratoire MASI - Institut Blaise Pascal
7 * Universite Pierre et Marie Curie (Paris VI)
8 *
9 * Enhanced block allocation by Stephen Tweedie (sct@redhat.com), 1993
10 * Big-endian to little-endian byte-swapping/bitmaps by
11 * David S. Miller (davem@caip.rutgers.edu), 1995
12 */
13
14#include <linux/time.h>
15#include <linux/capability.h>
16#include <linux/fs.h>
17#include <linux/jbd2.h>
18#include <linux/quotaops.h>
19#include <linux/buffer_head.h>
20#include "ext4.h"
21#include "ext4_jbd2.h"
22#include "mballoc.h"
23
24#include <trace/events/ext4.h>
25
26static unsigned ext4_num_base_meta_clusters(struct super_block *sb,
27 ext4_group_t block_group);
28/*
29 * balloc.c contains the blocks allocation and deallocation routines
30 */
31
32/*
33 * Calculate block group number for a given block number
34 */
35ext4_group_t ext4_get_group_number(struct super_block *sb,
36 ext4_fsblk_t block)
37{
38 ext4_group_t group;
39
40 if (test_opt2(sb, STD_GROUP_SIZE))
41 group = (block -
42 le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block)) >>
43 (EXT4_BLOCK_SIZE_BITS(sb) + EXT4_CLUSTER_BITS(sb) + 3);
44 else
45 ext4_get_group_no_and_offset(sb, block, &group, NULL);
46 return group;
47}
48
49/*
50 * Calculate the block group number and offset into the block/cluster
51 * allocation bitmap, given a block number
52 */
53void ext4_get_group_no_and_offset(struct super_block *sb, ext4_fsblk_t blocknr,
54 ext4_group_t *blockgrpp, ext4_grpblk_t *offsetp)
55{
56 struct ext4_super_block *es = EXT4_SB(sb)->s_es;
57 ext4_grpblk_t offset;
58
59 blocknr = blocknr - le32_to_cpu(es->s_first_data_block);
60 offset = do_div(blocknr, EXT4_BLOCKS_PER_GROUP(sb)) >>
61 EXT4_SB(sb)->s_cluster_bits;
62 if (offsetp)
63 *offsetp = offset;
64 if (blockgrpp)
65 *blockgrpp = blocknr;
66
67}
68
69/*
70 * Check whether the 'block' lives within the 'block_group'. Returns 1 if so
71 * and 0 otherwise.
72 */
73static inline int ext4_block_in_group(struct super_block *sb,
74 ext4_fsblk_t block,
75 ext4_group_t block_group)
76{
77 ext4_group_t actual_group;
78
79 actual_group = ext4_get_group_number(sb, block);
80 return (actual_group == block_group) ? 1 : 0;
81}
82
83/* Return the number of clusters used for file system metadata; this
84 * represents the overhead needed by the file system.
85 */
86unsigned ext4_num_overhead_clusters(struct super_block *sb,
87 ext4_group_t block_group,
88 struct ext4_group_desc *gdp)
89{
90 unsigned num_clusters;
91 int block_cluster = -1, inode_cluster = -1, itbl_cluster = -1, i, c;
92 ext4_fsblk_t start = ext4_group_first_block_no(sb, block_group);
93 ext4_fsblk_t itbl_blk;
94 struct ext4_sb_info *sbi = EXT4_SB(sb);
95
96 /* This is the number of clusters used by the superblock,
97 * block group descriptors, and reserved block group
98 * descriptor blocks */
99 num_clusters = ext4_num_base_meta_clusters(sb, block_group);
100
101 /*
102 * For the allocation bitmaps and inode table, we first need
103 * to check to see if the block is in the block group. If it
104 * is, then check to see if the cluster is already accounted
105 * for in the clusters used for the base metadata cluster, or
106 * if we can increment the base metadata cluster to include
107 * that block. Otherwise, we will have to track the cluster
108 * used for the allocation bitmap or inode table explicitly.
109 * Normally all of these blocks are contiguous, so the special
110 * case handling shouldn't be necessary except for *very*
111 * unusual file system layouts.
112 */
113 if (ext4_block_in_group(sb, ext4_block_bitmap(sb, gdp), block_group)) {
114 block_cluster = EXT4_B2C(sbi,
115 ext4_block_bitmap(sb, gdp) - start);
116 if (block_cluster < num_clusters)
117 block_cluster = -1;
118 else if (block_cluster == num_clusters) {
119 num_clusters++;
120 block_cluster = -1;
121 }
122 }
123
124 if (ext4_block_in_group(sb, ext4_inode_bitmap(sb, gdp), block_group)) {
125 inode_cluster = EXT4_B2C(sbi,
126 ext4_inode_bitmap(sb, gdp) - start);
127 if (inode_cluster < num_clusters)
128 inode_cluster = -1;
129 else if (inode_cluster == num_clusters) {
130 num_clusters++;
131 inode_cluster = -1;
132 }
133 }
134
135 itbl_blk = ext4_inode_table(sb, gdp);
136 for (i = 0; i < sbi->s_itb_per_group; i++) {
137 if (ext4_block_in_group(sb, itbl_blk + i, block_group)) {
138 c = EXT4_B2C(sbi, itbl_blk + i - start);
139 if ((c < num_clusters) || (c == inode_cluster) ||
140 (c == block_cluster) || (c == itbl_cluster))
141 continue;
142 if (c == num_clusters) {
143 num_clusters++;
144 continue;
145 }
146 num_clusters++;
147 itbl_cluster = c;
148 }
149 }
150
151 if (block_cluster != -1)
152 num_clusters++;
153 if (inode_cluster != -1)
154 num_clusters++;
155
156 return num_clusters;
157}
158
159static unsigned int num_clusters_in_group(struct super_block *sb,
160 ext4_group_t block_group)
161{
162 unsigned int blocks;
163
164 if (block_group == ext4_get_groups_count(sb) - 1) {
165 /*
166 * Even though mke2fs always initializes the first and
167 * last group, just in case some other tool was used,
168 * we need to make sure we calculate the right free
169 * blocks.
170 */
171 blocks = ext4_blocks_count(EXT4_SB(sb)->s_es) -
172 ext4_group_first_block_no(sb, block_group);
173 } else
174 blocks = EXT4_BLOCKS_PER_GROUP(sb);
175 return EXT4_NUM_B2C(EXT4_SB(sb), blocks);
176}
177
178/* Initializes an uninitialized block bitmap */
179void ext4_init_block_bitmap(struct super_block *sb, struct buffer_head *bh,
180 ext4_group_t block_group,
181 struct ext4_group_desc *gdp)
182{
183 unsigned int bit, bit_max;
184 struct ext4_sb_info *sbi = EXT4_SB(sb);
185 ext4_fsblk_t start, tmp;
186 int flex_bg = 0;
187 struct ext4_group_info *grp;
188
189 J_ASSERT_BH(bh, buffer_locked(bh));
190
191 /* If checksum is bad mark all blocks used to prevent allocation
192 * essentially implementing a per-group read-only flag. */
193 if (!ext4_group_desc_csum_verify(sb, block_group, gdp)) {
194 ext4_error(sb, "Checksum bad for group %u", block_group);
195 grp = ext4_get_group_info(sb, block_group);
196 set_bit(EXT4_GROUP_INFO_BBITMAP_CORRUPT_BIT, &grp->bb_state);
197 set_bit(EXT4_GROUP_INFO_IBITMAP_CORRUPT_BIT, &grp->bb_state);
198 return;
199 }
200 memset(bh->b_data, 0, sb->s_blocksize);
201
202 bit_max = ext4_num_base_meta_clusters(sb, block_group);
203 for (bit = 0; bit < bit_max; bit++)
204 ext4_set_bit(bit, bh->b_data);
205
206 start = ext4_group_first_block_no(sb, block_group);
207
208 if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_FLEX_BG))
209 flex_bg = 1;
210
211 /* Set bits for block and inode bitmaps, and inode table */
212 tmp = ext4_block_bitmap(sb, gdp);
213 if (!flex_bg || ext4_block_in_group(sb, tmp, block_group))
214 ext4_set_bit(EXT4_B2C(sbi, tmp - start), bh->b_data);
215
216 tmp = ext4_inode_bitmap(sb, gdp);
217 if (!flex_bg || ext4_block_in_group(sb, tmp, block_group))
218 ext4_set_bit(EXT4_B2C(sbi, tmp - start), bh->b_data);
219
220 tmp = ext4_inode_table(sb, gdp);
221 for (; tmp < ext4_inode_table(sb, gdp) +
222 sbi->s_itb_per_group; tmp++) {
223 if (!flex_bg || ext4_block_in_group(sb, tmp, block_group))
224 ext4_set_bit(EXT4_B2C(sbi, tmp - start), bh->b_data);
225 }
226
227 /*
228 * Also if the number of blocks within the group is less than
229 * the blocksize * 8 ( which is the size of bitmap ), set rest
230 * of the block bitmap to 1
231 */
232 ext4_mark_bitmap_end(num_clusters_in_group(sb, block_group),
233 sb->s_blocksize * 8, bh->b_data);
234 ext4_block_bitmap_csum_set(sb, block_group, gdp, bh);
235 ext4_group_desc_csum_set(sb, block_group, gdp);
236}
237
238/* Return the number of free blocks in a block group. It is used when
239 * the block bitmap is uninitialized, so we can't just count the bits
240 * in the bitmap. */
241unsigned ext4_free_clusters_after_init(struct super_block *sb,
242 ext4_group_t block_group,
243 struct ext4_group_desc *gdp)
244{
245 return num_clusters_in_group(sb, block_group) -
246 ext4_num_overhead_clusters(sb, block_group, gdp);
247}
248
249/*
250 * The free blocks are managed by bitmaps. A file system contains several
251 * blocks groups. Each group contains 1 bitmap block for blocks, 1 bitmap
252 * block for inodes, N blocks for the inode table and data blocks.
253 *
254 * The file system contains group descriptors which are located after the
255 * super block. Each descriptor contains the number of the bitmap block and
256 * the free blocks count in the block. The descriptors are loaded in memory
257 * when a file system is mounted (see ext4_fill_super).
258 */
259
260/**
261 * ext4_get_group_desc() -- load group descriptor from disk
262 * @sb: super block
263 * @block_group: given block group
264 * @bh: pointer to the buffer head to store the block
265 * group descriptor
266 */
267struct ext4_group_desc * ext4_get_group_desc(struct super_block *sb,
268 ext4_group_t block_group,
269 struct buffer_head **bh)
270{
271 unsigned int group_desc;
272 unsigned int offset;
273 ext4_group_t ngroups = ext4_get_groups_count(sb);
274 struct ext4_group_desc *desc;
275 struct ext4_sb_info *sbi = EXT4_SB(sb);
276
277 if (block_group >= ngroups) {
278 ext4_error(sb, "block_group >= groups_count - block_group = %u,"
279 " groups_count = %u", block_group, ngroups);
280
281 return NULL;
282 }
283
284 group_desc = block_group >> EXT4_DESC_PER_BLOCK_BITS(sb);
285 offset = block_group & (EXT4_DESC_PER_BLOCK(sb) - 1);
286 if (!sbi->s_group_desc[group_desc]) {
287 ext4_error(sb, "Group descriptor not loaded - "
288 "block_group = %u, group_desc = %u, desc = %u",
289 block_group, group_desc, offset);
290 return NULL;
291 }
292
293 desc = (struct ext4_group_desc *)(
294 (__u8 *)sbi->s_group_desc[group_desc]->b_data +
295 offset * EXT4_DESC_SIZE(sb));
296 if (bh)
297 *bh = sbi->s_group_desc[group_desc];
298 return desc;
299}
300
301/*
302 * Return the block number which was discovered to be invalid, or 0 if
303 * the block bitmap is valid.
304 */
305static ext4_fsblk_t ext4_valid_block_bitmap(struct super_block *sb,
306 struct ext4_group_desc *desc,
307 ext4_group_t block_group,
308 struct buffer_head *bh)
309{
310 ext4_grpblk_t offset;
311 ext4_grpblk_t next_zero_bit;
312 ext4_fsblk_t blk;
313 ext4_fsblk_t group_first_block;
314
315 if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_FLEX_BG)) {
316 /* with FLEX_BG, the inode/block bitmaps and itable
317 * blocks may not be in the group at all
318 * so the bitmap validation will be skipped for those groups
319 * or it has to also read the block group where the bitmaps
320 * are located to verify they are set.
321 */
322 return 0;
323 }
324 group_first_block = ext4_group_first_block_no(sb, block_group);
325
326 /* check whether block bitmap block number is set */
327 blk = ext4_block_bitmap(sb, desc);
328 offset = blk - group_first_block;
329 if (!ext4_test_bit(offset, bh->b_data))
330 /* bad block bitmap */
331 return blk;
332
333 /* check whether the inode bitmap block number is set */
334 blk = ext4_inode_bitmap(sb, desc);
335 offset = blk - group_first_block;
336 if (!ext4_test_bit(offset, bh->b_data))
337 /* bad block bitmap */
338 return blk;
339
340 /* check whether the inode table block number is set */
341 blk = ext4_inode_table(sb, desc);
342 offset = blk - group_first_block;
343 next_zero_bit = ext4_find_next_zero_bit(bh->b_data,
344 offset + EXT4_SB(sb)->s_itb_per_group,
345 offset);
346 if (next_zero_bit < offset + EXT4_SB(sb)->s_itb_per_group)
347 /* bad bitmap for inode tables */
348 return blk;
349 return 0;
350}
351
352void ext4_validate_block_bitmap(struct super_block *sb,
353 struct ext4_group_desc *desc,
354 ext4_group_t block_group,
355 struct buffer_head *bh)
356{
357 ext4_fsblk_t blk;
358 struct ext4_group_info *grp = ext4_get_group_info(sb, block_group);
359
360 if (buffer_verified(bh))
361 return;
362
363 ext4_lock_group(sb, block_group);
364 blk = ext4_valid_block_bitmap(sb, desc, block_group, bh);
365 if (unlikely(blk != 0)) {
366 ext4_unlock_group(sb, block_group);
367 ext4_error(sb, "bg %u: block %llu: invalid block bitmap",
368 block_group, blk);
369 set_bit(EXT4_GROUP_INFO_BBITMAP_CORRUPT_BIT, &grp->bb_state);
370 return;
371 }
372 if (unlikely(!ext4_block_bitmap_csum_verify(sb, block_group,
373 desc, bh))) {
374 ext4_unlock_group(sb, block_group);
375 ext4_error(sb, "bg %u: bad block bitmap checksum", block_group);
376 set_bit(EXT4_GROUP_INFO_BBITMAP_CORRUPT_BIT, &grp->bb_state);
377 return;
378 }
379 set_buffer_verified(bh);
380 ext4_unlock_group(sb, block_group);
381}
382
383/**
384 * ext4_read_block_bitmap_nowait()
385 * @sb: super block
386 * @block_group: given block group
387 *
388 * Read the bitmap for a given block_group,and validate the
389 * bits for block/inode/inode tables are set in the bitmaps
390 *
391 * Return buffer_head on success or NULL in case of failure.
392 */
393struct buffer_head *
394ext4_read_block_bitmap_nowait(struct super_block *sb, ext4_group_t block_group)
395{
396 struct ext4_group_desc *desc;
397 struct buffer_head *bh;
398 ext4_fsblk_t bitmap_blk;
399
400 desc = ext4_get_group_desc(sb, block_group, NULL);
401 if (!desc)
402 return NULL;
403 bitmap_blk = ext4_block_bitmap(sb, desc);
404 bh = sb_getblk(sb, bitmap_blk);
405 if (unlikely(!bh)) {
406 ext4_error(sb, "Cannot get buffer for block bitmap - "
407 "block_group = %u, block_bitmap = %llu",
408 block_group, bitmap_blk);
409 return NULL;
410 }
411
412 if (bitmap_uptodate(bh))
413 goto verify;
414
415 lock_buffer(bh);
416 if (bitmap_uptodate(bh)) {
417 unlock_buffer(bh);
418 goto verify;
419 }
420 ext4_lock_group(sb, block_group);
421 if (desc->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) {
422 ext4_init_block_bitmap(sb, bh, block_group, desc);
423 set_bitmap_uptodate(bh);
424 set_buffer_uptodate(bh);
425 ext4_unlock_group(sb, block_group);
426 unlock_buffer(bh);
427 return bh;
428 }
429 ext4_unlock_group(sb, block_group);
430 if (buffer_uptodate(bh)) {
431 /*
432 * if not uninit if bh is uptodate,
433 * bitmap is also uptodate
434 */
435 set_bitmap_uptodate(bh);
436 unlock_buffer(bh);
437 goto verify;
438 }
439 /*
440 * submit the buffer_head for reading
441 */
442 set_buffer_new(bh);
443 trace_ext4_read_block_bitmap_load(sb, block_group);
444 bh->b_end_io = ext4_end_bitmap_read;
445 get_bh(bh);
446 submit_bh(READ | REQ_META | REQ_PRIO, bh);
447 return bh;
448verify:
449 ext4_validate_block_bitmap(sb, desc, block_group, bh);
450 if (buffer_verified(bh))
451 return bh;
452 put_bh(bh);
453 return NULL;
454}
455
456/* Returns 0 on success, 1 on error */
457int ext4_wait_block_bitmap(struct super_block *sb, ext4_group_t block_group,
458 struct buffer_head *bh)
459{
460 struct ext4_group_desc *desc;
461
462 if (!buffer_new(bh))
463 return 0;
464 desc = ext4_get_group_desc(sb, block_group, NULL);
465 if (!desc)
466 return 1;
467 wait_on_buffer(bh);
468 if (!buffer_uptodate(bh)) {
469 ext4_error(sb, "Cannot read block bitmap - "
470 "block_group = %u, block_bitmap = %llu",
471 block_group, (unsigned long long) bh->b_blocknr);
472 return 1;
473 }
474 clear_buffer_new(bh);
475 /* Panic or remount fs read-only if block bitmap is invalid */
476 ext4_validate_block_bitmap(sb, desc, block_group, bh);
477 /* ...but check for error just in case errors=continue. */
478 return !buffer_verified(bh);
479}
480
481struct buffer_head *
482ext4_read_block_bitmap(struct super_block *sb, ext4_group_t block_group)
483{
484 struct buffer_head *bh;
485
486 bh = ext4_read_block_bitmap_nowait(sb, block_group);
487 if (!bh)
488 return NULL;
489 if (ext4_wait_block_bitmap(sb, block_group, bh)) {
490 put_bh(bh);
491 return NULL;
492 }
493 return bh;
494}
495
496/**
497 * ext4_has_free_clusters()
498 * @sbi: in-core super block structure.
499 * @nclusters: number of needed blocks
500 * @flags: flags from ext4_mb_new_blocks()
501 *
502 * Check if filesystem has nclusters free & available for allocation.
503 * On success return 1, return 0 on failure.
504 */
505static int ext4_has_free_clusters(struct ext4_sb_info *sbi,
506 s64 nclusters, unsigned int flags)
507{
508 s64 free_clusters, dirty_clusters, rsv, resv_clusters;
509 struct percpu_counter *fcc = &sbi->s_freeclusters_counter;
510 struct percpu_counter *dcc = &sbi->s_dirtyclusters_counter;
511
512 free_clusters = percpu_counter_read_positive(fcc);
513 dirty_clusters = percpu_counter_read_positive(dcc);
514 resv_clusters = atomic64_read(&sbi->s_resv_clusters);
515
516 /*
517 * r_blocks_count should always be multiple of the cluster ratio so
518 * we are safe to do a plane bit shift only.
519 */
520 rsv = (ext4_r_blocks_count(sbi->s_es) >> sbi->s_cluster_bits) +
521 resv_clusters;
522
523 if (free_clusters - (nclusters + rsv + dirty_clusters) <
524 EXT4_FREECLUSTERS_WATERMARK) {
525 free_clusters = percpu_counter_sum_positive(fcc);
526 dirty_clusters = percpu_counter_sum_positive(dcc);
527 }
528 /* Check whether we have space after accounting for current
529 * dirty clusters & root reserved clusters.
530 */
531 if (free_clusters >= (rsv + nclusters + dirty_clusters))
532 return 1;
533
534 /* Hm, nope. Are (enough) root reserved clusters available? */
535 if (uid_eq(sbi->s_resuid, current_fsuid()) ||
536 (!gid_eq(sbi->s_resgid, GLOBAL_ROOT_GID) && in_group_p(sbi->s_resgid)) ||
537 capable(CAP_SYS_RESOURCE) ||
538 (flags & EXT4_MB_USE_ROOT_BLOCKS)) {
539
540 if (free_clusters >= (nclusters + dirty_clusters +
541 resv_clusters))
542 return 1;
543 }
544 /* No free blocks. Let's see if we can dip into reserved pool */
545 if (flags & EXT4_MB_USE_RESERVED) {
546 if (free_clusters >= (nclusters + dirty_clusters))
547 return 1;
548 }
549
550 return 0;
551}
552
553int ext4_claim_free_clusters(struct ext4_sb_info *sbi,
554 s64 nclusters, unsigned int flags)
555{
556 if (ext4_has_free_clusters(sbi, nclusters, flags)) {
557 percpu_counter_add(&sbi->s_dirtyclusters_counter, nclusters);
558 return 0;
559 } else
560 return -ENOSPC;
561}
562
563/**
564 * ext4_should_retry_alloc()
565 * @sb: super block
566 * @retries number of attemps has been made
567 *
568 * ext4_should_retry_alloc() is called when ENOSPC is returned, and if
569 * it is profitable to retry the operation, this function will wait
570 * for the current or committing transaction to complete, and then
571 * return TRUE.
572 *
573 * if the total number of retries exceed three times, return FALSE.
574 */
575int ext4_should_retry_alloc(struct super_block *sb, int *retries)
576{
577 if (!ext4_has_free_clusters(EXT4_SB(sb), 1, 0) ||
578 (*retries)++ > 3 ||
579 !EXT4_SB(sb)->s_journal)
580 return 0;
581
582 jbd_debug(1, "%s: retrying operation after ENOSPC\n", sb->s_id);
583
584 return jbd2_journal_force_commit_nested(EXT4_SB(sb)->s_journal);
585}
586
587/*
588 * ext4_new_meta_blocks() -- allocate block for meta data (indexing) blocks
589 *
590 * @handle: handle to this transaction
591 * @inode: file inode
592 * @goal: given target block(filesystem wide)
593 * @count: pointer to total number of clusters needed
594 * @errp: error code
595 *
596 * Return 1st allocated block number on success, *count stores total account
597 * error stores in errp pointer
598 */
599ext4_fsblk_t ext4_new_meta_blocks(handle_t *handle, struct inode *inode,
600 ext4_fsblk_t goal, unsigned int flags,
601 unsigned long *count, int *errp)
602{
603 struct ext4_allocation_request ar;
604 ext4_fsblk_t ret;
605
606 memset(&ar, 0, sizeof(ar));
607 /* Fill with neighbour allocated blocks */
608 ar.inode = inode;
609 ar.goal = goal;
610 ar.len = count ? *count : 1;
611 ar.flags = flags;
612
613 ret = ext4_mb_new_blocks(handle, &ar, errp);
614 if (count)
615 *count = ar.len;
616 /*
617 * Account for the allocated meta blocks. We will never
618 * fail EDQUOT for metdata, but we do account for it.
619 */
620 if (!(*errp) &&
621 ext4_test_inode_state(inode, EXT4_STATE_DELALLOC_RESERVED)) {
622 spin_lock(&EXT4_I(inode)->i_block_reservation_lock);
623 EXT4_I(inode)->i_allocated_meta_blocks += ar.len;
624 spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
625 dquot_alloc_block_nofail(inode,
626 EXT4_C2B(EXT4_SB(inode->i_sb), ar.len));
627 }
628 return ret;
629}
630
631/**
632 * ext4_count_free_clusters() -- count filesystem free clusters
633 * @sb: superblock
634 *
635 * Adds up the number of free clusters from each block group.
636 */
637ext4_fsblk_t ext4_count_free_clusters(struct super_block *sb)
638{
639 ext4_fsblk_t desc_count;
640 struct ext4_group_desc *gdp;
641 ext4_group_t i;
642 ext4_group_t ngroups = ext4_get_groups_count(sb);
643 struct ext4_group_info *grp;
644#ifdef EXT4FS_DEBUG
645 struct ext4_super_block *es;
646 ext4_fsblk_t bitmap_count;
647 unsigned int x;
648 struct buffer_head *bitmap_bh = NULL;
649
650 es = EXT4_SB(sb)->s_es;
651 desc_count = 0;
652 bitmap_count = 0;
653 gdp = NULL;
654
655 for (i = 0; i < ngroups; i++) {
656 gdp = ext4_get_group_desc(sb, i, NULL);
657 if (!gdp)
658 continue;
659 grp = NULL;
660 if (EXT4_SB(sb)->s_group_info)
661 grp = ext4_get_group_info(sb, i);
662 if (!grp || !EXT4_MB_GRP_BBITMAP_CORRUPT(grp))
663 desc_count += ext4_free_group_clusters(sb, gdp);
664 brelse(bitmap_bh);
665 bitmap_bh = ext4_read_block_bitmap(sb, i);
666 if (bitmap_bh == NULL)
667 continue;
668
669 x = ext4_count_free(bitmap_bh->b_data,
670 EXT4_CLUSTERS_PER_GROUP(sb) / 8);
671 printk(KERN_DEBUG "group %u: stored = %d, counted = %u\n",
672 i, ext4_free_group_clusters(sb, gdp), x);
673 bitmap_count += x;
674 }
675 brelse(bitmap_bh);
676 printk(KERN_DEBUG "ext4_count_free_clusters: stored = %llu"
677 ", computed = %llu, %llu\n",
678 EXT4_NUM_B2C(EXT4_SB(sb), ext4_free_blocks_count(es)),
679 desc_count, bitmap_count);
680 return bitmap_count;
681#else
682 desc_count = 0;
683 for (i = 0; i < ngroups; i++) {
684 gdp = ext4_get_group_desc(sb, i, NULL);
685 if (!gdp)
686 continue;
687 grp = NULL;
688 if (EXT4_SB(sb)->s_group_info)
689 grp = ext4_get_group_info(sb, i);
690 if (!grp || !EXT4_MB_GRP_BBITMAP_CORRUPT(grp))
691 desc_count += ext4_free_group_clusters(sb, gdp);
692 }
693
694 return desc_count;
695#endif
696}
697
698static inline int test_root(ext4_group_t a, int b)
699{
700 while (1) {
701 if (a < b)
702 return 0;
703 if (a == b)
704 return 1;
705 if ((a % b) != 0)
706 return 0;
707 a = a / b;
708 }
709}
710
711static int ext4_group_sparse(ext4_group_t group)
712{
713 if (group <= 1)
714 return 1;
715 if (!(group & 1))
716 return 0;
717 return (test_root(group, 7) || test_root(group, 5) ||
718 test_root(group, 3));
719}
720
721/**
722 * ext4_bg_has_super - number of blocks used by the superblock in group
723 * @sb: superblock for filesystem
724 * @group: group number to check
725 *
726 * Return the number of blocks used by the superblock (primary or backup)
727 * in this group. Currently this will be only 0 or 1.
728 */
729int ext4_bg_has_super(struct super_block *sb, ext4_group_t group)
730{
731 if (EXT4_HAS_RO_COMPAT_FEATURE(sb,
732 EXT4_FEATURE_RO_COMPAT_SPARSE_SUPER) &&
733 !ext4_group_sparse(group))
734 return 0;
735 return 1;
736}
737
738static unsigned long ext4_bg_num_gdb_meta(struct super_block *sb,
739 ext4_group_t group)
740{
741 unsigned long metagroup = group / EXT4_DESC_PER_BLOCK(sb);
742 ext4_group_t first = metagroup * EXT4_DESC_PER_BLOCK(sb);
743 ext4_group_t last = first + EXT4_DESC_PER_BLOCK(sb) - 1;
744
745 if (group == first || group == first + 1 || group == last)
746 return 1;
747 return 0;
748}
749
750static unsigned long ext4_bg_num_gdb_nometa(struct super_block *sb,
751 ext4_group_t group)
752{
753 if (!ext4_bg_has_super(sb, group))
754 return 0;
755
756 if (EXT4_HAS_INCOMPAT_FEATURE(sb,EXT4_FEATURE_INCOMPAT_META_BG))
757 return le32_to_cpu(EXT4_SB(sb)->s_es->s_first_meta_bg);
758 else
759 return EXT4_SB(sb)->s_gdb_count;
760}
761
762/**
763 * ext4_bg_num_gdb - number of blocks used by the group table in group
764 * @sb: superblock for filesystem
765 * @group: group number to check
766 *
767 * Return the number of blocks used by the group descriptor table
768 * (primary or backup) in this group. In the future there may be a
769 * different number of descriptor blocks in each group.
770 */
771unsigned long ext4_bg_num_gdb(struct super_block *sb, ext4_group_t group)
772{
773 unsigned long first_meta_bg =
774 le32_to_cpu(EXT4_SB(sb)->s_es->s_first_meta_bg);
775 unsigned long metagroup = group / EXT4_DESC_PER_BLOCK(sb);
776
777 if (!EXT4_HAS_INCOMPAT_FEATURE(sb,EXT4_FEATURE_INCOMPAT_META_BG) ||
778 metagroup < first_meta_bg)
779 return ext4_bg_num_gdb_nometa(sb, group);
780
781 return ext4_bg_num_gdb_meta(sb,group);
782
783}
784
785/*
786 * This function returns the number of file system metadata clusters at
787 * the beginning of a block group, including the reserved gdt blocks.
788 */
789static unsigned ext4_num_base_meta_clusters(struct super_block *sb,
790 ext4_group_t block_group)
791{
792 struct ext4_sb_info *sbi = EXT4_SB(sb);
793 unsigned num;
794
795 /* Check for superblock and gdt backups in this group */
796 num = ext4_bg_has_super(sb, block_group);
797
798 if (!EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_META_BG) ||
799 block_group < le32_to_cpu(sbi->s_es->s_first_meta_bg) *
800 sbi->s_desc_per_block) {
801 if (num) {
802 num += ext4_bg_num_gdb(sb, block_group);
803 num += le16_to_cpu(sbi->s_es->s_reserved_gdt_blocks);
804 }
805 } else { /* For META_BG_BLOCK_GROUPS */
806 num += ext4_bg_num_gdb(sb, block_group);
807 }
808 return EXT4_NUM_B2C(sbi, num);
809}
810/**
811 * ext4_inode_to_goal_block - return a hint for block allocation
812 * @inode: inode for block allocation
813 *
814 * Return the ideal location to start allocating blocks for a
815 * newly created inode.
816 */
817ext4_fsblk_t ext4_inode_to_goal_block(struct inode *inode)
818{
819 struct ext4_inode_info *ei = EXT4_I(inode);
820 ext4_group_t block_group;
821 ext4_grpblk_t colour;
822 int flex_size = ext4_flex_bg_size(EXT4_SB(inode->i_sb));
823 ext4_fsblk_t bg_start;
824 ext4_fsblk_t last_block;
825
826 block_group = ei->i_block_group;
827 if (flex_size >= EXT4_FLEX_SIZE_DIR_ALLOC_SCHEME) {
828 /*
829 * If there are at least EXT4_FLEX_SIZE_DIR_ALLOC_SCHEME
830 * block groups per flexgroup, reserve the first block
831 * group for directories and special files. Regular
832 * files will start at the second block group. This
833 * tends to speed up directory access and improves
834 * fsck times.
835 */
836 block_group &= ~(flex_size-1);
837 if (S_ISREG(inode->i_mode))
838 block_group++;
839 }
840 bg_start = ext4_group_first_block_no(inode->i_sb, block_group);
841 last_block = ext4_blocks_count(EXT4_SB(inode->i_sb)->s_es) - 1;
842
843 /*
844 * If we are doing delayed allocation, we don't need take
845 * colour into account.
846 */
847 if (test_opt(inode->i_sb, DELALLOC))
848 return bg_start;
849
850 if (bg_start + EXT4_BLOCKS_PER_GROUP(inode->i_sb) <= last_block)
851 colour = (current->pid % 16) *
852 (EXT4_BLOCKS_PER_GROUP(inode->i_sb) / 16);
853 else
854 colour = (current->pid % 16) * ((last_block - bg_start) / 16);
855 return bg_start + colour;
856}
857
1/*
2 * linux/fs/ext4/balloc.c
3 *
4 * Copyright (C) 1992, 1993, 1994, 1995
5 * Remy Card (card@masi.ibp.fr)
6 * Laboratoire MASI - Institut Blaise Pascal
7 * Universite Pierre et Marie Curie (Paris VI)
8 *
9 * Enhanced block allocation by Stephen Tweedie (sct@redhat.com), 1993
10 * Big-endian to little-endian byte-swapping/bitmaps by
11 * David S. Miller (davem@caip.rutgers.edu), 1995
12 */
13
14#include <linux/time.h>
15#include <linux/capability.h>
16#include <linux/fs.h>
17#include <linux/jbd2.h>
18#include <linux/quotaops.h>
19#include <linux/buffer_head.h>
20#include "ext4.h"
21#include "ext4_jbd2.h"
22#include "mballoc.h"
23
24#include <trace/events/ext4.h>
25
26/*
27 * balloc.c contains the blocks allocation and deallocation routines
28 */
29
30/*
31 * Calculate the block group number and offset, given a block number
32 */
33void ext4_get_group_no_and_offset(struct super_block *sb, ext4_fsblk_t blocknr,
34 ext4_group_t *blockgrpp, ext4_grpblk_t *offsetp)
35{
36 struct ext4_super_block *es = EXT4_SB(sb)->s_es;
37 ext4_grpblk_t offset;
38
39 blocknr = blocknr - le32_to_cpu(es->s_first_data_block);
40 offset = do_div(blocknr, EXT4_BLOCKS_PER_GROUP(sb));
41 if (offsetp)
42 *offsetp = offset;
43 if (blockgrpp)
44 *blockgrpp = blocknr;
45
46}
47
48static int ext4_block_in_group(struct super_block *sb, ext4_fsblk_t block,
49 ext4_group_t block_group)
50{
51 ext4_group_t actual_group;
52 ext4_get_group_no_and_offset(sb, block, &actual_group, NULL);
53 if (actual_group == block_group)
54 return 1;
55 return 0;
56}
57
58static int ext4_group_used_meta_blocks(struct super_block *sb,
59 ext4_group_t block_group,
60 struct ext4_group_desc *gdp)
61{
62 ext4_fsblk_t tmp;
63 struct ext4_sb_info *sbi = EXT4_SB(sb);
64 /* block bitmap, inode bitmap, and inode table blocks */
65 int used_blocks = sbi->s_itb_per_group + 2;
66
67 if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_FLEX_BG)) {
68 if (!ext4_block_in_group(sb, ext4_block_bitmap(sb, gdp),
69 block_group))
70 used_blocks--;
71
72 if (!ext4_block_in_group(sb, ext4_inode_bitmap(sb, gdp),
73 block_group))
74 used_blocks--;
75
76 tmp = ext4_inode_table(sb, gdp);
77 for (; tmp < ext4_inode_table(sb, gdp) +
78 sbi->s_itb_per_group; tmp++) {
79 if (!ext4_block_in_group(sb, tmp, block_group))
80 used_blocks -= 1;
81 }
82 }
83 return used_blocks;
84}
85
86/* Initializes an uninitialized block bitmap if given, and returns the
87 * number of blocks free in the group. */
88unsigned ext4_init_block_bitmap(struct super_block *sb, struct buffer_head *bh,
89 ext4_group_t block_group, struct ext4_group_desc *gdp)
90{
91 int bit, bit_max;
92 ext4_group_t ngroups = ext4_get_groups_count(sb);
93 unsigned free_blocks, group_blocks;
94 struct ext4_sb_info *sbi = EXT4_SB(sb);
95
96 if (bh) {
97 J_ASSERT_BH(bh, buffer_locked(bh));
98
99 /* If checksum is bad mark all blocks used to prevent allocation
100 * essentially implementing a per-group read-only flag. */
101 if (!ext4_group_desc_csum_verify(sbi, block_group, gdp)) {
102 ext4_error(sb, "Checksum bad for group %u",
103 block_group);
104 ext4_free_blks_set(sb, gdp, 0);
105 ext4_free_inodes_set(sb, gdp, 0);
106 ext4_itable_unused_set(sb, gdp, 0);
107 memset(bh->b_data, 0xff, sb->s_blocksize);
108 return 0;
109 }
110 memset(bh->b_data, 0, sb->s_blocksize);
111 }
112
113 /* Check for superblock and gdt backups in this group */
114 bit_max = ext4_bg_has_super(sb, block_group);
115
116 if (!EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_META_BG) ||
117 block_group < le32_to_cpu(sbi->s_es->s_first_meta_bg) *
118 sbi->s_desc_per_block) {
119 if (bit_max) {
120 bit_max += ext4_bg_num_gdb(sb, block_group);
121 bit_max +=
122 le16_to_cpu(sbi->s_es->s_reserved_gdt_blocks);
123 }
124 } else { /* For META_BG_BLOCK_GROUPS */
125 bit_max += ext4_bg_num_gdb(sb, block_group);
126 }
127
128 if (block_group == ngroups - 1) {
129 /*
130 * Even though mke2fs always initialize first and last group
131 * if some other tool enabled the EXT4_BG_BLOCK_UNINIT we need
132 * to make sure we calculate the right free blocks
133 */
134 group_blocks = ext4_blocks_count(sbi->s_es) -
135 ext4_group_first_block_no(sb, ngroups - 1);
136 } else {
137 group_blocks = EXT4_BLOCKS_PER_GROUP(sb);
138 }
139
140 free_blocks = group_blocks - bit_max;
141
142 if (bh) {
143 ext4_fsblk_t start, tmp;
144 int flex_bg = 0;
145
146 for (bit = 0; bit < bit_max; bit++)
147 ext4_set_bit(bit, bh->b_data);
148
149 start = ext4_group_first_block_no(sb, block_group);
150
151 if (EXT4_HAS_INCOMPAT_FEATURE(sb,
152 EXT4_FEATURE_INCOMPAT_FLEX_BG))
153 flex_bg = 1;
154
155 /* Set bits for block and inode bitmaps, and inode table */
156 tmp = ext4_block_bitmap(sb, gdp);
157 if (!flex_bg || ext4_block_in_group(sb, tmp, block_group))
158 ext4_set_bit(tmp - start, bh->b_data);
159
160 tmp = ext4_inode_bitmap(sb, gdp);
161 if (!flex_bg || ext4_block_in_group(sb, tmp, block_group))
162 ext4_set_bit(tmp - start, bh->b_data);
163
164 tmp = ext4_inode_table(sb, gdp);
165 for (; tmp < ext4_inode_table(sb, gdp) +
166 sbi->s_itb_per_group; tmp++) {
167 if (!flex_bg ||
168 ext4_block_in_group(sb, tmp, block_group))
169 ext4_set_bit(tmp - start, bh->b_data);
170 }
171 /*
172 * Also if the number of blocks within the group is
173 * less than the blocksize * 8 ( which is the size
174 * of bitmap ), set rest of the block bitmap to 1
175 */
176 ext4_mark_bitmap_end(group_blocks, sb->s_blocksize * 8,
177 bh->b_data);
178 }
179 return free_blocks - ext4_group_used_meta_blocks(sb, block_group, gdp);
180}
181
182
183/*
184 * The free blocks are managed by bitmaps. A file system contains several
185 * blocks groups. Each group contains 1 bitmap block for blocks, 1 bitmap
186 * block for inodes, N blocks for the inode table and data blocks.
187 *
188 * The file system contains group descriptors which are located after the
189 * super block. Each descriptor contains the number of the bitmap block and
190 * the free blocks count in the block. The descriptors are loaded in memory
191 * when a file system is mounted (see ext4_fill_super).
192 */
193
194/**
195 * ext4_get_group_desc() -- load group descriptor from disk
196 * @sb: super block
197 * @block_group: given block group
198 * @bh: pointer to the buffer head to store the block
199 * group descriptor
200 */
201struct ext4_group_desc * ext4_get_group_desc(struct super_block *sb,
202 ext4_group_t block_group,
203 struct buffer_head **bh)
204{
205 unsigned int group_desc;
206 unsigned int offset;
207 ext4_group_t ngroups = ext4_get_groups_count(sb);
208 struct ext4_group_desc *desc;
209 struct ext4_sb_info *sbi = EXT4_SB(sb);
210
211 if (block_group >= ngroups) {
212 ext4_error(sb, "block_group >= groups_count - block_group = %u,"
213 " groups_count = %u", block_group, ngroups);
214
215 return NULL;
216 }
217
218 group_desc = block_group >> EXT4_DESC_PER_BLOCK_BITS(sb);
219 offset = block_group & (EXT4_DESC_PER_BLOCK(sb) - 1);
220 if (!sbi->s_group_desc[group_desc]) {
221 ext4_error(sb, "Group descriptor not loaded - "
222 "block_group = %u, group_desc = %u, desc = %u",
223 block_group, group_desc, offset);
224 return NULL;
225 }
226
227 desc = (struct ext4_group_desc *)(
228 (__u8 *)sbi->s_group_desc[group_desc]->b_data +
229 offset * EXT4_DESC_SIZE(sb));
230 if (bh)
231 *bh = sbi->s_group_desc[group_desc];
232 return desc;
233}
234
235static int ext4_valid_block_bitmap(struct super_block *sb,
236 struct ext4_group_desc *desc,
237 unsigned int block_group,
238 struct buffer_head *bh)
239{
240 ext4_grpblk_t offset;
241 ext4_grpblk_t next_zero_bit;
242 ext4_fsblk_t bitmap_blk;
243 ext4_fsblk_t group_first_block;
244
245 if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_FLEX_BG)) {
246 /* with FLEX_BG, the inode/block bitmaps and itable
247 * blocks may not be in the group at all
248 * so the bitmap validation will be skipped for those groups
249 * or it has to also read the block group where the bitmaps
250 * are located to verify they are set.
251 */
252 return 1;
253 }
254 group_first_block = ext4_group_first_block_no(sb, block_group);
255
256 /* check whether block bitmap block number is set */
257 bitmap_blk = ext4_block_bitmap(sb, desc);
258 offset = bitmap_blk - group_first_block;
259 if (!ext4_test_bit(offset, bh->b_data))
260 /* bad block bitmap */
261 goto err_out;
262
263 /* check whether the inode bitmap block number is set */
264 bitmap_blk = ext4_inode_bitmap(sb, desc);
265 offset = bitmap_blk - group_first_block;
266 if (!ext4_test_bit(offset, bh->b_data))
267 /* bad block bitmap */
268 goto err_out;
269
270 /* check whether the inode table block number is set */
271 bitmap_blk = ext4_inode_table(sb, desc);
272 offset = bitmap_blk - group_first_block;
273 next_zero_bit = ext4_find_next_zero_bit(bh->b_data,
274 offset + EXT4_SB(sb)->s_itb_per_group,
275 offset);
276 if (next_zero_bit >= offset + EXT4_SB(sb)->s_itb_per_group)
277 /* good bitmap for inode tables */
278 return 1;
279
280err_out:
281 ext4_error(sb, "Invalid block bitmap - block_group = %d, block = %llu",
282 block_group, bitmap_blk);
283 return 0;
284}
285/**
286 * ext4_read_block_bitmap()
287 * @sb: super block
288 * @block_group: given block group
289 *
290 * Read the bitmap for a given block_group,and validate the
291 * bits for block/inode/inode tables are set in the bitmaps
292 *
293 * Return buffer_head on success or NULL in case of failure.
294 */
295struct buffer_head *
296ext4_read_block_bitmap(struct super_block *sb, ext4_group_t block_group)
297{
298 struct ext4_group_desc *desc;
299 struct buffer_head *bh = NULL;
300 ext4_fsblk_t bitmap_blk;
301
302 desc = ext4_get_group_desc(sb, block_group, NULL);
303 if (!desc)
304 return NULL;
305 bitmap_blk = ext4_block_bitmap(sb, desc);
306 bh = sb_getblk(sb, bitmap_blk);
307 if (unlikely(!bh)) {
308 ext4_error(sb, "Cannot read block bitmap - "
309 "block_group = %u, block_bitmap = %llu",
310 block_group, bitmap_blk);
311 return NULL;
312 }
313
314 if (bitmap_uptodate(bh))
315 return bh;
316
317 lock_buffer(bh);
318 if (bitmap_uptodate(bh)) {
319 unlock_buffer(bh);
320 return bh;
321 }
322 ext4_lock_group(sb, block_group);
323 if (desc->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) {
324 ext4_init_block_bitmap(sb, bh, block_group, desc);
325 set_bitmap_uptodate(bh);
326 set_buffer_uptodate(bh);
327 ext4_unlock_group(sb, block_group);
328 unlock_buffer(bh);
329 return bh;
330 }
331 ext4_unlock_group(sb, block_group);
332 if (buffer_uptodate(bh)) {
333 /*
334 * if not uninit if bh is uptodate,
335 * bitmap is also uptodate
336 */
337 set_bitmap_uptodate(bh);
338 unlock_buffer(bh);
339 return bh;
340 }
341 /*
342 * submit the buffer_head for read. We can
343 * safely mark the bitmap as uptodate now.
344 * We do it here so the bitmap uptodate bit
345 * get set with buffer lock held.
346 */
347 trace_ext4_read_block_bitmap_load(sb, block_group);
348 set_bitmap_uptodate(bh);
349 if (bh_submit_read(bh) < 0) {
350 put_bh(bh);
351 ext4_error(sb, "Cannot read block bitmap - "
352 "block_group = %u, block_bitmap = %llu",
353 block_group, bitmap_blk);
354 return NULL;
355 }
356 ext4_valid_block_bitmap(sb, desc, block_group, bh);
357 /*
358 * file system mounted not to panic on error,
359 * continue with corrupt bitmap
360 */
361 return bh;
362}
363
364/**
365 * ext4_has_free_blocks()
366 * @sbi: in-core super block structure.
367 * @nblocks: number of needed blocks
368 *
369 * Check if filesystem has nblocks free & available for allocation.
370 * On success return 1, return 0 on failure.
371 */
372static int ext4_has_free_blocks(struct ext4_sb_info *sbi,
373 s64 nblocks, unsigned int flags)
374{
375 s64 free_blocks, dirty_blocks, root_blocks;
376 struct percpu_counter *fbc = &sbi->s_freeblocks_counter;
377 struct percpu_counter *dbc = &sbi->s_dirtyblocks_counter;
378
379 free_blocks = percpu_counter_read_positive(fbc);
380 dirty_blocks = percpu_counter_read_positive(dbc);
381 root_blocks = ext4_r_blocks_count(sbi->s_es);
382
383 if (free_blocks - (nblocks + root_blocks + dirty_blocks) <
384 EXT4_FREEBLOCKS_WATERMARK) {
385 free_blocks = percpu_counter_sum_positive(fbc);
386 dirty_blocks = percpu_counter_sum_positive(dbc);
387 }
388 /* Check whether we have space after
389 * accounting for current dirty blocks & root reserved blocks.
390 */
391 if (free_blocks >= ((root_blocks + nblocks) + dirty_blocks))
392 return 1;
393
394 /* Hm, nope. Are (enough) root reserved blocks available? */
395 if (sbi->s_resuid == current_fsuid() ||
396 ((sbi->s_resgid != 0) && in_group_p(sbi->s_resgid)) ||
397 capable(CAP_SYS_RESOURCE) ||
398 (flags & EXT4_MB_USE_ROOT_BLOCKS)) {
399
400 if (free_blocks >= (nblocks + dirty_blocks))
401 return 1;
402 }
403
404 return 0;
405}
406
407int ext4_claim_free_blocks(struct ext4_sb_info *sbi,
408 s64 nblocks, unsigned int flags)
409{
410 if (ext4_has_free_blocks(sbi, nblocks, flags)) {
411 percpu_counter_add(&sbi->s_dirtyblocks_counter, nblocks);
412 return 0;
413 } else
414 return -ENOSPC;
415}
416
417/**
418 * ext4_should_retry_alloc()
419 * @sb: super block
420 * @retries number of attemps has been made
421 *
422 * ext4_should_retry_alloc() is called when ENOSPC is returned, and if
423 * it is profitable to retry the operation, this function will wait
424 * for the current or committing transaction to complete, and then
425 * return TRUE.
426 *
427 * if the total number of retries exceed three times, return FALSE.
428 */
429int ext4_should_retry_alloc(struct super_block *sb, int *retries)
430{
431 if (!ext4_has_free_blocks(EXT4_SB(sb), 1, 0) ||
432 (*retries)++ > 3 ||
433 !EXT4_SB(sb)->s_journal)
434 return 0;
435
436 jbd_debug(1, "%s: retrying operation after ENOSPC\n", sb->s_id);
437
438 return jbd2_journal_force_commit_nested(EXT4_SB(sb)->s_journal);
439}
440
441/*
442 * ext4_new_meta_blocks() -- allocate block for meta data (indexing) blocks
443 *
444 * @handle: handle to this transaction
445 * @inode: file inode
446 * @goal: given target block(filesystem wide)
447 * @count: pointer to total number of blocks needed
448 * @errp: error code
449 *
450 * Return 1st allocated block number on success, *count stores total account
451 * error stores in errp pointer
452 */
453ext4_fsblk_t ext4_new_meta_blocks(handle_t *handle, struct inode *inode,
454 ext4_fsblk_t goal, unsigned int flags,
455 unsigned long *count, int *errp)
456{
457 struct ext4_allocation_request ar;
458 ext4_fsblk_t ret;
459
460 memset(&ar, 0, sizeof(ar));
461 /* Fill with neighbour allocated blocks */
462 ar.inode = inode;
463 ar.goal = goal;
464 ar.len = count ? *count : 1;
465 ar.flags = flags;
466
467 ret = ext4_mb_new_blocks(handle, &ar, errp);
468 if (count)
469 *count = ar.len;
470 /*
471 * Account for the allocated meta blocks. We will never
472 * fail EDQUOT for metdata, but we do account for it.
473 */
474 if (!(*errp) &&
475 ext4_test_inode_state(inode, EXT4_STATE_DELALLOC_RESERVED)) {
476 spin_lock(&EXT4_I(inode)->i_block_reservation_lock);
477 EXT4_I(inode)->i_allocated_meta_blocks += ar.len;
478 spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
479 dquot_alloc_block_nofail(inode, ar.len);
480 }
481 return ret;
482}
483
484/**
485 * ext4_count_free_blocks() -- count filesystem free blocks
486 * @sb: superblock
487 *
488 * Adds up the number of free blocks from each block group.
489 */
490ext4_fsblk_t ext4_count_free_blocks(struct super_block *sb)
491{
492 ext4_fsblk_t desc_count;
493 struct ext4_group_desc *gdp;
494 ext4_group_t i;
495 ext4_group_t ngroups = ext4_get_groups_count(sb);
496#ifdef EXT4FS_DEBUG
497 struct ext4_super_block *es;
498 ext4_fsblk_t bitmap_count;
499 unsigned int x;
500 struct buffer_head *bitmap_bh = NULL;
501
502 es = EXT4_SB(sb)->s_es;
503 desc_count = 0;
504 bitmap_count = 0;
505 gdp = NULL;
506
507 for (i = 0; i < ngroups; i++) {
508 gdp = ext4_get_group_desc(sb, i, NULL);
509 if (!gdp)
510 continue;
511 desc_count += ext4_free_blks_count(sb, gdp);
512 brelse(bitmap_bh);
513 bitmap_bh = ext4_read_block_bitmap(sb, i);
514 if (bitmap_bh == NULL)
515 continue;
516
517 x = ext4_count_free(bitmap_bh, sb->s_blocksize);
518 printk(KERN_DEBUG "group %u: stored = %d, counted = %u\n",
519 i, ext4_free_blks_count(sb, gdp), x);
520 bitmap_count += x;
521 }
522 brelse(bitmap_bh);
523 printk(KERN_DEBUG "ext4_count_free_blocks: stored = %llu"
524 ", computed = %llu, %llu\n", ext4_free_blocks_count(es),
525 desc_count, bitmap_count);
526 return bitmap_count;
527#else
528 desc_count = 0;
529 for (i = 0; i < ngroups; i++) {
530 gdp = ext4_get_group_desc(sb, i, NULL);
531 if (!gdp)
532 continue;
533 desc_count += ext4_free_blks_count(sb, gdp);
534 }
535
536 return desc_count;
537#endif
538}
539
540static inline int test_root(ext4_group_t a, int b)
541{
542 int num = b;
543
544 while (a > num)
545 num *= b;
546 return num == a;
547}
548
549static int ext4_group_sparse(ext4_group_t group)
550{
551 if (group <= 1)
552 return 1;
553 if (!(group & 1))
554 return 0;
555 return (test_root(group, 7) || test_root(group, 5) ||
556 test_root(group, 3));
557}
558
559/**
560 * ext4_bg_has_super - number of blocks used by the superblock in group
561 * @sb: superblock for filesystem
562 * @group: group number to check
563 *
564 * Return the number of blocks used by the superblock (primary or backup)
565 * in this group. Currently this will be only 0 or 1.
566 */
567int ext4_bg_has_super(struct super_block *sb, ext4_group_t group)
568{
569 if (EXT4_HAS_RO_COMPAT_FEATURE(sb,
570 EXT4_FEATURE_RO_COMPAT_SPARSE_SUPER) &&
571 !ext4_group_sparse(group))
572 return 0;
573 return 1;
574}
575
576static unsigned long ext4_bg_num_gdb_meta(struct super_block *sb,
577 ext4_group_t group)
578{
579 unsigned long metagroup = group / EXT4_DESC_PER_BLOCK(sb);
580 ext4_group_t first = metagroup * EXT4_DESC_PER_BLOCK(sb);
581 ext4_group_t last = first + EXT4_DESC_PER_BLOCK(sb) - 1;
582
583 if (group == first || group == first + 1 || group == last)
584 return 1;
585 return 0;
586}
587
588static unsigned long ext4_bg_num_gdb_nometa(struct super_block *sb,
589 ext4_group_t group)
590{
591 if (!ext4_bg_has_super(sb, group))
592 return 0;
593
594 if (EXT4_HAS_INCOMPAT_FEATURE(sb,EXT4_FEATURE_INCOMPAT_META_BG))
595 return le32_to_cpu(EXT4_SB(sb)->s_es->s_first_meta_bg);
596 else
597 return EXT4_SB(sb)->s_gdb_count;
598}
599
600/**
601 * ext4_bg_num_gdb - number of blocks used by the group table in group
602 * @sb: superblock for filesystem
603 * @group: group number to check
604 *
605 * Return the number of blocks used by the group descriptor table
606 * (primary or backup) in this group. In the future there may be a
607 * different number of descriptor blocks in each group.
608 */
609unsigned long ext4_bg_num_gdb(struct super_block *sb, ext4_group_t group)
610{
611 unsigned long first_meta_bg =
612 le32_to_cpu(EXT4_SB(sb)->s_es->s_first_meta_bg);
613 unsigned long metagroup = group / EXT4_DESC_PER_BLOCK(sb);
614
615 if (!EXT4_HAS_INCOMPAT_FEATURE(sb,EXT4_FEATURE_INCOMPAT_META_BG) ||
616 metagroup < first_meta_bg)
617 return ext4_bg_num_gdb_nometa(sb, group);
618
619 return ext4_bg_num_gdb_meta(sb,group);
620
621}
622
623/**
624 * ext4_inode_to_goal_block - return a hint for block allocation
625 * @inode: inode for block allocation
626 *
627 * Return the ideal location to start allocating blocks for a
628 * newly created inode.
629 */
630ext4_fsblk_t ext4_inode_to_goal_block(struct inode *inode)
631{
632 struct ext4_inode_info *ei = EXT4_I(inode);
633 ext4_group_t block_group;
634 ext4_grpblk_t colour;
635 int flex_size = ext4_flex_bg_size(EXT4_SB(inode->i_sb));
636 ext4_fsblk_t bg_start;
637 ext4_fsblk_t last_block;
638
639 block_group = ei->i_block_group;
640 if (flex_size >= EXT4_FLEX_SIZE_DIR_ALLOC_SCHEME) {
641 /*
642 * If there are at least EXT4_FLEX_SIZE_DIR_ALLOC_SCHEME
643 * block groups per flexgroup, reserve the first block
644 * group for directories and special files. Regular
645 * files will start at the second block group. This
646 * tends to speed up directory access and improves
647 * fsck times.
648 */
649 block_group &= ~(flex_size-1);
650 if (S_ISREG(inode->i_mode))
651 block_group++;
652 }
653 bg_start = ext4_group_first_block_no(inode->i_sb, block_group);
654 last_block = ext4_blocks_count(EXT4_SB(inode->i_sb)->s_es) - 1;
655
656 /*
657 * If we are doing delayed allocation, we don't need take
658 * colour into account.
659 */
660 if (test_opt(inode->i_sb, DELALLOC))
661 return bg_start;
662
663 if (bg_start + EXT4_BLOCKS_PER_GROUP(inode->i_sb) <= last_block)
664 colour = (current->pid % 16) *
665 (EXT4_BLOCKS_PER_GROUP(inode->i_sb) / 16);
666 else
667 colour = (current->pid % 16) * ((last_block - bg_start) / 16);
668 return bg_start + colour;
669}
670