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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/quotaops.h>
18#include <linux/buffer_head.h>
19#include "ext4.h"
20#include "ext4_jbd2.h"
21#include "mballoc.h"
22
23#include <trace/events/ext4.h>
24
25static unsigned ext4_num_base_meta_clusters(struct super_block *sb,
26 ext4_group_t block_group);
27/*
28 * balloc.c contains the blocks allocation and deallocation routines
29 */
30
31/*
32 * Calculate block group number for a given block number
33 */
34ext4_group_t ext4_get_group_number(struct super_block *sb,
35 ext4_fsblk_t block)
36{
37 ext4_group_t group;
38
39 if (test_opt2(sb, STD_GROUP_SIZE))
40 group = (block -
41 le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block)) >>
42 (EXT4_BLOCK_SIZE_BITS(sb) + EXT4_CLUSTER_BITS(sb) + 3);
43 else
44 ext4_get_group_no_and_offset(sb, block, &group, NULL);
45 return group;
46}
47
48/*
49 * Calculate the block group number and offset into the block/cluster
50 * allocation bitmap, given a block number
51 */
52void ext4_get_group_no_and_offset(struct super_block *sb, ext4_fsblk_t blocknr,
53 ext4_group_t *blockgrpp, ext4_grpblk_t *offsetp)
54{
55 struct ext4_super_block *es = EXT4_SB(sb)->s_es;
56 ext4_grpblk_t offset;
57
58 blocknr = blocknr - le32_to_cpu(es->s_first_data_block);
59 offset = do_div(blocknr, EXT4_BLOCKS_PER_GROUP(sb)) >>
60 EXT4_SB(sb)->s_cluster_bits;
61 if (offsetp)
62 *offsetp = offset;
63 if (blockgrpp)
64 *blockgrpp = blocknr;
65
66}
67
68/*
69 * Check whether the 'block' lives within the 'block_group'. Returns 1 if so
70 * and 0 otherwise.
71 */
72static inline int ext4_block_in_group(struct super_block *sb,
73 ext4_fsblk_t block,
74 ext4_group_t block_group)
75{
76 ext4_group_t actual_group;
77
78 actual_group = ext4_get_group_number(sb, block);
79 return (actual_group == block_group) ? 1 : 0;
80}
81
82/* Return the number of clusters used for file system metadata; this
83 * represents the overhead needed by the file system.
84 */
85static unsigned ext4_num_overhead_clusters(struct super_block *sb,
86 ext4_group_t block_group,
87 struct ext4_group_desc *gdp)
88{
89 unsigned num_clusters;
90 int block_cluster = -1, inode_cluster = -1, itbl_cluster = -1, i, c;
91 ext4_fsblk_t start = ext4_group_first_block_no(sb, block_group);
92 ext4_fsblk_t itbl_blk;
93 struct ext4_sb_info *sbi = EXT4_SB(sb);
94
95 /* This is the number of clusters used by the superblock,
96 * block group descriptors, and reserved block group
97 * descriptor blocks */
98 num_clusters = ext4_num_base_meta_clusters(sb, block_group);
99
100 /*
101 * For the allocation bitmaps and inode table, we first need
102 * to check to see if the block is in the block group. If it
103 * is, then check to see if the cluster is already accounted
104 * for in the clusters used for the base metadata cluster, or
105 * if we can increment the base metadata cluster to include
106 * that block. Otherwise, we will have to track the cluster
107 * used for the allocation bitmap or inode table explicitly.
108 * Normally all of these blocks are contiguous, so the special
109 * case handling shouldn't be necessary except for *very*
110 * unusual file system layouts.
111 */
112 if (ext4_block_in_group(sb, ext4_block_bitmap(sb, gdp), block_group)) {
113 block_cluster = EXT4_B2C(sbi,
114 ext4_block_bitmap(sb, gdp) - start);
115 if (block_cluster < num_clusters)
116 block_cluster = -1;
117 else if (block_cluster == num_clusters) {
118 num_clusters++;
119 block_cluster = -1;
120 }
121 }
122
123 if (ext4_block_in_group(sb, ext4_inode_bitmap(sb, gdp), block_group)) {
124 inode_cluster = EXT4_B2C(sbi,
125 ext4_inode_bitmap(sb, gdp) - start);
126 if (inode_cluster < num_clusters)
127 inode_cluster = -1;
128 else if (inode_cluster == num_clusters) {
129 num_clusters++;
130 inode_cluster = -1;
131 }
132 }
133
134 itbl_blk = ext4_inode_table(sb, gdp);
135 for (i = 0; i < sbi->s_itb_per_group; i++) {
136 if (ext4_block_in_group(sb, itbl_blk + i, block_group)) {
137 c = EXT4_B2C(sbi, itbl_blk + i - start);
138 if ((c < num_clusters) || (c == inode_cluster) ||
139 (c == block_cluster) || (c == itbl_cluster))
140 continue;
141 if (c == num_clusters) {
142 num_clusters++;
143 continue;
144 }
145 num_clusters++;
146 itbl_cluster = c;
147 }
148 }
149
150 if (block_cluster != -1)
151 num_clusters++;
152 if (inode_cluster != -1)
153 num_clusters++;
154
155 return num_clusters;
156}
157
158static unsigned int num_clusters_in_group(struct super_block *sb,
159 ext4_group_t block_group)
160{
161 unsigned int blocks;
162
163 if (block_group == ext4_get_groups_count(sb) - 1) {
164 /*
165 * Even though mke2fs always initializes the first and
166 * last group, just in case some other tool was used,
167 * we need to make sure we calculate the right free
168 * blocks.
169 */
170 blocks = ext4_blocks_count(EXT4_SB(sb)->s_es) -
171 ext4_group_first_block_no(sb, block_group);
172 } else
173 blocks = EXT4_BLOCKS_PER_GROUP(sb);
174 return EXT4_NUM_B2C(EXT4_SB(sb), blocks);
175}
176
177/* Initializes an uninitialized block bitmap */
178static int ext4_init_block_bitmap(struct super_block *sb,
179 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 grp = ext4_get_group_info(sb, block_group);
195 if (!EXT4_MB_GRP_BBITMAP_CORRUPT(grp))
196 percpu_counter_sub(&sbi->s_freeclusters_counter,
197 grp->bb_free);
198 set_bit(EXT4_GROUP_INFO_BBITMAP_CORRUPT_BIT, &grp->bb_state);
199 if (!EXT4_MB_GRP_IBITMAP_CORRUPT(grp)) {
200 int count;
201 count = ext4_free_inodes_count(sb, gdp);
202 percpu_counter_sub(&sbi->s_freeinodes_counter,
203 count);
204 }
205 set_bit(EXT4_GROUP_INFO_IBITMAP_CORRUPT_BIT, &grp->bb_state);
206 return -EFSBADCRC;
207 }
208 memset(bh->b_data, 0, sb->s_blocksize);
209
210 bit_max = ext4_num_base_meta_clusters(sb, block_group);
211 if ((bit_max >> 3) >= bh->b_size)
212 return -EFSCORRUPTED;
213
214 for (bit = 0; bit < bit_max; bit++)
215 ext4_set_bit(bit, bh->b_data);
216
217 start = ext4_group_first_block_no(sb, block_group);
218
219 if (ext4_has_feature_flex_bg(sb))
220 flex_bg = 1;
221
222 /* Set bits for block and inode bitmaps, and inode table */
223 tmp = ext4_block_bitmap(sb, gdp);
224 if (!flex_bg || ext4_block_in_group(sb, tmp, block_group))
225 ext4_set_bit(EXT4_B2C(sbi, tmp - start), bh->b_data);
226
227 tmp = ext4_inode_bitmap(sb, gdp);
228 if (!flex_bg || ext4_block_in_group(sb, tmp, block_group))
229 ext4_set_bit(EXT4_B2C(sbi, tmp - start), bh->b_data);
230
231 tmp = ext4_inode_table(sb, gdp);
232 for (; tmp < ext4_inode_table(sb, gdp) +
233 sbi->s_itb_per_group; tmp++) {
234 if (!flex_bg || ext4_block_in_group(sb, tmp, block_group))
235 ext4_set_bit(EXT4_B2C(sbi, tmp - start), bh->b_data);
236 }
237
238 /*
239 * Also if the number of blocks within the group is less than
240 * the blocksize * 8 ( which is the size of bitmap ), set rest
241 * of the block bitmap to 1
242 */
243 ext4_mark_bitmap_end(num_clusters_in_group(sb, block_group),
244 sb->s_blocksize * 8, bh->b_data);
245 ext4_block_bitmap_csum_set(sb, block_group, gdp, bh);
246 ext4_group_desc_csum_set(sb, block_group, gdp);
247 return 0;
248}
249
250/* Return the number of free blocks in a block group. It is used when
251 * the block bitmap is uninitialized, so we can't just count the bits
252 * in the bitmap. */
253unsigned ext4_free_clusters_after_init(struct super_block *sb,
254 ext4_group_t block_group,
255 struct ext4_group_desc *gdp)
256{
257 return num_clusters_in_group(sb, block_group) -
258 ext4_num_overhead_clusters(sb, block_group, gdp);
259}
260
261/*
262 * The free blocks are managed by bitmaps. A file system contains several
263 * blocks groups. Each group contains 1 bitmap block for blocks, 1 bitmap
264 * block for inodes, N blocks for the inode table and data blocks.
265 *
266 * The file system contains group descriptors which are located after the
267 * super block. Each descriptor contains the number of the bitmap block and
268 * the free blocks count in the block. The descriptors are loaded in memory
269 * when a file system is mounted (see ext4_fill_super).
270 */
271
272/**
273 * ext4_get_group_desc() -- load group descriptor from disk
274 * @sb: super block
275 * @block_group: given block group
276 * @bh: pointer to the buffer head to store the block
277 * group descriptor
278 */
279struct ext4_group_desc * ext4_get_group_desc(struct super_block *sb,
280 ext4_group_t block_group,
281 struct buffer_head **bh)
282{
283 unsigned int group_desc;
284 unsigned int offset;
285 ext4_group_t ngroups = ext4_get_groups_count(sb);
286 struct ext4_group_desc *desc;
287 struct ext4_sb_info *sbi = EXT4_SB(sb);
288
289 if (block_group >= ngroups) {
290 ext4_error(sb, "block_group >= groups_count - block_group = %u,"
291 " groups_count = %u", block_group, ngroups);
292
293 return NULL;
294 }
295
296 group_desc = block_group >> EXT4_DESC_PER_BLOCK_BITS(sb);
297 offset = block_group & (EXT4_DESC_PER_BLOCK(sb) - 1);
298 if (!sbi->s_group_desc[group_desc]) {
299 ext4_error(sb, "Group descriptor not loaded - "
300 "block_group = %u, group_desc = %u, desc = %u",
301 block_group, group_desc, offset);
302 return NULL;
303 }
304
305 desc = (struct ext4_group_desc *)(
306 (__u8 *)sbi->s_group_desc[group_desc]->b_data +
307 offset * EXT4_DESC_SIZE(sb));
308 if (bh)
309 *bh = sbi->s_group_desc[group_desc];
310 return desc;
311}
312
313/*
314 * Return the block number which was discovered to be invalid, or 0 if
315 * the block bitmap is valid.
316 */
317static ext4_fsblk_t ext4_valid_block_bitmap(struct super_block *sb,
318 struct ext4_group_desc *desc,
319 ext4_group_t block_group,
320 struct buffer_head *bh)
321{
322 struct ext4_sb_info *sbi = EXT4_SB(sb);
323 ext4_grpblk_t offset;
324 ext4_grpblk_t next_zero_bit;
325 ext4_fsblk_t blk;
326 ext4_fsblk_t group_first_block;
327
328 if (ext4_has_feature_flex_bg(sb)) {
329 /* with FLEX_BG, the inode/block bitmaps and itable
330 * blocks may not be in the group at all
331 * so the bitmap validation will be skipped for those groups
332 * or it has to also read the block group where the bitmaps
333 * are located to verify they are set.
334 */
335 return 0;
336 }
337 group_first_block = ext4_group_first_block_no(sb, block_group);
338
339 /* check whether block bitmap block number is set */
340 blk = ext4_block_bitmap(sb, desc);
341 offset = blk - group_first_block;
342 if (!ext4_test_bit(EXT4_B2C(sbi, offset), bh->b_data))
343 /* bad block bitmap */
344 return blk;
345
346 /* check whether the inode bitmap block number is set */
347 blk = ext4_inode_bitmap(sb, desc);
348 offset = blk - group_first_block;
349 if (!ext4_test_bit(EXT4_B2C(sbi, offset), bh->b_data))
350 /* bad block bitmap */
351 return blk;
352
353 /* check whether the inode table block number is set */
354 blk = ext4_inode_table(sb, desc);
355 offset = blk - group_first_block;
356 next_zero_bit = ext4_find_next_zero_bit(bh->b_data,
357 EXT4_B2C(sbi, offset + EXT4_SB(sb)->s_itb_per_group),
358 EXT4_B2C(sbi, offset));
359 if (next_zero_bit <
360 EXT4_B2C(sbi, offset + EXT4_SB(sb)->s_itb_per_group))
361 /* bad bitmap for inode tables */
362 return blk;
363 return 0;
364}
365
366static int ext4_validate_block_bitmap(struct super_block *sb,
367 struct ext4_group_desc *desc,
368 ext4_group_t block_group,
369 struct buffer_head *bh)
370{
371 ext4_fsblk_t blk;
372 struct ext4_group_info *grp = ext4_get_group_info(sb, block_group);
373 struct ext4_sb_info *sbi = EXT4_SB(sb);
374
375 if (buffer_verified(bh))
376 return 0;
377 if (EXT4_MB_GRP_BBITMAP_CORRUPT(grp))
378 return -EFSCORRUPTED;
379
380 ext4_lock_group(sb, block_group);
381 if (unlikely(!ext4_block_bitmap_csum_verify(sb, block_group,
382 desc, bh))) {
383 ext4_unlock_group(sb, block_group);
384 ext4_error(sb, "bg %u: bad block bitmap checksum", block_group);
385 if (!EXT4_MB_GRP_BBITMAP_CORRUPT(grp))
386 percpu_counter_sub(&sbi->s_freeclusters_counter,
387 grp->bb_free);
388 set_bit(EXT4_GROUP_INFO_BBITMAP_CORRUPT_BIT, &grp->bb_state);
389 return -EFSBADCRC;
390 }
391 blk = ext4_valid_block_bitmap(sb, desc, block_group, bh);
392 if (unlikely(blk != 0)) {
393 ext4_unlock_group(sb, block_group);
394 ext4_error(sb, "bg %u: block %llu: invalid block bitmap",
395 block_group, blk);
396 if (!EXT4_MB_GRP_BBITMAP_CORRUPT(grp))
397 percpu_counter_sub(&sbi->s_freeclusters_counter,
398 grp->bb_free);
399 set_bit(EXT4_GROUP_INFO_BBITMAP_CORRUPT_BIT, &grp->bb_state);
400 return -EFSCORRUPTED;
401 }
402 set_buffer_verified(bh);
403 ext4_unlock_group(sb, block_group);
404 return 0;
405}
406
407/**
408 * ext4_read_block_bitmap_nowait()
409 * @sb: super block
410 * @block_group: given block group
411 *
412 * Read the bitmap for a given block_group,and validate the
413 * bits for block/inode/inode tables are set in the bitmaps
414 *
415 * Return buffer_head on success or NULL in case of failure.
416 */
417struct buffer_head *
418ext4_read_block_bitmap_nowait(struct super_block *sb, ext4_group_t block_group)
419{
420 struct ext4_group_desc *desc;
421 struct buffer_head *bh;
422 ext4_fsblk_t bitmap_blk;
423 int err;
424
425 desc = ext4_get_group_desc(sb, block_group, NULL);
426 if (!desc)
427 return ERR_PTR(-EFSCORRUPTED);
428 bitmap_blk = ext4_block_bitmap(sb, desc);
429 bh = sb_getblk(sb, bitmap_blk);
430 if (unlikely(!bh)) {
431 ext4_error(sb, "Cannot get buffer for block bitmap - "
432 "block_group = %u, block_bitmap = %llu",
433 block_group, bitmap_blk);
434 return ERR_PTR(-ENOMEM);
435 }
436
437 if (bitmap_uptodate(bh))
438 goto verify;
439
440 lock_buffer(bh);
441 if (bitmap_uptodate(bh)) {
442 unlock_buffer(bh);
443 goto verify;
444 }
445 ext4_lock_group(sb, block_group);
446 if (desc->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) {
447 err = ext4_init_block_bitmap(sb, bh, block_group, desc);
448 set_bitmap_uptodate(bh);
449 set_buffer_uptodate(bh);
450 ext4_unlock_group(sb, block_group);
451 unlock_buffer(bh);
452 if (err) {
453 ext4_error(sb, "Failed to init block bitmap for group "
454 "%u: %d", block_group, err);
455 goto out;
456 }
457 goto verify;
458 }
459 ext4_unlock_group(sb, block_group);
460 if (buffer_uptodate(bh)) {
461 /*
462 * if not uninit if bh is uptodate,
463 * bitmap is also uptodate
464 */
465 set_bitmap_uptodate(bh);
466 unlock_buffer(bh);
467 goto verify;
468 }
469 /*
470 * submit the buffer_head for reading
471 */
472 set_buffer_new(bh);
473 trace_ext4_read_block_bitmap_load(sb, block_group);
474 bh->b_end_io = ext4_end_bitmap_read;
475 get_bh(bh);
476 submit_bh(REQ_OP_READ, REQ_META | REQ_PRIO, bh);
477 return bh;
478verify:
479 err = ext4_validate_block_bitmap(sb, desc, block_group, bh);
480 if (err)
481 goto out;
482 return bh;
483out:
484 put_bh(bh);
485 return ERR_PTR(err);
486}
487
488/* Returns 0 on success, 1 on error */
489int ext4_wait_block_bitmap(struct super_block *sb, ext4_group_t block_group,
490 struct buffer_head *bh)
491{
492 struct ext4_group_desc *desc;
493
494 if (!buffer_new(bh))
495 return 0;
496 desc = ext4_get_group_desc(sb, block_group, NULL);
497 if (!desc)
498 return -EFSCORRUPTED;
499 wait_on_buffer(bh);
500 if (!buffer_uptodate(bh)) {
501 ext4_error(sb, "Cannot read block bitmap - "
502 "block_group = %u, block_bitmap = %llu",
503 block_group, (unsigned long long) bh->b_blocknr);
504 return -EIO;
505 }
506 clear_buffer_new(bh);
507 /* Panic or remount fs read-only if block bitmap is invalid */
508 return ext4_validate_block_bitmap(sb, desc, block_group, bh);
509}
510
511struct buffer_head *
512ext4_read_block_bitmap(struct super_block *sb, ext4_group_t block_group)
513{
514 struct buffer_head *bh;
515 int err;
516
517 bh = ext4_read_block_bitmap_nowait(sb, block_group);
518 if (IS_ERR(bh))
519 return bh;
520 err = ext4_wait_block_bitmap(sb, block_group, bh);
521 if (err) {
522 put_bh(bh);
523 return ERR_PTR(err);
524 }
525 return bh;
526}
527
528/**
529 * ext4_has_free_clusters()
530 * @sbi: in-core super block structure.
531 * @nclusters: number of needed blocks
532 * @flags: flags from ext4_mb_new_blocks()
533 *
534 * Check if filesystem has nclusters free & available for allocation.
535 * On success return 1, return 0 on failure.
536 */
537static int ext4_has_free_clusters(struct ext4_sb_info *sbi,
538 s64 nclusters, unsigned int flags)
539{
540 s64 free_clusters, dirty_clusters, rsv, resv_clusters;
541 struct percpu_counter *fcc = &sbi->s_freeclusters_counter;
542 struct percpu_counter *dcc = &sbi->s_dirtyclusters_counter;
543
544 free_clusters = percpu_counter_read_positive(fcc);
545 dirty_clusters = percpu_counter_read_positive(dcc);
546 resv_clusters = atomic64_read(&sbi->s_resv_clusters);
547
548 /*
549 * r_blocks_count should always be multiple of the cluster ratio so
550 * we are safe to do a plane bit shift only.
551 */
552 rsv = (ext4_r_blocks_count(sbi->s_es) >> sbi->s_cluster_bits) +
553 resv_clusters;
554
555 if (free_clusters - (nclusters + rsv + dirty_clusters) <
556 EXT4_FREECLUSTERS_WATERMARK) {
557 free_clusters = percpu_counter_sum_positive(fcc);
558 dirty_clusters = percpu_counter_sum_positive(dcc);
559 }
560 /* Check whether we have space after accounting for current
561 * dirty clusters & root reserved clusters.
562 */
563 if (free_clusters >= (rsv + nclusters + dirty_clusters))
564 return 1;
565
566 /* Hm, nope. Are (enough) root reserved clusters available? */
567 if (uid_eq(sbi->s_resuid, current_fsuid()) ||
568 (!gid_eq(sbi->s_resgid, GLOBAL_ROOT_GID) && in_group_p(sbi->s_resgid)) ||
569 capable(CAP_SYS_RESOURCE) ||
570 (flags & EXT4_MB_USE_ROOT_BLOCKS)) {
571
572 if (free_clusters >= (nclusters + dirty_clusters +
573 resv_clusters))
574 return 1;
575 }
576 /* No free blocks. Let's see if we can dip into reserved pool */
577 if (flags & EXT4_MB_USE_RESERVED) {
578 if (free_clusters >= (nclusters + dirty_clusters))
579 return 1;
580 }
581
582 return 0;
583}
584
585int ext4_claim_free_clusters(struct ext4_sb_info *sbi,
586 s64 nclusters, unsigned int flags)
587{
588 if (ext4_has_free_clusters(sbi, nclusters, flags)) {
589 percpu_counter_add(&sbi->s_dirtyclusters_counter, nclusters);
590 return 0;
591 } else
592 return -ENOSPC;
593}
594
595/**
596 * ext4_should_retry_alloc()
597 * @sb: super block
598 * @retries number of attemps has been made
599 *
600 * ext4_should_retry_alloc() is called when ENOSPC is returned, and if
601 * it is profitable to retry the operation, this function will wait
602 * for the current or committing transaction to complete, and then
603 * return TRUE.
604 *
605 * if the total number of retries exceed three times, return FALSE.
606 */
607int ext4_should_retry_alloc(struct super_block *sb, int *retries)
608{
609 if (!ext4_has_free_clusters(EXT4_SB(sb), 1, 0) ||
610 (*retries)++ > 3 ||
611 !EXT4_SB(sb)->s_journal)
612 return 0;
613
614 jbd_debug(1, "%s: retrying operation after ENOSPC\n", sb->s_id);
615
616 smp_mb();
617 if (EXT4_SB(sb)->s_mb_free_pending)
618 jbd2_journal_force_commit_nested(EXT4_SB(sb)->s_journal);
619 return 1;
620}
621
622/*
623 * ext4_new_meta_blocks() -- allocate block for meta data (indexing) blocks
624 *
625 * @handle: handle to this transaction
626 * @inode: file inode
627 * @goal: given target block(filesystem wide)
628 * @count: pointer to total number of clusters needed
629 * @errp: error code
630 *
631 * Return 1st allocated block number on success, *count stores total account
632 * error stores in errp pointer
633 */
634ext4_fsblk_t ext4_new_meta_blocks(handle_t *handle, struct inode *inode,
635 ext4_fsblk_t goal, unsigned int flags,
636 unsigned long *count, int *errp)
637{
638 struct ext4_allocation_request ar;
639 ext4_fsblk_t ret;
640
641 memset(&ar, 0, sizeof(ar));
642 /* Fill with neighbour allocated blocks */
643 ar.inode = inode;
644 ar.goal = goal;
645 ar.len = count ? *count : 1;
646 ar.flags = flags;
647
648 ret = ext4_mb_new_blocks(handle, &ar, errp);
649 if (count)
650 *count = ar.len;
651 /*
652 * Account for the allocated meta blocks. We will never
653 * fail EDQUOT for metdata, but we do account for it.
654 */
655 if (!(*errp) && (flags & EXT4_MB_DELALLOC_RESERVED)) {
656 dquot_alloc_block_nofail(inode,
657 EXT4_C2B(EXT4_SB(inode->i_sb), ar.len));
658 }
659 return ret;
660}
661
662/**
663 * ext4_count_free_clusters() -- count filesystem free clusters
664 * @sb: superblock
665 *
666 * Adds up the number of free clusters from each block group.
667 */
668ext4_fsblk_t ext4_count_free_clusters(struct super_block *sb)
669{
670 ext4_fsblk_t desc_count;
671 struct ext4_group_desc *gdp;
672 ext4_group_t i;
673 ext4_group_t ngroups = ext4_get_groups_count(sb);
674 struct ext4_group_info *grp;
675#ifdef EXT4FS_DEBUG
676 struct ext4_super_block *es;
677 ext4_fsblk_t bitmap_count;
678 unsigned int x;
679 struct buffer_head *bitmap_bh = NULL;
680
681 es = EXT4_SB(sb)->s_es;
682 desc_count = 0;
683 bitmap_count = 0;
684 gdp = NULL;
685
686 for (i = 0; i < ngroups; i++) {
687 gdp = ext4_get_group_desc(sb, i, NULL);
688 if (!gdp)
689 continue;
690 grp = NULL;
691 if (EXT4_SB(sb)->s_group_info)
692 grp = ext4_get_group_info(sb, i);
693 if (!grp || !EXT4_MB_GRP_BBITMAP_CORRUPT(grp))
694 desc_count += ext4_free_group_clusters(sb, gdp);
695 brelse(bitmap_bh);
696 bitmap_bh = ext4_read_block_bitmap(sb, i);
697 if (IS_ERR(bitmap_bh)) {
698 bitmap_bh = NULL;
699 continue;
700 }
701
702 x = ext4_count_free(bitmap_bh->b_data,
703 EXT4_CLUSTERS_PER_GROUP(sb) / 8);
704 printk(KERN_DEBUG "group %u: stored = %d, counted = %u\n",
705 i, ext4_free_group_clusters(sb, gdp), x);
706 bitmap_count += x;
707 }
708 brelse(bitmap_bh);
709 printk(KERN_DEBUG "ext4_count_free_clusters: stored = %llu"
710 ", computed = %llu, %llu\n",
711 EXT4_NUM_B2C(EXT4_SB(sb), ext4_free_blocks_count(es)),
712 desc_count, bitmap_count);
713 return bitmap_count;
714#else
715 desc_count = 0;
716 for (i = 0; i < ngroups; i++) {
717 gdp = ext4_get_group_desc(sb, i, NULL);
718 if (!gdp)
719 continue;
720 grp = NULL;
721 if (EXT4_SB(sb)->s_group_info)
722 grp = ext4_get_group_info(sb, i);
723 if (!grp || !EXT4_MB_GRP_BBITMAP_CORRUPT(grp))
724 desc_count += ext4_free_group_clusters(sb, gdp);
725 }
726
727 return desc_count;
728#endif
729}
730
731static inline int test_root(ext4_group_t a, int b)
732{
733 while (1) {
734 if (a < b)
735 return 0;
736 if (a == b)
737 return 1;
738 if ((a % b) != 0)
739 return 0;
740 a = a / b;
741 }
742}
743
744/**
745 * ext4_bg_has_super - number of blocks used by the superblock in group
746 * @sb: superblock for filesystem
747 * @group: group number to check
748 *
749 * Return the number of blocks used by the superblock (primary or backup)
750 * in this group. Currently this will be only 0 or 1.
751 */
752int ext4_bg_has_super(struct super_block *sb, ext4_group_t group)
753{
754 struct ext4_super_block *es = EXT4_SB(sb)->s_es;
755
756 if (group == 0)
757 return 1;
758 if (ext4_has_feature_sparse_super2(sb)) {
759 if (group == le32_to_cpu(es->s_backup_bgs[0]) ||
760 group == le32_to_cpu(es->s_backup_bgs[1]))
761 return 1;
762 return 0;
763 }
764 if ((group <= 1) || !ext4_has_feature_sparse_super(sb))
765 return 1;
766 if (!(group & 1))
767 return 0;
768 if (test_root(group, 3) || (test_root(group, 5)) ||
769 test_root(group, 7))
770 return 1;
771
772 return 0;
773}
774
775static unsigned long ext4_bg_num_gdb_meta(struct super_block *sb,
776 ext4_group_t group)
777{
778 unsigned long metagroup = group / EXT4_DESC_PER_BLOCK(sb);
779 ext4_group_t first = metagroup * EXT4_DESC_PER_BLOCK(sb);
780 ext4_group_t last = first + EXT4_DESC_PER_BLOCK(sb) - 1;
781
782 if (group == first || group == first + 1 || group == last)
783 return 1;
784 return 0;
785}
786
787static unsigned long ext4_bg_num_gdb_nometa(struct super_block *sb,
788 ext4_group_t group)
789{
790 if (!ext4_bg_has_super(sb, group))
791 return 0;
792
793 if (ext4_has_feature_meta_bg(sb))
794 return le32_to_cpu(EXT4_SB(sb)->s_es->s_first_meta_bg);
795 else
796 return EXT4_SB(sb)->s_gdb_count;
797}
798
799/**
800 * ext4_bg_num_gdb - number of blocks used by the group table in group
801 * @sb: superblock for filesystem
802 * @group: group number to check
803 *
804 * Return the number of blocks used by the group descriptor table
805 * (primary or backup) in this group. In the future there may be a
806 * different number of descriptor blocks in each group.
807 */
808unsigned long ext4_bg_num_gdb(struct super_block *sb, ext4_group_t group)
809{
810 unsigned long first_meta_bg =
811 le32_to_cpu(EXT4_SB(sb)->s_es->s_first_meta_bg);
812 unsigned long metagroup = group / EXT4_DESC_PER_BLOCK(sb);
813
814 if (!ext4_has_feature_meta_bg(sb) || metagroup < first_meta_bg)
815 return ext4_bg_num_gdb_nometa(sb, group);
816
817 return ext4_bg_num_gdb_meta(sb,group);
818
819}
820
821/*
822 * This function returns the number of file system metadata clusters at
823 * the beginning of a block group, including the reserved gdt blocks.
824 */
825static unsigned ext4_num_base_meta_clusters(struct super_block *sb,
826 ext4_group_t block_group)
827{
828 struct ext4_sb_info *sbi = EXT4_SB(sb);
829 unsigned num;
830
831 /* Check for superblock and gdt backups in this group */
832 num = ext4_bg_has_super(sb, block_group);
833
834 if (!ext4_has_feature_meta_bg(sb) ||
835 block_group < le32_to_cpu(sbi->s_es->s_first_meta_bg) *
836 sbi->s_desc_per_block) {
837 if (num) {
838 num += ext4_bg_num_gdb(sb, block_group);
839 num += le16_to_cpu(sbi->s_es->s_reserved_gdt_blocks);
840 }
841 } else { /* For META_BG_BLOCK_GROUPS */
842 num += ext4_bg_num_gdb(sb, block_group);
843 }
844 return EXT4_NUM_B2C(sbi, num);
845}
846/**
847 * ext4_inode_to_goal_block - return a hint for block allocation
848 * @inode: inode for block allocation
849 *
850 * Return the ideal location to start allocating blocks for a
851 * newly created inode.
852 */
853ext4_fsblk_t ext4_inode_to_goal_block(struct inode *inode)
854{
855 struct ext4_inode_info *ei = EXT4_I(inode);
856 ext4_group_t block_group;
857 ext4_grpblk_t colour;
858 int flex_size = ext4_flex_bg_size(EXT4_SB(inode->i_sb));
859 ext4_fsblk_t bg_start;
860 ext4_fsblk_t last_block;
861
862 block_group = ei->i_block_group;
863 if (flex_size >= EXT4_FLEX_SIZE_DIR_ALLOC_SCHEME) {
864 /*
865 * If there are at least EXT4_FLEX_SIZE_DIR_ALLOC_SCHEME
866 * block groups per flexgroup, reserve the first block
867 * group for directories and special files. Regular
868 * files will start at the second block group. This
869 * tends to speed up directory access and improves
870 * fsck times.
871 */
872 block_group &= ~(flex_size-1);
873 if (S_ISREG(inode->i_mode))
874 block_group++;
875 }
876 bg_start = ext4_group_first_block_no(inode->i_sb, block_group);
877 last_block = ext4_blocks_count(EXT4_SB(inode->i_sb)->s_es) - 1;
878
879 /*
880 * If we are doing delayed allocation, we don't need take
881 * colour into account.
882 */
883 if (test_opt(inode->i_sb, DELALLOC))
884 return bg_start;
885
886 if (bg_start + EXT4_BLOCKS_PER_GROUP(inode->i_sb) <= last_block)
887 colour = (current->pid % 16) *
888 (EXT4_BLOCKS_PER_GROUP(inode->i_sb) / 16);
889 else
890 colour = (current->pid % 16) * ((last_block - bg_start) / 16);
891 return bg_start + colour;
892}
893
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * linux/fs/ext4/balloc.c
4 *
5 * Copyright (C) 1992, 1993, 1994, 1995
6 * Remy Card (card@masi.ibp.fr)
7 * Laboratoire MASI - Institut Blaise Pascal
8 * Universite Pierre et Marie Curie (Paris VI)
9 *
10 * Enhanced block allocation by Stephen Tweedie (sct@redhat.com), 1993
11 * Big-endian to little-endian byte-swapping/bitmaps by
12 * David S. Miller (davem@caip.rutgers.edu), 1995
13 */
14
15#include <linux/time.h>
16#include <linux/capability.h>
17#include <linux/fs.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 */
86static unsigned 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 */
179static int ext4_init_block_bitmap(struct super_block *sb,
180 struct buffer_head *bh,
181 ext4_group_t block_group,
182 struct ext4_group_desc *gdp)
183{
184 unsigned int bit, bit_max;
185 struct ext4_sb_info *sbi = EXT4_SB(sb);
186 ext4_fsblk_t start, tmp;
187
188 ASSERT(buffer_locked(bh));
189
190 /* If checksum is bad mark all blocks used to prevent allocation
191 * essentially implementing a per-group read-only flag. */
192 if (!ext4_group_desc_csum_verify(sb, block_group, gdp)) {
193 ext4_mark_group_bitmap_corrupted(sb, block_group,
194 EXT4_GROUP_INFO_BBITMAP_CORRUPT |
195 EXT4_GROUP_INFO_IBITMAP_CORRUPT);
196 return -EFSBADCRC;
197 }
198 memset(bh->b_data, 0, sb->s_blocksize);
199
200 bit_max = ext4_num_base_meta_clusters(sb, block_group);
201 if ((bit_max >> 3) >= bh->b_size)
202 return -EFSCORRUPTED;
203
204 for (bit = 0; bit < bit_max; bit++)
205 ext4_set_bit(bit, bh->b_data);
206
207 start = ext4_group_first_block_no(sb, block_group);
208
209 /* Set bits for block and inode bitmaps, and inode table */
210 tmp = ext4_block_bitmap(sb, gdp);
211 if (ext4_block_in_group(sb, tmp, block_group))
212 ext4_set_bit(EXT4_B2C(sbi, tmp - start), bh->b_data);
213
214 tmp = ext4_inode_bitmap(sb, gdp);
215 if (ext4_block_in_group(sb, tmp, block_group))
216 ext4_set_bit(EXT4_B2C(sbi, tmp - start), bh->b_data);
217
218 tmp = ext4_inode_table(sb, gdp);
219 for (; tmp < ext4_inode_table(sb, gdp) +
220 sbi->s_itb_per_group; tmp++) {
221 if (ext4_block_in_group(sb, tmp, block_group))
222 ext4_set_bit(EXT4_B2C(sbi, tmp - start), bh->b_data);
223 }
224
225 /*
226 * Also if the number of blocks within the group is less than
227 * the blocksize * 8 ( which is the size of bitmap ), set rest
228 * of the block bitmap to 1
229 */
230 ext4_mark_bitmap_end(num_clusters_in_group(sb, block_group),
231 sb->s_blocksize * 8, bh->b_data);
232 return 0;
233}
234
235/* Return the number of free blocks in a block group. It is used when
236 * the block bitmap is uninitialized, so we can't just count the bits
237 * in the bitmap. */
238unsigned ext4_free_clusters_after_init(struct super_block *sb,
239 ext4_group_t block_group,
240 struct ext4_group_desc *gdp)
241{
242 return num_clusters_in_group(sb, block_group) -
243 ext4_num_overhead_clusters(sb, block_group, gdp);
244}
245
246/*
247 * The free blocks are managed by bitmaps. A file system contains several
248 * blocks groups. Each group contains 1 bitmap block for blocks, 1 bitmap
249 * block for inodes, N blocks for the inode table and data blocks.
250 *
251 * The file system contains group descriptors which are located after the
252 * super block. Each descriptor contains the number of the bitmap block and
253 * the free blocks count in the block. The descriptors are loaded in memory
254 * when a file system is mounted (see ext4_fill_super).
255 */
256
257/**
258 * ext4_get_group_desc() -- load group descriptor from disk
259 * @sb: super block
260 * @block_group: given block group
261 * @bh: pointer to the buffer head to store the block
262 * group descriptor
263 */
264struct ext4_group_desc * ext4_get_group_desc(struct super_block *sb,
265 ext4_group_t block_group,
266 struct buffer_head **bh)
267{
268 unsigned int group_desc;
269 unsigned int offset;
270 ext4_group_t ngroups = ext4_get_groups_count(sb);
271 struct ext4_group_desc *desc;
272 struct ext4_sb_info *sbi = EXT4_SB(sb);
273 struct buffer_head *bh_p;
274
275 if (block_group >= ngroups) {
276 ext4_error(sb, "block_group >= groups_count - block_group = %u,"
277 " groups_count = %u", block_group, ngroups);
278
279 return NULL;
280 }
281
282 group_desc = block_group >> EXT4_DESC_PER_BLOCK_BITS(sb);
283 offset = block_group & (EXT4_DESC_PER_BLOCK(sb) - 1);
284 bh_p = sbi_array_rcu_deref(sbi, s_group_desc, group_desc);
285 /*
286 * sbi_array_rcu_deref returns with rcu unlocked, this is ok since
287 * the pointer being dereferenced won't be dereferenced again. By
288 * looking at the usage in add_new_gdb() the value isn't modified,
289 * just the pointer, and so it remains valid.
290 */
291 if (!bh_p) {
292 ext4_error(sb, "Group descriptor not loaded - "
293 "block_group = %u, group_desc = %u, desc = %u",
294 block_group, group_desc, offset);
295 return NULL;
296 }
297
298 desc = (struct ext4_group_desc *)(
299 (__u8 *)bh_p->b_data +
300 offset * EXT4_DESC_SIZE(sb));
301 if (bh)
302 *bh = bh_p;
303 return desc;
304}
305
306/*
307 * Return the block number which was discovered to be invalid, or 0 if
308 * the block bitmap is valid.
309 */
310static ext4_fsblk_t ext4_valid_block_bitmap(struct super_block *sb,
311 struct ext4_group_desc *desc,
312 ext4_group_t block_group,
313 struct buffer_head *bh)
314{
315 struct ext4_sb_info *sbi = EXT4_SB(sb);
316 ext4_grpblk_t offset;
317 ext4_grpblk_t next_zero_bit;
318 ext4_grpblk_t max_bit = EXT4_CLUSTERS_PER_GROUP(sb);
319 ext4_fsblk_t blk;
320 ext4_fsblk_t group_first_block;
321
322 if (ext4_has_feature_flex_bg(sb)) {
323 /* with FLEX_BG, the inode/block bitmaps and itable
324 * blocks may not be in the group at all
325 * so the bitmap validation will be skipped for those groups
326 * or it has to also read the block group where the bitmaps
327 * are located to verify they are set.
328 */
329 return 0;
330 }
331 group_first_block = ext4_group_first_block_no(sb, block_group);
332
333 /* check whether block bitmap block number is set */
334 blk = ext4_block_bitmap(sb, desc);
335 offset = blk - group_first_block;
336 if (offset < 0 || EXT4_B2C(sbi, offset) >= max_bit ||
337 !ext4_test_bit(EXT4_B2C(sbi, offset), bh->b_data))
338 /* bad block bitmap */
339 return blk;
340
341 /* check whether the inode bitmap block number is set */
342 blk = ext4_inode_bitmap(sb, desc);
343 offset = blk - group_first_block;
344 if (offset < 0 || EXT4_B2C(sbi, offset) >= max_bit ||
345 !ext4_test_bit(EXT4_B2C(sbi, offset), bh->b_data))
346 /* bad block bitmap */
347 return blk;
348
349 /* check whether the inode table block number is set */
350 blk = ext4_inode_table(sb, desc);
351 offset = blk - group_first_block;
352 if (offset < 0 || EXT4_B2C(sbi, offset) >= max_bit ||
353 EXT4_B2C(sbi, offset + sbi->s_itb_per_group) >= max_bit)
354 return blk;
355 next_zero_bit = ext4_find_next_zero_bit(bh->b_data,
356 EXT4_B2C(sbi, offset + sbi->s_itb_per_group),
357 EXT4_B2C(sbi, offset));
358 if (next_zero_bit <
359 EXT4_B2C(sbi, offset + sbi->s_itb_per_group))
360 /* bad bitmap for inode tables */
361 return blk;
362 return 0;
363}
364
365static int ext4_validate_block_bitmap(struct super_block *sb,
366 struct ext4_group_desc *desc,
367 ext4_group_t block_group,
368 struct buffer_head *bh)
369{
370 ext4_fsblk_t blk;
371 struct ext4_group_info *grp;
372
373 if (EXT4_SB(sb)->s_mount_state & EXT4_FC_REPLAY)
374 return 0;
375
376 grp = ext4_get_group_info(sb, block_group);
377
378 if (buffer_verified(bh))
379 return 0;
380 if (EXT4_MB_GRP_BBITMAP_CORRUPT(grp))
381 return -EFSCORRUPTED;
382
383 ext4_lock_group(sb, block_group);
384 if (buffer_verified(bh))
385 goto verified;
386 if (unlikely(!ext4_block_bitmap_csum_verify(sb, block_group,
387 desc, bh) ||
388 ext4_simulate_fail(sb, EXT4_SIM_BBITMAP_CRC))) {
389 ext4_unlock_group(sb, block_group);
390 ext4_error(sb, "bg %u: bad block bitmap checksum", block_group);
391 ext4_mark_group_bitmap_corrupted(sb, block_group,
392 EXT4_GROUP_INFO_BBITMAP_CORRUPT);
393 return -EFSBADCRC;
394 }
395 blk = ext4_valid_block_bitmap(sb, desc, block_group, bh);
396 if (unlikely(blk != 0)) {
397 ext4_unlock_group(sb, block_group);
398 ext4_error(sb, "bg %u: block %llu: invalid block bitmap",
399 block_group, blk);
400 ext4_mark_group_bitmap_corrupted(sb, block_group,
401 EXT4_GROUP_INFO_BBITMAP_CORRUPT);
402 return -EFSCORRUPTED;
403 }
404 set_buffer_verified(bh);
405verified:
406 ext4_unlock_group(sb, block_group);
407 return 0;
408}
409
410/**
411 * ext4_read_block_bitmap_nowait()
412 * @sb: super block
413 * @block_group: given block group
414 *
415 * Read the bitmap for a given block_group,and validate the
416 * bits for block/inode/inode tables are set in the bitmaps
417 *
418 * Return buffer_head on success or an ERR_PTR in case of failure.
419 */
420struct buffer_head *
421ext4_read_block_bitmap_nowait(struct super_block *sb, ext4_group_t block_group,
422 bool ignore_locked)
423{
424 struct ext4_group_desc *desc;
425 struct ext4_sb_info *sbi = EXT4_SB(sb);
426 struct buffer_head *bh;
427 ext4_fsblk_t bitmap_blk;
428 int err;
429
430 desc = ext4_get_group_desc(sb, block_group, NULL);
431 if (!desc)
432 return ERR_PTR(-EFSCORRUPTED);
433 bitmap_blk = ext4_block_bitmap(sb, desc);
434 if ((bitmap_blk <= le32_to_cpu(sbi->s_es->s_first_data_block)) ||
435 (bitmap_blk >= ext4_blocks_count(sbi->s_es))) {
436 ext4_error(sb, "Invalid block bitmap block %llu in "
437 "block_group %u", bitmap_blk, block_group);
438 ext4_mark_group_bitmap_corrupted(sb, block_group,
439 EXT4_GROUP_INFO_BBITMAP_CORRUPT);
440 return ERR_PTR(-EFSCORRUPTED);
441 }
442 bh = sb_getblk(sb, bitmap_blk);
443 if (unlikely(!bh)) {
444 ext4_warning(sb, "Cannot get buffer for block bitmap - "
445 "block_group = %u, block_bitmap = %llu",
446 block_group, bitmap_blk);
447 return ERR_PTR(-ENOMEM);
448 }
449
450 if (ignore_locked && buffer_locked(bh)) {
451 /* buffer under IO already, return if called for prefetching */
452 put_bh(bh);
453 return NULL;
454 }
455
456 if (bitmap_uptodate(bh))
457 goto verify;
458
459 lock_buffer(bh);
460 if (bitmap_uptodate(bh)) {
461 unlock_buffer(bh);
462 goto verify;
463 }
464 ext4_lock_group(sb, block_group);
465 if (ext4_has_group_desc_csum(sb) &&
466 (desc->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT))) {
467 if (block_group == 0) {
468 ext4_unlock_group(sb, block_group);
469 unlock_buffer(bh);
470 ext4_error(sb, "Block bitmap for bg 0 marked "
471 "uninitialized");
472 err = -EFSCORRUPTED;
473 goto out;
474 }
475 err = ext4_init_block_bitmap(sb, bh, block_group, desc);
476 set_bitmap_uptodate(bh);
477 set_buffer_uptodate(bh);
478 set_buffer_verified(bh);
479 ext4_unlock_group(sb, block_group);
480 unlock_buffer(bh);
481 if (err) {
482 ext4_error(sb, "Failed to init block bitmap for group "
483 "%u: %d", block_group, err);
484 goto out;
485 }
486 goto verify;
487 }
488 ext4_unlock_group(sb, block_group);
489 if (buffer_uptodate(bh)) {
490 /*
491 * if not uninit if bh is uptodate,
492 * bitmap is also uptodate
493 */
494 set_bitmap_uptodate(bh);
495 unlock_buffer(bh);
496 goto verify;
497 }
498 /*
499 * submit the buffer_head for reading
500 */
501 set_buffer_new(bh);
502 trace_ext4_read_block_bitmap_load(sb, block_group, ignore_locked);
503 ext4_read_bh_nowait(bh, REQ_META | REQ_PRIO |
504 (ignore_locked ? REQ_RAHEAD : 0),
505 ext4_end_bitmap_read);
506 return bh;
507verify:
508 err = ext4_validate_block_bitmap(sb, desc, block_group, bh);
509 if (err)
510 goto out;
511 return bh;
512out:
513 put_bh(bh);
514 return ERR_PTR(err);
515}
516
517/* Returns 0 on success, -errno on error */
518int ext4_wait_block_bitmap(struct super_block *sb, ext4_group_t block_group,
519 struct buffer_head *bh)
520{
521 struct ext4_group_desc *desc;
522
523 if (!buffer_new(bh))
524 return 0;
525 desc = ext4_get_group_desc(sb, block_group, NULL);
526 if (!desc)
527 return -EFSCORRUPTED;
528 wait_on_buffer(bh);
529 ext4_simulate_fail_bh(sb, bh, EXT4_SIM_BBITMAP_EIO);
530 if (!buffer_uptodate(bh)) {
531 ext4_error_err(sb, EIO, "Cannot read block bitmap - "
532 "block_group = %u, block_bitmap = %llu",
533 block_group, (unsigned long long) bh->b_blocknr);
534 ext4_mark_group_bitmap_corrupted(sb, block_group,
535 EXT4_GROUP_INFO_BBITMAP_CORRUPT);
536 return -EIO;
537 }
538 clear_buffer_new(bh);
539 /* Panic or remount fs read-only if block bitmap is invalid */
540 return ext4_validate_block_bitmap(sb, desc, block_group, bh);
541}
542
543struct buffer_head *
544ext4_read_block_bitmap(struct super_block *sb, ext4_group_t block_group)
545{
546 struct buffer_head *bh;
547 int err;
548
549 bh = ext4_read_block_bitmap_nowait(sb, block_group, false);
550 if (IS_ERR(bh))
551 return bh;
552 err = ext4_wait_block_bitmap(sb, block_group, bh);
553 if (err) {
554 put_bh(bh);
555 return ERR_PTR(err);
556 }
557 return bh;
558}
559
560/**
561 * ext4_has_free_clusters()
562 * @sbi: in-core super block structure.
563 * @nclusters: number of needed blocks
564 * @flags: flags from ext4_mb_new_blocks()
565 *
566 * Check if filesystem has nclusters free & available for allocation.
567 * On success return 1, return 0 on failure.
568 */
569static int ext4_has_free_clusters(struct ext4_sb_info *sbi,
570 s64 nclusters, unsigned int flags)
571{
572 s64 free_clusters, dirty_clusters, rsv, resv_clusters;
573 struct percpu_counter *fcc = &sbi->s_freeclusters_counter;
574 struct percpu_counter *dcc = &sbi->s_dirtyclusters_counter;
575
576 free_clusters = percpu_counter_read_positive(fcc);
577 dirty_clusters = percpu_counter_read_positive(dcc);
578 resv_clusters = atomic64_read(&sbi->s_resv_clusters);
579
580 /*
581 * r_blocks_count should always be multiple of the cluster ratio so
582 * we are safe to do a plane bit shift only.
583 */
584 rsv = (ext4_r_blocks_count(sbi->s_es) >> sbi->s_cluster_bits) +
585 resv_clusters;
586
587 if (free_clusters - (nclusters + rsv + dirty_clusters) <
588 EXT4_FREECLUSTERS_WATERMARK) {
589 free_clusters = percpu_counter_sum_positive(fcc);
590 dirty_clusters = percpu_counter_sum_positive(dcc);
591 }
592 /* Check whether we have space after accounting for current
593 * dirty clusters & root reserved clusters.
594 */
595 if (free_clusters >= (rsv + nclusters + dirty_clusters))
596 return 1;
597
598 /* Hm, nope. Are (enough) root reserved clusters available? */
599 if (uid_eq(sbi->s_resuid, current_fsuid()) ||
600 (!gid_eq(sbi->s_resgid, GLOBAL_ROOT_GID) && in_group_p(sbi->s_resgid)) ||
601 capable(CAP_SYS_RESOURCE) ||
602 (flags & EXT4_MB_USE_ROOT_BLOCKS)) {
603
604 if (free_clusters >= (nclusters + dirty_clusters +
605 resv_clusters))
606 return 1;
607 }
608 /* No free blocks. Let's see if we can dip into reserved pool */
609 if (flags & EXT4_MB_USE_RESERVED) {
610 if (free_clusters >= (nclusters + dirty_clusters))
611 return 1;
612 }
613
614 return 0;
615}
616
617int ext4_claim_free_clusters(struct ext4_sb_info *sbi,
618 s64 nclusters, unsigned int flags)
619{
620 if (ext4_has_free_clusters(sbi, nclusters, flags)) {
621 percpu_counter_add(&sbi->s_dirtyclusters_counter, nclusters);
622 return 0;
623 } else
624 return -ENOSPC;
625}
626
627/**
628 * ext4_should_retry_alloc() - check if a block allocation should be retried
629 * @sb: superblock
630 * @retries: number of retry attempts made so far
631 *
632 * ext4_should_retry_alloc() is called when ENOSPC is returned while
633 * attempting to allocate blocks. If there's an indication that a pending
634 * journal transaction might free some space and allow another attempt to
635 * succeed, this function will wait for the current or committing transaction
636 * to complete and then return TRUE.
637 */
638int ext4_should_retry_alloc(struct super_block *sb, int *retries)
639{
640 struct ext4_sb_info *sbi = EXT4_SB(sb);
641
642 if (!sbi->s_journal)
643 return 0;
644
645 if (++(*retries) > 3) {
646 percpu_counter_inc(&sbi->s_sra_exceeded_retry_limit);
647 return 0;
648 }
649
650 /*
651 * if there's no indication that blocks are about to be freed it's
652 * possible we just missed a transaction commit that did so
653 */
654 smp_mb();
655 if (sbi->s_mb_free_pending == 0)
656 return ext4_has_free_clusters(sbi, 1, 0);
657
658 /*
659 * it's possible we've just missed a transaction commit here,
660 * so ignore the returned status
661 */
662 jbd_debug(1, "%s: retrying operation after ENOSPC\n", sb->s_id);
663 (void) jbd2_journal_force_commit_nested(sbi->s_journal);
664 return 1;
665}
666
667/*
668 * ext4_new_meta_blocks() -- allocate block for meta data (indexing) blocks
669 *
670 * @handle: handle to this transaction
671 * @inode: file inode
672 * @goal: given target block(filesystem wide)
673 * @count: pointer to total number of clusters needed
674 * @errp: error code
675 *
676 * Return 1st allocated block number on success, *count stores total account
677 * error stores in errp pointer
678 */
679ext4_fsblk_t ext4_new_meta_blocks(handle_t *handle, struct inode *inode,
680 ext4_fsblk_t goal, unsigned int flags,
681 unsigned long *count, int *errp)
682{
683 struct ext4_allocation_request ar;
684 ext4_fsblk_t ret;
685
686 memset(&ar, 0, sizeof(ar));
687 /* Fill with neighbour allocated blocks */
688 ar.inode = inode;
689 ar.goal = goal;
690 ar.len = count ? *count : 1;
691 ar.flags = flags;
692
693 ret = ext4_mb_new_blocks(handle, &ar, errp);
694 if (count)
695 *count = ar.len;
696 /*
697 * Account for the allocated meta blocks. We will never
698 * fail EDQUOT for metdata, but we do account for it.
699 */
700 if (!(*errp) && (flags & EXT4_MB_DELALLOC_RESERVED)) {
701 dquot_alloc_block_nofail(inode,
702 EXT4_C2B(EXT4_SB(inode->i_sb), ar.len));
703 }
704 return ret;
705}
706
707/**
708 * ext4_count_free_clusters() -- count filesystem free clusters
709 * @sb: superblock
710 *
711 * Adds up the number of free clusters from each block group.
712 */
713ext4_fsblk_t ext4_count_free_clusters(struct super_block *sb)
714{
715 ext4_fsblk_t desc_count;
716 struct ext4_group_desc *gdp;
717 ext4_group_t i;
718 ext4_group_t ngroups = ext4_get_groups_count(sb);
719 struct ext4_group_info *grp;
720#ifdef EXT4FS_DEBUG
721 struct ext4_super_block *es;
722 ext4_fsblk_t bitmap_count;
723 unsigned int x;
724 struct buffer_head *bitmap_bh = NULL;
725
726 es = EXT4_SB(sb)->s_es;
727 desc_count = 0;
728 bitmap_count = 0;
729 gdp = NULL;
730
731 for (i = 0; i < ngroups; i++) {
732 gdp = ext4_get_group_desc(sb, i, NULL);
733 if (!gdp)
734 continue;
735 grp = NULL;
736 if (EXT4_SB(sb)->s_group_info)
737 grp = ext4_get_group_info(sb, i);
738 if (!grp || !EXT4_MB_GRP_BBITMAP_CORRUPT(grp))
739 desc_count += ext4_free_group_clusters(sb, gdp);
740 brelse(bitmap_bh);
741 bitmap_bh = ext4_read_block_bitmap(sb, i);
742 if (IS_ERR(bitmap_bh)) {
743 bitmap_bh = NULL;
744 continue;
745 }
746
747 x = ext4_count_free(bitmap_bh->b_data,
748 EXT4_CLUSTERS_PER_GROUP(sb) / 8);
749 printk(KERN_DEBUG "group %u: stored = %d, counted = %u\n",
750 i, ext4_free_group_clusters(sb, gdp), x);
751 bitmap_count += x;
752 }
753 brelse(bitmap_bh);
754 printk(KERN_DEBUG "ext4_count_free_clusters: stored = %llu"
755 ", computed = %llu, %llu\n",
756 EXT4_NUM_B2C(EXT4_SB(sb), ext4_free_blocks_count(es)),
757 desc_count, bitmap_count);
758 return bitmap_count;
759#else
760 desc_count = 0;
761 for (i = 0; i < ngroups; i++) {
762 gdp = ext4_get_group_desc(sb, i, NULL);
763 if (!gdp)
764 continue;
765 grp = NULL;
766 if (EXT4_SB(sb)->s_group_info)
767 grp = ext4_get_group_info(sb, i);
768 if (!grp || !EXT4_MB_GRP_BBITMAP_CORRUPT(grp))
769 desc_count += ext4_free_group_clusters(sb, gdp);
770 }
771
772 return desc_count;
773#endif
774}
775
776static inline int test_root(ext4_group_t a, int b)
777{
778 while (1) {
779 if (a < b)
780 return 0;
781 if (a == b)
782 return 1;
783 if ((a % b) != 0)
784 return 0;
785 a = a / b;
786 }
787}
788
789/**
790 * ext4_bg_has_super - number of blocks used by the superblock in group
791 * @sb: superblock for filesystem
792 * @group: group number to check
793 *
794 * Return the number of blocks used by the superblock (primary or backup)
795 * in this group. Currently this will be only 0 or 1.
796 */
797int ext4_bg_has_super(struct super_block *sb, ext4_group_t group)
798{
799 struct ext4_super_block *es = EXT4_SB(sb)->s_es;
800
801 if (group == 0)
802 return 1;
803 if (ext4_has_feature_sparse_super2(sb)) {
804 if (group == le32_to_cpu(es->s_backup_bgs[0]) ||
805 group == le32_to_cpu(es->s_backup_bgs[1]))
806 return 1;
807 return 0;
808 }
809 if ((group <= 1) || !ext4_has_feature_sparse_super(sb))
810 return 1;
811 if (!(group & 1))
812 return 0;
813 if (test_root(group, 3) || (test_root(group, 5)) ||
814 test_root(group, 7))
815 return 1;
816
817 return 0;
818}
819
820static unsigned long ext4_bg_num_gdb_meta(struct super_block *sb,
821 ext4_group_t group)
822{
823 unsigned long metagroup = group / EXT4_DESC_PER_BLOCK(sb);
824 ext4_group_t first = metagroup * EXT4_DESC_PER_BLOCK(sb);
825 ext4_group_t last = first + EXT4_DESC_PER_BLOCK(sb) - 1;
826
827 if (group == first || group == first + 1 || group == last)
828 return 1;
829 return 0;
830}
831
832static unsigned long ext4_bg_num_gdb_nometa(struct super_block *sb,
833 ext4_group_t group)
834{
835 if (!ext4_bg_has_super(sb, group))
836 return 0;
837
838 if (ext4_has_feature_meta_bg(sb))
839 return le32_to_cpu(EXT4_SB(sb)->s_es->s_first_meta_bg);
840 else
841 return EXT4_SB(sb)->s_gdb_count;
842}
843
844/**
845 * ext4_bg_num_gdb - number of blocks used by the group table in group
846 * @sb: superblock for filesystem
847 * @group: group number to check
848 *
849 * Return the number of blocks used by the group descriptor table
850 * (primary or backup) in this group. In the future there may be a
851 * different number of descriptor blocks in each group.
852 */
853unsigned long ext4_bg_num_gdb(struct super_block *sb, ext4_group_t group)
854{
855 unsigned long first_meta_bg =
856 le32_to_cpu(EXT4_SB(sb)->s_es->s_first_meta_bg);
857 unsigned long metagroup = group / EXT4_DESC_PER_BLOCK(sb);
858
859 if (!ext4_has_feature_meta_bg(sb) || metagroup < first_meta_bg)
860 return ext4_bg_num_gdb_nometa(sb, group);
861
862 return ext4_bg_num_gdb_meta(sb,group);
863
864}
865
866/*
867 * This function returns the number of file system metadata clusters at
868 * the beginning of a block group, including the reserved gdt blocks.
869 */
870static unsigned ext4_num_base_meta_clusters(struct super_block *sb,
871 ext4_group_t block_group)
872{
873 struct ext4_sb_info *sbi = EXT4_SB(sb);
874 unsigned num;
875
876 /* Check for superblock and gdt backups in this group */
877 num = ext4_bg_has_super(sb, block_group);
878
879 if (!ext4_has_feature_meta_bg(sb) ||
880 block_group < le32_to_cpu(sbi->s_es->s_first_meta_bg) *
881 sbi->s_desc_per_block) {
882 if (num) {
883 num += ext4_bg_num_gdb(sb, block_group);
884 num += le16_to_cpu(sbi->s_es->s_reserved_gdt_blocks);
885 }
886 } else { /* For META_BG_BLOCK_GROUPS */
887 num += ext4_bg_num_gdb(sb, block_group);
888 }
889 return EXT4_NUM_B2C(sbi, num);
890}
891/**
892 * ext4_inode_to_goal_block - return a hint for block allocation
893 * @inode: inode for block allocation
894 *
895 * Return the ideal location to start allocating blocks for a
896 * newly created inode.
897 */
898ext4_fsblk_t ext4_inode_to_goal_block(struct inode *inode)
899{
900 struct ext4_inode_info *ei = EXT4_I(inode);
901 ext4_group_t block_group;
902 ext4_grpblk_t colour;
903 int flex_size = ext4_flex_bg_size(EXT4_SB(inode->i_sb));
904 ext4_fsblk_t bg_start;
905 ext4_fsblk_t last_block;
906
907 block_group = ei->i_block_group;
908 if (flex_size >= EXT4_FLEX_SIZE_DIR_ALLOC_SCHEME) {
909 /*
910 * If there are at least EXT4_FLEX_SIZE_DIR_ALLOC_SCHEME
911 * block groups per flexgroup, reserve the first block
912 * group for directories and special files. Regular
913 * files will start at the second block group. This
914 * tends to speed up directory access and improves
915 * fsck times.
916 */
917 block_group &= ~(flex_size-1);
918 if (S_ISREG(inode->i_mode))
919 block_group++;
920 }
921 bg_start = ext4_group_first_block_no(inode->i_sb, block_group);
922 last_block = ext4_blocks_count(EXT4_SB(inode->i_sb)->s_es) - 1;
923
924 /*
925 * If we are doing delayed allocation, we don't need take
926 * colour into account.
927 */
928 if (test_opt(inode->i_sb, DELALLOC))
929 return bg_start;
930
931 if (bg_start + EXT4_BLOCKS_PER_GROUP(inode->i_sb) <= last_block)
932 colour = (task_pid_nr(current) % 16) *
933 (EXT4_BLOCKS_PER_GROUP(inode->i_sb) / 16);
934 else
935 colour = (task_pid_nr(current) % 16) *
936 ((last_block - bg_start) / 16);
937 return bg_start + colour;
938}
939