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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 for (bit = 0; bit < bit_max; bit++)
212 ext4_set_bit(bit, bh->b_data);
213
214 start = ext4_group_first_block_no(sb, block_group);
215
216 if (ext4_has_feature_flex_bg(sb))
217 flex_bg = 1;
218
219 /* Set bits for block and inode bitmaps, and inode table */
220 tmp = ext4_block_bitmap(sb, gdp);
221 if (!flex_bg || ext4_block_in_group(sb, tmp, block_group))
222 ext4_set_bit(EXT4_B2C(sbi, tmp - start), bh->b_data);
223
224 tmp = ext4_inode_bitmap(sb, gdp);
225 if (!flex_bg || ext4_block_in_group(sb, tmp, block_group))
226 ext4_set_bit(EXT4_B2C(sbi, tmp - start), bh->b_data);
227
228 tmp = ext4_inode_table(sb, gdp);
229 for (; tmp < ext4_inode_table(sb, gdp) +
230 sbi->s_itb_per_group; tmp++) {
231 if (!flex_bg || ext4_block_in_group(sb, tmp, block_group))
232 ext4_set_bit(EXT4_B2C(sbi, tmp - start), bh->b_data);
233 }
234
235 /*
236 * Also if the number of blocks within the group is less than
237 * the blocksize * 8 ( which is the size of bitmap ), set rest
238 * of the block bitmap to 1
239 */
240 ext4_mark_bitmap_end(num_clusters_in_group(sb, block_group),
241 sb->s_blocksize * 8, bh->b_data);
242 ext4_block_bitmap_csum_set(sb, block_group, gdp, bh);
243 ext4_group_desc_csum_set(sb, block_group, gdp);
244 return 0;
245}
246
247/* Return the number of free blocks in a block group. It is used when
248 * the block bitmap is uninitialized, so we can't just count the bits
249 * in the bitmap. */
250unsigned ext4_free_clusters_after_init(struct super_block *sb,
251 ext4_group_t block_group,
252 struct ext4_group_desc *gdp)
253{
254 return num_clusters_in_group(sb, block_group) -
255 ext4_num_overhead_clusters(sb, block_group, gdp);
256}
257
258/*
259 * The free blocks are managed by bitmaps. A file system contains several
260 * blocks groups. Each group contains 1 bitmap block for blocks, 1 bitmap
261 * block for inodes, N blocks for the inode table and data blocks.
262 *
263 * The file system contains group descriptors which are located after the
264 * super block. Each descriptor contains the number of the bitmap block and
265 * the free blocks count in the block. The descriptors are loaded in memory
266 * when a file system is mounted (see ext4_fill_super).
267 */
268
269/**
270 * ext4_get_group_desc() -- load group descriptor from disk
271 * @sb: super block
272 * @block_group: given block group
273 * @bh: pointer to the buffer head to store the block
274 * group descriptor
275 */
276struct ext4_group_desc * ext4_get_group_desc(struct super_block *sb,
277 ext4_group_t block_group,
278 struct buffer_head **bh)
279{
280 unsigned int group_desc;
281 unsigned int offset;
282 ext4_group_t ngroups = ext4_get_groups_count(sb);
283 struct ext4_group_desc *desc;
284 struct ext4_sb_info *sbi = EXT4_SB(sb);
285
286 if (block_group >= ngroups) {
287 ext4_error(sb, "block_group >= groups_count - block_group = %u,"
288 " groups_count = %u", block_group, ngroups);
289
290 return NULL;
291 }
292
293 group_desc = block_group >> EXT4_DESC_PER_BLOCK_BITS(sb);
294 offset = block_group & (EXT4_DESC_PER_BLOCK(sb) - 1);
295 if (!sbi->s_group_desc[group_desc]) {
296 ext4_error(sb, "Group descriptor not loaded - "
297 "block_group = %u, group_desc = %u, desc = %u",
298 block_group, group_desc, offset);
299 return NULL;
300 }
301
302 desc = (struct ext4_group_desc *)(
303 (__u8 *)sbi->s_group_desc[group_desc]->b_data +
304 offset * EXT4_DESC_SIZE(sb));
305 if (bh)
306 *bh = sbi->s_group_desc[group_desc];
307 return desc;
308}
309
310/*
311 * Return the block number which was discovered to be invalid, or 0 if
312 * the block bitmap is valid.
313 */
314static ext4_fsblk_t ext4_valid_block_bitmap(struct super_block *sb,
315 struct ext4_group_desc *desc,
316 ext4_group_t block_group,
317 struct buffer_head *bh)
318{
319 struct ext4_sb_info *sbi = EXT4_SB(sb);
320 ext4_grpblk_t offset;
321 ext4_grpblk_t next_zero_bit;
322 ext4_fsblk_t blk;
323 ext4_fsblk_t group_first_block;
324
325 if (ext4_has_feature_flex_bg(sb)) {
326 /* with FLEX_BG, the inode/block bitmaps and itable
327 * blocks may not be in the group at all
328 * so the bitmap validation will be skipped for those groups
329 * or it has to also read the block group where the bitmaps
330 * are located to verify they are set.
331 */
332 return 0;
333 }
334 group_first_block = ext4_group_first_block_no(sb, block_group);
335
336 /* check whether block bitmap block number is set */
337 blk = ext4_block_bitmap(sb, desc);
338 offset = blk - group_first_block;
339 if (!ext4_test_bit(EXT4_B2C(sbi, offset), bh->b_data))
340 /* bad block bitmap */
341 return blk;
342
343 /* check whether the inode bitmap block number is set */
344 blk = ext4_inode_bitmap(sb, desc);
345 offset = blk - group_first_block;
346 if (!ext4_test_bit(EXT4_B2C(sbi, offset), bh->b_data))
347 /* bad block bitmap */
348 return blk;
349
350 /* check whether the inode table block number is set */
351 blk = ext4_inode_table(sb, desc);
352 offset = blk - group_first_block;
353 next_zero_bit = ext4_find_next_zero_bit(bh->b_data,
354 EXT4_B2C(sbi, offset + EXT4_SB(sb)->s_itb_per_group),
355 EXT4_B2C(sbi, offset));
356 if (next_zero_bit <
357 EXT4_B2C(sbi, offset + EXT4_SB(sb)->s_itb_per_group))
358 /* bad bitmap for inode tables */
359 return blk;
360 return 0;
361}
362
363static int ext4_validate_block_bitmap(struct super_block *sb,
364 struct ext4_group_desc *desc,
365 ext4_group_t block_group,
366 struct buffer_head *bh)
367{
368 ext4_fsblk_t blk;
369 struct ext4_group_info *grp = ext4_get_group_info(sb, block_group);
370 struct ext4_sb_info *sbi = EXT4_SB(sb);
371
372 if (buffer_verified(bh))
373 return 0;
374 if (EXT4_MB_GRP_BBITMAP_CORRUPT(grp))
375 return -EFSCORRUPTED;
376
377 ext4_lock_group(sb, block_group);
378 if (unlikely(!ext4_block_bitmap_csum_verify(sb, block_group,
379 desc, bh))) {
380 ext4_unlock_group(sb, block_group);
381 ext4_error(sb, "bg %u: bad block bitmap checksum", block_group);
382 if (!EXT4_MB_GRP_BBITMAP_CORRUPT(grp))
383 percpu_counter_sub(&sbi->s_freeclusters_counter,
384 grp->bb_free);
385 set_bit(EXT4_GROUP_INFO_BBITMAP_CORRUPT_BIT, &grp->bb_state);
386 return -EFSBADCRC;
387 }
388 blk = ext4_valid_block_bitmap(sb, desc, block_group, bh);
389 if (unlikely(blk != 0)) {
390 ext4_unlock_group(sb, block_group);
391 ext4_error(sb, "bg %u: block %llu: invalid block bitmap",
392 block_group, blk);
393 if (!EXT4_MB_GRP_BBITMAP_CORRUPT(grp))
394 percpu_counter_sub(&sbi->s_freeclusters_counter,
395 grp->bb_free);
396 set_bit(EXT4_GROUP_INFO_BBITMAP_CORRUPT_BIT, &grp->bb_state);
397 return -EFSCORRUPTED;
398 }
399 set_buffer_verified(bh);
400 ext4_unlock_group(sb, block_group);
401 return 0;
402}
403
404/**
405 * ext4_read_block_bitmap_nowait()
406 * @sb: super block
407 * @block_group: given block group
408 *
409 * Read the bitmap for a given block_group,and validate the
410 * bits for block/inode/inode tables are set in the bitmaps
411 *
412 * Return buffer_head on success or NULL in case of failure.
413 */
414struct buffer_head *
415ext4_read_block_bitmap_nowait(struct super_block *sb, ext4_group_t block_group)
416{
417 struct ext4_group_desc *desc;
418 struct buffer_head *bh;
419 ext4_fsblk_t bitmap_blk;
420 int err;
421
422 desc = ext4_get_group_desc(sb, block_group, NULL);
423 if (!desc)
424 return ERR_PTR(-EFSCORRUPTED);
425 bitmap_blk = ext4_block_bitmap(sb, desc);
426 bh = sb_getblk(sb, bitmap_blk);
427 if (unlikely(!bh)) {
428 ext4_error(sb, "Cannot get buffer for block bitmap - "
429 "block_group = %u, block_bitmap = %llu",
430 block_group, bitmap_blk);
431 return ERR_PTR(-ENOMEM);
432 }
433
434 if (bitmap_uptodate(bh))
435 goto verify;
436
437 lock_buffer(bh);
438 if (bitmap_uptodate(bh)) {
439 unlock_buffer(bh);
440 goto verify;
441 }
442 ext4_lock_group(sb, block_group);
443 if (desc->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) {
444 err = ext4_init_block_bitmap(sb, bh, block_group, desc);
445 set_bitmap_uptodate(bh);
446 set_buffer_uptodate(bh);
447 ext4_unlock_group(sb, block_group);
448 unlock_buffer(bh);
449 if (err) {
450 ext4_error(sb, "Failed to init block bitmap for group "
451 "%u: %d", block_group, err);
452 goto out;
453 }
454 goto verify;
455 }
456 ext4_unlock_group(sb, block_group);
457 if (buffer_uptodate(bh)) {
458 /*
459 * if not uninit if bh is uptodate,
460 * bitmap is also uptodate
461 */
462 set_bitmap_uptodate(bh);
463 unlock_buffer(bh);
464 goto verify;
465 }
466 /*
467 * submit the buffer_head for reading
468 */
469 set_buffer_new(bh);
470 trace_ext4_read_block_bitmap_load(sb, block_group);
471 bh->b_end_io = ext4_end_bitmap_read;
472 get_bh(bh);
473 submit_bh(READ | REQ_META | REQ_PRIO, bh);
474 return bh;
475verify:
476 err = ext4_validate_block_bitmap(sb, desc, block_group, bh);
477 if (err)
478 goto out;
479 return bh;
480out:
481 put_bh(bh);
482 return ERR_PTR(err);
483}
484
485/* Returns 0 on success, 1 on error */
486int ext4_wait_block_bitmap(struct super_block *sb, ext4_group_t block_group,
487 struct buffer_head *bh)
488{
489 struct ext4_group_desc *desc;
490
491 if (!buffer_new(bh))
492 return 0;
493 desc = ext4_get_group_desc(sb, block_group, NULL);
494 if (!desc)
495 return -EFSCORRUPTED;
496 wait_on_buffer(bh);
497 if (!buffer_uptodate(bh)) {
498 ext4_error(sb, "Cannot read block bitmap - "
499 "block_group = %u, block_bitmap = %llu",
500 block_group, (unsigned long long) bh->b_blocknr);
501 return -EIO;
502 }
503 clear_buffer_new(bh);
504 /* Panic or remount fs read-only if block bitmap is invalid */
505 return ext4_validate_block_bitmap(sb, desc, block_group, bh);
506}
507
508struct buffer_head *
509ext4_read_block_bitmap(struct super_block *sb, ext4_group_t block_group)
510{
511 struct buffer_head *bh;
512 int err;
513
514 bh = ext4_read_block_bitmap_nowait(sb, block_group);
515 if (IS_ERR(bh))
516 return bh;
517 err = ext4_wait_block_bitmap(sb, block_group, bh);
518 if (err) {
519 put_bh(bh);
520 return ERR_PTR(err);
521 }
522 return bh;
523}
524
525/**
526 * ext4_has_free_clusters()
527 * @sbi: in-core super block structure.
528 * @nclusters: number of needed blocks
529 * @flags: flags from ext4_mb_new_blocks()
530 *
531 * Check if filesystem has nclusters free & available for allocation.
532 * On success return 1, return 0 on failure.
533 */
534static int ext4_has_free_clusters(struct ext4_sb_info *sbi,
535 s64 nclusters, unsigned int flags)
536{
537 s64 free_clusters, dirty_clusters, rsv, resv_clusters;
538 struct percpu_counter *fcc = &sbi->s_freeclusters_counter;
539 struct percpu_counter *dcc = &sbi->s_dirtyclusters_counter;
540
541 free_clusters = percpu_counter_read_positive(fcc);
542 dirty_clusters = percpu_counter_read_positive(dcc);
543 resv_clusters = atomic64_read(&sbi->s_resv_clusters);
544
545 /*
546 * r_blocks_count should always be multiple of the cluster ratio so
547 * we are safe to do a plane bit shift only.
548 */
549 rsv = (ext4_r_blocks_count(sbi->s_es) >> sbi->s_cluster_bits) +
550 resv_clusters;
551
552 if (free_clusters - (nclusters + rsv + dirty_clusters) <
553 EXT4_FREECLUSTERS_WATERMARK) {
554 free_clusters = percpu_counter_sum_positive(fcc);
555 dirty_clusters = percpu_counter_sum_positive(dcc);
556 }
557 /* Check whether we have space after accounting for current
558 * dirty clusters & root reserved clusters.
559 */
560 if (free_clusters >= (rsv + nclusters + dirty_clusters))
561 return 1;
562
563 /* Hm, nope. Are (enough) root reserved clusters available? */
564 if (uid_eq(sbi->s_resuid, current_fsuid()) ||
565 (!gid_eq(sbi->s_resgid, GLOBAL_ROOT_GID) && in_group_p(sbi->s_resgid)) ||
566 capable(CAP_SYS_RESOURCE) ||
567 (flags & EXT4_MB_USE_ROOT_BLOCKS)) {
568
569 if (free_clusters >= (nclusters + dirty_clusters +
570 resv_clusters))
571 return 1;
572 }
573 /* No free blocks. Let's see if we can dip into reserved pool */
574 if (flags & EXT4_MB_USE_RESERVED) {
575 if (free_clusters >= (nclusters + dirty_clusters))
576 return 1;
577 }
578
579 return 0;
580}
581
582int ext4_claim_free_clusters(struct ext4_sb_info *sbi,
583 s64 nclusters, unsigned int flags)
584{
585 if (ext4_has_free_clusters(sbi, nclusters, flags)) {
586 percpu_counter_add(&sbi->s_dirtyclusters_counter, nclusters);
587 return 0;
588 } else
589 return -ENOSPC;
590}
591
592/**
593 * ext4_should_retry_alloc()
594 * @sb: super block
595 * @retries number of attemps has been made
596 *
597 * ext4_should_retry_alloc() is called when ENOSPC is returned, and if
598 * it is profitable to retry the operation, this function will wait
599 * for the current or committing transaction to complete, and then
600 * return TRUE.
601 *
602 * if the total number of retries exceed three times, return FALSE.
603 */
604int ext4_should_retry_alloc(struct super_block *sb, int *retries)
605{
606 if (!ext4_has_free_clusters(EXT4_SB(sb), 1, 0) ||
607 (*retries)++ > 3 ||
608 !EXT4_SB(sb)->s_journal)
609 return 0;
610
611 jbd_debug(1, "%s: retrying operation after ENOSPC\n", sb->s_id);
612
613 return jbd2_journal_force_commit_nested(EXT4_SB(sb)->s_journal);
614}
615
616/*
617 * ext4_new_meta_blocks() -- allocate block for meta data (indexing) blocks
618 *
619 * @handle: handle to this transaction
620 * @inode: file inode
621 * @goal: given target block(filesystem wide)
622 * @count: pointer to total number of clusters needed
623 * @errp: error code
624 *
625 * Return 1st allocated block number on success, *count stores total account
626 * error stores in errp pointer
627 */
628ext4_fsblk_t ext4_new_meta_blocks(handle_t *handle, struct inode *inode,
629 ext4_fsblk_t goal, unsigned int flags,
630 unsigned long *count, int *errp)
631{
632 struct ext4_allocation_request ar;
633 ext4_fsblk_t ret;
634
635 memset(&ar, 0, sizeof(ar));
636 /* Fill with neighbour allocated blocks */
637 ar.inode = inode;
638 ar.goal = goal;
639 ar.len = count ? *count : 1;
640 ar.flags = flags;
641
642 ret = ext4_mb_new_blocks(handle, &ar, errp);
643 if (count)
644 *count = ar.len;
645 /*
646 * Account for the allocated meta blocks. We will never
647 * fail EDQUOT for metdata, but we do account for it.
648 */
649 if (!(*errp) && (flags & EXT4_MB_DELALLOC_RESERVED)) {
650 dquot_alloc_block_nofail(inode,
651 EXT4_C2B(EXT4_SB(inode->i_sb), ar.len));
652 }
653 return ret;
654}
655
656/**
657 * ext4_count_free_clusters() -- count filesystem free clusters
658 * @sb: superblock
659 *
660 * Adds up the number of free clusters from each block group.
661 */
662ext4_fsblk_t ext4_count_free_clusters(struct super_block *sb)
663{
664 ext4_fsblk_t desc_count;
665 struct ext4_group_desc *gdp;
666 ext4_group_t i;
667 ext4_group_t ngroups = ext4_get_groups_count(sb);
668 struct ext4_group_info *grp;
669#ifdef EXT4FS_DEBUG
670 struct ext4_super_block *es;
671 ext4_fsblk_t bitmap_count;
672 unsigned int x;
673 struct buffer_head *bitmap_bh = NULL;
674
675 es = EXT4_SB(sb)->s_es;
676 desc_count = 0;
677 bitmap_count = 0;
678 gdp = NULL;
679
680 for (i = 0; i < ngroups; i++) {
681 gdp = ext4_get_group_desc(sb, i, NULL);
682 if (!gdp)
683 continue;
684 grp = NULL;
685 if (EXT4_SB(sb)->s_group_info)
686 grp = ext4_get_group_info(sb, i);
687 if (!grp || !EXT4_MB_GRP_BBITMAP_CORRUPT(grp))
688 desc_count += ext4_free_group_clusters(sb, gdp);
689 brelse(bitmap_bh);
690 bitmap_bh = ext4_read_block_bitmap(sb, i);
691 if (IS_ERR(bitmap_bh)) {
692 bitmap_bh = NULL;
693 continue;
694 }
695
696 x = ext4_count_free(bitmap_bh->b_data,
697 EXT4_CLUSTERS_PER_GROUP(sb) / 8);
698 printk(KERN_DEBUG "group %u: stored = %d, counted = %u\n",
699 i, ext4_free_group_clusters(sb, gdp), x);
700 bitmap_count += x;
701 }
702 brelse(bitmap_bh);
703 printk(KERN_DEBUG "ext4_count_free_clusters: stored = %llu"
704 ", computed = %llu, %llu\n",
705 EXT4_NUM_B2C(EXT4_SB(sb), ext4_free_blocks_count(es)),
706 desc_count, bitmap_count);
707 return bitmap_count;
708#else
709 desc_count = 0;
710 for (i = 0; i < ngroups; i++) {
711 gdp = ext4_get_group_desc(sb, i, NULL);
712 if (!gdp)
713 continue;
714 grp = NULL;
715 if (EXT4_SB(sb)->s_group_info)
716 grp = ext4_get_group_info(sb, i);
717 if (!grp || !EXT4_MB_GRP_BBITMAP_CORRUPT(grp))
718 desc_count += ext4_free_group_clusters(sb, gdp);
719 }
720
721 return desc_count;
722#endif
723}
724
725static inline int test_root(ext4_group_t a, int b)
726{
727 while (1) {
728 if (a < b)
729 return 0;
730 if (a == b)
731 return 1;
732 if ((a % b) != 0)
733 return 0;
734 a = a / b;
735 }
736}
737
738/**
739 * ext4_bg_has_super - number of blocks used by the superblock in group
740 * @sb: superblock for filesystem
741 * @group: group number to check
742 *
743 * Return the number of blocks used by the superblock (primary or backup)
744 * in this group. Currently this will be only 0 or 1.
745 */
746int ext4_bg_has_super(struct super_block *sb, ext4_group_t group)
747{
748 struct ext4_super_block *es = EXT4_SB(sb)->s_es;
749
750 if (group == 0)
751 return 1;
752 if (ext4_has_feature_sparse_super2(sb)) {
753 if (group == le32_to_cpu(es->s_backup_bgs[0]) ||
754 group == le32_to_cpu(es->s_backup_bgs[1]))
755 return 1;
756 return 0;
757 }
758 if ((group <= 1) || !ext4_has_feature_sparse_super(sb))
759 return 1;
760 if (!(group & 1))
761 return 0;
762 if (test_root(group, 3) || (test_root(group, 5)) ||
763 test_root(group, 7))
764 return 1;
765
766 return 0;
767}
768
769static unsigned long ext4_bg_num_gdb_meta(struct super_block *sb,
770 ext4_group_t group)
771{
772 unsigned long metagroup = group / EXT4_DESC_PER_BLOCK(sb);
773 ext4_group_t first = metagroup * EXT4_DESC_PER_BLOCK(sb);
774 ext4_group_t last = first + EXT4_DESC_PER_BLOCK(sb) - 1;
775
776 if (group == first || group == first + 1 || group == last)
777 return 1;
778 return 0;
779}
780
781static unsigned long ext4_bg_num_gdb_nometa(struct super_block *sb,
782 ext4_group_t group)
783{
784 if (!ext4_bg_has_super(sb, group))
785 return 0;
786
787 if (ext4_has_feature_meta_bg(sb))
788 return le32_to_cpu(EXT4_SB(sb)->s_es->s_first_meta_bg);
789 else
790 return EXT4_SB(sb)->s_gdb_count;
791}
792
793/**
794 * ext4_bg_num_gdb - number of blocks used by the group table in group
795 * @sb: superblock for filesystem
796 * @group: group number to check
797 *
798 * Return the number of blocks used by the group descriptor table
799 * (primary or backup) in this group. In the future there may be a
800 * different number of descriptor blocks in each group.
801 */
802unsigned long ext4_bg_num_gdb(struct super_block *sb, ext4_group_t group)
803{
804 unsigned long first_meta_bg =
805 le32_to_cpu(EXT4_SB(sb)->s_es->s_first_meta_bg);
806 unsigned long metagroup = group / EXT4_DESC_PER_BLOCK(sb);
807
808 if (!ext4_has_feature_meta_bg(sb) || metagroup < first_meta_bg)
809 return ext4_bg_num_gdb_nometa(sb, group);
810
811 return ext4_bg_num_gdb_meta(sb,group);
812
813}
814
815/*
816 * This function returns the number of file system metadata clusters at
817 * the beginning of a block group, including the reserved gdt blocks.
818 */
819static unsigned ext4_num_base_meta_clusters(struct super_block *sb,
820 ext4_group_t block_group)
821{
822 struct ext4_sb_info *sbi = EXT4_SB(sb);
823 unsigned num;
824
825 /* Check for superblock and gdt backups in this group */
826 num = ext4_bg_has_super(sb, block_group);
827
828 if (!ext4_has_feature_meta_bg(sb) ||
829 block_group < le32_to_cpu(sbi->s_es->s_first_meta_bg) *
830 sbi->s_desc_per_block) {
831 if (num) {
832 num += ext4_bg_num_gdb(sb, block_group);
833 num += le16_to_cpu(sbi->s_es->s_reserved_gdt_blocks);
834 }
835 } else { /* For META_BG_BLOCK_GROUPS */
836 num += ext4_bg_num_gdb(sb, block_group);
837 }
838 return EXT4_NUM_B2C(sbi, num);
839}
840/**
841 * ext4_inode_to_goal_block - return a hint for block allocation
842 * @inode: inode for block allocation
843 *
844 * Return the ideal location to start allocating blocks for a
845 * newly created inode.
846 */
847ext4_fsblk_t ext4_inode_to_goal_block(struct inode *inode)
848{
849 struct ext4_inode_info *ei = EXT4_I(inode);
850 ext4_group_t block_group;
851 ext4_grpblk_t colour;
852 int flex_size = ext4_flex_bg_size(EXT4_SB(inode->i_sb));
853 ext4_fsblk_t bg_start;
854 ext4_fsblk_t last_block;
855
856 block_group = ei->i_block_group;
857 if (flex_size >= EXT4_FLEX_SIZE_DIR_ALLOC_SCHEME) {
858 /*
859 * If there are at least EXT4_FLEX_SIZE_DIR_ALLOC_SCHEME
860 * block groups per flexgroup, reserve the first block
861 * group for directories and special files. Regular
862 * files will start at the second block group. This
863 * tends to speed up directory access and improves
864 * fsck times.
865 */
866 block_group &= ~(flex_size-1);
867 if (S_ISREG(inode->i_mode))
868 block_group++;
869 }
870 bg_start = ext4_group_first_block_no(inode->i_sb, block_group);
871 last_block = ext4_blocks_count(EXT4_SB(inode->i_sb)->s_es) - 1;
872
873 /*
874 * If we are doing delayed allocation, we don't need take
875 * colour into account.
876 */
877 if (test_opt(inode->i_sb, DELALLOC))
878 return bg_start;
879
880 if (bg_start + EXT4_BLOCKS_PER_GROUP(inode->i_sb) <= last_block)
881 colour = (current->pid % 16) *
882 (EXT4_BLOCKS_PER_GROUP(inode->i_sb) / 16);
883 else
884 colour = (current->pid % 16) * ((last_block - bg_start) / 16);
885 return bg_start + colour;
886}
887
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 J_ASSERT_BH(bh, 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
274 if (block_group >= ngroups) {
275 ext4_error(sb, "block_group >= groups_count - block_group = %u,"
276 " groups_count = %u", block_group, ngroups);
277
278 return NULL;
279 }
280
281 group_desc = block_group >> EXT4_DESC_PER_BLOCK_BITS(sb);
282 offset = block_group & (EXT4_DESC_PER_BLOCK(sb) - 1);
283 if (!sbi->s_group_desc[group_desc]) {
284 ext4_error(sb, "Group descriptor not loaded - "
285 "block_group = %u, group_desc = %u, desc = %u",
286 block_group, group_desc, offset);
287 return NULL;
288 }
289
290 desc = (struct ext4_group_desc *)(
291 (__u8 *)sbi->s_group_desc[group_desc]->b_data +
292 offset * EXT4_DESC_SIZE(sb));
293 if (bh)
294 *bh = sbi->s_group_desc[group_desc];
295 return desc;
296}
297
298/*
299 * Return the block number which was discovered to be invalid, or 0 if
300 * the block bitmap is valid.
301 */
302static ext4_fsblk_t ext4_valid_block_bitmap(struct super_block *sb,
303 struct ext4_group_desc *desc,
304 ext4_group_t block_group,
305 struct buffer_head *bh)
306{
307 struct ext4_sb_info *sbi = EXT4_SB(sb);
308 ext4_grpblk_t offset;
309 ext4_grpblk_t next_zero_bit;
310 ext4_grpblk_t max_bit = EXT4_CLUSTERS_PER_GROUP(sb);
311 ext4_fsblk_t blk;
312 ext4_fsblk_t group_first_block;
313
314 if (ext4_has_feature_flex_bg(sb)) {
315 /* with FLEX_BG, the inode/block bitmaps and itable
316 * blocks may not be in the group at all
317 * so the bitmap validation will be skipped for those groups
318 * or it has to also read the block group where the bitmaps
319 * are located to verify they are set.
320 */
321 return 0;
322 }
323 group_first_block = ext4_group_first_block_no(sb, block_group);
324
325 /* check whether block bitmap block number is set */
326 blk = ext4_block_bitmap(sb, desc);
327 offset = blk - group_first_block;
328 if (offset < 0 || EXT4_B2C(sbi, offset) >= max_bit ||
329 !ext4_test_bit(EXT4_B2C(sbi, 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 (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 table block number is set */
342 blk = ext4_inode_table(sb, desc);
343 offset = blk - group_first_block;
344 if (offset < 0 || EXT4_B2C(sbi, offset) >= max_bit ||
345 EXT4_B2C(sbi, offset + sbi->s_itb_per_group) >= max_bit)
346 return blk;
347 next_zero_bit = ext4_find_next_zero_bit(bh->b_data,
348 EXT4_B2C(sbi, offset + sbi->s_itb_per_group),
349 EXT4_B2C(sbi, offset));
350 if (next_zero_bit <
351 EXT4_B2C(sbi, offset + sbi->s_itb_per_group))
352 /* bad bitmap for inode tables */
353 return blk;
354 return 0;
355}
356
357static int ext4_validate_block_bitmap(struct super_block *sb,
358 struct ext4_group_desc *desc,
359 ext4_group_t block_group,
360 struct buffer_head *bh)
361{
362 ext4_fsblk_t blk;
363 struct ext4_group_info *grp = ext4_get_group_info(sb, block_group);
364
365 if (buffer_verified(bh))
366 return 0;
367 if (EXT4_MB_GRP_BBITMAP_CORRUPT(grp))
368 return -EFSCORRUPTED;
369
370 ext4_lock_group(sb, block_group);
371 if (buffer_verified(bh))
372 goto verified;
373 if (unlikely(!ext4_block_bitmap_csum_verify(sb, block_group,
374 desc, bh))) {
375 ext4_unlock_group(sb, block_group);
376 ext4_error(sb, "bg %u: bad block bitmap checksum", block_group);
377 ext4_mark_group_bitmap_corrupted(sb, block_group,
378 EXT4_GROUP_INFO_BBITMAP_CORRUPT);
379 return -EFSBADCRC;
380 }
381 blk = ext4_valid_block_bitmap(sb, desc, block_group, bh);
382 if (unlikely(blk != 0)) {
383 ext4_unlock_group(sb, block_group);
384 ext4_error(sb, "bg %u: block %llu: invalid block bitmap",
385 block_group, blk);
386 ext4_mark_group_bitmap_corrupted(sb, block_group,
387 EXT4_GROUP_INFO_BBITMAP_CORRUPT);
388 return -EFSCORRUPTED;
389 }
390 set_buffer_verified(bh);
391verified:
392 ext4_unlock_group(sb, block_group);
393 return 0;
394}
395
396/**
397 * ext4_read_block_bitmap_nowait()
398 * @sb: super block
399 * @block_group: given block group
400 *
401 * Read the bitmap for a given block_group,and validate the
402 * bits for block/inode/inode tables are set in the bitmaps
403 *
404 * Return buffer_head on success or NULL in case of failure.
405 */
406struct buffer_head *
407ext4_read_block_bitmap_nowait(struct super_block *sb, ext4_group_t block_group)
408{
409 struct ext4_group_desc *desc;
410 struct ext4_sb_info *sbi = EXT4_SB(sb);
411 struct buffer_head *bh;
412 ext4_fsblk_t bitmap_blk;
413 int err;
414
415 desc = ext4_get_group_desc(sb, block_group, NULL);
416 if (!desc)
417 return ERR_PTR(-EFSCORRUPTED);
418 bitmap_blk = ext4_block_bitmap(sb, desc);
419 if ((bitmap_blk <= le32_to_cpu(sbi->s_es->s_first_data_block)) ||
420 (bitmap_blk >= ext4_blocks_count(sbi->s_es))) {
421 ext4_error(sb, "Invalid block bitmap block %llu in "
422 "block_group %u", bitmap_blk, block_group);
423 ext4_mark_group_bitmap_corrupted(sb, block_group,
424 EXT4_GROUP_INFO_BBITMAP_CORRUPT);
425 return ERR_PTR(-EFSCORRUPTED);
426 }
427 bh = sb_getblk(sb, bitmap_blk);
428 if (unlikely(!bh)) {
429 ext4_warning(sb, "Cannot get buffer for block bitmap - "
430 "block_group = %u, block_bitmap = %llu",
431 block_group, bitmap_blk);
432 return ERR_PTR(-ENOMEM);
433 }
434
435 if (bitmap_uptodate(bh))
436 goto verify;
437
438 lock_buffer(bh);
439 if (bitmap_uptodate(bh)) {
440 unlock_buffer(bh);
441 goto verify;
442 }
443 ext4_lock_group(sb, block_group);
444 if (ext4_has_group_desc_csum(sb) &&
445 (desc->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT))) {
446 if (block_group == 0) {
447 ext4_unlock_group(sb, block_group);
448 unlock_buffer(bh);
449 ext4_error(sb, "Block bitmap for bg 0 marked "
450 "uninitialized");
451 err = -EFSCORRUPTED;
452 goto out;
453 }
454 err = ext4_init_block_bitmap(sb, bh, block_group, desc);
455 set_bitmap_uptodate(bh);
456 set_buffer_uptodate(bh);
457 set_buffer_verified(bh);
458 ext4_unlock_group(sb, block_group);
459 unlock_buffer(bh);
460 if (err) {
461 ext4_error(sb, "Failed to init block bitmap for group "
462 "%u: %d", block_group, err);
463 goto out;
464 }
465 goto verify;
466 }
467 ext4_unlock_group(sb, block_group);
468 if (buffer_uptodate(bh)) {
469 /*
470 * if not uninit if bh is uptodate,
471 * bitmap is also uptodate
472 */
473 set_bitmap_uptodate(bh);
474 unlock_buffer(bh);
475 goto verify;
476 }
477 /*
478 * submit the buffer_head for reading
479 */
480 set_buffer_new(bh);
481 trace_ext4_read_block_bitmap_load(sb, block_group);
482 bh->b_end_io = ext4_end_bitmap_read;
483 get_bh(bh);
484 submit_bh(REQ_OP_READ, REQ_META | REQ_PRIO, bh);
485 return bh;
486verify:
487 err = ext4_validate_block_bitmap(sb, desc, block_group, bh);
488 if (err)
489 goto out;
490 return bh;
491out:
492 put_bh(bh);
493 return ERR_PTR(err);
494}
495
496/* Returns 0 on success, 1 on error */
497int ext4_wait_block_bitmap(struct super_block *sb, ext4_group_t block_group,
498 struct buffer_head *bh)
499{
500 struct ext4_group_desc *desc;
501
502 if (!buffer_new(bh))
503 return 0;
504 desc = ext4_get_group_desc(sb, block_group, NULL);
505 if (!desc)
506 return -EFSCORRUPTED;
507 wait_on_buffer(bh);
508 if (!buffer_uptodate(bh)) {
509 ext4_error(sb, "Cannot read block bitmap - "
510 "block_group = %u, block_bitmap = %llu",
511 block_group, (unsigned long long) bh->b_blocknr);
512 ext4_mark_group_bitmap_corrupted(sb, block_group,
513 EXT4_GROUP_INFO_BBITMAP_CORRUPT);
514 return -EIO;
515 }
516 clear_buffer_new(bh);
517 /* Panic or remount fs read-only if block bitmap is invalid */
518 return ext4_validate_block_bitmap(sb, desc, block_group, bh);
519}
520
521struct buffer_head *
522ext4_read_block_bitmap(struct super_block *sb, ext4_group_t block_group)
523{
524 struct buffer_head *bh;
525 int err;
526
527 bh = ext4_read_block_bitmap_nowait(sb, block_group);
528 if (IS_ERR(bh))
529 return bh;
530 err = ext4_wait_block_bitmap(sb, block_group, bh);
531 if (err) {
532 put_bh(bh);
533 return ERR_PTR(err);
534 }
535 return bh;
536}
537
538/**
539 * ext4_has_free_clusters()
540 * @sbi: in-core super block structure.
541 * @nclusters: number of needed blocks
542 * @flags: flags from ext4_mb_new_blocks()
543 *
544 * Check if filesystem has nclusters free & available for allocation.
545 * On success return 1, return 0 on failure.
546 */
547static int ext4_has_free_clusters(struct ext4_sb_info *sbi,
548 s64 nclusters, unsigned int flags)
549{
550 s64 free_clusters, dirty_clusters, rsv, resv_clusters;
551 struct percpu_counter *fcc = &sbi->s_freeclusters_counter;
552 struct percpu_counter *dcc = &sbi->s_dirtyclusters_counter;
553
554 free_clusters = percpu_counter_read_positive(fcc);
555 dirty_clusters = percpu_counter_read_positive(dcc);
556 resv_clusters = atomic64_read(&sbi->s_resv_clusters);
557
558 /*
559 * r_blocks_count should always be multiple of the cluster ratio so
560 * we are safe to do a plane bit shift only.
561 */
562 rsv = (ext4_r_blocks_count(sbi->s_es) >> sbi->s_cluster_bits) +
563 resv_clusters;
564
565 if (free_clusters - (nclusters + rsv + dirty_clusters) <
566 EXT4_FREECLUSTERS_WATERMARK) {
567 free_clusters = percpu_counter_sum_positive(fcc);
568 dirty_clusters = percpu_counter_sum_positive(dcc);
569 }
570 /* Check whether we have space after accounting for current
571 * dirty clusters & root reserved clusters.
572 */
573 if (free_clusters >= (rsv + nclusters + dirty_clusters))
574 return 1;
575
576 /* Hm, nope. Are (enough) root reserved clusters available? */
577 if (uid_eq(sbi->s_resuid, current_fsuid()) ||
578 (!gid_eq(sbi->s_resgid, GLOBAL_ROOT_GID) && in_group_p(sbi->s_resgid)) ||
579 capable(CAP_SYS_RESOURCE) ||
580 (flags & EXT4_MB_USE_ROOT_BLOCKS)) {
581
582 if (free_clusters >= (nclusters + dirty_clusters +
583 resv_clusters))
584 return 1;
585 }
586 /* No free blocks. Let's see if we can dip into reserved pool */
587 if (flags & EXT4_MB_USE_RESERVED) {
588 if (free_clusters >= (nclusters + dirty_clusters))
589 return 1;
590 }
591
592 return 0;
593}
594
595int ext4_claim_free_clusters(struct ext4_sb_info *sbi,
596 s64 nclusters, unsigned int flags)
597{
598 if (ext4_has_free_clusters(sbi, nclusters, flags)) {
599 percpu_counter_add(&sbi->s_dirtyclusters_counter, nclusters);
600 return 0;
601 } else
602 return -ENOSPC;
603}
604
605/**
606 * ext4_should_retry_alloc() - check if a block allocation should be retried
607 * @sb: super block
608 * @retries: number of attemps has been made
609 *
610 * ext4_should_retry_alloc() is called when ENOSPC is returned, and if
611 * it is profitable to retry the operation, this function will wait
612 * for the current or committing transaction to complete, and then
613 * return TRUE. We will only retry once.
614 */
615int ext4_should_retry_alloc(struct super_block *sb, int *retries)
616{
617 if (!ext4_has_free_clusters(EXT4_SB(sb), 1, 0) ||
618 (*retries)++ > 1 ||
619 !EXT4_SB(sb)->s_journal)
620 return 0;
621
622 smp_mb();
623 if (EXT4_SB(sb)->s_mb_free_pending == 0)
624 return 0;
625
626 jbd_debug(1, "%s: retrying operation after ENOSPC\n", sb->s_id);
627 jbd2_journal_force_commit_nested(EXT4_SB(sb)->s_journal);
628 return 1;
629}
630
631/*
632 * ext4_new_meta_blocks() -- allocate block for meta data (indexing) blocks
633 *
634 * @handle: handle to this transaction
635 * @inode: file inode
636 * @goal: given target block(filesystem wide)
637 * @count: pointer to total number of clusters needed
638 * @errp: error code
639 *
640 * Return 1st allocated block number on success, *count stores total account
641 * error stores in errp pointer
642 */
643ext4_fsblk_t ext4_new_meta_blocks(handle_t *handle, struct inode *inode,
644 ext4_fsblk_t goal, unsigned int flags,
645 unsigned long *count, int *errp)
646{
647 struct ext4_allocation_request ar;
648 ext4_fsblk_t ret;
649
650 memset(&ar, 0, sizeof(ar));
651 /* Fill with neighbour allocated blocks */
652 ar.inode = inode;
653 ar.goal = goal;
654 ar.len = count ? *count : 1;
655 ar.flags = flags;
656
657 ret = ext4_mb_new_blocks(handle, &ar, errp);
658 if (count)
659 *count = ar.len;
660 /*
661 * Account for the allocated meta blocks. We will never
662 * fail EDQUOT for metdata, but we do account for it.
663 */
664 if (!(*errp) && (flags & EXT4_MB_DELALLOC_RESERVED)) {
665 dquot_alloc_block_nofail(inode,
666 EXT4_C2B(EXT4_SB(inode->i_sb), ar.len));
667 }
668 return ret;
669}
670
671/**
672 * ext4_count_free_clusters() -- count filesystem free clusters
673 * @sb: superblock
674 *
675 * Adds up the number of free clusters from each block group.
676 */
677ext4_fsblk_t ext4_count_free_clusters(struct super_block *sb)
678{
679 ext4_fsblk_t desc_count;
680 struct ext4_group_desc *gdp;
681 ext4_group_t i;
682 ext4_group_t ngroups = ext4_get_groups_count(sb);
683 struct ext4_group_info *grp;
684#ifdef EXT4FS_DEBUG
685 struct ext4_super_block *es;
686 ext4_fsblk_t bitmap_count;
687 unsigned int x;
688 struct buffer_head *bitmap_bh = NULL;
689
690 es = EXT4_SB(sb)->s_es;
691 desc_count = 0;
692 bitmap_count = 0;
693 gdp = NULL;
694
695 for (i = 0; i < ngroups; i++) {
696 gdp = ext4_get_group_desc(sb, i, NULL);
697 if (!gdp)
698 continue;
699 grp = NULL;
700 if (EXT4_SB(sb)->s_group_info)
701 grp = ext4_get_group_info(sb, i);
702 if (!grp || !EXT4_MB_GRP_BBITMAP_CORRUPT(grp))
703 desc_count += ext4_free_group_clusters(sb, gdp);
704 brelse(bitmap_bh);
705 bitmap_bh = ext4_read_block_bitmap(sb, i);
706 if (IS_ERR(bitmap_bh)) {
707 bitmap_bh = NULL;
708 continue;
709 }
710
711 x = ext4_count_free(bitmap_bh->b_data,
712 EXT4_CLUSTERS_PER_GROUP(sb) / 8);
713 printk(KERN_DEBUG "group %u: stored = %d, counted = %u\n",
714 i, ext4_free_group_clusters(sb, gdp), x);
715 bitmap_count += x;
716 }
717 brelse(bitmap_bh);
718 printk(KERN_DEBUG "ext4_count_free_clusters: stored = %llu"
719 ", computed = %llu, %llu\n",
720 EXT4_NUM_B2C(EXT4_SB(sb), ext4_free_blocks_count(es)),
721 desc_count, bitmap_count);
722 return bitmap_count;
723#else
724 desc_count = 0;
725 for (i = 0; i < ngroups; i++) {
726 gdp = ext4_get_group_desc(sb, i, NULL);
727 if (!gdp)
728 continue;
729 grp = NULL;
730 if (EXT4_SB(sb)->s_group_info)
731 grp = ext4_get_group_info(sb, i);
732 if (!grp || !EXT4_MB_GRP_BBITMAP_CORRUPT(grp))
733 desc_count += ext4_free_group_clusters(sb, gdp);
734 }
735
736 return desc_count;
737#endif
738}
739
740static inline int test_root(ext4_group_t a, int b)
741{
742 while (1) {
743 if (a < b)
744 return 0;
745 if (a == b)
746 return 1;
747 if ((a % b) != 0)
748 return 0;
749 a = a / b;
750 }
751}
752
753/**
754 * ext4_bg_has_super - number of blocks used by the superblock in group
755 * @sb: superblock for filesystem
756 * @group: group number to check
757 *
758 * Return the number of blocks used by the superblock (primary or backup)
759 * in this group. Currently this will be only 0 or 1.
760 */
761int ext4_bg_has_super(struct super_block *sb, ext4_group_t group)
762{
763 struct ext4_super_block *es = EXT4_SB(sb)->s_es;
764
765 if (group == 0)
766 return 1;
767 if (ext4_has_feature_sparse_super2(sb)) {
768 if (group == le32_to_cpu(es->s_backup_bgs[0]) ||
769 group == le32_to_cpu(es->s_backup_bgs[1]))
770 return 1;
771 return 0;
772 }
773 if ((group <= 1) || !ext4_has_feature_sparse_super(sb))
774 return 1;
775 if (!(group & 1))
776 return 0;
777 if (test_root(group, 3) || (test_root(group, 5)) ||
778 test_root(group, 7))
779 return 1;
780
781 return 0;
782}
783
784static unsigned long ext4_bg_num_gdb_meta(struct super_block *sb,
785 ext4_group_t group)
786{
787 unsigned long metagroup = group / EXT4_DESC_PER_BLOCK(sb);
788 ext4_group_t first = metagroup * EXT4_DESC_PER_BLOCK(sb);
789 ext4_group_t last = first + EXT4_DESC_PER_BLOCK(sb) - 1;
790
791 if (group == first || group == first + 1 || group == last)
792 return 1;
793 return 0;
794}
795
796static unsigned long ext4_bg_num_gdb_nometa(struct super_block *sb,
797 ext4_group_t group)
798{
799 if (!ext4_bg_has_super(sb, group))
800 return 0;
801
802 if (ext4_has_feature_meta_bg(sb))
803 return le32_to_cpu(EXT4_SB(sb)->s_es->s_first_meta_bg);
804 else
805 return EXT4_SB(sb)->s_gdb_count;
806}
807
808/**
809 * ext4_bg_num_gdb - number of blocks used by the group table in group
810 * @sb: superblock for filesystem
811 * @group: group number to check
812 *
813 * Return the number of blocks used by the group descriptor table
814 * (primary or backup) in this group. In the future there may be a
815 * different number of descriptor blocks in each group.
816 */
817unsigned long ext4_bg_num_gdb(struct super_block *sb, ext4_group_t group)
818{
819 unsigned long first_meta_bg =
820 le32_to_cpu(EXT4_SB(sb)->s_es->s_first_meta_bg);
821 unsigned long metagroup = group / EXT4_DESC_PER_BLOCK(sb);
822
823 if (!ext4_has_feature_meta_bg(sb) || metagroup < first_meta_bg)
824 return ext4_bg_num_gdb_nometa(sb, group);
825
826 return ext4_bg_num_gdb_meta(sb,group);
827
828}
829
830/*
831 * This function returns the number of file system metadata clusters at
832 * the beginning of a block group, including the reserved gdt blocks.
833 */
834static unsigned ext4_num_base_meta_clusters(struct super_block *sb,
835 ext4_group_t block_group)
836{
837 struct ext4_sb_info *sbi = EXT4_SB(sb);
838 unsigned num;
839
840 /* Check for superblock and gdt backups in this group */
841 num = ext4_bg_has_super(sb, block_group);
842
843 if (!ext4_has_feature_meta_bg(sb) ||
844 block_group < le32_to_cpu(sbi->s_es->s_first_meta_bg) *
845 sbi->s_desc_per_block) {
846 if (num) {
847 num += ext4_bg_num_gdb(sb, block_group);
848 num += le16_to_cpu(sbi->s_es->s_reserved_gdt_blocks);
849 }
850 } else { /* For META_BG_BLOCK_GROUPS */
851 num += ext4_bg_num_gdb(sb, block_group);
852 }
853 return EXT4_NUM_B2C(sbi, num);
854}
855/**
856 * ext4_inode_to_goal_block - return a hint for block allocation
857 * @inode: inode for block allocation
858 *
859 * Return the ideal location to start allocating blocks for a
860 * newly created inode.
861 */
862ext4_fsblk_t ext4_inode_to_goal_block(struct inode *inode)
863{
864 struct ext4_inode_info *ei = EXT4_I(inode);
865 ext4_group_t block_group;
866 ext4_grpblk_t colour;
867 int flex_size = ext4_flex_bg_size(EXT4_SB(inode->i_sb));
868 ext4_fsblk_t bg_start;
869 ext4_fsblk_t last_block;
870
871 block_group = ei->i_block_group;
872 if (flex_size >= EXT4_FLEX_SIZE_DIR_ALLOC_SCHEME) {
873 /*
874 * If there are at least EXT4_FLEX_SIZE_DIR_ALLOC_SCHEME
875 * block groups per flexgroup, reserve the first block
876 * group for directories and special files. Regular
877 * files will start at the second block group. This
878 * tends to speed up directory access and improves
879 * fsck times.
880 */
881 block_group &= ~(flex_size-1);
882 if (S_ISREG(inode->i_mode))
883 block_group++;
884 }
885 bg_start = ext4_group_first_block_no(inode->i_sb, block_group);
886 last_block = ext4_blocks_count(EXT4_SB(inode->i_sb)->s_es) - 1;
887
888 /*
889 * If we are doing delayed allocation, we don't need take
890 * colour into account.
891 */
892 if (test_opt(inode->i_sb, DELALLOC))
893 return bg_start;
894
895 if (bg_start + EXT4_BLOCKS_PER_GROUP(inode->i_sb) <= last_block)
896 colour = (current->pid % 16) *
897 (EXT4_BLOCKS_PER_GROUP(inode->i_sb) / 16);
898 else
899 colour = (current->pid % 16) * ((last_block - bg_start) / 16);
900 return bg_start + colour;
901}
902