1 // SPDX-License-Identifier: GPL-2.0
3 * linux/fs/ext4/balloc.c
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)
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
15 #include <linux/time.h>
16 #include <linux/capability.h>
18 #include <linux/quotaops.h>
19 #include <linux/buffer_head.h>
21 #include "ext4_jbd2.h"
24 #include <trace/events/ext4.h>
26 static unsigned ext4_num_base_meta_clusters(struct super_block
*sb
,
27 ext4_group_t block_group
);
29 * balloc.c contains the blocks allocation and deallocation routines
33 * Calculate block group number for a given block number
35 ext4_group_t
ext4_get_group_number(struct super_block
*sb
,
40 if (test_opt2(sb
, STD_GROUP_SIZE
))
42 le32_to_cpu(EXT4_SB(sb
)->s_es
->s_first_data_block
)) >>
43 (EXT4_BLOCK_SIZE_BITS(sb
) + EXT4_CLUSTER_BITS(sb
) + 3);
45 ext4_get_group_no_and_offset(sb
, block
, &group
, NULL
);
50 * Calculate the block group number and offset into the block/cluster
51 * allocation bitmap, given a block number
53 void ext4_get_group_no_and_offset(struct super_block
*sb
, ext4_fsblk_t blocknr
,
54 ext4_group_t
*blockgrpp
, ext4_grpblk_t
*offsetp
)
56 struct ext4_super_block
*es
= EXT4_SB(sb
)->s_es
;
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
;
70 * Check whether the 'block' lives within the 'block_group'. Returns 1 if so
73 static inline int ext4_block_in_group(struct super_block
*sb
,
75 ext4_group_t block_group
)
77 ext4_group_t actual_group
;
79 actual_group
= ext4_get_group_number(sb
, block
);
80 return (actual_group
== block_group
) ? 1 : 0;
83 /* Return the number of clusters used for file system metadata; this
84 * represents the overhead needed by the file system.
86 static unsigned ext4_num_overhead_clusters(struct super_block
*sb
,
87 ext4_group_t block_group
,
88 struct ext4_group_desc
*gdp
)
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
);
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
);
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.
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
)
118 else if (block_cluster
== num_clusters
) {
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
)
129 else if (inode_cluster
== num_clusters
) {
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
))
142 if (c
== num_clusters
) {
151 if (block_cluster
!= -1)
153 if (inode_cluster
!= -1)
159 static unsigned int num_clusters_in_group(struct super_block
*sb
,
160 ext4_group_t block_group
)
164 if (block_group
== ext4_get_groups_count(sb
) - 1) {
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
171 blocks
= ext4_blocks_count(EXT4_SB(sb
)->s_es
) -
172 ext4_group_first_block_no(sb
, block_group
);
174 blocks
= EXT4_BLOCKS_PER_GROUP(sb
);
175 return EXT4_NUM_B2C(EXT4_SB(sb
), blocks
);
178 /* Initializes an uninitialized block bitmap */
179 static 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
)
184 unsigned int bit
, bit_max
;
185 struct ext4_sb_info
*sbi
= EXT4_SB(sb
);
186 ext4_fsblk_t start
, tmp
;
188 ASSERT(buffer_locked(bh
));
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
);
198 memset(bh
->b_data
, 0, sb
->s_blocksize
);
200 bit_max
= ext4_num_base_meta_clusters(sb
, block_group
);
201 if ((bit_max
>> 3) >= bh
->b_size
)
202 return -EFSCORRUPTED
;
204 for (bit
= 0; bit
< bit_max
; bit
++)
205 ext4_set_bit(bit
, bh
->b_data
);
207 start
= ext4_group_first_block_no(sb
, block_group
);
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
);
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
);
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
);
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
230 ext4_mark_bitmap_end(num_clusters_in_group(sb
, block_group
),
231 sb
->s_blocksize
* 8, bh
->b_data
);
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
238 unsigned ext4_free_clusters_after_init(struct super_block
*sb
,
239 ext4_group_t block_group
,
240 struct ext4_group_desc
*gdp
)
242 return num_clusters_in_group(sb
, block_group
) -
243 ext4_num_overhead_clusters(sb
, block_group
, gdp
);
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.
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).
258 * ext4_get_group_desc() -- load group descriptor from disk
260 * @block_group: given block group
261 * @bh: pointer to the buffer head to store the block
264 struct ext4_group_desc
* ext4_get_group_desc(struct super_block
*sb
,
265 ext4_group_t block_group
,
266 struct buffer_head
**bh
)
268 unsigned int group_desc
;
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
;
275 if (block_group
>= ngroups
) {
276 ext4_error(sb
, "block_group >= groups_count - block_group = %u,"
277 " groups_count = %u", block_group
, ngroups
);
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
);
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.
292 ext4_error(sb
, "Group descriptor not loaded - "
293 "block_group = %u, group_desc = %u, desc = %u",
294 block_group
, group_desc
, offset
);
298 desc
= (struct ext4_group_desc
*)(
299 (__u8
*)bh_p
->b_data
+
300 offset
* EXT4_DESC_SIZE(sb
));
307 * Return the block number which was discovered to be invalid, or 0 if
308 * the block bitmap is valid.
310 static 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
)
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
);
320 ext4_fsblk_t group_first_block
;
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.
331 group_first_block
= ext4_group_first_block_no(sb
, block_group
);
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 */
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 */
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
)
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
));
359 EXT4_B2C(sbi
, offset
+ sbi
->s_itb_per_group
))
360 /* bad bitmap for inode tables */
365 static 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
)
371 struct ext4_group_info
*grp
;
373 if (EXT4_SB(sb
)->s_mount_state
& EXT4_FC_REPLAY
)
376 grp
= ext4_get_group_info(sb
, block_group
);
378 if (buffer_verified(bh
))
380 if (EXT4_MB_GRP_BBITMAP_CORRUPT(grp
))
381 return -EFSCORRUPTED
;
383 ext4_lock_group(sb
, block_group
);
384 if (buffer_verified(bh
))
386 if (unlikely(!ext4_block_bitmap_csum_verify(sb
, block_group
,
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
);
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",
400 ext4_mark_group_bitmap_corrupted(sb
, block_group
,
401 EXT4_GROUP_INFO_BBITMAP_CORRUPT
);
402 return -EFSCORRUPTED
;
404 set_buffer_verified(bh
);
406 ext4_unlock_group(sb
, block_group
);
411 * ext4_read_block_bitmap_nowait()
413 * @block_group: given block group
414 * @ignore_locked: ignore locked buffers
416 * Read the bitmap for a given block_group,and validate the
417 * bits for block/inode/inode tables are set in the bitmaps
419 * Return buffer_head on success or an ERR_PTR in case of failure.
422 ext4_read_block_bitmap_nowait(struct super_block
*sb
, ext4_group_t block_group
,
425 struct ext4_group_desc
*desc
;
426 struct ext4_sb_info
*sbi
= EXT4_SB(sb
);
427 struct buffer_head
*bh
;
428 ext4_fsblk_t bitmap_blk
;
431 desc
= ext4_get_group_desc(sb
, block_group
, NULL
);
433 return ERR_PTR(-EFSCORRUPTED
);
434 bitmap_blk
= ext4_block_bitmap(sb
, desc
);
435 if ((bitmap_blk
<= le32_to_cpu(sbi
->s_es
->s_first_data_block
)) ||
436 (bitmap_blk
>= ext4_blocks_count(sbi
->s_es
))) {
437 ext4_error(sb
, "Invalid block bitmap block %llu in "
438 "block_group %u", bitmap_blk
, block_group
);
439 ext4_mark_group_bitmap_corrupted(sb
, block_group
,
440 EXT4_GROUP_INFO_BBITMAP_CORRUPT
);
441 return ERR_PTR(-EFSCORRUPTED
);
443 bh
= sb_getblk(sb
, bitmap_blk
);
445 ext4_warning(sb
, "Cannot get buffer for block bitmap - "
446 "block_group = %u, block_bitmap = %llu",
447 block_group
, bitmap_blk
);
448 return ERR_PTR(-ENOMEM
);
451 if (ignore_locked
&& buffer_locked(bh
)) {
452 /* buffer under IO already, return if called for prefetching */
457 if (bitmap_uptodate(bh
))
461 if (bitmap_uptodate(bh
)) {
465 ext4_lock_group(sb
, block_group
);
466 if (ext4_has_group_desc_csum(sb
) &&
467 (desc
->bg_flags
& cpu_to_le16(EXT4_BG_BLOCK_UNINIT
))) {
468 if (block_group
== 0) {
469 ext4_unlock_group(sb
, block_group
);
471 ext4_error(sb
, "Block bitmap for bg 0 marked "
476 err
= ext4_init_block_bitmap(sb
, bh
, block_group
, desc
);
477 set_bitmap_uptodate(bh
);
478 set_buffer_uptodate(bh
);
479 set_buffer_verified(bh
);
480 ext4_unlock_group(sb
, block_group
);
483 ext4_error(sb
, "Failed to init block bitmap for group "
484 "%u: %d", block_group
, err
);
489 ext4_unlock_group(sb
, block_group
);
490 if (buffer_uptodate(bh
)) {
492 * if not uninit if bh is uptodate,
493 * bitmap is also uptodate
495 set_bitmap_uptodate(bh
);
500 * submit the buffer_head for reading
503 trace_ext4_read_block_bitmap_load(sb
, block_group
, ignore_locked
);
504 ext4_read_bh_nowait(bh
, REQ_META
| REQ_PRIO
|
505 (ignore_locked
? REQ_RAHEAD
: 0),
506 ext4_end_bitmap_read
);
509 err
= ext4_validate_block_bitmap(sb
, desc
, block_group
, bh
);
518 /* Returns 0 on success, -errno on error */
519 int ext4_wait_block_bitmap(struct super_block
*sb
, ext4_group_t block_group
,
520 struct buffer_head
*bh
)
522 struct ext4_group_desc
*desc
;
526 desc
= ext4_get_group_desc(sb
, block_group
, NULL
);
528 return -EFSCORRUPTED
;
530 ext4_simulate_fail_bh(sb
, bh
, EXT4_SIM_BBITMAP_EIO
);
531 if (!buffer_uptodate(bh
)) {
532 ext4_error_err(sb
, EIO
, "Cannot read block bitmap - "
533 "block_group = %u, block_bitmap = %llu",
534 block_group
, (unsigned long long) bh
->b_blocknr
);
535 ext4_mark_group_bitmap_corrupted(sb
, block_group
,
536 EXT4_GROUP_INFO_BBITMAP_CORRUPT
);
539 clear_buffer_new(bh
);
540 /* Panic or remount fs read-only if block bitmap is invalid */
541 return ext4_validate_block_bitmap(sb
, desc
, block_group
, bh
);
545 ext4_read_block_bitmap(struct super_block
*sb
, ext4_group_t block_group
)
547 struct buffer_head
*bh
;
550 bh
= ext4_read_block_bitmap_nowait(sb
, block_group
, false);
553 err
= ext4_wait_block_bitmap(sb
, block_group
, bh
);
562 * ext4_has_free_clusters()
563 * @sbi: in-core super block structure.
564 * @nclusters: number of needed blocks
565 * @flags: flags from ext4_mb_new_blocks()
567 * Check if filesystem has nclusters free & available for allocation.
568 * On success return 1, return 0 on failure.
570 static int ext4_has_free_clusters(struct ext4_sb_info
*sbi
,
571 s64 nclusters
, unsigned int flags
)
573 s64 free_clusters
, dirty_clusters
, rsv
, resv_clusters
;
574 struct percpu_counter
*fcc
= &sbi
->s_freeclusters_counter
;
575 struct percpu_counter
*dcc
= &sbi
->s_dirtyclusters_counter
;
577 free_clusters
= percpu_counter_read_positive(fcc
);
578 dirty_clusters
= percpu_counter_read_positive(dcc
);
579 resv_clusters
= atomic64_read(&sbi
->s_resv_clusters
);
582 * r_blocks_count should always be multiple of the cluster ratio so
583 * we are safe to do a plane bit shift only.
585 rsv
= (ext4_r_blocks_count(sbi
->s_es
) >> sbi
->s_cluster_bits
) +
588 if (free_clusters
- (nclusters
+ rsv
+ dirty_clusters
) <
589 EXT4_FREECLUSTERS_WATERMARK
) {
590 free_clusters
= percpu_counter_sum_positive(fcc
);
591 dirty_clusters
= percpu_counter_sum_positive(dcc
);
593 /* Check whether we have space after accounting for current
594 * dirty clusters & root reserved clusters.
596 if (free_clusters
>= (rsv
+ nclusters
+ dirty_clusters
))
599 /* Hm, nope. Are (enough) root reserved clusters available? */
600 if (uid_eq(sbi
->s_resuid
, current_fsuid()) ||
601 (!gid_eq(sbi
->s_resgid
, GLOBAL_ROOT_GID
) && in_group_p(sbi
->s_resgid
)) ||
602 capable(CAP_SYS_RESOURCE
) ||
603 (flags
& EXT4_MB_USE_ROOT_BLOCKS
)) {
605 if (free_clusters
>= (nclusters
+ dirty_clusters
+
609 /* No free blocks. Let's see if we can dip into reserved pool */
610 if (flags
& EXT4_MB_USE_RESERVED
) {
611 if (free_clusters
>= (nclusters
+ dirty_clusters
))
618 int ext4_claim_free_clusters(struct ext4_sb_info
*sbi
,
619 s64 nclusters
, unsigned int flags
)
621 if (ext4_has_free_clusters(sbi
, nclusters
, flags
)) {
622 percpu_counter_add(&sbi
->s_dirtyclusters_counter
, nclusters
);
629 * ext4_should_retry_alloc() - check if a block allocation should be retried
631 * @retries: number of retry attempts made so far
633 * ext4_should_retry_alloc() is called when ENOSPC is returned while
634 * attempting to allocate blocks. If there's an indication that a pending
635 * journal transaction might free some space and allow another attempt to
636 * succeed, this function will wait for the current or committing transaction
637 * to complete and then return TRUE.
639 int ext4_should_retry_alloc(struct super_block
*sb
, int *retries
)
641 struct ext4_sb_info
*sbi
= EXT4_SB(sb
);
646 if (++(*retries
) > 3) {
647 percpu_counter_inc(&sbi
->s_sra_exceeded_retry_limit
);
652 * if there's no indication that blocks are about to be freed it's
653 * possible we just missed a transaction commit that did so
656 if (sbi
->s_mb_free_pending
== 0) {
657 if (test_opt(sb
, DISCARD
)) {
658 atomic_inc(&sbi
->s_retry_alloc_pending
);
659 flush_work(&sbi
->s_discard_work
);
660 atomic_dec(&sbi
->s_retry_alloc_pending
);
662 return ext4_has_free_clusters(sbi
, 1, 0);
666 * it's possible we've just missed a transaction commit here,
667 * so ignore the returned status
669 ext4_debug("%s: retrying operation after ENOSPC\n", sb
->s_id
);
670 (void) jbd2_journal_force_commit_nested(sbi
->s_journal
);
675 * ext4_new_meta_blocks() -- allocate block for meta data (indexing) blocks
677 * @handle: handle to this transaction
679 * @goal: given target block(filesystem wide)
680 * @count: pointer to total number of clusters needed
683 * Return 1st allocated block number on success, *count stores total account
684 * error stores in errp pointer
686 ext4_fsblk_t
ext4_new_meta_blocks(handle_t
*handle
, struct inode
*inode
,
687 ext4_fsblk_t goal
, unsigned int flags
,
688 unsigned long *count
, int *errp
)
690 struct ext4_allocation_request ar
;
693 memset(&ar
, 0, sizeof(ar
));
694 /* Fill with neighbour allocated blocks */
697 ar
.len
= count
? *count
: 1;
700 ret
= ext4_mb_new_blocks(handle
, &ar
, errp
);
704 * Account for the allocated meta blocks. We will never
705 * fail EDQUOT for metdata, but we do account for it.
707 if (!(*errp
) && (flags
& EXT4_MB_DELALLOC_RESERVED
)) {
708 dquot_alloc_block_nofail(inode
,
709 EXT4_C2B(EXT4_SB(inode
->i_sb
), ar
.len
));
715 * ext4_count_free_clusters() -- count filesystem free clusters
718 * Adds up the number of free clusters from each block group.
720 ext4_fsblk_t
ext4_count_free_clusters(struct super_block
*sb
)
722 ext4_fsblk_t desc_count
;
723 struct ext4_group_desc
*gdp
;
725 ext4_group_t ngroups
= ext4_get_groups_count(sb
);
726 struct ext4_group_info
*grp
;
728 struct ext4_super_block
*es
;
729 ext4_fsblk_t bitmap_count
;
731 struct buffer_head
*bitmap_bh
= NULL
;
733 es
= EXT4_SB(sb
)->s_es
;
738 for (i
= 0; i
< ngroups
; i
++) {
739 gdp
= ext4_get_group_desc(sb
, i
, NULL
);
743 if (EXT4_SB(sb
)->s_group_info
)
744 grp
= ext4_get_group_info(sb
, i
);
745 if (!grp
|| !EXT4_MB_GRP_BBITMAP_CORRUPT(grp
))
746 desc_count
+= ext4_free_group_clusters(sb
, gdp
);
748 bitmap_bh
= ext4_read_block_bitmap(sb
, i
);
749 if (IS_ERR(bitmap_bh
)) {
754 x
= ext4_count_free(bitmap_bh
->b_data
,
755 EXT4_CLUSTERS_PER_GROUP(sb
) / 8);
756 printk(KERN_DEBUG
"group %u: stored = %d, counted = %u\n",
757 i
, ext4_free_group_clusters(sb
, gdp
), x
);
761 printk(KERN_DEBUG
"ext4_count_free_clusters: stored = %llu"
762 ", computed = %llu, %llu\n",
763 EXT4_NUM_B2C(EXT4_SB(sb
), ext4_free_blocks_count(es
)),
764 desc_count
, bitmap_count
);
768 for (i
= 0; i
< ngroups
; i
++) {
769 gdp
= ext4_get_group_desc(sb
, i
, NULL
);
773 if (EXT4_SB(sb
)->s_group_info
)
774 grp
= ext4_get_group_info(sb
, i
);
775 if (!grp
|| !EXT4_MB_GRP_BBITMAP_CORRUPT(grp
))
776 desc_count
+= ext4_free_group_clusters(sb
, gdp
);
783 static inline int test_root(ext4_group_t a
, int b
)
797 * ext4_bg_has_super - number of blocks used by the superblock in group
798 * @sb: superblock for filesystem
799 * @group: group number to check
801 * Return the number of blocks used by the superblock (primary or backup)
802 * in this group. Currently this will be only 0 or 1.
804 int ext4_bg_has_super(struct super_block
*sb
, ext4_group_t group
)
806 struct ext4_super_block
*es
= EXT4_SB(sb
)->s_es
;
810 if (ext4_has_feature_sparse_super2(sb
)) {
811 if (group
== le32_to_cpu(es
->s_backup_bgs
[0]) ||
812 group
== le32_to_cpu(es
->s_backup_bgs
[1]))
816 if ((group
<= 1) || !ext4_has_feature_sparse_super(sb
))
820 if (test_root(group
, 3) || (test_root(group
, 5)) ||
827 static unsigned long ext4_bg_num_gdb_meta(struct super_block
*sb
,
830 unsigned long metagroup
= group
/ EXT4_DESC_PER_BLOCK(sb
);
831 ext4_group_t first
= metagroup
* EXT4_DESC_PER_BLOCK(sb
);
832 ext4_group_t last
= first
+ EXT4_DESC_PER_BLOCK(sb
) - 1;
834 if (group
== first
|| group
== first
+ 1 || group
== last
)
839 static unsigned long ext4_bg_num_gdb_nometa(struct super_block
*sb
,
842 if (!ext4_bg_has_super(sb
, group
))
845 if (ext4_has_feature_meta_bg(sb
))
846 return le32_to_cpu(EXT4_SB(sb
)->s_es
->s_first_meta_bg
);
848 return EXT4_SB(sb
)->s_gdb_count
;
852 * ext4_bg_num_gdb - number of blocks used by the group table in group
853 * @sb: superblock for filesystem
854 * @group: group number to check
856 * Return the number of blocks used by the group descriptor table
857 * (primary or backup) in this group. In the future there may be a
858 * different number of descriptor blocks in each group.
860 unsigned long ext4_bg_num_gdb(struct super_block
*sb
, ext4_group_t group
)
862 unsigned long first_meta_bg
=
863 le32_to_cpu(EXT4_SB(sb
)->s_es
->s_first_meta_bg
);
864 unsigned long metagroup
= group
/ EXT4_DESC_PER_BLOCK(sb
);
866 if (!ext4_has_feature_meta_bg(sb
) || metagroup
< first_meta_bg
)
867 return ext4_bg_num_gdb_nometa(sb
, group
);
869 return ext4_bg_num_gdb_meta(sb
,group
);
874 * This function returns the number of file system metadata clusters at
875 * the beginning of a block group, including the reserved gdt blocks.
877 static unsigned ext4_num_base_meta_clusters(struct super_block
*sb
,
878 ext4_group_t block_group
)
880 struct ext4_sb_info
*sbi
= EXT4_SB(sb
);
883 /* Check for superblock and gdt backups in this group */
884 num
= ext4_bg_has_super(sb
, block_group
);
886 if (!ext4_has_feature_meta_bg(sb
) ||
887 block_group
< le32_to_cpu(sbi
->s_es
->s_first_meta_bg
) *
888 sbi
->s_desc_per_block
) {
890 num
+= ext4_bg_num_gdb(sb
, block_group
);
891 num
+= le16_to_cpu(sbi
->s_es
->s_reserved_gdt_blocks
);
893 } else { /* For META_BG_BLOCK_GROUPS */
894 num
+= ext4_bg_num_gdb(sb
, block_group
);
896 return EXT4_NUM_B2C(sbi
, num
);
899 * ext4_inode_to_goal_block - return a hint for block allocation
900 * @inode: inode for block allocation
902 * Return the ideal location to start allocating blocks for a
903 * newly created inode.
905 ext4_fsblk_t
ext4_inode_to_goal_block(struct inode
*inode
)
907 struct ext4_inode_info
*ei
= EXT4_I(inode
);
908 ext4_group_t block_group
;
909 ext4_grpblk_t colour
;
910 int flex_size
= ext4_flex_bg_size(EXT4_SB(inode
->i_sb
));
911 ext4_fsblk_t bg_start
;
912 ext4_fsblk_t last_block
;
914 block_group
= ei
->i_block_group
;
915 if (flex_size
>= EXT4_FLEX_SIZE_DIR_ALLOC_SCHEME
) {
917 * If there are at least EXT4_FLEX_SIZE_DIR_ALLOC_SCHEME
918 * block groups per flexgroup, reserve the first block
919 * group for directories and special files. Regular
920 * files will start at the second block group. This
921 * tends to speed up directory access and improves
924 block_group
&= ~(flex_size
-1);
925 if (S_ISREG(inode
->i_mode
))
928 bg_start
= ext4_group_first_block_no(inode
->i_sb
, block_group
);
929 last_block
= ext4_blocks_count(EXT4_SB(inode
->i_sb
)->s_es
) - 1;
932 * If we are doing delayed allocation, we don't need take
933 * colour into account.
935 if (test_opt(inode
->i_sb
, DELALLOC
))
938 if (bg_start
+ EXT4_BLOCKS_PER_GROUP(inode
->i_sb
) <= last_block
)
939 colour
= (task_pid_nr(current
) % 16) *
940 (EXT4_BLOCKS_PER_GROUP(inode
->i_sb
) / 16);
942 colour
= (task_pid_nr(current
) % 16) *
943 ((last_block
- bg_start
) / 16);
944 return bg_start
+ colour
;