2 * linux/fs/ext4/balloc.c
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)
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
14 #include <linux/time.h>
15 #include <linux/capability.h>
17 #include <linux/jbd2.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 the block group number and offset into the block/cluster
34 * allocation bitmap, given a block number
36 void ext4_get_group_no_and_offset(struct super_block
*sb
, ext4_fsblk_t blocknr
,
37 ext4_group_t
*blockgrpp
, ext4_grpblk_t
*offsetp
)
39 struct ext4_super_block
*es
= EXT4_SB(sb
)->s_es
;
42 blocknr
= blocknr
- le32_to_cpu(es
->s_first_data_block
);
43 offset
= do_div(blocknr
, EXT4_BLOCKS_PER_GROUP(sb
)) >>
44 EXT4_SB(sb
)->s_cluster_bits
;
52 static int ext4_block_in_group(struct super_block
*sb
, ext4_fsblk_t block
,
53 ext4_group_t block_group
)
55 ext4_group_t actual_group
;
56 ext4_get_group_no_and_offset(sb
, block
, &actual_group
, NULL
);
57 if (actual_group
== block_group
)
62 /* Return the number of clusters used for file system metadata; this
63 * represents the overhead needed by the file system.
65 unsigned ext4_num_overhead_clusters(struct super_block
*sb
,
66 ext4_group_t block_group
,
67 struct ext4_group_desc
*gdp
)
69 unsigned num_clusters
;
70 int block_cluster
= -1, inode_cluster
= -1, itbl_cluster
= -1, i
, c
;
71 ext4_fsblk_t start
= ext4_group_first_block_no(sb
, block_group
);
72 ext4_fsblk_t itbl_blk
;
73 struct ext4_sb_info
*sbi
= EXT4_SB(sb
);
75 /* This is the number of clusters used by the superblock,
76 * block group descriptors, and reserved block group
77 * descriptor blocks */
78 num_clusters
= ext4_num_base_meta_clusters(sb
, block_group
);
81 * For the allocation bitmaps and inode table, we first need
82 * to check to see if the block is in the block group. If it
83 * is, then check to see if the cluster is already accounted
84 * for in the clusters used for the base metadata cluster, or
85 * if we can increment the base metadata cluster to include
86 * that block. Otherwise, we will have to track the cluster
87 * used for the allocation bitmap or inode table explicitly.
88 * Normally all of these blocks are contiguous, so the special
89 * case handling shouldn't be necessary except for *very*
90 * unusual file system layouts.
92 if (ext4_block_in_group(sb
, ext4_block_bitmap(sb
, gdp
), block_group
)) {
93 block_cluster
= EXT4_B2C(sbi
,
94 ext4_block_bitmap(sb
, gdp
) - start
);
95 if (block_cluster
< num_clusters
)
97 else if (block_cluster
== num_clusters
) {
103 if (ext4_block_in_group(sb
, ext4_inode_bitmap(sb
, gdp
), block_group
)) {
104 inode_cluster
= EXT4_B2C(sbi
,
105 ext4_inode_bitmap(sb
, gdp
) - start
);
106 if (inode_cluster
< num_clusters
)
108 else if (inode_cluster
== num_clusters
) {
114 itbl_blk
= ext4_inode_table(sb
, gdp
);
115 for (i
= 0; i
< sbi
->s_itb_per_group
; i
++) {
116 if (ext4_block_in_group(sb
, itbl_blk
+ i
, block_group
)) {
117 c
= EXT4_B2C(sbi
, itbl_blk
+ i
- start
);
118 if ((c
< num_clusters
) || (c
== inode_cluster
) ||
119 (c
== block_cluster
) || (c
== itbl_cluster
))
121 if (c
== num_clusters
) {
130 if (block_cluster
!= -1)
132 if (inode_cluster
!= -1)
138 static unsigned int num_clusters_in_group(struct super_block
*sb
,
139 ext4_group_t block_group
)
143 if (block_group
== ext4_get_groups_count(sb
) - 1) {
145 * Even though mke2fs always initializes the first and
146 * last group, just in case some other tool was used,
147 * we need to make sure we calculate the right free
150 blocks
= ext4_blocks_count(EXT4_SB(sb
)->s_es
) -
151 ext4_group_first_block_no(sb
, block_group
);
153 blocks
= EXT4_BLOCKS_PER_GROUP(sb
);
154 return EXT4_NUM_B2C(EXT4_SB(sb
), blocks
);
157 /* Initializes an uninitialized block bitmap */
158 void ext4_init_block_bitmap(struct super_block
*sb
, struct buffer_head
*bh
,
159 ext4_group_t block_group
,
160 struct ext4_group_desc
*gdp
)
162 unsigned int bit
, bit_max
;
163 struct ext4_sb_info
*sbi
= EXT4_SB(sb
);
164 ext4_fsblk_t start
, tmp
;
167 J_ASSERT_BH(bh
, buffer_locked(bh
));
169 /* If checksum is bad mark all blocks used to prevent allocation
170 * essentially implementing a per-group read-only flag. */
171 if (!ext4_group_desc_csum_verify(sb
, block_group
, gdp
)) {
172 ext4_error(sb
, "Checksum bad for group %u", block_group
);
173 ext4_free_group_clusters_set(sb
, gdp
, 0);
174 ext4_free_inodes_set(sb
, gdp
, 0);
175 ext4_itable_unused_set(sb
, gdp
, 0);
176 memset(bh
->b_data
, 0xff, sb
->s_blocksize
);
177 ext4_block_bitmap_csum_set(sb
, block_group
, gdp
, bh
,
178 EXT4_BLOCKS_PER_GROUP(sb
) / 8);
181 memset(bh
->b_data
, 0, sb
->s_blocksize
);
183 bit_max
= ext4_num_base_meta_clusters(sb
, block_group
);
184 for (bit
= 0; bit
< bit_max
; bit
++)
185 ext4_set_bit(bit
, bh
->b_data
);
187 start
= ext4_group_first_block_no(sb
, block_group
);
189 if (EXT4_HAS_INCOMPAT_FEATURE(sb
, EXT4_FEATURE_INCOMPAT_FLEX_BG
))
192 /* Set bits for block and inode bitmaps, and inode table */
193 tmp
= ext4_block_bitmap(sb
, gdp
);
194 if (!flex_bg
|| ext4_block_in_group(sb
, tmp
, block_group
))
195 ext4_set_bit(EXT4_B2C(sbi
, tmp
- start
), bh
->b_data
);
197 tmp
= ext4_inode_bitmap(sb
, gdp
);
198 if (!flex_bg
|| ext4_block_in_group(sb
, tmp
, block_group
))
199 ext4_set_bit(EXT4_B2C(sbi
, tmp
- start
), bh
->b_data
);
201 tmp
= ext4_inode_table(sb
, gdp
);
202 for (; tmp
< ext4_inode_table(sb
, gdp
) +
203 sbi
->s_itb_per_group
; tmp
++) {
204 if (!flex_bg
|| ext4_block_in_group(sb
, tmp
, block_group
))
205 ext4_set_bit(EXT4_B2C(sbi
, tmp
- start
), bh
->b_data
);
209 * Also if the number of blocks within the group is less than
210 * the blocksize * 8 ( which is the size of bitmap ), set rest
211 * of the block bitmap to 1
213 ext4_mark_bitmap_end(num_clusters_in_group(sb
, block_group
),
214 sb
->s_blocksize
* 8, bh
->b_data
);
215 ext4_block_bitmap_csum_set(sb
, block_group
, gdp
, bh
,
216 EXT4_BLOCKS_PER_GROUP(sb
) / 8);
217 ext4_group_desc_csum_set(sb
, block_group
, gdp
);
220 /* Return the number of free blocks in a block group. It is used when
221 * the block bitmap is uninitialized, so we can't just count the bits
223 unsigned ext4_free_clusters_after_init(struct super_block
*sb
,
224 ext4_group_t block_group
,
225 struct ext4_group_desc
*gdp
)
227 return num_clusters_in_group(sb
, block_group
) -
228 ext4_num_overhead_clusters(sb
, block_group
, gdp
);
232 * The free blocks are managed by bitmaps. A file system contains several
233 * blocks groups. Each group contains 1 bitmap block for blocks, 1 bitmap
234 * block for inodes, N blocks for the inode table and data blocks.
236 * The file system contains group descriptors which are located after the
237 * super block. Each descriptor contains the number of the bitmap block and
238 * the free blocks count in the block. The descriptors are loaded in memory
239 * when a file system is mounted (see ext4_fill_super).
243 * ext4_get_group_desc() -- load group descriptor from disk
245 * @block_group: given block group
246 * @bh: pointer to the buffer head to store the block
249 struct ext4_group_desc
* ext4_get_group_desc(struct super_block
*sb
,
250 ext4_group_t block_group
,
251 struct buffer_head
**bh
)
253 unsigned int group_desc
;
255 ext4_group_t ngroups
= ext4_get_groups_count(sb
);
256 struct ext4_group_desc
*desc
;
257 struct ext4_sb_info
*sbi
= EXT4_SB(sb
);
259 if (block_group
>= ngroups
) {
260 ext4_error(sb
, "block_group >= groups_count - block_group = %u,"
261 " groups_count = %u", block_group
, ngroups
);
266 group_desc
= block_group
>> EXT4_DESC_PER_BLOCK_BITS(sb
);
267 offset
= block_group
& (EXT4_DESC_PER_BLOCK(sb
) - 1);
268 if (!sbi
->s_group_desc
[group_desc
]) {
269 ext4_error(sb
, "Group descriptor not loaded - "
270 "block_group = %u, group_desc = %u, desc = %u",
271 block_group
, group_desc
, offset
);
275 desc
= (struct ext4_group_desc
*)(
276 (__u8
*)sbi
->s_group_desc
[group_desc
]->b_data
+
277 offset
* EXT4_DESC_SIZE(sb
));
279 *bh
= sbi
->s_group_desc
[group_desc
];
284 * Return the block number which was discovered to be invalid, or 0 if
285 * the block bitmap is valid.
287 static ext4_fsblk_t
ext4_valid_block_bitmap(struct super_block
*sb
,
288 struct ext4_group_desc
*desc
,
289 unsigned int block_group
,
290 struct buffer_head
*bh
)
292 ext4_grpblk_t offset
;
293 ext4_grpblk_t next_zero_bit
;
295 ext4_fsblk_t group_first_block
;
297 if (EXT4_HAS_INCOMPAT_FEATURE(sb
, EXT4_FEATURE_INCOMPAT_FLEX_BG
)) {
298 /* with FLEX_BG, the inode/block bitmaps and itable
299 * blocks may not be in the group at all
300 * so the bitmap validation will be skipped for those groups
301 * or it has to also read the block group where the bitmaps
302 * are located to verify they are set.
306 group_first_block
= ext4_group_first_block_no(sb
, block_group
);
308 /* check whether block bitmap block number is set */
309 blk
= ext4_block_bitmap(sb
, desc
);
310 offset
= blk
- group_first_block
;
311 if (!ext4_test_bit(offset
, bh
->b_data
))
312 /* bad block bitmap */
315 /* check whether the inode bitmap block number is set */
316 blk
= ext4_inode_bitmap(sb
, desc
);
317 offset
= blk
- group_first_block
;
318 if (!ext4_test_bit(offset
, bh
->b_data
))
319 /* bad block bitmap */
322 /* check whether the inode table block number is set */
323 blk
= ext4_inode_table(sb
, desc
);
324 offset
= blk
- group_first_block
;
325 next_zero_bit
= ext4_find_next_zero_bit(bh
->b_data
,
326 offset
+ EXT4_SB(sb
)->s_itb_per_group
,
328 if (next_zero_bit
< offset
+ EXT4_SB(sb
)->s_itb_per_group
)
329 /* bad bitmap for inode tables */
334 void ext4_validate_block_bitmap(struct super_block
*sb
,
335 struct ext4_group_desc
*desc
,
336 unsigned int block_group
,
337 struct buffer_head
*bh
)
341 if (buffer_verified(bh
))
344 ext4_lock_group(sb
, block_group
);
345 blk
= ext4_valid_block_bitmap(sb
, desc
, block_group
, bh
);
346 if (unlikely(blk
!= 0)) {
347 ext4_unlock_group(sb
, block_group
);
348 ext4_error(sb
, "bg %u: block %llu: invalid block bitmap",
352 if (unlikely(!ext4_block_bitmap_csum_verify(sb
, block_group
,
353 desc
, bh
, EXT4_BLOCKS_PER_GROUP(sb
) / 8))) {
354 ext4_unlock_group(sb
, block_group
);
355 ext4_error(sb
, "bg %u: bad block bitmap checksum", block_group
);
358 set_buffer_verified(bh
);
359 ext4_unlock_group(sb
, block_group
);
363 * ext4_read_block_bitmap()
365 * @block_group: given block group
367 * Read the bitmap for a given block_group,and validate the
368 * bits for block/inode/inode tables are set in the bitmaps
370 * Return buffer_head on success or NULL in case of failure.
373 ext4_read_block_bitmap_nowait(struct super_block
*sb
, ext4_group_t block_group
)
375 struct ext4_group_desc
*desc
;
376 struct buffer_head
*bh
;
377 ext4_fsblk_t bitmap_blk
;
379 desc
= ext4_get_group_desc(sb
, block_group
, NULL
);
382 bitmap_blk
= ext4_block_bitmap(sb
, desc
);
383 bh
= sb_getblk(sb
, bitmap_blk
);
385 ext4_error(sb
, "Cannot get buffer for block bitmap - "
386 "block_group = %u, block_bitmap = %llu",
387 block_group
, bitmap_blk
);
391 if (bitmap_uptodate(bh
))
395 if (bitmap_uptodate(bh
)) {
399 ext4_lock_group(sb
, block_group
);
400 if (desc
->bg_flags
& cpu_to_le16(EXT4_BG_BLOCK_UNINIT
)) {
401 ext4_init_block_bitmap(sb
, bh
, block_group
, desc
);
402 set_bitmap_uptodate(bh
);
403 set_buffer_uptodate(bh
);
404 ext4_unlock_group(sb
, block_group
);
408 ext4_unlock_group(sb
, block_group
);
409 if (buffer_uptodate(bh
)) {
411 * if not uninit if bh is uptodate,
412 * bitmap is also uptodate
414 set_bitmap_uptodate(bh
);
419 * submit the buffer_head for reading
422 trace_ext4_read_block_bitmap_load(sb
, block_group
);
423 bh
->b_end_io
= ext4_end_bitmap_read
;
428 ext4_validate_block_bitmap(sb
, desc
, block_group
, bh
);
432 /* Returns 0 on success, 1 on error */
433 int ext4_wait_block_bitmap(struct super_block
*sb
, ext4_group_t block_group
,
434 struct buffer_head
*bh
)
436 struct ext4_group_desc
*desc
;
440 desc
= ext4_get_group_desc(sb
, block_group
, NULL
);
444 if (!buffer_uptodate(bh
)) {
445 ext4_error(sb
, "Cannot read block bitmap - "
446 "block_group = %u, block_bitmap = %llu",
447 block_group
, (unsigned long long) bh
->b_blocknr
);
450 clear_buffer_new(bh
);
451 /* Panic or remount fs read-only if block bitmap is invalid */
452 ext4_validate_block_bitmap(sb
, desc
, block_group
, bh
);
457 ext4_read_block_bitmap(struct super_block
*sb
, ext4_group_t block_group
)
459 struct buffer_head
*bh
;
461 bh
= ext4_read_block_bitmap_nowait(sb
, block_group
);
462 if (ext4_wait_block_bitmap(sb
, block_group
, bh
)) {
470 * ext4_has_free_clusters()
471 * @sbi: in-core super block structure.
472 * @nclusters: number of needed blocks
473 * @flags: flags from ext4_mb_new_blocks()
475 * Check if filesystem has nclusters free & available for allocation.
476 * On success return 1, return 0 on failure.
478 static int ext4_has_free_clusters(struct ext4_sb_info
*sbi
,
479 s64 nclusters
, unsigned int flags
)
481 s64 free_clusters
, dirty_clusters
, root_clusters
;
482 struct percpu_counter
*fcc
= &sbi
->s_freeclusters_counter
;
483 struct percpu_counter
*dcc
= &sbi
->s_dirtyclusters_counter
;
485 free_clusters
= percpu_counter_read_positive(fcc
);
486 dirty_clusters
= percpu_counter_read_positive(dcc
);
487 root_clusters
= EXT4_B2C(sbi
, ext4_r_blocks_count(sbi
->s_es
));
489 if (free_clusters
- (nclusters
+ root_clusters
+ dirty_clusters
) <
490 EXT4_FREECLUSTERS_WATERMARK
) {
491 free_clusters
= EXT4_C2B(sbi
, percpu_counter_sum_positive(fcc
));
492 dirty_clusters
= percpu_counter_sum_positive(dcc
);
494 /* Check whether we have space after accounting for current
495 * dirty clusters & root reserved clusters.
497 if (free_clusters
>= ((root_clusters
+ nclusters
) + dirty_clusters
))
500 /* Hm, nope. Are (enough) root reserved clusters available? */
501 if (uid_eq(sbi
->s_resuid
, current_fsuid()) ||
502 (!gid_eq(sbi
->s_resgid
, GLOBAL_ROOT_GID
) && in_group_p(sbi
->s_resgid
)) ||
503 capable(CAP_SYS_RESOURCE
) ||
504 (flags
& EXT4_MB_USE_ROOT_BLOCKS
)) {
506 if (free_clusters
>= (nclusters
+ dirty_clusters
))
513 int ext4_claim_free_clusters(struct ext4_sb_info
*sbi
,
514 s64 nclusters
, unsigned int flags
)
516 if (ext4_has_free_clusters(sbi
, nclusters
, flags
)) {
517 percpu_counter_add(&sbi
->s_dirtyclusters_counter
, nclusters
);
524 * ext4_should_retry_alloc()
526 * @retries number of attemps has been made
528 * ext4_should_retry_alloc() is called when ENOSPC is returned, and if
529 * it is profitable to retry the operation, this function will wait
530 * for the current or committing transaction to complete, and then
533 * if the total number of retries exceed three times, return FALSE.
535 int ext4_should_retry_alloc(struct super_block
*sb
, int *retries
)
537 if (!ext4_has_free_clusters(EXT4_SB(sb
), 1, 0) ||
539 !EXT4_SB(sb
)->s_journal
)
542 jbd_debug(1, "%s: retrying operation after ENOSPC\n", sb
->s_id
);
544 return jbd2_journal_force_commit_nested(EXT4_SB(sb
)->s_journal
);
548 * ext4_new_meta_blocks() -- allocate block for meta data (indexing) blocks
550 * @handle: handle to this transaction
552 * @goal: given target block(filesystem wide)
553 * @count: pointer to total number of clusters needed
556 * Return 1st allocated block number on success, *count stores total account
557 * error stores in errp pointer
559 ext4_fsblk_t
ext4_new_meta_blocks(handle_t
*handle
, struct inode
*inode
,
560 ext4_fsblk_t goal
, unsigned int flags
,
561 unsigned long *count
, int *errp
)
563 struct ext4_allocation_request ar
;
566 memset(&ar
, 0, sizeof(ar
));
567 /* Fill with neighbour allocated blocks */
570 ar
.len
= count
? *count
: 1;
573 ret
= ext4_mb_new_blocks(handle
, &ar
, errp
);
577 * Account for the allocated meta blocks. We will never
578 * fail EDQUOT for metdata, but we do account for it.
581 ext4_test_inode_state(inode
, EXT4_STATE_DELALLOC_RESERVED
)) {
582 spin_lock(&EXT4_I(inode
)->i_block_reservation_lock
);
583 EXT4_I(inode
)->i_allocated_meta_blocks
+= ar
.len
;
584 spin_unlock(&EXT4_I(inode
)->i_block_reservation_lock
);
585 dquot_alloc_block_nofail(inode
,
586 EXT4_C2B(EXT4_SB(inode
->i_sb
), ar
.len
));
592 * ext4_count_free_clusters() -- count filesystem free clusters
595 * Adds up the number of free clusters from each block group.
597 ext4_fsblk_t
ext4_count_free_clusters(struct super_block
*sb
)
599 ext4_fsblk_t desc_count
;
600 struct ext4_group_desc
*gdp
;
602 ext4_group_t ngroups
= ext4_get_groups_count(sb
);
604 struct ext4_super_block
*es
;
605 ext4_fsblk_t bitmap_count
;
607 struct buffer_head
*bitmap_bh
= NULL
;
609 es
= EXT4_SB(sb
)->s_es
;
614 for (i
= 0; i
< ngroups
; i
++) {
615 gdp
= ext4_get_group_desc(sb
, i
, NULL
);
618 desc_count
+= ext4_free_group_clusters(sb
, gdp
);
620 bitmap_bh
= ext4_read_block_bitmap(sb
, i
);
621 if (bitmap_bh
== NULL
)
624 x
= ext4_count_free(bitmap_bh
->b_data
,
625 EXT4_BLOCKS_PER_GROUP(sb
) / 8);
626 printk(KERN_DEBUG
"group %u: stored = %d, counted = %u\n",
627 i
, ext4_free_group_clusters(sb
, gdp
), x
);
631 printk(KERN_DEBUG
"ext4_count_free_clusters: stored = %llu"
632 ", computed = %llu, %llu\n",
633 EXT4_B2C(EXT4_SB(sb
), ext4_free_blocks_count(es
)),
634 desc_count
, bitmap_count
);
638 for (i
= 0; i
< ngroups
; i
++) {
639 gdp
= ext4_get_group_desc(sb
, i
, NULL
);
642 desc_count
+= ext4_free_group_clusters(sb
, gdp
);
649 static inline int test_root(ext4_group_t a
, int b
)
658 static int ext4_group_sparse(ext4_group_t group
)
664 return (test_root(group
, 7) || test_root(group
, 5) ||
665 test_root(group
, 3));
669 * ext4_bg_has_super - number of blocks used by the superblock in group
670 * @sb: superblock for filesystem
671 * @group: group number to check
673 * Return the number of blocks used by the superblock (primary or backup)
674 * in this group. Currently this will be only 0 or 1.
676 int ext4_bg_has_super(struct super_block
*sb
, ext4_group_t group
)
678 if (EXT4_HAS_RO_COMPAT_FEATURE(sb
,
679 EXT4_FEATURE_RO_COMPAT_SPARSE_SUPER
) &&
680 !ext4_group_sparse(group
))
685 static unsigned long ext4_bg_num_gdb_meta(struct super_block
*sb
,
688 unsigned long metagroup
= group
/ EXT4_DESC_PER_BLOCK(sb
);
689 ext4_group_t first
= metagroup
* EXT4_DESC_PER_BLOCK(sb
);
690 ext4_group_t last
= first
+ EXT4_DESC_PER_BLOCK(sb
) - 1;
692 if (group
== first
|| group
== first
+ 1 || group
== last
)
697 static unsigned long ext4_bg_num_gdb_nometa(struct super_block
*sb
,
700 if (!ext4_bg_has_super(sb
, group
))
703 if (EXT4_HAS_INCOMPAT_FEATURE(sb
,EXT4_FEATURE_INCOMPAT_META_BG
))
704 return le32_to_cpu(EXT4_SB(sb
)->s_es
->s_first_meta_bg
);
706 return EXT4_SB(sb
)->s_gdb_count
;
710 * ext4_bg_num_gdb - number of blocks used by the group table in group
711 * @sb: superblock for filesystem
712 * @group: group number to check
714 * Return the number of blocks used by the group descriptor table
715 * (primary or backup) in this group. In the future there may be a
716 * different number of descriptor blocks in each group.
718 unsigned long ext4_bg_num_gdb(struct super_block
*sb
, ext4_group_t group
)
720 unsigned long first_meta_bg
=
721 le32_to_cpu(EXT4_SB(sb
)->s_es
->s_first_meta_bg
);
722 unsigned long metagroup
= group
/ EXT4_DESC_PER_BLOCK(sb
);
724 if (!EXT4_HAS_INCOMPAT_FEATURE(sb
,EXT4_FEATURE_INCOMPAT_META_BG
) ||
725 metagroup
< first_meta_bg
)
726 return ext4_bg_num_gdb_nometa(sb
, group
);
728 return ext4_bg_num_gdb_meta(sb
,group
);
733 * This function returns the number of file system metadata clusters at
734 * the beginning of a block group, including the reserved gdt blocks.
736 static unsigned ext4_num_base_meta_clusters(struct super_block
*sb
,
737 ext4_group_t block_group
)
739 struct ext4_sb_info
*sbi
= EXT4_SB(sb
);
742 /* Check for superblock and gdt backups in this group */
743 num
= ext4_bg_has_super(sb
, block_group
);
745 if (!EXT4_HAS_INCOMPAT_FEATURE(sb
, EXT4_FEATURE_INCOMPAT_META_BG
) ||
746 block_group
< le32_to_cpu(sbi
->s_es
->s_first_meta_bg
) *
747 sbi
->s_desc_per_block
) {
749 num
+= ext4_bg_num_gdb(sb
, block_group
);
750 num
+= le16_to_cpu(sbi
->s_es
->s_reserved_gdt_blocks
);
752 } else { /* For META_BG_BLOCK_GROUPS */
753 num
+= ext4_bg_num_gdb(sb
, block_group
);
755 return EXT4_NUM_B2C(sbi
, num
);
758 * ext4_inode_to_goal_block - return a hint for block allocation
759 * @inode: inode for block allocation
761 * Return the ideal location to start allocating blocks for a
762 * newly created inode.
764 ext4_fsblk_t
ext4_inode_to_goal_block(struct inode
*inode
)
766 struct ext4_inode_info
*ei
= EXT4_I(inode
);
767 ext4_group_t block_group
;
768 ext4_grpblk_t colour
;
769 int flex_size
= ext4_flex_bg_size(EXT4_SB(inode
->i_sb
));
770 ext4_fsblk_t bg_start
;
771 ext4_fsblk_t last_block
;
773 block_group
= ei
->i_block_group
;
774 if (flex_size
>= EXT4_FLEX_SIZE_DIR_ALLOC_SCHEME
) {
776 * If there are at least EXT4_FLEX_SIZE_DIR_ALLOC_SCHEME
777 * block groups per flexgroup, reserve the first block
778 * group for directories and special files. Regular
779 * files will start at the second block group. This
780 * tends to speed up directory access and improves
783 block_group
&= ~(flex_size
-1);
784 if (S_ISREG(inode
->i_mode
))
787 bg_start
= ext4_group_first_block_no(inode
->i_sb
, block_group
);
788 last_block
= ext4_blocks_count(EXT4_SB(inode
->i_sb
)->s_es
) - 1;
791 * If we are doing delayed allocation, we don't need take
792 * colour into account.
794 if (test_opt(inode
->i_sb
, DELALLOC
))
797 if (bg_start
+ EXT4_BLOCKS_PER_GROUP(inode
->i_sb
) <= last_block
)
798 colour
= (current
->pid
% 16) *
799 (EXT4_BLOCKS_PER_GROUP(inode
->i_sb
) / 16);
801 colour
= (current
->pid
% 16) * ((last_block
- bg_start
) / 16);
802 return bg_start
+ colour
;