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Subject[PATCH v3 3/3] ext4: support flex_bg in ext4_mb_normalize_request
Date
In ext4_mb_normalize_request, the size of the allocation request is
limited to no more than EXT4_BLOCKS_PER_GROUP. Ritesh mentions that this
does not take into account the case of flex_bg groups. So we should add
support for flex_bg to make the physical blocks of large files contiguous.

Signed-off-by: Baokun Li <libaokun1@huawei.com>
---
fs/ext4/mballoc.c | 15 ++++++++++-----
1 file changed, 10 insertions(+), 5 deletions(-)

diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index 9e06334771a3..253fc250e9a0 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -4028,6 +4028,7 @@ ext4_mb_normalize_request(struct ext4_allocation_context *ac,
loff_t size, start_off;
loff_t orig_size __maybe_unused;
ext4_lblk_t start;
+ ext4_lblk_t bpg;
struct ext4_inode_info *ei = EXT4_I(ac->ac_inode);
struct ext4_prealloc_space *pa;

@@ -4051,6 +4052,11 @@ ext4_mb_normalize_request(struct ext4_allocation_context *ac,
}

bsbits = ac->ac_sb->s_blocksize_bits;
+ bpg = EXT4_BLOCKS_PER_GROUP(ac->ac_sb);
+ if (ext4_has_feature_flex_bg(ac->ac_sb) && sbi->s_log_groups_per_flex) {
+ if (check_shl_overflow(bpg, sbi->s_log_groups_per_flex, &bpg))
+ bpg = EXT_MAX_BLOCKS;
+ }

/* first, let's learn actual file size
* given current request is allocated */
@@ -4110,8 +4116,7 @@ ext4_mb_normalize_request(struct ext4_allocation_context *ac,
* alignment does not move allocation to a different group which
* makes mballoc fail assertions later.
*/
- start = max(start, rounddown(ac->ac_o_ex.fe_logical,
- (ext4_lblk_t)EXT4_BLOCKS_PER_GROUP(ac->ac_sb)));
+ start = max(start, rounddown(ac->ac_o_ex.fe_logical, bpg));

/* don't cover already allocated blocks in selected range */
if (ar->pleft && start <= ar->lleft) {
@@ -4125,8 +4130,8 @@ ext4_mb_normalize_request(struct ext4_allocation_context *ac,
* Trim allocation request for filesystems with artificially small
* groups.
*/
- if (size > EXT4_BLOCKS_PER_GROUP(ac->ac_sb))
- size = EXT4_BLOCKS_PER_GROUP(ac->ac_sb);
+ if (size > bpg)
+ size = bpg;

end = start + size;

@@ -4208,7 +4213,7 @@ ext4_mb_normalize_request(struct ext4_allocation_context *ac,
(unsigned long) ac->ac_o_ex.fe_logical);
BUG();
}
- BUG_ON(size <= 0 || size > EXT4_BLOCKS_PER_GROUP(ac->ac_sb));
+ BUG_ON(size <= 0 || size > bpg);

/* now prepare goal request */

--
2.31.1
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