4.19-stable review patch. If anyone has any objections, please let me know.
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From: Ye Bin yebin10@huawei.com
[ Upstream commit 68da4c44b994aea797eb9821acb3a4a36015293e ]
Suppose we issue two FITRIM ioctls for ranges [0,15] and [16,31] with mininum length of trimmed range set to 8 blocks. If we have say a range of blocks 10-22 free, this range will not be trimmed because it straddles the boundary of the two FITRIM ranges and neither part is big enough. This is a bit surprising to some users that call FITRIM on smaller ranges of blocks to limit impact on the system. Also XFS trims all free space extents that overlap with the specified range so we are inconsistent among filesystems. Let's change ext4_try_to_trim_range() to consider for trimming the whole free space extent that straddles the end of specified range, not just the part of it within the range.
Signed-off-by: Ye Bin yebin10@huawei.com Reviewed-by: Jan Kara jack@suse.cz Link: https://lore.kernel.org/r/20231216010919.1995851-1-yebin10@huawei.com Signed-off-by: Theodore Ts'o tytso@mit.edu Signed-off-by: Sasha Levin sashal@kernel.org --- fs/ext4/mballoc.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-)
diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c index 0572ae09c729..df390979058f 100644 --- a/fs/ext4/mballoc.c +++ b/fs/ext4/mballoc.c @@ -5213,13 +5213,15 @@ static int ext4_try_to_trim_range(struct super_block *sb, struct ext4_buddy *e4b, ext4_grpblk_t start, ext4_grpblk_t max, ext4_grpblk_t minblocks) { - ext4_grpblk_t next, count, free_count; + ext4_grpblk_t next, count, free_count, last, origin_start; bool set_trimmed = false; void *bitmap;
+ last = ext4_last_grp_cluster(sb, e4b->bd_group); bitmap = e4b->bd_bitmap; - if (start == 0 && max >= ext4_last_grp_cluster(sb, e4b->bd_group)) + if (start == 0 && max >= last) set_trimmed = true; + origin_start = start; start = max(e4b->bd_info->bb_first_free, start); count = 0; free_count = 0; @@ -5228,7 +5230,10 @@ static int ext4_try_to_trim_range(struct super_block *sb, start = mb_find_next_zero_bit(bitmap, max + 1, start); if (start > max) break; - next = mb_find_next_bit(bitmap, max + 1, start); + + next = mb_find_next_bit(bitmap, last + 1, start); + if (origin_start == 0 && next >= last) + set_trimmed = true;
if ((next - start) >= minblocks) { int ret = ext4_trim_extent(sb, start, next - start, e4b);