This is a note to let you know that I've just added the patch titled
ext4: fix inconsistent between segment fstrim and full fstrim
to the 5.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
ext4-fix-inconsistent-between-segment-fstrim-and-ful.patch
and it can be found in the queue-5.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 743b337ca7ba0833d15fe93c646ff8989e75c650
Author: Ye Bin <yebin10@xxxxxxxxxx>
Date: Sat Dec 16 09:09:19 2023 +0800
ext4: fix inconsistent between segment fstrim and full fstrim
[ 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@xxxxxxxxxx>
Reviewed-by: Jan Kara <jack@xxxxxxx>
Link: https://lore.kernel.org/r/20231216010919.1995851-1-yebin10@xxxxxxxxxx
Signed-off-by: Theodore Ts'o <tytso@xxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index a82ebc746cc4..762c2f8b5b2a 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -6457,13 +6457,15 @@ static int ext4_try_to_trim_range(struct super_block *sb,
__acquires(ext4_group_lock_ptr(sb, e4b->bd_group))
__releases(ext4_group_lock_ptr(sb, e4b->bd_group))
{
- 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;
@@ -6472,7 +6474,10 @@ __releases(ext4_group_lock_ptr(sb, e4b->bd_group))
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);
