mirrors/scoutfs
1
0
Fork 0
mirror of https://github.com/versity/scoutfs.git synced 2026-05-01 10:25:43 +00:00
Code Issues Packages Projects Releases Wiki Activity

Only clear trying inode deletion bit when set

Browse Source 
try_delete_inode_items() is responsible for making sure that it's safe
to delete an inode's persistent items.  One of the things it has to
check is that there isn't another deletion attempt on the inode in this
mount.  It sets a bit in lock data while it's working and backs off if
the bit is already set.

Unfortunately it was always clearing this bit as it exited, regardless
of whether it set it or not.  This would let the next attempt perform
the deletion again before the working task had finished.  This was often
not a problem because background orphan scanning is the only source of
regular concurrent deletion attempts.

But it's a big problem if a deletion attempt takes a very long time.  It
gives enough time for an orphan scan attempt to clear the bit then try
again and clobber on whoever is performing the very slow deletion.

I hit this in a test that built files with an absurd number of
fragmented extents.  The second concurrent orphan attempt was able to
proceed with deletion and performed a bunch of duplicate data extent
frees and caused corruption.

The fix is to only clear the bit if we set it.  Now all concurrent
attempts will back off until the first task is done.

Signed-off-by: Zach Brown <zab@versity.com>
This commit is contained in:
Zach Brown
2022-07-28 16:24:23 -07:00
parent acb94dd9b7
commit 1cbc927ccb
1 changed files with 3 additions and 1 deletions
Download Patch File Download Diff File Expand all files Collapse all files

4
kmod/src/inode.c
View File

@@ -1685,6 +1685,7 @@ static int try_delete_inode_items(struct super_block *sb, u64 ino)
struct scoutfs_lock *lock = NULL;
struct scoutfs_inode sinode;
struct scoutfs_key key;
bool clear_trying = false;
u64 group_nr;
int bit_nr;
int ret;
@@ -1704,6 +1705,7 @@ static int try_delete_inode_items(struct super_block *sb, u64 ino)
ret = 0;
goto out;
}
clear_trying = true;
/* can't delete if it's cached in local or remote mounts */
if (scoutfs_omap_test(sb, ino) || test_bit_le(bit_nr, ldata->map.bits)) {
@@ -1730,7 +1732,7 @@ static int try_delete_inode_items(struct super_block *sb, u64 ino)
ret = delete_inode_items(sb, ino, &sinode, lock, orph_lock);
out:
if (ldata)
if (clear_trying)
clear_bit(bit_nr, ldata->trying);
scoutfs_unlock(sb, lock, SCOUTFS_LOCK_WRITE);