Zach Brown 1cbc927ccb Only clear trying inode deletion bit when set ...

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>

2022-07-29 11:25:01 -07:00

..

src

Only clear trying inode deletion bit when set

2022-07-29 11:25:01 -07:00

.gitignore

scoutfs: update rpm building infrastructure

2018-09-14 15:07:10 -07:00

Makefile

Filesystem version instead of format hash check

2021-01-15 10:53:00 -08:00

scoutfs-kmod.spec.in

scoutfs: update rpm building infrastructure

2018-09-14 15:07:10 -07:00