xfs: don't unconditionally clear the reflink flag on zero-block files

commit cc6f77710a upstream.

If we have speculative cow preallocations hanging around in the cow
fork, don't let a truncate operation clear the reflink flag because if
we do then there's a chance we'll forget to free those extents when we
destroy the incore inode.

Reported-by: Amir Goldstein <amir73il@gmail.com>
Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Darrick J. Wong 6 years ago committed by Greg Kroah-Hartman
parent 13c5e97701
commit 4e9de11c23

@ -1632,10 +1632,12 @@ xfs_itruncate_extents(
goto out;
* Clear the reflink flag if we truncated everything.
* Clear the reflink flag if there are no data fork blocks and
* there are no extents staged in the cow fork.
if (ip->i_d.di_nblocks == 0 && xfs_is_reflink_inode(ip)) {
ip->i_d.di_flags2 &= ~XFS_DIFLAG2_REFLINK;
if (xfs_is_reflink_inode(ip) && ip->i_cnextents == 0) {
if (ip->i_d.di_nblocks == 0)
ip->i_d.di_flags2 &= ~XFS_DIFLAG2_REFLINK;