Commit cc6f7771 authored Sep 18, 2017 by Darrick J. Wong

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



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>

parent 2bd6bf03

fs/xfs/xfs_inode.c

+5 −3

Original line number	Diff line number	Diff line
		@@ -1624,9 +1624,11 @@ 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)) {
		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;
		xfs_inode_clear_cowblocks_tag(ip);
		}