xfs: don't be so eager to clear the cowblocks tag on truncate
Currently, xfs_itruncate_extents clears the cowblocks tag if i_cnextents
is zero. This is wrong, since i_cnextents only tracks real extents in
the CoW fork, which means that we could have some delayed CoW
reservations still in there that will now never get cleaned.
Fix a further bug where we /don't/ clear the reflink iflag if there are
any attribute blocks -- really, it's only safe to clear the reflink flag
if there are no data fork extents and no cow fork extents.
Found by adding clonerange to fsstress in xfs/017.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c
index b41952a..6f95bdb 100644
--- a/fs/xfs/xfs_inode.c
+++ b/fs/xfs/xfs_inode.c
@@ -1487,6 +1487,24 @@ xfs_link(
return error;
}
+/* Clear the reflink flag and the cowblocks tag if possible. */
+static void
+xfs_itruncate_clear_reflink_flags(
+ struct xfs_inode *ip)
+{
+ struct xfs_ifork *dfork;
+ struct xfs_ifork *cfork;
+
+ if (!xfs_is_reflink_inode(ip))
+ return;
+ dfork = XFS_IFORK_PTR(ip, XFS_DATA_FORK);
+ cfork = XFS_IFORK_PTR(ip, XFS_COW_FORK);
+ if (dfork->if_bytes == 0 && cfork->if_bytes == 0)
+ ip->i_d.di_flags2 &= ~XFS_DIFLAG2_REFLINK;
+ if (cfork->if_bytes == 0)
+ xfs_inode_clear_cowblocks_tag(ip);
+}
+
/*
* Free up the underlying blocks past new_size. The new size must be smaller
* than the current size. This routine can be used both for the attribute and
@@ -1583,15 +1601,7 @@ xfs_itruncate_extents(
if (error)
goto out;
- /*
- * Clear the reflink flag if there are no data fork blocks and
- * there are no extents staged in the cow fork.
- */
- 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);
- }
+ xfs_itruncate_clear_reflink_flags(ip);
/*
* Always re-log the inode so that our permanent transaction can keep