From a58a0826656d3159fd0cd0d8be63a80edf4dae07 Mon Sep 17 00:00:00 2001
From: "Darrick J. Wong" <darrick.wong@oracle.com>
Date: Mon, 18 Sep 2017 09:41:16 -0700
Subject: [PATCH] xfs: don't unconditionally clear the reflink flag on
zero-block files
References: bsc#1085535
Patch-mainline: v4.14-rc3
Git-commit: cc6f77710a6de6210f9feda7cd53e2f5ee7a7e69
Stable-commit: a58a0826656d3159fd0cd0d8be63a80edf4dae07
commit cc6f77710a6de6210f9feda7cd53e2f5ee7a7e69 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>
Signed-off-by: Luis R. Rodriguez <mcgrof@suse.com>
---
fs/xfs/xfs_inode.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)
diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c
index 97045e8dfed5..cd2e5b122b01 100644
--- a/fs/xfs/xfs_inode.c
+++ b/fs/xfs/xfs_inode.c
@@ -1623,10 +1623,12 @@ 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;
xfs_inode_clear_cowblocks_tag(ip);
}
--
2.16.2