[PATCH 4.9 46/78] xfs: Fix per-inode DAX flag inheritance

From: Greg Kroah-Hartman
Date: Mon Sep 18 2017 - 05:16:37 EST


4.9-stable review patch. If anyone has any objections, please let me know.

------------------


From: Lukas Czerner <lczerner@xxxxxxxxxx>

commit 56bdf855e676f1f2ed7033f288f57dfd315725ba upstream.

According to the commit that implemented per-inode DAX flag:
commit 58f88ca2df72 ("xfs: introduce per-inode DAX enablement")
the flag is supposed to act as "inherit flag".

Currently this only works in the situations where parent directory
already has a flag in di_flags set, otherwise inheritance does not
work. This is because setting the XFS_DIFLAG2_DAX flag is done in a
wrong branch designated for di_flags, not di_flags2.

Fix this by moving the code to branch designated for setting di_flags2,
which does test for flags in di_flags2.

Fixes: 58f88ca2df72 ("xfs: introduce per-inode DAX enablement")
Signed-off-by: Lukas Czerner <lczerner@xxxxxxxxxx>
Reviewed-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
Signed-off-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
fs/xfs/xfs_inode.c | 12 +++++++-----
1 file changed, 7 insertions(+), 5 deletions(-)

--- a/fs/xfs/xfs_inode.c
+++ b/fs/xfs/xfs_inode.c
@@ -881,7 +881,6 @@ xfs_ialloc(
case S_IFREG:
case S_IFDIR:
if (pip && (pip->i_d.di_flags & XFS_DIFLAG_ANY)) {
- uint64_t di_flags2 = 0;
uint di_flags = 0;

if (S_ISDIR(mode)) {
@@ -918,20 +917,23 @@ xfs_ialloc(
di_flags |= XFS_DIFLAG_NODEFRAG;
if (pip->i_d.di_flags & XFS_DIFLAG_FILESTREAM)
di_flags |= XFS_DIFLAG_FILESTREAM;
- if (pip->i_d.di_flags2 & XFS_DIFLAG2_DAX)
- di_flags2 |= XFS_DIFLAG2_DAX;

ip->i_d.di_flags |= di_flags;
- ip->i_d.di_flags2 |= di_flags2;
}
if (pip &&
(pip->i_d.di_flags2 & XFS_DIFLAG2_ANY) &&
pip->i_d.di_version == 3 &&
ip->i_d.di_version == 3) {
+ uint64_t di_flags2 = 0;
+
if (pip->i_d.di_flags2 & XFS_DIFLAG2_COWEXTSIZE) {
- ip->i_d.di_flags2 |= XFS_DIFLAG2_COWEXTSIZE;
+ di_flags2 |= XFS_DIFLAG2_COWEXTSIZE;
ip->i_d.di_cowextsize = pip->i_d.di_cowextsize;
}
+ if (pip->i_d.di_flags2 & XFS_DIFLAG2_DAX)
+ di_flags2 |= XFS_DIFLAG2_DAX;
+
+ ip->i_d.di_flags2 |= di_flags2;
}
/* FALLTHROUGH */
case S_IFLNK: