[PATCH 4.9 73/78] xfs: disable per-inode DAX flag

From: Greg Kroah-Hartman
Date: Mon Sep 18 2017 - 05:20:07 EST


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

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

From: Christoph Hellwig <hch@xxxxxx>

commit 742d84290739ae908f1b61b7d17ea382c8c0073a upstream.

Currently flag switching can be used to easily crash the kernel. Disable
the per-inode DAX flag until that is sorted out.

Signed-off-by: Christoph Hellwig <hch@xxxxxx>
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_ioctl.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

--- a/fs/xfs/xfs_ioctl.c
+++ b/fs/xfs/xfs_ioctl.c
@@ -1005,11 +1005,12 @@ xfs_diflags_to_linux(
inode->i_flags |= S_NOATIME;
else
inode->i_flags &= ~S_NOATIME;
+#if 0 /* disabled until the flag switching races are sorted out */
if (xflags & FS_XFLAG_DAX)
inode->i_flags |= S_DAX;
else
inode->i_flags &= ~S_DAX;
-
+#endif
}

static int