[PATCH 1/4] xfs: XFS_DIFLAG_DAX is only for regular files or directories

[Dave Chinner]

From: Dave Chinner <dchinner at redhat.com>

Only file data can use DAX, so we should onyl be able to set this
flag on regular files. However, the flag also serves as an "inherit"
flag at file create time when set on directories, so limit the
FS_IOC_FSSETXATTR ioctl to only set this flag on regular files and
directories.

Signed-off-by: Dave Chinner <dchinner at redhat.com>
---
 fs/xfs/xfs_ioctl.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/fs/xfs/xfs_ioctl.c b/fs/xfs/xfs_ioctl.c
index 81d6d62..0895967 100644
--- a/fs/xfs/xfs_ioctl.c
+++ b/fs/xfs/xfs_ioctl.c
@@ -1051,6 +1051,14 @@ xfs_ioctl_setattr_xflags(
 	    !capable(CAP_LINUX_IMMUTABLE))
 		return -EPERM;
 
+	/*
+	 * It is only valid to set the DAX flag on regular files and
+	 * directories. On directories it serves as an inherit hint.
+	 */
+	if ((fa->fsx_xflags & FS_XFLAG_DAX) &&
+	    !(S_ISREG(VFS_I(ip)->i_mode) || S_ISDIR(VFS_I(ip)->i_mode)))
+		return -EINVAL;
+
 	xfs_set_diflags(ip, fa->fsx_xflags);
 	xfs_diflags_to_linux(ip);
 	xfs_trans_ichgtime(tp, ip, XFS_ICHGTIME_CHG);
-- 
2.5.0