From e8897529053d05f5bd677706ba6807fc2f2b942c Mon Sep 17 00:00:00 2001
From: Dave Chinner <dchinner@redhat.com>
Date: Tue, 1 Mar 2016 09:41:33 +1100
Subject: xfs: XFS_DIFLAG_DAX is only for regular files or directories

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@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Tested-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>

diff --git a/fs/xfs/xfs_ioctl.c b/fs/xfs/xfs_ioctl.c
index 478d04e..ee8f666 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);
-- 
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