xfs: Support setting FMODE_CAN_ATOMIC_WRITE

Set FMODE_CAN_ATOMIC_WRITE flag if we can atomic write for that inode.

Reviewed-by: Christoph Hellwig <[email protected]>
Reviewed-by: "Darrick J. Wong" <[email protected]>
Signed-off-by: John Garry <[email protected]>
Signed-off-by: Darrick J. Wong <[email protected]>
Reviewed-by: Jan Kara <[email protected]>
Reviewed-by: John Garry <[email protected]>
Tested-by: Ojaswin Mujoo <[email protected]>	 #On ppc64

Author: johnpgarry

fs/xfs/xfs_file.c

@@ -1223,6 +1223,8 @@ xfs_file_open(
 	if (xfs_is_shutdown(XFS_M(inode->i_sb)))
 		return -EIO;
 	file->f_mode |= FMODE_NOWAIT | FMODE_CAN_ODIRECT;
+	if (xfs_inode_can_atomicwrite(XFS_I(inode)))
+		file->f_mode |= FMODE_CAN_ATOMIC_WRITE;
 	return generic_file_open(inode, file);
 }