vfs: Add IOP_XATTR inode operations flag

The IOP_XATTR inode operations flag in inode->i_opflags indicates that
the inode has xattr support.  The flag is automatically set by
new_inode() on filesystems with xattr support (where sb->s_xattr is
defined), and cleared otherwise.  Filesystems can explicitly clear it
for inodes that should not have xattr support.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/inode.c b/fs/inode.c
index 7e3ef3a..705f860 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -140,6 +140,8 @@
 	inode->i_fop = &no_open_fops;
 	inode->__i_nlink = 1;
 	inode->i_opflags = 0;
+	if (sb->s_xattr)
+		inode->i_opflags |= IOP_XATTR;
 	i_uid_write(inode, 0);
 	i_gid_write(inode, 0);
 	atomic_set(&inode->i_writecount, 0);