reiserfs: turn of ATTR_KILL_S*ID at beginning of reiserfs_setattr

reiserfs_setattr can call notify_change recursively using the same
iattr struct. This could cause it to trip the BUG() in notify_change.
Fix reiserfs to clear those bits near the beginning of the function.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: Jeff Mahoney <jeffm@suse.com>
Cc: "Vladimir V. Saveliev" <vs@namesys.com>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fs/reiserfs/inode.c

@@ -3061,7 +3061,11 @@ int reiserfs_setattr(struct dentry *dentry, struct iattr *attr)
 {
 	struct inode *inode = dentry->d_inode;
 	int error;
-	unsigned int ia_valid = attr->ia_valid;
+	unsigned int ia_valid;
+
+	/* must be turned off for recursive notify_change calls */
+	ia_valid = attr->ia_valid &= ~(ATTR_KILL_SUID|ATTR_KILL_SGID);
+
 	reiserfs_write_lock(inode->i_sb);
 	if (attr->ia_valid & ATTR_SIZE) {
 		/* version 2 items will be caught by the s_maxbytes check