[PATCH] igrab() should check for I_CLEAR

When igrab() is calling __iget() on an inode it should check if
clear_inode() has been called on the inode already.  Otherwise there is a
race window between clear_inode() and destroy_inode() where igrab() calls
__iget() which leads to already free inodes on the inode lists.

Signed-off-by: Vandana Rungta <vandana@novell.com>
Signed-off-by: Jan Blunck <jblunck@suse.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fs/inode.c

@@ -709,7 +709,7 @@ EXPORT_SYMBOL(iunique);
 struct inode *igrab(struct inode *inode)
 {
 	spin_lock(&inode_lock);
-	if (!(inode->i_state & (I_FREEING|I_WILL_FREE)))
+	if (!(inode->i_state & (I_FREEING|I_CLEAR|I_WILL_FREE)))
 		__iget(inode);
 	else
 		/*