From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S935240Ab2C3VHl (ORCPT ); Fri, 30 Mar 2012 17:07:41 -0400 Received: from mail-pb0-f46.google.com ([209.85.160.46]:34386 "EHLO mail-pb0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S935162Ab2C3VHc (ORCPT ); Fri, 30 Mar 2012 17:07:32 -0400 Message-Id: <20120330195734.352859498@linuxfoundation.org> User-Agent: quilt/0.60-19.1 Date: Fri, 30 Mar 2012 12:58:47 -0700 From: Greg KH To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, Michel Lespinasse Subject: [ 085/108] vfs: fix d_ancestor() case in d_materialize_unique In-Reply-To: <20120330195812.GA31833@kroah.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.0-stable review patch. If anyone has any objections, please let me know. ------------------ From: Michel Lespinasse commit b18dafc86bb879d2f38a1743985d7ceb283c2f4d upstream. In d_materialise_unique() there are 3 subcases to the 'aliased dentry' case; in two subcases the inode i_lock is properly released but this does not occur in the -ELOOP subcase. This seems to have been introduced by commit 1836750115f2 ("fix loop checks in d_materialise_unique()"). Signed-off-by: Michel Lespinasse [ Added a comment, and moved the unlock to where we generate the -ELOOP, which seems to be more natural. You probably can't actually trigger this without a buggy network file server - d_materialize_unique() is for finding aliases on non-local filesystems, and the d_ancestor() case is for a hardlinked directory loop. But we should be robust in the case of such buggy servers anyway. ] Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- fs/dcache.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/fs/dcache.c +++ b/fs/dcache.c @@ -2433,6 +2433,7 @@ struct dentry *d_materialise_unique(stru if (d_ancestor(alias, dentry)) { /* Check for loops */ actual = ERR_PTR(-ELOOP); + spin_unlock(&inode->i_lock); } else if (IS_ROOT(alias)) { /* Is this an anonymous mountpoint that we * could splice into our tree? */ @@ -2442,7 +2443,7 @@ struct dentry *d_materialise_unique(stru goto found; } else { /* Nope, but we must(!) avoid directory - * aliasing */ + * aliasing. This drops inode->i_lock */ actual = __d_unalias(inode, dentry, alias); } write_sequnlock(&rename_lock);