From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1946475Ab2I1Vxf (ORCPT ); Fri, 28 Sep 2012 17:53:35 -0400 Received: from mail-pb0-f46.google.com ([209.85.160.46]:34785 "EHLO mail-pb0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1031049Ab2I1UXY (ORCPT ); Fri, 28 Sep 2012 16:23:24 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Greg Kroah-Hartman , alan@lxorguk.ukuu.org.uk, Miklos Szeredi , Trond Myklebust , Linus Torvalds Subject: [ 036/218] vfs: dcache: use DCACHE_DENTRY_KILLED instead of DCACHE_DISCONNECTED in d_kill() Date: Fri, 28 Sep 2012 13:14:13 -0700 Message-Id: <20120928201505.541925637@linuxfoundation.org> X-Mailer: git-send-email 1.7.12.1.428.g652398a In-Reply-To: <20120928201501.208384923@linuxfoundation.org> References: <20120928201501.208384923@linuxfoundation.org> User-Agent: quilt/0.60-2.1.2 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Miklos Szeredi commit b161dfa6937ae46d50adce8a7c6b12233e96e7bd upstream. IBM reported a soft lockup after applying the fix for the rename_lock deadlock. Commit c83ce989cb5f ("VFS: Fix the nfs sillyrename regression in kernel 2.6.38") was found to be the culprit. The nfs sillyrename fix used DCACHE_DISCONNECTED to indicate that the dentry was killed. This flag can be set on non-killed dentries too, which results in infinite retries when trying to traverse the dentry tree. This patch introduces a separate flag: DCACHE_DENTRY_KILLED, which is only set in d_kill() and makes try_to_ascend() test only this flag. IBM reported successful test results with this patch. Signed-off-by: Miklos Szeredi Cc: Trond Myklebust Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- fs/dcache.c | 4 ++-- include/linux/dcache.h | 2 ++ 2 files changed, 4 insertions(+), 2 deletions(-) --- a/fs/dcache.c +++ b/fs/dcache.c @@ -373,7 +373,7 @@ static struct dentry *d_kill(struct dent * Inform try_to_ascend() that we are no longer attached to the * dentry tree */ - dentry->d_flags |= DCACHE_DISCONNECTED; + dentry->d_flags |= DCACHE_DENTRY_KILLED; if (parent) spin_unlock(&parent->d_lock); dentry_iput(dentry); @@ -1030,7 +1030,7 @@ static struct dentry *try_to_ascend(stru * or deletion */ if (new != old->d_parent || - (old->d_flags & DCACHE_DISCONNECTED) || + (old->d_flags & DCACHE_DENTRY_KILLED) || (!locked && read_seqretry(&rename_lock, seq))) { spin_unlock(&new->d_lock); new = NULL; --- a/include/linux/dcache.h +++ b/include/linux/dcache.h @@ -191,6 +191,8 @@ struct dentry_operations { #define DCACHE_MANAGED_DENTRY \ (DCACHE_MOUNTED|DCACHE_NEED_AUTOMOUNT|DCACHE_MANAGE_TRANSIT) +#define DCACHE_DENTRY_KILLED 0x100000 + extern seqlock_t rename_lock; static inline int dname_external(struct dentry *dentry)