[ 3.5.y.z extended stable ] Patch "jfs: fix a couple races" has been added to staging queue

[Luis Henriques]

This is a note to let you know that I have just added a patch titled

    jfs: fix a couple races

to the linux-3.5.y-queue branch of the 3.5.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.5.y-queue

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.5.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

>From 01c06e7575360b15157ff26ff485aeeb1f9847d7 Mon Sep 17 00:00:00 2001
From: Dave Kleikamp <dave.kleikamp at oracle.com>
Date: Wed, 1 May 2013 11:08:38 -0500
Subject: [PATCH] jfs: fix a couple races

commit 73aaa22d5ffb2630456bac2f9a4ed9b81d0d7271 upstream.

This patch fixes races uncovered by xfstests testcase 068.

One race is the result of jfs_sync() trying to write a sync point to the
journal after it has been frozen (or possibly in the process). Since
freezing sync's the journal, there is no need to write a sync point so
we simply want to return.

The second involves jfs_write_inode() being called on a deleted inode.
It calls jfs_flush_journal which is held up by the jfs_commit thread
doing the final iput on the same deleted inode, which itself is
waiting for the I_SYNC flag to be cleared. jfs_write_inode need not
do anything when i_nlink is zero, which is the easy fix.

Reported-by: Michael L. Semon <mlsemon35 at gmail.com>
Signed-off-by: Dave Kleikamp <dave.kleikamp at oracle.com>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 fs/jfs/inode.c      | 2 +-
 fs/jfs/jfs_logmgr.c | 3 ++-
 2 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/fs/jfs/inode.c b/fs/jfs/inode.c
index 4692bf3..7e54dfd 100644
--- a/fs/jfs/inode.c
+++ b/fs/jfs/inode.c
@@ -125,7 +125,7 @@ int jfs_write_inode(struct inode *inode, struct writeback_control *wbc)
 {
 	int wait = wbc->sync_mode == WB_SYNC_ALL;

-	if (test_cflag(COMMIT_Nolink, inode))
+	if (inode->i_nlink == 0)
 		return 0;
 	/*
 	 * If COMMIT_DIRTY is not set, the inode isn't really dirty.
diff --git a/fs/jfs/jfs_logmgr.c b/fs/jfs/jfs_logmgr.c
index 2eb952c..cbe48ea 100644
--- a/fs/jfs/jfs_logmgr.c
+++ b/fs/jfs/jfs_logmgr.c
@@ -1058,7 +1058,8 @@ static int lmLogSync(struct jfs_log * log, int hard_sync)
  */
 void jfs_syncpt(struct jfs_log *log, int hard_sync)
 {	LOG_LOCK(log);
-	lmLogSync(log, hard_sync);
+	if (!test_bit(log_QUIESCE, &log->flag))
+		lmLogSync(log, hard_sync);
 	LOG_UNLOCK(log);
 }

--
1.8.1.2