[049/141] jfs: fix a couple races

Steven Rostedt
2013-07-03T18:41:17Z

[-- Attachment #1: 0049-jfs-fix-a-couple-races.patch --]
[-- Type: text/plain, Size: 1958 bytes --]

3.6.11.6 stable review patch.
If anyone has any objections, please let me know.

------------------

From: Dave Kleikamp <dave.kleikamp@oracle.com>

[ Upstream commit 73aaa22d5ffb2630456bac2f9a4ed9b81d0d7271 ]

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@gmail.com>
Signed-off-by: Dave Kleikamp <dave.kleikamp@oracle.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
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);
}

--
1.7.10.4