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@gmail.com>
Signed-off-by: Dave Kleikamp <dave.kleikamp@oracle.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/fs/jfs/inode.c b/fs/jfs/inode.c
index 77b69b2..13fc885 100644 (file)
--- 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 cc5f811..bfb2a91 100644 (file)
--- 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);
 }