diff options
| author | Brian Foster <bfoster@redhat.com> | 2017-03-28 14:51:44 -0700 |
|---|---|---|
| committer | Sasha Levin <alexander.levin@verizon.com> | 2017-06-25 00:25:36 -0400 |
| commit | 74d27999c51e353fd0482c6750f98a7d3af2703d (patch) | |
| tree | 9ac32487c07f3190f7de88432b7b31928448a93b /fs | |
| parent | ddf2f45b3344be6f220229c500957078af21148f (diff) | |
xfs: use dedicated log worker wq to avoid deadlock with cil wq
[ Upstream commit 696a562072e3c14bcd13ae5acc19cdf27679e865 ]
The log covering background task used to be part of the xfssyncd
workqueue. That workqueue was removed as of commit 5889608df ("xfs:
syncd workqueue is no more") and the associated work item scheduled
to the xfs-log wq. The latter is used for log buffer I/O completion.
Since xfs_log_worker() can invoke a log flush, a deadlock is
possible between the xfs-log and xfs-cil workqueues. Consider the
following codepath from xfs_log_worker():
xfs_log_worker()
xfs_log_force()
_xfs_log_force()
xlog_cil_force()
xlog_cil_force_lsn()
xlog_cil_push_now()
flush_work()
The above is in xfs-log wq context and blocked waiting on the
completion of an xfs-cil work item. Concurrently, the cil push in
progress can end up blocked here:
xlog_cil_push_work()
xlog_cil_push()
xlog_write()
xlog_state_get_iclog_space()
xlog_wait(&log->l_flush_wait, ...)
The above is in xfs-cil context waiting on log buffer I/O
completion, which executes in xfs-log wq context. In this scenario
both workqueues are deadlocked waiting on eachother.
Add a new workqueue specifically for the high level log covering and
ail pushing worker, as was the case prior to commit 5889608df.
Diagnosed-by: David Jeffery <djeffery@redhat.com>
Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/xfs/xfs_log.c | 2 | ||||
| -rw-r--r-- | fs/xfs/xfs_mount.h | 1 | ||||
| -rw-r--r-- | fs/xfs/xfs_super.c | 8 |
3 files changed, 10 insertions, 1 deletions
diff --git a/fs/xfs/xfs_log.c b/fs/xfs/xfs_log.c index bcc7cfabb787..7ee735c0f490 100644 --- a/fs/xfs/xfs_log.c +++ b/fs/xfs/xfs_log.c @@ -1273,7 +1273,7 @@ void xfs_log_work_queue( struct xfs_mount *mp) { - queue_delayed_work(mp->m_log_workqueue, &mp->m_log->l_work, + queue_delayed_work(mp->m_sync_workqueue, &mp->m_log->l_work, msecs_to_jiffies(xfs_syncd_centisecs * 10)); } diff --git a/fs/xfs/xfs_mount.h b/fs/xfs/xfs_mount.h index 8c995a2ccb6f..9cccfd6f18c7 100644 --- a/fs/xfs/xfs_mount.h +++ b/fs/xfs/xfs_mount.h @@ -133,6 +133,7 @@ typedef struct xfs_mount { struct workqueue_struct *m_reclaim_workqueue; struct workqueue_struct *m_log_workqueue; struct workqueue_struct *m_eofblocks_workqueue; + struct workqueue_struct *m_sync_workqueue; /* * Generation of the filesysyem layout. This is incremented by each diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c index 2a517576f2bc..9ea51a71028e 100644 --- a/fs/xfs/xfs_super.c +++ b/fs/xfs/xfs_super.c @@ -853,8 +853,15 @@ xfs_init_mount_workqueues( if (!mp->m_eofblocks_workqueue) goto out_destroy_log; + mp->m_sync_workqueue = alloc_workqueue("xfs-sync/%s", WQ_FREEZABLE, 0, + mp->m_fsname); + if (!mp->m_sync_workqueue) + goto out_destroy_eofb; + return 0; +out_destroy_eofb: + destroy_workqueue(mp->m_eofblocks_workqueue); out_destroy_log: destroy_workqueue(mp->m_log_workqueue); out_destroy_reclaim: @@ -875,6 +882,7 @@ STATIC void xfs_destroy_mount_workqueues( struct xfs_mount *mp) { + destroy_workqueue(mp->m_sync_workqueue); destroy_workqueue(mp->m_eofblocks_workqueue); destroy_workqueue(mp->m_log_workqueue); destroy_workqueue(mp->m_reclaim_workqueue); |