diff options
| author | NeilBrown <neilb@suse.com> | 2017-10-19 12:17:16 +1100 |
|---|---|---|
| committer | Shaohua Li <shli@fb.com> | 2017-11-01 21:32:18 -0700 |
| commit | 4d5324f760aacaefeb721b172aa14bf66045c332 (patch) | |
| tree | 4115e3a5b37b7890c402d07ce551648b93f63844 /drivers/md/md.c | |
| parent | 230b55fa8d64007339319539f8f8e68114d08529 (diff) | |
md: always hold reconfig_mutex when calling mddev_suspend()
Most often mddev_suspend() is called with
reconfig_mutex held. Make this a requirement in
preparation a subsequent patch. Also require
reconfig_mutex to be held for mddev_resume(),
partly for symmetry and partly to guarantee
no races with incr/decr of mddev->suspend.
Taking the mutex in r5c_disable_writeback_async() is
a little tricky as this is called from a work queue
via log->disable_writeback_work, and flush_work()
is called on that while holding ->reconfig_mutex.
If the work item hasn't run before flush_work()
is called, the work function will not be able to
get the mutex.
So we use mddev_trylock() inside the wait_event() call, and have that
abort when conf->log is set to NULL, which happens before
flush_work() is called.
We wait in mddev->sb_wait and ensure this is woken
when any of the conditions change. This requires
waking mddev->sb_wait in mddev_unlock(). This is only
like to trigger extra wake_ups of threads that needn't
be woken when metadata is being written, and that
doesn't happen often enough that the cost would be
noticeable.
Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Shaohua Li <shli@fb.com>
Diffstat (limited to 'drivers/md/md.c')
| -rw-r--r-- | drivers/md/md.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/drivers/md/md.c b/drivers/md/md.c index 6f25e3f1a1cf..9767bb33df56 100644 --- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -344,6 +344,7 @@ static blk_qc_t md_make_request(struct request_queue *q, struct bio *bio) void mddev_suspend(struct mddev *mddev) { WARN_ON_ONCE(mddev->thread && current == mddev->thread->tsk); + lockdep_assert_held(&mddev->reconfig_mutex); if (mddev->suspended++) return; synchronize_rcu(); @@ -357,6 +358,7 @@ EXPORT_SYMBOL_GPL(mddev_suspend); void mddev_resume(struct mddev *mddev) { + lockdep_assert_held(&mddev->reconfig_mutex); if (--mddev->suspended) return; wake_up(&mddev->sb_wait); @@ -663,6 +665,7 @@ void mddev_unlock(struct mddev *mddev) */ spin_lock(&pers_lock); md_wakeup_thread(mddev->thread); + wake_up(&mddev->sb_wait); spin_unlock(&pers_lock); } EXPORT_SYMBOL_GPL(mddev_unlock); |