From 48df498daf62e1292868005675331929305067f0 Mon Sep 17 00:00:00 2001 From: Guoqing Jiang Date: Tue, 14 Mar 2017 09:40:20 +0800 Subject: md: move bitmap_destroy to the beginning of __md_stop Since we have switched to sync way to handle METADATA_UPDATED msg for md-cluster, then process_metadata_update is depended on mddev->thread->wqueue. With the new change, clustered raid could possible hang if array received a METADATA_UPDATED msg after array unregistered mddev->thread, so we need to stop clustered raid (bitmap_destroy -> bitmap_free -> md_cluster_stop) earlier than unregister thread (mddev_detach -> md_unregister_thread). And this change should be safe for non-clustered raid since all writes are stopped before the destroy. Also in md_run, we activate the personality (pers->run()) before activating the bitmap (bitmap_create()). So it is pleasingly symmetric to stop the bitmap (bitmap_destroy()) before stopping the personality (__md_stop() calls pers->free()), we achieve this by move bitmap_destroy to the beginning of __md_stop. But we don't want to break the codes for waiting behind IO as Shaohua mentioned, so introduce bitmap_wait_behind_writes to call the codes, and call the new fun in both mddev_detach and bitmap_destroy, then we will not break original behind IO code and also fit the new condition well. Signed-off-by: Guoqing Jiang Signed-off-by: Shaohua Li --- drivers/md/bitmap.c | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) (limited to 'drivers/md/bitmap.c') diff --git a/drivers/md/bitmap.c b/drivers/md/bitmap.c index b6fa55a3cff8..cc7bbd21813e 100644 --- a/drivers/md/bitmap.c +++ b/drivers/md/bitmap.c @@ -1764,6 +1764,20 @@ void bitmap_free(struct bitmap *bitmap) } EXPORT_SYMBOL(bitmap_free); +void bitmap_wait_behind_writes(struct mddev *mddev) +{ + struct bitmap *bitmap = mddev->bitmap; + + /* wait for behind writes to complete */ + if (bitmap && atomic_read(&bitmap->behind_writes) > 0) { + pr_debug("md:%s: behind writes in progress - waiting to stop.\n", + mdname(mddev)); + /* need to kick something here to make sure I/O goes? */ + wait_event(bitmap->behind_wait, + atomic_read(&bitmap->behind_writes) == 0); + } +} + void bitmap_destroy(struct mddev *mddev) { struct bitmap *bitmap = mddev->bitmap; @@ -1771,6 +1785,8 @@ void bitmap_destroy(struct mddev *mddev) if (!bitmap) /* there was no bitmap */ return; + bitmap_wait_behind_writes(mddev); + mutex_lock(&mddev->bitmap_info.mutex); spin_lock(&mddev->lock); mddev->bitmap = NULL; /* disconnect from the md device */ -- cgit v1.2.3