From 48df498daf62e1292868005675331929305067f0 Mon Sep 17 00:00:00 2001 From: Guoqing Jiang Date: Tue, 14 Mar 2017 09:40:20 +0800 Subject: [PATCH] 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 ++++++++++++++++ drivers/md/bitmap.h | 1 + drivers/md/md.c | 13 ++----------- 3 files changed, 19 insertions(+), 11 deletions(-) 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 */ diff --git a/drivers/md/bitmap.h b/drivers/md/bitmap.h index 9f761097aab2..d15721ac07a6 100644 --- a/drivers/md/bitmap.h +++ b/drivers/md/bitmap.h @@ -271,6 +271,7 @@ struct bitmap *get_bitmap_from_slot(struct mddev *mddev, int slot); int bitmap_copy_from_slot(struct mddev *mddev, int slot, sector_t *lo, sector_t *hi, bool clear_bits); void bitmap_free(struct bitmap *bitmap); +void bitmap_wait_behind_writes(struct mddev *mddev); #endif #endif diff --git a/drivers/md/md.c b/drivers/md/md.c index af9118711228..42e68b2e0b41 100644 --- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -5675,15 +5675,7 @@ EXPORT_SYMBOL_GPL(md_stop_writes); static void mddev_detach(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); - } + bitmap_wait_behind_writes(mddev); if (mddev->pers && mddev->pers->quiesce) { mddev->pers->quiesce(mddev, 1); mddev->pers->quiesce(mddev, 0); @@ -5696,6 +5688,7 @@ static void mddev_detach(struct mddev *mddev) static void __md_stop(struct mddev *mddev) { struct md_personality *pers = mddev->pers; + bitmap_destroy(mddev); mddev_detach(mddev); /* Ensure ->event_work is done */ flush_workqueue(md_misc_wq); @@ -5716,7 +5709,6 @@ void md_stop(struct mddev *mddev) * This is called from dm-raid */ __md_stop(mddev); - bitmap_destroy(mddev); if (mddev->bio_set) bioset_free(mddev->bio_set); } @@ -5854,7 +5846,6 @@ static int do_md_stop(struct mddev *mddev, int mode, if (mode == 0) { pr_info("md: %s stopped.\n", mdname(mddev)); - bitmap_destroy(mddev); if (mddev->bitmap_info.file) { struct file *f = mddev->bitmap_info.file; spin_lock(&mddev->lock); -- 2.25.1