linux/drivers/md, branch v5.8

dm integrity: fix integrity recalculation that is improperly skipped

2020-07-23T18:39:37Z

Commit adc0daad366b62ca1bce3e2958a40b0b71a8b8b3 ("dm: report suspended device during destroy") broke integrity recalculation. The problem is dm_suspended() returns true not only during suspend, but also during resume. So this race condition could occur: 1. dm_integrity_resume calls queue_work(ic->recalc_wq, &ic->recalc_work) 2. integrity_recalc (&ic->recalc_work) preempts the current thread 3. integrity_recalc calls if (unlikely(dm_suspended(ic->ti))) goto unlock_ret; 4. integrity_recalc exits and no recalculating is done. To fix this race condition, add a function dm_post_suspending that is only true during the postsuspend phase and use it instead of dm_suspended(). Signed-off-by: Mikulas Patocka Fixes: adc0daad366b ("dm: report suspended device during destroy") Cc: stable vger kernel org # v4.18+ Signed-off-by: Mike Snitzer

dm: use noio when sending kobject event

2020-07-08T16:50:51Z

kobject_uevent may allocate memory and it may be called while there are dm devices suspended. The allocation may recurse into a suspended device, causing a deadlock. We must set the noio flag when sending a uevent. The observed deadlock was reported here: https://www.redhat.com/archives/dm-devel/2020-March/msg00025.html Reported-by: Khazhismel Kumykov Reported-by: Tahsin Erdogan Reported-by: Gabriel Krisman Bertazi Signed-off-by: Mikulas Patocka Cc: stable@vger.kernel.org Signed-off-by: Mike Snitzer

dm zoned: Fix zone reclaim trigger

2020-07-08T16:21:53Z

Only triggering reclaim based on the percentage of unmapped cache zones can fail to detect cases where reclaim is needed, e.g. if the target has only 2 or 3 cache zones and only one unmapped cache zone, the percentage of free cache zones is higher than DMZ_RECLAIM_LOW_UNMAP_ZONES (30%) and reclaim does not trigger. This problem, combined with the fact that dmz_schedule_reclaim() is called from dmz_handle_bio() without the map lock held, leads to a race between zone allocation and dmz_should_reclaim() result. Depending on the workload applied, this race can lead to the write path waiting forever for a free zone without reclaim being triggered. Fix this by moving dmz_schedule_reclaim() inside dmz_alloc_zone() under the map lock. This results in checking the need for zone reclaim whenever a new data or buffer zone needs to be allocated. Also fix dmz_reclaim_percentage() to always return 0 if the number of unmapped cache (or random) zones is less than or equal to 1. Suggested-by: Shin'ichiro Kawasaki Signed-off-by: Damien Le Moal Reviewed-by: Hannes Reinecke Signed-off-by: Mike Snitzer

dm zoned: fix unused but set variable warnings

2020-07-08T15:11:21Z

Fix unused but set variable warnings: drivers/md/dm-zoned-reclaim.c:504:42: warning: variable nr_rnd set but not used [-Wunused-but-set-variable] 504 | unsigned int p_unmap, nr_unmap_rnd = 0, nr_rnd = 0; | ^~~~~~ drivers/md/dm-zoned-reclaim.c:504:24: warning: variable nr_unmap_rnd set but not used [-Wunused-but-set-variable] 504 | unsigned int p_unmap, nr_unmap_rnd = 0, nr_rnd = 0; | ^~~~~~~~~~~~ Fixes: f97809aec589 ("dm zoned: per-device reclaim") Signed-off-by: Wei Yongjun Signed-off-by: Mike Snitzer

dm writecache: reject asynchronous pmem devices

2020-07-08T15:06:57Z

DM writecache does not handle asynchronous pmem. Reject it when supplied as cache. Link: https://lore.kernel.org/linux-nvdimm/87lfk5hahc.fsf@linux.ibm.com/ Fixes: 6e84200c0a29 ("virtio-pmem: Add virtio pmem driver") Signed-off-by: Michal Suchanek Acked-by: Mikulas Patocka Cc: stable@vger.kernel.org # 5.3+ Signed-off-by: Mike Snitzer

dm: use bio_uninit instead of bio_disassociate_blkg

2020-07-08T15:02:05Z

bio_uninit is the proper API to clean up a BIO that has been allocated on stack or inside a structure that doesn't come from the BIO allocator. Switch dm to use that instead of bio_disassociate_blkg, which really is an implementation detail. Note that the bio_uninit calls are also moved to the two callers of __send_empty_flush, so that they better pair with the bio_init calls used to initialize them. Signed-off-by: Christoph Hellwig Reviewed-by: Johannes Thumshirn Signed-off-by: Mike Snitzer

dm: do not use waitqueue for request-based DM

2020-07-07T16:00:01Z

Given request-based DM now uses blk-mq's blk_mq_queue_inflight() to determine if outstanding IO has completed (and DM has no control over the blk-mq state machine used to track outstanding IO) it is unsafe to wakeup waiter (dm_wait_for_completion) before blk-mq has cleared a request's state bits (e.g. MQ_RQ_IN_FLIGHT or MQ_RQ_COMPLETE). As such dm_wait_for_completion() could be left to wait indefinitely if no other requests complete. Fix this by eliminating request-based DM's use of waitqueue to wait for blk-mq requests to complete in dm_wait_for_completion. Signed-off-by: Ming Lei Depends-on: 3c94d83cb3526 ("blk-mq: change blk_mq_queue_busy() to blk_mq_queue_inflight()") Cc: stable@vger.kernel.org Signed-off-by: Mike Snitzer

Merge tag 'for-5.8/dm-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm

2020-06-27T15:57:16Z

Pull device mapper fixes from Mike Snitzer: - Quite a few DM zoned target fixes and a Zone append fix in DM core. Considering the amount of dm-zoned changes that went in during the 5.8 merge window these fixes are not that surprising. - A few DM writecache target fixes. - A fix to Documentation index to include DM ebs target docs. - Small cleanup to use struct_size() in DM core's retrieve_deps(). * tag 'for-5.8/dm-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm: dm writecache: add cond_resched to loop in persistent_memory_claim() dm zoned: Fix reclaim zone selection dm zoned: Fix random zone reclaim selection dm: update original bio sector on Zone Append dm zoned: Fix metadata zone size check docs: device-mapper: add dm-ebs.rst to an index file dm ioctl: use struct_size() helper in retrieve_deps() dm writecache: skip writecache_wait when using pmem mode dm writecache: correct uncommitted_block when discarding uncommitted entry dm zoned: assign max_io_len correctly dm zoned: fix uninitialized pointer dereference

dm writecache: add cond_resched to loop in persistent_memory_claim()

2020-06-19T16:32:24Z

Add cond_resched() to a loop that fills in the mapper memory area because the loop can be executed many times. Fixes: 48debafe4f2fe ("dm: add writecache target") Cc: stable@vger.kernel.org Signed-off-by: Mikulas Patocka Signed-off-by: Mike Snitzer

dm zoned: Fix reclaim zone selection

2020-06-19T16:29:39Z

When dm zoned has multiple devices, random zones are never selected for reclaim if all reserved sequential write zones are in use and no sequential write required zones can be selected for reclaim. This can lead to deadlocks as selecting a cache zone allows reclaiming a sequential zone, ensuring forward progress. Fix this by always defaulting to selecting a random zone when no sequential write required zone can be selected. [Damien: fix commit message] Signed-off-by: Shin'ichiro Kawasaki Signed-off-by: Damien Le Moal Reviewed-by: Hannes Reinecke Signed-off-by: Mike Snitzer