linux/drivers/md, branch v3.19

Merge tag 'md/3.19-fixes' of git://neil.brown.name/md

2015-02-04T03:54:57Z

Pull two fixes for md from Neil Brown: - Another live lock, needs backporting - work-around false positive with new warnings. * tag 'md/3.19-fixes' of git://neil.brown.name/md: md/bitmap: fix a might_sleep() warning. md/raid5: fix another livelock caused by non-aligned writes.

md/bitmap: fix a might_sleep() warning.

2015-02-02T06:08:03Z

commit 8eb23b9f35aae413140d3fda766a98092c21e9b0 sched: Debug nested sleeps causes false-positive warnings in RAID5 code. This annotation removes them and adds a comment explaining why there is no real problem. Reported-by: Fengguang Wu Signed-off-by: NeilBrown

md/raid5: fix another livelock caused by non-aligned writes.

2015-02-02T05:57:17Z

If a non-page-aligned write is destined for a device which is missing/faulty, we can deadlock. As the target device is missing, a read-modify-write cycle is not possible. As the write is not for a full-page, a recontruct-write cycle is not possible. This should be handled by logic in fetch_block() which notices there is a non-R5_OVERWRITE write to a missing device, and so loads all blocks. However since commit 67f455486d2ea2, that code requires STRIPE_PREREAD_ACTIVE before it will active, and those circumstances never set STRIPE_PREREAD_ACTIVE. So: in handle_stripe_dirtying, if neither rmw or rcw was possible, set STRIPE_DELAYED, which will cause STRIPE_PREREAD_ACTIVE be set after a suitable delay. Fixes: 67f455486d2ea20b2d94d6adf5b9b783d079e321 Cc: stable@vger.kernel.org (v3.16+) Reported-by: Mikulas Patocka Tested-by: Heinz Mauelshagen Signed-off-by: NeilBrown

dm thin: don't allow messages to be sent to a pool target in READ_ONLY or FAIL mode

2015-01-28T15:00:34Z

You can't modify the metadata in these modes. It's better to fail these messages immediately than let the block-manager deny write locks on metadata blocks. Otherwise these failed metadata changes will trigger 'needs_check' to get set in the metadata superblock -- requiring repair using the thin_check utility. Signed-off-by: Joe Thornber Signed-off-by: Mike Snitzer Cc: stable@vger.kernel.org

dm cache: fix missing ERR_PTR returns and handling

2015-01-28T14:59:20Z

Commit 9b1cc9f251 ("dm cache: share cache-metadata object across inactive and active DM tables") mistakenly ignored the use of ERR_PTR returns. Restore missing IS_ERR checks and ERR_PTR returns where appropriate. Reported-by: Dan Carpenter Signed-off-by: Joe Thornber Signed-off-by: Mike Snitzer Cc: stable@vger.kernel.org

dm: fix handling of multiple internal suspends

2015-01-24T19:50:08Z

Commit ffcc393641 ("dm: enhance internal suspend and resume interface") attempted to handle multiple internal suspends on the same device, but it did that incorrectly. When these functions are called in this order on the same device the device is no longer suspended, but it should be: dm_internal_suspend_noflush dm_internal_suspend_noflush dm_internal_resume Fix this bug by maintaining an 'internal_suspend_count' and resuming the device when this count drops to zero. Signed-off-by: Mikulas Patocka Signed-off-by: Mike Snitzer

dm cache: fix problematic dual use of a single migration count variable

2015-01-23T16:06:08Z

Introduce a new variable to count the number of allocated migration structures. The existing variable cache->nr_migrations became overloaded. It was used to: i) track of the number of migrations in flight for the purposes of quiescing during suspend. ii) to estimate the amount of background IO occuring. Recent discard changes meant that REQ_DISCARD bios are processed with a migration. Discards are not background IO so nr_migrations was not incremented. However this could cause quiescing to complete early. (i) is now handled with a new variable cache->nr_allocated_migrations. cache->nr_migrations has been renamed cache->nr_io_migrations. cleanup_migration() is now called free_io_migration(), since it decrements that variable. Also, remove the unused cache->next_migration variable that got replaced with with prealloc_structs a while ago. Signed-off-by: Joe Thornber Signed-off-by: Mike Snitzer Cc: stable@vger.kernel.org

dm cache: share cache-metadata object across inactive and active DM tables

2015-01-23T15:57:15Z

If a DM table is reloaded with an inactive table when the device is not suspended (normal procedure for LVM2), then there will be two dm-bufio objects that can diverge. This can lead to a situation where the inactive table uses bufio to read metadata at the same time the active table writes metadata -- resulting in the inactive table having stale metadata buffers once it is promoted to the active table slot. Fix this by using reference counting and a global list of cache metadata objects to ensure there is only one metadata object per metadata device. Signed-off-by: Joe Thornber Signed-off-by: Mike Snitzer Cc: stable@vger.kernel.org

dm: fix missed error code if .end_io isn't implemented by target_type

2014-12-17T17:31:13Z

In bio-based DM's clone_endio(), when target_type doesn't implement .end_io (e.g. linear) r will be always be initialized 0. So if a WRITE SAME bio fails WRITE SAME will not be disabled as intended. Fix this by initializing r to error, rather than 0, in clone_endio(). Signed-off-by: Alex Chen Signed-off-by: Mike Snitzer Fixes: 7eee4ae2db ("dm: disable WRITE SAME if it fails") Cc: stable@vger.kernel.org

dm thin: fix crash by initializing thin device's refcount and completion earlier

2014-12-17T17:06:25Z

Commit 80e96c5484be ("dm thin: do not allow thin device activation while pool is suspended") delayed the initialization of a new thin device's refcount and completion until after this new thin was added to the pool's active_thins list and the pool lock is released. This opens a race with a worker thread that walks the list and calls thin_get/put, noticing that the refcount goes to 0 and calling complete, freezing up the system and giving the oops below: kernel: BUG: unable to handle kernel NULL pointer dereference at (null) kernel: IP: [] __wake_up_common+0x2b/0x90 kernel: Call Trace: kernel: [] __wake_up_locked+0x13/0x20 kernel: [] complete+0x37/0x50 kernel: [] thin_put+0x20/0x30 [dm_thin_pool] kernel: [] do_worker+0x667/0x870 [dm_thin_pool] kernel: [] ? __schedule+0x3ac/0x9a0 kernel: [] process_one_work+0x14f/0x400 kernel: [] worker_thread+0x6b/0x490 kernel: [] ? rescuer_thread+0x260/0x260 kernel: [] kthread+0xdb/0x100 kernel: [] ? kthread_create_on_node+0x170/0x170 kernel: [] ret_from_fork+0x7c/0xb0 kernel: [] ? kthread_create_on_node+0x170/0x170 Set the thin device's initial refcount and initialize the completion before adding it to the pool's active_thins list in thin_ctr(). Signed-off-by: Marc Dionne Signed-off-by: Mike Snitzer