user/sven/linux.git/drivers/md, branch v4.9.80

bcache: check return value of register_shrinker

2018-02-03T16:05:37Z

[ Upstream commit 6c4ca1e36cdc1a0a7a84797804b87920ccbebf51 ] register_shrinker is now __must_check, so check it to kill a warning. Caller of bch_btree_cache_alloc in super.c appropriately checks return value so this is fully plumbed through. This V2 fixes checkpatch warnings and improves the commit description, as I was too hasty getting the previous version out. Signed-off-by: Michael Lyle Reviewed-by: Vojtech Pavlik Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

dm thin metadata: THIN_MAX_CONCURRENT_LOCKS should be 6

2018-01-23T18:57:09Z

commit 490ae017f54e55bde382d45ea24bddfb6d1a0aaf upstream. For btree removal, there is a corner case that a single thread could takes 6 locks which is more than THIN_MAX_CONCURRENT_LOCKS(5) and leads to deadlock. A btree removal might eventually call rebalance_children()->rebalance3() to rebalance entries of three neighbor child nodes when shadow_spine has already acquired two write locks. In rebalance3(), it tries to shadow and acquire the write locks of all three child nodes. However, shadowing a child node requires acquiring a read lock of the original child node and a write lock of the new block. Although the read lock will be released after block shadowing, shadowing the third child node in rebalance3() could still take the sixth lock. (2 write locks for shadow_spine + 2 write locks for the first two child nodes's shadow + 1 write lock for the last child node's shadow + 1 read lock for the last child node) Signed-off-by: Dennis Yang Acked-by: Joe Thornber Signed-off-by: Mike Snitzer Signed-off-by: Greg Kroah-Hartman

dm btree: fix serious bug in btree_split_beneath()

2018-01-23T18:57:08Z

commit bc68d0a43560e950850fc69b58f0f8254b28f6d6 upstream. When inserting a new key/value pair into a btree we walk down the spine of btree nodes performing the following 2 operations: i) space for a new entry ii) adjusting the first key entry if the new key is lower than any in the node. If the _root_ node is full, the function btree_split_beneath() allocates 2 new nodes, and redistibutes the root nodes entries between them. The root node is left with 2 entries corresponding to the 2 new nodes. btree_split_beneath() then adjusts the spine to point to one of the two new children. This means the first key is never adjusted if the new key was lower, ie. operation (ii) gets missed out. This can result in the new key being 'lost' for a period; until another low valued key is inserted that will uncover it. This is a serious bug, and quite hard to make trigger in normal use. A reproducing test case ("thin create devices-in-reverse-order") is available as part of the thin-provision-tools project: https://github.com/jthornber/thin-provisioning-tools/blob/master/functional-tests/device-mapper/dm-tests.scm#L593 Fix the issue by changing btree_split_beneath() so it no longer adjusts the spine. Instead it unlocks both the new nodes, and lets the main loop in btree_insert_raw() relock the appropriate one and make any neccessary adjustments. Reported-by: Monty Pavel Signed-off-by: Joe Thornber Signed-off-by: Mike Snitzer Signed-off-by: Greg Kroah-Hartman

dm bufio: fix shrinker scans when (nr_to_scan < retain_target)

2018-01-17T08:38:49Z

commit fbc7c07ec23c040179384a1f16b62b6030eb6bdd upstream. When system is under memory pressure it is observed that dm bufio shrinker often reclaims only one buffer per scan. This change fixes the following two issues in dm bufio shrinker that cause this behavior: 1. ((nr_to_scan - freed) <= retain_target) condition is used to terminate slab scan process. This assumes that nr_to_scan is equal to the LRU size, which might not be correct because do_shrink_slab() in vmscan.c calculates nr_to_scan using multiple inputs. As a result when nr_to_scan is less than retain_target (64) the scan will terminate after the first iteration, effectively reclaiming one buffer per scan and making scans very inefficient. This hurts vmscan performance especially because mutex is acquired/released every time dm_bufio_shrink_scan() is called. New implementation uses ((LRU size - freed) <= retain_target) condition for scan termination. LRU size can be safely determined inside __scan() because this function is called after dm_bufio_lock(). 2. do_shrink_slab() uses value returned by dm_bufio_shrink_count() to determine number of freeable objects in the slab. However dm_bufio always retains retain_target buffers in its LRU and will terminate a scan when this mark is reached. Therefore returning the entire LRU size from dm_bufio_shrink_count() is misleading because that does not represent the number of freeable objects that slab will reclaim during a scan. Returning (LRU size - retain_target) better represents the number of freeable objects in the slab. This way do_shrink_slab() returns 0 when (LRU size < retain_target) and vmscan will not try to scan this shrinker avoiding scans that will not reclaim any memory. Test: tested using Android device running /system/extras/alloc-stress that generates memory pressure and causes intensive shrinker scans Signed-off-by: Suren Baghdasaryan Signed-off-by: Mike Snitzer Signed-off-by: Greg Kroah-Hartman

raid5: Set R5_Expanded on parity devices as well as data.

2017-12-20T09:07:32Z

[ Upstream commit 235b6003fb28f0dd8e7ed8fbdb088bb548291766 ] When reshaping a fully degraded raid5/raid6 to a larger nubmer of devices, the new device(s) are not in-sync and so that can make the newly grown stripe appear to be "failed". To avoid this, we set the R5_Expanded flag to say "Even though this device is not fully in-sync, this block is safe so don't treat the device as failed for this stripe". This flag is set for data devices, not not for parity devices. Consequently, if you have a RAID6 with two devices that are partly recovered and a spare, and start a reshape to include the spare, then when the reshape gets past the point where the recovery was up to, it will think the stripes are failed and will get into an infinite loop, failing to make progress. So when contructing parity on an EXPAND_READY stripe, set R5_Expanded. Reported-by: Curt Signed-off-by: NeilBrown Signed-off-by: Shaohua Li Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

bcache: fix wrong cache_misses statistics

2017-12-20T09:07:30Z

[ Upstream commit c157313791a999646901b3e3c6888514ebc36d62 ] Currently, Cache missed IOs are identified by s->cache_miss, but actually, there are many situations that missed IOs are not assigned a value for s->cache_miss in cached_dev_cache_miss(), for example, a bypassed IO (s->iop.bypass = 1), or the cache_bio allocate failed. In these situations, it will go to out_put or out_submit, and s->cache_miss is null, which leads bch_mark_cache_accounting() to treat this IO as a hit IO. [ML: applied by 3-way merge] Signed-off-by: tang.junhui Reviewed-by: Michael Lyle Reviewed-by: Coly Li Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

bcache: explicitly destroy mutex while exiting

2017-12-20T09:07:30Z

[ Upstream commit 330a4db89d39a6b43f36da16824eaa7a7509d34d ] mutex_destroy does nothing most of time, but it's better to call it to make the code future proof and it also has some meaning for like mutex debug. As Coly pointed out in a previous review, bcache_exit() may not be able to handle all the references properly if userspace registers cache and backing devices right before bch_debug_init runs and bch_debug_init failes later. So not exposing userspace interface until everything is ready to avoid that issue. Signed-off-by: Liang Chen Reviewed-by: Michael Lyle Reviewed-by: Coly Li Reviewed-by: Eric Wheeler Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

md-cluster: free md_cluster_info if node leave cluster

2017-12-20T09:07:18Z

[ Upstream commit 9c8043f337f14d1743006dfc59c03e80a42e3884 ] To avoid memory leak, we need to free the cinfo which is allocated when node join cluster. Reviewed-by: NeilBrown Signed-off-by: Guoqing Jiang Signed-off-by: Shaohua Li Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

md: free unused memory after bitmap resize

2017-12-16T15:25:47Z

[ Upstream commit 0868b99c214a3d55486c700de7c3f770b7243e7c ] When bitmap is resized, the old kalloced chunks just are not released once the resized bitmap starts to use new space. This fixes in particular kmemleak reports like this one: unreferenced object 0xffff8f4311e9c000 (size 4096): comm "lvm", pid 19333, jiffies 4295263268 (age 528.265s) hex dump (first 32 bytes): 02 80 02 80 02 80 02 80 02 80 02 80 02 80 02 80 ................ 02 80 02 80 02 80 02 80 02 80 02 80 02 80 02 80 ................ backtrace: [] kmemleak_alloc+0x4a/0xa0 [] kmem_cache_alloc_trace+0x14e/0x2e0 [] bitmap_checkpage+0x7c/0x110 [] bitmap_get_counter+0x45/0xd0 [] bitmap_set_memory_bits+0x43/0xe0 [] bitmap_init_from_disk+0x23c/0x530 [] bitmap_load+0xbe/0x160 [] raid_preresume+0x203/0x2f0 [dm_raid] [] dm_table_resume_targets+0x4f/0xe0 [] dm_resume+0x122/0x140 [] dev_suspend+0x18f/0x290 [] ctl_ioctl+0x287/0x560 [] dm_ctl_ioctl+0x13/0x20 [] do_vfs_ioctl+0xa6/0x750 [] SyS_ioctl+0x79/0x90 [] entry_SYSCALL_64_fastpath+0x1f/0xc2 Signed-off-by: Zdenek Kabelac Signed-off-by: Shaohua Li Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

bcache: recover data from backing when data is clean

2017-12-09T21:01:46Z

commit e393aa2446150536929140739f09c6ecbcbea7f0 upstream. When we send a read request and hit the clean data in cache device, there is a situation called cache read race in bcache(see the commit in the tail of cache_look_up(), the following explaination just copy from there): The bucket we're reading from might be reused while our bio is in flight, and we could then end up reading the wrong data. We guard against this by checking (in bch_cache_read_endio()) if the pointer is stale again; if so, we treat it as an error (s->iop.error = -EINTR) and reread from the backing device (but we don't pass that error up anywhere) It should be noted that cache read race happened under normal circumstances, not the circumstance when SSD failed, it was counted and shown in /sys/fs/bcache/XXX/internal/cache_read_races. Without this patch, when we use writeback mode, we will never reread from the backing device when cache read race happened, until the whole cache device is clean, because the condition (s->recoverable && (dc && !atomic_read(&dc->has_dirty))) is false in cached_dev_read_error(). In this situation, the s->iop.error(= -EINTR) will be passed up, at last, user will receive -EINTR when it's bio end, this is not suitable, and wield to up-application. In this patch, we use s->read_dirty_data to judge whether the read request hit dirty data in cache device, it is safe to reread data from the backing device when the read request hit clean data. This can not only handle cache read race, but also recover data when failed read request from cache device. [edited by mlyle to fix up whitespace, commit log title, comment spelling] Fixes: d59b23795933 ("bcache: only permit to recovery read error when cache device is clean") Signed-off-by: Hua Rui Reviewed-by: Michael Lyle Reviewed-by: Coly Li Signed-off-by: Michael Lyle Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman