linux-stable.git/drivers/md/bcache, branch v5.4.2

Merge tag 'for-5.4/block-2019-09-16' of git://git.kernel.dk/linux-block

2019-09-17T23:57:47+00:00

Pull block updates from Jens Axboe:

 - Two NVMe pull requests:
     - ana log parse fix from Anton
     - nvme quirks support for Apple devices from Ben
     - fix missing bio completion tracing for multipath stack devices
       from Hannes and Mikhail
     - IP TOS settings for nvme rdma and tcp transports from Israel
     - rq_dma_dir cleanups from Israel
     - tracing for Get LBA Status command from Minwoo
     - Some nvme-tcp cleanups from Minwoo, Potnuri and Myself
     - Some consolidation between the fabrics transports for handling
       the CAP register
     - reset race with ns scanning fix for fabrics (move fabrics
       commands to a dedicated request queue with a different lifetime
       from the admin request queue)."
     - controller reset and namespace scan races fixes
     - nvme discovery log change uevent support
     - naming improvements from Keith
     - multiple discovery controllers reject fix from James
     - some regular cleanups from various people

 - Series fixing (and re-fixing) null_blk debug printing and nr_devices
   checks (André)

 - A few pull requests from Song, with fixes from Andy, Guoqing,
   Guilherme, Neil, Nigel, and Yufen.

 - REQ_OP_ZONE_RESET_ALL support (Chaitanya)

 - Bio merge handling unification (Christoph)

 - Pick default elevator correctly for devices with special needs
   (Damien)

 - Block stats fixes (Hou)

 - Timeout and support devices nbd fixes (Mike)

 - Series fixing races around elevator switching and device add/remove
   (Ming)

 - sed-opal cleanups (Revanth)

 - Per device weight support for BFQ (Fam)

 - Support for blk-iocost, a new model that can properly account cost of
   IO workloads. (Tejun)

 - blk-cgroup writeback fixes (Tejun)

 - paride queue init fixes (zhengbin)

 - blk_set_runtime_active() cleanup (Stanley)

 - Block segment mapping optimizations (Bart)

 - lightnvm fixes (Hans/Minwoo/YueHaibing)

 - Various little fixes and cleanups

* tag 'for-5.4/block-2019-09-16' of git://git.kernel.dk/linux-block: (186 commits)
  null_blk: format pr_* logs with pr_fmt
  null_blk: match the type of parameter nr_devices
  null_blk: do not fail the module load with zero devices
  block: also check RQF_STATS in blk_mq_need_time_stamp()
  block: make rq sector size accessible for block stats
  bfq: Fix bfq linkage error
  raid5: use bio_end_sector in r5_next_bio
  raid5: remove STRIPE_OPS_REQ_PENDING
  md: add feature flag MD_FEATURE_RAID0_LAYOUT
  md/raid0: avoid RAID0 data corruption due to layout confusion.
  raid5: don't set STRIPE_HANDLE to stripe which is in batch list
  raid5: don't increment read_errors on EILSEQ return
  nvmet: fix a wrong error status returned in error log page
  nvme: send discovery log page change events to userspace
  nvme: add uevent variables for controller devices
  nvme: enable aen regardless of the presence of I/O queues
  nvme-fabrics: allow discovery subsystems accept a kato
  nvmet: Use PTR_ERR_OR_ZERO() in nvmet_init_discovery()
  nvme: Remove redundant assignment of cq vector
  nvme: Assign subsys instance from first ctrl
  ...

closures: fix a race on wakeup from closure_sync

2019-09-03T14:08:31+00:00

The race was when a thread using closure_sync() notices cl->s->done == 1
before the thread calling closure_put() calls wake_up_process(). Then,
it's possible for that thread to return and exit just before
wake_up_process() is called - so we're trying to wake up a process that
no longer exists.

rcu_read_lock() is sufficient to protect against this, as there's an rcu
barrier somewhere in the process teardown path.

Signed-off-by: Kent Overstreet 
Acked-by: Coly Li 
Signed-off-by: Jens Axboe

bcache: Fix an error code in bch_dump_read()

2019-09-03T14:08:29+00:00

The copy_to_user() function returns the number of bytes remaining to be
copied, but the intention here was to return -EFAULT if the copy fails.

Fixes: cafe56359144 ("bcache: A block layer cache")
Signed-off-by: Dan Carpenter 
Signed-off-by: Coly Li 
Signed-off-by: Jens Axboe

bcache: add cond_resched() in __bch_cache_cmp()

2019-09-03T14:08:28+00:00

Read /sys/fs/bcache//cacheN/priority_stats can take very long
time with huge cache after long run.

Signed-off-by: Shile Zhang 
Tested-by: Heitor Alves de Siqueira 
Signed-off-by: Coly Li 
Signed-off-by: Jens Axboe

bcache: Revert "bcache: use sysfs_match_string() instead of __sysfs_match_string()"

2019-08-09T13:37:33+00:00

This reverts commit 89e0341af082dbc170019f908846f4a424efc86b.

In drivers/md/bcache/sysfs.c:bch_snprint_string_list(), NULL pointer at
the end of list is necessary. Remove the NULL from last element of each
lists will cause the following panic,

[ 4340.455652] bcache: register_cache() registered cache device nvme0n1
[ 4340.464603] bcache: register_bdev() registered backing device sdk
[ 4421.587335] bcache: bch_cached_dev_run() cached dev sdk is running already
[ 4421.587348] bcache: bch_cached_dev_attach() Caching sdk as bcache0 on set 354e1d46-d99f-4d8b-870b-078b80dc88a6
[ 5139.247950] general protection fault: 0000 [#1] SMP NOPTI
[ 5139.247970] CPU: 9 PID: 5896 Comm: cat Not tainted 4.12.14-95.29-default #1 SLE12-SP4
[ 5139.247988] Hardware name: HPE ProLiant DL380 Gen10/ProLiant DL380 Gen10, BIOS U30 04/18/2019
[ 5139.248006] task: ffff888fb25c0b00 task.stack: ffff9bbacc704000
[ 5139.248021] RIP: 0010:string+0x21/0x70
[ 5139.248030] RSP: 0018:ffff9bbacc707bf0 EFLAGS: 00010286
[ 5139.248043] RAX: ffffffffa7e432e3 RBX: ffff8881c20da02a RCX: ffff0a00ffffff04
[ 5139.248058] RDX: 3f00656863616362 RSI: ffff8881c20db000 RDI: ffffffffffffffff
[ 5139.248075] RBP: ffff8881c20db000 R08: 0000000000000000 R09: ffff8881c20da02a
[ 5139.248090] R10: 0000000000000004 R11: 0000000000000000 R12: ffff9bbacc707c48
[ 5139.248104] R13: 0000000000000fd6 R14: ffffffffc0665855 R15: ffffffffc0665855
[ 5139.248119] FS:  00007faf253b8700(0000) GS:ffff88903f840000(0000) knlGS:0000000000000000
[ 5139.248137] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 5139.248149] CR2: 00007faf25395008 CR3: 0000000f72150006 CR4: 00000000007606e0
[ 5139.248164] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 5139.248179] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[ 5139.248193] PKRU: 55555554
[ 5139.248200] Call Trace:
[ 5139.248210]  vsnprintf+0x1fb/0x510
[ 5139.248221]  snprintf+0x39/0x40
[ 5139.248238]  bch_snprint_string_list.constprop.15+0x5b/0x90 [bcache]
[ 5139.248256]  __bch_cached_dev_show+0x44d/0x5f0 [bcache]
[ 5139.248270]  ? __alloc_pages_nodemask+0xb2/0x210
[ 5139.248284]  bch_cached_dev_show+0x2c/0x50 [bcache]
[ 5139.248297]  sysfs_kf_seq_show+0xbb/0x190
[ 5139.248308]  seq_read+0xfc/0x3c0
[ 5139.248317]  __vfs_read+0x26/0x140
[ 5139.248327]  vfs_read+0x87/0x130
[ 5139.248336]  SyS_read+0x42/0x90
[ 5139.248346]  do_syscall_64+0x74/0x160
[ 5139.248358]  entry_SYSCALL_64_after_hwframe+0x3d/0xa2
[ 5139.248370] RIP: 0033:0x7faf24eea370
[ 5139.248379] RSP: 002b:00007fff82d03f38 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
[ 5139.248395] RAX: ffffffffffffffda RBX: 0000000000020000 RCX: 00007faf24eea370
[ 5139.248411] RDX: 0000000000020000 RSI: 00007faf25396000 RDI: 0000000000000003
[ 5139.248426] RBP: 00007faf25396000 R08: 00000000ffffffff R09: 0000000000000000
[ 5139.248441] R10: 000000007c9d4d41 R11: 0000000000000246 R12: 00007faf25396000
[ 5139.248456] R13: 0000000000000003 R14: 0000000000000000 R15: 0000000000000fff
[ 5139.248892] Code: ff ff ff 0f 1f 80 00 00 00 00 49 89 f9 48 89 cf 48 c7 c0 e3 32 e4 a7 48 c1 ff 30 48 81 fa ff 0f 00 00 48 0f 46 d0 48 85 ff 74 45 <44> 0f b6 02 48 8d 42 01 45 84 c0 74 38 48 01 fa 4c 89 cf eb 0e

The simplest way to fix is to revert commit 89e0341af082 ("bcache: use
sysfs_match_string() instead of __sysfs_match_string()").

This bug was introduced in Linux v5.2, so this fix only applies to
Linux v5.2 is enough for stable tree maintainer.

Fixes: 89e0341af082 ("bcache: use sysfs_match_string() instead of __sysfs_match_string()")
Cc: stable@vger.kernel.org
Cc: Alexandru Ardelean 
Reported-by: Peifeng Lin 
Acked-by: Alexandru Ardelean 
Signed-off-by: Coly Li 
Signed-off-by: Jens Axboe

bcache: fix possible memory leak in bch_cached_dev_run()

2019-07-22T14:15:17+00:00

memory malloced in bch_cached_dev_run() and should be freed before
leaving from the error handling cases, otherwise it will cause
memory leak.

Fixes: 0b13efecf5f2 ("bcache: add return value check to bch_cached_dev_run()")
Signed-off-by: Wei Yongjun 
Signed-off-by: Coly Li 
Signed-off-by: Jens Axboe

bcache: add reclaimed_journal_buckets to struct cache_set

2019-06-28T13:39:18+00:00

Now we have counters for how many times jouranl is reclaimed, how many
times cached dirty btree nodes are flushed, but we don't know how many
jouranl buckets are really reclaimed.

This patch adds reclaimed_journal_buckets into struct cache_set, this
is an increasing only counter, to tell how many journal buckets are
reclaimed since cache set runs. From all these three counters (reclaim,
reclaimed_journal_buckets, flush_write), we can have idea how well
current journal space reclaim code works.

Signed-off-by: Coly Li 
Signed-off-by: Jens Axboe

bcache: performance improvement for btree_flush_write()

2019-06-28T13:39:18+00:00

This patch improves performance for btree_flush_write() in following
ways,
- Use another spinlock journal.flush_write_lock to replace the very
  hot journal.lock. We don't have to use journal.lock here, selecting
  candidate btree nodes takes a lot of time, hold journal.lock here will
  block other jouranling threads and drop the overall I/O performance.
- Only select flushing btree node from c->btree_cache list. When the
  machine has a large system memory, mca cache may have a huge number of
  cached btree nodes. Iterating all the cached nodes will take a lot
  of CPU time, and most of the nodes on c->btree_cache_freeable and
  c->btree_cache_freed lists are cleared and have need to flush. So only
  travel mca list c->btree_cache to select flushing btree node should be
  enough for most of the cases.
- Don't iterate whole c->btree_cache list, only reversely select first
  BTREE_FLUSH_NR btree nodes to flush. Iterate all btree nodes from
  c->btree_cache and select the oldest journal pin btree nodes consumes
  huge number of CPU cycles if the list is huge (push and pop a node
  into/out of a heap is expensive). The last several dirty btree nodes
  on the tail of c->btree_cache list are earlest allocated and cached
  btree nodes, they are relative to the oldest journal pin btree nodes.
  Therefore only flushing BTREE_FLUSH_NR btree nodes from tail of
  c->btree_cache probably includes the oldest journal pin btree nodes.

In my testing, the above change decreases 50%+ CPU consumption when
journal space is full. Some times IOPS drops to 0 for 5-8 seconds,
comparing blocking I/O for 120+ seconds in previous code, this is much
better. Maybe there is room to improve in future, but at this momment
the fix looks fine and performs well in my testing.

Signed-off-by: Coly Li 
Signed-off-by: Jens Axboe

bcache: fix race in btree_flush_write()

2019-06-28T13:39:18+00:00

There is a race between mca_reap(), btree_node_free() and journal code
btree_flush_write(), which results very rare and strange deadlock or
panic and are very hard to reproduce.

Let me explain how the race happens. In btree_flush_write() one btree
node with oldest journal pin is selected, then it is flushed to cache
device, the select-and-flush is a two steps operation. Between these two
steps, there are something may happen inside the race window,
- The selected btree node was reaped by mca_reap() and allocated to
  other requesters for other btree node.
- The slected btree node was selected, flushed and released by mca
  shrink callback bch_mca_scan().
When btree_flush_write() tries to flush the selected btree node, firstly
b->write_lock is held by mutex_lock(). If the race happens and the
memory of selected btree node is allocated to other btree node, if that
btree node's write_lock is held already, a deadlock very probably
happens here. A worse case is the memory of the selected btree node is
released, then all references to this btree node (e.g. b->write_lock)
will trigger NULL pointer deference panic.

This race was introduced in commit cafe56359144 ("bcache: A block layer
cache"), and enlarged by commit c4dc2497d50d ("bcache: fix high CPU
occupancy during journal"), which selected 128 btree nodes and flushed
them one-by-one in a quite long time period.

Such race is not easy to reproduce before. On a Lenovo SR650 server with
48 Xeon cores, and configure 1 NVMe SSD as cache device, a MD raid0
device assembled by 3 NVMe SSDs as backing device, this race can be
observed around every 10,000 times btree_flush_write() gets called. Both
deadlock and kernel panic all happened as aftermath of the race.

The idea of the fix is to add a btree flag BTREE_NODE_journal_flush. It
is set when selecting btree nodes, and cleared after btree nodes
flushed. Then when mca_reap() selects a btree node with this bit set,
this btree node will be skipped. Since mca_reap() only reaps btree node
without BTREE_NODE_journal_flush flag, such race is avoided.

Once corner case should be noticed, that is btree_node_free(). It might
be called in some error handling code path. For example the following
code piece from btree_split(),
        2149 err_free2:
        2150         bkey_put(b->c, &n2->key);
        2151         btree_node_free(n2);
        2152         rw_unlock(true, n2);
        2153 err_free1:
        2154         bkey_put(b->c, &n1->key);
        2155         btree_node_free(n1);
        2156         rw_unlock(true, n1);
At line 2151 and 2155, the btree node n2 and n1 are released without
mac_reap(), so BTREE_NODE_journal_flush also needs to be checked here.
If btree_node_free() is called directly in such error handling path,
and the selected btree node has BTREE_NODE_journal_flush bit set, just
delay for 1 us and retry again. In this case this btree node won't
be skipped, just retry until the BTREE_NODE_journal_flush bit cleared,
and free the btree node memory.

Fixes: cafe56359144 ("bcache: A block layer cache")
Signed-off-by: Coly Li 
Reported-and-tested-by: kbuild test robot 
Cc: stable@vger.kernel.org
Signed-off-by: Jens Axboe

bcache: remove retry_flush_write from struct cache_set

2019-06-28T13:39:18+00:00

In struct cache_set, retry_flush_write is added for commit c4dc2497d50d
("bcache: fix high CPU occupancy during journal") which is reverted in
previous patch.

Now it is useless anymore, and this patch removes it from bcache code.

Signed-off-by: Coly Li 
Signed-off-by: Jens Axboe