linux-stable.git/drivers/md, branch linux-5.14.y

md: update superblock after changing rdev flags in state_store

2021-11-17T10:03:51+00:00

[ Upstream commit 8b9e2291e355a0eafdd5b1e21a94a6659f24b351 ]

When the in memory flag is changed, we need to persist the change in the
rdev superblock flags. This is needed for "writemostly" and "failfast".

Reviewed-by: Li Feng 
Signed-off-by: Xiao Ni 
Signed-off-by: Song Liu 
Signed-off-by: Jens Axboe 
Signed-off-by: Sasha Levin

md/raid1: only allocate write behind bio for WriteMostly device

2021-11-17T10:03:33+00:00

commit fd3b6975e9c11c4fa00965f82a0bfbb3b7b44101 upstream.

Commit 6607cd319b6b91bff94e90f798a61c031650b514 ("raid1: ensure write
behind bio has less than BIO_MAX_VECS sectors") tried to guarantee the
size of behind bio is not bigger than BIO_MAX_VECS sectors.

Unfortunately the same calltrace still could happen since an array could
enable write-behind without write mostly device.

To match the manpage of mdadm (which says "write-behind is only attempted
on drives marked as write-mostly"), we need to check WriteMostly flag to
avoid such unexpected behavior.

[1]. https://bugzilla.kernel.org/show_bug.cgi?id=213181#c25

Cc: stable@vger.kernel.org # v5.12+
Cc: Jens Stutte 
Reported-by: Jens Stutte 
Signed-off-by: Guoqing Jiang 
Signed-off-by: Song Liu 
Signed-off-by: Jens Axboe 
Signed-off-by: Greg Kroah-Hartman

dm rq: don't queue request to blk-mq during DM suspend

2021-10-20T09:57:46+00:00

commit b4459b11e84092658fa195a2587aff3b9637f0e7 upstream.

DM uses blk-mq's quiesce/unquiesce to stop/start device mapper queue.

But blk-mq's unquiesce may come from outside events, such as elevator
switch, updating nr_requests or others, and request may come during
suspend, so simply ask for blk-mq to requeue it.

Fixes one kernel panic issue when running updating nr_requests and
dm-mpath suspend/resume stress test.

Cc: stable@vger.kernel.org
Signed-off-by: Ming Lei 
Signed-off-by: Mike Snitzer 
Signed-off-by: Greg Kroah-Hartman

dm: fix mempool NULL pointer race when completing IO

2021-10-20T09:57:46+00:00

commit d208b89401e073de986dc891037c5a668f5d5d95 upstream.

dm_io_dec_pending() calls end_io_acct() first and will then dec md
in-flight pending count. But if a task is swapping DM table at same
time this can result in a crash due to mempool->elements being NULL:

task1                             task2
do_resume
 ->do_suspend
  ->dm_wait_for_completion
                                  bio_endio
				   ->clone_endio
				    ->dm_io_dec_pending
				     ->end_io_acct
				      ->wakeup task1
 ->dm_swap_table
  ->__bind
   ->__bind_mempools
    ->bioset_exit
     ->mempool_exit
                                     ->free_io

[ 67.330330] Unable to handle kernel NULL pointer dereference at
virtual address 0000000000000000
......
[ 67.330494] pstate: 80400085 (Nzcv daIf +PAN -UAO)
[ 67.330510] pc : mempool_free+0x70/0xa0
[ 67.330515] lr : mempool_free+0x4c/0xa0
[ 67.330520] sp : ffffff8008013b20
[ 67.330524] x29: ffffff8008013b20 x28: 0000000000000004
[ 67.330530] x27: ffffffa8c2ff40a0 x26: 00000000ffff1cc8
[ 67.330535] x25: 0000000000000000 x24: ffffffdada34c800
[ 67.330541] x23: 0000000000000000 x22: ffffffdada34c800
[ 67.330547] x21: 00000000ffff1cc8 x20: ffffffd9a1304d80
[ 67.330552] x19: ffffffdada34c970 x18: 000000b312625d9c
[ 67.330558] x17: 00000000002dcfbf x16: 00000000000006dd
[ 67.330563] x15: 000000000093b41e x14: 0000000000000010
[ 67.330569] x13: 0000000000007f7a x12: 0000000034155555
[ 67.330574] x11: 0000000000000001 x10: 0000000000000001
[ 67.330579] x9 : 0000000000000000 x8 : 0000000000000000
[ 67.330585] x7 : 0000000000000000 x6 : ffffff80148b5c1a
[ 67.330590] x5 : ffffff8008013ae0 x4 : 0000000000000001
[ 67.330596] x3 : ffffff80080139c8 x2 : ffffff801083bab8
[ 67.330601] x1 : 0000000000000000 x0 : ffffffdada34c970
[ 67.330609] Call trace:
[ 67.330616] mempool_free+0x70/0xa0
[ 67.330627] bio_put+0xf8/0x110
[ 67.330638] dec_pending+0x13c/0x230
[ 67.330644] clone_endio+0x90/0x180
[ 67.330649] bio_endio+0x198/0x1b8
[ 67.330655] dec_pending+0x190/0x230
[ 67.330660] clone_endio+0x90/0x180
[ 67.330665] bio_endio+0x198/0x1b8
[ 67.330673] blk_update_request+0x214/0x428
[ 67.330683] scsi_end_request+0x2c/0x300
[ 67.330688] scsi_io_completion+0xa0/0x710
[ 67.330695] scsi_finish_command+0xd8/0x110
[ 67.330700] scsi_softirq_done+0x114/0x148
[ 67.330708] blk_done_softirq+0x74/0xd0
[ 67.330716] __do_softirq+0x18c/0x374
[ 67.330724] irq_exit+0xb4/0xb8
[ 67.330732] __handle_domain_irq+0x84/0xc0
[ 67.330737] gic_handle_irq+0x148/0x1b0
[ 67.330744] el1_irq+0xe8/0x190
[ 67.330753] lpm_cpuidle_enter+0x4f8/0x538
[ 67.330759] cpuidle_enter_state+0x1fc/0x398
[ 67.330764] cpuidle_enter+0x18/0x20
[ 67.330772] do_idle+0x1b4/0x290
[ 67.330778] cpu_startup_entry+0x20/0x28
[ 67.330786] secondary_start_kernel+0x160/0x170

Fix this by:
1) Establishing pointers to 'struct dm_io' members in
dm_io_dec_pending() so that they may be passed into end_io_acct()
_after_ free_io() is called.
2) Moving end_io_acct() after free_io().

Cc: stable@vger.kernel.org
Signed-off-by: Jiazi Li 
Signed-off-by: Mike Snitzer 
Signed-off-by: Greg Kroah-Hartman

md: fix a lock order reversal in md_alloc

2021-09-30T08:13:03+00:00

[ Upstream commit 7df835a32a8bedf7ce88efcfa7c9b245b52ff139 ]

Commit b0140891a8cea3 ("md: Fix race when creating a new md device.")
not only moved assigning mddev->gendisk before calling add_disk, which
fixes the races described in the commit log, but also added a
mddev->open_mutex critical section over add_disk and creation of the
md kobj.  Adding a kobject after add_disk is racy vs deleting the gendisk
right after adding it, but md already prevents against that by holding
a mddev->active reference.

On the other hand taking this lock added a lock order reversal with what
is not disk->open_mutex (used to be bdev->bd_mutex when the commit was
added) for partition devices, which need that lock for the internal open
for the partition scan, and a recent commit also takes it for
non-partitioned devices, leading to further lockdep splatter.

Fixes: b0140891a8ce ("md: Fix race when creating a new md device.")
Fixes: d62633873590 ("block: support delayed holder registration")
Reported-by: syzbot+fadc0aaf497e6a493b9f@syzkaller.appspotmail.com
Signed-off-by: Christoph Hellwig 
Tested-by: syzbot+fadc0aaf497e6a493b9f@syzkaller.appspotmail.com
Reviewed-by: NeilBrown 
Signed-off-by: Song Liu 
Signed-off-by: Sasha Levin

dm crypt: Avoid percpu_counter spinlock contention in crypt_page_alloc()

2021-09-18T11:43:23+00:00

commit 528b16bfc3ae5f11638e71b3b63a81f9999df727 upstream.

On systems with many cores using dm-crypt, heavy spinlock contention in
percpu_counter_compare() can be observed when the page allocation limit
for a given device is reached or close to be reached. This is due
to percpu_counter_compare() taking a spinlock to compute an exact
result on potentially many CPUs at the same time.

Switch to non-exact comparison of allocated and allowed pages by using
the value returned by percpu_counter_read_positive() to avoid taking
the percpu_counter spinlock.

This may over/under estimate the actual number of allocated pages by at
most (batch-1) * num_online_cpus().

Currently, batch is bounded by 32. The system on which this issue was
first observed has 256 CPUs and 512GB of RAM. With a 4k page size, this
change may over/under estimate by 31MB. With ~10G (2%) allowed dm-crypt
allocations, this seems an acceptable error. Certainly preferred over
running into the spinlock contention.

This behavior was reproduced on an EC2 c5.24xlarge instance with 96 CPUs
and 192GB RAM as follows, but can be provoked on systems with less CPUs
as well.

 * Disable swap
 * Tune vm settings to promote regular writeback
     $ echo 50 > /proc/sys/vm/dirty_expire_centisecs
     $ echo 25 > /proc/sys/vm/dirty_writeback_centisecs
     $ echo $((128 * 1024 * 1024)) > /proc/sys/vm/dirty_background_bytes

 * Create 8 dmcrypt devices based on files on a tmpfs
 * Create and mount an ext4 filesystem on each crypt devices
 * Run stress-ng --hdd 8 within one of above filesystems

Total %system usage collected from sysstat goes to ~35%. Write throughput
on the underlying loop device is ~2GB/s. perf profiling an individual
kworker kcryptd thread shows the following profile, indicating spinlock
contention in percpu_counter_compare():

    99.98%     0.00%  kworker/u193:46  [kernel.kallsyms]  [k] ret_from_fork
      |
      --ret_from_fork
        kthread
        worker_thread
        |
         --99.92%--process_one_work
            |
            |--80.52%--kcryptd_crypt
            |    |
            |    |--62.58%--mempool_alloc
            |    |  |
            |    |   --62.24%--crypt_page_alloc
            |    |     |
            |    |      --61.51%--__percpu_counter_compare
            |    |        |
            |    |         --61.34%--__percpu_counter_sum
            |    |           |
            |    |           |--58.68%--_raw_spin_lock_irqsave
            |    |           |  |
            |    |           |   --58.30%--native_queued_spin_lock_slowpath
            |    |           |
            |    |            --0.69%--cpumask_next
            |    |                |
            |    |                 --0.51%--_find_next_bit
            |    |
            |    |--10.61%--crypt_convert
            |    |          |
            |    |          |--6.05%--xts_crypt
            ...

After applying this patch and running the same test, %system usage is
lowered to ~7% and write throughput on the loop device increases
to ~2.7GB/s. perf report shows mempool_alloc() as ~8% rather than ~62%
in the profile and not hitting the percpu_counter() spinlock anymore.

    |--8.15%--mempool_alloc
    |    |
    |    |--3.93%--crypt_page_alloc
    |    |    |
    |    |     --3.75%--__alloc_pages
    |    |         |
    |    |          --3.62%--get_page_from_freelist
    |    |              |
    |    |               --3.22%--rmqueue_bulk
    |    |                   |
    |    |                    --2.59%--_raw_spin_lock
    |    |                      |
    |    |                       --2.57%--native_queued_spin_lock_slowpath
    |    |
    |     --3.05%--_raw_spin_lock_irqsave
    |               |
    |                --2.49%--native_queued_spin_lock_slowpath

Suggested-by: DJ Gregor 
Reviewed-by: Mikulas Patocka 
Signed-off-by: Arne Welzel 
Fixes: 5059353df86e ("dm crypt: limit the number of allocated pages")
Cc: stable@vger.kernel.org
Signed-off-by: Mike Snitzer 
Signed-off-by: Greg Kroah-Hartman

md/raid10: Remove unnecessary rcu_dereference in raid10_handle_discard

2021-09-15T08:02:35+00:00

commit 46d4703b1db4c86ab5acb2331b10df999f005e8e upstream.

We are seeing the following warning in raid10_handle_discard.
[  695.110751] =============================
[  695.131439] WARNING: suspicious RCU usage
[  695.151389] 4.18.0-319.el8.x86_64+debug #1 Not tainted
[  695.174413] -----------------------------
[  695.192603] drivers/md/raid10.c:1776 suspicious
rcu_dereference_check() usage!
[  695.225107] other info that might help us debug this:
[  695.260940] rcu_scheduler_active = 2, debug_locks = 1
[  695.290157] no locks held by mkfs.xfs/10186.

In the first loop of function raid10_handle_discard. It already
determines which disk need to handle discard request and add the
rdev reference count rdev->nr_pending. So the conf->mirrors will
not change until all bios come back from underlayer disks. It
doesn't need to use rcu_dereference to get rdev.

Cc: stable@vger.kernel.org
Fixes: d30588b2731f ('md/raid10: improve raid10 discard request')
Signed-off-by: Xiao Ni 
Acked-by: Guoqing Jiang 
Signed-off-by: Song Liu 
Signed-off-by: Greg Kroah-Hartman

raid1: ensure write behind bio has less than BIO_MAX_VECS sectors

2021-09-15T08:02:33+00:00

commit 6607cd319b6b91bff94e90f798a61c031650b514 upstream.

We can't split write behind bio with more than BIO_MAX_VECS sectors,
otherwise the below call trace was triggered because we could allocate
oversized write behind bio later.

[ 8.097936] bvec_alloc+0x90/0xc0
[ 8.098934] bio_alloc_bioset+0x1b3/0x260
[ 8.099959] raid1_make_request+0x9ce/0xc50 [raid1]
[ 8.100988] ? __bio_clone_fast+0xa8/0xe0
[ 8.102008] md_handle_request+0x158/0x1d0 [md_mod]
[ 8.103050] md_submit_bio+0xcd/0x110 [md_mod]
[ 8.104084] submit_bio_noacct+0x139/0x530
[ 8.105127] submit_bio+0x78/0x1d0
[ 8.106163] ext4_io_submit+0x48/0x60 [ext4]
[ 8.107242] ext4_writepages+0x652/0x1170 [ext4]
[ 8.108300] ? do_writepages+0x41/0x100
[ 8.109338] ? __ext4_mark_inode_dirty+0x240/0x240 [ext4]
[ 8.110406] do_writepages+0x41/0x100
[ 8.111450] __filemap_fdatawrite_range+0xc5/0x100
[ 8.112513] file_write_and_wait_range+0x61/0xb0
[ 8.113564] ext4_sync_file+0x73/0x370 [ext4]
[ 8.114607] __x64_sys_fsync+0x33/0x60
[ 8.115635] do_syscall_64+0x33/0x40
[ 8.116670] entry_SYSCALL_64_after_hwframe+0x44/0xae

Thanks for the comment from Christoph.

[1]. https://bugs.archlinux.org/task/70992

Cc: stable@vger.kernel.org # v5.12+
Reported-by: Jens Stutte 
Tested-by: Jens Stutte 
Reviewed-by: Christoph Hellwig 
Signed-off-by: Guoqing Jiang 
Signed-off-by: Song Liu 
Signed-off-by: Greg Kroah-Hartman

bcache: add proper error unwinding in bcache_device_init

2021-09-15T08:02:03+00:00

[ Upstream commit 224b0683228c5f332f9cee615d85e75e9a347170 ]

Except for the IDA none of the allocations in bcache_device_init is
unwound on error, fix that.

Signed-off-by: Christoph Hellwig 
Acked-by: Coly Li 
Link: https://lore.kernel.org/r/20210809064028.1198327-7-hch@lst.de
Signed-off-by: Jens Axboe 
Signed-off-by: Sasha Levin

Merge tag 'block-5.14-2021-08-07' of git://git.kernel.dk/linux-block

2021-08-07T17:26:21+00:00

Pull block fixes from Jens Axboe:
 "A few minor fixes:

   - Fix ldm kernel-doc warning (Bart)

   - Fix adding offset twice for DMA address in n64cart (Christoph)

   - Fix use-after-free in dasd path handling (Stefan)

   - Order kyber insert trace correctly (Vincent)

   - raid1 errored write handling fix (Wei)

   - Fix blk-iolatency queue get failure handling (Yu)"

* tag 'block-5.14-2021-08-07' of git://git.kernel.dk/linux-block:
  kyber: make trace_block_rq call consistent with documentation
  block/partitions/ldm.c: Fix a kernel-doc warning
  blk-iolatency: error out if blk_get_queue() failed in iolatency_set_limit()
  n64cart: fix the dma address in n64cart_do_bvec
  s390/dasd: fix use after free in dasd path handling
  md/raid10: properly indicate failure when ending a failed write request