commit 39772f0a7be3b3dc26c74ea13fe7847fd1522c8b upstream.

The locking protocols in md assume that a device will
never be removed from an array during resync/recovery/reshape.
When that isn't happening, rcu or reconfig_mutex is needed
to protect an rdev pointer while taking a refcount.  When
it is happening, that protection isn't needed.

Unfortunately there are cases were remove_and_add_spares() is
called when recovery might be happening: is state_store(),
slot_store() and hot_remove_disk().
In each case, this is just an optimization, to try to expedite
removal from the personality so the device can be removed from
the array.  If resync etc is happening, we just have to wait
for md_check_recover to find a suitable time to call
remove_and_add_spares().

This optimization and not essential so it doesn't
matter if it fails.
So change remove_and_add_spares() to abort early if
resync/recovery/reshape is happening, unless it is called
from md_check_recovery() as part of a newly started recovery.
The parameter "this" is only NULL when called from
md_check_recovery() so when it is NULL, there is no need to abort.

As this can result in a NULL dereference, the fix is suitable
for -stable.

cc: yuyufen <yuyufen@huawei.com>
Cc: Tomasz Majchrzak <tomasz.majchrzak@intel.com>
Fixes: 8430e7e0af9a ("md: disconnect device from personality before trying to remove it.")
Cc: stable@ver.kernel.org (v4.8+)
Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Shaohua Li <sh.li@alibaba-inc.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

There is a small window near the end of md_do_sync where mddev->curr_resync
can be equal to MaxSector.

If status_resync is called during this window, the resulting /proc/mdstat
output contains a HUGE number of = signs due to the very large curr_resync:

Personalities : [raid1]
md123 : active raid1 sdd3[2] sdb3[0]
  204736 blocks super 1.0 [2/1] [U_]
  [=====================================================================
   ... (82 MB more) ...
   ================>]  recovery =429496729.3% (9223372036854775807/204736)
   finish=0.2min speed=12796K/sec
  bitmap: 0/1 pages [0KB], 65536KB chunk

Modify status_resync to ensure the resync variable doesn't exceed
the array's max_sectors.

Signed-off-by: Nate Dailey <nate.dailey@stratus.com>
Acked-by: Guoqing Jiang <gqjiang@suse.com>
Signed-off-by: Shaohua Li <shli@fb.com>

Pull more block layer updates from Jens Axboe:
 "A followup pull request, with some parts that either needed a bit more
  testing before going in, merge sync, or just later arriving fixes.
  This contains:

   - Timer related updates from Kees. These were purposefully delayed
     since I didn't want to pull in a later v4.14-rc tag to my block
     tree.

   - ide-cd prep sense buffer fix from Bart. Also delayed, as not to
     clash with the late fix we put into 4.14-rc.

   - Small BFQ updates series from Luca and Paolo.

   - Single nvmet fix from James, fixing a non-functional case there.

   - Bio fast clone fix from Michael, which made bcache return the wrong
     data for some cases.

   - Legacy IO path regression hang fix from Ming"

* 'for-linus' of git://git.kernel.dk/linux-block:
  bio: ensure __bio_clone_fast copies bi_partno
  nvmet_fc: fix better length checking
  block: wake up all tasks blocked in get_request()
  block, bfq: move debug blkio stats behind CONFIG_DEBUG_BLK_CGROUP
  block, bfq: update blkio stats outside the scheduler lock
  block, bfq: add missing invocations of bfqg_stats_update_io_add/remove
  doc, block, bfq: update max IOPS sustainable with BFQ
  ide: Make ide_cdrom_prep_fs() initialize the sense buffer pointer
  md: Convert timers to use timer_setup()
  block: swim3: Convert timers to use timer_setup()
  block/aoe: Convert timers to use timer_setup()
  amifloppy: Convert timers to use timer_setup()
  block/floppy: Convert callback to pass timer_list

Pull module updates from Jessica Yu:
 "Summary of modules changes for the 4.15 merge window:

   - treewide module_param_call() cleanup, fix up set/get function
     prototype mismatches, from Kees Cook

   - minor code cleanups"

* tag 'modules-for-v4.15' of git://git.kernel.org/pub/scm/linux/kernel/git/jeyu/linux:
  module: Do not paper over type mismatches in module_param_call()
  treewide: Fix function prototypes for module_param_call()
  module: Prepare to convert all module_param_call() prototypes
  kernel/module: Delete an error message for a failed memory allocation in add_module_usage()

In preparation for unconditionally passing the struct timer_list pointer to
all timer callbacks, switch to using the new timer_setup() and from_timer()
to pass the timer pointer explicitly.

Cc: Kent Overstreet <kent.overstreet@gmail.com>
Cc: Shaohua Li <shli@kernel.org>
Cc: Alasdair Kergon <agk@redhat.com>
Cc: Mike Snitzer <snitzer@redhat.com>
Cc: dm-devel@redhat.com
Cc: linux-bcache@vger.kernel.org
Cc: linux-raid@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Michael Lyle <mlyle@lyle.org>
Reviewed-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Pull MD update from Shaohua Li:
 "This update mostly includes bug fixes:

   - md-cluster now supports raid10 from Guoqing

   - raid5 PPL fixes from Artur

   - badblock regression fix from Bo

   - suspend hang related fixes from Neil

   - raid5 reshape fixes from Neil

   - raid1 freeze deadlock fix from Nate

   - memleak fixes from Zdenek

   - bitmap related fixes from Me and Tao

   - other fixes and cleanups"

* 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/shli/md: (33 commits)
  md: free unused memory after bitmap resize
  md: release allocated bitset sync_set
  md/bitmap: clear BITMAP_WRITE_ERROR bit before writing it to sb
  md: be cautious about using ->curr_resync_completed for ->recovery_offset
  badblocks: fix wrong return value in badblocks_set if badblocks are disabled
  md: don't check MD_SB_CHANGE_CLEAN in md_allow_write
  md-cluster: update document for raid10
  md: remove redundant variable q
  raid1: remove obsolete code in raid1_write_request
  md-cluster: Use a small window for raid10 resync
  md-cluster: Suspend writes in RAID10 if within range
  md-cluster/raid10: set "do_balance = 0" if area is resyncing
  md: use lockdep_assert_held
  raid1: prevent freeze_array/wait_all_barriers deadlock
  md: use TASK_IDLE instead of blocking signals
  md: remove special meaning of ->quiesce(.., 2)
  md: allow metadata update while suspending.
  md: use mddev_suspend/resume instead of ->quiesce()
  md: move suspend_hi/lo handling into core md code
  md: don't call bitmap_create() while array is quiesced.
  ...

Patch fixes kmemleak on md_stop() path used likely only by dm-raid wrapper.
Code of md is using  mddev_put() where both bitsets are released however this
freeing is not shared.

Also set NULL to bio_set and sync_set pointers just like mddev_put is
doing.

Signed-off-by: Zdenek Kabelac <zkabelac@redhat.com>
Signed-off-by: Shaohua Li <shli@fb.com>

The ->recovery_offset shows how much of a non-InSync device is actually
in sync - how much has been recoveryed.

When performing a recovery, ->curr_resync and ->curr_resync_completed
follow the device address being recovered and so can be used to update
->recovery_offset.

When performing a reshape, ->curr_resync* might follow the device
addresses (raid5) or might follow array addresses (raid10), so cannot
in general be used to set ->recovery_offset.  When reshaping backwards,
->curre_resync* measures from the *end* of the array-or-device, so is
particularly unhelpful.

So change the common code in md.c to only use ->curr_resync_complete
for the simple recovery case, and add code to raid5.c to update
->recovery_offset during a forwards reshape.

Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Shaohua Li <shli@fb.com>

Only MD_SB_CHANGE_PENDING should be used to wait for transition from
clean to dirty. Checking also MD_SB_CHANGE_CLEAN is unnecessary and can
race with e.g. md_do_sync(). This sporadically causes a hang when
changing consistency policy during resync:

INFO: task mdadm:6183 blocked for more than 30 seconds.
      Not tainted 4.14.0-rc3+ #391
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
mdadm           D12752  6183   6022 0x00000000
Call Trace:
 __schedule+0x93f/0x990
 schedule+0x6b/0x90
 md_allow_write+0x100/0x130 [md_mod]
 ? do_wait_intr_irq+0x90/0x90
 resize_stripes+0x3a/0x5b0 [raid456]
 ? kernfs_fop_write+0xbe/0x180
 raid5_change_consistency_policy+0xa6/0x200 [raid456]
 consistency_policy_store+0x2e/0x70 [md_mod]
 md_attr_store+0x90/0xc0 [md_mod]
 sysfs_kf_write+0x42/0x50
 kernfs_fop_write+0x119/0x180
 __vfs_write+0x28/0x110
 ? rcu_sync_lockdep_assert+0x12/0x60
 ? __sb_start_write+0x15a/0x1c0
 ? vfs_write+0xa3/0x1a0
 vfs_write+0xb4/0x1a0
 SyS_write+0x49/0xa0
 entry_SYSCALL_64_fastpath+0x18/0xad

Fixes: 2214c260c72b ("md: don't return -EAGAIN in md_allow_write for external metadata arrays")
Cc: <stable@vger.kernel.org>
Signed-off-by: Artur Paszkiewicz <artur.paszkiewicz@intel.com>
Signed-off-by: Shaohua Li <shli@fb.com>

lockdep_assert_held is a better way to assert lock held, and it works
for UP.

Signed-off-by: Shaohua Li <shli@fb.com>