bitmap_flush() finishes with bitmap_update_sb(), and that finishes
with write_page(..., 1), so write_page() will wait for all writes
to complete.  So there is no point calling md_super_wait()
immediately afterwards.
Signed-off-by: NNeilBrown <neilb@suse.com>
Signed-off-by: NShaohua Li <shli@fb.com>

When adding devices to, or removing device from, an array we need to
update the metadata.  However we don't need to do it synchronously as
data integrity doesn't depend on these changes being recorded
instantly.  So avoid the synchronous call to md_update_sb and just set
a flag so that the thread will do it.

This can reduce the number of updates performed when lots of devices
are being added or removed.
Signed-off-by: NNeilBrown <neilb@suse.com>
Signed-off-by: NShaohua Li <shli@fb.com>

1/ using pr_debug() for a number of messages reduces the noise of
   md, but still allows them to be enabled when needed.
2/ try to be consistent in the usage of pr_err() and pr_warn(), and
   document the intention
3/ When strings have been split onto multiple lines, rejoin into
   a single string.
   The cost of having lines > 80 chars is less than the cost of not
   being able to easily search for a particular message.
Signed-off-by: NNeilBrown <neilb@suse.com>
Signed-off-by: NShaohua Li <shli@fb.com>

1/ don't print a warning if allocation fails.
 page_alloc() does that already.
2/ always check return status for error.
Signed-off-by: NNeilBrown <neilb@suse.com>
Signed-off-by: NShaohua Li <shli@fb.com>

When raid1/raid10 array fails to write to one of the drives, the request
is added to bio_end_io_list and finished by personality thread. The
thread doesn't handle it as long as MD_CHANGE_PENDING flag is set. In
case of external metadata this flag is cleared, however the thread is
not woken up. It causes request to be blocked for few seconds (until
another action on the array wakes up the thread) or to get stuck
indefinitely.

Wake up personality thread once MD_CHANGE_PENDING has been cleared.
Moving 'restart_array' call after the flag is cleared it not a solution
because in read-write mode the call doesn't wake up the thread.
Signed-off-by: NTomasz Majchrzak <tomasz.majchrzak@intel.com>
Signed-off-by: NShaohua Li <shli@fb.com>

If external metadata handler supports bad blocks and unacknowledged bad
blocks are present, don't report disk via sysfs as faulty. Such
situation can be still handled so disk just has to be blocked for a
moment. It makes it consistent with kernel state as corresponding rdev
flag is also not set.

When the disk in being unblocked there are few cases:
1. Disk has been in blocked and faulty state, it is being unblocked but
it still remains in faulty state. Metadata handler will remove it from
array in the next call.
2. There is no bad block support in external metadata handler and bad
blocks are present - put the disk in blocked and faulty state (see
case 1).
3. There is bad block support in external metadata handler and all bad
blocks are acknowledged - clear all flags, continue.
4. There is bad block support in external metadata handler but there are
still unacknowledged bad blocks - clear all flags, continue. It is fine
to clear Blocked flag because it was probably not set anyway (if it was
it is case 1). BlockedBadBlocks flag can also be cleared because the
request waiting for it will set it again when it finds out that some bad
block is still not acknowledged. Recovery is not necessary but there are
no problems if the flag is set. Sysfs rdev state is still reported as
blocked (due to unacknowledged bad blocks) so metadata handler will
process remaining bad blocks and unblock disk again.
Signed-off-by: NTomasz Majchrzak <tomasz.majchrzak@intel.com>
Signed-off-by: NShaohua Li <shli@fb.com>

Add new rdev flag which external metadata handler can use to switch
on/off bad block support. If new bad block is encountered, notify it via
rdev 'unacknowledged_bad_blocks' sysfs file. If bad block has been
cleared, notify update to rdev 'bad_blocks' sysfs file.

When bad blocks support is being removed, just clear rdev flag. It is
not necessary to reset badblocks->shift field. If there are bad blocks
cleared or added at the same time, it is ok for those changes to be
applied to the structure. The array is in blocked state and the drive
which cannot handle bad blocks any more will be removed from the array
before it is unlocked.

Simplify state_show function by adding a separator at the end of each
string and overwrite last separator with new line.
Signed-off-by: NTomasz Majchrzak <tomasz.majchrzak@intel.com>
Reviewed-by: NArtur Paszkiewicz <artur.paszkiewicz@intel.com>
Signed-off-by: NShaohua Li <shli@fb.com>

mddev->curr_resync usually records where the current resync is up to,
but during the starting phase it has some "magic" values.

 1 - means that the array is trying to start a resync, but has yielded
     to another array which shares physical devices, and also needs to
     start a resync
 2 - means the array is trying to start resync, but has found another
     array which shares physical devices and has already started resync.

 3 - means that resync has commensed, but it is possible that nothing
     has actually been resynced yet.

It is important that this value not be visible to user-space and
particularly that it doesn't get written to the metadata, as the
resync or recovery checkpoint.  In part, this is because it may be
slightly higher than the correct value, though this is very rare.
In part, because it is not a multiple of 4K, and some devices only
support 4K aligned accesses.

There are two places where this value is propagates into either
->curr_resync_completed or ->recovery_cp or ->recovery_offset.
These currently avoid the propagation of values 1 and 3, but will
allow 3 to leak through.

Change them to only propagate the value if it is > 3.

As this can cause an array to fail, the patch is suitable for -stable.

Cc: stable@vger.kernel.org (v3.7+)
Reported-by: NViswesh <viswesh.vichu@gmail.com>
Signed-off-by: NNeilBrown <neilb@suse.com>
Signed-off-by: NShaohua Li <shli@fb.com>

If there is a bad block on a disk and there is a recovery performed from
this disk, the same bad block is reported for a new disk. It involves
setting MD_CHANGE_PENDING flag in rdev_set_badblocks. For external
metadata this flag is not being cleared as array state is reported as
'clean'. The read request to bad block in RAID5 array gets stuck as it
is waiting for a flag to be cleared - as per commit c3cce6cd
("md/raid5: ensure device failure recorded before write request
returns.").

The meaning of MD_CHANGE_PENDING and MD_CHANGE_CLEAN flags has been
clarified in commit 070dc6dd ("md: resolve confusion of
MD_CHANGE_CLEAN"), however MD_CHANGE_PENDING flag has been used in
personality error handlers since and it doesn't fully comply with
initial purpose. It was supposed to notify that write request is about
to start, however now it is also used to request metadata update.
Initially (in md_allow_write, md_write_start) MD_CHANGE_PENDING flag has
been set and in_sync has been set to 0 at the same time. Error handlers
just set the flag without modifying in_sync value. Sysfs array state is
a single value so now it reports 'clean' when MD_CHANGE_PENDING flag is
set and in_sync is set to 1. Userspace has no idea it is expected to
take some action.

Swap the order that array state is checked so 'write_pending' is
reported ahead of 'clean' ('write_pending' is a misleading name but it
is too late to rename it now).
Signed-off-by: NTomasz Majchrzak <tomasz.majchrzak@intel.com>
Signed-off-by: NShaohua Li <shli@fb.com>

if all disks in an array are non-rotational, set the array
non-rotational.

This only works for array with all disks populated at startup. Support
for disk hotadd/hotremove could be added later if necessary.
Acked-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NShaohua Li <shli@fb.com>

lockdep reports a potential deadlock. Fix this by droping the mutex
before md_import_device

[ 1137.126601] ======================================================
[ 1137.127013] [ INFO: possible circular locking dependency detected ]
[ 1137.127013] 4.8.0-rc4+ #538 Not tainted
[ 1137.127013] -------------------------------------------------------
[ 1137.127013] mdadm/16675 is trying to acquire lock:
[ 1137.127013]  (&bdev->bd_mutex){+.+.+.}, at: [<ffffffff81243cf3>] __blkdev_get+0x63/0x450
[ 1137.127013]
but task is already holding lock:
[ 1137.127013]  (detected_devices_mutex){+.+.+.}, at: [<ffffffff81a5138c>] md_ioctl+0x2ac/0x1f50
[ 1137.127013]
which lock already depends on the new lock.

[ 1137.127013]
the existing dependency chain (in reverse order) is:
[ 1137.127013]
-> #1 (detected_devices_mutex){+.+.+.}:
[ 1137.127013]        [<ffffffff810b6f19>] lock_acquire+0xb9/0x220
[ 1137.127013]        [<ffffffff81c51647>] mutex_lock_nested+0x67/0x3d0
[ 1137.127013]        [<ffffffff81a4eeaf>] md_autodetect_dev+0x3f/0x90
[ 1137.127013]        [<ffffffff81595be8>] rescan_partitions+0x1a8/0x2c0
[ 1137.127013]        [<ffffffff81590081>] __blkdev_reread_part+0x71/0xb0
[ 1137.127013]        [<ffffffff815900e5>] blkdev_reread_part+0x25/0x40
[ 1137.127013]        [<ffffffff81590c4b>] blkdev_ioctl+0x51b/0xa30
[ 1137.127013]        [<ffffffff81242bf1>] block_ioctl+0x41/0x50
[ 1137.127013]        [<ffffffff81214c96>] do_vfs_ioctl+0x96/0x6e0
[ 1137.127013]        [<ffffffff81215321>] SyS_ioctl+0x41/0x70
[ 1137.127013]        [<ffffffff81c56825>] entry_SYSCALL_64_fastpath+0x18/0xa8
[ 1137.127013]
-> #0 (&bdev->bd_mutex){+.+.+.}:
[ 1137.127013]        [<ffffffff810b6af2>] __lock_acquire+0x1662/0x1690
[ 1137.127013]        [<ffffffff810b6f19>] lock_acquire+0xb9/0x220
[ 1137.127013]        [<ffffffff81c51647>] mutex_lock_nested+0x67/0x3d0
[ 1137.127013]        [<ffffffff81243cf3>] __blkdev_get+0x63/0x450
[ 1137.127013]        [<ffffffff81244307>] blkdev_get+0x227/0x350
[ 1137.127013]        [<ffffffff812444f6>] blkdev_get_by_dev+0x36/0x50
[ 1137.127013]        [<ffffffff81a46d65>] lock_rdev+0x35/0x80
[ 1137.127013]        [<ffffffff81a49bb4>] md_import_device+0xb4/0x1b0
[ 1137.127013]        [<ffffffff81a513d6>] md_ioctl+0x2f6/0x1f50
[ 1137.127013]        [<ffffffff815909b3>] blkdev_ioctl+0x283/0xa30
[ 1137.127013]        [<ffffffff81242bf1>] block_ioctl+0x41/0x50
[ 1137.127013]        [<ffffffff81214c96>] do_vfs_ioctl+0x96/0x6e0
[ 1137.127013]        [<ffffffff81215321>] SyS_ioctl+0x41/0x70
[ 1137.127013]        [<ffffffff81c56825>] entry_SYSCALL_64_fastpath+0x18/0xa8
[ 1137.127013]
other info that might help us debug this:

[ 1137.127013]  Possible unsafe locking scenario:

[ 1137.127013]        CPU0                    CPU1
[ 1137.127013]        ----                    ----
[ 1137.127013]   lock(detected_devices_mutex);
[ 1137.127013]                                lock(&bdev->bd_mutex);
[ 1137.127013]                                lock(detected_devices_mutex);
[ 1137.127013]   lock(&bdev->bd_mutex);
[ 1137.127013]
 *** DEADLOCK ***

Cc: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: NShaohua Li <shli@fb.com>

cluster_info and bitmap_info.nodes also need to be
cleared when array is stopped.
Reviewed-by: NNeilBrown <neilb@suse.com>
Signed-off-by: NGuoqing Jiang <gqjiang@suse.com>
Signed-off-by: NShaohua Li <shli@fb.com>

When stop clustered raid while it is pending on resync,
MD_STILL_CLOSED flag could be cleared since udev rule
is triggered to open the mddev. So obviously array can't
be stopped soon and returns EBUSY.

	mdadm -Ss          md-raid-arrays.rules
  set MD_STILL_CLOSED          md_open()
	... ... ...          clear MD_STILL_CLOSED
	do_md_stop

We make below changes to resolve this issue:

1. rename MD_STILL_CLOSED to MD_CLOSING since it is set
   when stop array and it means we are stopping array.
2. let md_open returns early if CLOSING is set, so no
   other threads will open array if one thread is trying
   to close it.
3. no need to clear CLOSING bit in md_open because 1 has
   ensure the bit is cleared, then we also don't need to
   test CLOSING bit in do_md_stop.
Reviewed-by: NNeilBrown <neilb@suse.com>
Signed-off-by: NGuoqing Jiang <gqjiang@suse.com>
Signed-off-by: NShaohua Li <shli@fb.com>

The new_disk_ack could return failure if WAITING_FOR_NEWDISK
is not set, so we need to kick the dev from array in case
failure happened.

And we missed to check err before call new_disk_ack othwise
we could kick a rdev which isn't in array, thanks for the
reminder from Shaohua.
Reviewed-by: NNeilBrown <neilb@suse.com>
Signed-off-by: NGuoqing Jiang <gqjiang@suse.com>
Signed-off-by: NShaohua Li <shli@fb.com>

The md-cluster is compiled as module by default,
if it is compiled by built-in way, then we can't
make md-cluster works.

[64782.630008] md/raid1:md127: active with 2 out of 2 mirrors
[64782.630528] md-cluster module not found.
[64782.630530] md127: Could not setup cluster service (-2)

Fixes: edb39c9d ("Introduce md_cluster_operations to handle cluster functions")
Cc: stable@vger.kernel.org (v4.1+)
Reported-by: NMarc Smith <marc.smith@mcc.edu>
Reviewed-by: NNeilBrown <neilb@suse.com>
Signed-off-by: NGuoqing Jiang <gqjiang@suse.com>
Signed-off-by: NShaohua Li <shli@fb.com>

Currently, the code sets MD_JOURNAL_CLEAN when the array has
MD_FEATURE_JOURNAL and the recovery_cp is MaxSector. The array
will be MD_JOURNAL_CLEAN even if the journal device is missing.

With this patch, the MD_JOURNAL_CLEAN is only set when the journal
device presents.
Signed-off-by: NSong Liu <songliubraving@fb.com>
Signed-off-by: NShaohua Li <shli@fb.com>

This fixes a long-standing bug that caused a flood of messages like:
"md: delaying data-check of md1 until md2 has finished (they share one
or more physical units)"

It can be reproduced like this:
1. Create at least 3 raid1 arrays on a pair of disks, each on different
   partitions.
2. Request a sync operation like 'check' or 'repair' on 2 arrays by
   writing to their md/sync_action attribute files. One operation should
   start and one should be delayed and a message like the above will be
   printed.
3. Issue a write to the third array. Each write will cause 2 copies of
   the message to be printed.

This happens when wake_up(&resync_wait) is called, usually by
md_check_recovery(). Then the delayed sync thread again prints the
message and is put to sleep. This patch adds a check in md_do_sync() to
prevent printing this message more than once for the same pair of
devices.
Reported-by: NSven Koehler <sven.koehler@gmail.com>
Link: https://bugzilla.kernel.org/show_bug.cgi?id=151801Signed-off-by: NArtur Paszkiewicz <artur.paszkiewicz@intel.com>
Signed-off-by: NShaohua Li <shli@fb.com>

The ret is not needed anymore since we have already
move resync_start into md_do_sync in commit 41a9a0dc.
Reviewed-by: NNeilBrown <neilb@suse.com>
Signed-off-by: NGuoqing Jiang <gqjiang@suse.com>
Signed-off-by: NShaohua Li <shli@fb.com>

GET_ARRAY_INFO counts journal as spare (spare_disks), which is not
accurate. This patch fixes this.
Reported-by: NYi Zhang <yizhan@redhat.com>
Signed-off-by: NSong Liu <songliubraving@fb.com>
Signed-off-by: NShaohua Li <shli@fb.com>

Since commit 63a4cc24, bio->bi_rw contains flags in the lower
portion and the op code in the higher portions. This means that
old code that relies on manually setting bi_rw is most likely
going to be broken. Instead of letting that brokeness linger,
rename the member, to force old and out-of-tree code to break
at compile time instead of at runtime.

No intended functional changes in this commit.
Signed-off-by: NJens Axboe <axboe@fb.com>

The md device might not have personality (for example, ddf raid array). The
issue is introduced by 8430e7e0(md: disconnect device from personality
before trying to remove it)
Reported-by: Nkernel test robot <xiaolong.ye@intel.com>
Signed-off-by: NShaohua Li <shli@fb.com>

Changeset 6791875e has added early return from a function so there is no
sysfs notification for 'active' and 'clean' state change.
Signed-off-by: NTomasz Majchrzak <tomasz.majchrzak@intel.com>
Signed-off-by: NShaohua Li <shli@fb.com>

md loads raidX modules and increments module refcount each time level
has changed but does not decrement it. You are unable to unload raid0
module after reshape because raid0 reshape changes level to raid4
and back to raid0.
Signed-off-by: NAleksey Obitotskiy <aleksey.obitotskiy@intel.com>
Signed-off-by: NShaohua Li <shli@fb.com>

The md code stores the exact time of the last error in the
last_read_error variable using a timespec structure. It only
ever uses the seconds portion of that though, so we can
use a scalar for it.

There won't be an overflow in 2038 here, because it already
used monotonic time and 32-bit is enough for that, but I've
decided to use time64_t for consistency in the conversion.
Signed-off-by: NArnd Bergmann <arnd@arndb.de>
Signed-off-by: NShaohua Li <shli@fb.com>

Every time a device is removed with ->hot_remove_disk() a synchronize_rcu() call is made
which can delay several milliseconds in some case.
If lots of devices fail at once - as could happen with a large RAID10 where one set
of devices are removed all at once - these delays can add up to be very inconcenient.

As failure is not reversible we can check for that first, setting a
separate flag if it is found, and then all synchronize_rcu() once for
all the flagged devices.  Then ->hot_remove_disk() function can skip the
synchronize_rcu() step if the flag is set.

fix build error(Shaohua)
Signed-off-by: NNeilBrown <neilb@suse.com>
Signed-off-by: NShaohua Li <shli@fb.com>

When the HOT_REMOVE_DISK ioctl is used to remove a device, we
call remove_and_add_spares() which will remove it from the personality
if possible.  This improves the chances that the removal will succeed.

When writing "remove" to dev-XX/state, we don't.  So that can fail more easily.

So add the remove_and_add_spares() into "remove" handling.
Signed-off-by: NNeilBrown <neilb@suse.com>
Signed-off-by: NShaohua Li <shli@fb.com>

This is a simple check before updating the superblock. It should update
the superblock when update_size return 0.
Signed-off-by: NXiao Ni <xni@redhat.com>
Signed-off-by: NShaohua Li <shli@fb.com>

We saw a list corruption in the list all_detected_devices:

 WARNING: CPU: 16 PID: 226 at lib/list_debug.c:29 __list_add+0x3c/0xa9()
 list_add corruption. next->prev should be prev (ffff880859d58320), but was ffff880859ce74c0. (next=ffffffff81abfdb0).
 Modules linked in: ahci libahci libata sd_mod scsi_mod
 CPU: 16 PID: 226 Comm: kworker/u241:4 Not tainted 4.1.20 #1
 Hardware name: Dell Inc. PowerEdge C6220/04GD66, BIOS 2.2.3 11/07/2013
 Workqueue: events_unbound async_run_entry_fn
  0000000000000000 ffff880859a5baf8 ffffffff81502872 ffff880859a5bb48
  0000000000000009 ffff880859a5bb38 ffffffff810692a5 ffff880859ee8828
  ffffffff812ad02c ffff880859d58320 ffffffff81abfdb0 ffff880859eb90c0
 Call Trace:
  [<ffffffff81502872>] dump_stack+0x4d/0x63
  [<ffffffff810692a5>] warn_slowpath_common+0xa1/0xbb
  [<ffffffff812ad02c>] ? __list_add+0x3c/0xa9
  [<ffffffff81069305>] warn_slowpath_fmt+0x46/0x48
  [<ffffffff812ad02c>] __list_add+0x3c/0xa9
  [<ffffffff81406f28>] md_autodetect_dev+0x41/0x62
  [<ffffffff81285862>] rescan_partitions+0x25f/0x29d
  [<ffffffff81506372>] ? mutex_lock+0x13/0x31
  [<ffffffff811a090f>] __blkdev_get+0x1aa/0x3cd
  [<ffffffff811a0b91>] blkdev_get+0x5f/0x294
  [<ffffffff81377ceb>] ? put_device+0x17/0x19
  [<ffffffff8128227c>] ? disk_put_part+0x12/0x14
  [<ffffffff812836f3>] add_disk+0x29d/0x407
  [<ffffffff81384345>] ? __pm_runtime_use_autosuspend+0x5c/0x64
  [<ffffffffa004a724>] sd_probe_async+0x115/0x1af [sd_mod]
  [<ffffffff81083177>] async_run_entry_fn+0x72/0x12c
  [<ffffffff8107c44c>] process_one_work+0x198/0x2ce
  [<ffffffff8107cac7>] worker_thread+0x1dd/0x2bb
  [<ffffffff8107c8ea>] ? cancel_delayed_work_sync+0x15/0x15
  [<ffffffff8107c8ea>] ? cancel_delayed_work_sync+0x15/0x15
  [<ffffffff81080d9c>] kthread+0xae/0xb6
  [<ffffffff81080000>] ? param_array_set+0x40/0xfa
  [<ffffffff81080cee>] ? __kthread_parkme+0x61/0x61
  [<ffffffff81508152>] ret_from_fork+0x42/0x70
  [<ffffffff81080cee>] ? __kthread_parkme+0x61/0x61

I suspect it is because there is no lock protecting this
global list, autostart_arrays() is called in ioctl() path
where there is no lock.

Cc: Shaohua Li <shli@kernel.org>
Signed-off-by: NCong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: NShaohua Li <shli@fb.com>

To avoid confusion between REQ_OP_FLUSH, which is handled by
request_fn drivers, and upper layers requesting the block layer
perform a flush sequence along with possibly a WRITE, this patch
renames REQ_FLUSH to REQ_PREFLUSH.
Signed-off-by: NMike Christie <mchristi@redhat.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NHannes Reinecke <hare@suse.com>
Signed-off-by: NJens Axboe <axboe@fb.com>

Separate the op from the rq_flag_bits and have md
set/get the bio using bio_set_op_attrs/bio_op.
Signed-off-by: NMike Christie <mchristi@redhat.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NHannes Reinecke <hare@suse.com>
Signed-off-by: NJens Axboe <axboe@fb.com>

This has callers of submit_bio/submit_bio_wait set the bio->bi_rw
instead of passing it in. This makes that use the same as
generic_make_request and how we set the other bio fields.
Signed-off-by: NMike Christie <mchristi@redhat.com>

Fixed up fs/ext4/crypto.c
Signed-off-by: NJens Axboe <axboe@fb.com>

Signed-off-by: NGuoqing Jiang <gqjiang@suse.com>
Signed-off-by: NShaohua Li <shli@fb.com>

Add a disk to an array which is performing recovery
is a little complicated, we need to do both reap the
sync thread and perform add disk for the case, then
it caused deadlock as follows.

linux44:~ # ps aux|grep md|grep D
root      1822  0.0  0.0      0     0 ?        D    16:50   0:00 [md127_resync]
root      1848  0.0  0.0  19860   952 pts/0    D+   16:50   0:00 mdadm --manage /dev/md127 --re-add /dev/vdb
linux44:~ # cat /proc/1848/stack
[<ffffffff8107afde>] kthread_stop+0x6e/0x120
[<ffffffffa051ddb0>] md_unregister_thread+0x40/0x80 [md_mod]
[<ffffffffa0526e45>] md_reap_sync_thread+0x15/0x150 [md_mod]
[<ffffffffa05271e0>] action_store+0x260/0x270 [md_mod]
[<ffffffffa05206b4>] md_attr_store+0xb4/0x100 [md_mod]
[<ffffffff81214a7e>] sysfs_write_file+0xbe/0x140
[<ffffffff811a6b98>] vfs_write+0xb8/0x1e0
[<ffffffff811a75b8>] SyS_write+0x48/0xa0
[<ffffffff8152a5c9>] system_call_fastpath+0x16/0x1b
[<00007f068ea1ed30>] 0x7f068ea1ed30
linux44:~ # cat /proc/1822/stack
[<ffffffffa05251a6>] md_do_sync+0x846/0xf40 [md_mod]
[<ffffffffa052402d>] md_thread+0x16d/0x180 [md_mod]
[<ffffffff8107ad94>] kthread+0xb4/0xc0
[<ffffffff8152a518>] ret_from_fork+0x58/0x90

                        Task1848                                Task1822
md_attr_store (held reconfig_mutex by call mddev_lock())
                        action_store
			md_reap_sync_thread
			md_unregister_thread
			kthread_stop                    md_wakeup_thread(mddev->thread);
						wait_event(mddev->sb_wait, !test_bit(MD_CHANGE_PENDING))

md_check_recovery is triggered by wakeup mddev->thread,
but it can't clear MD_CHANGE_PENDING flag since it can't
get lock which was held by md_attr_store already.

To solve the deadlock problem, we move "->resync_finish()"
from md_do_sync to md_reap_sync_thread (after md_update_sb),
also MD_HELD_RESYNC_LOCK is introduced since it is possible
that node can't get resync lock in md_do_sync.

Then we do not need to wait for MD_CHANGE_PENDING is cleared
or not since metadata should be updated after md_update_sb,
so just call resync_finish if MD_HELD_RESYNC_LOCK is set.

We also unified the code after skip label, since set PENDING
for non-clustered case should be harmless.
Reviewed-by: NNeilBrown <neilb@suse.com>
Signed-off-by: NGuoqing Jiang <gqjiang@suse.com>
Signed-off-by: NShaohua Li <shli@fb.com>

Some code waits for a metadata update by:

1. flagging that it is needed (MD_CHANGE_DEVS or MD_CHANGE_CLEAN)
2. setting MD_CHANGE_PENDING and waking the management thread
3. waiting for MD_CHANGE_PENDING to be cleared

If the first two are done without locking, the code in md_update_sb()
which checks if it needs to repeat might test if an update is needed
before step 1, then clear MD_CHANGE_PENDING after step 2, resulting
in the wait returning early.

So make sure all places that set MD_CHANGE_PENDING are atomicial, and
bit_clear_unless (suggested by Neil) is introduced for the purpose.

Cc: Martin Kepplinger <martink@posteo.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Sasha Levin <sasha.levin@oracle.com>
Cc: <linux-kernel@vger.kernel.org>
Reviewed-by: NNeilBrown <neilb@suse.com>
Signed-off-by: NGuoqing Jiang <gqjiang@suse.com>
Signed-off-by: NShaohua Li <shli@fb.com>

Introduced by upstream commit 70d9798b

The raid0 personality does not create mddev->thread as oposed to
other personalities leading to its unconditional access in
mddev_suspend() causing an oops.

Patch checks for mddev->thread in order to keep the
intention of aforementioned commit.

Fixes: 70d9798b ("MD: warn for potential deadlock")
Cc: stable@vger.kernel.org (4.5+)
Signed-off-by: NHeinz Mauelshagen <heinzm@redhat.com>
Signed-off-by: NShaohua Li <shli@fb.com>

When a device is re-added, it will ultimately need
to be activated and that happens in md_check_recovery,
so we need to set MD_RECOVERY_NEEDED right after
remove_and_add_spares.

A specifical issue without the change is that when
one node perform fail/remove/readd on a disk, but
slave nodes could not add the disk back to array as
expected (added as missed instead of in sync). So
give slave nodes a chance to do resync.
Reviewed-by: NNeilBrown <neilb@suse.com>
Signed-off-by: NGuoqing Jiang <gqjiang@suse.com>
Signed-off-by: NShaohua Li <shli@fb.com>

Currently, some features are not supported yet,
such as change array_sectors and update size, so
return EINVAL for them and listed it in document.
Reviewed-by: NNeilBrown <neilb@suse.com>
Signed-off-by: NGuoqing Jiang <gqjiang@suse.com>
Signed-off-by: NShaohua Li <shli@fb.com>

It is not reasonable that cluster raid to release resync
lock before the last pers->sync_request has finished.

As the metadata will be changed when node performs resync,
we need to inform other nodes to update metadata, so the
MD_CHANGE_PENDING flag is set before finish resync.

Then metadata_update_finish is move ahead to ensure that
METADATA_UPDATED msg is sent before finish resync, and
metadata_update_start need to be run after "repeat:" label
accordingly.
Reviewed-by: NNeilBrown <neilb@suse.com>
Signed-off-by: NGuoqing Jiang <gqjiang@suse.com>
Signed-off-by: NShaohua Li <shli@fb.com>

If multiple nodes choose to attempt do resync at the same time
they need to be serialized so they don't duplicate effort. This
serialization is done by locking the 'resync' DLM lock.

Currently if a node cannot get the lock immediately it doesn't
request notification when the lock becomes available (i.e.
DLM_LKF_NOQUEUE is set), so it may not reliably find out when it
is safe to try again.

Rather than trying to arrange an async wake-up when the lock
becomes available, switch to using synchronous locking - this is
a lot easier to think about.  As it is not permitted to block in
the 'raid1d' thread, move the locking to the resync thread.  So
the rsync thread is forked immediately, but it blocks until the
resync lock is available. Once the lock is locked it checks again
if any resync action is needed.

A particular symptom of the current problem is that a node can
get stuck with "resync=pending" indefinitely.
Reviewed-by: NNeilBrown <neilb@suse.com>
Signed-off-by: NGuoqing Jiang <gqjiang@suse.com>
Signed-off-by: NShaohua Li <shli@fb.com>

blk_queue_split marks bio unmergeable, which makes sense for normal bio.
But if dispatching the bio to underlayer disk, the blk_queue_split
checks are invalid, hence it's possible the bio becomes mergeable.

In the reported bug, this bug causes trim against raid0 performance slash
https://bugzilla.kernel.org/show_bug.cgi?id=117051Reported-and-tested-by: NPark Ju Hyung <qkrwngud825@gmail.com>
Fixes: 6ac45aeb(block: avoid to merge splitted bio)
Cc: stable@vger.kernel.org (v4.3+)
Cc: Ming Lei <ming.lei@canonical.com>
Cc: Neil Brown <neilb@suse.de>
Reviewed-by: NJens Axboe <axboe@fb.com>
Signed-off-by: NShaohua Li <shli@fb.com>