md: remove the extra line for ->hot_add_disk

It is not not necessary to add a newline for them since they don't exceed
80 characters, and it is not intutive to distinguish ->hot_add_disk() from
hot_

md: remove the extra line for ->hot_add_disk

It is not not necessary to add a newline for them since they don't exceed
80 characters, and it is not intutive to distinguish ->hot_add_disk() from
hot_add_disk() too.

Signed-off-by: Guoqing Jiang <guoqing.jiang@cloud.ionos.com>
Signed-off-by: Song Liu <songliubraving@fb.com>

show more ...

md: flush md_rdev_misc_wq for HOT_ADD_DISK case

Since rdev->kobj is removed asynchronously, it is possible that the
rdev->kobj still exists when try to add the rdev again after rdev
is removed. But

md: flush md_rdev_misc_wq for HOT_ADD_DISK case

Since rdev->kobj is removed asynchronously, it is possible that the
rdev->kobj still exists when try to add the rdev again after rdev
is removed. But this path md_ioctl (HOT_ADD_DISK) -> hot_add_disk
-> bind_rdev_to_array missed it.

Signed-off-by: Guoqing Jiang <guoqing.jiang@cloud.ionos.com>
Signed-off-by: Song Liu <songliubraving@fb.com>

show more ...

md: don't flush workqueue unconditionally in md_open

We need to check mddev->del_work before flush workqueu since the purpose
of flush is to ensure the previous md is disappeared. Otherwise the simi

md: don't flush workqueue unconditionally in md_open

We need to check mddev->del_work before flush workqueu since the purpose
of flush is to ensure the previous md is disappeared. Otherwise the similar
deadlock appeared if LOCKDEP is enabled, it is due to md_open holds the
bdev->bd_mutex before flush workqueue.

kernel: [ 154.522645] ======================================================
kernel: [ 154.522647] WARNING: possible circular locking dependency detected
kernel: [ 154.522650] 5.6.0-rc7-lp151.27-default #25 Tainted: G O
kernel: [ 154.522651] ------------------------------------------------------
kernel: [ 154.522653] mdadm/2482 is trying to acquire lock:
kernel: [ 154.522655] ffff888078529128 ((wq_completion)md_misc){+.+.}, at: flush_workqueue+0x84/0x4b0
kernel: [ 154.522673]
kernel: [ 154.522673] but task is already holding lock:
kernel: [ 154.522675] ffff88804efa9338 (&bdev->bd_mutex){+.+.}, at: __blkdev_get+0x79/0x590
kernel: [ 154.522691]
kernel: [ 154.522691] which lock already depends on the new lock.
kernel: [ 154.522691]
kernel: [ 154.522694]
kernel: [ 154.522694] the existing dependency chain (in reverse order) is:
kernel: [ 154.522696]
kernel: [ 154.522696] -> #4 (&bdev->bd_mutex){+.+.}:
kernel: [ 154.522704] __mutex_lock+0x87/0x950
kernel: [ 154.522706] __blkdev_get+0x79/0x590
kernel: [ 154.522708] blkdev_get+0x65/0x140
kernel: [ 154.522709] blkdev_get_by_dev+0x2f/0x40
kernel: [ 154.522716] lock_rdev+0x3d/0x90 [md_mod]
kernel: [ 154.522719] md_import_device+0xd6/0x1b0 [md_mod]
kernel: [ 154.522723] new_dev_store+0x15e/0x210 [md_mod]
kernel: [ 154.522728] md_attr_store+0x7a/0xc0 [md_mod]
kernel: [ 154.522732] kernfs_fop_write+0x117/0x1b0
kernel: [ 154.522735] vfs_write+0xad/0x1a0
kernel: [ 154.522737] ksys_write+0xa4/0xe0
kernel: [ 154.522745] do_syscall_64+0x64/0x2b0
kernel: [ 154.522748] entry_SYSCALL_64_after_hwframe+0x49/0xbe
kernel: [ 154.522749]
kernel: [ 154.522749] -> #3 (&mddev->reconfig_mutex){+.+.}:
kernel: [ 154.522752] __mutex_lock+0x87/0x950
kernel: [ 154.522756] new_dev_store+0xc9/0x210 [md_mod]
kernel: [ 154.522759] md_attr_store+0x7a/0xc0 [md_mod]
kernel: [ 154.522761] kernfs_fop_write+0x117/0x1b0
kernel: [ 154.522763] vfs_write+0xad/0x1a0
kernel: [ 154.522765] ksys_write+0xa4/0xe0
kernel: [ 154.522767] do_syscall_64+0x64/0x2b0
kernel: [ 154.522769] entry_SYSCALL_64_after_hwframe+0x49/0xbe
kernel: [ 154.522770]
kernel: [ 154.522770] -> #2 (kn->count#253){++++}:
kernel: [ 154.522775] __kernfs_remove+0x253/0x2c0
kernel: [ 154.522778] kernfs_remove+0x1f/0x30
kernel: [ 154.522780] kobject_del+0x28/0x60
kernel: [ 154.522783] mddev_delayed_delete+0x24/0x30 [md_mod]
kernel: [ 154.522786] process_one_work+0x2a7/0x5f0
kernel: [ 154.522788] worker_thread+0x2d/0x3d0
kernel: [ 154.522793] kthread+0x117/0x130
kernel: [ 154.522795] ret_from_fork+0x3a/0x50
kernel: [ 154.522796]
kernel: [ 154.522796] -> #1 ((work_completion)(&mddev->del_work)){+.+.}:
kernel: [ 154.522800] process_one_work+0x27e/0x5f0
kernel: [ 154.522802] worker_thread+0x2d/0x3d0
kernel: [ 154.522804] kthread+0x117/0x130
kernel: [ 154.522806] ret_from_fork+0x3a/0x50
kernel: [ 154.522807]
kernel: [ 154.522807] -> #0 ((wq_completion)md_misc){+.+.}:
kernel: [ 154.522813] __lock_acquire+0x1392/0x1690
kernel: [ 154.522816] lock_acquire+0xb4/0x1a0
kernel: [ 154.522818] flush_workqueue+0xab/0x4b0
kernel: [ 154.522821] md_open+0xb6/0xc0 [md_mod]
kernel: [ 154.522823] __blkdev_get+0xea/0x590
kernel: [ 154.522825] blkdev_get+0x65/0x140
kernel: [ 154.522828] do_dentry_open+0x1d1/0x380
kernel: [ 154.522831] path_openat+0x567/0xcc0
kernel: [ 154.522834] do_filp_open+0x9b/0x110
kernel: [ 154.522836] do_sys_openat2+0x201/0x2a0
kernel: [ 154.522838] do_sys_open+0x57/0x80
kernel: [ 154.522840] do_syscall_64+0x64/0x2b0
kernel: [ 154.522842] entry_SYSCALL_64_after_hwframe+0x49/0xbe
kernel: [ 154.522844]
kernel: [ 154.522844] other info that might help us debug this:
kernel: [ 154.522844]
kernel: [ 154.522846] Chain exists of:
kernel: [ 154.522846] (wq_completion)md_misc --> &mddev->reconfig_mutex --> &bdev->bd_mutex
kernel: [ 154.522846]
kernel: [ 154.522850] Possible unsafe locking scenario:
kernel: [ 154.522850]
kernel: [ 154.522852] CPU0 CPU1
kernel: [ 154.522853] ---- ----
kernel: [ 154.522854] lock(&bdev->bd_mutex);
kernel: [ 154.522856] lock(&mddev->reconfig_mutex);
kernel: [ 154.522858] lock(&bdev->bd_mutex);
kernel: [ 154.522860] lock((wq_completion)md_misc);
kernel: [ 154.522861]
kernel: [ 154.522861] *** DEADLOCK ***
kernel: [ 154.522861]
kernel: [ 154.522864] 1 lock held by mdadm/2482:
kernel: [ 154.522865] #0: ffff88804efa9338 (&bdev->bd_mutex){+.+.}, at: __blkdev_get+0x79/0x590
kernel: [ 154.522868]
kernel: [ 154.522868] stack backtrace:
kernel: [ 154.522873] CPU: 1 PID: 2482 Comm: mdadm Tainted: G O 5.6.0-rc7-lp151.27-default #25
kernel: [ 154.522875] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1ubuntu1 04/01/2014
kernel: [ 154.522878] Call Trace:
kernel: [ 154.522881] dump_stack+0x8f/0xcb
kernel: [ 154.522884] check_noncircular+0x194/0x1b0
kernel: [ 154.522888] ? __lock_acquire+0x1392/0x1690
kernel: [ 154.522890] __lock_acquire+0x1392/0x1690
kernel: [ 154.522893] lock_acquire+0xb4/0x1a0
kernel: [ 154.522895] ? flush_workqueue+0x84/0x4b0
kernel: [ 154.522898] flush_workqueue+0xab/0x4b0
kernel: [ 154.522900] ? flush_workqueue+0x84/0x4b0
kernel: [ 154.522905] ? md_open+0xb6/0xc0 [md_mod]
kernel: [ 154.522908] md_open+0xb6/0xc0 [md_mod]
kernel: [ 154.522910] __blkdev_get+0xea/0x590
kernel: [ 154.522912] ? bd_acquire+0xc0/0xc0
kernel: [ 154.522914] blkdev_get+0x65/0x140
kernel: [ 154.522916] ? bd_acquire+0xc0/0xc0
kernel: [ 154.522918] do_dentry_open+0x1d1/0x380
kernel: [ 154.522921] path_openat+0x567/0xcc0
kernel: [ 154.522923] ? __lock_acquire+0x380/0x1690
kernel: [ 154.522926] do_filp_open+0x9b/0x110
kernel: [ 154.522929] ? __alloc_fd+0xe5/0x1f0
kernel: [ 154.522935] ? kmem_cache_alloc+0x28c/0x630
kernel: [ 154.522939] ? do_sys_openat2+0x201/0x2a0
kernel: [ 154.522941] do_sys_openat2+0x201/0x2a0
kernel: [ 154.522944] do_sys_open+0x57/0x80
kernel: [ 154.522946] do_syscall_64+0x64/0x2b0
kernel: [ 154.522948] entry_SYSCALL_64_after_hwframe+0x49/0xbe
kernel: [ 154.522951] RIP: 0033:0x7f98d279d9ae

And md_alloc also flushed the same workqueue, but the thing is different
here. Because all the paths call md_alloc don't hold bdev->bd_mutex, and
the flush is necessary to avoid race condition, so leave it as it is.

Signed-off-by: Guoqing Jiang <guoqing.jiang@cloud.ionos.com>
Signed-off-by: Song Liu <songliubraving@fb.com>

show more ...

md: add new workqueue for delete rdev

Since the purpose of call flush_workqueue in new_dev_store is to ensure
md_delayed_delete() has completed, so we should check rdev->del_work is
pending or not.

md: add new workqueue for delete rdev

Since the purpose of call flush_workqueue in new_dev_store is to ensure
md_delayed_delete() has completed, so we should check rdev->del_work is
pending or not.

To suppress lockdep warning, we have to check mddev->del_work while
md_delayed_delete is attached to rdev->del_work, so it is not aligned
to the purpose of flush workquee. So a new workqueue is needed to avoid
the awkward situation, and introduce a new func flush_rdev_wq to flush
the new workqueue after check if there was pending work.

Also like new_dev_store, ADD_NEW_DISK ioctl has the same purpose to flush
workqueue while it holds bdev->bd_mutex, so make the same change applies
to the ioctl to avoid similar lock issue.

And md_delayed_delete actually wants to delete rdev, so rename the function
to rdev_delayed_delete.

Signed-off-by: Guoqing Jiang <guoqing.jiang@cloud.ionos.com>
Signed-off-by: Song Liu <songliubraving@fb.com>

show more ...

md: add checkings before flush md_misc_wq

Coly reported possible circular locking dependencyi with LOCKDEP enabled,
quote the below info from the detailed report [1].

[ 1607.673903] Chain exists of

md: add checkings before flush md_misc_wq

Coly reported possible circular locking dependencyi with LOCKDEP enabled,
quote the below info from the detailed report [1].

[ 1607.673903] Chain exists of:
[ 1607.673903] kn->count#256 --> (wq_completion)md_misc -->
(work_completion)(&rdev->del_work)
[ 1607.673903]
[ 1607.827946] Possible unsafe locking scenario:
[ 1607.827946]
[ 1607.898780] CPU0 CPU1
[ 1607.952980] ---- ----
[ 1608.007173] lock((work_completion)(&rdev->del_work));
[ 1608.069690] lock((wq_completion)md_misc);
[ 1608.149887] lock((work_completion)(&rdev->del_work));
[ 1608.242563] lock(kn->count#256);
[ 1608.283238]
[ 1608.283238] *** DEADLOCK ***
[ 1608.283238]
[ 1608.354078] 2 locks held by kworker/5:0/843:
[ 1608.405152] #0: ffff8889eecc9948 ((wq_completion)md_misc){+.+.}, at:
process_one_work+0x42b/0xb30
[ 1608.512399] #1: ffff888a1d3b7e10
((work_completion)(&rdev->del_work)){+.+.}, at: process_one_work+0x42b/0xb30
[ 1608.632130]

Since works (rdev->del_work and mddev->del_work) are queued in md_misc_wq,
then lockdep_map lock is held if either of them are running, then both of
them try to hold kernfs lock by call kobject_del. Then if new_dev_store
or array_state_store are triggered by write to the related sysfs node, so
the write operation gets kernfs lock, but need the lockdep_map because all
of them would trigger flush_workqueue(md_misc_wq) finally, then the same
lockdep_map lock is needed.

To suppress the lockdep warnning, we should flush the workqueue in case the
related work is pending. And several works are attached to md_misc_wq, so
we need to check which work should be checked:

1. for __md_stop_writes, the purpose of call flush workqueue is ensure sync
thread is started if it was starting, so check mddev->del_work is pending
or not since md_start_sync is attached to mddev->del_work.

2. __md_stop flushes md_misc_wq to ensure event_work is done, check the
event_work is enough. Assume raid_{ctr,dtr} -> md_stop -> __md_stop doesn't
need the kernfs lock.

3. both new_dev_store (holds kernfs lock) and ADD_NEW_DISK ioctl (holds the
bdev->bd_mutex) call flush_workqueue to ensure md_delayed_delete has
completed, this case will be handled in next patch.

4. md_open flushes workqueue to ensure the previous md is disappeared, but
it holds bdev->bd_mutex then try to flush workqueue, so it is better to
check mddev->del_work as well to avoid potential lock issue, this will be
done in another patch.

[1]: https://marc.info/?l=linux-raid&m=158518958031584&w=2

Cc: Coly Li <colyli@suse.de>
Reported-by: Coly Li <colyli@suse.de>
Signed-off-by: Guoqing Jiang <guoqing.jiang@cloud.ionos.com>
Signed-off-by: Song Liu <songliubraving@fb.com>

show more ...

block: simplify queue allocation

Current make_request based drivers use either blk_alloc_queue_node or
blk_alloc_queue to allocate a queue, and then set up the make_request_fn
function pointer and a

block: simplify queue allocation

Current make_request based drivers use either blk_alloc_queue_node or
blk_alloc_queue to allocate a queue, and then set up the make_request_fn
function pointer and a few parameters using the blk_queue_make_request
helper. Simplify this by passing the make_request pointer to
blk_alloc_queue, and while at it merge the _node variant into the main
helper by always passing a node_id, and remove the superfluous gfp_mask
parameter. A lower-level __blk_alloc_queue is kept for the blk-mq case.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

show more ...

block: move the part_stat* helpers from genhd.h to a new header

These macros are just used by a few files. Move them out of genhd.h,
which is included everywhere into a new standalone header.

Sign

block: move the part_stat* helpers from genhd.h to a new header

These macros are just used by a few files. Move them out of genhd.h,
which is included everywhere into a new standalone header.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

show more ...

block: cleanup how md_autodetect_dev is called

Add a new include/linux/raid/detect.h header to declare the
md_autodetect_dev prototype which can be shared between md and
the partition code. Then us

block: cleanup how md_autodetect_dev is called

Add a new include/linux/raid/detect.h header to declare the
md_autodetect_dev prototype which can be shared between md and
the partition code. Then use IS_BUILTIN to call it instead of the
ifdef magic.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

show more ...

block: remove __bdevname

There is no good reason for __bdevname to exist. Just open code
printing the string in the callers. For three of them the format
string can be trivially merged into existi

block: remove __bdevname

There is no good reason for __bdevname to exist. Just open code
printing the string in the callers. For three of them the format
string can be trivially merged into existing printk statements,
and in init/do_mounts.c we can at least do the scnprintf once at
the start of the function, and unconditional of CONFIG_BLOCK to
make the output for tiny configfs a little more helpful.

Acked-by: Theodore Ts'o <tytso@mit.edu> # for ext4
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

show more ...

md: check arrays is suspended in mddev_detach before call quiesce operations

Don't call quiesce(1) and quiesce(0) if array is already suspended,
otherwise in level_store, the array is writable after

md: check arrays is suspended in mddev_detach before call quiesce operations

Don't call quiesce(1) and quiesce(0) if array is already suspended,
otherwise in level_store, the array is writable after mddev_detach
in below part though the intention is to make array writable after
resume.

mddev_suspend(mddev);
mddev_detach(mddev);
...
mddev_resume(mddev);

And it also causes calltrace as follows in [1].

[48005.653834] WARNING: CPU: 1 PID: 45380 at kernel/kthread.c:510 kthread_park+0x77/0x90
[...]
[48005.653976] CPU: 1 PID: 45380 Comm: mdadm Tainted: G OE 5.4.10-arch1-1 #1
[48005.653979] Hardware name: To Be Filled By O.E.M. To Be Filled By O.E.M./J4105-ITX, BIOS P1.40 08/06/2018
[48005.653984] RIP: 0010:kthread_park+0x77/0x90
[48005.654015] Call Trace:
[48005.654039] r5l_quiesce+0x3c/0x70 [raid456]
[48005.654052] raid5_quiesce+0x228/0x2e0 [raid456]
[48005.654073] mddev_detach+0x30/0x70 [md_mod]
[48005.654090] level_store+0x202/0x670 [md_mod]
[48005.654099] ? security_capable+0x40/0x60
[48005.654114] md_attr_store+0x7b/0xc0 [md_mod]
[48005.654123] kernfs_fop_write+0xce/0x1b0
[48005.654132] vfs_write+0xb6/0x1a0
[48005.654138] ksys_write+0x67/0xe0
[48005.654146] do_syscall_64+0x4e/0x140
[48005.654155] entry_SYSCALL_64_after_hwframe+0x44/0xa9
[48005.654161] RIP: 0033:0x7fa0c8737497

[1]: https://bugzilla.kernel.org/show_bug.cgi?id=206161

Signed-off-by: Guoqing Jiang <guoqing.jiang@cloud.ionos.com>
Signed-off-by: Song Liu <songliubraving@fb.com>

show more ...

proc: convert everything to "struct proc_ops"

The most notable change is DEFINE_SHOW_ATTRIBUTE macro split in
seq_file.h.

Conversion rule is:

llseek => proc_lseek
unlocked_ioctl => proc_ioctl

proc: convert everything to "struct proc_ops"

The most notable change is DEFINE_SHOW_ATTRIBUTE macro split in
seq_file.h.

Conversion rule is:

llseek => proc_lseek
unlocked_ioctl => proc_ioctl

xxx => proc_xxx

delete ".owner = THIS_MODULE" line

[akpm@linux-foundation.org: fix drivers/isdn/capi/kcapi_proc.c]
[sfr@canb.auug.org.au: fix kernel/sched/psi.c]
Link: http://lkml.kernel.org/r/20200122180545.36222f50@canb.auug.org.au
Link: http://lkml.kernel.org/r/20191225172546.GB13378@avx2
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

show more ...

md/raid1: use bucket based mechanism for IO serialization

Since raid1 had already used bucket based mechanism to reduce
the conflict between write IO and resync IO, it is possible to
speed up perfor

md/raid1: use bucket based mechanism for IO serialization

Since raid1 had already used bucket based mechanism to reduce
the conflict between write IO and resync IO, it is possible to
speed up performance for io serialization with refer to the
same mechanism.

To align with the barrier bucket mechanism, we created arrays
(with the same number of BARRIER_BUCKETS_NR) for spinlock, rb
tree and waitqueue. Then we can reduce lock competition with
multiple spinlocks, boost search performance with multiple rb
trees and also reduce thundering herd problem with multiple
waitqueues.

Signed-off-by: Guoqing Jiang <guoqing.jiang@cloud.ionos.com>
Signed-off-by: Song Liu <songliubraving@fb.com>

show more ...

md: introduce a new struct for IO serialization

Obviously, IO serialization could cause the degradation of
performance a lot. In order to reduce the degradation, so a
rb interval tree is added in ra

md: introduce a new struct for IO serialization

Obviously, IO serialization could cause the degradation of
performance a lot. In order to reduce the degradation, so a
rb interval tree is added in raid1 to speed up the check of
collision.

So, a rb root is needed in md_rdev, then abstract all the
serialize related members to a new struct (serial_in_rdev),
embed it into md_rdev.

Of course, we need to free the struct if it is not needed
anymore, so rdev/rdevs_uninit_serial are added accordingly.
And they should be called when destroty memory pool or can't
alloc memory.

And we need to consider to call mddev_destroy_serial_pool
in case serialize_policy/write-behind is disabled, bitmap
is destroyed or in __md_stop_writes.

Signed-off-by: Guoqing Jiang <guoqing.jiang@cloud.ionos.com>
Signed-off-by: Song Liu <songliubraving@fb.com>

show more ...

md: reorgnize mddev_create/destroy_serial_pool

So far, IO serialization is used for two scenarios:

1. raid1 which enables write-behind mode, and there is rdev in the array
which is multi-queue devi

md: reorgnize mddev_create/destroy_serial_pool

So far, IO serialization is used for two scenarios:

1. raid1 which enables write-behind mode, and there is rdev in the array
which is multi-queue device and flaged with writemostly.
2. IO serialization is enabled or disabled by change serialize_policy.

So introduce rdev_need_serial to check the first scenario. And for 1, IO
serialization is enabled automatically while 2 is controlled manually.

And it is possible that both scenarios are true, so for create serial pool,
rdev/rdevs_init_serial should be separate from check if the pool existed or
not. Then for destroy pool, we need to check if the pool is needed by other
rdevs due to the first scenario.

Signed-off-by: Guoqing Jiang <guoqing.jiang@cloud.ionos.com>
Signed-off-by: Song Liu <songliubraving@fb.com>

show more ...

md: add serialize_policy sysfs node for raid1

With the new sysfs node, we can use it to control if raid1 array
wants io serialization or not. So mddev_create_serial_pool and
mddev_destroy_serial_poo

md: add serialize_policy sysfs node for raid1

With the new sysfs node, we can use it to control if raid1 array
wants io serialization or not. So mddev_create_serial_pool and
mddev_destroy_serial_pool are called in serialize_policy_store
to enable or disable the serialization.

Signed-off-by: Guoqing Jiang <guoqing.jiang@cloud.ionos.com>
Signed-off-by: Song Liu <songliubraving@fb.com>

show more ...

md: prepare for enable raid1 io serialization

1. The related resources (spin_lock, list and waitqueue) are needed for
address raid1 reorder overlap issue too, in this case, rdev is set to
NULL for m

md: prepare for enable raid1 io serialization

1. The related resources (spin_lock, list and waitqueue) are needed for
address raid1 reorder overlap issue too, in this case, rdev is set to
NULL for mddev_create/destroy_serial_pool which implies all rdevs need
to handle these resources.

And also add "is_suspend" to mddev_destroy_serial_pool since it will
be called under suspended situation, which also makes both create and
destroy pool have same arguments.

2. Introduce rdevs_init_serial which is called if raid1 io serialization
is enabled since all rdevs need to init related stuffs.

3. rdev_init_serial and clear_bit(CollisionCheck, &rdev->flags) should
be called between suspend and resume.

No need to export mddev_create_serial_pool since it is only called in
md-mod module.

Signed-off-by: Guoqing Jiang <guoqing.jiang@cloud.ionos.com>
Signed-off-by: Song Liu <songliubraving@fb.com>

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md: fix a typo s/creat/create

It actually means create here, so fix the typo.

Reported-by: Song Liu <liu.song.a23@gmail.com>
Signed-off-by: Guoqing Jiang <guoqing.jiang@cloud.ionos.com>
Signed-off-

md: fix a typo s/creat/create

It actually means create here, so fix the typo.

Reported-by: Song Liu <liu.song.a23@gmail.com>
Signed-off-by: Guoqing Jiang <guoqing.jiang@cloud.ionos.com>
Signed-off-by: Song Liu <songliubraving@fb.com>

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md: rename wb stuffs

Previously, wb_info_pool and wb_list stuffs are introduced
to address potential data inconsistence issue for write
behind device.

Now rename them to serial related name, since

md: rename wb stuffs

Previously, wb_info_pool and wb_list stuffs are introduced
to address potential data inconsistence issue for write
behind device.

Now rename them to serial related name, since the same
mechanism will be used to address reorder overlap write
issue for raid1.

Signed-off-by: Guoqing Jiang <guoqing.jiang@cloud.ionos.com>
Signed-off-by: Song Liu <songliubraving@fb.com>

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md: make sure desc_nr less than MD_SB_DISKS

For super_90_load, we need to make sure 'desc_nr' less
than MD_SB_DISKS, avoiding invalid memory access of 'sb->disks'.

Fixes: 228fc7d76db6 ("md: avoid i

md: make sure desc_nr less than MD_SB_DISKS

For super_90_load, we need to make sure 'desc_nr' less
than MD_SB_DISKS, avoiding invalid memory access of 'sb->disks'.

Fixes: 228fc7d76db6 ("md: avoid invalid memory access for array sb->dev_roles")
Signed-off-by: Yufen Yu <yuyufen@huawei.com>
Signed-off-by: Song Liu <songliubraving@fb.com>

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md: avoid invalid memory access for array sb->dev_roles

we need to gurantee 'desc_nr' valid before access array
of sb->dev_roles.

In addition, we should avoid .load_super always return '0'
when lev

md: avoid invalid memory access for array sb->dev_roles

we need to gurantee 'desc_nr' valid before access array
of sb->dev_roles.

In addition, we should avoid .load_super always return '0'
when level is LEVEL_MULTIPATH, which is not expected.

Reported-by: coverity-bot <keescook+coverity-bot@chromium.org>
Addresses-Coverity-ID: 1487373 ("Memory - illegal accesses")
Fixes: 6a5cb53aaa4e ("md: no longer compare spare disk superblock events in super_load")
Signed-off-by: Yufen Yu <yuyufen@huawei.com>
Signed-off-by: Song Liu <songliubraving@fb.com>

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md: no longer compare spare disk superblock events in super_load

We have a test case as follow:

mdadm -CR /dev/md1 -l 1 -n 4 /dev/sd[a-d] \
--assume-clean --bitmap=internal
mdadm -S /dev/md1

md: no longer compare spare disk superblock events in super_load

We have a test case as follow:

mdadm -CR /dev/md1 -l 1 -n 4 /dev/sd[a-d] \
--assume-clean --bitmap=internal
mdadm -S /dev/md1
mdadm -A /dev/md1 /dev/sd[b-c] --run --force

mdadm --zero /dev/sda
mdadm /dev/md1 -a /dev/sda

echo offline > /sys/block/sdc/device/state
echo offline > /sys/block/sdb/device/state
sleep 5
mdadm -S /dev/md1

echo running > /sys/block/sdb/device/state
echo running > /sys/block/sdc/device/state
mdadm -A /dev/md1 /dev/sd[a-c] --run --force

When we readd /dev/sda to the array, it started to do recovery.
After offline the other two disks in md1, the recovery have
been interrupted and superblock update info cannot be written
to the offline disks. While the spare disk (/dev/sda) can continue
to update superblock info.

After stopping the array and assemble it, we found the array
run fail, with the follow kernel message:

[ 172.986064] md: kicking non-fresh sdb from array!
[ 173.004210] md: kicking non-fresh sdc from array!
[ 173.022383] md/raid1:md1: active with 0 out of 4 mirrors
[ 173.022406] md1: failed to create bitmap (-5)
[ 173.023466] md: md1 stopped.

Since both sdb and sdc have the value of 'sb->events' smaller than
that in sda, they have been kicked from the array. However, the only
remained disk sda is in 'spare' state before stop and it cannot be
added to conf->mirrors[] array. In the end, raid array assemble
and run fail.

In fact, we can use the older disk sdb or sdc to assemble the array.
That means we should not choose the 'spare' disk as the fresh disk in
analyze_sbs().

To fix the problem, we do not compare superblock events when it is
a spare disk, as same as validate_super.

Signed-off-by: Yufen Yu <yuyufen@huawei.com>
Signed-off-by: Song Liu <songliubraving@fb.com>

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md: improve handling of bio with REQ_PREFLUSH in md_flush_request()

If pers->make_request fails in md_flush_request(), the bio is lost. To
fix this, pass back a bool to indicate if the original make

md: improve handling of bio with REQ_PREFLUSH in md_flush_request()

If pers->make_request fails in md_flush_request(), the bio is lost. To
fix this, pass back a bool to indicate if the original make_request call
should continue to handle the I/O and instead of assuming the flush logic
will push it to completion.

Convert md_flush_request to return a bool and no longer calls the raid
driver's make_request function. If the return is true, then the md flush
logic has or will complete the bio and the md make_request call is done.
If false, then the md make_request function needs to keep processing like
it is a normal bio. Let the original call to md_handle_request handle any
need to retry sending the bio to the raid driver's make_request function
should it be needed.

Also mark md_flush_request and the make_request function pointer as
__must_check to issue warnings should these critical return values be
ignored.

Fixes: 2bc13b83e629 ("md: batch flush requests.")
Cc: stable@vger.kernel.org # # v4.19+
Cc: NeilBrown <neilb@suse.com>
Signed-off-by: David Jeffery <djeffery@redhat.com>
Reviewed-by: Xiao Ni <xni@redhat.com>
Signed-off-by: Song Liu <songliubraving@fb.com>

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md: add feature flag MD_FEATURE_RAID0_LAYOUT

Due to a bug introduced in Linux 3.14 we cannot determine the
correctly layout for a multi-zone RAID0 array - there are two
possibilities.

It is possibl

md: add feature flag MD_FEATURE_RAID0_LAYOUT

Due to a bug introduced in Linux 3.14 we cannot determine the
correctly layout for a multi-zone RAID0 array - there are two
possibilities.

It is possible to tell the kernel which to chose using a module
parameter, but this can be clumsy to use. It would be best if
the choice were recorded in the metadata.
So add a feature flag for this purpose.
If it is set, then the 'layout' field of the superblock is used
to determine which layout to use.

If this flag is not set, then mddev->layout gets set to -1,
which causes the module parameter to be required.

Acked-by: Guoqing Jiang <guoqing.jiang@cloud.ionos.com>
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Song Liu <songliubraving@fb.com>

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md raid0/linear: Mark array as 'broken' and fail BIOs if a member is gone

Currently md raid0/linear are not provided with any mechanism to validate
if an array member got removed or failed. The driv

md raid0/linear: Mark array as 'broken' and fail BIOs if a member is gone

Currently md raid0/linear are not provided with any mechanism to validate
if an array member got removed or failed. The driver keeps sending BIOs
regardless of the state of array members, and kernel shows state 'clean'
in the 'array_state' sysfs attribute. This leads to the following
situation: if a raid0/linear array member is removed and the array is
mounted, some user writing to this array won't realize that errors are
happening unless they check dmesg or perform one fsync per written file.
Despite udev signaling the member device is gone, 'mdadm' cannot issue the
STOP_ARRAY ioctl successfully, given the array is mounted.

In other words, no -EIO is returned and writes (except direct ones) appear
normal. Meaning the user might think the wrote data is correctly stored in
the array, but instead garbage was written given that raid0 does stripping
(and so, it requires all its members to be working in order to not corrupt
data). For md/linear, writes to the available members will work fine, but
if the writes go to the missing member(s), it'll cause a file corruption
situation, whereas the portion of the writes to the missing devices aren't
written effectively.

This patch changes this behavior: we check if the block device's gendisk
is UP when submitting the BIO to the array member, and if it isn't, we flag
the md device as MD_BROKEN and fail subsequent I/Os to that device; a read
request to the array requiring data from a valid member is still completed.
While flagging the device as MD_BROKEN, we also show a rate-limited warning
in the kernel log.

A new array state 'broken' was added too: it mimics the state 'clean' in
every aspect, being useful only to distinguish if the array has some member
missing. We rely on the MD_BROKEN flag to put the array in the 'broken'
state. This state cannot be written in 'array_state' as it just shows
one or more members of the array are missing but acts like 'clean', it
wouldn't make sense to write it.

With this patch, the filesystem reacts much faster to the event of missing
array member: after some I/O errors, ext4 for instance aborts the journal
and prevents corruption. Without this change, we're able to keep writing
in the disk and after a machine reboot, e2fsck shows some severe fs errors
that demand fixing. This patch was tested in ext4 and xfs filesystems, and
requires a 'mdadm' counterpart to handle the 'broken' state.

Cc: Song Liu <songliubraving@fb.com>
Reviewed-by: NeilBrown <neilb@suse.de>
Signed-off-by: Guilherme G. Piccoli <gpiccoli@canonical.com>
Signed-off-by: Song Liu <songliubraving@fb.com>

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md: don't report active array_state until after revalidate_disk() completes.

Until revalidate_disk() has completed, the size of a new md array will
appear to be zero.
So we shouldn't report, through

md: don't report active array_state until after revalidate_disk() completes.

Until revalidate_disk() has completed, the size of a new md array will
appear to be zero.
So we shouldn't report, through array_state, that the array is active
until that time.
udev rules check array_state to see if the array is ready. As soon as
it appear to be zero, fsck can be run. If it find the size to be
zero, it will fail.

So add a new flag to provide an interlock between do_md_run() and
array_state_show(). This flag is set while do_md_run() is active and
it prevents array_state_show() from reporting that the array is
active.

Before do_md_run() is called, ->pers will be NULL so array is
definitely not active.
After do_md_run() is called, revalidate_disk() will have run and the
array will be completely ready.

We also move various sysfs_notify*() calls out of md_run() into
do_md_run() after MD_NOT_READY is cleared. This ensure the
information is ready before the notification is sent.

Prior to v4.12, array_state_show() was called with the
mddev->reconfig_mutex held, which provided exclusion with do_md_run().

Note that MD_NOT_READY cleared twice. This is deliberate to cover
both success and error paths with minimal noise.

Fixes: b7b17c9b67e5 ("md: remove mddev_lock() from md_attr_show()")
Cc: stable@vger.kernel.org (v4.12++)
Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Song Liu <songliubraving@fb.com>

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