Comments in the code document special values used for
mddev->curr_resync. Make this clearer by using an enum to label these
values.

The only functional change is a couple places use the wrong comparison
operator that implied 3 is another special value. They are all
fixed to imply that 3 or greater is an active resync.
Signed-off-by: NLogan Gunthorpe <logang@deltatee.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NSong Liu <song@kernel.org>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Improve uniformity in the kernel of handling of request operation and
flags by passing these as a single argument.

Cc: Song Liu <song@kernel.org>
Signed-off-by: NBart Van Assche <bvanassche@acm.org>
Link: https://lore.kernel.org/r/20220714180729.1065367-32-bvanassche@acm.orgSigned-off-by: NJens Axboe <axboe@kernel.dk>

Replace the remaining calls of bdevname with snprintf using the %pg
format specifier.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NJan Kara <jack@suse.cz>
Reviewed-by: NChaitanya Kulkarni <kch@nvidia.com>
Reviewed-by: NJohannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20220713055317.1888500-10-hch@lst.deSigned-off-by: NJens Axboe <axboe@kernel.dk>

blk_cleanup_disk is nothing but a trivial wrapper for put_disk now,
so remove it.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NHannes Reinecke <hare@suse.de>
Link: https://lore.kernel.org/r/20220619060552.1850436-7-hch@lst.deSigned-off-by: NJens Axboe <axboe@kernel.dk>

The 07reshape5intr test is broke because of below path.

    md_reap_sync_thread
            -> mddev_unlock
            -> md_unregister_thread(&mddev->sync_thread)

And md_check_recovery is triggered by,

mddev_unlock -> md_wakeup_thread(mddev->thread)

then mddev->reshape_position is set to MaxSector in raid5_finish_reshape
since MD_RECOVERY_INTR is cleared in md_check_recovery, which means
feature_map is not set with MD_FEATURE_RESHAPE_ACTIVE and superblock's
reshape_position can't be updated accordingly.

Fixes: 8b48ec23 ("md: don't unregister sync_thread with reconfig_mutex held")
Reported-by: NLogan Gunthorpe <logang@deltatee.com>
Signed-off-by: NGuoqing Jiang <guoqing.jiang@linux.dev>
Signed-off-by: NSong Liu <song@kernel.org>

Now io_acct_set is alloc and free in personality. Remove the codes that
free io_acct_set in md_free and md_stop.

Fixes: 0c031fd3 (md: Move alloc/free acct bioset in to personality)
Signed-off-by: NXiao Ni <xni@redhat.com>
Signed-off-by: NSong Liu <song@kernel.org>

Use the %pg format specifier to save on stack consumption and code size.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NSong Liu <song@kernel.org>

Generally, the md_unregister_thread is called with reconfig_mutex, but
raid_message in dm-raid doesn't hold reconfig_mutex to unregister thread,
so md_unregister_thread can be called simulitaneously from two call sites
in theory.

Then after previous commit which remove the protection of reconfig_mutex
for md_unregister_thread completely, the potential issue could be worse
than before.

Let's take pers_lock at the beginning of function to ensure reentrancy.
Reported-by: NDonald Buczek <buczek@molgen.mpg.de>
Signed-off-by: NGuoqing Jiang <guoqing.jiang@linux.dev>
Signed-off-by: NSong Liu <song@kernel.org>

Unregister sync_thread doesn't need to hold reconfig_mutex since it
doesn't reconfigure array.

And it could cause deadlock problem for raid5 as follows:

1. process A tried to reap sync thread with reconfig_mutex held after echo
   idle to sync_action.
2. raid5 sync thread was blocked if there were too many active stripes.
3. SB_CHANGE_PENDING was set (because of write IO comes from upper layer)
   which causes the number of active stripes can't be decreased.
4. SB_CHANGE_PENDING can't be cleared since md_check_recovery was not able
   to hold reconfig_mutex.

More details in the link:
https://lore.kernel.org/linux-raid/5ed54ffc-ce82-bf66-4eff-390cb23bc1ac@molgen.mpg.de/T/#t

And add one parameter to md_reap_sync_thread since it could be called by
dm-raid which doesn't hold reconfig_mutex.
Reported-and-tested-by: NDonald Buczek <buczek@molgen.mpg.de>
Signed-off-by: NGuoqing Jiang <guoqing.jiang@cloud.ionos.com>
Signed-off-by: NSong Liu <song@kernel.org>

There are several instances where magic numbers are used in md.c instead
of the defined constants in md_p.h. This patch set improves code
readability by replacing all occurrences of 0xffff, 0xfffe, and 0xfffd when
relating to md roles with their equivalent defined constant.
Signed-off-by: NDavid Sloan <david.sloan@eideticom.com>
Reviewed-by: NLogan Gunthorpe <logang@deltatee.com>
Signed-off-by: NSong Liu <song@kernel.org>

This commit includes two topics:

1> replace deprecated strlcpy

change strlcpy to strscpy for strlcpy is marked as deprecated in
Documentation/process/deprecated.rst

2> remove duplicated strlcpy line

in md_bitmap_read_sb@md-bitmap.c there are two duplicated strlcpy(), the
history:

- commit cf921cc1 ("Add node recovery callbacks") introduced the first
  usage of strlcpy().

- commit b97e9257 ("Use separate bitmaps for each nodes in the cluster")
  introduced the second strlcpy(). this time, the two strlcpy() are same,
   we can remove anyone safely.

- commit d3b178ad ("md: Skip cluster setup for dm-raid") added dm-raid
  special handling. And the "nodes" value is the key of this patch. but
  from this patch, strlcpy() which was introduced by b97e9257
  become necessary.

- commit 3c462c88 ("md: Increment version for clustered bitmaps") used
  clustered major version to only handle in clustered env. this patch
  could look a polishment for clustered code logic.

So cf921cc1 became useless after d3b178ad, we could remove it
safely.
Signed-off-by: NHeming Zhao <heming.zhao@suse.com>
Signed-off-by: NSong Liu <song@kernel.org>

The bug is here:
	if (!rdev || rdev->desc_nr != nr) {

The list iterator value 'rdev' will *always* be set and non-NULL
by rdev_for_each_rcu(), so it is incorrect to assume that the
iterator value will be NULL if the list is empty or no element
found (In fact, it will be a bogus pointer to an invalid struct
object containing the HEAD). Otherwise it will bypass the check
and lead to invalid memory access passing the check.

To fix the bug, use a new variable 'iter' as the list iterator,
while using the original variable 'pdev' as a dedicated pointer to
point to the found element.

Cc: stable@vger.kernel.org
Fixes: 70bcecdb ("md-cluster: Improve md_reload_sb to be less error prone")
Signed-off-by: NXiaomeng Tong <xiam0nd.tong@gmail.com>
Signed-off-by: NSong Liu <song@kernel.org>

The bug is here:
	if (!rdev)

The list iterator value 'rdev' will *always* be set and non-NULL
by rdev_for_each(), so it is incorrect to assume that the iterator
value will be NULL if the list is empty or no element found.
Otherwise it will bypass the NULL check and lead to invalid memory
access passing the check.

To fix the bug, use a new variable 'iter' as the list iterator,
while using the original variable 'rdev' as a dedicated pointer to
point to the found element.

Cc: stable@vger.kernel.org
Fixes: 2aa82191 ("md-cluster: Perform a lazy update")
Acked-by: NGuoqing Jiang <guoqing.jiang@linux.dev>
Signed-off-by: NXiaomeng Tong <xiam0nd.tong@gmail.com>
Acked-by: NGoldwyn Rodrigues <rgoldwyn@suse.com>
Signed-off-by: NSong Liu <song@kernel.org>

There is no direct mechanism to determine raid failure outside
personality. It is done by checking rdev->flags after executing
md_error(). If "faulty" flag is not set then -EBUSY is returned to
userspace. -EBUSY means that array will be failed after drive removal.

Mdadm has special routine to handle the array failure and it is executed
if -EBUSY is returned by md.

There are at least two known reasons to not consider this mechanism
as correct:
1. drive can be removed even if array will be failed[1].
2. -EBUSY seems to be wrong status. Array is not busy, but removal
   process cannot proceed safe.

-EBUSY expectation cannot be removed without breaking compatibility
with userspace. In this patch first issue is resolved by adding support
for MD_BROKEN flag for RAID1 and RAID10. Support for RAID456 is added in
next commit.

The idea is to set the MD_BROKEN if we are sure that raid is in failed
state now. This is done in each error_handler(). In md_error() MD_BROKEN
flag is checked. If is set, then -EBUSY is returned to userspace.

As in previous commit, it causes that #mdadm --set-faulty is able to
fail array. Previously proposed workaround is valid if optional
functionality[1] is disabled.

[1] commit 9a567843("md: allow last device to be forcibly removed from
    RAID1/RAID10.")
Reviewd-by: NXiao Ni <xni@redhat.com>
Signed-off-by: NMariusz Tkaczyk <mariusz.tkaczyk@linux.intel.com>
Signed-off-by: NSong Liu <song@kernel.org>

Secure erase is a very different operation from discard in that it is
a data integrity operation vs hint.  Fully split the limits and helper
infrastructure to make the separation more clear.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NMartin K. Petersen <martin.petersen@oracle.com>
Acked-by: Christoph Böhmwalder <christoph.boehmwalder@linbit.com> [drbd]
Acked-by: Ryusuke Konishi <konishi.ryusuke@gmail.com> [nifs2]
Acked-by: Jaegeuk Kim <jaegeuk@kernel.org> [f2fs]
Acked-by: Coly Li <colyli@suse.de> [bcache]
Acked-by: David Sterba <dsterba@suse.com> [btrfs]
Acked-by: NChao Yu <chao@kernel.org>
Reviewed-by: NChaitanya Kulkarni <kch@nvidia.com>
Link: https://lore.kernel.org/r/20220415045258.199825-27-hch@lst.deSigned-off-by: NJens Axboe <axboe@kernel.dk>

Add a helper to check the nonrot flag based on the block_device instead
of having to poke into the block layer internal request_queue.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NMartin K. Petersen <martin.petersen@oracle.com>
Acked-by: David Sterba <dsterba@suse.com> [btrfs]
Reviewed-by: NChaitanya Kulkarni <kch@nvidia.com>
Link: https://lore.kernel.org/r/20220415045258.199825-12-hch@lst.deSigned-off-by: NJens Axboe <axboe@kernel.dk>

Calling mdelay(1000) from process context, even while a reboot
is in progress, does not make sense.

Using msleep() allows other threads to make progress.
Signed-off-by: NEric Dumazet <edumazet@google.com>
Cc: linux-raid@vger.kernel.org
Signed-off-by: NSong Liu <song@kernel.org>

Pass a block_device to bio_clone_fast and __bio_clone_fast and give
the functions more suitable names.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NMike Snitzer <snitzer@redhat.com>
Link: https://lore.kernel.org/r/20220202160109.108149-14-hch@lst.deSigned-off-by: NJens Axboe <axboe@kernel.dk>

Leon reported NULL pointer deref with nowait support:

[   15.123761] device-mapper: raid: Loading target version 1.15.1
[   15.124185] device-mapper: raid: Ignoring chunk size parameter for RAID 1
[   15.124192] device-mapper: raid: Choosing default region size of 4MiB
[   15.129524] BUG: kernel NULL pointer dereference, address: 0000000000000060
[   15.129530] #PF: supervisor write access in kernel mode
[   15.129533] #PF: error_code(0x0002) - not-present page
[   15.129535] PGD 0 P4D 0
[   15.129538] Oops: 0002 [#1] PREEMPT SMP NOPTI
[   15.129541] CPU: 5 PID: 494 Comm: ldmtool Not tainted 5.17.0-rc2-1-mainline #1 9fe89d43dfcb215d2731e6f8851740520778615e
[   15.129546] Hardware name: Gigabyte Technology Co., Ltd. X570 AORUS ELITE/X570 AORUS ELITE, BIOS F36e 10/14/2021
[   15.129549] RIP: 0010:blk_queue_flag_set+0x7/0x20
[   15.129555] Code: 00 00 00 0f 1f 44 00 00 48 8b 35 e4 e0 04 02 48 8d 57 28 bf 40 01 \
       00 00 e9 16 c1 be ff 66 0f 1f 44 00 00 0f 1f 44 00 00 89 ff <f0> 48 0f ab 7e 60 \
       31 f6 89 f7 c3 66 66 2e 0f 1f 84 00 00 00 00 00
[   15.129559] RSP: 0018:ffff966b81987a88 EFLAGS: 00010202
[   15.129562] RAX: ffff8b11c363a0d0 RBX: ffff8b11e294b070 RCX: 0000000000000000
[   15.129564] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 000000000000001d
[   15.129566] RBP: ffff8b11e294b058 R08: 0000000000000000 R09: 0000000000000000
[   15.129568] R10: 0000000000000000 R11: 0000000000000000 R12: ffff8b11e294b070
[   15.129570] R13: 0000000000000000 R14: ffff8b11e294b000 R15: 0000000000000001
[   15.129572] FS:  00007fa96e826780(0000) GS:ffff8b18deb40000(0000) knlGS:0000000000000000
[   15.129575] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   15.129577] CR2: 0000000000000060 CR3: 000000010b8ce000 CR4: 00000000003506e0
[   15.129580] Call Trace:
[   15.129582]  <TASK>
[   15.129584]  md_run+0x67c/0xc70 [md_mod 1e470c1b6bcf1114198109f42682f5a2740e9531]
[   15.129597]  raid_ctr+0x134a/0x28ea [dm_raid 6a645dd7519e72834bd7e98c23497eeade14cd63]
[   15.129604]  ? dm_split_args+0x63/0x150 [dm_mod 0d7b0bc3414340a79c4553bae5ca97294b78336e]
[   15.129615]  dm_table_add_target+0x188/0x380 [dm_mod 0d7b0bc3414340a79c4553bae5ca97294b78336e]
[   15.129625]  table_load+0x13b/0x370 [dm_mod 0d7b0bc3414340a79c4553bae5ca97294b78336e]
[   15.129635]  ? dev_suspend+0x2d0/0x2d0 [dm_mod 0d7b0bc3414340a79c4553bae5ca97294b78336e]
[   15.129644]  ctl_ioctl+0x1bd/0x460 [dm_mod 0d7b0bc3414340a79c4553bae5ca97294b78336e]
[   15.129655]  dm_ctl_ioctl+0xa/0x20 [dm_mod 0d7b0bc3414340a79c4553bae5ca97294b78336e]
[   15.129663]  __x64_sys_ioctl+0x8e/0xd0
[   15.129667]  do_syscall_64+0x5c/0x90
[   15.129672]  ? syscall_exit_to_user_mode+0x23/0x50
[   15.129675]  ? do_syscall_64+0x69/0x90
[   15.129677]  ? do_syscall_64+0x69/0x90
[   15.129679]  ? syscall_exit_to_user_mode+0x23/0x50
[   15.129682]  ? do_syscall_64+0x69/0x90
[   15.129684]  ? do_syscall_64+0x69/0x90
[   15.129686]  entry_SYSCALL_64_after_hwframe+0x44/0xae
[   15.129689] RIP: 0033:0x7fa96ecd559b
[   15.129692] Code: ff ff ff 85 c0 79 9b 49 c7 c4 ff ff ff ff 5b 5d 4c 89 e0 41 5c \
    c3 66 0f 1f 84 00 00 00 00 00 f3 0f 1e fa b8 10 00 00 00 0f 05 <48> 3d 01 f0 ff \
    ff 73 01 c3 48 8b 0d a5 a8 0c 00 f7 d8 64 89 01 48
[   15.129696] RSP: 002b:00007ffcaf85c258 EFLAGS: 00000206 ORIG_RAX: 0000000000000010
[   15.129699] RAX: ffffffffffffffda RBX: 00007fa96f1b48f0 RCX: 00007fa96ecd559b
[   15.129701] RDX: 00007fa97017e610 RSI: 00000000c138fd09 RDI: 0000000000000003
[   15.129702] RBP: 00007fa96ebab583 R08: 00007fa97017c9e0 R09: 00007ffcaf85bf27
[   15.129704] R10: 0000000000000001 R11: 0000000000000206 R12: 00007fa97017e610
[   15.129706] R13: 00007fa97017e640 R14: 00007fa97017e6c0 R15: 00007fa97017e530
[   15.129709]  </TASK>

This is caused by missing mddev->queue check for setting QUEUE_FLAG_NOWAIT
Fix this by moving the QUEUE_FLAG_NOWAIT logic to under mddev->queue check.

Fixes: f51d46d0 ("md: add support for REQ_NOWAIT")
Reported-by: NLeon Möller <jkhsjdhjs@totally.rip>
Tested-by: NLeon Möller <jkhsjdhjs@totally.rip>
Cc: Vishal Verma <vverma@digitalocean.com>
Signed-off-by: NSong Liu <song@kernel.org>

Pass the block_device that we plan to use this bio for and the
operation to bio_init to optimize the assignment.  A NULL block_device
can be passed, both for the passthrough case on a raw request_queue and
to temporarily avoid refactoring some nasty code.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NChaitanya Kulkarni <kch@nvidia.com>
Link: https://lore.kernel.org/r/20220124091107.642561-19-hch@lst.deSigned-off-by: NJens Axboe <axboe@kernel.dk>

Pass the block_device and operation that we plan to use this bio for to
bio_alloc_bioset to optimize the assigment.  NULL/0 can be passed, both
for the passthrough case on a raw request_queue and to temporarily avoid
refactoring some nasty code.

Also move the gfp_mask argument after the nr_vecs argument for a much
more logical calling convention matching what most of the kernel does.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NChaitanya Kulkarni <kch@nvidia.com>
Link: https://lore.kernel.org/r/20220124091107.642561-16-hch@lst.deSigned-off-by: NJens Axboe <axboe@kernel.dk>

There are currently 2 ways to create a set of sysfs files for a
kobj_type, through the default_attrs field, and the default_groups
field.  Move the md rdev sysfs code to use default_groups field which
has been the preferred way since commit aa30f47c ("kobject: Add
support for default attribute groups to kobj_type") so that we can soon
get rid of the obsolete default_attrs field.

Cc: Song Liu <song@kernel.org>
Cc: linux-raid@vger.kernel.org
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NSong Liu <song@kernel.org>

bioset acct is only needed for raid0 and raid5. Therefore, md_run only
allocates it for raid0 and raid5. However, this does not cover
personality takeover, which may cause uninitialized bioset. For example,
the following repro steps:

  mdadm -CR /dev/md0 -l1 -n2 /dev/loop0 /dev/loop1
  mdadm --wait /dev/md0
  mkfs.xfs /dev/md0
  mdadm /dev/md0 --grow -l5
  mount /dev/md0 /mnt

causes panic like:

[  225.933939] BUG: kernel NULL pointer dereference, address: 0000000000000000
[  225.934903] #PF: supervisor instruction fetch in kernel mode
[  225.935639] #PF: error_code(0x0010) - not-present page
[  225.936361] PGD 0 P4D 0
[  225.936677] Oops: 0010 [#1] PREEMPT SMP DEBUG_PAGEALLOC KASAN PTI
[  225.937525] CPU: 27 PID: 1133 Comm: mount Not tainted 5.16.0-rc3+ #706
[  225.938416] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-2.module_el8.4.0+547+a85d02ba 04/01/2014
[  225.939922] RIP: 0010:0x0
[  225.940289] Code: Unable to access opcode bytes at RIP 0xffffffffffffffd6.
[  225.941196] RSP: 0018:ffff88815897eff0 EFLAGS: 00010246
[  225.941897] RAX: 0000000000000000 RBX: 0000000000092800 RCX: ffffffff81370a39
[  225.942813] RDX: dffffc0000000000 RSI: 0000000000000000 RDI: 0000000000092800
[  225.943772] RBP: 1ffff1102b12fe04 R08: fffffbfff0b43c01 R09: fffffbfff0b43c01
[  225.944807] R10: ffffffff85a1e007 R11: fffffbfff0b43c00 R12: ffff88810eaaaf58
[  225.945757] R13: 0000000000000000 R14: ffff88810eaaafb8 R15: ffff88815897f040
[  225.946709] FS:  00007ff3f2505080(0000) GS:ffff888fb5e00000(0000) knlGS:0000000000000000
[  225.947814] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  225.948556] CR2: ffffffffffffffd6 CR3: 000000015aa5a006 CR4: 0000000000370ee0
[  225.949537] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[  225.950455] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[  225.951414] Call Trace:
[  225.951787]  <TASK>
[  225.952120]  mempool_alloc+0xe5/0x250
[  225.952625]  ? mempool_resize+0x370/0x370
[  225.953187]  ? rcu_read_lock_sched_held+0xa1/0xd0
[  225.953862]  ? rcu_read_lock_bh_held+0xb0/0xb0
[  225.954464]  ? sched_clock_cpu+0x15/0x120
[  225.955019]  ? find_held_lock+0xac/0xd0
[  225.955564]  bio_alloc_bioset+0x1ed/0x2a0
[  225.956080]  ? lock_downgrade+0x3a0/0x3a0
[  225.956644]  ? bvec_alloc+0xc0/0xc0
[  225.957135]  bio_clone_fast+0x19/0x80
[  225.957651]  raid5_make_request+0x1370/0x1b70
[  225.958286]  ? sched_clock_cpu+0x15/0x120
[  225.958797]  ? __lock_acquire+0x8b2/0x3510
[  225.959339]  ? raid5_get_active_stripe+0xce0/0xce0
[  225.959986]  ? lock_is_held_type+0xd8/0x130
[  225.960528]  ? rcu_read_lock_sched_held+0xa1/0xd0
[  225.961135]  ? rcu_read_lock_bh_held+0xb0/0xb0
[  225.961703]  ? sched_clock_cpu+0x15/0x120
[  225.962232]  ? lock_release+0x27a/0x6c0
[  225.962746]  ? do_wait_intr_irq+0x130/0x130
[  225.963302]  ? lock_downgrade+0x3a0/0x3a0
[  225.963815]  ? lock_release+0x6c0/0x6c0
[  225.964348]  md_handle_request+0x342/0x530
[  225.964888]  ? set_in_sync+0x170/0x170
[  225.965397]  ? blk_queue_split+0x133/0x150
[  225.965988]  ? __blk_queue_split+0x8b0/0x8b0
[  225.966524]  ? submit_bio_checks+0x3b2/0x9d0
[  225.967069]  md_submit_bio+0x127/0x1c0
[...]

Fix this by moving alloc/free of acct bioset to pers->run and pers->free.

While we are on this, properly handle md_integrity_register() error in
raid0_run().

Fixes: daee2024 (md: check level before create and exit io_acct_set)
Cc: stable@vger.kernel.org
Acked-by: NGuoqing Jiang <guoqing.jiang@linux.dev>
Signed-off-by: NXiao Ni <xni@redhat.com>
Signed-off-by: NSong Liu <song@kernel.org>

Use the possessive "its" instead of the contraction "it's"
in printed messages.
Signed-off-by: NRandy Dunlap <rdunlap@infradead.org>
Cc: Song Liu <song@kernel.org>
Cc: linux-raid@vger.kernel.org
Signed-off-by: NSong Liu <song@kernel.org>

commit 021a2446 ("block: add QUEUE_FLAG_NOWAIT") added support
for checking whether a given bdev supports handling of REQ_NOWAIT or not.
Since then commit 6abc4946 ("dm: add support for REQ_NOWAIT and enable
it for linear target") added support for REQ_NOWAIT for dm. This uses
a similar approach to incorporate REQ_NOWAIT for md based bios.

This patch was tested using t/io_uring tool within FIO. A nvme drive
was partitioned into 2 partitions and a simple raid 0 configuration
/dev/md0 was created.

md0 : active raid0 nvme4n1p1[1] nvme4n1p2[0]
      937423872 blocks super 1.2 512k chunks

Before patch:

$ ./t/io_uring /dev/md0 -p 0 -a 0 -d 1 -r 100

Running top while the above runs:

$ ps -eL | grep $(pidof io_uring)

  38396   38396 pts/2    00:00:00 io_uring
  38396   38397 pts/2    00:00:15 io_uring
  38396   38398 pts/2    00:00:13 iou-wrk-38397

We can see iou-wrk-38397 io worker thread created which gets created
when io_uring sees that the underlying device (/dev/md0 in this case)
doesn't support nowait.

After patch:

$ ./t/io_uring /dev/md0 -p 0 -a 0 -d 1 -r 100

Running top while the above runs:

$ ps -eL | grep $(pidof io_uring)

  38341   38341 pts/2    00:10:22 io_uring
  38341   38342 pts/2    00:10:37 io_uring

After running this patch, we don't see any io worker thread
being created which indicated that io_uring saw that the
underlying device does support nowait. This is the exact behaviour
noticed on a dm device which also supports nowait.

For all the other raid personalities except raid0, we would need
to train pieces which involves make_request fn in order for them
to correctly handle REQ_NOWAIT.
Reviewed-by: NJens Axboe <axboe@kernel.dk>
Signed-off-by: NVishal Verma <vverma@digitalocean.com>
Signed-off-by: NSong Liu <song@kernel.org>

In driver/md/md.c, if the function autorun_array() is called,
the problem of double free may occur.

In function autorun_array(), when the function do_md_run() returns an
error, the function do_md_stop() will be called.

The function do_md_run() called function md_run(), but in function
md_run(), the pointer mddev->private may be freed.

The function do_md_stop() called the function __md_stop(), but in
function __md_stop(), the pointer mddev->private also will be freed
without judging null.

At this time, the pointer mddev->private will be double free, so it
needs to be judged null or not.
Signed-off-by: Nzhangyue <zhangyue1@kylinos.cn>
Signed-off-by: NSong Liu <songliubraving@fb.com>

The superblock of version 1.0 doesn't get moved to the new position on a
device size change. This leads to a rdev without a superblock on a known
position, the raid can't be re-assembled.

The line was removed by mistake and is re-added by this patch.

Fixes: d9c0fa50 ("md: fix max sectors calculation for super 1.0")
Cc: stable@vger.kernel.org
Signed-off-by: NMarkus Hochholdinger <markus@hochholdinger.net>
Reviewed-by: NXiao Ni <xni@redhat.com>
Signed-off-by: NSong Liu <songliubraving@fb.com>

All modern drivers can support extra partitions using the extended
dev_t.  In fact except for the ioctl method drivers never even see
partitions in normal operation.

So remove the GENHD_FL_EXT_DEVT and allow extra partitions for all
block devices that do support partitions, and require those that
do not support partitions to explicit disallow them using
GENHD_FL_NO_PART.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20211122130625.1136848-12-hch@lst.deSigned-off-by: NJens Axboe <axboe@kernel.dk>

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: NLi Feng <fengli@smartx.com>
Signed-off-by: NXiao Ni <xni@redhat.com>
Signed-off-by: NSong Liu <songliubraving@fb.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Actually, mddev is not used by md_new_event.
Signed-off-by: NGuoqing Jiang <guoqing.jiang@linux.dev>
Signed-off-by: NSong Liu <songliubraving@fb.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Add proper error handling to delete the gendisk when failing to add
the md kobject and clean up the error unwinding in general.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NSong Liu <songliubraving@fb.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

disks_mutex is intended to serialize md_alloc.  Extended it to also cover
the kobject_uevent call and getting the sysfs dirent to help reducing
error handling complexity.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NSong Liu <songliubraving@fb.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Replace the deprecated default_attrs with the default_groups mechanism,
and add the always visible bitmap group to the groups created add
kobject_add time.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NSong Liu <songliubraving@fb.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

We never checked for errors on add_disk() as this function
returned void. Now that this is fixed, use the shiny new
error handling.

We just do the unwinding of what was not done before, and are
sure to unlock prior to bailing.
Signed-off-by: NLuis Chamberlain <mcgrof@kernel.org>
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NSong Liu <songliubraving@fb.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Use the proper helper to read the block device size.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NKees Cook <keescook@chromium.org>
Acked-by: NSong Liu <song@kernel.org>
Link: https://lore.kernel.org/r/20211018101130.1838532-7-hch@lst.deSigned-off-by: NJens Axboe <axboe@kernel.dk>

Replace the blk_poll interface that requires the caller to keep a queue
and cookie from the submissions with polling based on the bio.

Polling for the bio itself leads to a few advantages:

 - the cookie construction can made entirely private in blk-mq.c
 - the caller does not need to remember the request_queue and cookie
   separately and thus sidesteps their lifetime issues
 - keeping the device and the cookie inside the bio allows to trivially
   support polling BIOs remapping by stacking drivers
 - a lot of code to propagate the cookie back up the submission path can
   be removed entirely.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Tested-by: NMark Wunderlich <mark.wunderlich@intel.com>
Link: https://lore.kernel.org/r/20211012111226.760968-15-hch@lst.deSigned-off-by: NJens Axboe <axboe@kernel.dk>

Split the integrity/metadata handling definitions out into a new header.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NJohannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20210920123328.1399408-17-hch@lst.deSigned-off-by: NJens Axboe <axboe@kernel.dk>

Drop various include not actually used in genhd.h itself, and
move the remaning includes closer together.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NJohannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20210920123328.1399408-15-hch@lst.deSigned-off-by: NJens Axboe <axboe@kernel.dk>

Commit b0140891 ("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: b0140891 ("md: Fix race when creating a new md device.")
Fixes: d6263387 ("block: support delayed holder registration")
Reported-by: syzbot+fadc0aaf497e6a493b9f@syzkaller.appspotmail.com
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Tested-by: syzbot+fadc0aaf497e6a493b9f@syzkaller.appspotmail.com
Reviewed-by: NNeilBrown <neilb@suse.de>
Signed-off-by: NSong Liu <songliubraving@fb.com>

Given it is not obvious for the error handling, let's try to add some
comments here to make it clear.
Signed-off-by: NGuoqing Jiang <jiangguoqing@kylinos.cn>
Signed-off-by: NSong Liu <song@kernel.org>