linux.git/drivers/md/md.c, branch v6.9

Merge tag 'for-6.9/block-20240310' of git://git.kernel.dk/linux

2024-03-11T18:43:44+00:00

Pull block updates from Jens Axboe:

 - MD pull requests via Song:
      - Cleanup redundant checks (Yu Kuai)
      - Remove deprecated headers (Marc Zyngier, Song Liu)
      - Concurrency fixes (Li Lingfeng)
      - Memory leak fix (Li Nan)
      - Refactor raid1 read_balance (Yu Kuai, Paul Luse)
      - Clean up and fix for md_ioctl (Li Nan)
      - Other small fixes (Gui-Dong Han, Heming Zhao)
      - MD atomic limits (Christoph)

 - NVMe pull request via Keith:
      - RDMA target enhancements (Max)
      - Fabrics fixes (Max, Guixin, Hannes)
      - Atomic queue_limits usage (Christoph)
      - Const use for class_register (Ricardo)
      - Identification error handling fixes (Shin'ichiro, Keith)

 - Improvement and cleanup for cached request handling (Christoph)

 - Moving towards atomic queue limits. Core changes and driver bits so
   far (Christoph)

 - Fix UAF issues in aoeblk (Chun-Yi)

 - Zoned fix and cleanups (Damien)

 - s390 dasd cleanups and fixes (Jan, Miroslav)

 - Block issue timestamp caching (me)

 - noio scope guarding for zoned IO (Johannes)

 - block/nvme PI improvements (Kanchan)

 - Ability to terminate long running discard loop (Keith)

 - bdev revalidation fix (Li)

 - Get rid of old nr_queues hack for kdump kernels (Ming)

 - Support for async deletion of ublk (Ming)

 - Improve IRQ bio recycling (Pavel)

 - Factor in CPU capacity for remote vs local completion (Qais)

 - Add shared_tags configfs entry for null_blk (Shin'ichiro

 - Fix for a regression in page refcounts introduced by the folio
   unification (Tony)

 - Misc fixes and cleanups (Arnd, Colin, John, Kunwu, Li, Navid,
   Ricardo, Roman, Tang, Uwe)

* tag 'for-6.9/block-20240310' of git://git.kernel.dk/linux: (221 commits)
  block: partitions: only define function mac_fix_string for CONFIG_PPC_PMAC
  block/swim: Convert to platform remove callback returning void
  cdrom: gdrom: Convert to platform remove callback returning void
  block: remove disk_stack_limits
  md: remove mddev->queue
  md: don't initialize queue limits
  md/raid10: use the atomic queue limit update APIs
  md/raid5: use the atomic queue limit update APIs
  md/raid1: use the atomic queue limit update APIs
  md/raid0: use the atomic queue limit update APIs
  md: add queue limit helpers
  md: add a mddev_is_dm helper
  md: add a mddev_add_trace_msg helper
  md: add a mddev_trace_remap helper
  bcache: move calculation of stripe_size and io_opt into bcache_device_init
  virtio_blk: Do not use disk_set_max_open/active_zones()
  aoe: fix the potential use-after-free problem in aoecmd_cfg_pkts
  block: move capacity validation to blkpg_do_ioctl()
  block: prevent division by zero in blk_rq_stat_sum()
  drbd: atomically update queue limits in drbd_reconsider_queue_parameters
  ...

Merge tag 'vfs-6.9.super' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs

2024-03-11T17:52:34+00:00

Pull block handle updates from Christian Brauner:
 "Last cycle we changed opening of block devices, and opening a block
  device would return a bdev_handle. This allowed us to implement
  support for restricting and forbidding writes to mounted block
  devices. It was accompanied by converting and adding helpers to
  operate on bdev_handles instead of plain block devices.

  That was already a good step forward but ultimately it isn't necessary
  to have special purpose helpers for opening block devices internally
  that return a bdev_handle.

  Fundamentally, opening a block device internally should just be
  equivalent to opening files. So now all internal opens of block
  devices return files just as a userspace open would. Instead of
  introducing a separate indirection into bdev_open_by_*() via struct
  bdev_handle bdev_file_open_by_*() is made to just return a struct
  file. Opening and closing a block device just becomes equivalent to
  opening and closing a file.

  This all works well because internally we already have a pseudo fs for
  block devices and so opening block devices is simple. There's a few
  places where we needed to be careful such as during boot when the
  kernel is supposed to mount the rootfs directly without init doing it.
  Here we need to take care to ensure that we flush out any asynchronous
  file close. That's what we already do for opening, unpacking, and
  closing the initramfs. So nothing new here.

  The equivalence of opening and closing block devices to regular files
  is a win in and of itself. But it also has various other advantages.
  We can remove struct bdev_handle completely. Various low-level helpers
  are now private to the block layer. Other helpers were simply
  removable completely.

  A follow-up series that is already reviewed build on this and makes it
  possible to remove bdev->bd_inode and allows various clean ups of the
  buffer head code as well. All places where we stashed a bdev_handle
  now just stash a file and use simple accessors to get to the actual
  block device which was already the case for bdev_handle"

* tag 'vfs-6.9.super' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (35 commits)
  block: remove bdev_handle completely
  block: don't rely on BLK_OPEN_RESTRICT_WRITES when yielding write access
  bdev: remove bdev pointer from struct bdev_handle
  bdev: make struct bdev_handle private to the block layer
  bdev: make bdev_{release, open_by_dev}() private to block layer
  bdev: remove bdev_open_by_path()
  reiserfs: port block device access to file
  ocfs2: port block device access to file
  nfs: port block device access to files
  jfs: port block device access to file
  f2fs: port block device access to files
  ext4: port block device access to file
  erofs: port device access to file
  btrfs: port device access to file
  bcachefs: port block device access to file
  target: port block device access to file
  s390: port block device access to file
  nvme: port block device access to file
  block2mtd: port device access to files
  bcache: port block device access to files
  ...

md: remove mddev->queue

2024-03-06T16:59:53+00:00

Just use the request_queue from the gendisk pointer in the relatively
few places that sill need it.

Signed-off-by: Christoph Hellwig 
Reviewed--by: Song Liu 
Tested-by: Song Liu 
Signed-off-by: Song Liu 
Link: https://lore.kernel.org/r/20240303140150.5435-11-hch@lst.de

md: don't initialize queue limits

2024-03-06T16:59:53+00:00

Initial queue limits are now set from ->run.  Remove the superfluous
initialization in md_alloc and level_store.

Signed-off-by: Christoph Hellwig 
Reviewed--by: Song Liu 
Tested-by: Song Liu 
Signed-off-by: Song Liu 
Link: https://lore.kernel.org/r/20240303140150.5435-10-hch@lst.de

md: add queue limit helpers

2024-03-06T16:59:53+00:00

Add a few helpers that wrap the block queue limits API for use in MD.

Signed-off-by: Christoph Hellwig 
Reviewed--by: Song Liu 
Tested-by: Song Liu 
Signed-off-by: Song Liu 
Link: https://lore.kernel.org/r/20240303140150.5435-5-hch@lst.de

md: add a mddev_is_dm helper

2024-03-06T16:59:53+00:00

Add a helper to check for a DM-mapped MD device instead of using
the obfuscated ->gendisk or ->queue NULL checks.

Signed-off-by: Christoph Hellwig 
Reviewed--by: Song Liu 
Tested-by: Song Liu 
Signed-off-by: Song Liu 
Link: https://lore.kernel.org/r/20240303140150.5435-4-hch@lst.de

md: add a mddev_add_trace_msg helper

2024-03-06T16:59:52+00:00

Add a small wrapper around blk_add_trace_msg that hides some argument
dereferences and the check for a DM-mapped MD device.

Signed-off-by: Christoph Hellwig 
Reviewed--by: Song Liu 
Tested-by: Song Liu 
Signed-off-by: Song Liu 
Link: https://lore.kernel.org/r/20240303140150.5435-3-hch@lst.de

md: add a mddev_trace_remap helper

2024-03-06T16:59:52+00:00

Add a helper to trace bio remapping that hides some argument
dereferences and the check for a DM-mapped MD device.

Signed-off-by: Christoph Hellwig 
Reviewed--by: Song Liu 
Tested-by: Song Liu 
Signed-off-by: Song Liu 
Link: https://lore.kernel.org/r/20240303140150.5435-2-hch@lst.de

dm-raid456, md/raid456: fix a deadlock for dm-raid456 while io concurrent with reshape

2024-03-05T20:53:33+00:00

For raid456, if reshape is still in progress, then IO across reshape
position will wait for reshape to make progress. However, for dm-raid,
in following cases reshape will never make progress hence IO will hang:

1) the array is read-only;
2) MD_RECOVERY_WAIT is set;
3) MD_RECOVERY_FROZEN is set;

After commit c467e97f079f ("md/raid6: use valid sector values to determine
if an I/O should wait on the reshape") fix the problem that IO across
reshape position doesn't wait for reshape, the dm-raid test
shell/lvconvert-raid-reshape.sh start to hang:

[root@fedora ~]# cat /proc/979/stack
[<0>] wait_woken+0x7d/0x90
[<0>] raid5_make_request+0x929/0x1d70 [raid456]
[<0>] md_handle_request+0xc2/0x3b0 [md_mod]
[<0>] raid_map+0x2c/0x50 [dm_raid]
[<0>] __map_bio+0x251/0x380 [dm_mod]
[<0>] dm_submit_bio+0x1f0/0x760 [dm_mod]
[<0>] __submit_bio+0xc2/0x1c0
[<0>] submit_bio_noacct_nocheck+0x17f/0x450
[<0>] submit_bio_noacct+0x2bc/0x780
[<0>] submit_bio+0x70/0xc0
[<0>] mpage_readahead+0x169/0x1f0
[<0>] blkdev_readahead+0x18/0x30
[<0>] read_pages+0x7c/0x3b0
[<0>] page_cache_ra_unbounded+0x1ab/0x280
[<0>] force_page_cache_ra+0x9e/0x130
[<0>] page_cache_sync_ra+0x3b/0x110
[<0>] filemap_get_pages+0x143/0xa30
[<0>] filemap_read+0xdc/0x4b0
[<0>] blkdev_read_iter+0x75/0x200
[<0>] vfs_read+0x272/0x460
[<0>] ksys_read+0x7a/0x170
[<0>] __x64_sys_read+0x1c/0x30
[<0>] do_syscall_64+0xc6/0x230
[<0>] entry_SYSCALL_64_after_hwframe+0x6c/0x74

This is because reshape can't make progress.

For md/raid, the problem doesn't exist because register new sync_thread
doesn't rely on the IO to be done any more:

1) If array is read-only, it can switch to read-write by ioctl/sysfs;
2) md/raid never set MD_RECOVERY_WAIT;
3) If MD_RECOVERY_FROZEN is set, mddev_suspend() doesn't hold
   'reconfig_mutex', hence it can be cleared and reshape can continue by
   sysfs api 'sync_action'.

However, I'm not sure yet how to avoid the problem in dm-raid yet. This
patch on the one hand make sure raid_message() can't change
sync_thread() through raid_message() after presuspend(), on the other
hand detect the above 3 cases before wait for IO do be done in
dm_suspend(), and let dm-raid requeue those IO.

Cc: stable@vger.kernel.org # v6.7+
Signed-off-by: Yu Kuai 
Signed-off-by: Xiao Ni 
Acked-by: Mike Snitzer 
Signed-off-by: Song Liu 
Link: https://lore.kernel.org/r/20240305072306.2562024-9-yukuai1@huaweicloud.com

dm-raid: really frozen sync_thread during suspend

2024-03-05T20:53:32+00:00

1) commit f52f5c71f3d4 ("md: fix stopping sync thread") remove
   MD_RECOVERY_FROZEN from __md_stop_writes() and doesn't realize that
   dm-raid relies on __md_stop_writes() to frozen sync_thread
   indirectly. Fix this problem by adding MD_RECOVERY_FROZEN in
   md_stop_writes(), and since stop_sync_thread() is only used for
   dm-raid in this case, also move stop_sync_thread() to
   md_stop_writes().
2) The flag MD_RECOVERY_FROZEN doesn't mean that sync thread is frozen,
   it only prevent new sync_thread to start, and it can't stop the
   running sync thread; In order to frozen sync_thread, after seting the
   flag, stop_sync_thread() should be used.
3) The flag MD_RECOVERY_FROZEN doesn't mean that writes are stopped, use
   it as condition for md_stop_writes() in raid_postsuspend() doesn't
   look correct. Consider that reentrant stop_sync_thread() do nothing,
   always call md_stop_writes() in raid_postsuspend().
4) raid_message can set/clear the flag MD_RECOVERY_FROZEN at anytime,
   and if MD_RECOVERY_FROZEN is cleared while the array is suspended,
   new sync_thread can start unexpected. Fix this by disallow
   raid_message() to change sync_thread status during suspend.

Note that after commit f52f5c71f3d4 ("md: fix stopping sync thread"), the
test shell/lvconvert-raid-reshape.sh start to hang in stop_sync_thread(),
and with previous fixes, the test won't hang there anymore, however, the
test will still fail and complain that ext4 is corrupted. And with this
patch, the test won't hang due to stop_sync_thread() or fail due to ext4
is corrupted anymore. However, there is still a deadlock related to
dm-raid456 that will be fixed in following patches.

Reported-by: Mikulas Patocka 
Closes: https://lore.kernel.org/all/e5e8afe2-e9a8-49a2-5ab0-958d4065c55e@redhat.com/
Fixes: 1af2048a3e87 ("dm raid: fix deadlock caused by premature md_stop_writes()")
Fixes: 9dbd1aa3a81c ("dm raid: add reshaping support to the target")
Fixes: f52f5c71f3d4 ("md: fix stopping sync thread")
Cc: stable@vger.kernel.org # v6.7+
Signed-off-by: Yu Kuai 
Signed-off-by: Xiao Ni 
Acked-by: Mike Snitzer 
Signed-off-by: Song Liu 
Link: https://lore.kernel.org/r/20240305072306.2562024-6-yukuai1@huaweicloud.com