We want to protect concurrent updates of ovl inode size and mtime
(i.e. ovl_copyattr()) from aio completion context.

Punt write aio completion to a workqueue so that we can protect
ovl_copyattr() with a spinlock.

Export sb_init_dio_done_wq(), so that overlayfs can use its own
dio workqueue to punt aio completions.
Suggested-by: Jens Axboe <axboe@kernel.dk>
Link: https://lore.kernel.org/r/8620dfd3-372d-4ae0-aa3f-2fe97dda1bca@kernel.dk/Signed-off-by: Amir Goldstein <amir73il@gmail.com>

If ovl file is opened O_APPEND, the underlying realfile is also
opened O_APPEND, so it makes sense to propagate the IOCB_APPEND flags
on sync writes to realfile, just as we do with aio writes.

Effectively, because sync ovl writes are protected by inode lock,
this change only makes a difference if the realfile is written to (size
extending writes) from underneath overlayfs.  The behavior in this case
is undefined, so it is ok if we change the behavior (to fail the ovl
IOCB_APPEND write).
Signed-off-by: Amir Goldstein <amir73il@gmail.com>

Overlayfs implements its own function to translate iocb flags into rw
flags, so that they can be passed into another vfs call.

With commit ce71bfea ("fs: align IOCB_* flags with RWF_* flags")
Jens created a 1:1 matching between the iocb flags and rw flags,
simplifying the conversion.
Signed-off-by: Alessio Balsini <balsini@android.com>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>

Pull vfs inode time accessor updates from Christian Brauner:
 "This finishes the conversion of all inode time fields to accessor
  functions as discussed on list. Changing timestamps manually as we
  used to do before is error prone. Using accessors function makes this
  robust.

  It does not contain the switch of the time fields to discrete 64 bit
  integers to replace struct timespec and free up space in struct inode.
  But after this, the switch can be trivially made and the patch should
  only affect the vfs if we decide to do it"

* tag 'vfs-6.7.ctime' of gitolite.kernel.org:pub/scm/linux/kernel/git/vfs/vfs: (86 commits)
  fs: rename inode i_atime and i_mtime fields
  security: convert to new timestamp accessors
  selinux: convert to new timestamp accessors
  apparmor: convert to new timestamp accessors
  sunrpc: convert to new timestamp accessors
  mm: convert to new timestamp accessors
  bpf: convert to new timestamp accessors
  ipc: convert to new timestamp accessors
  linux: convert to new timestamp accessors
  zonefs: convert to new timestamp accessors
  xfs: convert to new timestamp accessors
  vboxsf: convert to new timestamp accessors
  ufs: convert to new timestamp accessors
  udf: convert to new timestamp accessors
  ubifs: convert to new timestamp accessors
  tracefs: convert to new timestamp accessors
  sysv: convert to new timestamp accessors
  squashfs: convert to new timestamp accessors
  server: convert to new timestamp accessors
  client: convert to new timestamp accessors
  ...

Pull vfs xattr updates from Christian Brauner:
 "The 's_xattr' field of 'struct super_block' currently requires a
  mutable table of 'struct xattr_handler' entries (although each handler
  itself is const). However, no code in vfs actually modifies the
  tables.

  This changes the type of 's_xattr' to allow const tables, and modifies
  existing file systems to move their tables to .rodata. This is
  desirable because these tables contain entries with function pointers
  in them; moving them to .rodata makes it considerably less likely to
  be modified accidentally or maliciously at runtime"

* tag 'vfs-6.7.xattr' of gitolite.kernel.org:pub/scm/linux/kernel/git/vfs/vfs: (30 commits)
  const_structs.checkpatch: add xattr_handler
  net: move sockfs_xattr_handlers to .rodata
  shmem: move shmem_xattr_handlers to .rodata
  overlayfs: move xattr tables to .rodata
  xfs: move xfs_xattr_handlers to .rodata
  ubifs: move ubifs_xattr_handlers to .rodata
  squashfs: move squashfs_xattr_handlers to .rodata
  smb: move cifs_xattr_handlers to .rodata
  reiserfs: move reiserfs_xattr_handlers to .rodata
  orangefs: move orangefs_xattr_handlers to .rodata
  ocfs2: move ocfs2_xattr_handlers and ocfs2_xattr_handler_map to .rodata
  ntfs3: move ntfs_xattr_handlers to .rodata
  nfs: move nfs4_xattr_handlers to .rodata
  kernfs: move kernfs_xattr_handlers to .rodata
  jfs: move jfs_xattr_handlers to .rodata
  jffs2: move jffs2_xattr_handlers to .rodata
  hfsplus: move hfsplus_xattr_handlers to .rodata
  hfs: move hfs_xattr_handlers to .rodata
  gfs2: move gfs2_xattr_handlers_max to .rodata
  fuse: move fuse_xattr_handlers to .rodata
  ...

Pull iov_iter updates from Christian Brauner:
 "This contain's David's iov_iter cleanup work to convert the iov_iter
  iteration macros to inline functions:

   - Remove last_offset from iov_iter as it was only used by ITER_PIPE

   - Add a __user tag on copy_mc_to_user()'s dst argument on x86 to
     match that on powerpc and get rid of a sparse warning

   - Convert iter->user_backed to user_backed_iter() in the sound PCM
     driver

   - Convert iter->user_backed to user_backed_iter() in a couple of
     infiniband drivers

   - Renumber the type enum so that the ITER_* constants match the order
     in iterate_and_advance*()

   - Since the preceding patch puts UBUF and IOVEC at 0 and 1, change
     user_backed_iter() to just use the type value and get rid of the
     extra flag

   - Convert the iov_iter iteration macros to always-inline functions to
     make the code easier to follow. It uses function pointers, but they
     get optimised away

   - Move the check for ->copy_mc to _copy_from_iter() and
     copy_page_from_iter_atomic() rather than in memcpy_from_iter_mc()
     where it gets repeated for every segment. Instead, we check once
     and invoke a side function that can use iterate_bvec() rather than
     iterate_and_advance() and supply a different step function

   - Move the copy-and-csum code to net/ where it can be in proximity
     with the code that uses it

   - Fold memcpy_and_csum() in to its two users

   - Move csum_and_copy_from_iter_full() out of line and merge in
     csum_and_copy_from_iter() since the former is the only caller of
     the latter

   - Move hash_and_copy_to_iter() to net/ where it can be with its only
     caller"

* tag 'vfs-6.7.iov_iter' of gitolite.kernel.org:pub/scm/linux/kernel/git/vfs/vfs:
  iov_iter, net: Move hash_and_copy_to_iter() to net/
  iov_iter, net: Merge csum_and_copy_from_iter{,_full}() together
  iov_iter, net: Fold in csum_and_memcpy()
  iov_iter, net: Move csum_and_copy_to/from_iter() to net/
  iov_iter: Don't deal with iter->copy_mc in memcpy_from_iter_mc()
  iov_iter: Convert iterate*() to inline funcs
  iov_iter: Derive user-backedness from the iterator type
  iov_iter: Renumber ITER_* constants
  infiniband: Use user_backed_iter() to see if iterator is UBUF/IOVEC
  sound: Fix snd_pcm_readv()/writev() to use iov access functions
  iov_iter, x86: Be consistent about the __user tag on copy_mc_to_user()
  iov_iter: Remove last_offset from iov_iter as it was for ITER_PIPE

Pull misc vfs updates from Christian Brauner:
 "This contains the usual miscellaneous features, cleanups, and fixes
  for vfs and individual fses.

  Features:

   - Rename and export helpers that get write access to a mount. They
     are used in overlayfs to get write access to the upper mount.

   - Print the pretty name of the root device on boot failure. This
     helps in scenarios where we would usually only print
     "unknown-block(1,2)".

   - Add an internal SB_I_NOUMASK flag. This is another part in the
     endless POSIX ACL saga in a way.

     When POSIX ACLs are enabled via SB_POSIXACL the vfs cannot strip
     the umask because if the relevant inode has POSIX ACLs set it might
     take the umask from there. But if the inode doesn't have any POSIX
     ACLs set then we apply the umask in the filesytem itself. So we end
     up with:

      (1) no SB_POSIXACL -> strip umask in vfs
      (2) SB_POSIXACL    -> strip umask in filesystem

     The umask semantics associated with SB_POSIXACL allowed filesystems
     that don't even support POSIX ACLs at all to raise SB_POSIXACL
     purely to avoid umask stripping. That specifically means NFS v4 and
     Overlayfs. NFS v4 does it because it delegates this to the server
     and Overlayfs because it needs to delegate umask stripping to the
     upper filesystem, i.e., the filesystem used as the writable layer.

     This went so far that SB_POSIXACL is raised eve on kernels that
     don't even have POSIX ACL support at all.

     Stop this blatant abuse and add SB_I_NOUMASK which is an internal
     superblock flag that filesystems can raise to opt out of umask
     handling. That should really only be the two mentioned above. It's
     not that we want any filesystems to do this. Ideally we have all
     umask handling always in the vfs.

   - Make overlayfs use SB_I_NOUMASK too.

   - Now that we have SB_I_NOUMASK, stop checking for SB_POSIXACL in
     IS_POSIXACL() if the kernel doesn't have support for it. This is a
     very old patch but it's only possible to do this now with the wider
     cleanup that was done.

   - Follow-up work on fake path handling from last cycle. Citing mostly
     from Amir:

     When overlayfs was first merged, overlayfs files of regular files
     and directories, the ones that are installed in file table, had a
     "fake" path, namely, f_path is the overlayfs path and f_inode is
     the "real" inode on the underlying filesystem.

     In v6.5, we took another small step by introducing of the
     backing_file container and the file_real_path() helper. This change
     allowed vfs and filesystem code to get the "real" path of an
     overlayfs backing file. With this change, we were able to make
     fsnotify work correctly and report events on the "real" filesystem
     objects that were accessed via overlayfs.

     This method works fine, but it still leaves the vfs vulnerable to
     new code that is not aware of files with fake path. A recent
     example is commit db1d1e8b ("IMA: use vfs_getattr_nosec to get
     the i_version"). This commit uses direct referencing to f_path in
     IMA code that otherwise uses file_inode() and file_dentry() to
     reference the filesystem objects that it is measuring.

     This contains work to switch things around: instead of having
     filesystem code opt-in to get the "real" path, have generic code
     opt-in for the "fake" path in the few places that it is needed.

     Is it far more likely that new filesystems code that does not use
     the file_dentry() and file_real_path() helpers will end up causing
     crashes or averting LSM/audit rules if we keep the "fake" path
     exposed by default.

     This change already makes file_dentry() moot, but for now we did
     not change this helper just added a WARN_ON() in ovl_d_real() to
     catch if we have made any wrong assumptions.

     After the dust settles on this change, we can make file_dentry() a
     plain accessor and we can drop the inode argument to ->d_real().

   - Switch struct file to SLAB_TYPESAFE_BY_RCU. This looks like a small
     change but it really isn't and I would like to see everyone on
     their tippie toes for any possible bugs from this work.

     Essentially we've been doing most of what SLAB_TYPESAFE_BY_RCU for
     files since a very long time because of the nasty interactions
     between the SCM_RIGHTS file descriptor garbage collection. So
     extending it makes a lot of sense but it is a subtle change. There
     are almost no places that fiddle with file rcu semantics directly
     and the ones that did mess around with struct file internal under
     rcu have been made to stop doing that because it really was always
     dodgy.

     I forgot to put in the link tag for this change and the discussion
     in the commit so adding it into the merge message:

       https://lore.kernel.org/r/20230926162228.68666-1-mjguzik@gmail.com

  Cleanups:

   - Various smaller pipe cleanups including the removal of a spin lock
     that was only used to protect against writes without pipe_lock()
     from O_NOTIFICATION_PIPE aka watch queues. As that was never
     implemented remove the additional locking from pipe_write().

   - Annotate struct watch_filter with the new __counted_by attribute.

   - Clarify do_unlinkat() cleanup so that it doesn't look like an extra
     iput() is done that would cause issues.

   - Simplify file cleanup when the file has never been opened.

   - Use module helper instead of open-coding it.

   - Predict error unlikely for stale retry.

   - Use WRITE_ONCE() for mount expiry field instead of just commenting
     that one hopes the compiler doesn't get smart.

  Fixes:

   - Fix readahead on block devices.

   - Fix writeback when layztime is enabled and inodes whose timestamp
     is the only thing that changed reside on wb->b_dirty_time. This
     caused excessively large zombie memory cgroup when lazytime was
     enabled as such inodes weren't handled fast enough.

   - Convert BUG_ON() to WARN_ON_ONCE() in open_last_lookups()"

* tag 'vfs-6.7.misc' of gitolite.kernel.org:pub/scm/linux/kernel/git/vfs/vfs: (26 commits)
  file, i915: fix file reference for mmap_singleton()
  vfs: Convert BUG_ON to WARN_ON_ONCE in open_last_lookups
  writeback, cgroup: switch inodes with dirty timestamps to release dying cgwbs
  chardev: Simplify usage of try_module_get()
  ovl: rely on SB_I_NOUMASK
  fs: fix umask on NFS with CONFIG_FS_POSIX_ACL=n
  fs: store real path instead of fake path in backing file f_path
  fs: create helper file_user_path() for user displayed mapped file path
  fs: get mnt_writers count for an open backing file's real path
  vfs: stop counting on gcc not messing with mnt_expiry_mark if not asked
  vfs: predict the error in retry_estale as unlikely
  backing file: free directly
  vfs: fix readahead(2) on block devices
  io_uring: use files_lookup_fd_locked()
  file: convert to SLAB_TYPESAFE_BY_RCU
  vfs: shave work on failed file open
  fs: simplify misleading code to remove ambiguity regarding ihold()/iput()
  watch_queue: Annotate struct watch_filter with __counted_by
  fs/pipe: use spinlock in pipe_read() only if there is a watch_queue
  fs/pipe: remove unnecessary spinlock from pipe_write()
  ...

Pull autofs mount api updates from Christian Brauner:
 "This ports autofs to the new mount api. The patchset has existed for
  quite a while but never made it upstream. Ian picked it back up.

  This also fixes a bug where fs_param_is_fd() was passed a garbage
  param->dirfd but it expected it to be set to the fd that was used to
  set param->file otherwise result->uint_32 contains nonsense. So make
  sure it's set.

  One less filesystem using the old mount api. We're getting there,
  albeit rather slow. The last remaining major filesystem that hasn't
  converted is btrfs. Patches exist - I even wrote them - but so far
  they haven't made it upstream"

* tag 'vfs-6.7.autofs' of gitolite.kernel.org:pub/scm/linux/kernel/git/vfs/vfs:
  autofs: fix add autofs_parse_fd()
  fsconfig: ensure that dirfd is set to aux
  autofs: fix protocol sub version setting
  autofs: convert autofs to use the new mount api
  autofs: validate protocol version
  autofs: refactor parse_options()
  autofs: reformat 0pt enum declaration
  autofs: refactor super block info init
  autofs: add autofs_parse_fd()
  autofs: refactor autofs_prepare_pipe()

Pull vfs superblock updates from Christian Brauner:
 "This contains the work to make block device opening functions return a
  struct bdev_handle instead of just a struct block_device. The same
  struct bdev_handle is then also passed to block device closing
  functions.

  This allows us to propagate context from opening to closing a block
  device without having to modify all users everytime.

  Sidenote, in the future we might even want to try and have block
  device opening functions return a struct file directly but that's a
  series on top of this.

  These are further preparatory changes to be able to count writable
  opens and blocking writes to mounted block devices. That's a separate
  piece of work for next cycle and for that we absolutely need the
  changes to btrfs that have been quietly dropped somehow.

  Originally the series contained a patch that removed the old
  blkdev_*() helpers. But since this would've caused needles churn in
  -next for bcachefs we ended up delaying it.

  The second piece of work addresses one of the major annoyances about
  the work last cycle, namely that we required dropping s_umount
  whenever we used the superblock and fs_holder_ops for a block device.

  The reason for that requirement had been that in some codepaths
  s_umount could've been taken under disk->open_mutex (that's always
  been the case, at least theoretically). For example, on surprise block
  device removal or media change. And opening and closing block devices
  required grabbing disk->open_mutex as well.

  So we did the work and went through the block layer and fixed all
  those places so that s_umount is never taken under disk->open_mutex.
  This means no more brittle games where we yield and reacquire s_umount
  during block device opening and closing and no more requirements where
  block devices need to be closed. Filesystems don't need to care about
  this.

  There's a bunch of other follow-up work such as moving block device
  freezing and thawing to holder operations which makes it work for all
  block devices and not just the main block device just as we did for
  surprise removal. But that is for next cycle.

  Tested with fstests for all major fses, blktests, LTP"

* tag 'vfs-6.7.super' of gitolite.kernel.org:pub/scm/linux/kernel/git/vfs/vfs: (37 commits)
  porting: update locking requirements
  fs: assert that open_mutex isn't held over holder ops
  block: assert that we're not holding open_mutex over blk_report_disk_dead
  block: move bdev_mark_dead out of disk_check_media_change
  block: WARN_ON_ONCE() when we remove active partitions
  block: simplify bdev_del_partition()
  fs: Avoid grabbing sb->s_umount under bdev->bd_holder_lock
  jfs: fix log->bdev_handle null ptr deref in lbmStartIO
  bcache: Fixup error handling in register_cache()
  xfs: Convert to bdev_open_by_path()
  reiserfs: Convert to bdev_open_by_dev/path()
  ocfs2: Convert to use bdev_open_by_dev()
  nfs/blocklayout: Convert to use bdev_open_by_dev/path()
  jfs: Convert to bdev_open_by_dev()
  f2fs: Convert to bdev_open_by_dev/path()
  ext4: Convert to bdev_open_by_dev()
  erofs: Convert to use bdev_open_by_path()
  btrfs: Convert to bdev_open_by_path()
  fs: Convert to bdev_open_by_dev()
  mm/swap: Convert to use bdev_open_by_dev()
  ...

Pull misc x86 fixes from Ingo Molnar:

 - Fix a possible CPU hotplug deadlock bug caused by the new TSC
   synchronization code

 - Fix a legacy PIC discovery bug that results in device troubles on
   affected systems, such as non-working keybards, etc

 - Add a new Intel CPU model number to <asm/intel-family.h>

* tag 'x86-urgent-2023-10-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/tsc: Defer marking TSC unstable to a worker
  x86/i8259: Skip probing when ACPI/MADT advertises PCAT compatibility
  x86/cpu: Add model number for Intel Arrow Lake mobile processor

Pull irq fix from Ingo Molnar:
 "Restore unintentionally lost quirk settings in the GIC irqchip driver,
  which broke certain devices"

* tag 'irq-urgent-2023-10-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  irqchip/gic-v3-its: Don't override quirk settings with default values

Pull perf event fix from Ingo Molnar:
 "Fix a potential NULL dereference bug"

* tag 'perf-urgent-2023-10-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf/core: Fix potential NULL deref

Merge tag 'probes-fixes-v6.6-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

Pull probes fixes from Masami Hiramatsu:

 - tracing/kprobes: Fix kernel-doc warnings for the variable length
   arguments

 - tracing/kprobes: Fix to count the symbols in modules even if the
   module name is not specified so that user can probe the symbols in
   the modules without module name

* tag 'probes-fixes-v6.6-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  tracing/kprobes: Fix symbol counting logic by looking at modules as well
  tracing/kprobes: Fix the description of variable length arguments

Pull dma-mapping fix from Christoph Hellwig:

 - reduce the initialy dynamic swiotlb size to remove an annoying but
   harmless warning from the page allocator (Petr Tesarik)

* tag 'dma-mapping-6.6-2023-10-28' of git://git.infradead.org/users/hch/dma-mapping:
  swiotlb: do not try to allocate a TLB bigger than MAX_ORDER pages

Pull char/misc driver fixes from Greg KH:
 "Here are some very small driver fixes for 6.6-final that have shown up
  in the past two weeks. Included in here are:

   - tiny fastrpc bugfixes for reported errors

   - nvmem register fixes

   - iio driver fixes for some reported problems

   - fpga test fix

   - MAINTAINERS file update for fpga

  All of these have been in linux-next this week with no reported
  problems"

* tag 'char-misc-6.6-final' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc:
  fpga: Fix memory leak for fpga_region_test_class_find()
  fpga: m10bmc-sec: Change contact for secure update driver
  fpga: disable KUnit test suites when module support is enabled
  iio: afe: rescale: Accept only offset channels
  nvmem: imx: correct nregs for i.MX6ULL
  nvmem: imx: correct nregs for i.MX6UL
  nvmem: imx: correct nregs for i.MX6SLL
  misc: fastrpc: Unmap only if buffer is unmapped from DSP
  misc: fastrpc: Clean buffers on remote invocation failures
  misc: fastrpc: Free DMA handles for RPC calls with no arguments
  misc: fastrpc: Reset metadata buffer to avoid incorrect free
  iio: exynos-adc: request second interupt only when touchscreen mode is used
  iio: adc: xilinx-xadc: Correct temperature offset/scale for UltraScale
  iio: adc: xilinx-xadc: Don't clobber preset voltage/temperature thresholds
  dt-bindings: iio: add missing reset-gpios constrain

Pull i2c fixes from Wolfram Sang:
 "Bugfixes for Axxia when it is a target and for PEC handling of
  stm32f7.

  Plus, fix an OF node leak pattern in the mux subsystem"

* tag 'i2c-for-6.6-rc8' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux:
  i2c: stm32f7: Fix PEC handling in case of SMBUS transfers
  i2c: muxes: i2c-mux-gpmux: Use of_get_i2c_adapter_by_node()
  i2c: muxes: i2c-demux-pinctrl: Use of_get_i2c_adapter_by_node()
  i2c: muxes: i2c-mux-pinctrl: Use of_get_i2c_adapter_by_node()
  i2c: aspeed: Fix i2c bus hang in slave read

Now that s_umount is never taken under open_mutex update the
documentation to say so.

Link: https://lore.kernel.org/r/20231017184823.1383356-1-hch@lst.deSigned-off-by: Christian Brauner <brauner@kernel.org>

With recent block level changes we should never be in a situation where
we hold disk->open_mutex when calling into these helpers. So assert that
in the code.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20231017184823.1383356-6-hch@lst.deReviewed-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Christian Brauner <brauner@kernel.org>

blk_report_disk_dead() has the following major callers:

(1) del_gendisk()
(2) blk_mark_disk_dead()

Since del_gendisk() acquires disk->open_mutex it's clear that all
callers are assumed to be called without disk->open_mutex held.
In turn, blk_report_disk_dead() is called without disk->open_mutex held
in del_gendisk().

All callers of blk_mark_disk_dead() call it without disk->open_mutex as
well.

Ensure that it is clear that blk_report_disk_dead() is called without
disk->open_mutex on purpose by asserting it and a comment in the code.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20231017184823.1383356-5-hch@lst.deReviewed-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Christian Brauner <brauner@kernel.org>

disk_check_media_change is mostly called from ->open where it makes
little sense to mark the file system on the device as dead, as we
are just opening it.  So instead of calling bdev_mark_dead from
disk_check_media_change move it into the few callers that are not
in an open instance.  This avoid calling into bdev_mark_dead and
thus taking s_umount with open_mutex held.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20231017184823.1383356-4-hch@lst.deReviewed-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Christian Brauner <brauner@kernel.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Christian Brauner <brauner@kernel.org>

The logic for disk->open_partitions is:

blkdev_get_by_*()
-> bdev_is_partition()
   -> blkdev_get_part()
      -> blkdev_get_whole() // bdev_whole->bd_openers++
      -> if (part->bd_openers == 0)
                 disk->open_partitions++
         part->bd_openers

In other words, when we first claim/open a partition we increment
disk->open_partitions and only when all part->bd_openers are closed will
disk->open_partitions be zero. That should mean that
disk->open_partitions is always > 0 as long as there's anyone that
has an open partition.

So the check for disk->open_partitions should mean that we can never
remove an active partition that has a holder and holder ops set. Assert
that in the code. The main disk isn't removed so that check doesn't work
for disk->part0 which is what we want. After all we only care about
partition not about the main disk.

Link: https://lore.kernel.org/r/20231017184823.1383356-3-hch@lst.deReviewed-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Christian Brauner <brauner@kernel.org>

BLKPG_DEL_PARTITION refuses to delete partitions that still have
openers, i.e., that has an elevated @bdev->bd_openers count. If a device
is claimed by setting @bdev->bd_holder and @bdev->bd_holder_ops
@bdev->bd_openers and @bdev->bd_holders are incremented.
@bdev->bd_openers is effectively guaranteed to be >= @bdev->bd_holders.
So as long as @bdev->bd_openers isn't zero we know that this partition
is still in active use and that there might still be @bdev->bd_holder
and @bdev->bd_holder_ops set.

The only current example is @fs_holder_ops for filesystems. But that
means bdev_mark_dead() which calls into
bdev->bd_holder_ops->mark_dead::fs_bdev_mark_dead() is a nop. As long as
there's an elevated @bdev->bd_openers count we can't delete the
partition and if there isn't an elevated @bdev->bd_openers count then
there's no @bdev->bd_holder or @bdev->bd_holder_ops.

So simply open-code what we need to do. This gets rid of one more
instance where we acquire s_umount under @disk->open_mutex.

Link: https://lore.kernel.org/r/20231016-fototermin-umriss-59f1ea6c1fe6@braunerReviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20231017184823.1383356-2-hch@lst.deReviewed-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>

The implementation of bdev holder operations such as fs_bdev_mark_dead()
and fs_bdev_sync() grab sb->s_umount semaphore under
bdev->bd_holder_lock. This is problematic because it leads to
disk->open_mutex -> sb->s_umount lock ordering which is counterintuitive
(usually we grab higher level (e.g. filesystem) locks first and lower
level (e.g. block layer) locks later) and indeed makes lockdep complain
about possible locking cycles whenever we open a block device while
holding sb->s_umount semaphore. Implement a function
bdev_super_lock_shared() which safely transitions from holding
bdev->bd_holder_lock to holding sb->s_umount on alive superblock without
introducing the problematic lock dependency. We use this function
fs_bdev_sync() and fs_bdev_mark_dead().
Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20231018152924.3858-1-jack@suse.cz
Link: https://lore.kernel.org/r/20231017184823.1383356-1-hch@lst.deReviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner <brauner@kernel.org>

When sbi->flag is JFS_NOINTEGRITY in lmLogOpen(), log->bdev_handle can't
be inited, so it value will be NULL.
Therefore, add the "log ->no_integrity=1" judgment in lbmStartIO() to avoid such
problems.

Reported-and-tested-by: syzbot+23bc20037854bb335d59@syzkaller.appspotmail.com
Signed-off-by: Lizhi Xu <lizhi.xu@windriver.com>
Link: https://lore.kernel.org/r/20231009094557.1398920-1-lizhi.xu@windriver.comReviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>

Coverity has noticed that the printing of error message in
register_cache() uses already freed bdev_handle to get to bdev. In fact
the problem has been there even before commit "bcache: Convert to
bdev_open_by_path()" just a bit more subtle one - cache object itself
could have been freed by the time we looked at ca->bdev and we don't
hold any reference to bdev either so even that could in principle go
away (due to device unplug or similar). Fix all these problems by
printing the error message before closing the bdev.

Fixes: dc893f51d24a ("bcache: Convert to bdev_open_by_path()")
Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20231004093757.11560-1-jack@suse.czAsked-by: Coly Li <colyli@suse.de>
Signed-off-by: Christian Brauner <brauner@kernel.org>

Convert xfs to use bdev_open_by_path() and pass the handle around.

CC: "Darrick J. Wong" <djwong@kernel.org>
CC: linux-xfs@vger.kernel.org
Acked-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20230927093442.25915-28-jack@suse.czAcked-by: "Darrick J. Wong" <djwong@kernel.org>
Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>

Convert reiserfs to use bdev_open_by_dev/path() and pass the handle
around.

CC: reiserfs-devel@vger.kernel.org
Acked-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20230927093442.25915-27-jack@suse.czSigned-off-by: Christian Brauner <brauner@kernel.org>

Convert ocfs2 heartbeat code to use bdev_open_by_dev() and pass the
handle around.

CC: Joseph Qi <joseph.qi@linux.alibaba.com>
CC: ocfs2-devel@oss.oracle.com
Acked-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Joseph Qi <joseph.qi@linux.alibaba.com>
Reviewed-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20230927093442.25915-26-jack@suse.czSigned-off-by: Christian Brauner <brauner@kernel.org>

Convert block device handling to use bdev_open_by_dev/path() and pass
the handle around.

CC: linux-nfs@vger.kernel.org
CC: Trond Myklebust <trond.myklebust@hammerspace.com>
CC: Anna Schumaker <anna@kernel.org>
Acked-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20230927093442.25915-25-jack@suse.czSigned-off-by: Christian Brauner <brauner@kernel.org>

Convert jfs to use bdev_open_by_dev() and pass the handle around.

CC: Dave Kleikamp <shaggy@kernel.org>
CC: jfs-discussion@lists.sourceforge.net
Acked-by: Christoph Hellwig <hch@lst.de>
Acked-by: Dave Kleikamp <dave.kleikamp@oracle.com>
Reviewed-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20230927093442.25915-24-jack@suse.czSigned-off-by: Christian Brauner <brauner@kernel.org>

Convert f2fs to use bdev_open_by_dev/path() and pass the handle around.

CC: Jaegeuk Kim <jaegeuk@kernel.org>
CC: Chao Yu <chao@kernel.org>
CC: linux-f2fs-devel@lists.sourceforge.net
Acked-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20230927093442.25915-23-jack@suse.czSigned-off-by: Christian Brauner <brauner@kernel.org>

Convert ext4 to use bdev_open_by_dev() and pass the handle around.

CC: linux-ext4@vger.kernel.org
CC: Ted Tso <tytso@mit.edu>
Acked-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20230927093442.25915-22-jack@suse.czSigned-off-by: Christian Brauner <brauner@kernel.org>

Convert erofs to use bdev_open_by_path() and pass the handle around.

CC: Gao Xiang <xiang@kernel.org>
CC: Chao Yu <chao@kernel.org>
CC: linux-erofs@lists.ozlabs.org
Acked-by: Christoph Hellwig <hch@lst.de>
Acked-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Reviewed-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20230927093442.25915-21-jack@suse.czSigned-off-by: Christian Brauner <brauner@kernel.org>

Convert btrfs to use bdev_open_by_path() and pass the handle around.  We
also drop the holder from struct btrfs_device as it is now not needed
anymore.

CC: David Sterba <dsterba@suse.com>
CC: linux-btrfs@vger.kernel.org
Acked-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20230927093442.25915-20-jack@suse.czSigned-off-by: Christian Brauner <brauner@kernel.org>

Convert mount code to use bdev_open_by_dev() and propagate the handle
around to bdev_release().
Acked-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20230927093442.25915-19-jack@suse.czSigned-off-by: Christian Brauner <brauner@kernel.org>

Convert swapping code to use bdev_open_by_dev() and pass the handle
around.

CC: linux-mm@kvack.org
CC: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Christoph Hellwig <hch@lst.de>
Acked-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20230927093442.25915-18-jack@suse.czSigned-off-by: Christian Brauner <brauner@kernel.org>

snapshot_test argument is now unused in swsusp_close() and
load_image_and_restore(). Drop it

CC: linux-pm@vger.kernel.org
Acked-by: Christoph Hellwig <hch@lst.de>
Acked-by: "Rafael J. Wysocki" <rafael@kernel.org>
Acked-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20230927093442.25915-17-jack@suse.czSigned-off-by: Christian Brauner <brauner@kernel.org>

Convert hibernation code to use bdev_open_by_dev().

CC: linux-pm@vger.kernel.org
Acked-by: Christoph Hellwig <hch@lst.de>
Acked-by: "Rafael J. Wysocki" <rafael@kernel.org>
Acked-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20230927093442.25915-16-jack@suse.czSigned-off-by: Christian Brauner <brauner@kernel.org>

Convert iblock and pscsi drivers to use bdev_open_by_path() and pass the
handle around.

CC: target-devel@vger.kernel.org
CC: linux-scsi@vger.kernel.org
Acked-by: Christoph Hellwig <hch@lst.de>
Acked-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20230927093442.25915-15-jack@suse.czReviewed-by: "Martin K. Petersen" <martin.petersen@oracle.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>