Merge tag 'vfs-7.3-rc1.super' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs

Merge tag 'vfs-7.3-rc1.super' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs

Pull vfs superblock updates from Christian Brauner:

 - Make it possible to share a block device between multiple
   filesystems.

   erofs can mount read-only blob devices shared between many
   superblocks, but because we only tracked a single superblock a
   freeze, thaw, removal or sync on such a device was never propagated
   to all the superblocks using it, and there was no way to find them.

   Add an efficient table to lookup all superblocks using a given block
   device.

 - A bunch of pre-existing fixes fell out of this work:

   A block-device freeze racing a btrfs device change could leave the
   whole filesystem stuck frozen. A bdev_freeze() issued by "dmsetup
   suspend" or an LVM snapshot resolves that holder to freeze the
   filesystem. and bdev_thaw() resolves it again to thaw. A freeze
   landing while btrfs is adding, removing or replacing a device freezes
   the filesystem. The membership change then drops that link. So the
   matching thaw could no longer find the superblock.

   Forbid freezing a device for the duration of a membership change,
   modelled on deny_write_access()/allow_write_access().

* tag 'vfs-7.3-rc1.super' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (24 commits)
  super: fix dying superblock warning messages
  block: reject block device inodes with i_rdev == 0 in lookup_bdev()
  selftests/filesystems: add ustat() coverage
  fs: look up the superblock via the device table in user_get_super()
  super: make fs_holder_ops private
  f2fs: open via dedicated fs bdev helpers
  erofs: open via dedicated fs bdev helpers
  fs: tolerate per-superblock freeze errors on shared devices
  fs: look up superblocks via the device table in fs_holder_ops
  ext4: open via dedicated fs bdev helpers
  btrfs: open via dedicated fs bdev helpers
  xfs: port to fs_bdev_file_open_by_path()
  fs: add dedicated block device open helpers for filesystems
  fs: maintain a global device-to-superblock table
  ocfs2: don't reset s_dev on dismount
  ext4: use anonymous devices for KUnit test superblocks
  fs, block: move blk_mode_t and fop_flags_t into <linux/types.h>
  super: take lock after last reference count
  super: convert s_count to refcount_t s_passive
  btrfs: deny freezing devices undergoing a replace
  ...