Merge tag 'bcachefs-2025-06-04' of git://evilpiepirate.org/bcachefs

Merge tag 'bcachefs-2025-06-04' of git://evilpiepirate.org/bcachefs

Pull more bcachefs updates from Kent Overstreet:
 "More bcachefs updates:

   - More stack usage improvements (~600 bytes)

   - Define CLASS()es for some commonly used types, and convert most
     rcu_read_lock() uses to the new lock guards

   - New introspection:
       - Superblock error counters are now available in sysfs:
         previously, they were only visible with 'show-super', which
         doesn't provide a live view
       - New tracepoint, error_throw(), which is called any time we
         return an error and start to unwind

   - Repair
       - check_fix_ptrs() can now repair btree node roots
       - We can now repair when we've somehow ended up with the journal
         using a superblock bucket

   - Revert some leftovers from the aborted directory i_size feature,
     and add repair code: some userspace programs (e.g. sshfs) were
     getting confused

  It seems in 6.15 there's a bug where i_nlink on the vfs inode has been
  getting incorrectly set to 0, with some unfortunate results;
  list_journal analysis showed bch2_inode_rm() being called (by
  bch2_evict_inode()) when it clearly should not have been.

   - bch2_inode_rm() now runs "should we be deleting this inode?" checks
     that were previously only run when deleting unlinked inodes in
     recovery

   - check_subvol() was treating a dangling subvol (pointing to a
     missing root inode) like a dangling dirent, and deleting it. This
     was the really unfortunate one: check_subvol() will now recreate
     the root inode if necessary

  This took longer to debug than it should have, and we lost several
  filesystems unnecessarily, because users have been ignoring the
  release notes and blindly running 'fsck -y'. Debugging required
  reconstructing what happened through analyzing the journal, when
  ideally someone would have noticed 'hey, fsck is asking me if I want
  to repair this: it usually doesn't, maybe I should run this in dry run
  mode and check what's going on?'

  As a reminder, fsck errors are being marked as autofix once we've
  verified, in real world usage, that they're working correctly; blindly
  running 'fsck -y' on an experimental filesystem is playing with fire

  Up to this incident we've had an excellent track record of not losing
  data, so let's try to learn from this one

  This is a community effort, I wouldn't be able to get this done
  without the help of all the people QAing and providing excellent bug
  reports and feedback based on real world usage. But please don't
  ignore advice and expect me to pick up the pieces

  If an error isn't marked as autofix, and it /is/ happening in the
  wild, that's also something I need to know about so we can check it
  out and add it to the autofix list if repair looks good. I haven't
  been getting those reports, and I should be; since we don't have any
  sort of telemetry yet I am absolutely dependent on user reports

  Now I'll be spending the weekend working on new repair code to see if
  I can get a filesystem back for a user who didn't have backups"

* tag 'bcachefs-2025-06-04' of git://evilpiepirate.org/bcachefs: (69 commits)
  bcachefs: add cond_resched() to handle_overwrites()
  bcachefs: Make journal read log message a bit quieter
  bcachefs: Fix subvol to missing root repair
  bcachefs: Run may_delete_deleted_inode() checks in bch2_inode_rm()
  bcachefs: delete dead code from may_delete_deleted_inode()
  bcachefs: Add flags to subvolume_to_text()
  bcachefs: Fix oops in btree_node_seq_matches()
  bcachefs: Fix dirent_casefold_mismatch repair
  bcachefs: Fix bch2_fsck_rename_dirent() for casefold
  bcachefs: Redo bch2_dirent_init_name()
  bcachefs: Fix -Wc23-extensions in bch2_check_dirents()
  bcachefs: Run check_dirents second time if required
  bcachefs: Run snapshot deletion out of system_long_wq
  bcachefs: Make check_key_has_snapshot safer
  bcachefs: BCH_RECOVERY_PASS_NO_RATELIMIT
  bcachefs: bch2_require_recovery_pass()
  bcachefs: bch_err_throw()
  bcachefs: Repair code for directory i_size
  bcachefs: Kill un-reverted directory i_size code
  bcachefs: Delete redundant fsck_err()
  ...