Merge tag 'bcachefs-2024-04-15' of https://evilpiepirate.org/git/bcachefs

Merge tag 'bcachefs-2024-04-15' of https://evilpiepirate.org/git/bcachefs

Pull yet more bcachefs fixes from Kent Overstreet:
 "This gets recovery working again for the affected user I've been
  working with, and I'm still waiting to hear back on other bug reports
  but should fix it for everyone else who's been having issues with
  recovery.

   - Various recovery fixes:

       - fixes for the btree_insert_entry being resized on path
         allocation btree_path array recently became dynamically
         resizable, and btree_insert_entry along with it; this was being
         observed during journal replay, when write buffer btree updates
         don't use the write buffer and instead use the normal btree
         update path

       - multiple fixes for deadlock in recovery when we need to do lots
         of btree node merges; excessive merges were clocking up the
         whole pipeline

       - write buffer path now correctly does btree node merges when
         needed

       - fix failure to go RW when superblock indicates recovery passes
         needed (i.e. to complete an unfinished upgrade)

   - Various unsafety fixes - test case contributed by a user who had
     two drives out of a six drive array write out a whole bunch of
     garbage after power failure

   - New (tiny) on disk format feature: since it appears the btree node
     scan tool will be a more regular thing (crappy hardware, user
     error) - this adds a 64 bit per-device bitmap of regions that have
     ever had btree nodes.

   - A path->should_be_locked fix, from a larger patch series tightening
     up invariants and assertions around btree transaction and path
     locking state.

     This particular fix prevents us from keeping around btree_paths
     that are no longer needed"

* tag 'bcachefs-2024-04-15' of https://evilpiepirate.org/git/bcachefs: (24 commits)
  bcachefs: set_btree_iter_dontneed also clears should_be_locked
  bcachefs: fix error path of __bch2_read_super()
  bcachefs: Check for backpointer bucket_offset >= bucket size
  bcachefs: bch_member.btree_allocated_bitmap
  bcachefs: sysfs internal/trigger_journal_flush
  bcachefs: Fix bch2_btree_node_fill() for !path
  bcachefs: add safety checks in bch2_btree_node_fill()
  bcachefs: Interior known are required to have known key types
  bcachefs: add missing bounds check in __bch2_bkey_val_invalid()
  bcachefs: Fix btree node merging on write buffer btrees
  bcachefs: Disable merges from interior update path
  bcachefs: Run merges at BCH_WATERMARK_btree
  bcachefs: Fix missing write refs in fs fio paths
  bcachefs: Fix deadlock in journal replay
  bcachefs: Go rw if running any explicit recovery passes
  bcachefs: Standardize helpers for printing enum strs with bounds checks
  bcachefs: don't queue btree nodes for rewrites during scan
  bcachefs: fix race in bch2_btree_node_evict()
  bcachefs: fix unsafety in bch2_stripe_to_text()
  bcachefs: fix unsafety in bch2_extent_ptr_to_text()
  ...