- endianness fixes
 - mark some things static
 - fix a few __percpu annotations
 - fix silent enum conversions
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

This changes bch_sb_field_ops lookup to match how bkey_ops now works;
for an unknown field type we return an empty ops struct.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

This adds a new helper for lookups bkey_ops for a given key type, which
returns a null bkey_ops for unknown key types; various bkey_ops users
are tweaked as well to handle unknown key types.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

We need to allow filesystems with metadata from newer versions to be
mountable and usable by older versions.

This patch enables us to roll out new btrees without a new major version
number; we can now handle btree roots for unknown btree types.

The unknown btree roots will be retained, and fsck (including
backpointers) will check them, the same as other btree types.

We add a dynamic array for the extra, unknown btree roots, in addition
to the fixed size btree root array, and add new helpers for looking up
btree roots.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

A crash immediately after device removal can result in an
unmountable filesystem due to recovery failure. The following
command reliably reproduces on a multi-device fs:

  bcachefs device remove <dev> && xfs_io -xc shutdown <mnt>

The post-crash mount fails with an error similar to the following,
reported by fsck:

  invalid journal entry dev_usage at offset 7994/8034 seq 12: bad dev, fixing

This refers to a device usage entry in the journal that refers to
the index of the just removed device. Recovery considers this an
invalid entry and fails to proceed.

Device usage entries are added to journal buffer writes via
bch_journal_write() -> bch2_journal_super_entries_add_common(),
which means any journal buffer write has content that refers to
member devices at the time of the journal write.

The device remove sequence already removes metadata references to
the device being removed. It then flushes any pins that refer to the
device, clears replica entries, removes the in-memory device object
and lastly updates the superblock to reflect that the device is no
longer present. The problem is that any journal writes that occur
during this sequence will include a dev usage entry so long as the
device is present. To avoid this problem, we can flush the journal
once more after the device entry is removed from the in-core
structures, but before the superblock is updated to fully remove the
device on-disk.
Signed-off-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

A simple device evacuate, remove, add test loop with concurrent
shutdowns occasionally reproduces a problem where the filesystem
fails to mount. The mount failure occurs because the filesystem was
uncleanly shut down, yet no member device is marked for journal data
in the superblock. An fsck detects the problem, restores the mark
and allows the mount to proceed without further consistency issues.

The reason for the lack of journal data marks is the gc mechanism
invoked via bch2_journal_flush_device_pins() runs while the journal
happens to be empty. This results in garbage collection of all journal
replicas entries. Once the updated replicas table is written to the
superblock, the filesystem is put in a transiently unrecoverable state
until further journal data is written, because journal recovery expects
to find at least one marked journal device whenever the filesystem is
not otherwise marked clean (i.e. as on clean unmount).

To fix this problem, update the journal replicas gc algorithm to always
mark currently active journal replicas entries by writing to the
journal. This ensures that only entries for devices that are no longer
used for journaling are garbage collected, not just those that don't
happen to currently hold journal data. This preserves the journal
recovery invariant above and avoids putting the fs into a transiently
unrecoverable state.
Signed-off-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

This adds a new helper for checking if an on-disk version is compatible
with the running version of bcachefs - prep work for introducing
major:minor version numbers.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

Add a new helper for printing out metadata versions in a standard
format.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

Now that we have journal watermarks and alloc watermarks unified,
BTREE_INSERT_USE_RESERVE is redundant and can be deleted.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

This fixes a null ptr deref in bch2_free_pending_node_rewrites() when
the list head wasn't initialized.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

This unifies JOURNAL_WATERMARK with BCH_WATERMARK; we're working towards
specifying watermarks once in the transaction commit path.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

Add another watermark for journal reclaim - this is needed for the next
patches, that unify BCH_WATERMARK with JOURNAL_WATERMARK.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

This adds the extent entry for extents that rebalance needs to do
something with.

We're adding this ahead of the main rebalance_work patchset, because
adding new extent entries can't be done in a forwards-compatible way.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

We now have 20 bits for the btree ID in the on disk format - sufficient
for 1 million distinct btrees.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

Error messages should include the error code, when available.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

Some refactoring, prep work for algorithm improvements related to
snapshots.

we need to add a bitmap to the list of inodes for "seen this snapshot";
for this bitmap to correctly be available, we'll need to gather the list
of inodes first, and later look up the inode for a given snapshot.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

We were forgetting to exit a printbuf - whoops.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

Fixes https://lore.kernel.org/linux-bcachefs/784c3e6a-75bd-e6ca-535a-43b3e1daf643@kernel.dk/T/#mbf7caf005f960018eba23b58795d06c06c947411Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

bch2_bkey_make_mut() now takes the bkey_s_c by reference and points it
at the new, mutable key.

This helps in some fsck paths that may have multiple repair operations
on the same key.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

Excessive inlining may (on some versions of gcc?) cause excessive stack
usage; this turns off some inlining in bch2_check_alloc_info.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

A few fsck paths weren't using BTREE_UPDATE_INTERNAL_SNAPSHOT_NODE -
oops.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

We now print out the full previous extent we overlapping with, to aid in
debugging and searching through the journal.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

This is prep work for consolidating with JOURNAL_WATERMARK.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

When we return errors outside of bcachefs, we need to return a standard
error code - fix this for BCH_ERR_fsck.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

bch2_bucket_backpointer_mod() doesn't need to update the alloc key, we
can exit the alloc iter earlier.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

Similar to previous fixes, we can't incur page faults while holding
btree locks.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

dir_emit() can fault (taking mmap_lock); thus we can't be holding btree
locks.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

Add two new helpers for printing error messages with __func__ and
bch2_err_str():
 - bch_err_fn
 - bch_err_msg

Also kill the old error strings in the recovery path, which were causing
us to incorrectly report memory allocation failures - they're not needed
anymore.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

As with the previous patch, we generally can't hold btree locks while
copying to userspace, as that may incur a page fault and require
mmap_lock.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

We can't be holding btree_trans_lock while copying to user space, which
might incur a page fault. To fix this, convert it to a seqmutex so we
can unlock/relock.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

This fixes a deadlock:

01305 WARNING: possible circular locking dependency detected
01305 6.3.0-ktest-gf4de9bee61af #5305 Tainted: G        W
01305 ------------------------------------------------------
01305 cat/14658 is trying to acquire lock:
01305 ffffffc00982f460 (fs_reclaim){+.+.}-{0:0}, at: __kmem_cache_alloc_node+0x48/0x278
01305
01305 but task is already holding lock:
01305 ffffff8011aaf040 (&lock->wait_lock){+.+.}-{2:2}, at: bch2_check_for_deadlock+0x4b8/0xa58
01305
01305 which lock already depends on the new lock.
01305
01305
01305 the existing dependency chain (in reverse order) is:
01305
01305 -> #2 (&lock->wait_lock){+.+.}-{2:2}:
01305        _raw_spin_lock+0x54/0x70
01305        __six_lock_wakeup+0x40/0x1b0
01305        six_unlock_ip+0xe8/0x248
01305        bch2_btree_key_cache_scan+0x720/0x940
01305        shrink_slab.constprop.0+0x284/0x770
01305        shrink_node+0x390/0x828
01305        balance_pgdat+0x390/0x6d0
01305        kswapd+0x2e4/0x718
01305        kthread+0x184/0x1a8
01305        ret_from_fork+0x10/0x20
01305
01305 -> #1 (&c->lock#2){+.+.}-{3:3}:
01305        __mutex_lock+0x104/0x14a0
01305        mutex_lock_nested+0x30/0x40
01305        bch2_btree_key_cache_scan+0x5c/0x940
01305        shrink_slab.constprop.0+0x284/0x770
01305        shrink_node+0x390/0x828
01305        balance_pgdat+0x390/0x6d0
01305        kswapd+0x2e4/0x718
01305        kthread+0x184/0x1a8
01305        ret_from_fork+0x10/0x20
01305
01305 -> #0 (fs_reclaim){+.+.}-{0:0}:
01305        __lock_acquire+0x19d0/0x2930
01305        lock_acquire+0x1dc/0x458
01305        fs_reclaim_acquire+0x9c/0xe0
01305        __kmem_cache_alloc_node+0x48/0x278
01305        __kmalloc_node_track_caller+0x5c/0x278
01305        krealloc+0x94/0x180
01305        bch2_printbuf_make_room.part.0+0xac/0x118
01305        bch2_prt_printf+0x150/0x1e8
01305        bch2_btree_bkey_cached_common_to_text+0x170/0x298
01305        bch2_btree_trans_to_text+0x244/0x348
01305        print_cycle+0x7c/0xb0
01305        break_cycle+0x254/0x528
01305        bch2_check_for_deadlock+0x59c/0xa58
01305        bch2_btree_deadlock_read+0x174/0x200
01305        full_proxy_read+0x94/0xf0
01305        vfs_read+0x15c/0x3a8
01305        ksys_read+0xb8/0x148
01305        __arm64_sys_read+0x48/0x60
01305        invoke_syscall.constprop.0+0x64/0x138
01305        do_el0_svc+0x84/0x138
01305        el0_svc+0x34/0x80
01305        el0t_64_sync_handler+0xb0/0xb8
01305        el0t_64_sync+0x14c/0x150
01305
01305 other info that might help us debug this:
01305
01305 Chain exists of:
01305   fs_reclaim --> &c->lock#2 --> &lock->wait_lock
01305
01305  Possible unsafe locking scenario:
01305
01305        CPU0                    CPU1
01305        ----                    ----
01305   lock(&lock->wait_lock);
01305                                lock(&c->lock#2);
01305                                lock(&lock->wait_lock);
01305   lock(fs_reclaim);
01305
01305  *** DEADLOCK ***
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

We weren't correctly checking the freespace btree - it's an extents
btree, which means we need to iterate over each bucket in a freespace
extent.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

This fixes a spurious assert in the btree node read path.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

The calculation for number of nodes to allocate in
bch2_btree_update_start() was incorrect - this fixes a BUG_ON() on the
small nodes test.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

This adds a new helper for getting a pointer's durability irrespective
of the device state, and uses it in the the data update path.

This fixes a bug where we do a data update but request 0 replicas to be
allocated, because the replica being rewritten is on a device marked as
failed.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>