When we're called via
trans commit -> btree split -> allocator

We may have already arbitrarily many btree_paths, for the transaction
commit we're trying to do; when this happens, the
btree_trans_too_many_iters() call causes us to livelock.

Since the allocator calls btree_iter_dontneed to release paths as it
iterates, this shouldn't cause any problems.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

Shifting a value by the width of its type or more is undefined.
Signed-off-by: Tavian Barnes <tavianator@tavianator.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

Cc: Waiman Long <longman@redhat.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

We can't have more updates than paths, so btree_path_idx_t is the
correct type to use.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

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

If a btree_trans is in use it's supposed to be passed to fsck_err so
that it can be unlocked if we're waiting on userspace input; but the
btree IO paths do call fsck errors where a btree_trans exists on the
stack but it's not passed through.

But it's ok, because it's unlocked while doing IO.

Fixes: a850bde6 ("bcachefs: fsck_err() may now take a btree_trans")
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

This causes us to go read-only - need an error message saying why.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

Shifting a negative value left is undefined.
Signed-off-by: Tavian Barnes <tavianator@tavianator.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

memcpy's second parameter must not be NULL, even if size is zero.
Signed-off-by: Tavian Barnes <tavianator@tavianator.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

We no longer track individual btree node locks with lockdep, so this
will never be enabled.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

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

perusal of /sys/kernel/debug/bcachefs/*/btree_transaction_stats shows
that the read path has been acculumalating unneeded paths on the reflink
btree, which we don't want.

The solution is to call bch2_trans_begin(), which drops paths not used
on previous loop iteration.

bch2_readahead:
  Max mem used: 0
  Transaction duration:
    count:      194235
                           since mount        recent
    duration of events
      min:                      150 ns
      max:                        9 ms
      total:                    838 ms
      mean:                       4 us          6 us
      stddev:                    34 us          7 us
    time between events
      min:                       10 ns
      max:                       15 h
      mean:                       2 s          12 s
      stddev:                     2 s           3 ms
  Maximum allocated btree paths (193):
    path: idx  2 ref 0:0 P   btree=extents l=0 pos 270943112:392:U32_MAX locks 0
    path: idx  3 ref 1:0   S btree=extents l=0 pos 270943112:24578:U32_MAX locks 1
    path: idx  4 ref 0:0 P   btree=reflink l=0 pos 0:24773509:0 locks 0
    path: idx  5 ref 0:0 P S btree=reflink l=0 pos 0:24773631:0 locks 1
    path: idx  6 ref 0:0 P S btree=reflink l=0 pos 0:24773759:0 locks 1
    path: idx  7 ref 0:0 P S btree=reflink l=0 pos 0:24773887:0 locks 1
    path: idx  8 ref 0:0 P S btree=reflink l=0 pos 0:24774015:0 locks 1
    path: idx  9 ref 0:0 P S btree=reflink l=0 pos 0:24774143:0 locks 1
    path: idx 10 ref 0:0 P S btree=reflink l=0 pos 0:24774271:0 locks 1
<many more reflink paths>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

If label is not set, the Label tag in superblock info show '(none)'.

```
[Before]
Device index:                               0
Label:
Version:                                    1.4: member_seq

[After]
Device index:                               0
Label:                                      (none)
Version:                                    1.4: member_seq
```
Signed-off-by: Hongbo Li <lihongbo22@huawei.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

Unnecessary here, and this broke the rust bindings:

error[E0588]: packed type cannot transitively contain a `#[repr(align)]` type
     --> /build/source/target/release/build/bch_bindgen-9445b24c90aca2a3/out/bcachefs.rs:29025:1
      |
29025 | pub struct bkey_i_inode_v3 {
      | ^^^^^^^^^^^^^^^^^^^^^^^^^^
      |
note: `bch_inode_v3` has a `#[repr(align)]` attribute
     --> /build/source/target/release/build/bch_bindgen-9445b24c90aca2a3/out/bcachefs.rs:8949:1
      |
8949  | pub struct bch_inode_v3 {
      | ^^^^^^^^^^^^^^^^^^^^^^^

error[E0588]: packed type cannot transitively contain a `#[repr(align)]` type
     --> /build/source/target/release/build/bch_bindgen-9445b24c90aca2a3/out/bcachefs.rs:32826:1
      |
32826 | pub struct bkey_inode_buf {
      | ^^^^^^^^^^^^^^^^^^^^^^^^^
      |
note: `bch_inode_v3` has a `#[repr(align)]` attribute
     --> /build/source/target/release/build/bch_bindgen-9445b24c90aca2a3/out/bcachefs.rs:8949:1
      |
8949  | pub struct bch_inode_v3 {
      | ^^^^^^^^^^^^^^^^^^^^^^^
note: `bkey_inode_buf` contains a field of type `bkey_i_inode_v3`
     --> /build/source/target/release/build/bch_bindgen-9445b24c90aca2a3/out/bcachefs.rs:32827:9
      |
32827 |     pub inode: bkey_i_inode_v3,
      |         ^^^^^
note: ...which contains a field of type `bch_inode_v3`
     --> /build/source/target/release/build/bch_bindgen-9445b24c90aca2a3/out/bcachefs.rs:29027:9
      |
29027 |     pub v: bch_inode_v3,
      |         ^
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

highly damaged filesystems, or filesystems that have been damaged and
repair and damaged again, may have sequence numbers we can't fully trust
- which in itself is something we need to debug.

Add a journal_seq fallback so that repair doesn't get stuck.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

This adds lockdep tracking for held btree locks with a single dep_map in
btree_trans, i.e. tracking all held btree locks as one object.

This is more practical and more useful than having lockdep track held
btree locks individually, because
 - we can take more locks than lockdep can track (unbounded, now that we
   have dynamically resizable btree paths)
 - there's no lock ordering between btree locks for lockdep to track (we
   do cycle detection)
 - and this makes it easy to teach lockdep that btree locks are not safe
   to hold while invoking memory reclaim.

The last rule is one that lockdep would never learn, because we only do
trylock() from within shrinkers - but we very much do not want to be
invoking memory reclaim while holding btree node locks.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

Add a new helper to disable lockdep tracking entirely for a given class.

This is needed for bcachefs, which takes too many btree node locks for
lockdep to track. Instead, we have a single lockdep_map for "btree_trans
has any btree nodes locked", which makes more since given that we have
centralized lock management and a cycle detector.

Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Will Deacon <will@kernel.org>
Cc: Waiman Long <longman@redhat.com>
Cc: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

printing the raw values can occasionally be very useful
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

Eliminate possible integer truncation bugs on 32 bit
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

We're not always mounting when we start the filesystem
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

This repurposes the promote path, which already knows how to call
data_update() after a read: we now automatically rewrite bad data when
we get a read error and then successfully retry from a different
replica.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

fsck passes read_only as a mount option, and it's required for
nochanges, which it also uses.

Usually read_only is handled by the VFS, but we need to be able to
handle it too; we just don't want to print it out twice, so mark it as a
hidden option.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

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

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

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

Don't allocate the new bkey_cached until after we've done the btree
lookup; this means we can kill bkey_cached.valid.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

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

This fixes an accounting mismatch for cached data.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

This adds a new helper, bch2_folio_reservation_get_partial(), which
reserves as many blocks as possible and may return partial success.

__bch2_buffered_write() is switched to the new helper - this fixes
fstests generic/275, the write until -ENOSPC test.

generic/230 now fails: this appears to be a test bug, where xfs_io isn't
looping after a partial write to get the error code.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

Add support for STATX_DIOALIGN to bcachefs, so that direct I/O alignment
restrictions are exposed to userspace in a generic way.

[Before]
```
./statx_test /mnt/bcachefs/test
statx(/mnt/bcachefs/test) = 0
dio mem align:0
dio offset align:0
```

[After]
```
./statx_test /mnt/bcachefs/test
statx(/mnt/bcachefs/test) = 0
dio mem align:1
dio offset align:512
```
Signed-off-by: Hongbo Li <lihongbo22@huawei.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

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

As part of improving btree key cache coherency, the bkey_cached.valid
flag is going away.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

Set the preferred folio order in the fgp_flags by calling
fgf_set_order(). Page cache will try to allocate large folio of the
preferred order whenever possible instead of allocating multiple 0 order
folios.

This improves the buffered write performance up to 1.25x with default
mount options and up to 1.57x when mounted with no_data_io option with
the following fio workload:

fio --name=bcachefs --filename=/mnt/test  --size=100G \
     --ioengine=io_uring --iodepth=16 --rw=write --bs=128k
Signed-off-by: Pankaj Raghav <p.raghav@samsung.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

Use FGP_WRITEBEGIN to avoid repeating the individual FGP flags before
starting a buffered write.
Signed-off-by: Pankaj Raghav <p.raghav@samsung.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

gc_lock is now only for synchronization between check_alloc_info and
interior btree updates - nothing else
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

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

Signed-off-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

this is an internal implementation detail - and we're improving key
cache coherency
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

new helper - small refactoring
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

we have a separate helper for releasing write locks
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>