bcachefs: set_btree_iter_dontneed also clears should_be_locked

This is part of a larger series cleaning up the semantics of
should_be_locked and adding assertions around it; if we don't need an
iterator/path anymore, it clearly doesn't need to be locked.

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

bcachefs: Bump limit in btree_trans_too_many_iters()

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

bcachefs: Fix excess transaction restarts in __bchfs_fallocate()

drop_locks_do() should not be used in a fastpath without first trying
the do in nonblocking mode - the unlock and relock will cause excessive
transaction restarts and potentially livelocking with other threads that
are contending for the same locks.

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

bcachefs: growable btree_paths

XXX: we're allocating memory with btree locks held - bad

We need to plumb through an error path so we can do
allocate_dropping_locks() - but we're merging this now because it fixes
a transaction path overflow caused by indirect extent fragmentation, and
the resize path is rare.

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

bcachefs: trans->nr_paths

Start to plumb through dynamically growable btree_paths; this patch
replaces most BTREE_ITER_MAX references with trans->nr_paths.

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

bcachefs: rcu protect trans->paths

Upcoming patches are going to be changing trans->paths to a
reallocatable buffer. We need to guard against use after free when it's
used by other threads; this introduces RCU protection to those paths and
changes them to check for trans->paths == NULL

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

bcachefs: kill btree_path.idx

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

bcachefs: trans_for_each_path_with_node() no longer uses path->idx

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

bcachefs: trans_for_each_path() no longer uses path->idx

path->idx is now a code smell: we should be using path_idx_t, since it's
stable across btree path reallocation.

This is also a bit faster, using the same loop counter vs. fetching
path->idx from each path we iterate over.

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

bcachefs: kill trans_for_each_path_from()

dead code

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

bcachefs: bch2_btree_path_to_text() -> btree_path_idx_t

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

bcachefs: struct trans_for_each_path_inorder_iter

reducing our usage of path->idx

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

bcachefs: btree_iter -> btree_path_idx_t

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

bcachefs: bch2_btree_path_traverse() -> btree_path_idx_t

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

bcachefs: bch2_btree_path_make_mut() -> btree_path_idx_t

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

bcachefs: bch2_btree_path_set_pos() -> btree_path_idx_t

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

bcachefs; bch2_path_put() -> btree_path_idx_t

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

bcachefs: bch2_path_get() -> btree_path_idx_t

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

bcachefs: minor bch2_btree_path_set_pos() optimization

bpos_eq() is cheaper than bpos_cmp()

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

bcachefs: kill __bch2_btree_iter_peek_upto_and_restart()

dead code

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

bcachefs: for_each_btree_key() now declares loop iter

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

bcachefs: kill for_each_btree_key_norestart()

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

bcachefs: kill for_each_btree_key_old_upto()

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

bcachefs: for_each_btree_key_upto() -> for_each_btree_key_old_upto()

And for_each_btree_key2_upto -> for_each_btree_key_upto

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

bcachefs: bch2_trans_srcu_lock() should be static

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

bcachefs: kill btree_trans->wb_updates

the btree write buffer path now creates a journal entry directly

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

bcachefs: bch2_trans_node_add no longer uses trans_for_each_path()

In the future we'll be making trans->paths resizable and potentially
having _many_ more paths (for fsck); we need to start fixing algorithms
that walk each path in a transaction where possible.

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

bcachefs: reserve path idx 0 for sentinal

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

bcachefs: Rename for_each_btree_key2() -> for_each_btree_key()

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

bcachefs: Kill for_each_btree_key()

for_each_btree_key() handles transaction restarts, like
for_each_btree_key2(), but only calls bch2_trans_begin() after a
transaction restart - for_each_btree_key2() wraps every loop iteration
in a transaction.

The for_each_btree_key() behaviour is problematic when it leads to
holding the SRCU lock that prevents key cache reclaim for an unbounded
amount of time - there's no real need to keep it around.

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

bcachefs: continue now works in for_each_btree_key2()

continue now works as in any other loop

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

bcachefs: Refactor trans->paths_allocated to be standard bitmap

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

bcachefs: Improve trace_trans_restart_too_many_iters()

We now include the list of paths in use.

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

bcachefs: Kill btree_iter->journal_pos

For BTREE_ITER_WITH_JOURNAL, we memoize lookups in the journal keys, to
avoid the binary search overhead.

Previously we stashed the pos of the last key returned from the journal,
in order to force the lookup to be redone when rewinding.

Now bch2_journal_keys_peek_upto() handles rewinding itself when
necessary - so we can slim down btree_iter.

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

bcachefs: Kill memset() in bch2_btree_iter_init()

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

bcachefs: Kill BTREE_ITER_ALL_LEVELS

As discussed in the previous patch, BTREE_ITER_ALL_LEVELS appears to be
racy with concurrent interior node updates - and perhaps it is fixable,
but it's tricky and unnecessary.

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

bcachefs: fix invalid memory access in bch2_fs_alloc() error path

When bch2_fs_alloc() gets an error before calling
bch2_fs_btree_iter_init(), bch2_fs_btree_iter_exit() makes an invalid
memory access because btree_trans_list is uninitialized.

Signed-off-by: Thomas Bertschinger <tahbertschinger@gmail.com>
Fixes: 6bd68ec266ad ("bcachefs: Heap allocate btree_trans")
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

bcachefs: Add a comment for BTREE_INSERT_NOJOURNAL usage

BTREE_INSERT_NOJOURNAL is primarily used for a performance optimization
related to inode updates and fsync - document it.

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

bcachefs: rebalance_work btree is not a snapshots btree

rebalance_work entries may refer to entries in the extents btree, which
is a snapshots btree, or they may also refer to entries in the reflink
btree, which is not.

Hence rebalance_work keys may use the snapshot field but it's not
required to be nonzero - add a new btree flag to reflect this.

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

bcachefs: Ensure srcu lock is not held too long

The SRCU read lock that btree_trans takes exists to make it safe for
bch2_trans_relock() to deref pointers to btree nodes/key cache items we
don't have locked, but as a side effect it blocks reclaim from freeing
those items.

Thus, it's important to not hold it for too long: we need to
differentiate between bch2_trans_unlock() calls that will be only for a
short duration, and ones that will be for an unbounded duration.

This introduces bch2_trans_unlock_long(), to be used mainly by the data
move paths.

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

bcachefs: Fix btree_node_type enum

More forwards compatibility fixups: having BKEY_TYPE_btree at the end of
the enum conflicts with unnkown btree IDs, this shifts BKEY_TYPE_btree
to slot 0 and fixes things up accordingly.

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

bcachefs: Heap allocate btree_trans

We're using more stack than we'd like in a number of functions, and
btree_trans is the biggest object that we stack allocate.

But we have to do a heap allocatation to initialize it anyways, so
there's no real downside to heap allocating the entire thing.

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

bcachefs: Fix W=12 build errors

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

bcachefs: Fix bch2_propagate_key_to_snapshot_leaves()

When we handle a transaction restart in a nested context, we need to
return -BCH_ERR_transaction_restart_nested because we invalidated the
outer context's iterators and locks.

bch2_propagate_key_to_snapshot_leaves() wasn't doing this, this patch
fixes it to use trans_was_restarted().

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

bcachefs: Split up btree_update_leaf.c

We now have
btree_trans_commit.c
btree_update.c

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

bcachefs: Snapshot depth, skiplist fields

This extents KEY_TYPE_snapshot to include some new fields:
- depth, to indicate depth of this particular node from the root
- skip[3], skiplist entries for quickly walking back up to the root

These are to improve bch2_snapshot_is_ancestor(), making it O(ln(n))
instead of O(n) in the snapshot tree depth.

Skiplist nodes are picked at random from the set of ancestor nodes, not
some fixed fraction.

This introduces bcachefs_metadata_version 1.1, snapshot_skiplists.

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

bcachefs: Assorted sparse fixes

- endianness fixes
- mark some things static
- fix a few __percpu annotations
- fix silent enum conversions

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

bcachefs: Fix more lockdep splats in debug.c

Similar to previous fixes, we can't incur page faults while holding
btree locks.

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

bcachefs: allocate_dropping_locks()

Add two new helpers for allocating memory with btree locks held: The
idea is to first try the allocation with GFP_NOWAIT|__GFP_NOWARN, then
if that fails - unlock, retry with GFP_KERNEL, and then call
trans_relock().

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

bcachefs: drop_locks_do()

Add a new helper for the common pattern of:
- trans_unlock()
- do something
- trans_relock()

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

bcachefs: Convert -ENOENT to private error codes

As with previous conversions, replace -ENOENT uses with more informative
private error codes.

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

bcachefs: trans_for_each_path_safe()

bch2_btree_trans_to_text() is used on btree_trans objects that are owned
by different threads - when printing out deadlock cycles - so we need a
safe version of trans_for_each_path(), else we race with seeing a
btree_path that was just allocated and not fully initialized:

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

six locks: Seq now only incremented on unlock

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

six locks: Kill six_lock_state union

As suggested by Linus, this drops the six_lock_state union in favor of
raw bitmasks.

On the one hand, bitfields give more type-level structure to the code.
However, a significant amount of the code was working with
six_lock_state as a u64/atomic64_t, and the conversions from the
bitfields to the u64 were deemed a bit too out-there.

More significantly, because bitfield order is poorly defined (#ifdef
__LITTLE_ENDIAN_BITFIELD can be used, but is gross), incrementing the
sequence number would overflow into the rest of the bitfield if the
compiler didn't put the sequence number at the high end of the word.

The new code is a bit saner when we're on an architecture without real
atomic64_t support - all accesses to lock->state now go through
atomic64_*() operations.

On architectures with real atomic64_t support, we additionally use
atomic bit ops for setting/clearing individual bits.

Text size: 7467 bytes -> 4649 bytes - compilers still suck at
bitfields.

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

bcachefs: Move bch2_bkey_make_mut() to btree_update.h

It's for doing updates - this is where it belongs, and next pathes will
be changing these helpers to use items from btree_update.h.

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

bcachefs: bch2_bkey_get_iter() helpers

Introduce new helpers for a common pattern:

bch2_trans_iter_init();
bch2_btree_iter_peek_slot();

- bch2_bkey_get_iter_type() returns -ENOENT if it doesn't find a key of
the correct type
- bch2_bkey_get_val_typed() copies the val out of the btree to a
(typically stack allocated) variable; it handles the case where the
value in the btree is smaller than the current version of the type,
zeroing out the remainder.

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

bcachefs: Converting to typed bkeys is now allowed for err, null ptrs

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

bcachefs: bch2_btree_iter_peek_node_and_restart()

Minor refactoring for the Rust interface.

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

bcachefs: bch2_btree_iter_peek_and_restart_outlined()

Needed for interfacing with Rust - bindgen can't handle inline
functions, alas.

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

bcachefs: Split trans->last_begin_ip and trans->last_restarted_ip

These are two different things - this improves our debug assert
messages.

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

bcachefs: Fix erasure coding locking

This adds a new helper, bch2_trans_mutex_lock(), for locking a mutex -
dropping and retaking btree locks as needed.

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

bcachefs: Use for_each_btree_key_upto() more consistently

It's important that in BTREE_ITER_FILTER_SNAPSHOTS mode we always use
peek_upto() and provide an end for the interval we're searching for -
otherwise, when we hit the end of the inode the next inode be in a
different subvolume and not have any keys in the current snapshot, and
we'd iterate over arbitrarily many keys before returning one.

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

bcachefs: bch2_trans_in_restart_error()

This replaces various BUG_ON() assertions with panics that tell us where
the restart was done and the restart type.

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

bcachefs: Inline bch2_btree_path_traverse() fastpath

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

bcachefs: bch2_trans_relock_notrace()

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

bcachefs: btree_iter->ip_allocated

In debug mode, we now track where btree iterators and paths are
initialized/allocated - helpful in tracking down btree path overflows.

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

bcachefs: New btree helpers

This introduces some new conveniences, to help cut down on boilerplate:

- bch2_trans_kmalloc_nomemzero() - performance optimiation
- bch2_bkey_make_mut()
- bch2_bkey_get_mut()
- bch2_bkey_get_mut_typed()
- bch2_bkey_alloc()

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

bcachefs: New bpos_cmp(), bkey_cmp() replacements

This patch introduces
- bpos_eq()
- bpos_lt()
- bpos_le()
- bpos_gt()
- bpos_ge()

and equivalent replacements for bkey_cmp().

Looking at the generated assembly these could probably be improved
further, but we already see a significant code size improvement with
this patch.

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

bcachefs: Optimize bch2_trans_iter_init()

When flags & btree_id are constants, we can constant fold the entire
calculation of the actual iterator flags - and the whole thing becomes
small enough to inline.

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

bcachefs: Fix for_each_btree_key2()

Previously, when we exited from the loop body with a break statement
_ret wouldn't have been assigned to yet, and we could spuriously return
a transaction restart error.

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

bcachefs: Fix return code from btree_path_traverse_one()

trans->restarted is a positive error code, not the usual negative

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

bcachefs: Fixes for building in userspace

- Marking a non-static function as inline doesn't actually work and is
now causing problems - drop that

- Introduce BCACHEFS_LOG_PREFIX for when we want to prefix log messages
with bcachefs (filesystem name)

- Userspace doesn't have real percpu variables (maybe we can get this
fixed someday), put an #ifdef around bch2_disk_reservation_add()
fastpath

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

bcachefs: Optimize bch2_trans_init()

Now we store the transaction's fn idx in a local variable, instead of
redoing the lookup every time we call bch2_trans_init().

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

bcachefs: bch2_trans_locked()

Useful debugging function.

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

bcachefs: Inline bch2_trans_kmalloc() fast path

Small performance optimization.

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

bcachefs: Deadlock cycle detector

We've outgrown our own deadlock avoidance strategy.

The btree iterator API provides an interface where the user doesn't need
to concern themselves with lock ordering - different btree iterators can
be traversed in any order. Without special care, this will lead to
deadlocks.

Our previous strategy was to define a lock ordering internally, and
whenever we attempt to take a lock and trylock() fails, we'd check if
the current btree transaction is holding any locks that cause a lock
ordering violation. If so, we'd issue a transaction restart, and then
bch2_trans_begin() would re-traverse all previously used iterators, but
in the correct order.

That approach had some issues, though.
- Sometimes we'd issue transaction restarts unnecessarily, when no
deadlock would have actually occured. Lock ordering restarts have
become our primary cause of transaction restarts, on some workloads
totally 20% of actual transaction commits.

- To avoid deadlock or livelock, we'd often have to take intent locks
when we only wanted a read lock: with the lock ordering approach, it
is actually illegal to hold _any_ read lock while blocking on an intent
lock, and this has been causing us unnecessary lock contention.

- It was getting fragile - the various lock ordering rules are not
trivial, and we'd been seeing occasional livelock issues related to
this machinery.

So, since bcachefs is already a relational database masquerading as a
filesystem, we're stealing the next traditional database technique and
switching to a cycle detector for avoiding deadlocks.

When we block taking a btree lock, after adding ourself to the waitlist
but before sleeping, we do a DFS of btree transactions waiting on other
btree transactions, starting with the current transaction and walking
our held locks, and transactions blocking on our held locks.

If we find a cycle, we emit a transaction restart. Occasionally (e.g.
the btree split path) we can not allow the lock() operation to fail, so
if necessary we'll tell another transaction that it has to fail.

Result: trans_restart_would_deadlock events are reduced by a factor of
10 to 100, and we'll be able to delete a whole bunch of grotty, fragile
code.

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

bcachefs: All held locks must be in a btree path

With the new deadlock cycle detector, it's critical that all held locks
be marked in a btree_path, because that's what the cycle detector
traverses - any locks that aren't correctly marked will cause deadlocks.

This changes the btree_path to allocate some btree_paths for the new
nodes, since until the final update is done we otherwise don't have a
path referencing them.

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

bcachefs: Add persistent counters for all tracepoints

Also, do some reorganizing/renaming, convert atomic counters in bch_fs
to persistent counters, and add a few missing counters.

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

bcachefs: Make more btree_paths available

- Don't decrease BTREE_ITER_MAX when building with CONFIG_LOCKDEP
anymore. The lockdep table sizes are configurable now, we don't need
this anymore.
- btree_trans_too_many_iters() is less conservative now. Previously it
was causing a transaction restart if we had used more than
BTREE_ITER_MAX / 2 paths, change this to BTREE_ITER_MAX - 8.

This helps with excessive transaction restarts/livelocks in the bucket
allocator path.

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

bcachefs: Track maximum transaction memory

This patch
- tracks maximum bch2_trans_kmalloc() memory used in btree_transaction_stats
- makes it available in debugfs
- switches bch2_trans_init() to using that for the amount of memory to
preallocate, instead of the parameter passed in

This drastically reduces transaction restarts, and means we no longer
need to track this in the source code.

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

bcachefs: btree_locking.c

Start to centralize some of the locking code in a new file; more locking
code will be moving here in the future.

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

bcachefs: Add assertions for unexpected transaction restarts

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

bcachefs: Increment restart count in bch2_trans_begin()

Instead of counting transaction restarts, count when the transaction is
restarted: if bch2_trans_begin() was called when the transaction wasn't
restarted we need to ensure restart_count is still incremented.

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

bcachefs: Track the maximum btree_paths ever allocated by each transaction

We need a way to check if the machinery for handling btree_paths with in
a transaction is behaving reasonably, as it often has not been - we've
had bugs with transaction path overflows caused by duplicate paths and
plenty of other things.

This patch tracks, per transaction fn, the most btree paths ever
allocated by that transaction and makes it available in debugfs.

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

bcachefs: Tracepoint improvements

Our types are exported to the tracepoint code, so it's not necessary to
break things out individually when passing them to tracepoints - we can
also call other functions from TP_fast_assign().

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

bcachefs: Fix incorrectly freeing btree_path in alloc path

Clearing path->preserve means the path will be dropping in
bch2_trans_begin() - but on transaction restart, we're likely to need
that path again.

This fixes a livelock in the allocation path.

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

bcachefs: for_each_btree_key_reverse()

This adds a new macro, like for_each_btree_key2(), but for iterating in
reverse order.

Also, change for_each_btree_key2() to properly check the return value of
bch2_btree_iter_advance().

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

bcachefs: EINTR -> BCH_ERR_transaction_restart

Now that we have error codes, with subtypes, we can switch to our own
error code for transaction restarts - and even better, a distinct error
code for each transaction restart reason: clearer code and better
debugging.

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

bcachefs: btree_trans_too_many_iters() is now a transaction restart

All transaction restarts need a tracepoint - this is essential for
debugging

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

bcachefs: Add a counter for btree_trans restarts

This will help us improve nested transactions - we need to add
assertions that whenever an inner transaction handles a restart, it
still returns -EINTR to the outer transaction.

This also adds nested_lockrestart_do() and nested_commit_do() which use
the new counters to correctly return -EINTR when the transaction was
restarted.

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

bcachefs: lock time stats prep work.

We need the caller name and a place to store our results, btree_trans provides this.

Signed-off-by: Daniel Hill <daniel@gluo.nz>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

bcachefs: for_each_btree_key2()

This introduces two new macros for iterating through the btree, with
transaction restart handling
- for_each_btree_key2()
- for_each_btree_key_commit()

Every iteration is now in an implicit transaction, and - as with
lockrestart_do() and commit_do() - returning -EINTR will cause the
transaction to be restarted, at the same key.

This patch converts a bunch of code that was open coding this to these
new macros, saving a substantial amount of code.

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

bcachefs: Improve an error message

When inserting a key type that's not valid for a given btree, we should
print out which btree we were inserting into.

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

bcachefs: Fix journal_keys_search() overhead

Previously, on every btree_iter_peek() operation we were searching the
journal keys, doing a full binary search - which was slow.

This patch fixes that by saving our position in the journal keys, so
that we only do a full binary search when moving our position backwards
or a large jump forwards.

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

bcachefs: bch2_btree_iter_peek_all_levels()

This adds bch2_btree_iter_peek_all_levels(), which returns keys from
every level of the btree - interior nodes included - in monotonically
increasing order, soon to be used by the backpointers check & repair
code.

- BTREE_ITER_ALL_LEVELS can now be passed to for_each_btree_key() to
iterate thusly, much like BTREE_ITER_SLOTS

- The existing algorithm in bch2_btree_iter_advance() doesn't work with
peek_all_levels(): we have to defer the actual advancing until the
next time we call peek, where we have the btree path traversed and
uptodate. So, we add an advanced bit to btree_iter; when
BTREE_ITER_ALL_LEVELS is set bch2_btree_iter_advanced() just marks
the iterator as advanced.

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

bcachefs: btree_path_make_mut() clears should_be_locked

This fixes a bug where __bch2_btree_node_update_key() wasn't clearing
should_be_locked, leading to bch2_btree_path_traverse() always failing -
all callers of btree_path_make_mut() want should_be_locked cleared, so
do it there.

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

bcachefs: bch2_trans_updates_to_text()

This turns bch2_dump_trans_updates() into a to_text() method - this way
it can be used by debug tracing.

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

bcachefs: bch2_trans_inconsistent()

Add a new error macro that also dumps transaction updates in addition to
doing an emergency shutdown - when a transaction update discovers or is
causing a fs inconsistency, it's helpful to see what updates it was
doing.

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

bcachefs: bch2_btree_iter_peek_upto()

In BTREE_ITER_FILTER_SNAPHOTS mode, we skip over keys in unrelated
snapshots. When we hit the end of an inode, if the next inode(s) are in
a different subvolume, we could potentially have to skip past many keys
before finding a key we can return to the caller, so they can terminate
the iteration.

This adds a peek_upto() variant to solve this problem, to be used when
we know the range we're searching within.

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

bcachefs: BTREE_ITER_WITH_KEY_CACHE

This is the start of cache coherency with the btree key cache - this
adds a btree iterator flag that causes lookups to also check the key
cache when we're iterating over the btree (not iterating over the key
cache).

Note that we could still race with another thread creating at item in
the key cache and updating it, since we aren't holding the key cache
locked if it wasn't found. The next patch for the update path will
address this by causing the transaction to restart if the key cache is
found to be dirty.

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

bcachefs: bch2_btree_path_set_pos()

bch2_btree_path_set_pos() is now available outside of btree_iter.c

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

bcachefs: iter->update_path

With BTREE_ITER_FILTER_SNAPSHOTS, we have to distinguish between the
path where the key was found, and the path for inserting into the
current snapshot. This adds a new field to struct btree_iter for saving
a path for the current snapshot, and plumbs it through
bch2_trans_update().

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

bcachefs: Refactor bch2_btree_iter()

This splits bch2_btree_iter() up into two functions: an inner function
that handles BTREE_ITER_WITH_JOURNAL, BTREE_ITER_WITH_UPDATES, and
iterating acrcoss leaf nodes, and an outer one that implements
BTREE_ITER_FILTER_SNAPHSOTS.

This is prep work for remember a btree_path at our update position in
BTREE_ITER_FILTER_SNAPSHOTS mode.

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

bcachefs: Switch to __func__for recording where btree_trans was initialized

Symbol decoding, via %ps, isn't supported in userspace - this will also
be faster when we're using trans->fn in the fast path, as with the new
BCH_JSET_ENTRY_log journal messages.

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

bcachefs: BTREE_ITER_NOPRESERVE

This adds a flag to not mark the initial btree_path as preserve, for
paths that we expect to be cheap to reconstitute if necessary - this
solves a btree_path overflow caused by need_whiteout_for_snapshot().

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

bcachefs: Apply workaround for too many btree iters to read path

Reading from cached data, which calls bch2_bucket_io_time_reset(), is
leading to transaction iterator overflows - this standardizes the
workaround.

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

bcachefs: bch2_assert_pos_locked()

This adds a new assertion to be used by bch2_inode_update_after_write(),
which updates the VFS inode based on the update to the btree inode we
just did - we require that the btree inode still be locked when we do
that update.

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

bcachefs: path->should_be_locked fixes

- We should only be clearing should_be_locked in btree_path_set_pos() -
it's the responsiblity of the btree_path code, not the btree_iter
code.

- bch2_path_put() needs to pay attention to path->should_be_locked, to
ensure we don't drop locks we're supposed to be keeping.

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

bcachefs: Fix upgrade_readers()

The bch2_btree_path_upgrade() call was failing and tripping an assert -
path->level + 1 is in this case not necessarily exactly what we want,
fix it by upgrading exactly the locks we want.

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

bcachefs: More general fix for transaction paths overflow

for_each_btree_key() now calls bch2_trans_begin() as needed; that means,
we can also call it when we're in danger of overflowing transaction
paths.

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

bcachefs: Must check for errors from bch2_trans_cond_resched()

But we don't need to call it from outside the btree iterator code
anymore, since it's called by bch2_trans_begin() and
bch2_btree_path_traverse().

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

bcachefs: Fix restart handling in for_each_btree_key()

Code that uses for_each_btree_key often wants transaction restarts to be
handled locally and not returned. Originally, we wouldn't return
transaction restarts if there was a single iterator in the transaction -
the reasoning being if there weren't other iterators being invalidated,
and the current iterator was being advanced/retraversed, there weren't
any locks or iterators we were required to preserve.

But with the btree_path conversion that approach doesn't work anymore -
even when we're using for_each_btree_key() with a single iterator there
will still be two paths in the transaction, since we now always preserve
the path at the pos the iterator was initialized at - the reason being
that on restart we often restart from the same place.

And it turns out there's now a lot of for_each_btree_key() uses that _do
not_ want transaction restarts handled locally, and should be returning
them.

This patch splits out for_each_btree_key_norestart() and
for_each_btree_key_continue_norestart(), and converts existing users as
appropriate. for_each_btree_key(), for_each_btree_key_continue(), and
for_each_btree_node() now handle transaction restarts themselves by
calling bch2_trans_begin() when necessary - and the old hack to not
return transaction restarts when there's a single path in the
transaction has been deleted.

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

bcachefs: bch2_trans_exit() no longer returns errors

Now that peek_node()/next_node() are converted to return errors
directly, we don't need bch2_trans_exit() to return errors - it's
cleaner this way and wasn't used much anymore.

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

bcachefs: for_each_btree_node() now returns errors directly

This changes for_each_btree_node() to work like for_each_btree_key(),
and to that end bch2_btree_iter_peek_node() and next_node() also return
error ptrs.

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

bcachefs: BTREE_ITER_FILTER_SNAPSHOTS

For snapshots, we need to implement btree lookups that return the first
key that's an ancestor of the snapshot ID the lookup is being done in -
and filter out keys in unrelated snapshots. This patch adds the btree
iterator flag BTREE_ITER_FILTER_SNAPSHOTS which does that filtering.

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

bcachefs: Optimize btree lookups in write path

This patch significantly reduces the number of btree lookups required in
the extent update path.

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

bcachefs: Tighten up btree locking invariants

New rule is: if a btree path holds any locks it should be holding
precisely the locks wanted (accoringing to path->level and
path->locks_want).

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

bcachefs: Add more assertions for locking btree iterators out of order

btree_path_traverse_all() traverses btree iterators in sorted order, and
thus shouldn't see transaction restarts due to potential deadlocks - but
sometimes we do. This patch adds some more assertions and tracks some
more state to help track this down.

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

bcachefs: btree_path

This splits btree_iter into two components: btree_iter is now the
externally visible componont, and it points to a btree_path which is now
reference counted.

This means we no longer have to clone iterators up front if they might
be mutated - btree_path can be shared by multiple iterators, and cloned
if an iterator would mutate a shared btree_path. This will help us use
iterators more efficiently, as well as slimming down the main long lived
state in btree_trans, and significantly cleans up the logic for iterator
lifetimes.

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

bcachefs: Kill BTREE_ITER_NEED_PEEK

This was used for an optimization that hasn't existing in quite awhile
- iter->uptodate will probably be going away as well.

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

bcachefs: More renaming

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

bcachefs: Clean up/rename bch2_trans_node_* fns

These utility functions are for managing btree node state within a
btree_trans - rename them for consistency, and drop some unneeded
arguments.

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

bcachefs: Further reduce iter->trans usage

This is prep work for splitting btree_path out from btree_iter -
btree_path will not have a pointer to btree_trans.

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

bcachefs: Reduce iter->trans usage

Disfavoured, and should go away.

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

bcachefs: bch2_dump_trans_iters_updates()

This factors out bch2_dump_trans_iters_updates() from the iter alloc
overflow path, and makes some small improvements to what it prints.

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

bcachefs: Keep a sorted list of btree iterators

This will be used to make other operations on btree iterators within a
transaction more efficient, and enable some other improvements to how we
manage btree iterators.

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

bcachefs: __bch2_trans_commit() no longer calls bch2_trans_reset()

It's now the caller's responsibility to call bch2_trans_begin.

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

bcachefs: trans->restarted

Start tracking when btree transactions have been restarted - and assert
that we're always calling bch2_trans_begin() immediately after
transaction restart.

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

bcachefs: Clean up interior update paths

Btree node merging now happens prior to transaction commit, not after,
so we don't need to pay attention to BTREE_INSERT_NOUNLOCK.

Also, foreground_maybe_merge shouldn't be calling
bch2_btree_iter_traverse_all() - this is becoming private to the btree
iterator code and should only be called by bch2_trans_begin().

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

bcachefs: bch2_btree_iter_relock_intent()

This adds a new helper for btree_cache.c that does what we want where
the iterator is still being traverse - and also eliminates some
unnecessary transaction restarts.

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

bcachefs: Update btree ptrs after every write

This closes a significant hole (and last known hole) in our ability to
verify metadata. Previously, since btree nodes are log structured, we
couldn't detect lost btree writes that weren't the first write to a
given node. Additionally, this seems to have lead to some significant
metadata corruption on multi device filesystems with metadata
replication: since a write may have made it to one device and not
another, if we read that btree node back from the replica that did have
that write and started appending after that point, the other replica
would have a gap in the bset entries and reading from that replica
wouldn't find the rest of the bsets.

But, since updates to interior btree nodes are now journalled, we can
close this hole by updating pointers to btree nodes after every write
with the currently written number of sectors, without negatively
affecting performance. This means we will always detect lost or corrupt
metadata - it also means that our btree is now a curious hybrid of COW
and non COW btrees, with all the benefits of both (excluding
complexity).

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

bcachefs: Tighten up btree_iter locking assertions

We weren't correctly verifying that we had interior node intent locks -
this patch also fixes bugs uncovered by the new assertions.

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

bcachefs: docs: add docs for bch2_trans_reset

Add basic kernel docs for bch2_trans_reset and bch2_trans_begin.

Signed-off-by: Dan Robertson <dan@dlrobertson.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

bcachefs: Improve iter->should_be_locked

Adding iter->should_be_locked introduced a regression where it ended up
not being set on the iterator passed to bch2_btree_update_start(), which
is definitely not what we want.

This patch requires it to be set when calling bch2_trans_update(), and
adds various fixups to make that happen.

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

bcachefs: Kill bch2_btree_iter_peek_cached()

It's now been rolled into bch2_btree_iter_peek_slot()

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

bcachefs: BTREE_ITER_WITH_UPDATES

This drops bch2_btree_iter_peek_with_updates() and replaces it with a
new flag, BTREE_ITER_WITH_UPDATES, and also reworks
bch2_btree_iter_peek_slot() to respect it too.

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

bcachefs: Child btree iterators

This adds the ability for btree iterators to own child iterators - to be
used by an upcoming rework of bch2_btree_iter_peek_slot(), so we can
scan forwards while maintaining our current position.

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

bcachefs: btree_iter->should_be_locked

Add a field to struct btree_iter for tracking whether it should be
locked - this fixes spurious transaction restarts in
bch2_trans_relock().

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

bcachefs: Improve btree iterator tracepoints

This patch adds some new tracepoints to the btree iterator code, and
adds new fields to the existing tracepoints - primarily for the iterator
position.

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

bcachefs: Improve bch2_btree_iter_traverse_all()

By changing it to upgrade iterators to intent locks to avoid lock
restarts we can simplify __bch2_btree_node_lock() quite a bit - this
fixes a probable bug where it could potentially drop a lock on an
unrelated error but still succeed instead of causing a transaction
restart.

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

bcachefs: Drop some memset() calls

gcc is emitting rep stos here, which is silly (and slow) for an 8 byte
memset.

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

bcachefs: Increase commality between BTREE_ITER_NODES and BTREE_ITER_KEYS

Eventually BTREE_ITER_NODES should be going away. This patch is to fix a
transaction iterator overflow in the btree node merge path because
BTREE_ITER_NODES iterators couldn't be reused.

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

bcachefs: Drop trans->nounlock

Since we're no longer doing btree node merging post commit, we can now
delete a bunch of code.

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

bcachefs: Start using bpos.snapshot field

This patch starts treating the bpos.snapshot field like part of the key
in the btree code:

* bpos_successor() and bpos_predecessor() now include the snapshot field
* Keys in btrees that will be using snapshots (extents, inodes, dirents
and xattrs) now always have their snapshot field set to U32_MAX

The btree iterator code gets a new flag, BTREE_ITER_ALL_SNAPSHOTS, that
determines whether we're iterating over keys in all snapshots or not -
internally, this controlls whether bkey_(successor|predecessor)
increment/decrement the snapshot field, or only the higher bits of the
key.

We add a new member to struct btree_iter, iter->snapshot: when
BTREE_ITER_ALL_SNAPSHOTS is not set, iter->pos.snapshot should always
equal iter->snapshot, which will be 0 for btrees that don't use
snapshots, and alsways U32_MAX for btrees that will use snapshots
(until we enable snapshot creation).

This patch also introduces a new metadata version number, and compat
code for reading from/writing to older versions - this isn't a forced
upgrade (yet).

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

bcachefs: Fix for bch2_trans_commit() unlocking when it's not supposed to

When we pass BTREE_INSERT_NOUNLOCK bch2_trans_commit isn't supposed to
unlock after a successful commit, but it was calling
bch2_trans_cond_resched() - oops.

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

bcachefs: Split btree_iter_traverse and bch2_btree_iter_traverse()

External (to the btree iterator code) users of bch2_btree_iter_traverse
expect that on success the iterator will be pointed at iter->pos and
have that position locked - but since we split iter->pos and
iter->real_pos, that means it has to update iter->real_pos if necessary.

Internal users don't expect it to modify iter->real_pos, so we need two
separate functions.

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

bcachefs: Update iter->real_pos lazily

peek() has to update iter->real_pos - there's no need for
bch2_btree_iter_set_pos() to update it as well.

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

bcachefs: Replace bch2_btree_iter_next() calls with bch2_btree_iter_advance

The way btree iterators work internally has been changing, particularly
with the iter->real_pos changes, and bch2_btree_iter_next() is no longer
hyper optimized - it's just advance followed by peek, so it's more
efficient to just call advance where we're not using the return value of
bch2_btree_iter_next().

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

bcachefs: btree_iter_set_dontneed()

This is a bit clearer than using bch2_btree_iter_free().

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

bcachefs: Fsck code refactoring

Change fsck code to always put btree iterators - also, make some flow
control improvements to deal with lock restarts better, and refactor
check_extents() to not walk extents twice for counting/checking
i_sectors.

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

bcachefs: __bch2_trans_get_iter() refactoring, BTREE_ITER_NOT_EXTENTS

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

bcachefs: Simplify for_each_btree_key()

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

bcachefs: btree_iter_prev_slot()

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

bcachefs: btree_iter_live()

New helper to clean things up a bit - also, improve iter->flags
handling.

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

bcachefs: Kill bch2_btree_iter_set_pos_same_leaf()

The only reason we were keeping this around was for
BTREE_INSERT_NOUNLOCK semantics - if bch2_btree_iter_set_pos() advances
to the next leaf node, it'll drop the lock on the node that we just
inserted to.

But we don't rely on BTREE_INSERT_NOUNLOCK semantics for the extents
btree, just the inodes btree, and if we do need it for the extents btree
in the future we can do it more cleanly by cloning the iterator - this
lets us delete some special cases in the btree iterator code, which is
complicated enough as it is.

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

bcachefs: Fix __btree_iter_next() when all iters are in use_next() when all iters are in use

Also, print out more information on btree transaction iterator overflow.

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

bcachefs: bch2_trans_get_iter() no longer returns errors

Since we now always preallocate the maximum number of iterators when we
initialize a btree transaction, getting an iterator never fails - we can
delete a fair amount of error path code.

This patch also simplifies the iterator allocation code a bit.

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

bcachefs: Fix spurious transaction restarts

The checks for lock ordering violations weren't quite right.

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

bcachefs: Fix btree updates when mixing cached and non cached iterators

There was a bug where bch2_trans_update() would incorrectly delete a
pending update where the new update did not actually overwrite the
existing update, because we were incorrectly using BTREE_ITER_TYPE when
sorting pending btree updates.

This affects the pending patch to use cached iterators for inode
updates.

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

bcachefs: Btree key cache

This introduces a new kind of btree iterator, cached iterators, which
point to keys cached in a hash table. The cache also acts as a write
cache - in the update path, we journal the update but defer updating the
btree until the cached entry is flushed by journal reclaim.

Cache coherency is for now up to the users to handle, which isn't ideal
but should be good enough for now.

These new iterators will be used for updating inodes and alloc info (the
alloc and stripes btrees).

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

bcachefs: bch2_trans_downgrade()

bch2_btree_iter_downgrade() was looping over all iterators in a
transaction; bch2_trans_downgrade() should be doing that.

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

bcachefs: Fix a deadlock in bch2_btree_node_get_sibling()

There was a bad interaction with bch2_btree_iter_set_pos_same_leaf(),
which can leave a btree node locked that is just outside iter->pos,
breaking the lock ordering checks in __bch2_btree_node_lock(). Ideally
we should get rid of this corner case, but for now fix it locally with
verbose comments.

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

bcachefs: Add debug code to print btree transactions

Intented to help debug deadlocks, since we can't use lockdep to check
btree node lock ordering.

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

bcachefs: Trace where btree iterators are allocated

This will help with iterator overflow bugs.

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

bcachefs: Kill bkey_type_successor

Previously, BTREE_ID_INODES was special - inodes were indexed by the
inode field, which meant the offset field of struct bpos wasn't used,
which led to special cases in e.g. the btree iterator code.

Now, inodes in the inodes btree are indexed by the offset field.

Also: prevously min_key was special for extents btrees, min_key for
extents would equal max_key for the previous node. Now, min_key =
bkey_successor() of the previous node, same as non extent btrees.

This means we can completely get rid of
btree_type_sucessor/predecessor.

Also make some improvements to the metadata IO validate/compat code.

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

bcachefs: btree_iter_peek_with_updates()

Introduce a new iterator method that provides a consistent view of the
btree plus uncommitted updates.

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

bcachefs: Iterator debug code improvements

More aggressively checking iterator invariants, and fixing the resulting
bugs. Also greatly simplifying iter_next() and iter_next_slot() - they
were hyper optimized before, but the optimizations were getting too
brittle.

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

bcachefs: Kill TRANS_RESET_MEM|TRANS_RESET_ITERS

All iterators should be released now with bch2_trans_iter_put(), so
TRANS_RESET_ITERS shouldn't be needed anymore, and TRANS_RESET_MEM is
always used.

Also convert more code to __bch2_trans_do().

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

bcachefs: __bch2_btree_iter_set_pos()

This one takes an additional argument for whether we're searching for >=
or > the search key.

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

bcachefs: Use bch2_trans_reset in bch2_trans_commit()

Clean up a bit of duplicated code.

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

bcachefs: bch2_trans_reset() calls should be at the tops of loops

It needs to be called when we get -EINTR due to e.g. lock restart - this
fixes a transaction iterators overflow bug.

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

bcachefs: bch2_btree_iter_fix_key_modified()

This is considerably cheaper than bch2_btree_node_iter_fix(), for cases
where the key was only modified and key ordering isn't changing.

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

bcachefs: Refactor bch2_trans_commit() path

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

bcachefs: Rework btree iterator lifetimes

The btree_trans struct needs to memoize/cache btree iterators, so that
on transaction restart we don't have to completely redo btree lookups,
and so that we can do them all at once in the correct order when the
transaction had to restart to avoid a deadlock.

This switches the btree iterator lookups to work based on iterator
position, instead of trying to match them up based on the stack trace.

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

bcachefs: Improve error handling for for_each_btree_key_continue()

Change it to match for_each_btree_key()

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

bcachefs: bch2_btree_iter_peek_prev()

Last of the basic operations for iterating forwards and backwards over
the btree: we now have
- peek(), returns key >= iter->pos
- next(), returns key > iter->pos
- peek_prev(), returns key <= iter->pos
- prev(), returns key < iter->pos

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

bcachefs: Optimize calls to bch2_btree_iter_traverse()

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

bcachefs: Do updates in order they were queued up in

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

bcachefs: fix for_each_btree_key()

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

bcachefs: Rip out old hacky transaction restart tracing

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

bcachefs: More work to avoid transaction restarts

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

bcachefs: Avoid spurious transaction restarts

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

bcachefs: Ensure bch2_btree_iter_next() always advances

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

bcachefs: Delete duplicate code

Also rename for consistency

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

bcachefs: improved btree locking tracepoints

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

bcachefs: kill BTREE_ITER_NOUNLOCK

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

bcachefs: Don't pass around may_drop_locks

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

bcachefs: Kill remaining bch2_btree_iter_unlock() uses

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

bcachefs: btree_bkey_cached_common

This is prep work for the btree key cache: btree iterators will point to
either struct btree, or a new struct bkey_cached.

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

bcachefs: Don't hardcode BTREE_ID_EXTENTS

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

bcachefs: Return errors from for_each_btree_key()

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

bcachefs: traverse all iterators on transaction restart

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

bcachefs: Add iter->idx

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

bcachefs: Kill btree_iter->next

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

bcachefs: trans_for_each_iter()

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

bcachefs: Better bch2_trans_copy_iter()

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

bcachefs: Btree iterators now always have a btree_trans

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

bcachefs: Only get btree iters from btree transactions

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

bcachefs: Btree iter improvements

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

bcachefs: Remove direct use of bch2_btree_iter_link()

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

bcachefs: Use deferred btree updates for inode updates

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

bcachefs: More allocator startup improvements

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

bcachefs: Pass around bset_tree less

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

bcachefs: convert bchfs_write_index_update() to bch2_extent_update()

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

bcachefs: mempoolify btree_trans

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

bcachefs: make struct btree_iter a bit smaller

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

bcachefs: trace transaction restarts

exceptionally crappy "tracing", but it's a start at documenting the
places restarts can be triggered

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

bcachefs: Initial commit

Initially forked from drivers/md/bcache, bcachefs is a new copy-on-write
filesystem with every feature you could possibly want.

Website: https://bcachefs.org

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