36 Commits

Author SHA1 Message Date
Kent Overstreet
d4263e5638 bcachefs: Better use of locking helpers
Held btree locks are tracked in btree_path->nodes_locked and
btree_path->nodes_intent_locked. Upcoming patches are going to change
the representation in struct btree_path, so this patch switches to
proper helpers instead of direct access to these fields.

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
2023-10-22 17:09:39 -04:00
Kent Overstreet
8e5696698d bcachefs: Reorganize btree_locking.[ch]
Tidy things up a bit before doing more work in this file.

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
2023-10-22 17:09:39 -04:00
Kent Overstreet
cd5afabea1 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>
2023-10-22 17:09:39 -04:00
Kent Overstreet
4aba7d4569 bcachefs: Rename lock_held_stats -> btree_transaction_stats
Going to be adding more things to this in the next patch.

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2023-10-22 17:09:38 -04:00
Kent Overstreet
9f96568c0a 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>
2023-10-22 17:09:38 -04:00
Kent Overstreet
315c9ba6da bcachefs: BTREE_ITER_NO_NODE -> BCH_ERR codes
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
2023-10-22 17:09:37 -04:00
Kent Overstreet
fd211bc71c bcachefs: Don't set should_be_locked on paths that aren't locked
It doesn't make any sense to set should_be_locked on btree_paths that
aren't locked, and is often a bug - this patch adds assertions and fixes
some of those bugs.

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
2023-10-22 17:09:37 -04:00
Kent Overstreet
86b7445193 bcachefs: Fix bch2_btree_trans_to_text()
bch2_btree_trans_to_text() is used to print btree_transactions owned by
other threads; thus, it needs to be particularly careful. This fixes a
null ptr deref caused by racing with the owning thread changing
path->l[].b.

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
2023-10-22 17:09:37 -04:00
Kent Overstreet
549d173c1b 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>
2023-10-22 17:09:37 -04:00
Daniel Hill
c807ca95a6 bcachefs: added lock held time stats
We now record the length of time btree locks are held and expose this in debugfs.

Enabled via CONFIG_BCACHEFS_LOCK_TIME_STATS.

Signed-off-by: Daniel Hill <daniel@gluo.nz>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2023-10-22 17:09:35 -04:00
Daniel Hill
8bfe14e86a 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>
2023-10-22 17:09:35 -04:00
Kent Overstreet
c7ce27328b bcachefs: Also show when blocked on write locks
This consolidates some of the btree node lock path, so that when we're
blocked taking a write lock on a node it shows up in
bch2_btree_trans_to_text(), along with intent and read locks.

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
2023-10-22 17:09:23 -04:00
Kent Overstreet
3074bc0f7d Revert "bcachefs: Add more assertions for locking btree iterators out of order"
Figured out the bug we were chasing, and it had nothing to do with
locking btree iterators/paths out of order.

This reverts commit ff08733dd298c969aec7c7828095458f73fd5374.

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
2023-10-22 17:09:12 -04:00
Kent Overstreet
068bcaa589 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>
2023-10-22 17:09:11 -04:00
Kent Overstreet
67e0dd8f0d 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>
2023-10-22 17:09:11 -04:00
Kent Overstreet
78cf784eaa 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>
2023-10-22 17:09:11 -04:00
Kent Overstreet
9f6bd30703 bcachefs: Reduce iter->trans usage
Disfavoured, and should go away.

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
2023-10-22 17:09:10 -04:00
Kent Overstreet
5c1d808ad8 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>
2023-10-22 17:08:58 -04:00
Kent Overstreet
acb3b26e76 bcachefs: Move btree lock debugging to slowpath fn
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2023-10-22 17:08:58 -04:00
Kent Overstreet
a301dc38ef bcachefs: Improve tracing for transaction restarts
We have a bug where we can get stuck with a process spinning in
transaction restarts - need more information.

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2023-10-22 17:08:45 -04:00
Kent Overstreet
bd2bb273a0 bcachefs: Don't deadlock when btree node reuse changes lock ordering
Btree node lock ordering is based on the logical key. However, 'struct
btree' may be reused for a different btree node under memory pressure.
This patch uses the new six lock callback to check if a btree node is no
longer the node we wanted to lock before blocking.

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2023-10-22 17:08:41 -04:00
Kent Overstreet
515282ac7d bcachefs: Fix a deadlock
__bch2_btree_node_lock() was incorrectly using iter->pos as a proxy for
btree node lock ordering, this caused an off by one error that was
triggered by bch2_btree_node_get_sibling() getting the previous node.

This refactors the code to compare against btree node keys directly.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2023-10-22 17:08:41 -04:00
Kent Overstreet
495aabede3 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>
2023-10-22 17:08:40 -04:00
Kent Overstreet
bbe65614b7 bcachefs: Fix a deadlock
btree_node_lock_increment() was incorrectly skipping over the current
iter when checking if we should increment a node we already have locked.

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2023-10-22 17:08:39 -04:00
Kent Overstreet
b7ba66c845 bcachefs: Inline more of bch2_trans_commit hot path
The main optimization here is that if we let
bch2_replicas_delta_list_apply() fail, we can completely skip calling
bch2_bkey_replicas_marked_locked().

And assorted other small optimizations.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2023-10-22 17:08:30 -04:00
Kent Overstreet
fdfab313b6 bcachefs: Update path microoptimizations
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2023-10-22 17:08:27 -04:00
Kent Overstreet
60755344c6 bcachefs: kill BTREE_ITER_NOUNLOCK
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2023-10-22 17:08:22 -04:00
Kent Overstreet
b03b81dfd2 bcachefs: Don't pass around may_drop_locks
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2023-10-22 17:08:22 -04:00
Kent Overstreet
c43a6ef9a0 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>
2023-10-22 17:08:21 -04:00
Kent Overstreet
0f23836771 bcachefs: trans_for_each_iter()
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2023-10-22 17:08:18 -04:00
Kent Overstreet
5154704b29 bcachefs: Use deferred btree updates for inode updates
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2023-10-22 17:08:17 -04:00
Kent Overstreet
d0cc3defba bcachefs: More allocator startup improvements
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2023-10-22 17:08:14 -04:00
Kent Overstreet
ad7ae8d63f bcachefs: Btree locking fix, refactoring
Hit an assertion, probably spurious, indicating an iterator was unlocked
when it shouldn't have been (spurious because it wasn't locked at all
when the caller called btree_insert_at()).

Add a flag, BTREE_ITER_NOUNLOCK, and tighten up the assertions

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2023-10-22 17:08:12 -04:00
Kent Overstreet
e4ccb25131 bcachefs: make struct btree_iter a bit smaller
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2023-10-22 17:08:09 -04:00
Kent Overstreet
647d7b60b1 bcachefs: Fix an assertion in the btree node merge path
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2023-10-22 17:08:08 -04:00
Kent Overstreet
1c6fdbd8f2 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>
2023-10-22 17:08:07 -04:00