171 Commits

Author SHA1 Message Date
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
Kent Overstreet
0990efaeea 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>
2023-10-22 17:09:36 -04:00
Kent Overstreet
e941ae7d3a 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>
2023-10-22 17:09:36 -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
a1783320d4 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>
2023-10-22 17:09:35 -04:00
Kent Overstreet
50b13beef0 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>
2023-10-22 17:09:34 -04:00
Kent Overstreet
30525f6863 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>
2023-10-22 17:09:33 -04:00
Kent Overstreet
b0babf2a34 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>
2023-10-22 17:09:32 -04:00
Kent Overstreet
d864842581 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>
2023-10-22 17:09:28 -04:00
Kent Overstreet
8570d775ca 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>
2023-10-22 17:09:27 -04:00
Kent Overstreet
2158fe463b 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>
2023-10-22 17:09:27 -04:00
Kent Overstreet
85d8cf161f 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>
2023-10-22 17:09:27 -04:00
Kent Overstreet
f7b6ca23b6 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>
2023-10-22 17:09:23 -04:00
Kent Overstreet
ce91abd60b 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>
2023-10-22 17:09:23 -04:00
Kent Overstreet
1f2d919250 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>
2023-10-22 17:09:22 -04:00
Kent Overstreet
a1e82d35f8 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>
2023-10-22 17:09:22 -04:00
Kent Overstreet
669f87a5da 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>
2023-10-22 17:09:21 -04:00
Kent Overstreet
f3e1f44433 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>
2023-10-22 17:09:19 -04:00
Kent Overstreet
084d42bbd6 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>
2023-10-22 17:09:17 -04:00
Kent Overstreet
32b26e8c7f 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>
2023-10-22 17:09:16 -04:00
Kent Overstreet
9a74f63c97 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>
2023-10-22 17:09:16 -04:00
Kent Overstreet
f527afea5a 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>
2023-10-22 17:09:15 -04:00
Kent Overstreet
d121172561 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>
2023-10-22 17:09:15 -04:00
Kent Overstreet
b0d1b70af8 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>
2023-10-22 17:09:14 -04:00
Kent Overstreet
e5fa91d7ac 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>
2023-10-22 17:09:14 -04:00
Kent Overstreet
9a796fdb06 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>
2023-10-22 17:09:14 -04:00
Kent Overstreet
d355c6f4f7 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>
2023-10-22 17:09:14 -04:00
Kent Overstreet
c075ff700f 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>
2023-10-22 17:09:12 -04:00
Kent Overstreet
db92f2ea5e 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>
2023-10-22 17:09:12 -04:00
Kent Overstreet
1d3ecd7ea7 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>
2023-10-22 17:09:11 -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
deb0e573b4 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>
2023-10-22 17:09:11 -04:00
Kent Overstreet
a0a568794d bcachefs: More renaming
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
2023-10-22 17:09:11 -04:00
Kent Overstreet
f7a966a3e2 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>
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
84841b0d13 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>
2023-10-22 17:09:10 -04:00
Kent Overstreet
0423fb7185 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>
2023-10-22 17:09:10 -04:00
Kent Overstreet
955af63441 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>
2023-10-22 17:09:09 -04:00
Kent Overstreet
e5af273fce 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>
2023-10-22 17:09:09 -04:00
Kent Overstreet
a88171c9e6 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>
2023-10-22 17:09:09 -04:00
Kent Overstreet
6e075b54a3 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>
2023-10-22 17:09:09 -04:00
Kent Overstreet
9f1833cadd 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>
2023-10-22 17:09:08 -04:00
Kent Overstreet
5aab663534 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>
2023-10-22 17:09:08 -04:00
Dan Robertson
d38494c462 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>
2023-10-22 17:09:08 -04:00
Kent Overstreet
8c3f6da9fc 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>
2023-10-22 17:09:06 -04:00
Kent Overstreet
953ee28a3e 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>
2023-10-22 17:09:06 -04:00
Kent Overstreet
5288e66a7b 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>
2023-10-22 17:09:05 -04:00
Kent Overstreet
509d3e0a8d 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>
2023-10-22 17:09:05 -04:00