This adds a new method of doing btree updates - a straight write buffer,
implemented as a flat fixed size array.
This is only useful when we don't need to read from the btree in order
to do the update, and when reading is infrequent - perfect for the LRU
btree.
This will make LRU btree updates fast enough that we'll be able to use
it for persistently indexing buckets by fragmentation, which will be a
massive boost to copygc performance.
Changes:
- A new btree_insert_type enum, for btree_insert_entries. Specifies
btree, btree key cache, or btree write buffer.
- bch2_trans_update_buffered(): updates via the btree write buffer
don't need a btree path, so we need a new update path.
- Transaction commit path changes:
The update to the btree write buffer both mutates global, and can
fail if there isn't currently room. Therefore we do all write buffer
updates in the transaction all at once, and also if it fails we have
to revert filesystem usage counter changes.
If there isn't room we flush the write buffer in the transaction
commit error path and retry.
- A new persistent option, for specifying the number of entries in the
write buffer.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
When we unlock in order to submit IO, the next relock event is likely to
fail if submit_bio() blocked - we shouldn't those events in our _fail
stats, since those are expected events and shouldn't cause test
failures.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
We need to call bch2_trans_update_max_paths() before marking the new
path as allocated, since we're not initializing it yet.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
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>
This uses the new _ip() interface to six locks and hooks it up to
btree_path->ip_allocated, when available.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
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>
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>
This is something we need to do more widely: instead of bothering with
GFP_NOIO/GFP_NOFS, if we need to allocate memory while holding locks:
- first attempt the allocation with GFP_NOWAIT
- if that fails, drop btree locks with bch2_trans_unlock(), then
retry with GFP_KERNEL.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
We need to take a ref on a path while we're traversing it: this fixes a
bug with paths getting reused while being traversed, in the key cache
fill code.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
While a btree transaction is running, we hold a SRCU read lock on the
btree key cache that prevents btree key cache keys from being freed -
this is so that relock() operations won't access freed memory.
The downside of this is that long running btree transactions prevent
memory from being freed from the key cache. This adds a check in
bch2_trans_begin() - if the transaction has been running longer than 1
second, drop and retake the SRCU read lock and zero out pointers to
unlock key cache paths.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
When we started stashing the key being overwritten in
btree_insert_entry, this introduced a typical iterator invalidation
problem, triggered by btree node splits or resorts.
Previously, dealt with this by unconditionally re-validating those
stashed pointers in the transaction commit path. This patch gets rid of
that by doing it only when needed, in bch2_trans_node_add() or
bch2_trans_node_reinit_iter().
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
bch2_btree_iter_peek_upto() in snapshots mode may need to keep a
btree_path for the insert position, not just the position of the key
we're returning. The code was incorrectly assuming this would be in the
same btree node - we were missing a bch2_btree_path_traverse() call.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
This fixes a (harmless) broken invariant in __bch2_btree_path_set_pos():
iterators to interior nodes should point to the first non whiteout.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
This switches btree_key_cache_fill() to use a btree iterator, not a
btree path, so that it can search for keys in previous snapshots.
We also add another iterator flag, BTREE_ITER_KEY_CACHE_FILL, to avoid
recursion back into the key cache.
This will allow us to re-enable the key cache for inodes in the next
patch.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
There was no reason for this to be a separate helper - we always want
the relock call that btree_trans_peek_key_cache() did.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
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>
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>
- 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>
btree_path_copy() doesn't need to call
bch2_btree_path_check_sort_fast() - the newly allocated path will always
be in the correct position, post copy; also delete some redundant
branches from __bch2_btree_path_make_mut().
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
- Don't call into bch2_encrypt_bio() when we're not encrypting
- Pull slowpath out of trans_lock_write()
- Make sure bc2h_trans_journal_res_get() gets inlined.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
- In the btree iterator code that overlays keys from the journal, we
were incorrectly specifying level=0 instead of the btree_path's
current level in a few places
- When we didn't do journal replay, we shouldn't free the journal keys:
this fixes cmd_list and cmd_dump, which run in norecovery mode
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
This moves the JOURNAL_REPLAY_DONE flag check from
bch2_trans_iter_init() to bch2_trans_init(), where we stash a copy in
btree_trans - gaining us a small performance improvement.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
checkpatch.pl gives lots of warnings that we don't want - suggested
ignore list:
ASSIGN_IN_IF
UNSPECIFIED_INT - bcachefs coding style prefers single token type names
NEW_TYPEDEFS - typedefs are occasionally good
FUNCTION_ARGUMENTS - we prefer to look at functions in .c files
(hopefully with docbook documentation), not .h
file prototypes
MULTISTATEMENT_MACRO_USE_DO_WHILE
- we have _many_ x-macros and other macros where
we can't do this
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
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>
local_clock() isn't always completely accurate - e.g. on machines with
TSC drift - but ktime_get_ns() overhead is too high, unfortunately.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
We were forgetting to count down the number of nodes to prefetch, firing
off _way_ more than intended - whoops.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
In the drop_alloc tests, we may end up calling
bch2_btree_iter_peek_slot() on an interior level that doesn't exist.
Previously, this would hit the path->uptodate assertion in
bch2_btree_path_peek_slot(); this path first checks a NULL btree node,
which is how we know we're at the end of the btree.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
The btree iterator code may allocate extra btree paths, temporarily,
that do not refer to keys being returned: we don't need to wait until
transaction restart to drop these, when they're not referenced they
should be deleted right away.
This fixes a transaction path overflow bug.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
There was a rare bug when path->locks_want was nonzero, but not
BTREE_MAX_DEPTH, where we'd return on a valid node that wasn't locked -
oops.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
This function is fairly small and only used in two places: one very hot,
the other cold, so it should definitely be inlined.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
- move slowpath code to a separate function, btree_path_overflow()
- no need to use hweight64
- copy nr_max_paths from btree_transaction_stats to btree_trans,
avoiding a data dependency in the fast path
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
This adds a helper for printing a large buffer one line at a time, to
avoid the 1k printk limit.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Most of the node_relock_fail trace events are generated from
bch2_btree_path_verify_level(), when debugcheck_iterators is enabled -
but we're not interested in these trace events, they don't indicate that
we're in a slowpath.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
