When allocating new btree nodes, we were leaving them on the freeable
list - unlocked - allowing them to be reclaimed: ouch.
Additionally, bch2_btree_node_free_never_used() ->
bch2_btree_node_hash_remove was putting it on the freelist, while
bch2_btree_node_free_never_used() was putting it back on the btree
update reserve list - ouch.
Originally, the code was written to always keep btree nodes on a list -
live or freeable - and this worked when new nodes were kept locked.
But now with the cycle detector, we can't keep nodes locked that aren't
tracked by the cycle detector; and this is fine as long as they're not
reachable.
We also have better and more robust leak detection now, with memory
allocation profiling, so the original justification no longer applies.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
If a btree split picks a pivot that's being deleted by a btree node
merge, we're going to have problems.
Fix this by checking if the pivot is being deleted, the same as we check
for deletions in journal replay keys.
Found by single_devic.ktest small_nodes.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Using commit_do() to call alloc_sectors_start_trans() breaks when we're
randomly injecting transaction restarts - the restart in the commit
causes us to leak the lock that alloc_sectorS_start_trans() takes.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
In backpointers fsck, we do a seqential scan of one btree, and check
references to another: extents <-> backpointers
Checking references generates random lookups, so we want to pin that
btree in memory (or only a range, if it doesn't fit in ram).
Previously, this was done with a simple check in the shrinker - "if
btree node is in range being pinned, don't free it" - but this generated
OOMs, as our shrinker wasn't well behaved if there was less memory
available than expected.
Instead, we now have two different shrinkers and lru lists; the second
shrinker being for pinned nodes, with seeks set much higher than normal
- so they can still be freed if necessary, but we'll prefer not to.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
This adds mount options for specifying recovery passes to run, or
exclude; the immediate need for this is that backpointers fsck is having
trouble completing, so we need a way to skip it.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
We rely on the trans->locked to know if a trans has nodes locked for
assertions about deadlocks; there can't be more than one trans in the
same process that is locked.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
We weren't always so strict about trans->locked state - but now we are,
and new assertions are shaking some bugs out.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
bkey_fsck_err() was added as an interface that looks like fsck_err(),
but previously all it did was ensure that the appropriate error counter
was incremented in the superblock.
This is a cleanup and bugfix patch that converts it to a wrapper around
fsck_err(). This is needed to fix an issue with the upgrade path to
disk_accounting_v3, where the "silent fix" error list now includes
bkey_fsck errors; fsck_err() handles this in a unified way, and since we
need to change printing of bkey fsck errors from the caller to the inner
bkey_fsck_err() calls, this ends up being a pretty big change.
Als,, rename .invalid() methods to .validate(), for clarity, while we're
changing the function signature anyways (to drop the printbuf argument).
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
fsck_err() now optionally takes a btree_trans; if the current thread has
one, it is required that it be passed.
The next patch will use this to unlock when waiting for user input.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Use try_cmpxchg() family of functions instead of
cmpxchg (*ptr, old, new) == old. x86 CMPXCHG instruction returns
success in ZF flag, so this change saves a compare after cmpxchg
(and related move instruction in front of cmpxchg).
Also, try_cmpxchg() implicitly assigns old *ptr value to "old" when
cmpxchg fails. There is no need to re-read the value in the loop.
No functional change intended.
Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Cc: Brian Foster <bfoster@redhat.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Add a pretty printer so the btree reserve cache can be seen in sysfs; as
it pins open_buckets we need it for tracking down open_buckets issues.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
We're starting to be more strict about transaction locked state, and
multiple transactions in a task.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
We're about to add new asserts for btree_trans locking consistency, and
part of that requires that aren't using the btree_trans while it's
unlocked.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Combine iter/update/trigger/str_hash flags into a single enum, and
x-macroize them for a to_text() function later.
These flags are all for a specific iter/key/update context, so it makes
sense to group them together - iter/update/trigger flags were already
given distinct bits, this cleans up and unifies that handling.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Fix another deadlock related to the merge path; previously, we switched
to always running merges at a lower watermark (because they are
noncritical); but when we run at a lower watermark we also need to run
nonblocking or we've introduced a new deadlock.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Reported-and-tested-by: s@m-h.ug
This adds a small (64 bit) per-device bitmap that tracks ranges that
have btree nodes, for accelerating btree node scan if it is ever needed.
- New helpers, bch2_dev_btree_bitmap_marked() and
bch2_dev_bitmap_mark(), for checking and updating the bitmap
- Interior btree update path updates the bitmaps when required
- The check_allocations pass has a new fsck_err check,
btree_bitmap_not_marked
- New on disk format version, mi_btree_mitmap, which indicates the new
bitmap is present
- Upgrade table lists the required recovery pass and expected fsck error
- Btree node scan uses the bitmap to skip ranges if we're on the new
version
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
There's been a bug in the btree write buffer where it wasn't triggering
btree node merges - and leaving behind a bunch of nearly empty btree
nodes.
Then during journal replay, when updates to the backpointers btree
aren't using the btree write buffer (because we require synchronization
with journal replay), we end up doing those merges all at once.
Then if it's the interior update path running them, we deadlock because
those run with the highest watermark.
There's no real need for the interior update path to be doing btree node
merges; other code paths can handle that at lower watermarks.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
This fixes a deadlock where the interior update path during journal
replay ends up doing a ton of merges on the backpointers btree, and
deadlocking.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
It turns out - btree splits happen with the rest of the transaction
still locked, to avoid unnecessary restarts, which means using nofail
doesn't work here - we can deadlock.
Fortunately, we now have the ability to return errors here.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
One btree update might have terminated in a node update, and then while
it is in flight another btree update might free that original node.
This race has to be handled in btree_update_nodes_written() - we were
missing a READ_ONCE().
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
"bcachefs; Fix deadlock in bch2_btree_update_start()" was a significant
performance regression (nearly 50%) on multithreaded random writes with
fio.
The reason is that the journal watermark checks multiple things,
including the state of the btree write buffer, and on multithreaded
update heavy workloads we're bottleneked on write buffer flushing - we
don't want kicknig off btree updates to depend on the state of the write
buffer.
This isn't strictly correct; the interior btree update path does do
write buffer updates, but it's a tiny fraction of total accounting
updates and we're more concerned with space in the journal itself.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
This adds a new watermark, higher priority than BCH_WATERMARK_reclaim,
for interior btree updates. We've seen a deadlock where journal replay
triggers a ton of btree node merges, and these use up all available open
buckets and then interior updates get stuck.
One cause of this is that we're currently lacking btree node merging on
write buffer btrees - that needs to be fixed as well.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
We've grown a fair amount of code for managing recovery passes; tracking
which ones we're running, which ones need to be run, and flagging in the
superblock which ones need to be run on the next recovery.
So it's worth splitting out into its own file, this code is pretty
different from the code in recovery.c.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
When we haven't yet allocated any btree nodes for a given btree, we
first need to call the regular split path to allocate one.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
When dropping keys now outside a now because we're changing the node
min/max, we need to redo the node's accounting as well.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Consolidate bch2_gc_check_topology() and btree_node_interior_verify(),
and replace them with an improved version,
bch2_btree_node_check_topology().
This checks that children of an interior node correctly span the full
range of the parent node with no overlaps.
Also, ensure that topology repairs at runtime are always a fatal error;
in particular, this adds a check in btree_iter_down() - if we don't find
a key while walking down the btree that's indicative of a topology error
and should be flagged as such, not a null ptr deref.
Some checks in btree_update_interior.c remaining BUG_ONS(), because we
already checked the node for topology errors when starting the update,
and the assertions indicate that we _just_ corrupted the btree node -
i.e. the problem can't be that existing on disk corruption, they
indicate an actual algorithmic bug.
In the future, we'll be annotating the fsck errors list with which
recovery pass corrects them; the open coded "run explicit recovery pass
or fatal error" in bch2_btree_node_check_topology() will in the future
be done for every fsck_err() call.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
BCH_TRANS_COMMIT_journal_reclaim with watermark != BCH_WATERMARK_reclaim
means nonblocking, and we need the journal_res_get() in
btree_update_start() to respect that.
In a future refactoring we'll be deleting
BCH_TRANS_COMMIT_journal_reclaim and replacing it with an explicit
BCH_TRANS_COMMIT_nonblocking.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
This fixes a deadlock due to using btree_interior_update_worker for non
interior updates - async btree node rewrites were blocking, and then
blocking other interior updates.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
