For each bucket we track when the bucket became nonempty and when it
became empty again: if we can ensure that there will be no journal
flushes in the range [nonempty, empty) (possibly because they occured at
the same journal sequence number), then it's safe to reuse the bucket
without waiting for a journal commit.
This is a major performance optimization for erasure coding, where
writes are initially replicated, but the extra replicas are quickly
dropped: if those buckets are reused and overwritten without issuing a
cache flush to the underlying device, then they only cost bus bandwidth.
But there's a tricky corner case when there's multiple empty -> nonempty
-> empty transitions in quick succession, i.e. when data is getting
overwritten immediately as it's being written.
If this happens and the previous empty transition hasn't been flushed,
we need to continue tracking the previous nonempty transition - not
start a new one.
Fixing this means we now need to track both the nonempty and empty
transitions in bch_alloc_v4.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Harder to screw up if we're explicit about the range, and more correct
as journal reservations can be outstanding on multiple journal entries
simultaneously.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
When calling check_discard_freeespace_key from the allocator, we can't
repair without recursing - run it asynchronously instead.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
This fixes an assertion pop in bch2_journal_noflush_seq() - log the
error to the superblock and continue instead.
Reported-by: syzbot+85700120f75fc10d4e18@syzkaller.appspotmail.com
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
transaction commits invalidate pointers to btree values, and they also
downgrade intent locks.
This breaks the interior btree update path, which takes intent locks and
then calls into the allocator.
This isn't an ideal solution: we can't unconditionally issue a restart
after a transaction commit, because that would break other codepaths.
Reported-by: syzbot+78d82470c16a49702682@syzkaller.appspotmail.com
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Add a new parameter to bkey validate functions, and use it to improve
invalid bkey error messages: we can now print the btree and depth it
came from, or if it came from the journal, or is a btree root.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
The discard bucket fastpath previously was using its own code for
discarding buckets and clearing them in the need_discard btree, which
didn't have any of the consistency checks of the main discard path.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Factor out a common helper, need_discard_or_freespace_err(), which is
now used by both fsck and the runtime checks, and can repair.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
check_discard_freespace_key() was doing all the same checks as
try_alloc_bucket(), but with repair.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Change it to a normal fsck_err() - meaning it'll get repaired at runtime
when that's flipped on.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
alloc key validation ensures that if a bucket is in need_discard state
the sector counts are all zero - we don't have to check for that.
The NEED_INC_GEN check appears to be dead code, as well: we only see
buckets in the need_discard btree, and it's an error if they aren't in
the need_discard state.
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>
bch2_bucket_io_time_reset() doesn't need to succeed, which is why it
didn't previously retry on transaction restart - but we're now treating
these as errors.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
this one is fairly harmless since the invalidate worker will just run
again later if it needs to, but still worth fixing
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
We were checking that the alloc key was for a valid device, but not a
valid bucket.
This is the upgrade path from versions prior to bcachefs being mainlined.
Reported-by: syzbot+a1b59c8e1a3f022fd301@syzkaller.appspotmail.com
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
The fragmentation_lru field hasn't been needed since we reworked the LRU
btrees to use the btree write buffer; previously it was used to resolve
collisions, but the revised LRU btree uses the backpointer (the bucket)
as part of the key.
It should have been deleted at the time of the LRU rework; since it
wasn't, that left places for bugs to hide, in check/repair.
This fixes LRU fsck on a filesystem image helpfully provided by a user
who disappeared before I could get his name for the reported-by.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Add a counter that's incremented whenever rw devices change; this will
be used for erasure coding so that it can keep ec_stripe_head in sync
and not deadlock on a new stripe when a device it wants goes away.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
We can now correctly force-remove a device that has stripes on it; this
uses the new BCH_SB_MEMBER_INVALID sentinal value.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Use jiffies macros instead of using jiffies directly to handle wraparound.
Signed-off-by: Chen Yufan <chenyufan@vivo.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
ca->io_ref does not protect against the filesystem going way,
c->write_ref does. Much like
0b50b7313e bcachefs: Fix refcounting in discard path
the other async paths need fixing.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
bch_dev->io_ref does not protect against the filesystem going away;
bch_fs->writes does.
Thus the filesystem write ref needs to be the last ref we release.
Reported-by: syzbot+9e0404b505e604f67e41@syzkaller.appspotmail.com
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
we allow new fields to be added to existing key types, and new versions
should treat them as being zeroed; this was not handled in
alloc_v4_validate.
Reported-by: syzbot+3b2968fa4953885dd66a@syzkaller.appspotmail.com
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Comparing the wrong bpos - this was missed because normally
bucket_gens_init() runs on brand new filesystems, but this bug caused it
to overwrite bucket_gens keys with 0s when upgrading ancient
filesystems.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
On testing on an old mangled filesystem, we missed a case.
Fixes: bd864bc2d9 ("bcachefs: Fix bch2_trigger_alloc when upgrading from old versions")
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>
bch2_trigger_alloc was assuming that the new key would always be newly
created and thus always an alloc_v4 key, but - not when called from
btree_gc.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
gc_lock is now only for synchronization between check_alloc_info and
interior btree updates - nothing else
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>
Needed for online fsck; we need the trigger to initialize newly
allocated buckets and generation number changes while gc is running.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Rewrite fsck/gc for the new accounting scheme.
This adds a second set of in-memory accounting counters for gc to use;
like with other parts of gc we run all trigger in TRIGGER_GC mode, then
compare what we calculated to existing in-memory accounting at the end.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Main part of the disk accounting rewrite.
This is a wholesale rewrite of the existing disk space accounting, which
relies on percepu counters that are sharded by journal buffer, and
rolled up and added to each journal write.
With the new scheme, every set of counters is a distinct key in the
accounting btree; this fixes scaling limitations of the old scheme,
where counters took up space in each journal entry and required multiple
percpu counters.
Now, in memory accounting requires a single set of percpu counters - not
multiple for each in flight journal buffer - and in the future we'll
probably also have counters that don't use in memory percpu counters,
they're not strictly required.
An accounting update is now a normal btree update, using the btree write
buffer path. At transaction commit time, we apply accounting updates to
the in memory counters, which are percpu counters indexed in an
eytzinger tree by the accounting key.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Add a separate counter to bch_alloc_v4 for amount of striped data; this
lets us separately track striped and unstriped data in a bucket, which
lets us see when erasure coding has failed to update extents with stripe
pointers, and also find buckets to continue updating if we crash mid way
through creating a new stripe.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
We need to make sure we're not missing any fragmenation entries in the
LRU BTREE after repairing ALLOC BTREE
Also, use the new bch2_btree_write_buffer_maybe_flush() helper; this was
only working without it before since bucket invalidation (usually)
wasn't happening while fsck was running.
Co-developed-by: Daniel Hill <daniel@gluo.nz>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
There's no reason for discards to be single threaded across all devices;
this will improve performance on multi device setups.
Additionally, making them per-device simplifies the refcounting on
bch_dev->io_ref; we now hold it for the duration that the discard path
is running, which fixes a race between the discard path and device
removal.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Incorrect bucket state transition in the discard path; when incrementing
a bucket's generation number that had already been discarded, we were
forgetting to check if it should be need_gc_gens, not free.
This was caught by the .invalid checks in the transaction commit path,
causing us to go emergency read only.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
LRUs only have 48 bits for the time field (i.e. LRU order); thus we need
overflow checks and guards.
Reported-by: syzbot+df3bf3f088dcaa728857@syzkaller.appspotmail.com
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
We can't discard a bucket while it's still open; this needs the
bucket_is_open_safe() version, which takes the open_buckets lock.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
We're about to start using bch_validate_flags for superblock section
validation - it's no longer bkey specific.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
