We need to allow filesystems with metadata from newer versions to be
mountable and usable by older versions.
This patch enables us to roll out new btrees without a new major version
number; we can now handle btree roots for unknown btree types.
The unknown btree roots will be retained, and fsck (including
backpointers) will check them, the same as other btree types.
We add a dynamic array for the extra, unknown btree roots, in addition
to the fixed size btree root array, and add new helpers for looking up
btree roots.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Fix a bug where bch2_btree_node_get() might call bch2_trans_unlock() (in
fill) without calling bch2_trans_relock(); this is a bug when it's done
in the core btree code.
Also, twea bch2_btree_node_mem_alloc() to drop btree locks before doing
a blocking memory allocation.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
As suggested by Linus, this drops the six_lock_state union in favor of
raw bitmasks.
On the one hand, bitfields give more type-level structure to the code.
However, a significant amount of the code was working with
six_lock_state as a u64/atomic64_t, and the conversions from the
bitfields to the u64 were deemed a bit too out-there.
More significantly, because bitfield order is poorly defined (#ifdef
__LITTLE_ENDIAN_BITFIELD can be used, but is gross), incrementing the
sequence number would overflow into the rest of the bitfield if the
compiler didn't put the sequence number at the high end of the word.
The new code is a bit saner when we're on an architecture without real
atomic64_t support - all accesses to lock->state now go through
atomic64_*() operations.
On architectures with real atomic64_t support, we additionally use
atomic bit ops for setting/clearing individual bits.
Text size: 7467 bytes -> 4649 bytes - compilers still suck at
bitfields.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
six_lock_pcpu_alloc() is an unsafe interface: it's not safe to allocate
or free the percpu reader count on an existing lock that's in use, the
only safe time to allocate percpu readers is when the lock is first
being initialized.
This patch adds a flags parameter to six_lock_init(), and instead of
six_lock_pcpu_free() we now expose six_lock_exit(), which does the same
thing but is less likely to be misused.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
This adds private error codes for most (but not all) of our ENOMEM uses,
which makes it easier to track down assorted allocation failures.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
This fixes some confusion in the lockdep code due to initializing btree
node/key cache locks with the same lockdep key, but different names.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Soon, __bch2_btree_node_write() is going to require a btree_trans: zoned
device support is going to require a new allocation for every btree node
write. This is a bit of prep work.
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 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>
Btree nodes shouldn't have their accessed bit set when entering the
btree cache by being read in from disk - this fixes linear scans
thrashing the cache.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Standard splitting out of the slow path from the fast path of a
function. We may follow this up in another patch with inlining the fast
path into btree_iter.c.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
b->write_type needs to be set atomically with setting the
btree_node_need_write flag, so move it into b->flags.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
This replaces sysfs btree_avg_write_size with btree_write_stats, which
now breaks out statistics by the source of the btree write.
Btree writes that are too small are a source of inefficiency, and
excessive btree resort overhead - this will let us see what's causing
them.
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>
Appending new nodes to the end of the list means we're more likely to
evict old entries when btree_cache_scan() is started.
Signed-off-by: Daniel Hill <daniel@gluo.nz>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
We're still seeing OOM issues caused by the btree node cache shrinker
not sufficiently freeing memory: thus, this patch changes the shrinker
to not exit if __GFP_FS was not supplied.
Instead, tweak btree node memory allocation so that we never invoke
memory reclaim while holding the btree node cache lock.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
In the future, with the new deadlock cycle detector, we won't be using
bare six_lock_* anymore: lock wait entries will all be embedded in
btree_trans, and we will need a btree_trans context whenever locking a
btree node.
This patch plumbs a btree_trans to the few places that need it, and adds
two new locking functions
- btree_node_lock_nopath, which may fail returning a transaction
restart, and
- btree_node_lock_nopath_nofail, to be used in places where we know we
cannot deadlock (i.e. because we're holding no other locks).
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Also, do some reorganizing/renaming, convert atomic counters in bch_fs
to persistent counters, and add a few missing counters.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
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>
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>
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>
This converts bcachefs to the modern printbuf interface/implementation,
synced with the version to be submitted upstream.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
In the future printbufs will be mempool-ified, so we shouldn't be using
more than one at a time if we don't have to.
This also fixes an extra trailing newline.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
This behavior dates from the early, early days of bcache, and upon
further delving appears to not make any sense. The shrinker only works
in terms of 'objects' of unknown size; normalizing to pages only had the
effect of changing the batch size, which we could do directly - if we
wanted; we probably don't. Normalizing to pages meant our batch size was
very small, which seems to have been keeping us from doing as much
shrinking as we should be under heavy memory pressure; this patch
appears to alleviate some OOMs we've been seeing.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Six locks have a percpu mode, which we use for interior btree nodes, as
well as btree key cache keys for the subvolumes btree. We've been
switching locks back and forth between percpu and non percpu mode as
needed, but it turns out this is racy - when we're reusing an existing
node, other threads could be attempting to lock it while we're switching
it between modes.
This patch fixes this by never switching 'struct btree' between the two
modes, and instead segragating them between two different freed lists.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
This is prep work for the next patch, which is going to fix our usage of
the percpu mode of six locks by never switching struct btree between the
two modes - which means we need separate freed lists.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Previously, when bch2_btree_cache_scan() attempted to reclaim a node but
failed (because trylock failed, because it was dirty, etc.), it would
count that against the number of nodes it was scanning and attempting to
free. This patch changes that behaviour, so that now we only count nodes
that we then don't free if they have the accessed bit (which we also
clear).
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Checking btree_node_may_write() isn't atomic with the other btree flags,
dirty and need_write in particular. There was a rare race where we'd
unblock a node from writing while __btree_node_flush() was setting
need_write, and no thread would notice that the node was now both able
to write and needed to be written.
Fix this by adding btree node flags for will_make_reachable and
write_blocked that can be checked in the cmpxchg loop in
__bch2_btree_node_write.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
btree_node_write_if_need() kicks off a btree node write only if
need_write is set; this makes the locking easier to reason about by
moving the check into the cmpxchg loop in __bch2_btree_node_write().
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
This patch changes printbufs dynamically allocate and reallocate a
buffer as needed. Stack usage has become a bit of a problem, and a major
cause of that has been static size string buffers on the stack.
The most involved part of this refactoring is that printbufs must now be
exited with printbuf_exit().
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
The error code when we fail to allocate a node in the btree node cache
doesn't make it to bch2_btree_path_traverse_all(). Instead, we need to
stash a flag in btree_trans so we know we have to take the cannibalize
lock.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
This improves the transaction restart tracepoints - adding distinct
tracepoints for all the locations and reasons a transaction might have
been restarted, and ensures that there's a tracepoint for every
transaction restart.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
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>
This is to help with diagnosing why the btree node can doesn't seem to
be shrinking - we've had issues in the past with granularity/batch size,
since btree nodes are so big.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
This puts a load behind some branches before where it's used, so that it
can execute in parallel with other loads.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
When attempting to free btree nodes, we might not be able to free all
the nodes that were requested. But the code was looping until it had
freed _all_ the nodes requested, when it should have only been
attempting to free nr nodes.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
This patch checks b->hash_val before attempting to lock the node in the
btree, which makes it more equivalent to the "lookup in hash table"
path - and potentially avoids an unnecessary transaction restart if
btree_node_mem_ptr(k) no longer points to the node we want.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
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>
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>
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>
On transaction restart iterators won't be locked anymore - make sure
we're always checking for errors.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
bch2_btree_node_ptr_v2 has a field for stashing a pointer to the in
memory btree node; this is safe because we clear this field when reading
in nodes from disk and we never free in memory btree nodes - but, we
have bug reports that indicate something might be faulty with this
optimization, so let's add an option for it.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
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>
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>
This is a performance improvement by removing the need to wait for the
in flight btree write to complete before kicking one off, which is going
to be needed to avoid a performance regression with the upcoming patch
to update btree ptrs after every btree write.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
This is something we've attempted to stick to for quite some time, as it
helps guarantee filesystem latency - but there's a few remaining paths
that this patch fixes.
This is also necessary for an upcoming patch to update btree pointers
after every btree write - since the btree write completion path will now
be doing btree operations.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
As a rule we don't want to be holding btree locks while submitting IO -
this will improve overall filesystem latency.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
This patch adds some new tracepoints to the btree iterator code, and
adds new fields to the existing tracepoints - primarily for the iterator
position.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
This was a major oversight - this means under memory pressure we can end
up reading in a btree node, then having it evicted before we get to use
it.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
There was a bug that led to duplicate btree node pointers being inserted
at the wrong level. The new topology repair code can fix that, except
that the btree cache code gets confused when we read in a btree node
from the pointer that was at the wrong level. This patch evicts nodes
that we're deleting to, which nicely solves the problem.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Calling mmap() directly is much better than malloc() then mprotect(), we
end up with much less address space fragmentation.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
This replaces an assertion in the btree merge path with a
bch2_inconsistent_error() - fsck will fix it.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
bch2_btree_verify() verifies that the btree node on disk matches what we
have in memory. This patch changes it to verify every replica, and also
fixes it for interior btree nodes - there's a mem_ptr field which is
used as a scratch space and needs to be zeroed out for comparing with
what's on disk.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
The previous patch that fixed btree nodes being written too aggressively
now meant that we weren't sorting btree node bsets optimally - this
patch fixes that.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
This patch reworks the btree node merge path to use a second btree
iterator to get the sibling node - which means
bch2_btree_iter_get_sibling() can be deleted. Also, it uses
bch2_btree_iter_traverse_all() if necessary - which means it should be
more reliable. We don't currently even try to make it work when
trans->nounlock is set - after a BTREE_INSERT_NOUNLOCK transaction
commit, hopefully this will be a worthwhile tradeoff.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
This patch starts treating the bpos.snapshot field like part of the key
in the btree code:
* bpos_successor() and bpos_predecessor() now include the snapshot field
* Keys in btrees that will be using snapshots (extents, inodes, dirents
and xattrs) now always have their snapshot field set to U32_MAX
The btree iterator code gets a new flag, BTREE_ITER_ALL_SNAPSHOTS, that
determines whether we're iterating over keys in all snapshots or not -
internally, this controlls whether bkey_(successor|predecessor)
increment/decrement the snapshot field, or only the higher bits of the
key.
We add a new member to struct btree_iter, iter->snapshot: when
BTREE_ITER_ALL_SNAPSHOTS is not set, iter->pos.snapshot should always
equal iter->snapshot, which will be 0 for btrees that don't use
snapshots, and alsways U32_MAX for btrees that will use snapshots
(until we enable snapshot creation).
This patch also introduces a new metadata version number, and compat
code for reading from/writing to older versions - this isn't a forced
upgrade (yet).
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
With snapshots, we're going to need to differentiate between comparisons
that should and shouldn't include the snapshot field. bpos_cmp is now
the comparison function that does include the snapshot field, used by
core btree code.
Upper level filesystem code generally does _not_ want to compare against
the snapshot field - that code wants keys to compare as equal even when
one of them is in an ancestor snapshot.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
It was counting nodes on the freed list that it skips - because we want
to leave a few so that btree splits don't touch the allocator - as nodes
that it touched, meaning that if it was called with <= 3 nodes to
reclaim, and those nodes were on the freed list, it would never do any
work.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
bch2_btree_node_get_noiter() isn't used from the btree iterator code,
which retries with the btree node cache cannibalize lock held on
-ENOMEM, so we should do it ourself if necessary.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
When we walk the btrees during recovery, part of that is checking that
btree topology is correct: for every interior btree node, its child
nodes should exactly span the range the parent node covers.
Previously, we had checks for this, but not repair code. Now that we
have the ability to do btree updates during initial GC, this patch adds
that repair code.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
bch2_btree_and_journal_walk() walks the btree overlaying keys from the
journal; it was introduced so that we could read in the alloc btree
prior to journal replay being done, when journalling of updates to
interior btree nodes was introduced.
But it didn't have btree node prefetching, which introduced a severe
regression with mount times, particularly on spinning rust. This patch
implements btree node prefetching for the btree + journal walk,
hopefully fixing that.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
More debugging info is always a good thing.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
With various newer key types - stripe keys, inline data extents - the
old approach of calculating the maximum size of the value is becoming
more and more error prone. Better to switch to bkey_on_stack, which can
dynamically allocate if necessary to handle any size bkey.
In particular we also want to get rid of BKEY_EXTENT_VAL_U64s_MAX.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
This lets us improve journal reclaim, so that it now tries to make sure
no more than 3/4s of the btree node cache and btree key cache are dirty
- ensuring the shrinkers can free memory.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
It's not used much anymore, the module paramter interface is better.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
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>
There was a bug where bch2_trans_update() would incorrectly delete a
pending update where the new update did not actually overwrite the
existing update, because we were incorrectly using BTREE_ITER_TYPE when
sorting pending btree updates.
This affects the pending patch to use cached iterators for inode
updates.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
vfree() can allocate memory, so we need to call memalloc_nofs_save().
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
We can't allocate memory with GFP_FS while holding the btree cache lock,
and vfree() can allocate memory.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
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>
The btree cache lock is needed for reclaiming from the btree node cache,
and memory allocation can potentially spin and sleep (for 100 ms at a
time), so.. don't do that.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
bch2_btree_node_mem_alloc() uses memalloc_nofs_save()/GFP_NOFS, but
GFP_NOFS does include __GFP_IO - oops. We used to use GFP_NOIO, but as
we're a filesystem now GFP_NOFS makes more sense now and is looser.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
There was a bad interaction with bch2_btree_iter_set_pos_same_leaf(),
which can leave a btree node locked that is just outside iter->pos,
breaking the lock ordering checks in __bch2_btree_node_lock(). Ideally
we should get rid of this corner case, but for now fix it locally with
verbose comments.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Previously, BTREE_ID_INODES was special - inodes were indexed by the
inode field, which meant the offset field of struct bpos wasn't used,
which led to special cases in e.g. the btree iterator code.
Now, inodes in the inodes btree are indexed by the offset field.
Also: prevously min_key was special for extents btrees, min_key for
extents would equal max_key for the previous node. Now, min_key =
bkey_successor() of the previous node, same as non extent btrees.
This means we can completely get rid of
btree_type_sucessor/predecessor.
Also make some improvements to the metadata IO validate/compat code.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
This is partly prep work for introducing bch_btree_ptr_v2, but it'll
also be a bit of a performance boost by moving the full key out of the
hot part of struct btree.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
