This adds support for nocow mode, where we do writes in-place when
possible. Patch components:
- New boolean filesystem and inode option, nocow: note that when nocow
is enabled, data checksumming and compression are implicitly disabled
- To prevent in-place writes from racing with data moves
(data_update.c) or bucket reuse (i.e. a bucket being reused and
re-allocated while a nocow write is in flight, we have a new locking
mechanism.
Buckets can be locked for either data update or data move, using a
fixed size hash table of two_state_shared locks. We don't have any
chaining, meaning updates and moves to different buckets that hash to
the same lock will wait unnecessarily - we'll want to watch for this
becoming an issue.
- The allocator path also needs to check for in-place writes in flight
to a given bucket before giving it out: thus we add another counter
to bucket_alloc_state so we can track this.
- Fsync now may need to issue cache flushes to block devices instead of
flushing the journal. We add a device bitmask to bch_inode_info,
ei_devs_need_flush, which tracks devices that need to have flushes
issued - note that this will lead to unnecessary flushes when other
codepaths have already issued flushes, we may want to replace this with
a sequence number.
- New nocow write path: look up extents, and if they're writable write
to them - otherwise fall back to the normal COW write path.
XXX: switch to sequence numbers instead of bitmask for devs needing
journal flush
XXX: ei_quota_lock being a mutex means bch2_nocow_write_done() needs to
run in process context - see if we can improve this
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
This ensures that failure to read a btree node error is treated as a
topology error, and returns the correct error so that the topology
repair pass will be run.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
The btree node read path has the ability to kick off an asynchronous
btree node rewrite if we saw and corrected an error. Previously this was
only used for errors that caused one of the replicas to be unusable -
this patch plumbs it through to all error paths, so that normal fsck
errors can be corrected.
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>
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 factors out a properly-documented helper for deciding when we want
to sort a btree node with MAX_BSETS bsets down to a single bset.
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>
In order to avoid locking all btree nodes up to the root for btree node
splits, we're going to have to introduce a new error path into
bch2_btree_insert_node(); this mean we can't have done any writes or
modified global state before that point.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
We've seen long error messages get truncated here, so convert to the new
bch2_print_string_as_lines().
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>
Topology repair may change btree node min/max keys: when it does so, we
need to always rebuild eytzinger search trees because nodes directly
depend on those values.
This fixes a bug found by the 'kill_btree_node' test, where we'd pop an
assertion in bch2_bset_search_linear().
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
b->written wasn't being reset to 0 in the btree node read retry path,
causing decrypting & validation of previously read bsets to not be
re-run - ouch.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
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>
We were forgetting to clear the read_in_flight flag - oops. This also
fixes it to not call bch2_fatal_error() before topology repair has had a
chance to do its thing.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Right now, we print an error message on btree node read error, and we
print that we're retrying, but we don't explicitly say if the retry
succeeded - this makes things a little clearer.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Bkeys have gotten a lot bigger since this code was written and now are
often formatted across multiple lines - while the reason a bkey is
invalid will still be short and fit on a single line. This patch prints
the error bfore the bkey, making it a bit more readable.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
We're seeing occasional firings of the assertion in the key cache
shutdown code that nr_dirty == 0, which means we must sometimes be doing
transaction commits after we've gone read only.
Cleanups & changes:
- BCH_FS_ALLOC_CLEAN renamed to BCH_FS_CLEAN_SHUTDOWN
- new helper bch2_btree_interior_updates_flush(), which returns true if
it had to wait
- bch2_btree_flush_writes() now also returns true if there were btree
writes in flight
- __bch2_fs_read_only now checks if btree writes were in flight in the
shutdown loop: btree write completion does a transaction update, to
update the pointer in the parent node
- assert that !BCH_FS_CLEAN_SHUTDOWN in __bch2_trans_commit
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
We now pass a rw argument to .key_invalid methods so they can trigger
assertions for updates but not on existing keys. We shouldn't trigger
these extra assertions in journal replay - this patch changes the
transaction commit path accordingly.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
This adds a new parameter to .key_invalid() methods for whether the key
is being read or written; the idea being that methods can do more
aggressive checks when a key is newly created and being written, when we
wouldn't want to delete the key because of those checks.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
This adds two new btrees for the upcoming allocator rewrite: an extents
btree of free buckets, and a btree for buckets awaiting discards.
We also add a new trigger for alloc keys to keep the new btrees up to
date, and a compatibility path to initialize them on existing
filesystems.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Now we've got strings for metadata versions - this changes
bch2_sb_to_text() and our mount log message to use it.
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>
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>
There was a rare recursive locking bug, in __bch2_btree_node_write()
nowrite path -> btree_node_write_done(), in the path that kicks off
another write.
This splits out an inner __btree_node_write_done() that expects to be
run with the btree node lock held.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
In sysfs, files can only output at most PAGE_SIZE. This is a problem for
debug info that needs to list an arbitrary number of times, and because
of this limit some of our debug info has been terser and harder to read
than we'd like.
This patch moves info about journal pins and cached btree nodes to
debugfs, and greatly expands and improves the output we return.
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>
On btree node read error, it's helpful to see what we were trying to
read - was it all zeroes?
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Apparently it actually is possible for crypto_skcipher_encrypt() to
return an error - not sure why that would be - but we need to replace
our assertion with actual error handling.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
- Add a shim uuid_unparse_lower() in the kernel, since %pU doesn't work
in userspace
- We don't need to print the bcachefs: or the filesystem name prefix in
userspace
- Improve a few error messages
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
This adds flags for options that must be a power of two (block size and
btree node size), and options that are stored in the superblock as a
power of two (encoded extent max).
Also: options are now stored in memory in the same units they're
displayed in (bytes): we now convert when getting and setting from the
superblock.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
The main function of bch2_sort_repack_merge() was to call .key_normalize
on every key, which drops stale (cached) pointers - it hasn't actually
merged extents in quite some time.
But bch2_gc_gens() now works on individual keys - we used to gc old gens
by rewriting entire btree nodes. With that gone, there's no need for
internal btree code to be calling .key_normalize anymore.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
This fixes some compiler warnings that only trigger in userspace - dead
code, a maybe uninitialed variable, a maybe null ptr passed to printk.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
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>
Add a field to struct bset for the sector offset within the btree node
where it was written.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
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>
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>
