Generic data structure for explicitly tracking pending RCU items,
allowing items to be dequeued (i.e. allocate from items pending
freeing). Works with conventional RCU and SRCU, and possibly other RCU
flavors in the future, meaning this can serve as a more generic
replacement for SLAB_TYPESAFE_BY_RCU.
Pending items are tracked in radix trees; if memory allocation fails, we
fall back to linked lists.
A rcu_pending is initialized with a callback, which is invoked when
pending items's grace periods have expired. Two types of callback
processing are handled specially:
- RCU_PENDING_KVFREE_FN
New backend for kvfree_rcu(). Slightly faster, and eliminates the
synchronize_rcu() slowpath in kvfree_rcu_mightsleep() - instead, an
rcu_head is allocated if we don't have one and can't use the radix
tree
TODO:
- add a shrinker (as in the existing kvfree_rcu implementation) so that
memory reclaim can free expired objects if callback processing isn't
keeping up, and to expedite a grace period if we're under memory
pressure and too much memory is stranded by RCU
- add a counter for amount of memory pending
- RCU_PENDING_CALL_RCU_FN
Accelerated backend for call_rcu() - pending callbacks are tracked in
a radix tree to eliminate linked list overhead.
to serve as replacement backends for kvfree_rcu() and call_rcu(); these
may be of interest to other uses (e.g. SLAB_TYPESAFE_BY_RCU users).
Note:
Internally, we're using a single rearming call_rcu() callback for
notifications from the core RCU subsystem for notifications when objects
are ready to be processed.
Ideally we would be getting a callback every time a grace period
completes for which we have objects, but that would require multiple
rcu_heads in flight, and since the number of gp sequence numbers with
uncompleted callbacks is not bounded, we can't do that yet.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
New key type for the disk space accounting rewrite.
- Holds a variable sized array of u64s (may be more than one for
accounting e.g. compressed and uncompressed size, or buckets and
sectors for a given data type)
- Updates are deltas, not new versions of the key: this means updates
to accounting can happen via the btree write buffer, which we'll be
teaching to accumulate deltas.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
If a btree root or interior btree node goes bad, we're going to lose a
lot of data, unless we can recover the nodes that it pointed to by
scanning.
Fortunately btree node headers are fully self describing, and
additionally the magic number is xored with the filesytem UUID, so we
can do so safely.
This implements the scanning - next patch will rework topology repair to
make use of the found nodes.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Pull out eytzinger.c and kill eytzinger_cmp_fn. We now provide
eytzinger0_sort and eytzinger0_sort_r, which use the standard cmp_func_t
and cmp_r_func_t callbacks.
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>
32-bit arm builds emit a lot of spam like this:
fs/bcachefs/backpointers.c: In function ‘extent_matches_bp’:
fs/bcachefs/backpointers.c:15:13: note: parameter passing for argument of type ‘struct bch_backpointer’ changed in GCC 9.1
Apply the change from commit ebcc5928c5 ("arm64: Silence gcc warnings
about arch ABI drift") to fs/bcachefs/ to silence them.
Signed-off-by: Calvin Owens <jcalvinowens@gmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Add a new superblock section that contains a list of
{ minor version, recovery passes, errors_to_fix }
that is - a list of recovery passes that must be run when downgrading
past a given version, and a list of errors to silently fix.
The upcoming disk accounting rewrite is not going to be fully
compatible: we're going to have to regenerate accounting both when
upgrading to the new version, and also from downgrading from the new
version, since the new method of doing disk space accounting is a
completely different architecture based on deltas, and synchronizing
them for every jounal entry write to maintain compatibility is going to
be too expensive and impractical.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Move the slowpath (actually growing the darray) to an out-of-line
function; also, add some helpers for the upcoming btree write buffer
rewrite.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Add a new superblock section to keep counts of errors seen since
filesystem creation: we'll be addingcounters for every distinct fsck
error.
The new superblock section has entries of the for [ id, count,
time_of_last_error ]; this is intended to let us see what errors are
occuring - and getting fixed - via show-super output.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Add a new btree for long running logged operations - i.e. for logging
operations that we can't do within a single btree transaction, so that
they can be resumed if we crash.
Keys in the logged operations btree will represent operations in
progress, with the state of the operation stored in the value.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
More reorganization, this splits up io.c into
- io_read.c
- io_misc.c - fallocate, fpunch, truncate
- io_write.c
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
subvolume.c has gotten a bit large, this splits out a separate file just
for managing snapshot trees - BTREE_ID_snapshots.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Split out a new file from recovery.c for managing the list of keys we
read from the journal: before journal replay finishes the btree iterator
code needs to be able to iterate over and return keys from the journal
as well, so there's a fair bit of code here.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Split out a new file for bch_sb_field_members - we'll likely want to
move more code here in the future.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
fs-io.c is too big - time for some reorganization
- fs-dio.c: direct io
- fs-pagecache.c: pagecache data structures (bch_folio), utility code
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
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 patch adds backpointers: we now have a reverse index from device
and offset on that device (specifically, offset within a bucket) back to
btree nodes and (non cached) data extents.
The first 40 backpointers within a bucket are stored in the alloc key;
after that backpointers spill over to the next backpointers btree. This
is to help avoid performance regressions from additional btree updates
on large streaming workloads.
This patch adds all the code for creating, checking and repairing
backpointers. The next patch in the series is going to use backpointers
for copygc - finally getting rid of the need to scan all extents to do
copygc.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
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>
We have a unique lock used for controlling adding to the pagecache: the
lock has two states, where both states are shared - the lock may be held
multiple times for either state - but not both states at the same time.
This is exactly what we need for nocow mode locking, so this patch pulls
it out of fs.c into its own file.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
This module provides a fast 64bit implementation of basic statistics
functions, including mean, variance and standard deviation in both
weighted and unweighted variants, the unweighted variant has a 32bit
limitation per sample to prevent overflow when squaring.
Signed-off-by: Daniel Hill <daniel@gluo.nz>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Start to centralize some of the locking code in a new file; more locking
code will be moving here in the future.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Instead of overloading standard error codes (EINTR/EAGAIN), and defining
short lists of error codes in multiple places that potentially end up
overlapping & conflicting, we're now going to have one master list of
error codes.
Error codes are defined with an x-macro: thus we also have
bch2_err_str() now.
Also, error codes have a class field. Now, instead of checking for
errors with ==, code should use bch2_err_matches(), which returns true
if the error is equal to or a sub-error of the error class.
This means we can define unique errors for every source location where
an error is generated, which will help improve our error messages.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
This is the start of reorganizing the data IO paths. The plan is to also
break apart io.c into data_read.c and data_write.c, and migrate_write
will be renamed to the data_update path.
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>
This adds a new superblock field for persisting counters
and adds a sysfs interface in counters/ exposing these counters.
The superblock field is ignored by older versions letting us avoid
an on disk version bump.
Each sysfs file outputs a counter that tracks since filesystem
creation and a counter for the current mount session.
Signed-off-by: Daniel Hill <daniel@gluo.nz>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
This implements new persistent LRUs, to be used for buckets containing
cached data, as well as stripes ordered by time when a block became
empty.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Add a new superblock field which represents journal buckets as ranges:
also move code for the superblock journal fields to journal_sb.c.
This also reworks the code for resizing the journal to write the new
superblock before using the new journal buckets, and thus be a bit
safer.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Implement a hash table, using cuckoo hashing, for empty buckets that are
waiting on a journal commit before they can be reused.
This replaces the journal_seq field of bucket_mark, and is part of
eventually getting rid of the in memory bucket array.
We may need to make bch2_bucket_needs_journal_commit() lockless, pending
profiling and testing.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
This patch adds subvolume.c - support for the subvolumes and snapshots
btrees and related data types and on disk data structures. The next
patches will start hooking up this new code to existing code.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Do not compile the acl.o target if BCACHEFS_POSIX_ACL is not enabled.
Signed-off-by: Dan Robertson <dan@dlrobertson.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Previous varint implementation used by the inode code was not nearly as
fast as it could have been; partly because it was attempting to encode
integers up to 96 bits (for timestamps) but this meant that encoding and
decoding the length required a table lookup.
Instead, we'll just encode timestamps greater than 64 bits as two
separate varints; this will make decoding/encoding of inodes
significantly faster overall.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
This introduces a new kind of btree iterator, cached iterators, which
point to keys cached in a hash table. The cache also acts as a write
cache - in the update path, we journal the update but defer updating the
btree until the cached entry is flushed by journal reclaim.
Cache coherency is for now up to the users to handle, which isn't ideal
but should be good enough for now.
These new iterators will be used for updating inodes and alloc info (the
alloc and stripes btrees).
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
This refactoring makes the code easier to understand by separating the
bcachefs btree transactional code from the linux VFS code - but more
importantly, it's also to share code with the fuse port.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Initially forked from drivers/md/bcache, bcachefs is a new copy-on-write
filesystem with every feature you could possibly want.
Website: https://bcachefs.org
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
