bcachefs: bch_fs_usage_base

Split out base filesystem usage into its own type; prep work for
breaking up bch2_trans_fs_usage_apply().

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

bcachefs: Kill dev_usage->buckets_ec

This counter is redundant; it's simply the sum of BCH_DATA_stripe and
BCH_DATA_parity buckets.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

bcachefs: Fragmentation LRU

Now that we have much more efficient updates to the LRU btree, this
patch adds a new LRU that indexes buckets by fragmentation.

This means copygc no longer has to scan every bucket to find buckets
that need to be evacuated.

Changes:
- A new field in bch_alloc_v4, fragmentation_lru - this corresponds to
the bucket's position in the fragmentation LRU. We add a new field
for this instead of calculating it as needed because we may make the
fragmentation LRU optional; this field indicates whether a bucket is
on the fragmentation LRU.

Also, zoned devices will introduce variable bucket sizes; explicitly
recording the LRU position will be safer for them.

- A new copygc path for using the fragmentation LRU instead of
scanning every bucket and building up an in-memory heap.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

bcachefs: Copygc now uses backpointers

Previously, copygc needed to walk the entire extents & reflink btrees to
find extents that needed to be moved.

Now that we have backpointers, this patch implements
bch2_evacuate_bucket() in the move code, which copygc now uses for
evacuating mostly empty buckets.

Also, thanks to the new backpointers code, copygc can now move btree
nodes.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

bcachefs: Fold bucket_state in to BCH_DATA_TYPES()

Previously, we were missing accounting for buckets in need_gc_gens and
need_discard states. This matters because buckets in those states need
other btree operations done before they can be used, so they can't be
conuted when checking current number of free buckets against the
allocation watermark.

Also, we weren't directly counting free buckets at all. Now, data type 0
== BCH_DATA_free, and free buckets are counted; this means we can get
rid of the separate (poorly defined) count of unavailable buckets.

This is a new on disk format version, with upgrade and fsck required for
the accounting changes.

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

bcachefs: Kill struct bucket_mark

This switches struct bucket to using a lock, instead of cmpxchg. And now
that the protected members no longer need to fit into a u64, we can
expand the sector counts to 32 bits.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

bcachefs: Kill main in-memory bucket array

All code using the in-memory bucket array, excluding GC, has now been
converted to use the alloc btree directly - so we can finally delete it.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

bcachefs: Kill allocator threads & freelists

Now that we have new persistent data structures for the allocator, this
patch converts the allocator to use them.

Now, foreground bucket allocation uses the freespace btree to find
buckets to allocate, instead of popping buckets off the freelist.

The background allocator threads are no longer needed and are deleted,
as well as the allocator freelists. Now we only need background tasks
for invalidating buckets containing cached data (when we are low on
empty buckets), and for issuing discards.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

bcachefs: KEY_TYPE_alloc_v4

This introduces a new alloc key which doesn't use varints. Soon we'll be
adding backpointers and storing them in alloc keys, which means our
pack/unpack workflow for alloc keys won't really work - we'll need to be
mutating alloc keys in place.

Instead of bch2_alloc_unpack(), we now have bch2_alloc_to_v4() that
converts older types of alloc keys to v4 if needed.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

bcachefs: bch2_gc_gens() no longer uses bucket array

Like the previous patches, this converts bch2_gc_gens() to use the alloc
btree directly, and private arrays of generation numbers for its own
recalculation of oldest_gen.

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

bcachefs: New data structure for buckets waiting on journal commit

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>

bcachefs: New in-memory array for bucket gens

The main in-memory bucket array is going away, but we'll still need to
keep bucket generations in memory, at least for now - ptr_stale() needs
to be an efficient operation.

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

bcachefs: Fix bch2_trans_mark_dev_sb()

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

bcachefs: Kill bch2_fs_usage_scratch_get()

This is an important cleanup, eliminating an unnecessary copy in the
transaction commit path.

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

bcachefs: Persist 64 bit io clocks

Originally, bcachefs - going back to bcache - stored, for each bucket, a
16 bit counter corresponding to how long it had been since the bucket
was read from. But, this required periodically rescaling counters on
every bucket to avoid wraparound. That wasn't an issue in bcache, where
we'd perodically rewrite the per bucket metadata all at once, but in
bcachefs we're trying to avoid having to walk every single bucket.

This patch switches to persisting 64 bit io clocks, corresponding to the
64 bit bucket timestaps introduced in the previous patch with
KEY_TYPE_alloc_v2.

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

bcachefs: KEY_TYPE_alloc_v2

This introduces a new version of KEY_TYPE_alloc, which uses the new
varint encoding introduced for inodes. This means we'll eventually be
able to support much larger bucket sizes (for SMR devices), and the
read/write time fields are expanded to 64 bits - which will be used in
the next patch to get rid of the periodic rescaling of those fields.

Also, for buckets that are members of erasure coded stripes, this adds
persistent fields for the index of the stripe they're members of and the
stripe redundancy. This is part of work to get rid of having to scan and
read into memory the alloc and stripes btrees at mount time.

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

bcachefs: Refactor dev usage

This is to make it more amenable for serialization.

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

bcachefs: Don't drop replicas when copygcing ec data

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

bcachefs: Change copygc to consider bucket fragmentation

When devices have different sized buckets this is more correct.

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

bcachefs: Make copygc thread global

Per device copygc threads don't move data to different devices and they
make fragmentation works - they don't make much sense anymore.

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

bcachefs: Track sectors of erasure coded data

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

bcachefs: Implement a new gc that only recalcs oldest gen

Full mark and sweep gc doesn't (yet?) work with the new btree key cache
code, but it also blocks updates to interior btree nodes for the
duration and isn't really necessary in practice; we aren't currently
attempting to repair errors in allocation info at runtime.

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

bcachefs: Make replicas_delta_list smaller

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

bcachefs: Refactor bch2_alloc_write()

Major simplification - gets rid of the need for marking buckets as
dirty, instead we write buckets if the in memory mark is different from
what's in the btree.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

bcachefs: Don't use a fixed size buffer for fs_usage_deltas

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

bcachefs: bch2_trans_mark_update()

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

bcachefs: Write out fs usage consistently

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

bcachefs: add ability to run gc on metadata only

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

bcachefs: Add a mechanism for blocking the journal

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

bcachefs: Fix oldest_gen handling

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

bcachefs: Fix check for if extent update is allocating

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

bcachefs: Include summarized counts in fs_usage

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

bcachefs: refactor bch_fs_usage

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

bcachefs: move dirty into bucket_mark

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

bcachefs: Add new alloc fields

prep work for persistent alloc info

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

bcachefs: Track nr_inodes with the key marking machinery

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

bcachefs: gc now operates on second set of bucket marks

This means we can now use gc to verify the allocation information -
important for testing persistant alloc info

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

bcachefs: Erasure coding

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

bcachefs: Change how replicated data is accounted

Due to compression, the different replicas of a replicated extent don't
necessarily have to take up the same amount of space - so replicated
data sector counts shouldn't be stored divided by the number of
replicas.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

bcachefs: Account for internal fragmentation better

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

bcachefs: kill s_alloc, use bch_data_type

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

bcachefs: don't call bch2_bucket_seq_cleanup from journal_buf_switch

journal_buf_switch is called from the foreground when getting a journal
reservation and thus is somewhat latency sensitive;
bch2_bucket_seq_cleanup has to run infrequently but is a bit expensive
when it does run.

Call it from the journal write path instead, and punt the journal write
to worqueue context.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

bcachefs: Initial commit

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>