Delete some obsolete tracepoints, organize alloc tracepoints better,
make a few tracepoints more consistent.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
For backpointers, we'll need the full key location - that means btree_id
and btree level. This patch plumbs it through.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
When we detect a filesystem inconsistency, we should include the
relevent keys in the error message. This patch adds a parameter to pass
the key with the lru entry to bch2_lru_delete(), so that it can be
printed.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Error messages should always print out the full key when available -
this gives us a starting point when looking through the journal to debug
what went wrong.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
It's an error if a bucket is in state BCH_DATA_cached but not on the LRU
btree - i.e io_time[READ] == 0 - so, make sure it's set before adding
it.
Also, make some of the LRU code a bit clearer and more direct.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
- We weren't clearing the LRU btree
- bch2_alloc_read() runs before bch2_check_alloc_key() deletes alloc
keys for devices/buckets that don't exists, so it needs to check for
that
- bch2_check_lrus() needs to check that buckets exists
- improve some error messages
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
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>
We've been seeing this error in fsck and we weren't able to track down
where it came from - but now that .key_invalid methods take a rw
argument, we can safely check for this.
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>
- Move checks for whether the device & bucket are valid from the
.key_invalid method to bch2_check_alloc_key(). This is because
.key_invalid() is called on keys that may no longer exist (post
journal replay), which is a problem when removing/resizing devices.
- We weren't checking the need_discard btree to ensure that every set
bucket has a corresponding alloc key. This refactors the code for
checking the freespace btree, so that it now checks both.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
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>
In the old allocator code, preparing an existing empty bucket was part
of the same code path that invalidated buckets containing cached data.
In the new allocator code this is no longer the case: the main allocator
path finds empty buckets (via the new freespace btree), and can't
allocate buckets that contain cached data.
We now need a separate code path to invalidate buckets containing cached
data when we're low on empty buckets, which this patch implements. When
the number of free buckets decreases that triggers the new invalidate
path to run, which uses the LRU btree to pick cached data buckets to
invalidate until we're above our watermark.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
In the old allocator code, buckets would be discarded just prior to
being used - this made sense in bcache where we were discarding buckets
just after invalidating the cached data they contain, but in a
filesystem where we typically have more free space we want to be
discarding buckets when they become empty.
This patch implements the new behaviour - it checks the need_discard
btree for buckets awaiting discards, and then clears the appropriate
bit in the alloc btree, which moves the buckets to the freespace btree.
Additionally, discards are now enabled by default.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
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>
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>
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>
Since journal reclaim -> btree key cache flushing may require the
allocation of new btree nodes, it has an implicit dependency on copygc
in order to make forward progress - so we should avoid blocking copygc
unless the journal is really close to full.
This introduces watermarks to replace our single MAY_GET_UNRESERVED bit
in the journal, and adds a watermark for copygc and plumbs it through.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
When the nochanges option is selected, we're supposed to never issue
writes. Unfortunately, it seems discards were missed when implemnting
this, leading to some painful filesystem corruption.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
This changes the btree_gc code to only use the second bucket array, the
one dedicated to GC. On completion, it compares what's in its in memory
bucket array to the allocation information in the btree and writes it
directly, instead of updating the main in-memory bucket array and
writing that.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
- Updates to non key cache iterators will now be transparently
redirected to the key cache for cached btrees.
- Except when creating new keys: then the update goes to underlying
btree
For for iterating over a cached btree to work, we need to ensure that if
a key exists in the key cache, it also exists in the btree - otherwise
the iterator code will skip past it and not check the key cache.
Otherwise, for consistency, all updates should go to the same place -
the key cache.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Previously, bucket fragmentation was considered to be bucket size -
total amount of live data, both dirty and cached.
This meant that if a bucket was full but only a small amount of data in
it was dirty - the rest cached, we'd get stuck: copygc wouldn't move the
dirty data out of the bucket and the allocator wouldn't be able to
invalidate and drop the cached data.
This changes fragmentation to exclude cached data, so that copygc will
evacuate these buckets and copygc/the allocator will always be able to
make forward progress.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
More prep work for getting rid of the in-memory bucket array: now that
we have BTREE_ITER_WITH_JOURNAL, the allocator code can do ntree lookups
before journal replay is finished, and there's no longer any need for it
to get allocation information from the in-memory bucket array.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
The allocator thread invalidates buckets (increments their generation
number) prior to discarding them and putting them on freelists. We've
had a short circuit path for some time to only update the in-memory
bucket mark when doing the invalidate if we're not invalidating cached
data, but that short-circuit path hasn't really been needed for quite
some time (likely since the btree key cache code was added).
We're deleting it now as part of deleting/converting code that uses the
in memory bucket array.
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>
With BTREE_ITER_WITH_JOURNAL, there's no longer any restrictions on the
order we have to replay keys from the journal in, and we can also start
up journal reclaim right away - and delete a bunch of code.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
This adds a new btree iterator flag, BTREE_ITER_WITH_JOURNAL, that is
automatically enabled when initializing a btree iterator before journal
replay has completed - it overlays the contents of the journal with the
btree.
This lets us delete bch2_btree_and_journal_walk() and just use the
normal btree iterator interface instead - which also lets us delete a
significant amount of duplicated code.
Note that BTREE_ITER_WITH_JOURNAL is still unoptimized in this patch -
we're redoing the binary search over keys in the journal every time we
call bch2_btree_iter_peek().
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
The allocator needs to wait until the last update touching a bucket has
been commited before writing to it again. However, the code was checking
against the last dirty journal sequence number, not the last flushed
journal sequence number.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
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>
Prep work for adding a hash table of open buckets - instead of embedding
a bch_extent_ptr, we need to refer to the bucket directly so that we're
not calling sector_to_bucket() in the hash table lookup code, which has
an expensive divide.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
If the allocator threads start before journal replay has finished
replaying alloc keys, journal replay might overwrite the allocator's
btree updates.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
This changes bch2_bucket_alloc_new_fs() to a simple bump allocator that
doesn't need to use the in memory bucket array, part of a larger patch
series to entirely get rid of the in memory bucket array, except for
gc/fsck.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
This moves some common code into alloc_mem_to_key(), which translates
from the in-memory format for a bucket to the btree key format.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
This adds a new helper that much like the one we have for inode updates,
that allocates the packed alloc key, packs it and calls
bch2_trans_update.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
When we added the stripe and stripe_redundancy fields to alloc keys, we
neglected to add them to the functions that convert back and forth with
the in-memory types.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Add fields to inode & alloc keys that record the journal sequence number
when they were most recently modified.
For alloc keys, this is needed to know what journal sequence number we
have to flush before the bucket can be reused. Currently this is tracked
in memory, but we'll be getting rid of the in memory bucket array.
For inodes, this is needed for fsync when the inode has been evicted
from the vfs cache. Currently we use a bloom filter per outstanding
journal buf - but that mechanism has been broken since we added the
ability to not issue a flush/fua for every journal write.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
This helps to unify the interface between bch2_mark_key() and
bch2_trans_mark_key() - and it also gives access to the journal
reservation and journal seq in the mark_key path.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
But we don't need to call it from outside the btree iterator code
anymore, since it's called by bch2_trans_begin() and
bch2_btree_path_traverse().
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
We return 1 to indicate kthread_should_stop() returned true - we
shouldn't be printing an error.
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>
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>
This adds safe versions of bch2_varint_(encode|decode) that don't read
or write past the end of the buffer, or varint being encoded.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
This is to help debug a rare shutdown deadlock in the allocator code -
the btree code is leaking open_buckets.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Upcoming refactoring is going to change bch2_trans_update() to start
returning transaction restarts.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
