JOURNAL_RES_GET_RESERVED should only be used for updatse that need to be
done to free up space in the journal. In particular, when we're flushing
keys from the key cache, if we're flushing them out of order we
shouldn't be using it, since we're using up our remaining space in the
journal without dropping a pin that will let us make forward progress.
With this patch, BTREE_INSERT_JOURNAL_RECLAIM without
BTREE_INSERT_JOURNAL_RESERVED may return -EAGAIN - we can't wait on
journal reclaim if we're already in journal reclaim.
This means we need to propagate these errors up to journal reclaim,
indicating that flushing a journal pin should be retried in the future.
This is prep work for a patch to change the way journal reclaim works,
to split out flushing key cache keys because the btree key cache is too
dirty from journal reclaim because we need space in the journal.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
All writes prior to a journal write need to be flushed before the
journal write itself happens. On single device filesystems, it suffices
to mark the write with REQ_PREFLUSH|REQ_FUA, but on multi device
filesystems we need to issue flushes to every device - and wait for them
to complete - before issuing the journal writes. Previously, we were
issuing flushes to every device, but we weren't waiting for them to
complete before issuing the journal writes.
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>
- Try to always keep 1/8th of the journal free, on top of
pre-reservations
- Move the check for whether the journal is stuck to
bch2_journal_space_available, and make it only fire when there aren't
any journal writes in flight (that might free up space by updating
last_seq)
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
This patch adds a flag to journal entries which, if set, indicates that
they weren't done as flush/fua writes.
- non flush/fua journal writes don't update last_seq (i.e. they don't
free up space in the journal), thus the journal free space
calculations now check whether nonflush journal writes are currently
allowed (i.e. are we low on free space, or would doing a flush write
free up a lot of space in the journal)
- write_delay_ms, the user configurable option for when open journal
entries are automatically written, is now interpreted as the max
delay between flush journal writes (default 1 second).
- bch2_journal_flush_seq_async is changed to ensure a flush write >=
the requested sequence number has happened
- journal read/replay must now ignore, and blacklist, any journal
entries newer than the most recent flush entry in the journal. Also,
the way the read_entire_journal option is handled has been improved;
struct journal_replay now has an entry, 'ignore', for entries that
were read but should not be used.
- assorted refactoring and improvements related to journal read in
journal_io.c and recovery.c
Previously, we'd have to issue a flush/fua write every time we
accumulated a full journal entry - typically the bucket size. Now we
need to issue them much less frequently: when an fsync is requested, or
it's been more than write_delay_ms since the last flush, or when we need
to free up space in the journal. This is a significant performance
improvement on many write heavy workloads.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
This patch increases the maximum journal buffers in flight from 2 to 4 -
this will be particularly helpful when in the future we stop requiring
flush+fua for every journal write.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Various filesystem usage counters are kept in percpu counters, with one
set per in flight journal buffer. Right now all the code that deals with
it assumes that there's only two buffers/sets of counters, but the
number of journal bufs is getting increased to 4 in the next patch - so
refactor that code to not assume a constant.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
We were incorrectly detecting a journal deadlock - the journal filling
up - when only the journal pin fifo had filled up; if the journal pin
fifo is full that just means we need to wait on reclaim.
This plumbs through better error reporting so we can better discriminate
in the journal_res_get path what's going on.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Improved the way we track various state by adding j->err_seq, which
records the first journal sequence number that encountered an error
being written, and j->last_empty_seq, which records the most recent
journal entry that was completely empty.
Also, use the low bits of the journal sequence number to index the
corresponding journal_buf.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Now, we store blacklisted journal sequence numbers in the superblock,
not the journal: this helps to greatly simplify the code, and more
importantly it's now implemented in a way that doesn't require all btree
nodes to be visited before starting the journal - instead, we
unconditionally blacklist the next 4 journal sequence numbers after an
unclean shutdown.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Also improve error reporting - only return an error from
bch2_journal_flush_seq() if we had an error writing that entry (i.e. not
if there was an error with a newer entry).
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>
Kent Overstreet