Add a new refcount for async ops that don't necessarily need the fs to
be RW, with similar lifetime/rules otherwise as c->writes.

To be used by online fsck.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

single_device.merge_torture_flakey is, very rarely, finding a btree node
that doesn't match the key that points to it: this patch improves the
error message to print out more fields from the btree node header, so
that we can see what else does or does not match the key.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

When investigating transient failures of generic/441 on bcachefs, it
was determined that the cause of the failure was a combination of
unconditional emergency shutdown and racing between background
journal activity and the test switchover from a working device
mapper table to an error injecting table.

Part of the reason for this sequence of events is that bcachefs
aggressively flushes as much as possible during fsync(), regardless
of errors. While this is reasonable behavior, it is technically
unnecessary because once an error is returned from fsync(), the
caller cannot make any assumptions about the resilience of data.

Tweak the bch2_fsync() logic to return an error on failure of any of
the steps involved in the flush. Note that this change alone does
not prevent generic/441 failure, but in combination with a test
tweak to avoid racing during the dm-error table switchover it avoids
the unnecessary shutdowns and allows the test to pass reliably on
bcachefs.
Signed-off-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

Continuing the project of replacing generic error codes with more
specific ones.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

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

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

Remove obsolete comment about zstd, since approach changed during
development of commit bbc3a460Signed-off-by: Richard Davies <richard@arachsys.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

This gives us more context information - e.g. which codepath is invoking
btree node reads.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

bcachefs grabs s_umount and sets SB_RDONLY when the fs is shutdown
via the ioctl() interface. This has a couple issues related to
interactions between shutdown and freeze:

1. The flags == FSOP_GOING_FLAGS_DEFAULT case is a deadlock vector
   because freeze_bdev() calls into freeze_super(), which also
   acquires s_umount.

2. If an explicit shutdown occurs while the sb is frozen, SB_RDONLY
   alters the thaw path as if the sb was read-only at freeze time.
   This effectively leaks the frozen state and leaves the sb frozen
   indefinitely.

The usage of SB_RDONLY here goes back to the initial bcachefs commit
and AFAICT is simply historical behavior. This behavior is unique to
bcachefs relative to the handful of other filesystems that support
the shutdown ioctl(). Typically, SB_RDONLY is reserved for the
proper remount path, which itself is restricted from modifying
frozen superblocks in reconfigure_super(). Drop the unnecessary sb
lock and flags update bch2_ioc_goingdown() to address both of these
issues.
Signed-off-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

backpointers fsck now always runs in rw mode - the btree is being
modified while it runs, by e.g. copygc, rebalance, the discard worker,
the invalidate worker.

We could find a missing backpointer, flush the btree write buffer, and
then on the next iteration find a new key at the exact same position -
which will most likely need another write buffer flush.

Hence, we have to check for an exact match on last_flushed, not just the
pos.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

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

Signed-off-by: Daniel Hill <daniel@gluo.nz>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

Co-developed-by: Kent Overstreet <kent.overstreet@linux.dev>
Signed-off-by: Daniel Hill <daniel@gluo.nz>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

This eliminates a lot of BCH_TRANS_COMMIT_lazy_rw flags, and is less
error prone.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

Signed-off-by: Daniel Hill <daniel@gluo.nz>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

Signed-off-by: Daniel Hill <daniel@gluo.nz>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

Signed-off-by: Daniel Hill <daniel@gluo.nz>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

Fake flexible arrays (zero-length and one-element arrays) are
deprecated, and should be replaced by flexible-array members.

So, replace zero-length arrays with flexible-array members
in multiple structures.
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

prep work for big rewrite - no functional changes in this patch.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

A bit of refactoring for better inlining in the main btree write buffer
flush path.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

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

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

In the CI, we're seeing tests failing due to excessive would_deadlock
transaction restarts - the tracepoint now includes the lock cycle that
occured.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

We now include the list of paths in use.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

Small helper for event counters.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

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

Minor refactoring - improved naming, and move the responsibility for
flush_lock to the caller instead of having it be shared.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

__bch2_btree_write_buffer_flush() now assumes a write ref is already
held (as called by the transaction commit path); and the wrappers
bch2_write_buffer_flush() and flush_sync() take an explicit write ref.

This means internally the write buffer code can always use
BTREE_INSERT_NOCHECK_RW, instead of in the previous code passing flags
around and hoping the NOCHECK_RW flag was always carried around
correctly.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

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

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

 - add a tracepoint for write_buffer_flush_sync; this is expensive
 - fix the write_buffer_flush_slowpath tracepoint
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

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

Now we can print out filesystem flags in sysfs, useful for debugging
various "what's my filesystem doing" issues.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

This is only used by gc (fsck).
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

This code was somewhat convoluted - because originally bch2_lru_set()
could modify the LRU index if there was a collision.

That's no longer the case, so the "create LRU entry" path has no reason
to update the alloc key, so we can separate the handling of the two fsck
errors.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

Add a tracepoint for rebalance, printing out
 - the target option
 - the compression option
 - the key being rebalanced
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

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

Break it out by compression type, and include average extent size.

Also, format into a nice table.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

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>

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