bcachefs: Check for backpointer bucket_offset >= bucket size

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

bcachefs: Kill bch2_bkey_ptr_data_type()

Remove some duplication, and inconsistency between check_fix_ptrs and
the main ptr marking paths

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

bcachefs: Prep work for variable size btree node buffers

bcachefs btree nodes are big - typically 256k - and btree roots are
pinned in memory. As we're now up to 18 btrees, we now have significant
memory overhead in mostly empty btree roots.

And in the future we're going to start enforcing that certain btree node
boundaries exist, to solve lock contention issues - analagous to XFS's
AGIs.

Thus, we need to start allocating smaller btree node buffers when we
can. This patch changes code that refers to the filesystem constant
c->opts.btree_node_size to refer to the btree node buffer size -
btree_buf_bytes() - where appropriate.

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

bcachefs: No need to allocate keys for write buffer

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

bcachefs: use swab40 for bch_backpointer.bucket_offset bitfield

The bucket_offset field of bch_backpointer is a 40-bit bitfield, but the
bch2_backpointer_swab() helper uses swab32. This leads to inconsistency
when an on-disk fs is accessed from an opposite endian machine.

As it turns out, we already have an internal swab40() helper that is
used from the bch_alloc_v4 swab callback. Lift it into the backpointers
header file and use it consistently in both places.

Signed-off-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

bcachefs: Enumerate fsck errors

This patch adds a superblock error counter for every distinct fsck
error; this means that when analyzing filesystems out in the wild we'll
be able to see what sorts of inconsistencies are being found and repair,
and hence what bugs to look for.

Errors validating bkeys are not yet considered distinct fsck errors, but
this patch adds a new helper, bkey_fsck_err(), in order to add distinct
error types for them as well.

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

bcachefs: remove duplicate code between backpointer update paths

Signed-off-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

bcachefs: Change check for invalid key types

As part of the forward compatibility patch series, we need to allow for
new key types without complaining loudly when running an old version.

This patch changes the flags parameter of bkey_invalid to an enum, and
adds a new flag to indicate we're being called from the transaction
commit path.

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

bcachefs: bkey_ops.min_val_size

This adds a new field to bkey_ops for the minimum size of the value,
which standardizes that check and also enforces the new rule (previously
done somewhat ad-hoc) that we can extend value types by adding new
fields on to the end.

To make that work we do _not_ initialize min_val_size with sizeof,
instead we initialize it to the size of the first version of those
values.

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

bcachefs: Rip out code for storing backpointers in alloc keys

We don't store backpointers in alloc keys anymore, since we gained the
btree write buffer.

This patch drops support for backpointers in alloc keys, and revs the on
disk format version so that we know a fsck is required.

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

bcachefs: Use BTREE_ITER_INTENT in ec_stripe_update_extent()

This adds a flags param to bch2_backpointer_get_key() so that we can
pass BTREE_ITER_INTENT, since ec_stripe_update_extent() is updating the
extent immediately.

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

bcachefs: Improve the backpointer to missing extent message

We now print the pos where the backpointer was found in the btree, as
well as the exact bucket:bucket_offset of the data, to aid in grepping
through logs.

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

bcachefs: Mark stripe buckets with correct data type

Currently, we don't use bucket data type for tracking whether buckets
are part of a stripe; parity buckets are BCH_DATA_parity, but data
buckets in a stripe are BCH_DATA_user. There's a separate counter,
buckets_ec, outside the BCH_DATA_TYPES system for tracking number of
buckets on a device that are part of a stripe.

The trouble with this approach is that it's too coarse grained, and we
need better information on fragmentation for debugging copygc.

With this patch, data buckets in a stripe are now tracked as
BCH_DATA_stripe buckets.

This doesn't yet differentiate between erasure coded and non-erasure
coded data in a stripe bucket, nor do we yet track empty data buckets in
stripes.

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

bcachefs: Change bkey_invalid() rw param to flags

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

bcachefs: Don't use key cache during fsck

The btree key cache mainly helps with lock contention, at the cost of
additional memory overhead. During some fsck passes the memory overhead
really matters, but fsck is single threaded so lock contention is an
issue - so skipping the key cache during fsck will help with
performance.

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

bcachefs: New on disk format: Backpointers

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>