bcachefs: Improved topology repair checks

Consolidate bch2_gc_check_topology() and btree_node_interior_verify(),
and replace them with an improved version,
bch2_btree_node_check_topology().

This checks that children of an interior node correctly span the full
range of the parent node with no overlaps.

Also, ensure that topology repairs at runtime are always a fatal error;
in particular, this adds a check in btree_iter_down() - if we don't find
a key while walking down the btree that's indicative of a topology error
and should be flagged as such, not a null ptr deref.

Some checks in btree_update_interior.c remaining BUG_ONS(), because we
already checked the node for topology errors when starting the update,
and the assertions indicate that we _just_ corrupted the btree node -
i.e. the problem can't be that existing on disk corruption, they
indicate an actual algorithmic bug.

In the future, we'll be annotating the fsck errors list with which
recovery pass corrects them; the open coded "run explicit recovery pass
or fatal error" in bch2_btree_node_check_topology() will in the future
be done for every fsck_err() call.

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

bcachefs: Improve bch2_fatal_error()

error messages should always include __func__

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

bcachefs: Kill more -EIO error codes

This converts -EIOs related to btree node errors to private error codes,
which will help with some ongoing debugging by giving us better error
messages.

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

bcachefs: fix BCH_FSCK_ERR enum

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: Add IO error counts to bch_member

We now track IO errors per device since filesystem creation.

IO error counts can be viewed in sysfs, or with the 'bcachefs
show-super' command.

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

bcachefs: fix_errors option is now a proper enum

Before, it was parsed as a bool but internally it was really an enum:
this lets us pass in all the possible values.

But we special case the option parsing: no supplied value is parsed as
FSCK_FIX_yes, to match the previous behaviour.

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

bcachefs: Allow answering y or n to all fsck errors of given type

This changes the ask_yn() function used by fsck to accept Y or N,
meaning yes or no for all errors of a given type.

With this, the user can be prompted only for distinct error types -
useful when a filesystem has lots of errors.

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

bcachefs: Don't print out duplicate fsck errors

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

bcachefs: Dump transaction updates before panicing

When errors=panic, we need to dump transaction updates before calling
bch2_inconsistent_error().

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

bcachefs: Error message improvement

- Centralize format strings in bcachefs.h
- Add bch2_fmt_inum_offset() and related helpers
- Switch error messages for inodes to also print out the offset, in
bytes

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

bcachefs: Improve bch2_fsck_err()

- factor out fsck_err_get()
- if the "bcachefs (%s):" prefix has already been applied, don't
duplicate it
- convert to printbufs instead of static char arrays
- tidy up control flow a bit
- use bch2_print_string_as_lines(), to avoid messages getting truncated

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

bcachefs: Convert fsck errors to errcode.h

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

bcachefs: bch2_trans_inconsistent()

Add a new error macro that also dumps transaction updates in addition to
doing an emergency shutdown - when a transaction update discovers or is
causing a fs inconsistency, it's helpful to see what updates it was
doing.

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

bcachefs: Use unlikely() in err_on() macros

Should be obviously a good thing.

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

bcachefs: Don't ratelimit certain fsck errors

It's unhelpful if we see "Halting mark and sweep to start topology
repair" but we don't see the error that triggered it.

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

bcachefs: New and improved topology repair code

This splits out btree topology repair into a separate pass, and makes
some improvements:
- When we have to pick which of two overlapping nodes to drop keys
from, we use the btree node header sequence number to preserve the
newer node

- the gc code has been changed so that it doesn't bail out if we're
continuing/ignoring on fsck error - this way the dump tool can skip
running the repair pass but still walk all reachable metadata

- add a new superblock flag indicating when a filesystem is known to
have btree topology issues, and the topology repair pass should be
run

- changing the start/end of a node might mean keys in that node have to
be deleted: this patch handles that better by splitting it out into a
separate function and running it explicitly in the topology repair
code, previously those keys were only being dropped when the btree
node was read in.

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

bcachefs: Improve some IO error messages

it's useful to know whether an error was for a read or a write - this
also standardizes error messages a bit more.

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

bcachefs: Improve assorted error messages

This also consolidates the various checks in bch2_mark_pointer() and
bch2_trans_mark_pointer().

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

bcachefs: Kill bch2_fs_bug()

These have all been converted to fsck/inconsistent errors

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

bcachefs: Add an option for fsck error ratelimiting

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