All the fastpaths that need device usage don't need the sector totals or
fragmentation, just bucket counts.

Split bch_dev_usage up into two different versions, the normal one with
just bucket counts.

This is also a stack usage improvement, since we have a bch_dev_usage on
the stack in the allocation path.

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

Necessary for adding backpointers for cached pointers.

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

When calling check_discard_freeespace_key from the allocator, we can't
repair without recursing - run it asynchronously instead.

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

Add a new parameter to bkey validate functions, and use it to improve
invalid bkey error messages: we can now print the btree and depth it
came from, or if it came from the journal, or is a btree root.

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

check_discard_freespace_key() was doing all the same checks as
try_alloc_bucket(), but with repair.

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

The size of a.data_type is set abnormally large, causing shift-out-of-bounds.
To fix this, we need to add validation on a.data_type in
alloc_lru_idx_fragmentation().

Reported-by: syzbot+7f45fa9805c40db3f108@syzkaller.appspotmail.com
Fixes: 260af1562ec1 ("bcachefs: Kill alloc_v4.fragmentation_lru")
Signed-off-by: Jeongjun Park <aha310510@gmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

bch2_dev_rcu() now properly errors if the device is invalid

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

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

Reported-by: syzbot+510b0b28f8e6de64d307@syzkaller.appspotmail.com
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

bkey_fsck_err() was added as an interface that looks like fsck_err(),
but previously all it did was ensure that the appropriate error counter
was incremented in the superblock.

This is a cleanup and bugfix patch that converts it to a wrapper around
fsck_err(). This is needed to fix an issue with the upgrade path to
disk_accounting_v3, where the "silent fix" error list now includes
bkey_fsck errors; fsck_err() handles this in a unified way, and since we
need to change printing of bkey fsck errors from the caller to the inner
bkey_fsck_err() calls, this ends up being a pretty big change.

Als,, rename .invalid() methods to .validate(), for clarity, while we're
changing the function signature anyways (to drop the printbuf argument).

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