The btree_trans struct needs to memoize/cache btree iterators, so that
on transaction restart we don't have to completely redo btree lookups,
and so that we can do them all at once in the correct order when the
transaction had to restart to avoid a deadlock.

This switches the btree iterator lookups to work based on iterator
position, instead of trying to match them up based on the stack trace.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

Will be replaced by cached btree iterators
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>

Change it to match for_each_btree_key()
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>

We shouldn't ever be writing past i_size - but, apparently there's still
a bug to track down.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

In order to avoid trying to allocate too many btree iterators,
bch2_extent_atomic_end() needs to count how many iterators are going to
be needed for insertions and overwrites - but we weren't counting the
iterators for deleting a reflink_v when the refcount goes to 0.
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>

If the user buffer isn't aligned to the filesystem block size, on a
large enough IO - where it won't fit into a single bio -
bio_iov_iter_get_pages() won't necessarily return a bio with the proper
alignment.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

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

When an extent is erasure coded, we need to record a replicas entry to
indicate that data is present on the devices that extent has pointers to
- but nr_required should be 0, because it's erasure coded.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

Somewhat tricky and ugly, because iterating over extents backwards is a
pain.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

Last of the basic operations for iterating forwards and backwards over
the btree: we now have
 - peek(),	returns key >= iter->pos
 - next(),	returns key >  iter->pos
 - peek_prev(),	returns key <= iter->pos
 - prev(),	returns key < iter->pos
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

When converting from PAGE_SIZE to block_size, the .mkwrite path was
missed
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

bcachefs used to work mostly in terms of PAGE_SIZE, not block size at
the vfs level - but that has since been fixed.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

Call bch2_btree_iter_verify from bch2_btree_node_iter_fix(); also verify
in btree_iter_peek_uptodate() that iter->k matches what's in the btree.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

Any time we're modifying what's in the btree, iterators potentially have
to be updated - this one was exposed by the reflink code.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

The allocator needs to make sure there's buckets available on the
RESERVE_NONE freelist if at all possible - otherwise foreground IO will
get stuck.
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>

.key_debugcheck no longer needs to take a pointer to the btree node

Also, try to make sure wherever we're inserting or modifying keys in the
btree.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

With multiple iterators, if another iterator points to the key being
modified, we need to call bch2_btree_node_iter_fix() to re-unpack the
key into the iter->k
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

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

_iter, not iter
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

Move extents instead of copying them - this way, we can iterate over
only live extents, not the entire keyspace. Also, this means we can
mostly skip running triggers.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

Being more rigorous about noting when the key the iterator currently
poins to has changed - which should also give us a nice performance
improvement due to not having to check if we have to skip other bsets
backwards as much.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

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

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

This was spotted when the move_extent() path tried to allocate a bio for
a reflink_p extent, but adding pages to the bio failed because we
overflowed bi_max_vecs. Oops.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

rbio->c wasn't being initialized in the move 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>

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

bch2_mark_update() was correct, but bch2_trans_mark_update() wasn't
respecting BTREE_INSERT_NOMARK_OVERWRITES - key marking/triggers really
need to be cleaned up.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

Importantly, we don't want to use bch2_fs_inconsistent_on() for errors
that fsck can repair, becuase that will just put us in RO mode and
prevent fsck from actually fixing stuff. Probably want to get rid of it
in the future.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

Right now this is the only way of repairing bucket gens in the future
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

when iterating over reflink pointers, we use the key we just emitted to
set the iterator position - which means we have to be setting the key's
inode field as well
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>