The new convention is that functions that handle transaction restarts
within an existing transaction context should return
-BCH_ERR_transaction_restart_nested when they did so, since they
invalidated the outer transaction context.

This also means bch2_btree_delete_range_trans() is changed to only call
bch2_trans_begin() after a transaction restart, not on every loop
iteration.

This is to fix a bug in fsck, in check_inode() when we truncate an inode
with BCH_INODE_I_SIZE_DIRTY set.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

 - fsck_inode_rm() wasn't returning BCH_ERR_transaction_restart_nested
 - change bch2_trans_verify_not_restarted() to call panic() - we don't
   want these errors to be missed
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

iter->k needs to be consistent with iter->pos - required for
bch2_btree_iter_(rewind|advance) to work correctly.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

When returning a key from the key cache, in BTREE_ITER_WITH_KEY_CACHE
mode, we don't want to set should_be_locked on iter->path; we're not
returning a key from that path, so we donn't need to, and also since we
traversed the key cache iterator before setting should_be_locked on that
path it might be unlocked (if we unlocked, bch2_trans_relock() won't
have relocked it).
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

For debugging the eytzinger search tree code, and low level bkey packing
code, it can be helpful to see things in binary: this patch improves our
helpers for doing so.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

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

We should be calling btree_node_mem_ptr_set() before path_level_init(),
since we already touched the key that btree_node_mem_ptr_set() will
modify and path_level_init() will be doing the lookup in the child btree
node we're recursing to.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

Topology repair may change btree node min/max keys: when it does so, we
need to always rebuild eytzinger search trees because nodes directly
depend on those values.

This fixes a bug found by the 'kill_btree_node' test, where we'd pop an
assertion in bch2_bset_search_linear().
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

For now this is just a BUG_ON() - we may want to change this to return
an error in the future.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

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

This improves flush_buf() so that it always returns nonzero when we're
done reading and ready to return to userspace, and so that it returns
the value we want to return to userspace (number of bytes read, if there
wasn't an error).

In the future we'll be better abstracting this mechanism and pulling it
out of bcachefs, and using it to replace seq_file.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

We were iterating starting at BCACHEFS_ROOT_INO, but snapshots start at
POS_MIN - meaning this code was never getting run.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Reported-by: Olexa Bilaniuk <obilaniu@gmail.com>

Instead of counting transaction restarts, count when the transaction is
restarted: if bch2_trans_begin() was called when the transaction wasn't
restarted we need to ensure restart_count is still incremented.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

Turns out this assertion was something we could legitimately hit - add a
comment describing what's going on, and handle it.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

We need to turn the flush_buf() thing into a proper API, to replace
seq_file.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

We need a way to check if the machinery for handling btree_paths with in
a transaction is behaving reasonably, as it often has not been - we've
had bugs with transaction path overflows caused by duplicate paths and
plenty of other things.

This patch tracks, per transaction fn, the most btree paths ever
allocated by that transaction and makes it available in debugfs.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

Going to be adding more things to this in the next patch.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

This fixes an assertion about unexpected transaction restarts -
bch2_delete_range_trans() handles transaction restarts.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

This fixes an assertion in bch2_btree_path_peek_slot().
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

bch2_path_put() is supposed to drop paths that aren't needed on
transaction restart, or to hold locks that we're supposed to keep until
transaction commit: but it was failing to free paths in some cases that
it should have, leading to transaction path overflows with lots of
duplicate paths.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

These were used more prior to getting rid of the in-memory bucket arrays
- they don't serve much purpose anymore, and deleting them lets us write
better assertions.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

Our types are exported to the tracepoint code, so it's not necessary to
break things out individually when passing them to tracepoints - we can
also call other functions from TP_fast_assign().
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

This was noticed when a test hit this error and didn't fail, because
fsck wasn't returning that it fixed errors.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

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

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

It doesn't make any sense to set should_be_locked on btree_paths that
aren't locked, and is often a bug - this patch adds assertions and fixes
some of those bugs.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

This fixes an assertion when the transaction has been unexpectedly
restarted.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

Update an error message to use bch2_err_str().
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

 - use strlcpy(), not strncpy()
 - add tracepoints for btree_path alloc and free
 - give the tracepoint for key cache upgrade fail a proper name
 - add a tracepoint for btree_node_upgrade_fail
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

Clearing path->preserve means the path will be dropping in
bch2_trans_begin() - but on transaction restart, we're likely to need
that path again.

This fixes a livelock in the allocation path.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

bch2_btree_trans_to_text() is used to print btree_transactions owned by
other threads; thus, it needs to be particularly careful. This fixes a
null ptr deref caused by racing with the owning thread changing
path->l[].b.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

This aids in debugging.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

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

This uses the new trans->restart count to make sure we always correctly
return -BCH_ERR_transaction_restart_nested when we restart a nested
transaction - eliminating some other hacks and preparing for new
assertions.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

Sometimes we see IO errors due to O_DIRECT alignment issues - having an
option to use buffered IO will be helpful.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

Currently seeing a very rare and difficult to explain btree_path
inconsistency - this patch adds assertions to the only place that seems
to be missing them.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

Nested btree transactions require special care, and an upcoming patch is
going to add assertions to that effect. We don't want to be using them
unnecessarily, so this patch switches bch2_bucket_trans_early() to not
handle transaction restarts.

This patch also adds a cursor so that on transaction restart we can
continue scanning from where the previous search for an empty bucket
left off.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

bch2_count_inode_sectors() uses for_each_btree_key() internally, which
handles lock restarts - the lockrestart_do() in check_i_sectors() is
redundant, and buggy here since the count that
bch2_count_inode_sectors() returns was interpreted as an error by
lockrestart_do().
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

This fixes a bug where we were leaking a transaction restart error to
userspace.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

 - Convert to for_each_btree_key2(), for_each_btree_key_commit(),
   for_each_btree_key_reverse()
 - No more bare bch2_btree_iter_peek(); we're now fault-injection lock
   restarts, so we always need a lockrestart_do() or equivalent.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>