247 Commits

Author SHA1 Message Date
Kent Overstreet
01e691e830 bcachefs: Fix a write buffer flush deadlock
We're not supposed to block if BTREE_INSERT_JOURNAL_RECLAIM && watermark
!= BCH_WATERMARK_reclaim.

This should really be a separate BTREE_INSERT_NONBLOCK flag - add some
comments to that effect, it's not important for this patch.

btree write buffer flush depends on this behaviour though - the first
loop tries to flush sequentially, which doesn't free up space in the
journal optimally. If that can't proceed we bail out and flush in
journal order - that won't work if we're blocked instead of returning an
error.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2023-10-22 17:10:06 -04:00
Kent Overstreet
73bd774d28 bcachefs: Assorted sparse fixes
- endianness fixes
 - mark some things static
 - fix a few __percpu annotations
 - fix silent enum conversions

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2023-10-22 17:10:06 -04:00
Kent Overstreet
faa6cb6c13 bcachefs: Allow for unknown btree IDs
We need to allow filesystems with metadata from newer versions to be
mountable and usable by older versions.

This patch enables us to roll out new btrees without a new major version
number; we can now handle btree roots for unknown btree types.

The unknown btree roots will be retained, and fsck (including
backpointers) will check them, the same as other btree types.

We add a dynamic array for the extra, unknown btree roots, in addition
to the fixed size btree root array, and add new helpers for looking up
btree roots.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2023-10-22 17:10:05 -04:00
Kent Overstreet
f33c58fc46 bcachefs: Kill BTREE_INSERT_USE_RESERVE
Now that we have journal watermarks and alloc watermarks unified,
BTREE_INSERT_USE_RESERVE is redundant and can be deleted.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2023-10-22 17:10:05 -04:00
Kent Overstreet
65db60490a bcachefs: Fix a null ptr deref in bch2_fs_alloc() error path
This fixes a null ptr deref in bch2_free_pending_node_rewrites() when
the list head wasn't initialized.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2023-10-22 17:10:05 -04:00
Kent Overstreet
ec14fc6010 bcachefs: Kill JOURNAL_WATERMARK
This unifies JOURNAL_WATERMARK with BCH_WATERMARK; we're working towards
specifying watermarks once in the transaction commit path.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2023-10-22 17:10:05 -04:00
Kent Overstreet
e53a961c6b bcachefs: Rename enum alloc_reserve -> bch_watermark
This is prep work for consolidating with JOURNAL_WATERMARK.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2023-10-22 17:10:04 -04:00
Kent Overstreet
45a1ab57dd bcachefs: Fix bch2_btree_update_start()
The calculation for number of nodes to allocate in
bch2_btree_update_start() was incorrect - this fixes a BUG_ON() on the
small nodes test.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2023-10-22 17:10:04 -04:00
Kent Overstreet
25c70097a6 bcachefs: Delete weird hacky transaction restart injection
since we currently don't have a good fault injection library,
bch2_btree_insert_node() was randomly injecting faults based on
local_clock().

At the very least this should have been a debug mode only thing, but
this is a brittle method so let's just delete it.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2023-10-22 17:10:04 -04:00
Kent Overstreet
49c7cd9d8d bcachefs: More drop_locks_do() conversions
Using drop_locks_do() ensures that every unlock() is paired with a
relock(), with proper error checking.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2023-10-22 17:10:03 -04:00
Kent Overstreet
b5fd75669a bcachefs: drop_locks_do()
Add a new helper for the common pattern of:
 - trans_unlock()
 - do something
 - trans_relock()

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2023-10-22 17:10:03 -04:00
Kent Overstreet
19c304bebd bcachefs: GFP_NOIO -> GFP_NOFS
GFP_NOIO dates from the bcache days, when we operated under the block
layer. Now, GFP_NOFS is more appropriate, so switch all GFP_NOIO uses to
GFP_NOFS.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2023-10-22 17:10:03 -04:00
Kent Overstreet
1fb4fe6317 six locks: Kill six_lock_state union
As suggested by Linus, this drops the six_lock_state union in favor of
raw bitmasks.

On the one hand, bitfields give more type-level structure to the code.
However, a significant amount of the code was working with
six_lock_state as a u64/atomic64_t, and the conversions from the
bitfields to the u64 were deemed a bit too out-there.

More significantly, because bitfield order is poorly defined (#ifdef
__LITTLE_ENDIAN_BITFIELD can be used, but is gross), incrementing the
sequence number would overflow into the rest of the bitfield if the
compiler didn't put the sequence number at the high end of the word.

The new code is a bit saner when we're on an architecture without real
atomic64_t support - all accesses to lock->state now go through
atomic64_*() operations.

On architectures with real atomic64_t support, we additionally use
atomic bit ops for setting/clearing individual bits.

Text size: 7467 bytes -> 4649 bytes - compilers still suck at
bitfields.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2023-10-22 17:10:02 -04:00
Kent Overstreet
3d86f13df6 bcachefs: Improve trans_restart_split_race tracepoint
Seeing occasional test failures where we get stuck in a livelock that
involves this event - this will help track it down.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2023-10-22 17:09:58 -04:00
Kent Overstreet
abab7609de bcachefs: Fix bch2_extent_fallocate() in nocow mode
When we allocate disk space, we need to be incrementing the WRITE io
clock, which perhaps should be renamed to sectors allocated - copygc
uses this io clock to know when to run.

Also, we should be incrementing the same clock when allocating btree
nodes.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2023-10-22 17:09:57 -04:00
Kent Overstreet
65d48e3525 bcachefs: Private error codes: ENOMEM
This adds private error codes for most (but not all) of our ENOMEM uses,
which makes it easier to track down assorted allocation failures.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2023-10-22 17:09:57 -04:00
Kent Overstreet
ac2ccddc26 bcachefs: Drop some anonymous structs, unions
Rust bindgen doesn't cope well with anonymous structs and unions. This
patch drops the fancy anonymous structs & unions in bkey_i that let us
use the same helpers for bkey_i and bkey_packed; since bkey_packed is an
internal type that's never exposed to outside code, it's only a minor
inconvenienc.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2023-10-22 17:09:55 -04:00
Kent Overstreet
45dd05b3ec bcachefs: BKEY_PADDED_ONSTACK()
Rust bindgen doesn't do anonymous structs very nicely: BKEY_PADDED()
only needs the anonymous struct when it's used on the stack, to
guarantee layout, not when it's embedded in another struct.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2023-10-22 17:09:55 -04:00
Kent Overstreet
1306f87de3 bcachefs: Plumb btree_trans through btree cache code
Soon, __bch2_btree_node_write() is going to require a btree_trans: zoned
device support is going to require a new allocation for every btree node
write. This is a bit of prep work.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2023-10-22 17:09:55 -04:00
Kent Overstreet
e151580d30 bcachefs: Add tracepoint & counter for btree split race
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2023-10-22 17:09:54 -04:00
Kent Overstreet
9f6db1276c bcachefs: bch2_journal_entries_postprocess()
This brings back journal_entries_compact(), but in a more efficient form
- we need to do multiple postprocess steps, so iterate over the
journal entries being written just once to make it more efficient.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2023-10-22 17:09:54 -04:00
Kent Overstreet
a1f26d700a bcachefs: Handle btree node rewrites before going RW
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2023-10-22 17:09:52 -04:00
Kent Overstreet
12795a1937 bcachefs: Add some logging for btree node rewrites due to errors
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2023-10-22 17:09:52 -04:00
Kent Overstreet
d94189ad56 bcachefs: Debug mode for c->writes references
This adds a debug mode where we split up the c->writes refcount into
distinct refcounts for every codepath that takes a reference, and adds
sysfs code to print the value of each ref.

This will make it easier to debug shutdown hangs due to refcount leaks.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2023-10-22 17:09:50 -04:00
Kent Overstreet
06ab86d596 bcachefs: Fix btree_node_write_blocked() not being cleared
The btree_node_write_blocked bit was a later addition to this code,
it only mirrors the state of the b->write_blocked list (empty or
nonempty) - unfortunately, when it was added it wasn't correctly kept in
sync - oops.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2023-10-22 17:09:50 -04:00
Kent Overstreet
adf6360b5d bcachefs: Improve btree_reserve_get_fail tracepoint
Now we include the return code.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2023-10-22 17:09:49 -04:00
Kent Overstreet
87ced107f3 bcachefs: Convert EAGAIN errors to private error codes
More error code cleanup, for better error messages and debugability.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2023-10-22 17:09:49 -04:00
Kent Overstreet
ee2c6ea776 bcachefs: btree_iter->ip_allocated
In debug mode, we now track where btree iterators and paths are
initialized/allocated - helpful in tracking down btree path overflows.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2023-10-22 17:09:49 -04:00
Kent Overstreet
e88a75ebe8 bcachefs: New bpos_cmp(), bkey_cmp() replacements
This patch introduces
 - bpos_eq()
 - bpos_lt()
 - bpos_le()
 - bpos_gt()
 - bpos_ge()

and equivalent replacements for bkey_cmp().

Looking at the generated assembly these could probably be improved
further, but we already see a significant code size improvement with
this patch.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2023-10-22 17:09:47 -04:00
Kent Overstreet
42af0ad569 bcachefs: Fix a race with b->write_type
b->write_type needs to be set atomically with setting the
btree_node_need_write flag, so move it into b->flags.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2023-10-22 17:09:46 -04:00
Kent Overstreet
4fcdd6ec34 bcachefs: Btree split improvement
This improves the bkey_format calculation when splitting btree nodes.
Previously, we'd use a format calculated for the original node for the
lower of the two new nodes.

This was particularly bad on sequential insertions, where we iteratively
split the last btree node, whos format has to include KEY_MAX.

Now, we calculate formats precisely for the keys the two new nodes will
contain. This also should make splitting a bit more efficient, since
we're only copying keys once (from the original node to the new node,
instead of new node, replacement node, then upper split).

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2023-10-22 17:09:46 -04:00
Kent Overstreet
46fee692ee bcachefs: Improved btree write statistics
This replaces sysfs btree_avg_write_size with btree_write_stats, which
now breaks out statistics by the source of the btree write.

Btree writes that are too small are a source of inefficiency, and
excessive btree resort overhead - this will let us see what's causing
them.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2023-10-22 17:09:45 -04:00
Kent Overstreet
df6a24f81a bcachefs: Make error messages more uniform
Use __func__ in error messages that refer to function name, and do so
more uniformly - suggested by checkpatch.pl

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2023-10-22 17:09:45 -04:00
Kent Overstreet
3e3e02e6bc bcachefs: Assorted checkpatch fixes
checkpatch.pl gives lots of warnings that we don't want - suggested
ignore list:

 ASSIGN_IN_IF
 UNSPECIFIED_INT	- bcachefs coding style prefers single token type names
 NEW_TYPEDEFS		- typedefs are occasionally good
 FUNCTION_ARGUMENTS	- we prefer to look at functions in .c files
			  (hopefully with docbook documentation), not .h
			  file prototypes
 MULTISTATEMENT_MACRO_USE_DO_WHILE
			- we have _many_ x-macros and other macros where
			  we can't do this

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2023-10-22 17:09:44 -04:00
Kent Overstreet
de107dc800 bcachefs: Call bch2_btree_update_add_new_node() before dropping write lock
btree nodes can be written by other threads (shrinker, journal reclaim)
with only a read lock, but brand new nodes should only be written by the
thread doing the split/interior update. bch2_btree_update_add_new_node()
sets btree node flags to indicate that this is a new node and should not
be written out by other threads, thus we need to call it before dropping
our write lock.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2023-10-22 17:09:43 -04:00
Kent Overstreet
1f0f731ffe bcachefs: Btree splits now only take the locks they need
Previously, bch2_btree_update_start() would always take all intent
locks, all the way up to the root.

We've finally got data from users where this became a scalability issue
- so, this patch fixes bch2_btree_update_start() to only take the locks
we need.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2023-10-22 17:09:43 -04:00
Kent Overstreet
1ff7849f3b bcachefs: bch2_btree_insert_node() no longer uses lock_write_nofail
Now that we have an error path plumbed through, there's no need to be
using bch2_btree_node_lock_write_nofail().

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2023-10-22 17:09:43 -04:00
Kent Overstreet
a8eefbd324 bcachefs: Add error path to btree_split()
The next patch in the series is (finally!) going to change btree splits
(and interior updates in general) to not take intent locks all the way
up to the root - instead only locking the nodes they'll need to modify.

However, this will be introducing a race since if we're not holding a
write lock on a btree node it can be written out by another thread, and
then we might not have enough space for a new bset entry.

We can handle this by retrying - we just need to introduce a new error
path.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2023-10-22 17:09:43 -04:00
Kent Overstreet
8cbb000250 bcachefs: Write new btree nodes after parent update
In order to avoid locking all btree nodes up to the root for btree node
splits, we're going to have to introduce a new error path into
bch2_btree_insert_node(); this mean we can't have done any writes or
modified global state before that point.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2023-10-22 17:09:43 -04:00
Kent Overstreet
8aaee94d46 bcachefs: Fix a deadlock in btree_update_nodes_written()
btree_node_lock_nopath() is something we'd like to get rid of, it's
always prone to deadlocks if we accidentally are holding other locks,
because it doesn't mark the lock it's taking in a path: we'll want to
get rid of it in the future, but for now this patch works it by calling
bch2_trans_unlock().

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2023-10-22 17:09:42 -04:00
Kent Overstreet
c298fd7d34 bcachefs; Mark __bch2_trans_iter_init as inline
This function is fairly small and only used in two places: one very hot,
the other cold, so it should definitely be inlined.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2023-10-22 17:09:42 -04:00
Kent Overstreet
c6cf49a95a bcachefs: Fix blocking with locks held
This is a major oopsy - we should always be unlocking before calling
closure_sync(), else we'll cause a deadlock.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2023-10-22 17:09:41 -04:00
Kent Overstreet
01ed3359b2 bcachefs: btree_update_nodes_written() needs BTREE_INSERT_USE_RESERVE
This fixes an obvious deadlock - whoops.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2023-10-22 17:09:41 -04:00
Kent Overstreet
d602657cd1 bcachefs: Fix error handling in bch2_btree_update_start()
We were checking for -EAGAIN, but we're not returned that when we didn't
pass a closure to wait with - oops.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2023-10-22 17:09:41 -04:00
Kent Overstreet
e4215d0fec bcachefs: All held locks must be in a btree path
With the new deadlock cycle detector, it's critical that all held locks
be marked in a btree_path, because that's what the cycle detector
traverses - any locks that aren't correctly marked will cause deadlocks.

This changes the btree_path to allocate some btree_paths for the new
nodes, since until the final update is done we otherwise don't have a
path referencing them.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2023-10-22 17:09:40 -04:00
Kent Overstreet
367d72dd5f bcachefs: bch2_btree_path_upgrade() now emits transaction restart
Centralizing the transaction restart/tracepoint in
bch2_btree_path_upgrade() lets us improve the tracepoint - now it emits
old and new locks_want.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2023-10-22 17:09:40 -04:00
Kent Overstreet
38474c2642 bcachefs: Avoid using btree_node_lock_nopath()
With the upcoming cycle detector, we have to be careful about using
btree_node_lock_nopath - in particular, using it to take write locks can
cause deadlocks.

All held locks need to be tracked in a btree_path, so that the cycle
detector knows about them - unless we know that we cannot cause
deadlocks for other reasons: e.g. we are only taking read locks, or
we're in very early fsck (topology repair).

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2023-10-22 17:09:40 -04:00
Kent Overstreet
da4474f209 bcachefs: Convert more locking code to btree_bkey_cached_common
Ideally, all the code in btree_locking.c should be converted, but then
we'd want to convert btree_path to point to btree_key_cached_common too,
and then we'd be in for a much bigger cleanup - but a bit of incremental
cleanup will still be helpful for the next patches.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2023-10-22 17:09:40 -04:00
Kent Overstreet
d5024b011c bcachefs: bch2_btree_node_lock_write_nofail()
Taking a write lock will be able to fail, with the new cycle detector -
unless we pass it nofail, which is possible but not preferred.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2023-10-22 17:09:40 -04:00
Kent Overstreet
ca7d8fcabf bcachefs: New locking functions
In the future, with the new deadlock cycle detector, we won't be using
bare six_lock_* anymore: lock wait entries will all be embedded in
btree_trans, and we will need a btree_trans context whenever locking a
btree node.

This patch plumbs a btree_trans to the few places that need it, and adds
two new locking functions
 - btree_node_lock_nopath, which may fail returning a transaction
   restart, and
 - btree_node_lock_nopath_nofail, to be used in places where we know we
   cannot deadlock (i.e. because we're holding no other locks).

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
2023-10-22 17:09:40 -04:00