Kent Overstreet [Thu, 12 Dec 2024 08:03:58 +0000 (03:03 -0500)]
bcachefs: Snapshot deletion no longer uses snapshot_t->equiv
Switch to generating a private list of interior nodes to delete, instead
of using the equivalence class in the global data structure.
This eliminates possible races with snapshot creation, and is much
cleaner - it'll let us delete a lot of janky code for calculating and
maintaining the equivalence classes.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Kent Overstreet [Thu, 12 Dec 2024 07:41:37 +0000 (02:41 -0500)]
bcachefs: Kill equiv_seen arg to delete_dead_snapshots_process_key()
When deleting dead snapshots, we move keys from redundant interior
snapshot nodes to child nodes - unless there's already a key, in which
case the ancestor key is deleted.
Previously, we tracked via equiv_seen whether the child snapshot had a
key, but this was tricky w.r.t. transaction restarts, and not
transactionally safe w.r.t. updates in the child snapshot.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Kent Overstreet [Thu, 12 Dec 2024 07:32:32 +0000 (02:32 -0500)]
bcachefs: alloc_data_type_set() happens in alloc trigger
Originally, we ran insert triggers before overwrite so that if an extent
was being moved (by fallocate insert/collapse range), the bucket sector
count wouldn't hit 0 partway through, and so we don't trigger state
changes caused by that too soon.
But this is better solved by just moving the data type change to the
alloc trigger itself, where it's already called.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Normally, whitouts (KEY_TYPE_whitout) are filtered from btree lookups,
since they exist only to represent deletions of keys in ancestor
snapshots - except, they should not be filtered in
BTREE_ITER_all_snapshots mode, so that e.g. snapshot deletion can clean
them up.
This means that that the key cache has to store whiteouts, and key cache
fills cannot filter them.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
In BTREE_ITER_all_snapshots mode, we're required to only return keys
where the snapshot field matches the iterator position -
BTREE_ITER_filter_snapshots requires pulling keys into the key cache
from ancestor snapshots, so we have to check for that.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Nathan Chancellor [Tue, 10 Dec 2024 18:12:07 +0000 (11:12 -0700)]
bcachefs: Add empty statement between label and declaration in check_inode_hash_info_matches_root()
Clang 18 and newer warns (or errors with CONFIG_WERROR=y):
fs/bcachefs/str_hash.c:164:2: error: label followed by a declaration is a C23 extension [-Werror,-Wc23-extensions]
164 | struct bch_inode_unpacked inode;
| ^
In Clang 17 and prior, this is an unconditional hard error:
fs/bcachefs/str_hash.c:164:2: error: expected expression
164 | struct bch_inode_unpacked inode;
| ^
fs/bcachefs/str_hash.c:165:30: error: use of undeclared identifier 'inode'
165 | ret = bch2_inode_unpack(k, &inode);
| ^
fs/bcachefs/str_hash.c:169:55: error: use of undeclared identifier 'inode'
169 | struct bch_hash_info hash2 = bch2_hash_info_init(c, &inode);
| ^
fs/bcachefs/str_hash.c:171:40: error: use of undeclared identifier 'inode'
171 | ret = repair_inode_hash_info(trans, &inode);
| ^
Add an empty statement between the label and the declaration to fix the
warning/error without disturbing the code too much.
Fixes: 2519d3b0d656 ("bcachefs: bch2_str_hash_check_key() now checks inode hash info") Reported-by: kernel test robot <lkp@intel.com> Closes: https://lore.kernel.org/oe-kbuild-all/202412092339.QB7hffGC-lkp@intel.com/ Signed-off-by: Nathan Chancellor <nathan@kernel.org> Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Kent Overstreet [Mon, 9 Dec 2024 02:47:34 +0000 (21:47 -0500)]
bcachefs: bch2_str_hash_check_key() now checks inode hash info
Versions of the same inode in different snapshots must have the same
hash info; this is critical for lookups to work correctly.
We're going to be running the str_hash checks online, at readdir or
xattr list time, so we now need str_hash_check_key() to check for inode
hash seed mismatches, since it won't be run right after check_inodes().
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Kent Overstreet [Mon, 9 Dec 2024 03:00:36 +0000 (22:00 -0500)]
bcachefs: Don't BUG_ON() inode unpack error
Bkey validation checks that inodes are well-formed and unpack
successfully, so an unpack error should always indicate memory
corruption or some other kind of hardware bug - but these are still
errors we can recover from.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Kent Overstreet [Sun, 8 Dec 2024 09:11:21 +0000 (04:11 -0500)]
bcachefs: Kill unnecessary mark_lock usage
We can't hold mark_lock while calling fsck_err() - that's a deadlock,
mark_lock is meant to be a leaf node lock.
It's also unnecessary for gc_bucket() and bucket_gen(); rcu suffices
since the bucket_gens array describes its size, and we can't race with
device removal or resize during gc/fsck since that takes state lock.
Reported-by: syzbot+38641fcbda1aaffefdd4@syzkaller.appspotmail.com Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Kent Overstreet [Sat, 7 Dec 2024 04:15:05 +0000 (23:15 -0500)]
bcachefs: Fix reuse of bucket before journal flush on multiple empty -> nonempty transition
For each bucket we track when the bucket became nonempty and when it
became empty again: if we can ensure that there will be no journal
flushes in the range [nonempty, empty) (possibly because they occured at
the same journal sequence number), then it's safe to reuse the bucket
without waiting for a journal commit.
This is a major performance optimization for erasure coding, where
writes are initially replicated, but the extra replicas are quickly
dropped: if those buckets are reused and overwritten without issuing a
cache flush to the underlying device, then they only cost bus bandwidth.
But there's a tricky corner case when there's multiple empty -> nonempty
-> empty transitions in quick succession, i.e. when data is getting
overwritten immediately as it's being written.
If this happens and the previous empty transition hasn't been flushed,
we need to continue tracking the previous nonempty transition - not
start a new one.
Fixing this means we now need to track both the nonempty and empty
transitions in bch_alloc_v4.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Kent Overstreet [Sun, 8 Dec 2024 05:28:16 +0000 (00:28 -0500)]
bcachefs: bch2_journal_noflush_seq() now takes [start, end)
Harder to screw up if we're explicit about the range, and more correct
as journal reservations can be outstanding on multiple journal entries
simultaneously.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Kent Overstreet [Sat, 7 Dec 2024 00:23:22 +0000 (19:23 -0500)]
bcachefs: Use a heap for handling overwrites in btree node scan
Fix an O(n^2) issue when we find many overlapping (overwritten) btree
nodes - especially when one node overwrites many smaller nodes.
This was discovered to be an issue with the bcachefs
merge_torture_flakey test - if we had a large btree that was then
emptied, the number of difficult overwrites can be unbounded.
Cc: Kuan-Wei Chiu <visitorckw@gmail.com> Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Kent Overstreet [Sat, 7 Dec 2024 00:16:02 +0000 (19:16 -0500)]
lib min_heap: Switch to size_t
size_t is the correct type for a count of objects that can fit in
memory: this also means heaps now have the same memory layout as darrays
(fs/bcachefs/darray.h), and darrays can be used as heaps.
Cc: Kuan-Wei Chiu <visitorckw@gmail.com> Cc: Ian Rogers <irogers@google.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Coly Li <colyli@suse.de> Cc: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Kent Overstreet [Thu, 5 Dec 2024 01:43:01 +0000 (20:43 -0500)]
bcachefs: Don't call bch2_btree_interior_update_will_free_node() until after update succeeds
Originally, btree splits always succeeded once we got to the point of
recursing to the btree_insert_node() call.
But that changed when we switched to not taking intent locks all the way
up to the root, and that introduced a bug, because
bch2_btree_interior_update_will_free_node() cancels paending writes and
reparents a node that's going to be made visible on disk by another
btree update to the current btree update.
This was discovered in recent backpointers work, because
bch2_btree_interior_update_will_free_node() also clears the
will_make_reachable flag, causing backpointer target lookup to
spuriously thing it had found a dangling backpointer (when the
backpointer just hadn't been created yet by
btree_update_nodes_written()).
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Kent Overstreet [Tue, 3 Dec 2024 04:36:38 +0000 (23:36 -0500)]
bcachefs: Fix allocating too big journal entry
The "journal space available" calculations didn't take into account
mismatched bucket sizes; we need to take the minimum space available out
of our devices.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Yang Li [Fri, 29 Nov 2024 06:38:27 +0000 (14:38 +0800)]
bcachefs: Add missing parameter description to bch2_bucket_alloc_trans()
The function bch2_bucket_alloc_trans() lacked a description for the
nowait parameter in its documentation comment block. This patch adds the
missing description to ensure all parameters are properly documented.
Reported-by: Abaci Robot <abaci@linux.alibaba.com> Closes: https://bugzilla.openanolis.cn/show_bug.cgi?id=12179 Signed-off-by: Yang Li <yang.lee@linux.alibaba.com> Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Kent Overstreet [Thu, 28 Nov 2024 22:57:55 +0000 (17:57 -0500)]
bcachefs: cryptographic MACs on superblock are not (yet?) supported
We should add support for cryptographic macs on the superblock - and it
won't be hard, but it'll need an incompatible feature bit (and we have a
new incompatible feature versioning scheme coming).
For now, just add a guard to avoid a dull ptr deref in gen_poly_key().
Reported-by: syzbot+dd3d9835055dacb66f35@syzkaller.appspotmail.com Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Kent Overstreet [Thu, 28 Nov 2024 02:58:43 +0000 (21:58 -0500)]
bcachefs: Guard against journal seq overflow
Wraparound is impractical to handle since in various places we use 0 as
a sentinal value - but 64 bits (or 56, because the btree write buffer
steals a few bits) is enough for all practical purposes.
Reported-by: syzbot+73ed43fbe826227bd4e0@syzkaller.appspotmail.com Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Kent Overstreet [Wed, 27 Nov 2024 05:29:52 +0000 (00:29 -0500)]
bcachefs: struct bkey_validate_context
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>
Kent Overstreet [Wed, 27 Nov 2024 03:59:27 +0000 (22:59 -0500)]
bcachefs: Fix null ptr deref in btree_path_lock_root()
Historically, we required that all btree node roots point to a valid
(possibly fake) node, but we're improving our ability to continue in the
presence of errors.
Reported-by: syzbot+e22007d6acb9c87c2362@syzkaller.appspotmail.com Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Kent Overstreet [Wed, 27 Nov 2024 02:27:16 +0000 (21:27 -0500)]
bcachefs: Go RW earlier, for normal rw mount
Previously, when mounting read-write after a clean shutdown, we wouldn't
go read-write until after all the recovery passes completed.
Now, go RW early in recovery, the same as any other situation we'll need
to go read-write. This fixes a bug where we discover unlinked inodes
after a clean shutdown: repair fails because we're read only.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Kent Overstreet [Mon, 25 Nov 2024 22:03:13 +0000 (17:03 -0500)]
bcachefs: Change "disk accounting version 0" check to commit only
6.11 had a bug where we'd sometimes create disk accounting keys with
version 0, which causes issues for journal replay - but we don't need to
delete existing accounting keys with version 0.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Kent Overstreet [Mon, 25 Nov 2024 04:28:21 +0000 (23:28 -0500)]
bcachefs: Kill bch2_bucket_alloc_new_fs()
The early-early allocation path, bch2_bucket_alloc_new_fs(), is no
longer needed - and inconsistencies around new_fs_bucket_idx have been a
frequent source of bugs.
Reported-by: syzbot+592425844580a6598410@syzkaller.appspotmail.com Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Kent Overstreet [Fri, 22 Nov 2024 01:09:45 +0000 (20:09 -0500)]
bcachefs: discard fastpath now uses bch2_discard_one_bucket()
The discard bucket fastpath previously was using its own code for
discarding buckets and clearing them in the need_discard btree, which
didn't have any of the consistency checks of the main discard path.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
bch_backpointer.bucket_offset is going away - it's no longer needed
since we no longer store backpointers in alloc keys, the same
information is in the key position itself.
And we'll be reclaiming the space in bch_backpointer for the bucket
generation number.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Kent Overstreet [Mon, 18 Nov 2024 05:32:57 +0000 (00:32 -0500)]
bcachefs: Fix check_backpointers_to_extents range limiting
bch2_get_btree_in_memory_pos() will return positions that refer directly
to the btree it's checking will fit in memory - i.e. backpointer
positions, not buckets.
This also means check_bp_exists() no longer has to refer to the device,
and we can delete some code.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Kent Overstreet [Fri, 15 Nov 2024 22:36:09 +0000 (17:36 -0500)]
bcachefs: bch_backpointer -> bkey_i_backpointer
Since we no longer store backpointers in alloc keys, there's no reason
not to pass around bkey_i_backpointers; this means we don't have to pass
the bucket pos separately.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>