linux-stable.git/fs/bcachefs, branch linux-6.10.y

bcachefs: Don't delete open files in online fsck

2024-09-18T17:25:13+00:00

[ Upstream commit 16005147cca41a0f67b5def2a4656286f8c0db4a ]

If a file is unlinked but still open, we don't want online fsck to
delete it - or fun inconsistencies will happen.

https://github.com/koverstreet/bcachefs/issues/727

Signed-off-by: Kent Overstreet 
Signed-off-by: Greg Kroah-Hartman

bcachefs: Revert lockless buffered IO path

2024-09-18T17:25:13+00:00

[ Upstream commit  e3e6940940910c2287fe962bdf72015efd4fee81 ]

We had a report of data corruption on nixos when building installer
images.

https://github.com/NixOS/nixpkgs/pull/321055#issuecomment-2184131334

It seems that writes are being dropped, but only when issued by QEMU,
and possibly only in snapshot mode. It's undetermined if it's write
calls are being dropped or dirty folios.

Further testing, via minimizing the original patch to just the change
that skips the inode lock on non appends/truncates, reveals that it
really is just not taking the inode lock that causes the corruption: it
has nothing to do with the other logic changes for preserving write
atomicity in corner cases.

It's also kernel config dependent: it doesn't reproduce with the minimal
kernel config that ktest uses, but it does reproduce with nixos's distro
config. Bisection the kernel config initially pointer the finger at page
migration or compaction, but it appears that was erroneous; we haven't
yet determined what kernel config option actually triggers it.

Sadly it appears this will have to be reverted since we're getting too
close to release and my plate is full, but we'd _really_ like to fully
debug it.

My suspicion is that this patch is exposing a preexisting bug - the
inode lock actually covers very little in IO paths, and we have a
different lock (the pagecache add lock) that guards against races with
truncate here.

Fixes: 7e64c86cdc6c ("bcachefs: Buffered write path now can avoid the inode lock")
Signed-off-by: Kent Overstreet 
Signed-off-by: Greg Kroah-Hartman

bcachefs: Fix bch2_extents_match() false positive

2024-09-18T17:25:13+00:00

[ Upstream commit  d26935690c03fe8159d42358bed1c56252700cd1 ]

This was caught as a very rare nonce inconsistency, on systems with
encryption and replication (and tiering, or some form of rebalance
operation running):

[Wed Jul 17 13:30:03 2024] about to insert invalid key in data update path
[Wed Jul 17 13:30:03 2024] old: u64s 10 type extent 671283510:6392:U32_MAX len 16 ver 106595503: durability: 2 crc: c_size 8 size 16 offset 0 nonce 0 csum chacha20_poly1305_80 compress zstd ptr: 3:355968:104 gen 7 ptr: 4:513244:48 gen 6 rebalance: target hdd compression zstd
[Wed Jul 17 13:30:03 2024] k:   u64s 10 type extent 671283510:6400:U32_MAX len 16 ver 106595508: durability: 2 crc: c_size 8 size 16 offset 0 nonce 0 csum chacha20_poly1305_80 compress zstd ptr: 3:355968:112 gen 7 ptr: 4:513244:56 gen 6 rebalance: target hdd compression zstd
[Wed Jul 17 13:30:03 2024] new: u64s 14 type extent 671283510:6392:U32_MAX len 8 ver 106595508: durability: 2 crc: c_size 8 size 16 offset 0 nonce 0 csum chacha20_poly1305_80 compress zstd ptr: 3:355968:112 gen 7 cached ptr: 4:513244:56 gen 6 cached rebalance: target hdd compression zstd crc: c_size 8 size 16 offset 8 nonce 0 csum chacha20_poly1305_80 compress zstd ptr: 1:10860085:32 gen 0 ptr: 0:17285918:408 gen 0
[Wed Jul 17 13:30:03 2024] bcachefs (cca5bc65-fe77-409d-a9fa-465a6e7f4eae): fatal error - emergency read only

bch2_extents_match() was reporting true for extents that did not
actually point to the same data.

bch2_extent_match() iterates over pairs of pointers, looking for
pointers that point to the same location on disk (with matching
generation numbers). However one or both extents may have been trimmed
(or merged) and they might not have the same disk offset: it corrects
for this by subtracting the key offset and the checksum entry offset.

However, this failed when an extent was immediately partially
overwritten, and the new overwrite was allocated the next adjacent disk
space.

Normally, with compression off, this would never cause a bug, since the
new extent would have to be immediately after the old extent for the
pointer offsets to match, and the rebalance index update path is not
looking for an extent outside the range of the extent it moved.

However with compression enabled, extents take up less space on disk
than they do in the btree index space - and spuriously matching after
partial overwrite is possible.

To fix this, add a secondary check, that strictly checks that the
regions pointed to on disk overlap.

https://github.com/koverstreet/bcachefs/issues/717

Signed-off-by: Kent Overstreet 
Signed-off-by: Greg Kroah-Hartman

bcachefs: bch2_gc_btree() should not use btree_root_lock

2024-07-12T00:10:55+00:00

btree_root_lock is for the root keys in btree_root, not the pointers to
the nodes themselves; this fixes a lock ordering issue between
btree_root_lock and btree node locks.

Signed-off-by: Kent Overstreet

bcachefs: Set PF_MEMALLOC_NOFS when trans->locked

2024-07-12T00:10:55+00:00

proper lock ordering is: fs_reclaim -> btree node locks

Signed-off-by: Kent Overstreet

bcachefs; Use trans_unlock_long() when waiting on allocator

2024-07-12T00:10:55+00:00

not using unlock_long() blocks key cache reclaim, and the allocator may
take awhile

Signed-off-by: Kent Overstreet

Revert "bcachefs: Mark bch_inode_info as SLAB_ACCOUNT"

2024-07-12T00:01:38+00:00

This reverts commit 86d81ec5f5f05846c7c6e48ffb964b24cba2e669.

This wasn't tested with memcg enabled, it immediately hits a null ptr
deref in list_lru_add().

Signed-off-by: Kent Overstreet

bcachefs: fix scheduling while atomic in break_cycle()

2024-07-10T16:59:28+00:00

Signed-off-by: Kent Overstreet

bcachefs: Fix RCU splat

2024-07-10T16:46:22+00:00

Reported-by: syzbot+e74fea078710bbca6f4b@syzkaller.appspotmail.com
Signed-off-by: Kent Overstreet

bcachefs: Add missing bch2_trans_begin()

2024-07-10T13:53:39+00:00

this fixes a 'transaction should be locked' error in backpointers fsck

Signed-off-by: Kent Overstreet