If the reader acquires the read lock and then the writer enters the slow
path, while the reader proceeds to the unlock path, the following scenario
can occur without the change:

writer: pcpu_read_count(lock) return 1 (so __do_six_trylock will return 0)
reader: this_cpu_dec(*lock->readers)
reader: smp_mb()
reader: state = atomic_read(&lock->state) (there is no waiting flag set)
writer: six_set_bitmask()

then the writer will sleep forever.
Signed-off-by: Alan Huang <mmpgouride@gmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

If we shut down successfully, there shouldn't be any logged ops to
resume.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

Add a filesystem flag to indicate whether we did a clean recovery -
using c->sb.clean after we've got rw is incorrect, since c->sb is
updated whenever we write the superblock.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

We had a bug where disk accounting keys didn't always have their version
field set in journal replay; change the BUG_ON() to a WARN(), and
exclude this case since it's now checked for elsewhere (in the bkey
validate function).
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

This was added to avoid double-counting accounting keys in journal
replay. But applied incorrectly (easily done since it applies to the
transaction commit, not a particular update), it leads to skipping
in-mem accounting for real accounting updates, and failure to give them
a version number - which leads to journal replay becoming very confused
the next time around.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

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

give bversions a more distinct name, to aid in grepping
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

Previously, check_inode() would delete unlinked inodes if they weren't
on the deleted list - this code dating from before there was a deleted
list.

But, if we crash during a logged op (truncate or finsert/fcollapse) of
an unlinked file, logged op resume will get confused if the inode has
already been deleted - instead, just add it to the deleted list if it
needs to be there; delete_dead_inodes runs after logged op resume.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

BCH_SB_ERRS() has a field for the actual enum val so that we can reorder
to reorganize, but the way BCH_SB_ERR_MAX was defined didn't allow for
this.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

__bch2_fsck_err() warns if the current task has a btree_trans object and
it wasn't passed in, because if it has to prompt for user input it has
to be able to unlock it.

But plumbing the btree_trans through bkey_validate(), as well as
transaction restarts, is problematic - so instead make bkey fsck errors
FSCK_AUTOFIX, which doesn't need to warn.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

In order to check for accounting keys with version=0, we need to run
validation after they've been assigned version numbers.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

This fixes the following bug, where a disk accounting key has an invalid
replicas entry, and we attempt to add it to the superblock:

bcachefs (3c0860e8-07ca-4276-8954-11c1774be868): starting version 1.12: rebalance_work_acct_fix opts=metadata_replicas=2,data_replicas=2,foreground_target=ssd,background_target=hdd,nopromote_whole_extents,verbose,fsck,fix_errors=yes
bcachefs (3c0860e8-07ca-4276-8954-11c1774be868): recovering from clean shutdown, journal seq 15211644
bcachefs (3c0860e8-07ca-4276-8954-11c1774be868): accounting_read...
accounting not marked in superblock replicas
  replicas cached: 1/1 [0], fixing
bcachefs (3c0860e8-07ca-4276-8954-11c1774be868): sb invalid before write: Invalid superblock section replicas_v0: invalid device 0 in entry cached: 1/1 [0]
replicas_v0 (size 88):
user: 2 [3 5] user: 2 [1 4] cached: 1 [2] btree: 2 [1 2] user: 2 [2 5] cached: 1 [0] cached: 1 [4] journal: 2 [1 5] user: 2 [1 2] user: 2 [2 3] user: 2 [3 4] user: 2 [4 5] cached: 1 [1] cached: 1 [3] cached: 1 [5] journal: 2 [1 2] journal: 2 [2 5] btree: 2 [2 5] user: 2 [1 3] user: 2 [1 5] user: 2 [2 4]

bcachefs (3c0860e8-07ca-4276-8954-11c1774be868): inconsistency detected - emergency read only at journal seq 15211644
accounting not marked in superblock replicas
  replicas user: 1/1 [3], fixing
bcachefs (3c0860e8-07ca-4276-8954-11c1774be868): sb invalid before write: Invalid superblock section replicas_v0: invalid device 0 in entry cached: 1/1 [0]
replicas_v0 (size 96):
user: 2 [3 5] user: 2 [1 3] cached: 1 [2] btree: 2 [1 2] user: 2 [2 4] cached: 1 [0] cached: 1 [4] journal: 2 [1 5] user: 1 [3] user: 2 [1 5] user: 2 [3 4] user: 2 [4 5] cached: 1 [1] cached: 1 [3] cached: 1 [5] journal: 2 [1 2] journal: 2 [2 5] btree: 2 [2 5] user: 2 [1 2] user: 2 [1 4] user: 2 [2 3] user: 2 [2 5]

accounting not marked in superblock replicas
  replicas user: 1/2 [3 7], fixing
bcachefs (3c0860e8-07ca-4276-8954-11c1774be868): sb invalid before write: Invalid superblock section replicas_v0: invalid device 7 in entry user: 1/2 [3 7]
replicas_v0 (size 96):
user: 2 [3 7] user: 2 [1 3] cached: 1 [2] btree: 2 [1 2] user: 2 [2 4] cached: 1 [0] cached: 1 [4] journal: 2 [1 5] user: 1 [3] user: 2 [1 5] user: 2 [3 4] user: 2 [4 5] cached: 1 [1] cached: 1 [3] cached: 1 [5] journal: 2 [1 2] journal: 2 [2 5] btree: 2 [2 5] user: 2 [1 2] user: 2 [1 4] user: 2 [2 3] user: 2 [2 5] user: 2 [3 5]

 done
bcachefs (3c0860e8-07ca-4276-8954-11c1774be868): alloc_read... done
bcachefs (3c0860e8-07ca-4276-8954-11c1774be868): stripes_read... done
bcachefs (3c0860e8-07ca-4276-8954-11c1774be868): snapshots_read... done
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

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

accounting read was checking if accounting replicas entries were marked
in the superblock prior to applying accounting from the journal,
which meant that a recently removed device could spuriously trigger a
"not marked in superblocked" error (when journal entries zero out the
offending counter).
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

Minor refactoring - replace multiple bool arguments with an enum; prep
work for fixing a bug in accounting read.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

Dealing with outside state within a btree transaction is always tricky.

check_extents() and check_dirents() have to accumulate counters for
i_sectors and i_nlink (for subdirectories). There were two bugs:

- transaction commit may return a restart; therefore we have to commit
  before accumulating to those counters
- get_inode_all_snapshots() may return a transaction restart, before
  updating w->last_pos; then, on the restart,
  check_i_sectors()/check_subdir_count() would see inodes that were not
  for w->last_pos
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

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

Returning a positive integer instead of an error code causes error paths
to become very confused.

Closes: syzbot+c0360e8367d6d8d04a66@syzkaller.appspotmail.com
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

The pointer clean points the memory allocated by kmemdup, when the
return value of bch2_sb_clean_validate_late is not zero. The memory
pointed by clean is leaked. So we should free it in this case.

Fixes: a37ad1a3 ("bcachefs: sb-clean.c")
Signed-off-by: Hongbo Li <lihongbo22@huawei.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

In downgrade_table_extra, the return value is needed. When it
return failed, we should exit immediately.

Fixes: 7773df19 ("bcachefs: metadata version bucket_stripe_sectors")
Signed-off-by: Hongbo Li <lihongbo22@huawei.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

A couple small error handling fixes
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

this allows for various cleanups in fsck
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

syzbot reported a null ptr deref in __copy_user [0]

In __bch2_read_super, when a corrupt backup superblock matches the
default opts offset, no error is assigned to ret and the freed superblock
gets through, possibly being assigned as the best sb in bch2_fs_open and
being later dereferenced, causing a fault. Assign EINVALID to ret when
iterating through layout.

[0]: https://syzkaller.appspot.com/bug?extid=18a5c5e8a9c856944876

Reported-by: syzbot+18a5c5e8a9c856944876@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=18a5c5e8a9c856944876Signed-off-by: Diogo Jahchan Koike <djahchankoike@gmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

check_topology doesn't need the srcu lock and doesn't use normal btree
transactions - we can just drop the srcu lock.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

fsck_err() jumps to the fsck_err label when bailing out; need to make
sure bp_iter was initialized...
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

Zero-initialize part of allocated bounce buffer which wasn't touched by
subsequent bch2_key_sort_fix_overlapping to mitigate later uinit-value
use KMSAN bug[1].

After applying the patch reproducer still triggers stack overflow[2] but
it seems unrelated to the uninit-value use warning. After further
investigation it was found that stack overflow occurs because KMSAN adds
too many function calls[3]. Backtrace of where the stack magic number gets
smashed was added as a reply to syzkaller thread[3].

It was confirmed that task's stack magic number gets smashed after the code
path where KSMAN detects uninit-value use is executed, so it can be assumed
that it doesn't contribute in any way to uninit-value use detection.

[1] https://syzkaller.appspot.com/bug?extid=6f655a60d3244d0c6718
[2] https://lore.kernel.org/lkml/66e57e46.050a0220.115905.0002.GAE@google.com
[3] https://lore.kernel.org/all/rVaWgPULej8K7HqMPNIu8kVNyXNjjCiTB-QBtItLFBmk0alH6fV2tk4joVPk97Evnuv4ZRDd8HB5uDCkiFG6u81xKdzDj-KrtIMJSlF6Kt8=@proton.me

Reported-by: syzbot+6f655a60d3244d0c6718@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=6f655a60d3244d0c6718
Fixes: ec4edd7b ("bcachefs: Prep work for variable size btree node buffers")
Suggested-by: Kent Overstreet <kent.overstreet@linux.dev>
Signed-off-by: Piotr Zalewski <pZ010001011111@proton.me>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

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

This fixes a kasan splat in propagate_key_to_snapshot_leaves() -
varint_decode_fast() does reads (that it never uses) up to 7 bytes past
the end of the integer.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

Most or all errors will be autofix in the future, we're currently just
doing the ones that we know are well tested.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

As we iterate we need to mark that we no longer need iterators -
otherwise we'll infinite loop via the "too many iters" check when
there's many snapshots.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

if it doesn't get set we'll never be able to flush the btree write
buffer; this only happens in fake rw mode, but prevents us from shutting
down.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

Syzbot reports a problem that a warning is triggered due to suspicious
use of rcu_dereference_check(). That is triggered by a call of
bch2_snapshot_tree_oldest_subvol().

The cause of the warning is that inside
bch2_snapshot_tree_oldest_subvol(), snapshot_t() is called which calls
rcu_dereference() that requires a read lock to be held. Also, the call
of bch2_snapshot_tree_next() eventually calls snapshot_t().

To fix this, call rcu_read_lock() before calling snapshot_t(). Then,
release the lock after the termination of the while loop.

Reported-by: <syzbot+f7c41a878676b72c16a6@syzkaller.appspotmail.com>
Signed-off-by: Ahmed Ehab <bottaawesome633@gmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

syzbot reported a null-ptr-deref in bch2_fs_start. [0]

When a sb is marked clear but doesn't have a clean section
bch2_read_superblock_clean returns NULL which PTR_ERR_OR_ZERO
lets through, eventually leading to a null ptr dereference down
the line. Adjust read sb clean to return an ERR_PTR indicating the
invalid clean section.

[0] https://syzkaller.appspot.com/bug?extid=1cecc37d87c4286e5543

Reported-by: syzbot+1cecc37d87c4286e5543@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=1cecc37d87c4286e5543Signed-off-by: Diogo Jahchan Koike <djahchankoike@gmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

The header files bbpos.h is included twice in backpointers.c,
so one inclusion of each can be removed.
Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Closes: https://bugzilla.openanolis.cn/show_bug.cgi?id=10783Signed-off-by: Yang Li <yang.lee@linux.alibaba.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

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

This factors out ec_strie_head_devs_update(), which initializes the
bitmap of devices we're allocating from, and runs it every time
c->rw_devs_change_count changes.

We also cancel pending, not allocated stripes, since they may refer to
devices that are no longer available.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

Add a counter that's incremented whenever rw devices change; this will
be used for erasure coding so that it can keep ec_stripe_head in sync
and not deadlock on a new stripe when a device it wants goes away.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

We can now correctly force-remove a device that has stripes on it; this
uses the new BCH_SB_MEMBER_INVALID sentinal value.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

This is necessary for erasure coded pointers to devices that have been
removed.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

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