"bcachefs; Fix deadlock in bch2_btree_update_start()" was a significant
performance regression (nearly 50%) on multithreaded random writes with
fio.

The reason is that the journal watermark checks multiple things,
including the state of the btree write buffer, and on multithreaded
update heavy workloads we're bottleneked on write buffer flushing - we
don't want kicknig off btree updates to depend on the state of the write
buffer.

This isn't strictly correct; the interior btree update path does do
write buffer updates, but it's a tiny fraction of total accounting
updates and we're more concerned with space in the journal itself.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

BCH_IOCTL_FSCK_OFFLINE allows the userspace fsck tool to use the kernel
implementation of fsck - primarily when the kernel version is a better
version match.

It should look and act exactly like the normal userspace fsck that the
user expected to be invoking, so errors should never result in a kernel
panic.

We may want to consider further restricting errors=panic - it's only
intended for debugging in controlled test environments, it should have
no purpose it normal usage.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

To open an encrypted filesystem, we use request_key() to get the
encryption key from the user's keyring - but request_key() needs to
happen in the context of the process that invoked the ioctl.

This easily fixed by using bch2_fs_open() in nostart mode.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

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

The ! was obviously intended to be ~.  As it is, this function does
the equivalent to: "addr[bit / 64] = 0;".

Fixes: 27fcec6c ("bcachefs: Clear recovery_passes_required as they complete without errors")
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

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

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

Print start and end level of the btree update; also a bit of cleanup.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

sysfs is limited to PAGE_SIZE, and when we're debugging strange
deadlocks/priority inversions we need to see the full list.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

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

Snapshot table accesses generally need to be checking for invalid
snapshot ID now, fix one that was missed.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

This creates a subdirectory for each individual btree under the btrees/
debugfs directory.

Directory structure, before:

/sys/kernel/debug/bcachefs/$FS_ID/btrees/
├── alloc
├── alloc-bfloat-failed
├── alloc-formats
├── backpointers
├── backpointers-bfloat-failed
├── backpointers-formats
...

Directory structure, after:

/sys/kernel/debug/bcachefs/$FS_ID/btrees/
├── alloc
│   ├── bfloat-failed
│   ├── formats
│   └── keys
├── backpointers
│   ├── bfloat-failed
│   ├── formats
│   └── keys
...
Signed-off-by: Thomas Bertschinger <tahbertschinger@gmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

If an inode is missing, but corresponding extents and dirent still
exist, it's well worth recreating it - this does so.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

We can now recreate missing subvolumes from dirents and/or inodes.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

In backpointer repair, if we get a missing backpointer - but there's
already a backpointer that points to an existing extent - we've got
multiple extents that point to the same space and need to decide which
to keep.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

When the snapshots btree is going, we'll have to delete huge amounts of
data - unless we can reconstruct it by looking at the keys that refer to
it.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

We need this to know when we should attempt to reconstruct the snapshots
btree
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

With the new btree node scan code, we can now recover from corrupt btree
roots - simply create a new fake root at depth 1, and then insert all
the leaves we found.

If the root wasn't corrupt but there's corruption elsewhere in the
btree, we can fill in holes as needed with the newest version of a given
node(s) from the scan; we also check if a given btree node is older than
what we found from the scan.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

If a btree root or interior btree node goes bad, we're going to lose a
lot of data, unless we can recover the nodes that it pointed to by
scanning.

Fortunately btree node headers are fully self describing, and
additionally the magic number is xored with the filesytem UUID, so we
can do so safely.

This implements the scanning - next patch will rework topology repair to
make use of the found nodes.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

When a btree root is unreadable, we might still have keys fro the
journal to walk and mark.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

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

Pull out eytzinger.c and kill eytzinger_cmp_fn. We now provide
eytzinger0_sort and eytzinger0_sort_r, which use the standard cmp_func_t
and cmp_r_func_t callbacks.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

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

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

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

In the discard worker, we were failing to validate the bucket state -
meaning a corrupt needs_discard btree could cause us to discard a bucket
that we shouldn't.

If check_alloc_info hasn't run yet we just want to bail out, otherwise
it's a filesystem inconsistent error.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

Print out the mode as a string, and also print out the btree and
watermark.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

mean_and_variance_test_2 and mean_and_variance_test_4 always fail.
The input parameters to those tests are identical to the input parameters
to tests 1 and 3, yet the expected result for tests 2 and 4 is different
for the mean and stddev tests. That will always fail.

     Expected mean_and_variance_get_mean(mv) == mean[i], but
        mean_and_variance_get_mean(mv) == 22 (0x16)
        mean[i] == 10 (0xa)

Drop the bad tests.

Fixes: 65bc4109 ("mean and variance: More tests")
Closes: https://lore.kernel.org/lkml/065b94eb-6a24-4248-b7d7-d3212efb4787@roeck-us.net/
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

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

This adds a new watermark, higher priority than BCH_WATERMARK_reclaim,
for interior btree updates. We've seen a deadlock where journal replay
triggers a ton of btree node merges, and these use up all available open
buckets and then interior updates get stuck.

One cause of this is that we're currently lacking btree node merging on
write buffer btrees - that needs to be fixed as well.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

Sign error when checking the watermark - oops.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

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

overlapping extent repair was colliding with extent past end of inode
checks - don't update "extent ends at" until we know we have an extent.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

We were missing an iter_traverse().
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

If something is wrong with a logged op, we just want to delete it -
there's nothing to repair.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

This adds opts.recovery_pass_limit, and redoes -o norecovery to make use
of it; this fixes some issues with -o norecovery so it can be safely
used for data recovery.

Norecovery means "don't do journal replay"; it's an important data
recovery tool when we're getting stuck in journal replay.

When using it this way we need to make sure we don't free journal keys
after startup, so we continue to overlay them: thus it needs to imply
retain_recovery_info, as well as nochanges.

recovery_pass_limit is an explicit option for telling recovery to exit
after a specific recovery pass; this is a much cleaner way of
implementing -o norecovery, as well as being a useful debug feature in
its own right.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

Flag that we need to run a recovery pass and run it - persistenly, so if
we crash it'll still get run.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

This makes bch_sb_field_ext more consistent with the rest of -o
nochanges - we don't want to be varying other codepaths based on -o
nochanges, since it's used for testing in dry run mode; also fixes some
potential null ptr derefs.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

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

Finishing logged ops requires the filesystem to be in a reasonably
consistent state - and other fsck passes don't require it to have
completed, so just run it last.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>