Avoid the private error code return to caller. The error code
should be transformed into genernal error code.
Signed-off-by: Hongbo Li <lihongbo22@huawei.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

Non append, non extending buffered writes can now avoid taking the inode
lock.

To ensure atomicity of writes w.r.t. other writes, we lock every folio
that we'll be writing to, and if this fails we fall back to taking the
inode lock.

Extensive comments are provided as to corner cases.

Link: https://lore.kernel.org/linux-fsdevel/Zdkxfspq3urnrM6I@bombadil.infradead.org/Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

Rename and export __file_remove_privs(); for a buffered write path that
doesn't take the inode lock we need to be able to check if the operation
needs to do work first.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Christian Brauner <brauner@kernel.org>

Improved journal pipelining broke journal_noflush_seq(); it implicitly
assumed only the oldest outstanding journal buf could be in flight, but
that's no longer true.

Make this more straightforward by just setting buf->must_flush whenever
we know a journal buf is going to be flush.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

When mount with incorrect options such as:
"mount -t bcachefs -o errors=back /dev/loop1 /mnt/bcachefs/".
It rebacks the error "mount: /mnt/bcachefs: permission denied."
 cause bch2_parse_mount_opts returns -1 and bch2_mount throws
it up. This is unreasonable.

The real error message should be like this:
"mount: /mnt/bcachefs: wrong fs type, bad option, bad
superblock on /dev/loop1, missing codepage or helper program,
or other error."

Adding three private error codes for mounting error. Here are:
  - BCH_ERR_mount_option as the parent class for option error.
  - BCH_ERR_option_name represents the invalid option name.
  - BCH_ERR_option_value represents the invalid option value.
Signed-off-by: Hongbo Li <lihongbo22@huawei.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

prep work for replaying the journal backwards
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

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

nice bit of code cleanup
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

This will let us use some darray helpers in the next patch.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

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

Add a tracepoint for downcasting private errors to standard errors, so
they can be recovered even when not logged; also, add some
documentation.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

Variable ret is being assigned a value that is never read, it is
being re-assigned a couple of statements later on. The assignment
is redundant and can be removed.

Cleans up clang scan build warning:
fs/bcachefs/super-io.c:806:2: warning: Value stored to 'ret' is
never read [deadcode.DeadStores]
Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

32-bit arm builds emit a lot of spam like this:

    fs/bcachefs/backpointers.c: In function ‘extent_matches_bp’:
    fs/bcachefs/backpointers.c:15:13: note: parameter passing for argument of type ‘struct bch_backpointer’ changed in GCC 9.1

Apply the change from commit ebcc5928 ("arm64: Silence gcc warnings
about arch ABI drift") to fs/bcachefs/ to silence them.
Signed-off-by: Calvin Owens <jcalvinowens@gmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

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

All jounal_buf bitfield updates must happen under the journal lock -
perhaps we should just switch these to atomic bit flags.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

Buckets usually can't be discarded until the transaction that made them
empty has been committed in the journal.

Tracing has indicated that we're queuing the discard worker excessively,
only for it to skip over many buckets that are still waiting on a
journal commit, discarding only one or two buckets per iteration.

We want to switch to only queuing the discard worker after a journal
flush write, but there's an important optimization we need to preserve:
if a bucket becomes empty and it was never committed in the journal
while it was in use, we want to discard it and reuse it right away -
since overwriting it before the previous writes are flushed from the
device cache eans those writes only cost bus bandwidth.

So, this patch implements a fast path for buckets that can be discarded
right away. We need new locking between the two discard workers; the new
list of buckets being discarded provides that locking.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

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

If a path doesn't have any active references, we shouldn't downgrade it;
it'll either be reused, possibly with intent refs again, or dropped at
bch2_trans_begin() time.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

Signed-off-by: Daniel Hill <daniel@gluo.nz>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

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

Now that checking subvolume structure is a separate pass, the main
check_directory_connectivity() pass only needs to walk up to a given
inode's subvolume root.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

Now that we've got bch_subvolume.fs_path_parent, it's easy to write
subvolume
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

This is needed for building Rust bindings on big endian architectures
like s390x. Currently this is only done in userspace, but it might
happen in-kernel in the future. When creating a Rust binding for struct
bkey, the "packed" attribute is needed to get a type with the correct
member offsets in the big endian case. However, rustc does not allow
types to have both a "packed" and "align" attribute. Thus, in order to
get a Rust type compatible with the C type, we must omit the "aligned"
attribute in C.

This does not affect the struct's size or member offsets, only its
toplevel alignment, which should be an acceptable impact.

The little endian version can have the "align" attribute because the
"packed" attr is redundant, and rust-bindgen will omit the "packed" attr
when an "align" attr is present and it can do so without changing a
type's layout
Signed-off-by: Thomas Bertschinger <tahbertschinger@gmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

bch2_trigger_alloc() kicks off certain tasks on bucket state changes;
e.g. triggering the bucket discard worker and the invalidate worker.

We've observed the discard worker running too often - most runs it
doesn't do any work, according to the tracepoint - so clearly, we're
kicking it off too often.

This adds an explicit statechange() macro to make these checks more
precise.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

Make sure early error messages get redirected, for
kernel-fsck-from-userland.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

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

THis silences a mm/page_alloc.c warning about allocating more than a
page with GFP_NOFAIL - and there's no reason for this to not have a
vmalloc fallback anyways.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

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

When bch2_btree_iter_peek_slot() clones the iterator to search for the
next key, and then discovers that the key from the cloned iterator is
the key we want to return - we also want to save the
iter->key_cache_path as well, for the update path.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

Various phases of fsck involve checking references from one btree to
another: this means doing a sequential scan of one btree, and then
mostly random access into the second.

This is particularly painful for checking extents <-> backpointers; we
can prefetch btree node access on the sequential scan, but not on the
random access portion, and this is particularly painful on spinning
rust, where we'd like to keep the pipeline fairly full of btree node
reads so that the elevator can reduce seeking.

This patch implements prefetching and pinning of the portion of the
btree that we'll be doing random access to. We already calculate how
much of the random access btree will fit in memory so it's a fairly
straightforward change.

This will put more pressure on system memory usage, so we introduce a
new option, fsck_memory_usage_percent, which is the percentage of total
system ram that fsck is allowed to pin.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

Recursively destroying subvolumes isn't allowed yet.

Fixes: https://github.com/koverstreet/bcachefs/issues/634Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

Add a btree to record a parent -> child subvolume relationships,
according to the filesystem heirarchy.

The subvolume_children btree is a bitset btree: if a bit is set at pos
p, that means p.offset is a child of subvolume p.inode.

This will be used for efficiently listing subvolumes, as well as
recursive deletion.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

Record the filesystem path heirarchy for subvolumes in bch_subvolume
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

Provide a non-write buffer version of bch2_btree_bit_mod_buffered(), for
the subvolume children btree.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

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

Subvolumes need special handling to reattach - we always reattach them
in the root subvolume's lost+found, and they need a slightly different
kind of dirent.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

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

prep work for improving logging/error messages
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

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

bit of renaming, prep for adding a fs path parent
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>