bcachefs: Correctly reattach subvolumes

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>

bcachefs: Cleanup bch2_dirent_lookup_trans()

Drop an unnecessary bch2_subvolume_get_snapshot() call, and drop the __
from the name - this is a normal interface.

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

bcachefs: skip invisible entries in empty subvolume checking

When we are checking whether a subvolume is empty in the specified snapshot,
entries that do not belong to this subvolume should be skipped.

This fixes the following case:

$ bcachefs subvolume create ./sub
$ cd sub
$ bcachefs subvolume create ./sub2
$ bcachefs subvolume snapshot . ./snap
$ ls -a snap
. ..
$ rmdir snap
rmdir: failed to remove 'snap': Directory not empty

As Kent suggested, we pass 0 in may_delete_deleted_inode() to ignore subvols
in the subvol we are checking, because inode.bi_subvol is only set on
subvolume roots, and we can't go through every inode in the subvolume and
change bi_subvol when taking a snapshot. It makes the check less strict, but
that's ok, the rest of fsck will still catch it.

Signed-off-by: Guoyu Ou <benogy@gmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

bcachefs: Fix reattach_inode() for snapshots

reattach_inode() was broken w.r.t. snapshots - we'd lookup the subvolume
to look up lost+found, but if we're in an interior node snapshot that
didn't make any sense.

Instead, this adds a dirent path for creating in a specific snapshot,
skipping the subvolume; and we also make sure to create lost+found in
the root snapshot, to avoid conflicts with lost+found being created in
overlapping snapshots.

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

bcachefs: bch_str_hash_flags_t

Create a separate enum for str_hash flags - instead of abusing the
btree_insert_flags enum - and create a __bitwise typedef for sparse
typechecking.

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

bcachefs: Fix deleted inode check for dirs

We could delete directories transactionally on rmdir()/unlink(), but we
don't; instead, like with regular files we wait for the VFS to call
evict().

That means that our check for directories in the deleted inodes btree is
wrong - the check should be for non-empty directories.

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

bcachefs: Enumerate fsck errors

This patch adds a superblock error counter for every distinct fsck
error; this means that when analyzing filesystems out in the wild we'll
be able to see what sorts of inconsistencies are being found and repair,
and hence what bugs to look for.

Errors validating bkeys are not yet considered distinct fsck errors, but
this patch adds a new helper, bkey_fsck_err(), in order to add distinct
error types for them as well.

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

bcachefs: Introduce bch2_dirent_get_name

A nice cleanup that avoids a bunch of open-coding name/string usage
around dirent usage.

Will be used by casefolding impl in future commits.

Signed-off-by: Joshua Ashton <joshua@froggi.es>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

bcachefs: Change check for invalid key types

As part of the forward compatibility patch series, we need to allow for
new key types without complaining loudly when running an old version.

This patch changes the flags parameter of bkey_invalid to an enum, and
adds a new flag to indicate we're being called from the transaction
commit path.

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

bcachefs: bkey_ops.min_val_size

This adds a new field to bkey_ops for the minimum size of the value,
which standardizes that check and also enforces the new rule (previously
done somewhat ad-hoc) that we can extend value types by adding new
fields on to the end.

To make that work we do _not_ initialize min_val_size with sizeof,
instead we initialize it to the size of the first version of those
values.

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

bcachefs: Change bkey_invalid() rw param to flags

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

bcachefs: More style fixes

Fixes for various checkpatch errors.

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

bcachefs: Add rw to .key_invalid()

This adds a new parameter to .key_invalid() methods for whether the key
is being read or written; the idea being that methods can do more
aggressive checks when a key is newly created and being written, when we
wouldn't want to delete the key because of those checks.

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

bcachefs: Convert .key_invalid methods to printbufs

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

bcachefs: Update export_operations for snapshots

When support for snapshots was merged, export operations weren't
updated yet. This patch adds new filehandle types for bcachefs that
include the subvolume ID and updates export operations for subvolumes -
and also .get_parent, support for which was added just prior to
snapshots.

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

bcachefs: Subvol dirents are now only visible in parent subvol

This changes the on disk format for dirents that point to subvols so
that they also record the subvolid of the parent subvol, so that we can
filter them out in other subvolumes.

This also updates the dirent code to do that filtering, and in
particular tweaks the rename code - we need to ensure that there's only
ever one dirent (counting multiplicities in different snapshots) that
point to a subvolume.

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

bcachefs: Snapshot creation, deletion

This is the final patch in the patch series implementing snapshots.
This patch implements two new ioctls that work like creation and
deletion of directories, but fancier.

- BCH_IOCTL_SUBVOLUME_CREATE, for creating new subvolumes and snaphots
- BCH_IOCTL_SUBVOLUME_DESTROY, for deleting subvolumes and snapshots

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

bcachefs: Plumb through subvolume id

To implement snapshots, we need every filesystem btree operation (every
btree operation without a subvolume) to start by looking up the
subvolume and getting the current snapshot ID, with
bch2_subvolume_get_snapshot() - then, that snapshot ID is used for doing
btree lookups in BTREE_ITER_FILTER_SNAPSHOTS mode.

This patch adds those bch2_subvolume_get_snapshot() calls, and also
switches to passing around a subvol_inum instead of just an inode
number.

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

bcachefs: Add support for dirents that point to subvolumes

Dirents currently always point to inodes. Subvolumes add a new type of
dirent, with d_type DT_SUBVOL, that instead points to an entry in the
subvolumes btree, and the subvolume has a pointer to the root inode.

This patch adds bch2_dirent_read_target() to get the inode (and
potentially subvolume) a dirent points to, and changes existing code to
use that instead of reading from d_inum directly.

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

bcachefs: btree_path

This splits btree_iter into two components: btree_iter is now the
externally visible componont, and it points to a btree_path which is now
reference counted.

This means we no longer have to clone iterators up front if they might
be mutated - btree_path can be shared by multiple iterators, and cloned
if an iterator would mutate a shared btree_path. This will help us use
iterators more efficiently, as well as slimming down the main long lived
state in btree_trans, and significantly cleans up the logic for iterator
lifetimes.

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

bcachefs: Inode backpointers

This patch adds two new inode fields, bi_dir and bi_dir_offset, that
point back to the inode's dirent.

Since we're only adding fields for a single backpointer, files that have
been hardlinked won't necessarily have valid backpointers: we also add a
new inode flag, BCH_INODE_BACKPTR_UNTRUSTED, that's set if an inode has
ever had multiple links to it. That's ok, because we only really need
this functionality for directories, which can never have multiple
hardlinks - when we add subvolumes, we'll need a way to enemurate and
print subvolumes, and this will let us reconstruct a path to a subvolume
root given a subvolume root inode.

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

bcachefs: Convert all bch2_trans_commit() users to BTREE_INSERT_ATOMIC

BTREE_INSERT_ATOMIC should really be the default mode, and there's not
that much code that doesn't need it - so this is prep work for getting
rid of the flag.

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

bcachefs: Can't be holding read locks while taking write locks

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

bcachefs: Factor out fs-common.c

This refactoring makes the code easier to understand by separating the
bcachefs btree transactional code from the linux VFS code - but more
importantly, it's also to share code with the fuse port.

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

bcachefs: Fsck locking improvements

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

bcachefs: Make bkey types globally unique

this lets us get rid of a lot of extra switch statements - in a lot of
places we dispatch on the btree node type, and then the key type, so
this is a nice cleanup across a lot of code.

Also improve the on disk format versioning stuff.

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

bcachefs: revamp to_text methods

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

bcachefs: Dirent repair code

There was a bug for awhile in previous kernels where we weren't
computing dirent name lengths correctly and we weren't zeroing out
padding at the end of dirents (due to struct bch_dirent changing size by
adding __attribute__((aligned)), and not updating other code to use
offsetof).

This patch fixes dirents with junk at the end, by going off of the
dirent's hash.

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

bcachefs: fix bch2_val_to_text()

was returning wrong value

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

bcachefs: Initial commit

Initially forked from drivers/md/bcache, bcachefs is a new copy-on-write
filesystem with every feature you could possibly want.

Website: https://bcachefs.org

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