This changes for_each_btree_node() to work like for_each_btree_key(),
and to that end bch2_btree_iter_peek_node() and next_node() also return
error ptrs.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

When a reflink pointer points to an indirect extent that doesn't exist,
we need to replace it with a KEY_TYPE_error key.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

Checking of directory structure across subvolumes was broken - we need
to look up the snapshot ID of the parent subvolume when crossing subvol
boundaries.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

Subvolume deletion doesn't flush & evict the btree key cache - ideally
it would, but that's tricky, so instead bch2_subvolume_create() needs to
make sure the slot doesn't exist in the key cache to avoid triggering
assertions.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

Type size_t is architecture-specific. Fix warnings for some non-amd64
arches.
Signed-off-by: Brett Holman <bholman.devel@gmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

This bug was only discovered when we started using the 2nd word in the
val, which should have been zeroed out as those fields had never been
used before - ouch.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

We were shadowing our exist status, oops
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

Also print the key beyng overwritten for each update.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

This fixes a null ptr deref in bio_alloc_bioset() -> biovec_slab()
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

When force-removing a device, we were silently dropping extents that we
no longer had pointers for - we should have been switching them to
KEY_TYPE_error, so that reads for data that was lost return errors.

This patch adds the logic for switching a key to KEY_TYPE_error to
bch2_bkey_drop_ptr(), and improves the logic somewhat.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

With snapshots, __bch2_dev_usr_data_drop() now uses an ALL_SNAPSHOTS
iterator, which isn't an extent iterator - meaning we shouldn't be
inserting whiteouts with nonzero size to delete. This fixes a bug where
we go RO because we tried to insert an invalid key in the device remove
path.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

Prevent false positives in bch2_varint_decode_fast()
Signed-off-by: Brett Holman <bholman.devel@gmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

It was switching off of the key type incorrectly - this code must've
been quite old, and not rereplicating anything that wasn't a
btree_ptr_v1 or a plain old extent.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

When we delete a snapshot, we unlink the inode but we don't want to run
the inode_rm path - the unlink path deletes the subvolume directly,
which does everything we need. Also allowing the inode_rm path to run
was getting us "missing subvolume" errors.

There's still another bug with snapshot deletion: we need to make
snapshot deletion a multi stage process, where we unlink the root
dentry, then tear down the page cache, then delete the snapshot.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

this_cpu_ptr() emits a warning when used without preemption disabled -
harmless in this case, as we have other locking where
bch2_acc_percpu_u64s() is used.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

bch2_trans_begin() is now required for transaction restarts.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

These paths weren't updated for btree_path and snapshots - a couple of
minor fixes.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

 - check for getting to the end of the btree in bch2_path_verify_locks
   and __btree_path_traverse_all(), this fixes an infinite loop in
   __btree_path_traverse_all().
 - relax requirement in bch2_btree_node_upgrade() that we must want an
   intent lock, this fixes bugs with paths that point to interior nodes
   (nonzero level).
 - bch2_btree_node_update_key(): fix it to upgrade the path to an intent
   lock, if necessary
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

Btree node iterators want the interior btree_path to point to the same
pos as the returned btree node - this fixes a regression from the
introduction of btree_path, where rewriting/updating keys of btree nodes
(e.g. in bch2_dev_metadata_drop()) via btree node iterators.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

It was missing a lockrestart_do(), to call bch2_trans_begin() and also
handle transaction restarts.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

Factor out a little helper.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

We return 1 to indicate kthread_should_stop() returned true - we
shouldn't be printing an error.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

We were getting spurious "multiple types of data in same bucket" errors
in fsck, because the check was running for (cached) stale pointers -
oops.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

We were incorrectly using bch2_inode_write(), which gets the snapshot ID
from the iterator, with a BTREE_ITER_ALL_SNAPSHOTS iterator -
fortunately caught by an assertion in the update path.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

This will cause the compat code to be run that creates entries in the
subvolumes and snapshots btrees.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

We can end up in a strange situation where a btree_path points to a node
being freed even after pointers to it should have been replaced by
pointers to the new node - if the btree node has been reused since the
pointer to it was created.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

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>

Now that all the existing code has been converted for snapshots, this
patch changes the code for initializing a btree iterator to require a
snapshot to be specified, and also change bkey_invalid() to allow for
non U32_MAX snapshot IDs.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

This finishes updating the unit & perf tests for snapshots - btrees that
use snapshots now always require the snapshot field of the start
position to be a valid snapshot ID.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

The data move path operates on existing extents, and not within a
subvolume as the regular IO paths do. It needs to change because it may
cause existing extents to be split, and when splitting an existing
extent in an ancestor snapshot we need to make sure the new split has
the same visibility in child snapshots as the existing extent.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

This patch adds KEY_TYPE_whiteout, a new type of whiteout for snapshots,
when we're deleting and the key being deleted is in an ancestor
snapshot - and updates the transaction update/commit path to use it.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

This plumbs around the subvolume ID as was done previously for other
filesystem code, but now for the IO paths - the control flow in the IO
paths is trickier so the changes in this patch are more involved.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

This updates the fsck algorithms to handle snapshots - meaning there
will be multiple versions of the same key (extents, inodes, dirents,
xattrs) in different snapshots, and we have to carefully consider which
keys are visible in which snapshot.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

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>

For snapshots, we need to implement btree lookups that return the first
key that's an ancestor of the snapshot ID the lookup is being done in -
and filter out keys in unrelated snapshots. This patch adds the btree
iterator flag BTREE_ITER_FILTER_SNAPSHOTS which does that filtering.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

Filesystem operations generally operate within a subvolume: at the start
of every btree transaction we'll be looking up (and locking) the
subvolume to get the current snapshot ID, which we then use for our
other btree lookups in BTREE_ITER_FILTER_SNAPSHOTS mode.

But inodes don't record what subvolume they're in - they can't, because
if they did we'd have to update every single inode within a subvolume
when taking a snapshot in order to keep that field up to date. So it
needs to be tracked in memory, based on how we got to that inode.

Hence this patch adds a subvolume field to ei_inode_info, and switches
to iget5() so we can index by it in the inode hash table.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

On existing filesystems, we have a single global lost+found. Introducing
subvolumes means we need to introduce per subvolume lost+found
directories, because inodes are added to lost+found by their inode
number, and inode numbers are now only unique within a subvolume.

This patch adds support to fsck for per subvolume lost+found.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

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>

This patch adds subvolume.c - support for the subvolumes and snapshots
btrees and related data types and on disk data structures. The next
patches will start hooking up this new code to existing code.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

Existing quota support breaks badly with snapshots. We're not deleting
the code because some of it will be needed when we reimplement quotas
along the lines of btrfs subvolume quotas.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>