This patch converts more enums in the on disk format to our standard
x-macro-with-strings deal - to enable better pretty-printing.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

In bcachefs, inodes and dentries are also cached - more compactly - by
the btree node cache, they don't require seeks to recreate.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

bch2_dirent_lookup had an error path where we'd exit a btree_iter that
hadn't been properly initialized.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

When attempting to free btree nodes, we might not be able to free all
the nodes that were requested. But the code was looping until it had
freed _all_ the nodes requested, when it should have only been
attempting to free nr nodes.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

If at all possible we'd prefer to not fail page writeback unless the
filesystem has been shutdown; allowing errors in page writeback means
things we'd like to assert about i_size consistency between the VFS and
the btree go out the window.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

This fixes a bug where i_size may become inconsistent between the VFS
cache and the btree, when the filesystem is nearly full.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

- fpunch wasn't always correctly updating i_size - when we drop buffered
  writes that were extending a file, we become responsible for writing
  i_size.

- fzero was sometimes zeroing out more data that it should have -
  block_start and block_end were being rounded in the wrong directions
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

This cleans up the error hanlding and flow control a bit.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

This adds a new assertion to be used by bch2_inode_update_after_write(),
which updates the VFS inode based on the update to the btree inode we
just did - we require that the btree inode still be locked when we do
that update.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

 - We should only be clearing should_be_locked in btree_path_set_pos() -
   it's the responsiblity of the btree_path code, not the btree_iter
   code.

 - bch2_path_put() needs to pay attention to path->should_be_locked, to
   ensure we don't drop locks we're supposed to be keeping.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

It used to be that error reporting in the startup path was done by
returning strings describing the error, but that turned out to be a
rather silly idea - if there's something we can describe about the
error, just print it right away.

This converts a good chunk of code to returning error codes, as is more
typical style.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

bch2_fs_encryption_init() correctly passes back -ENOKEY from request_key()
when no unlock key is found, or -EINVAL if superblock decryption fails
because of an invalid key. However, these get absorbed into a generic NULL
return from bch2_fs_alloc() and later returned to user space as -ENOMEM,
leading to a misleading error from mount(1):

  mount(2) system call failed: Out of memory.

Return explicit error pointers out of bch2_fs_alloc() and handle them in
both callers, so the user instead sees

  mount(2) system call failed: Required key not available.

when attempting to mount a filesystem which is still locked.
Signed-off-by: Chris Webb <chris@arachsys.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

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

Now that we're recording in each inode the journal sequence number of
the most recent update, fsync becomes a lot simpler and we can delete
all the plumbing for ei_journal_seq.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

We're getting rid of code that uses the in memory bucket array - and we
now have better mechanisms for viewing most of what the bucket quantiles
code gave us (especially internal fragmentation).
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

This was used for recording which inodes have been modified by in flight
journal writes, but was broken and has been superceded.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

Add fields to inode & alloc keys that record the journal sequence number
when they were most recently modified.

For alloc keys, this is needed to know what journal sequence number we
have to flush before the bucket can be reused. Currently this is tracked
in memory, but we'll be getting rid of the in memory bucket array.

For inodes, this is needed for fsync when the inode has been evicted
from the vfs cache. Currently we use a bloom filter per outstanding
journal buf - but that mechanism has been broken since we added the
ability to not issue a flush/fua for every journal write.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

This is going to be a performance regression until we get the btree key
cache re-enabled - but it's needed for fixing fsync. Upcoming patches
will record the journal_seq an inode was updated at in the inode itself.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

We're going to have btree updates that don't need to be journalled; add
a flag for that.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

__lookup_inode() doesn't work for what __remove_dirent() wants - it just
wants the first inode at a given inode number, they all have the same
hash info.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

We were starting at the wrong btree position, and thus not actually
checking any inodes - oops.

Also, make check_key_has_snapshot() a mustfix fsck error, since later
fsck code assumes that all keys have valid snapshot IDs.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

It's helpful to know what the superblock write is for.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

On failure to get a write lock (because we had a conflicting read lock),
we need to make sure to upgrade the read lock to an intent lock - or we
could end up spinning.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

The bch2_btree_path_upgrade() call was failing and tripping an assert -
path->level + 1 is in this case not necessarily exactly what we want,
fix it by upgrading exactly the locks we want.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

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

This allows triggers to distinguish between a key entering the btree -
i.e. being called from the trans commit path - vs. being called on a key
that already exists, i.e. by GC.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

This helps to unify the interface between bch2_mark_key() and
bch2_trans_mark_key() - and it also gives access to the journal
reservation and journal seq in the mark_key path.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

- The backpointer that ec_stripe_update_ptrs() uses now needs to include
  the snapshot ID, which means we have to change where we add the
  backpointer to after getting the snapshot ID for the new extents

- ec_stripe_update_ptrs() needs to be calling bch2_trans_begin()

- improve error message in bch2_mark_stripe()
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

When the old or new key doesn't exist, we should still pass in a deleted
key with the correct pos. This fixes a bug in the ec code, when
bch2_mark_stripe() was looking up the wrong in-memory stripe.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

This tweaks the journal code to always act as if there's space available
in nochanges mode, when we're not going to be doing any writes. This
helps in recovering filesystems that won't mount because they need
journal replay and the journal has gotten stuck.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

The fsck code has been handling transaction restarts locally, to avoid
calling fsck_err() multiple times (and asking the user/logging the error
multiple times) on transaction restart.

However, with our improving assertions about iterator validity, this
isn't working anymore - the code wasn't entirely correct, in ways that
are fine for now but are going to matter once we start wanting online
fsck.

This code converts much of the fsck code to handle transaction restarts
in a more rigorously correct way - moving restart handling up to the top
level of check_dirent, check_xattr and others - at the cost of logging
errors multiple times on transaction restart.

Fixing the issues with logging errors multiple times is probably going
to require memoizing calls to fsck_err() - we'll leave that for future
improvements.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

Was popping an assertion on !BTREE_ITER_ALL_SNAPSHOTS iters when getting
to the end.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

This fixes building in userspace - code that's coupled to the kernel VFS
interface should live in fs.c
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

nochanges mode is often used for getting data off of otherwise
nonrecoverable filesystems, which is often because of errors hit during
fsck.

Don't force version upgrade & fsck in nochanges mode, so that it's more
likely to mount.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

Back when we relied on the journal sequence number blacklist machinery
for consistency between btree and the journal, we needed to ensure a new
journal entry was written before any btree writes were done. But, this
had the side effect of consuming some space in the journal prior to
doing journal replay - which could lead to a very wedged filesystem,
since we don't yet have a way to grow the journal prior to going RW.

Fortunately, the journal sequence number blacklist machinery isn't
needed anymore, as btree node pointers now record the numer of sectors
currently written to that node - that code should all be ripped out.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

Snapshot deletion needs to become a multi step process, where we unlink,
then tear down the page cache, then delete the subvolume - the deleting
flag is equivalent to an inode with i_nlink = 0.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

We should always print out the key we were marking.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

It seems some users have reflink pointers which span many indirect
extents, from a short window in time when merging of reflink pointers
was allowed.

Now, we're seeing transaction path overflows in fix_reflink_p(), the
code path to clear out the reflink_p fields now used for front/back pad
- but, we don't actually need to be running triggers in that path, which
is an easy partial fix.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

for_each_btree_key() now calls bch2_trans_begin() as needed; that means,
we can also call it when we're in danger of overflowing transaction
paths.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

The way __bch2_mark_reflink_p returns errors was clashing with returning
the number of sectors processed - we weren't returning FSCK_ERR_EXIT
correctly.

Fix this by only using the return code for errors, which actually ends
up simplifying the overall logic.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>