Add an option for completely disabling casefolding on a filesystem, as a
workaround for overlayfs.
This should only be needed as a temporary workaround, until the
overlayfs fix arrives.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Don't mark btree nodes for rewrites, if they are or would be degraded,
if journal replay hasn't finished, to avoid a deadlock.
This is because btree node rewrites generate more updates for the
interior updates (alloc, backpointers), and if those updates touch
new nodes and generate more rewrites - we can only have so many interior
btree updates in flight before we deadlock on open_buckets.
The biggest cause is that we don't use the btree write buffer (for
the backpointer updates - this needs some real thought on locking in
order to fix.
The problem with this workaround (not doing the rewrite for degraded
nodes in journal replay) is that those degraded nodes persist, and we
don't want that (this is a real bug when a btree node write completes
with fewer replicas than we wanted and leaves a degraded node due to
device _removal_, i.e. the device went away mid write).
It's less of a bug here, but still a problem because we don't yet
have a way of tracking degraded data - we another index (all
extents/btree nodes, by replicas entry) in order to fix properly
(re-replicate degraded data at the earliest possible time).
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Fix a 6.16 regression from the recovery pass rework, which introduced a
bug where calling bch2_run_explicit_recovery_pass() would only return
the error code to rewind recovery for the first call that scheduled that
recovery pass.
If the error code from the first call was swallowed (because it was
called by an asynchronous codepath), subsequent calls would go "ok, this
pass is already marked as needing to run" and return 0.
Fixing this ensures that check_topology bails out to run btree_node_scan
before doing any repair.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Previously, calling bch2_btree_has_scanned_nodes() when btree node
scan hadn't actually run would erroniously return false - causing us to
think a btree was entirely gone.
This fixes a 6.16 regression from moving the scheduling of btree node
scan out of bch2_btree_lost_data() (fixing the bug where we'd schedule
it persistently in the superblock) and only scheduling it when
check_toploogy() is asking for scanned btree nodes.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Before calling bch2_indirect_extent_missing_error(), we have to
calculate the missing range, which is the intersection of the reflink
pointer and the non-indirect-extent we found.
The calculation didn't take into account that the returned extent may
span the iter position, leading to an infinite loop when we
(unnecessarily) resized the extent we were returning to one that didn't
extend past the offset we were looking up.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
This fixes exceeding the bump allocator limit when the allocator finds
many buckets that need repair - they're repaired asynchronously, which
means that every error logged a message in the bump allocator, without
committing.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Don't change buf->size on error - this would usually be a transaction
restart, but it could also be -ENOMEM - when we've exceeded the bump
allocator max).
Fixes: 247abee6ae ("bcachefs: btree_trans_subbuf")
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
The normal fsck code doesn't call key_visible_in_snapshot() with an
empty list of snapshot IDs seen (the current snapshot ID will always be
on the list), but str_hash_repair_key() ->
bch2_get_snapshot_overwrites() can, and that's totally fine as long as
we check for it.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
check_directory_structure runs after check_dirents, so it expects that
it won't see any inodes with missing backpointers - normally.
But online fsck can't run check_dirents yet, or the user might only be
running a specific pass, so we need to be careful that this isn't an
error. If an inode is unreachable, that's handled by a separate pass.
Also, add a new 'bch2_inode_has_backpointer()' helper, since we were
doing this inconsistently.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
btree node scrub was sometimes failing to rewrite nodes with errors;
bch2_btree_node_rewrite() can return a transaction restart and we
weren't checking - the lockrestart_do() needs to wrap the entire
operation.
And there's a better helper it should've been using,
bch2_btree_node_rewrite_key(), which makes all this more convenient.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
We can only pass negative error codes to bch2_err_str(); if it's a
positive integer it's not an error and we trip an assert.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
A path exists in a particular snapshot: we should do the pathwalk in the
snapshot ID of the inode we started from, _not_ change snapshot ID as we
walk inodes and dirents.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
When we find a directory connectivity problem, we should do the repair
in the oldest snapshot that has the issue - so that we don't end up
duplicating work or making a real mess of things.
Oldest snapshot IDs have the highest integer value, so - just walk
inodes in reverse order.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
bch_subvolume.fs_path_parent needs to be updated as well, it should
match inode.bi_parent_subvol.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
The bch2_subvolume_get_snapshot() call needs to happen before the dirent
lookup - the dirent is in the parent subvolume.
Also, check for loops.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
kthread creation checks for pending signals, which is _very_ annoying if
we have to do a long recovery and don't go rw until we've done
significant work.
Check if we'll be going rw and pre-allocate kthreads/workqueues.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Print out more info when we find a key (extent, dirent, xattr) for a
missing inode - was there a good inode in an older snapshot, full(ish)
list of keys for that missing inode, so we can make better decisions on
how to repair.
If it looks like it should've been deleted, autofix it. If we ever hit
the non-autofix cases, we'll want to write more repair code (possibly
reconstituting the inode).
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
After cd3cdb1ef7 ("Single err message for btree node reads"),
all errors caused __btree_err to return -BCH_ERR_fsck_fix no matter what
the actual error type was if the recovery pass was scanning for btree
nodes. This lead to the code continuing despite things like bad node
formats when they earlier would have caused a jump to fsck_err, because
btree_err only jumps when the return from __btree_err does not match
fsck_fix. Ultimately this lead to undefined behavior by attempting to
unpack a key based on an invalid format.
Make only errors of type -BCH_ERR_btree_node_read_err_fixable cause
__btree_err to return -BCH_ERR_fsck_fix when scanning for btree nodes.
Reported-by: syzbot+cfd994b9cdf00446fd54@syzkaller.appspotmail.com
Fixes: cd3cdb1ef7 ("bcachefs: Single err message for btree node reads")
Signed-off-by: Bharadwaj Raju <bharadwaj.raju777@gmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Add a mount option for rewinding the journal, bringing the entire
filesystem to where it was at a previous point in time.
This is for extreme disaster recovery scenarios - it's not intended as
an undelete operation.
The option takes a journal sequence number; the desired sequence number
can be determined with 'bcachefs list_journal'
Caveats:
- The 'journal_transaction_names' option must have been enabled (it's on
by default). The option controls emitting of extra debug info in the
journal, so we can see what individual transactions were doing;
It also enables journalling of keys being overwritten, which is what
we rely on here.
- A full fsck run will be automatically triggered since alloc info will
be inconsistent. Only leaf node updates to non-alloc btrees are
rewound, since rewinding interior btree updates isn't possible or
desirable.
- We can't do anything about data that was deleted and overwritten.
Lots of metadata updates after the point in time we're rewinding to
shouldn't cause a problem, since we segragate data and metadata
allocations (this is in order to make repair by btree node scan
practical on larger filesystems; there's a small 64-bit per device
bitmap in the superblock of device ranges with btree nodes, and we try
to keep this small).
However, having discards enabled will cause problems, since buckets
are discarded as soon as they become empty (this is why we don't
implement fstrim: we don't need it).
Hopefully, this feature will be a one-off thing that's never used
again: this was implemented for recovering from the "vfs i_nlink 0 ->
subvol deletion" bug, and that bug was unusually disastrous and
additional safeguards have since been implemented.
But if it does turn out that we need this more in the future, I'll
have to implement an option so that empty buckets aren't discarded
immediately - lagging by perhaps 1% of device capacity.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Fix the case where we're deleting in a different snapshot and need to
emit a whiteout - that requires a regular BTREE_ITER_filter_snapshots
iterator.
Also, only delete the part of the extent that extents past i_size.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
When the inode was a whiteout, we were inserting a new whiteout at the
wrong (old) snapshot.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Prep work for journal rewind, where the seq we're replaying from may be
different than the last journal entry's last_seq.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Previously, we weren't checking the result of the skiplist walk, just
the is_ancestor bitmap.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
We need to start searching from search_key - _not_ path->pos, which will
point to the key we found in the btree
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
this code is rarely invoked, so - we had a few bugs left from basing it
off of bch2_journal_keys_peek_max()...
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
