hash_check_key() checks and repairs the hash table btrees: dirents and
xattrs are open addressing hash tables.
We recently had a corruption reported where the hash type on an inode
somehow got flipped, which made the existing dirents invisible and
allowed new ones to be created with the same name.
Now, hash_check_key() can repair duplicates: it will delete one of them,
if it has an xattr or dangling dirent, but if it has two valid dirents
one of them gets renamed.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Different versions of the same inode (same inode number, different
snapshot ID) must have the same hash seed and type - lookups require
this, since they see keys from different snapshots simultaneously.
To repair we only need to make the inodes consistent, hash_check_key()
will do the rest.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Using commit_do() to call alloc_sectors_start_trans() breaks when we're
randomly injecting transaction restarts - the restart in the commit
causes us to leak the lock that alloc_sectorS_start_trans() takes.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
fsck can now correctly check if inodes in interior snapshot nodes are
open/in use.
- Tweak the vfs inode rhashtable so that the subvolume ID isn't hashed,
meaning inums in different subvolumes will hash to the same slot. Note
that this is a hack, and will cause problems if anyone ever has the
same file in many different snapshots open all at the same time.
- Then check if any of those subvolumes is a descendent of the snapshot
ID being checked
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
There's an inherent race in taking a snapshot while an unlinked file is
open, and then reattaching it in the child snapshot.
In the interior snapshot node the file will appear unlinked, as though
it should be deleted - it's not referenced by anything in that snapshot
- but we can't delete it, because the file data is referenced by the
child snapshot.
This was being handled incorrectly with
propagate_key_to_snapshot_leaves() - but that doesn't resolve the
fundamental inconsistency of "this file looks like it should be deleted
according to normal rules, but - ".
To fix this, we need to fix the rule for when an inode is deleted. The
previous rule, ignoring snapshots (there was no well-defined rule
for with snapshots) was:
Unlinked, non open files are deleted, either at recovery time or
during online fsck
The new rule is:
Unlinked, non open files, that do not exist in child snapshots, are
deleted.
To make this work transactionally, we add a new inode flag,
BCH_INODE_has_child_snapshot; it overrides BCH_INODE_unlinked when
considering whether to delete an inode, or put it on the deleted list.
For transactional consistency, clearing it handled by the inode trigger:
when deleting an inode we check if there are parent inodes which can now
have the BCH_INODE_has_child_snapshot flag cleared.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
BCH_INODE_i_size_dirty dates from before we had logged operations for
truncate (as well as finsert) - it hasn't been needed since before
bcachefs was mainlined.
BCH_INODE_i_sectors_dirty hasn't been needed since we started always
updating i_sectors transactionally - it's been unused for even longer.
BCH_INODE_backptr_untrusted also hasn't been used since prior to
mainlining; when unlinking a hardling, we zero out the backpointer
fields if they're for the dirent being removed.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
When we find an unreachable inode, we now reattach it in the oldest
version that needs to be reattached (thus avoiding redundant work
reattaching every single version), and we now fix up inode -> dirent
backpointers in newer versions as needed - or white out the reattaching
dirent in newer versions, if the newer version isn't supposed to be
reattached.
This results in the second verify fsck now passing cleanly after
repairing on a user-provided filesystem image with thousands of
different snapshots.
Reported-by: Christopher Snowhill <chris@kode54.net>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
With inode backpointers, we can write a very simple
check_unreachable_inodes() pass that only looks for non-unlinked inodes
that are missing backpointers, and reattaches them.
This simplifies check_directory_structure() so that it's now only
checking for directory structure loops,
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
It was initially believed that it would be better to be explicit about
the snapshot we're updating when writing inodes in fsck; however, it
turns out that passing around the snapshot separately is more error
prone and we're usually updating the inode in the same snapshow we read
it from.
This is different from normal filesystem paths, where we do the update
in the snapshot of the subvolume we're in.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
We want to check for this early so it can be reattached if necessary in
check_unreachable_inodes(); better than letting it be deleted and having
the children reattached, losing their filenames.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
link count works differently in bcachefs - it's only nonzero for files
with multiple hardlinks, which means we can also avoid checking it
except for files that are known to have hardlinks.
That means we need a few different checks instead; in particular, we
don't want fsck to delet a file that has a dirent pointing to it.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
It's legal for regular files to have missing backpointers (due to
hardlinks), and fsck should automatically add them, but for directories
this is an error that should be flagged.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Ensure a copy of the lost+found inode exists in the snapshot that we're
reattaching, so that we don't trigger warnings in
lookup_inode_for_snapshot() later.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
we're returning an error code now, not a bool
Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
if an inode backpointer points to a dirent that doesn't point back,
that's an error we should warn about.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Add a filesystem flag to indicate whether we did a clean recovery -
using c->sb.clean after we've got rw is incorrect, since c->sb is
updated whenever we write the superblock.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Previously, check_inode() would delete unlinked inodes if they weren't
on the deleted list - this code dating from before there was a deleted
list.
But, if we crash during a logged op (truncate or finsert/fcollapse) of
an unlinked file, logged op resume will get confused if the inode has
already been deleted - instead, just add it to the deleted list if it
needs to be there; delete_dead_inodes runs after logged op resume.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Dealing with outside state within a btree transaction is always tricky.
check_extents() and check_dirents() have to accumulate counters for
i_sectors and i_nlink (for subdirectories). There were two bugs:
- transaction commit may return a restart; therefore we have to commit
before accumulating to those counters
- get_inode_all_snapshots() may return a transaction restart, before
updating w->last_pos; then, on the restart,
check_i_sectors()/check_subdir_count() would see inodes that were not
for w->last_pos
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
fsck_err() jumps to the fsck_err label when bailing out; need to make
sure bp_iter was initialized...
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
If a file is unlinked but still open, we don't want online fsck to
delete it - or fun inconsistencies will happen.
https://github.com/koverstreet/bcachefs/issues/727
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
ret was assigned twice in check_dirent_to_subvol(). Reported by cocci.
Signed-off-by: Yuesong Li <liyuesong@vivo.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
fsck_err() now optionally takes a btree_trans; if the current thread has
one, it is required that it be passed.
The next patch will use this to unlock when waiting for user input.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Consolidate duplicated checks for extents/dirents/xattrs - these keys
should all have a corresponding inode of the correct type.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
fsck.c always runs top of the stack so we're not too concerned here;
noinline_for_stack is sufficient
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
delete_dead_snapshots now runs before the main fsck.c passes which check
for keys for invalid snapshots; thus, it needs those checks as well.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
This function is used for finding the hash seed (which is the same in
all versions of an inode in different snapshots): ff an inode has been
deleted in a child snapshot we need to iterate until we find a live
version.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Originally, when deleting snapshots we didn't collapse redundant
snapshot nodes; thus, the notion of a class of equivalent snapshot nodes
leaked into fsck.
Now we do, so snapshot ID equivalence classes are purely local to
snapshot deletion.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Combine iter/update/trigger/str_hash flags into a single enum, and
x-macroize them for a to_text() function later.
These flags are all for a specific iter/key/update context, so it makes
sense to group them together - iter/update/trigger flags were already
given distinct bits, this cleans up and unifies that handling.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
If an inode is missing, but corresponding extents and dirent still
exist, it's well worth recreating it - this does so.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
overlapping extent repair was colliding with extent past end of inode
checks - don't update "extent ends at" until we know we have an extent.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
We've grown a fair amount of code for managing recovery passes; tracking
which ones we're running, which ones need to be run, and flagging in the
superblock which ones need to be run on the next recovery.
So it's worth splitting out into its own file, this code is pretty
different from the code in recovery.c.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
We only need to return transaction_restart_nested when we're inside a
context that's handling transaction restarts.
Also, add a missing check_subdir_count() call.
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>
