For now we only have one key type in these btrees, but forward
compatibility means we do have to check.
Reported-by: syzbot+b4cb4a6988aced0cec4b@syzkaller.appspotmail.com
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>
Snapshot deletion v2 added sentinal values for deleted snapshots, so
"key for deleted snapshot" - i.e. snapshot deletion missed something -
is safe to repair automatically.
But if we find a key for a missing snapshot we have no idea what
happened, and we shouldn't delete it unless we're very sure that
everything else is consistent.
So hook it up to the new bch2_require_recovery_pass(), we'll now only
delete if snapshots and subvolumes have recenlty been checked.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Add a superblock flag to temporarily disable ratelimiting for a recovery
pass.
This will be used to make check_key_has_snapshot safer: we don't want to
delete a key for a missing snapshot unless we know that the snapshots
and subvolumes btrees are consistent, i.e. check_snapshots and
check_subvols have run recently.
Changing those btrees - creating/deleting a subvolume or snapshot - will
set the "disable ratelimit" flag, i.e. ensuring that those passes run if
check_key_has_snapshot discovers an error.
We're only disabling ratelimiting in the snapshot/subvol delete paths,
we're not so concerned about the create paths.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
The new guard(), scoped_guard() allow for more natural code.
Some of the uses with creative flow control have been left.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Add a better helper for printing out paths of inodes when we don't know
the subvolume, for fsck.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
We want recovery.curr_pass to be private to the recovery passes code,
for better showing recovery pass status; also, it may rewind and is
generally not the correct member to use.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Add 'opts.snapshot_deletion_enabled', enabled by default.
This may be turned off so that the new sysfs knob,
'internal/trigger_delete_dead_snapshots', may be used instead - this
will allow snapshot deletion to be profiled more easily.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Since extents, dirents and xattrs require an inode with the
corresponding snapshot ID to exists, we can avoid a lot of scanning by
only scanning those trees for keys to process if the correspending inode
exists.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
We're going to be speeding up snapshot deletion, by only having it
process the extents/dirents/xattrs btrees if an inode of a given
snapshot ID was present.
This raises the possibility of 'bkey_in_missing_snapshot' errors popping
up, if we ever accidentally don't do the corresponding inode update, or
if the new algorithm has bugs.
So instead of deleting snapshot IDs, add a new deleted flag, so that
'key in missing snapshot' errors can more definitively tell what
happened and automatically repair.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
We're going to be speeding up snapshot deletion, by only having it
process the extents/dirents/xattrs btrees if an inode of a given
snapshot ID was present.
This raises the possibility of 'bkey_in_missing_snapshot' errors popping
up, if we ever accidentally don't do the corresponding inode update, or
if the new algorithm has bugs.
So we'll want to be able to differentiate more definitively between
'snapshot went missing' (and perhaps needs to be reconstructed), and
'key in snapshot that was deleted'.
So instead of deleting snapshot IDs, we'll be adding a new deleted flag
and leaving them permanently.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Don't scan keys in inodes for which the snapshot tree doesn't match any
we're deleting from.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Add a better helper for check_snapshot_exists().
create_snapids() can't be changed to use this, unfortunately, because
the transaction that creates new snapshot will also be inserting other
keys (e.g. root inode) that reference that snapshot ID, and they expect
the snapshot table to already be updated.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Codepaths that create entries in the snapshots btree currently call
bch2_mark_snapshot(), which updates the in-memory snapshot table, before
transaction commit.
This is because bch2_mark_snapshot() is an atomic trigger, run with
btree write locks held, and isn't allowed to fail - but it might need to
reallocate the table, hence we call it early when we're still allowed to
fail.
This is generally harmless - if we fail, we'll have left an entry in the
snapshots table around, but nothing will reference it and it'll get
overwritten if reused by another transaction.
But check_snapshot_exists(), which reconstructs snapshots when the
snapshots btree has been corrupted or lost, was erronously rechecking if
the snapshot exists inside the transaction commit loop - so on
transaction restart (in this case mem_realloced), the second iteration
would return without repairing.
This code needs some cleanup: splitting out a "maybe realloc snapshots
table" helper would have avoided this, that will be in the next patch.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
This was planned to be done ages ago, now finally completed; there are
places where we have quite a few btree_trans objects on the stack, so
this reduces stack usage somewhat.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Add the new helper printbuf_indent_add_nextline(), and use it in
__bch2_fsck_err() to centralize setting the indentation of multiline
fsck errors.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
We want all error messages converted to print paths, not just inode
numbers - users want this information, and it speeds up debugging too.
Auditing and converting all error messages is going to be a big project,
so for the moment we're just doing this incrementally.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
When ancestor is less than IS_ANCESTOR_BITMAP, we would get an incorrect
result.
Signed-off-by: Alan Huang <mmpgouride@gmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Ensure that snapshot_tree.master_subvol is cleared when we delete the
master subvolume in a tree of snapshots, and allow for snapshot trees
that don't have a master subvolume in fsck.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Switch to generating a private list of interior nodes to delete, instead
of using the equivalence class in the global data structure.
This eliminates possible races with snapshot creation, and is much
cleaner - it'll let us delete a lot of janky code for calculating and
maintaining the equivalence classes.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
When deleting dead snapshots, we move keys from redundant interior
snapshot nodes to child nodes - unless there's already a key, in which
case the ancestor key is deleted.
Previously, we tracked via equiv_seen whether the child snapshot had a
key, but this was tricky w.r.t. transaction restarts, and not
transactionally safe w.r.t. updates in the child snapshot.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
bch2_snapshot_equiv() is going away; convert users that just wanted to
know if the snapshot exists to something better
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Add a new parameter to bkey validate functions, and use it to improve
invalid bkey error messages: we can now print the btree and depth it
came from, or if it came from the journal, or is a btree root.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
We unconditionally go read-write, if we're going to do so, before
journal replay: lazy_rw is obsolete.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Check if we have snapshot_trees or subvolumes that refer to the snapshot
node being reconstructed, and use them.
With this, the kill_btree_root test that blows away the snapshots btree
now passes, and we're able to successfully reconstruct.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
As we iterate we need to mark that we no longer need iterators -
otherwise we'll infinite loop via the "too many iters" check when
there's many snapshots.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Syzbot reports a problem that a warning is triggered due to suspicious
use of rcu_dereference_check(). That is triggered by a call of
bch2_snapshot_tree_oldest_subvol().
The cause of the warning is that inside
bch2_snapshot_tree_oldest_subvol(), snapshot_t() is called which calls
rcu_dereference() that requires a read lock to be held. Also, the call
of bch2_snapshot_tree_next() eventually calls snapshot_t().
To fix this, call rcu_read_lock() before calling snapshot_t(). Then,
release the lock after the termination of the while loop.
Reported-by: <syzbot+f7c41a878676b72c16a6@syzkaller.appspotmail.com>
Signed-off-by: Ahmed Ehab <bottaawesome633@gmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
bkey_fsck_err() was added as an interface that looks like fsck_err(),
but previously all it did was ensure that the appropriate error counter
was incremented in the superblock.
This is a cleanup and bugfix patch that converts it to a wrapper around
fsck_err(). This is needed to fix an issue with the upgrade path to
disk_accounting_v3, where the "silent fix" error list now includes
bkey_fsck errors; fsck_err() handles this in a unified way, and since we
need to change printing of bkey fsck errors from the caller to the inner
bkey_fsck_err() calls, this ends up being a pretty big change.
Als,, rename .invalid() methods to .validate(), for clarity, while we're
changing the function signature anyways (to drop the printbuf argument).
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>
We've been moving away from going RW lazily; if we want to go RW we do
that in set_may_go_rw(), and if we didn't go RW we don't need to delete
dead snapshots.
Reported-by: syzbot+4366624c0b5aac4906cf@syzkaller.appspotmail.com
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>
