Commit Graph
2 Commits
Author SHA1 Message Date
103328e70f filer: create parent directories for lazily fetched remote entries (#11727)
* filer: create parent directories for lazily fetched remote entries

A remote-mounted object first read through the filer was persisted without
its parent directories, so remote.uncache and the remote cache evictor, which
walk down from the mount directory, never reached it: its cached chunks could
not be evicted.

Persist the missing parents with the entry. With those directories in place,
the empty-folder cleaner leaves folders under a remote mount alone: deleting
one removes its whole prefix on the remote, which can still hold objects
that were never read locally.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* filer: keep remote objects at parent keys and remote prefixes of empty folders

Look up a lazily fetched entry's missing parents through lazy fetch before
creating them, so a remote object stored at a parent's key is materialized
and promoted to a prefix object rather than hidden behind a new directory.

Deleting a folder that is empty in the filer is metadata-only under a remote
mount, both for a non-recursive delete and for the expiry cleanup of empty
parents: the mount is populated lazily, so the folder can still hold remote
objects never read, and removing its remote directory deletes every object
under that prefix. This replaces the empty-folder cleaner's own guard, which
covered only one of those paths.

A metadata-only delete records no remote-deletion tombstone, locally or from
its metadata event: nothing is owed to the remote, so lazy reads stay open.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* filer: stop the lazy parent lookup at a store error

Only a parent the store reports as not found is missing; a parent it cannot
read ends the walk, so the lookup does not stat ancestors above it on the
remote.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* filer: stat each missing remote parent once

A lazy fetch that finds k missing parents asked FindEntry for each, and every nested fetch re-walked its own still-missing ancestors, re-stating remote keys already proven absent: 1+k(k+1)/2 remote stats for one first read. The flagged parent lookups now skip their own walk; their entries are created by the same CreateEntry that already persists the chain.

* filer: materialize parents for lazily listed remote entries

maybeLazyListFromRemote persisted children and the listing directory with skipCreateParentDir, so a first access that goes through the list path still left entries unreachable to a walk from the mount directory. Materialize the missing ancestors the same way the lazy fetch does, and let the synced_at directory create its parent chain.

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Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>
Co-authored-by: Chris Lu <chris.lu@gmail.com>
2026-10-15 16:23:33 -07:00
Chris LuandDevin 2f6c237238 filer: keep lazy remote reads from resurrecting deleted paths (#11452)
* filer: keep lazy remote reads from resurrecting deleted paths

Under a remote mount with filer.remote.sync as write-back, a path that
was deleted or renamed away could come back as a chunkless remote-only
entry: between the local delete and the daemon's remote delete, a store
miss made maybeLazyFetchFromRemote trust a bucket that was behind the
filer. The ghost then outlived the remote object -- HEAD answered 200,
GET failed, and nothing cleaned it up.

The filer now tombstones paths it deletes under a remote mount, learned
both synchronously from its own delete path and from peer metadata
events. The lazy fetch and the lazy listing skip a tombstoned path until
the path is written again, until the mount's persisted write-back sync
offset has passed the delete event (the remote delete has landed), or
until a generous TTL covers a mount without a daemon.

Fixes #11440

Generated with [Devin](https://devin.ai)

Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>

* filer: cover recursive remote deletes with an ancestor tombstone

A recursive delete now records the directory tombstone before walking
children, so a partial traversal or a store that drops the subtree
without listing it still leaves every descendant covered. Directory
tombstones also subsume older descendant entries on add, descendant
adds covered by a standing ancestor are skipped, and an existing
tombstone can be refreshed even at capacity.

Generated with [Devin](https://devin.ai)

Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>

* filer: scope remote tombstones to the deleted object's generation

A remote object whose own mtime postdates the local delete is a new
generation, not the one the tombstone hides, so a recreated directory
can surface remote writes made after its delete while old-generation
objects stay hidden. Lazy fetch now stats the remote object before
deciding, listings pass each child's remote mtime, and a sync offset
releases a tombstone once it reaches the delete's own timestamp.

Generated with [Devin](https://devin.ai)

Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>

* filer: rebuild remote deletion tombstones after restart

In-memory tombstones are lost on restart while remote write-back
offsets persist, so a filer boot replays the persisted metadata log
from the oldest mount offset and folds deletes back into the tombstone
set through the same event handler. Lazy remote reads hold off while
the replay runs so a pending delete cannot resurrect in the gap.

Generated with [Devin](https://devin.ai)

Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>

* filer: release remote tombstones only after their delete event lands

The write-back offset orders against event timestamps, but the synchronous
delete path recorded tombstones with the local clock before its event was
emitted — a later unrelated event could already have pushed the mount's
watermark past that guess, releasing the tombstone before the daemon
applied the delete. Tombstones recorded ahead of their event are now
marked pending and can only be lifted by the event confirming them or by
TTL; event-stamped tombstones release through the offset as before.

The remote-mtime generation bypass is dropped: remote and filer clocks
are independent, and a pending remote delete removes whatever object sits
at the path, so a "newer" remote object would only resurrect as a
phantom. Tombstoned lookups now skip the remote stat entirely.

Generated with [Devin](https://devin.ai)

Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>

* filer: drop dir tombstone when recursive delete fails before listing

The ancestor tombstone is recorded before the child listing; if that
listing fails nothing was deleted, and the leftover tombstone would hide
still-existing remote children for the whole TTL. Tombstones for children
already deleted stay, since their remote deletes are still owed.

Generated with [Devin](https://devin.ai)

Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>

* filer: block lazy remote reads on startup tombstone rebuild

The rebuild gate is now a done-channel set synchronously before the
replay goroutine starts, so no lazy read can slip through in between.
Reads wait on it with context cancellation instead of returning an
empty miss that makes remote-only objects look deleted.

The replay start is floored at now-TTL: mounts without a recorded
write-back offset previously replayed the whole persisted history, and
events older than the TTL would only build already-expired tombstones.
The gate check now runs after the mount lookup so replaying the meta
log's own directory listings does not deadlock on the gate, and the
replay retries with backoff until it succeeds instead of failing open.

Generated with [Devin](https://devin.ai)

Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>

* filer: mark restamped tombstone pending until its delete event lands

When a local delete raises an existing tombstone's timestamp, the new
value is only a local clock guess ahead of that delete's event. Leaving
the tombstone un-pending lets a write-back offset release it before the
event is actually consumed, reopening the resurrection window.

Generated with [Devin](https://devin.ai)

Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>

* filer: bound tombstone replay to the tombstone TTL

Persisted-log replay retried forever, keeping lazy remote reads gated
indefinitely when the log cannot be read. Cap retries at the tombstone
TTL measured from replay start: past that point every tombstone would
have expired anyway, so opening the gate loses no protection.

Generated with [Devin](https://devin.ai)

Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>

* filer: re-check deletion tombstone before persisting lazy fetch

A delete landing while StatFile is in flight passed the earlier
tombstone check but still persisted the fetched entry, resurrecting a
path whose remote delete is pending. Re-check right before CreateEntry.

Generated with [Devin](https://devin.ai)

Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>

* filer: retract a lazily persisted entry when a delete raced the insert

The pre-insert tombstone check still leaves a window between the check
and the store insert. Since deletes always record the tombstone before
removing the entry, a tombstone visible right after a successful insert
means the delete already ran: delete the entry back out so the
tombstoned path stays deleted.

Generated with [Devin](https://devin.ai)

Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>

* filer: note why the replay deadline can safely open the gate

Deletes made after startup are captured by the live delete and event
paths, so a stalled replay can only be missing pre-restart deletes, all
of which are past the tombstone TTL by the deadline.

Generated with [Devin](https://devin.ai)

Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>

* filer: retract only the entry a lazy remote read materialized

Deleting by path after a raced delete could remove a legitimate rewrite
that replaced the fetched entry. Verify the stored entry still matches
the remote object (or the just-created directory shape) before deleting,
and apply the same post-insert check to lazy listing children.

Generated with [Devin](https://devin.ai)

Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>

* filer: require full-entry equality before retracting a lazy entry

Remote-only matching still removed a write that had updated the fetched
entry, e.g. appended chunks. Compare the persisted entry against what
this read materialized; any change means a real update owns the path.

Generated with [Devin](https://devin.ai)

Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>

---------

Co-authored-by: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>
2026-09-26 08:00:39 +08:00