s3: route versioned PutObject finalize off the distributed lock
A versioned write's finalize (flip the .versions pointer to the newest version,
demote the prior latest) now runs as a single RECOMPUTE_LATEST ObjectTransaction
on the object's owner filer, under its per-path lock, instead of the unserialized
updateLatestVersionInDirectory. The version file is written first; the owner
re-derives the pointer by scanning the directory.
RECOMPUTE_LATEST gains size_to_key / mtime_to_key to cache the chosen version's
size and mtime on the pointer, and demote_key / demote_value to stamp the
displaced prior latest (NoncurrentSinceNs for lifecycle) when the pointer moves.
Falls back to updateLatestVersionInDirectory when no owner is known yet.
* filer: let PATCH_EXTENDED replace Entry.content
PATCH_EXTENDED merges extended attributes under the per-path lock, reading the
entry fresh, so concurrent patches to different keys don't clobber each other.
Some single-key state lives in Entry.content rather than an extended attribute
(e.g. the S3 bucket metadata blob). Add set_content/content to the mutation so a
patch can replace content the same way -- read fresh, set content, preserve the
rest -- letting a content write and an extended-attribute write on the same
entry serialize on the lock instead of racing whole-entry rewrites.
* Update weed/server/filer_grpc_server.go
Co-authored-by: gemini-code-assist[bot] <176961590+gemini-code-assist[bot]@users.noreply.github.com>
* filer: test set_content FileSize sync; note chosen content-patch approach
Cover the FileSize behavior of a set_content patch: a file's size follows the
new content length (including when it shrinks), a directory's stays zero. Also
document, in the bucket-config design, that extending PATCH_EXTENDED with
set_content is the implemented path for content-backed config.
---------
Co-authored-by: gemini-code-assist[bot] <176961590+gemini-code-assist[bot]@users.noreply.github.com>
A multi-object delete spans many keys that route to different owner filers. The
gateway groups keys by owner and sends one batch per owner; the filer applies
each transaction under its own per-path lock, independent of the others.
A failed transaction (precondition or mutation error) is reported in its own
response without aborting the rest, matching S3 multi-object semantics where
each key succeeds or fails on its own. There is no cross-key atomicity, which S3
batch delete does not require.
Deleting a specific version that happens to be the latest needs the new latest
re-derived from the remaining versions, and that scan must run under the same
lock as the delete. The gateway can't do it atomically across RPCs.
Add a RECOMPUTE_LATEST mutation: it scans a directory under the transaction
lock, picks the child that sorts last (descending) or first by name, copies the
mapped extended keys from it into a pointer entry, and stores its name under
name_to_key. An empty directory clears the pointer keys. The filer stays
mechanical and S3-agnostic: the caller, which knows the versioning scheme,
supplies the sort direction and the key mappings. A missing pointer entry is a
no-op, so a replayed transaction is idempotent.
A versioned object write touches several entries that must change together: the
main object, a delete marker or version file, and the latest pointer on the
.versions directory. Holding a distributed lock across separate RPCs to do this
is what the per-path lock was meant to replace, but a single CreateEntry only
covers one entry.
Add ObjectTransaction: a request carries a lock_key (the object path), an
optional WriteCondition, and an ordered list of mutations (PUT / DELETE /
PATCH_EXTENDED). The filer holds the per-path lock on lock_key for the whole
call, checks the condition against the entry at lock_key, then applies the
mutations in order. Callers route the object's writes to its owner filer so the
lock is authoritative across all of the object's entries.
DELETE and PATCH of an absent entry are no-ops, so a replayed transaction is
idempotent. PUT entries are metadata-scoped; data-bearing writes (chunks) are
written before the transaction, as today.
Chris Lu