Files
seaweedfs/weed/storage
Chris Lu 9bafeb6139 ec: refuse to mount a 0-byte shard file when the index has entries (#11030)
* ec: refuse to mount a 0-byte shard file when the index has entries

The startup scan already skips (and eventually deletes) zero-sized shard
files as residue of a failed copy, but the mount RPC path opens the file
directly with no size check, so an explicit VolumeEcShardsMount over a
truncated file registers a size-0 claim. A registered empty shard serves
nothing while advertising ownership: with placement pinned to the owning
disk, it would keep attracting re-copies to a file that was never valid.

The one legitimate 0-byte shard is the empty volume's: encoding a volume
with no live needles produces a 0-byte .ecx and 0-byte shards, and that
mount must keep working (TestMountEcShards_EmptyEcxMountsSuccessfully).
So the gate compares against the index: AddEcVolumeShard (Go) and
EcVolume::add_shard (Rust) refuse a 0-byte shard file only when the
volume's .ecx has entries. Go's AddEcVolumeShard grows an error return
for this; the loader cleans up the refused shard and, when it just
created the EcVolume, unregisters that too. The mount loop already
collects non-ENOENT failures per disk and keeps scanning, so a sibling
disk holding a real copy still wins.

Regression tests in both trees: an empty shard beside an index with
entries is refused and leaves nothing registered; an empty shard of an
empty volume still mounts.

Claude-Session: https://claude.ai/code/session_01AWpefvdi4U3HLng18x5CJ9

* ec: release the duplicate shard when a mount retry re-loads it

Review follow-up: AddEcVolumeShard keeps the existing shard and reports
added=false for a shard this disk already registered, but the loader
discarded that result, so every retried LoadEcShard leaked the duplicate
it had just opened — an fd and a mount-gauge increment per retry. Release
both and return the existing volume. Regression test pins the gauge.

Claude-Session: https://claude.ai/code/session_01AWpefvdi4U3HLng18x5CJ9

* ec: close the test DiskLocation instead of only its EC volumes

Review follow-up: DiskLocation.Close() also stops the background
goroutine NewDiskLocation starts; closeEcVolumes left it running for the
rest of the test process. Both uses are this PR's own tests.

Claude-Session: https://claude.ai/code/session_01AWpefvdi4U3HLng18x5CJ9

* rust: unregister the just-created EcVolume when its first mount is refused

Review follow-up: when the first mount of a volume rejects its shard
(e.g. the new 0-byte-beside-nonempty-index refusal), the Rust mount path
had already inserted the EcVolume and propagated the error without
removing it — a zero-shard registration advertising a mount that serves
no data while pinning the .ecx/.ecj descriptors (and, since placement's
mounted tier keys off it, steering shard placement at this disk). Remove
it on the way out, exactly as the Go loader already does; a volume that
already holds shards keeps them (the RPC's first-error-aborts contract).
Regression test covers both.

Claude-Session: https://claude.ai/code/session_01AWpefvdi4U3HLng18x5CJ9

* rust: skip already mounted shards on a mount retry

Review follow-up: EcVolume::add_shard replaces self.shards[id] for a
shard the volume already holds, and the mount loop then bumps the
ec_shards gauge although the mounted count did not grow — gauge drift on
every mount retry, and a serving fd swapped for no reason. Skip shard
ids the volume already reports, mirroring Go's AddEcVolumeShard
added=false handling. Regression test pins the gauge across a duplicate
mount (unique collection label: the gauge is process-global and tests
run in parallel).

Claude-Session: https://claude.ai/code/session_01AWpefvdi4U3HLng18x5CJ9
2026-08-29 14:19:16 -07:00
..
2025-06-30 13:57:28 -07:00
2019-04-17 22:04:49 -07:00
2025-06-16 22:05:06 -07:00