Files
seaweedfs/weed/replication
675020b342 fix(filer.sync): validate chunk size in FilerSink to prevent 0-byte propagation (#9701)
* fix(filer.sync): validate chunk size in FilerSink to prevent 0-byte propagation

FilerSink.fetchAndWrite previously trusted the source response and the
upload result blindly: a 200 OK / Content-Length: 0 reply from a broken
source volume was happily uploaded as a 0-byte needle to the destination,
and the destination filer metadata was then written with the source
chunk size. The result was permanent silent corruption -- ls shows the
file at its original size but reads fail with EIO.

Add two cheap defenses inside fetchAndWrite:

  1. After assembling fullData, compare its length against sourceChunk.Size.
  2. After a successful upload, compare uploadResult.Size against
     sourceChunk.Size.

Both checks wrap a new sentinel errChunkSizeMismatch that the retry
callback recognizes and refuses to retry -- needle.size=0 on disk is a
persistent state, not a transient network error, so the sync should stop
loudly on the affected entry instead of looping or, worse, silently
propagating it.

Tests:

  * TestValidateReplicatedChunkSize -- table-driven coverage of healthy,
    legitimately empty, zero-byte read, short read, and truncated upload
    cases.
  * TestFetchAndWriteRejectsZeroByteSource -- end-to-end: an httptest
    source that returns 200 OK with an empty body must cause fetchAndWrite
    to return errChunkSizeMismatch after exactly one source hit (fail
    fast, no retry storm).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

* filer.sync: bubble size-mismatch past CreateEntry/UpdateEntry

Three follow-ups on the chunk-size validation:

- Use %w in replicateOneChunk so the errChunkSizeMismatch sentinel
  survives the wrap and reaches errors.Is callers up the stack.
- In FilerSink.CreateEntry/UpdateEntry, surface errChunkSizeMismatch
  instead of warning-and-nil. Other errors (deleted source chunk,
  transient network) keep the existing swallow so a hiccup doesn't
  stall the stream.
- Drop validateReplicatedUploadSize: uploadResult.Size is set
  client-side from the same len(fullData) we already validated
  pre-upload, so the second check can't fail.

Test: scope the RetryWaitTime override to the one test that needs it,
add a regression that locks in the errors.Is chain through
replicateChunks.

---------

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Co-authored-by: Chris Lu <chris.lu@gmail.com>
2026-05-26 20:47:53 -07:00
..
2026-04-10 17:31:14 -07:00