This adds a new configuration option ConcurrentFileUploadLimit that limits
the number of concurrent file uploads based on file count, complementing
the existing ConcurrentUploadLimit which limits based on total data size.
This addresses an OOM vulnerability where requests with missing/zero
Content-Length headers could bypass the size-based rate limiter.
Changes:
- Add ConcurrentUploadLimit and ConcurrentFileUploadLimit fields to S3ApiServerOption
- Add inFlightDataSize, inFlightUploads, and inFlightDataLimitCond to S3ApiServer
- Add s3a reference to CircuitBreaker for upload limiting
- Enhance CircuitBreaker.Limit() to apply upload limiting for write actions
- Add -concurrentUploadLimitMB and -concurrentFileUploadLimit command line flags
- Add s3.concurrentUploadLimitMB and s3.concurrentFileUploadLimit flags to filer command
The upload limiting is integrated into the existing CircuitBreaker.Limit()
function, avoiding creation of new wrapper functions and reusing the existing
handler registration pattern.
Fixes#7529