The mutation-fragment-based streaming path in `stream_session.cc` did not check whether the receiving node was in critical disk utilization mode before accepting incoming mutation fragments. This meant that operations like `nodetool refresh --load-and-stream`, which stream data through the `STREAM_MUTATION_FRAGMENTS` RPC handler, could push data onto a node that had already reached critical disk usage.
The file-based streaming path in stream_blob.cc already had this protection, but the load&stream path was missing it.
This patch adds a check for `is_in_critical_disk_utilization_mode()` in the `stream_mutation_fragments` handler in `stream_session.cc`, throwing a `replica::critical_disk_utilization_exception` when the node is at critical disk usage. This mirrors the existing protection in the blob streaming path and closes the gap that allowed data to be written to a node that should have been rejecting all incoming writes.
Fixes https://scylladb.atlassian.net/browse/SCYLLADB-901
The out of space prevention mechanism was introduced in 2025.4. The fix should be backported there and all later versions.
Closesscylladb/scylladb#28873
* github.com:scylladb/scylladb:
streaming: reject mutation fragments on critical disk utilization
test/cluster/storage: Add a reproducer for load-and-stream out-of-space rejection
sstables: clean up TemporaryHashes file in wipe()
sstables: add error injection point in write_components
test/cluster/storage: extract validate_data_existence to module scope
test/cluster: enable suppress_disk_space_threshold_checks in tests using data_file_capacity
utils/disk_space_monitor: add error injection to suppress threshold checks
69c58c6589