Four bugs caused data mismatches between PUT and GET operations:
1. chunk_store_exists() used file_open (O_CREAT) to check if a chunk
file exists, which created empty files as a side effect. Servers
would then read from these empty files and return uninitialized
heap memory as chunk data. Fixed by using file_exists (access())
instead.
2. Server's process_fetch_chunk checked `ret < 0` after
chunk_store_read, missing the EOF case (ret == 0) from empty
files. Changed to `ret <= 0`.
3. begin_transfers() == 0 was used as a completion check in both
STEP_FETCH_CHUNK and STEP_STORE_CHUNK, but returning 0 only means
"no new transfers started", not "all done". With concurrent chunk
transfers, this caused premature completion, leaving in-flight
transfers to hit UNREACHABLE. Fixed by using
all_chunk_transfers_completed() instead.
4. choose_store_locations_for_chunk() returned [0, 1] for ALL chunks
regardless of index, while GET fetches chunk i from servers
(i+j) % num_servers. This made some chunks unreachable. Fixed by
using (chunk_idx + j) % num_servers for store locations.
Also added SO_REUSEADDR to the server listen socket so restarting
the cluster doesn't fail with "Couldn't setup TCP listener", and
added a note on mock_access about the simulation mismatch.
https://claude.ai/code/session_01JniNxxDP4NbsDXNGmGNG7H
Introduce a Makefile that builds libtoastyfs.a and libtoastyfs.so from the
client-side sources (client, tcp, byte_queue, message, basic) so external
programs can link against the ToastyFS client API in include/toastyfs.h.
Add cluster.sh, a convenience script that manages a local 3-node cluster
by spawning toastyfs server processes on ports 8081-8083. Sub-commands:
up, down, status, logs, and "run <source.c>" which builds the library,
compiles the source against it, starts the cluster, runs the binary, and
tears everything down.
Add examples/example.c demonstrating synchronous PUT, GET, DELETE, and a
NOT_FOUND verification.
Fix a stack overflow in the MAIN_SERVER entry point: ServerState is ~40 MB
(MetaStore holds 4096 ObjectMeta entries) and was declared on the stack.
Heap-allocate it instead.
https://claude.ai/code/session_019DVhmc25jfzcHnmdNxzib2
Adds support for automatically creating files when write operations target
non-existent files. This is essential for REST PUT operations which should
be able to create new resources.
Implementation:
- Added TOASTY_WRITE_CREATE_IF_MISSING flag to ToastyFS API header
- Updated toasty_write() and toasty_begin_write() to accept flags parameter
- Client sends write flags in MESSAGE_TYPE_WRITE message to metadata server
- Metadata server parses flags and handles file auto-creation atomically:
* When write fails with FILETREE_NOENT and flag is set
* Logs creation to WAL for crash consistency
* Creates file with default 4096-byte chunk size
* Retries write with newly created file's generation tag
- Updated web proxy PUT handler to use TOASTY_WRITE_CREATE_IF_MISSING
- Updated examples and simulation client for new API signature
Benefits:
- Works for both sync and async APIs
- Single round trip (atomic server-side operation)
- Prevents race conditions
- Proper WAL logging ensures crash consistency
cozis
Claude