[PR #367] fix(io): Add robust symlink cleanup to prevent resource leakage #391

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opened 2026-10-26 09:49:44 +00:00 by bsakaguchi · 0 comments

bsakaguchi commented

2026-10-26 09:49:44 +00:00

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📋 Pull Request Information

Original PR: https://github.com/deepseek-ai/3FS/pull/367
Author: @yurekami
Created: 12/25/2025
Status: 🔄 Open

Base: main ← Head: fix/iovec-symlink-cleanup

📝 Commits (1)

b250b38 fix(io): Add robust symlink cleanup to prevent resource leakage

📊 Changes

1 file changed (+106 additions, -1 deletions)

View changed files

📝 hf3fs_fuse/io.py (+106 -1)

📄 Description

Summary

Adds context manager support (__enter__/__exit__) to iovec and ioring classes for Pythonic resource management
Adds atexit handler to clean up orphaned symlinks on normal process exit
Adds global thread-safe symlink registry to track active symlinks
Adds explicit close() methods with idempotent behavior for manual cleanup

Fixes #334 - Shared memory leakage due to symlinks not being properly deleted

Changes

The iovec class creates symlinks in /3fs-virt/iovs/ that point to shared memory. Previously, cleanup only happened in __del__, which is unreliable in Python (not guaranteed to run, timing issues, exception handling problems).

This PR improves cleanup reliability by:

Context manager support: Users can now use with make_iovec(...) as iov: for automatic cleanup
Atexit handler: Registered at module load to clean up any remaining symlinks on exit
Global registry: Thread-safe tracking of active symlinks for cleanup coordination
Explicit close(): Idempotent method that can be called safely multiple times

Example usage:

# Preferred: using context manager (new)
with make_iovec(shm, mount_point) as iov:
    ior.prepare(iov[:], True, fd, offset)
    # ...
# symlink automatically cleaned up

# Alternative: manual management
iov = make_iovec(shm, mount_point)
try:
    # use iov
finally:
    iov.close()  # explicit cleanup

Test plan

Verify symlinks are cleaned up when using context manager
Verify symlinks are cleaned up on normal process exit via atexit
Verify symlinks are cleaned up when exception occurs in context
Verify thread-safety of global registry under concurrent access
Verify backward compatibility with existing code using __del__

🤖 Generated with Claude Code

_{🔄 This issue represents a GitHub Pull Request. It cannot be merged through Gitea due to API limitations.}

## 📋 Pull Request Information **Original PR:** https://github.com/deepseek-ai/3FS/pull/367 **Author:** [@yurekami](https://github.com/yurekami) **Created:** 12/25/2025 **Status:** 🔄 Open **Base:** `main` ← **Head:** `fix/iovec-symlink-cleanup` --- ### 📝 Commits (1) - [`b250b38`](https://github.com/deepseek-ai/3FS/commit/b250b38282e544ffba7b3800a9ec9238baacd01d) fix(io): Add robust symlink cleanup to prevent resource leakage ### 📊 Changes **1 file changed** (+106 additions, -1 deletions) <details> <summary>View changed files</summary> 📝 `hf3fs_fuse/io.py` (+106 -1) </details> ### 📄 Description ## Summary - Adds context manager support (`__enter__`/`__exit__`) to `iovec` and `ioring` classes for Pythonic resource management - Adds `atexit` handler to clean up orphaned symlinks on normal process exit - Adds global thread-safe symlink registry to track active symlinks - Adds explicit `close()` methods with idempotent behavior for manual cleanup ## Related Issue Fixes #334 - Shared memory leakage due to symlinks not being properly deleted ## Changes The `iovec` class creates symlinks in `/3fs-virt/iovs/` that point to shared memory. Previously, cleanup only happened in `__del__`, which is unreliable in Python (not guaranteed to run, timing issues, exception handling problems). This PR improves cleanup reliability by: 1. **Context manager support**: Users can now use `with make_iovec(...) as iov:` for automatic cleanup 2. **Atexit handler**: Registered at module load to clean up any remaining symlinks on exit 3. **Global registry**: Thread-safe tracking of active symlinks for cleanup coordination 4. **Explicit close()**: Idempotent method that can be called safely multiple times ### Example usage: ```python # Preferred: using context manager (new) with make_iovec(shm, mount_point) as iov: ior.prepare(iov[:], True, fd, offset) # ... # symlink automatically cleaned up # Alternative: manual management iov = make_iovec(shm, mount_point) try: # use iov finally: iov.close() # explicit cleanup ``` ## Test plan - [ ] Verify symlinks are cleaned up when using context manager - [ ] Verify symlinks are cleaned up on normal process exit via atexit - [ ] Verify symlinks are cleaned up when exception occurs in context - [ ] Verify thread-safety of global registry under concurrent access - [ ] Verify backward compatibility with existing code using `__del__` 🤖 Generated with [Claude Code](https://claude.com/claude-code) --- <sub>🔄 This issue represents a GitHub Pull Request. It cannot be merged through Gitea due to API limitations.</sub>

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2026-10-26 09:49:44 +00:00

bsakaguchi referenced this issue

2026-10-26 09:50:01 +00:00

[PR #392] [MERGED] Clarify speed_up_quit() test usage violates documented safety contract #409