- Use relaxed increment under the map bucket lock when duplicating file handles.
- Use acq_rel decrement when releasing and checking for final references.
- Load moved ref_count with relaxed ordering during map insertion.
- Explain that the mutex is per readdir call.
- Document that only dirent deduplication and list append are serialized.
- Clarify that per-branch opendir and getdents64 work runs outside the critical section.
- Replace the per-file Mutex with std::shared_mutex for shared write access.
- Run direct and cached writes under a shared lock while the fd is stable.
- Retry failed writes under a unique lock before move-on-ENOSPC relocation.
- Add helpers that release path locks and update node state under f.lock.
- Update getattr and setattr stat-cache invalidation while preserving ESTALE handling.
- Rework create, open, tmpfile, and set_path_info to mutate lookup/open state under the shared lock.
- Document the lock/unlock pair as an acquire/release barrier.
- Explain that releasedir waits for in-flight readdir calls before destroy/free.
- Warn against removing the synchronization despite it not being a critical section.
Important changes:
- Switch mergerfs and vendored libfuse Makefiles to -std=c++20.
- Select the latest available GCC/G++ or toolset in container builds.
- Verify compiler C++20 support during package installation.
- Fix dynamic SysLog formatting for fmt C++20 checks.
- Add mergerfs_mount() context manager in posix_parity.py that creates
temporary branch dirs in tests/.test_tmp/, mounts an ephemeral mergerfs
instance, and cleans up after use.
- Add find_mergerfs(), find_fusermount(), mount_mergerfs(), unmount_mergerfs()
helpers.
- Update run-tests to invoke each TEST_* script without a mountpoint arg.
- Update README.md to document the new `python3 tests/run-tests` invocation.
- Fix 44 tests to use mergerfs_mount() instead of expecting a pre-mounted path.
- Add tempfile import to 10 tests that were missing it.
- Fix TEST_mount_lifecycle to use mergerfs_mount() context manager.
- Fix TEST_posix_tmpfile missing join import.
- Fix TEST_cfg_xattr_modes error message framing (no "(known bug)").
- Fix TEST_posix_copy_file_range: loop-copy full size, compare st_size and
SHA256 hash; add NativeTmp for space management; route native temp to
tests/.test_tmp/ to avoid ENOSPC on /tmp.
- Fix TEST_posix_getattr_fgetattr: st_cmp skips st_size for dirs; add
compare_ino param for safe inode comparison when inodecalc=passthrough.
- Fix TEST_unlink_rename, TEST_use_* tests: namespace cleanup, consistent
variable naming, None check for cmpfunc.
- Fix TEST_readlink_semantics: remove type annotations to support older
Python; wrap in mergerfs_mount() try/except.
- Add flush=True to run-tests print so test names show immediately.
- Fix typo in static.installer: /pkg/ -> /pkgs/
- Add missing mkdir -p /build before makeself
- Mount pkgs directory via podman build -v so static.installer can access
previously built static tarballs without relying on bind mounts relative
to the build context
- Register qemu-user-static binfmt handlers for cross-compilation
- Make --git-repo optional when using --setup
- Reserve a zero stat CRC to represent an invalid cache fingerprint.
- Include device, size, inode, mtime, and ctime data in the fingerprint.
- Recompute the fingerprint during auto-cache open before keeping cache.
- Make the test runner fail on failed tests and report explicit skips
- Strengthen assertions for O_DIRECT, LUP policy, EXDEV fallback, and xattrs
- Fix cleanup and file descriptor handling across test scripts
No functional change: libfuse/helper.cpp (fuse_daemonize,
fuse_helper_opt_proc, fuse_parse_cmdline) and mergerfs
fuse_init.cpp (_want helpers) reformatted to match the project's
GNU-style brace placement and aligned parameter lists.
- fuse_opt: reformat process_opt_param to project style; return the
rv from sscanf through a named local so the error branch prints
the failing option cleanly.
- cpu.cpp: when parsing /sys/devices/system/cpu/*/topology/core_id,
bail out cleanly on stream read failure rather than recording an
uninitialized core_id.
- fusermount: free(copy) on the success path of parsing the mount
option (previously leaked on every mount), and replace the fixed-
buffer sprintf into procfile with snprintf bounded by the buffer
size.
- maintenance_thread: widen the iteration count from int to u64
so a long-lived daemon doesn't wrap after ~68 years of ticks
(real effect: silence signed-overflow warnings under UBSan).
- ThreadPool::destroy used to iterate _threads directly while another
thread could be adjusting the same vector. Snapshot the vector
under the mutex and iterate the local copy for pthread_cancel /
pthread_join.
- ObjPool::construct now returns NULL when the pooled allocator
returns NULL instead of invoking placement-new on a null
pointer. In destroy, compute to_node(obj) before running the
destructor - the destructor may scrub bytes the to_node helper
reads.
- In the async/sync workers in fuse_loop, msgbuf_alloc can return
NULL under memory pressure. Fail the worker cleanly with a
diagnostic rather than dereferencing. Also introduce a small
_nproc() helper that treats hardware_concurrency()==0 as 1, so
the downstream min/max arithmetic doesn't produce a zero thread
count.
The signal handler reads the global session pointer from an async-
signal context while another thread installs/removes the session
via set/remove_signal_handlers. Use std::atomic<fuse_session*> with
acquire/release ordering so the handler either sees NULL or a fully
published session, never a torn pointer.
Collapse get_node/get_node_nocheck into a single function that
returns NULL when the node is absent rather than abort()ing.
Callers that previously assumed non-NULL now check the return value
and either reply ESTALE/ENOMEM or fall through gracefully; a few
places where the node is load-bearing (e.g. unhash during remove)
use fatal::abort with a descriptive message.
Switch mutex_lock / mutex_unlock pairs to mutex_lockguard so early
returns on error paths no longer leak the lock, and add NULL-safety
around fuse_dh in readdir/readdir_plus, fuse_dirents_init error
returns, the getattr path when both name and fh are empty, and the
msgbuf allocation in fuse_lib_read.
Pull the new xstrdup/xmalloc wrappers from xalloc.hpp for the root
node name so the common-case OOM path terminates with a diagnostic
instead of a silent corrupted node.
Also guard fuse_session_destroy against a NULL session - called
from error-recovery paths.
The low-level init/destroy callbacks were passed a userdata pointer
that mergerfs never consumed - the caller threaded it through
fuse_lowlevel_new only to hand it back unchanged. Remove the
parameter from the ops struct, from fuse_lowlevel_new(_common),
and from the internal fuse_ll struct; update fuse_lib_init and
fuse_lib_destroy accordingly.
Also drop fuse_reply_ioctl_iov: no caller in-tree invokes it and
the public API is defined by this vendored libfuse fork.
libfuse previously initialized its debug log filepath to
"/dev/stderr", forcing the config layer to reopen stderr on every
load whether or not the user asked for it. Default the libfuse log
path to "" and have the mergerfs config layer only forward the
request to libfuse when the user supplied an explicit path.
Both helpers previously called strcmp/pointer-dereference directly
on their arguments, so a stray NULL (e.g. an unset env string or an
absent xattr) crashed the process. Guard both helpers: same()
returns true only if both pointers are equal, startswith() returns
false if either side is NULL.
The create policy can legitimately return success with an empty
destination list (e.g. every candidate rejected). Previously we
then dereferenced dst_branch[0] and faulted. Return -ENOSPC so the
original write that triggered the move propagates a sensible errno
to userspace.
The branch-aggregation code computed
blocks * f_frsize / min_frsize
as u64 arithmetic. With large filesystems the intermediate product
blocks * f_frsize overflows 64 bits long before the division can
bring the result back into range, producing garbage bavail/bfree
values reported to userspace.
Compute the scale factor once in long double and multiply each
count by it, so the only narrowing happens in the final cast back
to fsblkcnt_t.
Old code only null-terminated when the returned/copied length was
strictly less than the caller-supplied bufsize_, leaving the buffer
unterminated on an exact-fill. Since buf_ is consumed as a C string,
reserve one byte for the terminator up front and unconditionally
terminate.
- ReadDir::_initialized is set by the first thread through the
lazy-init path and read by every subsequent caller; make it
std::atomic<bool> so the read/write pair has a happens-before
relationship.
- The 'no valid mergerfs branch found' error directory entry used
strcpy into a fixed-size dirent buffer. The message happens to
fit today but the buffer is only NAME_MAX wide; switch to a
length-bounded strncpy driven by the constexpr string size.
- The getdents implementations for seq/cor/cosr allocated a msgbuf
without checking for allocation failure and then dereferenced it.
Return -ENOMEM when the allocation fails.
The fake-root and control-file fast paths returned a synthetic stat
without touching the timeout struct. Callers that took those paths
ended up sending whatever the timeout struct happened to hold,
which is uninitialized memory for the control-file path and
whatever a prior call left there for the fake-root path. Kernel
behavior is undefined when the timeout is garbage.
Pass timeout_ into both helpers and set entry/attr from the
configured cache values.
Previously most FUSE ops took a reference to the live cfg.branches
object. With atomic_load now producing a shared_ptr snapshot, pass
it by value: the op works against a single stable view of the
configuration for its whole lifetime, immune to concurrent
reconfiguration.
Also bail out with -ENOENT when the policy returns an empty branch
set rather than dereferencing branches[0]. This was reachable if a
policy rejected every branch (e.g. everything readonly while
looking for a writable target).
Covers access, chmod, chown, create, getattr, getxattr, ioctl,
link, listxattr, mkdir, mknod, open, readdir (cor/cosr),
readlink, removexattr, rename, rmdir, setxattr, statfs, statx,
symlink, truncate, unlink, utimens.
While here, in _getattr only dereference st_->st_mode when lstat
succeeded (it is otherwise uninitialized).
Several FUSE ops fell back to looking up a FileInfo via
state.open_files when the kernel-provided fh was zero, returning
-ENOENT if the lookup failed. This path papered over handle-tracking
bugs and added cost on every call. Use the handle directly and
return -EBADF when it is invalid - the kernel should always hand us
a valid fh for an open resource.
Also simplify FileInfo::from_fh / DirInfo::from_fh and their to_fh
helpers: callers now handle the null-pointer case explicitly so the
ASSERT_NOT_NULL checks are redundant.
Covers fallocate, fchmod, fchown, fgetattr, flock, ftruncate,
futimens, read, release, releasedir, write, statx, ioctl (file +
dir), readdir (sequential, concurrent-on-read,
concurrent-on-search), and the passthrough fast paths in
create/open.
Antonio SJ Musumeci