- 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.
Branches using the default minfreespace held a reference to their
owning Impl's _default_minfreespace. After a copy or move the
pointer still referenced the source Impl, which could become
invalid or diverge after further configuration changes. Switch to
a pointer and re-link it to the destination Impl on copy/move.
While here, convert set_branch_mode to do an atomic_store of a
newly constructed Impl rather than mutating the shared pointer
target in place. Readers holding an atomic_load snapshot are no
longer affected by a concurrent mode change.
ref_count is read and written from multiple FUSE worker threads
during open/release. Make it std::atomic<int> and provide a move
constructor so OpenFile remains movable when the underlying atomic
is non-movable.
rwlock.hpp was left over after migrating to atomic shared pointers
for branches configuration. No code references ReadGuard/WriteGuard
any longer, so drop the header and its stale includes.
