The Link and CopyFileRange FUSE request handlers were calling
fuseServer.InodeNotify (and EntryNotify for copy) synchronously while
the kernel was still waiting for the request's reply on the same
/dev/fuse fd. Notifications share that fd, so the syscall.Write can
block indefinitely when the kernel hasn't drained its queue yet,
hanging the entire mount. A goroutine dump from a stuck mount showed
the Link handler blocked in syscall.Write inside InodeNotify while the
server's read loop kept waiting for new requests.
Drop the synchronous notifies. The local meta cache is still updated
inline, so subsequent filesystem ops see the fresh state; the kernel's
attr/dentry caches re-fetch once their TTL expires.
Chris LuandGitHub
7916e61c08