In a combined storage and filesystem session at the 2025 Linux Storage, Filesystem, Memory Management, and BPF Summit (LSFMM+BPF), Keith Busch led a discussion about zero-copy operations for the Filesystem in Userspace (FUSE) subsystem. The session was proposed by his colleague, David Wei, who could not make it to the summit, so Busch filled in, though he noted that "I do not really know FUSE so well". The idea is to eliminate data copies in the data path to and from the FUSE server in user space.
在 2025 年的 Linux 存储、文件系统、内存管理与 BPF 峰会（LSFMM+BPF）中，一场关于用户空间文件系统（FUSE）子系统的零拷贝操作的讨论由 Keith Busch 主持。这一议题是由他的同事 David Wei 提出的，但 Wei 未能出席峰会，因此由 Busch 临时代为主持，不过他也坦言：“我对 FUSE 并不是很熟”。这次讨论的核心思想是消除与用户空间 FUSE 服务器之间数据传输过程中的拷贝操作。
Busch began with some background on io_uring. When an application using io_uring needs to do read and write operations on its buffers, the kernel encapsulates those buffers twice, first into an iov_iter (of type ITER_UBUF) and from that into a bio_vec, which describes the parts of a block-I/O request. It does that for every such operation; "if you are using the same buffer, that's kind of costly and unnecessary". So io_uring added a way for applications to register a buffer; the kernel will create an iov_iter with the ITER_BVEC type just o