On 12/22/20 11:48 PM, Christoph Hellwig wrote: > FYI, a few years ago I spent some time helping a customer to prepare > their block device in userspace using fuse code for upstreaming, but > at some point they abandoned the project. But if for some reason we > don't want to use nbd I think a driver using the fuse infrastructure > would be the next logical choice. Hi Christoph, Thanks for having shared this information. Since I'm not familiar with the FUSE code: does this mean translating block device accesses into FUSE_READ and FUSE_WRITE messages? Does the FUSE kernel code only support exchanging such messages between kernel and user space via the read() and write() system calls? I'm asking this since there is already an interface in the Linux kernel for implementing block devices in user space that uses another approach, namely a ring buffer for messages and data that is shared between kernel and user space (documented in Documentation/target/tcmu-design.rst). Is one system call per read and per write operation fast enough for all block-device-in-user-space implementations? Thanks, Bart. -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
