Hi, This series: - Fixes some bugs/minor inconveniences, - Removes libfuse from the request processing path, - Make the FUSE export use coroutines for request handling,
More detail on the v1 cover letter: https://lists.nongnu.org/archive/html/qemu-block/2025-03/msg00359.html v2 cover letter: https://lists.nongnu.org/archive/html/qemu-block/2025-06/msg00040.html v3 cover letter: https://lists.nongnu.org/archive/html/qemu-block/2025-07/msg00005.html I noticed some performance differences vs. my previous benchmarks; notably, performance didn’t improve with the introduction of coroutines much (except for random read performance). However, when I run the same benchmarks on the old branch again, I see no performance improvement either. Something about my host system must have changed. Changes from v3: - Patch 1: Use QEMU_AUTO_VFREE - Patch 6: Added (fix for pre-existing bug) - Patch 11: Make flag atomic, better this way for multithreading later - Patch 12: Rename not only in fuse_write(), but fuse_read() as well - Patch 13: Added (don’t truncate if we don’t want to test that) - Patch 14: Added (fix for pre-existing bugs) - Patch 16: Rewrote core parts: - Remove the macros to handle different FUSE requests in the same buffer, instead use unions - Restructure how we read data from FUSE: No longer one request_buf per queue, but instead a non-WRITE buffer on the stack, and a WRITE data buffer on the heap. We pass this via readv(), but it means that for non-WRITE requests, data that we want on the stack may spill into the heap buffer, so we need to copy it back. We cache the data buffer between non-WRITE requests so we at least don’t have to reallocate it all the time. - Actually take care of older FUSE versions down to 7.9 (2007) - Handle some more requests that should be handled: STATFS, DESTROY, FORGET, BATCH_FORGET - Don’t handle short writes on /dev/fuse - Move initializing fuse_out_header into the callers of fuse_write_response() and fuse_write_buf_response() - Patch 18: Rebase conflicts because of patch 16, and removed the unused FuseRequestCoParam - Patch 19: Adhere to QAPI max line length - Patch 21: Added, not sure if absolutely necessary, but won’t hurt either - Patch 22: Rebase conflicts because of patch 16 git-backport-diff from v3: Key: [----] : patches are identical [####] : number of functional differences between upstream/downstream patch [down] : patch is downstream-only The flags [FC] indicate (F)unctional and (C)ontextual differences, respectively 001/24:[0009] [FC] 'fuse: Copy write buffer content before polling' 002/24:[----] [--] 'fuse: Ensure init clean-up even with error_fatal' 003/24:[----] [--] 'fuse: Remove superfluous empty line' 004/24:[----] [--] 'fuse: Explicitly set inode ID to 1' 005/24:[----] [--] 'fuse: Change setup_... to mount_fuse_export()' 006/24:[down] 'fuse: Destroy session on mount_fuse_export() fail' 007/24:[----] [--] 'fuse: Fix mount options' 008/24:[----] [--] 'fuse: Set direct_io and parallel_direct_writes' 009/24:[----] [--] 'fuse: Introduce fuse_{at,de}tach_handlers()' 010/24:[----] [--] 'fuse: Introduce fuse_{inc,dec}_in_flight()' 011/24:[0008] [FC] 'fuse: Add halted flag' 012/24:[0012] [FC] 'fuse: fuse_{read,write}: Rename length to blk_len' 013/24:[down] 'iotests/308: Use conv=notrunc to test growability' 014/24:[down] 'fuse: Explicitly handle non-grow post-EOF accesses' 015/24:[----] [--] 'block: Move qemu_fcntl_addfl() into osdep.c' 016/24:[0718] [FC] 'fuse: Manually process requests (without libfuse)' 017/24:[----] [-C] 'fuse: Reduce max read size' 018/24:[0102] [FC] 'fuse: Process requests in coroutines' 019/24:[0018] [FC] 'block/export: Add multi-threading interface' 020/24:[----] [--] 'iotests/307: Test multi-thread export interface' 021/24:[down] 'fuse: Make shared export state atomic' 022/24:[0084] [FC] 'fuse: Implement multi-threading' 023/24:[----] [--] 'qapi/block-export: Document FUSE's multi-threading' 024/24:[----] [--] 'iotests/308: Add multi-threading sanity test' Hanna Czenczek (24): fuse: Copy write buffer content before polling fuse: Ensure init clean-up even with error_fatal fuse: Remove superfluous empty line fuse: Explicitly set inode ID to 1 fuse: Change setup_... to mount_fuse_export() fuse: Destroy session on mount_fuse_export() fail fuse: Fix mount options fuse: Set direct_io and parallel_direct_writes fuse: Introduce fuse_{at,de}tach_handlers() fuse: Introduce fuse_{inc,dec}_in_flight() fuse: Add halted flag fuse: fuse_{read,write}: Rename length to blk_len iotests/308: Use conv=notrunc to test growability fuse: Explicitly handle non-grow post-EOF accesses block: Move qemu_fcntl_addfl() into osdep.c fuse: Manually process requests (without libfuse) fuse: Reduce max read size fuse: Process requests in coroutines block/export: Add multi-threading interface iotests/307: Test multi-thread export interface fuse: Make shared export state atomic fuse: Implement multi-threading qapi/block-export: Document FUSE's multi-threading iotests/308: Add multi-threading sanity test qapi/block-export.json | 41 +- include/block/export.h | 12 +- include/qemu/osdep.h | 1 + block/export/export.c | 48 +- block/export/fuse.c | 1278 ++++++++++++++++++++------ block/export/vduse-blk.c | 7 + block/export/vhost-user-blk-server.c | 8 + block/file-posix.c | 17 +- nbd/server.c | 6 + util/osdep.c | 18 + tests/qemu-iotests/307 | 47 + tests/qemu-iotests/307.out | 18 + tests/qemu-iotests/308 | 95 +- tests/qemu-iotests/308.out | 71 +- 14 files changed, 1358 insertions(+), 309 deletions(-) -- 2.53.0
