From: "Dr. David Alan Gilbert" <dgilb...@redhat.com> Add a wrapper to send VHOST_USER_SLAVE_FS_IO commands and a further wrapper for sending a fuse_buf write using the FS_IO slave command.
Signed-off-by: Dr. David Alan Gilbert <dgilb...@redhat.com> Reviewed-by: Stefan Hajnoczi <stefa...@redhat.com> --- tools/virtiofsd/fuse_lowlevel.h | 25 +++++++++++++++++++ tools/virtiofsd/fuse_virtio.c | 43 +++++++++++++++++++++++++++++++++ 2 files changed, 68 insertions(+) diff --git a/tools/virtiofsd/fuse_lowlevel.h b/tools/virtiofsd/fuse_lowlevel.h index 27b07bfc22..757cdae49b 100644 --- a/tools/virtiofsd/fuse_lowlevel.h +++ b/tools/virtiofsd/fuse_lowlevel.h @@ -2013,4 +2013,29 @@ int64_t fuse_virtio_map(fuse_req_t req, VhostUserFSSlaveMsg *msg, int fd); */ int64_t fuse_virtio_unmap(struct fuse_session *se, VhostUserFSSlaveMsg *msg); +/** + * For use with virtio-fs; request IO directly to memory + * + * @param se The current session + * @param msg A set of IO requests + * @param fd The fd to map + * @return Length on success, negative errno on error + */ +int64_t fuse_virtio_io(struct fuse_session *se, VhostUserFSSlaveMsg *msg, + int fd); + +/** + * For use with virtio-fs; wrapper for fuse_virtio_io for writes + * from memory to an fd + * @param req The request that triggered this action + * @param dst The destination (file) memory buffer + * @param dst_off Byte offset in the file + * @param src The source (memory) buffer + * @param src_off The GPA + * @param len Length in bytes + */ +ssize_t fuse_virtio_write(fuse_req_t req, const struct fuse_buf *dst, + size_t dst_off, const struct fuse_buf *src, + size_t src_off, size_t len); + #endif /* FUSE_LOWLEVEL_H_ */ diff --git a/tools/virtiofsd/fuse_virtio.c b/tools/virtiofsd/fuse_virtio.c index 85d90ca595..402e94dde6 100644 --- a/tools/virtiofsd/fuse_virtio.c +++ b/tools/virtiofsd/fuse_virtio.c @@ -1141,3 +1141,46 @@ int64_t fuse_virtio_unmap(struct fuse_session *se, VhostUserFSSlaveMsg *msg) return vu_fs_cache_request(&se->virtio_dev->dev, VHOST_USER_SLAVE_FS_UNMAP, -1, msg); } + +int64_t fuse_virtio_io(struct fuse_session *se, VhostUserFSSlaveMsg *msg, + int fd) +{ + if (!se->virtio_dev) { + return -ENODEV; + } + return vu_fs_cache_request(&se->virtio_dev->dev, VHOST_USER_SLAVE_FS_IO, + fd, msg); +} + +/* + * Write to a file (dst) from an area of guest GPA (src) that probably + * isn't visible to the daemon. + */ +ssize_t fuse_virtio_write(fuse_req_t req, const struct fuse_buf *dst, + size_t dst_off, const struct fuse_buf *src, + size_t src_off, size_t len) +{ + VhostUserFSSlaveMsg *msg = g_malloc0(sizeof(VhostUserFSSlaveMsg) + + sizeof(VhostUserFSSlaveMsgEntry)); + + msg->count = 1; + + if (dst->flags & FUSE_BUF_FD_SEEK) { + msg->entries[0].fd_offset = dst->pos + dst_off; + } else { + off_t cur = lseek(dst->fd, 0, SEEK_CUR); + if (cur == (off_t)-1) { + g_free(msg); + return -errno; + } + msg->entries[0].fd_offset = cur; + } + msg->entries[0].c_offset = (uintptr_t)src->mem + src_off; + msg->entries[0].len = len; + msg->entries[0].flags = VHOST_USER_FS_FLAG_MAP_W; + + int64_t result = fuse_virtio_io(req->se, msg, dst->fd); + fuse_log(FUSE_LOG_DEBUG, "%s: result=%ld\n", __func__, result); + g_free(msg); + return result; +} -- 2.31.1