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>
---
tools/virtiofsd/fuse_lowlevel.h | 25 ++++++++++++++++++++++
tools/virtiofsd/fuse_virtio.c | 38 +++++++++++++++++++++++++++++++++
2 files changed, 63 insertions(+)
diff --git a/tools/virtiofsd/fuse_lowlevel.h b/tools/virtiofsd/fuse_lowlevel.h
index 53439f5432..af928b262f 100644
--- a/tools/virtiofsd/fuse_lowlevel.h
+++ b/tools/virtiofsd/fuse_lowlevel.h
@@ -2012,4 +2012,29 @@ 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 f217a093c8..8feb3c0261 100644
--- a/tools/virtiofsd/fuse_virtio.c
+++ b/tools/virtiofsd/fuse_virtio.c
@@ -1062,3 +1062,41 @@ 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 = { 0 };
+
+ if (dst->flags & FUSE_BUF_FD_SEEK) {
+ msg.fd_offset[0] = dst->pos + dst_off;
+ } else {
+ off_t cur = lseek(dst->fd, 0, SEEK_CUR);
+ if (cur == (off_t)-1) {
+ return -errno;
+ }
+ msg.fd_offset[0] = cur;
+ }
+ msg.c_offset[0] = (uintptr_t)src->mem + src_off;
+ msg.len[0] = len;
+ msg.flags[0] = 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);
+ return result;
+}
--
2.29.2
