[v3,14/26] DAX: virtiofsd: Wire up passthrough_ll's lo_setupmapping

Commit Message

Dr. David Alan Gilbert April 28, 2021, 11 a.m. UTC

From: "Dr. David Alan Gilbert" <[e-mail]>

Wire up passthrough_ll's setupmapping to allocate, send to virtio
and then reply OK.

Guest might not pass file pointer. In that case using inode info, open
the file again, mmap() and close fd.

Signed-off-by: Dr. David Alan Gilbert <[e-mail]>
Signed-off-by: Vivek Goyal <[e-mail]>
With fix from:
Signed-off-by: Fotis Xenakis <[e-mail]>
Reviewed-by: Stefan Hajnoczi <[e-mail]>
---
 tools/virtiofsd/fuse_lowlevel.c  | 13 ++++++--
 tools/virtiofsd/passthrough_ll.c | 57 ++++++++++++++++++++++++++++++--
 2 files changed, 66 insertions(+), 4 deletions(-)

Patch

diff --git a/tools/virtiofsd/fuse_lowlevel.c b/tools/virtiofsd/fuse_lowlevel.c
index a1a8730b73..4921f1bbb7 100644
--- a/tools/virtiofsd/fuse_lowlevel.c
+++ b/tools/virtiofsd/fuse_lowlevel.c
@@ -1899,8 +1899,17 @@  static void do_setupmapping(fuse_req_t req, fuse_ino_t nodeid,
     }
 
     if (req->se->op.setupmapping) {
-        req->se->op.setupmapping(req, nodeid, arg->foffset, arg->len,
-                                 arg->moffset, genflags, &fi);
+        /*
+         * TODO: Add a flag to request which tells if arg->fh is
+         * valid or not.
+         */
+        if (fi.fh == (uint64_t)-1) {
+            req->se->op.setupmapping(req, nodeid, arg->foffset, arg->len,
+                                     arg->moffset, genflags, NULL);
+        } else {
+            req->se->op.setupmapping(req, nodeid, arg->foffset, arg->len,
+                                     arg->moffset, genflags, &fi);
+        }
     } else {
         fuse_reply_err(req, ENOSYS);
     }
diff --git a/tools/virtiofsd/passthrough_ll.c b/tools/virtiofsd/passthrough_ll.c
index a16d425b78..6981737389 100644
--- a/tools/virtiofsd/passthrough_ll.c
+++ b/tools/virtiofsd/passthrough_ll.c
@@ -3149,8 +3149,61 @@  static void lo_setupmapping(fuse_req_t req, fuse_ino_t ino, uint64_t foffset,
                             uint64_t len, uint64_t moffset, uint64_t flags,
                             struct fuse_file_info *fi)
 {
-    /* TODO */
-    fuse_reply_err(req, ENOSYS);
+    struct lo_data *lo = lo_data(req);
+    int ret = 0, fd;
+    VhostUserFSSlaveMsg *msg = g_malloc0(sizeof(VhostUserFSSlaveMsg) +
+                                         sizeof(VhostUserFSSlaveMsgEntry));
+    uint64_t vhu_flags;
+    char *buf;
+    bool writable = flags & O_RDWR;
+
+    fuse_log(FUSE_LOG_DEBUG,
+             "lo_setupmapping(ino=%" PRIu64 ", fi=0x%p,"
+             " foffset=%" PRIu64 ", len=%" PRIu64 ", moffset=%" PRIu64
+             ", flags=%" PRIu64 ")\n",
+             ino, (void *)fi, foffset, len, moffset, flags);
+
+    vhu_flags = VHOST_USER_FS_FLAG_MAP_R;
+    if (writable) {
+        vhu_flags |= VHOST_USER_FS_FLAG_MAP_W;
+    }
+
+    msg->count = 1;
+    msg->entries[0].fd_offset = foffset;
+    msg->entries[0].len = len;
+    msg->entries[0].c_offset = moffset;
+    msg->entries[0].flags = vhu_flags;
+
+    if (fi) {
+        fd = lo_fi_fd(req, fi);
+    } else {
+        ret = asprintf(&buf, "%i", lo_fd(req, ino));
+        if (ret == -1) {
+            g_free(msg);
+            return (void)fuse_reply_err(req, errno);
+        }
+
+        fd = openat(lo->proc_self_fd, buf, flags);
+        free(buf);
+        if (fd == -1) {
+            g_free(msg);
+            return (void)fuse_reply_err(req, errno);
+        }
+    }
+
+    ret = fuse_virtio_map(req, msg, fd);
+    if (ret < 0) {
+        fuse_log(FUSE_LOG_ERR,
+                 "%s: map over virtio failed (ino=%" PRId64
+                 "fd=%d moffset=0x%" PRIx64 "). err = %d\n",
+                 __func__, ino, fd, moffset, ret);
+    }
+
+    if (!fi) {
+        close(fd);
+    }
+    fuse_reply_err(req, -ret);
+    g_free(msg);
 }
 
 static void lo_removemapping(fuse_req_t req, struct fuse_session *se,