block/rbd: enable filename option and parsing

When enabling option parsing and blockdev-add for rbd, we removed the
'filename' option.  Unfortunately, this was a bit optimistic, as
previous versions of QEMU allowed the use of the option in backing
filenames via json.  This means that without parsing this option, we
cannot open existing images that used to work fine.

See bug: https://bugzilla.redhat.com/show_bug.cgi?id=1457088Tested-by: NRichard W.M. Jones <rjones@redhat.com>
Signed-off-by: NJeff Cody <jcody@redhat.com>
Message-id: 937dc9fde348d13311eb8e23444df3bc3190b612.1497444637.git.jcody@redhat.com
Signed-off-by: NJeff Cody <jcody@redhat.com>

block/rbd.c

@@ -340,6 +340,10 @@ static QemuOptsList runtime_opts = {
             .type = QEMU_OPT_STRING,
             .help = "Legacy rados key/value option parameters",
         },
+        {
+            .name = "filename",
+            .type = QEMU_OPT_STRING,
+        },
         { /* end of list */ }
     },
 };
@@ -541,12 +545,27 @@ static int qemu_rbd_open(BlockDriverState *bs, QDict *options, int flags,
 {
     BDRVRBDState *s = bs->opaque;
     const char *pool, *snap, *conf, *user, *image_name, *keypairs;
-    const char *secretid;
+    const char *secretid, *filename;
     QemuOpts *opts;
     Error *local_err = NULL;
     char *mon_host = NULL;
     int r;
 
+    /* If we are given a filename, parse the filename, with precedence given to
+     * filename encoded options */
+    filename = qdict_get_try_str(options, "filename");
+    if (filename) {
+        error_report("Warning: 'filename' option specified. "
+                      "This is an unsupported option, and may be deprecated "
+                      "in the future");
+        qemu_rbd_parse_filename(filename, options, &local_err);
+        if (local_err) {
+            r = -EINVAL;
+            error_propagate(errp, local_err);
+            goto exit;
+        }
+    }
+
     opts = qemu_opts_create(&runtime_opts, NULL, 0, &error_abort);
     qemu_opts_absorb_qdict(opts, options, &local_err);
     if (local_err) {
@@ -665,6 +684,7 @@ failed_shutdown:
 failed_opts:
     qemu_opts_del(opts);
     g_free(mon_host);
+exit:
     return r;
 }