qemu-io: Add command 'reopen'

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>

qemu-io-cmds.c

@@ -1979,6 +1979,95 @@ static const cmdinfo_t map_cmd = {
        .oneline        = "prints the allocated areas of a file",
 };
 
+static void reopen_help(void)
+{
+    printf(
+"\n"
+" Changes the open options of an already opened image\n"
+"\n"
+" Example:\n"
+" 'reopen -o lazy-refcounts=on' - activates lazy refcount writeback on a qcow2 image\n"
+"\n"
+" -r, -- Reopen the image read-only\n"
+" -c, -- Change the cache mode to the given value\n"
+" -o, -- Changes block driver options (cf. 'open' command)\n"
+"\n");
+}
+
+static int reopen_f(BlockBackend *blk, int argc, char **argv);
+
+static QemuOptsList reopen_opts = {
+    .name = "reopen",
+    .merge_lists = true,
+    .head = QTAILQ_HEAD_INITIALIZER(reopen_opts.head),
+    .desc = {
+        /* no elements => accept any params */
+        { /* end of list */ }
+    },
+};
+
+static const cmdinfo_t reopen_cmd = {
+       .name           = "reopen",
+       .argmin         = 0,
+       .argmax         = -1,
+       .cfunc          = reopen_f,
+       .args           = "[-r] [-c cache] [-o options]",
+       .oneline        = "reopens an image with new options",
+       .help           = reopen_help,
+};
+
+static int reopen_f(BlockBackend *blk, int argc, char **argv)
+{
+    BlockDriverState *bs = blk_bs(blk);
+    QemuOpts *qopts;
+    QDict *opts;
+    int c;
+    int flags = bs->open_flags;
+
+    BlockReopenQueue *brq;
+    Error *local_err = NULL;
+
+    while ((c = getopt(argc, argv, "c:o:r")) != -1) {
+        switch (c) {
+        case 'c':
+            if (bdrv_parse_cache_flags(optarg, &flags) < 0) {
+                error_report("Invalid cache option: %s", optarg);
+                return 0;
+            }
+            break;
+        case 'o':
+            if (!qemu_opts_parse_noisily(&reopen_opts, optarg, 0)) {
+                qemu_opts_reset(&reopen_opts);
+                return 0;
+            }
+            break;
+        case 'r':
+            flags &= ~BDRV_O_RDWR;
+            break;
+        default:
+            qemu_opts_reset(&reopen_opts);
+            return qemuio_command_usage(&reopen_cmd);
+        }
+    }
+
+    if (optind != argc) {
+        qemu_opts_reset(&reopen_opts);
+        return qemuio_command_usage(&reopen_cmd);
+    }
+
+    qopts = qemu_opts_find(&reopen_opts, NULL);
+    opts = qopts ? qemu_opts_to_qdict(qopts, NULL) : NULL;
+    qemu_opts_reset(&reopen_opts);
+
+    brq = bdrv_reopen_queue(NULL, bs, opts, flags);
+    bdrv_reopen_multiple(brq, &local_err);
+    if (local_err) {
+        error_report_err(local_err);
+    }
+
+    return 0;
+}
+
 static int break_f(BlockBackend *blk, int argc, char **argv)
 {
     int ret;
@@ -2266,6 +2355,7 @@ static void __attribute((constructor)) init_qemuio_commands(void)
     qemuio_add_command(&discard_cmd);
     qemuio_add_command(&alloc_cmd);
     qemuio_add_command(&map_cmd);
+    qemuio_add_command(&reopen_cmd);
     qemuio_add_command(&break_cmd);
     qemuio_add_command(&remove_break_cmd);
     qemuio_add_command(&resume_cmd);