qemu-img: Avoid duplicate block device IDs

qemu-img used to use "image" as ID for all block devices. This means
that e.g. img_convert() ended up with potentially multiple source images
and one target image, all with the same ID. The next patch will catch
this and fail to open the block device.

This patch makes sure that qemu-img uses meaningful unique IDs for the
block devices it uses.
Signed-off-by: NKevin Wolf <kwolf@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>

qemu-img.c

@@ -262,7 +262,8 @@ static int print_block_option_help(const char *filename, const char *fmt)
     return 0;
 }
 
-static BlockDriverState *bdrv_new_open(const char *filename,
+static BlockDriverState *bdrv_new_open(const char *id,
+                                       const char *filename,
                                        const char *fmt,
                                        int flags,
                                        bool require_io,
@@ -274,7 +275,7 @@ static BlockDriverState *bdrv_new_open(const char *filename,
     Error *local_err = NULL;
     int ret;
 
-    bs = bdrv_new("image", &error_abort);
+    bs = bdrv_new(id, &error_abort);
 
     if (fmt) {
         drv = bdrv_find_format(fmt);
@@ -615,7 +616,7 @@ static int img_check(int argc, char **argv)
         return 1;
     }
 
-    bs = bdrv_new_open(filename, fmt, flags, true, quiet);
+    bs = bdrv_new_open("image", filename, fmt, flags, true, quiet);
     if (!bs) {
         return 1;
     }
@@ -724,7 +725,7 @@ static int img_commit(int argc, char **argv)
         return -1;
     }
 
-    bs = bdrv_new_open(filename, fmt, flags, true, quiet);
+    bs = bdrv_new_open("image", filename, fmt, flags, true, quiet);
     if (!bs) {
         return 1;
     }
@@ -967,14 +968,14 @@ static int img_compare(int argc, char **argv)
     /* Initialize before goto out */
     qemu_progress_init(progress, 2.0);
 
-    bs1 = bdrv_new_open(filename1, fmt1, BDRV_O_FLAGS, true, quiet);
+    bs1 = bdrv_new_open("image 1", filename1, fmt1, BDRV_O_FLAGS, true, quiet);
     if (!bs1) {
         error_report("Can't open file %s", filename1);
         ret = 2;
         goto out3;
     }
 
-    bs2 = bdrv_new_open(filename2, fmt2, BDRV_O_FLAGS, true, quiet);
+    bs2 = bdrv_new_open("image 2", filename2, fmt2, BDRV_O_FLAGS, true, quiet);
     if (!bs2) {
         error_report("Can't open file %s", filename2);
         ret = 2;
@@ -1292,8 +1293,11 @@ static int img_convert(int argc, char **argv)
 
     total_sectors = 0;
     for (bs_i = 0; bs_i < bs_n; bs_i++) {
-        bs[bs_i] = bdrv_new_open(argv[optind + bs_i], fmt, BDRV_O_FLAGS, true,
-                                 quiet);
+        char *id = bs_n > 1 ? g_strdup_printf("source %d", bs_i)
+                            : g_strdup("source");
+        bs[bs_i] = bdrv_new_open(id, argv[optind + bs_i], fmt, BDRV_O_FLAGS,
+                                 true, quiet);
+        g_free(id);
         if (!bs[bs_i]) {
             error_report("Could not open '%s'", argv[optind + bs_i]);
             ret = -1;
@@ -1416,7 +1420,7 @@ static int img_convert(int argc, char **argv)
         return -1;
     }
 
-    out_bs = bdrv_new_open(out_filename, out_fmt, flags, true, quiet);
+    out_bs = bdrv_new_open("target", out_filename, out_fmt, flags, true, quiet);
     if (!out_bs) {
         ret = -1;
         goto out;
@@ -1799,8 +1803,8 @@ static ImageInfoList *collect_image_info_list(const char *filename,
         }
         g_hash_table_insert(filenames, (gpointer)filename, NULL);
 
-        bs = bdrv_new_open(filename, fmt, BDRV_O_FLAGS | BDRV_O_NO_BACKING,
-                           false, false);
+        bs = bdrv_new_open("image", filename, fmt,
+                           BDRV_O_FLAGS | BDRV_O_NO_BACKING, false, false);
         if (!bs) {
             goto err;
         }
@@ -2060,7 +2064,7 @@ static int img_map(int argc, char **argv)
         return 1;
     }
 
-    bs = bdrv_new_open(filename, fmt, BDRV_O_FLAGS, true, false);
+    bs = bdrv_new_open("image", filename, fmt, BDRV_O_FLAGS, true, false);
     if (!bs) {
         return 1;
     }
@@ -2180,7 +2184,7 @@ static int img_snapshot(int argc, char **argv)
     filename = argv[optind++];
 
     /* Open the image */
-    bs = bdrv_new_open(filename, NULL, bdrv_oflags, true, quiet);
+    bs = bdrv_new_open("image", filename, NULL, bdrv_oflags, true, quiet);
     if (!bs) {
         return 1;
     }
@@ -2309,7 +2313,7 @@ static int img_rebase(int argc, char **argv)
      * Ignore the old backing file for unsafe rebase in case we want to correct
      * the reference to a renamed or moved backing file.
      */
-    bs = bdrv_new_open(filename, fmt, flags, true, quiet);
+    bs = bdrv_new_open("image", filename, fmt, flags, true, quiet);
     if (!bs) {
         return 1;
     }
@@ -2606,7 +2610,8 @@ static int img_resize(int argc, char **argv)
     n = qemu_opt_get_size(param, BLOCK_OPT_SIZE, 0);
     qemu_opts_del(param);
 
-    bs = bdrv_new_open(filename, fmt, BDRV_O_FLAGS | BDRV_O_RDWR, true, quiet);
+    bs = bdrv_new_open("image", filename, fmt, BDRV_O_FLAGS | BDRV_O_RDWR,
+                       true, quiet);
     if (!bs) {
         ret = -1;
         goto out;
@@ -2707,7 +2712,8 @@ static int img_amend(int argc, char **argv)
         help();
     }
 
-    bs = bdrv_new_open(filename, fmt, BDRV_O_FLAGS | BDRV_O_RDWR, true, quiet);
+    bs = bdrv_new_open("image", filename, fmt,
+                       BDRV_O_FLAGS | BDRV_O_RDWR, true, quiet);
     if (!bs) {
         error_report("Could not open image '%s'", filename);
         ret = -1;