vmdk: Reject excess extents in blockdev-create

Clarify that the number of extents provided in BlockdevCreateOptionsVmdk
must match the number of extents that will actually be used. Providing
more extents will result in an error now.

This requires adapting the test case to provide the right number of
extents.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>

1 files changed, 24 insertions, 5 deletions

diff --git a/block/vmdk.c b/block/vmdk.c
index 5a162ee85c..682ad93aa1 100644
--- a/block/vmdk.c
+++ b/block/vmdk.c
@@ -1970,6 +1970,7 @@ static int coroutine_fn vmdk_co_do_create(int64_t size,
 {
     int extent_idx;
     BlockBackend *blk = NULL;
+    BlockBackend *extent_blk;
     Error *local_err = NULL;
     char *desc = NULL;
     int ret = 0;
@@ -2107,7 +2108,6 @@ static int coroutine_fn vmdk_co_do_create(int64_t size,
     }
     extent_idx = 1;
     while (created_size < size) {
-        BlockBackend *extent_blk;
         int64_t cur_size = MIN(size - created_size, extent_size);
         extent_blk = extent_fn(cur_size, extent_idx, flat, split, compress,
                                zeroed_grain, opaque, errp);
@@ -2121,6 +2121,17 @@ static int coroutine_fn vmdk_co_do_create(int64_t size,
         extent_idx++;
         blk_unref(extent_blk);
     }
+
+    /* Check whether we got excess extents */
+    extent_blk = extent_fn(-1, extent_idx, flat, split, compress, zeroed_grain,
+                           opaque, NULL);
+    if (extent_blk) {
+        blk_unref(extent_blk);
+        error_setg(errp, "List of extents contains unused extents");
+        ret = -EINVAL;
+        goto exit;
+    }
+
     /* generate descriptor file */
     desc = g_strdup_printf(desc_template,
                            g_random_int(),
@@ -2181,6 +2192,12 @@ static BlockBackend *vmdk_co_create_opts_cb(int64_t size, int idx,
     char *ext_filename = NULL;
     char *rel_filename = NULL;
 
+    /* We're done, don't create excess extents. */
+    if (size == -1) {
+        assert(errp == NULL);
+        return NULL;
+    }
+
     if (idx == 0) {
         rel_filename = g_strdup_printf("%s%s", data->prefix, data->postfix);
     } else if (split) {
@@ -2342,10 +2359,12 @@ static BlockBackend *vmdk_co_create_cb(int64_t size, int idx,
     blk_set_allow_write_beyond_eof(blk, true);
     bdrv_unref(bs);
 
-    ret = vmdk_init_extent(blk, size, flat, compress, zeroed_grain, errp);
-    if (ret) {
-        blk_unref(blk);
-        blk = NULL;
+    if (size != -1) {
+        ret = vmdk_init_extent(blk, size, flat, compress, zeroed_grain, errp);
+        if (ret) {
+            blk_unref(blk);
+            blk = NULL;
+        }
     }
     return blk;
 }