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>

4 files changed, 38 insertions, 13 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;
 }
diff --git a/qapi/block-core.json b/qapi/block-core.json
index a5924b40af..5f17d67d71 100644
--- a/qapi/block-core.json
+++ b/qapi/block-core.json
@@ -4184,7 +4184,8 @@
 #               twoGbMaxExtentSparse and twoGbMaxExtentFlat formats. For
 #               monolithicFlat, only one entry is required; for
 #               twoGbMaxExtent* formats, the number of entries required is
-#               calculated as extent_number = virtual_size / 2GB.
+#               calculated as extent_number = virtual_size / 2GB. Providing
+#               more extents than will be used is an error.
 # @subformat    The subformat of the VMDK image. Default: "monolithicSparse".
 # @backing-file The path of backing file. Default: no backing file is used.
 # @adapter-type The adapter type used to fill in the descriptor. Default: ide.
diff --git a/tests/qemu-iotests/237 b/tests/qemu-iotests/237
index e04a1ac6be..251771d7fb 100755
--- a/tests/qemu-iotests/237
+++ b/tests/qemu-iotests/237
@@ -20,6 +20,7 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #
 
+import math
 import iotests
 from iotests import imgfmt
 
@@ -222,12 +223,15 @@ with iotests.FilePath('t.vmdk') as disk_path, \
             iotests.log("= %s %d =" % (subfmt, size))
             iotests.log("")
 
+            num_extents = math.ceil(size / 2.0**31)
+            extents = [ "ext%d" % (i) for i in range(1, num_extents + 1) ]
+
             vm.launch()
             blockdev_create(vm, { 'driver': imgfmt,
                                   'file': 'node0',
                                   'size': size,
                                   'subformat': subfmt,
-                                  'extents': ['ext1', 'ext2', 'ext3'] })
+                                  'extents': extents })
             vm.shutdown()
 
             iotests.img_info_log(disk_path)
diff --git a/tests/qemu-iotests/237.out b/tests/qemu-iotests/237.out
index 1aa9aad349..241c864369 100644
--- a/tests/qemu-iotests/237.out
+++ b/tests/qemu-iotests/237.out
@@ -154,6 +154,7 @@ Job failed: Extent [0] not specified
 
 {"execute": "blockdev-create", "arguments": {"job_id": "job0", "options": {"driver": "vmdk", "extents": ["ext1", "ext2", "ext3"], "file": "node0", "size": 512, "subformat": "monolithicFlat"}}}
 {"return": {}}
+Job failed: List of extents contains unused extents
 {"execute": "job-dismiss", "arguments": {"id": "job0"}}
 {"return": {}}
 
@@ -161,7 +162,7 @@ Job failed: Extent [0] not specified
 
 = twoGbMaxExtentFlat 512 =
 
-{"execute": "blockdev-create", "arguments": {"job_id": "job0", "options": {"driver": "vmdk", "extents": ["ext1", "ext2", "ext3"], "file": "node0", "size": 512, "subformat": "twoGbMaxExtentFlat"}}}
+{"execute": "blockdev-create", "arguments": {"job_id": "job0", "options": {"driver": "vmdk", "extents": ["ext1"], "file": "node0", "size": 512, "subformat": "twoGbMaxExtentFlat"}}}
 {"return": {}}
 {"execute": "job-dismiss", "arguments": {"id": "job0"}}
 {"return": {}}
@@ -181,7 +182,7 @@ Format specific information:
 
 = twoGbMaxExtentSparse 512 =
 
-{"execute": "blockdev-create", "arguments": {"job_id": "job0", "options": {"driver": "vmdk", "extents": ["ext1", "ext2", "ext3"], "file": "node0", "size": 512, "subformat": "twoGbMaxExtentSparse"}}}
+{"execute": "blockdev-create", "arguments": {"job_id": "job0", "options": {"driver": "vmdk", "extents": ["ext1"], "file": "node0", "size": 512, "subformat": "twoGbMaxExtentSparse"}}}
 {"return": {}}
 {"execute": "job-dismiss", "arguments": {"id": "job0"}}
 {"return": {}}
@@ -203,7 +204,7 @@ Format specific information:
 
 = twoGbMaxExtentFlat 1073741824 =
 
-{"execute": "blockdev-create", "arguments": {"job_id": "job0", "options": {"driver": "vmdk", "extents": ["ext1", "ext2", "ext3"], "file": "node0", "size": 1073741824, "subformat": "twoGbMaxExtentFlat"}}}
+{"execute": "blockdev-create", "arguments": {"job_id": "job0", "options": {"driver": "vmdk", "extents": ["ext1"], "file": "node0", "size": 1073741824, "subformat": "twoGbMaxExtentFlat"}}}
 {"return": {}}
 {"execute": "job-dismiss", "arguments": {"id": "job0"}}
 {"return": {}}
@@ -223,7 +224,7 @@ Format specific information:
 
 = twoGbMaxExtentSparse 1073741824 =
 
-{"execute": "blockdev-create", "arguments": {"job_id": "job0", "options": {"driver": "vmdk", "extents": ["ext1", "ext2", "ext3"], "file": "node0", "size": 1073741824, "subformat": "twoGbMaxExtentSparse"}}}
+{"execute": "blockdev-create", "arguments": {"job_id": "job0", "options": {"driver": "vmdk", "extents": ["ext1"], "file": "node0", "size": 1073741824, "subformat": "twoGbMaxExtentSparse"}}}
 {"return": {}}
 {"execute": "job-dismiss", "arguments": {"id": "job0"}}
 {"return": {}}
@@ -245,7 +246,7 @@ Format specific information:
 
 = twoGbMaxExtentFlat 2147483648 =
 
-{"execute": "blockdev-create", "arguments": {"job_id": "job0", "options": {"driver": "vmdk", "extents": ["ext1", "ext2", "ext3"], "file": "node0", "size": 2147483648, "subformat": "twoGbMaxExtentFlat"}}}
+{"execute": "blockdev-create", "arguments": {"job_id": "job0", "options": {"driver": "vmdk", "extents": ["ext1"], "file": "node0", "size": 2147483648, "subformat": "twoGbMaxExtentFlat"}}}
 {"return": {}}
 {"execute": "job-dismiss", "arguments": {"id": "job0"}}
 {"return": {}}
@@ -265,7 +266,7 @@ Format specific information:
 
 = twoGbMaxExtentSparse 2147483648 =
 
-{"execute": "blockdev-create", "arguments": {"job_id": "job0", "options": {"driver": "vmdk", "extents": ["ext1", "ext2", "ext3"], "file": "node0", "size": 2147483648, "subformat": "twoGbMaxExtentSparse"}}}
+{"execute": "blockdev-create", "arguments": {"job_id": "job0", "options": {"driver": "vmdk", "extents": ["ext1"], "file": "node0", "size": 2147483648, "subformat": "twoGbMaxExtentSparse"}}}
 {"return": {}}
 {"execute": "job-dismiss", "arguments": {"id": "job0"}}
 {"return": {}}