On 01.10.2016 17:46, Max Reitz wrote:
On 30.09.2016 12:53, Vladimir Sementsov-Ogievskiy wrote:
Add dirty bitmap extension as specified in docs/specs/qcow2.txt.
For now, just mirror extension header into Qcow2 state and check
constraints.
For now, disable image resize if it has bitmaps. It will be fixed later.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsement...@virtuozzo.com>
---
block/qcow2.c | 83 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
block/qcow2.h | 4 +++
2 files changed, 87 insertions(+)
diff --git a/block/qcow2.c b/block/qcow2.c
index c079aa8..08c4ef9 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
[...]
@@ -162,6 +164,62 @@ static int qcow2_read_extensions(BlockDriverState *bs,
uint64_t start_offset,
}
break;
+ case QCOW2_EXT_MAGIC_DIRTY_BITMAPS:
+ ret = bdrv_pread(bs->file, offset, &bitmaps_ext, ext.len);
Overflows with ext.len > sizeof(bitmaps_ext).
(ext.len < sizeof(bitmaps_ext) is also wrong, but less dramatically so.)
+ if (ret < 0) {
+ error_setg_errno(errp, -ret, "ERROR: bitmaps_ext: "
+ "Could not read ext header");
+ return ret;
+ }
+
+ if (bitmaps_ext.reserved32 != 0) {
+ error_setg_errno(errp, -ret, "ERROR: bitmaps_ext: "
+ "Reserved field is not zero.");
Please drop the full stop at the end.
what do you mean? goto to fail: here? or not stop at all, just print error?
+ return -EINVAL;
+ }
+
+ be32_to_cpus(&bitmaps_ext.nb_bitmaps);
+ be64_to_cpus(&bitmaps_ext.bitmap_directory_size);
+ be64_to_cpus(&bitmaps_ext.bitmap_directory_offset);
+
+ if (bitmaps_ext.nb_bitmaps > QCOW_MAX_DIRTY_BITMAPS) {
+ error_setg(errp, "ERROR: bitmaps_ext: "
+ "too many dirty bitmaps");
+ return -EINVAL;
+ }
+
+ if (bitmaps_ext.nb_bitmaps == 0) {
+ error_setg(errp, "ERROR: bitmaps_ext: "
+ "found bitmaps extension with zero bitmaps");
+ return -EINVAL;
+ }
+
+ if (bitmaps_ext.bitmap_directory_offset & (s->cluster_size - 1)) {
+ error_setg(errp, "ERROR: bitmaps_ext: "
+ "wrong dirty bitmap directory offset");
s/wrong/invalid/
+ return -EINVAL;
+ }
+
+ if (bitmaps_ext.bitmap_directory_size >
+ QCOW_MAX_DIRTY_BITMAP_DIRECTORY_SIZE) {
+ error_setg(errp, "ERROR: bitmaps_ext: "
+ "too large dirty bitmap directory");
+ return -EINVAL;
+ }
+
+ s->nb_bitmaps = bitmaps_ext.nb_bitmaps;
+ s->bitmap_directory_offset =
+ bitmaps_ext.bitmap_directory_offset;
+ s->bitmap_directory_size =
+ bitmaps_ext.bitmap_directory_size;
+
+#ifdef DEBUG_EXT
+ printf("Qcow2: Got dirty bitmaps extension:"
+ " offset=%" PRIu64 " nb_bitmaps=%" PRIu32 "\n",
+ s->bitmap_directory_offset, s->nb_bitmaps);
+#endif
+ break;
+
default:
/* unknown magic - save it in case we need to rewrite the header
*/
{
[...]
@@ -2509,6 +2585,13 @@ static int qcow2_truncate(BlockDriverState *bs, int64_t
offset)
return -ENOTSUP;
}
+ /* cannot proceed if image has bitmaps */
+ if (s->nb_bitmaps) {
+ /* FIXME */
I'd call it a TODO, but that's probably a matter of taste.
+ error_report("Can't resize an image which has bitmaps");
+ return -ENOTSUP;
+ }
+
/* shrinking is currently not supported */
if (offset < bs->total_sectors * 512) {
error_report("qcow2 doesn't support shrinking images yet");
Max
--
Best regards,
Vladimir