When open the vpc snapshot based FIXED format, its backing file,
this FIXED vpc image, could be probed as a raw image, because that
the find_image_format just checkout the first sector.
Add a re-probe for the last sector to FIXED base vpc image,when get
a NULL or raw driver in first sector probe.
Signed-off-by: Xiaodong Gong <gongxiaodo...@huawei.com>
---
block.c | 55 ++++++++++++++++++++++++++++++++++++++++++++++++-------
1 file changed, 48 insertions(+), 7 deletions(-)
diff --git a/block.c b/block.c
index d45e4dd..e183515 100644
--- a/block.c
+++ b/block.c
@@ -702,20 +702,24 @@ BlockDriver *bdrv_probe_all(const uint8_t *buf, int
buf_size,
return drv;
}
-static int find_image_format(BlockDriverState *bs, const char *filename,
- BlockDriver **pdrv, Error **errp)
+static int probe_image_format(BlockDriverState *bs, const char *filename,
+ int64_t offset, BlockDriver **pdrv, Error **errp,
+ bool isfoot)
{
BlockDriver *drv;
uint8_t buf[BLOCK_PROBE_BUF_SIZE];
int ret = 0;
- /* Return the raw BlockDriver * to scsi-generic devices or empty drives */
- if (bs->sg || !bdrv_is_inserted(bs) || bdrv_getlength(bs) == 0) {
- *pdrv = &bdrv_raw;
+ if (!bs || !filename) {
+ *pdrv = NULL;
return ret;
}
- ret = bdrv_pread(bs, 0, buf, sizeof(buf));
+ if (offset + sizeof(buf) > bs->total_sectors << BDRV_SECTOR_BITS) {
+ return ret;
+ }
+
+ ret = bdrv_pread(bs, offset, buf, sizeof(buf));
if (ret < 0) {
error_setg_errno(errp, -ret, "Could not read image for determining its
"
"format");
@@ -724,12 +728,49 @@ static int find_image_format(BlockDriverState *bs, const
char *filename,
}
drv = bdrv_probe_all(buf, ret, filename);
- if (!drv) {
+ if (!drv && isfoot) {
error_setg(errp, "Could not determine image format: No compatible "
"driver found");
ret = -ENOENT;
}
*pdrv = drv;
+
+ return ret;
+}
+
+static int find_image_format(BlockDriverState *bs, const char *filename,
+ BlockDriver **pdrv, Error **errp)
+{
+ int last_sector_offset;
+ int ret = 0;
+
+ *pdrv = NULL;
+
+ /* Return the raw BlockDriver * to scsi-generic devices or empty drives */
+ if (bs->sg || !bdrv_is_inserted(bs) || bdrv_getlength(bs) == 0) {
+ *pdrv = &bdrv_raw;
+ return ret;
+ }
+
+ /* probe the header to guess image format */
+ ret = probe_image_format(bs, filename, 0, pdrv, errp, false);
+ if (ret < 0) {
+ return ret;
+ }
+
+ /* The FIXED base img of VHD only has the footer in tail. The drv could
+ * be NULL or raw */
+ if (*pdrv && *pdrv != &bdrv_raw) {
+ return ret;
+ }
+
+ last_sector_offset = (bs->total_sectors - 1) << BDRV_SECTOR_BITS;
+ ret = probe_image_format(bs, filename, last_sector_offset, pdrv,
+ errp, true);
+ if (ret < 0) {
+ return ret;
+ }
+
return ret;
}
--
1.8.3.1
