qemu-img rebase: Fix output image corruption

PATCH New Kevin Wolf 1 participant 1 message Apr 29, 2010

Share & tools

Kevin Wolf

author

2010-04-29 12:57 UTC #0 lore raw

PATCH 1/1 qemu-img rebase: Fix output image corruption

qemu-img rebase must always give clusters in the COW file priority over those in the backing file. As it failed to use number of non-allocated clusters but assumed the maximum, it was possible that allocated clusters were taken from the backing file instead, leading to a corrupted output image.

Signed-off-by Kevin Wolf <[email protected]>

---
 qemu-img.c |    6 +++---
 1 files changed, 3 insertions(+), 3 deletions(-)

qemu-img.c +3 -3

index c21d999..d3c30a7 100644
@@ -1136,7 +1136,7 @@ static int img_rebase(int argc, char **argv)
     if (!unsafe) {
         uint64_t num_sectors;
         uint64_t sector;
-        int n, n1;
+        int n;
         uint8_t * buf_old;
         uint8_t * buf_new;

@@ -1155,8 +1155,8 @@ static int img_rebase(int argc, char **argv)
             }
 
             /* If the cluster is allocated, we don't need to take action */
-            if (bdrv_is_allocated(bs, sector, n, &n1)) {
-                n = n1;
+            ret = bdrv_is_allocated(bs, sector, n, &n);
+            if (ret) {
                 continue;
             }

Signature · 1 line

1.6.6.1