Re: [RFC PATCH 1/4] block/vdi: When writing new bmap entry fails, don't leak the buffer

[Philippe Mathieu-Daudé]

On 3/9/21 11:21 AM, David Edmondson wrote:
> If a new bitmap entry is allocated, requiring the entire block to be
> written, avoiding leaking the buffer allocated for the block should
> the write fail.
> 
> Signed-off-by: David Edmondson <david.edmondson@oracle.com>

Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>

> ---
>  block/vdi.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/block/vdi.c b/block/vdi.c
> index 5627e7d764..2a6dc26124 100644
> --- a/block/vdi.c
> +++ b/block/vdi.c
> @@ -690,6 +690,7 @@ nonallocating_write:
>  
>      logout("finished data write\n");
>      if (ret < 0) {
> +        g_free(block);
>          return ret;
>      }

Alternative using g_autofree:

-- >8 --
diff --git a/block/vdi.c b/block/vdi.c
index 5627e7d764a..1cd8ae2ba99 100644
--- a/block/vdi.c
+++ b/block/vdi.c
@@ -612,7 +612,7 @@ vdi_co_pwritev(BlockDriverState *bs, uint64_t
offset, uint64_t bytes,
     uint64_t data_offset;
     uint32_t bmap_first = VDI_UNALLOCATED;
     uint32_t bmap_last = VDI_UNALLOCATED;
-    uint8_t *block = NULL;
+    g_autofree uint8_t *block = NULL;
     uint64_t bytes_done = 0;
     int ret = 0;

@@ -705,9 +705,6 @@ nonallocating_write:
         *header = s->header;
         vdi_header_to_le(header);
         ret = bdrv_pwrite(bs->file, 0, block, sizeof(VdiHeader));
-        g_free(block);
-        block = NULL;
-
         if (ret < 0) {
             return ret;
         }
---