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authorMarkus Armbruster <armbru@redhat.com>2020-12-17 17:19:56 +0100
committerKevin Wolf <kwolf@redhat.com>2020-12-18 12:43:06 +0100
commitb0ce8cb0e8470b37963d1db7e4baca9c3647b0a1 (patch)
tree7a282e71e1cbfa32cc1fe0edcaa9ac03edebc576 /block
parent02df95c4a1746aac168dc70a6d8aec062e3f6250 (diff)
block/vpc: Don't abuse the footer buffer as BAT sector buffer
create_dynamic_disk() takes a buffer holding the footer as first argument. It writes out the footer (512 bytes), then reuses the buffer to initialize and write out the dynamic header (1024 bytes), then reuses it again to initialize and write out BAT sectors (512). Works, because the caller passes a buffer that is large enough for all three purposes. I hate that. Use a separate buffer for writing out BAT sectors. The next commit will do the same for the dynamic header. Signed-off-by: Markus Armbruster <armbru@redhat.com> Message-Id: <20201217162003.1102738-3-armbru@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Diffstat (limited to 'block')
-rw-r--r--block/vpc.c5
1 files changed, 3 insertions, 2 deletions
diff --git a/block/vpc.c b/block/vpc.c
index 2fcf3f6283..d18ecc3da1 100644
--- a/block/vpc.c
+++ b/block/vpc.c
@@ -824,6 +824,7 @@ static int create_dynamic_disk(BlockBackend *blk, uint8_t *buf,
{
VHDDynDiskHeader *dyndisk_header =
(VHDDynDiskHeader *) buf;
+ uint8_t bat_sector[512];
size_t block_size, num_bat_entries;
int i;
int ret;
@@ -847,9 +848,9 @@ static int create_dynamic_disk(BlockBackend *blk, uint8_t *buf,
/* Write the initial BAT */
offset = 3 * 512;
- memset(buf, 0xFF, 512);
+ memset(bat_sector, 0xFF, 512);
for (i = 0; i < DIV_ROUND_UP(num_bat_entries * 4, 512); i++) {
- ret = blk_pwrite(blk, offset, buf, 512, 0);
+ ret = blk_pwrite(blk, offset, bat_sector, 512, 0);
if (ret < 0) {
goto fail;
}