[PATCH 1/6] parallels: Incorrect data end calculation in parallels_open()

[Alexander Ivanov]

The BDRVParallelsState structure contains data_end field that
is measured in sectors.
In parallels_open() initially this field is set by data_off field from
parallels image header.

According to the parallels format documentation,
data_off field contains an offset, in sectors, from the start of the file
to the start of the data area.
For "WithoutFreeSpace" images: if data_off is zero,
the offset is calculated as the end of the BAT table
plus some padding to ensure sector size alignment.

The parallels_open() function has code for handling zero value
in data_off, but in the result data_end contains the offset in bytes.

Replace the alignment to sector size by division by sector size
and fix the comparision with s->header_size.

Signed-off-by: Alexander Ivanov <alexander.ivanov@virtuozzo.com>
---
 block/parallels.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/block/parallels.c b/block/parallels.c
index e6e8b9e369..7b4e997ebd 100644
--- a/block/parallels.c
+++ b/block/parallels.c
@@ -863,9 +863,9 @@ static int parallels_open(BlockDriverState *bs, QDict 
*options, int flags,
     }
     s->data_end = le32_to_cpu(ph.data_off);
     if (s->data_end == 0) {
-        s->data_end = ROUND_UP(bat_entry_off(s->bat_size), BDRV_SECTOR_SIZE);
+        s->data_end = DIV_ROUND_UP(size, BDRV_SECTOR_SIZE);
     }
-    if (s->data_end < s->header_size) {
+    if (s->data_end < (s->header_size >> BDRV_SECTOR_BITS)) {
         /* there is not enough unused space to fit to block align between BAT
            and actual data. We can't avoid read-modify-write... */
         s->header_size = size;
-- 
2.34.1