diff mbox series

[PULL,03/18] parallels: Incorrect data end calculation in parallels_open()

Message ID 20230906154942.656537-4-den@openvz.org (mailing list archive)
State New, archived
Headers show
Series Parallels format driver | expand

Commit Message

Denis V. Lunev Sept. 6, 2023, 3:49 p.m. UTC 
From: Alexander Ivanov <alexander.ivanov@virtuozzo.com>

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>
Reviewed-by: Denis V. Lunev <den@openvz.org>
Reviewed-by: Hanna Czenczek <hreitz@redhat.com>
Signed-off-by: Denis V. Lunev <den@openvz.org>
---
 block/parallels.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
diff mbox series

Patch

diff --git a/block/parallels.c b/block/parallels.c
index c7b2ed5a54..3c0dca3dbf 100644
--- a/block/parallels.c
+++ b/block/parallels.c
@@ -865,9 +865,9 @@  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...