[Qemu-devel] [PATCH 0/2] block/vdi: Fix bmap writing error

[Max Reitz <mreitz@redhat.com>]

The bmap size in block/vdi.c may exceed INT_MAX. Using
bdrv_pwrite_sync() (which takes an int byte count) is therefore not a
good idea. The second patch of this series fixes this by replacing
bdrv_pwrite_sync() by bdrv_write()+bdrv_flush() (we don't need the p in
pwrite here).

The first patch employs ROUND_UP() and DIV_ROUND_UP() in block/vdi.c, so
you are reminded that bmap_size is aligned to BDRV_SECTOR_SIZE for the
second patch.

See https://bugzilla.redhat.com/show_bug.cgi?id=1154940 for a bug
report.

I will not include an iotest in this series because this would require
qemu to allocate and then write about 2G of data; yes, test 1 in 084
fails for me because qemu cannot allocate 4G for the bmap.

In fact, I can only test this once I'm home where I have more RAM
available (I made the mistake of activating swap space to test this only
once).


Max Reitz (2):
  block/vdi: Use {DIV_,}ROUND_UP
  block/vdi: Do not use bdrv_pwrite_sync() for bmap

 block/vdi.c | 18 ++++++++++++------
 1 file changed, 12 insertions(+), 6 deletions(-)

-- 
1.9.3