Am 09.06.2015 um 11:47 hat Wen Congyang geschrieben: > On 06/09/2015 04:55 PM, Kevin Wolf wrote: > > Image files with an unaligned image size have a final hole that starts > > at EOF, i.e. in the middle of a sector. Currently, *pnum == 0 is > > returned when checking the status of this sector. In qemu-img, this > > triggers an assertion failure. > > > > In order to fix this, one type for the sector that contains EOF must be > > found. Treating a hole as data is safe, so this patch rounds the > > calculated number of data sectors up, so that a partial sector at EOF is > > treated as a full data sector. > > > > This fixes https://bugzilla.redhat.com/show_bug.cgi?id=1229394 > > > > Signed-off-by: Kevin Wolf <kw...@redhat.com> > > --- > > block/raw-posix.c | 5 +++-- > > 1 file changed, 3 insertions(+), 2 deletions(-) > > > > diff --git a/block/raw-posix.c b/block/raw-posix.c > > index 2990e95..44ade8c 100644 > > --- a/block/raw-posix.c > > +++ b/block/raw-posix.c > > @@ -1848,8 +1848,9 @@ static int64_t coroutine_fn > > raw_co_get_block_status(BlockDriverState *bs, > > *pnum = nb_sectors; > > ret = BDRV_BLOCK_DATA; > > } else if (data == start) { > > - /* On a data extent, compute sectors to the end of the extent. */ > > - *pnum = MIN(nb_sectors, (hole - start) / BDRV_SECTOR_SIZE); > > + /* On a data extent, compute sectors to the end of the extent, > > + * possibly including a partial sector at EOF. */ > > Not only for EOF. If the hole and start are in the same sector, (hole - > start) / BDRV_SECTOR_SIZE > will be 0 > > > + *pnum = MIN(nb_sectors, DIV_ROUND_UP(hole - start, > > BDRV_SECTOR_SIZE)); > > ret = BDRV_BLOCK_DATA; > > } else { > > /* On a hole, compute sectors to the beginning of the next extent. > > */ > > > > So, if start is hole, data and start are in the same sector, (data - start) > / BDRV_SECTOR_SIZE > will be 0, you also need to fix it here.
At first, I thought the same. But how would you ever get a hole that starts in the middle of a sector? You would have to have a filesystem with a block size smaller than 512. I don't think that it exists. Kevin
