On 06/09/2015 05:49 PM, Kevin Wolf wrote: > 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.
You are right, I don't find such filesystem. Thanks Wen Congyang > > Kevin > . >
