On Tue, Apr 14, 2015 at 11:57:35AM +0200, Kevin Wolf wrote: > Am 11.04.2015 um 05:41 hat Andreas Färber geschrieben: > > Hi, > > > > 001 seems to hang for -qcow (or is not reasonably "quick": >5 min). > > > > 033 is failing for -vhdx. > > > > (Note that `make check-block` only tests -qcow2, so didn't uncover > > either of them.) > > > > Given a failing test, am I seeing correctly that there is no command > > line option to skip this one failing test? -x seems to be for groups only. > > > > Regards, > > Andreas > > > > $ ./check -v -T -qcow -g quick > > [...] > > 001 6s ... [05:12:39] > > qcow1 is just really slow. 001 passes for me, after 202 seconds (that's > on my SSD, YMMV). > > > $ ./check -v -T -vhdx -g quick > > [...] > > 033 1s ... [04:06:09] [04:06:11] - output mismatch (see 033.out.bad) > > This seems to be because blkdebug doesn't implement .bdrv_truncate. > Currently the test case isn't suitable for VHDX, which uses explicit > bdrv_truncate() calls to grow the image file. I'll send a patch for > blkdebug to allow this. > > However, it seems that there is another problem which causes assertion > failures when using VHDX over blkdebug. Jeff, does the following fix > make sense to you? (I think it does, but I don't understand yet why the > assertion failure is only triggered with blkdebug - or in other words: > "how could this ever work?") > > Kevin
Kevin, Yes, looking at that fix it makes sense - we are wanting to pad the back part of the block after the actual data with zeros. That back length should be (block size - (bytes avail + block offset)), which is iov2.iov_len. There are two reasons I think we haven't seen this issue (it has been hidden): 1.) If bs->file supports zero init, we don't do any of this 2.) This is done for the case when the existing BAT state is PAYLOAD_BLOCK_ZERO. Until recently (commit 30af51c), we didn't create VHDX files with blocks in the PAYLOAD_BLOCK_ZERO state. So it has been a latent bug in a hitherto rarely (if ever) exercised path. Jeff > > --- a/block/vhdx.c > +++ b/block/vhdx.c > @@ -1285,7 +1285,7 @@ static coroutine_fn int vhdx_co_writev(BlockDriverState > *bs, int64_t sector_num, > iov2.iov_base = qemu_blockalign(bs, iov2.iov_len); > memset(iov2.iov_base, 0, iov2.iov_len); > qemu_iovec_concat_iov(&hd_qiov, &iov2, 1, 0, > - sinfo.block_offset); > + iov2.iov_len); > sectors_to_write += iov2.iov_len >> BDRV_SECTOR_BITS; > } > }
