| Message ID | 1377156254-14377-1-git-send-email-asias@redhat.com |
|---|---|
| State | New |
| Headers | show |
On Thu, Aug 22, 2013 at 03:24:14PM +0800, Asias He wrote: > In 4146b46c42e0989cb5842e04d88ab6ccb1713a48 (block: Produce zeros when > protocols reading beyond end of file), we break qemu-iotests ./check > -qcow2 022. This happens because qcow2 temporarily sets ->growable = 1 > for vmstate accesses (which are stored beyond the end of regular image > data). > > We introduce the bs->zero_beyond_eof to allow qcow2_load_vmstate() to > disable ->zero_beyond_eof temporarily in addition to enable ->growable. > > Suggested-by: Stefan Hajnoczi <stefanha@redhat.com> > Signed-off-by: Asias He <asias@redhat.com> > --- > Changes in v2: Set bs->zero_beyond_eof in bdrv_open_common > > block.c | 4 +++- > block/qcow2.c | 3 +++ > include/block/block_int.h | 3 +++ > 3 files changed, 9 insertions(+), 1 deletion(-) Thanks, applied to my block tree: https://github.com/stefanha/qemu/commits/block ...with a little twist: since the broken patch hasn't been merged yet I'm applying this fix *first* to keep the tree bisectable. Stefan
On Thu, Aug 22, 2013 at 02:12:29PM +0200, Stefan Hajnoczi wrote: > On Thu, Aug 22, 2013 at 03:24:14PM +0800, Asias He wrote: > > In 4146b46c42e0989cb5842e04d88ab6ccb1713a48 (block: Produce zeros when > > protocols reading beyond end of file), we break qemu-iotests ./check > > -qcow2 022. This happens because qcow2 temporarily sets ->growable = 1 > > for vmstate accesses (which are stored beyond the end of regular image > > data). > > > > We introduce the bs->zero_beyond_eof to allow qcow2_load_vmstate() to > > disable ->zero_beyond_eof temporarily in addition to enable ->growable. > > > > Suggested-by: Stefan Hajnoczi <stefanha@redhat.com> > > Signed-off-by: Asias He <asias@redhat.com> > > --- > > Changes in v2: Set bs->zero_beyond_eof in bdrv_open_common > > > > block.c | 4 +++- > > block/qcow2.c | 3 +++ > > include/block/block_int.h | 3 +++ > > 3 files changed, 9 insertions(+), 1 deletion(-) > > Thanks, applied to my block tree: > https://github.com/stefanha/qemu/commits/block > > ...with a little twist: since the broken patch hasn't been merged yet > I'm applying this fix *first* to keep the tree bisectable. Thanks! > Stefan
diff --git a/block.c b/block.c index f3cd9fb..6668c05 100644 --- a/block.c +++ b/block.c @@ -706,6 +706,7 @@ static int bdrv_open_common(BlockDriverState *bs, BlockDriverState *file, bs->open_flags = flags; bs->buffer_alignment = 512; + bs->zero_beyond_eof = true; open_flags = bdrv_open_flags(bs, flags); bs->read_only = !(open_flags & BDRV_O_RDWR); @@ -1402,6 +1403,7 @@ void bdrv_close(BlockDriverState *bs) bs->valid_key = 0; bs->sg = 0; bs->growable = 0; + bs->zero_beyond_eof = false; QDECREF(bs->options); bs->options = NULL; @@ -2544,7 +2546,7 @@ static int coroutine_fn bdrv_co_do_readv(BlockDriverState *bs, } } - if (!bs->growable) { + if (!(bs->zero_beyond_eof && bs->growable)) { ret = drv->bdrv_co_readv(bs, sector_num, nb_sectors, qiov); } else { /* Read zeros after EOF of growable BDSes */ diff --git a/block/qcow2.c b/block/qcow2.c index 3376901..14e863d 100644 --- a/block/qcow2.c +++ b/block/qcow2.c @@ -1722,12 +1722,15 @@ static int qcow2_load_vmstate(BlockDriverState *bs, uint8_t *buf, { BDRVQcowState *s = bs->opaque; int growable = bs->growable; + bool zero_beyond_eof = bs->zero_beyond_eof; int ret; BLKDBG_EVENT(bs->file, BLKDBG_VMSTATE_LOAD); bs->growable = 1; + bs->zero_beyond_eof = false; ret = bdrv_pread(bs, qcow2_vm_state_offset(s) + pos, buf, size); bs->growable = growable; + bs->zero_beyond_eof = zero_beyond_eof; return ret; } diff --git a/include/block/block_int.h b/include/block/block_int.h index e45f2a0..74b0689 100644 --- a/include/block/block_int.h +++ b/include/block/block_int.h @@ -281,6 +281,9 @@ struct BlockDriverState { /* Whether the disk can expand beyond total_sectors */ int growable; + /* Whether produces zeros when read beyond eof */ + bool zero_beyond_eof; + /* the memory alignment required for the buffers handled by this driver */ int buffer_alignment;
In 4146b46c42e0989cb5842e04d88ab6ccb1713a48 (block: Produce zeros when protocols reading beyond end of file), we break qemu-iotests ./check -qcow2 022. This happens because qcow2 temporarily sets ->growable = 1 for vmstate accesses (which are stored beyond the end of regular image data). We introduce the bs->zero_beyond_eof to allow qcow2_load_vmstate() to disable ->zero_beyond_eof temporarily in addition to enable ->growable. Suggested-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Asias He <asias@redhat.com> --- Changes in v2: Set bs->zero_beyond_eof in bdrv_open_common block.c | 4 +++- block/qcow2.c | 3 +++ include/block/block_int.h | 3 +++ 3 files changed, 9 insertions(+), 1 deletion(-)