Commit 0d51b4de authored by Asias He's avatar Asias He Committed by Stefan Hajnoczi
Browse files

block: Introduce bs->zero_beyond_eof 



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.

[Since the broken patch "block: Produce zeros when protocols reading
beyond end of file" has not been merged yet, I have applied this fix
*first* and will then apply the next patch to keep the tree bisectable.
-- Stefan]

Suggested-by: default avatarStefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: default avatarAsias He <asias@redhat.com>
Signed-off-by: default avatarStefan Hajnoczi <stefanha@redhat.com>
parent 8ad1898c

block.c

+2 −0
Original line number Diff line number Diff line
@@ -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;

block/qcow2.c

+3 −0
Original line number Diff line number Diff line
@@ -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;

}

include/block/block_int.h

+3 −0
Original line number Diff line number Diff line
@@ -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;