diff options
| author | Paolo Bonzini <pbonzini@redhat.com> | 2013-09-04 19:00:27 +0200 |
|---|---|---|
| committer | Stefan Hajnoczi <stefanha@redhat.com> | 2013-09-06 15:25:09 +0200 |
| commit | 11212d8fa08a4e5bd56bb4f6877f9a4c0439a02b (patch) | |
| tree | 3b8b6048ac67fe76fdc1b279a66e403c3f91098b | |
| parent | e4a86f88cc6b214c37b4abe9160e41f0338ce4cd (diff) | |
| download | focaccia-qemu-11212d8fa08a4e5bd56bb4f6877f9a4c0439a02b.tar.gz focaccia-qemu-11212d8fa08a4e5bd56bb4f6877f9a4c0439a02b.zip | |
block: make bdrv_has_zero_init return false for copy-on-write-images
This helps implementing is_allocated on top of get_block_status. Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
| -rw-r--r-- | block.c | 5 | ||||
| -rw-r--r-- | qemu-img.c | 9 |
2 files changed, 6 insertions, 8 deletions
diff --git a/block.c b/block.c index 5df17de5a4..2a90893464 100644 --- a/block.c +++ b/block.c @@ -3031,6 +3031,11 @@ int bdrv_has_zero_init(BlockDriverState *bs) { assert(bs->drv); + /* If BS is a copy on write image, it is initialized to + the contents of the base image, which may not be zeroes. */ + if (bs->backing_hd) { + return 0; + } if (bs->drv->bdrv_has_zero_init) { return bs->drv->bdrv_has_zero_init(bs); } diff --git a/qemu-img.c b/qemu-img.c index 5cc579df1f..b074fa7912 100644 --- a/qemu-img.c +++ b/qemu-img.c @@ -1537,14 +1537,7 @@ static int img_convert(int argc, char **argv) should add a specific call to have the info to go faster */ buf1 = buf; while (n > 0) { - /* If the output image is being created as a copy on write image, - copy all sectors even the ones containing only NUL bytes, - because they may differ from the sectors in the base image. - - If the output is to a host device, we also write out - sectors that are entirely 0, since whatever data was - already there is garbage, not 0s. */ - if (!has_zero_init || out_baseimg || + if (!has_zero_init || is_allocated_sectors_min(buf1, n, &n1, min_sparse)) { ret = bdrv_write(out_bs, sector_num, buf1, n1); if (ret < 0) { |