diff options
| author | Fam Zheng <famz@redhat.com> | 2015-06-08 13:56:09 +0800 |
|---|---|---|
| committer | Michael Roth <mdroth@linux.vnet.ibm.com> | 2015-07-29 21:46:07 -0500 |
| commit | 27ed14c4d7decd359edb7fec0c8a39971ef32a72 (patch) | |
| tree | a9d5af339c7ddb3f048dbc6de54d757b72412025 | |
| parent | 6a45a1b8e45bf3396dd4901a5f7cbadc3780f250 (diff) | |
| download | qemu-27ed14c4d7decd359edb7fec0c8a39971ef32a72.tar.gz | |
mirror: Do zero write on target if sectors not allocated
If guest discards a source cluster, mirroring with bdrv_aio_readv is overkill.
Some protocols do zero upon discard, where it's best to use
bdrv_aio_write_zeroes, otherwise, bdrv_aio_discard will be enough.
Signed-off-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
(cherry picked from commit dcfb3beb5130694b76b57de109619fcbf9c7e5b5)
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
| -rw-r--r-- | block/mirror.c | 20 |
1 files changed, 18 insertions, 2 deletions
diff --git a/block/mirror.c b/block/mirror.c index 1814523e6c..bd079a4398 100644 --- a/block/mirror.c +++ b/block/mirror.c @@ -168,6 +168,8 @@ static uint64_t coroutine_fn mirror_iteration(MirrorBlockJob *s) int64_t end, sector_num, next_chunk, next_sector, hbitmap_next_sector; uint64_t delay_ns = 0; MirrorOp *op; + int pnum; + int64_t ret; s->sector_num = hbitmap_iter_next(&s->hbi); if (s->sector_num < 0) { @@ -296,8 +298,22 @@ static uint64_t coroutine_fn mirror_iteration(MirrorBlockJob *s) s->in_flight++; s->sectors_in_flight += nb_sectors; trace_mirror_one_iteration(s, sector_num, nb_sectors); - bdrv_aio_readv(source, sector_num, &op->qiov, nb_sectors, - mirror_read_complete, op); + + ret = bdrv_get_block_status_above(source, NULL, sector_num, + nb_sectors, &pnum); + if (ret < 0 || pnum < nb_sectors || + (ret & BDRV_BLOCK_DATA && !(ret & BDRV_BLOCK_ZERO))) { + bdrv_aio_readv(source, sector_num, &op->qiov, nb_sectors, + mirror_read_complete, op); + } else if (ret & BDRV_BLOCK_ZERO) { + bdrv_aio_write_zeroes(s->target, sector_num, op->nb_sectors, + s->unmap ? BDRV_REQ_MAY_UNMAP : 0, + mirror_write_complete, op); + } else { + assert(!(ret & BDRV_BLOCK_DATA)); + bdrv_aio_discard(s->target, sector_num, op->nb_sectors, + mirror_write_complete, op); + } return delay_ns; } |