diff options
author | Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> | 2018-07-09 19:37:16 +0300 |
---|---|---|
committer | Kevin Wolf <kwolf@redhat.com> | 2018-07-10 13:04:22 +0200 |
commit | 999658a05e61a8d87b65827da665302bb44ce8c9 (patch) | |
tree | 25e3fa25f83c869ae808cb081bc2570723893f2e /block/io.c | |
parent | e79c4cd1909c05a2cab6517a9c00445bd2d880a6 (diff) |
block/io: fix copy_range
Here two things are fixed:
1. Architecture
On each recursion step, we go to the child of src or dst, only for one
of them. So, it's wrong to create tracked requests for both on each
step. It leads to tracked requests duplication.
2. Wait for serializing requests on write path independently of
BDRV_REQ_NO_SERIALISING
Before commit 9ded4a01149 "backup: Use copy offloading",
BDRV_REQ_NO_SERIALISING was used for only one case: read in
copy-on-write operation during backup. Also, the flag was handled only
on read path (in bdrv_co_preadv and bdrv_aligned_preadv).
After 9ded4a01149, flag is used for not waiting serializing operations
on backup target (in same case of copy-on-write operation). This
behavior change is unsubstantiated and potentially dangerous, let's
drop it and add additional asserts and documentation.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Diffstat (limited to 'block/io.c')
-rw-r--r-- | block/io.c | 42 |
1 files changed, 27 insertions, 15 deletions
diff --git a/block/io.c b/block/io.c index 4c0831149c..3a321d69d3 100644 --- a/block/io.c +++ b/block/io.c @@ -1592,6 +1592,8 @@ static int coroutine_fn bdrv_aligned_pwritev(BdrvChild *child, max_transfer = QEMU_ALIGN_DOWN(MIN_NON_ZERO(bs->bl.max_transfer, INT_MAX), align); + /* BDRV_REQ_NO_SERIALISING is only for read operation */ + assert(!(flags & BDRV_REQ_NO_SERIALISING)); waited = wait_serialising_requests(req); assert(!waited || !req->serialising); assert(req->overlap_offset <= offset); @@ -2916,7 +2918,7 @@ static int coroutine_fn bdrv_co_copy_range_internal(BdrvChild *src, BdrvRequestFlags flags, bool recurse_src) { - BdrvTrackedRequest src_req, dst_req; + BdrvTrackedRequest req; int ret; if (!dst || !dst->bs) { @@ -2943,32 +2945,42 @@ static int coroutine_fn bdrv_co_copy_range_internal(BdrvChild *src, || src->bs->encrypted || dst->bs->encrypted) { return -ENOTSUP; } - bdrv_inc_in_flight(src->bs); - bdrv_inc_in_flight(dst->bs); - tracked_request_begin(&src_req, src->bs, src_offset, - bytes, BDRV_TRACKED_READ); - tracked_request_begin(&dst_req, dst->bs, dst_offset, - bytes, BDRV_TRACKED_WRITE); - if (!(flags & BDRV_REQ_NO_SERIALISING)) { - wait_serialising_requests(&src_req); - wait_serialising_requests(&dst_req); - } if (recurse_src) { + bdrv_inc_in_flight(src->bs); + tracked_request_begin(&req, src->bs, src_offset, bytes, + BDRV_TRACKED_READ); + + if (!(flags & BDRV_REQ_NO_SERIALISING)) { + wait_serialising_requests(&req); + } + ret = src->bs->drv->bdrv_co_copy_range_from(src->bs, src, src_offset, dst, dst_offset, bytes, flags); + + tracked_request_end(&req); + bdrv_dec_in_flight(src->bs); } else { + bdrv_inc_in_flight(dst->bs); + tracked_request_begin(&req, dst->bs, dst_offset, bytes, + BDRV_TRACKED_WRITE); + + /* BDRV_REQ_NO_SERIALISING is only for read operation, + * so we ignore it in flags. + */ + wait_serialising_requests(&req); + ret = dst->bs->drv->bdrv_co_copy_range_to(dst->bs, src, src_offset, dst, dst_offset, bytes, flags); + + tracked_request_end(&req); + bdrv_dec_in_flight(dst->bs); } - tracked_request_end(&src_req); - tracked_request_end(&dst_req); - bdrv_dec_in_flight(src->bs); - bdrv_dec_in_flight(dst->bs); + return ret; } |