| Message ID | 1603390423-980205-8-git-send-email-andrey.shinkevich@virtuozzo.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Apply COR-filter to the block-stream permanently | expand |
22.10.2020 21:13, Andrey Shinkevich wrote: > Limit COR operations to the bottom node (inclusively) in the backing > chain when the bottom node name is given. It will be useful for a block > stream job when the COR-filter is applied. The bottom node is passed as > the base itself may change due to concurrent commit jobs on the same > backing chain. > > Signed-off-by: Andrey Shinkevich <andrey.shinkevich@virtuozzo.com> > --- > block/copy-on-read.c | 42 ++++++++++++++++++++++++++++++++++++++++-- > 1 file changed, 40 insertions(+), 2 deletions(-) > > diff --git a/block/copy-on-read.c b/block/copy-on-read.c > index 3d8e4db..8178a91 100644 > --- a/block/copy-on-read.c > +++ b/block/copy-on-read.c > @@ -123,8 +123,46 @@ static int coroutine_fn cor_co_preadv_part(BlockDriverState *bs, > size_t qiov_offset, > int flags) > { > - return bdrv_co_preadv_part(bs->file, offset, bytes, qiov, qiov_offset, > - flags | BDRV_REQ_COPY_ON_READ); > + int64_t n = 0; no need to initialize n actually. > + int local_flags; > + int ret; > + BDRVStateCOR *state = bs->opaque; > + > + if (!state->bottom_bs) { > + return bdrv_co_preadv_part(bs->file, offset, bytes, qiov, qiov_offset, > + flags | BDRV_REQ_COPY_ON_READ); > + } > + > + while (bytes) { > + local_flags = flags; > + > + /* In case of failure, try to copy-on-read anyway */ > + ret = bdrv_is_allocated(bs->file->bs, offset, bytes, &n); > + if (!ret || ret < 0) { simper: if (ret <= 0) { > + ret = bdrv_is_allocated_above(bdrv_backing_chain_next(bs->file->bs), > + state->bottom_bs, true, offset, > + n, &n); > + if (ret == 1 || ret < 0) { > + local_flags |= BDRV_REQ_COPY_ON_READ; > + } > + /* Finish earlier if the end of a backing file has been reached */ > + if (ret == 0 && n == 0) { "n == 0" should be enough > + break; > + } > + } > + > + ret = bdrv_co_preadv_part(bs->file, offset, n, qiov, qiov_offset, > + local_flags); > + if (ret < 0) { > + return ret; > + } > + > + offset += n; > + qiov_offset += n; > + bytes -= n; > + } > + > + return 0; > } > My remarks are minor, so: Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> And yes, I still think that this is good to be merged with two previous patches.
diff --git a/block/copy-on-read.c b/block/copy-on-read.c index 3d8e4db..8178a91 100644 --- a/block/copy-on-read.c +++ b/block/copy-on-read.c @@ -123,8 +123,46 @@ static int coroutine_fn cor_co_preadv_part(BlockDriverState *bs, size_t qiov_offset, int flags) { - return bdrv_co_preadv_part(bs->file, offset, bytes, qiov, qiov_offset, - flags | BDRV_REQ_COPY_ON_READ); + int64_t n = 0; + int local_flags; + int ret; + BDRVStateCOR *state = bs->opaque; + + if (!state->bottom_bs) { + return bdrv_co_preadv_part(bs->file, offset, bytes, qiov, qiov_offset, + flags | BDRV_REQ_COPY_ON_READ); + } + + while (bytes) { + local_flags = flags; + + /* In case of failure, try to copy-on-read anyway */ + ret = bdrv_is_allocated(bs->file->bs, offset, bytes, &n); + if (!ret || ret < 0) { + ret = bdrv_is_allocated_above(bdrv_backing_chain_next(bs->file->bs), + state->bottom_bs, true, offset, + n, &n); + if (ret == 1 || ret < 0) { + local_flags |= BDRV_REQ_COPY_ON_READ; + } + /* Finish earlier if the end of a backing file has been reached */ + if (ret == 0 && n == 0) { + break; + } + } + + ret = bdrv_co_preadv_part(bs->file, offset, n, qiov, qiov_offset, + local_flags); + if (ret < 0) { + return ret; + } + + offset += n; + qiov_offset += n; + bytes -= n; + } + + return 0; }
Limit COR operations to the bottom node (inclusively) in the backing chain when the bottom node name is given. It will be useful for a block stream job when the COR-filter is applied. The bottom node is passed as the base itself may change due to concurrent commit jobs on the same backing chain. Signed-off-by: Andrey Shinkevich <andrey.shinkevich@virtuozzo.com> --- block/copy-on-read.c | 42 ++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 40 insertions(+), 2 deletions(-)