Message ID | 20180531205046.153256-3-eblake@redhat.com |
---|---|
State | New |
Headers | show |
Series | block: more byte-based cleanups: vectored I/O | expand |
On Thu, May 31, 2018 at 03:50:40PM -0500, Eric Blake wrote: > We are gradually moving away from sector-based interfaces, towards > byte-based. Make the change for the internal helper function > get_cluster_offset(), by changing n_start and n_end to by byte s/by\ byte/be\ byte/ > offsets rather than sector indices within the cluster being > allocated. However, assert that these values are still > sector-aligned (at least qcrypto_block_encrypt() still wants that). > For now we get that alignment for free because we still use > sector-based driver callbacks. > > A later patch will then switch the qcow driver as a whole over > to byte-based operation; but will still leave things at sector > alignments as it is not worth auditing the qcow image format > to worry about sub-sector requests. > > Signed-off-by: Eric Blake <eblake@redhat.com> Reviewed-by: Jeff Cody <jcody@redhat.com> > > --- > v2: assert sector alignment [Max] > --- > block/qcow.c | 29 +++++++++++++++-------------- > 1 file changed, 15 insertions(+), 14 deletions(-) > > diff --git a/block/qcow.c b/block/qcow.c > index 3ba2ca25ea5..42d1bbb7643 100644 > --- a/block/qcow.c > +++ b/block/qcow.c > @@ -345,8 +345,8 @@ static int qcow_reopen_prepare(BDRVReopenState *state, > * > * 0 to not allocate. > * > - * 1 to allocate a normal cluster (for sector indexes 'n_start' to > - * 'n_end') > + * 1 to allocate a normal cluster (for sector-aligned byte offsets 'n_start' > + * to 'n_end' within the cluster) > * > * 2 to allocate a compressed cluster of size > * 'compressed_size'. 'compressed_size' must be > 0 and < > @@ -440,9 +440,10 @@ static int get_cluster_offset(BlockDriverState *bs, > if (!allocate) > return 0; > BLKDBG_EVENT(bs->file, BLKDBG_CLUSTER_ALLOC); > + assert(QEMU_IS_ALIGNED(n_start | n_end, BDRV_SECTOR_SIZE)); > /* allocate a new cluster */ > if ((cluster_offset & QCOW_OFLAG_COMPRESSED) && > - (n_end - n_start) < s->cluster_sectors) { > + (n_end - n_start) < s->cluster_size) { > /* if the cluster is already compressed, we must > decompress it in the case it is not completely > overwritten */ > @@ -480,16 +481,15 @@ static int get_cluster_offset(BlockDriverState *bs, > /* if encrypted, we must initialize the cluster > content which won't be written */ > if (bs->encrypted && > - (n_end - n_start) < s->cluster_sectors) { > - uint64_t start_sect; > + (n_end - n_start) < s->cluster_size) { > + uint64_t start_offset; > assert(s->crypto); > - start_sect = (offset & ~(s->cluster_size - 1)) >> 9; > - for(i = 0; i < s->cluster_sectors; i++) { > + start_offset = offset & ~(s->cluster_size - 1); > + for (i = 0; i < s->cluster_size; i += BDRV_SECTOR_SIZE) { > if (i < n_start || i >= n_end) { > - memset(s->cluster_data, 0x00, 512); > + memset(s->cluster_data, 0x00, BDRV_SECTOR_SIZE); > if (qcrypto_block_encrypt(s->crypto, > - (start_sect + i) * > - BDRV_SECTOR_SIZE, > + start_offset + i, > s->cluster_data, > BDRV_SECTOR_SIZE, > NULL) < 0) { > @@ -497,8 +497,9 @@ static int get_cluster_offset(BlockDriverState *bs, > } > BLKDBG_EVENT(bs->file, BLKDBG_WRITE_AIO); > ret = bdrv_pwrite(bs->file, > - cluster_offset + i * 512, > - s->cluster_data, 512); > + cluster_offset + i, > + s->cluster_data, > + BDRV_SECTOR_SIZE); > if (ret < 0) { > return ret; > } > @@ -758,8 +759,8 @@ static coroutine_fn int qcow_co_writev(BlockDriverState *bs, int64_t sector_num, > n = nb_sectors; > } > ret = get_cluster_offset(bs, sector_num << 9, 1, 0, > - index_in_cluster, > - index_in_cluster + n, &cluster_offset); > + index_in_cluster << 9, > + (index_in_cluster + n) << 9, &cluster_offset); > if (ret < 0) { > break; > } > -- > 2.14.3 > >
diff --git a/block/qcow.c b/block/qcow.c index 3ba2ca25ea5..42d1bbb7643 100644 --- a/block/qcow.c +++ b/block/qcow.c @@ -345,8 +345,8 @@ static int qcow_reopen_prepare(BDRVReopenState *state, * * 0 to not allocate. * - * 1 to allocate a normal cluster (for sector indexes 'n_start' to - * 'n_end') + * 1 to allocate a normal cluster (for sector-aligned byte offsets 'n_start' + * to 'n_end' within the cluster) * * 2 to allocate a compressed cluster of size * 'compressed_size'. 'compressed_size' must be > 0 and < @@ -440,9 +440,10 @@ static int get_cluster_offset(BlockDriverState *bs, if (!allocate) return 0; BLKDBG_EVENT(bs->file, BLKDBG_CLUSTER_ALLOC); + assert(QEMU_IS_ALIGNED(n_start | n_end, BDRV_SECTOR_SIZE)); /* allocate a new cluster */ if ((cluster_offset & QCOW_OFLAG_COMPRESSED) && - (n_end - n_start) < s->cluster_sectors) { + (n_end - n_start) < s->cluster_size) { /* if the cluster is already compressed, we must decompress it in the case it is not completely overwritten */ @@ -480,16 +481,15 @@ static int get_cluster_offset(BlockDriverState *bs, /* if encrypted, we must initialize the cluster content which won't be written */ if (bs->encrypted && - (n_end - n_start) < s->cluster_sectors) { - uint64_t start_sect; + (n_end - n_start) < s->cluster_size) { + uint64_t start_offset; assert(s->crypto); - start_sect = (offset & ~(s->cluster_size - 1)) >> 9; - for(i = 0; i < s->cluster_sectors; i++) { + start_offset = offset & ~(s->cluster_size - 1); + for (i = 0; i < s->cluster_size; i += BDRV_SECTOR_SIZE) { if (i < n_start || i >= n_end) { - memset(s->cluster_data, 0x00, 512); + memset(s->cluster_data, 0x00, BDRV_SECTOR_SIZE); if (qcrypto_block_encrypt(s->crypto, - (start_sect + i) * - BDRV_SECTOR_SIZE, + start_offset + i, s->cluster_data, BDRV_SECTOR_SIZE, NULL) < 0) { @@ -497,8 +497,9 @@ static int get_cluster_offset(BlockDriverState *bs, } BLKDBG_EVENT(bs->file, BLKDBG_WRITE_AIO); ret = bdrv_pwrite(bs->file, - cluster_offset + i * 512, - s->cluster_data, 512); + cluster_offset + i, + s->cluster_data, + BDRV_SECTOR_SIZE); if (ret < 0) { return ret; } @@ -758,8 +759,8 @@ static coroutine_fn int qcow_co_writev(BlockDriverState *bs, int64_t sector_num, n = nb_sectors; } ret = get_cluster_offset(bs, sector_num << 9, 1, 0, - index_in_cluster, - index_in_cluster + n, &cluster_offset); + index_in_cluster << 9, + (index_in_cluster + n) << 9, &cluster_offset); if (ret < 0) { break; }
We are gradually moving away from sector-based interfaces, towards byte-based. Make the change for the internal helper function get_cluster_offset(), by changing n_start and n_end to by byte offsets rather than sector indices within the cluster being allocated. However, assert that these values are still sector-aligned (at least qcrypto_block_encrypt() still wants that). For now we get that alignment for free because we still use sector-based driver callbacks. A later patch will then switch the qcow driver as a whole over to byte-based operation; but will still leave things at sector alignments as it is not worth auditing the qcow image format to worry about sub-sector requests. Signed-off-by: Eric Blake <eblake@redhat.com> --- v2: assert sector alignment [Max] --- block/qcow.c | 29 +++++++++++++++-------------- 1 file changed, 15 insertions(+), 14 deletions(-)