From patchwork Wed Nov 21 08:58:07 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Subject: [PATCH/RFC] block: Ensure that block size constraints are considered From: Christian Borntraeger X-Patchwork-Id: 200609 Message-Id: <1353488287-47077-1-git-send-email-borntraeger@de.ibm.com> To: qemu-devel@nongnu.org Cc: Kevin Wolf , Heinz Graalfs , agraf@suse.de, Christian Borntraeger , jfrei@linux.vnet.ibm.com, Stefan Hajnoczi Date: Wed, 21 Nov 2012 09:58:07 +0100 From: Heinz Graalfs While testing IPL code (booting) for s390x we faced some problems with cache=none on dasds (4k block size) on bdrv_preads with length values != block size. This patch makes sure that bdrv_pread and friends work fine with unaligned access even with cache=none - propagate alignment value also into bs->file struct - modify the size in case of no cache to avoid EINVAL on pread() etc. (file was opened with O_DIRECT). This patch seems to cure the problems. CC: Kevin Wolf CC: Stefan Hajnoczi Signed-off-by: Heinz Graalfs Signed-off-by: Christian Borntraeger --- block.c | 3 +++ block/raw-posix.c | 6 ++++++ 2 files changed, 9 insertions(+) diff --git a/block.c b/block.c index 854ebd6..f23c562 100644 --- a/block.c +++ b/block.c @@ -4242,6 +4242,9 @@ BlockDriverAIOCB *bdrv_aio_ioctl(BlockDriverState *bs, void bdrv_set_buffer_alignment(BlockDriverState *bs, int align) { bs->buffer_alignment = align; + if ((bs->open_flags & BDRV_O_NOCACHE)) { + bs->file->buffer_alignment = align; + } } void *qemu_blockalign(BlockDriverState *bs, size_t size) diff --git a/block/raw-posix.c b/block/raw-posix.c index f2f0404..baebf1d 100644 --- a/block/raw-posix.c +++ b/block/raw-posix.c @@ -700,6 +700,12 @@ static BlockDriverAIOCB *paio_submit(BlockDriverState *bs, int fd, acb->aio_nbytes = nb_sectors * 512; acb->aio_offset = sector_num * 512; + /* O_DIRECT also requires an aligned length */ + if (bs->open_flags & BDRV_O_NOCACHE) { + acb->aio_nbytes += acb->bs->buffer_alignment - 1; + acb->aio_nbytes &= ~(acb->bs->buffer_alignment - 1); + } + trace_paio_submit(acb, opaque, sector_num, nb_sectors, type); return thread_pool_submit_aio(aio_worker, acb, cb, opaque); }