From: Heinz Graalfs <graa...@linux.vnet.ibm.com>
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 <kw...@redhat.com>
CC: Stefan Hajnoczi <stefa...@redhat.com>
Signed-off-by: Heinz Graalfs <graa...@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntrae...@de.ibm.com>
---
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);
}
--
1.7.10.1
