block: Allow BDRV_REQ_FUA through blk_pwrite()

We have several block drivers that understand BDRV_REQ_FUA,
and emulate it in the block layer for the rest by a full flush.
But without a way to actually request BDRV_REQ_FUA during a
pass-through blk_pwrite(), FUA-aware block drivers like NBD are
forced to repeat the emulation logic of a full flush regardless
of whether the backend they are writing to could do it more
efficiently.

This patch just wires up a flags argument; followup patches
will actually make use of it in the NBD driver and in qemu-io.

Signed-off-by: Eric Blake <eblake@redhat.com>
Acked-by: Denis V. Lunev <den@openvz.org>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This commit is contained in:
Eric Blake 2016-05-06 10:26:27 -06:00 committed by Kevin Wolf
parent 0e01b76e7c
commit 8341f00dc2
15 changed files with 37 additions and 33 deletions

View file

@ -124,7 +124,7 @@ static void rtas_nvram_store(PowerPCCPU *cpu, sPAPRMachineState *spapr,
alen = len;
if (nvram->blk) {
alen = blk_pwrite(nvram->blk, offset, membuf, len);
alen = blk_pwrite(nvram->blk, offset, membuf, len, 0);
}
assert(nvram->buf);
@ -190,7 +190,7 @@ static int spapr_nvram_post_load(void *opaque, int version_id)
sPAPRNVRAM *nvram = VIO_SPAPR_NVRAM(opaque);
if (nvram->blk) {
int alen = blk_pwrite(nvram->blk, 0, nvram->buf, nvram->size);
int alen = blk_pwrite(nvram->blk, 0, nvram->buf, nvram->size, 0);
if (alen < 0) {
return alen;