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

@ -788,13 +788,13 @@ static int create_dynamic_disk(BlockBackend *blk, uint8_t *buf,
block_size = 0x200000;
num_bat_entries = (total_sectors + block_size / 512) / (block_size / 512);
ret = blk_pwrite(blk, offset, buf, HEADER_SIZE);
ret = blk_pwrite(blk, offset, buf, HEADER_SIZE, 0);
if (ret < 0) {
goto fail;
}
offset = 1536 + ((num_bat_entries * 4 + 511) & ~511);
ret = blk_pwrite(blk, offset, buf, HEADER_SIZE);
ret = blk_pwrite(blk, offset, buf, HEADER_SIZE, 0);
if (ret < 0) {
goto fail;
}
@ -804,7 +804,7 @@ static int create_dynamic_disk(BlockBackend *blk, uint8_t *buf,
memset(buf, 0xFF, 512);
for (i = 0; i < (num_bat_entries * 4 + 511) / 512; i++) {
ret = blk_pwrite(blk, offset, buf, 512);
ret = blk_pwrite(blk, offset, buf, 512, 0);
if (ret < 0) {
goto fail;
}
@ -831,7 +831,7 @@ static int create_dynamic_disk(BlockBackend *blk, uint8_t *buf,
/* Write the header */
offset = 512;
ret = blk_pwrite(blk, offset, buf, 1024);
ret = blk_pwrite(blk, offset, buf, 1024, 0);
if (ret < 0) {
goto fail;
}
@ -853,7 +853,7 @@ static int create_fixed_disk(BlockBackend *blk, uint8_t *buf,
return ret;
}
ret = blk_pwrite(blk, total_size - HEADER_SIZE, buf, HEADER_SIZE);
ret = blk_pwrite(blk, total_size - HEADER_SIZE, buf, HEADER_SIZE, 0);
if (ret < 0) {
return ret;
}