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[Qemu-devel] [PATCH v4 01/11] nbd: Use BDRV_REQ_FUA for better FUA where
From: |
Eric Blake |
Subject: |
[Qemu-devel] [PATCH v4 01/11] nbd: Use BDRV_REQ_FUA for better FUA where supported |
Date: |
Wed, 11 May 2016 16:39:34 -0600 |
Rather than always flushing ourselves, let the block layer
forward the FUA on to the underlying device - where all
underlying layers also understand FUA, we are now more
efficient; and where any underlying layer doesn't understand
it, now the block layer takes care of the full flush fallback
on our behalf.
Signed-off-by: Eric Blake <address@hidden>
---
nbd/server.c | 16 ++++++----------
1 file changed, 6 insertions(+), 10 deletions(-)
diff --git a/nbd/server.c b/nbd/server.c
index fa862cd..6079249 100644
--- a/nbd/server.c
+++ b/nbd/server.c
@@ -1038,6 +1038,7 @@ static void nbd_trip(void *opaque)
struct nbd_reply reply;
ssize_t ret;
uint32_t command;
+ int flags;
TRACE("Reading request.");
if (client->closing) {
@@ -1114,23 +1115,18 @@ static void nbd_trip(void *opaque)
TRACE("Writing to device");
+ flags = 0;
+ if (request.type & NBD_CMD_FLAG_FUA) {
+ flags |= BDRV_REQ_FUA;
+ }
ret = blk_pwrite(exp->blk, request.from + exp->dev_offset,
- req->data, request.len, 0);
+ req->data, request.len, flags);
if (ret < 0) {
LOG("writing to file failed");
reply.error = -ret;
goto error_reply;
}
- if (request.type & NBD_CMD_FLAG_FUA) {
- ret = blk_co_flush(exp->blk);
- if (ret < 0) {
- LOG("flush failed");
- reply.error = -ret;
- goto error_reply;
- }
- }
-
if (nbd_co_send_reply(req, &reply, 0) < 0) {
goto out;
}
--
2.5.5
- [Qemu-devel] [PATCH v4 00/11] nbd: tighter protocol compliance, Eric Blake, 2016/05/11
- [Qemu-devel] [PATCH v4 01/11] nbd: Use BDRV_REQ_FUA for better FUA where supported,
Eric Blake <=
- [Qemu-devel] [PATCH v4 10/11] nbd: Detect servers that send unexpected error values, Eric Blake, 2016/05/11
- [Qemu-devel] [PATCH v4 11/11] nbd: Avoid magic number for NBD max name size, Eric Blake, 2016/05/11
- [Qemu-devel] [PATCH v4 07/11] nbd: Clean up ioctl handling of qemu-nbd -c, Eric Blake, 2016/05/11
- [Qemu-devel] [PATCH v4 06/11] nbd: Group all Linux-specific ioctl code in one place, Eric Blake, 2016/05/11
- [Qemu-devel] [PATCH v4 02/11] nbd: More debug typo fixes, use correct formats, Eric Blake, 2016/05/11
- [Qemu-devel] [PATCH v4 05/11] nbd: Reject unknown request flags, Eric Blake, 2016/05/11
- [Qemu-devel] [PATCH v4 08/11] nbd: Limit nbdflags to 16 bits, Eric Blake, 2016/05/11
- [Qemu-devel] [PATCH v4 09/11] nbd: Add qemu-nbd -D for human-readable description, Eric Blake, 2016/05/11