From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([140.186.70.92]:46303) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1R1gbJ-0003Uc-DQ for qemu-devel@nongnu.org; Thu, 08 Sep 2011 11:33:15 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1R1gbI-0002Sl-5V for qemu-devel@nongnu.org; Thu, 08 Sep 2011 11:33:13 -0400 Received: from mail-ew0-f45.google.com ([209.85.215.45]:45670) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1R1gbI-0002Sd-0x for qemu-devel@nongnu.org; Thu, 08 Sep 2011 11:33:12 -0400 Received: by ewy24 with SMTP id 24so468255ewy.4 for ; Thu, 08 Sep 2011 08:33:11 -0700 (PDT) Sender: Paolo Bonzini From: Paolo Bonzini Date: Thu, 8 Sep 2011 17:24:58 +0200 Message-Id: <1315495505-28906-6-git-send-email-pbonzini@redhat.com> In-Reply-To: <1315495505-28906-1-git-send-email-pbonzini@redhat.com> References: <1315495505-28906-1-git-send-email-pbonzini@redhat.com> Subject: [Qemu-devel] [PATCH 05/12] nbd: add support for NBD_CMD_FLAG_FUA List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org The server can use it to issue a flush automatically after a write. The client can also use it to mimic a write-through cache. Signed-off-by: Paolo Bonzini --- block/nbd.c | 8 ++++++++ nbd.c | 13 +++++++++++-- 2 files changed, 19 insertions(+), 2 deletions(-) diff --git a/block/nbd.c b/block/nbd.c index 4a195dc..5a7812c 100644 --- a/block/nbd.c +++ b/block/nbd.c @@ -215,6 +215,10 @@ static int nbd_write(BlockDriverState *bs, int64_t sector_num, struct nbd_reply reply; request.type = NBD_CMD_WRITE; + if (!bdrv_enable_write_cache(bs) && (s->nbdflags & NBD_FLAG_SEND_FUA)) { + request.type |= NBD_CMD_FLAG_FUA; + } + request.handle = (uint64_t)(intptr_t)bs; request.from = sector_num * 512;; request.len = nb_sectors * 512; @@ -248,6 +252,10 @@ static int nbd_flush(BlockDriverState *bs) } request.type = NBD_CMD_FLUSH; + if (s->nbdflags & NBD_FLAG_SEND_FUA) { + request.type |= NBD_CMD_FLAG_FUA; + } + request.handle = (uint64_t)(intptr_t)bs; request.from = 0; request.len = 0; diff --git a/nbd.c b/nbd.c index 4dbbc62..b65fb4a 100644 --- a/nbd.c +++ b/nbd.c @@ -194,7 +194,8 @@ int nbd_negotiate(int csock, off_t size, uint32_t flags) cpu_to_be64w((uint64_t*)(buf + 8), 0x00420281861253LL); cpu_to_be64w((uint64_t*)(buf + 16), size); cpu_to_be32w((uint32_t*)(buf + 24), - flags | NBD_FLAG_HAS_FLAGS | NBD_FLAG_SEND_FLUSH); + flags | NBD_FLAG_HAS_FLAGS | + NBD_FLAG_SEND_FLUSH | NBD_FLAG_SEND_FUA); memset(buf + 28, 0, 124); if (write_sync(csock, buf, sizeof(buf)) != sizeof(buf)) { @@ -614,7 +615,7 @@ int nbd_trip(BlockDriverState *bs, int csock, off_t size, uint64_t dev_offset, reply.handle = request.handle; reply.error = 0; - switch (request.type) { + switch (request.type & NBD_CMD_MASK_COMMAND) { case NBD_CMD_READ: TRACE("Request type is READ"); @@ -674,6 +675,14 @@ int nbd_trip(BlockDriverState *bs, int csock, off_t size, uint64_t dev_offset, } *offset += request.len; + + if (request.type & NBD_CMD_FLAG_FUA) { + if (bdrv_flush(bs) == -1) { + LOG("flush failed"); + errno = EINVAL; + return -1; + } + } } if (nbd_send_reply(csock, &reply) == -1) -- 1.7.6