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block/nbd: use non-blocking io channel for nbd negotiation

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No reason to use blocking channel for negotiation and we'll benefit in
further reconnect feature, as qio_channel reads and writes will do
qemu_coroutine_yield while waiting for io completion.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20190618114328.55249-3-vsementsov@virtuozzo.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
This commit is contained in:
Vladimir Sementsov-Ogievskiy 2019-06-18 14:43:21 +03:00 committed by Eric Blake
parent 962b7b3d4c
commit a8e2bb6a76
4 changed files with 21 additions and 16 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

16
block/nbd.c
View File

@ -1175,6 +1175,7 @@ static int nbd_client_connect(BlockDriverState *bs,
Error **errp)
{
BDRVNBDState *s = (BDRVNBDState *)bs->opaque;
AioContext *aio_context = bdrv_get_aio_context(bs);
int ret;
/*
@ -1189,15 +1190,16 @@ static int nbd_client_connect(BlockDriverState *bs,
/* NBD handshake */
trace_nbd_client_connect(export);
qio_channel_set_blocking(QIO_CHANNEL(sioc), true, NULL);
qio_channel_set_blocking(QIO_CHANNEL(sioc), false, NULL);
qio_channel_attach_aio_context(QIO_CHANNEL(sioc), aio_context);
s->info.request_sizes = true;
s->info.structured_reply = true;
s->info.base_allocation = true;
s->info.x_dirty_bitmap = g_strdup(x_dirty_bitmap);
s->info.name = g_strdup(export ?: "");
ret = nbd_receive_negotiate(QIO_CHANNEL(sioc), tlscreds, hostname,
&s->ioc, &s->info, errp);
ret = nbd_receive_negotiate(aio_context, QIO_CHANNEL(sioc), tlscreds,
hostname, &s->ioc, &s->info, errp);
g_free(s->info.x_dirty_bitmap);
g_free(s->info.name);
if (ret < 0) {
@ -1231,18 +1233,14 @@ static int nbd_client_connect(BlockDriverState *bs,
object_ref(OBJECT(s->ioc));
}
qio_channel_set_blocking(QIO_CHANNEL(sioc), false, NULL);
qio_channel_attach_aio_context(s->ioc, bdrv_get_aio_context(bs));
trace_nbd_client_connect_success(export);
return 0;
fail:
/*
* We have connected, but must fail for other reasons. The
* connection is still blocking; send NBD_CMD_DISC as a courtesy
* to the server.
* We have connected, but must fail for other reasons.
* Send NBD_CMD_DISC as a courtesy to the server.
*/
{
NBDRequest request = { .type = NBD_CMD_DISC };

3
include/block/nbd.h
View File

@ -304,7 +304,8 @@ struct NBDExportInfo {
};
typedef struct NBDExportInfo NBDExportInfo;
int nbd_receive_negotiate(QIOChannel *ioc, QCryptoTLSCreds *tlscreds,
int nbd_receive_negotiate(AioContext *aio_context, QIOChannel *ioc,
QCryptoTLSCreds *tlscreds,
const char *hostname, QIOChannel **outioc,
NBDExportInfo *info, Error **errp);
void nbd_free_export_list(NBDExportInfo *info, int count);

16
nbd/client.c
View File

@ -867,7 +867,8 @@ static int nbd_list_meta_contexts(QIOChannel *ioc,
* 2: server is newstyle, but lacks structured replies
* 3: server is newstyle and set up for structured replies
*/
static int nbd_start_negotiate(QIOChannel *ioc, QCryptoTLSCreds *tlscreds,
static int nbd_start_negotiate(AioContext *aio_context, QIOChannel *ioc,
QCryptoTLSCreds *tlscreds,
const char *hostname, QIOChannel **outioc,
bool structured_reply, bool *zeroes,
Error **errp)
@ -934,6 +935,10 @@ static int nbd_start_negotiate(QIOChannel *ioc, QCryptoTLSCreds *tlscreds,
return -EINVAL;
}
ioc = *outioc;
if (aio_context) {
qio_channel_set_blocking(ioc, false, NULL);
qio_channel_attach_aio_context(ioc, aio_context);
}
} else {
error_setg(errp, "Server does not support STARTTLS");
return -EINVAL;
@ -998,7 +1003,8 @@ static int nbd_negotiate_finish_oldstyle(QIOChannel *ioc, NBDExportInfo *info,
* Returns: negative errno: failure talking to server
* 0: server is connected
*/
int nbd_receive_negotiate(QIOChannel *ioc, QCryptoTLSCreds *tlscreds,
int nbd_receive_negotiate(AioContext *aio_context, QIOChannel *ioc,
QCryptoTLSCreds *tlscreds,
const char *hostname, QIOChannel **outioc,
NBDExportInfo *info, Error **errp)
{
@ -1009,7 +1015,7 @@ int nbd_receive_negotiate(QIOChannel *ioc, QCryptoTLSCreds *tlscreds,
assert(info->name);
trace_nbd_receive_negotiate_name(info->name);
result = nbd_start_negotiate(ioc, tlscreds, hostname, outioc,
result = nbd_start_negotiate(aio_context, ioc, tlscreds, hostname, outioc,
info->structured_reply, &zeroes, errp);
info->structured_reply = false;
@ -1129,8 +1135,8 @@ int nbd_receive_export_list(QIOChannel *ioc, QCryptoTLSCreds *tlscreds,
QIOChannel *sioc = NULL;
*info = NULL;
result = nbd_start_negotiate(ioc, tlscreds, hostname, &sioc, true, NULL,
errp);
result = nbd_start_negotiate(NULL, ioc, tlscreds, hostname, &sioc, true,
NULL, errp);
if (tlscreds && sioc) {
ioc = sioc;
}

2
qemu-nbd.c
View File

@ -362,7 +362,7 @@ static void *nbd_client_thread(void *arg)
goto out;
}
ret = nbd_receive_negotiate(QIO_CHANNEL(sioc),
ret = nbd_receive_negotiate(NULL, QIO_CHANNEL(sioc),
NULL, NULL, NULL, &info, &local_error);
if (ret < 0) {
if (local_error) {