Skip to contentSkip to conversation

nbd client refactoring and fixing

PATCH In review Vladimir Sementsov-Ogievskiy 2 participants 8 messages Sep 20, 2017 – Sep 21, 2017 Block layer

lore
Share & tools
lore

Vladimir Sementsov-Ogievskiy

author
#0 lore raw

v3 cover nbd client refactoring and fixing

v3: dropped all controversial things. I'll try to implement minimal structured reply and block status over this small residue.

Vladimir Sementsov-Ogievskiy (3):
block/nbd-client: refactor nbd_co_receive_reply block/nbd-client: simplify check in nbd_co_receive_reply block/nbd-client: nbd_co_send_request: fix return code

 block/nbd-client.c | 33 ++++++++++++++++++---------------
 1 file changed, 18 insertions(+), 15 deletions(-)
Signature · 1 line
2.11.1
author
#1 lore raw

PATCH v3 1/3 block/nbd-client: refactor nbd_co_receive_reply

"NBDReply *reply" parameter of nbd_co_receive_reply is used only to pass return value for nbd_co_request (reply.error). Remove it and use function return value instead.

Signed-off-by Vladimir Sementsov-Ogievskiy <[email protected]>
Reviewed-by Eric Blake <[email protected]>
---
 block/nbd-client.c | 30 +++++++++++++++---------------
 1 file changed, 15 insertions(+), 15 deletions(-)
block/nbd-client.c +15 -15
index ee7f758e68..acd8e5d007 100644
@@ -178,26 +178,26 @@ err:
     return rc;
 }
 
-static void nbd_co_receive_reply(NBDClientSession *s,
-                                 NBDRequest *request,
-                                 NBDReply *reply,
-                                 QEMUIOVector *qiov)
+static int nbd_co_receive_reply(NBDClientSession *s,
+                                NBDRequest *request,
+                                QEMUIOVector *qiov)
 {
+    int ret;
     int i = HANDLE_TO_INDEX(s, request->handle);
 
     /* Wait until we're woken up by nbd_read_reply_entry.  */
     s->requests[i].receiving = true;
     qemu_coroutine_yield();
     s->requests[i].receiving = false;
-    *reply = s->reply;
-    if (reply->handle != request->handle || !s->ioc || s->quit) {
-        reply->error = EIO;
+    if (s->reply.handle != request->handle || !s->ioc || s->quit) {
+        ret = -EIO;
     } else {
-        if (qiov && reply->error == 0) {
+        ret = -s->reply.error;
+        if (qiov && s->reply.error == 0) {
             assert(request->len == iov_size(qiov->iov, qiov->niov));
             if (qio_channel_readv_all(s->ioc, qiov->iov, qiov->niov,
                                       NULL) < 0) {
-                reply->error = EIO;
+                ret = -EIO;
                 s->quit = true;
             }
         }

@@ -217,6 +217,8 @@ static void nbd_co_receive_reply(NBDClientSession *s,
     s->in_flight--;
     qemu_co_queue_next(&s->free_sema);
     qemu_co_mutex_unlock(&s->send_mutex);
+
+    return ret;
 }
 
 static int nbd_co_request(BlockDriverState *bs,

@@ -224,7 +226,6 @@ static int nbd_co_request(BlockDriverState *bs,
                           QEMUIOVector *qiov)
 {
     NBDClientSession *client = nbd_get_client_session(bs);
-    NBDReply reply;
     int ret;
 
     assert(!qiov || request->type == NBD_CMD_WRITE ||

@@ -232,12 +233,11 @@ static int nbd_co_request(BlockDriverState *bs,
     ret = nbd_co_send_request(bs, request,
                               request->type == NBD_CMD_WRITE ? qiov : NULL);
     if (ret < 0) {
-        reply.error = -ret;
-    } else {
-        nbd_co_receive_reply(client, request, &reply,
-                             request->type == NBD_CMD_READ ? qiov : NULL);
+        return ret;
     }
-    return -reply.error;
+
+    return nbd_co_receive_reply(client, request,
+                                request->type == NBD_CMD_READ ? qiov : NULL);
 }
 
 int nbd_client_co_preadv(BlockDriverState *bs, uint64_t offset,
Signature · 1 line
2.11.1
author
#2 lore raw

PATCH v3 2/3 block/nbd-client: simplify check in nbd_co_receive_reply

In reply to Vladimir Sementsov-Ogievskiy

If we are woken up from while() loop in nbd_read_reply_entry handles must be equal. If we are woken up from nbd_recv_coroutines_wake_all s->quit must be true, so we do not need checking handles equality.

Signed-off-by Vladimir Sementsov-Ogievskiy <[email protected]>
---
 block/nbd-client.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)
block/nbd-client.c +2 -1
index acd8e5d007..486bfff9f7 100644
@@ -189,9 +189,10 @@ static int nbd_co_receive_reply(NBDClientSession *s,
     s->requests[i].receiving = true;
     qemu_coroutine_yield();
     s->requests[i].receiving = false;
-    if (s->reply.handle != request->handle || !s->ioc || s->quit) {
+    if (!s->ioc || s->quit) {
         ret = -EIO;
     } else {
+        assert(s->reply.handle == request->handle);
         ret = -s->reply.error;
         if (qiov && s->reply.error == 0) {
             assert(request->len == iov_size(qiov->iov, qiov->niov));
Signature · 1 line
2.11.1
Reviewed-by on v3 2/3
#3 lore raw

Re: [Qemu-devel] [PATCH v3 2/3] block/nbd-client: simplify check in nbd_co_receive_reply

Quoted 9 lines · Vladimir Sementsov-Ogievskiy

If we are woken up from while() loop in nbd_read_reply_entry handles must be equal. If we are woken up from nbd_recv_coroutines_wake_all s->quit must be true, so we do not need checking handles equality.

Signed-off-by Vladimir Sementsov-Ogievskiy <[email protected]>
---
 block/nbd-client.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)
Reviewed-by Eric Blake <[email protected]>
Quoted 18 lines
block/nbd-client.c +2 -1
index acd8e5d007..486bfff9f7 100644
@@ -189,9 +189,10 @@ static int nbd_co_receive_reply(NBDClientSession *s,
     s->requests[i].receiving = true;
     qemu_coroutine_yield();
     s->requests[i].receiving = false;
-    if (s->reply.handle != request->handle || !s->ioc || s->quit) {
+    if (!s->ioc || s->quit) {
         ret = -EIO;
     } else {
+        assert(s->reply.handle == request->handle);
         ret = -s->reply.error;
         if (qiov && s->reply.error == 0) {
             assert(request->len == iov_size(qiov->iov, qiov->niov));
Signature · 3 lines
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3266
Virtualization:  qemu.org | libvirt.org
author
#4 lore raw

PATCH v3 3/3 block/nbd-client: nbd_co_send_request: fix return code

In reply to Vladimir Sementsov-Ogievskiy

It's incorrect to return success rc >= 0 if we skip qio_channel_writev_all() call due to s->quit.

Signed-off-by Vladimir Sementsov-Ogievskiy <[email protected]>
---
 block/nbd-client.c | 2 ++
 1 file changed, 2 insertions(+)
block/nbd-client.c +2 -0
index 486bfff9f7..9d1e154feb 100644
@@ -161,6 +161,8 @@ static int nbd_co_send_request(BlockDriverState *bs,
                                        NULL) < 0) {
                 rc = -EIO;
             }
+        } else if (rc >= 0) {
+            rc = -EIO;
         }
         qio_channel_set_cork(s->ioc, false);
     } else {
Signature · 1 line
2.11.1
Reviewed-by on v3 3/3
#5 lore raw

Re: [Qemu-devel] [PATCH v3 3/3] block/nbd-client: nbd_co_send_request: fix return code

Quoted 7 lines · Vladimir Sementsov-Ogievskiy

It's incorrect to return success rc >= 0 if we skip qio_channel_writev_all() call due to s->quit.

Signed-off-by Vladimir Sementsov-Ogievskiy <[email protected]>
---
 block/nbd-client.c | 2 ++
 1 file changed, 2 insertions(+)
Reviewed-by Eric Blake <[email protected]>
Quoted 15 lines
block/nbd-client.c +2 -0
index 486bfff9f7..9d1e154feb 100644
@@ -161,6 +161,8 @@ static int nbd_co_send_request(BlockDriverState *bs,
                                        NULL) < 0) {
                 rc = -EIO;
             }
+        } else if (rc >= 0) {
+            rc = -EIO;
         }
         qio_channel_set_cork(s->ioc, false);
     } else {
Signature · 3 lines
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3266
Virtualization:  qemu.org | libvirt.org
#6 lore raw
In reply to Vladimir Sementsov-Ogievskiy
Quoted 7 lines · Vladimir Sementsov-Ogievskiy

v3: dropped all controversial things. I'll try to implement minimal structured reply and block status over this small residue.

Vladimir Sementsov-Ogievskiy (3):
block/nbd-client: refactor nbd_co_receive_reply block/nbd-client: simplify check in nbd_co_receive_reply block/nbd-client: nbd_co_send_request: fix return code

Thanks; queued on my NBD tree, will send pull request after a bit more time to see if it collects further reviews:
git://repo.or.cz/qemu/ericb.git nbd

Signature · 3 lines
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3266
Virtualization:  qemu.org | libvirt.org
author
#7 lore raw
Quoted 4 lines · Eric Blake
Quoted 3 lines · Vladimir Sementsov-Ogievskiy

v3: dropped all controversial things. I'll try to implement minimal structured reply and block status over this small residue.

Quoted 8 lines
Quoted 4 lines

Vladimir Sementsov-Ogievskiy (3):
block/nbd-client: refactor nbd_co_receive_reply block/nbd-client: simplify check in nbd_co_receive_reply block/nbd-client: nbd_co_send_request: fix return code

Thanks; queued on my NBD tree, will send pull request after a bit more time to see if it collects further reviews:
git://repo.or.cz/qemu/ericb.git nbd

Thank you, Eric!

Signature · 2 lines
Best regards,
Vladimir