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[Qemu-devel] [PULL 04/14] nbd: Permit simple error to NBD_CMD_BLOCK_STAT
From: |
Eric Blake |
Subject: |
[Qemu-devel] [PULL 04/14] nbd: Permit simple error to NBD_CMD_BLOCK_STATUS |
Date: |
Mon, 1 Apr 2019 09:08:53 -0500 |
The NBD spec is clear that when structured replies are active, a
simple error reply is acceptable to any command except for
NBD_CMD_READ. However, we were mistakenly requiring structured errors
for NBD_CMD_BLOCK_STATUS, and hanging up on a server that gave a
simple error (since qemu does not behave as such a server, we didn't
notice the problem until now). Broken since its introduction in
commit 78a33ab5 (v2.12).
Noticed while debugging a separate failure reported by nbdkit while
working out its initial implementation of BLOCK_STATUS, although it
turns out that nbdkit also chose to send structured error replies for
BLOCK_STATUS, so I had to manually provoke the situation by hacking
qemu's server to send a simple error reply:
| diff --git i/nbd/server.c w/nbd/server.c
| index fd013a2817a..833288d7c45 100644
| 00--- i/nbd/server.c
| +++ w/nbd/server.c
| @@ -2269,6 +2269,8 @@ static coroutine_fn int nbd_handle_request(NBDClient
*client,
| "discard failed", errp);
|
| case NBD_CMD_BLOCK_STATUS:
| + return nbd_co_send_simple_reply(client, request->handle, ENOMEM,
| + NULL, 0, errp);
| if (!request->len) {
| return nbd_send_generic_reply(client, request->handle, -EINVAL,
| "need non-zero length", errp);
|
Signed-off-by: Eric Blake <address@hidden>
Acked-by: Richard W.M. Jones <address@hidden>
Message-Id: <address@hidden>
Reviewed-by: Vladimir Sementsov-Ogievskiy <address@hidden>
---
block/nbd-client.c | 4 +---
1 file changed, 1 insertion(+), 3 deletions(-)
diff --git a/block/nbd-client.c b/block/nbd-client.c
index b37a5963013..a3b70d14004 100644
--- a/block/nbd-client.c
+++ b/block/nbd-client.c
@@ -729,9 +729,7 @@ static int
nbd_co_receive_blockstatus_reply(NBDClientSession *s,
bool received = false;
assert(!extent->length);
- NBD_FOREACH_REPLY_CHUNK(s, iter, handle, s->info.structured_reply,
- NULL, &reply, &payload)
- {
+ NBD_FOREACH_REPLY_CHUNK(s, iter, handle, false, NULL, &reply, &payload) {
int ret;
NBDStructuredReplyChunk *chunk = &reply.structured;
--
2.20.1
- [Qemu-devel] [PULL 00/14] NBD patches for 4.0-rc2, Eric Blake, 2019/04/01
- [Qemu-devel] [PULL 01/14] qemu-img: Report bdrv_block_status failures, Eric Blake, 2019/04/01
- [Qemu-devel] [PULL 03/14] nbd: Don't lose server's error to NBD_CMD_BLOCK_STATUS, Eric Blake, 2019/04/01
- [Qemu-devel] [PULL 04/14] nbd: Permit simple error to NBD_CMD_BLOCK_STATUS,
Eric Blake <=
- [Qemu-devel] [PULL 02/14] nbd: Tolerate some server non-compliance in NBD_CMD_BLOCK_STATUS, Eric Blake, 2019/04/01
- [Qemu-devel] [PULL 05/14] qemu-img: Gracefully shutdown when map can't finish, Eric Blake, 2019/04/01
- [Qemu-devel] [PULL 06/14] nbd-client: Work around server BLOCK_STATUS misalignment at EOF, Eric Blake, 2019/04/01
- [Qemu-devel] [PULL 10/14] nbd/client: Reject inaccessible tail of inconsistent server, Eric Blake, 2019/04/01
- [Qemu-devel] [PULL 11/14] nbd/client: Support qemu-img convert from unaligned size, Eric Blake, 2019/04/01
- [Qemu-devel] [PULL 08/14] nbd/client: Lower min_block for block-status, unaligned size, Eric Blake, 2019/04/01
- [Qemu-devel] [PULL 09/14] nbd/client: Report offsets in bdrv_block_status, Eric Blake, 2019/04/01
- [Qemu-devel] [PULL 07/14] iotests: Add 241 to test NBD on unaligned images, Eric Blake, 2019/04/01