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[Qemu-block] [PATCH v6 08/12] nbd/server: Include human-readable message
From: |
Eric Blake |
Subject: |
[Qemu-block] [PATCH v6 08/12] nbd/server: Include human-readable message in structured errors |
Date: |
Fri, 27 Oct 2017 12:40:33 +0200 |
The NBD spec permits including a human-readable error string if
structured replies are in force, so we might as well send the
client the message that we logged on any error.
Signed-off-by: Eric Blake <address@hidden>
Reviewed-by: Vladimir Sementsov-Ogievskiy <address@hidden>
---
v6: add R-b
v5: allow NULL msg, cast away const for ease of use [Vladimir]; send
correct length over the wire
---
nbd/server.c | 20 +++++++++++++-------
nbd/trace-events | 2 +-
2 files changed, 14 insertions(+), 8 deletions(-)
diff --git a/nbd/server.c b/nbd/server.c
index 5d6d9a2ddd..ea9fe9970f 100644
--- a/nbd/server.c
+++ b/nbd/server.c
@@ -1295,24 +1295,25 @@ static int coroutine_fn
nbd_co_send_structured_read(NBDClient *client,
static int coroutine_fn nbd_co_send_structured_error(NBDClient *client,
uint64_t handle,
uint32_t error,
+ const char *msg,
Error **errp)
{
NBDStructuredError chunk;
int nbd_err = system_errno_to_nbd_errno(error);
struct iovec iov[] = {
{.iov_base = &chunk, .iov_len = sizeof(chunk)},
- /* FIXME: Support human-readable error message */
+ {.iov_base = (char *)msg, .iov_len = msg ? strlen(msg) : 0},
};
assert(nbd_err);
trace_nbd_co_send_structured_error(handle, nbd_err,
- nbd_err_lookup(nbd_err));
+ nbd_err_lookup(nbd_err), msg ? msg :
"");
set_be_chunk(&chunk.h, NBD_REPLY_FLAG_DONE, NBD_REPLY_TYPE_ERROR, handle,
- sizeof(chunk) - sizeof(chunk.h));
+ sizeof(chunk) - sizeof(chunk.h) + iov[1].iov_len);
stl_be_p(&chunk.error, nbd_err);
- stw_be_p(&chunk.message_length, 0);
+ stw_be_p(&chunk.message_length, iov[1].iov_len);
- return nbd_co_send_iov(client, iov, 1, errp);
+ return nbd_co_send_iov(client, iov, 1 + !!iov[1].iov_len, errp);
}
/* nbd_co_receive_request
@@ -1413,6 +1414,7 @@ static coroutine_fn void nbd_trip(void *opaque)
int flags;
int reply_data_len = 0;
Error *local_err = NULL;
+ char *msg = NULL;
trace_nbd_trip();
if (client->closing) {
@@ -1529,14 +1531,17 @@ reply:
if (local_err) {
/* If we get here, local_err was not a fatal error, and should be sent
* to the client. */
+ assert(ret < 0);
+ msg = g_strdup(error_get_pretty(local_err));
error_report_err(local_err);
local_err = NULL;
}
- if (client->structured_reply && request.type == NBD_CMD_READ) {
+ if (client->structured_reply &&
+ (ret < 0 || request.type == NBD_CMD_READ)) {
if (ret < 0) {
ret = nbd_co_send_structured_error(req->client, request.handle,
- -ret, &local_err);
+ -ret, msg, &local_err);
} else {
ret = nbd_co_send_structured_read(req->client, request.handle,
request.from, req->data,
@@ -1547,6 +1552,7 @@ reply:
ret < 0 ? -ret : 0,
req->data, reply_data_len, &local_err);
}
+ g_free(msg);
if (ret < 0) {
error_prepend(&local_err, "Failed to send reply: ");
goto disconnect;
diff --git a/nbd/trace-events b/nbd/trace-events
index 6894f8bbb4..52150bd738 100644
--- a/nbd/trace-events
+++ b/nbd/trace-events
@@ -57,7 +57,7 @@ nbd_blk_aio_attached(const char *name, void *ctx) "Export %s:
Attaching clients
nbd_blk_aio_detach(const char *name, void *ctx) "Export %s: Detaching clients
from AIO context %p\n"
nbd_co_send_simple_reply(uint64_t handle, uint32_t error, const char *errname,
int len) "Send simple reply: handle = %" PRIu64 ", error = %" PRIu32 " (%s),
len = %d"
nbd_co_send_structured_read(uint64_t handle, uint64_t offset, void *data,
size_t size) "Send structured read data reply: handle = %" PRIu64 ", offset =
%" PRIu64 ", data = %p, len = %zu"
-nbd_co_send_structured_error(uint64_t handle, int err, const char *errname)
"Send structured error reply: handle = %" PRIu64 ", error = %d (%s)"
+nbd_co_send_structured_error(uint64_t handle, int err, const char *errname,
const char *msg) "Send structured error reply: handle = %" PRIu64 ", error = %d
(%s), msg = '%s'"
nbd_co_receive_request_decode_type(uint64_t handle, uint16_t type, const char
*name) "Decoding type: handle = %" PRIu64 ", type = %" PRIu16 " (%s)"
nbd_co_receive_request_payload_received(uint64_t handle, uint32_t len)
"Payload received: handle = %" PRIu64 ", len = %" PRIu32
nbd_co_receive_request_cmd_write(uint32_t len) "Reading %" PRIu32 " byte(s)"
--
2.13.6
- [Qemu-block] [PATCH v6 01/12] nbd: Include error names in trace messages, (continued)
- [Qemu-block] [PATCH v6 01/12] nbd: Include error names in trace messages, Eric Blake, 2017/10/27
- [Qemu-block] [PATCH v6 02/12] nbd: Move nbd_errno_to_system_errno() to public header, Eric Blake, 2017/10/27
- [Qemu-block] [PATCH v6 03/12] nbd: Expose constants and structs for structured read, Eric Blake, 2017/10/27
- [Qemu-block] [PATCH v6 04/12] nbd/server: Report error for write to read-only export, Eric Blake, 2017/10/27
- [Qemu-block] [PATCH v6 05/12] nbd/server: Simplify nbd_negotiate_options loop, Eric Blake, 2017/10/27
- [Qemu-block] [PATCH v6 06/12] nbd/server: Refactor zero-length option check, Eric Blake, 2017/10/27
- [Qemu-block] [PATCH v6 07/12] nbd: Minimal structured read for server, Eric Blake, 2017/10/27
- [Qemu-block] [PATCH v6 08/12] nbd/server: Include human-readable message in structured errors,
Eric Blake <=
- [Qemu-block] [PATCH v6 10/12] nbd/client: prepare nbd_receive_reply for structured reply, Eric Blake, 2017/10/27
- [Qemu-block] [PATCH v6 09/12] nbd/client: refactor nbd_receive_starttls, Eric Blake, 2017/10/27
- [Qemu-block] [PATCH v6 11/12] nbd: Move nbd_read() to common header, Eric Blake, 2017/10/27
- [Qemu-block] [PATCH v6 12/12] nbd: Minimal structured read for client, Eric Blake, 2017/10/27
- [Qemu-block] [RFC PATCH v6 13/12] tweak test 83 verbosity, Eric Blake, 2017/10/27