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[Qemu-devel] [PULL 09/27] nbd: Add qemu-nbd -D for human-readable descri
From: |
Paolo Bonzini |
Subject: |
[Qemu-devel] [PULL 09/27] nbd: Add qemu-nbd -D for human-readable description |
Date: |
Mon, 31 Oct 2016 15:37:25 +0100 |
From: Eric Blake <address@hidden>
The NBD protocol allows servers to advertise a human-readable
description alongside an export name during NBD_OPT_LIST. Add
an option to pass through the user's string to the NBD client.
Doing this also makes it easier to test commit 200650d4, which
is the client counterpart of receiving the description.
Signed-off-by: Eric Blake <address@hidden>
Message-Id: <address@hidden>
Signed-off-by: Paolo Bonzini <address@hidden>
---
include/block/nbd.h | 1 +
nbd/nbd-internal.h | 5 +++--
nbd/server.c | 34 ++++++++++++++++++++++++++--------
qemu-nbd.c | 12 +++++++++++-
qemu-nbd.texi | 5 ++++-
5 files changed, 45 insertions(+), 12 deletions(-)
diff --git a/include/block/nbd.h b/include/block/nbd.h
index 80610ff..fd58390 100644
--- a/include/block/nbd.h
+++ b/include/block/nbd.h
@@ -115,6 +115,7 @@ BlockBackend *nbd_export_get_blockdev(NBDExport *exp);
NBDExport *nbd_export_find(const char *name);
void nbd_export_set_name(NBDExport *exp, const char *name);
+void nbd_export_set_description(NBDExport *exp, const char *description);
void nbd_export_close_all(void);
void nbd_client_new(NBDExport *exp,
diff --git a/nbd/nbd-internal.h b/nbd/nbd-internal.h
index 93a6ca8..7e78064 100644
--- a/nbd/nbd-internal.h
+++ b/nbd/nbd-internal.h
@@ -104,9 +104,10 @@ static inline ssize_t read_sync(QIOChannel *ioc, void
*buffer, size_t size)
return nbd_wr_syncv(ioc, &iov, 1, size, true);
}
-static inline ssize_t write_sync(QIOChannel *ioc, void *buffer, size_t size)
+static inline ssize_t write_sync(QIOChannel *ioc, const void *buffer,
+ size_t size)
{
- struct iovec iov = { .iov_base = buffer, .iov_len = size };
+ struct iovec iov = { .iov_base = (void *) buffer, .iov_len = size };
return nbd_wr_syncv(ioc, &iov, 1, size, false);
}
diff --git a/nbd/server.c b/nbd/server.c
index 36bcafc..ac42391 100644
--- a/nbd/server.c
+++ b/nbd/server.c
@@ -61,6 +61,7 @@ struct NBDExport {
BlockBackend *blk;
char *name;
+ char *description;
off_t dev_offset;
off_t size;
uint16_t nbdflags;
@@ -129,7 +130,8 @@ static ssize_t nbd_negotiate_read(QIOChannel *ioc, void
*buffer, size_t size)
}
-static ssize_t nbd_negotiate_write(QIOChannel *ioc, void *buffer, size_t size)
+static ssize_t nbd_negotiate_write(QIOChannel *ioc, const void *buffer,
+ size_t size)
{
ssize_t ret;
guint watch;
@@ -225,11 +227,15 @@ static int nbd_negotiate_send_rep(QIOChannel *ioc,
uint32_t type, uint32_t opt)
static int nbd_negotiate_send_rep_list(QIOChannel *ioc, NBDExport *exp)
{
- uint64_t magic, name_len;
+ uint64_t magic;
+ size_t name_len, desc_len;
uint32_t opt, type, len;
+ const char *name = exp->name ? exp->name : "";
+ const char *desc = exp->description ? exp->description : "";
- TRACE("Advertising export name '%s'", exp->name ? exp->name : "");
- name_len = strlen(exp->name);
+ TRACE("Advertising export name '%s' description '%s'", name, desc);
+ name_len = strlen(name);
+ desc_len = strlen(desc);
magic = cpu_to_be64(NBD_REP_MAGIC);
if (nbd_negotiate_write(ioc, &magic, sizeof(magic)) != sizeof(magic)) {
LOG("write failed (magic)");
@@ -245,18 +251,22 @@ static int nbd_negotiate_send_rep_list(QIOChannel *ioc,
NBDExport *exp)
LOG("write failed (reply type)");
return -EINVAL;
}
- len = cpu_to_be32(name_len + sizeof(len));
+ len = cpu_to_be32(name_len + desc_len + sizeof(len));
if (nbd_negotiate_write(ioc, &len, sizeof(len)) != sizeof(len)) {
LOG("write failed (length)");
return -EINVAL;
}
len = cpu_to_be32(name_len);
if (nbd_negotiate_write(ioc, &len, sizeof(len)) != sizeof(len)) {
- LOG("write failed (length)");
+ LOG("write failed (name length)");
+ return -EINVAL;
+ }
+ if (nbd_negotiate_write(ioc, name, name_len) != name_len) {
+ LOG("write failed (name buffer)");
return -EINVAL;
}
- if (nbd_negotiate_write(ioc, exp->name, name_len) != name_len) {
- LOG("write failed (buffer)");
+ if (nbd_negotiate_write(ioc, desc, desc_len) != desc_len) {
+ LOG("write failed (description buffer)");
return -EINVAL;
}
return 0;
@@ -894,6 +904,12 @@ void nbd_export_set_name(NBDExport *exp, const char *name)
nbd_export_put(exp);
}
+void nbd_export_set_description(NBDExport *exp, const char *description)
+{
+ g_free(exp->description);
+ exp->description = g_strdup(description);
+}
+
void nbd_export_close(NBDExport *exp)
{
NBDClient *client, *next;
@@ -903,6 +919,7 @@ void nbd_export_close(NBDExport *exp)
client_close(client);
}
nbd_export_set_name(exp, NULL);
+ nbd_export_set_description(exp, NULL);
nbd_export_put(exp);
}
@@ -921,6 +938,7 @@ void nbd_export_put(NBDExport *exp)
if (--exp->refcount == 0) {
assert(exp->name == NULL);
+ assert(exp->description == NULL);
if (exp->close) {
exp->close(exp);
diff --git a/qemu-nbd.c b/qemu-nbd.c
index b757dc7..c734f62 100644
--- a/qemu-nbd.c
+++ b/qemu-nbd.c
@@ -83,6 +83,7 @@ static void usage(const char *name)
" -t, --persistent don't exit on the last connection\n"
" -v, --verbose display extra debugging information\n"
" -x, --export-name=NAME expose export by name\n"
+" -D, --description=TEXT with -x, also export a human-readable
description\n"
"\n"
"Exposing part of the image:\n"
" -o, --offset=OFFSET offset into the image\n"
@@ -477,7 +478,7 @@ int main(int argc, char **argv)
off_t fd_size;
QemuOpts *sn_opts = NULL;
const char *sn_id_or_name = NULL;
- const char *sopt = "hVb:o:p:rsnP:c:dvk:e:f:tl:x:T:";
+ const char *sopt = "hVb:o:p:rsnP:c:dvk:e:f:tl:x:T:D:";
struct option lopt[] = {
{ "help", no_argument, NULL, 'h' },
{ "version", no_argument, NULL, 'V' },
@@ -503,6 +504,7 @@ int main(int argc, char **argv)
{ "verbose", no_argument, NULL, 'v' },
{ "object", required_argument, NULL, QEMU_NBD_OPT_OBJECT },
{ "export-name", required_argument, NULL, 'x' },
+ { "description", required_argument, NULL, 'D' },
{ "tls-creds", required_argument, NULL, QEMU_NBD_OPT_TLSCREDS },
{ "image-opts", no_argument, NULL, QEMU_NBD_OPT_IMAGE_OPTS },
{ "trace", required_argument, NULL, 'T' },
@@ -524,6 +526,7 @@ int main(int argc, char **argv)
BlockdevDetectZeroesOptions detect_zeroes =
BLOCKDEV_DETECT_ZEROES_OPTIONS_OFF;
QDict *options = NULL;
const char *export_name = NULL;
+ const char *export_description = NULL;
const char *tlscredsid = NULL;
bool imageOpts = false;
bool writethrough = true;
@@ -689,6 +692,9 @@ int main(int argc, char **argv)
case 'x':
export_name = optarg;
break;
+ case 'D':
+ export_description = optarg;
+ break;
case 'v':
verbose = 1;
break;
@@ -937,7 +943,11 @@ int main(int argc, char **argv)
}
if (export_name) {
nbd_export_set_name(exp, export_name);
+ nbd_export_set_description(exp, export_description);
newproto = true;
+ } else if (export_description) {
+ error_report("Export description requires an export name");
+ exit(EXIT_FAILURE);
}
server_ioc = qio_channel_socket_new();
diff --git a/qemu-nbd.texi b/qemu-nbd.texi
index b7a9c6d..9a84e81 100644
--- a/qemu-nbd.texi
+++ b/qemu-nbd.texi
@@ -79,9 +79,12 @@ Disconnect the device @var{dev}
Allow up to @var{num} clients to share the device (default @samp{1})
@item -t, --persistent
Don't exit on the last connection
address@hidden -x NAME, --export-name=NAME
address@hidden -x, address@hidden
Set the NBD volume export name. This switches the server to use
the new style NBD protocol negotiation
address@hidden -D, address@hidden
+Set the NBD volume export description, as a human-readable
+string. Requires the use of @option{-x}
@item --tls-creds=ID
Enable mandatory TLS encryption for the server by setting the ID
of the TLS credentials object previously created with the --object
--
2.7.4
- [Qemu-devel] [PULL 01/27] checkpatch: tweak "struct should normally be const" warning, (continued)
- [Qemu-devel] [PULL 01/27] checkpatch: tweak "struct should normally be const" warning, Paolo Bonzini, 2016/10/31
- [Qemu-devel] [PULL 03/27] qemu-error: remove dependency of stubs on monitor, Paolo Bonzini, 2016/10/31
- [Qemu-devel] [PULL 02/27] nbd: Use CoQueue for free_sema instead of CoMutex, Paolo Bonzini, 2016/10/31
- [Qemu-devel] [PULL 04/27] tests: send error_report to test log, Paolo Bonzini, 2016/10/31
- [Qemu-devel] [PULL 06/27] exec.c: do not truncate non-empty memory backend file, Paolo Bonzini, 2016/10/31
- [Qemu-devel] [PULL 05/27] exec.c: ensure all AddressSpaceDispatch updates under RCU, Paolo Bonzini, 2016/10/31
- [Qemu-devel] [PULL 08/27] hostmem-file: make option 'size' optional, Paolo Bonzini, 2016/10/31
- [Qemu-devel] [PULL 09/27] nbd: Add qemu-nbd -D for human-readable description,
Paolo Bonzini <=
- [Qemu-devel] [PULL 07/27] exec.c: check memory backend file size with 'size' option, Paolo Bonzini, 2016/10/31
- [Qemu-devel] [PULL 11/27] nbd: Rename NBDRequest to NBDRequestData, Paolo Bonzini, 2016/10/31
- [Qemu-devel] [PULL 10/27] nbd: Treat flags vs. command type as separate fields, Paolo Bonzini, 2016/10/31
- [Qemu-devel] [PULL 12/27] nbd: Rename NbdClientSession to NBDClientSession, Paolo Bonzini, 2016/10/31
- [Qemu-devel] [PULL 14/27] nbd: Share common reply-sending code in server, Paolo Bonzini, 2016/10/31
- [Qemu-devel] [PULL 13/27] nbd: Rename struct nbd_request and nbd_reply, Paolo Bonzini, 2016/10/31
- [Qemu-devel] [PULL 15/27] nbd: Send message along with server NBD_REP_ERR errors, Paolo Bonzini, 2016/10/31
- [Qemu-devel] [PULL 17/27] nbd: Let server know when client gives up negotiation, Paolo Bonzini, 2016/10/31
- [Qemu-devel] [PULL 19/27] nbd: Less allocation during NBD_OPT_LIST, Paolo Bonzini, 2016/10/31
- [Qemu-devel] [PULL 21/27] nbd: Refactor conversion to errno to silence checkpatch, Paolo Bonzini, 2016/10/31