2:22 p.m.
Peform several minor refactorings of how the list of negotiated meta
contexts is managed, to make upcoming patches easier: Promote the
internal type NBDExportMetaContexts to the public opaque type
NBDMetaContexts, and mark exp const. Use a shorter member name in
NBDClient. Hoist calls to nbd_check_meta_context() earlier in their
callers, as the number of negotiated contexts may impact the flags
exposed in regards to an export, which in turn requires a new
parameter. Drop a redundant parameter to nbd_negotiate_meta_queries.
No semantic change intended on the success path; on the failure path,
dropping context in nbd_check_meta_export even when reporting an error
is safer.
Signed-off-by: Eric Blake <eblake(a)redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov(a)yandex-team.ru>
---
v5: rebase to master, tweak commit message [Vladimir], R-b added
v4: new patch split out from v3 13/14, with smaller impact (quit
trying to separate exp outside of NBDMeataContexts)
---
include/block/nbd.h | 1 +
nbd/server.c | 55 ++++++++++++++++++++++++---------------------
2 files changed, 31 insertions(+), 25 deletions(-)
diff --git a/include/block/nbd.h b/include/block/nbd.h
index ba8724f5336..2006497f987 100644
--- a/include/block/nbd.h
+++ b/include/block/nbd.h
@@ -29,6 +29,7 @@
typedef struct NBDExport NBDExport;
typedef struct NBDClient NBDClient;
typedef struct NBDClientConnection NBDClientConnection;
+typedef struct NBDMetaContexts NBDMetaContexts;
extern const BlockExportDriver blk_exp_nbd;
diff --git a/nbd/server.c b/nbd/server.c
index b09ee44c159..44ebbd139b2 100644
--- a/nbd/server.c
+++ b/nbd/server.c
@@ -105,11 +105,13 @@ struct NBDExport {
static QTAILQ_HEAD(, NBDExport) exports = QTAILQ_HEAD_INITIALIZER(exports);
-/* NBDExportMetaContexts represents a list of contexts to be exported,
+/*
+ * NBDMetaContexts represents a list of meta contexts in use,
* as selected by NBD_OPT_SET_META_CONTEXT. Also used for
- * NBD_OPT_LIST_META_CONTEXT. */
-typedef struct NBDExportMetaContexts {
- NBDExport *exp;
+ * NBD_OPT_LIST_META_CONTEXT.
+ */
+struct NBDMetaContexts {
+ const NBDExport *exp; /* associated export */
size_t count; /* number of negotiated contexts */
bool base_allocation; /* export base:allocation context (block status) */
bool allocation_depth; /* export qemu:allocation-depth */
@@ -117,7 +119,7 @@ typedef struct NBDExportMetaContexts {
* export qemu:dirty-bitmap:<export bitmap name>,
* sized by exp->nr_export_bitmaps
*/
-} NBDExportMetaContexts;
+};
struct NBDClient {
int refcount;
@@ -144,7 +146,7 @@ struct NBDClient {
uint32_t check_align; /* If non-zero, check for aligned client requests */
NBDMode mode;
- NBDExportMetaContexts export_meta;
+ NBDMetaContexts contexts; /* Negotiated meta contexts */
uint32_t opt; /* Current option being negotiated */
uint32_t optlen; /* remaining length of data in ioc for the option being
@@ -455,10 +457,10 @@ static int nbd_negotiate_handle_list(NBDClient *client, Error
**errp)
return nbd_negotiate_send_rep(client, NBD_REP_ACK, errp);
}
-static void nbd_check_meta_export(NBDClient *client)
+static void nbd_check_meta_export(NBDClient *client, NBDExport *exp)
{
- if (client->exp != client->export_meta.exp) {
- client->export_meta.count = 0;
+ if (exp != client->contexts.exp) {
+ client->contexts.count = 0;
}
}
@@ -504,6 +506,7 @@ static int nbd_negotiate_handle_export_name(NBDClient *client, bool
no_zeroes,
error_setg(errp, "export not found");
return -EINVAL;
}
+ nbd_check_meta_export(client, client->exp);
myflags = client->exp->nbdflags;
if (client->mode >= NBD_MODE_STRUCTURED) {
@@ -521,7 +524,6 @@ static int nbd_negotiate_handle_export_name(NBDClient *client, bool
no_zeroes,
QTAILQ_INSERT_TAIL(&client->exp->clients, client, next);
blk_exp_ref(&client->exp->common);
- nbd_check_meta_export(client);
return 0;
}
@@ -641,6 +643,9 @@ static int nbd_negotiate_handle_info(NBDClient *client, Error **errp)
errp, "export '%s' not
present",
sane_name);
}
+ if (client->opt == NBD_OPT_GO) {
+ nbd_check_meta_export(client, exp);
+ }
/* Don't bother sending NBD_INFO_NAME unless client requested it */
if (sendname) {
@@ -729,7 +734,6 @@ static int nbd_negotiate_handle_info(NBDClient *client, Error **errp)
client->check_align = check_align;
QTAILQ_INSERT_TAIL(&client->exp->clients, client, next);
blk_exp_ref(&client->exp->common);
- nbd_check_meta_export(client);
rc = 1;
}
return rc;
@@ -852,7 +856,7 @@ static bool nbd_strshift(const char **str, const char *prefix)
* Handle queries to 'base' namespace. For now, only the base:allocation
* context is available. Return true if @query has been handled.
*/
-static bool nbd_meta_base_query(NBDClient *client, NBDExportMetaContexts *meta,
+static bool nbd_meta_base_query(NBDClient *client, NBDMetaContexts *meta,
const char *query)
{
if (!nbd_strshift(&query, "base:")) {
@@ -872,7 +876,7 @@ static bool nbd_meta_base_query(NBDClient *client,
NBDExportMetaContexts *meta,
* and qemu:allocation-depth contexts are available. Return true if @query
* has been handled.
*/
-static bool nbd_meta_qemu_query(NBDClient *client, NBDExportMetaContexts *meta,
+static bool nbd_meta_qemu_query(NBDClient *client, NBDMetaContexts *meta,
const char *query)
{
size_t i;
@@ -938,7 +942,7 @@ static bool nbd_meta_qemu_query(NBDClient *client,
NBDExportMetaContexts *meta,
* Return -errno on I/O error, 0 if option was completely handled by
* sending a reply about inconsistent lengths, or 1 on success. */
static int nbd_negotiate_meta_query(NBDClient *client,
- NBDExportMetaContexts *meta, Error **errp)
+ NBDMetaContexts *meta, Error **errp)
{
int ret;
g_autofree char *query = NULL;
@@ -977,14 +981,14 @@ static int nbd_negotiate_meta_query(NBDClient *client,
* Handle NBD_OPT_LIST_META_CONTEXT and NBD_OPT_SET_META_CONTEXT
*
* Return -errno on I/O error, or 0 if option was completely handled. */
-static int nbd_negotiate_meta_queries(NBDClient *client,
- NBDExportMetaContexts *meta, Error **errp)
+static int nbd_negotiate_meta_queries(NBDClient *client, Error **errp)
{
int ret;
g_autofree char *export_name = NULL;
/* Mark unused to work around https://bugs.llvm.org/show_bug.cgi?id=3888 */
g_autofree G_GNUC_UNUSED bool *bitmaps = NULL;
- NBDExportMetaContexts local_meta = {0};
+ NBDMetaContexts local_meta = {0};
+ NBDMetaContexts *meta;
uint32_t nb_queries;
size_t i;
size_t count = 0;
@@ -1000,6 +1004,8 @@ static int nbd_negotiate_meta_queries(NBDClient *client,
if (client->opt == NBD_OPT_LIST_META_CONTEXT) {
/* Only change the caller's meta on SET. */
meta = &local_meta;
+ } else {
+ meta = &client->contexts;
}
g_free(meta->bitmaps);
@@ -1284,8 +1290,7 @@ static int nbd_negotiate_options(NBDClient *client, Error **errp)
case NBD_OPT_LIST_META_CONTEXT:
case NBD_OPT_SET_META_CONTEXT:
- ret = nbd_negotiate_meta_queries(client, &client->export_meta,
- errp);
+ ret = nbd_negotiate_meta_queries(client, errp);
break;
case NBD_OPT_EXTENDED_HEADERS:
@@ -1512,7 +1517,7 @@ void nbd_client_put(NBDClient *client)
QTAILQ_REMOVE(&client->exp->clients, client, next);
blk_exp_unref(&client->exp->common);
}
- g_free(client->export_meta.bitmaps);
+ g_free(client->contexts.bitmaps);
g_free(client);
}
}
@@ -2746,11 +2751,11 @@ static coroutine_fn int nbd_handle_request(NBDClient *client,
}
assert(client->mode >= NBD_MODE_EXTENDED ||
request->len <= UINT32_MAX);
- if (client->export_meta.count) {
+ if (client->contexts.count) {
bool dont_fragment = request->flags & NBD_CMD_FLAG_REQ_ONE;
- int contexts_remaining = client->export_meta.count;
+ int contexts_remaining = client->contexts.count;
- if (client->export_meta.base_allocation) {
+ if (client->contexts.base_allocation) {
ret = nbd_co_send_block_status(client, request,
exp->common.blk,
request->from,
@@ -2763,7 +2768,7 @@ static coroutine_fn int nbd_handle_request(NBDClient *client,
}
}
- if (client->export_meta.allocation_depth) {
+ if (client->contexts.allocation_depth) {
ret = nbd_co_send_block_status(client, request,
exp->common.blk,
request->from, request->len,
@@ -2777,7 +2782,7 @@ static coroutine_fn int nbd_handle_request(NBDClient *client,
}
for (i = 0; i < client->exp->nr_export_bitmaps; i++) {
- if (!client->export_meta.bitmaps[i]) {
+ if (!client->contexts.bitmaps[i]) {
continue;
}
ret = nbd_co_send_bitmap(client, request,
--
2.41.0