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nbd/server: Refactor list of negotiated meta contexts

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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@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
Message-ID: <20230925192229.3186470-24-eblake@redhat.com>
This commit is contained in:
Eric Blake 2023-09-25 14:22:40 -05:00
parent 56cf9d0471
commit fd358d8390
2 changed files with 31 additions and 25 deletions
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1
include/block/nbd.h
View file

@ -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;

55
nbd/server.c
View file

@ -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);
}
}
@ -2749,11 +2754,11 @@ 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,
@ -2766,7 +2771,7 @@ 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,
@ -2780,7 +2785,7 @@ 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,