nbd: BLOCK_STATUS for standard get_block_status function: server part
Minimal realization: only one extent in server answer is supported. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Message-Id: <20180312152126.286890-4-vsementsov@virtuozzo.com> Reviewed-by: Eric Blake <eblake@redhat.com> [eblake: tweak whitespace, move constant from .h to .c, improve logic of check_meta_export_name, simplify nbd_negotiate_options by doing more in nbd_negotiate_meta_queries] Signed-off-by: Eric Blake <eblake@redhat.com>
This commit is contained in:
Vladimir Sementsov-Ogievskiy
Eric Blake
parent
12296459f4
commit
e7b1948d51
311
nbd/server.c
311
nbd/server.c
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@ -22,6 +22,8 @@
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#include "trace.h"
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#include "nbd-internal.h"
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#define NBD_META_ID_BASE_ALLOCATION 0
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static int system_errno_to_nbd_errno(int err)
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{
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switch (err) {
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@ -82,6 +84,16 @@ struct NBDExport {
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static QTAILQ_HEAD(, NBDExport) exports = QTAILQ_HEAD_INITIALIZER(exports);
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/* NBDExportMetaContexts represents a list of contexts to be exported,
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* as selected by NBD_OPT_SET_META_CONTEXT. Also used for
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* NBD_OPT_LIST_META_CONTEXT. */
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typedef struct NBDExportMetaContexts {
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char export_name[NBD_MAX_NAME_SIZE + 1];
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bool valid; /* means that negotiation of the option finished without
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errors */
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bool base_allocation; /* export base:allocation context (block status) */
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} NBDExportMetaContexts;
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struct NBDClient {
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int refcount;
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void (*close_fn)(NBDClient *client, bool negotiated);
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@ -102,6 +114,7 @@ struct NBDClient {
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bool closing;
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bool structured_reply;
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NBDExportMetaContexts export_meta;
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uint32_t opt; /* Current option being negotiated */
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uint32_t optlen; /* remaining length of data in ioc for the option being
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@ -273,6 +286,20 @@ static int nbd_opt_read(NBDClient *client, void *buffer, size_t size,
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return qio_channel_read_all(client->ioc, buffer, size, errp) < 0 ? -EIO : 1;
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}
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/* Drop size bytes from the unparsed payload of the current option.
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* Return -errno on I/O error, 0 if option was completely handled by
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* sending a reply about inconsistent lengths, or 1 on success. */
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static int nbd_opt_skip(NBDClient *client, size_t size, Error **errp)
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{
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if (size > client->optlen) {
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return nbd_opt_invalid(client, errp,
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"Inconsistent lengths in option %s",
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nbd_opt_lookup(client->opt));
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}
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client->optlen -= size;
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return nbd_drop(client->ioc, size, errp) < 0 ? -EIO : 1;
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}
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/* nbd_opt_read_name
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*
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* Read a string with the format:
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@ -372,6 +399,12 @@ static int nbd_negotiate_handle_list(NBDClient *client, Error **errp)
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return nbd_negotiate_send_rep(client, NBD_REP_ACK, errp);
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}
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static void nbd_check_meta_export_name(NBDClient *client)
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{
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client->export_meta.valid &= !strcmp(client->exp->name,
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client->export_meta.export_name);
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}
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/* Send a reply to NBD_OPT_EXPORT_NAME.
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* Return -errno on error, 0 on success. */
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static int nbd_negotiate_handle_export_name(NBDClient *client,
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@ -423,6 +456,7 @@ static int nbd_negotiate_handle_export_name(NBDClient *client,
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QTAILQ_INSERT_TAIL(&client->exp->clients, client, next);
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nbd_export_get(client->exp);
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nbd_check_meta_export_name(client);
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return 0;
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}
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@ -616,6 +650,7 @@ static int nbd_negotiate_handle_info(NBDClient *client, uint16_t myflags,
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client->exp = exp;
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QTAILQ_INSERT_TAIL(&client->exp->clients, client, next);
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nbd_export_get(client->exp);
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nbd_check_meta_export_name(client);
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rc = 1;
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}
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return rc;
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@ -670,6 +705,189 @@ static QIOChannel *nbd_negotiate_handle_starttls(NBDClient *client,
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return QIO_CHANNEL(tioc);
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}
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/* nbd_negotiate_send_meta_context
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*
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* Send one chunk of reply to NBD_OPT_{LIST,SET}_META_CONTEXT
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*
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* For NBD_OPT_LIST_META_CONTEXT @context_id is ignored, 0 is used instead.
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*/
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static int nbd_negotiate_send_meta_context(NBDClient *client,
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const char *context,
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uint32_t context_id,
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Error **errp)
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{
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NBDOptionReplyMetaContext opt;
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struct iovec iov[] = {
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{.iov_base = &opt, .iov_len = sizeof(opt)},
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{.iov_base = (void *)context, .iov_len = strlen(context)}
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};
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if (client->opt == NBD_OPT_LIST_META_CONTEXT) {
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context_id = 0;
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}
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set_be_option_rep(&opt.h, client->opt, NBD_REP_META_CONTEXT,
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sizeof(opt) - sizeof(opt.h) + iov[1].iov_len);
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stl_be_p(&opt.context_id, context_id);
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return qio_channel_writev_all(client->ioc, iov, 2, errp) < 0 ? -EIO : 0;
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}
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/* nbd_meta_base_query
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*
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* Handle query to 'base' namespace. For now, only base:allocation context is
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* available in it. 'len' is the amount of text remaining to be read from
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* the current name, after the 'base:' portion has been stripped.
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*
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* Return -errno on I/O error, 0 if option was completely handled by
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* sending a reply about inconsistent lengths, or 1 on success. */
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static int nbd_meta_base_query(NBDClient *client, NBDExportMetaContexts *meta,
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uint32_t len, Error **errp)
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{
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int ret;
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char query[sizeof("allocation") - 1];
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size_t alen = strlen("allocation");
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if (len == 0) {
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if (client->opt == NBD_OPT_LIST_META_CONTEXT) {
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meta->base_allocation = true;
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}
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return 1;
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}
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if (len != alen) {
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return nbd_opt_skip(client, len, errp);
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}
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ret = nbd_opt_read(client, query, len, errp);
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if (ret <= 0) {
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return ret;
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}
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if (strncmp(query, "allocation", alen) == 0) {
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meta->base_allocation = true;
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}
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return 1;
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}
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/* nbd_negotiate_meta_query
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*
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* Parse namespace name and call corresponding function to parse body of the
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* query.
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*
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* The only supported namespace now is 'base'.
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*
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* The function aims not wasting time and memory to read long unknown namespace
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* names.
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*
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* Return -errno on I/O error, 0 if option was completely handled by
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* sending a reply about inconsistent lengths, or 1 on success. */
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static int nbd_negotiate_meta_query(NBDClient *client,
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NBDExportMetaContexts *meta, Error **errp)
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{
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int ret;
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char query[sizeof("base:") - 1];
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size_t baselen = strlen("base:");
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uint32_t len;
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ret = nbd_opt_read(client, &len, sizeof(len), errp);
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if (ret <= 0) {
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return ret;
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}
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cpu_to_be32s(&len);
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/* The only supported namespace for now is 'base'. So query should start
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* with 'base:'. Otherwise, we can ignore it and skip the remainder. */
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if (len < baselen) {
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return nbd_opt_skip(client, len, errp);
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}
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len -= baselen;
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ret = nbd_opt_read(client, query, baselen, errp);
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if (ret <= 0) {
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return ret;
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}
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if (strncmp(query, "base:", baselen) != 0) {
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return nbd_opt_skip(client, len, errp);
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}
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return nbd_meta_base_query(client, meta, len, errp);
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}
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/* nbd_negotiate_meta_queries
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* Handle NBD_OPT_LIST_META_CONTEXT and NBD_OPT_SET_META_CONTEXT
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*
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* Return -errno on I/O error, or 0 if option was completely handled. */
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static int nbd_negotiate_meta_queries(NBDClient *client,
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NBDExportMetaContexts *meta, Error **errp)
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{
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int ret;
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NBDExport *exp;
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NBDExportMetaContexts local_meta;
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uint32_t nb_queries;
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int i;
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if (!client->structured_reply) {
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return nbd_opt_invalid(client, errp,
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"request option '%s' when structured reply "
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"is not negotiated",
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nbd_opt_lookup(client->opt));
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}
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if (client->opt == NBD_OPT_LIST_META_CONTEXT) {
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/* Only change the caller's meta on SET. */
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meta = &local_meta;
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}
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memset(meta, 0, sizeof(*meta));
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ret = nbd_opt_read_name(client, meta->export_name, NULL, errp);
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if (ret <= 0) {
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return ret;
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}
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exp = nbd_export_find(meta->export_name);
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if (exp == NULL) {
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return nbd_opt_drop(client, NBD_REP_ERR_UNKNOWN, errp,
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"export '%s' not present", meta->export_name);
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}
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ret = nbd_opt_read(client, &nb_queries, sizeof(nb_queries), errp);
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if (ret <= 0) {
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return ret;
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}
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cpu_to_be32s(&nb_queries);
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if (client->opt == NBD_OPT_LIST_META_CONTEXT && !nb_queries) {
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/* enable all known contexts */
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meta->base_allocation = true;
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} else {
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for (i = 0; i < nb_queries; ++i) {
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ret = nbd_negotiate_meta_query(client, meta, errp);
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if (ret <= 0) {
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return ret;
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}
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}
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}
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if (meta->base_allocation) {
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ret = nbd_negotiate_send_meta_context(client, "base:allocation",
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NBD_META_ID_BASE_ALLOCATION,
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errp);
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if (ret < 0) {
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return ret;
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}
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}
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ret = nbd_negotiate_send_rep(client, NBD_REP_ACK, errp);
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if (ret == 0) {
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meta->valid = true;
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}
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return ret;
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}
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/* nbd_negotiate_options
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* Process all NBD_OPT_* client option commands, during fixed newstyle
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* negotiation.
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@ -860,6 +1078,12 @@ static int nbd_negotiate_options(NBDClient *client, uint16_t myflags,
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}
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break;
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case NBD_OPT_LIST_META_CONTEXT:
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case NBD_OPT_SET_META_CONTEXT:
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ret = nbd_negotiate_meta_queries(client, &client->export_meta,
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errp);
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break;
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default:
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ret = nbd_opt_drop(client, NBD_REP_ERR_UNSUP, errp,
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"Unsupported option %" PRIu32 " (%s)",
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@ -1489,6 +1713,79 @@ static int coroutine_fn nbd_co_send_sparse_read(NBDClient *client,
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return ret;
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}
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static int blockstatus_to_extent_be(BlockDriverState *bs, uint64_t offset,
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uint64_t bytes, NBDExtent *extent)
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{
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uint64_t remaining_bytes = bytes;
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while (remaining_bytes) {
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uint32_t flags;
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int64_t num;
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int ret = bdrv_block_status_above(bs, NULL, offset, remaining_bytes,
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&num, NULL, NULL);
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if (ret < 0) {
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return ret;
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}
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flags = (ret & BDRV_BLOCK_ALLOCATED ? 0 : NBD_STATE_HOLE) |
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(ret & BDRV_BLOCK_ZERO ? NBD_STATE_ZERO : 0);
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if (remaining_bytes == bytes) {
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extent->flags = flags;
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}
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if (flags != extent->flags) {
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break;
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}
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offset += num;
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remaining_bytes -= num;
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}
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cpu_to_be32s(&extent->flags);
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extent->length = cpu_to_be32(bytes - remaining_bytes);
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return 0;
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}
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/* nbd_co_send_extents
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* @extents should be in big-endian */
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static int nbd_co_send_extents(NBDClient *client, uint64_t handle,
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NBDExtent *extents, unsigned nb_extents,
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uint32_t context_id, Error **errp)
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{
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NBDStructuredMeta chunk;
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struct iovec iov[] = {
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{.iov_base = &chunk, .iov_len = sizeof(chunk)},
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{.iov_base = extents, .iov_len = nb_extents * sizeof(extents[0])}
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};
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set_be_chunk(&chunk.h, NBD_REPLY_FLAG_DONE, NBD_REPLY_TYPE_BLOCK_STATUS,
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handle, sizeof(chunk) - sizeof(chunk.h) + iov[1].iov_len);
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stl_be_p(&chunk.context_id, context_id);
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return nbd_co_send_iov(client, iov, 2, errp);
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}
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/* Get block status from the exported device and send it to the client */
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static int nbd_co_send_block_status(NBDClient *client, uint64_t handle,
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BlockDriverState *bs, uint64_t offset,
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uint64_t length, uint32_t context_id,
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Error **errp)
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{
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int ret;
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NBDExtent extent;
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ret = blockstatus_to_extent_be(bs, offset, length, &extent);
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if (ret < 0) {
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return nbd_co_send_structured_error(
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client, handle, -ret, "can't get block status", errp);
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}
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return nbd_co_send_extents(client, handle, &extent, 1, context_id, errp);
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}
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/* nbd_co_receive_request
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* Collect a client request. Return 0 if request looks valid, -EIO to drop
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* connection right away, and any other negative value to report an error to
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@ -1566,6 +1863,8 @@ static int nbd_co_receive_request(NBDRequestData *req, NBDRequest *request,
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valid_flags |= NBD_CMD_FLAG_DF;
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} else if (request->type == NBD_CMD_WRITE_ZEROES) {
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valid_flags |= NBD_CMD_FLAG_NO_HOLE;
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} else if (request->type == NBD_CMD_BLOCK_STATUS) {
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valid_flags |= NBD_CMD_FLAG_REQ_ONE;
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}
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if (request->flags & ~valid_flags) {
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error_setg(errp, "unsupported flags for command %s (got 0x%x)",
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@ -1699,6 +1998,18 @@ static coroutine_fn int nbd_handle_request(NBDClient *client,
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return nbd_send_generic_reply(client, request->handle, ret,
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"discard failed", errp);
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case NBD_CMD_BLOCK_STATUS:
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if (client->export_meta.valid && client->export_meta.base_allocation) {
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return nbd_co_send_block_status(client, request->handle,
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blk_bs(exp->blk), request->from,
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request->len,
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NBD_META_ID_BASE_ALLOCATION, errp);
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} else {
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return nbd_send_generic_reply(client, request->handle, -EINVAL,
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"CMD_BLOCK_STATUS not negotiated",
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errp);
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}
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default:
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msg = g_strdup_printf("invalid request type (%" PRIu32 ") received",
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request->type);
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