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cifs: split out dfs code from cifs_reconnect()
Make two separate functions that handle dfs and non-dfs reconnect logics since cifs_reconnect() became way too complex to handle both. While at it, add some documentation. Signed-off-by: Paulo Alcantara (SUSE) <pc@cjr.nz> Reviewed-by: Shyam Prasad N <sprasad@microsoft.com> Signed-off-by: Steve French <stfrench@microsoft.com>
This commit is contained in:
Paulo Alcantara
Steve French
parent
ae0abb4dac
commit
bbcce36804
@ -148,57 +148,6 @@ static void cifs_resolve_server(struct work_struct *work)
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mutex_unlock(&server->srv_mutex);
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}
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#ifdef CONFIG_CIFS_DFS_UPCALL
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/* These functions must be called with server->srv_mutex held */
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static void reconn_set_next_dfs_target(struct TCP_Server_Info *server,
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struct cifs_sb_info *cifs_sb,
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struct dfs_cache_tgt_list *tgt_list,
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struct dfs_cache_tgt_iterator **tgt_it)
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{
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const char *name;
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int rc;
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if (!cifs_sb || !cifs_sb->origin_fullpath)
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return;
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if (!*tgt_it) {
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*tgt_it = dfs_cache_get_tgt_iterator(tgt_list);
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} else {
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*tgt_it = dfs_cache_get_next_tgt(tgt_list, *tgt_it);
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if (!*tgt_it)
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*tgt_it = dfs_cache_get_tgt_iterator(tgt_list);
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}
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cifs_dbg(FYI, "%s: UNC: %s\n", __func__, cifs_sb->origin_fullpath);
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name = dfs_cache_get_tgt_name(*tgt_it);
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kfree(server->hostname);
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server->hostname = extract_hostname(name);
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if (IS_ERR(server->hostname)) {
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cifs_dbg(FYI,
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"%s: failed to extract hostname from target: %ld\n",
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__func__, PTR_ERR(server->hostname));
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return;
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}
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rc = reconn_set_ipaddr_from_hostname(server);
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if (rc) {
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cifs_dbg(FYI, "%s: failed to resolve hostname: %d\n",
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__func__, rc);
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}
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}
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static inline int reconn_setup_dfs_targets(struct cifs_sb_info *cifs_sb,
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struct dfs_cache_tgt_list *tl)
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{
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if (!cifs_sb->origin_fullpath)
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return -EOPNOTSUPP;
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return dfs_cache_noreq_find(cifs_sb->origin_fullpath + 1, NULL, tl);
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}
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#endif
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/**
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* Mark all sessions and tcons for reconnect.
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*
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@ -278,6 +227,21 @@ static void cifs_mark_tcp_ses_conns_for_reconnect(struct TCP_Server_Info *server
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}
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}
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static bool cifs_tcp_ses_needs_reconnect(struct TCP_Server_Info *server, int num_targets)
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{
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spin_lock(&GlobalMid_Lock);
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server->nr_targets = num_targets;
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if (server->tcpStatus == CifsExiting) {
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/* the demux thread will exit normally next time through the loop */
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spin_unlock(&GlobalMid_Lock);
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wake_up(&server->response_q);
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return false;
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}
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server->tcpStatus = CifsNeedReconnect;
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spin_unlock(&GlobalMid_Lock);
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return true;
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}
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/*
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* cifs tcp session reconnection
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*
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@ -286,90 +250,23 @@ static void cifs_mark_tcp_ses_conns_for_reconnect(struct TCP_Server_Info *server
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* reconnect tcp session
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* wake up waiters on reconnection? - (not needed currently)
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*/
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int
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cifs_reconnect(struct TCP_Server_Info *server)
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static int __cifs_reconnect(struct TCP_Server_Info *server)
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{
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int rc = 0;
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#ifdef CONFIG_CIFS_DFS_UPCALL
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struct super_block *sb = NULL;
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struct cifs_sb_info *cifs_sb = NULL;
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struct dfs_cache_tgt_list tgt_list = DFS_CACHE_TGT_LIST_INIT(tgt_list);
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struct dfs_cache_tgt_iterator *tgt_it = NULL;
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#endif
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spin_lock(&GlobalMid_Lock);
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server->nr_targets = 1;
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#ifdef CONFIG_CIFS_DFS_UPCALL
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spin_unlock(&GlobalMid_Lock);
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sb = cifs_get_tcp_super(server);
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if (IS_ERR(sb)) {
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rc = PTR_ERR(sb);
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cifs_dbg(FYI, "%s: will not do DFS failover: rc = %d\n",
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__func__, rc);
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sb = NULL;
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} else {
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cifs_sb = CIFS_SB(sb);
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rc = reconn_setup_dfs_targets(cifs_sb, &tgt_list);
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if (rc) {
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cifs_sb = NULL;
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if (rc != -EOPNOTSUPP) {
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cifs_server_dbg(VFS, "%s: no target servers for DFS failover\n",
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__func__);
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}
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} else {
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server->nr_targets = dfs_cache_get_nr_tgts(&tgt_list);
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}
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}
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cifs_dbg(FYI, "%s: will retry %d target(s)\n", __func__,
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server->nr_targets);
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spin_lock(&GlobalMid_Lock);
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#endif
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if (server->tcpStatus == CifsExiting) {
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/* the demux thread will exit normally next time through the loop */
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spin_unlock(&GlobalMid_Lock);
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#ifdef CONFIG_CIFS_DFS_UPCALL
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dfs_cache_free_tgts(&tgt_list);
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cifs_put_tcp_super(sb);
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#endif
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wake_up(&server->response_q);
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return rc;
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} else
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server->tcpStatus = CifsNeedReconnect;
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spin_unlock(&GlobalMid_Lock);
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if (!cifs_tcp_ses_needs_reconnect(server, 1))
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return 0;
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cifs_mark_tcp_ses_conns_for_reconnect(server);
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do {
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try_to_freeze();
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mutex_lock(&server->srv_mutex);
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if (!cifs_swn_set_server_dstaddr(server)) {
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#ifdef CONFIG_CIFS_DFS_UPCALL
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if (cifs_sb && cifs_sb->origin_fullpath)
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/*
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* Set up next DFS target server (if any) for reconnect. If DFS
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* feature is disabled, then we will retry last server we
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* connected to before.
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*/
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reconn_set_next_dfs_target(server, cifs_sb, &tgt_list, &tgt_it);
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else {
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#endif
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/*
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* Resolve the hostname again to make sure that IP address is up-to-date.
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*/
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/* resolve the hostname again to make sure that IP address is up-to-date */
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rc = reconn_set_ipaddr_from_hostname(server);
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if (rc) {
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cifs_dbg(FYI, "%s: failed to resolve hostname: %d\n",
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__func__, rc);
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}
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#ifdef CONFIG_CIFS_DFS_UPCALL
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}
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#endif
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cifs_dbg(FYI, "%s: reconn_set_ipaddr_from_hostname: rc=%d\n", __func__, rc);
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}
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if (cifs_rdma_enabled(server))
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@ -377,8 +274,8 @@ cifs_reconnect(struct TCP_Server_Info *server)
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else
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rc = generic_ip_connect(server);
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if (rc) {
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cifs_dbg(FYI, "reconnect error %d\n", rc);
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mutex_unlock(&server->srv_mutex);
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cifs_dbg(FYI, "%s: reconnect error %d\n", __func__, rc);
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msleep(3000);
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} else {
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atomic_inc(&tcpSesReconnectCount);
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@ -392,19 +289,6 @@ cifs_reconnect(struct TCP_Server_Info *server)
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}
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} while (server->tcpStatus == CifsNeedReconnect);
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#ifdef CONFIG_CIFS_DFS_UPCALL
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if (tgt_it) {
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rc = dfs_cache_noreq_update_tgthint(cifs_sb->origin_fullpath + 1,
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tgt_it);
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if (rc) {
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cifs_server_dbg(VFS, "%s: failed to update DFS target hint: rc = %d\n",
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__func__, rc);
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}
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dfs_cache_free_tgts(&tgt_list);
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}
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cifs_put_tcp_super(sb);
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#endif
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if (server->tcpStatus == CifsNeedNegotiate)
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mod_delayed_work(cifsiod_wq, &server->echo, 0);
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@ -412,6 +296,151 @@ cifs_reconnect(struct TCP_Server_Info *server)
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return rc;
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}
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#ifdef CONFIG_CIFS_DFS_UPCALL
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static int reconnect_dfs_server(struct TCP_Server_Info *server, struct cifs_sb_info *cifs_sb)
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{
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int rc = 0;
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const char *refpath = cifs_sb->origin_fullpath + 1;
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struct dfs_cache_tgt_list tl = DFS_CACHE_TGT_LIST_INIT(tl);
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struct dfs_cache_tgt_iterator *tit = NULL;
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int num_targets = 1;
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char *hostname;
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/*
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* Determine the number of dfs targets the referral path in @cifs_sb resolves to.
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*
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* smb2_reconnect() needs to know how long it should wait based upon the number of dfs
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* targets (server->nr_targets). It's also possible that the cached referral was cleared
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* through /proc/fs/cifs/dfscache or the target list is empty due to server settings after
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* refreshing the referral, so, in this case, default it to 1.
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*/
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if (!dfs_cache_noreq_find(refpath, NULL, &tl)) {
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num_targets = dfs_cache_get_nr_tgts(&tl);
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if (!num_targets)
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num_targets = 1;
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}
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if (!cifs_tcp_ses_needs_reconnect(server, num_targets))
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return 0;
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cifs_mark_tcp_ses_conns_for_reconnect(server);
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do {
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/* Get next dfs target from target list (if any) */
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if (!tit)
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tit = dfs_cache_get_tgt_iterator(&tl);
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else
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tit = dfs_cache_get_next_tgt(&tl, tit);
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try_to_freeze();
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mutex_lock(&server->srv_mutex);
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if (!cifs_swn_set_server_dstaddr(server)) {
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/*
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* If any dfs target was selected, then update @server with either a
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* hostname or an address.
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*/
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if (tit) {
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hostname = extract_hostname(dfs_cache_get_tgt_name(tit));
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if (!IS_ERR(hostname)) {
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kfree(server->hostname);
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server->hostname = hostname;
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} else {
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cifs_dbg(FYI, "%s: couldn't extract hostname or address from dfs target: %ld\n",
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__func__, PTR_ERR(hostname));
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cifs_dbg(FYI, "%s: default to last target server: %s\n",
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__func__, server->hostname);
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}
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}
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/* resolve the hostname again to make sure that IP address is up-to-date. */
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rc = reconn_set_ipaddr_from_hostname(server);
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cifs_dbg(FYI, "%s: reconn_set_ipaddr_from_hostname: rc=%d\n", __func__, rc);
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}
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/* Reconnect the socket */
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if (cifs_rdma_enabled(server))
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rc = smbd_reconnect(server);
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else
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rc = generic_ip_connect(server);
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if (rc) {
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/* Failed to reconnect socket. Retry next dfs target. */
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mutex_unlock(&server->srv_mutex);
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cifs_dbg(FYI, "%s: reconnect error %d\n", __func__, rc);
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msleep(3000);
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continue;
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}
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/*
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* Socket was created. Update tcp session status to CifsNeedNegotiate so that a
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* process waiting for reconnect will know it needs to re-establish session and tcon
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* through the reconnected target server.
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*/
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atomic_inc(&tcpSesReconnectCount);
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set_credits(server, 1);
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spin_lock(&GlobalMid_Lock);
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if (server->tcpStatus != CifsExiting)
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server->tcpStatus = CifsNeedNegotiate;
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spin_unlock(&GlobalMid_Lock);
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cifs_swn_reset_server_dstaddr(server);
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mutex_unlock(&server->srv_mutex);
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} while (server->tcpStatus == CifsNeedReconnect);
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if (tit)
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dfs_cache_noreq_update_tgthint(refpath, tit);
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dfs_cache_free_tgts(&tl);
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/* Need to set up echo worker again once connection has been established */
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if (server->tcpStatus == CifsNeedNegotiate)
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mod_delayed_work(cifsiod_wq, &server->echo, 0);
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wake_up(&server->response_q);
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return rc;
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}
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int cifs_reconnect(struct TCP_Server_Info *server)
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{
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int rc;
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struct super_block *sb;
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struct cifs_sb_info *cifs_sb;
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/*
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* If tcp session is not an dfs connection or it is a channel, then reconnect to last target
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* server.
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*/
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spin_lock(&cifs_tcp_ses_lock);
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if (!server->is_dfs_conn || server->is_channel) {
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spin_unlock(&cifs_tcp_ses_lock);
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return __cifs_reconnect(server);
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}
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spin_unlock(&cifs_tcp_ses_lock);
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/* If no superblock, then it might be an ipc connection */
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sb = cifs_get_tcp_super(server);
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if (IS_ERR(sb))
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return __cifs_reconnect(server);
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/*
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* Check for a referral path to look up in superblock. If unset, then simply reconnect to
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* last target server.
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*/
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cifs_sb = CIFS_SB(sb);
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if (!cifs_sb->origin_fullpath || !cifs_sb->origin_fullpath[0])
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rc = __cifs_reconnect(server);
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else
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rc = reconnect_dfs_server(server, cifs_sb);
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cifs_put_tcp_super(sb);
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return rc;
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}
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#else
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int cifs_reconnect(struct TCP_Server_Info *server)
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{
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return __cifs_reconnect(server);
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}
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#endif
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static void
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cifs_echo_request(struct work_struct *work)
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{
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