@@ -391,7 +391,7 @@ static inline int reconn_set_ipaddr(struct TCP_Server_Info *server)
391391#ifdef CONFIG_CIFS_DFS_UPCALL
392392struct super_cb_data {
393393 struct TCP_Server_Info * server ;
394- struct cifs_sb_info * cifs_sb ;
394+ struct super_block * sb ;
395395};
396396
397397/* These functions must be called with server->srv_mutex held */
@@ -402,25 +402,39 @@ static void super_cb(struct super_block *sb, void *arg)
402402 struct cifs_sb_info * cifs_sb ;
403403 struct cifs_tcon * tcon ;
404404
405- if (d -> cifs_sb )
405+ if (d -> sb )
406406 return ;
407407
408408 cifs_sb = CIFS_SB (sb );
409409 tcon = cifs_sb_master_tcon (cifs_sb );
410410 if (tcon -> ses -> server == d -> server )
411- d -> cifs_sb = cifs_sb ;
411+ d -> sb = sb ;
412412}
413413
414- static inline struct cifs_sb_info *
415- find_super_by_tcp (struct TCP_Server_Info * server )
414+ static struct super_block * get_tcp_super (struct TCP_Server_Info * server )
416415{
417416 struct super_cb_data d = {
418417 .server = server ,
419- .cifs_sb = NULL ,
418+ .sb = NULL ,
420419 };
421420
422421 iterate_supers_type (& cifs_fs_type , super_cb , & d );
423- return d .cifs_sb ? d .cifs_sb : ERR_PTR (- ENOENT );
422+
423+ if (unlikely (!d .sb ))
424+ return ERR_PTR (- ENOENT );
425+ /*
426+ * Grab an active reference in order to prevent automounts (DFS links)
427+ * of expiring and then freeing up our cifs superblock pointer while
428+ * we're doing failover.
429+ */
430+ cifs_sb_active (d .sb );
431+ return d .sb ;
432+ }
433+
434+ static inline void put_tcp_super (struct super_block * sb )
435+ {
436+ if (!IS_ERR_OR_NULL (sb ))
437+ cifs_sb_deactive (sb );
424438}
425439
426440static void reconn_inval_dfs_target (struct TCP_Server_Info * server ,
@@ -484,6 +498,7 @@ cifs_reconnect(struct TCP_Server_Info *server)
484498 struct mid_q_entry * mid_entry ;
485499 struct list_head retry_list ;
486500#ifdef CONFIG_CIFS_DFS_UPCALL
501+ struct super_block * sb = NULL ;
487502 struct cifs_sb_info * cifs_sb = NULL ;
488503 struct dfs_cache_tgt_list tgt_list = {0 };
489504 struct dfs_cache_tgt_iterator * tgt_it = NULL ;
@@ -493,13 +508,15 @@ cifs_reconnect(struct TCP_Server_Info *server)
493508 server -> nr_targets = 1 ;
494509#ifdef CONFIG_CIFS_DFS_UPCALL
495510 spin_unlock (& GlobalMid_Lock );
496- cifs_sb = find_super_by_tcp (server );
497- if (IS_ERR (cifs_sb )) {
498- rc = PTR_ERR (cifs_sb );
511+ sb = get_tcp_super (server );
512+ if (IS_ERR (sb )) {
513+ rc = PTR_ERR (sb );
499514 cifs_dbg (FYI , "%s: will not do DFS failover: rc = %d\n" ,
500515 __func__ , rc );
501- cifs_sb = NULL ;
516+ sb = NULL ;
502517 } else {
518+ cifs_sb = CIFS_SB (sb );
519+
503520 rc = reconn_setup_dfs_targets (cifs_sb , & tgt_list , & tgt_it );
504521 if (rc && (rc != - EOPNOTSUPP )) {
505522 cifs_server_dbg (VFS , "%s: no target servers for DFS failover\n" ,
@@ -516,6 +533,10 @@ cifs_reconnect(struct TCP_Server_Info *server)
516533 /* the demux thread will exit normally
517534 next time through the loop */
518535 spin_unlock (& GlobalMid_Lock );
536+ #ifdef CONFIG_CIFS_DFS_UPCALL
537+ dfs_cache_free_tgts (& tgt_list );
538+ put_tcp_super (sb );
539+ #endif
519540 return rc ;
520541 } else
521542 server -> tcpStatus = CifsNeedReconnect ;
@@ -642,7 +663,10 @@ cifs_reconnect(struct TCP_Server_Info *server)
642663 __func__ , rc );
643664 }
644665 dfs_cache_free_tgts (& tgt_list );
666+
645667 }
668+
669+ put_tcp_super (sb );
646670#endif
647671 if (server -> tcpStatus == CifsNeedNegotiate )
648672 mod_delayed_work (cifsiod_wq , & server -> echo , 0 );
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