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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * DFS referral cache routines
4 *
5 * Copyright (c) 2018-2019 Paulo Alcantara <palcantara@suse.de>
6 */
7
8#include <linux/jhash.h>
9#include <linux/ktime.h>
10#include <linux/slab.h>
11#include <linux/proc_fs.h>
12#include <linux/nls.h>
13#include <linux/workqueue.h>
14#include <linux/uuid.h>
15#include "cifsglob.h"
16#include "smb2pdu.h"
17#include "smb2proto.h"
18#include "cifsproto.h"
19#include "cifs_debug.h"
20#include "cifs_unicode.h"
21#include "smb2glob.h"
22#include "dns_resolve.h"
23
24#include "dfs_cache.h"
25
26#define CACHE_HTABLE_SIZE 32
27#define CACHE_MAX_ENTRIES 64
28#define CACHE_MIN_TTL 120 /* 2 minutes */
29
30#define IS_DFS_INTERLINK(v) (((v) & DFSREF_REFERRAL_SERVER) && !((v) & DFSREF_STORAGE_SERVER))
31
32struct cache_dfs_tgt {
33 char *name;
34 int path_consumed;
35 struct list_head list;
36};
37
38struct cache_entry {
39 struct hlist_node hlist;
40 const char *path;
41 int hdr_flags; /* RESP_GET_DFS_REFERRAL.ReferralHeaderFlags */
42 int ttl; /* DFS_REREFERRAL_V3.TimeToLive */
43 int srvtype; /* DFS_REREFERRAL_V3.ServerType */
44 int ref_flags; /* DFS_REREFERRAL_V3.ReferralEntryFlags */
45 struct timespec64 etime;
46 int path_consumed; /* RESP_GET_DFS_REFERRAL.PathConsumed */
47 int numtgts;
48 struct list_head tlist;
49 struct cache_dfs_tgt *tgthint;
50};
51
52/* List of referral server sessions per dfs mount */
53struct mount_group {
54 struct list_head list;
55 uuid_t id;
56 struct cifs_ses *sessions[CACHE_MAX_ENTRIES];
57 int num_sessions;
58 spinlock_t lock;
59 struct list_head refresh_list;
60 struct kref refcount;
61};
62
63static struct kmem_cache *cache_slab __read_mostly;
64static struct workqueue_struct *dfscache_wq __read_mostly;
65
66static int cache_ttl;
67static DEFINE_SPINLOCK(cache_ttl_lock);
68
69static struct nls_table *cache_cp;
70
71/*
72 * Number of entries in the cache
73 */
74static atomic_t cache_count;
75
76static struct hlist_head cache_htable[CACHE_HTABLE_SIZE];
77static DECLARE_RWSEM(htable_rw_lock);
78
79static LIST_HEAD(mount_group_list);
80static DEFINE_MUTEX(mount_group_list_lock);
81
82static void refresh_cache_worker(struct work_struct *work);
83
84static DECLARE_DELAYED_WORK(refresh_task, refresh_cache_worker);
85
86static void __mount_group_release(struct mount_group *mg)
87{
88 int i;
89
90 for (i = 0; i < mg->num_sessions; i++)
91 cifs_put_smb_ses(mg->sessions[i]);
92 kfree(mg);
93}
94
95static void mount_group_release(struct kref *kref)
96{
97 struct mount_group *mg = container_of(kref, struct mount_group, refcount);
98
99 mutex_lock(&mount_group_list_lock);
100 list_del(&mg->list);
101 mutex_unlock(&mount_group_list_lock);
102 __mount_group_release(mg);
103}
104
105static struct mount_group *find_mount_group_locked(const uuid_t *id)
106{
107 struct mount_group *mg;
108
109 list_for_each_entry(mg, &mount_group_list, list) {
110 if (uuid_equal(&mg->id, id))
111 return mg;
112 }
113 return ERR_PTR(-ENOENT);
114}
115
116static struct mount_group *__get_mount_group_locked(const uuid_t *id)
117{
118 struct mount_group *mg;
119
120 mg = find_mount_group_locked(id);
121 if (!IS_ERR(mg))
122 return mg;
123
124 mg = kmalloc(sizeof(*mg), GFP_KERNEL);
125 if (!mg)
126 return ERR_PTR(-ENOMEM);
127 kref_init(&mg->refcount);
128 uuid_copy(&mg->id, id);
129 mg->num_sessions = 0;
130 spin_lock_init(&mg->lock);
131 list_add(&mg->list, &mount_group_list);
132 return mg;
133}
134
135static struct mount_group *get_mount_group(const uuid_t *id)
136{
137 struct mount_group *mg;
138
139 mutex_lock(&mount_group_list_lock);
140 mg = __get_mount_group_locked(id);
141 if (!IS_ERR(mg))
142 kref_get(&mg->refcount);
143 mutex_unlock(&mount_group_list_lock);
144
145 return mg;
146}
147
148static void free_mount_group_list(void)
149{
150 struct mount_group *mg, *tmp_mg;
151
152 list_for_each_entry_safe(mg, tmp_mg, &mount_group_list, list) {
153 list_del_init(&mg->list);
154 __mount_group_release(mg);
155 }
156}
157
158/**
159 * dfs_cache_canonical_path - get a canonical DFS path
160 *
161 * @path: DFS path
162 * @cp: codepage
163 * @remap: mapping type
164 *
165 * Return canonical path if success, otherwise error.
166 */
167char *dfs_cache_canonical_path(const char *path, const struct nls_table *cp, int remap)
168{
169 char *tmp;
170 int plen = 0;
171 char *npath;
172
173 if (!path || strlen(path) < 3 || (*path != '\\' && *path != '/'))
174 return ERR_PTR(-EINVAL);
175
176 if (unlikely(strcmp(cp->charset, cache_cp->charset))) {
177 tmp = (char *)cifs_strndup_to_utf16(path, strlen(path), &plen, cp, remap);
178 if (!tmp) {
179 cifs_dbg(VFS, "%s: failed to convert path to utf16\n", __func__);
180 return ERR_PTR(-EINVAL);
181 }
182
183 npath = cifs_strndup_from_utf16(tmp, plen, true, cache_cp);
184 kfree(tmp);
185
186 if (!npath) {
187 cifs_dbg(VFS, "%s: failed to convert path from utf16\n", __func__);
188 return ERR_PTR(-EINVAL);
189 }
190 } else {
191 npath = kstrdup(path, GFP_KERNEL);
192 if (!npath)
193 return ERR_PTR(-ENOMEM);
194 }
195 convert_delimiter(npath, '\\');
196 return npath;
197}
198
199static inline bool cache_entry_expired(const struct cache_entry *ce)
200{
201 struct timespec64 ts;
202
203 ktime_get_coarse_real_ts64(&ts);
204 return timespec64_compare(&ts, &ce->etime) >= 0;
205}
206
207static inline void free_tgts(struct cache_entry *ce)
208{
209 struct cache_dfs_tgt *t, *n;
210
211 list_for_each_entry_safe(t, n, &ce->tlist, list) {
212 list_del(&t->list);
213 kfree(t->name);
214 kfree(t);
215 }
216}
217
218static inline void flush_cache_ent(struct cache_entry *ce)
219{
220 hlist_del_init(&ce->hlist);
221 kfree(ce->path);
222 free_tgts(ce);
223 atomic_dec(&cache_count);
224 kmem_cache_free(cache_slab, ce);
225}
226
227static void flush_cache_ents(void)
228{
229 int i;
230
231 for (i = 0; i < CACHE_HTABLE_SIZE; i++) {
232 struct hlist_head *l = &cache_htable[i];
233 struct hlist_node *n;
234 struct cache_entry *ce;
235
236 hlist_for_each_entry_safe(ce, n, l, hlist) {
237 if (!hlist_unhashed(&ce->hlist))
238 flush_cache_ent(ce);
239 }
240 }
241}
242
243/*
244 * dfs cache /proc file
245 */
246static int dfscache_proc_show(struct seq_file *m, void *v)
247{
248 int i;
249 struct cache_entry *ce;
250 struct cache_dfs_tgt *t;
251
252 seq_puts(m, "DFS cache\n---------\n");
253
254 down_read(&htable_rw_lock);
255 for (i = 0; i < CACHE_HTABLE_SIZE; i++) {
256 struct hlist_head *l = &cache_htable[i];
257
258 hlist_for_each_entry(ce, l, hlist) {
259 if (hlist_unhashed(&ce->hlist))
260 continue;
261
262 seq_printf(m,
263 "cache entry: path=%s,type=%s,ttl=%d,etime=%ld,hdr_flags=0x%x,ref_flags=0x%x,interlink=%s,path_consumed=%d,expired=%s\n",
264 ce->path, ce->srvtype == DFS_TYPE_ROOT ? "root" : "link",
265 ce->ttl, ce->etime.tv_nsec, ce->hdr_flags, ce->ref_flags,
266 IS_DFS_INTERLINK(ce->hdr_flags) ? "yes" : "no",
267 ce->path_consumed, cache_entry_expired(ce) ? "yes" : "no");
268
269 list_for_each_entry(t, &ce->tlist, list) {
270 seq_printf(m, " %s%s\n",
271 t->name,
272 READ_ONCE(ce->tgthint) == t ? " (target hint)" : "");
273 }
274 }
275 }
276 up_read(&htable_rw_lock);
277
278 return 0;
279}
280
281static ssize_t dfscache_proc_write(struct file *file, const char __user *buffer,
282 size_t count, loff_t *ppos)
283{
284 char c;
285 int rc;
286
287 rc = get_user(c, buffer);
288 if (rc)
289 return rc;
290
291 if (c != '0')
292 return -EINVAL;
293
294 cifs_dbg(FYI, "clearing dfs cache\n");
295
296 down_write(&htable_rw_lock);
297 flush_cache_ents();
298 up_write(&htable_rw_lock);
299
300 return count;
301}
302
303static int dfscache_proc_open(struct inode *inode, struct file *file)
304{
305 return single_open(file, dfscache_proc_show, NULL);
306}
307
308const struct proc_ops dfscache_proc_ops = {
309 .proc_open = dfscache_proc_open,
310 .proc_read = seq_read,
311 .proc_lseek = seq_lseek,
312 .proc_release = single_release,
313 .proc_write = dfscache_proc_write,
314};
315
316#ifdef CONFIG_CIFS_DEBUG2
317static inline void dump_tgts(const struct cache_entry *ce)
318{
319 struct cache_dfs_tgt *t;
320
321 cifs_dbg(FYI, "target list:\n");
322 list_for_each_entry(t, &ce->tlist, list) {
323 cifs_dbg(FYI, " %s%s\n", t->name,
324 READ_ONCE(ce->tgthint) == t ? " (target hint)" : "");
325 }
326}
327
328static inline void dump_ce(const struct cache_entry *ce)
329{
330 cifs_dbg(FYI, "cache entry: path=%s,type=%s,ttl=%d,etime=%ld,hdr_flags=0x%x,ref_flags=0x%x,interlink=%s,path_consumed=%d,expired=%s\n",
331 ce->path,
332 ce->srvtype == DFS_TYPE_ROOT ? "root" : "link", ce->ttl,
333 ce->etime.tv_nsec,
334 ce->hdr_flags, ce->ref_flags,
335 IS_DFS_INTERLINK(ce->hdr_flags) ? "yes" : "no",
336 ce->path_consumed,
337 cache_entry_expired(ce) ? "yes" : "no");
338 dump_tgts(ce);
339}
340
341static inline void dump_refs(const struct dfs_info3_param *refs, int numrefs)
342{
343 int i;
344
345 cifs_dbg(FYI, "DFS referrals returned by the server:\n");
346 for (i = 0; i < numrefs; i++) {
347 const struct dfs_info3_param *ref = &refs[i];
348
349 cifs_dbg(FYI,
350 "\n"
351 "flags: 0x%x\n"
352 "path_consumed: %d\n"
353 "server_type: 0x%x\n"
354 "ref_flag: 0x%x\n"
355 "path_name: %s\n"
356 "node_name: %s\n"
357 "ttl: %d (%dm)\n",
358 ref->flags, ref->path_consumed, ref->server_type,
359 ref->ref_flag, ref->path_name, ref->node_name,
360 ref->ttl, ref->ttl / 60);
361 }
362}
363#else
364#define dump_tgts(e)
365#define dump_ce(e)
366#define dump_refs(r, n)
367#endif
368
369/**
370 * dfs_cache_init - Initialize DFS referral cache.
371 *
372 * Return zero if initialized successfully, otherwise non-zero.
373 */
374int dfs_cache_init(void)
375{
376 int rc;
377 int i;
378
379 dfscache_wq = alloc_workqueue("cifs-dfscache", WQ_FREEZABLE | WQ_UNBOUND, 1);
380 if (!dfscache_wq)
381 return -ENOMEM;
382
383 cache_slab = kmem_cache_create("cifs_dfs_cache",
384 sizeof(struct cache_entry), 0,
385 SLAB_HWCACHE_ALIGN, NULL);
386 if (!cache_slab) {
387 rc = -ENOMEM;
388 goto out_destroy_wq;
389 }
390
391 for (i = 0; i < CACHE_HTABLE_SIZE; i++)
392 INIT_HLIST_HEAD(&cache_htable[i]);
393
394 atomic_set(&cache_count, 0);
395 cache_cp = load_nls("utf8");
396 if (!cache_cp)
397 cache_cp = load_nls_default();
398
399 cifs_dbg(FYI, "%s: initialized DFS referral cache\n", __func__);
400 return 0;
401
402out_destroy_wq:
403 destroy_workqueue(dfscache_wq);
404 return rc;
405}
406
407static int cache_entry_hash(const void *data, int size, unsigned int *hash)
408{
409 int i, clen;
410 const unsigned char *s = data;
411 wchar_t c;
412 unsigned int h = 0;
413
414 for (i = 0; i < size; i += clen) {
415 clen = cache_cp->char2uni(&s[i], size - i, &c);
416 if (unlikely(clen < 0)) {
417 cifs_dbg(VFS, "%s: can't convert char\n", __func__);
418 return clen;
419 }
420 c = cifs_toupper(c);
421 h = jhash(&c, sizeof(c), h);
422 }
423 *hash = h % CACHE_HTABLE_SIZE;
424 return 0;
425}
426
427/* Return target hint of a DFS cache entry */
428static inline char *get_tgt_name(const struct cache_entry *ce)
429{
430 struct cache_dfs_tgt *t = READ_ONCE(ce->tgthint);
431
432 return t ? t->name : ERR_PTR(-ENOENT);
433}
434
435/* Return expire time out of a new entry's TTL */
436static inline struct timespec64 get_expire_time(int ttl)
437{
438 struct timespec64 ts = {
439 .tv_sec = ttl,
440 .tv_nsec = 0,
441 };
442 struct timespec64 now;
443
444 ktime_get_coarse_real_ts64(&now);
445 return timespec64_add(now, ts);
446}
447
448/* Allocate a new DFS target */
449static struct cache_dfs_tgt *alloc_target(const char *name, int path_consumed)
450{
451 struct cache_dfs_tgt *t;
452
453 t = kmalloc(sizeof(*t), GFP_ATOMIC);
454 if (!t)
455 return ERR_PTR(-ENOMEM);
456 t->name = kstrdup(name, GFP_ATOMIC);
457 if (!t->name) {
458 kfree(t);
459 return ERR_PTR(-ENOMEM);
460 }
461 t->path_consumed = path_consumed;
462 INIT_LIST_HEAD(&t->list);
463 return t;
464}
465
466/*
467 * Copy DFS referral information to a cache entry and conditionally update
468 * target hint.
469 */
470static int copy_ref_data(const struct dfs_info3_param *refs, int numrefs,
471 struct cache_entry *ce, const char *tgthint)
472{
473 struct cache_dfs_tgt *target;
474 int i;
475
476 ce->ttl = max_t(int, refs[0].ttl, CACHE_MIN_TTL);
477 ce->etime = get_expire_time(ce->ttl);
478 ce->srvtype = refs[0].server_type;
479 ce->hdr_flags = refs[0].flags;
480 ce->ref_flags = refs[0].ref_flag;
481 ce->path_consumed = refs[0].path_consumed;
482
483 for (i = 0; i < numrefs; i++) {
484 struct cache_dfs_tgt *t;
485
486 t = alloc_target(refs[i].node_name, refs[i].path_consumed);
487 if (IS_ERR(t)) {
488 free_tgts(ce);
489 return PTR_ERR(t);
490 }
491 if (tgthint && !strcasecmp(t->name, tgthint)) {
492 list_add(&t->list, &ce->tlist);
493 tgthint = NULL;
494 } else {
495 list_add_tail(&t->list, &ce->tlist);
496 }
497 ce->numtgts++;
498 }
499
500 target = list_first_entry_or_null(&ce->tlist, struct cache_dfs_tgt,
501 list);
502 WRITE_ONCE(ce->tgthint, target);
503
504 return 0;
505}
506
507/* Allocate a new cache entry */
508static struct cache_entry *alloc_cache_entry(struct dfs_info3_param *refs, int numrefs)
509{
510 struct cache_entry *ce;
511 int rc;
512
513 ce = kmem_cache_zalloc(cache_slab, GFP_KERNEL);
514 if (!ce)
515 return ERR_PTR(-ENOMEM);
516
517 ce->path = refs[0].path_name;
518 refs[0].path_name = NULL;
519
520 INIT_HLIST_NODE(&ce->hlist);
521 INIT_LIST_HEAD(&ce->tlist);
522
523 rc = copy_ref_data(refs, numrefs, ce, NULL);
524 if (rc) {
525 kfree(ce->path);
526 kmem_cache_free(cache_slab, ce);
527 ce = ERR_PTR(rc);
528 }
529 return ce;
530}
531
532static void remove_oldest_entry_locked(void)
533{
534 int i;
535 struct cache_entry *ce;
536 struct cache_entry *to_del = NULL;
537
538 WARN_ON(!rwsem_is_locked(&htable_rw_lock));
539
540 for (i = 0; i < CACHE_HTABLE_SIZE; i++) {
541 struct hlist_head *l = &cache_htable[i];
542
543 hlist_for_each_entry(ce, l, hlist) {
544 if (hlist_unhashed(&ce->hlist))
545 continue;
546 if (!to_del || timespec64_compare(&ce->etime,
547 &to_del->etime) < 0)
548 to_del = ce;
549 }
550 }
551
552 if (!to_del) {
553 cifs_dbg(FYI, "%s: no entry to remove\n", __func__);
554 return;
555 }
556
557 cifs_dbg(FYI, "%s: removing entry\n", __func__);
558 dump_ce(to_del);
559 flush_cache_ent(to_del);
560}
561
562/* Add a new DFS cache entry */
563static struct cache_entry *add_cache_entry_locked(struct dfs_info3_param *refs,
564 int numrefs)
565{
566 int rc;
567 struct cache_entry *ce;
568 unsigned int hash;
569
570 WARN_ON(!rwsem_is_locked(&htable_rw_lock));
571
572 if (atomic_read(&cache_count) >= CACHE_MAX_ENTRIES) {
573 cifs_dbg(FYI, "%s: reached max cache size (%d)\n", __func__, CACHE_MAX_ENTRIES);
574 remove_oldest_entry_locked();
575 }
576
577 rc = cache_entry_hash(refs[0].path_name, strlen(refs[0].path_name), &hash);
578 if (rc)
579 return ERR_PTR(rc);
580
581 ce = alloc_cache_entry(refs, numrefs);
582 if (IS_ERR(ce))
583 return ce;
584
585 spin_lock(&cache_ttl_lock);
586 if (!cache_ttl) {
587 cache_ttl = ce->ttl;
588 queue_delayed_work(dfscache_wq, &refresh_task, cache_ttl * HZ);
589 } else {
590 cache_ttl = min_t(int, cache_ttl, ce->ttl);
591 mod_delayed_work(dfscache_wq, &refresh_task, cache_ttl * HZ);
592 }
593 spin_unlock(&cache_ttl_lock);
594
595 hlist_add_head(&ce->hlist, &cache_htable[hash]);
596 dump_ce(ce);
597
598 atomic_inc(&cache_count);
599
600 return ce;
601}
602
603/* Check if two DFS paths are equal. @s1 and @s2 are expected to be in @cache_cp's charset */
604static bool dfs_path_equal(const char *s1, int len1, const char *s2, int len2)
605{
606 int i, l1, l2;
607 wchar_t c1, c2;
608
609 if (len1 != len2)
610 return false;
611
612 for (i = 0; i < len1; i += l1) {
613 l1 = cache_cp->char2uni(&s1[i], len1 - i, &c1);
614 l2 = cache_cp->char2uni(&s2[i], len2 - i, &c2);
615 if (unlikely(l1 < 0 && l2 < 0)) {
616 if (s1[i] != s2[i])
617 return false;
618 l1 = 1;
619 continue;
620 }
621 if (l1 != l2)
622 return false;
623 if (cifs_toupper(c1) != cifs_toupper(c2))
624 return false;
625 }
626 return true;
627}
628
629static struct cache_entry *__lookup_cache_entry(const char *path, unsigned int hash, int len)
630{
631 struct cache_entry *ce;
632
633 hlist_for_each_entry(ce, &cache_htable[hash], hlist) {
634 if (dfs_path_equal(ce->path, strlen(ce->path), path, len)) {
635 dump_ce(ce);
636 return ce;
637 }
638 }
639 return ERR_PTR(-ENOENT);
640}
641
642/*
643 * Find a DFS cache entry in hash table and optionally check prefix path against normalized @path.
644 *
645 * Use whole path components in the match. Must be called with htable_rw_lock held.
646 *
647 * Return cached entry if successful.
648 * Return ERR_PTR(-ENOENT) if the entry is not found.
649 * Return error ptr otherwise.
650 */
651static struct cache_entry *lookup_cache_entry(const char *path)
652{
653 struct cache_entry *ce;
654 int cnt = 0;
655 const char *s = path, *e;
656 char sep = *s;
657 unsigned int hash;
658 int rc;
659
660 while ((s = strchr(s, sep)) && ++cnt < 3)
661 s++;
662
663 if (cnt < 3) {
664 rc = cache_entry_hash(path, strlen(path), &hash);
665 if (rc)
666 return ERR_PTR(rc);
667 return __lookup_cache_entry(path, hash, strlen(path));
668 }
669 /*
670 * Handle paths that have more than two path components and are a complete prefix of the DFS
671 * referral request path (@path).
672 *
673 * See MS-DFSC 3.2.5.5 "Receiving a Root Referral Request or Link Referral Request".
674 */
675 e = path + strlen(path) - 1;
676 while (e > s) {
677 int len;
678
679 /* skip separators */
680 while (e > s && *e == sep)
681 e--;
682 if (e == s)
683 break;
684
685 len = e + 1 - path;
686 rc = cache_entry_hash(path, len, &hash);
687 if (rc)
688 return ERR_PTR(rc);
689 ce = __lookup_cache_entry(path, hash, len);
690 if (!IS_ERR(ce))
691 return ce;
692
693 /* backward until separator */
694 while (e > s && *e != sep)
695 e--;
696 }
697 return ERR_PTR(-ENOENT);
698}
699
700/**
701 * dfs_cache_destroy - destroy DFS referral cache
702 */
703void dfs_cache_destroy(void)
704{
705 cancel_delayed_work_sync(&refresh_task);
706 unload_nls(cache_cp);
707 free_mount_group_list();
708 flush_cache_ents();
709 kmem_cache_destroy(cache_slab);
710 destroy_workqueue(dfscache_wq);
711
712 cifs_dbg(FYI, "%s: destroyed DFS referral cache\n", __func__);
713}
714
715/* Update a cache entry with the new referral in @refs */
716static int update_cache_entry_locked(struct cache_entry *ce, const struct dfs_info3_param *refs,
717 int numrefs)
718{
719 struct cache_dfs_tgt *target;
720 char *th = NULL;
721 int rc;
722
723 WARN_ON(!rwsem_is_locked(&htable_rw_lock));
724
725 target = READ_ONCE(ce->tgthint);
726 if (target) {
727 th = kstrdup(target->name, GFP_ATOMIC);
728 if (!th)
729 return -ENOMEM;
730 }
731
732 free_tgts(ce);
733 ce->numtgts = 0;
734
735 rc = copy_ref_data(refs, numrefs, ce, th);
736
737 kfree(th);
738
739 return rc;
740}
741
742static int get_dfs_referral(const unsigned int xid, struct cifs_ses *ses, const char *path,
743 struct dfs_info3_param **refs, int *numrefs)
744{
745 int rc;
746 int i;
747
748 *refs = NULL;
749 *numrefs = 0;
750
751 if (!ses || !ses->server || !ses->server->ops->get_dfs_refer)
752 return -EOPNOTSUPP;
753 if (unlikely(!cache_cp))
754 return -EINVAL;
755
756 cifs_dbg(FYI, "%s: ipc=%s referral=%s\n", __func__, ses->tcon_ipc->tree_name, path);
757 rc = ses->server->ops->get_dfs_refer(xid, ses, path, refs, numrefs, cache_cp,
758 NO_MAP_UNI_RSVD);
759 if (!rc) {
760 struct dfs_info3_param *ref = *refs;
761
762 for (i = 0; i < *numrefs; i++)
763 convert_delimiter(ref[i].path_name, '\\');
764 }
765 return rc;
766}
767
768/*
769 * Find, create or update a DFS cache entry.
770 *
771 * If the entry wasn't found, it will create a new one. Or if it was found but
772 * expired, then it will update the entry accordingly.
773 *
774 * For interlinks, cifs_mount() and expand_dfs_referral() are supposed to
775 * handle them properly.
776 *
777 * On success, return entry with acquired lock for reading, otherwise error ptr.
778 */
779static struct cache_entry *cache_refresh_path(const unsigned int xid,
780 struct cifs_ses *ses,
781 const char *path,
782 bool force_refresh)
783{
784 struct dfs_info3_param *refs = NULL;
785 struct cache_entry *ce;
786 int numrefs = 0;
787 int rc;
788
789 cifs_dbg(FYI, "%s: search path: %s\n", __func__, path);
790
791 down_read(&htable_rw_lock);
792
793 ce = lookup_cache_entry(path);
794 if (!IS_ERR(ce)) {
795 if (!force_refresh && !cache_entry_expired(ce))
796 return ce;
797 } else if (PTR_ERR(ce) != -ENOENT) {
798 up_read(&htable_rw_lock);
799 return ce;
800 }
801
802 /*
803 * Unlock shared access as we don't want to hold any locks while getting
804 * a new referral. The @ses used for performing the I/O could be
805 * reconnecting and it acquires @htable_rw_lock to look up the dfs cache
806 * in order to failover -- if necessary.
807 */
808 up_read(&htable_rw_lock);
809
810 /*
811 * Either the entry was not found, or it is expired, or it is a forced
812 * refresh.
813 * Request a new DFS referral in order to create or update a cache entry.
814 */
815 rc = get_dfs_referral(xid, ses, path, &refs, &numrefs);
816 if (rc) {
817 ce = ERR_PTR(rc);
818 goto out;
819 }
820
821 dump_refs(refs, numrefs);
822
823 down_write(&htable_rw_lock);
824 /* Re-check as another task might have it added or refreshed already */
825 ce = lookup_cache_entry(path);
826 if (!IS_ERR(ce)) {
827 if (force_refresh || cache_entry_expired(ce)) {
828 rc = update_cache_entry_locked(ce, refs, numrefs);
829 if (rc)
830 ce = ERR_PTR(rc);
831 }
832 } else if (PTR_ERR(ce) == -ENOENT) {
833 ce = add_cache_entry_locked(refs, numrefs);
834 }
835
836 if (IS_ERR(ce)) {
837 up_write(&htable_rw_lock);
838 goto out;
839 }
840
841 downgrade_write(&htable_rw_lock);
842out:
843 free_dfs_info_array(refs, numrefs);
844 return ce;
845}
846
847/*
848 * Set up a DFS referral from a given cache entry.
849 *
850 * Must be called with htable_rw_lock held.
851 */
852static int setup_referral(const char *path, struct cache_entry *ce,
853 struct dfs_info3_param *ref, const char *target)
854{
855 int rc;
856
857 cifs_dbg(FYI, "%s: set up new ref\n", __func__);
858
859 memset(ref, 0, sizeof(*ref));
860
861 ref->path_name = kstrdup(path, GFP_ATOMIC);
862 if (!ref->path_name)
863 return -ENOMEM;
864
865 ref->node_name = kstrdup(target, GFP_ATOMIC);
866 if (!ref->node_name) {
867 rc = -ENOMEM;
868 goto err_free_path;
869 }
870
871 ref->path_consumed = ce->path_consumed;
872 ref->ttl = ce->ttl;
873 ref->server_type = ce->srvtype;
874 ref->ref_flag = ce->ref_flags;
875 ref->flags = ce->hdr_flags;
876
877 return 0;
878
879err_free_path:
880 kfree(ref->path_name);
881 ref->path_name = NULL;
882 return rc;
883}
884
885/* Return target list of a DFS cache entry */
886static int get_targets(struct cache_entry *ce, struct dfs_cache_tgt_list *tl)
887{
888 int rc;
889 struct list_head *head = &tl->tl_list;
890 struct cache_dfs_tgt *t;
891 struct dfs_cache_tgt_iterator *it, *nit;
892
893 memset(tl, 0, sizeof(*tl));
894 INIT_LIST_HEAD(head);
895
896 list_for_each_entry(t, &ce->tlist, list) {
897 it = kzalloc(sizeof(*it), GFP_ATOMIC);
898 if (!it) {
899 rc = -ENOMEM;
900 goto err_free_it;
901 }
902
903 it->it_name = kstrdup(t->name, GFP_ATOMIC);
904 if (!it->it_name) {
905 kfree(it);
906 rc = -ENOMEM;
907 goto err_free_it;
908 }
909 it->it_path_consumed = t->path_consumed;
910
911 if (READ_ONCE(ce->tgthint) == t)
912 list_add(&it->it_list, head);
913 else
914 list_add_tail(&it->it_list, head);
915 }
916
917 tl->tl_numtgts = ce->numtgts;
918
919 return 0;
920
921err_free_it:
922 list_for_each_entry_safe(it, nit, head, it_list) {
923 list_del(&it->it_list);
924 kfree(it->it_name);
925 kfree(it);
926 }
927 return rc;
928}
929
930/**
931 * dfs_cache_find - find a DFS cache entry
932 *
933 * If it doesn't find the cache entry, then it will get a DFS referral
934 * for @path and create a new entry.
935 *
936 * In case the cache entry exists but expired, it will get a DFS referral
937 * for @path and then update the respective cache entry.
938 *
939 * These parameters are passed down to the get_dfs_refer() call if it
940 * needs to be issued:
941 * @xid: syscall xid
942 * @ses: smb session to issue the request on
943 * @cp: codepage
944 * @remap: path character remapping type
945 * @path: path to lookup in DFS referral cache.
946 *
947 * @ref: when non-NULL, store single DFS referral result in it.
948 * @tgt_list: when non-NULL, store complete DFS target list in it.
949 *
950 * Return zero if the target was found, otherwise non-zero.
951 */
952int dfs_cache_find(const unsigned int xid, struct cifs_ses *ses, const struct nls_table *cp,
953 int remap, const char *path, struct dfs_info3_param *ref,
954 struct dfs_cache_tgt_list *tgt_list)
955{
956 int rc;
957 const char *npath;
958 struct cache_entry *ce;
959
960 npath = dfs_cache_canonical_path(path, cp, remap);
961 if (IS_ERR(npath))
962 return PTR_ERR(npath);
963
964 ce = cache_refresh_path(xid, ses, npath, false);
965 if (IS_ERR(ce)) {
966 rc = PTR_ERR(ce);
967 goto out_free_path;
968 }
969
970 if (ref)
971 rc = setup_referral(path, ce, ref, get_tgt_name(ce));
972 else
973 rc = 0;
974 if (!rc && tgt_list)
975 rc = get_targets(ce, tgt_list);
976
977 up_read(&htable_rw_lock);
978
979out_free_path:
980 kfree(npath);
981 return rc;
982}
983
984/**
985 * dfs_cache_noreq_find - find a DFS cache entry without sending any requests to
986 * the currently connected server.
987 *
988 * NOTE: This function will neither update a cache entry in case it was
989 * expired, nor create a new cache entry if @path hasn't been found. It heavily
990 * relies on an existing cache entry.
991 *
992 * @path: canonical DFS path to lookup in the DFS referral cache.
993 * @ref: when non-NULL, store single DFS referral result in it.
994 * @tgt_list: when non-NULL, store complete DFS target list in it.
995 *
996 * Return 0 if successful.
997 * Return -ENOENT if the entry was not found.
998 * Return non-zero for other errors.
999 */
1000int dfs_cache_noreq_find(const char *path, struct dfs_info3_param *ref,
1001 struct dfs_cache_tgt_list *tgt_list)
1002{
1003 int rc;
1004 struct cache_entry *ce;
1005
1006 cifs_dbg(FYI, "%s: path: %s\n", __func__, path);
1007
1008 down_read(&htable_rw_lock);
1009
1010 ce = lookup_cache_entry(path);
1011 if (IS_ERR(ce)) {
1012 rc = PTR_ERR(ce);
1013 goto out_unlock;
1014 }
1015
1016 if (ref)
1017 rc = setup_referral(path, ce, ref, get_tgt_name(ce));
1018 else
1019 rc = 0;
1020 if (!rc && tgt_list)
1021 rc = get_targets(ce, tgt_list);
1022
1023out_unlock:
1024 up_read(&htable_rw_lock);
1025 return rc;
1026}
1027
1028/**
1029 * dfs_cache_noreq_update_tgthint - update target hint of a DFS cache entry
1030 * without sending any requests to the currently connected server.
1031 *
1032 * NOTE: This function will neither update a cache entry in case it was
1033 * expired, nor create a new cache entry if @path hasn't been found. It heavily
1034 * relies on an existing cache entry.
1035 *
1036 * @path: canonical DFS path to lookup in DFS referral cache.
1037 * @it: target iterator which contains the target hint to update the cache
1038 * entry with.
1039 *
1040 * Return zero if the target hint was updated successfully, otherwise non-zero.
1041 */
1042void dfs_cache_noreq_update_tgthint(const char *path, const struct dfs_cache_tgt_iterator *it)
1043{
1044 struct cache_dfs_tgt *t;
1045 struct cache_entry *ce;
1046
1047 if (!path || !it)
1048 return;
1049
1050 cifs_dbg(FYI, "%s: path: %s\n", __func__, path);
1051
1052 down_read(&htable_rw_lock);
1053
1054 ce = lookup_cache_entry(path);
1055 if (IS_ERR(ce))
1056 goto out_unlock;
1057
1058 t = READ_ONCE(ce->tgthint);
1059
1060 if (unlikely(!strcasecmp(it->it_name, t->name)))
1061 goto out_unlock;
1062
1063 list_for_each_entry(t, &ce->tlist, list) {
1064 if (!strcasecmp(t->name, it->it_name)) {
1065 WRITE_ONCE(ce->tgthint, t);
1066 cifs_dbg(FYI, "%s: new target hint: %s\n", __func__,
1067 it->it_name);
1068 break;
1069 }
1070 }
1071
1072out_unlock:
1073 up_read(&htable_rw_lock);
1074}
1075
1076/**
1077 * dfs_cache_get_tgt_referral - returns a DFS referral (@ref) from a given
1078 * target iterator (@it).
1079 *
1080 * @path: canonical DFS path to lookup in DFS referral cache.
1081 * @it: DFS target iterator.
1082 * @ref: DFS referral pointer to set up the gathered information.
1083 *
1084 * Return zero if the DFS referral was set up correctly, otherwise non-zero.
1085 */
1086int dfs_cache_get_tgt_referral(const char *path, const struct dfs_cache_tgt_iterator *it,
1087 struct dfs_info3_param *ref)
1088{
1089 int rc;
1090 struct cache_entry *ce;
1091
1092 if (!it || !ref)
1093 return -EINVAL;
1094
1095 cifs_dbg(FYI, "%s: path: %s\n", __func__, path);
1096
1097 down_read(&htable_rw_lock);
1098
1099 ce = lookup_cache_entry(path);
1100 if (IS_ERR(ce)) {
1101 rc = PTR_ERR(ce);
1102 goto out_unlock;
1103 }
1104
1105 cifs_dbg(FYI, "%s: target name: %s\n", __func__, it->it_name);
1106
1107 rc = setup_referral(path, ce, ref, it->it_name);
1108
1109out_unlock:
1110 up_read(&htable_rw_lock);
1111 return rc;
1112}
1113
1114/**
1115 * dfs_cache_add_refsrv_session - add SMB session of referral server
1116 *
1117 * @mount_id: mount group uuid to lookup.
1118 * @ses: reference counted SMB session of referral server.
1119 */
1120void dfs_cache_add_refsrv_session(const uuid_t *mount_id, struct cifs_ses *ses)
1121{
1122 struct mount_group *mg;
1123
1124 if (WARN_ON_ONCE(!mount_id || uuid_is_null(mount_id) || !ses))
1125 return;
1126
1127 mg = get_mount_group(mount_id);
1128 if (WARN_ON_ONCE(IS_ERR(mg)))
1129 return;
1130
1131 spin_lock(&mg->lock);
1132 if (mg->num_sessions < ARRAY_SIZE(mg->sessions))
1133 mg->sessions[mg->num_sessions++] = ses;
1134 spin_unlock(&mg->lock);
1135 kref_put(&mg->refcount, mount_group_release);
1136}
1137
1138/**
1139 * dfs_cache_put_refsrv_sessions - put all referral server sessions
1140 *
1141 * Put all SMB sessions from the given mount group id.
1142 *
1143 * @mount_id: mount group uuid to lookup.
1144 */
1145void dfs_cache_put_refsrv_sessions(const uuid_t *mount_id)
1146{
1147 struct mount_group *mg;
1148
1149 if (!mount_id || uuid_is_null(mount_id))
1150 return;
1151
1152 mutex_lock(&mount_group_list_lock);
1153 mg = find_mount_group_locked(mount_id);
1154 if (IS_ERR(mg)) {
1155 mutex_unlock(&mount_group_list_lock);
1156 return;
1157 }
1158 mutex_unlock(&mount_group_list_lock);
1159 kref_put(&mg->refcount, mount_group_release);
1160}
1161
1162/* Extract share from DFS target and return a pointer to prefix path or NULL */
1163static const char *parse_target_share(const char *target, char **share)
1164{
1165 const char *s, *seps = "/\\";
1166 size_t len;
1167
1168 s = strpbrk(target + 1, seps);
1169 if (!s)
1170 return ERR_PTR(-EINVAL);
1171
1172 len = strcspn(s + 1, seps);
1173 if (!len)
1174 return ERR_PTR(-EINVAL);
1175 s += len;
1176
1177 len = s - target + 1;
1178 *share = kstrndup(target, len, GFP_KERNEL);
1179 if (!*share)
1180 return ERR_PTR(-ENOMEM);
1181
1182 s = target + len;
1183 return s + strspn(s, seps);
1184}
1185
1186/**
1187 * dfs_cache_get_tgt_share - parse a DFS target
1188 *
1189 * @path: DFS full path
1190 * @it: DFS target iterator.
1191 * @share: tree name.
1192 * @prefix: prefix path.
1193 *
1194 * Return zero if target was parsed correctly, otherwise non-zero.
1195 */
1196int dfs_cache_get_tgt_share(char *path, const struct dfs_cache_tgt_iterator *it, char **share,
1197 char **prefix)
1198{
1199 char sep;
1200 char *target_share;
1201 char *ppath = NULL;
1202 const char *target_ppath, *dfsref_ppath;
1203 size_t target_pplen, dfsref_pplen;
1204 size_t len, c;
1205
1206 if (!it || !path || !share || !prefix || strlen(path) < it->it_path_consumed)
1207 return -EINVAL;
1208
1209 sep = it->it_name[0];
1210 if (sep != '\\' && sep != '/')
1211 return -EINVAL;
1212
1213 target_ppath = parse_target_share(it->it_name, &target_share);
1214 if (IS_ERR(target_ppath))
1215 return PTR_ERR(target_ppath);
1216
1217 /* point to prefix in DFS referral path */
1218 dfsref_ppath = path + it->it_path_consumed;
1219 dfsref_ppath += strspn(dfsref_ppath, "/\\");
1220
1221 target_pplen = strlen(target_ppath);
1222 dfsref_pplen = strlen(dfsref_ppath);
1223
1224 /* merge prefix paths from DFS referral path and target node */
1225 if (target_pplen || dfsref_pplen) {
1226 len = target_pplen + dfsref_pplen + 2;
1227 ppath = kzalloc(len, GFP_KERNEL);
1228 if (!ppath) {
1229 kfree(target_share);
1230 return -ENOMEM;
1231 }
1232 c = strscpy(ppath, target_ppath, len);
1233 if (c && dfsref_pplen)
1234 ppath[c] = sep;
1235 strlcat(ppath, dfsref_ppath, len);
1236 }
1237 *share = target_share;
1238 *prefix = ppath;
1239 return 0;
1240}
1241
1242static bool target_share_equal(struct TCP_Server_Info *server, const char *s1, const char *s2)
1243{
1244 char unc[sizeof("\\\\") + SERVER_NAME_LENGTH] = {0};
1245 const char *host;
1246 size_t hostlen;
1247 struct sockaddr_storage ss;
1248 bool match;
1249 int rc;
1250
1251 if (strcasecmp(s1, s2))
1252 return false;
1253
1254 /*
1255 * Resolve share's hostname and check if server address matches. Otherwise just ignore it
1256 * as we could not have upcall to resolve hostname or failed to convert ip address.
1257 */
1258 extract_unc_hostname(s1, &host, &hostlen);
1259 scnprintf(unc, sizeof(unc), "\\\\%.*s", (int)hostlen, host);
1260
1261 rc = dns_resolve_server_name_to_ip(unc, (struct sockaddr *)&ss, NULL);
1262 if (rc < 0) {
1263 cifs_dbg(FYI, "%s: could not resolve %.*s. assuming server address matches.\n",
1264 __func__, (int)hostlen, host);
1265 return true;
1266 }
1267
1268 cifs_server_lock(server);
1269 match = cifs_match_ipaddr((struct sockaddr *)&server->dstaddr, (struct sockaddr *)&ss);
1270 cifs_server_unlock(server);
1271
1272 return match;
1273}
1274
1275/*
1276 * Mark dfs tcon for reconnecting when the currently connected tcon does not match any of the new
1277 * target shares in @refs.
1278 */
1279static void mark_for_reconnect_if_needed(struct TCP_Server_Info *server,
1280 struct dfs_cache_tgt_list *old_tl,
1281 struct dfs_cache_tgt_list *new_tl)
1282{
1283 struct dfs_cache_tgt_iterator *oit, *nit;
1284
1285 for (oit = dfs_cache_get_tgt_iterator(old_tl); oit;
1286 oit = dfs_cache_get_next_tgt(old_tl, oit)) {
1287 for (nit = dfs_cache_get_tgt_iterator(new_tl); nit;
1288 nit = dfs_cache_get_next_tgt(new_tl, nit)) {
1289 if (target_share_equal(server,
1290 dfs_cache_get_tgt_name(oit),
1291 dfs_cache_get_tgt_name(nit)))
1292 return;
1293 }
1294 }
1295
1296 cifs_dbg(FYI, "%s: no cached or matched targets. mark dfs share for reconnect.\n", __func__);
1297 cifs_signal_cifsd_for_reconnect(server, true);
1298}
1299
1300/* Refresh dfs referral of tcon and mark it for reconnect if needed */
1301static int __refresh_tcon(const char *path, struct cifs_tcon *tcon, bool force_refresh)
1302{
1303 struct dfs_cache_tgt_list old_tl = DFS_CACHE_TGT_LIST_INIT(old_tl);
1304 struct dfs_cache_tgt_list new_tl = DFS_CACHE_TGT_LIST_INIT(new_tl);
1305 struct cifs_ses *ses = CIFS_DFS_ROOT_SES(tcon->ses);
1306 struct cifs_tcon *ipc = ses->tcon_ipc;
1307 bool needs_refresh = false;
1308 struct cache_entry *ce;
1309 unsigned int xid;
1310 int rc = 0;
1311
1312 xid = get_xid();
1313
1314 down_read(&htable_rw_lock);
1315 ce = lookup_cache_entry(path);
1316 needs_refresh = force_refresh || IS_ERR(ce) || cache_entry_expired(ce);
1317 if (!IS_ERR(ce)) {
1318 rc = get_targets(ce, &old_tl);
1319 cifs_dbg(FYI, "%s: get_targets: %d\n", __func__, rc);
1320 }
1321 up_read(&htable_rw_lock);
1322
1323 if (!needs_refresh) {
1324 rc = 0;
1325 goto out;
1326 }
1327
1328 spin_lock(&ipc->tc_lock);
1329 if (ses->ses_status != SES_GOOD || ipc->status != TID_GOOD) {
1330 spin_unlock(&ipc->tc_lock);
1331 cifs_dbg(FYI, "%s: skip cache refresh due to disconnected ipc\n", __func__);
1332 goto out;
1333 }
1334 spin_unlock(&ipc->tc_lock);
1335
1336 ce = cache_refresh_path(xid, ses, path, true);
1337 if (!IS_ERR(ce)) {
1338 rc = get_targets(ce, &new_tl);
1339 up_read(&htable_rw_lock);
1340 cifs_dbg(FYI, "%s: get_targets: %d\n", __func__, rc);
1341 mark_for_reconnect_if_needed(tcon->ses->server, &old_tl, &new_tl);
1342 }
1343
1344out:
1345 free_xid(xid);
1346 dfs_cache_free_tgts(&old_tl);
1347 dfs_cache_free_tgts(&new_tl);
1348 return rc;
1349}
1350
1351static int refresh_tcon(struct cifs_tcon *tcon, bool force_refresh)
1352{
1353 struct TCP_Server_Info *server = tcon->ses->server;
1354
1355 mutex_lock(&server->refpath_lock);
1356 if (server->leaf_fullpath)
1357 __refresh_tcon(server->leaf_fullpath + 1, tcon, force_refresh);
1358 mutex_unlock(&server->refpath_lock);
1359 return 0;
1360}
1361
1362/**
1363 * dfs_cache_remount_fs - remount a DFS share
1364 *
1365 * Reconfigure dfs mount by forcing a new DFS referral and if the currently cached targets do not
1366 * match any of the new targets, mark it for reconnect.
1367 *
1368 * @cifs_sb: cifs superblock.
1369 *
1370 * Return zero if remounted, otherwise non-zero.
1371 */
1372int dfs_cache_remount_fs(struct cifs_sb_info *cifs_sb)
1373{
1374 struct cifs_tcon *tcon;
1375 struct TCP_Server_Info *server;
1376
1377 if (!cifs_sb || !cifs_sb->master_tlink)
1378 return -EINVAL;
1379
1380 tcon = cifs_sb_master_tcon(cifs_sb);
1381 server = tcon->ses->server;
1382
1383 if (!server->origin_fullpath) {
1384 cifs_dbg(FYI, "%s: not a dfs mount\n", __func__);
1385 return 0;
1386 }
1387
1388 if (uuid_is_null(&cifs_sb->dfs_mount_id)) {
1389 cifs_dbg(FYI, "%s: no dfs mount group id\n", __func__);
1390 return -EINVAL;
1391 }
1392 /*
1393 * After reconnecting to a different server, unique ids won't match anymore, so we disable
1394 * serverino. This prevents dentry revalidation to think the dentry are stale (ESTALE).
1395 */
1396 cifs_autodisable_serverino(cifs_sb);
1397 /*
1398 * Force the use of prefix path to support failover on DFS paths that resolve to targets
1399 * that have different prefix paths.
1400 */
1401 cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_USE_PREFIX_PATH;
1402
1403 return refresh_tcon(tcon, true);
1404}
1405
1406/*
1407 * Worker that will refresh DFS cache from all active mounts based on lowest TTL value
1408 * from a DFS referral.
1409 */
1410static void refresh_cache_worker(struct work_struct *work)
1411{
1412 struct TCP_Server_Info *server;
1413 struct cifs_tcon *tcon, *ntcon;
1414 struct list_head tcons;
1415 struct cifs_ses *ses;
1416
1417 INIT_LIST_HEAD(&tcons);
1418
1419 spin_lock(&cifs_tcp_ses_lock);
1420 list_for_each_entry(server, &cifs_tcp_ses_list, tcp_ses_list) {
1421 if (!server->leaf_fullpath)
1422 continue;
1423
1424 list_for_each_entry(ses, &server->smb_ses_list, smb_ses_list) {
1425 if (ses->tcon_ipc) {
1426 ses->ses_count++;
1427 list_add_tail(&ses->tcon_ipc->ulist, &tcons);
1428 }
1429 list_for_each_entry(tcon, &ses->tcon_list, tcon_list) {
1430 if (!tcon->ipc) {
1431 tcon->tc_count++;
1432 list_add_tail(&tcon->ulist, &tcons);
1433 }
1434 }
1435 }
1436 }
1437 spin_unlock(&cifs_tcp_ses_lock);
1438
1439 list_for_each_entry_safe(tcon, ntcon, &tcons, ulist) {
1440 struct TCP_Server_Info *server = tcon->ses->server;
1441
1442 list_del_init(&tcon->ulist);
1443
1444 mutex_lock(&server->refpath_lock);
1445 if (server->leaf_fullpath)
1446 __refresh_tcon(server->leaf_fullpath + 1, tcon, false);
1447 mutex_unlock(&server->refpath_lock);
1448
1449 if (tcon->ipc)
1450 cifs_put_smb_ses(tcon->ses);
1451 else
1452 cifs_put_tcon(tcon);
1453 }
1454
1455 spin_lock(&cache_ttl_lock);
1456 queue_delayed_work(dfscache_wq, &refresh_task, cache_ttl * HZ);
1457 spin_unlock(&cache_ttl_lock);
1458}