1 // SPDX-License-Identifier: GPL-2.0
3 * DFS referral cache routines
5 * Copyright (c) 2018-2019 Paulo Alcantara <palcantara@suse.de>
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>
16 #include "smb2proto.h"
17 #include "cifsproto.h"
18 #include "cifs_debug.h"
19 #include "cifs_unicode.h"
21 #include "fs_context.h"
23 #include "dfs_cache.h"
25 #define CACHE_HTABLE_SIZE 32
26 #define CACHE_MAX_ENTRIES 64
28 #define IS_INTERLINK_SET(v) ((v) & (DFSREF_REFERRAL_SERVER | \
29 DFSREF_STORAGE_SERVER))
31 struct cache_dfs_tgt {
34 struct list_head list;
38 struct hlist_node hlist;
40 int hdr_flags; /* RESP_GET_DFS_REFERRAL.ReferralHeaderFlags */
41 int ttl; /* DFS_REREFERRAL_V3.TimeToLive */
42 int srvtype; /* DFS_REREFERRAL_V3.ServerType */
43 int ref_flags; /* DFS_REREFERRAL_V3.ReferralEntryFlags */
44 struct timespec64 etime;
45 int path_consumed; /* RESP_GET_DFS_REFERRAL.PathConsumed */
47 struct list_head tlist;
48 struct cache_dfs_tgt *tgthint;
54 struct smb3_fs_context ctx;
56 struct list_head list;
57 struct list_head rlist;
61 static struct kmem_cache *cache_slab __read_mostly;
62 static struct workqueue_struct *dfscache_wq __read_mostly;
65 static DEFINE_SPINLOCK(cache_ttl_lock);
67 static struct nls_table *cache_nlsc;
70 * Number of entries in the cache
72 static atomic_t cache_count;
74 static struct hlist_head cache_htable[CACHE_HTABLE_SIZE];
75 static DECLARE_RWSEM(htable_rw_lock);
77 static LIST_HEAD(vol_list);
78 static DEFINE_SPINLOCK(vol_list_lock);
80 static void refresh_cache_worker(struct work_struct *work);
82 static DECLARE_DELAYED_WORK(refresh_task, refresh_cache_worker);
84 static int get_normalized_path(const char *path, char **npath)
86 if (!path || strlen(path) < 3 || (*path != '\\' && *path != '/'))
90 *npath = (char *)path;
92 *npath = kstrndup(path, strlen(path), GFP_KERNEL);
95 convert_delimiter(*npath, '\\');
100 static inline void free_normalized_path(const char *path, char *npath)
106 static inline bool cache_entry_expired(const struct cache_entry *ce)
108 struct timespec64 ts;
110 ktime_get_coarse_real_ts64(&ts);
111 return timespec64_compare(&ts, &ce->etime) >= 0;
114 static inline void free_tgts(struct cache_entry *ce)
116 struct cache_dfs_tgt *t, *n;
118 list_for_each_entry_safe(t, n, &ce->tlist, list) {
125 static inline void flush_cache_ent(struct cache_entry *ce)
127 hlist_del_init(&ce->hlist);
130 atomic_dec(&cache_count);
131 kmem_cache_free(cache_slab, ce);
134 static void flush_cache_ents(void)
138 for (i = 0; i < CACHE_HTABLE_SIZE; i++) {
139 struct hlist_head *l = &cache_htable[i];
140 struct hlist_node *n;
141 struct cache_entry *ce;
143 hlist_for_each_entry_safe(ce, n, l, hlist) {
144 if (!hlist_unhashed(&ce->hlist))
151 * dfs cache /proc file
153 static int dfscache_proc_show(struct seq_file *m, void *v)
156 struct cache_entry *ce;
157 struct cache_dfs_tgt *t;
159 seq_puts(m, "DFS cache\n---------\n");
161 down_read(&htable_rw_lock);
162 for (i = 0; i < CACHE_HTABLE_SIZE; i++) {
163 struct hlist_head *l = &cache_htable[i];
165 hlist_for_each_entry(ce, l, hlist) {
166 if (hlist_unhashed(&ce->hlist))
170 "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",
171 ce->path, ce->srvtype == DFS_TYPE_ROOT ? "root" : "link",
172 ce->ttl, ce->etime.tv_nsec, ce->ref_flags, ce->hdr_flags,
173 IS_INTERLINK_SET(ce->hdr_flags) ? "yes" : "no",
174 ce->path_consumed, cache_entry_expired(ce) ? "yes" : "no");
176 list_for_each_entry(t, &ce->tlist, list) {
177 seq_printf(m, " %s%s\n",
179 ce->tgthint == t ? " (target hint)" : "");
183 up_read(&htable_rw_lock);
188 static ssize_t dfscache_proc_write(struct file *file, const char __user *buffer,
189 size_t count, loff_t *ppos)
194 rc = get_user(c, buffer);
201 cifs_dbg(FYI, "clearing dfs cache\n");
203 down_write(&htable_rw_lock);
205 up_write(&htable_rw_lock);
210 static int dfscache_proc_open(struct inode *inode, struct file *file)
212 return single_open(file, dfscache_proc_show, NULL);
215 const struct proc_ops dfscache_proc_ops = {
216 .proc_open = dfscache_proc_open,
217 .proc_read = seq_read,
218 .proc_lseek = seq_lseek,
219 .proc_release = single_release,
220 .proc_write = dfscache_proc_write,
223 #ifdef CONFIG_CIFS_DEBUG2
224 static inline void dump_tgts(const struct cache_entry *ce)
226 struct cache_dfs_tgt *t;
228 cifs_dbg(FYI, "target list:\n");
229 list_for_each_entry(t, &ce->tlist, list) {
230 cifs_dbg(FYI, " %s%s\n", t->name,
231 ce->tgthint == t ? " (target hint)" : "");
235 static inline void dump_ce(const struct cache_entry *ce)
237 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",
239 ce->srvtype == DFS_TYPE_ROOT ? "root" : "link", ce->ttl,
241 ce->hdr_flags, ce->ref_flags,
242 IS_INTERLINK_SET(ce->hdr_flags) ? "yes" : "no",
244 cache_entry_expired(ce) ? "yes" : "no");
248 static inline void dump_refs(const struct dfs_info3_param *refs, int numrefs)
252 cifs_dbg(FYI, "DFS referrals returned by the server:\n");
253 for (i = 0; i < numrefs; i++) {
254 const struct dfs_info3_param *ref = &refs[i];
259 "path_consumed: %d\n"
260 "server_type: 0x%x\n"
265 ref->flags, ref->path_consumed, ref->server_type,
266 ref->ref_flag, ref->path_name, ref->node_name,
267 ref->ttl, ref->ttl / 60);
273 #define dump_refs(r, n)
277 * dfs_cache_init - Initialize DFS referral cache.
279 * Return zero if initialized successfully, otherwise non-zero.
281 int dfs_cache_init(void)
286 dfscache_wq = alloc_workqueue("cifs-dfscache",
287 WQ_FREEZABLE | WQ_MEM_RECLAIM, 1);
291 cache_slab = kmem_cache_create("cifs_dfs_cache",
292 sizeof(struct cache_entry), 0,
293 SLAB_HWCACHE_ALIGN, NULL);
299 for (i = 0; i < CACHE_HTABLE_SIZE; i++)
300 INIT_HLIST_HEAD(&cache_htable[i]);
302 atomic_set(&cache_count, 0);
303 cache_nlsc = load_nls_default();
305 cifs_dbg(FYI, "%s: initialized DFS referral cache\n", __func__);
309 destroy_workqueue(dfscache_wq);
313 static inline unsigned int cache_entry_hash(const void *data, int size)
317 h = jhash(data, size, 0);
318 return h & (CACHE_HTABLE_SIZE - 1);
321 /* Check whether second path component of @path is SYSVOL or NETLOGON */
322 static inline bool is_sysvol_or_netlogon(const char *path)
327 s = strchr(path + 1, sep) + 1;
328 return !strncasecmp(s, "sysvol", strlen("sysvol")) ||
329 !strncasecmp(s, "netlogon", strlen("netlogon"));
332 /* Return target hint of a DFS cache entry */
333 static inline char *get_tgt_name(const struct cache_entry *ce)
335 struct cache_dfs_tgt *t = ce->tgthint;
337 return t ? t->name : ERR_PTR(-ENOENT);
340 /* Return expire time out of a new entry's TTL */
341 static inline struct timespec64 get_expire_time(int ttl)
343 struct timespec64 ts = {
347 struct timespec64 now;
349 ktime_get_coarse_real_ts64(&now);
350 return timespec64_add(now, ts);
353 /* Allocate a new DFS target */
354 static struct cache_dfs_tgt *alloc_target(const char *name, int path_consumed)
356 struct cache_dfs_tgt *t;
358 t = kmalloc(sizeof(*t), GFP_ATOMIC);
360 return ERR_PTR(-ENOMEM);
361 t->name = kstrndup(name, strlen(name), GFP_ATOMIC);
364 return ERR_PTR(-ENOMEM);
366 t->path_consumed = path_consumed;
367 INIT_LIST_HEAD(&t->list);
372 * Copy DFS referral information to a cache entry and conditionally update
375 static int copy_ref_data(const struct dfs_info3_param *refs, int numrefs,
376 struct cache_entry *ce, const char *tgthint)
380 ce->ttl = refs[0].ttl;
381 ce->etime = get_expire_time(ce->ttl);
382 ce->srvtype = refs[0].server_type;
383 ce->hdr_flags = refs[0].flags;
384 ce->ref_flags = refs[0].ref_flag;
385 ce->path_consumed = refs[0].path_consumed;
387 for (i = 0; i < numrefs; i++) {
388 struct cache_dfs_tgt *t;
390 t = alloc_target(refs[i].node_name, refs[i].path_consumed);
395 if (tgthint && !strcasecmp(t->name, tgthint)) {
396 list_add(&t->list, &ce->tlist);
399 list_add_tail(&t->list, &ce->tlist);
404 ce->tgthint = list_first_entry_or_null(&ce->tlist,
405 struct cache_dfs_tgt, list);
410 /* Allocate a new cache entry */
411 static struct cache_entry *alloc_cache_entry(const char *path,
412 const struct dfs_info3_param *refs,
415 struct cache_entry *ce;
418 ce = kmem_cache_zalloc(cache_slab, GFP_KERNEL);
420 return ERR_PTR(-ENOMEM);
422 ce->path = kstrndup(path, strlen(path), GFP_KERNEL);
424 kmem_cache_free(cache_slab, ce);
425 return ERR_PTR(-ENOMEM);
427 INIT_HLIST_NODE(&ce->hlist);
428 INIT_LIST_HEAD(&ce->tlist);
430 rc = copy_ref_data(refs, numrefs, ce, NULL);
433 kmem_cache_free(cache_slab, ce);
439 /* Must be called with htable_rw_lock held */
440 static void remove_oldest_entry(void)
443 struct cache_entry *ce;
444 struct cache_entry *to_del = NULL;
446 for (i = 0; i < CACHE_HTABLE_SIZE; i++) {
447 struct hlist_head *l = &cache_htable[i];
449 hlist_for_each_entry(ce, l, hlist) {
450 if (hlist_unhashed(&ce->hlist))
452 if (!to_del || timespec64_compare(&ce->etime,
459 cifs_dbg(FYI, "%s: no entry to remove\n", __func__);
463 cifs_dbg(FYI, "%s: removing entry\n", __func__);
465 flush_cache_ent(to_del);
468 /* Add a new DFS cache entry */
469 static int add_cache_entry(const char *path, unsigned int hash,
470 struct dfs_info3_param *refs, int numrefs)
472 struct cache_entry *ce;
474 ce = alloc_cache_entry(path, refs, numrefs);
478 spin_lock(&cache_ttl_lock);
481 queue_delayed_work(dfscache_wq, &refresh_task, cache_ttl * HZ);
483 cache_ttl = min_t(int, cache_ttl, ce->ttl);
484 mod_delayed_work(dfscache_wq, &refresh_task, cache_ttl * HZ);
486 spin_unlock(&cache_ttl_lock);
488 down_write(&htable_rw_lock);
489 hlist_add_head(&ce->hlist, &cache_htable[hash]);
491 up_write(&htable_rw_lock);
496 static struct cache_entry *__lookup_cache_entry(const char *path)
498 struct cache_entry *ce;
502 h = cache_entry_hash(path, strlen(path));
504 hlist_for_each_entry(ce, &cache_htable[h], hlist) {
505 if (!strcasecmp(path, ce->path)) {
513 ce = ERR_PTR(-ENOENT);
518 * Find a DFS cache entry in hash table and optionally check prefix path against
520 * Use whole path components in the match.
521 * Must be called with htable_rw_lock held.
523 * Return ERR_PTR(-ENOENT) if the entry is not found.
525 static struct cache_entry *lookup_cache_entry(const char *path, unsigned int *hash)
527 struct cache_entry *ce = ERR_PTR(-ENOENT);
534 npath = kstrndup(path, strlen(path), GFP_KERNEL);
536 return ERR_PTR(-ENOMEM);
540 while ((s = strchr(s, sep)) && ++cnt < 3)
544 h = cache_entry_hash(path, strlen(path));
545 ce = __lookup_cache_entry(path);
549 * Handle paths that have more than two path components and are a complete prefix of the DFS
550 * referral request path (@path).
552 * See MS-DFSC 3.2.5.5 "Receiving a Root Referral Request or Link Referral Request".
554 h = cache_entry_hash(npath, strlen(npath));
555 e = npath + strlen(npath) - 1;
559 /* skip separators */
560 while (e > s && *e == sep)
568 ce = __lookup_cache_entry(npath);
570 h = cache_entry_hash(npath, strlen(npath));
575 /* backward until separator */
576 while (e > s && *e != sep)
586 static void __vol_release(struct vol_info *vi)
590 smb3_cleanup_fs_context_contents(&vi->ctx);
594 static void vol_release(struct kref *kref)
596 struct vol_info *vi = container_of(kref, struct vol_info, refcnt);
598 spin_lock(&vol_list_lock);
600 spin_unlock(&vol_list_lock);
604 static inline void free_vol_list(void)
606 struct vol_info *vi, *nvi;
608 list_for_each_entry_safe(vi, nvi, &vol_list, list) {
609 list_del_init(&vi->list);
615 * dfs_cache_destroy - destroy DFS referral cache
617 void dfs_cache_destroy(void)
619 cancel_delayed_work_sync(&refresh_task);
620 unload_nls(cache_nlsc);
623 kmem_cache_destroy(cache_slab);
624 destroy_workqueue(dfscache_wq);
626 cifs_dbg(FYI, "%s: destroyed DFS referral cache\n", __func__);
629 /* Must be called with htable_rw_lock held */
630 static int __update_cache_entry(const char *path,
631 const struct dfs_info3_param *refs,
635 struct cache_entry *ce;
638 ce = lookup_cache_entry(path, NULL);
643 s = ce->tgthint->name;
644 th = kstrndup(s, strlen(s), GFP_ATOMIC);
652 rc = copy_ref_data(refs, numrefs, ce, th);
659 static int get_dfs_referral(const unsigned int xid, struct cifs_ses *ses,
660 const struct nls_table *nls_codepage, int remap,
661 const char *path, struct dfs_info3_param **refs,
664 cifs_dbg(FYI, "%s: get an DFS referral for %s\n", __func__, path);
666 if (!ses || !ses->server || !ses->server->ops->get_dfs_refer)
668 if (unlikely(!nls_codepage))
674 return ses->server->ops->get_dfs_refer(xid, ses, path, refs, numrefs,
675 nls_codepage, remap);
678 /* Update an expired cache entry by getting a new DFS referral from server */
679 static int update_cache_entry(const char *path,
680 const struct dfs_info3_param *refs,
686 down_write(&htable_rw_lock);
687 rc = __update_cache_entry(path, refs, numrefs);
688 up_write(&htable_rw_lock);
694 * Find, create or update a DFS cache entry.
696 * If the entry wasn't found, it will create a new one. Or if it was found but
697 * expired, then it will update the entry accordingly.
699 * For interlinks, __cifs_dfs_mount() and expand_dfs_referral() are supposed to
700 * handle them properly.
702 static int __dfs_cache_find(const unsigned int xid, struct cifs_ses *ses,
703 const struct nls_table *nls_codepage, int remap,
704 const char *path, bool noreq)
708 struct cache_entry *ce;
709 struct dfs_info3_param *refs = NULL;
713 cifs_dbg(FYI, "%s: search path: %s\n", __func__, path);
715 down_read(&htable_rw_lock);
717 ce = lookup_cache_entry(path, &hash);
720 * If @noreq is set, no requests will be sent to the server. Just return
724 up_read(&htable_rw_lock);
725 return PTR_ERR_OR_ZERO(ce);
729 if (!cache_entry_expired(ce)) {
731 up_read(&htable_rw_lock);
738 up_read(&htable_rw_lock);
741 * No entry was found.
743 * Request a new DFS referral in order to create a new cache entry, or
744 * updating an existing one.
746 rc = get_dfs_referral(xid, ses, nls_codepage, remap, path,
751 dump_refs(refs, numrefs);
754 rc = update_cache_entry(path, refs, numrefs);
758 if (atomic_read(&cache_count) >= CACHE_MAX_ENTRIES) {
759 cifs_dbg(FYI, "%s: reached max cache size (%d)\n",
760 __func__, CACHE_MAX_ENTRIES);
761 down_write(&htable_rw_lock);
762 remove_oldest_entry();
763 up_write(&htable_rw_lock);
766 rc = add_cache_entry(path, hash, refs, numrefs);
768 atomic_inc(&cache_count);
771 free_dfs_info_array(refs, numrefs);
776 * Set up a DFS referral from a given cache entry.
778 * Must be called with htable_rw_lock held.
780 static int setup_referral(const char *path, struct cache_entry *ce,
781 struct dfs_info3_param *ref, const char *target)
785 cifs_dbg(FYI, "%s: set up new ref\n", __func__);
787 memset(ref, 0, sizeof(*ref));
789 ref->path_name = kstrndup(path, strlen(path), GFP_ATOMIC);
793 ref->node_name = kstrndup(target, strlen(target), GFP_ATOMIC);
794 if (!ref->node_name) {
799 ref->path_consumed = ce->path_consumed;
801 ref->server_type = ce->srvtype;
802 ref->ref_flag = ce->ref_flags;
803 ref->flags = ce->hdr_flags;
808 kfree(ref->path_name);
809 ref->path_name = NULL;
813 /* Return target list of a DFS cache entry */
814 static int get_targets(struct cache_entry *ce, struct dfs_cache_tgt_list *tl)
817 struct list_head *head = &tl->tl_list;
818 struct cache_dfs_tgt *t;
819 struct dfs_cache_tgt_iterator *it, *nit;
821 memset(tl, 0, sizeof(*tl));
822 INIT_LIST_HEAD(head);
824 list_for_each_entry(t, &ce->tlist, list) {
825 it = kzalloc(sizeof(*it), GFP_ATOMIC);
831 it->it_name = kstrndup(t->name, strlen(t->name), GFP_ATOMIC);
837 it->it_path_consumed = t->path_consumed;
839 if (ce->tgthint == t)
840 list_add(&it->it_list, head);
842 list_add_tail(&it->it_list, head);
845 tl->tl_numtgts = ce->numtgts;
850 list_for_each_entry_safe(it, nit, head, it_list) {
858 * dfs_cache_find - find a DFS cache entry
860 * If it doesn't find the cache entry, then it will get a DFS referral
861 * for @path and create a new entry.
863 * In case the cache entry exists but expired, it will get a DFS referral
864 * for @path and then update the respective cache entry.
866 * These parameters are passed down to the get_dfs_refer() call if it
867 * needs to be issued:
869 * @ses: smb session to issue the request on
870 * @nls_codepage: charset conversion
871 * @remap: path character remapping type
872 * @path: path to lookup in DFS referral cache.
874 * @ref: when non-NULL, store single DFS referral result in it.
875 * @tgt_list: when non-NULL, store complete DFS target list in it.
877 * Return zero if the target was found, otherwise non-zero.
879 int dfs_cache_find(const unsigned int xid, struct cifs_ses *ses,
880 const struct nls_table *nls_codepage, int remap,
881 const char *path, struct dfs_info3_param *ref,
882 struct dfs_cache_tgt_list *tgt_list)
886 struct cache_entry *ce;
888 rc = get_normalized_path(path, &npath);
892 rc = __dfs_cache_find(xid, ses, nls_codepage, remap, npath, false);
896 down_read(&htable_rw_lock);
898 ce = lookup_cache_entry(npath, NULL);
900 up_read(&htable_rw_lock);
906 rc = setup_referral(path, ce, ref, get_tgt_name(ce));
910 rc = get_targets(ce, tgt_list);
912 up_read(&htable_rw_lock);
915 free_normalized_path(path, npath);
920 * dfs_cache_noreq_find - find a DFS cache entry without sending any requests to
921 * the currently connected server.
923 * NOTE: This function will neither update a cache entry in case it was
924 * expired, nor create a new cache entry if @path hasn't been found. It heavily
925 * relies on an existing cache entry.
927 * @path: path to lookup in the DFS referral cache.
928 * @ref: when non-NULL, store single DFS referral result in it.
929 * @tgt_list: when non-NULL, store complete DFS target list in it.
931 * Return 0 if successful.
932 * Return -ENOENT if the entry was not found.
933 * Return non-zero for other errors.
935 int dfs_cache_noreq_find(const char *path, struct dfs_info3_param *ref,
936 struct dfs_cache_tgt_list *tgt_list)
940 struct cache_entry *ce;
942 rc = get_normalized_path(path, &npath);
946 cifs_dbg(FYI, "%s: path: %s\n", __func__, npath);
948 down_read(&htable_rw_lock);
950 ce = lookup_cache_entry(npath, NULL);
957 rc = setup_referral(path, ce, ref, get_tgt_name(ce));
961 rc = get_targets(ce, tgt_list);
964 up_read(&htable_rw_lock);
965 free_normalized_path(path, npath);
971 * dfs_cache_update_tgthint - update target hint of a DFS cache entry
973 * If it doesn't find the cache entry, then it will get a DFS referral for @path
974 * and create a new entry.
976 * In case the cache entry exists but expired, it will get a DFS referral
977 * for @path and then update the respective cache entry.
981 * @nls_codepage: charset conversion
982 * @remap: type of character remapping for paths
983 * @path: path to lookup in DFS referral cache.
984 * @it: DFS target iterator
986 * Return zero if the target hint was updated successfully, otherwise non-zero.
988 int dfs_cache_update_tgthint(const unsigned int xid, struct cifs_ses *ses,
989 const struct nls_table *nls_codepage, int remap,
991 const struct dfs_cache_tgt_iterator *it)
995 struct cache_entry *ce;
996 struct cache_dfs_tgt *t;
998 rc = get_normalized_path(path, &npath);
1002 cifs_dbg(FYI, "%s: update target hint - path: %s\n", __func__, npath);
1004 rc = __dfs_cache_find(xid, ses, nls_codepage, remap, npath, false);
1008 down_write(&htable_rw_lock);
1010 ce = lookup_cache_entry(npath, NULL);
1018 if (likely(!strcasecmp(it->it_name, t->name)))
1021 list_for_each_entry(t, &ce->tlist, list) {
1022 if (!strcasecmp(t->name, it->it_name)) {
1024 cifs_dbg(FYI, "%s: new target hint: %s\n", __func__,
1031 up_write(&htable_rw_lock);
1033 free_normalized_path(path, npath);
1039 * dfs_cache_noreq_update_tgthint - update target hint of a DFS cache entry
1040 * without sending any requests to the currently connected server.
1042 * NOTE: This function will neither update a cache entry in case it was
1043 * expired, nor create a new cache entry if @path hasn't been found. It heavily
1044 * relies on an existing cache entry.
1046 * @path: path to lookup in DFS referral cache.
1047 * @it: target iterator which contains the target hint to update the cache
1050 * Return zero if the target hint was updated successfully, otherwise non-zero.
1052 int dfs_cache_noreq_update_tgthint(const char *path,
1053 const struct dfs_cache_tgt_iterator *it)
1057 struct cache_entry *ce;
1058 struct cache_dfs_tgt *t;
1063 rc = get_normalized_path(path, &npath);
1067 cifs_dbg(FYI, "%s: path: %s\n", __func__, npath);
1069 down_write(&htable_rw_lock);
1071 ce = lookup_cache_entry(npath, NULL);
1080 if (unlikely(!strcasecmp(it->it_name, t->name)))
1083 list_for_each_entry(t, &ce->tlist, list) {
1084 if (!strcasecmp(t->name, it->it_name)) {
1086 cifs_dbg(FYI, "%s: new target hint: %s\n", __func__,
1093 up_write(&htable_rw_lock);
1094 free_normalized_path(path, npath);
1100 * dfs_cache_get_tgt_referral - returns a DFS referral (@ref) from a given
1101 * target iterator (@it).
1103 * @path: path to lookup in DFS referral cache.
1104 * @it: DFS target iterator.
1105 * @ref: DFS referral pointer to set up the gathered information.
1107 * Return zero if the DFS referral was set up correctly, otherwise non-zero.
1109 int dfs_cache_get_tgt_referral(const char *path,
1110 const struct dfs_cache_tgt_iterator *it,
1111 struct dfs_info3_param *ref)
1115 struct cache_entry *ce;
1120 rc = get_normalized_path(path, &npath);
1124 cifs_dbg(FYI, "%s: path: %s\n", __func__, npath);
1126 down_read(&htable_rw_lock);
1128 ce = lookup_cache_entry(npath, NULL);
1134 cifs_dbg(FYI, "%s: target name: %s\n", __func__, it->it_name);
1136 rc = setup_referral(path, ce, ref, it->it_name);
1139 up_read(&htable_rw_lock);
1140 free_normalized_path(path, npath);
1146 * dfs_cache_add_vol - add a cifs context during mount() that will be handled by
1147 * DFS cache refresh worker.
1149 * @mntdata: mount data.
1150 * @ctx: cifs context.
1151 * @fullpath: origin full path.
1153 * Return zero if context was set up correctly, otherwise non-zero.
1155 int dfs_cache_add_vol(char *mntdata, struct smb3_fs_context *ctx, const char *fullpath)
1158 struct vol_info *vi;
1160 if (!ctx || !fullpath || !mntdata)
1163 cifs_dbg(FYI, "%s: fullpath: %s\n", __func__, fullpath);
1165 vi = kzalloc(sizeof(*vi), GFP_KERNEL);
1169 vi->fullpath = kstrndup(fullpath, strlen(fullpath), GFP_KERNEL);
1170 if (!vi->fullpath) {
1175 rc = smb3_fs_context_dup(&vi->ctx, ctx);
1177 goto err_free_fullpath;
1179 vi->mntdata = mntdata;
1180 spin_lock_init(&vi->ctx_lock);
1181 kref_init(&vi->refcnt);
1183 spin_lock(&vol_list_lock);
1184 list_add_tail(&vi->list, &vol_list);
1185 spin_unlock(&vol_list_lock);
1190 kfree(vi->fullpath);
1196 /* Must be called with vol_list_lock held */
1197 static struct vol_info *find_vol(const char *fullpath)
1199 struct vol_info *vi;
1201 list_for_each_entry(vi, &vol_list, list) {
1202 cifs_dbg(FYI, "%s: vi->fullpath: %s\n", __func__, vi->fullpath);
1203 if (!strcasecmp(vi->fullpath, fullpath))
1206 return ERR_PTR(-ENOENT);
1210 * dfs_cache_update_vol - update vol info in DFS cache after failover
1212 * @fullpath: fullpath to look up in volume list.
1213 * @server: TCP ses pointer.
1215 * Return zero if volume was updated, otherwise non-zero.
1217 int dfs_cache_update_vol(const char *fullpath, struct TCP_Server_Info *server)
1219 struct vol_info *vi;
1221 if (!fullpath || !server)
1224 cifs_dbg(FYI, "%s: fullpath: %s\n", __func__, fullpath);
1226 spin_lock(&vol_list_lock);
1227 vi = find_vol(fullpath);
1229 spin_unlock(&vol_list_lock);
1232 kref_get(&vi->refcnt);
1233 spin_unlock(&vol_list_lock);
1235 cifs_dbg(FYI, "%s: updating volume info\n", __func__);
1236 spin_lock(&vi->ctx_lock);
1237 memcpy(&vi->ctx.dstaddr, &server->dstaddr,
1238 sizeof(vi->ctx.dstaddr));
1239 spin_unlock(&vi->ctx_lock);
1241 kref_put(&vi->refcnt, vol_release);
1247 * dfs_cache_del_vol - remove volume info in DFS cache during umount()
1249 * @fullpath: fullpath to look up in volume list.
1251 void dfs_cache_del_vol(const char *fullpath)
1253 struct vol_info *vi;
1255 if (!fullpath || !*fullpath)
1258 cifs_dbg(FYI, "%s: fullpath: %s\n", __func__, fullpath);
1260 spin_lock(&vol_list_lock);
1261 vi = find_vol(fullpath);
1262 spin_unlock(&vol_list_lock);
1265 kref_put(&vi->refcnt, vol_release);
1269 * dfs_cache_get_tgt_share - parse a DFS target
1271 * @path: DFS full path
1272 * @it: DFS target iterator.
1273 * @share: tree name.
1274 * @prefix: prefix path.
1276 * Return zero if target was parsed correctly, otherwise non-zero.
1278 int dfs_cache_get_tgt_share(char *path, const struct dfs_cache_tgt_iterator *it,
1279 char **share, char **prefix)
1283 size_t plen1, plen2;
1285 if (!it || !path || !share || !prefix || strlen(path) < it->it_path_consumed)
1291 sep = it->it_name[0];
1292 if (sep != '\\' && sep != '/')
1295 s = strchr(it->it_name + 1, sep);
1299 /* point to prefix in target node */
1300 s = strchrnul(s + 1, sep);
1302 /* extract target share */
1303 *share = kstrndup(it->it_name, s - it->it_name, GFP_KERNEL);
1307 /* skip separator */
1310 /* point to prefix in DFS path */
1311 p = path + it->it_path_consumed;
1315 /* merge prefix paths from DFS path and target node */
1316 plen1 = it->it_name + strlen(it->it_name) - s;
1317 plen2 = path + strlen(path) - p;
1318 if (plen1 || plen2) {
1319 len = plen1 + plen2 + 2;
1320 *prefix = kmalloc(len, GFP_KERNEL);
1327 scnprintf(*prefix, len, "%.*s%c%.*s", (int)plen1, s, sep, (int)plen2, p);
1329 strscpy(*prefix, p, len);
1334 /* Get all tcons that are within a DFS namespace and can be refreshed */
1335 static void get_tcons(struct TCP_Server_Info *server, struct list_head *head)
1337 struct cifs_ses *ses;
1338 struct cifs_tcon *tcon;
1340 INIT_LIST_HEAD(head);
1342 spin_lock(&cifs_tcp_ses_lock);
1343 list_for_each_entry(ses, &server->smb_ses_list, smb_ses_list) {
1344 list_for_each_entry(tcon, &ses->tcon_list, tcon_list) {
1345 if (!tcon->need_reconnect && !tcon->need_reopen_files &&
1348 list_add_tail(&tcon->ulist, head);
1351 if (ses->tcon_ipc && !ses->tcon_ipc->need_reconnect &&
1352 ses->tcon_ipc->dfs_path) {
1353 list_add_tail(&ses->tcon_ipc->ulist, head);
1356 spin_unlock(&cifs_tcp_ses_lock);
1359 static bool is_dfs_link(const char *path)
1363 s = strchr(path + 1, '\\');
1366 return !!strchr(s + 1, '\\');
1369 static char *get_dfs_root(const char *path)
1373 s = strchr(path + 1, '\\');
1375 return ERR_PTR(-EINVAL);
1377 s = strchr(s + 1, '\\');
1379 return ERR_PTR(-EINVAL);
1381 npath = kstrndup(path, s - path, GFP_KERNEL);
1383 return ERR_PTR(-ENOMEM);
1388 static inline void put_tcp_server(struct TCP_Server_Info *server)
1390 cifs_put_tcp_session(server, 0);
1393 static struct TCP_Server_Info *get_tcp_server(struct smb3_fs_context *ctx)
1395 struct TCP_Server_Info *server;
1397 server = cifs_find_tcp_session(ctx);
1398 if (IS_ERR_OR_NULL(server))
1401 spin_lock(&GlobalMid_Lock);
1402 if (server->tcpStatus != CifsGood) {
1403 spin_unlock(&GlobalMid_Lock);
1404 put_tcp_server(server);
1407 spin_unlock(&GlobalMid_Lock);
1412 /* Find root SMB session out of a DFS link path */
1413 static struct cifs_ses *find_root_ses(struct vol_info *vi,
1414 struct cifs_tcon *tcon,
1419 struct cache_entry *ce;
1420 struct dfs_info3_param ref = {0};
1421 char *mdata = NULL, *devname = NULL;
1422 struct TCP_Server_Info *server;
1423 struct cifs_ses *ses;
1424 struct smb3_fs_context ctx = {NULL};
1426 rpath = get_dfs_root(path);
1428 return ERR_CAST(rpath);
1430 down_read(&htable_rw_lock);
1432 ce = lookup_cache_entry(rpath, NULL);
1434 up_read(&htable_rw_lock);
1439 rc = setup_referral(path, ce, &ref, get_tgt_name(ce));
1441 up_read(&htable_rw_lock);
1446 up_read(&htable_rw_lock);
1448 mdata = cifs_compose_mount_options(vi->mntdata, rpath, &ref,
1450 free_dfs_info_param(&ref);
1452 if (IS_ERR(mdata)) {
1453 ses = ERR_CAST(mdata);
1458 rc = cifs_setup_volume_info(&ctx, NULL, devname);
1465 server = get_tcp_server(&ctx);
1467 ses = ERR_PTR(-EHOSTDOWN);
1471 ses = cifs_get_smb_ses(server, &ctx);
1474 smb3_cleanup_fs_context_contents(&ctx);
1482 /* Refresh DFS cache entry from a given tcon */
1483 static int refresh_tcon(struct vol_info *vi, struct cifs_tcon *tcon)
1488 struct cache_entry *ce;
1489 struct cifs_ses *root_ses = NULL, *ses;
1490 struct dfs_info3_param *refs = NULL;
1495 path = tcon->dfs_path + 1;
1497 rc = get_normalized_path(path, &npath);
1501 down_read(&htable_rw_lock);
1503 ce = lookup_cache_entry(npath, NULL);
1506 up_read(&htable_rw_lock);
1510 if (!cache_entry_expired(ce)) {
1511 up_read(&htable_rw_lock);
1515 up_read(&htable_rw_lock);
1517 /* If it's a DFS Link, then use root SMB session for refreshing it */
1518 if (is_dfs_link(npath)) {
1519 ses = root_ses = find_root_ses(vi, tcon, npath);
1529 rc = get_dfs_referral(xid, ses, cache_nlsc, tcon->remap, npath, &refs,
1532 dump_refs(refs, numrefs);
1533 rc = update_cache_entry(npath, refs, numrefs);
1534 free_dfs_info_array(refs, numrefs);
1538 cifs_put_smb_ses(root_ses);
1541 free_normalized_path(path, npath);
1549 * Worker that will refresh DFS cache based on lowest TTL value from a DFS
1552 static void refresh_cache_worker(struct work_struct *work)
1554 struct vol_info *vi, *nvi;
1555 struct TCP_Server_Info *server;
1558 struct cifs_tcon *tcon, *ntcon;
1562 * Find SMB volumes that are eligible (server->tcpStatus == CifsGood)
1565 spin_lock(&vol_list_lock);
1566 list_for_each_entry(vi, &vol_list, list) {
1567 server = get_tcp_server(&vi->ctx);
1571 kref_get(&vi->refcnt);
1572 list_add_tail(&vi->rlist, &vols);
1573 put_tcp_server(server);
1575 spin_unlock(&vol_list_lock);
1577 /* Walk through all TCONs and refresh any expired cache entry */
1578 list_for_each_entry_safe(vi, nvi, &vols, rlist) {
1579 spin_lock(&vi->ctx_lock);
1580 server = get_tcp_server(&vi->ctx);
1581 spin_unlock(&vi->ctx_lock);
1586 get_tcons(server, &tcons);
1589 list_for_each_entry_safe(tcon, ntcon, &tcons, ulist) {
1591 * Skip tcp server if any of its tcons failed to refresh
1592 * (possibily due to reconnects).
1595 rc = refresh_tcon(vi, tcon);
1597 list_del_init(&tcon->ulist);
1598 cifs_put_tcon(tcon);
1601 put_tcp_server(server);
1604 list_del_init(&vi->rlist);
1605 kref_put(&vi->refcnt, vol_release);
1608 spin_lock(&cache_ttl_lock);
1609 queue_delayed_work(dfscache_wq, &refresh_task, cache_ttl * HZ);
1610 spin_unlock(&cache_ttl_lock);