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;
43 struct timespec64 etime;
46 struct list_head tlist;
47 struct cache_dfs_tgt *tgthint;
53 struct smb3_fs_context ctx;
55 struct list_head list;
56 struct list_head rlist;
60 static struct kmem_cache *cache_slab __read_mostly;
61 static struct workqueue_struct *dfscache_wq __read_mostly;
64 static DEFINE_SPINLOCK(cache_ttl_lock);
66 static struct nls_table *cache_nlsc;
69 * Number of entries in the cache
71 static atomic_t cache_count;
73 static struct hlist_head cache_htable[CACHE_HTABLE_SIZE];
74 static DECLARE_RWSEM(htable_rw_lock);
76 static LIST_HEAD(vol_list);
77 static DEFINE_SPINLOCK(vol_list_lock);
79 static void refresh_cache_worker(struct work_struct *work);
81 static DECLARE_DELAYED_WORK(refresh_task, refresh_cache_worker);
83 static int get_normalized_path(const char *path, char **npath)
85 if (!path || strlen(path) < 3 || (*path != '\\' && *path != '/'))
89 *npath = (char *)path;
91 *npath = kstrndup(path, strlen(path), GFP_KERNEL);
94 convert_delimiter(*npath, '\\');
99 static inline void free_normalized_path(const char *path, char *npath)
105 static inline bool cache_entry_expired(const struct cache_entry *ce)
107 struct timespec64 ts;
109 ktime_get_coarse_real_ts64(&ts);
110 return timespec64_compare(&ts, &ce->etime) >= 0;
113 static inline void free_tgts(struct cache_entry *ce)
115 struct cache_dfs_tgt *t, *n;
117 list_for_each_entry_safe(t, n, &ce->tlist, list) {
124 static inline void flush_cache_ent(struct cache_entry *ce)
126 hlist_del_init(&ce->hlist);
129 atomic_dec(&cache_count);
130 kmem_cache_free(cache_slab, ce);
133 static void flush_cache_ents(void)
137 for (i = 0; i < CACHE_HTABLE_SIZE; i++) {
138 struct hlist_head *l = &cache_htable[i];
139 struct hlist_node *n;
140 struct cache_entry *ce;
142 hlist_for_each_entry_safe(ce, n, l, hlist) {
143 if (!hlist_unhashed(&ce->hlist))
150 * dfs cache /proc file
152 static int dfscache_proc_show(struct seq_file *m, void *v)
155 struct cache_entry *ce;
156 struct cache_dfs_tgt *t;
158 seq_puts(m, "DFS cache\n---------\n");
160 down_read(&htable_rw_lock);
161 for (i = 0; i < CACHE_HTABLE_SIZE; i++) {
162 struct hlist_head *l = &cache_htable[i];
164 hlist_for_each_entry(ce, l, hlist) {
165 if (hlist_unhashed(&ce->hlist))
169 "cache entry: path=%s,type=%s,ttl=%d,etime=%ld,"
170 "interlink=%s,path_consumed=%d,expired=%s\n",
172 ce->srvtype == DFS_TYPE_ROOT ? "root" : "link",
173 ce->ttl, ce->etime.tv_nsec,
174 IS_INTERLINK_SET(ce->flags) ? "yes" : "no",
176 cache_entry_expired(ce) ? "yes" : "no");
178 list_for_each_entry(t, &ce->tlist, list) {
179 seq_printf(m, " %s%s\n",
181 ce->tgthint == t ? " (target hint)" : "");
185 up_read(&htable_rw_lock);
190 static ssize_t dfscache_proc_write(struct file *file, const char __user *buffer,
191 size_t count, loff_t *ppos)
196 rc = get_user(c, buffer);
203 cifs_dbg(FYI, "clearing dfs cache\n");
205 down_write(&htable_rw_lock);
207 up_write(&htable_rw_lock);
212 static int dfscache_proc_open(struct inode *inode, struct file *file)
214 return single_open(file, dfscache_proc_show, NULL);
217 const struct proc_ops dfscache_proc_ops = {
218 .proc_open = dfscache_proc_open,
219 .proc_read = seq_read,
220 .proc_lseek = seq_lseek,
221 .proc_release = single_release,
222 .proc_write = dfscache_proc_write,
225 #ifdef CONFIG_CIFS_DEBUG2
226 static inline void dump_tgts(const struct cache_entry *ce)
228 struct cache_dfs_tgt *t;
230 cifs_dbg(FYI, "target list:\n");
231 list_for_each_entry(t, &ce->tlist, list) {
232 cifs_dbg(FYI, " %s%s\n", t->name,
233 ce->tgthint == t ? " (target hint)" : "");
237 static inline void dump_ce(const struct cache_entry *ce)
239 cifs_dbg(FYI, "cache entry: path=%s,type=%s,ttl=%d,etime=%ld,interlink=%s,path_consumed=%d,expired=%s\n",
241 ce->srvtype == DFS_TYPE_ROOT ? "root" : "link", ce->ttl,
243 IS_INTERLINK_SET(ce->flags) ? "yes" : "no",
245 cache_entry_expired(ce) ? "yes" : "no");
249 static inline void dump_refs(const struct dfs_info3_param *refs, int numrefs)
253 cifs_dbg(FYI, "DFS referrals returned by the server:\n");
254 for (i = 0; i < numrefs; i++) {
255 const struct dfs_info3_param *ref = &refs[i];
260 "path_consumed: %d\n"
261 "server_type: 0x%x\n"
266 ref->flags, ref->path_consumed, ref->server_type,
267 ref->ref_flag, ref->path_name, ref->node_name,
268 ref->ttl, ref->ttl / 60);
274 #define dump_refs(r, n)
278 * dfs_cache_init - Initialize DFS referral cache.
280 * Return zero if initialized successfully, otherwise non-zero.
282 int dfs_cache_init(void)
287 dfscache_wq = alloc_workqueue("cifs-dfscache",
288 WQ_FREEZABLE | WQ_MEM_RECLAIM, 1);
292 cache_slab = kmem_cache_create("cifs_dfs_cache",
293 sizeof(struct cache_entry), 0,
294 SLAB_HWCACHE_ALIGN, NULL);
300 for (i = 0; i < CACHE_HTABLE_SIZE; i++)
301 INIT_HLIST_HEAD(&cache_htable[i]);
303 atomic_set(&cache_count, 0);
304 cache_nlsc = load_nls_default();
306 cifs_dbg(FYI, "%s: initialized DFS referral cache\n", __func__);
310 destroy_workqueue(dfscache_wq);
314 static inline unsigned int cache_entry_hash(const void *data, int size)
318 h = jhash(data, size, 0);
319 return h & (CACHE_HTABLE_SIZE - 1);
322 /* Check whether second path component of @path is SYSVOL or NETLOGON */
323 static inline bool is_sysvol_or_netlogon(const char *path)
328 s = strchr(path + 1, sep) + 1;
329 return !strncasecmp(s, "sysvol", strlen("sysvol")) ||
330 !strncasecmp(s, "netlogon", strlen("netlogon"));
333 /* Return target hint of a DFS cache entry */
334 static inline char *get_tgt_name(const struct cache_entry *ce)
336 struct cache_dfs_tgt *t = ce->tgthint;
338 return t ? t->name : ERR_PTR(-ENOENT);
341 /* Return expire time out of a new entry's TTL */
342 static inline struct timespec64 get_expire_time(int ttl)
344 struct timespec64 ts = {
348 struct timespec64 now;
350 ktime_get_coarse_real_ts64(&now);
351 return timespec64_add(now, ts);
354 /* Allocate a new DFS target */
355 static struct cache_dfs_tgt *alloc_target(const char *name, int path_consumed)
357 struct cache_dfs_tgt *t;
359 t = kmalloc(sizeof(*t), GFP_ATOMIC);
361 return ERR_PTR(-ENOMEM);
362 t->name = kstrndup(name, strlen(name), GFP_ATOMIC);
365 return ERR_PTR(-ENOMEM);
367 t->path_consumed = path_consumed;
368 INIT_LIST_HEAD(&t->list);
373 * Copy DFS referral information to a cache entry and conditionally update
376 static int copy_ref_data(const struct dfs_info3_param *refs, int numrefs,
377 struct cache_entry *ce, const char *tgthint)
381 ce->ttl = refs[0].ttl;
382 ce->etime = get_expire_time(ce->ttl);
383 ce->srvtype = refs[0].server_type;
384 ce->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->flags;
807 kfree(ref->path_name);
808 ref->path_name = NULL;
812 /* Return target list of a DFS cache entry */
813 static int get_targets(struct cache_entry *ce, struct dfs_cache_tgt_list *tl)
816 struct list_head *head = &tl->tl_list;
817 struct cache_dfs_tgt *t;
818 struct dfs_cache_tgt_iterator *it, *nit;
820 memset(tl, 0, sizeof(*tl));
821 INIT_LIST_HEAD(head);
823 list_for_each_entry(t, &ce->tlist, list) {
824 it = kzalloc(sizeof(*it), GFP_ATOMIC);
830 it->it_name = kstrndup(t->name, strlen(t->name), GFP_ATOMIC);
836 it->it_path_consumed = t->path_consumed;
838 if (ce->tgthint == t)
839 list_add(&it->it_list, head);
841 list_add_tail(&it->it_list, head);
844 tl->tl_numtgts = ce->numtgts;
849 list_for_each_entry_safe(it, nit, head, it_list) {
857 * dfs_cache_find - find a DFS cache entry
859 * If it doesn't find the cache entry, then it will get a DFS referral
860 * for @path and create a new entry.
862 * In case the cache entry exists but expired, it will get a DFS referral
863 * for @path and then update the respective cache entry.
865 * These parameters are passed down to the get_dfs_refer() call if it
866 * needs to be issued:
868 * @ses: smb session to issue the request on
869 * @nls_codepage: charset conversion
870 * @remap: path character remapping type
871 * @path: path to lookup in DFS referral cache.
873 * @ref: when non-NULL, store single DFS referral result in it.
874 * @tgt_list: when non-NULL, store complete DFS target list in it.
876 * Return zero if the target was found, otherwise non-zero.
878 int dfs_cache_find(const unsigned int xid, struct cifs_ses *ses,
879 const struct nls_table *nls_codepage, int remap,
880 const char *path, struct dfs_info3_param *ref,
881 struct dfs_cache_tgt_list *tgt_list)
885 struct cache_entry *ce;
887 rc = get_normalized_path(path, &npath);
891 rc = __dfs_cache_find(xid, ses, nls_codepage, remap, npath, false);
895 down_read(&htable_rw_lock);
897 ce = lookup_cache_entry(npath, NULL);
899 up_read(&htable_rw_lock);
905 rc = setup_referral(path, ce, ref, get_tgt_name(ce));
909 rc = get_targets(ce, tgt_list);
911 up_read(&htable_rw_lock);
914 free_normalized_path(path, npath);
919 * dfs_cache_noreq_find - find a DFS cache entry without sending any requests to
920 * the currently connected server.
922 * NOTE: This function will neither update a cache entry in case it was
923 * expired, nor create a new cache entry if @path hasn't been found. It heavily
924 * relies on an existing cache entry.
926 * @path: path to lookup in the DFS referral cache.
927 * @ref: when non-NULL, store single DFS referral result in it.
928 * @tgt_list: when non-NULL, store complete DFS target list in it.
930 * Return 0 if successful.
931 * Return -ENOENT if the entry was not found.
932 * Return non-zero for other errors.
934 int dfs_cache_noreq_find(const char *path, struct dfs_info3_param *ref,
935 struct dfs_cache_tgt_list *tgt_list)
939 struct cache_entry *ce;
941 rc = get_normalized_path(path, &npath);
945 cifs_dbg(FYI, "%s: path: %s\n", __func__, npath);
947 down_read(&htable_rw_lock);
949 ce = lookup_cache_entry(npath, NULL);
956 rc = setup_referral(path, ce, ref, get_tgt_name(ce));
960 rc = get_targets(ce, tgt_list);
963 up_read(&htable_rw_lock);
964 free_normalized_path(path, npath);
970 * dfs_cache_update_tgthint - update target hint of a DFS cache entry
972 * If it doesn't find the cache entry, then it will get a DFS referral for @path
973 * and create a new entry.
975 * In case the cache entry exists but expired, it will get a DFS referral
976 * for @path and then update the respective cache entry.
980 * @nls_codepage: charset conversion
981 * @remap: type of character remapping for paths
982 * @path: path to lookup in DFS referral cache.
983 * @it: DFS target iterator
985 * Return zero if the target hint was updated successfully, otherwise non-zero.
987 int dfs_cache_update_tgthint(const unsigned int xid, struct cifs_ses *ses,
988 const struct nls_table *nls_codepage, int remap,
990 const struct dfs_cache_tgt_iterator *it)
994 struct cache_entry *ce;
995 struct cache_dfs_tgt *t;
997 rc = get_normalized_path(path, &npath);
1001 cifs_dbg(FYI, "%s: update target hint - path: %s\n", __func__, npath);
1003 rc = __dfs_cache_find(xid, ses, nls_codepage, remap, npath, false);
1007 down_write(&htable_rw_lock);
1009 ce = lookup_cache_entry(npath, NULL);
1017 if (likely(!strcasecmp(it->it_name, t->name)))
1020 list_for_each_entry(t, &ce->tlist, list) {
1021 if (!strcasecmp(t->name, it->it_name)) {
1023 cifs_dbg(FYI, "%s: new target hint: %s\n", __func__,
1030 up_write(&htable_rw_lock);
1032 free_normalized_path(path, npath);
1038 * dfs_cache_noreq_update_tgthint - update target hint of a DFS cache entry
1039 * without sending any requests to the currently connected server.
1041 * NOTE: This function will neither update a cache entry in case it was
1042 * expired, nor create a new cache entry if @path hasn't been found. It heavily
1043 * relies on an existing cache entry.
1045 * @path: path to lookup in DFS referral cache.
1046 * @it: target iterator which contains the target hint to update the cache
1049 * Return zero if the target hint was updated successfully, otherwise non-zero.
1051 int dfs_cache_noreq_update_tgthint(const char *path,
1052 const struct dfs_cache_tgt_iterator *it)
1056 struct cache_entry *ce;
1057 struct cache_dfs_tgt *t;
1062 rc = get_normalized_path(path, &npath);
1066 cifs_dbg(FYI, "%s: path: %s\n", __func__, npath);
1068 down_write(&htable_rw_lock);
1070 ce = lookup_cache_entry(npath, NULL);
1079 if (unlikely(!strcasecmp(it->it_name, t->name)))
1082 list_for_each_entry(t, &ce->tlist, list) {
1083 if (!strcasecmp(t->name, it->it_name)) {
1085 cifs_dbg(FYI, "%s: new target hint: %s\n", __func__,
1092 up_write(&htable_rw_lock);
1093 free_normalized_path(path, npath);
1099 * dfs_cache_get_tgt_referral - returns a DFS referral (@ref) from a given
1100 * target iterator (@it).
1102 * @path: path to lookup in DFS referral cache.
1103 * @it: DFS target iterator.
1104 * @ref: DFS referral pointer to set up the gathered information.
1106 * Return zero if the DFS referral was set up correctly, otherwise non-zero.
1108 int dfs_cache_get_tgt_referral(const char *path,
1109 const struct dfs_cache_tgt_iterator *it,
1110 struct dfs_info3_param *ref)
1114 struct cache_entry *ce;
1119 rc = get_normalized_path(path, &npath);
1123 cifs_dbg(FYI, "%s: path: %s\n", __func__, npath);
1125 down_read(&htable_rw_lock);
1127 ce = lookup_cache_entry(npath, NULL);
1133 cifs_dbg(FYI, "%s: target name: %s\n", __func__, it->it_name);
1135 rc = setup_referral(path, ce, ref, it->it_name);
1138 up_read(&htable_rw_lock);
1139 free_normalized_path(path, npath);
1145 * dfs_cache_add_vol - add a cifs context during mount() that will be handled by
1146 * DFS cache refresh worker.
1148 * @mntdata: mount data.
1149 * @ctx: cifs context.
1150 * @fullpath: origin full path.
1152 * Return zero if context was set up correctly, otherwise non-zero.
1154 int dfs_cache_add_vol(char *mntdata, struct smb3_fs_context *ctx, const char *fullpath)
1157 struct vol_info *vi;
1159 if (!ctx || !fullpath || !mntdata)
1162 cifs_dbg(FYI, "%s: fullpath: %s\n", __func__, fullpath);
1164 vi = kzalloc(sizeof(*vi), GFP_KERNEL);
1168 vi->fullpath = kstrndup(fullpath, strlen(fullpath), GFP_KERNEL);
1169 if (!vi->fullpath) {
1174 rc = smb3_fs_context_dup(&vi->ctx, ctx);
1176 goto err_free_fullpath;
1178 vi->mntdata = mntdata;
1179 spin_lock_init(&vi->ctx_lock);
1180 kref_init(&vi->refcnt);
1182 spin_lock(&vol_list_lock);
1183 list_add_tail(&vi->list, &vol_list);
1184 spin_unlock(&vol_list_lock);
1189 kfree(vi->fullpath);
1195 /* Must be called with vol_list_lock held */
1196 static struct vol_info *find_vol(const char *fullpath)
1198 struct vol_info *vi;
1200 list_for_each_entry(vi, &vol_list, list) {
1201 cifs_dbg(FYI, "%s: vi->fullpath: %s\n", __func__, vi->fullpath);
1202 if (!strcasecmp(vi->fullpath, fullpath))
1205 return ERR_PTR(-ENOENT);
1209 * dfs_cache_update_vol - update vol info in DFS cache after failover
1211 * @fullpath: fullpath to look up in volume list.
1212 * @server: TCP ses pointer.
1214 * Return zero if volume was updated, otherwise non-zero.
1216 int dfs_cache_update_vol(const char *fullpath, struct TCP_Server_Info *server)
1218 struct vol_info *vi;
1220 if (!fullpath || !server)
1223 cifs_dbg(FYI, "%s: fullpath: %s\n", __func__, fullpath);
1225 spin_lock(&vol_list_lock);
1226 vi = find_vol(fullpath);
1228 spin_unlock(&vol_list_lock);
1231 kref_get(&vi->refcnt);
1232 spin_unlock(&vol_list_lock);
1234 cifs_dbg(FYI, "%s: updating volume info\n", __func__);
1235 spin_lock(&vi->ctx_lock);
1236 memcpy(&vi->ctx.dstaddr, &server->dstaddr,
1237 sizeof(vi->ctx.dstaddr));
1238 spin_unlock(&vi->ctx_lock);
1240 kref_put(&vi->refcnt, vol_release);
1246 * dfs_cache_del_vol - remove volume info in DFS cache during umount()
1248 * @fullpath: fullpath to look up in volume list.
1250 void dfs_cache_del_vol(const char *fullpath)
1252 struct vol_info *vi;
1254 if (!fullpath || !*fullpath)
1257 cifs_dbg(FYI, "%s: fullpath: %s\n", __func__, fullpath);
1259 spin_lock(&vol_list_lock);
1260 vi = find_vol(fullpath);
1261 spin_unlock(&vol_list_lock);
1264 kref_put(&vi->refcnt, vol_release);
1268 * dfs_cache_get_tgt_share - parse a DFS target
1270 * @path: DFS full path
1271 * @it: DFS target iterator.
1272 * @share: tree name.
1273 * @prefix: prefix path.
1275 * Return zero if target was parsed correctly, otherwise non-zero.
1277 int dfs_cache_get_tgt_share(char *path, const struct dfs_cache_tgt_iterator *it,
1278 char **share, char **prefix)
1282 size_t plen1, plen2;
1284 if (!it || !path || !share || !prefix || strlen(path) < it->it_path_consumed)
1290 sep = it->it_name[0];
1291 if (sep != '\\' && sep != '/')
1294 s = strchr(it->it_name + 1, sep);
1298 /* point to prefix in target node */
1299 s = strchrnul(s + 1, sep);
1301 /* extract target share */
1302 *share = kstrndup(it->it_name, s - it->it_name, GFP_KERNEL);
1306 /* skip separator */
1309 /* point to prefix in DFS path */
1310 p = path + it->it_path_consumed;
1314 /* merge prefix paths from DFS path and target node */
1315 plen1 = it->it_name + strlen(it->it_name) - s;
1316 plen2 = path + strlen(path) - p;
1317 if (plen1 || plen2) {
1318 len = plen1 + plen2 + 2;
1319 *prefix = kmalloc(len, GFP_KERNEL);
1326 scnprintf(*prefix, len, "%.*s%c%.*s", (int)plen1, s, sep, (int)plen2, p);
1328 strscpy(*prefix, p, len);
1333 /* Get all tcons that are within a DFS namespace and can be refreshed */
1334 static void get_tcons(struct TCP_Server_Info *server, struct list_head *head)
1336 struct cifs_ses *ses;
1337 struct cifs_tcon *tcon;
1339 INIT_LIST_HEAD(head);
1341 spin_lock(&cifs_tcp_ses_lock);
1342 list_for_each_entry(ses, &server->smb_ses_list, smb_ses_list) {
1343 list_for_each_entry(tcon, &ses->tcon_list, tcon_list) {
1344 if (!tcon->need_reconnect && !tcon->need_reopen_files &&
1347 list_add_tail(&tcon->ulist, head);
1350 if (ses->tcon_ipc && !ses->tcon_ipc->need_reconnect &&
1351 ses->tcon_ipc->dfs_path) {
1352 list_add_tail(&ses->tcon_ipc->ulist, head);
1355 spin_unlock(&cifs_tcp_ses_lock);
1358 static bool is_dfs_link(const char *path)
1362 s = strchr(path + 1, '\\');
1365 return !!strchr(s + 1, '\\');
1368 static char *get_dfs_root(const char *path)
1372 s = strchr(path + 1, '\\');
1374 return ERR_PTR(-EINVAL);
1376 s = strchr(s + 1, '\\');
1378 return ERR_PTR(-EINVAL);
1380 npath = kstrndup(path, s - path, GFP_KERNEL);
1382 return ERR_PTR(-ENOMEM);
1387 static inline void put_tcp_server(struct TCP_Server_Info *server)
1389 cifs_put_tcp_session(server, 0);
1392 static struct TCP_Server_Info *get_tcp_server(struct smb3_fs_context *ctx)
1394 struct TCP_Server_Info *server;
1396 server = cifs_find_tcp_session(ctx);
1397 if (IS_ERR_OR_NULL(server))
1400 spin_lock(&GlobalMid_Lock);
1401 if (server->tcpStatus != CifsGood) {
1402 spin_unlock(&GlobalMid_Lock);
1403 put_tcp_server(server);
1406 spin_unlock(&GlobalMid_Lock);
1411 /* Find root SMB session out of a DFS link path */
1412 static struct cifs_ses *find_root_ses(struct vol_info *vi,
1413 struct cifs_tcon *tcon,
1418 struct cache_entry *ce;
1419 struct dfs_info3_param ref = {0};
1420 char *mdata = NULL, *devname = NULL;
1421 struct TCP_Server_Info *server;
1422 struct cifs_ses *ses;
1423 struct smb3_fs_context ctx = {NULL};
1425 rpath = get_dfs_root(path);
1427 return ERR_CAST(rpath);
1429 down_read(&htable_rw_lock);
1431 ce = lookup_cache_entry(rpath, NULL);
1433 up_read(&htable_rw_lock);
1438 rc = setup_referral(path, ce, &ref, get_tgt_name(ce));
1440 up_read(&htable_rw_lock);
1445 up_read(&htable_rw_lock);
1447 mdata = cifs_compose_mount_options(vi->mntdata, rpath, &ref,
1449 free_dfs_info_param(&ref);
1451 if (IS_ERR(mdata)) {
1452 ses = ERR_CAST(mdata);
1457 rc = cifs_setup_volume_info(&ctx, NULL, devname);
1464 server = get_tcp_server(&ctx);
1466 ses = ERR_PTR(-EHOSTDOWN);
1470 ses = cifs_get_smb_ses(server, &ctx);
1473 smb3_cleanup_fs_context_contents(&ctx);
1481 /* Refresh DFS cache entry from a given tcon */
1482 static int refresh_tcon(struct vol_info *vi, struct cifs_tcon *tcon)
1487 struct cache_entry *ce;
1488 struct cifs_ses *root_ses = NULL, *ses;
1489 struct dfs_info3_param *refs = NULL;
1494 path = tcon->dfs_path + 1;
1496 rc = get_normalized_path(path, &npath);
1500 down_read(&htable_rw_lock);
1502 ce = lookup_cache_entry(npath, NULL);
1505 up_read(&htable_rw_lock);
1509 if (!cache_entry_expired(ce)) {
1510 up_read(&htable_rw_lock);
1514 up_read(&htable_rw_lock);
1516 /* If it's a DFS Link, then use root SMB session for refreshing it */
1517 if (is_dfs_link(npath)) {
1518 ses = root_ses = find_root_ses(vi, tcon, npath);
1528 rc = get_dfs_referral(xid, ses, cache_nlsc, tcon->remap, npath, &refs,
1531 dump_refs(refs, numrefs);
1532 rc = update_cache_entry(npath, refs, numrefs);
1533 free_dfs_info_array(refs, numrefs);
1537 cifs_put_smb_ses(root_ses);
1540 free_normalized_path(path, npath);
1548 * Worker that will refresh DFS cache based on lowest TTL value from a DFS
1551 static void refresh_cache_worker(struct work_struct *work)
1553 struct vol_info *vi, *nvi;
1554 struct TCP_Server_Info *server;
1557 struct cifs_tcon *tcon, *ntcon;
1561 * Find SMB volumes that are eligible (server->tcpStatus == CifsGood)
1564 spin_lock(&vol_list_lock);
1565 list_for_each_entry(vi, &vol_list, list) {
1566 server = get_tcp_server(&vi->ctx);
1570 kref_get(&vi->refcnt);
1571 list_add_tail(&vi->rlist, &vols);
1572 put_tcp_server(server);
1574 spin_unlock(&vol_list_lock);
1576 /* Walk through all TCONs and refresh any expired cache entry */
1577 list_for_each_entry_safe(vi, nvi, &vols, rlist) {
1578 spin_lock(&vi->ctx_lock);
1579 server = get_tcp_server(&vi->ctx);
1580 spin_unlock(&vi->ctx_lock);
1585 get_tcons(server, &tcons);
1588 list_for_each_entry_safe(tcon, ntcon, &tcons, ulist) {
1590 * Skip tcp server if any of its tcons failed to refresh
1591 * (possibily due to reconnects).
1594 rc = refresh_tcon(vi, tcon);
1596 list_del_init(&tcon->ulist);
1597 cifs_put_tcon(tcon);
1600 put_tcp_server(server);
1603 list_del_init(&vi->rlist);
1604 kref_put(&vi->refcnt, vol_release);
1607 spin_lock(&cache_ttl_lock);
1608 queue_delayed_work(dfscache_wq, &refresh_task, cache_ttl * HZ);
1609 spin_unlock(&cache_ttl_lock);