// SPDX-License-Identifier: GPL-2.0 /* * DFS referral cache routines * * Copyright (c) 2018-2019 Paulo Alcantara */ #include #include #include #include #include #include #include "cifsglob.h" #include "smb2pdu.h" #include "smb2proto.h" #include "cifsproto.h" #include "cifs_debug.h" #include "cifs_unicode.h" #include "smb2glob.h" #include "fs_context.h" #include "dfs_cache.h" #define CACHE_HTABLE_SIZE 32 #define CACHE_MAX_ENTRIES 64 #define IS_INTERLINK_SET(v) ((v) & (DFSREF_REFERRAL_SERVER | \ DFSREF_STORAGE_SERVER)) struct cache_dfs_tgt { char *name; int path_consumed; struct list_head list; }; struct cache_entry { struct hlist_node hlist; const char *path; int ttl; int srvtype; int flags; struct timespec64 etime; int path_consumed; int numtgts; struct list_head tlist; struct cache_dfs_tgt *tgthint; }; struct vol_info { char *fullpath; spinlock_t ctx_lock; struct smb3_fs_context ctx; char *mntdata; struct list_head list; struct list_head rlist; struct kref refcnt; }; static struct kmem_cache *cache_slab __read_mostly; static struct workqueue_struct *dfscache_wq __read_mostly; static int cache_ttl; static DEFINE_SPINLOCK(cache_ttl_lock); static struct nls_table *cache_nlsc; /* * Number of entries in the cache */ static atomic_t cache_count; static struct hlist_head cache_htable[CACHE_HTABLE_SIZE]; static DECLARE_RWSEM(htable_rw_lock); static LIST_HEAD(vol_list); static DEFINE_SPINLOCK(vol_list_lock); static void refresh_cache_worker(struct work_struct *work); static DECLARE_DELAYED_WORK(refresh_task, refresh_cache_worker); static int get_normalized_path(const char *path, char **npath) { if (!path || strlen(path) < 3 || (*path != '\\' && *path != '/')) return -EINVAL; if (*path == '\\') { *npath = (char *)path; } else { *npath = kstrndup(path, strlen(path), GFP_KERNEL); if (!*npath) return -ENOMEM; convert_delimiter(*npath, '\\'); } return 0; } static inline void free_normalized_path(const char *path, char *npath) { if (path != npath) kfree(npath); } static inline bool cache_entry_expired(const struct cache_entry *ce) { struct timespec64 ts; ktime_get_coarse_real_ts64(&ts); return timespec64_compare(&ts, &ce->etime) >= 0; } static inline void free_tgts(struct cache_entry *ce) { struct cache_dfs_tgt *t, *n; list_for_each_entry_safe(t, n, &ce->tlist, list) { list_del(&t->list); kfree(t->name); kfree(t); } } static inline void flush_cache_ent(struct cache_entry *ce) { hlist_del_init(&ce->hlist); kfree(ce->path); free_tgts(ce); atomic_dec(&cache_count); kmem_cache_free(cache_slab, ce); } static void flush_cache_ents(void) { int i; for (i = 0; i < CACHE_HTABLE_SIZE; i++) { struct hlist_head *l = &cache_htable[i]; struct hlist_node *n; struct cache_entry *ce; hlist_for_each_entry_safe(ce, n, l, hlist) { if (!hlist_unhashed(&ce->hlist)) flush_cache_ent(ce); } } } /* * dfs cache /proc file */ static int dfscache_proc_show(struct seq_file *m, void *v) { int i; struct cache_entry *ce; struct cache_dfs_tgt *t; seq_puts(m, "DFS cache\n---------\n"); down_read(&htable_rw_lock); for (i = 0; i < CACHE_HTABLE_SIZE; i++) { struct hlist_head *l = &cache_htable[i]; hlist_for_each_entry(ce, l, hlist) { if (hlist_unhashed(&ce->hlist)) continue; seq_printf(m, "cache entry: path=%s,type=%s,ttl=%d,etime=%ld," "interlink=%s,path_consumed=%d,expired=%s\n", ce->path, ce->srvtype == DFS_TYPE_ROOT ? "root" : "link", ce->ttl, ce->etime.tv_nsec, IS_INTERLINK_SET(ce->flags) ? "yes" : "no", ce->path_consumed, cache_entry_expired(ce) ? "yes" : "no"); list_for_each_entry(t, &ce->tlist, list) { seq_printf(m, " %s%s\n", t->name, ce->tgthint == t ? " (target hint)" : ""); } } } up_read(&htable_rw_lock); return 0; } static ssize_t dfscache_proc_write(struct file *file, const char __user *buffer, size_t count, loff_t *ppos) { char c; int rc; rc = get_user(c, buffer); if (rc) return rc; if (c != '0') return -EINVAL; cifs_dbg(FYI, "clearing dfs cache\n"); down_write(&htable_rw_lock); flush_cache_ents(); up_write(&htable_rw_lock); return count; } static int dfscache_proc_open(struct inode *inode, struct file *file) { return single_open(file, dfscache_proc_show, NULL); } const struct proc_ops dfscache_proc_ops = { .proc_open = dfscache_proc_open, .proc_read = seq_read, .proc_lseek = seq_lseek, .proc_release = single_release, .proc_write = dfscache_proc_write, }; #ifdef CONFIG_CIFS_DEBUG2 static inline void dump_tgts(const struct cache_entry *ce) { struct cache_dfs_tgt *t; cifs_dbg(FYI, "target list:\n"); list_for_each_entry(t, &ce->tlist, list) { cifs_dbg(FYI, " %s%s\n", t->name, ce->tgthint == t ? " (target hint)" : ""); } } static inline void dump_ce(const struct cache_entry *ce) { cifs_dbg(FYI, "cache entry: path=%s,type=%s,ttl=%d,etime=%ld,interlink=%s,path_consumed=%d,expired=%s\n", ce->path, ce->srvtype == DFS_TYPE_ROOT ? "root" : "link", ce->ttl, ce->etime.tv_nsec, IS_INTERLINK_SET(ce->flags) ? "yes" : "no", ce->path_consumed, cache_entry_expired(ce) ? "yes" : "no"); dump_tgts(ce); } static inline void dump_refs(const struct dfs_info3_param *refs, int numrefs) { int i; cifs_dbg(FYI, "DFS referrals returned by the server:\n"); for (i = 0; i < numrefs; i++) { const struct dfs_info3_param *ref = &refs[i]; cifs_dbg(FYI, "\n" "flags: 0x%x\n" "path_consumed: %d\n" "server_type: 0x%x\n" "ref_flag: 0x%x\n" "path_name: %s\n" "node_name: %s\n" "ttl: %d (%dm)\n", ref->flags, ref->path_consumed, ref->server_type, ref->ref_flag, ref->path_name, ref->node_name, ref->ttl, ref->ttl / 60); } } #else #define dump_tgts(e) #define dump_ce(e) #define dump_refs(r, n) #endif /** * dfs_cache_init - Initialize DFS referral cache. * * Return zero if initialized successfully, otherwise non-zero. */ int dfs_cache_init(void) { int rc; int i; dfscache_wq = alloc_workqueue("cifs-dfscache", WQ_FREEZABLE | WQ_MEM_RECLAIM, 1); if (!dfscache_wq) return -ENOMEM; cache_slab = kmem_cache_create("cifs_dfs_cache", sizeof(struct cache_entry), 0, SLAB_HWCACHE_ALIGN, NULL); if (!cache_slab) { rc = -ENOMEM; goto out_destroy_wq; } for (i = 0; i < CACHE_HTABLE_SIZE; i++) INIT_HLIST_HEAD(&cache_htable[i]); atomic_set(&cache_count, 0); cache_nlsc = load_nls_default(); cifs_dbg(FYI, "%s: initialized DFS referral cache\n", __func__); return 0; out_destroy_wq: destroy_workqueue(dfscache_wq); return rc; } static inline unsigned int cache_entry_hash(const void *data, int size) { unsigned int h; h = jhash(data, size, 0); return h & (CACHE_HTABLE_SIZE - 1); } /* Check whether second path component of @path is SYSVOL or NETLOGON */ static inline bool is_sysvol_or_netlogon(const char *path) { const char *s; char sep = path[0]; s = strchr(path + 1, sep) + 1; return !strncasecmp(s, "sysvol", strlen("sysvol")) || !strncasecmp(s, "netlogon", strlen("netlogon")); } /* Return target hint of a DFS cache entry */ static inline char *get_tgt_name(const struct cache_entry *ce) { struct cache_dfs_tgt *t = ce->tgthint; return t ? t->name : ERR_PTR(-ENOENT); } /* Return expire time out of a new entry's TTL */ static inline struct timespec64 get_expire_time(int ttl) { struct timespec64 ts = { .tv_sec = ttl, .tv_nsec = 0, }; struct timespec64 now; ktime_get_coarse_real_ts64(&now); return timespec64_add(now, ts); } /* Allocate a new DFS target */ static struct cache_dfs_tgt *alloc_target(const char *name, int path_consumed) { struct cache_dfs_tgt *t; t = kmalloc(sizeof(*t), GFP_ATOMIC); if (!t) return ERR_PTR(-ENOMEM); t->name = kstrndup(name, strlen(name), GFP_ATOMIC); if (!t->name) { kfree(t); return ERR_PTR(-ENOMEM); } t->path_consumed = path_consumed; INIT_LIST_HEAD(&t->list); return t; } /* * Copy DFS referral information to a cache entry and conditionally update * target hint. */ static int copy_ref_data(const struct dfs_info3_param *refs, int numrefs, struct cache_entry *ce, const char *tgthint) { int i; ce->ttl = refs[0].ttl; ce->etime = get_expire_time(ce->ttl); ce->srvtype = refs[0].server_type; ce->flags = refs[0].ref_flag; ce->path_consumed = refs[0].path_consumed; for (i = 0; i < numrefs; i++) { struct cache_dfs_tgt *t; t = alloc_target(refs[i].node_name, refs[i].path_consumed); if (IS_ERR(t)) { free_tgts(ce); return PTR_ERR(t); } if (tgthint && !strcasecmp(t->name, tgthint)) { list_add(&t->list, &ce->tlist); tgthint = NULL; } else { list_add_tail(&t->list, &ce->tlist); } ce->numtgts++; } ce->tgthint = list_first_entry_or_null(&ce->tlist, struct cache_dfs_tgt, list); return 0; } /* Allocate a new cache entry */ static struct cache_entry *alloc_cache_entry(const char *path, const struct dfs_info3_param *refs, int numrefs) { struct cache_entry *ce; int rc; ce = kmem_cache_zalloc(cache_slab, GFP_KERNEL); if (!ce) return ERR_PTR(-ENOMEM); ce->path = kstrndup(path, strlen(path), GFP_KERNEL); if (!ce->path) { kmem_cache_free(cache_slab, ce); return ERR_PTR(-ENOMEM); } INIT_HLIST_NODE(&ce->hlist); INIT_LIST_HEAD(&ce->tlist); rc = copy_ref_data(refs, numrefs, ce, NULL); if (rc) { kfree(ce->path); kmem_cache_free(cache_slab, ce); ce = ERR_PTR(rc); } return ce; } /* Must be called with htable_rw_lock held */ static void remove_oldest_entry(void) { int i; struct cache_entry *ce; struct cache_entry *to_del = NULL; for (i = 0; i < CACHE_HTABLE_SIZE; i++) { struct hlist_head *l = &cache_htable[i]; hlist_for_each_entry(ce, l, hlist) { if (hlist_unhashed(&ce->hlist)) continue; if (!to_del || timespec64_compare(&ce->etime, &to_del->etime) < 0) to_del = ce; } } if (!to_del) { cifs_dbg(FYI, "%s: no entry to remove\n", __func__); return; } cifs_dbg(FYI, "%s: removing entry\n", __func__); dump_ce(to_del); flush_cache_ent(to_del); } /* Add a new DFS cache entry */ static int add_cache_entry(const char *path, unsigned int hash, struct dfs_info3_param *refs, int numrefs) { struct cache_entry *ce; ce = alloc_cache_entry(path, refs, numrefs); if (IS_ERR(ce)) return PTR_ERR(ce); spin_lock(&cache_ttl_lock); if (!cache_ttl) { cache_ttl = ce->ttl; queue_delayed_work(dfscache_wq, &refresh_task, cache_ttl * HZ); } else { cache_ttl = min_t(int, cache_ttl, ce->ttl); mod_delayed_work(dfscache_wq, &refresh_task, cache_ttl * HZ); } spin_unlock(&cache_ttl_lock); down_write(&htable_rw_lock); hlist_add_head(&ce->hlist, &cache_htable[hash]); dump_ce(ce); up_write(&htable_rw_lock); return 0; } static struct cache_entry *__lookup_cache_entry(const char *path) { struct cache_entry *ce; unsigned int h; bool found = false; h = cache_entry_hash(path, strlen(path)); hlist_for_each_entry(ce, &cache_htable[h], hlist) { if (!strcasecmp(path, ce->path)) { found = true; dump_ce(ce); break; } } if (!found) ce = ERR_PTR(-ENOENT); return ce; } /* * Find a DFS cache entry in hash table and optionally check prefix path against * @path. * Use whole path components in the match. * Must be called with htable_rw_lock held. * * Return ERR_PTR(-ENOENT) if the entry is not found. */ static struct cache_entry *lookup_cache_entry(const char *path, unsigned int *hash) { struct cache_entry *ce = ERR_PTR(-ENOENT); unsigned int h; int cnt = 0; char *npath; char *s, *e; char sep; npath = kstrndup(path, strlen(path), GFP_KERNEL); if (!npath) return ERR_PTR(-ENOMEM); s = npath; sep = *npath; while ((s = strchr(s, sep)) && ++cnt < 3) s++; if (cnt < 3) { h = cache_entry_hash(path, strlen(path)); ce = __lookup_cache_entry(path); goto out; } /* * Handle paths that have more than two path components and are a complete prefix of the DFS * referral request path (@path). * * See MS-DFSC 3.2.5.5 "Receiving a Root Referral Request or Link Referral Request". */ h = cache_entry_hash(npath, strlen(npath)); e = npath + strlen(npath) - 1; while (e > s) { char tmp; /* skip separators */ while (e > s && *e == sep) e--; if (e == s) goto out; tmp = *(e+1); *(e+1) = 0; ce = __lookup_cache_entry(npath); if (!IS_ERR(ce)) { h = cache_entry_hash(npath, strlen(npath)); break; } *(e+1) = tmp; /* backward until separator */ while (e > s && *e != sep) e--; } out: if (hash) *hash = h; kfree(npath); return ce; } static void __vol_release(struct vol_info *vi) { kfree(vi->fullpath); kfree(vi->mntdata); cifs_cleanup_volume_info_contents(&vi->ctx); kfree(vi); } static void vol_release(struct kref *kref) { struct vol_info *vi = container_of(kref, struct vol_info, refcnt); spin_lock(&vol_list_lock); list_del(&vi->list); spin_unlock(&vol_list_lock); __vol_release(vi); } static inline void free_vol_list(void) { struct vol_info *vi, *nvi; list_for_each_entry_safe(vi, nvi, &vol_list, list) { list_del_init(&vi->list); __vol_release(vi); } } /** * dfs_cache_destroy - destroy DFS referral cache */ void dfs_cache_destroy(void) { cancel_delayed_work_sync(&refresh_task); unload_nls(cache_nlsc); free_vol_list(); flush_cache_ents(); kmem_cache_destroy(cache_slab); destroy_workqueue(dfscache_wq); cifs_dbg(FYI, "%s: destroyed DFS referral cache\n", __func__); } /* Must be called with htable_rw_lock held */ static int __update_cache_entry(const char *path, const struct dfs_info3_param *refs, int numrefs) { int rc; struct cache_entry *ce; char *s, *th = NULL; ce = lookup_cache_entry(path, NULL); if (IS_ERR(ce)) return PTR_ERR(ce); if (ce->tgthint) { s = ce->tgthint->name; th = kstrndup(s, strlen(s), GFP_ATOMIC); if (!th) return -ENOMEM; } free_tgts(ce); ce->numtgts = 0; rc = copy_ref_data(refs, numrefs, ce, th); kfree(th); return rc; } static int get_dfs_referral(const unsigned int xid, struct cifs_ses *ses, const struct nls_table *nls_codepage, int remap, const char *path, struct dfs_info3_param **refs, int *numrefs) { cifs_dbg(FYI, "%s: get an DFS referral for %s\n", __func__, path); if (!ses || !ses->server || !ses->server->ops->get_dfs_refer) return -EOPNOTSUPP; if (unlikely(!nls_codepage)) return -EINVAL; *refs = NULL; *numrefs = 0; return ses->server->ops->get_dfs_refer(xid, ses, path, refs, numrefs, nls_codepage, remap); } /* Update an expired cache entry by getting a new DFS referral from server */ static int update_cache_entry(const char *path, const struct dfs_info3_param *refs, int numrefs) { int rc; down_write(&htable_rw_lock); rc = __update_cache_entry(path, refs, numrefs); up_write(&htable_rw_lock); return rc; } /* * Find, create or update a DFS cache entry. * * If the entry wasn't found, it will create a new one. Or if it was found but * expired, then it will update the entry accordingly. * * For interlinks, __cifs_dfs_mount() and expand_dfs_referral() are supposed to * handle them properly. */ static int __dfs_cache_find(const unsigned int xid, struct cifs_ses *ses, const struct nls_table *nls_codepage, int remap, const char *path, bool noreq) { int rc; unsigned int hash; struct cache_entry *ce; struct dfs_info3_param *refs = NULL; int numrefs = 0; bool newent = false; cifs_dbg(FYI, "%s: search path: %s\n", __func__, path); down_read(&htable_rw_lock); ce = lookup_cache_entry(path, &hash); /* * If @noreq is set, no requests will be sent to the server. Just return * the cache entry. */ if (noreq) { up_read(&htable_rw_lock); return PTR_ERR_OR_ZERO(ce); } if (!IS_ERR(ce)) { if (!cache_entry_expired(ce)) { dump_ce(ce); up_read(&htable_rw_lock); return 0; } } else { newent = true; } up_read(&htable_rw_lock); /* * No entry was found. * * Request a new DFS referral in order to create a new cache entry, or * updating an existing one. */ rc = get_dfs_referral(xid, ses, nls_codepage, remap, path, &refs, &numrefs); if (rc) return rc; dump_refs(refs, numrefs); if (!newent) { rc = update_cache_entry(path, refs, numrefs); goto out_free_refs; } if (atomic_read(&cache_count) >= CACHE_MAX_ENTRIES) { cifs_dbg(FYI, "%s: reached max cache size (%d)\n", __func__, CACHE_MAX_ENTRIES); down_write(&htable_rw_lock); remove_oldest_entry(); up_write(&htable_rw_lock); } rc = add_cache_entry(path, hash, refs, numrefs); if (!rc) atomic_inc(&cache_count); out_free_refs: free_dfs_info_array(refs, numrefs); return rc; } /* * Set up a DFS referral from a given cache entry. * * Must be called with htable_rw_lock held. */ static int setup_referral(const char *path, struct cache_entry *ce, struct dfs_info3_param *ref, const char *target) { int rc; cifs_dbg(FYI, "%s: set up new ref\n", __func__); memset(ref, 0, sizeof(*ref)); ref->path_name = kstrndup(path, strlen(path), GFP_ATOMIC); if (!ref->path_name) return -ENOMEM; ref->node_name = kstrndup(target, strlen(target), GFP_ATOMIC); if (!ref->node_name) { rc = -ENOMEM; goto err_free_path; } ref->path_consumed = ce->path_consumed; ref->ttl = ce->ttl; ref->server_type = ce->srvtype; ref->ref_flag = ce->flags; return 0; err_free_path: kfree(ref->path_name); ref->path_name = NULL; return rc; } /* Return target list of a DFS cache entry */ static int get_targets(struct cache_entry *ce, struct dfs_cache_tgt_list *tl) { int rc; struct list_head *head = &tl->tl_list; struct cache_dfs_tgt *t; struct dfs_cache_tgt_iterator *it, *nit; memset(tl, 0, sizeof(*tl)); INIT_LIST_HEAD(head); list_for_each_entry(t, &ce->tlist, list) { it = kzalloc(sizeof(*it), GFP_ATOMIC); if (!it) { rc = -ENOMEM; goto err_free_it; } it->it_name = kstrndup(t->name, strlen(t->name), GFP_ATOMIC); if (!it->it_name) { kfree(it); rc = -ENOMEM; goto err_free_it; } it->it_path_consumed = t->path_consumed; if (ce->tgthint == t) list_add(&it->it_list, head); else list_add_tail(&it->it_list, head); } tl->tl_numtgts = ce->numtgts; return 0; err_free_it: list_for_each_entry_safe(it, nit, head, it_list) { kfree(it->it_name); kfree(it); } return rc; } /** * dfs_cache_find - find a DFS cache entry * * If it doesn't find the cache entry, then it will get a DFS referral * for @path and create a new entry. * * In case the cache entry exists but expired, it will get a DFS referral * for @path and then update the respective cache entry. * * These parameters are passed down to the get_dfs_refer() call if it * needs to be issued: * @xid: syscall xid * @ses: smb session to issue the request on * @nls_codepage: charset conversion * @remap: path character remapping type * @path: path to lookup in DFS referral cache. * * @ref: when non-NULL, store single DFS referral result in it. * @tgt_list: when non-NULL, store complete DFS target list in it. * * Return zero if the target was found, otherwise non-zero. */ int dfs_cache_find(const unsigned int xid, struct cifs_ses *ses, const struct nls_table *nls_codepage, int remap, const char *path, struct dfs_info3_param *ref, struct dfs_cache_tgt_list *tgt_list) { int rc; char *npath; struct cache_entry *ce; rc = get_normalized_path(path, &npath); if (rc) return rc; rc = __dfs_cache_find(xid, ses, nls_codepage, remap, npath, false); if (rc) goto out_free_path; down_read(&htable_rw_lock); ce = lookup_cache_entry(npath, NULL); if (IS_ERR(ce)) { up_read(&htable_rw_lock); rc = PTR_ERR(ce); goto out_free_path; } if (ref) rc = setup_referral(path, ce, ref, get_tgt_name(ce)); else rc = 0; if (!rc && tgt_list) rc = get_targets(ce, tgt_list); up_read(&htable_rw_lock); out_free_path: free_normalized_path(path, npath); return rc; } /** * dfs_cache_noreq_find - find a DFS cache entry without sending any requests to * the currently connected server. * * NOTE: This function will neither update a cache entry in case it was * expired, nor create a new cache entry if @path hasn't been found. It heavily * relies on an existing cache entry. * * @path: path to lookup in the DFS referral cache. * @ref: when non-NULL, store single DFS referral result in it. * @tgt_list: when non-NULL, store complete DFS target list in it. * * Return 0 if successful. * Return -ENOENT if the entry was not found. * Return non-zero for other errors. */ int dfs_cache_noreq_find(const char *path, struct dfs_info3_param *ref, struct dfs_cache_tgt_list *tgt_list) { int rc; char *npath; struct cache_entry *ce; rc = get_normalized_path(path, &npath); if (rc) return rc; cifs_dbg(FYI, "%s: path: %s\n", __func__, npath); down_read(&htable_rw_lock); ce = lookup_cache_entry(npath, NULL); if (IS_ERR(ce)) { rc = PTR_ERR(ce); goto out_unlock; } if (ref) rc = setup_referral(path, ce, ref, get_tgt_name(ce)); else rc = 0; if (!rc && tgt_list) rc = get_targets(ce, tgt_list); out_unlock: up_read(&htable_rw_lock); free_normalized_path(path, npath); return rc; } /** * dfs_cache_update_tgthint - update target hint of a DFS cache entry * * If it doesn't find the cache entry, then it will get a DFS referral for @path * and create a new entry. * * In case the cache entry exists but expired, it will get a DFS referral * for @path and then update the respective cache entry. * * @xid: syscall id * @ses: smb session * @nls_codepage: charset conversion * @remap: type of character remapping for paths * @path: path to lookup in DFS referral cache. * @it: DFS target iterator * * Return zero if the target hint was updated successfully, otherwise non-zero. */ int dfs_cache_update_tgthint(const unsigned int xid, struct cifs_ses *ses, const struct nls_table *nls_codepage, int remap, const char *path, const struct dfs_cache_tgt_iterator *it) { int rc; char *npath; struct cache_entry *ce; struct cache_dfs_tgt *t; rc = get_normalized_path(path, &npath); if (rc) return rc; cifs_dbg(FYI, "%s: update target hint - path: %s\n", __func__, npath); rc = __dfs_cache_find(xid, ses, nls_codepage, remap, npath, false); if (rc) goto out_free_path; down_write(&htable_rw_lock); ce = lookup_cache_entry(npath, NULL); if (IS_ERR(ce)) { rc = PTR_ERR(ce); goto out_unlock; } t = ce->tgthint; if (likely(!strcasecmp(it->it_name, t->name))) goto out_unlock; list_for_each_entry(t, &ce->tlist, list) { if (!strcasecmp(t->name, it->it_name)) { ce->tgthint = t; cifs_dbg(FYI, "%s: new target hint: %s\n", __func__, it->it_name); break; } } out_unlock: up_write(&htable_rw_lock); out_free_path: free_normalized_path(path, npath); return rc; } /** * dfs_cache_noreq_update_tgthint - update target hint of a DFS cache entry * without sending any requests to the currently connected server. * * NOTE: This function will neither update a cache entry in case it was * expired, nor create a new cache entry if @path hasn't been found. It heavily * relies on an existing cache entry. * * @path: path to lookup in DFS referral cache. * @it: target iterator which contains the target hint to update the cache * entry with. * * Return zero if the target hint was updated successfully, otherwise non-zero. */ int dfs_cache_noreq_update_tgthint(const char *path, const struct dfs_cache_tgt_iterator *it) { int rc; char *npath; struct cache_entry *ce; struct cache_dfs_tgt *t; if (!it) return -EINVAL; rc = get_normalized_path(path, &npath); if (rc) return rc; cifs_dbg(FYI, "%s: path: %s\n", __func__, npath); down_write(&htable_rw_lock); ce = lookup_cache_entry(npath, NULL); if (IS_ERR(ce)) { rc = PTR_ERR(ce); goto out_unlock; } rc = 0; t = ce->tgthint; if (unlikely(!strcasecmp(it->it_name, t->name))) goto out_unlock; list_for_each_entry(t, &ce->tlist, list) { if (!strcasecmp(t->name, it->it_name)) { ce->tgthint = t; cifs_dbg(FYI, "%s: new target hint: %s\n", __func__, it->it_name); break; } } out_unlock: up_write(&htable_rw_lock); free_normalized_path(path, npath); return rc; } /** * dfs_cache_get_tgt_referral - returns a DFS referral (@ref) from a given * target iterator (@it). * * @path: path to lookup in DFS referral cache. * @it: DFS target iterator. * @ref: DFS referral pointer to set up the gathered information. * * Return zero if the DFS referral was set up correctly, otherwise non-zero. */ int dfs_cache_get_tgt_referral(const char *path, const struct dfs_cache_tgt_iterator *it, struct dfs_info3_param *ref) { int rc; char *npath; struct cache_entry *ce; if (!it || !ref) return -EINVAL; rc = get_normalized_path(path, &npath); if (rc) return rc; cifs_dbg(FYI, "%s: path: %s\n", __func__, npath); down_read(&htable_rw_lock); ce = lookup_cache_entry(npath, NULL); if (IS_ERR(ce)) { rc = PTR_ERR(ce); goto out_unlock; } cifs_dbg(FYI, "%s: target name: %s\n", __func__, it->it_name); rc = setup_referral(path, ce, ref, it->it_name); out_unlock: up_read(&htable_rw_lock); free_normalized_path(path, npath); return rc; } /** * dfs_cache_add_vol - add a cifs context during mount() that will be handled by * DFS cache refresh worker. * * @mntdata: mount data. * @ctx: cifs context. * @fullpath: origin full path. * * Return zero if context was set up correctly, otherwise non-zero. */ int dfs_cache_add_vol(char *mntdata, struct smb3_fs_context *ctx, const char *fullpath) { int rc; struct vol_info *vi; if (!ctx || !fullpath || !mntdata) return -EINVAL; cifs_dbg(FYI, "%s: fullpath: %s\n", __func__, fullpath); vi = kzalloc(sizeof(*vi), GFP_KERNEL); if (!vi) return -ENOMEM; vi->fullpath = kstrndup(fullpath, strlen(fullpath), GFP_KERNEL); if (!vi->fullpath) { rc = -ENOMEM; goto err_free_vi; } rc = smb3_fs_context_dup(&vi->ctx, ctx); if (rc) goto err_free_fullpath; vi->mntdata = mntdata; spin_lock_init(&vi->ctx_lock); kref_init(&vi->refcnt); spin_lock(&vol_list_lock); list_add_tail(&vi->list, &vol_list); spin_unlock(&vol_list_lock); return 0; err_free_fullpath: kfree(vi->fullpath); err_free_vi: kfree(vi); return rc; } /* Must be called with vol_list_lock held */ static struct vol_info *find_vol(const char *fullpath) { struct vol_info *vi; list_for_each_entry(vi, &vol_list, list) { cifs_dbg(FYI, "%s: vi->fullpath: %s\n", __func__, vi->fullpath); if (!strcasecmp(vi->fullpath, fullpath)) return vi; } return ERR_PTR(-ENOENT); } /** * dfs_cache_update_vol - update vol info in DFS cache after failover * * @fullpath: fullpath to look up in volume list. * @server: TCP ses pointer. * * Return zero if volume was updated, otherwise non-zero. */ int dfs_cache_update_vol(const char *fullpath, struct TCP_Server_Info *server) { struct vol_info *vi; if (!fullpath || !server) return -EINVAL; cifs_dbg(FYI, "%s: fullpath: %s\n", __func__, fullpath); spin_lock(&vol_list_lock); vi = find_vol(fullpath); if (IS_ERR(vi)) { spin_unlock(&vol_list_lock); return PTR_ERR(vi); } kref_get(&vi->refcnt); spin_unlock(&vol_list_lock); cifs_dbg(FYI, "%s: updating volume info\n", __func__); spin_lock(&vi->ctx_lock); memcpy(&vi->ctx.dstaddr, &server->dstaddr, sizeof(vi->ctx.dstaddr)); spin_unlock(&vi->ctx_lock); kref_put(&vi->refcnt, vol_release); return 0; } /** * dfs_cache_del_vol - remove volume info in DFS cache during umount() * * @fullpath: fullpath to look up in volume list. */ void dfs_cache_del_vol(const char *fullpath) { struct vol_info *vi; if (!fullpath || !*fullpath) return; cifs_dbg(FYI, "%s: fullpath: %s\n", __func__, fullpath); spin_lock(&vol_list_lock); vi = find_vol(fullpath); spin_unlock(&vol_list_lock); kref_put(&vi->refcnt, vol_release); } /** * dfs_cache_get_tgt_share - parse a DFS target * * @path: DFS full path * @it: DFS target iterator. * @share: tree name. * @prefix: prefix path. * * Return zero if target was parsed correctly, otherwise non-zero. */ int dfs_cache_get_tgt_share(char *path, const struct dfs_cache_tgt_iterator *it, char **share, char **prefix) { char *s, sep, *p; size_t len; size_t plen1, plen2; if (!it || !path || !share || !prefix || strlen(path) < it->it_path_consumed) return -EINVAL; *share = NULL; *prefix = NULL; sep = it->it_name[0]; if (sep != '\\' && sep != '/') return -EINVAL; s = strchr(it->it_name + 1, sep); if (!s) return -EINVAL; /* point to prefix in target node */ s = strchrnul(s + 1, sep); /* extract target share */ *share = kstrndup(it->it_name, s - it->it_name, GFP_KERNEL); if (!*share) return -ENOMEM; /* skip separator */ if (*s) s++; /* point to prefix in DFS path */ p = path + it->it_path_consumed; if (*p == sep) p++; /* merge prefix paths from DFS path and target node */ plen1 = it->it_name + strlen(it->it_name) - s; plen2 = path + strlen(path) - p; if (plen1 || plen2) { len = plen1 + plen2 + 2; *prefix = kmalloc(len, GFP_KERNEL); if (!*prefix) { kfree(*share); *share = NULL; return -ENOMEM; } if (plen1) scnprintf(*prefix, len, "%.*s%c%.*s", (int)plen1, s, sep, (int)plen2, p); else strscpy(*prefix, p, len); } return 0; } /* Get all tcons that are within a DFS namespace and can be refreshed */ static void get_tcons(struct TCP_Server_Info *server, struct list_head *head) { struct cifs_ses *ses; struct cifs_tcon *tcon; INIT_LIST_HEAD(head); spin_lock(&cifs_tcp_ses_lock); list_for_each_entry(ses, &server->smb_ses_list, smb_ses_list) { list_for_each_entry(tcon, &ses->tcon_list, tcon_list) { if (!tcon->need_reconnect && !tcon->need_reopen_files && tcon->dfs_path) { tcon->tc_count++; list_add_tail(&tcon->ulist, head); } } if (ses->tcon_ipc && !ses->tcon_ipc->need_reconnect && ses->tcon_ipc->dfs_path) { list_add_tail(&ses->tcon_ipc->ulist, head); } } spin_unlock(&cifs_tcp_ses_lock); } static bool is_dfs_link(const char *path) { char *s; s = strchr(path + 1, '\\'); if (!s) return false; return !!strchr(s + 1, '\\'); } static char *get_dfs_root(const char *path) { char *s, *npath; s = strchr(path + 1, '\\'); if (!s) return ERR_PTR(-EINVAL); s = strchr(s + 1, '\\'); if (!s) return ERR_PTR(-EINVAL); npath = kstrndup(path, s - path, GFP_KERNEL); if (!npath) return ERR_PTR(-ENOMEM); return npath; } static inline void put_tcp_server(struct TCP_Server_Info *server) { cifs_put_tcp_session(server, 0); } static struct TCP_Server_Info *get_tcp_server(struct smb3_fs_context *ctx) { struct TCP_Server_Info *server; server = cifs_find_tcp_session(ctx); if (IS_ERR_OR_NULL(server)) return NULL; spin_lock(&GlobalMid_Lock); if (server->tcpStatus != CifsGood) { spin_unlock(&GlobalMid_Lock); put_tcp_server(server); return NULL; } spin_unlock(&GlobalMid_Lock); return server; } /* Find root SMB session out of a DFS link path */ static struct cifs_ses *find_root_ses(struct vol_info *vi, struct cifs_tcon *tcon, const char *path) { char *rpath; int rc; struct cache_entry *ce; struct dfs_info3_param ref = {0}; char *mdata = NULL; struct TCP_Server_Info *server; struct cifs_ses *ses; struct smb3_fs_context ctx = {NULL}; rpath = get_dfs_root(path); if (IS_ERR(rpath)) return ERR_CAST(rpath); down_read(&htable_rw_lock); ce = lookup_cache_entry(rpath, NULL); if (IS_ERR(ce)) { up_read(&htable_rw_lock); ses = ERR_CAST(ce); goto out; } rc = setup_referral(path, ce, &ref, get_tgt_name(ce)); if (rc) { up_read(&htable_rw_lock); ses = ERR_PTR(rc); goto out; } up_read(&htable_rw_lock); mdata = cifs_compose_mount_options(vi->mntdata, rpath, &ref); free_dfs_info_param(&ref); if (IS_ERR(mdata)) { ses = ERR_CAST(mdata); mdata = NULL; goto out; } rc = cifs_setup_volume_info(&ctx); if (rc) { ses = ERR_PTR(rc); goto out; } server = get_tcp_server(&ctx); if (!server) { ses = ERR_PTR(-EHOSTDOWN); goto out; } ses = cifs_get_smb_ses(server, &ctx); out: cifs_cleanup_volume_info_contents(&ctx); kfree(mdata); kfree(rpath); return ses; } /* Refresh DFS cache entry from a given tcon */ static int refresh_tcon(struct vol_info *vi, struct cifs_tcon *tcon) { int rc = 0; unsigned int xid; char *path, *npath; struct cache_entry *ce; struct cifs_ses *root_ses = NULL, *ses; struct dfs_info3_param *refs = NULL; int numrefs = 0; xid = get_xid(); path = tcon->dfs_path + 1; rc = get_normalized_path(path, &npath); if (rc) goto out_free_xid; down_read(&htable_rw_lock); ce = lookup_cache_entry(npath, NULL); if (IS_ERR(ce)) { rc = PTR_ERR(ce); up_read(&htable_rw_lock); goto out_free_path; } if (!cache_entry_expired(ce)) { up_read(&htable_rw_lock); goto out_free_path; } up_read(&htable_rw_lock); /* If it's a DFS Link, then use root SMB session for refreshing it */ if (is_dfs_link(npath)) { ses = root_ses = find_root_ses(vi, tcon, npath); if (IS_ERR(ses)) { rc = PTR_ERR(ses); root_ses = NULL; goto out_free_path; } } else { ses = tcon->ses; } rc = get_dfs_referral(xid, ses, cache_nlsc, tcon->remap, npath, &refs, &numrefs); if (!rc) { dump_refs(refs, numrefs); rc = update_cache_entry(npath, refs, numrefs); free_dfs_info_array(refs, numrefs); } if (root_ses) cifs_put_smb_ses(root_ses); out_free_path: free_normalized_path(path, npath); out_free_xid: free_xid(xid); return rc; } /* * Worker that will refresh DFS cache based on lowest TTL value from a DFS * referral. */ static void refresh_cache_worker(struct work_struct *work) { struct vol_info *vi, *nvi; struct TCP_Server_Info *server; LIST_HEAD(vols); LIST_HEAD(tcons); struct cifs_tcon *tcon, *ntcon; int rc; /* * Find SMB volumes that are eligible (server->tcpStatus == CifsGood) * for refreshing. */ spin_lock(&vol_list_lock); list_for_each_entry(vi, &vol_list, list) { server = get_tcp_server(&vi->ctx); if (!server) continue; kref_get(&vi->refcnt); list_add_tail(&vi->rlist, &vols); put_tcp_server(server); } spin_unlock(&vol_list_lock); /* Walk through all TCONs and refresh any expired cache entry */ list_for_each_entry_safe(vi, nvi, &vols, rlist) { spin_lock(&vi->ctx_lock); server = get_tcp_server(&vi->ctx); spin_unlock(&vi->ctx_lock); if (!server) goto next_vol; get_tcons(server, &tcons); rc = 0; list_for_each_entry_safe(tcon, ntcon, &tcons, ulist) { /* * Skip tcp server if any of its tcons failed to refresh * (possibily due to reconnects). */ if (!rc) rc = refresh_tcon(vi, tcon); list_del_init(&tcon->ulist); cifs_put_tcon(tcon); } put_tcp_server(server); next_vol: list_del_init(&vi->rlist); kref_put(&vi->refcnt, vol_release); } spin_lock(&cache_ttl_lock); queue_delayed_work(dfscache_wq, &refresh_task, cache_ttl * HZ); spin_unlock(&cache_ttl_lock); }