diff options
Diffstat (limited to 'fs/cifs/dfs_cache.c')
| -rw-r--r-- | fs/cifs/dfs_cache.c | 1661 |
1 files changed, 0 insertions, 1661 deletions
diff --git a/fs/cifs/dfs_cache.c b/fs/cifs/dfs_cache.c deleted file mode 100644 index dd9643751671..000000000000 --- a/fs/cifs/dfs_cache.c +++ /dev/null @@ -1,1661 +0,0 @@ -// SPDX-License-Identifier: GPL-2.0 -/* - * DFS referral cache routines - * - * Copyright (c) 2018-2019 Paulo Alcantara <palcantara@suse.de> - */ - -#include <linux/jhash.h> -#include <linux/ktime.h> -#include <linux/slab.h> -#include <linux/proc_fs.h> -#include <linux/nls.h> -#include <linux/workqueue.h> -#include <linux/uuid.h> -#include "cifsglob.h" -#include "smb2pdu.h" -#include "smb2proto.h" -#include "cifsproto.h" -#include "cifs_debug.h" -#include "cifs_unicode.h" -#include "smb2glob.h" -#include "dns_resolve.h" - -#include "dfs_cache.h" - -#define CACHE_HTABLE_SIZE 32 -#define CACHE_MAX_ENTRIES 64 -#define CACHE_MIN_TTL 120 /* 2 minutes */ - -#define IS_DFS_INTERLINK(v) (((v) & DFSREF_REFERRAL_SERVER) && !((v) & 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 hdr_flags; /* RESP_GET_DFS_REFERRAL.ReferralHeaderFlags */ - int ttl; /* DFS_REREFERRAL_V3.TimeToLive */ - int srvtype; /* DFS_REREFERRAL_V3.ServerType */ - int ref_flags; /* DFS_REREFERRAL_V3.ReferralEntryFlags */ - struct timespec64 etime; - int path_consumed; /* RESP_GET_DFS_REFERRAL.PathConsumed */ - int numtgts; - struct list_head tlist; - struct cache_dfs_tgt *tgthint; -}; - -/* List of referral server sessions per dfs mount */ -struct mount_group { - struct list_head list; - uuid_t id; - struct cifs_ses *sessions[CACHE_MAX_ENTRIES]; - int num_sessions; - spinlock_t lock; - struct list_head refresh_list; - struct kref refcount; -}; - -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_cp; - -/* - * 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(mount_group_list); -static DEFINE_MUTEX(mount_group_list_lock); - -static void refresh_cache_worker(struct work_struct *work); - -static DECLARE_DELAYED_WORK(refresh_task, refresh_cache_worker); - -static void get_ipc_unc(const char *ref_path, char *ipc, size_t ipclen) -{ - const char *host; - size_t len; - - extract_unc_hostname(ref_path, &host, &len); - scnprintf(ipc, ipclen, "\\\\%.*s\\IPC$", (int)len, host); -} - -static struct cifs_ses *find_ipc_from_server_path(struct cifs_ses **ses, const char *path) -{ - char unc[SERVER_NAME_LENGTH + sizeof("//x/IPC$")] = {0}; - - get_ipc_unc(path, unc, sizeof(unc)); - for (; *ses; ses++) { - if (!strcasecmp(unc, (*ses)->tcon_ipc->treeName)) - return *ses; - } - return ERR_PTR(-ENOENT); -} - -static void __mount_group_release(struct mount_group *mg) -{ - int i; - - for (i = 0; i < mg->num_sessions; i++) - cifs_put_smb_ses(mg->sessions[i]); - kfree(mg); -} - -static void mount_group_release(struct kref *kref) -{ - struct mount_group *mg = container_of(kref, struct mount_group, refcount); - - mutex_lock(&mount_group_list_lock); - list_del(&mg->list); - mutex_unlock(&mount_group_list_lock); - __mount_group_release(mg); -} - -static struct mount_group *find_mount_group_locked(const uuid_t *id) -{ - struct mount_group *mg; - - list_for_each_entry(mg, &mount_group_list, list) { - if (uuid_equal(&mg->id, id)) - return mg; - } - return ERR_PTR(-ENOENT); -} - -static struct mount_group *__get_mount_group_locked(const uuid_t *id) -{ - struct mount_group *mg; - - mg = find_mount_group_locked(id); - if (!IS_ERR(mg)) - return mg; - - mg = kmalloc(sizeof(*mg), GFP_KERNEL); - if (!mg) - return ERR_PTR(-ENOMEM); - kref_init(&mg->refcount); - uuid_copy(&mg->id, id); - mg->num_sessions = 0; - spin_lock_init(&mg->lock); - list_add(&mg->list, &mount_group_list); - return mg; -} - -static struct mount_group *get_mount_group(const uuid_t *id) -{ - struct mount_group *mg; - - mutex_lock(&mount_group_list_lock); - mg = __get_mount_group_locked(id); - if (!IS_ERR(mg)) - kref_get(&mg->refcount); - mutex_unlock(&mount_group_list_lock); - - return mg; -} - -static void free_mount_group_list(void) -{ - struct mount_group *mg, *tmp_mg; - - list_for_each_entry_safe(mg, tmp_mg, &mount_group_list, list) { - list_del_init(&mg->list); - __mount_group_release(mg); - } -} - -/** - * dfs_cache_canonical_path - get a canonical DFS path - * - * @path: DFS path - * @cp: codepage - * @remap: mapping type - * - * Return canonical path if success, otherwise error. - */ -char *dfs_cache_canonical_path(const char *path, const struct nls_table *cp, int remap) -{ - char *tmp; - int plen = 0; - char *npath; - - if (!path || strlen(path) < 3 || (*path != '\\' && *path != '/')) - return ERR_PTR(-EINVAL); - - if (unlikely(strcmp(cp->charset, cache_cp->charset))) { - tmp = (char *)cifs_strndup_to_utf16(path, strlen(path), &plen, cp, remap); - if (!tmp) { - cifs_dbg(VFS, "%s: failed to convert path to utf16\n", __func__); - return ERR_PTR(-EINVAL); - } - - npath = cifs_strndup_from_utf16(tmp, plen, true, cache_cp); - kfree(tmp); - - if (!npath) { - cifs_dbg(VFS, "%s: failed to convert path from utf16\n", __func__); - return ERR_PTR(-EINVAL); - } - } else { - npath = kstrdup(path, GFP_KERNEL); - if (!npath) - return ERR_PTR(-ENOMEM); - } - convert_delimiter(npath, '\\'); - return 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,hdr_flags=0x%x,ref_flags=0x%x,interlink=%s,path_consumed=%d,expired=%s\n", - ce->path, ce->srvtype == DFS_TYPE_ROOT ? "root" : "link", - ce->ttl, ce->etime.tv_nsec, ce->hdr_flags, ce->ref_flags, - IS_DFS_INTERLINK(ce->hdr_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,hdr_flags=0x%x,ref_flags=0x%x,interlink=%s,path_consumed=%d,expired=%s\n", - ce->path, - ce->srvtype == DFS_TYPE_ROOT ? "root" : "link", ce->ttl, - ce->etime.tv_nsec, - ce->hdr_flags, ce->ref_flags, - IS_DFS_INTERLINK(ce->hdr_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_UNBOUND, 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_cp = load_nls("utf8"); - if (!cache_cp) - cache_cp = 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 int cache_entry_hash(const void *data, int size, unsigned int *hash) -{ - int i, clen; - const unsigned char *s = data; - wchar_t c; - unsigned int h = 0; - - for (i = 0; i < size; i += clen) { - clen = cache_cp->char2uni(&s[i], size - i, &c); - if (unlikely(clen < 0)) { - cifs_dbg(VFS, "%s: can't convert char\n", __func__); - return clen; - } - c = cifs_toupper(c); - h = jhash(&c, sizeof(c), h); - } - *hash = h % CACHE_HTABLE_SIZE; - return 0; -} - -/* 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 = kstrdup(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 = max_t(int, refs[0].ttl, CACHE_MIN_TTL); - ce->etime = get_expire_time(ce->ttl); - ce->srvtype = refs[0].server_type; - ce->hdr_flags = refs[0].flags; - ce->ref_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(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 = refs[0].path_name; - refs[0].path_name = NULL; - - 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; -} - -static void remove_oldest_entry_locked(void) -{ - int i; - struct cache_entry *ce; - struct cache_entry *to_del = NULL; - - WARN_ON(!rwsem_is_locked(&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; - 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_locked(struct dfs_info3_param *refs, int numrefs) -{ - int rc; - struct cache_entry *ce; - unsigned int hash; - - WARN_ON(!rwsem_is_locked(&htable_rw_lock)); - - if (atomic_read(&cache_count) >= CACHE_MAX_ENTRIES) { - cifs_dbg(FYI, "%s: reached max cache size (%d)\n", __func__, CACHE_MAX_ENTRIES); - remove_oldest_entry_locked(); - } - - rc = cache_entry_hash(refs[0].path_name, strlen(refs[0].path_name), &hash); - if (rc) - return rc; - - ce = alloc_cache_entry(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); - - hlist_add_head(&ce->hlist, &cache_htable[hash]); - dump_ce(ce); - - atomic_inc(&cache_count); - - return 0; -} - -/* Check if two DFS paths are equal. @s1 and @s2 are expected to be in @cache_cp's charset */ -static bool dfs_path_equal(const char *s1, int len1, const char *s2, int len2) -{ - int i, l1, l2; - wchar_t c1, c2; - - if (len1 != len2) - return false; - - for (i = 0; i < len1; i += l1) { - l1 = cache_cp->char2uni(&s1[i], len1 - i, &c1); - l2 = cache_cp->char2uni(&s2[i], len2 - i, &c2); - if (unlikely(l1 < 0 && l2 < 0)) { - if (s1[i] != s2[i]) - return false; - l1 = 1; - continue; - } - if (l1 != l2) - return false; - if (cifs_toupper(c1) != cifs_toupper(c2)) - return false; - } - return true; -} - -static struct cache_entry *__lookup_cache_entry(const char *path, unsigned int hash, int len) -{ - struct cache_entry *ce; - - hlist_for_each_entry(ce, &cache_htable[hash], hlist) { - if (dfs_path_equal(ce->path, strlen(ce->path), path, len)) { - dump_ce(ce); - return ce; - } - } - return ERR_PTR(-EEXIST); -} - -/* - * Find a DFS cache entry in hash table and optionally check prefix path against normalized @path. - * - * Use whole path components in the match. Must be called with htable_rw_lock held. - * - * Return ERR_PTR(-EEXIST) if the entry is not found. - */ -static struct cache_entry *lookup_cache_entry(const char *path) -{ - struct cache_entry *ce; - int cnt = 0; - const char *s = path, *e; - char sep = *s; - unsigned int hash; - int rc; - - while ((s = strchr(s, sep)) && ++cnt < 3) - s++; - - if (cnt < 3) { - rc = cache_entry_hash(path, strlen(path), &hash); - if (rc) - return ERR_PTR(rc); - return __lookup_cache_entry(path, hash, strlen(path)); - } - /* - * 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". - */ - e = path + strlen(path) - 1; - while (e > s) { - int len; - - /* skip separators */ - while (e > s && *e == sep) - e--; - if (e == s) - break; - - len = e + 1 - path; - rc = cache_entry_hash(path, len, &hash); - if (rc) - return ERR_PTR(rc); - ce = __lookup_cache_entry(path, hash, len); - if (!IS_ERR(ce)) - return ce; - - /* backward until separator */ - while (e > s && *e != sep) - e--; - } - return ERR_PTR(-EEXIST); -} - -/** - * dfs_cache_destroy - destroy DFS referral cache - */ -void dfs_cache_destroy(void) -{ - cancel_delayed_work_sync(&refresh_task); - unload_nls(cache_cp); - free_mount_group_list(); - flush_cache_ents(); - kmem_cache_destroy(cache_slab); - destroy_workqueue(dfscache_wq); - - cifs_dbg(FYI, "%s: destroyed DFS referral cache\n", __func__); -} - -/* Update a cache entry with the new referral in @refs */ -static int update_cache_entry_locked(struct cache_entry *ce, const struct dfs_info3_param *refs, - int numrefs) -{ - int rc; - char *s, *th = NULL; - - WARN_ON(!rwsem_is_locked(&htable_rw_lock)); - - if (ce->tgthint) { - s = ce->tgthint->name; - th = kstrdup(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 char *path, - struct dfs_info3_param **refs, int *numrefs) -{ - int rc; - int i; - - cifs_dbg(FYI, "%s: get an DFS referral for %s\n", __func__, path); - - *refs = NULL; - *numrefs = 0; - - if (!ses || !ses->server || !ses->server->ops->get_dfs_refer) - return -EOPNOTSUPP; - if (unlikely(!cache_cp)) - return -EINVAL; - - rc = ses->server->ops->get_dfs_refer(xid, ses, path, refs, numrefs, cache_cp, - NO_MAP_UNI_RSVD); - if (!rc) { - struct dfs_info3_param *ref = *refs; - - for (i = 0; i < *numrefs; i++) - convert_delimiter(ref[i].path_name, '\\'); - } - 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_mount() and expand_dfs_referral() are supposed to - * handle them properly. - */ -static int cache_refresh_path(const unsigned int xid, struct cifs_ses *ses, const char *path) -{ - int rc; - 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_write(&htable_rw_lock); - - ce = lookup_cache_entry(path); - if (!IS_ERR(ce)) { - if (!cache_entry_expired(ce)) { - dump_ce(ce); - up_write(&htable_rw_lock); - return 0; - } - } else { - newent = true; - } - - /* - * Either the entry was not found, or it is expired. - * Request a new DFS referral in order to create or update a cache entry. - */ - rc = get_dfs_referral(xid, ses, path, &refs, &numrefs); - if (rc) - goto out_unlock; - - dump_refs(refs, numrefs); - - if (!newent) { - rc = update_cache_entry_locked(ce, refs, numrefs); - goto out_unlock; - } - - rc = add_cache_entry_locked(refs, numrefs); - -out_unlock: - up_write(&htable_rw_lock); - 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 = kstrdup(path, GFP_ATOMIC); - if (!ref->path_name) - return -ENOMEM; - - ref->node_name = kstrdup(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->ref_flags; - ref->flags = ce->hdr_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 = kstrdup(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) { - list_del(&it->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 - * @cp: codepage - * @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 *cp, - int remap, const char *path, struct dfs_info3_param *ref, - struct dfs_cache_tgt_list *tgt_list) -{ - int rc; - const char *npath; - struct cache_entry *ce; - - npath = dfs_cache_canonical_path(path, cp, remap); - if (IS_ERR(npath)) - return PTR_ERR(npath); - - rc = cache_refresh_path(xid, ses, npath); - if (rc) - goto out_free_path; - - down_read(&htable_rw_lock); - - ce = lookup_cache_entry(npath); - 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: - kfree(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: canonical DFS 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; - struct cache_entry *ce; - - cifs_dbg(FYI, "%s: path: %s\n", __func__, path); - - down_read(&htable_rw_lock); - - ce = lookup_cache_entry(path); - 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); - 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 - * @cp: codepage - * @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 *cp, int remap, const char *path, - const struct dfs_cache_tgt_iterator *it) -{ - int rc; - const char *npath; - struct cache_entry *ce; - struct cache_dfs_tgt *t; - - npath = dfs_cache_canonical_path(path, cp, remap); - if (IS_ERR(npath)) - return PTR_ERR(npath); - - cifs_dbg(FYI, "%s: update target hint - path: %s\n", __func__, npath); - - rc = cache_refresh_path(xid, ses, npath); - if (rc) - goto out_free_path; - - down_write(&htable_rw_lock); - - ce = lookup_cache_entry(npath); - 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: - kfree(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: canonical DFS 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; - struct cache_entry *ce; - struct cache_dfs_tgt *t; - - if (!it) - return -EINVAL; - - cifs_dbg(FYI, "%s: path: %s\n", __func__, path); - - down_write(&htable_rw_lock); - - ce = lookup_cache_entry(path); - 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); - return rc; -} - -/** - * dfs_cache_get_tgt_referral - returns a DFS referral (@ref) from a given - * target iterator (@it). - * - * @path: canonical DFS 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; - struct cache_entry *ce; - - if (!it || !ref) - return -EINVAL; - - cifs_dbg(FYI, "%s: path: %s\n", __func__, path); - - down_read(&htable_rw_lock); - - ce = lookup_cache_entry(path); - 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); - return rc; -} - -/** - * dfs_cache_add_refsrv_session - add SMB session of referral server - * - * @mount_id: mount group uuid to lookup. - * @ses: reference counted SMB session of referral server. - */ -void dfs_cache_add_refsrv_session(const uuid_t *mount_id, struct cifs_ses *ses) -{ - struct mount_group *mg; - - if (WARN_ON_ONCE(!mount_id || uuid_is_null(mount_id) || !ses)) - return; - - mg = get_mount_group(mount_id); - if (WARN_ON_ONCE(IS_ERR(mg))) - return; - - spin_lock(&mg->lock); - if (mg->num_sessions < ARRAY_SIZE(mg->sessions)) - mg->sessions[mg->num_sessions++] = ses; - spin_unlock(&mg->lock); - kref_put(&mg->refcount, mount_group_release); -} - -/** - * dfs_cache_put_refsrv_sessions - put all referral server sessions - * - * Put all SMB sessions from the given mount group id. - * - * @mount_id: mount group uuid to lookup. - */ -void dfs_cache_put_refsrv_sessions(const uuid_t *mount_id) -{ - struct mount_group *mg; - - if (!mount_id || uuid_is_null(mount_id)) - return; - - mutex_lock(&mount_group_list_lock); - mg = find_mount_group_locked(mount_id); - if (IS_ERR(mg)) { - mutex_unlock(&mount_group_list_lock); - return; - } - mutex_unlock(&mount_group_list_lock); - kref_put(&mg->refcount, mount_group_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; -} - -static bool target_share_equal(struct TCP_Server_Info *server, const char *s1, const char *s2) -{ - char unc[sizeof("\\\\") + SERVER_NAME_LENGTH] = {0}; - const char *host; - size_t hostlen; - char *ip = NULL; - struct sockaddr sa; - bool match; - int rc; - - if (strcasecmp(s1, s2)) - return false; - - /* - * Resolve share's hostname and check if server address matches. Otherwise just ignore it - * as we could not have upcall to resolve hostname or failed to convert ip address. - */ - match = true; - extract_unc_hostname(s1, &host, &hostlen); - scnprintf(unc, sizeof(unc), "\\\\%.*s", (int)hostlen, host); - - rc = dns_resolve_server_name_to_ip(unc, &ip, NULL); - if (rc < 0) { - cifs_dbg(FYI, "%s: could not resolve %.*s. assuming server address matches.\n", - __func__, (int)hostlen, host); - return true; - } - - if (!cifs_convert_address(&sa, ip, strlen(ip))) { - cifs_dbg(VFS, "%s: failed to convert address \'%s\'. skip address matching.\n", - __func__, ip); - } else { - mutex_lock(&server->srv_mutex); - match = cifs_match_ipaddr((struct sockaddr *)&server->dstaddr, &sa); - mutex_unlock(&server->srv_mutex); - } - - kfree(ip); - return match; -} - -/* - * Mark dfs tcon for reconnecting when the currently connected tcon does not match any of the new - * target shares in @refs. - */ -static void mark_for_reconnect_if_needed(struct cifs_tcon *tcon, struct dfs_cache_tgt_list *tl, - const struct dfs_info3_param *refs, int numrefs) -{ - struct dfs_cache_tgt_iterator *it; - int i; - - for (it = dfs_cache_get_tgt_iterator(tl); it; it = dfs_cache_get_next_tgt(tl, it)) { - for (i = 0; i < numrefs; i++) { - if (target_share_equal(tcon->ses->server, dfs_cache_get_tgt_name(it), - refs[i].node_name)) - return; - } - } - - cifs_dbg(FYI, "%s: no cached or matched targets. mark dfs share for reconnect.\n", __func__); - cifs_reconnect(tcon->ses->server, true); -} - -/* Refresh dfs referral of tcon and mark it for reconnect if needed */ -static int __refresh_tcon(const char *path, struct cifs_ses **sessions, struct cifs_tcon *tcon, - bool force_refresh) -{ - struct cifs_ses *ses; - struct cache_entry *ce; - struct dfs_info3_param *refs = NULL; - int numrefs = 0; - bool needs_refresh = false; - struct dfs_cache_tgt_list tl = DFS_CACHE_TGT_LIST_INIT(tl); - int rc = 0; - unsigned int xid; - - ses = find_ipc_from_server_path(sessions, path); - if (IS_ERR(ses)) { - cifs_dbg(FYI, "%s: could not find ipc session\n", __func__); - return PTR_ERR(ses); - } - - down_read(&htable_rw_lock); - ce = lookup_cache_entry(path); - needs_refresh = force_refresh || IS_ERR(ce) || cache_entry_expired(ce); - if (!IS_ERR(ce)) { - rc = get_targets(ce, &tl); - if (rc) - cifs_dbg(FYI, "%s: could not get dfs targets: %d\n", __func__, rc); - } - up_read(&htable_rw_lock); - - if (!needs_refresh) { - rc = 0; - goto out; - } - - xid = get_xid(); - rc = get_dfs_referral(xid, ses, path, &refs, &numrefs); - free_xid(xid); - - /* Create or update a cache entry with the new referral */ - if (!rc) { - dump_refs(refs, numrefs); - - down_write(&htable_rw_lock); - ce = lookup_cache_entry(path); - if (IS_ERR(ce)) - add_cache_entry_locked(refs, numrefs); - else if (force_refresh || cache_entry_expired(ce)) - update_cache_entry_locked(ce, refs, numrefs); - up_write(&htable_rw_lock); - - mark_for_reconnect_if_needed(tcon, &tl, refs, numrefs); - } - -out: - dfs_cache_free_tgts(&tl); - free_dfs_info_array(refs, numrefs); - return rc; -} - -static int refresh_tcon(struct cifs_ses **sessions, struct cifs_tcon *tcon, bool force_refresh) -{ - struct TCP_Server_Info *server = tcon->ses->server; - - mutex_lock(&server->refpath_lock); - if (strcasecmp(server->leaf_fullpath, server->origin_fullpath)) - __refresh_tcon(server->leaf_fullpath + 1, sessions, tcon, force_refresh); - mutex_unlock(&server->refpath_lock); - - __refresh_tcon(server->origin_fullpath + 1, sessions, tcon, force_refresh); - - return 0; -} - -/** - * dfs_cache_remount_fs - remount a DFS share - * - * Reconfigure dfs mount by forcing a new DFS referral and if the currently cached targets do not - * match any of the new targets, mark it for reconnect. - * - * @cifs_sb: cifs superblock. - * - * Return zero if remounted, otherwise non-zero. - */ -int dfs_cache_remount_fs(struct cifs_sb_info *cifs_sb) -{ - struct cifs_tcon *tcon; - struct TCP_Server_Info *server; - struct mount_group *mg; - struct cifs_ses *sessions[CACHE_MAX_ENTRIES + 1] = {NULL}; - int rc; - - if (!cifs_sb || !cifs_sb->master_tlink) - return -EINVAL; - - tcon = cifs_sb_master_tcon(cifs_sb); - server = tcon->ses->server; - - if (!server->origin_fullpath) { - cifs_dbg(FYI, "%s: not a dfs mount\n", __func__); - return 0; - } - - if (uuid_is_null(&cifs_sb->dfs_mount_id)) { - cifs_dbg(FYI, "%s: no dfs mount group id\n", __func__); - return -EINVAL; - } - - mutex_lock(&mount_group_list_lock); - mg = find_mount_group_locked(&cifs_sb->dfs_mount_id); - if (IS_ERR(mg)) { - mutex_unlock(&mount_group_list_lock); - cifs_dbg(FYI, "%s: no ipc session for refreshing referral\n", __func__); - return PTR_ERR(mg); - } - kref_get(&mg->refcount); - mutex_unlock(&mount_group_list_lock); - - spin_lock(&mg->lock); - memcpy(&sessions, mg->sessions, mg->num_sessions * sizeof(mg->sessions[0])); - spin_unlock(&mg->lock); - - /* - * After reconnecting to a different server, unique ids won't match anymore, so we disable - * serverino. This prevents dentry revalidation to think the dentry are stale (ESTALE). - */ - cifs_autodisable_serverino(cifs_sb); - /* - * Force the use of prefix path to support failover on DFS paths that resolve to targets - * that have different prefix paths. - */ - cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_USE_PREFIX_PATH; - rc = refresh_tcon(sessions, tcon, true); - - kref_put(&mg->refcount, mount_group_release); - return rc; -} - -/* - * Refresh all active dfs mounts regardless of whether they are in cache or not. - * (cache can be cleared) - */ -static void refresh_mounts(struct cifs_ses **sessions) -{ - struct TCP_Server_Info *server; - struct cifs_ses *ses; - struct cifs_tcon *tcon, *ntcon; - struct list_head tcons; - - INIT_LIST_HEAD(&tcons); - - spin_lock(&cifs_tcp_ses_lock); - list_for_each_entry(server, &cifs_tcp_ses_list, tcp_ses_list) { - if (!server->is_dfs_conn) - continue; - - list_for_each_entry(ses, &server->smb_ses_list, smb_ses_list) { - list_for_each_entry(tcon, &ses->tcon_list, tcon_list) { - if (!tcon->ipc && !tcon->need_reconnect) { - tcon->tc_count++; - list_add_tail(&tcon->ulist, &tcons); - } - } - } - } - spin_unlock(&cifs_tcp_ses_lock); - - list_for_each_entry_safe(tcon, ntcon, &tcons, ulist) { - struct TCP_Server_Info *server = tcon->ses->server; - - list_del_init(&tcon->ulist); - - mutex_lock(&server->refpath_lock); - if (strcasecmp(server->leaf_fullpath, server->origin_fullpath)) - __refresh_tcon(server->leaf_fullpath + 1, sessions, tcon, false); - mutex_unlock(&server->refpath_lock); - - __refresh_tcon(server->origin_fullpath + 1, sessions, tcon, false); - cifs_put_tcon(tcon); - } -} - -static void refresh_cache(struct cifs_ses **sessions) -{ - int i; - struct cifs_ses *ses; - unsigned int xid; - char *ref_paths[CACHE_MAX_ENTRIES]; - int count = 0; - struct cache_entry *ce; - - /* - * Refresh all cached entries. Get all new referrals outside critical section to avoid - * starvation while performing SMB2 IOCTL on broken or slow connections. - - * The cache entries may cover more paths than the active mounts - * (e.g. domain-based DFS referrals or multi tier DFS setups). - */ - 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 (count == ARRAY_SIZE(ref_paths)) - goto out_unlock; - if (hlist_unhashed(&ce->hlist) || !cache_entry_expired(ce) || - IS_ERR(find_ipc_from_server_path(sessions, ce->path))) - continue; - ref_paths[count++] = kstrdup(ce->path, GFP_ATOMIC); - } - } - -out_unlock: - up_read(&htable_rw_lock); - - for (i = 0; i < count; i++) { - char *path = ref_paths[i]; - struct dfs_info3_param *refs = NULL; - int numrefs = 0; - int rc = 0; - - if (!path) - continue; - - ses = find_ipc_from_server_path(sessions, path); - if (IS_ERR(ses)) - goto next_referral; - - xid = get_xid(); - rc = get_dfs_referral(xid, ses, path, &refs, &numrefs); - free_xid(xid); - - if (!rc) { - down_write(&htable_rw_lock); - ce = lookup_cache_entry(path); - /* - * We need to re-check it because other tasks might have it deleted or - * updated. - */ - if (!IS_ERR(ce) && cache_entry_expired(ce)) - update_cache_entry_locked(ce, refs, numrefs); - up_write(&htable_rw_lock); - } - -next_referral: - kfree(path); - free_dfs_info_array(refs, numrefs); - } -} - -/* - * Worker that will refresh DFS cache and active mounts based on lowest TTL value from a DFS - * referral. - */ -static void refresh_cache_worker(struct work_struct *work) -{ - struct list_head mglist; - struct mount_group *mg, *tmp_mg; - struct cifs_ses *sessions[CACHE_MAX_ENTRIES + 1] = {NULL}; - int max_sessions = ARRAY_SIZE(sessions) - 1; - int i = 0, count; - - INIT_LIST_HEAD(&mglist); - - /* Get refereces of mount groups */ - mutex_lock(&mount_group_list_lock); - list_for_each_entry(mg, &mount_group_list, list) { - kref_get(&mg->refcount); - list_add(&mg->refresh_list, &mglist); - } - mutex_unlock(&mount_group_list_lock); - - /* Fill in local array with an NULL-terminated list of all referral server sessions */ - list_for_each_entry(mg, &mglist, refresh_list) { - if (i >= max_sessions) - break; - - spin_lock(&mg->lock); - if (i + mg->num_sessions > max_sessions) - count = max_sessions - i; - else - count = mg->num_sessions; - memcpy(&sessions[i], mg->sessions, count * sizeof(mg->sessions[0])); - spin_unlock(&mg->lock); - i += count; - } - - if (sessions[0]) { - /* Refresh all active mounts and cached entries */ - refresh_mounts(sessions); - refresh_cache(sessions); - } - - list_for_each_entry_safe(mg, tmp_mg, &mglist, refresh_list) { - list_del_init(&mg->refresh_list); - kref_put(&mg->refcount, mount_group_release); - } - - spin_lock(&cache_ttl_lock); - queue_delayed_work(dfscache_wq, &refresh_task, cache_ttl * HZ); - spin_unlock(&cache_ttl_lock); -} |