1b8441ed2STejun Heo /* 2b8441ed2STejun Heo * fs/kernfs/dir.c - kernfs directory implementation 3b8441ed2STejun Heo * 4b8441ed2STejun Heo * Copyright (c) 2001-3 Patrick Mochel 5b8441ed2STejun Heo * Copyright (c) 2007 SUSE Linux Products GmbH 6b8441ed2STejun Heo * Copyright (c) 2007, 2013 Tejun Heo <tj@kernel.org> 7b8441ed2STejun Heo * 8b8441ed2STejun Heo * This file is released under the GPLv2. 9b8441ed2STejun Heo */ 10fd7b9f7bSTejun Heo 11abd54f02STejun Heo #include <linux/sched.h> 12fd7b9f7bSTejun Heo #include <linux/fs.h> 13fd7b9f7bSTejun Heo #include <linux/namei.h> 14fd7b9f7bSTejun Heo #include <linux/idr.h> 15fd7b9f7bSTejun Heo #include <linux/slab.h> 16fd7b9f7bSTejun Heo #include <linux/security.h> 17fd7b9f7bSTejun Heo #include <linux/hash.h> 18fd7b9f7bSTejun Heo 19fd7b9f7bSTejun Heo #include "kernfs-internal.h" 20fd7b9f7bSTejun Heo 21a797bfc3STejun Heo DEFINE_MUTEX(kernfs_mutex); 223eef34adSTejun Heo static DEFINE_SPINLOCK(kernfs_rename_lock); /* kn->parent and ->name */ 233eef34adSTejun Heo static char kernfs_pr_cont_buf[PATH_MAX]; /* protected by rename_lock */ 24fd7b9f7bSTejun Heo 25adc5e8b5STejun Heo #define rb_to_kn(X) rb_entry((X), struct kernfs_node, rb) 26fd7b9f7bSTejun Heo 2781c173cbSTejun Heo static bool kernfs_active(struct kernfs_node *kn) 2881c173cbSTejun Heo { 2981c173cbSTejun Heo lockdep_assert_held(&kernfs_mutex); 3081c173cbSTejun Heo return atomic_read(&kn->active) >= 0; 3181c173cbSTejun Heo } 3281c173cbSTejun Heo 33182fd64bSTejun Heo static bool kernfs_lockdep(struct kernfs_node *kn) 34182fd64bSTejun Heo { 35182fd64bSTejun Heo #ifdef CONFIG_DEBUG_LOCK_ALLOC 36182fd64bSTejun Heo return kn->flags & KERNFS_LOCKDEP; 37182fd64bSTejun Heo #else 38182fd64bSTejun Heo return false; 39182fd64bSTejun Heo #endif 40182fd64bSTejun Heo } 41182fd64bSTejun Heo 423eef34adSTejun Heo static int kernfs_name_locked(struct kernfs_node *kn, char *buf, size_t buflen) 433eef34adSTejun Heo { 443eef34adSTejun Heo return strlcpy(buf, kn->parent ? kn->name : "/", buflen); 453eef34adSTejun Heo } 463eef34adSTejun Heo 479f6df573SAditya Kali /* kernfs_node_depth - compute depth from @from to @to */ 489f6df573SAditya Kali static size_t kernfs_depth(struct kernfs_node *from, struct kernfs_node *to) 493eef34adSTejun Heo { 509f6df573SAditya Kali size_t depth = 0; 513eef34adSTejun Heo 529f6df573SAditya Kali while (to->parent && to != from) { 539f6df573SAditya Kali depth++; 549f6df573SAditya Kali to = to->parent; 553eef34adSTejun Heo } 569f6df573SAditya Kali return depth; 579f6df573SAditya Kali } 583eef34adSTejun Heo 599f6df573SAditya Kali static struct kernfs_node *kernfs_common_ancestor(struct kernfs_node *a, 609f6df573SAditya Kali struct kernfs_node *b) 619f6df573SAditya Kali { 629f6df573SAditya Kali size_t da, db; 639f6df573SAditya Kali struct kernfs_root *ra = kernfs_root(a), *rb = kernfs_root(b); 649f6df573SAditya Kali 659f6df573SAditya Kali if (ra != rb) 669f6df573SAditya Kali return NULL; 679f6df573SAditya Kali 689f6df573SAditya Kali da = kernfs_depth(ra->kn, a); 699f6df573SAditya Kali db = kernfs_depth(rb->kn, b); 709f6df573SAditya Kali 719f6df573SAditya Kali while (da > db) { 729f6df573SAditya Kali a = a->parent; 739f6df573SAditya Kali da--; 749f6df573SAditya Kali } 759f6df573SAditya Kali while (db > da) { 769f6df573SAditya Kali b = b->parent; 779f6df573SAditya Kali db--; 789f6df573SAditya Kali } 799f6df573SAditya Kali 809f6df573SAditya Kali /* worst case b and a will be the same at root */ 819f6df573SAditya Kali while (b != a) { 829f6df573SAditya Kali b = b->parent; 839f6df573SAditya Kali a = a->parent; 849f6df573SAditya Kali } 859f6df573SAditya Kali 869f6df573SAditya Kali return a; 879f6df573SAditya Kali } 889f6df573SAditya Kali 899f6df573SAditya Kali /** 909f6df573SAditya Kali * kernfs_path_from_node_locked - find a pseudo-absolute path to @kn_to, 919f6df573SAditya Kali * where kn_from is treated as root of the path. 929f6df573SAditya Kali * @kn_from: kernfs node which should be treated as root for the path 939f6df573SAditya Kali * @kn_to: kernfs node to which path is needed 949f6df573SAditya Kali * @buf: buffer to copy the path into 959f6df573SAditya Kali * @buflen: size of @buf 969f6df573SAditya Kali * 979f6df573SAditya Kali * We need to handle couple of scenarios here: 989f6df573SAditya Kali * [1] when @kn_from is an ancestor of @kn_to at some level 999f6df573SAditya Kali * kn_from: /n1/n2/n3 1009f6df573SAditya Kali * kn_to: /n1/n2/n3/n4/n5 1019f6df573SAditya Kali * result: /n4/n5 1029f6df573SAditya Kali * 1039f6df573SAditya Kali * [2] when @kn_from is on a different hierarchy and we need to find common 1049f6df573SAditya Kali * ancestor between @kn_from and @kn_to. 1059f6df573SAditya Kali * kn_from: /n1/n2/n3/n4 1069f6df573SAditya Kali * kn_to: /n1/n2/n5 1079f6df573SAditya Kali * result: /../../n5 1089f6df573SAditya Kali * OR 1099f6df573SAditya Kali * kn_from: /n1/n2/n3/n4/n5 [depth=5] 1109f6df573SAditya Kali * kn_to: /n1/n2/n3 [depth=3] 1119f6df573SAditya Kali * result: /../.. 1129f6df573SAditya Kali * 1139f6df573SAditya Kali * return value: length of the string. If greater than buflen, 1149f6df573SAditya Kali * then contents of buf are undefined. On error, -1 is returned. 1159f6df573SAditya Kali */ 1169f6df573SAditya Kali static int kernfs_path_from_node_locked(struct kernfs_node *kn_to, 1179f6df573SAditya Kali struct kernfs_node *kn_from, 1189f6df573SAditya Kali char *buf, size_t buflen) 1199f6df573SAditya Kali { 1209f6df573SAditya Kali struct kernfs_node *kn, *common; 1219f6df573SAditya Kali const char parent_str[] = "/.."; 1229f6df573SAditya Kali size_t depth_from, depth_to, len = 0, nlen = 0; 1239f6df573SAditya Kali char *p; 1249f6df573SAditya Kali int i; 1259f6df573SAditya Kali 1269f6df573SAditya Kali if (!kn_from) 1279f6df573SAditya Kali kn_from = kernfs_root(kn_to)->kn; 1289f6df573SAditya Kali 1299f6df573SAditya Kali if (kn_from == kn_to) 1309f6df573SAditya Kali return strlcpy(buf, "/", buflen); 1319f6df573SAditya Kali 1329f6df573SAditya Kali common = kernfs_common_ancestor(kn_from, kn_to); 1339f6df573SAditya Kali if (WARN_ON(!common)) 1349f6df573SAditya Kali return -1; 1359f6df573SAditya Kali 1369f6df573SAditya Kali depth_to = kernfs_depth(common, kn_to); 1379f6df573SAditya Kali depth_from = kernfs_depth(common, kn_from); 1389f6df573SAditya Kali 1399f6df573SAditya Kali if (buf) 1409f6df573SAditya Kali buf[0] = '\0'; 1419f6df573SAditya Kali 1429f6df573SAditya Kali for (i = 0; i < depth_from; i++) 1439f6df573SAditya Kali len += strlcpy(buf + len, parent_str, 1449f6df573SAditya Kali len < buflen ? buflen - len : 0); 1459f6df573SAditya Kali 1469f6df573SAditya Kali /* Calculate how many bytes we need for the rest */ 1479f6df573SAditya Kali for (kn = kn_to; kn != common; kn = kn->parent) 1489f6df573SAditya Kali nlen += strlen(kn->name) + 1; 1499f6df573SAditya Kali 1509f6df573SAditya Kali if (len + nlen >= buflen) 1519f6df573SAditya Kali return len + nlen; 1529f6df573SAditya Kali 1539f6df573SAditya Kali p = buf + len + nlen; 1549f6df573SAditya Kali *p = '\0'; 1559f6df573SAditya Kali for (kn = kn_to; kn != common; kn = kn->parent) { 1569f6df573SAditya Kali nlen = strlen(kn->name); 1579f6df573SAditya Kali p -= nlen; 1589f6df573SAditya Kali memcpy(p, kn->name, nlen); 1599f6df573SAditya Kali *(--p) = '/'; 1609f6df573SAditya Kali } 1619f6df573SAditya Kali 1629f6df573SAditya Kali return len + nlen; 1633eef34adSTejun Heo } 1643eef34adSTejun Heo 1653eef34adSTejun Heo /** 1663eef34adSTejun Heo * kernfs_name - obtain the name of a given node 1673eef34adSTejun Heo * @kn: kernfs_node of interest 1683eef34adSTejun Heo * @buf: buffer to copy @kn's name into 1693eef34adSTejun Heo * @buflen: size of @buf 1703eef34adSTejun Heo * 1713eef34adSTejun Heo * Copies the name of @kn into @buf of @buflen bytes. The behavior is 1723eef34adSTejun Heo * similar to strlcpy(). It returns the length of @kn's name and if @buf 1733eef34adSTejun Heo * isn't long enough, it's filled upto @buflen-1 and nul terminated. 1743eef34adSTejun Heo * 1753eef34adSTejun Heo * This function can be called from any context. 1763eef34adSTejun Heo */ 1773eef34adSTejun Heo int kernfs_name(struct kernfs_node *kn, char *buf, size_t buflen) 1783eef34adSTejun Heo { 1793eef34adSTejun Heo unsigned long flags; 1803eef34adSTejun Heo int ret; 1813eef34adSTejun Heo 1823eef34adSTejun Heo spin_lock_irqsave(&kernfs_rename_lock, flags); 1833eef34adSTejun Heo ret = kernfs_name_locked(kn, buf, buflen); 1843eef34adSTejun Heo spin_unlock_irqrestore(&kernfs_rename_lock, flags); 1853eef34adSTejun Heo return ret; 1863eef34adSTejun Heo } 1873eef34adSTejun Heo 1883eef34adSTejun Heo /** 1899acee9c5STejun Heo * kernfs_path_len - determine the length of the full path of a given node 1909acee9c5STejun Heo * @kn: kernfs_node of interest 1919acee9c5STejun Heo * 1929acee9c5STejun Heo * The returned length doesn't include the space for the terminating '\0'. 1939acee9c5STejun Heo */ 1949acee9c5STejun Heo size_t kernfs_path_len(struct kernfs_node *kn) 1959acee9c5STejun Heo { 1969acee9c5STejun Heo size_t len = 0; 1979acee9c5STejun Heo unsigned long flags; 1989acee9c5STejun Heo 1999acee9c5STejun Heo spin_lock_irqsave(&kernfs_rename_lock, flags); 2009acee9c5STejun Heo 2019acee9c5STejun Heo do { 2029acee9c5STejun Heo len += strlen(kn->name) + 1; 2039acee9c5STejun Heo kn = kn->parent; 2049acee9c5STejun Heo } while (kn && kn->parent); 2059acee9c5STejun Heo 2069acee9c5STejun Heo spin_unlock_irqrestore(&kernfs_rename_lock, flags); 2079acee9c5STejun Heo 2089acee9c5STejun Heo return len; 2099acee9c5STejun Heo } 2109acee9c5STejun Heo 2119acee9c5STejun Heo /** 2129f6df573SAditya Kali * kernfs_path_from_node - build path of node @to relative to @from. 2139f6df573SAditya Kali * @from: parent kernfs_node relative to which we need to build the path 2149f6df573SAditya Kali * @to: kernfs_node of interest 2159f6df573SAditya Kali * @buf: buffer to copy @to's path into 2169f6df573SAditya Kali * @buflen: size of @buf 2179f6df573SAditya Kali * 2189f6df573SAditya Kali * Builds @to's path relative to @from in @buf. @from and @to must 2199f6df573SAditya Kali * be on the same kernfs-root. If @from is not parent of @to, then a relative 2209f6df573SAditya Kali * path (which includes '..'s) as needed to reach from @from to @to is 2219f6df573SAditya Kali * returned. 2229f6df573SAditya Kali * 2239f6df573SAditya Kali * If @buf isn't long enough, the return value will be greater than @buflen 2249f6df573SAditya Kali * and @buf contents are undefined. 2259f6df573SAditya Kali */ 2269f6df573SAditya Kali int kernfs_path_from_node(struct kernfs_node *to, struct kernfs_node *from, 2279f6df573SAditya Kali char *buf, size_t buflen) 2289f6df573SAditya Kali { 2299f6df573SAditya Kali unsigned long flags; 2309f6df573SAditya Kali int ret; 2319f6df573SAditya Kali 2329f6df573SAditya Kali spin_lock_irqsave(&kernfs_rename_lock, flags); 2339f6df573SAditya Kali ret = kernfs_path_from_node_locked(to, from, buf, buflen); 2349f6df573SAditya Kali spin_unlock_irqrestore(&kernfs_rename_lock, flags); 2359f6df573SAditya Kali return ret; 2369f6df573SAditya Kali } 2379f6df573SAditya Kali EXPORT_SYMBOL_GPL(kernfs_path_from_node); 2389f6df573SAditya Kali 2399f6df573SAditya Kali /** 2403eef34adSTejun Heo * kernfs_path - build full path of a given node 2413eef34adSTejun Heo * @kn: kernfs_node of interest 2423eef34adSTejun Heo * @buf: buffer to copy @kn's name into 2433eef34adSTejun Heo * @buflen: size of @buf 2443eef34adSTejun Heo * 2453eef34adSTejun Heo * Builds and returns the full path of @kn in @buf of @buflen bytes. The 2463eef34adSTejun Heo * path is built from the end of @buf so the returned pointer usually 2473eef34adSTejun Heo * doesn't match @buf. If @buf isn't long enough, @buf is nul terminated 2483eef34adSTejun Heo * and %NULL is returned. 2493eef34adSTejun Heo */ 2503eef34adSTejun Heo char *kernfs_path(struct kernfs_node *kn, char *buf, size_t buflen) 2513eef34adSTejun Heo { 2529f6df573SAditya Kali int ret; 2533eef34adSTejun Heo 2549f6df573SAditya Kali ret = kernfs_path_from_node(kn, NULL, buf, buflen); 2559f6df573SAditya Kali if (ret < 0 || ret >= buflen) 2569f6df573SAditya Kali return NULL; 2579f6df573SAditya Kali return buf; 2583eef34adSTejun Heo } 259e61734c5STejun Heo EXPORT_SYMBOL_GPL(kernfs_path); 2603eef34adSTejun Heo 2613eef34adSTejun Heo /** 2623eef34adSTejun Heo * pr_cont_kernfs_name - pr_cont name of a kernfs_node 2633eef34adSTejun Heo * @kn: kernfs_node of interest 2643eef34adSTejun Heo * 2653eef34adSTejun Heo * This function can be called from any context. 2663eef34adSTejun Heo */ 2673eef34adSTejun Heo void pr_cont_kernfs_name(struct kernfs_node *kn) 2683eef34adSTejun Heo { 2693eef34adSTejun Heo unsigned long flags; 2703eef34adSTejun Heo 2713eef34adSTejun Heo spin_lock_irqsave(&kernfs_rename_lock, flags); 2723eef34adSTejun Heo 2733eef34adSTejun Heo kernfs_name_locked(kn, kernfs_pr_cont_buf, sizeof(kernfs_pr_cont_buf)); 2743eef34adSTejun Heo pr_cont("%s", kernfs_pr_cont_buf); 2753eef34adSTejun Heo 2763eef34adSTejun Heo spin_unlock_irqrestore(&kernfs_rename_lock, flags); 2773eef34adSTejun Heo } 2783eef34adSTejun Heo 2793eef34adSTejun Heo /** 2803eef34adSTejun Heo * pr_cont_kernfs_path - pr_cont path of a kernfs_node 2813eef34adSTejun Heo * @kn: kernfs_node of interest 2823eef34adSTejun Heo * 2833eef34adSTejun Heo * This function can be called from any context. 2843eef34adSTejun Heo */ 2853eef34adSTejun Heo void pr_cont_kernfs_path(struct kernfs_node *kn) 2863eef34adSTejun Heo { 2873eef34adSTejun Heo unsigned long flags; 2889f6df573SAditya Kali int sz; 2893eef34adSTejun Heo 2903eef34adSTejun Heo spin_lock_irqsave(&kernfs_rename_lock, flags); 2913eef34adSTejun Heo 2929f6df573SAditya Kali sz = kernfs_path_from_node_locked(kn, NULL, kernfs_pr_cont_buf, 2933eef34adSTejun Heo sizeof(kernfs_pr_cont_buf)); 2949f6df573SAditya Kali if (sz < 0) { 2959f6df573SAditya Kali pr_cont("(error)"); 2969f6df573SAditya Kali goto out; 2979f6df573SAditya Kali } 2983eef34adSTejun Heo 2999f6df573SAditya Kali if (sz >= sizeof(kernfs_pr_cont_buf)) { 3009f6df573SAditya Kali pr_cont("(name too long)"); 3019f6df573SAditya Kali goto out; 3029f6df573SAditya Kali } 3039f6df573SAditya Kali 3049f6df573SAditya Kali pr_cont("%s", kernfs_pr_cont_buf); 3059f6df573SAditya Kali 3069f6df573SAditya Kali out: 3073eef34adSTejun Heo spin_unlock_irqrestore(&kernfs_rename_lock, flags); 3083eef34adSTejun Heo } 3093eef34adSTejun Heo 3103eef34adSTejun Heo /** 3113eef34adSTejun Heo * kernfs_get_parent - determine the parent node and pin it 3123eef34adSTejun Heo * @kn: kernfs_node of interest 3133eef34adSTejun Heo * 3143eef34adSTejun Heo * Determines @kn's parent, pins and returns it. This function can be 3153eef34adSTejun Heo * called from any context. 3163eef34adSTejun Heo */ 3173eef34adSTejun Heo struct kernfs_node *kernfs_get_parent(struct kernfs_node *kn) 3183eef34adSTejun Heo { 3193eef34adSTejun Heo struct kernfs_node *parent; 3203eef34adSTejun Heo unsigned long flags; 3213eef34adSTejun Heo 3223eef34adSTejun Heo spin_lock_irqsave(&kernfs_rename_lock, flags); 3233eef34adSTejun Heo parent = kn->parent; 3243eef34adSTejun Heo kernfs_get(parent); 3253eef34adSTejun Heo spin_unlock_irqrestore(&kernfs_rename_lock, flags); 3263eef34adSTejun Heo 3273eef34adSTejun Heo return parent; 3283eef34adSTejun Heo } 3293eef34adSTejun Heo 330fd7b9f7bSTejun Heo /** 331c637b8acSTejun Heo * kernfs_name_hash 332fd7b9f7bSTejun Heo * @name: Null terminated string to hash 333fd7b9f7bSTejun Heo * @ns: Namespace tag to hash 334fd7b9f7bSTejun Heo * 335fd7b9f7bSTejun Heo * Returns 31 bit hash of ns + name (so it fits in an off_t ) 336fd7b9f7bSTejun Heo */ 337c637b8acSTejun Heo static unsigned int kernfs_name_hash(const char *name, const void *ns) 338fd7b9f7bSTejun Heo { 339fd7b9f7bSTejun Heo unsigned long hash = init_name_hash(); 340fd7b9f7bSTejun Heo unsigned int len = strlen(name); 341fd7b9f7bSTejun Heo while (len--) 342fd7b9f7bSTejun Heo hash = partial_name_hash(*name++, hash); 343fd7b9f7bSTejun Heo hash = (end_name_hash(hash) ^ hash_ptr((void *)ns, 31)); 344fd7b9f7bSTejun Heo hash &= 0x7fffffffU; 345fd7b9f7bSTejun Heo /* Reserve hash numbers 0, 1 and INT_MAX for magic directory entries */ 34688391d49SRichard Cochran if (hash < 2) 347fd7b9f7bSTejun Heo hash += 2; 348fd7b9f7bSTejun Heo if (hash >= INT_MAX) 349fd7b9f7bSTejun Heo hash = INT_MAX - 1; 350fd7b9f7bSTejun Heo return hash; 351fd7b9f7bSTejun Heo } 352fd7b9f7bSTejun Heo 353c637b8acSTejun Heo static int kernfs_name_compare(unsigned int hash, const char *name, 354324a56e1STejun Heo const void *ns, const struct kernfs_node *kn) 355fd7b9f7bSTejun Heo { 35672392ed0SRasmus Villemoes if (hash < kn->hash) 35772392ed0SRasmus Villemoes return -1; 35872392ed0SRasmus Villemoes if (hash > kn->hash) 35972392ed0SRasmus Villemoes return 1; 36072392ed0SRasmus Villemoes if (ns < kn->ns) 36172392ed0SRasmus Villemoes return -1; 36272392ed0SRasmus Villemoes if (ns > kn->ns) 36372392ed0SRasmus Villemoes return 1; 364adc5e8b5STejun Heo return strcmp(name, kn->name); 365fd7b9f7bSTejun Heo } 366fd7b9f7bSTejun Heo 367c637b8acSTejun Heo static int kernfs_sd_compare(const struct kernfs_node *left, 368324a56e1STejun Heo const struct kernfs_node *right) 369fd7b9f7bSTejun Heo { 370c637b8acSTejun Heo return kernfs_name_compare(left->hash, left->name, left->ns, right); 371fd7b9f7bSTejun Heo } 372fd7b9f7bSTejun Heo 373fd7b9f7bSTejun Heo /** 374c637b8acSTejun Heo * kernfs_link_sibling - link kernfs_node into sibling rbtree 375324a56e1STejun Heo * @kn: kernfs_node of interest 376fd7b9f7bSTejun Heo * 377324a56e1STejun Heo * Link @kn into its sibling rbtree which starts from 378adc5e8b5STejun Heo * @kn->parent->dir.children. 379fd7b9f7bSTejun Heo * 380fd7b9f7bSTejun Heo * Locking: 381a797bfc3STejun Heo * mutex_lock(kernfs_mutex) 382fd7b9f7bSTejun Heo * 383fd7b9f7bSTejun Heo * RETURNS: 384fd7b9f7bSTejun Heo * 0 on susccess -EEXIST on failure. 385fd7b9f7bSTejun Heo */ 386c637b8acSTejun Heo static int kernfs_link_sibling(struct kernfs_node *kn) 387fd7b9f7bSTejun Heo { 388adc5e8b5STejun Heo struct rb_node **node = &kn->parent->dir.children.rb_node; 389fd7b9f7bSTejun Heo struct rb_node *parent = NULL; 390fd7b9f7bSTejun Heo 391fd7b9f7bSTejun Heo while (*node) { 392324a56e1STejun Heo struct kernfs_node *pos; 393fd7b9f7bSTejun Heo int result; 394fd7b9f7bSTejun Heo 395324a56e1STejun Heo pos = rb_to_kn(*node); 396fd7b9f7bSTejun Heo parent = *node; 397c637b8acSTejun Heo result = kernfs_sd_compare(kn, pos); 398fd7b9f7bSTejun Heo if (result < 0) 399adc5e8b5STejun Heo node = &pos->rb.rb_left; 400fd7b9f7bSTejun Heo else if (result > 0) 401adc5e8b5STejun Heo node = &pos->rb.rb_right; 402fd7b9f7bSTejun Heo else 403fd7b9f7bSTejun Heo return -EEXIST; 404fd7b9f7bSTejun Heo } 405c1befb88SJianyu Zhan 406fd7b9f7bSTejun Heo /* add new node and rebalance the tree */ 407adc5e8b5STejun Heo rb_link_node(&kn->rb, parent, node); 408adc5e8b5STejun Heo rb_insert_color(&kn->rb, &kn->parent->dir.children); 409c1befb88SJianyu Zhan 410c1befb88SJianyu Zhan /* successfully added, account subdir number */ 411c1befb88SJianyu Zhan if (kernfs_type(kn) == KERNFS_DIR) 412c1befb88SJianyu Zhan kn->parent->dir.subdirs++; 413c1befb88SJianyu Zhan 414fd7b9f7bSTejun Heo return 0; 415fd7b9f7bSTejun Heo } 416fd7b9f7bSTejun Heo 417fd7b9f7bSTejun Heo /** 418c637b8acSTejun Heo * kernfs_unlink_sibling - unlink kernfs_node from sibling rbtree 419324a56e1STejun Heo * @kn: kernfs_node of interest 420fd7b9f7bSTejun Heo * 42135beab06STejun Heo * Try to unlink @kn from its sibling rbtree which starts from 42235beab06STejun Heo * kn->parent->dir.children. Returns %true if @kn was actually 42335beab06STejun Heo * removed, %false if @kn wasn't on the rbtree. 424fd7b9f7bSTejun Heo * 425fd7b9f7bSTejun Heo * Locking: 426a797bfc3STejun Heo * mutex_lock(kernfs_mutex) 427fd7b9f7bSTejun Heo */ 42835beab06STejun Heo static bool kernfs_unlink_sibling(struct kernfs_node *kn) 429fd7b9f7bSTejun Heo { 43035beab06STejun Heo if (RB_EMPTY_NODE(&kn->rb)) 43135beab06STejun Heo return false; 43235beab06STejun Heo 433df23fc39STejun Heo if (kernfs_type(kn) == KERNFS_DIR) 434adc5e8b5STejun Heo kn->parent->dir.subdirs--; 435fd7b9f7bSTejun Heo 436adc5e8b5STejun Heo rb_erase(&kn->rb, &kn->parent->dir.children); 43735beab06STejun Heo RB_CLEAR_NODE(&kn->rb); 43835beab06STejun Heo return true; 439fd7b9f7bSTejun Heo } 440fd7b9f7bSTejun Heo 441fd7b9f7bSTejun Heo /** 442c637b8acSTejun Heo * kernfs_get_active - get an active reference to kernfs_node 443324a56e1STejun Heo * @kn: kernfs_node to get an active reference to 444fd7b9f7bSTejun Heo * 445324a56e1STejun Heo * Get an active reference of @kn. This function is noop if @kn 446fd7b9f7bSTejun Heo * is NULL. 447fd7b9f7bSTejun Heo * 448fd7b9f7bSTejun Heo * RETURNS: 449324a56e1STejun Heo * Pointer to @kn on success, NULL on failure. 450fd7b9f7bSTejun Heo */ 451c637b8acSTejun Heo struct kernfs_node *kernfs_get_active(struct kernfs_node *kn) 452fd7b9f7bSTejun Heo { 453324a56e1STejun Heo if (unlikely(!kn)) 454fd7b9f7bSTejun Heo return NULL; 455fd7b9f7bSTejun Heo 456f4b3e631SGreg Kroah-Hartman if (!atomic_inc_unless_negative(&kn->active)) 457f4b3e631SGreg Kroah-Hartman return NULL; 458f4b3e631SGreg Kroah-Hartman 459182fd64bSTejun Heo if (kernfs_lockdep(kn)) 460324a56e1STejun Heo rwsem_acquire_read(&kn->dep_map, 0, 1, _RET_IP_); 461324a56e1STejun Heo return kn; 462fd7b9f7bSTejun Heo } 463fd7b9f7bSTejun Heo 464fd7b9f7bSTejun Heo /** 465c637b8acSTejun Heo * kernfs_put_active - put an active reference to kernfs_node 466324a56e1STejun Heo * @kn: kernfs_node to put an active reference to 467fd7b9f7bSTejun Heo * 468324a56e1STejun Heo * Put an active reference to @kn. This function is noop if @kn 469fd7b9f7bSTejun Heo * is NULL. 470fd7b9f7bSTejun Heo */ 471c637b8acSTejun Heo void kernfs_put_active(struct kernfs_node *kn) 472fd7b9f7bSTejun Heo { 473abd54f02STejun Heo struct kernfs_root *root = kernfs_root(kn); 474fd7b9f7bSTejun Heo int v; 475fd7b9f7bSTejun Heo 476324a56e1STejun Heo if (unlikely(!kn)) 477fd7b9f7bSTejun Heo return; 478fd7b9f7bSTejun Heo 479182fd64bSTejun Heo if (kernfs_lockdep(kn)) 480324a56e1STejun Heo rwsem_release(&kn->dep_map, 1, _RET_IP_); 481adc5e8b5STejun Heo v = atomic_dec_return(&kn->active); 482df23fc39STejun Heo if (likely(v != KN_DEACTIVATED_BIAS)) 483fd7b9f7bSTejun Heo return; 484fd7b9f7bSTejun Heo 485abd54f02STejun Heo wake_up_all(&root->deactivate_waitq); 486fd7b9f7bSTejun Heo } 487fd7b9f7bSTejun Heo 488fd7b9f7bSTejun Heo /** 48981c173cbSTejun Heo * kernfs_drain - drain kernfs_node 49081c173cbSTejun Heo * @kn: kernfs_node to drain 491fd7b9f7bSTejun Heo * 49281c173cbSTejun Heo * Drain existing usages and nuke all existing mmaps of @kn. Mutiple 49381c173cbSTejun Heo * removers may invoke this function concurrently on @kn and all will 49481c173cbSTejun Heo * return after draining is complete. 495fd7b9f7bSTejun Heo */ 49681c173cbSTejun Heo static void kernfs_drain(struct kernfs_node *kn) 49735beab06STejun Heo __releases(&kernfs_mutex) __acquires(&kernfs_mutex) 498fd7b9f7bSTejun Heo { 499abd54f02STejun Heo struct kernfs_root *root = kernfs_root(kn); 500fd7b9f7bSTejun Heo 50135beab06STejun Heo lockdep_assert_held(&kernfs_mutex); 50281c173cbSTejun Heo WARN_ON_ONCE(kernfs_active(kn)); 503abd54f02STejun Heo 50435beab06STejun Heo mutex_unlock(&kernfs_mutex); 505abd54f02STejun Heo 506182fd64bSTejun Heo if (kernfs_lockdep(kn)) { 50735beab06STejun Heo rwsem_acquire(&kn->dep_map, 0, 0, _RET_IP_); 50835beab06STejun Heo if (atomic_read(&kn->active) != KN_DEACTIVATED_BIAS) 50935beab06STejun Heo lock_contended(&kn->dep_map, _RET_IP_); 51035beab06STejun Heo } 51135beab06STejun Heo 51235beab06STejun Heo /* but everyone should wait for draining */ 513abd54f02STejun Heo wait_event(root->deactivate_waitq, 514abd54f02STejun Heo atomic_read(&kn->active) == KN_DEACTIVATED_BIAS); 515fd7b9f7bSTejun Heo 516182fd64bSTejun Heo if (kernfs_lockdep(kn)) { 517324a56e1STejun Heo lock_acquired(&kn->dep_map, _RET_IP_); 518324a56e1STejun Heo rwsem_release(&kn->dep_map, 1, _RET_IP_); 519fd7b9f7bSTejun Heo } 52035beab06STejun Heo 521ccf02aafSTejun Heo kernfs_unmap_bin_file(kn); 522ccf02aafSTejun Heo 52335beab06STejun Heo mutex_lock(&kernfs_mutex); 524a6607930STejun Heo } 525fd7b9f7bSTejun Heo 526fd7b9f7bSTejun Heo /** 527324a56e1STejun Heo * kernfs_get - get a reference count on a kernfs_node 528324a56e1STejun Heo * @kn: the target kernfs_node 529fd7b9f7bSTejun Heo */ 530324a56e1STejun Heo void kernfs_get(struct kernfs_node *kn) 531fd7b9f7bSTejun Heo { 532324a56e1STejun Heo if (kn) { 533adc5e8b5STejun Heo WARN_ON(!atomic_read(&kn->count)); 534adc5e8b5STejun Heo atomic_inc(&kn->count); 535fd7b9f7bSTejun Heo } 536fd7b9f7bSTejun Heo } 537fd7b9f7bSTejun Heo EXPORT_SYMBOL_GPL(kernfs_get); 538fd7b9f7bSTejun Heo 539fd7b9f7bSTejun Heo /** 540324a56e1STejun Heo * kernfs_put - put a reference count on a kernfs_node 541324a56e1STejun Heo * @kn: the target kernfs_node 542fd7b9f7bSTejun Heo * 543324a56e1STejun Heo * Put a reference count of @kn and destroy it if it reached zero. 544fd7b9f7bSTejun Heo */ 545324a56e1STejun Heo void kernfs_put(struct kernfs_node *kn) 546fd7b9f7bSTejun Heo { 547324a56e1STejun Heo struct kernfs_node *parent; 548ba7443bcSTejun Heo struct kernfs_root *root; 549fd7b9f7bSTejun Heo 550adc5e8b5STejun Heo if (!kn || !atomic_dec_and_test(&kn->count)) 551fd7b9f7bSTejun Heo return; 552324a56e1STejun Heo root = kernfs_root(kn); 553fd7b9f7bSTejun Heo repeat: 55481c173cbSTejun Heo /* 55581c173cbSTejun Heo * Moving/renaming is always done while holding reference. 556adc5e8b5STejun Heo * kn->parent won't change beneath us. 557fd7b9f7bSTejun Heo */ 558adc5e8b5STejun Heo parent = kn->parent; 559fd7b9f7bSTejun Heo 56081c173cbSTejun Heo WARN_ONCE(atomic_read(&kn->active) != KN_DEACTIVATED_BIAS, 56181c173cbSTejun Heo "kernfs_put: %s/%s: released with incorrect active_ref %d\n", 56281c173cbSTejun Heo parent ? parent->name : "", kn->name, atomic_read(&kn->active)); 563fd7b9f7bSTejun Heo 564df23fc39STejun Heo if (kernfs_type(kn) == KERNFS_LINK) 565adc5e8b5STejun Heo kernfs_put(kn->symlink.target_kn); 566dfeb0750STejun Heo 56775287a67SAndrzej Hajda kfree_const(kn->name); 568dfeb0750STejun Heo 569adc5e8b5STejun Heo if (kn->iattr) { 570adc5e8b5STejun Heo if (kn->iattr->ia_secdata) 571adc5e8b5STejun Heo security_release_secctx(kn->iattr->ia_secdata, 572adc5e8b5STejun Heo kn->iattr->ia_secdata_len); 573adc5e8b5STejun Heo simple_xattrs_free(&kn->iattr->xattrs); 5742322392bSTejun Heo } 575adc5e8b5STejun Heo kfree(kn->iattr); 576adc5e8b5STejun Heo ida_simple_remove(&root->ino_ida, kn->ino); 577a797bfc3STejun Heo kmem_cache_free(kernfs_node_cache, kn); 578fd7b9f7bSTejun Heo 579324a56e1STejun Heo kn = parent; 580324a56e1STejun Heo if (kn) { 581adc5e8b5STejun Heo if (atomic_dec_and_test(&kn->count)) 582fd7b9f7bSTejun Heo goto repeat; 583ba7443bcSTejun Heo } else { 584324a56e1STejun Heo /* just released the root kn, free @root too */ 585bc755553STejun Heo ida_destroy(&root->ino_ida); 586ba7443bcSTejun Heo kfree(root); 587ba7443bcSTejun Heo } 588fd7b9f7bSTejun Heo } 589fd7b9f7bSTejun Heo EXPORT_SYMBOL_GPL(kernfs_put); 590fd7b9f7bSTejun Heo 591c637b8acSTejun Heo static int kernfs_dop_revalidate(struct dentry *dentry, unsigned int flags) 592fd7b9f7bSTejun Heo { 593324a56e1STejun Heo struct kernfs_node *kn; 594fd7b9f7bSTejun Heo 595fd7b9f7bSTejun Heo if (flags & LOOKUP_RCU) 596fd7b9f7bSTejun Heo return -ECHILD; 597fd7b9f7bSTejun Heo 59819bbb926STejun Heo /* Always perform fresh lookup for negatives */ 5992b0143b5SDavid Howells if (d_really_is_negative(dentry)) 60019bbb926STejun Heo goto out_bad_unlocked; 60119bbb926STejun Heo 602324a56e1STejun Heo kn = dentry->d_fsdata; 603a797bfc3STejun Heo mutex_lock(&kernfs_mutex); 604fd7b9f7bSTejun Heo 60581c173cbSTejun Heo /* The kernfs node has been deactivated */ 60681c173cbSTejun Heo if (!kernfs_active(kn)) 607fd7b9f7bSTejun Heo goto out_bad; 608fd7b9f7bSTejun Heo 609c637b8acSTejun Heo /* The kernfs node has been moved? */ 610adc5e8b5STejun Heo if (dentry->d_parent->d_fsdata != kn->parent) 611fd7b9f7bSTejun Heo goto out_bad; 612fd7b9f7bSTejun Heo 613c637b8acSTejun Heo /* The kernfs node has been renamed */ 614adc5e8b5STejun Heo if (strcmp(dentry->d_name.name, kn->name) != 0) 615fd7b9f7bSTejun Heo goto out_bad; 616fd7b9f7bSTejun Heo 617c637b8acSTejun Heo /* The kernfs node has been moved to a different namespace */ 618adc5e8b5STejun Heo if (kn->parent && kernfs_ns_enabled(kn->parent) && 619c525aaddSTejun Heo kernfs_info(dentry->d_sb)->ns != kn->ns) 620fd7b9f7bSTejun Heo goto out_bad; 621fd7b9f7bSTejun Heo 622a797bfc3STejun Heo mutex_unlock(&kernfs_mutex); 623fd7b9f7bSTejun Heo return 1; 624fd7b9f7bSTejun Heo out_bad: 625a797bfc3STejun Heo mutex_unlock(&kernfs_mutex); 62619bbb926STejun Heo out_bad_unlocked: 627fd7b9f7bSTejun Heo return 0; 628fd7b9f7bSTejun Heo } 629fd7b9f7bSTejun Heo 630c637b8acSTejun Heo static void kernfs_dop_release(struct dentry *dentry) 631fd7b9f7bSTejun Heo { 632fd7b9f7bSTejun Heo kernfs_put(dentry->d_fsdata); 633fd7b9f7bSTejun Heo } 634fd7b9f7bSTejun Heo 635a797bfc3STejun Heo const struct dentry_operations kernfs_dops = { 636c637b8acSTejun Heo .d_revalidate = kernfs_dop_revalidate, 637c637b8acSTejun Heo .d_release = kernfs_dop_release, 638fd7b9f7bSTejun Heo }; 639fd7b9f7bSTejun Heo 6400c23b225STejun Heo /** 6410c23b225STejun Heo * kernfs_node_from_dentry - determine kernfs_node associated with a dentry 6420c23b225STejun Heo * @dentry: the dentry in question 6430c23b225STejun Heo * 6440c23b225STejun Heo * Return the kernfs_node associated with @dentry. If @dentry is not a 6450c23b225STejun Heo * kernfs one, %NULL is returned. 6460c23b225STejun Heo * 6470c23b225STejun Heo * While the returned kernfs_node will stay accessible as long as @dentry 6480c23b225STejun Heo * is accessible, the returned node can be in any state and the caller is 6490c23b225STejun Heo * fully responsible for determining what's accessible. 6500c23b225STejun Heo */ 6510c23b225STejun Heo struct kernfs_node *kernfs_node_from_dentry(struct dentry *dentry) 6520c23b225STejun Heo { 653f41c5934SLi Zefan if (dentry->d_sb->s_op == &kernfs_sops) 6540c23b225STejun Heo return dentry->d_fsdata; 6550c23b225STejun Heo return NULL; 6560c23b225STejun Heo } 6570c23b225STejun Heo 658db4aad20STejun Heo static struct kernfs_node *__kernfs_new_node(struct kernfs_root *root, 659db4aad20STejun Heo const char *name, umode_t mode, 660db4aad20STejun Heo unsigned flags) 661fd7b9f7bSTejun Heo { 662324a56e1STejun Heo struct kernfs_node *kn; 663bc755553STejun Heo int ret; 664fd7b9f7bSTejun Heo 665dfeb0750STejun Heo name = kstrdup_const(name, GFP_KERNEL); 666fd7b9f7bSTejun Heo if (!name) 667fd7b9f7bSTejun Heo return NULL; 668fd7b9f7bSTejun Heo 669a797bfc3STejun Heo kn = kmem_cache_zalloc(kernfs_node_cache, GFP_KERNEL); 670324a56e1STejun Heo if (!kn) 671fd7b9f7bSTejun Heo goto err_out1; 672fd7b9f7bSTejun Heo 673b2a209ffSVladimir Davydov ret = ida_simple_get(&root->ino_ida, 1, 0, GFP_KERNEL); 674bc755553STejun Heo if (ret < 0) 675fd7b9f7bSTejun Heo goto err_out2; 676adc5e8b5STejun Heo kn->ino = ret; 677fd7b9f7bSTejun Heo 678adc5e8b5STejun Heo atomic_set(&kn->count, 1); 67981c173cbSTejun Heo atomic_set(&kn->active, KN_DEACTIVATED_BIAS); 68035beab06STejun Heo RB_CLEAR_NODE(&kn->rb); 681fd7b9f7bSTejun Heo 682adc5e8b5STejun Heo kn->name = name; 683adc5e8b5STejun Heo kn->mode = mode; 68481c173cbSTejun Heo kn->flags = flags; 685fd7b9f7bSTejun Heo 686324a56e1STejun Heo return kn; 687fd7b9f7bSTejun Heo 688fd7b9f7bSTejun Heo err_out2: 689a797bfc3STejun Heo kmem_cache_free(kernfs_node_cache, kn); 690fd7b9f7bSTejun Heo err_out1: 691dfeb0750STejun Heo kfree_const(name); 692fd7b9f7bSTejun Heo return NULL; 693fd7b9f7bSTejun Heo } 694fd7b9f7bSTejun Heo 695db4aad20STejun Heo struct kernfs_node *kernfs_new_node(struct kernfs_node *parent, 696db4aad20STejun Heo const char *name, umode_t mode, 697db4aad20STejun Heo unsigned flags) 698db4aad20STejun Heo { 699db4aad20STejun Heo struct kernfs_node *kn; 700db4aad20STejun Heo 701db4aad20STejun Heo kn = __kernfs_new_node(kernfs_root(parent), name, mode, flags); 702db4aad20STejun Heo if (kn) { 703db4aad20STejun Heo kernfs_get(parent); 704db4aad20STejun Heo kn->parent = parent; 705db4aad20STejun Heo } 706db4aad20STejun Heo return kn; 707db4aad20STejun Heo } 708db4aad20STejun Heo 709fd7b9f7bSTejun Heo /** 710c637b8acSTejun Heo * kernfs_add_one - add kernfs_node to parent without warning 711324a56e1STejun Heo * @kn: kernfs_node to be added 712fd7b9f7bSTejun Heo * 713db4aad20STejun Heo * The caller must already have initialized @kn->parent. This 714db4aad20STejun Heo * function increments nlink of the parent's inode if @kn is a 715db4aad20STejun Heo * directory and link into the children list of the parent. 716fd7b9f7bSTejun Heo * 717fd7b9f7bSTejun Heo * RETURNS: 718fd7b9f7bSTejun Heo * 0 on success, -EEXIST if entry with the given name already 719fd7b9f7bSTejun Heo * exists. 720fd7b9f7bSTejun Heo */ 721988cd7afSTejun Heo int kernfs_add_one(struct kernfs_node *kn) 722fd7b9f7bSTejun Heo { 723db4aad20STejun Heo struct kernfs_node *parent = kn->parent; 724c525aaddSTejun Heo struct kernfs_iattrs *ps_iattr; 725988cd7afSTejun Heo bool has_ns; 726fd7b9f7bSTejun Heo int ret; 727fd7b9f7bSTejun Heo 728988cd7afSTejun Heo mutex_lock(&kernfs_mutex); 729988cd7afSTejun Heo 730988cd7afSTejun Heo ret = -EINVAL; 731988cd7afSTejun Heo has_ns = kernfs_ns_enabled(parent); 732988cd7afSTejun Heo if (WARN(has_ns != (bool)kn->ns, KERN_WARNING "kernfs: ns %s in '%s' for '%s'\n", 733988cd7afSTejun Heo has_ns ? "required" : "invalid", parent->name, kn->name)) 734988cd7afSTejun Heo goto out_unlock; 735fd7b9f7bSTejun Heo 736df23fc39STejun Heo if (kernfs_type(parent) != KERNFS_DIR) 737988cd7afSTejun Heo goto out_unlock; 738fd7b9f7bSTejun Heo 739988cd7afSTejun Heo ret = -ENOENT; 740ea015218SEric W. Biederman if (parent->flags & KERNFS_EMPTY_DIR) 741ea015218SEric W. Biederman goto out_unlock; 742ea015218SEric W. Biederman 743d35258efSTejun Heo if ((parent->flags & KERNFS_ACTIVATED) && !kernfs_active(parent)) 744988cd7afSTejun Heo goto out_unlock; 745798c75a0SGreg Kroah-Hartman 746c637b8acSTejun Heo kn->hash = kernfs_name_hash(kn->name, kn->ns); 747fd7b9f7bSTejun Heo 748c637b8acSTejun Heo ret = kernfs_link_sibling(kn); 749fd7b9f7bSTejun Heo if (ret) 750988cd7afSTejun Heo goto out_unlock; 751fd7b9f7bSTejun Heo 752fd7b9f7bSTejun Heo /* Update timestamps on the parent */ 753adc5e8b5STejun Heo ps_iattr = parent->iattr; 754fd7b9f7bSTejun Heo if (ps_iattr) { 755fd7b9f7bSTejun Heo struct iattr *ps_iattrs = &ps_iattr->ia_iattr; 756fd7b9f7bSTejun Heo ps_iattrs->ia_ctime = ps_iattrs->ia_mtime = CURRENT_TIME; 757fd7b9f7bSTejun Heo } 758fd7b9f7bSTejun Heo 759d35258efSTejun Heo mutex_unlock(&kernfs_mutex); 760d35258efSTejun Heo 761d35258efSTejun Heo /* 762d35258efSTejun Heo * Activate the new node unless CREATE_DEACTIVATED is requested. 763d35258efSTejun Heo * If not activated here, the kernfs user is responsible for 764d35258efSTejun Heo * activating the node with kernfs_activate(). A node which hasn't 765d35258efSTejun Heo * been activated is not visible to userland and its removal won't 766d35258efSTejun Heo * trigger deactivation. 767d35258efSTejun Heo */ 768d35258efSTejun Heo if (!(kernfs_root(kn)->flags & KERNFS_ROOT_CREATE_DEACTIVATED)) 769d35258efSTejun Heo kernfs_activate(kn); 770d35258efSTejun Heo return 0; 771d35258efSTejun Heo 772988cd7afSTejun Heo out_unlock: 773a797bfc3STejun Heo mutex_unlock(&kernfs_mutex); 774988cd7afSTejun Heo return ret; 775fd7b9f7bSTejun Heo } 776fd7b9f7bSTejun Heo 777fd7b9f7bSTejun Heo /** 778324a56e1STejun Heo * kernfs_find_ns - find kernfs_node with the given name 779324a56e1STejun Heo * @parent: kernfs_node to search under 780fd7b9f7bSTejun Heo * @name: name to look for 781fd7b9f7bSTejun Heo * @ns: the namespace tag to use 782fd7b9f7bSTejun Heo * 783324a56e1STejun Heo * Look for kernfs_node with name @name under @parent. Returns pointer to 784324a56e1STejun Heo * the found kernfs_node on success, %NULL on failure. 785fd7b9f7bSTejun Heo */ 786324a56e1STejun Heo static struct kernfs_node *kernfs_find_ns(struct kernfs_node *parent, 787fd7b9f7bSTejun Heo const unsigned char *name, 788fd7b9f7bSTejun Heo const void *ns) 789fd7b9f7bSTejun Heo { 790adc5e8b5STejun Heo struct rb_node *node = parent->dir.children.rb_node; 791ac9bba03STejun Heo bool has_ns = kernfs_ns_enabled(parent); 792fd7b9f7bSTejun Heo unsigned int hash; 793fd7b9f7bSTejun Heo 794a797bfc3STejun Heo lockdep_assert_held(&kernfs_mutex); 795fd7b9f7bSTejun Heo 796fd7b9f7bSTejun Heo if (has_ns != (bool)ns) { 797c637b8acSTejun Heo WARN(1, KERN_WARNING "kernfs: ns %s in '%s' for '%s'\n", 798adc5e8b5STejun Heo has_ns ? "required" : "invalid", parent->name, name); 799fd7b9f7bSTejun Heo return NULL; 800fd7b9f7bSTejun Heo } 801fd7b9f7bSTejun Heo 802c637b8acSTejun Heo hash = kernfs_name_hash(name, ns); 803fd7b9f7bSTejun Heo while (node) { 804324a56e1STejun Heo struct kernfs_node *kn; 805fd7b9f7bSTejun Heo int result; 806fd7b9f7bSTejun Heo 807324a56e1STejun Heo kn = rb_to_kn(node); 808c637b8acSTejun Heo result = kernfs_name_compare(hash, name, ns, kn); 809fd7b9f7bSTejun Heo if (result < 0) 810fd7b9f7bSTejun Heo node = node->rb_left; 811fd7b9f7bSTejun Heo else if (result > 0) 812fd7b9f7bSTejun Heo node = node->rb_right; 813fd7b9f7bSTejun Heo else 814324a56e1STejun Heo return kn; 815fd7b9f7bSTejun Heo } 816fd7b9f7bSTejun Heo return NULL; 817fd7b9f7bSTejun Heo } 818fd7b9f7bSTejun Heo 819bd96f76aSTejun Heo static struct kernfs_node *kernfs_walk_ns(struct kernfs_node *parent, 820bd96f76aSTejun Heo const unsigned char *path, 821bd96f76aSTejun Heo const void *ns) 822bd96f76aSTejun Heo { 823e56ed358STejun Heo size_t len; 824e56ed358STejun Heo char *p, *name; 825bd96f76aSTejun Heo 826bd96f76aSTejun Heo lockdep_assert_held(&kernfs_mutex); 827bd96f76aSTejun Heo 828e56ed358STejun Heo /* grab kernfs_rename_lock to piggy back on kernfs_pr_cont_buf */ 829e56ed358STejun Heo spin_lock_irq(&kernfs_rename_lock); 830e56ed358STejun Heo 831e56ed358STejun Heo len = strlcpy(kernfs_pr_cont_buf, path, sizeof(kernfs_pr_cont_buf)); 832e56ed358STejun Heo 833e56ed358STejun Heo if (len >= sizeof(kernfs_pr_cont_buf)) { 834e56ed358STejun Heo spin_unlock_irq(&kernfs_rename_lock); 835bd96f76aSTejun Heo return NULL; 836e56ed358STejun Heo } 837e56ed358STejun Heo 838e56ed358STejun Heo p = kernfs_pr_cont_buf; 839bd96f76aSTejun Heo 840bd96f76aSTejun Heo while ((name = strsep(&p, "/")) && parent) { 841bd96f76aSTejun Heo if (*name == '\0') 842bd96f76aSTejun Heo continue; 843bd96f76aSTejun Heo parent = kernfs_find_ns(parent, name, ns); 844bd96f76aSTejun Heo } 845bd96f76aSTejun Heo 846e56ed358STejun Heo spin_unlock_irq(&kernfs_rename_lock); 847e56ed358STejun Heo 848bd96f76aSTejun Heo return parent; 849bd96f76aSTejun Heo } 850bd96f76aSTejun Heo 851fd7b9f7bSTejun Heo /** 852324a56e1STejun Heo * kernfs_find_and_get_ns - find and get kernfs_node with the given name 853324a56e1STejun Heo * @parent: kernfs_node to search under 854fd7b9f7bSTejun Heo * @name: name to look for 855fd7b9f7bSTejun Heo * @ns: the namespace tag to use 856fd7b9f7bSTejun Heo * 857324a56e1STejun Heo * Look for kernfs_node with name @name under @parent and get a reference 858fd7b9f7bSTejun Heo * if found. This function may sleep and returns pointer to the found 859324a56e1STejun Heo * kernfs_node on success, %NULL on failure. 860fd7b9f7bSTejun Heo */ 861324a56e1STejun Heo struct kernfs_node *kernfs_find_and_get_ns(struct kernfs_node *parent, 862fd7b9f7bSTejun Heo const char *name, const void *ns) 863fd7b9f7bSTejun Heo { 864324a56e1STejun Heo struct kernfs_node *kn; 865fd7b9f7bSTejun Heo 866a797bfc3STejun Heo mutex_lock(&kernfs_mutex); 867324a56e1STejun Heo kn = kernfs_find_ns(parent, name, ns); 868324a56e1STejun Heo kernfs_get(kn); 869a797bfc3STejun Heo mutex_unlock(&kernfs_mutex); 870fd7b9f7bSTejun Heo 871324a56e1STejun Heo return kn; 872fd7b9f7bSTejun Heo } 873fd7b9f7bSTejun Heo EXPORT_SYMBOL_GPL(kernfs_find_and_get_ns); 874fd7b9f7bSTejun Heo 875fd7b9f7bSTejun Heo /** 876bd96f76aSTejun Heo * kernfs_walk_and_get_ns - find and get kernfs_node with the given path 877bd96f76aSTejun Heo * @parent: kernfs_node to search under 878bd96f76aSTejun Heo * @path: path to look for 879bd96f76aSTejun Heo * @ns: the namespace tag to use 880bd96f76aSTejun Heo * 881bd96f76aSTejun Heo * Look for kernfs_node with path @path under @parent and get a reference 882bd96f76aSTejun Heo * if found. This function may sleep and returns pointer to the found 883bd96f76aSTejun Heo * kernfs_node on success, %NULL on failure. 884bd96f76aSTejun Heo */ 885bd96f76aSTejun Heo struct kernfs_node *kernfs_walk_and_get_ns(struct kernfs_node *parent, 886bd96f76aSTejun Heo const char *path, const void *ns) 887bd96f76aSTejun Heo { 888bd96f76aSTejun Heo struct kernfs_node *kn; 889bd96f76aSTejun Heo 890bd96f76aSTejun Heo mutex_lock(&kernfs_mutex); 891bd96f76aSTejun Heo kn = kernfs_walk_ns(parent, path, ns); 892bd96f76aSTejun Heo kernfs_get(kn); 893bd96f76aSTejun Heo mutex_unlock(&kernfs_mutex); 894bd96f76aSTejun Heo 895bd96f76aSTejun Heo return kn; 896bd96f76aSTejun Heo } 897bd96f76aSTejun Heo 898bd96f76aSTejun Heo /** 899ba7443bcSTejun Heo * kernfs_create_root - create a new kernfs hierarchy 90090c07c89STejun Heo * @scops: optional syscall operations for the hierarchy 901d35258efSTejun Heo * @flags: KERNFS_ROOT_* flags 902ba7443bcSTejun Heo * @priv: opaque data associated with the new directory 903ba7443bcSTejun Heo * 904ba7443bcSTejun Heo * Returns the root of the new hierarchy on success, ERR_PTR() value on 905ba7443bcSTejun Heo * failure. 906ba7443bcSTejun Heo */ 90790c07c89STejun Heo struct kernfs_root *kernfs_create_root(struct kernfs_syscall_ops *scops, 908d35258efSTejun Heo unsigned int flags, void *priv) 909ba7443bcSTejun Heo { 910ba7443bcSTejun Heo struct kernfs_root *root; 911324a56e1STejun Heo struct kernfs_node *kn; 912ba7443bcSTejun Heo 913ba7443bcSTejun Heo root = kzalloc(sizeof(*root), GFP_KERNEL); 914ba7443bcSTejun Heo if (!root) 915ba7443bcSTejun Heo return ERR_PTR(-ENOMEM); 916ba7443bcSTejun Heo 917bc755553STejun Heo ida_init(&root->ino_ida); 9187d568a83STejun Heo INIT_LIST_HEAD(&root->supers); 919bc755553STejun Heo 920db4aad20STejun Heo kn = __kernfs_new_node(root, "", S_IFDIR | S_IRUGO | S_IXUGO, 921db4aad20STejun Heo KERNFS_DIR); 922324a56e1STejun Heo if (!kn) { 923bc755553STejun Heo ida_destroy(&root->ino_ida); 924ba7443bcSTejun Heo kfree(root); 925ba7443bcSTejun Heo return ERR_PTR(-ENOMEM); 926ba7443bcSTejun Heo } 927ba7443bcSTejun Heo 928324a56e1STejun Heo kn->priv = priv; 929adc5e8b5STejun Heo kn->dir.root = root; 930ba7443bcSTejun Heo 93190c07c89STejun Heo root->syscall_ops = scops; 932d35258efSTejun Heo root->flags = flags; 933324a56e1STejun Heo root->kn = kn; 934abd54f02STejun Heo init_waitqueue_head(&root->deactivate_waitq); 935ba7443bcSTejun Heo 936d35258efSTejun Heo if (!(root->flags & KERNFS_ROOT_CREATE_DEACTIVATED)) 937d35258efSTejun Heo kernfs_activate(kn); 938d35258efSTejun Heo 939ba7443bcSTejun Heo return root; 940ba7443bcSTejun Heo } 941ba7443bcSTejun Heo 942ba7443bcSTejun Heo /** 943ba7443bcSTejun Heo * kernfs_destroy_root - destroy a kernfs hierarchy 944ba7443bcSTejun Heo * @root: root of the hierarchy to destroy 945ba7443bcSTejun Heo * 946ba7443bcSTejun Heo * Destroy the hierarchy anchored at @root by removing all existing 947ba7443bcSTejun Heo * directories and destroying @root. 948ba7443bcSTejun Heo */ 949ba7443bcSTejun Heo void kernfs_destroy_root(struct kernfs_root *root) 950ba7443bcSTejun Heo { 951324a56e1STejun Heo kernfs_remove(root->kn); /* will also free @root */ 952ba7443bcSTejun Heo } 953ba7443bcSTejun Heo 954ba7443bcSTejun Heo /** 955fd7b9f7bSTejun Heo * kernfs_create_dir_ns - create a directory 956fd7b9f7bSTejun Heo * @parent: parent in which to create a new directory 957fd7b9f7bSTejun Heo * @name: name of the new directory 958bb8b9d09STejun Heo * @mode: mode of the new directory 959fd7b9f7bSTejun Heo * @priv: opaque data associated with the new directory 960fd7b9f7bSTejun Heo * @ns: optional namespace tag of the directory 961fd7b9f7bSTejun Heo * 962fd7b9f7bSTejun Heo * Returns the created node on success, ERR_PTR() value on failure. 963fd7b9f7bSTejun Heo */ 964324a56e1STejun Heo struct kernfs_node *kernfs_create_dir_ns(struct kernfs_node *parent, 965bb8b9d09STejun Heo const char *name, umode_t mode, 966bb8b9d09STejun Heo void *priv, const void *ns) 967fd7b9f7bSTejun Heo { 968324a56e1STejun Heo struct kernfs_node *kn; 969fd7b9f7bSTejun Heo int rc; 970fd7b9f7bSTejun Heo 971fd7b9f7bSTejun Heo /* allocate */ 972db4aad20STejun Heo kn = kernfs_new_node(parent, name, mode | S_IFDIR, KERNFS_DIR); 973324a56e1STejun Heo if (!kn) 974fd7b9f7bSTejun Heo return ERR_PTR(-ENOMEM); 975fd7b9f7bSTejun Heo 976adc5e8b5STejun Heo kn->dir.root = parent->dir.root; 977adc5e8b5STejun Heo kn->ns = ns; 978324a56e1STejun Heo kn->priv = priv; 979fd7b9f7bSTejun Heo 980fd7b9f7bSTejun Heo /* link in */ 981988cd7afSTejun Heo rc = kernfs_add_one(kn); 982fd7b9f7bSTejun Heo if (!rc) 983324a56e1STejun Heo return kn; 984fd7b9f7bSTejun Heo 985324a56e1STejun Heo kernfs_put(kn); 986fd7b9f7bSTejun Heo return ERR_PTR(rc); 987fd7b9f7bSTejun Heo } 988fd7b9f7bSTejun Heo 989ea015218SEric W. Biederman /** 990ea015218SEric W. Biederman * kernfs_create_empty_dir - create an always empty directory 991ea015218SEric W. Biederman * @parent: parent in which to create a new directory 992ea015218SEric W. Biederman * @name: name of the new directory 993ea015218SEric W. Biederman * 994ea015218SEric W. Biederman * Returns the created node on success, ERR_PTR() value on failure. 995ea015218SEric W. Biederman */ 996ea015218SEric W. Biederman struct kernfs_node *kernfs_create_empty_dir(struct kernfs_node *parent, 997ea015218SEric W. Biederman const char *name) 998ea015218SEric W. Biederman { 999ea015218SEric W. Biederman struct kernfs_node *kn; 1000ea015218SEric W. Biederman int rc; 1001ea015218SEric W. Biederman 1002ea015218SEric W. Biederman /* allocate */ 1003ea015218SEric W. Biederman kn = kernfs_new_node(parent, name, S_IRUGO|S_IXUGO|S_IFDIR, KERNFS_DIR); 1004ea015218SEric W. Biederman if (!kn) 1005ea015218SEric W. Biederman return ERR_PTR(-ENOMEM); 1006ea015218SEric W. Biederman 1007ea015218SEric W. Biederman kn->flags |= KERNFS_EMPTY_DIR; 1008ea015218SEric W. Biederman kn->dir.root = parent->dir.root; 1009ea015218SEric W. Biederman kn->ns = NULL; 1010ea015218SEric W. Biederman kn->priv = NULL; 1011ea015218SEric W. Biederman 1012ea015218SEric W. Biederman /* link in */ 1013ea015218SEric W. Biederman rc = kernfs_add_one(kn); 1014ea015218SEric W. Biederman if (!rc) 1015ea015218SEric W. Biederman return kn; 1016ea015218SEric W. Biederman 1017ea015218SEric W. Biederman kernfs_put(kn); 1018ea015218SEric W. Biederman return ERR_PTR(rc); 1019ea015218SEric W. Biederman } 1020ea015218SEric W. Biederman 1021c637b8acSTejun Heo static struct dentry *kernfs_iop_lookup(struct inode *dir, 1022c637b8acSTejun Heo struct dentry *dentry, 1023fd7b9f7bSTejun Heo unsigned int flags) 1024fd7b9f7bSTejun Heo { 102519bbb926STejun Heo struct dentry *ret; 1026324a56e1STejun Heo struct kernfs_node *parent = dentry->d_parent->d_fsdata; 1027324a56e1STejun Heo struct kernfs_node *kn; 1028fd7b9f7bSTejun Heo struct inode *inode; 1029fd7b9f7bSTejun Heo const void *ns = NULL; 1030fd7b9f7bSTejun Heo 1031a797bfc3STejun Heo mutex_lock(&kernfs_mutex); 1032fd7b9f7bSTejun Heo 1033324a56e1STejun Heo if (kernfs_ns_enabled(parent)) 1034c525aaddSTejun Heo ns = kernfs_info(dir->i_sb)->ns; 1035fd7b9f7bSTejun Heo 1036324a56e1STejun Heo kn = kernfs_find_ns(parent, dentry->d_name.name, ns); 1037fd7b9f7bSTejun Heo 1038fd7b9f7bSTejun Heo /* no such entry */ 1039b9c9dad0STejun Heo if (!kn || !kernfs_active(kn)) { 104019bbb926STejun Heo ret = NULL; 1041fd7b9f7bSTejun Heo goto out_unlock; 1042fd7b9f7bSTejun Heo } 1043324a56e1STejun Heo kernfs_get(kn); 1044324a56e1STejun Heo dentry->d_fsdata = kn; 1045fd7b9f7bSTejun Heo 1046fd7b9f7bSTejun Heo /* attach dentry and inode */ 1047c637b8acSTejun Heo inode = kernfs_get_inode(dir->i_sb, kn); 1048fd7b9f7bSTejun Heo if (!inode) { 1049fd7b9f7bSTejun Heo ret = ERR_PTR(-ENOMEM); 1050fd7b9f7bSTejun Heo goto out_unlock; 1051fd7b9f7bSTejun Heo } 1052fd7b9f7bSTejun Heo 1053fd7b9f7bSTejun Heo /* instantiate and hash dentry */ 105441d28bcaSAl Viro ret = d_splice_alias(inode, dentry); 1055fd7b9f7bSTejun Heo out_unlock: 1056a797bfc3STejun Heo mutex_unlock(&kernfs_mutex); 1057fd7b9f7bSTejun Heo return ret; 1058fd7b9f7bSTejun Heo } 1059fd7b9f7bSTejun Heo 106080b9bbefSTejun Heo static int kernfs_iop_mkdir(struct inode *dir, struct dentry *dentry, 106180b9bbefSTejun Heo umode_t mode) 106280b9bbefSTejun Heo { 106380b9bbefSTejun Heo struct kernfs_node *parent = dir->i_private; 106490c07c89STejun Heo struct kernfs_syscall_ops *scops = kernfs_root(parent)->syscall_ops; 106507c7530dSTejun Heo int ret; 106680b9bbefSTejun Heo 106790c07c89STejun Heo if (!scops || !scops->mkdir) 106880b9bbefSTejun Heo return -EPERM; 106980b9bbefSTejun Heo 107007c7530dSTejun Heo if (!kernfs_get_active(parent)) 107107c7530dSTejun Heo return -ENODEV; 107207c7530dSTejun Heo 107390c07c89STejun Heo ret = scops->mkdir(parent, dentry->d_name.name, mode); 107407c7530dSTejun Heo 107507c7530dSTejun Heo kernfs_put_active(parent); 107607c7530dSTejun Heo return ret; 107780b9bbefSTejun Heo } 107880b9bbefSTejun Heo 107980b9bbefSTejun Heo static int kernfs_iop_rmdir(struct inode *dir, struct dentry *dentry) 108080b9bbefSTejun Heo { 108180b9bbefSTejun Heo struct kernfs_node *kn = dentry->d_fsdata; 108290c07c89STejun Heo struct kernfs_syscall_ops *scops = kernfs_root(kn)->syscall_ops; 108307c7530dSTejun Heo int ret; 108480b9bbefSTejun Heo 108590c07c89STejun Heo if (!scops || !scops->rmdir) 108680b9bbefSTejun Heo return -EPERM; 108780b9bbefSTejun Heo 108807c7530dSTejun Heo if (!kernfs_get_active(kn)) 108907c7530dSTejun Heo return -ENODEV; 109007c7530dSTejun Heo 109190c07c89STejun Heo ret = scops->rmdir(kn); 109207c7530dSTejun Heo 109307c7530dSTejun Heo kernfs_put_active(kn); 109407c7530dSTejun Heo return ret; 109580b9bbefSTejun Heo } 109680b9bbefSTejun Heo 109780b9bbefSTejun Heo static int kernfs_iop_rename(struct inode *old_dir, struct dentry *old_dentry, 109880b9bbefSTejun Heo struct inode *new_dir, struct dentry *new_dentry) 109980b9bbefSTejun Heo { 110080b9bbefSTejun Heo struct kernfs_node *kn = old_dentry->d_fsdata; 110180b9bbefSTejun Heo struct kernfs_node *new_parent = new_dir->i_private; 110290c07c89STejun Heo struct kernfs_syscall_ops *scops = kernfs_root(kn)->syscall_ops; 110307c7530dSTejun Heo int ret; 110480b9bbefSTejun Heo 110590c07c89STejun Heo if (!scops || !scops->rename) 110680b9bbefSTejun Heo return -EPERM; 110780b9bbefSTejun Heo 110807c7530dSTejun Heo if (!kernfs_get_active(kn)) 110907c7530dSTejun Heo return -ENODEV; 111007c7530dSTejun Heo 111107c7530dSTejun Heo if (!kernfs_get_active(new_parent)) { 111207c7530dSTejun Heo kernfs_put_active(kn); 111307c7530dSTejun Heo return -ENODEV; 111407c7530dSTejun Heo } 111507c7530dSTejun Heo 111690c07c89STejun Heo ret = scops->rename(kn, new_parent, new_dentry->d_name.name); 111707c7530dSTejun Heo 111807c7530dSTejun Heo kernfs_put_active(new_parent); 111907c7530dSTejun Heo kernfs_put_active(kn); 112007c7530dSTejun Heo return ret; 112180b9bbefSTejun Heo } 112280b9bbefSTejun Heo 1123a797bfc3STejun Heo const struct inode_operations kernfs_dir_iops = { 1124c637b8acSTejun Heo .lookup = kernfs_iop_lookup, 1125c637b8acSTejun Heo .permission = kernfs_iop_permission, 1126c637b8acSTejun Heo .setattr = kernfs_iop_setattr, 1127c637b8acSTejun Heo .getattr = kernfs_iop_getattr, 1128c637b8acSTejun Heo .setxattr = kernfs_iop_setxattr, 1129c637b8acSTejun Heo .removexattr = kernfs_iop_removexattr, 1130c637b8acSTejun Heo .getxattr = kernfs_iop_getxattr, 1131c637b8acSTejun Heo .listxattr = kernfs_iop_listxattr, 113280b9bbefSTejun Heo 113380b9bbefSTejun Heo .mkdir = kernfs_iop_mkdir, 113480b9bbefSTejun Heo .rmdir = kernfs_iop_rmdir, 113580b9bbefSTejun Heo .rename = kernfs_iop_rename, 1136fd7b9f7bSTejun Heo }; 1137fd7b9f7bSTejun Heo 1138c637b8acSTejun Heo static struct kernfs_node *kernfs_leftmost_descendant(struct kernfs_node *pos) 1139fd7b9f7bSTejun Heo { 1140324a56e1STejun Heo struct kernfs_node *last; 1141fd7b9f7bSTejun Heo 1142fd7b9f7bSTejun Heo while (true) { 1143fd7b9f7bSTejun Heo struct rb_node *rbn; 1144fd7b9f7bSTejun Heo 1145fd7b9f7bSTejun Heo last = pos; 1146fd7b9f7bSTejun Heo 1147df23fc39STejun Heo if (kernfs_type(pos) != KERNFS_DIR) 1148fd7b9f7bSTejun Heo break; 1149fd7b9f7bSTejun Heo 1150adc5e8b5STejun Heo rbn = rb_first(&pos->dir.children); 1151fd7b9f7bSTejun Heo if (!rbn) 1152fd7b9f7bSTejun Heo break; 1153fd7b9f7bSTejun Heo 1154324a56e1STejun Heo pos = rb_to_kn(rbn); 1155fd7b9f7bSTejun Heo } 1156fd7b9f7bSTejun Heo 1157fd7b9f7bSTejun Heo return last; 1158fd7b9f7bSTejun Heo } 1159fd7b9f7bSTejun Heo 1160fd7b9f7bSTejun Heo /** 1161c637b8acSTejun Heo * kernfs_next_descendant_post - find the next descendant for post-order walk 1162fd7b9f7bSTejun Heo * @pos: the current position (%NULL to initiate traversal) 1163324a56e1STejun Heo * @root: kernfs_node whose descendants to walk 1164fd7b9f7bSTejun Heo * 1165fd7b9f7bSTejun Heo * Find the next descendant to visit for post-order traversal of @root's 1166fd7b9f7bSTejun Heo * descendants. @root is included in the iteration and the last node to be 1167fd7b9f7bSTejun Heo * visited. 1168fd7b9f7bSTejun Heo */ 1169c637b8acSTejun Heo static struct kernfs_node *kernfs_next_descendant_post(struct kernfs_node *pos, 1170324a56e1STejun Heo struct kernfs_node *root) 1171fd7b9f7bSTejun Heo { 1172fd7b9f7bSTejun Heo struct rb_node *rbn; 1173fd7b9f7bSTejun Heo 1174a797bfc3STejun Heo lockdep_assert_held(&kernfs_mutex); 1175fd7b9f7bSTejun Heo 1176fd7b9f7bSTejun Heo /* if first iteration, visit leftmost descendant which may be root */ 1177fd7b9f7bSTejun Heo if (!pos) 1178c637b8acSTejun Heo return kernfs_leftmost_descendant(root); 1179fd7b9f7bSTejun Heo 1180fd7b9f7bSTejun Heo /* if we visited @root, we're done */ 1181fd7b9f7bSTejun Heo if (pos == root) 1182fd7b9f7bSTejun Heo return NULL; 1183fd7b9f7bSTejun Heo 1184fd7b9f7bSTejun Heo /* if there's an unvisited sibling, visit its leftmost descendant */ 1185adc5e8b5STejun Heo rbn = rb_next(&pos->rb); 1186fd7b9f7bSTejun Heo if (rbn) 1187c637b8acSTejun Heo return kernfs_leftmost_descendant(rb_to_kn(rbn)); 1188fd7b9f7bSTejun Heo 1189fd7b9f7bSTejun Heo /* no sibling left, visit parent */ 1190adc5e8b5STejun Heo return pos->parent; 1191fd7b9f7bSTejun Heo } 1192fd7b9f7bSTejun Heo 1193d35258efSTejun Heo /** 1194d35258efSTejun Heo * kernfs_activate - activate a node which started deactivated 1195d35258efSTejun Heo * @kn: kernfs_node whose subtree is to be activated 1196d35258efSTejun Heo * 1197d35258efSTejun Heo * If the root has KERNFS_ROOT_CREATE_DEACTIVATED set, a newly created node 1198d35258efSTejun Heo * needs to be explicitly activated. A node which hasn't been activated 1199d35258efSTejun Heo * isn't visible to userland and deactivation is skipped during its 1200d35258efSTejun Heo * removal. This is useful to construct atomic init sequences where 1201d35258efSTejun Heo * creation of multiple nodes should either succeed or fail atomically. 1202d35258efSTejun Heo * 1203d35258efSTejun Heo * The caller is responsible for ensuring that this function is not called 1204d35258efSTejun Heo * after kernfs_remove*() is invoked on @kn. 1205d35258efSTejun Heo */ 1206d35258efSTejun Heo void kernfs_activate(struct kernfs_node *kn) 1207d35258efSTejun Heo { 1208d35258efSTejun Heo struct kernfs_node *pos; 1209d35258efSTejun Heo 1210d35258efSTejun Heo mutex_lock(&kernfs_mutex); 1211d35258efSTejun Heo 1212d35258efSTejun Heo pos = NULL; 1213d35258efSTejun Heo while ((pos = kernfs_next_descendant_post(pos, kn))) { 1214d35258efSTejun Heo if (!pos || (pos->flags & KERNFS_ACTIVATED)) 1215d35258efSTejun Heo continue; 1216d35258efSTejun Heo 1217d35258efSTejun Heo WARN_ON_ONCE(pos->parent && RB_EMPTY_NODE(&pos->rb)); 1218d35258efSTejun Heo WARN_ON_ONCE(atomic_read(&pos->active) != KN_DEACTIVATED_BIAS); 1219d35258efSTejun Heo 1220d35258efSTejun Heo atomic_sub(KN_DEACTIVATED_BIAS, &pos->active); 1221d35258efSTejun Heo pos->flags |= KERNFS_ACTIVATED; 1222d35258efSTejun Heo } 1223d35258efSTejun Heo 1224d35258efSTejun Heo mutex_unlock(&kernfs_mutex); 1225d35258efSTejun Heo } 1226d35258efSTejun Heo 1227988cd7afSTejun Heo static void __kernfs_remove(struct kernfs_node *kn) 1228fd7b9f7bSTejun Heo { 122935beab06STejun Heo struct kernfs_node *pos; 123035beab06STejun Heo 123135beab06STejun Heo lockdep_assert_held(&kernfs_mutex); 1232fd7b9f7bSTejun Heo 12336b0afc2aSTejun Heo /* 12346b0afc2aSTejun Heo * Short-circuit if non-root @kn has already finished removal. 12356b0afc2aSTejun Heo * This is for kernfs_remove_self() which plays with active ref 12366b0afc2aSTejun Heo * after removal. 12376b0afc2aSTejun Heo */ 12386b0afc2aSTejun Heo if (!kn || (kn->parent && RB_EMPTY_NODE(&kn->rb))) 1239ce9b499cSGreg Kroah-Hartman return; 1240ce9b499cSGreg Kroah-Hartman 1241c637b8acSTejun Heo pr_debug("kernfs %s: removing\n", kn->name); 1242fd7b9f7bSTejun Heo 124381c173cbSTejun Heo /* prevent any new usage under @kn by deactivating all nodes */ 124435beab06STejun Heo pos = NULL; 124535beab06STejun Heo while ((pos = kernfs_next_descendant_post(pos, kn))) 124681c173cbSTejun Heo if (kernfs_active(pos)) 124781c173cbSTejun Heo atomic_add(KN_DEACTIVATED_BIAS, &pos->active); 124835beab06STejun Heo 124935beab06STejun Heo /* deactivate and unlink the subtree node-by-node */ 1250fd7b9f7bSTejun Heo do { 125135beab06STejun Heo pos = kernfs_leftmost_descendant(kn); 125235beab06STejun Heo 125335beab06STejun Heo /* 125481c173cbSTejun Heo * kernfs_drain() drops kernfs_mutex temporarily and @pos's 125581c173cbSTejun Heo * base ref could have been put by someone else by the time 125681c173cbSTejun Heo * the function returns. Make sure it doesn't go away 125781c173cbSTejun Heo * underneath us. 125835beab06STejun Heo */ 125935beab06STejun Heo kernfs_get(pos); 126035beab06STejun Heo 1261d35258efSTejun Heo /* 1262d35258efSTejun Heo * Drain iff @kn was activated. This avoids draining and 1263d35258efSTejun Heo * its lockdep annotations for nodes which have never been 1264d35258efSTejun Heo * activated and allows embedding kernfs_remove() in create 1265d35258efSTejun Heo * error paths without worrying about draining. 1266d35258efSTejun Heo */ 1267d35258efSTejun Heo if (kn->flags & KERNFS_ACTIVATED) 126881c173cbSTejun Heo kernfs_drain(pos); 1269d35258efSTejun Heo else 1270d35258efSTejun Heo WARN_ON_ONCE(atomic_read(&kn->active) != KN_DEACTIVATED_BIAS); 127135beab06STejun Heo 127235beab06STejun Heo /* 127335beab06STejun Heo * kernfs_unlink_sibling() succeeds once per node. Use it 127435beab06STejun Heo * to decide who's responsible for cleanups. 127535beab06STejun Heo */ 127635beab06STejun Heo if (!pos->parent || kernfs_unlink_sibling(pos)) { 127735beab06STejun Heo struct kernfs_iattrs *ps_iattr = 127835beab06STejun Heo pos->parent ? pos->parent->iattr : NULL; 127935beab06STejun Heo 128035beab06STejun Heo /* update timestamps on the parent */ 128135beab06STejun Heo if (ps_iattr) { 128235beab06STejun Heo ps_iattr->ia_iattr.ia_ctime = CURRENT_TIME; 128335beab06STejun Heo ps_iattr->ia_iattr.ia_mtime = CURRENT_TIME; 128435beab06STejun Heo } 128535beab06STejun Heo 1286988cd7afSTejun Heo kernfs_put(pos); 128735beab06STejun Heo } 128835beab06STejun Heo 128935beab06STejun Heo kernfs_put(pos); 129035beab06STejun Heo } while (pos != kn); 1291fd7b9f7bSTejun Heo } 1292fd7b9f7bSTejun Heo 1293fd7b9f7bSTejun Heo /** 1294324a56e1STejun Heo * kernfs_remove - remove a kernfs_node recursively 1295324a56e1STejun Heo * @kn: the kernfs_node to remove 1296fd7b9f7bSTejun Heo * 1297324a56e1STejun Heo * Remove @kn along with all its subdirectories and files. 1298fd7b9f7bSTejun Heo */ 1299324a56e1STejun Heo void kernfs_remove(struct kernfs_node *kn) 1300fd7b9f7bSTejun Heo { 1301988cd7afSTejun Heo mutex_lock(&kernfs_mutex); 1302988cd7afSTejun Heo __kernfs_remove(kn); 1303988cd7afSTejun Heo mutex_unlock(&kernfs_mutex); 1304fd7b9f7bSTejun Heo } 1305fd7b9f7bSTejun Heo 1306fd7b9f7bSTejun Heo /** 13076b0afc2aSTejun Heo * kernfs_break_active_protection - break out of active protection 13086b0afc2aSTejun Heo * @kn: the self kernfs_node 13096b0afc2aSTejun Heo * 13106b0afc2aSTejun Heo * The caller must be running off of a kernfs operation which is invoked 13116b0afc2aSTejun Heo * with an active reference - e.g. one of kernfs_ops. Each invocation of 13126b0afc2aSTejun Heo * this function must also be matched with an invocation of 13136b0afc2aSTejun Heo * kernfs_unbreak_active_protection(). 13146b0afc2aSTejun Heo * 13156b0afc2aSTejun Heo * This function releases the active reference of @kn the caller is 13166b0afc2aSTejun Heo * holding. Once this function is called, @kn may be removed at any point 13176b0afc2aSTejun Heo * and the caller is solely responsible for ensuring that the objects it 13186b0afc2aSTejun Heo * dereferences are accessible. 13196b0afc2aSTejun Heo */ 13206b0afc2aSTejun Heo void kernfs_break_active_protection(struct kernfs_node *kn) 13216b0afc2aSTejun Heo { 13226b0afc2aSTejun Heo /* 13236b0afc2aSTejun Heo * Take out ourself out of the active ref dependency chain. If 13246b0afc2aSTejun Heo * we're called without an active ref, lockdep will complain. 13256b0afc2aSTejun Heo */ 13266b0afc2aSTejun Heo kernfs_put_active(kn); 13276b0afc2aSTejun Heo } 13286b0afc2aSTejun Heo 13296b0afc2aSTejun Heo /** 13306b0afc2aSTejun Heo * kernfs_unbreak_active_protection - undo kernfs_break_active_protection() 13316b0afc2aSTejun Heo * @kn: the self kernfs_node 13326b0afc2aSTejun Heo * 13336b0afc2aSTejun Heo * If kernfs_break_active_protection() was called, this function must be 13346b0afc2aSTejun Heo * invoked before finishing the kernfs operation. Note that while this 13356b0afc2aSTejun Heo * function restores the active reference, it doesn't and can't actually 13366b0afc2aSTejun Heo * restore the active protection - @kn may already or be in the process of 13376b0afc2aSTejun Heo * being removed. Once kernfs_break_active_protection() is invoked, that 13386b0afc2aSTejun Heo * protection is irreversibly gone for the kernfs operation instance. 13396b0afc2aSTejun Heo * 13406b0afc2aSTejun Heo * While this function may be called at any point after 13416b0afc2aSTejun Heo * kernfs_break_active_protection() is invoked, its most useful location 13426b0afc2aSTejun Heo * would be right before the enclosing kernfs operation returns. 13436b0afc2aSTejun Heo */ 13446b0afc2aSTejun Heo void kernfs_unbreak_active_protection(struct kernfs_node *kn) 13456b0afc2aSTejun Heo { 13466b0afc2aSTejun Heo /* 13476b0afc2aSTejun Heo * @kn->active could be in any state; however, the increment we do 13486b0afc2aSTejun Heo * here will be undone as soon as the enclosing kernfs operation 13496b0afc2aSTejun Heo * finishes and this temporary bump can't break anything. If @kn 13506b0afc2aSTejun Heo * is alive, nothing changes. If @kn is being deactivated, the 13516b0afc2aSTejun Heo * soon-to-follow put will either finish deactivation or restore 13526b0afc2aSTejun Heo * deactivated state. If @kn is already removed, the temporary 13536b0afc2aSTejun Heo * bump is guaranteed to be gone before @kn is released. 13546b0afc2aSTejun Heo */ 13556b0afc2aSTejun Heo atomic_inc(&kn->active); 13566b0afc2aSTejun Heo if (kernfs_lockdep(kn)) 13576b0afc2aSTejun Heo rwsem_acquire(&kn->dep_map, 0, 1, _RET_IP_); 13586b0afc2aSTejun Heo } 13596b0afc2aSTejun Heo 13606b0afc2aSTejun Heo /** 13616b0afc2aSTejun Heo * kernfs_remove_self - remove a kernfs_node from its own method 13626b0afc2aSTejun Heo * @kn: the self kernfs_node to remove 13636b0afc2aSTejun Heo * 13646b0afc2aSTejun Heo * The caller must be running off of a kernfs operation which is invoked 13656b0afc2aSTejun Heo * with an active reference - e.g. one of kernfs_ops. This can be used to 13666b0afc2aSTejun Heo * implement a file operation which deletes itself. 13676b0afc2aSTejun Heo * 13686b0afc2aSTejun Heo * For example, the "delete" file for a sysfs device directory can be 13696b0afc2aSTejun Heo * implemented by invoking kernfs_remove_self() on the "delete" file 13706b0afc2aSTejun Heo * itself. This function breaks the circular dependency of trying to 13716b0afc2aSTejun Heo * deactivate self while holding an active ref itself. It isn't necessary 13726b0afc2aSTejun Heo * to modify the usual removal path to use kernfs_remove_self(). The 13736b0afc2aSTejun Heo * "delete" implementation can simply invoke kernfs_remove_self() on self 13746b0afc2aSTejun Heo * before proceeding with the usual removal path. kernfs will ignore later 13756b0afc2aSTejun Heo * kernfs_remove() on self. 13766b0afc2aSTejun Heo * 13776b0afc2aSTejun Heo * kernfs_remove_self() can be called multiple times concurrently on the 13786b0afc2aSTejun Heo * same kernfs_node. Only the first one actually performs removal and 13796b0afc2aSTejun Heo * returns %true. All others will wait until the kernfs operation which 13806b0afc2aSTejun Heo * won self-removal finishes and return %false. Note that the losers wait 13816b0afc2aSTejun Heo * for the completion of not only the winning kernfs_remove_self() but also 13826b0afc2aSTejun Heo * the whole kernfs_ops which won the arbitration. This can be used to 13836b0afc2aSTejun Heo * guarantee, for example, all concurrent writes to a "delete" file to 13846b0afc2aSTejun Heo * finish only after the whole operation is complete. 13856b0afc2aSTejun Heo */ 13866b0afc2aSTejun Heo bool kernfs_remove_self(struct kernfs_node *kn) 13876b0afc2aSTejun Heo { 13886b0afc2aSTejun Heo bool ret; 13896b0afc2aSTejun Heo 13906b0afc2aSTejun Heo mutex_lock(&kernfs_mutex); 13916b0afc2aSTejun Heo kernfs_break_active_protection(kn); 13926b0afc2aSTejun Heo 13936b0afc2aSTejun Heo /* 13946b0afc2aSTejun Heo * SUICIDAL is used to arbitrate among competing invocations. Only 13956b0afc2aSTejun Heo * the first one will actually perform removal. When the removal 13966b0afc2aSTejun Heo * is complete, SUICIDED is set and the active ref is restored 13976b0afc2aSTejun Heo * while holding kernfs_mutex. The ones which lost arbitration 13986b0afc2aSTejun Heo * waits for SUICDED && drained which can happen only after the 13996b0afc2aSTejun Heo * enclosing kernfs operation which executed the winning instance 14006b0afc2aSTejun Heo * of kernfs_remove_self() finished. 14016b0afc2aSTejun Heo */ 14026b0afc2aSTejun Heo if (!(kn->flags & KERNFS_SUICIDAL)) { 14036b0afc2aSTejun Heo kn->flags |= KERNFS_SUICIDAL; 14046b0afc2aSTejun Heo __kernfs_remove(kn); 14056b0afc2aSTejun Heo kn->flags |= KERNFS_SUICIDED; 14066b0afc2aSTejun Heo ret = true; 14076b0afc2aSTejun Heo } else { 14086b0afc2aSTejun Heo wait_queue_head_t *waitq = &kernfs_root(kn)->deactivate_waitq; 14096b0afc2aSTejun Heo DEFINE_WAIT(wait); 14106b0afc2aSTejun Heo 14116b0afc2aSTejun Heo while (true) { 14126b0afc2aSTejun Heo prepare_to_wait(waitq, &wait, TASK_UNINTERRUPTIBLE); 14136b0afc2aSTejun Heo 14146b0afc2aSTejun Heo if ((kn->flags & KERNFS_SUICIDED) && 14156b0afc2aSTejun Heo atomic_read(&kn->active) == KN_DEACTIVATED_BIAS) 14166b0afc2aSTejun Heo break; 14176b0afc2aSTejun Heo 14186b0afc2aSTejun Heo mutex_unlock(&kernfs_mutex); 14196b0afc2aSTejun Heo schedule(); 14206b0afc2aSTejun Heo mutex_lock(&kernfs_mutex); 14216b0afc2aSTejun Heo } 14226b0afc2aSTejun Heo finish_wait(waitq, &wait); 14236b0afc2aSTejun Heo WARN_ON_ONCE(!RB_EMPTY_NODE(&kn->rb)); 14246b0afc2aSTejun Heo ret = false; 14256b0afc2aSTejun Heo } 14266b0afc2aSTejun Heo 14276b0afc2aSTejun Heo /* 14286b0afc2aSTejun Heo * This must be done while holding kernfs_mutex; otherwise, waiting 14296b0afc2aSTejun Heo * for SUICIDED && deactivated could finish prematurely. 14306b0afc2aSTejun Heo */ 14316b0afc2aSTejun Heo kernfs_unbreak_active_protection(kn); 14326b0afc2aSTejun Heo 14336b0afc2aSTejun Heo mutex_unlock(&kernfs_mutex); 14346b0afc2aSTejun Heo return ret; 14356b0afc2aSTejun Heo } 14366b0afc2aSTejun Heo 14376b0afc2aSTejun Heo /** 1438324a56e1STejun Heo * kernfs_remove_by_name_ns - find a kernfs_node by name and remove it 1439324a56e1STejun Heo * @parent: parent of the target 1440324a56e1STejun Heo * @name: name of the kernfs_node to remove 1441324a56e1STejun Heo * @ns: namespace tag of the kernfs_node to remove 1442fd7b9f7bSTejun Heo * 1443324a56e1STejun Heo * Look for the kernfs_node with @name and @ns under @parent and remove it. 1444324a56e1STejun Heo * Returns 0 on success, -ENOENT if such entry doesn't exist. 1445fd7b9f7bSTejun Heo */ 1446324a56e1STejun Heo int kernfs_remove_by_name_ns(struct kernfs_node *parent, const char *name, 1447fd7b9f7bSTejun Heo const void *ns) 1448fd7b9f7bSTejun Heo { 1449324a56e1STejun Heo struct kernfs_node *kn; 1450fd7b9f7bSTejun Heo 1451324a56e1STejun Heo if (!parent) { 1452c637b8acSTejun Heo WARN(1, KERN_WARNING "kernfs: can not remove '%s', no directory\n", 1453fd7b9f7bSTejun Heo name); 1454fd7b9f7bSTejun Heo return -ENOENT; 1455fd7b9f7bSTejun Heo } 1456fd7b9f7bSTejun Heo 1457988cd7afSTejun Heo mutex_lock(&kernfs_mutex); 1458fd7b9f7bSTejun Heo 1459324a56e1STejun Heo kn = kernfs_find_ns(parent, name, ns); 1460324a56e1STejun Heo if (kn) 1461988cd7afSTejun Heo __kernfs_remove(kn); 1462fd7b9f7bSTejun Heo 1463988cd7afSTejun Heo mutex_unlock(&kernfs_mutex); 1464fd7b9f7bSTejun Heo 1465324a56e1STejun Heo if (kn) 1466fd7b9f7bSTejun Heo return 0; 1467fd7b9f7bSTejun Heo else 1468fd7b9f7bSTejun Heo return -ENOENT; 1469fd7b9f7bSTejun Heo } 1470fd7b9f7bSTejun Heo 1471fd7b9f7bSTejun Heo /** 1472fd7b9f7bSTejun Heo * kernfs_rename_ns - move and rename a kernfs_node 1473324a56e1STejun Heo * @kn: target node 1474fd7b9f7bSTejun Heo * @new_parent: new parent to put @sd under 1475fd7b9f7bSTejun Heo * @new_name: new name 1476fd7b9f7bSTejun Heo * @new_ns: new namespace tag 1477fd7b9f7bSTejun Heo */ 1478324a56e1STejun Heo int kernfs_rename_ns(struct kernfs_node *kn, struct kernfs_node *new_parent, 1479fd7b9f7bSTejun Heo const char *new_name, const void *new_ns) 1480fd7b9f7bSTejun Heo { 14813eef34adSTejun Heo struct kernfs_node *old_parent; 14823eef34adSTejun Heo const char *old_name = NULL; 1483fd7b9f7bSTejun Heo int error; 1484fd7b9f7bSTejun Heo 14853eef34adSTejun Heo /* can't move or rename root */ 14863eef34adSTejun Heo if (!kn->parent) 14873eef34adSTejun Heo return -EINVAL; 14883eef34adSTejun Heo 1489ae34372eSTejun Heo mutex_lock(&kernfs_mutex); 1490d0ae3d43STejun Heo 1491798c75a0SGreg Kroah-Hartman error = -ENOENT; 1492ea015218SEric W. Biederman if (!kernfs_active(kn) || !kernfs_active(new_parent) || 1493ea015218SEric W. Biederman (new_parent->flags & KERNFS_EMPTY_DIR)) 1494798c75a0SGreg Kroah-Hartman goto out; 1495798c75a0SGreg Kroah-Hartman 1496fd7b9f7bSTejun Heo error = 0; 1497adc5e8b5STejun Heo if ((kn->parent == new_parent) && (kn->ns == new_ns) && 1498adc5e8b5STejun Heo (strcmp(kn->name, new_name) == 0)) 1499798c75a0SGreg Kroah-Hartman goto out; /* nothing to rename */ 1500fd7b9f7bSTejun Heo 1501fd7b9f7bSTejun Heo error = -EEXIST; 1502fd7b9f7bSTejun Heo if (kernfs_find_ns(new_parent, new_name, new_ns)) 1503798c75a0SGreg Kroah-Hartman goto out; 1504fd7b9f7bSTejun Heo 1505324a56e1STejun Heo /* rename kernfs_node */ 1506adc5e8b5STejun Heo if (strcmp(kn->name, new_name) != 0) { 1507fd7b9f7bSTejun Heo error = -ENOMEM; 150875287a67SAndrzej Hajda new_name = kstrdup_const(new_name, GFP_KERNEL); 1509fd7b9f7bSTejun Heo if (!new_name) 1510798c75a0SGreg Kroah-Hartman goto out; 15113eef34adSTejun Heo } else { 15123eef34adSTejun Heo new_name = NULL; 1513fd7b9f7bSTejun Heo } 1514fd7b9f7bSTejun Heo 1515fd7b9f7bSTejun Heo /* 1516fd7b9f7bSTejun Heo * Move to the appropriate place in the appropriate directories rbtree. 1517fd7b9f7bSTejun Heo */ 1518c637b8acSTejun Heo kernfs_unlink_sibling(kn); 1519fd7b9f7bSTejun Heo kernfs_get(new_parent); 15203eef34adSTejun Heo 15213eef34adSTejun Heo /* rename_lock protects ->parent and ->name accessors */ 15223eef34adSTejun Heo spin_lock_irq(&kernfs_rename_lock); 15233eef34adSTejun Heo 15243eef34adSTejun Heo old_parent = kn->parent; 1525adc5e8b5STejun Heo kn->parent = new_parent; 15263eef34adSTejun Heo 15273eef34adSTejun Heo kn->ns = new_ns; 15283eef34adSTejun Heo if (new_name) { 15293eef34adSTejun Heo old_name = kn->name; 15303eef34adSTejun Heo kn->name = new_name; 15313eef34adSTejun Heo } 15323eef34adSTejun Heo 15333eef34adSTejun Heo spin_unlock_irq(&kernfs_rename_lock); 15343eef34adSTejun Heo 15359561a896STejun Heo kn->hash = kernfs_name_hash(kn->name, kn->ns); 1536c637b8acSTejun Heo kernfs_link_sibling(kn); 1537fd7b9f7bSTejun Heo 15383eef34adSTejun Heo kernfs_put(old_parent); 153975287a67SAndrzej Hajda kfree_const(old_name); 15403eef34adSTejun Heo 1541fd7b9f7bSTejun Heo error = 0; 1542ae34372eSTejun Heo out: 1543798c75a0SGreg Kroah-Hartman mutex_unlock(&kernfs_mutex); 1544fd7b9f7bSTejun Heo return error; 1545fd7b9f7bSTejun Heo } 1546fd7b9f7bSTejun Heo 1547fd7b9f7bSTejun Heo /* Relationship between s_mode and the DT_xxx types */ 1548324a56e1STejun Heo static inline unsigned char dt_type(struct kernfs_node *kn) 1549fd7b9f7bSTejun Heo { 1550adc5e8b5STejun Heo return (kn->mode >> 12) & 15; 1551fd7b9f7bSTejun Heo } 1552fd7b9f7bSTejun Heo 1553c637b8acSTejun Heo static int kernfs_dir_fop_release(struct inode *inode, struct file *filp) 1554fd7b9f7bSTejun Heo { 1555fd7b9f7bSTejun Heo kernfs_put(filp->private_data); 1556fd7b9f7bSTejun Heo return 0; 1557fd7b9f7bSTejun Heo } 1558fd7b9f7bSTejun Heo 1559c637b8acSTejun Heo static struct kernfs_node *kernfs_dir_pos(const void *ns, 1560324a56e1STejun Heo struct kernfs_node *parent, loff_t hash, struct kernfs_node *pos) 1561fd7b9f7bSTejun Heo { 1562fd7b9f7bSTejun Heo if (pos) { 156381c173cbSTejun Heo int valid = kernfs_active(pos) && 1564798c75a0SGreg Kroah-Hartman pos->parent == parent && hash == pos->hash; 1565fd7b9f7bSTejun Heo kernfs_put(pos); 1566fd7b9f7bSTejun Heo if (!valid) 1567fd7b9f7bSTejun Heo pos = NULL; 1568fd7b9f7bSTejun Heo } 1569fd7b9f7bSTejun Heo if (!pos && (hash > 1) && (hash < INT_MAX)) { 1570adc5e8b5STejun Heo struct rb_node *node = parent->dir.children.rb_node; 1571fd7b9f7bSTejun Heo while (node) { 1572324a56e1STejun Heo pos = rb_to_kn(node); 1573fd7b9f7bSTejun Heo 1574adc5e8b5STejun Heo if (hash < pos->hash) 1575fd7b9f7bSTejun Heo node = node->rb_left; 1576adc5e8b5STejun Heo else if (hash > pos->hash) 1577fd7b9f7bSTejun Heo node = node->rb_right; 1578fd7b9f7bSTejun Heo else 1579fd7b9f7bSTejun Heo break; 1580fd7b9f7bSTejun Heo } 1581fd7b9f7bSTejun Heo } 1582b9c9dad0STejun Heo /* Skip over entries which are dying/dead or in the wrong namespace */ 1583b9c9dad0STejun Heo while (pos && (!kernfs_active(pos) || pos->ns != ns)) { 1584adc5e8b5STejun Heo struct rb_node *node = rb_next(&pos->rb); 1585fd7b9f7bSTejun Heo if (!node) 1586fd7b9f7bSTejun Heo pos = NULL; 1587fd7b9f7bSTejun Heo else 1588324a56e1STejun Heo pos = rb_to_kn(node); 1589fd7b9f7bSTejun Heo } 1590fd7b9f7bSTejun Heo return pos; 1591fd7b9f7bSTejun Heo } 1592fd7b9f7bSTejun Heo 1593c637b8acSTejun Heo static struct kernfs_node *kernfs_dir_next_pos(const void *ns, 1594324a56e1STejun Heo struct kernfs_node *parent, ino_t ino, struct kernfs_node *pos) 1595fd7b9f7bSTejun Heo { 1596c637b8acSTejun Heo pos = kernfs_dir_pos(ns, parent, ino, pos); 1597b9c9dad0STejun Heo if (pos) { 1598fd7b9f7bSTejun Heo do { 1599adc5e8b5STejun Heo struct rb_node *node = rb_next(&pos->rb); 1600fd7b9f7bSTejun Heo if (!node) 1601fd7b9f7bSTejun Heo pos = NULL; 1602fd7b9f7bSTejun Heo else 1603324a56e1STejun Heo pos = rb_to_kn(node); 1604b9c9dad0STejun Heo } while (pos && (!kernfs_active(pos) || pos->ns != ns)); 1605b9c9dad0STejun Heo } 1606fd7b9f7bSTejun Heo return pos; 1607fd7b9f7bSTejun Heo } 1608fd7b9f7bSTejun Heo 1609c637b8acSTejun Heo static int kernfs_fop_readdir(struct file *file, struct dir_context *ctx) 1610fd7b9f7bSTejun Heo { 1611fd7b9f7bSTejun Heo struct dentry *dentry = file->f_path.dentry; 1612324a56e1STejun Heo struct kernfs_node *parent = dentry->d_fsdata; 1613324a56e1STejun Heo struct kernfs_node *pos = file->private_data; 1614fd7b9f7bSTejun Heo const void *ns = NULL; 1615fd7b9f7bSTejun Heo 1616fd7b9f7bSTejun Heo if (!dir_emit_dots(file, ctx)) 1617fd7b9f7bSTejun Heo return 0; 1618a797bfc3STejun Heo mutex_lock(&kernfs_mutex); 1619fd7b9f7bSTejun Heo 1620324a56e1STejun Heo if (kernfs_ns_enabled(parent)) 1621c525aaddSTejun Heo ns = kernfs_info(dentry->d_sb)->ns; 1622fd7b9f7bSTejun Heo 1623c637b8acSTejun Heo for (pos = kernfs_dir_pos(ns, parent, ctx->pos, pos); 1624fd7b9f7bSTejun Heo pos; 1625c637b8acSTejun Heo pos = kernfs_dir_next_pos(ns, parent, ctx->pos, pos)) { 1626adc5e8b5STejun Heo const char *name = pos->name; 1627fd7b9f7bSTejun Heo unsigned int type = dt_type(pos); 1628fd7b9f7bSTejun Heo int len = strlen(name); 1629adc5e8b5STejun Heo ino_t ino = pos->ino; 1630fd7b9f7bSTejun Heo 1631adc5e8b5STejun Heo ctx->pos = pos->hash; 1632fd7b9f7bSTejun Heo file->private_data = pos; 1633fd7b9f7bSTejun Heo kernfs_get(pos); 1634fd7b9f7bSTejun Heo 1635a797bfc3STejun Heo mutex_unlock(&kernfs_mutex); 1636fd7b9f7bSTejun Heo if (!dir_emit(ctx, name, len, ino, type)) 1637fd7b9f7bSTejun Heo return 0; 1638a797bfc3STejun Heo mutex_lock(&kernfs_mutex); 1639fd7b9f7bSTejun Heo } 1640a797bfc3STejun Heo mutex_unlock(&kernfs_mutex); 1641fd7b9f7bSTejun Heo file->private_data = NULL; 1642fd7b9f7bSTejun Heo ctx->pos = INT_MAX; 1643fd7b9f7bSTejun Heo return 0; 1644fd7b9f7bSTejun Heo } 1645fd7b9f7bSTejun Heo 1646a797bfc3STejun Heo const struct file_operations kernfs_dir_fops = { 1647fd7b9f7bSTejun Heo .read = generic_read_dir, 16488cb0d2c1SAl Viro .iterate_shared = kernfs_fop_readdir, 1649c637b8acSTejun Heo .release = kernfs_dir_fop_release, 16508cb0d2c1SAl Viro .llseek = generic_file_llseek, 1651fd7b9f7bSTejun Heo }; 1652