155716d26SThomas Gleixner // SPDX-License-Identifier: GPL-2.0-only 2b8441ed2STejun Heo /* 3b8441ed2STejun Heo * fs/kernfs/dir.c - kernfs directory implementation 4b8441ed2STejun Heo * 5b8441ed2STejun Heo * Copyright (c) 2001-3 Patrick Mochel 6b8441ed2STejun Heo * Copyright (c) 2007 SUSE Linux Products GmbH 7b8441ed2STejun Heo * Copyright (c) 2007, 2013 Tejun Heo <tj@kernel.org> 8b8441ed2STejun Heo */ 9fd7b9f7bSTejun Heo 10abd54f02STejun Heo #include <linux/sched.h> 11fd7b9f7bSTejun Heo #include <linux/fs.h> 12fd7b9f7bSTejun Heo #include <linux/namei.h> 13fd7b9f7bSTejun Heo #include <linux/idr.h> 14fd7b9f7bSTejun Heo #include <linux/slab.h> 15fd7b9f7bSTejun Heo #include <linux/security.h> 16fd7b9f7bSTejun Heo #include <linux/hash.h> 17fd7b9f7bSTejun Heo 18fd7b9f7bSTejun Heo #include "kernfs-internal.h" 19fd7b9f7bSTejun Heo 203eef34adSTejun Heo static DEFINE_SPINLOCK(kernfs_rename_lock); /* kn->parent and ->name */ 211a702dc8SHao Luo /* 221a702dc8SHao Luo * Don't use rename_lock to piggy back on pr_cont_buf. We don't want to 231a702dc8SHao Luo * call pr_cont() while holding rename_lock. Because sometimes pr_cont() 241a702dc8SHao Luo * will perform wakeups when releasing console_sem. Holding rename_lock 251a702dc8SHao Luo * will introduce deadlock if the scheduler reads the kernfs_name in the 261a702dc8SHao Luo * wakeup path. 271a702dc8SHao Luo */ 281a702dc8SHao Luo static DEFINE_SPINLOCK(kernfs_pr_cont_lock); 291a702dc8SHao Luo static char kernfs_pr_cont_buf[PATH_MAX]; /* protected by pr_cont_lock */ 307d35079fSShaohua Li static DEFINE_SPINLOCK(kernfs_idr_lock); /* root->ino_idr */ 31fd7b9f7bSTejun Heo 32adc5e8b5STejun Heo #define rb_to_kn(X) rb_entry((X), struct kernfs_node, rb) 33fd7b9f7bSTejun Heo 3481c173cbSTejun Heo static bool kernfs_active(struct kernfs_node *kn) 3581c173cbSTejun Heo { 36393c3714SMinchan Kim lockdep_assert_held(&kernfs_root(kn)->kernfs_rwsem); 3781c173cbSTejun Heo return atomic_read(&kn->active) >= 0; 3881c173cbSTejun Heo } 3981c173cbSTejun Heo 40182fd64bSTejun Heo static bool kernfs_lockdep(struct kernfs_node *kn) 41182fd64bSTejun Heo { 42182fd64bSTejun Heo #ifdef CONFIG_DEBUG_LOCK_ALLOC 43182fd64bSTejun Heo return kn->flags & KERNFS_LOCKDEP; 44182fd64bSTejun Heo #else 45182fd64bSTejun Heo return false; 46182fd64bSTejun Heo #endif 47182fd64bSTejun Heo } 48182fd64bSTejun Heo 493eef34adSTejun Heo static int kernfs_name_locked(struct kernfs_node *kn, char *buf, size_t buflen) 503eef34adSTejun Heo { 5117627157SKonstantin Khlebnikov if (!kn) 5217627157SKonstantin Khlebnikov return strlcpy(buf, "(null)", buflen); 5317627157SKonstantin Khlebnikov 543eef34adSTejun Heo return strlcpy(buf, kn->parent ? kn->name : "/", buflen); 553eef34adSTejun Heo } 563eef34adSTejun Heo 579f6df573SAditya Kali /* kernfs_node_depth - compute depth from @from to @to */ 589f6df573SAditya Kali static size_t kernfs_depth(struct kernfs_node *from, struct kernfs_node *to) 593eef34adSTejun Heo { 609f6df573SAditya Kali size_t depth = 0; 613eef34adSTejun Heo 629f6df573SAditya Kali while (to->parent && to != from) { 639f6df573SAditya Kali depth++; 649f6df573SAditya Kali to = to->parent; 653eef34adSTejun Heo } 669f6df573SAditya Kali return depth; 679f6df573SAditya Kali } 683eef34adSTejun Heo 699f6df573SAditya Kali static struct kernfs_node *kernfs_common_ancestor(struct kernfs_node *a, 709f6df573SAditya Kali struct kernfs_node *b) 719f6df573SAditya Kali { 729f6df573SAditya Kali size_t da, db; 739f6df573SAditya Kali struct kernfs_root *ra = kernfs_root(a), *rb = kernfs_root(b); 749f6df573SAditya Kali 759f6df573SAditya Kali if (ra != rb) 769f6df573SAditya Kali return NULL; 779f6df573SAditya Kali 789f6df573SAditya Kali da = kernfs_depth(ra->kn, a); 799f6df573SAditya Kali db = kernfs_depth(rb->kn, b); 809f6df573SAditya Kali 819f6df573SAditya Kali while (da > db) { 829f6df573SAditya Kali a = a->parent; 839f6df573SAditya Kali da--; 849f6df573SAditya Kali } 859f6df573SAditya Kali while (db > da) { 869f6df573SAditya Kali b = b->parent; 879f6df573SAditya Kali db--; 889f6df573SAditya Kali } 899f6df573SAditya Kali 909f6df573SAditya Kali /* worst case b and a will be the same at root */ 919f6df573SAditya Kali while (b != a) { 929f6df573SAditya Kali b = b->parent; 939f6df573SAditya Kali a = a->parent; 949f6df573SAditya Kali } 959f6df573SAditya Kali 969f6df573SAditya Kali return a; 979f6df573SAditya Kali } 989f6df573SAditya Kali 999f6df573SAditya Kali /** 1009f6df573SAditya Kali * kernfs_path_from_node_locked - find a pseudo-absolute path to @kn_to, 1019f6df573SAditya Kali * where kn_from is treated as root of the path. 1029f6df573SAditya Kali * @kn_from: kernfs node which should be treated as root for the path 1039f6df573SAditya Kali * @kn_to: kernfs node to which path is needed 1049f6df573SAditya Kali * @buf: buffer to copy the path into 1059f6df573SAditya Kali * @buflen: size of @buf 1069f6df573SAditya Kali * 1079f6df573SAditya Kali * We need to handle couple of scenarios here: 1089f6df573SAditya Kali * [1] when @kn_from is an ancestor of @kn_to at some level 1099f6df573SAditya Kali * kn_from: /n1/n2/n3 1109f6df573SAditya Kali * kn_to: /n1/n2/n3/n4/n5 1119f6df573SAditya Kali * result: /n4/n5 1129f6df573SAditya Kali * 1139f6df573SAditya Kali * [2] when @kn_from is on a different hierarchy and we need to find common 1149f6df573SAditya Kali * ancestor between @kn_from and @kn_to. 1159f6df573SAditya Kali * kn_from: /n1/n2/n3/n4 1169f6df573SAditya Kali * kn_to: /n1/n2/n5 1179f6df573SAditya Kali * result: /../../n5 1189f6df573SAditya Kali * OR 1199f6df573SAditya Kali * kn_from: /n1/n2/n3/n4/n5 [depth=5] 1209f6df573SAditya Kali * kn_to: /n1/n2/n3 [depth=3] 1219f6df573SAditya Kali * result: /../.. 1229f6df573SAditya Kali * 12317627157SKonstantin Khlebnikov * [3] when @kn_to is NULL result will be "(null)" 12417627157SKonstantin Khlebnikov * 1253abb1d90STejun Heo * Returns the length of the full path. If the full length is equal to or 1263abb1d90STejun Heo * greater than @buflen, @buf contains the truncated path with the trailing 1273abb1d90STejun Heo * '\0'. On error, -errno is returned. 1289f6df573SAditya Kali */ 1299f6df573SAditya Kali static int kernfs_path_from_node_locked(struct kernfs_node *kn_to, 1309f6df573SAditya Kali struct kernfs_node *kn_from, 1319f6df573SAditya Kali char *buf, size_t buflen) 1329f6df573SAditya Kali { 1339f6df573SAditya Kali struct kernfs_node *kn, *common; 1349f6df573SAditya Kali const char parent_str[] = "/.."; 1353abb1d90STejun Heo size_t depth_from, depth_to, len = 0; 1363abb1d90STejun Heo int i, j; 1379f6df573SAditya Kali 13817627157SKonstantin Khlebnikov if (!kn_to) 13917627157SKonstantin Khlebnikov return strlcpy(buf, "(null)", buflen); 14017627157SKonstantin Khlebnikov 1419f6df573SAditya Kali if (!kn_from) 1429f6df573SAditya Kali kn_from = kernfs_root(kn_to)->kn; 1439f6df573SAditya Kali 1449f6df573SAditya Kali if (kn_from == kn_to) 1459f6df573SAditya Kali return strlcpy(buf, "/", buflen); 1469f6df573SAditya Kali 147bbe70e4eSJia-Ju Bai if (!buf) 148bbe70e4eSJia-Ju Bai return -EINVAL; 149bbe70e4eSJia-Ju Bai 1509f6df573SAditya Kali common = kernfs_common_ancestor(kn_from, kn_to); 1519f6df573SAditya Kali if (WARN_ON(!common)) 1523abb1d90STejun Heo return -EINVAL; 1539f6df573SAditya Kali 1549f6df573SAditya Kali depth_to = kernfs_depth(common, kn_to); 1559f6df573SAditya Kali depth_from = kernfs_depth(common, kn_from); 1569f6df573SAditya Kali 1579f6df573SAditya Kali buf[0] = '\0'; 1589f6df573SAditya Kali 1599f6df573SAditya Kali for (i = 0; i < depth_from; i++) 1609f6df573SAditya Kali len += strlcpy(buf + len, parent_str, 1619f6df573SAditya Kali len < buflen ? buflen - len : 0); 1629f6df573SAditya Kali 1639f6df573SAditya Kali /* Calculate how many bytes we need for the rest */ 1643abb1d90STejun Heo for (i = depth_to - 1; i >= 0; i--) { 1653abb1d90STejun Heo for (kn = kn_to, j = 0; j < i; j++) 1663abb1d90STejun Heo kn = kn->parent; 1673abb1d90STejun Heo len += strlcpy(buf + len, "/", 1683abb1d90STejun Heo len < buflen ? buflen - len : 0); 1693abb1d90STejun Heo len += strlcpy(buf + len, kn->name, 1703abb1d90STejun Heo len < buflen ? buflen - len : 0); 1719f6df573SAditya Kali } 1729f6df573SAditya Kali 1733abb1d90STejun Heo return len; 1743eef34adSTejun Heo } 1753eef34adSTejun Heo 1763eef34adSTejun Heo /** 1773eef34adSTejun Heo * kernfs_name - obtain the name of a given node 1783eef34adSTejun Heo * @kn: kernfs_node of interest 1793eef34adSTejun Heo * @buf: buffer to copy @kn's name into 1803eef34adSTejun Heo * @buflen: size of @buf 1813eef34adSTejun Heo * 1823eef34adSTejun Heo * Copies the name of @kn into @buf of @buflen bytes. The behavior is 1833eef34adSTejun Heo * similar to strlcpy(). It returns the length of @kn's name and if @buf 1843eef34adSTejun Heo * isn't long enough, it's filled upto @buflen-1 and nul terminated. 1853eef34adSTejun Heo * 18617627157SKonstantin Khlebnikov * Fills buffer with "(null)" if @kn is NULL. 18717627157SKonstantin Khlebnikov * 1883eef34adSTejun Heo * This function can be called from any context. 1893eef34adSTejun Heo */ 1903eef34adSTejun Heo int kernfs_name(struct kernfs_node *kn, char *buf, size_t buflen) 1913eef34adSTejun Heo { 1923eef34adSTejun Heo unsigned long flags; 1933eef34adSTejun Heo int ret; 1943eef34adSTejun Heo 1953eef34adSTejun Heo spin_lock_irqsave(&kernfs_rename_lock, flags); 1963eef34adSTejun Heo ret = kernfs_name_locked(kn, buf, buflen); 1973eef34adSTejun Heo spin_unlock_irqrestore(&kernfs_rename_lock, flags); 1983eef34adSTejun Heo return ret; 1993eef34adSTejun Heo } 2003eef34adSTejun Heo 2013eef34adSTejun Heo /** 2029f6df573SAditya Kali * kernfs_path_from_node - build path of node @to relative to @from. 2039f6df573SAditya Kali * @from: parent kernfs_node relative to which we need to build the path 2049f6df573SAditya Kali * @to: kernfs_node of interest 2059f6df573SAditya Kali * @buf: buffer to copy @to's path into 2069f6df573SAditya Kali * @buflen: size of @buf 2079f6df573SAditya Kali * 2089f6df573SAditya Kali * Builds @to's path relative to @from in @buf. @from and @to must 2099f6df573SAditya Kali * be on the same kernfs-root. If @from is not parent of @to, then a relative 2109f6df573SAditya Kali * path (which includes '..'s) as needed to reach from @from to @to is 2119f6df573SAditya Kali * returned. 2129f6df573SAditya Kali * 2133abb1d90STejun Heo * Returns the length of the full path. If the full length is equal to or 2143abb1d90STejun Heo * greater than @buflen, @buf contains the truncated path with the trailing 2153abb1d90STejun Heo * '\0'. On error, -errno is returned. 2169f6df573SAditya Kali */ 2179f6df573SAditya Kali int kernfs_path_from_node(struct kernfs_node *to, struct kernfs_node *from, 2189f6df573SAditya Kali char *buf, size_t buflen) 2199f6df573SAditya Kali { 2209f6df573SAditya Kali unsigned long flags; 2219f6df573SAditya Kali int ret; 2229f6df573SAditya Kali 2239f6df573SAditya Kali spin_lock_irqsave(&kernfs_rename_lock, flags); 2249f6df573SAditya Kali ret = kernfs_path_from_node_locked(to, from, buf, buflen); 2259f6df573SAditya Kali spin_unlock_irqrestore(&kernfs_rename_lock, flags); 2269f6df573SAditya Kali return ret; 2279f6df573SAditya Kali } 2289f6df573SAditya Kali EXPORT_SYMBOL_GPL(kernfs_path_from_node); 2299f6df573SAditya Kali 2309f6df573SAditya Kali /** 2313eef34adSTejun Heo * pr_cont_kernfs_name - pr_cont name of a kernfs_node 2323eef34adSTejun Heo * @kn: kernfs_node of interest 2333eef34adSTejun Heo * 2343eef34adSTejun Heo * This function can be called from any context. 2353eef34adSTejun Heo */ 2363eef34adSTejun Heo void pr_cont_kernfs_name(struct kernfs_node *kn) 2373eef34adSTejun Heo { 2383eef34adSTejun Heo unsigned long flags; 2393eef34adSTejun Heo 2401a702dc8SHao Luo spin_lock_irqsave(&kernfs_pr_cont_lock, flags); 2413eef34adSTejun Heo 2421a702dc8SHao Luo kernfs_name(kn, kernfs_pr_cont_buf, sizeof(kernfs_pr_cont_buf)); 2433eef34adSTejun Heo pr_cont("%s", kernfs_pr_cont_buf); 2443eef34adSTejun Heo 2451a702dc8SHao Luo spin_unlock_irqrestore(&kernfs_pr_cont_lock, flags); 2463eef34adSTejun Heo } 2473eef34adSTejun Heo 2483eef34adSTejun Heo /** 2493eef34adSTejun Heo * pr_cont_kernfs_path - pr_cont path of a kernfs_node 2503eef34adSTejun Heo * @kn: kernfs_node of interest 2513eef34adSTejun Heo * 2523eef34adSTejun Heo * This function can be called from any context. 2533eef34adSTejun Heo */ 2543eef34adSTejun Heo void pr_cont_kernfs_path(struct kernfs_node *kn) 2553eef34adSTejun Heo { 2563eef34adSTejun Heo unsigned long flags; 2579f6df573SAditya Kali int sz; 2583eef34adSTejun Heo 2591a702dc8SHao Luo spin_lock_irqsave(&kernfs_pr_cont_lock, flags); 2603eef34adSTejun Heo 2611a702dc8SHao Luo sz = kernfs_path_from_node(kn, NULL, kernfs_pr_cont_buf, 2623eef34adSTejun Heo sizeof(kernfs_pr_cont_buf)); 2639f6df573SAditya Kali if (sz < 0) { 2649f6df573SAditya Kali pr_cont("(error)"); 2659f6df573SAditya Kali goto out; 2669f6df573SAditya Kali } 2673eef34adSTejun Heo 2689f6df573SAditya Kali if (sz >= sizeof(kernfs_pr_cont_buf)) { 2699f6df573SAditya Kali pr_cont("(name too long)"); 2709f6df573SAditya Kali goto out; 2719f6df573SAditya Kali } 2729f6df573SAditya Kali 2739f6df573SAditya Kali pr_cont("%s", kernfs_pr_cont_buf); 2749f6df573SAditya Kali 2759f6df573SAditya Kali out: 2761a702dc8SHao Luo spin_unlock_irqrestore(&kernfs_pr_cont_lock, flags); 2773eef34adSTejun Heo } 2783eef34adSTejun Heo 2793eef34adSTejun Heo /** 2803eef34adSTejun Heo * kernfs_get_parent - determine the parent node and pin it 2813eef34adSTejun Heo * @kn: kernfs_node of interest 2823eef34adSTejun Heo * 2833eef34adSTejun Heo * Determines @kn's parent, pins and returns it. This function can be 2843eef34adSTejun Heo * called from any context. 2853eef34adSTejun Heo */ 2863eef34adSTejun Heo struct kernfs_node *kernfs_get_parent(struct kernfs_node *kn) 2873eef34adSTejun Heo { 2883eef34adSTejun Heo struct kernfs_node *parent; 2893eef34adSTejun Heo unsigned long flags; 2903eef34adSTejun Heo 2913eef34adSTejun Heo spin_lock_irqsave(&kernfs_rename_lock, flags); 2923eef34adSTejun Heo parent = kn->parent; 2933eef34adSTejun Heo kernfs_get(parent); 2943eef34adSTejun Heo spin_unlock_irqrestore(&kernfs_rename_lock, flags); 2953eef34adSTejun Heo 2963eef34adSTejun Heo return parent; 2973eef34adSTejun Heo } 2983eef34adSTejun Heo 299fd7b9f7bSTejun Heo /** 300c637b8acSTejun Heo * kernfs_name_hash 301fd7b9f7bSTejun Heo * @name: Null terminated string to hash 302fd7b9f7bSTejun Heo * @ns: Namespace tag to hash 303fd7b9f7bSTejun Heo * 304fd7b9f7bSTejun Heo * Returns 31 bit hash of ns + name (so it fits in an off_t ) 305fd7b9f7bSTejun Heo */ 306c637b8acSTejun Heo static unsigned int kernfs_name_hash(const char *name, const void *ns) 307fd7b9f7bSTejun Heo { 3088387ff25SLinus Torvalds unsigned long hash = init_name_hash(ns); 309fd7b9f7bSTejun Heo unsigned int len = strlen(name); 310fd7b9f7bSTejun Heo while (len--) 311fd7b9f7bSTejun Heo hash = partial_name_hash(*name++, hash); 3128387ff25SLinus Torvalds hash = end_name_hash(hash); 313fd7b9f7bSTejun Heo hash &= 0x7fffffffU; 314fd7b9f7bSTejun Heo /* Reserve hash numbers 0, 1 and INT_MAX for magic directory entries */ 31588391d49SRichard Cochran if (hash < 2) 316fd7b9f7bSTejun Heo hash += 2; 317fd7b9f7bSTejun Heo if (hash >= INT_MAX) 318fd7b9f7bSTejun Heo hash = INT_MAX - 1; 319fd7b9f7bSTejun Heo return hash; 320fd7b9f7bSTejun Heo } 321fd7b9f7bSTejun Heo 322c637b8acSTejun Heo static int kernfs_name_compare(unsigned int hash, const char *name, 323324a56e1STejun Heo const void *ns, const struct kernfs_node *kn) 324fd7b9f7bSTejun Heo { 32572392ed0SRasmus Villemoes if (hash < kn->hash) 32672392ed0SRasmus Villemoes return -1; 32772392ed0SRasmus Villemoes if (hash > kn->hash) 32872392ed0SRasmus Villemoes return 1; 32972392ed0SRasmus Villemoes if (ns < kn->ns) 33072392ed0SRasmus Villemoes return -1; 33172392ed0SRasmus Villemoes if (ns > kn->ns) 33272392ed0SRasmus Villemoes return 1; 333adc5e8b5STejun Heo return strcmp(name, kn->name); 334fd7b9f7bSTejun Heo } 335fd7b9f7bSTejun Heo 336c637b8acSTejun Heo static int kernfs_sd_compare(const struct kernfs_node *left, 337324a56e1STejun Heo const struct kernfs_node *right) 338fd7b9f7bSTejun Heo { 339c637b8acSTejun Heo return kernfs_name_compare(left->hash, left->name, left->ns, right); 340fd7b9f7bSTejun Heo } 341fd7b9f7bSTejun Heo 342fd7b9f7bSTejun Heo /** 343c637b8acSTejun Heo * kernfs_link_sibling - link kernfs_node into sibling rbtree 344324a56e1STejun Heo * @kn: kernfs_node of interest 345fd7b9f7bSTejun Heo * 346324a56e1STejun Heo * Link @kn into its sibling rbtree which starts from 347adc5e8b5STejun Heo * @kn->parent->dir.children. 348fd7b9f7bSTejun Heo * 349fd7b9f7bSTejun Heo * Locking: 3507ba0273bSIan Kent * kernfs_rwsem held exclusive 351fd7b9f7bSTejun Heo * 352fd7b9f7bSTejun Heo * RETURNS: 353fd7b9f7bSTejun Heo * 0 on susccess -EEXIST on failure. 354fd7b9f7bSTejun Heo */ 355c637b8acSTejun Heo static int kernfs_link_sibling(struct kernfs_node *kn) 356fd7b9f7bSTejun Heo { 357adc5e8b5STejun Heo struct rb_node **node = &kn->parent->dir.children.rb_node; 358fd7b9f7bSTejun Heo struct rb_node *parent = NULL; 359fd7b9f7bSTejun Heo 360fd7b9f7bSTejun Heo while (*node) { 361324a56e1STejun Heo struct kernfs_node *pos; 362fd7b9f7bSTejun Heo int result; 363fd7b9f7bSTejun Heo 364324a56e1STejun Heo pos = rb_to_kn(*node); 365fd7b9f7bSTejun Heo parent = *node; 366c637b8acSTejun Heo result = kernfs_sd_compare(kn, pos); 367fd7b9f7bSTejun Heo if (result < 0) 368adc5e8b5STejun Heo node = &pos->rb.rb_left; 369fd7b9f7bSTejun Heo else if (result > 0) 370adc5e8b5STejun Heo node = &pos->rb.rb_right; 371fd7b9f7bSTejun Heo else 372fd7b9f7bSTejun Heo return -EEXIST; 373fd7b9f7bSTejun Heo } 374c1befb88SJianyu Zhan 375fd7b9f7bSTejun Heo /* add new node and rebalance the tree */ 376adc5e8b5STejun Heo rb_link_node(&kn->rb, parent, node); 377adc5e8b5STejun Heo rb_insert_color(&kn->rb, &kn->parent->dir.children); 378c1befb88SJianyu Zhan 379c1befb88SJianyu Zhan /* successfully added, account subdir number */ 380c1befb88SJianyu Zhan if (kernfs_type(kn) == KERNFS_DIR) 381c1befb88SJianyu Zhan kn->parent->dir.subdirs++; 382895adbecSIan Kent kernfs_inc_rev(kn->parent); 383c1befb88SJianyu Zhan 384fd7b9f7bSTejun Heo return 0; 385fd7b9f7bSTejun Heo } 386fd7b9f7bSTejun Heo 387fd7b9f7bSTejun Heo /** 388c637b8acSTejun Heo * kernfs_unlink_sibling - unlink kernfs_node from sibling rbtree 389324a56e1STejun Heo * @kn: kernfs_node of interest 390fd7b9f7bSTejun Heo * 39135beab06STejun Heo * Try to unlink @kn from its sibling rbtree which starts from 39235beab06STejun Heo * kn->parent->dir.children. Returns %true if @kn was actually 39335beab06STejun Heo * removed, %false if @kn wasn't on the rbtree. 394fd7b9f7bSTejun Heo * 395fd7b9f7bSTejun Heo * Locking: 3967ba0273bSIan Kent * kernfs_rwsem held exclusive 397fd7b9f7bSTejun Heo */ 39835beab06STejun Heo static bool kernfs_unlink_sibling(struct kernfs_node *kn) 399fd7b9f7bSTejun Heo { 40035beab06STejun Heo if (RB_EMPTY_NODE(&kn->rb)) 40135beab06STejun Heo return false; 40235beab06STejun Heo 403df23fc39STejun Heo if (kernfs_type(kn) == KERNFS_DIR) 404adc5e8b5STejun Heo kn->parent->dir.subdirs--; 405895adbecSIan Kent kernfs_inc_rev(kn->parent); 406fd7b9f7bSTejun Heo 407adc5e8b5STejun Heo rb_erase(&kn->rb, &kn->parent->dir.children); 40835beab06STejun Heo RB_CLEAR_NODE(&kn->rb); 40935beab06STejun Heo return true; 410fd7b9f7bSTejun Heo } 411fd7b9f7bSTejun Heo 412fd7b9f7bSTejun Heo /** 413c637b8acSTejun Heo * kernfs_get_active - get an active reference to kernfs_node 414324a56e1STejun Heo * @kn: kernfs_node to get an active reference to 415fd7b9f7bSTejun Heo * 416324a56e1STejun Heo * Get an active reference of @kn. This function is noop if @kn 417fd7b9f7bSTejun Heo * is NULL. 418fd7b9f7bSTejun Heo * 419fd7b9f7bSTejun Heo * RETURNS: 420324a56e1STejun Heo * Pointer to @kn on success, NULL on failure. 421fd7b9f7bSTejun Heo */ 422c637b8acSTejun Heo struct kernfs_node *kernfs_get_active(struct kernfs_node *kn) 423fd7b9f7bSTejun Heo { 424324a56e1STejun Heo if (unlikely(!kn)) 425fd7b9f7bSTejun Heo return NULL; 426fd7b9f7bSTejun Heo 427f4b3e631SGreg Kroah-Hartman if (!atomic_inc_unless_negative(&kn->active)) 428f4b3e631SGreg Kroah-Hartman return NULL; 429f4b3e631SGreg Kroah-Hartman 430182fd64bSTejun Heo if (kernfs_lockdep(kn)) 431324a56e1STejun Heo rwsem_acquire_read(&kn->dep_map, 0, 1, _RET_IP_); 432324a56e1STejun Heo return kn; 433fd7b9f7bSTejun Heo } 434fd7b9f7bSTejun Heo 435fd7b9f7bSTejun Heo /** 436c637b8acSTejun Heo * kernfs_put_active - put an active reference to kernfs_node 437324a56e1STejun Heo * @kn: kernfs_node to put an active reference to 438fd7b9f7bSTejun Heo * 439324a56e1STejun Heo * Put an active reference to @kn. This function is noop if @kn 440fd7b9f7bSTejun Heo * is NULL. 441fd7b9f7bSTejun Heo */ 442c637b8acSTejun Heo void kernfs_put_active(struct kernfs_node *kn) 443fd7b9f7bSTejun Heo { 444fd7b9f7bSTejun Heo int v; 445fd7b9f7bSTejun Heo 446324a56e1STejun Heo if (unlikely(!kn)) 447fd7b9f7bSTejun Heo return; 448fd7b9f7bSTejun Heo 449182fd64bSTejun Heo if (kernfs_lockdep(kn)) 4505facae4fSQian Cai rwsem_release(&kn->dep_map, _RET_IP_); 451adc5e8b5STejun Heo v = atomic_dec_return(&kn->active); 452df23fc39STejun Heo if (likely(v != KN_DEACTIVATED_BIAS)) 453fd7b9f7bSTejun Heo return; 454fd7b9f7bSTejun Heo 4552fd60da4SPeng Wang wake_up_all(&kernfs_root(kn)->deactivate_waitq); 456fd7b9f7bSTejun Heo } 457fd7b9f7bSTejun Heo 458fd7b9f7bSTejun Heo /** 45981c173cbSTejun Heo * kernfs_drain - drain kernfs_node 46081c173cbSTejun Heo * @kn: kernfs_node to drain 461fd7b9f7bSTejun Heo * 46281c173cbSTejun Heo * Drain existing usages and nuke all existing mmaps of @kn. Mutiple 46381c173cbSTejun Heo * removers may invoke this function concurrently on @kn and all will 46481c173cbSTejun Heo * return after draining is complete. 465fd7b9f7bSTejun Heo */ 46681c173cbSTejun Heo static void kernfs_drain(struct kernfs_node *kn) 467393c3714SMinchan Kim __releases(&kernfs_root(kn)->kernfs_rwsem) 468393c3714SMinchan Kim __acquires(&kernfs_root(kn)->kernfs_rwsem) 469fd7b9f7bSTejun Heo { 470abd54f02STejun Heo struct kernfs_root *root = kernfs_root(kn); 471fd7b9f7bSTejun Heo 472393c3714SMinchan Kim lockdep_assert_held_write(&root->kernfs_rwsem); 47381c173cbSTejun Heo WARN_ON_ONCE(kernfs_active(kn)); 474abd54f02STejun Heo 4752d7f9f8cSTejun Heo /* 4762d7f9f8cSTejun Heo * Skip draining if already fully drained. This avoids draining and its 4772d7f9f8cSTejun Heo * lockdep annotations for nodes which have never been activated 4782d7f9f8cSTejun Heo * allowing embedding kernfs_remove() in create error paths without 4792d7f9f8cSTejun Heo * worrying about draining. 4802d7f9f8cSTejun Heo */ 4812d7f9f8cSTejun Heo if (atomic_read(&kn->active) == KN_DEACTIVATED_BIAS && 4822d7f9f8cSTejun Heo !kernfs_should_drain_open_files(kn)) 4832d7f9f8cSTejun Heo return; 4842d7f9f8cSTejun Heo 485393c3714SMinchan Kim up_write(&root->kernfs_rwsem); 486abd54f02STejun Heo 487182fd64bSTejun Heo if (kernfs_lockdep(kn)) { 48835beab06STejun Heo rwsem_acquire(&kn->dep_map, 0, 0, _RET_IP_); 48935beab06STejun Heo if (atomic_read(&kn->active) != KN_DEACTIVATED_BIAS) 49035beab06STejun Heo lock_contended(&kn->dep_map, _RET_IP_); 49135beab06STejun Heo } 49235beab06STejun Heo 493abd54f02STejun Heo wait_event(root->deactivate_waitq, 494abd54f02STejun Heo atomic_read(&kn->active) == KN_DEACTIVATED_BIAS); 495fd7b9f7bSTejun Heo 496182fd64bSTejun Heo if (kernfs_lockdep(kn)) { 497324a56e1STejun Heo lock_acquired(&kn->dep_map, _RET_IP_); 4985facae4fSQian Cai rwsem_release(&kn->dep_map, _RET_IP_); 499fd7b9f7bSTejun Heo } 50035beab06STejun Heo 501bdb2fd7fSTejun Heo if (kernfs_should_drain_open_files(kn)) 5020e67db2fSTejun Heo kernfs_drain_open_files(kn); 503ccf02aafSTejun Heo 504393c3714SMinchan Kim down_write(&root->kernfs_rwsem); 505a6607930STejun Heo } 506fd7b9f7bSTejun Heo 507fd7b9f7bSTejun Heo /** 508324a56e1STejun Heo * kernfs_get - get a reference count on a kernfs_node 509324a56e1STejun Heo * @kn: the target kernfs_node 510fd7b9f7bSTejun Heo */ 511324a56e1STejun Heo void kernfs_get(struct kernfs_node *kn) 512fd7b9f7bSTejun Heo { 513324a56e1STejun Heo if (kn) { 514adc5e8b5STejun Heo WARN_ON(!atomic_read(&kn->count)); 515adc5e8b5STejun Heo atomic_inc(&kn->count); 516fd7b9f7bSTejun Heo } 517fd7b9f7bSTejun Heo } 518fd7b9f7bSTejun Heo EXPORT_SYMBOL_GPL(kernfs_get); 519fd7b9f7bSTejun Heo 520fd7b9f7bSTejun Heo /** 521324a56e1STejun Heo * kernfs_put - put a reference count on a kernfs_node 522324a56e1STejun Heo * @kn: the target kernfs_node 523fd7b9f7bSTejun Heo * 524324a56e1STejun Heo * Put a reference count of @kn and destroy it if it reached zero. 525fd7b9f7bSTejun Heo */ 526324a56e1STejun Heo void kernfs_put(struct kernfs_node *kn) 527fd7b9f7bSTejun Heo { 528324a56e1STejun Heo struct kernfs_node *parent; 529ba7443bcSTejun Heo struct kernfs_root *root; 530fd7b9f7bSTejun Heo 531adc5e8b5STejun Heo if (!kn || !atomic_dec_and_test(&kn->count)) 532fd7b9f7bSTejun Heo return; 533324a56e1STejun Heo root = kernfs_root(kn); 534fd7b9f7bSTejun Heo repeat: 53581c173cbSTejun Heo /* 53681c173cbSTejun Heo * Moving/renaming is always done while holding reference. 537adc5e8b5STejun Heo * kn->parent won't change beneath us. 538fd7b9f7bSTejun Heo */ 539adc5e8b5STejun Heo parent = kn->parent; 540fd7b9f7bSTejun Heo 54181c173cbSTejun Heo WARN_ONCE(atomic_read(&kn->active) != KN_DEACTIVATED_BIAS, 54281c173cbSTejun Heo "kernfs_put: %s/%s: released with incorrect active_ref %d\n", 54381c173cbSTejun Heo parent ? parent->name : "", kn->name, atomic_read(&kn->active)); 544fd7b9f7bSTejun Heo 545df23fc39STejun Heo if (kernfs_type(kn) == KERNFS_LINK) 546adc5e8b5STejun Heo kernfs_put(kn->symlink.target_kn); 547dfeb0750STejun Heo 54875287a67SAndrzej Hajda kfree_const(kn->name); 549dfeb0750STejun Heo 550adc5e8b5STejun Heo if (kn->iattr) { 551adc5e8b5STejun Heo simple_xattrs_free(&kn->iattr->xattrs); 55226e28d68SAyush Mittal kmem_cache_free(kernfs_iattrs_cache, kn->iattr); 5532322392bSTejun Heo } 5547d35079fSShaohua Li spin_lock(&kernfs_idr_lock); 55540430452STejun Heo idr_remove(&root->ino_idr, (u32)kernfs_ino(kn)); 5567d35079fSShaohua Li spin_unlock(&kernfs_idr_lock); 557a797bfc3STejun Heo kmem_cache_free(kernfs_node_cache, kn); 558fd7b9f7bSTejun Heo 559324a56e1STejun Heo kn = parent; 560324a56e1STejun Heo if (kn) { 561adc5e8b5STejun Heo if (atomic_dec_and_test(&kn->count)) 562fd7b9f7bSTejun Heo goto repeat; 563ba7443bcSTejun Heo } else { 564324a56e1STejun Heo /* just released the root kn, free @root too */ 5657d35079fSShaohua Li idr_destroy(&root->ino_idr); 566ba7443bcSTejun Heo kfree(root); 567ba7443bcSTejun Heo } 568fd7b9f7bSTejun Heo } 569fd7b9f7bSTejun Heo EXPORT_SYMBOL_GPL(kernfs_put); 570fd7b9f7bSTejun Heo 5710c23b225STejun Heo /** 5720c23b225STejun Heo * kernfs_node_from_dentry - determine kernfs_node associated with a dentry 5730c23b225STejun Heo * @dentry: the dentry in question 5740c23b225STejun Heo * 5750c23b225STejun Heo * Return the kernfs_node associated with @dentry. If @dentry is not a 5760c23b225STejun Heo * kernfs one, %NULL is returned. 5770c23b225STejun Heo * 5780c23b225STejun Heo * While the returned kernfs_node will stay accessible as long as @dentry 5790c23b225STejun Heo * is accessible, the returned node can be in any state and the caller is 5800c23b225STejun Heo * fully responsible for determining what's accessible. 5810c23b225STejun Heo */ 5820c23b225STejun Heo struct kernfs_node *kernfs_node_from_dentry(struct dentry *dentry) 5830c23b225STejun Heo { 5840288e7faSHui Su if (dentry->d_sb->s_op == &kernfs_sops) 585319ba91dSShaohua Li return kernfs_dentry_node(dentry); 5860c23b225STejun Heo return NULL; 5870c23b225STejun Heo } 5880c23b225STejun Heo 589db4aad20STejun Heo static struct kernfs_node *__kernfs_new_node(struct kernfs_root *root, 590e19dfdc8SOndrej Mosnacek struct kernfs_node *parent, 591db4aad20STejun Heo const char *name, umode_t mode, 592488dee96SDmitry Torokhov kuid_t uid, kgid_t gid, 593db4aad20STejun Heo unsigned flags) 594fd7b9f7bSTejun Heo { 595324a56e1STejun Heo struct kernfs_node *kn; 59640430452STejun Heo u32 id_highbits; 597bc755553STejun Heo int ret; 598fd7b9f7bSTejun Heo 599dfeb0750STejun Heo name = kstrdup_const(name, GFP_KERNEL); 600fd7b9f7bSTejun Heo if (!name) 601fd7b9f7bSTejun Heo return NULL; 602fd7b9f7bSTejun Heo 603a797bfc3STejun Heo kn = kmem_cache_zalloc(kernfs_node_cache, GFP_KERNEL); 604324a56e1STejun Heo if (!kn) 605fd7b9f7bSTejun Heo goto err_out1; 606fd7b9f7bSTejun Heo 6077d35079fSShaohua Li idr_preload(GFP_KERNEL); 6087d35079fSShaohua Li spin_lock(&kernfs_idr_lock); 6094a3ef68aSShaohua Li ret = idr_alloc_cyclic(&root->ino_idr, kn, 1, 0, GFP_ATOMIC); 61040430452STejun Heo if (ret >= 0 && ret < root->last_id_lowbits) 61140430452STejun Heo root->id_highbits++; 61240430452STejun Heo id_highbits = root->id_highbits; 61340430452STejun Heo root->last_id_lowbits = ret; 6147d35079fSShaohua Li spin_unlock(&kernfs_idr_lock); 6157d35079fSShaohua Li idr_preload_end(); 616bc755553STejun Heo if (ret < 0) 617fd7b9f7bSTejun Heo goto err_out2; 61867c0496eSTejun Heo 61940430452STejun Heo kn->id = (u64)id_highbits << 32 | ret; 620fd7b9f7bSTejun Heo 621b680b081STejun Heo atomic_set(&kn->count, 1); 62281c173cbSTejun Heo atomic_set(&kn->active, KN_DEACTIVATED_BIAS); 62335beab06STejun Heo RB_CLEAR_NODE(&kn->rb); 624fd7b9f7bSTejun Heo 625adc5e8b5STejun Heo kn->name = name; 626adc5e8b5STejun Heo kn->mode = mode; 62781c173cbSTejun Heo kn->flags = flags; 628fd7b9f7bSTejun Heo 629488dee96SDmitry Torokhov if (!uid_eq(uid, GLOBAL_ROOT_UID) || !gid_eq(gid, GLOBAL_ROOT_GID)) { 630488dee96SDmitry Torokhov struct iattr iattr = { 631488dee96SDmitry Torokhov .ia_valid = ATTR_UID | ATTR_GID, 632488dee96SDmitry Torokhov .ia_uid = uid, 633488dee96SDmitry Torokhov .ia_gid = gid, 634488dee96SDmitry Torokhov }; 635488dee96SDmitry Torokhov 636488dee96SDmitry Torokhov ret = __kernfs_setattr(kn, &iattr); 637488dee96SDmitry Torokhov if (ret < 0) 638488dee96SDmitry Torokhov goto err_out3; 639488dee96SDmitry Torokhov } 640488dee96SDmitry Torokhov 641e19dfdc8SOndrej Mosnacek if (parent) { 642e19dfdc8SOndrej Mosnacek ret = security_kernfs_init_security(parent, kn); 643e19dfdc8SOndrej Mosnacek if (ret) 644e19dfdc8SOndrej Mosnacek goto err_out3; 645e19dfdc8SOndrej Mosnacek } 646e19dfdc8SOndrej Mosnacek 647324a56e1STejun Heo return kn; 648fd7b9f7bSTejun Heo 649488dee96SDmitry Torokhov err_out3: 65040430452STejun Heo idr_remove(&root->ino_idr, (u32)kernfs_ino(kn)); 651fd7b9f7bSTejun Heo err_out2: 652a797bfc3STejun Heo kmem_cache_free(kernfs_node_cache, kn); 653fd7b9f7bSTejun Heo err_out1: 654dfeb0750STejun Heo kfree_const(name); 655fd7b9f7bSTejun Heo return NULL; 656fd7b9f7bSTejun Heo } 657fd7b9f7bSTejun Heo 658db4aad20STejun Heo struct kernfs_node *kernfs_new_node(struct kernfs_node *parent, 659db4aad20STejun Heo const char *name, umode_t mode, 660488dee96SDmitry Torokhov kuid_t uid, kgid_t gid, 661db4aad20STejun Heo unsigned flags) 662db4aad20STejun Heo { 663db4aad20STejun Heo struct kernfs_node *kn; 664db4aad20STejun Heo 665e19dfdc8SOndrej Mosnacek kn = __kernfs_new_node(kernfs_root(parent), parent, 666488dee96SDmitry Torokhov name, mode, uid, gid, flags); 667db4aad20STejun Heo if (kn) { 668db4aad20STejun Heo kernfs_get(parent); 669db4aad20STejun Heo kn->parent = parent; 670db4aad20STejun Heo } 671db4aad20STejun Heo return kn; 672db4aad20STejun Heo } 673db4aad20STejun Heo 674ba16b284SShaohua Li /* 675fe0f726cSTejun Heo * kernfs_find_and_get_node_by_id - get kernfs_node from node id 676ba16b284SShaohua Li * @root: the kernfs root 677fe0f726cSTejun Heo * @id: the target node id 678fe0f726cSTejun Heo * 679fe0f726cSTejun Heo * @id's lower 32bits encode ino and upper gen. If the gen portion is 680fe0f726cSTejun Heo * zero, all generations are matched. 681ba16b284SShaohua Li * 682ba16b284SShaohua Li * RETURNS: 683ba16b284SShaohua Li * NULL on failure. Return a kernfs node with reference counter incremented 684ba16b284SShaohua Li */ 685fe0f726cSTejun Heo struct kernfs_node *kernfs_find_and_get_node_by_id(struct kernfs_root *root, 686fe0f726cSTejun Heo u64 id) 687ba16b284SShaohua Li { 688ba16b284SShaohua Li struct kernfs_node *kn; 689fe0f726cSTejun Heo ino_t ino = kernfs_id_ino(id); 690fe0f726cSTejun Heo u32 gen = kernfs_id_gen(id); 691ba16b284SShaohua Li 692b680b081STejun Heo spin_lock(&kernfs_idr_lock); 693b680b081STejun Heo 69440430452STejun Heo kn = idr_find(&root->ino_idr, (u32)ino); 695ba16b284SShaohua Li if (!kn) 696b680b081STejun Heo goto err_unlock; 697ba16b284SShaohua Li 69840430452STejun Heo if (sizeof(ino_t) >= sizeof(u64)) { 69940430452STejun Heo /* we looked up with the low 32bits, compare the whole */ 70040430452STejun Heo if (kernfs_ino(kn) != ino) 70140430452STejun Heo goto err_unlock; 70240430452STejun Heo } else { 703fe0f726cSTejun Heo /* 0 matches all generations */ 704fe0f726cSTejun Heo if (unlikely(gen && kernfs_gen(kn) != gen)) 705fe0f726cSTejun Heo goto err_unlock; 70640430452STejun Heo } 707fe0f726cSTejun Heo 708c2549174STejun Heo if (unlikely(!kernfs_active(kn) || !atomic_inc_not_zero(&kn->count))) 709b680b081STejun Heo goto err_unlock; 710ba16b284SShaohua Li 711b680b081STejun Heo spin_unlock(&kernfs_idr_lock); 712ba16b284SShaohua Li return kn; 713b680b081STejun Heo err_unlock: 714b680b081STejun Heo spin_unlock(&kernfs_idr_lock); 715ba16b284SShaohua Li return NULL; 716ba16b284SShaohua Li } 717ba16b284SShaohua Li 718fd7b9f7bSTejun Heo /** 719c637b8acSTejun Heo * kernfs_add_one - add kernfs_node to parent without warning 720324a56e1STejun Heo * @kn: kernfs_node to be added 721fd7b9f7bSTejun Heo * 722db4aad20STejun Heo * The caller must already have initialized @kn->parent. This 723db4aad20STejun Heo * function increments nlink of the parent's inode if @kn is a 724db4aad20STejun Heo * directory and link into the children list of the parent. 725fd7b9f7bSTejun Heo * 726fd7b9f7bSTejun Heo * RETURNS: 727fd7b9f7bSTejun Heo * 0 on success, -EEXIST if entry with the given name already 728fd7b9f7bSTejun Heo * exists. 729fd7b9f7bSTejun Heo */ 730988cd7afSTejun Heo int kernfs_add_one(struct kernfs_node *kn) 731fd7b9f7bSTejun Heo { 732db4aad20STejun Heo struct kernfs_node *parent = kn->parent; 733393c3714SMinchan Kim struct kernfs_root *root = kernfs_root(parent); 734c525aaddSTejun Heo struct kernfs_iattrs *ps_iattr; 735988cd7afSTejun Heo bool has_ns; 736fd7b9f7bSTejun Heo int ret; 737fd7b9f7bSTejun Heo 738393c3714SMinchan Kim down_write(&root->kernfs_rwsem); 739988cd7afSTejun Heo 740988cd7afSTejun Heo ret = -EINVAL; 741988cd7afSTejun Heo has_ns = kernfs_ns_enabled(parent); 742988cd7afSTejun Heo if (WARN(has_ns != (bool)kn->ns, KERN_WARNING "kernfs: ns %s in '%s' for '%s'\n", 743988cd7afSTejun Heo has_ns ? "required" : "invalid", parent->name, kn->name)) 744988cd7afSTejun Heo goto out_unlock; 745fd7b9f7bSTejun Heo 746df23fc39STejun Heo if (kernfs_type(parent) != KERNFS_DIR) 747988cd7afSTejun Heo goto out_unlock; 748fd7b9f7bSTejun Heo 749988cd7afSTejun Heo ret = -ENOENT; 750c2549174STejun Heo if (parent->flags & (KERNFS_REMOVING | KERNFS_EMPTY_DIR)) 751988cd7afSTejun Heo goto out_unlock; 752798c75a0SGreg Kroah-Hartman 753c637b8acSTejun Heo kn->hash = kernfs_name_hash(kn->name, kn->ns); 754fd7b9f7bSTejun Heo 755c637b8acSTejun Heo ret = kernfs_link_sibling(kn); 756fd7b9f7bSTejun Heo if (ret) 757988cd7afSTejun Heo goto out_unlock; 758fd7b9f7bSTejun Heo 759fd7b9f7bSTejun Heo /* Update timestamps on the parent */ 760adc5e8b5STejun Heo ps_iattr = parent->iattr; 761fd7b9f7bSTejun Heo if (ps_iattr) { 76205895219SOndrej Mosnacek ktime_get_real_ts64(&ps_iattr->ia_ctime); 76305895219SOndrej Mosnacek ps_iattr->ia_mtime = ps_iattr->ia_ctime; 764fd7b9f7bSTejun Heo } 765fd7b9f7bSTejun Heo 766393c3714SMinchan Kim up_write(&root->kernfs_rwsem); 767d35258efSTejun Heo 768d35258efSTejun Heo /* 769d35258efSTejun Heo * Activate the new node unless CREATE_DEACTIVATED is requested. 770d35258efSTejun Heo * If not activated here, the kernfs user is responsible for 771d35258efSTejun Heo * activating the node with kernfs_activate(). A node which hasn't 772d35258efSTejun Heo * been activated is not visible to userland and its removal won't 773d35258efSTejun Heo * trigger deactivation. 774d35258efSTejun Heo */ 775d35258efSTejun Heo if (!(kernfs_root(kn)->flags & KERNFS_ROOT_CREATE_DEACTIVATED)) 776d35258efSTejun Heo kernfs_activate(kn); 777d35258efSTejun Heo return 0; 778d35258efSTejun Heo 779988cd7afSTejun Heo out_unlock: 780393c3714SMinchan Kim up_write(&root->kernfs_rwsem); 781988cd7afSTejun Heo return ret; 782fd7b9f7bSTejun Heo } 783fd7b9f7bSTejun Heo 784fd7b9f7bSTejun Heo /** 785324a56e1STejun Heo * kernfs_find_ns - find kernfs_node with the given name 786324a56e1STejun Heo * @parent: kernfs_node to search under 787fd7b9f7bSTejun Heo * @name: name to look for 788fd7b9f7bSTejun Heo * @ns: the namespace tag to use 789fd7b9f7bSTejun Heo * 790324a56e1STejun Heo * Look for kernfs_node with name @name under @parent. Returns pointer to 791324a56e1STejun Heo * the found kernfs_node on success, %NULL on failure. 792fd7b9f7bSTejun Heo */ 793324a56e1STejun Heo static struct kernfs_node *kernfs_find_ns(struct kernfs_node *parent, 794fd7b9f7bSTejun Heo const unsigned char *name, 795fd7b9f7bSTejun Heo const void *ns) 796fd7b9f7bSTejun Heo { 797adc5e8b5STejun Heo struct rb_node *node = parent->dir.children.rb_node; 798ac9bba03STejun Heo bool has_ns = kernfs_ns_enabled(parent); 799fd7b9f7bSTejun Heo unsigned int hash; 800fd7b9f7bSTejun Heo 801393c3714SMinchan Kim lockdep_assert_held(&kernfs_root(parent)->kernfs_rwsem); 802fd7b9f7bSTejun Heo 803fd7b9f7bSTejun Heo if (has_ns != (bool)ns) { 804c637b8acSTejun Heo WARN(1, KERN_WARNING "kernfs: ns %s in '%s' for '%s'\n", 805adc5e8b5STejun Heo has_ns ? "required" : "invalid", parent->name, name); 806fd7b9f7bSTejun Heo return NULL; 807fd7b9f7bSTejun Heo } 808fd7b9f7bSTejun Heo 809c637b8acSTejun Heo hash = kernfs_name_hash(name, ns); 810fd7b9f7bSTejun Heo while (node) { 811324a56e1STejun Heo struct kernfs_node *kn; 812fd7b9f7bSTejun Heo int result; 813fd7b9f7bSTejun Heo 814324a56e1STejun Heo kn = rb_to_kn(node); 815c637b8acSTejun Heo result = kernfs_name_compare(hash, name, ns, kn); 816fd7b9f7bSTejun Heo if (result < 0) 817fd7b9f7bSTejun Heo node = node->rb_left; 818fd7b9f7bSTejun Heo else if (result > 0) 819fd7b9f7bSTejun Heo node = node->rb_right; 820fd7b9f7bSTejun Heo else 821324a56e1STejun Heo return kn; 822fd7b9f7bSTejun Heo } 823fd7b9f7bSTejun Heo return NULL; 824fd7b9f7bSTejun Heo } 825fd7b9f7bSTejun Heo 826bd96f76aSTejun Heo static struct kernfs_node *kernfs_walk_ns(struct kernfs_node *parent, 827bd96f76aSTejun Heo const unsigned char *path, 828bd96f76aSTejun Heo const void *ns) 829bd96f76aSTejun Heo { 830e56ed358STejun Heo size_t len; 831e56ed358STejun Heo char *p, *name; 832bd96f76aSTejun Heo 833393c3714SMinchan Kim lockdep_assert_held_read(&kernfs_root(parent)->kernfs_rwsem); 834bd96f76aSTejun Heo 8351a702dc8SHao Luo spin_lock_irq(&kernfs_pr_cont_lock); 836e56ed358STejun Heo 837e56ed358STejun Heo len = strlcpy(kernfs_pr_cont_buf, path, sizeof(kernfs_pr_cont_buf)); 838e56ed358STejun Heo 839e56ed358STejun Heo if (len >= sizeof(kernfs_pr_cont_buf)) { 8401a702dc8SHao Luo spin_unlock_irq(&kernfs_pr_cont_lock); 841bd96f76aSTejun Heo return NULL; 842e56ed358STejun Heo } 843e56ed358STejun Heo 844e56ed358STejun Heo p = kernfs_pr_cont_buf; 845bd96f76aSTejun Heo 846bd96f76aSTejun Heo while ((name = strsep(&p, "/")) && parent) { 847bd96f76aSTejun Heo if (*name == '\0') 848bd96f76aSTejun Heo continue; 849bd96f76aSTejun Heo parent = kernfs_find_ns(parent, name, ns); 850bd96f76aSTejun Heo } 851bd96f76aSTejun Heo 8521a702dc8SHao Luo spin_unlock_irq(&kernfs_pr_cont_lock); 853e56ed358STejun Heo 854bd96f76aSTejun Heo return parent; 855bd96f76aSTejun Heo } 856bd96f76aSTejun Heo 857fd7b9f7bSTejun Heo /** 858324a56e1STejun Heo * kernfs_find_and_get_ns - find and get kernfs_node with the given name 859324a56e1STejun Heo * @parent: kernfs_node to search under 860fd7b9f7bSTejun Heo * @name: name to look for 861fd7b9f7bSTejun Heo * @ns: the namespace tag to use 862fd7b9f7bSTejun Heo * 863324a56e1STejun Heo * Look for kernfs_node with name @name under @parent and get a reference 864fd7b9f7bSTejun Heo * if found. This function may sleep and returns pointer to the found 865324a56e1STejun Heo * kernfs_node on success, %NULL on failure. 866fd7b9f7bSTejun Heo */ 867324a56e1STejun Heo struct kernfs_node *kernfs_find_and_get_ns(struct kernfs_node *parent, 868fd7b9f7bSTejun Heo const char *name, const void *ns) 869fd7b9f7bSTejun Heo { 870324a56e1STejun Heo struct kernfs_node *kn; 871393c3714SMinchan Kim struct kernfs_root *root = kernfs_root(parent); 872fd7b9f7bSTejun Heo 873393c3714SMinchan Kim down_read(&root->kernfs_rwsem); 874324a56e1STejun Heo kn = kernfs_find_ns(parent, name, ns); 875324a56e1STejun Heo kernfs_get(kn); 876393c3714SMinchan Kim up_read(&root->kernfs_rwsem); 877fd7b9f7bSTejun Heo 878324a56e1STejun Heo return kn; 879fd7b9f7bSTejun Heo } 880fd7b9f7bSTejun Heo EXPORT_SYMBOL_GPL(kernfs_find_and_get_ns); 881fd7b9f7bSTejun Heo 882fd7b9f7bSTejun Heo /** 883bd96f76aSTejun Heo * kernfs_walk_and_get_ns - find and get kernfs_node with the given path 884bd96f76aSTejun Heo * @parent: kernfs_node to search under 885bd96f76aSTejun Heo * @path: path to look for 886bd96f76aSTejun Heo * @ns: the namespace tag to use 887bd96f76aSTejun Heo * 888bd96f76aSTejun Heo * Look for kernfs_node with path @path under @parent and get a reference 889bd96f76aSTejun Heo * if found. This function may sleep and returns pointer to the found 890bd96f76aSTejun Heo * kernfs_node on success, %NULL on failure. 891bd96f76aSTejun Heo */ 892bd96f76aSTejun Heo struct kernfs_node *kernfs_walk_and_get_ns(struct kernfs_node *parent, 893bd96f76aSTejun Heo const char *path, const void *ns) 894bd96f76aSTejun Heo { 895bd96f76aSTejun Heo struct kernfs_node *kn; 896393c3714SMinchan Kim struct kernfs_root *root = kernfs_root(parent); 897bd96f76aSTejun Heo 898393c3714SMinchan Kim down_read(&root->kernfs_rwsem); 899bd96f76aSTejun Heo kn = kernfs_walk_ns(parent, path, ns); 900bd96f76aSTejun Heo kernfs_get(kn); 901393c3714SMinchan Kim up_read(&root->kernfs_rwsem); 902bd96f76aSTejun Heo 903bd96f76aSTejun Heo return kn; 904bd96f76aSTejun Heo } 905bd96f76aSTejun Heo 906bd96f76aSTejun Heo /** 907ba7443bcSTejun Heo * kernfs_create_root - create a new kernfs hierarchy 90890c07c89STejun Heo * @scops: optional syscall operations for the hierarchy 909d35258efSTejun Heo * @flags: KERNFS_ROOT_* flags 910ba7443bcSTejun Heo * @priv: opaque data associated with the new directory 911ba7443bcSTejun Heo * 912ba7443bcSTejun Heo * Returns the root of the new hierarchy on success, ERR_PTR() value on 913ba7443bcSTejun Heo * failure. 914ba7443bcSTejun Heo */ 91590c07c89STejun Heo struct kernfs_root *kernfs_create_root(struct kernfs_syscall_ops *scops, 916d35258efSTejun Heo unsigned int flags, void *priv) 917ba7443bcSTejun Heo { 918ba7443bcSTejun Heo struct kernfs_root *root; 919324a56e1STejun Heo struct kernfs_node *kn; 920ba7443bcSTejun Heo 921ba7443bcSTejun Heo root = kzalloc(sizeof(*root), GFP_KERNEL); 922ba7443bcSTejun Heo if (!root) 923ba7443bcSTejun Heo return ERR_PTR(-ENOMEM); 924ba7443bcSTejun Heo 9257d35079fSShaohua Li idr_init(&root->ino_idr); 926393c3714SMinchan Kim init_rwsem(&root->kernfs_rwsem); 9277d568a83STejun Heo INIT_LIST_HEAD(&root->supers); 92840430452STejun Heo 92940430452STejun Heo /* 93040430452STejun Heo * On 64bit ino setups, id is ino. On 32bit, low 32bits are ino. 93140430452STejun Heo * High bits generation. The starting value for both ino and 93240430452STejun Heo * genenration is 1. Initialize upper 32bit allocation 93340430452STejun Heo * accordingly. 93440430452STejun Heo */ 93540430452STejun Heo if (sizeof(ino_t) >= sizeof(u64)) 93640430452STejun Heo root->id_highbits = 0; 93740430452STejun Heo else 93840430452STejun Heo root->id_highbits = 1; 939bc755553STejun Heo 940e19dfdc8SOndrej Mosnacek kn = __kernfs_new_node(root, NULL, "", S_IFDIR | S_IRUGO | S_IXUGO, 941488dee96SDmitry Torokhov GLOBAL_ROOT_UID, GLOBAL_ROOT_GID, 942db4aad20STejun Heo KERNFS_DIR); 943324a56e1STejun Heo if (!kn) { 9447d35079fSShaohua Li idr_destroy(&root->ino_idr); 945ba7443bcSTejun Heo kfree(root); 946ba7443bcSTejun Heo return ERR_PTR(-ENOMEM); 947ba7443bcSTejun Heo } 948ba7443bcSTejun Heo 949324a56e1STejun Heo kn->priv = priv; 950adc5e8b5STejun Heo kn->dir.root = root; 951ba7443bcSTejun Heo 95290c07c89STejun Heo root->syscall_ops = scops; 953d35258efSTejun Heo root->flags = flags; 954324a56e1STejun Heo root->kn = kn; 955abd54f02STejun Heo init_waitqueue_head(&root->deactivate_waitq); 956ba7443bcSTejun Heo 957d35258efSTejun Heo if (!(root->flags & KERNFS_ROOT_CREATE_DEACTIVATED)) 958d35258efSTejun Heo kernfs_activate(kn); 959d35258efSTejun Heo 960ba7443bcSTejun Heo return root; 961ba7443bcSTejun Heo } 962ba7443bcSTejun Heo 963ba7443bcSTejun Heo /** 964ba7443bcSTejun Heo * kernfs_destroy_root - destroy a kernfs hierarchy 965ba7443bcSTejun Heo * @root: root of the hierarchy to destroy 966ba7443bcSTejun Heo * 967ba7443bcSTejun Heo * Destroy the hierarchy anchored at @root by removing all existing 968ba7443bcSTejun Heo * directories and destroying @root. 969ba7443bcSTejun Heo */ 970ba7443bcSTejun Heo void kernfs_destroy_root(struct kernfs_root *root) 971ba7443bcSTejun Heo { 972555a0ce4SMinchan Kim /* 973555a0ce4SMinchan Kim * kernfs_remove holds kernfs_rwsem from the root so the root 974555a0ce4SMinchan Kim * shouldn't be freed during the operation. 975555a0ce4SMinchan Kim */ 976555a0ce4SMinchan Kim kernfs_get(root->kn); 977555a0ce4SMinchan Kim kernfs_remove(root->kn); 978555a0ce4SMinchan Kim kernfs_put(root->kn); /* will also free @root */ 979ba7443bcSTejun Heo } 980ba7443bcSTejun Heo 981ba7443bcSTejun Heo /** 982f2eb478fSGreg Kroah-Hartman * kernfs_root_to_node - return the kernfs_node associated with a kernfs_root 983f2eb478fSGreg Kroah-Hartman * @root: root to use to lookup 984f2eb478fSGreg Kroah-Hartman */ 985f2eb478fSGreg Kroah-Hartman struct kernfs_node *kernfs_root_to_node(struct kernfs_root *root) 986f2eb478fSGreg Kroah-Hartman { 987f2eb478fSGreg Kroah-Hartman return root->kn; 988f2eb478fSGreg Kroah-Hartman } 989f2eb478fSGreg Kroah-Hartman 990f2eb478fSGreg Kroah-Hartman /** 991fd7b9f7bSTejun Heo * kernfs_create_dir_ns - create a directory 992fd7b9f7bSTejun Heo * @parent: parent in which to create a new directory 993fd7b9f7bSTejun Heo * @name: name of the new directory 994bb8b9d09STejun Heo * @mode: mode of the new directory 995488dee96SDmitry Torokhov * @uid: uid of the new directory 996488dee96SDmitry Torokhov * @gid: gid of the new directory 997fd7b9f7bSTejun Heo * @priv: opaque data associated with the new directory 998fd7b9f7bSTejun Heo * @ns: optional namespace tag of the directory 999fd7b9f7bSTejun Heo * 1000fd7b9f7bSTejun Heo * Returns the created node on success, ERR_PTR() value on failure. 1001fd7b9f7bSTejun Heo */ 1002324a56e1STejun Heo struct kernfs_node *kernfs_create_dir_ns(struct kernfs_node *parent, 1003bb8b9d09STejun Heo const char *name, umode_t mode, 1004488dee96SDmitry Torokhov kuid_t uid, kgid_t gid, 1005bb8b9d09STejun Heo void *priv, const void *ns) 1006fd7b9f7bSTejun Heo { 1007324a56e1STejun Heo struct kernfs_node *kn; 1008fd7b9f7bSTejun Heo int rc; 1009fd7b9f7bSTejun Heo 1010fd7b9f7bSTejun Heo /* allocate */ 1011488dee96SDmitry Torokhov kn = kernfs_new_node(parent, name, mode | S_IFDIR, 1012488dee96SDmitry Torokhov uid, gid, KERNFS_DIR); 1013324a56e1STejun Heo if (!kn) 1014fd7b9f7bSTejun Heo return ERR_PTR(-ENOMEM); 1015fd7b9f7bSTejun Heo 1016adc5e8b5STejun Heo kn->dir.root = parent->dir.root; 1017adc5e8b5STejun Heo kn->ns = ns; 1018324a56e1STejun Heo kn->priv = priv; 1019fd7b9f7bSTejun Heo 1020fd7b9f7bSTejun Heo /* link in */ 1021988cd7afSTejun Heo rc = kernfs_add_one(kn); 1022fd7b9f7bSTejun Heo if (!rc) 1023324a56e1STejun Heo return kn; 1024fd7b9f7bSTejun Heo 1025324a56e1STejun Heo kernfs_put(kn); 1026fd7b9f7bSTejun Heo return ERR_PTR(rc); 1027fd7b9f7bSTejun Heo } 1028fd7b9f7bSTejun Heo 1029ea015218SEric W. Biederman /** 1030ea015218SEric W. Biederman * kernfs_create_empty_dir - create an always empty directory 1031ea015218SEric W. Biederman * @parent: parent in which to create a new directory 1032ea015218SEric W. Biederman * @name: name of the new directory 1033ea015218SEric W. Biederman * 1034ea015218SEric W. Biederman * Returns the created node on success, ERR_PTR() value on failure. 1035ea015218SEric W. Biederman */ 1036ea015218SEric W. Biederman struct kernfs_node *kernfs_create_empty_dir(struct kernfs_node *parent, 1037ea015218SEric W. Biederman const char *name) 1038ea015218SEric W. Biederman { 1039ea015218SEric W. Biederman struct kernfs_node *kn; 1040ea015218SEric W. Biederman int rc; 1041ea015218SEric W. Biederman 1042ea015218SEric W. Biederman /* allocate */ 1043488dee96SDmitry Torokhov kn = kernfs_new_node(parent, name, S_IRUGO|S_IXUGO|S_IFDIR, 1044488dee96SDmitry Torokhov GLOBAL_ROOT_UID, GLOBAL_ROOT_GID, KERNFS_DIR); 1045ea015218SEric W. Biederman if (!kn) 1046ea015218SEric W. Biederman return ERR_PTR(-ENOMEM); 1047ea015218SEric W. Biederman 1048ea015218SEric W. Biederman kn->flags |= KERNFS_EMPTY_DIR; 1049ea015218SEric W. Biederman kn->dir.root = parent->dir.root; 1050ea015218SEric W. Biederman kn->ns = NULL; 1051ea015218SEric W. Biederman kn->priv = NULL; 1052ea015218SEric W. Biederman 1053ea015218SEric W. Biederman /* link in */ 1054ea015218SEric W. Biederman rc = kernfs_add_one(kn); 1055ea015218SEric W. Biederman if (!rc) 1056ea015218SEric W. Biederman return kn; 1057ea015218SEric W. Biederman 1058ea015218SEric W. Biederman kernfs_put(kn); 1059ea015218SEric W. Biederman return ERR_PTR(rc); 1060ea015218SEric W. Biederman } 1061ea015218SEric W. Biederman 1062d826e036SIan Kent static int kernfs_dop_revalidate(struct dentry *dentry, unsigned int flags) 1063d826e036SIan Kent { 1064d826e036SIan Kent struct kernfs_node *kn; 1065393c3714SMinchan Kim struct kernfs_root *root; 1066d826e036SIan Kent 1067d826e036SIan Kent if (flags & LOOKUP_RCU) 1068d826e036SIan Kent return -ECHILD; 1069d826e036SIan Kent 1070c7e7c042SIan Kent /* Negative hashed dentry? */ 1071c7e7c042SIan Kent if (d_really_is_negative(dentry)) { 1072c7e7c042SIan Kent struct kernfs_node *parent; 1073c7e7c042SIan Kent 1074c7e7c042SIan Kent /* If the kernfs parent node has changed discard and 1075c7e7c042SIan Kent * proceed to ->lookup. 1076c7e7c042SIan Kent */ 1077c7e7c042SIan Kent spin_lock(&dentry->d_lock); 1078c7e7c042SIan Kent parent = kernfs_dentry_node(dentry->d_parent); 1079c7e7c042SIan Kent if (parent) { 1080c7e7c042SIan Kent spin_unlock(&dentry->d_lock); 1081393c3714SMinchan Kim root = kernfs_root(parent); 1082393c3714SMinchan Kim down_read(&root->kernfs_rwsem); 1083393c3714SMinchan Kim if (kernfs_dir_changed(parent, dentry)) { 1084393c3714SMinchan Kim up_read(&root->kernfs_rwsem); 1085c7e7c042SIan Kent return 0; 1086c7e7c042SIan Kent } 1087393c3714SMinchan Kim up_read(&root->kernfs_rwsem); 1088393c3714SMinchan Kim } else 1089c7e7c042SIan Kent spin_unlock(&dentry->d_lock); 1090c7e7c042SIan Kent 1091c7e7c042SIan Kent /* The kernfs parent node hasn't changed, leave the 1092c7e7c042SIan Kent * dentry negative and return success. 1093c7e7c042SIan Kent */ 1094c7e7c042SIan Kent return 1; 1095c7e7c042SIan Kent } 1096d826e036SIan Kent 1097d826e036SIan Kent kn = kernfs_dentry_node(dentry); 1098393c3714SMinchan Kim root = kernfs_root(kn); 1099393c3714SMinchan Kim down_read(&root->kernfs_rwsem); 1100d826e036SIan Kent 1101d826e036SIan Kent /* The kernfs node has been deactivated */ 1102d826e036SIan Kent if (!kernfs_active(kn)) 1103d826e036SIan Kent goto out_bad; 1104d826e036SIan Kent 1105d826e036SIan Kent /* The kernfs node has been moved? */ 1106d826e036SIan Kent if (kernfs_dentry_node(dentry->d_parent) != kn->parent) 1107d826e036SIan Kent goto out_bad; 1108d826e036SIan Kent 1109d826e036SIan Kent /* The kernfs node has been renamed */ 1110d826e036SIan Kent if (strcmp(dentry->d_name.name, kn->name) != 0) 1111d826e036SIan Kent goto out_bad; 1112d826e036SIan Kent 1113d826e036SIan Kent /* The kernfs node has been moved to a different namespace */ 1114d826e036SIan Kent if (kn->parent && kernfs_ns_enabled(kn->parent) && 1115d826e036SIan Kent kernfs_info(dentry->d_sb)->ns != kn->ns) 1116d826e036SIan Kent goto out_bad; 1117d826e036SIan Kent 1118393c3714SMinchan Kim up_read(&root->kernfs_rwsem); 1119d826e036SIan Kent return 1; 1120d826e036SIan Kent out_bad: 1121393c3714SMinchan Kim up_read(&root->kernfs_rwsem); 1122d826e036SIan Kent return 0; 1123d826e036SIan Kent } 1124d826e036SIan Kent 1125d826e036SIan Kent const struct dentry_operations kernfs_dops = { 1126d826e036SIan Kent .d_revalidate = kernfs_dop_revalidate, 1127d826e036SIan Kent }; 1128d826e036SIan Kent 1129c637b8acSTejun Heo static struct dentry *kernfs_iop_lookup(struct inode *dir, 1130c637b8acSTejun Heo struct dentry *dentry, 1131fd7b9f7bSTejun Heo unsigned int flags) 1132fd7b9f7bSTejun Heo { 1133319ba91dSShaohua Li struct kernfs_node *parent = dir->i_private; 1134324a56e1STejun Heo struct kernfs_node *kn; 1135393c3714SMinchan Kim struct kernfs_root *root; 1136c7e7c042SIan Kent struct inode *inode = NULL; 1137fd7b9f7bSTejun Heo const void *ns = NULL; 1138fd7b9f7bSTejun Heo 1139393c3714SMinchan Kim root = kernfs_root(parent); 1140393c3714SMinchan Kim down_read(&root->kernfs_rwsem); 1141324a56e1STejun Heo if (kernfs_ns_enabled(parent)) 1142c525aaddSTejun Heo ns = kernfs_info(dir->i_sb)->ns; 1143fd7b9f7bSTejun Heo 1144324a56e1STejun Heo kn = kernfs_find_ns(parent, dentry->d_name.name, ns); 1145fd7b9f7bSTejun Heo /* attach dentry and inode */ 1146410d591aSIan Kent if (kn) { 1147410d591aSIan Kent /* Inactive nodes are invisible to the VFS so don't 1148410d591aSIan Kent * create a negative. 1149410d591aSIan Kent */ 1150410d591aSIan Kent if (!kernfs_active(kn)) { 1151393c3714SMinchan Kim up_read(&root->kernfs_rwsem); 1152410d591aSIan Kent return NULL; 1153410d591aSIan Kent } 1154c637b8acSTejun Heo inode = kernfs_get_inode(dir->i_sb, kn); 1155c7e7c042SIan Kent if (!inode) 1156c7e7c042SIan Kent inode = ERR_PTR(-ENOMEM); 1157fd7b9f7bSTejun Heo } 1158df38d852SHou Tao /* 1159df38d852SHou Tao * Needed for negative dentry validation. 1160df38d852SHou Tao * The negative dentry can be created in kernfs_iop_lookup() 1161df38d852SHou Tao * or transforms from positive dentry in dentry_unlink_inode() 1162df38d852SHou Tao * called from vfs_rmdir(). 1163df38d852SHou Tao */ 1164df38d852SHou Tao if (!IS_ERR(inode)) 1165c7e7c042SIan Kent kernfs_set_rev(parent, dentry); 1166393c3714SMinchan Kim up_read(&root->kernfs_rwsem); 1167c7e7c042SIan Kent 1168df6192f4SIan Kent /* instantiate and hash (possibly negative) dentry */ 1169df6192f4SIan Kent return d_splice_alias(inode, dentry); 1170fd7b9f7bSTejun Heo } 1171fd7b9f7bSTejun Heo 1172549c7297SChristian Brauner static int kernfs_iop_mkdir(struct user_namespace *mnt_userns, 1173549c7297SChristian Brauner struct inode *dir, struct dentry *dentry, 117480b9bbefSTejun Heo umode_t mode) 117580b9bbefSTejun Heo { 117680b9bbefSTejun Heo struct kernfs_node *parent = dir->i_private; 117790c07c89STejun Heo struct kernfs_syscall_ops *scops = kernfs_root(parent)->syscall_ops; 117807c7530dSTejun Heo int ret; 117980b9bbefSTejun Heo 118090c07c89STejun Heo if (!scops || !scops->mkdir) 118180b9bbefSTejun Heo return -EPERM; 118280b9bbefSTejun Heo 118307c7530dSTejun Heo if (!kernfs_get_active(parent)) 118407c7530dSTejun Heo return -ENODEV; 118507c7530dSTejun Heo 118690c07c89STejun Heo ret = scops->mkdir(parent, dentry->d_name.name, mode); 118707c7530dSTejun Heo 118807c7530dSTejun Heo kernfs_put_active(parent); 118907c7530dSTejun Heo return ret; 119080b9bbefSTejun Heo } 119180b9bbefSTejun Heo 119280b9bbefSTejun Heo static int kernfs_iop_rmdir(struct inode *dir, struct dentry *dentry) 119380b9bbefSTejun Heo { 1194319ba91dSShaohua Li struct kernfs_node *kn = kernfs_dentry_node(dentry); 119590c07c89STejun Heo struct kernfs_syscall_ops *scops = kernfs_root(kn)->syscall_ops; 119607c7530dSTejun Heo int ret; 119780b9bbefSTejun Heo 119890c07c89STejun Heo if (!scops || !scops->rmdir) 119980b9bbefSTejun Heo return -EPERM; 120080b9bbefSTejun Heo 120107c7530dSTejun Heo if (!kernfs_get_active(kn)) 120207c7530dSTejun Heo return -ENODEV; 120307c7530dSTejun Heo 120490c07c89STejun Heo ret = scops->rmdir(kn); 120507c7530dSTejun Heo 120607c7530dSTejun Heo kernfs_put_active(kn); 120707c7530dSTejun Heo return ret; 120880b9bbefSTejun Heo } 120980b9bbefSTejun Heo 1210549c7297SChristian Brauner static int kernfs_iop_rename(struct user_namespace *mnt_userns, 1211549c7297SChristian Brauner struct inode *old_dir, struct dentry *old_dentry, 12121cd66c93SMiklos Szeredi struct inode *new_dir, struct dentry *new_dentry, 12131cd66c93SMiklos Szeredi unsigned int flags) 121480b9bbefSTejun Heo { 1215319ba91dSShaohua Li struct kernfs_node *kn = kernfs_dentry_node(old_dentry); 121680b9bbefSTejun Heo struct kernfs_node *new_parent = new_dir->i_private; 121790c07c89STejun Heo struct kernfs_syscall_ops *scops = kernfs_root(kn)->syscall_ops; 121807c7530dSTejun Heo int ret; 121980b9bbefSTejun Heo 12201cd66c93SMiklos Szeredi if (flags) 12211cd66c93SMiklos Szeredi return -EINVAL; 12221cd66c93SMiklos Szeredi 122390c07c89STejun Heo if (!scops || !scops->rename) 122480b9bbefSTejun Heo return -EPERM; 122580b9bbefSTejun Heo 122607c7530dSTejun Heo if (!kernfs_get_active(kn)) 122707c7530dSTejun Heo return -ENODEV; 122807c7530dSTejun Heo 122907c7530dSTejun Heo if (!kernfs_get_active(new_parent)) { 123007c7530dSTejun Heo kernfs_put_active(kn); 123107c7530dSTejun Heo return -ENODEV; 123207c7530dSTejun Heo } 123307c7530dSTejun Heo 123490c07c89STejun Heo ret = scops->rename(kn, new_parent, new_dentry->d_name.name); 123507c7530dSTejun Heo 123607c7530dSTejun Heo kernfs_put_active(new_parent); 123707c7530dSTejun Heo kernfs_put_active(kn); 123807c7530dSTejun Heo return ret; 123980b9bbefSTejun Heo } 124080b9bbefSTejun Heo 1241a797bfc3STejun Heo const struct inode_operations kernfs_dir_iops = { 1242c637b8acSTejun Heo .lookup = kernfs_iop_lookup, 1243c637b8acSTejun Heo .permission = kernfs_iop_permission, 1244c637b8acSTejun Heo .setattr = kernfs_iop_setattr, 1245c637b8acSTejun Heo .getattr = kernfs_iop_getattr, 1246c637b8acSTejun Heo .listxattr = kernfs_iop_listxattr, 124780b9bbefSTejun Heo 124880b9bbefSTejun Heo .mkdir = kernfs_iop_mkdir, 124980b9bbefSTejun Heo .rmdir = kernfs_iop_rmdir, 125080b9bbefSTejun Heo .rename = kernfs_iop_rename, 1251fd7b9f7bSTejun Heo }; 1252fd7b9f7bSTejun Heo 1253c637b8acSTejun Heo static struct kernfs_node *kernfs_leftmost_descendant(struct kernfs_node *pos) 1254fd7b9f7bSTejun Heo { 1255324a56e1STejun Heo struct kernfs_node *last; 1256fd7b9f7bSTejun Heo 1257fd7b9f7bSTejun Heo while (true) { 1258fd7b9f7bSTejun Heo struct rb_node *rbn; 1259fd7b9f7bSTejun Heo 1260fd7b9f7bSTejun Heo last = pos; 1261fd7b9f7bSTejun Heo 1262df23fc39STejun Heo if (kernfs_type(pos) != KERNFS_DIR) 1263fd7b9f7bSTejun Heo break; 1264fd7b9f7bSTejun Heo 1265adc5e8b5STejun Heo rbn = rb_first(&pos->dir.children); 1266fd7b9f7bSTejun Heo if (!rbn) 1267fd7b9f7bSTejun Heo break; 1268fd7b9f7bSTejun Heo 1269324a56e1STejun Heo pos = rb_to_kn(rbn); 1270fd7b9f7bSTejun Heo } 1271fd7b9f7bSTejun Heo 1272fd7b9f7bSTejun Heo return last; 1273fd7b9f7bSTejun Heo } 1274fd7b9f7bSTejun Heo 1275fd7b9f7bSTejun Heo /** 1276c637b8acSTejun Heo * kernfs_next_descendant_post - find the next descendant for post-order walk 1277fd7b9f7bSTejun Heo * @pos: the current position (%NULL to initiate traversal) 1278324a56e1STejun Heo * @root: kernfs_node whose descendants to walk 1279fd7b9f7bSTejun Heo * 1280fd7b9f7bSTejun Heo * Find the next descendant to visit for post-order traversal of @root's 1281fd7b9f7bSTejun Heo * descendants. @root is included in the iteration and the last node to be 1282fd7b9f7bSTejun Heo * visited. 1283fd7b9f7bSTejun Heo */ 1284c637b8acSTejun Heo static struct kernfs_node *kernfs_next_descendant_post(struct kernfs_node *pos, 1285324a56e1STejun Heo struct kernfs_node *root) 1286fd7b9f7bSTejun Heo { 1287fd7b9f7bSTejun Heo struct rb_node *rbn; 1288fd7b9f7bSTejun Heo 1289393c3714SMinchan Kim lockdep_assert_held_write(&kernfs_root(root)->kernfs_rwsem); 1290fd7b9f7bSTejun Heo 1291fd7b9f7bSTejun Heo /* if first iteration, visit leftmost descendant which may be root */ 1292fd7b9f7bSTejun Heo if (!pos) 1293c637b8acSTejun Heo return kernfs_leftmost_descendant(root); 1294fd7b9f7bSTejun Heo 1295fd7b9f7bSTejun Heo /* if we visited @root, we're done */ 1296fd7b9f7bSTejun Heo if (pos == root) 1297fd7b9f7bSTejun Heo return NULL; 1298fd7b9f7bSTejun Heo 1299fd7b9f7bSTejun Heo /* if there's an unvisited sibling, visit its leftmost descendant */ 1300adc5e8b5STejun Heo rbn = rb_next(&pos->rb); 1301fd7b9f7bSTejun Heo if (rbn) 1302c637b8acSTejun Heo return kernfs_leftmost_descendant(rb_to_kn(rbn)); 1303fd7b9f7bSTejun Heo 1304fd7b9f7bSTejun Heo /* no sibling left, visit parent */ 1305adc5e8b5STejun Heo return pos->parent; 1306fd7b9f7bSTejun Heo } 1307fd7b9f7bSTejun Heo 1308f8eb145eSTejun Heo static void kernfs_activate_one(struct kernfs_node *kn) 1309f8eb145eSTejun Heo { 1310f8eb145eSTejun Heo lockdep_assert_held_write(&kernfs_root(kn)->kernfs_rwsem); 1311f8eb145eSTejun Heo 1312f8eb145eSTejun Heo kn->flags |= KERNFS_ACTIVATED; 1313f8eb145eSTejun Heo 1314783bd07dSTejun Heo if (kernfs_active(kn) || (kn->flags & (KERNFS_HIDDEN | KERNFS_REMOVING))) 1315f8eb145eSTejun Heo return; 1316f8eb145eSTejun Heo 1317f8eb145eSTejun Heo WARN_ON_ONCE(kn->parent && RB_EMPTY_NODE(&kn->rb)); 1318f8eb145eSTejun Heo WARN_ON_ONCE(atomic_read(&kn->active) != KN_DEACTIVATED_BIAS); 1319f8eb145eSTejun Heo 1320f8eb145eSTejun Heo atomic_sub(KN_DEACTIVATED_BIAS, &kn->active); 1321f8eb145eSTejun Heo } 1322f8eb145eSTejun Heo 1323d35258efSTejun Heo /** 1324d35258efSTejun Heo * kernfs_activate - activate a node which started deactivated 1325d35258efSTejun Heo * @kn: kernfs_node whose subtree is to be activated 1326d35258efSTejun Heo * 1327d35258efSTejun Heo * If the root has KERNFS_ROOT_CREATE_DEACTIVATED set, a newly created node 1328d35258efSTejun Heo * needs to be explicitly activated. A node which hasn't been activated 1329d35258efSTejun Heo * isn't visible to userland and deactivation is skipped during its 1330d35258efSTejun Heo * removal. This is useful to construct atomic init sequences where 1331d35258efSTejun Heo * creation of multiple nodes should either succeed or fail atomically. 1332d35258efSTejun Heo * 1333d35258efSTejun Heo * The caller is responsible for ensuring that this function is not called 1334d35258efSTejun Heo * after kernfs_remove*() is invoked on @kn. 1335d35258efSTejun Heo */ 1336d35258efSTejun Heo void kernfs_activate(struct kernfs_node *kn) 1337d35258efSTejun Heo { 1338d35258efSTejun Heo struct kernfs_node *pos; 1339393c3714SMinchan Kim struct kernfs_root *root = kernfs_root(kn); 1340d35258efSTejun Heo 1341393c3714SMinchan Kim down_write(&root->kernfs_rwsem); 1342d35258efSTejun Heo 1343d35258efSTejun Heo pos = NULL; 1344f8eb145eSTejun Heo while ((pos = kernfs_next_descendant_post(pos, kn))) 1345f8eb145eSTejun Heo kernfs_activate_one(pos); 1346d35258efSTejun Heo 1347393c3714SMinchan Kim up_write(&root->kernfs_rwsem); 1348d35258efSTejun Heo } 1349d35258efSTejun Heo 1350783bd07dSTejun Heo /** 1351783bd07dSTejun Heo * kernfs_show - show or hide a node 1352783bd07dSTejun Heo * @kn: kernfs_node to show or hide 1353783bd07dSTejun Heo * @show: whether to show or hide 1354783bd07dSTejun Heo * 1355783bd07dSTejun Heo * If @show is %false, @kn is marked hidden and deactivated. A hidden node is 1356783bd07dSTejun Heo * ignored in future activaitons. If %true, the mark is removed and activation 1357783bd07dSTejun Heo * state is restored. This function won't implicitly activate a new node in a 1358783bd07dSTejun Heo * %KERNFS_ROOT_CREATE_DEACTIVATED root which hasn't been activated yet. 1359783bd07dSTejun Heo * 1360783bd07dSTejun Heo * To avoid recursion complexities, directories aren't supported for now. 1361783bd07dSTejun Heo */ 1362783bd07dSTejun Heo void kernfs_show(struct kernfs_node *kn, bool show) 1363783bd07dSTejun Heo { 1364783bd07dSTejun Heo struct kernfs_root *root = kernfs_root(kn); 1365783bd07dSTejun Heo 1366783bd07dSTejun Heo if (WARN_ON_ONCE(kernfs_type(kn) == KERNFS_DIR)) 1367783bd07dSTejun Heo return; 1368783bd07dSTejun Heo 1369783bd07dSTejun Heo down_write(&root->kernfs_rwsem); 1370783bd07dSTejun Heo 1371783bd07dSTejun Heo if (show) { 1372783bd07dSTejun Heo kn->flags &= ~KERNFS_HIDDEN; 1373783bd07dSTejun Heo if (kn->flags & KERNFS_ACTIVATED) 1374783bd07dSTejun Heo kernfs_activate_one(kn); 1375783bd07dSTejun Heo } else { 1376783bd07dSTejun Heo kn->flags |= KERNFS_HIDDEN; 1377783bd07dSTejun Heo if (kernfs_active(kn)) 1378783bd07dSTejun Heo atomic_add(KN_DEACTIVATED_BIAS, &kn->active); 1379783bd07dSTejun Heo kernfs_drain(kn); 1380783bd07dSTejun Heo } 1381783bd07dSTejun Heo 1382783bd07dSTejun Heo up_write(&root->kernfs_rwsem); 1383783bd07dSTejun Heo } 1384783bd07dSTejun Heo 1385988cd7afSTejun Heo static void __kernfs_remove(struct kernfs_node *kn) 1386fd7b9f7bSTejun Heo { 138735beab06STejun Heo struct kernfs_node *pos; 138835beab06STejun Heo 138972b5d5aeSYushan Zhou /* Short-circuit if non-root @kn has already finished removal. */ 139072b5d5aeSYushan Zhou if (!kn) 139172b5d5aeSYushan Zhou return; 139272b5d5aeSYushan Zhou 1393393c3714SMinchan Kim lockdep_assert_held_write(&kernfs_root(kn)->kernfs_rwsem); 1394fd7b9f7bSTejun Heo 13956b0afc2aSTejun Heo /* 13966b0afc2aSTejun Heo * This is for kernfs_remove_self() which plays with active ref 13976b0afc2aSTejun Heo * after removal. 13986b0afc2aSTejun Heo */ 139972b5d5aeSYushan Zhou if (kn->parent && RB_EMPTY_NODE(&kn->rb)) 1400ce9b499cSGreg Kroah-Hartman return; 1401ce9b499cSGreg Kroah-Hartman 1402c637b8acSTejun Heo pr_debug("kernfs %s: removing\n", kn->name); 1403fd7b9f7bSTejun Heo 1404c2549174STejun Heo /* prevent new usage by marking all nodes removing and deactivating */ 140535beab06STejun Heo pos = NULL; 1406c2549174STejun Heo while ((pos = kernfs_next_descendant_post(pos, kn))) { 1407c2549174STejun Heo pos->flags |= KERNFS_REMOVING; 140881c173cbSTejun Heo if (kernfs_active(pos)) 140981c173cbSTejun Heo atomic_add(KN_DEACTIVATED_BIAS, &pos->active); 1410c2549174STejun Heo } 141135beab06STejun Heo 141235beab06STejun Heo /* deactivate and unlink the subtree node-by-node */ 1413fd7b9f7bSTejun Heo do { 141435beab06STejun Heo pos = kernfs_leftmost_descendant(kn); 141535beab06STejun Heo 141635beab06STejun Heo /* 14172d7f9f8cSTejun Heo * kernfs_drain() may drop kernfs_rwsem temporarily and @pos's 141881c173cbSTejun Heo * base ref could have been put by someone else by the time 141981c173cbSTejun Heo * the function returns. Make sure it doesn't go away 142081c173cbSTejun Heo * underneath us. 142135beab06STejun Heo */ 142235beab06STejun Heo kernfs_get(pos); 142335beab06STejun Heo 142481c173cbSTejun Heo kernfs_drain(pos); 142535beab06STejun Heo 142635beab06STejun Heo /* 142735beab06STejun Heo * kernfs_unlink_sibling() succeeds once per node. Use it 142835beab06STejun Heo * to decide who's responsible for cleanups. 142935beab06STejun Heo */ 143035beab06STejun Heo if (!pos->parent || kernfs_unlink_sibling(pos)) { 143135beab06STejun Heo struct kernfs_iattrs *ps_iattr = 143235beab06STejun Heo pos->parent ? pos->parent->iattr : NULL; 143335beab06STejun Heo 143435beab06STejun Heo /* update timestamps on the parent */ 143535beab06STejun Heo if (ps_iattr) { 143605895219SOndrej Mosnacek ktime_get_real_ts64(&ps_iattr->ia_ctime); 143705895219SOndrej Mosnacek ps_iattr->ia_mtime = ps_iattr->ia_ctime; 143835beab06STejun Heo } 143935beab06STejun Heo 1440988cd7afSTejun Heo kernfs_put(pos); 144135beab06STejun Heo } 144235beab06STejun Heo 144335beab06STejun Heo kernfs_put(pos); 144435beab06STejun Heo } while (pos != kn); 1445fd7b9f7bSTejun Heo } 1446fd7b9f7bSTejun Heo 1447fd7b9f7bSTejun Heo /** 1448324a56e1STejun Heo * kernfs_remove - remove a kernfs_node recursively 1449324a56e1STejun Heo * @kn: the kernfs_node to remove 1450fd7b9f7bSTejun Heo * 1451324a56e1STejun Heo * Remove @kn along with all its subdirectories and files. 1452fd7b9f7bSTejun Heo */ 1453324a56e1STejun Heo void kernfs_remove(struct kernfs_node *kn) 1454fd7b9f7bSTejun Heo { 1455ad8d8693SMinchan Kim struct kernfs_root *root; 1456ad8d8693SMinchan Kim 1457ad8d8693SMinchan Kim if (!kn) 1458ad8d8693SMinchan Kim return; 1459ad8d8693SMinchan Kim 1460ad8d8693SMinchan Kim root = kernfs_root(kn); 1461393c3714SMinchan Kim 1462393c3714SMinchan Kim down_write(&root->kernfs_rwsem); 1463988cd7afSTejun Heo __kernfs_remove(kn); 1464393c3714SMinchan Kim up_write(&root->kernfs_rwsem); 1465fd7b9f7bSTejun Heo } 1466fd7b9f7bSTejun Heo 1467fd7b9f7bSTejun Heo /** 14686b0afc2aSTejun Heo * kernfs_break_active_protection - break out of active protection 14696b0afc2aSTejun Heo * @kn: the self kernfs_node 14706b0afc2aSTejun Heo * 14716b0afc2aSTejun Heo * The caller must be running off of a kernfs operation which is invoked 14726b0afc2aSTejun Heo * with an active reference - e.g. one of kernfs_ops. Each invocation of 14736b0afc2aSTejun Heo * this function must also be matched with an invocation of 14746b0afc2aSTejun Heo * kernfs_unbreak_active_protection(). 14756b0afc2aSTejun Heo * 14766b0afc2aSTejun Heo * This function releases the active reference of @kn the caller is 14776b0afc2aSTejun Heo * holding. Once this function is called, @kn may be removed at any point 14786b0afc2aSTejun Heo * and the caller is solely responsible for ensuring that the objects it 14796b0afc2aSTejun Heo * dereferences are accessible. 14806b0afc2aSTejun Heo */ 14816b0afc2aSTejun Heo void kernfs_break_active_protection(struct kernfs_node *kn) 14826b0afc2aSTejun Heo { 14836b0afc2aSTejun Heo /* 14846b0afc2aSTejun Heo * Take out ourself out of the active ref dependency chain. If 14856b0afc2aSTejun Heo * we're called without an active ref, lockdep will complain. 14866b0afc2aSTejun Heo */ 14876b0afc2aSTejun Heo kernfs_put_active(kn); 14886b0afc2aSTejun Heo } 14896b0afc2aSTejun Heo 14906b0afc2aSTejun Heo /** 14916b0afc2aSTejun Heo * kernfs_unbreak_active_protection - undo kernfs_break_active_protection() 14926b0afc2aSTejun Heo * @kn: the self kernfs_node 14936b0afc2aSTejun Heo * 14946b0afc2aSTejun Heo * If kernfs_break_active_protection() was called, this function must be 14956b0afc2aSTejun Heo * invoked before finishing the kernfs operation. Note that while this 14966b0afc2aSTejun Heo * function restores the active reference, it doesn't and can't actually 14976b0afc2aSTejun Heo * restore the active protection - @kn may already or be in the process of 14986b0afc2aSTejun Heo * being removed. Once kernfs_break_active_protection() is invoked, that 14996b0afc2aSTejun Heo * protection is irreversibly gone for the kernfs operation instance. 15006b0afc2aSTejun Heo * 15016b0afc2aSTejun Heo * While this function may be called at any point after 15026b0afc2aSTejun Heo * kernfs_break_active_protection() is invoked, its most useful location 15036b0afc2aSTejun Heo * would be right before the enclosing kernfs operation returns. 15046b0afc2aSTejun Heo */ 15056b0afc2aSTejun Heo void kernfs_unbreak_active_protection(struct kernfs_node *kn) 15066b0afc2aSTejun Heo { 15076b0afc2aSTejun Heo /* 15086b0afc2aSTejun Heo * @kn->active could be in any state; however, the increment we do 15096b0afc2aSTejun Heo * here will be undone as soon as the enclosing kernfs operation 15106b0afc2aSTejun Heo * finishes and this temporary bump can't break anything. If @kn 15116b0afc2aSTejun Heo * is alive, nothing changes. If @kn is being deactivated, the 15126b0afc2aSTejun Heo * soon-to-follow put will either finish deactivation or restore 15136b0afc2aSTejun Heo * deactivated state. If @kn is already removed, the temporary 15146b0afc2aSTejun Heo * bump is guaranteed to be gone before @kn is released. 15156b0afc2aSTejun Heo */ 15166b0afc2aSTejun Heo atomic_inc(&kn->active); 15176b0afc2aSTejun Heo if (kernfs_lockdep(kn)) 15186b0afc2aSTejun Heo rwsem_acquire(&kn->dep_map, 0, 1, _RET_IP_); 15196b0afc2aSTejun Heo } 15206b0afc2aSTejun Heo 15216b0afc2aSTejun Heo /** 15226b0afc2aSTejun Heo * kernfs_remove_self - remove a kernfs_node from its own method 15236b0afc2aSTejun Heo * @kn: the self kernfs_node to remove 15246b0afc2aSTejun Heo * 15256b0afc2aSTejun Heo * The caller must be running off of a kernfs operation which is invoked 15266b0afc2aSTejun Heo * with an active reference - e.g. one of kernfs_ops. This can be used to 15276b0afc2aSTejun Heo * implement a file operation which deletes itself. 15286b0afc2aSTejun Heo * 15296b0afc2aSTejun Heo * For example, the "delete" file for a sysfs device directory can be 15306b0afc2aSTejun Heo * implemented by invoking kernfs_remove_self() on the "delete" file 15316b0afc2aSTejun Heo * itself. This function breaks the circular dependency of trying to 15326b0afc2aSTejun Heo * deactivate self while holding an active ref itself. It isn't necessary 15336b0afc2aSTejun Heo * to modify the usual removal path to use kernfs_remove_self(). The 15346b0afc2aSTejun Heo * "delete" implementation can simply invoke kernfs_remove_self() on self 15356b0afc2aSTejun Heo * before proceeding with the usual removal path. kernfs will ignore later 15366b0afc2aSTejun Heo * kernfs_remove() on self. 15376b0afc2aSTejun Heo * 15386b0afc2aSTejun Heo * kernfs_remove_self() can be called multiple times concurrently on the 15396b0afc2aSTejun Heo * same kernfs_node. Only the first one actually performs removal and 15406b0afc2aSTejun Heo * returns %true. All others will wait until the kernfs operation which 15416b0afc2aSTejun Heo * won self-removal finishes and return %false. Note that the losers wait 15426b0afc2aSTejun Heo * for the completion of not only the winning kernfs_remove_self() but also 15436b0afc2aSTejun Heo * the whole kernfs_ops which won the arbitration. This can be used to 15446b0afc2aSTejun Heo * guarantee, for example, all concurrent writes to a "delete" file to 15456b0afc2aSTejun Heo * finish only after the whole operation is complete. 15466b0afc2aSTejun Heo */ 15476b0afc2aSTejun Heo bool kernfs_remove_self(struct kernfs_node *kn) 15486b0afc2aSTejun Heo { 15496b0afc2aSTejun Heo bool ret; 1550393c3714SMinchan Kim struct kernfs_root *root = kernfs_root(kn); 15516b0afc2aSTejun Heo 1552393c3714SMinchan Kim down_write(&root->kernfs_rwsem); 15536b0afc2aSTejun Heo kernfs_break_active_protection(kn); 15546b0afc2aSTejun Heo 15556b0afc2aSTejun Heo /* 15566b0afc2aSTejun Heo * SUICIDAL is used to arbitrate among competing invocations. Only 15576b0afc2aSTejun Heo * the first one will actually perform removal. When the removal 15586b0afc2aSTejun Heo * is complete, SUICIDED is set and the active ref is restored 15597ba0273bSIan Kent * while kernfs_rwsem for held exclusive. The ones which lost 15607ba0273bSIan Kent * arbitration waits for SUICIDED && drained which can happen only 15617ba0273bSIan Kent * after the enclosing kernfs operation which executed the winning 15627ba0273bSIan Kent * instance of kernfs_remove_self() finished. 15636b0afc2aSTejun Heo */ 15646b0afc2aSTejun Heo if (!(kn->flags & KERNFS_SUICIDAL)) { 15656b0afc2aSTejun Heo kn->flags |= KERNFS_SUICIDAL; 15666b0afc2aSTejun Heo __kernfs_remove(kn); 15676b0afc2aSTejun Heo kn->flags |= KERNFS_SUICIDED; 15686b0afc2aSTejun Heo ret = true; 15696b0afc2aSTejun Heo } else { 15706b0afc2aSTejun Heo wait_queue_head_t *waitq = &kernfs_root(kn)->deactivate_waitq; 15716b0afc2aSTejun Heo DEFINE_WAIT(wait); 15726b0afc2aSTejun Heo 15736b0afc2aSTejun Heo while (true) { 15746b0afc2aSTejun Heo prepare_to_wait(waitq, &wait, TASK_UNINTERRUPTIBLE); 15756b0afc2aSTejun Heo 15766b0afc2aSTejun Heo if ((kn->flags & KERNFS_SUICIDED) && 15776b0afc2aSTejun Heo atomic_read(&kn->active) == KN_DEACTIVATED_BIAS) 15786b0afc2aSTejun Heo break; 15796b0afc2aSTejun Heo 1580393c3714SMinchan Kim up_write(&root->kernfs_rwsem); 15816b0afc2aSTejun Heo schedule(); 1582393c3714SMinchan Kim down_write(&root->kernfs_rwsem); 15836b0afc2aSTejun Heo } 15846b0afc2aSTejun Heo finish_wait(waitq, &wait); 15856b0afc2aSTejun Heo WARN_ON_ONCE(!RB_EMPTY_NODE(&kn->rb)); 15866b0afc2aSTejun Heo ret = false; 15876b0afc2aSTejun Heo } 15886b0afc2aSTejun Heo 15896b0afc2aSTejun Heo /* 15907ba0273bSIan Kent * This must be done while kernfs_rwsem held exclusive; otherwise, 15917ba0273bSIan Kent * waiting for SUICIDED && deactivated could finish prematurely. 15926b0afc2aSTejun Heo */ 15936b0afc2aSTejun Heo kernfs_unbreak_active_protection(kn); 15946b0afc2aSTejun Heo 1595393c3714SMinchan Kim up_write(&root->kernfs_rwsem); 15966b0afc2aSTejun Heo return ret; 15976b0afc2aSTejun Heo } 15986b0afc2aSTejun Heo 15996b0afc2aSTejun Heo /** 1600324a56e1STejun Heo * kernfs_remove_by_name_ns - find a kernfs_node by name and remove it 1601324a56e1STejun Heo * @parent: parent of the target 1602324a56e1STejun Heo * @name: name of the kernfs_node to remove 1603324a56e1STejun Heo * @ns: namespace tag of the kernfs_node to remove 1604fd7b9f7bSTejun Heo * 1605324a56e1STejun Heo * Look for the kernfs_node with @name and @ns under @parent and remove it. 1606324a56e1STejun Heo * Returns 0 on success, -ENOENT if such entry doesn't exist. 1607fd7b9f7bSTejun Heo */ 1608324a56e1STejun Heo int kernfs_remove_by_name_ns(struct kernfs_node *parent, const char *name, 1609fd7b9f7bSTejun Heo const void *ns) 1610fd7b9f7bSTejun Heo { 1611324a56e1STejun Heo struct kernfs_node *kn; 1612393c3714SMinchan Kim struct kernfs_root *root; 1613fd7b9f7bSTejun Heo 1614324a56e1STejun Heo if (!parent) { 1615c637b8acSTejun Heo WARN(1, KERN_WARNING "kernfs: can not remove '%s', no directory\n", 1616fd7b9f7bSTejun Heo name); 1617fd7b9f7bSTejun Heo return -ENOENT; 1618fd7b9f7bSTejun Heo } 1619fd7b9f7bSTejun Heo 1620393c3714SMinchan Kim root = kernfs_root(parent); 1621393c3714SMinchan Kim down_write(&root->kernfs_rwsem); 1622fd7b9f7bSTejun Heo 1623324a56e1STejun Heo kn = kernfs_find_ns(parent, name, ns); 1624*4abc9965SChristian A. Ehrhardt if (kn) { 1625*4abc9965SChristian A. Ehrhardt kernfs_get(kn); 1626988cd7afSTejun Heo __kernfs_remove(kn); 1627*4abc9965SChristian A. Ehrhardt kernfs_put(kn); 1628*4abc9965SChristian A. Ehrhardt } 1629fd7b9f7bSTejun Heo 1630393c3714SMinchan Kim up_write(&root->kernfs_rwsem); 1631fd7b9f7bSTejun Heo 1632324a56e1STejun Heo if (kn) 1633fd7b9f7bSTejun Heo return 0; 1634fd7b9f7bSTejun Heo else 1635fd7b9f7bSTejun Heo return -ENOENT; 1636fd7b9f7bSTejun Heo } 1637fd7b9f7bSTejun Heo 1638fd7b9f7bSTejun Heo /** 1639fd7b9f7bSTejun Heo * kernfs_rename_ns - move and rename a kernfs_node 1640324a56e1STejun Heo * @kn: target node 1641fd7b9f7bSTejun Heo * @new_parent: new parent to put @sd under 1642fd7b9f7bSTejun Heo * @new_name: new name 1643fd7b9f7bSTejun Heo * @new_ns: new namespace tag 1644fd7b9f7bSTejun Heo */ 1645324a56e1STejun Heo int kernfs_rename_ns(struct kernfs_node *kn, struct kernfs_node *new_parent, 1646fd7b9f7bSTejun Heo const char *new_name, const void *new_ns) 1647fd7b9f7bSTejun Heo { 16483eef34adSTejun Heo struct kernfs_node *old_parent; 1649393c3714SMinchan Kim struct kernfs_root *root; 16503eef34adSTejun Heo const char *old_name = NULL; 1651fd7b9f7bSTejun Heo int error; 1652fd7b9f7bSTejun Heo 16533eef34adSTejun Heo /* can't move or rename root */ 16543eef34adSTejun Heo if (!kn->parent) 16553eef34adSTejun Heo return -EINVAL; 16563eef34adSTejun Heo 1657393c3714SMinchan Kim root = kernfs_root(kn); 1658393c3714SMinchan Kim down_write(&root->kernfs_rwsem); 1659d0ae3d43STejun Heo 1660798c75a0SGreg Kroah-Hartman error = -ENOENT; 1661ea015218SEric W. Biederman if (!kernfs_active(kn) || !kernfs_active(new_parent) || 1662ea015218SEric W. Biederman (new_parent->flags & KERNFS_EMPTY_DIR)) 1663798c75a0SGreg Kroah-Hartman goto out; 1664798c75a0SGreg Kroah-Hartman 1665fd7b9f7bSTejun Heo error = 0; 1666adc5e8b5STejun Heo if ((kn->parent == new_parent) && (kn->ns == new_ns) && 1667adc5e8b5STejun Heo (strcmp(kn->name, new_name) == 0)) 1668798c75a0SGreg Kroah-Hartman goto out; /* nothing to rename */ 1669fd7b9f7bSTejun Heo 1670fd7b9f7bSTejun Heo error = -EEXIST; 1671fd7b9f7bSTejun Heo if (kernfs_find_ns(new_parent, new_name, new_ns)) 1672798c75a0SGreg Kroah-Hartman goto out; 1673fd7b9f7bSTejun Heo 1674324a56e1STejun Heo /* rename kernfs_node */ 1675adc5e8b5STejun Heo if (strcmp(kn->name, new_name) != 0) { 1676fd7b9f7bSTejun Heo error = -ENOMEM; 167775287a67SAndrzej Hajda new_name = kstrdup_const(new_name, GFP_KERNEL); 1678fd7b9f7bSTejun Heo if (!new_name) 1679798c75a0SGreg Kroah-Hartman goto out; 16803eef34adSTejun Heo } else { 16813eef34adSTejun Heo new_name = NULL; 1682fd7b9f7bSTejun Heo } 1683fd7b9f7bSTejun Heo 1684fd7b9f7bSTejun Heo /* 1685fd7b9f7bSTejun Heo * Move to the appropriate place in the appropriate directories rbtree. 1686fd7b9f7bSTejun Heo */ 1687c637b8acSTejun Heo kernfs_unlink_sibling(kn); 1688fd7b9f7bSTejun Heo kernfs_get(new_parent); 16893eef34adSTejun Heo 16903eef34adSTejun Heo /* rename_lock protects ->parent and ->name accessors */ 16913eef34adSTejun Heo spin_lock_irq(&kernfs_rename_lock); 16923eef34adSTejun Heo 16933eef34adSTejun Heo old_parent = kn->parent; 1694adc5e8b5STejun Heo kn->parent = new_parent; 16953eef34adSTejun Heo 16963eef34adSTejun Heo kn->ns = new_ns; 16973eef34adSTejun Heo if (new_name) { 16983eef34adSTejun Heo old_name = kn->name; 16993eef34adSTejun Heo kn->name = new_name; 17003eef34adSTejun Heo } 17013eef34adSTejun Heo 17023eef34adSTejun Heo spin_unlock_irq(&kernfs_rename_lock); 17033eef34adSTejun Heo 17049561a896STejun Heo kn->hash = kernfs_name_hash(kn->name, kn->ns); 1705c637b8acSTejun Heo kernfs_link_sibling(kn); 1706fd7b9f7bSTejun Heo 17073eef34adSTejun Heo kernfs_put(old_parent); 170875287a67SAndrzej Hajda kfree_const(old_name); 17093eef34adSTejun Heo 1710fd7b9f7bSTejun Heo error = 0; 1711ae34372eSTejun Heo out: 1712393c3714SMinchan Kim up_write(&root->kernfs_rwsem); 1713fd7b9f7bSTejun Heo return error; 1714fd7b9f7bSTejun Heo } 1715fd7b9f7bSTejun Heo 171621774fd8SWillem de Bruijn /* Relationship between mode and the DT_xxx types */ 1717324a56e1STejun Heo static inline unsigned char dt_type(struct kernfs_node *kn) 1718fd7b9f7bSTejun Heo { 1719adc5e8b5STejun Heo return (kn->mode >> 12) & 15; 1720fd7b9f7bSTejun Heo } 1721fd7b9f7bSTejun Heo 1722c637b8acSTejun Heo static int kernfs_dir_fop_release(struct inode *inode, struct file *filp) 1723fd7b9f7bSTejun Heo { 1724fd7b9f7bSTejun Heo kernfs_put(filp->private_data); 1725fd7b9f7bSTejun Heo return 0; 1726fd7b9f7bSTejun Heo } 1727fd7b9f7bSTejun Heo 1728c637b8acSTejun Heo static struct kernfs_node *kernfs_dir_pos(const void *ns, 1729324a56e1STejun Heo struct kernfs_node *parent, loff_t hash, struct kernfs_node *pos) 1730fd7b9f7bSTejun Heo { 1731fd7b9f7bSTejun Heo if (pos) { 173281c173cbSTejun Heo int valid = kernfs_active(pos) && 1733798c75a0SGreg Kroah-Hartman pos->parent == parent && hash == pos->hash; 1734fd7b9f7bSTejun Heo kernfs_put(pos); 1735fd7b9f7bSTejun Heo if (!valid) 1736fd7b9f7bSTejun Heo pos = NULL; 1737fd7b9f7bSTejun Heo } 1738fd7b9f7bSTejun Heo if (!pos && (hash > 1) && (hash < INT_MAX)) { 1739adc5e8b5STejun Heo struct rb_node *node = parent->dir.children.rb_node; 1740fd7b9f7bSTejun Heo while (node) { 1741324a56e1STejun Heo pos = rb_to_kn(node); 1742fd7b9f7bSTejun Heo 1743adc5e8b5STejun Heo if (hash < pos->hash) 1744fd7b9f7bSTejun Heo node = node->rb_left; 1745adc5e8b5STejun Heo else if (hash > pos->hash) 1746fd7b9f7bSTejun Heo node = node->rb_right; 1747fd7b9f7bSTejun Heo else 1748fd7b9f7bSTejun Heo break; 1749fd7b9f7bSTejun Heo } 1750fd7b9f7bSTejun Heo } 1751b9c9dad0STejun Heo /* Skip over entries which are dying/dead or in the wrong namespace */ 1752b9c9dad0STejun Heo while (pos && (!kernfs_active(pos) || pos->ns != ns)) { 1753adc5e8b5STejun Heo struct rb_node *node = rb_next(&pos->rb); 1754fd7b9f7bSTejun Heo if (!node) 1755fd7b9f7bSTejun Heo pos = NULL; 1756fd7b9f7bSTejun Heo else 1757324a56e1STejun Heo pos = rb_to_kn(node); 1758fd7b9f7bSTejun Heo } 1759fd7b9f7bSTejun Heo return pos; 1760fd7b9f7bSTejun Heo } 1761fd7b9f7bSTejun Heo 1762c637b8acSTejun Heo static struct kernfs_node *kernfs_dir_next_pos(const void *ns, 1763324a56e1STejun Heo struct kernfs_node *parent, ino_t ino, struct kernfs_node *pos) 1764fd7b9f7bSTejun Heo { 1765c637b8acSTejun Heo pos = kernfs_dir_pos(ns, parent, ino, pos); 1766b9c9dad0STejun Heo if (pos) { 1767fd7b9f7bSTejun Heo do { 1768adc5e8b5STejun Heo struct rb_node *node = rb_next(&pos->rb); 1769fd7b9f7bSTejun Heo if (!node) 1770fd7b9f7bSTejun Heo pos = NULL; 1771fd7b9f7bSTejun Heo else 1772324a56e1STejun Heo pos = rb_to_kn(node); 1773b9c9dad0STejun Heo } while (pos && (!kernfs_active(pos) || pos->ns != ns)); 1774b9c9dad0STejun Heo } 1775fd7b9f7bSTejun Heo return pos; 1776fd7b9f7bSTejun Heo } 1777fd7b9f7bSTejun Heo 1778c637b8acSTejun Heo static int kernfs_fop_readdir(struct file *file, struct dir_context *ctx) 1779fd7b9f7bSTejun Heo { 1780fd7b9f7bSTejun Heo struct dentry *dentry = file->f_path.dentry; 1781319ba91dSShaohua Li struct kernfs_node *parent = kernfs_dentry_node(dentry); 1782324a56e1STejun Heo struct kernfs_node *pos = file->private_data; 1783393c3714SMinchan Kim struct kernfs_root *root; 1784fd7b9f7bSTejun Heo const void *ns = NULL; 1785fd7b9f7bSTejun Heo 1786fd7b9f7bSTejun Heo if (!dir_emit_dots(file, ctx)) 1787fd7b9f7bSTejun Heo return 0; 1788393c3714SMinchan Kim 1789393c3714SMinchan Kim root = kernfs_root(parent); 1790393c3714SMinchan Kim down_read(&root->kernfs_rwsem); 1791fd7b9f7bSTejun Heo 1792324a56e1STejun Heo if (kernfs_ns_enabled(parent)) 1793c525aaddSTejun Heo ns = kernfs_info(dentry->d_sb)->ns; 1794fd7b9f7bSTejun Heo 1795c637b8acSTejun Heo for (pos = kernfs_dir_pos(ns, parent, ctx->pos, pos); 1796fd7b9f7bSTejun Heo pos; 1797c637b8acSTejun Heo pos = kernfs_dir_next_pos(ns, parent, ctx->pos, pos)) { 1798adc5e8b5STejun Heo const char *name = pos->name; 1799fd7b9f7bSTejun Heo unsigned int type = dt_type(pos); 1800fd7b9f7bSTejun Heo int len = strlen(name); 180167c0496eSTejun Heo ino_t ino = kernfs_ino(pos); 1802fd7b9f7bSTejun Heo 1803adc5e8b5STejun Heo ctx->pos = pos->hash; 1804fd7b9f7bSTejun Heo file->private_data = pos; 1805fd7b9f7bSTejun Heo kernfs_get(pos); 1806fd7b9f7bSTejun Heo 1807393c3714SMinchan Kim up_read(&root->kernfs_rwsem); 1808fd7b9f7bSTejun Heo if (!dir_emit(ctx, name, len, ino, type)) 1809fd7b9f7bSTejun Heo return 0; 1810393c3714SMinchan Kim down_read(&root->kernfs_rwsem); 1811fd7b9f7bSTejun Heo } 1812393c3714SMinchan Kim up_read(&root->kernfs_rwsem); 1813fd7b9f7bSTejun Heo file->private_data = NULL; 1814fd7b9f7bSTejun Heo ctx->pos = INT_MAX; 1815fd7b9f7bSTejun Heo return 0; 1816fd7b9f7bSTejun Heo } 1817fd7b9f7bSTejun Heo 1818a797bfc3STejun Heo const struct file_operations kernfs_dir_fops = { 1819fd7b9f7bSTejun Heo .read = generic_read_dir, 18208cb0d2c1SAl Viro .iterate_shared = kernfs_fop_readdir, 1821c637b8acSTejun Heo .release = kernfs_dir_fop_release, 18228cb0d2c1SAl Viro .llseek = generic_file_llseek, 1823fd7b9f7bSTejun Heo }; 1824