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 20a797bfc3STejun Heo DEFINE_MUTEX(kernfs_mutex); 213eef34adSTejun Heo static DEFINE_SPINLOCK(kernfs_rename_lock); /* kn->parent and ->name */ 223eef34adSTejun Heo static char kernfs_pr_cont_buf[PATH_MAX]; /* protected by rename_lock */ 237d35079fSShaohua Li static DEFINE_SPINLOCK(kernfs_idr_lock); /* root->ino_idr */ 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 { 4417627157SKonstantin Khlebnikov if (!kn) 4517627157SKonstantin Khlebnikov return strlcpy(buf, "(null)", buflen); 4617627157SKonstantin Khlebnikov 473eef34adSTejun Heo return strlcpy(buf, kn->parent ? kn->name : "/", buflen); 483eef34adSTejun Heo } 493eef34adSTejun Heo 509f6df573SAditya Kali /* kernfs_node_depth - compute depth from @from to @to */ 519f6df573SAditya Kali static size_t kernfs_depth(struct kernfs_node *from, struct kernfs_node *to) 523eef34adSTejun Heo { 539f6df573SAditya Kali size_t depth = 0; 543eef34adSTejun Heo 559f6df573SAditya Kali while (to->parent && to != from) { 569f6df573SAditya Kali depth++; 579f6df573SAditya Kali to = to->parent; 583eef34adSTejun Heo } 599f6df573SAditya Kali return depth; 609f6df573SAditya Kali } 613eef34adSTejun Heo 629f6df573SAditya Kali static struct kernfs_node *kernfs_common_ancestor(struct kernfs_node *a, 639f6df573SAditya Kali struct kernfs_node *b) 649f6df573SAditya Kali { 659f6df573SAditya Kali size_t da, db; 669f6df573SAditya Kali struct kernfs_root *ra = kernfs_root(a), *rb = kernfs_root(b); 679f6df573SAditya Kali 689f6df573SAditya Kali if (ra != rb) 699f6df573SAditya Kali return NULL; 709f6df573SAditya Kali 719f6df573SAditya Kali da = kernfs_depth(ra->kn, a); 729f6df573SAditya Kali db = kernfs_depth(rb->kn, b); 739f6df573SAditya Kali 749f6df573SAditya Kali while (da > db) { 759f6df573SAditya Kali a = a->parent; 769f6df573SAditya Kali da--; 779f6df573SAditya Kali } 789f6df573SAditya Kali while (db > da) { 799f6df573SAditya Kali b = b->parent; 809f6df573SAditya Kali db--; 819f6df573SAditya Kali } 829f6df573SAditya Kali 839f6df573SAditya Kali /* worst case b and a will be the same at root */ 849f6df573SAditya Kali while (b != a) { 859f6df573SAditya Kali b = b->parent; 869f6df573SAditya Kali a = a->parent; 879f6df573SAditya Kali } 889f6df573SAditya Kali 899f6df573SAditya Kali return a; 909f6df573SAditya Kali } 919f6df573SAditya Kali 929f6df573SAditya Kali /** 939f6df573SAditya Kali * kernfs_path_from_node_locked - find a pseudo-absolute path to @kn_to, 949f6df573SAditya Kali * where kn_from is treated as root of the path. 959f6df573SAditya Kali * @kn_from: kernfs node which should be treated as root for the path 969f6df573SAditya Kali * @kn_to: kernfs node to which path is needed 979f6df573SAditya Kali * @buf: buffer to copy the path into 989f6df573SAditya Kali * @buflen: size of @buf 999f6df573SAditya Kali * 1009f6df573SAditya Kali * We need to handle couple of scenarios here: 1019f6df573SAditya Kali * [1] when @kn_from is an ancestor of @kn_to at some level 1029f6df573SAditya Kali * kn_from: /n1/n2/n3 1039f6df573SAditya Kali * kn_to: /n1/n2/n3/n4/n5 1049f6df573SAditya Kali * result: /n4/n5 1059f6df573SAditya Kali * 1069f6df573SAditya Kali * [2] when @kn_from is on a different hierarchy and we need to find common 1079f6df573SAditya Kali * ancestor between @kn_from and @kn_to. 1089f6df573SAditya Kali * kn_from: /n1/n2/n3/n4 1099f6df573SAditya Kali * kn_to: /n1/n2/n5 1109f6df573SAditya Kali * result: /../../n5 1119f6df573SAditya Kali * OR 1129f6df573SAditya Kali * kn_from: /n1/n2/n3/n4/n5 [depth=5] 1139f6df573SAditya Kali * kn_to: /n1/n2/n3 [depth=3] 1149f6df573SAditya Kali * result: /../.. 1159f6df573SAditya Kali * 11617627157SKonstantin Khlebnikov * [3] when @kn_to is NULL result will be "(null)" 11717627157SKonstantin Khlebnikov * 1183abb1d90STejun Heo * Returns the length of the full path. If the full length is equal to or 1193abb1d90STejun Heo * greater than @buflen, @buf contains the truncated path with the trailing 1203abb1d90STejun Heo * '\0'. On error, -errno is returned. 1219f6df573SAditya Kali */ 1229f6df573SAditya Kali static int kernfs_path_from_node_locked(struct kernfs_node *kn_to, 1239f6df573SAditya Kali struct kernfs_node *kn_from, 1249f6df573SAditya Kali char *buf, size_t buflen) 1259f6df573SAditya Kali { 1269f6df573SAditya Kali struct kernfs_node *kn, *common; 1279f6df573SAditya Kali const char parent_str[] = "/.."; 1283abb1d90STejun Heo size_t depth_from, depth_to, len = 0; 1293abb1d90STejun Heo int i, j; 1309f6df573SAditya Kali 13117627157SKonstantin Khlebnikov if (!kn_to) 13217627157SKonstantin Khlebnikov return strlcpy(buf, "(null)", buflen); 13317627157SKonstantin Khlebnikov 1349f6df573SAditya Kali if (!kn_from) 1359f6df573SAditya Kali kn_from = kernfs_root(kn_to)->kn; 1369f6df573SAditya Kali 1379f6df573SAditya Kali if (kn_from == kn_to) 1389f6df573SAditya Kali return strlcpy(buf, "/", buflen); 1399f6df573SAditya Kali 140bbe70e4eSJia-Ju Bai if (!buf) 141bbe70e4eSJia-Ju Bai return -EINVAL; 142bbe70e4eSJia-Ju Bai 1439f6df573SAditya Kali common = kernfs_common_ancestor(kn_from, kn_to); 1449f6df573SAditya Kali if (WARN_ON(!common)) 1453abb1d90STejun Heo return -EINVAL; 1469f6df573SAditya Kali 1479f6df573SAditya Kali depth_to = kernfs_depth(common, kn_to); 1489f6df573SAditya Kali depth_from = kernfs_depth(common, kn_from); 1499f6df573SAditya Kali 1509f6df573SAditya Kali buf[0] = '\0'; 1519f6df573SAditya Kali 1529f6df573SAditya Kali for (i = 0; i < depth_from; i++) 1539f6df573SAditya Kali len += strlcpy(buf + len, parent_str, 1549f6df573SAditya Kali len < buflen ? buflen - len : 0); 1559f6df573SAditya Kali 1569f6df573SAditya Kali /* Calculate how many bytes we need for the rest */ 1573abb1d90STejun Heo for (i = depth_to - 1; i >= 0; i--) { 1583abb1d90STejun Heo for (kn = kn_to, j = 0; j < i; j++) 1593abb1d90STejun Heo kn = kn->parent; 1603abb1d90STejun Heo len += strlcpy(buf + len, "/", 1613abb1d90STejun Heo len < buflen ? buflen - len : 0); 1623abb1d90STejun Heo len += strlcpy(buf + len, kn->name, 1633abb1d90STejun Heo len < buflen ? buflen - len : 0); 1649f6df573SAditya Kali } 1659f6df573SAditya Kali 1663abb1d90STejun Heo return len; 1673eef34adSTejun Heo } 1683eef34adSTejun Heo 1693eef34adSTejun Heo /** 1703eef34adSTejun Heo * kernfs_name - obtain the name of a given node 1713eef34adSTejun Heo * @kn: kernfs_node of interest 1723eef34adSTejun Heo * @buf: buffer to copy @kn's name into 1733eef34adSTejun Heo * @buflen: size of @buf 1743eef34adSTejun Heo * 1753eef34adSTejun Heo * Copies the name of @kn into @buf of @buflen bytes. The behavior is 1763eef34adSTejun Heo * similar to strlcpy(). It returns the length of @kn's name and if @buf 1773eef34adSTejun Heo * isn't long enough, it's filled upto @buflen-1 and nul terminated. 1783eef34adSTejun Heo * 17917627157SKonstantin Khlebnikov * Fills buffer with "(null)" if @kn is NULL. 18017627157SKonstantin Khlebnikov * 1813eef34adSTejun Heo * This function can be called from any context. 1823eef34adSTejun Heo */ 1833eef34adSTejun Heo int kernfs_name(struct kernfs_node *kn, char *buf, size_t buflen) 1843eef34adSTejun Heo { 1853eef34adSTejun Heo unsigned long flags; 1863eef34adSTejun Heo int ret; 1873eef34adSTejun Heo 1883eef34adSTejun Heo spin_lock_irqsave(&kernfs_rename_lock, flags); 1893eef34adSTejun Heo ret = kernfs_name_locked(kn, buf, buflen); 1903eef34adSTejun Heo spin_unlock_irqrestore(&kernfs_rename_lock, flags); 1913eef34adSTejun Heo return ret; 1923eef34adSTejun Heo } 1933eef34adSTejun Heo 1943eef34adSTejun Heo /** 1959f6df573SAditya Kali * kernfs_path_from_node - build path of node @to relative to @from. 1969f6df573SAditya Kali * @from: parent kernfs_node relative to which we need to build the path 1979f6df573SAditya Kali * @to: kernfs_node of interest 1989f6df573SAditya Kali * @buf: buffer to copy @to's path into 1999f6df573SAditya Kali * @buflen: size of @buf 2009f6df573SAditya Kali * 2019f6df573SAditya Kali * Builds @to's path relative to @from in @buf. @from and @to must 2029f6df573SAditya Kali * be on the same kernfs-root. If @from is not parent of @to, then a relative 2039f6df573SAditya Kali * path (which includes '..'s) as needed to reach from @from to @to is 2049f6df573SAditya Kali * returned. 2059f6df573SAditya Kali * 2063abb1d90STejun Heo * Returns the length of the full path. If the full length is equal to or 2073abb1d90STejun Heo * greater than @buflen, @buf contains the truncated path with the trailing 2083abb1d90STejun Heo * '\0'. On error, -errno is returned. 2099f6df573SAditya Kali */ 2109f6df573SAditya Kali int kernfs_path_from_node(struct kernfs_node *to, struct kernfs_node *from, 2119f6df573SAditya Kali char *buf, size_t buflen) 2129f6df573SAditya Kali { 2139f6df573SAditya Kali unsigned long flags; 2149f6df573SAditya Kali int ret; 2159f6df573SAditya Kali 2169f6df573SAditya Kali spin_lock_irqsave(&kernfs_rename_lock, flags); 2179f6df573SAditya Kali ret = kernfs_path_from_node_locked(to, from, buf, buflen); 2189f6df573SAditya Kali spin_unlock_irqrestore(&kernfs_rename_lock, flags); 2199f6df573SAditya Kali return ret; 2209f6df573SAditya Kali } 2219f6df573SAditya Kali EXPORT_SYMBOL_GPL(kernfs_path_from_node); 2229f6df573SAditya Kali 2239f6df573SAditya Kali /** 2243eef34adSTejun Heo * pr_cont_kernfs_name - pr_cont name of a kernfs_node 2253eef34adSTejun Heo * @kn: kernfs_node of interest 2263eef34adSTejun Heo * 2273eef34adSTejun Heo * This function can be called from any context. 2283eef34adSTejun Heo */ 2293eef34adSTejun Heo void pr_cont_kernfs_name(struct kernfs_node *kn) 2303eef34adSTejun Heo { 2313eef34adSTejun Heo unsigned long flags; 2323eef34adSTejun Heo 2333eef34adSTejun Heo spin_lock_irqsave(&kernfs_rename_lock, flags); 2343eef34adSTejun Heo 2353eef34adSTejun Heo kernfs_name_locked(kn, kernfs_pr_cont_buf, sizeof(kernfs_pr_cont_buf)); 2363eef34adSTejun Heo pr_cont("%s", kernfs_pr_cont_buf); 2373eef34adSTejun Heo 2383eef34adSTejun Heo spin_unlock_irqrestore(&kernfs_rename_lock, flags); 2393eef34adSTejun Heo } 2403eef34adSTejun Heo 2413eef34adSTejun Heo /** 2423eef34adSTejun Heo * pr_cont_kernfs_path - pr_cont path of a kernfs_node 2433eef34adSTejun Heo * @kn: kernfs_node of interest 2443eef34adSTejun Heo * 2453eef34adSTejun Heo * This function can be called from any context. 2463eef34adSTejun Heo */ 2473eef34adSTejun Heo void pr_cont_kernfs_path(struct kernfs_node *kn) 2483eef34adSTejun Heo { 2493eef34adSTejun Heo unsigned long flags; 2509f6df573SAditya Kali int sz; 2513eef34adSTejun Heo 2523eef34adSTejun Heo spin_lock_irqsave(&kernfs_rename_lock, flags); 2533eef34adSTejun Heo 2549f6df573SAditya Kali sz = kernfs_path_from_node_locked(kn, NULL, kernfs_pr_cont_buf, 2553eef34adSTejun Heo sizeof(kernfs_pr_cont_buf)); 2569f6df573SAditya Kali if (sz < 0) { 2579f6df573SAditya Kali pr_cont("(error)"); 2589f6df573SAditya Kali goto out; 2599f6df573SAditya Kali } 2603eef34adSTejun Heo 2619f6df573SAditya Kali if (sz >= sizeof(kernfs_pr_cont_buf)) { 2629f6df573SAditya Kali pr_cont("(name too long)"); 2639f6df573SAditya Kali goto out; 2649f6df573SAditya Kali } 2659f6df573SAditya Kali 2669f6df573SAditya Kali pr_cont("%s", kernfs_pr_cont_buf); 2679f6df573SAditya Kali 2689f6df573SAditya Kali out: 2693eef34adSTejun Heo spin_unlock_irqrestore(&kernfs_rename_lock, flags); 2703eef34adSTejun Heo } 2713eef34adSTejun Heo 2723eef34adSTejun Heo /** 2733eef34adSTejun Heo * kernfs_get_parent - determine the parent node and pin it 2743eef34adSTejun Heo * @kn: kernfs_node of interest 2753eef34adSTejun Heo * 2763eef34adSTejun Heo * Determines @kn's parent, pins and returns it. This function can be 2773eef34adSTejun Heo * called from any context. 2783eef34adSTejun Heo */ 2793eef34adSTejun Heo struct kernfs_node *kernfs_get_parent(struct kernfs_node *kn) 2803eef34adSTejun Heo { 2813eef34adSTejun Heo struct kernfs_node *parent; 2823eef34adSTejun Heo unsigned long flags; 2833eef34adSTejun Heo 2843eef34adSTejun Heo spin_lock_irqsave(&kernfs_rename_lock, flags); 2853eef34adSTejun Heo parent = kn->parent; 2863eef34adSTejun Heo kernfs_get(parent); 2873eef34adSTejun Heo spin_unlock_irqrestore(&kernfs_rename_lock, flags); 2883eef34adSTejun Heo 2893eef34adSTejun Heo return parent; 2903eef34adSTejun Heo } 2913eef34adSTejun Heo 292fd7b9f7bSTejun Heo /** 293c637b8acSTejun Heo * kernfs_name_hash 294fd7b9f7bSTejun Heo * @name: Null terminated string to hash 295fd7b9f7bSTejun Heo * @ns: Namespace tag to hash 296fd7b9f7bSTejun Heo * 297fd7b9f7bSTejun Heo * Returns 31 bit hash of ns + name (so it fits in an off_t ) 298fd7b9f7bSTejun Heo */ 299c637b8acSTejun Heo static unsigned int kernfs_name_hash(const char *name, const void *ns) 300fd7b9f7bSTejun Heo { 3018387ff25SLinus Torvalds unsigned long hash = init_name_hash(ns); 302fd7b9f7bSTejun Heo unsigned int len = strlen(name); 303fd7b9f7bSTejun Heo while (len--) 304fd7b9f7bSTejun Heo hash = partial_name_hash(*name++, hash); 3058387ff25SLinus Torvalds hash = end_name_hash(hash); 306fd7b9f7bSTejun Heo hash &= 0x7fffffffU; 307fd7b9f7bSTejun Heo /* Reserve hash numbers 0, 1 and INT_MAX for magic directory entries */ 30888391d49SRichard Cochran if (hash < 2) 309fd7b9f7bSTejun Heo hash += 2; 310fd7b9f7bSTejun Heo if (hash >= INT_MAX) 311fd7b9f7bSTejun Heo hash = INT_MAX - 1; 312fd7b9f7bSTejun Heo return hash; 313fd7b9f7bSTejun Heo } 314fd7b9f7bSTejun Heo 315c637b8acSTejun Heo static int kernfs_name_compare(unsigned int hash, const char *name, 316324a56e1STejun Heo const void *ns, const struct kernfs_node *kn) 317fd7b9f7bSTejun Heo { 31872392ed0SRasmus Villemoes if (hash < kn->hash) 31972392ed0SRasmus Villemoes return -1; 32072392ed0SRasmus Villemoes if (hash > kn->hash) 32172392ed0SRasmus Villemoes return 1; 32272392ed0SRasmus Villemoes if (ns < kn->ns) 32372392ed0SRasmus Villemoes return -1; 32472392ed0SRasmus Villemoes if (ns > kn->ns) 32572392ed0SRasmus Villemoes return 1; 326adc5e8b5STejun Heo return strcmp(name, kn->name); 327fd7b9f7bSTejun Heo } 328fd7b9f7bSTejun Heo 329c637b8acSTejun Heo static int kernfs_sd_compare(const struct kernfs_node *left, 330324a56e1STejun Heo const struct kernfs_node *right) 331fd7b9f7bSTejun Heo { 332c637b8acSTejun Heo return kernfs_name_compare(left->hash, left->name, left->ns, right); 333fd7b9f7bSTejun Heo } 334fd7b9f7bSTejun Heo 335fd7b9f7bSTejun Heo /** 336c637b8acSTejun Heo * kernfs_link_sibling - link kernfs_node into sibling rbtree 337324a56e1STejun Heo * @kn: kernfs_node of interest 338fd7b9f7bSTejun Heo * 339324a56e1STejun Heo * Link @kn into its sibling rbtree which starts from 340adc5e8b5STejun Heo * @kn->parent->dir.children. 341fd7b9f7bSTejun Heo * 342fd7b9f7bSTejun Heo * Locking: 343a797bfc3STejun Heo * mutex_lock(kernfs_mutex) 344fd7b9f7bSTejun Heo * 345fd7b9f7bSTejun Heo * RETURNS: 346fd7b9f7bSTejun Heo * 0 on susccess -EEXIST on failure. 347fd7b9f7bSTejun Heo */ 348c637b8acSTejun Heo static int kernfs_link_sibling(struct kernfs_node *kn) 349fd7b9f7bSTejun Heo { 350adc5e8b5STejun Heo struct rb_node **node = &kn->parent->dir.children.rb_node; 351fd7b9f7bSTejun Heo struct rb_node *parent = NULL; 352fd7b9f7bSTejun Heo 353fd7b9f7bSTejun Heo while (*node) { 354324a56e1STejun Heo struct kernfs_node *pos; 355fd7b9f7bSTejun Heo int result; 356fd7b9f7bSTejun Heo 357324a56e1STejun Heo pos = rb_to_kn(*node); 358fd7b9f7bSTejun Heo parent = *node; 359c637b8acSTejun Heo result = kernfs_sd_compare(kn, pos); 360fd7b9f7bSTejun Heo if (result < 0) 361adc5e8b5STejun Heo node = &pos->rb.rb_left; 362fd7b9f7bSTejun Heo else if (result > 0) 363adc5e8b5STejun Heo node = &pos->rb.rb_right; 364fd7b9f7bSTejun Heo else 365fd7b9f7bSTejun Heo return -EEXIST; 366fd7b9f7bSTejun Heo } 367c1befb88SJianyu Zhan 368fd7b9f7bSTejun Heo /* add new node and rebalance the tree */ 369adc5e8b5STejun Heo rb_link_node(&kn->rb, parent, node); 370adc5e8b5STejun Heo rb_insert_color(&kn->rb, &kn->parent->dir.children); 371c1befb88SJianyu Zhan 372c1befb88SJianyu Zhan /* successfully added, account subdir number */ 373c1befb88SJianyu Zhan if (kernfs_type(kn) == KERNFS_DIR) 374c1befb88SJianyu Zhan kn->parent->dir.subdirs++; 375c1befb88SJianyu Zhan 376fd7b9f7bSTejun Heo return 0; 377fd7b9f7bSTejun Heo } 378fd7b9f7bSTejun Heo 379fd7b9f7bSTejun Heo /** 380c637b8acSTejun Heo * kernfs_unlink_sibling - unlink kernfs_node from sibling rbtree 381324a56e1STejun Heo * @kn: kernfs_node of interest 382fd7b9f7bSTejun Heo * 38335beab06STejun Heo * Try to unlink @kn from its sibling rbtree which starts from 38435beab06STejun Heo * kn->parent->dir.children. Returns %true if @kn was actually 38535beab06STejun Heo * removed, %false if @kn wasn't on the rbtree. 386fd7b9f7bSTejun Heo * 387fd7b9f7bSTejun Heo * Locking: 388a797bfc3STejun Heo * mutex_lock(kernfs_mutex) 389fd7b9f7bSTejun Heo */ 39035beab06STejun Heo static bool kernfs_unlink_sibling(struct kernfs_node *kn) 391fd7b9f7bSTejun Heo { 39235beab06STejun Heo if (RB_EMPTY_NODE(&kn->rb)) 39335beab06STejun Heo return false; 39435beab06STejun Heo 395df23fc39STejun Heo if (kernfs_type(kn) == KERNFS_DIR) 396adc5e8b5STejun Heo kn->parent->dir.subdirs--; 397fd7b9f7bSTejun Heo 398adc5e8b5STejun Heo rb_erase(&kn->rb, &kn->parent->dir.children); 39935beab06STejun Heo RB_CLEAR_NODE(&kn->rb); 40035beab06STejun Heo return true; 401fd7b9f7bSTejun Heo } 402fd7b9f7bSTejun Heo 403fd7b9f7bSTejun Heo /** 404c637b8acSTejun Heo * kernfs_get_active - get an active reference to kernfs_node 405324a56e1STejun Heo * @kn: kernfs_node to get an active reference to 406fd7b9f7bSTejun Heo * 407324a56e1STejun Heo * Get an active reference of @kn. This function is noop if @kn 408fd7b9f7bSTejun Heo * is NULL. 409fd7b9f7bSTejun Heo * 410fd7b9f7bSTejun Heo * RETURNS: 411324a56e1STejun Heo * Pointer to @kn on success, NULL on failure. 412fd7b9f7bSTejun Heo */ 413c637b8acSTejun Heo struct kernfs_node *kernfs_get_active(struct kernfs_node *kn) 414fd7b9f7bSTejun Heo { 415324a56e1STejun Heo if (unlikely(!kn)) 416fd7b9f7bSTejun Heo return NULL; 417fd7b9f7bSTejun Heo 418f4b3e631SGreg Kroah-Hartman if (!atomic_inc_unless_negative(&kn->active)) 419f4b3e631SGreg Kroah-Hartman return NULL; 420f4b3e631SGreg Kroah-Hartman 421182fd64bSTejun Heo if (kernfs_lockdep(kn)) 422324a56e1STejun Heo rwsem_acquire_read(&kn->dep_map, 0, 1, _RET_IP_); 423324a56e1STejun Heo return kn; 424fd7b9f7bSTejun Heo } 425fd7b9f7bSTejun Heo 426fd7b9f7bSTejun Heo /** 427c637b8acSTejun Heo * kernfs_put_active - put an active reference to kernfs_node 428324a56e1STejun Heo * @kn: kernfs_node to put an active reference to 429fd7b9f7bSTejun Heo * 430324a56e1STejun Heo * Put an active reference to @kn. This function is noop if @kn 431fd7b9f7bSTejun Heo * is NULL. 432fd7b9f7bSTejun Heo */ 433c637b8acSTejun Heo void kernfs_put_active(struct kernfs_node *kn) 434fd7b9f7bSTejun Heo { 435fd7b9f7bSTejun Heo int v; 436fd7b9f7bSTejun Heo 437324a56e1STejun Heo if (unlikely(!kn)) 438fd7b9f7bSTejun Heo return; 439fd7b9f7bSTejun Heo 440182fd64bSTejun Heo if (kernfs_lockdep(kn)) 4415facae4fSQian Cai rwsem_release(&kn->dep_map, _RET_IP_); 442adc5e8b5STejun Heo v = atomic_dec_return(&kn->active); 443df23fc39STejun Heo if (likely(v != KN_DEACTIVATED_BIAS)) 444fd7b9f7bSTejun Heo return; 445fd7b9f7bSTejun Heo 4462fd60da4SPeng Wang wake_up_all(&kernfs_root(kn)->deactivate_waitq); 447fd7b9f7bSTejun Heo } 448fd7b9f7bSTejun Heo 449fd7b9f7bSTejun Heo /** 45081c173cbSTejun Heo * kernfs_drain - drain kernfs_node 45181c173cbSTejun Heo * @kn: kernfs_node to drain 452fd7b9f7bSTejun Heo * 45381c173cbSTejun Heo * Drain existing usages and nuke all existing mmaps of @kn. Mutiple 45481c173cbSTejun Heo * removers may invoke this function concurrently on @kn and all will 45581c173cbSTejun Heo * return after draining is complete. 456fd7b9f7bSTejun Heo */ 45781c173cbSTejun Heo static void kernfs_drain(struct kernfs_node *kn) 45835beab06STejun Heo __releases(&kernfs_mutex) __acquires(&kernfs_mutex) 459fd7b9f7bSTejun Heo { 460abd54f02STejun Heo struct kernfs_root *root = kernfs_root(kn); 461fd7b9f7bSTejun Heo 46235beab06STejun Heo lockdep_assert_held(&kernfs_mutex); 46381c173cbSTejun Heo WARN_ON_ONCE(kernfs_active(kn)); 464abd54f02STejun Heo 46535beab06STejun Heo mutex_unlock(&kernfs_mutex); 466abd54f02STejun Heo 467182fd64bSTejun Heo if (kernfs_lockdep(kn)) { 46835beab06STejun Heo rwsem_acquire(&kn->dep_map, 0, 0, _RET_IP_); 46935beab06STejun Heo if (atomic_read(&kn->active) != KN_DEACTIVATED_BIAS) 47035beab06STejun Heo lock_contended(&kn->dep_map, _RET_IP_); 47135beab06STejun Heo } 47235beab06STejun Heo 47335beab06STejun Heo /* but everyone should wait for draining */ 474abd54f02STejun Heo wait_event(root->deactivate_waitq, 475abd54f02STejun Heo atomic_read(&kn->active) == KN_DEACTIVATED_BIAS); 476fd7b9f7bSTejun Heo 477182fd64bSTejun Heo if (kernfs_lockdep(kn)) { 478324a56e1STejun Heo lock_acquired(&kn->dep_map, _RET_IP_); 4795facae4fSQian Cai rwsem_release(&kn->dep_map, _RET_IP_); 480fd7b9f7bSTejun Heo } 48135beab06STejun Heo 4820e67db2fSTejun Heo kernfs_drain_open_files(kn); 483ccf02aafSTejun Heo 48435beab06STejun Heo mutex_lock(&kernfs_mutex); 485a6607930STejun Heo } 486fd7b9f7bSTejun Heo 487fd7b9f7bSTejun Heo /** 488324a56e1STejun Heo * kernfs_get - get a reference count on a kernfs_node 489324a56e1STejun Heo * @kn: the target kernfs_node 490fd7b9f7bSTejun Heo */ 491324a56e1STejun Heo void kernfs_get(struct kernfs_node *kn) 492fd7b9f7bSTejun Heo { 493324a56e1STejun Heo if (kn) { 494adc5e8b5STejun Heo WARN_ON(!atomic_read(&kn->count)); 495adc5e8b5STejun Heo atomic_inc(&kn->count); 496fd7b9f7bSTejun Heo } 497fd7b9f7bSTejun Heo } 498fd7b9f7bSTejun Heo EXPORT_SYMBOL_GPL(kernfs_get); 499fd7b9f7bSTejun Heo 500fd7b9f7bSTejun Heo /** 501324a56e1STejun Heo * kernfs_put - put a reference count on a kernfs_node 502324a56e1STejun Heo * @kn: the target kernfs_node 503fd7b9f7bSTejun Heo * 504324a56e1STejun Heo * Put a reference count of @kn and destroy it if it reached zero. 505fd7b9f7bSTejun Heo */ 506324a56e1STejun Heo void kernfs_put(struct kernfs_node *kn) 507fd7b9f7bSTejun Heo { 508324a56e1STejun Heo struct kernfs_node *parent; 509ba7443bcSTejun Heo struct kernfs_root *root; 510fd7b9f7bSTejun Heo 511ba16b284SShaohua Li /* 512ba16b284SShaohua Li * kernfs_node is freed with ->count 0, kernfs_find_and_get_node_by_ino 513ba16b284SShaohua Li * depends on this to filter reused stale node 514ba16b284SShaohua Li */ 515adc5e8b5STejun Heo if (!kn || !atomic_dec_and_test(&kn->count)) 516fd7b9f7bSTejun Heo return; 517324a56e1STejun Heo root = kernfs_root(kn); 518fd7b9f7bSTejun Heo repeat: 51981c173cbSTejun Heo /* 52081c173cbSTejun Heo * Moving/renaming is always done while holding reference. 521adc5e8b5STejun Heo * kn->parent won't change beneath us. 522fd7b9f7bSTejun Heo */ 523adc5e8b5STejun Heo parent = kn->parent; 524fd7b9f7bSTejun Heo 52581c173cbSTejun Heo WARN_ONCE(atomic_read(&kn->active) != KN_DEACTIVATED_BIAS, 52681c173cbSTejun Heo "kernfs_put: %s/%s: released with incorrect active_ref %d\n", 52781c173cbSTejun Heo parent ? parent->name : "", kn->name, atomic_read(&kn->active)); 528fd7b9f7bSTejun Heo 529df23fc39STejun Heo if (kernfs_type(kn) == KERNFS_LINK) 530adc5e8b5STejun Heo kernfs_put(kn->symlink.target_kn); 531dfeb0750STejun Heo 53275287a67SAndrzej Hajda kfree_const(kn->name); 533dfeb0750STejun Heo 534adc5e8b5STejun Heo if (kn->iattr) { 535adc5e8b5STejun Heo simple_xattrs_free(&kn->iattr->xattrs); 53626e28d68SAyush Mittal kmem_cache_free(kernfs_iattrs_cache, kn->iattr); 5372322392bSTejun Heo } 5387d35079fSShaohua Li spin_lock(&kernfs_idr_lock); 539c53cd490SShaohua Li idr_remove(&root->ino_idr, kn->id.ino); 5407d35079fSShaohua Li spin_unlock(&kernfs_idr_lock); 541a797bfc3STejun Heo kmem_cache_free(kernfs_node_cache, kn); 542fd7b9f7bSTejun Heo 543324a56e1STejun Heo kn = parent; 544324a56e1STejun Heo if (kn) { 545adc5e8b5STejun Heo if (atomic_dec_and_test(&kn->count)) 546fd7b9f7bSTejun Heo goto repeat; 547ba7443bcSTejun Heo } else { 548324a56e1STejun Heo /* just released the root kn, free @root too */ 5497d35079fSShaohua Li idr_destroy(&root->ino_idr); 550ba7443bcSTejun Heo kfree(root); 551ba7443bcSTejun Heo } 552fd7b9f7bSTejun Heo } 553fd7b9f7bSTejun Heo EXPORT_SYMBOL_GPL(kernfs_put); 554fd7b9f7bSTejun Heo 555c637b8acSTejun Heo static int kernfs_dop_revalidate(struct dentry *dentry, unsigned int flags) 556fd7b9f7bSTejun Heo { 557324a56e1STejun Heo struct kernfs_node *kn; 558fd7b9f7bSTejun Heo 559fd7b9f7bSTejun Heo if (flags & LOOKUP_RCU) 560fd7b9f7bSTejun Heo return -ECHILD; 561fd7b9f7bSTejun Heo 56219bbb926STejun Heo /* Always perform fresh lookup for negatives */ 5632b0143b5SDavid Howells if (d_really_is_negative(dentry)) 56419bbb926STejun Heo goto out_bad_unlocked; 56519bbb926STejun Heo 566319ba91dSShaohua Li kn = kernfs_dentry_node(dentry); 567a797bfc3STejun Heo mutex_lock(&kernfs_mutex); 568fd7b9f7bSTejun Heo 56981c173cbSTejun Heo /* The kernfs node has been deactivated */ 57081c173cbSTejun Heo if (!kernfs_active(kn)) 571fd7b9f7bSTejun Heo goto out_bad; 572fd7b9f7bSTejun Heo 573c637b8acSTejun Heo /* The kernfs node has been moved? */ 574319ba91dSShaohua Li if (kernfs_dentry_node(dentry->d_parent) != kn->parent) 575fd7b9f7bSTejun Heo goto out_bad; 576fd7b9f7bSTejun Heo 577c637b8acSTejun Heo /* The kernfs node has been renamed */ 578adc5e8b5STejun Heo if (strcmp(dentry->d_name.name, kn->name) != 0) 579fd7b9f7bSTejun Heo goto out_bad; 580fd7b9f7bSTejun Heo 581c637b8acSTejun Heo /* The kernfs node has been moved to a different namespace */ 582adc5e8b5STejun Heo if (kn->parent && kernfs_ns_enabled(kn->parent) && 583c525aaddSTejun Heo kernfs_info(dentry->d_sb)->ns != kn->ns) 584fd7b9f7bSTejun Heo goto out_bad; 585fd7b9f7bSTejun Heo 586a797bfc3STejun Heo mutex_unlock(&kernfs_mutex); 587fd7b9f7bSTejun Heo return 1; 588fd7b9f7bSTejun Heo out_bad: 589a797bfc3STejun Heo mutex_unlock(&kernfs_mutex); 59019bbb926STejun Heo out_bad_unlocked: 591fd7b9f7bSTejun Heo return 0; 592fd7b9f7bSTejun Heo } 593fd7b9f7bSTejun Heo 594a797bfc3STejun Heo const struct dentry_operations kernfs_dops = { 595c637b8acSTejun Heo .d_revalidate = kernfs_dop_revalidate, 596fd7b9f7bSTejun Heo }; 597fd7b9f7bSTejun Heo 5980c23b225STejun Heo /** 5990c23b225STejun Heo * kernfs_node_from_dentry - determine kernfs_node associated with a dentry 6000c23b225STejun Heo * @dentry: the dentry in question 6010c23b225STejun Heo * 6020c23b225STejun Heo * Return the kernfs_node associated with @dentry. If @dentry is not a 6030c23b225STejun Heo * kernfs one, %NULL is returned. 6040c23b225STejun Heo * 6050c23b225STejun Heo * While the returned kernfs_node will stay accessible as long as @dentry 6060c23b225STejun Heo * is accessible, the returned node can be in any state and the caller is 6070c23b225STejun Heo * fully responsible for determining what's accessible. 6080c23b225STejun Heo */ 6090c23b225STejun Heo struct kernfs_node *kernfs_node_from_dentry(struct dentry *dentry) 6100c23b225STejun Heo { 611319ba91dSShaohua Li if (dentry->d_sb->s_op == &kernfs_sops && 612319ba91dSShaohua Li !d_really_is_negative(dentry)) 613319ba91dSShaohua Li return kernfs_dentry_node(dentry); 6140c23b225STejun Heo return NULL; 6150c23b225STejun Heo } 6160c23b225STejun Heo 617db4aad20STejun Heo static struct kernfs_node *__kernfs_new_node(struct kernfs_root *root, 618e19dfdc8SOndrej Mosnacek struct kernfs_node *parent, 619db4aad20STejun Heo const char *name, umode_t mode, 620488dee96SDmitry Torokhov kuid_t uid, kgid_t gid, 621db4aad20STejun Heo unsigned flags) 622fd7b9f7bSTejun Heo { 623324a56e1STejun Heo struct kernfs_node *kn; 6244a3ef68aSShaohua Li u32 gen; 6254a3ef68aSShaohua Li int cursor; 626bc755553STejun Heo int ret; 627fd7b9f7bSTejun Heo 628dfeb0750STejun Heo name = kstrdup_const(name, GFP_KERNEL); 629fd7b9f7bSTejun Heo if (!name) 630fd7b9f7bSTejun Heo return NULL; 631fd7b9f7bSTejun Heo 632a797bfc3STejun Heo kn = kmem_cache_zalloc(kernfs_node_cache, GFP_KERNEL); 633324a56e1STejun Heo if (!kn) 634fd7b9f7bSTejun Heo goto err_out1; 635fd7b9f7bSTejun Heo 6367d35079fSShaohua Li idr_preload(GFP_KERNEL); 6377d35079fSShaohua Li spin_lock(&kernfs_idr_lock); 6384a3ef68aSShaohua Li cursor = idr_get_cursor(&root->ino_idr); 6394a3ef68aSShaohua Li ret = idr_alloc_cyclic(&root->ino_idr, kn, 1, 0, GFP_ATOMIC); 6404a3ef68aSShaohua Li if (ret >= 0 && ret < cursor) 6414a3ef68aSShaohua Li root->next_generation++; 6424a3ef68aSShaohua Li gen = root->next_generation; 6437d35079fSShaohua Li spin_unlock(&kernfs_idr_lock); 6447d35079fSShaohua Li idr_preload_end(); 645bc755553STejun Heo if (ret < 0) 646fd7b9f7bSTejun Heo goto err_out2; 647c53cd490SShaohua Li kn->id.ino = ret; 648c53cd490SShaohua Li kn->id.generation = gen; 649fd7b9f7bSTejun Heo 650ba16b284SShaohua Li /* 65199826790SAndrea Parri * set ino first. This RELEASE is paired with atomic_inc_not_zero in 652ba16b284SShaohua Li * kernfs_find_and_get_node_by_ino 653ba16b284SShaohua Li */ 65499826790SAndrea Parri atomic_set_release(&kn->count, 1); 65581c173cbSTejun Heo atomic_set(&kn->active, KN_DEACTIVATED_BIAS); 65635beab06STejun Heo RB_CLEAR_NODE(&kn->rb); 657fd7b9f7bSTejun Heo 658adc5e8b5STejun Heo kn->name = name; 659adc5e8b5STejun Heo kn->mode = mode; 66081c173cbSTejun Heo kn->flags = flags; 661fd7b9f7bSTejun Heo 662488dee96SDmitry Torokhov if (!uid_eq(uid, GLOBAL_ROOT_UID) || !gid_eq(gid, GLOBAL_ROOT_GID)) { 663488dee96SDmitry Torokhov struct iattr iattr = { 664488dee96SDmitry Torokhov .ia_valid = ATTR_UID | ATTR_GID, 665488dee96SDmitry Torokhov .ia_uid = uid, 666488dee96SDmitry Torokhov .ia_gid = gid, 667488dee96SDmitry Torokhov }; 668488dee96SDmitry Torokhov 669488dee96SDmitry Torokhov ret = __kernfs_setattr(kn, &iattr); 670488dee96SDmitry Torokhov if (ret < 0) 671488dee96SDmitry Torokhov goto err_out3; 672488dee96SDmitry Torokhov } 673488dee96SDmitry Torokhov 674e19dfdc8SOndrej Mosnacek if (parent) { 675e19dfdc8SOndrej Mosnacek ret = security_kernfs_init_security(parent, kn); 676e19dfdc8SOndrej Mosnacek if (ret) 677e19dfdc8SOndrej Mosnacek goto err_out3; 678e19dfdc8SOndrej Mosnacek } 679e19dfdc8SOndrej Mosnacek 680324a56e1STejun Heo return kn; 681fd7b9f7bSTejun Heo 682488dee96SDmitry Torokhov err_out3: 683488dee96SDmitry Torokhov idr_remove(&root->ino_idr, kn->id.ino); 684fd7b9f7bSTejun Heo err_out2: 685a797bfc3STejun Heo kmem_cache_free(kernfs_node_cache, kn); 686fd7b9f7bSTejun Heo err_out1: 687dfeb0750STejun Heo kfree_const(name); 688fd7b9f7bSTejun Heo return NULL; 689fd7b9f7bSTejun Heo } 690fd7b9f7bSTejun Heo 691db4aad20STejun Heo struct kernfs_node *kernfs_new_node(struct kernfs_node *parent, 692db4aad20STejun Heo const char *name, umode_t mode, 693488dee96SDmitry Torokhov kuid_t uid, kgid_t gid, 694db4aad20STejun Heo unsigned flags) 695db4aad20STejun Heo { 696db4aad20STejun Heo struct kernfs_node *kn; 697db4aad20STejun Heo 698e19dfdc8SOndrej Mosnacek kn = __kernfs_new_node(kernfs_root(parent), parent, 699488dee96SDmitry Torokhov name, mode, uid, gid, flags); 700db4aad20STejun Heo if (kn) { 701db4aad20STejun Heo kernfs_get(parent); 702db4aad20STejun Heo kn->parent = parent; 703db4aad20STejun Heo } 704db4aad20STejun Heo return kn; 705db4aad20STejun Heo } 706db4aad20STejun Heo 707ba16b284SShaohua Li /* 708ba16b284SShaohua Li * kernfs_find_and_get_node_by_ino - get kernfs_node from inode number 709ba16b284SShaohua Li * @root: the kernfs root 710ba16b284SShaohua Li * @ino: inode number 711ba16b284SShaohua Li * 712ba16b284SShaohua Li * RETURNS: 713ba16b284SShaohua Li * NULL on failure. Return a kernfs node with reference counter incremented 714ba16b284SShaohua Li */ 715ba16b284SShaohua Li struct kernfs_node *kernfs_find_and_get_node_by_ino(struct kernfs_root *root, 716ba16b284SShaohua Li unsigned int ino) 717ba16b284SShaohua Li { 718ba16b284SShaohua Li struct kernfs_node *kn; 719ba16b284SShaohua Li 720ba16b284SShaohua Li rcu_read_lock(); 721ba16b284SShaohua Li kn = idr_find(&root->ino_idr, ino); 722ba16b284SShaohua Li if (!kn) 723ba16b284SShaohua Li goto out; 724ba16b284SShaohua Li 725ba16b284SShaohua Li /* 726ba16b284SShaohua Li * Since kernfs_node is freed in RCU, it's possible an old node for ino 727ba16b284SShaohua Li * is freed, but reused before RCU grace period. But a freed node (see 728ba16b284SShaohua Li * kernfs_put) or an incompletedly initialized node (see 729ba16b284SShaohua Li * __kernfs_new_node) should have 'count' 0. We can use this fact to 730ba16b284SShaohua Li * filter out such node. 731ba16b284SShaohua Li */ 732ba16b284SShaohua Li if (!atomic_inc_not_zero(&kn->count)) { 733ba16b284SShaohua Li kn = NULL; 734ba16b284SShaohua Li goto out; 735ba16b284SShaohua Li } 736ba16b284SShaohua Li 737ba16b284SShaohua Li /* 738ba16b284SShaohua Li * The node could be a new node or a reused node. If it's a new node, 739ba16b284SShaohua Li * we are ok. If it's reused because of RCU (because of 740ba16b284SShaohua Li * SLAB_TYPESAFE_BY_RCU), the __kernfs_new_node always sets its 'ino' 741ba16b284SShaohua Li * before 'count'. So if 'count' is uptodate, 'ino' should be uptodate, 742ba16b284SShaohua Li * hence we can use 'ino' to filter stale node. 743ba16b284SShaohua Li */ 744c53cd490SShaohua Li if (kn->id.ino != ino) 745ba16b284SShaohua Li goto out; 746ba16b284SShaohua Li rcu_read_unlock(); 747ba16b284SShaohua Li 748ba16b284SShaohua Li return kn; 749ba16b284SShaohua Li out: 750ba16b284SShaohua Li rcu_read_unlock(); 751ba16b284SShaohua Li kernfs_put(kn); 752ba16b284SShaohua Li return NULL; 753ba16b284SShaohua Li } 754ba16b284SShaohua Li 755fd7b9f7bSTejun Heo /** 756c637b8acSTejun Heo * kernfs_add_one - add kernfs_node to parent without warning 757324a56e1STejun Heo * @kn: kernfs_node to be added 758fd7b9f7bSTejun Heo * 759db4aad20STejun Heo * The caller must already have initialized @kn->parent. This 760db4aad20STejun Heo * function increments nlink of the parent's inode if @kn is a 761db4aad20STejun Heo * directory and link into the children list of the parent. 762fd7b9f7bSTejun Heo * 763fd7b9f7bSTejun Heo * RETURNS: 764fd7b9f7bSTejun Heo * 0 on success, -EEXIST if entry with the given name already 765fd7b9f7bSTejun Heo * exists. 766fd7b9f7bSTejun Heo */ 767988cd7afSTejun Heo int kernfs_add_one(struct kernfs_node *kn) 768fd7b9f7bSTejun Heo { 769db4aad20STejun Heo struct kernfs_node *parent = kn->parent; 770c525aaddSTejun Heo struct kernfs_iattrs *ps_iattr; 771988cd7afSTejun Heo bool has_ns; 772fd7b9f7bSTejun Heo int ret; 773fd7b9f7bSTejun Heo 774988cd7afSTejun Heo mutex_lock(&kernfs_mutex); 775988cd7afSTejun Heo 776988cd7afSTejun Heo ret = -EINVAL; 777988cd7afSTejun Heo has_ns = kernfs_ns_enabled(parent); 778988cd7afSTejun Heo if (WARN(has_ns != (bool)kn->ns, KERN_WARNING "kernfs: ns %s in '%s' for '%s'\n", 779988cd7afSTejun Heo has_ns ? "required" : "invalid", parent->name, kn->name)) 780988cd7afSTejun Heo goto out_unlock; 781fd7b9f7bSTejun Heo 782df23fc39STejun Heo if (kernfs_type(parent) != KERNFS_DIR) 783988cd7afSTejun Heo goto out_unlock; 784fd7b9f7bSTejun Heo 785988cd7afSTejun Heo ret = -ENOENT; 786ea015218SEric W. Biederman if (parent->flags & KERNFS_EMPTY_DIR) 787ea015218SEric W. Biederman goto out_unlock; 788ea015218SEric W. Biederman 789d35258efSTejun Heo if ((parent->flags & KERNFS_ACTIVATED) && !kernfs_active(parent)) 790988cd7afSTejun Heo goto out_unlock; 791798c75a0SGreg Kroah-Hartman 792c637b8acSTejun Heo kn->hash = kernfs_name_hash(kn->name, kn->ns); 793fd7b9f7bSTejun Heo 794c637b8acSTejun Heo ret = kernfs_link_sibling(kn); 795fd7b9f7bSTejun Heo if (ret) 796988cd7afSTejun Heo goto out_unlock; 797fd7b9f7bSTejun Heo 798fd7b9f7bSTejun Heo /* Update timestamps on the parent */ 799adc5e8b5STejun Heo ps_iattr = parent->iattr; 800fd7b9f7bSTejun Heo if (ps_iattr) { 80105895219SOndrej Mosnacek ktime_get_real_ts64(&ps_iattr->ia_ctime); 80205895219SOndrej Mosnacek ps_iattr->ia_mtime = ps_iattr->ia_ctime; 803fd7b9f7bSTejun Heo } 804fd7b9f7bSTejun Heo 805d35258efSTejun Heo mutex_unlock(&kernfs_mutex); 806d35258efSTejun Heo 807d35258efSTejun Heo /* 808d35258efSTejun Heo * Activate the new node unless CREATE_DEACTIVATED is requested. 809d35258efSTejun Heo * If not activated here, the kernfs user is responsible for 810d35258efSTejun Heo * activating the node with kernfs_activate(). A node which hasn't 811d35258efSTejun Heo * been activated is not visible to userland and its removal won't 812d35258efSTejun Heo * trigger deactivation. 813d35258efSTejun Heo */ 814d35258efSTejun Heo if (!(kernfs_root(kn)->flags & KERNFS_ROOT_CREATE_DEACTIVATED)) 815d35258efSTejun Heo kernfs_activate(kn); 816d35258efSTejun Heo return 0; 817d35258efSTejun Heo 818988cd7afSTejun Heo out_unlock: 819a797bfc3STejun Heo mutex_unlock(&kernfs_mutex); 820988cd7afSTejun Heo return ret; 821fd7b9f7bSTejun Heo } 822fd7b9f7bSTejun Heo 823fd7b9f7bSTejun Heo /** 824324a56e1STejun Heo * kernfs_find_ns - find kernfs_node with the given name 825324a56e1STejun Heo * @parent: kernfs_node to search under 826fd7b9f7bSTejun Heo * @name: name to look for 827fd7b9f7bSTejun Heo * @ns: the namespace tag to use 828fd7b9f7bSTejun Heo * 829324a56e1STejun Heo * Look for kernfs_node with name @name under @parent. Returns pointer to 830324a56e1STejun Heo * the found kernfs_node on success, %NULL on failure. 831fd7b9f7bSTejun Heo */ 832324a56e1STejun Heo static struct kernfs_node *kernfs_find_ns(struct kernfs_node *parent, 833fd7b9f7bSTejun Heo const unsigned char *name, 834fd7b9f7bSTejun Heo const void *ns) 835fd7b9f7bSTejun Heo { 836adc5e8b5STejun Heo struct rb_node *node = parent->dir.children.rb_node; 837ac9bba03STejun Heo bool has_ns = kernfs_ns_enabled(parent); 838fd7b9f7bSTejun Heo unsigned int hash; 839fd7b9f7bSTejun Heo 840a797bfc3STejun Heo lockdep_assert_held(&kernfs_mutex); 841fd7b9f7bSTejun Heo 842fd7b9f7bSTejun Heo if (has_ns != (bool)ns) { 843c637b8acSTejun Heo WARN(1, KERN_WARNING "kernfs: ns %s in '%s' for '%s'\n", 844adc5e8b5STejun Heo has_ns ? "required" : "invalid", parent->name, name); 845fd7b9f7bSTejun Heo return NULL; 846fd7b9f7bSTejun Heo } 847fd7b9f7bSTejun Heo 848c637b8acSTejun Heo hash = kernfs_name_hash(name, ns); 849fd7b9f7bSTejun Heo while (node) { 850324a56e1STejun Heo struct kernfs_node *kn; 851fd7b9f7bSTejun Heo int result; 852fd7b9f7bSTejun Heo 853324a56e1STejun Heo kn = rb_to_kn(node); 854c637b8acSTejun Heo result = kernfs_name_compare(hash, name, ns, kn); 855fd7b9f7bSTejun Heo if (result < 0) 856fd7b9f7bSTejun Heo node = node->rb_left; 857fd7b9f7bSTejun Heo else if (result > 0) 858fd7b9f7bSTejun Heo node = node->rb_right; 859fd7b9f7bSTejun Heo else 860324a56e1STejun Heo return kn; 861fd7b9f7bSTejun Heo } 862fd7b9f7bSTejun Heo return NULL; 863fd7b9f7bSTejun Heo } 864fd7b9f7bSTejun Heo 865bd96f76aSTejun Heo static struct kernfs_node *kernfs_walk_ns(struct kernfs_node *parent, 866bd96f76aSTejun Heo const unsigned char *path, 867bd96f76aSTejun Heo const void *ns) 868bd96f76aSTejun Heo { 869e56ed358STejun Heo size_t len; 870e56ed358STejun Heo char *p, *name; 871bd96f76aSTejun Heo 872bd96f76aSTejun Heo lockdep_assert_held(&kernfs_mutex); 873bd96f76aSTejun Heo 874e56ed358STejun Heo /* grab kernfs_rename_lock to piggy back on kernfs_pr_cont_buf */ 875e56ed358STejun Heo spin_lock_irq(&kernfs_rename_lock); 876e56ed358STejun Heo 877e56ed358STejun Heo len = strlcpy(kernfs_pr_cont_buf, path, sizeof(kernfs_pr_cont_buf)); 878e56ed358STejun Heo 879e56ed358STejun Heo if (len >= sizeof(kernfs_pr_cont_buf)) { 880e56ed358STejun Heo spin_unlock_irq(&kernfs_rename_lock); 881bd96f76aSTejun Heo return NULL; 882e56ed358STejun Heo } 883e56ed358STejun Heo 884e56ed358STejun Heo p = kernfs_pr_cont_buf; 885bd96f76aSTejun Heo 886bd96f76aSTejun Heo while ((name = strsep(&p, "/")) && parent) { 887bd96f76aSTejun Heo if (*name == '\0') 888bd96f76aSTejun Heo continue; 889bd96f76aSTejun Heo parent = kernfs_find_ns(parent, name, ns); 890bd96f76aSTejun Heo } 891bd96f76aSTejun Heo 892e56ed358STejun Heo spin_unlock_irq(&kernfs_rename_lock); 893e56ed358STejun Heo 894bd96f76aSTejun Heo return parent; 895bd96f76aSTejun Heo } 896bd96f76aSTejun Heo 897fd7b9f7bSTejun Heo /** 898324a56e1STejun Heo * kernfs_find_and_get_ns - find and get kernfs_node with the given name 899324a56e1STejun Heo * @parent: kernfs_node to search under 900fd7b9f7bSTejun Heo * @name: name to look for 901fd7b9f7bSTejun Heo * @ns: the namespace tag to use 902fd7b9f7bSTejun Heo * 903324a56e1STejun Heo * Look for kernfs_node with name @name under @parent and get a reference 904fd7b9f7bSTejun Heo * if found. This function may sleep and returns pointer to the found 905324a56e1STejun Heo * kernfs_node on success, %NULL on failure. 906fd7b9f7bSTejun Heo */ 907324a56e1STejun Heo struct kernfs_node *kernfs_find_and_get_ns(struct kernfs_node *parent, 908fd7b9f7bSTejun Heo const char *name, const void *ns) 909fd7b9f7bSTejun Heo { 910324a56e1STejun Heo struct kernfs_node *kn; 911fd7b9f7bSTejun Heo 912a797bfc3STejun Heo mutex_lock(&kernfs_mutex); 913324a56e1STejun Heo kn = kernfs_find_ns(parent, name, ns); 914324a56e1STejun Heo kernfs_get(kn); 915a797bfc3STejun Heo mutex_unlock(&kernfs_mutex); 916fd7b9f7bSTejun Heo 917324a56e1STejun Heo return kn; 918fd7b9f7bSTejun Heo } 919fd7b9f7bSTejun Heo EXPORT_SYMBOL_GPL(kernfs_find_and_get_ns); 920fd7b9f7bSTejun Heo 921fd7b9f7bSTejun Heo /** 922bd96f76aSTejun Heo * kernfs_walk_and_get_ns - find and get kernfs_node with the given path 923bd96f76aSTejun Heo * @parent: kernfs_node to search under 924bd96f76aSTejun Heo * @path: path to look for 925bd96f76aSTejun Heo * @ns: the namespace tag to use 926bd96f76aSTejun Heo * 927bd96f76aSTejun Heo * Look for kernfs_node with path @path under @parent and get a reference 928bd96f76aSTejun Heo * if found. This function may sleep and returns pointer to the found 929bd96f76aSTejun Heo * kernfs_node on success, %NULL on failure. 930bd96f76aSTejun Heo */ 931bd96f76aSTejun Heo struct kernfs_node *kernfs_walk_and_get_ns(struct kernfs_node *parent, 932bd96f76aSTejun Heo const char *path, const void *ns) 933bd96f76aSTejun Heo { 934bd96f76aSTejun Heo struct kernfs_node *kn; 935bd96f76aSTejun Heo 936bd96f76aSTejun Heo mutex_lock(&kernfs_mutex); 937bd96f76aSTejun Heo kn = kernfs_walk_ns(parent, path, ns); 938bd96f76aSTejun Heo kernfs_get(kn); 939bd96f76aSTejun Heo mutex_unlock(&kernfs_mutex); 940bd96f76aSTejun Heo 941bd96f76aSTejun Heo return kn; 942bd96f76aSTejun Heo } 943bd96f76aSTejun Heo 944bd96f76aSTejun Heo /** 945ba7443bcSTejun Heo * kernfs_create_root - create a new kernfs hierarchy 94690c07c89STejun Heo * @scops: optional syscall operations for the hierarchy 947d35258efSTejun Heo * @flags: KERNFS_ROOT_* flags 948ba7443bcSTejun Heo * @priv: opaque data associated with the new directory 949ba7443bcSTejun Heo * 950ba7443bcSTejun Heo * Returns the root of the new hierarchy on success, ERR_PTR() value on 951ba7443bcSTejun Heo * failure. 952ba7443bcSTejun Heo */ 95390c07c89STejun Heo struct kernfs_root *kernfs_create_root(struct kernfs_syscall_ops *scops, 954d35258efSTejun Heo unsigned int flags, void *priv) 955ba7443bcSTejun Heo { 956ba7443bcSTejun Heo struct kernfs_root *root; 957324a56e1STejun Heo struct kernfs_node *kn; 958ba7443bcSTejun Heo 959ba7443bcSTejun Heo root = kzalloc(sizeof(*root), GFP_KERNEL); 960ba7443bcSTejun Heo if (!root) 961ba7443bcSTejun Heo return ERR_PTR(-ENOMEM); 962ba7443bcSTejun Heo 9637d35079fSShaohua Li idr_init(&root->ino_idr); 9647d568a83STejun Heo INIT_LIST_HEAD(&root->supers); 9654a3ef68aSShaohua Li root->next_generation = 1; 966bc755553STejun Heo 967e19dfdc8SOndrej Mosnacek kn = __kernfs_new_node(root, NULL, "", S_IFDIR | S_IRUGO | S_IXUGO, 968488dee96SDmitry Torokhov GLOBAL_ROOT_UID, GLOBAL_ROOT_GID, 969db4aad20STejun Heo KERNFS_DIR); 970324a56e1STejun Heo if (!kn) { 9717d35079fSShaohua Li idr_destroy(&root->ino_idr); 972ba7443bcSTejun Heo kfree(root); 973ba7443bcSTejun Heo return ERR_PTR(-ENOMEM); 974ba7443bcSTejun Heo } 975ba7443bcSTejun Heo 976324a56e1STejun Heo kn->priv = priv; 977adc5e8b5STejun Heo kn->dir.root = root; 978ba7443bcSTejun Heo 97990c07c89STejun Heo root->syscall_ops = scops; 980d35258efSTejun Heo root->flags = flags; 981324a56e1STejun Heo root->kn = kn; 982abd54f02STejun Heo init_waitqueue_head(&root->deactivate_waitq); 983ba7443bcSTejun Heo 984d35258efSTejun Heo if (!(root->flags & KERNFS_ROOT_CREATE_DEACTIVATED)) 985d35258efSTejun Heo kernfs_activate(kn); 986d35258efSTejun Heo 987ba7443bcSTejun Heo return root; 988ba7443bcSTejun Heo } 989ba7443bcSTejun Heo 990ba7443bcSTejun Heo /** 991ba7443bcSTejun Heo * kernfs_destroy_root - destroy a kernfs hierarchy 992ba7443bcSTejun Heo * @root: root of the hierarchy to destroy 993ba7443bcSTejun Heo * 994ba7443bcSTejun Heo * Destroy the hierarchy anchored at @root by removing all existing 995ba7443bcSTejun Heo * directories and destroying @root. 996ba7443bcSTejun Heo */ 997ba7443bcSTejun Heo void kernfs_destroy_root(struct kernfs_root *root) 998ba7443bcSTejun Heo { 999324a56e1STejun Heo kernfs_remove(root->kn); /* will also free @root */ 1000ba7443bcSTejun Heo } 1001ba7443bcSTejun Heo 1002ba7443bcSTejun Heo /** 1003fd7b9f7bSTejun Heo * kernfs_create_dir_ns - create a directory 1004fd7b9f7bSTejun Heo * @parent: parent in which to create a new directory 1005fd7b9f7bSTejun Heo * @name: name of the new directory 1006bb8b9d09STejun Heo * @mode: mode of the new directory 1007488dee96SDmitry Torokhov * @uid: uid of the new directory 1008488dee96SDmitry Torokhov * @gid: gid of the new directory 1009fd7b9f7bSTejun Heo * @priv: opaque data associated with the new directory 1010fd7b9f7bSTejun Heo * @ns: optional namespace tag of the directory 1011fd7b9f7bSTejun Heo * 1012fd7b9f7bSTejun Heo * Returns the created node on success, ERR_PTR() value on failure. 1013fd7b9f7bSTejun Heo */ 1014324a56e1STejun Heo struct kernfs_node *kernfs_create_dir_ns(struct kernfs_node *parent, 1015bb8b9d09STejun Heo const char *name, umode_t mode, 1016488dee96SDmitry Torokhov kuid_t uid, kgid_t gid, 1017bb8b9d09STejun Heo void *priv, const void *ns) 1018fd7b9f7bSTejun Heo { 1019324a56e1STejun Heo struct kernfs_node *kn; 1020fd7b9f7bSTejun Heo int rc; 1021fd7b9f7bSTejun Heo 1022fd7b9f7bSTejun Heo /* allocate */ 1023488dee96SDmitry Torokhov kn = kernfs_new_node(parent, name, mode | S_IFDIR, 1024488dee96SDmitry Torokhov uid, gid, KERNFS_DIR); 1025324a56e1STejun Heo if (!kn) 1026fd7b9f7bSTejun Heo return ERR_PTR(-ENOMEM); 1027fd7b9f7bSTejun Heo 1028adc5e8b5STejun Heo kn->dir.root = parent->dir.root; 1029adc5e8b5STejun Heo kn->ns = ns; 1030324a56e1STejun Heo kn->priv = priv; 1031fd7b9f7bSTejun Heo 1032fd7b9f7bSTejun Heo /* link in */ 1033988cd7afSTejun Heo rc = kernfs_add_one(kn); 1034fd7b9f7bSTejun Heo if (!rc) 1035324a56e1STejun Heo return kn; 1036fd7b9f7bSTejun Heo 1037324a56e1STejun Heo kernfs_put(kn); 1038fd7b9f7bSTejun Heo return ERR_PTR(rc); 1039fd7b9f7bSTejun Heo } 1040fd7b9f7bSTejun Heo 1041ea015218SEric W. Biederman /** 1042ea015218SEric W. Biederman * kernfs_create_empty_dir - create an always empty directory 1043ea015218SEric W. Biederman * @parent: parent in which to create a new directory 1044ea015218SEric W. Biederman * @name: name of the new directory 1045ea015218SEric W. Biederman * 1046ea015218SEric W. Biederman * Returns the created node on success, ERR_PTR() value on failure. 1047ea015218SEric W. Biederman */ 1048ea015218SEric W. Biederman struct kernfs_node *kernfs_create_empty_dir(struct kernfs_node *parent, 1049ea015218SEric W. Biederman const char *name) 1050ea015218SEric W. Biederman { 1051ea015218SEric W. Biederman struct kernfs_node *kn; 1052ea015218SEric W. Biederman int rc; 1053ea015218SEric W. Biederman 1054ea015218SEric W. Biederman /* allocate */ 1055488dee96SDmitry Torokhov kn = kernfs_new_node(parent, name, S_IRUGO|S_IXUGO|S_IFDIR, 1056488dee96SDmitry Torokhov GLOBAL_ROOT_UID, GLOBAL_ROOT_GID, KERNFS_DIR); 1057ea015218SEric W. Biederman if (!kn) 1058ea015218SEric W. Biederman return ERR_PTR(-ENOMEM); 1059ea015218SEric W. Biederman 1060ea015218SEric W. Biederman kn->flags |= KERNFS_EMPTY_DIR; 1061ea015218SEric W. Biederman kn->dir.root = parent->dir.root; 1062ea015218SEric W. Biederman kn->ns = NULL; 1063ea015218SEric W. Biederman kn->priv = NULL; 1064ea015218SEric W. Biederman 1065ea015218SEric W. Biederman /* link in */ 1066ea015218SEric W. Biederman rc = kernfs_add_one(kn); 1067ea015218SEric W. Biederman if (!rc) 1068ea015218SEric W. Biederman return kn; 1069ea015218SEric W. Biederman 1070ea015218SEric W. Biederman kernfs_put(kn); 1071ea015218SEric W. Biederman return ERR_PTR(rc); 1072ea015218SEric W. Biederman } 1073ea015218SEric W. Biederman 1074c637b8acSTejun Heo static struct dentry *kernfs_iop_lookup(struct inode *dir, 1075c637b8acSTejun Heo struct dentry *dentry, 1076fd7b9f7bSTejun Heo unsigned int flags) 1077fd7b9f7bSTejun Heo { 107819bbb926STejun Heo struct dentry *ret; 1079319ba91dSShaohua Li struct kernfs_node *parent = dir->i_private; 1080324a56e1STejun Heo struct kernfs_node *kn; 1081fd7b9f7bSTejun Heo struct inode *inode; 1082fd7b9f7bSTejun Heo const void *ns = NULL; 1083fd7b9f7bSTejun Heo 1084a797bfc3STejun Heo mutex_lock(&kernfs_mutex); 1085fd7b9f7bSTejun Heo 1086324a56e1STejun Heo if (kernfs_ns_enabled(parent)) 1087c525aaddSTejun Heo ns = kernfs_info(dir->i_sb)->ns; 1088fd7b9f7bSTejun Heo 1089324a56e1STejun Heo kn = kernfs_find_ns(parent, dentry->d_name.name, ns); 1090fd7b9f7bSTejun Heo 1091fd7b9f7bSTejun Heo /* no such entry */ 1092b9c9dad0STejun Heo if (!kn || !kernfs_active(kn)) { 109319bbb926STejun Heo ret = NULL; 1094fd7b9f7bSTejun Heo goto out_unlock; 1095fd7b9f7bSTejun Heo } 1096fd7b9f7bSTejun Heo 1097fd7b9f7bSTejun Heo /* attach dentry and inode */ 1098c637b8acSTejun Heo inode = kernfs_get_inode(dir->i_sb, kn); 1099fd7b9f7bSTejun Heo if (!inode) { 1100fd7b9f7bSTejun Heo ret = ERR_PTR(-ENOMEM); 1101fd7b9f7bSTejun Heo goto out_unlock; 1102fd7b9f7bSTejun Heo } 1103fd7b9f7bSTejun Heo 1104fd7b9f7bSTejun Heo /* instantiate and hash dentry */ 110541d28bcaSAl Viro ret = d_splice_alias(inode, dentry); 1106fd7b9f7bSTejun Heo out_unlock: 1107a797bfc3STejun Heo mutex_unlock(&kernfs_mutex); 1108fd7b9f7bSTejun Heo return ret; 1109fd7b9f7bSTejun Heo } 1110fd7b9f7bSTejun Heo 111180b9bbefSTejun Heo static int kernfs_iop_mkdir(struct inode *dir, struct dentry *dentry, 111280b9bbefSTejun Heo umode_t mode) 111380b9bbefSTejun Heo { 111480b9bbefSTejun Heo struct kernfs_node *parent = dir->i_private; 111590c07c89STejun Heo struct kernfs_syscall_ops *scops = kernfs_root(parent)->syscall_ops; 111607c7530dSTejun Heo int ret; 111780b9bbefSTejun Heo 111890c07c89STejun Heo if (!scops || !scops->mkdir) 111980b9bbefSTejun Heo return -EPERM; 112080b9bbefSTejun Heo 112107c7530dSTejun Heo if (!kernfs_get_active(parent)) 112207c7530dSTejun Heo return -ENODEV; 112307c7530dSTejun Heo 112490c07c89STejun Heo ret = scops->mkdir(parent, dentry->d_name.name, mode); 112507c7530dSTejun Heo 112607c7530dSTejun Heo kernfs_put_active(parent); 112707c7530dSTejun Heo return ret; 112880b9bbefSTejun Heo } 112980b9bbefSTejun Heo 113080b9bbefSTejun Heo static int kernfs_iop_rmdir(struct inode *dir, struct dentry *dentry) 113180b9bbefSTejun Heo { 1132319ba91dSShaohua Li struct kernfs_node *kn = kernfs_dentry_node(dentry); 113390c07c89STejun Heo struct kernfs_syscall_ops *scops = kernfs_root(kn)->syscall_ops; 113407c7530dSTejun Heo int ret; 113580b9bbefSTejun Heo 113690c07c89STejun Heo if (!scops || !scops->rmdir) 113780b9bbefSTejun Heo return -EPERM; 113880b9bbefSTejun Heo 113907c7530dSTejun Heo if (!kernfs_get_active(kn)) 114007c7530dSTejun Heo return -ENODEV; 114107c7530dSTejun Heo 114290c07c89STejun Heo ret = scops->rmdir(kn); 114307c7530dSTejun Heo 114407c7530dSTejun Heo kernfs_put_active(kn); 114507c7530dSTejun Heo return ret; 114680b9bbefSTejun Heo } 114780b9bbefSTejun Heo 114880b9bbefSTejun Heo static int kernfs_iop_rename(struct inode *old_dir, struct dentry *old_dentry, 11491cd66c93SMiklos Szeredi struct inode *new_dir, struct dentry *new_dentry, 11501cd66c93SMiklos Szeredi unsigned int flags) 115180b9bbefSTejun Heo { 1152319ba91dSShaohua Li struct kernfs_node *kn = kernfs_dentry_node(old_dentry); 115380b9bbefSTejun Heo struct kernfs_node *new_parent = new_dir->i_private; 115490c07c89STejun Heo struct kernfs_syscall_ops *scops = kernfs_root(kn)->syscall_ops; 115507c7530dSTejun Heo int ret; 115680b9bbefSTejun Heo 11571cd66c93SMiklos Szeredi if (flags) 11581cd66c93SMiklos Szeredi return -EINVAL; 11591cd66c93SMiklos Szeredi 116090c07c89STejun Heo if (!scops || !scops->rename) 116180b9bbefSTejun Heo return -EPERM; 116280b9bbefSTejun Heo 116307c7530dSTejun Heo if (!kernfs_get_active(kn)) 116407c7530dSTejun Heo return -ENODEV; 116507c7530dSTejun Heo 116607c7530dSTejun Heo if (!kernfs_get_active(new_parent)) { 116707c7530dSTejun Heo kernfs_put_active(kn); 116807c7530dSTejun Heo return -ENODEV; 116907c7530dSTejun Heo } 117007c7530dSTejun Heo 117190c07c89STejun Heo ret = scops->rename(kn, new_parent, new_dentry->d_name.name); 117207c7530dSTejun Heo 117307c7530dSTejun Heo kernfs_put_active(new_parent); 117407c7530dSTejun Heo kernfs_put_active(kn); 117507c7530dSTejun Heo return ret; 117680b9bbefSTejun Heo } 117780b9bbefSTejun Heo 1178a797bfc3STejun Heo const struct inode_operations kernfs_dir_iops = { 1179c637b8acSTejun Heo .lookup = kernfs_iop_lookup, 1180c637b8acSTejun Heo .permission = kernfs_iop_permission, 1181c637b8acSTejun Heo .setattr = kernfs_iop_setattr, 1182c637b8acSTejun Heo .getattr = kernfs_iop_getattr, 1183c637b8acSTejun Heo .listxattr = kernfs_iop_listxattr, 118480b9bbefSTejun Heo 118580b9bbefSTejun Heo .mkdir = kernfs_iop_mkdir, 118680b9bbefSTejun Heo .rmdir = kernfs_iop_rmdir, 118780b9bbefSTejun Heo .rename = kernfs_iop_rename, 1188fd7b9f7bSTejun Heo }; 1189fd7b9f7bSTejun Heo 1190c637b8acSTejun Heo static struct kernfs_node *kernfs_leftmost_descendant(struct kernfs_node *pos) 1191fd7b9f7bSTejun Heo { 1192324a56e1STejun Heo struct kernfs_node *last; 1193fd7b9f7bSTejun Heo 1194fd7b9f7bSTejun Heo while (true) { 1195fd7b9f7bSTejun Heo struct rb_node *rbn; 1196fd7b9f7bSTejun Heo 1197fd7b9f7bSTejun Heo last = pos; 1198fd7b9f7bSTejun Heo 1199df23fc39STejun Heo if (kernfs_type(pos) != KERNFS_DIR) 1200fd7b9f7bSTejun Heo break; 1201fd7b9f7bSTejun Heo 1202adc5e8b5STejun Heo rbn = rb_first(&pos->dir.children); 1203fd7b9f7bSTejun Heo if (!rbn) 1204fd7b9f7bSTejun Heo break; 1205fd7b9f7bSTejun Heo 1206324a56e1STejun Heo pos = rb_to_kn(rbn); 1207fd7b9f7bSTejun Heo } 1208fd7b9f7bSTejun Heo 1209fd7b9f7bSTejun Heo return last; 1210fd7b9f7bSTejun Heo } 1211fd7b9f7bSTejun Heo 1212fd7b9f7bSTejun Heo /** 1213c637b8acSTejun Heo * kernfs_next_descendant_post - find the next descendant for post-order walk 1214fd7b9f7bSTejun Heo * @pos: the current position (%NULL to initiate traversal) 1215324a56e1STejun Heo * @root: kernfs_node whose descendants to walk 1216fd7b9f7bSTejun Heo * 1217fd7b9f7bSTejun Heo * Find the next descendant to visit for post-order traversal of @root's 1218fd7b9f7bSTejun Heo * descendants. @root is included in the iteration and the last node to be 1219fd7b9f7bSTejun Heo * visited. 1220fd7b9f7bSTejun Heo */ 1221c637b8acSTejun Heo static struct kernfs_node *kernfs_next_descendant_post(struct kernfs_node *pos, 1222324a56e1STejun Heo struct kernfs_node *root) 1223fd7b9f7bSTejun Heo { 1224fd7b9f7bSTejun Heo struct rb_node *rbn; 1225fd7b9f7bSTejun Heo 1226a797bfc3STejun Heo lockdep_assert_held(&kernfs_mutex); 1227fd7b9f7bSTejun Heo 1228fd7b9f7bSTejun Heo /* if first iteration, visit leftmost descendant which may be root */ 1229fd7b9f7bSTejun Heo if (!pos) 1230c637b8acSTejun Heo return kernfs_leftmost_descendant(root); 1231fd7b9f7bSTejun Heo 1232fd7b9f7bSTejun Heo /* if we visited @root, we're done */ 1233fd7b9f7bSTejun Heo if (pos == root) 1234fd7b9f7bSTejun Heo return NULL; 1235fd7b9f7bSTejun Heo 1236fd7b9f7bSTejun Heo /* if there's an unvisited sibling, visit its leftmost descendant */ 1237adc5e8b5STejun Heo rbn = rb_next(&pos->rb); 1238fd7b9f7bSTejun Heo if (rbn) 1239c637b8acSTejun Heo return kernfs_leftmost_descendant(rb_to_kn(rbn)); 1240fd7b9f7bSTejun Heo 1241fd7b9f7bSTejun Heo /* no sibling left, visit parent */ 1242adc5e8b5STejun Heo return pos->parent; 1243fd7b9f7bSTejun Heo } 1244fd7b9f7bSTejun Heo 1245d35258efSTejun Heo /** 1246d35258efSTejun Heo * kernfs_activate - activate a node which started deactivated 1247d35258efSTejun Heo * @kn: kernfs_node whose subtree is to be activated 1248d35258efSTejun Heo * 1249d35258efSTejun Heo * If the root has KERNFS_ROOT_CREATE_DEACTIVATED set, a newly created node 1250d35258efSTejun Heo * needs to be explicitly activated. A node which hasn't been activated 1251d35258efSTejun Heo * isn't visible to userland and deactivation is skipped during its 1252d35258efSTejun Heo * removal. This is useful to construct atomic init sequences where 1253d35258efSTejun Heo * creation of multiple nodes should either succeed or fail atomically. 1254d35258efSTejun Heo * 1255d35258efSTejun Heo * The caller is responsible for ensuring that this function is not called 1256d35258efSTejun Heo * after kernfs_remove*() is invoked on @kn. 1257d35258efSTejun Heo */ 1258d35258efSTejun Heo void kernfs_activate(struct kernfs_node *kn) 1259d35258efSTejun Heo { 1260d35258efSTejun Heo struct kernfs_node *pos; 1261d35258efSTejun Heo 1262d35258efSTejun Heo mutex_lock(&kernfs_mutex); 1263d35258efSTejun Heo 1264d35258efSTejun Heo pos = NULL; 1265d35258efSTejun Heo while ((pos = kernfs_next_descendant_post(pos, kn))) { 1266d35258efSTejun Heo if (!pos || (pos->flags & KERNFS_ACTIVATED)) 1267d35258efSTejun Heo continue; 1268d35258efSTejun Heo 1269d35258efSTejun Heo WARN_ON_ONCE(pos->parent && RB_EMPTY_NODE(&pos->rb)); 1270d35258efSTejun Heo WARN_ON_ONCE(atomic_read(&pos->active) != KN_DEACTIVATED_BIAS); 1271d35258efSTejun Heo 1272d35258efSTejun Heo atomic_sub(KN_DEACTIVATED_BIAS, &pos->active); 1273d35258efSTejun Heo pos->flags |= KERNFS_ACTIVATED; 1274d35258efSTejun Heo } 1275d35258efSTejun Heo 1276d35258efSTejun Heo mutex_unlock(&kernfs_mutex); 1277d35258efSTejun Heo } 1278d35258efSTejun Heo 1279988cd7afSTejun Heo static void __kernfs_remove(struct kernfs_node *kn) 1280fd7b9f7bSTejun Heo { 128135beab06STejun Heo struct kernfs_node *pos; 128235beab06STejun Heo 128335beab06STejun Heo lockdep_assert_held(&kernfs_mutex); 1284fd7b9f7bSTejun Heo 12856b0afc2aSTejun Heo /* 12866b0afc2aSTejun Heo * Short-circuit if non-root @kn has already finished removal. 12876b0afc2aSTejun Heo * This is for kernfs_remove_self() which plays with active ref 12886b0afc2aSTejun Heo * after removal. 12896b0afc2aSTejun Heo */ 12906b0afc2aSTejun Heo if (!kn || (kn->parent && RB_EMPTY_NODE(&kn->rb))) 1291ce9b499cSGreg Kroah-Hartman return; 1292ce9b499cSGreg Kroah-Hartman 1293c637b8acSTejun Heo pr_debug("kernfs %s: removing\n", kn->name); 1294fd7b9f7bSTejun Heo 129581c173cbSTejun Heo /* prevent any new usage under @kn by deactivating all nodes */ 129635beab06STejun Heo pos = NULL; 129735beab06STejun Heo while ((pos = kernfs_next_descendant_post(pos, kn))) 129881c173cbSTejun Heo if (kernfs_active(pos)) 129981c173cbSTejun Heo atomic_add(KN_DEACTIVATED_BIAS, &pos->active); 130035beab06STejun Heo 130135beab06STejun Heo /* deactivate and unlink the subtree node-by-node */ 1302fd7b9f7bSTejun Heo do { 130335beab06STejun Heo pos = kernfs_leftmost_descendant(kn); 130435beab06STejun Heo 130535beab06STejun Heo /* 130681c173cbSTejun Heo * kernfs_drain() drops kernfs_mutex temporarily and @pos's 130781c173cbSTejun Heo * base ref could have been put by someone else by the time 130881c173cbSTejun Heo * the function returns. Make sure it doesn't go away 130981c173cbSTejun Heo * underneath us. 131035beab06STejun Heo */ 131135beab06STejun Heo kernfs_get(pos); 131235beab06STejun Heo 1313d35258efSTejun Heo /* 1314d35258efSTejun Heo * Drain iff @kn was activated. This avoids draining and 1315d35258efSTejun Heo * its lockdep annotations for nodes which have never been 1316d35258efSTejun Heo * activated and allows embedding kernfs_remove() in create 1317d35258efSTejun Heo * error paths without worrying about draining. 1318d35258efSTejun Heo */ 1319d35258efSTejun Heo if (kn->flags & KERNFS_ACTIVATED) 132081c173cbSTejun Heo kernfs_drain(pos); 1321d35258efSTejun Heo else 1322d35258efSTejun Heo WARN_ON_ONCE(atomic_read(&kn->active) != KN_DEACTIVATED_BIAS); 132335beab06STejun Heo 132435beab06STejun Heo /* 132535beab06STejun Heo * kernfs_unlink_sibling() succeeds once per node. Use it 132635beab06STejun Heo * to decide who's responsible for cleanups. 132735beab06STejun Heo */ 132835beab06STejun Heo if (!pos->parent || kernfs_unlink_sibling(pos)) { 132935beab06STejun Heo struct kernfs_iattrs *ps_iattr = 133035beab06STejun Heo pos->parent ? pos->parent->iattr : NULL; 133135beab06STejun Heo 133235beab06STejun Heo /* update timestamps on the parent */ 133335beab06STejun Heo if (ps_iattr) { 133405895219SOndrej Mosnacek ktime_get_real_ts64(&ps_iattr->ia_ctime); 133505895219SOndrej Mosnacek ps_iattr->ia_mtime = ps_iattr->ia_ctime; 133635beab06STejun Heo } 133735beab06STejun Heo 1338988cd7afSTejun Heo kernfs_put(pos); 133935beab06STejun Heo } 134035beab06STejun Heo 134135beab06STejun Heo kernfs_put(pos); 134235beab06STejun Heo } while (pos != kn); 1343fd7b9f7bSTejun Heo } 1344fd7b9f7bSTejun Heo 1345fd7b9f7bSTejun Heo /** 1346324a56e1STejun Heo * kernfs_remove - remove a kernfs_node recursively 1347324a56e1STejun Heo * @kn: the kernfs_node to remove 1348fd7b9f7bSTejun Heo * 1349324a56e1STejun Heo * Remove @kn along with all its subdirectories and files. 1350fd7b9f7bSTejun Heo */ 1351324a56e1STejun Heo void kernfs_remove(struct kernfs_node *kn) 1352fd7b9f7bSTejun Heo { 1353988cd7afSTejun Heo mutex_lock(&kernfs_mutex); 1354988cd7afSTejun Heo __kernfs_remove(kn); 1355988cd7afSTejun Heo mutex_unlock(&kernfs_mutex); 1356fd7b9f7bSTejun Heo } 1357fd7b9f7bSTejun Heo 1358fd7b9f7bSTejun Heo /** 13596b0afc2aSTejun Heo * kernfs_break_active_protection - break out of active protection 13606b0afc2aSTejun Heo * @kn: the self kernfs_node 13616b0afc2aSTejun Heo * 13626b0afc2aSTejun Heo * The caller must be running off of a kernfs operation which is invoked 13636b0afc2aSTejun Heo * with an active reference - e.g. one of kernfs_ops. Each invocation of 13646b0afc2aSTejun Heo * this function must also be matched with an invocation of 13656b0afc2aSTejun Heo * kernfs_unbreak_active_protection(). 13666b0afc2aSTejun Heo * 13676b0afc2aSTejun Heo * This function releases the active reference of @kn the caller is 13686b0afc2aSTejun Heo * holding. Once this function is called, @kn may be removed at any point 13696b0afc2aSTejun Heo * and the caller is solely responsible for ensuring that the objects it 13706b0afc2aSTejun Heo * dereferences are accessible. 13716b0afc2aSTejun Heo */ 13726b0afc2aSTejun Heo void kernfs_break_active_protection(struct kernfs_node *kn) 13736b0afc2aSTejun Heo { 13746b0afc2aSTejun Heo /* 13756b0afc2aSTejun Heo * Take out ourself out of the active ref dependency chain. If 13766b0afc2aSTejun Heo * we're called without an active ref, lockdep will complain. 13776b0afc2aSTejun Heo */ 13786b0afc2aSTejun Heo kernfs_put_active(kn); 13796b0afc2aSTejun Heo } 13806b0afc2aSTejun Heo 13816b0afc2aSTejun Heo /** 13826b0afc2aSTejun Heo * kernfs_unbreak_active_protection - undo kernfs_break_active_protection() 13836b0afc2aSTejun Heo * @kn: the self kernfs_node 13846b0afc2aSTejun Heo * 13856b0afc2aSTejun Heo * If kernfs_break_active_protection() was called, this function must be 13866b0afc2aSTejun Heo * invoked before finishing the kernfs operation. Note that while this 13876b0afc2aSTejun Heo * function restores the active reference, it doesn't and can't actually 13886b0afc2aSTejun Heo * restore the active protection - @kn may already or be in the process of 13896b0afc2aSTejun Heo * being removed. Once kernfs_break_active_protection() is invoked, that 13906b0afc2aSTejun Heo * protection is irreversibly gone for the kernfs operation instance. 13916b0afc2aSTejun Heo * 13926b0afc2aSTejun Heo * While this function may be called at any point after 13936b0afc2aSTejun Heo * kernfs_break_active_protection() is invoked, its most useful location 13946b0afc2aSTejun Heo * would be right before the enclosing kernfs operation returns. 13956b0afc2aSTejun Heo */ 13966b0afc2aSTejun Heo void kernfs_unbreak_active_protection(struct kernfs_node *kn) 13976b0afc2aSTejun Heo { 13986b0afc2aSTejun Heo /* 13996b0afc2aSTejun Heo * @kn->active could be in any state; however, the increment we do 14006b0afc2aSTejun Heo * here will be undone as soon as the enclosing kernfs operation 14016b0afc2aSTejun Heo * finishes and this temporary bump can't break anything. If @kn 14026b0afc2aSTejun Heo * is alive, nothing changes. If @kn is being deactivated, the 14036b0afc2aSTejun Heo * soon-to-follow put will either finish deactivation or restore 14046b0afc2aSTejun Heo * deactivated state. If @kn is already removed, the temporary 14056b0afc2aSTejun Heo * bump is guaranteed to be gone before @kn is released. 14066b0afc2aSTejun Heo */ 14076b0afc2aSTejun Heo atomic_inc(&kn->active); 14086b0afc2aSTejun Heo if (kernfs_lockdep(kn)) 14096b0afc2aSTejun Heo rwsem_acquire(&kn->dep_map, 0, 1, _RET_IP_); 14106b0afc2aSTejun Heo } 14116b0afc2aSTejun Heo 14126b0afc2aSTejun Heo /** 14136b0afc2aSTejun Heo * kernfs_remove_self - remove a kernfs_node from its own method 14146b0afc2aSTejun Heo * @kn: the self kernfs_node to remove 14156b0afc2aSTejun Heo * 14166b0afc2aSTejun Heo * The caller must be running off of a kernfs operation which is invoked 14176b0afc2aSTejun Heo * with an active reference - e.g. one of kernfs_ops. This can be used to 14186b0afc2aSTejun Heo * implement a file operation which deletes itself. 14196b0afc2aSTejun Heo * 14206b0afc2aSTejun Heo * For example, the "delete" file for a sysfs device directory can be 14216b0afc2aSTejun Heo * implemented by invoking kernfs_remove_self() on the "delete" file 14226b0afc2aSTejun Heo * itself. This function breaks the circular dependency of trying to 14236b0afc2aSTejun Heo * deactivate self while holding an active ref itself. It isn't necessary 14246b0afc2aSTejun Heo * to modify the usual removal path to use kernfs_remove_self(). The 14256b0afc2aSTejun Heo * "delete" implementation can simply invoke kernfs_remove_self() on self 14266b0afc2aSTejun Heo * before proceeding with the usual removal path. kernfs will ignore later 14276b0afc2aSTejun Heo * kernfs_remove() on self. 14286b0afc2aSTejun Heo * 14296b0afc2aSTejun Heo * kernfs_remove_self() can be called multiple times concurrently on the 14306b0afc2aSTejun Heo * same kernfs_node. Only the first one actually performs removal and 14316b0afc2aSTejun Heo * returns %true. All others will wait until the kernfs operation which 14326b0afc2aSTejun Heo * won self-removal finishes and return %false. Note that the losers wait 14336b0afc2aSTejun Heo * for the completion of not only the winning kernfs_remove_self() but also 14346b0afc2aSTejun Heo * the whole kernfs_ops which won the arbitration. This can be used to 14356b0afc2aSTejun Heo * guarantee, for example, all concurrent writes to a "delete" file to 14366b0afc2aSTejun Heo * finish only after the whole operation is complete. 14376b0afc2aSTejun Heo */ 14386b0afc2aSTejun Heo bool kernfs_remove_self(struct kernfs_node *kn) 14396b0afc2aSTejun Heo { 14406b0afc2aSTejun Heo bool ret; 14416b0afc2aSTejun Heo 14426b0afc2aSTejun Heo mutex_lock(&kernfs_mutex); 14436b0afc2aSTejun Heo kernfs_break_active_protection(kn); 14446b0afc2aSTejun Heo 14456b0afc2aSTejun Heo /* 14466b0afc2aSTejun Heo * SUICIDAL is used to arbitrate among competing invocations. Only 14476b0afc2aSTejun Heo * the first one will actually perform removal. When the removal 14486b0afc2aSTejun Heo * is complete, SUICIDED is set and the active ref is restored 14496b0afc2aSTejun Heo * while holding kernfs_mutex. The ones which lost arbitration 14506b0afc2aSTejun Heo * waits for SUICDED && drained which can happen only after the 14516b0afc2aSTejun Heo * enclosing kernfs operation which executed the winning instance 14526b0afc2aSTejun Heo * of kernfs_remove_self() finished. 14536b0afc2aSTejun Heo */ 14546b0afc2aSTejun Heo if (!(kn->flags & KERNFS_SUICIDAL)) { 14556b0afc2aSTejun Heo kn->flags |= KERNFS_SUICIDAL; 14566b0afc2aSTejun Heo __kernfs_remove(kn); 14576b0afc2aSTejun Heo kn->flags |= KERNFS_SUICIDED; 14586b0afc2aSTejun Heo ret = true; 14596b0afc2aSTejun Heo } else { 14606b0afc2aSTejun Heo wait_queue_head_t *waitq = &kernfs_root(kn)->deactivate_waitq; 14616b0afc2aSTejun Heo DEFINE_WAIT(wait); 14626b0afc2aSTejun Heo 14636b0afc2aSTejun Heo while (true) { 14646b0afc2aSTejun Heo prepare_to_wait(waitq, &wait, TASK_UNINTERRUPTIBLE); 14656b0afc2aSTejun Heo 14666b0afc2aSTejun Heo if ((kn->flags & KERNFS_SUICIDED) && 14676b0afc2aSTejun Heo atomic_read(&kn->active) == KN_DEACTIVATED_BIAS) 14686b0afc2aSTejun Heo break; 14696b0afc2aSTejun Heo 14706b0afc2aSTejun Heo mutex_unlock(&kernfs_mutex); 14716b0afc2aSTejun Heo schedule(); 14726b0afc2aSTejun Heo mutex_lock(&kernfs_mutex); 14736b0afc2aSTejun Heo } 14746b0afc2aSTejun Heo finish_wait(waitq, &wait); 14756b0afc2aSTejun Heo WARN_ON_ONCE(!RB_EMPTY_NODE(&kn->rb)); 14766b0afc2aSTejun Heo ret = false; 14776b0afc2aSTejun Heo } 14786b0afc2aSTejun Heo 14796b0afc2aSTejun Heo /* 14806b0afc2aSTejun Heo * This must be done while holding kernfs_mutex; otherwise, waiting 14816b0afc2aSTejun Heo * for SUICIDED && deactivated could finish prematurely. 14826b0afc2aSTejun Heo */ 14836b0afc2aSTejun Heo kernfs_unbreak_active_protection(kn); 14846b0afc2aSTejun Heo 14856b0afc2aSTejun Heo mutex_unlock(&kernfs_mutex); 14866b0afc2aSTejun Heo return ret; 14876b0afc2aSTejun Heo } 14886b0afc2aSTejun Heo 14896b0afc2aSTejun Heo /** 1490324a56e1STejun Heo * kernfs_remove_by_name_ns - find a kernfs_node by name and remove it 1491324a56e1STejun Heo * @parent: parent of the target 1492324a56e1STejun Heo * @name: name of the kernfs_node to remove 1493324a56e1STejun Heo * @ns: namespace tag of the kernfs_node to remove 1494fd7b9f7bSTejun Heo * 1495324a56e1STejun Heo * Look for the kernfs_node with @name and @ns under @parent and remove it. 1496324a56e1STejun Heo * Returns 0 on success, -ENOENT if such entry doesn't exist. 1497fd7b9f7bSTejun Heo */ 1498324a56e1STejun Heo int kernfs_remove_by_name_ns(struct kernfs_node *parent, const char *name, 1499fd7b9f7bSTejun Heo const void *ns) 1500fd7b9f7bSTejun Heo { 1501324a56e1STejun Heo struct kernfs_node *kn; 1502fd7b9f7bSTejun Heo 1503324a56e1STejun Heo if (!parent) { 1504c637b8acSTejun Heo WARN(1, KERN_WARNING "kernfs: can not remove '%s', no directory\n", 1505fd7b9f7bSTejun Heo name); 1506fd7b9f7bSTejun Heo return -ENOENT; 1507fd7b9f7bSTejun Heo } 1508fd7b9f7bSTejun Heo 1509988cd7afSTejun Heo mutex_lock(&kernfs_mutex); 1510fd7b9f7bSTejun Heo 1511324a56e1STejun Heo kn = kernfs_find_ns(parent, name, ns); 1512324a56e1STejun Heo if (kn) 1513988cd7afSTejun Heo __kernfs_remove(kn); 1514fd7b9f7bSTejun Heo 1515988cd7afSTejun Heo mutex_unlock(&kernfs_mutex); 1516fd7b9f7bSTejun Heo 1517324a56e1STejun Heo if (kn) 1518fd7b9f7bSTejun Heo return 0; 1519fd7b9f7bSTejun Heo else 1520fd7b9f7bSTejun Heo return -ENOENT; 1521fd7b9f7bSTejun Heo } 1522fd7b9f7bSTejun Heo 1523fd7b9f7bSTejun Heo /** 1524fd7b9f7bSTejun Heo * kernfs_rename_ns - move and rename a kernfs_node 1525324a56e1STejun Heo * @kn: target node 1526fd7b9f7bSTejun Heo * @new_parent: new parent to put @sd under 1527fd7b9f7bSTejun Heo * @new_name: new name 1528fd7b9f7bSTejun Heo * @new_ns: new namespace tag 1529fd7b9f7bSTejun Heo */ 1530324a56e1STejun Heo int kernfs_rename_ns(struct kernfs_node *kn, struct kernfs_node *new_parent, 1531fd7b9f7bSTejun Heo const char *new_name, const void *new_ns) 1532fd7b9f7bSTejun Heo { 15333eef34adSTejun Heo struct kernfs_node *old_parent; 15343eef34adSTejun Heo const char *old_name = NULL; 1535fd7b9f7bSTejun Heo int error; 1536fd7b9f7bSTejun Heo 15373eef34adSTejun Heo /* can't move or rename root */ 15383eef34adSTejun Heo if (!kn->parent) 15393eef34adSTejun Heo return -EINVAL; 15403eef34adSTejun Heo 1541ae34372eSTejun Heo mutex_lock(&kernfs_mutex); 1542d0ae3d43STejun Heo 1543798c75a0SGreg Kroah-Hartman error = -ENOENT; 1544ea015218SEric W. Biederman if (!kernfs_active(kn) || !kernfs_active(new_parent) || 1545ea015218SEric W. Biederman (new_parent->flags & KERNFS_EMPTY_DIR)) 1546798c75a0SGreg Kroah-Hartman goto out; 1547798c75a0SGreg Kroah-Hartman 1548fd7b9f7bSTejun Heo error = 0; 1549adc5e8b5STejun Heo if ((kn->parent == new_parent) && (kn->ns == new_ns) && 1550adc5e8b5STejun Heo (strcmp(kn->name, new_name) == 0)) 1551798c75a0SGreg Kroah-Hartman goto out; /* nothing to rename */ 1552fd7b9f7bSTejun Heo 1553fd7b9f7bSTejun Heo error = -EEXIST; 1554fd7b9f7bSTejun Heo if (kernfs_find_ns(new_parent, new_name, new_ns)) 1555798c75a0SGreg Kroah-Hartman goto out; 1556fd7b9f7bSTejun Heo 1557324a56e1STejun Heo /* rename kernfs_node */ 1558adc5e8b5STejun Heo if (strcmp(kn->name, new_name) != 0) { 1559fd7b9f7bSTejun Heo error = -ENOMEM; 156075287a67SAndrzej Hajda new_name = kstrdup_const(new_name, GFP_KERNEL); 1561fd7b9f7bSTejun Heo if (!new_name) 1562798c75a0SGreg Kroah-Hartman goto out; 15633eef34adSTejun Heo } else { 15643eef34adSTejun Heo new_name = NULL; 1565fd7b9f7bSTejun Heo } 1566fd7b9f7bSTejun Heo 1567fd7b9f7bSTejun Heo /* 1568fd7b9f7bSTejun Heo * Move to the appropriate place in the appropriate directories rbtree. 1569fd7b9f7bSTejun Heo */ 1570c637b8acSTejun Heo kernfs_unlink_sibling(kn); 1571fd7b9f7bSTejun Heo kernfs_get(new_parent); 15723eef34adSTejun Heo 15733eef34adSTejun Heo /* rename_lock protects ->parent and ->name accessors */ 15743eef34adSTejun Heo spin_lock_irq(&kernfs_rename_lock); 15753eef34adSTejun Heo 15763eef34adSTejun Heo old_parent = kn->parent; 1577adc5e8b5STejun Heo kn->parent = new_parent; 15783eef34adSTejun Heo 15793eef34adSTejun Heo kn->ns = new_ns; 15803eef34adSTejun Heo if (new_name) { 15813eef34adSTejun Heo old_name = kn->name; 15823eef34adSTejun Heo kn->name = new_name; 15833eef34adSTejun Heo } 15843eef34adSTejun Heo 15853eef34adSTejun Heo spin_unlock_irq(&kernfs_rename_lock); 15863eef34adSTejun Heo 15879561a896STejun Heo kn->hash = kernfs_name_hash(kn->name, kn->ns); 1588c637b8acSTejun Heo kernfs_link_sibling(kn); 1589fd7b9f7bSTejun Heo 15903eef34adSTejun Heo kernfs_put(old_parent); 159175287a67SAndrzej Hajda kfree_const(old_name); 15923eef34adSTejun Heo 1593fd7b9f7bSTejun Heo error = 0; 1594ae34372eSTejun Heo out: 1595798c75a0SGreg Kroah-Hartman mutex_unlock(&kernfs_mutex); 1596fd7b9f7bSTejun Heo return error; 1597fd7b9f7bSTejun Heo } 1598fd7b9f7bSTejun Heo 1599fd7b9f7bSTejun Heo /* Relationship between s_mode and the DT_xxx types */ 1600324a56e1STejun Heo static inline unsigned char dt_type(struct kernfs_node *kn) 1601fd7b9f7bSTejun Heo { 1602adc5e8b5STejun Heo return (kn->mode >> 12) & 15; 1603fd7b9f7bSTejun Heo } 1604fd7b9f7bSTejun Heo 1605c637b8acSTejun Heo static int kernfs_dir_fop_release(struct inode *inode, struct file *filp) 1606fd7b9f7bSTejun Heo { 1607fd7b9f7bSTejun Heo kernfs_put(filp->private_data); 1608fd7b9f7bSTejun Heo return 0; 1609fd7b9f7bSTejun Heo } 1610fd7b9f7bSTejun Heo 1611c637b8acSTejun Heo static struct kernfs_node *kernfs_dir_pos(const void *ns, 1612324a56e1STejun Heo struct kernfs_node *parent, loff_t hash, struct kernfs_node *pos) 1613fd7b9f7bSTejun Heo { 1614fd7b9f7bSTejun Heo if (pos) { 161581c173cbSTejun Heo int valid = kernfs_active(pos) && 1616798c75a0SGreg Kroah-Hartman pos->parent == parent && hash == pos->hash; 1617fd7b9f7bSTejun Heo kernfs_put(pos); 1618fd7b9f7bSTejun Heo if (!valid) 1619fd7b9f7bSTejun Heo pos = NULL; 1620fd7b9f7bSTejun Heo } 1621fd7b9f7bSTejun Heo if (!pos && (hash > 1) && (hash < INT_MAX)) { 1622adc5e8b5STejun Heo struct rb_node *node = parent->dir.children.rb_node; 1623fd7b9f7bSTejun Heo while (node) { 1624324a56e1STejun Heo pos = rb_to_kn(node); 1625fd7b9f7bSTejun Heo 1626adc5e8b5STejun Heo if (hash < pos->hash) 1627fd7b9f7bSTejun Heo node = node->rb_left; 1628adc5e8b5STejun Heo else if (hash > pos->hash) 1629fd7b9f7bSTejun Heo node = node->rb_right; 1630fd7b9f7bSTejun Heo else 1631fd7b9f7bSTejun Heo break; 1632fd7b9f7bSTejun Heo } 1633fd7b9f7bSTejun Heo } 1634b9c9dad0STejun Heo /* Skip over entries which are dying/dead or in the wrong namespace */ 1635b9c9dad0STejun Heo while (pos && (!kernfs_active(pos) || pos->ns != ns)) { 1636adc5e8b5STejun Heo struct rb_node *node = rb_next(&pos->rb); 1637fd7b9f7bSTejun Heo if (!node) 1638fd7b9f7bSTejun Heo pos = NULL; 1639fd7b9f7bSTejun Heo else 1640324a56e1STejun Heo pos = rb_to_kn(node); 1641fd7b9f7bSTejun Heo } 1642fd7b9f7bSTejun Heo return pos; 1643fd7b9f7bSTejun Heo } 1644fd7b9f7bSTejun Heo 1645c637b8acSTejun Heo static struct kernfs_node *kernfs_dir_next_pos(const void *ns, 1646324a56e1STejun Heo struct kernfs_node *parent, ino_t ino, struct kernfs_node *pos) 1647fd7b9f7bSTejun Heo { 1648c637b8acSTejun Heo pos = kernfs_dir_pos(ns, parent, ino, pos); 1649b9c9dad0STejun Heo if (pos) { 1650fd7b9f7bSTejun Heo do { 1651adc5e8b5STejun Heo struct rb_node *node = rb_next(&pos->rb); 1652fd7b9f7bSTejun Heo if (!node) 1653fd7b9f7bSTejun Heo pos = NULL; 1654fd7b9f7bSTejun Heo else 1655324a56e1STejun Heo pos = rb_to_kn(node); 1656b9c9dad0STejun Heo } while (pos && (!kernfs_active(pos) || pos->ns != ns)); 1657b9c9dad0STejun Heo } 1658fd7b9f7bSTejun Heo return pos; 1659fd7b9f7bSTejun Heo } 1660fd7b9f7bSTejun Heo 1661c637b8acSTejun Heo static int kernfs_fop_readdir(struct file *file, struct dir_context *ctx) 1662fd7b9f7bSTejun Heo { 1663fd7b9f7bSTejun Heo struct dentry *dentry = file->f_path.dentry; 1664319ba91dSShaohua Li struct kernfs_node *parent = kernfs_dentry_node(dentry); 1665324a56e1STejun Heo struct kernfs_node *pos = file->private_data; 1666fd7b9f7bSTejun Heo const void *ns = NULL; 1667fd7b9f7bSTejun Heo 1668fd7b9f7bSTejun Heo if (!dir_emit_dots(file, ctx)) 1669fd7b9f7bSTejun Heo return 0; 1670a797bfc3STejun Heo mutex_lock(&kernfs_mutex); 1671fd7b9f7bSTejun Heo 1672324a56e1STejun Heo if (kernfs_ns_enabled(parent)) 1673c525aaddSTejun Heo ns = kernfs_info(dentry->d_sb)->ns; 1674fd7b9f7bSTejun Heo 1675c637b8acSTejun Heo for (pos = kernfs_dir_pos(ns, parent, ctx->pos, pos); 1676fd7b9f7bSTejun Heo pos; 1677c637b8acSTejun Heo pos = kernfs_dir_next_pos(ns, parent, ctx->pos, pos)) { 1678adc5e8b5STejun Heo const char *name = pos->name; 1679fd7b9f7bSTejun Heo unsigned int type = dt_type(pos); 1680fd7b9f7bSTejun Heo int len = strlen(name); 1681c53cd490SShaohua Li ino_t ino = pos->id.ino; 1682fd7b9f7bSTejun Heo 1683adc5e8b5STejun Heo ctx->pos = pos->hash; 1684fd7b9f7bSTejun Heo file->private_data = pos; 1685fd7b9f7bSTejun Heo kernfs_get(pos); 1686fd7b9f7bSTejun Heo 1687a797bfc3STejun Heo mutex_unlock(&kernfs_mutex); 1688fd7b9f7bSTejun Heo if (!dir_emit(ctx, name, len, ino, type)) 1689fd7b9f7bSTejun Heo return 0; 1690a797bfc3STejun Heo mutex_lock(&kernfs_mutex); 1691fd7b9f7bSTejun Heo } 1692a797bfc3STejun Heo mutex_unlock(&kernfs_mutex); 1693fd7b9f7bSTejun Heo file->private_data = NULL; 1694fd7b9f7bSTejun Heo ctx->pos = INT_MAX; 1695fd7b9f7bSTejun Heo return 0; 1696fd7b9f7bSTejun Heo } 1697fd7b9f7bSTejun Heo 1698a797bfc3STejun Heo const struct file_operations kernfs_dir_fops = { 1699fd7b9f7bSTejun Heo .read = generic_read_dir, 17008cb0d2c1SAl Viro .iterate_shared = kernfs_fop_readdir, 1701c637b8acSTejun Heo .release = kernfs_dir_fop_release, 17028cb0d2c1SAl Viro .llseek = generic_file_llseek, 1703fd7b9f7bSTejun Heo }; 1704