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)) 441324a56e1STejun Heo rwsem_release(&kn->dep_map, 1, _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_); 479324a56e1STejun Heo rwsem_release(&kn->dep_map, 1, _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 511adc5e8b5STejun Heo if (!kn || !atomic_dec_and_test(&kn->count)) 512fd7b9f7bSTejun Heo return; 513324a56e1STejun Heo root = kernfs_root(kn); 514fd7b9f7bSTejun Heo repeat: 51581c173cbSTejun Heo /* 51681c173cbSTejun Heo * Moving/renaming is always done while holding reference. 517adc5e8b5STejun Heo * kn->parent won't change beneath us. 518fd7b9f7bSTejun Heo */ 519adc5e8b5STejun Heo parent = kn->parent; 520fd7b9f7bSTejun Heo 52181c173cbSTejun Heo WARN_ONCE(atomic_read(&kn->active) != KN_DEACTIVATED_BIAS, 52281c173cbSTejun Heo "kernfs_put: %s/%s: released with incorrect active_ref %d\n", 52381c173cbSTejun Heo parent ? parent->name : "", kn->name, atomic_read(&kn->active)); 524fd7b9f7bSTejun Heo 525df23fc39STejun Heo if (kernfs_type(kn) == KERNFS_LINK) 526adc5e8b5STejun Heo kernfs_put(kn->symlink.target_kn); 527dfeb0750STejun Heo 52875287a67SAndrzej Hajda kfree_const(kn->name); 529dfeb0750STejun Heo 530adc5e8b5STejun Heo if (kn->iattr) { 531adc5e8b5STejun Heo simple_xattrs_free(&kn->iattr->xattrs); 53226e28d68SAyush Mittal kmem_cache_free(kernfs_iattrs_cache, kn->iattr); 5332322392bSTejun Heo } 5347d35079fSShaohua Li spin_lock(&kernfs_idr_lock); 53567c0496eSTejun Heo idr_remove(&root->ino_idr, kernfs_ino(kn)); 5367d35079fSShaohua Li spin_unlock(&kernfs_idr_lock); 537a797bfc3STejun Heo kmem_cache_free(kernfs_node_cache, kn); 538fd7b9f7bSTejun Heo 539324a56e1STejun Heo kn = parent; 540324a56e1STejun Heo if (kn) { 541adc5e8b5STejun Heo if (atomic_dec_and_test(&kn->count)) 542fd7b9f7bSTejun Heo goto repeat; 543ba7443bcSTejun Heo } else { 544324a56e1STejun Heo /* just released the root kn, free @root too */ 5457d35079fSShaohua Li idr_destroy(&root->ino_idr); 546ba7443bcSTejun Heo kfree(root); 547ba7443bcSTejun Heo } 548fd7b9f7bSTejun Heo } 549fd7b9f7bSTejun Heo EXPORT_SYMBOL_GPL(kernfs_put); 550fd7b9f7bSTejun Heo 551c637b8acSTejun Heo static int kernfs_dop_revalidate(struct dentry *dentry, unsigned int flags) 552fd7b9f7bSTejun Heo { 553324a56e1STejun Heo struct kernfs_node *kn; 554fd7b9f7bSTejun Heo 555fd7b9f7bSTejun Heo if (flags & LOOKUP_RCU) 556fd7b9f7bSTejun Heo return -ECHILD; 557fd7b9f7bSTejun Heo 55819bbb926STejun Heo /* Always perform fresh lookup for negatives */ 5592b0143b5SDavid Howells if (d_really_is_negative(dentry)) 56019bbb926STejun Heo goto out_bad_unlocked; 56119bbb926STejun Heo 562319ba91dSShaohua Li kn = kernfs_dentry_node(dentry); 563a797bfc3STejun Heo mutex_lock(&kernfs_mutex); 564fd7b9f7bSTejun Heo 56581c173cbSTejun Heo /* The kernfs node has been deactivated */ 56681c173cbSTejun Heo if (!kernfs_active(kn)) 567fd7b9f7bSTejun Heo goto out_bad; 568fd7b9f7bSTejun Heo 569c637b8acSTejun Heo /* The kernfs node has been moved? */ 570319ba91dSShaohua Li if (kernfs_dentry_node(dentry->d_parent) != kn->parent) 571fd7b9f7bSTejun Heo goto out_bad; 572fd7b9f7bSTejun Heo 573c637b8acSTejun Heo /* The kernfs node has been renamed */ 574adc5e8b5STejun Heo if (strcmp(dentry->d_name.name, kn->name) != 0) 575fd7b9f7bSTejun Heo goto out_bad; 576fd7b9f7bSTejun Heo 577c637b8acSTejun Heo /* The kernfs node has been moved to a different namespace */ 578adc5e8b5STejun Heo if (kn->parent && kernfs_ns_enabled(kn->parent) && 579c525aaddSTejun Heo kernfs_info(dentry->d_sb)->ns != kn->ns) 580fd7b9f7bSTejun Heo goto out_bad; 581fd7b9f7bSTejun Heo 582a797bfc3STejun Heo mutex_unlock(&kernfs_mutex); 583fd7b9f7bSTejun Heo return 1; 584fd7b9f7bSTejun Heo out_bad: 585a797bfc3STejun Heo mutex_unlock(&kernfs_mutex); 58619bbb926STejun Heo out_bad_unlocked: 587fd7b9f7bSTejun Heo return 0; 588fd7b9f7bSTejun Heo } 589fd7b9f7bSTejun Heo 590a797bfc3STejun Heo const struct dentry_operations kernfs_dops = { 591c637b8acSTejun Heo .d_revalidate = kernfs_dop_revalidate, 592fd7b9f7bSTejun Heo }; 593fd7b9f7bSTejun Heo 5940c23b225STejun Heo /** 5950c23b225STejun Heo * kernfs_node_from_dentry - determine kernfs_node associated with a dentry 5960c23b225STejun Heo * @dentry: the dentry in question 5970c23b225STejun Heo * 5980c23b225STejun Heo * Return the kernfs_node associated with @dentry. If @dentry is not a 5990c23b225STejun Heo * kernfs one, %NULL is returned. 6000c23b225STejun Heo * 6010c23b225STejun Heo * While the returned kernfs_node will stay accessible as long as @dentry 6020c23b225STejun Heo * is accessible, the returned node can be in any state and the caller is 6030c23b225STejun Heo * fully responsible for determining what's accessible. 6040c23b225STejun Heo */ 6050c23b225STejun Heo struct kernfs_node *kernfs_node_from_dentry(struct dentry *dentry) 6060c23b225STejun Heo { 607319ba91dSShaohua Li if (dentry->d_sb->s_op == &kernfs_sops && 608319ba91dSShaohua Li !d_really_is_negative(dentry)) 609319ba91dSShaohua Li return kernfs_dentry_node(dentry); 6100c23b225STejun Heo return NULL; 6110c23b225STejun Heo } 6120c23b225STejun Heo 613db4aad20STejun Heo static struct kernfs_node *__kernfs_new_node(struct kernfs_root *root, 614e19dfdc8SOndrej Mosnacek struct kernfs_node *parent, 615db4aad20STejun Heo const char *name, umode_t mode, 616488dee96SDmitry Torokhov kuid_t uid, kgid_t gid, 617db4aad20STejun Heo unsigned flags) 618fd7b9f7bSTejun Heo { 619324a56e1STejun Heo struct kernfs_node *kn; 6204a3ef68aSShaohua Li u32 gen; 621bc755553STejun Heo int ret; 622fd7b9f7bSTejun Heo 623dfeb0750STejun Heo name = kstrdup_const(name, GFP_KERNEL); 624fd7b9f7bSTejun Heo if (!name) 625fd7b9f7bSTejun Heo return NULL; 626fd7b9f7bSTejun Heo 627a797bfc3STejun Heo kn = kmem_cache_zalloc(kernfs_node_cache, GFP_KERNEL); 628324a56e1STejun Heo if (!kn) 629fd7b9f7bSTejun Heo goto err_out1; 630fd7b9f7bSTejun Heo 6317d35079fSShaohua Li idr_preload(GFP_KERNEL); 6327d35079fSShaohua Li spin_lock(&kernfs_idr_lock); 6334a3ef68aSShaohua Li ret = idr_alloc_cyclic(&root->ino_idr, kn, 1, 0, GFP_ATOMIC); 634e23f568aSTejun Heo if (ret >= 0 && ret < root->last_ino) 6354a3ef68aSShaohua Li root->next_generation++; 6364a3ef68aSShaohua Li gen = root->next_generation; 637e23f568aSTejun Heo root->last_ino = ret; 6387d35079fSShaohua Li spin_unlock(&kernfs_idr_lock); 6397d35079fSShaohua Li idr_preload_end(); 640bc755553STejun Heo if (ret < 0) 641fd7b9f7bSTejun Heo goto err_out2; 64267c0496eSTejun Heo 64367c0496eSTejun Heo kn->id = (u64)gen << 32 | ret; 644fd7b9f7bSTejun Heo 645b680b081STejun Heo atomic_set(&kn->count, 1); 64681c173cbSTejun Heo atomic_set(&kn->active, KN_DEACTIVATED_BIAS); 64735beab06STejun Heo RB_CLEAR_NODE(&kn->rb); 648fd7b9f7bSTejun Heo 649adc5e8b5STejun Heo kn->name = name; 650adc5e8b5STejun Heo kn->mode = mode; 65181c173cbSTejun Heo kn->flags = flags; 652fd7b9f7bSTejun Heo 653488dee96SDmitry Torokhov if (!uid_eq(uid, GLOBAL_ROOT_UID) || !gid_eq(gid, GLOBAL_ROOT_GID)) { 654488dee96SDmitry Torokhov struct iattr iattr = { 655488dee96SDmitry Torokhov .ia_valid = ATTR_UID | ATTR_GID, 656488dee96SDmitry Torokhov .ia_uid = uid, 657488dee96SDmitry Torokhov .ia_gid = gid, 658488dee96SDmitry Torokhov }; 659488dee96SDmitry Torokhov 660488dee96SDmitry Torokhov ret = __kernfs_setattr(kn, &iattr); 661488dee96SDmitry Torokhov if (ret < 0) 662488dee96SDmitry Torokhov goto err_out3; 663488dee96SDmitry Torokhov } 664488dee96SDmitry Torokhov 665e19dfdc8SOndrej Mosnacek if (parent) { 666e19dfdc8SOndrej Mosnacek ret = security_kernfs_init_security(parent, kn); 667e19dfdc8SOndrej Mosnacek if (ret) 668e19dfdc8SOndrej Mosnacek goto err_out3; 669e19dfdc8SOndrej Mosnacek } 670e19dfdc8SOndrej Mosnacek 671324a56e1STejun Heo return kn; 672fd7b9f7bSTejun Heo 673488dee96SDmitry Torokhov err_out3: 67467c0496eSTejun Heo idr_remove(&root->ino_idr, kernfs_ino(kn)); 675fd7b9f7bSTejun Heo err_out2: 676a797bfc3STejun Heo kmem_cache_free(kernfs_node_cache, kn); 677fd7b9f7bSTejun Heo err_out1: 678dfeb0750STejun Heo kfree_const(name); 679fd7b9f7bSTejun Heo return NULL; 680fd7b9f7bSTejun Heo } 681fd7b9f7bSTejun Heo 682db4aad20STejun Heo struct kernfs_node *kernfs_new_node(struct kernfs_node *parent, 683db4aad20STejun Heo const char *name, umode_t mode, 684488dee96SDmitry Torokhov kuid_t uid, kgid_t gid, 685db4aad20STejun Heo unsigned flags) 686db4aad20STejun Heo { 687db4aad20STejun Heo struct kernfs_node *kn; 688db4aad20STejun Heo 689e19dfdc8SOndrej Mosnacek kn = __kernfs_new_node(kernfs_root(parent), parent, 690488dee96SDmitry Torokhov name, mode, uid, gid, flags); 691db4aad20STejun Heo if (kn) { 692db4aad20STejun Heo kernfs_get(parent); 693db4aad20STejun Heo kn->parent = parent; 694db4aad20STejun Heo } 695db4aad20STejun Heo return kn; 696db4aad20STejun Heo } 697db4aad20STejun Heo 698ba16b284SShaohua Li /* 699fe0f726cSTejun Heo * kernfs_find_and_get_node_by_id - get kernfs_node from node id 700ba16b284SShaohua Li * @root: the kernfs root 701fe0f726cSTejun Heo * @id: the target node id 702fe0f726cSTejun Heo * 703fe0f726cSTejun Heo * @id's lower 32bits encode ino and upper gen. If the gen portion is 704fe0f726cSTejun Heo * zero, all generations are matched. 705ba16b284SShaohua Li * 706ba16b284SShaohua Li * RETURNS: 707ba16b284SShaohua Li * NULL on failure. Return a kernfs node with reference counter incremented 708ba16b284SShaohua Li */ 709fe0f726cSTejun Heo struct kernfs_node *kernfs_find_and_get_node_by_id(struct kernfs_root *root, 710fe0f726cSTejun Heo u64 id) 711ba16b284SShaohua Li { 712ba16b284SShaohua Li struct kernfs_node *kn; 713fe0f726cSTejun Heo ino_t ino = kernfs_id_ino(id); 714fe0f726cSTejun Heo u32 gen = kernfs_id_gen(id); 715ba16b284SShaohua Li 716b680b081STejun Heo spin_lock(&kernfs_idr_lock); 717b680b081STejun Heo 718ba16b284SShaohua Li kn = idr_find(&root->ino_idr, ino); 719ba16b284SShaohua Li if (!kn) 720b680b081STejun Heo goto err_unlock; 721ba16b284SShaohua Li 722fe0f726cSTejun Heo /* 0 matches all generations */ 723fe0f726cSTejun Heo if (unlikely(gen && kernfs_gen(kn) != gen)) 724fe0f726cSTejun Heo goto err_unlock; 725fe0f726cSTejun Heo 726880df131STejun Heo /* 727880df131STejun Heo * ACTIVATED is protected with kernfs_mutex but it was clear when 728880df131STejun Heo * @kn was added to idr and we just wanna see it set. No need to 729880df131STejun Heo * grab kernfs_mutex. 730880df131STejun Heo */ 731880df131STejun Heo if (unlikely(!(kn->flags & KERNFS_ACTIVATED) || 732880df131STejun Heo !atomic_inc_not_zero(&kn->count))) 733b680b081STejun Heo goto err_unlock; 734ba16b284SShaohua Li 735b680b081STejun Heo spin_unlock(&kernfs_idr_lock); 736ba16b284SShaohua Li return kn; 737b680b081STejun Heo err_unlock: 738b680b081STejun Heo spin_unlock(&kernfs_idr_lock); 739ba16b284SShaohua Li return NULL; 740ba16b284SShaohua Li } 741ba16b284SShaohua Li 742fd7b9f7bSTejun Heo /** 743c637b8acSTejun Heo * kernfs_add_one - add kernfs_node to parent without warning 744324a56e1STejun Heo * @kn: kernfs_node to be added 745fd7b9f7bSTejun Heo * 746db4aad20STejun Heo * The caller must already have initialized @kn->parent. This 747db4aad20STejun Heo * function increments nlink of the parent's inode if @kn is a 748db4aad20STejun Heo * directory and link into the children list of the parent. 749fd7b9f7bSTejun Heo * 750fd7b9f7bSTejun Heo * RETURNS: 751fd7b9f7bSTejun Heo * 0 on success, -EEXIST if entry with the given name already 752fd7b9f7bSTejun Heo * exists. 753fd7b9f7bSTejun Heo */ 754988cd7afSTejun Heo int kernfs_add_one(struct kernfs_node *kn) 755fd7b9f7bSTejun Heo { 756db4aad20STejun Heo struct kernfs_node *parent = kn->parent; 757c525aaddSTejun Heo struct kernfs_iattrs *ps_iattr; 758988cd7afSTejun Heo bool has_ns; 759fd7b9f7bSTejun Heo int ret; 760fd7b9f7bSTejun Heo 761988cd7afSTejun Heo mutex_lock(&kernfs_mutex); 762988cd7afSTejun Heo 763988cd7afSTejun Heo ret = -EINVAL; 764988cd7afSTejun Heo has_ns = kernfs_ns_enabled(parent); 765988cd7afSTejun Heo if (WARN(has_ns != (bool)kn->ns, KERN_WARNING "kernfs: ns %s in '%s' for '%s'\n", 766988cd7afSTejun Heo has_ns ? "required" : "invalid", parent->name, kn->name)) 767988cd7afSTejun Heo goto out_unlock; 768fd7b9f7bSTejun Heo 769df23fc39STejun Heo if (kernfs_type(parent) != KERNFS_DIR) 770988cd7afSTejun Heo goto out_unlock; 771fd7b9f7bSTejun Heo 772988cd7afSTejun Heo ret = -ENOENT; 773ea015218SEric W. Biederman if (parent->flags & KERNFS_EMPTY_DIR) 774ea015218SEric W. Biederman goto out_unlock; 775ea015218SEric W. Biederman 776d35258efSTejun Heo if ((parent->flags & KERNFS_ACTIVATED) && !kernfs_active(parent)) 777988cd7afSTejun Heo goto out_unlock; 778798c75a0SGreg Kroah-Hartman 779c637b8acSTejun Heo kn->hash = kernfs_name_hash(kn->name, kn->ns); 780fd7b9f7bSTejun Heo 781c637b8acSTejun Heo ret = kernfs_link_sibling(kn); 782fd7b9f7bSTejun Heo if (ret) 783988cd7afSTejun Heo goto out_unlock; 784fd7b9f7bSTejun Heo 785fd7b9f7bSTejun Heo /* Update timestamps on the parent */ 786adc5e8b5STejun Heo ps_iattr = parent->iattr; 787fd7b9f7bSTejun Heo if (ps_iattr) { 78805895219SOndrej Mosnacek ktime_get_real_ts64(&ps_iattr->ia_ctime); 78905895219SOndrej Mosnacek ps_iattr->ia_mtime = ps_iattr->ia_ctime; 790fd7b9f7bSTejun Heo } 791fd7b9f7bSTejun Heo 792d35258efSTejun Heo mutex_unlock(&kernfs_mutex); 793d35258efSTejun Heo 794d35258efSTejun Heo /* 795d35258efSTejun Heo * Activate the new node unless CREATE_DEACTIVATED is requested. 796d35258efSTejun Heo * If not activated here, the kernfs user is responsible for 797d35258efSTejun Heo * activating the node with kernfs_activate(). A node which hasn't 798d35258efSTejun Heo * been activated is not visible to userland and its removal won't 799d35258efSTejun Heo * trigger deactivation. 800d35258efSTejun Heo */ 801d35258efSTejun Heo if (!(kernfs_root(kn)->flags & KERNFS_ROOT_CREATE_DEACTIVATED)) 802d35258efSTejun Heo kernfs_activate(kn); 803d35258efSTejun Heo return 0; 804d35258efSTejun Heo 805988cd7afSTejun Heo out_unlock: 806a797bfc3STejun Heo mutex_unlock(&kernfs_mutex); 807988cd7afSTejun Heo return ret; 808fd7b9f7bSTejun Heo } 809fd7b9f7bSTejun Heo 810fd7b9f7bSTejun Heo /** 811324a56e1STejun Heo * kernfs_find_ns - find kernfs_node with the given name 812324a56e1STejun Heo * @parent: kernfs_node to search under 813fd7b9f7bSTejun Heo * @name: name to look for 814fd7b9f7bSTejun Heo * @ns: the namespace tag to use 815fd7b9f7bSTejun Heo * 816324a56e1STejun Heo * Look for kernfs_node with name @name under @parent. Returns pointer to 817324a56e1STejun Heo * the found kernfs_node on success, %NULL on failure. 818fd7b9f7bSTejun Heo */ 819324a56e1STejun Heo static struct kernfs_node *kernfs_find_ns(struct kernfs_node *parent, 820fd7b9f7bSTejun Heo const unsigned char *name, 821fd7b9f7bSTejun Heo const void *ns) 822fd7b9f7bSTejun Heo { 823adc5e8b5STejun Heo struct rb_node *node = parent->dir.children.rb_node; 824ac9bba03STejun Heo bool has_ns = kernfs_ns_enabled(parent); 825fd7b9f7bSTejun Heo unsigned int hash; 826fd7b9f7bSTejun Heo 827a797bfc3STejun Heo lockdep_assert_held(&kernfs_mutex); 828fd7b9f7bSTejun Heo 829fd7b9f7bSTejun Heo if (has_ns != (bool)ns) { 830c637b8acSTejun Heo WARN(1, KERN_WARNING "kernfs: ns %s in '%s' for '%s'\n", 831adc5e8b5STejun Heo has_ns ? "required" : "invalid", parent->name, name); 832fd7b9f7bSTejun Heo return NULL; 833fd7b9f7bSTejun Heo } 834fd7b9f7bSTejun Heo 835c637b8acSTejun Heo hash = kernfs_name_hash(name, ns); 836fd7b9f7bSTejun Heo while (node) { 837324a56e1STejun Heo struct kernfs_node *kn; 838fd7b9f7bSTejun Heo int result; 839fd7b9f7bSTejun Heo 840324a56e1STejun Heo kn = rb_to_kn(node); 841c637b8acSTejun Heo result = kernfs_name_compare(hash, name, ns, kn); 842fd7b9f7bSTejun Heo if (result < 0) 843fd7b9f7bSTejun Heo node = node->rb_left; 844fd7b9f7bSTejun Heo else if (result > 0) 845fd7b9f7bSTejun Heo node = node->rb_right; 846fd7b9f7bSTejun Heo else 847324a56e1STejun Heo return kn; 848fd7b9f7bSTejun Heo } 849fd7b9f7bSTejun Heo return NULL; 850fd7b9f7bSTejun Heo } 851fd7b9f7bSTejun Heo 852bd96f76aSTejun Heo static struct kernfs_node *kernfs_walk_ns(struct kernfs_node *parent, 853bd96f76aSTejun Heo const unsigned char *path, 854bd96f76aSTejun Heo const void *ns) 855bd96f76aSTejun Heo { 856e56ed358STejun Heo size_t len; 857e56ed358STejun Heo char *p, *name; 858bd96f76aSTejun Heo 859bd96f76aSTejun Heo lockdep_assert_held(&kernfs_mutex); 860bd96f76aSTejun Heo 861e56ed358STejun Heo /* grab kernfs_rename_lock to piggy back on kernfs_pr_cont_buf */ 862e56ed358STejun Heo spin_lock_irq(&kernfs_rename_lock); 863e56ed358STejun Heo 864e56ed358STejun Heo len = strlcpy(kernfs_pr_cont_buf, path, sizeof(kernfs_pr_cont_buf)); 865e56ed358STejun Heo 866e56ed358STejun Heo if (len >= sizeof(kernfs_pr_cont_buf)) { 867e56ed358STejun Heo spin_unlock_irq(&kernfs_rename_lock); 868bd96f76aSTejun Heo return NULL; 869e56ed358STejun Heo } 870e56ed358STejun Heo 871e56ed358STejun Heo p = kernfs_pr_cont_buf; 872bd96f76aSTejun Heo 873bd96f76aSTejun Heo while ((name = strsep(&p, "/")) && parent) { 874bd96f76aSTejun Heo if (*name == '\0') 875bd96f76aSTejun Heo continue; 876bd96f76aSTejun Heo parent = kernfs_find_ns(parent, name, ns); 877bd96f76aSTejun Heo } 878bd96f76aSTejun Heo 879e56ed358STejun Heo spin_unlock_irq(&kernfs_rename_lock); 880e56ed358STejun Heo 881bd96f76aSTejun Heo return parent; 882bd96f76aSTejun Heo } 883bd96f76aSTejun Heo 884fd7b9f7bSTejun Heo /** 885324a56e1STejun Heo * kernfs_find_and_get_ns - find and get kernfs_node with the given name 886324a56e1STejun Heo * @parent: kernfs_node to search under 887fd7b9f7bSTejun Heo * @name: name to look for 888fd7b9f7bSTejun Heo * @ns: the namespace tag to use 889fd7b9f7bSTejun Heo * 890324a56e1STejun Heo * Look for kernfs_node with name @name under @parent and get a reference 891fd7b9f7bSTejun Heo * if found. This function may sleep and returns pointer to the found 892324a56e1STejun Heo * kernfs_node on success, %NULL on failure. 893fd7b9f7bSTejun Heo */ 894324a56e1STejun Heo struct kernfs_node *kernfs_find_and_get_ns(struct kernfs_node *parent, 895fd7b9f7bSTejun Heo const char *name, const void *ns) 896fd7b9f7bSTejun Heo { 897324a56e1STejun Heo struct kernfs_node *kn; 898fd7b9f7bSTejun Heo 899a797bfc3STejun Heo mutex_lock(&kernfs_mutex); 900324a56e1STejun Heo kn = kernfs_find_ns(parent, name, ns); 901324a56e1STejun Heo kernfs_get(kn); 902a797bfc3STejun Heo mutex_unlock(&kernfs_mutex); 903fd7b9f7bSTejun Heo 904324a56e1STejun Heo return kn; 905fd7b9f7bSTejun Heo } 906fd7b9f7bSTejun Heo EXPORT_SYMBOL_GPL(kernfs_find_and_get_ns); 907fd7b9f7bSTejun Heo 908fd7b9f7bSTejun Heo /** 909bd96f76aSTejun Heo * kernfs_walk_and_get_ns - find and get kernfs_node with the given path 910bd96f76aSTejun Heo * @parent: kernfs_node to search under 911bd96f76aSTejun Heo * @path: path to look for 912bd96f76aSTejun Heo * @ns: the namespace tag to use 913bd96f76aSTejun Heo * 914bd96f76aSTejun Heo * Look for kernfs_node with path @path under @parent and get a reference 915bd96f76aSTejun Heo * if found. This function may sleep and returns pointer to the found 916bd96f76aSTejun Heo * kernfs_node on success, %NULL on failure. 917bd96f76aSTejun Heo */ 918bd96f76aSTejun Heo struct kernfs_node *kernfs_walk_and_get_ns(struct kernfs_node *parent, 919bd96f76aSTejun Heo const char *path, const void *ns) 920bd96f76aSTejun Heo { 921bd96f76aSTejun Heo struct kernfs_node *kn; 922bd96f76aSTejun Heo 923bd96f76aSTejun Heo mutex_lock(&kernfs_mutex); 924bd96f76aSTejun Heo kn = kernfs_walk_ns(parent, path, ns); 925bd96f76aSTejun Heo kernfs_get(kn); 926bd96f76aSTejun Heo mutex_unlock(&kernfs_mutex); 927bd96f76aSTejun Heo 928bd96f76aSTejun Heo return kn; 929bd96f76aSTejun Heo } 930bd96f76aSTejun Heo 931bd96f76aSTejun Heo /** 932ba7443bcSTejun Heo * kernfs_create_root - create a new kernfs hierarchy 93390c07c89STejun Heo * @scops: optional syscall operations for the hierarchy 934d35258efSTejun Heo * @flags: KERNFS_ROOT_* flags 935ba7443bcSTejun Heo * @priv: opaque data associated with the new directory 936ba7443bcSTejun Heo * 937ba7443bcSTejun Heo * Returns the root of the new hierarchy on success, ERR_PTR() value on 938ba7443bcSTejun Heo * failure. 939ba7443bcSTejun Heo */ 94090c07c89STejun Heo struct kernfs_root *kernfs_create_root(struct kernfs_syscall_ops *scops, 941d35258efSTejun Heo unsigned int flags, void *priv) 942ba7443bcSTejun Heo { 943ba7443bcSTejun Heo struct kernfs_root *root; 944324a56e1STejun Heo struct kernfs_node *kn; 945ba7443bcSTejun Heo 946ba7443bcSTejun Heo root = kzalloc(sizeof(*root), GFP_KERNEL); 947ba7443bcSTejun Heo if (!root) 948ba7443bcSTejun Heo return ERR_PTR(-ENOMEM); 949ba7443bcSTejun Heo 9507d35079fSShaohua Li idr_init(&root->ino_idr); 9517d568a83STejun Heo INIT_LIST_HEAD(&root->supers); 9524a3ef68aSShaohua Li root->next_generation = 1; 953bc755553STejun Heo 954e19dfdc8SOndrej Mosnacek kn = __kernfs_new_node(root, NULL, "", S_IFDIR | S_IRUGO | S_IXUGO, 955488dee96SDmitry Torokhov GLOBAL_ROOT_UID, GLOBAL_ROOT_GID, 956db4aad20STejun Heo KERNFS_DIR); 957324a56e1STejun Heo if (!kn) { 9587d35079fSShaohua Li idr_destroy(&root->ino_idr); 959ba7443bcSTejun Heo kfree(root); 960ba7443bcSTejun Heo return ERR_PTR(-ENOMEM); 961ba7443bcSTejun Heo } 962ba7443bcSTejun Heo 963324a56e1STejun Heo kn->priv = priv; 964adc5e8b5STejun Heo kn->dir.root = root; 965ba7443bcSTejun Heo 96690c07c89STejun Heo root->syscall_ops = scops; 967d35258efSTejun Heo root->flags = flags; 968324a56e1STejun Heo root->kn = kn; 969abd54f02STejun Heo init_waitqueue_head(&root->deactivate_waitq); 970ba7443bcSTejun Heo 971d35258efSTejun Heo if (!(root->flags & KERNFS_ROOT_CREATE_DEACTIVATED)) 972d35258efSTejun Heo kernfs_activate(kn); 973d35258efSTejun Heo 974ba7443bcSTejun Heo return root; 975ba7443bcSTejun Heo } 976ba7443bcSTejun Heo 977ba7443bcSTejun Heo /** 978ba7443bcSTejun Heo * kernfs_destroy_root - destroy a kernfs hierarchy 979ba7443bcSTejun Heo * @root: root of the hierarchy to destroy 980ba7443bcSTejun Heo * 981ba7443bcSTejun Heo * Destroy the hierarchy anchored at @root by removing all existing 982ba7443bcSTejun Heo * directories and destroying @root. 983ba7443bcSTejun Heo */ 984ba7443bcSTejun Heo void kernfs_destroy_root(struct kernfs_root *root) 985ba7443bcSTejun Heo { 986324a56e1STejun Heo kernfs_remove(root->kn); /* will also free @root */ 987ba7443bcSTejun Heo } 988ba7443bcSTejun Heo 989ba7443bcSTejun Heo /** 990fd7b9f7bSTejun Heo * kernfs_create_dir_ns - create a directory 991fd7b9f7bSTejun Heo * @parent: parent in which to create a new directory 992fd7b9f7bSTejun Heo * @name: name of the new directory 993bb8b9d09STejun Heo * @mode: mode of the new directory 994488dee96SDmitry Torokhov * @uid: uid of the new directory 995488dee96SDmitry Torokhov * @gid: gid of the new directory 996fd7b9f7bSTejun Heo * @priv: opaque data associated with the new directory 997fd7b9f7bSTejun Heo * @ns: optional namespace tag of the directory 998fd7b9f7bSTejun Heo * 999fd7b9f7bSTejun Heo * Returns the created node on success, ERR_PTR() value on failure. 1000fd7b9f7bSTejun Heo */ 1001324a56e1STejun Heo struct kernfs_node *kernfs_create_dir_ns(struct kernfs_node *parent, 1002bb8b9d09STejun Heo const char *name, umode_t mode, 1003488dee96SDmitry Torokhov kuid_t uid, kgid_t gid, 1004bb8b9d09STejun Heo void *priv, const void *ns) 1005fd7b9f7bSTejun Heo { 1006324a56e1STejun Heo struct kernfs_node *kn; 1007fd7b9f7bSTejun Heo int rc; 1008fd7b9f7bSTejun Heo 1009fd7b9f7bSTejun Heo /* allocate */ 1010488dee96SDmitry Torokhov kn = kernfs_new_node(parent, name, mode | S_IFDIR, 1011488dee96SDmitry Torokhov uid, gid, KERNFS_DIR); 1012324a56e1STejun Heo if (!kn) 1013fd7b9f7bSTejun Heo return ERR_PTR(-ENOMEM); 1014fd7b9f7bSTejun Heo 1015adc5e8b5STejun Heo kn->dir.root = parent->dir.root; 1016adc5e8b5STejun Heo kn->ns = ns; 1017324a56e1STejun Heo kn->priv = priv; 1018fd7b9f7bSTejun Heo 1019fd7b9f7bSTejun Heo /* link in */ 1020988cd7afSTejun Heo rc = kernfs_add_one(kn); 1021fd7b9f7bSTejun Heo if (!rc) 1022324a56e1STejun Heo return kn; 1023fd7b9f7bSTejun Heo 1024324a56e1STejun Heo kernfs_put(kn); 1025fd7b9f7bSTejun Heo return ERR_PTR(rc); 1026fd7b9f7bSTejun Heo } 1027fd7b9f7bSTejun Heo 1028ea015218SEric W. Biederman /** 1029ea015218SEric W. Biederman * kernfs_create_empty_dir - create an always empty directory 1030ea015218SEric W. Biederman * @parent: parent in which to create a new directory 1031ea015218SEric W. Biederman * @name: name of the new directory 1032ea015218SEric W. Biederman * 1033ea015218SEric W. Biederman * Returns the created node on success, ERR_PTR() value on failure. 1034ea015218SEric W. Biederman */ 1035ea015218SEric W. Biederman struct kernfs_node *kernfs_create_empty_dir(struct kernfs_node *parent, 1036ea015218SEric W. Biederman const char *name) 1037ea015218SEric W. Biederman { 1038ea015218SEric W. Biederman struct kernfs_node *kn; 1039ea015218SEric W. Biederman int rc; 1040ea015218SEric W. Biederman 1041ea015218SEric W. Biederman /* allocate */ 1042488dee96SDmitry Torokhov kn = kernfs_new_node(parent, name, S_IRUGO|S_IXUGO|S_IFDIR, 1043488dee96SDmitry Torokhov GLOBAL_ROOT_UID, GLOBAL_ROOT_GID, KERNFS_DIR); 1044ea015218SEric W. Biederman if (!kn) 1045ea015218SEric W. Biederman return ERR_PTR(-ENOMEM); 1046ea015218SEric W. Biederman 1047ea015218SEric W. Biederman kn->flags |= KERNFS_EMPTY_DIR; 1048ea015218SEric W. Biederman kn->dir.root = parent->dir.root; 1049ea015218SEric W. Biederman kn->ns = NULL; 1050ea015218SEric W. Biederman kn->priv = NULL; 1051ea015218SEric W. Biederman 1052ea015218SEric W. Biederman /* link in */ 1053ea015218SEric W. Biederman rc = kernfs_add_one(kn); 1054ea015218SEric W. Biederman if (!rc) 1055ea015218SEric W. Biederman return kn; 1056ea015218SEric W. Biederman 1057ea015218SEric W. Biederman kernfs_put(kn); 1058ea015218SEric W. Biederman return ERR_PTR(rc); 1059ea015218SEric W. Biederman } 1060ea015218SEric W. Biederman 1061c637b8acSTejun Heo static struct dentry *kernfs_iop_lookup(struct inode *dir, 1062c637b8acSTejun Heo struct dentry *dentry, 1063fd7b9f7bSTejun Heo unsigned int flags) 1064fd7b9f7bSTejun Heo { 106519bbb926STejun Heo struct dentry *ret; 1066319ba91dSShaohua Li struct kernfs_node *parent = dir->i_private; 1067324a56e1STejun Heo struct kernfs_node *kn; 1068fd7b9f7bSTejun Heo struct inode *inode; 1069fd7b9f7bSTejun Heo const void *ns = NULL; 1070fd7b9f7bSTejun Heo 1071a797bfc3STejun Heo mutex_lock(&kernfs_mutex); 1072fd7b9f7bSTejun Heo 1073324a56e1STejun Heo if (kernfs_ns_enabled(parent)) 1074c525aaddSTejun Heo ns = kernfs_info(dir->i_sb)->ns; 1075fd7b9f7bSTejun Heo 1076324a56e1STejun Heo kn = kernfs_find_ns(parent, dentry->d_name.name, ns); 1077fd7b9f7bSTejun Heo 1078fd7b9f7bSTejun Heo /* no such entry */ 1079b9c9dad0STejun Heo if (!kn || !kernfs_active(kn)) { 108019bbb926STejun Heo ret = NULL; 1081fd7b9f7bSTejun Heo goto out_unlock; 1082fd7b9f7bSTejun Heo } 1083fd7b9f7bSTejun Heo 1084fd7b9f7bSTejun Heo /* attach dentry and inode */ 1085c637b8acSTejun Heo inode = kernfs_get_inode(dir->i_sb, kn); 1086fd7b9f7bSTejun Heo if (!inode) { 1087fd7b9f7bSTejun Heo ret = ERR_PTR(-ENOMEM); 1088fd7b9f7bSTejun Heo goto out_unlock; 1089fd7b9f7bSTejun Heo } 1090fd7b9f7bSTejun Heo 1091fd7b9f7bSTejun Heo /* instantiate and hash dentry */ 109241d28bcaSAl Viro ret = d_splice_alias(inode, dentry); 1093fd7b9f7bSTejun Heo out_unlock: 1094a797bfc3STejun Heo mutex_unlock(&kernfs_mutex); 1095fd7b9f7bSTejun Heo return ret; 1096fd7b9f7bSTejun Heo } 1097fd7b9f7bSTejun Heo 109880b9bbefSTejun Heo static int kernfs_iop_mkdir(struct inode *dir, struct dentry *dentry, 109980b9bbefSTejun Heo umode_t mode) 110080b9bbefSTejun Heo { 110180b9bbefSTejun Heo struct kernfs_node *parent = dir->i_private; 110290c07c89STejun Heo struct kernfs_syscall_ops *scops = kernfs_root(parent)->syscall_ops; 110307c7530dSTejun Heo int ret; 110480b9bbefSTejun Heo 110590c07c89STejun Heo if (!scops || !scops->mkdir) 110680b9bbefSTejun Heo return -EPERM; 110780b9bbefSTejun Heo 110807c7530dSTejun Heo if (!kernfs_get_active(parent)) 110907c7530dSTejun Heo return -ENODEV; 111007c7530dSTejun Heo 111190c07c89STejun Heo ret = scops->mkdir(parent, dentry->d_name.name, mode); 111207c7530dSTejun Heo 111307c7530dSTejun Heo kernfs_put_active(parent); 111407c7530dSTejun Heo return ret; 111580b9bbefSTejun Heo } 111680b9bbefSTejun Heo 111780b9bbefSTejun Heo static int kernfs_iop_rmdir(struct inode *dir, struct dentry *dentry) 111880b9bbefSTejun Heo { 1119319ba91dSShaohua Li struct kernfs_node *kn = kernfs_dentry_node(dentry); 112090c07c89STejun Heo struct kernfs_syscall_ops *scops = kernfs_root(kn)->syscall_ops; 112107c7530dSTejun Heo int ret; 112280b9bbefSTejun Heo 112390c07c89STejun Heo if (!scops || !scops->rmdir) 112480b9bbefSTejun Heo return -EPERM; 112580b9bbefSTejun Heo 112607c7530dSTejun Heo if (!kernfs_get_active(kn)) 112707c7530dSTejun Heo return -ENODEV; 112807c7530dSTejun Heo 112990c07c89STejun Heo ret = scops->rmdir(kn); 113007c7530dSTejun Heo 113107c7530dSTejun Heo kernfs_put_active(kn); 113207c7530dSTejun Heo return ret; 113380b9bbefSTejun Heo } 113480b9bbefSTejun Heo 113580b9bbefSTejun Heo static int kernfs_iop_rename(struct inode *old_dir, struct dentry *old_dentry, 11361cd66c93SMiklos Szeredi struct inode *new_dir, struct dentry *new_dentry, 11371cd66c93SMiklos Szeredi unsigned int flags) 113880b9bbefSTejun Heo { 1139319ba91dSShaohua Li struct kernfs_node *kn = kernfs_dentry_node(old_dentry); 114080b9bbefSTejun Heo struct kernfs_node *new_parent = new_dir->i_private; 114190c07c89STejun Heo struct kernfs_syscall_ops *scops = kernfs_root(kn)->syscall_ops; 114207c7530dSTejun Heo int ret; 114380b9bbefSTejun Heo 11441cd66c93SMiklos Szeredi if (flags) 11451cd66c93SMiklos Szeredi return -EINVAL; 11461cd66c93SMiklos Szeredi 114790c07c89STejun Heo if (!scops || !scops->rename) 114880b9bbefSTejun Heo return -EPERM; 114980b9bbefSTejun Heo 115007c7530dSTejun Heo if (!kernfs_get_active(kn)) 115107c7530dSTejun Heo return -ENODEV; 115207c7530dSTejun Heo 115307c7530dSTejun Heo if (!kernfs_get_active(new_parent)) { 115407c7530dSTejun Heo kernfs_put_active(kn); 115507c7530dSTejun Heo return -ENODEV; 115607c7530dSTejun Heo } 115707c7530dSTejun Heo 115890c07c89STejun Heo ret = scops->rename(kn, new_parent, new_dentry->d_name.name); 115907c7530dSTejun Heo 116007c7530dSTejun Heo kernfs_put_active(new_parent); 116107c7530dSTejun Heo kernfs_put_active(kn); 116207c7530dSTejun Heo return ret; 116380b9bbefSTejun Heo } 116480b9bbefSTejun Heo 1165a797bfc3STejun Heo const struct inode_operations kernfs_dir_iops = { 1166c637b8acSTejun Heo .lookup = kernfs_iop_lookup, 1167c637b8acSTejun Heo .permission = kernfs_iop_permission, 1168c637b8acSTejun Heo .setattr = kernfs_iop_setattr, 1169c637b8acSTejun Heo .getattr = kernfs_iop_getattr, 1170c637b8acSTejun Heo .listxattr = kernfs_iop_listxattr, 117180b9bbefSTejun Heo 117280b9bbefSTejun Heo .mkdir = kernfs_iop_mkdir, 117380b9bbefSTejun Heo .rmdir = kernfs_iop_rmdir, 117480b9bbefSTejun Heo .rename = kernfs_iop_rename, 1175fd7b9f7bSTejun Heo }; 1176fd7b9f7bSTejun Heo 1177c637b8acSTejun Heo static struct kernfs_node *kernfs_leftmost_descendant(struct kernfs_node *pos) 1178fd7b9f7bSTejun Heo { 1179324a56e1STejun Heo struct kernfs_node *last; 1180fd7b9f7bSTejun Heo 1181fd7b9f7bSTejun Heo while (true) { 1182fd7b9f7bSTejun Heo struct rb_node *rbn; 1183fd7b9f7bSTejun Heo 1184fd7b9f7bSTejun Heo last = pos; 1185fd7b9f7bSTejun Heo 1186df23fc39STejun Heo if (kernfs_type(pos) != KERNFS_DIR) 1187fd7b9f7bSTejun Heo break; 1188fd7b9f7bSTejun Heo 1189adc5e8b5STejun Heo rbn = rb_first(&pos->dir.children); 1190fd7b9f7bSTejun Heo if (!rbn) 1191fd7b9f7bSTejun Heo break; 1192fd7b9f7bSTejun Heo 1193324a56e1STejun Heo pos = rb_to_kn(rbn); 1194fd7b9f7bSTejun Heo } 1195fd7b9f7bSTejun Heo 1196fd7b9f7bSTejun Heo return last; 1197fd7b9f7bSTejun Heo } 1198fd7b9f7bSTejun Heo 1199fd7b9f7bSTejun Heo /** 1200c637b8acSTejun Heo * kernfs_next_descendant_post - find the next descendant for post-order walk 1201fd7b9f7bSTejun Heo * @pos: the current position (%NULL to initiate traversal) 1202324a56e1STejun Heo * @root: kernfs_node whose descendants to walk 1203fd7b9f7bSTejun Heo * 1204fd7b9f7bSTejun Heo * Find the next descendant to visit for post-order traversal of @root's 1205fd7b9f7bSTejun Heo * descendants. @root is included in the iteration and the last node to be 1206fd7b9f7bSTejun Heo * visited. 1207fd7b9f7bSTejun Heo */ 1208c637b8acSTejun Heo static struct kernfs_node *kernfs_next_descendant_post(struct kernfs_node *pos, 1209324a56e1STejun Heo struct kernfs_node *root) 1210fd7b9f7bSTejun Heo { 1211fd7b9f7bSTejun Heo struct rb_node *rbn; 1212fd7b9f7bSTejun Heo 1213a797bfc3STejun Heo lockdep_assert_held(&kernfs_mutex); 1214fd7b9f7bSTejun Heo 1215fd7b9f7bSTejun Heo /* if first iteration, visit leftmost descendant which may be root */ 1216fd7b9f7bSTejun Heo if (!pos) 1217c637b8acSTejun Heo return kernfs_leftmost_descendant(root); 1218fd7b9f7bSTejun Heo 1219fd7b9f7bSTejun Heo /* if we visited @root, we're done */ 1220fd7b9f7bSTejun Heo if (pos == root) 1221fd7b9f7bSTejun Heo return NULL; 1222fd7b9f7bSTejun Heo 1223fd7b9f7bSTejun Heo /* if there's an unvisited sibling, visit its leftmost descendant */ 1224adc5e8b5STejun Heo rbn = rb_next(&pos->rb); 1225fd7b9f7bSTejun Heo if (rbn) 1226c637b8acSTejun Heo return kernfs_leftmost_descendant(rb_to_kn(rbn)); 1227fd7b9f7bSTejun Heo 1228fd7b9f7bSTejun Heo /* no sibling left, visit parent */ 1229adc5e8b5STejun Heo return pos->parent; 1230fd7b9f7bSTejun Heo } 1231fd7b9f7bSTejun Heo 1232d35258efSTejun Heo /** 1233d35258efSTejun Heo * kernfs_activate - activate a node which started deactivated 1234d35258efSTejun Heo * @kn: kernfs_node whose subtree is to be activated 1235d35258efSTejun Heo * 1236d35258efSTejun Heo * If the root has KERNFS_ROOT_CREATE_DEACTIVATED set, a newly created node 1237d35258efSTejun Heo * needs to be explicitly activated. A node which hasn't been activated 1238d35258efSTejun Heo * isn't visible to userland and deactivation is skipped during its 1239d35258efSTejun Heo * removal. This is useful to construct atomic init sequences where 1240d35258efSTejun Heo * creation of multiple nodes should either succeed or fail atomically. 1241d35258efSTejun Heo * 1242d35258efSTejun Heo * The caller is responsible for ensuring that this function is not called 1243d35258efSTejun Heo * after kernfs_remove*() is invoked on @kn. 1244d35258efSTejun Heo */ 1245d35258efSTejun Heo void kernfs_activate(struct kernfs_node *kn) 1246d35258efSTejun Heo { 1247d35258efSTejun Heo struct kernfs_node *pos; 1248d35258efSTejun Heo 1249d35258efSTejun Heo mutex_lock(&kernfs_mutex); 1250d35258efSTejun Heo 1251d35258efSTejun Heo pos = NULL; 1252d35258efSTejun Heo while ((pos = kernfs_next_descendant_post(pos, kn))) { 1253d35258efSTejun Heo if (!pos || (pos->flags & KERNFS_ACTIVATED)) 1254d35258efSTejun Heo continue; 1255d35258efSTejun Heo 1256d35258efSTejun Heo WARN_ON_ONCE(pos->parent && RB_EMPTY_NODE(&pos->rb)); 1257d35258efSTejun Heo WARN_ON_ONCE(atomic_read(&pos->active) != KN_DEACTIVATED_BIAS); 1258d35258efSTejun Heo 1259d35258efSTejun Heo atomic_sub(KN_DEACTIVATED_BIAS, &pos->active); 1260d35258efSTejun Heo pos->flags |= KERNFS_ACTIVATED; 1261d35258efSTejun Heo } 1262d35258efSTejun Heo 1263d35258efSTejun Heo mutex_unlock(&kernfs_mutex); 1264d35258efSTejun Heo } 1265d35258efSTejun Heo 1266988cd7afSTejun Heo static void __kernfs_remove(struct kernfs_node *kn) 1267fd7b9f7bSTejun Heo { 126835beab06STejun Heo struct kernfs_node *pos; 126935beab06STejun Heo 127035beab06STejun Heo lockdep_assert_held(&kernfs_mutex); 1271fd7b9f7bSTejun Heo 12726b0afc2aSTejun Heo /* 12736b0afc2aSTejun Heo * Short-circuit if non-root @kn has already finished removal. 12746b0afc2aSTejun Heo * This is for kernfs_remove_self() which plays with active ref 12756b0afc2aSTejun Heo * after removal. 12766b0afc2aSTejun Heo */ 12776b0afc2aSTejun Heo if (!kn || (kn->parent && RB_EMPTY_NODE(&kn->rb))) 1278ce9b499cSGreg Kroah-Hartman return; 1279ce9b499cSGreg Kroah-Hartman 1280c637b8acSTejun Heo pr_debug("kernfs %s: removing\n", kn->name); 1281fd7b9f7bSTejun Heo 128281c173cbSTejun Heo /* prevent any new usage under @kn by deactivating all nodes */ 128335beab06STejun Heo pos = NULL; 128435beab06STejun Heo while ((pos = kernfs_next_descendant_post(pos, kn))) 128581c173cbSTejun Heo if (kernfs_active(pos)) 128681c173cbSTejun Heo atomic_add(KN_DEACTIVATED_BIAS, &pos->active); 128735beab06STejun Heo 128835beab06STejun Heo /* deactivate and unlink the subtree node-by-node */ 1289fd7b9f7bSTejun Heo do { 129035beab06STejun Heo pos = kernfs_leftmost_descendant(kn); 129135beab06STejun Heo 129235beab06STejun Heo /* 129381c173cbSTejun Heo * kernfs_drain() drops kernfs_mutex temporarily and @pos's 129481c173cbSTejun Heo * base ref could have been put by someone else by the time 129581c173cbSTejun Heo * the function returns. Make sure it doesn't go away 129681c173cbSTejun Heo * underneath us. 129735beab06STejun Heo */ 129835beab06STejun Heo kernfs_get(pos); 129935beab06STejun Heo 1300d35258efSTejun Heo /* 1301d35258efSTejun Heo * Drain iff @kn was activated. This avoids draining and 1302d35258efSTejun Heo * its lockdep annotations for nodes which have never been 1303d35258efSTejun Heo * activated and allows embedding kernfs_remove() in create 1304d35258efSTejun Heo * error paths without worrying about draining. 1305d35258efSTejun Heo */ 1306d35258efSTejun Heo if (kn->flags & KERNFS_ACTIVATED) 130781c173cbSTejun Heo kernfs_drain(pos); 1308d35258efSTejun Heo else 1309d35258efSTejun Heo WARN_ON_ONCE(atomic_read(&kn->active) != KN_DEACTIVATED_BIAS); 131035beab06STejun Heo 131135beab06STejun Heo /* 131235beab06STejun Heo * kernfs_unlink_sibling() succeeds once per node. Use it 131335beab06STejun Heo * to decide who's responsible for cleanups. 131435beab06STejun Heo */ 131535beab06STejun Heo if (!pos->parent || kernfs_unlink_sibling(pos)) { 131635beab06STejun Heo struct kernfs_iattrs *ps_iattr = 131735beab06STejun Heo pos->parent ? pos->parent->iattr : NULL; 131835beab06STejun Heo 131935beab06STejun Heo /* update timestamps on the parent */ 132035beab06STejun Heo if (ps_iattr) { 132105895219SOndrej Mosnacek ktime_get_real_ts64(&ps_iattr->ia_ctime); 132205895219SOndrej Mosnacek ps_iattr->ia_mtime = ps_iattr->ia_ctime; 132335beab06STejun Heo } 132435beab06STejun Heo 1325988cd7afSTejun Heo kernfs_put(pos); 132635beab06STejun Heo } 132735beab06STejun Heo 132835beab06STejun Heo kernfs_put(pos); 132935beab06STejun Heo } while (pos != kn); 1330fd7b9f7bSTejun Heo } 1331fd7b9f7bSTejun Heo 1332fd7b9f7bSTejun Heo /** 1333324a56e1STejun Heo * kernfs_remove - remove a kernfs_node recursively 1334324a56e1STejun Heo * @kn: the kernfs_node to remove 1335fd7b9f7bSTejun Heo * 1336324a56e1STejun Heo * Remove @kn along with all its subdirectories and files. 1337fd7b9f7bSTejun Heo */ 1338324a56e1STejun Heo void kernfs_remove(struct kernfs_node *kn) 1339fd7b9f7bSTejun Heo { 1340988cd7afSTejun Heo mutex_lock(&kernfs_mutex); 1341988cd7afSTejun Heo __kernfs_remove(kn); 1342988cd7afSTejun Heo mutex_unlock(&kernfs_mutex); 1343fd7b9f7bSTejun Heo } 1344fd7b9f7bSTejun Heo 1345fd7b9f7bSTejun Heo /** 13466b0afc2aSTejun Heo * kernfs_break_active_protection - break out of active protection 13476b0afc2aSTejun Heo * @kn: the self kernfs_node 13486b0afc2aSTejun Heo * 13496b0afc2aSTejun Heo * The caller must be running off of a kernfs operation which is invoked 13506b0afc2aSTejun Heo * with an active reference - e.g. one of kernfs_ops. Each invocation of 13516b0afc2aSTejun Heo * this function must also be matched with an invocation of 13526b0afc2aSTejun Heo * kernfs_unbreak_active_protection(). 13536b0afc2aSTejun Heo * 13546b0afc2aSTejun Heo * This function releases the active reference of @kn the caller is 13556b0afc2aSTejun Heo * holding. Once this function is called, @kn may be removed at any point 13566b0afc2aSTejun Heo * and the caller is solely responsible for ensuring that the objects it 13576b0afc2aSTejun Heo * dereferences are accessible. 13586b0afc2aSTejun Heo */ 13596b0afc2aSTejun Heo void kernfs_break_active_protection(struct kernfs_node *kn) 13606b0afc2aSTejun Heo { 13616b0afc2aSTejun Heo /* 13626b0afc2aSTejun Heo * Take out ourself out of the active ref dependency chain. If 13636b0afc2aSTejun Heo * we're called without an active ref, lockdep will complain. 13646b0afc2aSTejun Heo */ 13656b0afc2aSTejun Heo kernfs_put_active(kn); 13666b0afc2aSTejun Heo } 13676b0afc2aSTejun Heo 13686b0afc2aSTejun Heo /** 13696b0afc2aSTejun Heo * kernfs_unbreak_active_protection - undo kernfs_break_active_protection() 13706b0afc2aSTejun Heo * @kn: the self kernfs_node 13716b0afc2aSTejun Heo * 13726b0afc2aSTejun Heo * If kernfs_break_active_protection() was called, this function must be 13736b0afc2aSTejun Heo * invoked before finishing the kernfs operation. Note that while this 13746b0afc2aSTejun Heo * function restores the active reference, it doesn't and can't actually 13756b0afc2aSTejun Heo * restore the active protection - @kn may already or be in the process of 13766b0afc2aSTejun Heo * being removed. Once kernfs_break_active_protection() is invoked, that 13776b0afc2aSTejun Heo * protection is irreversibly gone for the kernfs operation instance. 13786b0afc2aSTejun Heo * 13796b0afc2aSTejun Heo * While this function may be called at any point after 13806b0afc2aSTejun Heo * kernfs_break_active_protection() is invoked, its most useful location 13816b0afc2aSTejun Heo * would be right before the enclosing kernfs operation returns. 13826b0afc2aSTejun Heo */ 13836b0afc2aSTejun Heo void kernfs_unbreak_active_protection(struct kernfs_node *kn) 13846b0afc2aSTejun Heo { 13856b0afc2aSTejun Heo /* 13866b0afc2aSTejun Heo * @kn->active could be in any state; however, the increment we do 13876b0afc2aSTejun Heo * here will be undone as soon as the enclosing kernfs operation 13886b0afc2aSTejun Heo * finishes and this temporary bump can't break anything. If @kn 13896b0afc2aSTejun Heo * is alive, nothing changes. If @kn is being deactivated, the 13906b0afc2aSTejun Heo * soon-to-follow put will either finish deactivation or restore 13916b0afc2aSTejun Heo * deactivated state. If @kn is already removed, the temporary 13926b0afc2aSTejun Heo * bump is guaranteed to be gone before @kn is released. 13936b0afc2aSTejun Heo */ 13946b0afc2aSTejun Heo atomic_inc(&kn->active); 13956b0afc2aSTejun Heo if (kernfs_lockdep(kn)) 13966b0afc2aSTejun Heo rwsem_acquire(&kn->dep_map, 0, 1, _RET_IP_); 13976b0afc2aSTejun Heo } 13986b0afc2aSTejun Heo 13996b0afc2aSTejun Heo /** 14006b0afc2aSTejun Heo * kernfs_remove_self - remove a kernfs_node from its own method 14016b0afc2aSTejun Heo * @kn: the self kernfs_node to remove 14026b0afc2aSTejun Heo * 14036b0afc2aSTejun Heo * The caller must be running off of a kernfs operation which is invoked 14046b0afc2aSTejun Heo * with an active reference - e.g. one of kernfs_ops. This can be used to 14056b0afc2aSTejun Heo * implement a file operation which deletes itself. 14066b0afc2aSTejun Heo * 14076b0afc2aSTejun Heo * For example, the "delete" file for a sysfs device directory can be 14086b0afc2aSTejun Heo * implemented by invoking kernfs_remove_self() on the "delete" file 14096b0afc2aSTejun Heo * itself. This function breaks the circular dependency of trying to 14106b0afc2aSTejun Heo * deactivate self while holding an active ref itself. It isn't necessary 14116b0afc2aSTejun Heo * to modify the usual removal path to use kernfs_remove_self(). The 14126b0afc2aSTejun Heo * "delete" implementation can simply invoke kernfs_remove_self() on self 14136b0afc2aSTejun Heo * before proceeding with the usual removal path. kernfs will ignore later 14146b0afc2aSTejun Heo * kernfs_remove() on self. 14156b0afc2aSTejun Heo * 14166b0afc2aSTejun Heo * kernfs_remove_self() can be called multiple times concurrently on the 14176b0afc2aSTejun Heo * same kernfs_node. Only the first one actually performs removal and 14186b0afc2aSTejun Heo * returns %true. All others will wait until the kernfs operation which 14196b0afc2aSTejun Heo * won self-removal finishes and return %false. Note that the losers wait 14206b0afc2aSTejun Heo * for the completion of not only the winning kernfs_remove_self() but also 14216b0afc2aSTejun Heo * the whole kernfs_ops which won the arbitration. This can be used to 14226b0afc2aSTejun Heo * guarantee, for example, all concurrent writes to a "delete" file to 14236b0afc2aSTejun Heo * finish only after the whole operation is complete. 14246b0afc2aSTejun Heo */ 14256b0afc2aSTejun Heo bool kernfs_remove_self(struct kernfs_node *kn) 14266b0afc2aSTejun Heo { 14276b0afc2aSTejun Heo bool ret; 14286b0afc2aSTejun Heo 14296b0afc2aSTejun Heo mutex_lock(&kernfs_mutex); 14306b0afc2aSTejun Heo kernfs_break_active_protection(kn); 14316b0afc2aSTejun Heo 14326b0afc2aSTejun Heo /* 14336b0afc2aSTejun Heo * SUICIDAL is used to arbitrate among competing invocations. Only 14346b0afc2aSTejun Heo * the first one will actually perform removal. When the removal 14356b0afc2aSTejun Heo * is complete, SUICIDED is set and the active ref is restored 14366b0afc2aSTejun Heo * while holding kernfs_mutex. The ones which lost arbitration 14376b0afc2aSTejun Heo * waits for SUICDED && drained which can happen only after the 14386b0afc2aSTejun Heo * enclosing kernfs operation which executed the winning instance 14396b0afc2aSTejun Heo * of kernfs_remove_self() finished. 14406b0afc2aSTejun Heo */ 14416b0afc2aSTejun Heo if (!(kn->flags & KERNFS_SUICIDAL)) { 14426b0afc2aSTejun Heo kn->flags |= KERNFS_SUICIDAL; 14436b0afc2aSTejun Heo __kernfs_remove(kn); 14446b0afc2aSTejun Heo kn->flags |= KERNFS_SUICIDED; 14456b0afc2aSTejun Heo ret = true; 14466b0afc2aSTejun Heo } else { 14476b0afc2aSTejun Heo wait_queue_head_t *waitq = &kernfs_root(kn)->deactivate_waitq; 14486b0afc2aSTejun Heo DEFINE_WAIT(wait); 14496b0afc2aSTejun Heo 14506b0afc2aSTejun Heo while (true) { 14516b0afc2aSTejun Heo prepare_to_wait(waitq, &wait, TASK_UNINTERRUPTIBLE); 14526b0afc2aSTejun Heo 14536b0afc2aSTejun Heo if ((kn->flags & KERNFS_SUICIDED) && 14546b0afc2aSTejun Heo atomic_read(&kn->active) == KN_DEACTIVATED_BIAS) 14556b0afc2aSTejun Heo break; 14566b0afc2aSTejun Heo 14576b0afc2aSTejun Heo mutex_unlock(&kernfs_mutex); 14586b0afc2aSTejun Heo schedule(); 14596b0afc2aSTejun Heo mutex_lock(&kernfs_mutex); 14606b0afc2aSTejun Heo } 14616b0afc2aSTejun Heo finish_wait(waitq, &wait); 14626b0afc2aSTejun Heo WARN_ON_ONCE(!RB_EMPTY_NODE(&kn->rb)); 14636b0afc2aSTejun Heo ret = false; 14646b0afc2aSTejun Heo } 14656b0afc2aSTejun Heo 14666b0afc2aSTejun Heo /* 14676b0afc2aSTejun Heo * This must be done while holding kernfs_mutex; otherwise, waiting 14686b0afc2aSTejun Heo * for SUICIDED && deactivated could finish prematurely. 14696b0afc2aSTejun Heo */ 14706b0afc2aSTejun Heo kernfs_unbreak_active_protection(kn); 14716b0afc2aSTejun Heo 14726b0afc2aSTejun Heo mutex_unlock(&kernfs_mutex); 14736b0afc2aSTejun Heo return ret; 14746b0afc2aSTejun Heo } 14756b0afc2aSTejun Heo 14766b0afc2aSTejun Heo /** 1477324a56e1STejun Heo * kernfs_remove_by_name_ns - find a kernfs_node by name and remove it 1478324a56e1STejun Heo * @parent: parent of the target 1479324a56e1STejun Heo * @name: name of the kernfs_node to remove 1480324a56e1STejun Heo * @ns: namespace tag of the kernfs_node to remove 1481fd7b9f7bSTejun Heo * 1482324a56e1STejun Heo * Look for the kernfs_node with @name and @ns under @parent and remove it. 1483324a56e1STejun Heo * Returns 0 on success, -ENOENT if such entry doesn't exist. 1484fd7b9f7bSTejun Heo */ 1485324a56e1STejun Heo int kernfs_remove_by_name_ns(struct kernfs_node *parent, const char *name, 1486fd7b9f7bSTejun Heo const void *ns) 1487fd7b9f7bSTejun Heo { 1488324a56e1STejun Heo struct kernfs_node *kn; 1489fd7b9f7bSTejun Heo 1490324a56e1STejun Heo if (!parent) { 1491c637b8acSTejun Heo WARN(1, KERN_WARNING "kernfs: can not remove '%s', no directory\n", 1492fd7b9f7bSTejun Heo name); 1493fd7b9f7bSTejun Heo return -ENOENT; 1494fd7b9f7bSTejun Heo } 1495fd7b9f7bSTejun Heo 1496988cd7afSTejun Heo mutex_lock(&kernfs_mutex); 1497fd7b9f7bSTejun Heo 1498324a56e1STejun Heo kn = kernfs_find_ns(parent, name, ns); 1499324a56e1STejun Heo if (kn) 1500988cd7afSTejun Heo __kernfs_remove(kn); 1501fd7b9f7bSTejun Heo 1502988cd7afSTejun Heo mutex_unlock(&kernfs_mutex); 1503fd7b9f7bSTejun Heo 1504324a56e1STejun Heo if (kn) 1505fd7b9f7bSTejun Heo return 0; 1506fd7b9f7bSTejun Heo else 1507fd7b9f7bSTejun Heo return -ENOENT; 1508fd7b9f7bSTejun Heo } 1509fd7b9f7bSTejun Heo 1510fd7b9f7bSTejun Heo /** 1511fd7b9f7bSTejun Heo * kernfs_rename_ns - move and rename a kernfs_node 1512324a56e1STejun Heo * @kn: target node 1513fd7b9f7bSTejun Heo * @new_parent: new parent to put @sd under 1514fd7b9f7bSTejun Heo * @new_name: new name 1515fd7b9f7bSTejun Heo * @new_ns: new namespace tag 1516fd7b9f7bSTejun Heo */ 1517324a56e1STejun Heo int kernfs_rename_ns(struct kernfs_node *kn, struct kernfs_node *new_parent, 1518fd7b9f7bSTejun Heo const char *new_name, const void *new_ns) 1519fd7b9f7bSTejun Heo { 15203eef34adSTejun Heo struct kernfs_node *old_parent; 15213eef34adSTejun Heo const char *old_name = NULL; 1522fd7b9f7bSTejun Heo int error; 1523fd7b9f7bSTejun Heo 15243eef34adSTejun Heo /* can't move or rename root */ 15253eef34adSTejun Heo if (!kn->parent) 15263eef34adSTejun Heo return -EINVAL; 15273eef34adSTejun Heo 1528ae34372eSTejun Heo mutex_lock(&kernfs_mutex); 1529d0ae3d43STejun Heo 1530798c75a0SGreg Kroah-Hartman error = -ENOENT; 1531ea015218SEric W. Biederman if (!kernfs_active(kn) || !kernfs_active(new_parent) || 1532ea015218SEric W. Biederman (new_parent->flags & KERNFS_EMPTY_DIR)) 1533798c75a0SGreg Kroah-Hartman goto out; 1534798c75a0SGreg Kroah-Hartman 1535fd7b9f7bSTejun Heo error = 0; 1536adc5e8b5STejun Heo if ((kn->parent == new_parent) && (kn->ns == new_ns) && 1537adc5e8b5STejun Heo (strcmp(kn->name, new_name) == 0)) 1538798c75a0SGreg Kroah-Hartman goto out; /* nothing to rename */ 1539fd7b9f7bSTejun Heo 1540fd7b9f7bSTejun Heo error = -EEXIST; 1541fd7b9f7bSTejun Heo if (kernfs_find_ns(new_parent, new_name, new_ns)) 1542798c75a0SGreg Kroah-Hartman goto out; 1543fd7b9f7bSTejun Heo 1544324a56e1STejun Heo /* rename kernfs_node */ 1545adc5e8b5STejun Heo if (strcmp(kn->name, new_name) != 0) { 1546fd7b9f7bSTejun Heo error = -ENOMEM; 154775287a67SAndrzej Hajda new_name = kstrdup_const(new_name, GFP_KERNEL); 1548fd7b9f7bSTejun Heo if (!new_name) 1549798c75a0SGreg Kroah-Hartman goto out; 15503eef34adSTejun Heo } else { 15513eef34adSTejun Heo new_name = NULL; 1552fd7b9f7bSTejun Heo } 1553fd7b9f7bSTejun Heo 1554fd7b9f7bSTejun Heo /* 1555fd7b9f7bSTejun Heo * Move to the appropriate place in the appropriate directories rbtree. 1556fd7b9f7bSTejun Heo */ 1557c637b8acSTejun Heo kernfs_unlink_sibling(kn); 1558fd7b9f7bSTejun Heo kernfs_get(new_parent); 15593eef34adSTejun Heo 15603eef34adSTejun Heo /* rename_lock protects ->parent and ->name accessors */ 15613eef34adSTejun Heo spin_lock_irq(&kernfs_rename_lock); 15623eef34adSTejun Heo 15633eef34adSTejun Heo old_parent = kn->parent; 1564adc5e8b5STejun Heo kn->parent = new_parent; 15653eef34adSTejun Heo 15663eef34adSTejun Heo kn->ns = new_ns; 15673eef34adSTejun Heo if (new_name) { 15683eef34adSTejun Heo old_name = kn->name; 15693eef34adSTejun Heo kn->name = new_name; 15703eef34adSTejun Heo } 15713eef34adSTejun Heo 15723eef34adSTejun Heo spin_unlock_irq(&kernfs_rename_lock); 15733eef34adSTejun Heo 15749561a896STejun Heo kn->hash = kernfs_name_hash(kn->name, kn->ns); 1575c637b8acSTejun Heo kernfs_link_sibling(kn); 1576fd7b9f7bSTejun Heo 15773eef34adSTejun Heo kernfs_put(old_parent); 157875287a67SAndrzej Hajda kfree_const(old_name); 15793eef34adSTejun Heo 1580fd7b9f7bSTejun Heo error = 0; 1581ae34372eSTejun Heo out: 1582798c75a0SGreg Kroah-Hartman mutex_unlock(&kernfs_mutex); 1583fd7b9f7bSTejun Heo return error; 1584fd7b9f7bSTejun Heo } 1585fd7b9f7bSTejun Heo 1586fd7b9f7bSTejun Heo /* Relationship between s_mode and the DT_xxx types */ 1587324a56e1STejun Heo static inline unsigned char dt_type(struct kernfs_node *kn) 1588fd7b9f7bSTejun Heo { 1589adc5e8b5STejun Heo return (kn->mode >> 12) & 15; 1590fd7b9f7bSTejun Heo } 1591fd7b9f7bSTejun Heo 1592c637b8acSTejun Heo static int kernfs_dir_fop_release(struct inode *inode, struct file *filp) 1593fd7b9f7bSTejun Heo { 1594fd7b9f7bSTejun Heo kernfs_put(filp->private_data); 1595fd7b9f7bSTejun Heo return 0; 1596fd7b9f7bSTejun Heo } 1597fd7b9f7bSTejun Heo 1598c637b8acSTejun Heo static struct kernfs_node *kernfs_dir_pos(const void *ns, 1599324a56e1STejun Heo struct kernfs_node *parent, loff_t hash, struct kernfs_node *pos) 1600fd7b9f7bSTejun Heo { 1601fd7b9f7bSTejun Heo if (pos) { 160281c173cbSTejun Heo int valid = kernfs_active(pos) && 1603798c75a0SGreg Kroah-Hartman pos->parent == parent && hash == pos->hash; 1604fd7b9f7bSTejun Heo kernfs_put(pos); 1605fd7b9f7bSTejun Heo if (!valid) 1606fd7b9f7bSTejun Heo pos = NULL; 1607fd7b9f7bSTejun Heo } 1608fd7b9f7bSTejun Heo if (!pos && (hash > 1) && (hash < INT_MAX)) { 1609adc5e8b5STejun Heo struct rb_node *node = parent->dir.children.rb_node; 1610fd7b9f7bSTejun Heo while (node) { 1611324a56e1STejun Heo pos = rb_to_kn(node); 1612fd7b9f7bSTejun Heo 1613adc5e8b5STejun Heo if (hash < pos->hash) 1614fd7b9f7bSTejun Heo node = node->rb_left; 1615adc5e8b5STejun Heo else if (hash > pos->hash) 1616fd7b9f7bSTejun Heo node = node->rb_right; 1617fd7b9f7bSTejun Heo else 1618fd7b9f7bSTejun Heo break; 1619fd7b9f7bSTejun Heo } 1620fd7b9f7bSTejun Heo } 1621b9c9dad0STejun Heo /* Skip over entries which are dying/dead or in the wrong namespace */ 1622b9c9dad0STejun Heo while (pos && (!kernfs_active(pos) || pos->ns != ns)) { 1623adc5e8b5STejun Heo struct rb_node *node = rb_next(&pos->rb); 1624fd7b9f7bSTejun Heo if (!node) 1625fd7b9f7bSTejun Heo pos = NULL; 1626fd7b9f7bSTejun Heo else 1627324a56e1STejun Heo pos = rb_to_kn(node); 1628fd7b9f7bSTejun Heo } 1629fd7b9f7bSTejun Heo return pos; 1630fd7b9f7bSTejun Heo } 1631fd7b9f7bSTejun Heo 1632c637b8acSTejun Heo static struct kernfs_node *kernfs_dir_next_pos(const void *ns, 1633324a56e1STejun Heo struct kernfs_node *parent, ino_t ino, struct kernfs_node *pos) 1634fd7b9f7bSTejun Heo { 1635c637b8acSTejun Heo pos = kernfs_dir_pos(ns, parent, ino, pos); 1636b9c9dad0STejun Heo if (pos) { 1637fd7b9f7bSTejun Heo do { 1638adc5e8b5STejun Heo struct rb_node *node = rb_next(&pos->rb); 1639fd7b9f7bSTejun Heo if (!node) 1640fd7b9f7bSTejun Heo pos = NULL; 1641fd7b9f7bSTejun Heo else 1642324a56e1STejun Heo pos = rb_to_kn(node); 1643b9c9dad0STejun Heo } while (pos && (!kernfs_active(pos) || pos->ns != ns)); 1644b9c9dad0STejun Heo } 1645fd7b9f7bSTejun Heo return pos; 1646fd7b9f7bSTejun Heo } 1647fd7b9f7bSTejun Heo 1648c637b8acSTejun Heo static int kernfs_fop_readdir(struct file *file, struct dir_context *ctx) 1649fd7b9f7bSTejun Heo { 1650fd7b9f7bSTejun Heo struct dentry *dentry = file->f_path.dentry; 1651319ba91dSShaohua Li struct kernfs_node *parent = kernfs_dentry_node(dentry); 1652324a56e1STejun Heo struct kernfs_node *pos = file->private_data; 1653fd7b9f7bSTejun Heo const void *ns = NULL; 1654fd7b9f7bSTejun Heo 1655fd7b9f7bSTejun Heo if (!dir_emit_dots(file, ctx)) 1656fd7b9f7bSTejun Heo return 0; 1657a797bfc3STejun Heo mutex_lock(&kernfs_mutex); 1658fd7b9f7bSTejun Heo 1659324a56e1STejun Heo if (kernfs_ns_enabled(parent)) 1660c525aaddSTejun Heo ns = kernfs_info(dentry->d_sb)->ns; 1661fd7b9f7bSTejun Heo 1662c637b8acSTejun Heo for (pos = kernfs_dir_pos(ns, parent, ctx->pos, pos); 1663fd7b9f7bSTejun Heo pos; 1664c637b8acSTejun Heo pos = kernfs_dir_next_pos(ns, parent, ctx->pos, pos)) { 1665adc5e8b5STejun Heo const char *name = pos->name; 1666fd7b9f7bSTejun Heo unsigned int type = dt_type(pos); 1667fd7b9f7bSTejun Heo int len = strlen(name); 166867c0496eSTejun Heo ino_t ino = kernfs_ino(pos); 1669fd7b9f7bSTejun Heo 1670adc5e8b5STejun Heo ctx->pos = pos->hash; 1671fd7b9f7bSTejun Heo file->private_data = pos; 1672fd7b9f7bSTejun Heo kernfs_get(pos); 1673fd7b9f7bSTejun Heo 1674a797bfc3STejun Heo mutex_unlock(&kernfs_mutex); 1675fd7b9f7bSTejun Heo if (!dir_emit(ctx, name, len, ino, type)) 1676fd7b9f7bSTejun Heo return 0; 1677a797bfc3STejun Heo mutex_lock(&kernfs_mutex); 1678fd7b9f7bSTejun Heo } 1679a797bfc3STejun Heo mutex_unlock(&kernfs_mutex); 1680fd7b9f7bSTejun Heo file->private_data = NULL; 1681fd7b9f7bSTejun Heo ctx->pos = INT_MAX; 1682fd7b9f7bSTejun Heo return 0; 1683fd7b9f7bSTejun Heo } 1684fd7b9f7bSTejun Heo 1685a797bfc3STejun Heo const struct file_operations kernfs_dir_fops = { 1686fd7b9f7bSTejun Heo .read = generic_read_dir, 16878cb0d2c1SAl Viro .iterate_shared = kernfs_fop_readdir, 1688c637b8acSTejun Heo .release = kernfs_dir_fop_release, 16898cb0d2c1SAl Viro .llseek = generic_file_llseek, 1690fd7b9f7bSTejun Heo }; 1691