1b8441ed2STejun Heo /* 2b8441ed2STejun Heo * fs/kernfs/dir.c - kernfs directory implementation 3b8441ed2STejun Heo * 4b8441ed2STejun Heo * Copyright (c) 2001-3 Patrick Mochel 5b8441ed2STejun Heo * Copyright (c) 2007 SUSE Linux Products GmbH 6b8441ed2STejun Heo * Copyright (c) 2007, 2013 Tejun Heo <tj@kernel.org> 7b8441ed2STejun Heo * 8b8441ed2STejun Heo * This file is released under the GPLv2. 9b8441ed2STejun Heo */ 10fd7b9f7bSTejun Heo 11abd54f02STejun Heo #include <linux/sched.h> 12fd7b9f7bSTejun Heo #include <linux/fs.h> 13fd7b9f7bSTejun Heo #include <linux/namei.h> 14fd7b9f7bSTejun Heo #include <linux/idr.h> 15fd7b9f7bSTejun Heo #include <linux/slab.h> 16fd7b9f7bSTejun Heo #include <linux/security.h> 17fd7b9f7bSTejun Heo #include <linux/hash.h> 18fd7b9f7bSTejun Heo 19fd7b9f7bSTejun Heo #include "kernfs-internal.h" 20fd7b9f7bSTejun Heo 21a797bfc3STejun Heo DEFINE_MUTEX(kernfs_mutex); 223eef34adSTejun Heo static DEFINE_SPINLOCK(kernfs_rename_lock); /* kn->parent and ->name */ 233eef34adSTejun Heo static char kernfs_pr_cont_buf[PATH_MAX]; /* protected by rename_lock */ 24fd7b9f7bSTejun Heo 25adc5e8b5STejun Heo #define rb_to_kn(X) rb_entry((X), struct kernfs_node, rb) 26fd7b9f7bSTejun Heo 2781c173cbSTejun Heo static bool kernfs_active(struct kernfs_node *kn) 2881c173cbSTejun Heo { 2981c173cbSTejun Heo lockdep_assert_held(&kernfs_mutex); 3081c173cbSTejun Heo return atomic_read(&kn->active) >= 0; 3181c173cbSTejun Heo } 3281c173cbSTejun Heo 33182fd64bSTejun Heo static bool kernfs_lockdep(struct kernfs_node *kn) 34182fd64bSTejun Heo { 35182fd64bSTejun Heo #ifdef CONFIG_DEBUG_LOCK_ALLOC 36182fd64bSTejun Heo return kn->flags & KERNFS_LOCKDEP; 37182fd64bSTejun Heo #else 38182fd64bSTejun Heo return false; 39182fd64bSTejun Heo #endif 40182fd64bSTejun Heo } 41182fd64bSTejun Heo 423eef34adSTejun Heo static int kernfs_name_locked(struct kernfs_node *kn, char *buf, size_t buflen) 433eef34adSTejun Heo { 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 1409f6df573SAditya Kali common = kernfs_common_ancestor(kn_from, kn_to); 1419f6df573SAditya Kali if (WARN_ON(!common)) 1423abb1d90STejun Heo return -EINVAL; 1439f6df573SAditya Kali 1449f6df573SAditya Kali depth_to = kernfs_depth(common, kn_to); 1459f6df573SAditya Kali depth_from = kernfs_depth(common, kn_from); 1469f6df573SAditya Kali 1479f6df573SAditya Kali if (buf) 1489f6df573SAditya Kali buf[0] = '\0'; 1499f6df573SAditya Kali 1509f6df573SAditya Kali for (i = 0; i < depth_from; i++) 1519f6df573SAditya Kali len += strlcpy(buf + len, parent_str, 1529f6df573SAditya Kali len < buflen ? buflen - len : 0); 1539f6df573SAditya Kali 1549f6df573SAditya Kali /* Calculate how many bytes we need for the rest */ 1553abb1d90STejun Heo for (i = depth_to - 1; i >= 0; i--) { 1563abb1d90STejun Heo for (kn = kn_to, j = 0; j < i; j++) 1573abb1d90STejun Heo kn = kn->parent; 1583abb1d90STejun Heo len += strlcpy(buf + len, "/", 1593abb1d90STejun Heo len < buflen ? buflen - len : 0); 1603abb1d90STejun Heo len += strlcpy(buf + len, kn->name, 1613abb1d90STejun Heo len < buflen ? buflen - len : 0); 1629f6df573SAditya Kali } 1639f6df573SAditya Kali 1643abb1d90STejun Heo return len; 1653eef34adSTejun Heo } 1663eef34adSTejun Heo 1673eef34adSTejun Heo /** 1683eef34adSTejun Heo * kernfs_name - obtain the name of a given node 1693eef34adSTejun Heo * @kn: kernfs_node of interest 1703eef34adSTejun Heo * @buf: buffer to copy @kn's name into 1713eef34adSTejun Heo * @buflen: size of @buf 1723eef34adSTejun Heo * 1733eef34adSTejun Heo * Copies the name of @kn into @buf of @buflen bytes. The behavior is 1743eef34adSTejun Heo * similar to strlcpy(). It returns the length of @kn's name and if @buf 1753eef34adSTejun Heo * isn't long enough, it's filled upto @buflen-1 and nul terminated. 1763eef34adSTejun Heo * 17717627157SKonstantin Khlebnikov * Fills buffer with "(null)" if @kn is NULL. 17817627157SKonstantin Khlebnikov * 1793eef34adSTejun Heo * This function can be called from any context. 1803eef34adSTejun Heo */ 1813eef34adSTejun Heo int kernfs_name(struct kernfs_node *kn, char *buf, size_t buflen) 1823eef34adSTejun Heo { 1833eef34adSTejun Heo unsigned long flags; 1843eef34adSTejun Heo int ret; 1853eef34adSTejun Heo 1863eef34adSTejun Heo spin_lock_irqsave(&kernfs_rename_lock, flags); 1873eef34adSTejun Heo ret = kernfs_name_locked(kn, buf, buflen); 1883eef34adSTejun Heo spin_unlock_irqrestore(&kernfs_rename_lock, flags); 1893eef34adSTejun Heo return ret; 1903eef34adSTejun Heo } 1913eef34adSTejun Heo 1923eef34adSTejun Heo /** 1939f6df573SAditya Kali * kernfs_path_from_node - build path of node @to relative to @from. 1949f6df573SAditya Kali * @from: parent kernfs_node relative to which we need to build the path 1959f6df573SAditya Kali * @to: kernfs_node of interest 1969f6df573SAditya Kali * @buf: buffer to copy @to's path into 1979f6df573SAditya Kali * @buflen: size of @buf 1989f6df573SAditya Kali * 1999f6df573SAditya Kali * Builds @to's path relative to @from in @buf. @from and @to must 2009f6df573SAditya Kali * be on the same kernfs-root. If @from is not parent of @to, then a relative 2019f6df573SAditya Kali * path (which includes '..'s) as needed to reach from @from to @to is 2029f6df573SAditya Kali * returned. 2039f6df573SAditya Kali * 2043abb1d90STejun Heo * Returns the length of the full path. If the full length is equal to or 2053abb1d90STejun Heo * greater than @buflen, @buf contains the truncated path with the trailing 2063abb1d90STejun Heo * '\0'. On error, -errno is returned. 2079f6df573SAditya Kali */ 2089f6df573SAditya Kali int kernfs_path_from_node(struct kernfs_node *to, struct kernfs_node *from, 2099f6df573SAditya Kali char *buf, size_t buflen) 2109f6df573SAditya Kali { 2119f6df573SAditya Kali unsigned long flags; 2129f6df573SAditya Kali int ret; 2139f6df573SAditya Kali 2149f6df573SAditya Kali spin_lock_irqsave(&kernfs_rename_lock, flags); 2159f6df573SAditya Kali ret = kernfs_path_from_node_locked(to, from, buf, buflen); 2169f6df573SAditya Kali spin_unlock_irqrestore(&kernfs_rename_lock, flags); 2179f6df573SAditya Kali return ret; 2189f6df573SAditya Kali } 2199f6df573SAditya Kali EXPORT_SYMBOL_GPL(kernfs_path_from_node); 2209f6df573SAditya Kali 2219f6df573SAditya Kali /** 2223eef34adSTejun Heo * pr_cont_kernfs_name - pr_cont name of a kernfs_node 2233eef34adSTejun Heo * @kn: kernfs_node of interest 2243eef34adSTejun Heo * 2253eef34adSTejun Heo * This function can be called from any context. 2263eef34adSTejun Heo */ 2273eef34adSTejun Heo void pr_cont_kernfs_name(struct kernfs_node *kn) 2283eef34adSTejun Heo { 2293eef34adSTejun Heo unsigned long flags; 2303eef34adSTejun Heo 2313eef34adSTejun Heo spin_lock_irqsave(&kernfs_rename_lock, flags); 2323eef34adSTejun Heo 2333eef34adSTejun Heo kernfs_name_locked(kn, kernfs_pr_cont_buf, sizeof(kernfs_pr_cont_buf)); 2343eef34adSTejun Heo pr_cont("%s", kernfs_pr_cont_buf); 2353eef34adSTejun Heo 2363eef34adSTejun Heo spin_unlock_irqrestore(&kernfs_rename_lock, flags); 2373eef34adSTejun Heo } 2383eef34adSTejun Heo 2393eef34adSTejun Heo /** 2403eef34adSTejun Heo * pr_cont_kernfs_path - pr_cont path of a kernfs_node 2413eef34adSTejun Heo * @kn: kernfs_node of interest 2423eef34adSTejun Heo * 2433eef34adSTejun Heo * This function can be called from any context. 2443eef34adSTejun Heo */ 2453eef34adSTejun Heo void pr_cont_kernfs_path(struct kernfs_node *kn) 2463eef34adSTejun Heo { 2473eef34adSTejun Heo unsigned long flags; 2489f6df573SAditya Kali int sz; 2493eef34adSTejun Heo 2503eef34adSTejun Heo spin_lock_irqsave(&kernfs_rename_lock, flags); 2513eef34adSTejun Heo 2529f6df573SAditya Kali sz = kernfs_path_from_node_locked(kn, NULL, kernfs_pr_cont_buf, 2533eef34adSTejun Heo sizeof(kernfs_pr_cont_buf)); 2549f6df573SAditya Kali if (sz < 0) { 2559f6df573SAditya Kali pr_cont("(error)"); 2569f6df573SAditya Kali goto out; 2579f6df573SAditya Kali } 2583eef34adSTejun Heo 2599f6df573SAditya Kali if (sz >= sizeof(kernfs_pr_cont_buf)) { 2609f6df573SAditya Kali pr_cont("(name too long)"); 2619f6df573SAditya Kali goto out; 2629f6df573SAditya Kali } 2639f6df573SAditya Kali 2649f6df573SAditya Kali pr_cont("%s", kernfs_pr_cont_buf); 2659f6df573SAditya Kali 2669f6df573SAditya Kali out: 2673eef34adSTejun Heo spin_unlock_irqrestore(&kernfs_rename_lock, flags); 2683eef34adSTejun Heo } 2693eef34adSTejun Heo 2703eef34adSTejun Heo /** 2713eef34adSTejun Heo * kernfs_get_parent - determine the parent node and pin it 2723eef34adSTejun Heo * @kn: kernfs_node of interest 2733eef34adSTejun Heo * 2743eef34adSTejun Heo * Determines @kn's parent, pins and returns it. This function can be 2753eef34adSTejun Heo * called from any context. 2763eef34adSTejun Heo */ 2773eef34adSTejun Heo struct kernfs_node *kernfs_get_parent(struct kernfs_node *kn) 2783eef34adSTejun Heo { 2793eef34adSTejun Heo struct kernfs_node *parent; 2803eef34adSTejun Heo unsigned long flags; 2813eef34adSTejun Heo 2823eef34adSTejun Heo spin_lock_irqsave(&kernfs_rename_lock, flags); 2833eef34adSTejun Heo parent = kn->parent; 2843eef34adSTejun Heo kernfs_get(parent); 2853eef34adSTejun Heo spin_unlock_irqrestore(&kernfs_rename_lock, flags); 2863eef34adSTejun Heo 2873eef34adSTejun Heo return parent; 2883eef34adSTejun Heo } 2893eef34adSTejun Heo 290fd7b9f7bSTejun Heo /** 291c637b8acSTejun Heo * kernfs_name_hash 292fd7b9f7bSTejun Heo * @name: Null terminated string to hash 293fd7b9f7bSTejun Heo * @ns: Namespace tag to hash 294fd7b9f7bSTejun Heo * 295fd7b9f7bSTejun Heo * Returns 31 bit hash of ns + name (so it fits in an off_t ) 296fd7b9f7bSTejun Heo */ 297c637b8acSTejun Heo static unsigned int kernfs_name_hash(const char *name, const void *ns) 298fd7b9f7bSTejun Heo { 2998387ff25SLinus Torvalds unsigned long hash = init_name_hash(ns); 300fd7b9f7bSTejun Heo unsigned int len = strlen(name); 301fd7b9f7bSTejun Heo while (len--) 302fd7b9f7bSTejun Heo hash = partial_name_hash(*name++, hash); 3038387ff25SLinus Torvalds hash = end_name_hash(hash); 304fd7b9f7bSTejun Heo hash &= 0x7fffffffU; 305fd7b9f7bSTejun Heo /* Reserve hash numbers 0, 1 and INT_MAX for magic directory entries */ 30688391d49SRichard Cochran if (hash < 2) 307fd7b9f7bSTejun Heo hash += 2; 308fd7b9f7bSTejun Heo if (hash >= INT_MAX) 309fd7b9f7bSTejun Heo hash = INT_MAX - 1; 310fd7b9f7bSTejun Heo return hash; 311fd7b9f7bSTejun Heo } 312fd7b9f7bSTejun Heo 313c637b8acSTejun Heo static int kernfs_name_compare(unsigned int hash, const char *name, 314324a56e1STejun Heo const void *ns, const struct kernfs_node *kn) 315fd7b9f7bSTejun Heo { 31672392ed0SRasmus Villemoes if (hash < kn->hash) 31772392ed0SRasmus Villemoes return -1; 31872392ed0SRasmus Villemoes if (hash > kn->hash) 31972392ed0SRasmus Villemoes return 1; 32072392ed0SRasmus Villemoes if (ns < kn->ns) 32172392ed0SRasmus Villemoes return -1; 32272392ed0SRasmus Villemoes if (ns > kn->ns) 32372392ed0SRasmus Villemoes return 1; 324adc5e8b5STejun Heo return strcmp(name, kn->name); 325fd7b9f7bSTejun Heo } 326fd7b9f7bSTejun Heo 327c637b8acSTejun Heo static int kernfs_sd_compare(const struct kernfs_node *left, 328324a56e1STejun Heo const struct kernfs_node *right) 329fd7b9f7bSTejun Heo { 330c637b8acSTejun Heo return kernfs_name_compare(left->hash, left->name, left->ns, right); 331fd7b9f7bSTejun Heo } 332fd7b9f7bSTejun Heo 333fd7b9f7bSTejun Heo /** 334c637b8acSTejun Heo * kernfs_link_sibling - link kernfs_node into sibling rbtree 335324a56e1STejun Heo * @kn: kernfs_node of interest 336fd7b9f7bSTejun Heo * 337324a56e1STejun Heo * Link @kn into its sibling rbtree which starts from 338adc5e8b5STejun Heo * @kn->parent->dir.children. 339fd7b9f7bSTejun Heo * 340fd7b9f7bSTejun Heo * Locking: 341a797bfc3STejun Heo * mutex_lock(kernfs_mutex) 342fd7b9f7bSTejun Heo * 343fd7b9f7bSTejun Heo * RETURNS: 344fd7b9f7bSTejun Heo * 0 on susccess -EEXIST on failure. 345fd7b9f7bSTejun Heo */ 346c637b8acSTejun Heo static int kernfs_link_sibling(struct kernfs_node *kn) 347fd7b9f7bSTejun Heo { 348adc5e8b5STejun Heo struct rb_node **node = &kn->parent->dir.children.rb_node; 349fd7b9f7bSTejun Heo struct rb_node *parent = NULL; 350fd7b9f7bSTejun Heo 351fd7b9f7bSTejun Heo while (*node) { 352324a56e1STejun Heo struct kernfs_node *pos; 353fd7b9f7bSTejun Heo int result; 354fd7b9f7bSTejun Heo 355324a56e1STejun Heo pos = rb_to_kn(*node); 356fd7b9f7bSTejun Heo parent = *node; 357c637b8acSTejun Heo result = kernfs_sd_compare(kn, pos); 358fd7b9f7bSTejun Heo if (result < 0) 359adc5e8b5STejun Heo node = &pos->rb.rb_left; 360fd7b9f7bSTejun Heo else if (result > 0) 361adc5e8b5STejun Heo node = &pos->rb.rb_right; 362fd7b9f7bSTejun Heo else 363fd7b9f7bSTejun Heo return -EEXIST; 364fd7b9f7bSTejun Heo } 365c1befb88SJianyu Zhan 366fd7b9f7bSTejun Heo /* add new node and rebalance the tree */ 367adc5e8b5STejun Heo rb_link_node(&kn->rb, parent, node); 368adc5e8b5STejun Heo rb_insert_color(&kn->rb, &kn->parent->dir.children); 369c1befb88SJianyu Zhan 370c1befb88SJianyu Zhan /* successfully added, account subdir number */ 371c1befb88SJianyu Zhan if (kernfs_type(kn) == KERNFS_DIR) 372c1befb88SJianyu Zhan kn->parent->dir.subdirs++; 373c1befb88SJianyu Zhan 374fd7b9f7bSTejun Heo return 0; 375fd7b9f7bSTejun Heo } 376fd7b9f7bSTejun Heo 377fd7b9f7bSTejun Heo /** 378c637b8acSTejun Heo * kernfs_unlink_sibling - unlink kernfs_node from sibling rbtree 379324a56e1STejun Heo * @kn: kernfs_node of interest 380fd7b9f7bSTejun Heo * 38135beab06STejun Heo * Try to unlink @kn from its sibling rbtree which starts from 38235beab06STejun Heo * kn->parent->dir.children. Returns %true if @kn was actually 38335beab06STejun Heo * removed, %false if @kn wasn't on the rbtree. 384fd7b9f7bSTejun Heo * 385fd7b9f7bSTejun Heo * Locking: 386a797bfc3STejun Heo * mutex_lock(kernfs_mutex) 387fd7b9f7bSTejun Heo */ 38835beab06STejun Heo static bool kernfs_unlink_sibling(struct kernfs_node *kn) 389fd7b9f7bSTejun Heo { 39035beab06STejun Heo if (RB_EMPTY_NODE(&kn->rb)) 39135beab06STejun Heo return false; 39235beab06STejun Heo 393df23fc39STejun Heo if (kernfs_type(kn) == KERNFS_DIR) 394adc5e8b5STejun Heo kn->parent->dir.subdirs--; 395fd7b9f7bSTejun Heo 396adc5e8b5STejun Heo rb_erase(&kn->rb, &kn->parent->dir.children); 39735beab06STejun Heo RB_CLEAR_NODE(&kn->rb); 39835beab06STejun Heo return true; 399fd7b9f7bSTejun Heo } 400fd7b9f7bSTejun Heo 401fd7b9f7bSTejun Heo /** 402c637b8acSTejun Heo * kernfs_get_active - get an active reference to kernfs_node 403324a56e1STejun Heo * @kn: kernfs_node to get an active reference to 404fd7b9f7bSTejun Heo * 405324a56e1STejun Heo * Get an active reference of @kn. This function is noop if @kn 406fd7b9f7bSTejun Heo * is NULL. 407fd7b9f7bSTejun Heo * 408fd7b9f7bSTejun Heo * RETURNS: 409324a56e1STejun Heo * Pointer to @kn on success, NULL on failure. 410fd7b9f7bSTejun Heo */ 411c637b8acSTejun Heo struct kernfs_node *kernfs_get_active(struct kernfs_node *kn) 412fd7b9f7bSTejun Heo { 413324a56e1STejun Heo if (unlikely(!kn)) 414fd7b9f7bSTejun Heo return NULL; 415fd7b9f7bSTejun Heo 416f4b3e631SGreg Kroah-Hartman if (!atomic_inc_unless_negative(&kn->active)) 417f4b3e631SGreg Kroah-Hartman return NULL; 418f4b3e631SGreg Kroah-Hartman 419182fd64bSTejun Heo if (kernfs_lockdep(kn)) 420324a56e1STejun Heo rwsem_acquire_read(&kn->dep_map, 0, 1, _RET_IP_); 421324a56e1STejun Heo return kn; 422fd7b9f7bSTejun Heo } 423fd7b9f7bSTejun Heo 424fd7b9f7bSTejun Heo /** 425c637b8acSTejun Heo * kernfs_put_active - put an active reference to kernfs_node 426324a56e1STejun Heo * @kn: kernfs_node to put an active reference to 427fd7b9f7bSTejun Heo * 428324a56e1STejun Heo * Put an active reference to @kn. This function is noop if @kn 429fd7b9f7bSTejun Heo * is NULL. 430fd7b9f7bSTejun Heo */ 431c637b8acSTejun Heo void kernfs_put_active(struct kernfs_node *kn) 432fd7b9f7bSTejun Heo { 433abd54f02STejun Heo struct kernfs_root *root = kernfs_root(kn); 434fd7b9f7bSTejun Heo int v; 435fd7b9f7bSTejun Heo 436324a56e1STejun Heo if (unlikely(!kn)) 437fd7b9f7bSTejun Heo return; 438fd7b9f7bSTejun Heo 439182fd64bSTejun Heo if (kernfs_lockdep(kn)) 440324a56e1STejun Heo rwsem_release(&kn->dep_map, 1, _RET_IP_); 441adc5e8b5STejun Heo v = atomic_dec_return(&kn->active); 442df23fc39STejun Heo if (likely(v != KN_DEACTIVATED_BIAS)) 443fd7b9f7bSTejun Heo return; 444fd7b9f7bSTejun Heo 445abd54f02STejun Heo wake_up_all(&root->deactivate_waitq); 446fd7b9f7bSTejun Heo } 447fd7b9f7bSTejun Heo 448fd7b9f7bSTejun Heo /** 44981c173cbSTejun Heo * kernfs_drain - drain kernfs_node 45081c173cbSTejun Heo * @kn: kernfs_node to drain 451fd7b9f7bSTejun Heo * 45281c173cbSTejun Heo * Drain existing usages and nuke all existing mmaps of @kn. Mutiple 45381c173cbSTejun Heo * removers may invoke this function concurrently on @kn and all will 45481c173cbSTejun Heo * return after draining is complete. 455fd7b9f7bSTejun Heo */ 45681c173cbSTejun Heo static void kernfs_drain(struct kernfs_node *kn) 45735beab06STejun Heo __releases(&kernfs_mutex) __acquires(&kernfs_mutex) 458fd7b9f7bSTejun Heo { 459abd54f02STejun Heo struct kernfs_root *root = kernfs_root(kn); 460fd7b9f7bSTejun Heo 46135beab06STejun Heo lockdep_assert_held(&kernfs_mutex); 46281c173cbSTejun Heo WARN_ON_ONCE(kernfs_active(kn)); 463abd54f02STejun Heo 46435beab06STejun Heo mutex_unlock(&kernfs_mutex); 465abd54f02STejun Heo 466182fd64bSTejun Heo if (kernfs_lockdep(kn)) { 46735beab06STejun Heo rwsem_acquire(&kn->dep_map, 0, 0, _RET_IP_); 46835beab06STejun Heo if (atomic_read(&kn->active) != KN_DEACTIVATED_BIAS) 46935beab06STejun Heo lock_contended(&kn->dep_map, _RET_IP_); 47035beab06STejun Heo } 47135beab06STejun Heo 47235beab06STejun Heo /* but everyone should wait for draining */ 473abd54f02STejun Heo wait_event(root->deactivate_waitq, 474abd54f02STejun Heo atomic_read(&kn->active) == KN_DEACTIVATED_BIAS); 475fd7b9f7bSTejun Heo 476182fd64bSTejun Heo if (kernfs_lockdep(kn)) { 477324a56e1STejun Heo lock_acquired(&kn->dep_map, _RET_IP_); 478324a56e1STejun Heo rwsem_release(&kn->dep_map, 1, _RET_IP_); 479fd7b9f7bSTejun Heo } 48035beab06STejun Heo 481ccf02aafSTejun Heo kernfs_unmap_bin_file(kn); 482ccf02aafSTejun Heo 48335beab06STejun Heo mutex_lock(&kernfs_mutex); 484a6607930STejun Heo } 485fd7b9f7bSTejun Heo 486fd7b9f7bSTejun Heo /** 487324a56e1STejun Heo * kernfs_get - get a reference count on a kernfs_node 488324a56e1STejun Heo * @kn: the target kernfs_node 489fd7b9f7bSTejun Heo */ 490324a56e1STejun Heo void kernfs_get(struct kernfs_node *kn) 491fd7b9f7bSTejun Heo { 492324a56e1STejun Heo if (kn) { 493adc5e8b5STejun Heo WARN_ON(!atomic_read(&kn->count)); 494adc5e8b5STejun Heo atomic_inc(&kn->count); 495fd7b9f7bSTejun Heo } 496fd7b9f7bSTejun Heo } 497fd7b9f7bSTejun Heo EXPORT_SYMBOL_GPL(kernfs_get); 498fd7b9f7bSTejun Heo 499fd7b9f7bSTejun Heo /** 500324a56e1STejun Heo * kernfs_put - put a reference count on a kernfs_node 501324a56e1STejun Heo * @kn: the target kernfs_node 502fd7b9f7bSTejun Heo * 503324a56e1STejun Heo * Put a reference count of @kn and destroy it if it reached zero. 504fd7b9f7bSTejun Heo */ 505324a56e1STejun Heo void kernfs_put(struct kernfs_node *kn) 506fd7b9f7bSTejun Heo { 507324a56e1STejun Heo struct kernfs_node *parent; 508ba7443bcSTejun Heo struct kernfs_root *root; 509fd7b9f7bSTejun Heo 510adc5e8b5STejun Heo if (!kn || !atomic_dec_and_test(&kn->count)) 511fd7b9f7bSTejun Heo return; 512324a56e1STejun Heo root = kernfs_root(kn); 513fd7b9f7bSTejun Heo repeat: 51481c173cbSTejun Heo /* 51581c173cbSTejun Heo * Moving/renaming is always done while holding reference. 516adc5e8b5STejun Heo * kn->parent won't change beneath us. 517fd7b9f7bSTejun Heo */ 518adc5e8b5STejun Heo parent = kn->parent; 519fd7b9f7bSTejun Heo 52081c173cbSTejun Heo WARN_ONCE(atomic_read(&kn->active) != KN_DEACTIVATED_BIAS, 52181c173cbSTejun Heo "kernfs_put: %s/%s: released with incorrect active_ref %d\n", 52281c173cbSTejun Heo parent ? parent->name : "", kn->name, atomic_read(&kn->active)); 523fd7b9f7bSTejun Heo 524df23fc39STejun Heo if (kernfs_type(kn) == KERNFS_LINK) 525adc5e8b5STejun Heo kernfs_put(kn->symlink.target_kn); 526dfeb0750STejun Heo 52775287a67SAndrzej Hajda kfree_const(kn->name); 528dfeb0750STejun Heo 529adc5e8b5STejun Heo if (kn->iattr) { 530adc5e8b5STejun Heo if (kn->iattr->ia_secdata) 531adc5e8b5STejun Heo security_release_secctx(kn->iattr->ia_secdata, 532adc5e8b5STejun Heo kn->iattr->ia_secdata_len); 533adc5e8b5STejun Heo simple_xattrs_free(&kn->iattr->xattrs); 5342322392bSTejun Heo } 535adc5e8b5STejun Heo kfree(kn->iattr); 536adc5e8b5STejun Heo ida_simple_remove(&root->ino_ida, kn->ino); 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 */ 545bc755553STejun Heo ida_destroy(&root->ino_ida); 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 562324a56e1STejun Heo kn = dentry->d_fsdata; 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? */ 570adc5e8b5STejun Heo if (dentry->d_parent->d_fsdata != 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 590c637b8acSTejun Heo static void kernfs_dop_release(struct dentry *dentry) 591fd7b9f7bSTejun Heo { 592fd7b9f7bSTejun Heo kernfs_put(dentry->d_fsdata); 593fd7b9f7bSTejun Heo } 594fd7b9f7bSTejun Heo 595a797bfc3STejun Heo const struct dentry_operations kernfs_dops = { 596c637b8acSTejun Heo .d_revalidate = kernfs_dop_revalidate, 597c637b8acSTejun Heo .d_release = kernfs_dop_release, 598fd7b9f7bSTejun Heo }; 599fd7b9f7bSTejun Heo 6000c23b225STejun Heo /** 6010c23b225STejun Heo * kernfs_node_from_dentry - determine kernfs_node associated with a dentry 6020c23b225STejun Heo * @dentry: the dentry in question 6030c23b225STejun Heo * 6040c23b225STejun Heo * Return the kernfs_node associated with @dentry. If @dentry is not a 6050c23b225STejun Heo * kernfs one, %NULL is returned. 6060c23b225STejun Heo * 6070c23b225STejun Heo * While the returned kernfs_node will stay accessible as long as @dentry 6080c23b225STejun Heo * is accessible, the returned node can be in any state and the caller is 6090c23b225STejun Heo * fully responsible for determining what's accessible. 6100c23b225STejun Heo */ 6110c23b225STejun Heo struct kernfs_node *kernfs_node_from_dentry(struct dentry *dentry) 6120c23b225STejun Heo { 613f41c5934SLi Zefan if (dentry->d_sb->s_op == &kernfs_sops) 6140c23b225STejun Heo return dentry->d_fsdata; 6150c23b225STejun Heo return NULL; 6160c23b225STejun Heo } 6170c23b225STejun Heo 618db4aad20STejun Heo static struct kernfs_node *__kernfs_new_node(struct kernfs_root *root, 619db4aad20STejun Heo const char *name, umode_t mode, 620db4aad20STejun Heo unsigned flags) 621fd7b9f7bSTejun Heo { 622324a56e1STejun Heo struct kernfs_node *kn; 623bc755553STejun Heo int ret; 624fd7b9f7bSTejun Heo 625dfeb0750STejun Heo name = kstrdup_const(name, GFP_KERNEL); 626fd7b9f7bSTejun Heo if (!name) 627fd7b9f7bSTejun Heo return NULL; 628fd7b9f7bSTejun Heo 629a797bfc3STejun Heo kn = kmem_cache_zalloc(kernfs_node_cache, GFP_KERNEL); 630324a56e1STejun Heo if (!kn) 631fd7b9f7bSTejun Heo goto err_out1; 632fd7b9f7bSTejun Heo 633b2a209ffSVladimir Davydov ret = ida_simple_get(&root->ino_ida, 1, 0, GFP_KERNEL); 634bc755553STejun Heo if (ret < 0) 635fd7b9f7bSTejun Heo goto err_out2; 636adc5e8b5STejun Heo kn->ino = ret; 637fd7b9f7bSTejun Heo 638adc5e8b5STejun Heo atomic_set(&kn->count, 1); 63981c173cbSTejun Heo atomic_set(&kn->active, KN_DEACTIVATED_BIAS); 64035beab06STejun Heo RB_CLEAR_NODE(&kn->rb); 641fd7b9f7bSTejun Heo 642adc5e8b5STejun Heo kn->name = name; 643adc5e8b5STejun Heo kn->mode = mode; 64481c173cbSTejun Heo kn->flags = flags; 645fd7b9f7bSTejun Heo 646324a56e1STejun Heo return kn; 647fd7b9f7bSTejun Heo 648fd7b9f7bSTejun Heo err_out2: 649a797bfc3STejun Heo kmem_cache_free(kernfs_node_cache, kn); 650fd7b9f7bSTejun Heo err_out1: 651dfeb0750STejun Heo kfree_const(name); 652fd7b9f7bSTejun Heo return NULL; 653fd7b9f7bSTejun Heo } 654fd7b9f7bSTejun Heo 655db4aad20STejun Heo struct kernfs_node *kernfs_new_node(struct kernfs_node *parent, 656db4aad20STejun Heo const char *name, umode_t mode, 657db4aad20STejun Heo unsigned flags) 658db4aad20STejun Heo { 659db4aad20STejun Heo struct kernfs_node *kn; 660db4aad20STejun Heo 661db4aad20STejun Heo kn = __kernfs_new_node(kernfs_root(parent), name, mode, flags); 662db4aad20STejun Heo if (kn) { 663db4aad20STejun Heo kernfs_get(parent); 664db4aad20STejun Heo kn->parent = parent; 665db4aad20STejun Heo } 666db4aad20STejun Heo return kn; 667db4aad20STejun Heo } 668db4aad20STejun Heo 669fd7b9f7bSTejun Heo /** 670c637b8acSTejun Heo * kernfs_add_one - add kernfs_node to parent without warning 671324a56e1STejun Heo * @kn: kernfs_node to be added 672fd7b9f7bSTejun Heo * 673db4aad20STejun Heo * The caller must already have initialized @kn->parent. This 674db4aad20STejun Heo * function increments nlink of the parent's inode if @kn is a 675db4aad20STejun Heo * directory and link into the children list of the parent. 676fd7b9f7bSTejun Heo * 677fd7b9f7bSTejun Heo * RETURNS: 678fd7b9f7bSTejun Heo * 0 on success, -EEXIST if entry with the given name already 679fd7b9f7bSTejun Heo * exists. 680fd7b9f7bSTejun Heo */ 681988cd7afSTejun Heo int kernfs_add_one(struct kernfs_node *kn) 682fd7b9f7bSTejun Heo { 683db4aad20STejun Heo struct kernfs_node *parent = kn->parent; 684c525aaddSTejun Heo struct kernfs_iattrs *ps_iattr; 685988cd7afSTejun Heo bool has_ns; 686fd7b9f7bSTejun Heo int ret; 687fd7b9f7bSTejun Heo 688988cd7afSTejun Heo mutex_lock(&kernfs_mutex); 689988cd7afSTejun Heo 690988cd7afSTejun Heo ret = -EINVAL; 691988cd7afSTejun Heo has_ns = kernfs_ns_enabled(parent); 692988cd7afSTejun Heo if (WARN(has_ns != (bool)kn->ns, KERN_WARNING "kernfs: ns %s in '%s' for '%s'\n", 693988cd7afSTejun Heo has_ns ? "required" : "invalid", parent->name, kn->name)) 694988cd7afSTejun Heo goto out_unlock; 695fd7b9f7bSTejun Heo 696df23fc39STejun Heo if (kernfs_type(parent) != KERNFS_DIR) 697988cd7afSTejun Heo goto out_unlock; 698fd7b9f7bSTejun Heo 699988cd7afSTejun Heo ret = -ENOENT; 700ea015218SEric W. Biederman if (parent->flags & KERNFS_EMPTY_DIR) 701ea015218SEric W. Biederman goto out_unlock; 702ea015218SEric W. Biederman 703d35258efSTejun Heo if ((parent->flags & KERNFS_ACTIVATED) && !kernfs_active(parent)) 704988cd7afSTejun Heo goto out_unlock; 705798c75a0SGreg Kroah-Hartman 706c637b8acSTejun Heo kn->hash = kernfs_name_hash(kn->name, kn->ns); 707fd7b9f7bSTejun Heo 708c637b8acSTejun Heo ret = kernfs_link_sibling(kn); 709fd7b9f7bSTejun Heo if (ret) 710988cd7afSTejun Heo goto out_unlock; 711fd7b9f7bSTejun Heo 712fd7b9f7bSTejun Heo /* Update timestamps on the parent */ 713adc5e8b5STejun Heo ps_iattr = parent->iattr; 714fd7b9f7bSTejun Heo if (ps_iattr) { 715fd7b9f7bSTejun Heo struct iattr *ps_iattrs = &ps_iattr->ia_iattr; 7163a3a5fecSDeepa Dinamani ktime_get_real_ts(&ps_iattrs->ia_ctime); 7173a3a5fecSDeepa Dinamani ps_iattrs->ia_mtime = ps_iattrs->ia_ctime; 718fd7b9f7bSTejun Heo } 719fd7b9f7bSTejun Heo 720d35258efSTejun Heo mutex_unlock(&kernfs_mutex); 721d35258efSTejun Heo 722d35258efSTejun Heo /* 723d35258efSTejun Heo * Activate the new node unless CREATE_DEACTIVATED is requested. 724d35258efSTejun Heo * If not activated here, the kernfs user is responsible for 725d35258efSTejun Heo * activating the node with kernfs_activate(). A node which hasn't 726d35258efSTejun Heo * been activated is not visible to userland and its removal won't 727d35258efSTejun Heo * trigger deactivation. 728d35258efSTejun Heo */ 729d35258efSTejun Heo if (!(kernfs_root(kn)->flags & KERNFS_ROOT_CREATE_DEACTIVATED)) 730d35258efSTejun Heo kernfs_activate(kn); 731d35258efSTejun Heo return 0; 732d35258efSTejun Heo 733988cd7afSTejun Heo out_unlock: 734a797bfc3STejun Heo mutex_unlock(&kernfs_mutex); 735988cd7afSTejun Heo return ret; 736fd7b9f7bSTejun Heo } 737fd7b9f7bSTejun Heo 738fd7b9f7bSTejun Heo /** 739324a56e1STejun Heo * kernfs_find_ns - find kernfs_node with the given name 740324a56e1STejun Heo * @parent: kernfs_node to search under 741fd7b9f7bSTejun Heo * @name: name to look for 742fd7b9f7bSTejun Heo * @ns: the namespace tag to use 743fd7b9f7bSTejun Heo * 744324a56e1STejun Heo * Look for kernfs_node with name @name under @parent. Returns pointer to 745324a56e1STejun Heo * the found kernfs_node on success, %NULL on failure. 746fd7b9f7bSTejun Heo */ 747324a56e1STejun Heo static struct kernfs_node *kernfs_find_ns(struct kernfs_node *parent, 748fd7b9f7bSTejun Heo const unsigned char *name, 749fd7b9f7bSTejun Heo const void *ns) 750fd7b9f7bSTejun Heo { 751adc5e8b5STejun Heo struct rb_node *node = parent->dir.children.rb_node; 752ac9bba03STejun Heo bool has_ns = kernfs_ns_enabled(parent); 753fd7b9f7bSTejun Heo unsigned int hash; 754fd7b9f7bSTejun Heo 755a797bfc3STejun Heo lockdep_assert_held(&kernfs_mutex); 756fd7b9f7bSTejun Heo 757fd7b9f7bSTejun Heo if (has_ns != (bool)ns) { 758c637b8acSTejun Heo WARN(1, KERN_WARNING "kernfs: ns %s in '%s' for '%s'\n", 759adc5e8b5STejun Heo has_ns ? "required" : "invalid", parent->name, name); 760fd7b9f7bSTejun Heo return NULL; 761fd7b9f7bSTejun Heo } 762fd7b9f7bSTejun Heo 763c637b8acSTejun Heo hash = kernfs_name_hash(name, ns); 764fd7b9f7bSTejun Heo while (node) { 765324a56e1STejun Heo struct kernfs_node *kn; 766fd7b9f7bSTejun Heo int result; 767fd7b9f7bSTejun Heo 768324a56e1STejun Heo kn = rb_to_kn(node); 769c637b8acSTejun Heo result = kernfs_name_compare(hash, name, ns, kn); 770fd7b9f7bSTejun Heo if (result < 0) 771fd7b9f7bSTejun Heo node = node->rb_left; 772fd7b9f7bSTejun Heo else if (result > 0) 773fd7b9f7bSTejun Heo node = node->rb_right; 774fd7b9f7bSTejun Heo else 775324a56e1STejun Heo return kn; 776fd7b9f7bSTejun Heo } 777fd7b9f7bSTejun Heo return NULL; 778fd7b9f7bSTejun Heo } 779fd7b9f7bSTejun Heo 780bd96f76aSTejun Heo static struct kernfs_node *kernfs_walk_ns(struct kernfs_node *parent, 781bd96f76aSTejun Heo const unsigned char *path, 782bd96f76aSTejun Heo const void *ns) 783bd96f76aSTejun Heo { 784e56ed358STejun Heo size_t len; 785e56ed358STejun Heo char *p, *name; 786bd96f76aSTejun Heo 787bd96f76aSTejun Heo lockdep_assert_held(&kernfs_mutex); 788bd96f76aSTejun Heo 789e56ed358STejun Heo /* grab kernfs_rename_lock to piggy back on kernfs_pr_cont_buf */ 790e56ed358STejun Heo spin_lock_irq(&kernfs_rename_lock); 791e56ed358STejun Heo 792e56ed358STejun Heo len = strlcpy(kernfs_pr_cont_buf, path, sizeof(kernfs_pr_cont_buf)); 793e56ed358STejun Heo 794e56ed358STejun Heo if (len >= sizeof(kernfs_pr_cont_buf)) { 795e56ed358STejun Heo spin_unlock_irq(&kernfs_rename_lock); 796bd96f76aSTejun Heo return NULL; 797e56ed358STejun Heo } 798e56ed358STejun Heo 799e56ed358STejun Heo p = kernfs_pr_cont_buf; 800bd96f76aSTejun Heo 801bd96f76aSTejun Heo while ((name = strsep(&p, "/")) && parent) { 802bd96f76aSTejun Heo if (*name == '\0') 803bd96f76aSTejun Heo continue; 804bd96f76aSTejun Heo parent = kernfs_find_ns(parent, name, ns); 805bd96f76aSTejun Heo } 806bd96f76aSTejun Heo 807e56ed358STejun Heo spin_unlock_irq(&kernfs_rename_lock); 808e56ed358STejun Heo 809bd96f76aSTejun Heo return parent; 810bd96f76aSTejun Heo } 811bd96f76aSTejun Heo 812fd7b9f7bSTejun Heo /** 813324a56e1STejun Heo * kernfs_find_and_get_ns - find and get kernfs_node with the given name 814324a56e1STejun Heo * @parent: kernfs_node to search under 815fd7b9f7bSTejun Heo * @name: name to look for 816fd7b9f7bSTejun Heo * @ns: the namespace tag to use 817fd7b9f7bSTejun Heo * 818324a56e1STejun Heo * Look for kernfs_node with name @name under @parent and get a reference 819fd7b9f7bSTejun Heo * if found. This function may sleep and returns pointer to the found 820324a56e1STejun Heo * kernfs_node on success, %NULL on failure. 821fd7b9f7bSTejun Heo */ 822324a56e1STejun Heo struct kernfs_node *kernfs_find_and_get_ns(struct kernfs_node *parent, 823fd7b9f7bSTejun Heo const char *name, const void *ns) 824fd7b9f7bSTejun Heo { 825324a56e1STejun Heo struct kernfs_node *kn; 826fd7b9f7bSTejun Heo 827a797bfc3STejun Heo mutex_lock(&kernfs_mutex); 828324a56e1STejun Heo kn = kernfs_find_ns(parent, name, ns); 829324a56e1STejun Heo kernfs_get(kn); 830a797bfc3STejun Heo mutex_unlock(&kernfs_mutex); 831fd7b9f7bSTejun Heo 832324a56e1STejun Heo return kn; 833fd7b9f7bSTejun Heo } 834fd7b9f7bSTejun Heo EXPORT_SYMBOL_GPL(kernfs_find_and_get_ns); 835fd7b9f7bSTejun Heo 836fd7b9f7bSTejun Heo /** 837bd96f76aSTejun Heo * kernfs_walk_and_get_ns - find and get kernfs_node with the given path 838bd96f76aSTejun Heo * @parent: kernfs_node to search under 839bd96f76aSTejun Heo * @path: path to look for 840bd96f76aSTejun Heo * @ns: the namespace tag to use 841bd96f76aSTejun Heo * 842bd96f76aSTejun Heo * Look for kernfs_node with path @path under @parent and get a reference 843bd96f76aSTejun Heo * if found. This function may sleep and returns pointer to the found 844bd96f76aSTejun Heo * kernfs_node on success, %NULL on failure. 845bd96f76aSTejun Heo */ 846bd96f76aSTejun Heo struct kernfs_node *kernfs_walk_and_get_ns(struct kernfs_node *parent, 847bd96f76aSTejun Heo const char *path, const void *ns) 848bd96f76aSTejun Heo { 849bd96f76aSTejun Heo struct kernfs_node *kn; 850bd96f76aSTejun Heo 851bd96f76aSTejun Heo mutex_lock(&kernfs_mutex); 852bd96f76aSTejun Heo kn = kernfs_walk_ns(parent, path, ns); 853bd96f76aSTejun Heo kernfs_get(kn); 854bd96f76aSTejun Heo mutex_unlock(&kernfs_mutex); 855bd96f76aSTejun Heo 856bd96f76aSTejun Heo return kn; 857bd96f76aSTejun Heo } 858bd96f76aSTejun Heo 859bd96f76aSTejun Heo /** 860ba7443bcSTejun Heo * kernfs_create_root - create a new kernfs hierarchy 86190c07c89STejun Heo * @scops: optional syscall operations for the hierarchy 862d35258efSTejun Heo * @flags: KERNFS_ROOT_* flags 863ba7443bcSTejun Heo * @priv: opaque data associated with the new directory 864ba7443bcSTejun Heo * 865ba7443bcSTejun Heo * Returns the root of the new hierarchy on success, ERR_PTR() value on 866ba7443bcSTejun Heo * failure. 867ba7443bcSTejun Heo */ 86890c07c89STejun Heo struct kernfs_root *kernfs_create_root(struct kernfs_syscall_ops *scops, 869d35258efSTejun Heo unsigned int flags, void *priv) 870ba7443bcSTejun Heo { 871ba7443bcSTejun Heo struct kernfs_root *root; 872324a56e1STejun Heo struct kernfs_node *kn; 873ba7443bcSTejun Heo 874ba7443bcSTejun Heo root = kzalloc(sizeof(*root), GFP_KERNEL); 875ba7443bcSTejun Heo if (!root) 876ba7443bcSTejun Heo return ERR_PTR(-ENOMEM); 877ba7443bcSTejun Heo 878bc755553STejun Heo ida_init(&root->ino_ida); 8797d568a83STejun Heo INIT_LIST_HEAD(&root->supers); 880bc755553STejun Heo 881db4aad20STejun Heo kn = __kernfs_new_node(root, "", S_IFDIR | S_IRUGO | S_IXUGO, 882db4aad20STejun Heo KERNFS_DIR); 883324a56e1STejun Heo if (!kn) { 884bc755553STejun Heo ida_destroy(&root->ino_ida); 885ba7443bcSTejun Heo kfree(root); 886ba7443bcSTejun Heo return ERR_PTR(-ENOMEM); 887ba7443bcSTejun Heo } 888ba7443bcSTejun Heo 889324a56e1STejun Heo kn->priv = priv; 890adc5e8b5STejun Heo kn->dir.root = root; 891ba7443bcSTejun Heo 89290c07c89STejun Heo root->syscall_ops = scops; 893d35258efSTejun Heo root->flags = flags; 894324a56e1STejun Heo root->kn = kn; 895abd54f02STejun Heo init_waitqueue_head(&root->deactivate_waitq); 896ba7443bcSTejun Heo 897d35258efSTejun Heo if (!(root->flags & KERNFS_ROOT_CREATE_DEACTIVATED)) 898d35258efSTejun Heo kernfs_activate(kn); 899d35258efSTejun Heo 900ba7443bcSTejun Heo return root; 901ba7443bcSTejun Heo } 902ba7443bcSTejun Heo 903ba7443bcSTejun Heo /** 904ba7443bcSTejun Heo * kernfs_destroy_root - destroy a kernfs hierarchy 905ba7443bcSTejun Heo * @root: root of the hierarchy to destroy 906ba7443bcSTejun Heo * 907ba7443bcSTejun Heo * Destroy the hierarchy anchored at @root by removing all existing 908ba7443bcSTejun Heo * directories and destroying @root. 909ba7443bcSTejun Heo */ 910ba7443bcSTejun Heo void kernfs_destroy_root(struct kernfs_root *root) 911ba7443bcSTejun Heo { 912324a56e1STejun Heo kernfs_remove(root->kn); /* will also free @root */ 913ba7443bcSTejun Heo } 914ba7443bcSTejun Heo 915ba7443bcSTejun Heo /** 916fd7b9f7bSTejun Heo * kernfs_create_dir_ns - create a directory 917fd7b9f7bSTejun Heo * @parent: parent in which to create a new directory 918fd7b9f7bSTejun Heo * @name: name of the new directory 919bb8b9d09STejun Heo * @mode: mode of the new directory 920fd7b9f7bSTejun Heo * @priv: opaque data associated with the new directory 921fd7b9f7bSTejun Heo * @ns: optional namespace tag of the directory 922fd7b9f7bSTejun Heo * 923fd7b9f7bSTejun Heo * Returns the created node on success, ERR_PTR() value on failure. 924fd7b9f7bSTejun Heo */ 925324a56e1STejun Heo struct kernfs_node *kernfs_create_dir_ns(struct kernfs_node *parent, 926bb8b9d09STejun Heo const char *name, umode_t mode, 927bb8b9d09STejun Heo void *priv, const void *ns) 928fd7b9f7bSTejun Heo { 929324a56e1STejun Heo struct kernfs_node *kn; 930fd7b9f7bSTejun Heo int rc; 931fd7b9f7bSTejun Heo 932fd7b9f7bSTejun Heo /* allocate */ 933db4aad20STejun Heo kn = kernfs_new_node(parent, name, mode | S_IFDIR, KERNFS_DIR); 934324a56e1STejun Heo if (!kn) 935fd7b9f7bSTejun Heo return ERR_PTR(-ENOMEM); 936fd7b9f7bSTejun Heo 937adc5e8b5STejun Heo kn->dir.root = parent->dir.root; 938adc5e8b5STejun Heo kn->ns = ns; 939324a56e1STejun Heo kn->priv = priv; 940fd7b9f7bSTejun Heo 941fd7b9f7bSTejun Heo /* link in */ 942988cd7afSTejun Heo rc = kernfs_add_one(kn); 943fd7b9f7bSTejun Heo if (!rc) 944324a56e1STejun Heo return kn; 945fd7b9f7bSTejun Heo 946324a56e1STejun Heo kernfs_put(kn); 947fd7b9f7bSTejun Heo return ERR_PTR(rc); 948fd7b9f7bSTejun Heo } 949fd7b9f7bSTejun Heo 950ea015218SEric W. Biederman /** 951ea015218SEric W. Biederman * kernfs_create_empty_dir - create an always empty directory 952ea015218SEric W. Biederman * @parent: parent in which to create a new directory 953ea015218SEric W. Biederman * @name: name of the new directory 954ea015218SEric W. Biederman * 955ea015218SEric W. Biederman * Returns the created node on success, ERR_PTR() value on failure. 956ea015218SEric W. Biederman */ 957ea015218SEric W. Biederman struct kernfs_node *kernfs_create_empty_dir(struct kernfs_node *parent, 958ea015218SEric W. Biederman const char *name) 959ea015218SEric W. Biederman { 960ea015218SEric W. Biederman struct kernfs_node *kn; 961ea015218SEric W. Biederman int rc; 962ea015218SEric W. Biederman 963ea015218SEric W. Biederman /* allocate */ 964ea015218SEric W. Biederman kn = kernfs_new_node(parent, name, S_IRUGO|S_IXUGO|S_IFDIR, KERNFS_DIR); 965ea015218SEric W. Biederman if (!kn) 966ea015218SEric W. Biederman return ERR_PTR(-ENOMEM); 967ea015218SEric W. Biederman 968ea015218SEric W. Biederman kn->flags |= KERNFS_EMPTY_DIR; 969ea015218SEric W. Biederman kn->dir.root = parent->dir.root; 970ea015218SEric W. Biederman kn->ns = NULL; 971ea015218SEric W. Biederman kn->priv = NULL; 972ea015218SEric W. Biederman 973ea015218SEric W. Biederman /* link in */ 974ea015218SEric W. Biederman rc = kernfs_add_one(kn); 975ea015218SEric W. Biederman if (!rc) 976ea015218SEric W. Biederman return kn; 977ea015218SEric W. Biederman 978ea015218SEric W. Biederman kernfs_put(kn); 979ea015218SEric W. Biederman return ERR_PTR(rc); 980ea015218SEric W. Biederman } 981ea015218SEric W. Biederman 982c637b8acSTejun Heo static struct dentry *kernfs_iop_lookup(struct inode *dir, 983c637b8acSTejun Heo struct dentry *dentry, 984fd7b9f7bSTejun Heo unsigned int flags) 985fd7b9f7bSTejun Heo { 98619bbb926STejun Heo struct dentry *ret; 987324a56e1STejun Heo struct kernfs_node *parent = dentry->d_parent->d_fsdata; 988324a56e1STejun Heo struct kernfs_node *kn; 989fd7b9f7bSTejun Heo struct inode *inode; 990fd7b9f7bSTejun Heo const void *ns = NULL; 991fd7b9f7bSTejun Heo 992a797bfc3STejun Heo mutex_lock(&kernfs_mutex); 993fd7b9f7bSTejun Heo 994324a56e1STejun Heo if (kernfs_ns_enabled(parent)) 995c525aaddSTejun Heo ns = kernfs_info(dir->i_sb)->ns; 996fd7b9f7bSTejun Heo 997324a56e1STejun Heo kn = kernfs_find_ns(parent, dentry->d_name.name, ns); 998fd7b9f7bSTejun Heo 999fd7b9f7bSTejun Heo /* no such entry */ 1000b9c9dad0STejun Heo if (!kn || !kernfs_active(kn)) { 100119bbb926STejun Heo ret = NULL; 1002fd7b9f7bSTejun Heo goto out_unlock; 1003fd7b9f7bSTejun Heo } 1004324a56e1STejun Heo kernfs_get(kn); 1005324a56e1STejun Heo dentry->d_fsdata = kn; 1006fd7b9f7bSTejun Heo 1007fd7b9f7bSTejun Heo /* attach dentry and inode */ 1008c637b8acSTejun Heo inode = kernfs_get_inode(dir->i_sb, kn); 1009fd7b9f7bSTejun Heo if (!inode) { 1010fd7b9f7bSTejun Heo ret = ERR_PTR(-ENOMEM); 1011fd7b9f7bSTejun Heo goto out_unlock; 1012fd7b9f7bSTejun Heo } 1013fd7b9f7bSTejun Heo 1014fd7b9f7bSTejun Heo /* instantiate and hash dentry */ 101541d28bcaSAl Viro ret = d_splice_alias(inode, dentry); 1016fd7b9f7bSTejun Heo out_unlock: 1017a797bfc3STejun Heo mutex_unlock(&kernfs_mutex); 1018fd7b9f7bSTejun Heo return ret; 1019fd7b9f7bSTejun Heo } 1020fd7b9f7bSTejun Heo 102180b9bbefSTejun Heo static int kernfs_iop_mkdir(struct inode *dir, struct dentry *dentry, 102280b9bbefSTejun Heo umode_t mode) 102380b9bbefSTejun Heo { 102480b9bbefSTejun Heo struct kernfs_node *parent = dir->i_private; 102590c07c89STejun Heo struct kernfs_syscall_ops *scops = kernfs_root(parent)->syscall_ops; 102607c7530dSTejun Heo int ret; 102780b9bbefSTejun Heo 102890c07c89STejun Heo if (!scops || !scops->mkdir) 102980b9bbefSTejun Heo return -EPERM; 103080b9bbefSTejun Heo 103107c7530dSTejun Heo if (!kernfs_get_active(parent)) 103207c7530dSTejun Heo return -ENODEV; 103307c7530dSTejun Heo 103490c07c89STejun Heo ret = scops->mkdir(parent, dentry->d_name.name, mode); 103507c7530dSTejun Heo 103607c7530dSTejun Heo kernfs_put_active(parent); 103707c7530dSTejun Heo return ret; 103880b9bbefSTejun Heo } 103980b9bbefSTejun Heo 104080b9bbefSTejun Heo static int kernfs_iop_rmdir(struct inode *dir, struct dentry *dentry) 104180b9bbefSTejun Heo { 104280b9bbefSTejun Heo struct kernfs_node *kn = dentry->d_fsdata; 104390c07c89STejun Heo struct kernfs_syscall_ops *scops = kernfs_root(kn)->syscall_ops; 104407c7530dSTejun Heo int ret; 104580b9bbefSTejun Heo 104690c07c89STejun Heo if (!scops || !scops->rmdir) 104780b9bbefSTejun Heo return -EPERM; 104880b9bbefSTejun Heo 104907c7530dSTejun Heo if (!kernfs_get_active(kn)) 105007c7530dSTejun Heo return -ENODEV; 105107c7530dSTejun Heo 105290c07c89STejun Heo ret = scops->rmdir(kn); 105307c7530dSTejun Heo 105407c7530dSTejun Heo kernfs_put_active(kn); 105507c7530dSTejun Heo return ret; 105680b9bbefSTejun Heo } 105780b9bbefSTejun Heo 105880b9bbefSTejun Heo static int kernfs_iop_rename(struct inode *old_dir, struct dentry *old_dentry, 10591cd66c93SMiklos Szeredi struct inode *new_dir, struct dentry *new_dentry, 10601cd66c93SMiklos Szeredi unsigned int flags) 106180b9bbefSTejun Heo { 106280b9bbefSTejun Heo struct kernfs_node *kn = old_dentry->d_fsdata; 106380b9bbefSTejun Heo struct kernfs_node *new_parent = new_dir->i_private; 106490c07c89STejun Heo struct kernfs_syscall_ops *scops = kernfs_root(kn)->syscall_ops; 106507c7530dSTejun Heo int ret; 106680b9bbefSTejun Heo 10671cd66c93SMiklos Szeredi if (flags) 10681cd66c93SMiklos Szeredi return -EINVAL; 10691cd66c93SMiklos Szeredi 107090c07c89STejun Heo if (!scops || !scops->rename) 107180b9bbefSTejun Heo return -EPERM; 107280b9bbefSTejun Heo 107307c7530dSTejun Heo if (!kernfs_get_active(kn)) 107407c7530dSTejun Heo return -ENODEV; 107507c7530dSTejun Heo 107607c7530dSTejun Heo if (!kernfs_get_active(new_parent)) { 107707c7530dSTejun Heo kernfs_put_active(kn); 107807c7530dSTejun Heo return -ENODEV; 107907c7530dSTejun Heo } 108007c7530dSTejun Heo 108190c07c89STejun Heo ret = scops->rename(kn, new_parent, new_dentry->d_name.name); 108207c7530dSTejun Heo 108307c7530dSTejun Heo kernfs_put_active(new_parent); 108407c7530dSTejun Heo kernfs_put_active(kn); 108507c7530dSTejun Heo return ret; 108680b9bbefSTejun Heo } 108780b9bbefSTejun Heo 1088a797bfc3STejun Heo const struct inode_operations kernfs_dir_iops = { 1089c637b8acSTejun Heo .lookup = kernfs_iop_lookup, 1090c637b8acSTejun Heo .permission = kernfs_iop_permission, 1091c637b8acSTejun Heo .setattr = kernfs_iop_setattr, 1092c637b8acSTejun Heo .getattr = kernfs_iop_getattr, 1093c637b8acSTejun Heo .listxattr = kernfs_iop_listxattr, 109480b9bbefSTejun Heo 109580b9bbefSTejun Heo .mkdir = kernfs_iop_mkdir, 109680b9bbefSTejun Heo .rmdir = kernfs_iop_rmdir, 109780b9bbefSTejun Heo .rename = kernfs_iop_rename, 1098fd7b9f7bSTejun Heo }; 1099fd7b9f7bSTejun Heo 1100c637b8acSTejun Heo static struct kernfs_node *kernfs_leftmost_descendant(struct kernfs_node *pos) 1101fd7b9f7bSTejun Heo { 1102324a56e1STejun Heo struct kernfs_node *last; 1103fd7b9f7bSTejun Heo 1104fd7b9f7bSTejun Heo while (true) { 1105fd7b9f7bSTejun Heo struct rb_node *rbn; 1106fd7b9f7bSTejun Heo 1107fd7b9f7bSTejun Heo last = pos; 1108fd7b9f7bSTejun Heo 1109df23fc39STejun Heo if (kernfs_type(pos) != KERNFS_DIR) 1110fd7b9f7bSTejun Heo break; 1111fd7b9f7bSTejun Heo 1112adc5e8b5STejun Heo rbn = rb_first(&pos->dir.children); 1113fd7b9f7bSTejun Heo if (!rbn) 1114fd7b9f7bSTejun Heo break; 1115fd7b9f7bSTejun Heo 1116324a56e1STejun Heo pos = rb_to_kn(rbn); 1117fd7b9f7bSTejun Heo } 1118fd7b9f7bSTejun Heo 1119fd7b9f7bSTejun Heo return last; 1120fd7b9f7bSTejun Heo } 1121fd7b9f7bSTejun Heo 1122fd7b9f7bSTejun Heo /** 1123c637b8acSTejun Heo * kernfs_next_descendant_post - find the next descendant for post-order walk 1124fd7b9f7bSTejun Heo * @pos: the current position (%NULL to initiate traversal) 1125324a56e1STejun Heo * @root: kernfs_node whose descendants to walk 1126fd7b9f7bSTejun Heo * 1127fd7b9f7bSTejun Heo * Find the next descendant to visit for post-order traversal of @root's 1128fd7b9f7bSTejun Heo * descendants. @root is included in the iteration and the last node to be 1129fd7b9f7bSTejun Heo * visited. 1130fd7b9f7bSTejun Heo */ 1131c637b8acSTejun Heo static struct kernfs_node *kernfs_next_descendant_post(struct kernfs_node *pos, 1132324a56e1STejun Heo struct kernfs_node *root) 1133fd7b9f7bSTejun Heo { 1134fd7b9f7bSTejun Heo struct rb_node *rbn; 1135fd7b9f7bSTejun Heo 1136a797bfc3STejun Heo lockdep_assert_held(&kernfs_mutex); 1137fd7b9f7bSTejun Heo 1138fd7b9f7bSTejun Heo /* if first iteration, visit leftmost descendant which may be root */ 1139fd7b9f7bSTejun Heo if (!pos) 1140c637b8acSTejun Heo return kernfs_leftmost_descendant(root); 1141fd7b9f7bSTejun Heo 1142fd7b9f7bSTejun Heo /* if we visited @root, we're done */ 1143fd7b9f7bSTejun Heo if (pos == root) 1144fd7b9f7bSTejun Heo return NULL; 1145fd7b9f7bSTejun Heo 1146fd7b9f7bSTejun Heo /* if there's an unvisited sibling, visit its leftmost descendant */ 1147adc5e8b5STejun Heo rbn = rb_next(&pos->rb); 1148fd7b9f7bSTejun Heo if (rbn) 1149c637b8acSTejun Heo return kernfs_leftmost_descendant(rb_to_kn(rbn)); 1150fd7b9f7bSTejun Heo 1151fd7b9f7bSTejun Heo /* no sibling left, visit parent */ 1152adc5e8b5STejun Heo return pos->parent; 1153fd7b9f7bSTejun Heo } 1154fd7b9f7bSTejun Heo 1155d35258efSTejun Heo /** 1156d35258efSTejun Heo * kernfs_activate - activate a node which started deactivated 1157d35258efSTejun Heo * @kn: kernfs_node whose subtree is to be activated 1158d35258efSTejun Heo * 1159d35258efSTejun Heo * If the root has KERNFS_ROOT_CREATE_DEACTIVATED set, a newly created node 1160d35258efSTejun Heo * needs to be explicitly activated. A node which hasn't been activated 1161d35258efSTejun Heo * isn't visible to userland and deactivation is skipped during its 1162d35258efSTejun Heo * removal. This is useful to construct atomic init sequences where 1163d35258efSTejun Heo * creation of multiple nodes should either succeed or fail atomically. 1164d35258efSTejun Heo * 1165d35258efSTejun Heo * The caller is responsible for ensuring that this function is not called 1166d35258efSTejun Heo * after kernfs_remove*() is invoked on @kn. 1167d35258efSTejun Heo */ 1168d35258efSTejun Heo void kernfs_activate(struct kernfs_node *kn) 1169d35258efSTejun Heo { 1170d35258efSTejun Heo struct kernfs_node *pos; 1171d35258efSTejun Heo 1172d35258efSTejun Heo mutex_lock(&kernfs_mutex); 1173d35258efSTejun Heo 1174d35258efSTejun Heo pos = NULL; 1175d35258efSTejun Heo while ((pos = kernfs_next_descendant_post(pos, kn))) { 1176d35258efSTejun Heo if (!pos || (pos->flags & KERNFS_ACTIVATED)) 1177d35258efSTejun Heo continue; 1178d35258efSTejun Heo 1179d35258efSTejun Heo WARN_ON_ONCE(pos->parent && RB_EMPTY_NODE(&pos->rb)); 1180d35258efSTejun Heo WARN_ON_ONCE(atomic_read(&pos->active) != KN_DEACTIVATED_BIAS); 1181d35258efSTejun Heo 1182d35258efSTejun Heo atomic_sub(KN_DEACTIVATED_BIAS, &pos->active); 1183d35258efSTejun Heo pos->flags |= KERNFS_ACTIVATED; 1184d35258efSTejun Heo } 1185d35258efSTejun Heo 1186d35258efSTejun Heo mutex_unlock(&kernfs_mutex); 1187d35258efSTejun Heo } 1188d35258efSTejun Heo 1189988cd7afSTejun Heo static void __kernfs_remove(struct kernfs_node *kn) 1190fd7b9f7bSTejun Heo { 119135beab06STejun Heo struct kernfs_node *pos; 119235beab06STejun Heo 119335beab06STejun Heo lockdep_assert_held(&kernfs_mutex); 1194fd7b9f7bSTejun Heo 11956b0afc2aSTejun Heo /* 11966b0afc2aSTejun Heo * Short-circuit if non-root @kn has already finished removal. 11976b0afc2aSTejun Heo * This is for kernfs_remove_self() which plays with active ref 11986b0afc2aSTejun Heo * after removal. 11996b0afc2aSTejun Heo */ 12006b0afc2aSTejun Heo if (!kn || (kn->parent && RB_EMPTY_NODE(&kn->rb))) 1201ce9b499cSGreg Kroah-Hartman return; 1202ce9b499cSGreg Kroah-Hartman 1203c637b8acSTejun Heo pr_debug("kernfs %s: removing\n", kn->name); 1204fd7b9f7bSTejun Heo 120581c173cbSTejun Heo /* prevent any new usage under @kn by deactivating all nodes */ 120635beab06STejun Heo pos = NULL; 120735beab06STejun Heo while ((pos = kernfs_next_descendant_post(pos, kn))) 120881c173cbSTejun Heo if (kernfs_active(pos)) 120981c173cbSTejun Heo atomic_add(KN_DEACTIVATED_BIAS, &pos->active); 121035beab06STejun Heo 121135beab06STejun Heo /* deactivate and unlink the subtree node-by-node */ 1212fd7b9f7bSTejun Heo do { 121335beab06STejun Heo pos = kernfs_leftmost_descendant(kn); 121435beab06STejun Heo 121535beab06STejun Heo /* 121681c173cbSTejun Heo * kernfs_drain() drops kernfs_mutex temporarily and @pos's 121781c173cbSTejun Heo * base ref could have been put by someone else by the time 121881c173cbSTejun Heo * the function returns. Make sure it doesn't go away 121981c173cbSTejun Heo * underneath us. 122035beab06STejun Heo */ 122135beab06STejun Heo kernfs_get(pos); 122235beab06STejun Heo 1223d35258efSTejun Heo /* 1224d35258efSTejun Heo * Drain iff @kn was activated. This avoids draining and 1225d35258efSTejun Heo * its lockdep annotations for nodes which have never been 1226d35258efSTejun Heo * activated and allows embedding kernfs_remove() in create 1227d35258efSTejun Heo * error paths without worrying about draining. 1228d35258efSTejun Heo */ 1229d35258efSTejun Heo if (kn->flags & KERNFS_ACTIVATED) 123081c173cbSTejun Heo kernfs_drain(pos); 1231d35258efSTejun Heo else 1232d35258efSTejun Heo WARN_ON_ONCE(atomic_read(&kn->active) != KN_DEACTIVATED_BIAS); 123335beab06STejun Heo 123435beab06STejun Heo /* 123535beab06STejun Heo * kernfs_unlink_sibling() succeeds once per node. Use it 123635beab06STejun Heo * to decide who's responsible for cleanups. 123735beab06STejun Heo */ 123835beab06STejun Heo if (!pos->parent || kernfs_unlink_sibling(pos)) { 123935beab06STejun Heo struct kernfs_iattrs *ps_iattr = 124035beab06STejun Heo pos->parent ? pos->parent->iattr : NULL; 124135beab06STejun Heo 124235beab06STejun Heo /* update timestamps on the parent */ 124335beab06STejun Heo if (ps_iattr) { 12443a3a5fecSDeepa Dinamani ktime_get_real_ts(&ps_iattr->ia_iattr.ia_ctime); 12453a3a5fecSDeepa Dinamani ps_iattr->ia_iattr.ia_mtime = 12463a3a5fecSDeepa Dinamani ps_iattr->ia_iattr.ia_ctime; 124735beab06STejun Heo } 124835beab06STejun Heo 1249988cd7afSTejun Heo kernfs_put(pos); 125035beab06STejun Heo } 125135beab06STejun Heo 125235beab06STejun Heo kernfs_put(pos); 125335beab06STejun Heo } while (pos != kn); 1254fd7b9f7bSTejun Heo } 1255fd7b9f7bSTejun Heo 1256fd7b9f7bSTejun Heo /** 1257324a56e1STejun Heo * kernfs_remove - remove a kernfs_node recursively 1258324a56e1STejun Heo * @kn: the kernfs_node to remove 1259fd7b9f7bSTejun Heo * 1260324a56e1STejun Heo * Remove @kn along with all its subdirectories and files. 1261fd7b9f7bSTejun Heo */ 1262324a56e1STejun Heo void kernfs_remove(struct kernfs_node *kn) 1263fd7b9f7bSTejun Heo { 1264988cd7afSTejun Heo mutex_lock(&kernfs_mutex); 1265988cd7afSTejun Heo __kernfs_remove(kn); 1266988cd7afSTejun Heo mutex_unlock(&kernfs_mutex); 1267fd7b9f7bSTejun Heo } 1268fd7b9f7bSTejun Heo 1269fd7b9f7bSTejun Heo /** 12706b0afc2aSTejun Heo * kernfs_break_active_protection - break out of active protection 12716b0afc2aSTejun Heo * @kn: the self kernfs_node 12726b0afc2aSTejun Heo * 12736b0afc2aSTejun Heo * The caller must be running off of a kernfs operation which is invoked 12746b0afc2aSTejun Heo * with an active reference - e.g. one of kernfs_ops. Each invocation of 12756b0afc2aSTejun Heo * this function must also be matched with an invocation of 12766b0afc2aSTejun Heo * kernfs_unbreak_active_protection(). 12776b0afc2aSTejun Heo * 12786b0afc2aSTejun Heo * This function releases the active reference of @kn the caller is 12796b0afc2aSTejun Heo * holding. Once this function is called, @kn may be removed at any point 12806b0afc2aSTejun Heo * and the caller is solely responsible for ensuring that the objects it 12816b0afc2aSTejun Heo * dereferences are accessible. 12826b0afc2aSTejun Heo */ 12836b0afc2aSTejun Heo void kernfs_break_active_protection(struct kernfs_node *kn) 12846b0afc2aSTejun Heo { 12856b0afc2aSTejun Heo /* 12866b0afc2aSTejun Heo * Take out ourself out of the active ref dependency chain. If 12876b0afc2aSTejun Heo * we're called without an active ref, lockdep will complain. 12886b0afc2aSTejun Heo */ 12896b0afc2aSTejun Heo kernfs_put_active(kn); 12906b0afc2aSTejun Heo } 12916b0afc2aSTejun Heo 12926b0afc2aSTejun Heo /** 12936b0afc2aSTejun Heo * kernfs_unbreak_active_protection - undo kernfs_break_active_protection() 12946b0afc2aSTejun Heo * @kn: the self kernfs_node 12956b0afc2aSTejun Heo * 12966b0afc2aSTejun Heo * If kernfs_break_active_protection() was called, this function must be 12976b0afc2aSTejun Heo * invoked before finishing the kernfs operation. Note that while this 12986b0afc2aSTejun Heo * function restores the active reference, it doesn't and can't actually 12996b0afc2aSTejun Heo * restore the active protection - @kn may already or be in the process of 13006b0afc2aSTejun Heo * being removed. Once kernfs_break_active_protection() is invoked, that 13016b0afc2aSTejun Heo * protection is irreversibly gone for the kernfs operation instance. 13026b0afc2aSTejun Heo * 13036b0afc2aSTejun Heo * While this function may be called at any point after 13046b0afc2aSTejun Heo * kernfs_break_active_protection() is invoked, its most useful location 13056b0afc2aSTejun Heo * would be right before the enclosing kernfs operation returns. 13066b0afc2aSTejun Heo */ 13076b0afc2aSTejun Heo void kernfs_unbreak_active_protection(struct kernfs_node *kn) 13086b0afc2aSTejun Heo { 13096b0afc2aSTejun Heo /* 13106b0afc2aSTejun Heo * @kn->active could be in any state; however, the increment we do 13116b0afc2aSTejun Heo * here will be undone as soon as the enclosing kernfs operation 13126b0afc2aSTejun Heo * finishes and this temporary bump can't break anything. If @kn 13136b0afc2aSTejun Heo * is alive, nothing changes. If @kn is being deactivated, the 13146b0afc2aSTejun Heo * soon-to-follow put will either finish deactivation or restore 13156b0afc2aSTejun Heo * deactivated state. If @kn is already removed, the temporary 13166b0afc2aSTejun Heo * bump is guaranteed to be gone before @kn is released. 13176b0afc2aSTejun Heo */ 13186b0afc2aSTejun Heo atomic_inc(&kn->active); 13196b0afc2aSTejun Heo if (kernfs_lockdep(kn)) 13206b0afc2aSTejun Heo rwsem_acquire(&kn->dep_map, 0, 1, _RET_IP_); 13216b0afc2aSTejun Heo } 13226b0afc2aSTejun Heo 13236b0afc2aSTejun Heo /** 13246b0afc2aSTejun Heo * kernfs_remove_self - remove a kernfs_node from its own method 13256b0afc2aSTejun Heo * @kn: the self kernfs_node to remove 13266b0afc2aSTejun Heo * 13276b0afc2aSTejun Heo * The caller must be running off of a kernfs operation which is invoked 13286b0afc2aSTejun Heo * with an active reference - e.g. one of kernfs_ops. This can be used to 13296b0afc2aSTejun Heo * implement a file operation which deletes itself. 13306b0afc2aSTejun Heo * 13316b0afc2aSTejun Heo * For example, the "delete" file for a sysfs device directory can be 13326b0afc2aSTejun Heo * implemented by invoking kernfs_remove_self() on the "delete" file 13336b0afc2aSTejun Heo * itself. This function breaks the circular dependency of trying to 13346b0afc2aSTejun Heo * deactivate self while holding an active ref itself. It isn't necessary 13356b0afc2aSTejun Heo * to modify the usual removal path to use kernfs_remove_self(). The 13366b0afc2aSTejun Heo * "delete" implementation can simply invoke kernfs_remove_self() on self 13376b0afc2aSTejun Heo * before proceeding with the usual removal path. kernfs will ignore later 13386b0afc2aSTejun Heo * kernfs_remove() on self. 13396b0afc2aSTejun Heo * 13406b0afc2aSTejun Heo * kernfs_remove_self() can be called multiple times concurrently on the 13416b0afc2aSTejun Heo * same kernfs_node. Only the first one actually performs removal and 13426b0afc2aSTejun Heo * returns %true. All others will wait until the kernfs operation which 13436b0afc2aSTejun Heo * won self-removal finishes and return %false. Note that the losers wait 13446b0afc2aSTejun Heo * for the completion of not only the winning kernfs_remove_self() but also 13456b0afc2aSTejun Heo * the whole kernfs_ops which won the arbitration. This can be used to 13466b0afc2aSTejun Heo * guarantee, for example, all concurrent writes to a "delete" file to 13476b0afc2aSTejun Heo * finish only after the whole operation is complete. 13486b0afc2aSTejun Heo */ 13496b0afc2aSTejun Heo bool kernfs_remove_self(struct kernfs_node *kn) 13506b0afc2aSTejun Heo { 13516b0afc2aSTejun Heo bool ret; 13526b0afc2aSTejun Heo 13536b0afc2aSTejun Heo mutex_lock(&kernfs_mutex); 13546b0afc2aSTejun Heo kernfs_break_active_protection(kn); 13556b0afc2aSTejun Heo 13566b0afc2aSTejun Heo /* 13576b0afc2aSTejun Heo * SUICIDAL is used to arbitrate among competing invocations. Only 13586b0afc2aSTejun Heo * the first one will actually perform removal. When the removal 13596b0afc2aSTejun Heo * is complete, SUICIDED is set and the active ref is restored 13606b0afc2aSTejun Heo * while holding kernfs_mutex. The ones which lost arbitration 13616b0afc2aSTejun Heo * waits for SUICDED && drained which can happen only after the 13626b0afc2aSTejun Heo * enclosing kernfs operation which executed the winning instance 13636b0afc2aSTejun Heo * of kernfs_remove_self() finished. 13646b0afc2aSTejun Heo */ 13656b0afc2aSTejun Heo if (!(kn->flags & KERNFS_SUICIDAL)) { 13666b0afc2aSTejun Heo kn->flags |= KERNFS_SUICIDAL; 13676b0afc2aSTejun Heo __kernfs_remove(kn); 13686b0afc2aSTejun Heo kn->flags |= KERNFS_SUICIDED; 13696b0afc2aSTejun Heo ret = true; 13706b0afc2aSTejun Heo } else { 13716b0afc2aSTejun Heo wait_queue_head_t *waitq = &kernfs_root(kn)->deactivate_waitq; 13726b0afc2aSTejun Heo DEFINE_WAIT(wait); 13736b0afc2aSTejun Heo 13746b0afc2aSTejun Heo while (true) { 13756b0afc2aSTejun Heo prepare_to_wait(waitq, &wait, TASK_UNINTERRUPTIBLE); 13766b0afc2aSTejun Heo 13776b0afc2aSTejun Heo if ((kn->flags & KERNFS_SUICIDED) && 13786b0afc2aSTejun Heo atomic_read(&kn->active) == KN_DEACTIVATED_BIAS) 13796b0afc2aSTejun Heo break; 13806b0afc2aSTejun Heo 13816b0afc2aSTejun Heo mutex_unlock(&kernfs_mutex); 13826b0afc2aSTejun Heo schedule(); 13836b0afc2aSTejun Heo mutex_lock(&kernfs_mutex); 13846b0afc2aSTejun Heo } 13856b0afc2aSTejun Heo finish_wait(waitq, &wait); 13866b0afc2aSTejun Heo WARN_ON_ONCE(!RB_EMPTY_NODE(&kn->rb)); 13876b0afc2aSTejun Heo ret = false; 13886b0afc2aSTejun Heo } 13896b0afc2aSTejun Heo 13906b0afc2aSTejun Heo /* 13916b0afc2aSTejun Heo * This must be done while holding kernfs_mutex; otherwise, waiting 13926b0afc2aSTejun Heo * for SUICIDED && deactivated could finish prematurely. 13936b0afc2aSTejun Heo */ 13946b0afc2aSTejun Heo kernfs_unbreak_active_protection(kn); 13956b0afc2aSTejun Heo 13966b0afc2aSTejun Heo mutex_unlock(&kernfs_mutex); 13976b0afc2aSTejun Heo return ret; 13986b0afc2aSTejun Heo } 13996b0afc2aSTejun Heo 14006b0afc2aSTejun Heo /** 1401324a56e1STejun Heo * kernfs_remove_by_name_ns - find a kernfs_node by name and remove it 1402324a56e1STejun Heo * @parent: parent of the target 1403324a56e1STejun Heo * @name: name of the kernfs_node to remove 1404324a56e1STejun Heo * @ns: namespace tag of the kernfs_node to remove 1405fd7b9f7bSTejun Heo * 1406324a56e1STejun Heo * Look for the kernfs_node with @name and @ns under @parent and remove it. 1407324a56e1STejun Heo * Returns 0 on success, -ENOENT if such entry doesn't exist. 1408fd7b9f7bSTejun Heo */ 1409324a56e1STejun Heo int kernfs_remove_by_name_ns(struct kernfs_node *parent, const char *name, 1410fd7b9f7bSTejun Heo const void *ns) 1411fd7b9f7bSTejun Heo { 1412324a56e1STejun Heo struct kernfs_node *kn; 1413fd7b9f7bSTejun Heo 1414324a56e1STejun Heo if (!parent) { 1415c637b8acSTejun Heo WARN(1, KERN_WARNING "kernfs: can not remove '%s', no directory\n", 1416fd7b9f7bSTejun Heo name); 1417fd7b9f7bSTejun Heo return -ENOENT; 1418fd7b9f7bSTejun Heo } 1419fd7b9f7bSTejun Heo 1420988cd7afSTejun Heo mutex_lock(&kernfs_mutex); 1421fd7b9f7bSTejun Heo 1422324a56e1STejun Heo kn = kernfs_find_ns(parent, name, ns); 1423324a56e1STejun Heo if (kn) 1424988cd7afSTejun Heo __kernfs_remove(kn); 1425fd7b9f7bSTejun Heo 1426988cd7afSTejun Heo mutex_unlock(&kernfs_mutex); 1427fd7b9f7bSTejun Heo 1428324a56e1STejun Heo if (kn) 1429fd7b9f7bSTejun Heo return 0; 1430fd7b9f7bSTejun Heo else 1431fd7b9f7bSTejun Heo return -ENOENT; 1432fd7b9f7bSTejun Heo } 1433fd7b9f7bSTejun Heo 1434fd7b9f7bSTejun Heo /** 1435fd7b9f7bSTejun Heo * kernfs_rename_ns - move and rename a kernfs_node 1436324a56e1STejun Heo * @kn: target node 1437fd7b9f7bSTejun Heo * @new_parent: new parent to put @sd under 1438fd7b9f7bSTejun Heo * @new_name: new name 1439fd7b9f7bSTejun Heo * @new_ns: new namespace tag 1440fd7b9f7bSTejun Heo */ 1441324a56e1STejun Heo int kernfs_rename_ns(struct kernfs_node *kn, struct kernfs_node *new_parent, 1442fd7b9f7bSTejun Heo const char *new_name, const void *new_ns) 1443fd7b9f7bSTejun Heo { 14443eef34adSTejun Heo struct kernfs_node *old_parent; 14453eef34adSTejun Heo const char *old_name = NULL; 1446fd7b9f7bSTejun Heo int error; 1447fd7b9f7bSTejun Heo 14483eef34adSTejun Heo /* can't move or rename root */ 14493eef34adSTejun Heo if (!kn->parent) 14503eef34adSTejun Heo return -EINVAL; 14513eef34adSTejun Heo 1452ae34372eSTejun Heo mutex_lock(&kernfs_mutex); 1453d0ae3d43STejun Heo 1454798c75a0SGreg Kroah-Hartman error = -ENOENT; 1455ea015218SEric W. Biederman if (!kernfs_active(kn) || !kernfs_active(new_parent) || 1456ea015218SEric W. Biederman (new_parent->flags & KERNFS_EMPTY_DIR)) 1457798c75a0SGreg Kroah-Hartman goto out; 1458798c75a0SGreg Kroah-Hartman 1459fd7b9f7bSTejun Heo error = 0; 1460adc5e8b5STejun Heo if ((kn->parent == new_parent) && (kn->ns == new_ns) && 1461adc5e8b5STejun Heo (strcmp(kn->name, new_name) == 0)) 1462798c75a0SGreg Kroah-Hartman goto out; /* nothing to rename */ 1463fd7b9f7bSTejun Heo 1464fd7b9f7bSTejun Heo error = -EEXIST; 1465fd7b9f7bSTejun Heo if (kernfs_find_ns(new_parent, new_name, new_ns)) 1466798c75a0SGreg Kroah-Hartman goto out; 1467fd7b9f7bSTejun Heo 1468324a56e1STejun Heo /* rename kernfs_node */ 1469adc5e8b5STejun Heo if (strcmp(kn->name, new_name) != 0) { 1470fd7b9f7bSTejun Heo error = -ENOMEM; 147175287a67SAndrzej Hajda new_name = kstrdup_const(new_name, GFP_KERNEL); 1472fd7b9f7bSTejun Heo if (!new_name) 1473798c75a0SGreg Kroah-Hartman goto out; 14743eef34adSTejun Heo } else { 14753eef34adSTejun Heo new_name = NULL; 1476fd7b9f7bSTejun Heo } 1477fd7b9f7bSTejun Heo 1478fd7b9f7bSTejun Heo /* 1479fd7b9f7bSTejun Heo * Move to the appropriate place in the appropriate directories rbtree. 1480fd7b9f7bSTejun Heo */ 1481c637b8acSTejun Heo kernfs_unlink_sibling(kn); 1482fd7b9f7bSTejun Heo kernfs_get(new_parent); 14833eef34adSTejun Heo 14843eef34adSTejun Heo /* rename_lock protects ->parent and ->name accessors */ 14853eef34adSTejun Heo spin_lock_irq(&kernfs_rename_lock); 14863eef34adSTejun Heo 14873eef34adSTejun Heo old_parent = kn->parent; 1488adc5e8b5STejun Heo kn->parent = new_parent; 14893eef34adSTejun Heo 14903eef34adSTejun Heo kn->ns = new_ns; 14913eef34adSTejun Heo if (new_name) { 14923eef34adSTejun Heo old_name = kn->name; 14933eef34adSTejun Heo kn->name = new_name; 14943eef34adSTejun Heo } 14953eef34adSTejun Heo 14963eef34adSTejun Heo spin_unlock_irq(&kernfs_rename_lock); 14973eef34adSTejun Heo 14989561a896STejun Heo kn->hash = kernfs_name_hash(kn->name, kn->ns); 1499c637b8acSTejun Heo kernfs_link_sibling(kn); 1500fd7b9f7bSTejun Heo 15013eef34adSTejun Heo kernfs_put(old_parent); 150275287a67SAndrzej Hajda kfree_const(old_name); 15033eef34adSTejun Heo 1504fd7b9f7bSTejun Heo error = 0; 1505ae34372eSTejun Heo out: 1506798c75a0SGreg Kroah-Hartman mutex_unlock(&kernfs_mutex); 1507fd7b9f7bSTejun Heo return error; 1508fd7b9f7bSTejun Heo } 1509fd7b9f7bSTejun Heo 1510fd7b9f7bSTejun Heo /* Relationship between s_mode and the DT_xxx types */ 1511324a56e1STejun Heo static inline unsigned char dt_type(struct kernfs_node *kn) 1512fd7b9f7bSTejun Heo { 1513adc5e8b5STejun Heo return (kn->mode >> 12) & 15; 1514fd7b9f7bSTejun Heo } 1515fd7b9f7bSTejun Heo 1516c637b8acSTejun Heo static int kernfs_dir_fop_release(struct inode *inode, struct file *filp) 1517fd7b9f7bSTejun Heo { 1518fd7b9f7bSTejun Heo kernfs_put(filp->private_data); 1519fd7b9f7bSTejun Heo return 0; 1520fd7b9f7bSTejun Heo } 1521fd7b9f7bSTejun Heo 1522c637b8acSTejun Heo static struct kernfs_node *kernfs_dir_pos(const void *ns, 1523324a56e1STejun Heo struct kernfs_node *parent, loff_t hash, struct kernfs_node *pos) 1524fd7b9f7bSTejun Heo { 1525fd7b9f7bSTejun Heo if (pos) { 152681c173cbSTejun Heo int valid = kernfs_active(pos) && 1527798c75a0SGreg Kroah-Hartman pos->parent == parent && hash == pos->hash; 1528fd7b9f7bSTejun Heo kernfs_put(pos); 1529fd7b9f7bSTejun Heo if (!valid) 1530fd7b9f7bSTejun Heo pos = NULL; 1531fd7b9f7bSTejun Heo } 1532fd7b9f7bSTejun Heo if (!pos && (hash > 1) && (hash < INT_MAX)) { 1533adc5e8b5STejun Heo struct rb_node *node = parent->dir.children.rb_node; 1534fd7b9f7bSTejun Heo while (node) { 1535324a56e1STejun Heo pos = rb_to_kn(node); 1536fd7b9f7bSTejun Heo 1537adc5e8b5STejun Heo if (hash < pos->hash) 1538fd7b9f7bSTejun Heo node = node->rb_left; 1539adc5e8b5STejun Heo else if (hash > pos->hash) 1540fd7b9f7bSTejun Heo node = node->rb_right; 1541fd7b9f7bSTejun Heo else 1542fd7b9f7bSTejun Heo break; 1543fd7b9f7bSTejun Heo } 1544fd7b9f7bSTejun Heo } 1545b9c9dad0STejun Heo /* Skip over entries which are dying/dead or in the wrong namespace */ 1546b9c9dad0STejun Heo while (pos && (!kernfs_active(pos) || pos->ns != ns)) { 1547adc5e8b5STejun Heo struct rb_node *node = rb_next(&pos->rb); 1548fd7b9f7bSTejun Heo if (!node) 1549fd7b9f7bSTejun Heo pos = NULL; 1550fd7b9f7bSTejun Heo else 1551324a56e1STejun Heo pos = rb_to_kn(node); 1552fd7b9f7bSTejun Heo } 1553fd7b9f7bSTejun Heo return pos; 1554fd7b9f7bSTejun Heo } 1555fd7b9f7bSTejun Heo 1556c637b8acSTejun Heo static struct kernfs_node *kernfs_dir_next_pos(const void *ns, 1557324a56e1STejun Heo struct kernfs_node *parent, ino_t ino, struct kernfs_node *pos) 1558fd7b9f7bSTejun Heo { 1559c637b8acSTejun Heo pos = kernfs_dir_pos(ns, parent, ino, pos); 1560b9c9dad0STejun Heo if (pos) { 1561fd7b9f7bSTejun Heo do { 1562adc5e8b5STejun Heo struct rb_node *node = rb_next(&pos->rb); 1563fd7b9f7bSTejun Heo if (!node) 1564fd7b9f7bSTejun Heo pos = NULL; 1565fd7b9f7bSTejun Heo else 1566324a56e1STejun Heo pos = rb_to_kn(node); 1567b9c9dad0STejun Heo } while (pos && (!kernfs_active(pos) || pos->ns != ns)); 1568b9c9dad0STejun Heo } 1569fd7b9f7bSTejun Heo return pos; 1570fd7b9f7bSTejun Heo } 1571fd7b9f7bSTejun Heo 1572c637b8acSTejun Heo static int kernfs_fop_readdir(struct file *file, struct dir_context *ctx) 1573fd7b9f7bSTejun Heo { 1574fd7b9f7bSTejun Heo struct dentry *dentry = file->f_path.dentry; 1575324a56e1STejun Heo struct kernfs_node *parent = dentry->d_fsdata; 1576324a56e1STejun Heo struct kernfs_node *pos = file->private_data; 1577fd7b9f7bSTejun Heo const void *ns = NULL; 1578fd7b9f7bSTejun Heo 1579fd7b9f7bSTejun Heo if (!dir_emit_dots(file, ctx)) 1580fd7b9f7bSTejun Heo return 0; 1581a797bfc3STejun Heo mutex_lock(&kernfs_mutex); 1582fd7b9f7bSTejun Heo 1583324a56e1STejun Heo if (kernfs_ns_enabled(parent)) 1584c525aaddSTejun Heo ns = kernfs_info(dentry->d_sb)->ns; 1585fd7b9f7bSTejun Heo 1586c637b8acSTejun Heo for (pos = kernfs_dir_pos(ns, parent, ctx->pos, pos); 1587fd7b9f7bSTejun Heo pos; 1588c637b8acSTejun Heo pos = kernfs_dir_next_pos(ns, parent, ctx->pos, pos)) { 1589adc5e8b5STejun Heo const char *name = pos->name; 1590fd7b9f7bSTejun Heo unsigned int type = dt_type(pos); 1591fd7b9f7bSTejun Heo int len = strlen(name); 1592adc5e8b5STejun Heo ino_t ino = pos->ino; 1593fd7b9f7bSTejun Heo 1594adc5e8b5STejun Heo ctx->pos = pos->hash; 1595fd7b9f7bSTejun Heo file->private_data = pos; 1596fd7b9f7bSTejun Heo kernfs_get(pos); 1597fd7b9f7bSTejun Heo 1598a797bfc3STejun Heo mutex_unlock(&kernfs_mutex); 1599fd7b9f7bSTejun Heo if (!dir_emit(ctx, name, len, ino, type)) 1600fd7b9f7bSTejun Heo return 0; 1601a797bfc3STejun Heo mutex_lock(&kernfs_mutex); 1602fd7b9f7bSTejun Heo } 1603a797bfc3STejun Heo mutex_unlock(&kernfs_mutex); 1604fd7b9f7bSTejun Heo file->private_data = NULL; 1605fd7b9f7bSTejun Heo ctx->pos = INT_MAX; 1606fd7b9f7bSTejun Heo return 0; 1607fd7b9f7bSTejun Heo } 1608fd7b9f7bSTejun Heo 1609a797bfc3STejun Heo const struct file_operations kernfs_dir_fops = { 1610fd7b9f7bSTejun Heo .read = generic_read_dir, 16118cb0d2c1SAl Viro .iterate_shared = kernfs_fop_readdir, 1612c637b8acSTejun Heo .release = kernfs_dir_fop_release, 16138cb0d2c1SAl Viro .llseek = generic_file_llseek, 1614fd7b9f7bSTejun Heo }; 1615