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 */ 247d35079fSShaohua Li static DEFINE_SPINLOCK(kernfs_idr_lock); /* root->ino_idr */ 25fd7b9f7bSTejun Heo 26adc5e8b5STejun Heo #define rb_to_kn(X) rb_entry((X), struct kernfs_node, rb) 27fd7b9f7bSTejun Heo 2881c173cbSTejun Heo static bool kernfs_active(struct kernfs_node *kn) 2981c173cbSTejun Heo { 3081c173cbSTejun Heo lockdep_assert_held(&kernfs_mutex); 3181c173cbSTejun Heo return atomic_read(&kn->active) >= 0; 3281c173cbSTejun Heo } 3381c173cbSTejun Heo 34182fd64bSTejun Heo static bool kernfs_lockdep(struct kernfs_node *kn) 35182fd64bSTejun Heo { 36182fd64bSTejun Heo #ifdef CONFIG_DEBUG_LOCK_ALLOC 37182fd64bSTejun Heo return kn->flags & KERNFS_LOCKDEP; 38182fd64bSTejun Heo #else 39182fd64bSTejun Heo return false; 40182fd64bSTejun Heo #endif 41182fd64bSTejun Heo } 42182fd64bSTejun Heo 433eef34adSTejun Heo static int kernfs_name_locked(struct kernfs_node *kn, char *buf, size_t buflen) 443eef34adSTejun Heo { 4517627157SKonstantin Khlebnikov if (!kn) 4617627157SKonstantin Khlebnikov return strlcpy(buf, "(null)", buflen); 4717627157SKonstantin Khlebnikov 483eef34adSTejun Heo return strlcpy(buf, kn->parent ? kn->name : "/", buflen); 493eef34adSTejun Heo } 503eef34adSTejun Heo 519f6df573SAditya Kali /* kernfs_node_depth - compute depth from @from to @to */ 529f6df573SAditya Kali static size_t kernfs_depth(struct kernfs_node *from, struct kernfs_node *to) 533eef34adSTejun Heo { 549f6df573SAditya Kali size_t depth = 0; 553eef34adSTejun Heo 569f6df573SAditya Kali while (to->parent && to != from) { 579f6df573SAditya Kali depth++; 589f6df573SAditya Kali to = to->parent; 593eef34adSTejun Heo } 609f6df573SAditya Kali return depth; 619f6df573SAditya Kali } 623eef34adSTejun Heo 639f6df573SAditya Kali static struct kernfs_node *kernfs_common_ancestor(struct kernfs_node *a, 649f6df573SAditya Kali struct kernfs_node *b) 659f6df573SAditya Kali { 669f6df573SAditya Kali size_t da, db; 679f6df573SAditya Kali struct kernfs_root *ra = kernfs_root(a), *rb = kernfs_root(b); 689f6df573SAditya Kali 699f6df573SAditya Kali if (ra != rb) 709f6df573SAditya Kali return NULL; 719f6df573SAditya Kali 729f6df573SAditya Kali da = kernfs_depth(ra->kn, a); 739f6df573SAditya Kali db = kernfs_depth(rb->kn, b); 749f6df573SAditya Kali 759f6df573SAditya Kali while (da > db) { 769f6df573SAditya Kali a = a->parent; 779f6df573SAditya Kali da--; 789f6df573SAditya Kali } 799f6df573SAditya Kali while (db > da) { 809f6df573SAditya Kali b = b->parent; 819f6df573SAditya Kali db--; 829f6df573SAditya Kali } 839f6df573SAditya Kali 849f6df573SAditya Kali /* worst case b and a will be the same at root */ 859f6df573SAditya Kali while (b != a) { 869f6df573SAditya Kali b = b->parent; 879f6df573SAditya Kali a = a->parent; 889f6df573SAditya Kali } 899f6df573SAditya Kali 909f6df573SAditya Kali return a; 919f6df573SAditya Kali } 929f6df573SAditya Kali 939f6df573SAditya Kali /** 949f6df573SAditya Kali * kernfs_path_from_node_locked - find a pseudo-absolute path to @kn_to, 959f6df573SAditya Kali * where kn_from is treated as root of the path. 969f6df573SAditya Kali * @kn_from: kernfs node which should be treated as root for the path 979f6df573SAditya Kali * @kn_to: kernfs node to which path is needed 989f6df573SAditya Kali * @buf: buffer to copy the path into 999f6df573SAditya Kali * @buflen: size of @buf 1009f6df573SAditya Kali * 1019f6df573SAditya Kali * We need to handle couple of scenarios here: 1029f6df573SAditya Kali * [1] when @kn_from is an ancestor of @kn_to at some level 1039f6df573SAditya Kali * kn_from: /n1/n2/n3 1049f6df573SAditya Kali * kn_to: /n1/n2/n3/n4/n5 1059f6df573SAditya Kali * result: /n4/n5 1069f6df573SAditya Kali * 1079f6df573SAditya Kali * [2] when @kn_from is on a different hierarchy and we need to find common 1089f6df573SAditya Kali * ancestor between @kn_from and @kn_to. 1099f6df573SAditya Kali * kn_from: /n1/n2/n3/n4 1109f6df573SAditya Kali * kn_to: /n1/n2/n5 1119f6df573SAditya Kali * result: /../../n5 1129f6df573SAditya Kali * OR 1139f6df573SAditya Kali * kn_from: /n1/n2/n3/n4/n5 [depth=5] 1149f6df573SAditya Kali * kn_to: /n1/n2/n3 [depth=3] 1159f6df573SAditya Kali * result: /../.. 1169f6df573SAditya Kali * 11717627157SKonstantin Khlebnikov * [3] when @kn_to is NULL result will be "(null)" 11817627157SKonstantin Khlebnikov * 1193abb1d90STejun Heo * Returns the length of the full path. If the full length is equal to or 1203abb1d90STejun Heo * greater than @buflen, @buf contains the truncated path with the trailing 1213abb1d90STejun Heo * '\0'. On error, -errno is returned. 1229f6df573SAditya Kali */ 1239f6df573SAditya Kali static int kernfs_path_from_node_locked(struct kernfs_node *kn_to, 1249f6df573SAditya Kali struct kernfs_node *kn_from, 1259f6df573SAditya Kali char *buf, size_t buflen) 1269f6df573SAditya Kali { 1279f6df573SAditya Kali struct kernfs_node *kn, *common; 1289f6df573SAditya Kali const char parent_str[] = "/.."; 1293abb1d90STejun Heo size_t depth_from, depth_to, len = 0; 1303abb1d90STejun Heo int i, j; 1319f6df573SAditya Kali 13217627157SKonstantin Khlebnikov if (!kn_to) 13317627157SKonstantin Khlebnikov return strlcpy(buf, "(null)", buflen); 13417627157SKonstantin Khlebnikov 1359f6df573SAditya Kali if (!kn_from) 1369f6df573SAditya Kali kn_from = kernfs_root(kn_to)->kn; 1379f6df573SAditya Kali 1389f6df573SAditya Kali if (kn_from == kn_to) 1399f6df573SAditya Kali return strlcpy(buf, "/", buflen); 1409f6df573SAditya Kali 1419f6df573SAditya Kali common = kernfs_common_ancestor(kn_from, kn_to); 1429f6df573SAditya Kali if (WARN_ON(!common)) 1433abb1d90STejun Heo return -EINVAL; 1449f6df573SAditya Kali 1459f6df573SAditya Kali depth_to = kernfs_depth(common, kn_to); 1469f6df573SAditya Kali depth_from = kernfs_depth(common, kn_from); 1479f6df573SAditya Kali 1489f6df573SAditya Kali if (buf) 1499f6df573SAditya Kali buf[0] = '\0'; 1509f6df573SAditya Kali 1519f6df573SAditya Kali for (i = 0; i < depth_from; i++) 1529f6df573SAditya Kali len += strlcpy(buf + len, parent_str, 1539f6df573SAditya Kali len < buflen ? buflen - len : 0); 1549f6df573SAditya Kali 1559f6df573SAditya Kali /* Calculate how many bytes we need for the rest */ 1563abb1d90STejun Heo for (i = depth_to - 1; i >= 0; i--) { 1573abb1d90STejun Heo for (kn = kn_to, j = 0; j < i; j++) 1583abb1d90STejun Heo kn = kn->parent; 1593abb1d90STejun Heo len += strlcpy(buf + len, "/", 1603abb1d90STejun Heo len < buflen ? buflen - len : 0); 1613abb1d90STejun Heo len += strlcpy(buf + len, kn->name, 1623abb1d90STejun Heo len < buflen ? buflen - len : 0); 1639f6df573SAditya Kali } 1649f6df573SAditya Kali 1653abb1d90STejun Heo return len; 1663eef34adSTejun Heo } 1673eef34adSTejun Heo 1683eef34adSTejun Heo /** 1693eef34adSTejun Heo * kernfs_name - obtain the name of a given node 1703eef34adSTejun Heo * @kn: kernfs_node of interest 1713eef34adSTejun Heo * @buf: buffer to copy @kn's name into 1723eef34adSTejun Heo * @buflen: size of @buf 1733eef34adSTejun Heo * 1743eef34adSTejun Heo * Copies the name of @kn into @buf of @buflen bytes. The behavior is 1753eef34adSTejun Heo * similar to strlcpy(). It returns the length of @kn's name and if @buf 1763eef34adSTejun Heo * isn't long enough, it's filled upto @buflen-1 and nul terminated. 1773eef34adSTejun Heo * 17817627157SKonstantin Khlebnikov * Fills buffer with "(null)" if @kn is NULL. 17917627157SKonstantin Khlebnikov * 1803eef34adSTejun Heo * This function can be called from any context. 1813eef34adSTejun Heo */ 1823eef34adSTejun Heo int kernfs_name(struct kernfs_node *kn, char *buf, size_t buflen) 1833eef34adSTejun Heo { 1843eef34adSTejun Heo unsigned long flags; 1853eef34adSTejun Heo int ret; 1863eef34adSTejun Heo 1873eef34adSTejun Heo spin_lock_irqsave(&kernfs_rename_lock, flags); 1883eef34adSTejun Heo ret = kernfs_name_locked(kn, buf, buflen); 1893eef34adSTejun Heo spin_unlock_irqrestore(&kernfs_rename_lock, flags); 1903eef34adSTejun Heo return ret; 1913eef34adSTejun Heo } 1923eef34adSTejun Heo 1933eef34adSTejun Heo /** 1949f6df573SAditya Kali * kernfs_path_from_node - build path of node @to relative to @from. 1959f6df573SAditya Kali * @from: parent kernfs_node relative to which we need to build the path 1969f6df573SAditya Kali * @to: kernfs_node of interest 1979f6df573SAditya Kali * @buf: buffer to copy @to's path into 1989f6df573SAditya Kali * @buflen: size of @buf 1999f6df573SAditya Kali * 2009f6df573SAditya Kali * Builds @to's path relative to @from in @buf. @from and @to must 2019f6df573SAditya Kali * be on the same kernfs-root. If @from is not parent of @to, then a relative 2029f6df573SAditya Kali * path (which includes '..'s) as needed to reach from @from to @to is 2039f6df573SAditya Kali * returned. 2049f6df573SAditya Kali * 2053abb1d90STejun Heo * Returns the length of the full path. If the full length is equal to or 2063abb1d90STejun Heo * greater than @buflen, @buf contains the truncated path with the trailing 2073abb1d90STejun Heo * '\0'. On error, -errno is returned. 2089f6df573SAditya Kali */ 2099f6df573SAditya Kali int kernfs_path_from_node(struct kernfs_node *to, struct kernfs_node *from, 2109f6df573SAditya Kali char *buf, size_t buflen) 2119f6df573SAditya Kali { 2129f6df573SAditya Kali unsigned long flags; 2139f6df573SAditya Kali int ret; 2149f6df573SAditya Kali 2159f6df573SAditya Kali spin_lock_irqsave(&kernfs_rename_lock, flags); 2169f6df573SAditya Kali ret = kernfs_path_from_node_locked(to, from, buf, buflen); 2179f6df573SAditya Kali spin_unlock_irqrestore(&kernfs_rename_lock, flags); 2189f6df573SAditya Kali return ret; 2199f6df573SAditya Kali } 2209f6df573SAditya Kali EXPORT_SYMBOL_GPL(kernfs_path_from_node); 2219f6df573SAditya Kali 2229f6df573SAditya Kali /** 2233eef34adSTejun Heo * pr_cont_kernfs_name - pr_cont name of a kernfs_node 2243eef34adSTejun Heo * @kn: kernfs_node of interest 2253eef34adSTejun Heo * 2263eef34adSTejun Heo * This function can be called from any context. 2273eef34adSTejun Heo */ 2283eef34adSTejun Heo void pr_cont_kernfs_name(struct kernfs_node *kn) 2293eef34adSTejun Heo { 2303eef34adSTejun Heo unsigned long flags; 2313eef34adSTejun Heo 2323eef34adSTejun Heo spin_lock_irqsave(&kernfs_rename_lock, flags); 2333eef34adSTejun Heo 2343eef34adSTejun Heo kernfs_name_locked(kn, kernfs_pr_cont_buf, sizeof(kernfs_pr_cont_buf)); 2353eef34adSTejun Heo pr_cont("%s", kernfs_pr_cont_buf); 2363eef34adSTejun Heo 2373eef34adSTejun Heo spin_unlock_irqrestore(&kernfs_rename_lock, flags); 2383eef34adSTejun Heo } 2393eef34adSTejun Heo 2403eef34adSTejun Heo /** 2413eef34adSTejun Heo * pr_cont_kernfs_path - pr_cont path of a kernfs_node 2423eef34adSTejun Heo * @kn: kernfs_node of interest 2433eef34adSTejun Heo * 2443eef34adSTejun Heo * This function can be called from any context. 2453eef34adSTejun Heo */ 2463eef34adSTejun Heo void pr_cont_kernfs_path(struct kernfs_node *kn) 2473eef34adSTejun Heo { 2483eef34adSTejun Heo unsigned long flags; 2499f6df573SAditya Kali int sz; 2503eef34adSTejun Heo 2513eef34adSTejun Heo spin_lock_irqsave(&kernfs_rename_lock, flags); 2523eef34adSTejun Heo 2539f6df573SAditya Kali sz = kernfs_path_from_node_locked(kn, NULL, kernfs_pr_cont_buf, 2543eef34adSTejun Heo sizeof(kernfs_pr_cont_buf)); 2559f6df573SAditya Kali if (sz < 0) { 2569f6df573SAditya Kali pr_cont("(error)"); 2579f6df573SAditya Kali goto out; 2589f6df573SAditya Kali } 2593eef34adSTejun Heo 2609f6df573SAditya Kali if (sz >= sizeof(kernfs_pr_cont_buf)) { 2619f6df573SAditya Kali pr_cont("(name too long)"); 2629f6df573SAditya Kali goto out; 2639f6df573SAditya Kali } 2649f6df573SAditya Kali 2659f6df573SAditya Kali pr_cont("%s", kernfs_pr_cont_buf); 2669f6df573SAditya Kali 2679f6df573SAditya Kali out: 2683eef34adSTejun Heo spin_unlock_irqrestore(&kernfs_rename_lock, flags); 2693eef34adSTejun Heo } 2703eef34adSTejun Heo 2713eef34adSTejun Heo /** 2723eef34adSTejun Heo * kernfs_get_parent - determine the parent node and pin it 2733eef34adSTejun Heo * @kn: kernfs_node of interest 2743eef34adSTejun Heo * 2753eef34adSTejun Heo * Determines @kn's parent, pins and returns it. This function can be 2763eef34adSTejun Heo * called from any context. 2773eef34adSTejun Heo */ 2783eef34adSTejun Heo struct kernfs_node *kernfs_get_parent(struct kernfs_node *kn) 2793eef34adSTejun Heo { 2803eef34adSTejun Heo struct kernfs_node *parent; 2813eef34adSTejun Heo unsigned long flags; 2823eef34adSTejun Heo 2833eef34adSTejun Heo spin_lock_irqsave(&kernfs_rename_lock, flags); 2843eef34adSTejun Heo parent = kn->parent; 2853eef34adSTejun Heo kernfs_get(parent); 2863eef34adSTejun Heo spin_unlock_irqrestore(&kernfs_rename_lock, flags); 2873eef34adSTejun Heo 2883eef34adSTejun Heo return parent; 2893eef34adSTejun Heo } 2903eef34adSTejun Heo 291fd7b9f7bSTejun Heo /** 292c637b8acSTejun Heo * kernfs_name_hash 293fd7b9f7bSTejun Heo * @name: Null terminated string to hash 294fd7b9f7bSTejun Heo * @ns: Namespace tag to hash 295fd7b9f7bSTejun Heo * 296fd7b9f7bSTejun Heo * Returns 31 bit hash of ns + name (so it fits in an off_t ) 297fd7b9f7bSTejun Heo */ 298c637b8acSTejun Heo static unsigned int kernfs_name_hash(const char *name, const void *ns) 299fd7b9f7bSTejun Heo { 3008387ff25SLinus Torvalds unsigned long hash = init_name_hash(ns); 301fd7b9f7bSTejun Heo unsigned int len = strlen(name); 302fd7b9f7bSTejun Heo while (len--) 303fd7b9f7bSTejun Heo hash = partial_name_hash(*name++, hash); 3048387ff25SLinus Torvalds hash = end_name_hash(hash); 305fd7b9f7bSTejun Heo hash &= 0x7fffffffU; 306fd7b9f7bSTejun Heo /* Reserve hash numbers 0, 1 and INT_MAX for magic directory entries */ 30788391d49SRichard Cochran if (hash < 2) 308fd7b9f7bSTejun Heo hash += 2; 309fd7b9f7bSTejun Heo if (hash >= INT_MAX) 310fd7b9f7bSTejun Heo hash = INT_MAX - 1; 311fd7b9f7bSTejun Heo return hash; 312fd7b9f7bSTejun Heo } 313fd7b9f7bSTejun Heo 314c637b8acSTejun Heo static int kernfs_name_compare(unsigned int hash, const char *name, 315324a56e1STejun Heo const void *ns, const struct kernfs_node *kn) 316fd7b9f7bSTejun Heo { 31772392ed0SRasmus Villemoes if (hash < kn->hash) 31872392ed0SRasmus Villemoes return -1; 31972392ed0SRasmus Villemoes if (hash > kn->hash) 32072392ed0SRasmus Villemoes return 1; 32172392ed0SRasmus Villemoes if (ns < kn->ns) 32272392ed0SRasmus Villemoes return -1; 32372392ed0SRasmus Villemoes if (ns > kn->ns) 32472392ed0SRasmus Villemoes return 1; 325adc5e8b5STejun Heo return strcmp(name, kn->name); 326fd7b9f7bSTejun Heo } 327fd7b9f7bSTejun Heo 328c637b8acSTejun Heo static int kernfs_sd_compare(const struct kernfs_node *left, 329324a56e1STejun Heo const struct kernfs_node *right) 330fd7b9f7bSTejun Heo { 331c637b8acSTejun Heo return kernfs_name_compare(left->hash, left->name, left->ns, right); 332fd7b9f7bSTejun Heo } 333fd7b9f7bSTejun Heo 334fd7b9f7bSTejun Heo /** 335c637b8acSTejun Heo * kernfs_link_sibling - link kernfs_node into sibling rbtree 336324a56e1STejun Heo * @kn: kernfs_node of interest 337fd7b9f7bSTejun Heo * 338324a56e1STejun Heo * Link @kn into its sibling rbtree which starts from 339adc5e8b5STejun Heo * @kn->parent->dir.children. 340fd7b9f7bSTejun Heo * 341fd7b9f7bSTejun Heo * Locking: 342a797bfc3STejun Heo * mutex_lock(kernfs_mutex) 343fd7b9f7bSTejun Heo * 344fd7b9f7bSTejun Heo * RETURNS: 345fd7b9f7bSTejun Heo * 0 on susccess -EEXIST on failure. 346fd7b9f7bSTejun Heo */ 347c637b8acSTejun Heo static int kernfs_link_sibling(struct kernfs_node *kn) 348fd7b9f7bSTejun Heo { 349adc5e8b5STejun Heo struct rb_node **node = &kn->parent->dir.children.rb_node; 350fd7b9f7bSTejun Heo struct rb_node *parent = NULL; 351fd7b9f7bSTejun Heo 352fd7b9f7bSTejun Heo while (*node) { 353324a56e1STejun Heo struct kernfs_node *pos; 354fd7b9f7bSTejun Heo int result; 355fd7b9f7bSTejun Heo 356324a56e1STejun Heo pos = rb_to_kn(*node); 357fd7b9f7bSTejun Heo parent = *node; 358c637b8acSTejun Heo result = kernfs_sd_compare(kn, pos); 359fd7b9f7bSTejun Heo if (result < 0) 360adc5e8b5STejun Heo node = &pos->rb.rb_left; 361fd7b9f7bSTejun Heo else if (result > 0) 362adc5e8b5STejun Heo node = &pos->rb.rb_right; 363fd7b9f7bSTejun Heo else 364fd7b9f7bSTejun Heo return -EEXIST; 365fd7b9f7bSTejun Heo } 366c1befb88SJianyu Zhan 367fd7b9f7bSTejun Heo /* add new node and rebalance the tree */ 368adc5e8b5STejun Heo rb_link_node(&kn->rb, parent, node); 369adc5e8b5STejun Heo rb_insert_color(&kn->rb, &kn->parent->dir.children); 370c1befb88SJianyu Zhan 371c1befb88SJianyu Zhan /* successfully added, account subdir number */ 372c1befb88SJianyu Zhan if (kernfs_type(kn) == KERNFS_DIR) 373c1befb88SJianyu Zhan kn->parent->dir.subdirs++; 374c1befb88SJianyu Zhan 375fd7b9f7bSTejun Heo return 0; 376fd7b9f7bSTejun Heo } 377fd7b9f7bSTejun Heo 378fd7b9f7bSTejun Heo /** 379c637b8acSTejun Heo * kernfs_unlink_sibling - unlink kernfs_node from sibling rbtree 380324a56e1STejun Heo * @kn: kernfs_node of interest 381fd7b9f7bSTejun Heo * 38235beab06STejun Heo * Try to unlink @kn from its sibling rbtree which starts from 38335beab06STejun Heo * kn->parent->dir.children. Returns %true if @kn was actually 38435beab06STejun Heo * removed, %false if @kn wasn't on the rbtree. 385fd7b9f7bSTejun Heo * 386fd7b9f7bSTejun Heo * Locking: 387a797bfc3STejun Heo * mutex_lock(kernfs_mutex) 388fd7b9f7bSTejun Heo */ 38935beab06STejun Heo static bool kernfs_unlink_sibling(struct kernfs_node *kn) 390fd7b9f7bSTejun Heo { 39135beab06STejun Heo if (RB_EMPTY_NODE(&kn->rb)) 39235beab06STejun Heo return false; 39335beab06STejun Heo 394df23fc39STejun Heo if (kernfs_type(kn) == KERNFS_DIR) 395adc5e8b5STejun Heo kn->parent->dir.subdirs--; 396fd7b9f7bSTejun Heo 397adc5e8b5STejun Heo rb_erase(&kn->rb, &kn->parent->dir.children); 39835beab06STejun Heo RB_CLEAR_NODE(&kn->rb); 39935beab06STejun Heo return true; 400fd7b9f7bSTejun Heo } 401fd7b9f7bSTejun Heo 402fd7b9f7bSTejun Heo /** 403c637b8acSTejun Heo * kernfs_get_active - get an active reference to kernfs_node 404324a56e1STejun Heo * @kn: kernfs_node to get an active reference to 405fd7b9f7bSTejun Heo * 406324a56e1STejun Heo * Get an active reference of @kn. This function is noop if @kn 407fd7b9f7bSTejun Heo * is NULL. 408fd7b9f7bSTejun Heo * 409fd7b9f7bSTejun Heo * RETURNS: 410324a56e1STejun Heo * Pointer to @kn on success, NULL on failure. 411fd7b9f7bSTejun Heo */ 412c637b8acSTejun Heo struct kernfs_node *kernfs_get_active(struct kernfs_node *kn) 413fd7b9f7bSTejun Heo { 414324a56e1STejun Heo if (unlikely(!kn)) 415fd7b9f7bSTejun Heo return NULL; 416fd7b9f7bSTejun Heo 417f4b3e631SGreg Kroah-Hartman if (!atomic_inc_unless_negative(&kn->active)) 418f4b3e631SGreg Kroah-Hartman return NULL; 419f4b3e631SGreg Kroah-Hartman 420182fd64bSTejun Heo if (kernfs_lockdep(kn)) 421324a56e1STejun Heo rwsem_acquire_read(&kn->dep_map, 0, 1, _RET_IP_); 422324a56e1STejun Heo return kn; 423fd7b9f7bSTejun Heo } 424fd7b9f7bSTejun Heo 425fd7b9f7bSTejun Heo /** 426c637b8acSTejun Heo * kernfs_put_active - put an active reference to kernfs_node 427324a56e1STejun Heo * @kn: kernfs_node to put an active reference to 428fd7b9f7bSTejun Heo * 429324a56e1STejun Heo * Put an active reference to @kn. This function is noop if @kn 430fd7b9f7bSTejun Heo * is NULL. 431fd7b9f7bSTejun Heo */ 432c637b8acSTejun Heo void kernfs_put_active(struct kernfs_node *kn) 433fd7b9f7bSTejun Heo { 434abd54f02STejun Heo struct kernfs_root *root = kernfs_root(kn); 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 446abd54f02STejun Heo wake_up_all(&root->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 if (kn->iattr->ia_secdata) 532adc5e8b5STejun Heo security_release_secctx(kn->iattr->ia_secdata, 533adc5e8b5STejun Heo kn->iattr->ia_secdata_len); 534adc5e8b5STejun Heo simple_xattrs_free(&kn->iattr->xattrs); 5352322392bSTejun Heo } 536adc5e8b5STejun Heo kfree(kn->iattr); 5377d35079fSShaohua Li spin_lock(&kernfs_idr_lock); 5387d35079fSShaohua Li idr_remove(&root->ino_idr, kn->ino); 5397d35079fSShaohua Li spin_unlock(&kernfs_idr_lock); 540a797bfc3STejun Heo kmem_cache_free(kernfs_node_cache, kn); 541fd7b9f7bSTejun Heo 542324a56e1STejun Heo kn = parent; 543324a56e1STejun Heo if (kn) { 544adc5e8b5STejun Heo if (atomic_dec_and_test(&kn->count)) 545fd7b9f7bSTejun Heo goto repeat; 546ba7443bcSTejun Heo } else { 547324a56e1STejun Heo /* just released the root kn, free @root too */ 5487d35079fSShaohua Li idr_destroy(&root->ino_idr); 549ba7443bcSTejun Heo kfree(root); 550ba7443bcSTejun Heo } 551fd7b9f7bSTejun Heo } 552fd7b9f7bSTejun Heo EXPORT_SYMBOL_GPL(kernfs_put); 553fd7b9f7bSTejun Heo 554c637b8acSTejun Heo static int kernfs_dop_revalidate(struct dentry *dentry, unsigned int flags) 555fd7b9f7bSTejun Heo { 556324a56e1STejun Heo struct kernfs_node *kn; 557fd7b9f7bSTejun Heo 558fd7b9f7bSTejun Heo if (flags & LOOKUP_RCU) 559fd7b9f7bSTejun Heo return -ECHILD; 560fd7b9f7bSTejun Heo 56119bbb926STejun Heo /* Always perform fresh lookup for negatives */ 5622b0143b5SDavid Howells if (d_really_is_negative(dentry)) 56319bbb926STejun Heo goto out_bad_unlocked; 56419bbb926STejun Heo 565324a56e1STejun Heo kn = dentry->d_fsdata; 566a797bfc3STejun Heo mutex_lock(&kernfs_mutex); 567fd7b9f7bSTejun Heo 56881c173cbSTejun Heo /* The kernfs node has been deactivated */ 56981c173cbSTejun Heo if (!kernfs_active(kn)) 570fd7b9f7bSTejun Heo goto out_bad; 571fd7b9f7bSTejun Heo 572c637b8acSTejun Heo /* The kernfs node has been moved? */ 573adc5e8b5STejun Heo if (dentry->d_parent->d_fsdata != kn->parent) 574fd7b9f7bSTejun Heo goto out_bad; 575fd7b9f7bSTejun Heo 576c637b8acSTejun Heo /* The kernfs node has been renamed */ 577adc5e8b5STejun Heo if (strcmp(dentry->d_name.name, kn->name) != 0) 578fd7b9f7bSTejun Heo goto out_bad; 579fd7b9f7bSTejun Heo 580c637b8acSTejun Heo /* The kernfs node has been moved to a different namespace */ 581adc5e8b5STejun Heo if (kn->parent && kernfs_ns_enabled(kn->parent) && 582c525aaddSTejun Heo kernfs_info(dentry->d_sb)->ns != kn->ns) 583fd7b9f7bSTejun Heo goto out_bad; 584fd7b9f7bSTejun Heo 585a797bfc3STejun Heo mutex_unlock(&kernfs_mutex); 586fd7b9f7bSTejun Heo return 1; 587fd7b9f7bSTejun Heo out_bad: 588a797bfc3STejun Heo mutex_unlock(&kernfs_mutex); 58919bbb926STejun Heo out_bad_unlocked: 590fd7b9f7bSTejun Heo return 0; 591fd7b9f7bSTejun Heo } 592fd7b9f7bSTejun Heo 593c637b8acSTejun Heo static void kernfs_dop_release(struct dentry *dentry) 594fd7b9f7bSTejun Heo { 595fd7b9f7bSTejun Heo kernfs_put(dentry->d_fsdata); 596fd7b9f7bSTejun Heo } 597fd7b9f7bSTejun Heo 598a797bfc3STejun Heo const struct dentry_operations kernfs_dops = { 599c637b8acSTejun Heo .d_revalidate = kernfs_dop_revalidate, 600c637b8acSTejun Heo .d_release = kernfs_dop_release, 601fd7b9f7bSTejun Heo }; 602fd7b9f7bSTejun Heo 6030c23b225STejun Heo /** 6040c23b225STejun Heo * kernfs_node_from_dentry - determine kernfs_node associated with a dentry 6050c23b225STejun Heo * @dentry: the dentry in question 6060c23b225STejun Heo * 6070c23b225STejun Heo * Return the kernfs_node associated with @dentry. If @dentry is not a 6080c23b225STejun Heo * kernfs one, %NULL is returned. 6090c23b225STejun Heo * 6100c23b225STejun Heo * While the returned kernfs_node will stay accessible as long as @dentry 6110c23b225STejun Heo * is accessible, the returned node can be in any state and the caller is 6120c23b225STejun Heo * fully responsible for determining what's accessible. 6130c23b225STejun Heo */ 6140c23b225STejun Heo struct kernfs_node *kernfs_node_from_dentry(struct dentry *dentry) 6150c23b225STejun Heo { 616f41c5934SLi Zefan if (dentry->d_sb->s_op == &kernfs_sops) 6170c23b225STejun Heo return dentry->d_fsdata; 6180c23b225STejun Heo return NULL; 6190c23b225STejun Heo } 6200c23b225STejun Heo 621db4aad20STejun Heo static struct kernfs_node *__kernfs_new_node(struct kernfs_root *root, 622db4aad20STejun Heo const char *name, umode_t mode, 623db4aad20STejun Heo unsigned flags) 624fd7b9f7bSTejun Heo { 625324a56e1STejun Heo struct kernfs_node *kn; 626bc755553STejun Heo int ret; 627fd7b9f7bSTejun Heo 628dfeb0750STejun Heo name = kstrdup_const(name, GFP_KERNEL); 629fd7b9f7bSTejun Heo if (!name) 630fd7b9f7bSTejun Heo return NULL; 631fd7b9f7bSTejun Heo 632a797bfc3STejun Heo kn = kmem_cache_zalloc(kernfs_node_cache, GFP_KERNEL); 633324a56e1STejun Heo if (!kn) 634fd7b9f7bSTejun Heo goto err_out1; 635fd7b9f7bSTejun Heo 6367d35079fSShaohua Li idr_preload(GFP_KERNEL); 6377d35079fSShaohua Li spin_lock(&kernfs_idr_lock); 6387d35079fSShaohua Li ret = idr_alloc(&root->ino_idr, kn, 1, 0, GFP_ATOMIC); 6397d35079fSShaohua Li spin_unlock(&kernfs_idr_lock); 6407d35079fSShaohua Li idr_preload_end(); 641bc755553STejun Heo if (ret < 0) 642fd7b9f7bSTejun Heo goto err_out2; 643adc5e8b5STejun Heo kn->ino = ret; 644fd7b9f7bSTejun Heo 645adc5e8b5STejun 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 653324a56e1STejun Heo return kn; 654fd7b9f7bSTejun Heo 655fd7b9f7bSTejun Heo err_out2: 656a797bfc3STejun Heo kmem_cache_free(kernfs_node_cache, kn); 657fd7b9f7bSTejun Heo err_out1: 658dfeb0750STejun Heo kfree_const(name); 659fd7b9f7bSTejun Heo return NULL; 660fd7b9f7bSTejun Heo } 661fd7b9f7bSTejun Heo 662db4aad20STejun Heo struct kernfs_node *kernfs_new_node(struct kernfs_node *parent, 663db4aad20STejun Heo const char *name, umode_t mode, 664db4aad20STejun Heo unsigned flags) 665db4aad20STejun Heo { 666db4aad20STejun Heo struct kernfs_node *kn; 667db4aad20STejun Heo 668db4aad20STejun Heo kn = __kernfs_new_node(kernfs_root(parent), name, mode, flags); 669db4aad20STejun Heo if (kn) { 670db4aad20STejun Heo kernfs_get(parent); 671db4aad20STejun Heo kn->parent = parent; 672db4aad20STejun Heo } 673db4aad20STejun Heo return kn; 674db4aad20STejun Heo } 675db4aad20STejun Heo 676fd7b9f7bSTejun Heo /** 677c637b8acSTejun Heo * kernfs_add_one - add kernfs_node to parent without warning 678324a56e1STejun Heo * @kn: kernfs_node to be added 679fd7b9f7bSTejun Heo * 680db4aad20STejun Heo * The caller must already have initialized @kn->parent. This 681db4aad20STejun Heo * function increments nlink of the parent's inode if @kn is a 682db4aad20STejun Heo * directory and link into the children list of the parent. 683fd7b9f7bSTejun Heo * 684fd7b9f7bSTejun Heo * RETURNS: 685fd7b9f7bSTejun Heo * 0 on success, -EEXIST if entry with the given name already 686fd7b9f7bSTejun Heo * exists. 687fd7b9f7bSTejun Heo */ 688988cd7afSTejun Heo int kernfs_add_one(struct kernfs_node *kn) 689fd7b9f7bSTejun Heo { 690db4aad20STejun Heo struct kernfs_node *parent = kn->parent; 691c525aaddSTejun Heo struct kernfs_iattrs *ps_iattr; 692988cd7afSTejun Heo bool has_ns; 693fd7b9f7bSTejun Heo int ret; 694fd7b9f7bSTejun Heo 695988cd7afSTejun Heo mutex_lock(&kernfs_mutex); 696988cd7afSTejun Heo 697988cd7afSTejun Heo ret = -EINVAL; 698988cd7afSTejun Heo has_ns = kernfs_ns_enabled(parent); 699988cd7afSTejun Heo if (WARN(has_ns != (bool)kn->ns, KERN_WARNING "kernfs: ns %s in '%s' for '%s'\n", 700988cd7afSTejun Heo has_ns ? "required" : "invalid", parent->name, kn->name)) 701988cd7afSTejun Heo goto out_unlock; 702fd7b9f7bSTejun Heo 703df23fc39STejun Heo if (kernfs_type(parent) != KERNFS_DIR) 704988cd7afSTejun Heo goto out_unlock; 705fd7b9f7bSTejun Heo 706988cd7afSTejun Heo ret = -ENOENT; 707ea015218SEric W. Biederman if (parent->flags & KERNFS_EMPTY_DIR) 708ea015218SEric W. Biederman goto out_unlock; 709ea015218SEric W. Biederman 710d35258efSTejun Heo if ((parent->flags & KERNFS_ACTIVATED) && !kernfs_active(parent)) 711988cd7afSTejun Heo goto out_unlock; 712798c75a0SGreg Kroah-Hartman 713c637b8acSTejun Heo kn->hash = kernfs_name_hash(kn->name, kn->ns); 714fd7b9f7bSTejun Heo 715c637b8acSTejun Heo ret = kernfs_link_sibling(kn); 716fd7b9f7bSTejun Heo if (ret) 717988cd7afSTejun Heo goto out_unlock; 718fd7b9f7bSTejun Heo 719fd7b9f7bSTejun Heo /* Update timestamps on the parent */ 720adc5e8b5STejun Heo ps_iattr = parent->iattr; 721fd7b9f7bSTejun Heo if (ps_iattr) { 722fd7b9f7bSTejun Heo struct iattr *ps_iattrs = &ps_iattr->ia_iattr; 7233a3a5fecSDeepa Dinamani ktime_get_real_ts(&ps_iattrs->ia_ctime); 7243a3a5fecSDeepa Dinamani ps_iattrs->ia_mtime = ps_iattrs->ia_ctime; 725fd7b9f7bSTejun Heo } 726fd7b9f7bSTejun Heo 727d35258efSTejun Heo mutex_unlock(&kernfs_mutex); 728d35258efSTejun Heo 729d35258efSTejun Heo /* 730d35258efSTejun Heo * Activate the new node unless CREATE_DEACTIVATED is requested. 731d35258efSTejun Heo * If not activated here, the kernfs user is responsible for 732d35258efSTejun Heo * activating the node with kernfs_activate(). A node which hasn't 733d35258efSTejun Heo * been activated is not visible to userland and its removal won't 734d35258efSTejun Heo * trigger deactivation. 735d35258efSTejun Heo */ 736d35258efSTejun Heo if (!(kernfs_root(kn)->flags & KERNFS_ROOT_CREATE_DEACTIVATED)) 737d35258efSTejun Heo kernfs_activate(kn); 738d35258efSTejun Heo return 0; 739d35258efSTejun Heo 740988cd7afSTejun Heo out_unlock: 741a797bfc3STejun Heo mutex_unlock(&kernfs_mutex); 742988cd7afSTejun Heo return ret; 743fd7b9f7bSTejun Heo } 744fd7b9f7bSTejun Heo 745fd7b9f7bSTejun Heo /** 746324a56e1STejun Heo * kernfs_find_ns - find kernfs_node with the given name 747324a56e1STejun Heo * @parent: kernfs_node to search under 748fd7b9f7bSTejun Heo * @name: name to look for 749fd7b9f7bSTejun Heo * @ns: the namespace tag to use 750fd7b9f7bSTejun Heo * 751324a56e1STejun Heo * Look for kernfs_node with name @name under @parent. Returns pointer to 752324a56e1STejun Heo * the found kernfs_node on success, %NULL on failure. 753fd7b9f7bSTejun Heo */ 754324a56e1STejun Heo static struct kernfs_node *kernfs_find_ns(struct kernfs_node *parent, 755fd7b9f7bSTejun Heo const unsigned char *name, 756fd7b9f7bSTejun Heo const void *ns) 757fd7b9f7bSTejun Heo { 758adc5e8b5STejun Heo struct rb_node *node = parent->dir.children.rb_node; 759ac9bba03STejun Heo bool has_ns = kernfs_ns_enabled(parent); 760fd7b9f7bSTejun Heo unsigned int hash; 761fd7b9f7bSTejun Heo 762a797bfc3STejun Heo lockdep_assert_held(&kernfs_mutex); 763fd7b9f7bSTejun Heo 764fd7b9f7bSTejun Heo if (has_ns != (bool)ns) { 765c637b8acSTejun Heo WARN(1, KERN_WARNING "kernfs: ns %s in '%s' for '%s'\n", 766adc5e8b5STejun Heo has_ns ? "required" : "invalid", parent->name, name); 767fd7b9f7bSTejun Heo return NULL; 768fd7b9f7bSTejun Heo } 769fd7b9f7bSTejun Heo 770c637b8acSTejun Heo hash = kernfs_name_hash(name, ns); 771fd7b9f7bSTejun Heo while (node) { 772324a56e1STejun Heo struct kernfs_node *kn; 773fd7b9f7bSTejun Heo int result; 774fd7b9f7bSTejun Heo 775324a56e1STejun Heo kn = rb_to_kn(node); 776c637b8acSTejun Heo result = kernfs_name_compare(hash, name, ns, kn); 777fd7b9f7bSTejun Heo if (result < 0) 778fd7b9f7bSTejun Heo node = node->rb_left; 779fd7b9f7bSTejun Heo else if (result > 0) 780fd7b9f7bSTejun Heo node = node->rb_right; 781fd7b9f7bSTejun Heo else 782324a56e1STejun Heo return kn; 783fd7b9f7bSTejun Heo } 784fd7b9f7bSTejun Heo return NULL; 785fd7b9f7bSTejun Heo } 786fd7b9f7bSTejun Heo 787bd96f76aSTejun Heo static struct kernfs_node *kernfs_walk_ns(struct kernfs_node *parent, 788bd96f76aSTejun Heo const unsigned char *path, 789bd96f76aSTejun Heo const void *ns) 790bd96f76aSTejun Heo { 791e56ed358STejun Heo size_t len; 792e56ed358STejun Heo char *p, *name; 793bd96f76aSTejun Heo 794bd96f76aSTejun Heo lockdep_assert_held(&kernfs_mutex); 795bd96f76aSTejun Heo 796e56ed358STejun Heo /* grab kernfs_rename_lock to piggy back on kernfs_pr_cont_buf */ 797e56ed358STejun Heo spin_lock_irq(&kernfs_rename_lock); 798e56ed358STejun Heo 799e56ed358STejun Heo len = strlcpy(kernfs_pr_cont_buf, path, sizeof(kernfs_pr_cont_buf)); 800e56ed358STejun Heo 801e56ed358STejun Heo if (len >= sizeof(kernfs_pr_cont_buf)) { 802e56ed358STejun Heo spin_unlock_irq(&kernfs_rename_lock); 803bd96f76aSTejun Heo return NULL; 804e56ed358STejun Heo } 805e56ed358STejun Heo 806e56ed358STejun Heo p = kernfs_pr_cont_buf; 807bd96f76aSTejun Heo 808bd96f76aSTejun Heo while ((name = strsep(&p, "/")) && parent) { 809bd96f76aSTejun Heo if (*name == '\0') 810bd96f76aSTejun Heo continue; 811bd96f76aSTejun Heo parent = kernfs_find_ns(parent, name, ns); 812bd96f76aSTejun Heo } 813bd96f76aSTejun Heo 814e56ed358STejun Heo spin_unlock_irq(&kernfs_rename_lock); 815e56ed358STejun Heo 816bd96f76aSTejun Heo return parent; 817bd96f76aSTejun Heo } 818bd96f76aSTejun Heo 819fd7b9f7bSTejun Heo /** 820324a56e1STejun Heo * kernfs_find_and_get_ns - find and get kernfs_node with the given name 821324a56e1STejun Heo * @parent: kernfs_node to search under 822fd7b9f7bSTejun Heo * @name: name to look for 823fd7b9f7bSTejun Heo * @ns: the namespace tag to use 824fd7b9f7bSTejun Heo * 825324a56e1STejun Heo * Look for kernfs_node with name @name under @parent and get a reference 826fd7b9f7bSTejun Heo * if found. This function may sleep and returns pointer to the found 827324a56e1STejun Heo * kernfs_node on success, %NULL on failure. 828fd7b9f7bSTejun Heo */ 829324a56e1STejun Heo struct kernfs_node *kernfs_find_and_get_ns(struct kernfs_node *parent, 830fd7b9f7bSTejun Heo const char *name, const void *ns) 831fd7b9f7bSTejun Heo { 832324a56e1STejun Heo struct kernfs_node *kn; 833fd7b9f7bSTejun Heo 834a797bfc3STejun Heo mutex_lock(&kernfs_mutex); 835324a56e1STejun Heo kn = kernfs_find_ns(parent, name, ns); 836324a56e1STejun Heo kernfs_get(kn); 837a797bfc3STejun Heo mutex_unlock(&kernfs_mutex); 838fd7b9f7bSTejun Heo 839324a56e1STejun Heo return kn; 840fd7b9f7bSTejun Heo } 841fd7b9f7bSTejun Heo EXPORT_SYMBOL_GPL(kernfs_find_and_get_ns); 842fd7b9f7bSTejun Heo 843fd7b9f7bSTejun Heo /** 844bd96f76aSTejun Heo * kernfs_walk_and_get_ns - find and get kernfs_node with the given path 845bd96f76aSTejun Heo * @parent: kernfs_node to search under 846bd96f76aSTejun Heo * @path: path to look for 847bd96f76aSTejun Heo * @ns: the namespace tag to use 848bd96f76aSTejun Heo * 849bd96f76aSTejun Heo * Look for kernfs_node with path @path under @parent and get a reference 850bd96f76aSTejun Heo * if found. This function may sleep and returns pointer to the found 851bd96f76aSTejun Heo * kernfs_node on success, %NULL on failure. 852bd96f76aSTejun Heo */ 853bd96f76aSTejun Heo struct kernfs_node *kernfs_walk_and_get_ns(struct kernfs_node *parent, 854bd96f76aSTejun Heo const char *path, const void *ns) 855bd96f76aSTejun Heo { 856bd96f76aSTejun Heo struct kernfs_node *kn; 857bd96f76aSTejun Heo 858bd96f76aSTejun Heo mutex_lock(&kernfs_mutex); 859bd96f76aSTejun Heo kn = kernfs_walk_ns(parent, path, ns); 860bd96f76aSTejun Heo kernfs_get(kn); 861bd96f76aSTejun Heo mutex_unlock(&kernfs_mutex); 862bd96f76aSTejun Heo 863bd96f76aSTejun Heo return kn; 864bd96f76aSTejun Heo } 865bd96f76aSTejun Heo 866bd96f76aSTejun Heo /** 867ba7443bcSTejun Heo * kernfs_create_root - create a new kernfs hierarchy 86890c07c89STejun Heo * @scops: optional syscall operations for the hierarchy 869d35258efSTejun Heo * @flags: KERNFS_ROOT_* flags 870ba7443bcSTejun Heo * @priv: opaque data associated with the new directory 871ba7443bcSTejun Heo * 872ba7443bcSTejun Heo * Returns the root of the new hierarchy on success, ERR_PTR() value on 873ba7443bcSTejun Heo * failure. 874ba7443bcSTejun Heo */ 87590c07c89STejun Heo struct kernfs_root *kernfs_create_root(struct kernfs_syscall_ops *scops, 876d35258efSTejun Heo unsigned int flags, void *priv) 877ba7443bcSTejun Heo { 878ba7443bcSTejun Heo struct kernfs_root *root; 879324a56e1STejun Heo struct kernfs_node *kn; 880ba7443bcSTejun Heo 881ba7443bcSTejun Heo root = kzalloc(sizeof(*root), GFP_KERNEL); 882ba7443bcSTejun Heo if (!root) 883ba7443bcSTejun Heo return ERR_PTR(-ENOMEM); 884ba7443bcSTejun Heo 8857d35079fSShaohua Li idr_init(&root->ino_idr); 8867d568a83STejun Heo INIT_LIST_HEAD(&root->supers); 887bc755553STejun Heo 888db4aad20STejun Heo kn = __kernfs_new_node(root, "", S_IFDIR | S_IRUGO | S_IXUGO, 889db4aad20STejun Heo KERNFS_DIR); 890324a56e1STejun Heo if (!kn) { 8917d35079fSShaohua Li idr_destroy(&root->ino_idr); 892ba7443bcSTejun Heo kfree(root); 893ba7443bcSTejun Heo return ERR_PTR(-ENOMEM); 894ba7443bcSTejun Heo } 895ba7443bcSTejun Heo 896324a56e1STejun Heo kn->priv = priv; 897adc5e8b5STejun Heo kn->dir.root = root; 898ba7443bcSTejun Heo 89990c07c89STejun Heo root->syscall_ops = scops; 900d35258efSTejun Heo root->flags = flags; 901324a56e1STejun Heo root->kn = kn; 902abd54f02STejun Heo init_waitqueue_head(&root->deactivate_waitq); 903ba7443bcSTejun Heo 904d35258efSTejun Heo if (!(root->flags & KERNFS_ROOT_CREATE_DEACTIVATED)) 905d35258efSTejun Heo kernfs_activate(kn); 906d35258efSTejun Heo 907ba7443bcSTejun Heo return root; 908ba7443bcSTejun Heo } 909ba7443bcSTejun Heo 910ba7443bcSTejun Heo /** 911ba7443bcSTejun Heo * kernfs_destroy_root - destroy a kernfs hierarchy 912ba7443bcSTejun Heo * @root: root of the hierarchy to destroy 913ba7443bcSTejun Heo * 914ba7443bcSTejun Heo * Destroy the hierarchy anchored at @root by removing all existing 915ba7443bcSTejun Heo * directories and destroying @root. 916ba7443bcSTejun Heo */ 917ba7443bcSTejun Heo void kernfs_destroy_root(struct kernfs_root *root) 918ba7443bcSTejun Heo { 919324a56e1STejun Heo kernfs_remove(root->kn); /* will also free @root */ 920ba7443bcSTejun Heo } 921ba7443bcSTejun Heo 922ba7443bcSTejun Heo /** 923fd7b9f7bSTejun Heo * kernfs_create_dir_ns - create a directory 924fd7b9f7bSTejun Heo * @parent: parent in which to create a new directory 925fd7b9f7bSTejun Heo * @name: name of the new directory 926bb8b9d09STejun Heo * @mode: mode of the new directory 927fd7b9f7bSTejun Heo * @priv: opaque data associated with the new directory 928fd7b9f7bSTejun Heo * @ns: optional namespace tag of the directory 929fd7b9f7bSTejun Heo * 930fd7b9f7bSTejun Heo * Returns the created node on success, ERR_PTR() value on failure. 931fd7b9f7bSTejun Heo */ 932324a56e1STejun Heo struct kernfs_node *kernfs_create_dir_ns(struct kernfs_node *parent, 933bb8b9d09STejun Heo const char *name, umode_t mode, 934bb8b9d09STejun Heo void *priv, const void *ns) 935fd7b9f7bSTejun Heo { 936324a56e1STejun Heo struct kernfs_node *kn; 937fd7b9f7bSTejun Heo int rc; 938fd7b9f7bSTejun Heo 939fd7b9f7bSTejun Heo /* allocate */ 940db4aad20STejun Heo kn = kernfs_new_node(parent, name, mode | S_IFDIR, KERNFS_DIR); 941324a56e1STejun Heo if (!kn) 942fd7b9f7bSTejun Heo return ERR_PTR(-ENOMEM); 943fd7b9f7bSTejun Heo 944adc5e8b5STejun Heo kn->dir.root = parent->dir.root; 945adc5e8b5STejun Heo kn->ns = ns; 946324a56e1STejun Heo kn->priv = priv; 947fd7b9f7bSTejun Heo 948fd7b9f7bSTejun Heo /* link in */ 949988cd7afSTejun Heo rc = kernfs_add_one(kn); 950fd7b9f7bSTejun Heo if (!rc) 951324a56e1STejun Heo return kn; 952fd7b9f7bSTejun Heo 953324a56e1STejun Heo kernfs_put(kn); 954fd7b9f7bSTejun Heo return ERR_PTR(rc); 955fd7b9f7bSTejun Heo } 956fd7b9f7bSTejun Heo 957ea015218SEric W. Biederman /** 958ea015218SEric W. Biederman * kernfs_create_empty_dir - create an always empty directory 959ea015218SEric W. Biederman * @parent: parent in which to create a new directory 960ea015218SEric W. Biederman * @name: name of the new directory 961ea015218SEric W. Biederman * 962ea015218SEric W. Biederman * Returns the created node on success, ERR_PTR() value on failure. 963ea015218SEric W. Biederman */ 964ea015218SEric W. Biederman struct kernfs_node *kernfs_create_empty_dir(struct kernfs_node *parent, 965ea015218SEric W. Biederman const char *name) 966ea015218SEric W. Biederman { 967ea015218SEric W. Biederman struct kernfs_node *kn; 968ea015218SEric W. Biederman int rc; 969ea015218SEric W. Biederman 970ea015218SEric W. Biederman /* allocate */ 971ea015218SEric W. Biederman kn = kernfs_new_node(parent, name, S_IRUGO|S_IXUGO|S_IFDIR, KERNFS_DIR); 972ea015218SEric W. Biederman if (!kn) 973ea015218SEric W. Biederman return ERR_PTR(-ENOMEM); 974ea015218SEric W. Biederman 975ea015218SEric W. Biederman kn->flags |= KERNFS_EMPTY_DIR; 976ea015218SEric W. Biederman kn->dir.root = parent->dir.root; 977ea015218SEric W. Biederman kn->ns = NULL; 978ea015218SEric W. Biederman kn->priv = NULL; 979ea015218SEric W. Biederman 980ea015218SEric W. Biederman /* link in */ 981ea015218SEric W. Biederman rc = kernfs_add_one(kn); 982ea015218SEric W. Biederman if (!rc) 983ea015218SEric W. Biederman return kn; 984ea015218SEric W. Biederman 985ea015218SEric W. Biederman kernfs_put(kn); 986ea015218SEric W. Biederman return ERR_PTR(rc); 987ea015218SEric W. Biederman } 988ea015218SEric W. Biederman 989c637b8acSTejun Heo static struct dentry *kernfs_iop_lookup(struct inode *dir, 990c637b8acSTejun Heo struct dentry *dentry, 991fd7b9f7bSTejun Heo unsigned int flags) 992fd7b9f7bSTejun Heo { 99319bbb926STejun Heo struct dentry *ret; 994324a56e1STejun Heo struct kernfs_node *parent = dentry->d_parent->d_fsdata; 995324a56e1STejun Heo struct kernfs_node *kn; 996fd7b9f7bSTejun Heo struct inode *inode; 997fd7b9f7bSTejun Heo const void *ns = NULL; 998fd7b9f7bSTejun Heo 999a797bfc3STejun Heo mutex_lock(&kernfs_mutex); 1000fd7b9f7bSTejun Heo 1001324a56e1STejun Heo if (kernfs_ns_enabled(parent)) 1002c525aaddSTejun Heo ns = kernfs_info(dir->i_sb)->ns; 1003fd7b9f7bSTejun Heo 1004324a56e1STejun Heo kn = kernfs_find_ns(parent, dentry->d_name.name, ns); 1005fd7b9f7bSTejun Heo 1006fd7b9f7bSTejun Heo /* no such entry */ 1007b9c9dad0STejun Heo if (!kn || !kernfs_active(kn)) { 100819bbb926STejun Heo ret = NULL; 1009fd7b9f7bSTejun Heo goto out_unlock; 1010fd7b9f7bSTejun Heo } 1011324a56e1STejun Heo kernfs_get(kn); 1012324a56e1STejun Heo dentry->d_fsdata = kn; 1013fd7b9f7bSTejun Heo 1014fd7b9f7bSTejun Heo /* attach dentry and inode */ 1015c637b8acSTejun Heo inode = kernfs_get_inode(dir->i_sb, kn); 1016fd7b9f7bSTejun Heo if (!inode) { 1017fd7b9f7bSTejun Heo ret = ERR_PTR(-ENOMEM); 1018fd7b9f7bSTejun Heo goto out_unlock; 1019fd7b9f7bSTejun Heo } 1020fd7b9f7bSTejun Heo 1021fd7b9f7bSTejun Heo /* instantiate and hash dentry */ 102241d28bcaSAl Viro ret = d_splice_alias(inode, dentry); 1023fd7b9f7bSTejun Heo out_unlock: 1024a797bfc3STejun Heo mutex_unlock(&kernfs_mutex); 1025fd7b9f7bSTejun Heo return ret; 1026fd7b9f7bSTejun Heo } 1027fd7b9f7bSTejun Heo 102880b9bbefSTejun Heo static int kernfs_iop_mkdir(struct inode *dir, struct dentry *dentry, 102980b9bbefSTejun Heo umode_t mode) 103080b9bbefSTejun Heo { 103180b9bbefSTejun Heo struct kernfs_node *parent = dir->i_private; 103290c07c89STejun Heo struct kernfs_syscall_ops *scops = kernfs_root(parent)->syscall_ops; 103307c7530dSTejun Heo int ret; 103480b9bbefSTejun Heo 103590c07c89STejun Heo if (!scops || !scops->mkdir) 103680b9bbefSTejun Heo return -EPERM; 103780b9bbefSTejun Heo 103807c7530dSTejun Heo if (!kernfs_get_active(parent)) 103907c7530dSTejun Heo return -ENODEV; 104007c7530dSTejun Heo 104190c07c89STejun Heo ret = scops->mkdir(parent, dentry->d_name.name, mode); 104207c7530dSTejun Heo 104307c7530dSTejun Heo kernfs_put_active(parent); 104407c7530dSTejun Heo return ret; 104580b9bbefSTejun Heo } 104680b9bbefSTejun Heo 104780b9bbefSTejun Heo static int kernfs_iop_rmdir(struct inode *dir, struct dentry *dentry) 104880b9bbefSTejun Heo { 104980b9bbefSTejun Heo struct kernfs_node *kn = dentry->d_fsdata; 105090c07c89STejun Heo struct kernfs_syscall_ops *scops = kernfs_root(kn)->syscall_ops; 105107c7530dSTejun Heo int ret; 105280b9bbefSTejun Heo 105390c07c89STejun Heo if (!scops || !scops->rmdir) 105480b9bbefSTejun Heo return -EPERM; 105580b9bbefSTejun Heo 105607c7530dSTejun Heo if (!kernfs_get_active(kn)) 105707c7530dSTejun Heo return -ENODEV; 105807c7530dSTejun Heo 105990c07c89STejun Heo ret = scops->rmdir(kn); 106007c7530dSTejun Heo 106107c7530dSTejun Heo kernfs_put_active(kn); 106207c7530dSTejun Heo return ret; 106380b9bbefSTejun Heo } 106480b9bbefSTejun Heo 106580b9bbefSTejun Heo static int kernfs_iop_rename(struct inode *old_dir, struct dentry *old_dentry, 10661cd66c93SMiklos Szeredi struct inode *new_dir, struct dentry *new_dentry, 10671cd66c93SMiklos Szeredi unsigned int flags) 106880b9bbefSTejun Heo { 106980b9bbefSTejun Heo struct kernfs_node *kn = old_dentry->d_fsdata; 107080b9bbefSTejun Heo struct kernfs_node *new_parent = new_dir->i_private; 107190c07c89STejun Heo struct kernfs_syscall_ops *scops = kernfs_root(kn)->syscall_ops; 107207c7530dSTejun Heo int ret; 107380b9bbefSTejun Heo 10741cd66c93SMiklos Szeredi if (flags) 10751cd66c93SMiklos Szeredi return -EINVAL; 10761cd66c93SMiklos Szeredi 107790c07c89STejun Heo if (!scops || !scops->rename) 107880b9bbefSTejun Heo return -EPERM; 107980b9bbefSTejun Heo 108007c7530dSTejun Heo if (!kernfs_get_active(kn)) 108107c7530dSTejun Heo return -ENODEV; 108207c7530dSTejun Heo 108307c7530dSTejun Heo if (!kernfs_get_active(new_parent)) { 108407c7530dSTejun Heo kernfs_put_active(kn); 108507c7530dSTejun Heo return -ENODEV; 108607c7530dSTejun Heo } 108707c7530dSTejun Heo 108890c07c89STejun Heo ret = scops->rename(kn, new_parent, new_dentry->d_name.name); 108907c7530dSTejun Heo 109007c7530dSTejun Heo kernfs_put_active(new_parent); 109107c7530dSTejun Heo kernfs_put_active(kn); 109207c7530dSTejun Heo return ret; 109380b9bbefSTejun Heo } 109480b9bbefSTejun Heo 1095a797bfc3STejun Heo const struct inode_operations kernfs_dir_iops = { 1096c637b8acSTejun Heo .lookup = kernfs_iop_lookup, 1097c637b8acSTejun Heo .permission = kernfs_iop_permission, 1098c637b8acSTejun Heo .setattr = kernfs_iop_setattr, 1099c637b8acSTejun Heo .getattr = kernfs_iop_getattr, 1100c637b8acSTejun Heo .listxattr = kernfs_iop_listxattr, 110180b9bbefSTejun Heo 110280b9bbefSTejun Heo .mkdir = kernfs_iop_mkdir, 110380b9bbefSTejun Heo .rmdir = kernfs_iop_rmdir, 110480b9bbefSTejun Heo .rename = kernfs_iop_rename, 1105fd7b9f7bSTejun Heo }; 1106fd7b9f7bSTejun Heo 1107c637b8acSTejun Heo static struct kernfs_node *kernfs_leftmost_descendant(struct kernfs_node *pos) 1108fd7b9f7bSTejun Heo { 1109324a56e1STejun Heo struct kernfs_node *last; 1110fd7b9f7bSTejun Heo 1111fd7b9f7bSTejun Heo while (true) { 1112fd7b9f7bSTejun Heo struct rb_node *rbn; 1113fd7b9f7bSTejun Heo 1114fd7b9f7bSTejun Heo last = pos; 1115fd7b9f7bSTejun Heo 1116df23fc39STejun Heo if (kernfs_type(pos) != KERNFS_DIR) 1117fd7b9f7bSTejun Heo break; 1118fd7b9f7bSTejun Heo 1119adc5e8b5STejun Heo rbn = rb_first(&pos->dir.children); 1120fd7b9f7bSTejun Heo if (!rbn) 1121fd7b9f7bSTejun Heo break; 1122fd7b9f7bSTejun Heo 1123324a56e1STejun Heo pos = rb_to_kn(rbn); 1124fd7b9f7bSTejun Heo } 1125fd7b9f7bSTejun Heo 1126fd7b9f7bSTejun Heo return last; 1127fd7b9f7bSTejun Heo } 1128fd7b9f7bSTejun Heo 1129fd7b9f7bSTejun Heo /** 1130c637b8acSTejun Heo * kernfs_next_descendant_post - find the next descendant for post-order walk 1131fd7b9f7bSTejun Heo * @pos: the current position (%NULL to initiate traversal) 1132324a56e1STejun Heo * @root: kernfs_node whose descendants to walk 1133fd7b9f7bSTejun Heo * 1134fd7b9f7bSTejun Heo * Find the next descendant to visit for post-order traversal of @root's 1135fd7b9f7bSTejun Heo * descendants. @root is included in the iteration and the last node to be 1136fd7b9f7bSTejun Heo * visited. 1137fd7b9f7bSTejun Heo */ 1138c637b8acSTejun Heo static struct kernfs_node *kernfs_next_descendant_post(struct kernfs_node *pos, 1139324a56e1STejun Heo struct kernfs_node *root) 1140fd7b9f7bSTejun Heo { 1141fd7b9f7bSTejun Heo struct rb_node *rbn; 1142fd7b9f7bSTejun Heo 1143a797bfc3STejun Heo lockdep_assert_held(&kernfs_mutex); 1144fd7b9f7bSTejun Heo 1145fd7b9f7bSTejun Heo /* if first iteration, visit leftmost descendant which may be root */ 1146fd7b9f7bSTejun Heo if (!pos) 1147c637b8acSTejun Heo return kernfs_leftmost_descendant(root); 1148fd7b9f7bSTejun Heo 1149fd7b9f7bSTejun Heo /* if we visited @root, we're done */ 1150fd7b9f7bSTejun Heo if (pos == root) 1151fd7b9f7bSTejun Heo return NULL; 1152fd7b9f7bSTejun Heo 1153fd7b9f7bSTejun Heo /* if there's an unvisited sibling, visit its leftmost descendant */ 1154adc5e8b5STejun Heo rbn = rb_next(&pos->rb); 1155fd7b9f7bSTejun Heo if (rbn) 1156c637b8acSTejun Heo return kernfs_leftmost_descendant(rb_to_kn(rbn)); 1157fd7b9f7bSTejun Heo 1158fd7b9f7bSTejun Heo /* no sibling left, visit parent */ 1159adc5e8b5STejun Heo return pos->parent; 1160fd7b9f7bSTejun Heo } 1161fd7b9f7bSTejun Heo 1162d35258efSTejun Heo /** 1163d35258efSTejun Heo * kernfs_activate - activate a node which started deactivated 1164d35258efSTejun Heo * @kn: kernfs_node whose subtree is to be activated 1165d35258efSTejun Heo * 1166d35258efSTejun Heo * If the root has KERNFS_ROOT_CREATE_DEACTIVATED set, a newly created node 1167d35258efSTejun Heo * needs to be explicitly activated. A node which hasn't been activated 1168d35258efSTejun Heo * isn't visible to userland and deactivation is skipped during its 1169d35258efSTejun Heo * removal. This is useful to construct atomic init sequences where 1170d35258efSTejun Heo * creation of multiple nodes should either succeed or fail atomically. 1171d35258efSTejun Heo * 1172d35258efSTejun Heo * The caller is responsible for ensuring that this function is not called 1173d35258efSTejun Heo * after kernfs_remove*() is invoked on @kn. 1174d35258efSTejun Heo */ 1175d35258efSTejun Heo void kernfs_activate(struct kernfs_node *kn) 1176d35258efSTejun Heo { 1177d35258efSTejun Heo struct kernfs_node *pos; 1178d35258efSTejun Heo 1179d35258efSTejun Heo mutex_lock(&kernfs_mutex); 1180d35258efSTejun Heo 1181d35258efSTejun Heo pos = NULL; 1182d35258efSTejun Heo while ((pos = kernfs_next_descendant_post(pos, kn))) { 1183d35258efSTejun Heo if (!pos || (pos->flags & KERNFS_ACTIVATED)) 1184d35258efSTejun Heo continue; 1185d35258efSTejun Heo 1186d35258efSTejun Heo WARN_ON_ONCE(pos->parent && RB_EMPTY_NODE(&pos->rb)); 1187d35258efSTejun Heo WARN_ON_ONCE(atomic_read(&pos->active) != KN_DEACTIVATED_BIAS); 1188d35258efSTejun Heo 1189d35258efSTejun Heo atomic_sub(KN_DEACTIVATED_BIAS, &pos->active); 1190d35258efSTejun Heo pos->flags |= KERNFS_ACTIVATED; 1191d35258efSTejun Heo } 1192d35258efSTejun Heo 1193d35258efSTejun Heo mutex_unlock(&kernfs_mutex); 1194d35258efSTejun Heo } 1195d35258efSTejun Heo 1196988cd7afSTejun Heo static void __kernfs_remove(struct kernfs_node *kn) 1197fd7b9f7bSTejun Heo { 119835beab06STejun Heo struct kernfs_node *pos; 119935beab06STejun Heo 120035beab06STejun Heo lockdep_assert_held(&kernfs_mutex); 1201fd7b9f7bSTejun Heo 12026b0afc2aSTejun Heo /* 12036b0afc2aSTejun Heo * Short-circuit if non-root @kn has already finished removal. 12046b0afc2aSTejun Heo * This is for kernfs_remove_self() which plays with active ref 12056b0afc2aSTejun Heo * after removal. 12066b0afc2aSTejun Heo */ 12076b0afc2aSTejun Heo if (!kn || (kn->parent && RB_EMPTY_NODE(&kn->rb))) 1208ce9b499cSGreg Kroah-Hartman return; 1209ce9b499cSGreg Kroah-Hartman 1210c637b8acSTejun Heo pr_debug("kernfs %s: removing\n", kn->name); 1211fd7b9f7bSTejun Heo 121281c173cbSTejun Heo /* prevent any new usage under @kn by deactivating all nodes */ 121335beab06STejun Heo pos = NULL; 121435beab06STejun Heo while ((pos = kernfs_next_descendant_post(pos, kn))) 121581c173cbSTejun Heo if (kernfs_active(pos)) 121681c173cbSTejun Heo atomic_add(KN_DEACTIVATED_BIAS, &pos->active); 121735beab06STejun Heo 121835beab06STejun Heo /* deactivate and unlink the subtree node-by-node */ 1219fd7b9f7bSTejun Heo do { 122035beab06STejun Heo pos = kernfs_leftmost_descendant(kn); 122135beab06STejun Heo 122235beab06STejun Heo /* 122381c173cbSTejun Heo * kernfs_drain() drops kernfs_mutex temporarily and @pos's 122481c173cbSTejun Heo * base ref could have been put by someone else by the time 122581c173cbSTejun Heo * the function returns. Make sure it doesn't go away 122681c173cbSTejun Heo * underneath us. 122735beab06STejun Heo */ 122835beab06STejun Heo kernfs_get(pos); 122935beab06STejun Heo 1230d35258efSTejun Heo /* 1231d35258efSTejun Heo * Drain iff @kn was activated. This avoids draining and 1232d35258efSTejun Heo * its lockdep annotations for nodes which have never been 1233d35258efSTejun Heo * activated and allows embedding kernfs_remove() in create 1234d35258efSTejun Heo * error paths without worrying about draining. 1235d35258efSTejun Heo */ 1236d35258efSTejun Heo if (kn->flags & KERNFS_ACTIVATED) 123781c173cbSTejun Heo kernfs_drain(pos); 1238d35258efSTejun Heo else 1239d35258efSTejun Heo WARN_ON_ONCE(atomic_read(&kn->active) != KN_DEACTIVATED_BIAS); 124035beab06STejun Heo 124135beab06STejun Heo /* 124235beab06STejun Heo * kernfs_unlink_sibling() succeeds once per node. Use it 124335beab06STejun Heo * to decide who's responsible for cleanups. 124435beab06STejun Heo */ 124535beab06STejun Heo if (!pos->parent || kernfs_unlink_sibling(pos)) { 124635beab06STejun Heo struct kernfs_iattrs *ps_iattr = 124735beab06STejun Heo pos->parent ? pos->parent->iattr : NULL; 124835beab06STejun Heo 124935beab06STejun Heo /* update timestamps on the parent */ 125035beab06STejun Heo if (ps_iattr) { 12513a3a5fecSDeepa Dinamani ktime_get_real_ts(&ps_iattr->ia_iattr.ia_ctime); 12523a3a5fecSDeepa Dinamani ps_iattr->ia_iattr.ia_mtime = 12533a3a5fecSDeepa Dinamani ps_iattr->ia_iattr.ia_ctime; 125435beab06STejun Heo } 125535beab06STejun Heo 1256988cd7afSTejun Heo kernfs_put(pos); 125735beab06STejun Heo } 125835beab06STejun Heo 125935beab06STejun Heo kernfs_put(pos); 126035beab06STejun Heo } while (pos != kn); 1261fd7b9f7bSTejun Heo } 1262fd7b9f7bSTejun Heo 1263fd7b9f7bSTejun Heo /** 1264324a56e1STejun Heo * kernfs_remove - remove a kernfs_node recursively 1265324a56e1STejun Heo * @kn: the kernfs_node to remove 1266fd7b9f7bSTejun Heo * 1267324a56e1STejun Heo * Remove @kn along with all its subdirectories and files. 1268fd7b9f7bSTejun Heo */ 1269324a56e1STejun Heo void kernfs_remove(struct kernfs_node *kn) 1270fd7b9f7bSTejun Heo { 1271988cd7afSTejun Heo mutex_lock(&kernfs_mutex); 1272988cd7afSTejun Heo __kernfs_remove(kn); 1273988cd7afSTejun Heo mutex_unlock(&kernfs_mutex); 1274fd7b9f7bSTejun Heo } 1275fd7b9f7bSTejun Heo 1276fd7b9f7bSTejun Heo /** 12776b0afc2aSTejun Heo * kernfs_break_active_protection - break out of active protection 12786b0afc2aSTejun Heo * @kn: the self kernfs_node 12796b0afc2aSTejun Heo * 12806b0afc2aSTejun Heo * The caller must be running off of a kernfs operation which is invoked 12816b0afc2aSTejun Heo * with an active reference - e.g. one of kernfs_ops. Each invocation of 12826b0afc2aSTejun Heo * this function must also be matched with an invocation of 12836b0afc2aSTejun Heo * kernfs_unbreak_active_protection(). 12846b0afc2aSTejun Heo * 12856b0afc2aSTejun Heo * This function releases the active reference of @kn the caller is 12866b0afc2aSTejun Heo * holding. Once this function is called, @kn may be removed at any point 12876b0afc2aSTejun Heo * and the caller is solely responsible for ensuring that the objects it 12886b0afc2aSTejun Heo * dereferences are accessible. 12896b0afc2aSTejun Heo */ 12906b0afc2aSTejun Heo void kernfs_break_active_protection(struct kernfs_node *kn) 12916b0afc2aSTejun Heo { 12926b0afc2aSTejun Heo /* 12936b0afc2aSTejun Heo * Take out ourself out of the active ref dependency chain. If 12946b0afc2aSTejun Heo * we're called without an active ref, lockdep will complain. 12956b0afc2aSTejun Heo */ 12966b0afc2aSTejun Heo kernfs_put_active(kn); 12976b0afc2aSTejun Heo } 12986b0afc2aSTejun Heo 12996b0afc2aSTejun Heo /** 13006b0afc2aSTejun Heo * kernfs_unbreak_active_protection - undo kernfs_break_active_protection() 13016b0afc2aSTejun Heo * @kn: the self kernfs_node 13026b0afc2aSTejun Heo * 13036b0afc2aSTejun Heo * If kernfs_break_active_protection() was called, this function must be 13046b0afc2aSTejun Heo * invoked before finishing the kernfs operation. Note that while this 13056b0afc2aSTejun Heo * function restores the active reference, it doesn't and can't actually 13066b0afc2aSTejun Heo * restore the active protection - @kn may already or be in the process of 13076b0afc2aSTejun Heo * being removed. Once kernfs_break_active_protection() is invoked, that 13086b0afc2aSTejun Heo * protection is irreversibly gone for the kernfs operation instance. 13096b0afc2aSTejun Heo * 13106b0afc2aSTejun Heo * While this function may be called at any point after 13116b0afc2aSTejun Heo * kernfs_break_active_protection() is invoked, its most useful location 13126b0afc2aSTejun Heo * would be right before the enclosing kernfs operation returns. 13136b0afc2aSTejun Heo */ 13146b0afc2aSTejun Heo void kernfs_unbreak_active_protection(struct kernfs_node *kn) 13156b0afc2aSTejun Heo { 13166b0afc2aSTejun Heo /* 13176b0afc2aSTejun Heo * @kn->active could be in any state; however, the increment we do 13186b0afc2aSTejun Heo * here will be undone as soon as the enclosing kernfs operation 13196b0afc2aSTejun Heo * finishes and this temporary bump can't break anything. If @kn 13206b0afc2aSTejun Heo * is alive, nothing changes. If @kn is being deactivated, the 13216b0afc2aSTejun Heo * soon-to-follow put will either finish deactivation or restore 13226b0afc2aSTejun Heo * deactivated state. If @kn is already removed, the temporary 13236b0afc2aSTejun Heo * bump is guaranteed to be gone before @kn is released. 13246b0afc2aSTejun Heo */ 13256b0afc2aSTejun Heo atomic_inc(&kn->active); 13266b0afc2aSTejun Heo if (kernfs_lockdep(kn)) 13276b0afc2aSTejun Heo rwsem_acquire(&kn->dep_map, 0, 1, _RET_IP_); 13286b0afc2aSTejun Heo } 13296b0afc2aSTejun Heo 13306b0afc2aSTejun Heo /** 13316b0afc2aSTejun Heo * kernfs_remove_self - remove a kernfs_node from its own method 13326b0afc2aSTejun Heo * @kn: the self kernfs_node to remove 13336b0afc2aSTejun Heo * 13346b0afc2aSTejun Heo * The caller must be running off of a kernfs operation which is invoked 13356b0afc2aSTejun Heo * with an active reference - e.g. one of kernfs_ops. This can be used to 13366b0afc2aSTejun Heo * implement a file operation which deletes itself. 13376b0afc2aSTejun Heo * 13386b0afc2aSTejun Heo * For example, the "delete" file for a sysfs device directory can be 13396b0afc2aSTejun Heo * implemented by invoking kernfs_remove_self() on the "delete" file 13406b0afc2aSTejun Heo * itself. This function breaks the circular dependency of trying to 13416b0afc2aSTejun Heo * deactivate self while holding an active ref itself. It isn't necessary 13426b0afc2aSTejun Heo * to modify the usual removal path to use kernfs_remove_self(). The 13436b0afc2aSTejun Heo * "delete" implementation can simply invoke kernfs_remove_self() on self 13446b0afc2aSTejun Heo * before proceeding with the usual removal path. kernfs will ignore later 13456b0afc2aSTejun Heo * kernfs_remove() on self. 13466b0afc2aSTejun Heo * 13476b0afc2aSTejun Heo * kernfs_remove_self() can be called multiple times concurrently on the 13486b0afc2aSTejun Heo * same kernfs_node. Only the first one actually performs removal and 13496b0afc2aSTejun Heo * returns %true. All others will wait until the kernfs operation which 13506b0afc2aSTejun Heo * won self-removal finishes and return %false. Note that the losers wait 13516b0afc2aSTejun Heo * for the completion of not only the winning kernfs_remove_self() but also 13526b0afc2aSTejun Heo * the whole kernfs_ops which won the arbitration. This can be used to 13536b0afc2aSTejun Heo * guarantee, for example, all concurrent writes to a "delete" file to 13546b0afc2aSTejun Heo * finish only after the whole operation is complete. 13556b0afc2aSTejun Heo */ 13566b0afc2aSTejun Heo bool kernfs_remove_self(struct kernfs_node *kn) 13576b0afc2aSTejun Heo { 13586b0afc2aSTejun Heo bool ret; 13596b0afc2aSTejun Heo 13606b0afc2aSTejun Heo mutex_lock(&kernfs_mutex); 13616b0afc2aSTejun Heo kernfs_break_active_protection(kn); 13626b0afc2aSTejun Heo 13636b0afc2aSTejun Heo /* 13646b0afc2aSTejun Heo * SUICIDAL is used to arbitrate among competing invocations. Only 13656b0afc2aSTejun Heo * the first one will actually perform removal. When the removal 13666b0afc2aSTejun Heo * is complete, SUICIDED is set and the active ref is restored 13676b0afc2aSTejun Heo * while holding kernfs_mutex. The ones which lost arbitration 13686b0afc2aSTejun Heo * waits for SUICDED && drained which can happen only after the 13696b0afc2aSTejun Heo * enclosing kernfs operation which executed the winning instance 13706b0afc2aSTejun Heo * of kernfs_remove_self() finished. 13716b0afc2aSTejun Heo */ 13726b0afc2aSTejun Heo if (!(kn->flags & KERNFS_SUICIDAL)) { 13736b0afc2aSTejun Heo kn->flags |= KERNFS_SUICIDAL; 13746b0afc2aSTejun Heo __kernfs_remove(kn); 13756b0afc2aSTejun Heo kn->flags |= KERNFS_SUICIDED; 13766b0afc2aSTejun Heo ret = true; 13776b0afc2aSTejun Heo } else { 13786b0afc2aSTejun Heo wait_queue_head_t *waitq = &kernfs_root(kn)->deactivate_waitq; 13796b0afc2aSTejun Heo DEFINE_WAIT(wait); 13806b0afc2aSTejun Heo 13816b0afc2aSTejun Heo while (true) { 13826b0afc2aSTejun Heo prepare_to_wait(waitq, &wait, TASK_UNINTERRUPTIBLE); 13836b0afc2aSTejun Heo 13846b0afc2aSTejun Heo if ((kn->flags & KERNFS_SUICIDED) && 13856b0afc2aSTejun Heo atomic_read(&kn->active) == KN_DEACTIVATED_BIAS) 13866b0afc2aSTejun Heo break; 13876b0afc2aSTejun Heo 13886b0afc2aSTejun Heo mutex_unlock(&kernfs_mutex); 13896b0afc2aSTejun Heo schedule(); 13906b0afc2aSTejun Heo mutex_lock(&kernfs_mutex); 13916b0afc2aSTejun Heo } 13926b0afc2aSTejun Heo finish_wait(waitq, &wait); 13936b0afc2aSTejun Heo WARN_ON_ONCE(!RB_EMPTY_NODE(&kn->rb)); 13946b0afc2aSTejun Heo ret = false; 13956b0afc2aSTejun Heo } 13966b0afc2aSTejun Heo 13976b0afc2aSTejun Heo /* 13986b0afc2aSTejun Heo * This must be done while holding kernfs_mutex; otherwise, waiting 13996b0afc2aSTejun Heo * for SUICIDED && deactivated could finish prematurely. 14006b0afc2aSTejun Heo */ 14016b0afc2aSTejun Heo kernfs_unbreak_active_protection(kn); 14026b0afc2aSTejun Heo 14036b0afc2aSTejun Heo mutex_unlock(&kernfs_mutex); 14046b0afc2aSTejun Heo return ret; 14056b0afc2aSTejun Heo } 14066b0afc2aSTejun Heo 14076b0afc2aSTejun Heo /** 1408324a56e1STejun Heo * kernfs_remove_by_name_ns - find a kernfs_node by name and remove it 1409324a56e1STejun Heo * @parent: parent of the target 1410324a56e1STejun Heo * @name: name of the kernfs_node to remove 1411324a56e1STejun Heo * @ns: namespace tag of the kernfs_node to remove 1412fd7b9f7bSTejun Heo * 1413324a56e1STejun Heo * Look for the kernfs_node with @name and @ns under @parent and remove it. 1414324a56e1STejun Heo * Returns 0 on success, -ENOENT if such entry doesn't exist. 1415fd7b9f7bSTejun Heo */ 1416324a56e1STejun Heo int kernfs_remove_by_name_ns(struct kernfs_node *parent, const char *name, 1417fd7b9f7bSTejun Heo const void *ns) 1418fd7b9f7bSTejun Heo { 1419324a56e1STejun Heo struct kernfs_node *kn; 1420fd7b9f7bSTejun Heo 1421324a56e1STejun Heo if (!parent) { 1422c637b8acSTejun Heo WARN(1, KERN_WARNING "kernfs: can not remove '%s', no directory\n", 1423fd7b9f7bSTejun Heo name); 1424fd7b9f7bSTejun Heo return -ENOENT; 1425fd7b9f7bSTejun Heo } 1426fd7b9f7bSTejun Heo 1427988cd7afSTejun Heo mutex_lock(&kernfs_mutex); 1428fd7b9f7bSTejun Heo 1429324a56e1STejun Heo kn = kernfs_find_ns(parent, name, ns); 1430324a56e1STejun Heo if (kn) 1431988cd7afSTejun Heo __kernfs_remove(kn); 1432fd7b9f7bSTejun Heo 1433988cd7afSTejun Heo mutex_unlock(&kernfs_mutex); 1434fd7b9f7bSTejun Heo 1435324a56e1STejun Heo if (kn) 1436fd7b9f7bSTejun Heo return 0; 1437fd7b9f7bSTejun Heo else 1438fd7b9f7bSTejun Heo return -ENOENT; 1439fd7b9f7bSTejun Heo } 1440fd7b9f7bSTejun Heo 1441fd7b9f7bSTejun Heo /** 1442fd7b9f7bSTejun Heo * kernfs_rename_ns - move and rename a kernfs_node 1443324a56e1STejun Heo * @kn: target node 1444fd7b9f7bSTejun Heo * @new_parent: new parent to put @sd under 1445fd7b9f7bSTejun Heo * @new_name: new name 1446fd7b9f7bSTejun Heo * @new_ns: new namespace tag 1447fd7b9f7bSTejun Heo */ 1448324a56e1STejun Heo int kernfs_rename_ns(struct kernfs_node *kn, struct kernfs_node *new_parent, 1449fd7b9f7bSTejun Heo const char *new_name, const void *new_ns) 1450fd7b9f7bSTejun Heo { 14513eef34adSTejun Heo struct kernfs_node *old_parent; 14523eef34adSTejun Heo const char *old_name = NULL; 1453fd7b9f7bSTejun Heo int error; 1454fd7b9f7bSTejun Heo 14553eef34adSTejun Heo /* can't move or rename root */ 14563eef34adSTejun Heo if (!kn->parent) 14573eef34adSTejun Heo return -EINVAL; 14583eef34adSTejun Heo 1459ae34372eSTejun Heo mutex_lock(&kernfs_mutex); 1460d0ae3d43STejun Heo 1461798c75a0SGreg Kroah-Hartman error = -ENOENT; 1462ea015218SEric W. Biederman if (!kernfs_active(kn) || !kernfs_active(new_parent) || 1463ea015218SEric W. Biederman (new_parent->flags & KERNFS_EMPTY_DIR)) 1464798c75a0SGreg Kroah-Hartman goto out; 1465798c75a0SGreg Kroah-Hartman 1466fd7b9f7bSTejun Heo error = 0; 1467adc5e8b5STejun Heo if ((kn->parent == new_parent) && (kn->ns == new_ns) && 1468adc5e8b5STejun Heo (strcmp(kn->name, new_name) == 0)) 1469798c75a0SGreg Kroah-Hartman goto out; /* nothing to rename */ 1470fd7b9f7bSTejun Heo 1471fd7b9f7bSTejun Heo error = -EEXIST; 1472fd7b9f7bSTejun Heo if (kernfs_find_ns(new_parent, new_name, new_ns)) 1473798c75a0SGreg Kroah-Hartman goto out; 1474fd7b9f7bSTejun Heo 1475324a56e1STejun Heo /* rename kernfs_node */ 1476adc5e8b5STejun Heo if (strcmp(kn->name, new_name) != 0) { 1477fd7b9f7bSTejun Heo error = -ENOMEM; 147875287a67SAndrzej Hajda new_name = kstrdup_const(new_name, GFP_KERNEL); 1479fd7b9f7bSTejun Heo if (!new_name) 1480798c75a0SGreg Kroah-Hartman goto out; 14813eef34adSTejun Heo } else { 14823eef34adSTejun Heo new_name = NULL; 1483fd7b9f7bSTejun Heo } 1484fd7b9f7bSTejun Heo 1485fd7b9f7bSTejun Heo /* 1486fd7b9f7bSTejun Heo * Move to the appropriate place in the appropriate directories rbtree. 1487fd7b9f7bSTejun Heo */ 1488c637b8acSTejun Heo kernfs_unlink_sibling(kn); 1489fd7b9f7bSTejun Heo kernfs_get(new_parent); 14903eef34adSTejun Heo 14913eef34adSTejun Heo /* rename_lock protects ->parent and ->name accessors */ 14923eef34adSTejun Heo spin_lock_irq(&kernfs_rename_lock); 14933eef34adSTejun Heo 14943eef34adSTejun Heo old_parent = kn->parent; 1495adc5e8b5STejun Heo kn->parent = new_parent; 14963eef34adSTejun Heo 14973eef34adSTejun Heo kn->ns = new_ns; 14983eef34adSTejun Heo if (new_name) { 14993eef34adSTejun Heo old_name = kn->name; 15003eef34adSTejun Heo kn->name = new_name; 15013eef34adSTejun Heo } 15023eef34adSTejun Heo 15033eef34adSTejun Heo spin_unlock_irq(&kernfs_rename_lock); 15043eef34adSTejun Heo 15059561a896STejun Heo kn->hash = kernfs_name_hash(kn->name, kn->ns); 1506c637b8acSTejun Heo kernfs_link_sibling(kn); 1507fd7b9f7bSTejun Heo 15083eef34adSTejun Heo kernfs_put(old_parent); 150975287a67SAndrzej Hajda kfree_const(old_name); 15103eef34adSTejun Heo 1511fd7b9f7bSTejun Heo error = 0; 1512ae34372eSTejun Heo out: 1513798c75a0SGreg Kroah-Hartman mutex_unlock(&kernfs_mutex); 1514fd7b9f7bSTejun Heo return error; 1515fd7b9f7bSTejun Heo } 1516fd7b9f7bSTejun Heo 1517fd7b9f7bSTejun Heo /* Relationship between s_mode and the DT_xxx types */ 1518324a56e1STejun Heo static inline unsigned char dt_type(struct kernfs_node *kn) 1519fd7b9f7bSTejun Heo { 1520adc5e8b5STejun Heo return (kn->mode >> 12) & 15; 1521fd7b9f7bSTejun Heo } 1522fd7b9f7bSTejun Heo 1523c637b8acSTejun Heo static int kernfs_dir_fop_release(struct inode *inode, struct file *filp) 1524fd7b9f7bSTejun Heo { 1525fd7b9f7bSTejun Heo kernfs_put(filp->private_data); 1526fd7b9f7bSTejun Heo return 0; 1527fd7b9f7bSTejun Heo } 1528fd7b9f7bSTejun Heo 1529c637b8acSTejun Heo static struct kernfs_node *kernfs_dir_pos(const void *ns, 1530324a56e1STejun Heo struct kernfs_node *parent, loff_t hash, struct kernfs_node *pos) 1531fd7b9f7bSTejun Heo { 1532fd7b9f7bSTejun Heo if (pos) { 153381c173cbSTejun Heo int valid = kernfs_active(pos) && 1534798c75a0SGreg Kroah-Hartman pos->parent == parent && hash == pos->hash; 1535fd7b9f7bSTejun Heo kernfs_put(pos); 1536fd7b9f7bSTejun Heo if (!valid) 1537fd7b9f7bSTejun Heo pos = NULL; 1538fd7b9f7bSTejun Heo } 1539fd7b9f7bSTejun Heo if (!pos && (hash > 1) && (hash < INT_MAX)) { 1540adc5e8b5STejun Heo struct rb_node *node = parent->dir.children.rb_node; 1541fd7b9f7bSTejun Heo while (node) { 1542324a56e1STejun Heo pos = rb_to_kn(node); 1543fd7b9f7bSTejun Heo 1544adc5e8b5STejun Heo if (hash < pos->hash) 1545fd7b9f7bSTejun Heo node = node->rb_left; 1546adc5e8b5STejun Heo else if (hash > pos->hash) 1547fd7b9f7bSTejun Heo node = node->rb_right; 1548fd7b9f7bSTejun Heo else 1549fd7b9f7bSTejun Heo break; 1550fd7b9f7bSTejun Heo } 1551fd7b9f7bSTejun Heo } 1552b9c9dad0STejun Heo /* Skip over entries which are dying/dead or in the wrong namespace */ 1553b9c9dad0STejun Heo while (pos && (!kernfs_active(pos) || pos->ns != ns)) { 1554adc5e8b5STejun Heo struct rb_node *node = rb_next(&pos->rb); 1555fd7b9f7bSTejun Heo if (!node) 1556fd7b9f7bSTejun Heo pos = NULL; 1557fd7b9f7bSTejun Heo else 1558324a56e1STejun Heo pos = rb_to_kn(node); 1559fd7b9f7bSTejun Heo } 1560fd7b9f7bSTejun Heo return pos; 1561fd7b9f7bSTejun Heo } 1562fd7b9f7bSTejun Heo 1563c637b8acSTejun Heo static struct kernfs_node *kernfs_dir_next_pos(const void *ns, 1564324a56e1STejun Heo struct kernfs_node *parent, ino_t ino, struct kernfs_node *pos) 1565fd7b9f7bSTejun Heo { 1566c637b8acSTejun Heo pos = kernfs_dir_pos(ns, parent, ino, pos); 1567b9c9dad0STejun Heo if (pos) { 1568fd7b9f7bSTejun Heo do { 1569adc5e8b5STejun Heo struct rb_node *node = rb_next(&pos->rb); 1570fd7b9f7bSTejun Heo if (!node) 1571fd7b9f7bSTejun Heo pos = NULL; 1572fd7b9f7bSTejun Heo else 1573324a56e1STejun Heo pos = rb_to_kn(node); 1574b9c9dad0STejun Heo } while (pos && (!kernfs_active(pos) || pos->ns != ns)); 1575b9c9dad0STejun Heo } 1576fd7b9f7bSTejun Heo return pos; 1577fd7b9f7bSTejun Heo } 1578fd7b9f7bSTejun Heo 1579c637b8acSTejun Heo static int kernfs_fop_readdir(struct file *file, struct dir_context *ctx) 1580fd7b9f7bSTejun Heo { 1581fd7b9f7bSTejun Heo struct dentry *dentry = file->f_path.dentry; 1582324a56e1STejun Heo struct kernfs_node *parent = dentry->d_fsdata; 1583324a56e1STejun Heo struct kernfs_node *pos = file->private_data; 1584fd7b9f7bSTejun Heo const void *ns = NULL; 1585fd7b9f7bSTejun Heo 1586fd7b9f7bSTejun Heo if (!dir_emit_dots(file, ctx)) 1587fd7b9f7bSTejun Heo return 0; 1588a797bfc3STejun Heo mutex_lock(&kernfs_mutex); 1589fd7b9f7bSTejun Heo 1590324a56e1STejun Heo if (kernfs_ns_enabled(parent)) 1591c525aaddSTejun Heo ns = kernfs_info(dentry->d_sb)->ns; 1592fd7b9f7bSTejun Heo 1593c637b8acSTejun Heo for (pos = kernfs_dir_pos(ns, parent, ctx->pos, pos); 1594fd7b9f7bSTejun Heo pos; 1595c637b8acSTejun Heo pos = kernfs_dir_next_pos(ns, parent, ctx->pos, pos)) { 1596adc5e8b5STejun Heo const char *name = pos->name; 1597fd7b9f7bSTejun Heo unsigned int type = dt_type(pos); 1598fd7b9f7bSTejun Heo int len = strlen(name); 1599adc5e8b5STejun Heo ino_t ino = pos->ino; 1600fd7b9f7bSTejun Heo 1601adc5e8b5STejun Heo ctx->pos = pos->hash; 1602fd7b9f7bSTejun Heo file->private_data = pos; 1603fd7b9f7bSTejun Heo kernfs_get(pos); 1604fd7b9f7bSTejun Heo 1605a797bfc3STejun Heo mutex_unlock(&kernfs_mutex); 1606fd7b9f7bSTejun Heo if (!dir_emit(ctx, name, len, ino, type)) 1607fd7b9f7bSTejun Heo return 0; 1608a797bfc3STejun Heo mutex_lock(&kernfs_mutex); 1609fd7b9f7bSTejun Heo } 1610a797bfc3STejun Heo mutex_unlock(&kernfs_mutex); 1611fd7b9f7bSTejun Heo file->private_data = NULL; 1612fd7b9f7bSTejun Heo ctx->pos = INT_MAX; 1613fd7b9f7bSTejun Heo return 0; 1614fd7b9f7bSTejun Heo } 1615fd7b9f7bSTejun Heo 1616a797bfc3STejun Heo const struct file_operations kernfs_dir_fops = { 1617fd7b9f7bSTejun Heo .read = generic_read_dir, 16188cb0d2c1SAl Viro .iterate_shared = kernfs_fop_readdir, 1619c637b8acSTejun Heo .release = kernfs_dir_fop_release, 16208cb0d2c1SAl Viro .llseek = generic_file_llseek, 1621fd7b9f7bSTejun Heo }; 1622