^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1) // SPDX-License-Identifier: GPL-2.0-only
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3) * fs/kernfs/dir.c - kernfs directory implementation
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 4) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 5) * Copyright (c) 2001-3 Patrick Mochel
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 6) * Copyright (c) 2007 SUSE Linux Products GmbH
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 7) * Copyright (c) 2007, 2013 Tejun Heo <tj@kernel.org>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 8) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 9)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 10) #include <linux/sched.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 11) #include <linux/fs.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 12) #include <linux/namei.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 13) #include <linux/idr.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 14) #include <linux/slab.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 15) #include <linux/security.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 16) #include <linux/hash.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 17)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 18) #include "kernfs-internal.h"
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 19)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 20) DEFINE_MUTEX(kernfs_mutex);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 21) static DEFINE_SPINLOCK(kernfs_rename_lock); /* kn->parent and ->name */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 22) static char kernfs_pr_cont_buf[PATH_MAX]; /* protected by rename_lock */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 23) static DEFINE_SPINLOCK(kernfs_idr_lock); /* root->ino_idr */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 24)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 25) #define rb_to_kn(X) rb_entry((X), struct kernfs_node, rb)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 26)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 27) static bool kernfs_active(struct kernfs_node *kn)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 28) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 29) lockdep_assert_held(&kernfs_mutex);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 30) return atomic_read(&kn->active) >= 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 31) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 32)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 33) static bool kernfs_lockdep(struct kernfs_node *kn)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 34) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 35) #ifdef CONFIG_DEBUG_LOCK_ALLOC
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 36) return kn->flags & KERNFS_LOCKDEP;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 37) #else
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 38) return false;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 39) #endif
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 40) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 41)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 42) static int kernfs_name_locked(struct kernfs_node *kn, char *buf, size_t buflen)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 43) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 44) if (!kn)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 45) return strlcpy(buf, "(null)", buflen);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 46)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 47) return strlcpy(buf, kn->parent ? kn->name : "/", buflen);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 48) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 49)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 50) /* kernfs_node_depth - compute depth from @from to @to */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 51) static size_t kernfs_depth(struct kernfs_node *from, struct kernfs_node *to)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 52) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 53) size_t depth = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 54)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 55) while (to->parent && to != from) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 56) depth++;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 57) to = to->parent;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 58) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 59) return depth;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 60) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 61)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 62) static struct kernfs_node *kernfs_common_ancestor(struct kernfs_node *a,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 63) struct kernfs_node *b)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 64) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 65) size_t da, db;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 66) struct kernfs_root *ra = kernfs_root(a), *rb = kernfs_root(b);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 67)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 68) if (ra != rb)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 69) return NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 70)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 71) da = kernfs_depth(ra->kn, a);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 72) db = kernfs_depth(rb->kn, b);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 73)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 74) while (da > db) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 75) a = a->parent;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 76) da--;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 77) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 78) while (db > da) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 79) b = b->parent;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 80) db--;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 81) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 82)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 83) /* worst case b and a will be the same at root */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 84) while (b != a) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 85) b = b->parent;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 86) a = a->parent;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 87) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 88)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 89) return a;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 90) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 91)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 92) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 93) * kernfs_path_from_node_locked - find a pseudo-absolute path to @kn_to,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 94) * where kn_from is treated as root of the path.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 95) * @kn_from: kernfs node which should be treated as root for the path
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 96) * @kn_to: kernfs node to which path is needed
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 97) * @buf: buffer to copy the path into
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 98) * @buflen: size of @buf
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 99) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 100) * We need to handle couple of scenarios here:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 101) * [1] when @kn_from is an ancestor of @kn_to at some level
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 102) * kn_from: /n1/n2/n3
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 103) * kn_to: /n1/n2/n3/n4/n5
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 104) * result: /n4/n5
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 105) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 106) * [2] when @kn_from is on a different hierarchy and we need to find common
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 107) * ancestor between @kn_from and @kn_to.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 108) * kn_from: /n1/n2/n3/n4
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 109) * kn_to: /n1/n2/n5
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 110) * result: /../../n5
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 111) * OR
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 112) * kn_from: /n1/n2/n3/n4/n5 [depth=5]
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 113) * kn_to: /n1/n2/n3 [depth=3]
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 114) * result: /../..
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 115) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 116) * [3] when @kn_to is NULL result will be "(null)"
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 117) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 118) * Returns the length of the full path. If the full length is equal to or
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 119) * greater than @buflen, @buf contains the truncated path with the trailing
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 120) * '\0'. On error, -errno is returned.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 121) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 122) static int kernfs_path_from_node_locked(struct kernfs_node *kn_to,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 123) struct kernfs_node *kn_from,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 124) char *buf, size_t buflen)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 125) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 126) struct kernfs_node *kn, *common;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 127) const char parent_str[] = "/..";
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 128) size_t depth_from, depth_to, len = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 129) int i, j;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 130)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 131) if (!kn_to)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 132) return strlcpy(buf, "(null)", buflen);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 133)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 134) if (!kn_from)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 135) kn_from = kernfs_root(kn_to)->kn;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 136)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 137) if (kn_from == kn_to)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 138) return strlcpy(buf, "/", buflen);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 139)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 140) if (!buf)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 141) return -EINVAL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 142)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 143) common = kernfs_common_ancestor(kn_from, kn_to);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 144) if (WARN_ON(!common))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 145) return -EINVAL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 146)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 147) depth_to = kernfs_depth(common, kn_to);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 148) depth_from = kernfs_depth(common, kn_from);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 149)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 150) buf[0] = '\0';
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 151)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 152) for (i = 0; i < depth_from; i++)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 153) len += strlcpy(buf + len, parent_str,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 154) len < buflen ? buflen - len : 0);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 155)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 156) /* Calculate how many bytes we need for the rest */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 157) for (i = depth_to - 1; i >= 0; i--) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 158) for (kn = kn_to, j = 0; j < i; j++)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 159) kn = kn->parent;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 160) len += strlcpy(buf + len, "/",
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 161) len < buflen ? buflen - len : 0);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 162) len += strlcpy(buf + len, kn->name,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 163) len < buflen ? buflen - len : 0);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 164) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 165)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 166) return len;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 167) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 168)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 169) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 170) * kernfs_name - obtain the name of a given node
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 171) * @kn: kernfs_node of interest
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 172) * @buf: buffer to copy @kn's name into
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 173) * @buflen: size of @buf
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 174) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 175) * Copies the name of @kn into @buf of @buflen bytes. The behavior is
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 176) * similar to strlcpy(). It returns the length of @kn's name and if @buf
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 177) * isn't long enough, it's filled upto @buflen-1 and nul terminated.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 178) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 179) * Fills buffer with "(null)" if @kn is NULL.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 180) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 181) * This function can be called from any context.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 182) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 183) int kernfs_name(struct kernfs_node *kn, char *buf, size_t buflen)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 184) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 185) unsigned long flags;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 186) int ret;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 187)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 188) spin_lock_irqsave(&kernfs_rename_lock, flags);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 189) ret = kernfs_name_locked(kn, buf, buflen);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 190) spin_unlock_irqrestore(&kernfs_rename_lock, flags);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 191) return ret;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 192) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 193)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 194) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 195) * kernfs_path_from_node - build path of node @to relative to @from.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 196) * @from: parent kernfs_node relative to which we need to build the path
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 197) * @to: kernfs_node of interest
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 198) * @buf: buffer to copy @to's path into
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 199) * @buflen: size of @buf
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 200) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 201) * Builds @to's path relative to @from in @buf. @from and @to must
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 202) * be on the same kernfs-root. If @from is not parent of @to, then a relative
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 203) * path (which includes '..'s) as needed to reach from @from to @to is
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 204) * returned.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 205) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 206) * Returns the length of the full path. If the full length is equal to or
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 207) * greater than @buflen, @buf contains the truncated path with the trailing
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 208) * '\0'. On error, -errno is returned.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 209) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 210) int kernfs_path_from_node(struct kernfs_node *to, struct kernfs_node *from,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 211) char *buf, size_t buflen)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 212) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 213) unsigned long flags;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 214) int ret;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 215)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 216) spin_lock_irqsave(&kernfs_rename_lock, flags);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 217) ret = kernfs_path_from_node_locked(to, from, buf, buflen);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 218) spin_unlock_irqrestore(&kernfs_rename_lock, flags);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 219) return ret;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 220) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 221) EXPORT_SYMBOL_GPL(kernfs_path_from_node);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 222)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 223) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 224) * pr_cont_kernfs_name - pr_cont name of a kernfs_node
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 225) * @kn: kernfs_node of interest
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 226) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 227) * This function can be called from any context.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 228) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 229) void pr_cont_kernfs_name(struct kernfs_node *kn)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 230) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 231) unsigned long flags;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 232)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 233) spin_lock_irqsave(&kernfs_rename_lock, flags);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 234)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 235) kernfs_name_locked(kn, kernfs_pr_cont_buf, sizeof(kernfs_pr_cont_buf));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 236) pr_cont("%s", kernfs_pr_cont_buf);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 237)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 238) spin_unlock_irqrestore(&kernfs_rename_lock, flags);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 239) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 240)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 241) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 242) * pr_cont_kernfs_path - pr_cont path of a kernfs_node
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 243) * @kn: kernfs_node of interest
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 244) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 245) * This function can be called from any context.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 246) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 247) void pr_cont_kernfs_path(struct kernfs_node *kn)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 248) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 249) unsigned long flags;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 250) int sz;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 251)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 252) spin_lock_irqsave(&kernfs_rename_lock, flags);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 253)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 254) sz = kernfs_path_from_node_locked(kn, NULL, kernfs_pr_cont_buf,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 255) sizeof(kernfs_pr_cont_buf));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 256) if (sz < 0) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 257) pr_cont("(error)");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 258) goto out;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 259) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 260)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 261) if (sz >= sizeof(kernfs_pr_cont_buf)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 262) pr_cont("(name too long)");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 263) goto out;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 264) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 265)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 266) pr_cont("%s", kernfs_pr_cont_buf);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 267)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 268) out:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 269) spin_unlock_irqrestore(&kernfs_rename_lock, flags);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 270) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 271)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 272) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 273) * kernfs_get_parent - determine the parent node and pin it
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 274) * @kn: kernfs_node of interest
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 275) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 276) * Determines @kn's parent, pins and returns it. This function can be
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 277) * called from any context.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 278) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 279) struct kernfs_node *kernfs_get_parent(struct kernfs_node *kn)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 280) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 281) struct kernfs_node *parent;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 282) unsigned long flags;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 283)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 284) spin_lock_irqsave(&kernfs_rename_lock, flags);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 285) parent = kn->parent;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 286) kernfs_get(parent);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 287) spin_unlock_irqrestore(&kernfs_rename_lock, flags);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 288)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 289) return parent;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 290) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 291)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 292) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 293) * kernfs_name_hash
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 294) * @name: Null terminated string to hash
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 295) * @ns: Namespace tag to hash
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 296) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 297) * Returns 31 bit hash of ns + name (so it fits in an off_t )
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 298) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 299) static unsigned int kernfs_name_hash(const char *name, const void *ns)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 300) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 301) unsigned long hash = init_name_hash(ns);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 302) unsigned int len = strlen(name);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 303) while (len--)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 304) hash = partial_name_hash(*name++, hash);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 305) hash = end_name_hash(hash);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 306) hash &= 0x7fffffffU;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 307) /* Reserve hash numbers 0, 1 and INT_MAX for magic directory entries */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 308) if (hash < 2)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 309) hash += 2;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 310) if (hash >= INT_MAX)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 311) hash = INT_MAX - 1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 312) return hash;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 313) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 314)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 315) static int kernfs_name_compare(unsigned int hash, const char *name,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 316) const void *ns, const struct kernfs_node *kn)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 317) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 318) if (hash < kn->hash)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 319) return -1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 320) if (hash > kn->hash)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 321) return 1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 322) if (ns < kn->ns)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 323) return -1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 324) if (ns > kn->ns)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 325) return 1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 326) return strcmp(name, kn->name);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 327) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 328)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 329) static int kernfs_sd_compare(const struct kernfs_node *left,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 330) const struct kernfs_node *right)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 331) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 332) return kernfs_name_compare(left->hash, left->name, left->ns, right);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 333) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 334)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 335) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 336) * kernfs_link_sibling - link kernfs_node into sibling rbtree
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 337) * @kn: kernfs_node of interest
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 338) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 339) * Link @kn into its sibling rbtree which starts from
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 340) * @kn->parent->dir.children.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 341) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 342) * Locking:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 343) * mutex_lock(kernfs_mutex)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 344) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 345) * RETURNS:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 346) * 0 on susccess -EEXIST on failure.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 347) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 348) static int kernfs_link_sibling(struct kernfs_node *kn)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 349) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 350) struct rb_node **node = &kn->parent->dir.children.rb_node;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 351) struct rb_node *parent = NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 352)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 353) while (*node) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 354) struct kernfs_node *pos;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 355) int result;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 356)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 357) pos = rb_to_kn(*node);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 358) parent = *node;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 359) result = kernfs_sd_compare(kn, pos);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 360) if (result < 0)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 361) node = &pos->rb.rb_left;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 362) else if (result > 0)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 363) node = &pos->rb.rb_right;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 364) else
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 365) return -EEXIST;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 366) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 367)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 368) /* add new node and rebalance the tree */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 369) rb_link_node(&kn->rb, parent, node);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 370) rb_insert_color(&kn->rb, &kn->parent->dir.children);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 371)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 372) /* successfully added, account subdir number */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 373) if (kernfs_type(kn) == KERNFS_DIR)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 374) kn->parent->dir.subdirs++;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 375)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 376) return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 377) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 378)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 379) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 380) * kernfs_unlink_sibling - unlink kernfs_node from sibling rbtree
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 381) * @kn: kernfs_node of interest
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 382) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 383) * Try to unlink @kn from its sibling rbtree which starts from
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 384) * kn->parent->dir.children. Returns %true if @kn was actually
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 385) * removed, %false if @kn wasn't on the rbtree.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 386) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 387) * Locking:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 388) * mutex_lock(kernfs_mutex)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 389) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 390) static bool kernfs_unlink_sibling(struct kernfs_node *kn)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 391) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 392) if (RB_EMPTY_NODE(&kn->rb))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 393) return false;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 394)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 395) if (kernfs_type(kn) == KERNFS_DIR)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 396) kn->parent->dir.subdirs--;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 397)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 398) rb_erase(&kn->rb, &kn->parent->dir.children);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 399) RB_CLEAR_NODE(&kn->rb);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 400) return true;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 401) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 402)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 403) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 404) * kernfs_get_active - get an active reference to kernfs_node
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 405) * @kn: kernfs_node to get an active reference to
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 406) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 407) * Get an active reference of @kn. This function is noop if @kn
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 408) * is NULL.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 409) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 410) * RETURNS:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 411) * Pointer to @kn on success, NULL on failure.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 412) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 413) struct kernfs_node *kernfs_get_active(struct kernfs_node *kn)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 414) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 415) if (unlikely(!kn))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 416) return NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 417)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 418) if (!atomic_inc_unless_negative(&kn->active))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 419) return NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 420)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 421) if (kernfs_lockdep(kn))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 422) rwsem_acquire_read(&kn->dep_map, 0, 1, _RET_IP_);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 423) return kn;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 424) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 425)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 426) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 427) * kernfs_put_active - put an active reference to kernfs_node
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 428) * @kn: kernfs_node to put an active reference to
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 429) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 430) * Put an active reference to @kn. This function is noop if @kn
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 431) * is NULL.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 432) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 433) void kernfs_put_active(struct kernfs_node *kn)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 434) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 435) int v;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 436)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 437) if (unlikely(!kn))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 438) return;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 439)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 440) if (kernfs_lockdep(kn))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 441) rwsem_release(&kn->dep_map, _RET_IP_);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 442) v = atomic_dec_return(&kn->active);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 443) if (likely(v != KN_DEACTIVATED_BIAS))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 444) return;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 445)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 446) wake_up_all(&kernfs_root(kn)->deactivate_waitq);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 447) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 448)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 449) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 450) * kernfs_drain - drain kernfs_node
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 451) * @kn: kernfs_node to drain
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 452) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 453) * Drain existing usages and nuke all existing mmaps of @kn. Mutiple
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 454) * removers may invoke this function concurrently on @kn and all will
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 455) * return after draining is complete.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 456) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 457) static void kernfs_drain(struct kernfs_node *kn)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 458) __releases(&kernfs_mutex) __acquires(&kernfs_mutex)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 459) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 460) struct kernfs_root *root = kernfs_root(kn);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 461)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 462) lockdep_assert_held(&kernfs_mutex);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 463) WARN_ON_ONCE(kernfs_active(kn));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 464)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 465) mutex_unlock(&kernfs_mutex);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 466)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 467) if (kernfs_lockdep(kn)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 468) rwsem_acquire(&kn->dep_map, 0, 0, _RET_IP_);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 469) if (atomic_read(&kn->active) != KN_DEACTIVATED_BIAS)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 470) lock_contended(&kn->dep_map, _RET_IP_);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 471) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 472)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 473) /* but everyone should wait for draining */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 474) wait_event(root->deactivate_waitq,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 475) atomic_read(&kn->active) == KN_DEACTIVATED_BIAS);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 476)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 477) if (kernfs_lockdep(kn)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 478) lock_acquired(&kn->dep_map, _RET_IP_);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 479) rwsem_release(&kn->dep_map, _RET_IP_);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 480) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 481)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 482) kernfs_drain_open_files(kn);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 483)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 484) mutex_lock(&kernfs_mutex);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 485) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 486)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 487) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 488) * kernfs_get - get a reference count on a kernfs_node
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 489) * @kn: the target kernfs_node
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 490) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 491) void kernfs_get(struct kernfs_node *kn)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 492) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 493) if (kn) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 494) WARN_ON(!atomic_read(&kn->count));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 495) atomic_inc(&kn->count);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 496) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 497) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 498) EXPORT_SYMBOL_GPL(kernfs_get);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 499)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 500) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 501) * kernfs_put - put a reference count on a kernfs_node
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 502) * @kn: the target kernfs_node
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 503) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 504) * Put a reference count of @kn and destroy it if it reached zero.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 505) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 506) void kernfs_put(struct kernfs_node *kn)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 507) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 508) struct kernfs_node *parent;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 509) struct kernfs_root *root;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 510)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 511) if (!kn || !atomic_dec_and_test(&kn->count))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 512) return;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 513) root = kernfs_root(kn);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 514) repeat:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 515) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 516) * Moving/renaming is always done while holding reference.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 517) * kn->parent won't change beneath us.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 518) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 519) parent = kn->parent;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 520)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 521) WARN_ONCE(atomic_read(&kn->active) != KN_DEACTIVATED_BIAS,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 522) "kernfs_put: %s/%s: released with incorrect active_ref %d\n",
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 523) parent ? parent->name : "", kn->name, atomic_read(&kn->active));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 524)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 525) if (kernfs_type(kn) == KERNFS_LINK)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 526) kernfs_put(kn->symlink.target_kn);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 527)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 528) kfree_const(kn->name);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 529)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 530) if (kn->iattr) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 531) simple_xattrs_free(&kn->iattr->xattrs);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 532) kmem_cache_free(kernfs_iattrs_cache, kn->iattr);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 533) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 534) spin_lock(&kernfs_idr_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 535) idr_remove(&root->ino_idr, (u32)kernfs_ino(kn));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 536) spin_unlock(&kernfs_idr_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 537) kmem_cache_free(kernfs_node_cache, kn);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 538)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 539) kn = parent;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 540) if (kn) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 541) if (atomic_dec_and_test(&kn->count))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 542) goto repeat;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 543) } else {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 544) /* just released the root kn, free @root too */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 545) idr_destroy(&root->ino_idr);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 546) kfree(root);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 547) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 548) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 549) EXPORT_SYMBOL_GPL(kernfs_put);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 550)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 551) static int kernfs_dop_revalidate(struct dentry *dentry, unsigned int flags)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 552) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 553) struct kernfs_node *kn;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 554)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 555) if (flags & LOOKUP_RCU)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 556) return -ECHILD;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 557)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 558) /* Always perform fresh lookup for negatives */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 559) if (d_really_is_negative(dentry))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 560) goto out_bad_unlocked;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 561)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 562) kn = kernfs_dentry_node(dentry);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 563) mutex_lock(&kernfs_mutex);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 564)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 565) /* The kernfs node has been deactivated */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 566) if (!kernfs_active(kn))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 567) goto out_bad;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 568)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 569) /* The kernfs node has been moved? */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 570) if (kernfs_dentry_node(dentry->d_parent) != kn->parent)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 571) goto out_bad;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 572)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 573) /* The kernfs node has been renamed */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 574) if (strcmp(dentry->d_name.name, kn->name) != 0)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 575) goto out_bad;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 576)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 577) /* The kernfs node has been moved to a different namespace */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 578) if (kn->parent && kernfs_ns_enabled(kn->parent) &&
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 579) kernfs_info(dentry->d_sb)->ns != kn->ns)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 580) goto out_bad;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 581)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 582) mutex_unlock(&kernfs_mutex);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 583) return 1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 584) out_bad:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 585) mutex_unlock(&kernfs_mutex);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 586) out_bad_unlocked:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 587) return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 588) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 589)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 590) const struct dentry_operations kernfs_dops = {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 591) .d_revalidate = kernfs_dop_revalidate,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 592) };
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 593)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 594) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 595) * kernfs_node_from_dentry - determine kernfs_node associated with a dentry
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 596) * @dentry: the dentry in question
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 597) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 598) * Return the kernfs_node associated with @dentry. If @dentry is not a
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 599) * kernfs one, %NULL is returned.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 600) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 601) * While the returned kernfs_node will stay accessible as long as @dentry
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 602) * is accessible, the returned node can be in any state and the caller is
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 603) * fully responsible for determining what's accessible.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 604) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 605) struct kernfs_node *kernfs_node_from_dentry(struct dentry *dentry)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 606) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 607) if (dentry->d_sb->s_op == &kernfs_sops &&
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 608) !d_really_is_negative(dentry))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 609) return kernfs_dentry_node(dentry);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 610) return NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 611) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 612)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 613) static struct kernfs_node *__kernfs_new_node(struct kernfs_root *root,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 614) struct kernfs_node *parent,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 615) const char *name, umode_t mode,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 616) kuid_t uid, kgid_t gid,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 617) unsigned flags)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 618) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 619) struct kernfs_node *kn;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 620) u32 id_highbits;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 621) int ret;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 622)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 623) name = kstrdup_const(name, GFP_KERNEL);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 624) if (!name)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 625) return NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 626)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 627) kn = kmem_cache_zalloc(kernfs_node_cache, GFP_KERNEL);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 628) if (!kn)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 629) goto err_out1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 630)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 631) idr_preload(GFP_KERNEL);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 632) spin_lock(&kernfs_idr_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 633) ret = idr_alloc_cyclic(&root->ino_idr, kn, 1, 0, GFP_ATOMIC);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 634) if (ret >= 0 && ret < root->last_id_lowbits)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 635) root->id_highbits++;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 636) id_highbits = root->id_highbits;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 637) root->last_id_lowbits = ret;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 638) spin_unlock(&kernfs_idr_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 639) idr_preload_end();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 640) if (ret < 0)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 641) goto err_out2;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 642)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 643) kn->id = (u64)id_highbits << 32 | ret;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 644)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 645) atomic_set(&kn->count, 1);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 646) atomic_set(&kn->active, KN_DEACTIVATED_BIAS);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 647) RB_CLEAR_NODE(&kn->rb);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 648)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 649) kn->name = name;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 650) kn->mode = mode;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 651) kn->flags = flags;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 652)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 653) if (!uid_eq(uid, GLOBAL_ROOT_UID) || !gid_eq(gid, GLOBAL_ROOT_GID)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 654) struct iattr iattr = {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 655) .ia_valid = ATTR_UID | ATTR_GID,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 656) .ia_uid = uid,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 657) .ia_gid = gid,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 658) };
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 659)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 660) ret = __kernfs_setattr(kn, &iattr);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 661) if (ret < 0)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 662) goto err_out3;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 663) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 664)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 665) if (parent) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 666) ret = security_kernfs_init_security(parent, kn);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 667) if (ret)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 668) goto err_out3;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 669) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 670)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 671) return kn;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 672)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 673) err_out3:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 674) idr_remove(&root->ino_idr, (u32)kernfs_ino(kn));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 675) err_out2:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 676) kmem_cache_free(kernfs_node_cache, kn);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 677) err_out1:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 678) kfree_const(name);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 679) return NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 680) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 681)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 682) struct kernfs_node *kernfs_new_node(struct kernfs_node *parent,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 683) const char *name, umode_t mode,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 684) kuid_t uid, kgid_t gid,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 685) unsigned flags)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 686) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 687) struct kernfs_node *kn;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 688)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 689) kn = __kernfs_new_node(kernfs_root(parent), parent,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 690) name, mode, uid, gid, flags);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 691) if (kn) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 692) kernfs_get(parent);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 693) kn->parent = parent;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 694) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 695) return kn;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 696) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 697)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 698) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 699) * kernfs_find_and_get_node_by_id - get kernfs_node from node id
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 700) * @root: the kernfs root
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 701) * @id: the target node id
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 702) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 703) * @id's lower 32bits encode ino and upper gen. If the gen portion is
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 704) * zero, all generations are matched.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 705) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 706) * RETURNS:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 707) * NULL on failure. Return a kernfs node with reference counter incremented
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 708) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 709) struct kernfs_node *kernfs_find_and_get_node_by_id(struct kernfs_root *root,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 710) u64 id)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 711) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 712) struct kernfs_node *kn;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 713) ino_t ino = kernfs_id_ino(id);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 714) u32 gen = kernfs_id_gen(id);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 715)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 716) spin_lock(&kernfs_idr_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 717)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 718) kn = idr_find(&root->ino_idr, (u32)ino);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 719) if (!kn)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 720) goto err_unlock;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 721)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 722) if (sizeof(ino_t) >= sizeof(u64)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 723) /* we looked up with the low 32bits, compare the whole */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 724) if (kernfs_ino(kn) != ino)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 725) goto err_unlock;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 726) } else {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 727) /* 0 matches all generations */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 728) if (unlikely(gen && kernfs_gen(kn) != gen))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 729) goto err_unlock;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 730) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 731)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 732) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 733) * ACTIVATED is protected with kernfs_mutex but it was clear when
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 734) * @kn was added to idr and we just wanna see it set. No need to
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 735) * grab kernfs_mutex.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 736) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 737) if (unlikely(!(kn->flags & KERNFS_ACTIVATED) ||
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 738) !atomic_inc_not_zero(&kn->count)))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 739) goto err_unlock;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 740)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 741) spin_unlock(&kernfs_idr_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 742) return kn;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 743) err_unlock:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 744) spin_unlock(&kernfs_idr_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 745) return NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 746) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 747)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 748) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 749) * kernfs_add_one - add kernfs_node to parent without warning
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 750) * @kn: kernfs_node to be added
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 751) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 752) * The caller must already have initialized @kn->parent. This
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 753) * function increments nlink of the parent's inode if @kn is a
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 754) * directory and link into the children list of the parent.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 755) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 756) * RETURNS:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 757) * 0 on success, -EEXIST if entry with the given name already
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 758) * exists.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 759) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 760) int kernfs_add_one(struct kernfs_node *kn)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 761) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 762) struct kernfs_node *parent = kn->parent;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 763) struct kernfs_iattrs *ps_iattr;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 764) bool has_ns;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 765) int ret;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 766)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 767) mutex_lock(&kernfs_mutex);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 768)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 769) ret = -EINVAL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 770) has_ns = kernfs_ns_enabled(parent);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 771) if (WARN(has_ns != (bool)kn->ns, KERN_WARNING "kernfs: ns %s in '%s' for '%s'\n",
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 772) has_ns ? "required" : "invalid", parent->name, kn->name))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 773) goto out_unlock;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 774)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 775) if (kernfs_type(parent) != KERNFS_DIR)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 776) goto out_unlock;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 777)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 778) ret = -ENOENT;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 779) if (parent->flags & KERNFS_EMPTY_DIR)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 780) goto out_unlock;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 781)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 782) if ((parent->flags & KERNFS_ACTIVATED) && !kernfs_active(parent))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 783) goto out_unlock;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 784)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 785) kn->hash = kernfs_name_hash(kn->name, kn->ns);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 786)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 787) ret = kernfs_link_sibling(kn);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 788) if (ret)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 789) goto out_unlock;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 790)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 791) /* Update timestamps on the parent */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 792) ps_iattr = parent->iattr;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 793) if (ps_iattr) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 794) ktime_get_real_ts64(&ps_iattr->ia_ctime);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 795) ps_iattr->ia_mtime = ps_iattr->ia_ctime;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 796) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 797)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 798) mutex_unlock(&kernfs_mutex);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 799)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 800) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 801) * Activate the new node unless CREATE_DEACTIVATED is requested.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 802) * If not activated here, the kernfs user is responsible for
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 803) * activating the node with kernfs_activate(). A node which hasn't
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 804) * been activated is not visible to userland and its removal won't
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 805) * trigger deactivation.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 806) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 807) if (!(kernfs_root(kn)->flags & KERNFS_ROOT_CREATE_DEACTIVATED))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 808) kernfs_activate(kn);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 809) return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 810)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 811) out_unlock:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 812) mutex_unlock(&kernfs_mutex);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 813) return ret;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 814) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 815)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 816) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 817) * kernfs_find_ns - find kernfs_node with the given name
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 818) * @parent: kernfs_node to search under
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 819) * @name: name to look for
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 820) * @ns: the namespace tag to use
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 821) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 822) * Look for kernfs_node with name @name under @parent. Returns pointer to
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 823) * the found kernfs_node on success, %NULL on failure.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 824) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 825) static struct kernfs_node *kernfs_find_ns(struct kernfs_node *parent,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 826) const unsigned char *name,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 827) const void *ns)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 828) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 829) struct rb_node *node = parent->dir.children.rb_node;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 830) bool has_ns = kernfs_ns_enabled(parent);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 831) unsigned int hash;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 832)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 833) lockdep_assert_held(&kernfs_mutex);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 834)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 835) if (has_ns != (bool)ns) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 836) WARN(1, KERN_WARNING "kernfs: ns %s in '%s' for '%s'\n",
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 837) has_ns ? "required" : "invalid", parent->name, name);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 838) return NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 839) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 840)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 841) hash = kernfs_name_hash(name, ns);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 842) while (node) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 843) struct kernfs_node *kn;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 844) int result;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 845)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 846) kn = rb_to_kn(node);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 847) result = kernfs_name_compare(hash, name, ns, kn);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 848) if (result < 0)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 849) node = node->rb_left;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 850) else if (result > 0)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 851) node = node->rb_right;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 852) else
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 853) return kn;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 854) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 855) return NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 856) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 857)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 858) static struct kernfs_node *kernfs_walk_ns(struct kernfs_node *parent,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 859) const unsigned char *path,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 860) const void *ns)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 861) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 862) size_t len;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 863) char *p, *name;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 864)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 865) lockdep_assert_held(&kernfs_mutex);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 866)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 867) /* grab kernfs_rename_lock to piggy back on kernfs_pr_cont_buf */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 868) spin_lock_irq(&kernfs_rename_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 869)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 870) len = strlcpy(kernfs_pr_cont_buf, path, sizeof(kernfs_pr_cont_buf));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 871)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 872) if (len >= sizeof(kernfs_pr_cont_buf)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 873) spin_unlock_irq(&kernfs_rename_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 874) return NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 875) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 876)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 877) p = kernfs_pr_cont_buf;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 878)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 879) while ((name = strsep(&p, "/")) && parent) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 880) if (*name == '\0')
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 881) continue;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 882) parent = kernfs_find_ns(parent, name, ns);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 883) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 884)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 885) spin_unlock_irq(&kernfs_rename_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 886)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 887) return parent;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 888) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 889)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 890) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 891) * kernfs_find_and_get_ns - find and get kernfs_node with the given name
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 892) * @parent: kernfs_node to search under
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 893) * @name: name to look for
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 894) * @ns: the namespace tag to use
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 895) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 896) * Look for kernfs_node with name @name under @parent and get a reference
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 897) * if found. This function may sleep and returns pointer to the found
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 898) * kernfs_node on success, %NULL on failure.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 899) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 900) struct kernfs_node *kernfs_find_and_get_ns(struct kernfs_node *parent,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 901) const char *name, const void *ns)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 902) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 903) struct kernfs_node *kn;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 904)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 905) mutex_lock(&kernfs_mutex);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 906) kn = kernfs_find_ns(parent, name, ns);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 907) kernfs_get(kn);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 908) mutex_unlock(&kernfs_mutex);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 909)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 910) return kn;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 911) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 912) EXPORT_SYMBOL_GPL(kernfs_find_and_get_ns);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 913)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 914) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 915) * kernfs_walk_and_get_ns - find and get kernfs_node with the given path
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 916) * @parent: kernfs_node to search under
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 917) * @path: path to look for
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 918) * @ns: the namespace tag to use
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 919) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 920) * Look for kernfs_node with path @path under @parent and get a reference
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 921) * if found. This function may sleep and returns pointer to the found
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 922) * kernfs_node on success, %NULL on failure.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 923) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 924) struct kernfs_node *kernfs_walk_and_get_ns(struct kernfs_node *parent,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 925) const char *path, const void *ns)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 926) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 927) struct kernfs_node *kn;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 928)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 929) mutex_lock(&kernfs_mutex);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 930) kn = kernfs_walk_ns(parent, path, ns);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 931) kernfs_get(kn);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 932) mutex_unlock(&kernfs_mutex);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 933)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 934) return kn;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 935) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 936)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 937) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 938) * kernfs_create_root - create a new kernfs hierarchy
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 939) * @scops: optional syscall operations for the hierarchy
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 940) * @flags: KERNFS_ROOT_* flags
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 941) * @priv: opaque data associated with the new directory
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 942) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 943) * Returns the root of the new hierarchy on success, ERR_PTR() value on
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 944) * failure.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 945) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 946) struct kernfs_root *kernfs_create_root(struct kernfs_syscall_ops *scops,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 947) unsigned int flags, void *priv)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 948) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 949) struct kernfs_root *root;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 950) struct kernfs_node *kn;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 951)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 952) root = kzalloc(sizeof(*root), GFP_KERNEL);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 953) if (!root)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 954) return ERR_PTR(-ENOMEM);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 955)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 956) idr_init(&root->ino_idr);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 957) INIT_LIST_HEAD(&root->supers);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 958)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 959) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 960) * On 64bit ino setups, id is ino. On 32bit, low 32bits are ino.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 961) * High bits generation. The starting value for both ino and
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 962) * genenration is 1. Initialize upper 32bit allocation
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 963) * accordingly.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 964) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 965) if (sizeof(ino_t) >= sizeof(u64))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 966) root->id_highbits = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 967) else
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 968) root->id_highbits = 1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 969)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 970) kn = __kernfs_new_node(root, NULL, "", S_IFDIR | S_IRUGO | S_IXUGO,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 971) GLOBAL_ROOT_UID, GLOBAL_ROOT_GID,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 972) KERNFS_DIR);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 973) if (!kn) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 974) idr_destroy(&root->ino_idr);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 975) kfree(root);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 976) return ERR_PTR(-ENOMEM);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 977) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 978)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 979) kn->priv = priv;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 980) kn->dir.root = root;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 981)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 982) root->syscall_ops = scops;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 983) root->flags = flags;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 984) root->kn = kn;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 985) init_waitqueue_head(&root->deactivate_waitq);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 986)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 987) if (!(root->flags & KERNFS_ROOT_CREATE_DEACTIVATED))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 988) kernfs_activate(kn);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 989)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 990) return root;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 991) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 992)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 993) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 994) * kernfs_destroy_root - destroy a kernfs hierarchy
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 995) * @root: root of the hierarchy to destroy
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 996) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 997) * Destroy the hierarchy anchored at @root by removing all existing
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 998) * directories and destroying @root.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 999) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1000) void kernfs_destroy_root(struct kernfs_root *root)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1001) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1002) kernfs_remove(root->kn); /* will also free @root */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1003) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1004)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1005) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1006) * kernfs_create_dir_ns - create a directory
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1007) * @parent: parent in which to create a new directory
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1008) * @name: name of the new directory
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1009) * @mode: mode of the new directory
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1010) * @uid: uid of the new directory
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1011) * @gid: gid of the new directory
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1012) * @priv: opaque data associated with the new directory
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1013) * @ns: optional namespace tag of the directory
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1014) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1015) * Returns the created node on success, ERR_PTR() value on failure.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1016) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1017) struct kernfs_node *kernfs_create_dir_ns(struct kernfs_node *parent,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1018) const char *name, umode_t mode,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1019) kuid_t uid, kgid_t gid,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1020) void *priv, const void *ns)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1021) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1022) struct kernfs_node *kn;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1023) int rc;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1024)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1025) /* allocate */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1026) kn = kernfs_new_node(parent, name, mode | S_IFDIR,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1027) uid, gid, KERNFS_DIR);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1028) if (!kn)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1029) return ERR_PTR(-ENOMEM);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1030)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1031) kn->dir.root = parent->dir.root;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1032) kn->ns = ns;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1033) kn->priv = priv;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1034)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1035) /* link in */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1036) rc = kernfs_add_one(kn);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1037) if (!rc)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1038) return kn;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1039)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1040) kernfs_put(kn);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1041) return ERR_PTR(rc);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1042) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1043)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1044) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1045) * kernfs_create_empty_dir - create an always empty directory
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1046) * @parent: parent in which to create a new directory
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1047) * @name: name of the new directory
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1048) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1049) * Returns the created node on success, ERR_PTR() value on failure.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1050) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1051) struct kernfs_node *kernfs_create_empty_dir(struct kernfs_node *parent,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1052) const char *name)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1053) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1054) struct kernfs_node *kn;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1055) int rc;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1056)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1057) /* allocate */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1058) kn = kernfs_new_node(parent, name, S_IRUGO|S_IXUGO|S_IFDIR,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1059) GLOBAL_ROOT_UID, GLOBAL_ROOT_GID, KERNFS_DIR);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1060) if (!kn)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1061) return ERR_PTR(-ENOMEM);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1062)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1063) kn->flags |= KERNFS_EMPTY_DIR;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1064) kn->dir.root = parent->dir.root;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1065) kn->ns = NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1066) kn->priv = NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1067)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1068) /* link in */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1069) rc = kernfs_add_one(kn);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1070) if (!rc)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1071) return kn;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1072)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1073) kernfs_put(kn);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1074) return ERR_PTR(rc);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1075) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1076)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1077) static struct dentry *kernfs_iop_lookup(struct inode *dir,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1078) struct dentry *dentry,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1079) unsigned int flags)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1080) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1081) struct dentry *ret;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1082) struct kernfs_node *parent = dir->i_private;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1083) struct kernfs_node *kn;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1084) struct inode *inode;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1085) const void *ns = NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1086)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1087) mutex_lock(&kernfs_mutex);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1088)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1089) if (kernfs_ns_enabled(parent))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1090) ns = kernfs_info(dir->i_sb)->ns;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1091)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1092) kn = kernfs_find_ns(parent, dentry->d_name.name, ns);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1093)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1094) /* no such entry */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1095) if (!kn || !kernfs_active(kn)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1096) ret = NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1097) goto out_unlock;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1098) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1099)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1100) /* attach dentry and inode */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1101) inode = kernfs_get_inode(dir->i_sb, kn);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1102) if (!inode) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1103) ret = ERR_PTR(-ENOMEM);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1104) goto out_unlock;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1105) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1106)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1107) /* instantiate and hash dentry */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1108) ret = d_splice_alias(inode, dentry);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1109) out_unlock:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1110) mutex_unlock(&kernfs_mutex);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1111) return ret;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1112) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1113)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1114) static int kernfs_iop_mkdir(struct inode *dir, struct dentry *dentry,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1115) umode_t mode)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1116) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1117) struct kernfs_node *parent = dir->i_private;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1118) struct kernfs_syscall_ops *scops = kernfs_root(parent)->syscall_ops;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1119) int ret;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1120)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1121) if (!scops || !scops->mkdir)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1122) return -EPERM;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1123)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1124) if (!kernfs_get_active(parent))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1125) return -ENODEV;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1126)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1127) ret = scops->mkdir(parent, dentry->d_name.name, mode);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1128)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1129) kernfs_put_active(parent);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1130) return ret;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1131) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1132)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1133) static int kernfs_iop_rmdir(struct inode *dir, struct dentry *dentry)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1134) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1135) struct kernfs_node *kn = kernfs_dentry_node(dentry);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1136) struct kernfs_syscall_ops *scops = kernfs_root(kn)->syscall_ops;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1137) int ret;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1138)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1139) if (!scops || !scops->rmdir)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1140) return -EPERM;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1141)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1142) if (!kernfs_get_active(kn))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1143) return -ENODEV;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1144)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1145) ret = scops->rmdir(kn);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1146)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1147) kernfs_put_active(kn);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1148) return ret;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1149) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1150)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1151) static int kernfs_iop_rename(struct inode *old_dir, struct dentry *old_dentry,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1152) struct inode *new_dir, struct dentry *new_dentry,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1153) unsigned int flags)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1154) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1155) struct kernfs_node *kn = kernfs_dentry_node(old_dentry);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1156) struct kernfs_node *new_parent = new_dir->i_private;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1157) struct kernfs_syscall_ops *scops = kernfs_root(kn)->syscall_ops;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1158) int ret;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1159)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1160) if (flags)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1161) return -EINVAL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1162)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1163) if (!scops || !scops->rename)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1164) return -EPERM;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1165)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1166) if (!kernfs_get_active(kn))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1167) return -ENODEV;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1168)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1169) if (!kernfs_get_active(new_parent)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1170) kernfs_put_active(kn);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1171) return -ENODEV;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1172) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1173)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1174) ret = scops->rename(kn, new_parent, new_dentry->d_name.name);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1175)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1176) kernfs_put_active(new_parent);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1177) kernfs_put_active(kn);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1178) return ret;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1179) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1180)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1181) const struct inode_operations kernfs_dir_iops = {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1182) .lookup = kernfs_iop_lookup,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1183) .permission = kernfs_iop_permission,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1184) .setattr = kernfs_iop_setattr,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1185) .getattr = kernfs_iop_getattr,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1186) .listxattr = kernfs_iop_listxattr,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1187)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1188) .mkdir = kernfs_iop_mkdir,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1189) .rmdir = kernfs_iop_rmdir,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1190) .rename = kernfs_iop_rename,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1191) };
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1192)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1193) static struct kernfs_node *kernfs_leftmost_descendant(struct kernfs_node *pos)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1194) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1195) struct kernfs_node *last;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1196)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1197) while (true) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1198) struct rb_node *rbn;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1199)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1200) last = pos;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1201)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1202) if (kernfs_type(pos) != KERNFS_DIR)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1203) break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1204)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1205) rbn = rb_first(&pos->dir.children);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1206) if (!rbn)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1207) break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1208)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1209) pos = rb_to_kn(rbn);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1210) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1211)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1212) return last;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1213) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1214)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1215) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1216) * kernfs_next_descendant_post - find the next descendant for post-order walk
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1217) * @pos: the current position (%NULL to initiate traversal)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1218) * @root: kernfs_node whose descendants to walk
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1219) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1220) * Find the next descendant to visit for post-order traversal of @root's
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1221) * descendants. @root is included in the iteration and the last node to be
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1222) * visited.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1223) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1224) static struct kernfs_node *kernfs_next_descendant_post(struct kernfs_node *pos,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1225) struct kernfs_node *root)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1226) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1227) struct rb_node *rbn;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1228)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1229) lockdep_assert_held(&kernfs_mutex);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1230)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1231) /* if first iteration, visit leftmost descendant which may be root */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1232) if (!pos)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1233) return kernfs_leftmost_descendant(root);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1234)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1235) /* if we visited @root, we're done */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1236) if (pos == root)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1237) return NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1238)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1239) /* if there's an unvisited sibling, visit its leftmost descendant */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1240) rbn = rb_next(&pos->rb);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1241) if (rbn)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1242) return kernfs_leftmost_descendant(rb_to_kn(rbn));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1243)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1244) /* no sibling left, visit parent */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1245) return pos->parent;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1246) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1247)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1248) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1249) * kernfs_activate - activate a node which started deactivated
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1250) * @kn: kernfs_node whose subtree is to be activated
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1251) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1252) * If the root has KERNFS_ROOT_CREATE_DEACTIVATED set, a newly created node
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1253) * needs to be explicitly activated. A node which hasn't been activated
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1254) * isn't visible to userland and deactivation is skipped during its
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1255) * removal. This is useful to construct atomic init sequences where
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1256) * creation of multiple nodes should either succeed or fail atomically.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1257) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1258) * The caller is responsible for ensuring that this function is not called
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1259) * after kernfs_remove*() is invoked on @kn.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1260) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1261) void kernfs_activate(struct kernfs_node *kn)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1262) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1263) struct kernfs_node *pos;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1264)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1265) mutex_lock(&kernfs_mutex);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1266)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1267) pos = NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1268) while ((pos = kernfs_next_descendant_post(pos, kn))) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1269) if (pos->flags & KERNFS_ACTIVATED)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1270) continue;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1271)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1272) WARN_ON_ONCE(pos->parent && RB_EMPTY_NODE(&pos->rb));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1273) WARN_ON_ONCE(atomic_read(&pos->active) != KN_DEACTIVATED_BIAS);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1274)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1275) atomic_sub(KN_DEACTIVATED_BIAS, &pos->active);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1276) pos->flags |= KERNFS_ACTIVATED;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1277) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1278)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1279) mutex_unlock(&kernfs_mutex);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1280) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1281)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1282) static void __kernfs_remove(struct kernfs_node *kn)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1283) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1284) struct kernfs_node *pos;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1285)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1286) lockdep_assert_held(&kernfs_mutex);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1287)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1288) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1289) * Short-circuit if non-root @kn has already finished removal.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1290) * This is for kernfs_remove_self() which plays with active ref
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1291) * after removal.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1292) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1293) if (!kn || (kn->parent && RB_EMPTY_NODE(&kn->rb)))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1294) return;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1295)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1296) pr_debug("kernfs %s: removing\n", kn->name);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1297)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1298) /* prevent any new usage under @kn by deactivating all nodes */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1299) pos = NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1300) while ((pos = kernfs_next_descendant_post(pos, kn)))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1301) if (kernfs_active(pos))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1302) atomic_add(KN_DEACTIVATED_BIAS, &pos->active);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1303)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1304) /* deactivate and unlink the subtree node-by-node */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1305) do {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1306) pos = kernfs_leftmost_descendant(kn);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1307)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1308) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1309) * kernfs_drain() drops kernfs_mutex temporarily and @pos's
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1310) * base ref could have been put by someone else by the time
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1311) * the function returns. Make sure it doesn't go away
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1312) * underneath us.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1313) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1314) kernfs_get(pos);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1315)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1316) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1317) * Drain iff @kn was activated. This avoids draining and
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1318) * its lockdep annotations for nodes which have never been
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1319) * activated and allows embedding kernfs_remove() in create
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1320) * error paths without worrying about draining.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1321) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1322) if (kn->flags & KERNFS_ACTIVATED)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1323) kernfs_drain(pos);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1324) else
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1325) WARN_ON_ONCE(atomic_read(&kn->active) != KN_DEACTIVATED_BIAS);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1326)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1327) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1328) * kernfs_unlink_sibling() succeeds once per node. Use it
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1329) * to decide who's responsible for cleanups.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1330) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1331) if (!pos->parent || kernfs_unlink_sibling(pos)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1332) struct kernfs_iattrs *ps_iattr =
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1333) pos->parent ? pos->parent->iattr : NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1334)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1335) /* update timestamps on the parent */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1336) if (ps_iattr) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1337) ktime_get_real_ts64(&ps_iattr->ia_ctime);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1338) ps_iattr->ia_mtime = ps_iattr->ia_ctime;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1339) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1340)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1341) kernfs_put(pos);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1342) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1343)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1344) kernfs_put(pos);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1345) } while (pos != kn);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1346) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1347)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1348) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1349) * kernfs_remove - remove a kernfs_node recursively
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1350) * @kn: the kernfs_node to remove
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1351) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1352) * Remove @kn along with all its subdirectories and files.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1353) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1354) void kernfs_remove(struct kernfs_node *kn)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1355) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1356) mutex_lock(&kernfs_mutex);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1357) __kernfs_remove(kn);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1358) mutex_unlock(&kernfs_mutex);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1359) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1360)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1361) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1362) * kernfs_break_active_protection - break out of active protection
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1363) * @kn: the self kernfs_node
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1364) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1365) * The caller must be running off of a kernfs operation which is invoked
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1366) * with an active reference - e.g. one of kernfs_ops. Each invocation of
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1367) * this function must also be matched with an invocation of
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1368) * kernfs_unbreak_active_protection().
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1369) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1370) * This function releases the active reference of @kn the caller is
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1371) * holding. Once this function is called, @kn may be removed at any point
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1372) * and the caller is solely responsible for ensuring that the objects it
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1373) * dereferences are accessible.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1374) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1375) void kernfs_break_active_protection(struct kernfs_node *kn)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1376) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1377) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1378) * Take out ourself out of the active ref dependency chain. If
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1379) * we're called without an active ref, lockdep will complain.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1380) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1381) kernfs_put_active(kn);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1382) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1383)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1384) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1385) * kernfs_unbreak_active_protection - undo kernfs_break_active_protection()
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1386) * @kn: the self kernfs_node
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1387) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1388) * If kernfs_break_active_protection() was called, this function must be
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1389) * invoked before finishing the kernfs operation. Note that while this
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1390) * function restores the active reference, it doesn't and can't actually
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1391) * restore the active protection - @kn may already or be in the process of
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1392) * being removed. Once kernfs_break_active_protection() is invoked, that
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1393) * protection is irreversibly gone for the kernfs operation instance.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1394) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1395) * While this function may be called at any point after
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1396) * kernfs_break_active_protection() is invoked, its most useful location
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1397) * would be right before the enclosing kernfs operation returns.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1398) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1399) void kernfs_unbreak_active_protection(struct kernfs_node *kn)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1400) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1401) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1402) * @kn->active could be in any state; however, the increment we do
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1403) * here will be undone as soon as the enclosing kernfs operation
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1404) * finishes and this temporary bump can't break anything. If @kn
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1405) * is alive, nothing changes. If @kn is being deactivated, the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1406) * soon-to-follow put will either finish deactivation or restore
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1407) * deactivated state. If @kn is already removed, the temporary
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1408) * bump is guaranteed to be gone before @kn is released.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1409) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1410) atomic_inc(&kn->active);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1411) if (kernfs_lockdep(kn))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1412) rwsem_acquire(&kn->dep_map, 0, 1, _RET_IP_);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1413) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1414)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1415) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1416) * kernfs_remove_self - remove a kernfs_node from its own method
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1417) * @kn: the self kernfs_node to remove
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1418) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1419) * The caller must be running off of a kernfs operation which is invoked
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1420) * with an active reference - e.g. one of kernfs_ops. This can be used to
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1421) * implement a file operation which deletes itself.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1422) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1423) * For example, the "delete" file for a sysfs device directory can be
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1424) * implemented by invoking kernfs_remove_self() on the "delete" file
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1425) * itself. This function breaks the circular dependency of trying to
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1426) * deactivate self while holding an active ref itself. It isn't necessary
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1427) * to modify the usual removal path to use kernfs_remove_self(). The
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1428) * "delete" implementation can simply invoke kernfs_remove_self() on self
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1429) * before proceeding with the usual removal path. kernfs will ignore later
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1430) * kernfs_remove() on self.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1431) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1432) * kernfs_remove_self() can be called multiple times concurrently on the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1433) * same kernfs_node. Only the first one actually performs removal and
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1434) * returns %true. All others will wait until the kernfs operation which
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1435) * won self-removal finishes and return %false. Note that the losers wait
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1436) * for the completion of not only the winning kernfs_remove_self() but also
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1437) * the whole kernfs_ops which won the arbitration. This can be used to
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1438) * guarantee, for example, all concurrent writes to a "delete" file to
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1439) * finish only after the whole operation is complete.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1440) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1441) bool kernfs_remove_self(struct kernfs_node *kn)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1442) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1443) bool ret;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1444)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1445) mutex_lock(&kernfs_mutex);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1446) kernfs_break_active_protection(kn);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1447)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1448) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1449) * SUICIDAL is used to arbitrate among competing invocations. Only
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1450) * the first one will actually perform removal. When the removal
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1451) * is complete, SUICIDED is set and the active ref is restored
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1452) * while holding kernfs_mutex. The ones which lost arbitration
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1453) * waits for SUICDED && drained which can happen only after the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1454) * enclosing kernfs operation which executed the winning instance
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1455) * of kernfs_remove_self() finished.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1456) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1457) if (!(kn->flags & KERNFS_SUICIDAL)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1458) kn->flags |= KERNFS_SUICIDAL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1459) __kernfs_remove(kn);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1460) kn->flags |= KERNFS_SUICIDED;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1461) ret = true;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1462) } else {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1463) wait_queue_head_t *waitq = &kernfs_root(kn)->deactivate_waitq;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1464) DEFINE_WAIT(wait);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1465)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1466) while (true) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1467) prepare_to_wait(waitq, &wait, TASK_UNINTERRUPTIBLE);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1468)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1469) if ((kn->flags & KERNFS_SUICIDED) &&
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1470) atomic_read(&kn->active) == KN_DEACTIVATED_BIAS)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1471) break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1472)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1473) mutex_unlock(&kernfs_mutex);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1474) schedule();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1475) mutex_lock(&kernfs_mutex);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1476) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1477) finish_wait(waitq, &wait);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1478) WARN_ON_ONCE(!RB_EMPTY_NODE(&kn->rb));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1479) ret = false;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1480) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1481)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1482) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1483) * This must be done while holding kernfs_mutex; otherwise, waiting
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1484) * for SUICIDED && deactivated could finish prematurely.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1485) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1486) kernfs_unbreak_active_protection(kn);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1487)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1488) mutex_unlock(&kernfs_mutex);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1489) return ret;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1490) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1491)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1492) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1493) * kernfs_remove_by_name_ns - find a kernfs_node by name and remove it
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1494) * @parent: parent of the target
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1495) * @name: name of the kernfs_node to remove
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1496) * @ns: namespace tag of the kernfs_node to remove
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1497) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1498) * Look for the kernfs_node with @name and @ns under @parent and remove it.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1499) * Returns 0 on success, -ENOENT if such entry doesn't exist.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1500) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1501) int kernfs_remove_by_name_ns(struct kernfs_node *parent, const char *name,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1502) const void *ns)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1503) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1504) struct kernfs_node *kn;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1505)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1506) if (!parent) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1507) WARN(1, KERN_WARNING "kernfs: can not remove '%s', no directory\n",
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1508) name);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1509) return -ENOENT;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1510) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1511)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1512) mutex_lock(&kernfs_mutex);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1513)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1514) kn = kernfs_find_ns(parent, name, ns);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1515) if (kn)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1516) __kernfs_remove(kn);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1517)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1518) mutex_unlock(&kernfs_mutex);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1519)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1520) if (kn)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1521) return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1522) else
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1523) return -ENOENT;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1524) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1525)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1526) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1527) * kernfs_rename_ns - move and rename a kernfs_node
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1528) * @kn: target node
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1529) * @new_parent: new parent to put @sd under
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1530) * @new_name: new name
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1531) * @new_ns: new namespace tag
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1532) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1533) int kernfs_rename_ns(struct kernfs_node *kn, struct kernfs_node *new_parent,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1534) const char *new_name, const void *new_ns)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1535) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1536) struct kernfs_node *old_parent;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1537) const char *old_name = NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1538) int error;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1539)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1540) /* can't move or rename root */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1541) if (!kn->parent)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1542) return -EINVAL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1543)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1544) mutex_lock(&kernfs_mutex);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1545)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1546) error = -ENOENT;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1547) if (!kernfs_active(kn) || !kernfs_active(new_parent) ||
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1548) (new_parent->flags & KERNFS_EMPTY_DIR))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1549) goto out;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1550)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1551) error = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1552) if ((kn->parent == new_parent) && (kn->ns == new_ns) &&
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1553) (strcmp(kn->name, new_name) == 0))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1554) goto out; /* nothing to rename */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1555)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1556) error = -EEXIST;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1557) if (kernfs_find_ns(new_parent, new_name, new_ns))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1558) goto out;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1559)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1560) /* rename kernfs_node */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1561) if (strcmp(kn->name, new_name) != 0) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1562) error = -ENOMEM;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1563) new_name = kstrdup_const(new_name, GFP_KERNEL);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1564) if (!new_name)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1565) goto out;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1566) } else {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1567) new_name = NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1568) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1569)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1570) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1571) * Move to the appropriate place in the appropriate directories rbtree.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1572) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1573) kernfs_unlink_sibling(kn);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1574) kernfs_get(new_parent);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1575)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1576) /* rename_lock protects ->parent and ->name accessors */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1577) spin_lock_irq(&kernfs_rename_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1578)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1579) old_parent = kn->parent;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1580) kn->parent = new_parent;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1581)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1582) kn->ns = new_ns;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1583) if (new_name) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1584) old_name = kn->name;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1585) kn->name = new_name;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1586) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1587)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1588) spin_unlock_irq(&kernfs_rename_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1589)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1590) kn->hash = kernfs_name_hash(kn->name, kn->ns);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1591) kernfs_link_sibling(kn);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1592)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1593) kernfs_put(old_parent);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1594) kfree_const(old_name);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1595)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1596) error = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1597) out:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1598) mutex_unlock(&kernfs_mutex);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1599) return error;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1600) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1601)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1602) /* Relationship between s_mode and the DT_xxx types */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1603) static inline unsigned char dt_type(struct kernfs_node *kn)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1604) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1605) return (kn->mode >> 12) & 15;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1606) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1607)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1608) static int kernfs_dir_fop_release(struct inode *inode, struct file *filp)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1609) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1610) kernfs_put(filp->private_data);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1611) return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1612) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1613)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1614) static struct kernfs_node *kernfs_dir_pos(const void *ns,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1615) struct kernfs_node *parent, loff_t hash, struct kernfs_node *pos)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1616) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1617) if (pos) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1618) int valid = kernfs_active(pos) &&
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1619) pos->parent == parent && hash == pos->hash;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1620) kernfs_put(pos);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1621) if (!valid)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1622) pos = NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1623) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1624) if (!pos && (hash > 1) && (hash < INT_MAX)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1625) struct rb_node *node = parent->dir.children.rb_node;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1626) while (node) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1627) pos = rb_to_kn(node);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1628)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1629) if (hash < pos->hash)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1630) node = node->rb_left;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1631) else if (hash > pos->hash)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1632) node = node->rb_right;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1633) else
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1634) break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1635) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1636) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1637) /* Skip over entries which are dying/dead or in the wrong namespace */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1638) while (pos && (!kernfs_active(pos) || pos->ns != ns)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1639) struct rb_node *node = rb_next(&pos->rb);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1640) if (!node)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1641) pos = NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1642) else
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1643) pos = rb_to_kn(node);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1644) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1645) return pos;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1646) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1647)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1648) static struct kernfs_node *kernfs_dir_next_pos(const void *ns,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1649) struct kernfs_node *parent, ino_t ino, struct kernfs_node *pos)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1650) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1651) pos = kernfs_dir_pos(ns, parent, ino, pos);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1652) if (pos) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1653) do {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1654) struct rb_node *node = rb_next(&pos->rb);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1655) if (!node)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1656) pos = NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1657) else
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1658) pos = rb_to_kn(node);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1659) } while (pos && (!kernfs_active(pos) || pos->ns != ns));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1660) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1661) return pos;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1662) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1663)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1664) static int kernfs_fop_readdir(struct file *file, struct dir_context *ctx)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1665) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1666) struct dentry *dentry = file->f_path.dentry;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1667) struct kernfs_node *parent = kernfs_dentry_node(dentry);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1668) struct kernfs_node *pos = file->private_data;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1669) const void *ns = NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1670)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1671) if (!dir_emit_dots(file, ctx))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1672) return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1673) mutex_lock(&kernfs_mutex);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1674)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1675) if (kernfs_ns_enabled(parent))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1676) ns = kernfs_info(dentry->d_sb)->ns;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1677)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1678) for (pos = kernfs_dir_pos(ns, parent, ctx->pos, pos);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1679) pos;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1680) pos = kernfs_dir_next_pos(ns, parent, ctx->pos, pos)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1681) const char *name = pos->name;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1682) unsigned int type = dt_type(pos);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1683) int len = strlen(name);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1684) ino_t ino = kernfs_ino(pos);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1685)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1686) ctx->pos = pos->hash;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1687) file->private_data = pos;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1688) kernfs_get(pos);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1689)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1690) mutex_unlock(&kernfs_mutex);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1691) if (!dir_emit(ctx, name, len, ino, type))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1692) return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1693) mutex_lock(&kernfs_mutex);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1694) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1695) mutex_unlock(&kernfs_mutex);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1696) file->private_data = NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1697) ctx->pos = INT_MAX;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1698) return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1699) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1700)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1701) const struct file_operations kernfs_dir_fops = {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1702) .read = generic_read_dir,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1703) .iterate_shared = kernfs_fop_readdir,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1704) .release = kernfs_dir_fop_release,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1705) .llseek = generic_file_llseek,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1706) };
Orange Pi5 kernel
Deprecated Linux kernel 5.10.110 for OrangePi 5/5B/5+ boards
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