^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/dcache.c
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 4) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 5) * Complete reimplementation
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 6) * (C) 1997 Thomas Schoebel-Theuer,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 7) * with heavy changes by Linus Torvalds
^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) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 11) * Notes on the allocation strategy:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 12) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 13) * The dcache is a master of the icache - whenever a dcache entry
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 14) * exists, the inode will always exist. "iput()" is done either when
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 15) * the dcache entry is deleted or garbage collected.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 16) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 17)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 18) #include <linux/ratelimit.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 19) #include <linux/string.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 20) #include <linux/mm.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 21) #include <linux/fs.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 22) #include <linux/fscrypt.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 23) #include <linux/fsnotify.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 24) #include <linux/slab.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 25) #include <linux/init.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 26) #include <linux/hash.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 27) #include <linux/cache.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 28) #include <linux/export.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 29) #include <linux/security.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 30) #include <linux/seqlock.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 31) #include <linux/memblock.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 32) #include <linux/bit_spinlock.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 33) #include <linux/rculist_bl.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 34) #include <linux/list_lru.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 35) #include "internal.h"
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 36) #include "mount.h"
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 37)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 38) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 39) * Usage:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 40) * dcache->d_inode->i_lock protects:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 41) * - i_dentry, d_u.d_alias, d_inode of aliases
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 42) * dcache_hash_bucket lock protects:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 43) * - the dcache hash table
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 44) * s_roots bl list spinlock protects:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 45) * - the s_roots list (see __d_drop)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 46) * dentry->d_sb->s_dentry_lru_lock protects:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 47) * - the dcache lru lists and counters
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 48) * d_lock protects:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 49) * - d_flags
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 50) * - d_name
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 51) * - d_lru
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 52) * - d_count
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 53) * - d_unhashed()
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 54) * - d_parent and d_subdirs
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 55) * - childrens' d_child and d_parent
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 56) * - d_u.d_alias, d_inode
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 57) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 58) * Ordering:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 59) * dentry->d_inode->i_lock
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 60) * dentry->d_lock
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 61) * dentry->d_sb->s_dentry_lru_lock
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 62) * dcache_hash_bucket lock
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 63) * s_roots lock
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 64) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 65) * If there is an ancestor relationship:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 66) * dentry->d_parent->...->d_parent->d_lock
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 67) * ...
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 68) * dentry->d_parent->d_lock
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 69) * dentry->d_lock
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 70) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 71) * If no ancestor relationship:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 72) * arbitrary, since it's serialized on rename_lock
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 73) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 74) int sysctl_vfs_cache_pressure __read_mostly = 100;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 75) EXPORT_SYMBOL_GPL(sysctl_vfs_cache_pressure);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 76)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 77) __cacheline_aligned_in_smp DEFINE_SEQLOCK(rename_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 78)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 79) EXPORT_SYMBOL(rename_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 80)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 81) static struct kmem_cache *dentry_cache __read_mostly;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 82)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 83) const struct qstr empty_name = QSTR_INIT("", 0);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 84) EXPORT_SYMBOL(empty_name);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 85) const struct qstr slash_name = QSTR_INIT("/", 1);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 86) EXPORT_SYMBOL(slash_name);
^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) * This is the single most critical data structure when it comes
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 90) * to the dcache: the hashtable for lookups. Somebody should try
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 91) * to make this good - I've just made it work.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 92) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 93) * This hash-function tries to avoid losing too many bits of hash
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 94) * information, yet avoid using a prime hash-size or similar.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 95) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 96)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 97) static unsigned int d_hash_shift __read_mostly;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 98)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 99) static struct hlist_bl_head *dentry_hashtable __read_mostly;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 100)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 101) static inline struct hlist_bl_head *d_hash(unsigned int hash)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 102) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 103) return dentry_hashtable + (hash >> d_hash_shift);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 104) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 105)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 106) #define IN_LOOKUP_SHIFT 10
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 107) static struct hlist_bl_head in_lookup_hashtable[1 << IN_LOOKUP_SHIFT];
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 108)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 109) static inline struct hlist_bl_head *in_lookup_hash(const struct dentry *parent,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 110) unsigned int hash)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 111) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 112) hash += (unsigned long) parent / L1_CACHE_BYTES;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 113) return in_lookup_hashtable + hash_32(hash, IN_LOOKUP_SHIFT);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 114) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 115)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 116)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 117) /* Statistics gathering. */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 118) struct dentry_stat_t dentry_stat = {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 119) .age_limit = 45,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 120) };
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 121)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 122) static DEFINE_PER_CPU(long, nr_dentry);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 123) static DEFINE_PER_CPU(long, nr_dentry_unused);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 124) static DEFINE_PER_CPU(long, nr_dentry_negative);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 125)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 126) #if defined(CONFIG_SYSCTL) && defined(CONFIG_PROC_FS)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 127)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 128) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 129) * Here we resort to our own counters instead of using generic per-cpu counters
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 130) * for consistency with what the vfs inode code does. We are expected to harvest
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 131) * better code and performance by having our own specialized counters.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 132) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 133) * Please note that the loop is done over all possible CPUs, not over all online
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 134) * CPUs. The reason for this is that we don't want to play games with CPUs going
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 135) * on and off. If one of them goes off, we will just keep their counters.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 136) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 137) * glommer: See cffbc8a for details, and if you ever intend to change this,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 138) * please update all vfs counters to match.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 139) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 140) static long get_nr_dentry(void)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 141) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 142) int i;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 143) long sum = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 144) for_each_possible_cpu(i)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 145) sum += per_cpu(nr_dentry, i);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 146) return sum < 0 ? 0 : sum;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 147) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 148)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 149) static long get_nr_dentry_unused(void)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 150) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 151) int i;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 152) long sum = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 153) for_each_possible_cpu(i)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 154) sum += per_cpu(nr_dentry_unused, i);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 155) return sum < 0 ? 0 : sum;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 156) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 157)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 158) static long get_nr_dentry_negative(void)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 159) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 160) int i;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 161) long sum = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 162)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 163) for_each_possible_cpu(i)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 164) sum += per_cpu(nr_dentry_negative, i);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 165) return sum < 0 ? 0 : sum;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 166) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 167)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 168) int proc_nr_dentry(struct ctl_table *table, int write, void *buffer,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 169) size_t *lenp, loff_t *ppos)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 170) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 171) dentry_stat.nr_dentry = get_nr_dentry();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 172) dentry_stat.nr_unused = get_nr_dentry_unused();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 173) dentry_stat.nr_negative = get_nr_dentry_negative();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 174) return proc_doulongvec_minmax(table, write, buffer, lenp, ppos);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 175) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 176) #endif
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 177)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 178) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 179) * Compare 2 name strings, return 0 if they match, otherwise non-zero.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 180) * The strings are both count bytes long, and count is non-zero.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 181) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 182) #ifdef CONFIG_DCACHE_WORD_ACCESS
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 183)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 184) #include <asm/word-at-a-time.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 185) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 186) * NOTE! 'cs' and 'scount' come from a dentry, so it has a
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 187) * aligned allocation for this particular component. We don't
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 188) * strictly need the load_unaligned_zeropad() safety, but it
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 189) * doesn't hurt either.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 190) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 191) * In contrast, 'ct' and 'tcount' can be from a pathname, and do
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 192) * need the careful unaligned handling.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 193) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 194) static inline int dentry_string_cmp(const unsigned char *cs, const unsigned char *ct, unsigned tcount)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 195) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 196) unsigned long a,b,mask;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 197)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 198) for (;;) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 199) a = read_word_at_a_time(cs);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 200) b = load_unaligned_zeropad(ct);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 201) if (tcount < sizeof(unsigned long))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 202) break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 203) if (unlikely(a != b))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 204) return 1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 205) cs += sizeof(unsigned long);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 206) ct += sizeof(unsigned long);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 207) tcount -= sizeof(unsigned long);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 208) if (!tcount)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 209) return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 210) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 211) mask = bytemask_from_count(tcount);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 212) return unlikely(!!((a ^ b) & mask));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 213) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 214)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 215) #else
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 216)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 217) static inline int dentry_string_cmp(const unsigned char *cs, const unsigned char *ct, unsigned tcount)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 218) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 219) do {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 220) if (*cs != *ct)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 221) return 1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 222) cs++;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 223) ct++;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 224) tcount--;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 225) } while (tcount);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 226) return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 227) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 228)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 229) #endif
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 230)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 231) static inline int dentry_cmp(const struct dentry *dentry, const unsigned char *ct, unsigned tcount)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 232) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 233) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 234) * Be careful about RCU walk racing with rename:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 235) * use 'READ_ONCE' to fetch the name pointer.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 236) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 237) * NOTE! Even if a rename will mean that the length
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 238) * was not loaded atomically, we don't care. The
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 239) * RCU walk will check the sequence count eventually,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 240) * and catch it. And we won't overrun the buffer,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 241) * because we're reading the name pointer atomically,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 242) * and a dentry name is guaranteed to be properly
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 243) * terminated with a NUL byte.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 244) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 245) * End result: even if 'len' is wrong, we'll exit
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 246) * early because the data cannot match (there can
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 247) * be no NUL in the ct/tcount data)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 248) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 249) const unsigned char *cs = READ_ONCE(dentry->d_name.name);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 250)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 251) return dentry_string_cmp(cs, ct, tcount);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 252) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 253)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 254) struct external_name {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 255) union {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 256) atomic_t count;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 257) struct rcu_head head;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 258) } u;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 259) unsigned char name[];
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 260) };
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 261)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 262) static inline struct external_name *external_name(struct dentry *dentry)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 263) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 264) return container_of(dentry->d_name.name, struct external_name, name[0]);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 265) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 266)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 267) static void __d_free(struct rcu_head *head)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 268) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 269) struct dentry *dentry = container_of(head, struct dentry, d_u.d_rcu);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 270)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 271) kmem_cache_free(dentry_cache, dentry);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 272) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 273)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 274) static void __d_free_external(struct rcu_head *head)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 275) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 276) struct dentry *dentry = container_of(head, struct dentry, d_u.d_rcu);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 277) kfree(external_name(dentry));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 278) kmem_cache_free(dentry_cache, dentry);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 279) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 280)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 281) static inline int dname_external(const struct dentry *dentry)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 282) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 283) return dentry->d_name.name != dentry->d_iname;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 284) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 285)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 286) void take_dentry_name_snapshot(struct name_snapshot *name, struct dentry *dentry)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 287) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 288) spin_lock(&dentry->d_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 289) name->name = dentry->d_name;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 290) if (unlikely(dname_external(dentry))) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 291) atomic_inc(&external_name(dentry)->u.count);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 292) } else {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 293) memcpy(name->inline_name, dentry->d_iname,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 294) dentry->d_name.len + 1);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 295) name->name.name = name->inline_name;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 296) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 297) spin_unlock(&dentry->d_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 298) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 299) EXPORT_SYMBOL(take_dentry_name_snapshot);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 300)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 301) void release_dentry_name_snapshot(struct name_snapshot *name)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 302) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 303) if (unlikely(name->name.name != name->inline_name)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 304) struct external_name *p;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 305) p = container_of(name->name.name, struct external_name, name[0]);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 306) if (unlikely(atomic_dec_and_test(&p->u.count)))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 307) kfree_rcu(p, u.head);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 308) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 309) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 310) EXPORT_SYMBOL(release_dentry_name_snapshot);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 311)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 312) static inline void __d_set_inode_and_type(struct dentry *dentry,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 313) struct inode *inode,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 314) unsigned type_flags)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 315) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 316) unsigned flags;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 317)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 318) dentry->d_inode = inode;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 319) flags = READ_ONCE(dentry->d_flags);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 320) flags &= ~(DCACHE_ENTRY_TYPE | DCACHE_FALLTHRU);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 321) flags |= type_flags;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 322) smp_store_release(&dentry->d_flags, flags);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 323) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 324)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 325) static inline void __d_clear_type_and_inode(struct dentry *dentry)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 326) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 327) unsigned flags = READ_ONCE(dentry->d_flags);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 328)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 329) flags &= ~(DCACHE_ENTRY_TYPE | DCACHE_FALLTHRU);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 330) WRITE_ONCE(dentry->d_flags, flags);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 331) dentry->d_inode = NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 332) if (dentry->d_flags & DCACHE_LRU_LIST)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 333) this_cpu_inc(nr_dentry_negative);
^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) static void dentry_free(struct dentry *dentry)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 337) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 338) WARN_ON(!hlist_unhashed(&dentry->d_u.d_alias));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 339) if (unlikely(dname_external(dentry))) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 340) struct external_name *p = external_name(dentry);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 341) if (likely(atomic_dec_and_test(&p->u.count))) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 342) call_rcu(&dentry->d_u.d_rcu, __d_free_external);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 343) return;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 344) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 345) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 346) /* if dentry was never visible to RCU, immediate free is OK */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 347) if (dentry->d_flags & DCACHE_NORCU)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 348) __d_free(&dentry->d_u.d_rcu);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 349) else
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 350) call_rcu(&dentry->d_u.d_rcu, __d_free);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 351) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 352)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 353) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 354) * Release the dentry's inode, using the filesystem
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 355) * d_iput() operation if defined.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 356) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 357) static void dentry_unlink_inode(struct dentry * dentry)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 358) __releases(dentry->d_lock)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 359) __releases(dentry->d_inode->i_lock)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 360) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 361) struct inode *inode = dentry->d_inode;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 362)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 363) raw_write_seqcount_begin(&dentry->d_seq);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 364) __d_clear_type_and_inode(dentry);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 365) hlist_del_init(&dentry->d_u.d_alias);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 366) raw_write_seqcount_end(&dentry->d_seq);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 367) spin_unlock(&dentry->d_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 368) spin_unlock(&inode->i_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 369) if (!inode->i_nlink)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 370) fsnotify_inoderemove(inode);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 371) if (dentry->d_op && dentry->d_op->d_iput)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 372) dentry->d_op->d_iput(dentry, inode);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 373) else
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 374) iput(inode);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 375) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 376)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 377) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 378) * The DCACHE_LRU_LIST bit is set whenever the 'd_lru' entry
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 379) * is in use - which includes both the "real" per-superblock
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 380) * LRU list _and_ the DCACHE_SHRINK_LIST use.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 381) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 382) * The DCACHE_SHRINK_LIST bit is set whenever the dentry is
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 383) * on the shrink list (ie not on the superblock LRU list).
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 384) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 385) * The per-cpu "nr_dentry_unused" counters are updated with
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 386) * the DCACHE_LRU_LIST bit.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 387) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 388) * The per-cpu "nr_dentry_negative" counters are only updated
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 389) * when deleted from or added to the per-superblock LRU list, not
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 390) * from/to the shrink list. That is to avoid an unneeded dec/inc
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 391) * pair when moving from LRU to shrink list in select_collect().
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 392) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 393) * These helper functions make sure we always follow the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 394) * rules. d_lock must be held by the caller.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 395) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 396) #define D_FLAG_VERIFY(dentry,x) WARN_ON_ONCE(((dentry)->d_flags & (DCACHE_LRU_LIST | DCACHE_SHRINK_LIST)) != (x))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 397) static void d_lru_add(struct dentry *dentry)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 398) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 399) D_FLAG_VERIFY(dentry, 0);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 400) dentry->d_flags |= DCACHE_LRU_LIST;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 401) this_cpu_inc(nr_dentry_unused);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 402) if (d_is_negative(dentry))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 403) this_cpu_inc(nr_dentry_negative);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 404) WARN_ON_ONCE(!list_lru_add(&dentry->d_sb->s_dentry_lru, &dentry->d_lru));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 405) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 406)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 407) static void d_lru_del(struct dentry *dentry)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 408) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 409) D_FLAG_VERIFY(dentry, DCACHE_LRU_LIST);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 410) dentry->d_flags &= ~DCACHE_LRU_LIST;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 411) this_cpu_dec(nr_dentry_unused);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 412) if (d_is_negative(dentry))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 413) this_cpu_dec(nr_dentry_negative);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 414) WARN_ON_ONCE(!list_lru_del(&dentry->d_sb->s_dentry_lru, &dentry->d_lru));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 415) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 416)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 417) static void d_shrink_del(struct dentry *dentry)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 418) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 419) D_FLAG_VERIFY(dentry, DCACHE_SHRINK_LIST | DCACHE_LRU_LIST);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 420) list_del_init(&dentry->d_lru);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 421) dentry->d_flags &= ~(DCACHE_SHRINK_LIST | DCACHE_LRU_LIST);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 422) this_cpu_dec(nr_dentry_unused);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 423) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 424)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 425) static void d_shrink_add(struct dentry *dentry, struct list_head *list)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 426) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 427) D_FLAG_VERIFY(dentry, 0);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 428) list_add(&dentry->d_lru, list);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 429) dentry->d_flags |= DCACHE_SHRINK_LIST | DCACHE_LRU_LIST;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 430) this_cpu_inc(nr_dentry_unused);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 431) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 432)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 433) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 434) * These can only be called under the global LRU lock, ie during the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 435) * callback for freeing the LRU list. "isolate" removes it from the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 436) * LRU lists entirely, while shrink_move moves it to the indicated
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 437) * private list.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 438) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 439) static void d_lru_isolate(struct list_lru_one *lru, struct dentry *dentry)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 440) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 441) D_FLAG_VERIFY(dentry, DCACHE_LRU_LIST);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 442) dentry->d_flags &= ~DCACHE_LRU_LIST;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 443) this_cpu_dec(nr_dentry_unused);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 444) if (d_is_negative(dentry))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 445) this_cpu_dec(nr_dentry_negative);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 446) list_lru_isolate(lru, &dentry->d_lru);
^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) static void d_lru_shrink_move(struct list_lru_one *lru, struct dentry *dentry,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 450) struct list_head *list)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 451) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 452) D_FLAG_VERIFY(dentry, DCACHE_LRU_LIST);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 453) dentry->d_flags |= DCACHE_SHRINK_LIST;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 454) if (d_is_negative(dentry))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 455) this_cpu_dec(nr_dentry_negative);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 456) list_lru_isolate_move(lru, &dentry->d_lru, list);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 457) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 458)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 459) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 460) * d_drop - drop a dentry
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 461) * @dentry: dentry to drop
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 462) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 463) * d_drop() unhashes the entry from the parent dentry hashes, so that it won't
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 464) * be found through a VFS lookup any more. Note that this is different from
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 465) * deleting the dentry - d_delete will try to mark the dentry negative if
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 466) * possible, giving a successful _negative_ lookup, while d_drop will
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 467) * just make the cache lookup fail.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 468) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 469) * d_drop() is used mainly for stuff that wants to invalidate a dentry for some
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 470) * reason (NFS timeouts or autofs deletes).
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 471) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 472) * __d_drop requires dentry->d_lock
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 473) * ___d_drop doesn't mark dentry as "unhashed"
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 474) * (dentry->d_hash.pprev will be LIST_POISON2, not NULL).
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 475) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 476) static void ___d_drop(struct dentry *dentry)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 477) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 478) struct hlist_bl_head *b;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 479) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 480) * Hashed dentries are normally on the dentry hashtable,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 481) * with the exception of those newly allocated by
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 482) * d_obtain_root, which are always IS_ROOT:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 483) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 484) if (unlikely(IS_ROOT(dentry)))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 485) b = &dentry->d_sb->s_roots;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 486) else
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 487) b = d_hash(dentry->d_name.hash);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 488)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 489) hlist_bl_lock(b);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 490) __hlist_bl_del(&dentry->d_hash);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 491) hlist_bl_unlock(b);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 492) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 493)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 494) void __d_drop(struct dentry *dentry)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 495) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 496) if (!d_unhashed(dentry)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 497) ___d_drop(dentry);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 498) dentry->d_hash.pprev = NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 499) write_seqcount_invalidate(&dentry->d_seq);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 500) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 501) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 502) EXPORT_SYMBOL(__d_drop);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 503)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 504) void d_drop(struct dentry *dentry)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 505) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 506) spin_lock(&dentry->d_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 507) __d_drop(dentry);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 508) spin_unlock(&dentry->d_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 509) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 510) EXPORT_SYMBOL(d_drop);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 511)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 512) static inline void dentry_unlist(struct dentry *dentry, struct dentry *parent)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 513) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 514) struct dentry *next;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 515) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 516) * Inform d_walk() and shrink_dentry_list() that we are no longer
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 517) * attached to the dentry tree
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 518) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 519) dentry->d_flags |= DCACHE_DENTRY_KILLED;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 520) if (unlikely(list_empty(&dentry->d_child)))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 521) return;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 522) __list_del_entry(&dentry->d_child);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 523) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 524) * Cursors can move around the list of children. While we'd been
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 525) * a normal list member, it didn't matter - ->d_child.next would've
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 526) * been updated. However, from now on it won't be and for the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 527) * things like d_walk() it might end up with a nasty surprise.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 528) * Normally d_walk() doesn't care about cursors moving around -
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 529) * ->d_lock on parent prevents that and since a cursor has no children
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 530) * of its own, we get through it without ever unlocking the parent.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 531) * There is one exception, though - if we ascend from a child that
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 532) * gets killed as soon as we unlock it, the next sibling is found
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 533) * using the value left in its ->d_child.next. And if _that_
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 534) * pointed to a cursor, and cursor got moved (e.g. by lseek())
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 535) * before d_walk() regains parent->d_lock, we'll end up skipping
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 536) * everything the cursor had been moved past.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 537) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 538) * Solution: make sure that the pointer left behind in ->d_child.next
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 539) * points to something that won't be moving around. I.e. skip the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 540) * cursors.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 541) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 542) while (dentry->d_child.next != &parent->d_subdirs) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 543) next = list_entry(dentry->d_child.next, struct dentry, d_child);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 544) if (likely(!(next->d_flags & DCACHE_DENTRY_CURSOR)))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 545) break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 546) dentry->d_child.next = next->d_child.next;
^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)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 550) static void __dentry_kill(struct dentry *dentry)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 551) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 552) struct dentry *parent = NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 553) bool can_free = true;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 554) if (!IS_ROOT(dentry))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 555) parent = dentry->d_parent;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 556)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 557) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 558) * The dentry is now unrecoverably dead to the world.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 559) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 560) lockref_mark_dead(&dentry->d_lockref);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 561)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 562) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 563) * inform the fs via d_prune that this dentry is about to be
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 564) * unhashed and destroyed.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 565) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 566) if (dentry->d_flags & DCACHE_OP_PRUNE)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 567) dentry->d_op->d_prune(dentry);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 568)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 569) if (dentry->d_flags & DCACHE_LRU_LIST) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 570) if (!(dentry->d_flags & DCACHE_SHRINK_LIST))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 571) d_lru_del(dentry);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 572) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 573) /* if it was on the hash then remove it */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 574) __d_drop(dentry);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 575) dentry_unlist(dentry, parent);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 576) if (parent)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 577) spin_unlock(&parent->d_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 578) if (dentry->d_inode)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 579) dentry_unlink_inode(dentry);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 580) else
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 581) spin_unlock(&dentry->d_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 582) this_cpu_dec(nr_dentry);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 583) if (dentry->d_op && dentry->d_op->d_release)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 584) dentry->d_op->d_release(dentry);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 585)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 586) spin_lock(&dentry->d_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 587) if (dentry->d_flags & DCACHE_SHRINK_LIST) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 588) dentry->d_flags |= DCACHE_MAY_FREE;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 589) can_free = false;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 590) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 591) spin_unlock(&dentry->d_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 592) if (likely(can_free))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 593) dentry_free(dentry);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 594) cond_resched();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 595) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 596)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 597) static struct dentry *__lock_parent(struct dentry *dentry)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 598) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 599) struct dentry *parent;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 600) rcu_read_lock();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 601) spin_unlock(&dentry->d_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 602) again:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 603) parent = READ_ONCE(dentry->d_parent);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 604) spin_lock(&parent->d_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 605) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 606) * We can't blindly lock dentry until we are sure
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 607) * that we won't violate the locking order.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 608) * Any changes of dentry->d_parent must have
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 609) * been done with parent->d_lock held, so
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 610) * spin_lock() above is enough of a barrier
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 611) * for checking if it's still our child.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 612) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 613) if (unlikely(parent != dentry->d_parent)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 614) spin_unlock(&parent->d_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 615) goto again;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 616) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 617) rcu_read_unlock();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 618) if (parent != dentry)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 619) spin_lock_nested(&dentry->d_lock, DENTRY_D_LOCK_NESTED);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 620) else
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 621) parent = NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 622) return parent;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 623) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 624)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 625) static inline struct dentry *lock_parent(struct dentry *dentry)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 626) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 627) struct dentry *parent = dentry->d_parent;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 628) if (IS_ROOT(dentry))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 629) return NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 630) if (likely(spin_trylock(&parent->d_lock)))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 631) return parent;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 632) return __lock_parent(dentry);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 633) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 634)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 635) static inline bool retain_dentry(struct dentry *dentry)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 636) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 637) WARN_ON(d_in_lookup(dentry));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 638)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 639) /* Unreachable? Get rid of it */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 640) if (unlikely(d_unhashed(dentry)))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 641) return false;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 642)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 643) if (unlikely(dentry->d_flags & DCACHE_DISCONNECTED))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 644) return false;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 645)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 646) if (unlikely(dentry->d_flags & DCACHE_OP_DELETE)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 647) if (dentry->d_op->d_delete(dentry))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 648) return false;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 649) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 650)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 651) if (unlikely(dentry->d_flags & DCACHE_DONTCACHE))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 652) return false;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 653)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 654) /* retain; LRU fodder */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 655) dentry->d_lockref.count--;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 656) if (unlikely(!(dentry->d_flags & DCACHE_LRU_LIST)))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 657) d_lru_add(dentry);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 658) else if (unlikely(!(dentry->d_flags & DCACHE_REFERENCED)))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 659) dentry->d_flags |= DCACHE_REFERENCED;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 660) return true;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 661) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 662)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 663) void d_mark_dontcache(struct inode *inode)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 664) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 665) struct dentry *de;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 666)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 667) spin_lock(&inode->i_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 668) hlist_for_each_entry(de, &inode->i_dentry, d_u.d_alias) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 669) spin_lock(&de->d_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 670) de->d_flags |= DCACHE_DONTCACHE;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 671) spin_unlock(&de->d_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 672) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 673) inode->i_state |= I_DONTCACHE;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 674) spin_unlock(&inode->i_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 675) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 676) EXPORT_SYMBOL(d_mark_dontcache);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 677)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 678) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 679) * Finish off a dentry we've decided to kill.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 680) * dentry->d_lock must be held, returns with it unlocked.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 681) * Returns dentry requiring refcount drop, or NULL if we're done.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 682) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 683) static struct dentry *dentry_kill(struct dentry *dentry)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 684) __releases(dentry->d_lock)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 685) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 686) struct inode *inode = dentry->d_inode;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 687) struct dentry *parent = NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 688)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 689) if (inode && unlikely(!spin_trylock(&inode->i_lock)))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 690) goto slow_positive;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 691)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 692) if (!IS_ROOT(dentry)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 693) parent = dentry->d_parent;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 694) if (unlikely(!spin_trylock(&parent->d_lock))) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 695) parent = __lock_parent(dentry);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 696) if (likely(inode || !dentry->d_inode))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 697) goto got_locks;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 698) /* negative that became positive */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 699) if (parent)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 700) spin_unlock(&parent->d_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 701) inode = dentry->d_inode;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 702) goto slow_positive;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 703) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 704) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 705) __dentry_kill(dentry);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 706) return parent;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 707)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 708) slow_positive:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 709) spin_unlock(&dentry->d_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 710) spin_lock(&inode->i_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 711) spin_lock(&dentry->d_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 712) parent = lock_parent(dentry);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 713) got_locks:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 714) if (unlikely(dentry->d_lockref.count != 1)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 715) dentry->d_lockref.count--;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 716) } else if (likely(!retain_dentry(dentry))) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 717) __dentry_kill(dentry);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 718) return parent;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 719) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 720) /* we are keeping it, after all */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 721) if (inode)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 722) spin_unlock(&inode->i_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 723) if (parent)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 724) spin_unlock(&parent->d_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 725) spin_unlock(&dentry->d_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 726) return NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 727) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 728)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 729) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 730) * Try to do a lockless dput(), and return whether that was successful.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 731) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 732) * If unsuccessful, we return false, having already taken the dentry lock.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 733) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 734) * The caller needs to hold the RCU read lock, so that the dentry is
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 735) * guaranteed to stay around even if the refcount goes down to zero!
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 736) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 737) static inline bool fast_dput(struct dentry *dentry)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 738) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 739) int ret;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 740) unsigned int d_flags;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 741)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 742) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 743) * If we have a d_op->d_delete() operation, we sould not
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 744) * let the dentry count go to zero, so use "put_or_lock".
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 745) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 746) if (unlikely(dentry->d_flags & DCACHE_OP_DELETE))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 747) return lockref_put_or_lock(&dentry->d_lockref);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 748)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 749) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 750) * .. otherwise, we can try to just decrement the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 751) * lockref optimistically.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 752) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 753) ret = lockref_put_return(&dentry->d_lockref);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 754)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 755) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 756) * If the lockref_put_return() failed due to the lock being held
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 757) * by somebody else, the fast path has failed. We will need to
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 758) * get the lock, and then check the count again.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 759) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 760) if (unlikely(ret < 0)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 761) spin_lock(&dentry->d_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 762) if (dentry->d_lockref.count > 1) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 763) dentry->d_lockref.count--;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 764) spin_unlock(&dentry->d_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 765) return true;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 766) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 767) return false;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 768) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 769)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 770) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 771) * If we weren't the last ref, we're done.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 772) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 773) if (ret)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 774) return true;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 775)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 776) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 777) * Careful, careful. The reference count went down
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 778) * to zero, but we don't hold the dentry lock, so
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 779) * somebody else could get it again, and do another
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 780) * dput(), and we need to not race with that.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 781) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 782) * However, there is a very special and common case
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 783) * where we don't care, because there is nothing to
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 784) * do: the dentry is still hashed, it does not have
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 785) * a 'delete' op, and it's referenced and already on
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 786) * the LRU list.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 787) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 788) * NOTE! Since we aren't locked, these values are
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 789) * not "stable". However, it is sufficient that at
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 790) * some point after we dropped the reference the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 791) * dentry was hashed and the flags had the proper
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 792) * value. Other dentry users may have re-gotten
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 793) * a reference to the dentry and change that, but
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 794) * our work is done - we can leave the dentry
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 795) * around with a zero refcount.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 796) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 797) smp_rmb();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 798) d_flags = READ_ONCE(dentry->d_flags);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 799) d_flags &= DCACHE_REFERENCED | DCACHE_LRU_LIST | DCACHE_DISCONNECTED;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 800)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 801) /* Nothing to do? Dropping the reference was all we needed? */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 802) if (d_flags == (DCACHE_REFERENCED | DCACHE_LRU_LIST) && !d_unhashed(dentry))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 803) return true;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 804)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 805) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 806) * Not the fast normal case? Get the lock. We've already decremented
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 807) * the refcount, but we'll need to re-check the situation after
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 808) * getting the lock.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 809) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 810) spin_lock(&dentry->d_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 811)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 812) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 813) * Did somebody else grab a reference to it in the meantime, and
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 814) * we're no longer the last user after all? Alternatively, somebody
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 815) * else could have killed it and marked it dead. Either way, we
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 816) * don't need to do anything else.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 817) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 818) if (dentry->d_lockref.count) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 819) spin_unlock(&dentry->d_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 820) return true;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 821) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 822)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 823) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 824) * Re-get the reference we optimistically dropped. We hold the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 825) * lock, and we just tested that it was zero, so we can just
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 826) * set it to 1.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 827) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 828) dentry->d_lockref.count = 1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 829) return false;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 830) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 831)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 832)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 833) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 834) * This is dput
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 835) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 836) * This is complicated by the fact that we do not want to put
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 837) * dentries that are no longer on any hash chain on the unused
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 838) * list: we'd much rather just get rid of them immediately.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 839) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 840) * However, that implies that we have to traverse the dentry
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 841) * tree upwards to the parents which might _also_ now be
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 842) * scheduled for deletion (it may have been only waiting for
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 843) * its last child to go away).
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 844) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 845) * This tail recursion is done by hand as we don't want to depend
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 846) * on the compiler to always get this right (gcc generally doesn't).
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 847) * Real recursion would eat up our stack space.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 848) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 849)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 850) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 851) * dput - release a dentry
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 852) * @dentry: dentry to release
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 853) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 854) * Release a dentry. This will drop the usage count and if appropriate
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 855) * call the dentry unlink method as well as removing it from the queues and
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 856) * releasing its resources. If the parent dentries were scheduled for release
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 857) * they too may now get deleted.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 858) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 859) void dput(struct dentry *dentry)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 860) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 861) while (dentry) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 862) might_sleep();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 863)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 864) rcu_read_lock();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 865) if (likely(fast_dput(dentry))) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 866) rcu_read_unlock();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 867) return;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 868) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 869)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 870) /* Slow case: now with the dentry lock held */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 871) rcu_read_unlock();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 872)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 873) if (likely(retain_dentry(dentry))) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 874) spin_unlock(&dentry->d_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 875) return;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 876) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 877)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 878) dentry = dentry_kill(dentry);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 879) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 880) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 881) EXPORT_SYMBOL(dput);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 882)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 883) static void __dput_to_list(struct dentry *dentry, struct list_head *list)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 884) __must_hold(&dentry->d_lock)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 885) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 886) if (dentry->d_flags & DCACHE_SHRINK_LIST) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 887) /* let the owner of the list it's on deal with it */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 888) --dentry->d_lockref.count;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 889) } else {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 890) if (dentry->d_flags & DCACHE_LRU_LIST)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 891) d_lru_del(dentry);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 892) if (!--dentry->d_lockref.count)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 893) d_shrink_add(dentry, list);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 894) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 895) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 896)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 897) void dput_to_list(struct dentry *dentry, struct list_head *list)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 898) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 899) rcu_read_lock();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 900) if (likely(fast_dput(dentry))) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 901) rcu_read_unlock();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 902) return;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 903) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 904) rcu_read_unlock();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 905) if (!retain_dentry(dentry))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 906) __dput_to_list(dentry, list);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 907) spin_unlock(&dentry->d_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 908) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 909)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 910) /* This must be called with d_lock held */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 911) static inline void __dget_dlock(struct dentry *dentry)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 912) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 913) dentry->d_lockref.count++;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 914) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 915)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 916) static inline void __dget(struct dentry *dentry)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 917) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 918) lockref_get(&dentry->d_lockref);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 919) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 920)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 921) struct dentry *dget_parent(struct dentry *dentry)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 922) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 923) int gotref;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 924) struct dentry *ret;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 925) unsigned seq;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 926)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 927) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 928) * Do optimistic parent lookup without any
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 929) * locking.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 930) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 931) rcu_read_lock();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 932) seq = raw_seqcount_begin(&dentry->d_seq);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 933) ret = READ_ONCE(dentry->d_parent);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 934) gotref = lockref_get_not_zero(&ret->d_lockref);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 935) rcu_read_unlock();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 936) if (likely(gotref)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 937) if (!read_seqcount_retry(&dentry->d_seq, seq))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 938) return ret;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 939) dput(ret);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 940) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 941)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 942) repeat:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 943) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 944) * Don't need rcu_dereference because we re-check it was correct under
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 945) * the lock.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 946) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 947) rcu_read_lock();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 948) ret = dentry->d_parent;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 949) spin_lock(&ret->d_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 950) if (unlikely(ret != dentry->d_parent)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 951) spin_unlock(&ret->d_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 952) rcu_read_unlock();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 953) goto repeat;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 954) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 955) rcu_read_unlock();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 956) BUG_ON(!ret->d_lockref.count);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 957) ret->d_lockref.count++;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 958) spin_unlock(&ret->d_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 959) return ret;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 960) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 961) EXPORT_SYMBOL(dget_parent);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 962)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 963) static struct dentry * __d_find_any_alias(struct inode *inode)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 964) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 965) struct dentry *alias;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 966)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 967) if (hlist_empty(&inode->i_dentry))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 968) return NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 969) alias = hlist_entry(inode->i_dentry.first, struct dentry, d_u.d_alias);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 970) __dget(alias);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 971) return alias;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 972) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 973)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 974) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 975) * d_find_any_alias - find any alias for a given inode
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 976) * @inode: inode to find an alias for
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 977) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 978) * If any aliases exist for the given inode, take and return a
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 979) * reference for one of them. If no aliases exist, return %NULL.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 980) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 981) struct dentry *d_find_any_alias(struct inode *inode)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 982) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 983) struct dentry *de;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 984)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 985) spin_lock(&inode->i_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 986) de = __d_find_any_alias(inode);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 987) spin_unlock(&inode->i_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 988) return de;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 989) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 990) EXPORT_SYMBOL(d_find_any_alias);
^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) * d_find_alias - grab a hashed alias of inode
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 994) * @inode: inode in question
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 995) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 996) * If inode has a hashed alias, or is a directory and has any alias,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 997) * acquire the reference to alias and return it. Otherwise return NULL.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 998) * Notice that if inode is a directory there can be only one alias and
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 999) * it can be unhashed only if it has no children, or if it is the root
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1000) * of a filesystem, or if the directory was renamed and d_revalidate
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1001) * was the first vfs operation to notice.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1002) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1003) * If the inode has an IS_ROOT, DCACHE_DISCONNECTED alias, then prefer
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1004) * any other hashed alias over that one.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1005) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1006) static struct dentry *__d_find_alias(struct inode *inode)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1007) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1008) struct dentry *alias;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1009)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1010) if (S_ISDIR(inode->i_mode))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1011) return __d_find_any_alias(inode);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1012)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1013) hlist_for_each_entry(alias, &inode->i_dentry, d_u.d_alias) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1014) spin_lock(&alias->d_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1015) if (!d_unhashed(alias)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1016) __dget_dlock(alias);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1017) spin_unlock(&alias->d_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1018) return alias;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1019) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1020) spin_unlock(&alias->d_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1021) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1022) return NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1023) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1024)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1025) struct dentry *d_find_alias(struct inode *inode)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1026) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1027) struct dentry *de = NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1028)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1029) if (!hlist_empty(&inode->i_dentry)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1030) spin_lock(&inode->i_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1031) de = __d_find_alias(inode);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1032) spin_unlock(&inode->i_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1033) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1034) return de;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1035) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1036) EXPORT_SYMBOL(d_find_alias);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1037)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1038) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1039) * Try to kill dentries associated with this inode.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1040) * WARNING: you must own a reference to inode.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1041) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1042) void d_prune_aliases(struct inode *inode)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1043) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1044) struct dentry *dentry;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1045) restart:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1046) spin_lock(&inode->i_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1047) hlist_for_each_entry(dentry, &inode->i_dentry, d_u.d_alias) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1048) spin_lock(&dentry->d_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1049) if (!dentry->d_lockref.count) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1050) struct dentry *parent = lock_parent(dentry);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1051) if (likely(!dentry->d_lockref.count)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1052) __dentry_kill(dentry);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1053) dput(parent);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1054) goto restart;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1055) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1056) if (parent)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1057) spin_unlock(&parent->d_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1058) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1059) spin_unlock(&dentry->d_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1060) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1061) spin_unlock(&inode->i_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1062) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1063) EXPORT_SYMBOL(d_prune_aliases);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1064)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1065) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1066) * Lock a dentry from shrink list.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1067) * Called under rcu_read_lock() and dentry->d_lock; the former
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1068) * guarantees that nothing we access will be freed under us.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1069) * Note that dentry is *not* protected from concurrent dentry_kill(),
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1070) * d_delete(), etc.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1071) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1072) * Return false if dentry has been disrupted or grabbed, leaving
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1073) * the caller to kick it off-list. Otherwise, return true and have
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1074) * that dentry's inode and parent both locked.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1075) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1076) static bool shrink_lock_dentry(struct dentry *dentry)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1077) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1078) struct inode *inode;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1079) struct dentry *parent;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1080)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1081) if (dentry->d_lockref.count)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1082) return false;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1083)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1084) inode = dentry->d_inode;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1085) if (inode && unlikely(!spin_trylock(&inode->i_lock))) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1086) spin_unlock(&dentry->d_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1087) spin_lock(&inode->i_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1088) spin_lock(&dentry->d_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1089) if (unlikely(dentry->d_lockref.count))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1090) goto out;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1091) /* changed inode means that somebody had grabbed it */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1092) if (unlikely(inode != dentry->d_inode))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1093) goto out;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1094) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1095)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1096) parent = dentry->d_parent;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1097) if (IS_ROOT(dentry) || likely(spin_trylock(&parent->d_lock)))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1098) return true;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1099)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1100) spin_unlock(&dentry->d_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1101) spin_lock(&parent->d_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1102) if (unlikely(parent != dentry->d_parent)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1103) spin_unlock(&parent->d_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1104) spin_lock(&dentry->d_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1105) goto out;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1106) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1107) spin_lock_nested(&dentry->d_lock, DENTRY_D_LOCK_NESTED);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1108) if (likely(!dentry->d_lockref.count))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1109) return true;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1110) spin_unlock(&parent->d_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1111) out:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1112) if (inode)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1113) spin_unlock(&inode->i_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1114) return false;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1115) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1116)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1117) void shrink_dentry_list(struct list_head *list)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1118) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1119) while (!list_empty(list)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1120) struct dentry *dentry, *parent;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1121)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1122) dentry = list_entry(list->prev, struct dentry, d_lru);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1123) spin_lock(&dentry->d_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1124) rcu_read_lock();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1125) if (!shrink_lock_dentry(dentry)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1126) bool can_free = false;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1127) rcu_read_unlock();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1128) d_shrink_del(dentry);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1129) if (dentry->d_lockref.count < 0)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1130) can_free = dentry->d_flags & DCACHE_MAY_FREE;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1131) spin_unlock(&dentry->d_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1132) if (can_free)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1133) dentry_free(dentry);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1134) continue;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1135) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1136) rcu_read_unlock();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1137) d_shrink_del(dentry);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1138) parent = dentry->d_parent;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1139) if (parent != dentry)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1140) __dput_to_list(parent, list);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1141) __dentry_kill(dentry);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1142) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1143) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1144)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1145) static enum lru_status dentry_lru_isolate(struct list_head *item,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1146) struct list_lru_one *lru, spinlock_t *lru_lock, void *arg)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1147) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1148) struct list_head *freeable = arg;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1149) struct dentry *dentry = container_of(item, struct dentry, d_lru);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1150)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1151)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1152) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1153) * we are inverting the lru lock/dentry->d_lock here,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1154) * so use a trylock. If we fail to get the lock, just skip
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1155) * it
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1156) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1157) if (!spin_trylock(&dentry->d_lock))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1158) return LRU_SKIP;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1159)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1160) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1161) * Referenced dentries are still in use. If they have active
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1162) * counts, just remove them from the LRU. Otherwise give them
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1163) * another pass through the LRU.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1164) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1165) if (dentry->d_lockref.count) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1166) d_lru_isolate(lru, dentry);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1167) spin_unlock(&dentry->d_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1168) return LRU_REMOVED;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1169) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1170)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1171) if (dentry->d_flags & DCACHE_REFERENCED) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1172) dentry->d_flags &= ~DCACHE_REFERENCED;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1173) spin_unlock(&dentry->d_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1174)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1175) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1176) * The list move itself will be made by the common LRU code. At
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1177) * this point, we've dropped the dentry->d_lock but keep the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1178) * lru lock. This is safe to do, since every list movement is
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1179) * protected by the lru lock even if both locks are held.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1180) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1181) * This is guaranteed by the fact that all LRU management
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1182) * functions are intermediated by the LRU API calls like
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1183) * list_lru_add and list_lru_del. List movement in this file
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1184) * only ever occur through this functions or through callbacks
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1185) * like this one, that are called from the LRU API.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1186) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1187) * The only exceptions to this are functions like
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1188) * shrink_dentry_list, and code that first checks for the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1189) * DCACHE_SHRINK_LIST flag. Those are guaranteed to be
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1190) * operating only with stack provided lists after they are
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1191) * properly isolated from the main list. It is thus, always a
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1192) * local access.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1193) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1194) return LRU_ROTATE;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1195) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1196)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1197) d_lru_shrink_move(lru, dentry, freeable);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1198) spin_unlock(&dentry->d_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1199)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1200) return LRU_REMOVED;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1201) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1202)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1203) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1204) * prune_dcache_sb - shrink the dcache
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1205) * @sb: superblock
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1206) * @sc: shrink control, passed to list_lru_shrink_walk()
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1207) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1208) * Attempt to shrink the superblock dcache LRU by @sc->nr_to_scan entries. This
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1209) * is done when we need more memory and called from the superblock shrinker
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1210) * function.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1211) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1212) * This function may fail to free any resources if all the dentries are in
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1213) * use.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1214) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1215) long prune_dcache_sb(struct super_block *sb, struct shrink_control *sc)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1216) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1217) LIST_HEAD(dispose);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1218) long freed;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1219)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1220) freed = list_lru_shrink_walk(&sb->s_dentry_lru, sc,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1221) dentry_lru_isolate, &dispose);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1222) shrink_dentry_list(&dispose);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1223) return freed;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1224) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1225)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1226) static enum lru_status dentry_lru_isolate_shrink(struct list_head *item,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1227) struct list_lru_one *lru, spinlock_t *lru_lock, void *arg)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1228) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1229) struct list_head *freeable = arg;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1230) struct dentry *dentry = container_of(item, struct dentry, d_lru);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1231)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1232) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1233) * we are inverting the lru lock/dentry->d_lock here,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1234) * so use a trylock. If we fail to get the lock, just skip
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1235) * it
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1236) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1237) if (!spin_trylock(&dentry->d_lock))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1238) return LRU_SKIP;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1239)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1240) d_lru_shrink_move(lru, dentry, freeable);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1241) spin_unlock(&dentry->d_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1242)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1243) return LRU_REMOVED;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1244) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1245)
^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) * shrink_dcache_sb - shrink dcache for a superblock
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1249) * @sb: superblock
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1250) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1251) * Shrink the dcache for the specified super block. This is used to free
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1252) * the dcache before unmounting a file system.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1253) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1254) void shrink_dcache_sb(struct super_block *sb)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1255) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1256) do {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1257) LIST_HEAD(dispose);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1258)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1259) list_lru_walk(&sb->s_dentry_lru,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1260) dentry_lru_isolate_shrink, &dispose, 1024);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1261) shrink_dentry_list(&dispose);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1262) } while (list_lru_count(&sb->s_dentry_lru) > 0);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1263) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1264) EXPORT_SYMBOL(shrink_dcache_sb);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1265)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1266) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1267) * enum d_walk_ret - action to talke during tree walk
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1268) * @D_WALK_CONTINUE: contrinue walk
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1269) * @D_WALK_QUIT: quit walk
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1270) * @D_WALK_NORETRY: quit when retry is needed
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1271) * @D_WALK_SKIP: skip this dentry and its children
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1272) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1273) enum d_walk_ret {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1274) D_WALK_CONTINUE,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1275) D_WALK_QUIT,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1276) D_WALK_NORETRY,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1277) D_WALK_SKIP,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1278) };
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1279)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1280) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1281) * d_walk - walk the dentry tree
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1282) * @parent: start of walk
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1283) * @data: data passed to @enter() and @finish()
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1284) * @enter: callback when first entering the dentry
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1285) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1286) * The @enter() callbacks are called with d_lock held.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1287) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1288) static void d_walk(struct dentry *parent, void *data,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1289) enum d_walk_ret (*enter)(void *, struct dentry *))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1290) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1291) struct dentry *this_parent;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1292) struct list_head *next;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1293) unsigned seq = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1294) enum d_walk_ret ret;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1295) bool retry = true;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1296)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1297) again:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1298) read_seqbegin_or_lock(&rename_lock, &seq);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1299) this_parent = parent;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1300) spin_lock(&this_parent->d_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1301)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1302) ret = enter(data, this_parent);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1303) switch (ret) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1304) case D_WALK_CONTINUE:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1305) break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1306) case D_WALK_QUIT:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1307) case D_WALK_SKIP:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1308) goto out_unlock;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1309) case D_WALK_NORETRY:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1310) retry = false;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1311) break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1312) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1313) repeat:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1314) next = this_parent->d_subdirs.next;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1315) resume:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1316) while (next != &this_parent->d_subdirs) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1317) struct list_head *tmp = next;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1318) struct dentry *dentry = list_entry(tmp, struct dentry, d_child);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1319) next = tmp->next;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1320)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1321) if (unlikely(dentry->d_flags & DCACHE_DENTRY_CURSOR))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1322) continue;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1323)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1324) spin_lock_nested(&dentry->d_lock, DENTRY_D_LOCK_NESTED);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1325)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1326) ret = enter(data, dentry);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1327) switch (ret) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1328) case D_WALK_CONTINUE:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1329) break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1330) case D_WALK_QUIT:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1331) spin_unlock(&dentry->d_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1332) goto out_unlock;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1333) case D_WALK_NORETRY:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1334) retry = false;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1335) break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1336) case D_WALK_SKIP:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1337) spin_unlock(&dentry->d_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1338) continue;
^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) if (!list_empty(&dentry->d_subdirs)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1342) spin_unlock(&this_parent->d_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1343) spin_release(&dentry->d_lock.dep_map, _RET_IP_);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1344) this_parent = dentry;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1345) spin_acquire(&this_parent->d_lock.dep_map, 0, 1, _RET_IP_);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1346) goto repeat;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1347) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1348) spin_unlock(&dentry->d_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1349) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1350) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1351) * All done at this level ... ascend and resume the search.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1352) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1353) rcu_read_lock();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1354) ascend:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1355) if (this_parent != parent) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1356) struct dentry *child = this_parent;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1357) this_parent = child->d_parent;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1358)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1359) spin_unlock(&child->d_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1360) spin_lock(&this_parent->d_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1361)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1362) /* might go back up the wrong parent if we have had a rename. */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1363) if (need_seqretry(&rename_lock, seq))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1364) goto rename_retry;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1365) /* go into the first sibling still alive */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1366) do {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1367) next = child->d_child.next;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1368) if (next == &this_parent->d_subdirs)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1369) goto ascend;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1370) child = list_entry(next, struct dentry, d_child);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1371) } while (unlikely(child->d_flags & DCACHE_DENTRY_KILLED));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1372) rcu_read_unlock();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1373) goto resume;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1374) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1375) if (need_seqretry(&rename_lock, seq))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1376) goto rename_retry;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1377) rcu_read_unlock();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1378)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1379) out_unlock:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1380) spin_unlock(&this_parent->d_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1381) done_seqretry(&rename_lock, seq);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1382) return;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1383)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1384) rename_retry:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1385) spin_unlock(&this_parent->d_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1386) rcu_read_unlock();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1387) BUG_ON(seq & 1);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1388) if (!retry)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1389) return;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1390) seq = 1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1391) goto again;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1392) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1393)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1394) struct check_mount {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1395) struct vfsmount *mnt;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1396) unsigned int mounted;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1397) };
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1398)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1399) static enum d_walk_ret path_check_mount(void *data, struct dentry *dentry)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1400) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1401) struct check_mount *info = data;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1402) struct path path = { .mnt = info->mnt, .dentry = dentry };
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1403)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1404) if (likely(!d_mountpoint(dentry)))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1405) return D_WALK_CONTINUE;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1406) if (__path_is_mountpoint(&path)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1407) info->mounted = 1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1408) return D_WALK_QUIT;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1409) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1410) return D_WALK_CONTINUE;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1411) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1412)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1413) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1414) * path_has_submounts - check for mounts over a dentry in the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1415) * current namespace.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1416) * @parent: path to check.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1417) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1418) * Return true if the parent or its subdirectories contain
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1419) * a mount point in the current namespace.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1420) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1421) int path_has_submounts(const struct path *parent)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1422) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1423) struct check_mount data = { .mnt = parent->mnt, .mounted = 0 };
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1424)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1425) read_seqlock_excl(&mount_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1426) d_walk(parent->dentry, &data, path_check_mount);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1427) read_sequnlock_excl(&mount_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1428)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1429) return data.mounted;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1430) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1431) EXPORT_SYMBOL(path_has_submounts);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1432)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1433) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1434) * Called by mount code to set a mountpoint and check if the mountpoint is
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1435) * reachable (e.g. NFS can unhash a directory dentry and then the complete
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1436) * subtree can become unreachable).
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1437) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1438) * Only one of d_invalidate() and d_set_mounted() must succeed. For
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1439) * this reason take rename_lock and d_lock on dentry and ancestors.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1440) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1441) int d_set_mounted(struct dentry *dentry)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1442) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1443) struct dentry *p;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1444) int ret = -ENOENT;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1445) write_seqlock(&rename_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1446) for (p = dentry->d_parent; !IS_ROOT(p); p = p->d_parent) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1447) /* Need exclusion wrt. d_invalidate() */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1448) spin_lock(&p->d_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1449) if (unlikely(d_unhashed(p))) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1450) spin_unlock(&p->d_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1451) goto out;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1452) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1453) spin_unlock(&p->d_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1454) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1455) spin_lock(&dentry->d_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1456) if (!d_unlinked(dentry)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1457) ret = -EBUSY;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1458) if (!d_mountpoint(dentry)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1459) dentry->d_flags |= DCACHE_MOUNTED;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1460) ret = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1461) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1462) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1463) spin_unlock(&dentry->d_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1464) out:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1465) write_sequnlock(&rename_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1466) return ret;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1467) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1468)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1469) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1470) * Search the dentry child list of the specified parent,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1471) * and move any unused dentries to the end of the unused
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1472) * list for prune_dcache(). We descend to the next level
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1473) * whenever the d_subdirs list is non-empty and continue
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1474) * searching.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1475) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1476) * It returns zero iff there are no unused children,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1477) * otherwise it returns the number of children moved to
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1478) * the end of the unused list. This may not be the total
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1479) * number of unused children, because select_parent can
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1480) * drop the lock and return early due to latency
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1481) * constraints.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1482) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1483)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1484) struct select_data {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1485) struct dentry *start;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1486) union {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1487) long found;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1488) struct dentry *victim;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1489) };
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1490) struct list_head dispose;
^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) static enum d_walk_ret select_collect(void *_data, struct dentry *dentry)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1494) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1495) struct select_data *data = _data;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1496) enum d_walk_ret ret = D_WALK_CONTINUE;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1497)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1498) if (data->start == dentry)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1499) goto out;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1500)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1501) if (dentry->d_flags & DCACHE_SHRINK_LIST) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1502) data->found++;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1503) } else {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1504) if (dentry->d_flags & DCACHE_LRU_LIST)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1505) d_lru_del(dentry);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1506) if (!dentry->d_lockref.count) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1507) d_shrink_add(dentry, &data->dispose);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1508) data->found++;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1509) }
^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) * We can return to the caller if we have found some (this
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1513) * ensures forward progress). We'll be coming back to find
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1514) * the rest.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1515) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1516) if (!list_empty(&data->dispose))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1517) ret = need_resched() ? D_WALK_QUIT : D_WALK_NORETRY;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1518) out:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1519) return ret;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1520) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1521)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1522) static enum d_walk_ret select_collect2(void *_data, struct dentry *dentry)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1523) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1524) struct select_data *data = _data;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1525) enum d_walk_ret ret = D_WALK_CONTINUE;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1526)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1527) if (data->start == dentry)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1528) goto out;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1529)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1530) if (dentry->d_flags & DCACHE_SHRINK_LIST) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1531) if (!dentry->d_lockref.count) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1532) rcu_read_lock();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1533) data->victim = dentry;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1534) return D_WALK_QUIT;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1535) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1536) } else {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1537) if (dentry->d_flags & DCACHE_LRU_LIST)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1538) d_lru_del(dentry);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1539) if (!dentry->d_lockref.count)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1540) d_shrink_add(dentry, &data->dispose);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1541) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1542) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1543) * We can return to the caller if we have found some (this
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1544) * ensures forward progress). We'll be coming back to find
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1545) * the rest.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1546) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1547) if (!list_empty(&data->dispose))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1548) ret = need_resched() ? D_WALK_QUIT : D_WALK_NORETRY;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1549) out:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1550) return ret;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1551) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1552)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1553) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1554) * shrink_dcache_parent - prune dcache
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1555) * @parent: parent of entries to prune
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1556) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1557) * Prune the dcache to remove unused children of the parent dentry.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1558) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1559) void shrink_dcache_parent(struct dentry *parent)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1560) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1561) for (;;) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1562) struct select_data data = {.start = parent};
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1563)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1564) INIT_LIST_HEAD(&data.dispose);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1565) d_walk(parent, &data, select_collect);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1566)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1567) if (!list_empty(&data.dispose)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1568) shrink_dentry_list(&data.dispose);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1569) continue;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1570) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1571)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1572) cond_resched();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1573) if (!data.found)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1574) break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1575) data.victim = NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1576) d_walk(parent, &data, select_collect2);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1577) if (data.victim) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1578) struct dentry *parent;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1579) spin_lock(&data.victim->d_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1580) if (!shrink_lock_dentry(data.victim)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1581) spin_unlock(&data.victim->d_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1582) rcu_read_unlock();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1583) } else {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1584) rcu_read_unlock();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1585) parent = data.victim->d_parent;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1586) if (parent != data.victim)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1587) __dput_to_list(parent, &data.dispose);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1588) __dentry_kill(data.victim);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1589) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1590) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1591) if (!list_empty(&data.dispose))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1592) shrink_dentry_list(&data.dispose);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1593) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1594) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1595) EXPORT_SYMBOL(shrink_dcache_parent);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1596)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1597) static enum d_walk_ret umount_check(void *_data, struct dentry *dentry)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1598) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1599) /* it has busy descendents; complain about those instead */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1600) if (!list_empty(&dentry->d_subdirs))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1601) return D_WALK_CONTINUE;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1602)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1603) /* root with refcount 1 is fine */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1604) if (dentry == _data && dentry->d_lockref.count == 1)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1605) return D_WALK_CONTINUE;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1606)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1607) printk(KERN_ERR "BUG: Dentry %p{i=%lx,n=%pd} "
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1608) " still in use (%d) [unmount of %s %s]\n",
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1609) dentry,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1610) dentry->d_inode ?
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1611) dentry->d_inode->i_ino : 0UL,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1612) dentry,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1613) dentry->d_lockref.count,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1614) dentry->d_sb->s_type->name,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1615) dentry->d_sb->s_id);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1616) WARN_ON(1);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1617) return D_WALK_CONTINUE;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1618) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1619)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1620) static void do_one_tree(struct dentry *dentry)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1621) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1622) shrink_dcache_parent(dentry);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1623) d_walk(dentry, dentry, umount_check);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1624) d_drop(dentry);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1625) dput(dentry);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1626) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1627)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1628) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1629) * destroy the dentries attached to a superblock on unmounting
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1630) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1631) void shrink_dcache_for_umount(struct super_block *sb)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1632) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1633) struct dentry *dentry;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1634)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1635) WARN(down_read_trylock(&sb->s_umount), "s_umount should've been locked");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1636)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1637) dentry = sb->s_root;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1638) sb->s_root = NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1639) do_one_tree(dentry);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1640)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1641) while (!hlist_bl_empty(&sb->s_roots)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1642) dentry = dget(hlist_bl_entry(hlist_bl_first(&sb->s_roots), struct dentry, d_hash));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1643) do_one_tree(dentry);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1644) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1645) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1646)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1647) static enum d_walk_ret find_submount(void *_data, struct dentry *dentry)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1648) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1649) struct dentry **victim = _data;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1650) if (d_mountpoint(dentry)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1651) __dget_dlock(dentry);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1652) *victim = dentry;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1653) return D_WALK_QUIT;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1654) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1655) return D_WALK_CONTINUE;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1656) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1657)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1658) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1659) * d_invalidate - detach submounts, prune dcache, and drop
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1660) * @dentry: dentry to invalidate (aka detach, prune and drop)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1661) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1662) void d_invalidate(struct dentry *dentry)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1663) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1664) bool had_submounts = false;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1665) spin_lock(&dentry->d_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1666) if (d_unhashed(dentry)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1667) spin_unlock(&dentry->d_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1668) return;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1669) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1670) __d_drop(dentry);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1671) spin_unlock(&dentry->d_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1672)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1673) /* Negative dentries can be dropped without further checks */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1674) if (!dentry->d_inode)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1675) return;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1676)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1677) shrink_dcache_parent(dentry);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1678) for (;;) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1679) struct dentry *victim = NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1680) d_walk(dentry, &victim, find_submount);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1681) if (!victim) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1682) if (had_submounts)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1683) shrink_dcache_parent(dentry);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1684) return;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1685) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1686) had_submounts = true;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1687) detach_mounts(victim);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1688) dput(victim);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1689) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1690) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1691) EXPORT_SYMBOL(d_invalidate);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1692)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1693) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1694) * __d_alloc - allocate a dcache entry
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1695) * @sb: filesystem it will belong to
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1696) * @name: qstr of the name
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1697) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1698) * Allocates a dentry. It returns %NULL if there is insufficient memory
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1699) * available. On a success the dentry is returned. The name passed in is
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1700) * copied and the copy passed in may be reused after this call.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1701) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1702)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1703) static struct dentry *__d_alloc(struct super_block *sb, const struct qstr *name)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1704) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1705) struct dentry *dentry;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1706) char *dname;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1707) int err;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1708)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1709) dentry = kmem_cache_alloc(dentry_cache, GFP_KERNEL);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1710) if (!dentry)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1711) return NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1712)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1713) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1714) * We guarantee that the inline name is always NUL-terminated.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1715) * This way the memcpy() done by the name switching in rename
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1716) * will still always have a NUL at the end, even if we might
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1717) * be overwriting an internal NUL character
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1718) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1719) dentry->d_iname[DNAME_INLINE_LEN-1] = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1720) if (unlikely(!name)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1721) name = &slash_name;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1722) dname = dentry->d_iname;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1723) } else if (name->len > DNAME_INLINE_LEN-1) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1724) size_t size = offsetof(struct external_name, name[1]);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1725) struct external_name *p = kmalloc(size + name->len,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1726) GFP_KERNEL_ACCOUNT |
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1727) __GFP_RECLAIMABLE);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1728) if (!p) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1729) kmem_cache_free(dentry_cache, dentry);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1730) return NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1731) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1732) atomic_set(&p->u.count, 1);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1733) dname = p->name;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1734) } else {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1735) dname = dentry->d_iname;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1736) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1737)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1738) dentry->d_name.len = name->len;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1739) dentry->d_name.hash = name->hash;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1740) memcpy(dname, name->name, name->len);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1741) dname[name->len] = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1742)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1743) /* Make sure we always see the terminating NUL character */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1744) smp_store_release(&dentry->d_name.name, dname); /* ^^^ */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1745)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1746) dentry->d_lockref.count = 1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1747) dentry->d_flags = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1748) spin_lock_init(&dentry->d_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1749) seqcount_spinlock_init(&dentry->d_seq, &dentry->d_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1750) dentry->d_inode = NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1751) dentry->d_parent = dentry;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1752) dentry->d_sb = sb;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1753) dentry->d_op = NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1754) dentry->d_fsdata = NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1755) INIT_HLIST_BL_NODE(&dentry->d_hash);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1756) INIT_LIST_HEAD(&dentry->d_lru);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1757) INIT_LIST_HEAD(&dentry->d_subdirs);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1758) INIT_HLIST_NODE(&dentry->d_u.d_alias);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1759) INIT_LIST_HEAD(&dentry->d_child);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1760) d_set_d_op(dentry, dentry->d_sb->s_d_op);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1761)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1762) if (dentry->d_op && dentry->d_op->d_init) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1763) err = dentry->d_op->d_init(dentry);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1764) if (err) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1765) if (dname_external(dentry))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1766) kfree(external_name(dentry));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1767) kmem_cache_free(dentry_cache, dentry);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1768) return NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1769) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1770) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1771)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1772) this_cpu_inc(nr_dentry);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1773)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1774) return dentry;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1775) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1776)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1777) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1778) * d_alloc - allocate a dcache entry
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1779) * @parent: parent of entry to allocate
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1780) * @name: qstr of the name
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1781) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1782) * Allocates a dentry. It returns %NULL if there is insufficient memory
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1783) * available. On a success the dentry is returned. The name passed in is
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1784) * copied and the copy passed in may be reused after this call.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1785) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1786) struct dentry *d_alloc(struct dentry * parent, const struct qstr *name)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1787) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1788) struct dentry *dentry = __d_alloc(parent->d_sb, name);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1789) if (!dentry)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1790) return NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1791) spin_lock(&parent->d_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1792) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1793) * don't need child lock because it is not subject
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1794) * to concurrency here
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1795) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1796) __dget_dlock(parent);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1797) dentry->d_parent = parent;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1798) list_add(&dentry->d_child, &parent->d_subdirs);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1799) spin_unlock(&parent->d_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1800)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1801) return dentry;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1802) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1803) EXPORT_SYMBOL(d_alloc);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1804)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1805) struct dentry *d_alloc_anon(struct super_block *sb)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1806) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1807) return __d_alloc(sb, NULL);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1808) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1809) EXPORT_SYMBOL(d_alloc_anon);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1810)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1811) struct dentry *d_alloc_cursor(struct dentry * parent)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1812) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1813) struct dentry *dentry = d_alloc_anon(parent->d_sb);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1814) if (dentry) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1815) dentry->d_flags |= DCACHE_DENTRY_CURSOR;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1816) dentry->d_parent = dget(parent);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1817) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1818) return dentry;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1819) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1820)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1821) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1822) * d_alloc_pseudo - allocate a dentry (for lookup-less filesystems)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1823) * @sb: the superblock
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1824) * @name: qstr of the name
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1825) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1826) * For a filesystem that just pins its dentries in memory and never
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1827) * performs lookups at all, return an unhashed IS_ROOT dentry.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1828) * This is used for pipes, sockets et.al. - the stuff that should
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1829) * never be anyone's children or parents. Unlike all other
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1830) * dentries, these will not have RCU delay between dropping the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1831) * last reference and freeing them.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1832) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1833) * The only user is alloc_file_pseudo() and that's what should
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1834) * be considered a public interface. Don't use directly.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1835) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1836) struct dentry *d_alloc_pseudo(struct super_block *sb, const struct qstr *name)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1837) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1838) struct dentry *dentry = __d_alloc(sb, name);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1839) if (likely(dentry))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1840) dentry->d_flags |= DCACHE_NORCU;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1841) return dentry;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1842) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1843)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1844) struct dentry *d_alloc_name(struct dentry *parent, const char *name)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1845) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1846) struct qstr q;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1847)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1848) q.name = name;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1849) q.hash_len = hashlen_string(parent, name);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1850) return d_alloc(parent, &q);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1851) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1852) EXPORT_SYMBOL(d_alloc_name);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1853)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1854) void d_set_d_op(struct dentry *dentry, const struct dentry_operations *op)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1855) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1856) WARN_ON_ONCE(dentry->d_op);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1857) WARN_ON_ONCE(dentry->d_flags & (DCACHE_OP_HASH |
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1858) DCACHE_OP_COMPARE |
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1859) DCACHE_OP_REVALIDATE |
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1860) DCACHE_OP_WEAK_REVALIDATE |
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1861) DCACHE_OP_DELETE |
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1862) DCACHE_OP_REAL));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1863) dentry->d_op = op;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1864) if (!op)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1865) return;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1866) if (op->d_hash)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1867) dentry->d_flags |= DCACHE_OP_HASH;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1868) if (op->d_compare)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1869) dentry->d_flags |= DCACHE_OP_COMPARE;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1870) if (op->d_revalidate)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1871) dentry->d_flags |= DCACHE_OP_REVALIDATE;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1872) if (op->d_weak_revalidate)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1873) dentry->d_flags |= DCACHE_OP_WEAK_REVALIDATE;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1874) if (op->d_delete)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1875) dentry->d_flags |= DCACHE_OP_DELETE;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1876) if (op->d_prune)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1877) dentry->d_flags |= DCACHE_OP_PRUNE;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1878) if (op->d_real)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1879) dentry->d_flags |= DCACHE_OP_REAL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1880)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1881) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1882) EXPORT_SYMBOL(d_set_d_op);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1883)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1884)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1885) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1886) * d_set_fallthru - Mark a dentry as falling through to a lower layer
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1887) * @dentry - The dentry to mark
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1888) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1889) * Mark a dentry as falling through to the lower layer (as set with
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1890) * d_pin_lower()). This flag may be recorded on the medium.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1891) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1892) void d_set_fallthru(struct dentry *dentry)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1893) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1894) spin_lock(&dentry->d_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1895) dentry->d_flags |= DCACHE_FALLTHRU;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1896) spin_unlock(&dentry->d_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1897) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1898) EXPORT_SYMBOL(d_set_fallthru);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1899)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1900) static unsigned d_flags_for_inode(struct inode *inode)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1901) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1902) unsigned add_flags = DCACHE_REGULAR_TYPE;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1903)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1904) if (!inode)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1905) return DCACHE_MISS_TYPE;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1906)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1907) if (S_ISDIR(inode->i_mode)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1908) add_flags = DCACHE_DIRECTORY_TYPE;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1909) if (unlikely(!(inode->i_opflags & IOP_LOOKUP))) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1910) if (unlikely(!inode->i_op->lookup))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1911) add_flags = DCACHE_AUTODIR_TYPE;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1912) else
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1913) inode->i_opflags |= IOP_LOOKUP;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1914) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1915) goto type_determined;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1916) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1917)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1918) if (unlikely(!(inode->i_opflags & IOP_NOFOLLOW))) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1919) if (unlikely(inode->i_op->get_link)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1920) add_flags = DCACHE_SYMLINK_TYPE;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1921) goto type_determined;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1922) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1923) inode->i_opflags |= IOP_NOFOLLOW;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1924) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1925)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1926) if (unlikely(!S_ISREG(inode->i_mode)))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1927) add_flags = DCACHE_SPECIAL_TYPE;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1928)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1929) type_determined:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1930) if (unlikely(IS_AUTOMOUNT(inode)))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1931) add_flags |= DCACHE_NEED_AUTOMOUNT;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1932) return add_flags;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1933) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1934)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1935) static void __d_instantiate(struct dentry *dentry, struct inode *inode)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1936) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1937) unsigned add_flags = d_flags_for_inode(inode);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1938) WARN_ON(d_in_lookup(dentry));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1939)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1940) spin_lock(&dentry->d_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1941) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1942) * Decrement negative dentry count if it was in the LRU list.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1943) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1944) if (dentry->d_flags & DCACHE_LRU_LIST)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1945) this_cpu_dec(nr_dentry_negative);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1946) hlist_add_head(&dentry->d_u.d_alias, &inode->i_dentry);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1947) raw_write_seqcount_begin(&dentry->d_seq);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1948) __d_set_inode_and_type(dentry, inode, add_flags);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1949) raw_write_seqcount_end(&dentry->d_seq);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1950) fsnotify_update_flags(dentry);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1951) spin_unlock(&dentry->d_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1952) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1953)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1954) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1955) * d_instantiate - fill in inode information for a dentry
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1956) * @entry: dentry to complete
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1957) * @inode: inode to attach to this dentry
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1958) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1959) * Fill in inode information in the entry.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1960) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1961) * This turns negative dentries into productive full members
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1962) * of society.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1963) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1964) * NOTE! This assumes that the inode count has been incremented
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1965) * (or otherwise set) by the caller to indicate that it is now
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1966) * in use by the dcache.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1967) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1968)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1969) void d_instantiate(struct dentry *entry, struct inode * inode)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1970) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1971) BUG_ON(!hlist_unhashed(&entry->d_u.d_alias));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1972) if (inode) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1973) security_d_instantiate(entry, inode);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1974) spin_lock(&inode->i_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1975) __d_instantiate(entry, inode);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1976) spin_unlock(&inode->i_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1977) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1978) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1979) EXPORT_SYMBOL(d_instantiate);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1980)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1981) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1982) * This should be equivalent to d_instantiate() + unlock_new_inode(),
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1983) * with lockdep-related part of unlock_new_inode() done before
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1984) * anything else. Use that instead of open-coding d_instantiate()/
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1985) * unlock_new_inode() combinations.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1986) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1987) void d_instantiate_new(struct dentry *entry, struct inode *inode)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1988) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1989) BUG_ON(!hlist_unhashed(&entry->d_u.d_alias));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1990) BUG_ON(!inode);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1991) lockdep_annotate_inode_mutex_key(inode);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1992) security_d_instantiate(entry, inode);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1993) spin_lock(&inode->i_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1994) __d_instantiate(entry, inode);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1995) WARN_ON(!(inode->i_state & I_NEW));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1996) inode->i_state &= ~I_NEW & ~I_CREATING;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1997) smp_mb();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1998) wake_up_bit(&inode->i_state, __I_NEW);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1999) spin_unlock(&inode->i_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2000) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2001) EXPORT_SYMBOL(d_instantiate_new);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2002)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2003) struct dentry *d_make_root(struct inode *root_inode)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2004) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2005) struct dentry *res = NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2006)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2007) if (root_inode) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2008) res = d_alloc_anon(root_inode->i_sb);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2009) if (res)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2010) d_instantiate(res, root_inode);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2011) else
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2012) iput(root_inode);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2013) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2014) return res;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2015) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2016) EXPORT_SYMBOL(d_make_root);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2017)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2018) static struct dentry *__d_instantiate_anon(struct dentry *dentry,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2019) struct inode *inode,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2020) bool disconnected)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2021) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2022) struct dentry *res;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2023) unsigned add_flags;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2024)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2025) security_d_instantiate(dentry, inode);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2026) spin_lock(&inode->i_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2027) res = __d_find_any_alias(inode);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2028) if (res) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2029) spin_unlock(&inode->i_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2030) dput(dentry);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2031) goto out_iput;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2032) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2033)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2034) /* attach a disconnected dentry */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2035) add_flags = d_flags_for_inode(inode);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2036)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2037) if (disconnected)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2038) add_flags |= DCACHE_DISCONNECTED;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2039)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2040) spin_lock(&dentry->d_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2041) __d_set_inode_and_type(dentry, inode, add_flags);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2042) hlist_add_head(&dentry->d_u.d_alias, &inode->i_dentry);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2043) if (!disconnected) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2044) hlist_bl_lock(&dentry->d_sb->s_roots);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2045) hlist_bl_add_head(&dentry->d_hash, &dentry->d_sb->s_roots);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2046) hlist_bl_unlock(&dentry->d_sb->s_roots);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2047) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2048) spin_unlock(&dentry->d_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2049) spin_unlock(&inode->i_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2050)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2051) return dentry;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2052)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2053) out_iput:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2054) iput(inode);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2055) return res;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2056) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2057)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2058) struct dentry *d_instantiate_anon(struct dentry *dentry, struct inode *inode)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2059) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2060) return __d_instantiate_anon(dentry, inode, true);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2061) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2062) EXPORT_SYMBOL(d_instantiate_anon);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2063)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2064) static struct dentry *__d_obtain_alias(struct inode *inode, bool disconnected)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2065) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2066) struct dentry *tmp;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2067) struct dentry *res;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2068)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2069) if (!inode)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2070) return ERR_PTR(-ESTALE);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2071) if (IS_ERR(inode))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2072) return ERR_CAST(inode);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2073)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2074) res = d_find_any_alias(inode);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2075) if (res)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2076) goto out_iput;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2077)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2078) tmp = d_alloc_anon(inode->i_sb);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2079) if (!tmp) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2080) res = ERR_PTR(-ENOMEM);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2081) goto out_iput;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2082) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2083)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2084) return __d_instantiate_anon(tmp, inode, disconnected);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2085)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2086) out_iput:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2087) iput(inode);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2088) return res;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2089) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2090)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2091) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2092) * d_obtain_alias - find or allocate a DISCONNECTED dentry for a given inode
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2093) * @inode: inode to allocate the dentry for
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2094) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2095) * Obtain a dentry for an inode resulting from NFS filehandle conversion or
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2096) * similar open by handle operations. The returned dentry may be anonymous,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2097) * or may have a full name (if the inode was already in the cache).
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2098) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2099) * When called on a directory inode, we must ensure that the inode only ever
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2100) * has one dentry. If a dentry is found, that is returned instead of
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2101) * allocating a new one.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2102) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2103) * On successful return, the reference to the inode has been transferred
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2104) * to the dentry. In case of an error the reference on the inode is released.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2105) * To make it easier to use in export operations a %NULL or IS_ERR inode may
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2106) * be passed in and the error will be propagated to the return value,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2107) * with a %NULL @inode replaced by ERR_PTR(-ESTALE).
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2108) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2109) struct dentry *d_obtain_alias(struct inode *inode)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2110) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2111) return __d_obtain_alias(inode, true);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2112) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2113) EXPORT_SYMBOL_NS(d_obtain_alias, ANDROID_GKI_VFS_EXPORT_ONLY);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2114)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2115) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2116) * d_obtain_root - find or allocate a dentry for a given inode
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2117) * @inode: inode to allocate the dentry for
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2118) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2119) * Obtain an IS_ROOT dentry for the root of a filesystem.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2120) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2121) * We must ensure that directory inodes only ever have one dentry. If a
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2122) * dentry is found, that is returned instead of allocating a new one.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2123) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2124) * On successful return, the reference to the inode has been transferred
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2125) * to the dentry. In case of an error the reference on the inode is
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2126) * released. A %NULL or IS_ERR inode may be passed in and will be the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2127) * error will be propagate to the return value, with a %NULL @inode
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2128) * replaced by ERR_PTR(-ESTALE).
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2129) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2130) struct dentry *d_obtain_root(struct inode *inode)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2131) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2132) return __d_obtain_alias(inode, false);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2133) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2134) EXPORT_SYMBOL(d_obtain_root);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2135)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2136) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2137) * d_add_ci - lookup or allocate new dentry with case-exact name
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2138) * @inode: the inode case-insensitive lookup has found
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2139) * @dentry: the negative dentry that was passed to the parent's lookup func
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2140) * @name: the case-exact name to be associated with the returned dentry
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2141) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2142) * This is to avoid filling the dcache with case-insensitive names to the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2143) * same inode, only the actual correct case is stored in the dcache for
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2144) * case-insensitive filesystems.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2145) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2146) * For a case-insensitive lookup match and if the the case-exact dentry
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2147) * already exists in in the dcache, use it and return it.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2148) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2149) * If no entry exists with the exact case name, allocate new dentry with
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2150) * the exact case, and return the spliced entry.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2151) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2152) struct dentry *d_add_ci(struct dentry *dentry, struct inode *inode,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2153) struct qstr *name)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2154) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2155) struct dentry *found, *res;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2156)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2157) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2158) * First check if a dentry matching the name already exists,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2159) * if not go ahead and create it now.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2160) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2161) found = d_hash_and_lookup(dentry->d_parent, name);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2162) if (found) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2163) iput(inode);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2164) return found;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2165) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2166) if (d_in_lookup(dentry)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2167) found = d_alloc_parallel(dentry->d_parent, name,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2168) dentry->d_wait);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2169) if (IS_ERR(found) || !d_in_lookup(found)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2170) iput(inode);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2171) return found;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2172) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2173) } else {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2174) found = d_alloc(dentry->d_parent, name);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2175) if (!found) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2176) iput(inode);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2177) return ERR_PTR(-ENOMEM);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2178) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2179) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2180) res = d_splice_alias(inode, found);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2181) if (res) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2182) dput(found);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2183) return res;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2184) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2185) return found;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2186) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2187) EXPORT_SYMBOL_NS(d_add_ci, ANDROID_GKI_VFS_EXPORT_ONLY);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2188)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2189)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2190) static inline bool d_same_name(const struct dentry *dentry,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2191) const struct dentry *parent,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2192) const struct qstr *name)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2193) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2194) if (likely(!(parent->d_flags & DCACHE_OP_COMPARE))) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2195) if (dentry->d_name.len != name->len)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2196) return false;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2197) return dentry_cmp(dentry, name->name, name->len) == 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2198) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2199) return parent->d_op->d_compare(dentry,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2200) dentry->d_name.len, dentry->d_name.name,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2201) name) == 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2202) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2203)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2204) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2205) * __d_lookup_rcu - search for a dentry (racy, store-free)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2206) * @parent: parent dentry
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2207) * @name: qstr of name we wish to find
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2208) * @seqp: returns d_seq value at the point where the dentry was found
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2209) * Returns: dentry, or NULL
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2210) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2211) * __d_lookup_rcu is the dcache lookup function for rcu-walk name
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2212) * resolution (store-free path walking) design described in
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2213) * Documentation/filesystems/path-lookup.txt.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2214) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2215) * This is not to be used outside core vfs.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2216) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2217) * __d_lookup_rcu must only be used in rcu-walk mode, ie. with vfsmount lock
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2218) * held, and rcu_read_lock held. The returned dentry must not be stored into
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2219) * without taking d_lock and checking d_seq sequence count against @seq
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2220) * returned here.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2221) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2222) * A refcount may be taken on the found dentry with the d_rcu_to_refcount
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2223) * function.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2224) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2225) * Alternatively, __d_lookup_rcu may be called again to look up the child of
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2226) * the returned dentry, so long as its parent's seqlock is checked after the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2227) * child is looked up. Thus, an interlocking stepping of sequence lock checks
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2228) * is formed, giving integrity down the path walk.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2229) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2230) * NOTE! The caller *has* to check the resulting dentry against the sequence
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2231) * number we've returned before using any of the resulting dentry state!
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2232) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2233) struct dentry *__d_lookup_rcu(const struct dentry *parent,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2234) const struct qstr *name,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2235) unsigned *seqp)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2236) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2237) u64 hashlen = name->hash_len;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2238) const unsigned char *str = name->name;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2239) struct hlist_bl_head *b = d_hash(hashlen_hash(hashlen));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2240) struct hlist_bl_node *node;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2241) struct dentry *dentry;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2242)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2243) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2244) * Note: There is significant duplication with __d_lookup_rcu which is
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2245) * required to prevent single threaded performance regressions
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2246) * especially on architectures where smp_rmb (in seqcounts) are costly.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2247) * Keep the two functions in sync.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2248) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2249)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2250) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2251) * The hash list is protected using RCU.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2252) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2253) * Carefully use d_seq when comparing a candidate dentry, to avoid
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2254) * races with d_move().
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2255) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2256) * It is possible that concurrent renames can mess up our list
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2257) * walk here and result in missing our dentry, resulting in the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2258) * false-negative result. d_lookup() protects against concurrent
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2259) * renames using rename_lock seqlock.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2260) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2261) * See Documentation/filesystems/path-lookup.txt for more details.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2262) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2263) hlist_bl_for_each_entry_rcu(dentry, node, b, d_hash) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2264) unsigned seq;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2265)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2266) seqretry:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2267) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2268) * The dentry sequence count protects us from concurrent
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2269) * renames, and thus protects parent and name fields.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2270) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2271) * The caller must perform a seqcount check in order
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2272) * to do anything useful with the returned dentry.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2273) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2274) * NOTE! We do a "raw" seqcount_begin here. That means that
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2275) * we don't wait for the sequence count to stabilize if it
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2276) * is in the middle of a sequence change. If we do the slow
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2277) * dentry compare, we will do seqretries until it is stable,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2278) * and if we end up with a successful lookup, we actually
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2279) * want to exit RCU lookup anyway.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2280) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2281) * Note that raw_seqcount_begin still *does* smp_rmb(), so
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2282) * we are still guaranteed NUL-termination of ->d_name.name.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2283) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2284) seq = raw_seqcount_begin(&dentry->d_seq);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2285) if (dentry->d_parent != parent)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2286) continue;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2287) if (d_unhashed(dentry))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2288) continue;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2289)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2290) if (unlikely(parent->d_flags & DCACHE_OP_COMPARE)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2291) int tlen;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2292) const char *tname;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2293) if (dentry->d_name.hash != hashlen_hash(hashlen))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2294) continue;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2295) tlen = dentry->d_name.len;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2296) tname = dentry->d_name.name;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2297) /* we want a consistent (name,len) pair */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2298) if (read_seqcount_retry(&dentry->d_seq, seq)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2299) cpu_relax();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2300) goto seqretry;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2301) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2302) if (parent->d_op->d_compare(dentry,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2303) tlen, tname, name) != 0)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2304) continue;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2305) } else {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2306) if (dentry->d_name.hash_len != hashlen)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2307) continue;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2308) if (dentry_cmp(dentry, str, hashlen_len(hashlen)) != 0)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2309) continue;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2310) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2311) *seqp = seq;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2312) return dentry;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2313) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2314) return NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2315) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2316)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2317) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2318) * d_lookup - search for a dentry
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2319) * @parent: parent dentry
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2320) * @name: qstr of name we wish to find
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2321) * Returns: dentry, or NULL
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2322) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2323) * d_lookup searches the children of the parent dentry for the name in
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2324) * question. If the dentry is found its reference count is incremented and the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2325) * dentry is returned. The caller must use dput to free the entry when it has
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2326) * finished using it. %NULL is returned if the dentry does not exist.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2327) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2328) struct dentry *d_lookup(const struct dentry *parent, const struct qstr *name)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2329) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2330) struct dentry *dentry;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2331) unsigned seq;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2332)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2333) do {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2334) seq = read_seqbegin(&rename_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2335) dentry = __d_lookup(parent, name);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2336) if (dentry)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2337) break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2338) } while (read_seqretry(&rename_lock, seq));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2339) return dentry;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2340) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2341) EXPORT_SYMBOL(d_lookup);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2342)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2343) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2344) * __d_lookup - search for a dentry (racy)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2345) * @parent: parent dentry
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2346) * @name: qstr of name we wish to find
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2347) * Returns: dentry, or NULL
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2348) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2349) * __d_lookup is like d_lookup, however it may (rarely) return a
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2350) * false-negative result due to unrelated rename activity.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2351) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2352) * __d_lookup is slightly faster by avoiding rename_lock read seqlock,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2353) * however it must be used carefully, eg. with a following d_lookup in
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2354) * the case of failure.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2355) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2356) * __d_lookup callers must be commented.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2357) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2358) struct dentry *__d_lookup(const struct dentry *parent, const struct qstr *name)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2359) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2360) unsigned int hash = name->hash;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2361) struct hlist_bl_head *b = d_hash(hash);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2362) struct hlist_bl_node *node;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2363) struct dentry *found = NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2364) struct dentry *dentry;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2365)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2366) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2367) * Note: There is significant duplication with __d_lookup_rcu which is
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2368) * required to prevent single threaded performance regressions
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2369) * especially on architectures where smp_rmb (in seqcounts) are costly.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2370) * Keep the two functions in sync.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2371) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2372)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2373) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2374) * The hash list is protected using RCU.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2375) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2376) * Take d_lock when comparing a candidate dentry, to avoid races
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2377) * with d_move().
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2378) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2379) * It is possible that concurrent renames can mess up our list
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2380) * walk here and result in missing our dentry, resulting in the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2381) * false-negative result. d_lookup() protects against concurrent
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2382) * renames using rename_lock seqlock.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2383) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2384) * See Documentation/filesystems/path-lookup.txt for more details.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2385) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2386) rcu_read_lock();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2387)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2388) hlist_bl_for_each_entry_rcu(dentry, node, b, d_hash) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2389)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2390) if (dentry->d_name.hash != hash)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2391) continue;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2392)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2393) spin_lock(&dentry->d_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2394) if (dentry->d_parent != parent)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2395) goto next;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2396) if (d_unhashed(dentry))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2397) goto next;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2398)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2399) if (!d_same_name(dentry, parent, name))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2400) goto next;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2401)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2402) dentry->d_lockref.count++;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2403) found = dentry;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2404) spin_unlock(&dentry->d_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2405) break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2406) next:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2407) spin_unlock(&dentry->d_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2408) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2409) rcu_read_unlock();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2410)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2411) return found;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2412) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2413)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2414) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2415) * d_hash_and_lookup - hash the qstr then search for a dentry
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2416) * @dir: Directory to search in
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2417) * @name: qstr of name we wish to find
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2418) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2419) * On lookup failure NULL is returned; on bad name - ERR_PTR(-error)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2420) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2421) struct dentry *d_hash_and_lookup(struct dentry *dir, struct qstr *name)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2422) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2423) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2424) * Check for a fs-specific hash function. Note that we must
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2425) * calculate the standard hash first, as the d_op->d_hash()
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2426) * routine may choose to leave the hash value unchanged.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2427) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2428) name->hash = full_name_hash(dir, name->name, name->len);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2429) if (dir->d_flags & DCACHE_OP_HASH) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2430) int err = dir->d_op->d_hash(dir, name);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2431) if (unlikely(err < 0))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2432) return ERR_PTR(err);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2433) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2434) return d_lookup(dir, name);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2435) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2436) EXPORT_SYMBOL(d_hash_and_lookup);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2437)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2438) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2439) * When a file is deleted, we have two options:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2440) * - turn this dentry into a negative dentry
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2441) * - unhash this dentry and free it.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2442) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2443) * Usually, we want to just turn this into
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2444) * a negative dentry, but if anybody else is
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2445) * currently using the dentry or the inode
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2446) * we can't do that and we fall back on removing
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2447) * it from the hash queues and waiting for
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2448) * it to be deleted later when it has no users
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2449) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2450)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2451) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2452) * d_delete - delete a dentry
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2453) * @dentry: The dentry to delete
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2454) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2455) * Turn the dentry into a negative dentry if possible, otherwise
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2456) * remove it from the hash queues so it can be deleted later
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2457) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2458)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2459) void d_delete(struct dentry * dentry)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2460) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2461) struct inode *inode = dentry->d_inode;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2462)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2463) spin_lock(&inode->i_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2464) spin_lock(&dentry->d_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2465) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2466) * Are we the only user?
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2467) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2468) if (dentry->d_lockref.count == 1) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2469) dentry->d_flags &= ~DCACHE_CANT_MOUNT;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2470) dentry_unlink_inode(dentry);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2471) } else {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2472) __d_drop(dentry);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2473) spin_unlock(&dentry->d_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2474) spin_unlock(&inode->i_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2475) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2476) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2477) EXPORT_SYMBOL(d_delete);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2478)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2479) static void __d_rehash(struct dentry *entry)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2480) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2481) struct hlist_bl_head *b = d_hash(entry->d_name.hash);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2482)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2483) hlist_bl_lock(b);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2484) hlist_bl_add_head_rcu(&entry->d_hash, b);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2485) hlist_bl_unlock(b);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2486) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2487)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2488) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2489) * d_rehash - add an entry back to the hash
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2490) * @entry: dentry to add to the hash
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2491) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2492) * Adds a dentry to the hash according to its name.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2493) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2494)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2495) void d_rehash(struct dentry * entry)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2496) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2497) spin_lock(&entry->d_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2498) __d_rehash(entry);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2499) spin_unlock(&entry->d_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2500) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2501) EXPORT_SYMBOL(d_rehash);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2502)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2503) static inline unsigned start_dir_add(struct inode *dir)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2504) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2505)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2506) for (;;) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2507) unsigned n = dir->i_dir_seq;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2508) if (!(n & 1) && cmpxchg(&dir->i_dir_seq, n, n + 1) == n)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2509) return n;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2510) cpu_relax();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2511) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2512) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2513)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2514) static inline void end_dir_add(struct inode *dir, unsigned n)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2515) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2516) smp_store_release(&dir->i_dir_seq, n + 2);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2517) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2518)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2519) static void d_wait_lookup(struct dentry *dentry)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2520) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2521) if (d_in_lookup(dentry)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2522) DECLARE_WAITQUEUE(wait, current);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2523) add_wait_queue(dentry->d_wait, &wait);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2524) do {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2525) set_current_state(TASK_UNINTERRUPTIBLE);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2526) spin_unlock(&dentry->d_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2527) schedule();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2528) spin_lock(&dentry->d_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2529) } while (d_in_lookup(dentry));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2530) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2531) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2532)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2533) struct dentry *d_alloc_parallel(struct dentry *parent,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2534) const struct qstr *name,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2535) wait_queue_head_t *wq)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2536) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2537) unsigned int hash = name->hash;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2538) struct hlist_bl_head *b = in_lookup_hash(parent, hash);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2539) struct hlist_bl_node *node;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2540) struct dentry *new = d_alloc(parent, name);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2541) struct dentry *dentry;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2542) unsigned seq, r_seq, d_seq;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2543)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2544) if (unlikely(!new))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2545) return ERR_PTR(-ENOMEM);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2546)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2547) retry:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2548) rcu_read_lock();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2549) seq = smp_load_acquire(&parent->d_inode->i_dir_seq);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2550) r_seq = read_seqbegin(&rename_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2551) dentry = __d_lookup_rcu(parent, name, &d_seq);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2552) if (unlikely(dentry)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2553) if (!lockref_get_not_dead(&dentry->d_lockref)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2554) rcu_read_unlock();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2555) goto retry;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2556) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2557) if (read_seqcount_retry(&dentry->d_seq, d_seq)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2558) rcu_read_unlock();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2559) dput(dentry);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2560) goto retry;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2561) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2562) rcu_read_unlock();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2563) dput(new);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2564) return dentry;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2565) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2566) if (unlikely(read_seqretry(&rename_lock, r_seq))) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2567) rcu_read_unlock();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2568) goto retry;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2569) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2570)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2571) if (unlikely(seq & 1)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2572) rcu_read_unlock();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2573) goto retry;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2574) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2575)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2576) hlist_bl_lock(b);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2577) if (unlikely(READ_ONCE(parent->d_inode->i_dir_seq) != seq)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2578) hlist_bl_unlock(b);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2579) rcu_read_unlock();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2580) goto retry;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2581) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2582) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2583) * No changes for the parent since the beginning of d_lookup().
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2584) * Since all removals from the chain happen with hlist_bl_lock(),
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2585) * any potential in-lookup matches are going to stay here until
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2586) * we unlock the chain. All fields are stable in everything
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2587) * we encounter.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2588) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2589) hlist_bl_for_each_entry(dentry, node, b, d_u.d_in_lookup_hash) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2590) if (dentry->d_name.hash != hash)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2591) continue;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2592) if (dentry->d_parent != parent)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2593) continue;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2594) if (!d_same_name(dentry, parent, name))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2595) continue;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2596) hlist_bl_unlock(b);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2597) /* now we can try to grab a reference */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2598) if (!lockref_get_not_dead(&dentry->d_lockref)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2599) rcu_read_unlock();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2600) goto retry;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2601) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2602)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2603) rcu_read_unlock();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2604) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2605) * somebody is likely to be still doing lookup for it;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2606) * wait for them to finish
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2607) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2608) spin_lock(&dentry->d_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2609) d_wait_lookup(dentry);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2610) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2611) * it's not in-lookup anymore; in principle we should repeat
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2612) * everything from dcache lookup, but it's likely to be what
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2613) * d_lookup() would've found anyway. If it is, just return it;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2614) * otherwise we really have to repeat the whole thing.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2615) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2616) if (unlikely(dentry->d_name.hash != hash))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2617) goto mismatch;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2618) if (unlikely(dentry->d_parent != parent))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2619) goto mismatch;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2620) if (unlikely(d_unhashed(dentry)))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2621) goto mismatch;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2622) if (unlikely(!d_same_name(dentry, parent, name)))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2623) goto mismatch;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2624) /* OK, it *is* a hashed match; return it */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2625) spin_unlock(&dentry->d_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2626) dput(new);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2627) return dentry;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2628) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2629) rcu_read_unlock();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2630) /* we can't take ->d_lock here; it's OK, though. */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2631) new->d_flags |= DCACHE_PAR_LOOKUP;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2632) new->d_wait = wq;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2633) hlist_bl_add_head_rcu(&new->d_u.d_in_lookup_hash, b);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2634) hlist_bl_unlock(b);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2635) return new;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2636) mismatch:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2637) spin_unlock(&dentry->d_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2638) dput(dentry);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2639) goto retry;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2640) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2641) EXPORT_SYMBOL(d_alloc_parallel);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2642)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2643) void __d_lookup_done(struct dentry *dentry)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2644) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2645) struct hlist_bl_head *b = in_lookup_hash(dentry->d_parent,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2646) dentry->d_name.hash);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2647) hlist_bl_lock(b);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2648) dentry->d_flags &= ~DCACHE_PAR_LOOKUP;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2649) __hlist_bl_del(&dentry->d_u.d_in_lookup_hash);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2650) wake_up_all(dentry->d_wait);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2651) dentry->d_wait = NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2652) hlist_bl_unlock(b);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2653) INIT_HLIST_NODE(&dentry->d_u.d_alias);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2654) INIT_LIST_HEAD(&dentry->d_lru);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2655) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2656) EXPORT_SYMBOL(__d_lookup_done);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2657)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2658) /* inode->i_lock held if inode is non-NULL */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2659)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2660) static inline void __d_add(struct dentry *dentry, struct inode *inode)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2661) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2662) struct inode *dir = NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2663) unsigned n;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2664) spin_lock(&dentry->d_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2665) if (unlikely(d_in_lookup(dentry))) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2666) dir = dentry->d_parent->d_inode;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2667) n = start_dir_add(dir);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2668) __d_lookup_done(dentry);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2669) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2670) if (inode) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2671) unsigned add_flags = d_flags_for_inode(inode);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2672) hlist_add_head(&dentry->d_u.d_alias, &inode->i_dentry);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2673) raw_write_seqcount_begin(&dentry->d_seq);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2674) __d_set_inode_and_type(dentry, inode, add_flags);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2675) raw_write_seqcount_end(&dentry->d_seq);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2676) fsnotify_update_flags(dentry);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2677) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2678) __d_rehash(dentry);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2679) if (dir)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2680) end_dir_add(dir, n);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2681) spin_unlock(&dentry->d_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2682) if (inode)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2683) spin_unlock(&inode->i_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2684) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2685)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2686) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2687) * d_add - add dentry to hash queues
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2688) * @entry: dentry to add
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2689) * @inode: The inode to attach to this dentry
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2690) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2691) * This adds the entry to the hash queues and initializes @inode.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2692) * The entry was actually filled in earlier during d_alloc().
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2693) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2694)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2695) void d_add(struct dentry *entry, struct inode *inode)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2696) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2697) if (inode) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2698) security_d_instantiate(entry, inode);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2699) spin_lock(&inode->i_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2700) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2701) __d_add(entry, inode);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2702) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2703) EXPORT_SYMBOL(d_add);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2704)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2705) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2706) * d_exact_alias - find and hash an exact unhashed alias
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2707) * @entry: dentry to add
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2708) * @inode: The inode to go with this dentry
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2709) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2710) * If an unhashed dentry with the same name/parent and desired
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2711) * inode already exists, hash and return it. Otherwise, return
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2712) * NULL.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2713) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2714) * Parent directory should be locked.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2715) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2716) struct dentry *d_exact_alias(struct dentry *entry, struct inode *inode)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2717) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2718) struct dentry *alias;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2719) unsigned int hash = entry->d_name.hash;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2720)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2721) spin_lock(&inode->i_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2722) hlist_for_each_entry(alias, &inode->i_dentry, d_u.d_alias) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2723) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2724) * Don't need alias->d_lock here, because aliases with
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2725) * d_parent == entry->d_parent are not subject to name or
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2726) * parent changes, because the parent inode i_mutex is held.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2727) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2728) if (alias->d_name.hash != hash)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2729) continue;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2730) if (alias->d_parent != entry->d_parent)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2731) continue;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2732) if (!d_same_name(alias, entry->d_parent, &entry->d_name))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2733) continue;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2734) spin_lock(&alias->d_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2735) if (!d_unhashed(alias)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2736) spin_unlock(&alias->d_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2737) alias = NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2738) } else {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2739) __dget_dlock(alias);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2740) __d_rehash(alias);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2741) spin_unlock(&alias->d_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2742) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2743) spin_unlock(&inode->i_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2744) return alias;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2745) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2746) spin_unlock(&inode->i_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2747) return NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2748) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2749) EXPORT_SYMBOL(d_exact_alias);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2750)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2751) static void swap_names(struct dentry *dentry, struct dentry *target)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2752) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2753) if (unlikely(dname_external(target))) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2754) if (unlikely(dname_external(dentry))) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2755) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2756) * Both external: swap the pointers
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2757) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2758) swap(target->d_name.name, dentry->d_name.name);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2759) } else {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2760) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2761) * dentry:internal, target:external. Steal target's
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2762) * storage and make target internal.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2763) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2764) memcpy(target->d_iname, dentry->d_name.name,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2765) dentry->d_name.len + 1);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2766) dentry->d_name.name = target->d_name.name;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2767) target->d_name.name = target->d_iname;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2768) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2769) } else {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2770) if (unlikely(dname_external(dentry))) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2771) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2772) * dentry:external, target:internal. Give dentry's
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2773) * storage to target and make dentry internal
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2774) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2775) memcpy(dentry->d_iname, target->d_name.name,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2776) target->d_name.len + 1);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2777) target->d_name.name = dentry->d_name.name;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2778) dentry->d_name.name = dentry->d_iname;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2779) } else {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2780) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2781) * Both are internal.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2782) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2783) unsigned int i;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2784) BUILD_BUG_ON(!IS_ALIGNED(DNAME_INLINE_LEN, sizeof(long)));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2785) for (i = 0; i < DNAME_INLINE_LEN / sizeof(long); i++) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2786) swap(((long *) &dentry->d_iname)[i],
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2787) ((long *) &target->d_iname)[i]);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2788) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2789) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2790) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2791) swap(dentry->d_name.hash_len, target->d_name.hash_len);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2792) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2793)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2794) static void copy_name(struct dentry *dentry, struct dentry *target)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2795) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2796) struct external_name *old_name = NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2797) if (unlikely(dname_external(dentry)))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2798) old_name = external_name(dentry);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2799) if (unlikely(dname_external(target))) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2800) atomic_inc(&external_name(target)->u.count);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2801) dentry->d_name = target->d_name;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2802) } else {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2803) memcpy(dentry->d_iname, target->d_name.name,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2804) target->d_name.len + 1);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2805) dentry->d_name.name = dentry->d_iname;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2806) dentry->d_name.hash_len = target->d_name.hash_len;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2807) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2808) if (old_name && likely(atomic_dec_and_test(&old_name->u.count)))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2809) kfree_rcu(old_name, u.head);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2810) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2811)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2812) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2813) * __d_move - move a dentry
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2814) * @dentry: entry to move
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2815) * @target: new dentry
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2816) * @exchange: exchange the two dentries
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2817) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2818) * Update the dcache to reflect the move of a file name. Negative
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2819) * dcache entries should not be moved in this way. Caller must hold
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2820) * rename_lock, the i_mutex of the source and target directories,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2821) * and the sb->s_vfs_rename_mutex if they differ. See lock_rename().
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2822) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2823) static void __d_move(struct dentry *dentry, struct dentry *target,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2824) bool exchange)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2825) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2826) struct dentry *old_parent, *p;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2827) struct inode *dir = NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2828) unsigned n;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2829)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2830) WARN_ON(!dentry->d_inode);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2831) if (WARN_ON(dentry == target))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2832) return;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2833)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2834) BUG_ON(d_ancestor(target, dentry));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2835) old_parent = dentry->d_parent;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2836) p = d_ancestor(old_parent, target);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2837) if (IS_ROOT(dentry)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2838) BUG_ON(p);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2839) spin_lock(&target->d_parent->d_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2840) } else if (!p) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2841) /* target is not a descendent of dentry->d_parent */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2842) spin_lock(&target->d_parent->d_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2843) spin_lock_nested(&old_parent->d_lock, DENTRY_D_LOCK_NESTED);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2844) } else {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2845) BUG_ON(p == dentry);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2846) spin_lock(&old_parent->d_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2847) if (p != target)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2848) spin_lock_nested(&target->d_parent->d_lock,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2849) DENTRY_D_LOCK_NESTED);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2850) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2851) spin_lock_nested(&dentry->d_lock, 2);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2852) spin_lock_nested(&target->d_lock, 3);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2853)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2854) if (unlikely(d_in_lookup(target))) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2855) dir = target->d_parent->d_inode;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2856) n = start_dir_add(dir);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2857) __d_lookup_done(target);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2858) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2859)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2860) write_seqcount_begin(&dentry->d_seq);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2861) write_seqcount_begin_nested(&target->d_seq, DENTRY_D_LOCK_NESTED);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2862)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2863) /* unhash both */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2864) if (!d_unhashed(dentry))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2865) ___d_drop(dentry);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2866) if (!d_unhashed(target))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2867) ___d_drop(target);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2868)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2869) /* ... and switch them in the tree */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2870) dentry->d_parent = target->d_parent;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2871) if (!exchange) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2872) copy_name(dentry, target);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2873) target->d_hash.pprev = NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2874) dentry->d_parent->d_lockref.count++;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2875) if (dentry != old_parent) /* wasn't IS_ROOT */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2876) WARN_ON(!--old_parent->d_lockref.count);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2877) } else {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2878) target->d_parent = old_parent;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2879) swap_names(dentry, target);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2880) list_move(&target->d_child, &target->d_parent->d_subdirs);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2881) __d_rehash(target);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2882) fsnotify_update_flags(target);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2883) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2884) list_move(&dentry->d_child, &dentry->d_parent->d_subdirs);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2885) __d_rehash(dentry);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2886) fsnotify_update_flags(dentry);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2887) fscrypt_handle_d_move(dentry);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2888)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2889) write_seqcount_end(&target->d_seq);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2890) write_seqcount_end(&dentry->d_seq);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2891)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2892) if (dir)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2893) end_dir_add(dir, n);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2894)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2895) if (dentry->d_parent != old_parent)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2896) spin_unlock(&dentry->d_parent->d_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2897) if (dentry != old_parent)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2898) spin_unlock(&old_parent->d_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2899) spin_unlock(&target->d_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2900) spin_unlock(&dentry->d_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2901) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2902)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2903) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2904) * d_move - move a dentry
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2905) * @dentry: entry to move
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2906) * @target: new dentry
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2907) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2908) * Update the dcache to reflect the move of a file name. Negative
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2909) * dcache entries should not be moved in this way. See the locking
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2910) * requirements for __d_move.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2911) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2912) void d_move(struct dentry *dentry, struct dentry *target)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2913) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2914) write_seqlock(&rename_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2915) __d_move(dentry, target, false);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2916) write_sequnlock(&rename_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2917) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2918) EXPORT_SYMBOL(d_move);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2919)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2920) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2921) * d_exchange - exchange two dentries
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2922) * @dentry1: first dentry
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2923) * @dentry2: second dentry
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2924) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2925) void d_exchange(struct dentry *dentry1, struct dentry *dentry2)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2926) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2927) write_seqlock(&rename_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2928)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2929) WARN_ON(!dentry1->d_inode);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2930) WARN_ON(!dentry2->d_inode);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2931) WARN_ON(IS_ROOT(dentry1));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2932) WARN_ON(IS_ROOT(dentry2));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2933)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2934) __d_move(dentry1, dentry2, true);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2935)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2936) write_sequnlock(&rename_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2937) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2938)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2939) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2940) * d_ancestor - search for an ancestor
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2941) * @p1: ancestor dentry
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2942) * @p2: child dentry
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2943) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2944) * Returns the ancestor dentry of p2 which is a child of p1, if p1 is
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2945) * an ancestor of p2, else NULL.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2946) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2947) struct dentry *d_ancestor(struct dentry *p1, struct dentry *p2)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2948) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2949) struct dentry *p;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2950)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2951) for (p = p2; !IS_ROOT(p); p = p->d_parent) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2952) if (p->d_parent == p1)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2953) return p;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2954) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2955) return NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2956) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2957)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2958) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2959) * This helper attempts to cope with remotely renamed directories
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2960) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2961) * It assumes that the caller is already holding
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2962) * dentry->d_parent->d_inode->i_mutex, and rename_lock
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2963) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2964) * Note: If ever the locking in lock_rename() changes, then please
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2965) * remember to update this too...
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2966) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2967) static int __d_unalias(struct inode *inode,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2968) struct dentry *dentry, struct dentry *alias)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2969) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2970) struct mutex *m1 = NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2971) struct rw_semaphore *m2 = NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2972) int ret = -ESTALE;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2973)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2974) /* If alias and dentry share a parent, then no extra locks required */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2975) if (alias->d_parent == dentry->d_parent)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2976) goto out_unalias;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2977)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2978) /* See lock_rename() */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2979) if (!mutex_trylock(&dentry->d_sb->s_vfs_rename_mutex))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2980) goto out_err;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2981) m1 = &dentry->d_sb->s_vfs_rename_mutex;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2982) if (!inode_trylock_shared(alias->d_parent->d_inode))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2983) goto out_err;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2984) m2 = &alias->d_parent->d_inode->i_rwsem;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2985) out_unalias:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2986) __d_move(alias, dentry, false);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2987) ret = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2988) out_err:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2989) if (m2)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2990) up_read(m2);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2991) if (m1)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2992) mutex_unlock(m1);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2993) return ret;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2994) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2995)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2996) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2997) * d_splice_alias - splice a disconnected dentry into the tree if one exists
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2998) * @inode: the inode which may have a disconnected dentry
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2999) * @dentry: a negative dentry which we want to point to the inode.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3000) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3001) * If inode is a directory and has an IS_ROOT alias, then d_move that in
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3002) * place of the given dentry and return it, else simply d_add the inode
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3003) * to the dentry and return NULL.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3004) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3005) * If a non-IS_ROOT directory is found, the filesystem is corrupt, and
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3006) * we should error out: directories can't have multiple aliases.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3007) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3008) * This is needed in the lookup routine of any filesystem that is exportable
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3009) * (via knfsd) so that we can build dcache paths to directories effectively.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3010) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3011) * If a dentry was found and moved, then it is returned. Otherwise NULL
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3012) * is returned. This matches the expected return value of ->lookup.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3013) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3014) * Cluster filesystems may call this function with a negative, hashed dentry.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3015) * In that case, we know that the inode will be a regular file, and also this
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3016) * will only occur during atomic_open. So we need to check for the dentry
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3017) * being already hashed only in the final case.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3018) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3019) struct dentry *d_splice_alias(struct inode *inode, struct dentry *dentry)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3020) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3021) if (IS_ERR(inode))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3022) return ERR_CAST(inode);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3023)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3024) BUG_ON(!d_unhashed(dentry));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3025)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3026) if (!inode)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3027) goto out;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3028)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3029) security_d_instantiate(dentry, inode);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3030) spin_lock(&inode->i_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3031) if (S_ISDIR(inode->i_mode)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3032) struct dentry *new = __d_find_any_alias(inode);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3033) if (unlikely(new)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3034) /* The reference to new ensures it remains an alias */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3035) spin_unlock(&inode->i_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3036) write_seqlock(&rename_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3037) if (unlikely(d_ancestor(new, dentry))) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3038) write_sequnlock(&rename_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3039) dput(new);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3040) new = ERR_PTR(-ELOOP);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3041) pr_warn_ratelimited(
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3042) "VFS: Lookup of '%s' in %s %s"
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3043) " would have caused loop\n",
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3044) dentry->d_name.name,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3045) inode->i_sb->s_type->name,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3046) inode->i_sb->s_id);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3047) } else if (!IS_ROOT(new)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3048) struct dentry *old_parent = dget(new->d_parent);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3049) int err = __d_unalias(inode, dentry, new);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3050) write_sequnlock(&rename_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3051) if (err) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3052) dput(new);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3053) new = ERR_PTR(err);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3054) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3055) dput(old_parent);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3056) } else {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3057) __d_move(new, dentry, false);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3058) write_sequnlock(&rename_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3059) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3060) iput(inode);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3061) return new;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3062) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3063) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3064) out:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3065) __d_add(dentry, inode);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3066) return NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3067) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3068) EXPORT_SYMBOL_NS(d_splice_alias, ANDROID_GKI_VFS_EXPORT_ONLY);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3069)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3070) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3071) * Test whether new_dentry is a subdirectory of old_dentry.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3072) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3073) * Trivially implemented using the dcache structure
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3074) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3075)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3076) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3077) * is_subdir - is new dentry a subdirectory of old_dentry
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3078) * @new_dentry: new dentry
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3079) * @old_dentry: old dentry
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3080) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3081) * Returns true if new_dentry is a subdirectory of the parent (at any depth).
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3082) * Returns false otherwise.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3083) * Caller must ensure that "new_dentry" is pinned before calling is_subdir()
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3084) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3085)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3086) bool is_subdir(struct dentry *new_dentry, struct dentry *old_dentry)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3087) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3088) bool result;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3089) unsigned seq;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3090)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3091) if (new_dentry == old_dentry)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3092) return true;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3093)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3094) do {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3095) /* for restarting inner loop in case of seq retry */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3096) seq = read_seqbegin(&rename_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3097) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3098) * Need rcu_readlock to protect against the d_parent trashing
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3099) * due to d_move
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3100) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3101) rcu_read_lock();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3102) if (d_ancestor(old_dentry, new_dentry))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3103) result = true;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3104) else
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3105) result = false;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3106) rcu_read_unlock();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3107) } while (read_seqretry(&rename_lock, seq));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3108)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3109) return result;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3110) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3111) EXPORT_SYMBOL(is_subdir);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3112)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3113) static enum d_walk_ret d_genocide_kill(void *data, struct dentry *dentry)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3114) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3115) struct dentry *root = data;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3116) if (dentry != root) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3117) if (d_unhashed(dentry) || !dentry->d_inode)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3118) return D_WALK_SKIP;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3119)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3120) if (!(dentry->d_flags & DCACHE_GENOCIDE)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3121) dentry->d_flags |= DCACHE_GENOCIDE;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3122) dentry->d_lockref.count--;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3123) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3124) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3125) return D_WALK_CONTINUE;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3126) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3127)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3128) void d_genocide(struct dentry *parent)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3129) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3130) d_walk(parent, parent, d_genocide_kill);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3131) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3132)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3133) EXPORT_SYMBOL(d_genocide);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3134)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3135) void d_tmpfile(struct dentry *dentry, struct inode *inode)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3136) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3137) inode_dec_link_count(inode);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3138) BUG_ON(dentry->d_name.name != dentry->d_iname ||
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3139) !hlist_unhashed(&dentry->d_u.d_alias) ||
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3140) !d_unlinked(dentry));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3141) spin_lock(&dentry->d_parent->d_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3142) spin_lock_nested(&dentry->d_lock, DENTRY_D_LOCK_NESTED);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3143) dentry->d_name.len = sprintf(dentry->d_iname, "#%llu",
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3144) (unsigned long long)inode->i_ino);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3145) spin_unlock(&dentry->d_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3146) spin_unlock(&dentry->d_parent->d_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3147) d_instantiate(dentry, inode);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3148) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3149) EXPORT_SYMBOL(d_tmpfile);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3150)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3151) static __initdata unsigned long dhash_entries;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3152) static int __init set_dhash_entries(char *str)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3153) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3154) if (!str)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3155) return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3156) dhash_entries = simple_strtoul(str, &str, 0);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3157) return 1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3158) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3159) __setup("dhash_entries=", set_dhash_entries);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3160)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3161) static void __init dcache_init_early(void)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3162) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3163) /* If hashes are distributed across NUMA nodes, defer
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3164) * hash allocation until vmalloc space is available.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3165) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3166) if (hashdist)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3167) return;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3168)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3169) dentry_hashtable =
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3170) alloc_large_system_hash("Dentry cache",
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3171) sizeof(struct hlist_bl_head),
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3172) dhash_entries,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3173) 13,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3174) HASH_EARLY | HASH_ZERO,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3175) &d_hash_shift,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3176) NULL,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3177) 0,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3178) 0);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3179) d_hash_shift = 32 - d_hash_shift;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3180) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3181)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3182) static void __init dcache_init(void)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3183) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3184) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3185) * A constructor could be added for stable state like the lists,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3186) * but it is probably not worth it because of the cache nature
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3187) * of the dcache.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3188) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3189) dentry_cache = KMEM_CACHE_USERCOPY(dentry,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3190) SLAB_RECLAIM_ACCOUNT|SLAB_PANIC|SLAB_MEM_SPREAD|SLAB_ACCOUNT,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3191) d_iname);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3192)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3193) /* Hash may have been set up in dcache_init_early */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3194) if (!hashdist)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3195) return;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3196)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3197) dentry_hashtable =
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3198) alloc_large_system_hash("Dentry cache",
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3199) sizeof(struct hlist_bl_head),
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3200) dhash_entries,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3201) 13,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3202) HASH_ZERO,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3203) &d_hash_shift,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3204) NULL,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3205) 0,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3206) 0);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3207) d_hash_shift = 32 - d_hash_shift;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3208) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3209)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3210) /* SLAB cache for __getname() consumers */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3211) struct kmem_cache *names_cachep __read_mostly;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3212) EXPORT_SYMBOL(names_cachep);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3213)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3214) void __init vfs_caches_init_early(void)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3215) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3216) int i;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3217)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3218) for (i = 0; i < ARRAY_SIZE(in_lookup_hashtable); i++)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3219) INIT_HLIST_BL_HEAD(&in_lookup_hashtable[i]);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3220)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3221) dcache_init_early();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3222) inode_init_early();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3223) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3224)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3225) void __init vfs_caches_init(void)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3226) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3227) names_cachep = kmem_cache_create_usercopy("names_cache", PATH_MAX, 0,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3228) SLAB_HWCACHE_ALIGN|SLAB_PANIC, 0, PATH_MAX, NULL);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3229)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3230) dcache_init();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3231) inode_init();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3232) files_init();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3233) files_maxfiles_init();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3234) mnt_init();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3235) bdev_cache_init();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3236) chrdev_init();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3237) }
Orange Pi5 kernel
Deprecated Linux kernel 5.10.110 for OrangePi 5/5B/5+ boards
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