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- #include <linux/syscalls.h>
- #include <linux/string.h>
- #include <linux/mm.h>
- #include <linux/fs.h>
- #include <linux/fsnotify.h>
- #include <linux/slab.h>
- #include <linux/init.h>
- #include <linux/hash.h>
- #include <linux/cache.h>
- #include <linux/export.h>
- #include <linux/mount.h>
- #include <linux/file.h>
- #include <asm/uaccess.h>
- #include <linux/security.h>
- #include <linux/seqlock.h>
- #include <linux/swap.h>
- #include <linux/bootmem.h>
- #include <linux/fs_struct.h>
- #include <linux/hardirq.h>
- #include <linux/bit_spinlock.h>
- #include <linux/rculist_bl.h>
- #include <linux/prefetch.h>
- #include <linux/ratelimit.h>
- #include <linux/list_lru.h>
- #include <linux/kasan.h>
- #include "internal.h"
- #include "mount.h"
- int sysctl_vfs_cache_pressure __read_mostly = 100;
- EXPORT_SYMBOL_GPL(sysctl_vfs_cache_pressure);
- __cacheline_aligned_in_smp DEFINE_SEQLOCK(rename_lock);
- EXPORT_SYMBOL(rename_lock);
- static struct kmem_cache *dentry_cache __read_mostly;
- static unsigned int d_hash_mask __read_mostly;
- static unsigned int d_hash_shift __read_mostly;
- static struct hlist_bl_head *dentry_hashtable __read_mostly;
- static inline struct hlist_bl_head *d_hash(unsigned int hash)
- {
- return dentry_hashtable + (hash >> (32 - d_hash_shift));
- }
- #define IN_LOOKUP_SHIFT 10
- static struct hlist_bl_head in_lookup_hashtable[1 << IN_LOOKUP_SHIFT];
- static inline struct hlist_bl_head *in_lookup_hash(const struct dentry *parent,
- unsigned int hash)
- {
- hash += (unsigned long) parent / L1_CACHE_BYTES;
- return in_lookup_hashtable + hash_32(hash, IN_LOOKUP_SHIFT);
- }
- struct dentry_stat_t dentry_stat = {
- .age_limit = 45,
- };
- static DEFINE_PER_CPU(long, nr_dentry);
- static DEFINE_PER_CPU(long, nr_dentry_unused);
- #if defined(CONFIG_SYSCTL) && defined(CONFIG_PROC_FS)
- static long get_nr_dentry(void)
- {
- int i;
- long sum = 0;
- for_each_possible_cpu(i)
- sum += per_cpu(nr_dentry, i);
- return sum < 0 ? 0 : sum;
- }
- static long get_nr_dentry_unused(void)
- {
- int i;
- long sum = 0;
- for_each_possible_cpu(i)
- sum += per_cpu(nr_dentry_unused, i);
- return sum < 0 ? 0 : sum;
- }
- int proc_nr_dentry(struct ctl_table *table, int write, void __user *buffer,
- size_t *lenp, loff_t *ppos)
- {
- dentry_stat.nr_dentry = get_nr_dentry();
- dentry_stat.nr_unused = get_nr_dentry_unused();
- return proc_doulongvec_minmax(table, write, buffer, lenp, ppos);
- }
- #endif
- #ifdef CONFIG_DCACHE_WORD_ACCESS
- #include <asm/word-at-a-time.h>
- static inline int dentry_string_cmp(const unsigned char *cs, const unsigned char *ct, unsigned tcount)
- {
- unsigned long a,b,mask;
- for (;;) {
- a = *(unsigned long *)cs;
- b = load_unaligned_zeropad(ct);
- if (tcount < sizeof(unsigned long))
- break;
- if (unlikely(a != b))
- return 1;
- cs += sizeof(unsigned long);
- ct += sizeof(unsigned long);
- tcount -= sizeof(unsigned long);
- if (!tcount)
- return 0;
- }
- mask = bytemask_from_count(tcount);
- return unlikely(!!((a ^ b) & mask));
- }
- #else
- static inline int dentry_string_cmp(const unsigned char *cs, const unsigned char *ct, unsigned tcount)
- {
- do {
- if (*cs != *ct)
- return 1;
- cs++;
- ct++;
- tcount--;
- } while (tcount);
- return 0;
- }
- #endif
- static inline int dentry_cmp(const struct dentry *dentry, const unsigned char *ct, unsigned tcount)
- {
-
- const unsigned char *cs = lockless_dereference(dentry->d_name.name);
- return dentry_string_cmp(cs, ct, tcount);
- }
- struct external_name {
- union {
- atomic_t count;
- struct rcu_head head;
- } u;
- unsigned char name[];
- };
- static inline struct external_name *external_name(struct dentry *dentry)
- {
- return container_of(dentry->d_name.name, struct external_name, name[0]);
- }
- static void __d_free(struct rcu_head *head)
- {
- struct dentry *dentry = container_of(head, struct dentry, d_u.d_rcu);
- kmem_cache_free(dentry_cache, dentry);
- }
- static void __d_free_external(struct rcu_head *head)
- {
- struct dentry *dentry = container_of(head, struct dentry, d_u.d_rcu);
- kfree(external_name(dentry));
- kmem_cache_free(dentry_cache, dentry);
- }
- static inline int dname_external(const struct dentry *dentry)
- {
- return dentry->d_name.name != dentry->d_iname;
- }
- void take_dentry_name_snapshot(struct name_snapshot *name, struct dentry *dentry)
- {
- spin_lock(&dentry->d_lock);
- if (unlikely(dname_external(dentry))) {
- struct external_name *p = external_name(dentry);
- atomic_inc(&p->u.count);
- spin_unlock(&dentry->d_lock);
- name->name = p->name;
- } else {
- memcpy(name->inline_name, dentry->d_iname, DNAME_INLINE_LEN);
- spin_unlock(&dentry->d_lock);
- name->name = name->inline_name;
- }
- }
- EXPORT_SYMBOL(take_dentry_name_snapshot);
- void release_dentry_name_snapshot(struct name_snapshot *name)
- {
- if (unlikely(name->name != name->inline_name)) {
- struct external_name *p;
- p = container_of(name->name, struct external_name, name[0]);
- if (unlikely(atomic_dec_and_test(&p->u.count)))
- kfree_rcu(p, u.head);
- }
- }
- EXPORT_SYMBOL(release_dentry_name_snapshot);
- static inline void __d_set_inode_and_type(struct dentry *dentry,
- struct inode *inode,
- unsigned type_flags)
- {
- unsigned flags;
- dentry->d_inode = inode;
- flags = READ_ONCE(dentry->d_flags);
- flags &= ~(DCACHE_ENTRY_TYPE | DCACHE_FALLTHRU);
- flags |= type_flags;
- WRITE_ONCE(dentry->d_flags, flags);
- }
- static inline void __d_clear_type_and_inode(struct dentry *dentry)
- {
- unsigned flags = READ_ONCE(dentry->d_flags);
- flags &= ~(DCACHE_ENTRY_TYPE | DCACHE_FALLTHRU);
- WRITE_ONCE(dentry->d_flags, flags);
- dentry->d_inode = NULL;
- }
- static void dentry_free(struct dentry *dentry)
- {
- WARN_ON(!hlist_unhashed(&dentry->d_u.d_alias));
- if (unlikely(dname_external(dentry))) {
- struct external_name *p = external_name(dentry);
- if (likely(atomic_dec_and_test(&p->u.count))) {
- call_rcu(&dentry->d_u.d_rcu, __d_free_external);
- return;
- }
- }
-
- if (!(dentry->d_flags & DCACHE_RCUACCESS))
- __d_free(&dentry->d_u.d_rcu);
- else
- call_rcu(&dentry->d_u.d_rcu, __d_free);
- }
- static void dentry_unlink_inode(struct dentry * dentry)
- __releases(dentry->d_lock)
- __releases(dentry->d_inode->i_lock)
- {
- struct inode *inode = dentry->d_inode;
- bool hashed = !d_unhashed(dentry);
- if (hashed)
- raw_write_seqcount_begin(&dentry->d_seq);
- __d_clear_type_and_inode(dentry);
- hlist_del_init(&dentry->d_u.d_alias);
- if (hashed)
- raw_write_seqcount_end(&dentry->d_seq);
- spin_unlock(&dentry->d_lock);
- spin_unlock(&inode->i_lock);
- if (!inode->i_nlink)
- fsnotify_inoderemove(inode);
- if (dentry->d_op && dentry->d_op->d_iput)
- dentry->d_op->d_iput(dentry, inode);
- else
- iput(inode);
- }
- #define D_FLAG_VERIFY(dentry,x) WARN_ON_ONCE(((dentry)->d_flags & (DCACHE_LRU_LIST | DCACHE_SHRINK_LIST)) != (x))
- static void d_lru_add(struct dentry *dentry)
- {
- D_FLAG_VERIFY(dentry, 0);
- dentry->d_flags |= DCACHE_LRU_LIST;
- this_cpu_inc(nr_dentry_unused);
- WARN_ON_ONCE(!list_lru_add(&dentry->d_sb->s_dentry_lru, &dentry->d_lru));
- }
- static void d_lru_del(struct dentry *dentry)
- {
- D_FLAG_VERIFY(dentry, DCACHE_LRU_LIST);
- dentry->d_flags &= ~DCACHE_LRU_LIST;
- this_cpu_dec(nr_dentry_unused);
- WARN_ON_ONCE(!list_lru_del(&dentry->d_sb->s_dentry_lru, &dentry->d_lru));
- }
- static void d_shrink_del(struct dentry *dentry)
- {
- D_FLAG_VERIFY(dentry, DCACHE_SHRINK_LIST | DCACHE_LRU_LIST);
- list_del_init(&dentry->d_lru);
- dentry->d_flags &= ~(DCACHE_SHRINK_LIST | DCACHE_LRU_LIST);
- this_cpu_dec(nr_dentry_unused);
- }
- static void d_shrink_add(struct dentry *dentry, struct list_head *list)
- {
- D_FLAG_VERIFY(dentry, 0);
- list_add(&dentry->d_lru, list);
- dentry->d_flags |= DCACHE_SHRINK_LIST | DCACHE_LRU_LIST;
- this_cpu_inc(nr_dentry_unused);
- }
- static void d_lru_isolate(struct list_lru_one *lru, struct dentry *dentry)
- {
- D_FLAG_VERIFY(dentry, DCACHE_LRU_LIST);
- dentry->d_flags &= ~DCACHE_LRU_LIST;
- this_cpu_dec(nr_dentry_unused);
- list_lru_isolate(lru, &dentry->d_lru);
- }
- static void d_lru_shrink_move(struct list_lru_one *lru, struct dentry *dentry,
- struct list_head *list)
- {
- D_FLAG_VERIFY(dentry, DCACHE_LRU_LIST);
- dentry->d_flags |= DCACHE_SHRINK_LIST;
- list_lru_isolate_move(lru, &dentry->d_lru, list);
- }
- static void dentry_lru_add(struct dentry *dentry)
- {
- if (unlikely(!(dentry->d_flags & DCACHE_LRU_LIST)))
- d_lru_add(dentry);
- }
- static void ___d_drop(struct dentry *dentry)
- {
- if (!d_unhashed(dentry)) {
- struct hlist_bl_head *b;
-
- if (unlikely(IS_ROOT(dentry)))
- b = &dentry->d_sb->s_anon;
- else
- b = d_hash(dentry->d_name.hash);
- hlist_bl_lock(b);
- __hlist_bl_del(&dentry->d_hash);
- hlist_bl_unlock(b);
-
- write_seqcount_invalidate(&dentry->d_seq);
- }
- }
- void __d_drop(struct dentry *dentry)
- {
- ___d_drop(dentry);
- dentry->d_hash.pprev = NULL;
- }
- EXPORT_SYMBOL(__d_drop);
- void d_drop(struct dentry *dentry)
- {
- spin_lock(&dentry->d_lock);
- __d_drop(dentry);
- spin_unlock(&dentry->d_lock);
- }
- EXPORT_SYMBOL(d_drop);
- static inline void dentry_unlist(struct dentry *dentry, struct dentry *parent)
- {
- struct dentry *next;
-
- dentry->d_flags |= DCACHE_DENTRY_KILLED;
- if (unlikely(list_empty(&dentry->d_child)))
- return;
- __list_del_entry(&dentry->d_child);
-
- while (dentry->d_child.next != &parent->d_subdirs) {
- next = list_entry(dentry->d_child.next, struct dentry, d_child);
- if (likely(!(next->d_flags & DCACHE_DENTRY_CURSOR)))
- break;
- dentry->d_child.next = next->d_child.next;
- }
- }
- static void __dentry_kill(struct dentry *dentry)
- {
- struct dentry *parent = NULL;
- bool can_free = true;
- if (!IS_ROOT(dentry))
- parent = dentry->d_parent;
-
- lockref_mark_dead(&dentry->d_lockref);
-
- if (dentry->d_flags & DCACHE_OP_PRUNE)
- dentry->d_op->d_prune(dentry);
- if (dentry->d_flags & DCACHE_LRU_LIST) {
- if (!(dentry->d_flags & DCACHE_SHRINK_LIST))
- d_lru_del(dentry);
- }
-
- __d_drop(dentry);
- dentry_unlist(dentry, parent);
- if (parent)
- spin_unlock(&parent->d_lock);
- if (dentry->d_inode)
- dentry_unlink_inode(dentry);
- else
- spin_unlock(&dentry->d_lock);
- this_cpu_dec(nr_dentry);
- if (dentry->d_op && dentry->d_op->d_release)
- dentry->d_op->d_release(dentry);
- spin_lock(&dentry->d_lock);
- if (dentry->d_flags & DCACHE_SHRINK_LIST) {
- dentry->d_flags |= DCACHE_MAY_FREE;
- can_free = false;
- }
- spin_unlock(&dentry->d_lock);
- if (likely(can_free))
- dentry_free(dentry);
- }
- static struct dentry *dentry_kill(struct dentry *dentry)
- __releases(dentry->d_lock)
- {
- struct inode *inode = dentry->d_inode;
- struct dentry *parent = NULL;
- if (inode && unlikely(!spin_trylock(&inode->i_lock)))
- goto failed;
- if (!IS_ROOT(dentry)) {
- parent = dentry->d_parent;
- if (unlikely(!spin_trylock(&parent->d_lock))) {
- if (inode)
- spin_unlock(&inode->i_lock);
- goto failed;
- }
- }
- __dentry_kill(dentry);
- return parent;
- failed:
- spin_unlock(&dentry->d_lock);
- return dentry;
- }
- static inline struct dentry *lock_parent(struct dentry *dentry)
- {
- struct dentry *parent = dentry->d_parent;
- if (IS_ROOT(dentry))
- return NULL;
- if (unlikely(dentry->d_lockref.count < 0))
- return NULL;
- if (likely(spin_trylock(&parent->d_lock)))
- return parent;
- rcu_read_lock();
- spin_unlock(&dentry->d_lock);
- again:
- parent = ACCESS_ONCE(dentry->d_parent);
- spin_lock(&parent->d_lock);
-
- if (unlikely(parent != dentry->d_parent)) {
- spin_unlock(&parent->d_lock);
- goto again;
- }
- if (parent != dentry) {
- spin_lock_nested(&dentry->d_lock, DENTRY_D_LOCK_NESTED);
- if (unlikely(dentry->d_lockref.count < 0)) {
- spin_unlock(&parent->d_lock);
- parent = NULL;
- }
- } else {
- parent = NULL;
- }
- rcu_read_unlock();
- return parent;
- }
- static inline bool fast_dput(struct dentry *dentry)
- {
- int ret;
- unsigned int d_flags;
-
- if (unlikely(dentry->d_flags & DCACHE_OP_DELETE))
- return lockref_put_or_lock(&dentry->d_lockref);
-
- ret = lockref_put_return(&dentry->d_lockref);
-
- if (unlikely(ret < 0)) {
- spin_lock(&dentry->d_lock);
- if (dentry->d_lockref.count > 1) {
- dentry->d_lockref.count--;
- spin_unlock(&dentry->d_lock);
- return 1;
- }
- return 0;
- }
-
- if (ret)
- return 1;
-
- smp_rmb();
- d_flags = ACCESS_ONCE(dentry->d_flags);
- d_flags &= DCACHE_REFERENCED | DCACHE_LRU_LIST | DCACHE_DISCONNECTED;
-
- if (d_flags == (DCACHE_REFERENCED | DCACHE_LRU_LIST) && !d_unhashed(dentry))
- return 1;
-
- spin_lock(&dentry->d_lock);
-
- if (dentry->d_lockref.count) {
- spin_unlock(&dentry->d_lock);
- return 1;
- }
-
- dentry->d_lockref.count = 1;
- return 0;
- }
- void dput(struct dentry *dentry)
- {
- if (unlikely(!dentry))
- return;
- repeat:
- might_sleep();
- rcu_read_lock();
- if (likely(fast_dput(dentry))) {
- rcu_read_unlock();
- return;
- }
-
- rcu_read_unlock();
- WARN_ON(d_in_lookup(dentry));
-
- if (unlikely(d_unhashed(dentry)))
- goto kill_it;
- if (unlikely(dentry->d_flags & DCACHE_DISCONNECTED))
- goto kill_it;
- if (unlikely(dentry->d_flags & DCACHE_OP_DELETE)) {
- if (dentry->d_op->d_delete(dentry))
- goto kill_it;
- }
- if (!(dentry->d_flags & DCACHE_REFERENCED))
- dentry->d_flags |= DCACHE_REFERENCED;
- dentry_lru_add(dentry);
- dentry->d_lockref.count--;
- spin_unlock(&dentry->d_lock);
- return;
- kill_it:
- dentry = dentry_kill(dentry);
- if (dentry) {
- cond_resched();
- goto repeat;
- }
- }
- EXPORT_SYMBOL(dput);
- static inline void __dget_dlock(struct dentry *dentry)
- {
- dentry->d_lockref.count++;
- }
- static inline void __dget(struct dentry *dentry)
- {
- lockref_get(&dentry->d_lockref);
- }
- struct dentry *dget_parent(struct dentry *dentry)
- {
- int gotref;
- struct dentry *ret;
-
- rcu_read_lock();
- ret = ACCESS_ONCE(dentry->d_parent);
- gotref = lockref_get_not_zero(&ret->d_lockref);
- rcu_read_unlock();
- if (likely(gotref)) {
- if (likely(ret == ACCESS_ONCE(dentry->d_parent)))
- return ret;
- dput(ret);
- }
- repeat:
-
- rcu_read_lock();
- ret = dentry->d_parent;
- spin_lock(&ret->d_lock);
- if (unlikely(ret != dentry->d_parent)) {
- spin_unlock(&ret->d_lock);
- rcu_read_unlock();
- goto repeat;
- }
- rcu_read_unlock();
- BUG_ON(!ret->d_lockref.count);
- ret->d_lockref.count++;
- spin_unlock(&ret->d_lock);
- return ret;
- }
- EXPORT_SYMBOL(dget_parent);
- static struct dentry *__d_find_alias(struct inode *inode)
- {
- struct dentry *alias, *discon_alias;
- again:
- discon_alias = NULL;
- hlist_for_each_entry(alias, &inode->i_dentry, d_u.d_alias) {
- spin_lock(&alias->d_lock);
- if (S_ISDIR(inode->i_mode) || !d_unhashed(alias)) {
- if (IS_ROOT(alias) &&
- (alias->d_flags & DCACHE_DISCONNECTED)) {
- discon_alias = alias;
- } else {
- __dget_dlock(alias);
- spin_unlock(&alias->d_lock);
- return alias;
- }
- }
- spin_unlock(&alias->d_lock);
- }
- if (discon_alias) {
- alias = discon_alias;
- spin_lock(&alias->d_lock);
- if (S_ISDIR(inode->i_mode) || !d_unhashed(alias)) {
- __dget_dlock(alias);
- spin_unlock(&alias->d_lock);
- return alias;
- }
- spin_unlock(&alias->d_lock);
- goto again;
- }
- return NULL;
- }
- struct dentry *d_find_alias(struct inode *inode)
- {
- struct dentry *de = NULL;
- if (!hlist_empty(&inode->i_dentry)) {
- spin_lock(&inode->i_lock);
- de = __d_find_alias(inode);
- spin_unlock(&inode->i_lock);
- }
- return de;
- }
- EXPORT_SYMBOL(d_find_alias);
- void d_prune_aliases(struct inode *inode)
- {
- struct dentry *dentry;
- restart:
- spin_lock(&inode->i_lock);
- hlist_for_each_entry(dentry, &inode->i_dentry, d_u.d_alias) {
- spin_lock(&dentry->d_lock);
- if (!dentry->d_lockref.count) {
- struct dentry *parent = lock_parent(dentry);
- if (likely(!dentry->d_lockref.count)) {
- __dentry_kill(dentry);
- dput(parent);
- goto restart;
- }
- if (parent)
- spin_unlock(&parent->d_lock);
- }
- spin_unlock(&dentry->d_lock);
- }
- spin_unlock(&inode->i_lock);
- }
- EXPORT_SYMBOL(d_prune_aliases);
- static void shrink_dentry_list(struct list_head *list)
- {
- struct dentry *dentry, *parent;
- while (!list_empty(list)) {
- struct inode *inode;
- dentry = list_entry(list->prev, struct dentry, d_lru);
- spin_lock(&dentry->d_lock);
- parent = lock_parent(dentry);
-
- d_shrink_del(dentry);
-
- if (dentry->d_lockref.count > 0) {
- spin_unlock(&dentry->d_lock);
- if (parent)
- spin_unlock(&parent->d_lock);
- continue;
- }
- if (unlikely(dentry->d_flags & DCACHE_DENTRY_KILLED)) {
- bool can_free = dentry->d_flags & DCACHE_MAY_FREE;
- spin_unlock(&dentry->d_lock);
- if (parent)
- spin_unlock(&parent->d_lock);
- if (can_free)
- dentry_free(dentry);
- continue;
- }
- inode = dentry->d_inode;
- if (inode && unlikely(!spin_trylock(&inode->i_lock))) {
- d_shrink_add(dentry, list);
- spin_unlock(&dentry->d_lock);
- if (parent)
- spin_unlock(&parent->d_lock);
- continue;
- }
- __dentry_kill(dentry);
-
- dentry = parent;
- while (dentry && !lockref_put_or_lock(&dentry->d_lockref)) {
- parent = lock_parent(dentry);
- if (dentry->d_lockref.count != 1) {
- dentry->d_lockref.count--;
- spin_unlock(&dentry->d_lock);
- if (parent)
- spin_unlock(&parent->d_lock);
- break;
- }
- inode = dentry->d_inode;
- if (unlikely(!spin_trylock(&inode->i_lock))) {
- spin_unlock(&dentry->d_lock);
- if (parent)
- spin_unlock(&parent->d_lock);
- cpu_relax();
- continue;
- }
- __dentry_kill(dentry);
- dentry = parent;
- }
- }
- }
- static enum lru_status dentry_lru_isolate(struct list_head *item,
- struct list_lru_one *lru, spinlock_t *lru_lock, void *arg)
- {
- struct list_head *freeable = arg;
- struct dentry *dentry = container_of(item, struct dentry, d_lru);
-
- if (!spin_trylock(&dentry->d_lock))
- return LRU_SKIP;
-
- if (dentry->d_lockref.count) {
- d_lru_isolate(lru, dentry);
- spin_unlock(&dentry->d_lock);
- return LRU_REMOVED;
- }
- if (dentry->d_flags & DCACHE_REFERENCED) {
- dentry->d_flags &= ~DCACHE_REFERENCED;
- spin_unlock(&dentry->d_lock);
-
- return LRU_ROTATE;
- }
- d_lru_shrink_move(lru, dentry, freeable);
- spin_unlock(&dentry->d_lock);
- return LRU_REMOVED;
- }
- long prune_dcache_sb(struct super_block *sb, struct shrink_control *sc)
- {
- LIST_HEAD(dispose);
- long freed;
- freed = list_lru_shrink_walk(&sb->s_dentry_lru, sc,
- dentry_lru_isolate, &dispose);
- shrink_dentry_list(&dispose);
- return freed;
- }
- static enum lru_status dentry_lru_isolate_shrink(struct list_head *item,
- struct list_lru_one *lru, spinlock_t *lru_lock, void *arg)
- {
- struct list_head *freeable = arg;
- struct dentry *dentry = container_of(item, struct dentry, d_lru);
-
- if (!spin_trylock(&dentry->d_lock))
- return LRU_SKIP;
- d_lru_shrink_move(lru, dentry, freeable);
- spin_unlock(&dentry->d_lock);
- return LRU_REMOVED;
- }
- void shrink_dcache_sb(struct super_block *sb)
- {
- long freed;
- do {
- LIST_HEAD(dispose);
- freed = list_lru_walk(&sb->s_dentry_lru,
- dentry_lru_isolate_shrink, &dispose, 1024);
- this_cpu_sub(nr_dentry_unused, freed);
- shrink_dentry_list(&dispose);
- cond_resched();
- } while (list_lru_count(&sb->s_dentry_lru) > 0);
- }
- EXPORT_SYMBOL(shrink_dcache_sb);
- enum d_walk_ret {
- D_WALK_CONTINUE,
- D_WALK_QUIT,
- D_WALK_NORETRY,
- D_WALK_SKIP,
- };
- static void d_walk(struct dentry *parent, void *data,
- enum d_walk_ret (*enter)(void *, struct dentry *),
- void (*finish)(void *))
- {
- struct dentry *this_parent;
- struct list_head *next;
- unsigned seq = 0;
- enum d_walk_ret ret;
- bool retry = true;
- again:
- read_seqbegin_or_lock(&rename_lock, &seq);
- this_parent = parent;
- spin_lock(&this_parent->d_lock);
- ret = enter(data, this_parent);
- switch (ret) {
- case D_WALK_CONTINUE:
- break;
- case D_WALK_QUIT:
- case D_WALK_SKIP:
- goto out_unlock;
- case D_WALK_NORETRY:
- retry = false;
- break;
- }
- repeat:
- next = this_parent->d_subdirs.next;
- resume:
- while (next != &this_parent->d_subdirs) {
- struct list_head *tmp = next;
- struct dentry *dentry = list_entry(tmp, struct dentry, d_child);
- next = tmp->next;
- if (unlikely(dentry->d_flags & DCACHE_DENTRY_CURSOR))
- continue;
- spin_lock_nested(&dentry->d_lock, DENTRY_D_LOCK_NESTED);
- ret = enter(data, dentry);
- switch (ret) {
- case D_WALK_CONTINUE:
- break;
- case D_WALK_QUIT:
- spin_unlock(&dentry->d_lock);
- goto out_unlock;
- case D_WALK_NORETRY:
- retry = false;
- break;
- case D_WALK_SKIP:
- spin_unlock(&dentry->d_lock);
- continue;
- }
- if (!list_empty(&dentry->d_subdirs)) {
- spin_unlock(&this_parent->d_lock);
- spin_release(&dentry->d_lock.dep_map, 1, _RET_IP_);
- this_parent = dentry;
- spin_acquire(&this_parent->d_lock.dep_map, 0, 1, _RET_IP_);
- goto repeat;
- }
- spin_unlock(&dentry->d_lock);
- }
-
- rcu_read_lock();
- ascend:
- if (this_parent != parent) {
- struct dentry *child = this_parent;
- this_parent = child->d_parent;
- spin_unlock(&child->d_lock);
- spin_lock(&this_parent->d_lock);
-
- if (need_seqretry(&rename_lock, seq))
- goto rename_retry;
-
- do {
- next = child->d_child.next;
- if (next == &this_parent->d_subdirs)
- goto ascend;
- child = list_entry(next, struct dentry, d_child);
- } while (unlikely(child->d_flags & DCACHE_DENTRY_KILLED));
- rcu_read_unlock();
- goto resume;
- }
- if (need_seqretry(&rename_lock, seq))
- goto rename_retry;
- rcu_read_unlock();
- if (finish)
- finish(data);
- out_unlock:
- spin_unlock(&this_parent->d_lock);
- done_seqretry(&rename_lock, seq);
- return;
- rename_retry:
- spin_unlock(&this_parent->d_lock);
- rcu_read_unlock();
- BUG_ON(seq & 1);
- if (!retry)
- return;
- seq = 1;
- goto again;
- }
- static enum d_walk_ret check_mount(void *data, struct dentry *dentry)
- {
- int *ret = data;
- if (d_mountpoint(dentry)) {
- *ret = 1;
- return D_WALK_QUIT;
- }
- return D_WALK_CONTINUE;
- }
- int have_submounts(struct dentry *parent)
- {
- int ret = 0;
- d_walk(parent, &ret, check_mount, NULL);
- return ret;
- }
- EXPORT_SYMBOL(have_submounts);
- int d_set_mounted(struct dentry *dentry)
- {
- struct dentry *p;
- int ret = -ENOENT;
- write_seqlock(&rename_lock);
- for (p = dentry->d_parent; !IS_ROOT(p); p = p->d_parent) {
-
- spin_lock(&p->d_lock);
- if (unlikely(d_unhashed(p))) {
- spin_unlock(&p->d_lock);
- goto out;
- }
- spin_unlock(&p->d_lock);
- }
- spin_lock(&dentry->d_lock);
- if (!d_unlinked(dentry)) {
- ret = -EBUSY;
- if (!d_mountpoint(dentry)) {
- dentry->d_flags |= DCACHE_MOUNTED;
- ret = 0;
- }
- }
- spin_unlock(&dentry->d_lock);
- out:
- write_sequnlock(&rename_lock);
- return ret;
- }
- struct select_data {
- struct dentry *start;
- struct list_head dispose;
- int found;
- };
- static enum d_walk_ret select_collect(void *_data, struct dentry *dentry)
- {
- struct select_data *data = _data;
- enum d_walk_ret ret = D_WALK_CONTINUE;
- if (data->start == dentry)
- goto out;
- if (dentry->d_flags & DCACHE_SHRINK_LIST) {
- data->found++;
- } else {
- if (dentry->d_flags & DCACHE_LRU_LIST)
- d_lru_del(dentry);
- if (!dentry->d_lockref.count) {
- d_shrink_add(dentry, &data->dispose);
- data->found++;
- }
- }
-
- if (!list_empty(&data->dispose))
- ret = need_resched() ? D_WALK_QUIT : D_WALK_NORETRY;
- out:
- return ret;
- }
- void shrink_dcache_parent(struct dentry *parent)
- {
- for (;;) {
- struct select_data data;
- INIT_LIST_HEAD(&data.dispose);
- data.start = parent;
- data.found = 0;
- d_walk(parent, &data, select_collect, NULL);
- if (!data.found)
- break;
- shrink_dentry_list(&data.dispose);
- cond_resched();
- }
- }
- EXPORT_SYMBOL(shrink_dcache_parent);
- static enum d_walk_ret umount_check(void *_data, struct dentry *dentry)
- {
-
- if (!list_empty(&dentry->d_subdirs))
- return D_WALK_CONTINUE;
-
- if (dentry == _data && dentry->d_lockref.count == 1)
- return D_WALK_CONTINUE;
- printk(KERN_ERR "BUG: Dentry %p{i=%lx,n=%pd} "
- " still in use (%d) [unmount of %s %s]\n",
- dentry,
- dentry->d_inode ?
- dentry->d_inode->i_ino : 0UL,
- dentry,
- dentry->d_lockref.count,
- dentry->d_sb->s_type->name,
- dentry->d_sb->s_id);
- WARN_ON(1);
- return D_WALK_CONTINUE;
- }
- static void do_one_tree(struct dentry *dentry)
- {
- shrink_dcache_parent(dentry);
- d_walk(dentry, dentry, umount_check, NULL);
- d_drop(dentry);
- dput(dentry);
- }
- void shrink_dcache_for_umount(struct super_block *sb)
- {
- struct dentry *dentry;
- WARN(down_read_trylock(&sb->s_umount), "s_umount should've been locked");
- dentry = sb->s_root;
- sb->s_root = NULL;
- do_one_tree(dentry);
- while (!hlist_bl_empty(&sb->s_anon)) {
- dentry = dget(hlist_bl_entry(hlist_bl_first(&sb->s_anon), struct dentry, d_hash));
- do_one_tree(dentry);
- }
- }
- struct detach_data {
- struct select_data select;
- struct dentry *mountpoint;
- };
- static enum d_walk_ret detach_and_collect(void *_data, struct dentry *dentry)
- {
- struct detach_data *data = _data;
- if (d_mountpoint(dentry)) {
- __dget_dlock(dentry);
- data->mountpoint = dentry;
- return D_WALK_QUIT;
- }
- return select_collect(&data->select, dentry);
- }
- static void check_and_drop(void *_data)
- {
- struct detach_data *data = _data;
- if (!data->mountpoint && !data->select.found)
- __d_drop(data->select.start);
- }
- void d_invalidate(struct dentry *dentry)
- {
-
- spin_lock(&dentry->d_lock);
- if (d_unhashed(dentry)) {
- spin_unlock(&dentry->d_lock);
- return;
- }
- spin_unlock(&dentry->d_lock);
-
- if (!dentry->d_inode) {
- d_drop(dentry);
- return;
- }
- for (;;) {
- struct detach_data data;
- data.mountpoint = NULL;
- INIT_LIST_HEAD(&data.select.dispose);
- data.select.start = dentry;
- data.select.found = 0;
- d_walk(dentry, &data, detach_and_collect, check_and_drop);
- if (data.select.found)
- shrink_dentry_list(&data.select.dispose);
- if (data.mountpoint) {
- detach_mounts(data.mountpoint);
- dput(data.mountpoint);
- }
- if (!data.mountpoint && !data.select.found)
- break;
- cond_resched();
- }
- }
- EXPORT_SYMBOL(d_invalidate);
-
- struct dentry *__d_alloc(struct super_block *sb, const struct qstr *name)
- {
- struct dentry *dentry;
- char *dname;
- int err;
- dentry = kmem_cache_alloc(dentry_cache, GFP_KERNEL);
- if (!dentry)
- return NULL;
-
- dentry->d_iname[DNAME_INLINE_LEN-1] = 0;
- if (unlikely(!name)) {
- static const struct qstr anon = QSTR_INIT("/", 1);
- name = &anon;
- dname = dentry->d_iname;
- } else if (name->len > DNAME_INLINE_LEN-1) {
- size_t size = offsetof(struct external_name, name[1]);
- struct external_name *p = kmalloc(size + name->len,
- GFP_KERNEL_ACCOUNT);
- if (!p) {
- kmem_cache_free(dentry_cache, dentry);
- return NULL;
- }
- atomic_set(&p->u.count, 1);
- dname = p->name;
- if (IS_ENABLED(CONFIG_DCACHE_WORD_ACCESS))
- kasan_unpoison_shadow(dname,
- round_up(name->len + 1, sizeof(unsigned long)));
- } else {
- dname = dentry->d_iname;
- }
- dentry->d_name.len = name->len;
- dentry->d_name.hash = name->hash;
- memcpy(dname, name->name, name->len);
- dname[name->len] = 0;
-
- smp_wmb();
- dentry->d_name.name = dname;
- dentry->d_lockref.count = 1;
- dentry->d_flags = 0;
- spin_lock_init(&dentry->d_lock);
- seqcount_init(&dentry->d_seq);
- dentry->d_inode = NULL;
- dentry->d_parent = dentry;
- dentry->d_sb = sb;
- dentry->d_op = NULL;
- dentry->d_fsdata = NULL;
- INIT_HLIST_BL_NODE(&dentry->d_hash);
- INIT_LIST_HEAD(&dentry->d_lru);
- INIT_LIST_HEAD(&dentry->d_subdirs);
- INIT_HLIST_NODE(&dentry->d_u.d_alias);
- INIT_LIST_HEAD(&dentry->d_child);
- d_set_d_op(dentry, dentry->d_sb->s_d_op);
- if (dentry->d_op && dentry->d_op->d_init) {
- err = dentry->d_op->d_init(dentry);
- if (err) {
- if (dname_external(dentry))
- kfree(external_name(dentry));
- kmem_cache_free(dentry_cache, dentry);
- return NULL;
- }
- }
- this_cpu_inc(nr_dentry);
- return dentry;
- }
- struct dentry *d_alloc(struct dentry * parent, const struct qstr *name)
- {
- struct dentry *dentry = __d_alloc(parent->d_sb, name);
- if (!dentry)
- return NULL;
- dentry->d_flags |= DCACHE_RCUACCESS;
- spin_lock(&parent->d_lock);
-
- __dget_dlock(parent);
- dentry->d_parent = parent;
- list_add(&dentry->d_child, &parent->d_subdirs);
- spin_unlock(&parent->d_lock);
- return dentry;
- }
- EXPORT_SYMBOL(d_alloc);
- struct dentry *d_alloc_cursor(struct dentry * parent)
- {
- struct dentry *dentry = __d_alloc(parent->d_sb, NULL);
- if (dentry) {
- dentry->d_flags |= DCACHE_RCUACCESS | DCACHE_DENTRY_CURSOR;
- dentry->d_parent = dget(parent);
- }
- return dentry;
- }
- struct dentry *d_alloc_pseudo(struct super_block *sb, const struct qstr *name)
- {
- return __d_alloc(sb, name);
- }
- EXPORT_SYMBOL(d_alloc_pseudo);
- struct dentry *d_alloc_name(struct dentry *parent, const char *name)
- {
- struct qstr q;
- q.name = name;
- q.hash_len = hashlen_string(parent, name);
- return d_alloc(parent, &q);
- }
- EXPORT_SYMBOL(d_alloc_name);
- void d_set_d_op(struct dentry *dentry, const struct dentry_operations *op)
- {
- WARN_ON_ONCE(dentry->d_op);
- WARN_ON_ONCE(dentry->d_flags & (DCACHE_OP_HASH |
- DCACHE_OP_COMPARE |
- DCACHE_OP_REVALIDATE |
- DCACHE_OP_WEAK_REVALIDATE |
- DCACHE_OP_DELETE |
- DCACHE_OP_REAL));
- dentry->d_op = op;
- if (!op)
- return;
- if (op->d_hash)
- dentry->d_flags |= DCACHE_OP_HASH;
- if (op->d_compare)
- dentry->d_flags |= DCACHE_OP_COMPARE;
- if (op->d_revalidate)
- dentry->d_flags |= DCACHE_OP_REVALIDATE;
- if (op->d_weak_revalidate)
- dentry->d_flags |= DCACHE_OP_WEAK_REVALIDATE;
- if (op->d_delete)
- dentry->d_flags |= DCACHE_OP_DELETE;
- if (op->d_prune)
- dentry->d_flags |= DCACHE_OP_PRUNE;
- if (op->d_real)
- dentry->d_flags |= DCACHE_OP_REAL;
- }
- EXPORT_SYMBOL(d_set_d_op);
- void d_set_fallthru(struct dentry *dentry)
- {
- spin_lock(&dentry->d_lock);
- dentry->d_flags |= DCACHE_FALLTHRU;
- spin_unlock(&dentry->d_lock);
- }
- EXPORT_SYMBOL(d_set_fallthru);
- static unsigned d_flags_for_inode(struct inode *inode)
- {
- unsigned add_flags = DCACHE_REGULAR_TYPE;
- if (!inode)
- return DCACHE_MISS_TYPE;
- if (S_ISDIR(inode->i_mode)) {
- add_flags = DCACHE_DIRECTORY_TYPE;
- if (unlikely(!(inode->i_opflags & IOP_LOOKUP))) {
- if (unlikely(!inode->i_op->lookup))
- add_flags = DCACHE_AUTODIR_TYPE;
- else
- inode->i_opflags |= IOP_LOOKUP;
- }
- goto type_determined;
- }
- if (unlikely(!(inode->i_opflags & IOP_NOFOLLOW))) {
- if (unlikely(inode->i_op->get_link)) {
- add_flags = DCACHE_SYMLINK_TYPE;
- goto type_determined;
- }
- inode->i_opflags |= IOP_NOFOLLOW;
- }
- if (unlikely(!S_ISREG(inode->i_mode)))
- add_flags = DCACHE_SPECIAL_TYPE;
- type_determined:
- if (unlikely(IS_AUTOMOUNT(inode)))
- add_flags |= DCACHE_NEED_AUTOMOUNT;
- return add_flags;
- }
- static void __d_instantiate(struct dentry *dentry, struct inode *inode)
- {
- unsigned add_flags = d_flags_for_inode(inode);
- WARN_ON(d_in_lookup(dentry));
- spin_lock(&dentry->d_lock);
- hlist_add_head(&dentry->d_u.d_alias, &inode->i_dentry);
- raw_write_seqcount_begin(&dentry->d_seq);
- __d_set_inode_and_type(dentry, inode, add_flags);
- raw_write_seqcount_end(&dentry->d_seq);
- fsnotify_update_flags(dentry);
- spin_unlock(&dentry->d_lock);
- }
-
- void d_instantiate(struct dentry *entry, struct inode * inode)
- {
- BUG_ON(!hlist_unhashed(&entry->d_u.d_alias));
- if (inode) {
- security_d_instantiate(entry, inode);
- spin_lock(&inode->i_lock);
- __d_instantiate(entry, inode);
- spin_unlock(&inode->i_lock);
- }
- }
- EXPORT_SYMBOL(d_instantiate);
- void d_instantiate_new(struct dentry *entry, struct inode *inode)
- {
- BUG_ON(!hlist_unhashed(&entry->d_u.d_alias));
- BUG_ON(!inode);
- lockdep_annotate_inode_mutex_key(inode);
- security_d_instantiate(entry, inode);
- spin_lock(&inode->i_lock);
- __d_instantiate(entry, inode);
- WARN_ON(!(inode->i_state & I_NEW));
- inode->i_state &= ~I_NEW;
- smp_mb();
- wake_up_bit(&inode->i_state, __I_NEW);
- spin_unlock(&inode->i_lock);
- }
- EXPORT_SYMBOL(d_instantiate_new);
- int d_instantiate_no_diralias(struct dentry *entry, struct inode *inode)
- {
- BUG_ON(!hlist_unhashed(&entry->d_u.d_alias));
- security_d_instantiate(entry, inode);
- spin_lock(&inode->i_lock);
- if (S_ISDIR(inode->i_mode) && !hlist_empty(&inode->i_dentry)) {
- spin_unlock(&inode->i_lock);
- iput(inode);
- return -EBUSY;
- }
- __d_instantiate(entry, inode);
- spin_unlock(&inode->i_lock);
- return 0;
- }
- EXPORT_SYMBOL(d_instantiate_no_diralias);
- struct dentry *d_make_root(struct inode *root_inode)
- {
- struct dentry *res = NULL;
- if (root_inode) {
- res = __d_alloc(root_inode->i_sb, NULL);
- if (res)
- d_instantiate(res, root_inode);
- else
- iput(root_inode);
- }
- return res;
- }
- EXPORT_SYMBOL(d_make_root);
- static struct dentry * __d_find_any_alias(struct inode *inode)
- {
- struct dentry *alias;
- if (hlist_empty(&inode->i_dentry))
- return NULL;
- alias = hlist_entry(inode->i_dentry.first, struct dentry, d_u.d_alias);
- __dget(alias);
- return alias;
- }
- struct dentry *d_find_any_alias(struct inode *inode)
- {
- struct dentry *de;
- spin_lock(&inode->i_lock);
- de = __d_find_any_alias(inode);
- spin_unlock(&inode->i_lock);
- return de;
- }
- EXPORT_SYMBOL(d_find_any_alias);
- static struct dentry *__d_obtain_alias(struct inode *inode, int disconnected)
- {
- struct dentry *tmp;
- struct dentry *res;
- unsigned add_flags;
- if (!inode)
- return ERR_PTR(-ESTALE);
- if (IS_ERR(inode))
- return ERR_CAST(inode);
- res = d_find_any_alias(inode);
- if (res)
- goto out_iput;
- tmp = __d_alloc(inode->i_sb, NULL);
- if (!tmp) {
- res = ERR_PTR(-ENOMEM);
- goto out_iput;
- }
- security_d_instantiate(tmp, inode);
- spin_lock(&inode->i_lock);
- res = __d_find_any_alias(inode);
- if (res) {
- spin_unlock(&inode->i_lock);
- dput(tmp);
- goto out_iput;
- }
-
- add_flags = d_flags_for_inode(inode);
- if (disconnected)
- add_flags |= DCACHE_DISCONNECTED;
- spin_lock(&tmp->d_lock);
- __d_set_inode_and_type(tmp, inode, add_flags);
- hlist_add_head(&tmp->d_u.d_alias, &inode->i_dentry);
- hlist_bl_lock(&tmp->d_sb->s_anon);
- hlist_bl_add_head(&tmp->d_hash, &tmp->d_sb->s_anon);
- hlist_bl_unlock(&tmp->d_sb->s_anon);
- spin_unlock(&tmp->d_lock);
- spin_unlock(&inode->i_lock);
- return tmp;
- out_iput:
- iput(inode);
- return res;
- }
- struct dentry *d_obtain_alias(struct inode *inode)
- {
- return __d_obtain_alias(inode, 1);
- }
- EXPORT_SYMBOL(d_obtain_alias);
- struct dentry *d_obtain_root(struct inode *inode)
- {
- return __d_obtain_alias(inode, 0);
- }
- EXPORT_SYMBOL(d_obtain_root);
- struct dentry *d_add_ci(struct dentry *dentry, struct inode *inode,
- struct qstr *name)
- {
- struct dentry *found, *res;
-
- found = d_hash_and_lookup(dentry->d_parent, name);
- if (found) {
- iput(inode);
- return found;
- }
- if (d_in_lookup(dentry)) {
- found = d_alloc_parallel(dentry->d_parent, name,
- dentry->d_wait);
- if (IS_ERR(found) || !d_in_lookup(found)) {
- iput(inode);
- return found;
- }
- } else {
- found = d_alloc(dentry->d_parent, name);
- if (!found) {
- iput(inode);
- return ERR_PTR(-ENOMEM);
- }
- }
- res = d_splice_alias(inode, found);
- if (res) {
- dput(found);
- return res;
- }
- return found;
- }
- EXPORT_SYMBOL(d_add_ci);
- static inline bool d_same_name(const struct dentry *dentry,
- const struct dentry *parent,
- const struct qstr *name)
- {
- if (likely(!(parent->d_flags & DCACHE_OP_COMPARE))) {
- if (dentry->d_name.len != name->len)
- return false;
- return dentry_cmp(dentry, name->name, name->len) == 0;
- }
- return parent->d_op->d_compare(dentry,
- dentry->d_name.len, dentry->d_name.name,
- name) == 0;
- }
- struct dentry *__d_lookup_rcu(const struct dentry *parent,
- const struct qstr *name,
- unsigned *seqp)
- {
- u64 hashlen = name->hash_len;
- const unsigned char *str = name->name;
- struct hlist_bl_head *b = d_hash(hashlen_hash(hashlen));
- struct hlist_bl_node *node;
- struct dentry *dentry;
-
-
- hlist_bl_for_each_entry_rcu(dentry, node, b, d_hash) {
- unsigned seq;
- seqretry:
-
- seq = raw_seqcount_begin(&dentry->d_seq);
- if (dentry->d_parent != parent)
- continue;
- if (d_unhashed(dentry))
- continue;
- if (unlikely(parent->d_flags & DCACHE_OP_COMPARE)) {
- int tlen;
- const char *tname;
- if (dentry->d_name.hash != hashlen_hash(hashlen))
- continue;
- tlen = dentry->d_name.len;
- tname = dentry->d_name.name;
-
- if (read_seqcount_retry(&dentry->d_seq, seq)) {
- cpu_relax();
- goto seqretry;
- }
- if (parent->d_op->d_compare(dentry,
- tlen, tname, name) != 0)
- continue;
- } else {
- if (dentry->d_name.hash_len != hashlen)
- continue;
- if (dentry_cmp(dentry, str, hashlen_len(hashlen)) != 0)
- continue;
- }
- *seqp = seq;
- return dentry;
- }
- return NULL;
- }
- struct dentry *d_lookup(const struct dentry *parent, const struct qstr *name)
- {
- struct dentry *dentry;
- unsigned seq;
- do {
- seq = read_seqbegin(&rename_lock);
- dentry = __d_lookup(parent, name);
- if (dentry)
- break;
- } while (read_seqretry(&rename_lock, seq));
- return dentry;
- }
- EXPORT_SYMBOL(d_lookup);
- struct dentry *__d_lookup(const struct dentry *parent, const struct qstr *name)
- {
- unsigned int hash = name->hash;
- struct hlist_bl_head *b = d_hash(hash);
- struct hlist_bl_node *node;
- struct dentry *found = NULL;
- struct dentry *dentry;
-
-
- rcu_read_lock();
-
- hlist_bl_for_each_entry_rcu(dentry, node, b, d_hash) {
- if (dentry->d_name.hash != hash)
- continue;
- spin_lock(&dentry->d_lock);
- if (dentry->d_parent != parent)
- goto next;
- if (d_unhashed(dentry))
- goto next;
- if (!d_same_name(dentry, parent, name))
- goto next;
- dentry->d_lockref.count++;
- found = dentry;
- spin_unlock(&dentry->d_lock);
- break;
- next:
- spin_unlock(&dentry->d_lock);
- }
- rcu_read_unlock();
- return found;
- }
- struct dentry *d_hash_and_lookup(struct dentry *dir, struct qstr *name)
- {
-
- name->hash = full_name_hash(dir, name->name, name->len);
- if (dir->d_flags & DCACHE_OP_HASH) {
- int err = dir->d_op->d_hash(dir, name);
- if (unlikely(err < 0))
- return ERR_PTR(err);
- }
- return d_lookup(dir, name);
- }
- EXPORT_SYMBOL(d_hash_and_lookup);
-
-
- void d_delete(struct dentry * dentry)
- {
- struct inode *inode;
- int isdir = 0;
-
- again:
- spin_lock(&dentry->d_lock);
- inode = dentry->d_inode;
- isdir = S_ISDIR(inode->i_mode);
- if (dentry->d_lockref.count == 1) {
- if (!spin_trylock(&inode->i_lock)) {
- spin_unlock(&dentry->d_lock);
- cpu_relax();
- goto again;
- }
- dentry->d_flags &= ~DCACHE_CANT_MOUNT;
- dentry_unlink_inode(dentry);
- fsnotify_nameremove(dentry, isdir);
- return;
- }
- if (!d_unhashed(dentry))
- __d_drop(dentry);
- spin_unlock(&dentry->d_lock);
- fsnotify_nameremove(dentry, isdir);
- }
- EXPORT_SYMBOL(d_delete);
- static void __d_rehash(struct dentry *entry)
- {
- struct hlist_bl_head *b = d_hash(entry->d_name.hash);
- hlist_bl_lock(b);
- hlist_bl_add_head_rcu(&entry->d_hash, b);
- hlist_bl_unlock(b);
- }
-
- void d_rehash(struct dentry * entry)
- {
- spin_lock(&entry->d_lock);
- __d_rehash(entry);
- spin_unlock(&entry->d_lock);
- }
- EXPORT_SYMBOL(d_rehash);
- static inline unsigned start_dir_add(struct inode *dir)
- {
- for (;;) {
- unsigned n = dir->i_dir_seq;
- if (!(n & 1) && cmpxchg(&dir->i_dir_seq, n, n + 1) == n)
- return n;
- cpu_relax();
- }
- }
- static inline void end_dir_add(struct inode *dir, unsigned n)
- {
- smp_store_release(&dir->i_dir_seq, n + 2);
- }
- static void d_wait_lookup(struct dentry *dentry)
- {
- if (d_in_lookup(dentry)) {
- DECLARE_WAITQUEUE(wait, current);
- add_wait_queue(dentry->d_wait, &wait);
- do {
- set_current_state(TASK_UNINTERRUPTIBLE);
- spin_unlock(&dentry->d_lock);
- schedule();
- spin_lock(&dentry->d_lock);
- } while (d_in_lookup(dentry));
- }
- }
- struct dentry *d_alloc_parallel(struct dentry *parent,
- const struct qstr *name,
- wait_queue_head_t *wq)
- {
- unsigned int hash = name->hash;
- struct hlist_bl_head *b = in_lookup_hash(parent, hash);
- struct hlist_bl_node *node;
- struct dentry *new = d_alloc(parent, name);
- struct dentry *dentry;
- unsigned seq, r_seq, d_seq;
- if (unlikely(!new))
- return ERR_PTR(-ENOMEM);
- retry:
- rcu_read_lock();
- seq = smp_load_acquire(&parent->d_inode->i_dir_seq);
- r_seq = read_seqbegin(&rename_lock);
- dentry = __d_lookup_rcu(parent, name, &d_seq);
- if (unlikely(dentry)) {
- if (!lockref_get_not_dead(&dentry->d_lockref)) {
- rcu_read_unlock();
- goto retry;
- }
- if (read_seqcount_retry(&dentry->d_seq, d_seq)) {
- rcu_read_unlock();
- dput(dentry);
- goto retry;
- }
- rcu_read_unlock();
- dput(new);
- return dentry;
- }
- if (unlikely(read_seqretry(&rename_lock, r_seq))) {
- rcu_read_unlock();
- goto retry;
- }
- if (unlikely(seq & 1)) {
- rcu_read_unlock();
- goto retry;
- }
- hlist_bl_lock(b);
- if (unlikely(READ_ONCE(parent->d_inode->i_dir_seq) != seq)) {
- hlist_bl_unlock(b);
- rcu_read_unlock();
- goto retry;
- }
-
- hlist_bl_for_each_entry(dentry, node, b, d_u.d_in_lookup_hash) {
- if (dentry->d_name.hash != hash)
- continue;
- if (dentry->d_parent != parent)
- continue;
- if (!d_same_name(dentry, parent, name))
- continue;
- hlist_bl_unlock(b);
-
- if (!lockref_get_not_dead(&dentry->d_lockref)) {
- rcu_read_unlock();
- goto retry;
- }
- rcu_read_unlock();
-
- spin_lock(&dentry->d_lock);
- d_wait_lookup(dentry);
-
- if (unlikely(dentry->d_name.hash != hash))
- goto mismatch;
- if (unlikely(dentry->d_parent != parent))
- goto mismatch;
- if (unlikely(d_unhashed(dentry)))
- goto mismatch;
- if (unlikely(!d_same_name(dentry, parent, name)))
- goto mismatch;
-
- spin_unlock(&dentry->d_lock);
- dput(new);
- return dentry;
- }
- rcu_read_unlock();
-
- new->d_flags |= DCACHE_PAR_LOOKUP;
- new->d_wait = wq;
- hlist_bl_add_head_rcu(&new->d_u.d_in_lookup_hash, b);
- hlist_bl_unlock(b);
- return new;
- mismatch:
- spin_unlock(&dentry->d_lock);
- dput(dentry);
- goto retry;
- }
- EXPORT_SYMBOL(d_alloc_parallel);
- void __d_lookup_done(struct dentry *dentry)
- {
- struct hlist_bl_head *b = in_lookup_hash(dentry->d_parent,
- dentry->d_name.hash);
- hlist_bl_lock(b);
- dentry->d_flags &= ~DCACHE_PAR_LOOKUP;
- __hlist_bl_del(&dentry->d_u.d_in_lookup_hash);
- wake_up_all(dentry->d_wait);
- dentry->d_wait = NULL;
- hlist_bl_unlock(b);
- INIT_HLIST_NODE(&dentry->d_u.d_alias);
- INIT_LIST_HEAD(&dentry->d_lru);
- }
- EXPORT_SYMBOL(__d_lookup_done);
- static inline void __d_add(struct dentry *dentry, struct inode *inode)
- {
- struct inode *dir = NULL;
- unsigned n;
- spin_lock(&dentry->d_lock);
- if (unlikely(d_in_lookup(dentry))) {
- dir = dentry->d_parent->d_inode;
- n = start_dir_add(dir);
- __d_lookup_done(dentry);
- }
- if (inode) {
- unsigned add_flags = d_flags_for_inode(inode);
- hlist_add_head(&dentry->d_u.d_alias, &inode->i_dentry);
- raw_write_seqcount_begin(&dentry->d_seq);
- __d_set_inode_and_type(dentry, inode, add_flags);
- raw_write_seqcount_end(&dentry->d_seq);
- fsnotify_update_flags(dentry);
- }
- __d_rehash(dentry);
- if (dir)
- end_dir_add(dir, n);
- spin_unlock(&dentry->d_lock);
- if (inode)
- spin_unlock(&inode->i_lock);
- }
- void d_add(struct dentry *entry, struct inode *inode)
- {
- if (inode) {
- security_d_instantiate(entry, inode);
- spin_lock(&inode->i_lock);
- }
- __d_add(entry, inode);
- }
- EXPORT_SYMBOL(d_add);
- struct dentry *d_exact_alias(struct dentry *entry, struct inode *inode)
- {
- struct dentry *alias;
- unsigned int hash = entry->d_name.hash;
- spin_lock(&inode->i_lock);
- hlist_for_each_entry(alias, &inode->i_dentry, d_u.d_alias) {
-
- if (alias->d_name.hash != hash)
- continue;
- if (alias->d_parent != entry->d_parent)
- continue;
- if (!d_same_name(alias, entry->d_parent, &entry->d_name))
- continue;
- spin_lock(&alias->d_lock);
- if (!d_unhashed(alias)) {
- spin_unlock(&alias->d_lock);
- alias = NULL;
- } else {
- __dget_dlock(alias);
- __d_rehash(alias);
- spin_unlock(&alias->d_lock);
- }
- spin_unlock(&inode->i_lock);
- return alias;
- }
- spin_unlock(&inode->i_lock);
- return NULL;
- }
- EXPORT_SYMBOL(d_exact_alias);
- void dentry_update_name_case(struct dentry *dentry, const struct qstr *name)
- {
- BUG_ON(!inode_is_locked(dentry->d_parent->d_inode));
- BUG_ON(dentry->d_name.len != name->len);
- spin_lock(&dentry->d_lock);
- write_seqcount_begin(&dentry->d_seq);
- memcpy((unsigned char *)dentry->d_name.name, name->name, name->len);
- write_seqcount_end(&dentry->d_seq);
- spin_unlock(&dentry->d_lock);
- }
- EXPORT_SYMBOL(dentry_update_name_case);
- static void swap_names(struct dentry *dentry, struct dentry *target)
- {
- if (unlikely(dname_external(target))) {
- if (unlikely(dname_external(dentry))) {
-
- swap(target->d_name.name, dentry->d_name.name);
- } else {
-
- memcpy(target->d_iname, dentry->d_name.name,
- dentry->d_name.len + 1);
- dentry->d_name.name = target->d_name.name;
- target->d_name.name = target->d_iname;
- }
- } else {
- if (unlikely(dname_external(dentry))) {
-
- memcpy(dentry->d_iname, target->d_name.name,
- target->d_name.len + 1);
- target->d_name.name = dentry->d_name.name;
- dentry->d_name.name = dentry->d_iname;
- } else {
-
- unsigned int i;
- BUILD_BUG_ON(!IS_ALIGNED(DNAME_INLINE_LEN, sizeof(long)));
- kmemcheck_mark_initialized(dentry->d_iname, DNAME_INLINE_LEN);
- kmemcheck_mark_initialized(target->d_iname, DNAME_INLINE_LEN);
- for (i = 0; i < DNAME_INLINE_LEN / sizeof(long); i++) {
- swap(((long *) &dentry->d_iname)[i],
- ((long *) &target->d_iname)[i]);
- }
- }
- }
- swap(dentry->d_name.hash_len, target->d_name.hash_len);
- }
- static void copy_name(struct dentry *dentry, struct dentry *target)
- {
- struct external_name *old_name = NULL;
- if (unlikely(dname_external(dentry)))
- old_name = external_name(dentry);
- if (unlikely(dname_external(target))) {
- atomic_inc(&external_name(target)->u.count);
- dentry->d_name = target->d_name;
- } else {
- memcpy(dentry->d_iname, target->d_name.name,
- target->d_name.len + 1);
- dentry->d_name.name = dentry->d_iname;
- dentry->d_name.hash_len = target->d_name.hash_len;
- }
- if (old_name && likely(atomic_dec_and_test(&old_name->u.count)))
- kfree_rcu(old_name, u.head);
- }
- static void dentry_lock_for_move(struct dentry *dentry, struct dentry *target)
- {
-
- if (IS_ROOT(dentry) || dentry->d_parent == target->d_parent)
- spin_lock(&target->d_parent->d_lock);
- else {
- if (d_ancestor(dentry->d_parent, target->d_parent)) {
- spin_lock(&dentry->d_parent->d_lock);
- spin_lock_nested(&target->d_parent->d_lock,
- DENTRY_D_LOCK_NESTED);
- } else {
- spin_lock(&target->d_parent->d_lock);
- spin_lock_nested(&dentry->d_parent->d_lock,
- DENTRY_D_LOCK_NESTED);
- }
- }
- if (target < dentry) {
- spin_lock_nested(&target->d_lock, 2);
- spin_lock_nested(&dentry->d_lock, 3);
- } else {
- spin_lock_nested(&dentry->d_lock, 2);
- spin_lock_nested(&target->d_lock, 3);
- }
- }
- static void dentry_unlock_for_move(struct dentry *dentry, struct dentry *target)
- {
- if (target->d_parent != dentry->d_parent)
- spin_unlock(&dentry->d_parent->d_lock);
- if (target->d_parent != target)
- spin_unlock(&target->d_parent->d_lock);
- spin_unlock(&target->d_lock);
- spin_unlock(&dentry->d_lock);
- }
- static void __d_move(struct dentry *dentry, struct dentry *target,
- bool exchange)
- {
- struct inode *dir = NULL;
- unsigned n;
- if (!dentry->d_inode)
- printk(KERN_WARNING "VFS: moving negative dcache entry\n");
- BUG_ON(d_ancestor(dentry, target));
- BUG_ON(d_ancestor(target, dentry));
- dentry_lock_for_move(dentry, target);
- if (unlikely(d_in_lookup(target))) {
- dir = target->d_parent->d_inode;
- n = start_dir_add(dir);
- __d_lookup_done(target);
- }
- write_seqcount_begin(&dentry->d_seq);
- write_seqcount_begin_nested(&target->d_seq, DENTRY_D_LOCK_NESTED);
-
-
- ___d_drop(dentry);
- ___d_drop(target);
-
- if (exchange)
- swap_names(dentry, target);
- else
- copy_name(dentry, target);
-
- __d_rehash(dentry);
- if (exchange)
- __d_rehash(target);
- else
- target->d_hash.pprev = NULL;
-
- if (IS_ROOT(dentry)) {
-
- dentry->d_flags |= DCACHE_RCUACCESS;
- dentry->d_parent = target->d_parent;
- target->d_parent = target;
- list_del_init(&target->d_child);
- list_move(&dentry->d_child, &dentry->d_parent->d_subdirs);
- } else {
-
- swap(dentry->d_parent, target->d_parent);
- list_move(&target->d_child, &target->d_parent->d_subdirs);
- list_move(&dentry->d_child, &dentry->d_parent->d_subdirs);
- if (exchange)
- fsnotify_update_flags(target);
- fsnotify_update_flags(dentry);
- }
- write_seqcount_end(&target->d_seq);
- write_seqcount_end(&dentry->d_seq);
- if (dir)
- end_dir_add(dir, n);
- dentry_unlock_for_move(dentry, target);
- }
- void d_move(struct dentry *dentry, struct dentry *target)
- {
- write_seqlock(&rename_lock);
- __d_move(dentry, target, false);
- write_sequnlock(&rename_lock);
- }
- EXPORT_SYMBOL(d_move);
- void d_exchange(struct dentry *dentry1, struct dentry *dentry2)
- {
- write_seqlock(&rename_lock);
- WARN_ON(!dentry1->d_inode);
- WARN_ON(!dentry2->d_inode);
- WARN_ON(IS_ROOT(dentry1));
- WARN_ON(IS_ROOT(dentry2));
- __d_move(dentry1, dentry2, true);
- write_sequnlock(&rename_lock);
- }
- struct dentry *d_ancestor(struct dentry *p1, struct dentry *p2)
- {
- struct dentry *p;
- for (p = p2; !IS_ROOT(p); p = p->d_parent) {
- if (p->d_parent == p1)
- return p;
- }
- return NULL;
- }
- static int __d_unalias(struct inode *inode,
- struct dentry *dentry, struct dentry *alias)
- {
- struct mutex *m1 = NULL;
- struct rw_semaphore *m2 = NULL;
- int ret = -ESTALE;
-
- if (alias->d_parent == dentry->d_parent)
- goto out_unalias;
-
- if (!mutex_trylock(&dentry->d_sb->s_vfs_rename_mutex))
- goto out_err;
- m1 = &dentry->d_sb->s_vfs_rename_mutex;
- if (!inode_trylock_shared(alias->d_parent->d_inode))
- goto out_err;
- m2 = &alias->d_parent->d_inode->i_rwsem;
- out_unalias:
- __d_move(alias, dentry, false);
- ret = 0;
- out_err:
- if (m2)
- up_read(m2);
- if (m1)
- mutex_unlock(m1);
- return ret;
- }
- struct dentry *d_splice_alias(struct inode *inode, struct dentry *dentry)
- {
- if (IS_ERR(inode))
- return ERR_CAST(inode);
- BUG_ON(!d_unhashed(dentry));
- if (!inode)
- goto out;
- security_d_instantiate(dentry, inode);
- spin_lock(&inode->i_lock);
- if (S_ISDIR(inode->i_mode)) {
- struct dentry *new = __d_find_any_alias(inode);
- if (unlikely(new)) {
-
- spin_unlock(&inode->i_lock);
- write_seqlock(&rename_lock);
- if (unlikely(d_ancestor(new, dentry))) {
- write_sequnlock(&rename_lock);
- dput(new);
- new = ERR_PTR(-ELOOP);
- pr_warn_ratelimited(
- "VFS: Lookup of '%s' in %s %s"
- " would have caused loop\n",
- dentry->d_name.name,
- inode->i_sb->s_type->name,
- inode->i_sb->s_id);
- } else if (!IS_ROOT(new)) {
- int err = __d_unalias(inode, dentry, new);
- write_sequnlock(&rename_lock);
- if (err) {
- dput(new);
- new = ERR_PTR(err);
- }
- } else {
- __d_move(new, dentry, false);
- write_sequnlock(&rename_lock);
- }
- iput(inode);
- return new;
- }
- }
- out:
- __d_add(dentry, inode);
- return NULL;
- }
- EXPORT_SYMBOL(d_splice_alias);
- static int prepend(char **buffer, int *buflen, const char *str, int namelen)
- {
- *buflen -= namelen;
- if (*buflen < 0)
- return -ENAMETOOLONG;
- *buffer -= namelen;
- memcpy(*buffer, str, namelen);
- return 0;
- }
- static int prepend_name(char **buffer, int *buflen, const struct qstr *name)
- {
- const char *dname = ACCESS_ONCE(name->name);
- u32 dlen = ACCESS_ONCE(name->len);
- char *p;
- smp_read_barrier_depends();
- *buflen -= dlen + 1;
- if (*buflen < 0)
- return -ENAMETOOLONG;
- p = *buffer -= dlen + 1;
- *p++ = '/';
- while (dlen--) {
- char c = *dname++;
- if (!c)
- break;
- *p++ = c;
- }
- return 0;
- }
- static int prepend_path(const struct path *path,
- const struct path *root,
- char **buffer, int *buflen)
- {
- struct dentry *dentry;
- struct vfsmount *vfsmnt;
- struct mount *mnt;
- int error = 0;
- unsigned seq, m_seq = 0;
- char *bptr;
- int blen;
- rcu_read_lock();
- restart_mnt:
- read_seqbegin_or_lock(&mount_lock, &m_seq);
- seq = 0;
- rcu_read_lock();
- restart:
- bptr = *buffer;
- blen = *buflen;
- error = 0;
- dentry = path->dentry;
- vfsmnt = path->mnt;
- mnt = real_mount(vfsmnt);
- read_seqbegin_or_lock(&rename_lock, &seq);
- while (dentry != root->dentry || vfsmnt != root->mnt) {
- struct dentry * parent;
- if (dentry == vfsmnt->mnt_root || IS_ROOT(dentry)) {
- struct mount *parent = ACCESS_ONCE(mnt->mnt_parent);
-
- if (dentry != vfsmnt->mnt_root) {
- bptr = *buffer;
- blen = *buflen;
- error = 3;
- break;
- }
-
- if (mnt != parent) {
- dentry = ACCESS_ONCE(mnt->mnt_mountpoint);
- mnt = parent;
- vfsmnt = &mnt->mnt;
- continue;
- }
- if (!error)
- error = is_mounted(vfsmnt) ? 1 : 2;
- break;
- }
- parent = dentry->d_parent;
- prefetch(parent);
- error = prepend_name(&bptr, &blen, &dentry->d_name);
- if (error)
- break;
- dentry = parent;
- }
- if (!(seq & 1))
- rcu_read_unlock();
- if (need_seqretry(&rename_lock, seq)) {
- seq = 1;
- goto restart;
- }
- done_seqretry(&rename_lock, seq);
- if (!(m_seq & 1))
- rcu_read_unlock();
- if (need_seqretry(&mount_lock, m_seq)) {
- m_seq = 1;
- goto restart_mnt;
- }
- done_seqretry(&mount_lock, m_seq);
- if (error >= 0 && bptr == *buffer) {
- if (--blen < 0)
- error = -ENAMETOOLONG;
- else
- *--bptr = '/';
- }
- *buffer = bptr;
- *buflen = blen;
- return error;
- }
- char *__d_path(const struct path *path,
- const struct path *root,
- char *buf, int buflen)
- {
- char *res = buf + buflen;
- int error;
- prepend(&res, &buflen, "\0", 1);
- error = prepend_path(path, root, &res, &buflen);
- if (error < 0)
- return ERR_PTR(error);
- if (error > 0)
- return NULL;
- return res;
- }
- char *d_absolute_path(const struct path *path,
- char *buf, int buflen)
- {
- struct path root = {};
- char *res = buf + buflen;
- int error;
- prepend(&res, &buflen, "\0", 1);
- error = prepend_path(path, &root, &res, &buflen);
- if (error > 1)
- error = -EINVAL;
- if (error < 0)
- return ERR_PTR(error);
- return res;
- }
- static int path_with_deleted(const struct path *path,
- const struct path *root,
- char **buf, int *buflen)
- {
- prepend(buf, buflen, "\0", 1);
- if (d_unlinked(path->dentry)) {
- int error = prepend(buf, buflen, " (deleted)", 10);
- if (error)
- return error;
- }
- return prepend_path(path, root, buf, buflen);
- }
- static int prepend_unreachable(char **buffer, int *buflen)
- {
- return prepend(buffer, buflen, "(unreachable)", 13);
- }
- static void get_fs_root_rcu(struct fs_struct *fs, struct path *root)
- {
- unsigned seq;
- do {
- seq = read_seqcount_begin(&fs->seq);
- *root = fs->root;
- } while (read_seqcount_retry(&fs->seq, seq));
- }
- char *d_path(const struct path *path, char *buf, int buflen)
- {
- char *res = buf + buflen;
- struct path root;
- int error;
-
- if (path->dentry->d_op && path->dentry->d_op->d_dname &&
- (!IS_ROOT(path->dentry) || path->dentry != path->mnt->mnt_root))
- return path->dentry->d_op->d_dname(path->dentry, buf, buflen);
- rcu_read_lock();
- get_fs_root_rcu(current->fs, &root);
- error = path_with_deleted(path, &root, &res, &buflen);
- rcu_read_unlock();
- if (error < 0)
- res = ERR_PTR(error);
- return res;
- }
- EXPORT_SYMBOL(d_path);
- char *dynamic_dname(struct dentry *dentry, char *buffer, int buflen,
- const char *fmt, ...)
- {
- va_list args;
- char temp[64];
- int sz;
- va_start(args, fmt);
- sz = vsnprintf(temp, sizeof(temp), fmt, args) + 1;
- va_end(args);
- if (sz > sizeof(temp) || sz > buflen)
- return ERR_PTR(-ENAMETOOLONG);
- buffer += buflen - sz;
- return memcpy(buffer, temp, sz);
- }
- char *simple_dname(struct dentry *dentry, char *buffer, int buflen)
- {
- char *end = buffer + buflen;
-
- if (prepend(&end, &buflen, " (deleted)", 11) ||
- prepend(&end, &buflen, dentry->d_name.name, dentry->d_name.len) ||
- prepend(&end, &buflen, "/", 1))
- end = ERR_PTR(-ENAMETOOLONG);
- return end;
- }
- EXPORT_SYMBOL(simple_dname);
- static char *__dentry_path(struct dentry *d, char *buf, int buflen)
- {
- struct dentry *dentry;
- char *end, *retval;
- int len, seq = 0;
- int error = 0;
- if (buflen < 2)
- goto Elong;
- rcu_read_lock();
- restart:
- dentry = d;
- end = buf + buflen;
- len = buflen;
- prepend(&end, &len, "\0", 1);
-
- retval = end-1;
- *retval = '/';
- read_seqbegin_or_lock(&rename_lock, &seq);
- while (!IS_ROOT(dentry)) {
- struct dentry *parent = dentry->d_parent;
- prefetch(parent);
- error = prepend_name(&end, &len, &dentry->d_name);
- if (error)
- break;
- retval = end;
- dentry = parent;
- }
- if (!(seq & 1))
- rcu_read_unlock();
- if (need_seqretry(&rename_lock, seq)) {
- seq = 1;
- goto restart;
- }
- done_seqretry(&rename_lock, seq);
- if (error)
- goto Elong;
- return retval;
- Elong:
- return ERR_PTR(-ENAMETOOLONG);
- }
- char *dentry_path_raw(struct dentry *dentry, char *buf, int buflen)
- {
- return __dentry_path(dentry, buf, buflen);
- }
- EXPORT_SYMBOL(dentry_path_raw);
- char *dentry_path(struct dentry *dentry, char *buf, int buflen)
- {
- char *p = NULL;
- char *retval;
- if (d_unlinked(dentry)) {
- p = buf + buflen;
- if (prepend(&p, &buflen, "//deleted", 10) != 0)
- goto Elong;
- buflen++;
- }
- retval = __dentry_path(dentry, buf, buflen);
- if (!IS_ERR(retval) && p)
- *p = '/';
- return retval;
- Elong:
- return ERR_PTR(-ENAMETOOLONG);
- }
- static void get_fs_root_and_pwd_rcu(struct fs_struct *fs, struct path *root,
- struct path *pwd)
- {
- unsigned seq;
- do {
- seq = read_seqcount_begin(&fs->seq);
- *root = fs->root;
- *pwd = fs->pwd;
- } while (read_seqcount_retry(&fs->seq, seq));
- }
- SYSCALL_DEFINE2(getcwd, char __user *, buf, unsigned long, size)
- {
- int error;
- struct path pwd, root;
- char *page = __getname();
- if (!page)
- return -ENOMEM;
- rcu_read_lock();
- get_fs_root_and_pwd_rcu(current->fs, &root, &pwd);
- error = -ENOENT;
- if (!d_unlinked(pwd.dentry)) {
- unsigned long len;
- char *cwd = page + PATH_MAX;
- int buflen = PATH_MAX;
- prepend(&cwd, &buflen, "\0", 1);
- error = prepend_path(&pwd, &root, &cwd, &buflen);
- rcu_read_unlock();
- if (error < 0)
- goto out;
-
- if (error > 0) {
- error = prepend_unreachable(&cwd, &buflen);
- if (error)
- goto out;
- }
- error = -ERANGE;
- len = PATH_MAX + page - cwd;
- if (len <= size) {
- error = len;
- if (copy_to_user(buf, cwd, len))
- error = -EFAULT;
- }
- } else {
- rcu_read_unlock();
- }
- out:
- __putname(page);
- return error;
- }
-
- bool is_subdir(struct dentry *new_dentry, struct dentry *old_dentry)
- {
- bool result;
- unsigned seq;
- if (new_dentry == old_dentry)
- return true;
- do {
-
- seq = read_seqbegin(&rename_lock);
-
- rcu_read_lock();
- if (d_ancestor(old_dentry, new_dentry))
- result = true;
- else
- result = false;
- rcu_read_unlock();
- } while (read_seqretry(&rename_lock, seq));
- return result;
- }
- static enum d_walk_ret d_genocide_kill(void *data, struct dentry *dentry)
- {
- struct dentry *root = data;
- if (dentry != root) {
- if (d_unhashed(dentry) || !dentry->d_inode)
- return D_WALK_SKIP;
- if (!(dentry->d_flags & DCACHE_GENOCIDE)) {
- dentry->d_flags |= DCACHE_GENOCIDE;
- dentry->d_lockref.count--;
- }
- }
- return D_WALK_CONTINUE;
- }
- void d_genocide(struct dentry *parent)
- {
- d_walk(parent, parent, d_genocide_kill, NULL);
- }
- void d_tmpfile(struct dentry *dentry, struct inode *inode)
- {
- inode_dec_link_count(inode);
- BUG_ON(dentry->d_name.name != dentry->d_iname ||
- !hlist_unhashed(&dentry->d_u.d_alias) ||
- !d_unlinked(dentry));
- spin_lock(&dentry->d_parent->d_lock);
- spin_lock_nested(&dentry->d_lock, DENTRY_D_LOCK_NESTED);
- dentry->d_name.len = sprintf(dentry->d_iname, "#%llu",
- (unsigned long long)inode->i_ino);
- spin_unlock(&dentry->d_lock);
- spin_unlock(&dentry->d_parent->d_lock);
- d_instantiate(dentry, inode);
- }
- EXPORT_SYMBOL(d_tmpfile);
- static __initdata unsigned long dhash_entries;
- static int __init set_dhash_entries(char *str)
- {
- if (!str)
- return 0;
- dhash_entries = simple_strtoul(str, &str, 0);
- return 1;
- }
- __setup("dhash_entries=", set_dhash_entries);
- static void __init dcache_init_early(void)
- {
- unsigned int loop;
-
- if (hashdist)
- return;
- dentry_hashtable =
- alloc_large_system_hash("Dentry cache",
- sizeof(struct hlist_bl_head),
- dhash_entries,
- 13,
- HASH_EARLY,
- &d_hash_shift,
- &d_hash_mask,
- 0,
- 0);
- for (loop = 0; loop < (1U << d_hash_shift); loop++)
- INIT_HLIST_BL_HEAD(dentry_hashtable + loop);
- }
- static void __init dcache_init(void)
- {
- unsigned int loop;
-
- dentry_cache = KMEM_CACHE(dentry,
- SLAB_RECLAIM_ACCOUNT|SLAB_PANIC|SLAB_MEM_SPREAD|SLAB_ACCOUNT);
-
- if (!hashdist)
- return;
- dentry_hashtable =
- alloc_large_system_hash("Dentry cache",
- sizeof(struct hlist_bl_head),
- dhash_entries,
- 13,
- 0,
- &d_hash_shift,
- &d_hash_mask,
- 0,
- 0);
- for (loop = 0; loop < (1U << d_hash_shift); loop++)
- INIT_HLIST_BL_HEAD(dentry_hashtable + loop);
- }
- struct kmem_cache *names_cachep __read_mostly;
- EXPORT_SYMBOL(names_cachep);
- EXPORT_SYMBOL(d_genocide);
- void __init vfs_caches_init_early(void)
- {
- dcache_init_early();
- inode_init_early();
- }
- void __init vfs_caches_init(void)
- {
- names_cachep = kmem_cache_create("names_cache", PATH_MAX, 0,
- SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
- dcache_init();
- inode_init();
- files_init();
- files_maxfiles_init();
- mnt_init();
- bdev_cache_init();
- chrdev_init();
- }
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