linux-phytec-ti

/*

 * fs/dcache.c

 *

 * Complete reimplementation

 * (C) 1997 Thomas Schoebel-Theuer,

 * with heavy changes by Linus Torvalds

 */

​

/*

 * Notes on the allocation strategy:

 *

 * The dcache is a master of the icache - whenever a dcache entry

 * exists, the inode will always exist. "iput()" is done either when

 * the dcache entry is deleted or garbage collected.

 */

​

#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/module.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 "internal.h"

​

int sysctl_vfs_cache_pressure __read_mostly = 100;

EXPORT_SYMBOL_GPL(sysctl_vfs_cache_pressure);

​

 __cacheline_aligned_in_smp DEFINE_SPINLOCK(dcache_lock);

__cacheline_aligned_in_smp DEFINE_SEQLOCK(rename_lock);

​

EXPORT_SYMBOL(dcache_lock);

​

static struct kmem_cache *dentry_cache __read_mostly;

​

#define DNAME_INLINE_LEN (sizeof(struct dentry)-offsetof(struct dentry,d_iname))

​

/*

 * This is the single most critical data structure when it comes

 * to the dcache: the hashtable for lookups. Somebody should try

 * to make this good - I've just made it work.

 *

 * This hash-function tries to avoid losing too many bits of hash

 * information, yet avoid using a prime hash-size or similar.

 */

#define D_HASHBITS     d_hash_shift

#define D_HASHMASK     d_hash_mask

​

static unsigned int d_hash_mask __read_mostly;

static unsigned int d_hash_shift __read_mostly;

static struct hlist_head *dentry_hashtable __read_mostly;

​

/* Statistics gathering. */

struct dentry_stat_t dentry_stat = {

    .age_limit = 45,

};

​

static void __d_free(struct dentry *dentry)

{

    WARN_ON(!list_empty(&dentry->d_alias));

    if (dname_external(dentry))

        kfree(dentry->d_name.name);

    kmem_cache_free(dentry_cache, dentry); 

}

​

static void d_callback(struct rcu_head *head)

{

    struct dentry * dentry = container_of(head, struct dentry, d_u.d_rcu);

    __d_free(dentry);

}

​

/*

 * no dcache_lock, please.  The caller must decrement dentry_stat.nr_dentry

 * inside dcache_lock.

 */

static void d_free(struct dentry *dentry)

{

    if (dentry->d_op && dentry->d_op->d_release)

        dentry->d_op->d_release(dentry);

    /* if dentry was never inserted into hash, immediate free is OK */