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#ifndef __LINUX_DCACHE_H
#define __LINUX_DCACHE_H
/*
* linux/include/linux/dcache.h
*
* Dirent cache data structures
*
* (C) Copyright 1997 Thomas Schoebel-Theuer,
* with heavy changes by Linus Torvalds
*/
#include <linux/list.h>
#include <linux/spinlock.h>
#define IS_ROOT(x) ((x) == (x)->d_parent)
/* The hash is always the low bits of hash_len */
#ifdef __LITTLE_ENDIAN
#define HASH_LEN_DECLARE u32 hash; u32 len
#define bytemask_from_count(cnt) (~(~0ul << (cnt)*8))
#else
#define HASH_LEN_DECLARE u32 len; u32 hash
#define bytemask_from_count(cnt) (~(~0ul >> (cnt)*8))
#endif
/*
* "quick string" -- eases parameter passing, but more importantly
* saves "metadata" about the string (ie length and the hash).
*
* hash comes first so it snuggles against d_parent in the
* dentry.
*/
struct qstr {
union {
struct {
HASH_LEN_DECLARE;
};
u64 hash_len;
};
const unsigned char *name;
};
#define QSTR_INIT(n,l) { { { .len = l } }, .name = n }
#define hashlen_hash(hashlen) ((u32) (hashlen))
#define hashlen_len(hashlen) ((u32)((hashlen) >> 32))
#define hashlen_create(hash,len) (((u64)(len)<<32)|(u32)(hash))
#define DNAME_INLINE_LEN_MIN 36
struct dentry {
unsigned int d_flags; /* protected by d_lock */
spinlock_t d_lock; /* per dentry lock */
struct inode *d_inode; /* Where the name belongs to - NULL is
* negative */
unsigned int d_count;
const struct dentry_operations *d_op;
/*
* The next three fields are touched by __d_lookup. Place them here
* so they all fit in a cache line.
*/
struct hlist_node d_hash; /* lookup hash list */
struct dentry *d_parent; /* parent directory */
struct qstr d_name;
struct list_head d_lru; /* LRU list */
/*
* d_child and d_rcu can share memory
*/
struct list_head d_child; /* child of parent list */
struct list_head d_subdirs; /* our children */
unsigned long d_time; /* used by d_revalidate */
struct super_block *d_sb; /* The root of the dentry tree */
void *d_fsdata; /* fs-specific data */
#ifdef CONFIG_PROFILING
struct dcookie_struct *d_cookie; /* cookie, if any */
#endif
int d_mounted;
unsigned char *name; /* all names */
};
struct dentry_operations {
int (*d_revalidate)(struct dentry *, unsigned int);
};
struct dentry * d_make_root(struct inode *);
void d_add(struct dentry *, struct inode *);
struct dentry * d_alloc_anon(struct super_block *);
void d_set_d_op(struct dentry *dentry, const struct dentry_operations *op);
void d_instantiate(struct dentry *dentry, struct inode *inode);
void d_delete(struct dentry *);
struct dentry *dget(struct dentry *);
void dput(struct dentry *);
#define DCACHE_OP_REVALIDATE 0x00000004
#define DCACHE_ENTRY_TYPE 0x00700000
#define DCACHE_MISS_TYPE 0x00000000 /* Negative dentry (maybe fallthru to nowhere) */
#define DCACHE_WHITEOUT_TYPE 0x00100000 /* Whiteout dentry (stop pathwalk) */
#define DCACHE_DIRECTORY_TYPE 0x00200000 /* Normal directory */
#define DCACHE_AUTODIR_TYPE 0x00300000 /* Lookupless directory (presumed automount) */
#define DCACHE_REGULAR_TYPE 0x00400000 /* Regular file type (or fallthru to such) */
#define DCACHE_SPECIAL_TYPE 0x00500000 /* Other file type (or fallthru to such) */
#define DCACHE_SYMLINK_TYPE 0x00600000 /* Symlink (or fallthru to such) */
#define DCACHE_FALLTHRU 0x01000000 /* Fall through to lower layer */
#define DCACHE_CANT_MOUNT 0x00000100
#define DCACHE_MOUNTED 0x00010000 /* is a mountpoint */
#define DCACHE_NEED_AUTOMOUNT 0x00020000 /* handle automount on this dir */
#define DCACHE_MANAGED_DENTRY \
(DCACHE_MOUNTED|DCACHE_NEED_AUTOMOUNT)
static inline bool d_mountpoint(const struct dentry *dentry)
{
return dentry->d_flags & DCACHE_MOUNTED;
}
/*
* Directory cache entry type accessor functions.
*/
static inline unsigned __d_entry_type(const struct dentry *dentry)
{
return dentry->d_flags & DCACHE_ENTRY_TYPE;
}
static inline bool d_is_miss(const struct dentry *dentry)
{
return __d_entry_type(dentry) == DCACHE_MISS_TYPE;
}
static inline bool d_can_lookup(const struct dentry *dentry)
{
return __d_entry_type(dentry) == DCACHE_DIRECTORY_TYPE;
}
static inline bool d_is_autodir(const struct dentry *dentry)
{
return __d_entry_type(dentry) == DCACHE_AUTODIR_TYPE;
}
static inline bool d_is_dir(const struct dentry *dentry)
{
return d_can_lookup(dentry) || d_is_autodir(dentry);
}
static inline bool d_is_symlink(const struct dentry *dentry)
{
return __d_entry_type(dentry) == DCACHE_SYMLINK_TYPE;
}
static inline bool d_is_reg(const struct dentry *dentry)
{
return __d_entry_type(dentry) == DCACHE_REGULAR_TYPE;
}
static inline bool d_is_special(const struct dentry *dentry)
{
return __d_entry_type(dentry) == DCACHE_SPECIAL_TYPE;
}
static inline bool d_is_file(const struct dentry *dentry)
{
return d_is_reg(dentry) || d_is_special(dentry);
}
static inline bool d_is_negative(const struct dentry *dentry)
{
// TODO: check d_is_whiteout(dentry) also.
return d_is_miss(dentry);
}
static inline bool d_is_positive(const struct dentry *dentry)
{
return !d_is_negative(dentry);
}
static inline struct inode *d_inode(const struct dentry *dentry)
{
return dentry->d_inode;
}
#define IS_ROOT(x) ((x) == (x)->d_parent)
char *dpath(struct dentry *dentry, struct dentry *root);
extern const struct dentry_operations no_revalidate_d_ops;
#endif /* __LINUX_DCACHE_H */
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