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author | Roland McGrath <roland@gnu.org> | 2000-02-04 03:21:18 +0000 |
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committer | Roland McGrath <roland@gnu.org> | 2000-02-04 03:21:18 +0000 |
commit | 8880a73970b23f10c720011cb910c0e0e1e02975 (patch) | |
tree | d1ce76577a1ace5312fc0576a93d4d8db1e89323 /pfinet/linux-src/include/linux/dcache.h | |
parent | 8399aa4ab7b849da57f4c59039f091526c9e2f98 (diff) | |
parent | 9fd51e9b0ad33a89a83fdbbb66bd20d85f7893fb (diff) | |
download | hurd-8880a73970b23f10c720011cb910c0e0e1e02975.tar.gz hurd-8880a73970b23f10c720011cb910c0e0e1e02975.tar.bz2 hurd-8880a73970b23f10c720011cb910c0e0e1e02975.zip |
Merge from vendor branch Linux:
Import of Linux 2.2.12 subset (ipv4 stack and related)
Diffstat (limited to 'pfinet/linux-src/include/linux/dcache.h')
-rw-r--r-- | pfinet/linux-src/include/linux/dcache.h | 194 |
1 files changed, 194 insertions, 0 deletions
diff --git a/pfinet/linux-src/include/linux/dcache.h b/pfinet/linux-src/include/linux/dcache.h new file mode 100644 index 00000000..84e1376b --- /dev/null +++ b/pfinet/linux-src/include/linux/dcache.h @@ -0,0 +1,194 @@ +#ifndef __LINUX_DCACHE_H +#define __LINUX_DCACHE_H + +#ifdef __KERNEL__ + +/* + * linux/include/linux/dcache.h + * + * Dirent cache data structures + * + * (C) Copyright 1997 Thomas Schoebel-Theuer, + * with heavy changes by Linus Torvalds + */ + +#define D_MAXLEN 1024 + +#define IS_ROOT(x) ((x) == (x)->d_parent) + +/* + * "quick string" -- eases parameter passing, but more importantly + * saves "metadata" about the string (ie length and the hash). + */ +struct qstr { + const unsigned char * name; + unsigned int len; + unsigned int hash; +}; + +/* Name hashing routines. Initial hash value */ +#define init_name_hash() 0 + +/* partial hash update function. Assume roughly 4 bits per character */ +static __inline__ unsigned long partial_name_hash(unsigned long c, unsigned long prevhash) +{ + prevhash = (prevhash << 4) | (prevhash >> (8*sizeof(unsigned long)-4)); + return prevhash ^ c; +} + +/* Finally: cut down the number of bits to a int value (and try to avoid losing bits) */ +static __inline__ unsigned long end_name_hash(unsigned long hash) +{ + if (sizeof(hash) > sizeof(unsigned int)) + hash += hash >> 4*sizeof(hash); + return (unsigned int) hash; +} + +/* Compute the hash for a name string. */ +static __inline__ unsigned int full_name_hash(const unsigned char * name, unsigned int len) +{ + unsigned long hash = init_name_hash(); + while (len--) + hash = partial_name_hash(*name++, hash); + return end_name_hash(hash); +} + +#define DNAME_INLINE_LEN 16 + +struct dentry { + int d_count; + unsigned int d_flags; + struct inode * d_inode; /* Where the name belongs to - NULL is negative */ + struct dentry * d_parent; /* parent directory */ + struct dentry * d_mounts; /* mount information */ + struct dentry * d_covers; + struct list_head d_hash; /* lookup hash list */ + struct list_head d_lru; /* d_count = 0 LRU list */ + struct list_head d_child; /* child of parent list */ + struct list_head d_subdirs; /* our children */ + struct list_head d_alias; /* inode alias list */ + struct qstr d_name; + unsigned long d_time; /* used by d_revalidate */ + struct dentry_operations *d_op; + struct super_block * d_sb; /* The root of the dentry tree */ + unsigned long d_reftime; /* last time referenced */ + void * d_fsdata; /* fs-specific data */ + unsigned char d_iname[DNAME_INLINE_LEN]; /* small names */ +}; + +struct dentry_operations { + int (*d_revalidate)(struct dentry *, int); + int (*d_hash) (struct dentry *, struct qstr *); + int (*d_compare) (struct dentry *, struct qstr *, struct qstr *); + void (*d_delete)(struct dentry *); + void (*d_release)(struct dentry *); + void (*d_iput)(struct dentry *, struct inode *); +}; + +/* the dentry parameter passed to d_hash and d_compare is the parent + * directory of the entries to be compared. It is used in case these + * functions need any directory specific information for determining + * equivalency classes. Using the dentry itself might not work, as it + * might be a negative dentry which has no information associated with + * it */ + + + +/* d_flags entries */ +#define DCACHE_AUTOFS_PENDING 0x0001 /* autofs: "under construction" */ +#define DCACHE_NFSFS_RENAMED 0x0002 /* this dentry has been "silly + * renamed" and has to be + * deleted on the last dput() + */ + +/* + * d_drop() unhashes the entry from the parent + * dentry hashes, so that it won't be found through + * a VFS lookup any more. Note that this is different + * from deleting the dentry - d_delete will try to + * mark the dentry negative if possible, giving a + * successful _negative_ lookup, while d_drop will + * just make the cache lookup fail. + * + * d_drop() is used mainly for stuff that wants + * to invalidate a dentry for some reason (NFS + * timeouts or autofs deletes). + */ +static __inline__ void d_drop(struct dentry * dentry) +{ + list_del(&dentry->d_hash); + INIT_LIST_HEAD(&dentry->d_hash); +} + +static __inline__ int dname_external(struct dentry *d) +{ + return d->d_name.name != d->d_iname; +} + +/* + * These are the low-level FS interfaces to the dcache.. + */ +extern void d_instantiate(struct dentry *, struct inode *); +extern void d_delete(struct dentry *); + +/* allocate/de-allocate */ +extern struct dentry * d_alloc(struct dentry * parent, const struct qstr *name); +extern void prune_dcache(int); +extern void shrink_dcache_sb(struct super_block *); +extern void shrink_dcache_parent(struct dentry *); +extern int d_invalidate(struct dentry *); + +#define shrink_dcache() prune_dcache(0) + +/* dcache memory management */ +extern int select_dcache(int, int); +extern void shrink_dcache_memory(int, unsigned int); +extern void check_dcache_memory(void); +extern void free_inode_memory(int); /* defined in fs/inode.c */ + +/* only used at mount-time */ +extern struct dentry * d_alloc_root(struct inode * root_inode, struct dentry * old_root); + +/* test whether root is busy without destroying dcache */ +extern int is_root_busy(struct dentry *); + +/* + * This adds the entry to the hash queues. + */ +extern void d_rehash(struct dentry * entry); +/* + * This adds the entry to the hash queues and initializes "d_inode". + * The entry was actually filled in earlier during "d_alloc()" + */ +static __inline__ void d_add(struct dentry * entry, struct inode * inode) +{ + d_rehash(entry); + d_instantiate(entry, inode); +} + +/* used for rename() and baskets */ +extern void d_move(struct dentry * entry, struct dentry * newdentry); + +/* appendix may either be NULL or be used for transname suffixes */ +extern struct dentry * d_lookup(struct dentry * dir, struct qstr * name); + +/* validate "insecure" dentry pointer */ +extern int d_validate(struct dentry *dentry, struct dentry *dparent, + unsigned int hash, unsigned int len); + +/* write full pathname into buffer and return start of pathname */ +extern char * d_path(struct dentry * entry, char * buf, int buflen); + +/* Allocation counts.. */ +static __inline__ struct dentry * dget(struct dentry *dentry) +{ + if (dentry) + dentry->d_count++; + return dentry; +} + +extern void dput(struct dentry *); + +#endif /* __KERNEL__ */ + +#endif /* __LINUX_DCACHE_H */ |