| #ifndef __LINUX_DCACHE_H |
| #define __LINUX_DCACHE_H |
| |
| #include <linux/atomic.h> |
| #include <linux/list.h> |
| #include <linux/rculist.h> |
| #include <linux/rculist_bl.h> |
| #include <linux/spinlock.h> |
| #include <linux/seqlock.h> |
| #include <linux/cache.h> |
| #include <linux/rcupdate.h> |
| |
| struct nameidata; |
| struct path; |
| struct vfsmount; |
| |
| /* |
| * linux/include/linux/dcache.h |
| * |
| * Dirent cache data structures |
| * |
| * (C) Copyright 1997 Thomas Schoebel-Theuer, |
| * with heavy changes by Linus Torvalds |
| */ |
| |
| #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; |
| #else |
| #define HASH_LEN_DECLARE u32 len; u32 hash; |
| #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)) |
| |
| struct dentry_stat_t { |
| int nr_dentry; |
| int nr_unused; |
| int age_limit; /* age in seconds */ |
| int want_pages; /* pages requested by system */ |
| int dummy[2]; |
| }; |
| extern struct dentry_stat_t dentry_stat; |
| |
| /* Name hashing routines. Initial hash value */ |
| /* Hash courtesy of the R5 hash in reiserfs modulo sign bits */ |
| #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) |
| { |
| return (prevhash + (c << 4) + (c >> 4)) * 11; |
| } |
| |
| /* |
| * 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) |
| { |
| return (unsigned int) hash; |
| } |
| |
| /* Compute the hash for a name string. */ |
| extern unsigned int full_name_hash(const unsigned char *, unsigned int); |
| |
| /* |
| * Try to keep struct dentry aligned on 64 byte cachelines (this will |
| * give reasonable cacheline footprint with larger lines without the |
| * large memory footprint increase). |
| */ |
| #ifdef CONFIG_64BIT |
| # define DNAME_INLINE_LEN 32 /* 192 bytes */ |
| #else |
| # ifdef CONFIG_SMP |
| # define DNAME_INLINE_LEN 36 /* 128 bytes */ |
| # else |
| # define DNAME_INLINE_LEN 40 /* 128 bytes */ |
| # endif |
| #endif |
| |
| struct dentry { |
| /* RCU lookup touched fields */ |
| unsigned int d_flags; /* protected by d_lock */ |
| seqcount_t d_seq; /* per dentry seqlock */ |
| struct hlist_bl_node d_hash; /* lookup hash list */ |
| struct dentry *d_parent; /* parent directory */ |
| struct qstr d_name; |
| struct inode *d_inode; /* Where the name belongs to - NULL is |
| * negative */ |
| unsigned char d_iname[DNAME_INLINE_LEN]; /* small names */ |
| |
| /* Ref lookup also touches following */ |
| unsigned int d_count; /* protected by d_lock */ |
| spinlock_t d_lock; /* per dentry lock */ |
| const struct dentry_operations *d_op; |
| struct super_block *d_sb; /* The root of the dentry tree */ |
| unsigned long d_time; /* used by d_revalidate */ |
| void *d_fsdata; /* fs-specific data */ |
| |
| struct list_head d_lru; /* LRU list */ |
| struct list_head d_child; /* child of parent list */ |
| struct list_head d_subdirs; /* our children */ |
| /* |
| * d_alias and d_rcu can share memory |
| */ |
| union { |
| struct list_head d_alias; /* inode alias list */ |
| struct rcu_head d_rcu; |
| } d_u; |
| }; |
| |
| /* |
| * dentry->d_lock spinlock nesting subclasses: |
| * |
| * 0: normal |
| * 1: nested |
| */ |
| enum dentry_d_lock_class |
| { |
| DENTRY_D_LOCK_NORMAL, /* implicitly used by plain spin_lock() APIs. */ |
| DENTRY_D_LOCK_NESTED |
| }; |
| |
| struct dentry_operations { |
| int (*d_revalidate)(struct dentry *, unsigned int); |
| int (*d_hash)(const struct dentry *, const struct inode *, |
| struct qstr *); |
| int (*d_compare)(const struct dentry *, const struct inode *, |
| const struct dentry *, const struct inode *, |
| unsigned int, const char *, const struct qstr *); |
| int (*d_delete)(const struct dentry *); |
| void (*d_release)(struct dentry *); |
| void (*d_prune)(struct dentry *); |
| void (*d_iput)(struct dentry *, struct inode *); |
| char *(*d_dname)(struct dentry *, char *, int); |
| struct vfsmount *(*d_automount)(struct path *); |
| int (*d_manage)(struct dentry *, bool); |
| void (*d_canonical_path)(const struct path *, struct path *); |
| } ____cacheline_aligned; |
| |
| /* |
| * Locking rules for dentry_operations callbacks are to be found in |
| * Documentation/filesystems/Locking. Keep it updated! |
| * |
| * FUrther descriptions are found in Documentation/filesystems/vfs.txt. |
| * Keep it updated too! |
| */ |
| |
| /* d_flags entries */ |
| #define DCACHE_OP_HASH 0x0001 |
| #define DCACHE_OP_COMPARE 0x0002 |
| #define DCACHE_OP_REVALIDATE 0x0004 |
| #define DCACHE_OP_DELETE 0x0008 |
| #define DCACHE_OP_PRUNE 0x0010 |
| |
| #define DCACHE_DISCONNECTED 0x0020 |
| /* This dentry is possibly not currently connected to the dcache tree, in |
| * which case its parent will either be itself, or will have this flag as |
| * well. nfsd will not use a dentry with this bit set, but will first |
| * endeavour to clear the bit either by discovering that it is connected, |
| * or by performing lookup operations. Any filesystem which supports |
| * nfsd_operations MUST have a lookup function which, if it finds a |
| * directory inode with a DCACHE_DISCONNECTED dentry, will d_move that |
| * dentry into place and return that dentry rather than the passed one, |
| * typically using d_splice_alias. */ |
| |
| #define DCACHE_REFERENCED 0x0040 /* Recently used, don't discard. */ |
| #define DCACHE_RCUACCESS 0x0080 /* Entry has ever been RCU-visible */ |
| |
| #define DCACHE_CANT_MOUNT 0x0100 |
| #define DCACHE_GENOCIDE 0x0200 |
| #define DCACHE_SHRINK_LIST 0x0400 |
| |
| #define DCACHE_NFSFS_RENAMED 0x1000 |
| /* this dentry has been "silly renamed" and has to be deleted on the last |
| * dput() */ |
| #define DCACHE_COOKIE 0x2000 /* For use by dcookie subsystem */ |
| #define DCACHE_FSNOTIFY_PARENT_WATCHED 0x4000 |
| /* Parent inode is watched by some fsnotify listener */ |
| |
| #define DCACHE_MOUNTED 0x10000 /* is a mountpoint */ |
| #define DCACHE_NEED_AUTOMOUNT 0x20000 /* handle automount on this dir */ |
| #define DCACHE_MANAGE_TRANSIT 0x40000 /* manage transit from this dirent */ |
| #define DCACHE_NEED_LOOKUP 0x80000 /* dentry requires i_op->lookup */ |
| #define DCACHE_MANAGED_DENTRY \ |
| (DCACHE_MOUNTED|DCACHE_NEED_AUTOMOUNT|DCACHE_MANAGE_TRANSIT) |
| |
| #define DCACHE_DENTRY_KILLED 0x100000 |
| |
| #define DCACHE_ENCRYPTED_WITH_KEY 0x04000000 /* dir is encrypted with a valid key */ |
| |
| extern seqlock_t rename_lock; |
| |
| static inline int dname_external(struct dentry *dentry) |
| { |
| return dentry->d_name.name != dentry->d_iname; |
| } |
| |
| /* |
| * These are the low-level FS interfaces to the dcache.. |
| */ |
| extern void d_instantiate(struct dentry *, struct inode *); |
| extern struct dentry * d_instantiate_unique(struct dentry *, struct inode *); |
| extern struct dentry * d_materialise_unique(struct dentry *, struct inode *); |
| extern void __d_drop(struct dentry *dentry); |
| extern void d_drop(struct dentry *dentry); |
| extern void d_delete(struct dentry *); |
| extern void d_set_d_op(struct dentry *dentry, const struct dentry_operations *op); |
| |
| /* allocate/de-allocate */ |
| extern struct dentry * d_alloc(struct dentry *, const struct qstr *); |
| extern struct dentry * d_alloc_pseudo(struct super_block *, const struct qstr *); |
| extern struct dentry * d_splice_alias(struct inode *, struct dentry *); |
| extern struct dentry * d_add_ci(struct dentry *, struct inode *, struct qstr *); |
| extern struct dentry *d_find_any_alias(struct inode *inode); |
| extern struct dentry * d_obtain_alias(struct inode *); |
| extern void shrink_dcache_sb(struct super_block *); |
| extern void shrink_dcache_parent(struct dentry *); |
| extern void shrink_dcache_for_umount(struct super_block *); |
| extern int d_invalidate(struct dentry *); |
| |
| /* only used at mount-time */ |
| extern struct dentry * d_make_root(struct inode *); |
| |
| /* <clickety>-<click> the ramfs-type tree */ |
| extern void d_genocide(struct dentry *); |
| |
| extern struct dentry *d_find_alias(struct inode *); |
| extern void d_prune_aliases(struct inode *); |
| |
| /* test whether we have any submounts in a subdir tree */ |
| extern int have_submounts(struct dentry *); |
| |
| /* |
| * This adds the entry to the hash queues. |
| */ |
| extern void d_rehash(struct dentry *); |
| |
| /** |
| * d_add - add dentry to hash queues |
| * @entry: dentry to add |
| * @inode: The inode to attach to this dentry |
| * |
| * This adds the entry to the hash queues and initializes @inode. |
| * The entry was actually filled in earlier during d_alloc(). |
| */ |
| |
| static inline void d_add(struct dentry *entry, struct inode *inode) |
| { |
| d_instantiate(entry, inode); |
| d_rehash(entry); |
| } |
| |
| /** |
| * d_add_unique - add dentry to hash queues without aliasing |
| * @entry: dentry to add |
| * @inode: The inode to attach to this dentry |
| * |
| * This adds the entry to the hash queues and initializes @inode. |
| * The entry was actually filled in earlier during d_alloc(). |
| */ |
| static inline struct dentry *d_add_unique(struct dentry *entry, struct inode *inode) |
| { |
| struct dentry *res; |
| |
| res = d_instantiate_unique(entry, inode); |
| d_rehash(res != NULL ? res : entry); |
| return res; |
| } |
| |
| extern void dentry_update_name_case(struct dentry *, struct qstr *); |
| |
| /* used for rename() and baskets */ |
| extern void d_move(struct dentry *, struct dentry *); |
| extern struct dentry *d_ancestor(struct dentry *, struct dentry *); |
| |
| /* appendix may either be NULL or be used for transname suffixes */ |
| extern struct dentry *d_lookup(const struct dentry *, const struct qstr *); |
| extern struct dentry *d_hash_and_lookup(struct dentry *, struct qstr *); |
| extern struct dentry *__d_lookup(const struct dentry *, const struct qstr *); |
| extern struct dentry *__d_lookup_rcu(const struct dentry *parent, |
| const struct qstr *name, |
| unsigned *seq, struct inode *inode); |
| |
| /** |
| * __d_rcu_to_refcount - take a refcount on dentry if sequence check is ok |
| * @dentry: dentry to take a ref on |
| * @seq: seqcount to verify against |
| * Returns: 0 on failure, else 1. |
| * |
| * __d_rcu_to_refcount operates on a dentry,seq pair that was returned |
| * by __d_lookup_rcu, to get a reference on an rcu-walk dentry. |
| */ |
| static inline int __d_rcu_to_refcount(struct dentry *dentry, unsigned seq) |
| { |
| int ret = 0; |
| |
| assert_spin_locked(&dentry->d_lock); |
| if (!read_seqcount_retry(&dentry->d_seq, seq)) { |
| ret = 1; |
| dentry->d_count++; |
| } |
| |
| return ret; |
| } |
| |
| /* validate "insecure" dentry pointer */ |
| extern int d_validate(struct dentry *, struct dentry *); |
| |
| /* |
| * helper function for dentry_operations.d_dname() members |
| */ |
| extern char *dynamic_dname(struct dentry *, char *, int, const char *, ...); |
| |
| extern char *__d_path(const struct path *, const struct path *, char *, int); |
| extern char *d_absolute_path(const struct path *, char *, int); |
| extern char *d_path(const struct path *, char *, int); |
| extern char *d_path_with_unreachable(const struct path *, char *, int); |
| extern char *dentry_path_raw(struct dentry *, char *, int); |
| extern char *dentry_path(struct dentry *, char *, int); |
| |
| /* Allocation counts.. */ |
| |
| /** |
| * dget, dget_dlock - get a reference to a dentry |
| * @dentry: dentry to get a reference to |
| * |
| * Given a dentry or %NULL pointer increment the reference count |
| * if appropriate and return the dentry. A dentry will not be |
| * destroyed when it has references. |
| */ |
| static inline struct dentry *dget_dlock(struct dentry *dentry) |
| { |
| if (dentry) |
| dentry->d_count++; |
| return dentry; |
| } |
| |
| static inline struct dentry *dget(struct dentry *dentry) |
| { |
| if (dentry) { |
| spin_lock(&dentry->d_lock); |
| dget_dlock(dentry); |
| spin_unlock(&dentry->d_lock); |
| } |
| return dentry; |
| } |
| |
| extern struct dentry *dget_parent(struct dentry *dentry); |
| |
| /** |
| * d_unhashed - is dentry hashed |
| * @dentry: entry to check |
| * |
| * Returns true if the dentry passed is not currently hashed. |
| */ |
| |
| static inline int d_unhashed(struct dentry *dentry) |
| { |
| return hlist_bl_unhashed(&dentry->d_hash); |
| } |
| |
| static inline int d_unlinked(struct dentry *dentry) |
| { |
| return d_unhashed(dentry) && !IS_ROOT(dentry); |
| } |
| |
| static inline int cant_mount(struct dentry *dentry) |
| { |
| return (dentry->d_flags & DCACHE_CANT_MOUNT); |
| } |
| |
| static inline void dont_mount(struct dentry *dentry) |
| { |
| spin_lock(&dentry->d_lock); |
| dentry->d_flags |= DCACHE_CANT_MOUNT; |
| spin_unlock(&dentry->d_lock); |
| } |
| |
| extern void dput(struct dentry *); |
| |
| static inline bool d_managed(struct dentry *dentry) |
| { |
| return dentry->d_flags & DCACHE_MANAGED_DENTRY; |
| } |
| |
| static inline bool d_mountpoint(struct dentry *dentry) |
| { |
| return dentry->d_flags & DCACHE_MOUNTED; |
| } |
| |
| static inline bool d_need_lookup(struct dentry *dentry) |
| { |
| return dentry->d_flags & DCACHE_NEED_LOOKUP; |
| } |
| |
| extern void d_clear_need_lookup(struct dentry *dentry); |
| |
| static inline bool d_is_su(const struct dentry *dentry) |
| { |
| return dentry && |
| dentry->d_name.len == 2 && |
| !memcmp(dentry->d_name.name, "su", 2); |
| } |
| |
| extern int sysctl_vfs_cache_pressure; |
| |
| #endif /* __LINUX_DCACHE_H */ |