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Linus Torvalds1da177e2005-04-16 15:20:36 -07001#ifndef __LINUX_DCACHE_H
2#define __LINUX_DCACHE_H
3
Arun Sharma600634972011-07-26 16:09:06 -07004#include <linux/atomic.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -07005#include <linux/list.h>
Franck Bui-Huu82524742008-05-12 21:21:05 +02006#include <linux/rculist.h>
Nick Pigginceb5bdc2011-01-07 17:50:05 +11007#include <linux/rculist_bl.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -07008#include <linux/spinlock.h>
Nick Piggin31e6b012011-01-07 17:49:52 +11009#include <linux/seqlock.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070010#include <linux/cache.h>
11#include <linux/rcupdate.h>
Waiman Long98474232013-08-28 18:24:59 -070012#include <linux/lockref.h>
George Spelvinf4bcbe72016-05-20 07:26:00 -040013#include <linux/stringhash.h>
Ingo Molnarf9411eb2017-02-06 09:50:49 +010014#include <linux/wait.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070015
Jan Blunckcf28b482008-02-14 19:38:44 -080016struct path;
Linus Torvalds1da177e2005-04-16 15:20:36 -070017struct vfsmount;
18
19/*
20 * linux/include/linux/dcache.h
21 *
22 * Dirent cache data structures
23 *
24 * (C) Copyright 1997 Thomas Schoebel-Theuer,
25 * with heavy changes by Linus Torvalds
26 */
27
28#define IS_ROOT(x) ((x) == (x)->d_parent)
29
Linus Torvalds26fe5752012-05-10 13:14:12 -070030/* The hash is always the low bits of hash_len */
31#ifdef __LITTLE_ENDIAN
Andrew Morton2bd03e42016-01-14 15:17:53 -080032 #define HASH_LEN_DECLARE u32 hash; u32 len
Will Deacona5c21dc2013-12-12 17:40:21 +000033 #define bytemask_from_count(cnt) (~(~0ul << (cnt)*8))
Linus Torvalds26fe5752012-05-10 13:14:12 -070034#else
Andrew Morton2bd03e42016-01-14 15:17:53 -080035 #define HASH_LEN_DECLARE u32 len; u32 hash
Will Deacona5c21dc2013-12-12 17:40:21 +000036 #define bytemask_from_count(cnt) (~(~0ul >> (cnt)*8))
Linus Torvalds26fe5752012-05-10 13:14:12 -070037#endif
38
Linus Torvalds1da177e2005-04-16 15:20:36 -070039/*
40 * "quick string" -- eases parameter passing, but more importantly
41 * saves "metadata" about the string (ie length and the hash).
42 *
43 * hash comes first so it snuggles against d_parent in the
44 * dentry.
45 */
46struct qstr {
Linus Torvalds26fe5752012-05-10 13:14:12 -070047 union {
48 struct {
49 HASH_LEN_DECLARE;
50 };
51 u64 hash_len;
52 };
Linus Torvalds1da177e2005-04-16 15:20:36 -070053 const unsigned char *name;
54};
55
Linus Torvalds26fe5752012-05-10 13:14:12 -070056#define QSTR_INIT(n,l) { { { .len = l } }, .name = n }
Linus Torvalds26fe5752012-05-10 13:14:12 -070057
Linus Torvalds1da177e2005-04-16 15:20:36 -070058struct dentry_stat_t {
Glauber Costa3942c072013-08-28 10:17:53 +100059 long nr_dentry;
60 long nr_unused;
61 long age_limit; /* age in seconds */
62 long want_pages; /* pages requested by system */
63 long dummy[2];
Linus Torvalds1da177e2005-04-16 15:20:36 -070064};
65extern struct dentry_stat_t dentry_stat;
66
Nick Pigginc2452f32008-12-01 09:33:43 +010067/*
68 * Try to keep struct dentry aligned on 64 byte cachelines (this will
69 * give reasonable cacheline footprint with larger lines without the
70 * large memory footprint increase).
71 */
72#ifdef CONFIG_64BIT
Nick Piggin44a7d7a2011-01-07 17:49:56 +110073# define DNAME_INLINE_LEN 32 /* 192 bytes */
Nick Pigginc2452f32008-12-01 09:33:43 +010074#else
Nick Piggin44a7d7a2011-01-07 17:49:56 +110075# ifdef CONFIG_SMP
76# define DNAME_INLINE_LEN 36 /* 128 bytes */
77# else
78# define DNAME_INLINE_LEN 40 /* 128 bytes */
79# endif
Nick Pigginc2452f32008-12-01 09:33:43 +010080#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -070081
Waiman Long98474232013-08-28 18:24:59 -070082#define d_lock d_lockref.lock
83
Linus Torvalds1da177e2005-04-16 15:20:36 -070084struct dentry {
Nick Piggin44a7d7a2011-01-07 17:49:56 +110085 /* RCU lookup touched fields */
Linus Torvalds1da177e2005-04-16 15:20:36 -070086 unsigned int d_flags; /* protected by d_lock */
Nick Piggin31e6b012011-01-07 17:49:52 +110087 seqcount_t d_seq; /* per dentry seqlock */
Nick Pigginceb5bdc2011-01-07 17:50:05 +110088 struct hlist_bl_node d_hash; /* lookup hash list */
Linus Torvalds1da177e2005-04-16 15:20:36 -070089 struct dentry *d_parent; /* parent directory */
90 struct qstr d_name;
Nick Piggin44a7d7a2011-01-07 17:49:56 +110091 struct inode *d_inode; /* Where the name belongs to - NULL is
92 * negative */
93 unsigned char d_iname[DNAME_INLINE_LEN]; /* small names */
94
95 /* Ref lookup also touches following */
Waiman Long98474232013-08-28 18:24:59 -070096 struct lockref d_lockref; /* per-dentry lock and refcount */
Nick Piggin44a7d7a2011-01-07 17:49:56 +110097 const struct dentry_operations *d_op;
98 struct super_block *d_sb; /* The root of the dentry tree */
99 unsigned long d_time; /* used by d_revalidate */
100 void *d_fsdata; /* fs-specific data */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700101
Al Virod9171b92016-04-15 03:33:13 -0400102 union {
103 struct list_head d_lru; /* LRU list */
104 wait_queue_head_t *d_wait; /* in-lookup ones only */
105 };
Al Viro946e51f2014-10-26 19:19:16 -0400106 struct list_head d_child; /* child of parent list */
107 struct list_head d_subdirs; /* our children */
Eric Dumazet5160ee62006-01-08 01:03:32 -0800108 /*
Al Viro946e51f2014-10-26 19:19:16 -0400109 * d_alias and d_rcu can share memory
Eric Dumazet5160ee62006-01-08 01:03:32 -0800110 */
111 union {
Al Viro946e51f2014-10-26 19:19:16 -0400112 struct hlist_node d_alias; /* inode alias list */
Al Viro94bdd652016-04-15 02:42:04 -0400113 struct hlist_bl_node d_in_lookup_hash; /* only for in-lookup ones */
Eric Dumazet5160ee62006-01-08 01:03:32 -0800114 struct rcu_head d_rcu;
115 } d_u;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700116};
117
Ingo Molnara90b9c02006-07-03 00:25:04 -0700118/*
119 * dentry->d_lock spinlock nesting subclasses:
120 *
121 * 0: normal
122 * 1: nested
123 */
124enum dentry_d_lock_class
125{
126 DENTRY_D_LOCK_NORMAL, /* implicitly used by plain spin_lock() APIs. */
127 DENTRY_D_LOCK_NESTED
128};
129
Linus Torvalds1da177e2005-04-16 15:20:36 -0700130struct dentry_operations {
Al Viro0b728e12012-06-10 16:03:43 -0400131 int (*d_revalidate)(struct dentry *, unsigned int);
Jeff Laytonecf3d1f2013-02-20 11:19:05 -0500132 int (*d_weak_revalidate)(struct dentry *, unsigned int);
Linus Torvaldsda53be12013-05-21 15:22:44 -0700133 int (*d_hash)(const struct dentry *, struct qstr *);
Al Viro6fa67e72016-07-31 16:37:25 -0400134 int (*d_compare)(const struct dentry *,
Nick Piggin621e1552011-01-07 17:49:27 +1100135 unsigned int, const char *, const struct qstr *);
Nick Pigginfe15ce42011-01-07 17:49:23 +1100136 int (*d_delete)(const struct dentry *);
Miklos Szeredi285b1022016-06-28 11:47:32 +0200137 int (*d_init)(struct dentry *);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700138 void (*d_release)(struct dentry *);
Sage Weilf0023bc2011-10-28 10:02:42 -0700139 void (*d_prune)(struct dentry *);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700140 void (*d_iput)(struct dentry *, struct inode *);
Eric Dumazetc23fbb62007-05-08 00:26:18 -0700141 char *(*d_dname)(struct dentry *, char *, int);
David Howells9875cf82011-01-14 18:45:21 +0000142 struct vfsmount *(*d_automount)(struct path *);
Ian Kentfb5f51c2016-11-24 08:03:41 +1100143 int (*d_manage)(const struct path *, bool);
Miklos Szeredie698b8a2016-06-30 08:53:27 +0200144 struct dentry *(*d_real)(struct dentry *, const struct inode *,
145 unsigned int);
Nick Piggin44a7d7a2011-01-07 17:49:56 +1100146} ____cacheline_aligned;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700147
Nick Piggin5eef7fa2011-01-07 17:49:22 +1100148/*
149 * Locking rules for dentry_operations callbacks are to be found in
150 * Documentation/filesystems/Locking. Keep it updated!
151 *
Nick Piggin621e1552011-01-07 17:49:27 +1100152 * FUrther descriptions are found in Documentation/filesystems/vfs.txt.
153 * Keep it updated too!
Linus Torvalds1da177e2005-04-16 15:20:36 -0700154 */
155
156/* d_flags entries */
David Howellsb18825a2013-09-12 19:22:53 +0100157#define DCACHE_OP_HASH 0x00000001
158#define DCACHE_OP_COMPARE 0x00000002
159#define DCACHE_OP_REVALIDATE 0x00000004
160#define DCACHE_OP_DELETE 0x00000008
161#define DCACHE_OP_PRUNE 0x00000010
Nick Piggin5f57cbc2011-01-07 17:49:54 +1100162
David Howellsb18825a2013-09-12 19:22:53 +0100163#define DCACHE_DISCONNECTED 0x00000020
Nick Piggin5f57cbc2011-01-07 17:49:54 +1100164 /* This dentry is possibly not currently connected to the dcache tree, in
165 * which case its parent will either be itself, or will have this flag as
166 * well. nfsd will not use a dentry with this bit set, but will first
167 * endeavour to clear the bit either by discovering that it is connected,
168 * or by performing lookup operations. Any filesystem which supports
169 * nfsd_operations MUST have a lookup function which, if it finds a
170 * directory inode with a DCACHE_DISCONNECTED dentry, will d_move that
171 * dentry into place and return that dentry rather than the passed one,
172 * typically using d_splice_alias. */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700173
David Howellsb18825a2013-09-12 19:22:53 +0100174#define DCACHE_REFERENCED 0x00000040 /* Recently used, don't discard. */
175#define DCACHE_RCUACCESS 0x00000080 /* Entry has ever been RCU-visible */
Eric Parisc28f7e52009-05-21 17:01:29 -0400176
David Howellsb18825a2013-09-12 19:22:53 +0100177#define DCACHE_CANT_MOUNT 0x00000100
178#define DCACHE_GENOCIDE 0x00000200
179#define DCACHE_SHRINK_LIST 0x00000400
Nick Piggin5f57cbc2011-01-07 17:49:54 +1100180
David Howellsb18825a2013-09-12 19:22:53 +0100181#define DCACHE_OP_WEAK_REVALIDATE 0x00000800
Jeff Laytonecf3d1f2013-02-20 11:19:05 -0500182
David Howellsb18825a2013-09-12 19:22:53 +0100183#define DCACHE_NFSFS_RENAMED 0x00001000
Linus Torvalds830c0f02011-08-06 22:41:50 -0700184 /* this dentry has been "silly renamed" and has to be deleted on the last
185 * dput() */
David Howellsb18825a2013-09-12 19:22:53 +0100186#define DCACHE_COOKIE 0x00002000 /* For use by dcookie subsystem */
187#define DCACHE_FSNOTIFY_PARENT_WATCHED 0x00004000
Linus Torvalds830c0f02011-08-06 22:41:50 -0700188 /* Parent inode is watched by some fsnotify listener */
Nick Pigginfb045ad2011-01-07 17:49:55 +1100189
David Howellsb18825a2013-09-12 19:22:53 +0100190#define DCACHE_DENTRY_KILLED 0x00008000
191
192#define DCACHE_MOUNTED 0x00010000 /* is a mountpoint */
193#define DCACHE_NEED_AUTOMOUNT 0x00020000 /* handle automount on this dir */
194#define DCACHE_MANAGE_TRANSIT 0x00040000 /* manage transit from this dirent */
David Howells9875cf82011-01-14 18:45:21 +0000195#define DCACHE_MANAGED_DENTRY \
David Howellscc53ce52011-01-14 18:45:26 +0000196 (DCACHE_MOUNTED|DCACHE_NEED_AUTOMOUNT|DCACHE_MANAGE_TRANSIT)
David Howells9875cf82011-01-14 18:45:21 +0000197
David Howellsb18825a2013-09-12 19:22:53 +0100198#define DCACHE_LRU_LIST 0x00080000
199
200#define DCACHE_ENTRY_TYPE 0x00700000
David Howellse7f7d222015-01-29 12:02:27 +0000201#define DCACHE_MISS_TYPE 0x00000000 /* Negative dentry (maybe fallthru to nowhere) */
202#define DCACHE_WHITEOUT_TYPE 0x00100000 /* Whiteout dentry (stop pathwalk) */
203#define DCACHE_DIRECTORY_TYPE 0x00200000 /* Normal directory */
204#define DCACHE_AUTODIR_TYPE 0x00300000 /* Lookupless directory (presumed automount) */
David Howells44bdb5e2015-01-29 12:02:29 +0000205#define DCACHE_REGULAR_TYPE 0x00400000 /* Regular file type (or fallthru to such) */
206#define DCACHE_SPECIAL_TYPE 0x00500000 /* Other file type (or fallthru to such) */
207#define DCACHE_SYMLINK_TYPE 0x00600000 /* Symlink (or fallthru to such) */
Miklos Szeredib161dfa62012-09-17 22:31:38 +0200208
Al Viro41edf272014-05-01 10:30:00 -0400209#define DCACHE_MAY_FREE 0x00800000
David Howellsdf1a0852015-01-29 12:02:28 +0000210#define DCACHE_FALLTHRU 0x01000000 /* Fall through to lower layer */
Miklos Szeredi2d902672016-06-30 08:53:27 +0200211#define DCACHE_ENCRYPTED_WITH_KEY 0x02000000 /* dir is encrypted with a valid key */
212#define DCACHE_OP_REAL 0x04000000
Jaegeuk Kim0b81d072015-05-15 16:26:10 -0700213
Al Viro85c7f812016-04-14 19:52:13 -0400214#define DCACHE_PAR_LOOKUP 0x10000000 /* being looked up (with parent locked shared) */
Al Viroba65dc52016-06-10 11:32:47 -0400215#define DCACHE_DENTRY_CURSOR 0x20000000
Al Viro85c7f812016-04-14 19:52:13 -0400216
Al Viro74c3cbe2007-07-22 08:04:18 -0400217extern seqlock_t rename_lock;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700218
Linus Torvalds1da177e2005-04-16 15:20:36 -0700219/*
220 * These are the low-level FS interfaces to the dcache..
221 */
222extern void d_instantiate(struct dentry *, struct inode *);
223extern struct dentry * d_instantiate_unique(struct dentry *, struct inode *);
Miklos Szeredib70a80e2013-10-01 16:44:54 +0200224extern int d_instantiate_no_diralias(struct dentry *, struct inode *);
Nick Piggin789680d2011-01-07 17:49:30 +1100225extern void __d_drop(struct dentry *dentry);
226extern void d_drop(struct dentry *dentry);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700227extern void d_delete(struct dentry *);
Nick Pigginfb045ad2011-01-07 17:49:55 +1100228extern void d_set_d_op(struct dentry *dentry, const struct dentry_operations *op);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700229
230/* allocate/de-allocate */
231extern struct dentry * d_alloc(struct dentry *, const struct qstr *);
Nick Piggin4b936882011-01-07 17:50:07 +1100232extern struct dentry * d_alloc_pseudo(struct super_block *, const struct qstr *);
Al Virod9171b92016-04-15 03:33:13 -0400233extern struct dentry * d_alloc_parallel(struct dentry *, const struct qstr *,
234 wait_queue_head_t *);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700235extern struct dentry * d_splice_alias(struct inode *, struct dentry *);
Christoph Hellwige45b5902008-08-07 23:49:07 +0200236extern struct dentry * d_add_ci(struct dentry *, struct inode *, struct qstr *);
Al Viro668d0cd2016-03-08 12:44:17 -0500237extern struct dentry * d_exact_alias(struct dentry *, struct inode *);
Sage Weil46f72b32012-01-10 09:04:37 -0800238extern struct dentry *d_find_any_alias(struct inode *inode);
Christoph Hellwig4ea3ada2008-08-11 15:48:57 +0200239extern struct dentry * d_obtain_alias(struct inode *);
J. Bruce Fields1a0a3972014-02-14 17:35:37 -0500240extern struct dentry * d_obtain_root(struct inode *);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700241extern void shrink_dcache_sb(struct super_block *);
242extern void shrink_dcache_parent(struct dentry *);
David Howellsc636ebd2006-10-11 01:22:19 -0700243extern void shrink_dcache_for_umount(struct super_block *);
Eric W. Biederman5542aa22014-02-13 09:46:25 -0800244extern void d_invalidate(struct dentry *);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700245
246/* only used at mount-time */
Al Viroadc0e912012-01-08 16:49:21 -0500247extern struct dentry * d_make_root(struct inode *);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700248
249/* <clickety>-<click> the ramfs-type tree */
250extern void d_genocide(struct dentry *);
251
Al Viro60545d02013-06-07 01:20:27 -0400252extern void d_tmpfile(struct dentry *, struct inode *);
253
Linus Torvalds1da177e2005-04-16 15:20:36 -0700254extern struct dentry *d_find_alias(struct inode *);
255extern void d_prune_aliases(struct inode *);
256
257/* test whether we have any submounts in a subdir tree */
Ian Kent01619492016-11-24 08:03:41 +1100258extern int path_has_submounts(const struct path *);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700259
260/*
261 * This adds the entry to the hash queues.
262 */
263extern void d_rehash(struct dentry *);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700264
Al Viro34d0d192016-03-08 21:01:03 -0500265extern void d_add(struct dentry *, struct inode *);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700266
Al Viro9aba36d2016-07-20 22:28:45 -0400267extern void dentry_update_name_case(struct dentry *, const struct qstr *);
Nick Pigginfb2d5b82011-01-07 17:49:26 +1100268
Linus Torvalds1da177e2005-04-16 15:20:36 -0700269/* used for rename() and baskets */
270extern void d_move(struct dentry *, struct dentry *);
Miklos Szeredida1ce062014-04-01 17:08:43 +0200271extern void d_exchange(struct dentry *, struct dentry *);
OGAWA Hirofumie2761a12008-10-16 07:50:28 +0900272extern struct dentry *d_ancestor(struct dentry *, struct dentry *);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700273
274/* appendix may either be NULL or be used for transname suffixes */
Al Viroda2d8452013-01-24 18:29:34 -0500275extern struct dentry *d_lookup(const struct dentry *, const struct qstr *);
Nick Piggin31e6b012011-01-07 17:49:52 +1100276extern struct dentry *d_hash_and_lookup(struct dentry *, struct qstr *);
Al Viroa713ca22013-01-24 18:27:00 -0500277extern struct dentry *__d_lookup(const struct dentry *, const struct qstr *);
Linus Torvalds8966be92012-03-02 14:23:30 -0800278extern struct dentry *__d_lookup_rcu(const struct dentry *parent,
Linus Torvaldsda53be12013-05-21 15:22:44 -0700279 const struct qstr *name, unsigned *seq);
Nick Piggin31e6b012011-01-07 17:49:52 +1100280
Peng Tao24924a22013-07-18 22:09:08 +0800281static inline unsigned d_count(const struct dentry *dentry)
Al Viro84d08fa2013-07-05 18:59:33 +0400282{
Waiman Long98474232013-08-28 18:24:59 -0700283 return dentry->d_lockref.count;
Al Viro84d08fa2013-07-05 18:59:33 +0400284}
285
Eric Dumazetc23fbb62007-05-08 00:26:18 -0700286/*
287 * helper function for dentry_operations.d_dname() members
288 */
Nicolas Iooss8db14862015-07-17 16:23:42 -0700289extern __printf(4, 5)
290char *dynamic_dname(struct dentry *, char *, int, const char *, ...);
Al Viro118b2302013-08-24 12:08:17 -0400291extern char *simple_dname(struct dentry *, char *, int);
Eric Dumazetc23fbb62007-05-08 00:26:18 -0700292
Al Viro02125a82011-12-05 08:43:34 -0500293extern char *__d_path(const struct path *, const struct path *, char *, int);
294extern char *d_absolute_path(const struct path *, char *, int);
Jan Engelhardt20d4fdc2008-06-09 16:40:36 -0700295extern char *d_path(const struct path *, char *, int);
Nick Pigginec2447c2011-01-07 17:49:29 +1100296extern char *dentry_path_raw(struct dentry *, char *, int);
Ram Pai6092d042008-03-27 13:06:20 +0100297extern char *dentry_path(struct dentry *, char *, int);
Jan Blunckcf28b482008-02-14 19:38:44 -0800298
Linus Torvalds1da177e2005-04-16 15:20:36 -0700299/* Allocation counts.. */
300
301/**
Nick Piggindc0474b2011-01-07 17:49:43 +1100302 * dget, dget_dlock - get a reference to a dentry
Linus Torvalds1da177e2005-04-16 15:20:36 -0700303 * @dentry: dentry to get a reference to
304 *
305 * Given a dentry or %NULL pointer increment the reference count
306 * if appropriate and return the dentry. A dentry will not be
Nick Piggindc0474b2011-01-07 17:49:43 +1100307 * destroyed when it has references.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700308 */
Nick Pigginb7ab39f2011-01-07 17:49:32 +1100309static inline struct dentry *dget_dlock(struct dentry *dentry)
310{
Nick Piggindc0474b2011-01-07 17:49:43 +1100311 if (dentry)
Waiman Long98474232013-08-28 18:24:59 -0700312 dentry->d_lockref.count++;
Nick Pigginb7ab39f2011-01-07 17:49:32 +1100313 return dentry;
314}
Nick Piggin2fd6b7f2011-01-07 17:49:34 +1100315
Linus Torvalds1da177e2005-04-16 15:20:36 -0700316static inline struct dentry *dget(struct dentry *dentry)
317{
Waiman Long98474232013-08-28 18:24:59 -0700318 if (dentry)
319 lockref_get(&dentry->d_lockref);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700320 return dentry;
321}
322
Nick Pigginb7ab39f2011-01-07 17:49:32 +1100323extern struct dentry *dget_parent(struct dentry *dentry);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700324
325/**
326 * d_unhashed - is dentry hashed
327 * @dentry: entry to check
328 *
329 * Returns true if the dentry passed is not currently hashed.
330 */
331
Al Virof0d3b3d2013-09-05 12:11:29 -0400332static inline int d_unhashed(const struct dentry *dentry)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700333{
Linus Torvaldsdea36672011-04-24 07:58:46 -0700334 return hlist_bl_unhashed(&dentry->d_hash);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700335}
336
Al Virof0d3b3d2013-09-05 12:11:29 -0400337static inline int d_unlinked(const struct dentry *dentry)
Alexey Dobriyanf3da3922009-05-04 03:32:03 +0400338{
339 return d_unhashed(dentry) && !IS_ROOT(dentry);
340}
341
Al Virof0d3b3d2013-09-05 12:11:29 -0400342static inline int cant_mount(const struct dentry *dentry)
Al Virod83c49f2010-04-30 17:17:09 -0400343{
344 return (dentry->d_flags & DCACHE_CANT_MOUNT);
345}
346
347static inline void dont_mount(struct dentry *dentry)
348{
349 spin_lock(&dentry->d_lock);
350 dentry->d_flags |= DCACHE_CANT_MOUNT;
351 spin_unlock(&dentry->d_lock);
352}
353
Al Viro85c7f812016-04-14 19:52:13 -0400354extern void __d_lookup_done(struct dentry *);
355
356static inline int d_in_lookup(struct dentry *dentry)
357{
358 return dentry->d_flags & DCACHE_PAR_LOOKUP;
359}
360
361static inline void d_lookup_done(struct dentry *dentry)
362{
363 if (unlikely(d_in_lookup(dentry))) {
364 spin_lock(&dentry->d_lock);
365 __d_lookup_done(dentry);
366 spin_unlock(&dentry->d_lock);
367 }
368}
369
Linus Torvalds1da177e2005-04-16 15:20:36 -0700370extern void dput(struct dentry *);
371
Al Virof0d3b3d2013-09-05 12:11:29 -0400372static inline bool d_managed(const struct dentry *dentry)
David Howellscc53ce52011-01-14 18:45:26 +0000373{
374 return dentry->d_flags & DCACHE_MANAGED_DENTRY;
375}
376
Al Virof0d3b3d2013-09-05 12:11:29 -0400377static inline bool d_mountpoint(const struct dentry *dentry)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700378{
Nick Piggin5f57cbc2011-01-07 17:49:54 +1100379 return dentry->d_flags & DCACHE_MOUNTED;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700380}
381
David Howellsb18825a2013-09-12 19:22:53 +0100382/*
383 * Directory cache entry type accessor functions.
384 */
David Howellsb18825a2013-09-12 19:22:53 +0100385static inline unsigned __d_entry_type(const struct dentry *dentry)
386{
Al Viroa528aca2016-02-29 12:12:46 -0500387 return dentry->d_flags & DCACHE_ENTRY_TYPE;
David Howellsb18825a2013-09-12 19:22:53 +0100388}
389
David Howellse7f7d222015-01-29 12:02:27 +0000390static inline bool d_is_miss(const struct dentry *dentry)
391{
392 return __d_entry_type(dentry) == DCACHE_MISS_TYPE;
393}
394
395static inline bool d_is_whiteout(const struct dentry *dentry)
396{
397 return __d_entry_type(dentry) == DCACHE_WHITEOUT_TYPE;
398}
399
Miklos Szeredi44b1d532014-04-01 17:08:41 +0200400static inline bool d_can_lookup(const struct dentry *dentry)
David Howellsb18825a2013-09-12 19:22:53 +0100401{
402 return __d_entry_type(dentry) == DCACHE_DIRECTORY_TYPE;
403}
404
405static inline bool d_is_autodir(const struct dentry *dentry)
406{
407 return __d_entry_type(dentry) == DCACHE_AUTODIR_TYPE;
408}
409
Miklos Szeredi44b1d532014-04-01 17:08:41 +0200410static inline bool d_is_dir(const struct dentry *dentry)
411{
412 return d_can_lookup(dentry) || d_is_autodir(dentry);
413}
414
David Howellsb18825a2013-09-12 19:22:53 +0100415static inline bool d_is_symlink(const struct dentry *dentry)
416{
417 return __d_entry_type(dentry) == DCACHE_SYMLINK_TYPE;
418}
419
David Howells44bdb5e2015-01-29 12:02:29 +0000420static inline bool d_is_reg(const struct dentry *dentry)
421{
422 return __d_entry_type(dentry) == DCACHE_REGULAR_TYPE;
423}
424
425static inline bool d_is_special(const struct dentry *dentry)
426{
427 return __d_entry_type(dentry) == DCACHE_SPECIAL_TYPE;
428}
429
David Howellsb18825a2013-09-12 19:22:53 +0100430static inline bool d_is_file(const struct dentry *dentry)
431{
David Howells44bdb5e2015-01-29 12:02:29 +0000432 return d_is_reg(dentry) || d_is_special(dentry);
David Howellsb18825a2013-09-12 19:22:53 +0100433}
434
435static inline bool d_is_negative(const struct dentry *dentry)
436{
David Howellse7f7d222015-01-29 12:02:27 +0000437 // TODO: check d_is_whiteout(dentry) also.
438 return d_is_miss(dentry);
David Howellsb18825a2013-09-12 19:22:53 +0100439}
440
441static inline bool d_is_positive(const struct dentry *dentry)
442{
443 return !d_is_negative(dentry);
444}
445
David Howells525d27b2015-02-11 13:40:17 +0000446/**
447 * d_really_is_negative - Determine if a dentry is really negative (ignoring fallthroughs)
448 * @dentry: The dentry in question
449 *
450 * Returns true if the dentry represents either an absent name or a name that
451 * doesn't map to an inode (ie. ->d_inode is NULL). The dentry could represent
452 * a true miss, a whiteout that isn't represented by a 0,0 chardev or a
453 * fallthrough marker in an opaque directory.
454 *
455 * Note! (1) This should be used *only* by a filesystem to examine its own
456 * dentries. It should not be used to look at some other filesystem's
457 * dentries. (2) It should also be used in combination with d_inode() to get
458 * the inode. (3) The dentry may have something attached to ->d_lower and the
459 * type field of the flags may be set to something other than miss or whiteout.
460 */
461static inline bool d_really_is_negative(const struct dentry *dentry)
462{
463 return dentry->d_inode == NULL;
464}
465
466/**
467 * d_really_is_positive - Determine if a dentry is really positive (ignoring fallthroughs)
468 * @dentry: The dentry in question
469 *
470 * Returns true if the dentry represents a name that maps to an inode
471 * (ie. ->d_inode is not NULL). The dentry might still represent a whiteout if
472 * that is represented on medium as a 0,0 chardev.
473 *
474 * Note! (1) This should be used *only* by a filesystem to examine its own
475 * dentries. It should not be used to look at some other filesystem's
476 * dentries. (2) It should also be used in combination with d_inode() to get
477 * the inode.
478 */
479static inline bool d_really_is_positive(const struct dentry *dentry)
480{
481 return dentry->d_inode != NULL;
482}
483
Al Virodc3f4192015-05-18 10:10:34 -0400484static inline int simple_positive(struct dentry *dentry)
485{
486 return d_really_is_positive(dentry) && !d_unhashed(dentry);
487}
488
David Howellsdf1a0852015-01-29 12:02:28 +0000489extern void d_set_fallthru(struct dentry *dentry);
490
491static inline bool d_is_fallthru(const struct dentry *dentry)
492{
493 return dentry->d_flags & DCACHE_FALLTHRU;
494}
495
496
Linus Torvalds1da177e2005-04-16 15:20:36 -0700497extern int sysctl_vfs_cache_pressure;
498
Glauber Costa55f841c2013-08-28 10:17:53 +1000499static inline unsigned long vfs_pressure_ratio(unsigned long val)
500{
501 return mult_frac(val, sysctl_vfs_cache_pressure, 100);
502}
David Howells155e35d2015-01-29 12:02:27 +0000503
504/**
505 * d_inode - Get the actual inode of this dentry
506 * @dentry: The dentry to query
507 *
508 * This is the helper normal filesystems should use to get at their own inodes
509 * in their own dentries and ignore the layering superimposed upon them.
510 */
511static inline struct inode *d_inode(const struct dentry *dentry)
512{
513 return dentry->d_inode;
514}
515
516/**
517 * d_inode_rcu - Get the actual inode of this dentry with ACCESS_ONCE()
518 * @dentry: The dentry to query
519 *
520 * This is the helper normal filesystems should use to get at their own inodes
521 * in their own dentries and ignore the layering superimposed upon them.
522 */
523static inline struct inode *d_inode_rcu(const struct dentry *dentry)
524{
525 return ACCESS_ONCE(dentry->d_inode);
526}
527
528/**
529 * d_backing_inode - Get upper or lower inode we should be using
530 * @upper: The upper layer
531 *
532 * This is the helper that should be used to get at the inode that will be used
533 * if this dentry were to be opened as a file. The inode may be on the upper
534 * dentry or it may be on a lower dentry pinned by the upper.
535 *
536 * Normal filesystems should not use this to access their own inodes.
537 */
538static inline struct inode *d_backing_inode(const struct dentry *upper)
539{
540 struct inode *inode = upper->d_inode;
541
542 return inode;
543}
544
545/**
546 * d_backing_dentry - Get upper or lower dentry we should be using
547 * @upper: The upper layer
548 *
549 * This is the helper that should be used to get the dentry of the inode that
550 * will be used if this dentry were opened as a file. It may be the upper
551 * dentry or it may be a lower dentry pinned by the upper.
552 *
553 * Normal filesystems should not use this to access their own dentries.
554 */
555static inline struct dentry *d_backing_dentry(struct dentry *upper)
556{
557 return upper;
558}
559
Miklos Szeredie698b8a2016-06-30 08:53:27 +0200560/**
561 * d_real - Return the real dentry
562 * @dentry: the dentry to query
563 * @inode: inode to select the dentry from multiple layers (can be NULL)
564 * @flags: open flags to control copy-up behavior
565 *
Masahiro Yamada03440c42017-02-27 14:28:49 -0800566 * If dentry is on a union/overlay, then return the underlying, real dentry.
Miklos Szeredie698b8a2016-06-30 08:53:27 +0200567 * Otherwise return the dentry itself.
568 *
569 * See also: Documentation/filesystems/vfs.txt
570 */
Miklos Szeredi2d902672016-06-30 08:53:27 +0200571static inline struct dentry *d_real(struct dentry *dentry,
572 const struct inode *inode,
573 unsigned int flags)
Miklos Szeredid101a122016-03-26 16:14:37 -0400574{
575 if (unlikely(dentry->d_flags & DCACHE_OP_REAL))
Miklos Szeredi2d902672016-06-30 08:53:27 +0200576 return dentry->d_op->d_real(dentry, inode, flags);
Miklos Szeredid101a122016-03-26 16:14:37 -0400577 else
578 return dentry;
579}
580
Miklos Szeredia1180842016-05-20 22:13:45 +0200581/**
582 * d_real_inode - Return the real inode
583 * @dentry: The dentry to query
584 *
Masahiro Yamada03440c42017-02-27 14:28:49 -0800585 * If dentry is on a union/overlay, then return the underlying, real inode.
Miklos Szeredia1180842016-05-20 22:13:45 +0200586 * Otherwise return d_inode().
587 */
Miklos Szeredi7b1742e2016-09-16 12:44:20 +0200588static inline struct inode *d_real_inode(const struct dentry *dentry)
Miklos Szeredia1180842016-05-20 22:13:45 +0200589{
Miklos Szeredi7b1742e2016-09-16 12:44:20 +0200590 /* This usage of d_real() results in const dentry */
591 return d_backing_inode(d_real((struct dentry *) dentry, NULL, 0));
Miklos Szeredia1180842016-05-20 22:13:45 +0200592}
593
Miklos Szeredi54d5ca82016-05-11 01:16:37 +0200594
Linus Torvalds1da177e2005-04-16 15:20:36 -0700595#endif /* __LINUX_DCACHE_H */