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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>
Linus Torvalds1da177e2005-04-16 15:20:36 -070014
Jan Blunckcf28b482008-02-14 19:38:44 -080015struct path;
Linus Torvalds1da177e2005-04-16 15:20:36 -070016struct vfsmount;
17
18/*
19 * linux/include/linux/dcache.h
20 *
21 * Dirent cache data structures
22 *
23 * (C) Copyright 1997 Thomas Schoebel-Theuer,
24 * with heavy changes by Linus Torvalds
25 */
26
27#define IS_ROOT(x) ((x) == (x)->d_parent)
28
Linus Torvalds26fe5752012-05-10 13:14:12 -070029/* The hash is always the low bits of hash_len */
30#ifdef __LITTLE_ENDIAN
Andrew Morton2bd03e42016-01-14 15:17:53 -080031 #define HASH_LEN_DECLARE u32 hash; u32 len
Will Deacona5c21dc2013-12-12 17:40:21 +000032 #define bytemask_from_count(cnt) (~(~0ul << (cnt)*8))
Linus Torvalds26fe5752012-05-10 13:14:12 -070033#else
Andrew Morton2bd03e42016-01-14 15:17:53 -080034 #define HASH_LEN_DECLARE u32 len; u32 hash
Will Deacona5c21dc2013-12-12 17:40:21 +000035 #define bytemask_from_count(cnt) (~(~0ul >> (cnt)*8))
Linus Torvalds26fe5752012-05-10 13:14:12 -070036#endif
37
Linus Torvalds1da177e2005-04-16 15:20:36 -070038/*
39 * "quick string" -- eases parameter passing, but more importantly
40 * saves "metadata" about the string (ie length and the hash).
41 *
42 * hash comes first so it snuggles against d_parent in the
43 * dentry.
44 */
45struct qstr {
Linus Torvalds26fe5752012-05-10 13:14:12 -070046 union {
47 struct {
48 HASH_LEN_DECLARE;
49 };
50 u64 hash_len;
51 };
Linus Torvalds1da177e2005-04-16 15:20:36 -070052 const unsigned char *name;
53};
54
Linus Torvalds26fe5752012-05-10 13:14:12 -070055#define QSTR_INIT(n,l) { { { .len = l } }, .name = n }
Linus Torvalds26fe5752012-05-10 13:14:12 -070056
Linus Torvalds1da177e2005-04-16 15:20:36 -070057struct dentry_stat_t {
Glauber Costa3942c072013-08-28 10:17:53 +100058 long nr_dentry;
59 long nr_unused;
60 long age_limit; /* age in seconds */
61 long want_pages; /* pages requested by system */
62 long dummy[2];
Linus Torvalds1da177e2005-04-16 15:20:36 -070063};
64extern struct dentry_stat_t dentry_stat;
65
Nick Pigginc2452f32008-12-01 09:33:43 +010066/*
67 * Try to keep struct dentry aligned on 64 byte cachelines (this will
68 * give reasonable cacheline footprint with larger lines without the
69 * large memory footprint increase).
70 */
71#ifdef CONFIG_64BIT
Nick Piggin44a7d7a2011-01-07 17:49:56 +110072# define DNAME_INLINE_LEN 32 /* 192 bytes */
Nick Pigginc2452f32008-12-01 09:33:43 +010073#else
Nick Piggin44a7d7a2011-01-07 17:49:56 +110074# ifdef CONFIG_SMP
75# define DNAME_INLINE_LEN 36 /* 128 bytes */
76# else
77# define DNAME_INLINE_LEN 40 /* 128 bytes */
78# endif
Nick Pigginc2452f32008-12-01 09:33:43 +010079#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -070080
Waiman Long98474232013-08-28 18:24:59 -070081#define d_lock d_lockref.lock
82
Linus Torvalds1da177e2005-04-16 15:20:36 -070083struct dentry {
Nick Piggin44a7d7a2011-01-07 17:49:56 +110084 /* RCU lookup touched fields */
Linus Torvalds1da177e2005-04-16 15:20:36 -070085 unsigned int d_flags; /* protected by d_lock */
Nick Piggin31e6b012011-01-07 17:49:52 +110086 seqcount_t d_seq; /* per dentry seqlock */
Nick Pigginceb5bdc2011-01-07 17:50:05 +110087 struct hlist_bl_node d_hash; /* lookup hash list */
Linus Torvalds1da177e2005-04-16 15:20:36 -070088 struct dentry *d_parent; /* parent directory */
89 struct qstr d_name;
Nick Piggin44a7d7a2011-01-07 17:49:56 +110090 struct inode *d_inode; /* Where the name belongs to - NULL is
91 * negative */
92 unsigned char d_iname[DNAME_INLINE_LEN]; /* small names */
93
94 /* Ref lookup also touches following */
Waiman Long98474232013-08-28 18:24:59 -070095 struct lockref d_lockref; /* per-dentry lock and refcount */
Nick Piggin44a7d7a2011-01-07 17:49:56 +110096 const struct dentry_operations *d_op;
97 struct super_block *d_sb; /* The root of the dentry tree */
98 unsigned long d_time; /* used by d_revalidate */
99 void *d_fsdata; /* fs-specific data */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700100
Al Virod9171b92016-04-15 03:33:13 -0400101 union {
102 struct list_head d_lru; /* LRU list */
103 wait_queue_head_t *d_wait; /* in-lookup ones only */
104 };
Al Viro946e51f2014-10-26 19:19:16 -0400105 struct list_head d_child; /* child of parent list */
106 struct list_head d_subdirs; /* our children */
Eric Dumazet5160ee62006-01-08 01:03:32 -0800107 /*
Al Viro946e51f2014-10-26 19:19:16 -0400108 * d_alias and d_rcu can share memory
Eric Dumazet5160ee62006-01-08 01:03:32 -0800109 */
110 union {
Al Viro946e51f2014-10-26 19:19:16 -0400111 struct hlist_node d_alias; /* inode alias list */
Al Viro94bdd652016-04-15 02:42:04 -0400112 struct hlist_bl_node d_in_lookup_hash; /* only for in-lookup ones */
Eric Dumazet5160ee62006-01-08 01:03:32 -0800113 struct rcu_head d_rcu;
114 } d_u;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700115};
116
Ingo Molnara90b9c02006-07-03 00:25:04 -0700117/*
118 * dentry->d_lock spinlock nesting subclasses:
119 *
120 * 0: normal
121 * 1: nested
122 */
123enum dentry_d_lock_class
124{
125 DENTRY_D_LOCK_NORMAL, /* implicitly used by plain spin_lock() APIs. */
126 DENTRY_D_LOCK_NESTED
127};
128
Linus Torvalds1da177e2005-04-16 15:20:36 -0700129struct dentry_operations {
Al Viro0b728e12012-06-10 16:03:43 -0400130 int (*d_revalidate)(struct dentry *, unsigned int);
Jeff Laytonecf3d1f2013-02-20 11:19:05 -0500131 int (*d_weak_revalidate)(struct dentry *, unsigned int);
Linus Torvaldsda53be12013-05-21 15:22:44 -0700132 int (*d_hash)(const struct dentry *, struct qstr *);
Al Viro6fa67e72016-07-31 16:37:25 -0400133 int (*d_compare)(const struct dentry *,
Nick Piggin621e1552011-01-07 17:49:27 +1100134 unsigned int, const char *, const struct qstr *);
Nick Pigginfe15ce42011-01-07 17:49:23 +1100135 int (*d_delete)(const struct dentry *);
Miklos Szeredi285b1022016-06-28 11:47:32 +0200136 int (*d_init)(struct dentry *);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700137 void (*d_release)(struct dentry *);
Sage Weilf0023bc2011-10-28 10:02:42 -0700138 void (*d_prune)(struct dentry *);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700139 void (*d_iput)(struct dentry *, struct inode *);
Eric Dumazetc23fbb62007-05-08 00:26:18 -0700140 char *(*d_dname)(struct dentry *, char *, int);
David Howells9875cf82011-01-14 18:45:21 +0000141 struct vfsmount *(*d_automount)(struct path *);
Al Viro1aed3e42011-03-18 09:09:02 -0400142 int (*d_manage)(struct dentry *, bool);
Miklos Szeredie698b8a2016-06-30 08:53:27 +0200143 struct dentry *(*d_real)(struct dentry *, const struct inode *,
144 unsigned int);
Daniel Rosenberg973117c2016-04-22 00:00:14 -0700145 void (*d_canonical_path)(const struct path *, struct path *);
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 *);
Al Viro2d2d3f12018-05-04 08:23:01 -0400223extern void d_instantiate_new(struct dentry *, struct inode *);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700224extern struct dentry * d_instantiate_unique(struct dentry *, struct inode *);
Miklos Szeredib70a80e2013-10-01 16:44:54 +0200225extern int d_instantiate_no_diralias(struct dentry *, struct inode *);
Nick Piggin789680d2011-01-07 17:49:30 +1100226extern void __d_drop(struct dentry *dentry);
227extern void d_drop(struct dentry *dentry);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700228extern void d_delete(struct dentry *);
Nick Pigginfb045ad2011-01-07 17:49:55 +1100229extern void d_set_d_op(struct dentry *dentry, const struct dentry_operations *op);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700230
231/* allocate/de-allocate */
232extern struct dentry * d_alloc(struct dentry *, const struct qstr *);
Nick Piggin4b936882011-01-07 17:50:07 +1100233extern struct dentry * d_alloc_pseudo(struct super_block *, const struct qstr *);
Al Virod9171b92016-04-15 03:33:13 -0400234extern struct dentry * d_alloc_parallel(struct dentry *, const struct qstr *,
235 wait_queue_head_t *);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700236extern struct dentry * d_splice_alias(struct inode *, struct dentry *);
Christoph Hellwige45b5902008-08-07 23:49:07 +0200237extern struct dentry * d_add_ci(struct dentry *, struct inode *, struct qstr *);
Al Viro668d0cd2016-03-08 12:44:17 -0500238extern struct dentry * d_exact_alias(struct dentry *, struct inode *);
Sage Weil46f72b32012-01-10 09:04:37 -0800239extern struct dentry *d_find_any_alias(struct inode *inode);
Christoph Hellwig4ea3ada2008-08-11 15:48:57 +0200240extern struct dentry * d_obtain_alias(struct inode *);
J. Bruce Fields1a0a3972014-02-14 17:35:37 -0500241extern struct dentry * d_obtain_root(struct inode *);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700242extern void shrink_dcache_sb(struct super_block *);
243extern void shrink_dcache_parent(struct dentry *);
David Howellsc636ebd2006-10-11 01:22:19 -0700244extern void shrink_dcache_for_umount(struct super_block *);
Eric W. Biederman5542aa22014-02-13 09:46:25 -0800245extern void d_invalidate(struct dentry *);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700246
247/* only used at mount-time */
Al Viroadc0e912012-01-08 16:49:21 -0500248extern struct dentry * d_make_root(struct inode *);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700249
250/* <clickety>-<click> the ramfs-type tree */
251extern void d_genocide(struct dentry *);
252
Al Viro60545d02013-06-07 01:20:27 -0400253extern void d_tmpfile(struct dentry *, struct inode *);
254
Linus Torvalds1da177e2005-04-16 15:20:36 -0700255extern struct dentry *d_find_alias(struct inode *);
256extern void d_prune_aliases(struct inode *);
257
258/* test whether we have any submounts in a subdir tree */
259extern int have_submounts(struct dentry *);
260
261/*
262 * This adds the entry to the hash queues.
263 */
264extern void d_rehash(struct dentry *);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700265
Al Viro34d0d192016-03-08 21:01:03 -0500266extern void d_add(struct dentry *, struct inode *);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700267
Al Viro9aba36d2016-07-20 22:28:45 -0400268extern void dentry_update_name_case(struct dentry *, const struct qstr *);
Nick Pigginfb2d5b82011-01-07 17:49:26 +1100269
Linus Torvalds1da177e2005-04-16 15:20:36 -0700270/* used for rename() and baskets */
271extern void d_move(struct dentry *, struct dentry *);
Miklos Szeredida1ce062014-04-01 17:08:43 +0200272extern void d_exchange(struct dentry *, struct dentry *);
OGAWA Hirofumie2761a12008-10-16 07:50:28 +0900273extern struct dentry *d_ancestor(struct dentry *, struct dentry *);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700274
275/* appendix may either be NULL or be used for transname suffixes */
Al Viroda2d8452013-01-24 18:29:34 -0500276extern struct dentry *d_lookup(const struct dentry *, const struct qstr *);
Nick Piggin31e6b012011-01-07 17:49:52 +1100277extern struct dentry *d_hash_and_lookup(struct dentry *, struct qstr *);
Al Viroa713ca22013-01-24 18:27:00 -0500278extern struct dentry *__d_lookup(const struct dentry *, const struct qstr *);
Linus Torvalds8966be92012-03-02 14:23:30 -0800279extern struct dentry *__d_lookup_rcu(const struct dentry *parent,
Linus Torvaldsda53be12013-05-21 15:22:44 -0700280 const struct qstr *name, unsigned *seq);
Nick Piggin31e6b012011-01-07 17:49:52 +1100281
Peng Tao24924a22013-07-18 22:09:08 +0800282static inline unsigned d_count(const struct dentry *dentry)
Al Viro84d08fa2013-07-05 18:59:33 +0400283{
Waiman Long98474232013-08-28 18:24:59 -0700284 return dentry->d_lockref.count;
Al Viro84d08fa2013-07-05 18:59:33 +0400285}
286
Eric Dumazetc23fbb62007-05-08 00:26:18 -0700287/*
288 * helper function for dentry_operations.d_dname() members
289 */
Nicolas Iooss8db14862015-07-17 16:23:42 -0700290extern __printf(4, 5)
291char *dynamic_dname(struct dentry *, char *, int, const char *, ...);
Al Viro118b2302013-08-24 12:08:17 -0400292extern char *simple_dname(struct dentry *, char *, int);
Eric Dumazetc23fbb62007-05-08 00:26:18 -0700293
Al Viro02125a82011-12-05 08:43:34 -0500294extern char *__d_path(const struct path *, const struct path *, char *, int);
295extern char *d_absolute_path(const struct path *, char *, int);
Jan Engelhardt20d4fdc2008-06-09 16:40:36 -0700296extern char *d_path(const struct path *, char *, int);
Nick Pigginec2447c2011-01-07 17:49:29 +1100297extern char *dentry_path_raw(struct dentry *, char *, int);
Ram Pai6092d042008-03-27 13:06:20 +0100298extern char *dentry_path(struct dentry *, char *, int);
Jan Blunckcf28b482008-02-14 19:38:44 -0800299
Linus Torvalds1da177e2005-04-16 15:20:36 -0700300/* Allocation counts.. */
301
302/**
Nick Piggindc0474b2011-01-07 17:49:43 +1100303 * dget, dget_dlock - get a reference to a dentry
Linus Torvalds1da177e2005-04-16 15:20:36 -0700304 * @dentry: dentry to get a reference to
305 *
306 * Given a dentry or %NULL pointer increment the reference count
307 * if appropriate and return the dentry. A dentry will not be
Nick Piggindc0474b2011-01-07 17:49:43 +1100308 * destroyed when it has references.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700309 */
Nick Pigginb7ab39f2011-01-07 17:49:32 +1100310static inline struct dentry *dget_dlock(struct dentry *dentry)
311{
Nick Piggindc0474b2011-01-07 17:49:43 +1100312 if (dentry)
Waiman Long98474232013-08-28 18:24:59 -0700313 dentry->d_lockref.count++;
Nick Pigginb7ab39f2011-01-07 17:49:32 +1100314 return dentry;
315}
Nick Piggin2fd6b7f2011-01-07 17:49:34 +1100316
Linus Torvalds1da177e2005-04-16 15:20:36 -0700317static inline struct dentry *dget(struct dentry *dentry)
318{
Waiman Long98474232013-08-28 18:24:59 -0700319 if (dentry)
320 lockref_get(&dentry->d_lockref);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700321 return dentry;
322}
323
Nick Pigginb7ab39f2011-01-07 17:49:32 +1100324extern struct dentry *dget_parent(struct dentry *dentry);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700325
326/**
327 * d_unhashed - is dentry hashed
328 * @dentry: entry to check
329 *
330 * Returns true if the dentry passed is not currently hashed.
331 */
332
Al Virof0d3b3d2013-09-05 12:11:29 -0400333static inline int d_unhashed(const struct dentry *dentry)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700334{
Linus Torvaldsdea36672011-04-24 07:58:46 -0700335 return hlist_bl_unhashed(&dentry->d_hash);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700336}
337
Al Virof0d3b3d2013-09-05 12:11:29 -0400338static inline int d_unlinked(const struct dentry *dentry)
Alexey Dobriyanf3da3922009-05-04 03:32:03 +0400339{
340 return d_unhashed(dentry) && !IS_ROOT(dentry);
341}
342
Al Virof0d3b3d2013-09-05 12:11:29 -0400343static inline int cant_mount(const struct dentry *dentry)
Al Virod83c49f2010-04-30 17:17:09 -0400344{
345 return (dentry->d_flags & DCACHE_CANT_MOUNT);
346}
347
348static inline void dont_mount(struct dentry *dentry)
349{
350 spin_lock(&dentry->d_lock);
351 dentry->d_flags |= DCACHE_CANT_MOUNT;
352 spin_unlock(&dentry->d_lock);
353}
354
Al Viro85c7f812016-04-14 19:52:13 -0400355extern void __d_lookup_done(struct dentry *);
356
357static inline int d_in_lookup(struct dentry *dentry)
358{
359 return dentry->d_flags & DCACHE_PAR_LOOKUP;
360}
361
362static inline void d_lookup_done(struct dentry *dentry)
363{
364 if (unlikely(d_in_lookup(dentry))) {
365 spin_lock(&dentry->d_lock);
366 __d_lookup_done(dentry);
367 spin_unlock(&dentry->d_lock);
368 }
369}
370
Linus Torvalds1da177e2005-04-16 15:20:36 -0700371extern void dput(struct dentry *);
372
Al Virof0d3b3d2013-09-05 12:11:29 -0400373static inline bool d_managed(const struct dentry *dentry)
David Howellscc53ce52011-01-14 18:45:26 +0000374{
375 return dentry->d_flags & DCACHE_MANAGED_DENTRY;
376}
377
Al Virof0d3b3d2013-09-05 12:11:29 -0400378static inline bool d_mountpoint(const struct dentry *dentry)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700379{
Nick Piggin5f57cbc2011-01-07 17:49:54 +1100380 return dentry->d_flags & DCACHE_MOUNTED;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700381}
382
David Howellsb18825a2013-09-12 19:22:53 +0100383/*
384 * Directory cache entry type accessor functions.
385 */
David Howellsb18825a2013-09-12 19:22:53 +0100386static inline unsigned __d_entry_type(const struct dentry *dentry)
387{
Al Viroa528aca2016-02-29 12:12:46 -0500388 return dentry->d_flags & DCACHE_ENTRY_TYPE;
David Howellsb18825a2013-09-12 19:22:53 +0100389}
390
David Howellse7f7d222015-01-29 12:02:27 +0000391static inline bool d_is_miss(const struct dentry *dentry)
392{
393 return __d_entry_type(dentry) == DCACHE_MISS_TYPE;
394}
395
396static inline bool d_is_whiteout(const struct dentry *dentry)
397{
398 return __d_entry_type(dentry) == DCACHE_WHITEOUT_TYPE;
399}
400
Miklos Szeredi44b1d532014-04-01 17:08:41 +0200401static inline bool d_can_lookup(const struct dentry *dentry)
David Howellsb18825a2013-09-12 19:22:53 +0100402{
403 return __d_entry_type(dentry) == DCACHE_DIRECTORY_TYPE;
404}
405
406static inline bool d_is_autodir(const struct dentry *dentry)
407{
408 return __d_entry_type(dentry) == DCACHE_AUTODIR_TYPE;
409}
410
Miklos Szeredi44b1d532014-04-01 17:08:41 +0200411static inline bool d_is_dir(const struct dentry *dentry)
412{
413 return d_can_lookup(dentry) || d_is_autodir(dentry);
414}
415
David Howellsb18825a2013-09-12 19:22:53 +0100416static inline bool d_is_symlink(const struct dentry *dentry)
417{
418 return __d_entry_type(dentry) == DCACHE_SYMLINK_TYPE;
419}
420
David Howells44bdb5e2015-01-29 12:02:29 +0000421static inline bool d_is_reg(const struct dentry *dentry)
422{
423 return __d_entry_type(dentry) == DCACHE_REGULAR_TYPE;
424}
425
426static inline bool d_is_special(const struct dentry *dentry)
427{
428 return __d_entry_type(dentry) == DCACHE_SPECIAL_TYPE;
429}
430
David Howellsb18825a2013-09-12 19:22:53 +0100431static inline bool d_is_file(const struct dentry *dentry)
432{
David Howells44bdb5e2015-01-29 12:02:29 +0000433 return d_is_reg(dentry) || d_is_special(dentry);
David Howellsb18825a2013-09-12 19:22:53 +0100434}
435
436static inline bool d_is_negative(const struct dentry *dentry)
437{
David Howellse7f7d222015-01-29 12:02:27 +0000438 // TODO: check d_is_whiteout(dentry) also.
439 return d_is_miss(dentry);
David Howellsb18825a2013-09-12 19:22:53 +0100440}
441
442static inline bool d_is_positive(const struct dentry *dentry)
443{
444 return !d_is_negative(dentry);
445}
446
David Howells525d27b2015-02-11 13:40:17 +0000447/**
448 * d_really_is_negative - Determine if a dentry is really negative (ignoring fallthroughs)
449 * @dentry: The dentry in question
450 *
451 * Returns true if the dentry represents either an absent name or a name that
452 * doesn't map to an inode (ie. ->d_inode is NULL). The dentry could represent
453 * a true miss, a whiteout that isn't represented by a 0,0 chardev or a
454 * fallthrough marker in an opaque directory.
455 *
456 * Note! (1) This should be used *only* by a filesystem to examine its own
457 * dentries. It should not be used to look at some other filesystem's
458 * dentries. (2) It should also be used in combination with d_inode() to get
459 * the inode. (3) The dentry may have something attached to ->d_lower and the
460 * type field of the flags may be set to something other than miss or whiteout.
461 */
462static inline bool d_really_is_negative(const struct dentry *dentry)
463{
464 return dentry->d_inode == NULL;
465}
466
467/**
468 * d_really_is_positive - Determine if a dentry is really positive (ignoring fallthroughs)
469 * @dentry: The dentry in question
470 *
471 * Returns true if the dentry represents a name that maps to an inode
472 * (ie. ->d_inode is not NULL). The dentry might still represent a whiteout if
473 * that is represented on medium as a 0,0 chardev.
474 *
475 * Note! (1) This should be used *only* by a filesystem to examine its own
476 * dentries. It should not be used to look at some other filesystem's
477 * dentries. (2) It should also be used in combination with d_inode() to get
478 * the inode.
479 */
480static inline bool d_really_is_positive(const struct dentry *dentry)
481{
482 return dentry->d_inode != NULL;
483}
484
Al Virodc3f4192015-05-18 10:10:34 -0400485static inline int simple_positive(struct dentry *dentry)
486{
487 return d_really_is_positive(dentry) && !d_unhashed(dentry);
488}
489
David Howellsdf1a0852015-01-29 12:02:28 +0000490extern void d_set_fallthru(struct dentry *dentry);
491
492static inline bool d_is_fallthru(const struct dentry *dentry)
493{
494 return dentry->d_flags & DCACHE_FALLTHRU;
495}
496
497
Linus Torvalds1da177e2005-04-16 15:20:36 -0700498extern int sysctl_vfs_cache_pressure;
499
Glauber Costa55f841c2013-08-28 10:17:53 +1000500static inline unsigned long vfs_pressure_ratio(unsigned long val)
501{
502 return mult_frac(val, sysctl_vfs_cache_pressure, 100);
503}
David Howells155e35d2015-01-29 12:02:27 +0000504
505/**
506 * d_inode - Get the actual inode of this dentry
507 * @dentry: The dentry to query
508 *
509 * This is the helper normal filesystems should use to get at their own inodes
510 * in their own dentries and ignore the layering superimposed upon them.
511 */
512static inline struct inode *d_inode(const struct dentry *dentry)
513{
514 return dentry->d_inode;
515}
516
517/**
518 * d_inode_rcu - Get the actual inode of this dentry with ACCESS_ONCE()
519 * @dentry: The dentry to query
520 *
521 * This is the helper normal filesystems should use to get at their own inodes
522 * in their own dentries and ignore the layering superimposed upon them.
523 */
524static inline struct inode *d_inode_rcu(const struct dentry *dentry)
525{
526 return ACCESS_ONCE(dentry->d_inode);
527}
528
529/**
530 * d_backing_inode - Get upper or lower inode we should be using
531 * @upper: The upper layer
532 *
533 * This is the helper that should be used to get at the inode that will be used
534 * if this dentry were to be opened as a file. The inode may be on the upper
535 * dentry or it may be on a lower dentry pinned by the upper.
536 *
537 * Normal filesystems should not use this to access their own inodes.
538 */
539static inline struct inode *d_backing_inode(const struct dentry *upper)
540{
541 struct inode *inode = upper->d_inode;
542
543 return inode;
544}
545
546/**
547 * d_backing_dentry - Get upper or lower dentry we should be using
548 * @upper: The upper layer
549 *
550 * This is the helper that should be used to get the dentry of the inode that
551 * will be used if this dentry were opened as a file. It may be the upper
552 * dentry or it may be a lower dentry pinned by the upper.
553 *
554 * Normal filesystems should not use this to access their own dentries.
555 */
556static inline struct dentry *d_backing_dentry(struct dentry *upper)
557{
558 return upper;
559}
560
Miklos Szeredie698b8a2016-06-30 08:53:27 +0200561/**
562 * d_real - Return the real dentry
563 * @dentry: the dentry to query
564 * @inode: inode to select the dentry from multiple layers (can be NULL)
565 * @flags: open flags to control copy-up behavior
566 *
567 * If dentry is on an union/overlay, then return the underlying, real dentry.
568 * Otherwise return the dentry itself.
569 *
570 * See also: Documentation/filesystems/vfs.txt
571 */
Miklos Szeredi2d902672016-06-30 08:53:27 +0200572static inline struct dentry *d_real(struct dentry *dentry,
573 const struct inode *inode,
574 unsigned int flags)
Miklos Szeredid101a122016-03-26 16:14:37 -0400575{
576 if (unlikely(dentry->d_flags & DCACHE_OP_REAL))
Miklos Szeredi2d902672016-06-30 08:53:27 +0200577 return dentry->d_op->d_real(dentry, inode, flags);
Miklos Szeredid101a122016-03-26 16:14:37 -0400578 else
579 return dentry;
580}
581
Miklos Szeredia11808442016-05-20 22:13:45 +0200582/**
583 * d_real_inode - Return the real inode
584 * @dentry: The dentry to query
585 *
586 * If dentry is on an union/overlay, then return the underlying, real inode.
587 * Otherwise return d_inode().
588 */
Miklos Szeredi7b1742e2016-09-16 12:44:20 +0200589static inline struct inode *d_real_inode(const struct dentry *dentry)
Miklos Szeredia11808442016-05-20 22:13:45 +0200590{
Miklos Szeredi7b1742e2016-09-16 12:44:20 +0200591 /* This usage of d_real() results in const dentry */
592 return d_backing_inode(d_real((struct dentry *) dentry, NULL, 0));
Miklos Szeredia11808442016-05-20 22:13:45 +0200593}
594
Al Viroad25f112017-07-07 14:51:19 -0400595struct name_snapshot {
596 const char *name;
597 char inline_name[DNAME_INLINE_LEN];
598};
599void take_dentry_name_snapshot(struct name_snapshot *, struct dentry *);
600void release_dentry_name_snapshot(struct name_snapshot *);
Miklos Szeredi54d5ca82016-05-11 01:16:37 +0200601
Linus Torvalds1da177e2005-04-16 15:20:36 -0700602#endif /* __LINUX_DCACHE_H */