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e14748e8 SF |
1 | /* |
2 | * Copyright (C) 2005-2016 Junjiro R. Okajima | |
3 | * | |
4 | * This program, aufs is free software; you can redistribute it and/or modify | |
5 | * it under the terms of the GNU General Public License as published by | |
6 | * the Free Software Foundation; either version 2 of the License, or | |
7 | * (at your option) any later version. | |
8 | * | |
9 | * This program is distributed in the hope that it will be useful, | |
10 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
11 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
12 | * GNU General Public License for more details. | |
13 | * | |
14 | * You should have received a copy of the GNU General Public License | |
15 | * along with this program. If not, see <http://www.gnu.org/licenses/>. | |
16 | */ | |
17 | ||
18 | /* | |
19 | * sub-routines for dentry cache | |
20 | */ | |
21 | ||
22 | #ifndef __AUFS_DCSUB_H__ | |
23 | #define __AUFS_DCSUB_H__ | |
24 | ||
25 | #ifdef __KERNEL__ | |
26 | ||
27 | #include <linux/dcache.h> | |
28 | #include <linux/fs.h> | |
29 | ||
30 | struct au_dpage { | |
31 | int ndentry; | |
32 | struct dentry **dentries; | |
33 | }; | |
34 | ||
35 | struct au_dcsub_pages { | |
36 | int ndpage; | |
37 | struct au_dpage *dpages; | |
38 | }; | |
39 | ||
40 | /* ---------------------------------------------------------------------- */ | |
41 | ||
42 | /* dcsub.c */ | |
43 | int au_dpages_init(struct au_dcsub_pages *dpages, gfp_t gfp); | |
44 | void au_dpages_free(struct au_dcsub_pages *dpages); | |
45 | typedef int (*au_dpages_test)(struct dentry *dentry, void *arg); | |
46 | int au_dcsub_pages(struct au_dcsub_pages *dpages, struct dentry *root, | |
47 | au_dpages_test test, void *arg); | |
48 | int au_dcsub_pages_rev(struct au_dcsub_pages *dpages, struct dentry *dentry, | |
49 | int do_include, au_dpages_test test, void *arg); | |
50 | int au_dcsub_pages_rev_aufs(struct au_dcsub_pages *dpages, | |
51 | struct dentry *dentry, int do_include); | |
52 | int au_test_subdir(struct dentry *d1, struct dentry *d2); | |
53 | ||
54 | /* ---------------------------------------------------------------------- */ | |
55 | ||
56 | /* | |
57 | * todo: in linux-3.13, several similar (but faster) helpers are added to | |
58 | * include/linux/dcache.h. Try them (in the future). | |
59 | */ | |
60 | ||
61 | static inline int au_d_hashed_positive(struct dentry *d) | |
62 | { | |
63 | int err; | |
64 | struct inode *inode = d_inode(d); | |
65 | ||
66 | err = 0; | |
67 | if (unlikely(d_unhashed(d) | |
68 | || d_is_negative(d) | |
69 | || !inode->i_nlink)) | |
70 | err = -ENOENT; | |
71 | return err; | |
72 | } | |
73 | ||
74 | static inline int au_d_linkable(struct dentry *d) | |
75 | { | |
76 | int err; | |
77 | struct inode *inode = d_inode(d); | |
78 | ||
79 | err = au_d_hashed_positive(d); | |
80 | if (err | |
81 | && d_is_positive(d) | |
82 | && (inode->i_state & I_LINKABLE)) | |
83 | err = 0; | |
84 | return err; | |
85 | } | |
86 | ||
87 | static inline int au_d_alive(struct dentry *d) | |
88 | { | |
89 | int err; | |
90 | struct inode *inode; | |
91 | ||
92 | err = 0; | |
93 | if (!IS_ROOT(d)) | |
94 | err = au_d_hashed_positive(d); | |
95 | else { | |
96 | inode = d_inode(d); | |
97 | if (unlikely(d_unlinked(d) | |
98 | || d_is_negative(d) | |
99 | || !inode->i_nlink)) | |
100 | err = -ENOENT; | |
101 | } | |
102 | return err; | |
103 | } | |
104 | ||
105 | static inline int au_alive_dir(struct dentry *d) | |
106 | { | |
107 | int err; | |
108 | ||
109 | err = au_d_alive(d); | |
110 | if (unlikely(err || IS_DEADDIR(d_inode(d)))) | |
111 | err = -ENOENT; | |
112 | return err; | |
113 | } | |
114 | ||
115 | static inline int au_qstreq(struct qstr *a, struct qstr *b) | |
116 | { | |
117 | return a->len == b->len | |
118 | && !memcmp(a->name, b->name, a->len); | |
119 | } | |
120 | ||
121 | /* | |
122 | * by the commit | |
123 | * 360f547 2015-01-25 dcache: let the dentry count go down to zero without | |
124 | * taking d_lock | |
125 | * the type of d_lockref.count became int, but the inlined function d_count() | |
126 | * still returns unsigned int. | |
127 | * I don't know why. Maybe it is for every d_count() users? | |
128 | * Anyway au_dcount() lives on. | |
129 | */ | |
130 | static inline int au_dcount(struct dentry *d) | |
131 | { | |
132 | return (int)d_count(d); | |
133 | } | |
134 | ||
135 | #endif /* __KERNEL__ */ | |
136 | #endif /* __AUFS_DCSUB_H__ */ |