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c088e31d SF |
1 | /* |
2 | * Copyright (C) 2005-2017 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 | #include "aufs.h" | |
23 | ||
24 | static void au_dpage_free(struct au_dpage *dpage) | |
25 | { | |
26 | int i; | |
27 | struct dentry **p; | |
28 | ||
29 | p = dpage->dentries; | |
30 | for (i = 0; i < dpage->ndentry; i++) | |
31 | dput(*p++); | |
32 | free_page((unsigned long)dpage->dentries); | |
33 | } | |
34 | ||
35 | int au_dpages_init(struct au_dcsub_pages *dpages, gfp_t gfp) | |
36 | { | |
37 | int err; | |
38 | void *p; | |
39 | ||
40 | err = -ENOMEM; | |
41 | dpages->dpages = kmalloc(sizeof(*dpages->dpages), gfp); | |
42 | if (unlikely(!dpages->dpages)) | |
43 | goto out; | |
44 | ||
45 | p = (void *)__get_free_page(gfp); | |
46 | if (unlikely(!p)) | |
47 | goto out_dpages; | |
48 | ||
49 | dpages->dpages[0].ndentry = 0; | |
50 | dpages->dpages[0].dentries = p; | |
51 | dpages->ndpage = 1; | |
52 | return 0; /* success */ | |
53 | ||
54 | out_dpages: | |
55 | kfree(dpages->dpages); | |
56 | out: | |
57 | return err; | |
58 | } | |
59 | ||
60 | void au_dpages_free(struct au_dcsub_pages *dpages) | |
61 | { | |
62 | int i; | |
63 | struct au_dpage *p; | |
64 | ||
65 | p = dpages->dpages; | |
66 | for (i = 0; i < dpages->ndpage; i++) | |
67 | au_dpage_free(p++); | |
68 | kfree(dpages->dpages); | |
69 | } | |
70 | ||
71 | static int au_dpages_append(struct au_dcsub_pages *dpages, | |
72 | struct dentry *dentry, gfp_t gfp) | |
73 | { | |
74 | int err, sz; | |
75 | struct au_dpage *dpage; | |
76 | void *p; | |
77 | ||
78 | dpage = dpages->dpages + dpages->ndpage - 1; | |
79 | sz = PAGE_SIZE / sizeof(dentry); | |
80 | if (unlikely(dpage->ndentry >= sz)) { | |
81 | AuLabel(new dpage); | |
82 | err = -ENOMEM; | |
83 | sz = dpages->ndpage * sizeof(*dpages->dpages); | |
84 | p = au_kzrealloc(dpages->dpages, sz, | |
85 | sz + sizeof(*dpages->dpages), gfp, | |
86 | /*may_shrink*/0); | |
87 | if (unlikely(!p)) | |
88 | goto out; | |
89 | ||
90 | dpages->dpages = p; | |
91 | dpage = dpages->dpages + dpages->ndpage; | |
92 | p = (void *)__get_free_page(gfp); | |
93 | if (unlikely(!p)) | |
94 | goto out; | |
95 | ||
96 | dpage->ndentry = 0; | |
97 | dpage->dentries = p; | |
98 | dpages->ndpage++; | |
99 | } | |
100 | ||
101 | AuDebugOn(au_dcount(dentry) <= 0); | |
102 | dpage->dentries[dpage->ndentry++] = dget_dlock(dentry); | |
103 | return 0; /* success */ | |
104 | ||
105 | out: | |
106 | return err; | |
107 | } | |
108 | ||
109 | /* todo: BAD approach */ | |
110 | /* copied from linux/fs/dcache.c */ | |
111 | enum d_walk_ret { | |
112 | D_WALK_CONTINUE, | |
113 | D_WALK_QUIT, | |
114 | D_WALK_NORETRY, | |
115 | D_WALK_SKIP, | |
116 | }; | |
117 | ||
118 | extern void d_walk(struct dentry *parent, void *data, | |
119 | enum d_walk_ret (*enter)(void *, struct dentry *), | |
120 | void (*finish)(void *)); | |
121 | ||
122 | struct ac_dpages_arg { | |
123 | int err; | |
124 | struct au_dcsub_pages *dpages; | |
125 | struct super_block *sb; | |
126 | au_dpages_test test; | |
127 | void *arg; | |
128 | }; | |
129 | ||
130 | static enum d_walk_ret au_call_dpages_append(void *_arg, struct dentry *dentry) | |
131 | { | |
132 | enum d_walk_ret ret; | |
133 | struct ac_dpages_arg *arg = _arg; | |
134 | ||
135 | ret = D_WALK_CONTINUE; | |
136 | if (dentry->d_sb == arg->sb | |
137 | && !IS_ROOT(dentry) | |
138 | && au_dcount(dentry) > 0 | |
139 | && au_di(dentry) | |
140 | && (!arg->test || arg->test(dentry, arg->arg))) { | |
141 | arg->err = au_dpages_append(arg->dpages, dentry, GFP_ATOMIC); | |
142 | if (unlikely(arg->err)) | |
143 | ret = D_WALK_QUIT; | |
144 | } | |
145 | ||
146 | return ret; | |
147 | } | |
148 | ||
149 | int au_dcsub_pages(struct au_dcsub_pages *dpages, struct dentry *root, | |
150 | au_dpages_test test, void *arg) | |
151 | { | |
152 | struct ac_dpages_arg args = { | |
153 | .err = 0, | |
154 | .dpages = dpages, | |
155 | .sb = root->d_sb, | |
156 | .test = test, | |
157 | .arg = arg | |
158 | }; | |
159 | ||
160 | d_walk(root, &args, au_call_dpages_append, NULL); | |
161 | ||
162 | return args.err; | |
163 | } | |
164 | ||
165 | int au_dcsub_pages_rev(struct au_dcsub_pages *dpages, struct dentry *dentry, | |
166 | int do_include, au_dpages_test test, void *arg) | |
167 | { | |
168 | int err; | |
169 | ||
170 | err = 0; | |
171 | write_seqlock(&rename_lock); | |
172 | spin_lock(&dentry->d_lock); | |
173 | if (do_include | |
174 | && au_dcount(dentry) > 0 | |
175 | && (!test || test(dentry, arg))) | |
176 | err = au_dpages_append(dpages, dentry, GFP_ATOMIC); | |
177 | spin_unlock(&dentry->d_lock); | |
178 | if (unlikely(err)) | |
179 | goto out; | |
180 | ||
181 | /* | |
182 | * RCU for vfsmount is unnecessary since this is a traverse in a single | |
183 | * mount | |
184 | */ | |
185 | while (!IS_ROOT(dentry)) { | |
186 | dentry = dentry->d_parent; /* rename_lock is locked */ | |
187 | spin_lock(&dentry->d_lock); | |
188 | if (au_dcount(dentry) > 0 | |
189 | && (!test || test(dentry, arg))) | |
190 | err = au_dpages_append(dpages, dentry, GFP_ATOMIC); | |
191 | spin_unlock(&dentry->d_lock); | |
192 | if (unlikely(err)) | |
193 | break; | |
194 | } | |
195 | ||
196 | out: | |
197 | write_sequnlock(&rename_lock); | |
198 | return err; | |
199 | } | |
200 | ||
201 | static inline int au_dcsub_dpages_aufs(struct dentry *dentry, void *arg) | |
202 | { | |
203 | return au_di(dentry) && dentry->d_sb == arg; | |
204 | } | |
205 | ||
206 | int au_dcsub_pages_rev_aufs(struct au_dcsub_pages *dpages, | |
207 | struct dentry *dentry, int do_include) | |
208 | { | |
209 | return au_dcsub_pages_rev(dpages, dentry, do_include, | |
210 | au_dcsub_dpages_aufs, dentry->d_sb); | |
211 | } | |
212 | ||
213 | int au_test_subdir(struct dentry *d1, struct dentry *d2) | |
214 | { | |
215 | struct path path[2] = { | |
216 | { | |
217 | .dentry = d1 | |
218 | }, | |
219 | { | |
220 | .dentry = d2 | |
221 | } | |
222 | }; | |
223 | ||
224 | return path_is_under(path + 0, path + 1); | |
225 | } |