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bbb1e54d MS |
1 | /* |
2 | * Copyright (C) 2011 Novell Inc. | |
3 | * Copyright (C) 2016 Red Hat, Inc. | |
4 | * | |
5 | * This program is free software; you can redistribute it and/or modify it | |
6 | * under the terms of the GNU General Public License version 2 as published by | |
7 | * the Free Software Foundation. | |
8 | */ | |
9 | ||
10 | #include <linux/fs.h> | |
11 | #include <linux/mount.h> | |
12 | #include <linux/slab.h> | |
5b825c3a | 13 | #include <linux/cred.h> |
bbb1e54d MS |
14 | #include <linux/xattr.h> |
15 | #include "overlayfs.h" | |
16 | #include "ovl_entry.h" | |
17 | ||
18 | int ovl_want_write(struct dentry *dentry) | |
19 | { | |
20 | struct ovl_fs *ofs = dentry->d_sb->s_fs_info; | |
21 | return mnt_want_write(ofs->upper_mnt); | |
22 | } | |
23 | ||
24 | void ovl_drop_write(struct dentry *dentry) | |
25 | { | |
26 | struct ovl_fs *ofs = dentry->d_sb->s_fs_info; | |
27 | mnt_drop_write(ofs->upper_mnt); | |
28 | } | |
29 | ||
30 | struct dentry *ovl_workdir(struct dentry *dentry) | |
31 | { | |
32 | struct ovl_fs *ofs = dentry->d_sb->s_fs_info; | |
33 | return ofs->workdir; | |
34 | } | |
35 | ||
36 | const struct cred *ovl_override_creds(struct super_block *sb) | |
37 | { | |
38 | struct ovl_fs *ofs = sb->s_fs_info; | |
39 | ||
40 | return override_creds(ofs->creator_cred); | |
41 | } | |
42 | ||
43 | struct ovl_entry *ovl_alloc_entry(unsigned int numlower) | |
44 | { | |
45 | size_t size = offsetof(struct ovl_entry, lowerstack[numlower]); | |
46 | struct ovl_entry *oe = kzalloc(size, GFP_KERNEL); | |
47 | ||
48 | if (oe) | |
49 | oe->numlower = numlower; | |
50 | ||
51 | return oe; | |
52 | } | |
53 | ||
54 | bool ovl_dentry_remote(struct dentry *dentry) | |
55 | { | |
56 | return dentry->d_flags & | |
57 | (DCACHE_OP_REVALIDATE | DCACHE_OP_WEAK_REVALIDATE | | |
58 | DCACHE_OP_REAL); | |
59 | } | |
60 | ||
61 | bool ovl_dentry_weird(struct dentry *dentry) | |
62 | { | |
63 | return dentry->d_flags & (DCACHE_NEED_AUTOMOUNT | | |
64 | DCACHE_MANAGE_TRANSIT | | |
65 | DCACHE_OP_HASH | | |
66 | DCACHE_OP_COMPARE); | |
67 | } | |
68 | ||
69 | enum ovl_path_type ovl_path_type(struct dentry *dentry) | |
70 | { | |
71 | struct ovl_entry *oe = dentry->d_fsdata; | |
72 | enum ovl_path_type type = 0; | |
73 | ||
74 | if (oe->__upperdentry) { | |
75 | type = __OVL_PATH_UPPER; | |
76 | ||
77 | /* | |
78 | * Non-dir dentry can hold lower dentry from previous | |
79 | * location. | |
80 | */ | |
81 | if (oe->numlower && d_is_dir(dentry)) | |
82 | type |= __OVL_PATH_MERGE; | |
83 | } else { | |
84 | if (oe->numlower > 1) | |
85 | type |= __OVL_PATH_MERGE; | |
86 | } | |
87 | return type; | |
88 | } | |
89 | ||
90 | void ovl_path_upper(struct dentry *dentry, struct path *path) | |
91 | { | |
92 | struct ovl_fs *ofs = dentry->d_sb->s_fs_info; | |
93 | struct ovl_entry *oe = dentry->d_fsdata; | |
94 | ||
95 | path->mnt = ofs->upper_mnt; | |
96 | path->dentry = ovl_upperdentry_dereference(oe); | |
97 | } | |
98 | ||
99 | void ovl_path_lower(struct dentry *dentry, struct path *path) | |
100 | { | |
101 | struct ovl_entry *oe = dentry->d_fsdata; | |
102 | ||
103 | *path = oe->numlower ? oe->lowerstack[0] : (struct path) { NULL, NULL }; | |
104 | } | |
105 | ||
106 | enum ovl_path_type ovl_path_real(struct dentry *dentry, struct path *path) | |
107 | { | |
108 | enum ovl_path_type type = ovl_path_type(dentry); | |
109 | ||
110 | if (!OVL_TYPE_UPPER(type)) | |
111 | ovl_path_lower(dentry, path); | |
112 | else | |
113 | ovl_path_upper(dentry, path); | |
114 | ||
115 | return type; | |
116 | } | |
117 | ||
118 | struct dentry *ovl_dentry_upper(struct dentry *dentry) | |
119 | { | |
120 | struct ovl_entry *oe = dentry->d_fsdata; | |
121 | ||
122 | return ovl_upperdentry_dereference(oe); | |
123 | } | |
124 | ||
125 | static struct dentry *__ovl_dentry_lower(struct ovl_entry *oe) | |
126 | { | |
127 | return oe->numlower ? oe->lowerstack[0].dentry : NULL; | |
128 | } | |
129 | ||
130 | struct dentry *ovl_dentry_lower(struct dentry *dentry) | |
131 | { | |
132 | struct ovl_entry *oe = dentry->d_fsdata; | |
133 | ||
134 | return __ovl_dentry_lower(oe); | |
135 | } | |
136 | ||
137 | struct dentry *ovl_dentry_real(struct dentry *dentry) | |
138 | { | |
139 | struct ovl_entry *oe = dentry->d_fsdata; | |
140 | struct dentry *realdentry; | |
141 | ||
142 | realdentry = ovl_upperdentry_dereference(oe); | |
143 | if (!realdentry) | |
144 | realdentry = __ovl_dentry_lower(oe); | |
145 | ||
146 | return realdentry; | |
147 | } | |
148 | ||
149 | struct ovl_dir_cache *ovl_dir_cache(struct dentry *dentry) | |
150 | { | |
151 | struct ovl_entry *oe = dentry->d_fsdata; | |
152 | ||
153 | return oe->cache; | |
154 | } | |
155 | ||
156 | void ovl_set_dir_cache(struct dentry *dentry, struct ovl_dir_cache *cache) | |
157 | { | |
158 | struct ovl_entry *oe = dentry->d_fsdata; | |
159 | ||
160 | oe->cache = cache; | |
161 | } | |
162 | ||
163 | bool ovl_dentry_is_opaque(struct dentry *dentry) | |
164 | { | |
165 | struct ovl_entry *oe = dentry->d_fsdata; | |
166 | return oe->opaque; | |
167 | } | |
168 | ||
169 | bool ovl_dentry_is_whiteout(struct dentry *dentry) | |
170 | { | |
171 | return !dentry->d_inode && ovl_dentry_is_opaque(dentry); | |
172 | } | |
173 | ||
5cf5b477 | 174 | void ovl_dentry_set_opaque(struct dentry *dentry) |
bbb1e54d MS |
175 | { |
176 | struct ovl_entry *oe = dentry->d_fsdata; | |
5cf5b477 MS |
177 | |
178 | oe->opaque = true; | |
bbb1e54d MS |
179 | } |
180 | ||
a6c60655 MS |
181 | bool ovl_redirect_dir(struct super_block *sb) |
182 | { | |
183 | struct ovl_fs *ofs = sb->s_fs_info; | |
184 | ||
185 | return ofs->config.redirect_dir; | |
186 | } | |
187 | ||
188 | void ovl_clear_redirect_dir(struct super_block *sb) | |
189 | { | |
190 | struct ovl_fs *ofs = sb->s_fs_info; | |
191 | ||
192 | ofs->config.redirect_dir = false; | |
193 | } | |
194 | ||
195 | const char *ovl_dentry_get_redirect(struct dentry *dentry) | |
196 | { | |
197 | struct ovl_entry *oe = dentry->d_fsdata; | |
198 | ||
199 | return oe->redirect; | |
200 | } | |
201 | ||
202 | void ovl_dentry_set_redirect(struct dentry *dentry, const char *redirect) | |
203 | { | |
204 | struct ovl_entry *oe = dentry->d_fsdata; | |
205 | ||
206 | kfree(oe->redirect); | |
207 | oe->redirect = redirect; | |
208 | } | |
209 | ||
bbb1e54d MS |
210 | void ovl_dentry_update(struct dentry *dentry, struct dentry *upperdentry) |
211 | { | |
212 | struct ovl_entry *oe = dentry->d_fsdata; | |
213 | ||
214 | WARN_ON(!inode_is_locked(upperdentry->d_parent->d_inode)); | |
215 | WARN_ON(oe->__upperdentry); | |
216 | /* | |
217 | * Make sure upperdentry is consistent before making it visible to | |
218 | * ovl_upperdentry_dereference(). | |
219 | */ | |
220 | smp_wmb(); | |
221 | oe->__upperdentry = upperdentry; | |
222 | } | |
223 | ||
224 | void ovl_inode_init(struct inode *inode, struct inode *realinode, bool is_upper) | |
225 | { | |
226 | WRITE_ONCE(inode->i_private, (unsigned long) realinode | | |
227 | (is_upper ? OVL_ISUPPER_MASK : 0)); | |
228 | } | |
229 | ||
230 | void ovl_inode_update(struct inode *inode, struct inode *upperinode) | |
231 | { | |
232 | WARN_ON(!upperinode); | |
233 | WARN_ON(!inode_unhashed(inode)); | |
234 | WRITE_ONCE(inode->i_private, | |
235 | (unsigned long) upperinode | OVL_ISUPPER_MASK); | |
236 | if (!S_ISDIR(upperinode->i_mode)) | |
237 | __insert_inode_hash(inode, (unsigned long) upperinode); | |
238 | } | |
239 | ||
240 | void ovl_dentry_version_inc(struct dentry *dentry) | |
241 | { | |
242 | struct ovl_entry *oe = dentry->d_fsdata; | |
243 | ||
244 | WARN_ON(!inode_is_locked(dentry->d_inode)); | |
245 | oe->version++; | |
246 | } | |
247 | ||
248 | u64 ovl_dentry_version_get(struct dentry *dentry) | |
249 | { | |
250 | struct ovl_entry *oe = dentry->d_fsdata; | |
251 | ||
252 | WARN_ON(!inode_is_locked(dentry->d_inode)); | |
253 | return oe->version; | |
254 | } | |
255 | ||
256 | bool ovl_is_whiteout(struct dentry *dentry) | |
257 | { | |
258 | struct inode *inode = dentry->d_inode; | |
259 | ||
260 | return inode && IS_WHITEOUT(inode); | |
261 | } | |
262 | ||
263 | struct file *ovl_path_open(struct path *path, int flags) | |
264 | { | |
265 | return dentry_open(path, flags | O_NOATIME, current_cred()); | |
266 | } | |
39d3d60a AG |
267 | |
268 | int ovl_copy_up_start(struct dentry *dentry) | |
269 | { | |
270 | struct ovl_fs *ofs = dentry->d_sb->s_fs_info; | |
271 | struct ovl_entry *oe = dentry->d_fsdata; | |
272 | int err; | |
273 | ||
274 | spin_lock(&ofs->copyup_wq.lock); | |
275 | err = wait_event_interruptible_locked(ofs->copyup_wq, !oe->copying); | |
276 | if (!err) { | |
277 | if (oe->__upperdentry) | |
278 | err = 1; /* Already copied up */ | |
279 | else | |
280 | oe->copying = true; | |
281 | } | |
282 | spin_unlock(&ofs->copyup_wq.lock); | |
283 | ||
284 | return err; | |
285 | } | |
286 | ||
287 | void ovl_copy_up_end(struct dentry *dentry) | |
288 | { | |
289 | struct ovl_fs *ofs = dentry->d_sb->s_fs_info; | |
290 | struct ovl_entry *oe = dentry->d_fsdata; | |
291 | ||
292 | spin_lock(&ofs->copyup_wq.lock); | |
293 | oe->copying = false; | |
294 | wake_up_locked(&ofs->copyup_wq); | |
295 | spin_unlock(&ofs->copyup_wq.lock); | |
296 | } |