Commit | Line | Data |
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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 | 14 | #include <linux/xattr.h> |
02bcd157 AG |
15 | #include <linux/exportfs.h> |
16 | #include <linux/uuid.h> | |
bbb1e54d MS |
17 | #include "overlayfs.h" |
18 | #include "ovl_entry.h" | |
19 | ||
20 | int ovl_want_write(struct dentry *dentry) | |
21 | { | |
22 | struct ovl_fs *ofs = dentry->d_sb->s_fs_info; | |
23 | return mnt_want_write(ofs->upper_mnt); | |
24 | } | |
25 | ||
26 | void ovl_drop_write(struct dentry *dentry) | |
27 | { | |
28 | struct ovl_fs *ofs = dentry->d_sb->s_fs_info; | |
29 | mnt_drop_write(ofs->upper_mnt); | |
30 | } | |
31 | ||
32 | struct dentry *ovl_workdir(struct dentry *dentry) | |
33 | { | |
34 | struct ovl_fs *ofs = dentry->d_sb->s_fs_info; | |
35 | return ofs->workdir; | |
36 | } | |
37 | ||
38 | const struct cred *ovl_override_creds(struct super_block *sb) | |
39 | { | |
40 | struct ovl_fs *ofs = sb->s_fs_info; | |
41 | ||
42 | return override_creds(ofs->creator_cred); | |
43 | } | |
44 | ||
7bcd74b9 AG |
45 | struct super_block *ovl_same_sb(struct super_block *sb) |
46 | { | |
47 | struct ovl_fs *ofs = sb->s_fs_info; | |
48 | ||
49 | return ofs->same_sb; | |
50 | } | |
51 | ||
02bcd157 AG |
52 | bool ovl_can_decode_fh(struct super_block *sb) |
53 | { | |
54 | return (sb->s_export_op && sb->s_export_op->fh_to_dentry && | |
55 | !uuid_is_null(&sb->s_uuid)); | |
56 | } | |
57 | ||
58 | struct dentry *ovl_indexdir(struct super_block *sb) | |
59 | { | |
60 | struct ovl_fs *ofs = sb->s_fs_info; | |
61 | ||
62 | return ofs->indexdir; | |
63 | } | |
64 | ||
bbb1e54d MS |
65 | struct ovl_entry *ovl_alloc_entry(unsigned int numlower) |
66 | { | |
67 | size_t size = offsetof(struct ovl_entry, lowerstack[numlower]); | |
68 | struct ovl_entry *oe = kzalloc(size, GFP_KERNEL); | |
69 | ||
70 | if (oe) | |
71 | oe->numlower = numlower; | |
72 | ||
73 | return oe; | |
74 | } | |
75 | ||
76 | bool ovl_dentry_remote(struct dentry *dentry) | |
77 | { | |
78 | return dentry->d_flags & | |
79 | (DCACHE_OP_REVALIDATE | DCACHE_OP_WEAK_REVALIDATE | | |
80 | DCACHE_OP_REAL); | |
81 | } | |
82 | ||
83 | bool ovl_dentry_weird(struct dentry *dentry) | |
84 | { | |
85 | return dentry->d_flags & (DCACHE_NEED_AUTOMOUNT | | |
86 | DCACHE_MANAGE_TRANSIT | | |
87 | DCACHE_OP_HASH | | |
88 | DCACHE_OP_COMPARE); | |
89 | } | |
90 | ||
91 | enum ovl_path_type ovl_path_type(struct dentry *dentry) | |
92 | { | |
93 | struct ovl_entry *oe = dentry->d_fsdata; | |
94 | enum ovl_path_type type = 0; | |
95 | ||
09d8b586 | 96 | if (ovl_dentry_upper(dentry)) { |
bbb1e54d MS |
97 | type = __OVL_PATH_UPPER; |
98 | ||
99 | /* | |
59548503 | 100 | * Non-dir dentry can hold lower dentry of its copy up origin. |
bbb1e54d | 101 | */ |
59548503 AG |
102 | if (oe->numlower) { |
103 | type |= __OVL_PATH_ORIGIN; | |
104 | if (d_is_dir(dentry)) | |
105 | type |= __OVL_PATH_MERGE; | |
106 | } | |
bbb1e54d MS |
107 | } else { |
108 | if (oe->numlower > 1) | |
109 | type |= __OVL_PATH_MERGE; | |
110 | } | |
111 | return type; | |
112 | } | |
113 | ||
114 | void ovl_path_upper(struct dentry *dentry, struct path *path) | |
115 | { | |
116 | struct ovl_fs *ofs = dentry->d_sb->s_fs_info; | |
bbb1e54d MS |
117 | |
118 | path->mnt = ofs->upper_mnt; | |
09d8b586 | 119 | path->dentry = ovl_dentry_upper(dentry); |
bbb1e54d MS |
120 | } |
121 | ||
122 | void ovl_path_lower(struct dentry *dentry, struct path *path) | |
123 | { | |
124 | struct ovl_entry *oe = dentry->d_fsdata; | |
125 | ||
33006cdf | 126 | *path = oe->numlower ? oe->lowerstack[0] : (struct path) { }; |
bbb1e54d MS |
127 | } |
128 | ||
129 | enum ovl_path_type ovl_path_real(struct dentry *dentry, struct path *path) | |
130 | { | |
131 | enum ovl_path_type type = ovl_path_type(dentry); | |
132 | ||
133 | if (!OVL_TYPE_UPPER(type)) | |
134 | ovl_path_lower(dentry, path); | |
135 | else | |
136 | ovl_path_upper(dentry, path); | |
137 | ||
138 | return type; | |
139 | } | |
140 | ||
141 | struct dentry *ovl_dentry_upper(struct dentry *dentry) | |
142 | { | |
09d8b586 | 143 | return ovl_upperdentry_dereference(OVL_I(d_inode(dentry))); |
bbb1e54d MS |
144 | } |
145 | ||
146 | struct dentry *ovl_dentry_lower(struct dentry *dentry) | |
147 | { | |
148 | struct ovl_entry *oe = dentry->d_fsdata; | |
149 | ||
09d8b586 | 150 | return oe->numlower ? oe->lowerstack[0].dentry : NULL; |
bbb1e54d MS |
151 | } |
152 | ||
153 | struct dentry *ovl_dentry_real(struct dentry *dentry) | |
154 | { | |
09d8b586 | 155 | return ovl_dentry_upper(dentry) ?: ovl_dentry_lower(dentry); |
bbb1e54d MS |
156 | } |
157 | ||
09d8b586 | 158 | struct inode *ovl_inode_upper(struct inode *inode) |
25b7713a | 159 | { |
09d8b586 | 160 | struct dentry *upperdentry = ovl_upperdentry_dereference(OVL_I(inode)); |
25b7713a | 161 | |
09d8b586 MS |
162 | return upperdentry ? d_inode(upperdentry) : NULL; |
163 | } | |
25b7713a | 164 | |
09d8b586 MS |
165 | struct inode *ovl_inode_lower(struct inode *inode) |
166 | { | |
167 | return OVL_I(inode)->lower; | |
168 | } | |
25b7713a | 169 | |
09d8b586 MS |
170 | struct inode *ovl_inode_real(struct inode *inode) |
171 | { | |
172 | return ovl_inode_upper(inode) ?: ovl_inode_lower(inode); | |
25b7713a MS |
173 | } |
174 | ||
09d8b586 | 175 | |
bbb1e54d MS |
176 | struct ovl_dir_cache *ovl_dir_cache(struct dentry *dentry) |
177 | { | |
04a01ac7 | 178 | return OVL_I(d_inode(dentry))->cache; |
bbb1e54d MS |
179 | } |
180 | ||
181 | void ovl_set_dir_cache(struct dentry *dentry, struct ovl_dir_cache *cache) | |
182 | { | |
04a01ac7 | 183 | OVL_I(d_inode(dentry))->cache = cache; |
bbb1e54d MS |
184 | } |
185 | ||
186 | bool ovl_dentry_is_opaque(struct dentry *dentry) | |
187 | { | |
188 | struct ovl_entry *oe = dentry->d_fsdata; | |
189 | return oe->opaque; | |
190 | } | |
191 | ||
192 | bool ovl_dentry_is_whiteout(struct dentry *dentry) | |
193 | { | |
194 | return !dentry->d_inode && ovl_dentry_is_opaque(dentry); | |
195 | } | |
196 | ||
5cf5b477 | 197 | void ovl_dentry_set_opaque(struct dentry *dentry) |
bbb1e54d MS |
198 | { |
199 | struct ovl_entry *oe = dentry->d_fsdata; | |
5cf5b477 MS |
200 | |
201 | oe->opaque = true; | |
bbb1e54d MS |
202 | } |
203 | ||
55acc661 MS |
204 | /* |
205 | * For hard links it's possible for ovl_dentry_upper() to return positive, while | |
206 | * there's no actual upper alias for the inode. Copy up code needs to know | |
207 | * about the existence of the upper alias, so it can't use ovl_dentry_upper(). | |
208 | */ | |
209 | bool ovl_dentry_has_upper_alias(struct dentry *dentry) | |
210 | { | |
211 | struct ovl_entry *oe = dentry->d_fsdata; | |
212 | ||
213 | return oe->has_upper; | |
214 | } | |
215 | ||
216 | void ovl_dentry_set_upper_alias(struct dentry *dentry) | |
217 | { | |
218 | struct ovl_entry *oe = dentry->d_fsdata; | |
219 | ||
220 | oe->has_upper = true; | |
221 | } | |
222 | ||
a6c60655 MS |
223 | bool ovl_redirect_dir(struct super_block *sb) |
224 | { | |
225 | struct ovl_fs *ofs = sb->s_fs_info; | |
226 | ||
21a22878 | 227 | return ofs->config.redirect_dir && !ofs->noxattr; |
a6c60655 MS |
228 | } |
229 | ||
230 | const char *ovl_dentry_get_redirect(struct dentry *dentry) | |
231 | { | |
cf31c463 | 232 | return OVL_I(d_inode(dentry))->redirect; |
a6c60655 MS |
233 | } |
234 | ||
235 | void ovl_dentry_set_redirect(struct dentry *dentry, const char *redirect) | |
236 | { | |
cf31c463 | 237 | struct ovl_inode *oi = OVL_I(d_inode(dentry)); |
a6c60655 | 238 | |
cf31c463 MS |
239 | kfree(oi->redirect); |
240 | oi->redirect = redirect; | |
a6c60655 MS |
241 | } |
242 | ||
09d8b586 MS |
243 | void ovl_inode_init(struct inode *inode, struct dentry *upperdentry, |
244 | struct dentry *lowerdentry) | |
bbb1e54d | 245 | { |
09d8b586 MS |
246 | if (upperdentry) |
247 | OVL_I(inode)->__upperdentry = upperdentry; | |
248 | if (lowerdentry) | |
249 | OVL_I(inode)->lower = d_inode(lowerdentry); | |
bbb1e54d | 250 | |
09d8b586 | 251 | ovl_copyattr(d_inode(upperdentry ?: lowerdentry), inode); |
bbb1e54d MS |
252 | } |
253 | ||
09d8b586 | 254 | void ovl_inode_update(struct inode *inode, struct dentry *upperdentry) |
bbb1e54d | 255 | { |
09d8b586 | 256 | struct inode *upperinode = d_inode(upperdentry); |
e6d2ebdd | 257 | |
09d8b586 MS |
258 | WARN_ON(OVL_I(inode)->__upperdentry); |
259 | ||
25b7713a | 260 | /* |
09d8b586 | 261 | * Make sure upperdentry is consistent before making it visible |
25b7713a MS |
262 | */ |
263 | smp_wmb(); | |
09d8b586 | 264 | OVL_I(inode)->__upperdentry = upperdentry; |
b9ac5c27 | 265 | if (!S_ISDIR(upperinode->i_mode) && inode_unhashed(inode)) { |
25b7713a | 266 | inode->i_private = upperinode; |
bbb1e54d | 267 | __insert_inode_hash(inode, (unsigned long) upperinode); |
25b7713a | 268 | } |
bbb1e54d MS |
269 | } |
270 | ||
271 | void ovl_dentry_version_inc(struct dentry *dentry) | |
272 | { | |
04a01ac7 | 273 | struct inode *inode = d_inode(dentry); |
bbb1e54d | 274 | |
04a01ac7 MS |
275 | WARN_ON(!inode_is_locked(inode)); |
276 | OVL_I(inode)->version++; | |
bbb1e54d MS |
277 | } |
278 | ||
279 | u64 ovl_dentry_version_get(struct dentry *dentry) | |
280 | { | |
04a01ac7 | 281 | struct inode *inode = d_inode(dentry); |
bbb1e54d | 282 | |
04a01ac7 MS |
283 | WARN_ON(!inode_is_locked(inode)); |
284 | return OVL_I(inode)->version; | |
bbb1e54d MS |
285 | } |
286 | ||
287 | bool ovl_is_whiteout(struct dentry *dentry) | |
288 | { | |
289 | struct inode *inode = dentry->d_inode; | |
290 | ||
291 | return inode && IS_WHITEOUT(inode); | |
292 | } | |
293 | ||
294 | struct file *ovl_path_open(struct path *path, int flags) | |
295 | { | |
296 | return dentry_open(path, flags | O_NOATIME, current_cred()); | |
297 | } | |
39d3d60a AG |
298 | |
299 | int ovl_copy_up_start(struct dentry *dentry) | |
300 | { | |
a015dafc | 301 | struct ovl_inode *oi = OVL_I(d_inode(dentry)); |
39d3d60a AG |
302 | int err; |
303 | ||
a015dafc | 304 | err = mutex_lock_interruptible(&oi->lock); |
59be0971 | 305 | if (!err && ovl_dentry_has_upper_alias(dentry)) { |
a015dafc AG |
306 | err = 1; /* Already copied up */ |
307 | mutex_unlock(&oi->lock); | |
39d3d60a | 308 | } |
39d3d60a AG |
309 | |
310 | return err; | |
311 | } | |
312 | ||
313 | void ovl_copy_up_end(struct dentry *dentry) | |
314 | { | |
a015dafc | 315 | mutex_unlock(&OVL_I(d_inode(dentry))->lock); |
39d3d60a | 316 | } |
82b749b2 | 317 | |
f3a15685 AG |
318 | bool ovl_check_dir_xattr(struct dentry *dentry, const char *name) |
319 | { | |
320 | int res; | |
321 | char val; | |
322 | ||
323 | if (!d_is_dir(dentry)) | |
324 | return false; | |
325 | ||
326 | res = vfs_getxattr(dentry, name, &val, 1); | |
327 | if (res == 1 && val == 'y') | |
328 | return true; | |
329 | ||
330 | return false; | |
331 | } | |
332 | ||
82b749b2 AG |
333 | int ovl_check_setxattr(struct dentry *dentry, struct dentry *upperdentry, |
334 | const char *name, const void *value, size_t size, | |
335 | int xerr) | |
336 | { | |
337 | int err; | |
338 | struct ovl_fs *ofs = dentry->d_sb->s_fs_info; | |
339 | ||
340 | if (ofs->noxattr) | |
341 | return xerr; | |
342 | ||
343 | err = ovl_do_setxattr(upperdentry, name, value, size, 0); | |
344 | ||
345 | if (err == -EOPNOTSUPP) { | |
346 | pr_warn("overlayfs: cannot set %s xattr on upper\n", name); | |
347 | ofs->noxattr = true; | |
348 | return xerr; | |
349 | } | |
350 | ||
351 | return err; | |
352 | } | |
f3a15685 AG |
353 | |
354 | int ovl_set_impure(struct dentry *dentry, struct dentry *upperdentry) | |
355 | { | |
356 | int err; | |
f3a15685 | 357 | |
13c72075 | 358 | if (ovl_test_flag(OVL_IMPURE, d_inode(dentry))) |
f3a15685 AG |
359 | return 0; |
360 | ||
361 | /* | |
362 | * Do not fail when upper doesn't support xattrs. | |
363 | * Upper inodes won't have origin nor redirect xattr anyway. | |
364 | */ | |
365 | err = ovl_check_setxattr(dentry, upperdentry, OVL_XATTR_IMPURE, | |
366 | "y", 1, 0); | |
367 | if (!err) | |
13c72075 | 368 | ovl_set_flag(OVL_IMPURE, d_inode(dentry)); |
f3a15685 AG |
369 | |
370 | return err; | |
371 | } | |
13c72075 MS |
372 | |
373 | void ovl_set_flag(unsigned long flag, struct inode *inode) | |
374 | { | |
375 | set_bit(flag, &OVL_I(inode)->flags); | |
376 | } | |
377 | ||
378 | bool ovl_test_flag(unsigned long flag, struct inode *inode) | |
379 | { | |
380 | return test_bit(flag, &OVL_I(inode)->flags); | |
381 | } | |
ad0af710 AG |
382 | |
383 | /** | |
384 | * Caller must hold a reference to inode to prevent it from being freed while | |
385 | * it is marked inuse. | |
386 | */ | |
387 | bool ovl_inuse_trylock(struct dentry *dentry) | |
388 | { | |
389 | struct inode *inode = d_inode(dentry); | |
390 | bool locked = false; | |
391 | ||
392 | spin_lock(&inode->i_lock); | |
393 | if (!(inode->i_state & I_OVL_INUSE)) { | |
394 | inode->i_state |= I_OVL_INUSE; | |
395 | locked = true; | |
396 | } | |
397 | spin_unlock(&inode->i_lock); | |
398 | ||
399 | return locked; | |
400 | } | |
401 | ||
402 | void ovl_inuse_unlock(struct dentry *dentry) | |
403 | { | |
404 | if (dentry) { | |
405 | struct inode *inode = d_inode(dentry); | |
406 | ||
407 | spin_lock(&inode->i_lock); | |
408 | WARN_ON(!(inode->i_state & I_OVL_INUSE)); | |
409 | inode->i_state &= ~I_OVL_INUSE; | |
410 | spin_unlock(&inode->i_lock); | |
411 | } | |
412 | } |