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d2912cb1 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
e9be9d5e MS |
2 | /* |
3 | * | |
4 | * Copyright (C) 2011 Novell Inc. | |
e9be9d5e MS |
5 | */ |
6 | ||
5b825c3a | 7 | #include <uapi/linux/magic.h> |
e9be9d5e MS |
8 | #include <linux/fs.h> |
9 | #include <linux/namei.h> | |
10 | #include <linux/xattr.h> | |
e9be9d5e | 11 | #include <linux/mount.h> |
e9be9d5e MS |
12 | #include <linux/parser.h> |
13 | #include <linux/module.h> | |
cc259639 | 14 | #include <linux/statfs.h> |
f45827e8 | 15 | #include <linux/seq_file.h> |
d837a49b | 16 | #include <linux/posix_acl_xattr.h> |
e487d889 | 17 | #include <linux/exportfs.h> |
2b1a7746 | 18 | #include <linux/file.h> |
e9be9d5e MS |
19 | #include "overlayfs.h" |
20 | ||
21 | MODULE_AUTHOR("Miklos Szeredi <miklos@szeredi.hu>"); | |
22 | MODULE_DESCRIPTION("Overlay filesystem"); | |
23 | MODULE_LICENSE("GPL"); | |
24 | ||
e9be9d5e MS |
25 | |
26 | struct ovl_dir_cache; | |
27 | ||
a78d9f0d MS |
28 | #define OVL_MAX_STACK 500 |
29 | ||
688ea0e5 MS |
30 | static bool ovl_redirect_dir_def = IS_ENABLED(CONFIG_OVERLAY_FS_REDIRECT_DIR); |
31 | module_param_named(redirect_dir, ovl_redirect_dir_def, bool, 0644); | |
253e7483 | 32 | MODULE_PARM_DESC(redirect_dir, |
688ea0e5 | 33 | "Default to on or off for the redirect_dir feature"); |
e9be9d5e | 34 | |
438c84c2 MS |
35 | static bool ovl_redirect_always_follow = |
36 | IS_ENABLED(CONFIG_OVERLAY_FS_REDIRECT_ALWAYS_FOLLOW); | |
37 | module_param_named(redirect_always_follow, ovl_redirect_always_follow, | |
38 | bool, 0644); | |
253e7483 | 39 | MODULE_PARM_DESC(redirect_always_follow, |
438c84c2 MS |
40 | "Follow redirects even if redirect_dir feature is turned off"); |
41 | ||
02bcd157 AG |
42 | static bool ovl_index_def = IS_ENABLED(CONFIG_OVERLAY_FS_INDEX); |
43 | module_param_named(index, ovl_index_def, bool, 0644); | |
253e7483 | 44 | MODULE_PARM_DESC(index, |
02bcd157 AG |
45 | "Default to on or off for the inodes index feature"); |
46 | ||
f168f109 AG |
47 | static bool ovl_nfs_export_def = IS_ENABLED(CONFIG_OVERLAY_FS_NFS_EXPORT); |
48 | module_param_named(nfs_export, ovl_nfs_export_def, bool, 0644); | |
253e7483 | 49 | MODULE_PARM_DESC(nfs_export, |
f168f109 AG |
50 | "Default to on or off for the NFS export feature"); |
51 | ||
795939a9 AG |
52 | static bool ovl_xino_auto_def = IS_ENABLED(CONFIG_OVERLAY_FS_XINO_AUTO); |
53 | module_param_named(xino_auto, ovl_xino_auto_def, bool, 0644); | |
253e7483 | 54 | MODULE_PARM_DESC(xino_auto, |
795939a9 AG |
55 | "Auto enable xino feature"); |
56 | ||
4155c10a MS |
57 | static void ovl_entry_stack_free(struct ovl_entry *oe) |
58 | { | |
59 | unsigned int i; | |
60 | ||
61 | for (i = 0; i < oe->numlower; i++) | |
62 | dput(oe->lowerstack[i].dentry); | |
63 | } | |
64 | ||
d5791044 VG |
65 | static bool ovl_metacopy_def = IS_ENABLED(CONFIG_OVERLAY_FS_METACOPY); |
66 | module_param_named(metacopy, ovl_metacopy_def, bool, 0644); | |
253e7483 | 67 | MODULE_PARM_DESC(metacopy, |
d5791044 VG |
68 | "Default to on or off for the metadata only copy up feature"); |
69 | ||
e9be9d5e MS |
70 | static void ovl_dentry_release(struct dentry *dentry) |
71 | { | |
72 | struct ovl_entry *oe = dentry->d_fsdata; | |
73 | ||
74 | if (oe) { | |
4155c10a | 75 | ovl_entry_stack_free(oe); |
e9be9d5e MS |
76 | kfree_rcu(oe, rcu); |
77 | } | |
78 | } | |
79 | ||
2d902671 | 80 | static struct dentry *ovl_d_real(struct dentry *dentry, |
fb16043b | 81 | const struct inode *inode) |
d101a125 | 82 | { |
cef4cbff | 83 | struct dentry *real = NULL, *lower; |
d101a125 | 84 | |
e8c985ba MS |
85 | /* It's an overlay file */ |
86 | if (inode && d_inode(dentry) == inode) | |
87 | return dentry; | |
88 | ||
ca4c8a3a | 89 | if (!d_is_reg(dentry)) { |
d101a125 MS |
90 | if (!inode || inode == d_inode(dentry)) |
91 | return dentry; | |
92 | goto bug; | |
93 | } | |
94 | ||
95 | real = ovl_dentry_upper(dentry); | |
2c3d7358 | 96 | if (real && (inode == d_inode(real))) |
d101a125 MS |
97 | return real; |
98 | ||
2c3d7358 VG |
99 | if (real && !inode && ovl_has_upperdata(d_inode(dentry))) |
100 | return real; | |
101 | ||
cef4cbff MS |
102 | lower = ovl_dentry_lowerdata(dentry); |
103 | if (!lower) | |
d101a125 | 104 | goto bug; |
cef4cbff | 105 | real = lower; |
d101a125 | 106 | |
c4fcfc16 | 107 | /* Handle recursion */ |
fb16043b | 108 | real = d_real(real, inode); |
c4fcfc16 | 109 | |
d101a125 MS |
110 | if (!inode || inode == d_inode(real)) |
111 | return real; | |
d101a125 | 112 | bug: |
cef4cbff MS |
113 | WARN(1, "%s(%pd4, %s:%lu): real dentry (%p/%lu) not found\n", |
114 | __func__, dentry, inode ? inode->i_sb->s_id : "NULL", | |
115 | inode ? inode->i_ino : 0, real, | |
116 | real && d_inode(real) ? d_inode(real)->i_ino : 0); | |
d101a125 MS |
117 | return dentry; |
118 | } | |
119 | ||
3bb7df92 | 120 | static int ovl_revalidate_real(struct dentry *d, unsigned int flags, bool weak) |
7c03b5d4 | 121 | { |
7c03b5d4 MS |
122 | int ret = 1; |
123 | ||
3bb7df92 MS |
124 | if (weak) { |
125 | if (d->d_flags & DCACHE_OP_WEAK_REVALIDATE) | |
126 | ret = d->d_op->d_weak_revalidate(d, flags); | |
127 | } else if (d->d_flags & DCACHE_OP_REVALIDATE) { | |
128 | ret = d->d_op->d_revalidate(d, flags); | |
129 | if (!ret) { | |
130 | if (!(flags & LOOKUP_RCU)) | |
131 | d_invalidate(d); | |
132 | ret = -ESTALE; | |
7c03b5d4 MS |
133 | } |
134 | } | |
3bb7df92 | 135 | return ret; |
7c03b5d4 MS |
136 | } |
137 | ||
3bb7df92 MS |
138 | static int ovl_dentry_revalidate_common(struct dentry *dentry, |
139 | unsigned int flags, bool weak) | |
7c03b5d4 MS |
140 | { |
141 | struct ovl_entry *oe = dentry->d_fsdata; | |
672e4268 | 142 | struct inode *inode = d_inode_rcu(dentry); |
bccece1e | 143 | struct dentry *upper; |
7c03b5d4 MS |
144 | unsigned int i; |
145 | int ret = 1; | |
146 | ||
672e4268 CZ |
147 | /* Careful in RCU mode */ |
148 | if (!inode) | |
149 | return -ECHILD; | |
150 | ||
151 | upper = ovl_i_dentry_upper(inode); | |
bccece1e MS |
152 | if (upper) |
153 | ret = ovl_revalidate_real(upper, flags, weak); | |
154 | ||
3bb7df92 MS |
155 | for (i = 0; ret > 0 && i < oe->numlower; i++) { |
156 | ret = ovl_revalidate_real(oe->lowerstack[i].dentry, flags, | |
157 | weak); | |
7c03b5d4 MS |
158 | } |
159 | return ret; | |
160 | } | |
161 | ||
3bb7df92 MS |
162 | static int ovl_dentry_revalidate(struct dentry *dentry, unsigned int flags) |
163 | { | |
164 | return ovl_dentry_revalidate_common(dentry, flags, false); | |
165 | } | |
166 | ||
167 | static int ovl_dentry_weak_revalidate(struct dentry *dentry, unsigned int flags) | |
168 | { | |
169 | return ovl_dentry_revalidate_common(dentry, flags, true); | |
170 | } | |
171 | ||
e9be9d5e MS |
172 | static const struct dentry_operations ovl_dentry_operations = { |
173 | .d_release = ovl_dentry_release, | |
d101a125 | 174 | .d_real = ovl_d_real, |
7c03b5d4 MS |
175 | .d_revalidate = ovl_dentry_revalidate, |
176 | .d_weak_revalidate = ovl_dentry_weak_revalidate, | |
177 | }; | |
178 | ||
13cf199d AG |
179 | static struct kmem_cache *ovl_inode_cachep; |
180 | ||
181 | static struct inode *ovl_alloc_inode(struct super_block *sb) | |
182 | { | |
fd60b288 | 183 | struct ovl_inode *oi = alloc_inode_sb(sb, ovl_inode_cachep, GFP_KERNEL); |
13cf199d | 184 | |
b3885bd6 HN |
185 | if (!oi) |
186 | return NULL; | |
187 | ||
04a01ac7 | 188 | oi->cache = NULL; |
cf31c463 | 189 | oi->redirect = NULL; |
04a01ac7 | 190 | oi->version = 0; |
13c72075 | 191 | oi->flags = 0; |
09d8b586 | 192 | oi->__upperdentry = NULL; |
ffa5723c AG |
193 | oi->lowerpath.dentry = NULL; |
194 | oi->lowerpath.layer = NULL; | |
2664bd08 | 195 | oi->lowerdata = NULL; |
a015dafc | 196 | mutex_init(&oi->lock); |
25b7713a | 197 | |
13cf199d AG |
198 | return &oi->vfs_inode; |
199 | } | |
200 | ||
0b269ded | 201 | static void ovl_free_inode(struct inode *inode) |
13cf199d | 202 | { |
0b269ded | 203 | struct ovl_inode *oi = OVL_I(inode); |
13cf199d | 204 | |
0b269ded AV |
205 | kfree(oi->redirect); |
206 | mutex_destroy(&oi->lock); | |
207 | kmem_cache_free(ovl_inode_cachep, oi); | |
13cf199d AG |
208 | } |
209 | ||
210 | static void ovl_destroy_inode(struct inode *inode) | |
211 | { | |
09d8b586 MS |
212 | struct ovl_inode *oi = OVL_I(inode); |
213 | ||
214 | dput(oi->__upperdentry); | |
ffa5723c | 215 | dput(oi->lowerpath.dentry); |
2664bd08 VG |
216 | if (S_ISDIR(inode->i_mode)) |
217 | ovl_dir_cache_free(inode); | |
218 | else | |
219 | iput(oi->lowerdata); | |
13cf199d AG |
220 | } |
221 | ||
ad204488 | 222 | static void ovl_free_fs(struct ovl_fs *ofs) |
e9be9d5e | 223 | { |
df820f8d | 224 | struct vfsmount **mounts; |
dd662667 | 225 | unsigned i; |
e9be9d5e | 226 | |
0be0bfd2 | 227 | iput(ofs->workbasedir_trap); |
146d62e5 AG |
228 | iput(ofs->indexdir_trap); |
229 | iput(ofs->workdir_trap); | |
c21c839b | 230 | dput(ofs->whiteout); |
ad204488 MS |
231 | dput(ofs->indexdir); |
232 | dput(ofs->workdir); | |
233 | if (ofs->workdir_locked) | |
234 | ovl_inuse_unlock(ofs->workbasedir); | |
235 | dput(ofs->workbasedir); | |
236 | if (ofs->upperdir_locked) | |
08f4c7c8 | 237 | ovl_inuse_unlock(ovl_upper_mnt(ofs)->mnt_root); |
df820f8d MS |
238 | |
239 | /* Hack! Reuse ofs->layers as a vfsmount array before freeing it */ | |
240 | mounts = (struct vfsmount **) ofs->layers; | |
b8e42a65 | 241 | for (i = 0; i < ofs->numlayer; i++) { |
94375f9d | 242 | iput(ofs->layers[i].trap); |
df820f8d | 243 | mounts[i] = ofs->layers[i].mnt; |
146d62e5 | 244 | } |
df820f8d | 245 | kern_unmount_array(mounts, ofs->numlayer); |
94375f9d | 246 | kfree(ofs->layers); |
b7bf9908 | 247 | for (i = 0; i < ofs->numfs; i++) |
07f1e596 AG |
248 | free_anon_bdev(ofs->fs[i].pseudo_dev); |
249 | kfree(ofs->fs); | |
ad204488 MS |
250 | |
251 | kfree(ofs->config.lowerdir); | |
252 | kfree(ofs->config.upperdir); | |
253 | kfree(ofs->config.workdir); | |
438c84c2 | 254 | kfree(ofs->config.redirect_mode); |
ad204488 MS |
255 | if (ofs->creator_cred) |
256 | put_cred(ofs->creator_cred); | |
257 | kfree(ofs); | |
e9be9d5e MS |
258 | } |
259 | ||
a9075cdb MS |
260 | static void ovl_put_super(struct super_block *sb) |
261 | { | |
262 | struct ovl_fs *ofs = sb->s_fs_info; | |
263 | ||
264 | ovl_free_fs(ofs); | |
265 | } | |
266 | ||
e8d4bfe3 | 267 | /* Sync real dirty inodes in upper filesystem (if it exists) */ |
e593b2bf AG |
268 | static int ovl_sync_fs(struct super_block *sb, int wait) |
269 | { | |
ad204488 | 270 | struct ovl_fs *ofs = sb->s_fs_info; |
e593b2bf AG |
271 | struct super_block *upper_sb; |
272 | int ret; | |
273 | ||
335d3fc5 SD |
274 | ret = ovl_sync_status(ofs); |
275 | /* | |
276 | * We have to always set the err, because the return value isn't | |
277 | * checked in syncfs, and instead indirectly return an error via | |
278 | * the sb's writeback errseq, which VFS inspects after this call. | |
279 | */ | |
280 | if (ret < 0) { | |
281 | errseq_set(&sb->s_wb_err, -EIO); | |
282 | return -EIO; | |
283 | } | |
284 | ||
285 | if (!ret) | |
286 | return ret; | |
e8d4bfe3 CX |
287 | |
288 | /* | |
32b1924b KK |
289 | * Not called for sync(2) call or an emergency sync (SB_I_SKIP_SYNC). |
290 | * All the super blocks will be iterated, including upper_sb. | |
e8d4bfe3 CX |
291 | * |
292 | * If this is a syncfs(2) call, then we do need to call | |
293 | * sync_filesystem() on upper_sb, but enough if we do it when being | |
294 | * called with wait == 1. | |
295 | */ | |
296 | if (!wait) | |
e593b2bf AG |
297 | return 0; |
298 | ||
08f4c7c8 | 299 | upper_sb = ovl_upper_mnt(ofs)->mnt_sb; |
e8d4bfe3 | 300 | |
e593b2bf | 301 | down_read(&upper_sb->s_umount); |
e8d4bfe3 | 302 | ret = sync_filesystem(upper_sb); |
e593b2bf | 303 | up_read(&upper_sb->s_umount); |
e8d4bfe3 | 304 | |
e593b2bf AG |
305 | return ret; |
306 | } | |
307 | ||
cc259639 AW |
308 | /** |
309 | * ovl_statfs | |
9c5dd803 | 310 | * @dentry: The dentry to query |
cc259639 AW |
311 | * @buf: The struct kstatfs to fill in with stats |
312 | * | |
313 | * Get the filesystem statistics. As writes always target the upper layer | |
4ebc5818 | 314 | * filesystem pass the statfs to the upper filesystem (if it exists) |
cc259639 AW |
315 | */ |
316 | static int ovl_statfs(struct dentry *dentry, struct kstatfs *buf) | |
317 | { | |
318 | struct ovl_fs *ofs = dentry->d_sb->s_fs_info; | |
319 | struct dentry *root_dentry = dentry->d_sb->s_root; | |
320 | struct path path; | |
321 | int err; | |
322 | ||
4ebc5818 | 323 | ovl_path_real(root_dentry, &path); |
cc259639 AW |
324 | |
325 | err = vfs_statfs(&path, buf); | |
326 | if (!err) { | |
6b2d5fe4 | 327 | buf->f_namelen = ofs->namelen; |
cc259639 AW |
328 | buf->f_type = OVERLAYFS_SUPER_MAGIC; |
329 | } | |
330 | ||
331 | return err; | |
332 | } | |
333 | ||
02bcd157 | 334 | /* Will this overlay be forced to mount/remount ro? */ |
ad204488 | 335 | static bool ovl_force_readonly(struct ovl_fs *ofs) |
02bcd157 | 336 | { |
08f4c7c8 | 337 | return (!ovl_upper_mnt(ofs) || !ofs->workdir); |
02bcd157 AG |
338 | } |
339 | ||
438c84c2 MS |
340 | static const char *ovl_redirect_mode_def(void) |
341 | { | |
342 | return ovl_redirect_dir_def ? "on" : "off"; | |
343 | } | |
344 | ||
795939a9 AG |
345 | static const char * const ovl_xino_str[] = { |
346 | "off", | |
347 | "auto", | |
348 | "on", | |
349 | }; | |
350 | ||
351 | static inline int ovl_xino_def(void) | |
352 | { | |
353 | return ovl_xino_auto_def ? OVL_XINO_AUTO : OVL_XINO_OFF; | |
354 | } | |
355 | ||
f45827e8 EZ |
356 | /** |
357 | * ovl_show_options | |
9c5dd803 YL |
358 | * @m: the seq_file handle |
359 | * @dentry: The dentry to query | |
f45827e8 EZ |
360 | * |
361 | * Prints the mount options for a given superblock. | |
362 | * Returns zero; does not fail. | |
363 | */ | |
364 | static int ovl_show_options(struct seq_file *m, struct dentry *dentry) | |
365 | { | |
366 | struct super_block *sb = dentry->d_sb; | |
ad204488 | 367 | struct ovl_fs *ofs = sb->s_fs_info; |
f45827e8 | 368 | |
ad204488 MS |
369 | seq_show_option(m, "lowerdir", ofs->config.lowerdir); |
370 | if (ofs->config.upperdir) { | |
371 | seq_show_option(m, "upperdir", ofs->config.upperdir); | |
372 | seq_show_option(m, "workdir", ofs->config.workdir); | |
53a08cb9 | 373 | } |
ad204488 | 374 | if (ofs->config.default_permissions) |
8d3095f4 | 375 | seq_puts(m, ",default_permissions"); |
438c84c2 MS |
376 | if (strcmp(ofs->config.redirect_mode, ovl_redirect_mode_def()) != 0) |
377 | seq_printf(m, ",redirect_dir=%s", ofs->config.redirect_mode); | |
ad204488 | 378 | if (ofs->config.index != ovl_index_def) |
438c84c2 | 379 | seq_printf(m, ",index=%s", ofs->config.index ? "on" : "off"); |
5830fb6b PT |
380 | if (!ofs->config.uuid) |
381 | seq_puts(m, ",uuid=off"); | |
f168f109 AG |
382 | if (ofs->config.nfs_export != ovl_nfs_export_def) |
383 | seq_printf(m, ",nfs_export=%s", ofs->config.nfs_export ? | |
384 | "on" : "off"); | |
0f831ec8 | 385 | if (ofs->config.xino != ovl_xino_def() && !ovl_same_fs(sb)) |
795939a9 | 386 | seq_printf(m, ",xino=%s", ovl_xino_str[ofs->config.xino]); |
d5791044 VG |
387 | if (ofs->config.metacopy != ovl_metacopy_def) |
388 | seq_printf(m, ",metacopy=%s", | |
389 | ofs->config.metacopy ? "on" : "off"); | |
c86243b0 VG |
390 | if (ofs->config.ovl_volatile) |
391 | seq_puts(m, ",volatile"); | |
321b46b9 GS |
392 | if (ofs->config.userxattr) |
393 | seq_puts(m, ",userxattr"); | |
f45827e8 EZ |
394 | return 0; |
395 | } | |
396 | ||
3cdf6fe9 SL |
397 | static int ovl_remount(struct super_block *sb, int *flags, char *data) |
398 | { | |
ad204488 | 399 | struct ovl_fs *ofs = sb->s_fs_info; |
399c109d CX |
400 | struct super_block *upper_sb; |
401 | int ret = 0; | |
3cdf6fe9 | 402 | |
1751e8a6 | 403 | if (!(*flags & SB_RDONLY) && ovl_force_readonly(ofs)) |
3cdf6fe9 SL |
404 | return -EROFS; |
405 | ||
399c109d | 406 | if (*flags & SB_RDONLY && !sb_rdonly(sb)) { |
08f4c7c8 | 407 | upper_sb = ovl_upper_mnt(ofs)->mnt_sb; |
c86243b0 VG |
408 | if (ovl_should_sync(ofs)) { |
409 | down_read(&upper_sb->s_umount); | |
410 | ret = sync_filesystem(upper_sb); | |
411 | up_read(&upper_sb->s_umount); | |
412 | } | |
399c109d CX |
413 | } |
414 | ||
415 | return ret; | |
3cdf6fe9 SL |
416 | } |
417 | ||
e9be9d5e | 418 | static const struct super_operations ovl_super_operations = { |
13cf199d | 419 | .alloc_inode = ovl_alloc_inode, |
0b269ded | 420 | .free_inode = ovl_free_inode, |
13cf199d AG |
421 | .destroy_inode = ovl_destroy_inode, |
422 | .drop_inode = generic_delete_inode, | |
e9be9d5e | 423 | .put_super = ovl_put_super, |
e593b2bf | 424 | .sync_fs = ovl_sync_fs, |
cc259639 | 425 | .statfs = ovl_statfs, |
f45827e8 | 426 | .show_options = ovl_show_options, |
3cdf6fe9 | 427 | .remount_fs = ovl_remount, |
e9be9d5e MS |
428 | }; |
429 | ||
430 | enum { | |
431 | OPT_LOWERDIR, | |
432 | OPT_UPPERDIR, | |
433 | OPT_WORKDIR, | |
8d3095f4 | 434 | OPT_DEFAULT_PERMISSIONS, |
438c84c2 | 435 | OPT_REDIRECT_DIR, |
02bcd157 AG |
436 | OPT_INDEX_ON, |
437 | OPT_INDEX_OFF, | |
5830fb6b PT |
438 | OPT_UUID_ON, |
439 | OPT_UUID_OFF, | |
f168f109 | 440 | OPT_NFS_EXPORT_ON, |
2d2f2d73 | 441 | OPT_USERXATTR, |
f168f109 | 442 | OPT_NFS_EXPORT_OFF, |
795939a9 AG |
443 | OPT_XINO_ON, |
444 | OPT_XINO_OFF, | |
445 | OPT_XINO_AUTO, | |
d5791044 VG |
446 | OPT_METACOPY_ON, |
447 | OPT_METACOPY_OFF, | |
c86243b0 | 448 | OPT_VOLATILE, |
e9be9d5e MS |
449 | OPT_ERR, |
450 | }; | |
451 | ||
452 | static const match_table_t ovl_tokens = { | |
453 | {OPT_LOWERDIR, "lowerdir=%s"}, | |
454 | {OPT_UPPERDIR, "upperdir=%s"}, | |
455 | {OPT_WORKDIR, "workdir=%s"}, | |
8d3095f4 | 456 | {OPT_DEFAULT_PERMISSIONS, "default_permissions"}, |
438c84c2 | 457 | {OPT_REDIRECT_DIR, "redirect_dir=%s"}, |
02bcd157 AG |
458 | {OPT_INDEX_ON, "index=on"}, |
459 | {OPT_INDEX_OFF, "index=off"}, | |
2d2f2d73 | 460 | {OPT_USERXATTR, "userxattr"}, |
5830fb6b PT |
461 | {OPT_UUID_ON, "uuid=on"}, |
462 | {OPT_UUID_OFF, "uuid=off"}, | |
f168f109 AG |
463 | {OPT_NFS_EXPORT_ON, "nfs_export=on"}, |
464 | {OPT_NFS_EXPORT_OFF, "nfs_export=off"}, | |
795939a9 AG |
465 | {OPT_XINO_ON, "xino=on"}, |
466 | {OPT_XINO_OFF, "xino=off"}, | |
467 | {OPT_XINO_AUTO, "xino=auto"}, | |
d5791044 VG |
468 | {OPT_METACOPY_ON, "metacopy=on"}, |
469 | {OPT_METACOPY_OFF, "metacopy=off"}, | |
c86243b0 | 470 | {OPT_VOLATILE, "volatile"}, |
e9be9d5e MS |
471 | {OPT_ERR, NULL} |
472 | }; | |
473 | ||
91c77947 MS |
474 | static char *ovl_next_opt(char **s) |
475 | { | |
476 | char *sbegin = *s; | |
477 | char *p; | |
478 | ||
479 | if (sbegin == NULL) | |
480 | return NULL; | |
481 | ||
482 | for (p = sbegin; *p; p++) { | |
483 | if (*p == '\\') { | |
484 | p++; | |
485 | if (!*p) | |
486 | break; | |
487 | } else if (*p == ',') { | |
488 | *p = '\0'; | |
489 | *s = p + 1; | |
490 | return sbegin; | |
491 | } | |
492 | } | |
493 | *s = NULL; | |
494 | return sbegin; | |
495 | } | |
496 | ||
438c84c2 MS |
497 | static int ovl_parse_redirect_mode(struct ovl_config *config, const char *mode) |
498 | { | |
499 | if (strcmp(mode, "on") == 0) { | |
500 | config->redirect_dir = true; | |
501 | /* | |
502 | * Does not make sense to have redirect creation without | |
503 | * redirect following. | |
504 | */ | |
505 | config->redirect_follow = true; | |
506 | } else if (strcmp(mode, "follow") == 0) { | |
507 | config->redirect_follow = true; | |
508 | } else if (strcmp(mode, "off") == 0) { | |
509 | if (ovl_redirect_always_follow) | |
510 | config->redirect_follow = true; | |
511 | } else if (strcmp(mode, "nofollow") != 0) { | |
1bd0a3ae | 512 | pr_err("bad mount option \"redirect_dir=%s\"\n", |
438c84c2 MS |
513 | mode); |
514 | return -EINVAL; | |
515 | } | |
516 | ||
517 | return 0; | |
518 | } | |
519 | ||
e9be9d5e MS |
520 | static int ovl_parse_opt(char *opt, struct ovl_config *config) |
521 | { | |
522 | char *p; | |
d5791044 | 523 | int err; |
d47748e5 | 524 | bool metacopy_opt = false, redirect_opt = false; |
b0def88d | 525 | bool nfs_export_opt = false, index_opt = false; |
e9be9d5e | 526 | |
438c84c2 MS |
527 | config->redirect_mode = kstrdup(ovl_redirect_mode_def(), GFP_KERNEL); |
528 | if (!config->redirect_mode) | |
529 | return -ENOMEM; | |
530 | ||
91c77947 | 531 | while ((p = ovl_next_opt(&opt)) != NULL) { |
e9be9d5e MS |
532 | int token; |
533 | substring_t args[MAX_OPT_ARGS]; | |
534 | ||
535 | if (!*p) | |
536 | continue; | |
537 | ||
538 | token = match_token(p, ovl_tokens, args); | |
539 | switch (token) { | |
540 | case OPT_UPPERDIR: | |
541 | kfree(config->upperdir); | |
542 | config->upperdir = match_strdup(&args[0]); | |
543 | if (!config->upperdir) | |
544 | return -ENOMEM; | |
545 | break; | |
546 | ||
547 | case OPT_LOWERDIR: | |
548 | kfree(config->lowerdir); | |
549 | config->lowerdir = match_strdup(&args[0]); | |
550 | if (!config->lowerdir) | |
551 | return -ENOMEM; | |
552 | break; | |
553 | ||
554 | case OPT_WORKDIR: | |
555 | kfree(config->workdir); | |
556 | config->workdir = match_strdup(&args[0]); | |
557 | if (!config->workdir) | |
558 | return -ENOMEM; | |
559 | break; | |
560 | ||
8d3095f4 MS |
561 | case OPT_DEFAULT_PERMISSIONS: |
562 | config->default_permissions = true; | |
563 | break; | |
564 | ||
438c84c2 MS |
565 | case OPT_REDIRECT_DIR: |
566 | kfree(config->redirect_mode); | |
567 | config->redirect_mode = match_strdup(&args[0]); | |
568 | if (!config->redirect_mode) | |
569 | return -ENOMEM; | |
d47748e5 | 570 | redirect_opt = true; |
a6c60655 MS |
571 | break; |
572 | ||
02bcd157 AG |
573 | case OPT_INDEX_ON: |
574 | config->index = true; | |
b0def88d | 575 | index_opt = true; |
02bcd157 AG |
576 | break; |
577 | ||
578 | case OPT_INDEX_OFF: | |
579 | config->index = false; | |
b0def88d | 580 | index_opt = true; |
02bcd157 AG |
581 | break; |
582 | ||
5830fb6b PT |
583 | case OPT_UUID_ON: |
584 | config->uuid = true; | |
585 | break; | |
586 | ||
587 | case OPT_UUID_OFF: | |
588 | config->uuid = false; | |
589 | break; | |
590 | ||
f168f109 AG |
591 | case OPT_NFS_EXPORT_ON: |
592 | config->nfs_export = true; | |
b0def88d | 593 | nfs_export_opt = true; |
f168f109 AG |
594 | break; |
595 | ||
596 | case OPT_NFS_EXPORT_OFF: | |
597 | config->nfs_export = false; | |
b0def88d | 598 | nfs_export_opt = true; |
f168f109 AG |
599 | break; |
600 | ||
795939a9 AG |
601 | case OPT_XINO_ON: |
602 | config->xino = OVL_XINO_ON; | |
603 | break; | |
604 | ||
605 | case OPT_XINO_OFF: | |
606 | config->xino = OVL_XINO_OFF; | |
607 | break; | |
608 | ||
609 | case OPT_XINO_AUTO: | |
610 | config->xino = OVL_XINO_AUTO; | |
611 | break; | |
612 | ||
d5791044 VG |
613 | case OPT_METACOPY_ON: |
614 | config->metacopy = true; | |
d47748e5 | 615 | metacopy_opt = true; |
d5791044 VG |
616 | break; |
617 | ||
618 | case OPT_METACOPY_OFF: | |
619 | config->metacopy = false; | |
b0def88d | 620 | metacopy_opt = true; |
d5791044 VG |
621 | break; |
622 | ||
c86243b0 VG |
623 | case OPT_VOLATILE: |
624 | config->ovl_volatile = true; | |
625 | break; | |
626 | ||
2d2f2d73 MS |
627 | case OPT_USERXATTR: |
628 | config->userxattr = true; | |
629 | break; | |
630 | ||
e9be9d5e | 631 | default: |
1bd0a3ae | 632 | pr_err("unrecognized mount option \"%s\" or missing value\n", |
633 | p); | |
e9be9d5e MS |
634 | return -EINVAL; |
635 | } | |
636 | } | |
71cbad7e | 637 | |
f0e1266e AG |
638 | /* Workdir/index are useless in non-upper mount */ |
639 | if (!config->upperdir) { | |
640 | if (config->workdir) { | |
641 | pr_info("option \"workdir=%s\" is useless in a non-upper mount, ignore\n", | |
642 | config->workdir); | |
643 | kfree(config->workdir); | |
644 | config->workdir = NULL; | |
645 | } | |
646 | if (config->index && index_opt) { | |
647 | pr_info("option \"index=on\" is useless in a non-upper mount, ignore\n"); | |
648 | index_opt = false; | |
649 | } | |
650 | config->index = false; | |
71cbad7e | 651 | } |
652 | ||
c86243b0 VG |
653 | if (!config->upperdir && config->ovl_volatile) { |
654 | pr_info("option \"volatile\" is meaningless in a non-upper mount, ignoring it.\n"); | |
655 | config->ovl_volatile = false; | |
656 | } | |
657 | ||
d5791044 VG |
658 | err = ovl_parse_redirect_mode(config, config->redirect_mode); |
659 | if (err) | |
660 | return err; | |
661 | ||
d47748e5 MS |
662 | /* |
663 | * This is to make the logic below simpler. It doesn't make any other | |
664 | * difference, since config->redirect_dir is only used for upper. | |
665 | */ | |
666 | if (!config->upperdir && config->redirect_follow) | |
667 | config->redirect_dir = true; | |
668 | ||
669 | /* Resolve metacopy -> redirect_dir dependency */ | |
670 | if (config->metacopy && !config->redirect_dir) { | |
671 | if (metacopy_opt && redirect_opt) { | |
1bd0a3ae | 672 | pr_err("conflicting options: metacopy=on,redirect_dir=%s\n", |
d47748e5 MS |
673 | config->redirect_mode); |
674 | return -EINVAL; | |
675 | } | |
676 | if (redirect_opt) { | |
677 | /* | |
678 | * There was an explicit redirect_dir=... that resulted | |
679 | * in this conflict. | |
680 | */ | |
1bd0a3ae | 681 | pr_info("disabling metacopy due to redirect_dir=%s\n", |
d47748e5 MS |
682 | config->redirect_mode); |
683 | config->metacopy = false; | |
684 | } else { | |
685 | /* Automatically enable redirect otherwise. */ | |
686 | config->redirect_follow = config->redirect_dir = true; | |
687 | } | |
d5791044 VG |
688 | } |
689 | ||
b0def88d AG |
690 | /* Resolve nfs_export -> index dependency */ |
691 | if (config->nfs_export && !config->index) { | |
f0e1266e AG |
692 | if (!config->upperdir && config->redirect_follow) { |
693 | pr_info("NFS export requires \"redirect_dir=nofollow\" on non-upper mount, falling back to nfs_export=off.\n"); | |
694 | config->nfs_export = false; | |
695 | } else if (nfs_export_opt && index_opt) { | |
b0def88d AG |
696 | pr_err("conflicting options: nfs_export=on,index=off\n"); |
697 | return -EINVAL; | |
f0e1266e | 698 | } else if (index_opt) { |
b0def88d AG |
699 | /* |
700 | * There was an explicit index=off that resulted | |
701 | * in this conflict. | |
702 | */ | |
703 | pr_info("disabling nfs_export due to index=off\n"); | |
704 | config->nfs_export = false; | |
705 | } else { | |
706 | /* Automatically enable index otherwise. */ | |
707 | config->index = true; | |
708 | } | |
709 | } | |
710 | ||
711 | /* Resolve nfs_export -> !metacopy dependency */ | |
712 | if (config->nfs_export && config->metacopy) { | |
713 | if (nfs_export_opt && metacopy_opt) { | |
714 | pr_err("conflicting options: nfs_export=on,metacopy=on\n"); | |
715 | return -EINVAL; | |
716 | } | |
717 | if (metacopy_opt) { | |
718 | /* | |
719 | * There was an explicit metacopy=on that resulted | |
720 | * in this conflict. | |
721 | */ | |
722 | pr_info("disabling nfs_export due to metacopy=on\n"); | |
723 | config->nfs_export = false; | |
724 | } else { | |
725 | /* | |
726 | * There was an explicit nfs_export=on that resulted | |
727 | * in this conflict. | |
728 | */ | |
729 | pr_info("disabling metacopy due to nfs_export=on\n"); | |
730 | config->metacopy = false; | |
731 | } | |
732 | } | |
733 | ||
2d2f2d73 MS |
734 | |
735 | /* Resolve userxattr -> !redirect && !metacopy dependency */ | |
736 | if (config->userxattr) { | |
737 | if (config->redirect_follow && redirect_opt) { | |
738 | pr_err("conflicting options: userxattr,redirect_dir=%s\n", | |
739 | config->redirect_mode); | |
740 | return -EINVAL; | |
741 | } | |
742 | if (config->metacopy && metacopy_opt) { | |
743 | pr_err("conflicting options: userxattr,metacopy=on\n"); | |
744 | return -EINVAL; | |
745 | } | |
746 | /* | |
747 | * Silently disable default setting of redirect and metacopy. | |
748 | * This shall be the default in the future as well: these | |
749 | * options must be explicitly enabled if used together with | |
750 | * userxattr. | |
751 | */ | |
752 | config->redirect_dir = config->redirect_follow = false; | |
753 | config->metacopy = false; | |
754 | } | |
755 | ||
d5791044 | 756 | return 0; |
e9be9d5e MS |
757 | } |
758 | ||
759 | #define OVL_WORKDIR_NAME "work" | |
02bcd157 | 760 | #define OVL_INDEXDIR_NAME "index" |
e9be9d5e | 761 | |
ad204488 | 762 | static struct dentry *ovl_workdir_create(struct ovl_fs *ofs, |
6b8aa129 | 763 | const char *name, bool persist) |
e9be9d5e | 764 | { |
ad204488 | 765 | struct inode *dir = ofs->workbasedir->d_inode; |
08f4c7c8 | 766 | struct vfsmount *mnt = ovl_upper_mnt(ofs); |
e9be9d5e MS |
767 | struct dentry *work; |
768 | int err; | |
769 | bool retried = false; | |
770 | ||
5955102c | 771 | inode_lock_nested(dir, I_MUTEX_PARENT); |
e9be9d5e | 772 | retry: |
22f289ce | 773 | work = ovl_lookup_upper(ofs, name, ofs->workbasedir, strlen(name)); |
e9be9d5e MS |
774 | |
775 | if (!IS_ERR(work)) { | |
c11b9fdd MS |
776 | struct iattr attr = { |
777 | .ia_valid = ATTR_MODE, | |
32a3d848 | 778 | .ia_mode = S_IFDIR | 0, |
c11b9fdd | 779 | }; |
e9be9d5e MS |
780 | |
781 | if (work->d_inode) { | |
782 | err = -EEXIST; | |
783 | if (retried) | |
784 | goto out_dput; | |
785 | ||
6b8aa129 AG |
786 | if (persist) |
787 | goto out_unlock; | |
788 | ||
e9be9d5e | 789 | retried = true; |
576bb263 | 790 | err = ovl_workdir_cleanup(ofs, dir, mnt, work, 0); |
e9be9d5e | 791 | dput(work); |
235ce9ed AG |
792 | if (err == -EINVAL) { |
793 | work = ERR_PTR(err); | |
794 | goto out_unlock; | |
795 | } | |
e9be9d5e MS |
796 | goto retry; |
797 | } | |
798 | ||
576bb263 | 799 | err = ovl_mkdir_real(ofs, dir, &work, attr.ia_mode); |
1f5573cf MS |
800 | if (err) |
801 | goto out_dput; | |
802 | ||
803 | /* Weird filesystem returning with hashed negative (kernfs)? */ | |
804 | err = -EINVAL; | |
805 | if (d_really_is_negative(work)) | |
806 | goto out_dput; | |
c11b9fdd | 807 | |
cb348edb MS |
808 | /* |
809 | * Try to remove POSIX ACL xattrs from workdir. We are good if: | |
810 | * | |
811 | * a) success (there was a POSIX ACL xattr and was removed) | |
812 | * b) -ENODATA (there was no POSIX ACL xattr) | |
813 | * c) -EOPNOTSUPP (POSIX ACL xattrs are not supported) | |
814 | * | |
815 | * There are various other error values that could effectively | |
816 | * mean that the xattr doesn't exist (e.g. -ERANGE is returned | |
817 | * if the xattr name is too long), but the set of filesystems | |
818 | * allowed as upper are limited to "normal" ones, where checking | |
819 | * for the above two errors is sufficient. | |
820 | */ | |
31acceb9 | 821 | err = ovl_do_remove_acl(ofs, work, XATTR_NAME_POSIX_ACL_DEFAULT); |
e1ff3dd1 | 822 | if (err && err != -ENODATA && err != -EOPNOTSUPP) |
c11b9fdd MS |
823 | goto out_dput; |
824 | ||
31acceb9 | 825 | err = ovl_do_remove_acl(ofs, work, XATTR_NAME_POSIX_ACL_ACCESS); |
e1ff3dd1 | 826 | if (err && err != -ENODATA && err != -EOPNOTSUPP) |
c11b9fdd MS |
827 | goto out_dput; |
828 | ||
829 | /* Clear any inherited mode bits */ | |
830 | inode_lock(work->d_inode); | |
a15506ea | 831 | err = ovl_do_notify_change(ofs, work, &attr); |
c11b9fdd MS |
832 | inode_unlock(work->d_inode); |
833 | if (err) | |
834 | goto out_dput; | |
6b8aa129 AG |
835 | } else { |
836 | err = PTR_ERR(work); | |
837 | goto out_err; | |
e9be9d5e MS |
838 | } |
839 | out_unlock: | |
2068cf7d | 840 | inode_unlock(dir); |
e9be9d5e MS |
841 | return work; |
842 | ||
843 | out_dput: | |
844 | dput(work); | |
6b8aa129 | 845 | out_err: |
1bd0a3ae | 846 | pr_warn("failed to create directory %s/%s (errno: %i); mounting read-only\n", |
ad204488 | 847 | ofs->config.workdir, name, -err); |
6b8aa129 | 848 | work = NULL; |
e9be9d5e MS |
849 | goto out_unlock; |
850 | } | |
851 | ||
91c77947 MS |
852 | static void ovl_unescape(char *s) |
853 | { | |
854 | char *d = s; | |
855 | ||
856 | for (;; s++, d++) { | |
857 | if (*s == '\\') | |
858 | s++; | |
859 | *d = *s; | |
860 | if (!*s) | |
861 | break; | |
862 | } | |
863 | } | |
864 | ||
ab508822 MS |
865 | static int ovl_mount_dir_noesc(const char *name, struct path *path) |
866 | { | |
a78d9f0d | 867 | int err = -EINVAL; |
ab508822 | 868 | |
a78d9f0d | 869 | if (!*name) { |
1bd0a3ae | 870 | pr_err("empty lowerdir\n"); |
a78d9f0d MS |
871 | goto out; |
872 | } | |
ab508822 MS |
873 | err = kern_path(name, LOOKUP_FOLLOW, path); |
874 | if (err) { | |
1bd0a3ae | 875 | pr_err("failed to resolve '%s': %i\n", name, err); |
ab508822 MS |
876 | goto out; |
877 | } | |
878 | err = -EINVAL; | |
7c03b5d4 | 879 | if (ovl_dentry_weird(path->dentry)) { |
1bd0a3ae | 880 | pr_err("filesystem on '%s' not supported\n", name); |
ab508822 MS |
881 | goto out_put; |
882 | } | |
2b8c30e9 | 883 | if (!d_is_dir(path->dentry)) { |
1bd0a3ae | 884 | pr_err("'%s' not a directory\n", name); |
ab508822 MS |
885 | goto out_put; |
886 | } | |
887 | return 0; | |
888 | ||
889 | out_put: | |
8aafcb59 | 890 | path_put_init(path); |
ab508822 MS |
891 | out: |
892 | return err; | |
893 | } | |
894 | ||
895 | static int ovl_mount_dir(const char *name, struct path *path) | |
896 | { | |
897 | int err = -ENOMEM; | |
898 | char *tmp = kstrdup(name, GFP_KERNEL); | |
899 | ||
900 | if (tmp) { | |
901 | ovl_unescape(tmp); | |
902 | err = ovl_mount_dir_noesc(tmp, path); | |
7c03b5d4 | 903 | |
bccece1e | 904 | if (!err && path->dentry->d_flags & DCACHE_OP_REAL) { |
7925dad8 MS |
905 | pr_err("filesystem on '%s' not supported as upperdir\n", |
906 | tmp); | |
907 | path_put_init(path); | |
908 | err = -EINVAL; | |
909 | } | |
ab508822 MS |
910 | kfree(tmp); |
911 | } | |
912 | return err; | |
913 | } | |
914 | ||
2d343087 | 915 | static int ovl_check_namelen(const struct path *path, struct ovl_fs *ofs, |
6b2d5fe4 | 916 | const char *name) |
ab508822 | 917 | { |
ab508822 | 918 | struct kstatfs statfs; |
6b2d5fe4 MS |
919 | int err = vfs_statfs(path, &statfs); |
920 | ||
921 | if (err) | |
1bd0a3ae | 922 | pr_err("statfs failed on '%s'\n", name); |
6b2d5fe4 MS |
923 | else |
924 | ofs->namelen = max(ofs->namelen, statfs.f_namelen); | |
925 | ||
926 | return err; | |
927 | } | |
928 | ||
929 | static int ovl_lower_dir(const char *name, struct path *path, | |
f4288844 | 930 | struct ovl_fs *ofs, int *stack_depth) |
6b2d5fe4 | 931 | { |
e487d889 | 932 | int fh_type; |
6b2d5fe4 | 933 | int err; |
ab508822 | 934 | |
a78d9f0d | 935 | err = ovl_mount_dir_noesc(name, path); |
ab508822 | 936 | if (err) |
b8e42a65 | 937 | return err; |
ab508822 | 938 | |
6b2d5fe4 MS |
939 | err = ovl_check_namelen(path, ofs, name); |
940 | if (err) | |
b8e42a65 | 941 | return err; |
6b2d5fe4 | 942 | |
ab508822 MS |
943 | *stack_depth = max(*stack_depth, path->mnt->mnt_sb->s_stack_depth); |
944 | ||
02bcd157 | 945 | /* |
f168f109 AG |
946 | * The inodes index feature and NFS export need to encode and decode |
947 | * file handles, so they require that all layers support them. | |
02bcd157 | 948 | */ |
e487d889 | 949 | fh_type = ovl_can_decode_fh(path->dentry->d_sb); |
f168f109 | 950 | if ((ofs->config.nfs_export || |
e487d889 | 951 | (ofs->config.index && ofs->config.upperdir)) && !fh_type) { |
02bcd157 | 952 | ofs->config.index = false; |
f168f109 | 953 | ofs->config.nfs_export = false; |
1bd0a3ae | 954 | pr_warn("fs on '%s' does not support file handles, falling back to index=off,nfs_export=off.\n", |
f168f109 | 955 | name); |
02bcd157 | 956 | } |
b0e0f697 AG |
957 | /* |
958 | * Decoding origin file handle is required for persistent st_ino. | |
959 | * Without persistent st_ino, xino=auto falls back to xino=off. | |
960 | */ | |
961 | if (ofs->config.xino == OVL_XINO_AUTO && | |
962 | ofs->config.upperdir && !fh_type) { | |
963 | ofs->config.xino = OVL_XINO_OFF; | |
964 | pr_warn("fs on '%s' does not support file handles, falling back to xino=off.\n", | |
965 | name); | |
966 | } | |
02bcd157 | 967 | |
e487d889 AG |
968 | /* Check if lower fs has 32bit inode numbers */ |
969 | if (fh_type != FILEID_INO32_GEN) | |
0f831ec8 | 970 | ofs->xino_mode = -1; |
e487d889 | 971 | |
ab508822 | 972 | return 0; |
ab508822 MS |
973 | } |
974 | ||
e9be9d5e MS |
975 | /* Workdir should not be subdir of upperdir and vice versa */ |
976 | static bool ovl_workdir_ok(struct dentry *workdir, struct dentry *upperdir) | |
977 | { | |
978 | bool ok = false; | |
979 | ||
980 | if (workdir != upperdir) { | |
981 | ok = (lock_rename(workdir, upperdir) == NULL); | |
982 | unlock_rename(workdir, upperdir); | |
983 | } | |
984 | return ok; | |
985 | } | |
986 | ||
a78d9f0d MS |
987 | static unsigned int ovl_split_lowerdirs(char *str) |
988 | { | |
989 | unsigned int ctr = 1; | |
990 | char *s, *d; | |
991 | ||
992 | for (s = d = str;; s++, d++) { | |
993 | if (*s == '\\') { | |
994 | s++; | |
995 | } else if (*s == ':') { | |
996 | *d = '\0'; | |
997 | ctr++; | |
998 | continue; | |
999 | } | |
1000 | *d = *s; | |
1001 | if (!*s) | |
1002 | break; | |
1003 | } | |
1004 | return ctr; | |
1005 | } | |
1006 | ||
0eb45fc3 AG |
1007 | static int ovl_own_xattr_get(const struct xattr_handler *handler, |
1008 | struct dentry *dentry, struct inode *inode, | |
1009 | const char *name, void *buffer, size_t size) | |
1010 | { | |
48fab5d7 | 1011 | return -EOPNOTSUPP; |
0eb45fc3 AG |
1012 | } |
1013 | ||
d837a49b | 1014 | static int ovl_own_xattr_set(const struct xattr_handler *handler, |
39f60c1c | 1015 | struct mnt_idmap *idmap, |
d837a49b MS |
1016 | struct dentry *dentry, struct inode *inode, |
1017 | const char *name, const void *value, | |
1018 | size_t size, int flags) | |
1019 | { | |
48fab5d7 | 1020 | return -EOPNOTSUPP; |
d837a49b MS |
1021 | } |
1022 | ||
0eb45fc3 AG |
1023 | static int ovl_other_xattr_get(const struct xattr_handler *handler, |
1024 | struct dentry *dentry, struct inode *inode, | |
1025 | const char *name, void *buffer, size_t size) | |
1026 | { | |
1d88f183 | 1027 | return ovl_xattr_get(dentry, inode, name, buffer, size); |
0eb45fc3 AG |
1028 | } |
1029 | ||
0e585ccc | 1030 | static int ovl_other_xattr_set(const struct xattr_handler *handler, |
39f60c1c | 1031 | struct mnt_idmap *idmap, |
0e585ccc AG |
1032 | struct dentry *dentry, struct inode *inode, |
1033 | const char *name, const void *value, | |
1034 | size_t size, int flags) | |
1035 | { | |
1d88f183 | 1036 | return ovl_xattr_set(dentry, inode, name, value, size, flags); |
0e585ccc AG |
1037 | } |
1038 | ||
2d2f2d73 MS |
1039 | static const struct xattr_handler ovl_own_trusted_xattr_handler = { |
1040 | .prefix = OVL_XATTR_TRUSTED_PREFIX, | |
1041 | .get = ovl_own_xattr_get, | |
1042 | .set = ovl_own_xattr_set, | |
1043 | }; | |
1044 | ||
1045 | static const struct xattr_handler ovl_own_user_xattr_handler = { | |
1046 | .prefix = OVL_XATTR_USER_PREFIX, | |
0eb45fc3 | 1047 | .get = ovl_own_xattr_get, |
d837a49b MS |
1048 | .set = ovl_own_xattr_set, |
1049 | }; | |
1050 | ||
1051 | static const struct xattr_handler ovl_other_xattr_handler = { | |
1052 | .prefix = "", /* catch all */ | |
0eb45fc3 | 1053 | .get = ovl_other_xattr_get, |
d837a49b MS |
1054 | .set = ovl_other_xattr_set, |
1055 | }; | |
1056 | ||
2d2f2d73 | 1057 | static const struct xattr_handler *ovl_trusted_xattr_handlers[] = { |
2d2f2d73 MS |
1058 | &ovl_own_trusted_xattr_handler, |
1059 | &ovl_other_xattr_handler, | |
1060 | NULL | |
1061 | }; | |
1062 | ||
1063 | static const struct xattr_handler *ovl_user_xattr_handlers[] = { | |
2d2f2d73 | 1064 | &ovl_own_user_xattr_handler, |
d837a49b MS |
1065 | &ovl_other_xattr_handler, |
1066 | NULL | |
1067 | }; | |
1068 | ||
146d62e5 AG |
1069 | static int ovl_setup_trap(struct super_block *sb, struct dentry *dir, |
1070 | struct inode **ptrap, const char *name) | |
1071 | { | |
1072 | struct inode *trap; | |
1073 | int err; | |
1074 | ||
1075 | trap = ovl_get_trap_inode(sb, dir); | |
1dac6f5b AB |
1076 | err = PTR_ERR_OR_ZERO(trap); |
1077 | if (err) { | |
146d62e5 | 1078 | if (err == -ELOOP) |
1bd0a3ae | 1079 | pr_err("conflicting %s path\n", name); |
146d62e5 AG |
1080 | return err; |
1081 | } | |
1082 | ||
1083 | *ptrap = trap; | |
1084 | return 0; | |
1085 | } | |
1086 | ||
0be0bfd2 AG |
1087 | /* |
1088 | * Determine how we treat concurrent use of upperdir/workdir based on the | |
1089 | * index feature. This is papering over mount leaks of container runtimes, | |
1090 | * for example, an old overlay mount is leaked and now its upperdir is | |
1091 | * attempted to be used as a lower layer in a new overlay mount. | |
1092 | */ | |
1093 | static int ovl_report_in_use(struct ovl_fs *ofs, const char *name) | |
1094 | { | |
1095 | if (ofs->config.index) { | |
1bd0a3ae | 1096 | pr_err("%s is in-use as upperdir/workdir of another mount, mount with '-o index=off' to override exclusive upperdir protection.\n", |
0be0bfd2 AG |
1097 | name); |
1098 | return -EBUSY; | |
1099 | } else { | |
1bd0a3ae | 1100 | pr_warn("%s is in-use as upperdir/workdir of another mount, accessing files from both mounts will result in undefined behavior.\n", |
0be0bfd2 AG |
1101 | name); |
1102 | return 0; | |
1103 | } | |
1104 | } | |
1105 | ||
146d62e5 | 1106 | static int ovl_get_upper(struct super_block *sb, struct ovl_fs *ofs, |
b8e42a65 | 1107 | struct ovl_layer *upper_layer, struct path *upperpath) |
6ee8acf0 | 1108 | { |
5064975e | 1109 | struct vfsmount *upper_mnt; |
6ee8acf0 MS |
1110 | int err; |
1111 | ||
ad204488 | 1112 | err = ovl_mount_dir(ofs->config.upperdir, upperpath); |
6ee8acf0 MS |
1113 | if (err) |
1114 | goto out; | |
1115 | ||
e21a6c57 AG |
1116 | /* Upperdir path should not be r/o */ |
1117 | if (__mnt_is_readonly(upperpath->mnt)) { | |
1bd0a3ae | 1118 | pr_err("upper fs is r/o, try multi-lower layers mount\n"); |
6ee8acf0 MS |
1119 | err = -EINVAL; |
1120 | goto out; | |
1121 | } | |
1122 | ||
ad204488 | 1123 | err = ovl_check_namelen(upperpath, ofs, ofs->config.upperdir); |
6ee8acf0 MS |
1124 | if (err) |
1125 | goto out; | |
1126 | ||
b8e42a65 | 1127 | err = ovl_setup_trap(sb, upperpath->dentry, &upper_layer->trap, |
146d62e5 AG |
1128 | "upperdir"); |
1129 | if (err) | |
1130 | goto out; | |
1131 | ||
5064975e MS |
1132 | upper_mnt = clone_private_mount(upperpath); |
1133 | err = PTR_ERR(upper_mnt); | |
1134 | if (IS_ERR(upper_mnt)) { | |
1bd0a3ae | 1135 | pr_err("failed to clone upperpath\n"); |
5064975e MS |
1136 | goto out; |
1137 | } | |
1138 | ||
1139 | /* Don't inherit atime flags */ | |
1140 | upper_mnt->mnt_flags &= ~(MNT_NOATIME | MNT_NODIRATIME | MNT_RELATIME); | |
b8e42a65 MS |
1141 | upper_layer->mnt = upper_mnt; |
1142 | upper_layer->idx = 0; | |
1143 | upper_layer->fsid = 0; | |
8c25741a | 1144 | |
654255fa JX |
1145 | /* |
1146 | * Inherit SB_NOSEC flag from upperdir. | |
1147 | * | |
1148 | * This optimization changes behavior when a security related attribute | |
1149 | * (suid/sgid/security.*) is changed on an underlying layer. This is | |
1150 | * okay because we don't yet have guarantees in that case, but it will | |
1151 | * need careful treatment once we want to honour changes to underlying | |
1152 | * filesystems. | |
1153 | */ | |
1154 | if (upper_mnt->mnt_sb->s_flags & SB_NOSEC) | |
1155 | sb->s_flags |= SB_NOSEC; | |
1156 | ||
08f4c7c8 | 1157 | if (ovl_inuse_trylock(ovl_upper_mnt(ofs)->mnt_root)) { |
8c25741a | 1158 | ofs->upperdir_locked = true; |
8c25741a | 1159 | } else { |
0be0bfd2 AG |
1160 | err = ovl_report_in_use(ofs, "upperdir"); |
1161 | if (err) | |
1162 | goto out; | |
8c25741a MS |
1163 | } |
1164 | ||
6ee8acf0 MS |
1165 | err = 0; |
1166 | out: | |
1167 | return err; | |
1168 | } | |
1169 | ||
cad218ab AG |
1170 | /* |
1171 | * Returns 1 if RENAME_WHITEOUT is supported, 0 if not supported and | |
1172 | * negative values if error is encountered. | |
1173 | */ | |
576bb263 | 1174 | static int ovl_check_rename_whiteout(struct ovl_fs *ofs) |
cad218ab | 1175 | { |
576bb263 | 1176 | struct dentry *workdir = ofs->workdir; |
cad218ab AG |
1177 | struct inode *dir = d_inode(workdir); |
1178 | struct dentry *temp; | |
1179 | struct dentry *dest; | |
1180 | struct dentry *whiteout; | |
1181 | struct name_snapshot name; | |
1182 | int err; | |
1183 | ||
1184 | inode_lock_nested(dir, I_MUTEX_PARENT); | |
1185 | ||
576bb263 | 1186 | temp = ovl_create_temp(ofs, workdir, OVL_CATTR(S_IFREG | 0)); |
cad218ab AG |
1187 | err = PTR_ERR(temp); |
1188 | if (IS_ERR(temp)) | |
1189 | goto out_unlock; | |
1190 | ||
576bb263 | 1191 | dest = ovl_lookup_temp(ofs, workdir); |
cad218ab AG |
1192 | err = PTR_ERR(dest); |
1193 | if (IS_ERR(dest)) { | |
1194 | dput(temp); | |
1195 | goto out_unlock; | |
1196 | } | |
1197 | ||
1198 | /* Name is inline and stable - using snapshot as a copy helper */ | |
1199 | take_dentry_name_snapshot(&name, temp); | |
576bb263 | 1200 | err = ovl_do_rename(ofs, dir, temp, dir, dest, RENAME_WHITEOUT); |
cad218ab AG |
1201 | if (err) { |
1202 | if (err == -EINVAL) | |
1203 | err = 0; | |
1204 | goto cleanup_temp; | |
1205 | } | |
1206 | ||
22f289ce | 1207 | whiteout = ovl_lookup_upper(ofs, name.name.name, workdir, name.name.len); |
cad218ab AG |
1208 | err = PTR_ERR(whiteout); |
1209 | if (IS_ERR(whiteout)) | |
1210 | goto cleanup_temp; | |
1211 | ||
1212 | err = ovl_is_whiteout(whiteout); | |
1213 | ||
1214 | /* Best effort cleanup of whiteout and temp file */ | |
1215 | if (err) | |
576bb263 | 1216 | ovl_cleanup(ofs, dir, whiteout); |
cad218ab AG |
1217 | dput(whiteout); |
1218 | ||
1219 | cleanup_temp: | |
576bb263 | 1220 | ovl_cleanup(ofs, dir, temp); |
cad218ab AG |
1221 | release_dentry_name_snapshot(&name); |
1222 | dput(temp); | |
1223 | dput(dest); | |
1224 | ||
1225 | out_unlock: | |
1226 | inode_unlock(dir); | |
1227 | ||
1228 | return err; | |
1229 | } | |
1230 | ||
576bb263 CB |
1231 | static struct dentry *ovl_lookup_or_create(struct ovl_fs *ofs, |
1232 | struct dentry *parent, | |
c86243b0 VG |
1233 | const char *name, umode_t mode) |
1234 | { | |
1235 | size_t len = strlen(name); | |
1236 | struct dentry *child; | |
1237 | ||
1238 | inode_lock_nested(parent->d_inode, I_MUTEX_PARENT); | |
22f289ce | 1239 | child = ovl_lookup_upper(ofs, name, parent, len); |
c86243b0 | 1240 | if (!IS_ERR(child) && !child->d_inode) |
576bb263 | 1241 | child = ovl_create_real(ofs, parent->d_inode, child, |
c86243b0 VG |
1242 | OVL_CATTR(mode)); |
1243 | inode_unlock(parent->d_inode); | |
1244 | dput(parent); | |
1245 | ||
1246 | return child; | |
1247 | } | |
1248 | ||
1249 | /* | |
1250 | * Creates $workdir/work/incompat/volatile/dirty file if it is not already | |
1251 | * present. | |
1252 | */ | |
1253 | static int ovl_create_volatile_dirty(struct ovl_fs *ofs) | |
1254 | { | |
1255 | unsigned int ctr; | |
1256 | struct dentry *d = dget(ofs->workbasedir); | |
1257 | static const char *const volatile_path[] = { | |
1258 | OVL_WORKDIR_NAME, "incompat", "volatile", "dirty" | |
1259 | }; | |
1260 | const char *const *name = volatile_path; | |
1261 | ||
1262 | for (ctr = ARRAY_SIZE(volatile_path); ctr; ctr--, name++) { | |
576bb263 | 1263 | d = ovl_lookup_or_create(ofs, d, *name, ctr > 1 ? S_IFDIR : S_IFREG); |
c86243b0 VG |
1264 | if (IS_ERR(d)) |
1265 | return PTR_ERR(d); | |
1266 | } | |
1267 | dput(d); | |
1268 | return 0; | |
1269 | } | |
1270 | ||
146d62e5 | 1271 | static int ovl_make_workdir(struct super_block *sb, struct ovl_fs *ofs, |
2d343087 | 1272 | const struct path *workpath) |
8ed61dc3 | 1273 | { |
08f4c7c8 | 1274 | struct vfsmount *mnt = ovl_upper_mnt(ofs); |
2b1a7746 MS |
1275 | struct dentry *workdir; |
1276 | struct file *tmpfile; | |
d80172c2 AG |
1277 | bool rename_whiteout; |
1278 | bool d_type; | |
e487d889 | 1279 | int fh_type; |
8ed61dc3 MS |
1280 | int err; |
1281 | ||
2ba9d57e AG |
1282 | err = mnt_want_write(mnt); |
1283 | if (err) | |
1284 | return err; | |
1285 | ||
235ce9ed AG |
1286 | workdir = ovl_workdir_create(ofs, OVL_WORKDIR_NAME, false); |
1287 | err = PTR_ERR(workdir); | |
1288 | if (IS_ERR_OR_NULL(workdir)) | |
2ba9d57e | 1289 | goto out; |
8ed61dc3 | 1290 | |
235ce9ed AG |
1291 | ofs->workdir = workdir; |
1292 | ||
146d62e5 AG |
1293 | err = ovl_setup_trap(sb, ofs->workdir, &ofs->workdir_trap, "workdir"); |
1294 | if (err) | |
1295 | goto out; | |
1296 | ||
8ed61dc3 MS |
1297 | /* |
1298 | * Upper should support d_type, else whiteouts are visible. Given | |
1299 | * workdir and upper are on same fs, we can do iterate_dir() on | |
1300 | * workdir. This check requires successful creation of workdir in | |
1301 | * previous step. | |
1302 | */ | |
1303 | err = ovl_check_d_type_supported(workpath); | |
1304 | if (err < 0) | |
2ba9d57e | 1305 | goto out; |
8ed61dc3 | 1306 | |
d80172c2 AG |
1307 | d_type = err; |
1308 | if (!d_type) | |
1bd0a3ae | 1309 | pr_warn("upper fs needs to support d_type.\n"); |
8ed61dc3 MS |
1310 | |
1311 | /* Check if upper/work fs supports O_TMPFILE */ | |
2b1a7746 MS |
1312 | tmpfile = ovl_do_tmpfile(ofs, ofs->workdir, S_IFREG | 0); |
1313 | ofs->tmpfile = !IS_ERR(tmpfile); | |
ad204488 | 1314 | if (ofs->tmpfile) |
2b1a7746 | 1315 | fput(tmpfile); |
8ed61dc3 | 1316 | else |
1bd0a3ae | 1317 | pr_warn("upper fs does not support tmpfile.\n"); |
8ed61dc3 | 1318 | |
cad218ab AG |
1319 | |
1320 | /* Check if upper/work fs supports RENAME_WHITEOUT */ | |
576bb263 | 1321 | err = ovl_check_rename_whiteout(ofs); |
cad218ab AG |
1322 | if (err < 0) |
1323 | goto out; | |
1324 | ||
d80172c2 AG |
1325 | rename_whiteout = err; |
1326 | if (!rename_whiteout) | |
cad218ab AG |
1327 | pr_warn("upper fs does not support RENAME_WHITEOUT.\n"); |
1328 | ||
8ed61dc3 | 1329 | /* |
2d2f2d73 | 1330 | * Check if upper/work fs supports (trusted|user).overlay.* xattr |
8ed61dc3 | 1331 | */ |
c914c0e2 | 1332 | err = ovl_setxattr(ofs, ofs->workdir, OVL_XATTR_OPAQUE, "0", 1); |
8ed61dc3 | 1333 | if (err) { |
b10b85fe | 1334 | pr_warn("failed to set xattr on upper\n"); |
ad204488 | 1335 | ofs->noxattr = true; |
b0e0f697 AG |
1336 | if (ofs->config.index || ofs->config.metacopy) { |
1337 | ofs->config.index = false; | |
1338 | ofs->config.metacopy = false; | |
b10b85fe | 1339 | pr_warn("...falling back to index=off,metacopy=off.\n"); |
b0e0f697 AG |
1340 | } |
1341 | /* | |
1342 | * xattr support is required for persistent st_ino. | |
1343 | * Without persistent st_ino, xino=auto falls back to xino=off. | |
1344 | */ | |
1345 | if (ofs->config.xino == OVL_XINO_AUTO) { | |
1346 | ofs->config.xino = OVL_XINO_OFF; | |
b10b85fe | 1347 | pr_warn("...falling back to xino=off.\n"); |
b0e0f697 | 1348 | } |
b10b85fe MS |
1349 | if (err == -EPERM && !ofs->config.userxattr) |
1350 | pr_info("try mounting with 'userxattr' option\n"); | |
2ba9d57e | 1351 | err = 0; |
8ed61dc3 | 1352 | } else { |
c914c0e2 | 1353 | ovl_removexattr(ofs, ofs->workdir, OVL_XATTR_OPAQUE); |
8ed61dc3 MS |
1354 | } |
1355 | ||
d80172c2 AG |
1356 | /* |
1357 | * We allowed sub-optimal upper fs configuration and don't want to break | |
1358 | * users over kernel upgrade, but we never allowed remote upper fs, so | |
1359 | * we can enforce strict requirements for remote upper fs. | |
1360 | */ | |
1361 | if (ovl_dentry_remote(ofs->workdir) && | |
1362 | (!d_type || !rename_whiteout || ofs->noxattr)) { | |
1363 | pr_err("upper fs missing required features.\n"); | |
1364 | err = -EINVAL; | |
1365 | goto out; | |
1366 | } | |
1367 | ||
c86243b0 VG |
1368 | /* |
1369 | * For volatile mount, create a incompat/volatile/dirty file to keep | |
1370 | * track of it. | |
1371 | */ | |
1372 | if (ofs->config.ovl_volatile) { | |
1373 | err = ovl_create_volatile_dirty(ofs); | |
1374 | if (err < 0) { | |
1375 | pr_err("Failed to create volatile/dirty file.\n"); | |
1376 | goto out; | |
1377 | } | |
1378 | } | |
1379 | ||
8ed61dc3 | 1380 | /* Check if upper/work fs supports file handles */ |
e487d889 AG |
1381 | fh_type = ovl_can_decode_fh(ofs->workdir->d_sb); |
1382 | if (ofs->config.index && !fh_type) { | |
ad204488 | 1383 | ofs->config.index = false; |
1bd0a3ae | 1384 | pr_warn("upper fs does not support file handles, falling back to index=off.\n"); |
8ed61dc3 MS |
1385 | } |
1386 | ||
e487d889 AG |
1387 | /* Check if upper fs has 32bit inode numbers */ |
1388 | if (fh_type != FILEID_INO32_GEN) | |
0f831ec8 | 1389 | ofs->xino_mode = -1; |
e487d889 | 1390 | |
f168f109 AG |
1391 | /* NFS export of r/w mount depends on index */ |
1392 | if (ofs->config.nfs_export && !ofs->config.index) { | |
1bd0a3ae | 1393 | pr_warn("NFS export requires \"index=on\", falling back to nfs_export=off.\n"); |
f168f109 AG |
1394 | ofs->config.nfs_export = false; |
1395 | } | |
2ba9d57e AG |
1396 | out: |
1397 | mnt_drop_write(mnt); | |
1398 | return err; | |
8ed61dc3 MS |
1399 | } |
1400 | ||
146d62e5 | 1401 | static int ovl_get_workdir(struct super_block *sb, struct ovl_fs *ofs, |
2d343087 | 1402 | const struct path *upperpath) |
520d7c86 MS |
1403 | { |
1404 | int err; | |
bca44b52 | 1405 | struct path workpath = { }; |
520d7c86 | 1406 | |
ad204488 | 1407 | err = ovl_mount_dir(ofs->config.workdir, &workpath); |
520d7c86 MS |
1408 | if (err) |
1409 | goto out; | |
1410 | ||
1411 | err = -EINVAL; | |
bca44b52 | 1412 | if (upperpath->mnt != workpath.mnt) { |
1bd0a3ae | 1413 | pr_err("workdir and upperdir must reside under the same mount\n"); |
520d7c86 MS |
1414 | goto out; |
1415 | } | |
bca44b52 | 1416 | if (!ovl_workdir_ok(workpath.dentry, upperpath->dentry)) { |
1bd0a3ae | 1417 | pr_err("workdir and upperdir must be separate subtrees\n"); |
520d7c86 MS |
1418 | goto out; |
1419 | } | |
1420 | ||
8c25741a MS |
1421 | ofs->workbasedir = dget(workpath.dentry); |
1422 | ||
8c25741a | 1423 | if (ovl_inuse_trylock(ofs->workbasedir)) { |
ad204488 | 1424 | ofs->workdir_locked = true; |
520d7c86 | 1425 | } else { |
0be0bfd2 AG |
1426 | err = ovl_report_in_use(ofs, "workdir"); |
1427 | if (err) | |
1428 | goto out; | |
520d7c86 MS |
1429 | } |
1430 | ||
0be0bfd2 AG |
1431 | err = ovl_setup_trap(sb, ofs->workbasedir, &ofs->workbasedir_trap, |
1432 | "workdir"); | |
1433 | if (err) | |
1434 | goto out; | |
1435 | ||
146d62e5 | 1436 | err = ovl_make_workdir(sb, ofs, &workpath); |
bca44b52 | 1437 | |
520d7c86 | 1438 | out: |
bca44b52 MS |
1439 | path_put(&workpath); |
1440 | ||
520d7c86 MS |
1441 | return err; |
1442 | } | |
1443 | ||
146d62e5 | 1444 | static int ovl_get_indexdir(struct super_block *sb, struct ovl_fs *ofs, |
2d343087 | 1445 | struct ovl_entry *oe, const struct path *upperpath) |
f7e3a7d9 | 1446 | { |
08f4c7c8 | 1447 | struct vfsmount *mnt = ovl_upper_mnt(ofs); |
235ce9ed | 1448 | struct dentry *indexdir; |
f7e3a7d9 MS |
1449 | int err; |
1450 | ||
2ba9d57e AG |
1451 | err = mnt_want_write(mnt); |
1452 | if (err) | |
1453 | return err; | |
1454 | ||
f7e3a7d9 | 1455 | /* Verify lower root is upper root origin */ |
610afc0b MS |
1456 | err = ovl_verify_origin(ofs, upperpath->dentry, |
1457 | oe->lowerstack[0].dentry, true); | |
f7e3a7d9 | 1458 | if (err) { |
1bd0a3ae | 1459 | pr_err("failed to verify upper root origin\n"); |
f7e3a7d9 MS |
1460 | goto out; |
1461 | } | |
1462 | ||
470c1563 AG |
1463 | /* index dir will act also as workdir */ |
1464 | iput(ofs->workdir_trap); | |
1465 | ofs->workdir_trap = NULL; | |
1466 | dput(ofs->workdir); | |
1467 | ofs->workdir = NULL; | |
235ce9ed AG |
1468 | indexdir = ovl_workdir_create(ofs, OVL_INDEXDIR_NAME, true); |
1469 | if (IS_ERR(indexdir)) { | |
1470 | err = PTR_ERR(indexdir); | |
1471 | } else if (indexdir) { | |
1472 | ofs->indexdir = indexdir; | |
1473 | ofs->workdir = dget(indexdir); | |
20396365 | 1474 | |
146d62e5 AG |
1475 | err = ovl_setup_trap(sb, ofs->indexdir, &ofs->indexdir_trap, |
1476 | "indexdir"); | |
1477 | if (err) | |
1478 | goto out; | |
1479 | ||
ad1d615c AG |
1480 | /* |
1481 | * Verify upper root is exclusively associated with index dir. | |
2d2f2d73 | 1482 | * Older kernels stored upper fh in ".overlay.origin" |
ad1d615c AG |
1483 | * xattr. If that xattr exists, verify that it is a match to |
1484 | * upper dir file handle. In any case, verify or set xattr | |
2d2f2d73 | 1485 | * ".overlay.upper" to indicate that index may have |
ad1d615c AG |
1486 | * directory entries. |
1487 | */ | |
610afc0b MS |
1488 | if (ovl_check_origin_xattr(ofs, ofs->indexdir)) { |
1489 | err = ovl_verify_set_fh(ofs, ofs->indexdir, | |
1490 | OVL_XATTR_ORIGIN, | |
ad1d615c AG |
1491 | upperpath->dentry, true, false); |
1492 | if (err) | |
1bd0a3ae | 1493 | pr_err("failed to verify index dir 'origin' xattr\n"); |
ad1d615c | 1494 | } |
610afc0b MS |
1495 | err = ovl_verify_upper(ofs, ofs->indexdir, upperpath->dentry, |
1496 | true); | |
f7e3a7d9 | 1497 | if (err) |
1bd0a3ae | 1498 | pr_err("failed to verify index dir 'upper' xattr\n"); |
f7e3a7d9 MS |
1499 | |
1500 | /* Cleanup bad/stale/orphan index entries */ | |
1501 | if (!err) | |
1eff1a1d | 1502 | err = ovl_indexdir_cleanup(ofs); |
f7e3a7d9 | 1503 | } |
ad204488 | 1504 | if (err || !ofs->indexdir) |
1bd0a3ae | 1505 | pr_warn("try deleting index dir or mounting with '-o index=off' to disable inodes index.\n"); |
f7e3a7d9 MS |
1506 | |
1507 | out: | |
2ba9d57e | 1508 | mnt_drop_write(mnt); |
f7e3a7d9 MS |
1509 | return err; |
1510 | } | |
1511 | ||
9df085f3 AG |
1512 | static bool ovl_lower_uuid_ok(struct ovl_fs *ofs, const uuid_t *uuid) |
1513 | { | |
1514 | unsigned int i; | |
1515 | ||
08f4c7c8 | 1516 | if (!ofs->config.nfs_export && !ovl_upper_mnt(ofs)) |
9df085f3 AG |
1517 | return true; |
1518 | ||
a888db31 AG |
1519 | /* |
1520 | * We allow using single lower with null uuid for index and nfs_export | |
1521 | * for example to support those features with single lower squashfs. | |
1522 | * To avoid regressions in setups of overlay with re-formatted lower | |
1523 | * squashfs, do not allow decoding origin with lower null uuid unless | |
1524 | * user opted-in to one of the new features that require following the | |
1525 | * lower inode of non-dir upper. | |
1526 | */ | |
ca45275c | 1527 | if (ovl_allow_offline_changes(ofs) && uuid_is_null(uuid)) |
a888db31 AG |
1528 | return false; |
1529 | ||
1b81dddd | 1530 | for (i = 0; i < ofs->numfs; i++) { |
9df085f3 AG |
1531 | /* |
1532 | * We use uuid to associate an overlay lower file handle with a | |
1533 | * lower layer, so we can accept lower fs with null uuid as long | |
1534 | * as all lower layers with null uuid are on the same fs. | |
7e63c87f AG |
1535 | * if we detect multiple lower fs with the same uuid, we |
1536 | * disable lower file handle decoding on all of them. | |
9df085f3 | 1537 | */ |
1b81dddd AG |
1538 | if (ofs->fs[i].is_lower && |
1539 | uuid_equal(&ofs->fs[i].sb->s_uuid, uuid)) { | |
07f1e596 | 1540 | ofs->fs[i].bad_uuid = true; |
9df085f3 | 1541 | return false; |
7e63c87f | 1542 | } |
9df085f3 AG |
1543 | } |
1544 | return true; | |
1545 | } | |
1546 | ||
5148626b | 1547 | /* Get a unique fsid for the layer */ |
9df085f3 | 1548 | static int ovl_get_fsid(struct ovl_fs *ofs, const struct path *path) |
5148626b | 1549 | { |
9df085f3 | 1550 | struct super_block *sb = path->mnt->mnt_sb; |
5148626b AG |
1551 | unsigned int i; |
1552 | dev_t dev; | |
1553 | int err; | |
7e63c87f | 1554 | bool bad_uuid = false; |
b0e0f697 | 1555 | bool warn = false; |
5148626b | 1556 | |
07f1e596 AG |
1557 | for (i = 0; i < ofs->numfs; i++) { |
1558 | if (ofs->fs[i].sb == sb) | |
1559 | return i; | |
5148626b AG |
1560 | } |
1561 | ||
9df085f3 | 1562 | if (!ovl_lower_uuid_ok(ofs, &sb->s_uuid)) { |
7e63c87f | 1563 | bad_uuid = true; |
b0e0f697 AG |
1564 | if (ofs->config.xino == OVL_XINO_AUTO) { |
1565 | ofs->config.xino = OVL_XINO_OFF; | |
1566 | warn = true; | |
1567 | } | |
7e63c87f AG |
1568 | if (ofs->config.index || ofs->config.nfs_export) { |
1569 | ofs->config.index = false; | |
1570 | ofs->config.nfs_export = false; | |
b0e0f697 AG |
1571 | warn = true; |
1572 | } | |
1573 | if (warn) { | |
1574 | pr_warn("%s uuid detected in lower fs '%pd2', falling back to xino=%s,index=off,nfs_export=off.\n", | |
7e63c87f AG |
1575 | uuid_is_null(&sb->s_uuid) ? "null" : |
1576 | "conflicting", | |
b0e0f697 | 1577 | path->dentry, ovl_xino_str[ofs->config.xino]); |
7e63c87f | 1578 | } |
9df085f3 AG |
1579 | } |
1580 | ||
5148626b AG |
1581 | err = get_anon_bdev(&dev); |
1582 | if (err) { | |
1bd0a3ae | 1583 | pr_err("failed to get anonymous bdev for lowerpath\n"); |
5148626b AG |
1584 | return err; |
1585 | } | |
1586 | ||
07f1e596 AG |
1587 | ofs->fs[ofs->numfs].sb = sb; |
1588 | ofs->fs[ofs->numfs].pseudo_dev = dev; | |
1589 | ofs->fs[ofs->numfs].bad_uuid = bad_uuid; | |
5148626b | 1590 | |
07f1e596 | 1591 | return ofs->numfs++; |
5148626b AG |
1592 | } |
1593 | ||
94375f9d | 1594 | static int ovl_get_layers(struct super_block *sb, struct ovl_fs *ofs, |
b8e42a65 MS |
1595 | struct path *stack, unsigned int numlower, |
1596 | struct ovl_layer *layers) | |
520d7c86 MS |
1597 | { |
1598 | int err; | |
1599 | unsigned int i; | |
1600 | ||
1601 | err = -ENOMEM; | |
07f1e596 AG |
1602 | ofs->fs = kcalloc(numlower + 1, sizeof(struct ovl_sb), GFP_KERNEL); |
1603 | if (ofs->fs == NULL) | |
5148626b AG |
1604 | goto out; |
1605 | ||
07f1e596 AG |
1606 | /* idx/fsid 0 are reserved for upper fs even with lower only overlay */ |
1607 | ofs->numfs++; | |
1608 | ||
07f1e596 | 1609 | /* |
b7bf9908 AG |
1610 | * All lower layers that share the same fs as upper layer, use the same |
1611 | * pseudo_dev as upper layer. Allocate fs[0].pseudo_dev even for lower | |
1612 | * only overlay to simplify ovl_fs_free(). | |
1b81dddd | 1613 | * is_lower will be set if upper fs is shared with a lower layer. |
07f1e596 | 1614 | */ |
b7bf9908 AG |
1615 | err = get_anon_bdev(&ofs->fs[0].pseudo_dev); |
1616 | if (err) { | |
1617 | pr_err("failed to get anonymous bdev for upper fs\n"); | |
1618 | goto out; | |
1619 | } | |
1620 | ||
08f4c7c8 MS |
1621 | if (ovl_upper_mnt(ofs)) { |
1622 | ofs->fs[0].sb = ovl_upper_mnt(ofs)->mnt_sb; | |
1b81dddd | 1623 | ofs->fs[0].is_lower = false; |
07f1e596 AG |
1624 | } |
1625 | ||
520d7c86 MS |
1626 | for (i = 0; i < numlower; i++) { |
1627 | struct vfsmount *mnt; | |
146d62e5 | 1628 | struct inode *trap; |
5148626b | 1629 | int fsid; |
520d7c86 | 1630 | |
9df085f3 | 1631 | err = fsid = ovl_get_fsid(ofs, &stack[i]); |
5148626b | 1632 | if (err < 0) |
520d7c86 | 1633 | goto out; |
520d7c86 | 1634 | |
24f14009 | 1635 | /* |
1636 | * Check if lower root conflicts with this overlay layers before | |
1637 | * checking if it is in-use as upperdir/workdir of "another" | |
1638 | * mount, because we do not bother to check in ovl_is_inuse() if | |
1639 | * the upperdir/workdir is in fact in-use by our | |
1640 | * upperdir/workdir. | |
1641 | */ | |
146d62e5 AG |
1642 | err = ovl_setup_trap(sb, stack[i].dentry, &trap, "lowerdir"); |
1643 | if (err) | |
1644 | goto out; | |
1645 | ||
0be0bfd2 AG |
1646 | if (ovl_is_inuse(stack[i].dentry)) { |
1647 | err = ovl_report_in_use(ofs, "lowerdir"); | |
24f14009 | 1648 | if (err) { |
1649 | iput(trap); | |
0be0bfd2 | 1650 | goto out; |
24f14009 | 1651 | } |
0be0bfd2 AG |
1652 | } |
1653 | ||
520d7c86 MS |
1654 | mnt = clone_private_mount(&stack[i]); |
1655 | err = PTR_ERR(mnt); | |
1656 | if (IS_ERR(mnt)) { | |
1bd0a3ae | 1657 | pr_err("failed to clone lowerpath\n"); |
146d62e5 | 1658 | iput(trap); |
520d7c86 MS |
1659 | goto out; |
1660 | } | |
5148626b | 1661 | |
520d7c86 MS |
1662 | /* |
1663 | * Make lower layers R/O. That way fchmod/fchown on lower file | |
1664 | * will fail instead of modifying lower fs. | |
1665 | */ | |
1666 | mnt->mnt_flags |= MNT_READONLY | MNT_NOATIME; | |
1667 | ||
13464165 MS |
1668 | layers[ofs->numlayer].trap = trap; |
1669 | layers[ofs->numlayer].mnt = mnt; | |
1670 | layers[ofs->numlayer].idx = ofs->numlayer; | |
1671 | layers[ofs->numlayer].fsid = fsid; | |
1672 | layers[ofs->numlayer].fs = &ofs->fs[fsid]; | |
94375f9d | 1673 | ofs->numlayer++; |
1b81dddd | 1674 | ofs->fs[fsid].is_lower = true; |
520d7c86 | 1675 | } |
e487d889 | 1676 | |
795939a9 AG |
1677 | /* |
1678 | * When all layers on same fs, overlay can use real inode numbers. | |
926e94d7 AG |
1679 | * With mount option "xino=<on|auto>", mounter declares that there are |
1680 | * enough free high bits in underlying fs to hold the unique fsid. | |
795939a9 AG |
1681 | * If overlayfs does encounter underlying inodes using the high xino |
1682 | * bits reserved for fsid, it emits a warning and uses the original | |
dfe51d47 AG |
1683 | * inode number or a non persistent inode number allocated from a |
1684 | * dedicated range. | |
795939a9 | 1685 | */ |
08f4c7c8 | 1686 | if (ofs->numfs - !ovl_upper_mnt(ofs) == 1) { |
0f831ec8 AG |
1687 | if (ofs->config.xino == OVL_XINO_ON) |
1688 | pr_info("\"xino=on\" is useless with all layers on same fs, ignore.\n"); | |
1689 | ofs->xino_mode = 0; | |
53afcd31 AG |
1690 | } else if (ofs->config.xino == OVL_XINO_OFF) { |
1691 | ofs->xino_mode = -1; | |
926e94d7 | 1692 | } else if (ofs->xino_mode < 0) { |
795939a9 | 1693 | /* |
07f1e596 | 1694 | * This is a roundup of number of bits needed for encoding |
dfe51d47 AG |
1695 | * fsid, where fsid 0 is reserved for upper fs (even with |
1696 | * lower only overlay) +1 extra bit is reserved for the non | |
1697 | * persistent inode number range that is used for resolving | |
1698 | * xino lower bits overflow. | |
795939a9 | 1699 | */ |
dfe51d47 AG |
1700 | BUILD_BUG_ON(ilog2(OVL_MAX_STACK) > 30); |
1701 | ofs->xino_mode = ilog2(ofs->numfs - 1) + 2; | |
795939a9 AG |
1702 | } |
1703 | ||
0f831ec8 | 1704 | if (ofs->xino_mode > 0) { |
1bd0a3ae | 1705 | pr_info("\"xino\" feature enabled using %d upper inode bits.\n", |
0f831ec8 | 1706 | ofs->xino_mode); |
795939a9 | 1707 | } |
e487d889 | 1708 | |
520d7c86 MS |
1709 | err = 0; |
1710 | out: | |
1711 | return err; | |
1712 | } | |
1713 | ||
4155c10a | 1714 | static struct ovl_entry *ovl_get_lowerstack(struct super_block *sb, |
b8e42a65 MS |
1715 | const char *lower, unsigned int numlower, |
1716 | struct ovl_fs *ofs, struct ovl_layer *layers) | |
53dbb0b4 MS |
1717 | { |
1718 | int err; | |
4155c10a | 1719 | struct path *stack = NULL; |
b8e42a65 | 1720 | unsigned int i; |
4155c10a | 1721 | struct ovl_entry *oe; |
53dbb0b4 | 1722 | |
b8e42a65 | 1723 | if (!ofs->config.upperdir && numlower == 1) { |
1bd0a3ae | 1724 | pr_err("at least 2 lowerdir are needed while upperdir nonexistent\n"); |
b8e42a65 | 1725 | return ERR_PTR(-EINVAL); |
53dbb0b4 MS |
1726 | } |
1727 | ||
b8e42a65 | 1728 | stack = kcalloc(numlower, sizeof(struct path), GFP_KERNEL); |
53dbb0b4 | 1729 | if (!stack) |
b8e42a65 | 1730 | return ERR_PTR(-ENOMEM); |
53dbb0b4 MS |
1731 | |
1732 | err = -EINVAL; | |
b8e42a65 MS |
1733 | for (i = 0; i < numlower; i++) { |
1734 | err = ovl_lower_dir(lower, &stack[i], ofs, &sb->s_stack_depth); | |
53dbb0b4 | 1735 | if (err) |
4155c10a | 1736 | goto out_err; |
53dbb0b4 MS |
1737 | |
1738 | lower = strchr(lower, '\0') + 1; | |
1739 | } | |
1740 | ||
1741 | err = -EINVAL; | |
1742 | sb->s_stack_depth++; | |
1743 | if (sb->s_stack_depth > FILESYSTEM_MAX_STACK_DEPTH) { | |
1bd0a3ae | 1744 | pr_err("maximum fs stacking depth exceeded\n"); |
4155c10a | 1745 | goto out_err; |
53dbb0b4 MS |
1746 | } |
1747 | ||
b8e42a65 | 1748 | err = ovl_get_layers(sb, ofs, stack, numlower, layers); |
4155c10a MS |
1749 | if (err) |
1750 | goto out_err; | |
1751 | ||
1752 | err = -ENOMEM; | |
1753 | oe = ovl_alloc_entry(numlower); | |
1754 | if (!oe) | |
1755 | goto out_err; | |
1756 | ||
1757 | for (i = 0; i < numlower; i++) { | |
1758 | oe->lowerstack[i].dentry = dget(stack[i].dentry); | |
94375f9d | 1759 | oe->lowerstack[i].layer = &ofs->layers[i+1]; |
4155c10a | 1760 | } |
53dbb0b4 | 1761 | |
53dbb0b4 | 1762 | out: |
53dbb0b4 MS |
1763 | for (i = 0; i < numlower; i++) |
1764 | path_put(&stack[i]); | |
1765 | kfree(stack); | |
4155c10a MS |
1766 | |
1767 | return oe; | |
1768 | ||
1769 | out_err: | |
1770 | oe = ERR_PTR(err); | |
53dbb0b4 MS |
1771 | goto out; |
1772 | } | |
1773 | ||
146d62e5 AG |
1774 | /* |
1775 | * Check if this layer root is a descendant of: | |
1776 | * - another layer of this overlayfs instance | |
1777 | * - upper/work dir of any overlayfs instance | |
146d62e5 | 1778 | */ |
0be0bfd2 | 1779 | static int ovl_check_layer(struct super_block *sb, struct ovl_fs *ofs, |
708fa015 MS |
1780 | struct dentry *dentry, const char *name, |
1781 | bool is_lower) | |
146d62e5 | 1782 | { |
9179c21d | 1783 | struct dentry *next = dentry, *parent; |
146d62e5 AG |
1784 | int err = 0; |
1785 | ||
9179c21d | 1786 | if (!dentry) |
146d62e5 AG |
1787 | return 0; |
1788 | ||
9179c21d MS |
1789 | parent = dget_parent(next); |
1790 | ||
1791 | /* Walk back ancestors to root (inclusive) looking for traps */ | |
1792 | while (!err && parent != next) { | |
708fa015 | 1793 | if (is_lower && ovl_lookup_trap_inode(sb, parent)) { |
146d62e5 | 1794 | err = -ELOOP; |
1bd0a3ae | 1795 | pr_err("overlapping %s path\n", name); |
0be0bfd2 AG |
1796 | } else if (ovl_is_inuse(parent)) { |
1797 | err = ovl_report_in_use(ofs, name); | |
146d62e5 | 1798 | } |
146d62e5 | 1799 | next = parent; |
9179c21d MS |
1800 | parent = dget_parent(next); |
1801 | dput(next); | |
146d62e5 AG |
1802 | } |
1803 | ||
9179c21d | 1804 | dput(parent); |
146d62e5 AG |
1805 | |
1806 | return err; | |
1807 | } | |
1808 | ||
1809 | /* | |
1810 | * Check if any of the layers or work dirs overlap. | |
1811 | */ | |
1812 | static int ovl_check_overlapping_layers(struct super_block *sb, | |
1813 | struct ovl_fs *ofs) | |
1814 | { | |
1815 | int i, err; | |
1816 | ||
08f4c7c8 MS |
1817 | if (ovl_upper_mnt(ofs)) { |
1818 | err = ovl_check_layer(sb, ofs, ovl_upper_mnt(ofs)->mnt_root, | |
708fa015 | 1819 | "upperdir", false); |
146d62e5 AG |
1820 | if (err) |
1821 | return err; | |
1822 | ||
1823 | /* | |
1824 | * Checking workbasedir avoids hitting ovl_is_inuse(parent) of | |
1825 | * this instance and covers overlapping work and index dirs, | |
1826 | * unless work or index dir have been moved since created inside | |
1827 | * workbasedir. In that case, we already have their traps in | |
1828 | * inode cache and we will catch that case on lookup. | |
1829 | */ | |
708fa015 MS |
1830 | err = ovl_check_layer(sb, ofs, ofs->workbasedir, "workdir", |
1831 | false); | |
146d62e5 AG |
1832 | if (err) |
1833 | return err; | |
1834 | } | |
1835 | ||
94375f9d | 1836 | for (i = 1; i < ofs->numlayer; i++) { |
0be0bfd2 | 1837 | err = ovl_check_layer(sb, ofs, |
94375f9d | 1838 | ofs->layers[i].mnt->mnt_root, |
708fa015 | 1839 | "lowerdir", true); |
146d62e5 AG |
1840 | if (err) |
1841 | return err; | |
1842 | } | |
1843 | ||
1844 | return 0; | |
1845 | } | |
1846 | ||
2effc5c2 AG |
1847 | static struct dentry *ovl_get_root(struct super_block *sb, |
1848 | struct dentry *upperdentry, | |
1849 | struct ovl_entry *oe) | |
1850 | { | |
1851 | struct dentry *root; | |
62c832ed AG |
1852 | struct ovl_path *lowerpath = &oe->lowerstack[0]; |
1853 | unsigned long ino = d_inode(lowerpath->dentry)->i_ino; | |
1854 | int fsid = lowerpath->layer->fsid; | |
1855 | struct ovl_inode_params oip = { | |
1856 | .upperdentry = upperdentry, | |
1857 | .lowerpath = lowerpath, | |
1858 | }; | |
2effc5c2 AG |
1859 | |
1860 | root = d_make_root(ovl_new_inode(sb, S_IFDIR, 0)); | |
1861 | if (!root) | |
1862 | return NULL; | |
1863 | ||
1864 | root->d_fsdata = oe; | |
1865 | ||
1866 | if (upperdentry) { | |
62c832ed AG |
1867 | /* Root inode uses upper st_ino/i_ino */ |
1868 | ino = d_inode(upperdentry)->i_ino; | |
1869 | fsid = 0; | |
2effc5c2 | 1870 | ovl_dentry_set_upper_alias(root); |
610afc0b | 1871 | if (ovl_is_impuredir(sb, upperdentry)) |
2effc5c2 AG |
1872 | ovl_set_flag(OVL_IMPURE, d_inode(root)); |
1873 | } | |
1874 | ||
1875 | /* Root is always merge -> can have whiteouts */ | |
1876 | ovl_set_flag(OVL_WHITEOUTS, d_inode(root)); | |
1877 | ovl_dentry_set_flag(OVL_E_CONNECTED, root); | |
1878 | ovl_set_upperdata(d_inode(root)); | |
62c832ed | 1879 | ovl_inode_init(d_inode(root), &oip, ino, fsid); |
f4288844 | 1880 | ovl_dentry_update_reval(root, upperdentry, DCACHE_OP_WEAK_REVALIDATE); |
2effc5c2 AG |
1881 | |
1882 | return root; | |
1883 | } | |
1884 | ||
e9be9d5e MS |
1885 | static int ovl_fill_super(struct super_block *sb, void *data, int silent) |
1886 | { | |
33006cdf | 1887 | struct path upperpath = { }; |
e9be9d5e | 1888 | struct dentry *root_dentry; |
4155c10a | 1889 | struct ovl_entry *oe; |
ad204488 | 1890 | struct ovl_fs *ofs; |
b8e42a65 | 1891 | struct ovl_layer *layers; |
51f8f3c4 | 1892 | struct cred *cred; |
b8e42a65 MS |
1893 | char *splitlower = NULL; |
1894 | unsigned int numlower; | |
e9be9d5e MS |
1895 | int err; |
1896 | ||
9efb069d MS |
1897 | err = -EIO; |
1898 | if (WARN_ON(sb->s_user_ns != current_user_ns())) | |
1899 | goto out; | |
1900 | ||
f4288844 MS |
1901 | sb->s_d_op = &ovl_dentry_operations; |
1902 | ||
f45827e8 | 1903 | err = -ENOMEM; |
ad204488 MS |
1904 | ofs = kzalloc(sizeof(struct ovl_fs), GFP_KERNEL); |
1905 | if (!ofs) | |
e9be9d5e MS |
1906 | goto out; |
1907 | ||
d7b49b10 | 1908 | err = -ENOMEM; |
ad204488 | 1909 | ofs->creator_cred = cred = prepare_creds(); |
c6fe6254 MS |
1910 | if (!cred) |
1911 | goto out_err; | |
1912 | ||
c21c839b CX |
1913 | /* Is there a reason anyone would want not to share whiteouts? */ |
1914 | ofs->share_whiteout = true; | |
1915 | ||
ad204488 | 1916 | ofs->config.index = ovl_index_def; |
5830fb6b | 1917 | ofs->config.uuid = true; |
f168f109 | 1918 | ofs->config.nfs_export = ovl_nfs_export_def; |
795939a9 | 1919 | ofs->config.xino = ovl_xino_def(); |
d5791044 | 1920 | ofs->config.metacopy = ovl_metacopy_def; |
ad204488 | 1921 | err = ovl_parse_opt((char *) data, &ofs->config); |
f45827e8 | 1922 | if (err) |
a9075cdb | 1923 | goto out_err; |
f45827e8 | 1924 | |
e9be9d5e | 1925 | err = -EINVAL; |
ad204488 | 1926 | if (!ofs->config.lowerdir) { |
07f2af7b | 1927 | if (!silent) |
1bd0a3ae | 1928 | pr_err("missing 'lowerdir'\n"); |
a9075cdb | 1929 | goto out_err; |
e9be9d5e MS |
1930 | } |
1931 | ||
b8e42a65 MS |
1932 | err = -ENOMEM; |
1933 | splitlower = kstrdup(ofs->config.lowerdir, GFP_KERNEL); | |
1934 | if (!splitlower) | |
1935 | goto out_err; | |
1936 | ||
d7b49b10 | 1937 | err = -EINVAL; |
b8e42a65 MS |
1938 | numlower = ovl_split_lowerdirs(splitlower); |
1939 | if (numlower > OVL_MAX_STACK) { | |
1940 | pr_err("too many lower directories, limit is %d\n", | |
1941 | OVL_MAX_STACK); | |
1942 | goto out_err; | |
1943 | } | |
1944 | ||
d7b49b10 | 1945 | err = -ENOMEM; |
b8e42a65 MS |
1946 | layers = kcalloc(numlower + 1, sizeof(struct ovl_layer), GFP_KERNEL); |
1947 | if (!layers) | |
1948 | goto out_err; | |
1949 | ||
1950 | ofs->layers = layers; | |
1951 | /* Layer 0 is reserved for upper even if there's no upper */ | |
1952 | ofs->numlayer = 1; | |
1953 | ||
53a08cb9 | 1954 | sb->s_stack_depth = 0; |
cf9a6784 | 1955 | sb->s_maxbytes = MAX_LFS_FILESIZE; |
4d314f78 | 1956 | atomic_long_set(&ofs->last_ino, 1); |
4f119628 | 1957 | /* Assume underlying fs uses 32bit inodes unless proven otherwise */ |
53afcd31 | 1958 | if (ofs->config.xino != OVL_XINO_OFF) { |
0f831ec8 | 1959 | ofs->xino_mode = BITS_PER_LONG - 32; |
53afcd31 AG |
1960 | if (!ofs->xino_mode) { |
1961 | pr_warn("xino not supported on 32bit kernel, falling back to xino=off.\n"); | |
1962 | ofs->config.xino = OVL_XINO_OFF; | |
1963 | } | |
1964 | } | |
795939a9 | 1965 | |
146d62e5 AG |
1966 | /* alloc/destroy_inode needed for setting up traps in inode cache */ |
1967 | sb->s_op = &ovl_super_operations; | |
1968 | ||
ad204488 | 1969 | if (ofs->config.upperdir) { |
335d3fc5 SD |
1970 | struct super_block *upper_sb; |
1971 | ||
d7b49b10 | 1972 | err = -EINVAL; |
ad204488 | 1973 | if (!ofs->config.workdir) { |
1bd0a3ae | 1974 | pr_err("missing 'workdir'\n"); |
a9075cdb | 1975 | goto out_err; |
53a08cb9 | 1976 | } |
e9be9d5e | 1977 | |
b8e42a65 | 1978 | err = ovl_get_upper(sb, ofs, &layers[0], &upperpath); |
53a08cb9 | 1979 | if (err) |
a9075cdb | 1980 | goto out_err; |
2cac0c00 | 1981 | |
335d3fc5 SD |
1982 | upper_sb = ovl_upper_mnt(ofs)->mnt_sb; |
1983 | if (!ovl_should_sync(ofs)) { | |
1984 | ofs->errseq = errseq_sample(&upper_sb->s_wb_err); | |
1985 | if (errseq_check(&upper_sb->s_wb_err, ofs->errseq)) { | |
1986 | err = -EIO; | |
1987 | pr_err("Cannot mount volatile when upperdir has an unseen error. Sync upperdir fs to clear state.\n"); | |
1988 | goto out_err; | |
1989 | } | |
1990 | } | |
1991 | ||
146d62e5 | 1992 | err = ovl_get_workdir(sb, ofs, &upperpath); |
8ed61dc3 | 1993 | if (err) |
a9075cdb | 1994 | goto out_err; |
c6fe6254 | 1995 | |
ad204488 | 1996 | if (!ofs->workdir) |
1751e8a6 | 1997 | sb->s_flags |= SB_RDONLY; |
6e88256e | 1998 | |
335d3fc5 SD |
1999 | sb->s_stack_depth = upper_sb->s_stack_depth; |
2000 | sb->s_time_gran = upper_sb->s_time_gran; | |
e9be9d5e | 2001 | } |
b8e42a65 | 2002 | oe = ovl_get_lowerstack(sb, splitlower, numlower, ofs, layers); |
4155c10a MS |
2003 | err = PTR_ERR(oe); |
2004 | if (IS_ERR(oe)) | |
a9075cdb | 2005 | goto out_err; |
e9be9d5e | 2006 | |
71cbad7e | 2007 | /* If the upper fs is nonexistent, we mark overlayfs r/o too */ |
08f4c7c8 | 2008 | if (!ovl_upper_mnt(ofs)) |
1751e8a6 | 2009 | sb->s_flags |= SB_RDONLY; |
e9be9d5e | 2010 | |
5830fb6b PT |
2011 | if (!ofs->config.uuid && ofs->numfs > 1) { |
2012 | pr_warn("The uuid=off requires a single fs for lower and upper, falling back to uuid=on.\n"); | |
2013 | ofs->config.uuid = true; | |
2014 | } | |
2015 | ||
470c1563 | 2016 | if (!ovl_force_readonly(ofs) && ofs->config.index) { |
146d62e5 | 2017 | err = ovl_get_indexdir(sb, ofs, oe, &upperpath); |
54fb347e | 2018 | if (err) |
4155c10a | 2019 | goto out_free_oe; |
6e88256e | 2020 | |
972d0093 | 2021 | /* Force r/o mount with no index dir */ |
20396365 | 2022 | if (!ofs->indexdir) |
1751e8a6 | 2023 | sb->s_flags |= SB_RDONLY; |
02bcd157 AG |
2024 | } |
2025 | ||
146d62e5 AG |
2026 | err = ovl_check_overlapping_layers(sb, ofs); |
2027 | if (err) | |
2028 | goto out_free_oe; | |
2029 | ||
972d0093 | 2030 | /* Show index=off in /proc/mounts for forced r/o mount */ |
f168f109 | 2031 | if (!ofs->indexdir) { |
ad204488 | 2032 | ofs->config.index = false; |
08f4c7c8 | 2033 | if (ovl_upper_mnt(ofs) && ofs->config.nfs_export) { |
1bd0a3ae | 2034 | pr_warn("NFS export requires an index dir, falling back to nfs_export=off.\n"); |
f168f109 AG |
2035 | ofs->config.nfs_export = false; |
2036 | } | |
2037 | } | |
02bcd157 | 2038 | |
d5791044 | 2039 | if (ofs->config.metacopy && ofs->config.nfs_export) { |
1bd0a3ae | 2040 | pr_warn("NFS export is not supported with metadata only copy up, falling back to nfs_export=off.\n"); |
d5791044 VG |
2041 | ofs->config.nfs_export = false; |
2042 | } | |
2043 | ||
8383f174 AG |
2044 | if (ofs->config.nfs_export) |
2045 | sb->s_export_op = &ovl_export_operations; | |
2046 | ||
51f8f3c4 KK |
2047 | /* Never override disk quota limits or use reserved space */ |
2048 | cap_lower(cred->cap_effective, CAP_SYS_RESOURCE); | |
2049 | ||
655042cc | 2050 | sb->s_magic = OVERLAYFS_SUPER_MAGIC; |
2d2f2d73 MS |
2051 | sb->s_xattr = ofs->config.userxattr ? ovl_user_xattr_handlers : |
2052 | ovl_trusted_xattr_handlers; | |
ad204488 | 2053 | sb->s_fs_info = ofs; |
7c4d37c2 | 2054 | sb->s_flags |= SB_POSIXACL; |
32b1924b | 2055 | sb->s_iflags |= SB_I_SKIP_SYNC; |
655042cc | 2056 | |
c6fe6254 | 2057 | err = -ENOMEM; |
2effc5c2 | 2058 | root_dentry = ovl_get_root(sb, upperpath.dentry, oe); |
e9be9d5e | 2059 | if (!root_dentry) |
4155c10a | 2060 | goto out_free_oe; |
e9be9d5e MS |
2061 | |
2062 | mntput(upperpath.mnt); | |
b8e42a65 | 2063 | kfree(splitlower); |
ed06e069 | 2064 | |
e9be9d5e | 2065 | sb->s_root = root_dentry; |
e9be9d5e MS |
2066 | |
2067 | return 0; | |
2068 | ||
4155c10a MS |
2069 | out_free_oe: |
2070 | ovl_entry_stack_free(oe); | |
b9343632 | 2071 | kfree(oe); |
4155c10a | 2072 | out_err: |
b8e42a65 | 2073 | kfree(splitlower); |
e9be9d5e | 2074 | path_put(&upperpath); |
ad204488 | 2075 | ovl_free_fs(ofs); |
e9be9d5e MS |
2076 | out: |
2077 | return err; | |
2078 | } | |
2079 | ||
2080 | static struct dentry *ovl_mount(struct file_system_type *fs_type, int flags, | |
2081 | const char *dev_name, void *raw_data) | |
2082 | { | |
2083 | return mount_nodev(fs_type, flags, raw_data, ovl_fill_super); | |
2084 | } | |
2085 | ||
2086 | static struct file_system_type ovl_fs_type = { | |
2087 | .owner = THIS_MODULE, | |
ef94b186 | 2088 | .name = "overlay", |
459c7c56 | 2089 | .fs_flags = FS_USERNS_MOUNT, |
e9be9d5e MS |
2090 | .mount = ovl_mount, |
2091 | .kill_sb = kill_anon_super, | |
2092 | }; | |
ef94b186 | 2093 | MODULE_ALIAS_FS("overlay"); |
e9be9d5e | 2094 | |
13cf199d AG |
2095 | static void ovl_inode_init_once(void *foo) |
2096 | { | |
2097 | struct ovl_inode *oi = foo; | |
2098 | ||
2099 | inode_init_once(&oi->vfs_inode); | |
2100 | } | |
2101 | ||
e9be9d5e MS |
2102 | static int __init ovl_init(void) |
2103 | { | |
13cf199d AG |
2104 | int err; |
2105 | ||
2106 | ovl_inode_cachep = kmem_cache_create("ovl_inode", | |
2107 | sizeof(struct ovl_inode), 0, | |
2108 | (SLAB_RECLAIM_ACCOUNT| | |
2109 | SLAB_MEM_SPREAD|SLAB_ACCOUNT), | |
2110 | ovl_inode_init_once); | |
2111 | if (ovl_inode_cachep == NULL) | |
2112 | return -ENOMEM; | |
2113 | ||
2406a307 JX |
2114 | err = ovl_aio_request_cache_init(); |
2115 | if (!err) { | |
2116 | err = register_filesystem(&ovl_fs_type); | |
2117 | if (!err) | |
2118 | return 0; | |
2119 | ||
2120 | ovl_aio_request_cache_destroy(); | |
2121 | } | |
2122 | kmem_cache_destroy(ovl_inode_cachep); | |
13cf199d AG |
2123 | |
2124 | return err; | |
e9be9d5e MS |
2125 | } |
2126 | ||
2127 | static void __exit ovl_exit(void) | |
2128 | { | |
2129 | unregister_filesystem(&ovl_fs_type); | |
13cf199d AG |
2130 | |
2131 | /* | |
2132 | * Make sure all delayed rcu free inodes are flushed before we | |
2133 | * destroy cache. | |
2134 | */ | |
2135 | rcu_barrier(); | |
2136 | kmem_cache_destroy(ovl_inode_cachep); | |
2406a307 | 2137 | ovl_aio_request_cache_destroy(); |
e9be9d5e MS |
2138 | } |
2139 | ||
2140 | module_init(ovl_init); | |
2141 | module_exit(ovl_exit); |