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Commit | Line | Data |
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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> |
1784fbc2 | 19 | #include <linux/fs_context.h> |
dcb399de | 20 | #include <linux/fs_parser.h> |
e9be9d5e | 21 | #include "overlayfs.h" |
7fb7998b | 22 | #include "params.h" |
e9be9d5e MS |
23 | |
24 | MODULE_AUTHOR("Miklos Szeredi <miklos@szeredi.hu>"); | |
25 | MODULE_DESCRIPTION("Overlay filesystem"); | |
26 | MODULE_LICENSE("GPL"); | |
27 | ||
e9be9d5e MS |
28 | |
29 | struct ovl_dir_cache; | |
30 | ||
2d902671 | 31 | static struct dentry *ovl_d_real(struct dentry *dentry, |
fb16043b | 32 | const struct inode *inode) |
d101a125 | 33 | { |
cef4cbff | 34 | struct dentry *real = NULL, *lower; |
184996e9 | 35 | int err; |
d101a125 | 36 | |
e8c985ba MS |
37 | /* It's an overlay file */ |
38 | if (inode && d_inode(dentry) == inode) | |
39 | return dentry; | |
40 | ||
ca4c8a3a | 41 | if (!d_is_reg(dentry)) { |
d101a125 MS |
42 | if (!inode || inode == d_inode(dentry)) |
43 | return dentry; | |
44 | goto bug; | |
45 | } | |
46 | ||
47 | real = ovl_dentry_upper(dentry); | |
2c3d7358 | 48 | if (real && (inode == d_inode(real))) |
d101a125 MS |
49 | return real; |
50 | ||
2c3d7358 VG |
51 | if (real && !inode && ovl_has_upperdata(d_inode(dentry))) |
52 | return real; | |
53 | ||
41665644 | 54 | /* |
42dd69ae | 55 | * Best effort lazy lookup of lowerdata for !inode case to return |
41665644 AG |
56 | * the real lowerdata dentry. The only current caller of d_real() with |
57 | * NULL inode is d_real_inode() from trace_uprobe and this caller is | |
58 | * likely going to be followed reading from the file, before placing | |
59 | * uprobes on offset within the file, so lowerdata should be available | |
60 | * when setting the uprobe. | |
61 | */ | |
184996e9 AL |
62 | err = ovl_verify_lowerdata(dentry); |
63 | if (err) | |
64 | goto bug; | |
cef4cbff MS |
65 | lower = ovl_dentry_lowerdata(dentry); |
66 | if (!lower) | |
d101a125 | 67 | goto bug; |
cef4cbff | 68 | real = lower; |
d101a125 | 69 | |
c4fcfc16 | 70 | /* Handle recursion */ |
fb16043b | 71 | real = d_real(real, inode); |
c4fcfc16 | 72 | |
d101a125 MS |
73 | if (!inode || inode == d_inode(real)) |
74 | return real; | |
d101a125 | 75 | bug: |
cef4cbff MS |
76 | WARN(1, "%s(%pd4, %s:%lu): real dentry (%p/%lu) not found\n", |
77 | __func__, dentry, inode ? inode->i_sb->s_id : "NULL", | |
78 | inode ? inode->i_ino : 0, real, | |
79 | real && d_inode(real) ? d_inode(real)->i_ino : 0); | |
d101a125 MS |
80 | return dentry; |
81 | } | |
82 | ||
3bb7df92 | 83 | static int ovl_revalidate_real(struct dentry *d, unsigned int flags, bool weak) |
7c03b5d4 | 84 | { |
7c03b5d4 MS |
85 | int ret = 1; |
86 | ||
41665644 AG |
87 | if (!d) |
88 | return 1; | |
89 | ||
3bb7df92 MS |
90 | if (weak) { |
91 | if (d->d_flags & DCACHE_OP_WEAK_REVALIDATE) | |
92 | ret = d->d_op->d_weak_revalidate(d, flags); | |
93 | } else if (d->d_flags & DCACHE_OP_REVALIDATE) { | |
94 | ret = d->d_op->d_revalidate(d, flags); | |
95 | if (!ret) { | |
96 | if (!(flags & LOOKUP_RCU)) | |
97 | d_invalidate(d); | |
98 | ret = -ESTALE; | |
7c03b5d4 MS |
99 | } |
100 | } | |
3bb7df92 | 101 | return ret; |
7c03b5d4 MS |
102 | } |
103 | ||
3bb7df92 MS |
104 | static int ovl_dentry_revalidate_common(struct dentry *dentry, |
105 | unsigned int flags, bool weak) | |
7c03b5d4 | 106 | { |
c54719c9 AV |
107 | struct ovl_entry *oe; |
108 | struct ovl_path *lowerstack; | |
672e4268 | 109 | struct inode *inode = d_inode_rcu(dentry); |
bccece1e | 110 | struct dentry *upper; |
7c03b5d4 MS |
111 | unsigned int i; |
112 | int ret = 1; | |
113 | ||
672e4268 CZ |
114 | /* Careful in RCU mode */ |
115 | if (!inode) | |
116 | return -ECHILD; | |
117 | ||
c54719c9 AV |
118 | oe = OVL_I_E(inode); |
119 | lowerstack = ovl_lowerstack(oe); | |
672e4268 | 120 | upper = ovl_i_dentry_upper(inode); |
bccece1e MS |
121 | if (upper) |
122 | ret = ovl_revalidate_real(upper, flags, weak); | |
123 | ||
5522c9c7 AG |
124 | for (i = 0; ret > 0 && i < ovl_numlower(oe); i++) |
125 | ret = ovl_revalidate_real(lowerstack[i].dentry, flags, weak); | |
126 | ||
7c03b5d4 MS |
127 | return ret; |
128 | } | |
129 | ||
3bb7df92 MS |
130 | static int ovl_dentry_revalidate(struct dentry *dentry, unsigned int flags) |
131 | { | |
132 | return ovl_dentry_revalidate_common(dentry, flags, false); | |
133 | } | |
134 | ||
135 | static int ovl_dentry_weak_revalidate(struct dentry *dentry, unsigned int flags) | |
136 | { | |
137 | return ovl_dentry_revalidate_common(dentry, flags, true); | |
138 | } | |
139 | ||
e9be9d5e | 140 | static const struct dentry_operations ovl_dentry_operations = { |
d101a125 | 141 | .d_real = ovl_d_real, |
7c03b5d4 MS |
142 | .d_revalidate = ovl_dentry_revalidate, |
143 | .d_weak_revalidate = ovl_dentry_weak_revalidate, | |
144 | }; | |
145 | ||
13cf199d AG |
146 | static struct kmem_cache *ovl_inode_cachep; |
147 | ||
148 | static struct inode *ovl_alloc_inode(struct super_block *sb) | |
149 | { | |
fd60b288 | 150 | struct ovl_inode *oi = alloc_inode_sb(sb, ovl_inode_cachep, GFP_KERNEL); |
13cf199d | 151 | |
b3885bd6 HN |
152 | if (!oi) |
153 | return NULL; | |
154 | ||
04a01ac7 | 155 | oi->cache = NULL; |
cf31c463 | 156 | oi->redirect = NULL; |
04a01ac7 | 157 | oi->version = 0; |
13c72075 | 158 | oi->flags = 0; |
09d8b586 | 159 | oi->__upperdentry = NULL; |
2b21da92 | 160 | oi->lowerdata_redirect = NULL; |
0af950f5 | 161 | oi->oe = NULL; |
a015dafc | 162 | mutex_init(&oi->lock); |
25b7713a | 163 | |
13cf199d AG |
164 | return &oi->vfs_inode; |
165 | } | |
166 | ||
0b269ded | 167 | static void ovl_free_inode(struct inode *inode) |
13cf199d | 168 | { |
0b269ded | 169 | struct ovl_inode *oi = OVL_I(inode); |
13cf199d | 170 | |
0b269ded | 171 | kfree(oi->redirect); |
d9e8319a | 172 | kfree(oi->oe); |
0b269ded AV |
173 | mutex_destroy(&oi->lock); |
174 | kmem_cache_free(ovl_inode_cachep, oi); | |
13cf199d AG |
175 | } |
176 | ||
177 | static void ovl_destroy_inode(struct inode *inode) | |
178 | { | |
09d8b586 MS |
179 | struct ovl_inode *oi = OVL_I(inode); |
180 | ||
181 | dput(oi->__upperdentry); | |
d9e8319a | 182 | ovl_stack_put(ovl_lowerstack(oi->oe), ovl_numlower(oi->oe)); |
2664bd08 VG |
183 | if (S_ISDIR(inode->i_mode)) |
184 | ovl_dir_cache_free(inode); | |
2b21da92 AG |
185 | else |
186 | kfree(oi->lowerdata_redirect); | |
13cf199d AG |
187 | } |
188 | ||
a9075cdb MS |
189 | static void ovl_put_super(struct super_block *sb) |
190 | { | |
f01d0889 | 191 | struct ovl_fs *ofs = OVL_FS(sb); |
a9075cdb | 192 | |
1784fbc2 CB |
193 | if (ofs) |
194 | ovl_free_fs(ofs); | |
a9075cdb MS |
195 | } |
196 | ||
e8d4bfe3 | 197 | /* Sync real dirty inodes in upper filesystem (if it exists) */ |
e593b2bf AG |
198 | static int ovl_sync_fs(struct super_block *sb, int wait) |
199 | { | |
f01d0889 | 200 | struct ovl_fs *ofs = OVL_FS(sb); |
e593b2bf AG |
201 | struct super_block *upper_sb; |
202 | int ret; | |
203 | ||
335d3fc5 SD |
204 | ret = ovl_sync_status(ofs); |
205 | /* | |
206 | * We have to always set the err, because the return value isn't | |
207 | * checked in syncfs, and instead indirectly return an error via | |
208 | * the sb's writeback errseq, which VFS inspects after this call. | |
209 | */ | |
210 | if (ret < 0) { | |
211 | errseq_set(&sb->s_wb_err, -EIO); | |
212 | return -EIO; | |
213 | } | |
214 | ||
215 | if (!ret) | |
216 | return ret; | |
e8d4bfe3 CX |
217 | |
218 | /* | |
32b1924b KK |
219 | * Not called for sync(2) call or an emergency sync (SB_I_SKIP_SYNC). |
220 | * All the super blocks will be iterated, including upper_sb. | |
e8d4bfe3 CX |
221 | * |
222 | * If this is a syncfs(2) call, then we do need to call | |
223 | * sync_filesystem() on upper_sb, but enough if we do it when being | |
224 | * called with wait == 1. | |
225 | */ | |
226 | if (!wait) | |
e593b2bf AG |
227 | return 0; |
228 | ||
08f4c7c8 | 229 | upper_sb = ovl_upper_mnt(ofs)->mnt_sb; |
e8d4bfe3 | 230 | |
e593b2bf | 231 | down_read(&upper_sb->s_umount); |
e8d4bfe3 | 232 | ret = sync_filesystem(upper_sb); |
e593b2bf | 233 | up_read(&upper_sb->s_umount); |
e8d4bfe3 | 234 | |
e593b2bf AG |
235 | return ret; |
236 | } | |
237 | ||
cc259639 AW |
238 | /** |
239 | * ovl_statfs | |
9c5dd803 | 240 | * @dentry: The dentry to query |
cc259639 AW |
241 | * @buf: The struct kstatfs to fill in with stats |
242 | * | |
243 | * Get the filesystem statistics. As writes always target the upper layer | |
4ebc5818 | 244 | * filesystem pass the statfs to the upper filesystem (if it exists) |
cc259639 AW |
245 | */ |
246 | static int ovl_statfs(struct dentry *dentry, struct kstatfs *buf) | |
247 | { | |
b0504bfe AG |
248 | struct super_block *sb = dentry->d_sb; |
249 | struct ovl_fs *ofs = OVL_FS(sb); | |
250 | struct dentry *root_dentry = sb->s_root; | |
cc259639 AW |
251 | struct path path; |
252 | int err; | |
253 | ||
4ebc5818 | 254 | ovl_path_real(root_dentry, &path); |
cc259639 AW |
255 | |
256 | err = vfs_statfs(&path, buf); | |
257 | if (!err) { | |
6b2d5fe4 | 258 | buf->f_namelen = ofs->namelen; |
cc259639 | 259 | buf->f_type = OVERLAYFS_SUPER_MAGIC; |
b0504bfe AG |
260 | if (ovl_has_fsid(ofs)) |
261 | buf->f_fsid = uuid_to_fsid(sb->s_uuid.b); | |
cc259639 AW |
262 | } |
263 | ||
264 | return err; | |
265 | } | |
266 | ||
e9be9d5e | 267 | static const struct super_operations ovl_super_operations = { |
13cf199d | 268 | .alloc_inode = ovl_alloc_inode, |
0b269ded | 269 | .free_inode = ovl_free_inode, |
13cf199d AG |
270 | .destroy_inode = ovl_destroy_inode, |
271 | .drop_inode = generic_delete_inode, | |
e9be9d5e | 272 | .put_super = ovl_put_super, |
e593b2bf | 273 | .sync_fs = ovl_sync_fs, |
cc259639 | 274 | .statfs = ovl_statfs, |
f45827e8 | 275 | .show_options = ovl_show_options, |
e9be9d5e MS |
276 | }; |
277 | ||
e9be9d5e | 278 | #define OVL_WORKDIR_NAME "work" |
02bcd157 | 279 | #define OVL_INDEXDIR_NAME "index" |
e9be9d5e | 280 | |
ad204488 | 281 | static struct dentry *ovl_workdir_create(struct ovl_fs *ofs, |
6b8aa129 | 282 | const char *name, bool persist) |
e9be9d5e | 283 | { |
ad204488 | 284 | struct inode *dir = ofs->workbasedir->d_inode; |
08f4c7c8 | 285 | struct vfsmount *mnt = ovl_upper_mnt(ofs); |
e9be9d5e MS |
286 | struct dentry *work; |
287 | int err; | |
288 | bool retried = false; | |
289 | ||
5955102c | 290 | inode_lock_nested(dir, I_MUTEX_PARENT); |
e9be9d5e | 291 | retry: |
22f289ce | 292 | work = ovl_lookup_upper(ofs, name, ofs->workbasedir, strlen(name)); |
e9be9d5e MS |
293 | |
294 | if (!IS_ERR(work)) { | |
c11b9fdd MS |
295 | struct iattr attr = { |
296 | .ia_valid = ATTR_MODE, | |
32a3d848 | 297 | .ia_mode = S_IFDIR | 0, |
c11b9fdd | 298 | }; |
e9be9d5e MS |
299 | |
300 | if (work->d_inode) { | |
301 | err = -EEXIST; | |
302 | if (retried) | |
303 | goto out_dput; | |
304 | ||
6b8aa129 AG |
305 | if (persist) |
306 | goto out_unlock; | |
307 | ||
e9be9d5e | 308 | retried = true; |
576bb263 | 309 | err = ovl_workdir_cleanup(ofs, dir, mnt, work, 0); |
e9be9d5e | 310 | dput(work); |
235ce9ed AG |
311 | if (err == -EINVAL) { |
312 | work = ERR_PTR(err); | |
313 | goto out_unlock; | |
314 | } | |
e9be9d5e MS |
315 | goto retry; |
316 | } | |
317 | ||
576bb263 | 318 | err = ovl_mkdir_real(ofs, dir, &work, attr.ia_mode); |
1f5573cf MS |
319 | if (err) |
320 | goto out_dput; | |
321 | ||
322 | /* Weird filesystem returning with hashed negative (kernfs)? */ | |
323 | err = -EINVAL; | |
324 | if (d_really_is_negative(work)) | |
325 | goto out_dput; | |
c11b9fdd | 326 | |
cb348edb MS |
327 | /* |
328 | * Try to remove POSIX ACL xattrs from workdir. We are good if: | |
329 | * | |
330 | * a) success (there was a POSIX ACL xattr and was removed) | |
331 | * b) -ENODATA (there was no POSIX ACL xattr) | |
332 | * c) -EOPNOTSUPP (POSIX ACL xattrs are not supported) | |
333 | * | |
334 | * There are various other error values that could effectively | |
335 | * mean that the xattr doesn't exist (e.g. -ERANGE is returned | |
336 | * if the xattr name is too long), but the set of filesystems | |
337 | * allowed as upper are limited to "normal" ones, where checking | |
338 | * for the above two errors is sufficient. | |
339 | */ | |
31acceb9 | 340 | err = ovl_do_remove_acl(ofs, work, XATTR_NAME_POSIX_ACL_DEFAULT); |
e1ff3dd1 | 341 | if (err && err != -ENODATA && err != -EOPNOTSUPP) |
c11b9fdd MS |
342 | goto out_dput; |
343 | ||
31acceb9 | 344 | err = ovl_do_remove_acl(ofs, work, XATTR_NAME_POSIX_ACL_ACCESS); |
e1ff3dd1 | 345 | if (err && err != -ENODATA && err != -EOPNOTSUPP) |
c11b9fdd MS |
346 | goto out_dput; |
347 | ||
348 | /* Clear any inherited mode bits */ | |
349 | inode_lock(work->d_inode); | |
a15506ea | 350 | err = ovl_do_notify_change(ofs, work, &attr); |
c11b9fdd MS |
351 | inode_unlock(work->d_inode); |
352 | if (err) | |
353 | goto out_dput; | |
6b8aa129 AG |
354 | } else { |
355 | err = PTR_ERR(work); | |
356 | goto out_err; | |
e9be9d5e MS |
357 | } |
358 | out_unlock: | |
2068cf7d | 359 | inode_unlock(dir); |
e9be9d5e MS |
360 | return work; |
361 | ||
362 | out_dput: | |
363 | dput(work); | |
6b8aa129 | 364 | out_err: |
1bd0a3ae | 365 | pr_warn("failed to create directory %s/%s (errno: %i); mounting read-only\n", |
ad204488 | 366 | ofs->config.workdir, name, -err); |
6b8aa129 | 367 | work = NULL; |
e9be9d5e MS |
368 | goto out_unlock; |
369 | } | |
370 | ||
2d343087 | 371 | static int ovl_check_namelen(const struct path *path, struct ovl_fs *ofs, |
6b2d5fe4 | 372 | const char *name) |
ab508822 | 373 | { |
ab508822 | 374 | struct kstatfs statfs; |
6b2d5fe4 MS |
375 | int err = vfs_statfs(path, &statfs); |
376 | ||
377 | if (err) | |
1bd0a3ae | 378 | pr_err("statfs failed on '%s'\n", name); |
6b2d5fe4 MS |
379 | else |
380 | ofs->namelen = max(ofs->namelen, statfs.f_namelen); | |
381 | ||
382 | return err; | |
383 | } | |
384 | ||
385 | static int ovl_lower_dir(const char *name, struct path *path, | |
f4288844 | 386 | struct ovl_fs *ofs, int *stack_depth) |
6b2d5fe4 | 387 | { |
e487d889 | 388 | int fh_type; |
6b2d5fe4 | 389 | int err; |
ab508822 | 390 | |
6b2d5fe4 MS |
391 | err = ovl_check_namelen(path, ofs, name); |
392 | if (err) | |
b8e42a65 | 393 | return err; |
6b2d5fe4 | 394 | |
ab508822 MS |
395 | *stack_depth = max(*stack_depth, path->mnt->mnt_sb->s_stack_depth); |
396 | ||
02bcd157 | 397 | /* |
f168f109 AG |
398 | * The inodes index feature and NFS export need to encode and decode |
399 | * file handles, so they require that all layers support them. | |
02bcd157 | 400 | */ |
e487d889 | 401 | fh_type = ovl_can_decode_fh(path->dentry->d_sb); |
f168f109 | 402 | if ((ofs->config.nfs_export || |
e487d889 | 403 | (ofs->config.index && ofs->config.upperdir)) && !fh_type) { |
02bcd157 | 404 | ofs->config.index = false; |
f168f109 | 405 | ofs->config.nfs_export = false; |
1bd0a3ae | 406 | pr_warn("fs on '%s' does not support file handles, falling back to index=off,nfs_export=off.\n", |
f168f109 | 407 | name); |
02bcd157 | 408 | } |
16aac5ad | 409 | ofs->nofh |= !fh_type; |
b0e0f697 AG |
410 | /* |
411 | * Decoding origin file handle is required for persistent st_ino. | |
412 | * Without persistent st_ino, xino=auto falls back to xino=off. | |
413 | */ | |
414 | if (ofs->config.xino == OVL_XINO_AUTO && | |
415 | ofs->config.upperdir && !fh_type) { | |
416 | ofs->config.xino = OVL_XINO_OFF; | |
417 | pr_warn("fs on '%s' does not support file handles, falling back to xino=off.\n", | |
418 | name); | |
419 | } | |
02bcd157 | 420 | |
e487d889 AG |
421 | /* Check if lower fs has 32bit inode numbers */ |
422 | if (fh_type != FILEID_INO32_GEN) | |
0f831ec8 | 423 | ofs->xino_mode = -1; |
e487d889 | 424 | |
ab508822 | 425 | return 0; |
ab508822 MS |
426 | } |
427 | ||
e9be9d5e MS |
428 | /* Workdir should not be subdir of upperdir and vice versa */ |
429 | static bool ovl_workdir_ok(struct dentry *workdir, struct dentry *upperdir) | |
430 | { | |
431 | bool ok = false; | |
432 | ||
433 | if (workdir != upperdir) { | |
434 | ok = (lock_rename(workdir, upperdir) == NULL); | |
435 | unlock_rename(workdir, upperdir); | |
436 | } | |
437 | return ok; | |
438 | } | |
439 | ||
0eb45fc3 AG |
440 | static int ovl_own_xattr_get(const struct xattr_handler *handler, |
441 | struct dentry *dentry, struct inode *inode, | |
442 | const char *name, void *buffer, size_t size) | |
443 | { | |
48fab5d7 | 444 | return -EOPNOTSUPP; |
0eb45fc3 AG |
445 | } |
446 | ||
d837a49b | 447 | static int ovl_own_xattr_set(const struct xattr_handler *handler, |
39f60c1c | 448 | struct mnt_idmap *idmap, |
d837a49b MS |
449 | struct dentry *dentry, struct inode *inode, |
450 | const char *name, const void *value, | |
451 | size_t size, int flags) | |
452 | { | |
48fab5d7 | 453 | return -EOPNOTSUPP; |
d837a49b MS |
454 | } |
455 | ||
0eb45fc3 AG |
456 | static int ovl_other_xattr_get(const struct xattr_handler *handler, |
457 | struct dentry *dentry, struct inode *inode, | |
458 | const char *name, void *buffer, size_t size) | |
459 | { | |
1d88f183 | 460 | return ovl_xattr_get(dentry, inode, name, buffer, size); |
0eb45fc3 AG |
461 | } |
462 | ||
0e585ccc | 463 | static int ovl_other_xattr_set(const struct xattr_handler *handler, |
39f60c1c | 464 | struct mnt_idmap *idmap, |
0e585ccc AG |
465 | struct dentry *dentry, struct inode *inode, |
466 | const char *name, const void *value, | |
467 | size_t size, int flags) | |
468 | { | |
1d88f183 | 469 | return ovl_xattr_set(dentry, inode, name, value, size, flags); |
0e585ccc AG |
470 | } |
471 | ||
2d2f2d73 MS |
472 | static const struct xattr_handler ovl_own_trusted_xattr_handler = { |
473 | .prefix = OVL_XATTR_TRUSTED_PREFIX, | |
474 | .get = ovl_own_xattr_get, | |
475 | .set = ovl_own_xattr_set, | |
476 | }; | |
477 | ||
478 | static const struct xattr_handler ovl_own_user_xattr_handler = { | |
479 | .prefix = OVL_XATTR_USER_PREFIX, | |
0eb45fc3 | 480 | .get = ovl_own_xattr_get, |
d837a49b MS |
481 | .set = ovl_own_xattr_set, |
482 | }; | |
483 | ||
484 | static const struct xattr_handler ovl_other_xattr_handler = { | |
485 | .prefix = "", /* catch all */ | |
0eb45fc3 | 486 | .get = ovl_other_xattr_get, |
d837a49b MS |
487 | .set = ovl_other_xattr_set, |
488 | }; | |
489 | ||
2d2f2d73 | 490 | static const struct xattr_handler *ovl_trusted_xattr_handlers[] = { |
2d2f2d73 MS |
491 | &ovl_own_trusted_xattr_handler, |
492 | &ovl_other_xattr_handler, | |
493 | NULL | |
494 | }; | |
495 | ||
496 | static const struct xattr_handler *ovl_user_xattr_handlers[] = { | |
2d2f2d73 | 497 | &ovl_own_user_xattr_handler, |
d837a49b MS |
498 | &ovl_other_xattr_handler, |
499 | NULL | |
500 | }; | |
501 | ||
146d62e5 AG |
502 | static int ovl_setup_trap(struct super_block *sb, struct dentry *dir, |
503 | struct inode **ptrap, const char *name) | |
504 | { | |
505 | struct inode *trap; | |
506 | int err; | |
507 | ||
508 | trap = ovl_get_trap_inode(sb, dir); | |
1dac6f5b AB |
509 | err = PTR_ERR_OR_ZERO(trap); |
510 | if (err) { | |
146d62e5 | 511 | if (err == -ELOOP) |
1bd0a3ae | 512 | pr_err("conflicting %s path\n", name); |
146d62e5 AG |
513 | return err; |
514 | } | |
515 | ||
516 | *ptrap = trap; | |
517 | return 0; | |
518 | } | |
519 | ||
0be0bfd2 AG |
520 | /* |
521 | * Determine how we treat concurrent use of upperdir/workdir based on the | |
522 | * index feature. This is papering over mount leaks of container runtimes, | |
523 | * for example, an old overlay mount is leaked and now its upperdir is | |
524 | * attempted to be used as a lower layer in a new overlay mount. | |
525 | */ | |
526 | static int ovl_report_in_use(struct ovl_fs *ofs, const char *name) | |
527 | { | |
528 | if (ofs->config.index) { | |
1bd0a3ae | 529 | 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 |
530 | name); |
531 | return -EBUSY; | |
532 | } else { | |
1bd0a3ae | 533 | 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 |
534 | name); |
535 | return 0; | |
536 | } | |
537 | } | |
538 | ||
146d62e5 | 539 | static int ovl_get_upper(struct super_block *sb, struct ovl_fs *ofs, |
b36a5780 CB |
540 | struct ovl_layer *upper_layer, |
541 | const struct path *upperpath) | |
6ee8acf0 | 542 | { |
5064975e | 543 | struct vfsmount *upper_mnt; |
6ee8acf0 MS |
544 | int err; |
545 | ||
e21a6c57 AG |
546 | /* Upperdir path should not be r/o */ |
547 | if (__mnt_is_readonly(upperpath->mnt)) { | |
1bd0a3ae | 548 | pr_err("upper fs is r/o, try multi-lower layers mount\n"); |
6ee8acf0 MS |
549 | err = -EINVAL; |
550 | goto out; | |
551 | } | |
552 | ||
ad204488 | 553 | err = ovl_check_namelen(upperpath, ofs, ofs->config.upperdir); |
6ee8acf0 MS |
554 | if (err) |
555 | goto out; | |
556 | ||
b8e42a65 | 557 | err = ovl_setup_trap(sb, upperpath->dentry, &upper_layer->trap, |
146d62e5 AG |
558 | "upperdir"); |
559 | if (err) | |
560 | goto out; | |
561 | ||
5064975e MS |
562 | upper_mnt = clone_private_mount(upperpath); |
563 | err = PTR_ERR(upper_mnt); | |
564 | if (IS_ERR(upper_mnt)) { | |
1bd0a3ae | 565 | pr_err("failed to clone upperpath\n"); |
5064975e MS |
566 | goto out; |
567 | } | |
568 | ||
569 | /* Don't inherit atime flags */ | |
570 | upper_mnt->mnt_flags &= ~(MNT_NOATIME | MNT_NODIRATIME | MNT_RELATIME); | |
b8e42a65 MS |
571 | upper_layer->mnt = upper_mnt; |
572 | upper_layer->idx = 0; | |
573 | upper_layer->fsid = 0; | |
8c25741a | 574 | |
b36a5780 CB |
575 | err = -ENOMEM; |
576 | upper_layer->name = kstrdup(ofs->config.upperdir, GFP_KERNEL); | |
577 | if (!upper_layer->name) | |
578 | goto out; | |
579 | ||
654255fa JX |
580 | /* |
581 | * Inherit SB_NOSEC flag from upperdir. | |
582 | * | |
583 | * This optimization changes behavior when a security related attribute | |
584 | * (suid/sgid/security.*) is changed on an underlying layer. This is | |
585 | * okay because we don't yet have guarantees in that case, but it will | |
586 | * need careful treatment once we want to honour changes to underlying | |
587 | * filesystems. | |
588 | */ | |
589 | if (upper_mnt->mnt_sb->s_flags & SB_NOSEC) | |
590 | sb->s_flags |= SB_NOSEC; | |
591 | ||
08f4c7c8 | 592 | if (ovl_inuse_trylock(ovl_upper_mnt(ofs)->mnt_root)) { |
8c25741a | 593 | ofs->upperdir_locked = true; |
8c25741a | 594 | } else { |
0be0bfd2 AG |
595 | err = ovl_report_in_use(ofs, "upperdir"); |
596 | if (err) | |
597 | goto out; | |
8c25741a MS |
598 | } |
599 | ||
6ee8acf0 MS |
600 | err = 0; |
601 | out: | |
602 | return err; | |
603 | } | |
604 | ||
cad218ab AG |
605 | /* |
606 | * Returns 1 if RENAME_WHITEOUT is supported, 0 if not supported and | |
607 | * negative values if error is encountered. | |
608 | */ | |
576bb263 | 609 | static int ovl_check_rename_whiteout(struct ovl_fs *ofs) |
cad218ab | 610 | { |
576bb263 | 611 | struct dentry *workdir = ofs->workdir; |
cad218ab AG |
612 | struct inode *dir = d_inode(workdir); |
613 | struct dentry *temp; | |
614 | struct dentry *dest; | |
615 | struct dentry *whiteout; | |
616 | struct name_snapshot name; | |
617 | int err; | |
618 | ||
619 | inode_lock_nested(dir, I_MUTEX_PARENT); | |
620 | ||
576bb263 | 621 | temp = ovl_create_temp(ofs, workdir, OVL_CATTR(S_IFREG | 0)); |
cad218ab AG |
622 | err = PTR_ERR(temp); |
623 | if (IS_ERR(temp)) | |
624 | goto out_unlock; | |
625 | ||
576bb263 | 626 | dest = ovl_lookup_temp(ofs, workdir); |
cad218ab AG |
627 | err = PTR_ERR(dest); |
628 | if (IS_ERR(dest)) { | |
629 | dput(temp); | |
630 | goto out_unlock; | |
631 | } | |
632 | ||
633 | /* Name is inline and stable - using snapshot as a copy helper */ | |
634 | take_dentry_name_snapshot(&name, temp); | |
576bb263 | 635 | err = ovl_do_rename(ofs, dir, temp, dir, dest, RENAME_WHITEOUT); |
cad218ab AG |
636 | if (err) { |
637 | if (err == -EINVAL) | |
638 | err = 0; | |
639 | goto cleanup_temp; | |
640 | } | |
641 | ||
22f289ce | 642 | whiteout = ovl_lookup_upper(ofs, name.name.name, workdir, name.name.len); |
cad218ab AG |
643 | err = PTR_ERR(whiteout); |
644 | if (IS_ERR(whiteout)) | |
645 | goto cleanup_temp; | |
646 | ||
647 | err = ovl_is_whiteout(whiteout); | |
648 | ||
649 | /* Best effort cleanup of whiteout and temp file */ | |
650 | if (err) | |
576bb263 | 651 | ovl_cleanup(ofs, dir, whiteout); |
cad218ab AG |
652 | dput(whiteout); |
653 | ||
654 | cleanup_temp: | |
576bb263 | 655 | ovl_cleanup(ofs, dir, temp); |
cad218ab AG |
656 | release_dentry_name_snapshot(&name); |
657 | dput(temp); | |
658 | dput(dest); | |
659 | ||
660 | out_unlock: | |
661 | inode_unlock(dir); | |
662 | ||
663 | return err; | |
664 | } | |
665 | ||
576bb263 CB |
666 | static struct dentry *ovl_lookup_or_create(struct ovl_fs *ofs, |
667 | struct dentry *parent, | |
c86243b0 VG |
668 | const char *name, umode_t mode) |
669 | { | |
670 | size_t len = strlen(name); | |
671 | struct dentry *child; | |
672 | ||
673 | inode_lock_nested(parent->d_inode, I_MUTEX_PARENT); | |
22f289ce | 674 | child = ovl_lookup_upper(ofs, name, parent, len); |
c86243b0 | 675 | if (!IS_ERR(child) && !child->d_inode) |
576bb263 | 676 | child = ovl_create_real(ofs, parent->d_inode, child, |
c86243b0 VG |
677 | OVL_CATTR(mode)); |
678 | inode_unlock(parent->d_inode); | |
679 | dput(parent); | |
680 | ||
681 | return child; | |
682 | } | |
683 | ||
684 | /* | |
685 | * Creates $workdir/work/incompat/volatile/dirty file if it is not already | |
686 | * present. | |
687 | */ | |
688 | static int ovl_create_volatile_dirty(struct ovl_fs *ofs) | |
689 | { | |
690 | unsigned int ctr; | |
691 | struct dentry *d = dget(ofs->workbasedir); | |
692 | static const char *const volatile_path[] = { | |
693 | OVL_WORKDIR_NAME, "incompat", "volatile", "dirty" | |
694 | }; | |
695 | const char *const *name = volatile_path; | |
696 | ||
697 | for (ctr = ARRAY_SIZE(volatile_path); ctr; ctr--, name++) { | |
576bb263 | 698 | d = ovl_lookup_or_create(ofs, d, *name, ctr > 1 ? S_IFDIR : S_IFREG); |
c86243b0 VG |
699 | if (IS_ERR(d)) |
700 | return PTR_ERR(d); | |
701 | } | |
702 | dput(d); | |
703 | return 0; | |
704 | } | |
705 | ||
146d62e5 | 706 | static int ovl_make_workdir(struct super_block *sb, struct ovl_fs *ofs, |
2d343087 | 707 | const struct path *workpath) |
8ed61dc3 | 708 | { |
08f4c7c8 | 709 | struct vfsmount *mnt = ovl_upper_mnt(ofs); |
2b1a7746 MS |
710 | struct dentry *workdir; |
711 | struct file *tmpfile; | |
d80172c2 AG |
712 | bool rename_whiteout; |
713 | bool d_type; | |
e487d889 | 714 | int fh_type; |
8ed61dc3 MS |
715 | int err; |
716 | ||
2ba9d57e AG |
717 | err = mnt_want_write(mnt); |
718 | if (err) | |
719 | return err; | |
720 | ||
235ce9ed AG |
721 | workdir = ovl_workdir_create(ofs, OVL_WORKDIR_NAME, false); |
722 | err = PTR_ERR(workdir); | |
723 | if (IS_ERR_OR_NULL(workdir)) | |
2ba9d57e | 724 | goto out; |
8ed61dc3 | 725 | |
235ce9ed AG |
726 | ofs->workdir = workdir; |
727 | ||
146d62e5 AG |
728 | err = ovl_setup_trap(sb, ofs->workdir, &ofs->workdir_trap, "workdir"); |
729 | if (err) | |
730 | goto out; | |
731 | ||
8ed61dc3 MS |
732 | /* |
733 | * Upper should support d_type, else whiteouts are visible. Given | |
734 | * workdir and upper are on same fs, we can do iterate_dir() on | |
735 | * workdir. This check requires successful creation of workdir in | |
736 | * previous step. | |
737 | */ | |
738 | err = ovl_check_d_type_supported(workpath); | |
739 | if (err < 0) | |
2ba9d57e | 740 | goto out; |
8ed61dc3 | 741 | |
d80172c2 AG |
742 | d_type = err; |
743 | if (!d_type) | |
1bd0a3ae | 744 | pr_warn("upper fs needs to support d_type.\n"); |
8ed61dc3 MS |
745 | |
746 | /* Check if upper/work fs supports O_TMPFILE */ | |
2b1a7746 MS |
747 | tmpfile = ovl_do_tmpfile(ofs, ofs->workdir, S_IFREG | 0); |
748 | ofs->tmpfile = !IS_ERR(tmpfile); | |
ad204488 | 749 | if (ofs->tmpfile) |
2b1a7746 | 750 | fput(tmpfile); |
8ed61dc3 | 751 | else |
1bd0a3ae | 752 | pr_warn("upper fs does not support tmpfile.\n"); |
8ed61dc3 | 753 | |
cad218ab AG |
754 | |
755 | /* Check if upper/work fs supports RENAME_WHITEOUT */ | |
576bb263 | 756 | err = ovl_check_rename_whiteout(ofs); |
cad218ab AG |
757 | if (err < 0) |
758 | goto out; | |
759 | ||
d80172c2 AG |
760 | rename_whiteout = err; |
761 | if (!rename_whiteout) | |
cad218ab AG |
762 | pr_warn("upper fs does not support RENAME_WHITEOUT.\n"); |
763 | ||
8ed61dc3 | 764 | /* |
2d2f2d73 | 765 | * Check if upper/work fs supports (trusted|user).overlay.* xattr |
8ed61dc3 | 766 | */ |
c914c0e2 | 767 | err = ovl_setxattr(ofs, ofs->workdir, OVL_XATTR_OPAQUE, "0", 1); |
8ed61dc3 | 768 | if (err) { |
b10b85fe | 769 | pr_warn("failed to set xattr on upper\n"); |
ad204488 | 770 | ofs->noxattr = true; |
af5f2396 AG |
771 | if (ovl_redirect_follow(ofs)) { |
772 | ofs->config.redirect_mode = OVL_REDIRECT_NOFOLLOW; | |
773 | pr_warn("...falling back to redirect_dir=nofollow.\n"); | |
774 | } | |
775 | if (ofs->config.metacopy) { | |
b0e0f697 | 776 | ofs->config.metacopy = false; |
af5f2396 AG |
777 | pr_warn("...falling back to metacopy=off.\n"); |
778 | } | |
779 | if (ofs->config.index) { | |
780 | ofs->config.index = false; | |
781 | pr_warn("...falling back to index=off.\n"); | |
b0e0f697 | 782 | } |
d9544c1b AG |
783 | if (ovl_has_fsid(ofs)) { |
784 | ofs->config.uuid = OVL_UUID_NULL; | |
785 | pr_warn("...falling back to uuid=null.\n"); | |
786 | } | |
b0e0f697 AG |
787 | /* |
788 | * xattr support is required for persistent st_ino. | |
789 | * Without persistent st_ino, xino=auto falls back to xino=off. | |
790 | */ | |
791 | if (ofs->config.xino == OVL_XINO_AUTO) { | |
792 | ofs->config.xino = OVL_XINO_OFF; | |
b10b85fe | 793 | pr_warn("...falling back to xino=off.\n"); |
b0e0f697 | 794 | } |
b10b85fe MS |
795 | if (err == -EPERM && !ofs->config.userxattr) |
796 | pr_info("try mounting with 'userxattr' option\n"); | |
2ba9d57e | 797 | err = 0; |
8ed61dc3 | 798 | } else { |
c914c0e2 | 799 | ovl_removexattr(ofs, ofs->workdir, OVL_XATTR_OPAQUE); |
8ed61dc3 MS |
800 | } |
801 | ||
d80172c2 AG |
802 | /* |
803 | * We allowed sub-optimal upper fs configuration and don't want to break | |
804 | * users over kernel upgrade, but we never allowed remote upper fs, so | |
805 | * we can enforce strict requirements for remote upper fs. | |
806 | */ | |
807 | if (ovl_dentry_remote(ofs->workdir) && | |
808 | (!d_type || !rename_whiteout || ofs->noxattr)) { | |
809 | pr_err("upper fs missing required features.\n"); | |
810 | err = -EINVAL; | |
811 | goto out; | |
812 | } | |
813 | ||
c86243b0 VG |
814 | /* |
815 | * For volatile mount, create a incompat/volatile/dirty file to keep | |
816 | * track of it. | |
817 | */ | |
818 | if (ofs->config.ovl_volatile) { | |
819 | err = ovl_create_volatile_dirty(ofs); | |
820 | if (err < 0) { | |
821 | pr_err("Failed to create volatile/dirty file.\n"); | |
822 | goto out; | |
823 | } | |
824 | } | |
825 | ||
8ed61dc3 | 826 | /* Check if upper/work fs supports file handles */ |
e487d889 AG |
827 | fh_type = ovl_can_decode_fh(ofs->workdir->d_sb); |
828 | if (ofs->config.index && !fh_type) { | |
ad204488 | 829 | ofs->config.index = false; |
1bd0a3ae | 830 | pr_warn("upper fs does not support file handles, falling back to index=off.\n"); |
8ed61dc3 | 831 | } |
16aac5ad | 832 | ofs->nofh |= !fh_type; |
8ed61dc3 | 833 | |
e487d889 AG |
834 | /* Check if upper fs has 32bit inode numbers */ |
835 | if (fh_type != FILEID_INO32_GEN) | |
0f831ec8 | 836 | ofs->xino_mode = -1; |
e487d889 | 837 | |
f168f109 AG |
838 | /* NFS export of r/w mount depends on index */ |
839 | if (ofs->config.nfs_export && !ofs->config.index) { | |
1bd0a3ae | 840 | pr_warn("NFS export requires \"index=on\", falling back to nfs_export=off.\n"); |
f168f109 AG |
841 | ofs->config.nfs_export = false; |
842 | } | |
2ba9d57e AG |
843 | out: |
844 | mnt_drop_write(mnt); | |
845 | return err; | |
8ed61dc3 MS |
846 | } |
847 | ||
146d62e5 | 848 | static int ovl_get_workdir(struct super_block *sb, struct ovl_fs *ofs, |
b36a5780 CB |
849 | const struct path *upperpath, |
850 | const struct path *workpath) | |
520d7c86 MS |
851 | { |
852 | int err; | |
520d7c86 MS |
853 | |
854 | err = -EINVAL; | |
b36a5780 | 855 | if (upperpath->mnt != workpath->mnt) { |
1bd0a3ae | 856 | pr_err("workdir and upperdir must reside under the same mount\n"); |
b36a5780 | 857 | return err; |
520d7c86 | 858 | } |
b36a5780 | 859 | if (!ovl_workdir_ok(workpath->dentry, upperpath->dentry)) { |
1bd0a3ae | 860 | pr_err("workdir and upperdir must be separate subtrees\n"); |
b36a5780 | 861 | return err; |
520d7c86 MS |
862 | } |
863 | ||
b36a5780 | 864 | ofs->workbasedir = dget(workpath->dentry); |
8c25741a | 865 | |
8c25741a | 866 | if (ovl_inuse_trylock(ofs->workbasedir)) { |
ad204488 | 867 | ofs->workdir_locked = true; |
520d7c86 | 868 | } else { |
0be0bfd2 AG |
869 | err = ovl_report_in_use(ofs, "workdir"); |
870 | if (err) | |
b36a5780 | 871 | return err; |
520d7c86 MS |
872 | } |
873 | ||
0be0bfd2 AG |
874 | err = ovl_setup_trap(sb, ofs->workbasedir, &ofs->workbasedir_trap, |
875 | "workdir"); | |
876 | if (err) | |
b36a5780 | 877 | return err; |
bca44b52 | 878 | |
b36a5780 | 879 | return ovl_make_workdir(sb, ofs, workpath); |
520d7c86 MS |
880 | } |
881 | ||
146d62e5 | 882 | static int ovl_get_indexdir(struct super_block *sb, struct ovl_fs *ofs, |
2d343087 | 883 | struct ovl_entry *oe, const struct path *upperpath) |
f7e3a7d9 | 884 | { |
08f4c7c8 | 885 | struct vfsmount *mnt = ovl_upper_mnt(ofs); |
235ce9ed | 886 | struct dentry *indexdir; |
f7e3a7d9 MS |
887 | int err; |
888 | ||
2ba9d57e AG |
889 | err = mnt_want_write(mnt); |
890 | if (err) | |
891 | return err; | |
892 | ||
f7e3a7d9 | 893 | /* Verify lower root is upper root origin */ |
610afc0b | 894 | err = ovl_verify_origin(ofs, upperpath->dentry, |
5522c9c7 | 895 | ovl_lowerstack(oe)->dentry, true); |
f7e3a7d9 | 896 | if (err) { |
1bd0a3ae | 897 | pr_err("failed to verify upper root origin\n"); |
f7e3a7d9 MS |
898 | goto out; |
899 | } | |
900 | ||
470c1563 AG |
901 | /* index dir will act also as workdir */ |
902 | iput(ofs->workdir_trap); | |
903 | ofs->workdir_trap = NULL; | |
904 | dput(ofs->workdir); | |
905 | ofs->workdir = NULL; | |
235ce9ed AG |
906 | indexdir = ovl_workdir_create(ofs, OVL_INDEXDIR_NAME, true); |
907 | if (IS_ERR(indexdir)) { | |
908 | err = PTR_ERR(indexdir); | |
909 | } else if (indexdir) { | |
910 | ofs->indexdir = indexdir; | |
911 | ofs->workdir = dget(indexdir); | |
20396365 | 912 | |
146d62e5 AG |
913 | err = ovl_setup_trap(sb, ofs->indexdir, &ofs->indexdir_trap, |
914 | "indexdir"); | |
915 | if (err) | |
916 | goto out; | |
917 | ||
ad1d615c AG |
918 | /* |
919 | * Verify upper root is exclusively associated with index dir. | |
2d2f2d73 | 920 | * Older kernels stored upper fh in ".overlay.origin" |
ad1d615c AG |
921 | * xattr. If that xattr exists, verify that it is a match to |
922 | * upper dir file handle. In any case, verify or set xattr | |
2d2f2d73 | 923 | * ".overlay.upper" to indicate that index may have |
ad1d615c AG |
924 | * directory entries. |
925 | */ | |
610afc0b MS |
926 | if (ovl_check_origin_xattr(ofs, ofs->indexdir)) { |
927 | err = ovl_verify_set_fh(ofs, ofs->indexdir, | |
928 | OVL_XATTR_ORIGIN, | |
ad1d615c AG |
929 | upperpath->dentry, true, false); |
930 | if (err) | |
1bd0a3ae | 931 | pr_err("failed to verify index dir 'origin' xattr\n"); |
ad1d615c | 932 | } |
610afc0b MS |
933 | err = ovl_verify_upper(ofs, ofs->indexdir, upperpath->dentry, |
934 | true); | |
f7e3a7d9 | 935 | if (err) |
1bd0a3ae | 936 | pr_err("failed to verify index dir 'upper' xattr\n"); |
f7e3a7d9 MS |
937 | |
938 | /* Cleanup bad/stale/orphan index entries */ | |
939 | if (!err) | |
1eff1a1d | 940 | err = ovl_indexdir_cleanup(ofs); |
f7e3a7d9 | 941 | } |
ad204488 | 942 | if (err || !ofs->indexdir) |
1bd0a3ae | 943 | pr_warn("try deleting index dir or mounting with '-o index=off' to disable inodes index.\n"); |
f7e3a7d9 MS |
944 | |
945 | out: | |
2ba9d57e | 946 | mnt_drop_write(mnt); |
f7e3a7d9 MS |
947 | return err; |
948 | } | |
949 | ||
9df085f3 AG |
950 | static bool ovl_lower_uuid_ok(struct ovl_fs *ofs, const uuid_t *uuid) |
951 | { | |
952 | unsigned int i; | |
953 | ||
08f4c7c8 | 954 | if (!ofs->config.nfs_export && !ovl_upper_mnt(ofs)) |
9df085f3 AG |
955 | return true; |
956 | ||
a888db31 AG |
957 | /* |
958 | * We allow using single lower with null uuid for index and nfs_export | |
959 | * for example to support those features with single lower squashfs. | |
960 | * To avoid regressions in setups of overlay with re-formatted lower | |
961 | * squashfs, do not allow decoding origin with lower null uuid unless | |
962 | * user opted-in to one of the new features that require following the | |
963 | * lower inode of non-dir upper. | |
964 | */ | |
ca45275c | 965 | if (ovl_allow_offline_changes(ofs) && uuid_is_null(uuid)) |
a888db31 AG |
966 | return false; |
967 | ||
1b81dddd | 968 | for (i = 0; i < ofs->numfs; i++) { |
9df085f3 AG |
969 | /* |
970 | * We use uuid to associate an overlay lower file handle with a | |
971 | * lower layer, so we can accept lower fs with null uuid as long | |
972 | * as all lower layers with null uuid are on the same fs. | |
7e63c87f AG |
973 | * if we detect multiple lower fs with the same uuid, we |
974 | * disable lower file handle decoding on all of them. | |
9df085f3 | 975 | */ |
1b81dddd AG |
976 | if (ofs->fs[i].is_lower && |
977 | uuid_equal(&ofs->fs[i].sb->s_uuid, uuid)) { | |
07f1e596 | 978 | ofs->fs[i].bad_uuid = true; |
9df085f3 | 979 | return false; |
7e63c87f | 980 | } |
9df085f3 AG |
981 | } |
982 | return true; | |
983 | } | |
984 | ||
5148626b | 985 | /* Get a unique fsid for the layer */ |
9df085f3 | 986 | static int ovl_get_fsid(struct ovl_fs *ofs, const struct path *path) |
5148626b | 987 | { |
9df085f3 | 988 | struct super_block *sb = path->mnt->mnt_sb; |
5148626b AG |
989 | unsigned int i; |
990 | dev_t dev; | |
991 | int err; | |
7e63c87f | 992 | bool bad_uuid = false; |
b0e0f697 | 993 | bool warn = false; |
5148626b | 994 | |
07f1e596 AG |
995 | for (i = 0; i < ofs->numfs; i++) { |
996 | if (ofs->fs[i].sb == sb) | |
997 | return i; | |
5148626b AG |
998 | } |
999 | ||
9df085f3 | 1000 | if (!ovl_lower_uuid_ok(ofs, &sb->s_uuid)) { |
7e63c87f | 1001 | bad_uuid = true; |
b0e0f697 AG |
1002 | if (ofs->config.xino == OVL_XINO_AUTO) { |
1003 | ofs->config.xino = OVL_XINO_OFF; | |
1004 | warn = true; | |
1005 | } | |
7e63c87f AG |
1006 | if (ofs->config.index || ofs->config.nfs_export) { |
1007 | ofs->config.index = false; | |
1008 | ofs->config.nfs_export = false; | |
b0e0f697 AG |
1009 | warn = true; |
1010 | } | |
1011 | if (warn) { | |
1012 | pr_warn("%s uuid detected in lower fs '%pd2', falling back to xino=%s,index=off,nfs_export=off.\n", | |
7e63c87f AG |
1013 | uuid_is_null(&sb->s_uuid) ? "null" : |
1014 | "conflicting", | |
dcb399de | 1015 | path->dentry, ovl_xino_mode(&ofs->config)); |
7e63c87f | 1016 | } |
9df085f3 AG |
1017 | } |
1018 | ||
5148626b AG |
1019 | err = get_anon_bdev(&dev); |
1020 | if (err) { | |
1bd0a3ae | 1021 | pr_err("failed to get anonymous bdev for lowerpath\n"); |
5148626b AG |
1022 | return err; |
1023 | } | |
1024 | ||
07f1e596 AG |
1025 | ofs->fs[ofs->numfs].sb = sb; |
1026 | ofs->fs[ofs->numfs].pseudo_dev = dev; | |
1027 | ofs->fs[ofs->numfs].bad_uuid = bad_uuid; | |
5148626b | 1028 | |
07f1e596 | 1029 | return ofs->numfs++; |
5148626b AG |
1030 | } |
1031 | ||
37ebf056 AG |
1032 | /* |
1033 | * The fsid after the last lower fsid is used for the data layers. | |
1034 | * It is a "null fs" with a null sb, null uuid, and no pseudo dev. | |
1035 | */ | |
1036 | static int ovl_get_data_fsid(struct ovl_fs *ofs) | |
1037 | { | |
1038 | return ofs->numfs; | |
1039 | } | |
1040 | ||
1041 | ||
94375f9d | 1042 | static int ovl_get_layers(struct super_block *sb, struct ovl_fs *ofs, |
b36a5780 | 1043 | struct ovl_fs_context *ctx, struct ovl_layer *layers) |
520d7c86 MS |
1044 | { |
1045 | int err; | |
1046 | unsigned int i; | |
b36a5780 | 1047 | size_t nr_merged_lower; |
520d7c86 | 1048 | |
b36a5780 | 1049 | ofs->fs = kcalloc(ctx->nr + 2, sizeof(struct ovl_sb), GFP_KERNEL); |
07f1e596 | 1050 | if (ofs->fs == NULL) |
9e88f905 | 1051 | return -ENOMEM; |
5148626b | 1052 | |
37ebf056 AG |
1053 | /* |
1054 | * idx/fsid 0 are reserved for upper fs even with lower only overlay | |
1055 | * and the last fsid is reserved for "null fs" of the data layers. | |
1056 | */ | |
07f1e596 AG |
1057 | ofs->numfs++; |
1058 | ||
07f1e596 | 1059 | /* |
b7bf9908 AG |
1060 | * All lower layers that share the same fs as upper layer, use the same |
1061 | * pseudo_dev as upper layer. Allocate fs[0].pseudo_dev even for lower | |
1062 | * only overlay to simplify ovl_fs_free(). | |
1b81dddd | 1063 | * is_lower will be set if upper fs is shared with a lower layer. |
07f1e596 | 1064 | */ |
b7bf9908 AG |
1065 | err = get_anon_bdev(&ofs->fs[0].pseudo_dev); |
1066 | if (err) { | |
1067 | pr_err("failed to get anonymous bdev for upper fs\n"); | |
9e88f905 | 1068 | return err; |
b7bf9908 AG |
1069 | } |
1070 | ||
08f4c7c8 MS |
1071 | if (ovl_upper_mnt(ofs)) { |
1072 | ofs->fs[0].sb = ovl_upper_mnt(ofs)->mnt_sb; | |
1b81dddd | 1073 | ofs->fs[0].is_lower = false; |
07f1e596 AG |
1074 | } |
1075 | ||
b36a5780 CB |
1076 | nr_merged_lower = ctx->nr - ctx->nr_data; |
1077 | for (i = 0; i < ctx->nr; i++) { | |
1078 | struct ovl_fs_context_layer *l = &ctx->lower[i]; | |
520d7c86 | 1079 | struct vfsmount *mnt; |
146d62e5 | 1080 | struct inode *trap; |
5148626b | 1081 | int fsid; |
520d7c86 | 1082 | |
b36a5780 CB |
1083 | if (i < nr_merged_lower) |
1084 | fsid = ovl_get_fsid(ofs, &l->path); | |
37ebf056 AG |
1085 | else |
1086 | fsid = ovl_get_data_fsid(ofs); | |
9e88f905 AG |
1087 | if (fsid < 0) |
1088 | return fsid; | |
520d7c86 | 1089 | |
24f14009 | 1090 | /* |
1091 | * Check if lower root conflicts with this overlay layers before | |
1092 | * checking if it is in-use as upperdir/workdir of "another" | |
1093 | * mount, because we do not bother to check in ovl_is_inuse() if | |
1094 | * the upperdir/workdir is in fact in-use by our | |
1095 | * upperdir/workdir. | |
1096 | */ | |
b36a5780 | 1097 | err = ovl_setup_trap(sb, l->path.dentry, &trap, "lowerdir"); |
146d62e5 | 1098 | if (err) |
9e88f905 | 1099 | return err; |
146d62e5 | 1100 | |
b36a5780 | 1101 | if (ovl_is_inuse(l->path.dentry)) { |
0be0bfd2 | 1102 | err = ovl_report_in_use(ofs, "lowerdir"); |
24f14009 | 1103 | if (err) { |
1104 | iput(trap); | |
9e88f905 | 1105 | return err; |
24f14009 | 1106 | } |
0be0bfd2 AG |
1107 | } |
1108 | ||
b36a5780 | 1109 | mnt = clone_private_mount(&l->path); |
520d7c86 MS |
1110 | err = PTR_ERR(mnt); |
1111 | if (IS_ERR(mnt)) { | |
1bd0a3ae | 1112 | pr_err("failed to clone lowerpath\n"); |
146d62e5 | 1113 | iput(trap); |
9e88f905 | 1114 | return err; |
520d7c86 | 1115 | } |
5148626b | 1116 | |
520d7c86 MS |
1117 | /* |
1118 | * Make lower layers R/O. That way fchmod/fchown on lower file | |
1119 | * will fail instead of modifying lower fs. | |
1120 | */ | |
1121 | mnt->mnt_flags |= MNT_READONLY | MNT_NOATIME; | |
1122 | ||
13464165 MS |
1123 | layers[ofs->numlayer].trap = trap; |
1124 | layers[ofs->numlayer].mnt = mnt; | |
1125 | layers[ofs->numlayer].idx = ofs->numlayer; | |
1126 | layers[ofs->numlayer].fsid = fsid; | |
1127 | layers[ofs->numlayer].fs = &ofs->fs[fsid]; | |
b36a5780 CB |
1128 | layers[ofs->numlayer].name = l->name; |
1129 | l->name = NULL; | |
94375f9d | 1130 | ofs->numlayer++; |
1b81dddd | 1131 | ofs->fs[fsid].is_lower = true; |
520d7c86 | 1132 | } |
e487d889 | 1133 | |
795939a9 AG |
1134 | /* |
1135 | * When all layers on same fs, overlay can use real inode numbers. | |
926e94d7 AG |
1136 | * With mount option "xino=<on|auto>", mounter declares that there are |
1137 | * enough free high bits in underlying fs to hold the unique fsid. | |
795939a9 AG |
1138 | * If overlayfs does encounter underlying inodes using the high xino |
1139 | * bits reserved for fsid, it emits a warning and uses the original | |
dfe51d47 AG |
1140 | * inode number or a non persistent inode number allocated from a |
1141 | * dedicated range. | |
795939a9 | 1142 | */ |
08f4c7c8 | 1143 | if (ofs->numfs - !ovl_upper_mnt(ofs) == 1) { |
0f831ec8 AG |
1144 | if (ofs->config.xino == OVL_XINO_ON) |
1145 | pr_info("\"xino=on\" is useless with all layers on same fs, ignore.\n"); | |
1146 | ofs->xino_mode = 0; | |
53afcd31 AG |
1147 | } else if (ofs->config.xino == OVL_XINO_OFF) { |
1148 | ofs->xino_mode = -1; | |
926e94d7 | 1149 | } else if (ofs->xino_mode < 0) { |
795939a9 | 1150 | /* |
07f1e596 | 1151 | * This is a roundup of number of bits needed for encoding |
dfe51d47 AG |
1152 | * fsid, where fsid 0 is reserved for upper fs (even with |
1153 | * lower only overlay) +1 extra bit is reserved for the non | |
1154 | * persistent inode number range that is used for resolving | |
1155 | * xino lower bits overflow. | |
795939a9 | 1156 | */ |
dfe51d47 AG |
1157 | BUILD_BUG_ON(ilog2(OVL_MAX_STACK) > 30); |
1158 | ofs->xino_mode = ilog2(ofs->numfs - 1) + 2; | |
795939a9 AG |
1159 | } |
1160 | ||
0f831ec8 | 1161 | if (ofs->xino_mode > 0) { |
1bd0a3ae | 1162 | pr_info("\"xino\" feature enabled using %d upper inode bits.\n", |
0f831ec8 | 1163 | ofs->xino_mode); |
795939a9 | 1164 | } |
e487d889 | 1165 | |
9e88f905 | 1166 | return 0; |
520d7c86 MS |
1167 | } |
1168 | ||
4155c10a | 1169 | static struct ovl_entry *ovl_get_lowerstack(struct super_block *sb, |
b36a5780 CB |
1170 | struct ovl_fs_context *ctx, |
1171 | struct ovl_fs *ofs, | |
1172 | struct ovl_layer *layers) | |
53dbb0b4 MS |
1173 | { |
1174 | int err; | |
b8e42a65 | 1175 | unsigned int i; |
b36a5780 | 1176 | size_t nr_merged_lower; |
4155c10a | 1177 | struct ovl_entry *oe; |
b36a5780 CB |
1178 | struct ovl_path *lowerstack; |
1179 | ||
1180 | struct ovl_fs_context_layer *l; | |
53dbb0b4 | 1181 | |
b36a5780 | 1182 | if (!ofs->config.upperdir && ctx->nr == 1) { |
1bd0a3ae | 1183 | pr_err("at least 2 lowerdir are needed while upperdir nonexistent\n"); |
b8e42a65 | 1184 | return ERR_PTR(-EINVAL); |
53dbb0b4 MS |
1185 | } |
1186 | ||
b36a5780 CB |
1187 | err = -EINVAL; |
1188 | for (i = 0; i < ctx->nr; i++) { | |
1189 | l = &ctx->lower[i]; | |
53dbb0b4 | 1190 | |
b36a5780 | 1191 | err = ovl_lower_dir(l->name, &l->path, ofs, &sb->s_stack_depth); |
53dbb0b4 | 1192 | if (err) |
b36a5780 | 1193 | return ERR_PTR(err); |
53dbb0b4 MS |
1194 | } |
1195 | ||
1196 | err = -EINVAL; | |
1197 | sb->s_stack_depth++; | |
1198 | if (sb->s_stack_depth > FILESYSTEM_MAX_STACK_DEPTH) { | |
1bd0a3ae | 1199 | pr_err("maximum fs stacking depth exceeded\n"); |
b36a5780 | 1200 | return ERR_PTR(err); |
53dbb0b4 MS |
1201 | } |
1202 | ||
b36a5780 | 1203 | err = ovl_get_layers(sb, ofs, ctx, layers); |
4155c10a | 1204 | if (err) |
b36a5780 | 1205 | return ERR_PTR(err); |
4155c10a MS |
1206 | |
1207 | err = -ENOMEM; | |
37ebf056 | 1208 | /* Data-only layers are not merged in root directory */ |
b36a5780 CB |
1209 | nr_merged_lower = ctx->nr - ctx->nr_data; |
1210 | oe = ovl_alloc_entry(nr_merged_lower); | |
4155c10a | 1211 | if (!oe) |
b36a5780 | 1212 | return ERR_PTR(err); |
4155c10a | 1213 | |
5522c9c7 | 1214 | lowerstack = ovl_lowerstack(oe); |
b36a5780 CB |
1215 | for (i = 0; i < nr_merged_lower; i++) { |
1216 | l = &ctx->lower[i]; | |
1217 | lowerstack[i].dentry = dget(l->path.dentry); | |
1218 | lowerstack[i].layer = &ofs->layers[i + 1]; | |
4155c10a | 1219 | } |
b36a5780 | 1220 | ofs->numdatalayer = ctx->nr_data; |
4155c10a MS |
1221 | |
1222 | return oe; | |
53dbb0b4 MS |
1223 | } |
1224 | ||
146d62e5 AG |
1225 | /* |
1226 | * Check if this layer root is a descendant of: | |
1227 | * - another layer of this overlayfs instance | |
1228 | * - upper/work dir of any overlayfs instance | |
146d62e5 | 1229 | */ |
0be0bfd2 | 1230 | static int ovl_check_layer(struct super_block *sb, struct ovl_fs *ofs, |
708fa015 MS |
1231 | struct dentry *dentry, const char *name, |
1232 | bool is_lower) | |
146d62e5 | 1233 | { |
9179c21d | 1234 | struct dentry *next = dentry, *parent; |
146d62e5 AG |
1235 | int err = 0; |
1236 | ||
9179c21d | 1237 | if (!dentry) |
146d62e5 AG |
1238 | return 0; |
1239 | ||
9179c21d MS |
1240 | parent = dget_parent(next); |
1241 | ||
1242 | /* Walk back ancestors to root (inclusive) looking for traps */ | |
1243 | while (!err && parent != next) { | |
708fa015 | 1244 | if (is_lower && ovl_lookup_trap_inode(sb, parent)) { |
146d62e5 | 1245 | err = -ELOOP; |
1bd0a3ae | 1246 | pr_err("overlapping %s path\n", name); |
0be0bfd2 AG |
1247 | } else if (ovl_is_inuse(parent)) { |
1248 | err = ovl_report_in_use(ofs, name); | |
146d62e5 | 1249 | } |
146d62e5 | 1250 | next = parent; |
9179c21d MS |
1251 | parent = dget_parent(next); |
1252 | dput(next); | |
146d62e5 AG |
1253 | } |
1254 | ||
9179c21d | 1255 | dput(parent); |
146d62e5 AG |
1256 | |
1257 | return err; | |
1258 | } | |
1259 | ||
1260 | /* | |
1261 | * Check if any of the layers or work dirs overlap. | |
1262 | */ | |
1263 | static int ovl_check_overlapping_layers(struct super_block *sb, | |
1264 | struct ovl_fs *ofs) | |
1265 | { | |
1266 | int i, err; | |
1267 | ||
08f4c7c8 MS |
1268 | if (ovl_upper_mnt(ofs)) { |
1269 | err = ovl_check_layer(sb, ofs, ovl_upper_mnt(ofs)->mnt_root, | |
708fa015 | 1270 | "upperdir", false); |
146d62e5 AG |
1271 | if (err) |
1272 | return err; | |
1273 | ||
1274 | /* | |
1275 | * Checking workbasedir avoids hitting ovl_is_inuse(parent) of | |
1276 | * this instance and covers overlapping work and index dirs, | |
1277 | * unless work or index dir have been moved since created inside | |
1278 | * workbasedir. In that case, we already have their traps in | |
1279 | * inode cache and we will catch that case on lookup. | |
1280 | */ | |
708fa015 MS |
1281 | err = ovl_check_layer(sb, ofs, ofs->workbasedir, "workdir", |
1282 | false); | |
146d62e5 AG |
1283 | if (err) |
1284 | return err; | |
1285 | } | |
1286 | ||
94375f9d | 1287 | for (i = 1; i < ofs->numlayer; i++) { |
0be0bfd2 | 1288 | err = ovl_check_layer(sb, ofs, |
94375f9d | 1289 | ofs->layers[i].mnt->mnt_root, |
708fa015 | 1290 | "lowerdir", true); |
146d62e5 AG |
1291 | if (err) |
1292 | return err; | |
1293 | } | |
1294 | ||
1295 | return 0; | |
1296 | } | |
1297 | ||
2effc5c2 AG |
1298 | static struct dentry *ovl_get_root(struct super_block *sb, |
1299 | struct dentry *upperdentry, | |
1300 | struct ovl_entry *oe) | |
1301 | { | |
1302 | struct dentry *root; | |
5522c9c7 | 1303 | struct ovl_path *lowerpath = ovl_lowerstack(oe); |
62c832ed AG |
1304 | unsigned long ino = d_inode(lowerpath->dentry)->i_ino; |
1305 | int fsid = lowerpath->layer->fsid; | |
1306 | struct ovl_inode_params oip = { | |
1307 | .upperdentry = upperdentry, | |
0af950f5 | 1308 | .oe = oe, |
62c832ed | 1309 | }; |
2effc5c2 AG |
1310 | |
1311 | root = d_make_root(ovl_new_inode(sb, S_IFDIR, 0)); | |
1312 | if (!root) | |
1313 | return NULL; | |
1314 | ||
2effc5c2 | 1315 | if (upperdentry) { |
62c832ed AG |
1316 | /* Root inode uses upper st_ino/i_ino */ |
1317 | ino = d_inode(upperdentry)->i_ino; | |
1318 | fsid = 0; | |
2effc5c2 | 1319 | ovl_dentry_set_upper_alias(root); |
610afc0b | 1320 | if (ovl_is_impuredir(sb, upperdentry)) |
2effc5c2 AG |
1321 | ovl_set_flag(OVL_IMPURE, d_inode(root)); |
1322 | } | |
1323 | ||
1324 | /* Root is always merge -> can have whiteouts */ | |
1325 | ovl_set_flag(OVL_WHITEOUTS, d_inode(root)); | |
1326 | ovl_dentry_set_flag(OVL_E_CONNECTED, root); | |
1327 | ovl_set_upperdata(d_inode(root)); | |
62c832ed | 1328 | ovl_inode_init(d_inode(root), &oip, ino, fsid); |
0af950f5 | 1329 | ovl_dentry_init_flags(root, upperdentry, oe, DCACHE_OP_WEAK_REVALIDATE); |
367d002d AG |
1330 | /* root keeps a reference of upperdentry */ |
1331 | dget(upperdentry); | |
2effc5c2 AG |
1332 | |
1333 | return root; | |
1334 | } | |
1335 | ||
7fb7998b | 1336 | int ovl_fill_super(struct super_block *sb, struct fs_context *fc) |
e9be9d5e | 1337 | { |
1784fbc2 CB |
1338 | struct ovl_fs *ofs = sb->s_fs_info; |
1339 | struct ovl_fs_context *ctx = fc->fs_private; | |
e9be9d5e | 1340 | struct dentry *root_dentry; |
4155c10a | 1341 | struct ovl_entry *oe; |
b8e42a65 | 1342 | struct ovl_layer *layers; |
51f8f3c4 | 1343 | struct cred *cred; |
e9be9d5e MS |
1344 | int err; |
1345 | ||
9efb069d | 1346 | err = -EIO; |
1784fbc2 CB |
1347 | if (WARN_ON(fc->user_ns != current_user_ns())) |
1348 | goto out_err; | |
9efb069d | 1349 | |
f4288844 MS |
1350 | sb->s_d_op = &ovl_dentry_operations; |
1351 | ||
d7b49b10 | 1352 | err = -ENOMEM; |
ad204488 | 1353 | ofs->creator_cred = cred = prepare_creds(); |
c6fe6254 MS |
1354 | if (!cred) |
1355 | goto out_err; | |
1356 | ||
1784fbc2 | 1357 | err = ovl_fs_params_verify(ctx, &ofs->config); |
f45827e8 | 1358 | if (err) |
a9075cdb | 1359 | goto out_err; |
f45827e8 | 1360 | |
e9be9d5e | 1361 | err = -EINVAL; |
b36a5780 | 1362 | if (ctx->nr == 0) { |
1784fbc2 | 1363 | if (!(fc->sb_flags & SB_SILENT)) |
1bd0a3ae | 1364 | pr_err("missing 'lowerdir'\n"); |
a9075cdb | 1365 | goto out_err; |
e9be9d5e MS |
1366 | } |
1367 | ||
b8e42a65 | 1368 | err = -ENOMEM; |
b36a5780 | 1369 | layers = kcalloc(ctx->nr + 1, sizeof(struct ovl_layer), GFP_KERNEL); |
b8e42a65 MS |
1370 | if (!layers) |
1371 | goto out_err; | |
1372 | ||
1373 | ofs->layers = layers; | |
1374 | /* Layer 0 is reserved for upper even if there's no upper */ | |
1375 | ofs->numlayer = 1; | |
1376 | ||
53a08cb9 | 1377 | sb->s_stack_depth = 0; |
cf9a6784 | 1378 | sb->s_maxbytes = MAX_LFS_FILESIZE; |
4d314f78 | 1379 | atomic_long_set(&ofs->last_ino, 1); |
4f119628 | 1380 | /* Assume underlying fs uses 32bit inodes unless proven otherwise */ |
53afcd31 | 1381 | if (ofs->config.xino != OVL_XINO_OFF) { |
0f831ec8 | 1382 | ofs->xino_mode = BITS_PER_LONG - 32; |
53afcd31 AG |
1383 | if (!ofs->xino_mode) { |
1384 | pr_warn("xino not supported on 32bit kernel, falling back to xino=off.\n"); | |
1385 | ofs->config.xino = OVL_XINO_OFF; | |
1386 | } | |
1387 | } | |
795939a9 | 1388 | |
146d62e5 AG |
1389 | /* alloc/destroy_inode needed for setting up traps in inode cache */ |
1390 | sb->s_op = &ovl_super_operations; | |
1391 | ||
ad204488 | 1392 | if (ofs->config.upperdir) { |
335d3fc5 SD |
1393 | struct super_block *upper_sb; |
1394 | ||
d7b49b10 | 1395 | err = -EINVAL; |
ad204488 | 1396 | if (!ofs->config.workdir) { |
1bd0a3ae | 1397 | pr_err("missing 'workdir'\n"); |
a9075cdb | 1398 | goto out_err; |
53a08cb9 | 1399 | } |
e9be9d5e | 1400 | |
b36a5780 | 1401 | err = ovl_get_upper(sb, ofs, &layers[0], &ctx->upper); |
53a08cb9 | 1402 | if (err) |
a9075cdb | 1403 | goto out_err; |
2cac0c00 | 1404 | |
335d3fc5 SD |
1405 | upper_sb = ovl_upper_mnt(ofs)->mnt_sb; |
1406 | if (!ovl_should_sync(ofs)) { | |
1407 | ofs->errseq = errseq_sample(&upper_sb->s_wb_err); | |
1408 | if (errseq_check(&upper_sb->s_wb_err, ofs->errseq)) { | |
1409 | err = -EIO; | |
1410 | pr_err("Cannot mount volatile when upperdir has an unseen error. Sync upperdir fs to clear state.\n"); | |
1411 | goto out_err; | |
1412 | } | |
1413 | } | |
1414 | ||
b36a5780 | 1415 | err = ovl_get_workdir(sb, ofs, &ctx->upper, &ctx->work); |
8ed61dc3 | 1416 | if (err) |
a9075cdb | 1417 | goto out_err; |
c6fe6254 | 1418 | |
ad204488 | 1419 | if (!ofs->workdir) |
1751e8a6 | 1420 | sb->s_flags |= SB_RDONLY; |
6e88256e | 1421 | |
335d3fc5 SD |
1422 | sb->s_stack_depth = upper_sb->s_stack_depth; |
1423 | sb->s_time_gran = upper_sb->s_time_gran; | |
e9be9d5e | 1424 | } |
b36a5780 | 1425 | oe = ovl_get_lowerstack(sb, ctx, ofs, layers); |
4155c10a MS |
1426 | err = PTR_ERR(oe); |
1427 | if (IS_ERR(oe)) | |
a9075cdb | 1428 | goto out_err; |
e9be9d5e | 1429 | |
71cbad7e | 1430 | /* If the upper fs is nonexistent, we mark overlayfs r/o too */ |
08f4c7c8 | 1431 | if (!ovl_upper_mnt(ofs)) |
1751e8a6 | 1432 | sb->s_flags |= SB_RDONLY; |
e9be9d5e | 1433 | |
b0504bfe AG |
1434 | if (!ovl_origin_uuid(ofs) && ofs->numfs > 1) { |
1435 | pr_warn("The uuid=off requires a single fs for lower and upper, falling back to uuid=null.\n"); | |
1436 | ofs->config.uuid = OVL_UUID_NULL; | |
d9544c1b AG |
1437 | } else if (ovl_has_fsid(ofs) && ovl_upper_mnt(ofs)) { |
1438 | /* Use per instance persistent uuid/fsid */ | |
1439 | ovl_init_uuid_xattr(sb, ofs, &ctx->upper); | |
5830fb6b PT |
1440 | } |
1441 | ||
470c1563 | 1442 | if (!ovl_force_readonly(ofs) && ofs->config.index) { |
b36a5780 | 1443 | err = ovl_get_indexdir(sb, ofs, oe, &ctx->upper); |
54fb347e | 1444 | if (err) |
4155c10a | 1445 | goto out_free_oe; |
6e88256e | 1446 | |
972d0093 | 1447 | /* Force r/o mount with no index dir */ |
20396365 | 1448 | if (!ofs->indexdir) |
1751e8a6 | 1449 | sb->s_flags |= SB_RDONLY; |
02bcd157 AG |
1450 | } |
1451 | ||
146d62e5 AG |
1452 | err = ovl_check_overlapping_layers(sb, ofs); |
1453 | if (err) | |
1454 | goto out_free_oe; | |
1455 | ||
972d0093 | 1456 | /* Show index=off in /proc/mounts for forced r/o mount */ |
f168f109 | 1457 | if (!ofs->indexdir) { |
ad204488 | 1458 | ofs->config.index = false; |
08f4c7c8 | 1459 | if (ovl_upper_mnt(ofs) && ofs->config.nfs_export) { |
1bd0a3ae | 1460 | pr_warn("NFS export requires an index dir, falling back to nfs_export=off.\n"); |
f168f109 AG |
1461 | ofs->config.nfs_export = false; |
1462 | } | |
1463 | } | |
02bcd157 | 1464 | |
d5791044 | 1465 | if (ofs->config.metacopy && ofs->config.nfs_export) { |
1bd0a3ae | 1466 | pr_warn("NFS export is not supported with metadata only copy up, falling back to nfs_export=off.\n"); |
d5791044 VG |
1467 | ofs->config.nfs_export = false; |
1468 | } | |
1469 | ||
16aac5ad AG |
1470 | /* |
1471 | * Support encoding decodable file handles with nfs_export=on | |
1472 | * and encoding non-decodable file handles with nfs_export=off | |
1473 | * if all layers support file handles. | |
1474 | */ | |
8383f174 AG |
1475 | if (ofs->config.nfs_export) |
1476 | sb->s_export_op = &ovl_export_operations; | |
16aac5ad AG |
1477 | else if (!ofs->nofh) |
1478 | sb->s_export_op = &ovl_export_fid_operations; | |
8383f174 | 1479 | |
51f8f3c4 KK |
1480 | /* Never override disk quota limits or use reserved space */ |
1481 | cap_lower(cred->cap_effective, CAP_SYS_RESOURCE); | |
1482 | ||
655042cc | 1483 | sb->s_magic = OVERLAYFS_SUPER_MAGIC; |
2d2f2d73 MS |
1484 | sb->s_xattr = ofs->config.userxattr ? ovl_user_xattr_handlers : |
1485 | ovl_trusted_xattr_handlers; | |
ad204488 | 1486 | sb->s_fs_info = ofs; |
7c4d37c2 | 1487 | sb->s_flags |= SB_POSIXACL; |
18b44bc5 | 1488 | sb->s_iflags |= SB_I_SKIP_SYNC | SB_I_IMA_UNVERIFIABLE_SIGNATURE; |
655042cc | 1489 | |
c6fe6254 | 1490 | err = -ENOMEM; |
b36a5780 | 1491 | root_dentry = ovl_get_root(sb, ctx->upper.dentry, oe); |
e9be9d5e | 1492 | if (!root_dentry) |
4155c10a | 1493 | goto out_free_oe; |
e9be9d5e | 1494 | |
e9be9d5e | 1495 | sb->s_root = root_dentry; |
e9be9d5e MS |
1496 | |
1497 | return 0; | |
1498 | ||
4155c10a | 1499 | out_free_oe: |
163db0da | 1500 | ovl_free_entry(oe); |
4155c10a | 1501 | out_err: |
ad204488 | 1502 | ovl_free_fs(ofs); |
1784fbc2 | 1503 | sb->s_fs_info = NULL; |
e9be9d5e MS |
1504 | return err; |
1505 | } | |
1506 | ||
f01d0889 | 1507 | struct file_system_type ovl_fs_type = { |
1784fbc2 CB |
1508 | .owner = THIS_MODULE, |
1509 | .name = "overlay", | |
1510 | .init_fs_context = ovl_init_fs_context, | |
1511 | .parameters = ovl_parameter_spec, | |
1512 | .fs_flags = FS_USERNS_MOUNT, | |
1513 | .kill_sb = kill_anon_super, | |
e9be9d5e | 1514 | }; |
ef94b186 | 1515 | MODULE_ALIAS_FS("overlay"); |
e9be9d5e | 1516 | |
13cf199d AG |
1517 | static void ovl_inode_init_once(void *foo) |
1518 | { | |
1519 | struct ovl_inode *oi = foo; | |
1520 | ||
1521 | inode_init_once(&oi->vfs_inode); | |
1522 | } | |
1523 | ||
e9be9d5e MS |
1524 | static int __init ovl_init(void) |
1525 | { | |
13cf199d AG |
1526 | int err; |
1527 | ||
1528 | ovl_inode_cachep = kmem_cache_create("ovl_inode", | |
1529 | sizeof(struct ovl_inode), 0, | |
1530 | (SLAB_RECLAIM_ACCOUNT| | |
1531 | SLAB_MEM_SPREAD|SLAB_ACCOUNT), | |
1532 | ovl_inode_init_once); | |
1533 | if (ovl_inode_cachep == NULL) | |
1534 | return -ENOMEM; | |
1535 | ||
2406a307 JX |
1536 | err = ovl_aio_request_cache_init(); |
1537 | if (!err) { | |
1538 | err = register_filesystem(&ovl_fs_type); | |
1539 | if (!err) | |
1540 | return 0; | |
1541 | ||
1542 | ovl_aio_request_cache_destroy(); | |
1543 | } | |
1544 | kmem_cache_destroy(ovl_inode_cachep); | |
13cf199d AG |
1545 | |
1546 | return err; | |
e9be9d5e MS |
1547 | } |
1548 | ||
1549 | static void __exit ovl_exit(void) | |
1550 | { | |
1551 | unregister_filesystem(&ovl_fs_type); | |
13cf199d AG |
1552 | |
1553 | /* | |
1554 | * Make sure all delayed rcu free inodes are flushed before we | |
1555 | * destroy cache. | |
1556 | */ | |
1557 | rcu_barrier(); | |
1558 | kmem_cache_destroy(ovl_inode_cachep); | |
2406a307 | 1559 | ovl_aio_request_cache_destroy(); |
e9be9d5e MS |
1560 | } |
1561 | ||
1562 | module_init(ovl_init); | |
1563 | module_exit(ovl_exit); |