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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 | { |
a6ff2bc0 | 107 | struct ovl_entry *oe = OVL_E(dentry); |
5522c9c7 | 108 | struct ovl_path *lowerstack = ovl_lowerstack(oe); |
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 | ||
118 | upper = ovl_i_dentry_upper(inode); | |
bccece1e MS |
119 | if (upper) |
120 | ret = ovl_revalidate_real(upper, flags, weak); | |
121 | ||
5522c9c7 AG |
122 | for (i = 0; ret > 0 && i < ovl_numlower(oe); i++) |
123 | ret = ovl_revalidate_real(lowerstack[i].dentry, flags, weak); | |
124 | ||
7c03b5d4 MS |
125 | return ret; |
126 | } | |
127 | ||
3bb7df92 MS |
128 | static int ovl_dentry_revalidate(struct dentry *dentry, unsigned int flags) |
129 | { | |
130 | return ovl_dentry_revalidate_common(dentry, flags, false); | |
131 | } | |
132 | ||
133 | static int ovl_dentry_weak_revalidate(struct dentry *dentry, unsigned int flags) | |
134 | { | |
135 | return ovl_dentry_revalidate_common(dentry, flags, true); | |
136 | } | |
137 | ||
e9be9d5e | 138 | static const struct dentry_operations ovl_dentry_operations = { |
d101a125 | 139 | .d_real = ovl_d_real, |
7c03b5d4 MS |
140 | .d_revalidate = ovl_dentry_revalidate, |
141 | .d_weak_revalidate = ovl_dentry_weak_revalidate, | |
142 | }; | |
143 | ||
13cf199d AG |
144 | static struct kmem_cache *ovl_inode_cachep; |
145 | ||
146 | static struct inode *ovl_alloc_inode(struct super_block *sb) | |
147 | { | |
fd60b288 | 148 | struct ovl_inode *oi = alloc_inode_sb(sb, ovl_inode_cachep, GFP_KERNEL); |
13cf199d | 149 | |
b3885bd6 HN |
150 | if (!oi) |
151 | return NULL; | |
152 | ||
04a01ac7 | 153 | oi->cache = NULL; |
cf31c463 | 154 | oi->redirect = NULL; |
04a01ac7 | 155 | oi->version = 0; |
13c72075 | 156 | oi->flags = 0; |
09d8b586 | 157 | oi->__upperdentry = NULL; |
2b21da92 | 158 | oi->lowerdata_redirect = NULL; |
0af950f5 | 159 | oi->oe = NULL; |
a015dafc | 160 | mutex_init(&oi->lock); |
25b7713a | 161 | |
13cf199d AG |
162 | return &oi->vfs_inode; |
163 | } | |
164 | ||
0b269ded | 165 | static void ovl_free_inode(struct inode *inode) |
13cf199d | 166 | { |
0b269ded | 167 | struct ovl_inode *oi = OVL_I(inode); |
13cf199d | 168 | |
0b269ded AV |
169 | kfree(oi->redirect); |
170 | mutex_destroy(&oi->lock); | |
171 | kmem_cache_free(ovl_inode_cachep, oi); | |
13cf199d AG |
172 | } |
173 | ||
174 | static void ovl_destroy_inode(struct inode *inode) | |
175 | { | |
09d8b586 MS |
176 | struct ovl_inode *oi = OVL_I(inode); |
177 | ||
178 | dput(oi->__upperdentry); | |
0af950f5 | 179 | ovl_free_entry(oi->oe); |
2664bd08 VG |
180 | if (S_ISDIR(inode->i_mode)) |
181 | ovl_dir_cache_free(inode); | |
2b21da92 AG |
182 | else |
183 | kfree(oi->lowerdata_redirect); | |
13cf199d AG |
184 | } |
185 | ||
a9075cdb MS |
186 | static void ovl_put_super(struct super_block *sb) |
187 | { | |
f01d0889 | 188 | struct ovl_fs *ofs = OVL_FS(sb); |
a9075cdb | 189 | |
1784fbc2 CB |
190 | if (ofs) |
191 | ovl_free_fs(ofs); | |
a9075cdb MS |
192 | } |
193 | ||
e8d4bfe3 | 194 | /* Sync real dirty inodes in upper filesystem (if it exists) */ |
e593b2bf AG |
195 | static int ovl_sync_fs(struct super_block *sb, int wait) |
196 | { | |
f01d0889 | 197 | struct ovl_fs *ofs = OVL_FS(sb); |
e593b2bf AG |
198 | struct super_block *upper_sb; |
199 | int ret; | |
200 | ||
335d3fc5 SD |
201 | ret = ovl_sync_status(ofs); |
202 | /* | |
203 | * We have to always set the err, because the return value isn't | |
204 | * checked in syncfs, and instead indirectly return an error via | |
205 | * the sb's writeback errseq, which VFS inspects after this call. | |
206 | */ | |
207 | if (ret < 0) { | |
208 | errseq_set(&sb->s_wb_err, -EIO); | |
209 | return -EIO; | |
210 | } | |
211 | ||
212 | if (!ret) | |
213 | return ret; | |
e8d4bfe3 CX |
214 | |
215 | /* | |
32b1924b KK |
216 | * Not called for sync(2) call or an emergency sync (SB_I_SKIP_SYNC). |
217 | * All the super blocks will be iterated, including upper_sb. | |
e8d4bfe3 CX |
218 | * |
219 | * If this is a syncfs(2) call, then we do need to call | |
220 | * sync_filesystem() on upper_sb, but enough if we do it when being | |
221 | * called with wait == 1. | |
222 | */ | |
223 | if (!wait) | |
e593b2bf AG |
224 | return 0; |
225 | ||
08f4c7c8 | 226 | upper_sb = ovl_upper_mnt(ofs)->mnt_sb; |
e8d4bfe3 | 227 | |
e593b2bf | 228 | down_read(&upper_sb->s_umount); |
e8d4bfe3 | 229 | ret = sync_filesystem(upper_sb); |
e593b2bf | 230 | up_read(&upper_sb->s_umount); |
e8d4bfe3 | 231 | |
e593b2bf AG |
232 | return ret; |
233 | } | |
234 | ||
cc259639 AW |
235 | /** |
236 | * ovl_statfs | |
9c5dd803 | 237 | * @dentry: The dentry to query |
cc259639 AW |
238 | * @buf: The struct kstatfs to fill in with stats |
239 | * | |
240 | * Get the filesystem statistics. As writes always target the upper layer | |
4ebc5818 | 241 | * filesystem pass the statfs to the upper filesystem (if it exists) |
cc259639 AW |
242 | */ |
243 | static int ovl_statfs(struct dentry *dentry, struct kstatfs *buf) | |
244 | { | |
b0504bfe AG |
245 | struct super_block *sb = dentry->d_sb; |
246 | struct ovl_fs *ofs = OVL_FS(sb); | |
247 | struct dentry *root_dentry = sb->s_root; | |
cc259639 AW |
248 | struct path path; |
249 | int err; | |
250 | ||
4ebc5818 | 251 | ovl_path_real(root_dentry, &path); |
cc259639 AW |
252 | |
253 | err = vfs_statfs(&path, buf); | |
254 | if (!err) { | |
6b2d5fe4 | 255 | buf->f_namelen = ofs->namelen; |
cc259639 | 256 | buf->f_type = OVERLAYFS_SUPER_MAGIC; |
b0504bfe AG |
257 | if (ovl_has_fsid(ofs)) |
258 | buf->f_fsid = uuid_to_fsid(sb->s_uuid.b); | |
cc259639 AW |
259 | } |
260 | ||
261 | return err; | |
262 | } | |
263 | ||
e9be9d5e | 264 | static const struct super_operations ovl_super_operations = { |
13cf199d | 265 | .alloc_inode = ovl_alloc_inode, |
0b269ded | 266 | .free_inode = ovl_free_inode, |
13cf199d AG |
267 | .destroy_inode = ovl_destroy_inode, |
268 | .drop_inode = generic_delete_inode, | |
e9be9d5e | 269 | .put_super = ovl_put_super, |
e593b2bf | 270 | .sync_fs = ovl_sync_fs, |
cc259639 | 271 | .statfs = ovl_statfs, |
f45827e8 | 272 | .show_options = ovl_show_options, |
e9be9d5e MS |
273 | }; |
274 | ||
e9be9d5e | 275 | #define OVL_WORKDIR_NAME "work" |
02bcd157 | 276 | #define OVL_INDEXDIR_NAME "index" |
e9be9d5e | 277 | |
ad204488 | 278 | static struct dentry *ovl_workdir_create(struct ovl_fs *ofs, |
6b8aa129 | 279 | const char *name, bool persist) |
e9be9d5e | 280 | { |
ad204488 | 281 | struct inode *dir = ofs->workbasedir->d_inode; |
08f4c7c8 | 282 | struct vfsmount *mnt = ovl_upper_mnt(ofs); |
e9be9d5e MS |
283 | struct dentry *work; |
284 | int err; | |
285 | bool retried = false; | |
286 | ||
5955102c | 287 | inode_lock_nested(dir, I_MUTEX_PARENT); |
e9be9d5e | 288 | retry: |
22f289ce | 289 | work = ovl_lookup_upper(ofs, name, ofs->workbasedir, strlen(name)); |
e9be9d5e MS |
290 | |
291 | if (!IS_ERR(work)) { | |
c11b9fdd MS |
292 | struct iattr attr = { |
293 | .ia_valid = ATTR_MODE, | |
32a3d848 | 294 | .ia_mode = S_IFDIR | 0, |
c11b9fdd | 295 | }; |
e9be9d5e MS |
296 | |
297 | if (work->d_inode) { | |
298 | err = -EEXIST; | |
299 | if (retried) | |
300 | goto out_dput; | |
301 | ||
6b8aa129 AG |
302 | if (persist) |
303 | goto out_unlock; | |
304 | ||
e9be9d5e | 305 | retried = true; |
576bb263 | 306 | err = ovl_workdir_cleanup(ofs, dir, mnt, work, 0); |
e9be9d5e | 307 | dput(work); |
235ce9ed AG |
308 | if (err == -EINVAL) { |
309 | work = ERR_PTR(err); | |
310 | goto out_unlock; | |
311 | } | |
e9be9d5e MS |
312 | goto retry; |
313 | } | |
314 | ||
576bb263 | 315 | err = ovl_mkdir_real(ofs, dir, &work, attr.ia_mode); |
1f5573cf MS |
316 | if (err) |
317 | goto out_dput; | |
318 | ||
319 | /* Weird filesystem returning with hashed negative (kernfs)? */ | |
320 | err = -EINVAL; | |
321 | if (d_really_is_negative(work)) | |
322 | goto out_dput; | |
c11b9fdd | 323 | |
cb348edb MS |
324 | /* |
325 | * Try to remove POSIX ACL xattrs from workdir. We are good if: | |
326 | * | |
327 | * a) success (there was a POSIX ACL xattr and was removed) | |
328 | * b) -ENODATA (there was no POSIX ACL xattr) | |
329 | * c) -EOPNOTSUPP (POSIX ACL xattrs are not supported) | |
330 | * | |
331 | * There are various other error values that could effectively | |
332 | * mean that the xattr doesn't exist (e.g. -ERANGE is returned | |
333 | * if the xattr name is too long), but the set of filesystems | |
334 | * allowed as upper are limited to "normal" ones, where checking | |
335 | * for the above two errors is sufficient. | |
336 | */ | |
31acceb9 | 337 | err = ovl_do_remove_acl(ofs, work, XATTR_NAME_POSIX_ACL_DEFAULT); |
e1ff3dd1 | 338 | if (err && err != -ENODATA && err != -EOPNOTSUPP) |
c11b9fdd MS |
339 | goto out_dput; |
340 | ||
31acceb9 | 341 | err = ovl_do_remove_acl(ofs, work, XATTR_NAME_POSIX_ACL_ACCESS); |
e1ff3dd1 | 342 | if (err && err != -ENODATA && err != -EOPNOTSUPP) |
c11b9fdd MS |
343 | goto out_dput; |
344 | ||
345 | /* Clear any inherited mode bits */ | |
346 | inode_lock(work->d_inode); | |
a15506ea | 347 | err = ovl_do_notify_change(ofs, work, &attr); |
c11b9fdd MS |
348 | inode_unlock(work->d_inode); |
349 | if (err) | |
350 | goto out_dput; | |
6b8aa129 AG |
351 | } else { |
352 | err = PTR_ERR(work); | |
353 | goto out_err; | |
e9be9d5e MS |
354 | } |
355 | out_unlock: | |
2068cf7d | 356 | inode_unlock(dir); |
e9be9d5e MS |
357 | return work; |
358 | ||
359 | out_dput: | |
360 | dput(work); | |
6b8aa129 | 361 | out_err: |
1bd0a3ae | 362 | pr_warn("failed to create directory %s/%s (errno: %i); mounting read-only\n", |
ad204488 | 363 | ofs->config.workdir, name, -err); |
6b8aa129 | 364 | work = NULL; |
e9be9d5e MS |
365 | goto out_unlock; |
366 | } | |
367 | ||
2d343087 | 368 | static int ovl_check_namelen(const struct path *path, struct ovl_fs *ofs, |
6b2d5fe4 | 369 | const char *name) |
ab508822 | 370 | { |
ab508822 | 371 | struct kstatfs statfs; |
6b2d5fe4 MS |
372 | int err = vfs_statfs(path, &statfs); |
373 | ||
374 | if (err) | |
1bd0a3ae | 375 | pr_err("statfs failed on '%s'\n", name); |
6b2d5fe4 MS |
376 | else |
377 | ofs->namelen = max(ofs->namelen, statfs.f_namelen); | |
378 | ||
379 | return err; | |
380 | } | |
381 | ||
382 | static int ovl_lower_dir(const char *name, struct path *path, | |
f4288844 | 383 | struct ovl_fs *ofs, int *stack_depth) |
6b2d5fe4 | 384 | { |
e487d889 | 385 | int fh_type; |
6b2d5fe4 | 386 | int err; |
ab508822 | 387 | |
6b2d5fe4 MS |
388 | err = ovl_check_namelen(path, ofs, name); |
389 | if (err) | |
b8e42a65 | 390 | return err; |
6b2d5fe4 | 391 | |
ab508822 MS |
392 | *stack_depth = max(*stack_depth, path->mnt->mnt_sb->s_stack_depth); |
393 | ||
02bcd157 | 394 | /* |
f168f109 AG |
395 | * The inodes index feature and NFS export need to encode and decode |
396 | * file handles, so they require that all layers support them. | |
02bcd157 | 397 | */ |
e487d889 | 398 | fh_type = ovl_can_decode_fh(path->dentry->d_sb); |
f168f109 | 399 | if ((ofs->config.nfs_export || |
e487d889 | 400 | (ofs->config.index && ofs->config.upperdir)) && !fh_type) { |
02bcd157 | 401 | ofs->config.index = false; |
f168f109 | 402 | ofs->config.nfs_export = false; |
1bd0a3ae | 403 | pr_warn("fs on '%s' does not support file handles, falling back to index=off,nfs_export=off.\n", |
f168f109 | 404 | name); |
02bcd157 | 405 | } |
16aac5ad | 406 | ofs->nofh |= !fh_type; |
b0e0f697 AG |
407 | /* |
408 | * Decoding origin file handle is required for persistent st_ino. | |
409 | * Without persistent st_ino, xino=auto falls back to xino=off. | |
410 | */ | |
411 | if (ofs->config.xino == OVL_XINO_AUTO && | |
412 | ofs->config.upperdir && !fh_type) { | |
413 | ofs->config.xino = OVL_XINO_OFF; | |
414 | pr_warn("fs on '%s' does not support file handles, falling back to xino=off.\n", | |
415 | name); | |
416 | } | |
02bcd157 | 417 | |
e487d889 AG |
418 | /* Check if lower fs has 32bit inode numbers */ |
419 | if (fh_type != FILEID_INO32_GEN) | |
0f831ec8 | 420 | ofs->xino_mode = -1; |
e487d889 | 421 | |
ab508822 | 422 | return 0; |
ab508822 MS |
423 | } |
424 | ||
e9be9d5e MS |
425 | /* Workdir should not be subdir of upperdir and vice versa */ |
426 | static bool ovl_workdir_ok(struct dentry *workdir, struct dentry *upperdir) | |
427 | { | |
428 | bool ok = false; | |
429 | ||
430 | if (workdir != upperdir) { | |
431 | ok = (lock_rename(workdir, upperdir) == NULL); | |
432 | unlock_rename(workdir, upperdir); | |
433 | } | |
434 | return ok; | |
435 | } | |
436 | ||
0eb45fc3 AG |
437 | static int ovl_own_xattr_get(const struct xattr_handler *handler, |
438 | struct dentry *dentry, struct inode *inode, | |
439 | const char *name, void *buffer, size_t size) | |
440 | { | |
48fab5d7 | 441 | return -EOPNOTSUPP; |
0eb45fc3 AG |
442 | } |
443 | ||
d837a49b | 444 | static int ovl_own_xattr_set(const struct xattr_handler *handler, |
39f60c1c | 445 | struct mnt_idmap *idmap, |
d837a49b MS |
446 | struct dentry *dentry, struct inode *inode, |
447 | const char *name, const void *value, | |
448 | size_t size, int flags) | |
449 | { | |
48fab5d7 | 450 | return -EOPNOTSUPP; |
d837a49b MS |
451 | } |
452 | ||
0eb45fc3 AG |
453 | static int ovl_other_xattr_get(const struct xattr_handler *handler, |
454 | struct dentry *dentry, struct inode *inode, | |
455 | const char *name, void *buffer, size_t size) | |
456 | { | |
1d88f183 | 457 | return ovl_xattr_get(dentry, inode, name, buffer, size); |
0eb45fc3 AG |
458 | } |
459 | ||
0e585ccc | 460 | static int ovl_other_xattr_set(const struct xattr_handler *handler, |
39f60c1c | 461 | struct mnt_idmap *idmap, |
0e585ccc AG |
462 | struct dentry *dentry, struct inode *inode, |
463 | const char *name, const void *value, | |
464 | size_t size, int flags) | |
465 | { | |
1d88f183 | 466 | return ovl_xattr_set(dentry, inode, name, value, size, flags); |
0e585ccc AG |
467 | } |
468 | ||
2d2f2d73 MS |
469 | static const struct xattr_handler ovl_own_trusted_xattr_handler = { |
470 | .prefix = OVL_XATTR_TRUSTED_PREFIX, | |
471 | .get = ovl_own_xattr_get, | |
472 | .set = ovl_own_xattr_set, | |
473 | }; | |
474 | ||
475 | static const struct xattr_handler ovl_own_user_xattr_handler = { | |
476 | .prefix = OVL_XATTR_USER_PREFIX, | |
0eb45fc3 | 477 | .get = ovl_own_xattr_get, |
d837a49b MS |
478 | .set = ovl_own_xattr_set, |
479 | }; | |
480 | ||
481 | static const struct xattr_handler ovl_other_xattr_handler = { | |
482 | .prefix = "", /* catch all */ | |
0eb45fc3 | 483 | .get = ovl_other_xattr_get, |
d837a49b MS |
484 | .set = ovl_other_xattr_set, |
485 | }; | |
486 | ||
2d2f2d73 | 487 | static const struct xattr_handler *ovl_trusted_xattr_handlers[] = { |
2d2f2d73 MS |
488 | &ovl_own_trusted_xattr_handler, |
489 | &ovl_other_xattr_handler, | |
490 | NULL | |
491 | }; | |
492 | ||
493 | static const struct xattr_handler *ovl_user_xattr_handlers[] = { | |
2d2f2d73 | 494 | &ovl_own_user_xattr_handler, |
d837a49b MS |
495 | &ovl_other_xattr_handler, |
496 | NULL | |
497 | }; | |
498 | ||
146d62e5 AG |
499 | static int ovl_setup_trap(struct super_block *sb, struct dentry *dir, |
500 | struct inode **ptrap, const char *name) | |
501 | { | |
502 | struct inode *trap; | |
503 | int err; | |
504 | ||
505 | trap = ovl_get_trap_inode(sb, dir); | |
1dac6f5b AB |
506 | err = PTR_ERR_OR_ZERO(trap); |
507 | if (err) { | |
146d62e5 | 508 | if (err == -ELOOP) |
1bd0a3ae | 509 | pr_err("conflicting %s path\n", name); |
146d62e5 AG |
510 | return err; |
511 | } | |
512 | ||
513 | *ptrap = trap; | |
514 | return 0; | |
515 | } | |
516 | ||
0be0bfd2 AG |
517 | /* |
518 | * Determine how we treat concurrent use of upperdir/workdir based on the | |
519 | * index feature. This is papering over mount leaks of container runtimes, | |
520 | * for example, an old overlay mount is leaked and now its upperdir is | |
521 | * attempted to be used as a lower layer in a new overlay mount. | |
522 | */ | |
523 | static int ovl_report_in_use(struct ovl_fs *ofs, const char *name) | |
524 | { | |
525 | if (ofs->config.index) { | |
1bd0a3ae | 526 | 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 |
527 | name); |
528 | return -EBUSY; | |
529 | } else { | |
1bd0a3ae | 530 | 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 |
531 | name); |
532 | return 0; | |
533 | } | |
534 | } | |
535 | ||
146d62e5 | 536 | static int ovl_get_upper(struct super_block *sb, struct ovl_fs *ofs, |
b36a5780 CB |
537 | struct ovl_layer *upper_layer, |
538 | const struct path *upperpath) | |
6ee8acf0 | 539 | { |
5064975e | 540 | struct vfsmount *upper_mnt; |
6ee8acf0 MS |
541 | int err; |
542 | ||
e21a6c57 AG |
543 | /* Upperdir path should not be r/o */ |
544 | if (__mnt_is_readonly(upperpath->mnt)) { | |
1bd0a3ae | 545 | pr_err("upper fs is r/o, try multi-lower layers mount\n"); |
6ee8acf0 MS |
546 | err = -EINVAL; |
547 | goto out; | |
548 | } | |
549 | ||
ad204488 | 550 | err = ovl_check_namelen(upperpath, ofs, ofs->config.upperdir); |
6ee8acf0 MS |
551 | if (err) |
552 | goto out; | |
553 | ||
b8e42a65 | 554 | err = ovl_setup_trap(sb, upperpath->dentry, &upper_layer->trap, |
146d62e5 AG |
555 | "upperdir"); |
556 | if (err) | |
557 | goto out; | |
558 | ||
5064975e MS |
559 | upper_mnt = clone_private_mount(upperpath); |
560 | err = PTR_ERR(upper_mnt); | |
561 | if (IS_ERR(upper_mnt)) { | |
1bd0a3ae | 562 | pr_err("failed to clone upperpath\n"); |
5064975e MS |
563 | goto out; |
564 | } | |
565 | ||
566 | /* Don't inherit atime flags */ | |
567 | upper_mnt->mnt_flags &= ~(MNT_NOATIME | MNT_NODIRATIME | MNT_RELATIME); | |
b8e42a65 MS |
568 | upper_layer->mnt = upper_mnt; |
569 | upper_layer->idx = 0; | |
570 | upper_layer->fsid = 0; | |
8c25741a | 571 | |
b36a5780 CB |
572 | err = -ENOMEM; |
573 | upper_layer->name = kstrdup(ofs->config.upperdir, GFP_KERNEL); | |
574 | if (!upper_layer->name) | |
575 | goto out; | |
576 | ||
654255fa JX |
577 | /* |
578 | * Inherit SB_NOSEC flag from upperdir. | |
579 | * | |
580 | * This optimization changes behavior when a security related attribute | |
581 | * (suid/sgid/security.*) is changed on an underlying layer. This is | |
582 | * okay because we don't yet have guarantees in that case, but it will | |
583 | * need careful treatment once we want to honour changes to underlying | |
584 | * filesystems. | |
585 | */ | |
586 | if (upper_mnt->mnt_sb->s_flags & SB_NOSEC) | |
587 | sb->s_flags |= SB_NOSEC; | |
588 | ||
08f4c7c8 | 589 | if (ovl_inuse_trylock(ovl_upper_mnt(ofs)->mnt_root)) { |
8c25741a | 590 | ofs->upperdir_locked = true; |
8c25741a | 591 | } else { |
0be0bfd2 AG |
592 | err = ovl_report_in_use(ofs, "upperdir"); |
593 | if (err) | |
594 | goto out; | |
8c25741a MS |
595 | } |
596 | ||
6ee8acf0 MS |
597 | err = 0; |
598 | out: | |
599 | return err; | |
600 | } | |
601 | ||
cad218ab AG |
602 | /* |
603 | * Returns 1 if RENAME_WHITEOUT is supported, 0 if not supported and | |
604 | * negative values if error is encountered. | |
605 | */ | |
576bb263 | 606 | static int ovl_check_rename_whiteout(struct ovl_fs *ofs) |
cad218ab | 607 | { |
576bb263 | 608 | struct dentry *workdir = ofs->workdir; |
cad218ab AG |
609 | struct inode *dir = d_inode(workdir); |
610 | struct dentry *temp; | |
611 | struct dentry *dest; | |
612 | struct dentry *whiteout; | |
613 | struct name_snapshot name; | |
614 | int err; | |
615 | ||
616 | inode_lock_nested(dir, I_MUTEX_PARENT); | |
617 | ||
576bb263 | 618 | temp = ovl_create_temp(ofs, workdir, OVL_CATTR(S_IFREG | 0)); |
cad218ab AG |
619 | err = PTR_ERR(temp); |
620 | if (IS_ERR(temp)) | |
621 | goto out_unlock; | |
622 | ||
576bb263 | 623 | dest = ovl_lookup_temp(ofs, workdir); |
cad218ab AG |
624 | err = PTR_ERR(dest); |
625 | if (IS_ERR(dest)) { | |
626 | dput(temp); | |
627 | goto out_unlock; | |
628 | } | |
629 | ||
630 | /* Name is inline and stable - using snapshot as a copy helper */ | |
631 | take_dentry_name_snapshot(&name, temp); | |
576bb263 | 632 | err = ovl_do_rename(ofs, dir, temp, dir, dest, RENAME_WHITEOUT); |
cad218ab AG |
633 | if (err) { |
634 | if (err == -EINVAL) | |
635 | err = 0; | |
636 | goto cleanup_temp; | |
637 | } | |
638 | ||
22f289ce | 639 | whiteout = ovl_lookup_upper(ofs, name.name.name, workdir, name.name.len); |
cad218ab AG |
640 | err = PTR_ERR(whiteout); |
641 | if (IS_ERR(whiteout)) | |
642 | goto cleanup_temp; | |
643 | ||
644 | err = ovl_is_whiteout(whiteout); | |
645 | ||
646 | /* Best effort cleanup of whiteout and temp file */ | |
647 | if (err) | |
576bb263 | 648 | ovl_cleanup(ofs, dir, whiteout); |
cad218ab AG |
649 | dput(whiteout); |
650 | ||
651 | cleanup_temp: | |
576bb263 | 652 | ovl_cleanup(ofs, dir, temp); |
cad218ab AG |
653 | release_dentry_name_snapshot(&name); |
654 | dput(temp); | |
655 | dput(dest); | |
656 | ||
657 | out_unlock: | |
658 | inode_unlock(dir); | |
659 | ||
660 | return err; | |
661 | } | |
662 | ||
576bb263 CB |
663 | static struct dentry *ovl_lookup_or_create(struct ovl_fs *ofs, |
664 | struct dentry *parent, | |
c86243b0 VG |
665 | const char *name, umode_t mode) |
666 | { | |
667 | size_t len = strlen(name); | |
668 | struct dentry *child; | |
669 | ||
670 | inode_lock_nested(parent->d_inode, I_MUTEX_PARENT); | |
22f289ce | 671 | child = ovl_lookup_upper(ofs, name, parent, len); |
c86243b0 | 672 | if (!IS_ERR(child) && !child->d_inode) |
576bb263 | 673 | child = ovl_create_real(ofs, parent->d_inode, child, |
c86243b0 VG |
674 | OVL_CATTR(mode)); |
675 | inode_unlock(parent->d_inode); | |
676 | dput(parent); | |
677 | ||
678 | return child; | |
679 | } | |
680 | ||
681 | /* | |
682 | * Creates $workdir/work/incompat/volatile/dirty file if it is not already | |
683 | * present. | |
684 | */ | |
685 | static int ovl_create_volatile_dirty(struct ovl_fs *ofs) | |
686 | { | |
687 | unsigned int ctr; | |
688 | struct dentry *d = dget(ofs->workbasedir); | |
689 | static const char *const volatile_path[] = { | |
690 | OVL_WORKDIR_NAME, "incompat", "volatile", "dirty" | |
691 | }; | |
692 | const char *const *name = volatile_path; | |
693 | ||
694 | for (ctr = ARRAY_SIZE(volatile_path); ctr; ctr--, name++) { | |
576bb263 | 695 | d = ovl_lookup_or_create(ofs, d, *name, ctr > 1 ? S_IFDIR : S_IFREG); |
c86243b0 VG |
696 | if (IS_ERR(d)) |
697 | return PTR_ERR(d); | |
698 | } | |
699 | dput(d); | |
700 | return 0; | |
701 | } | |
702 | ||
146d62e5 | 703 | static int ovl_make_workdir(struct super_block *sb, struct ovl_fs *ofs, |
2d343087 | 704 | const struct path *workpath) |
8ed61dc3 | 705 | { |
08f4c7c8 | 706 | struct vfsmount *mnt = ovl_upper_mnt(ofs); |
2b1a7746 MS |
707 | struct dentry *workdir; |
708 | struct file *tmpfile; | |
d80172c2 AG |
709 | bool rename_whiteout; |
710 | bool d_type; | |
e487d889 | 711 | int fh_type; |
8ed61dc3 MS |
712 | int err; |
713 | ||
2ba9d57e AG |
714 | err = mnt_want_write(mnt); |
715 | if (err) | |
716 | return err; | |
717 | ||
235ce9ed AG |
718 | workdir = ovl_workdir_create(ofs, OVL_WORKDIR_NAME, false); |
719 | err = PTR_ERR(workdir); | |
720 | if (IS_ERR_OR_NULL(workdir)) | |
2ba9d57e | 721 | goto out; |
8ed61dc3 | 722 | |
235ce9ed AG |
723 | ofs->workdir = workdir; |
724 | ||
146d62e5 AG |
725 | err = ovl_setup_trap(sb, ofs->workdir, &ofs->workdir_trap, "workdir"); |
726 | if (err) | |
727 | goto out; | |
728 | ||
8ed61dc3 MS |
729 | /* |
730 | * Upper should support d_type, else whiteouts are visible. Given | |
731 | * workdir and upper are on same fs, we can do iterate_dir() on | |
732 | * workdir. This check requires successful creation of workdir in | |
733 | * previous step. | |
734 | */ | |
735 | err = ovl_check_d_type_supported(workpath); | |
736 | if (err < 0) | |
2ba9d57e | 737 | goto out; |
8ed61dc3 | 738 | |
d80172c2 AG |
739 | d_type = err; |
740 | if (!d_type) | |
1bd0a3ae | 741 | pr_warn("upper fs needs to support d_type.\n"); |
8ed61dc3 MS |
742 | |
743 | /* Check if upper/work fs supports O_TMPFILE */ | |
2b1a7746 MS |
744 | tmpfile = ovl_do_tmpfile(ofs, ofs->workdir, S_IFREG | 0); |
745 | ofs->tmpfile = !IS_ERR(tmpfile); | |
ad204488 | 746 | if (ofs->tmpfile) |
2b1a7746 | 747 | fput(tmpfile); |
8ed61dc3 | 748 | else |
1bd0a3ae | 749 | pr_warn("upper fs does not support tmpfile.\n"); |
8ed61dc3 | 750 | |
cad218ab AG |
751 | |
752 | /* Check if upper/work fs supports RENAME_WHITEOUT */ | |
576bb263 | 753 | err = ovl_check_rename_whiteout(ofs); |
cad218ab AG |
754 | if (err < 0) |
755 | goto out; | |
756 | ||
d80172c2 AG |
757 | rename_whiteout = err; |
758 | if (!rename_whiteout) | |
cad218ab AG |
759 | pr_warn("upper fs does not support RENAME_WHITEOUT.\n"); |
760 | ||
8ed61dc3 | 761 | /* |
2d2f2d73 | 762 | * Check if upper/work fs supports (trusted|user).overlay.* xattr |
8ed61dc3 | 763 | */ |
c914c0e2 | 764 | err = ovl_setxattr(ofs, ofs->workdir, OVL_XATTR_OPAQUE, "0", 1); |
8ed61dc3 | 765 | if (err) { |
b10b85fe | 766 | pr_warn("failed to set xattr on upper\n"); |
ad204488 | 767 | ofs->noxattr = true; |
af5f2396 AG |
768 | if (ovl_redirect_follow(ofs)) { |
769 | ofs->config.redirect_mode = OVL_REDIRECT_NOFOLLOW; | |
770 | pr_warn("...falling back to redirect_dir=nofollow.\n"); | |
771 | } | |
772 | if (ofs->config.metacopy) { | |
b0e0f697 | 773 | ofs->config.metacopy = false; |
af5f2396 AG |
774 | pr_warn("...falling back to metacopy=off.\n"); |
775 | } | |
776 | if (ofs->config.index) { | |
777 | ofs->config.index = false; | |
778 | pr_warn("...falling back to index=off.\n"); | |
b0e0f697 | 779 | } |
d9544c1b AG |
780 | if (ovl_has_fsid(ofs)) { |
781 | ofs->config.uuid = OVL_UUID_NULL; | |
782 | pr_warn("...falling back to uuid=null.\n"); | |
783 | } | |
b0e0f697 AG |
784 | /* |
785 | * xattr support is required for persistent st_ino. | |
786 | * Without persistent st_ino, xino=auto falls back to xino=off. | |
787 | */ | |
788 | if (ofs->config.xino == OVL_XINO_AUTO) { | |
789 | ofs->config.xino = OVL_XINO_OFF; | |
b10b85fe | 790 | pr_warn("...falling back to xino=off.\n"); |
b0e0f697 | 791 | } |
b10b85fe MS |
792 | if (err == -EPERM && !ofs->config.userxattr) |
793 | pr_info("try mounting with 'userxattr' option\n"); | |
2ba9d57e | 794 | err = 0; |
8ed61dc3 | 795 | } else { |
c914c0e2 | 796 | ovl_removexattr(ofs, ofs->workdir, OVL_XATTR_OPAQUE); |
8ed61dc3 MS |
797 | } |
798 | ||
d80172c2 AG |
799 | /* |
800 | * We allowed sub-optimal upper fs configuration and don't want to break | |
801 | * users over kernel upgrade, but we never allowed remote upper fs, so | |
802 | * we can enforce strict requirements for remote upper fs. | |
803 | */ | |
804 | if (ovl_dentry_remote(ofs->workdir) && | |
805 | (!d_type || !rename_whiteout || ofs->noxattr)) { | |
806 | pr_err("upper fs missing required features.\n"); | |
807 | err = -EINVAL; | |
808 | goto out; | |
809 | } | |
810 | ||
c86243b0 VG |
811 | /* |
812 | * For volatile mount, create a incompat/volatile/dirty file to keep | |
813 | * track of it. | |
814 | */ | |
815 | if (ofs->config.ovl_volatile) { | |
816 | err = ovl_create_volatile_dirty(ofs); | |
817 | if (err < 0) { | |
818 | pr_err("Failed to create volatile/dirty file.\n"); | |
819 | goto out; | |
820 | } | |
821 | } | |
822 | ||
8ed61dc3 | 823 | /* Check if upper/work fs supports file handles */ |
e487d889 AG |
824 | fh_type = ovl_can_decode_fh(ofs->workdir->d_sb); |
825 | if (ofs->config.index && !fh_type) { | |
ad204488 | 826 | ofs->config.index = false; |
1bd0a3ae | 827 | pr_warn("upper fs does not support file handles, falling back to index=off.\n"); |
8ed61dc3 | 828 | } |
16aac5ad | 829 | ofs->nofh |= !fh_type; |
8ed61dc3 | 830 | |
e487d889 AG |
831 | /* Check if upper fs has 32bit inode numbers */ |
832 | if (fh_type != FILEID_INO32_GEN) | |
0f831ec8 | 833 | ofs->xino_mode = -1; |
e487d889 | 834 | |
f168f109 AG |
835 | /* NFS export of r/w mount depends on index */ |
836 | if (ofs->config.nfs_export && !ofs->config.index) { | |
1bd0a3ae | 837 | pr_warn("NFS export requires \"index=on\", falling back to nfs_export=off.\n"); |
f168f109 AG |
838 | ofs->config.nfs_export = false; |
839 | } | |
2ba9d57e AG |
840 | out: |
841 | mnt_drop_write(mnt); | |
842 | return err; | |
8ed61dc3 MS |
843 | } |
844 | ||
146d62e5 | 845 | static int ovl_get_workdir(struct super_block *sb, struct ovl_fs *ofs, |
b36a5780 CB |
846 | const struct path *upperpath, |
847 | const struct path *workpath) | |
520d7c86 MS |
848 | { |
849 | int err; | |
520d7c86 MS |
850 | |
851 | err = -EINVAL; | |
b36a5780 | 852 | if (upperpath->mnt != workpath->mnt) { |
1bd0a3ae | 853 | pr_err("workdir and upperdir must reside under the same mount\n"); |
b36a5780 | 854 | return err; |
520d7c86 | 855 | } |
b36a5780 | 856 | if (!ovl_workdir_ok(workpath->dentry, upperpath->dentry)) { |
1bd0a3ae | 857 | pr_err("workdir and upperdir must be separate subtrees\n"); |
b36a5780 | 858 | return err; |
520d7c86 MS |
859 | } |
860 | ||
b36a5780 | 861 | ofs->workbasedir = dget(workpath->dentry); |
8c25741a | 862 | |
8c25741a | 863 | if (ovl_inuse_trylock(ofs->workbasedir)) { |
ad204488 | 864 | ofs->workdir_locked = true; |
520d7c86 | 865 | } else { |
0be0bfd2 AG |
866 | err = ovl_report_in_use(ofs, "workdir"); |
867 | if (err) | |
b36a5780 | 868 | return err; |
520d7c86 MS |
869 | } |
870 | ||
0be0bfd2 AG |
871 | err = ovl_setup_trap(sb, ofs->workbasedir, &ofs->workbasedir_trap, |
872 | "workdir"); | |
873 | if (err) | |
b36a5780 | 874 | return err; |
bca44b52 | 875 | |
b36a5780 | 876 | return ovl_make_workdir(sb, ofs, workpath); |
520d7c86 MS |
877 | } |
878 | ||
146d62e5 | 879 | static int ovl_get_indexdir(struct super_block *sb, struct ovl_fs *ofs, |
2d343087 | 880 | struct ovl_entry *oe, const struct path *upperpath) |
f7e3a7d9 | 881 | { |
08f4c7c8 | 882 | struct vfsmount *mnt = ovl_upper_mnt(ofs); |
235ce9ed | 883 | struct dentry *indexdir; |
f7e3a7d9 MS |
884 | int err; |
885 | ||
2ba9d57e AG |
886 | err = mnt_want_write(mnt); |
887 | if (err) | |
888 | return err; | |
889 | ||
f7e3a7d9 | 890 | /* Verify lower root is upper root origin */ |
610afc0b | 891 | err = ovl_verify_origin(ofs, upperpath->dentry, |
5522c9c7 | 892 | ovl_lowerstack(oe)->dentry, true); |
f7e3a7d9 | 893 | if (err) { |
1bd0a3ae | 894 | pr_err("failed to verify upper root origin\n"); |
f7e3a7d9 MS |
895 | goto out; |
896 | } | |
897 | ||
470c1563 AG |
898 | /* index dir will act also as workdir */ |
899 | iput(ofs->workdir_trap); | |
900 | ofs->workdir_trap = NULL; | |
901 | dput(ofs->workdir); | |
902 | ofs->workdir = NULL; | |
235ce9ed AG |
903 | indexdir = ovl_workdir_create(ofs, OVL_INDEXDIR_NAME, true); |
904 | if (IS_ERR(indexdir)) { | |
905 | err = PTR_ERR(indexdir); | |
906 | } else if (indexdir) { | |
907 | ofs->indexdir = indexdir; | |
908 | ofs->workdir = dget(indexdir); | |
20396365 | 909 | |
146d62e5 AG |
910 | err = ovl_setup_trap(sb, ofs->indexdir, &ofs->indexdir_trap, |
911 | "indexdir"); | |
912 | if (err) | |
913 | goto out; | |
914 | ||
ad1d615c AG |
915 | /* |
916 | * Verify upper root is exclusively associated with index dir. | |
2d2f2d73 | 917 | * Older kernels stored upper fh in ".overlay.origin" |
ad1d615c AG |
918 | * xattr. If that xattr exists, verify that it is a match to |
919 | * upper dir file handle. In any case, verify or set xattr | |
2d2f2d73 | 920 | * ".overlay.upper" to indicate that index may have |
ad1d615c AG |
921 | * directory entries. |
922 | */ | |
610afc0b MS |
923 | if (ovl_check_origin_xattr(ofs, ofs->indexdir)) { |
924 | err = ovl_verify_set_fh(ofs, ofs->indexdir, | |
925 | OVL_XATTR_ORIGIN, | |
ad1d615c AG |
926 | upperpath->dentry, true, false); |
927 | if (err) | |
1bd0a3ae | 928 | pr_err("failed to verify index dir 'origin' xattr\n"); |
ad1d615c | 929 | } |
610afc0b MS |
930 | err = ovl_verify_upper(ofs, ofs->indexdir, upperpath->dentry, |
931 | true); | |
f7e3a7d9 | 932 | if (err) |
1bd0a3ae | 933 | pr_err("failed to verify index dir 'upper' xattr\n"); |
f7e3a7d9 MS |
934 | |
935 | /* Cleanup bad/stale/orphan index entries */ | |
936 | if (!err) | |
1eff1a1d | 937 | err = ovl_indexdir_cleanup(ofs); |
f7e3a7d9 | 938 | } |
ad204488 | 939 | if (err || !ofs->indexdir) |
1bd0a3ae | 940 | pr_warn("try deleting index dir or mounting with '-o index=off' to disable inodes index.\n"); |
f7e3a7d9 MS |
941 | |
942 | out: | |
2ba9d57e | 943 | mnt_drop_write(mnt); |
f7e3a7d9 MS |
944 | return err; |
945 | } | |
946 | ||
9df085f3 AG |
947 | static bool ovl_lower_uuid_ok(struct ovl_fs *ofs, const uuid_t *uuid) |
948 | { | |
949 | unsigned int i; | |
950 | ||
08f4c7c8 | 951 | if (!ofs->config.nfs_export && !ovl_upper_mnt(ofs)) |
9df085f3 AG |
952 | return true; |
953 | ||
a888db31 AG |
954 | /* |
955 | * We allow using single lower with null uuid for index and nfs_export | |
956 | * for example to support those features with single lower squashfs. | |
957 | * To avoid regressions in setups of overlay with re-formatted lower | |
958 | * squashfs, do not allow decoding origin with lower null uuid unless | |
959 | * user opted-in to one of the new features that require following the | |
960 | * lower inode of non-dir upper. | |
961 | */ | |
ca45275c | 962 | if (ovl_allow_offline_changes(ofs) && uuid_is_null(uuid)) |
a888db31 AG |
963 | return false; |
964 | ||
1b81dddd | 965 | for (i = 0; i < ofs->numfs; i++) { |
9df085f3 AG |
966 | /* |
967 | * We use uuid to associate an overlay lower file handle with a | |
968 | * lower layer, so we can accept lower fs with null uuid as long | |
969 | * as all lower layers with null uuid are on the same fs. | |
7e63c87f AG |
970 | * if we detect multiple lower fs with the same uuid, we |
971 | * disable lower file handle decoding on all of them. | |
9df085f3 | 972 | */ |
1b81dddd AG |
973 | if (ofs->fs[i].is_lower && |
974 | uuid_equal(&ofs->fs[i].sb->s_uuid, uuid)) { | |
07f1e596 | 975 | ofs->fs[i].bad_uuid = true; |
9df085f3 | 976 | return false; |
7e63c87f | 977 | } |
9df085f3 AG |
978 | } |
979 | return true; | |
980 | } | |
981 | ||
5148626b | 982 | /* Get a unique fsid for the layer */ |
9df085f3 | 983 | static int ovl_get_fsid(struct ovl_fs *ofs, const struct path *path) |
5148626b | 984 | { |
9df085f3 | 985 | struct super_block *sb = path->mnt->mnt_sb; |
5148626b AG |
986 | unsigned int i; |
987 | dev_t dev; | |
988 | int err; | |
7e63c87f | 989 | bool bad_uuid = false; |
b0e0f697 | 990 | bool warn = false; |
5148626b | 991 | |
07f1e596 AG |
992 | for (i = 0; i < ofs->numfs; i++) { |
993 | if (ofs->fs[i].sb == sb) | |
994 | return i; | |
5148626b AG |
995 | } |
996 | ||
9df085f3 | 997 | if (!ovl_lower_uuid_ok(ofs, &sb->s_uuid)) { |
7e63c87f | 998 | bad_uuid = true; |
b0e0f697 AG |
999 | if (ofs->config.xino == OVL_XINO_AUTO) { |
1000 | ofs->config.xino = OVL_XINO_OFF; | |
1001 | warn = true; | |
1002 | } | |
7e63c87f AG |
1003 | if (ofs->config.index || ofs->config.nfs_export) { |
1004 | ofs->config.index = false; | |
1005 | ofs->config.nfs_export = false; | |
b0e0f697 AG |
1006 | warn = true; |
1007 | } | |
1008 | if (warn) { | |
1009 | pr_warn("%s uuid detected in lower fs '%pd2', falling back to xino=%s,index=off,nfs_export=off.\n", | |
7e63c87f AG |
1010 | uuid_is_null(&sb->s_uuid) ? "null" : |
1011 | "conflicting", | |
dcb399de | 1012 | path->dentry, ovl_xino_mode(&ofs->config)); |
7e63c87f | 1013 | } |
9df085f3 AG |
1014 | } |
1015 | ||
5148626b AG |
1016 | err = get_anon_bdev(&dev); |
1017 | if (err) { | |
1bd0a3ae | 1018 | pr_err("failed to get anonymous bdev for lowerpath\n"); |
5148626b AG |
1019 | return err; |
1020 | } | |
1021 | ||
07f1e596 AG |
1022 | ofs->fs[ofs->numfs].sb = sb; |
1023 | ofs->fs[ofs->numfs].pseudo_dev = dev; | |
1024 | ofs->fs[ofs->numfs].bad_uuid = bad_uuid; | |
5148626b | 1025 | |
07f1e596 | 1026 | return ofs->numfs++; |
5148626b AG |
1027 | } |
1028 | ||
37ebf056 AG |
1029 | /* |
1030 | * The fsid after the last lower fsid is used for the data layers. | |
1031 | * It is a "null fs" with a null sb, null uuid, and no pseudo dev. | |
1032 | */ | |
1033 | static int ovl_get_data_fsid(struct ovl_fs *ofs) | |
1034 | { | |
1035 | return ofs->numfs; | |
1036 | } | |
1037 | ||
1038 | ||
94375f9d | 1039 | static int ovl_get_layers(struct super_block *sb, struct ovl_fs *ofs, |
b36a5780 | 1040 | struct ovl_fs_context *ctx, struct ovl_layer *layers) |
520d7c86 MS |
1041 | { |
1042 | int err; | |
1043 | unsigned int i; | |
b36a5780 | 1044 | size_t nr_merged_lower; |
520d7c86 | 1045 | |
b36a5780 | 1046 | ofs->fs = kcalloc(ctx->nr + 2, sizeof(struct ovl_sb), GFP_KERNEL); |
07f1e596 | 1047 | if (ofs->fs == NULL) |
9e88f905 | 1048 | return -ENOMEM; |
5148626b | 1049 | |
37ebf056 AG |
1050 | /* |
1051 | * idx/fsid 0 are reserved for upper fs even with lower only overlay | |
1052 | * and the last fsid is reserved for "null fs" of the data layers. | |
1053 | */ | |
07f1e596 AG |
1054 | ofs->numfs++; |
1055 | ||
07f1e596 | 1056 | /* |
b7bf9908 AG |
1057 | * All lower layers that share the same fs as upper layer, use the same |
1058 | * pseudo_dev as upper layer. Allocate fs[0].pseudo_dev even for lower | |
1059 | * only overlay to simplify ovl_fs_free(). | |
1b81dddd | 1060 | * is_lower will be set if upper fs is shared with a lower layer. |
07f1e596 | 1061 | */ |
b7bf9908 AG |
1062 | err = get_anon_bdev(&ofs->fs[0].pseudo_dev); |
1063 | if (err) { | |
1064 | pr_err("failed to get anonymous bdev for upper fs\n"); | |
9e88f905 | 1065 | return err; |
b7bf9908 AG |
1066 | } |
1067 | ||
08f4c7c8 MS |
1068 | if (ovl_upper_mnt(ofs)) { |
1069 | ofs->fs[0].sb = ovl_upper_mnt(ofs)->mnt_sb; | |
1b81dddd | 1070 | ofs->fs[0].is_lower = false; |
07f1e596 AG |
1071 | } |
1072 | ||
b36a5780 CB |
1073 | nr_merged_lower = ctx->nr - ctx->nr_data; |
1074 | for (i = 0; i < ctx->nr; i++) { | |
1075 | struct ovl_fs_context_layer *l = &ctx->lower[i]; | |
520d7c86 | 1076 | struct vfsmount *mnt; |
146d62e5 | 1077 | struct inode *trap; |
5148626b | 1078 | int fsid; |
520d7c86 | 1079 | |
b36a5780 CB |
1080 | if (i < nr_merged_lower) |
1081 | fsid = ovl_get_fsid(ofs, &l->path); | |
37ebf056 AG |
1082 | else |
1083 | fsid = ovl_get_data_fsid(ofs); | |
9e88f905 AG |
1084 | if (fsid < 0) |
1085 | return fsid; | |
520d7c86 | 1086 | |
24f14009 | 1087 | /* |
1088 | * Check if lower root conflicts with this overlay layers before | |
1089 | * checking if it is in-use as upperdir/workdir of "another" | |
1090 | * mount, because we do not bother to check in ovl_is_inuse() if | |
1091 | * the upperdir/workdir is in fact in-use by our | |
1092 | * upperdir/workdir. | |
1093 | */ | |
b36a5780 | 1094 | err = ovl_setup_trap(sb, l->path.dentry, &trap, "lowerdir"); |
146d62e5 | 1095 | if (err) |
9e88f905 | 1096 | return err; |
146d62e5 | 1097 | |
b36a5780 | 1098 | if (ovl_is_inuse(l->path.dentry)) { |
0be0bfd2 | 1099 | err = ovl_report_in_use(ofs, "lowerdir"); |
24f14009 | 1100 | if (err) { |
1101 | iput(trap); | |
9e88f905 | 1102 | return err; |
24f14009 | 1103 | } |
0be0bfd2 AG |
1104 | } |
1105 | ||
b36a5780 | 1106 | mnt = clone_private_mount(&l->path); |
520d7c86 MS |
1107 | err = PTR_ERR(mnt); |
1108 | if (IS_ERR(mnt)) { | |
1bd0a3ae | 1109 | pr_err("failed to clone lowerpath\n"); |
146d62e5 | 1110 | iput(trap); |
9e88f905 | 1111 | return err; |
520d7c86 | 1112 | } |
5148626b | 1113 | |
520d7c86 MS |
1114 | /* |
1115 | * Make lower layers R/O. That way fchmod/fchown on lower file | |
1116 | * will fail instead of modifying lower fs. | |
1117 | */ | |
1118 | mnt->mnt_flags |= MNT_READONLY | MNT_NOATIME; | |
1119 | ||
13464165 MS |
1120 | layers[ofs->numlayer].trap = trap; |
1121 | layers[ofs->numlayer].mnt = mnt; | |
1122 | layers[ofs->numlayer].idx = ofs->numlayer; | |
1123 | layers[ofs->numlayer].fsid = fsid; | |
1124 | layers[ofs->numlayer].fs = &ofs->fs[fsid]; | |
b36a5780 CB |
1125 | layers[ofs->numlayer].name = l->name; |
1126 | l->name = NULL; | |
94375f9d | 1127 | ofs->numlayer++; |
1b81dddd | 1128 | ofs->fs[fsid].is_lower = true; |
520d7c86 | 1129 | } |
e487d889 | 1130 | |
795939a9 AG |
1131 | /* |
1132 | * When all layers on same fs, overlay can use real inode numbers. | |
926e94d7 AG |
1133 | * With mount option "xino=<on|auto>", mounter declares that there are |
1134 | * enough free high bits in underlying fs to hold the unique fsid. | |
795939a9 AG |
1135 | * If overlayfs does encounter underlying inodes using the high xino |
1136 | * bits reserved for fsid, it emits a warning and uses the original | |
dfe51d47 AG |
1137 | * inode number or a non persistent inode number allocated from a |
1138 | * dedicated range. | |
795939a9 | 1139 | */ |
08f4c7c8 | 1140 | if (ofs->numfs - !ovl_upper_mnt(ofs) == 1) { |
0f831ec8 AG |
1141 | if (ofs->config.xino == OVL_XINO_ON) |
1142 | pr_info("\"xino=on\" is useless with all layers on same fs, ignore.\n"); | |
1143 | ofs->xino_mode = 0; | |
53afcd31 AG |
1144 | } else if (ofs->config.xino == OVL_XINO_OFF) { |
1145 | ofs->xino_mode = -1; | |
926e94d7 | 1146 | } else if (ofs->xino_mode < 0) { |
795939a9 | 1147 | /* |
07f1e596 | 1148 | * This is a roundup of number of bits needed for encoding |
dfe51d47 AG |
1149 | * fsid, where fsid 0 is reserved for upper fs (even with |
1150 | * lower only overlay) +1 extra bit is reserved for the non | |
1151 | * persistent inode number range that is used for resolving | |
1152 | * xino lower bits overflow. | |
795939a9 | 1153 | */ |
dfe51d47 AG |
1154 | BUILD_BUG_ON(ilog2(OVL_MAX_STACK) > 30); |
1155 | ofs->xino_mode = ilog2(ofs->numfs - 1) + 2; | |
795939a9 AG |
1156 | } |
1157 | ||
0f831ec8 | 1158 | if (ofs->xino_mode > 0) { |
1bd0a3ae | 1159 | pr_info("\"xino\" feature enabled using %d upper inode bits.\n", |
0f831ec8 | 1160 | ofs->xino_mode); |
795939a9 | 1161 | } |
e487d889 | 1162 | |
9e88f905 | 1163 | return 0; |
520d7c86 MS |
1164 | } |
1165 | ||
4155c10a | 1166 | static struct ovl_entry *ovl_get_lowerstack(struct super_block *sb, |
b36a5780 CB |
1167 | struct ovl_fs_context *ctx, |
1168 | struct ovl_fs *ofs, | |
1169 | struct ovl_layer *layers) | |
53dbb0b4 MS |
1170 | { |
1171 | int err; | |
b8e42a65 | 1172 | unsigned int i; |
b36a5780 | 1173 | size_t nr_merged_lower; |
4155c10a | 1174 | struct ovl_entry *oe; |
b36a5780 CB |
1175 | struct ovl_path *lowerstack; |
1176 | ||
1177 | struct ovl_fs_context_layer *l; | |
53dbb0b4 | 1178 | |
b36a5780 | 1179 | if (!ofs->config.upperdir && ctx->nr == 1) { |
1bd0a3ae | 1180 | pr_err("at least 2 lowerdir are needed while upperdir nonexistent\n"); |
b8e42a65 | 1181 | return ERR_PTR(-EINVAL); |
53dbb0b4 MS |
1182 | } |
1183 | ||
b36a5780 CB |
1184 | err = -EINVAL; |
1185 | for (i = 0; i < ctx->nr; i++) { | |
1186 | l = &ctx->lower[i]; | |
53dbb0b4 | 1187 | |
b36a5780 | 1188 | err = ovl_lower_dir(l->name, &l->path, ofs, &sb->s_stack_depth); |
53dbb0b4 | 1189 | if (err) |
b36a5780 | 1190 | return ERR_PTR(err); |
53dbb0b4 MS |
1191 | } |
1192 | ||
1193 | err = -EINVAL; | |
1194 | sb->s_stack_depth++; | |
1195 | if (sb->s_stack_depth > FILESYSTEM_MAX_STACK_DEPTH) { | |
1bd0a3ae | 1196 | pr_err("maximum fs stacking depth exceeded\n"); |
b36a5780 | 1197 | return ERR_PTR(err); |
53dbb0b4 MS |
1198 | } |
1199 | ||
b36a5780 | 1200 | err = ovl_get_layers(sb, ofs, ctx, layers); |
4155c10a | 1201 | if (err) |
b36a5780 | 1202 | return ERR_PTR(err); |
4155c10a MS |
1203 | |
1204 | err = -ENOMEM; | |
37ebf056 | 1205 | /* Data-only layers are not merged in root directory */ |
b36a5780 CB |
1206 | nr_merged_lower = ctx->nr - ctx->nr_data; |
1207 | oe = ovl_alloc_entry(nr_merged_lower); | |
4155c10a | 1208 | if (!oe) |
b36a5780 | 1209 | return ERR_PTR(err); |
4155c10a | 1210 | |
5522c9c7 | 1211 | lowerstack = ovl_lowerstack(oe); |
b36a5780 CB |
1212 | for (i = 0; i < nr_merged_lower; i++) { |
1213 | l = &ctx->lower[i]; | |
1214 | lowerstack[i].dentry = dget(l->path.dentry); | |
1215 | lowerstack[i].layer = &ofs->layers[i + 1]; | |
4155c10a | 1216 | } |
b36a5780 | 1217 | ofs->numdatalayer = ctx->nr_data; |
4155c10a MS |
1218 | |
1219 | return oe; | |
53dbb0b4 MS |
1220 | } |
1221 | ||
146d62e5 AG |
1222 | /* |
1223 | * Check if this layer root is a descendant of: | |
1224 | * - another layer of this overlayfs instance | |
1225 | * - upper/work dir of any overlayfs instance | |
146d62e5 | 1226 | */ |
0be0bfd2 | 1227 | static int ovl_check_layer(struct super_block *sb, struct ovl_fs *ofs, |
708fa015 MS |
1228 | struct dentry *dentry, const char *name, |
1229 | bool is_lower) | |
146d62e5 | 1230 | { |
9179c21d | 1231 | struct dentry *next = dentry, *parent; |
146d62e5 AG |
1232 | int err = 0; |
1233 | ||
9179c21d | 1234 | if (!dentry) |
146d62e5 AG |
1235 | return 0; |
1236 | ||
9179c21d MS |
1237 | parent = dget_parent(next); |
1238 | ||
1239 | /* Walk back ancestors to root (inclusive) looking for traps */ | |
1240 | while (!err && parent != next) { | |
708fa015 | 1241 | if (is_lower && ovl_lookup_trap_inode(sb, parent)) { |
146d62e5 | 1242 | err = -ELOOP; |
1bd0a3ae | 1243 | pr_err("overlapping %s path\n", name); |
0be0bfd2 AG |
1244 | } else if (ovl_is_inuse(parent)) { |
1245 | err = ovl_report_in_use(ofs, name); | |
146d62e5 | 1246 | } |
146d62e5 | 1247 | next = parent; |
9179c21d MS |
1248 | parent = dget_parent(next); |
1249 | dput(next); | |
146d62e5 AG |
1250 | } |
1251 | ||
9179c21d | 1252 | dput(parent); |
146d62e5 AG |
1253 | |
1254 | return err; | |
1255 | } | |
1256 | ||
1257 | /* | |
1258 | * Check if any of the layers or work dirs overlap. | |
1259 | */ | |
1260 | static int ovl_check_overlapping_layers(struct super_block *sb, | |
1261 | struct ovl_fs *ofs) | |
1262 | { | |
1263 | int i, err; | |
1264 | ||
08f4c7c8 MS |
1265 | if (ovl_upper_mnt(ofs)) { |
1266 | err = ovl_check_layer(sb, ofs, ovl_upper_mnt(ofs)->mnt_root, | |
708fa015 | 1267 | "upperdir", false); |
146d62e5 AG |
1268 | if (err) |
1269 | return err; | |
1270 | ||
1271 | /* | |
1272 | * Checking workbasedir avoids hitting ovl_is_inuse(parent) of | |
1273 | * this instance and covers overlapping work and index dirs, | |
1274 | * unless work or index dir have been moved since created inside | |
1275 | * workbasedir. In that case, we already have their traps in | |
1276 | * inode cache and we will catch that case on lookup. | |
1277 | */ | |
708fa015 MS |
1278 | err = ovl_check_layer(sb, ofs, ofs->workbasedir, "workdir", |
1279 | false); | |
146d62e5 AG |
1280 | if (err) |
1281 | return err; | |
1282 | } | |
1283 | ||
94375f9d | 1284 | for (i = 1; i < ofs->numlayer; i++) { |
0be0bfd2 | 1285 | err = ovl_check_layer(sb, ofs, |
94375f9d | 1286 | ofs->layers[i].mnt->mnt_root, |
708fa015 | 1287 | "lowerdir", true); |
146d62e5 AG |
1288 | if (err) |
1289 | return err; | |
1290 | } | |
1291 | ||
1292 | return 0; | |
1293 | } | |
1294 | ||
2effc5c2 AG |
1295 | static struct dentry *ovl_get_root(struct super_block *sb, |
1296 | struct dentry *upperdentry, | |
1297 | struct ovl_entry *oe) | |
1298 | { | |
1299 | struct dentry *root; | |
5522c9c7 | 1300 | struct ovl_path *lowerpath = ovl_lowerstack(oe); |
62c832ed AG |
1301 | unsigned long ino = d_inode(lowerpath->dentry)->i_ino; |
1302 | int fsid = lowerpath->layer->fsid; | |
1303 | struct ovl_inode_params oip = { | |
1304 | .upperdentry = upperdentry, | |
0af950f5 | 1305 | .oe = oe, |
62c832ed | 1306 | }; |
2effc5c2 AG |
1307 | |
1308 | root = d_make_root(ovl_new_inode(sb, S_IFDIR, 0)); | |
1309 | if (!root) | |
1310 | return NULL; | |
1311 | ||
2effc5c2 | 1312 | if (upperdentry) { |
62c832ed AG |
1313 | /* Root inode uses upper st_ino/i_ino */ |
1314 | ino = d_inode(upperdentry)->i_ino; | |
1315 | fsid = 0; | |
2effc5c2 | 1316 | ovl_dentry_set_upper_alias(root); |
610afc0b | 1317 | if (ovl_is_impuredir(sb, upperdentry)) |
2effc5c2 AG |
1318 | ovl_set_flag(OVL_IMPURE, d_inode(root)); |
1319 | } | |
1320 | ||
1321 | /* Root is always merge -> can have whiteouts */ | |
1322 | ovl_set_flag(OVL_WHITEOUTS, d_inode(root)); | |
1323 | ovl_dentry_set_flag(OVL_E_CONNECTED, root); | |
1324 | ovl_set_upperdata(d_inode(root)); | |
62c832ed | 1325 | ovl_inode_init(d_inode(root), &oip, ino, fsid); |
0af950f5 | 1326 | ovl_dentry_init_flags(root, upperdentry, oe, DCACHE_OP_WEAK_REVALIDATE); |
367d002d AG |
1327 | /* root keeps a reference of upperdentry */ |
1328 | dget(upperdentry); | |
2effc5c2 AG |
1329 | |
1330 | return root; | |
1331 | } | |
1332 | ||
7fb7998b | 1333 | int ovl_fill_super(struct super_block *sb, struct fs_context *fc) |
e9be9d5e | 1334 | { |
1784fbc2 CB |
1335 | struct ovl_fs *ofs = sb->s_fs_info; |
1336 | struct ovl_fs_context *ctx = fc->fs_private; | |
e9be9d5e | 1337 | struct dentry *root_dentry; |
4155c10a | 1338 | struct ovl_entry *oe; |
b8e42a65 | 1339 | struct ovl_layer *layers; |
51f8f3c4 | 1340 | struct cred *cred; |
e9be9d5e MS |
1341 | int err; |
1342 | ||
9efb069d | 1343 | err = -EIO; |
1784fbc2 CB |
1344 | if (WARN_ON(fc->user_ns != current_user_ns())) |
1345 | goto out_err; | |
9efb069d | 1346 | |
f4288844 MS |
1347 | sb->s_d_op = &ovl_dentry_operations; |
1348 | ||
d7b49b10 | 1349 | err = -ENOMEM; |
ad204488 | 1350 | ofs->creator_cred = cred = prepare_creds(); |
c6fe6254 MS |
1351 | if (!cred) |
1352 | goto out_err; | |
1353 | ||
1784fbc2 | 1354 | err = ovl_fs_params_verify(ctx, &ofs->config); |
f45827e8 | 1355 | if (err) |
a9075cdb | 1356 | goto out_err; |
f45827e8 | 1357 | |
e9be9d5e | 1358 | err = -EINVAL; |
b36a5780 | 1359 | if (ctx->nr == 0) { |
1784fbc2 | 1360 | if (!(fc->sb_flags & SB_SILENT)) |
1bd0a3ae | 1361 | pr_err("missing 'lowerdir'\n"); |
a9075cdb | 1362 | goto out_err; |
e9be9d5e MS |
1363 | } |
1364 | ||
b8e42a65 | 1365 | err = -ENOMEM; |
b36a5780 | 1366 | layers = kcalloc(ctx->nr + 1, sizeof(struct ovl_layer), GFP_KERNEL); |
b8e42a65 MS |
1367 | if (!layers) |
1368 | goto out_err; | |
1369 | ||
1370 | ofs->layers = layers; | |
1371 | /* Layer 0 is reserved for upper even if there's no upper */ | |
1372 | ofs->numlayer = 1; | |
1373 | ||
53a08cb9 | 1374 | sb->s_stack_depth = 0; |
cf9a6784 | 1375 | sb->s_maxbytes = MAX_LFS_FILESIZE; |
4d314f78 | 1376 | atomic_long_set(&ofs->last_ino, 1); |
4f119628 | 1377 | /* Assume underlying fs uses 32bit inodes unless proven otherwise */ |
53afcd31 | 1378 | if (ofs->config.xino != OVL_XINO_OFF) { |
0f831ec8 | 1379 | ofs->xino_mode = BITS_PER_LONG - 32; |
53afcd31 AG |
1380 | if (!ofs->xino_mode) { |
1381 | pr_warn("xino not supported on 32bit kernel, falling back to xino=off.\n"); | |
1382 | ofs->config.xino = OVL_XINO_OFF; | |
1383 | } | |
1384 | } | |
795939a9 | 1385 | |
146d62e5 AG |
1386 | /* alloc/destroy_inode needed for setting up traps in inode cache */ |
1387 | sb->s_op = &ovl_super_operations; | |
1388 | ||
ad204488 | 1389 | if (ofs->config.upperdir) { |
335d3fc5 SD |
1390 | struct super_block *upper_sb; |
1391 | ||
d7b49b10 | 1392 | err = -EINVAL; |
ad204488 | 1393 | if (!ofs->config.workdir) { |
1bd0a3ae | 1394 | pr_err("missing 'workdir'\n"); |
a9075cdb | 1395 | goto out_err; |
53a08cb9 | 1396 | } |
e9be9d5e | 1397 | |
b36a5780 | 1398 | err = ovl_get_upper(sb, ofs, &layers[0], &ctx->upper); |
53a08cb9 | 1399 | if (err) |
a9075cdb | 1400 | goto out_err; |
2cac0c00 | 1401 | |
335d3fc5 SD |
1402 | upper_sb = ovl_upper_mnt(ofs)->mnt_sb; |
1403 | if (!ovl_should_sync(ofs)) { | |
1404 | ofs->errseq = errseq_sample(&upper_sb->s_wb_err); | |
1405 | if (errseq_check(&upper_sb->s_wb_err, ofs->errseq)) { | |
1406 | err = -EIO; | |
1407 | pr_err("Cannot mount volatile when upperdir has an unseen error. Sync upperdir fs to clear state.\n"); | |
1408 | goto out_err; | |
1409 | } | |
1410 | } | |
1411 | ||
b36a5780 | 1412 | err = ovl_get_workdir(sb, ofs, &ctx->upper, &ctx->work); |
8ed61dc3 | 1413 | if (err) |
a9075cdb | 1414 | goto out_err; |
c6fe6254 | 1415 | |
ad204488 | 1416 | if (!ofs->workdir) |
1751e8a6 | 1417 | sb->s_flags |= SB_RDONLY; |
6e88256e | 1418 | |
335d3fc5 SD |
1419 | sb->s_stack_depth = upper_sb->s_stack_depth; |
1420 | sb->s_time_gran = upper_sb->s_time_gran; | |
e9be9d5e | 1421 | } |
b36a5780 | 1422 | oe = ovl_get_lowerstack(sb, ctx, ofs, layers); |
4155c10a MS |
1423 | err = PTR_ERR(oe); |
1424 | if (IS_ERR(oe)) | |
a9075cdb | 1425 | goto out_err; |
e9be9d5e | 1426 | |
71cbad7e | 1427 | /* If the upper fs is nonexistent, we mark overlayfs r/o too */ |
08f4c7c8 | 1428 | if (!ovl_upper_mnt(ofs)) |
1751e8a6 | 1429 | sb->s_flags |= SB_RDONLY; |
e9be9d5e | 1430 | |
b0504bfe AG |
1431 | if (!ovl_origin_uuid(ofs) && ofs->numfs > 1) { |
1432 | pr_warn("The uuid=off requires a single fs for lower and upper, falling back to uuid=null.\n"); | |
1433 | ofs->config.uuid = OVL_UUID_NULL; | |
d9544c1b AG |
1434 | } else if (ovl_has_fsid(ofs) && ovl_upper_mnt(ofs)) { |
1435 | /* Use per instance persistent uuid/fsid */ | |
1436 | ovl_init_uuid_xattr(sb, ofs, &ctx->upper); | |
5830fb6b PT |
1437 | } |
1438 | ||
470c1563 | 1439 | if (!ovl_force_readonly(ofs) && ofs->config.index) { |
b36a5780 | 1440 | err = ovl_get_indexdir(sb, ofs, oe, &ctx->upper); |
54fb347e | 1441 | if (err) |
4155c10a | 1442 | goto out_free_oe; |
6e88256e | 1443 | |
972d0093 | 1444 | /* Force r/o mount with no index dir */ |
20396365 | 1445 | if (!ofs->indexdir) |
1751e8a6 | 1446 | sb->s_flags |= SB_RDONLY; |
02bcd157 AG |
1447 | } |
1448 | ||
146d62e5 AG |
1449 | err = ovl_check_overlapping_layers(sb, ofs); |
1450 | if (err) | |
1451 | goto out_free_oe; | |
1452 | ||
972d0093 | 1453 | /* Show index=off in /proc/mounts for forced r/o mount */ |
f168f109 | 1454 | if (!ofs->indexdir) { |
ad204488 | 1455 | ofs->config.index = false; |
08f4c7c8 | 1456 | if (ovl_upper_mnt(ofs) && ofs->config.nfs_export) { |
1bd0a3ae | 1457 | pr_warn("NFS export requires an index dir, falling back to nfs_export=off.\n"); |
f168f109 AG |
1458 | ofs->config.nfs_export = false; |
1459 | } | |
1460 | } | |
02bcd157 | 1461 | |
d5791044 | 1462 | if (ofs->config.metacopy && ofs->config.nfs_export) { |
1bd0a3ae | 1463 | pr_warn("NFS export is not supported with metadata only copy up, falling back to nfs_export=off.\n"); |
d5791044 VG |
1464 | ofs->config.nfs_export = false; |
1465 | } | |
1466 | ||
16aac5ad AG |
1467 | /* |
1468 | * Support encoding decodable file handles with nfs_export=on | |
1469 | * and encoding non-decodable file handles with nfs_export=off | |
1470 | * if all layers support file handles. | |
1471 | */ | |
8383f174 AG |
1472 | if (ofs->config.nfs_export) |
1473 | sb->s_export_op = &ovl_export_operations; | |
16aac5ad AG |
1474 | else if (!ofs->nofh) |
1475 | sb->s_export_op = &ovl_export_fid_operations; | |
8383f174 | 1476 | |
51f8f3c4 KK |
1477 | /* Never override disk quota limits or use reserved space */ |
1478 | cap_lower(cred->cap_effective, CAP_SYS_RESOURCE); | |
1479 | ||
655042cc | 1480 | sb->s_magic = OVERLAYFS_SUPER_MAGIC; |
2d2f2d73 MS |
1481 | sb->s_xattr = ofs->config.userxattr ? ovl_user_xattr_handlers : |
1482 | ovl_trusted_xattr_handlers; | |
ad204488 | 1483 | sb->s_fs_info = ofs; |
7c4d37c2 | 1484 | sb->s_flags |= SB_POSIXACL; |
18b44bc5 | 1485 | sb->s_iflags |= SB_I_SKIP_SYNC | SB_I_IMA_UNVERIFIABLE_SIGNATURE; |
655042cc | 1486 | |
c6fe6254 | 1487 | err = -ENOMEM; |
b36a5780 | 1488 | root_dentry = ovl_get_root(sb, ctx->upper.dentry, oe); |
e9be9d5e | 1489 | if (!root_dentry) |
4155c10a | 1490 | goto out_free_oe; |
e9be9d5e | 1491 | |
e9be9d5e | 1492 | sb->s_root = root_dentry; |
e9be9d5e MS |
1493 | |
1494 | return 0; | |
1495 | ||
4155c10a | 1496 | out_free_oe: |
163db0da | 1497 | ovl_free_entry(oe); |
4155c10a | 1498 | out_err: |
ad204488 | 1499 | ovl_free_fs(ofs); |
1784fbc2 | 1500 | sb->s_fs_info = NULL; |
e9be9d5e MS |
1501 | return err; |
1502 | } | |
1503 | ||
f01d0889 | 1504 | struct file_system_type ovl_fs_type = { |
1784fbc2 CB |
1505 | .owner = THIS_MODULE, |
1506 | .name = "overlay", | |
1507 | .init_fs_context = ovl_init_fs_context, | |
1508 | .parameters = ovl_parameter_spec, | |
1509 | .fs_flags = FS_USERNS_MOUNT, | |
1510 | .kill_sb = kill_anon_super, | |
e9be9d5e | 1511 | }; |
ef94b186 | 1512 | MODULE_ALIAS_FS("overlay"); |
e9be9d5e | 1513 | |
13cf199d AG |
1514 | static void ovl_inode_init_once(void *foo) |
1515 | { | |
1516 | struct ovl_inode *oi = foo; | |
1517 | ||
1518 | inode_init_once(&oi->vfs_inode); | |
1519 | } | |
1520 | ||
e9be9d5e MS |
1521 | static int __init ovl_init(void) |
1522 | { | |
13cf199d AG |
1523 | int err; |
1524 | ||
1525 | ovl_inode_cachep = kmem_cache_create("ovl_inode", | |
1526 | sizeof(struct ovl_inode), 0, | |
1527 | (SLAB_RECLAIM_ACCOUNT| | |
1528 | SLAB_MEM_SPREAD|SLAB_ACCOUNT), | |
1529 | ovl_inode_init_once); | |
1530 | if (ovl_inode_cachep == NULL) | |
1531 | return -ENOMEM; | |
1532 | ||
2406a307 JX |
1533 | err = ovl_aio_request_cache_init(); |
1534 | if (!err) { | |
1535 | err = register_filesystem(&ovl_fs_type); | |
1536 | if (!err) | |
1537 | return 0; | |
1538 | ||
1539 | ovl_aio_request_cache_destroy(); | |
1540 | } | |
1541 | kmem_cache_destroy(ovl_inode_cachep); | |
13cf199d AG |
1542 | |
1543 | return err; | |
e9be9d5e MS |
1544 | } |
1545 | ||
1546 | static void __exit ovl_exit(void) | |
1547 | { | |
1548 | unregister_filesystem(&ovl_fs_type); | |
13cf199d AG |
1549 | |
1550 | /* | |
1551 | * Make sure all delayed rcu free inodes are flushed before we | |
1552 | * destroy cache. | |
1553 | */ | |
1554 | rcu_barrier(); | |
1555 | kmem_cache_destroy(ovl_inode_cachep); | |
2406a307 | 1556 | ovl_aio_request_cache_destroy(); |
e9be9d5e MS |
1557 | } |
1558 | ||
1559 | module_init(ovl_init); | |
1560 | module_exit(ovl_exit); |