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Commit | Line | Data |
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1da177e4 | 1 | /* |
f1adc05e | 2 | * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com) |
1da177e4 LT |
3 | * Licensed under the GPL |
4 | * | |
5 | * Ported the filesystem routines to 2.5. | |
6 | * 2003-02-10 Petr Baudis <pasky@ucw.cz> | |
7 | */ | |
8 | ||
1da177e4 | 9 | #include <linux/fs.h> |
2b3b9bb0 | 10 | #include <linux/magic.h> |
1da177e4 | 11 | #include <linux/module.h> |
84b3db04 | 12 | #include <linux/mm.h> |
1da177e4 | 13 | #include <linux/pagemap.h> |
1da177e4 | 14 | #include <linux/statfs.h> |
5a0e3ad6 | 15 | #include <linux/slab.h> |
dd2cc4df | 16 | #include <linux/seq_file.h> |
6966a977 | 17 | #include <linux/mount.h> |
d0352d3e | 18 | #include <linux/namei.h> |
1da177e4 | 19 | #include "hostfs.h" |
37185b33 AV |
20 | #include <init.h> |
21 | #include <kern.h> | |
1da177e4 LT |
22 | |
23 | struct hostfs_inode_info { | |
1da177e4 | 24 | int fd; |
aeb5d727 | 25 | fmode_t mode; |
1da177e4 | 26 | struct inode vfs_inode; |
69886e67 | 27 | struct mutex open_mutex; |
1da177e4 LT |
28 | }; |
29 | ||
30 | static inline struct hostfs_inode_info *HOSTFS_I(struct inode *inode) | |
31 | { | |
f1adc05e | 32 | return list_entry(inode, struct hostfs_inode_info, vfs_inode); |
1da177e4 LT |
33 | } |
34 | ||
496ad9aa | 35 | #define FILE_HOSTFS_I(file) HOSTFS_I(file_inode(file)) |
1da177e4 | 36 | |
1da177e4 | 37 | /* Changed in hostfs_args before the kernel starts running */ |
a6eb0be6 | 38 | static char *root_ino = ""; |
1da177e4 LT |
39 | static int append = 0; |
40 | ||
92e1d5be AV |
41 | static const struct inode_operations hostfs_iops; |
42 | static const struct inode_operations hostfs_dir_iops; | |
d0352d3e | 43 | static const struct inode_operations hostfs_link_iops; |
1da177e4 LT |
44 | |
45 | #ifndef MODULE | |
46 | static int __init hostfs_args(char *options, int *add) | |
47 | { | |
48 | char *ptr; | |
49 | ||
50 | ptr = strchr(options, ','); | |
84b3db04 | 51 | if (ptr != NULL) |
1da177e4 | 52 | *ptr++ = '\0'; |
84b3db04 | 53 | if (*options != '\0') |
1da177e4 LT |
54 | root_ino = options; |
55 | ||
56 | options = ptr; | |
84b3db04 | 57 | while (options) { |
1da177e4 | 58 | ptr = strchr(options, ','); |
84b3db04 | 59 | if (ptr != NULL) |
1da177e4 | 60 | *ptr++ = '\0'; |
84b3db04 JD |
61 | if (*options != '\0') { |
62 | if (!strcmp(options, "append")) | |
1da177e4 LT |
63 | append = 1; |
64 | else printf("hostfs_args - unsupported option - %s\n", | |
65 | options); | |
66 | } | |
67 | options = ptr; | |
68 | } | |
f1adc05e | 69 | return 0; |
1da177e4 LT |
70 | } |
71 | ||
72 | __uml_setup("hostfs=", hostfs_args, | |
73 | "hostfs=<root dir>,<flags>,...\n" | |
74 | " This is used to set hostfs parameters. The root directory argument\n" | |
75 | " is used to confine all hostfs mounts to within the specified directory\n" | |
76 | " tree on the host. If this isn't specified, then a user inside UML can\n" | |
77 | " mount anything on the host that's accessible to the user that's running\n" | |
78 | " it.\n" | |
79 | " The only flag currently supported is 'append', which specifies that all\n" | |
80 | " files opened by hostfs will be opened in append mode.\n\n" | |
81 | ); | |
82 | #endif | |
83 | ||
e9193059 | 84 | static char *__dentry_name(struct dentry *dentry, char *name) |
1da177e4 | 85 | { |
ec2447c2 | 86 | char *p = dentry_path_raw(dentry, name, PATH_MAX); |
e9193059 AV |
87 | char *root; |
88 | size_t len; | |
1da177e4 | 89 | |
e9193059 AV |
90 | root = dentry->d_sb->s_fs_info; |
91 | len = strlen(root); | |
92 | if (IS_ERR(p)) { | |
93 | __putname(name); | |
f1adc05e | 94 | return NULL; |
1da177e4 | 95 | } |
aad50b1e RW |
96 | |
97 | /* | |
98 | * This function relies on the fact that dentry_path_raw() will place | |
99 | * the path name at the end of the provided buffer. | |
100 | */ | |
101 | BUG_ON(p + strlen(p) + 1 != name + PATH_MAX); | |
102 | ||
850a496f | 103 | strlcpy(name, root, PATH_MAX); |
e9193059 AV |
104 | if (len > p - name) { |
105 | __putname(name); | |
106 | return NULL; | |
107 | } | |
c278e81b RW |
108 | |
109 | if (p > name + len) | |
110 | strcpy(name + len, p); | |
111 | ||
f1adc05e | 112 | return name; |
1da177e4 LT |
113 | } |
114 | ||
e9193059 AV |
115 | static char *dentry_name(struct dentry *dentry) |
116 | { | |
117 | char *name = __getname(); | |
118 | if (!name) | |
119 | return NULL; | |
120 | ||
9dcc5e8a | 121 | return __dentry_name(dentry, name); |
e9193059 AV |
122 | } |
123 | ||
c5322220 | 124 | static char *inode_name(struct inode *ino) |
1da177e4 LT |
125 | { |
126 | struct dentry *dentry; | |
ec2447c2 | 127 | char *name; |
1da177e4 | 128 | |
ec2447c2 NP |
129 | dentry = d_find_alias(ino); |
130 | if (!dentry) | |
e9193059 | 131 | return NULL; |
ec2447c2 NP |
132 | |
133 | name = dentry_name(dentry); | |
134 | ||
135 | dput(dentry); | |
136 | ||
137 | return name; | |
1da177e4 LT |
138 | } |
139 | ||
1da177e4 LT |
140 | static char *follow_link(char *link) |
141 | { | |
142 | int len, n; | |
143 | char *name, *resolved, *end; | |
144 | ||
7c950992 RW |
145 | name = __getname(); |
146 | if (!name) { | |
1da177e4 | 147 | n = -ENOMEM; |
7c950992 | 148 | goto out_free; |
1da177e4 | 149 | } |
7c950992 RW |
150 | |
151 | n = hostfs_do_readlink(link, name, PATH_MAX); | |
84b3db04 | 152 | if (n < 0) |
1da177e4 | 153 | goto out_free; |
7c950992 RW |
154 | else if (n == PATH_MAX) { |
155 | n = -E2BIG; | |
156 | goto out_free; | |
157 | } | |
1da177e4 | 158 | |
84b3db04 | 159 | if (*name == '/') |
f1adc05e | 160 | return name; |
1da177e4 LT |
161 | |
162 | end = strrchr(link, '/'); | |
84b3db04 | 163 | if (end == NULL) |
f1adc05e | 164 | return name; |
1da177e4 LT |
165 | |
166 | *(end + 1) = '\0'; | |
167 | len = strlen(link) + strlen(name) + 1; | |
168 | ||
169 | resolved = kmalloc(len, GFP_KERNEL); | |
84b3db04 | 170 | if (resolved == NULL) { |
1da177e4 LT |
171 | n = -ENOMEM; |
172 | goto out_free; | |
173 | } | |
174 | ||
175 | sprintf(resolved, "%s%s", link, name); | |
7c950992 | 176 | __putname(name); |
1da177e4 | 177 | kfree(link); |
f1adc05e | 178 | return resolved; |
1da177e4 LT |
179 | |
180 | out_free: | |
7c950992 | 181 | __putname(name); |
f1adc05e | 182 | return ERR_PTR(n); |
1da177e4 LT |
183 | } |
184 | ||
0a370e5d DH |
185 | static struct inode *hostfs_iget(struct super_block *sb) |
186 | { | |
52b209f7 | 187 | struct inode *inode = new_inode(sb); |
0a370e5d DH |
188 | if (!inode) |
189 | return ERR_PTR(-ENOMEM); | |
0a370e5d DH |
190 | return inode; |
191 | } | |
192 | ||
9e443bc3 | 193 | static int hostfs_statfs(struct dentry *dentry, struct kstatfs *sf) |
1da177e4 | 194 | { |
84b3db04 JD |
195 | /* |
196 | * do_statfs uses struct statfs64 internally, but the linux kernel | |
1da177e4 LT |
197 | * struct statfs still has 32-bit versions for most of these fields, |
198 | * so we convert them here | |
199 | */ | |
200 | int err; | |
201 | long long f_blocks; | |
202 | long long f_bfree; | |
203 | long long f_bavail; | |
204 | long long f_files; | |
205 | long long f_ffree; | |
206 | ||
601d2c38 | 207 | err = do_statfs(dentry->d_sb->s_fs_info, |
1da177e4 LT |
208 | &sf->f_bsize, &f_blocks, &f_bfree, &f_bavail, &f_files, |
209 | &f_ffree, &sf->f_fsid, sizeof(sf->f_fsid), | |
1b627d57 | 210 | &sf->f_namelen); |
84b3db04 | 211 | if (err) |
f1adc05e | 212 | return err; |
1da177e4 LT |
213 | sf->f_blocks = f_blocks; |
214 | sf->f_bfree = f_bfree; | |
215 | sf->f_bavail = f_bavail; | |
216 | sf->f_files = f_files; | |
217 | sf->f_ffree = f_ffree; | |
218 | sf->f_type = HOSTFS_SUPER_MAGIC; | |
f1adc05e | 219 | return 0; |
1da177e4 LT |
220 | } |
221 | ||
222 | static struct inode *hostfs_alloc_inode(struct super_block *sb) | |
223 | { | |
224 | struct hostfs_inode_info *hi; | |
225 | ||
5d097056 | 226 | hi = kmalloc(sizeof(*hi), GFP_KERNEL_ACCOUNT); |
84b3db04 | 227 | if (hi == NULL) |
f1adc05e | 228 | return NULL; |
601d2c38 | 229 | hi->fd = -1; |
371fdab1 | 230 | hi->mode = 0; |
1da177e4 | 231 | inode_init_once(&hi->vfs_inode); |
69886e67 | 232 | mutex_init(&hi->open_mutex); |
f1adc05e | 233 | return &hi->vfs_inode; |
1da177e4 LT |
234 | } |
235 | ||
e971a6d7 | 236 | static void hostfs_evict_inode(struct inode *inode) |
1da177e4 | 237 | { |
91b0abe3 | 238 | truncate_inode_pages_final(&inode->i_data); |
dbd5768f | 239 | clear_inode(inode); |
84b3db04 | 240 | if (HOSTFS_I(inode)->fd != -1) { |
1da177e4 LT |
241 | close_file(&HOSTFS_I(inode)->fd); |
242 | HOSTFS_I(inode)->fd = -1; | |
243 | } | |
1da177e4 LT |
244 | } |
245 | ||
08ccfc5c | 246 | static void hostfs_free_inode(struct inode *inode) |
1da177e4 | 247 | { |
1da177e4 LT |
248 | kfree(HOSTFS_I(inode)); |
249 | } | |
fa0d7e3d | 250 | |
34c80b1d | 251 | static int hostfs_show_options(struct seq_file *seq, struct dentry *root) |
dd2cc4df | 252 | { |
34c80b1d | 253 | const char *root_path = root->d_sb->s_fs_info; |
dd2cc4df MS |
254 | size_t offset = strlen(root_ino) + 1; |
255 | ||
256 | if (strlen(root_path) > offset) | |
a068acf2 | 257 | seq_show_option(seq, root_path + offset, NULL); |
dd2cc4df | 258 | |
7f74a668 RW |
259 | if (append) |
260 | seq_puts(seq, ",append"); | |
261 | ||
dd2cc4df MS |
262 | return 0; |
263 | } | |
264 | ||
ee9b6d61 | 265 | static const struct super_operations hostfs_sbops = { |
1da177e4 | 266 | .alloc_inode = hostfs_alloc_inode, |
08ccfc5c | 267 | .free_inode = hostfs_free_inode, |
e971a6d7 | 268 | .evict_inode = hostfs_evict_inode, |
1da177e4 | 269 | .statfs = hostfs_statfs, |
dd2cc4df | 270 | .show_options = hostfs_show_options, |
1da177e4 LT |
271 | }; |
272 | ||
9e443bc3 | 273 | static int hostfs_readdir(struct file *file, struct dir_context *ctx) |
1da177e4 LT |
274 | { |
275 | void *dir; | |
276 | char *name; | |
277 | unsigned long long next, ino; | |
278 | int error, len; | |
3ee6bd8e | 279 | unsigned int type; |
1da177e4 | 280 | |
c5322220 | 281 | name = dentry_name(file->f_path.dentry); |
84b3db04 | 282 | if (name == NULL) |
f1adc05e | 283 | return -ENOMEM; |
1da177e4 | 284 | dir = open_dir(name, &error); |
e9193059 | 285 | __putname(name); |
84b3db04 | 286 | if (dir == NULL) |
f1adc05e | 287 | return -error; |
8e28bc7e | 288 | next = ctx->pos; |
0c9bd636 | 289 | seek_dir(dir, next); |
3ee6bd8e | 290 | while ((name = read_dir(dir, &next, &ino, &len, &type)) != NULL) { |
8e28bc7e AV |
291 | if (!dir_emit(ctx, name, len, ino, type)) |
292 | break; | |
293 | ctx->pos = next; | |
1da177e4 LT |
294 | } |
295 | close_dir(dir); | |
f1adc05e | 296 | return 0; |
1da177e4 LT |
297 | } |
298 | ||
4c6dcafc | 299 | static int hostfs_open(struct inode *ino, struct file *file) |
1da177e4 LT |
300 | { |
301 | char *name; | |
bd1052a2 | 302 | fmode_t mode; |
f8ad850f | 303 | int err; |
bd1052a2 | 304 | int r, w, fd; |
1da177e4 LT |
305 | |
306 | mode = file->f_mode & (FMODE_READ | FMODE_WRITE); | |
84b3db04 | 307 | if ((mode & HOSTFS_I(ino)->mode) == mode) |
f1adc05e | 308 | return 0; |
1da177e4 | 309 | |
f8ad850f | 310 | mode |= HOSTFS_I(ino)->mode; |
1da177e4 | 311 | |
f8ad850f | 312 | retry: |
a9d1958b RW |
313 | r = w = 0; |
314 | ||
f8ad850f | 315 | if (mode & FMODE_READ) |
1da177e4 | 316 | r = 1; |
f8ad850f | 317 | if (mode & FMODE_WRITE) |
112a5da7 | 318 | r = w = 1; |
1da177e4 | 319 | |
c5322220 | 320 | name = dentry_name(file->f_path.dentry); |
84b3db04 | 321 | if (name == NULL) |
f1adc05e | 322 | return -ENOMEM; |
1da177e4 LT |
323 | |
324 | fd = open_file(name, r, w, append); | |
e9193059 | 325 | __putname(name); |
84b3db04 | 326 | if (fd < 0) |
f1adc05e | 327 | return fd; |
f8ad850f | 328 | |
69886e67 | 329 | mutex_lock(&HOSTFS_I(ino)->open_mutex); |
f8ad850f AV |
330 | /* somebody else had handled it first? */ |
331 | if ((mode & HOSTFS_I(ino)->mode) == mode) { | |
69886e67 | 332 | mutex_unlock(&HOSTFS_I(ino)->open_mutex); |
af955658 | 333 | close_file(&fd); |
f8ad850f AV |
334 | return 0; |
335 | } | |
336 | if ((mode | HOSTFS_I(ino)->mode) != mode) { | |
337 | mode |= HOSTFS_I(ino)->mode; | |
69886e67 | 338 | mutex_unlock(&HOSTFS_I(ino)->open_mutex); |
f8ad850f AV |
339 | close_file(&fd); |
340 | goto retry; | |
341 | } | |
342 | if (HOSTFS_I(ino)->fd == -1) { | |
343 | HOSTFS_I(ino)->fd = fd; | |
344 | } else { | |
345 | err = replace_file(fd, HOSTFS_I(ino)->fd); | |
346 | close_file(&fd); | |
347 | if (err < 0) { | |
69886e67 | 348 | mutex_unlock(&HOSTFS_I(ino)->open_mutex); |
f8ad850f AV |
349 | return err; |
350 | } | |
351 | } | |
352 | HOSTFS_I(ino)->mode = mode; | |
69886e67 | 353 | mutex_unlock(&HOSTFS_I(ino)->open_mutex); |
1da177e4 | 354 | |
f1adc05e | 355 | return 0; |
1da177e4 LT |
356 | } |
357 | ||
65984ff9 RW |
358 | static int hostfs_file_release(struct inode *inode, struct file *file) |
359 | { | |
360 | filemap_write_and_wait(inode->i_mapping); | |
361 | ||
362 | return 0; | |
363 | } | |
364 | ||
9e443bc3 JH |
365 | static int hostfs_fsync(struct file *file, loff_t start, loff_t end, |
366 | int datasync) | |
1da177e4 | 367 | { |
02c24a82 JB |
368 | struct inode *inode = file->f_mapping->host; |
369 | int ret; | |
370 | ||
3b49c9a1 | 371 | ret = file_write_and_wait_range(file, start, end); |
02c24a82 JB |
372 | if (ret) |
373 | return ret; | |
374 | ||
5955102c | 375 | inode_lock(inode); |
02c24a82 | 376 | ret = fsync_file(HOSTFS_I(inode)->fd, datasync); |
5955102c | 377 | inode_unlock(inode); |
02c24a82 JB |
378 | |
379 | return ret; | |
1da177e4 LT |
380 | } |
381 | ||
4b6f5d20 | 382 | static const struct file_operations hostfs_file_fops = { |
1da177e4 | 383 | .llseek = generic_file_llseek, |
5ffc4ef4 | 384 | .splice_read = generic_file_splice_read, |
aad4f8bb | 385 | .read_iter = generic_file_read_iter, |
8174202b | 386 | .write_iter = generic_file_write_iter, |
1da177e4 | 387 | .mmap = generic_file_mmap, |
4c6dcafc | 388 | .open = hostfs_open, |
65984ff9 | 389 | .release = hostfs_file_release, |
1da177e4 LT |
390 | .fsync = hostfs_fsync, |
391 | }; | |
392 | ||
4b6f5d20 | 393 | static const struct file_operations hostfs_dir_fops = { |
1da177e4 | 394 | .llseek = generic_file_llseek, |
552a9d48 | 395 | .iterate_shared = hostfs_readdir, |
1da177e4 | 396 | .read = generic_read_dir, |
4c6dcafc RW |
397 | .open = hostfs_open, |
398 | .fsync = hostfs_fsync, | |
1da177e4 LT |
399 | }; |
400 | ||
9e443bc3 | 401 | static int hostfs_writepage(struct page *page, struct writeback_control *wbc) |
1da177e4 LT |
402 | { |
403 | struct address_space *mapping = page->mapping; | |
404 | struct inode *inode = mapping->host; | |
405 | char *buffer; | |
af6aa1b9 | 406 | loff_t base = page_offset(page); |
09cbfeaf KS |
407 | int count = PAGE_SIZE; |
408 | int end_index = inode->i_size >> PAGE_SHIFT; | |
1da177e4 LT |
409 | int err; |
410 | ||
411 | if (page->index >= end_index) | |
09cbfeaf | 412 | count = inode->i_size & (PAGE_SIZE-1); |
1da177e4 LT |
413 | |
414 | buffer = kmap(page); | |
1da177e4 LT |
415 | |
416 | err = write_file(HOSTFS_I(inode)->fd, &base, buffer, count); | |
84b3db04 | 417 | if (err != count) { |
1da177e4 LT |
418 | ClearPageUptodate(page); |
419 | goto out; | |
420 | } | |
421 | ||
422 | if (base > inode->i_size) | |
423 | inode->i_size = base; | |
424 | ||
425 | if (PageError(page)) | |
426 | ClearPageError(page); | |
427 | err = 0; | |
428 | ||
429 | out: | |
430 | kunmap(page); | |
431 | ||
432 | unlock_page(page); | |
433 | return err; | |
434 | } | |
435 | ||
9e443bc3 | 436 | static int hostfs_readpage(struct file *file, struct page *page) |
1da177e4 LT |
437 | { |
438 | char *buffer; | |
af6aa1b9 | 439 | loff_t start = page_offset(page); |
b86b413a | 440 | int bytes_read, ret = 0; |
1da177e4 | 441 | |
1da177e4 | 442 | buffer = kmap(page); |
41761ddf | 443 | bytes_read = read_file(FILE_HOSTFS_I(file)->fd, &start, buffer, |
09cbfeaf | 444 | PAGE_SIZE); |
41761ddf | 445 | if (bytes_read < 0) { |
b86b413a RW |
446 | ClearPageUptodate(page); |
447 | SetPageError(page); | |
41761ddf | 448 | ret = bytes_read; |
84b3db04 | 449 | goto out; |
41761ddf | 450 | } |
1da177e4 | 451 | |
09cbfeaf | 452 | memset(buffer + bytes_read, 0, PAGE_SIZE - bytes_read); |
1da177e4 | 453 | |
b86b413a | 454 | ClearPageError(page); |
1da177e4 | 455 | SetPageUptodate(page); |
b86b413a | 456 | |
1da177e4 | 457 | out: |
b86b413a | 458 | flush_dcache_page(page); |
1da177e4 LT |
459 | kunmap(page); |
460 | unlock_page(page); | |
41761ddf | 461 | return ret; |
1da177e4 LT |
462 | } |
463 | ||
9e443bc3 JH |
464 | static int hostfs_write_begin(struct file *file, struct address_space *mapping, |
465 | loff_t pos, unsigned len, unsigned flags, | |
466 | struct page **pagep, void **fsdata) | |
1da177e4 | 467 | { |
09cbfeaf | 468 | pgoff_t index = pos >> PAGE_SHIFT; |
1da177e4 | 469 | |
54566b2c | 470 | *pagep = grab_cache_page_write_begin(mapping, index, flags); |
ae361ff4 NP |
471 | if (!*pagep) |
472 | return -ENOMEM; | |
473 | return 0; | |
1da177e4 LT |
474 | } |
475 | ||
9e443bc3 JH |
476 | static int hostfs_write_end(struct file *file, struct address_space *mapping, |
477 | loff_t pos, unsigned len, unsigned copied, | |
478 | struct page *page, void *fsdata) | |
1da177e4 | 479 | { |
1da177e4 | 480 | struct inode *inode = mapping->host; |
ae361ff4 | 481 | void *buffer; |
09cbfeaf | 482 | unsigned from = pos & (PAGE_SIZE - 1); |
ae361ff4 | 483 | int err; |
1da177e4 | 484 | |
1da177e4 | 485 | buffer = kmap(page); |
ae361ff4 NP |
486 | err = write_file(FILE_HOSTFS_I(file)->fd, &pos, buffer + from, copied); |
487 | kunmap(page); | |
30f04a4e | 488 | |
09cbfeaf | 489 | if (!PageUptodate(page) && err == PAGE_SIZE) |
ae361ff4 | 490 | SetPageUptodate(page); |
30f04a4e | 491 | |
84b3db04 JD |
492 | /* |
493 | * If err > 0, write_file has added err to pos, so we are comparing | |
ae361ff4 NP |
494 | * i_size against the last byte written. |
495 | */ | |
496 | if (err > 0 && (pos > inode->i_size)) | |
497 | inode->i_size = pos; | |
498 | unlock_page(page); | |
09cbfeaf | 499 | put_page(page); |
1da177e4 | 500 | |
f1adc05e | 501 | return err; |
1da177e4 LT |
502 | } |
503 | ||
f5e54d6e | 504 | static const struct address_space_operations hostfs_aops = { |
1da177e4 LT |
505 | .writepage = hostfs_writepage, |
506 | .readpage = hostfs_readpage, | |
ffa0aea6 | 507 | .set_page_dirty = __set_page_dirty_nobuffers, |
ae361ff4 NP |
508 | .write_begin = hostfs_write_begin, |
509 | .write_end = hostfs_write_end, | |
1da177e4 LT |
510 | }; |
511 | ||
4754b825 | 512 | static int read_name(struct inode *ino, char *name) |
1da177e4 | 513 | { |
4754b825 AV |
514 | dev_t rdev; |
515 | struct hostfs_stat st; | |
516 | int err = stat_file(name, &st, -1); | |
517 | if (err) | |
518 | return err; | |
1da177e4 | 519 | |
5e2df28c | 520 | /* Reencode maj and min with the kernel encoding.*/ |
4754b825 | 521 | rdev = MKDEV(st.maj, st.min); |
1da177e4 | 522 | |
4754b825 AV |
523 | switch (st.mode & S_IFMT) { |
524 | case S_IFLNK: | |
d0352d3e | 525 | ino->i_op = &hostfs_link_iops; |
1da177e4 | 526 | break; |
4754b825 AV |
527 | case S_IFDIR: |
528 | ino->i_op = &hostfs_dir_iops; | |
529 | ino->i_fop = &hostfs_dir_fops; | |
1da177e4 | 530 | break; |
4754b825 AV |
531 | case S_IFCHR: |
532 | case S_IFBLK: | |
533 | case S_IFIFO: | |
534 | case S_IFSOCK: | |
535 | init_special_inode(ino, st.mode & S_IFMT, rdev); | |
536 | ino->i_op = &hostfs_iops; | |
1da177e4 | 537 | break; |
2ad2dca6 | 538 | case S_IFREG: |
4754b825 AV |
539 | ino->i_op = &hostfs_iops; |
540 | ino->i_fop = &hostfs_file_fops; | |
541 | ino->i_mapping->a_ops = &hostfs_aops; | |
2ad2dca6 RW |
542 | break; |
543 | default: | |
544 | return -EIO; | |
1da177e4 | 545 | } |
4754b825 AV |
546 | |
547 | ino->i_ino = st.ino; | |
548 | ino->i_mode = st.mode; | |
bfe86848 | 549 | set_nlink(ino, st.nlink); |
29f82ae5 EB |
550 | i_uid_write(ino, st.uid); |
551 | i_gid_write(ino, st.gid); | |
95582b00 DD |
552 | ino->i_atime = timespec_to_timespec64(st.atime); |
553 | ino->i_mtime = timespec_to_timespec64(st.mtime); | |
554 | ino->i_ctime = timespec_to_timespec64(st.ctime); | |
4754b825 AV |
555 | ino->i_size = st.size; |
556 | ino->i_blocks = st.blocks; | |
557 | return 0; | |
1da177e4 LT |
558 | } |
559 | ||
9e443bc3 JH |
560 | static int hostfs_create(struct inode *dir, struct dentry *dentry, umode_t mode, |
561 | bool excl) | |
1da177e4 LT |
562 | { |
563 | struct inode *inode; | |
564 | char *name; | |
565 | int error, fd; | |
566 | ||
0a370e5d DH |
567 | inode = hostfs_iget(dir->i_sb); |
568 | if (IS_ERR(inode)) { | |
569 | error = PTR_ERR(inode); | |
84b3db04 | 570 | goto out; |
0a370e5d | 571 | } |
1da177e4 | 572 | |
1da177e4 | 573 | error = -ENOMEM; |
c5322220 | 574 | name = dentry_name(dentry); |
84b3db04 | 575 | if (name == NULL) |
1da177e4 LT |
576 | goto out_put; |
577 | ||
a718c922 | 578 | fd = file_create(name, mode & 0777); |
4754b825 | 579 | if (fd < 0) |
1da177e4 | 580 | error = fd; |
4754b825 | 581 | else |
5e2df28c | 582 | error = read_name(inode, name); |
1da177e4 | 583 | |
e9193059 | 584 | __putname(name); |
84b3db04 | 585 | if (error) |
1da177e4 LT |
586 | goto out_put; |
587 | ||
588 | HOSTFS_I(inode)->fd = fd; | |
589 | HOSTFS_I(inode)->mode = FMODE_READ | FMODE_WRITE; | |
590 | d_instantiate(dentry, inode); | |
f1adc05e | 591 | return 0; |
1da177e4 LT |
592 | |
593 | out_put: | |
594 | iput(inode); | |
595 | out: | |
f1adc05e | 596 | return error; |
1da177e4 LT |
597 | } |
598 | ||
9e443bc3 JH |
599 | static struct dentry *hostfs_lookup(struct inode *ino, struct dentry *dentry, |
600 | unsigned int flags) | |
1da177e4 LT |
601 | { |
602 | struct inode *inode; | |
603 | char *name; | |
604 | int err; | |
605 | ||
0a370e5d | 606 | inode = hostfs_iget(ino->i_sb); |
50f30740 | 607 | if (IS_ERR(inode)) |
1da177e4 LT |
608 | goto out; |
609 | ||
1da177e4 | 610 | err = -ENOMEM; |
c5322220 | 611 | name = dentry_name(dentry); |
50f30740 AV |
612 | if (name) { |
613 | err = read_name(inode, name); | |
614 | __putname(name); | |
615 | } | |
616 | if (err) { | |
1da177e4 | 617 | iput(inode); |
50f30740 | 618 | inode = (err == -ENOENT) ? NULL : ERR_PTR(err); |
1da177e4 | 619 | } |
1da177e4 | 620 | out: |
50f30740 | 621 | return d_splice_alias(inode, dentry); |
1da177e4 LT |
622 | } |
623 | ||
9e443bc3 JH |
624 | static int hostfs_link(struct dentry *to, struct inode *ino, |
625 | struct dentry *from) | |
1da177e4 | 626 | { |
f1adc05e JD |
627 | char *from_name, *to_name; |
628 | int err; | |
1da177e4 | 629 | |
c5322220 | 630 | if ((from_name = dentry_name(from)) == NULL) |
f1adc05e | 631 | return -ENOMEM; |
c5322220 | 632 | to_name = dentry_name(to); |
84b3db04 | 633 | if (to_name == NULL) { |
e9193059 | 634 | __putname(from_name); |
f1adc05e | 635 | return -ENOMEM; |
1da177e4 | 636 | } |
f1adc05e | 637 | err = link_file(to_name, from_name); |
e9193059 AV |
638 | __putname(from_name); |
639 | __putname(to_name); | |
f1adc05e | 640 | return err; |
1da177e4 LT |
641 | } |
642 | ||
9e443bc3 | 643 | static int hostfs_unlink(struct inode *ino, struct dentry *dentry) |
1da177e4 LT |
644 | { |
645 | char *file; | |
646 | int err; | |
647 | ||
84b3db04 | 648 | if (append) |
f1adc05e | 649 | return -EPERM; |
1da177e4 | 650 | |
f8d7e187 AV |
651 | if ((file = dentry_name(dentry)) == NULL) |
652 | return -ENOMEM; | |
653 | ||
1da177e4 | 654 | err = unlink_file(file); |
e9193059 | 655 | __putname(file); |
f1adc05e | 656 | return err; |
1da177e4 LT |
657 | } |
658 | ||
9e443bc3 JH |
659 | static int hostfs_symlink(struct inode *ino, struct dentry *dentry, |
660 | const char *to) | |
1da177e4 LT |
661 | { |
662 | char *file; | |
663 | int err; | |
664 | ||
c5322220 | 665 | if ((file = dentry_name(dentry)) == NULL) |
f1adc05e | 666 | return -ENOMEM; |
1da177e4 | 667 | err = make_symlink(file, to); |
e9193059 | 668 | __putname(file); |
f1adc05e | 669 | return err; |
1da177e4 LT |
670 | } |
671 | ||
9e443bc3 | 672 | static int hostfs_mkdir(struct inode *ino, struct dentry *dentry, umode_t mode) |
1da177e4 LT |
673 | { |
674 | char *file; | |
675 | int err; | |
676 | ||
c5322220 | 677 | if ((file = dentry_name(dentry)) == NULL) |
f1adc05e | 678 | return -ENOMEM; |
1da177e4 | 679 | err = do_mkdir(file, mode); |
e9193059 | 680 | __putname(file); |
f1adc05e | 681 | return err; |
1da177e4 LT |
682 | } |
683 | ||
9e443bc3 | 684 | static int hostfs_rmdir(struct inode *ino, struct dentry *dentry) |
1da177e4 LT |
685 | { |
686 | char *file; | |
687 | int err; | |
688 | ||
c5322220 | 689 | if ((file = dentry_name(dentry)) == NULL) |
f1adc05e | 690 | return -ENOMEM; |
6380161c | 691 | err = hostfs_do_rmdir(file); |
e9193059 | 692 | __putname(file); |
f1adc05e | 693 | return err; |
1da177e4 LT |
694 | } |
695 | ||
1a67aafb | 696 | static int hostfs_mknod(struct inode *dir, struct dentry *dentry, umode_t mode, dev_t dev) |
1da177e4 LT |
697 | { |
698 | struct inode *inode; | |
699 | char *name; | |
0a370e5d | 700 | int err; |
1da177e4 | 701 | |
0a370e5d DH |
702 | inode = hostfs_iget(dir->i_sb); |
703 | if (IS_ERR(inode)) { | |
704 | err = PTR_ERR(inode); | |
1da177e4 | 705 | goto out; |
0a370e5d | 706 | } |
1da177e4 | 707 | |
1da177e4 | 708 | err = -ENOMEM; |
c5322220 | 709 | name = dentry_name(dentry); |
84b3db04 | 710 | if (name == NULL) |
1da177e4 LT |
711 | goto out_put; |
712 | ||
713 | init_special_inode(inode, mode, dev); | |
88f6cd0c | 714 | err = do_mknod(name, mode, MAJOR(dev), MINOR(dev)); |
9f2dfda2 | 715 | if (err) |
1da177e4 LT |
716 | goto out_free; |
717 | ||
718 | err = read_name(inode, name); | |
e9193059 | 719 | __putname(name); |
5e2df28c AV |
720 | if (err) |
721 | goto out_put; | |
1da177e4 LT |
722 | |
723 | d_instantiate(dentry, inode); | |
f1adc05e | 724 | return 0; |
1da177e4 LT |
725 | |
726 | out_free: | |
e9193059 | 727 | __putname(name); |
1da177e4 LT |
728 | out_put: |
729 | iput(inode); | |
730 | out: | |
f1adc05e | 731 | return err; |
1da177e4 LT |
732 | } |
733 | ||
9a423bb6 MS |
734 | static int hostfs_rename2(struct inode *old_dir, struct dentry *old_dentry, |
735 | struct inode *new_dir, struct dentry *new_dentry, | |
736 | unsigned int flags) | |
1da177e4 | 737 | { |
9a423bb6 | 738 | char *old_name, *new_name; |
1da177e4 LT |
739 | int err; |
740 | ||
9a423bb6 MS |
741 | if (flags & ~(RENAME_NOREPLACE | RENAME_EXCHANGE)) |
742 | return -EINVAL; | |
743 | ||
744 | old_name = dentry_name(old_dentry); | |
745 | if (old_name == NULL) | |
f1adc05e | 746 | return -ENOMEM; |
9a423bb6 MS |
747 | new_name = dentry_name(new_dentry); |
748 | if (new_name == NULL) { | |
749 | __putname(old_name); | |
f1adc05e | 750 | return -ENOMEM; |
1da177e4 | 751 | } |
9a423bb6 MS |
752 | if (!flags) |
753 | err = rename_file(old_name, new_name); | |
754 | else | |
755 | err = rename2_file(old_name, new_name, flags); | |
756 | ||
757 | __putname(old_name); | |
758 | __putname(new_name); | |
f1adc05e | 759 | return err; |
1da177e4 LT |
760 | } |
761 | ||
9e443bc3 | 762 | static int hostfs_permission(struct inode *ino, int desired) |
1da177e4 LT |
763 | { |
764 | char *name; | |
765 | int r = 0, w = 0, x = 0, err; | |
766 | ||
10556cb2 | 767 | if (desired & MAY_NOT_BLOCK) |
b74c79e9 NP |
768 | return -ECHILD; |
769 | ||
1da177e4 LT |
770 | if (desired & MAY_READ) r = 1; |
771 | if (desired & MAY_WRITE) w = 1; | |
772 | if (desired & MAY_EXEC) x = 1; | |
c5322220 | 773 | name = inode_name(ino); |
f1adc05e JD |
774 | if (name == NULL) |
775 | return -ENOMEM; | |
1da177e4 LT |
776 | |
777 | if (S_ISCHR(ino->i_mode) || S_ISBLK(ino->i_mode) || | |
84b3db04 | 778 | S_ISFIFO(ino->i_mode) || S_ISSOCK(ino->i_mode)) |
1da177e4 LT |
779 | err = 0; |
780 | else | |
781 | err = access_file(name, r, w, x); | |
e9193059 | 782 | __putname(name); |
84b3db04 | 783 | if (!err) |
2830ba7f | 784 | err = generic_permission(ino, desired); |
1da177e4 LT |
785 | return err; |
786 | } | |
787 | ||
9e443bc3 | 788 | static int hostfs_setattr(struct dentry *dentry, struct iattr *attr) |
1da177e4 | 789 | { |
2b0143b5 | 790 | struct inode *inode = d_inode(dentry); |
1da177e4 LT |
791 | struct hostfs_iattr attrs; |
792 | char *name; | |
793 | int err; | |
794 | ||
1025774c | 795 | int fd = HOSTFS_I(inode)->fd; |
5822b7fa | 796 | |
31051c85 | 797 | err = setattr_prepare(dentry, attr); |
1da177e4 LT |
798 | if (err) |
799 | return err; | |
800 | ||
84b3db04 | 801 | if (append) |
1da177e4 LT |
802 | attr->ia_valid &= ~ATTR_SIZE; |
803 | ||
804 | attrs.ia_valid = 0; | |
84b3db04 | 805 | if (attr->ia_valid & ATTR_MODE) { |
1da177e4 LT |
806 | attrs.ia_valid |= HOSTFS_ATTR_MODE; |
807 | attrs.ia_mode = attr->ia_mode; | |
808 | } | |
84b3db04 | 809 | if (attr->ia_valid & ATTR_UID) { |
1da177e4 | 810 | attrs.ia_valid |= HOSTFS_ATTR_UID; |
29f82ae5 | 811 | attrs.ia_uid = from_kuid(&init_user_ns, attr->ia_uid); |
1da177e4 | 812 | } |
84b3db04 | 813 | if (attr->ia_valid & ATTR_GID) { |
1da177e4 | 814 | attrs.ia_valid |= HOSTFS_ATTR_GID; |
29f82ae5 | 815 | attrs.ia_gid = from_kgid(&init_user_ns, attr->ia_gid); |
1da177e4 | 816 | } |
84b3db04 | 817 | if (attr->ia_valid & ATTR_SIZE) { |
1da177e4 LT |
818 | attrs.ia_valid |= HOSTFS_ATTR_SIZE; |
819 | attrs.ia_size = attr->ia_size; | |
820 | } | |
84b3db04 | 821 | if (attr->ia_valid & ATTR_ATIME) { |
1da177e4 | 822 | attrs.ia_valid |= HOSTFS_ATTR_ATIME; |
95582b00 | 823 | attrs.ia_atime = timespec64_to_timespec(attr->ia_atime); |
1da177e4 | 824 | } |
84b3db04 | 825 | if (attr->ia_valid & ATTR_MTIME) { |
1da177e4 | 826 | attrs.ia_valid |= HOSTFS_ATTR_MTIME; |
95582b00 | 827 | attrs.ia_mtime = timespec64_to_timespec(attr->ia_mtime); |
1da177e4 | 828 | } |
84b3db04 | 829 | if (attr->ia_valid & ATTR_CTIME) { |
1da177e4 | 830 | attrs.ia_valid |= HOSTFS_ATTR_CTIME; |
95582b00 | 831 | attrs.ia_ctime = timespec64_to_timespec(attr->ia_ctime); |
1da177e4 | 832 | } |
84b3db04 | 833 | if (attr->ia_valid & ATTR_ATIME_SET) { |
1da177e4 LT |
834 | attrs.ia_valid |= HOSTFS_ATTR_ATIME_SET; |
835 | } | |
84b3db04 | 836 | if (attr->ia_valid & ATTR_MTIME_SET) { |
1da177e4 LT |
837 | attrs.ia_valid |= HOSTFS_ATTR_MTIME_SET; |
838 | } | |
c5322220 | 839 | name = dentry_name(dentry); |
84b3db04 | 840 | if (name == NULL) |
f1adc05e | 841 | return -ENOMEM; |
5822b7fa | 842 | err = set_attr(name, &attrs, fd); |
e9193059 | 843 | __putname(name); |
84b3db04 | 844 | if (err) |
f1adc05e | 845 | return err; |
1da177e4 | 846 | |
1025774c | 847 | if ((attr->ia_valid & ATTR_SIZE) && |
bc077320 | 848 | attr->ia_size != i_size_read(inode)) |
3be2be0a | 849 | truncate_setsize(inode, attr->ia_size); |
1025774c CH |
850 | |
851 | setattr_copy(inode, attr); | |
852 | mark_inode_dirty(inode); | |
853 | return 0; | |
1da177e4 LT |
854 | } |
855 | ||
92e1d5be | 856 | static const struct inode_operations hostfs_iops = { |
1da177e4 LT |
857 | .permission = hostfs_permission, |
858 | .setattr = hostfs_setattr, | |
1da177e4 LT |
859 | }; |
860 | ||
92e1d5be | 861 | static const struct inode_operations hostfs_dir_iops = { |
1da177e4 LT |
862 | .create = hostfs_create, |
863 | .lookup = hostfs_lookup, | |
864 | .link = hostfs_link, | |
865 | .unlink = hostfs_unlink, | |
866 | .symlink = hostfs_symlink, | |
867 | .mkdir = hostfs_mkdir, | |
868 | .rmdir = hostfs_rmdir, | |
869 | .mknod = hostfs_mknod, | |
2773bf00 | 870 | .rename = hostfs_rename2, |
1da177e4 LT |
871 | .permission = hostfs_permission, |
872 | .setattr = hostfs_setattr, | |
1da177e4 LT |
873 | }; |
874 | ||
6b255391 | 875 | static const char *hostfs_get_link(struct dentry *dentry, |
fceef393 AV |
876 | struct inode *inode, |
877 | struct delayed_call *done) | |
d0352d3e | 878 | { |
6b255391 AV |
879 | char *link; |
880 | if (!dentry) | |
881 | return ERR_PTR(-ECHILD); | |
fceef393 | 882 | link = kmalloc(PATH_MAX, GFP_KERNEL); |
d0352d3e AV |
883 | if (link) { |
884 | char *path = dentry_name(dentry); | |
885 | int err = -ENOMEM; | |
886 | if (path) { | |
3b6036d1 | 887 | err = hostfs_do_readlink(path, link, PATH_MAX); |
d0352d3e AV |
888 | if (err == PATH_MAX) |
889 | err = -E2BIG; | |
e9193059 | 890 | __putname(path); |
d0352d3e AV |
891 | } |
892 | if (err < 0) { | |
fceef393 | 893 | kfree(link); |
680baacb | 894 | return ERR_PTR(err); |
d0352d3e AV |
895 | } |
896 | } else { | |
680baacb | 897 | return ERR_PTR(-ENOMEM); |
1da177e4 | 898 | } |
d0352d3e | 899 | |
fceef393 AV |
900 | set_delayed_call(done, kfree_link, link); |
901 | return link; | |
1da177e4 LT |
902 | } |
903 | ||
d0352d3e | 904 | static const struct inode_operations hostfs_link_iops = { |
6b255391 | 905 | .get_link = hostfs_get_link, |
1da177e4 LT |
906 | }; |
907 | ||
908 | static int hostfs_fill_sb_common(struct super_block *sb, void *d, int silent) | |
909 | { | |
910 | struct inode *root_inode; | |
75e8defb | 911 | char *host_root_path, *req_root = d; |
1da177e4 LT |
912 | int err; |
913 | ||
914 | sb->s_blocksize = 1024; | |
915 | sb->s_blocksize_bits = 10; | |
916 | sb->s_magic = HOSTFS_SUPER_MAGIC; | |
917 | sb->s_op = &hostfs_sbops; | |
b26d4cd3 | 918 | sb->s_d_op = &simple_dentry_operations; |
752fa51e | 919 | sb->s_maxbytes = MAX_LFS_FILESIZE; |
1da177e4 | 920 | |
a6eb0be6 | 921 | /* NULL is printed as <NULL> by sprintf: avoid that. */ |
75e8defb PBG |
922 | if (req_root == NULL) |
923 | req_root = ""; | |
1da177e4 LT |
924 | |
925 | err = -ENOMEM; | |
601d2c38 AV |
926 | sb->s_fs_info = host_root_path = |
927 | kmalloc(strlen(root_ino) + strlen(req_root) + 2, GFP_KERNEL); | |
84b3db04 | 928 | if (host_root_path == NULL) |
1da177e4 LT |
929 | goto out; |
930 | ||
75e8defb | 931 | sprintf(host_root_path, "%s/%s", root_ino, req_root); |
1da177e4 | 932 | |
52b209f7 AV |
933 | root_inode = new_inode(sb); |
934 | if (!root_inode) | |
601d2c38 | 935 | goto out; |
1da177e4 | 936 | |
4754b825 AV |
937 | err = read_name(root_inode, host_root_path); |
938 | if (err) | |
939 | goto out_put; | |
52b209f7 | 940 | |
4754b825 | 941 | if (S_ISLNK(root_inode->i_mode)) { |
52b209f7 | 942 | char *name = follow_link(host_root_path); |
8a545f18 | 943 | if (IS_ERR(name)) { |
52b209f7 | 944 | err = PTR_ERR(name); |
8a545f18 DC |
945 | goto out_put; |
946 | } | |
947 | err = read_name(root_inode, name); | |
52b209f7 | 948 | kfree(name); |
4754b825 AV |
949 | if (err) |
950 | goto out_put; | |
52b209f7 | 951 | } |
1da177e4 | 952 | |
1da177e4 | 953 | err = -ENOMEM; |
48fde701 | 954 | sb->s_root = d_make_root(root_inode); |
84b3db04 | 955 | if (sb->s_root == NULL) |
48fde701 | 956 | goto out; |
1da177e4 | 957 | |
f1adc05e | 958 | return 0; |
1da177e4 | 959 | |
f1adc05e JD |
960 | out_put: |
961 | iput(root_inode); | |
f1adc05e JD |
962 | out: |
963 | return err; | |
1da177e4 LT |
964 | } |
965 | ||
3c26ff6e | 966 | static struct dentry *hostfs_read_sb(struct file_system_type *type, |
454e2398 | 967 | int flags, const char *dev_name, |
3c26ff6e | 968 | void *data) |
1da177e4 | 969 | { |
3c26ff6e | 970 | return mount_nodev(type, flags, data, hostfs_fill_sb_common); |
1da177e4 LT |
971 | } |
972 | ||
601d2c38 AV |
973 | static void hostfs_kill_sb(struct super_block *s) |
974 | { | |
975 | kill_anon_super(s); | |
976 | kfree(s->s_fs_info); | |
977 | } | |
978 | ||
1da177e4 LT |
979 | static struct file_system_type hostfs_type = { |
980 | .owner = THIS_MODULE, | |
981 | .name = "hostfs", | |
3c26ff6e | 982 | .mount = hostfs_read_sb, |
601d2c38 | 983 | .kill_sb = hostfs_kill_sb, |
1da177e4 LT |
984 | .fs_flags = 0, |
985 | }; | |
3e64fe5b | 986 | MODULE_ALIAS_FS("hostfs"); |
1da177e4 LT |
987 | |
988 | static int __init init_hostfs(void) | |
989 | { | |
f1adc05e | 990 | return register_filesystem(&hostfs_type); |
1da177e4 LT |
991 | } |
992 | ||
993 | static void __exit exit_hostfs(void) | |
994 | { | |
995 | unregister_filesystem(&hostfs_type); | |
996 | } | |
997 | ||
998 | module_init(init_hostfs) | |
999 | module_exit(exit_hostfs) | |
1000 | MODULE_LICENSE("GPL"); |