Commit | Line | Data |
---|---|---|
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> |
1da177e4 | 10 | #include <linux/module.h> |
84b3db04 | 11 | #include <linux/mm.h> |
1da177e4 | 12 | #include <linux/pagemap.h> |
1da177e4 | 13 | #include <linux/statfs.h> |
5a0e3ad6 | 14 | #include <linux/slab.h> |
dd2cc4df | 15 | #include <linux/seq_file.h> |
6966a977 | 16 | #include <linux/mount.h> |
1da177e4 | 17 | #include "hostfs.h" |
1da177e4 | 18 | #include "init.h" |
84b3db04 | 19 | #include "kern.h" |
1da177e4 LT |
20 | |
21 | struct hostfs_inode_info { | |
22 | char *host_filename; | |
23 | int fd; | |
aeb5d727 | 24 | fmode_t mode; |
1da177e4 LT |
25 | struct inode vfs_inode; |
26 | }; | |
27 | ||
28 | static inline struct hostfs_inode_info *HOSTFS_I(struct inode *inode) | |
29 | { | |
f1adc05e | 30 | return list_entry(inode, struct hostfs_inode_info, vfs_inode); |
1da177e4 LT |
31 | } |
32 | ||
680b0da9 | 33 | #define FILE_HOSTFS_I(file) HOSTFS_I((file)->f_path.dentry->d_inode) |
1da177e4 | 34 | |
e16404ed | 35 | static int hostfs_d_delete(struct dentry *dentry) |
1da177e4 | 36 | { |
f1adc05e | 37 | return 1; |
1da177e4 LT |
38 | } |
39 | ||
e16404ed | 40 | static const struct dentry_operations hostfs_dentry_ops = { |
1da177e4 LT |
41 | .d_delete = hostfs_d_delete, |
42 | }; | |
43 | ||
44 | /* Changed in hostfs_args before the kernel starts running */ | |
a6eb0be6 | 45 | static char *root_ino = ""; |
1da177e4 LT |
46 | static int append = 0; |
47 | ||
48 | #define HOSTFS_SUPER_MAGIC 0x00c0ffee | |
49 | ||
92e1d5be AV |
50 | static const struct inode_operations hostfs_iops; |
51 | static const struct inode_operations hostfs_dir_iops; | |
f5e54d6e | 52 | static const struct address_space_operations hostfs_link_aops; |
1da177e4 LT |
53 | |
54 | #ifndef MODULE | |
55 | static int __init hostfs_args(char *options, int *add) | |
56 | { | |
57 | char *ptr; | |
58 | ||
59 | ptr = strchr(options, ','); | |
84b3db04 | 60 | if (ptr != NULL) |
1da177e4 | 61 | *ptr++ = '\0'; |
84b3db04 | 62 | if (*options != '\0') |
1da177e4 LT |
63 | root_ino = options; |
64 | ||
65 | options = ptr; | |
84b3db04 | 66 | while (options) { |
1da177e4 | 67 | ptr = strchr(options, ','); |
84b3db04 | 68 | if (ptr != NULL) |
1da177e4 | 69 | *ptr++ = '\0'; |
84b3db04 JD |
70 | if (*options != '\0') { |
71 | if (!strcmp(options, "append")) | |
1da177e4 LT |
72 | append = 1; |
73 | else printf("hostfs_args - unsupported option - %s\n", | |
74 | options); | |
75 | } | |
76 | options = ptr; | |
77 | } | |
f1adc05e | 78 | return 0; |
1da177e4 LT |
79 | } |
80 | ||
81 | __uml_setup("hostfs=", hostfs_args, | |
82 | "hostfs=<root dir>,<flags>,...\n" | |
83 | " This is used to set hostfs parameters. The root directory argument\n" | |
84 | " is used to confine all hostfs mounts to within the specified directory\n" | |
85 | " tree on the host. If this isn't specified, then a user inside UML can\n" | |
86 | " mount anything on the host that's accessible to the user that's running\n" | |
87 | " it.\n" | |
88 | " The only flag currently supported is 'append', which specifies that all\n" | |
89 | " files opened by hostfs will be opened in append mode.\n\n" | |
90 | ); | |
91 | #endif | |
92 | ||
93 | static char *dentry_name(struct dentry *dentry, int extra) | |
94 | { | |
95 | struct dentry *parent; | |
96 | char *root, *name; | |
97 | int len; | |
98 | ||
99 | len = 0; | |
100 | parent = dentry; | |
84b3db04 | 101 | while (parent->d_parent != parent) { |
1da177e4 LT |
102 | len += parent->d_name.len + 1; |
103 | parent = parent->d_parent; | |
104 | } | |
105 | ||
106 | root = HOSTFS_I(parent->d_inode)->host_filename; | |
107 | len += strlen(root); | |
108 | name = kmalloc(len + extra + 1, GFP_KERNEL); | |
84b3db04 | 109 | if (name == NULL) |
f1adc05e | 110 | return NULL; |
1da177e4 LT |
111 | |
112 | name[len] = '\0'; | |
113 | parent = dentry; | |
84b3db04 | 114 | while (parent->d_parent != parent) { |
1da177e4 LT |
115 | len -= parent->d_name.len + 1; |
116 | name[len] = '/'; | |
117 | strncpy(&name[len + 1], parent->d_name.name, | |
118 | parent->d_name.len); | |
119 | parent = parent->d_parent; | |
120 | } | |
121 | strncpy(name, root, strlen(root)); | |
f1adc05e | 122 | return name; |
1da177e4 LT |
123 | } |
124 | ||
125 | static char *inode_name(struct inode *ino, int extra) | |
126 | { | |
127 | struct dentry *dentry; | |
128 | ||
129 | dentry = list_entry(ino->i_dentry.next, struct dentry, d_alias); | |
f1adc05e | 130 | return dentry_name(dentry, extra); |
1da177e4 LT |
131 | } |
132 | ||
133 | static int read_name(struct inode *ino, char *name) | |
134 | { | |
84b3db04 JD |
135 | /* |
136 | * The non-int inode fields are copied into ints by stat_file and | |
1da177e4 LT |
137 | * then copied into the inode because passing the actual pointers |
138 | * in and having them treated as int * breaks on big-endian machines | |
139 | */ | |
140 | int err; | |
141 | int i_mode, i_nlink, i_blksize; | |
142 | unsigned long long i_size; | |
143 | unsigned long long i_ino; | |
144 | unsigned long long i_blocks; | |
145 | ||
146 | err = stat_file(name, &i_ino, &i_mode, &i_nlink, &ino->i_uid, | |
147 | &ino->i_gid, &i_size, &ino->i_atime, &ino->i_mtime, | |
5822b7fa | 148 | &ino->i_ctime, &i_blksize, &i_blocks, -1); |
84b3db04 | 149 | if (err) |
f1adc05e | 150 | return err; |
1da177e4 LT |
151 | |
152 | ino->i_ino = i_ino; | |
153 | ino->i_mode = i_mode; | |
154 | ino->i_nlink = i_nlink; | |
155 | ino->i_size = i_size; | |
1da177e4 | 156 | ino->i_blocks = i_blocks; |
f1adc05e | 157 | return 0; |
1da177e4 LT |
158 | } |
159 | ||
160 | static char *follow_link(char *link) | |
161 | { | |
162 | int len, n; | |
163 | char *name, *resolved, *end; | |
164 | ||
165 | len = 64; | |
84b3db04 | 166 | while (1) { |
1da177e4 LT |
167 | n = -ENOMEM; |
168 | name = kmalloc(len, GFP_KERNEL); | |
84b3db04 | 169 | if (name == NULL) |
1da177e4 LT |
170 | goto out; |
171 | ||
ea7e743e | 172 | n = hostfs_do_readlink(link, name, len); |
84b3db04 | 173 | if (n < len) |
1da177e4 LT |
174 | break; |
175 | len *= 2; | |
176 | kfree(name); | |
177 | } | |
84b3db04 | 178 | if (n < 0) |
1da177e4 LT |
179 | goto out_free; |
180 | ||
84b3db04 | 181 | if (*name == '/') |
f1adc05e | 182 | return name; |
1da177e4 LT |
183 | |
184 | end = strrchr(link, '/'); | |
84b3db04 | 185 | if (end == NULL) |
f1adc05e | 186 | return name; |
1da177e4 LT |
187 | |
188 | *(end + 1) = '\0'; | |
189 | len = strlen(link) + strlen(name) + 1; | |
190 | ||
191 | resolved = kmalloc(len, GFP_KERNEL); | |
84b3db04 | 192 | if (resolved == NULL) { |
1da177e4 LT |
193 | n = -ENOMEM; |
194 | goto out_free; | |
195 | } | |
196 | ||
197 | sprintf(resolved, "%s%s", link, name); | |
198 | kfree(name); | |
199 | kfree(link); | |
f1adc05e | 200 | return resolved; |
1da177e4 LT |
201 | |
202 | out_free: | |
203 | kfree(name); | |
204 | out: | |
f1adc05e | 205 | return ERR_PTR(n); |
1da177e4 LT |
206 | } |
207 | ||
0a370e5d | 208 | static int hostfs_read_inode(struct inode *ino) |
1da177e4 LT |
209 | { |
210 | char *name; | |
211 | int err = 0; | |
212 | ||
84b3db04 JD |
213 | /* |
214 | * Unfortunately, we are called from iget() when we don't have a dentry | |
1da177e4 LT |
215 | * allocated yet. |
216 | */ | |
84b3db04 | 217 | if (list_empty(&ino->i_dentry)) |
1da177e4 LT |
218 | goto out; |
219 | ||
220 | err = -ENOMEM; | |
221 | name = inode_name(ino, 0); | |
84b3db04 | 222 | if (name == NULL) |
1da177e4 LT |
223 | goto out; |
224 | ||
84b3db04 | 225 | if (file_type(name, NULL, NULL) == OS_TYPE_SYMLINK) { |
1da177e4 | 226 | name = follow_link(name); |
84b3db04 | 227 | if (IS_ERR(name)) { |
1da177e4 LT |
228 | err = PTR_ERR(name); |
229 | goto out; | |
230 | } | |
231 | } | |
232 | ||
233 | err = read_name(ino, name); | |
234 | kfree(name); | |
235 | out: | |
f1adc05e | 236 | return err; |
1da177e4 LT |
237 | } |
238 | ||
0a370e5d DH |
239 | static struct inode *hostfs_iget(struct super_block *sb) |
240 | { | |
241 | struct inode *inode; | |
242 | long ret; | |
243 | ||
244 | inode = iget_locked(sb, 0); | |
245 | if (!inode) | |
246 | return ERR_PTR(-ENOMEM); | |
247 | if (inode->i_state & I_NEW) { | |
248 | ret = hostfs_read_inode(inode); | |
249 | if (ret < 0) { | |
250 | iget_failed(inode); | |
251 | return ERR_PTR(ret); | |
252 | } | |
253 | unlock_new_inode(inode); | |
254 | } | |
255 | return inode; | |
256 | } | |
257 | ||
726c3342 | 258 | int hostfs_statfs(struct dentry *dentry, struct kstatfs *sf) |
1da177e4 | 259 | { |
84b3db04 JD |
260 | /* |
261 | * do_statfs uses struct statfs64 internally, but the linux kernel | |
1da177e4 LT |
262 | * struct statfs still has 32-bit versions for most of these fields, |
263 | * so we convert them here | |
264 | */ | |
265 | int err; | |
266 | long long f_blocks; | |
267 | long long f_bfree; | |
268 | long long f_bavail; | |
269 | long long f_files; | |
270 | long long f_ffree; | |
271 | ||
726c3342 | 272 | err = do_statfs(HOSTFS_I(dentry->d_sb->s_root->d_inode)->host_filename, |
1da177e4 LT |
273 | &sf->f_bsize, &f_blocks, &f_bfree, &f_bavail, &f_files, |
274 | &f_ffree, &sf->f_fsid, sizeof(sf->f_fsid), | |
275 | &sf->f_namelen, sf->f_spare); | |
84b3db04 | 276 | if (err) |
f1adc05e | 277 | return err; |
1da177e4 LT |
278 | sf->f_blocks = f_blocks; |
279 | sf->f_bfree = f_bfree; | |
280 | sf->f_bavail = f_bavail; | |
281 | sf->f_files = f_files; | |
282 | sf->f_ffree = f_ffree; | |
283 | sf->f_type = HOSTFS_SUPER_MAGIC; | |
f1adc05e | 284 | return 0; |
1da177e4 LT |
285 | } |
286 | ||
287 | static struct inode *hostfs_alloc_inode(struct super_block *sb) | |
288 | { | |
289 | struct hostfs_inode_info *hi; | |
290 | ||
291 | hi = kmalloc(sizeof(*hi), GFP_KERNEL); | |
84b3db04 | 292 | if (hi == NULL) |
f1adc05e | 293 | return NULL; |
1da177e4 LT |
294 | |
295 | *hi = ((struct hostfs_inode_info) { .host_filename = NULL, | |
296 | .fd = -1, | |
297 | .mode = 0 }); | |
298 | inode_init_once(&hi->vfs_inode); | |
f1adc05e | 299 | return &hi->vfs_inode; |
1da177e4 LT |
300 | } |
301 | ||
302 | static void hostfs_delete_inode(struct inode *inode) | |
303 | { | |
fef26658 | 304 | truncate_inode_pages(&inode->i_data, 0); |
84b3db04 | 305 | if (HOSTFS_I(inode)->fd != -1) { |
1da177e4 LT |
306 | close_file(&HOSTFS_I(inode)->fd); |
307 | HOSTFS_I(inode)->fd = -1; | |
308 | } | |
309 | clear_inode(inode); | |
310 | } | |
311 | ||
312 | static void hostfs_destroy_inode(struct inode *inode) | |
313 | { | |
f99d49ad | 314 | kfree(HOSTFS_I(inode)->host_filename); |
1da177e4 | 315 | |
84b3db04 JD |
316 | /* |
317 | * XXX: This should not happen, probably. The check is here for | |
318 | * additional safety. | |
319 | */ | |
320 | if (HOSTFS_I(inode)->fd != -1) { | |
1da177e4 LT |
321 | close_file(&HOSTFS_I(inode)->fd); |
322 | printk(KERN_DEBUG "Closing host fd in .destroy_inode\n"); | |
323 | } | |
324 | ||
325 | kfree(HOSTFS_I(inode)); | |
326 | } | |
327 | ||
dd2cc4df MS |
328 | static int hostfs_show_options(struct seq_file *seq, struct vfsmount *vfs) |
329 | { | |
330 | struct inode *root = vfs->mnt_sb->s_root->d_inode; | |
331 | const char *root_path = HOSTFS_I(root)->host_filename; | |
332 | size_t offset = strlen(root_ino) + 1; | |
333 | ||
334 | if (strlen(root_path) > offset) | |
335 | seq_printf(seq, ",%s", root_path + offset); | |
336 | ||
337 | return 0; | |
338 | } | |
339 | ||
ee9b6d61 | 340 | static const struct super_operations hostfs_sbops = { |
1da177e4 LT |
341 | .alloc_inode = hostfs_alloc_inode, |
342 | .drop_inode = generic_delete_inode, | |
343 | .delete_inode = hostfs_delete_inode, | |
344 | .destroy_inode = hostfs_destroy_inode, | |
1da177e4 | 345 | .statfs = hostfs_statfs, |
dd2cc4df | 346 | .show_options = hostfs_show_options, |
1da177e4 LT |
347 | }; |
348 | ||
349 | int hostfs_readdir(struct file *file, void *ent, filldir_t filldir) | |
350 | { | |
351 | void *dir; | |
352 | char *name; | |
353 | unsigned long long next, ino; | |
354 | int error, len; | |
355 | ||
680b0da9 | 356 | name = dentry_name(file->f_path.dentry, 0); |
84b3db04 | 357 | if (name == NULL) |
f1adc05e | 358 | return -ENOMEM; |
1da177e4 LT |
359 | dir = open_dir(name, &error); |
360 | kfree(name); | |
84b3db04 | 361 | if (dir == NULL) |
f1adc05e | 362 | return -error; |
1da177e4 | 363 | next = file->f_pos; |
84b3db04 | 364 | while ((name = read_dir(dir, &next, &ino, &len)) != NULL) { |
1da177e4 LT |
365 | error = (*filldir)(ent, name, len, file->f_pos, |
366 | ino, DT_UNKNOWN); | |
84b3db04 | 367 | if (error) break; |
1da177e4 LT |
368 | file->f_pos = next; |
369 | } | |
370 | close_dir(dir); | |
f1adc05e | 371 | return 0; |
1da177e4 LT |
372 | } |
373 | ||
374 | int hostfs_file_open(struct inode *ino, struct file *file) | |
375 | { | |
376 | char *name; | |
aeb5d727 AV |
377 | fmode_t mode = 0; |
378 | int r = 0, w = 0, fd; | |
1da177e4 LT |
379 | |
380 | mode = file->f_mode & (FMODE_READ | FMODE_WRITE); | |
84b3db04 | 381 | if ((mode & HOSTFS_I(ino)->mode) == mode) |
f1adc05e | 382 | return 0; |
1da177e4 | 383 | |
84b3db04 JD |
384 | /* |
385 | * The file may already have been opened, but with the wrong access, | |
1da177e4 LT |
386 | * so this resets things and reopens the file with the new access. |
387 | */ | |
84b3db04 | 388 | if (HOSTFS_I(ino)->fd != -1) { |
1da177e4 LT |
389 | close_file(&HOSTFS_I(ino)->fd); |
390 | HOSTFS_I(ino)->fd = -1; | |
391 | } | |
392 | ||
393 | HOSTFS_I(ino)->mode |= mode; | |
84b3db04 | 394 | if (HOSTFS_I(ino)->mode & FMODE_READ) |
1da177e4 | 395 | r = 1; |
84b3db04 | 396 | if (HOSTFS_I(ino)->mode & FMODE_WRITE) |
1da177e4 | 397 | w = 1; |
84b3db04 | 398 | if (w) |
1da177e4 LT |
399 | r = 1; |
400 | ||
680b0da9 | 401 | name = dentry_name(file->f_path.dentry, 0); |
84b3db04 | 402 | if (name == NULL) |
f1adc05e | 403 | return -ENOMEM; |
1da177e4 LT |
404 | |
405 | fd = open_file(name, r, w, append); | |
406 | kfree(name); | |
84b3db04 | 407 | if (fd < 0) |
f1adc05e | 408 | return fd; |
1da177e4 LT |
409 | FILE_HOSTFS_I(file)->fd = fd; |
410 | ||
f1adc05e | 411 | return 0; |
1da177e4 LT |
412 | } |
413 | ||
414 | int hostfs_fsync(struct file *file, struct dentry *dentry, int datasync) | |
415 | { | |
a2d76bd8 | 416 | return fsync_file(HOSTFS_I(dentry->d_inode)->fd, datasync); |
1da177e4 LT |
417 | } |
418 | ||
4b6f5d20 | 419 | static const struct file_operations hostfs_file_fops = { |
1da177e4 | 420 | .llseek = generic_file_llseek, |
543ade1f | 421 | .read = do_sync_read, |
5ffc4ef4 | 422 | .splice_read = generic_file_splice_read, |
1da177e4 LT |
423 | .aio_read = generic_file_aio_read, |
424 | .aio_write = generic_file_aio_write, | |
543ade1f | 425 | .write = do_sync_write, |
1da177e4 LT |
426 | .mmap = generic_file_mmap, |
427 | .open = hostfs_file_open, | |
428 | .release = NULL, | |
429 | .fsync = hostfs_fsync, | |
430 | }; | |
431 | ||
4b6f5d20 | 432 | static const struct file_operations hostfs_dir_fops = { |
1da177e4 LT |
433 | .llseek = generic_file_llseek, |
434 | .readdir = hostfs_readdir, | |
435 | .read = generic_read_dir, | |
436 | }; | |
437 | ||
438 | int hostfs_writepage(struct page *page, struct writeback_control *wbc) | |
439 | { | |
440 | struct address_space *mapping = page->mapping; | |
441 | struct inode *inode = mapping->host; | |
442 | char *buffer; | |
443 | unsigned long long base; | |
444 | int count = PAGE_CACHE_SIZE; | |
445 | int end_index = inode->i_size >> PAGE_CACHE_SHIFT; | |
446 | int err; | |
447 | ||
448 | if (page->index >= end_index) | |
449 | count = inode->i_size & (PAGE_CACHE_SIZE-1); | |
450 | ||
451 | buffer = kmap(page); | |
452 | base = ((unsigned long long) page->index) << PAGE_CACHE_SHIFT; | |
453 | ||
454 | err = write_file(HOSTFS_I(inode)->fd, &base, buffer, count); | |
84b3db04 | 455 | if (err != count) { |
1da177e4 LT |
456 | ClearPageUptodate(page); |
457 | goto out; | |
458 | } | |
459 | ||
460 | if (base > inode->i_size) | |
461 | inode->i_size = base; | |
462 | ||
463 | if (PageError(page)) | |
464 | ClearPageError(page); | |
465 | err = 0; | |
466 | ||
467 | out: | |
468 | kunmap(page); | |
469 | ||
470 | unlock_page(page); | |
471 | return err; | |
472 | } | |
473 | ||
474 | int hostfs_readpage(struct file *file, struct page *page) | |
475 | { | |
476 | char *buffer; | |
477 | long long start; | |
478 | int err = 0; | |
479 | ||
480 | start = (long long) page->index << PAGE_CACHE_SHIFT; | |
481 | buffer = kmap(page); | |
482 | err = read_file(FILE_HOSTFS_I(file)->fd, &start, buffer, | |
483 | PAGE_CACHE_SIZE); | |
84b3db04 JD |
484 | if (err < 0) |
485 | goto out; | |
1da177e4 LT |
486 | |
487 | memset(&buffer[err], 0, PAGE_CACHE_SIZE - err); | |
488 | ||
489 | flush_dcache_page(page); | |
490 | SetPageUptodate(page); | |
491 | if (PageError(page)) ClearPageError(page); | |
492 | err = 0; | |
493 | out: | |
494 | kunmap(page); | |
495 | unlock_page(page); | |
f1adc05e | 496 | return err; |
1da177e4 LT |
497 | } |
498 | ||
ae361ff4 NP |
499 | int hostfs_write_begin(struct file *file, struct address_space *mapping, |
500 | loff_t pos, unsigned len, unsigned flags, | |
501 | struct page **pagep, void **fsdata) | |
1da177e4 | 502 | { |
ae361ff4 | 503 | pgoff_t index = pos >> PAGE_CACHE_SHIFT; |
1da177e4 | 504 | |
54566b2c | 505 | *pagep = grab_cache_page_write_begin(mapping, index, flags); |
ae361ff4 NP |
506 | if (!*pagep) |
507 | return -ENOMEM; | |
508 | return 0; | |
1da177e4 LT |
509 | } |
510 | ||
ae361ff4 NP |
511 | int hostfs_write_end(struct file *file, struct address_space *mapping, |
512 | loff_t pos, unsigned len, unsigned copied, | |
513 | struct page *page, void *fsdata) | |
1da177e4 | 514 | { |
1da177e4 | 515 | struct inode *inode = mapping->host; |
ae361ff4 NP |
516 | void *buffer; |
517 | unsigned from = pos & (PAGE_CACHE_SIZE - 1); | |
518 | int err; | |
1da177e4 | 519 | |
1da177e4 | 520 | buffer = kmap(page); |
ae361ff4 NP |
521 | err = write_file(FILE_HOSTFS_I(file)->fd, &pos, buffer + from, copied); |
522 | kunmap(page); | |
30f04a4e | 523 | |
ae361ff4 NP |
524 | if (!PageUptodate(page) && err == PAGE_CACHE_SIZE) |
525 | SetPageUptodate(page); | |
30f04a4e | 526 | |
84b3db04 JD |
527 | /* |
528 | * If err > 0, write_file has added err to pos, so we are comparing | |
ae361ff4 NP |
529 | * i_size against the last byte written. |
530 | */ | |
531 | if (err > 0 && (pos > inode->i_size)) | |
532 | inode->i_size = pos; | |
533 | unlock_page(page); | |
534 | page_cache_release(page); | |
1da177e4 | 535 | |
f1adc05e | 536 | return err; |
1da177e4 LT |
537 | } |
538 | ||
f5e54d6e | 539 | static const struct address_space_operations hostfs_aops = { |
1da177e4 LT |
540 | .writepage = hostfs_writepage, |
541 | .readpage = hostfs_readpage, | |
ffa0aea6 | 542 | .set_page_dirty = __set_page_dirty_nobuffers, |
ae361ff4 NP |
543 | .write_begin = hostfs_write_begin, |
544 | .write_end = hostfs_write_end, | |
1da177e4 LT |
545 | }; |
546 | ||
547 | static int init_inode(struct inode *inode, struct dentry *dentry) | |
548 | { | |
549 | char *name; | |
550 | int type, err = -ENOMEM; | |
551 | int maj, min; | |
552 | dev_t rdev = 0; | |
553 | ||
84b3db04 | 554 | if (dentry) { |
1da177e4 | 555 | name = dentry_name(dentry, 0); |
84b3db04 | 556 | if (name == NULL) |
1da177e4 LT |
557 | goto out; |
558 | type = file_type(name, &maj, &min); | |
84b3db04 | 559 | /* Reencode maj and min with the kernel encoding.*/ |
1da177e4 LT |
560 | rdev = MKDEV(maj, min); |
561 | kfree(name); | |
562 | } | |
563 | else type = OS_TYPE_DIR; | |
564 | ||
565 | err = 0; | |
84b3db04 | 566 | if (type == OS_TYPE_SYMLINK) |
1da177e4 | 567 | inode->i_op = &page_symlink_inode_operations; |
84b3db04 | 568 | else if (type == OS_TYPE_DIR) |
1da177e4 LT |
569 | inode->i_op = &hostfs_dir_iops; |
570 | else inode->i_op = &hostfs_iops; | |
571 | ||
84b3db04 | 572 | if (type == OS_TYPE_DIR) inode->i_fop = &hostfs_dir_fops; |
1da177e4 LT |
573 | else inode->i_fop = &hostfs_file_fops; |
574 | ||
84b3db04 | 575 | if (type == OS_TYPE_SYMLINK) |
1da177e4 LT |
576 | inode->i_mapping->a_ops = &hostfs_link_aops; |
577 | else inode->i_mapping->a_ops = &hostfs_aops; | |
578 | ||
579 | switch (type) { | |
580 | case OS_TYPE_CHARDEV: | |
581 | init_special_inode(inode, S_IFCHR, rdev); | |
582 | break; | |
583 | case OS_TYPE_BLOCKDEV: | |
584 | init_special_inode(inode, S_IFBLK, rdev); | |
585 | break; | |
586 | case OS_TYPE_FIFO: | |
587 | init_special_inode(inode, S_IFIFO, 0); | |
588 | break; | |
589 | case OS_TYPE_SOCK: | |
590 | init_special_inode(inode, S_IFSOCK, 0); | |
591 | break; | |
592 | } | |
593 | out: | |
f1adc05e | 594 | return err; |
1da177e4 LT |
595 | } |
596 | ||
597 | int hostfs_create(struct inode *dir, struct dentry *dentry, int mode, | |
84b3db04 | 598 | struct nameidata *nd) |
1da177e4 LT |
599 | { |
600 | struct inode *inode; | |
601 | char *name; | |
602 | int error, fd; | |
603 | ||
0a370e5d DH |
604 | inode = hostfs_iget(dir->i_sb); |
605 | if (IS_ERR(inode)) { | |
606 | error = PTR_ERR(inode); | |
84b3db04 | 607 | goto out; |
0a370e5d | 608 | } |
1da177e4 LT |
609 | |
610 | error = init_inode(inode, dentry); | |
84b3db04 | 611 | if (error) |
1da177e4 LT |
612 | goto out_put; |
613 | ||
614 | error = -ENOMEM; | |
615 | name = dentry_name(dentry, 0); | |
84b3db04 | 616 | if (name == NULL) |
1da177e4 LT |
617 | goto out_put; |
618 | ||
619 | fd = file_create(name, | |
620 | mode & S_IRUSR, mode & S_IWUSR, mode & S_IXUSR, | |
621 | mode & S_IRGRP, mode & S_IWGRP, mode & S_IXGRP, | |
622 | mode & S_IROTH, mode & S_IWOTH, mode & S_IXOTH); | |
84b3db04 | 623 | if (fd < 0) |
1da177e4 LT |
624 | error = fd; |
625 | else error = read_name(inode, name); | |
626 | ||
627 | kfree(name); | |
84b3db04 | 628 | if (error) |
1da177e4 LT |
629 | goto out_put; |
630 | ||
631 | HOSTFS_I(inode)->fd = fd; | |
632 | HOSTFS_I(inode)->mode = FMODE_READ | FMODE_WRITE; | |
633 | d_instantiate(dentry, inode); | |
f1adc05e | 634 | return 0; |
1da177e4 LT |
635 | |
636 | out_put: | |
637 | iput(inode); | |
638 | out: | |
f1adc05e | 639 | return error; |
1da177e4 LT |
640 | } |
641 | ||
642 | struct dentry *hostfs_lookup(struct inode *ino, struct dentry *dentry, | |
f1adc05e | 643 | struct nameidata *nd) |
1da177e4 LT |
644 | { |
645 | struct inode *inode; | |
646 | char *name; | |
647 | int err; | |
648 | ||
0a370e5d DH |
649 | inode = hostfs_iget(ino->i_sb); |
650 | if (IS_ERR(inode)) { | |
651 | err = PTR_ERR(inode); | |
1da177e4 | 652 | goto out; |
0a370e5d | 653 | } |
1da177e4 LT |
654 | |
655 | err = init_inode(inode, dentry); | |
84b3db04 | 656 | if (err) |
1da177e4 LT |
657 | goto out_put; |
658 | ||
659 | err = -ENOMEM; | |
660 | name = dentry_name(dentry, 0); | |
84b3db04 | 661 | if (name == NULL) |
1da177e4 LT |
662 | goto out_put; |
663 | ||
664 | err = read_name(inode, name); | |
665 | kfree(name); | |
84b3db04 | 666 | if (err == -ENOENT) { |
1da177e4 LT |
667 | iput(inode); |
668 | inode = NULL; | |
669 | } | |
84b3db04 | 670 | else if (err) |
1da177e4 LT |
671 | goto out_put; |
672 | ||
673 | d_add(dentry, inode); | |
674 | dentry->d_op = &hostfs_dentry_ops; | |
f1adc05e | 675 | return NULL; |
1da177e4 LT |
676 | |
677 | out_put: | |
678 | iput(inode); | |
679 | out: | |
f1adc05e | 680 | return ERR_PTR(err); |
1da177e4 LT |
681 | } |
682 | ||
683 | static char *inode_dentry_name(struct inode *ino, struct dentry *dentry) | |
684 | { | |
f1adc05e | 685 | char *file; |
1da177e4 LT |
686 | int len; |
687 | ||
688 | file = inode_name(ino, dentry->d_name.len + 1); | |
84b3db04 | 689 | if (file == NULL) |
f1adc05e JD |
690 | return NULL; |
691 | strcat(file, "/"); | |
1da177e4 | 692 | len = strlen(file); |
f1adc05e | 693 | strncat(file, dentry->d_name.name, dentry->d_name.len); |
1da177e4 | 694 | file[len + dentry->d_name.len] = '\0'; |
f1adc05e | 695 | return file; |
1da177e4 LT |
696 | } |
697 | ||
698 | int hostfs_link(struct dentry *to, struct inode *ino, struct dentry *from) | |
699 | { | |
f1adc05e JD |
700 | char *from_name, *to_name; |
701 | int err; | |
1da177e4 | 702 | |
84b3db04 | 703 | if ((from_name = inode_dentry_name(ino, from)) == NULL) |
f1adc05e JD |
704 | return -ENOMEM; |
705 | to_name = dentry_name(to, 0); | |
84b3db04 | 706 | if (to_name == NULL) { |
1da177e4 | 707 | kfree(from_name); |
f1adc05e | 708 | return -ENOMEM; |
1da177e4 | 709 | } |
f1adc05e JD |
710 | err = link_file(to_name, from_name); |
711 | kfree(from_name); | |
712 | kfree(to_name); | |
713 | return err; | |
1da177e4 LT |
714 | } |
715 | ||
716 | int hostfs_unlink(struct inode *ino, struct dentry *dentry) | |
717 | { | |
718 | char *file; | |
719 | int err; | |
720 | ||
84b3db04 | 721 | if ((file = inode_dentry_name(ino, dentry)) == NULL) |
f1adc05e | 722 | return -ENOMEM; |
84b3db04 | 723 | if (append) |
f1adc05e | 724 | return -EPERM; |
1da177e4 LT |
725 | |
726 | err = unlink_file(file); | |
727 | kfree(file); | |
f1adc05e | 728 | return err; |
1da177e4 LT |
729 | } |
730 | ||
731 | int hostfs_symlink(struct inode *ino, struct dentry *dentry, const char *to) | |
732 | { | |
733 | char *file; | |
734 | int err; | |
735 | ||
84b3db04 | 736 | if ((file = inode_dentry_name(ino, dentry)) == NULL) |
f1adc05e | 737 | return -ENOMEM; |
1da177e4 LT |
738 | err = make_symlink(file, to); |
739 | kfree(file); | |
f1adc05e | 740 | return err; |
1da177e4 LT |
741 | } |
742 | ||
743 | int hostfs_mkdir(struct inode *ino, struct dentry *dentry, int mode) | |
744 | { | |
745 | char *file; | |
746 | int err; | |
747 | ||
84b3db04 | 748 | if ((file = inode_dentry_name(ino, dentry)) == NULL) |
f1adc05e | 749 | return -ENOMEM; |
1da177e4 LT |
750 | err = do_mkdir(file, mode); |
751 | kfree(file); | |
f1adc05e | 752 | return err; |
1da177e4 LT |
753 | } |
754 | ||
755 | int hostfs_rmdir(struct inode *ino, struct dentry *dentry) | |
756 | { | |
757 | char *file; | |
758 | int err; | |
759 | ||
84b3db04 | 760 | if ((file = inode_dentry_name(ino, dentry)) == NULL) |
f1adc05e | 761 | return -ENOMEM; |
1da177e4 LT |
762 | err = do_rmdir(file); |
763 | kfree(file); | |
f1adc05e | 764 | return err; |
1da177e4 LT |
765 | } |
766 | ||
767 | int hostfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev) | |
768 | { | |
769 | struct inode *inode; | |
770 | char *name; | |
0a370e5d | 771 | int err; |
1da177e4 | 772 | |
0a370e5d DH |
773 | inode = hostfs_iget(dir->i_sb); |
774 | if (IS_ERR(inode)) { | |
775 | err = PTR_ERR(inode); | |
1da177e4 | 776 | goto out; |
0a370e5d | 777 | } |
1da177e4 LT |
778 | |
779 | err = init_inode(inode, dentry); | |
84b3db04 | 780 | if (err) |
1da177e4 LT |
781 | goto out_put; |
782 | ||
783 | err = -ENOMEM; | |
784 | name = dentry_name(dentry, 0); | |
84b3db04 | 785 | if (name == NULL) |
1da177e4 LT |
786 | goto out_put; |
787 | ||
788 | init_special_inode(inode, mode, dev); | |
88f6cd0c | 789 | err = do_mknod(name, mode, MAJOR(dev), MINOR(dev)); |
84b3db04 | 790 | if (err) |
1da177e4 LT |
791 | goto out_free; |
792 | ||
793 | err = read_name(inode, name); | |
794 | kfree(name); | |
84b3db04 | 795 | if (err) |
1da177e4 LT |
796 | goto out_put; |
797 | ||
798 | d_instantiate(dentry, inode); | |
f1adc05e | 799 | return 0; |
1da177e4 LT |
800 | |
801 | out_free: | |
802 | kfree(name); | |
803 | out_put: | |
804 | iput(inode); | |
805 | out: | |
f1adc05e | 806 | return err; |
1da177e4 LT |
807 | } |
808 | ||
809 | int hostfs_rename(struct inode *from_ino, struct dentry *from, | |
810 | struct inode *to_ino, struct dentry *to) | |
811 | { | |
812 | char *from_name, *to_name; | |
813 | int err; | |
814 | ||
84b3db04 | 815 | if ((from_name = inode_dentry_name(from_ino, from)) == NULL) |
f1adc05e | 816 | return -ENOMEM; |
84b3db04 | 817 | if ((to_name = inode_dentry_name(to_ino, to)) == NULL) { |
1da177e4 | 818 | kfree(from_name); |
f1adc05e | 819 | return -ENOMEM; |
1da177e4 LT |
820 | } |
821 | err = rename_file(from_name, to_name); | |
822 | kfree(from_name); | |
823 | kfree(to_name); | |
f1adc05e | 824 | return err; |
1da177e4 LT |
825 | } |
826 | ||
e6305c43 | 827 | int hostfs_permission(struct inode *ino, int desired) |
1da177e4 LT |
828 | { |
829 | char *name; | |
830 | int r = 0, w = 0, x = 0, err; | |
831 | ||
832 | if (desired & MAY_READ) r = 1; | |
833 | if (desired & MAY_WRITE) w = 1; | |
834 | if (desired & MAY_EXEC) x = 1; | |
835 | name = inode_name(ino, 0); | |
f1adc05e JD |
836 | if (name == NULL) |
837 | return -ENOMEM; | |
1da177e4 LT |
838 | |
839 | if (S_ISCHR(ino->i_mode) || S_ISBLK(ino->i_mode) || | |
84b3db04 | 840 | S_ISFIFO(ino->i_mode) || S_ISSOCK(ino->i_mode)) |
1da177e4 LT |
841 | err = 0; |
842 | else | |
843 | err = access_file(name, r, w, x); | |
844 | kfree(name); | |
84b3db04 | 845 | if (!err) |
1da177e4 LT |
846 | err = generic_permission(ino, desired, NULL); |
847 | return err; | |
848 | } | |
849 | ||
850 | int hostfs_setattr(struct dentry *dentry, struct iattr *attr) | |
851 | { | |
852 | struct hostfs_iattr attrs; | |
853 | char *name; | |
854 | int err; | |
855 | ||
5822b7fa AB |
856 | int fd = HOSTFS_I(dentry->d_inode)->fd; |
857 | ||
1da177e4 LT |
858 | err = inode_change_ok(dentry->d_inode, attr); |
859 | if (err) | |
860 | return err; | |
861 | ||
84b3db04 | 862 | if (append) |
1da177e4 LT |
863 | attr->ia_valid &= ~ATTR_SIZE; |
864 | ||
865 | attrs.ia_valid = 0; | |
84b3db04 | 866 | if (attr->ia_valid & ATTR_MODE) { |
1da177e4 LT |
867 | attrs.ia_valid |= HOSTFS_ATTR_MODE; |
868 | attrs.ia_mode = attr->ia_mode; | |
869 | } | |
84b3db04 | 870 | if (attr->ia_valid & ATTR_UID) { |
1da177e4 LT |
871 | attrs.ia_valid |= HOSTFS_ATTR_UID; |
872 | attrs.ia_uid = attr->ia_uid; | |
873 | } | |
84b3db04 | 874 | if (attr->ia_valid & ATTR_GID) { |
1da177e4 LT |
875 | attrs.ia_valid |= HOSTFS_ATTR_GID; |
876 | attrs.ia_gid = attr->ia_gid; | |
877 | } | |
84b3db04 | 878 | if (attr->ia_valid & ATTR_SIZE) { |
1da177e4 LT |
879 | attrs.ia_valid |= HOSTFS_ATTR_SIZE; |
880 | attrs.ia_size = attr->ia_size; | |
881 | } | |
84b3db04 | 882 | if (attr->ia_valid & ATTR_ATIME) { |
1da177e4 LT |
883 | attrs.ia_valid |= HOSTFS_ATTR_ATIME; |
884 | attrs.ia_atime = attr->ia_atime; | |
885 | } | |
84b3db04 | 886 | if (attr->ia_valid & ATTR_MTIME) { |
1da177e4 LT |
887 | attrs.ia_valid |= HOSTFS_ATTR_MTIME; |
888 | attrs.ia_mtime = attr->ia_mtime; | |
889 | } | |
84b3db04 | 890 | if (attr->ia_valid & ATTR_CTIME) { |
1da177e4 LT |
891 | attrs.ia_valid |= HOSTFS_ATTR_CTIME; |
892 | attrs.ia_ctime = attr->ia_ctime; | |
893 | } | |
84b3db04 | 894 | if (attr->ia_valid & ATTR_ATIME_SET) { |
1da177e4 LT |
895 | attrs.ia_valid |= HOSTFS_ATTR_ATIME_SET; |
896 | } | |
84b3db04 | 897 | if (attr->ia_valid & ATTR_MTIME_SET) { |
1da177e4 LT |
898 | attrs.ia_valid |= HOSTFS_ATTR_MTIME_SET; |
899 | } | |
900 | name = dentry_name(dentry, 0); | |
84b3db04 | 901 | if (name == NULL) |
f1adc05e | 902 | return -ENOMEM; |
5822b7fa | 903 | err = set_attr(name, &attrs, fd); |
1da177e4 | 904 | kfree(name); |
84b3db04 | 905 | if (err) |
f1adc05e | 906 | return err; |
1da177e4 | 907 | |
f1adc05e | 908 | return inode_setattr(dentry->d_inode, attr); |
1da177e4 LT |
909 | } |
910 | ||
92e1d5be | 911 | static const struct inode_operations hostfs_iops = { |
1da177e4 LT |
912 | .create = hostfs_create, |
913 | .link = hostfs_link, | |
914 | .unlink = hostfs_unlink, | |
915 | .symlink = hostfs_symlink, | |
916 | .mkdir = hostfs_mkdir, | |
917 | .rmdir = hostfs_rmdir, | |
918 | .mknod = hostfs_mknod, | |
919 | .rename = hostfs_rename, | |
1da177e4 LT |
920 | .permission = hostfs_permission, |
921 | .setattr = hostfs_setattr, | |
1da177e4 LT |
922 | }; |
923 | ||
92e1d5be | 924 | static const struct inode_operations hostfs_dir_iops = { |
1da177e4 LT |
925 | .create = hostfs_create, |
926 | .lookup = hostfs_lookup, | |
927 | .link = hostfs_link, | |
928 | .unlink = hostfs_unlink, | |
929 | .symlink = hostfs_symlink, | |
930 | .mkdir = hostfs_mkdir, | |
931 | .rmdir = hostfs_rmdir, | |
932 | .mknod = hostfs_mknod, | |
933 | .rename = hostfs_rename, | |
1da177e4 LT |
934 | .permission = hostfs_permission, |
935 | .setattr = hostfs_setattr, | |
1da177e4 LT |
936 | }; |
937 | ||
938 | int hostfs_link_readpage(struct file *file, struct page *page) | |
939 | { | |
940 | char *buffer, *name; | |
1da177e4 LT |
941 | int err; |
942 | ||
1da177e4 LT |
943 | buffer = kmap(page); |
944 | name = inode_name(page->mapping->host, 0); | |
84b3db04 | 945 | if (name == NULL) |
f1adc05e | 946 | return -ENOMEM; |
ea7e743e | 947 | err = hostfs_do_readlink(name, buffer, PAGE_CACHE_SIZE); |
1da177e4 | 948 | kfree(name); |
84b3db04 | 949 | if (err == PAGE_CACHE_SIZE) |
1da177e4 | 950 | err = -E2BIG; |
84b3db04 | 951 | else if (err > 0) { |
1da177e4 LT |
952 | flush_dcache_page(page); |
953 | SetPageUptodate(page); | |
954 | if (PageError(page)) ClearPageError(page); | |
955 | err = 0; | |
956 | } | |
957 | kunmap(page); | |
958 | unlock_page(page); | |
f1adc05e | 959 | return err; |
1da177e4 LT |
960 | } |
961 | ||
f5e54d6e | 962 | static const struct address_space_operations hostfs_link_aops = { |
1da177e4 LT |
963 | .readpage = hostfs_link_readpage, |
964 | }; | |
965 | ||
966 | static int hostfs_fill_sb_common(struct super_block *sb, void *d, int silent) | |
967 | { | |
968 | struct inode *root_inode; | |
75e8defb | 969 | char *host_root_path, *req_root = d; |
1da177e4 LT |
970 | int err; |
971 | ||
972 | sb->s_blocksize = 1024; | |
973 | sb->s_blocksize_bits = 10; | |
974 | sb->s_magic = HOSTFS_SUPER_MAGIC; | |
975 | sb->s_op = &hostfs_sbops; | |
752fa51e | 976 | sb->s_maxbytes = MAX_LFS_FILESIZE; |
1da177e4 | 977 | |
a6eb0be6 | 978 | /* NULL is printed as <NULL> by sprintf: avoid that. */ |
75e8defb PBG |
979 | if (req_root == NULL) |
980 | req_root = ""; | |
1da177e4 LT |
981 | |
982 | err = -ENOMEM; | |
75e8defb PBG |
983 | host_root_path = kmalloc(strlen(root_ino) + 1 |
984 | + strlen(req_root) + 1, GFP_KERNEL); | |
84b3db04 | 985 | if (host_root_path == NULL) |
1da177e4 LT |
986 | goto out; |
987 | ||
75e8defb | 988 | sprintf(host_root_path, "%s/%s", root_ino, req_root); |
1da177e4 | 989 | |
0a370e5d DH |
990 | root_inode = hostfs_iget(sb); |
991 | if (IS_ERR(root_inode)) { | |
992 | err = PTR_ERR(root_inode); | |
1da177e4 | 993 | goto out_free; |
0a370e5d | 994 | } |
1da177e4 LT |
995 | |
996 | err = init_inode(root_inode, NULL); | |
84b3db04 | 997 | if (err) |
1da177e4 LT |
998 | goto out_put; |
999 | ||
75e8defb | 1000 | HOSTFS_I(root_inode)->host_filename = host_root_path; |
84b3db04 JD |
1001 | /* |
1002 | * Avoid that in the error path, iput(root_inode) frees again | |
1003 | * host_root_path through hostfs_destroy_inode! | |
1004 | */ | |
75e8defb | 1005 | host_root_path = NULL; |
1da177e4 LT |
1006 | |
1007 | err = -ENOMEM; | |
1008 | sb->s_root = d_alloc_root(root_inode); | |
84b3db04 | 1009 | if (sb->s_root == NULL) |
1da177e4 LT |
1010 | goto out_put; |
1011 | ||
0a370e5d | 1012 | err = hostfs_read_inode(root_inode); |
84b3db04 | 1013 | if (err) { |
f1adc05e JD |
1014 | /* No iput in this case because the dput does that for us */ |
1015 | dput(sb->s_root); | |
1016 | sb->s_root = NULL; | |
bca27113 | 1017 | goto out; |
f1adc05e | 1018 | } |
1da177e4 | 1019 | |
f1adc05e | 1020 | return 0; |
1da177e4 | 1021 | |
f1adc05e JD |
1022 | out_put: |
1023 | iput(root_inode); | |
1024 | out_free: | |
75e8defb | 1025 | kfree(host_root_path); |
f1adc05e JD |
1026 | out: |
1027 | return err; | |
1da177e4 LT |
1028 | } |
1029 | ||
454e2398 DH |
1030 | static int hostfs_read_sb(struct file_system_type *type, |
1031 | int flags, const char *dev_name, | |
1032 | void *data, struct vfsmount *mnt) | |
1da177e4 | 1033 | { |
454e2398 | 1034 | return get_sb_nodev(type, flags, data, hostfs_fill_sb_common, mnt); |
1da177e4 LT |
1035 | } |
1036 | ||
1037 | static struct file_system_type hostfs_type = { | |
1038 | .owner = THIS_MODULE, | |
1039 | .name = "hostfs", | |
1040 | .get_sb = hostfs_read_sb, | |
1041 | .kill_sb = kill_anon_super, | |
1042 | .fs_flags = 0, | |
1043 | }; | |
1044 | ||
1045 | static int __init init_hostfs(void) | |
1046 | { | |
f1adc05e | 1047 | return register_filesystem(&hostfs_type); |
1da177e4 LT |
1048 | } |
1049 | ||
1050 | static void __exit exit_hostfs(void) | |
1051 | { | |
1052 | unregister_filesystem(&hostfs_type); | |
1053 | } | |
1054 | ||
1055 | module_init(init_hostfs) | |
1056 | module_exit(exit_hostfs) | |
1057 | MODULE_LICENSE("GPL"); |