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f2fs: fix checkpoint=disable:%u%%
[linux/fpc-iii.git] / fs / hostfs / hostfs_kern.c
blobc070c0d8e3e977b7fbc830bb58ac302abc93f5da
1 /*
2 * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
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
9 #include <linux/fs.h>
10 #include <linux/magic.h>
11 #include <linux/module.h>
12 #include <linux/mm.h>
13 #include <linux/pagemap.h>
14 #include <linux/statfs.h>
15 #include <linux/slab.h>
16 #include <linux/seq_file.h>
17 #include <linux/mount.h>
18 #include <linux/namei.h>
19 #include "hostfs.h"
20 #include <init.h>
21 #include <kern.h>
22
23 struct hostfs_inode_info {
24 int fd;
25 fmode_t mode;
26 struct inode vfs_inode;
27 struct mutex open_mutex;
28 };
29
30 static inline struct hostfs_inode_info *HOSTFS_I(struct inode *inode)
31 {
32 return list_entry(inode, struct hostfs_inode_info, vfs_inode);
33 }
34
35 #define FILE_HOSTFS_I(file) HOSTFS_I(file_inode(file))
36
37 /* Changed in hostfs_args before the kernel starts running */
38 static char *root_ino = "";
39 static int append = 0;
40
41 static const struct inode_operations hostfs_iops;
42 static const struct inode_operations hostfs_dir_iops;
43 static const struct inode_operations hostfs_link_iops;
44
45 #ifndef MODULE
46 static int __init hostfs_args(char *options, int *add)
47 {
48 char *ptr;
49
50 ptr = strchr(options, ',');
51 if (ptr != NULL)
52 *ptr++ = '\0';
53 if (*options != '\0')
54 root_ino = options;
55
56 options = ptr;
57 while (options) {
58 ptr = strchr(options, ',');
59 if (ptr != NULL)
60 *ptr++ = '\0';
61 if (*options != '\0') {
62 if (!strcmp(options, "append"))
63 append = 1;
64 else printf("hostfs_args - unsupported option - %s\n",
65 options);
66 }
67 options = ptr;
68 }
69 return 0;
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
84 static char *__dentry_name(struct dentry *dentry, char *name)
85 {
86 char *p = dentry_path_raw(dentry, name, PATH_MAX);
87 char *root;
88 size_t len;
89
90 root = dentry->d_sb->s_fs_info;
91 len = strlen(root);
92 if (IS_ERR(p)) {
93 __putname(name);
94 return NULL;
95 }
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
103 strlcpy(name, root, PATH_MAX);
104 if (len > p - name) {
105 __putname(name);
106 return NULL;
107 }
108
109 if (p > name + len)
110 strcpy(name + len, p);
111
112 return name;
113 }
114
115 static char *dentry_name(struct dentry *dentry)
116 {
117 char *name = __getname();
118 if (!name)
119 return NULL;
120
121 return __dentry_name(dentry, name);
122 }
123
124 static char *inode_name(struct inode *ino)
125 {
126 struct dentry *dentry;
127 char *name;
128
129 dentry = d_find_alias(ino);
130 if (!dentry)
131 return NULL;
132
133 name = dentry_name(dentry);
134
135 dput(dentry);
136
137 return name;
138 }
139
140 static char *follow_link(char *link)
141 {
142 char *name, *resolved, *end;
143 int n;
144
145 name = __getname();
146 if (!name) {
147 n = -ENOMEM;
148 goto out_free;
149 }
150
151 n = hostfs_do_readlink(link, name, PATH_MAX);
152 if (n < 0)
153 goto out_free;
154 else if (n == PATH_MAX) {
155 n = -E2BIG;
156 goto out_free;
157 }
158
159 if (*name == '/')
160 return name;
161
162 end = strrchr(link, '/');
163 if (end == NULL)
164 return name;
165
166 *(end + 1) = '\0';
167
168 resolved = kasprintf(GFP_KERNEL, "%s%s", link, name);
169 if (resolved == NULL) {
170 n = -ENOMEM;
171 goto out_free;
172 }
173
174 __putname(name);
175 kfree(link);
176 return resolved;
177
178 out_free:
179 __putname(name);
180 return ERR_PTR(n);
181 }
182
183 static struct inode *hostfs_iget(struct super_block *sb)
184 {
185 struct inode *inode = new_inode(sb);
186 if (!inode)
187 return ERR_PTR(-ENOMEM);
188 return inode;
189 }
190
191 static int hostfs_statfs(struct dentry *dentry, struct kstatfs *sf)
192 {
193 /*
194 * do_statfs uses struct statfs64 internally, but the linux kernel
195 * struct statfs still has 32-bit versions for most of these fields,
196 * so we convert them here
197 */
198 int err;
199 long long f_blocks;
200 long long f_bfree;
201 long long f_bavail;
202 long long f_files;
203 long long f_ffree;
204
205 err = do_statfs(dentry->d_sb->s_fs_info,
206 &sf->f_bsize, &f_blocks, &f_bfree, &f_bavail, &f_files,
207 &f_ffree, &sf->f_fsid, sizeof(sf->f_fsid),
208 &sf->f_namelen);
209 if (err)
210 return err;
211 sf->f_blocks = f_blocks;
212 sf->f_bfree = f_bfree;
213 sf->f_bavail = f_bavail;
214 sf->f_files = f_files;
215 sf->f_ffree = f_ffree;
216 sf->f_type = HOSTFS_SUPER_MAGIC;
217 return 0;
218 }
219
220 static struct inode *hostfs_alloc_inode(struct super_block *sb)
221 {
222 struct hostfs_inode_info *hi;
223
224 hi = kmalloc(sizeof(*hi), GFP_KERNEL_ACCOUNT);
225 if (hi == NULL)
226 return NULL;
227 hi->fd = -1;
228 hi->mode = 0;
229 inode_init_once(&hi->vfs_inode);
230 mutex_init(&hi->open_mutex);
231 return &hi->vfs_inode;
232 }
233
234 static void hostfs_evict_inode(struct inode *inode)
235 {
236 truncate_inode_pages_final(&inode->i_data);
237 clear_inode(inode);
238 if (HOSTFS_I(inode)->fd != -1) {
239 close_file(&HOSTFS_I(inode)->fd);
240 HOSTFS_I(inode)->fd = -1;
241 }
242 }
243
244 static void hostfs_free_inode(struct inode *inode)
245 {
246 kfree(HOSTFS_I(inode));
247 }
248
249 static int hostfs_show_options(struct seq_file *seq, struct dentry *root)
250 {
251 const char *root_path = root->d_sb->s_fs_info;
252 size_t offset = strlen(root_ino) + 1;
253
254 if (strlen(root_path) > offset)
255 seq_show_option(seq, root_path + offset, NULL);
256
257 if (append)
258 seq_puts(seq, ",append");
259
260 return 0;
261 }
262
263 static const struct super_operations hostfs_sbops = {
264 .alloc_inode = hostfs_alloc_inode,
265 .free_inode = hostfs_free_inode,
266 .evict_inode = hostfs_evict_inode,
267 .statfs = hostfs_statfs,
268 .show_options = hostfs_show_options,
269 };
270
271 static int hostfs_readdir(struct file *file, struct dir_context *ctx)
272 {
273 void *dir;
274 char *name;
275 unsigned long long next, ino;
276 int error, len;
277 unsigned int type;
278
279 name = dentry_name(file->f_path.dentry);
280 if (name == NULL)
281 return -ENOMEM;
282 dir = open_dir(name, &error);
283 __putname(name);
284 if (dir == NULL)
285 return -error;
286 next = ctx->pos;
287 seek_dir(dir, next);
288 while ((name = read_dir(dir, &next, &ino, &len, &type)) != NULL) {
289 if (!dir_emit(ctx, name, len, ino, type))
290 break;
291 ctx->pos = next;
292 }
293 close_dir(dir);
294 return 0;
295 }
296
297 static int hostfs_open(struct inode *ino, struct file *file)
298 {
299 char *name;
300 fmode_t mode;
301 int err;
302 int r, w, fd;
303
304 mode = file->f_mode & (FMODE_READ | FMODE_WRITE);
305 if ((mode & HOSTFS_I(ino)->mode) == mode)
306 return 0;
307
308 mode |= HOSTFS_I(ino)->mode;
309
310 retry:
311 r = w = 0;
312
313 if (mode & FMODE_READ)
314 r = 1;
315 if (mode & FMODE_WRITE)
316 r = w = 1;
317
318 name = dentry_name(file->f_path.dentry);
319 if (name == NULL)
320 return -ENOMEM;
321
322 fd = open_file(name, r, w, append);
323 __putname(name);
324 if (fd < 0)
325 return fd;
326
327 mutex_lock(&HOSTFS_I(ino)->open_mutex);
328 /* somebody else had handled it first? */
329 if ((mode & HOSTFS_I(ino)->mode) == mode) {
330 mutex_unlock(&HOSTFS_I(ino)->open_mutex);
331 close_file(&fd);
332 return 0;
333 }
334 if ((mode | HOSTFS_I(ino)->mode) != mode) {
335 mode |= HOSTFS_I(ino)->mode;
336 mutex_unlock(&HOSTFS_I(ino)->open_mutex);
337 close_file(&fd);
338 goto retry;
339 }
340 if (HOSTFS_I(ino)->fd == -1) {
341 HOSTFS_I(ino)->fd = fd;
342 } else {
343 err = replace_file(fd, HOSTFS_I(ino)->fd);
344 close_file(&fd);
345 if (err < 0) {
346 mutex_unlock(&HOSTFS_I(ino)->open_mutex);
347 return err;
348 }
349 }
350 HOSTFS_I(ino)->mode = mode;
351 mutex_unlock(&HOSTFS_I(ino)->open_mutex);
352
353 return 0;
354 }
355
356 static int hostfs_file_release(struct inode *inode, struct file *file)
357 {
358 filemap_write_and_wait(inode->i_mapping);
359
360 return 0;
361 }
362
363 static int hostfs_fsync(struct file *file, loff_t start, loff_t end,
364 int datasync)
365 {
366 struct inode *inode = file->f_mapping->host;
367 int ret;
368
369 ret = file_write_and_wait_range(file, start, end);
370 if (ret)
371 return ret;
372
373 inode_lock(inode);
374 ret = fsync_file(HOSTFS_I(inode)->fd, datasync);
375 inode_unlock(inode);
376
377 return ret;
378 }
379
380 static const struct file_operations hostfs_file_fops = {
381 .llseek = generic_file_llseek,
382 .splice_read = generic_file_splice_read,
383 .read_iter = generic_file_read_iter,
384 .write_iter = generic_file_write_iter,
385 .mmap = generic_file_mmap,
386 .open = hostfs_open,
387 .release = hostfs_file_release,
388 .fsync = hostfs_fsync,
389 };
390
391 static const struct file_operations hostfs_dir_fops = {
392 .llseek = generic_file_llseek,
393 .iterate_shared = hostfs_readdir,
394 .read = generic_read_dir,
395 .open = hostfs_open,
396 .fsync = hostfs_fsync,
397 };
398
399 static int hostfs_writepage(struct page *page, struct writeback_control *wbc)
400 {
401 struct address_space *mapping = page->mapping;
402 struct inode *inode = mapping->host;
403 char *buffer;
404 loff_t base = page_offset(page);
405 int count = PAGE_SIZE;
406 int end_index = inode->i_size >> PAGE_SHIFT;
407 int err;
408
409 if (page->index >= end_index)
410 count = inode->i_size & (PAGE_SIZE-1);
411
412 buffer = kmap(page);
413
414 err = write_file(HOSTFS_I(inode)->fd, &base, buffer, count);
415 if (err != count) {
416 ClearPageUptodate(page);
417 goto out;
418 }
419
420 if (base > inode->i_size)
421 inode->i_size = base;
422
423 if (PageError(page))
424 ClearPageError(page);
425 err = 0;
426
427 out:
428 kunmap(page);
429
430 unlock_page(page);
431 return err;
432 }
433
434 static int hostfs_readpage(struct file *file, struct page *page)
435 {
436 char *buffer;
437 loff_t start = page_offset(page);
438 int bytes_read, ret = 0;
439
440 buffer = kmap(page);
441 bytes_read = read_file(FILE_HOSTFS_I(file)->fd, &start, buffer,
442 PAGE_SIZE);
443 if (bytes_read < 0) {
444 ClearPageUptodate(page);
445 SetPageError(page);
446 ret = bytes_read;
447 goto out;
448 }
449
450 memset(buffer + bytes_read, 0, PAGE_SIZE - bytes_read);
451
452 ClearPageError(page);
453 SetPageUptodate(page);
454
455 out:
456 flush_dcache_page(page);
457 kunmap(page);
458 unlock_page(page);
459 return ret;
460 }
461
462 static int hostfs_write_begin(struct file *file, struct address_space *mapping,
463 loff_t pos, unsigned len, unsigned flags,
464 struct page **pagep, void **fsdata)
465 {
466 pgoff_t index = pos >> PAGE_SHIFT;
467
468 *pagep = grab_cache_page_write_begin(mapping, index, flags);
469 if (!*pagep)
470 return -ENOMEM;
471 return 0;
472 }
473
474 static int hostfs_write_end(struct file *file, struct address_space *mapping,
475 loff_t pos, unsigned len, unsigned copied,
476 struct page *page, void *fsdata)
477 {
478 struct inode *inode = mapping->host;
479 void *buffer;
480 unsigned from = pos & (PAGE_SIZE - 1);
481 int err;
482
483 buffer = kmap(page);
484 err = write_file(FILE_HOSTFS_I(file)->fd, &pos, buffer + from, copied);
485 kunmap(page);
486
487 if (!PageUptodate(page) && err == PAGE_SIZE)
488 SetPageUptodate(page);
489
490 /*
491 * If err > 0, write_file has added err to pos, so we are comparing
492 * i_size against the last byte written.
493 */
494 if (err > 0 && (pos > inode->i_size))
495 inode->i_size = pos;
496 unlock_page(page);
497 put_page(page);
498
499 return err;
500 }
501
502 static const struct address_space_operations hostfs_aops = {
503 .writepage = hostfs_writepage,
504 .readpage = hostfs_readpage,
505 .set_page_dirty = __set_page_dirty_nobuffers,
506 .write_begin = hostfs_write_begin,
507 .write_end = hostfs_write_end,
508 };
509
510 static int read_name(struct inode *ino, char *name)
511 {
512 dev_t rdev;
513 struct hostfs_stat st;
514 int err = stat_file(name, &st, -1);
515 if (err)
516 return err;
517
518 /* Reencode maj and min with the kernel encoding.*/
519 rdev = MKDEV(st.maj, st.min);
520
521 switch (st.mode & S_IFMT) {
522 case S_IFLNK:
523 ino->i_op = &hostfs_link_iops;
524 break;
525 case S_IFDIR:
526 ino->i_op = &hostfs_dir_iops;
527 ino->i_fop = &hostfs_dir_fops;
528 break;
529 case S_IFCHR:
530 case S_IFBLK:
531 case S_IFIFO:
532 case S_IFSOCK:
533 init_special_inode(ino, st.mode & S_IFMT, rdev);
534 ino->i_op = &hostfs_iops;
535 break;
536 case S_IFREG:
537 ino->i_op = &hostfs_iops;
538 ino->i_fop = &hostfs_file_fops;
539 ino->i_mapping->a_ops = &hostfs_aops;
540 break;
541 default:
542 return -EIO;
543 }
544
545 ino->i_ino = st.ino;
546 ino->i_mode = st.mode;
547 set_nlink(ino, st.nlink);
548 i_uid_write(ino, st.uid);
549 i_gid_write(ino, st.gid);
550 ino->i_atime = (struct timespec64){ st.atime.tv_sec, st.atime.tv_nsec };
551 ino->i_mtime = (struct timespec64){ st.mtime.tv_sec, st.mtime.tv_nsec };
552 ino->i_ctime = (struct timespec64){ st.ctime.tv_sec, st.ctime.tv_nsec };
553 ino->i_size = st.size;
554 ino->i_blocks = st.blocks;
555 return 0;
556 }
557
558 static int hostfs_create(struct inode *dir, struct dentry *dentry, umode_t mode,
559 bool excl)
560 {
561 struct inode *inode;
562 char *name;
563 int error, fd;
564
565 inode = hostfs_iget(dir->i_sb);
566 if (IS_ERR(inode)) {
567 error = PTR_ERR(inode);
568 goto out;
569 }
570
571 error = -ENOMEM;
572 name = dentry_name(dentry);
573 if (name == NULL)
574 goto out_put;
575
576 fd = file_create(name, mode & 0777);
577 if (fd < 0)
578 error = fd;
579 else
580 error = read_name(inode, name);
581
582 __putname(name);
583 if (error)
584 goto out_put;
585
586 HOSTFS_I(inode)->fd = fd;
587 HOSTFS_I(inode)->mode = FMODE_READ | FMODE_WRITE;
588 d_instantiate(dentry, inode);
589 return 0;
590
591 out_put:
592 iput(inode);
593 out:
594 return error;
595 }
596
597 static struct dentry *hostfs_lookup(struct inode *ino, struct dentry *dentry,
598 unsigned int flags)
599 {
600 struct inode *inode;
601 char *name;
602 int err;
603
604 inode = hostfs_iget(ino->i_sb);
605 if (IS_ERR(inode))
606 goto out;
607
608 err = -ENOMEM;
609 name = dentry_name(dentry);
610 if (name) {
611 err = read_name(inode, name);
612 __putname(name);
613 }
614 if (err) {
615 iput(inode);
616 inode = (err == -ENOENT) ? NULL : ERR_PTR(err);
617 }
618 out:
619 return d_splice_alias(inode, dentry);
620 }
621
622 static int hostfs_link(struct dentry *to, struct inode *ino,
623 struct dentry *from)
624 {
625 char *from_name, *to_name;
626 int err;
627
628 if ((from_name = dentry_name(from)) == NULL)
629 return -ENOMEM;
630 to_name = dentry_name(to);
631 if (to_name == NULL) {
632 __putname(from_name);
633 return -ENOMEM;
634 }
635 err = link_file(to_name, from_name);
636 __putname(from_name);
637 __putname(to_name);
638 return err;
639 }
640
641 static int hostfs_unlink(struct inode *ino, struct dentry *dentry)
642 {
643 char *file;
644 int err;
645
646 if (append)
647 return -EPERM;
648
649 if ((file = dentry_name(dentry)) == NULL)
650 return -ENOMEM;
651
652 err = unlink_file(file);
653 __putname(file);
654 return err;
655 }
656
657 static int hostfs_symlink(struct inode *ino, struct dentry *dentry,
658 const char *to)
659 {
660 char *file;
661 int err;
662
663 if ((file = dentry_name(dentry)) == NULL)
664 return -ENOMEM;
665 err = make_symlink(file, to);
666 __putname(file);
667 return err;
668 }
669
670 static int hostfs_mkdir(struct inode *ino, struct dentry *dentry, umode_t mode)
671 {
672 char *file;
673 int err;
674
675 if ((file = dentry_name(dentry)) == NULL)
676 return -ENOMEM;
677 err = do_mkdir(file, mode);
678 __putname(file);
679 return err;
680 }
681
682 static int hostfs_rmdir(struct inode *ino, struct dentry *dentry)
683 {
684 char *file;
685 int err;
686
687 if ((file = dentry_name(dentry)) == NULL)
688 return -ENOMEM;
689 err = hostfs_do_rmdir(file);
690 __putname(file);
691 return err;
692 }
693
694 static int hostfs_mknod(struct inode *dir, struct dentry *dentry, umode_t mode, dev_t dev)
695 {
696 struct inode *inode;
697 char *name;
698 int err;
699
700 inode = hostfs_iget(dir->i_sb);
701 if (IS_ERR(inode)) {
702 err = PTR_ERR(inode);
703 goto out;
704 }
705
706 err = -ENOMEM;
707 name = dentry_name(dentry);
708 if (name == NULL)
709 goto out_put;
710
711 init_special_inode(inode, mode, dev);
712 err = do_mknod(name, mode, MAJOR(dev), MINOR(dev));
713 if (err)
714 goto out_free;
715
716 err = read_name(inode, name);
717 __putname(name);
718 if (err)
719 goto out_put;
720
721 d_instantiate(dentry, inode);
722 return 0;
723
724 out_free:
725 __putname(name);
726 out_put:
727 iput(inode);
728 out:
729 return err;
730 }
731
732 static int hostfs_rename2(struct inode *old_dir, struct dentry *old_dentry,
733 struct inode *new_dir, struct dentry *new_dentry,
734 unsigned int flags)
735 {
736 char *old_name, *new_name;
737 int err;
738
739 if (flags & ~(RENAME_NOREPLACE | RENAME_EXCHANGE))
740 return -EINVAL;
741
742 old_name = dentry_name(old_dentry);
743 if (old_name == NULL)
744 return -ENOMEM;
745 new_name = dentry_name(new_dentry);
746 if (new_name == NULL) {
747 __putname(old_name);
748 return -ENOMEM;
749 }
750 if (!flags)
751 err = rename_file(old_name, new_name);
752 else
753 err = rename2_file(old_name, new_name, flags);
754
755 __putname(old_name);
756 __putname(new_name);
757 return err;
758 }
759
760 static int hostfs_permission(struct inode *ino, int desired)
761 {
762 char *name;
763 int r = 0, w = 0, x = 0, err;
764
765 if (desired & MAY_NOT_BLOCK)
766 return -ECHILD;
767
768 if (desired & MAY_READ) r = 1;
769 if (desired & MAY_WRITE) w = 1;
770 if (desired & MAY_EXEC) x = 1;
771 name = inode_name(ino);
772 if (name == NULL)
773 return -ENOMEM;
774
775 if (S_ISCHR(ino->i_mode) || S_ISBLK(ino->i_mode) ||
776 S_ISFIFO(ino->i_mode) || S_ISSOCK(ino->i_mode))
777 err = 0;
778 else
779 err = access_file(name, r, w, x);
780 __putname(name);
781 if (!err)
782 err = generic_permission(ino, desired);
783 return err;
784 }
785
786 static int hostfs_setattr(struct dentry *dentry, struct iattr *attr)
787 {
788 struct inode *inode = d_inode(dentry);
789 struct hostfs_iattr attrs;
790 char *name;
791 int err;
792
793 int fd = HOSTFS_I(inode)->fd;
794
795 err = setattr_prepare(dentry, attr);
796 if (err)
797 return err;
798
799 if (append)
800 attr->ia_valid &= ~ATTR_SIZE;
801
802 attrs.ia_valid = 0;
803 if (attr->ia_valid & ATTR_MODE) {
804 attrs.ia_valid |= HOSTFS_ATTR_MODE;
805 attrs.ia_mode = attr->ia_mode;
806 }
807 if (attr->ia_valid & ATTR_UID) {
808 attrs.ia_valid |= HOSTFS_ATTR_UID;
809 attrs.ia_uid = from_kuid(&init_user_ns, attr->ia_uid);
810 }
811 if (attr->ia_valid & ATTR_GID) {
812 attrs.ia_valid |= HOSTFS_ATTR_GID;
813 attrs.ia_gid = from_kgid(&init_user_ns, attr->ia_gid);
814 }
815 if (attr->ia_valid & ATTR_SIZE) {
816 attrs.ia_valid |= HOSTFS_ATTR_SIZE;
817 attrs.ia_size = attr->ia_size;
818 }
819 if (attr->ia_valid & ATTR_ATIME) {
820 attrs.ia_valid |= HOSTFS_ATTR_ATIME;
821 attrs.ia_atime = (struct hostfs_timespec)
822 { attr->ia_atime.tv_sec, attr->ia_atime.tv_nsec };
823 }
824 if (attr->ia_valid & ATTR_MTIME) {
825 attrs.ia_valid |= HOSTFS_ATTR_MTIME;
826 attrs.ia_mtime = (struct hostfs_timespec)
827 { attr->ia_mtime.tv_sec, attr->ia_mtime.tv_nsec };
828 }
829 if (attr->ia_valid & ATTR_CTIME) {
830 attrs.ia_valid |= HOSTFS_ATTR_CTIME;
831 attrs.ia_ctime = (struct hostfs_timespec)
832 { attr->ia_ctime.tv_sec, attr->ia_ctime.tv_nsec };
833 }
834 if (attr->ia_valid & ATTR_ATIME_SET) {
835 attrs.ia_valid |= HOSTFS_ATTR_ATIME_SET;
836 }
837 if (attr->ia_valid & ATTR_MTIME_SET) {
838 attrs.ia_valid |= HOSTFS_ATTR_MTIME_SET;
839 }
840 name = dentry_name(dentry);
841 if (name == NULL)
842 return -ENOMEM;
843 err = set_attr(name, &attrs, fd);
844 __putname(name);
845 if (err)
846 return err;
847
848 if ((attr->ia_valid & ATTR_SIZE) &&
849 attr->ia_size != i_size_read(inode))
850 truncate_setsize(inode, attr->ia_size);
851
852 setattr_copy(inode, attr);
853 mark_inode_dirty(inode);
854 return 0;
855 }
856
857 static const struct inode_operations hostfs_iops = {
858 .permission = hostfs_permission,
859 .setattr = hostfs_setattr,
860 };
861
862 static const struct inode_operations hostfs_dir_iops = {
863 .create = hostfs_create,
864 .lookup = hostfs_lookup,
865 .link = hostfs_link,
866 .unlink = hostfs_unlink,
867 .symlink = hostfs_symlink,
868 .mkdir = hostfs_mkdir,
869 .rmdir = hostfs_rmdir,
870 .mknod = hostfs_mknod,
871 .rename = hostfs_rename2,
872 .permission = hostfs_permission,
873 .setattr = hostfs_setattr,
874 };
875
876 static const char *hostfs_get_link(struct dentry *dentry,
877 struct inode *inode,
878 struct delayed_call *done)
879 {
880 char *link;
881 if (!dentry)
882 return ERR_PTR(-ECHILD);
883 link = kmalloc(PATH_MAX, GFP_KERNEL);
884 if (link) {
885 char *path = dentry_name(dentry);
886 int err = -ENOMEM;
887 if (path) {
888 err = hostfs_do_readlink(path, link, PATH_MAX);
889 if (err == PATH_MAX)
890 err = -E2BIG;
891 __putname(path);
892 }
893 if (err < 0) {
894 kfree(link);
895 return ERR_PTR(err);
896 }
897 } else {
898 return ERR_PTR(-ENOMEM);
899 }
900
901 set_delayed_call(done, kfree_link, link);
902 return link;
903 }
904
905 static const struct inode_operations hostfs_link_iops = {
906 .get_link = hostfs_get_link,
907 };
908
909 static int hostfs_fill_sb_common(struct super_block *sb, void *d, int silent)
910 {
911 struct inode *root_inode;
912 char *host_root_path, *req_root = d;
913 int err;
914
915 sb->s_blocksize = 1024;
916 sb->s_blocksize_bits = 10;
917 sb->s_magic = HOSTFS_SUPER_MAGIC;
918 sb->s_op = &hostfs_sbops;
919 sb->s_d_op = &simple_dentry_operations;
920 sb->s_maxbytes = MAX_LFS_FILESIZE;
921
922 /* NULL is printed as '(null)' by printf(): avoid that. */
923 if (req_root == NULL)
924 req_root = "";
925
926 err = -ENOMEM;
927 sb->s_fs_info = host_root_path =
928 kasprintf(GFP_KERNEL, "%s/%s", root_ino, req_root);
929 if (host_root_path == NULL)
930 goto out;
931
932 root_inode = new_inode(sb);
933 if (!root_inode)
934 goto out;
935
936 err = read_name(root_inode, host_root_path);
937 if (err)
938 goto out_put;
939
940 if (S_ISLNK(root_inode->i_mode)) {
941 char *name = follow_link(host_root_path);
942 if (IS_ERR(name)) {
943 err = PTR_ERR(name);
944 goto out_put;
945 }
946 err = read_name(root_inode, name);
947 kfree(name);
948 if (err)
949 goto out_put;
950 }
951
952 err = -ENOMEM;
953 sb->s_root = d_make_root(root_inode);
954 if (sb->s_root == NULL)
955 goto out;
956
957 return 0;
958
959 out_put:
960 iput(root_inode);
961 out:
962 return err;
963 }
964
965 static struct dentry *hostfs_read_sb(struct file_system_type *type,
966 int flags, const char *dev_name,
967 void *data)
968 {
969 return mount_nodev(type, flags, data, hostfs_fill_sb_common);
970 }
971
972 static void hostfs_kill_sb(struct super_block *s)
973 {
974 kill_anon_super(s);
975 kfree(s->s_fs_info);
976 }
977
978 static struct file_system_type hostfs_type = {
979 .owner = THIS_MODULE,
980 .name = "hostfs",
981 .mount = hostfs_read_sb,
982 .kill_sb = hostfs_kill_sb,
983 .fs_flags = 0,
984 };
985 MODULE_ALIAS_FS("hostfs");
986
987 static int __init init_hostfs(void)
988 {
989 return register_filesystem(&hostfs_type);
990 }
991
992 static void __exit exit_hostfs(void)
993 {
994 unregister_filesystem(&hostfs_type);
995 }
996
997 module_init(init_hostfs)
998 module_exit(exit_hostfs)
999 MODULE_LICENSE("GPL");
Linux with added FPC-III support