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Merge branch 'master'
[deliverable/linux.git] / fs / hostfs / hostfs_kern.c
1 /*
2 * Copyright (C) 2000, 2001, 2002 Jeff Dike (jdike@karaya.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/stddef.h>
10 #include <linux/fs.h>
11 #include <linux/module.h>
12 #include <linux/init.h>
13 #include <linux/slab.h>
14 #include <linux/pagemap.h>
15 #include <linux/blkdev.h>
16 #include <linux/list.h>
17 #include <linux/statfs.h>
18 #include <linux/kdev_t.h>
19 #include <asm/uaccess.h>
20 #include "hostfs.h"
21 #include "kern_util.h"
22 #include "kern.h"
23 #include "user_util.h"
24 #include "init.h"
25
26 struct hostfs_inode_info {
27 char *host_filename;
28 int fd;
29 int mode;
30 struct inode vfs_inode;
31 };
32
33 static inline struct hostfs_inode_info *HOSTFS_I(struct inode *inode)
34 {
35 return(list_entry(inode, struct hostfs_inode_info, vfs_inode));
36 }
37
38 #define FILE_HOSTFS_I(file) HOSTFS_I((file)->f_dentry->d_inode)
39
40 int hostfs_d_delete(struct dentry *dentry)
41 {
42 return(1);
43 }
44
45 struct dentry_operations hostfs_dentry_ops = {
46 .d_delete = hostfs_d_delete,
47 };
48
49 /* Changed in hostfs_args before the kernel starts running */
50 static char *root_ino = "/";
51 static int append = 0;
52
53 #define HOSTFS_SUPER_MAGIC 0x00c0ffee
54
55 static struct inode_operations hostfs_iops;
56 static struct inode_operations hostfs_dir_iops;
57 static struct address_space_operations hostfs_link_aops;
58
59 #ifndef MODULE
60 static int __init hostfs_args(char *options, int *add)
61 {
62 char *ptr;
63
64 ptr = strchr(options, ',');
65 if(ptr != NULL)
66 *ptr++ = '\0';
67 if(*options != '\0')
68 root_ino = options;
69
70 options = ptr;
71 while(options){
72 ptr = strchr(options, ',');
73 if(ptr != NULL)
74 *ptr++ = '\0';
75 if(*options != '\0'){
76 if(!strcmp(options, "append"))
77 append = 1;
78 else printf("hostfs_args - unsupported option - %s\n",
79 options);
80 }
81 options = ptr;
82 }
83 return(0);
84 }
85
86 __uml_setup("hostfs=", hostfs_args,
87 "hostfs=<root dir>,<flags>,...\n"
88 " This is used to set hostfs parameters. The root directory argument\n"
89 " is used to confine all hostfs mounts to within the specified directory\n"
90 " tree on the host. If this isn't specified, then a user inside UML can\n"
91 " mount anything on the host that's accessible to the user that's running\n"
92 " it.\n"
93 " The only flag currently supported is 'append', which specifies that all\n"
94 " files opened by hostfs will be opened in append mode.\n\n"
95 );
96 #endif
97
98 static char *dentry_name(struct dentry *dentry, int extra)
99 {
100 struct dentry *parent;
101 char *root, *name;
102 int len;
103
104 len = 0;
105 parent = dentry;
106 while(parent->d_parent != parent){
107 len += parent->d_name.len + 1;
108 parent = parent->d_parent;
109 }
110
111 root = HOSTFS_I(parent->d_inode)->host_filename;
112 len += strlen(root);
113 name = kmalloc(len + extra + 1, GFP_KERNEL);
114 if(name == NULL) return(NULL);
115
116 name[len] = '\0';
117 parent = dentry;
118 while(parent->d_parent != parent){
119 len -= parent->d_name.len + 1;
120 name[len] = '/';
121 strncpy(&name[len + 1], parent->d_name.name,
122 parent->d_name.len);
123 parent = parent->d_parent;
124 }
125 strncpy(name, root, strlen(root));
126 return(name);
127 }
128
129 static char *inode_name(struct inode *ino, int extra)
130 {
131 struct dentry *dentry;
132
133 dentry = list_entry(ino->i_dentry.next, struct dentry, d_alias);
134 return(dentry_name(dentry, extra));
135 }
136
137 static int read_name(struct inode *ino, char *name)
138 {
139 /* The non-int inode fields are copied into ints by stat_file and
140 * then copied into the inode because passing the actual pointers
141 * in and having them treated as int * breaks on big-endian machines
142 */
143 int err;
144 int i_mode, i_nlink, i_blksize;
145 unsigned long long i_size;
146 unsigned long long i_ino;
147 unsigned long long i_blocks;
148
149 err = stat_file(name, &i_ino, &i_mode, &i_nlink, &ino->i_uid,
150 &ino->i_gid, &i_size, &ino->i_atime, &ino->i_mtime,
151 &ino->i_ctime, &i_blksize, &i_blocks);
152 if(err)
153 return(err);
154
155 ino->i_ino = i_ino;
156 ino->i_mode = i_mode;
157 ino->i_nlink = i_nlink;
158 ino->i_size = i_size;
159 ino->i_blksize = i_blksize;
160 ino->i_blocks = i_blocks;
161 return(0);
162 }
163
164 static char *follow_link(char *link)
165 {
166 int len, n;
167 char *name, *resolved, *end;
168
169 len = 64;
170 while(1){
171 n = -ENOMEM;
172 name = kmalloc(len, GFP_KERNEL);
173 if(name == NULL)
174 goto out;
175
176 n = do_readlink(link, name, len);
177 if(n < len)
178 break;
179 len *= 2;
180 kfree(name);
181 }
182 if(n < 0)
183 goto out_free;
184
185 if(*name == '/')
186 return(name);
187
188 end = strrchr(link, '/');
189 if(end == NULL)
190 return(name);
191
192 *(end + 1) = '\0';
193 len = strlen(link) + strlen(name) + 1;
194
195 resolved = kmalloc(len, GFP_KERNEL);
196 if(resolved == NULL){
197 n = -ENOMEM;
198 goto out_free;
199 }
200
201 sprintf(resolved, "%s%s", link, name);
202 kfree(name);
203 kfree(link);
204 return(resolved);
205
206 out_free:
207 kfree(name);
208 out:
209 return(ERR_PTR(n));
210 }
211
212 static int read_inode(struct inode *ino)
213 {
214 char *name;
215 int err = 0;
216
217 /* Unfortunately, we are called from iget() when we don't have a dentry
218 * allocated yet.
219 */
220 if(list_empty(&ino->i_dentry))
221 goto out;
222
223 err = -ENOMEM;
224 name = inode_name(ino, 0);
225 if(name == NULL)
226 goto out;
227
228 if(file_type(name, NULL, NULL) == OS_TYPE_SYMLINK){
229 name = follow_link(name);
230 if(IS_ERR(name)){
231 err = PTR_ERR(name);
232 goto out;
233 }
234 }
235
236 err = read_name(ino, name);
237 kfree(name);
238 out:
239 return(err);
240 }
241
242 int hostfs_statfs(struct super_block *sb, struct kstatfs *sf)
243 {
244 /* do_statfs uses struct statfs64 internally, but the linux kernel
245 * struct statfs still has 32-bit versions for most of these fields,
246 * so we convert them here
247 */
248 int err;
249 long long f_blocks;
250 long long f_bfree;
251 long long f_bavail;
252 long long f_files;
253 long long f_ffree;
254
255 err = do_statfs(HOSTFS_I(sb->s_root->d_inode)->host_filename,
256 &sf->f_bsize, &f_blocks, &f_bfree, &f_bavail, &f_files,
257 &f_ffree, &sf->f_fsid, sizeof(sf->f_fsid),
258 &sf->f_namelen, sf->f_spare);
259 if(err) return(err);
260 sf->f_blocks = f_blocks;
261 sf->f_bfree = f_bfree;
262 sf->f_bavail = f_bavail;
263 sf->f_files = f_files;
264 sf->f_ffree = f_ffree;
265 sf->f_type = HOSTFS_SUPER_MAGIC;
266 return(0);
267 }
268
269 static struct inode *hostfs_alloc_inode(struct super_block *sb)
270 {
271 struct hostfs_inode_info *hi;
272
273 hi = kmalloc(sizeof(*hi), GFP_KERNEL);
274 if(hi == NULL)
275 return(NULL);
276
277 *hi = ((struct hostfs_inode_info) { .host_filename = NULL,
278 .fd = -1,
279 .mode = 0 });
280 inode_init_once(&hi->vfs_inode);
281 return(&hi->vfs_inode);
282 }
283
284 static void hostfs_delete_inode(struct inode *inode)
285 {
286 truncate_inode_pages(&inode->i_data, 0);
287 if(HOSTFS_I(inode)->fd != -1) {
288 close_file(&HOSTFS_I(inode)->fd);
289 HOSTFS_I(inode)->fd = -1;
290 }
291 clear_inode(inode);
292 }
293
294 static void hostfs_destroy_inode(struct inode *inode)
295 {
296 kfree(HOSTFS_I(inode)->host_filename);
297
298 /*XXX: This should not happen, probably. The check is here for
299 * additional safety.*/
300 if(HOSTFS_I(inode)->fd != -1) {
301 close_file(&HOSTFS_I(inode)->fd);
302 printk(KERN_DEBUG "Closing host fd in .destroy_inode\n");
303 }
304
305 kfree(HOSTFS_I(inode));
306 }
307
308 static void hostfs_read_inode(struct inode *inode)
309 {
310 read_inode(inode);
311 }
312
313 static struct super_operations hostfs_sbops = {
314 .alloc_inode = hostfs_alloc_inode,
315 .drop_inode = generic_delete_inode,
316 .delete_inode = hostfs_delete_inode,
317 .destroy_inode = hostfs_destroy_inode,
318 .read_inode = hostfs_read_inode,
319 .statfs = hostfs_statfs,
320 };
321
322 int hostfs_readdir(struct file *file, void *ent, filldir_t filldir)
323 {
324 void *dir;
325 char *name;
326 unsigned long long next, ino;
327 int error, len;
328
329 name = dentry_name(file->f_dentry, 0);
330 if(name == NULL) return(-ENOMEM);
331 dir = open_dir(name, &error);
332 kfree(name);
333 if(dir == NULL) return(-error);
334 next = file->f_pos;
335 while((name = read_dir(dir, &next, &ino, &len)) != NULL){
336 error = (*filldir)(ent, name, len, file->f_pos,
337 ino, DT_UNKNOWN);
338 if(error) break;
339 file->f_pos = next;
340 }
341 close_dir(dir);
342 return(0);
343 }
344
345 int hostfs_file_open(struct inode *ino, struct file *file)
346 {
347 char *name;
348 int mode = 0, r = 0, w = 0, fd;
349
350 mode = file->f_mode & (FMODE_READ | FMODE_WRITE);
351 if((mode & HOSTFS_I(ino)->mode) == mode)
352 return(0);
353
354 /* The file may already have been opened, but with the wrong access,
355 * so this resets things and reopens the file with the new access.
356 */
357 if(HOSTFS_I(ino)->fd != -1){
358 close_file(&HOSTFS_I(ino)->fd);
359 HOSTFS_I(ino)->fd = -1;
360 }
361
362 HOSTFS_I(ino)->mode |= mode;
363 if(HOSTFS_I(ino)->mode & FMODE_READ)
364 r = 1;
365 if(HOSTFS_I(ino)->mode & FMODE_WRITE)
366 w = 1;
367 if(w)
368 r = 1;
369
370 name = dentry_name(file->f_dentry, 0);
371 if(name == NULL)
372 return(-ENOMEM);
373
374 fd = open_file(name, r, w, append);
375 kfree(name);
376 if(fd < 0) return(fd);
377 FILE_HOSTFS_I(file)->fd = fd;
378
379 return(0);
380 }
381
382 int hostfs_fsync(struct file *file, struct dentry *dentry, int datasync)
383 {
384 return fsync_file(HOSTFS_I(dentry->d_inode)->fd, datasync);
385 }
386
387 static struct file_operations hostfs_file_fops = {
388 .llseek = generic_file_llseek,
389 .read = generic_file_read,
390 .sendfile = generic_file_sendfile,
391 .aio_read = generic_file_aio_read,
392 .aio_write = generic_file_aio_write,
393 .readv = generic_file_readv,
394 .writev = generic_file_writev,
395 .write = generic_file_write,
396 .mmap = generic_file_mmap,
397 .open = hostfs_file_open,
398 .release = NULL,
399 .fsync = hostfs_fsync,
400 };
401
402 static struct file_operations hostfs_dir_fops = {
403 .llseek = generic_file_llseek,
404 .readdir = hostfs_readdir,
405 .read = generic_read_dir,
406 };
407
408 int hostfs_writepage(struct page *page, struct writeback_control *wbc)
409 {
410 struct address_space *mapping = page->mapping;
411 struct inode *inode = mapping->host;
412 char *buffer;
413 unsigned long long base;
414 int count = PAGE_CACHE_SIZE;
415 int end_index = inode->i_size >> PAGE_CACHE_SHIFT;
416 int err;
417
418 if (page->index >= end_index)
419 count = inode->i_size & (PAGE_CACHE_SIZE-1);
420
421 buffer = kmap(page);
422 base = ((unsigned long long) page->index) << PAGE_CACHE_SHIFT;
423
424 err = write_file(HOSTFS_I(inode)->fd, &base, buffer, count);
425 if(err != count){
426 ClearPageUptodate(page);
427 goto out;
428 }
429
430 if (base > inode->i_size)
431 inode->i_size = base;
432
433 if (PageError(page))
434 ClearPageError(page);
435 err = 0;
436
437 out:
438 kunmap(page);
439
440 unlock_page(page);
441 return err;
442 }
443
444 int hostfs_readpage(struct file *file, struct page *page)
445 {
446 char *buffer;
447 long long start;
448 int err = 0;
449
450 start = (long long) page->index << PAGE_CACHE_SHIFT;
451 buffer = kmap(page);
452 err = read_file(FILE_HOSTFS_I(file)->fd, &start, buffer,
453 PAGE_CACHE_SIZE);
454 if(err < 0) goto out;
455
456 memset(&buffer[err], 0, PAGE_CACHE_SIZE - err);
457
458 flush_dcache_page(page);
459 SetPageUptodate(page);
460 if (PageError(page)) ClearPageError(page);
461 err = 0;
462 out:
463 kunmap(page);
464 unlock_page(page);
465 return(err);
466 }
467
468 int hostfs_prepare_write(struct file *file, struct page *page,
469 unsigned int from, unsigned int to)
470 {
471 char *buffer;
472 long long start, tmp;
473 int err;
474
475 start = (long long) page->index << PAGE_CACHE_SHIFT;
476 buffer = kmap(page);
477 if(from != 0){
478 tmp = start;
479 err = read_file(FILE_HOSTFS_I(file)->fd, &tmp, buffer,
480 from);
481 if(err < 0) goto out;
482 }
483 if(to != PAGE_CACHE_SIZE){
484 start += to;
485 err = read_file(FILE_HOSTFS_I(file)->fd, &start, buffer + to,
486 PAGE_CACHE_SIZE - to);
487 if(err < 0) goto out;
488 }
489 err = 0;
490 out:
491 kunmap(page);
492 return(err);
493 }
494
495 int hostfs_commit_write(struct file *file, struct page *page, unsigned from,
496 unsigned to)
497 {
498 struct address_space *mapping = page->mapping;
499 struct inode *inode = mapping->host;
500 char *buffer;
501 long long start;
502 int err = 0;
503
504 start = (long long) (page->index << PAGE_CACHE_SHIFT) + from;
505 buffer = kmap(page);
506 err = write_file(FILE_HOSTFS_I(file)->fd, &start, buffer + from,
507 to - from);
508 if(err > 0) err = 0;
509 if(!err && (start > inode->i_size))
510 inode->i_size = start;
511
512 kunmap(page);
513 return(err);
514 }
515
516 static struct address_space_operations hostfs_aops = {
517 .writepage = hostfs_writepage,
518 .readpage = hostfs_readpage,
519 .set_page_dirty = __set_page_dirty_nobuffers,
520 .prepare_write = hostfs_prepare_write,
521 .commit_write = hostfs_commit_write
522 };
523
524 static int init_inode(struct inode *inode, struct dentry *dentry)
525 {
526 char *name;
527 int type, err = -ENOMEM;
528 int maj, min;
529 dev_t rdev = 0;
530
531 if(dentry){
532 name = dentry_name(dentry, 0);
533 if(name == NULL)
534 goto out;
535 type = file_type(name, &maj, &min);
536 /*Reencode maj and min with the kernel encoding.*/
537 rdev = MKDEV(maj, min);
538 kfree(name);
539 }
540 else type = OS_TYPE_DIR;
541
542 err = 0;
543 if(type == OS_TYPE_SYMLINK)
544 inode->i_op = &page_symlink_inode_operations;
545 else if(type == OS_TYPE_DIR)
546 inode->i_op = &hostfs_dir_iops;
547 else inode->i_op = &hostfs_iops;
548
549 if(type == OS_TYPE_DIR) inode->i_fop = &hostfs_dir_fops;
550 else inode->i_fop = &hostfs_file_fops;
551
552 if(type == OS_TYPE_SYMLINK)
553 inode->i_mapping->a_ops = &hostfs_link_aops;
554 else inode->i_mapping->a_ops = &hostfs_aops;
555
556 switch (type) {
557 case OS_TYPE_CHARDEV:
558 init_special_inode(inode, S_IFCHR, rdev);
559 break;
560 case OS_TYPE_BLOCKDEV:
561 init_special_inode(inode, S_IFBLK, rdev);
562 break;
563 case OS_TYPE_FIFO:
564 init_special_inode(inode, S_IFIFO, 0);
565 break;
566 case OS_TYPE_SOCK:
567 init_special_inode(inode, S_IFSOCK, 0);
568 break;
569 }
570 out:
571 return(err);
572 }
573
574 int hostfs_create(struct inode *dir, struct dentry *dentry, int mode,
575 struct nameidata *nd)
576 {
577 struct inode *inode;
578 char *name;
579 int error, fd;
580
581 error = -ENOMEM;
582 inode = iget(dir->i_sb, 0);
583 if(inode == NULL) goto out;
584
585 error = init_inode(inode, dentry);
586 if(error)
587 goto out_put;
588
589 error = -ENOMEM;
590 name = dentry_name(dentry, 0);
591 if(name == NULL)
592 goto out_put;
593
594 fd = file_create(name,
595 mode & S_IRUSR, mode & S_IWUSR, mode & S_IXUSR,
596 mode & S_IRGRP, mode & S_IWGRP, mode & S_IXGRP,
597 mode & S_IROTH, mode & S_IWOTH, mode & S_IXOTH);
598 if(fd < 0)
599 error = fd;
600 else error = read_name(inode, name);
601
602 kfree(name);
603 if(error)
604 goto out_put;
605
606 HOSTFS_I(inode)->fd = fd;
607 HOSTFS_I(inode)->mode = FMODE_READ | FMODE_WRITE;
608 d_instantiate(dentry, inode);
609 return(0);
610
611 out_put:
612 iput(inode);
613 out:
614 return(error);
615 }
616
617 struct dentry *hostfs_lookup(struct inode *ino, struct dentry *dentry,
618 struct nameidata *nd)
619 {
620 struct inode *inode;
621 char *name;
622 int err;
623
624 err = -ENOMEM;
625 inode = iget(ino->i_sb, 0);
626 if(inode == NULL)
627 goto out;
628
629 err = init_inode(inode, dentry);
630 if(err)
631 goto out_put;
632
633 err = -ENOMEM;
634 name = dentry_name(dentry, 0);
635 if(name == NULL)
636 goto out_put;
637
638 err = read_name(inode, name);
639 kfree(name);
640 if(err == -ENOENT){
641 iput(inode);
642 inode = NULL;
643 }
644 else if(err)
645 goto out_put;
646
647 d_add(dentry, inode);
648 dentry->d_op = &hostfs_dentry_ops;
649 return(NULL);
650
651 out_put:
652 iput(inode);
653 out:
654 return(ERR_PTR(err));
655 }
656
657 static char *inode_dentry_name(struct inode *ino, struct dentry *dentry)
658 {
659 char *file;
660 int len;
661
662 file = inode_name(ino, dentry->d_name.len + 1);
663 if(file == NULL) return(NULL);
664 strcat(file, "/");
665 len = strlen(file);
666 strncat(file, dentry->d_name.name, dentry->d_name.len);
667 file[len + dentry->d_name.len] = '\0';
668 return(file);
669 }
670
671 int hostfs_link(struct dentry *to, struct inode *ino, struct dentry *from)
672 {
673 char *from_name, *to_name;
674 int err;
675
676 if((from_name = inode_dentry_name(ino, from)) == NULL)
677 return(-ENOMEM);
678 to_name = dentry_name(to, 0);
679 if(to_name == NULL){
680 kfree(from_name);
681 return(-ENOMEM);
682 }
683 err = link_file(to_name, from_name);
684 kfree(from_name);
685 kfree(to_name);
686 return(err);
687 }
688
689 int hostfs_unlink(struct inode *ino, struct dentry *dentry)
690 {
691 char *file;
692 int err;
693
694 if((file = inode_dentry_name(ino, dentry)) == NULL) return(-ENOMEM);
695 if(append)
696 return(-EPERM);
697
698 err = unlink_file(file);
699 kfree(file);
700 return(err);
701 }
702
703 int hostfs_symlink(struct inode *ino, struct dentry *dentry, const char *to)
704 {
705 char *file;
706 int err;
707
708 if((file = inode_dentry_name(ino, dentry)) == NULL) return(-ENOMEM);
709 err = make_symlink(file, to);
710 kfree(file);
711 return(err);
712 }
713
714 int hostfs_mkdir(struct inode *ino, struct dentry *dentry, int mode)
715 {
716 char *file;
717 int err;
718
719 if((file = inode_dentry_name(ino, dentry)) == NULL) return(-ENOMEM);
720 err = do_mkdir(file, mode);
721 kfree(file);
722 return(err);
723 }
724
725 int hostfs_rmdir(struct inode *ino, struct dentry *dentry)
726 {
727 char *file;
728 int err;
729
730 if((file = inode_dentry_name(ino, dentry)) == NULL) return(-ENOMEM);
731 err = do_rmdir(file);
732 kfree(file);
733 return(err);
734 }
735
736 int hostfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev)
737 {
738 struct inode *inode;
739 char *name;
740 int err = -ENOMEM;
741
742 inode = iget(dir->i_sb, 0);
743 if(inode == NULL)
744 goto out;
745
746 err = init_inode(inode, dentry);
747 if(err)
748 goto out_put;
749
750 err = -ENOMEM;
751 name = dentry_name(dentry, 0);
752 if(name == NULL)
753 goto out_put;
754
755 init_special_inode(inode, mode, dev);
756 err = do_mknod(name, mode, dev);
757 if(err)
758 goto out_free;
759
760 err = read_name(inode, name);
761 kfree(name);
762 if(err)
763 goto out_put;
764
765 d_instantiate(dentry, inode);
766 return(0);
767
768 out_free:
769 kfree(name);
770 out_put:
771 iput(inode);
772 out:
773 return(err);
774 }
775
776 int hostfs_rename(struct inode *from_ino, struct dentry *from,
777 struct inode *to_ino, struct dentry *to)
778 {
779 char *from_name, *to_name;
780 int err;
781
782 if((from_name = inode_dentry_name(from_ino, from)) == NULL)
783 return(-ENOMEM);
784 if((to_name = inode_dentry_name(to_ino, to)) == NULL){
785 kfree(from_name);
786 return(-ENOMEM);
787 }
788 err = rename_file(from_name, to_name);
789 kfree(from_name);
790 kfree(to_name);
791 return(err);
792 }
793
794 int hostfs_permission(struct inode *ino, int desired, struct nameidata *nd)
795 {
796 char *name;
797 int r = 0, w = 0, x = 0, err;
798
799 if (desired & MAY_READ) r = 1;
800 if (desired & MAY_WRITE) w = 1;
801 if (desired & MAY_EXEC) x = 1;
802 name = inode_name(ino, 0);
803 if (name == NULL) return(-ENOMEM);
804
805 if (S_ISCHR(ino->i_mode) || S_ISBLK(ino->i_mode) ||
806 S_ISFIFO(ino->i_mode) || S_ISSOCK(ino->i_mode))
807 err = 0;
808 else
809 err = access_file(name, r, w, x);
810 kfree(name);
811 if(!err)
812 err = generic_permission(ino, desired, NULL);
813 return err;
814 }
815
816 int hostfs_setattr(struct dentry *dentry, struct iattr *attr)
817 {
818 struct hostfs_iattr attrs;
819 char *name;
820 int err;
821
822 err = inode_change_ok(dentry->d_inode, attr);
823 if (err)
824 return err;
825
826 if(append)
827 attr->ia_valid &= ~ATTR_SIZE;
828
829 attrs.ia_valid = 0;
830 if(attr->ia_valid & ATTR_MODE){
831 attrs.ia_valid |= HOSTFS_ATTR_MODE;
832 attrs.ia_mode = attr->ia_mode;
833 }
834 if(attr->ia_valid & ATTR_UID){
835 attrs.ia_valid |= HOSTFS_ATTR_UID;
836 attrs.ia_uid = attr->ia_uid;
837 }
838 if(attr->ia_valid & ATTR_GID){
839 attrs.ia_valid |= HOSTFS_ATTR_GID;
840 attrs.ia_gid = attr->ia_gid;
841 }
842 if(attr->ia_valid & ATTR_SIZE){
843 attrs.ia_valid |= HOSTFS_ATTR_SIZE;
844 attrs.ia_size = attr->ia_size;
845 }
846 if(attr->ia_valid & ATTR_ATIME){
847 attrs.ia_valid |= HOSTFS_ATTR_ATIME;
848 attrs.ia_atime = attr->ia_atime;
849 }
850 if(attr->ia_valid & ATTR_MTIME){
851 attrs.ia_valid |= HOSTFS_ATTR_MTIME;
852 attrs.ia_mtime = attr->ia_mtime;
853 }
854 if(attr->ia_valid & ATTR_CTIME){
855 attrs.ia_valid |= HOSTFS_ATTR_CTIME;
856 attrs.ia_ctime = attr->ia_ctime;
857 }
858 if(attr->ia_valid & ATTR_ATIME_SET){
859 attrs.ia_valid |= HOSTFS_ATTR_ATIME_SET;
860 }
861 if(attr->ia_valid & ATTR_MTIME_SET){
862 attrs.ia_valid |= HOSTFS_ATTR_MTIME_SET;
863 }
864 name = dentry_name(dentry, 0);
865 if(name == NULL) return(-ENOMEM);
866 err = set_attr(name, &attrs);
867 kfree(name);
868 if(err)
869 return(err);
870
871 return(inode_setattr(dentry->d_inode, attr));
872 }
873
874 int hostfs_getattr(struct vfsmount *mnt, struct dentry *dentry,
875 struct kstat *stat)
876 {
877 generic_fillattr(dentry->d_inode, stat);
878 return(0);
879 }
880
881 static struct inode_operations hostfs_iops = {
882 .create = hostfs_create,
883 .link = hostfs_link,
884 .unlink = hostfs_unlink,
885 .symlink = hostfs_symlink,
886 .mkdir = hostfs_mkdir,
887 .rmdir = hostfs_rmdir,
888 .mknod = hostfs_mknod,
889 .rename = hostfs_rename,
890 .permission = hostfs_permission,
891 .setattr = hostfs_setattr,
892 .getattr = hostfs_getattr,
893 };
894
895 static struct inode_operations hostfs_dir_iops = {
896 .create = hostfs_create,
897 .lookup = hostfs_lookup,
898 .link = hostfs_link,
899 .unlink = hostfs_unlink,
900 .symlink = hostfs_symlink,
901 .mkdir = hostfs_mkdir,
902 .rmdir = hostfs_rmdir,
903 .mknod = hostfs_mknod,
904 .rename = hostfs_rename,
905 .permission = hostfs_permission,
906 .setattr = hostfs_setattr,
907 .getattr = hostfs_getattr,
908 };
909
910 int hostfs_link_readpage(struct file *file, struct page *page)
911 {
912 char *buffer, *name;
913 long long start;
914 int err;
915
916 start = page->index << PAGE_CACHE_SHIFT;
917 buffer = kmap(page);
918 name = inode_name(page->mapping->host, 0);
919 if(name == NULL) return(-ENOMEM);
920 err = do_readlink(name, buffer, PAGE_CACHE_SIZE);
921 kfree(name);
922 if(err == PAGE_CACHE_SIZE)
923 err = -E2BIG;
924 else if(err > 0){
925 flush_dcache_page(page);
926 SetPageUptodate(page);
927 if (PageError(page)) ClearPageError(page);
928 err = 0;
929 }
930 kunmap(page);
931 unlock_page(page);
932 return(err);
933 }
934
935 static struct address_space_operations hostfs_link_aops = {
936 .readpage = hostfs_link_readpage,
937 };
938
939 static int hostfs_fill_sb_common(struct super_block *sb, void *d, int silent)
940 {
941 struct inode *root_inode;
942 char *name, *data = d;
943 int err;
944
945 sb->s_blocksize = 1024;
946 sb->s_blocksize_bits = 10;
947 sb->s_magic = HOSTFS_SUPER_MAGIC;
948 sb->s_op = &hostfs_sbops;
949
950 if((data == NULL) || (*data == '\0'))
951 data = root_ino;
952
953 err = -ENOMEM;
954 name = kmalloc(strlen(data) + 1, GFP_KERNEL);
955 if(name == NULL)
956 goto out;
957
958 strcpy(name, data);
959
960 root_inode = iget(sb, 0);
961 if(root_inode == NULL)
962 goto out_free;
963
964 err = init_inode(root_inode, NULL);
965 if(err)
966 goto out_put;
967
968 HOSTFS_I(root_inode)->host_filename = name;
969
970 err = -ENOMEM;
971 sb->s_root = d_alloc_root(root_inode);
972 if(sb->s_root == NULL)
973 goto out_put;
974
975 err = read_inode(root_inode);
976 if(err){
977 /* No iput in this case because the dput does that for us */
978 dput(sb->s_root);
979 sb->s_root = NULL;
980 goto out_free;
981 }
982
983 return(0);
984
985 out_put:
986 iput(root_inode);
987 out_free:
988 kfree(name);
989 out:
990 return(err);
991 }
992
993 static struct super_block *hostfs_read_sb(struct file_system_type *type,
994 int flags, const char *dev_name,
995 void *data)
996 {
997 return(get_sb_nodev(type, flags, data, hostfs_fill_sb_common));
998 }
999
1000 static struct file_system_type hostfs_type = {
1001 .owner = THIS_MODULE,
1002 .name = "hostfs",
1003 .get_sb = hostfs_read_sb,
1004 .kill_sb = kill_anon_super,
1005 .fs_flags = 0,
1006 };
1007
1008 static int __init init_hostfs(void)
1009 {
1010 return(register_filesystem(&hostfs_type));
1011 }
1012
1013 static void __exit exit_hostfs(void)
1014 {
1015 unregister_filesystem(&hostfs_type);
1016 }
1017
1018 module_init(init_hostfs)
1019 module_exit(exit_hostfs)
1020 MODULE_LICENSE("GPL");
1021
1022 /*
1023 * Overrides for Emacs so that we follow Linus's tabbing style.
1024 * Emacs will notice this stuff at the end of the file and automatically
1025 * adjust the settings for this buffer only. This must remain at the end
1026 * of the file.
1027 * ---------------------------------------------------------------------------
1028 * Local variables:
1029 * c-file-style: "linux"
1030 * End:
1031 */
Linux kernel - Deliverables
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