fa03f80806e5dd84f5a732eefdff9c10b205c631
[deliverable/linux.git] / fs / fuse / inode.c
1 /*
2 FUSE: Filesystem in Userspace
3 Copyright (C) 2001-2005 Miklos Szeredi <miklos@szeredi.hu>
4
5 This program can be distributed under the terms of the GNU GPL.
6 See the file COPYING.
7 */
8
9 #include "fuse_i.h"
10
11 #include <linux/pagemap.h>
12 #include <linux/slab.h>
13 #include <linux/file.h>
14 #include <linux/mount.h>
15 #include <linux/seq_file.h>
16 #include <linux/init.h>
17 #include <linux/module.h>
18 #include <linux/moduleparam.h>
19 #include <linux/parser.h>
20 #include <linux/statfs.h>
21
22 MODULE_AUTHOR("Miklos Szeredi <miklos@szeredi.hu>");
23 MODULE_DESCRIPTION("Filesystem in Userspace");
24 MODULE_LICENSE("GPL");
25
26 spinlock_t fuse_lock;
27 static kmem_cache_t *fuse_inode_cachep;
28 static int mount_count;
29
30 static int mount_max = 1000;
31 module_param(mount_max, int, 0644);
32 MODULE_PARM_DESC(mount_max, "Maximum number of FUSE mounts allowed, if -1 then unlimited (default: 1000)");
33
34 #define FUSE_SUPER_MAGIC 0x65735546
35
36 struct fuse_mount_data {
37 int fd;
38 unsigned rootmode;
39 unsigned user_id;
40 };
41
42 static struct inode *fuse_alloc_inode(struct super_block *sb)
43 {
44 struct inode *inode;
45 struct fuse_inode *fi;
46
47 inode = kmem_cache_alloc(fuse_inode_cachep, SLAB_KERNEL);
48 if (!inode)
49 return NULL;
50
51 fi = get_fuse_inode(inode);
52 fi->i_time = jiffies - 1;
53 fi->nodeid = 0;
54 fi->nlookup = 0;
55 fi->forget_req = fuse_request_alloc();
56 if (!fi->forget_req) {
57 kmem_cache_free(fuse_inode_cachep, inode);
58 return NULL;
59 }
60
61 return inode;
62 }
63
64 static void fuse_destroy_inode(struct inode *inode)
65 {
66 struct fuse_inode *fi = get_fuse_inode(inode);
67 if (fi->forget_req)
68 fuse_request_free(fi->forget_req);
69 kmem_cache_free(fuse_inode_cachep, inode);
70 }
71
72 static void fuse_read_inode(struct inode *inode)
73 {
74 /* No op */
75 }
76
77 void fuse_send_forget(struct fuse_conn *fc, struct fuse_req *req,
78 unsigned long nodeid, u64 nlookup)
79 {
80 struct fuse_forget_in *inarg = &req->misc.forget_in;
81 inarg->nlookup = nlookup;
82 req->in.h.opcode = FUSE_FORGET;
83 req->in.h.nodeid = nodeid;
84 req->in.numargs = 1;
85 req->in.args[0].size = sizeof(struct fuse_forget_in);
86 req->in.args[0].value = inarg;
87 request_send_noreply(fc, req);
88 }
89
90 static void fuse_clear_inode(struct inode *inode)
91 {
92 struct fuse_conn *fc = get_fuse_conn(inode);
93 if (fc) {
94 struct fuse_inode *fi = get_fuse_inode(inode);
95 fuse_send_forget(fc, fi->forget_req, fi->nodeid, fi->nlookup);
96 fi->forget_req = NULL;
97 }
98 }
99
100 void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr)
101 {
102 if (S_ISREG(inode->i_mode) && i_size_read(inode) != attr->size)
103 invalidate_inode_pages(inode->i_mapping);
104
105 inode->i_ino = attr->ino;
106 inode->i_mode = (inode->i_mode & S_IFMT) + (attr->mode & 07777);
107 inode->i_nlink = attr->nlink;
108 inode->i_uid = attr->uid;
109 inode->i_gid = attr->gid;
110 i_size_write(inode, attr->size);
111 inode->i_blksize = PAGE_CACHE_SIZE;
112 inode->i_blocks = attr->blocks;
113 inode->i_atime.tv_sec = attr->atime;
114 inode->i_atime.tv_nsec = attr->atimensec;
115 inode->i_mtime.tv_sec = attr->mtime;
116 inode->i_mtime.tv_nsec = attr->mtimensec;
117 inode->i_ctime.tv_sec = attr->ctime;
118 inode->i_ctime.tv_nsec = attr->ctimensec;
119 }
120
121 static void fuse_init_inode(struct inode *inode, struct fuse_attr *attr)
122 {
123 inode->i_mode = attr->mode & S_IFMT;
124 i_size_write(inode, attr->size);
125 if (S_ISREG(inode->i_mode)) {
126 fuse_init_common(inode);
127 } else if (S_ISDIR(inode->i_mode))
128 fuse_init_dir(inode);
129 else if (S_ISLNK(inode->i_mode))
130 fuse_init_symlink(inode);
131 else if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode) ||
132 S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode)) {
133 fuse_init_common(inode);
134 init_special_inode(inode, inode->i_mode,
135 new_decode_dev(attr->rdev));
136 } else {
137 /* Don't let user create weird files */
138 inode->i_mode = S_IFREG;
139 fuse_init_common(inode);
140 }
141 }
142
143 static int fuse_inode_eq(struct inode *inode, void *_nodeidp)
144 {
145 unsigned long nodeid = *(unsigned long *) _nodeidp;
146 if (get_node_id(inode) == nodeid)
147 return 1;
148 else
149 return 0;
150 }
151
152 static int fuse_inode_set(struct inode *inode, void *_nodeidp)
153 {
154 unsigned long nodeid = *(unsigned long *) _nodeidp;
155 get_fuse_inode(inode)->nodeid = nodeid;
156 return 0;
157 }
158
159 struct inode *fuse_iget(struct super_block *sb, unsigned long nodeid,
160 int generation, struct fuse_attr *attr)
161 {
162 struct inode *inode;
163 struct fuse_inode *fi;
164 struct fuse_conn *fc = get_fuse_conn_super(sb);
165 int retried = 0;
166
167 retry:
168 inode = iget5_locked(sb, nodeid, fuse_inode_eq, fuse_inode_set, &nodeid);
169 if (!inode)
170 return NULL;
171
172 if ((inode->i_state & I_NEW)) {
173 inode->i_generation = generation;
174 inode->i_data.backing_dev_info = &fc->bdi;
175 fuse_init_inode(inode, attr);
176 unlock_new_inode(inode);
177 } else if ((inode->i_mode ^ attr->mode) & S_IFMT) {
178 BUG_ON(retried);
179 /* Inode has changed type, any I/O on the old should fail */
180 make_bad_inode(inode);
181 iput(inode);
182 retried = 1;
183 goto retry;
184 }
185
186 fi = get_fuse_inode(inode);
187 fi->nlookup ++;
188 fuse_change_attributes(inode, attr);
189 return inode;
190 }
191
192 static void fuse_put_super(struct super_block *sb)
193 {
194 struct fuse_conn *fc = get_fuse_conn_super(sb);
195
196 spin_lock(&fuse_lock);
197 mount_count --;
198 fc->sb = NULL;
199 fc->user_id = 0;
200 /* Flush all readers on this fs */
201 wake_up_all(&fc->waitq);
202 fuse_release_conn(fc);
203 *get_fuse_conn_super_p(sb) = NULL;
204 spin_unlock(&fuse_lock);
205 }
206
207 static void convert_fuse_statfs(struct kstatfs *stbuf, struct fuse_kstatfs *attr)
208 {
209 stbuf->f_type = FUSE_SUPER_MAGIC;
210 stbuf->f_bsize = attr->bsize;
211 stbuf->f_blocks = attr->blocks;
212 stbuf->f_bfree = attr->bfree;
213 stbuf->f_bavail = attr->bavail;
214 stbuf->f_files = attr->files;
215 stbuf->f_ffree = attr->ffree;
216 stbuf->f_namelen = attr->namelen;
217 /* fsid is left zero */
218 }
219
220 static int fuse_statfs(struct super_block *sb, struct kstatfs *buf)
221 {
222 struct fuse_conn *fc = get_fuse_conn_super(sb);
223 struct fuse_req *req;
224 struct fuse_statfs_out outarg;
225 int err;
226
227 req = fuse_get_request(fc);
228 if (!req)
229 return -ERESTARTSYS;
230
231 req->in.numargs = 0;
232 req->in.h.opcode = FUSE_STATFS;
233 req->out.numargs = 1;
234 req->out.args[0].size = sizeof(outarg);
235 req->out.args[0].value = &outarg;
236 request_send(fc, req);
237 err = req->out.h.error;
238 if (!err)
239 convert_fuse_statfs(buf, &outarg.st);
240 fuse_put_request(fc, req);
241 return err;
242 }
243
244 enum {
245 OPT_FD,
246 OPT_ROOTMODE,
247 OPT_USER_ID,
248 OPT_DEFAULT_PERMISSIONS,
249 OPT_ALLOW_OTHER,
250 OPT_ALLOW_ROOT,
251 OPT_KERNEL_CACHE,
252 OPT_ERR
253 };
254
255 static match_table_t tokens = {
256 {OPT_FD, "fd=%u"},
257 {OPT_ROOTMODE, "rootmode=%o"},
258 {OPT_USER_ID, "user_id=%u"},
259 {OPT_DEFAULT_PERMISSIONS, "default_permissions"},
260 {OPT_ALLOW_OTHER, "allow_other"},
261 {OPT_ALLOW_ROOT, "allow_root"},
262 {OPT_KERNEL_CACHE, "kernel_cache"},
263 {OPT_ERR, NULL}
264 };
265
266 static int parse_fuse_opt(char *opt, struct fuse_mount_data *d)
267 {
268 char *p;
269 memset(d, 0, sizeof(struct fuse_mount_data));
270 d->fd = -1;
271
272 while ((p = strsep(&opt, ",")) != NULL) {
273 int token;
274 int value;
275 substring_t args[MAX_OPT_ARGS];
276 if (!*p)
277 continue;
278
279 token = match_token(p, tokens, args);
280 switch (token) {
281 case OPT_FD:
282 if (match_int(&args[0], &value))
283 return 0;
284 d->fd = value;
285 break;
286
287 case OPT_ROOTMODE:
288 if (match_octal(&args[0], &value))
289 return 0;
290 d->rootmode = value;
291 break;
292
293 case OPT_USER_ID:
294 if (match_int(&args[0], &value))
295 return 0;
296 d->user_id = value;
297 break;
298
299 default:
300 return 0;
301 }
302 }
303 if (d->fd == -1)
304 return 0;
305
306 return 1;
307 }
308
309 static int fuse_show_options(struct seq_file *m, struct vfsmount *mnt)
310 {
311 struct fuse_conn *fc = get_fuse_conn_super(mnt->mnt_sb);
312
313 seq_printf(m, ",user_id=%u", fc->user_id);
314 return 0;
315 }
316
317 static void free_conn(struct fuse_conn *fc)
318 {
319 while (!list_empty(&fc->unused_list)) {
320 struct fuse_req *req;
321 req = list_entry(fc->unused_list.next, struct fuse_req, list);
322 list_del(&req->list);
323 fuse_request_free(req);
324 }
325 kfree(fc);
326 }
327
328 /* Must be called with the fuse lock held */
329 void fuse_release_conn(struct fuse_conn *fc)
330 {
331 if (!fc->sb && !fc->file)
332 free_conn(fc);
333 }
334
335 static struct fuse_conn *new_conn(void)
336 {
337 struct fuse_conn *fc;
338
339 fc = kmalloc(sizeof(*fc), GFP_KERNEL);
340 if (fc != NULL) {
341 int i;
342 memset(fc, 0, sizeof(*fc));
343 fc->sb = NULL;
344 fc->file = NULL;
345 fc->user_id = 0;
346 init_waitqueue_head(&fc->waitq);
347 INIT_LIST_HEAD(&fc->pending);
348 INIT_LIST_HEAD(&fc->processing);
349 INIT_LIST_HEAD(&fc->unused_list);
350 sema_init(&fc->outstanding_sem, 0);
351 for (i = 0; i < FUSE_MAX_OUTSTANDING; i++) {
352 struct fuse_req *req = fuse_request_alloc();
353 if (!req) {
354 free_conn(fc);
355 return NULL;
356 }
357 list_add(&req->list, &fc->unused_list);
358 }
359 fc->bdi.ra_pages = (VM_MAX_READAHEAD * 1024) / PAGE_CACHE_SIZE;
360 fc->bdi.unplug_io_fn = default_unplug_io_fn;
361 fc->reqctr = 0;
362 }
363 return fc;
364 }
365
366 static struct fuse_conn *get_conn(struct file *file, struct super_block *sb)
367 {
368 struct fuse_conn *fc;
369
370 if (file->f_op != &fuse_dev_operations)
371 return ERR_PTR(-EINVAL);
372 fc = new_conn();
373 if (fc == NULL)
374 return ERR_PTR(-ENOMEM);
375 spin_lock(&fuse_lock);
376 if (file->private_data) {
377 free_conn(fc);
378 fc = ERR_PTR(-EINVAL);
379 } else {
380 file->private_data = fc;
381 fc->sb = sb;
382 fc->file = file;
383 }
384 spin_unlock(&fuse_lock);
385 return fc;
386 }
387
388 static struct inode *get_root_inode(struct super_block *sb, unsigned mode)
389 {
390 struct fuse_attr attr;
391 memset(&attr, 0, sizeof(attr));
392
393 attr.mode = mode;
394 attr.ino = FUSE_ROOT_ID;
395 return fuse_iget(sb, 1, 0, &attr);
396 }
397
398 static struct super_operations fuse_super_operations = {
399 .alloc_inode = fuse_alloc_inode,
400 .destroy_inode = fuse_destroy_inode,
401 .read_inode = fuse_read_inode,
402 .clear_inode = fuse_clear_inode,
403 .put_super = fuse_put_super,
404 .statfs = fuse_statfs,
405 .show_options = fuse_show_options,
406 };
407
408 static int inc_mount_count(void)
409 {
410 int success = 0;
411 spin_lock(&fuse_lock);
412 mount_count ++;
413 if (mount_max == -1 || mount_count <= mount_max)
414 success = 1;
415 spin_unlock(&fuse_lock);
416 return success;
417 }
418
419 static int fuse_fill_super(struct super_block *sb, void *data, int silent)
420 {
421 struct fuse_conn *fc;
422 struct inode *root;
423 struct fuse_mount_data d;
424 struct file *file;
425 int err;
426
427 if (!parse_fuse_opt((char *) data, &d))
428 return -EINVAL;
429
430 sb->s_blocksize = PAGE_CACHE_SIZE;
431 sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
432 sb->s_magic = FUSE_SUPER_MAGIC;
433 sb->s_op = &fuse_super_operations;
434 sb->s_maxbytes = MAX_LFS_FILESIZE;
435
436 file = fget(d.fd);
437 if (!file)
438 return -EINVAL;
439
440 fc = get_conn(file, sb);
441 fput(file);
442 if (IS_ERR(fc))
443 return PTR_ERR(fc);
444
445 fc->user_id = d.user_id;
446
447 *get_fuse_conn_super_p(sb) = fc;
448
449 err = -ENFILE;
450 if (!inc_mount_count() && current->uid != 0)
451 goto err;
452
453 err = -ENOMEM;
454 root = get_root_inode(sb, d.rootmode);
455 if (root == NULL)
456 goto err;
457
458 sb->s_root = d_alloc_root(root);
459 if (!sb->s_root) {
460 iput(root);
461 goto err;
462 }
463 fuse_send_init(fc);
464 return 0;
465
466 err:
467 spin_lock(&fuse_lock);
468 mount_count --;
469 fc->sb = NULL;
470 fuse_release_conn(fc);
471 spin_unlock(&fuse_lock);
472 *get_fuse_conn_super_p(sb) = NULL;
473 return err;
474 }
475
476 static struct super_block *fuse_get_sb(struct file_system_type *fs_type,
477 int flags, const char *dev_name,
478 void *raw_data)
479 {
480 return get_sb_nodev(fs_type, flags, raw_data, fuse_fill_super);
481 }
482
483 static struct file_system_type fuse_fs_type = {
484 .owner = THIS_MODULE,
485 .name = "fuse",
486 .get_sb = fuse_get_sb,
487 .kill_sb = kill_anon_super,
488 };
489
490 static void fuse_inode_init_once(void *foo, kmem_cache_t *cachep,
491 unsigned long flags)
492 {
493 struct inode * inode = foo;
494
495 if ((flags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) ==
496 SLAB_CTOR_CONSTRUCTOR)
497 inode_init_once(inode);
498 }
499
500 static int __init fuse_fs_init(void)
501 {
502 int err;
503
504 err = register_filesystem(&fuse_fs_type);
505 if (err)
506 printk("fuse: failed to register filesystem\n");
507 else {
508 fuse_inode_cachep = kmem_cache_create("fuse_inode",
509 sizeof(struct fuse_inode),
510 0, SLAB_HWCACHE_ALIGN,
511 fuse_inode_init_once, NULL);
512 if (!fuse_inode_cachep) {
513 unregister_filesystem(&fuse_fs_type);
514 err = -ENOMEM;
515 }
516 }
517
518 return err;
519 }
520
521 static void fuse_fs_cleanup(void)
522 {
523 unregister_filesystem(&fuse_fs_type);
524 kmem_cache_destroy(fuse_inode_cachep);
525 }
526
527 static int __init fuse_init(void)
528 {
529 int res;
530
531 printk("fuse init (API version %i.%i)\n",
532 FUSE_KERNEL_VERSION, FUSE_KERNEL_MINOR_VERSION);
533
534 spin_lock_init(&fuse_lock);
535 res = fuse_fs_init();
536 if (res)
537 goto err;
538
539 res = fuse_dev_init();
540 if (res)
541 goto err_fs_cleanup;
542
543 return 0;
544
545 err_fs_cleanup:
546 fuse_fs_cleanup();
547 err:
548 return res;
549 }
550
551 static void __exit fuse_exit(void)
552 {
553 printk(KERN_DEBUG "fuse exit\n");
554
555 fuse_fs_cleanup();
556 fuse_dev_cleanup();
557 }
558
559 module_init(fuse_init);
560 module_exit(fuse_exit);
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