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1 /*
2 FUSE: Filesystem in Userspace
3 Copyright (C) 2001-2008 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/seq_file.h>
15 #include <linux/init.h>
16 #include <linux/module.h>
17 #include <linux/parser.h>
18 #include <linux/statfs.h>
19 #include <linux/random.h>
20 #include <linux/sched.h>
21 #include <linux/exportfs.h>
22
23 MODULE_AUTHOR("Miklos Szeredi <miklos@szeredi.hu>");
24 MODULE_DESCRIPTION("Filesystem in Userspace");
25 MODULE_LICENSE("GPL");
26
27 static struct kmem_cache *fuse_inode_cachep;
28 struct list_head fuse_conn_list;
29 DEFINE_MUTEX(fuse_mutex);
30
31 #define FUSE_SUPER_MAGIC 0x65735546
32
33 #define FUSE_DEFAULT_BLKSIZE 512
34
35 struct fuse_mount_data {
36 int fd;
37 unsigned rootmode;
38 unsigned user_id;
39 unsigned group_id;
40 unsigned fd_present:1;
41 unsigned rootmode_present:1;
42 unsigned user_id_present:1;
43 unsigned group_id_present:1;
44 unsigned flags;
45 unsigned max_read;
46 unsigned blksize;
47 };
48
49 static struct inode *fuse_alloc_inode(struct super_block *sb)
50 {
51 struct inode *inode;
52 struct fuse_inode *fi;
53
54 inode = kmem_cache_alloc(fuse_inode_cachep, GFP_KERNEL);
55 if (!inode)
56 return NULL;
57
58 fi = get_fuse_inode(inode);
59 fi->i_time = 0;
60 fi->nodeid = 0;
61 fi->nlookup = 0;
62 fi->attr_version = 0;
63 fi->writectr = 0;
64 INIT_LIST_HEAD(&fi->write_files);
65 INIT_LIST_HEAD(&fi->queued_writes);
66 INIT_LIST_HEAD(&fi->writepages);
67 init_waitqueue_head(&fi->page_waitq);
68 fi->forget_req = fuse_request_alloc();
69 if (!fi->forget_req) {
70 kmem_cache_free(fuse_inode_cachep, inode);
71 return NULL;
72 }
73
74 return inode;
75 }
76
77 static void fuse_destroy_inode(struct inode *inode)
78 {
79 struct fuse_inode *fi = get_fuse_inode(inode);
80 BUG_ON(!list_empty(&fi->write_files));
81 BUG_ON(!list_empty(&fi->queued_writes));
82 if (fi->forget_req)
83 fuse_request_free(fi->forget_req);
84 kmem_cache_free(fuse_inode_cachep, inode);
85 }
86
87 void fuse_send_forget(struct fuse_conn *fc, struct fuse_req *req,
88 u64 nodeid, u64 nlookup)
89 {
90 struct fuse_forget_in *inarg = &req->misc.forget_in;
91 inarg->nlookup = nlookup;
92 req->in.h.opcode = FUSE_FORGET;
93 req->in.h.nodeid = nodeid;
94 req->in.numargs = 1;
95 req->in.args[0].size = sizeof(struct fuse_forget_in);
96 req->in.args[0].value = inarg;
97 request_send_noreply(fc, req);
98 }
99
100 static void fuse_clear_inode(struct inode *inode)
101 {
102 if (inode->i_sb->s_flags & MS_ACTIVE) {
103 struct fuse_conn *fc = get_fuse_conn(inode);
104 struct fuse_inode *fi = get_fuse_inode(inode);
105 fuse_send_forget(fc, fi->forget_req, fi->nodeid, fi->nlookup);
106 fi->forget_req = NULL;
107 }
108 }
109
110 static int fuse_remount_fs(struct super_block *sb, int *flags, char *data)
111 {
112 if (*flags & MS_MANDLOCK)
113 return -EINVAL;
114
115 return 0;
116 }
117
118 void fuse_truncate(struct address_space *mapping, loff_t offset)
119 {
120 /* See vmtruncate() */
121 unmap_mapping_range(mapping, offset + PAGE_SIZE - 1, 0, 1);
122 truncate_inode_pages(mapping, offset);
123 unmap_mapping_range(mapping, offset + PAGE_SIZE - 1, 0, 1);
124 }
125
126 void fuse_change_attributes_common(struct inode *inode, struct fuse_attr *attr,
127 u64 attr_valid)
128 {
129 struct fuse_conn *fc = get_fuse_conn(inode);
130 struct fuse_inode *fi = get_fuse_inode(inode);
131
132 fi->attr_version = ++fc->attr_version;
133 fi->i_time = attr_valid;
134
135 inode->i_ino = attr->ino;
136 inode->i_mode = (inode->i_mode & S_IFMT) | (attr->mode & 07777);
137 inode->i_nlink = attr->nlink;
138 inode->i_uid = attr->uid;
139 inode->i_gid = attr->gid;
140 inode->i_blocks = attr->blocks;
141 inode->i_atime.tv_sec = attr->atime;
142 inode->i_atime.tv_nsec = attr->atimensec;
143 inode->i_mtime.tv_sec = attr->mtime;
144 inode->i_mtime.tv_nsec = attr->mtimensec;
145 inode->i_ctime.tv_sec = attr->ctime;
146 inode->i_ctime.tv_nsec = attr->ctimensec;
147
148 if (attr->blksize != 0)
149 inode->i_blkbits = ilog2(attr->blksize);
150 else
151 inode->i_blkbits = inode->i_sb->s_blocksize_bits;
152
153 /*
154 * Don't set the sticky bit in i_mode, unless we want the VFS
155 * to check permissions. This prevents failures due to the
156 * check in may_delete().
157 */
158 fi->orig_i_mode = inode->i_mode;
159 if (!(fc->flags & FUSE_DEFAULT_PERMISSIONS))
160 inode->i_mode &= ~S_ISVTX;
161 }
162
163 void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr,
164 u64 attr_valid, u64 attr_version)
165 {
166 struct fuse_conn *fc = get_fuse_conn(inode);
167 struct fuse_inode *fi = get_fuse_inode(inode);
168 loff_t oldsize;
169
170 spin_lock(&fc->lock);
171 if (attr_version != 0 && fi->attr_version > attr_version) {
172 spin_unlock(&fc->lock);
173 return;
174 }
175
176 fuse_change_attributes_common(inode, attr, attr_valid);
177
178 oldsize = inode->i_size;
179 i_size_write(inode, attr->size);
180 spin_unlock(&fc->lock);
181
182 if (S_ISREG(inode->i_mode) && oldsize != attr->size) {
183 if (attr->size < oldsize)
184 fuse_truncate(inode->i_mapping, attr->size);
185 invalidate_inode_pages2(inode->i_mapping);
186 }
187 }
188
189 static void fuse_init_inode(struct inode *inode, struct fuse_attr *attr)
190 {
191 inode->i_mode = attr->mode & S_IFMT;
192 inode->i_size = attr->size;
193 if (S_ISREG(inode->i_mode)) {
194 fuse_init_common(inode);
195 fuse_init_file_inode(inode);
196 } else if (S_ISDIR(inode->i_mode))
197 fuse_init_dir(inode);
198 else if (S_ISLNK(inode->i_mode))
199 fuse_init_symlink(inode);
200 else if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode) ||
201 S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode)) {
202 fuse_init_common(inode);
203 init_special_inode(inode, inode->i_mode,
204 new_decode_dev(attr->rdev));
205 } else
206 BUG();
207 }
208
209 static int fuse_inode_eq(struct inode *inode, void *_nodeidp)
210 {
211 u64 nodeid = *(u64 *) _nodeidp;
212 if (get_node_id(inode) == nodeid)
213 return 1;
214 else
215 return 0;
216 }
217
218 static int fuse_inode_set(struct inode *inode, void *_nodeidp)
219 {
220 u64 nodeid = *(u64 *) _nodeidp;
221 get_fuse_inode(inode)->nodeid = nodeid;
222 return 0;
223 }
224
225 struct inode *fuse_iget(struct super_block *sb, u64 nodeid,
226 int generation, struct fuse_attr *attr,
227 u64 attr_valid, u64 attr_version)
228 {
229 struct inode *inode;
230 struct fuse_inode *fi;
231 struct fuse_conn *fc = get_fuse_conn_super(sb);
232
233 retry:
234 inode = iget5_locked(sb, nodeid, fuse_inode_eq, fuse_inode_set, &nodeid);
235 if (!inode)
236 return NULL;
237
238 if ((inode->i_state & I_NEW)) {
239 inode->i_flags |= S_NOATIME|S_NOCMTIME;
240 inode->i_generation = generation;
241 inode->i_data.backing_dev_info = &fc->bdi;
242 fuse_init_inode(inode, attr);
243 unlock_new_inode(inode);
244 } else if ((inode->i_mode ^ attr->mode) & S_IFMT) {
245 /* Inode has changed type, any I/O on the old should fail */
246 make_bad_inode(inode);
247 iput(inode);
248 goto retry;
249 }
250
251 fi = get_fuse_inode(inode);
252 spin_lock(&fc->lock);
253 fi->nlookup++;
254 spin_unlock(&fc->lock);
255 fuse_change_attributes(inode, attr, attr_valid, attr_version);
256
257 return inode;
258 }
259
260 static void fuse_umount_begin(struct super_block *sb)
261 {
262 fuse_abort_conn(get_fuse_conn_super(sb));
263 }
264
265 static void fuse_send_destroy(struct fuse_conn *fc)
266 {
267 struct fuse_req *req = fc->destroy_req;
268 if (req && fc->conn_init) {
269 fc->destroy_req = NULL;
270 req->in.h.opcode = FUSE_DESTROY;
271 req->force = 1;
272 request_send(fc, req);
273 fuse_put_request(fc, req);
274 }
275 }
276
277 static void fuse_put_super(struct super_block *sb)
278 {
279 struct fuse_conn *fc = get_fuse_conn_super(sb);
280
281 fuse_send_destroy(fc);
282 spin_lock(&fc->lock);
283 fc->connected = 0;
284 fc->blocked = 0;
285 spin_unlock(&fc->lock);
286 /* Flush all readers on this fs */
287 kill_fasync(&fc->fasync, SIGIO, POLL_IN);
288 wake_up_all(&fc->waitq);
289 wake_up_all(&fc->blocked_waitq);
290 wake_up_all(&fc->reserved_req_waitq);
291 mutex_lock(&fuse_mutex);
292 list_del(&fc->entry);
293 fuse_ctl_remove_conn(fc);
294 mutex_unlock(&fuse_mutex);
295 fuse_conn_put(fc);
296 }
297
298 static void convert_fuse_statfs(struct kstatfs *stbuf, struct fuse_kstatfs *attr)
299 {
300 stbuf->f_type = FUSE_SUPER_MAGIC;
301 stbuf->f_bsize = attr->bsize;
302 stbuf->f_frsize = attr->frsize;
303 stbuf->f_blocks = attr->blocks;
304 stbuf->f_bfree = attr->bfree;
305 stbuf->f_bavail = attr->bavail;
306 stbuf->f_files = attr->files;
307 stbuf->f_ffree = attr->ffree;
308 stbuf->f_namelen = attr->namelen;
309 /* fsid is left zero */
310 }
311
312 static int fuse_statfs(struct dentry *dentry, struct kstatfs *buf)
313 {
314 struct super_block *sb = dentry->d_sb;
315 struct fuse_conn *fc = get_fuse_conn_super(sb);
316 struct fuse_req *req;
317 struct fuse_statfs_out outarg;
318 int err;
319
320 if (!fuse_allow_task(fc, current)) {
321 buf->f_type = FUSE_SUPER_MAGIC;
322 return 0;
323 }
324
325 req = fuse_get_req(fc);
326 if (IS_ERR(req))
327 return PTR_ERR(req);
328
329 memset(&outarg, 0, sizeof(outarg));
330 req->in.numargs = 0;
331 req->in.h.opcode = FUSE_STATFS;
332 req->in.h.nodeid = get_node_id(dentry->d_inode);
333 req->out.numargs = 1;
334 req->out.args[0].size =
335 fc->minor < 4 ? FUSE_COMPAT_STATFS_SIZE : sizeof(outarg);
336 req->out.args[0].value = &outarg;
337 request_send(fc, req);
338 err = req->out.h.error;
339 if (!err)
340 convert_fuse_statfs(buf, &outarg.st);
341 fuse_put_request(fc, req);
342 return err;
343 }
344
345 enum {
346 OPT_FD,
347 OPT_ROOTMODE,
348 OPT_USER_ID,
349 OPT_GROUP_ID,
350 OPT_DEFAULT_PERMISSIONS,
351 OPT_ALLOW_OTHER,
352 OPT_MAX_READ,
353 OPT_BLKSIZE,
354 OPT_ERR
355 };
356
357 static const match_table_t tokens = {
358 {OPT_FD, "fd=%u"},
359 {OPT_ROOTMODE, "rootmode=%o"},
360 {OPT_USER_ID, "user_id=%u"},
361 {OPT_GROUP_ID, "group_id=%u"},
362 {OPT_DEFAULT_PERMISSIONS, "default_permissions"},
363 {OPT_ALLOW_OTHER, "allow_other"},
364 {OPT_MAX_READ, "max_read=%u"},
365 {OPT_BLKSIZE, "blksize=%u"},
366 {OPT_ERR, NULL}
367 };
368
369 static int parse_fuse_opt(char *opt, struct fuse_mount_data *d, int is_bdev)
370 {
371 char *p;
372 memset(d, 0, sizeof(struct fuse_mount_data));
373 d->max_read = ~0;
374 d->blksize = FUSE_DEFAULT_BLKSIZE;
375
376 while ((p = strsep(&opt, ",")) != NULL) {
377 int token;
378 int value;
379 substring_t args[MAX_OPT_ARGS];
380 if (!*p)
381 continue;
382
383 token = match_token(p, tokens, args);
384 switch (token) {
385 case OPT_FD:
386 if (match_int(&args[0], &value))
387 return 0;
388 d->fd = value;
389 d->fd_present = 1;
390 break;
391
392 case OPT_ROOTMODE:
393 if (match_octal(&args[0], &value))
394 return 0;
395 if (!fuse_valid_type(value))
396 return 0;
397 d->rootmode = value;
398 d->rootmode_present = 1;
399 break;
400
401 case OPT_USER_ID:
402 if (match_int(&args[0], &value))
403 return 0;
404 d->user_id = value;
405 d->user_id_present = 1;
406 break;
407
408 case OPT_GROUP_ID:
409 if (match_int(&args[0], &value))
410 return 0;
411 d->group_id = value;
412 d->group_id_present = 1;
413 break;
414
415 case OPT_DEFAULT_PERMISSIONS:
416 d->flags |= FUSE_DEFAULT_PERMISSIONS;
417 break;
418
419 case OPT_ALLOW_OTHER:
420 d->flags |= FUSE_ALLOW_OTHER;
421 break;
422
423 case OPT_MAX_READ:
424 if (match_int(&args[0], &value))
425 return 0;
426 d->max_read = value;
427 break;
428
429 case OPT_BLKSIZE:
430 if (!is_bdev || match_int(&args[0], &value))
431 return 0;
432 d->blksize = value;
433 break;
434
435 default:
436 return 0;
437 }
438 }
439
440 if (!d->fd_present || !d->rootmode_present ||
441 !d->user_id_present || !d->group_id_present)
442 return 0;
443
444 return 1;
445 }
446
447 static int fuse_show_options(struct seq_file *m, struct vfsmount *mnt)
448 {
449 struct fuse_conn *fc = get_fuse_conn_super(mnt->mnt_sb);
450
451 seq_printf(m, ",user_id=%u", fc->user_id);
452 seq_printf(m, ",group_id=%u", fc->group_id);
453 if (fc->flags & FUSE_DEFAULT_PERMISSIONS)
454 seq_puts(m, ",default_permissions");
455 if (fc->flags & FUSE_ALLOW_OTHER)
456 seq_puts(m, ",allow_other");
457 if (fc->max_read != ~0)
458 seq_printf(m, ",max_read=%u", fc->max_read);
459 if (mnt->mnt_sb->s_bdev &&
460 mnt->mnt_sb->s_blocksize != FUSE_DEFAULT_BLKSIZE)
461 seq_printf(m, ",blksize=%lu", mnt->mnt_sb->s_blocksize);
462 return 0;
463 }
464
465 static struct fuse_conn *new_conn(struct super_block *sb)
466 {
467 struct fuse_conn *fc;
468 int err;
469
470 fc = kzalloc(sizeof(*fc), GFP_KERNEL);
471 if (fc) {
472 spin_lock_init(&fc->lock);
473 mutex_init(&fc->inst_mutex);
474 atomic_set(&fc->count, 1);
475 init_waitqueue_head(&fc->waitq);
476 init_waitqueue_head(&fc->blocked_waitq);
477 init_waitqueue_head(&fc->reserved_req_waitq);
478 INIT_LIST_HEAD(&fc->pending);
479 INIT_LIST_HEAD(&fc->processing);
480 INIT_LIST_HEAD(&fc->io);
481 INIT_LIST_HEAD(&fc->interrupts);
482 INIT_LIST_HEAD(&fc->bg_queue);
483 atomic_set(&fc->num_waiting, 0);
484 fc->bdi.ra_pages = (VM_MAX_READAHEAD * 1024) / PAGE_CACHE_SIZE;
485 fc->bdi.unplug_io_fn = default_unplug_io_fn;
486 /* fuse does it's own writeback accounting */
487 fc->bdi.capabilities = BDI_CAP_NO_ACCT_WB;
488 fc->dev = sb->s_dev;
489 err = bdi_init(&fc->bdi);
490 if (err)
491 goto error_kfree;
492 if (sb->s_bdev) {
493 err = bdi_register(&fc->bdi, NULL, "%u:%u-fuseblk",
494 MAJOR(fc->dev), MINOR(fc->dev));
495 } else {
496 err = bdi_register_dev(&fc->bdi, fc->dev);
497 }
498 if (err)
499 goto error_bdi_destroy;
500 /*
501 * For a single fuse filesystem use max 1% of dirty +
502 * writeback threshold.
503 *
504 * This gives about 1M of write buffer for memory maps on a
505 * machine with 1G and 10% dirty_ratio, which should be more
506 * than enough.
507 *
508 * Privileged users can raise it by writing to
509 *
510 * /sys/class/bdi/<bdi>/max_ratio
511 */
512 bdi_set_max_ratio(&fc->bdi, 1);
513 fc->reqctr = 0;
514 fc->blocked = 1;
515 fc->attr_version = 1;
516 get_random_bytes(&fc->scramble_key, sizeof(fc->scramble_key));
517 }
518 return fc;
519
520 error_bdi_destroy:
521 bdi_destroy(&fc->bdi);
522 error_kfree:
523 mutex_destroy(&fc->inst_mutex);
524 kfree(fc);
525 return NULL;
526 }
527
528 void fuse_conn_put(struct fuse_conn *fc)
529 {
530 if (atomic_dec_and_test(&fc->count)) {
531 if (fc->destroy_req)
532 fuse_request_free(fc->destroy_req);
533 mutex_destroy(&fc->inst_mutex);
534 bdi_destroy(&fc->bdi);
535 kfree(fc);
536 }
537 }
538
539 struct fuse_conn *fuse_conn_get(struct fuse_conn *fc)
540 {
541 atomic_inc(&fc->count);
542 return fc;
543 }
544
545 static struct inode *get_root_inode(struct super_block *sb, unsigned mode)
546 {
547 struct fuse_attr attr;
548 memset(&attr, 0, sizeof(attr));
549
550 attr.mode = mode;
551 attr.ino = FUSE_ROOT_ID;
552 attr.nlink = 1;
553 return fuse_iget(sb, 1, 0, &attr, 0, 0);
554 }
555
556 struct fuse_inode_handle {
557 u64 nodeid;
558 u32 generation;
559 };
560
561 static struct dentry *fuse_get_dentry(struct super_block *sb,
562 struct fuse_inode_handle *handle)
563 {
564 struct fuse_conn *fc = get_fuse_conn_super(sb);
565 struct inode *inode;
566 struct dentry *entry;
567 int err = -ESTALE;
568
569 if (handle->nodeid == 0)
570 goto out_err;
571
572 inode = ilookup5(sb, handle->nodeid, fuse_inode_eq, &handle->nodeid);
573 if (!inode) {
574 struct fuse_entry_out outarg;
575 struct qstr name;
576
577 if (!fc->export_support)
578 goto out_err;
579
580 name.len = 1;
581 name.name = ".";
582 err = fuse_lookup_name(sb, handle->nodeid, &name, &outarg,
583 &inode);
584 if (err && err != -ENOENT)
585 goto out_err;
586 if (err || !inode) {
587 err = -ESTALE;
588 goto out_err;
589 }
590 err = -EIO;
591 if (get_node_id(inode) != handle->nodeid)
592 goto out_iput;
593 }
594 err = -ESTALE;
595 if (inode->i_generation != handle->generation)
596 goto out_iput;
597
598 entry = d_obtain_alias(inode);
599 if (!IS_ERR(entry) && get_node_id(inode) != FUSE_ROOT_ID) {
600 entry->d_op = &fuse_dentry_operations;
601 fuse_invalidate_entry_cache(entry);
602 }
603
604 return entry;
605
606 out_iput:
607 iput(inode);
608 out_err:
609 return ERR_PTR(err);
610 }
611
612 static int fuse_encode_fh(struct dentry *dentry, u32 *fh, int *max_len,
613 int connectable)
614 {
615 struct inode *inode = dentry->d_inode;
616 bool encode_parent = connectable && !S_ISDIR(inode->i_mode);
617 int len = encode_parent ? 6 : 3;
618 u64 nodeid;
619 u32 generation;
620
621 if (*max_len < len)
622 return 255;
623
624 nodeid = get_fuse_inode(inode)->nodeid;
625 generation = inode->i_generation;
626
627 fh[0] = (u32)(nodeid >> 32);
628 fh[1] = (u32)(nodeid & 0xffffffff);
629 fh[2] = generation;
630
631 if (encode_parent) {
632 struct inode *parent;
633
634 spin_lock(&dentry->d_lock);
635 parent = dentry->d_parent->d_inode;
636 nodeid = get_fuse_inode(parent)->nodeid;
637 generation = parent->i_generation;
638 spin_unlock(&dentry->d_lock);
639
640 fh[3] = (u32)(nodeid >> 32);
641 fh[4] = (u32)(nodeid & 0xffffffff);
642 fh[5] = generation;
643 }
644
645 *max_len = len;
646 return encode_parent ? 0x82 : 0x81;
647 }
648
649 static struct dentry *fuse_fh_to_dentry(struct super_block *sb,
650 struct fid *fid, int fh_len, int fh_type)
651 {
652 struct fuse_inode_handle handle;
653
654 if ((fh_type != 0x81 && fh_type != 0x82) || fh_len < 3)
655 return NULL;
656
657 handle.nodeid = (u64) fid->raw[0] << 32;
658 handle.nodeid |= (u64) fid->raw[1];
659 handle.generation = fid->raw[2];
660 return fuse_get_dentry(sb, &handle);
661 }
662
663 static struct dentry *fuse_fh_to_parent(struct super_block *sb,
664 struct fid *fid, int fh_len, int fh_type)
665 {
666 struct fuse_inode_handle parent;
667
668 if (fh_type != 0x82 || fh_len < 6)
669 return NULL;
670
671 parent.nodeid = (u64) fid->raw[3] << 32;
672 parent.nodeid |= (u64) fid->raw[4];
673 parent.generation = fid->raw[5];
674 return fuse_get_dentry(sb, &parent);
675 }
676
677 static struct dentry *fuse_get_parent(struct dentry *child)
678 {
679 struct inode *child_inode = child->d_inode;
680 struct fuse_conn *fc = get_fuse_conn(child_inode);
681 struct inode *inode;
682 struct dentry *parent;
683 struct fuse_entry_out outarg;
684 struct qstr name;
685 int err;
686
687 if (!fc->export_support)
688 return ERR_PTR(-ESTALE);
689
690 name.len = 2;
691 name.name = "..";
692 err = fuse_lookup_name(child_inode->i_sb, get_node_id(child_inode),
693 &name, &outarg, &inode);
694 if (err) {
695 if (err == -ENOENT)
696 return ERR_PTR(-ESTALE);
697 return ERR_PTR(err);
698 }
699
700 parent = d_obtain_alias(inode);
701 if (!IS_ERR(parent) && get_node_id(inode) != FUSE_ROOT_ID) {
702 parent->d_op = &fuse_dentry_operations;
703 fuse_invalidate_entry_cache(parent);
704 }
705
706 return parent;
707 }
708
709 static const struct export_operations fuse_export_operations = {
710 .fh_to_dentry = fuse_fh_to_dentry,
711 .fh_to_parent = fuse_fh_to_parent,
712 .encode_fh = fuse_encode_fh,
713 .get_parent = fuse_get_parent,
714 };
715
716 static const struct super_operations fuse_super_operations = {
717 .alloc_inode = fuse_alloc_inode,
718 .destroy_inode = fuse_destroy_inode,
719 .clear_inode = fuse_clear_inode,
720 .drop_inode = generic_delete_inode,
721 .remount_fs = fuse_remount_fs,
722 .put_super = fuse_put_super,
723 .umount_begin = fuse_umount_begin,
724 .statfs = fuse_statfs,
725 .show_options = fuse_show_options,
726 };
727
728 static void process_init_reply(struct fuse_conn *fc, struct fuse_req *req)
729 {
730 struct fuse_init_out *arg = &req->misc.init_out;
731
732 if (req->out.h.error || arg->major != FUSE_KERNEL_VERSION)
733 fc->conn_error = 1;
734 else {
735 unsigned long ra_pages;
736
737 if (arg->minor >= 6) {
738 ra_pages = arg->max_readahead / PAGE_CACHE_SIZE;
739 if (arg->flags & FUSE_ASYNC_READ)
740 fc->async_read = 1;
741 if (!(arg->flags & FUSE_POSIX_LOCKS))
742 fc->no_lock = 1;
743 if (arg->flags & FUSE_ATOMIC_O_TRUNC)
744 fc->atomic_o_trunc = 1;
745 if (arg->minor >= 9) {
746 /* LOOKUP has dependency on proto version */
747 if (arg->flags & FUSE_EXPORT_SUPPORT)
748 fc->export_support = 1;
749 }
750 if (arg->flags & FUSE_BIG_WRITES)
751 fc->big_writes = 1;
752 } else {
753 ra_pages = fc->max_read / PAGE_CACHE_SIZE;
754 fc->no_lock = 1;
755 }
756
757 fc->bdi.ra_pages = min(fc->bdi.ra_pages, ra_pages);
758 fc->minor = arg->minor;
759 fc->max_write = arg->minor < 5 ? 4096 : arg->max_write;
760 fc->max_write = max_t(unsigned, 4096, fc->max_write);
761 fc->conn_init = 1;
762 }
763 fuse_put_request(fc, req);
764 fc->blocked = 0;
765 wake_up_all(&fc->blocked_waitq);
766 }
767
768 static void fuse_send_init(struct fuse_conn *fc, struct fuse_req *req)
769 {
770 struct fuse_init_in *arg = &req->misc.init_in;
771
772 arg->major = FUSE_KERNEL_VERSION;
773 arg->minor = FUSE_KERNEL_MINOR_VERSION;
774 arg->max_readahead = fc->bdi.ra_pages * PAGE_CACHE_SIZE;
775 arg->flags |= FUSE_ASYNC_READ | FUSE_POSIX_LOCKS | FUSE_ATOMIC_O_TRUNC |
776 FUSE_EXPORT_SUPPORT | FUSE_BIG_WRITES;
777 req->in.h.opcode = FUSE_INIT;
778 req->in.numargs = 1;
779 req->in.args[0].size = sizeof(*arg);
780 req->in.args[0].value = arg;
781 req->out.numargs = 1;
782 /* Variable length arguement used for backward compatibility
783 with interface version < 7.5. Rest of init_out is zeroed
784 by do_get_request(), so a short reply is not a problem */
785 req->out.argvar = 1;
786 req->out.args[0].size = sizeof(struct fuse_init_out);
787 req->out.args[0].value = &req->misc.init_out;
788 req->end = process_init_reply;
789 request_send_background(fc, req);
790 }
791
792 static int fuse_fill_super(struct super_block *sb, void *data, int silent)
793 {
794 struct fuse_conn *fc;
795 struct inode *root;
796 struct fuse_mount_data d;
797 struct file *file;
798 struct dentry *root_dentry;
799 struct fuse_req *init_req;
800 int err;
801 int is_bdev = sb->s_bdev != NULL;
802
803 if (sb->s_flags & MS_MANDLOCK)
804 return -EINVAL;
805
806 if (!parse_fuse_opt((char *) data, &d, is_bdev))
807 return -EINVAL;
808
809 if (is_bdev) {
810 #ifdef CONFIG_BLOCK
811 if (!sb_set_blocksize(sb, d.blksize))
812 return -EINVAL;
813 #endif
814 } else {
815 sb->s_blocksize = PAGE_CACHE_SIZE;
816 sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
817 }
818 sb->s_magic = FUSE_SUPER_MAGIC;
819 sb->s_op = &fuse_super_operations;
820 sb->s_maxbytes = MAX_LFS_FILESIZE;
821 sb->s_export_op = &fuse_export_operations;
822
823 file = fget(d.fd);
824 if (!file)
825 return -EINVAL;
826
827 if (file->f_op != &fuse_dev_operations)
828 return -EINVAL;
829
830 fc = new_conn(sb);
831 if (!fc)
832 return -ENOMEM;
833
834 fc->flags = d.flags;
835 fc->user_id = d.user_id;
836 fc->group_id = d.group_id;
837 fc->max_read = max_t(unsigned, 4096, d.max_read);
838
839 /* Used by get_root_inode() */
840 sb->s_fs_info = fc;
841
842 err = -ENOMEM;
843 root = get_root_inode(sb, d.rootmode);
844 if (!root)
845 goto err;
846
847 root_dentry = d_alloc_root(root);
848 if (!root_dentry) {
849 iput(root);
850 goto err;
851 }
852
853 init_req = fuse_request_alloc();
854 if (!init_req)
855 goto err_put_root;
856
857 if (is_bdev) {
858 fc->destroy_req = fuse_request_alloc();
859 if (!fc->destroy_req)
860 goto err_free_init_req;
861 }
862
863 mutex_lock(&fuse_mutex);
864 err = -EINVAL;
865 if (file->private_data)
866 goto err_unlock;
867
868 err = fuse_ctl_add_conn(fc);
869 if (err)
870 goto err_unlock;
871
872 list_add_tail(&fc->entry, &fuse_conn_list);
873 sb->s_root = root_dentry;
874 fc->connected = 1;
875 file->private_data = fuse_conn_get(fc);
876 mutex_unlock(&fuse_mutex);
877 /*
878 * atomic_dec_and_test() in fput() provides the necessary
879 * memory barrier for file->private_data to be visible on all
880 * CPUs after this
881 */
882 fput(file);
883
884 fuse_send_init(fc, init_req);
885
886 return 0;
887
888 err_unlock:
889 mutex_unlock(&fuse_mutex);
890 err_free_init_req:
891 fuse_request_free(init_req);
892 err_put_root:
893 dput(root_dentry);
894 err:
895 fput(file);
896 fuse_conn_put(fc);
897 return err;
898 }
899
900 static int fuse_get_sb(struct file_system_type *fs_type,
901 int flags, const char *dev_name,
902 void *raw_data, struct vfsmount *mnt)
903 {
904 return get_sb_nodev(fs_type, flags, raw_data, fuse_fill_super, mnt);
905 }
906
907 static struct file_system_type fuse_fs_type = {
908 .owner = THIS_MODULE,
909 .name = "fuse",
910 .fs_flags = FS_HAS_SUBTYPE,
911 .get_sb = fuse_get_sb,
912 .kill_sb = kill_anon_super,
913 };
914
915 #ifdef CONFIG_BLOCK
916 static int fuse_get_sb_blk(struct file_system_type *fs_type,
917 int flags, const char *dev_name,
918 void *raw_data, struct vfsmount *mnt)
919 {
920 return get_sb_bdev(fs_type, flags, dev_name, raw_data, fuse_fill_super,
921 mnt);
922 }
923
924 static struct file_system_type fuseblk_fs_type = {
925 .owner = THIS_MODULE,
926 .name = "fuseblk",
927 .get_sb = fuse_get_sb_blk,
928 .kill_sb = kill_block_super,
929 .fs_flags = FS_REQUIRES_DEV | FS_HAS_SUBTYPE,
930 };
931
932 static inline int register_fuseblk(void)
933 {
934 return register_filesystem(&fuseblk_fs_type);
935 }
936
937 static inline void unregister_fuseblk(void)
938 {
939 unregister_filesystem(&fuseblk_fs_type);
940 }
941 #else
942 static inline int register_fuseblk(void)
943 {
944 return 0;
945 }
946
947 static inline void unregister_fuseblk(void)
948 {
949 }
950 #endif
951
952 static void fuse_inode_init_once(void *foo)
953 {
954 struct inode *inode = foo;
955
956 inode_init_once(inode);
957 }
958
959 static int __init fuse_fs_init(void)
960 {
961 int err;
962
963 err = register_filesystem(&fuse_fs_type);
964 if (err)
965 goto out;
966
967 err = register_fuseblk();
968 if (err)
969 goto out_unreg;
970
971 fuse_inode_cachep = kmem_cache_create("fuse_inode",
972 sizeof(struct fuse_inode),
973 0, SLAB_HWCACHE_ALIGN,
974 fuse_inode_init_once);
975 err = -ENOMEM;
976 if (!fuse_inode_cachep)
977 goto out_unreg2;
978
979 return 0;
980
981 out_unreg2:
982 unregister_fuseblk();
983 out_unreg:
984 unregister_filesystem(&fuse_fs_type);
985 out:
986 return err;
987 }
988
989 static void fuse_fs_cleanup(void)
990 {
991 unregister_filesystem(&fuse_fs_type);
992 unregister_fuseblk();
993 kmem_cache_destroy(fuse_inode_cachep);
994 }
995
996 static struct kobject *fuse_kobj;
997 static struct kobject *connections_kobj;
998
999 static int fuse_sysfs_init(void)
1000 {
1001 int err;
1002
1003 fuse_kobj = kobject_create_and_add("fuse", fs_kobj);
1004 if (!fuse_kobj) {
1005 err = -ENOMEM;
1006 goto out_err;
1007 }
1008
1009 connections_kobj = kobject_create_and_add("connections", fuse_kobj);
1010 if (!connections_kobj) {
1011 err = -ENOMEM;
1012 goto out_fuse_unregister;
1013 }
1014
1015 return 0;
1016
1017 out_fuse_unregister:
1018 kobject_put(fuse_kobj);
1019 out_err:
1020 return err;
1021 }
1022
1023 static void fuse_sysfs_cleanup(void)
1024 {
1025 kobject_put(connections_kobj);
1026 kobject_put(fuse_kobj);
1027 }
1028
1029 static int __init fuse_init(void)
1030 {
1031 int res;
1032
1033 printk(KERN_INFO "fuse init (API version %i.%i)\n",
1034 FUSE_KERNEL_VERSION, FUSE_KERNEL_MINOR_VERSION);
1035
1036 INIT_LIST_HEAD(&fuse_conn_list);
1037 res = fuse_fs_init();
1038 if (res)
1039 goto err;
1040
1041 res = fuse_dev_init();
1042 if (res)
1043 goto err_fs_cleanup;
1044
1045 res = fuse_sysfs_init();
1046 if (res)
1047 goto err_dev_cleanup;
1048
1049 res = fuse_ctl_init();
1050 if (res)
1051 goto err_sysfs_cleanup;
1052
1053 return 0;
1054
1055 err_sysfs_cleanup:
1056 fuse_sysfs_cleanup();
1057 err_dev_cleanup:
1058 fuse_dev_cleanup();
1059 err_fs_cleanup:
1060 fuse_fs_cleanup();
1061 err:
1062 return res;
1063 }
1064
1065 static void __exit fuse_exit(void)
1066 {
1067 printk(KERN_DEBUG "fuse exit\n");
1068
1069 fuse_ctl_cleanup();
1070 fuse_sysfs_cleanup();
1071 fuse_fs_cleanup();
1072 fuse_dev_cleanup();
1073 }
1074
1075 module_init(fuse_init);
1076 module_exit(fuse_exit);