Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/roland...
[linux-2.6] / fs / fuse / inode.c
1 /*
2   FUSE: Filesystem in Userspace
3   Copyright (C) 2001-2006  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
22 MODULE_AUTHOR("Miklos Szeredi <miklos@szeredi.hu>");
23 MODULE_DESCRIPTION("Filesystem in Userspace");
24 MODULE_LICENSE("GPL");
25
26 static struct kmem_cache *fuse_inode_cachep;
27 struct list_head fuse_conn_list;
28 DEFINE_MUTEX(fuse_mutex);
29
30 #define FUSE_SUPER_MAGIC 0x65735546
31
32 #define FUSE_DEFAULT_BLKSIZE 512
33
34 struct fuse_mount_data {
35         int fd;
36         unsigned rootmode;
37         unsigned user_id;
38         unsigned group_id;
39         unsigned fd_present : 1;
40         unsigned rootmode_present : 1;
41         unsigned user_id_present : 1;
42         unsigned group_id_present : 1;
43         unsigned flags;
44         unsigned max_read;
45         unsigned blksize;
46 };
47
48 static struct inode *fuse_alloc_inode(struct super_block *sb)
49 {
50         struct inode *inode;
51         struct fuse_inode *fi;
52
53         inode = kmem_cache_alloc(fuse_inode_cachep, GFP_KERNEL);
54         if (!inode)
55                 return NULL;
56
57         fi = get_fuse_inode(inode);
58         fi->i_time = 0;
59         fi->nodeid = 0;
60         fi->nlookup = 0;
61         fi->attr_version = 0;
62         fi->writectr = 0;
63         INIT_LIST_HEAD(&fi->write_files);
64         INIT_LIST_HEAD(&fi->queued_writes);
65         INIT_LIST_HEAD(&fi->writepages);
66         init_waitqueue_head(&fi->page_waitq);
67         fi->forget_req = fuse_request_alloc();
68         if (!fi->forget_req) {
69                 kmem_cache_free(fuse_inode_cachep, inode);
70                 return NULL;
71         }
72
73         return inode;
74 }
75
76 static void fuse_destroy_inode(struct inode *inode)
77 {
78         struct fuse_inode *fi = get_fuse_inode(inode);
79         BUG_ON(!list_empty(&fi->write_files));
80         BUG_ON(!list_empty(&fi->queued_writes));
81         if (fi->forget_req)
82                 fuse_request_free(fi->forget_req);
83         kmem_cache_free(fuse_inode_cachep, inode);
84 }
85
86 void fuse_send_forget(struct fuse_conn *fc, struct fuse_req *req,
87                       u64 nodeid, u64 nlookup)
88 {
89         struct fuse_forget_in *inarg = &req->misc.forget_in;
90         inarg->nlookup = nlookup;
91         req->in.h.opcode = FUSE_FORGET;
92         req->in.h.nodeid = nodeid;
93         req->in.numargs = 1;
94         req->in.args[0].size = sizeof(struct fuse_forget_in);
95         req->in.args[0].value = inarg;
96         request_send_noreply(fc, req);
97 }
98
99 static void fuse_clear_inode(struct inode *inode)
100 {
101         if (inode->i_sb->s_flags & MS_ACTIVE) {
102                 struct fuse_conn *fc = get_fuse_conn(inode);
103                 struct fuse_inode *fi = get_fuse_inode(inode);
104                 fuse_send_forget(fc, fi->forget_req, fi->nodeid, fi->nlookup);
105                 fi->forget_req = NULL;
106         }
107 }
108
109 static int fuse_remount_fs(struct super_block *sb, int *flags, char *data)
110 {
111         if (*flags & MS_MANDLOCK)
112                 return -EINVAL;
113
114         return 0;
115 }
116
117 void fuse_truncate(struct address_space *mapping, loff_t offset)
118 {
119         /* See vmtruncate() */
120         unmap_mapping_range(mapping, offset + PAGE_SIZE - 1, 0, 1);
121         truncate_inode_pages(mapping, offset);
122         unmap_mapping_range(mapping, offset + PAGE_SIZE - 1, 0, 1);
123 }
124
125 void fuse_change_attributes_common(struct inode *inode, struct fuse_attr *attr,
126                                    u64 attr_valid)
127 {
128         struct fuse_conn *fc = get_fuse_conn(inode);
129         struct fuse_inode *fi = get_fuse_inode(inode);
130
131         fi->attr_version = ++fc->attr_version;
132         fi->i_time = attr_valid;
133
134         inode->i_ino     = attr->ino;
135         inode->i_mode    = (inode->i_mode & S_IFMT) | (attr->mode & 07777);
136         inode->i_nlink   = attr->nlink;
137         inode->i_uid     = attr->uid;
138         inode->i_gid     = attr->gid;
139         inode->i_blocks  = attr->blocks;
140         inode->i_atime.tv_sec   = attr->atime;
141         inode->i_atime.tv_nsec  = attr->atimensec;
142         inode->i_mtime.tv_sec   = attr->mtime;
143         inode->i_mtime.tv_nsec  = attr->mtimensec;
144         inode->i_ctime.tv_sec   = attr->ctime;
145         inode->i_ctime.tv_nsec  = attr->ctimensec;
146
147         if (attr->blksize != 0)
148                 inode->i_blkbits = ilog2(attr->blksize);
149         else
150                 inode->i_blkbits = inode->i_sb->s_blocksize_bits;
151
152         /*
153          * Don't set the sticky bit in i_mode, unless we want the VFS
154          * to check permissions.  This prevents failures due to the
155          * check in may_delete().
156          */
157         fi->orig_i_mode = inode->i_mode;
158         if (!(fc->flags & FUSE_DEFAULT_PERMISSIONS))
159                 inode->i_mode &= ~S_ISVTX;
160 }
161
162 void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr,
163                             u64 attr_valid, u64 attr_version)
164 {
165         struct fuse_conn *fc = get_fuse_conn(inode);
166         struct fuse_inode *fi = get_fuse_inode(inode);
167         loff_t oldsize;
168
169         spin_lock(&fc->lock);
170         if (attr_version != 0 && fi->attr_version > attr_version) {
171                 spin_unlock(&fc->lock);
172                 return;
173         }
174
175         fuse_change_attributes_common(inode, attr, attr_valid);
176
177         oldsize = inode->i_size;
178         i_size_write(inode, attr->size);
179         spin_unlock(&fc->lock);
180
181         if (S_ISREG(inode->i_mode) && oldsize != attr->size) {
182                 if (attr->size < oldsize)
183                         fuse_truncate(inode->i_mapping, attr->size);
184                 invalidate_inode_pages2(inode->i_mapping);
185         }
186 }
187
188 static void fuse_init_inode(struct inode *inode, struct fuse_attr *attr)
189 {
190         inode->i_mode = attr->mode & S_IFMT;
191         inode->i_size = attr->size;
192         if (S_ISREG(inode->i_mode)) {
193                 fuse_init_common(inode);
194                 fuse_init_file_inode(inode);
195         } else if (S_ISDIR(inode->i_mode))
196                 fuse_init_dir(inode);
197         else if (S_ISLNK(inode->i_mode))
198                 fuse_init_symlink(inode);
199         else if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode) ||
200                  S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode)) {
201                 fuse_init_common(inode);
202                 init_special_inode(inode, inode->i_mode,
203                                    new_decode_dev(attr->rdev));
204         } else
205                 BUG();
206 }
207
208 static int fuse_inode_eq(struct inode *inode, void *_nodeidp)
209 {
210         u64 nodeid = *(u64 *) _nodeidp;
211         if (get_node_id(inode) == nodeid)
212                 return 1;
213         else
214                 return 0;
215 }
216
217 static int fuse_inode_set(struct inode *inode, void *_nodeidp)
218 {
219         u64 nodeid = *(u64 *) _nodeidp;
220         get_fuse_inode(inode)->nodeid = nodeid;
221         return 0;
222 }
223
224 struct inode *fuse_iget(struct super_block *sb, u64 nodeid,
225                         int generation, struct fuse_attr *attr,
226                         u64 attr_valid, u64 attr_version)
227 {
228         struct inode *inode;
229         struct fuse_inode *fi;
230         struct fuse_conn *fc = get_fuse_conn_super(sb);
231
232  retry:
233         inode = iget5_locked(sb, nodeid, fuse_inode_eq, fuse_inode_set, &nodeid);
234         if (!inode)
235                 return NULL;
236
237         if ((inode->i_state & I_NEW)) {
238                 inode->i_flags |= S_NOATIME|S_NOCMTIME;
239                 inode->i_generation = generation;
240                 inode->i_data.backing_dev_info = &fc->bdi;
241                 fuse_init_inode(inode, attr);
242                 unlock_new_inode(inode);
243         } else if ((inode->i_mode ^ attr->mode) & S_IFMT) {
244                 /* Inode has changed type, any I/O on the old should fail */
245                 make_bad_inode(inode);
246                 iput(inode);
247                 goto retry;
248         }
249
250         fi = get_fuse_inode(inode);
251         spin_lock(&fc->lock);
252         fi->nlookup ++;
253         spin_unlock(&fc->lock);
254         fuse_change_attributes(inode, attr, attr_valid, attr_version);
255
256         return inode;
257 }
258
259 static void fuse_umount_begin(struct super_block *sb)
260 {
261         fuse_abort_conn(get_fuse_conn_super(sb));
262 }
263
264 static void fuse_send_destroy(struct fuse_conn *fc)
265 {
266         struct fuse_req *req = fc->destroy_req;
267         if (req && fc->conn_init) {
268                 fc->destroy_req = NULL;
269                 req->in.h.opcode = FUSE_DESTROY;
270                 req->force = 1;
271                 request_send(fc, req);
272                 fuse_put_request(fc, req);
273         }
274 }
275
276 static void fuse_put_super(struct super_block *sb)
277 {
278         struct fuse_conn *fc = get_fuse_conn_super(sb);
279
280         fuse_send_destroy(fc);
281         spin_lock(&fc->lock);
282         fc->connected = 0;
283         fc->blocked = 0;
284         spin_unlock(&fc->lock);
285         /* Flush all readers on this fs */
286         kill_fasync(&fc->fasync, SIGIO, POLL_IN);
287         wake_up_all(&fc->waitq);
288         wake_up_all(&fc->blocked_waitq);
289         wake_up_all(&fc->reserved_req_waitq);
290         mutex_lock(&fuse_mutex);
291         list_del(&fc->entry);
292         fuse_ctl_remove_conn(fc);
293         mutex_unlock(&fuse_mutex);
294         fuse_conn_put(fc);
295 }
296
297 static void convert_fuse_statfs(struct kstatfs *stbuf, struct fuse_kstatfs *attr)
298 {
299         stbuf->f_type    = FUSE_SUPER_MAGIC;
300         stbuf->f_bsize   = attr->bsize;
301         stbuf->f_frsize  = attr->frsize;
302         stbuf->f_blocks  = attr->blocks;
303         stbuf->f_bfree   = attr->bfree;
304         stbuf->f_bavail  = attr->bavail;
305         stbuf->f_files   = attr->files;
306         stbuf->f_ffree   = attr->ffree;
307         stbuf->f_namelen = attr->namelen;
308         /* fsid is left zero */
309 }
310
311 static int fuse_statfs(struct dentry *dentry, struct kstatfs *buf)
312 {
313         struct super_block *sb = dentry->d_sb;
314         struct fuse_conn *fc = get_fuse_conn_super(sb);
315         struct fuse_req *req;
316         struct fuse_statfs_out outarg;
317         int err;
318
319         if (!fuse_allow_task(fc, current)) {
320                 buf->f_type = FUSE_SUPER_MAGIC;
321                 return 0;
322         }
323
324         req = fuse_get_req(fc);
325         if (IS_ERR(req))
326                 return PTR_ERR(req);
327
328         memset(&outarg, 0, sizeof(outarg));
329         req->in.numargs = 0;
330         req->in.h.opcode = FUSE_STATFS;
331         req->in.h.nodeid = get_node_id(dentry->d_inode);
332         req->out.numargs = 1;
333         req->out.args[0].size =
334                 fc->minor < 4 ? FUSE_COMPAT_STATFS_SIZE : sizeof(outarg);
335         req->out.args[0].value = &outarg;
336         request_send(fc, req);
337         err = req->out.h.error;
338         if (!err)
339                 convert_fuse_statfs(buf, &outarg.st);
340         fuse_put_request(fc, req);
341         return err;
342 }
343
344 enum {
345         OPT_FD,
346         OPT_ROOTMODE,
347         OPT_USER_ID,
348         OPT_GROUP_ID,
349         OPT_DEFAULT_PERMISSIONS,
350         OPT_ALLOW_OTHER,
351         OPT_MAX_READ,
352         OPT_BLKSIZE,
353         OPT_ERR
354 };
355
356 static match_table_t tokens = {
357         {OPT_FD,                        "fd=%u"},
358         {OPT_ROOTMODE,                  "rootmode=%o"},
359         {OPT_USER_ID,                   "user_id=%u"},
360         {OPT_GROUP_ID,                  "group_id=%u"},
361         {OPT_DEFAULT_PERMISSIONS,       "default_permissions"},
362         {OPT_ALLOW_OTHER,               "allow_other"},
363         {OPT_MAX_READ,                  "max_read=%u"},
364         {OPT_BLKSIZE,                   "blksize=%u"},
365         {OPT_ERR,                       NULL}
366 };
367
368 static int parse_fuse_opt(char *opt, struct fuse_mount_data *d, int is_bdev)
369 {
370         char *p;
371         memset(d, 0, sizeof(struct fuse_mount_data));
372         d->max_read = ~0;
373         d->blksize = FUSE_DEFAULT_BLKSIZE;
374
375         while ((p = strsep(&opt, ",")) != NULL) {
376                 int token;
377                 int value;
378                 substring_t args[MAX_OPT_ARGS];
379                 if (!*p)
380                         continue;
381
382                 token = match_token(p, tokens, args);
383                 switch (token) {
384                 case OPT_FD:
385                         if (match_int(&args[0], &value))
386                                 return 0;
387                         d->fd = value;
388                         d->fd_present = 1;
389                         break;
390
391                 case OPT_ROOTMODE:
392                         if (match_octal(&args[0], &value))
393                                 return 0;
394                         if (!fuse_valid_type(value))
395                                 return 0;
396                         d->rootmode = value;
397                         d->rootmode_present = 1;
398                         break;
399
400                 case OPT_USER_ID:
401                         if (match_int(&args[0], &value))
402                                 return 0;
403                         d->user_id = value;
404                         d->user_id_present = 1;
405                         break;
406
407                 case OPT_GROUP_ID:
408                         if (match_int(&args[0], &value))
409                                 return 0;
410                         d->group_id = value;
411                         d->group_id_present = 1;
412                         break;
413
414                 case OPT_DEFAULT_PERMISSIONS:
415                         d->flags |= FUSE_DEFAULT_PERMISSIONS;
416                         break;
417
418                 case OPT_ALLOW_OTHER:
419                         d->flags |= FUSE_ALLOW_OTHER;
420                         break;
421
422                 case OPT_MAX_READ:
423                         if (match_int(&args[0], &value))
424                                 return 0;
425                         d->max_read = value;
426                         break;
427
428                 case OPT_BLKSIZE:
429                         if (!is_bdev || match_int(&args[0], &value))
430                                 return 0;
431                         d->blksize = value;
432                         break;
433
434                 default:
435                         return 0;
436                 }
437         }
438
439         if (!d->fd_present || !d->rootmode_present ||
440             !d->user_id_present || !d->group_id_present)
441                 return 0;
442
443         return 1;
444 }
445
446 static int fuse_show_options(struct seq_file *m, struct vfsmount *mnt)
447 {
448         struct fuse_conn *fc = get_fuse_conn_super(mnt->mnt_sb);
449
450         seq_printf(m, ",user_id=%u", fc->user_id);
451         seq_printf(m, ",group_id=%u", fc->group_id);
452         if (fc->flags & FUSE_DEFAULT_PERMISSIONS)
453                 seq_puts(m, ",default_permissions");
454         if (fc->flags & FUSE_ALLOW_OTHER)
455                 seq_puts(m, ",allow_other");
456         if (fc->max_read != ~0)
457                 seq_printf(m, ",max_read=%u", fc->max_read);
458         if (mnt->mnt_sb->s_bdev &&
459             mnt->mnt_sb->s_blocksize != FUSE_DEFAULT_BLKSIZE)
460                 seq_printf(m, ",blksize=%lu", mnt->mnt_sb->s_blocksize);
461         return 0;
462 }
463
464 static struct fuse_conn *new_conn(struct super_block *sb)
465 {
466         struct fuse_conn *fc;
467         int err;
468
469         fc = kzalloc(sizeof(*fc), GFP_KERNEL);
470         if (fc) {
471                 spin_lock_init(&fc->lock);
472                 mutex_init(&fc->inst_mutex);
473                 atomic_set(&fc->count, 1);
474                 init_waitqueue_head(&fc->waitq);
475                 init_waitqueue_head(&fc->blocked_waitq);
476                 init_waitqueue_head(&fc->reserved_req_waitq);
477                 INIT_LIST_HEAD(&fc->pending);
478                 INIT_LIST_HEAD(&fc->processing);
479                 INIT_LIST_HEAD(&fc->io);
480                 INIT_LIST_HEAD(&fc->interrupts);
481                 INIT_LIST_HEAD(&fc->bg_queue);
482                 atomic_set(&fc->num_waiting, 0);
483                 fc->bdi.ra_pages = (VM_MAX_READAHEAD * 1024) / PAGE_CACHE_SIZE;
484                 fc->bdi.unplug_io_fn = default_unplug_io_fn;
485                 /* fuse does it's own writeback accounting */
486                 fc->bdi.capabilities = BDI_CAP_NO_ACCT_WB;
487                 fc->dev = sb->s_dev;
488                 err = bdi_init(&fc->bdi);
489                 if (err)
490                         goto error_kfree;
491                 err = bdi_register_dev(&fc->bdi, fc->dev);
492                 if (err)
493                         goto error_bdi_destroy;
494                 /*
495                  * For a single fuse filesystem use max 1% of dirty +
496                  * writeback threshold.
497                  *
498                  * This gives about 1M of write buffer for memory maps on a
499                  * machine with 1G and 10% dirty_ratio, which should be more
500                  * than enough.
501                  *
502                  * Privileged users can raise it by writing to
503                  *
504                  *    /sys/class/bdi/<bdi>/max_ratio
505                  */
506                 bdi_set_max_ratio(&fc->bdi, 1);
507                 fc->reqctr = 0;
508                 fc->blocked = 1;
509                 fc->attr_version = 1;
510                 get_random_bytes(&fc->scramble_key, sizeof(fc->scramble_key));
511         }
512         return fc;
513
514 error_bdi_destroy:
515         bdi_destroy(&fc->bdi);
516 error_kfree:
517         mutex_destroy(&fc->inst_mutex);
518         kfree(fc);
519         return NULL;
520 }
521
522 void fuse_conn_put(struct fuse_conn *fc)
523 {
524         if (atomic_dec_and_test(&fc->count)) {
525                 if (fc->destroy_req)
526                         fuse_request_free(fc->destroy_req);
527                 mutex_destroy(&fc->inst_mutex);
528                 bdi_destroy(&fc->bdi);
529                 kfree(fc);
530         }
531 }
532
533 struct fuse_conn *fuse_conn_get(struct fuse_conn *fc)
534 {
535         atomic_inc(&fc->count);
536         return fc;
537 }
538
539 static struct inode *get_root_inode(struct super_block *sb, unsigned mode)
540 {
541         struct fuse_attr attr;
542         memset(&attr, 0, sizeof(attr));
543
544         attr.mode = mode;
545         attr.ino = FUSE_ROOT_ID;
546         attr.nlink = 1;
547         return fuse_iget(sb, 1, 0, &attr, 0, 0);
548 }
549
550 static const struct super_operations fuse_super_operations = {
551         .alloc_inode    = fuse_alloc_inode,
552         .destroy_inode  = fuse_destroy_inode,
553         .clear_inode    = fuse_clear_inode,
554         .drop_inode     = generic_delete_inode,
555         .remount_fs     = fuse_remount_fs,
556         .put_super      = fuse_put_super,
557         .umount_begin   = fuse_umount_begin,
558         .statfs         = fuse_statfs,
559         .show_options   = fuse_show_options,
560 };
561
562 static void process_init_reply(struct fuse_conn *fc, struct fuse_req *req)
563 {
564         struct fuse_init_out *arg = &req->misc.init_out;
565
566         if (req->out.h.error || arg->major != FUSE_KERNEL_VERSION)
567                 fc->conn_error = 1;
568         else {
569                 unsigned long ra_pages;
570
571                 if (arg->minor >= 6) {
572                         ra_pages = arg->max_readahead / PAGE_CACHE_SIZE;
573                         if (arg->flags & FUSE_ASYNC_READ)
574                                 fc->async_read = 1;
575                         if (!(arg->flags & FUSE_POSIX_LOCKS))
576                                 fc->no_lock = 1;
577                         if (arg->flags & FUSE_ATOMIC_O_TRUNC)
578                                 fc->atomic_o_trunc = 1;
579                 } else {
580                         ra_pages = fc->max_read / PAGE_CACHE_SIZE;
581                         fc->no_lock = 1;
582                 }
583
584                 fc->bdi.ra_pages = min(fc->bdi.ra_pages, ra_pages);
585                 fc->minor = arg->minor;
586                 fc->max_write = arg->minor < 5 ? 4096 : arg->max_write;
587                 fc->max_write = min_t(unsigned, 4096, fc->max_write);
588                 fc->conn_init = 1;
589         }
590         fuse_put_request(fc, req);
591         fc->blocked = 0;
592         wake_up_all(&fc->blocked_waitq);
593 }
594
595 static void fuse_send_init(struct fuse_conn *fc, struct fuse_req *req)
596 {
597         struct fuse_init_in *arg = &req->misc.init_in;
598
599         arg->major = FUSE_KERNEL_VERSION;
600         arg->minor = FUSE_KERNEL_MINOR_VERSION;
601         arg->max_readahead = fc->bdi.ra_pages * PAGE_CACHE_SIZE;
602         arg->flags |= FUSE_ASYNC_READ | FUSE_POSIX_LOCKS | FUSE_ATOMIC_O_TRUNC;
603         req->in.h.opcode = FUSE_INIT;
604         req->in.numargs = 1;
605         req->in.args[0].size = sizeof(*arg);
606         req->in.args[0].value = arg;
607         req->out.numargs = 1;
608         /* Variable length arguement used for backward compatibility
609            with interface version < 7.5.  Rest of init_out is zeroed
610            by do_get_request(), so a short reply is not a problem */
611         req->out.argvar = 1;
612         req->out.args[0].size = sizeof(struct fuse_init_out);
613         req->out.args[0].value = &req->misc.init_out;
614         req->end = process_init_reply;
615         request_send_background(fc, req);
616 }
617
618 static int fuse_fill_super(struct super_block *sb, void *data, int silent)
619 {
620         struct fuse_conn *fc;
621         struct inode *root;
622         struct fuse_mount_data d;
623         struct file *file;
624         struct dentry *root_dentry;
625         struct fuse_req *init_req;
626         int err;
627         int is_bdev = sb->s_bdev != NULL;
628
629         if (sb->s_flags & MS_MANDLOCK)
630                 return -EINVAL;
631
632         if (!parse_fuse_opt((char *) data, &d, is_bdev))
633                 return -EINVAL;
634
635         if (is_bdev) {
636 #ifdef CONFIG_BLOCK
637                 if (!sb_set_blocksize(sb, d.blksize))
638                         return -EINVAL;
639 #endif
640         } else {
641                 sb->s_blocksize = PAGE_CACHE_SIZE;
642                 sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
643         }
644         sb->s_magic = FUSE_SUPER_MAGIC;
645         sb->s_op = &fuse_super_operations;
646         sb->s_maxbytes = MAX_LFS_FILESIZE;
647
648         file = fget(d.fd);
649         if (!file)
650                 return -EINVAL;
651
652         if (file->f_op != &fuse_dev_operations)
653                 return -EINVAL;
654
655         fc = new_conn(sb);
656         if (!fc)
657                 return -ENOMEM;
658
659         fc->flags = d.flags;
660         fc->user_id = d.user_id;
661         fc->group_id = d.group_id;
662         fc->max_read = min_t(unsigned, 4096, d.max_read);
663
664         /* Used by get_root_inode() */
665         sb->s_fs_info = fc;
666
667         err = -ENOMEM;
668         root = get_root_inode(sb, d.rootmode);
669         if (!root)
670                 goto err;
671
672         root_dentry = d_alloc_root(root);
673         if (!root_dentry) {
674                 iput(root);
675                 goto err;
676         }
677
678         init_req = fuse_request_alloc();
679         if (!init_req)
680                 goto err_put_root;
681
682         if (is_bdev) {
683                 fc->destroy_req = fuse_request_alloc();
684                 if (!fc->destroy_req)
685                         goto err_put_root;
686         }
687
688         mutex_lock(&fuse_mutex);
689         err = -EINVAL;
690         if (file->private_data)
691                 goto err_unlock;
692
693         err = fuse_ctl_add_conn(fc);
694         if (err)
695                 goto err_unlock;
696
697         list_add_tail(&fc->entry, &fuse_conn_list);
698         sb->s_root = root_dentry;
699         fc->connected = 1;
700         file->private_data = fuse_conn_get(fc);
701         mutex_unlock(&fuse_mutex);
702         /*
703          * atomic_dec_and_test() in fput() provides the necessary
704          * memory barrier for file->private_data to be visible on all
705          * CPUs after this
706          */
707         fput(file);
708
709         fuse_send_init(fc, init_req);
710
711         return 0;
712
713  err_unlock:
714         mutex_unlock(&fuse_mutex);
715         fuse_request_free(init_req);
716  err_put_root:
717         dput(root_dentry);
718  err:
719         fput(file);
720         fuse_conn_put(fc);
721         return err;
722 }
723
724 static int fuse_get_sb(struct file_system_type *fs_type,
725                        int flags, const char *dev_name,
726                        void *raw_data, struct vfsmount *mnt)
727 {
728         return get_sb_nodev(fs_type, flags, raw_data, fuse_fill_super, mnt);
729 }
730
731 static struct file_system_type fuse_fs_type = {
732         .owner          = THIS_MODULE,
733         .name           = "fuse",
734         .fs_flags       = FS_HAS_SUBTYPE,
735         .get_sb         = fuse_get_sb,
736         .kill_sb        = kill_anon_super,
737 };
738
739 #ifdef CONFIG_BLOCK
740 static int fuse_get_sb_blk(struct file_system_type *fs_type,
741                            int flags, const char *dev_name,
742                            void *raw_data, struct vfsmount *mnt)
743 {
744         return get_sb_bdev(fs_type, flags, dev_name, raw_data, fuse_fill_super,
745                            mnt);
746 }
747
748 static struct file_system_type fuseblk_fs_type = {
749         .owner          = THIS_MODULE,
750         .name           = "fuseblk",
751         .get_sb         = fuse_get_sb_blk,
752         .kill_sb        = kill_block_super,
753         .fs_flags       = FS_REQUIRES_DEV | FS_HAS_SUBTYPE,
754 };
755
756 static inline int register_fuseblk(void)
757 {
758         return register_filesystem(&fuseblk_fs_type);
759 }
760
761 static inline void unregister_fuseblk(void)
762 {
763         unregister_filesystem(&fuseblk_fs_type);
764 }
765 #else
766 static inline int register_fuseblk(void)
767 {
768         return 0;
769 }
770
771 static inline void unregister_fuseblk(void)
772 {
773 }
774 #endif
775
776 static void fuse_inode_init_once(struct kmem_cache *cachep, void *foo)
777 {
778         struct inode * inode = foo;
779
780         inode_init_once(inode);
781 }
782
783 static int __init fuse_fs_init(void)
784 {
785         int err;
786
787         err = register_filesystem(&fuse_fs_type);
788         if (err)
789                 goto out;
790
791         err = register_fuseblk();
792         if (err)
793                 goto out_unreg;
794
795         fuse_inode_cachep = kmem_cache_create("fuse_inode",
796                                               sizeof(struct fuse_inode),
797                                               0, SLAB_HWCACHE_ALIGN,
798                                               fuse_inode_init_once);
799         err = -ENOMEM;
800         if (!fuse_inode_cachep)
801                 goto out_unreg2;
802
803         return 0;
804
805  out_unreg2:
806         unregister_fuseblk();
807  out_unreg:
808         unregister_filesystem(&fuse_fs_type);
809  out:
810         return err;
811 }
812
813 static void fuse_fs_cleanup(void)
814 {
815         unregister_filesystem(&fuse_fs_type);
816         unregister_fuseblk();
817         kmem_cache_destroy(fuse_inode_cachep);
818 }
819
820 static struct kobject *fuse_kobj;
821 static struct kobject *connections_kobj;
822
823 static int fuse_sysfs_init(void)
824 {
825         int err;
826
827         fuse_kobj = kobject_create_and_add("fuse", fs_kobj);
828         if (!fuse_kobj) {
829                 err = -ENOMEM;
830                 goto out_err;
831         }
832
833         connections_kobj = kobject_create_and_add("connections", fuse_kobj);
834         if (!connections_kobj) {
835                 err = -ENOMEM;
836                 goto out_fuse_unregister;
837         }
838
839         return 0;
840
841  out_fuse_unregister:
842         kobject_put(fuse_kobj);
843  out_err:
844         return err;
845 }
846
847 static void fuse_sysfs_cleanup(void)
848 {
849         kobject_put(connections_kobj);
850         kobject_put(fuse_kobj);
851 }
852
853 static int __init fuse_init(void)
854 {
855         int res;
856
857         printk("fuse init (API version %i.%i)\n",
858                FUSE_KERNEL_VERSION, FUSE_KERNEL_MINOR_VERSION);
859
860         INIT_LIST_HEAD(&fuse_conn_list);
861         res = fuse_fs_init();
862         if (res)
863                 goto err;
864
865         res = fuse_dev_init();
866         if (res)
867                 goto err_fs_cleanup;
868
869         res = fuse_sysfs_init();
870         if (res)
871                 goto err_dev_cleanup;
872
873         res = fuse_ctl_init();
874         if (res)
875                 goto err_sysfs_cleanup;
876
877         return 0;
878
879  err_sysfs_cleanup:
880         fuse_sysfs_cleanup();
881  err_dev_cleanup:
882         fuse_dev_cleanup();
883  err_fs_cleanup:
884         fuse_fs_cleanup();
885  err:
886         return res;
887 }
888
889 static void __exit fuse_exit(void)
890 {
891         printk(KERN_DEBUG "fuse exit\n");
892
893         fuse_ctl_cleanup();
894         fuse_sysfs_cleanup();
895         fuse_fs_cleanup();
896         fuse_dev_cleanup();
897 }
898
899 module_init(fuse_init);
900 module_exit(fuse_exit);