Add the rt linux 4.1.3-rt3 as base
[kvmfornfv.git] / kernel / fs / fuse / inode.c
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/moduleparam.h>
18 #include <linux/parser.h>
19 #include <linux/statfs.h>
20 #include <linux/random.h>
21 #include <linux/sched.h>
22 #include <linux/exportfs.h>
23
24 MODULE_AUTHOR("Miklos Szeredi <miklos@szeredi.hu>");
25 MODULE_DESCRIPTION("Filesystem in Userspace");
26 MODULE_LICENSE("GPL");
27
28 static struct kmem_cache *fuse_inode_cachep;
29 struct list_head fuse_conn_list;
30 DEFINE_MUTEX(fuse_mutex);
31
32 static int set_global_limit(const char *val, struct kernel_param *kp);
33
34 unsigned max_user_bgreq;
35 module_param_call(max_user_bgreq, set_global_limit, param_get_uint,
36                   &max_user_bgreq, 0644);
37 __MODULE_PARM_TYPE(max_user_bgreq, "uint");
38 MODULE_PARM_DESC(max_user_bgreq,
39  "Global limit for the maximum number of backgrounded requests an "
40  "unprivileged user can set");
41
42 unsigned max_user_congthresh;
43 module_param_call(max_user_congthresh, set_global_limit, param_get_uint,
44                   &max_user_congthresh, 0644);
45 __MODULE_PARM_TYPE(max_user_congthresh, "uint");
46 MODULE_PARM_DESC(max_user_congthresh,
47  "Global limit for the maximum congestion threshold an "
48  "unprivileged user can set");
49
50 #define FUSE_SUPER_MAGIC 0x65735546
51
52 #define FUSE_DEFAULT_BLKSIZE 512
53
54 /** Maximum number of outstanding background requests */
55 #define FUSE_DEFAULT_MAX_BACKGROUND 12
56
57 /** Congestion starts at 75% of maximum */
58 #define FUSE_DEFAULT_CONGESTION_THRESHOLD (FUSE_DEFAULT_MAX_BACKGROUND * 3 / 4)
59
60 struct fuse_mount_data {
61         int fd;
62         unsigned rootmode;
63         kuid_t user_id;
64         kgid_t group_id;
65         unsigned fd_present:1;
66         unsigned rootmode_present:1;
67         unsigned user_id_present:1;
68         unsigned group_id_present:1;
69         unsigned flags;
70         unsigned max_read;
71         unsigned blksize;
72 };
73
74 struct fuse_forget_link *fuse_alloc_forget(void)
75 {
76         return kzalloc(sizeof(struct fuse_forget_link), GFP_KERNEL);
77 }
78
79 static struct inode *fuse_alloc_inode(struct super_block *sb)
80 {
81         struct inode *inode;
82         struct fuse_inode *fi;
83
84         inode = kmem_cache_alloc(fuse_inode_cachep, GFP_KERNEL);
85         if (!inode)
86                 return NULL;
87
88         fi = get_fuse_inode(inode);
89         fi->i_time = 0;
90         fi->nodeid = 0;
91         fi->nlookup = 0;
92         fi->attr_version = 0;
93         fi->writectr = 0;
94         fi->orig_ino = 0;
95         fi->state = 0;
96         INIT_LIST_HEAD(&fi->write_files);
97         INIT_LIST_HEAD(&fi->queued_writes);
98         INIT_LIST_HEAD(&fi->writepages);
99         init_waitqueue_head(&fi->page_waitq);
100         fi->forget = fuse_alloc_forget();
101         if (!fi->forget) {
102                 kmem_cache_free(fuse_inode_cachep, inode);
103                 return NULL;
104         }
105
106         return inode;
107 }
108
109 static void fuse_i_callback(struct rcu_head *head)
110 {
111         struct inode *inode = container_of(head, struct inode, i_rcu);
112         kmem_cache_free(fuse_inode_cachep, inode);
113 }
114
115 static void fuse_destroy_inode(struct inode *inode)
116 {
117         struct fuse_inode *fi = get_fuse_inode(inode);
118         BUG_ON(!list_empty(&fi->write_files));
119         BUG_ON(!list_empty(&fi->queued_writes));
120         kfree(fi->forget);
121         call_rcu(&inode->i_rcu, fuse_i_callback);
122 }
123
124 static void fuse_evict_inode(struct inode *inode)
125 {
126         truncate_inode_pages_final(&inode->i_data);
127         clear_inode(inode);
128         if (inode->i_sb->s_flags & MS_ACTIVE) {
129                 struct fuse_conn *fc = get_fuse_conn(inode);
130                 struct fuse_inode *fi = get_fuse_inode(inode);
131                 fuse_queue_forget(fc, fi->forget, fi->nodeid, fi->nlookup);
132                 fi->forget = NULL;
133         }
134 }
135
136 static int fuse_remount_fs(struct super_block *sb, int *flags, char *data)
137 {
138         sync_filesystem(sb);
139         if (*flags & MS_MANDLOCK)
140                 return -EINVAL;
141
142         return 0;
143 }
144
145 /*
146  * ino_t is 32-bits on 32-bit arch. We have to squash the 64-bit value down
147  * so that it will fit.
148  */
149 static ino_t fuse_squash_ino(u64 ino64)
150 {
151         ino_t ino = (ino_t) ino64;
152         if (sizeof(ino_t) < sizeof(u64))
153                 ino ^= ino64 >> (sizeof(u64) - sizeof(ino_t)) * 8;
154         return ino;
155 }
156
157 void fuse_change_attributes_common(struct inode *inode, struct fuse_attr *attr,
158                                    u64 attr_valid)
159 {
160         struct fuse_conn *fc = get_fuse_conn(inode);
161         struct fuse_inode *fi = get_fuse_inode(inode);
162
163         fi->attr_version = ++fc->attr_version;
164         fi->i_time = attr_valid;
165
166         inode->i_ino     = fuse_squash_ino(attr->ino);
167         inode->i_mode    = (inode->i_mode & S_IFMT) | (attr->mode & 07777);
168         set_nlink(inode, attr->nlink);
169         inode->i_uid     = make_kuid(&init_user_ns, attr->uid);
170         inode->i_gid     = make_kgid(&init_user_ns, attr->gid);
171         inode->i_blocks  = attr->blocks;
172         inode->i_atime.tv_sec   = attr->atime;
173         inode->i_atime.tv_nsec  = attr->atimensec;
174         /* mtime from server may be stale due to local buffered write */
175         if (!fc->writeback_cache || !S_ISREG(inode->i_mode)) {
176                 inode->i_mtime.tv_sec   = attr->mtime;
177                 inode->i_mtime.tv_nsec  = attr->mtimensec;
178                 inode->i_ctime.tv_sec   = attr->ctime;
179                 inode->i_ctime.tv_nsec  = attr->ctimensec;
180         }
181
182         if (attr->blksize != 0)
183                 inode->i_blkbits = ilog2(attr->blksize);
184         else
185                 inode->i_blkbits = inode->i_sb->s_blocksize_bits;
186
187         /*
188          * Don't set the sticky bit in i_mode, unless we want the VFS
189          * to check permissions.  This prevents failures due to the
190          * check in may_delete().
191          */
192         fi->orig_i_mode = inode->i_mode;
193         if (!(fc->flags & FUSE_DEFAULT_PERMISSIONS))
194                 inode->i_mode &= ~S_ISVTX;
195
196         fi->orig_ino = attr->ino;
197 }
198
199 void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr,
200                             u64 attr_valid, u64 attr_version)
201 {
202         struct fuse_conn *fc = get_fuse_conn(inode);
203         struct fuse_inode *fi = get_fuse_inode(inode);
204         bool is_wb = fc->writeback_cache;
205         loff_t oldsize;
206         struct timespec old_mtime;
207
208         spin_lock(&fc->lock);
209         if ((attr_version != 0 && fi->attr_version > attr_version) ||
210             test_bit(FUSE_I_SIZE_UNSTABLE, &fi->state)) {
211                 spin_unlock(&fc->lock);
212                 return;
213         }
214
215         old_mtime = inode->i_mtime;
216         fuse_change_attributes_common(inode, attr, attr_valid);
217
218         oldsize = inode->i_size;
219         /*
220          * In case of writeback_cache enabled, the cached writes beyond EOF
221          * extend local i_size without keeping userspace server in sync. So,
222          * attr->size coming from server can be stale. We cannot trust it.
223          */
224         if (!is_wb || !S_ISREG(inode->i_mode))
225                 i_size_write(inode, attr->size);
226         spin_unlock(&fc->lock);
227
228         if (!is_wb && S_ISREG(inode->i_mode)) {
229                 bool inval = false;
230
231                 if (oldsize != attr->size) {
232                         truncate_pagecache(inode, attr->size);
233                         inval = true;
234                 } else if (fc->auto_inval_data) {
235                         struct timespec new_mtime = {
236                                 .tv_sec = attr->mtime,
237                                 .tv_nsec = attr->mtimensec,
238                         };
239
240                         /*
241                          * Auto inval mode also checks and invalidates if mtime
242                          * has changed.
243                          */
244                         if (!timespec_equal(&old_mtime, &new_mtime))
245                                 inval = true;
246                 }
247
248                 if (inval)
249                         invalidate_inode_pages2(inode->i_mapping);
250         }
251 }
252
253 static void fuse_init_inode(struct inode *inode, struct fuse_attr *attr)
254 {
255         inode->i_mode = attr->mode & S_IFMT;
256         inode->i_size = attr->size;
257         inode->i_mtime.tv_sec  = attr->mtime;
258         inode->i_mtime.tv_nsec = attr->mtimensec;
259         inode->i_ctime.tv_sec  = attr->ctime;
260         inode->i_ctime.tv_nsec = attr->ctimensec;
261         if (S_ISREG(inode->i_mode)) {
262                 fuse_init_common(inode);
263                 fuse_init_file_inode(inode);
264         } else if (S_ISDIR(inode->i_mode))
265                 fuse_init_dir(inode);
266         else if (S_ISLNK(inode->i_mode))
267                 fuse_init_symlink(inode);
268         else if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode) ||
269                  S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode)) {
270                 fuse_init_common(inode);
271                 init_special_inode(inode, inode->i_mode,
272                                    new_decode_dev(attr->rdev));
273         } else
274                 BUG();
275 }
276
277 int fuse_inode_eq(struct inode *inode, void *_nodeidp)
278 {
279         u64 nodeid = *(u64 *) _nodeidp;
280         if (get_node_id(inode) == nodeid)
281                 return 1;
282         else
283                 return 0;
284 }
285
286 static int fuse_inode_set(struct inode *inode, void *_nodeidp)
287 {
288         u64 nodeid = *(u64 *) _nodeidp;
289         get_fuse_inode(inode)->nodeid = nodeid;
290         return 0;
291 }
292
293 struct inode *fuse_iget(struct super_block *sb, u64 nodeid,
294                         int generation, struct fuse_attr *attr,
295                         u64 attr_valid, u64 attr_version)
296 {
297         struct inode *inode;
298         struct fuse_inode *fi;
299         struct fuse_conn *fc = get_fuse_conn_super(sb);
300
301  retry:
302         inode = iget5_locked(sb, nodeid, fuse_inode_eq, fuse_inode_set, &nodeid);
303         if (!inode)
304                 return NULL;
305
306         if ((inode->i_state & I_NEW)) {
307                 inode->i_flags |= S_NOATIME;
308                 if (!fc->writeback_cache || !S_ISREG(attr->mode))
309                         inode->i_flags |= S_NOCMTIME;
310                 inode->i_generation = generation;
311                 fuse_init_inode(inode, attr);
312                 unlock_new_inode(inode);
313         } else if ((inode->i_mode ^ attr->mode) & S_IFMT) {
314                 /* Inode has changed type, any I/O on the old should fail */
315                 make_bad_inode(inode);
316                 iput(inode);
317                 goto retry;
318         }
319
320         fi = get_fuse_inode(inode);
321         spin_lock(&fc->lock);
322         fi->nlookup++;
323         spin_unlock(&fc->lock);
324         fuse_change_attributes(inode, attr, attr_valid, attr_version);
325
326         return inode;
327 }
328
329 int fuse_reverse_inval_inode(struct super_block *sb, u64 nodeid,
330                              loff_t offset, loff_t len)
331 {
332         struct inode *inode;
333         pgoff_t pg_start;
334         pgoff_t pg_end;
335
336         inode = ilookup5(sb, nodeid, fuse_inode_eq, &nodeid);
337         if (!inode)
338                 return -ENOENT;
339
340         fuse_invalidate_attr(inode);
341         if (offset >= 0) {
342                 pg_start = offset >> PAGE_CACHE_SHIFT;
343                 if (len <= 0)
344                         pg_end = -1;
345                 else
346                         pg_end = (offset + len - 1) >> PAGE_CACHE_SHIFT;
347                 invalidate_inode_pages2_range(inode->i_mapping,
348                                               pg_start, pg_end);
349         }
350         iput(inode);
351         return 0;
352 }
353
354 static void fuse_umount_begin(struct super_block *sb)
355 {
356         fuse_abort_conn(get_fuse_conn_super(sb));
357 }
358
359 static void fuse_send_destroy(struct fuse_conn *fc)
360 {
361         struct fuse_req *req = fc->destroy_req;
362         if (req && fc->conn_init) {
363                 fc->destroy_req = NULL;
364                 req->in.h.opcode = FUSE_DESTROY;
365                 req->force = 1;
366                 req->background = 0;
367                 fuse_request_send(fc, req);
368                 fuse_put_request(fc, req);
369         }
370 }
371
372 static void fuse_bdi_destroy(struct fuse_conn *fc)
373 {
374         if (fc->bdi_initialized)
375                 bdi_destroy(&fc->bdi);
376 }
377
378 static void fuse_put_super(struct super_block *sb)
379 {
380         struct fuse_conn *fc = get_fuse_conn_super(sb);
381
382         fuse_send_destroy(fc);
383
384         fuse_abort_conn(fc);
385         mutex_lock(&fuse_mutex);
386         list_del(&fc->entry);
387         fuse_ctl_remove_conn(fc);
388         mutex_unlock(&fuse_mutex);
389         fuse_bdi_destroy(fc);
390
391         fuse_conn_put(fc);
392 }
393
394 static void convert_fuse_statfs(struct kstatfs *stbuf, struct fuse_kstatfs *attr)
395 {
396         stbuf->f_type    = FUSE_SUPER_MAGIC;
397         stbuf->f_bsize   = attr->bsize;
398         stbuf->f_frsize  = attr->frsize;
399         stbuf->f_blocks  = attr->blocks;
400         stbuf->f_bfree   = attr->bfree;
401         stbuf->f_bavail  = attr->bavail;
402         stbuf->f_files   = attr->files;
403         stbuf->f_ffree   = attr->ffree;
404         stbuf->f_namelen = attr->namelen;
405         /* fsid is left zero */
406 }
407
408 static int fuse_statfs(struct dentry *dentry, struct kstatfs *buf)
409 {
410         struct super_block *sb = dentry->d_sb;
411         struct fuse_conn *fc = get_fuse_conn_super(sb);
412         FUSE_ARGS(args);
413         struct fuse_statfs_out outarg;
414         int err;
415
416         if (!fuse_allow_current_process(fc)) {
417                 buf->f_type = FUSE_SUPER_MAGIC;
418                 return 0;
419         }
420
421         memset(&outarg, 0, sizeof(outarg));
422         args.in.numargs = 0;
423         args.in.h.opcode = FUSE_STATFS;
424         args.in.h.nodeid = get_node_id(d_inode(dentry));
425         args.out.numargs = 1;
426         args.out.args[0].size = sizeof(outarg);
427         args.out.args[0].value = &outarg;
428         err = fuse_simple_request(fc, &args);
429         if (!err)
430                 convert_fuse_statfs(buf, &outarg.st);
431         return err;
432 }
433
434 enum {
435         OPT_FD,
436         OPT_ROOTMODE,
437         OPT_USER_ID,
438         OPT_GROUP_ID,
439         OPT_DEFAULT_PERMISSIONS,
440         OPT_ALLOW_OTHER,
441         OPT_MAX_READ,
442         OPT_BLKSIZE,
443         OPT_ERR
444 };
445
446 static const match_table_t tokens = {
447         {OPT_FD,                        "fd=%u"},
448         {OPT_ROOTMODE,                  "rootmode=%o"},
449         {OPT_USER_ID,                   "user_id=%u"},
450         {OPT_GROUP_ID,                  "group_id=%u"},
451         {OPT_DEFAULT_PERMISSIONS,       "default_permissions"},
452         {OPT_ALLOW_OTHER,               "allow_other"},
453         {OPT_MAX_READ,                  "max_read=%u"},
454         {OPT_BLKSIZE,                   "blksize=%u"},
455         {OPT_ERR,                       NULL}
456 };
457
458 static int fuse_match_uint(substring_t *s, unsigned int *res)
459 {
460         int err = -ENOMEM;
461         char *buf = match_strdup(s);
462         if (buf) {
463                 err = kstrtouint(buf, 10, res);
464                 kfree(buf);
465         }
466         return err;
467 }
468
469 static int parse_fuse_opt(char *opt, struct fuse_mount_data *d, int is_bdev)
470 {
471         char *p;
472         memset(d, 0, sizeof(struct fuse_mount_data));
473         d->max_read = ~0;
474         d->blksize = FUSE_DEFAULT_BLKSIZE;
475
476         while ((p = strsep(&opt, ",")) != NULL) {
477                 int token;
478                 int value;
479                 unsigned uv;
480                 substring_t args[MAX_OPT_ARGS];
481                 if (!*p)
482                         continue;
483
484                 token = match_token(p, tokens, args);
485                 switch (token) {
486                 case OPT_FD:
487                         if (match_int(&args[0], &value))
488                                 return 0;
489                         d->fd = value;
490                         d->fd_present = 1;
491                         break;
492
493                 case OPT_ROOTMODE:
494                         if (match_octal(&args[0], &value))
495                                 return 0;
496                         if (!fuse_valid_type(value))
497                                 return 0;
498                         d->rootmode = value;
499                         d->rootmode_present = 1;
500                         break;
501
502                 case OPT_USER_ID:
503                         if (fuse_match_uint(&args[0], &uv))
504                                 return 0;
505                         d->user_id = make_kuid(current_user_ns(), uv);
506                         if (!uid_valid(d->user_id))
507                                 return 0;
508                         d->user_id_present = 1;
509                         break;
510
511                 case OPT_GROUP_ID:
512                         if (fuse_match_uint(&args[0], &uv))
513                                 return 0;
514                         d->group_id = make_kgid(current_user_ns(), uv);
515                         if (!gid_valid(d->group_id))
516                                 return 0;
517                         d->group_id_present = 1;
518                         break;
519
520                 case OPT_DEFAULT_PERMISSIONS:
521                         d->flags |= FUSE_DEFAULT_PERMISSIONS;
522                         break;
523
524                 case OPT_ALLOW_OTHER:
525                         d->flags |= FUSE_ALLOW_OTHER;
526                         break;
527
528                 case OPT_MAX_READ:
529                         if (match_int(&args[0], &value))
530                                 return 0;
531                         d->max_read = value;
532                         break;
533
534                 case OPT_BLKSIZE:
535                         if (!is_bdev || match_int(&args[0], &value))
536                                 return 0;
537                         d->blksize = value;
538                         break;
539
540                 default:
541                         return 0;
542                 }
543         }
544
545         if (!d->fd_present || !d->rootmode_present ||
546             !d->user_id_present || !d->group_id_present)
547                 return 0;
548
549         return 1;
550 }
551
552 static int fuse_show_options(struct seq_file *m, struct dentry *root)
553 {
554         struct super_block *sb = root->d_sb;
555         struct fuse_conn *fc = get_fuse_conn_super(sb);
556
557         seq_printf(m, ",user_id=%u", from_kuid_munged(&init_user_ns, fc->user_id));
558         seq_printf(m, ",group_id=%u", from_kgid_munged(&init_user_ns, fc->group_id));
559         if (fc->flags & FUSE_DEFAULT_PERMISSIONS)
560                 seq_puts(m, ",default_permissions");
561         if (fc->flags & FUSE_ALLOW_OTHER)
562                 seq_puts(m, ",allow_other");
563         if (fc->max_read != ~0)
564                 seq_printf(m, ",max_read=%u", fc->max_read);
565         if (sb->s_bdev && sb->s_blocksize != FUSE_DEFAULT_BLKSIZE)
566                 seq_printf(m, ",blksize=%lu", sb->s_blocksize);
567         return 0;
568 }
569
570 void fuse_conn_init(struct fuse_conn *fc)
571 {
572         memset(fc, 0, sizeof(*fc));
573         spin_lock_init(&fc->lock);
574         init_rwsem(&fc->killsb);
575         atomic_set(&fc->count, 1);
576         init_waitqueue_head(&fc->waitq);
577         init_waitqueue_head(&fc->blocked_waitq);
578         init_waitqueue_head(&fc->reserved_req_waitq);
579         INIT_LIST_HEAD(&fc->pending);
580         INIT_LIST_HEAD(&fc->processing);
581         INIT_LIST_HEAD(&fc->io);
582         INIT_LIST_HEAD(&fc->interrupts);
583         INIT_LIST_HEAD(&fc->bg_queue);
584         INIT_LIST_HEAD(&fc->entry);
585         fc->forget_list_tail = &fc->forget_list_head;
586         atomic_set(&fc->num_waiting, 0);
587         fc->max_background = FUSE_DEFAULT_MAX_BACKGROUND;
588         fc->congestion_threshold = FUSE_DEFAULT_CONGESTION_THRESHOLD;
589         fc->khctr = 0;
590         fc->polled_files = RB_ROOT;
591         fc->reqctr = 0;
592         fc->blocked = 0;
593         fc->initialized = 0;
594         fc->attr_version = 1;
595         get_random_bytes(&fc->scramble_key, sizeof(fc->scramble_key));
596 }
597 EXPORT_SYMBOL_GPL(fuse_conn_init);
598
599 void fuse_conn_put(struct fuse_conn *fc)
600 {
601         if (atomic_dec_and_test(&fc->count)) {
602                 if (fc->destroy_req)
603                         fuse_request_free(fc->destroy_req);
604                 fc->release(fc);
605         }
606 }
607 EXPORT_SYMBOL_GPL(fuse_conn_put);
608
609 struct fuse_conn *fuse_conn_get(struct fuse_conn *fc)
610 {
611         atomic_inc(&fc->count);
612         return fc;
613 }
614 EXPORT_SYMBOL_GPL(fuse_conn_get);
615
616 static struct inode *fuse_get_root_inode(struct super_block *sb, unsigned mode)
617 {
618         struct fuse_attr attr;
619         memset(&attr, 0, sizeof(attr));
620
621         attr.mode = mode;
622         attr.ino = FUSE_ROOT_ID;
623         attr.nlink = 1;
624         return fuse_iget(sb, 1, 0, &attr, 0, 0);
625 }
626
627 struct fuse_inode_handle {
628         u64 nodeid;
629         u32 generation;
630 };
631
632 static struct dentry *fuse_get_dentry(struct super_block *sb,
633                                       struct fuse_inode_handle *handle)
634 {
635         struct fuse_conn *fc = get_fuse_conn_super(sb);
636         struct inode *inode;
637         struct dentry *entry;
638         int err = -ESTALE;
639
640         if (handle->nodeid == 0)
641                 goto out_err;
642
643         inode = ilookup5(sb, handle->nodeid, fuse_inode_eq, &handle->nodeid);
644         if (!inode) {
645                 struct fuse_entry_out outarg;
646                 struct qstr name;
647
648                 if (!fc->export_support)
649                         goto out_err;
650
651                 name.len = 1;
652                 name.name = ".";
653                 err = fuse_lookup_name(sb, handle->nodeid, &name, &outarg,
654                                        &inode);
655                 if (err && err != -ENOENT)
656                         goto out_err;
657                 if (err || !inode) {
658                         err = -ESTALE;
659                         goto out_err;
660                 }
661                 err = -EIO;
662                 if (get_node_id(inode) != handle->nodeid)
663                         goto out_iput;
664         }
665         err = -ESTALE;
666         if (inode->i_generation != handle->generation)
667                 goto out_iput;
668
669         entry = d_obtain_alias(inode);
670         if (!IS_ERR(entry) && get_node_id(inode) != FUSE_ROOT_ID)
671                 fuse_invalidate_entry_cache(entry);
672
673         return entry;
674
675  out_iput:
676         iput(inode);
677  out_err:
678         return ERR_PTR(err);
679 }
680
681 static int fuse_encode_fh(struct inode *inode, u32 *fh, int *max_len,
682                            struct inode *parent)
683 {
684         int len = parent ? 6 : 3;
685         u64 nodeid;
686         u32 generation;
687
688         if (*max_len < len) {
689                 *max_len = len;
690                 return  FILEID_INVALID;
691         }
692
693         nodeid = get_fuse_inode(inode)->nodeid;
694         generation = inode->i_generation;
695
696         fh[0] = (u32)(nodeid >> 32);
697         fh[1] = (u32)(nodeid & 0xffffffff);
698         fh[2] = generation;
699
700         if (parent) {
701                 nodeid = get_fuse_inode(parent)->nodeid;
702                 generation = parent->i_generation;
703
704                 fh[3] = (u32)(nodeid >> 32);
705                 fh[4] = (u32)(nodeid & 0xffffffff);
706                 fh[5] = generation;
707         }
708
709         *max_len = len;
710         return parent ? 0x82 : 0x81;
711 }
712
713 static struct dentry *fuse_fh_to_dentry(struct super_block *sb,
714                 struct fid *fid, int fh_len, int fh_type)
715 {
716         struct fuse_inode_handle handle;
717
718         if ((fh_type != 0x81 && fh_type != 0x82) || fh_len < 3)
719                 return NULL;
720
721         handle.nodeid = (u64) fid->raw[0] << 32;
722         handle.nodeid |= (u64) fid->raw[1];
723         handle.generation = fid->raw[2];
724         return fuse_get_dentry(sb, &handle);
725 }
726
727 static struct dentry *fuse_fh_to_parent(struct super_block *sb,
728                 struct fid *fid, int fh_len, int fh_type)
729 {
730         struct fuse_inode_handle parent;
731
732         if (fh_type != 0x82 || fh_len < 6)
733                 return NULL;
734
735         parent.nodeid = (u64) fid->raw[3] << 32;
736         parent.nodeid |= (u64) fid->raw[4];
737         parent.generation = fid->raw[5];
738         return fuse_get_dentry(sb, &parent);
739 }
740
741 static struct dentry *fuse_get_parent(struct dentry *child)
742 {
743         struct inode *child_inode = d_inode(child);
744         struct fuse_conn *fc = get_fuse_conn(child_inode);
745         struct inode *inode;
746         struct dentry *parent;
747         struct fuse_entry_out outarg;
748         struct qstr name;
749         int err;
750
751         if (!fc->export_support)
752                 return ERR_PTR(-ESTALE);
753
754         name.len = 2;
755         name.name = "..";
756         err = fuse_lookup_name(child_inode->i_sb, get_node_id(child_inode),
757                                &name, &outarg, &inode);
758         if (err) {
759                 if (err == -ENOENT)
760                         return ERR_PTR(-ESTALE);
761                 return ERR_PTR(err);
762         }
763
764         parent = d_obtain_alias(inode);
765         if (!IS_ERR(parent) && get_node_id(inode) != FUSE_ROOT_ID)
766                 fuse_invalidate_entry_cache(parent);
767
768         return parent;
769 }
770
771 static const struct export_operations fuse_export_operations = {
772         .fh_to_dentry   = fuse_fh_to_dentry,
773         .fh_to_parent   = fuse_fh_to_parent,
774         .encode_fh      = fuse_encode_fh,
775         .get_parent     = fuse_get_parent,
776 };
777
778 static const struct super_operations fuse_super_operations = {
779         .alloc_inode    = fuse_alloc_inode,
780         .destroy_inode  = fuse_destroy_inode,
781         .evict_inode    = fuse_evict_inode,
782         .write_inode    = fuse_write_inode,
783         .drop_inode     = generic_delete_inode,
784         .remount_fs     = fuse_remount_fs,
785         .put_super      = fuse_put_super,
786         .umount_begin   = fuse_umount_begin,
787         .statfs         = fuse_statfs,
788         .show_options   = fuse_show_options,
789 };
790
791 static void sanitize_global_limit(unsigned *limit)
792 {
793         if (*limit == 0)
794                 *limit = ((totalram_pages << PAGE_SHIFT) >> 13) /
795                          sizeof(struct fuse_req);
796
797         if (*limit >= 1 << 16)
798                 *limit = (1 << 16) - 1;
799 }
800
801 static int set_global_limit(const char *val, struct kernel_param *kp)
802 {
803         int rv;
804
805         rv = param_set_uint(val, kp);
806         if (rv)
807                 return rv;
808
809         sanitize_global_limit((unsigned *)kp->arg);
810
811         return 0;
812 }
813
814 static void process_init_limits(struct fuse_conn *fc, struct fuse_init_out *arg)
815 {
816         int cap_sys_admin = capable(CAP_SYS_ADMIN);
817
818         if (arg->minor < 13)
819                 return;
820
821         sanitize_global_limit(&max_user_bgreq);
822         sanitize_global_limit(&max_user_congthresh);
823
824         if (arg->max_background) {
825                 fc->max_background = arg->max_background;
826
827                 if (!cap_sys_admin && fc->max_background > max_user_bgreq)
828                         fc->max_background = max_user_bgreq;
829         }
830         if (arg->congestion_threshold) {
831                 fc->congestion_threshold = arg->congestion_threshold;
832
833                 if (!cap_sys_admin &&
834                     fc->congestion_threshold > max_user_congthresh)
835                         fc->congestion_threshold = max_user_congthresh;
836         }
837 }
838
839 static void process_init_reply(struct fuse_conn *fc, struct fuse_req *req)
840 {
841         struct fuse_init_out *arg = &req->misc.init_out;
842
843         if (req->out.h.error || arg->major != FUSE_KERNEL_VERSION)
844                 fc->conn_error = 1;
845         else {
846                 unsigned long ra_pages;
847
848                 process_init_limits(fc, arg);
849
850                 if (arg->minor >= 6) {
851                         ra_pages = arg->max_readahead / PAGE_CACHE_SIZE;
852                         if (arg->flags & FUSE_ASYNC_READ)
853                                 fc->async_read = 1;
854                         if (!(arg->flags & FUSE_POSIX_LOCKS))
855                                 fc->no_lock = 1;
856                         if (arg->minor >= 17) {
857                                 if (!(arg->flags & FUSE_FLOCK_LOCKS))
858                                         fc->no_flock = 1;
859                         } else {
860                                 if (!(arg->flags & FUSE_POSIX_LOCKS))
861                                         fc->no_flock = 1;
862                         }
863                         if (arg->flags & FUSE_ATOMIC_O_TRUNC)
864                                 fc->atomic_o_trunc = 1;
865                         if (arg->minor >= 9) {
866                                 /* LOOKUP has dependency on proto version */
867                                 if (arg->flags & FUSE_EXPORT_SUPPORT)
868                                         fc->export_support = 1;
869                         }
870                         if (arg->flags & FUSE_BIG_WRITES)
871                                 fc->big_writes = 1;
872                         if (arg->flags & FUSE_DONT_MASK)
873                                 fc->dont_mask = 1;
874                         if (arg->flags & FUSE_AUTO_INVAL_DATA)
875                                 fc->auto_inval_data = 1;
876                         if (arg->flags & FUSE_DO_READDIRPLUS) {
877                                 fc->do_readdirplus = 1;
878                                 if (arg->flags & FUSE_READDIRPLUS_AUTO)
879                                         fc->readdirplus_auto = 1;
880                         }
881                         if (arg->flags & FUSE_ASYNC_DIO)
882                                 fc->async_dio = 1;
883                         if (arg->flags & FUSE_WRITEBACK_CACHE)
884                                 fc->writeback_cache = 1;
885                         if (arg->time_gran && arg->time_gran <= 1000000000)
886                                 fc->sb->s_time_gran = arg->time_gran;
887                 } else {
888                         ra_pages = fc->max_read / PAGE_CACHE_SIZE;
889                         fc->no_lock = 1;
890                         fc->no_flock = 1;
891                 }
892
893                 fc->bdi.ra_pages = min(fc->bdi.ra_pages, ra_pages);
894                 fc->minor = arg->minor;
895                 fc->max_write = arg->minor < 5 ? 4096 : arg->max_write;
896                 fc->max_write = max_t(unsigned, 4096, fc->max_write);
897                 fc->conn_init = 1;
898         }
899         fuse_set_initialized(fc);
900         wake_up_all(&fc->blocked_waitq);
901 }
902
903 static void fuse_send_init(struct fuse_conn *fc, struct fuse_req *req)
904 {
905         struct fuse_init_in *arg = &req->misc.init_in;
906
907         arg->major = FUSE_KERNEL_VERSION;
908         arg->minor = FUSE_KERNEL_MINOR_VERSION;
909         arg->max_readahead = fc->bdi.ra_pages * PAGE_CACHE_SIZE;
910         arg->flags |= FUSE_ASYNC_READ | FUSE_POSIX_LOCKS | FUSE_ATOMIC_O_TRUNC |
911                 FUSE_EXPORT_SUPPORT | FUSE_BIG_WRITES | FUSE_DONT_MASK |
912                 FUSE_SPLICE_WRITE | FUSE_SPLICE_MOVE | FUSE_SPLICE_READ |
913                 FUSE_FLOCK_LOCKS | FUSE_IOCTL_DIR | FUSE_AUTO_INVAL_DATA |
914                 FUSE_DO_READDIRPLUS | FUSE_READDIRPLUS_AUTO | FUSE_ASYNC_DIO |
915                 FUSE_WRITEBACK_CACHE | FUSE_NO_OPEN_SUPPORT;
916         req->in.h.opcode = FUSE_INIT;
917         req->in.numargs = 1;
918         req->in.args[0].size = sizeof(*arg);
919         req->in.args[0].value = arg;
920         req->out.numargs = 1;
921         /* Variable length argument used for backward compatibility
922            with interface version < 7.5.  Rest of init_out is zeroed
923            by do_get_request(), so a short reply is not a problem */
924         req->out.argvar = 1;
925         req->out.args[0].size = sizeof(struct fuse_init_out);
926         req->out.args[0].value = &req->misc.init_out;
927         req->end = process_init_reply;
928         fuse_request_send_background(fc, req);
929 }
930
931 static void fuse_free_conn(struct fuse_conn *fc)
932 {
933         kfree_rcu(fc, rcu);
934 }
935
936 static int fuse_bdi_init(struct fuse_conn *fc, struct super_block *sb)
937 {
938         int err;
939
940         fc->bdi.name = "fuse";
941         fc->bdi.ra_pages = (VM_MAX_READAHEAD * 1024) / PAGE_CACHE_SIZE;
942         /* fuse does it's own writeback accounting */
943         fc->bdi.capabilities = BDI_CAP_NO_ACCT_WB | BDI_CAP_STRICTLIMIT;
944
945         err = bdi_init(&fc->bdi);
946         if (err)
947                 return err;
948
949         fc->bdi_initialized = 1;
950
951         if (sb->s_bdev) {
952                 err =  bdi_register(&fc->bdi, NULL, "%u:%u-fuseblk",
953                                     MAJOR(fc->dev), MINOR(fc->dev));
954         } else {
955                 err = bdi_register_dev(&fc->bdi, fc->dev);
956         }
957
958         if (err)
959                 return err;
960
961         /*
962          * For a single fuse filesystem use max 1% of dirty +
963          * writeback threshold.
964          *
965          * This gives about 1M of write buffer for memory maps on a
966          * machine with 1G and 10% dirty_ratio, which should be more
967          * than enough.
968          *
969          * Privileged users can raise it by writing to
970          *
971          *    /sys/class/bdi/<bdi>/max_ratio
972          */
973         bdi_set_max_ratio(&fc->bdi, 1);
974
975         return 0;
976 }
977
978 static int fuse_fill_super(struct super_block *sb, void *data, int silent)
979 {
980         struct fuse_conn *fc;
981         struct inode *root;
982         struct fuse_mount_data d;
983         struct file *file;
984         struct dentry *root_dentry;
985         struct fuse_req *init_req;
986         int err;
987         int is_bdev = sb->s_bdev != NULL;
988
989         err = -EINVAL;
990         if (sb->s_flags & MS_MANDLOCK)
991                 goto err;
992
993         sb->s_flags &= ~(MS_NOSEC | MS_I_VERSION);
994
995         if (!parse_fuse_opt(data, &d, is_bdev))
996                 goto err;
997
998         if (is_bdev) {
999 #ifdef CONFIG_BLOCK
1000                 err = -EINVAL;
1001                 if (!sb_set_blocksize(sb, d.blksize))
1002                         goto err;
1003 #endif
1004         } else {
1005                 sb->s_blocksize = PAGE_CACHE_SIZE;
1006                 sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
1007         }
1008         sb->s_magic = FUSE_SUPER_MAGIC;
1009         sb->s_op = &fuse_super_operations;
1010         sb->s_maxbytes = MAX_LFS_FILESIZE;
1011         sb->s_time_gran = 1;
1012         sb->s_export_op = &fuse_export_operations;
1013
1014         file = fget(d.fd);
1015         err = -EINVAL;
1016         if (!file)
1017                 goto err;
1018
1019         if ((file->f_op != &fuse_dev_operations) ||
1020             (file->f_cred->user_ns != &init_user_ns))
1021                 goto err_fput;
1022
1023         fc = kmalloc(sizeof(*fc), GFP_KERNEL);
1024         err = -ENOMEM;
1025         if (!fc)
1026                 goto err_fput;
1027
1028         fuse_conn_init(fc);
1029
1030         fc->dev = sb->s_dev;
1031         fc->sb = sb;
1032         err = fuse_bdi_init(fc, sb);
1033         if (err)
1034                 goto err_put_conn;
1035
1036         sb->s_bdi = &fc->bdi;
1037
1038         /* Handle umasking inside the fuse code */
1039         if (sb->s_flags & MS_POSIXACL)
1040                 fc->dont_mask = 1;
1041         sb->s_flags |= MS_POSIXACL;
1042
1043         fc->release = fuse_free_conn;
1044         fc->flags = d.flags;
1045         fc->user_id = d.user_id;
1046         fc->group_id = d.group_id;
1047         fc->max_read = max_t(unsigned, 4096, d.max_read);
1048
1049         /* Used by get_root_inode() */
1050         sb->s_fs_info = fc;
1051
1052         err = -ENOMEM;
1053         root = fuse_get_root_inode(sb, d.rootmode);
1054         root_dentry = d_make_root(root);
1055         if (!root_dentry)
1056                 goto err_put_conn;
1057         /* only now - we want root dentry with NULL ->d_op */
1058         sb->s_d_op = &fuse_dentry_operations;
1059
1060         init_req = fuse_request_alloc(0);
1061         if (!init_req)
1062                 goto err_put_root;
1063         init_req->background = 1;
1064
1065         if (is_bdev) {
1066                 fc->destroy_req = fuse_request_alloc(0);
1067                 if (!fc->destroy_req)
1068                         goto err_free_init_req;
1069         }
1070
1071         mutex_lock(&fuse_mutex);
1072         err = -EINVAL;
1073         if (file->private_data)
1074                 goto err_unlock;
1075
1076         err = fuse_ctl_add_conn(fc);
1077         if (err)
1078                 goto err_unlock;
1079
1080         list_add_tail(&fc->entry, &fuse_conn_list);
1081         sb->s_root = root_dentry;
1082         fc->connected = 1;
1083         file->private_data = fuse_conn_get(fc);
1084         mutex_unlock(&fuse_mutex);
1085         /*
1086          * atomic_dec_and_test() in fput() provides the necessary
1087          * memory barrier for file->private_data to be visible on all
1088          * CPUs after this
1089          */
1090         fput(file);
1091
1092         fuse_send_init(fc, init_req);
1093
1094         return 0;
1095
1096  err_unlock:
1097         mutex_unlock(&fuse_mutex);
1098  err_free_init_req:
1099         fuse_request_free(init_req);
1100  err_put_root:
1101         dput(root_dentry);
1102  err_put_conn:
1103         fuse_bdi_destroy(fc);
1104         fuse_conn_put(fc);
1105  err_fput:
1106         fput(file);
1107  err:
1108         return err;
1109 }
1110
1111 static struct dentry *fuse_mount(struct file_system_type *fs_type,
1112                        int flags, const char *dev_name,
1113                        void *raw_data)
1114 {
1115         return mount_nodev(fs_type, flags, raw_data, fuse_fill_super);
1116 }
1117
1118 static void fuse_kill_sb_anon(struct super_block *sb)
1119 {
1120         struct fuse_conn *fc = get_fuse_conn_super(sb);
1121
1122         if (fc) {
1123                 down_write(&fc->killsb);
1124                 fc->sb = NULL;
1125                 up_write(&fc->killsb);
1126         }
1127
1128         kill_anon_super(sb);
1129 }
1130
1131 static struct file_system_type fuse_fs_type = {
1132         .owner          = THIS_MODULE,
1133         .name           = "fuse",
1134         .fs_flags       = FS_HAS_SUBTYPE,
1135         .mount          = fuse_mount,
1136         .kill_sb        = fuse_kill_sb_anon,
1137 };
1138 MODULE_ALIAS_FS("fuse");
1139
1140 #ifdef CONFIG_BLOCK
1141 static struct dentry *fuse_mount_blk(struct file_system_type *fs_type,
1142                            int flags, const char *dev_name,
1143                            void *raw_data)
1144 {
1145         return mount_bdev(fs_type, flags, dev_name, raw_data, fuse_fill_super);
1146 }
1147
1148 static void fuse_kill_sb_blk(struct super_block *sb)
1149 {
1150         struct fuse_conn *fc = get_fuse_conn_super(sb);
1151
1152         if (fc) {
1153                 down_write(&fc->killsb);
1154                 fc->sb = NULL;
1155                 up_write(&fc->killsb);
1156         }
1157
1158         kill_block_super(sb);
1159 }
1160
1161 static struct file_system_type fuseblk_fs_type = {
1162         .owner          = THIS_MODULE,
1163         .name           = "fuseblk",
1164         .mount          = fuse_mount_blk,
1165         .kill_sb        = fuse_kill_sb_blk,
1166         .fs_flags       = FS_REQUIRES_DEV | FS_HAS_SUBTYPE,
1167 };
1168 MODULE_ALIAS_FS("fuseblk");
1169
1170 static inline int register_fuseblk(void)
1171 {
1172         return register_filesystem(&fuseblk_fs_type);
1173 }
1174
1175 static inline void unregister_fuseblk(void)
1176 {
1177         unregister_filesystem(&fuseblk_fs_type);
1178 }
1179 #else
1180 static inline int register_fuseblk(void)
1181 {
1182         return 0;
1183 }
1184
1185 static inline void unregister_fuseblk(void)
1186 {
1187 }
1188 #endif
1189
1190 static void fuse_inode_init_once(void *foo)
1191 {
1192         struct inode *inode = foo;
1193
1194         inode_init_once(inode);
1195 }
1196
1197 static int __init fuse_fs_init(void)
1198 {
1199         int err;
1200
1201         fuse_inode_cachep = kmem_cache_create("fuse_inode",
1202                                               sizeof(struct fuse_inode),
1203                                               0, SLAB_HWCACHE_ALIGN,
1204                                               fuse_inode_init_once);
1205         err = -ENOMEM;
1206         if (!fuse_inode_cachep)
1207                 goto out;
1208
1209         err = register_fuseblk();
1210         if (err)
1211                 goto out2;
1212
1213         err = register_filesystem(&fuse_fs_type);
1214         if (err)
1215                 goto out3;
1216
1217         return 0;
1218
1219  out3:
1220         unregister_fuseblk();
1221  out2:
1222         kmem_cache_destroy(fuse_inode_cachep);
1223  out:
1224         return err;
1225 }
1226
1227 static void fuse_fs_cleanup(void)
1228 {
1229         unregister_filesystem(&fuse_fs_type);
1230         unregister_fuseblk();
1231
1232         /*
1233          * Make sure all delayed rcu free inodes are flushed before we
1234          * destroy cache.
1235          */
1236         rcu_barrier();
1237         kmem_cache_destroy(fuse_inode_cachep);
1238 }
1239
1240 static struct kobject *fuse_kobj;
1241
1242 static int fuse_sysfs_init(void)
1243 {
1244         int err;
1245
1246         fuse_kobj = kobject_create_and_add("fuse", fs_kobj);
1247         if (!fuse_kobj) {
1248                 err = -ENOMEM;
1249                 goto out_err;
1250         }
1251
1252         err = sysfs_create_mount_point(fuse_kobj, "connections");
1253         if (err)
1254                 goto out_fuse_unregister;
1255
1256         return 0;
1257
1258  out_fuse_unregister:
1259         kobject_put(fuse_kobj);
1260  out_err:
1261         return err;
1262 }
1263
1264 static void fuse_sysfs_cleanup(void)
1265 {
1266         sysfs_remove_mount_point(fuse_kobj, "connections");
1267         kobject_put(fuse_kobj);
1268 }
1269
1270 static int __init fuse_init(void)
1271 {
1272         int res;
1273
1274         printk(KERN_INFO "fuse init (API version %i.%i)\n",
1275                FUSE_KERNEL_VERSION, FUSE_KERNEL_MINOR_VERSION);
1276
1277         INIT_LIST_HEAD(&fuse_conn_list);
1278         res = fuse_fs_init();
1279         if (res)
1280                 goto err;
1281
1282         res = fuse_dev_init();
1283         if (res)
1284                 goto err_fs_cleanup;
1285
1286         res = fuse_sysfs_init();
1287         if (res)
1288                 goto err_dev_cleanup;
1289
1290         res = fuse_ctl_init();
1291         if (res)
1292                 goto err_sysfs_cleanup;
1293
1294         sanitize_global_limit(&max_user_bgreq);
1295         sanitize_global_limit(&max_user_congthresh);
1296
1297         return 0;
1298
1299  err_sysfs_cleanup:
1300         fuse_sysfs_cleanup();
1301  err_dev_cleanup:
1302         fuse_dev_cleanup();
1303  err_fs_cleanup:
1304         fuse_fs_cleanup();
1305  err:
1306         return res;
1307 }
1308
1309 static void __exit fuse_exit(void)
1310 {
1311         printk(KERN_DEBUG "fuse exit\n");
1312
1313         fuse_ctl_cleanup();
1314         fuse_sysfs_cleanup();
1315         fuse_fs_cleanup();
1316         fuse_dev_cleanup();
1317 }
1318
1319 module_init(fuse_init);
1320 module_exit(fuse_exit);