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fuse: limit user-specified values of max background requests
[deliverable/linux.git] / 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 static 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 static 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 unsigned user_id;
64 unsigned 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 static struct inode *fuse_alloc_inode(struct super_block *sb)
75 {
76 struct inode *inode;
77 struct fuse_inode *fi;
78
79 inode = kmem_cache_alloc(fuse_inode_cachep, GFP_KERNEL);
80 if (!inode)
81 return NULL;
82
83 fi = get_fuse_inode(inode);
84 fi->i_time = 0;
85 fi->nodeid = 0;
86 fi->nlookup = 0;
87 fi->attr_version = 0;
88 fi->writectr = 0;
89 INIT_LIST_HEAD(&fi->write_files);
90 INIT_LIST_HEAD(&fi->queued_writes);
91 INIT_LIST_HEAD(&fi->writepages);
92 init_waitqueue_head(&fi->page_waitq);
93 fi->forget_req = fuse_request_alloc();
94 if (!fi->forget_req) {
95 kmem_cache_free(fuse_inode_cachep, inode);
96 return NULL;
97 }
98
99 return inode;
100 }
101
102 static void fuse_destroy_inode(struct inode *inode)
103 {
104 struct fuse_inode *fi = get_fuse_inode(inode);
105 BUG_ON(!list_empty(&fi->write_files));
106 BUG_ON(!list_empty(&fi->queued_writes));
107 if (fi->forget_req)
108 fuse_request_free(fi->forget_req);
109 kmem_cache_free(fuse_inode_cachep, inode);
110 }
111
112 void fuse_send_forget(struct fuse_conn *fc, struct fuse_req *req,
113 u64 nodeid, u64 nlookup)
114 {
115 struct fuse_forget_in *inarg = &req->misc.forget_in;
116 inarg->nlookup = nlookup;
117 req->in.h.opcode = FUSE_FORGET;
118 req->in.h.nodeid = nodeid;
119 req->in.numargs = 1;
120 req->in.args[0].size = sizeof(struct fuse_forget_in);
121 req->in.args[0].value = inarg;
122 fuse_request_send_noreply(fc, req);
123 }
124
125 static void fuse_clear_inode(struct inode *inode)
126 {
127 if (inode->i_sb->s_flags & MS_ACTIVE) {
128 struct fuse_conn *fc = get_fuse_conn(inode);
129 struct fuse_inode *fi = get_fuse_inode(inode);
130 fuse_send_forget(fc, fi->forget_req, fi->nodeid, fi->nlookup);
131 fi->forget_req = NULL;
132 }
133 }
134
135 static int fuse_remount_fs(struct super_block *sb, int *flags, char *data)
136 {
137 if (*flags & MS_MANDLOCK)
138 return -EINVAL;
139
140 return 0;
141 }
142
143 void fuse_truncate(struct address_space *mapping, loff_t offset)
144 {
145 /* See vmtruncate() */
146 unmap_mapping_range(mapping, offset + PAGE_SIZE - 1, 0, 1);
147 truncate_inode_pages(mapping, offset);
148 unmap_mapping_range(mapping, offset + PAGE_SIZE - 1, 0, 1);
149 }
150
151 void fuse_change_attributes_common(struct inode *inode, struct fuse_attr *attr,
152 u64 attr_valid)
153 {
154 struct fuse_conn *fc = get_fuse_conn(inode);
155 struct fuse_inode *fi = get_fuse_inode(inode);
156
157 fi->attr_version = ++fc->attr_version;
158 fi->i_time = attr_valid;
159
160 inode->i_ino = attr->ino;
161 inode->i_mode = (inode->i_mode & S_IFMT) | (attr->mode & 07777);
162 inode->i_nlink = attr->nlink;
163 inode->i_uid = attr->uid;
164 inode->i_gid = attr->gid;
165 inode->i_blocks = attr->blocks;
166 inode->i_atime.tv_sec = attr->atime;
167 inode->i_atime.tv_nsec = attr->atimensec;
168 inode->i_mtime.tv_sec = attr->mtime;
169 inode->i_mtime.tv_nsec = attr->mtimensec;
170 inode->i_ctime.tv_sec = attr->ctime;
171 inode->i_ctime.tv_nsec = attr->ctimensec;
172
173 if (attr->blksize != 0)
174 inode->i_blkbits = ilog2(attr->blksize);
175 else
176 inode->i_blkbits = inode->i_sb->s_blocksize_bits;
177
178 /*
179 * Don't set the sticky bit in i_mode, unless we want the VFS
180 * to check permissions. This prevents failures due to the
181 * check in may_delete().
182 */
183 fi->orig_i_mode = inode->i_mode;
184 if (!(fc->flags & FUSE_DEFAULT_PERMISSIONS))
185 inode->i_mode &= ~S_ISVTX;
186 }
187
188 void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr,
189 u64 attr_valid, u64 attr_version)
190 {
191 struct fuse_conn *fc = get_fuse_conn(inode);
192 struct fuse_inode *fi = get_fuse_inode(inode);
193 loff_t oldsize;
194
195 spin_lock(&fc->lock);
196 if (attr_version != 0 && fi->attr_version > attr_version) {
197 spin_unlock(&fc->lock);
198 return;
199 }
200
201 fuse_change_attributes_common(inode, attr, attr_valid);
202
203 oldsize = inode->i_size;
204 i_size_write(inode, attr->size);
205 spin_unlock(&fc->lock);
206
207 if (S_ISREG(inode->i_mode) && oldsize != attr->size) {
208 if (attr->size < oldsize)
209 fuse_truncate(inode->i_mapping, attr->size);
210 invalidate_inode_pages2(inode->i_mapping);
211 }
212 }
213
214 static void fuse_init_inode(struct inode *inode, struct fuse_attr *attr)
215 {
216 inode->i_mode = attr->mode & S_IFMT;
217 inode->i_size = attr->size;
218 if (S_ISREG(inode->i_mode)) {
219 fuse_init_common(inode);
220 fuse_init_file_inode(inode);
221 } else if (S_ISDIR(inode->i_mode))
222 fuse_init_dir(inode);
223 else if (S_ISLNK(inode->i_mode))
224 fuse_init_symlink(inode);
225 else if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode) ||
226 S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode)) {
227 fuse_init_common(inode);
228 init_special_inode(inode, inode->i_mode,
229 new_decode_dev(attr->rdev));
230 } else
231 BUG();
232 }
233
234 int fuse_inode_eq(struct inode *inode, void *_nodeidp)
235 {
236 u64 nodeid = *(u64 *) _nodeidp;
237 if (get_node_id(inode) == nodeid)
238 return 1;
239 else
240 return 0;
241 }
242
243 static int fuse_inode_set(struct inode *inode, void *_nodeidp)
244 {
245 u64 nodeid = *(u64 *) _nodeidp;
246 get_fuse_inode(inode)->nodeid = nodeid;
247 return 0;
248 }
249
250 struct inode *fuse_iget(struct super_block *sb, u64 nodeid,
251 int generation, struct fuse_attr *attr,
252 u64 attr_valid, u64 attr_version)
253 {
254 struct inode *inode;
255 struct fuse_inode *fi;
256 struct fuse_conn *fc = get_fuse_conn_super(sb);
257
258 retry:
259 inode = iget5_locked(sb, nodeid, fuse_inode_eq, fuse_inode_set, &nodeid);
260 if (!inode)
261 return NULL;
262
263 if ((inode->i_state & I_NEW)) {
264 inode->i_flags |= S_NOATIME|S_NOCMTIME;
265 inode->i_generation = generation;
266 inode->i_data.backing_dev_info = &fc->bdi;
267 fuse_init_inode(inode, attr);
268 unlock_new_inode(inode);
269 } else if ((inode->i_mode ^ attr->mode) & S_IFMT) {
270 /* Inode has changed type, any I/O on the old should fail */
271 make_bad_inode(inode);
272 iput(inode);
273 goto retry;
274 }
275
276 fi = get_fuse_inode(inode);
277 spin_lock(&fc->lock);
278 fi->nlookup++;
279 spin_unlock(&fc->lock);
280 fuse_change_attributes(inode, attr, attr_valid, attr_version);
281
282 return inode;
283 }
284
285 int fuse_reverse_inval_inode(struct super_block *sb, u64 nodeid,
286 loff_t offset, loff_t len)
287 {
288 struct inode *inode;
289 pgoff_t pg_start;
290 pgoff_t pg_end;
291
292 inode = ilookup5(sb, nodeid, fuse_inode_eq, &nodeid);
293 if (!inode)
294 return -ENOENT;
295
296 fuse_invalidate_attr(inode);
297 if (offset >= 0) {
298 pg_start = offset >> PAGE_CACHE_SHIFT;
299 if (len <= 0)
300 pg_end = -1;
301 else
302 pg_end = (offset + len - 1) >> PAGE_CACHE_SHIFT;
303 invalidate_inode_pages2_range(inode->i_mapping,
304 pg_start, pg_end);
305 }
306 iput(inode);
307 return 0;
308 }
309
310 static void fuse_umount_begin(struct super_block *sb)
311 {
312 fuse_abort_conn(get_fuse_conn_super(sb));
313 }
314
315 static void fuse_send_destroy(struct fuse_conn *fc)
316 {
317 struct fuse_req *req = fc->destroy_req;
318 if (req && fc->conn_init) {
319 fc->destroy_req = NULL;
320 req->in.h.opcode = FUSE_DESTROY;
321 req->force = 1;
322 fuse_request_send(fc, req);
323 fuse_put_request(fc, req);
324 }
325 }
326
327 static void fuse_bdi_destroy(struct fuse_conn *fc)
328 {
329 if (fc->bdi_initialized)
330 bdi_destroy(&fc->bdi);
331 }
332
333 void fuse_conn_kill(struct fuse_conn *fc)
334 {
335 spin_lock(&fc->lock);
336 fc->connected = 0;
337 fc->blocked = 0;
338 spin_unlock(&fc->lock);
339 /* Flush all readers on this fs */
340 kill_fasync(&fc->fasync, SIGIO, POLL_IN);
341 wake_up_all(&fc->waitq);
342 wake_up_all(&fc->blocked_waitq);
343 wake_up_all(&fc->reserved_req_waitq);
344 mutex_lock(&fuse_mutex);
345 list_del(&fc->entry);
346 fuse_ctl_remove_conn(fc);
347 mutex_unlock(&fuse_mutex);
348 fuse_bdi_destroy(fc);
349 }
350 EXPORT_SYMBOL_GPL(fuse_conn_kill);
351
352 static void fuse_put_super(struct super_block *sb)
353 {
354 struct fuse_conn *fc = get_fuse_conn_super(sb);
355
356 fuse_send_destroy(fc);
357 fuse_conn_kill(fc);
358 fuse_conn_put(fc);
359 }
360
361 static void convert_fuse_statfs(struct kstatfs *stbuf, struct fuse_kstatfs *attr)
362 {
363 stbuf->f_type = FUSE_SUPER_MAGIC;
364 stbuf->f_bsize = attr->bsize;
365 stbuf->f_frsize = attr->frsize;
366 stbuf->f_blocks = attr->blocks;
367 stbuf->f_bfree = attr->bfree;
368 stbuf->f_bavail = attr->bavail;
369 stbuf->f_files = attr->files;
370 stbuf->f_ffree = attr->ffree;
371 stbuf->f_namelen = attr->namelen;
372 /* fsid is left zero */
373 }
374
375 static int fuse_statfs(struct dentry *dentry, struct kstatfs *buf)
376 {
377 struct super_block *sb = dentry->d_sb;
378 struct fuse_conn *fc = get_fuse_conn_super(sb);
379 struct fuse_req *req;
380 struct fuse_statfs_out outarg;
381 int err;
382
383 if (!fuse_allow_task(fc, current)) {
384 buf->f_type = FUSE_SUPER_MAGIC;
385 return 0;
386 }
387
388 req = fuse_get_req(fc);
389 if (IS_ERR(req))
390 return PTR_ERR(req);
391
392 memset(&outarg, 0, sizeof(outarg));
393 req->in.numargs = 0;
394 req->in.h.opcode = FUSE_STATFS;
395 req->in.h.nodeid = get_node_id(dentry->d_inode);
396 req->out.numargs = 1;
397 req->out.args[0].size =
398 fc->minor < 4 ? FUSE_COMPAT_STATFS_SIZE : sizeof(outarg);
399 req->out.args[0].value = &outarg;
400 fuse_request_send(fc, req);
401 err = req->out.h.error;
402 if (!err)
403 convert_fuse_statfs(buf, &outarg.st);
404 fuse_put_request(fc, req);
405 return err;
406 }
407
408 enum {
409 OPT_FD,
410 OPT_ROOTMODE,
411 OPT_USER_ID,
412 OPT_GROUP_ID,
413 OPT_DEFAULT_PERMISSIONS,
414 OPT_ALLOW_OTHER,
415 OPT_MAX_READ,
416 OPT_BLKSIZE,
417 OPT_ERR
418 };
419
420 static const match_table_t tokens = {
421 {OPT_FD, "fd=%u"},
422 {OPT_ROOTMODE, "rootmode=%o"},
423 {OPT_USER_ID, "user_id=%u"},
424 {OPT_GROUP_ID, "group_id=%u"},
425 {OPT_DEFAULT_PERMISSIONS, "default_permissions"},
426 {OPT_ALLOW_OTHER, "allow_other"},
427 {OPT_MAX_READ, "max_read=%u"},
428 {OPT_BLKSIZE, "blksize=%u"},
429 {OPT_ERR, NULL}
430 };
431
432 static int parse_fuse_opt(char *opt, struct fuse_mount_data *d, int is_bdev)
433 {
434 char *p;
435 memset(d, 0, sizeof(struct fuse_mount_data));
436 d->max_read = ~0;
437 d->blksize = FUSE_DEFAULT_BLKSIZE;
438
439 while ((p = strsep(&opt, ",")) != NULL) {
440 int token;
441 int value;
442 substring_t args[MAX_OPT_ARGS];
443 if (!*p)
444 continue;
445
446 token = match_token(p, tokens, args);
447 switch (token) {
448 case OPT_FD:
449 if (match_int(&args[0], &value))
450 return 0;
451 d->fd = value;
452 d->fd_present = 1;
453 break;
454
455 case OPT_ROOTMODE:
456 if (match_octal(&args[0], &value))
457 return 0;
458 if (!fuse_valid_type(value))
459 return 0;
460 d->rootmode = value;
461 d->rootmode_present = 1;
462 break;
463
464 case OPT_USER_ID:
465 if (match_int(&args[0], &value))
466 return 0;
467 d->user_id = value;
468 d->user_id_present = 1;
469 break;
470
471 case OPT_GROUP_ID:
472 if (match_int(&args[0], &value))
473 return 0;
474 d->group_id = value;
475 d->group_id_present = 1;
476 break;
477
478 case OPT_DEFAULT_PERMISSIONS:
479 d->flags |= FUSE_DEFAULT_PERMISSIONS;
480 break;
481
482 case OPT_ALLOW_OTHER:
483 d->flags |= FUSE_ALLOW_OTHER;
484 break;
485
486 case OPT_MAX_READ:
487 if (match_int(&args[0], &value))
488 return 0;
489 d->max_read = value;
490 break;
491
492 case OPT_BLKSIZE:
493 if (!is_bdev || match_int(&args[0], &value))
494 return 0;
495 d->blksize = value;
496 break;
497
498 default:
499 return 0;
500 }
501 }
502
503 if (!d->fd_present || !d->rootmode_present ||
504 !d->user_id_present || !d->group_id_present)
505 return 0;
506
507 return 1;
508 }
509
510 static int fuse_show_options(struct seq_file *m, struct vfsmount *mnt)
511 {
512 struct fuse_conn *fc = get_fuse_conn_super(mnt->mnt_sb);
513
514 seq_printf(m, ",user_id=%u", fc->user_id);
515 seq_printf(m, ",group_id=%u", fc->group_id);
516 if (fc->flags & FUSE_DEFAULT_PERMISSIONS)
517 seq_puts(m, ",default_permissions");
518 if (fc->flags & FUSE_ALLOW_OTHER)
519 seq_puts(m, ",allow_other");
520 if (fc->max_read != ~0)
521 seq_printf(m, ",max_read=%u", fc->max_read);
522 if (mnt->mnt_sb->s_bdev &&
523 mnt->mnt_sb->s_blocksize != FUSE_DEFAULT_BLKSIZE)
524 seq_printf(m, ",blksize=%lu", mnt->mnt_sb->s_blocksize);
525 return 0;
526 }
527
528 void fuse_conn_init(struct fuse_conn *fc)
529 {
530 memset(fc, 0, sizeof(*fc));
531 spin_lock_init(&fc->lock);
532 mutex_init(&fc->inst_mutex);
533 init_rwsem(&fc->killsb);
534 atomic_set(&fc->count, 1);
535 init_waitqueue_head(&fc->waitq);
536 init_waitqueue_head(&fc->blocked_waitq);
537 init_waitqueue_head(&fc->reserved_req_waitq);
538 INIT_LIST_HEAD(&fc->pending);
539 INIT_LIST_HEAD(&fc->processing);
540 INIT_LIST_HEAD(&fc->io);
541 INIT_LIST_HEAD(&fc->interrupts);
542 INIT_LIST_HEAD(&fc->bg_queue);
543 INIT_LIST_HEAD(&fc->entry);
544 atomic_set(&fc->num_waiting, 0);
545 fc->max_background = FUSE_DEFAULT_MAX_BACKGROUND;
546 fc->congestion_threshold = FUSE_DEFAULT_CONGESTION_THRESHOLD;
547 fc->khctr = 0;
548 fc->polled_files = RB_ROOT;
549 fc->reqctr = 0;
550 fc->blocked = 1;
551 fc->attr_version = 1;
552 get_random_bytes(&fc->scramble_key, sizeof(fc->scramble_key));
553 }
554 EXPORT_SYMBOL_GPL(fuse_conn_init);
555
556 void fuse_conn_put(struct fuse_conn *fc)
557 {
558 if (atomic_dec_and_test(&fc->count)) {
559 if (fc->destroy_req)
560 fuse_request_free(fc->destroy_req);
561 mutex_destroy(&fc->inst_mutex);
562 fc->release(fc);
563 }
564 }
565 EXPORT_SYMBOL_GPL(fuse_conn_put);
566
567 struct fuse_conn *fuse_conn_get(struct fuse_conn *fc)
568 {
569 atomic_inc(&fc->count);
570 return fc;
571 }
572 EXPORT_SYMBOL_GPL(fuse_conn_get);
573
574 static struct inode *fuse_get_root_inode(struct super_block *sb, unsigned mode)
575 {
576 struct fuse_attr attr;
577 memset(&attr, 0, sizeof(attr));
578
579 attr.mode = mode;
580 attr.ino = FUSE_ROOT_ID;
581 attr.nlink = 1;
582 return fuse_iget(sb, 1, 0, &attr, 0, 0);
583 }
584
585 struct fuse_inode_handle {
586 u64 nodeid;
587 u32 generation;
588 };
589
590 static struct dentry *fuse_get_dentry(struct super_block *sb,
591 struct fuse_inode_handle *handle)
592 {
593 struct fuse_conn *fc = get_fuse_conn_super(sb);
594 struct inode *inode;
595 struct dentry *entry;
596 int err = -ESTALE;
597
598 if (handle->nodeid == 0)
599 goto out_err;
600
601 inode = ilookup5(sb, handle->nodeid, fuse_inode_eq, &handle->nodeid);
602 if (!inode) {
603 struct fuse_entry_out outarg;
604 struct qstr name;
605
606 if (!fc->export_support)
607 goto out_err;
608
609 name.len = 1;
610 name.name = ".";
611 err = fuse_lookup_name(sb, handle->nodeid, &name, &outarg,
612 &inode);
613 if (err && err != -ENOENT)
614 goto out_err;
615 if (err || !inode) {
616 err = -ESTALE;
617 goto out_err;
618 }
619 err = -EIO;
620 if (get_node_id(inode) != handle->nodeid)
621 goto out_iput;
622 }
623 err = -ESTALE;
624 if (inode->i_generation != handle->generation)
625 goto out_iput;
626
627 entry = d_obtain_alias(inode);
628 if (!IS_ERR(entry) && get_node_id(inode) != FUSE_ROOT_ID) {
629 entry->d_op = &fuse_dentry_operations;
630 fuse_invalidate_entry_cache(entry);
631 }
632
633 return entry;
634
635 out_iput:
636 iput(inode);
637 out_err:
638 return ERR_PTR(err);
639 }
640
641 static int fuse_encode_fh(struct dentry *dentry, u32 *fh, int *max_len,
642 int connectable)
643 {
644 struct inode *inode = dentry->d_inode;
645 bool encode_parent = connectable && !S_ISDIR(inode->i_mode);
646 int len = encode_parent ? 6 : 3;
647 u64 nodeid;
648 u32 generation;
649
650 if (*max_len < len)
651 return 255;
652
653 nodeid = get_fuse_inode(inode)->nodeid;
654 generation = inode->i_generation;
655
656 fh[0] = (u32)(nodeid >> 32);
657 fh[1] = (u32)(nodeid & 0xffffffff);
658 fh[2] = generation;
659
660 if (encode_parent) {
661 struct inode *parent;
662
663 spin_lock(&dentry->d_lock);
664 parent = dentry->d_parent->d_inode;
665 nodeid = get_fuse_inode(parent)->nodeid;
666 generation = parent->i_generation;
667 spin_unlock(&dentry->d_lock);
668
669 fh[3] = (u32)(nodeid >> 32);
670 fh[4] = (u32)(nodeid & 0xffffffff);
671 fh[5] = generation;
672 }
673
674 *max_len = len;
675 return encode_parent ? 0x82 : 0x81;
676 }
677
678 static struct dentry *fuse_fh_to_dentry(struct super_block *sb,
679 struct fid *fid, int fh_len, int fh_type)
680 {
681 struct fuse_inode_handle handle;
682
683 if ((fh_type != 0x81 && fh_type != 0x82) || fh_len < 3)
684 return NULL;
685
686 handle.nodeid = (u64) fid->raw[0] << 32;
687 handle.nodeid |= (u64) fid->raw[1];
688 handle.generation = fid->raw[2];
689 return fuse_get_dentry(sb, &handle);
690 }
691
692 static struct dentry *fuse_fh_to_parent(struct super_block *sb,
693 struct fid *fid, int fh_len, int fh_type)
694 {
695 struct fuse_inode_handle parent;
696
697 if (fh_type != 0x82 || fh_len < 6)
698 return NULL;
699
700 parent.nodeid = (u64) fid->raw[3] << 32;
701 parent.nodeid |= (u64) fid->raw[4];
702 parent.generation = fid->raw[5];
703 return fuse_get_dentry(sb, &parent);
704 }
705
706 static struct dentry *fuse_get_parent(struct dentry *child)
707 {
708 struct inode *child_inode = child->d_inode;
709 struct fuse_conn *fc = get_fuse_conn(child_inode);
710 struct inode *inode;
711 struct dentry *parent;
712 struct fuse_entry_out outarg;
713 struct qstr name;
714 int err;
715
716 if (!fc->export_support)
717 return ERR_PTR(-ESTALE);
718
719 name.len = 2;
720 name.name = "..";
721 err = fuse_lookup_name(child_inode->i_sb, get_node_id(child_inode),
722 &name, &outarg, &inode);
723 if (err) {
724 if (err == -ENOENT)
725 return ERR_PTR(-ESTALE);
726 return ERR_PTR(err);
727 }
728
729 parent = d_obtain_alias(inode);
730 if (!IS_ERR(parent) && get_node_id(inode) != FUSE_ROOT_ID) {
731 parent->d_op = &fuse_dentry_operations;
732 fuse_invalidate_entry_cache(parent);
733 }
734
735 return parent;
736 }
737
738 static const struct export_operations fuse_export_operations = {
739 .fh_to_dentry = fuse_fh_to_dentry,
740 .fh_to_parent = fuse_fh_to_parent,
741 .encode_fh = fuse_encode_fh,
742 .get_parent = fuse_get_parent,
743 };
744
745 static const struct super_operations fuse_super_operations = {
746 .alloc_inode = fuse_alloc_inode,
747 .destroy_inode = fuse_destroy_inode,
748 .clear_inode = fuse_clear_inode,
749 .drop_inode = generic_delete_inode,
750 .remount_fs = fuse_remount_fs,
751 .put_super = fuse_put_super,
752 .umount_begin = fuse_umount_begin,
753 .statfs = fuse_statfs,
754 .show_options = fuse_show_options,
755 };
756
757 static void sanitize_global_limit(unsigned *limit)
758 {
759 if (*limit == 0)
760 *limit = ((num_physpages << PAGE_SHIFT) >> 13) /
761 sizeof(struct fuse_req);
762
763 if (*limit >= 1 << 16)
764 *limit = (1 << 16) - 1;
765 }
766
767 static int set_global_limit(const char *val, struct kernel_param *kp)
768 {
769 int rv;
770
771 rv = param_set_uint(val, kp);
772 if (rv)
773 return rv;
774
775 sanitize_global_limit((unsigned *)kp->arg);
776
777 return 0;
778 }
779
780 static void process_init_limits(struct fuse_conn *fc, struct fuse_init_out *arg)
781 {
782 int cap_sys_admin = capable(CAP_SYS_ADMIN);
783
784 if (arg->minor < 13)
785 return;
786
787 sanitize_global_limit(&max_user_bgreq);
788 sanitize_global_limit(&max_user_congthresh);
789
790 if (arg->max_background) {
791 fc->max_background = arg->max_background;
792
793 if (!cap_sys_admin && fc->max_background > max_user_bgreq)
794 fc->max_background = max_user_bgreq;
795 }
796 if (arg->congestion_threshold) {
797 fc->congestion_threshold = arg->congestion_threshold;
798
799 if (!cap_sys_admin &&
800 fc->congestion_threshold > max_user_congthresh)
801 fc->congestion_threshold = max_user_congthresh;
802 }
803 }
804
805 static void process_init_reply(struct fuse_conn *fc, struct fuse_req *req)
806 {
807 struct fuse_init_out *arg = &req->misc.init_out;
808
809 if (req->out.h.error || arg->major != FUSE_KERNEL_VERSION)
810 fc->conn_error = 1;
811 else {
812 unsigned long ra_pages;
813
814 process_init_limits(fc, arg);
815
816 if (arg->minor >= 6) {
817 ra_pages = arg->max_readahead / PAGE_CACHE_SIZE;
818 if (arg->flags & FUSE_ASYNC_READ)
819 fc->async_read = 1;
820 if (!(arg->flags & FUSE_POSIX_LOCKS))
821 fc->no_lock = 1;
822 if (arg->flags & FUSE_ATOMIC_O_TRUNC)
823 fc->atomic_o_trunc = 1;
824 if (arg->minor >= 9) {
825 /* LOOKUP has dependency on proto version */
826 if (arg->flags & FUSE_EXPORT_SUPPORT)
827 fc->export_support = 1;
828 }
829 if (arg->flags & FUSE_BIG_WRITES)
830 fc->big_writes = 1;
831 if (arg->flags & FUSE_DONT_MASK)
832 fc->dont_mask = 1;
833 } else {
834 ra_pages = fc->max_read / PAGE_CACHE_SIZE;
835 fc->no_lock = 1;
836 }
837
838 fc->bdi.ra_pages = min(fc->bdi.ra_pages, ra_pages);
839 fc->minor = arg->minor;
840 fc->max_write = arg->minor < 5 ? 4096 : arg->max_write;
841 fc->max_write = max_t(unsigned, 4096, fc->max_write);
842 fc->conn_init = 1;
843 }
844 fc->blocked = 0;
845 wake_up_all(&fc->blocked_waitq);
846 }
847
848 static void fuse_send_init(struct fuse_conn *fc, struct fuse_req *req)
849 {
850 struct fuse_init_in *arg = &req->misc.init_in;
851
852 arg->major = FUSE_KERNEL_VERSION;
853 arg->minor = FUSE_KERNEL_MINOR_VERSION;
854 arg->max_readahead = fc->bdi.ra_pages * PAGE_CACHE_SIZE;
855 arg->flags |= FUSE_ASYNC_READ | FUSE_POSIX_LOCKS | FUSE_ATOMIC_O_TRUNC |
856 FUSE_EXPORT_SUPPORT | FUSE_BIG_WRITES | FUSE_DONT_MASK;
857 req->in.h.opcode = FUSE_INIT;
858 req->in.numargs = 1;
859 req->in.args[0].size = sizeof(*arg);
860 req->in.args[0].value = arg;
861 req->out.numargs = 1;
862 /* Variable length arguement used for backward compatibility
863 with interface version < 7.5. Rest of init_out is zeroed
864 by do_get_request(), so a short reply is not a problem */
865 req->out.argvar = 1;
866 req->out.args[0].size = sizeof(struct fuse_init_out);
867 req->out.args[0].value = &req->misc.init_out;
868 req->end = process_init_reply;
869 fuse_request_send_background(fc, req);
870 }
871
872 static void fuse_free_conn(struct fuse_conn *fc)
873 {
874 kfree(fc);
875 }
876
877 static int fuse_bdi_init(struct fuse_conn *fc, struct super_block *sb)
878 {
879 int err;
880
881 fc->bdi.ra_pages = (VM_MAX_READAHEAD * 1024) / PAGE_CACHE_SIZE;
882 fc->bdi.unplug_io_fn = default_unplug_io_fn;
883 /* fuse does it's own writeback accounting */
884 fc->bdi.capabilities = BDI_CAP_NO_ACCT_WB;
885
886 err = bdi_init(&fc->bdi);
887 if (err)
888 return err;
889
890 fc->bdi_initialized = 1;
891
892 if (sb->s_bdev) {
893 err = bdi_register(&fc->bdi, NULL, "%u:%u-fuseblk",
894 MAJOR(fc->dev), MINOR(fc->dev));
895 } else {
896 err = bdi_register_dev(&fc->bdi, fc->dev);
897 }
898
899 if (err)
900 return err;
901
902 /*
903 * For a single fuse filesystem use max 1% of dirty +
904 * writeback threshold.
905 *
906 * This gives about 1M of write buffer for memory maps on a
907 * machine with 1G and 10% dirty_ratio, which should be more
908 * than enough.
909 *
910 * Privileged users can raise it by writing to
911 *
912 * /sys/class/bdi/<bdi>/max_ratio
913 */
914 bdi_set_max_ratio(&fc->bdi, 1);
915
916 return 0;
917 }
918
919 static int fuse_fill_super(struct super_block *sb, void *data, int silent)
920 {
921 struct fuse_conn *fc;
922 struct inode *root;
923 struct fuse_mount_data d;
924 struct file *file;
925 struct dentry *root_dentry;
926 struct fuse_req *init_req;
927 int err;
928 int is_bdev = sb->s_bdev != NULL;
929
930 err = -EINVAL;
931 if (sb->s_flags & MS_MANDLOCK)
932 goto err;
933
934 if (!parse_fuse_opt((char *) data, &d, is_bdev))
935 goto err;
936
937 if (is_bdev) {
938 #ifdef CONFIG_BLOCK
939 err = -EINVAL;
940 if (!sb_set_blocksize(sb, d.blksize))
941 goto err;
942 #endif
943 } else {
944 sb->s_blocksize = PAGE_CACHE_SIZE;
945 sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
946 }
947 sb->s_magic = FUSE_SUPER_MAGIC;
948 sb->s_op = &fuse_super_operations;
949 sb->s_maxbytes = MAX_LFS_FILESIZE;
950 sb->s_export_op = &fuse_export_operations;
951
952 file = fget(d.fd);
953 err = -EINVAL;
954 if (!file)
955 goto err;
956
957 if (file->f_op != &fuse_dev_operations)
958 goto err_fput;
959
960 fc = kmalloc(sizeof(*fc), GFP_KERNEL);
961 err = -ENOMEM;
962 if (!fc)
963 goto err_fput;
964
965 fuse_conn_init(fc);
966
967 fc->dev = sb->s_dev;
968 fc->sb = sb;
969 err = fuse_bdi_init(fc, sb);
970 if (err)
971 goto err_put_conn;
972
973 /* Handle umasking inside the fuse code */
974 if (sb->s_flags & MS_POSIXACL)
975 fc->dont_mask = 1;
976 sb->s_flags |= MS_POSIXACL;
977
978 fc->release = fuse_free_conn;
979 fc->flags = d.flags;
980 fc->user_id = d.user_id;
981 fc->group_id = d.group_id;
982 fc->max_read = max_t(unsigned, 4096, d.max_read);
983
984 /* Used by get_root_inode() */
985 sb->s_fs_info = fc;
986
987 err = -ENOMEM;
988 root = fuse_get_root_inode(sb, d.rootmode);
989 if (!root)
990 goto err_put_conn;
991
992 root_dentry = d_alloc_root(root);
993 if (!root_dentry) {
994 iput(root);
995 goto err_put_conn;
996 }
997
998 init_req = fuse_request_alloc();
999 if (!init_req)
1000 goto err_put_root;
1001
1002 if (is_bdev) {
1003 fc->destroy_req = fuse_request_alloc();
1004 if (!fc->destroy_req)
1005 goto err_free_init_req;
1006 }
1007
1008 mutex_lock(&fuse_mutex);
1009 err = -EINVAL;
1010 if (file->private_data)
1011 goto err_unlock;
1012
1013 err = fuse_ctl_add_conn(fc);
1014 if (err)
1015 goto err_unlock;
1016
1017 list_add_tail(&fc->entry, &fuse_conn_list);
1018 sb->s_root = root_dentry;
1019 fc->connected = 1;
1020 file->private_data = fuse_conn_get(fc);
1021 mutex_unlock(&fuse_mutex);
1022 /*
1023 * atomic_dec_and_test() in fput() provides the necessary
1024 * memory barrier for file->private_data to be visible on all
1025 * CPUs after this
1026 */
1027 fput(file);
1028
1029 fuse_send_init(fc, init_req);
1030
1031 return 0;
1032
1033 err_unlock:
1034 mutex_unlock(&fuse_mutex);
1035 err_free_init_req:
1036 fuse_request_free(init_req);
1037 err_put_root:
1038 dput(root_dentry);
1039 err_put_conn:
1040 fuse_bdi_destroy(fc);
1041 fuse_conn_put(fc);
1042 err_fput:
1043 fput(file);
1044 err:
1045 return err;
1046 }
1047
1048 static int fuse_get_sb(struct file_system_type *fs_type,
1049 int flags, const char *dev_name,
1050 void *raw_data, struct vfsmount *mnt)
1051 {
1052 return get_sb_nodev(fs_type, flags, raw_data, fuse_fill_super, mnt);
1053 }
1054
1055 static void fuse_kill_sb_anon(struct super_block *sb)
1056 {
1057 struct fuse_conn *fc = get_fuse_conn_super(sb);
1058
1059 if (fc) {
1060 down_write(&fc->killsb);
1061 fc->sb = NULL;
1062 up_write(&fc->killsb);
1063 }
1064
1065 kill_anon_super(sb);
1066 }
1067
1068 static struct file_system_type fuse_fs_type = {
1069 .owner = THIS_MODULE,
1070 .name = "fuse",
1071 .fs_flags = FS_HAS_SUBTYPE,
1072 .get_sb = fuse_get_sb,
1073 .kill_sb = fuse_kill_sb_anon,
1074 };
1075
1076 #ifdef CONFIG_BLOCK
1077 static int fuse_get_sb_blk(struct file_system_type *fs_type,
1078 int flags, const char *dev_name,
1079 void *raw_data, struct vfsmount *mnt)
1080 {
1081 return get_sb_bdev(fs_type, flags, dev_name, raw_data, fuse_fill_super,
1082 mnt);
1083 }
1084
1085 static void fuse_kill_sb_blk(struct super_block *sb)
1086 {
1087 struct fuse_conn *fc = get_fuse_conn_super(sb);
1088
1089 if (fc) {
1090 down_write(&fc->killsb);
1091 fc->sb = NULL;
1092 up_write(&fc->killsb);
1093 }
1094
1095 kill_block_super(sb);
1096 }
1097
1098 static struct file_system_type fuseblk_fs_type = {
1099 .owner = THIS_MODULE,
1100 .name = "fuseblk",
1101 .get_sb = fuse_get_sb_blk,
1102 .kill_sb = fuse_kill_sb_blk,
1103 .fs_flags = FS_REQUIRES_DEV | FS_HAS_SUBTYPE,
1104 };
1105
1106 static inline int register_fuseblk(void)
1107 {
1108 return register_filesystem(&fuseblk_fs_type);
1109 }
1110
1111 static inline void unregister_fuseblk(void)
1112 {
1113 unregister_filesystem(&fuseblk_fs_type);
1114 }
1115 #else
1116 static inline int register_fuseblk(void)
1117 {
1118 return 0;
1119 }
1120
1121 static inline void unregister_fuseblk(void)
1122 {
1123 }
1124 #endif
1125
1126 static void fuse_inode_init_once(void *foo)
1127 {
1128 struct inode *inode = foo;
1129
1130 inode_init_once(inode);
1131 }
1132
1133 static int __init fuse_fs_init(void)
1134 {
1135 int err;
1136
1137 err = register_filesystem(&fuse_fs_type);
1138 if (err)
1139 goto out;
1140
1141 err = register_fuseblk();
1142 if (err)
1143 goto out_unreg;
1144
1145 fuse_inode_cachep = kmem_cache_create("fuse_inode",
1146 sizeof(struct fuse_inode),
1147 0, SLAB_HWCACHE_ALIGN,
1148 fuse_inode_init_once);
1149 err = -ENOMEM;
1150 if (!fuse_inode_cachep)
1151 goto out_unreg2;
1152
1153 return 0;
1154
1155 out_unreg2:
1156 unregister_fuseblk();
1157 out_unreg:
1158 unregister_filesystem(&fuse_fs_type);
1159 out:
1160 return err;
1161 }
1162
1163 static void fuse_fs_cleanup(void)
1164 {
1165 unregister_filesystem(&fuse_fs_type);
1166 unregister_fuseblk();
1167 kmem_cache_destroy(fuse_inode_cachep);
1168 }
1169
1170 static struct kobject *fuse_kobj;
1171 static struct kobject *connections_kobj;
1172
1173 static int fuse_sysfs_init(void)
1174 {
1175 int err;
1176
1177 fuse_kobj = kobject_create_and_add("fuse", fs_kobj);
1178 if (!fuse_kobj) {
1179 err = -ENOMEM;
1180 goto out_err;
1181 }
1182
1183 connections_kobj = kobject_create_and_add("connections", fuse_kobj);
1184 if (!connections_kobj) {
1185 err = -ENOMEM;
1186 goto out_fuse_unregister;
1187 }
1188
1189 return 0;
1190
1191 out_fuse_unregister:
1192 kobject_put(fuse_kobj);
1193 out_err:
1194 return err;
1195 }
1196
1197 static void fuse_sysfs_cleanup(void)
1198 {
1199 kobject_put(connections_kobj);
1200 kobject_put(fuse_kobj);
1201 }
1202
1203 static int __init fuse_init(void)
1204 {
1205 int res;
1206
1207 printk(KERN_INFO "fuse init (API version %i.%i)\n",
1208 FUSE_KERNEL_VERSION, FUSE_KERNEL_MINOR_VERSION);
1209
1210 INIT_LIST_HEAD(&fuse_conn_list);
1211 res = fuse_fs_init();
1212 if (res)
1213 goto err;
1214
1215 res = fuse_dev_init();
1216 if (res)
1217 goto err_fs_cleanup;
1218
1219 res = fuse_sysfs_init();
1220 if (res)
1221 goto err_dev_cleanup;
1222
1223 res = fuse_ctl_init();
1224 if (res)
1225 goto err_sysfs_cleanup;
1226
1227 sanitize_global_limit(&max_user_bgreq);
1228 sanitize_global_limit(&max_user_congthresh);
1229
1230 return 0;
1231
1232 err_sysfs_cleanup:
1233 fuse_sysfs_cleanup();
1234 err_dev_cleanup:
1235 fuse_dev_cleanup();
1236 err_fs_cleanup:
1237 fuse_fs_cleanup();
1238 err:
1239 return res;
1240 }
1241
1242 static void __exit fuse_exit(void)
1243 {
1244 printk(KERN_DEBUG "fuse exit\n");
1245
1246 fuse_ctl_cleanup();
1247 fuse_sysfs_cleanup();
1248 fuse_fs_cleanup();
1249 fuse_dev_cleanup();
1250 }
1251
1252 module_init(fuse_init);
1253 module_exit(fuse_exit);
Linux kernel - Deliverables
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