[PATCH] fuse: add number of waiting requests attribute
[linux-2.6] / fs / fuse / inode.c
1 /*
2   FUSE: Filesystem in Userspace
3   Copyright (C) 2001-2005  Miklos Szeredi <miklos@szeredi.hu>
4
5   This program can be distributed under the terms of the GNU GPL.
6   See the file COPYING.
7 */
8
9 #include "fuse_i.h"
10
11 #include <linux/pagemap.h>
12 #include <linux/slab.h>
13 #include <linux/file.h>
14 #include <linux/mount.h>
15 #include <linux/seq_file.h>
16 #include <linux/init.h>
17 #include <linux/module.h>
18 #include <linux/parser.h>
19 #include <linux/statfs.h>
20
21 MODULE_AUTHOR("Miklos Szeredi <miklos@szeredi.hu>");
22 MODULE_DESCRIPTION("Filesystem in Userspace");
23 MODULE_LICENSE("GPL");
24
25 spinlock_t fuse_lock;
26 static kmem_cache_t *fuse_inode_cachep;
27 static struct subsystem connections_subsys;
28
29 struct fuse_conn_attr {
30         struct attribute attr;
31         ssize_t (*show)(struct fuse_conn *, char *);
32         ssize_t (*store)(struct fuse_conn *, const char *, size_t);
33 };
34
35 #define FUSE_SUPER_MAGIC 0x65735546
36
37 struct fuse_mount_data {
38         int fd;
39         unsigned rootmode;
40         unsigned user_id;
41         unsigned group_id;
42         unsigned fd_present : 1;
43         unsigned rootmode_present : 1;
44         unsigned user_id_present : 1;
45         unsigned group_id_present : 1;
46         unsigned flags;
47         unsigned max_read;
48 };
49
50 static struct inode *fuse_alloc_inode(struct super_block *sb)
51 {
52         struct inode *inode;
53         struct fuse_inode *fi;
54
55         inode = kmem_cache_alloc(fuse_inode_cachep, SLAB_KERNEL);
56         if (!inode)
57                 return NULL;
58
59         fi = get_fuse_inode(inode);
60         fi->i_time = jiffies - 1;
61         fi->nodeid = 0;
62         fi->nlookup = 0;
63         fi->forget_req = fuse_request_alloc();
64         if (!fi->forget_req) {
65                 kmem_cache_free(fuse_inode_cachep, inode);
66                 return NULL;
67         }
68
69         return inode;
70 }
71
72 static void fuse_destroy_inode(struct inode *inode)
73 {
74         struct fuse_inode *fi = get_fuse_inode(inode);
75         if (fi->forget_req)
76                 fuse_request_free(fi->forget_req);
77         kmem_cache_free(fuse_inode_cachep, inode);
78 }
79
80 static void fuse_read_inode(struct inode *inode)
81 {
82         /* No op */
83 }
84
85 void fuse_send_forget(struct fuse_conn *fc, struct fuse_req *req,
86                       unsigned long nodeid, u64 nlookup)
87 {
88         struct fuse_forget_in *inarg = &req->misc.forget_in;
89         inarg->nlookup = nlookup;
90         req->in.h.opcode = FUSE_FORGET;
91         req->in.h.nodeid = nodeid;
92         req->in.numargs = 1;
93         req->in.args[0].size = sizeof(struct fuse_forget_in);
94         req->in.args[0].value = inarg;
95         request_send_noreply(fc, req);
96 }
97
98 static void fuse_clear_inode(struct inode *inode)
99 {
100         if (inode->i_sb->s_flags & MS_ACTIVE) {
101                 struct fuse_conn *fc = get_fuse_conn(inode);
102                 struct fuse_inode *fi = get_fuse_inode(inode);
103                 fuse_send_forget(fc, fi->forget_req, fi->nodeid, fi->nlookup);
104                 fi->forget_req = NULL;
105         }
106 }
107
108 void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr)
109 {
110         if (S_ISREG(inode->i_mode) && i_size_read(inode) != attr->size)
111                 invalidate_inode_pages(inode->i_mapping);
112
113         inode->i_ino     = attr->ino;
114         inode->i_mode    = (inode->i_mode & S_IFMT) + (attr->mode & 07777);
115         inode->i_nlink   = attr->nlink;
116         inode->i_uid     = attr->uid;
117         inode->i_gid     = attr->gid;
118         i_size_write(inode, attr->size);
119         inode->i_blksize = PAGE_CACHE_SIZE;
120         inode->i_blocks  = attr->blocks;
121         inode->i_atime.tv_sec   = attr->atime;
122         inode->i_atime.tv_nsec  = attr->atimensec;
123         inode->i_mtime.tv_sec   = attr->mtime;
124         inode->i_mtime.tv_nsec  = attr->mtimensec;
125         inode->i_ctime.tv_sec   = attr->ctime;
126         inode->i_ctime.tv_nsec  = attr->ctimensec;
127 }
128
129 static void fuse_init_inode(struct inode *inode, struct fuse_attr *attr)
130 {
131         inode->i_mode = attr->mode & S_IFMT;
132         i_size_write(inode, attr->size);
133         if (S_ISREG(inode->i_mode)) {
134                 fuse_init_common(inode);
135                 fuse_init_file_inode(inode);
136         } else if (S_ISDIR(inode->i_mode))
137                 fuse_init_dir(inode);
138         else if (S_ISLNK(inode->i_mode))
139                 fuse_init_symlink(inode);
140         else if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode) ||
141                  S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode)) {
142                 fuse_init_common(inode);
143                 init_special_inode(inode, inode->i_mode,
144                                    new_decode_dev(attr->rdev));
145         } else
146                 BUG();
147 }
148
149 static int fuse_inode_eq(struct inode *inode, void *_nodeidp)
150 {
151         unsigned long nodeid = *(unsigned long *) _nodeidp;
152         if (get_node_id(inode) == nodeid)
153                 return 1;
154         else
155                 return 0;
156 }
157
158 static int fuse_inode_set(struct inode *inode, void *_nodeidp)
159 {
160         unsigned long nodeid = *(unsigned long *) _nodeidp;
161         get_fuse_inode(inode)->nodeid = nodeid;
162         return 0;
163 }
164
165 struct inode *fuse_iget(struct super_block *sb, unsigned long nodeid,
166                         int generation, struct fuse_attr *attr)
167 {
168         struct inode *inode;
169         struct fuse_inode *fi;
170         struct fuse_conn *fc = get_fuse_conn_super(sb);
171         int retried = 0;
172
173  retry:
174         inode = iget5_locked(sb, nodeid, fuse_inode_eq, fuse_inode_set, &nodeid);
175         if (!inode)
176                 return NULL;
177
178         if ((inode->i_state & I_NEW)) {
179                 inode->i_flags |= S_NOATIME|S_NOCMTIME;
180                 inode->i_generation = generation;
181                 inode->i_data.backing_dev_info = &fc->bdi;
182                 fuse_init_inode(inode, attr);
183                 unlock_new_inode(inode);
184         } else if ((inode->i_mode ^ attr->mode) & S_IFMT) {
185                 BUG_ON(retried);
186                 /* Inode has changed type, any I/O on the old should fail */
187                 make_bad_inode(inode);
188                 iput(inode);
189                 retried = 1;
190                 goto retry;
191         }
192
193         fi = get_fuse_inode(inode);
194         fi->nlookup ++;
195         fuse_change_attributes(inode, attr);
196         return inode;
197 }
198
199 static void fuse_put_super(struct super_block *sb)
200 {
201         struct fuse_conn *fc = get_fuse_conn_super(sb);
202
203         down_write(&fc->sbput_sem);
204         while (!list_empty(&fc->background))
205                 fuse_release_background(list_entry(fc->background.next,
206                                                    struct fuse_req, bg_entry));
207
208         spin_lock(&fuse_lock);
209         fc->mounted = 0;
210         fc->connected = 0;
211         spin_unlock(&fuse_lock);
212         up_write(&fc->sbput_sem);
213         /* Flush all readers on this fs */
214         wake_up_all(&fc->waitq);
215         kobject_del(&fc->kobj);
216         kobject_put(&fc->kobj);
217 }
218
219 static void convert_fuse_statfs(struct kstatfs *stbuf, struct fuse_kstatfs *attr)
220 {
221         stbuf->f_type    = FUSE_SUPER_MAGIC;
222         stbuf->f_bsize   = attr->bsize;
223         stbuf->f_frsize  = attr->frsize;
224         stbuf->f_blocks  = attr->blocks;
225         stbuf->f_bfree   = attr->bfree;
226         stbuf->f_bavail  = attr->bavail;
227         stbuf->f_files   = attr->files;
228         stbuf->f_ffree   = attr->ffree;
229         stbuf->f_namelen = attr->namelen;
230         /* fsid is left zero */
231 }
232
233 static int fuse_statfs(struct super_block *sb, struct kstatfs *buf)
234 {
235         struct fuse_conn *fc = get_fuse_conn_super(sb);
236         struct fuse_req *req;
237         struct fuse_statfs_out outarg;
238         int err;
239
240         req = fuse_get_request(fc);
241         if (!req)
242                 return -EINTR;
243
244         memset(&outarg, 0, sizeof(outarg));
245         req->in.numargs = 0;
246         req->in.h.opcode = FUSE_STATFS;
247         req->out.numargs = 1;
248         req->out.args[0].size =
249                 fc->minor < 4 ? FUSE_COMPAT_STATFS_SIZE : sizeof(outarg);
250         req->out.args[0].value = &outarg;
251         request_send(fc, req);
252         err = req->out.h.error;
253         if (!err)
254                 convert_fuse_statfs(buf, &outarg.st);
255         fuse_put_request(fc, req);
256         return err;
257 }
258
259 enum {
260         OPT_FD,
261         OPT_ROOTMODE,
262         OPT_USER_ID,
263         OPT_GROUP_ID,
264         OPT_DEFAULT_PERMISSIONS,
265         OPT_ALLOW_OTHER,
266         OPT_MAX_READ,
267         OPT_ERR
268 };
269
270 static match_table_t tokens = {
271         {OPT_FD,                        "fd=%u"},
272         {OPT_ROOTMODE,                  "rootmode=%o"},
273         {OPT_USER_ID,                   "user_id=%u"},
274         {OPT_GROUP_ID,                  "group_id=%u"},
275         {OPT_DEFAULT_PERMISSIONS,       "default_permissions"},
276         {OPT_ALLOW_OTHER,               "allow_other"},
277         {OPT_MAX_READ,                  "max_read=%u"},
278         {OPT_ERR,                       NULL}
279 };
280
281 static int parse_fuse_opt(char *opt, struct fuse_mount_data *d)
282 {
283         char *p;
284         memset(d, 0, sizeof(struct fuse_mount_data));
285         d->max_read = ~0;
286
287         while ((p = strsep(&opt, ",")) != NULL) {
288                 int token;
289                 int value;
290                 substring_t args[MAX_OPT_ARGS];
291                 if (!*p)
292                         continue;
293
294                 token = match_token(p, tokens, args);
295                 switch (token) {
296                 case OPT_FD:
297                         if (match_int(&args[0], &value))
298                                 return 0;
299                         d->fd = value;
300                         d->fd_present = 1;
301                         break;
302
303                 case OPT_ROOTMODE:
304                         if (match_octal(&args[0], &value))
305                                 return 0;
306                         d->rootmode = value;
307                         d->rootmode_present = 1;
308                         break;
309
310                 case OPT_USER_ID:
311                         if (match_int(&args[0], &value))
312                                 return 0;
313                         d->user_id = value;
314                         d->user_id_present = 1;
315                         break;
316
317                 case OPT_GROUP_ID:
318                         if (match_int(&args[0], &value))
319                                 return 0;
320                         d->group_id = value;
321                         d->group_id_present = 1;
322                         break;
323
324                 case OPT_DEFAULT_PERMISSIONS:
325                         d->flags |= FUSE_DEFAULT_PERMISSIONS;
326                         break;
327
328                 case OPT_ALLOW_OTHER:
329                         d->flags |= FUSE_ALLOW_OTHER;
330                         break;
331
332                 case OPT_MAX_READ:
333                         if (match_int(&args[0], &value))
334                                 return 0;
335                         d->max_read = value;
336                         break;
337
338                 default:
339                         return 0;
340                 }
341         }
342
343         if (!d->fd_present || !d->rootmode_present ||
344             !d->user_id_present || !d->group_id_present)
345                 return 0;
346
347         return 1;
348 }
349
350 static int fuse_show_options(struct seq_file *m, struct vfsmount *mnt)
351 {
352         struct fuse_conn *fc = get_fuse_conn_super(mnt->mnt_sb);
353
354         seq_printf(m, ",user_id=%u", fc->user_id);
355         seq_printf(m, ",group_id=%u", fc->group_id);
356         if (fc->flags & FUSE_DEFAULT_PERMISSIONS)
357                 seq_puts(m, ",default_permissions");
358         if (fc->flags & FUSE_ALLOW_OTHER)
359                 seq_puts(m, ",allow_other");
360         if (fc->max_read != ~0)
361                 seq_printf(m, ",max_read=%u", fc->max_read);
362         return 0;
363 }
364
365 static void fuse_conn_release(struct kobject *kobj)
366 {
367         struct fuse_conn *fc = get_fuse_conn_kobj(kobj);
368
369         while (!list_empty(&fc->unused_list)) {
370                 struct fuse_req *req;
371                 req = list_entry(fc->unused_list.next, struct fuse_req, list);
372                 list_del(&req->list);
373                 fuse_request_free(req);
374         }
375         kfree(fc);
376 }
377
378 static struct fuse_conn *new_conn(void)
379 {
380         struct fuse_conn *fc;
381
382         fc = kzalloc(sizeof(*fc), GFP_KERNEL);
383         if (fc) {
384                 int i;
385                 init_waitqueue_head(&fc->waitq);
386                 INIT_LIST_HEAD(&fc->pending);
387                 INIT_LIST_HEAD(&fc->processing);
388                 INIT_LIST_HEAD(&fc->io);
389                 INIT_LIST_HEAD(&fc->unused_list);
390                 INIT_LIST_HEAD(&fc->background);
391                 sema_init(&fc->outstanding_sem, 1); /* One for INIT */
392                 init_rwsem(&fc->sbput_sem);
393                 kobj_set_kset_s(fc, connections_subsys);
394                 kobject_init(&fc->kobj);
395                 for (i = 0; i < FUSE_MAX_OUTSTANDING; i++) {
396                         struct fuse_req *req = fuse_request_alloc();
397                         if (!req) {
398                                 kobject_put(&fc->kobj);
399                                 return NULL;
400                         }
401                         list_add(&req->list, &fc->unused_list);
402                 }
403                 fc->bdi.ra_pages = (VM_MAX_READAHEAD * 1024) / PAGE_CACHE_SIZE;
404                 fc->bdi.unplug_io_fn = default_unplug_io_fn;
405                 fc->reqctr = 0;
406         }
407         return fc;
408 }
409
410 static struct fuse_conn *get_conn(struct file *file, struct super_block *sb)
411 {
412         struct fuse_conn *fc;
413         int err;
414
415         err = -EINVAL;
416         if (file->f_op != &fuse_dev_operations)
417                 goto out_err;
418
419         err = -ENOMEM;
420         fc = new_conn();
421         if (!fc)
422                 goto out_err;
423
424         spin_lock(&fuse_lock);
425         err = -EINVAL;
426         if (file->private_data)
427                 goto out_unlock;
428
429         kobject_get(&fc->kobj);
430         file->private_data = fc;
431         spin_unlock(&fuse_lock);
432         return fc;
433
434  out_unlock:
435         spin_unlock(&fuse_lock);
436         kobject_put(&fc->kobj);
437  out_err:
438         return ERR_PTR(err);
439 }
440
441 static struct inode *get_root_inode(struct super_block *sb, unsigned mode)
442 {
443         struct fuse_attr attr;
444         memset(&attr, 0, sizeof(attr));
445
446         attr.mode = mode;
447         attr.ino = FUSE_ROOT_ID;
448         return fuse_iget(sb, 1, 0, &attr);
449 }
450
451 static struct super_operations fuse_super_operations = {
452         .alloc_inode    = fuse_alloc_inode,
453         .destroy_inode  = fuse_destroy_inode,
454         .read_inode     = fuse_read_inode,
455         .clear_inode    = fuse_clear_inode,
456         .put_super      = fuse_put_super,
457         .statfs         = fuse_statfs,
458         .show_options   = fuse_show_options,
459 };
460
461 static unsigned long long conn_id(void)
462 {
463         static unsigned long long ctr = 1;
464         unsigned long long val;
465         spin_lock(&fuse_lock);
466         val = ctr++;
467         spin_unlock(&fuse_lock);
468         return val;
469 }
470
471 static int fuse_fill_super(struct super_block *sb, void *data, int silent)
472 {
473         struct fuse_conn *fc;
474         struct inode *root;
475         struct fuse_mount_data d;
476         struct file *file;
477         struct dentry *root_dentry;
478         int err;
479
480         if (!parse_fuse_opt((char *) data, &d))
481                 return -EINVAL;
482
483         sb->s_blocksize = PAGE_CACHE_SIZE;
484         sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
485         sb->s_magic = FUSE_SUPER_MAGIC;
486         sb->s_op = &fuse_super_operations;
487         sb->s_maxbytes = MAX_LFS_FILESIZE;
488
489         file = fget(d.fd);
490         if (!file)
491                 return -EINVAL;
492
493         fc = get_conn(file, sb);
494         fput(file);
495         if (IS_ERR(fc))
496                 return PTR_ERR(fc);
497
498         fc->flags = d.flags;
499         fc->user_id = d.user_id;
500         fc->group_id = d.group_id;
501         fc->max_read = d.max_read;
502         if (fc->max_read / PAGE_CACHE_SIZE < fc->bdi.ra_pages)
503                 fc->bdi.ra_pages = fc->max_read / PAGE_CACHE_SIZE;
504
505         /* Used by get_root_inode() */
506         sb->s_fs_info = fc;
507
508         err = -ENOMEM;
509         root = get_root_inode(sb, d.rootmode);
510         if (!root)
511                 goto err;
512
513         root_dentry = d_alloc_root(root);
514         if (!root_dentry) {
515                 iput(root);
516                 goto err;
517         }
518
519         err = kobject_set_name(&fc->kobj, "%llu", conn_id());
520         if (err)
521                 goto err_put_root;
522
523         err = kobject_add(&fc->kobj);
524         if (err)
525                 goto err_put_root;
526
527         sb->s_root = root_dentry;
528         spin_lock(&fuse_lock);
529         fc->mounted = 1;
530         fc->connected = 1;
531         spin_unlock(&fuse_lock);
532
533         fuse_send_init(fc);
534
535         return 0;
536
537  err_put_root:
538         dput(root_dentry);
539  err:
540         kobject_put(&fc->kobj);
541         return err;
542 }
543
544 static struct super_block *fuse_get_sb(struct file_system_type *fs_type,
545                                        int flags, const char *dev_name,
546                                        void *raw_data)
547 {
548         return get_sb_nodev(fs_type, flags, raw_data, fuse_fill_super);
549 }
550
551 static struct file_system_type fuse_fs_type = {
552         .owner          = THIS_MODULE,
553         .name           = "fuse",
554         .get_sb         = fuse_get_sb,
555         .kill_sb        = kill_anon_super,
556 };
557
558 static ssize_t fuse_conn_waiting_show(struct fuse_conn *fc, char *page)
559 {
560         return sprintf(page, "%i\n", atomic_read(&fc->num_waiting));
561 }
562
563 static struct fuse_conn_attr fuse_conn_waiting =
564         __ATTR(waiting, 0400, fuse_conn_waiting_show, NULL);
565
566 static struct attribute *fuse_conn_attrs[] = {
567         &fuse_conn_waiting.attr,
568         NULL,
569 };
570
571 static ssize_t fuse_conn_attr_show(struct kobject *kobj,
572                                    struct attribute *attr,
573                                    char *page)
574 {
575         struct fuse_conn_attr *fca =
576                 container_of(attr, struct fuse_conn_attr, attr);
577
578         if (fca->show)
579                 return fca->show(get_fuse_conn_kobj(kobj), page);
580         else
581                 return -EACCES;
582 }
583
584 static ssize_t fuse_conn_attr_store(struct kobject *kobj,
585                                     struct attribute *attr,
586                                     const char *page, size_t count)
587 {
588         struct fuse_conn_attr *fca =
589                 container_of(attr, struct fuse_conn_attr, attr);
590
591         if (fca->store)
592                 return fca->store(get_fuse_conn_kobj(kobj), page, count);
593         else
594                 return -EACCES;
595 }
596
597 static struct sysfs_ops fuse_conn_sysfs_ops = {
598         .show   = &fuse_conn_attr_show,
599         .store  = &fuse_conn_attr_store,
600 };
601
602 static struct kobj_type ktype_fuse_conn = {
603         .release        = fuse_conn_release,
604         .sysfs_ops      = &fuse_conn_sysfs_ops,
605         .default_attrs  = fuse_conn_attrs,
606 };
607
608 static decl_subsys(fuse, NULL, NULL);
609 static decl_subsys(connections, &ktype_fuse_conn, NULL);
610
611 static void fuse_inode_init_once(void *foo, kmem_cache_t *cachep,
612                                  unsigned long flags)
613 {
614         struct inode * inode = foo;
615
616         if ((flags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) ==
617             SLAB_CTOR_CONSTRUCTOR)
618                 inode_init_once(inode);
619 }
620
621 static int __init fuse_fs_init(void)
622 {
623         int err;
624
625         err = register_filesystem(&fuse_fs_type);
626         if (err)
627                 printk("fuse: failed to register filesystem\n");
628         else {
629                 fuse_inode_cachep = kmem_cache_create("fuse_inode",
630                                                       sizeof(struct fuse_inode),
631                                                       0, SLAB_HWCACHE_ALIGN,
632                                                       fuse_inode_init_once, NULL);
633                 if (!fuse_inode_cachep) {
634                         unregister_filesystem(&fuse_fs_type);
635                         err = -ENOMEM;
636                 }
637         }
638
639         return err;
640 }
641
642 static void fuse_fs_cleanup(void)
643 {
644         unregister_filesystem(&fuse_fs_type);
645         kmem_cache_destroy(fuse_inode_cachep);
646 }
647
648 static int fuse_sysfs_init(void)
649 {
650         int err;
651
652         kset_set_kset_s(&fuse_subsys, fs_subsys);
653         err = subsystem_register(&fuse_subsys);
654         if (err)
655                 goto out_err;
656
657         kset_set_kset_s(&connections_subsys, fuse_subsys);
658         err = subsystem_register(&connections_subsys);
659         if (err)
660                 goto out_fuse_unregister;
661
662         return 0;
663
664  out_fuse_unregister:
665         subsystem_unregister(&fuse_subsys);
666  out_err:
667         return err;
668 }
669
670 static void fuse_sysfs_cleanup(void)
671 {
672         subsystem_unregister(&connections_subsys);
673         subsystem_unregister(&fuse_subsys);
674 }
675
676 static int __init fuse_init(void)
677 {
678         int res;
679
680         printk("fuse init (API version %i.%i)\n",
681                FUSE_KERNEL_VERSION, FUSE_KERNEL_MINOR_VERSION);
682
683         spin_lock_init(&fuse_lock);
684         res = fuse_fs_init();
685         if (res)
686                 goto err;
687
688         res = fuse_dev_init();
689         if (res)
690                 goto err_fs_cleanup;
691
692         res = fuse_sysfs_init();
693         if (res)
694                 goto err_dev_cleanup;
695
696         return 0;
697
698  err_dev_cleanup:
699         fuse_dev_cleanup();
700  err_fs_cleanup:
701         fuse_fs_cleanup();
702  err:
703         return res;
704 }
705
706 static void __exit fuse_exit(void)
707 {
708         printk(KERN_DEBUG "fuse exit\n");
709
710         fuse_sysfs_cleanup();
711         fuse_fs_cleanup();
712         fuse_dev_cleanup();
713 }
714
715 module_init(fuse_init);
716 module_exit(fuse_exit);