2bab1b4ddf5ae506b0080157380dfed1edbfda4b
[linux-2.6.git] / fs / sysfs / dir.c
1 /*
2  * dir.c - Operations for sysfs directories.
3  */
4
5 #undef DEBUG
6
7 #include <linux/fs.h>
8 #include <linux/mount.h>
9 #include <linux/module.h>
10 #include <linux/kobject.h>
11 #include <linux/namei.h>
12 #include "sysfs.h"
13
14 DECLARE_RWSEM(sysfs_rename_sem);
15
16 static void sysfs_d_iput(struct dentry * dentry, struct inode * inode)
17 {
18         struct sysfs_dirent * sd = dentry->d_fsdata;
19
20         if (sd) {
21                 BUG_ON(sd->s_dentry != dentry);
22                 sd->s_dentry = NULL;
23                 sysfs_put(sd);
24         }
25         iput(inode);
26 }
27
28 static struct dentry_operations sysfs_dentry_ops = {
29         .d_iput         = sysfs_d_iput,
30 };
31
32 /*
33  * Allocates a new sysfs_dirent and links it to the parent sysfs_dirent
34  */
35 static struct sysfs_dirent * sysfs_new_dirent(struct sysfs_dirent * parent_sd,
36                                                 void * element)
37 {
38         struct sysfs_dirent * sd;
39
40         sd = kmem_cache_alloc(sysfs_dir_cachep, GFP_KERNEL);
41         if (!sd)
42                 return NULL;
43
44         memset(sd, 0, sizeof(*sd));
45         atomic_set(&sd->s_count, 1);
46         atomic_set(&sd->s_event, 1);
47         INIT_LIST_HEAD(&sd->s_children);
48         list_add(&sd->s_sibling, &parent_sd->s_children);
49         sd->s_element = element;
50
51         return sd;
52 }
53
54 /*
55  *
56  * Return -EEXIST if there is already a sysfs element with the same name for
57  * the same parent.
58  *
59  * called with parent inode's i_mutex held
60  */
61 int sysfs_dirent_exist(struct sysfs_dirent *parent_sd,
62                           const unsigned char *new)
63 {
64         struct sysfs_dirent * sd;
65
66         list_for_each_entry(sd, &parent_sd->s_children, s_sibling) {
67                 if (sd->s_element) {
68                         const unsigned char *existing = sysfs_get_name(sd);
69                         if (strcmp(existing, new))
70                                 continue;
71                         else
72                                 return -EEXIST;
73                 }
74         }
75
76         return 0;
77 }
78
79
80 int sysfs_make_dirent(struct sysfs_dirent * parent_sd, struct dentry * dentry,
81                         void * element, umode_t mode, int type)
82 {
83         struct sysfs_dirent * sd;
84
85         sd = sysfs_new_dirent(parent_sd, element);
86         if (!sd)
87                 return -ENOMEM;
88
89         sd->s_mode = mode;
90         sd->s_type = type;
91         sd->s_dentry = dentry;
92         if (dentry) {
93                 dentry->d_fsdata = sysfs_get(sd);
94                 dentry->d_op = &sysfs_dentry_ops;
95         }
96
97         return 0;
98 }
99
100 static int init_dir(struct inode * inode)
101 {
102         inode->i_op = &sysfs_dir_inode_operations;
103         inode->i_fop = &sysfs_dir_operations;
104
105         /* directory inodes start off with i_nlink == 2 (for "." entry) */
106         inc_nlink(inode);
107         return 0;
108 }
109
110 static int init_file(struct inode * inode)
111 {
112         inode->i_size = PAGE_SIZE;
113         inode->i_fop = &sysfs_file_operations;
114         return 0;
115 }
116
117 static int init_symlink(struct inode * inode)
118 {
119         inode->i_op = &sysfs_symlink_inode_operations;
120         return 0;
121 }
122
123 static int create_dir(struct kobject * k, struct dentry * p,
124                       const char * n, struct dentry ** d)
125 {
126         int error;
127         umode_t mode = S_IFDIR| S_IRWXU | S_IRUGO | S_IXUGO;
128
129         mutex_lock(&p->d_inode->i_mutex);
130         *d = lookup_one_len(n, p, strlen(n));
131         if (!IS_ERR(*d)) {
132                 if (sysfs_dirent_exist(p->d_fsdata, n))
133                         error = -EEXIST;
134                 else
135                         error = sysfs_make_dirent(p->d_fsdata, *d, k, mode,
136                                                                 SYSFS_DIR);
137                 if (!error) {
138                         error = sysfs_create(*d, mode, init_dir);
139                         if (!error) {
140                                 inc_nlink(p->d_inode);
141                                 (*d)->d_op = &sysfs_dentry_ops;
142                                 d_rehash(*d);
143                         }
144                 }
145                 if (error && (error != -EEXIST)) {
146                         struct sysfs_dirent *sd = (*d)->d_fsdata;
147                         if (sd) {
148                                 list_del_init(&sd->s_sibling);
149                                 sysfs_put(sd);
150                         }
151                         d_drop(*d);
152                 }
153                 dput(*d);
154         } else
155                 error = PTR_ERR(*d);
156         mutex_unlock(&p->d_inode->i_mutex);
157         return error;
158 }
159
160
161 int sysfs_create_subdir(struct kobject * k, const char * n, struct dentry ** d)
162 {
163         return create_dir(k,k->dentry,n,d);
164 }
165
166 /**
167  *      sysfs_create_dir - create a directory for an object.
168  *      @parent:        parent parent object.
169  *      @kobj:          object we're creating directory for. 
170  */
171
172 int sysfs_create_dir(struct kobject * kobj)
173 {
174         struct dentry * dentry = NULL;
175         struct dentry * parent;
176         int error = 0;
177
178         BUG_ON(!kobj);
179
180         if (kobj->parent)
181                 parent = kobj->parent->dentry;
182         else if (sysfs_mount && sysfs_mount->mnt_sb)
183                 parent = sysfs_mount->mnt_sb->s_root;
184         else
185                 return -EFAULT;
186
187         error = create_dir(kobj,parent,kobject_name(kobj),&dentry);
188         if (!error)
189                 kobj->dentry = dentry;
190         return error;
191 }
192
193 /* attaches attribute's sysfs_dirent to the dentry corresponding to the
194  * attribute file
195  */
196 static int sysfs_attach_attr(struct sysfs_dirent * sd, struct dentry * dentry)
197 {
198         struct attribute * attr = NULL;
199         struct bin_attribute * bin_attr = NULL;
200         int (* init) (struct inode *) = NULL;
201         int error = 0;
202
203         if (sd->s_type & SYSFS_KOBJ_BIN_ATTR) {
204                 bin_attr = sd->s_element;
205                 attr = &bin_attr->attr;
206         } else {
207                 attr = sd->s_element;
208                 init = init_file;
209         }
210
211         dentry->d_fsdata = sysfs_get(sd);
212         sd->s_dentry = dentry;
213         error = sysfs_create(dentry, (attr->mode & S_IALLUGO) | S_IFREG, init);
214         if (error) {
215                 sysfs_put(sd);
216                 return error;
217         }
218
219         if (bin_attr) {
220                 dentry->d_inode->i_size = bin_attr->size;
221                 dentry->d_inode->i_fop = &bin_fops;
222         }
223         dentry->d_op = &sysfs_dentry_ops;
224         d_rehash(dentry);
225
226         return 0;
227 }
228
229 static int sysfs_attach_link(struct sysfs_dirent * sd, struct dentry * dentry)
230 {
231         int err = 0;
232
233         dentry->d_fsdata = sysfs_get(sd);
234         sd->s_dentry = dentry;
235         err = sysfs_create(dentry, S_IFLNK|S_IRWXUGO, init_symlink);
236         if (!err) {
237                 dentry->d_op = &sysfs_dentry_ops;
238                 d_rehash(dentry);
239         } else
240                 sysfs_put(sd);
241
242         return err;
243 }
244
245 static struct dentry * sysfs_lookup(struct inode *dir, struct dentry *dentry,
246                                 struct nameidata *nd)
247 {
248         struct sysfs_dirent * parent_sd = dentry->d_parent->d_fsdata;
249         struct sysfs_dirent * sd;
250         int err = 0;
251
252         list_for_each_entry(sd, &parent_sd->s_children, s_sibling) {
253                 if (sd->s_type & SYSFS_NOT_PINNED) {
254                         const unsigned char * name = sysfs_get_name(sd);
255
256                         if (strcmp(name, dentry->d_name.name))
257                                 continue;
258
259                         if (sd->s_type & SYSFS_KOBJ_LINK)
260                                 err = sysfs_attach_link(sd, dentry);
261                         else
262                                 err = sysfs_attach_attr(sd, dentry);
263                         break;
264                 }
265         }
266
267         return ERR_PTR(err);
268 }
269
270 struct inode_operations sysfs_dir_inode_operations = {
271         .lookup         = sysfs_lookup,
272         .setattr        = sysfs_setattr,
273 };
274
275 static void remove_dir(struct dentry * d)
276 {
277         struct dentry * parent = dget(d->d_parent);
278         struct sysfs_dirent * sd;
279
280         mutex_lock(&parent->d_inode->i_mutex);
281         d_delete(d);
282         sd = d->d_fsdata;
283         list_del_init(&sd->s_sibling);
284         sysfs_put(sd);
285         if (d->d_inode)
286                 simple_rmdir(parent->d_inode,d);
287
288         pr_debug(" o %s removing done (%d)\n",d->d_name.name,
289                  atomic_read(&d->d_count));
290
291         mutex_unlock(&parent->d_inode->i_mutex);
292         dput(parent);
293 }
294
295 void sysfs_remove_subdir(struct dentry * d)
296 {
297         remove_dir(d);
298 }
299
300
301 /**
302  *      sysfs_remove_dir - remove an object's directory.
303  *      @kobj:  object. 
304  *
305  *      The only thing special about this is that we remove any files in 
306  *      the directory before we remove the directory, and we've inlined
307  *      what used to be sysfs_rmdir() below, instead of calling separately.
308  */
309
310 void sysfs_remove_dir(struct kobject * kobj)
311 {
312         struct dentry * dentry = dget(kobj->dentry);
313         struct sysfs_dirent * parent_sd;
314         struct sysfs_dirent * sd, * tmp;
315
316         if (!dentry)
317                 return;
318
319         pr_debug("sysfs %s: removing dir\n",dentry->d_name.name);
320         mutex_lock(&dentry->d_inode->i_mutex);
321         parent_sd = dentry->d_fsdata;
322         list_for_each_entry_safe(sd, tmp, &parent_sd->s_children, s_sibling) {
323                 if (!sd->s_element || !(sd->s_type & SYSFS_NOT_PINNED))
324                         continue;
325                 list_del_init(&sd->s_sibling);
326                 sysfs_drop_dentry(sd, dentry);
327                 sysfs_put(sd);
328         }
329         mutex_unlock(&dentry->d_inode->i_mutex);
330
331         remove_dir(dentry);
332         /**
333          * Drop reference from dget() on entrance.
334          */
335         dput(dentry);
336         kobj->dentry = NULL;
337 }
338
339 int sysfs_rename_dir(struct kobject * kobj, const char *new_name)
340 {
341         int error = 0;
342         struct dentry * new_dentry, * parent;
343
344         if (!strcmp(kobject_name(kobj), new_name))
345                 return -EINVAL;
346
347         if (!kobj->parent)
348                 return -EINVAL;
349
350         down_write(&sysfs_rename_sem);
351         parent = kobj->parent->dentry;
352
353         mutex_lock(&parent->d_inode->i_mutex);
354
355         new_dentry = lookup_one_len(new_name, parent, strlen(new_name));
356         if (!IS_ERR(new_dentry)) {
357                 if (!new_dentry->d_inode) {
358                         error = kobject_set_name(kobj, "%s", new_name);
359                         if (!error) {
360                                 d_add(new_dentry, NULL);
361                                 d_move(kobj->dentry, new_dentry);
362                         }
363                         else
364                                 d_drop(new_dentry);
365                 } else
366                         error = -EEXIST;
367                 dput(new_dentry);
368         }
369         mutex_unlock(&parent->d_inode->i_mutex);
370         up_write(&sysfs_rename_sem);
371
372         return error;
373 }
374
375 int sysfs_move_dir(struct kobject *kobj, struct kobject *new_parent)
376 {
377         struct dentry *old_parent_dentry, *new_parent_dentry, *new_dentry;
378         struct sysfs_dirent *new_parent_sd, *sd;
379         int error;
380
381         old_parent_dentry = kobj->parent ?
382                 kobj->parent->dentry : sysfs_mount->mnt_sb->s_root;
383         new_parent_dentry = new_parent ?
384                 new_parent->dentry : sysfs_mount->mnt_sb->s_root;
385
386 again:
387         mutex_lock(&old_parent_dentry->d_inode->i_mutex);
388         if (!mutex_trylock(&new_parent_dentry->d_inode->i_mutex)) {
389                 mutex_unlock(&old_parent_dentry->d_inode->i_mutex);
390                 goto again;
391         }
392
393         new_parent_sd = new_parent_dentry->d_fsdata;
394         sd = kobj->dentry->d_fsdata;
395
396         new_dentry = lookup_one_len(kobj->name, new_parent_dentry,
397                                     strlen(kobj->name));
398         if (IS_ERR(new_dentry)) {
399                 error = PTR_ERR(new_dentry);
400                 goto out;
401         } else
402                 error = 0;
403         d_add(new_dentry, NULL);
404         d_move(kobj->dentry, new_dentry);
405         dput(new_dentry);
406
407         /* Remove from old parent's list and insert into new parent's list. */
408         list_del_init(&sd->s_sibling);
409         list_add(&sd->s_sibling, &new_parent_sd->s_children);
410
411 out:
412         mutex_unlock(&new_parent_dentry->d_inode->i_mutex);
413         mutex_unlock(&old_parent_dentry->d_inode->i_mutex);
414
415         return error;
416 }
417
418 static int sysfs_dir_open(struct inode *inode, struct file *file)
419 {
420         struct dentry * dentry = file->f_path.dentry;
421         struct sysfs_dirent * parent_sd = dentry->d_fsdata;
422
423         mutex_lock(&dentry->d_inode->i_mutex);
424         file->private_data = sysfs_new_dirent(parent_sd, NULL);
425         mutex_unlock(&dentry->d_inode->i_mutex);
426
427         return file->private_data ? 0 : -ENOMEM;
428
429 }
430
431 static int sysfs_dir_close(struct inode *inode, struct file *file)
432 {
433         struct dentry * dentry = file->f_path.dentry;
434         struct sysfs_dirent * cursor = file->private_data;
435
436         mutex_lock(&dentry->d_inode->i_mutex);
437         list_del_init(&cursor->s_sibling);
438         mutex_unlock(&dentry->d_inode->i_mutex);
439
440         release_sysfs_dirent(cursor);
441
442         return 0;
443 }
444
445 /* Relationship between s_mode and the DT_xxx types */
446 static inline unsigned char dt_type(struct sysfs_dirent *sd)
447 {
448         return (sd->s_mode >> 12) & 15;
449 }
450
451 static int sysfs_readdir(struct file * filp, void * dirent, filldir_t filldir)
452 {
453         struct dentry *dentry = filp->f_path.dentry;
454         struct sysfs_dirent * parent_sd = dentry->d_fsdata;
455         struct sysfs_dirent *cursor = filp->private_data;
456         struct list_head *p, *q = &cursor->s_sibling;
457         ino_t ino;
458         int i = filp->f_pos;
459
460         switch (i) {
461                 case 0:
462                         ino = dentry->d_inode->i_ino;
463                         if (filldir(dirent, ".", 1, i, ino, DT_DIR) < 0)
464                                 break;
465                         filp->f_pos++;
466                         i++;
467                         /* fallthrough */
468                 case 1:
469                         ino = parent_ino(dentry);
470                         if (filldir(dirent, "..", 2, i, ino, DT_DIR) < 0)
471                                 break;
472                         filp->f_pos++;
473                         i++;
474                         /* fallthrough */
475                 default:
476                         if (filp->f_pos == 2)
477                                 list_move(q, &parent_sd->s_children);
478
479                         for (p=q->next; p!= &parent_sd->s_children; p=p->next) {
480                                 struct sysfs_dirent *next;
481                                 const char * name;
482                                 int len;
483
484                                 next = list_entry(p, struct sysfs_dirent,
485                                                    s_sibling);
486                                 if (!next->s_element)
487                                         continue;
488
489                                 name = sysfs_get_name(next);
490                                 len = strlen(name);
491                                 if (next->s_dentry)
492                                         ino = next->s_dentry->d_inode->i_ino;
493                                 else
494                                         ino = iunique(sysfs_sb, 2);
495
496                                 if (filldir(dirent, name, len, filp->f_pos, ino,
497                                                  dt_type(next)) < 0)
498                                         return 0;
499
500                                 list_move(q, p);
501                                 p = q;
502                                 filp->f_pos++;
503                         }
504         }
505         return 0;
506 }
507
508 static loff_t sysfs_dir_lseek(struct file * file, loff_t offset, int origin)
509 {
510         struct dentry * dentry = file->f_path.dentry;
511
512         mutex_lock(&dentry->d_inode->i_mutex);
513         switch (origin) {
514                 case 1:
515                         offset += file->f_pos;
516                 case 0:
517                         if (offset >= 0)
518                                 break;
519                 default:
520                         mutex_unlock(&file->f_path.dentry->d_inode->i_mutex);
521                         return -EINVAL;
522         }
523         if (offset != file->f_pos) {
524                 file->f_pos = offset;
525                 if (file->f_pos >= 2) {
526                         struct sysfs_dirent *sd = dentry->d_fsdata;
527                         struct sysfs_dirent *cursor = file->private_data;
528                         struct list_head *p;
529                         loff_t n = file->f_pos - 2;
530
531                         list_del(&cursor->s_sibling);
532                         p = sd->s_children.next;
533                         while (n && p != &sd->s_children) {
534                                 struct sysfs_dirent *next;
535                                 next = list_entry(p, struct sysfs_dirent,
536                                                    s_sibling);
537                                 if (next->s_element)
538                                         n--;
539                                 p = p->next;
540                         }
541                         list_add_tail(&cursor->s_sibling, p);
542                 }
543         }
544         mutex_unlock(&dentry->d_inode->i_mutex);
545         return offset;
546 }
547
548 const struct file_operations sysfs_dir_operations = {
549         .open           = sysfs_dir_open,
550         .release        = sysfs_dir_close,
551         .llseek         = sysfs_dir_lseek,
552         .read           = generic_read_dir,
553         .readdir        = sysfs_readdir,
554 };