37d7a6875d86908556726b070782b13ba87eb5ae
[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 "sysfs.h"
12
13 DECLARE_RWSEM(sysfs_rename_sem);
14
15 static void sysfs_d_iput(struct dentry * dentry, struct inode * inode)
16 {
17         struct sysfs_dirent * sd = dentry->d_fsdata;
18
19         if (sd) {
20                 BUG_ON(sd->s_dentry != dentry);
21                 sd->s_dentry = NULL;
22                 sysfs_put(sd);
23         }
24         iput(inode);
25 }
26
27 static struct dentry_operations sysfs_dentry_ops = {
28         .d_iput         = sysfs_d_iput,
29 };
30
31 /*
32  * Allocates a new sysfs_dirent and links it to the parent sysfs_dirent
33  */
34 static struct sysfs_dirent * sysfs_new_dirent(struct sysfs_dirent * parent_sd,
35                                                 void * element)
36 {
37         struct sysfs_dirent * sd;
38
39         sd = kmem_cache_alloc(sysfs_dir_cachep, GFP_KERNEL);
40         if (!sd)
41                 return NULL;
42
43         memset(sd, 0, sizeof(*sd));
44         atomic_set(&sd->s_count, 1);
45         INIT_LIST_HEAD(&sd->s_children);
46         list_add(&sd->s_sibling, &parent_sd->s_children);
47         sd->s_element = element;
48
49         return sd;
50 }
51
52 int sysfs_make_dirent(struct sysfs_dirent * parent_sd, struct dentry * dentry,
53                         void * element, umode_t mode, int type)
54 {
55         struct sysfs_dirent * sd;
56
57         sd = sysfs_new_dirent(parent_sd, element);
58         if (!sd)
59                 return -ENOMEM;
60
61         sd->s_mode = mode;
62         sd->s_type = type;
63         sd->s_dentry = dentry;
64         if (dentry) {
65                 dentry->d_fsdata = sysfs_get(sd);
66                 dentry->d_op = &sysfs_dentry_ops;
67         }
68
69         return 0;
70 }
71
72 static int init_dir(struct inode * inode)
73 {
74         inode->i_op = &sysfs_dir_inode_operations;
75         inode->i_fop = &sysfs_dir_operations;
76
77         /* directory inodes start off with i_nlink == 2 (for "." entry) */
78         inode->i_nlink++;
79         return 0;
80 }
81
82 static int init_file(struct inode * inode)
83 {
84         inode->i_size = PAGE_SIZE;
85         inode->i_fop = &sysfs_file_operations;
86         return 0;
87 }
88
89 static int init_symlink(struct inode * inode)
90 {
91         inode->i_op = &sysfs_symlink_inode_operations;
92         return 0;
93 }
94
95 static int create_dir(struct kobject * k, struct dentry * p,
96                       const char * n, struct dentry ** d)
97 {
98         int error;
99         umode_t mode = S_IFDIR| S_IRWXU | S_IRUGO | S_IXUGO;
100
101         down(&p->d_inode->i_sem);
102         *d = sysfs_get_dentry(p,n);
103         if (!IS_ERR(*d)) {
104                 error = sysfs_make_dirent(p->d_fsdata, *d, k, mode, SYSFS_DIR);
105                 if (!error) {
106                         error = sysfs_create(*d, mode, init_dir);
107                         if (!error) {
108                                 p->d_inode->i_nlink++;
109                                 (*d)->d_op = &sysfs_dentry_ops;
110                                 d_rehash(*d);
111                         }
112                 }
113                 if (error && (error != -EEXIST)) {
114                         sysfs_put((*d)->d_fsdata);
115                         d_drop(*d);
116                 }
117                 dput(*d);
118         } else
119                 error = PTR_ERR(*d);
120         up(&p->d_inode->i_sem);
121         return error;
122 }
123
124
125 int sysfs_create_subdir(struct kobject * k, const char * n, struct dentry ** d)
126 {
127         return create_dir(k,k->dentry,n,d);
128 }
129
130 /**
131  *      sysfs_create_dir - create a directory for an object.
132  *      @parent:        parent parent object.
133  *      @kobj:          object we're creating directory for. 
134  */
135
136 int sysfs_create_dir(struct kobject * kobj)
137 {
138         struct dentry * dentry = NULL;
139         struct dentry * parent;
140         int error = 0;
141
142         BUG_ON(!kobj);
143
144         if (kobj->parent)
145                 parent = kobj->parent->dentry;
146         else if (sysfs_mount && sysfs_mount->mnt_sb)
147                 parent = sysfs_mount->mnt_sb->s_root;
148         else
149                 return -EFAULT;
150
151         error = create_dir(kobj,parent,kobject_name(kobj),&dentry);
152         if (!error)
153                 kobj->dentry = dentry;
154         return error;
155 }
156
157 /* attaches attribute's sysfs_dirent to the dentry corresponding to the
158  * attribute file
159  */
160 static int sysfs_attach_attr(struct sysfs_dirent * sd, struct dentry * dentry)
161 {
162         struct attribute * attr = NULL;
163         struct bin_attribute * bin_attr = NULL;
164         int (* init) (struct inode *) = NULL;
165         int error = 0;
166
167         if (sd->s_type & SYSFS_KOBJ_BIN_ATTR) {
168                 bin_attr = sd->s_element;
169                 attr = &bin_attr->attr;
170         } else {
171                 attr = sd->s_element;
172                 init = init_file;
173         }
174
175         dentry->d_fsdata = sysfs_get(sd);
176         sd->s_dentry = dentry;
177         error = sysfs_create(dentry, (attr->mode & S_IALLUGO) | S_IFREG, init);
178         if (error) {
179                 sysfs_put(sd);
180                 return error;
181         }
182
183         if (bin_attr) {
184                 dentry->d_inode->i_size = bin_attr->size;
185                 dentry->d_inode->i_fop = &bin_fops;
186         }
187         dentry->d_op = &sysfs_dentry_ops;
188         d_rehash(dentry);
189
190         return 0;
191 }
192
193 static int sysfs_attach_link(struct sysfs_dirent * sd, struct dentry * dentry)
194 {
195         int err = 0;
196
197         dentry->d_fsdata = sysfs_get(sd);
198         sd->s_dentry = dentry;
199         err = sysfs_create(dentry, S_IFLNK|S_IRWXUGO, init_symlink);
200         if (!err) {
201                 dentry->d_op = &sysfs_dentry_ops;
202                 d_rehash(dentry);
203         } else
204                 sysfs_put(sd);
205
206         return err;
207 }
208
209 static struct dentry * sysfs_lookup(struct inode *dir, struct dentry *dentry,
210                                 struct nameidata *nd)
211 {
212         struct sysfs_dirent * parent_sd = dentry->d_parent->d_fsdata;
213         struct sysfs_dirent * sd;
214         int err = 0;
215
216         list_for_each_entry(sd, &parent_sd->s_children, s_sibling) {
217                 if (sd->s_type & SYSFS_NOT_PINNED) {
218                         const unsigned char * name = sysfs_get_name(sd);
219
220                         if (strcmp(name, dentry->d_name.name))
221                                 continue;
222
223                         if (sd->s_type & SYSFS_KOBJ_LINK)
224                                 err = sysfs_attach_link(sd, dentry);
225                         else
226                                 err = sysfs_attach_attr(sd, dentry);
227                         break;
228                 }
229         }
230
231         return ERR_PTR(err);
232 }
233
234 struct inode_operations sysfs_dir_inode_operations = {
235         .lookup         = sysfs_lookup,
236         .setattr        = sysfs_setattr,
237 };
238
239 static void remove_dir(struct dentry * d)
240 {
241         struct dentry * parent = dget(d->d_parent);
242         struct sysfs_dirent * sd;
243
244         down(&parent->d_inode->i_sem);
245         d_delete(d);
246         sd = d->d_fsdata;
247         list_del_init(&sd->s_sibling);
248         sysfs_put(sd);
249         if (d->d_inode)
250                 simple_rmdir(parent->d_inode,d);
251
252         pr_debug(" o %s removing done (%d)\n",d->d_name.name,
253                  atomic_read(&d->d_count));
254
255         up(&parent->d_inode->i_sem);
256         dput(parent);
257 }
258
259 void sysfs_remove_subdir(struct dentry * d)
260 {
261         remove_dir(d);
262 }
263
264
265 /**
266  *      sysfs_remove_dir - remove an object's directory.
267  *      @kobj:  object. 
268  *
269  *      The only thing special about this is that we remove any files in 
270  *      the directory before we remove the directory, and we've inlined
271  *      what used to be sysfs_rmdir() below, instead of calling separately.
272  */
273
274 void sysfs_remove_dir(struct kobject * kobj)
275 {
276         struct dentry * dentry = dget(kobj->dentry);
277         struct sysfs_dirent * parent_sd;
278         struct sysfs_dirent * sd, * tmp;
279
280         if (!dentry)
281                 return;
282
283         pr_debug("sysfs %s: removing dir\n",dentry->d_name.name);
284         down(&dentry->d_inode->i_sem);
285         parent_sd = dentry->d_fsdata;
286         list_for_each_entry_safe(sd, tmp, &parent_sd->s_children, s_sibling) {
287                 if (!sd->s_element || !(sd->s_type & SYSFS_NOT_PINNED))
288                         continue;
289                 list_del_init(&sd->s_sibling);
290                 sysfs_drop_dentry(sd, dentry);
291                 sysfs_put(sd);
292         }
293         up(&dentry->d_inode->i_sem);
294
295         remove_dir(dentry);
296         /**
297          * Drop reference from dget() on entrance.
298          */
299         dput(dentry);
300 }
301
302 int sysfs_rename_dir(struct kobject * kobj, const char *new_name)
303 {
304         int error = 0;
305         struct dentry * new_dentry, * parent;
306
307         if (!strcmp(kobject_name(kobj), new_name))
308                 return -EINVAL;
309
310         if (!kobj->parent)
311                 return -EINVAL;
312
313         down_write(&sysfs_rename_sem);
314         parent = kobj->parent->dentry;
315
316         down(&parent->d_inode->i_sem);
317
318         new_dentry = sysfs_get_dentry(parent, new_name);
319         if (!IS_ERR(new_dentry)) {
320                 if (!new_dentry->d_inode) {
321                         error = kobject_set_name(kobj, "%s", new_name);
322                         if (!error) {
323                                 d_add(new_dentry, NULL);
324                                 d_move(kobj->dentry, new_dentry);
325                         }
326                         else
327                                 d_drop(new_dentry);
328                 } else
329                         error = -EEXIST;
330                 dput(new_dentry);
331         }
332         up(&parent->d_inode->i_sem);    
333         up_write(&sysfs_rename_sem);
334
335         return error;
336 }
337
338 static int sysfs_dir_open(struct inode *inode, struct file *file)
339 {
340         struct dentry * dentry = file->f_dentry;
341         struct sysfs_dirent * parent_sd = dentry->d_fsdata;
342
343         down(&dentry->d_inode->i_sem);
344         file->private_data = sysfs_new_dirent(parent_sd, NULL);
345         up(&dentry->d_inode->i_sem);
346
347         return file->private_data ? 0 : -ENOMEM;
348
349 }
350
351 static int sysfs_dir_close(struct inode *inode, struct file *file)
352 {
353         struct dentry * dentry = file->f_dentry;
354         struct sysfs_dirent * cursor = file->private_data;
355
356         down(&dentry->d_inode->i_sem);
357         list_del_init(&cursor->s_sibling);
358         up(&dentry->d_inode->i_sem);
359
360         release_sysfs_dirent(cursor);
361
362         return 0;
363 }
364
365 /* Relationship between s_mode and the DT_xxx types */
366 static inline unsigned char dt_type(struct sysfs_dirent *sd)
367 {
368         return (sd->s_mode >> 12) & 15;
369 }
370
371 static int sysfs_readdir(struct file * filp, void * dirent, filldir_t filldir)
372 {
373         struct dentry *dentry = filp->f_dentry;
374         struct sysfs_dirent * parent_sd = dentry->d_fsdata;
375         struct sysfs_dirent *cursor = filp->private_data;
376         struct list_head *p, *q = &cursor->s_sibling;
377         ino_t ino;
378         int i = filp->f_pos;
379
380         switch (i) {
381                 case 0:
382                         ino = dentry->d_inode->i_ino;
383                         if (filldir(dirent, ".", 1, i, ino, DT_DIR) < 0)
384                                 break;
385                         filp->f_pos++;
386                         i++;
387                         /* fallthrough */
388                 case 1:
389                         ino = parent_ino(dentry);
390                         if (filldir(dirent, "..", 2, i, ino, DT_DIR) < 0)
391                                 break;
392                         filp->f_pos++;
393                         i++;
394                         /* fallthrough */
395                 default:
396                         if (filp->f_pos == 2) {
397                                 list_del(q);
398                                 list_add(q, &parent_sd->s_children);
399                         }
400                         for (p=q->next; p!= &parent_sd->s_children; p=p->next) {
401                                 struct sysfs_dirent *next;
402                                 const char * name;
403                                 int len;
404
405                                 next = list_entry(p, struct sysfs_dirent,
406                                                    s_sibling);
407                                 if (!next->s_element)
408                                         continue;
409
410                                 name = sysfs_get_name(next);
411                                 len = strlen(name);
412                                 if (next->s_dentry)
413                                         ino = next->s_dentry->d_inode->i_ino;
414                                 else
415                                         ino = iunique(sysfs_sb, 2);
416
417                                 if (filldir(dirent, name, len, filp->f_pos, ino,
418                                                  dt_type(next)) < 0)
419                                         return 0;
420
421                                 list_del(q);
422                                 list_add(q, p);
423                                 p = q;
424                                 filp->f_pos++;
425                         }
426         }
427         return 0;
428 }
429
430 static loff_t sysfs_dir_lseek(struct file * file, loff_t offset, int origin)
431 {
432         struct dentry * dentry = file->f_dentry;
433
434         down(&dentry->d_inode->i_sem);
435         switch (origin) {
436                 case 1:
437                         offset += file->f_pos;
438                 case 0:
439                         if (offset >= 0)
440                                 break;
441                 default:
442                         up(&file->f_dentry->d_inode->i_sem);
443                         return -EINVAL;
444         }
445         if (offset != file->f_pos) {
446                 file->f_pos = offset;
447                 if (file->f_pos >= 2) {
448                         struct sysfs_dirent *sd = dentry->d_fsdata;
449                         struct sysfs_dirent *cursor = file->private_data;
450                         struct list_head *p;
451                         loff_t n = file->f_pos - 2;
452
453                         list_del(&cursor->s_sibling);
454                         p = sd->s_children.next;
455                         while (n && p != &sd->s_children) {
456                                 struct sysfs_dirent *next;
457                                 next = list_entry(p, struct sysfs_dirent,
458                                                    s_sibling);
459                                 if (next->s_element)
460                                         n--;
461                                 p = p->next;
462                         }
463                         list_add_tail(&cursor->s_sibling, p);
464                 }
465         }
466         up(&dentry->d_inode->i_sem);
467         return offset;
468 }
469
470 struct file_operations sysfs_dir_operations = {
471         .open           = sysfs_dir_open,
472         .release        = sysfs_dir_close,
473         .llseek         = sysfs_dir_lseek,
474         .read           = generic_read_dir,
475         .readdir        = sysfs_readdir,
476 };
477
478 EXPORT_SYMBOL_GPL(sysfs_create_dir);
479 EXPORT_SYMBOL_GPL(sysfs_remove_dir);
480 EXPORT_SYMBOL_GPL(sysfs_rename_dir);
481