59734ba1ee6026556af405cfe77a6bf21f30084e
[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         INIT_LIST_HEAD(&sd->s_children);
47         list_add(&sd->s_sibling, &parent_sd->s_children);
48         sd->s_element = element;
49
50         return sd;
51 }
52
53 int sysfs_make_dirent(struct sysfs_dirent * parent_sd, struct dentry * dentry,
54                         void * element, umode_t mode, int type)
55 {
56         struct sysfs_dirent * sd;
57
58         sd = sysfs_new_dirent(parent_sd, element);
59         if (!sd)
60                 return -ENOMEM;
61
62         sd->s_mode = mode;
63         sd->s_type = type;
64         sd->s_dentry = dentry;
65         if (dentry) {
66                 dentry->d_fsdata = sysfs_get(sd);
67                 dentry->d_op = &sysfs_dentry_ops;
68         }
69
70         return 0;
71 }
72
73 static int init_dir(struct inode * inode)
74 {
75         inode->i_op = &sysfs_dir_inode_operations;
76         inode->i_fop = &sysfs_dir_operations;
77
78         /* directory inodes start off with i_nlink == 2 (for "." entry) */
79         inode->i_nlink++;
80         return 0;
81 }
82
83 static int init_file(struct inode * inode)
84 {
85         inode->i_size = PAGE_SIZE;
86         inode->i_fop = &sysfs_file_operations;
87         return 0;
88 }
89
90 static int init_symlink(struct inode * inode)
91 {
92         inode->i_op = &sysfs_symlink_inode_operations;
93         return 0;
94 }
95
96 static int create_dir(struct kobject * k, struct dentry * p,
97                       const char * n, struct dentry ** d)
98 {
99         int error;
100         umode_t mode = S_IFDIR| S_IRWXU | S_IRUGO | S_IXUGO;
101
102         down(&p->d_inode->i_sem);
103         *d = lookup_one_len(n, p, strlen(n));
104         if (!IS_ERR(*d)) {
105                 error = sysfs_make_dirent(p->d_fsdata, *d, k, mode, SYSFS_DIR);
106                 if (!error) {
107                         error = sysfs_create(*d, mode, init_dir);
108                         if (!error) {
109                                 p->d_inode->i_nlink++;
110                                 (*d)->d_op = &sysfs_dentry_ops;
111                                 d_rehash(*d);
112                         }
113                 }
114                 if (error && (error != -EEXIST)) {
115                         sysfs_put((*d)->d_fsdata);
116                         d_drop(*d);
117                 }
118                 dput(*d);
119         } else
120                 error = PTR_ERR(*d);
121         up(&p->d_inode->i_sem);
122         return error;
123 }
124
125
126 int sysfs_create_subdir(struct kobject * k, const char * n, struct dentry ** d)
127 {
128         return create_dir(k,k->dentry,n,d);
129 }
130
131 /**
132  *      sysfs_create_dir - create a directory for an object.
133  *      @parent:        parent parent object.
134  *      @kobj:          object we're creating directory for. 
135  */
136
137 int sysfs_create_dir(struct kobject * kobj)
138 {
139         struct dentry * dentry = NULL;
140         struct dentry * parent;
141         int error = 0;
142
143         BUG_ON(!kobj);
144
145         if (kobj->parent)
146                 parent = kobj->parent->dentry;
147         else if (sysfs_mount && sysfs_mount->mnt_sb)
148                 parent = sysfs_mount->mnt_sb->s_root;
149         else
150                 return -EFAULT;
151
152         error = create_dir(kobj,parent,kobject_name(kobj),&dentry);
153         if (!error)
154                 kobj->dentry = dentry;
155         return error;
156 }
157
158 /* attaches attribute's sysfs_dirent to the dentry corresponding to the
159  * attribute file
160  */
161 static int sysfs_attach_attr(struct sysfs_dirent * sd, struct dentry * dentry)
162 {
163         struct attribute * attr = NULL;
164         struct bin_attribute * bin_attr = NULL;
165         int (* init) (struct inode *) = NULL;
166         int error = 0;
167
168         if (sd->s_type & SYSFS_KOBJ_BIN_ATTR) {
169                 bin_attr = sd->s_element;
170                 attr = &bin_attr->attr;
171         } else {
172                 attr = sd->s_element;
173                 init = init_file;
174         }
175
176         dentry->d_fsdata = sysfs_get(sd);
177         sd->s_dentry = dentry;
178         error = sysfs_create(dentry, (attr->mode & S_IALLUGO) | S_IFREG, init);
179         if (error) {
180                 sysfs_put(sd);
181                 return error;
182         }
183
184         if (bin_attr) {
185                 dentry->d_inode->i_size = bin_attr->size;
186                 dentry->d_inode->i_fop = &bin_fops;
187         }
188         dentry->d_op = &sysfs_dentry_ops;
189         d_rehash(dentry);
190
191         return 0;
192 }
193
194 static int sysfs_attach_link(struct sysfs_dirent * sd, struct dentry * dentry)
195 {
196         int err = 0;
197
198         dentry->d_fsdata = sysfs_get(sd);
199         sd->s_dentry = dentry;
200         err = sysfs_create(dentry, S_IFLNK|S_IRWXUGO, init_symlink);
201         if (!err) {
202                 dentry->d_op = &sysfs_dentry_ops;
203                 d_rehash(dentry);
204         } else
205                 sysfs_put(sd);
206
207         return err;
208 }
209
210 static struct dentry * sysfs_lookup(struct inode *dir, struct dentry *dentry,
211                                 struct nameidata *nd)
212 {
213         struct sysfs_dirent * parent_sd = dentry->d_parent->d_fsdata;
214         struct sysfs_dirent * sd;
215         int err = 0;
216
217         list_for_each_entry(sd, &parent_sd->s_children, s_sibling) {
218                 if (sd->s_type & SYSFS_NOT_PINNED) {
219                         const unsigned char * name = sysfs_get_name(sd);
220
221                         if (strcmp(name, dentry->d_name.name))
222                                 continue;
223
224                         if (sd->s_type & SYSFS_KOBJ_LINK)
225                                 err = sysfs_attach_link(sd, dentry);
226                         else
227                                 err = sysfs_attach_attr(sd, dentry);
228                         break;
229                 }
230         }
231
232         return ERR_PTR(err);
233 }
234
235 struct inode_operations sysfs_dir_inode_operations = {
236         .lookup         = sysfs_lookup,
237         .setattr        = sysfs_setattr,
238 };
239
240 static void remove_dir(struct dentry * d)
241 {
242         struct dentry * parent = dget(d->d_parent);
243         struct sysfs_dirent * sd;
244
245         down(&parent->d_inode->i_sem);
246         d_delete(d);
247         sd = d->d_fsdata;
248         list_del_init(&sd->s_sibling);
249         sysfs_put(sd);
250         if (d->d_inode)
251                 simple_rmdir(parent->d_inode,d);
252
253         pr_debug(" o %s removing done (%d)\n",d->d_name.name,
254                  atomic_read(&d->d_count));
255
256         up(&parent->d_inode->i_sem);
257         dput(parent);
258 }
259
260 void sysfs_remove_subdir(struct dentry * d)
261 {
262         remove_dir(d);
263 }
264
265
266 /**
267  *      sysfs_remove_dir - remove an object's directory.
268  *      @kobj:  object. 
269  *
270  *      The only thing special about this is that we remove any files in 
271  *      the directory before we remove the directory, and we've inlined
272  *      what used to be sysfs_rmdir() below, instead of calling separately.
273  */
274
275 void sysfs_remove_dir(struct kobject * kobj)
276 {
277         struct dentry * dentry = dget(kobj->dentry);
278         struct sysfs_dirent * parent_sd;
279         struct sysfs_dirent * sd, * tmp;
280
281         if (!dentry)
282                 return;
283
284         pr_debug("sysfs %s: removing dir\n",dentry->d_name.name);
285         down(&dentry->d_inode->i_sem);
286         parent_sd = dentry->d_fsdata;
287         list_for_each_entry_safe(sd, tmp, &parent_sd->s_children, s_sibling) {
288                 if (!sd->s_element || !(sd->s_type & SYSFS_NOT_PINNED))
289                         continue;
290                 list_del_init(&sd->s_sibling);
291                 sysfs_drop_dentry(sd, dentry);
292                 sysfs_put(sd);
293         }
294         up(&dentry->d_inode->i_sem);
295
296         remove_dir(dentry);
297         /**
298          * Drop reference from dget() on entrance.
299          */
300         dput(dentry);
301 }
302
303 int sysfs_rename_dir(struct kobject * kobj, const char *new_name)
304 {
305         int error = 0;
306         struct dentry * new_dentry, * parent;
307
308         if (!strcmp(kobject_name(kobj), new_name))
309                 return -EINVAL;
310
311         if (!kobj->parent)
312                 return -EINVAL;
313
314         down_write(&sysfs_rename_sem);
315         parent = kobj->parent->dentry;
316
317         down(&parent->d_inode->i_sem);
318
319         new_dentry = lookup_one_len(new_name, parent, strlen(new_name));
320         if (!IS_ERR(new_dentry)) {
321                 if (!new_dentry->d_inode) {
322                         error = kobject_set_name(kobj, "%s", new_name);
323                         if (!error) {
324                                 d_add(new_dentry, NULL);
325                                 d_move(kobj->dentry, new_dentry);
326                         }
327                         else
328                                 d_drop(new_dentry);
329                 } else
330                         error = -EEXIST;
331                 dput(new_dentry);
332         }
333         up(&parent->d_inode->i_sem);    
334         up_write(&sysfs_rename_sem);
335
336         return error;
337 }
338
339 static int sysfs_dir_open(struct inode *inode, struct file *file)
340 {
341         struct dentry * dentry = file->f_dentry;
342         struct sysfs_dirent * parent_sd = dentry->d_fsdata;
343
344         down(&dentry->d_inode->i_sem);
345         file->private_data = sysfs_new_dirent(parent_sd, NULL);
346         up(&dentry->d_inode->i_sem);
347
348         return file->private_data ? 0 : -ENOMEM;
349
350 }
351
352 static int sysfs_dir_close(struct inode *inode, struct file *file)
353 {
354         struct dentry * dentry = file->f_dentry;
355         struct sysfs_dirent * cursor = file->private_data;
356
357         down(&dentry->d_inode->i_sem);
358         list_del_init(&cursor->s_sibling);
359         up(&dentry->d_inode->i_sem);
360
361         release_sysfs_dirent(cursor);
362
363         return 0;
364 }
365
366 /* Relationship between s_mode and the DT_xxx types */
367 static inline unsigned char dt_type(struct sysfs_dirent *sd)
368 {
369         return (sd->s_mode >> 12) & 15;
370 }
371
372 static int sysfs_readdir(struct file * filp, void * dirent, filldir_t filldir)
373 {
374         struct dentry *dentry = filp->f_dentry;
375         struct sysfs_dirent * parent_sd = dentry->d_fsdata;
376         struct sysfs_dirent *cursor = filp->private_data;
377         struct list_head *p, *q = &cursor->s_sibling;
378         ino_t ino;
379         int i = filp->f_pos;
380
381         switch (i) {
382                 case 0:
383                         ino = dentry->d_inode->i_ino;
384                         if (filldir(dirent, ".", 1, i, ino, DT_DIR) < 0)
385                                 break;
386                         filp->f_pos++;
387                         i++;
388                         /* fallthrough */
389                 case 1:
390                         ino = parent_ino(dentry);
391                         if (filldir(dirent, "..", 2, i, ino, DT_DIR) < 0)
392                                 break;
393                         filp->f_pos++;
394                         i++;
395                         /* fallthrough */
396                 default:
397                         if (filp->f_pos == 2) {
398                                 list_del(q);
399                                 list_add(q, &parent_sd->s_children);
400                         }
401                         for (p=q->next; p!= &parent_sd->s_children; p=p->next) {
402                                 struct sysfs_dirent *next;
403                                 const char * name;
404                                 int len;
405
406                                 next = list_entry(p, struct sysfs_dirent,
407                                                    s_sibling);
408                                 if (!next->s_element)
409                                         continue;
410
411                                 name = sysfs_get_name(next);
412                                 len = strlen(name);
413                                 if (next->s_dentry)
414                                         ino = next->s_dentry->d_inode->i_ino;
415                                 else
416                                         ino = iunique(sysfs_sb, 2);
417
418                                 if (filldir(dirent, name, len, filp->f_pos, ino,
419                                                  dt_type(next)) < 0)
420                                         return 0;
421
422                                 list_del(q);
423                                 list_add(q, p);
424                                 p = q;
425                                 filp->f_pos++;
426                         }
427         }
428         return 0;
429 }
430
431 static loff_t sysfs_dir_lseek(struct file * file, loff_t offset, int origin)
432 {
433         struct dentry * dentry = file->f_dentry;
434
435         down(&dentry->d_inode->i_sem);
436         switch (origin) {
437                 case 1:
438                         offset += file->f_pos;
439                 case 0:
440                         if (offset >= 0)
441                                 break;
442                 default:
443                         up(&file->f_dentry->d_inode->i_sem);
444                         return -EINVAL;
445         }
446         if (offset != file->f_pos) {
447                 file->f_pos = offset;
448                 if (file->f_pos >= 2) {
449                         struct sysfs_dirent *sd = dentry->d_fsdata;
450                         struct sysfs_dirent *cursor = file->private_data;
451                         struct list_head *p;
452                         loff_t n = file->f_pos - 2;
453
454                         list_del(&cursor->s_sibling);
455                         p = sd->s_children.next;
456                         while (n && p != &sd->s_children) {
457                                 struct sysfs_dirent *next;
458                                 next = list_entry(p, struct sysfs_dirent,
459                                                    s_sibling);
460                                 if (next->s_element)
461                                         n--;
462                                 p = p->next;
463                         }
464                         list_add_tail(&cursor->s_sibling, p);
465                 }
466         }
467         up(&dentry->d_inode->i_sem);
468         return offset;
469 }
470
471 struct file_operations sysfs_dir_operations = {
472         .open           = sysfs_dir_open,
473         .release        = sysfs_dir_close,
474         .llseek         = sysfs_dir_lseek,
475         .read           = generic_read_dir,
476         .readdir        = sysfs_readdir,
477 };
478
479 EXPORT_SYMBOL_GPL(sysfs_create_dir);
480 EXPORT_SYMBOL_GPL(sysfs_remove_dir);
481 EXPORT_SYMBOL_GPL(sysfs_rename_dir);
482