[PATCH] sysctl: C99 convert arch/mips/lasat/sysctl.c and remove ABI breakage
[linux-2.6/kmemtrace.git] / fs / sysfs / dir.c
blob8813990304fe58f8b12449b6f99471887f1920ee
1 /*
2 * dir.c - Operations for sysfs directories.
3 */
5 #undef DEBUG
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 <asm/semaphore.h>
13 #include "sysfs.h"
15 DECLARE_RWSEM(sysfs_rename_sem);
17 static void sysfs_d_iput(struct dentry * dentry, struct inode * inode)
19 struct sysfs_dirent * sd = dentry->d_fsdata;
21 if (sd) {
22 BUG_ON(sd->s_dentry != dentry);
23 sd->s_dentry = NULL;
24 sysfs_put(sd);
26 iput(inode);
29 static struct dentry_operations sysfs_dentry_ops = {
30 .d_iput = sysfs_d_iput,
34 * Allocates a new sysfs_dirent and links it to the parent sysfs_dirent
36 static struct sysfs_dirent * __sysfs_new_dirent(void * element)
38 struct sysfs_dirent * sd;
40 sd = kmem_cache_zalloc(sysfs_dir_cachep, GFP_KERNEL);
41 if (!sd)
42 return NULL;
44 atomic_set(&sd->s_count, 1);
45 atomic_set(&sd->s_event, 1);
46 INIT_LIST_HEAD(&sd->s_children);
47 INIT_LIST_HEAD(&sd->s_sibling);
48 sd->s_element = element;
50 return sd;
53 static void __sysfs_list_dirent(struct sysfs_dirent *parent_sd,
54 struct sysfs_dirent *sd)
56 if (sd)
57 list_add(&sd->s_sibling, &parent_sd->s_children);
60 static struct sysfs_dirent * sysfs_new_dirent(struct sysfs_dirent *parent_sd,
61 void * element)
63 struct sysfs_dirent *sd;
64 sd = __sysfs_new_dirent(element);
65 __sysfs_list_dirent(parent_sd, sd);
66 return sd;
71 * Return -EEXIST if there is already a sysfs element with the same name for
72 * the same parent.
74 * called with parent inode's i_mutex held
76 int sysfs_dirent_exist(struct sysfs_dirent *parent_sd,
77 const unsigned char *new)
79 struct sysfs_dirent * sd;
81 list_for_each_entry(sd, &parent_sd->s_children, s_sibling) {
82 if (sd->s_element) {
83 const unsigned char *existing = sysfs_get_name(sd);
84 if (strcmp(existing, new))
85 continue;
86 else
87 return -EEXIST;
91 return 0;
95 static struct sysfs_dirent *
96 __sysfs_make_dirent(struct dentry *dentry, void *element, mode_t mode, int type)
98 struct sysfs_dirent * sd;
100 sd = __sysfs_new_dirent(element);
101 if (!sd)
102 goto out;
104 sd->s_mode = mode;
105 sd->s_type = type;
106 sd->s_dentry = dentry;
107 if (dentry) {
108 dentry->d_fsdata = sysfs_get(sd);
109 dentry->d_op = &sysfs_dentry_ops;
112 out:
113 return sd;
116 int sysfs_make_dirent(struct sysfs_dirent * parent_sd, struct dentry * dentry,
117 void * element, umode_t mode, int type)
119 struct sysfs_dirent *sd;
121 sd = __sysfs_make_dirent(dentry, element, mode, type);
122 __sysfs_list_dirent(parent_sd, sd);
124 return sd ? 0 : -ENOMEM;
127 static int init_dir(struct inode * inode)
129 inode->i_op = &sysfs_dir_inode_operations;
130 inode->i_fop = &sysfs_dir_operations;
132 /* directory inodes start off with i_nlink == 2 (for "." entry) */
133 inc_nlink(inode);
134 return 0;
137 static int init_file(struct inode * inode)
139 inode->i_size = PAGE_SIZE;
140 inode->i_fop = &sysfs_file_operations;
141 return 0;
144 static int init_symlink(struct inode * inode)
146 inode->i_op = &sysfs_symlink_inode_operations;
147 return 0;
150 static int create_dir(struct kobject * k, struct dentry * p,
151 const char * n, struct dentry ** d)
153 int error;
154 umode_t mode = S_IFDIR| S_IRWXU | S_IRUGO | S_IXUGO;
156 mutex_lock(&p->d_inode->i_mutex);
157 *d = lookup_one_len(n, p, strlen(n));
158 if (!IS_ERR(*d)) {
159 if (sysfs_dirent_exist(p->d_fsdata, n))
160 error = -EEXIST;
161 else
162 error = sysfs_make_dirent(p->d_fsdata, *d, k, mode,
163 SYSFS_DIR);
164 if (!error) {
165 error = sysfs_create(*d, mode, init_dir);
166 if (!error) {
167 inc_nlink(p->d_inode);
168 (*d)->d_op = &sysfs_dentry_ops;
169 d_rehash(*d);
172 if (error && (error != -EEXIST)) {
173 struct sysfs_dirent *sd = (*d)->d_fsdata;
174 if (sd) {
175 list_del_init(&sd->s_sibling);
176 sysfs_put(sd);
178 d_drop(*d);
180 dput(*d);
181 } else
182 error = PTR_ERR(*d);
183 mutex_unlock(&p->d_inode->i_mutex);
184 return error;
188 int sysfs_create_subdir(struct kobject * k, const char * n, struct dentry ** d)
190 return create_dir(k,k->dentry,n,d);
194 * sysfs_create_dir - create a directory for an object.
195 * @kobj: object we're creating directory for.
196 * @shadow_parent: parent parent object.
199 int sysfs_create_dir(struct kobject * kobj, struct dentry *shadow_parent)
201 struct dentry * dentry = NULL;
202 struct dentry * parent;
203 int error = 0;
205 BUG_ON(!kobj);
207 if (shadow_parent)
208 parent = shadow_parent;
209 else if (kobj->parent)
210 parent = kobj->parent->dentry;
211 else if (sysfs_mount && sysfs_mount->mnt_sb)
212 parent = sysfs_mount->mnt_sb->s_root;
213 else
214 return -EFAULT;
216 error = create_dir(kobj,parent,kobject_name(kobj),&dentry);
217 if (!error)
218 kobj->dentry = dentry;
219 return error;
222 /* attaches attribute's sysfs_dirent to the dentry corresponding to the
223 * attribute file
225 static int sysfs_attach_attr(struct sysfs_dirent * sd, struct dentry * dentry)
227 struct attribute * attr = NULL;
228 struct bin_attribute * bin_attr = NULL;
229 int (* init) (struct inode *) = NULL;
230 int error = 0;
232 if (sd->s_type & SYSFS_KOBJ_BIN_ATTR) {
233 bin_attr = sd->s_element;
234 attr = &bin_attr->attr;
235 } else {
236 attr = sd->s_element;
237 init = init_file;
240 dentry->d_fsdata = sysfs_get(sd);
241 sd->s_dentry = dentry;
242 error = sysfs_create(dentry, (attr->mode & S_IALLUGO) | S_IFREG, init);
243 if (error) {
244 sysfs_put(sd);
245 return error;
248 if (bin_attr) {
249 dentry->d_inode->i_size = bin_attr->size;
250 dentry->d_inode->i_fop = &bin_fops;
252 dentry->d_op = &sysfs_dentry_ops;
253 d_rehash(dentry);
255 return 0;
258 static int sysfs_attach_link(struct sysfs_dirent * sd, struct dentry * dentry)
260 int err = 0;
262 dentry->d_fsdata = sysfs_get(sd);
263 sd->s_dentry = dentry;
264 err = sysfs_create(dentry, S_IFLNK|S_IRWXUGO, init_symlink);
265 if (!err) {
266 dentry->d_op = &sysfs_dentry_ops;
267 d_rehash(dentry);
268 } else
269 sysfs_put(sd);
271 return err;
274 static struct dentry * sysfs_lookup(struct inode *dir, struct dentry *dentry,
275 struct nameidata *nd)
277 struct sysfs_dirent * parent_sd = dentry->d_parent->d_fsdata;
278 struct sysfs_dirent * sd;
279 int err = 0;
281 list_for_each_entry(sd, &parent_sd->s_children, s_sibling) {
282 if (sd->s_type & SYSFS_NOT_PINNED) {
283 const unsigned char * name = sysfs_get_name(sd);
285 if (strcmp(name, dentry->d_name.name))
286 continue;
288 if (sd->s_type & SYSFS_KOBJ_LINK)
289 err = sysfs_attach_link(sd, dentry);
290 else
291 err = sysfs_attach_attr(sd, dentry);
292 break;
296 return ERR_PTR(err);
299 const struct inode_operations sysfs_dir_inode_operations = {
300 .lookup = sysfs_lookup,
301 .setattr = sysfs_setattr,
304 static void remove_dir(struct dentry * d)
306 struct dentry * parent = dget(d->d_parent);
307 struct sysfs_dirent * sd;
309 mutex_lock(&parent->d_inode->i_mutex);
310 d_delete(d);
311 sd = d->d_fsdata;
312 list_del_init(&sd->s_sibling);
313 sysfs_put(sd);
314 if (d->d_inode)
315 simple_rmdir(parent->d_inode,d);
317 pr_debug(" o %s removing done (%d)\n",d->d_name.name,
318 atomic_read(&d->d_count));
320 mutex_unlock(&parent->d_inode->i_mutex);
321 dput(parent);
324 void sysfs_remove_subdir(struct dentry * d)
326 remove_dir(d);
330 static void __sysfs_remove_dir(struct dentry *dentry)
332 struct sysfs_dirent * parent_sd;
333 struct sysfs_dirent * sd, * tmp;
335 dget(dentry);
336 if (!dentry)
337 return;
339 pr_debug("sysfs %s: removing dir\n",dentry->d_name.name);
340 mutex_lock(&dentry->d_inode->i_mutex);
341 parent_sd = dentry->d_fsdata;
342 list_for_each_entry_safe(sd, tmp, &parent_sd->s_children, s_sibling) {
343 if (!sd->s_element || !(sd->s_type & SYSFS_NOT_PINNED))
344 continue;
345 list_del_init(&sd->s_sibling);
346 sysfs_drop_dentry(sd, dentry);
347 sysfs_put(sd);
349 mutex_unlock(&dentry->d_inode->i_mutex);
351 remove_dir(dentry);
353 * Drop reference from dget() on entrance.
355 dput(dentry);
359 * sysfs_remove_dir - remove an object's directory.
360 * @kobj: object.
362 * The only thing special about this is that we remove any files in
363 * the directory before we remove the directory, and we've inlined
364 * what used to be sysfs_rmdir() below, instead of calling separately.
367 void sysfs_remove_dir(struct kobject * kobj)
369 __sysfs_remove_dir(kobj->dentry);
370 kobj->dentry = NULL;
373 int sysfs_rename_dir(struct kobject * kobj, struct dentry *new_parent,
374 const char *new_name)
376 int error = 0;
377 struct dentry * new_dentry;
379 if (!new_parent)
380 return -EFAULT;
382 down_write(&sysfs_rename_sem);
383 mutex_lock(&new_parent->d_inode->i_mutex);
385 new_dentry = lookup_one_len(new_name, new_parent, strlen(new_name));
386 if (!IS_ERR(new_dentry)) {
387 /* By allowing two different directories with the
388 * same d_parent we allow this routine to move
389 * between different shadows of the same directory
391 if (kobj->dentry->d_parent->d_inode != new_parent->d_inode)
392 return -EINVAL;
393 else if (new_dentry->d_parent->d_inode != new_parent->d_inode)
394 error = -EINVAL;
395 else if (new_dentry == kobj->dentry)
396 error = -EINVAL;
397 else if (!new_dentry->d_inode) {
398 error = kobject_set_name(kobj, "%s", new_name);
399 if (!error) {
400 struct sysfs_dirent *sd, *parent_sd;
402 d_add(new_dentry, NULL);
403 d_move(kobj->dentry, new_dentry);
405 sd = kobj->dentry->d_fsdata;
406 parent_sd = new_parent->d_fsdata;
408 list_del_init(&sd->s_sibling);
409 list_add(&sd->s_sibling, &parent_sd->s_children);
411 else
412 d_drop(new_dentry);
413 } else
414 error = -EEXIST;
415 dput(new_dentry);
417 mutex_unlock(&new_parent->d_inode->i_mutex);
418 up_write(&sysfs_rename_sem);
420 return error;
423 int sysfs_move_dir(struct kobject *kobj, struct kobject *new_parent)
425 struct dentry *old_parent_dentry, *new_parent_dentry, *new_dentry;
426 struct sysfs_dirent *new_parent_sd, *sd;
427 int error;
429 old_parent_dentry = kobj->parent ?
430 kobj->parent->dentry : sysfs_mount->mnt_sb->s_root;
431 new_parent_dentry = new_parent ?
432 new_parent->dentry : sysfs_mount->mnt_sb->s_root;
434 again:
435 mutex_lock(&old_parent_dentry->d_inode->i_mutex);
436 if (!mutex_trylock(&new_parent_dentry->d_inode->i_mutex)) {
437 mutex_unlock(&old_parent_dentry->d_inode->i_mutex);
438 goto again;
441 new_parent_sd = new_parent_dentry->d_fsdata;
442 sd = kobj->dentry->d_fsdata;
444 new_dentry = lookup_one_len(kobj->name, new_parent_dentry,
445 strlen(kobj->name));
446 if (IS_ERR(new_dentry)) {
447 error = PTR_ERR(new_dentry);
448 goto out;
449 } else
450 error = 0;
451 d_add(new_dentry, NULL);
452 d_move(kobj->dentry, new_dentry);
453 dput(new_dentry);
455 /* Remove from old parent's list and insert into new parent's list. */
456 list_del_init(&sd->s_sibling);
457 list_add(&sd->s_sibling, &new_parent_sd->s_children);
459 out:
460 mutex_unlock(&new_parent_dentry->d_inode->i_mutex);
461 mutex_unlock(&old_parent_dentry->d_inode->i_mutex);
463 return error;
466 static int sysfs_dir_open(struct inode *inode, struct file *file)
468 struct dentry * dentry = file->f_path.dentry;
469 struct sysfs_dirent * parent_sd = dentry->d_fsdata;
471 mutex_lock(&dentry->d_inode->i_mutex);
472 file->private_data = sysfs_new_dirent(parent_sd, NULL);
473 mutex_unlock(&dentry->d_inode->i_mutex);
475 return file->private_data ? 0 : -ENOMEM;
479 static int sysfs_dir_close(struct inode *inode, struct file *file)
481 struct dentry * dentry = file->f_path.dentry;
482 struct sysfs_dirent * cursor = file->private_data;
484 mutex_lock(&dentry->d_inode->i_mutex);
485 list_del_init(&cursor->s_sibling);
486 mutex_unlock(&dentry->d_inode->i_mutex);
488 release_sysfs_dirent(cursor);
490 return 0;
493 /* Relationship between s_mode and the DT_xxx types */
494 static inline unsigned char dt_type(struct sysfs_dirent *sd)
496 return (sd->s_mode >> 12) & 15;
499 static int sysfs_readdir(struct file * filp, void * dirent, filldir_t filldir)
501 struct dentry *dentry = filp->f_path.dentry;
502 struct sysfs_dirent * parent_sd = dentry->d_fsdata;
503 struct sysfs_dirent *cursor = filp->private_data;
504 struct list_head *p, *q = &cursor->s_sibling;
505 ino_t ino;
506 int i = filp->f_pos;
508 switch (i) {
509 case 0:
510 ino = dentry->d_inode->i_ino;
511 if (filldir(dirent, ".", 1, i, ino, DT_DIR) < 0)
512 break;
513 filp->f_pos++;
514 i++;
515 /* fallthrough */
516 case 1:
517 ino = parent_ino(dentry);
518 if (filldir(dirent, "..", 2, i, ino, DT_DIR) < 0)
519 break;
520 filp->f_pos++;
521 i++;
522 /* fallthrough */
523 default:
524 if (filp->f_pos == 2)
525 list_move(q, &parent_sd->s_children);
527 for (p=q->next; p!= &parent_sd->s_children; p=p->next) {
528 struct sysfs_dirent *next;
529 const char * name;
530 int len;
532 next = list_entry(p, struct sysfs_dirent,
533 s_sibling);
534 if (!next->s_element)
535 continue;
537 name = sysfs_get_name(next);
538 len = strlen(name);
539 if (next->s_dentry)
540 ino = next->s_dentry->d_inode->i_ino;
541 else
542 ino = iunique(sysfs_sb, 2);
544 if (filldir(dirent, name, len, filp->f_pos, ino,
545 dt_type(next)) < 0)
546 return 0;
548 list_move(q, p);
549 p = q;
550 filp->f_pos++;
553 return 0;
556 static loff_t sysfs_dir_lseek(struct file * file, loff_t offset, int origin)
558 struct dentry * dentry = file->f_path.dentry;
560 mutex_lock(&dentry->d_inode->i_mutex);
561 switch (origin) {
562 case 1:
563 offset += file->f_pos;
564 case 0:
565 if (offset >= 0)
566 break;
567 default:
568 mutex_unlock(&file->f_path.dentry->d_inode->i_mutex);
569 return -EINVAL;
571 if (offset != file->f_pos) {
572 file->f_pos = offset;
573 if (file->f_pos >= 2) {
574 struct sysfs_dirent *sd = dentry->d_fsdata;
575 struct sysfs_dirent *cursor = file->private_data;
576 struct list_head *p;
577 loff_t n = file->f_pos - 2;
579 list_del(&cursor->s_sibling);
580 p = sd->s_children.next;
581 while (n && p != &sd->s_children) {
582 struct sysfs_dirent *next;
583 next = list_entry(p, struct sysfs_dirent,
584 s_sibling);
585 if (next->s_element)
586 n--;
587 p = p->next;
589 list_add_tail(&cursor->s_sibling, p);
592 mutex_unlock(&dentry->d_inode->i_mutex);
593 return offset;
598 * sysfs_make_shadowed_dir - Setup so a directory can be shadowed
599 * @kobj: object we're creating shadow of.
602 int sysfs_make_shadowed_dir(struct kobject *kobj,
603 void * (*follow_link)(struct dentry *, struct nameidata *))
605 struct inode *inode;
606 struct inode_operations *i_op;
608 inode = kobj->dentry->d_inode;
609 if (inode->i_op != &sysfs_dir_inode_operations)
610 return -EINVAL;
612 i_op = kmalloc(sizeof(*i_op), GFP_KERNEL);
613 if (!i_op)
614 return -ENOMEM;
616 memcpy(i_op, &sysfs_dir_inode_operations, sizeof(*i_op));
617 i_op->follow_link = follow_link;
619 /* Locking of inode->i_op?
620 * Since setting i_op is a single word write and they
621 * are atomic we should be ok here.
623 inode->i_op = i_op;
624 return 0;
628 * sysfs_create_shadow_dir - create a shadow directory for an object.
629 * @kobj: object we're creating directory for.
631 * sysfs_make_shadowed_dir must already have been called on this
632 * directory.
635 struct dentry *sysfs_create_shadow_dir(struct kobject *kobj)
637 struct sysfs_dirent *sd;
638 struct dentry *parent, *dir, *shadow;
639 struct inode *inode;
641 dir = kobj->dentry;
642 inode = dir->d_inode;
643 parent = dir->d_parent;
644 shadow = ERR_PTR(-EINVAL);
645 if (!sysfs_is_shadowed_inode(inode))
646 goto out;
648 shadow = d_alloc(parent, &dir->d_name);
649 if (!shadow)
650 goto nomem;
652 sd = __sysfs_make_dirent(shadow, kobj, inode->i_mode, SYSFS_DIR);
653 if (!sd)
654 goto nomem;
656 d_instantiate(shadow, igrab(inode));
657 inc_nlink(inode);
658 inc_nlink(parent->d_inode);
659 shadow->d_op = &sysfs_dentry_ops;
661 dget(shadow); /* Extra count - pin the dentry in core */
663 out:
664 return shadow;
665 nomem:
666 dput(shadow);
667 shadow = ERR_PTR(-ENOMEM);
668 goto out;
672 * sysfs_remove_shadow_dir - remove an object's directory.
673 * @shadow: dentry of shadow directory
675 * The only thing special about this is that we remove any files in
676 * the directory before we remove the directory, and we've inlined
677 * what used to be sysfs_rmdir() below, instead of calling separately.
680 void sysfs_remove_shadow_dir(struct dentry *shadow)
682 __sysfs_remove_dir(shadow);
685 const struct file_operations sysfs_dir_operations = {
686 .open = sysfs_dir_open,
687 .release = sysfs_dir_close,
688 .llseek = sysfs_dir_lseek,
689 .read = generic_read_dir,
690 .readdir = sysfs_readdir,