2 * dir.c - Operations for sysfs directories.
8 #include <linux/mount.h>
9 #include <linux/module.h>
10 #include <linux/kobject.h>
11 #include <linux/namei.h>
12 #include <linux/idr.h>
13 #include <asm/semaphore.h>
16 DECLARE_RWSEM(sysfs_rename_sem);
17 spinlock_t sysfs_lock = SPIN_LOCK_UNLOCKED;
19 static spinlock_t sysfs_ino_lock = SPIN_LOCK_UNLOCKED;
20 static DEFINE_IDA(sysfs_ino_ida);
22 int sysfs_alloc_ino(ino_t *pino)
27 spin_lock(&sysfs_ino_lock);
28 rc = ida_get_new_above(&sysfs_ino_ida, 2, &ino);
29 spin_unlock(&sysfs_ino_lock);
32 if (ida_pre_get(&sysfs_ino_ida, GFP_KERNEL))
41 static void sysfs_free_ino(ino_t ino)
43 spin_lock(&sysfs_ino_lock);
44 ida_remove(&sysfs_ino_ida, ino);
45 spin_unlock(&sysfs_ino_lock);
48 void release_sysfs_dirent(struct sysfs_dirent * sd)
50 if (sd->s_type & SYSFS_KOBJ_LINK) {
51 struct sysfs_symlink * sl = sd->s_element;
53 kobject_put(sl->target_kobj);
57 sysfs_free_ino(sd->s_ino);
58 kmem_cache_free(sysfs_dir_cachep, sd);
61 static void sysfs_d_iput(struct dentry * dentry, struct inode * inode)
63 struct sysfs_dirent * sd = dentry->d_fsdata;
66 /* sd->s_dentry is protected with sysfs_lock. This
67 * allows sysfs_drop_dentry() to dereference it.
69 spin_lock(&sysfs_lock);
71 /* The dentry might have been deleted or another
72 * lookup could have happened updating sd->s_dentry to
73 * point the new dentry. Ignore if it isn't pointing
76 if (sd->s_dentry == dentry)
78 spin_unlock(&sysfs_lock);
84 static struct dentry_operations sysfs_dentry_ops = {
85 .d_iput = sysfs_d_iput,
89 * Allocates a new sysfs_dirent and links it to the parent sysfs_dirent
91 static struct sysfs_dirent * __sysfs_new_dirent(void * element)
93 struct sysfs_dirent * sd;
95 sd = kmem_cache_zalloc(sysfs_dir_cachep, GFP_KERNEL);
99 if (sysfs_alloc_ino(&sd->s_ino)) {
100 kmem_cache_free(sysfs_dir_cachep, sd);
104 atomic_set(&sd->s_count, 1);
105 atomic_set(&sd->s_event, 1);
106 INIT_LIST_HEAD(&sd->s_children);
107 INIT_LIST_HEAD(&sd->s_sibling);
108 sd->s_element = element;
113 static void __sysfs_list_dirent(struct sysfs_dirent *parent_sd,
114 struct sysfs_dirent *sd)
117 list_add(&sd->s_sibling, &parent_sd->s_children);
120 static struct sysfs_dirent * sysfs_new_dirent(struct sysfs_dirent *parent_sd,
123 struct sysfs_dirent *sd;
124 sd = __sysfs_new_dirent(element);
125 __sysfs_list_dirent(parent_sd, sd);
131 * Return -EEXIST if there is already a sysfs element with the same name for
134 * called with parent inode's i_mutex held
136 int sysfs_dirent_exist(struct sysfs_dirent *parent_sd,
137 const unsigned char *new)
139 struct sysfs_dirent * sd;
141 list_for_each_entry(sd, &parent_sd->s_children, s_sibling) {
143 const unsigned char *existing = sysfs_get_name(sd);
144 if (strcmp(existing, new))
155 static struct sysfs_dirent *
156 __sysfs_make_dirent(struct dentry *dentry, void *element, mode_t mode, int type)
158 struct sysfs_dirent * sd;
160 sd = __sysfs_new_dirent(element);
166 sd->s_dentry = dentry;
168 dentry->d_fsdata = sysfs_get(sd);
169 dentry->d_op = &sysfs_dentry_ops;
176 int sysfs_make_dirent(struct sysfs_dirent * parent_sd, struct dentry * dentry,
177 void * element, umode_t mode, int type)
179 struct sysfs_dirent *sd;
181 sd = __sysfs_make_dirent(dentry, element, mode, type);
182 __sysfs_list_dirent(parent_sd, sd);
184 return sd ? 0 : -ENOMEM;
187 static int init_dir(struct inode * inode)
189 inode->i_op = &sysfs_dir_inode_operations;
190 inode->i_fop = &sysfs_dir_operations;
192 /* directory inodes start off with i_nlink == 2 (for "." entry) */
197 static int init_file(struct inode * inode)
199 inode->i_size = PAGE_SIZE;
200 inode->i_fop = &sysfs_file_operations;
204 static int init_symlink(struct inode * inode)
206 inode->i_op = &sysfs_symlink_inode_operations;
210 static int create_dir(struct kobject * k, struct dentry * p,
211 const char * n, struct dentry ** d)
214 umode_t mode = S_IFDIR| S_IRWXU | S_IRUGO | S_IXUGO;
216 mutex_lock(&p->d_inode->i_mutex);
217 *d = lookup_one_len(n, p, strlen(n));
219 if (sysfs_dirent_exist(p->d_fsdata, n))
222 error = sysfs_make_dirent(p->d_fsdata, *d, k, mode,
225 error = sysfs_create(*d, mode, init_dir);
227 inc_nlink(p->d_inode);
228 (*d)->d_op = &sysfs_dentry_ops;
232 if (error && (error != -EEXIST)) {
233 struct sysfs_dirent *sd = (*d)->d_fsdata;
235 list_del_init(&sd->s_sibling);
243 mutex_unlock(&p->d_inode->i_mutex);
248 int sysfs_create_subdir(struct kobject * k, const char * n, struct dentry ** d)
250 return create_dir(k,k->dentry,n,d);
254 * sysfs_create_dir - create a directory for an object.
255 * @kobj: object we're creating directory for.
256 * @shadow_parent: parent parent object.
259 int sysfs_create_dir(struct kobject * kobj, struct dentry *shadow_parent)
261 struct dentry * dentry = NULL;
262 struct dentry * parent;
268 parent = shadow_parent;
269 else if (kobj->parent)
270 parent = kobj->parent->dentry;
271 else if (sysfs_mount && sysfs_mount->mnt_sb)
272 parent = sysfs_mount->mnt_sb->s_root;
276 error = create_dir(kobj,parent,kobject_name(kobj),&dentry);
278 kobj->dentry = dentry;
282 /* attaches attribute's sysfs_dirent to the dentry corresponding to the
285 static int sysfs_attach_attr(struct sysfs_dirent * sd, struct dentry * dentry)
287 struct attribute * attr = NULL;
288 struct bin_attribute * bin_attr = NULL;
289 int (* init) (struct inode *) = NULL;
292 if (sd->s_type & SYSFS_KOBJ_BIN_ATTR) {
293 bin_attr = sd->s_element;
294 attr = &bin_attr->attr;
296 attr = sd->s_element;
300 dentry->d_fsdata = sysfs_get(sd);
301 /* protect sd->s_dentry against sysfs_d_iput */
302 spin_lock(&sysfs_lock);
303 sd->s_dentry = dentry;
304 spin_unlock(&sysfs_lock);
305 error = sysfs_create(dentry, (attr->mode & S_IALLUGO) | S_IFREG, init);
312 dentry->d_inode->i_size = bin_attr->size;
313 dentry->d_inode->i_fop = &bin_fops;
315 dentry->d_op = &sysfs_dentry_ops;
321 static int sysfs_attach_link(struct sysfs_dirent * sd, struct dentry * dentry)
325 dentry->d_fsdata = sysfs_get(sd);
326 /* protect sd->s_dentry against sysfs_d_iput */
327 spin_lock(&sysfs_lock);
328 sd->s_dentry = dentry;
329 spin_unlock(&sysfs_lock);
330 err = sysfs_create(dentry, S_IFLNK|S_IRWXUGO, init_symlink);
332 dentry->d_op = &sysfs_dentry_ops;
340 static struct dentry * sysfs_lookup(struct inode *dir, struct dentry *dentry,
341 struct nameidata *nd)
343 struct sysfs_dirent * parent_sd = dentry->d_parent->d_fsdata;
344 struct sysfs_dirent * sd;
347 list_for_each_entry(sd, &parent_sd->s_children, s_sibling) {
348 if (sd->s_type & SYSFS_NOT_PINNED) {
349 const unsigned char * name = sysfs_get_name(sd);
351 if (strcmp(name, dentry->d_name.name))
354 if (sd->s_type & SYSFS_KOBJ_LINK)
355 err = sysfs_attach_link(sd, dentry);
357 err = sysfs_attach_attr(sd, dentry);
365 const struct inode_operations sysfs_dir_inode_operations = {
366 .lookup = sysfs_lookup,
367 .setattr = sysfs_setattr,
370 static void remove_dir(struct dentry * d)
372 struct dentry * parent = dget(d->d_parent);
373 struct sysfs_dirent * sd;
375 mutex_lock(&parent->d_inode->i_mutex);
378 list_del_init(&sd->s_sibling);
381 simple_rmdir(parent->d_inode,d);
383 pr_debug(" o %s removing done (%d)\n",d->d_name.name,
384 atomic_read(&d->d_count));
386 mutex_unlock(&parent->d_inode->i_mutex);
390 void sysfs_remove_subdir(struct dentry * d)
396 static void __sysfs_remove_dir(struct dentry *dentry)
398 struct sysfs_dirent * parent_sd;
399 struct sysfs_dirent * sd, * tmp;
405 pr_debug("sysfs %s: removing dir\n",dentry->d_name.name);
406 mutex_lock(&dentry->d_inode->i_mutex);
407 parent_sd = dentry->d_fsdata;
408 list_for_each_entry_safe(sd, tmp, &parent_sd->s_children, s_sibling) {
409 if (!sd->s_element || !(sd->s_type & SYSFS_NOT_PINNED))
411 list_del_init(&sd->s_sibling);
412 sysfs_drop_dentry(sd, dentry);
415 mutex_unlock(&dentry->d_inode->i_mutex);
419 * Drop reference from dget() on entrance.
425 * sysfs_remove_dir - remove an object's directory.
428 * The only thing special about this is that we remove any files in
429 * the directory before we remove the directory, and we've inlined
430 * what used to be sysfs_rmdir() below, instead of calling separately.
433 void sysfs_remove_dir(struct kobject * kobj)
435 __sysfs_remove_dir(kobj->dentry);
439 int sysfs_rename_dir(struct kobject * kobj, struct dentry *new_parent,
440 const char *new_name)
443 struct dentry * new_dentry;
448 down_write(&sysfs_rename_sem);
449 mutex_lock(&new_parent->d_inode->i_mutex);
451 new_dentry = lookup_one_len(new_name, new_parent, strlen(new_name));
452 if (!IS_ERR(new_dentry)) {
453 /* By allowing two different directories with the
454 * same d_parent we allow this routine to move
455 * between different shadows of the same directory
457 if (kobj->dentry->d_parent->d_inode != new_parent->d_inode)
459 else if (new_dentry->d_parent->d_inode != new_parent->d_inode)
461 else if (new_dentry == kobj->dentry)
463 else if (!new_dentry->d_inode) {
464 error = kobject_set_name(kobj, "%s", new_name);
466 struct sysfs_dirent *sd, *parent_sd;
468 d_add(new_dentry, NULL);
469 d_move(kobj->dentry, new_dentry);
471 sd = kobj->dentry->d_fsdata;
472 parent_sd = new_parent->d_fsdata;
474 list_del_init(&sd->s_sibling);
475 list_add(&sd->s_sibling, &parent_sd->s_children);
483 mutex_unlock(&new_parent->d_inode->i_mutex);
484 up_write(&sysfs_rename_sem);
489 int sysfs_move_dir(struct kobject *kobj, struct kobject *new_parent)
491 struct dentry *old_parent_dentry, *new_parent_dentry, *new_dentry;
492 struct sysfs_dirent *new_parent_sd, *sd;
495 old_parent_dentry = kobj->parent ?
496 kobj->parent->dentry : sysfs_mount->mnt_sb->s_root;
497 new_parent_dentry = new_parent ?
498 new_parent->dentry : sysfs_mount->mnt_sb->s_root;
500 if (old_parent_dentry->d_inode == new_parent_dentry->d_inode)
501 return 0; /* nothing to move */
503 mutex_lock(&old_parent_dentry->d_inode->i_mutex);
504 if (!mutex_trylock(&new_parent_dentry->d_inode->i_mutex)) {
505 mutex_unlock(&old_parent_dentry->d_inode->i_mutex);
509 new_parent_sd = new_parent_dentry->d_fsdata;
510 sd = kobj->dentry->d_fsdata;
512 new_dentry = lookup_one_len(kobj->name, new_parent_dentry,
514 if (IS_ERR(new_dentry)) {
515 error = PTR_ERR(new_dentry);
519 d_add(new_dentry, NULL);
520 d_move(kobj->dentry, new_dentry);
523 /* Remove from old parent's list and insert into new parent's list. */
524 list_del_init(&sd->s_sibling);
525 list_add(&sd->s_sibling, &new_parent_sd->s_children);
528 mutex_unlock(&new_parent_dentry->d_inode->i_mutex);
529 mutex_unlock(&old_parent_dentry->d_inode->i_mutex);
534 static int sysfs_dir_open(struct inode *inode, struct file *file)
536 struct dentry * dentry = file->f_path.dentry;
537 struct sysfs_dirent * parent_sd = dentry->d_fsdata;
539 mutex_lock(&dentry->d_inode->i_mutex);
540 file->private_data = sysfs_new_dirent(parent_sd, NULL);
541 mutex_unlock(&dentry->d_inode->i_mutex);
543 return file->private_data ? 0 : -ENOMEM;
547 static int sysfs_dir_close(struct inode *inode, struct file *file)
549 struct dentry * dentry = file->f_path.dentry;
550 struct sysfs_dirent * cursor = file->private_data;
552 mutex_lock(&dentry->d_inode->i_mutex);
553 list_del_init(&cursor->s_sibling);
554 mutex_unlock(&dentry->d_inode->i_mutex);
556 release_sysfs_dirent(cursor);
561 /* Relationship between s_mode and the DT_xxx types */
562 static inline unsigned char dt_type(struct sysfs_dirent *sd)
564 return (sd->s_mode >> 12) & 15;
567 static int sysfs_readdir(struct file * filp, void * dirent, filldir_t filldir)
569 struct dentry *dentry = filp->f_path.dentry;
570 struct sysfs_dirent * parent_sd = dentry->d_fsdata;
571 struct sysfs_dirent *cursor = filp->private_data;
572 struct list_head *p, *q = &cursor->s_sibling;
578 ino = parent_sd->s_ino;
579 if (filldir(dirent, ".", 1, i, ino, DT_DIR) < 0)
585 ino = parent_ino(dentry);
586 if (filldir(dirent, "..", 2, i, ino, DT_DIR) < 0)
592 if (filp->f_pos == 2)
593 list_move(q, &parent_sd->s_children);
595 for (p=q->next; p!= &parent_sd->s_children; p=p->next) {
596 struct sysfs_dirent *next;
600 next = list_entry(p, struct sysfs_dirent,
602 if (!next->s_element)
605 name = sysfs_get_name(next);
609 if (filldir(dirent, name, len, filp->f_pos, ino,
621 static loff_t sysfs_dir_lseek(struct file * file, loff_t offset, int origin)
623 struct dentry * dentry = file->f_path.dentry;
625 mutex_lock(&dentry->d_inode->i_mutex);
628 offset += file->f_pos;
633 mutex_unlock(&file->f_path.dentry->d_inode->i_mutex);
636 if (offset != file->f_pos) {
637 file->f_pos = offset;
638 if (file->f_pos >= 2) {
639 struct sysfs_dirent *sd = dentry->d_fsdata;
640 struct sysfs_dirent *cursor = file->private_data;
642 loff_t n = file->f_pos - 2;
644 list_del(&cursor->s_sibling);
645 p = sd->s_children.next;
646 while (n && p != &sd->s_children) {
647 struct sysfs_dirent *next;
648 next = list_entry(p, struct sysfs_dirent,
654 list_add_tail(&cursor->s_sibling, p);
657 mutex_unlock(&dentry->d_inode->i_mutex);
663 * sysfs_make_shadowed_dir - Setup so a directory can be shadowed
664 * @kobj: object we're creating shadow of.
667 int sysfs_make_shadowed_dir(struct kobject *kobj,
668 void * (*follow_link)(struct dentry *, struct nameidata *))
671 struct inode_operations *i_op;
673 inode = kobj->dentry->d_inode;
674 if (inode->i_op != &sysfs_dir_inode_operations)
677 i_op = kmalloc(sizeof(*i_op), GFP_KERNEL);
681 memcpy(i_op, &sysfs_dir_inode_operations, sizeof(*i_op));
682 i_op->follow_link = follow_link;
684 /* Locking of inode->i_op?
685 * Since setting i_op is a single word write and they
686 * are atomic we should be ok here.
693 * sysfs_create_shadow_dir - create a shadow directory for an object.
694 * @kobj: object we're creating directory for.
696 * sysfs_make_shadowed_dir must already have been called on this
700 struct dentry *sysfs_create_shadow_dir(struct kobject *kobj)
702 struct sysfs_dirent *sd;
703 struct dentry *parent, *dir, *shadow;
707 inode = dir->d_inode;
708 parent = dir->d_parent;
709 shadow = ERR_PTR(-EINVAL);
710 if (!sysfs_is_shadowed_inode(inode))
713 shadow = d_alloc(parent, &dir->d_name);
717 sd = __sysfs_make_dirent(shadow, kobj, inode->i_mode, SYSFS_DIR);
721 d_instantiate(shadow, igrab(inode));
723 inc_nlink(parent->d_inode);
724 shadow->d_op = &sysfs_dentry_ops;
726 dget(shadow); /* Extra count - pin the dentry in core */
732 shadow = ERR_PTR(-ENOMEM);
737 * sysfs_remove_shadow_dir - remove an object's directory.
738 * @shadow: dentry of shadow directory
740 * The only thing special about this is that we remove any files in
741 * the directory before we remove the directory, and we've inlined
742 * what used to be sysfs_rmdir() below, instead of calling separately.
745 void sysfs_remove_shadow_dir(struct dentry *shadow)
747 __sysfs_remove_dir(shadow);
750 const struct file_operations sysfs_dir_operations = {
751 .open = sysfs_dir_open,
752 .release = sysfs_dir_close,
753 .llseek = sysfs_dir_lseek,
754 .read = generic_read_dir,
755 .readdir = sysfs_readdir,