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 <asm/semaphore.h>
15 DECLARE_RWSEM(sysfs_rename_sem);
16 spinlock_t sysfs_lock = SPIN_LOCK_UNLOCKED;
18 static void sysfs_d_iput(struct dentry * dentry, struct inode * inode)
20 struct sysfs_dirent * sd = dentry->d_fsdata;
23 /* sd->s_dentry is protected with sysfs_lock. This
24 * allows sysfs_drop_dentry() to dereference it.
26 spin_lock(&sysfs_lock);
28 /* The dentry might have been deleted or another
29 * lookup could have happened updating sd->s_dentry to
30 * point the new dentry. Ignore if it isn't pointing
33 if (sd->s_dentry == dentry)
35 spin_unlock(&sysfs_lock);
41 static struct dentry_operations sysfs_dentry_ops = {
42 .d_iput = sysfs_d_iput,
45 static unsigned int sysfs_inode_counter;
46 ino_t sysfs_get_inum(void)
48 if (unlikely(sysfs_inode_counter < 3))
49 sysfs_inode_counter = 3;
50 return sysfs_inode_counter++;
54 * Allocates a new sysfs_dirent and links it to the parent sysfs_dirent
56 static struct sysfs_dirent * __sysfs_new_dirent(void * element)
58 struct sysfs_dirent * sd;
60 sd = kmem_cache_zalloc(sysfs_dir_cachep, GFP_KERNEL);
64 sd->s_ino = sysfs_get_inum();
65 atomic_set(&sd->s_count, 1);
66 atomic_set(&sd->s_event, 1);
67 INIT_LIST_HEAD(&sd->s_children);
68 INIT_LIST_HEAD(&sd->s_sibling);
69 sd->s_element = element;
74 static void __sysfs_list_dirent(struct sysfs_dirent *parent_sd,
75 struct sysfs_dirent *sd)
78 list_add(&sd->s_sibling, &parent_sd->s_children);
81 static struct sysfs_dirent * sysfs_new_dirent(struct sysfs_dirent *parent_sd,
84 struct sysfs_dirent *sd;
85 sd = __sysfs_new_dirent(element);
86 __sysfs_list_dirent(parent_sd, sd);
92 * Return -EEXIST if there is already a sysfs element with the same name for
95 * called with parent inode's i_mutex held
97 int sysfs_dirent_exist(struct sysfs_dirent *parent_sd,
98 const unsigned char *new)
100 struct sysfs_dirent * sd;
102 list_for_each_entry(sd, &parent_sd->s_children, s_sibling) {
104 const unsigned char *existing = sysfs_get_name(sd);
105 if (strcmp(existing, new))
116 static struct sysfs_dirent *
117 __sysfs_make_dirent(struct dentry *dentry, void *element, mode_t mode, int type)
119 struct sysfs_dirent * sd;
121 sd = __sysfs_new_dirent(element);
127 sd->s_dentry = dentry;
129 dentry->d_fsdata = sysfs_get(sd);
130 dentry->d_op = &sysfs_dentry_ops;
137 int sysfs_make_dirent(struct sysfs_dirent * parent_sd, struct dentry * dentry,
138 void * element, umode_t mode, int type)
140 struct sysfs_dirent *sd;
142 sd = __sysfs_make_dirent(dentry, element, mode, type);
143 __sysfs_list_dirent(parent_sd, sd);
145 return sd ? 0 : -ENOMEM;
148 static int init_dir(struct inode * inode)
150 inode->i_op = &sysfs_dir_inode_operations;
151 inode->i_fop = &sysfs_dir_operations;
153 /* directory inodes start off with i_nlink == 2 (for "." entry) */
158 static int init_file(struct inode * inode)
160 inode->i_size = PAGE_SIZE;
161 inode->i_fop = &sysfs_file_operations;
165 static int init_symlink(struct inode * inode)
167 inode->i_op = &sysfs_symlink_inode_operations;
171 static int create_dir(struct kobject * k, struct dentry * p,
172 const char * n, struct dentry ** d)
175 umode_t mode = S_IFDIR| S_IRWXU | S_IRUGO | S_IXUGO;
177 mutex_lock(&p->d_inode->i_mutex);
178 *d = lookup_one_len(n, p, strlen(n));
180 if (sysfs_dirent_exist(p->d_fsdata, n))
183 error = sysfs_make_dirent(p->d_fsdata, *d, k, mode,
186 error = sysfs_create(*d, mode, init_dir);
188 inc_nlink(p->d_inode);
189 (*d)->d_op = &sysfs_dentry_ops;
193 if (error && (error != -EEXIST)) {
194 struct sysfs_dirent *sd = (*d)->d_fsdata;
196 list_del_init(&sd->s_sibling);
204 mutex_unlock(&p->d_inode->i_mutex);
209 int sysfs_create_subdir(struct kobject * k, const char * n, struct dentry ** d)
211 return create_dir(k,k->dentry,n,d);
215 * sysfs_create_dir - create a directory for an object.
216 * @kobj: object we're creating directory for.
217 * @shadow_parent: parent parent object.
220 int sysfs_create_dir(struct kobject * kobj, struct dentry *shadow_parent)
222 struct dentry * dentry = NULL;
223 struct dentry * parent;
229 parent = shadow_parent;
230 else if (kobj->parent)
231 parent = kobj->parent->dentry;
232 else if (sysfs_mount && sysfs_mount->mnt_sb)
233 parent = sysfs_mount->mnt_sb->s_root;
237 error = create_dir(kobj,parent,kobject_name(kobj),&dentry);
239 kobj->dentry = dentry;
243 /* attaches attribute's sysfs_dirent to the dentry corresponding to the
246 static int sysfs_attach_attr(struct sysfs_dirent * sd, struct dentry * dentry)
248 struct attribute * attr = NULL;
249 struct bin_attribute * bin_attr = NULL;
250 int (* init) (struct inode *) = NULL;
253 if (sd->s_type & SYSFS_KOBJ_BIN_ATTR) {
254 bin_attr = sd->s_element;
255 attr = &bin_attr->attr;
257 attr = sd->s_element;
261 dentry->d_fsdata = sysfs_get(sd);
262 /* protect sd->s_dentry against sysfs_d_iput */
263 spin_lock(&sysfs_lock);
264 sd->s_dentry = dentry;
265 spin_unlock(&sysfs_lock);
266 error = sysfs_create(dentry, (attr->mode & S_IALLUGO) | S_IFREG, init);
273 dentry->d_inode->i_size = bin_attr->size;
274 dentry->d_inode->i_fop = &bin_fops;
276 dentry->d_op = &sysfs_dentry_ops;
282 static int sysfs_attach_link(struct sysfs_dirent * sd, struct dentry * dentry)
286 dentry->d_fsdata = sysfs_get(sd);
287 /* protect sd->s_dentry against sysfs_d_iput */
288 spin_lock(&sysfs_lock);
289 sd->s_dentry = dentry;
290 spin_unlock(&sysfs_lock);
291 err = sysfs_create(dentry, S_IFLNK|S_IRWXUGO, init_symlink);
293 dentry->d_op = &sysfs_dentry_ops;
301 static struct dentry * sysfs_lookup(struct inode *dir, struct dentry *dentry,
302 struct nameidata *nd)
304 struct sysfs_dirent * parent_sd = dentry->d_parent->d_fsdata;
305 struct sysfs_dirent * sd;
308 list_for_each_entry(sd, &parent_sd->s_children, s_sibling) {
309 if (sd->s_type & SYSFS_NOT_PINNED) {
310 const unsigned char * name = sysfs_get_name(sd);
312 if (strcmp(name, dentry->d_name.name))
315 if (sd->s_type & SYSFS_KOBJ_LINK)
316 err = sysfs_attach_link(sd, dentry);
318 err = sysfs_attach_attr(sd, dentry);
326 const struct inode_operations sysfs_dir_inode_operations = {
327 .lookup = sysfs_lookup,
328 .setattr = sysfs_setattr,
331 static void remove_dir(struct dentry * d)
333 struct dentry * parent = dget(d->d_parent);
334 struct sysfs_dirent * sd;
336 mutex_lock(&parent->d_inode->i_mutex);
339 list_del_init(&sd->s_sibling);
342 simple_rmdir(parent->d_inode,d);
344 pr_debug(" o %s removing done (%d)\n",d->d_name.name,
345 atomic_read(&d->d_count));
347 mutex_unlock(&parent->d_inode->i_mutex);
351 void sysfs_remove_subdir(struct dentry * d)
357 static void __sysfs_remove_dir(struct dentry *dentry)
359 struct sysfs_dirent * parent_sd;
360 struct sysfs_dirent * sd, * tmp;
366 pr_debug("sysfs %s: removing dir\n",dentry->d_name.name);
367 mutex_lock(&dentry->d_inode->i_mutex);
368 parent_sd = dentry->d_fsdata;
369 list_for_each_entry_safe(sd, tmp, &parent_sd->s_children, s_sibling) {
370 if (!sd->s_element || !(sd->s_type & SYSFS_NOT_PINNED))
372 list_del_init(&sd->s_sibling);
373 sysfs_drop_dentry(sd, dentry);
376 mutex_unlock(&dentry->d_inode->i_mutex);
380 * Drop reference from dget() on entrance.
386 * sysfs_remove_dir - remove an object's directory.
389 * The only thing special about this is that we remove any files in
390 * the directory before we remove the directory, and we've inlined
391 * what used to be sysfs_rmdir() below, instead of calling separately.
394 void sysfs_remove_dir(struct kobject * kobj)
396 __sysfs_remove_dir(kobj->dentry);
400 int sysfs_rename_dir(struct kobject * kobj, struct dentry *new_parent,
401 const char *new_name)
404 struct dentry * new_dentry;
409 down_write(&sysfs_rename_sem);
410 mutex_lock(&new_parent->d_inode->i_mutex);
412 new_dentry = lookup_one_len(new_name, new_parent, strlen(new_name));
413 if (!IS_ERR(new_dentry)) {
414 /* By allowing two different directories with the
415 * same d_parent we allow this routine to move
416 * between different shadows of the same directory
418 if (kobj->dentry->d_parent->d_inode != new_parent->d_inode)
420 else if (new_dentry->d_parent->d_inode != new_parent->d_inode)
422 else if (new_dentry == kobj->dentry)
424 else if (!new_dentry->d_inode) {
425 error = kobject_set_name(kobj, "%s", new_name);
427 struct sysfs_dirent *sd, *parent_sd;
429 d_add(new_dentry, NULL);
430 d_move(kobj->dentry, new_dentry);
432 sd = kobj->dentry->d_fsdata;
433 parent_sd = new_parent->d_fsdata;
435 list_del_init(&sd->s_sibling);
436 list_add(&sd->s_sibling, &parent_sd->s_children);
444 mutex_unlock(&new_parent->d_inode->i_mutex);
445 up_write(&sysfs_rename_sem);
450 int sysfs_move_dir(struct kobject *kobj, struct kobject *new_parent)
452 struct dentry *old_parent_dentry, *new_parent_dentry, *new_dentry;
453 struct sysfs_dirent *new_parent_sd, *sd;
456 old_parent_dentry = kobj->parent ?
457 kobj->parent->dentry : sysfs_mount->mnt_sb->s_root;
458 new_parent_dentry = new_parent ?
459 new_parent->dentry : sysfs_mount->mnt_sb->s_root;
461 if (old_parent_dentry->d_inode == new_parent_dentry->d_inode)
462 return 0; /* nothing to move */
464 mutex_lock(&old_parent_dentry->d_inode->i_mutex);
465 if (!mutex_trylock(&new_parent_dentry->d_inode->i_mutex)) {
466 mutex_unlock(&old_parent_dentry->d_inode->i_mutex);
470 new_parent_sd = new_parent_dentry->d_fsdata;
471 sd = kobj->dentry->d_fsdata;
473 new_dentry = lookup_one_len(kobj->name, new_parent_dentry,
475 if (IS_ERR(new_dentry)) {
476 error = PTR_ERR(new_dentry);
480 d_add(new_dentry, NULL);
481 d_move(kobj->dentry, new_dentry);
484 /* Remove from old parent's list and insert into new parent's list. */
485 list_del_init(&sd->s_sibling);
486 list_add(&sd->s_sibling, &new_parent_sd->s_children);
489 mutex_unlock(&new_parent_dentry->d_inode->i_mutex);
490 mutex_unlock(&old_parent_dentry->d_inode->i_mutex);
495 static int sysfs_dir_open(struct inode *inode, struct file *file)
497 struct dentry * dentry = file->f_path.dentry;
498 struct sysfs_dirent * parent_sd = dentry->d_fsdata;
500 mutex_lock(&dentry->d_inode->i_mutex);
501 file->private_data = sysfs_new_dirent(parent_sd, NULL);
502 mutex_unlock(&dentry->d_inode->i_mutex);
504 return file->private_data ? 0 : -ENOMEM;
508 static int sysfs_dir_close(struct inode *inode, struct file *file)
510 struct dentry * dentry = file->f_path.dentry;
511 struct sysfs_dirent * cursor = file->private_data;
513 mutex_lock(&dentry->d_inode->i_mutex);
514 list_del_init(&cursor->s_sibling);
515 mutex_unlock(&dentry->d_inode->i_mutex);
517 release_sysfs_dirent(cursor);
522 /* Relationship between s_mode and the DT_xxx types */
523 static inline unsigned char dt_type(struct sysfs_dirent *sd)
525 return (sd->s_mode >> 12) & 15;
528 static int sysfs_readdir(struct file * filp, void * dirent, filldir_t filldir)
530 struct dentry *dentry = filp->f_path.dentry;
531 struct sysfs_dirent * parent_sd = dentry->d_fsdata;
532 struct sysfs_dirent *cursor = filp->private_data;
533 struct list_head *p, *q = &cursor->s_sibling;
539 ino = parent_sd->s_ino;
540 if (filldir(dirent, ".", 1, i, ino, DT_DIR) < 0)
546 ino = parent_ino(dentry);
547 if (filldir(dirent, "..", 2, i, ino, DT_DIR) < 0)
553 if (filp->f_pos == 2)
554 list_move(q, &parent_sd->s_children);
556 for (p=q->next; p!= &parent_sd->s_children; p=p->next) {
557 struct sysfs_dirent *next;
561 next = list_entry(p, struct sysfs_dirent,
563 if (!next->s_element)
566 name = sysfs_get_name(next);
570 if (filldir(dirent, name, len, filp->f_pos, ino,
582 static loff_t sysfs_dir_lseek(struct file * file, loff_t offset, int origin)
584 struct dentry * dentry = file->f_path.dentry;
586 mutex_lock(&dentry->d_inode->i_mutex);
589 offset += file->f_pos;
594 mutex_unlock(&file->f_path.dentry->d_inode->i_mutex);
597 if (offset != file->f_pos) {
598 file->f_pos = offset;
599 if (file->f_pos >= 2) {
600 struct sysfs_dirent *sd = dentry->d_fsdata;
601 struct sysfs_dirent *cursor = file->private_data;
603 loff_t n = file->f_pos - 2;
605 list_del(&cursor->s_sibling);
606 p = sd->s_children.next;
607 while (n && p != &sd->s_children) {
608 struct sysfs_dirent *next;
609 next = list_entry(p, struct sysfs_dirent,
615 list_add_tail(&cursor->s_sibling, p);
618 mutex_unlock(&dentry->d_inode->i_mutex);
624 * sysfs_make_shadowed_dir - Setup so a directory can be shadowed
625 * @kobj: object we're creating shadow of.
628 int sysfs_make_shadowed_dir(struct kobject *kobj,
629 void * (*follow_link)(struct dentry *, struct nameidata *))
632 struct inode_operations *i_op;
634 inode = kobj->dentry->d_inode;
635 if (inode->i_op != &sysfs_dir_inode_operations)
638 i_op = kmalloc(sizeof(*i_op), GFP_KERNEL);
642 memcpy(i_op, &sysfs_dir_inode_operations, sizeof(*i_op));
643 i_op->follow_link = follow_link;
645 /* Locking of inode->i_op?
646 * Since setting i_op is a single word write and they
647 * are atomic we should be ok here.
654 * sysfs_create_shadow_dir - create a shadow directory for an object.
655 * @kobj: object we're creating directory for.
657 * sysfs_make_shadowed_dir must already have been called on this
661 struct dentry *sysfs_create_shadow_dir(struct kobject *kobj)
663 struct sysfs_dirent *sd;
664 struct dentry *parent, *dir, *shadow;
668 inode = dir->d_inode;
669 parent = dir->d_parent;
670 shadow = ERR_PTR(-EINVAL);
671 if (!sysfs_is_shadowed_inode(inode))
674 shadow = d_alloc(parent, &dir->d_name);
678 sd = __sysfs_make_dirent(shadow, kobj, inode->i_mode, SYSFS_DIR);
682 d_instantiate(shadow, igrab(inode));
684 inc_nlink(parent->d_inode);
685 shadow->d_op = &sysfs_dentry_ops;
687 dget(shadow); /* Extra count - pin the dentry in core */
693 shadow = ERR_PTR(-ENOMEM);
698 * sysfs_remove_shadow_dir - remove an object's directory.
699 * @shadow: dentry of shadow directory
701 * The only thing special about this is that we remove any files in
702 * the directory before we remove the directory, and we've inlined
703 * what used to be sysfs_rmdir() below, instead of calling separately.
706 void sysfs_remove_shadow_dir(struct dentry *shadow)
708 __sysfs_remove_dir(shadow);
711 const struct file_operations sysfs_dir_operations = {
712 .open = sysfs_dir_open,
713 .release = sysfs_dir_close,
714 .llseek = sysfs_dir_lseek,
715 .read = generic_read_dir,
716 .readdir = sysfs_readdir,