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;
18 spinlock_t kobj_sysfs_assoc_lock = SPIN_LOCK_UNLOCKED;
20 static spinlock_t sysfs_ino_lock = SPIN_LOCK_UNLOCKED;
21 static DEFINE_IDA(sysfs_ino_ida);
23 static int sysfs_alloc_ino(ino_t *pino)
28 spin_lock(&sysfs_ino_lock);
29 rc = ida_get_new_above(&sysfs_ino_ida, 2, &ino);
30 spin_unlock(&sysfs_ino_lock);
33 if (ida_pre_get(&sysfs_ino_ida, GFP_KERNEL))
42 static void sysfs_free_ino(ino_t ino)
44 spin_lock(&sysfs_ino_lock);
45 ida_remove(&sysfs_ino_ida, ino);
46 spin_unlock(&sysfs_ino_lock);
49 void release_sysfs_dirent(struct sysfs_dirent * sd)
51 struct sysfs_dirent *parent_sd;
54 parent_sd = sd->s_parent;
56 /* If @sd is being released after deletion, s_active is write
57 * locked. If @sd is cursor for directory walk or being
58 * released prematurely, s_active has no reader or writer.
60 * sysfs_deactivate() lies to lockdep that s_active is
61 * unlocked immediately. Lie one more time to cover the
64 if (!down_write_trylock(&sd->s_active))
65 rwsem_acquire(&sd->s_active.dep_map,
66 SYSFS_S_ACTIVE_DEACTIVATE, 0, _RET_IP_);
67 up_write(&sd->s_active);
69 if (sd->s_type & SYSFS_KOBJ_LINK)
70 sysfs_put(sd->s_elem.symlink.target_sd);
71 if (sd->s_type & SYSFS_COPY_NAME)
74 sysfs_free_ino(sd->s_ino);
75 kmem_cache_free(sysfs_dir_cachep, sd);
78 if (sd && atomic_dec_and_test(&sd->s_count))
82 static void sysfs_d_iput(struct dentry * dentry, struct inode * inode)
84 struct sysfs_dirent * sd = dentry->d_fsdata;
87 /* sd->s_dentry is protected with sysfs_lock. This
88 * allows sysfs_drop_dentry() to dereference it.
90 spin_lock(&sysfs_lock);
92 /* The dentry might have been deleted or another
93 * lookup could have happened updating sd->s_dentry to
94 * point the new dentry. Ignore if it isn't pointing
97 if (sd->s_dentry == dentry)
99 spin_unlock(&sysfs_lock);
105 static struct dentry_operations sysfs_dentry_ops = {
106 .d_iput = sysfs_d_iput,
109 struct sysfs_dirent *sysfs_new_dirent(const char *name, umode_t mode, int type)
111 char *dup_name = NULL;
112 struct sysfs_dirent *sd = NULL;
114 if (type & SYSFS_COPY_NAME) {
115 name = dup_name = kstrdup(name, GFP_KERNEL);
120 sd = kmem_cache_zalloc(sysfs_dir_cachep, GFP_KERNEL);
124 if (sysfs_alloc_ino(&sd->s_ino))
127 atomic_set(&sd->s_count, 1);
128 atomic_set(&sd->s_event, 1);
129 init_rwsem(&sd->s_active);
130 INIT_LIST_HEAD(&sd->s_children);
131 INIT_LIST_HEAD(&sd->s_sibling);
141 kmem_cache_free(sysfs_dir_cachep, sd);
145 static void sysfs_attach_dentry(struct sysfs_dirent *sd, struct dentry *dentry)
147 dentry->d_op = &sysfs_dentry_ops;
148 dentry->d_fsdata = sysfs_get(sd);
150 /* protect sd->s_dentry against sysfs_d_iput */
151 spin_lock(&sysfs_lock);
152 sd->s_dentry = dentry;
153 spin_unlock(&sysfs_lock);
158 void sysfs_attach_dirent(struct sysfs_dirent *sd,
159 struct sysfs_dirent *parent_sd, struct dentry *dentry)
162 sysfs_attach_dentry(sd, dentry);
165 sd->s_parent = sysfs_get(parent_sd);
166 list_add(&sd->s_sibling, &parent_sd->s_children);
172 * Return -EEXIST if there is already a sysfs element with the same name for
175 * called with parent inode's i_mutex held
177 int sysfs_dirent_exist(struct sysfs_dirent *parent_sd,
178 const unsigned char *new)
180 struct sysfs_dirent * sd;
182 list_for_each_entry(sd, &parent_sd->s_children, s_sibling) {
184 if (strcmp(sd->s_name, new))
194 static int init_dir(struct inode * inode)
196 inode->i_op = &sysfs_dir_inode_operations;
197 inode->i_fop = &sysfs_dir_operations;
199 /* directory inodes start off with i_nlink == 2 (for "." entry) */
204 static int init_file(struct inode * inode)
206 inode->i_size = PAGE_SIZE;
207 inode->i_fop = &sysfs_file_operations;
211 static int init_symlink(struct inode * inode)
213 inode->i_op = &sysfs_symlink_inode_operations;
217 static int create_dir(struct kobject *kobj, struct dentry *parent,
218 const char *name, struct dentry **p_dentry)
221 umode_t mode = S_IFDIR| S_IRWXU | S_IRUGO | S_IXUGO;
222 struct dentry *dentry;
223 struct sysfs_dirent *sd;
225 mutex_lock(&parent->d_inode->i_mutex);
227 dentry = lookup_one_len(name, parent, strlen(name));
228 if (IS_ERR(dentry)) {
229 error = PTR_ERR(dentry);
234 if (sysfs_dirent_exist(parent->d_fsdata, name))
238 sd = sysfs_new_dirent(name, mode, SYSFS_DIR);
241 sd->s_elem.dir.kobj = kobj;
243 error = sysfs_create(sd, dentry, mode, init_dir);
247 inc_nlink(parent->d_inode);
248 sysfs_attach_dirent(sd, parent->d_fsdata, dentry);
255 list_del_init(&sd->s_sibling);
262 mutex_unlock(&parent->d_inode->i_mutex);
267 int sysfs_create_subdir(struct kobject * k, const char * n, struct dentry ** d)
269 return create_dir(k,k->dentry,n,d);
273 * sysfs_create_dir - create a directory for an object.
274 * @kobj: object we're creating directory for.
275 * @shadow_parent: parent parent object.
278 int sysfs_create_dir(struct kobject * kobj, struct dentry *shadow_parent)
280 struct dentry * dentry = NULL;
281 struct dentry * parent;
287 parent = shadow_parent;
288 else if (kobj->parent)
289 parent = kobj->parent->dentry;
290 else if (sysfs_mount && sysfs_mount->mnt_sb)
291 parent = sysfs_mount->mnt_sb->s_root;
295 error = create_dir(kobj,parent,kobject_name(kobj),&dentry);
297 kobj->dentry = dentry;
301 /* attaches attribute's sysfs_dirent to the dentry corresponding to the
304 static int sysfs_attach_attr(struct sysfs_dirent * sd, struct dentry * dentry)
306 struct attribute * attr = NULL;
307 struct bin_attribute * bin_attr = NULL;
308 int (* init) (struct inode *) = NULL;
311 if (sd->s_type & SYSFS_KOBJ_BIN_ATTR) {
312 bin_attr = sd->s_elem.bin_attr.bin_attr;
313 attr = &bin_attr->attr;
315 attr = sd->s_elem.attr.attr;
319 error = sysfs_create(sd, dentry,
320 (attr->mode & S_IALLUGO) | S_IFREG, init);
325 dentry->d_inode->i_size = bin_attr->size;
326 dentry->d_inode->i_fop = &bin_fops;
329 sysfs_attach_dentry(sd, dentry);
334 static int sysfs_attach_link(struct sysfs_dirent * sd, struct dentry * dentry)
338 err = sysfs_create(sd, dentry, S_IFLNK|S_IRWXUGO, init_symlink);
340 sysfs_attach_dentry(sd, dentry);
345 static struct dentry * sysfs_lookup(struct inode *dir, struct dentry *dentry,
346 struct nameidata *nd)
348 struct sysfs_dirent * parent_sd = dentry->d_parent->d_fsdata;
349 struct sysfs_dirent * sd;
352 list_for_each_entry(sd, &parent_sd->s_children, s_sibling) {
353 if (sd->s_type & SYSFS_NOT_PINNED) {
354 if (strcmp(sd->s_name, dentry->d_name.name))
357 if (sd->s_type & SYSFS_KOBJ_LINK)
358 err = sysfs_attach_link(sd, dentry);
360 err = sysfs_attach_attr(sd, dentry);
368 const struct inode_operations sysfs_dir_inode_operations = {
369 .lookup = sysfs_lookup,
370 .setattr = sysfs_setattr,
373 static void remove_dir(struct dentry * d)
375 struct dentry *parent = d->d_parent;
376 struct sysfs_dirent *sd = d->d_fsdata;
378 mutex_lock(&parent->d_inode->i_mutex);
380 list_del_init(&sd->s_sibling);
382 pr_debug(" o %s removing done (%d)\n",d->d_name.name,
383 atomic_read(&d->d_count));
385 mutex_unlock(&parent->d_inode->i_mutex);
387 sysfs_drop_dentry(sd);
388 sysfs_deactivate(sd);
392 void sysfs_remove_subdir(struct dentry * d)
398 static void __sysfs_remove_dir(struct dentry *dentry)
401 struct sysfs_dirent * parent_sd;
402 struct sysfs_dirent * sd, * tmp;
407 pr_debug("sysfs %s: removing dir\n",dentry->d_name.name);
408 mutex_lock(&dentry->d_inode->i_mutex);
409 parent_sd = dentry->d_fsdata;
410 list_for_each_entry_safe(sd, tmp, &parent_sd->s_children, s_sibling) {
411 if (!sd->s_type || !(sd->s_type & SYSFS_NOT_PINNED))
413 list_move(&sd->s_sibling, &removed);
415 mutex_unlock(&dentry->d_inode->i_mutex);
417 list_for_each_entry_safe(sd, tmp, &removed, s_sibling) {
418 list_del_init(&sd->s_sibling);
419 sysfs_drop_dentry(sd);
420 sysfs_deactivate(sd);
428 * sysfs_remove_dir - remove an object's directory.
431 * The only thing special about this is that we remove any files in
432 * the directory before we remove the directory, and we've inlined
433 * what used to be sysfs_rmdir() below, instead of calling separately.
436 void sysfs_remove_dir(struct kobject * kobj)
438 struct dentry *d = kobj->dentry;
440 spin_lock(&kobj_sysfs_assoc_lock);
442 spin_unlock(&kobj_sysfs_assoc_lock);
444 __sysfs_remove_dir(d);
447 int sysfs_rename_dir(struct kobject * kobj, struct dentry *new_parent,
448 const char *new_name)
450 struct sysfs_dirent *sd = kobj->dentry->d_fsdata;
451 struct sysfs_dirent *parent_sd = new_parent->d_fsdata;
452 struct dentry *new_dentry;
459 down_write(&sysfs_rename_sem);
460 mutex_lock(&new_parent->d_inode->i_mutex);
462 new_dentry = lookup_one_len(new_name, new_parent, strlen(new_name));
463 if (IS_ERR(new_dentry)) {
464 error = PTR_ERR(new_dentry);
468 /* By allowing two different directories with the same
469 * d_parent we allow this routine to move between different
470 * shadows of the same directory
473 if (kobj->dentry->d_parent->d_inode != new_parent->d_inode ||
474 new_dentry->d_parent->d_inode != new_parent->d_inode ||
475 new_dentry == kobj->dentry)
479 if (new_dentry->d_inode)
482 /* rename kobject and sysfs_dirent */
484 new_name = dup_name = kstrdup(new_name, GFP_KERNEL);
488 error = kobject_set_name(kobj, "%s", new_name);
493 sd->s_name = new_name;
495 /* move under the new parent */
496 d_add(new_dentry, NULL);
497 d_move(kobj->dentry, new_dentry);
499 list_del_init(&sd->s_sibling);
500 list_add(&sd->s_sibling, &parent_sd->s_children);
512 mutex_unlock(&new_parent->d_inode->i_mutex);
513 up_write(&sysfs_rename_sem);
517 int sysfs_move_dir(struct kobject *kobj, struct kobject *new_parent)
519 struct dentry *old_parent_dentry, *new_parent_dentry, *new_dentry;
520 struct sysfs_dirent *new_parent_sd, *sd;
523 old_parent_dentry = kobj->parent ?
524 kobj->parent->dentry : sysfs_mount->mnt_sb->s_root;
525 new_parent_dentry = new_parent ?
526 new_parent->dentry : sysfs_mount->mnt_sb->s_root;
528 if (old_parent_dentry->d_inode == new_parent_dentry->d_inode)
529 return 0; /* nothing to move */
531 mutex_lock(&old_parent_dentry->d_inode->i_mutex);
532 if (!mutex_trylock(&new_parent_dentry->d_inode->i_mutex)) {
533 mutex_unlock(&old_parent_dentry->d_inode->i_mutex);
537 new_parent_sd = new_parent_dentry->d_fsdata;
538 sd = kobj->dentry->d_fsdata;
540 new_dentry = lookup_one_len(kobj->name, new_parent_dentry,
542 if (IS_ERR(new_dentry)) {
543 error = PTR_ERR(new_dentry);
547 d_add(new_dentry, NULL);
548 d_move(kobj->dentry, new_dentry);
551 /* Remove from old parent's list and insert into new parent's list. */
552 list_del_init(&sd->s_sibling);
553 list_add(&sd->s_sibling, &new_parent_sd->s_children);
556 mutex_unlock(&new_parent_dentry->d_inode->i_mutex);
557 mutex_unlock(&old_parent_dentry->d_inode->i_mutex);
562 static int sysfs_dir_open(struct inode *inode, struct file *file)
564 struct dentry * dentry = file->f_path.dentry;
565 struct sysfs_dirent * parent_sd = dentry->d_fsdata;
566 struct sysfs_dirent * sd;
568 mutex_lock(&dentry->d_inode->i_mutex);
569 sd = sysfs_new_dirent("_DIR_", 0, 0);
571 sysfs_attach_dirent(sd, parent_sd, NULL);
572 mutex_unlock(&dentry->d_inode->i_mutex);
574 file->private_data = sd;
575 return sd ? 0 : -ENOMEM;
578 static int sysfs_dir_close(struct inode *inode, struct file *file)
580 struct dentry * dentry = file->f_path.dentry;
581 struct sysfs_dirent * cursor = file->private_data;
583 mutex_lock(&dentry->d_inode->i_mutex);
584 list_del_init(&cursor->s_sibling);
585 mutex_unlock(&dentry->d_inode->i_mutex);
587 release_sysfs_dirent(cursor);
592 /* Relationship between s_mode and the DT_xxx types */
593 static inline unsigned char dt_type(struct sysfs_dirent *sd)
595 return (sd->s_mode >> 12) & 15;
598 static int sysfs_readdir(struct file * filp, void * dirent, filldir_t filldir)
600 struct dentry *dentry = filp->f_path.dentry;
601 struct sysfs_dirent * parent_sd = dentry->d_fsdata;
602 struct sysfs_dirent *cursor = filp->private_data;
603 struct list_head *p, *q = &cursor->s_sibling;
609 ino = parent_sd->s_ino;
610 if (filldir(dirent, ".", 1, i, ino, DT_DIR) < 0)
616 if (parent_sd->s_parent)
617 ino = parent_sd->s_parent->s_ino;
619 ino = parent_sd->s_ino;
620 if (filldir(dirent, "..", 2, i, ino, DT_DIR) < 0)
626 if (filp->f_pos == 2)
627 list_move(q, &parent_sd->s_children);
629 for (p=q->next; p!= &parent_sd->s_children; p=p->next) {
630 struct sysfs_dirent *next;
634 next = list_entry(p, struct sysfs_dirent,
643 if (filldir(dirent, name, len, filp->f_pos, ino,
655 static loff_t sysfs_dir_lseek(struct file * file, loff_t offset, int origin)
657 struct dentry * dentry = file->f_path.dentry;
659 mutex_lock(&dentry->d_inode->i_mutex);
662 offset += file->f_pos;
667 mutex_unlock(&file->f_path.dentry->d_inode->i_mutex);
670 if (offset != file->f_pos) {
671 file->f_pos = offset;
672 if (file->f_pos >= 2) {
673 struct sysfs_dirent *sd = dentry->d_fsdata;
674 struct sysfs_dirent *cursor = file->private_data;
676 loff_t n = file->f_pos - 2;
678 list_del(&cursor->s_sibling);
679 p = sd->s_children.next;
680 while (n && p != &sd->s_children) {
681 struct sysfs_dirent *next;
682 next = list_entry(p, struct sysfs_dirent,
688 list_add_tail(&cursor->s_sibling, p);
691 mutex_unlock(&dentry->d_inode->i_mutex);
697 * sysfs_make_shadowed_dir - Setup so a directory can be shadowed
698 * @kobj: object we're creating shadow of.
701 int sysfs_make_shadowed_dir(struct kobject *kobj,
702 void * (*follow_link)(struct dentry *, struct nameidata *))
705 struct inode_operations *i_op;
707 inode = kobj->dentry->d_inode;
708 if (inode->i_op != &sysfs_dir_inode_operations)
711 i_op = kmalloc(sizeof(*i_op), GFP_KERNEL);
715 memcpy(i_op, &sysfs_dir_inode_operations, sizeof(*i_op));
716 i_op->follow_link = follow_link;
718 /* Locking of inode->i_op?
719 * Since setting i_op is a single word write and they
720 * are atomic we should be ok here.
727 * sysfs_create_shadow_dir - create a shadow directory for an object.
728 * @kobj: object we're creating directory for.
730 * sysfs_make_shadowed_dir must already have been called on this
734 struct dentry *sysfs_create_shadow_dir(struct kobject *kobj)
736 struct dentry *dir = kobj->dentry;
737 struct inode *inode = dir->d_inode;
738 struct dentry *parent = dir->d_parent;
739 struct sysfs_dirent *parent_sd = parent->d_fsdata;
740 struct dentry *shadow;
741 struct sysfs_dirent *sd;
743 shadow = ERR_PTR(-EINVAL);
744 if (!sysfs_is_shadowed_inode(inode))
747 shadow = d_alloc(parent, &dir->d_name);
751 sd = sysfs_new_dirent("_SHADOW_", inode->i_mode, SYSFS_DIR);
754 sd->s_elem.dir.kobj = kobj;
755 /* point to parent_sd but don't attach to it */
756 sd->s_parent = sysfs_get(parent_sd);
757 sysfs_attach_dirent(sd, NULL, shadow);
759 d_instantiate(shadow, igrab(inode));
761 inc_nlink(parent->d_inode);
763 dget(shadow); /* Extra count - pin the dentry in core */
769 shadow = ERR_PTR(-ENOMEM);
774 * sysfs_remove_shadow_dir - remove an object's directory.
775 * @shadow: dentry of shadow directory
777 * The only thing special about this is that we remove any files in
778 * the directory before we remove the directory, and we've inlined
779 * what used to be sysfs_rmdir() below, instead of calling separately.
782 void sysfs_remove_shadow_dir(struct dentry *shadow)
784 __sysfs_remove_dir(shadow);
787 const struct file_operations sysfs_dir_operations = {
788 .open = sysfs_dir_open,
789 .release = sysfs_dir_close,
790 .llseek = sysfs_dir_lseek,
791 .read = generic_read_dir,
792 .readdir = sysfs_readdir,