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 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 void sysfs_attach_dirent(struct sysfs_dirent *sd,
146 struct sysfs_dirent *parent_sd, struct dentry *dentry)
149 sd->s_dentry = dentry;
150 dentry->d_fsdata = sysfs_get(sd);
151 dentry->d_op = &sysfs_dentry_ops;
155 sd->s_parent = sysfs_get(parent_sd);
156 list_add(&sd->s_sibling, &parent_sd->s_children);
162 * Return -EEXIST if there is already a sysfs element with the same name for
165 * called with parent inode's i_mutex held
167 int sysfs_dirent_exist(struct sysfs_dirent *parent_sd,
168 const unsigned char *new)
170 struct sysfs_dirent * sd;
172 list_for_each_entry(sd, &parent_sd->s_children, s_sibling) {
174 if (strcmp(sd->s_name, new))
184 static int init_dir(struct inode * inode)
186 inode->i_op = &sysfs_dir_inode_operations;
187 inode->i_fop = &sysfs_dir_operations;
189 /* directory inodes start off with i_nlink == 2 (for "." entry) */
194 static int init_file(struct inode * inode)
196 inode->i_size = PAGE_SIZE;
197 inode->i_fop = &sysfs_file_operations;
201 static int init_symlink(struct inode * inode)
203 inode->i_op = &sysfs_symlink_inode_operations;
207 static int create_dir(struct kobject *kobj, struct dentry *parent,
208 const char *name, struct dentry **p_dentry)
211 umode_t mode = S_IFDIR| S_IRWXU | S_IRUGO | S_IXUGO;
212 struct dentry *dentry;
213 struct sysfs_dirent *sd;
215 mutex_lock(&parent->d_inode->i_mutex);
217 dentry = lookup_one_len(name, parent, strlen(name));
218 if (IS_ERR(dentry)) {
219 error = PTR_ERR(dentry);
224 if (sysfs_dirent_exist(parent->d_fsdata, name))
228 sd = sysfs_new_dirent(name, mode, SYSFS_DIR);
231 sd->s_elem.dir.kobj = kobj;
232 sysfs_attach_dirent(sd, parent->d_fsdata, dentry);
234 error = sysfs_create(dentry, mode, init_dir);
238 inc_nlink(parent->d_inode);
239 dentry->d_op = &sysfs_dentry_ops;
247 list_del_init(&sd->s_sibling);
254 mutex_unlock(&parent->d_inode->i_mutex);
259 int sysfs_create_subdir(struct kobject * k, const char * n, struct dentry ** d)
261 return create_dir(k,k->dentry,n,d);
265 * sysfs_create_dir - create a directory for an object.
266 * @kobj: object we're creating directory for.
267 * @shadow_parent: parent parent object.
270 int sysfs_create_dir(struct kobject * kobj, struct dentry *shadow_parent)
272 struct dentry * dentry = NULL;
273 struct dentry * parent;
279 parent = shadow_parent;
280 else if (kobj->parent)
281 parent = kobj->parent->dentry;
282 else if (sysfs_mount && sysfs_mount->mnt_sb)
283 parent = sysfs_mount->mnt_sb->s_root;
287 error = create_dir(kobj,parent,kobject_name(kobj),&dentry);
289 kobj->dentry = dentry;
293 /* attaches attribute's sysfs_dirent to the dentry corresponding to the
296 static int sysfs_attach_attr(struct sysfs_dirent * sd, struct dentry * dentry)
298 struct attribute * attr = NULL;
299 struct bin_attribute * bin_attr = NULL;
300 int (* init) (struct inode *) = NULL;
303 if (sd->s_type & SYSFS_KOBJ_BIN_ATTR) {
304 bin_attr = sd->s_elem.bin_attr.bin_attr;
305 attr = &bin_attr->attr;
307 attr = sd->s_elem.attr.attr;
311 dentry->d_fsdata = sysfs_get(sd);
312 /* protect sd->s_dentry against sysfs_d_iput */
313 spin_lock(&sysfs_lock);
314 sd->s_dentry = dentry;
315 spin_unlock(&sysfs_lock);
316 error = sysfs_create(dentry, (attr->mode & S_IALLUGO) | S_IFREG, init);
323 dentry->d_inode->i_size = bin_attr->size;
324 dentry->d_inode->i_fop = &bin_fops;
326 dentry->d_op = &sysfs_dentry_ops;
332 static int sysfs_attach_link(struct sysfs_dirent * sd, struct dentry * dentry)
336 dentry->d_fsdata = sysfs_get(sd);
337 /* protect sd->s_dentry against sysfs_d_iput */
338 spin_lock(&sysfs_lock);
339 sd->s_dentry = dentry;
340 spin_unlock(&sysfs_lock);
341 err = sysfs_create(dentry, S_IFLNK|S_IRWXUGO, init_symlink);
343 dentry->d_op = &sysfs_dentry_ops;
351 static struct dentry * sysfs_lookup(struct inode *dir, struct dentry *dentry,
352 struct nameidata *nd)
354 struct sysfs_dirent * parent_sd = dentry->d_parent->d_fsdata;
355 struct sysfs_dirent * sd;
358 list_for_each_entry(sd, &parent_sd->s_children, s_sibling) {
359 if (sd->s_type & SYSFS_NOT_PINNED) {
360 if (strcmp(sd->s_name, dentry->d_name.name))
363 if (sd->s_type & SYSFS_KOBJ_LINK)
364 err = sysfs_attach_link(sd, dentry);
366 err = sysfs_attach_attr(sd, dentry);
374 const struct inode_operations sysfs_dir_inode_operations = {
375 .lookup = sysfs_lookup,
376 .setattr = sysfs_setattr,
379 static void remove_dir(struct dentry * d)
381 struct dentry * parent = dget(d->d_parent);
382 struct sysfs_dirent * sd;
384 mutex_lock(&parent->d_inode->i_mutex);
387 list_del_init(&sd->s_sibling);
389 simple_rmdir(parent->d_inode,d);
391 pr_debug(" o %s removing done (%d)\n",d->d_name.name,
392 atomic_read(&d->d_count));
394 mutex_unlock(&parent->d_inode->i_mutex);
397 sysfs_deactivate(sd);
401 void sysfs_remove_subdir(struct dentry * d)
407 static void __sysfs_remove_dir(struct dentry *dentry)
410 struct sysfs_dirent * parent_sd;
411 struct sysfs_dirent * sd, * tmp;
417 pr_debug("sysfs %s: removing dir\n",dentry->d_name.name);
418 mutex_lock(&dentry->d_inode->i_mutex);
419 parent_sd = dentry->d_fsdata;
420 list_for_each_entry_safe(sd, tmp, &parent_sd->s_children, s_sibling) {
421 if (!sd->s_type || !(sd->s_type & SYSFS_NOT_PINNED))
423 list_move(&sd->s_sibling, &removed);
424 sysfs_drop_dentry(sd, dentry);
426 mutex_unlock(&dentry->d_inode->i_mutex);
428 list_for_each_entry_safe(sd, tmp, &removed, s_sibling) {
429 list_del_init(&sd->s_sibling);
430 sysfs_deactivate(sd);
436 * Drop reference from dget() on entrance.
442 * sysfs_remove_dir - remove an object's directory.
445 * The only thing special about this is that we remove any files in
446 * the directory before we remove the directory, and we've inlined
447 * what used to be sysfs_rmdir() below, instead of calling separately.
450 void sysfs_remove_dir(struct kobject * kobj)
452 struct dentry *d = kobj->dentry;
454 spin_lock(&kobj_sysfs_assoc_lock);
456 spin_unlock(&kobj_sysfs_assoc_lock);
458 __sysfs_remove_dir(d);
461 int sysfs_rename_dir(struct kobject * kobj, struct dentry *new_parent,
462 const char *new_name)
464 struct sysfs_dirent *sd = kobj->dentry->d_fsdata;
465 struct sysfs_dirent *parent_sd = new_parent->d_fsdata;
466 struct dentry *new_dentry;
473 down_write(&sysfs_rename_sem);
474 mutex_lock(&new_parent->d_inode->i_mutex);
476 new_dentry = lookup_one_len(new_name, new_parent, strlen(new_name));
477 if (IS_ERR(new_dentry)) {
478 error = PTR_ERR(new_dentry);
482 /* By allowing two different directories with the same
483 * d_parent we allow this routine to move between different
484 * shadows of the same directory
487 if (kobj->dentry->d_parent->d_inode != new_parent->d_inode ||
488 new_dentry->d_parent->d_inode != new_parent->d_inode ||
489 new_dentry == kobj->dentry)
493 if (new_dentry->d_inode)
496 /* rename kobject and sysfs_dirent */
498 new_name = dup_name = kstrdup(new_name, GFP_KERNEL);
502 error = kobject_set_name(kobj, "%s", new_name);
507 sd->s_name = new_name;
509 /* move under the new parent */
510 d_add(new_dentry, NULL);
511 d_move(kobj->dentry, new_dentry);
513 list_del_init(&sd->s_sibling);
514 list_add(&sd->s_sibling, &parent_sd->s_children);
526 mutex_unlock(&new_parent->d_inode->i_mutex);
527 up_write(&sysfs_rename_sem);
531 int sysfs_move_dir(struct kobject *kobj, struct kobject *new_parent)
533 struct dentry *old_parent_dentry, *new_parent_dentry, *new_dentry;
534 struct sysfs_dirent *new_parent_sd, *sd;
537 old_parent_dentry = kobj->parent ?
538 kobj->parent->dentry : sysfs_mount->mnt_sb->s_root;
539 new_parent_dentry = new_parent ?
540 new_parent->dentry : sysfs_mount->mnt_sb->s_root;
542 if (old_parent_dentry->d_inode == new_parent_dentry->d_inode)
543 return 0; /* nothing to move */
545 mutex_lock(&old_parent_dentry->d_inode->i_mutex);
546 if (!mutex_trylock(&new_parent_dentry->d_inode->i_mutex)) {
547 mutex_unlock(&old_parent_dentry->d_inode->i_mutex);
551 new_parent_sd = new_parent_dentry->d_fsdata;
552 sd = kobj->dentry->d_fsdata;
554 new_dentry = lookup_one_len(kobj->name, new_parent_dentry,
556 if (IS_ERR(new_dentry)) {
557 error = PTR_ERR(new_dentry);
561 d_add(new_dentry, NULL);
562 d_move(kobj->dentry, new_dentry);
565 /* Remove from old parent's list and insert into new parent's list. */
566 list_del_init(&sd->s_sibling);
567 list_add(&sd->s_sibling, &new_parent_sd->s_children);
570 mutex_unlock(&new_parent_dentry->d_inode->i_mutex);
571 mutex_unlock(&old_parent_dentry->d_inode->i_mutex);
576 static int sysfs_dir_open(struct inode *inode, struct file *file)
578 struct dentry * dentry = file->f_path.dentry;
579 struct sysfs_dirent * parent_sd = dentry->d_fsdata;
580 struct sysfs_dirent * sd;
582 mutex_lock(&dentry->d_inode->i_mutex);
583 sd = sysfs_new_dirent("_DIR_", 0, 0);
585 sysfs_attach_dirent(sd, parent_sd, NULL);
586 mutex_unlock(&dentry->d_inode->i_mutex);
588 file->private_data = sd;
589 return sd ? 0 : -ENOMEM;
592 static int sysfs_dir_close(struct inode *inode, struct file *file)
594 struct dentry * dentry = file->f_path.dentry;
595 struct sysfs_dirent * cursor = file->private_data;
597 mutex_lock(&dentry->d_inode->i_mutex);
598 list_del_init(&cursor->s_sibling);
599 mutex_unlock(&dentry->d_inode->i_mutex);
601 release_sysfs_dirent(cursor);
606 /* Relationship between s_mode and the DT_xxx types */
607 static inline unsigned char dt_type(struct sysfs_dirent *sd)
609 return (sd->s_mode >> 12) & 15;
612 static int sysfs_readdir(struct file * filp, void * dirent, filldir_t filldir)
614 struct dentry *dentry = filp->f_path.dentry;
615 struct sysfs_dirent * parent_sd = dentry->d_fsdata;
616 struct sysfs_dirent *cursor = filp->private_data;
617 struct list_head *p, *q = &cursor->s_sibling;
623 ino = parent_sd->s_ino;
624 if (filldir(dirent, ".", 1, i, ino, DT_DIR) < 0)
630 if (parent_sd->s_parent)
631 ino = parent_sd->s_parent->s_ino;
633 ino = parent_sd->s_ino;
634 if (filldir(dirent, "..", 2, i, ino, DT_DIR) < 0)
640 if (filp->f_pos == 2)
641 list_move(q, &parent_sd->s_children);
643 for (p=q->next; p!= &parent_sd->s_children; p=p->next) {
644 struct sysfs_dirent *next;
648 next = list_entry(p, struct sysfs_dirent,
657 if (filldir(dirent, name, len, filp->f_pos, ino,
669 static loff_t sysfs_dir_lseek(struct file * file, loff_t offset, int origin)
671 struct dentry * dentry = file->f_path.dentry;
673 mutex_lock(&dentry->d_inode->i_mutex);
676 offset += file->f_pos;
681 mutex_unlock(&file->f_path.dentry->d_inode->i_mutex);
684 if (offset != file->f_pos) {
685 file->f_pos = offset;
686 if (file->f_pos >= 2) {
687 struct sysfs_dirent *sd = dentry->d_fsdata;
688 struct sysfs_dirent *cursor = file->private_data;
690 loff_t n = file->f_pos - 2;
692 list_del(&cursor->s_sibling);
693 p = sd->s_children.next;
694 while (n && p != &sd->s_children) {
695 struct sysfs_dirent *next;
696 next = list_entry(p, struct sysfs_dirent,
702 list_add_tail(&cursor->s_sibling, p);
705 mutex_unlock(&dentry->d_inode->i_mutex);
711 * sysfs_make_shadowed_dir - Setup so a directory can be shadowed
712 * @kobj: object we're creating shadow of.
715 int sysfs_make_shadowed_dir(struct kobject *kobj,
716 void * (*follow_link)(struct dentry *, struct nameidata *))
719 struct inode_operations *i_op;
721 inode = kobj->dentry->d_inode;
722 if (inode->i_op != &sysfs_dir_inode_operations)
725 i_op = kmalloc(sizeof(*i_op), GFP_KERNEL);
729 memcpy(i_op, &sysfs_dir_inode_operations, sizeof(*i_op));
730 i_op->follow_link = follow_link;
732 /* Locking of inode->i_op?
733 * Since setting i_op is a single word write and they
734 * are atomic we should be ok here.
741 * sysfs_create_shadow_dir - create a shadow directory for an object.
742 * @kobj: object we're creating directory for.
744 * sysfs_make_shadowed_dir must already have been called on this
748 struct dentry *sysfs_create_shadow_dir(struct kobject *kobj)
750 struct dentry *dir = kobj->dentry;
751 struct inode *inode = dir->d_inode;
752 struct dentry *parent = dir->d_parent;
753 struct sysfs_dirent *parent_sd = parent->d_fsdata;
754 struct dentry *shadow;
755 struct sysfs_dirent *sd;
757 shadow = ERR_PTR(-EINVAL);
758 if (!sysfs_is_shadowed_inode(inode))
761 shadow = d_alloc(parent, &dir->d_name);
765 sd = sysfs_new_dirent("_SHADOW_", inode->i_mode, SYSFS_DIR);
768 sd->s_elem.dir.kobj = kobj;
769 /* point to parent_sd but don't attach to it */
770 sd->s_parent = sysfs_get(parent_sd);
771 sysfs_attach_dirent(sd, NULL, shadow);
773 d_instantiate(shadow, igrab(inode));
775 inc_nlink(parent->d_inode);
776 shadow->d_op = &sysfs_dentry_ops;
778 dget(shadow); /* Extra count - pin the dentry in core */
784 shadow = ERR_PTR(-ENOMEM);
789 * sysfs_remove_shadow_dir - remove an object's directory.
790 * @shadow: dentry of shadow directory
792 * The only thing special about this is that we remove any files in
793 * the directory before we remove the directory, and we've inlined
794 * what used to be sysfs_rmdir() below, instead of calling separately.
797 void sysfs_remove_shadow_dir(struct dentry *shadow)
799 __sysfs_remove_dir(shadow);
802 const struct file_operations sysfs_dir_operations = {
803 .open = sysfs_dir_open,
804 .release = sysfs_dir_close,
805 .llseek = sysfs_dir_lseek,
806 .read = generic_read_dir,
807 .readdir = sysfs_readdir,