2 * fs/sysfs/dir.c - sysfs core and dir operation implementation
4 * Copyright (c) 2001-3 Patrick Mochel
5 * Copyright (c) 2007 SUSE Linux Products GmbH
6 * Copyright (c) 2007 Tejun Heo <teheo@suse.de>
8 * This file is released under the GPLv2.
10 * Please see Documentation/filesystems/sysfs.txt for more information.
16 #include <linux/mount.h>
17 #include <linux/module.h>
18 #include <linux/kobject.h>
19 #include <linux/namei.h>
20 #include <linux/idr.h>
21 #include <linux/completion.h>
22 #include <linux/mutex.h>
23 #include <linux/slab.h>
24 #include <linux/security.h>
27 DEFINE_MUTEX(sysfs_mutex
);
28 DEFINE_MUTEX(sysfs_rename_mutex
);
29 DEFINE_SPINLOCK(sysfs_assoc_lock
);
31 static DEFINE_SPINLOCK(sysfs_ino_lock
);
32 static DEFINE_IDA(sysfs_ino_ida
);
35 * sysfs_link_sibling - link sysfs_dirent into sibling list
36 * @sd: sysfs_dirent of interest
38 * Link @sd into its sibling list which starts from
39 * sd->s_parent->s_dir.children.
42 * mutex_lock(sysfs_mutex)
44 static void sysfs_link_sibling(struct sysfs_dirent
*sd
)
46 struct sysfs_dirent
*parent_sd
= sd
->s_parent
;
47 struct sysfs_dirent
**pos
;
49 BUG_ON(sd
->s_sibling
);
51 /* Store directory entries in order by ino. This allows
52 * readdir to properly restart without having to add a
53 * cursor into the s_dir.children list.
55 for (pos
= &parent_sd
->s_dir
.children
; *pos
; pos
= &(*pos
)->s_sibling
) {
56 if (sd
->s_ino
< (*pos
)->s_ino
)
64 * sysfs_unlink_sibling - unlink sysfs_dirent from sibling list
65 * @sd: sysfs_dirent of interest
67 * Unlink @sd from its sibling list which starts from
68 * sd->s_parent->s_dir.children.
71 * mutex_lock(sysfs_mutex)
73 static void sysfs_unlink_sibling(struct sysfs_dirent
*sd
)
75 struct sysfs_dirent
**pos
;
77 for (pos
= &sd
->s_parent
->s_dir
.children
; *pos
;
78 pos
= &(*pos
)->s_sibling
) {
88 * sysfs_get_dentry - get dentry for the given sysfs_dirent
89 * @sd: sysfs_dirent of interest
91 * Get dentry for @sd. Dentry is looked up if currently not
92 * present. This function descends from the root looking up
93 * dentry for each step.
96 * mutex_lock(sysfs_rename_mutex)
99 * Pointer to found dentry on success, ERR_PTR() value on error.
101 struct dentry
*sysfs_get_dentry(struct sysfs_dirent
*sd
)
103 struct dentry
*dentry
= dget(sysfs_sb
->s_root
);
105 while (dentry
->d_fsdata
!= sd
) {
106 struct sysfs_dirent
*cur
;
107 struct dentry
*parent
;
109 /* find the first ancestor which hasn't been looked up */
111 while (cur
->s_parent
!= dentry
->d_fsdata
)
116 mutex_lock(&parent
->d_inode
->i_mutex
);
117 dentry
= lookup_one_noperm(cur
->s_name
, parent
);
118 mutex_unlock(&parent
->d_inode
->i_mutex
);
128 * sysfs_get_active - get an active reference to sysfs_dirent
129 * @sd: sysfs_dirent to get an active reference to
131 * Get an active reference of @sd. This function is noop if @sd
135 * Pointer to @sd on success, NULL on failure.
137 static struct sysfs_dirent
*sysfs_get_active(struct sysfs_dirent
*sd
)
145 v
= atomic_read(&sd
->s_active
);
149 t
= atomic_cmpxchg(&sd
->s_active
, v
, v
+ 1);
160 * sysfs_put_active - put an active reference to sysfs_dirent
161 * @sd: sysfs_dirent to put an active reference to
163 * Put an active reference to @sd. This function is noop if @sd
166 static void sysfs_put_active(struct sysfs_dirent
*sd
)
168 struct completion
*cmpl
;
174 v
= atomic_dec_return(&sd
->s_active
);
175 if (likely(v
!= SD_DEACTIVATED_BIAS
))
178 /* atomic_dec_return() is a mb(), we'll always see the updated
181 cmpl
= (void *)sd
->s_sibling
;
186 * sysfs_get_active_two - get active references to sysfs_dirent and parent
187 * @sd: sysfs_dirent of interest
189 * Get active reference to @sd and its parent. Parent's active
190 * reference is grabbed first. This function is noop if @sd is
194 * Pointer to @sd on success, NULL on failure.
196 struct sysfs_dirent
*sysfs_get_active_two(struct sysfs_dirent
*sd
)
199 if (sd
->s_parent
&& unlikely(!sysfs_get_active(sd
->s_parent
)))
201 if (unlikely(!sysfs_get_active(sd
))) {
202 sysfs_put_active(sd
->s_parent
);
210 * sysfs_put_active_two - put active references to sysfs_dirent and parent
211 * @sd: sysfs_dirent of interest
213 * Put active references to @sd and its parent. This function is
214 * noop if @sd is NULL.
216 void sysfs_put_active_two(struct sysfs_dirent
*sd
)
219 sysfs_put_active(sd
);
220 sysfs_put_active(sd
->s_parent
);
225 * sysfs_deactivate - deactivate sysfs_dirent
226 * @sd: sysfs_dirent to deactivate
228 * Deny new active references and drain existing ones.
230 static void sysfs_deactivate(struct sysfs_dirent
*sd
)
232 DECLARE_COMPLETION_ONSTACK(wait
);
235 BUG_ON(sd
->s_sibling
|| !(sd
->s_flags
& SYSFS_FLAG_REMOVED
));
236 sd
->s_sibling
= (void *)&wait
;
238 /* atomic_add_return() is a mb(), put_active() will always see
239 * the updated sd->s_sibling.
241 v
= atomic_add_return(SD_DEACTIVATED_BIAS
, &sd
->s_active
);
243 if (v
!= SD_DEACTIVATED_BIAS
)
244 wait_for_completion(&wait
);
246 sd
->s_sibling
= NULL
;
249 static int sysfs_alloc_ino(ino_t
*pino
)
254 spin_lock(&sysfs_ino_lock
);
255 rc
= ida_get_new_above(&sysfs_ino_ida
, 2, &ino
);
256 spin_unlock(&sysfs_ino_lock
);
259 if (ida_pre_get(&sysfs_ino_ida
, GFP_KERNEL
))
268 static void sysfs_free_ino(ino_t ino
)
270 spin_lock(&sysfs_ino_lock
);
271 ida_remove(&sysfs_ino_ida
, ino
);
272 spin_unlock(&sysfs_ino_lock
);
275 void release_sysfs_dirent(struct sysfs_dirent
* sd
)
277 struct sysfs_dirent
*parent_sd
;
280 /* Moving/renaming is always done while holding reference.
281 * sd->s_parent won't change beneath us.
283 parent_sd
= sd
->s_parent
;
285 if (sysfs_type(sd
) == SYSFS_KOBJ_LINK
)
286 sysfs_put(sd
->s_symlink
.target_sd
);
287 if (sysfs_type(sd
) & SYSFS_COPY_NAME
)
289 if (sd
->s_iattr
&& sd
->s_iattr
->ia_secdata
)
290 security_release_secctx(sd
->s_iattr
->ia_secdata
,
291 sd
->s_iattr
->ia_secdata_len
);
293 sysfs_free_ino(sd
->s_ino
);
294 kmem_cache_free(sysfs_dir_cachep
, sd
);
297 if (sd
&& atomic_dec_and_test(&sd
->s_count
))
301 static int sysfs_dentry_delete(struct dentry
*dentry
)
303 struct sysfs_dirent
*sd
= dentry
->d_fsdata
;
304 return !!(sd
->s_flags
& SYSFS_FLAG_REMOVED
);
307 static int sysfs_dentry_revalidate(struct dentry
*dentry
, struct nameidata
*nd
)
309 struct sysfs_dirent
*sd
= dentry
->d_fsdata
;
312 mutex_lock(&sysfs_mutex
);
314 /* The sysfs dirent has been deleted */
315 if (sd
->s_flags
& SYSFS_FLAG_REMOVED
)
318 mutex_unlock(&sysfs_mutex
);
322 /* Remove the dentry from the dcache hashes.
323 * If this is a deleted dentry we use d_drop instead of d_delete
324 * so sysfs doesn't need to cope with negative dentries.
326 is_dir
= (sysfs_type(sd
) == SYSFS_DIR
);
327 mutex_unlock(&sysfs_mutex
);
329 /* If we have submounts we must allow the vfs caches
330 * to lie about the state of the filesystem to prevent
331 * leaks and other nasty things.
333 if (have_submounts(dentry
))
335 shrink_dcache_parent(dentry
);
341 static void sysfs_dentry_iput(struct dentry
*dentry
, struct inode
*inode
)
343 struct sysfs_dirent
* sd
= dentry
->d_fsdata
;
349 static const struct dentry_operations sysfs_dentry_ops
= {
350 .d_revalidate
= sysfs_dentry_revalidate
,
351 .d_delete
= sysfs_dentry_delete
,
352 .d_iput
= sysfs_dentry_iput
,
355 struct sysfs_dirent
*sysfs_new_dirent(const char *name
, umode_t mode
, int type
)
357 char *dup_name
= NULL
;
358 struct sysfs_dirent
*sd
;
360 if (type
& SYSFS_COPY_NAME
) {
361 name
= dup_name
= kstrdup(name
, GFP_KERNEL
);
366 sd
= kmem_cache_zalloc(sysfs_dir_cachep
, GFP_KERNEL
);
370 if (sysfs_alloc_ino(&sd
->s_ino
))
373 atomic_set(&sd
->s_count
, 1);
374 atomic_set(&sd
->s_active
, 0);
383 kmem_cache_free(sysfs_dir_cachep
, sd
);
389 static int sysfs_ilookup_test(struct inode
*inode
, void *arg
)
391 struct sysfs_dirent
*sd
= arg
;
392 return inode
->i_ino
== sd
->s_ino
;
396 * sysfs_addrm_start - prepare for sysfs_dirent add/remove
397 * @acxt: pointer to sysfs_addrm_cxt to be used
398 * @parent_sd: parent sysfs_dirent
400 * This function is called when the caller is about to add or
401 * remove sysfs_dirent under @parent_sd. This function acquires
402 * sysfs_mutex, grabs inode for @parent_sd if available and lock
403 * i_mutex of it. @acxt is used to keep and pass context to
404 * other addrm functions.
407 * Kernel thread context (may sleep). sysfs_mutex is locked on
408 * return. i_mutex of parent inode is locked on return if
411 void sysfs_addrm_start(struct sysfs_addrm_cxt
*acxt
,
412 struct sysfs_dirent
*parent_sd
)
416 memset(acxt
, 0, sizeof(*acxt
));
417 acxt
->parent_sd
= parent_sd
;
419 /* Lookup parent inode. inode initialization is protected by
420 * sysfs_mutex, so inode existence can be determined by
421 * looking up inode while holding sysfs_mutex.
423 mutex_lock(&sysfs_mutex
);
425 inode
= ilookup5(sysfs_sb
, parent_sd
->s_ino
, sysfs_ilookup_test
,
428 WARN_ON(inode
->i_state
& I_NEW
);
430 /* parent inode available */
431 acxt
->parent_inode
= inode
;
433 /* sysfs_mutex is below i_mutex in lock hierarchy.
434 * First, trylock i_mutex. If fails, unlock
435 * sysfs_mutex and lock them in order.
437 if (!mutex_trylock(&inode
->i_mutex
)) {
438 mutex_unlock(&sysfs_mutex
);
439 mutex_lock(&inode
->i_mutex
);
440 mutex_lock(&sysfs_mutex
);
446 * __sysfs_add_one - add sysfs_dirent to parent without warning
447 * @acxt: addrm context to use
448 * @sd: sysfs_dirent to be added
450 * Get @acxt->parent_sd and set sd->s_parent to it and increment
451 * nlink of parent inode if @sd is a directory and link into the
452 * children list of the parent.
454 * This function should be called between calls to
455 * sysfs_addrm_start() and sysfs_addrm_finish() and should be
456 * passed the same @acxt as passed to sysfs_addrm_start().
459 * Determined by sysfs_addrm_start().
462 * 0 on success, -EEXIST if entry with the given name already
465 int __sysfs_add_one(struct sysfs_addrm_cxt
*acxt
, struct sysfs_dirent
*sd
)
467 if (sysfs_find_dirent(acxt
->parent_sd
, sd
->s_name
))
470 sd
->s_parent
= sysfs_get(acxt
->parent_sd
);
472 if (sysfs_type(sd
) == SYSFS_DIR
&& acxt
->parent_inode
)
473 inc_nlink(acxt
->parent_inode
);
477 sysfs_link_sibling(sd
);
483 * sysfs_pathname - return full path to sysfs dirent
484 * @sd: sysfs_dirent whose path we want
485 * @path: caller allocated buffer
487 * Gives the name "/" to the sysfs_root entry; any path returned
488 * is relative to wherever sysfs is mounted.
490 * XXX: does no error checking on @path size
492 static char *sysfs_pathname(struct sysfs_dirent
*sd
, char *path
)
495 sysfs_pathname(sd
->s_parent
, path
);
498 strcat(path
, sd
->s_name
);
503 * sysfs_add_one - add sysfs_dirent to parent
504 * @acxt: addrm context to use
505 * @sd: sysfs_dirent to be added
507 * Get @acxt->parent_sd and set sd->s_parent to it and increment
508 * nlink of parent inode if @sd is a directory and link into the
509 * children list of the parent.
511 * This function should be called between calls to
512 * sysfs_addrm_start() and sysfs_addrm_finish() and should be
513 * passed the same @acxt as passed to sysfs_addrm_start().
516 * Determined by sysfs_addrm_start().
519 * 0 on success, -EEXIST if entry with the given name already
522 int sysfs_add_one(struct sysfs_addrm_cxt
*acxt
, struct sysfs_dirent
*sd
)
526 ret
= __sysfs_add_one(acxt
, sd
);
527 if (ret
== -EEXIST
) {
528 char *path
= kzalloc(PATH_MAX
, GFP_KERNEL
);
530 "sysfs: cannot create duplicate filename '%s'\n",
531 (path
== NULL
) ? sd
->s_name
:
532 strcat(strcat(sysfs_pathname(acxt
->parent_sd
, path
), "/"),
541 * sysfs_remove_one - remove sysfs_dirent from parent
542 * @acxt: addrm context to use
543 * @sd: sysfs_dirent to be removed
545 * Mark @sd removed and drop nlink of parent inode if @sd is a
546 * directory. @sd is unlinked from the children list.
548 * This function should be called between calls to
549 * sysfs_addrm_start() and sysfs_addrm_finish() and should be
550 * passed the same @acxt as passed to sysfs_addrm_start().
553 * Determined by sysfs_addrm_start().
555 void sysfs_remove_one(struct sysfs_addrm_cxt
*acxt
, struct sysfs_dirent
*sd
)
557 BUG_ON(sd
->s_flags
& SYSFS_FLAG_REMOVED
);
559 sysfs_unlink_sibling(sd
);
561 sd
->s_flags
|= SYSFS_FLAG_REMOVED
;
562 sd
->s_sibling
= acxt
->removed
;
565 if (sysfs_type(sd
) == SYSFS_DIR
&& acxt
->parent_inode
)
566 drop_nlink(acxt
->parent_inode
);
572 * sysfs_dec_nlink - Decrement link count for the specified sysfs_dirent
573 * @sd: target sysfs_dirent
575 * Decrement nlink for @sd. @sd must have been unlinked from its
576 * parent on entry to this function such that it can't be looked
579 static void sysfs_dec_nlink(struct sysfs_dirent
*sd
)
583 inode
= ilookup(sysfs_sb
, sd
->s_ino
);
587 /* adjust nlink and update timestamp */
588 mutex_lock(&inode
->i_mutex
);
590 inode
->i_ctime
= CURRENT_TIME
;
592 if (sysfs_type(sd
) == SYSFS_DIR
)
595 mutex_unlock(&inode
->i_mutex
);
601 * sysfs_addrm_finish - finish up sysfs_dirent add/remove
602 * @acxt: addrm context to finish up
604 * Finish up sysfs_dirent add/remove. Resources acquired by
605 * sysfs_addrm_start() are released and removed sysfs_dirents are
606 * cleaned up. Timestamps on the parent inode are updated.
609 * All mutexes acquired by sysfs_addrm_start() are released.
611 void sysfs_addrm_finish(struct sysfs_addrm_cxt
*acxt
)
613 /* release resources acquired by sysfs_addrm_start() */
614 mutex_unlock(&sysfs_mutex
);
615 if (acxt
->parent_inode
) {
616 struct inode
*inode
= acxt
->parent_inode
;
618 /* if added/removed, update timestamps on the parent */
620 inode
->i_ctime
= inode
->i_mtime
= CURRENT_TIME
;
622 mutex_unlock(&inode
->i_mutex
);
626 /* kill removed sysfs_dirents */
627 while (acxt
->removed
) {
628 struct sysfs_dirent
*sd
= acxt
->removed
;
630 acxt
->removed
= sd
->s_sibling
;
631 sd
->s_sibling
= NULL
;
634 sysfs_deactivate(sd
);
641 * sysfs_find_dirent - find sysfs_dirent with the given name
642 * @parent_sd: sysfs_dirent to search under
643 * @name: name to look for
645 * Look for sysfs_dirent with name @name under @parent_sd.
648 * mutex_lock(sysfs_mutex)
651 * Pointer to sysfs_dirent if found, NULL if not.
653 struct sysfs_dirent
*sysfs_find_dirent(struct sysfs_dirent
*parent_sd
,
654 const unsigned char *name
)
656 struct sysfs_dirent
*sd
;
658 for (sd
= parent_sd
->s_dir
.children
; sd
; sd
= sd
->s_sibling
)
659 if (!strcmp(sd
->s_name
, name
))
665 * sysfs_get_dirent - find and get sysfs_dirent with the given name
666 * @parent_sd: sysfs_dirent to search under
667 * @name: name to look for
669 * Look for sysfs_dirent with name @name under @parent_sd and get
673 * Kernel thread context (may sleep). Grabs sysfs_mutex.
676 * Pointer to sysfs_dirent if found, NULL if not.
678 struct sysfs_dirent
*sysfs_get_dirent(struct sysfs_dirent
*parent_sd
,
679 const unsigned char *name
)
681 struct sysfs_dirent
*sd
;
683 mutex_lock(&sysfs_mutex
);
684 sd
= sysfs_find_dirent(parent_sd
, name
);
686 mutex_unlock(&sysfs_mutex
);
690 EXPORT_SYMBOL_GPL(sysfs_get_dirent
);
692 static int create_dir(struct kobject
*kobj
, struct sysfs_dirent
*parent_sd
,
693 const char *name
, struct sysfs_dirent
**p_sd
)
695 umode_t mode
= S_IFDIR
| S_IRWXU
| S_IRUGO
| S_IXUGO
;
696 struct sysfs_addrm_cxt acxt
;
697 struct sysfs_dirent
*sd
;
701 sd
= sysfs_new_dirent(name
, mode
, SYSFS_DIR
);
704 sd
->s_dir
.kobj
= kobj
;
707 sysfs_addrm_start(&acxt
, parent_sd
);
708 rc
= sysfs_add_one(&acxt
, sd
);
709 sysfs_addrm_finish(&acxt
);
719 int sysfs_create_subdir(struct kobject
*kobj
, const char *name
,
720 struct sysfs_dirent
**p_sd
)
722 return create_dir(kobj
, kobj
->sd
, name
, p_sd
);
726 * sysfs_create_dir - create a directory for an object.
727 * @kobj: object we're creating directory for.
729 int sysfs_create_dir(struct kobject
* kobj
)
731 struct sysfs_dirent
*parent_sd
, *sd
;
737 parent_sd
= kobj
->parent
->sd
;
739 parent_sd
= &sysfs_root
;
741 error
= create_dir(kobj
, parent_sd
, kobject_name(kobj
), &sd
);
747 static struct dentry
* sysfs_lookup(struct inode
*dir
, struct dentry
*dentry
,
748 struct nameidata
*nd
)
750 struct dentry
*ret
= NULL
;
751 struct sysfs_dirent
*parent_sd
= dentry
->d_parent
->d_fsdata
;
752 struct sysfs_dirent
*sd
;
755 mutex_lock(&sysfs_mutex
);
757 sd
= sysfs_find_dirent(parent_sd
, dentry
->d_name
.name
);
761 ret
= ERR_PTR(-ENOENT
);
765 /* attach dentry and inode */
766 inode
= sysfs_get_inode(sd
);
768 ret
= ERR_PTR(-ENOMEM
);
772 /* instantiate and hash dentry */
773 dentry
->d_op
= &sysfs_dentry_ops
;
774 dentry
->d_fsdata
= sysfs_get(sd
);
775 d_instantiate(dentry
, inode
);
779 mutex_unlock(&sysfs_mutex
);
783 const struct inode_operations sysfs_dir_inode_operations
= {
784 .lookup
= sysfs_lookup
,
785 .setattr
= sysfs_setattr
,
786 .setxattr
= sysfs_setxattr
,
789 static void remove_dir(struct sysfs_dirent
*sd
)
791 struct sysfs_addrm_cxt acxt
;
793 sysfs_addrm_start(&acxt
, sd
->s_parent
);
794 sysfs_remove_one(&acxt
, sd
);
795 sysfs_addrm_finish(&acxt
);
798 void sysfs_remove_subdir(struct sysfs_dirent
*sd
)
804 static void __sysfs_remove_dir(struct sysfs_dirent
*dir_sd
)
806 struct sysfs_addrm_cxt acxt
;
807 struct sysfs_dirent
**pos
;
812 pr_debug("sysfs %s: removing dir\n", dir_sd
->s_name
);
813 sysfs_addrm_start(&acxt
, dir_sd
);
814 pos
= &dir_sd
->s_dir
.children
;
816 struct sysfs_dirent
*sd
= *pos
;
818 if (sysfs_type(sd
) != SYSFS_DIR
)
819 sysfs_remove_one(&acxt
, sd
);
821 pos
= &(*pos
)->s_sibling
;
823 sysfs_addrm_finish(&acxt
);
829 * sysfs_remove_dir - remove an object's directory.
832 * The only thing special about this is that we remove any files in
833 * the directory before we remove the directory, and we've inlined
834 * what used to be sysfs_rmdir() below, instead of calling separately.
837 void sysfs_remove_dir(struct kobject
* kobj
)
839 struct sysfs_dirent
*sd
= kobj
->sd
;
841 spin_lock(&sysfs_assoc_lock
);
843 spin_unlock(&sysfs_assoc_lock
);
845 __sysfs_remove_dir(sd
);
848 int sysfs_rename_dir(struct kobject
* kobj
, const char *new_name
)
850 struct sysfs_dirent
*sd
= kobj
->sd
;
851 struct dentry
*parent
= NULL
;
852 struct dentry
*old_dentry
= NULL
, *new_dentry
= NULL
;
853 const char *dup_name
= NULL
;
856 mutex_lock(&sysfs_rename_mutex
);
859 if (strcmp(sd
->s_name
, new_name
) == 0)
860 goto out
; /* nothing to rename */
862 /* get the original dentry */
863 old_dentry
= sysfs_get_dentry(sd
);
864 if (IS_ERR(old_dentry
)) {
865 error
= PTR_ERR(old_dentry
);
870 parent
= old_dentry
->d_parent
;
872 /* lock parent and get dentry for new name */
873 mutex_lock(&parent
->d_inode
->i_mutex
);
874 mutex_lock(&sysfs_mutex
);
877 if (sysfs_find_dirent(sd
->s_parent
, new_name
))
881 new_dentry
= d_alloc_name(parent
, new_name
);
885 /* rename sysfs_dirent */
887 new_name
= dup_name
= kstrdup(new_name
, GFP_KERNEL
);
891 dup_name
= sd
->s_name
;
892 sd
->s_name
= new_name
;
895 d_add(new_dentry
, NULL
);
896 d_move(old_dentry
, new_dentry
);
900 mutex_unlock(&sysfs_mutex
);
901 mutex_unlock(&parent
->d_inode
->i_mutex
);
906 mutex_unlock(&sysfs_rename_mutex
);
910 int sysfs_move_dir(struct kobject
*kobj
, struct kobject
*new_parent_kobj
)
912 struct sysfs_dirent
*sd
= kobj
->sd
;
913 struct sysfs_dirent
*new_parent_sd
;
914 struct dentry
*old_parent
, *new_parent
= NULL
;
915 struct dentry
*old_dentry
= NULL
, *new_dentry
= NULL
;
918 mutex_lock(&sysfs_rename_mutex
);
919 BUG_ON(!sd
->s_parent
);
920 new_parent_sd
= (new_parent_kobj
&& new_parent_kobj
->sd
) ?
921 new_parent_kobj
->sd
: &sysfs_root
;
924 if (sd
->s_parent
== new_parent_sd
)
925 goto out
; /* nothing to move */
928 old_dentry
= sysfs_get_dentry(sd
);
929 if (IS_ERR(old_dentry
)) {
930 error
= PTR_ERR(old_dentry
);
934 old_parent
= old_dentry
->d_parent
;
936 new_parent
= sysfs_get_dentry(new_parent_sd
);
937 if (IS_ERR(new_parent
)) {
938 error
= PTR_ERR(new_parent
);
944 mutex_lock(&old_parent
->d_inode
->i_mutex
);
945 if (!mutex_trylock(&new_parent
->d_inode
->i_mutex
)) {
946 mutex_unlock(&old_parent
->d_inode
->i_mutex
);
949 mutex_lock(&sysfs_mutex
);
952 if (sysfs_find_dirent(new_parent_sd
, sd
->s_name
))
956 new_dentry
= d_alloc_name(new_parent
, sd
->s_name
);
961 d_add(new_dentry
, NULL
);
962 d_move(old_dentry
, new_dentry
);
964 /* Remove from old parent's list and insert into new parent's list. */
965 sysfs_unlink_sibling(sd
);
966 sysfs_get(new_parent_sd
);
967 drop_nlink(old_parent
->d_inode
);
968 sysfs_put(sd
->s_parent
);
969 sd
->s_parent
= new_parent_sd
;
970 inc_nlink(new_parent
->d_inode
);
971 sysfs_link_sibling(sd
);
974 mutex_unlock(&sysfs_mutex
);
975 mutex_unlock(&new_parent
->d_inode
->i_mutex
);
976 mutex_unlock(&old_parent
->d_inode
->i_mutex
);
981 mutex_unlock(&sysfs_rename_mutex
);
985 /* Relationship between s_mode and the DT_xxx types */
986 static inline unsigned char dt_type(struct sysfs_dirent
*sd
)
988 return (sd
->s_mode
>> 12) & 15;
991 static int sysfs_readdir(struct file
* filp
, void * dirent
, filldir_t filldir
)
993 struct dentry
*dentry
= filp
->f_path
.dentry
;
994 struct sysfs_dirent
* parent_sd
= dentry
->d_fsdata
;
995 struct sysfs_dirent
*pos
;
998 if (filp
->f_pos
== 0) {
999 ino
= parent_sd
->s_ino
;
1000 if (filldir(dirent
, ".", 1, filp
->f_pos
, ino
, DT_DIR
) == 0)
1003 if (filp
->f_pos
== 1) {
1004 if (parent_sd
->s_parent
)
1005 ino
= parent_sd
->s_parent
->s_ino
;
1007 ino
= parent_sd
->s_ino
;
1008 if (filldir(dirent
, "..", 2, filp
->f_pos
, ino
, DT_DIR
) == 0)
1011 if ((filp
->f_pos
> 1) && (filp
->f_pos
< INT_MAX
)) {
1012 mutex_lock(&sysfs_mutex
);
1014 /* Skip the dentries we have already reported */
1015 pos
= parent_sd
->s_dir
.children
;
1016 while (pos
&& (filp
->f_pos
> pos
->s_ino
))
1017 pos
= pos
->s_sibling
;
1019 for ( ; pos
; pos
= pos
->s_sibling
) {
1025 filp
->f_pos
= ino
= pos
->s_ino
;
1027 if (filldir(dirent
, name
, len
, filp
->f_pos
, ino
,
1032 filp
->f_pos
= INT_MAX
;
1033 mutex_unlock(&sysfs_mutex
);
1039 const struct file_operations sysfs_dir_operations
= {
1040 .read
= generic_read_dir
,
1041 .readdir
= sysfs_readdir
,
1042 .llseek
= generic_file_llseek
,