1 /* -*- mode: c; c-basic-offset: 8; -*-
2 * vim: noexpandtab sw=8 ts=8 sts=0:
4 * dir.c - Operations for configfs directories.
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public
8 * License as published by the Free Software Foundation; either
9 * version 2 of the License, or (at your option) any later version.
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 * General Public License for more details.
16 * You should have received a copy of the GNU General Public
17 * License along with this program; if not, write to the
18 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
19 * Boston, MA 021110-1307, USA.
22 * sysfs is Copyright (C) 2001, 2002, 2003 Patrick Mochel
24 * configfs Copyright (C) 2005 Oracle. All rights reserved.
30 #include <linux/mount.h>
31 #include <linux/module.h>
32 #include <linux/slab.h>
34 #include <linux/configfs.h>
35 #include "configfs_internal.h"
37 DECLARE_RWSEM(configfs_rename_sem);
39 * Protects mutations of configfs_dirent linkage together with proper i_mutex
40 * Also protects mutations of symlinks linkage to target configfs_dirent
41 * Mutators of configfs_dirent linkage must *both* have the proper inode locked
42 * and configfs_dirent_lock locked, in that order.
43 * This allows one to safely traverse configfs_dirent trees and symlinks without
44 * having to lock inodes.
46 DEFINE_SPINLOCK(configfs_dirent_lock);
48 static void configfs_d_iput(struct dentry * dentry,
51 struct configfs_dirent * sd = dentry->d_fsdata;
54 BUG_ON(sd->s_dentry != dentry);
62 * We _must_ delete our dentries on last dput, as the chain-to-parent
63 * behavior is required to clear the parents of default_groups.
65 static int configfs_d_delete(struct dentry *dentry)
70 static struct dentry_operations configfs_dentry_ops = {
71 .d_iput = configfs_d_iput,
72 /* simple_delete_dentry() isn't exported */
73 .d_delete = configfs_d_delete,
77 * Allocates a new configfs_dirent and links it to the parent configfs_dirent
79 static struct configfs_dirent *configfs_new_dirent(struct configfs_dirent * parent_sd,
82 struct configfs_dirent * sd;
84 sd = kmem_cache_zalloc(configfs_dir_cachep, GFP_KERNEL);
88 atomic_set(&sd->s_count, 1);
89 INIT_LIST_HEAD(&sd->s_links);
90 INIT_LIST_HEAD(&sd->s_children);
91 sd->s_element = element;
92 spin_lock(&configfs_dirent_lock);
93 list_add(&sd->s_sibling, &parent_sd->s_children);
94 spin_unlock(&configfs_dirent_lock);
101 * Return -EEXIST if there is already a configfs element with the same
102 * name for the same parent.
104 * called with parent inode's i_mutex held
106 static int configfs_dirent_exists(struct configfs_dirent *parent_sd,
107 const unsigned char *new)
109 struct configfs_dirent * sd;
111 list_for_each_entry(sd, &parent_sd->s_children, s_sibling) {
113 const unsigned char *existing = configfs_get_name(sd);
114 if (strcmp(existing, new))
125 int configfs_make_dirent(struct configfs_dirent * parent_sd,
126 struct dentry * dentry, void * element,
127 umode_t mode, int type)
129 struct configfs_dirent * sd;
131 sd = configfs_new_dirent(parent_sd, element);
137 sd->s_dentry = dentry;
139 dentry->d_fsdata = configfs_get(sd);
140 dentry->d_op = &configfs_dentry_ops;
146 static int init_dir(struct inode * inode)
148 inode->i_op = &configfs_dir_inode_operations;
149 inode->i_fop = &configfs_dir_operations;
151 /* directory inodes start off with i_nlink == 2 (for "." entry) */
156 static int configfs_init_file(struct inode * inode)
158 inode->i_size = PAGE_SIZE;
159 inode->i_fop = &configfs_file_operations;
163 static int init_symlink(struct inode * inode)
165 inode->i_op = &configfs_symlink_inode_operations;
169 static int create_dir(struct config_item * k, struct dentry * p,
173 umode_t mode = S_IFDIR| S_IRWXU | S_IRUGO | S_IXUGO;
175 error = configfs_dirent_exists(p->d_fsdata, d->d_name.name);
177 error = configfs_make_dirent(p->d_fsdata, d, k, mode,
180 error = configfs_create(d, mode, init_dir);
182 inc_nlink(p->d_inode);
183 (d)->d_op = &configfs_dentry_ops;
185 struct configfs_dirent *sd = d->d_fsdata;
187 spin_lock(&configfs_dirent_lock);
188 list_del_init(&sd->s_sibling);
189 spin_unlock(&configfs_dirent_lock);
199 * configfs_create_dir - create a directory for an config_item.
200 * @item: config_itemwe're creating directory for.
201 * @dentry: config_item's dentry.
204 static int configfs_create_dir(struct config_item * item, struct dentry *dentry)
206 struct dentry * parent;
212 parent = item->ci_parent->ci_dentry;
213 else if (configfs_mount && configfs_mount->mnt_sb)
214 parent = configfs_mount->mnt_sb->s_root;
218 error = create_dir(item,parent,dentry);
220 item->ci_dentry = dentry;
224 int configfs_create_link(struct configfs_symlink *sl,
225 struct dentry *parent,
226 struct dentry *dentry)
229 umode_t mode = S_IFLNK | S_IRWXUGO;
231 err = configfs_make_dirent(parent->d_fsdata, dentry, sl, mode,
234 err = configfs_create(dentry, mode, init_symlink);
236 dentry->d_op = &configfs_dentry_ops;
238 struct configfs_dirent *sd = dentry->d_fsdata;
240 spin_lock(&configfs_dirent_lock);
241 list_del_init(&sd->s_sibling);
242 spin_unlock(&configfs_dirent_lock);
250 static void remove_dir(struct dentry * d)
252 struct dentry * parent = dget(d->d_parent);
253 struct configfs_dirent * sd;
256 spin_lock(&configfs_dirent_lock);
257 list_del_init(&sd->s_sibling);
258 spin_unlock(&configfs_dirent_lock);
261 simple_rmdir(parent->d_inode,d);
263 pr_debug(" o %s removing done (%d)\n",d->d_name.name,
264 atomic_read(&d->d_count));
270 * configfs_remove_dir - remove an config_item's directory.
271 * @item: config_item we're removing.
273 * The only thing special about this is that we remove any files in
274 * the directory before we remove the directory, and we've inlined
275 * what used to be configfs_rmdir() below, instead of calling separately.
278 static void configfs_remove_dir(struct config_item * item)
280 struct dentry * dentry = dget(item->ci_dentry);
287 * Drop reference from dget() on entrance.
293 /* attaches attribute's configfs_dirent to the dentry corresponding to the
296 static int configfs_attach_attr(struct configfs_dirent * sd, struct dentry * dentry)
298 struct configfs_attribute * attr = sd->s_element;
301 dentry->d_fsdata = configfs_get(sd);
302 sd->s_dentry = dentry;
303 error = configfs_create(dentry, (attr->ca_mode & S_IALLUGO) | S_IFREG,
310 dentry->d_op = &configfs_dentry_ops;
316 static struct dentry * configfs_lookup(struct inode *dir,
317 struct dentry *dentry,
318 struct nameidata *nd)
320 struct configfs_dirent * parent_sd = dentry->d_parent->d_fsdata;
321 struct configfs_dirent * sd;
325 list_for_each_entry(sd, &parent_sd->s_children, s_sibling) {
326 if (sd->s_type & CONFIGFS_NOT_PINNED) {
327 const unsigned char * name = configfs_get_name(sd);
329 if (strcmp(name, dentry->d_name.name))
333 err = configfs_attach_attr(sd, dentry);
340 * If it doesn't exist and it isn't a NOT_PINNED item,
341 * it must be negative.
343 return simple_lookup(dir, dentry, nd);
350 * Only subdirectories count here. Files (CONFIGFS_NOT_PINNED) are
351 * attributes and are removed by rmdir(). We recurse, taking i_mutex
352 * on all children that are candidates for default detach. If the
353 * result is clean, then configfs_detach_group() will handle dropping
354 * i_mutex. If there is an error, the caller will clean up the i_mutex
355 * holders via configfs_detach_rollback().
357 static int configfs_detach_prep(struct dentry *dentry)
359 struct configfs_dirent *parent_sd = dentry->d_fsdata;
360 struct configfs_dirent *sd;
364 if (!list_empty(&parent_sd->s_links))
368 list_for_each_entry(sd, &parent_sd->s_children, s_sibling) {
369 if (sd->s_type & CONFIGFS_NOT_PINNED)
371 if (sd->s_type & CONFIGFS_USET_DEFAULT) {
372 mutex_lock(&sd->s_dentry->d_inode->i_mutex);
373 /* Mark that we've taken i_mutex */
374 sd->s_type |= CONFIGFS_USET_DROPPING;
377 * Yup, recursive. If there's a problem, blame
378 * deep nesting of default_groups
380 ret = configfs_detach_prep(sd->s_dentry);
394 * Walk the tree, dropping i_mutex wherever CONFIGFS_USET_DROPPING is
397 static void configfs_detach_rollback(struct dentry *dentry)
399 struct configfs_dirent *parent_sd = dentry->d_fsdata;
400 struct configfs_dirent *sd;
402 list_for_each_entry(sd, &parent_sd->s_children, s_sibling) {
403 if (sd->s_type & CONFIGFS_USET_DEFAULT) {
404 configfs_detach_rollback(sd->s_dentry);
406 if (sd->s_type & CONFIGFS_USET_DROPPING) {
407 sd->s_type &= ~CONFIGFS_USET_DROPPING;
408 mutex_unlock(&sd->s_dentry->d_inode->i_mutex);
414 static void detach_attrs(struct config_item * item)
416 struct dentry * dentry = dget(item->ci_dentry);
417 struct configfs_dirent * parent_sd;
418 struct configfs_dirent * sd, * tmp;
423 pr_debug("configfs %s: dropping attrs for dir\n",
424 dentry->d_name.name);
426 parent_sd = dentry->d_fsdata;
427 list_for_each_entry_safe(sd, tmp, &parent_sd->s_children, s_sibling) {
428 if (!sd->s_element || !(sd->s_type & CONFIGFS_NOT_PINNED))
430 spin_lock(&configfs_dirent_lock);
431 list_del_init(&sd->s_sibling);
432 spin_unlock(&configfs_dirent_lock);
433 configfs_drop_dentry(sd, dentry);
438 * Drop reference from dget() on entrance.
443 static int populate_attrs(struct config_item *item)
445 struct config_item_type *t = item->ci_type;
446 struct configfs_attribute *attr;
453 for (i = 0; (attr = t->ct_attrs[i]) != NULL; i++) {
454 if ((error = configfs_create_file(item, attr)))
465 static int configfs_attach_group(struct config_item *parent_item,
466 struct config_item *item,
467 struct dentry *dentry);
468 static void configfs_detach_group(struct config_item *item);
470 static void detach_groups(struct config_group *group)
472 struct dentry * dentry = dget(group->cg_item.ci_dentry);
473 struct dentry *child;
474 struct configfs_dirent *parent_sd;
475 struct configfs_dirent *sd, *tmp;
480 parent_sd = dentry->d_fsdata;
481 list_for_each_entry_safe(sd, tmp, &parent_sd->s_children, s_sibling) {
482 if (!sd->s_element ||
483 !(sd->s_type & CONFIGFS_USET_DEFAULT))
486 child = sd->s_dentry;
488 configfs_detach_group(sd->s_element);
489 child->d_inode->i_flags |= S_DEAD;
492 * From rmdir/unregister, a configfs_detach_prep() pass
493 * has taken our i_mutex for us. Drop it.
494 * From mkdir/register cleanup, there is no sem held.
496 if (sd->s_type & CONFIGFS_USET_DROPPING)
497 mutex_unlock(&child->d_inode->i_mutex);
504 * Drop reference from dget() on entrance.
510 * This fakes mkdir(2) on a default_groups[] entry. It
511 * creates a dentry, attachs it, and then does fixup
514 * We could, perhaps, tweak our parent's ->mkdir for a minute and
515 * try using vfs_mkdir. Just a thought.
517 static int create_default_group(struct config_group *parent_group,
518 struct config_group *group)
522 struct configfs_dirent *sd;
523 /* We trust the caller holds a reference to parent */
524 struct dentry *child, *parent = parent_group->cg_item.ci_dentry;
526 if (!group->cg_item.ci_name)
527 group->cg_item.ci_name = group->cg_item.ci_namebuf;
528 name.name = group->cg_item.ci_name;
529 name.len = strlen(name.name);
530 name.hash = full_name_hash(name.name, name.len);
533 child = d_alloc(parent, &name);
537 ret = configfs_attach_group(&parent_group->cg_item,
538 &group->cg_item, child);
540 sd = child->d_fsdata;
541 sd->s_type |= CONFIGFS_USET_DEFAULT;
551 static int populate_groups(struct config_group *group)
553 struct config_group *new_group;
554 struct dentry *dentry = group->cg_item.ci_dentry;
558 if (group->default_groups) {
560 * FYI, we're faking mkdir here
561 * I'm not sure we need this semaphore, as we're called
562 * from our parent's mkdir. That holds our parent's
563 * i_mutex, so afaik lookup cannot continue through our
564 * parent to find us, let alone mess with our tree.
565 * That said, taking our i_mutex is closer to mkdir
566 * emulation, and shouldn't hurt.
568 mutex_lock_nested(&dentry->d_inode->i_mutex, I_MUTEX_CHILD);
570 for (i = 0; group->default_groups[i]; i++) {
571 new_group = group->default_groups[i];
573 ret = create_default_group(group, new_group);
578 mutex_unlock(&dentry->d_inode->i_mutex);
582 detach_groups(group);
588 * All of link_obj/unlink_obj/link_group/unlink_group require that
589 * subsys->su_mutex is held.
592 static void unlink_obj(struct config_item *item)
594 struct config_group *group;
596 group = item->ci_group;
598 list_del_init(&item->ci_entry);
600 item->ci_group = NULL;
601 item->ci_parent = NULL;
603 /* Drop the reference for ci_entry */
604 config_item_put(item);
606 /* Drop the reference for ci_parent */
607 config_group_put(group);
611 static void link_obj(struct config_item *parent_item, struct config_item *item)
614 * Parent seems redundant with group, but it makes certain
615 * traversals much nicer.
617 item->ci_parent = parent_item;
620 * We hold a reference on the parent for the child's ci_parent
623 item->ci_group = config_group_get(to_config_group(parent_item));
624 list_add_tail(&item->ci_entry, &item->ci_group->cg_children);
627 * We hold a reference on the child for ci_entry on the parent's
630 config_item_get(item);
633 static void unlink_group(struct config_group *group)
636 struct config_group *new_group;
638 if (group->default_groups) {
639 for (i = 0; group->default_groups[i]; i++) {
640 new_group = group->default_groups[i];
641 unlink_group(new_group);
645 group->cg_subsys = NULL;
646 unlink_obj(&group->cg_item);
649 static void link_group(struct config_group *parent_group, struct config_group *group)
652 struct config_group *new_group;
653 struct configfs_subsystem *subsys = NULL; /* gcc is a turd */
655 link_obj(&parent_group->cg_item, &group->cg_item);
657 if (parent_group->cg_subsys)
658 subsys = parent_group->cg_subsys;
659 else if (configfs_is_root(&parent_group->cg_item))
660 subsys = to_configfs_subsystem(group);
663 group->cg_subsys = subsys;
665 if (group->default_groups) {
666 for (i = 0; group->default_groups[i]; i++) {
667 new_group = group->default_groups[i];
668 link_group(group, new_group);
674 * The goal is that configfs_attach_item() (and
675 * configfs_attach_group()) can be called from either the VFS or this
676 * module. That is, they assume that the items have been created,
677 * the dentry allocated, and the dcache is all ready to go.
679 * If they fail, they must clean up after themselves as if they
680 * had never been called. The caller (VFS or local function) will
681 * handle cleaning up the dcache bits.
683 * configfs_detach_group() and configfs_detach_item() behave similarly on
684 * the way out. They assume that the proper semaphores are held, they
685 * clean up the configfs items, and they expect their callers will
686 * handle the dcache bits.
688 static int configfs_attach_item(struct config_item *parent_item,
689 struct config_item *item,
690 struct dentry *dentry)
694 ret = configfs_create_dir(item, dentry);
696 ret = populate_attrs(item);
698 configfs_remove_dir(item);
706 static void configfs_detach_item(struct config_item *item)
709 configfs_remove_dir(item);
712 static int configfs_attach_group(struct config_item *parent_item,
713 struct config_item *item,
714 struct dentry *dentry)
717 struct configfs_dirent *sd;
719 ret = configfs_attach_item(parent_item, item, dentry);
721 sd = dentry->d_fsdata;
722 sd->s_type |= CONFIGFS_USET_DIR;
724 ret = populate_groups(to_config_group(item));
726 configfs_detach_item(item);
734 static void configfs_detach_group(struct config_item *item)
736 detach_groups(to_config_group(item));
737 configfs_detach_item(item);
741 * After the item has been detached from the filesystem view, we are
742 * ready to tear it out of the hierarchy. Notify the client before
743 * we do that so they can perform any cleanup that requires
744 * navigating the hierarchy. A client does not need to provide this
745 * callback. The subsystem semaphore MUST be held by the caller, and
746 * references must be valid for both items. It also assumes the
747 * caller has validated ci_type.
749 static void client_disconnect_notify(struct config_item *parent_item,
750 struct config_item *item)
752 struct config_item_type *type;
754 type = parent_item->ci_type;
757 if (type->ct_group_ops && type->ct_group_ops->disconnect_notify)
758 type->ct_group_ops->disconnect_notify(to_config_group(parent_item),
763 * Drop the initial reference from make_item()/make_group()
764 * This function assumes that reference is held on item
765 * and that item holds a valid reference to the parent. Also, it
766 * assumes the caller has validated ci_type.
768 static void client_drop_item(struct config_item *parent_item,
769 struct config_item *item)
771 struct config_item_type *type;
773 type = parent_item->ci_type;
777 * If ->drop_item() exists, it is responsible for the
780 if (type->ct_group_ops && type->ct_group_ops->drop_item)
781 type->ct_group_ops->drop_item(to_config_group(parent_item),
784 config_item_put(item);
788 static void configfs_dump_one(struct configfs_dirent *sd, int level)
790 printk(KERN_INFO "%*s\"%s\":\n", level, " ", configfs_get_name(sd));
792 #define type_print(_type) if (sd->s_type & _type) printk(KERN_INFO "%*s %s\n", level, " ", #_type);
793 type_print(CONFIGFS_ROOT);
794 type_print(CONFIGFS_DIR);
795 type_print(CONFIGFS_ITEM_ATTR);
796 type_print(CONFIGFS_ITEM_LINK);
797 type_print(CONFIGFS_USET_DIR);
798 type_print(CONFIGFS_USET_DEFAULT);
799 type_print(CONFIGFS_USET_DROPPING);
803 static int configfs_dump(struct configfs_dirent *sd, int level)
805 struct configfs_dirent *child_sd;
808 configfs_dump_one(sd, level);
810 if (!(sd->s_type & (CONFIGFS_DIR|CONFIGFS_ROOT)))
813 list_for_each_entry(child_sd, &sd->s_children, s_sibling) {
814 ret = configfs_dump(child_sd, level + 2);
825 * configfs_depend_item() and configfs_undepend_item()
827 * WARNING: Do not call these from a configfs callback!
829 * This describes these functions and their helpers.
831 * Allow another kernel system to depend on a config_item. If this
832 * happens, the item cannot go away until the dependant can live without
833 * it. The idea is to give client modules as simple an interface as
834 * possible. When a system asks them to depend on an item, they just
835 * call configfs_depend_item(). If the item is live and the client
836 * driver is in good shape, we'll happily do the work for them.
838 * Why is the locking complex? Because configfs uses the VFS to handle
839 * all locking, but this function is called outside the normal
840 * VFS->configfs path. So it must take VFS locks to prevent the
841 * VFS->configfs stuff (configfs_mkdir(), configfs_rmdir(), etc). This is
842 * why you can't call these functions underneath configfs callbacks.
844 * Note, btw, that this can be called at *any* time, even when a configfs
845 * subsystem isn't registered, or when configfs is loading or unloading.
846 * Just like configfs_register_subsystem(). So we take the same
847 * precautions. We pin the filesystem. We lock each i_mutex _in_order_
848 * on our way down the tree. If we can find the target item in the
849 * configfs tree, it must be part of the subsystem tree as well, so we
850 * do not need the subsystem semaphore. Holding the i_mutex chain locks
851 * out mkdir() and rmdir(), who might be racing us.
855 * configfs_depend_prep()
857 * Only subdirectories count here. Files (CONFIGFS_NOT_PINNED) are
858 * attributes. This is similar but not the same to configfs_detach_prep().
859 * Note that configfs_detach_prep() expects the parent to be locked when it
860 * is called, but we lock the parent *inside* configfs_depend_prep(). We
861 * do that so we can unlock it if we find nothing.
863 * Here we do a depth-first search of the dentry hierarchy looking for
864 * our object. We take i_mutex on each step of the way down. IT IS
865 * ESSENTIAL THAT i_mutex LOCKING IS ORDERED. If we come back up a branch,
866 * we'll drop the i_mutex.
868 * If the target is not found, -ENOENT is bubbled up and we have released
869 * all locks. If the target was found, the locks will be cleared by
870 * configfs_depend_rollback().
872 * This adds a requirement that all config_items be unique!
874 * This is recursive because the locking traversal is tricky. There isn't
875 * much on the stack, though, so folks that need this function - be careful
876 * about your stack! Patches will be accepted to make it iterative.
878 static int configfs_depend_prep(struct dentry *origin,
879 struct config_item *target)
881 struct configfs_dirent *child_sd, *sd = origin->d_fsdata;
884 BUG_ON(!origin || !sd);
886 /* Lock this guy on the way down */
887 mutex_lock(&sd->s_dentry->d_inode->i_mutex);
888 if (sd->s_element == target) /* Boo-yah */
891 list_for_each_entry(child_sd, &sd->s_children, s_sibling) {
892 if (child_sd->s_type & CONFIGFS_DIR) {
893 ret = configfs_depend_prep(child_sd->s_dentry,
896 goto out; /* Child path boo-yah */
900 /* We looped all our children and didn't find target */
901 mutex_unlock(&sd->s_dentry->d_inode->i_mutex);
909 * This is ONLY called if configfs_depend_prep() did its job. So we can
910 * trust the entire path from item back up to origin.
912 * We walk backwards from item, unlocking each i_mutex. We finish by
915 static void configfs_depend_rollback(struct dentry *origin,
916 struct config_item *item)
918 struct dentry *dentry = item->ci_dentry;
920 while (dentry != origin) {
921 mutex_unlock(&dentry->d_inode->i_mutex);
922 dentry = dentry->d_parent;
925 mutex_unlock(&origin->d_inode->i_mutex);
928 int configfs_depend_item(struct configfs_subsystem *subsys,
929 struct config_item *target)
932 struct configfs_dirent *p, *root_sd, *subsys_sd = NULL;
933 struct config_item *s_item = &subsys->su_group.cg_item;
936 * Pin the configfs filesystem. This means we can safely access
937 * the root of the configfs filesystem.
939 ret = configfs_pin_fs();
944 * Next, lock the root directory. We're going to check that the
945 * subsystem is really registered, and so we need to lock out
946 * configfs_[un]register_subsystem().
948 mutex_lock(&configfs_sb->s_root->d_inode->i_mutex);
950 root_sd = configfs_sb->s_root->d_fsdata;
952 list_for_each_entry(p, &root_sd->s_children, s_sibling) {
953 if (p->s_type & CONFIGFS_DIR) {
954 if (p->s_element == s_item) {
966 /* Ok, now we can trust subsys/s_item */
968 /* Scan the tree, locking i_mutex recursively, return 0 if found */
969 ret = configfs_depend_prep(subsys_sd->s_dentry, target);
973 /* We hold all i_mutexes from the subsystem down to the target */
974 p = target->ci_dentry->d_fsdata;
975 p->s_dependent_count += 1;
977 configfs_depend_rollback(subsys_sd->s_dentry, target);
980 mutex_unlock(&configfs_sb->s_root->d_inode->i_mutex);
983 * If we succeeded, the fs is pinned via other methods. If not,
984 * we're done with it anyway. So release_fs() is always right.
986 configfs_release_fs();
990 EXPORT_SYMBOL(configfs_depend_item);
993 * Release the dependent linkage. This is much simpler than
994 * configfs_depend_item() because we know that that the client driver is
995 * pinned, thus the subsystem is pinned, and therefore configfs is pinned.
997 void configfs_undepend_item(struct configfs_subsystem *subsys,
998 struct config_item *target)
1000 struct configfs_dirent *sd;
1003 * Since we can trust everything is pinned, we just need i_mutex
1006 mutex_lock(&target->ci_dentry->d_inode->i_mutex);
1008 sd = target->ci_dentry->d_fsdata;
1009 BUG_ON(sd->s_dependent_count < 1);
1011 sd->s_dependent_count -= 1;
1014 * After this unlock, we cannot trust the item to stay alive!
1015 * DO NOT REFERENCE item after this unlock.
1017 mutex_unlock(&target->ci_dentry->d_inode->i_mutex);
1019 EXPORT_SYMBOL(configfs_undepend_item);
1021 static int configfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
1023 int ret, module_got = 0;
1024 struct config_group *group;
1025 struct config_item *item;
1026 struct config_item *parent_item;
1027 struct configfs_subsystem *subsys;
1028 struct configfs_dirent *sd;
1029 struct config_item_type *type;
1030 struct module *owner = NULL;
1033 if (dentry->d_parent == configfs_sb->s_root) {
1038 sd = dentry->d_parent->d_fsdata;
1039 if (!(sd->s_type & CONFIGFS_USET_DIR)) {
1044 /* Get a working ref for the duration of this function */
1045 parent_item = configfs_get_config_item(dentry->d_parent);
1046 type = parent_item->ci_type;
1047 subsys = to_config_group(parent_item)->cg_subsys;
1050 if (!type || !type->ct_group_ops ||
1051 (!type->ct_group_ops->make_group &&
1052 !type->ct_group_ops->make_item)) {
1053 ret = -EPERM; /* Lack-of-mkdir returns -EPERM */
1057 name = kmalloc(dentry->d_name.len + 1, GFP_KERNEL);
1063 snprintf(name, dentry->d_name.len + 1, "%s", dentry->d_name.name);
1065 mutex_lock(&subsys->su_mutex);
1068 if (type->ct_group_ops->make_group) {
1069 group = type->ct_group_ops->make_group(to_config_group(parent_item), name);
1071 link_group(to_config_group(parent_item), group);
1072 item = &group->cg_item;
1075 item = type->ct_group_ops->make_item(to_config_group(parent_item), name);
1077 link_obj(parent_item, item);
1079 mutex_unlock(&subsys->su_mutex);
1084 * If item == NULL, then link_obj() was never called.
1085 * There are no extra references to clean up.
1092 * link_obj() has been called (via link_group() for groups).
1093 * From here on out, errors must clean that up.
1096 type = item->ci_type;
1102 owner = type->ct_owner;
1103 if (!try_module_get(owner)) {
1109 * I hate doing it this way, but if there is
1110 * an error, module_put() probably should
1111 * happen after any cleanup.
1116 ret = configfs_attach_group(parent_item, item, dentry);
1118 ret = configfs_attach_item(parent_item, item, dentry);
1122 /* Tear down everything we built up */
1123 mutex_lock(&subsys->su_mutex);
1125 client_disconnect_notify(parent_item, item);
1127 unlink_group(group);
1130 client_drop_item(parent_item, item);
1132 mutex_unlock(&subsys->su_mutex);
1140 * link_obj()/link_group() took a reference from child->parent,
1141 * so the parent is safely pinned. We can drop our working
1144 config_item_put(parent_item);
1150 static int configfs_rmdir(struct inode *dir, struct dentry *dentry)
1152 struct config_item *parent_item;
1153 struct config_item *item;
1154 struct configfs_subsystem *subsys;
1155 struct configfs_dirent *sd;
1156 struct module *owner = NULL;
1159 if (dentry->d_parent == configfs_sb->s_root)
1162 sd = dentry->d_fsdata;
1163 if (sd->s_type & CONFIGFS_USET_DEFAULT)
1167 * Here's where we check for dependents. We're protected by
1170 if (sd->s_dependent_count)
1173 /* Get a working ref until we have the child */
1174 parent_item = configfs_get_config_item(dentry->d_parent);
1175 subsys = to_config_group(parent_item)->cg_subsys;
1178 if (!parent_item->ci_type) {
1179 config_item_put(parent_item);
1183 ret = configfs_detach_prep(dentry);
1185 configfs_detach_rollback(dentry);
1186 config_item_put(parent_item);
1190 /* Get a working ref for the duration of this function */
1191 item = configfs_get_config_item(dentry);
1193 /* Drop reference from above, item already holds one. */
1194 config_item_put(parent_item);
1197 owner = item->ci_type->ct_owner;
1199 if (sd->s_type & CONFIGFS_USET_DIR) {
1200 configfs_detach_group(item);
1202 mutex_lock(&subsys->su_mutex);
1203 client_disconnect_notify(parent_item, item);
1204 unlink_group(to_config_group(item));
1206 configfs_detach_item(item);
1208 mutex_lock(&subsys->su_mutex);
1209 client_disconnect_notify(parent_item, item);
1213 client_drop_item(parent_item, item);
1214 mutex_unlock(&subsys->su_mutex);
1216 /* Drop our reference from above */
1217 config_item_put(item);
1224 const struct inode_operations configfs_dir_inode_operations = {
1225 .mkdir = configfs_mkdir,
1226 .rmdir = configfs_rmdir,
1227 .symlink = configfs_symlink,
1228 .unlink = configfs_unlink,
1229 .lookup = configfs_lookup,
1230 .setattr = configfs_setattr,
1234 int configfs_rename_dir(struct config_item * item, const char *new_name)
1237 struct dentry * new_dentry, * parent;
1239 if (!strcmp(config_item_name(item), new_name))
1245 down_write(&configfs_rename_sem);
1246 parent = item->parent->dentry;
1248 mutex_lock(&parent->d_inode->i_mutex);
1250 new_dentry = lookup_one_len(new_name, parent, strlen(new_name));
1251 if (!IS_ERR(new_dentry)) {
1252 if (!new_dentry->d_inode) {
1253 error = config_item_set_name(item, "%s", new_name);
1255 d_add(new_dentry, NULL);
1256 d_move(item->dentry, new_dentry);
1259 d_delete(new_dentry);
1264 mutex_unlock(&parent->d_inode->i_mutex);
1265 up_write(&configfs_rename_sem);
1271 static int configfs_dir_open(struct inode *inode, struct file *file)
1273 struct dentry * dentry = file->f_path.dentry;
1274 struct configfs_dirent * parent_sd = dentry->d_fsdata;
1276 mutex_lock(&dentry->d_inode->i_mutex);
1277 file->private_data = configfs_new_dirent(parent_sd, NULL);
1278 mutex_unlock(&dentry->d_inode->i_mutex);
1280 return file->private_data ? 0 : -ENOMEM;
1284 static int configfs_dir_close(struct inode *inode, struct file *file)
1286 struct dentry * dentry = file->f_path.dentry;
1287 struct configfs_dirent * cursor = file->private_data;
1289 mutex_lock(&dentry->d_inode->i_mutex);
1290 spin_lock(&configfs_dirent_lock);
1291 list_del_init(&cursor->s_sibling);
1292 spin_unlock(&configfs_dirent_lock);
1293 mutex_unlock(&dentry->d_inode->i_mutex);
1295 release_configfs_dirent(cursor);
1300 /* Relationship between s_mode and the DT_xxx types */
1301 static inline unsigned char dt_type(struct configfs_dirent *sd)
1303 return (sd->s_mode >> 12) & 15;
1306 static int configfs_readdir(struct file * filp, void * dirent, filldir_t filldir)
1308 struct dentry *dentry = filp->f_path.dentry;
1309 struct configfs_dirent * parent_sd = dentry->d_fsdata;
1310 struct configfs_dirent *cursor = filp->private_data;
1311 struct list_head *p, *q = &cursor->s_sibling;
1313 int i = filp->f_pos;
1317 ino = dentry->d_inode->i_ino;
1318 if (filldir(dirent, ".", 1, i, ino, DT_DIR) < 0)
1324 ino = parent_ino(dentry);
1325 if (filldir(dirent, "..", 2, i, ino, DT_DIR) < 0)
1331 if (filp->f_pos == 2) {
1332 spin_lock(&configfs_dirent_lock);
1333 list_move(q, &parent_sd->s_children);
1334 spin_unlock(&configfs_dirent_lock);
1336 for (p=q->next; p!= &parent_sd->s_children; p=p->next) {
1337 struct configfs_dirent *next;
1341 next = list_entry(p, struct configfs_dirent,
1343 if (!next->s_element)
1346 name = configfs_get_name(next);
1349 ino = next->s_dentry->d_inode->i_ino;
1351 ino = iunique(configfs_sb, 2);
1353 if (filldir(dirent, name, len, filp->f_pos, ino,
1357 spin_lock(&configfs_dirent_lock);
1359 spin_unlock(&configfs_dirent_lock);
1367 static loff_t configfs_dir_lseek(struct file * file, loff_t offset, int origin)
1369 struct dentry * dentry = file->f_path.dentry;
1371 mutex_lock(&dentry->d_inode->i_mutex);
1374 offset += file->f_pos;
1379 mutex_unlock(&file->f_path.dentry->d_inode->i_mutex);
1382 if (offset != file->f_pos) {
1383 file->f_pos = offset;
1384 if (file->f_pos >= 2) {
1385 struct configfs_dirent *sd = dentry->d_fsdata;
1386 struct configfs_dirent *cursor = file->private_data;
1387 struct list_head *p;
1388 loff_t n = file->f_pos - 2;
1390 spin_lock(&configfs_dirent_lock);
1391 list_del(&cursor->s_sibling);
1392 p = sd->s_children.next;
1393 while (n && p != &sd->s_children) {
1394 struct configfs_dirent *next;
1395 next = list_entry(p, struct configfs_dirent,
1397 if (next->s_element)
1401 list_add_tail(&cursor->s_sibling, p);
1402 spin_unlock(&configfs_dirent_lock);
1405 mutex_unlock(&dentry->d_inode->i_mutex);
1409 const struct file_operations configfs_dir_operations = {
1410 .open = configfs_dir_open,
1411 .release = configfs_dir_close,
1412 .llseek = configfs_dir_lseek,
1413 .read = generic_read_dir,
1414 .readdir = configfs_readdir,
1417 int configfs_register_subsystem(struct configfs_subsystem *subsys)
1420 struct config_group *group = &subsys->su_group;
1422 struct dentry *dentry;
1423 struct configfs_dirent *sd;
1425 err = configfs_pin_fs();
1429 if (!group->cg_item.ci_name)
1430 group->cg_item.ci_name = group->cg_item.ci_namebuf;
1432 sd = configfs_sb->s_root->d_fsdata;
1433 link_group(to_config_group(sd->s_element), group);
1435 mutex_lock_nested(&configfs_sb->s_root->d_inode->i_mutex,
1438 name.name = group->cg_item.ci_name;
1439 name.len = strlen(name.name);
1440 name.hash = full_name_hash(name.name, name.len);
1443 dentry = d_alloc(configfs_sb->s_root, &name);
1445 d_add(dentry, NULL);
1447 err = configfs_attach_group(sd->s_element, &group->cg_item,
1455 mutex_unlock(&configfs_sb->s_root->d_inode->i_mutex);
1458 unlink_group(group);
1459 configfs_release_fs();
1465 void configfs_unregister_subsystem(struct configfs_subsystem *subsys)
1467 struct config_group *group = &subsys->su_group;
1468 struct dentry *dentry = group->cg_item.ci_dentry;
1470 if (dentry->d_parent != configfs_sb->s_root) {
1471 printk(KERN_ERR "configfs: Tried to unregister non-subsystem!\n");
1475 mutex_lock_nested(&configfs_sb->s_root->d_inode->i_mutex,
1477 mutex_lock_nested(&dentry->d_inode->i_mutex, I_MUTEX_CHILD);
1478 if (configfs_detach_prep(dentry)) {
1479 printk(KERN_ERR "configfs: Tried to unregister non-empty subsystem!\n");
1481 configfs_detach_group(&group->cg_item);
1482 dentry->d_inode->i_flags |= S_DEAD;
1483 mutex_unlock(&dentry->d_inode->i_mutex);
1487 mutex_unlock(&configfs_sb->s_root->d_inode->i_mutex);
1491 unlink_group(group);
1492 configfs_release_fs();
1495 EXPORT_SYMBOL(configfs_register_subsystem);
1496 EXPORT_SYMBOL(configfs_unregister_subsystem);