#include "sysfs.h"
DECLARE_RWSEM(sysfs_rename_sem);
+spinlock_t sysfs_lock = SPIN_LOCK_UNLOCKED;
static void sysfs_d_iput(struct dentry * dentry, struct inode * inode)
{
struct sysfs_dirent * sd = dentry->d_fsdata;
if (sd) {
- BUG_ON(sd->s_dentry != dentry);
- sd->s_dentry = NULL;
+ /* sd->s_dentry is protected with sysfs_lock. This
+ * allows sysfs_drop_dentry() to dereference it.
+ */
+ spin_lock(&sysfs_lock);
+
+ /* The dentry might have been deleted or another
+ * lookup could have happened updating sd->s_dentry to
+ * point the new dentry. Ignore if it isn't pointing
+ * to this dentry.
+ */
+ if (sd->s_dentry == dentry)
+ sd->s_dentry = NULL;
+ spin_unlock(&sysfs_lock);
sysfs_put(sd);
}
iput(inode);
.d_iput = sysfs_d_iput,
};
+static unsigned int sysfs_inode_counter;
+ino_t sysfs_get_inum(void)
+{
+ if (unlikely(sysfs_inode_counter < 3))
+ sysfs_inode_counter = 3;
+ return sysfs_inode_counter++;
+}
+
/*
* Allocates a new sysfs_dirent and links it to the parent sysfs_dirent
*/
-static struct sysfs_dirent * sysfs_new_dirent(struct sysfs_dirent * parent_sd,
- void * element)
+static struct sysfs_dirent * __sysfs_new_dirent(void * element)
{
struct sysfs_dirent * sd;
- sd = kmem_cache_alloc(sysfs_dir_cachep, GFP_KERNEL);
+ sd = kmem_cache_zalloc(sysfs_dir_cachep, GFP_KERNEL);
if (!sd)
return NULL;
- memset(sd, 0, sizeof(*sd));
+ sd->s_ino = sysfs_get_inum();
atomic_set(&sd->s_count, 1);
atomic_set(&sd->s_event, 1);
INIT_LIST_HEAD(&sd->s_children);
- list_add(&sd->s_sibling, &parent_sd->s_children);
+ INIT_LIST_HEAD(&sd->s_sibling);
sd->s_element = element;
return sd;
}
+static void __sysfs_list_dirent(struct sysfs_dirent *parent_sd,
+ struct sysfs_dirent *sd)
+{
+ if (sd)
+ list_add(&sd->s_sibling, &parent_sd->s_children);
+}
+
+static struct sysfs_dirent * sysfs_new_dirent(struct sysfs_dirent *parent_sd,
+ void * element)
+{
+ struct sysfs_dirent *sd;
+ sd = __sysfs_new_dirent(element);
+ __sysfs_list_dirent(parent_sd, sd);
+ return sd;
+}
+
/*
*
* Return -EEXIST if there is already a sysfs element with the same name for
}
-int sysfs_make_dirent(struct sysfs_dirent * parent_sd, struct dentry * dentry,
- void * element, umode_t mode, int type)
+static struct sysfs_dirent *
+__sysfs_make_dirent(struct dentry *dentry, void *element, mode_t mode, int type)
{
struct sysfs_dirent * sd;
- sd = sysfs_new_dirent(parent_sd, element);
+ sd = __sysfs_new_dirent(element);
if (!sd)
- return -ENOMEM;
+ goto out;
sd->s_mode = mode;
sd->s_type = type;
dentry->d_op = &sysfs_dentry_ops;
}
- return 0;
+out:
+ return sd;
+}
+
+int sysfs_make_dirent(struct sysfs_dirent * parent_sd, struct dentry * dentry,
+ void * element, umode_t mode, int type)
+{
+ struct sysfs_dirent *sd;
+
+ sd = __sysfs_make_dirent(dentry, element, mode, type);
+ __sysfs_list_dirent(parent_sd, sd);
+
+ return sd ? 0 : -ENOMEM;
}
static int init_dir(struct inode * inode)
/**
* sysfs_create_dir - create a directory for an object.
- * @parent: parent parent object.
* @kobj: object we're creating directory for.
+ * @shadow_parent: parent parent object.
*/
-int sysfs_create_dir(struct kobject * kobj)
+int sysfs_create_dir(struct kobject * kobj, struct dentry *shadow_parent)
{
struct dentry * dentry = NULL;
struct dentry * parent;
BUG_ON(!kobj);
- if (kobj->parent)
+ if (shadow_parent)
+ parent = shadow_parent;
+ else if (kobj->parent)
parent = kobj->parent->dentry;
else if (sysfs_mount && sysfs_mount->mnt_sb)
parent = sysfs_mount->mnt_sb->s_root;
}
dentry->d_fsdata = sysfs_get(sd);
+ /* protect sd->s_dentry against sysfs_d_iput */
+ spin_lock(&sysfs_lock);
sd->s_dentry = dentry;
+ spin_unlock(&sysfs_lock);
error = sysfs_create(dentry, (attr->mode & S_IALLUGO) | S_IFREG, init);
if (error) {
sysfs_put(sd);
int err = 0;
dentry->d_fsdata = sysfs_get(sd);
+ /* protect sd->s_dentry against sysfs_d_iput */
+ spin_lock(&sysfs_lock);
sd->s_dentry = dentry;
+ spin_unlock(&sysfs_lock);
err = sysfs_create(dentry, S_IFLNK|S_IRWXUGO, init_symlink);
if (!err) {
dentry->d_op = &sysfs_dentry_ops;
return ERR_PTR(err);
}
-struct inode_operations sysfs_dir_inode_operations = {
+const struct inode_operations sysfs_dir_inode_operations = {
.lookup = sysfs_lookup,
.setattr = sysfs_setattr,
};
}
-/**
- * sysfs_remove_dir - remove an object's directory.
- * @kobj: object.
- *
- * The only thing special about this is that we remove any files in
- * the directory before we remove the directory, and we've inlined
- * what used to be sysfs_rmdir() below, instead of calling separately.
- */
-
-void sysfs_remove_dir(struct kobject * kobj)
+static void __sysfs_remove_dir(struct dentry *dentry)
{
- struct dentry * dentry = dget(kobj->dentry);
struct sysfs_dirent * parent_sd;
struct sysfs_dirent * sd, * tmp;
+ dget(dentry);
if (!dentry)
return;
* Drop reference from dget() on entrance.
*/
dput(dentry);
+}
+
+/**
+ * sysfs_remove_dir - remove an object's directory.
+ * @kobj: object.
+ *
+ * The only thing special about this is that we remove any files in
+ * the directory before we remove the directory, and we've inlined
+ * what used to be sysfs_rmdir() below, instead of calling separately.
+ */
+
+void sysfs_remove_dir(struct kobject * kobj)
+{
+ __sysfs_remove_dir(kobj->dentry);
kobj->dentry = NULL;
}
-int sysfs_rename_dir(struct kobject * kobj, const char *new_name)
+int sysfs_rename_dir(struct kobject * kobj, struct dentry *new_parent,
+ const char *new_name)
{
int error = 0;
- struct dentry * new_dentry, * parent;
+ struct dentry * new_dentry;
- if (!strcmp(kobject_name(kobj), new_name))
- return -EINVAL;
-
- if (!kobj->parent)
- return -EINVAL;
+ if (!new_parent)
+ return -EFAULT;
down_write(&sysfs_rename_sem);
- parent = kobj->parent->dentry;
-
- mutex_lock(&parent->d_inode->i_mutex);
+ mutex_lock(&new_parent->d_inode->i_mutex);
- new_dentry = lookup_one_len(new_name, parent, strlen(new_name));
+ new_dentry = lookup_one_len(new_name, new_parent, strlen(new_name));
if (!IS_ERR(new_dentry)) {
- if (!new_dentry->d_inode) {
+ /* By allowing two different directories with the
+ * same d_parent we allow this routine to move
+ * between different shadows of the same directory
+ */
+ if (kobj->dentry->d_parent->d_inode != new_parent->d_inode)
+ return -EINVAL;
+ else if (new_dentry->d_parent->d_inode != new_parent->d_inode)
+ error = -EINVAL;
+ else if (new_dentry == kobj->dentry)
+ error = -EINVAL;
+ else if (!new_dentry->d_inode) {
error = kobject_set_name(kobj, "%s", new_name);
if (!error) {
+ struct sysfs_dirent *sd, *parent_sd;
+
d_add(new_dentry, NULL);
d_move(kobj->dentry, new_dentry);
+
+ sd = kobj->dentry->d_fsdata;
+ parent_sd = new_parent->d_fsdata;
+
+ list_del_init(&sd->s_sibling);
+ list_add(&sd->s_sibling, &parent_sd->s_children);
}
else
d_drop(new_dentry);
error = -EEXIST;
dput(new_dentry);
}
- mutex_unlock(&parent->d_inode->i_mutex);
+ mutex_unlock(&new_parent->d_inode->i_mutex);
up_write(&sysfs_rename_sem);
return error;
new_parent_dentry = new_parent ?
new_parent->dentry : sysfs_mount->mnt_sb->s_root;
+ if (old_parent_dentry->d_inode == new_parent_dentry->d_inode)
+ return 0; /* nothing to move */
again:
mutex_lock(&old_parent_dentry->d_inode->i_mutex);
if (!mutex_trylock(&new_parent_dentry->d_inode->i_mutex)) {
switch (i) {
case 0:
- ino = dentry->d_inode->i_ino;
+ ino = parent_sd->s_ino;
if (filldir(dirent, ".", 1, i, ino, DT_DIR) < 0)
break;
filp->f_pos++;
name = sysfs_get_name(next);
len = strlen(name);
- if (next->s_dentry)
- ino = next->s_dentry->d_inode->i_ino;
- else
- ino = iunique(sysfs_sb, 2);
+ ino = next->s_ino;
if (filldir(dirent, name, len, filp->f_pos, ino,
dt_type(next)) < 0)
return offset;
}
+
+/**
+ * sysfs_make_shadowed_dir - Setup so a directory can be shadowed
+ * @kobj: object we're creating shadow of.
+ */
+
+int sysfs_make_shadowed_dir(struct kobject *kobj,
+ void * (*follow_link)(struct dentry *, struct nameidata *))
+{
+ struct inode *inode;
+ struct inode_operations *i_op;
+
+ inode = kobj->dentry->d_inode;
+ if (inode->i_op != &sysfs_dir_inode_operations)
+ return -EINVAL;
+
+ i_op = kmalloc(sizeof(*i_op), GFP_KERNEL);
+ if (!i_op)
+ return -ENOMEM;
+
+ memcpy(i_op, &sysfs_dir_inode_operations, sizeof(*i_op));
+ i_op->follow_link = follow_link;
+
+ /* Locking of inode->i_op?
+ * Since setting i_op is a single word write and they
+ * are atomic we should be ok here.
+ */
+ inode->i_op = i_op;
+ return 0;
+}
+
+/**
+ * sysfs_create_shadow_dir - create a shadow directory for an object.
+ * @kobj: object we're creating directory for.
+ *
+ * sysfs_make_shadowed_dir must already have been called on this
+ * directory.
+ */
+
+struct dentry *sysfs_create_shadow_dir(struct kobject *kobj)
+{
+ struct sysfs_dirent *sd;
+ struct dentry *parent, *dir, *shadow;
+ struct inode *inode;
+
+ dir = kobj->dentry;
+ inode = dir->d_inode;
+ parent = dir->d_parent;
+ shadow = ERR_PTR(-EINVAL);
+ if (!sysfs_is_shadowed_inode(inode))
+ goto out;
+
+ shadow = d_alloc(parent, &dir->d_name);
+ if (!shadow)
+ goto nomem;
+
+ sd = __sysfs_make_dirent(shadow, kobj, inode->i_mode, SYSFS_DIR);
+ if (!sd)
+ goto nomem;
+
+ d_instantiate(shadow, igrab(inode));
+ inc_nlink(inode);
+ inc_nlink(parent->d_inode);
+ shadow->d_op = &sysfs_dentry_ops;
+
+ dget(shadow); /* Extra count - pin the dentry in core */
+
+out:
+ return shadow;
+nomem:
+ dput(shadow);
+ shadow = ERR_PTR(-ENOMEM);
+ goto out;
+}
+
+/**
+ * sysfs_remove_shadow_dir - remove an object's directory.
+ * @shadow: dentry of shadow directory
+ *
+ * The only thing special about this is that we remove any files in
+ * the directory before we remove the directory, and we've inlined
+ * what used to be sysfs_rmdir() below, instead of calling separately.
+ */
+
+void sysfs_remove_shadow_dir(struct dentry *shadow)
+{
+ __sysfs_remove_dir(shadow);
+}
+
const struct file_operations sysfs_dir_operations = {
.open = sysfs_dir_open,
.release = sysfs_dir_close,
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