1 files changed, 175 insertions, 39 deletions

diff --git a/fs/sysfs/dir.c b/fs/sysfs/dir.c
index 511edef8b321..9dcdf556c99c 100644
--- a/fs/sysfs/dir.c
+++ b/fs/sysfs/dir.c
@@ -9,6 +9,7 @@
 #include <linux/module.h>
 #include <linux/kobject.h>
 #include <linux/namei.h>
+#include <asm/semaphore.h>
 #include "sysfs.h"
 
 DECLARE_RWSEM(sysfs_rename_sem);
@@ -32,8 +33,7 @@ static struct dentry_operations sysfs_dentry_ops = {
 /*
  * 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;
 
@@ -45,12 +45,28 @@ static struct sysfs_dirent * sysfs_new_dirent(struct sysfs_dirent * parent_sd,
         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
@@ -77,14 +93,14 @@ int sysfs_dirent_exist(struct sysfs_dirent *parent_sd,
 }
 
 
-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;
@@ -94,7 +110,19 @@ int sysfs_make_dirent(struct sysfs_dirent * parent_sd, struct dentry * dentry,
                 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)
@@ -165,11 +193,11 @@ int sysfs_create_subdir(struct kobject * k, const char * n, struct dentry ** d)
 
 /**
  *      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;
@@ -177,7 +205,9 @@ int sysfs_create_dir(struct kobject * kobj)
 
         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;
@@ -298,21 +328,12 @@ void sysfs_remove_subdir(struct dentry * d)
 }
 
 
-/**
- *      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;
 
@@ -333,32 +354,60 @@ void sysfs_remove_dir(struct kobject * kobj)
          * 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;
-
-        if (!strcmp(kobject_name(kobj), new_name))
-                return -EINVAL;
+        struct dentry * new_dentry;
 
-        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);
@@ -366,7 +415,7 @@ int sysfs_rename_dir(struct kobject * kobj, const char *new_name)
                         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;
@@ -378,12 +427,10 @@ int sysfs_move_dir(struct kobject *kobj, struct kobject *new_parent)
         struct sysfs_dirent *new_parent_sd, *sd;
         int error;
 
-        if (!new_parent)
-                return -EINVAL;
-
         old_parent_dentry = kobj->parent ?
                 kobj->parent->dentry : sysfs_mount->mnt_sb->s_root;
-        new_parent_dentry = new_parent->dentry;
+        new_parent_dentry = new_parent ?
+                new_parent->dentry : sysfs_mount->mnt_sb->s_root;
 
 again:
         mutex_lock(&old_parent_dentry->d_inode->i_mutex);
@@ -547,6 +594,95 @@ static loff_t sysfs_dir_lseek(struct file * file, loff_t offset, int origin)
         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,