sysfs: Rewrite sysfs_move_dir in terms of sysfs dirents

This patch rewrites sysfs_move_dir to perform it's checks
as much as possible on the underlying sysfs_dirents instead
of the contents of the dcache, making sysfs_move_dir
more like the rest of the sysfs directory modification
code.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Tejun Heo <htejun@gmail.com>
Cc: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 18 insertions, 16 deletions

diff --git a/fs/sysfs/dir.c b/fs/sysfs/dir.c
index 463c5e3ccf1..da4bb66a610 100644
--- a/fs/sysfs/dir.c
+++ b/fs/sysfs/dir.c
@@ -845,56 +845,58 @@ int sysfs_move_dir(struct kobject *kobj, struct kobject *new_parent_kobj)
         BUG_ON(!sd->s_parent);
         new_parent_sd = new_parent_kobj->sd ? new_parent_kobj->sd : &sysfs_root;
 
+        error = 0;
+        if (sd->s_parent == new_parent_sd)
+                goto out;       /* nothing to move */
+
         /* get dentries */
         old_dentry = sysfs_get_dentry(sd);
         if (IS_ERR(old_dentry)) {
                 error = PTR_ERR(old_dentry);
-                goto out_dput;
+                goto out;
         }
         old_parent = old_dentry->d_parent;
 
         new_parent = sysfs_get_dentry(new_parent_sd);
         if (IS_ERR(new_parent)) {
                 error = PTR_ERR(new_parent);
-                goto out_dput;
+                goto out;
         }
 
-        if (old_parent->d_inode == new_parent->d_inode) {
-                error = 0;
-                goto out_dput;  /* nothing to move */
-        }
 again:
         mutex_lock(&old_parent->d_inode->i_mutex);
         if (!mutex_trylock(&new_parent->d_inode->i_mutex)) {
                 mutex_unlock(&old_parent->d_inode->i_mutex);
                 goto again;
         }
+        mutex_lock(&sysfs_mutex);
 
-        new_dentry = lookup_one_len(kobject_name(kobj), new_parent, strlen(kobject_name(kobj)));
-        if (IS_ERR(new_dentry)) {
-                error = PTR_ERR(new_dentry);
+        error = -EEXIST;
+        if (sysfs_find_dirent(new_parent_sd, sd->s_name))
                 goto out_unlock;
-        } else
-                error = 0;
+
+        error = -ENOMEM;
+        new_dentry = d_alloc_name(new_parent, sd->s_name);
+        if (!new_dentry)
+                goto out_unlock;
+
+        error = 0;
         d_add(new_dentry, NULL);
         d_move(old_dentry, new_dentry);
         dput(new_dentry);
 
         /* Remove from old parent's list and insert into new parent's list. */
-        mutex_lock(&sysfs_mutex);
-
         sysfs_unlink_sibling(sd);
         sysfs_get(new_parent_sd);
         sysfs_put(sd->s_parent);
         sd->s_parent = new_parent_sd;
         sysfs_link_sibling(sd);
 
-        mutex_unlock(&sysfs_mutex);
-
  out_unlock:
+        mutex_unlock(&sysfs_mutex);
         mutex_unlock(&new_parent->d_inode->i_mutex);
         mutex_unlock(&old_parent->d_inode->i_mutex);
- out_dput:
+ out:
         dput(new_parent);
         dput(old_dentry);
         dput(new_dentry);