[PATCH 50/75] sysfs: Rewrite sysfs_move_dir in terms of sysfs dirents

Greg Kroah-Hartman
2007-10-12T22:48:05Z

From: Eric W. Biederman <ebiederm@xmission.com>

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>
---
fs/sysfs/dir.c | 34 ++++++++++++++++++----------------
1 files changed, 18 insertions(+), 16 deletions(-)

diff --git a/fs/sysfs/dir.c b/fs/sysfs/dir.c
index 463c5e3..da4bb66 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);
--
1.5.3.4