[Devel] Re: [PATCH 17/25] sysfs: Rewrite rename in terms of sysfs dirents
Eric W. Biederman
ebiederm at xmission.com
Wed Aug 8 08:32:20 PDT 2007
Tejun Heo <htejun at gmail.com> writes:
>> int sysfs_rename_dir(struct kobject * kobj, const char *new_name)
>> {
>> - struct sysfs_dirent *sd;
>> + struct sysfs_dirent *sd = kobj->sd;
>> struct dentry *parent = NULL;
>> struct dentry *old_dentry = NULL, *new_dentry = NULL;
>> const char *dup_name = NULL;
>> @@ -863,42 +863,41 @@ int sysfs_rename_dir(struct kobject * kobj, const char
> *new_name)
>>
>> mutex_lock(&sysfs_rename_mutex);
>>
>> + error = 0;
>> + if (strcmp(sd->s_name, new_name) == 0)
>> + goto out; /* nothing to rename */
>> +
>> /* get the original dentry */
>> old_dentry = sysfs_get_dentry(sd);
>> if (IS_ERR(old_dentry)) {
>> error = PTR_ERR(old_dentry);
>> + goto out;
>> }
>>
>> parent = old_dentry->d_parent;
>>
>> /* lock parent and get dentry for new name */
>> mutex_lock(&parent->d_inode->i_mutex);
>> + mutex_lock(&sysfs_mutex);
>>
>> + error = -EEXIST;
>> + if (sysfs_find_dirent(sd->s_parent, new_name))
>> goto out_unlock;
>>
>> + error = -ENOMEM;
>> + new_dentry = d_alloc_name(parent, new_name);
>> + if (!new_dentry)
>> goto out_unlock;
>>
>> /* rename kobject and sysfs_dirent */
>> error = -ENOMEM;
>> new_name = dup_name = kstrdup(new_name, GFP_KERNEL);
>> if (!new_name)
>> + goto out_unlock;
>>
>> error = kobject_set_name(kobj, "%s", new_name);
>> if (error)
>> + goto out_unlock;
>>
>> mutex_lock(&sysfs_mutex);
>
> sysfs_mutex is being grabbed twice and unlocked twice later.
Ugh. That patch was supposed to remove the inner grab and release of
sysfs_mutex. I guess I somehow failed to move that change all of the
way down to this patch. #18 gets it right for sysfs_move_dir. And
#20 fixes it but yes this patch is broken, and will mess up any
git-bisect badly.
So this patch needs to be respun.
Eric
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