tree 83bba794de7f1f9f9290192f4f95a8ed9c91dfb6
parent 89bec09705d2033b8b765f3c3ac5093f80bd5bc4
author Eric W. Biederman <ebiederm@xmission.com> 1187613390 +0900
committer Greg Kroah-Hartman <gregkh@suse.de> 1192225868 -0700

sysfs: Introduce sysfs_rename_mutex

Looking carefully at the rename code we have a subtle dependency
that the structure of sysfs not change while we are performing
a rename.  If the parent directory of the object we are renaming
changes while the rename is being performed nasty things could
happen when we go to release our locks.

So introduce a sysfs_rename_mutex to prevent this highly
unlikely theoretical issue.

In addition hold sysfs_rename_mutex over all calls to
sysfs_get_dentry. Allowing sysfs_get_dentry to be simplified
in the future.

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>