The inode structure has used i_mutex as its internal locking
primitive since 2.6.16. The compatibility code to check for
the previous semaphore primitive has been removed. However,
the wrapper function itself is being kept because it's entirely
possible this primitive will change again to allow finer grained
locking.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>