nfsd4: Fix filp leak

nfsd4: Fix filp leak

BugLink: http://bugs.launchpad.net/bugs/775809

commit a96e5b90804be8b540d30f4a1453fc87f95b3149 upstream.

23fcf2ec93fb8573a653408316af599939ff9a8e (nfsd4: fix oops on lock failure)

The above patch breaks free path for stp->st_file. If stp was inserted
into sop->so_stateids, we have to free stp->st_file refcount. Because
stp->st_file refcount itself is taken whether or not any refcounts are
taken on the stp->st_file->fi_fds[].

Signed-off-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>