generic: add OFD lock tests
Test OFD locks. Use fcntl F_OFD_SETLK/F_OFD_GETLK, to verify we are
being given correct advices through getlk by kernel.
The basic idea is one setlk routine setting locks via fcntl *_SETLK,
followed by operations like clone, dup then close fd; another
routine getlk getting locks via fcntl *_GETLK.
Firstly in setlk routine process P0, place a lock L0 on an opened
testfile, then do clone or dup and close relative fd.
In getlk process P2, do fcntl *_GETLK with lock L1 after get
notified by setlk routine.
In the end, getlk routine check the returned struct flock.l_type to
see if the lock mechanism works fine.
Test combainations of:
- shared or exclusive lock
- these locks are conflicting or not
- one OFD lock and one POSIX lock
- that open testfile RDONLY or RDWR
- clone with CLONE_FILES or not
- dup and close newfd
[eguan: made some minor non-functional changes]
Signed-off-by: Xiong Zhou <xzhou@redhat.com>
Reviewed-by: Eryu Guan <eguan@redhat.com>
Signed-off-by: Eryu Guan <eguan@redhat.com>