suse man page for lock_may_write

LOCK_MAY_WRITE(9)						   The Linux VFS						 LOCK_MAY_WRITE(9)

NAME
       lock_may_write - checks that the region is free of locks

SYNOPSIS
       int lock_may_write(struct inode * inode, loff_t start, unsigned long len);

ARGUMENTS
       inode
	   the inode that is being written

       start
	   the first byte to write

       len
	   the number of bytes to write

DESCRIPTION
       Emulates Windows locking requirements. Whole-file mandatory locks (share modes) can prohibit a write and byte-range POSIX locks can
       prohibit a write if they overlap.

       N.B. this function is only ever called from knfsd and ownership of locks is never checked.

COPYRIGHT
Kernel Hackers Manual 2.6.					     July 2010							 LOCK_MAY_WRITE(9)