centos man page for vfs_setlease

VFS_SETLEASE(9) 						   The Linux VFS						   VFS_SETLEASE(9)

NAME
       vfs_setlease - sets a lease on an open file

SYNOPSIS
       int vfs_setlease(struct file * filp, long arg, struct file_lock ** lease);

ARGUMENTS
       filp
	   file pointer

       arg
	   type of lease to obtain

       lease
	   file_lock to use

DESCRIPTION
       Call this to establish a lease on the file. The (*lease)->fl_lmops->lm_break operation must be set; if not, break_lease will oops!

       This will call the filesystem's setlease file method, if defined. Note that there is no getlease method; instead, the filesystem setlease
       method should call back to setlease to add a lease to the inode's lease list, where fcntl_getlease can find it. Since fcntl_getlease only
       reports whether the current task holds a lease, a cluster filesystem need only do this for leases held by processes on this node.

       There is also no break_lease method; filesystems that handle their own leases should break leases themselves from the filesystem's open,
       create, and (on truncate) setattr methods.

WARNING
       the only current setlease methods exist only to disable leases in certain cases. More vfs changes may be required to allow a full
       filesystem lease implementation.

COPYRIGHT
Kernel Hackers Manual 3.10					     June 2014							   VFS_SETLEASE(9)