Man page 9 : vfs_setlease

vfs_setlease - sets a lease on an open file

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

filp
    file pointer

arg
    type of lease to obtain

lease
    file_lock to use

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 filesystemAqs 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 inodeAqs 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 filesystemAqs open, create, and (on truncate) setattr methods.

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.