locks: provide a file lease method enabling cluster-coherent leases
Currently leases are only kept locally, so there's no way for a distributed filesystem to enforce them against multiple clients. We're particularly interested in the case of nfsd exporting a cluster filesystem, in which case nfsd needs cluster-coherent leases in order to implement delegations correctly. Also add some documentation. Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
This commit is contained in:
parent
a9933cea7a
commit
f9ffed26d6
24
fs/locks.c
24
fs/locks.c
|
@ -1429,7 +1429,24 @@ out:
|
||||||
* @lease: file_lock to use
|
* @lease: file_lock to use
|
||||||
*
|
*
|
||||||
* Call this to establish a lease on the file.
|
* Call this to establish a lease on the file.
|
||||||
* The fl_lmops fl_break function is required by break_lease
|
* The (*lease)->fl_lmops->fl_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 shoud 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.
|
||||||
*/
|
*/
|
||||||
|
|
||||||
int vfs_setlease(struct file *filp, long arg, struct file_lock **lease)
|
int vfs_setlease(struct file *filp, long arg, struct file_lock **lease)
|
||||||
|
@ -1437,7 +1454,10 @@ int vfs_setlease(struct file *filp, long arg, struct file_lock **lease)
|
||||||
int error;
|
int error;
|
||||||
|
|
||||||
lock_kernel();
|
lock_kernel();
|
||||||
error = setlease(filp, arg, lease);
|
if (filp->f_op && filp->f_op->setlease)
|
||||||
|
error = filp->f_op->setlease(filp, arg, lease);
|
||||||
|
else
|
||||||
|
error = setlease(filp, arg, lease);
|
||||||
unlock_kernel();
|
unlock_kernel();
|
||||||
|
|
||||||
return error;
|
return error;
|
||||||
|
|
|
@ -1122,6 +1122,7 @@ struct file_operations {
|
||||||
int (*flock) (struct file *, int, struct file_lock *);
|
int (*flock) (struct file *, int, struct file_lock *);
|
||||||
ssize_t (*splice_write)(struct pipe_inode_info *, struct file *, loff_t *, size_t, unsigned int);
|
ssize_t (*splice_write)(struct pipe_inode_info *, struct file *, loff_t *, size_t, unsigned int);
|
||||||
ssize_t (*splice_read)(struct file *, loff_t *, struct pipe_inode_info *, size_t, unsigned int);
|
ssize_t (*splice_read)(struct file *, loff_t *, struct pipe_inode_info *, size_t, unsigned int);
|
||||||
|
int (*setlease)(struct file *, long, struct file_lock **);
|
||||||
};
|
};
|
||||||
|
|
||||||
struct inode_operations {
|
struct inode_operations {
|
||||||
|
|
Reference in New Issue