VOP_LOCK,

#include <sys/param.h>
#include <sys/lock.h>
#include <sys/vnode.h>

int
VOP_LOCK(struct vnode *vp, int flags);

int
VOP_UNLOCK(struct vnode *vp, int flags);

int
VOP_ISLOCKED(struct vnode *vp);

int
vn_lock(struct vnode *vp, int flags);

These calls are used to serialize access to the file system, such as to prevent two writes to the same file from happening at the same time.

The arguments are:

vp

The vnode being locked or unlocked.

flags

One of the lock request types:

LK_SHARED

Shared lock.

LK_EXCLUSIVE

Exclusive lock.

LK_UPGRADE

Shared-to-exclusive upgrade.

LK_DOWNGRADE

Exclusive-to-shared downgrade.

LK_RELEASE

Release any type of lock.

LK_DRAIN

Wait for all lock activity to end.

The lock type may be or'ed with these lock flags:

LK_NOWAIT

Do not sleep to wait for lock.

LK_SLEEPFAIL

Sleep, then return failure.

LK_CANRECURSE

Allow recursive exclusive lock.

LK_NOWITNESS

Instruct witness(4) to ignore this instance.

The lock type may be or'ed with these control flags:

LK_INTERLOCK

Specify when the caller already has a simple lock (VOP_LOCK() will unlock the simple lock after getting the lock).

LK_RETRY

Retry until locked.

Kernel code should use vn_lock() to lock a vnode rather than calling VOP_LOCK() directly. vn_lock() also does not want a thread specified as argument but it assumes curthread to be used.

Zero is returned on success, otherwise an error is returned.

vnode(9)

This manual page was written by Doug Rabson.