Move the head of byte-level advisory lock list from the

filesystem-specific vnode data to the struct vnode. Provide the
default implementation for the vop_advlock and vop_advlockasync.
Purge the locks on the vnode reclaim by using the lf_purgelocks().
The default implementation is augmented for the nfs and smbfs.
In the nfs_advlock, push the Giant inside the nfs_dolock.

Before the change, the vop_advlock and vop_advlockasync have taken the
unlocked vnode and dereferenced the fs-private inode data, racing with
with the vnode reclamation due to forced unmount. Now, the vop_getattr
under the shared vnode lock is used to obtain the inode size, and
later, in the lf_advlockasync, after locking the vnode interlock, the
VI_DOOMED flag is checked to prevent an operation on the doomed vnode.

The implementation of the lf_purgelocks() is submitted by dfr.

Reported by:	kris
Tested by:	kris, pho
Discussed with:	jeff, dfr
MFC after:	2 weeks

1 files changed, 0 insertions, 1 deletions

diff --git a/sys/fs/msdosfs/denode.h b/sys/fs/msdosfs/denode.h
index fbd95aa..4e03e9a 100644
--- a/sys/fs/msdosfs/denode.h
+++ b/sys/fs/msdosfs/denode.h
@@ -159,7 +159,6 @@ struct denode {
 	u_long de_FileSize;	/* size of file in bytes */
 	struct fatcache de_fc[FC_SIZE];	/* fat cache */
 	u_quad_t de_modrev;	/* Revision level for lease. */
-	struct lockf *de_lockf; /* lockf */
 	u_int64_t de_inode;	/* Inode number (really byte offset of direntry) */
 };