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

2 files changed, 0 insertions, 36 deletions

diff --git a/sys/fs/msdosfs/denode.h b/sys/fs/msdosfs/denode.h
index fbd95aa62c8e..4e03e9a6be2f 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) */
 };
 
diff --git a/sys/fs/msdosfs/msdosfs_vnops.c b/sys/fs/msdosfs/msdosfs_vnops.c
index 7a89f7bd8526..8a1484fc06c9 100644
--- a/sys/fs/msdosfs/msdosfs_vnops.c
+++ b/sys/fs/msdosfs/msdosfs_vnops.c
@@ -82,8 +82,6 @@
 /*
  * Prototypes for MSDOSFS vnode operations
  */
-static vop_advlock_t	msdosfs_advlock;
-static vop_advlockasync_t msdosfs_advlockasync;
 static vop_create_t	msdosfs_create;
 static vop_mknod_t	msdosfs_mknod;
 static vop_open_t	msdosfs_open;
@@ -1949,37 +1947,6 @@ msdosfs_pathconf(ap)
 }
 
 static int
-msdosfs_advlock(ap)
-	struct vop_advlock_args /* {
-		struct vnode *a_vp;
-		u_char a_id;
-		int a_op;
-		struct flock *a_fl;
-		int a_flags;
-	} */ *ap;
-{
-	struct denode *dep = VTODE(ap->a_vp);
-
-	return (lf_advlock(ap, &dep->de_lockf, dep->de_FileSize));
-}
-
-static int
-msdosfs_advlockasync(ap)
-	struct vop_advlockasync_args /* {
-		struct vnode *a_vp;
-		u_char a_id;
-		int a_op;
-		struct flock *a_fl;
-		int a_flags;
-		struct task *a_task;
-	} */ *ap;
-{
-	struct denode *dep = VTODE(ap->a_vp);
-
-	return (lf_advlockasync(ap, &dep->de_lockf, dep->de_FileSize));
-}
-
-static int
 msdosfs_vptofh(ap)
 	struct vop_vptofh_args /* {
 		struct vnode *a_vp;
@@ -2003,8 +1970,6 @@ struct vop_vector msdosfs_vnodeops = {
 	.vop_default =		&default_vnodeops,
 
 	.vop_access =		msdosfs_access,
-	.vop_advlock =		msdosfs_advlock,
-	.vop_advlockasync =	msdosfs_advlockasync,
 	.vop_bmap =		msdosfs_bmap,
 	.vop_cachedlookup =	msdosfs_lookup,
 	.vop_open =		msdosfs_open,