This patch removes the VOP_BWRITE() vector.

VOP_BWRITE() was a hack which made it possible for NFS client
side to use struct buf with non-bio backing.

This patch takes a more general approach and adds a bp->b_op
vector where more methods can be added.

The success of this patch depends on bp->b_op being initialized
all relevant places for some value of "relevant" which is not
easy to determine.  For now the buffers have grown a b_magic
element which will make such issues a tiny bit easier to debug.

2 files changed, 23 insertions, 19 deletions

diff --git a/sys/nfs/nfs_bio.c b/sys/nfs/nfs_bio.c
index 0c30ca3..442af96 100644
--- a/sys/nfs/nfs_bio.c
+++ b/sys/nfs/nfs_bio.c
@@ -63,6 +63,23 @@
 #include <nfs/nqnfs.h>
 #include <nfs/nfsnode.h>
 
+/*
+ * Just call nfs_writebp() with the force argument set to 1.
+ *
+ * NOTE: B_DONE may or may not be set in a_bp on call.
+ */
+static int
+nfs_bwrite(struct buf *bp)
+{
+	return (nfs_writebp(bp, 1, curproc));
+}
+
+struct buf_ops buf_ops_nfs = {
+	"buf_ops_nfs",
+	nfs_bwrite
+};
+
+
 static struct buf *nfs_getcacheblk __P((struct vnode *vp, daddr_t bn, int size,
 					struct proc *p));
 
@@ -890,6 +907,8 @@ again:
 				bcount += n;
 				allocbuf(bp, bcount);
 				bp->b_flags |= save;
+				bp->b_magic = B_MAGIC_NFS;
+				bp->b_op = &buf_ops_nfs;
 			}
 		} else {
 			/*
diff --git a/sys/nfs/nfs_vnops.c b/sys/nfs/nfs_vnops.c
index d889cf4..2a5564e 100644
--- a/sys/nfs/nfs_vnops.c
+++ b/sys/nfs/nfs_vnops.c
@@ -129,7 +129,6 @@ static int	nfsspec_access __P((struct vop_access_args *));
 static int	nfs_readlink __P((struct vop_readlink_args *));
 static int	nfs_print __P((struct vop_print_args *));
 static int	nfs_advlock __P((struct vop_advlock_args *));
-static int	nfs_bwrite __P((struct vop_bwrite_args *));
 /*
  * Global vfs data structures for nfs
  */
@@ -139,7 +138,6 @@ static struct vnodeopv_entry_desc nfsv2_vnodeop_entries[] = {
 	{ &vop_access_desc,		(vop_t *) nfs_access },
 	{ &vop_advlock_desc,		(vop_t *) nfs_advlock },
 	{ &vop_bmap_desc,		(vop_t *) nfs_bmap },
-	{ &vop_bwrite_desc,		(vop_t *) nfs_bwrite },
 	{ &vop_close_desc,		(vop_t *) nfs_close },
 	{ &vop_create_desc,		(vop_t *) nfs_create },
 	{ &vop_fsync_desc,		(vop_t *) nfs_fsync },
@@ -3090,23 +3088,10 @@ nfs_print(ap)
 }
 
 /*
- * Just call nfs_writebp() with the force argument set to 1.
- *
- * NOTE: B_DONE may or may not be set in a_bp on call.
- */
-static int
-nfs_bwrite(ap)
-	struct vop_bwrite_args /* {
-		struct vnode *a_bp;
-	} */ *ap;
-{
-	return (nfs_writebp(ap->a_bp, 1, curproc));
-}
-
-/*
- * This is a clone of vn_bwrite(), except that B_WRITEINPROG isn't set unless
- * the force flag is one and it also handles the B_NEEDCOMMIT flag.  We set
- * B_CACHE if this is a VMIO buffer.
+ * This is the "real" nfs::bwrite(struct buf*).
+ * B_WRITEINPROG isn't set unless the force flag is one and it 
+ * handles the B_NEEDCOMMIT flag.
+ * We set B_CACHE if this is a VMIO buffer.
  */
 int
 nfs_writebp(bp, force, procp)