--- fs/nfsclient/nfs_clbio.c.orig	2012-01-24 20:49:20.000000000 -0500
+++ fs/nfsclient/nfs_clbio.c	2012-01-24 20:49:51.000000000 -0500
@@ -480,7 +480,8 @@ ncl_bioread(struct vnode *vp, struct uio
 		/* No caching/ no readaheads. Just read data into the user buffer */
 		return ncl_readrpc(vp, uio, cred);
 
-	biosize = vp->v_mount->mnt_stat.f_iosize;
+	KASSERT(vp->v_bufobj.bo_bsize != 0, ("nfscl bio: bo_bsize == 0"));
+	biosize = vp->v_bufobj.bo_bsize;
 	seqcount = (int)((off_t)(ioflag >> IO_SEQSHIFT) * biosize / BKVASIZE);
 	
 	error = nfs_bioread_check_cons(vp, td, cred);
@@ -960,7 +961,8 @@ flush_and_restart:
 	if (vn_rlimit_fsize(vp, uio, td))
 		return (EFBIG);
 
-	biosize = vp->v_mount->mnt_stat.f_iosize;
+	KASSERT(vp->v_bufobj.bo_bsize != 0, ("nfscl bio: bo_bsize == 0"));
+	biosize = vp->v_bufobj.bo_bsize;
 	/*
 	 * Find all of this file's B_NEEDCOMMIT buffers.  If our writes
 	 * would exceed the local maximum per-file write commit size when
@@ -1267,7 +1269,9 @@ nfs_getcacheblk(struct vnode *vp, daddr_
 	if (vp->v_type == VREG) {
 		int biosize;
 
-		biosize = mp->mnt_stat.f_iosize;
+		KASSERT(vp->v_bufobj.bo_bsize != 0,
+		    ("nfscl bio: bo_bsize == 0"));
+		biosize = vp->v_bufobj.bo_bsize;
 		bp->b_blkno = bn * (biosize / DEV_BSIZE);
 	}
 	return (bp);
@@ -1785,9 +1789,11 @@ ncl_meta_setsize(struct vnode *vp, struc
 {
 	struct nfsnode *np = VTONFS(vp);
 	u_quad_t tsize;
-	int biosize = vp->v_mount->mnt_stat.f_iosize;
+	int biosize;
 	int error = 0;
 
+	KASSERT(vp->v_bufobj.bo_bsize != 0, ("nfscl bio: bo_bsize == 0"));
+	biosize = vp->v_bufobj.bo_bsize;
 	mtx_lock(&np->n_mtx);
 	tsize = np->n_size;
 	np->n_size = nsize;
--- nfsclient/nfs_bio.c.orig	2012-01-24 20:50:36.000000000 -0500
+++ nfsclient/nfs_bio.c	2012-01-24 20:52:09.000000000 -0500
@@ -474,7 +474,7 @@ nfs_bioread(struct vnode *vp, struct uio
 		/* No caching/ no readaheads. Just read data into the user buffer */
 		return nfs_readrpc(vp, uio, cred);
 
-	biosize = vp->v_mount->mnt_stat.f_iosize;
+	biosize = vp->v_bufobj.bo_bsize;
 	seqcount = (int)((off_t)(ioflag >> IO_SEQSHIFT) * biosize / BKVASIZE);
 	
 	error = nfs_bioread_check_cons(vp, td, cred);
@@ -951,7 +951,7 @@ flush_and_restart:
 	if (vn_rlimit_fsize(vp, uio, td))
 		return (EFBIG);
 
-	biosize = vp->v_mount->mnt_stat.f_iosize;
+	biosize = vp->v_bufobj.bo_bsize;
 	/*
 	 * Find all of this file's B_NEEDCOMMIT buffers.  If our writes
 	 * would exceed the local maximum per-file write commit size when
@@ -1258,7 +1258,7 @@ nfs_getcacheblk(struct vnode *vp, daddr_
 	if (vp->v_type == VREG) {
 		int biosize;
 
-		biosize = mp->mnt_stat.f_iosize;
+		biosize = vp->v_bufobj.bo_bsize;
 		bp->b_blkno = bn * (biosize / DEV_BSIZE);
 	}
 	return (bp);
@@ -1767,7 +1767,7 @@ nfs_meta_setsize(struct vnode *vp, struc
 {
 	struct nfsnode *np = VTONFS(vp);
 	u_quad_t tsize;
-	int biosize = vp->v_mount->mnt_stat.f_iosize;
+	int biosize = vp->v_bufobj.bo_bsize;
 	int error = 0;
 
 	mtx_lock(&np->n_mtx);