diff --git a/sys/fs/msdosfs/msdosfs_denode.c b/sys/fs/msdosfs/msdosfs_denode.c
--- a/sys/fs/msdosfs/msdosfs_denode.c
+++ b/sys/fs/msdosfs/msdosfs_denode.c
@@ -428,11 +428,12 @@
 	if ((boff = length & pmp->pm_crbomask) != 0) {
 		if (isadir) {
 			bn = cntobn(pmp, eofentry);
-			error = bread(pmp->pm_devvp, bn, pmp->pm_bpcluster,
+			error = breadb(pmp->pm_devvp, bntolbn(pmp, bn), bn, pmp->pm_bpcluster,
 			    NOCRED, &bp);
 		} else {
-			error = bread(DETOV(dep), de_cluster(pmp, length),
-			    pmp->pm_bpcluster, cred, &bp);
+			bn = de_cluster(pmp, length);
+			error = breadb(DETOV(dep), bntolbn(pmp, bn), bn, pmp->pm_bpcluster,
+			    cred, &bp);
 		}
 		if (error) {
 #ifdef MSDOSFS_DEBUG
@@ -503,6 +504,7 @@
 	struct msdosfsmount *pmp = dep->de_pmp;
 	struct vnode *vp = DETOV(dep);
 	struct buf *bp;
+	daddr_t bn;
 	off_t eof_clusteroff;
 	u_long count;
 	int error;
@@ -547,7 +549,8 @@
 	 * actual buffer content which might exist in the tail of the
 	 * already valid cluster.
 	 */
-	error = bread(vp, de_cluster(pmp, dep->de_FileSize), pmp->pm_bpcluster,
+	bn = de_cluster(pmp, dep->de_FileSize);
+	error = breadb(vp, bntolbn(pmp, bn), bn, pmp->pm_bpcluster,
 	    NOCRED, &bp);
 	if (error != 0)
 		goto rewind;
diff --git a/sys/fs/msdosfs/msdosfs_fat.c b/sys/fs/msdosfs/msdosfs_fat.c
--- a/sys/fs/msdosfs/msdosfs_fat.c
+++ b/sys/fs/msdosfs/msdosfs_fat.c
@@ -204,7 +204,8 @@
 		if (bn != bp_bn) {
 			if (bp)
 				brelse(bp);
-			error = bread(pmp->pm_devvp, bn, bsize, NOCRED, &bp);
+			error = breadb(pmp->pm_devvp, bntolbn(pmp, bn), bn, bsize,
+			    NOCRED, &bp);
 			if (error) {
 				return (error);
 			}
@@ -339,8 +340,8 @@
 		for (i = 1; i < pmp->pm_FATs; i++) {
 			fatbn += pmp->pm_FATsecs;
 			/* getblk() never fails */
-			bpn = getblk(pmp->pm_devvp, fatbn, bp->b_bcount,
-			    0, 0, 0);
+			bpn = getblkb(pmp->pm_devvp, bntolbn(pmp, fatbn), fatbn,
+			    bp->b_bcount, 0, 0, 0);
 			memcpy(bpn->b_data, bp->b_data, bp->b_bcount);
 			/* Force the clean bit on in the other copies. */
 			if (cleanfat == 16)
@@ -509,7 +510,8 @@
 
 	byteoffset = FATOFS(pmp, cn);
 	fatblock(pmp, byteoffset, &bn, &bsize, &bo);
-	error = bread(pmp->pm_devvp, bn, bsize, NOCRED, &bp);
+	error = breadb(pmp->pm_devvp, bntolbn(pmp, bn), bn, bsize,
+	    NOCRED, &bp);
 	if (error) {
 		return (error);
 	}
@@ -591,7 +593,8 @@
 	while (count > 0) {
 		byteoffset = FATOFS(pmp, start);
 		fatblock(pmp, byteoffset, &bn, &bsize, &bo);
-		error = bread(pmp->pm_devvp, bn, bsize, NOCRED, &bp);
+		error = breadb(pmp->pm_devvp, bntolbn(pmp, bn), bn, bsize,
+		    NOCRED, &bp);
 		if (error) {
 			return (error);
 		}
@@ -845,7 +848,8 @@
 		if (lbn != bn) {
 			if (bp)
 				updatefats(pmp, bp, lbn);
-			error = bread(pmp->pm_devvp, bn, bsize, NOCRED, &bp);
+			error = breadb(pmp->pm_devvp, bntolbn(pmp, bn), bn, bsize,
+			    NOCRED, &bp);
 			if (error) {
 				MSDOSFS_UNLOCK_MP(pmp);
 				return (error);
@@ -927,7 +931,8 @@
 			if (bp != NULL)
 				brelse(bp);
 			fatblock(pmp, byteoffset, &bn, &bsize, NULL);
-			error = bread(pmp->pm_devvp, bn, bsize, NOCRED, &bp);
+			error = breadb(pmp->pm_devvp, bntolbn(pmp, bn), bn, bsize,
+			    NOCRED, &bp);
 			if (error != 0)
 				return (error);
 		}
@@ -946,8 +951,10 @@
 		if (cn == 0 && readcn != ((pmp->pm_fatmask & 0xffffff00) |
 		    pmp->pm_bpb.bpbMedia)) {
 #ifdef MSDOSFS_DEBUG
-			printf("mountmsdosfs(): Media descriptor in BPB"
-			    "does not match FAT ID\n");
+			printf("mountmsdosfs(): Media descriptor in BPB (%#x) "
+			    "does not match FAT ID (%#lx)\n",
+			    (pmp->pm_fatmask & 0xffffff00) | pmp->pm_bpb.bpbMedia,
+			       readcn);
 #endif
 			brelse(bp);
 			return (EINVAL);
@@ -1076,19 +1083,21 @@
 				/*
 				 * Get the buf header for the new block of the file.
 				 */
-				if (dep->de_Attributes & ATTR_DIRECTORY)
-					bp = getblk(pmp->pm_devvp,
-					    cntobn(pmp, cn++),
+				if (dep->de_Attributes & ATTR_DIRECTORY) {
+					blkno = cntobn(pmp, cn++);
+					bp = getblkb(pmp->pm_devvp,
+					    bntolbn(pmp, blkno), blkno,
 					    pmp->pm_bpcluster, 0, 0, 0);
-				else {
-					bp = getblk(DETOV(dep),
-					    frcn++,
+				} else {
+					blkno = frcn++;
+					bp = getblkb(DETOV(dep),
+					    bntolbn(pmp, blkno), blkno,
 					    pmp->pm_bpcluster, 0, 0, 0);
 					/*
 					 * Do the bmap now, as in msdosfs_write
 					 */
 					if (pcbmap(dep,
-					    bp->b_lblkno,
+					    bp->b_blkno,
 					    &blkno, 0, 0))
 						bp->b_blkno = -1;
 					if (bp->b_blkno == -1)
@@ -1160,7 +1169,8 @@
 	 */
 	byteoffset = FATOFS(pmp, 1);
 	fatblock(pmp, byteoffset, &bn, &bsize, &bo);
-	error = bread(pmp->pm_devvp, bn, bsize, NOCRED, &bp);
+	error = breadb(pmp->pm_devvp, bntolbn(pmp, bn), bn, bsize,
+	    NOCRED, &bp);
 	if (error)
 		return (error);
 
diff --git a/sys/fs/msdosfs/msdosfs_lookup.c b/sys/fs/msdosfs/msdosfs_lookup.c
--- a/sys/fs/msdosfs/msdosfs_lookup.c
+++ b/sys/fs/msdosfs/msdosfs_lookup.c
@@ -253,7 +253,8 @@
 				break;
 			return (error);
 		}
-		error = bread(pmp->pm_devvp, bn, blsize, NOCRED, &bp);
+		error = breadb(pmp->pm_devvp, bntolbn(pmp, bn), bn, blsize,
+		    NOCRED, &bp);
 		if (error) {
 			return (error);
 		}
@@ -678,7 +679,8 @@
 	diroffset = ddep->de_fndoffset;
 	if (dirclust != MSDOSFSROOT)
 		diroffset &= pmp->pm_crbomask;
-	if ((error = bread(pmp->pm_devvp, bn, blsize, NOCRED, &bp)) != 0) {
+	if ((error = breadb(pmp->pm_devvp, bntolbn(pmp, bn), bn, blsize,
+		    NOCRED, &bp)) != 0) {
 		brelse(bp);
 		return error;
 	}
@@ -711,8 +713,8 @@
 				if (error)
 					return error;
 
-				error = bread(pmp->pm_devvp, bn, blsize,
-					      NOCRED, &bp);
+				error = breadb(pmp->pm_devvp, bntolbn(pmp, bn),
+				    bn, blsize, NOCRED, &bp);
 				if (error) {
 					return error;
 				}
@@ -778,7 +780,8 @@
 				return (1);	/* it's empty */
 			return (0);
 		}
-		error = bread(pmp->pm_devvp, bn, blsize, NOCRED, &bp);
+		error = breadb(pmp->pm_devvp, bntolbn(pmp, bn), bn, blsize,
+		    NOCRED, &bp);
 		if (error) {
 			return (0);
 		}
@@ -834,6 +837,7 @@
 doscheckpath(struct denode *source, struct denode *target, daddr_t *wait_scn)
 {
 	daddr_t scn;
+	daddr_t bn;
 	struct msdosfsmount *pmp;
 	struct direntry *ep;
 	struct denode *dep;
@@ -866,7 +870,8 @@
 			break;
 		}
 		scn = dep->de_StartCluster;
-		error = bread(pmp->pm_devvp, cntobn(pmp, scn),
+		bn = cntobn(pmp, scn);
+		error = breadb(pmp->pm_devvp, bntolbn(pmp, bn), bn,
 		    pmp->pm_bpcluster, NOCRED, &bp);
 		if (error != 0)
 			break;
@@ -934,7 +939,8 @@
 	    && de_blk(pmp, diroffset + blsize) > pmp->pm_rootdirsize)
 		blsize = de_bn2off(pmp, pmp->pm_rootdirsize) & pmp->pm_crbomask;
 	bn = detobn(pmp, dirclust, diroffset);
-	if ((error = bread(pmp->pm_devvp, bn, blsize, NOCRED, bpp)) != 0) {
+	if ((error = breadb(pmp->pm_devvp, bntolbn(pmp, bn), bn, blsize,
+		    NOCRED, bpp)) != 0) {
 		brelse(*bpp);
 		*bpp = NULL;
 		return (error);
@@ -991,7 +997,8 @@
 		error = pcbmap(pdep, de_cluster(pmp, offset), &bn, 0, &blsize);
 		if (error)
 			return error;
-		error = bread(pmp->pm_devvp, bn, blsize, NOCRED, &bp);
+		error = breadb(pmp->pm_devvp, bntolbn(pmp, bn), bn, blsize,
+		    NOCRED, &bp);
 		if (error) {
 			return error;
 		}
@@ -1068,7 +1075,8 @@
 					return 0;
 				return error;
 			}
-			error = bread(pmp->pm_devvp, bn, blsize, NOCRED, &bp);
+			error = breadb(pmp->pm_devvp, bntolbn(pmp, bn), bn, blsize,
+			    NOCRED, &bp);
 			if (error) {
 				return error;
 			}
diff --git a/sys/fs/msdosfs/msdosfs_vfsops.c b/sys/fs/msdosfs/msdosfs_vfsops.c
--- a/sys/fs/msdosfs/msdosfs_vfsops.c
+++ b/sys/fs/msdosfs/msdosfs_vfsops.c
@@ -457,7 +457,8 @@
 		printf("rootdir_free: dirclu=%d dirleft=%d readsize=%lu\n",
 		       dirclu, dirleft, readsize);
 #endif
-		if (bread(pmp->pm_devvp, dirclu, readsize, NOCRED, &bp) != 0) {
+		if (breadb(pmp->pm_devvp, bntolbn(pmp, dirclu), dirclu, readsize,
+			NOCRED, &bp) != 0) {
 			printf("rootdir_free: read error\n");
 			if (bp != NULL)
 				brelse(bp);
@@ -757,12 +758,27 @@
 		goto error_exit;
 	}
 
+	/*
+	 * Prevent re-use of the buffer since it has been fetched without offset.
+	 */
+	bp->b_flags |= B_NOCACHE|B_NOREUSE;
+
 	/*
 	 * Release the bootsector buffer.
 	 */
 	brelse(bp);
 	bp = NULL;
 
+	/*
+	 * Calculate sector offset required to align clusters with page boundaries.
+	 */
+	pmp->pm_cacheblockoffs = -pmp->pm_firstcluster % de_off2bn(pmp, PAGE_SIZE);
+//#ifdef MSDOSFS_DEBUG
+	printf("mountmsdosfs(): firstcluster=%lu bpcluster=%lu bnshift=%lu cacheblockoffs=%lu\n",
+	    pmp->pm_firstcluster, pmp->pm_bpcluster, pmp->pm_bnshift, pmp->pm_cacheblockoffs);
+//#endif
+//	pmp->pm_cacheblockoffs = 0;
+
 	/*
 	 * Check the fsinfo sector if we have one.  Silently fix up our
 	 * in-core copy of fp->fsinxtfree if it is unknown (0xffffffff)
@@ -771,8 +787,10 @@
 	 */
 	if (pmp->pm_fsinfo) {
 		struct fsinfo *fp;
+		daddr_t bn;
 
-		if ((error = bread(devvp, pmp->pm_fsinfo, pmp->pm_BytesPerSec,
+		bn = pmp->pm_fsinfo;
+		if ((error = breadb(devvp, bntolbn(pmp, bn), bn, pmp->pm_BytesPerSec,
 		    NOCRED, &bp)) != 0)
 			goto error_exit;
 		fp = (struct fsinfo *)bp->b_data;
@@ -1073,6 +1091,7 @@
 {
 	struct fsinfo *fp;
 	struct buf *bp;
+	daddr_t bn;
 	int error;
 
 	MSDOSFS_LOCK_MP(pmp);
@@ -1080,7 +1099,8 @@
 		error = 0;
 		goto unlock;
 	}
-	error = bread(pmp->pm_devvp, pmp->pm_fsinfo, pmp->pm_BytesPerSec,
+	bn = pmp->pm_fsinfo;
+	error = breadb(pmp->pm_devvp, bntolbn(pmp, bn), bn, pmp->pm_BytesPerSec,
 	    NOCRED, &bp);
 	if (error != 0) {
 		goto unlock;
diff --git a/sys/fs/msdosfs/msdosfs_vnops.c b/sys/fs/msdosfs/msdosfs_vnops.c
--- a/sys/fs/msdosfs/msdosfs_vnops.c
+++ b/sys/fs/msdosfs/msdosfs_vnops.c
@@ -573,18 +573,20 @@
 				break;
 			} else if (error)
 				break;
-			error = bread(pmp->pm_devvp, lbn, blsize, NOCRED, &bp);
+			error = breadb(pmp->pm_devvp, bntolbn(pmp, lbn), lbn, blsize,
+			    NOCRED, &bp);
 		} else if (de_cn2off(pmp, rablock) >= dep->de_FileSize) {
-			error = bread(vp, lbn, blsize, NOCRED, &bp);
-		} else if ((vp->v_mount->mnt_flag & MNT_NOCLUSTERR) == 0) {
+			error = breadb(vp, bntolbn(pmp, lbn), lbn, blsize, NOCRED, &bp);
+		} else if ((vp->v_mount->mnt_flag & MNT_NOCLUSTERR) == 0 &&
+		    pmp->pm_cacheblockoffs == 0) {
 			error = cluster_read(vp, dep->de_FileSize, lbn, blsize,
 			    NOCRED, on + uio->uio_resid, seqcount, 0, &bp);
 		} else if (seqcount > 1) {
 			rasize = blsize;
-			error = breadn(vp, lbn,
+			error = breadbn(vp, bntolbn(pmp, lbn), lbn,
 			    blsize, &rablock, &rasize, 1, NOCRED, &bp);
 		} else {
-			error = bread(vp, lbn, blsize, NOCRED, &bp);
+			error = breadb(vp, bntolbn(pmp, lbn), lbn, blsize, NOCRED, &bp);
 		}
 		if (error) {
 			brelse(bp);
@@ -729,7 +731,8 @@
 			 * or we write the cluster from its start beyond EOF,
 			 * then no need to read data from disk.
 			 */
-			bp = getblk(thisvp, bn, pmp->pm_bpcluster, 0, 0, 0);
+			bp = getblkb(thisvp, bntolbn(pmp, bn), bn, pmp->pm_bpcluster,
+			    0, 0, 0);
 			/*
 			 * This call to vfs_bio_clrbuf() ensures that
 			 * even if vn_io_fault_uiomove() below faults,
@@ -741,8 +744,8 @@
 			 * Do the bmap now, since pcbmap needs buffers
 			 * for the FAT table. (see msdosfs_strategy)
 			 */
-			if (bp->b_blkno == bp->b_lblkno) {
-				error = pcbmap(dep, bp->b_lblkno, &bn, 0, 0);
+			if (bntolbn(pmp, bp->b_blkno) == bp->b_lblkno) { // XXX ???
+				error = pcbmap(dep, bp->b_blkno, &bn, 0, 0);
 				if (error)
 					bp->b_blkno = -1;
 				else
@@ -758,7 +761,8 @@
 			/*
 			 * The block we need to write into exists, so read it in.
 			 */
-			error = bread(thisvp, bn, pmp->pm_bpcluster, cred, &bp);
+			error = breadb(thisvp, bntolbn(pmp, bn), bn, pmp->pm_bpcluster,
+			    cred, &bp);
 			if (error) {
 				break;
 			}
@@ -797,7 +801,8 @@
 		else if (vm_page_count_severe() || buf_dirty_count_severe())
 			bawrite(bp);
 		else if (n + croffset == pmp->pm_bpcluster) {
-			if ((vp->v_mount->mnt_flag & MNT_NOCLUSTERW) == 0)
+			if ((vp->v_mount->mnt_flag & MNT_NOCLUSTERW) == 0 &&
+			    pmp->pm_cacheblockoffs == 0)
 				cluster_write(vp, &dep->de_clusterw, bp,
 				    dep->de_FileSize, seqcount, 0);
 			else
@@ -1237,10 +1242,10 @@
 		if (cn == MSDOSFSROOT) {
 			/* this should never happen */
 			panic("msdosfs_rename(): updating .. in root directory?");
-		} else
-			bn = cntobn(pmp, cn);
-		error = bread(pmp->pm_devvp, bn, pmp->pm_bpcluster,
-		    NOCRED, &bp);
+		}
+		bn = cntobn(pmp, cn);
+		error = breadb(pmp->pm_devvp, bntolbn(pmp, bn), bn,
+		    pmp->pm_bpcluster, NOCRED, &bp);
 		if (error != 0) {
 			printf("%s: block read error %d while renaming dir\n",
 			    pmp->pm_mountp->mnt_stat.f_mntonname,
@@ -1380,7 +1385,8 @@
 	 */
 	bn = cntobn(pmp, newcluster);
 	/* always succeeds */
-	bp = getblk(pmp->pm_devvp, bn, pmp->pm_bpcluster, 0, 0, 0);
+	bp = getblkb(pmp->pm_devvp, bntolbn(pmp, bn), bn, pmp->pm_bpcluster,
+	    0, 0, 0);
 	memset(bp->b_data, 0, pmp->pm_bpcluster);
 	memcpy(bp->b_data, &dosdirtemplate, sizeof dosdirtemplate);
 	denp = (struct direntry *)bp->b_data;
@@ -1629,7 +1635,8 @@
 		error = pcbmap(dep, lbn, &bn, &cn, &blsize);
 		if (error)
 			break;
-		error = bread(pmp->pm_devvp, bn, blsize, NOCRED, &bp);
+		error = breadb(pmp->pm_devvp, bntolbn(pmp, bn), bn, blsize,
+		    NOCRED, &bp);
 		if (error) {
 			return (error);
 		}
diff --git a/sys/fs/msdosfs/msdosfsmount.h b/sys/fs/msdosfs/msdosfsmount.h
--- a/sys/fs/msdosfs/msdosfsmount.h
+++ b/sys/fs/msdosfs/msdosfsmount.h
@@ -91,6 +91,7 @@
 	u_long pm_rootdirblk;	/* block # (cluster # for FAT32) of root directory number */
 	u_long pm_rootdirsize;	/* size in blocks (not clusters) */
 	u_long pm_firstcluster;	/* block number of first cluster */
+	u_long pm_cacheblockoffs;	/* offset from physical block to buffer cache block number */
 	u_long pm_maxcluster;	/* maximum cluster number */
 	u_long pm_freeclustercount;	/* number of free clusters */
 	u_long pm_cnshift;	/* shift file offset right this amount to get a cluster number */
@@ -201,6 +202,13 @@
  */
 #define	de_bn2off(pmp, bn) \
 	((bn) << (pmp)->pm_bnshift)
+
+/*
+ * Convert offset to block number
+ */
+#define	de_off2bn(pmp, off) \
+	((off) >> (pmp)->pm_bnshift)
+
 /*
  * Map a cluster number into a filesystem relative block number.
  */
@@ -213,6 +221,12 @@
 #define	roottobn(pmp, dirofs) \
 	(de_blk((pmp), (dirofs)) + (pmp)->pm_rootdirblk)
 
+/*
+ * Calculate buffer cache block number from disk block number
+ */
+#define	bntolbn(pmp, bn) \
+	((pmp)->pm_cacheblockoffs + (bn))
+
 /*
  * Calculate block number for directory entry at cluster dirclu, offset
  * dirofs
diff --git a/sys/kern/vfs_bio.c b/sys/kern/vfs_bio.c
--- a/sys/kern/vfs_bio.c
+++ b/sys/kern/vfs_bio.c
@@ -3289,7 +3289,7 @@
 		 */
 		if (ncl != 1) {
 			BUF_UNLOCK(bp);
-			nwritten = cluster_wbuild(vp, size, lblkno - j, ncl,
+			nwritten = cluster_wbuild(vp, size, lblkno - j, ncl, // XXX only lblkno used !!!
 			    gbflags);
 			return (nwritten);
 		}
@@ -3914,17 +3914,24 @@
 	}
 }
 
+struct buf *
+getblkb(struct vnode *vp, daddr_t blkno, daddr_t dblkno, int size, int slpflag,
+    int slptimeo, int flags)
+{
+       struct buf *bp;
+       int error;
+
+       error = getblkx(vp, blkno, dblkno, size, slpflag, slptimeo, flags, &bp);
+       if (error != 0)
+               return (NULL);
+       return (bp);
+}
+
 struct buf *
 getblk(struct vnode *vp, daddr_t blkno, int size, int slpflag, int slptimeo,
     int flags)
 {
-	struct buf *bp;
-	int error;
-
-	error = getblkx(vp, blkno, blkno, size, slpflag, slptimeo, flags, &bp);
-	if (error != 0)
-		return (NULL);
-	return (bp);
+	return (getblkb(vp, blkno, blkno, size, slpflag, slptimeo, flags));
 }
 
 /*
diff --git a/sys/sys/buf.h b/sys/sys/buf.h
--- a/sys/sys/buf.h
+++ b/sys/sys/buf.h
@@ -549,12 +549,18 @@
 #define bread(vp, blkno, size, cred, bpp) \
 	    breadn_flags(vp, blkno, blkno, size, NULL, NULL, 0, cred, 0, \
 		NULL, bpp)
+#define breadb(vp, blkno, dblkno, size, cred, bpp) \
+	    breadn_flags(vp, blkno, dblkno, size, NULL, NULL, 0, cred, 0, \
+		NULL, bpp)
 #define bread_gb(vp, blkno, size, cred, gbflags, bpp) \
 	    breadn_flags(vp, blkno, blkno, size, NULL, NULL, 0, cred, \
 		gbflags, NULL, bpp)
 #define breadn(vp, blkno, size, rablkno, rabsize, cnt, cred, bpp) \
 	    breadn_flags(vp, blkno, blkno, size, rablkno, rabsize, cnt, cred, \
 		0, NULL, bpp)
+#define breadbn(vp, blkno, dblkno, size, rablkno, rabsize, cnt, cred, bpp) \
+	    breadn_flags(vp, blkno, dblkno, size, rablkno, rabsize, cnt, cred, \
+		0, NULL, bpp)
 int	breadn_flags(struct vnode *, daddr_t, daddr_t, int, daddr_t *, int *, 
 	    int, struct ucred *, int, void (*)(struct buf *), struct buf **);
 void	bdwrite(struct buf *);
@@ -574,6 +580,7 @@
 struct buf *gbincore(struct bufobj *, daddr_t);
 struct buf *gbincore_unlocked(struct bufobj *, daddr_t);
 struct buf *getblk(struct vnode *, daddr_t, int, int, int, int);
+struct buf *getblkb(struct vnode *, daddr_t, daddr_t, int, int, int, int);
 int	getblkx(struct vnode *vp, daddr_t blkno, daddr_t dblkno, int size,
 	    int slpflag, int slptimeo, int flags, struct buf **bpp);
 struct buf *geteblk(int, int);