diff --git sbin/tunefs/tunefs.c sbin/tunefs/tunefs.c
index 08c127d..aee33fb 100644
--- sbin/tunefs/tunefs.c
+++ sbin/tunefs/tunefs.c
@@ -688,6 +688,19 @@ journal_findfile(void)
 	return (0);
 }
 
+static void
+dir_clear_block(char *block, off_t off)
+{
+	struct direct *dp;
+
+	for (; off < sblock.fs_bsize; off += DIRBLKSIZ) {
+		dp = (struct direct *)&block[off];
+		dp->d_ino = 0;
+		dp->d_reclen = DIRBLKSIZ;
+		dp->d_type = DT_UNKNOWN;
+	}
+}
+
 /*
  * Insert the journal at inode 'ino' into directory blk 'blk' at the first
  * free offset of 'off'.  DIRBLKSIZ blocks after off are initialized as
@@ -710,13 +723,7 @@ dir_insert(ufs2_daddr_t blk, off_t off, ino_t ino)
 	dp->d_type = DT_REG;
 	dp->d_namlen = strlen(SUJ_FILE);
 	bcopy(SUJ_FILE, &dp->d_name, strlen(SUJ_FILE));
-	off += DIRBLKSIZ;
-	for (; off < sblock.fs_bsize; off += DIRBLKSIZ) {
-		dp = (struct direct *)&block[off];
-		dp->d_ino = 0;
-		dp->d_reclen = DIRBLKSIZ;
-		dp->d_type = DT_UNKNOWN;
-	}
+	dir_clear_block(block, off + DIRBLKSIZ);
 	if (bwrite(&disk, fsbtodb(&sblock, blk), block, sblock.fs_bsize) <= 0) {
 		warn("Failed to write dir block");
 		return (-1);
@@ -733,16 +740,19 @@ dir_extend(ufs2_daddr_t blk, ufs2_daddr_t nblk, off_t size, ino_t ino)
 {
 	char block[MAXBSIZE];
 
-	if (bread(&disk, fsbtodb(&sblock, blk), block, size) <= 0) {
+	if (bread(&disk, fsbtodb(&sblock, blk), block,
+	    roundup(size, sblock.fs_fsize)) <= 0) {
 		warn("Failed to read dir block");
 		return (-1);
 	}
-	if (bwrite(&disk, fsbtodb(&sblock, nblk), block, size) <= 0) {
+	dir_clear_block(block, size);
+	if (bwrite(&disk, fsbtodb(&sblock, nblk), block, sblock.fs_bsize)
+	    <= 0) {
 		warn("Failed to write dir block");
 		return (-1);
 	}
 
-	return dir_insert(nblk, size, ino);
+	return (dir_insert(nblk, size, ino));
 }
 
 /*
diff --git sys/ufs/ffs/ffs_softdep.c sys/ufs/ffs/ffs_softdep.c
index 60d4600..6373dcf 100644
--- sys/ufs/ffs/ffs_softdep.c
+++ sys/ufs/ffs/ffs_softdep.c
@@ -747,7 +747,7 @@ static	void handle_written_jnewblk(struct jnewblk *);
 static	void handle_written_jfreeblk(struct jfreeblk *);
 static	void handle_written_jfreefrag(struct jfreefrag *);
 static	void complete_jseg(struct jseg *);
-static	void jseg_write(struct fs *, struct jblocks *, struct jseg *,
+static	void jseg_write(struct ufsmount *ump, struct jblocks *, struct jseg *,
 	    uint8_t *);
 static	void jaddref_write(struct jaddref *, struct jseg *, uint8_t *);
 static	void jremref_write(struct jremref *, struct jseg *, uint8_t *);
@@ -886,7 +886,8 @@ static	void handle_jwork(struct workhead *);
 static	struct mkdir *setup_newdir(struct diradd *, ino_t, ino_t, struct buf *,
 	    struct mkdir **);
 static	struct jblocks *jblocks_create(void);
-static	ufs2_daddr_t jblocks_alloc(struct jblocks *, int, int *);
+static	ufs2_daddr_t jblocks_alloc(struct ufsmount *, struct jblocks *, int,
+	    int *);
 static	void jblocks_free(struct jblocks *, struct mount *, int);
 static	void jblocks_destroy(struct jblocks *);
 static	void jblocks_add(struct jblocks *, ufs2_daddr_t, int);
@@ -2135,7 +2136,8 @@ jblocks_create(void)
 }
 
 static ufs2_daddr_t
-jblocks_alloc(jblocks, bytes, actual)
+jblocks_alloc(ump, jblocks, bytes, actual)
+	struct ufsmount *ump;
 	struct jblocks *jblocks;
 	int bytes;
 	int *actual;
@@ -2145,7 +2147,7 @@ jblocks_alloc(jblocks, bytes, actual)
 	int freecnt;
 	int blocks;
 
-	blocks = bytes / DEV_BSIZE;
+	blocks = bytes / ump->um_devvp->v_bufobj.bo_bsize;
 	jext = &jblocks->jb_extent[jblocks->jb_head];
 	freecnt = jext->je_blocks - jblocks->jb_off;
 	if (freecnt == 0) {
@@ -2157,7 +2159,7 @@ jblocks_alloc(jblocks, bytes, actual)
 	}
 	if (freecnt > blocks)
 		freecnt = blocks;
-	*actual = freecnt * DEV_BSIZE;
+	*actual = freecnt * ump->um_devvp->v_bufobj.bo_bsize;
 	daddr = jext->je_daddr + jblocks->jb_off;
 	jblocks->jb_off += freecnt;
 	jblocks->jb_free -= freecnt;
@@ -2172,7 +2174,7 @@ jblocks_free(jblocks, mp, bytes)
 	int bytes;
 {
 
-	jblocks->jb_free += bytes / DEV_BSIZE;
+	jblocks->jb_free += bytes / VFSTOUFS(mp)->um_devvp->v_bufobj.bo_bsize;
 	if (jblocks->jb_suspended)
 		worklist_speedup();
 	wakeup(jblocks);
@@ -2422,7 +2424,8 @@ journal_space(ump, thresh)
 		thresh = jblocks->jb_min;
 	else
 		thresh = jblocks->jb_low;
-	avail = (ump->softdep_on_journal * JREC_SIZE) / DEV_BSIZE;
+	avail = (ump->softdep_on_journal * JREC_SIZE) /
+	    ump->um_devvp->v_bufobj.bo_bsize;
 	avail = jblocks->jb_free - avail;
 
 	return (avail > thresh);
@@ -2555,8 +2558,8 @@ softdep_prelink(dvp, vp)
 }
 
 static void
-jseg_write(fs, jblocks, jseg, data)
-	struct fs *fs;
+jseg_write(ump, jblocks, jseg, data)
+	struct ufsmount *ump;
 	struct jblocks *jblocks;
 	struct jseg *jseg;
 	uint8_t *data;
@@ -2567,9 +2570,9 @@ jseg_write(fs, jblocks, jseg, data)
 	rec->jsr_seq = jseg->js_seq;
 	rec->jsr_oldest = jblocks->jb_oldestseq;
 	rec->jsr_cnt = jseg->js_cnt;
-	rec->jsr_blocks = jseg->js_size / DEV_BSIZE;
+	rec->jsr_blocks = jseg->js_size / ump->um_devvp->v_bufobj.bo_bsize;
 	rec->jsr_crc = 0;
-	rec->jsr_time = fs->fs_mtime;
+	rec->jsr_time = ump->um_fs->fs_mtime;
 }
 
 static inline void
@@ -2719,19 +2722,21 @@ softdep_process_journal(mp, flags)
 	int size;
 	int cnt;
 	int off;
+	int devbsize;
 
 	if ((mp->mnt_kern_flag & MNTK_SUJ) == 0)
 		return;
 	ump = VFSTOUFS(mp);
 	fs = ump->um_fs;
 	jblocks = ump->softdep_jblocks;
+	devbsize = ump->um_devvp->v_bufobj.bo_bsize;
 	/*
 	 * We write anywhere between a disk block and fs block.  The upper
 	 * bound is picked to prevent buffer cache fragmentation and limit
 	 * processing time per I/O.
 	 */
-	jrecmin = (DEV_BSIZE / JREC_SIZE) - 1; /* -1 for seg header */
-	jrecmax = (fs->fs_bsize / DEV_BSIZE) * jrecmin;
+	jrecmin = (devbsize / JREC_SIZE) - 1; /* -1 for seg header */
+	jrecmax = (fs->fs_bsize / devbsize) * jrecmin;
 	segwritten = 0;
 	while ((cnt = ump->softdep_on_journal) != 0) {
 		/*
@@ -2786,7 +2791,7 @@ softdep_process_journal(mp, flags)
 		 */
 		cnt = ump->softdep_on_journal;
 		if (cnt < jrecmax)
-			size = howmany(cnt, jrecmin) * DEV_BSIZE;
+			size = howmany(cnt, jrecmin) * devbsize;
 		else
 			size = fs->fs_bsize;
 		/*
@@ -2794,9 +2799,10 @@ softdep_process_journal(mp, flags)
 		 * for truncation of the requested size if enough contiguous
 		 * space was not available.
 		 */
-		bp->b_blkno = jblocks_alloc(jblocks, size, &size);
+		bp->b_blkno = jblocks_alloc(ump, jblocks, size, &size) *
+		    btodb(devbsize);
 		bp->b_lblkno = bp->b_blkno;
-		bp->b_offset = bp->b_blkno * DEV_BSIZE;
+		bp->b_offset = bp->b_blkno * devbsize;
 		bp->b_bcount = size;
 		bp->b_bufobj = &ump->um_devvp->v_bufobj;
 		bp->b_flags &= ~B_INVAL;
@@ -2806,7 +2812,7 @@ softdep_process_journal(mp, flags)
 		 * sequence number to it and link it in-order.
 		 */
 		cnt = MIN(ump->softdep_on_journal,
-		    (size / DEV_BSIZE) * jrecmin);
+		    (size / devbsize) * jrecmin);
 		jseg->js_buf = bp;
 		jseg->js_cnt = cnt;
 		jseg->js_refs = cnt + 1;	/* Self ref. */
@@ -2825,8 +2831,8 @@ softdep_process_journal(mp, flags)
 		while ((wk = LIST_FIRST(&ump->softdep_journal_pending))
 		    != NULL) {
 			/* Place a segment header on every device block. */
-			if ((off % DEV_BSIZE) == 0) {
-				jseg_write(fs, jblocks, jseg, data);
+			if ((off % devbsize) == 0) {
+				jseg_write(ump, jblocks, jseg, data);
 				off += JREC_SIZE;
 				data = bp->b_data + off;
 			}