diff --git a/lib/libufs/Makefile b/lib/libufs/Makefile
--- a/lib/libufs/Makefile
+++ b/lib/libufs/Makefile
@@ -2,7 +2,7 @@
 PACKAGE=	ufs
 LIB=	ufs
 SHLIBDIR?= /lib
-SHLIB_MAJOR=	7
+SHLIB_MAJOR=	8
 
 SRCS=	block.c cgroup.c gsb_crc32.c inode.c sblock.c type.c ffs_subr.c
 SRCS+= ffs_tables.c
diff --git a/lib/libufs/block.c b/lib/libufs/block.c
--- a/lib/libufs/block.c
+++ b/lib/libufs/block.c
@@ -57,19 +57,10 @@
 
 	ERROR(disk, NULL);
 
-	p2 = data;
-	/*
-	 * XXX: various disk controllers require alignment of our buffer
-	 * XXX: which is stricter than struct alignment.
-	 * XXX: Bounce the buffer if not 64 byte aligned.
-	 * XXX: this can be removed if/when the kernel is fixed
-	 */
-	if (((intptr_t)data) & 0x3f) {
-		p2 = malloc(size);
-		if (p2 == NULL) {
-			ERROR(disk, "allocate bounce buffer");
-			goto fail;
-		}
+	BUF_MALLOC(&p2, data, size);
+	if (p2 == NULL) {
+		ERROR(disk, "allocate bounce buffer");
+		goto fail;
 	}
 	cnt = pread(disk->d_fd, p2, size, (off_t)(blockno * disk->d_bsize));
 	if (cnt == -1) {
@@ -101,7 +92,7 @@
 {
 	ssize_t cnt;
 	int rv;
-	void *p2 = NULL;
+	void *p2;
 
 	ERROR(disk, NULL);
 
@@ -110,24 +101,15 @@
 		ERROR(disk, "failed to open disk for writing");
 		return (-1);
 	}
-
-	/*
-	 * XXX: various disk controllers require alignment of our buffer
-	 * XXX: which is stricter than struct alignment.
-	 * XXX: Bounce the buffer if not 64 byte aligned.
-	 * XXX: this can be removed if/when the kernel is fixed
-	 */
-	if (((intptr_t)data) & 0x3f) {
-		p2 = malloc(size);
-		if (p2 == NULL) {
-			ERROR(disk, "allocate bounce buffer");
-			return (-1);
-		}
-		memcpy(p2, data, size);
-		data = p2;
+	BUF_MALLOC(&p2, data, size);
+	if (p2 == NULL) {
+		ERROR(disk, "allocate bounce buffer");
+		return (-1);
 	}
-	cnt = pwrite(disk->d_fd, data, size, (off_t)(blockno * disk->d_bsize));
-	if (p2 != NULL)
+	if (p2 != data)
+		memcpy(p2, data, size);
+	cnt = pwrite(disk->d_fd, p2, size, (off_t)(blockno * disk->d_bsize));
+	if (p2 != data)
 		free(p2);
 	if (cnt == -1) {
 		ERROR(disk, "write error to block device");
@@ -137,7 +119,6 @@
 		ERROR(disk, "short write to block device");
 		return (-1);
 	}
-
 	return (cnt);
 }
 
diff --git a/lib/libufs/inode.c b/lib/libufs/inode.c
--- a/lib/libufs/inode.c
+++ b/lib/libufs/inode.c
@@ -62,18 +62,10 @@
 		ERROR(disk, "inode number out of range");
 		return (-1);
 	}
-	inoblock = disk->d_inoblock;
+	inoblock = (caddr_t)&disk->d_inos[0];
 	min = disk->d_inomin;
 	max = disk->d_inomax;
 
-	if (inoblock == NULL) {
-		inoblock = malloc(fs->fs_bsize);
-		if (inoblock == NULL) {
-			ERROR(disk, "unable to allocate inode block");
-			return (-1);
-		}
-		disk->d_inoblock = inoblock;
-	}
 	if (inum >= min && inum < max)
 		goto gotit;
 	bread(disk, fsbtodb(fs, ino_to_fsba(fs, inum)), inoblock,
@@ -107,14 +99,10 @@
 	struct fs *fs;
 
 	fs = &disk->d_fs;
-	if (disk->d_inoblock == NULL) {
-		ERROR(disk, "No inode block allocated");
-		return (-1);
-	}
 	if (disk->d_ufs == 2)
 		ffs_update_dinode_ckhash(fs, disk->d_dp.dp2);
 	if (bwrite(disk, fsbtodb(fs, ino_to_fsba(&disk->d_fs, disk->d_inomin)),
-	    disk->d_inoblock, disk->d_fs.fs_bsize) <= 0)
+	    (caddr_t)&disk->d_inos[0], disk->d_fs.fs_bsize) <= 0)
 		return (-1);
 	return (0);
 }
diff --git a/lib/libufs/libufs.h b/lib/libufs/libufs.h
--- a/lib/libufs/libufs.h
+++ b/lib/libufs/libufs.h
@@ -30,6 +30,15 @@
 #ifndef	__LIBUFS_H__
 #define	__LIBUFS_H__
 
+/*
+ * Various disk controllers require their buffers to be aligned to the size
+ * of a cache line. The LIBUFS_BUFALIGN defines the required alignment size.
+ * The alignment must be a power of 2.
+ */
+#define LIBUFS_BUFALIGN	64
+_Static_assert(powerof2(LIBUFS_BUFALIGN),
+    "LIBUFS_BUFALIGN must be a power of 2");
+
 /*
  * libufs structures.
  */
@@ -48,26 +57,29 @@
 	long d_bsize;			/* device bsize */
 	ufs2_daddr_t d_sblock;		/* superblock location */
 	struct fs_summary_info *d_si;	/* Superblock summary info */
-	caddr_t d_inoblock;		/* inode block */
 	uint32_t d_inomin;		/* low ino, not ino_t for ABI compat */
 	uint32_t d_inomax;		/* high ino, not ino_t for ABI compat */
 	union dinodep d_dp;		/* pointer to currently active inode */
-	union {
-		struct fs d_fs;		/* filesystem information */
-		char d_sb[MAXBSIZE];	/* superblock as buffer */
-	} d_sbunion;
-	union {
-		struct cg d_cg;		/* cylinder group */
-		char d_buf[MAXBSIZE];	/* cylinder group storage */
-	} d_cgunion;
 	int d_ccg;			/* current cylinder group */
 	int d_lcg;			/* last cylinder group (in d_cg) */
 	const char *d_error;		/* human readable disk error */
 	off_t d_sblockloc;		/* where to look for the superblock */
 	int d_lookupflags;		/* flags to superblock lookup */
 	int d_mine;			/* internal flags */
+	union {
+		struct fs d_fs;		/* filesystem information */
+		char d_sb[SBLOCKSIZE];	/* superblock as buffer */
+	} d_sbunion __aligned(LIBUFS_BUFALIGN);
+	union {
+		struct cg d_cg;		/* cylinder group */
+		char d_buf[MAXBSIZE];	/* cylinder group storage */
+	} d_cgunion __aligned(LIBUFS_BUFALIGN);
+	union {
+		union dinodep d_ino[1];	/* inode block */
+		char d_inos[MAXBSIZE];	/* inode block as buffer */
+	} d_inosunion __aligned(LIBUFS_BUFALIGN);
+#define	d_inos	d_inosunion.d_inos
 #define	d_fs	d_sbunion.d_fs
-#define	d_sb	d_sbunion.d_sb
 #define	d_cg	d_cgunion.d_cg
 };
 
@@ -75,6 +87,15 @@
  * libufs macros (internal, non-exported).
  */
 #ifdef	_LIBUFS
+/*
+ * Ensure that the buffer is aligned to the I/O subsystem requirements.
+ */
+#define BUF_MALLOC(newbufpp, data, size) {				     \
+	if (data != NULL && (((intptr_t)data) & (LIBUFS_BUFALIGN - 1)) == 0) \
+		*newbufpp = (void *)data;				     \
+	else								     \
+		*newbufpp = aligned_alloc(LIBUFS_BUFALIGN, size);	     \
+}
 /*
  * Trace steps through libufs, to be used at entry and erroneous return.
  */
diff --git a/lib/libufs/sblock.c b/lib/libufs/sblock.c
--- a/lib/libufs/sblock.c
+++ b/lib/libufs/sblock.c
@@ -228,7 +228,8 @@
 	int fd;
 
 	fd = *(int *)devfd;
-	if ((*bufp = malloc(size)) == NULL)
+	BUF_MALLOC(bufp, NULL, size);
+	if (*bufp == NULL)
 		return (ENOSPC);
 	if (pread(fd, *bufp, size, loc) != size)
 		return (EIO);
diff --git a/lib/libufs/type.c b/lib/libufs/type.c
--- a/lib/libufs/type.c
+++ b/lib/libufs/type.c
@@ -61,10 +61,6 @@
 	ERROR(disk, NULL);
 	close(disk->d_fd);
 	disk->d_fd = -1;
-	if (disk->d_inoblock != NULL) {
-		free(disk->d_inoblock);
-		disk->d_inoblock = NULL;
-	}
 	if (disk->d_mine & MINE_NAME) {
 		free((char *)(uintptr_t)disk->d_name);
 		disk->d_name = NULL;
@@ -158,7 +154,6 @@
 	disk->d_bsize = 1;
 	disk->d_ccg = 0;
 	disk->d_fd = fd;
-	disk->d_inoblock = NULL;
 	disk->d_inomin = 0;
 	disk->d_inomax = 0;
 	disk->d_lcg = 0;