===========================================================================
xfsprogs/include/libxfs.h
===========================================================================

--- a/xfsprogs/include/libxfs.h	2008-05-30 11:00:44.000000000 +1000
+++ b/xfsprogs/include/libxfs.h	2008-05-30 10:55:15.561596557 +1000
@@ -69,11 +69,14 @@ typedef struct {
 	char            *rtname;        /* pathname of realtime "subvolume" */
 	int             isreadonly;     /* filesystem is only read in applic */
 	int             isdirect;       /* we can attempt to use direct I/O */
-	int             disfile;        /* data "subvolume" is a regular file */        int             dcreat;         /* try to create data subvolume */
+	int             disfile;        /* data "subvolume" is a regular file */
+	int             dcreat;         /* try to create data subvolume */
 	int             lisfile;        /* log "subvolume" is a regular file */
 	int             lcreat;         /* try to create log subvolume */
-	int             risfile;        /* realtime "subvolume" is a reg file */        int             rcreat;         /* try to create realtime subvolume */
+	int             risfile;        /* realtime "subvolume" is a reg file */
+	int             rcreat;         /* try to create realtime subvolume */
 	int		setblksize;	/* attempt to set device blksize */
+	int		usebuflock;	/* lock xfs_buf_t's - for MT usage */
 				/* output results */
 	dev_t           ddev;           /* device for data subvolume */
 	dev_t           logdev;         /* device for log subvolume */

===========================================================================
xfsprogs/libxfs/init.c
===========================================================================

--- a/xfsprogs/libxfs/init.c	2008-05-30 11:00:44.000000000 +1000
+++ b/xfsprogs/libxfs/init.c	2008-05-30 10:57:52.189289029 +1000
@@ -28,6 +28,8 @@ int libxfs_ihash_size;		/* #buckets in i
 struct cache *libxfs_bcache;	/* global buffer cache */
 int libxfs_bhash_size;		/* #buckets in bcache */
 
+int	use_xfs_buf_lock;	/* global flag: use xfs_buf_t locks for MT */
+
 static void manage_zones(int);	/* setup global zones */
 
 /*
@@ -335,6 +337,7 @@ libxfs_init(libxfs_init_t *a)
 	if (!libxfs_bhash_size)
 		libxfs_bhash_size = LIBXFS_BHASHSIZE(sbp);
 	libxfs_bcache = cache_init(libxfs_bhash_size, &libxfs_bcache_operations);
+	use_xfs_buf_lock = a->usebuflock;
 	manage_zones(0);
 	rval = 1;
 done:

===========================================================================
xfsprogs/libxfs/rdwr.c
===========================================================================

--- a/xfsprogs/libxfs/rdwr.c	2008-05-30 11:00:44.000000000 +1000
+++ b/xfsprogs/libxfs/rdwr.c	2008-05-30 10:58:47.018181515 +1000
@@ -375,6 +375,8 @@ struct list_head	lock_buf_list = {&lock_
 int			lock_buf_count = 0;
 #endif
 
+extern int     use_xfs_buf_lock;
+
 xfs_buf_t *
 libxfs_getbuf(dev_t device, xfs_daddr_t blkno, int len)
 {
@@ -388,7 +390,8 @@ libxfs_getbuf(dev_t device, xfs_daddr_t 
 
 	miss = cache_node_get(libxfs_bcache, &key, (struct cache_node **)&bp);
 	if (bp) {
-		pthread_mutex_lock(&bp->b_lock);
+		if (use_xfs_buf_lock)
+			pthread_mutex_lock(&bp->b_lock);
 		cache_node_set_priority(libxfs_bcache, (struct cache_node *)bp,
 			cache_node_get_priority((struct cache_node *)bp) - 4);
 #ifdef XFS_BUF_TRACING
@@ -417,7 +420,8 @@ libxfs_putbuf(xfs_buf_t *bp)
 	list_del_init(&bp->b_lock_list);
 	pthread_mutex_unlock(&libxfs_bcache->c_mutex);
 #endif
-	pthread_mutex_unlock(&bp->b_lock);
+	if (use_xfs_buf_lock)
+		pthread_mutex_unlock(&bp->b_lock);
 	cache_node_put((struct cache_node *)bp);
 }
 

===========================================================================
xfsprogs/repair/init.c
===========================================================================

--- a/xfsprogs/repair/init.c	2008-05-30 11:00:44.000000000 +1000
+++ b/xfsprogs/repair/init.c	2008-05-30 10:59:50.217989698 +1000
@@ -135,6 +135,7 @@ xfs_init(libxfs_init_t *args)
 		/* XXX assume data file also means rt file */
 	}
 
+	args->usebuflock = do_prefetch;
 	args->setblksize = !dangerously;
 	args->isdirect = LIBXFS_DIRECT;
 	if (no_modify)