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
@@ -4003,7 +4003,10 @@
 		 * it must be on a queue.
 		 */
 		lockflags = LK_EXCLUSIVE | LK_INTERLOCK |
-		    ((flags & GB_LOCK_NOWAIT) ? LK_NOWAIT : LK_SLEEPFAIL);
+		    ((flags & GB_LOCK_NOWAIT) != 0 ? LK_NOWAIT : LK_SLEEPFAIL);
+#ifdef WITNESS
+		lockflags |= (flags & GB_NOWITNESS) != 0 ? LK_NOWITNESS : 0;
+#endif
 
 		error = BUF_TIMELOCK(bp, lockflags,
 		    BO_LOCKPTR(bo), "getblk", slpflag, slptimeo);
diff --git a/sys/sys/buf.h b/sys/sys/buf.h
--- a/sys/sys/buf.h
+++ b/sys/sys/buf.h
@@ -508,6 +508,7 @@
 #define	GB_CKHASH	0x0020		/* If reading, calc checksum hash */
 #define	GB_NOSPARSE	0x0040		/* Do not instantiate holes */
 #define	GB_CVTENXIO	0x0080		/* Convert errors to ENXIO */
+#define	GB_NOWITNESS	0x0100		/* Do not record for WITNESS */
 
 #ifdef _KERNEL
 extern int	nbuf;			/* The number of buffer headers */
diff --git a/sys/ufs/ffs/ffs_alloc.c b/sys/ufs/ffs/ffs_alloc.c
--- a/sys/ufs/ffs/ffs_alloc.c
+++ b/sys/ufs/ffs/ffs_alloc.c
@@ -67,24 +67,25 @@
 #include "opt_quota.h"
 
 #include <sys/param.h>
-#include <sys/capsicum.h>
-#include <sys/gsb_crc32.h>
 #include <sys/systm.h>
 #include <sys/bio.h>
 #include <sys/buf.h>
+#include <sys/capsicum.h>
 #include <sys/conf.h>
 #include <sys/fcntl.h>
 #include <sys/file.h>
 #include <sys/filedesc.h>
+#include <sys/gsb_crc32.h>
+#include <sys/kernel.h>
+#include <sys/mount.h>
 #include <sys/priv.h>
 #include <sys/proc.h>
-#include <sys/vnode.h>
-#include <sys/mount.h>
-#include <sys/kernel.h>
+#include <sys/stat.h>
 #include <sys/syscallsubr.h>
 #include <sys/sysctl.h>
 #include <sys/syslog.h>
 #include <sys/taskqueue.h>
+#include <sys/vnode.h>
 
 #include <security/audit/audit.h>
 
@@ -270,6 +271,9 @@
 	fs = ump->um_fs;
 	bp = NULL;
 	gbflags = (flags & BA_UNMAPPED) != 0 ? GB_UNMAPPED : 0;
+#ifdef WITNESS
+	gbflags |= IS_SNAPSHOT(ip) ? GB_NOWITNESS : 0;
+#endif
 
 	mtx_assert(UFS_MTX(ump), MA_OWNED);
 #ifdef INVARIANTS
diff --git a/sys/ufs/ffs/ffs_balloc.c b/sys/ufs/ffs/ffs_balloc.c
--- a/sys/ufs/ffs/ffs_balloc.c
+++ b/sys/ufs/ffs/ffs_balloc.c
@@ -70,6 +70,7 @@
 #include <sys/buf.h>
 #include <sys/lock.h>
 #include <sys/mount.h>
+#include <sys/stat.h>
 #include <sys/vnode.h>
 #include <sys/vmmeter.h>
 
@@ -612,7 +613,7 @@
 	int deallocated, osize, nsize, num, i, error;
 	int unwindidx = -1;
 	int saved_inbdflush;
-	int gbflags, reclaimed;
+	int gbflags, gbwflag, reclaimed;
 
 	ip = VTOI(vp);
 	dp = ip->i_din2;
@@ -628,6 +629,12 @@
 	if (lbn < 0)
 		return (EFBIG);
 	gbflags = (flags & BA_UNMAPPED) != 0 ? GB_UNMAPPED : 0;
+#ifdef WITNESS
+	gbwflag = IS_SNAPSHOT(ip) ? GB_NOWITNESS : 0;
+	gbflags |= gbwflag;
+#else
+	gbwflag = 0;
+#endif
 
 	vn_seqc_write_begin(vp);
 
@@ -889,7 +896,7 @@
 		*allocblk++ = nb;
 		*lbns_remfree++ = indirs[1].in_lbn;
 		bp = getblk(vp, indirs[1].in_lbn, fs->fs_bsize, 0, 0,
-		    GB_UNMAPPED);
+		    GB_UNMAPPED | gbwflag);
 		bp->b_blkno = fsbtodb(fs, nb);
 		vfs_bio_clrbuf(bp);
 		if (DOINGSOFTDEP(vp)) {
@@ -914,8 +921,8 @@
 	 */
 retry:
 	for (i = 1;;) {
-		error = bread(vp,
-		    indirs[i].in_lbn, (int)fs->fs_bsize, NOCRED, &bp);
+		error = bread_gb(vp, indirs[i].in_lbn, (int)fs->fs_bsize,
+		    NOCRED, gbwflag, &bp);
 		if (error) {
 			goto fail;
 		}
@@ -1138,7 +1145,7 @@
 		 * buffer object lists.
 		 */
 		bp = getblk(vp, *lbns_remfree, fs->fs_bsize, 0, 0,
-		    GB_NOCREAT | GB_UNMAPPED);
+		    GB_NOCREAT | GB_UNMAPPED | gbwflag);
 		if (bp != NULL) {
 			KASSERT(bp->b_blkno == fsbtodb(fs, *blkp),
 			    ("mismatch2 l %jd %jd b %ju %ju",
@@ -1156,8 +1163,8 @@
 	} else if (unwindidx >= 0) {
 		int r;
 
-		r = bread(vp, indirs[unwindidx].in_lbn, 
-		    (int)fs->fs_bsize, NOCRED, &bp);
+		r = bread_gb(vp, indirs[unwindidx].in_lbn,
+		    (int)fs->fs_bsize, NOCRED, gbwflag, &bp);
 		if (r) {
 			panic("Could not unwind indirect block, error %d", r);
 			brelse(bp);
@@ -1193,7 +1200,7 @@
 		if (blkp == allociblk)
 			lbns_remfree = lbns;
 		bp = getblk(vp, *lbns_remfree, fs->fs_bsize, 0, 0,
-		    GB_NOCREAT | GB_UNMAPPED);
+		    GB_NOCREAT | GB_UNMAPPED | gbwflag);
 		if (bp != NULL) {
 			panic("zombie2 %jd %ju %ju",
 			    (intmax_t)bp->b_lblkno, (uintmax_t)bp->b_blkno,
diff --git a/sys/ufs/ffs/ffs_vnops.c b/sys/ufs/ffs/ffs_vnops.c
--- a/sys/ufs/ffs/ffs_vnops.c
+++ b/sys/ufs/ffs/ffs_vnops.c
@@ -261,12 +261,17 @@
 	struct ufsmount *ump;
 	struct buf *bp, *nbp;
 	ufs_lbn_t lbn;
-	int error, passes;
+	int error, passes, wflag;
 	bool still_dirty, unlocked, wait;
 
 	ip = VTOI(vp);
 	bo = &vp->v_bufobj;
 	ump = VFSTOUFS(vp->v_mount);
+#ifdef WITNESS
+	wflag = IS_SNAPSHOT(ip) ? LK_NOWITNESS : 0;
+#else
+	wflag = 0;
+#endif
 
 	/*
 	 * When doing MNT_WAIT we must first flush all dependencies
@@ -318,9 +323,8 @@
 		if (BUF_LOCK(bp, LK_EXCLUSIVE | LK_NOWAIT, NULL) == 0) {
 			BO_UNLOCK(bo);
 		} else if (wait) {
-			if (BUF_LOCK(bp,
-			    LK_EXCLUSIVE | LK_SLEEPFAIL | LK_INTERLOCK,
-			    BO_LOCKPTR(bo)) != 0) {
+			if (BUF_LOCK(bp, LK_EXCLUSIVE | LK_SLEEPFAIL |
+			    LK_INTERLOCK | wflag, BO_LOCKPTR(bo)) != 0) {
 				BO_LOCK(bo);
 				bp->b_vflags &= ~BV_SCANNED;
 				goto next_locked;