diff --git a/ltp/fsx.c b/ltp/fsx.c
index f51d38cf..577c7309 100644
--- a/ltp/fsx.c
+++ b/ltp/fsx.c
@@ -105,6 +105,7 @@ enum {
 	OP_COLLAPSE_RANGE,
 	OP_INSERT_RANGE,
 	OP_CLONE_RANGE,
+	OP_DEDUPE_RANGE,
 	OP_MAX_FULL,
 
 	/* integrity operations */
@@ -167,6 +168,7 @@ int	insert_range_calls = 1;		/* -I flag disables */
 int	mapped_reads = 1;		/* -R flag disables it */
 int	check_file = 0;			/* -X flag enables */
 int	clone_range_calls = 1;		/* -J flag disables */
+int	dedupe_range_calls = 1;		/* -B flag disables */
 int	integrity = 0;			/* -i flag */
 int	fsxgoodfd = 0;
 int	o_direct;			/* -Z */
@@ -261,6 +263,7 @@ static const char *op_names[] = {
 	[OP_COLLAPSE_RANGE] = "collapse_range",
 	[OP_INSERT_RANGE] = "insert_range",
 	[OP_CLONE_RANGE] = "clone_range",
+	[OP_DEDUPE_RANGE] = "dedupe_range",
 	[OP_FSYNC] = "fsync",
 };
 
@@ -460,6 +463,20 @@ logdump(void)
 			else if (overlap2)
 				prt("\t******JJJJ");
 			break;
+		case OP_DEDUPE_RANGE:
+			prt("DEDUPE 0x%x thru 0x%x\t(0x%x bytes) to 0x%x thru 0x%x",
+			    lp->args[0], lp->args[0] + lp->args[1] - 1,
+			    lp->args[1],
+			    lp->args[2], lp->args[2] + lp->args[1] - 1);
+			overlap2 = badoff >= lp->args[2] &&
+				  badoff < lp->args[2] + lp->args[1];
+			if (overlap && overlap2)
+				prt("\tBBBB**BBBB");
+			else if (overlap)
+				prt("\tBBBB******");
+			else if (overlap2)
+				prt("\t******BBBB");
+			break;
 		case OP_FSYNC:
 			prt("FSYNC");
 			break;
@@ -1391,6 +1408,137 @@ do_clone_range(unsigned offset, unsigned length, unsigned dest)
 }
 #endif
 
+#ifdef FIDEDUPERANGE
+int
+test_dedupe_range(void)
+{
+	struct file_dedupe_range *fdr;
+	off_t new_len;
+	int error;
+	int ret = 1;
+
+	/* Alloc memory */
+	fdr = calloc(sizeof(struct file_dedupe_range_info) +
+		     sizeof(struct file_dedupe_range), 1);
+	if (!fdr) {
+		prterr("do_dedupe_range: malloc");
+		report_failure(161);
+	}
+
+	/* Make sure we have at least two blocks */
+	new_len = block_size * 2;
+	if (file_size < new_len && ftruncate(fd, new_len)) {
+		warn("main: ftruncate");
+		exit(132);
+	}
+
+	/* Try to dedupe them */
+	fdr->src_length = block_size;
+	fdr->dest_count = 1;
+	fdr->info[0].dest_fd = fd;
+	fdr->info[0].dest_offset = block_size;
+
+	if (ioctl(fd, FIDEDUPERANGE, fdr))
+		error = errno;
+	else if (fdr->info[0].status < 0)
+		error = -fdr->info[0].status;
+	else
+		error = 0;
+
+	if (error == EOPNOTSUPP || error == ENOTTY) {
+		if (!quiet)
+			fprintf(stderr,
+				"main: filesystem does not support "
+				"dedupe range, disabling!\n");
+		ret = 0;
+	}
+
+	/* Put the file back the way it was. */
+	if (file_size < new_len && ftruncate(fd, file_size)) {
+		warn("main: ftruncate");
+		exit(132);
+	}
+
+	free(fdr);
+	return ret;
+}
+
+void
+do_dedupe_range(unsigned offset, unsigned length, unsigned dest)
+{
+	struct file_dedupe_range *fdr;
+
+	if (length == 0) {
+		if (!quiet && testcalls > simulatedopcount)
+			prt("skipping zero length dedupe range\n");
+		log5(OP_DEDUPE_RANGE, offset, length, dest, FL_SKIPPED);
+		return;
+	}
+
+	if ((loff_t)offset >= file_size) {
+		if (!quiet && testcalls > simulatedopcount)
+			prt("skipping dedupe range behind EOF\n");
+		log5(OP_DEDUPE_RANGE, offset, length, dest, FL_SKIPPED);
+		return;
+	}
+
+	log5(OP_DEDUPE_RANGE, offset, length, dest, FL_NONE);
+
+	if (testcalls <= simulatedopcount)
+		return;
+
+	if ((progressinterval && testcalls % progressinterval == 0) ||
+	    (debug && (monitorstart == -1 || monitorend == -1 ||
+		       dest <= monitorstart || dest + length <= monitorend))) {
+		prt("%lu dedupe\tfrom 0x%x to 0x%x, (0x%x bytes) at 0x%x\n",
+			testcalls, offset, offset+length, length, dest);
+	}
+
+	/* Alloc memory */
+	fdr = calloc(sizeof(struct file_dedupe_range_info) +
+		     sizeof(struct file_dedupe_range), 1);
+	if (!fdr) {
+		prterr("do_dedupe_range: malloc");
+		report_failure(161);
+	}
+
+	/* Dedupe data blocks */
+	fdr->src_offset = offset;
+	fdr->src_length = length;
+	fdr->dest_count = 1;
+	fdr->info[0].dest_fd = fd;
+	fdr->info[0].dest_offset = dest;
+
+	if (ioctl(fd, FIDEDUPERANGE, fdr) == -1) {
+		prt("dedupe range: 0x%x to 0x%x at 0x%x\n", offset,
+				offset + length, dest);
+		prterr("do_dedupe_range(0): FIDEDUPERANGE");
+		report_failure(161);
+	} else if (fdr->info[0].status < 0) {
+		errno = -fdr->info[0].status;
+		prt("dedupe range: 0x%x to 0x%x at 0x%x\n", offset,
+				offset + length, dest);
+		prterr("do_dedupe_range(1): FIDEDUPERANGE");
+		report_failure(161);
+	}
+
+	free(fdr);
+}
+
+#else
+int
+test_dedupe_range(void)
+{
+	return 0;
+}
+
+void
+do_dedupe_range(unsigned offset, unsigned length, unsigned dest)
+{
+	return;
+}
+#endif
+
 #ifdef HAVE_LINUX_FALLOC_H
 /* fallocate is basically a no-op unless extending, then a lot like a truncate */
 void
@@ -1549,6 +1697,7 @@ op_args_count(int operation)
 {
 	switch (operation) {
 	case OP_CLONE_RANGE:
+	case OP_DEDUPE_RANGE:
 		return 4;
 	default:
 		return 3;
@@ -1704,6 +1853,25 @@ test(void)
 		} while (llabs(offset2 - offset) < size ||
 			 offset2 + size > maxfilelen);
 		break;
+	case OP_DEDUPE_RANGE:
+		{
+			int tries = 0;
+
+			TRIM_OFF_LEN(offset, size, file_size);
+			offset = offset & ~(block_size - 1);
+			size = size & ~(block_size - 1);
+			do {
+				if (tries++ >= 30) {
+					size = 0;
+					break;
+				}
+				offset2 = random();
+				TRIM_OFF(offset2, file_size);
+				offset2 = offset2 & ~(block_size - 1);
+			} while (llabs(offset2 - offset) < size ||
+				 offset2 + size > file_size);
+			break;
+		}
 	}
 
 have_op:
@@ -1753,6 +1921,12 @@ test(void)
 			goto out;
 		}
 		break;
+	case OP_DEDUPE_RANGE:
+		if (!dedupe_range_calls) {
+			log5(op, offset, size, offset2, FL_SKIPPED);
+			goto out;
+		}
+		break;
 	}
 
 	switch (op) {
@@ -1831,6 +2005,18 @@ test(void)
 
 		do_clone_range(offset, size, offset2);
 		break;
+	case OP_DEDUPE_RANGE:
+		if (size == 0) {
+			log5(OP_DEDUPE_RANGE, offset, size, offset2, FL_SKIPPED);
+			goto out;
+		}
+		if (offset2 + size > maxfilelen) {
+			log5(OP_DEDUPE_RANGE, offset, size, offset2, FL_SKIPPED);
+			goto out;
+		}
+
+		do_dedupe_range(offset, size, offset2);
+		break;
 	case OP_FSYNC:
 		dofsync();
 		break;
@@ -1856,7 +2042,7 @@ void
 usage(void)
 {
 	fprintf(stdout, "usage: %s",
-		"fsx [-dknqxAFJLOWZ] [-b opnum] [-c Prob] [-g filldata] [-i logdev] [-j logid] [-l flen] [-m start:end] [-o oplen] [-p progressinterval] [-r readbdy] [-s style] [-t truncbdy] [-w writebdy] [-D startingop] [-N numops] [-P dirpath] [-S seed] fname\n\
+		"fsx [-dknqxABFJLOWZ] [-b opnum] [-c Prob] [-g filldata] [-i logdev] [-j logid] [-l flen] [-m start:end] [-o oplen] [-p progressinterval] [-r readbdy] [-s style] [-t truncbdy] [-w writebdy] [-D startingop] [-N numops] [-P dirpath] [-S seed] fname\n\
 	-b opnum: beginning operation number (default 1)\n\
 	-c P: 1 in P chance of file close+open at each op (default infinity)\n\
 	-d: debug output for all operations\n\
@@ -1900,6 +2086,9 @@ usage(void)
 #ifdef FICLONERANGE
 "	-J: Do not use clone range calls\n"
 #endif
+#ifdef FIDEDUPERANGE
+"	-B: Do not use dedupe range calls\n"
+#endif
 "	-L: fsxLite - no file creations & no file size changes\n\
 	-N numops: total # operations to do (default infinity)\n\
 	-O: use oplen (see -o flag) for every op (default random)\n\
@@ -2103,7 +2292,7 @@ main(int argc, char **argv)
 	setvbuf(stdout, (char *)0, _IOLBF, 0); /* line buffered stdout */
 
 	while ((ch = getopt_long(argc, argv,
-				 "b:c:dfg:i:j:kl:m:no:p:qr:s:t:w:xyAD:FJKHzCILN:OP:RS:WXZ",
+				 "b:c:dfg:i:j:kl:m:no:p:qr:s:t:w:xyABD:FJKHzCILN:OP:RS:WXZ",
 				 longopts, NULL)) != EOF)
 		switch (ch) {
 		case 'b':
@@ -2236,6 +2425,9 @@ main(int argc, char **argv)
 		case 'J':
 			clone_range_calls = 0;
 			break;
+		case 'B':
+			dedupe_range_calls = 0;
+			break;
 		case 'L':
 		        lite = 1;
 			o_flags &= ~(O_CREAT|O_TRUNC);
@@ -2456,6 +2648,8 @@ main(int argc, char **argv)
 		insert_range_calls = test_fallocate(FALLOC_FL_INSERT_RANGE);
 	if (clone_range_calls)
 		clone_range_calls = test_clone_range();
+	if (dedupe_range_calls)
+		dedupe_range_calls = test_dedupe_range();
 
 	while (numops == -1 || numops--)
 		if (!test())
