diff --git a/.gitignore b/.gitignore
index 3b160209..f0fb72bd 100644
--- a/.gitignore
+++ b/.gitignore
@@ -205,6 +205,7 @@ tags
 /src/vfs/mount-idmapped
 /src/log-writes/replay-log
 /src/perf/*.pyc
+/src/filemap-fault
 
 # Symlinked files
 /tests/generic/035.out
diff --git a/src/Makefile b/src/Makefile
index e7442487..ab98a06f 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -34,7 +34,7 @@ LINUX_TARGETS = xfsctl bstat t_mtab getdevicesize preallo_rw_pattern_reader \
 	attr_replace_test swapon mkswap t_attr_corruption t_open_tmpfiles \
 	fscrypt-crypt-util bulkstat_null_ocount splice-test chprojid_fail \
 	detached_mounts_propagation ext4_resize t_readdir_3 splice2pipe \
-	uuid_ioctl t_snapshot_deleted_subvolume
+	uuid_ioctl t_snapshot_deleted_subvolume fiemap-fault
 
 EXTRA_EXECS = dmerror fill2attr fill2fs fill2fs_check scaleread.sh \
 	      btrfs_crc32c_forged_name.py popdir.pl popattr.py \
diff --git a/src/fiemap-fault.c b/src/fiemap-fault.c
new file mode 100644
index 00000000..73260068
--- /dev/null
+++ b/src/fiemap-fault.c
@@ -0,0 +1,74 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2024 Meta Platforms, Inc.  All Rights Reserved.
+ */
+
+#include <sys/ioctl.h>
+#include <sys/mman.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <linux/fs.h>
+#include <linux/types.h>
+#include <linux/fiemap.h>
+#include <err.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <string.h>
+#include <unistd.h>
+
+int prep_mmap_buffer(int fd, void **addr)
+{
+	struct stat st;
+	int ret;
+
+	ret = fstat(fd, &st);
+	if (ret)
+		err(1, "failed to stat %d", fd);
+
+	*addr = mmap(NULL, st.st_size, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0);
+	if (*addr == MAP_FAILED)
+		err(1, "failed to mmap %d", fd);
+
+	return st.st_size;
+}
+
+int main(int argc, char *argv[])
+{
+	struct fiemap *fiemap;
+	size_t sz, last = 0;
+	void *buf = NULL;
+	int ret, fd;
+
+	if (argc != 2)
+		errx(1, "no in and out file name arguments given");
+
+	fd = open(argv[1], O_RDWR, 0666);
+	if (fd == -1)
+		err(1, "failed to open %s", argv[1]);
+
+	sz = prep_mmap_buffer(fd, &buf);
+
+	fiemap = (struct fiemap *)buf;
+	fiemap->fm_flags = 0;
+	fiemap->fm_extent_count = (sz - sizeof(struct fiemap)) /
+				  sizeof(struct fiemap_extent);
+
+	while (last < sz) {
+		int i;
+
+		fiemap->fm_start = last;
+		fiemap->fm_length = sz - last;
+
+		ret = ioctl(fd, FS_IOC_FIEMAP, (unsigned long)fiemap);
+		if (ret < 0)
+			err(1, "fiemap failed %d", errno);
+		for (i = 0; i < fiemap->fm_mapped_extents; i++)
+		       last = fiemap->fm_extents[i].fe_logical +
+			       fiemap->fm_extents[i].fe_length;
+	}
+
+	munmap(buf, sz);
+	close(fd);
+	return 0;
+}
diff --git a/tests/generic/808 b/tests/generic/808
new file mode 100755
index 00000000..36015f35
--- /dev/null
+++ b/tests/generic/808
@@ -0,0 +1,48 @@
+#! /bin/bash
+# SPDX-License-Identifier: GPL-2.0
+# Copyright (c) 2024 Meta Platforms, Inc.  All Rights Reserved.
+#
+# FS QA Test 808
+#
+# Test fiemap into an mmaped buffer of the same file
+#
+# Create a reasonably large file, then run a program which mmaps it and uses
+# that as a buffer for an fiemap call.  This is a regression test for btrfs
+# where we used to hold a lock for the duration of the fiemap call which would
+# result in a deadlock if we page faulted.
+#
+. ./common/preamble
+_begin_fstest quick auto fiemap
+[ $FSTYP == "btrfs" ] && \
+	_fixed_by_kernel_commit b0ad381fa769 \
+		"btrfs: fix deadlock with fiemap and extent locking"
+
+_cleanup()
+{
+	rm -f $dst
+	cd /
+	rm -r -f $tmp.*
+}
+
+# real QA test starts here
+_supported_fs generic
+_require_test
+_require_odirect
+_require_test_program fiemap-fault
+dst=$TEST_DIR/$seq/fiemap-fault
+
+mkdir -p $TEST_DIR/$seq
+
+echo "Silence is golden"
+
+for i in $(seq 0 2 1000)
+do
+	$XFS_IO_PROG -d -f -c "pwrite -q $((i * 4096)) 4096" $dst
+done
+
+$here/src/fiemap-fault $dst
+
+# success, all done
+status=$?
+exit
+
diff --git a/tests/generic/808.out b/tests/generic/808.out
new file mode 100644
index 00000000..88253428
--- /dev/null
+++ b/tests/generic/808.out
@@ -0,0 +1,2 @@
+QA output created by 808
+Silence is golden
