--- /dev/null
+#!/bin/bash
+# Test if "-m single" or "--mixed" can cause dev extent to use the reserved 1M
+# range
+#
+# Other profiles will cause mkfs.btrfs to allocate new meta/sys chunks
+# using btrfs_alloc_chunk() which won't use the 0~1M range, so other profiles
+# are safe.
+
+source "$TOP/tests/common"
+
+check_prereq mkfs.btrfs
+check_prereq btrfs
+
+prepare_test_dev
+
+do_one_test ()
+{
+ run_check "$TOP/mkfs.btrfs" -f "$@" "$TEST_DEV"
+
+ # Use dev-extent tree to find first device extent
+ first_dev_extent=$(run_check_stdout "$TOP/btrfs" inspect-internal \
+ dump-tree -t device "$TEST_DEV" | \
+ grep -oP '(?<=DEV_EXTENT )[[:digit:]]*' | head -n1)
+
+ if [ -z $first_dev_extent ]; then
+ _fail "failed to get first device extent"
+ fi
+
+ echo "first dev extent starts at $first_dev_extent" >> "$RESULTS"
+ echo "reserved range is [0, $(( 1024 * 1024)))" >> "$RESULTS"
+ # First device extent should not start below 1M
+ if [ $first_dev_extent -lt $(( 1024 * 1024 )) ]; then
+ _fail "first device extent occupies reserved 0~1M range"
+ fi
+}
+
+do_one_test --mixed
+do_one_test -m single