btrfs: add a test case for btrfs seed device delete

This is a regression test for the issue fixed by the kernel commit
b5ddcffa3777 (btrfs: fix put of uninitialized kobject after seed device
delete).

In this test case, we verify the seed device delete on a sprouted
filesystem.

Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Eryu Guan <guaneryu@gmail.com>

tests/btrfs/225

@@ -0,0 +1,82 @@
+#! /bin/bash
+# SPDX-License-Identifier: GPL-2.0
+# Copyright (c) 2020 Oracle. All Rights Reserved.
+#
+# FS QA Test 225
+#
+# Test for seed device-delete on a sprouted FS.
+# Requires kernel patch
+#    b5ddcffa3777  btrfs: fix put of uninitialized kobject after seed device delete
+#
+# Steps:
+#  Create a seed FS. Add a RW device to make it sprout FS and then delete
+#  the seed device.
+
+seq=`basename $0`
+seqres=$RESULT_DIR/$seq
+echo "QA output created by $seq"
+
+here=`pwd`
+tmp=/tmp/$$
+status=1	# failure is the default!
+trap "_cleanup; exit \$status" 0 1 2 3 15
+
+_cleanup()
+{
+	cd /
+	rm -f $tmp.*
+}
+
+# get standard environment, filters and checks
+. ./common/rc
+. ./common/filter
+
+# remove previous $seqres.full before test
+rm -f $seqres.full
+
+# real QA test starts here
+
+# Modify as appropriate.
+_supported_fs btrfs
+_require_test
+_require_scratch_dev_pool 2
+
+_scratch_dev_pool_get 2
+
+seed=$(echo $SCRATCH_DEV_POOL | $AWK_PROG '{print $1}')
+sprout=$(echo $SCRATCH_DEV_POOL | $AWK_PROG '{print $2}')
+
+_mkfs_dev $seed
+_mount $seed $SCRATCH_MNT
+
+$XFS_IO_PROG -f -c "pwrite -S 0xab 0 1M" $SCRATCH_MNT/foo > /dev/null
+_scratch_unmount
+$BTRFS_TUNE_PROG -S 1 $seed
+
+# Mount the seed device and add the rw device
+_mount -o ro $seed $SCRATCH_MNT
+$BTRFS_UTIL_PROG device add -f $sprout $SCRATCH_MNT
+_scratch_unmount
+
+# Now remount
+_mount $sprout $SCRATCH_MNT
+$XFS_IO_PROG -f -c "pwrite -S 0xcd 0 1M" $SCRATCH_MNT/bar > /dev/null
+
+echo --- before delete ----
+od -x $SCRATCH_MNT/foo
+od -x $SCRATCH_MNT/bar
+
+$BTRFS_UTIL_PROG device delete $seed $SCRATCH_MNT
+_scratch_unmount
+_btrfs_forget_or_module_reload
+_mount $sprout $SCRATCH_MNT
+
+echo --- after delete ----
+od -x $SCRATCH_MNT/foo
+od -x $SCRATCH_MNT/bar
+
+_scratch_dev_pool_put
+
+# success, all done
+status=0
+exit

tests/btrfs/225.out

@@ -0,0 +1,15 @@
+QA output created by 225
+--- before delete ----
+0000000 abab abab abab abab abab abab abab abab
+*
+4000000
+0000000 cdcd cdcd cdcd cdcd cdcd cdcd cdcd cdcd
+*
+4000000
+--- after delete ----
+0000000 abab abab abab abab abab abab abab abab
+*
+4000000
+0000000 cdcd cdcd cdcd cdcd cdcd cdcd cdcd cdcd
+*
+4000000

tests/btrfs/group

@@ -226,3 +226,4 @@
 222 auto quick send
 223 auto quick replace trim
 224 auto quick qgroup
+225 auto quick volume seed