[PATCH V3 2/2] xfs: Check if rt summary/bitmap buffers are logged with correct xfs_buf type

[Chandan Babu R <chandanrlinux@gmail.com>]

This commit adds a test to check if growing a real-time device can end
up logging an xfs_buf with the "type" subfield of
bip->bli_formats->blf_flags set to XFS_BLFT_UNKNOWN_BUF. When this
occurs the following call trace is printed on the console,

XFS: Assertion failed: (bip->bli_flags & XFS_BLI_STALE) || (xfs_blft_from_flags(&bip->__bli_format) > XFS_BLFT_UNKNOWN_BUF && xfs_blft_from_flags(&bip->__bli_format) < XFS_BLFT_MAX_BUF), file: fs/xfs/xfs_buf_item.c, line: 331
Call Trace:
 xfs_buf_item_format+0x632/0x680
 ? kmem_alloc_large+0x29/0x90
 ? kmem_alloc+0x70/0x120
 ? xfs_log_commit_cil+0x132/0x940
 xfs_log_commit_cil+0x26f/0x940
 ? xfs_buf_item_init+0x1ad/0x240
 ? xfs_growfs_rt_alloc+0x1fc/0x280
 __xfs_trans_commit+0xac/0x370
 xfs_growfs_rt_alloc+0x1fc/0x280
 xfs_growfs_rt+0x1a0/0x5e0
 xfs_file_ioctl+0x3fd/0xc70
 ? selinux_file_ioctl+0x174/0x220
 ksys_ioctl+0x87/0xc0
 __x64_sys_ioctl+0x16/0x20
 do_syscall_64+0x3e/0x70
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

The kernel patch "xfs: Set xfs_buf type flag when growing summary/bitmap
files" is required to fix this issue.

Reviewed-by: Zorro Lang <zlang@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Chandan Babu R <chandanrlinux@gmail.com>
---
Changelog:
V2 -> V3:
  1. Remove unnecessary invocation of _scratch_unmount at the end of the test.

V1 -> V2:
  1. Use _scratch_mkfs instead of invoking _mkfs_dev directly.
  2. Remove unnecessary comments introduced by "new" script.
  3. Add the new test under quick, growfs and realtime groups.
  
 tests/xfs/260     | 51 +++++++++++++++++++++++++++++++++++++++++++++++
 tests/xfs/260.out |  2 ++
 tests/xfs/group   |  1 +
 3 files changed, 54 insertions(+)
 create mode 100755 tests/xfs/260
 create mode 100644 tests/xfs/260.out

diff --git a/tests/xfs/260 b/tests/xfs/260
new file mode 100755
index 00000000..1cafa368
--- /dev/null
+++ b/tests/xfs/260
@@ -0,0 +1,51 @@
+#! /bin/bash
+# SPDX-License-Identifier: GPL-2.0
+# Copyright (c) 2020 Chandan Babu R.  All Rights Reserved.
+#
+# FS QA Test 260
+#
+# Test to check if growing a real-time device can end up logging an xfs_buf with
+# the "type" subfield of bip->bli_formats->blf_flags set to
+# XFS_BLFT_UNKNOWN_BUF.
+#
+# This is a regression test for the kernel patch "xfs: Set xfs_buf type flag
+# when growing summary/bitmap files".
+
+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
+_supported_fs xfs
+_supported_os Linux
+_require_realtime
+
+_scratch_mkfs -r size=10M  >> $seqres.full
+
+_scratch_mount >> $seqres.full
+
+$XFS_GROWFS_PROG $SCRATCH_MNT >> $seqres.full
+
+echo "Silence is golden"
+
+# success, all done
+status=0
+exit
diff --git a/tests/xfs/260.out b/tests/xfs/260.out
new file mode 100644
index 00000000..18ca517c
--- /dev/null
+++ b/tests/xfs/260.out
@@ -0,0 +1,2 @@
+QA output created by 260
+Silence is golden
diff --git a/tests/xfs/group b/tests/xfs/group
index b8374359..3b38a604 100644
--- a/tests/xfs/group
+++ b/tests/xfs/group
@@ -257,6 +257,7 @@
 257 auto quick clone
 258 auto quick clone
 259 auto quick
+260 auto quick growfs realtime
 261 auto quick quota
 262 dangerous_fuzzers dangerous_scrub dangerous_online_repair
 263 auto quick quota
-- 
2.28.0