[PATCH v3] generic: test truncating mixed written/unwritten XFS realtime extent

Omar Sandoval
2019-12-03T23:52:01Z

From: Omar Sandoval <osandov@fb.com>

The only XFS-specific part of this test is the setup, so we can make the
rest a generic test. It's slow, though, as it needs to write 8GB to
convert a big unwritten extent to written.

Signed-off-by: Omar Sandoval <osandov@fb.com>
---
Changes from v2 -> v3:

- Use _create_loop_device and _destroy_loop_device instead of losetup

Changes from v1 -> v2:

- If rtdev is not configured, fall back to loop device on test
filesystem
- Use XFS_IO_PROG instead of fallocate/sync/dd
- Use truncate instead of rm
- Add comments explaining the steps

tests/generic/589 | 100 ++++++++++++++++++++++++++++++++++++++++++
tests/generic/589.out | 2 +
tests/generic/group | 1 +
3 files changed, 103 insertions(+)
create mode 100755 tests/generic/589
create mode 100644 tests/generic/589.out

diff --git a/tests/generic/589 b/tests/generic/589
new file mode 100755
index 00000000..aab37bb4
--- /dev/null
+++ b/tests/generic/589
@@ -0,0 +1,100 @@
+#! /bin/bash
+# SPDX-License-Identifier: GPL-2.0
+# Copyright (c) 2019 Facebook. All Rights Reserved.
+#
+# FS QA Test 589
+#
+# Test "xfs: fix realtime file data space leak" and "xfs: don't check for AG
+# deadlock for realtime files in bunmapi". On XFS without the fix, truncate
+# will hang forever. On other filesystems, this just tests writing into big
+# fallocates.
+#
+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 $tmp.*
+ test -n "$loop" && _destroy_loop_device "$loop"
+ rm -f "$TEST_DIR/$seq"
+}
+
+. ./common/rc
+. ./common/filter
+
+rm -f $seqres.full
+
+_supported_fs generic
+_supported_os Linux
+_require_scratch_nocheck
+
+maxextlen=$((0x1fffff))
+bs=4096
+rextsize=4
+filesz=$(((maxextlen + 1) * bs))
+
+extra_options=""
+# If we're testing XFS, set up the realtime device to reproduce the bug.
+if [[ $FSTYP = xfs ]]; then
+ # If we don't have a realtime device, set up a loop device on the test
+ # filesystem.
+ if [[ $USE_EXTERNAL != yes || -z $SCRATCH_RTDEV ]]; then
+ _require_test
+ loopsz="$((filesz + (1 << 26)))"
+ _require_fs_space "$TEST_DIR" $((loopsz / 1024))
+ $XFS_IO_PROG -c "truncate $loopsz" -f "$TEST_DIR/$seq"
+ loop="$(_create_loop_device "$TEST_DIR/$seq")"
+ USE_EXTERNAL=yes
+ SCRATCH_RTDEV="$loop"
+ fi
+ extra_options="$extra_options -bsize=$bs"
+ extra_options="$extra_options -r extsize=$((bs * rextsize))"
+ extra_options="$extra_options -d agsize=$(((maxextlen + 1) * bs / 2)),rtinherit=1"
+fi
+_scratch_mkfs $extra_options >>$seqres.full 2>&1
+_scratch_mount
+_require_fs_space "$SCRATCH_MNT" $((filesz / 1024))
+
+# Allocate maxextlen + 1 blocks. As long as the allocator does something sane,
+# we should end up with two extents that look something like:
+#
+# u3.bmx[0-1] = [startoff,startblock,blockcount,extentflag]
+# 0:[0,0,2097148,1]
+# 1:[2097148,2097148,4,1]
+#
+# Extent 0 has blockcount = ALIGN_DOWN(maxextlen, rextsize). Extent 1 is
+# adjacent and has blockcount = rextsize. Both are unwritten.
+$XFS_IO_PROG -c "falloc 0 $filesz" -c fsync -f "$SCRATCH_MNT/file"
+
+# Write extent 0 + one block of extent 1. Our extents should end up like so:
+#
+# u3.bmx[0-1] = [startoff,startblock,blockcount,extentflag]
+# 0:[0,0,2097149,0]
+# 1:[2097149,2097149,3,1]
+#
+# Extent 0 is written and has blockcount = ALIGN_DOWN(maxextlen, rextsize) + 1,
+# Extent 1 is adjacent, unwritten, and has blockcount = rextsize - 1 and
+# startblock % rextsize = 1.
+#
+# The -b is just to speed things up (doing GBs of I/O in 4k chunks kind of
+# sucks).
+$XFS_IO_PROG -c "pwrite -b 1M -W 0 $(((maxextlen + 2 - rextsize) * bs))" \
+ "$SCRATCH_MNT/file" >> "$seqres.full"
+
+# Truncate the extents.
+$XFS_IO_PROG -c "truncate 0" -c fsync "$SCRATCH_MNT/file"
+
+# We need to do this before the loop device gets torn down.
+_scratch_unmount
+_check_scratch_fs
+
+echo "Silence is golden"
+status=0
+exit
diff --git a/tests/generic/589.out b/tests/generic/589.out
new file mode 100644
index 00000000..5ab6ab10
--- /dev/null
+++ b/tests/generic/589.out
@@ -0,0 +1,2 @@
+QA output created by 589
+Silence is golden
diff --git a/tests/generic/group b/tests/generic/group
index 87d7441c..be6f4a43 100644
--- a/tests/generic/group
+++ b/tests/generic/group
@@ -591,3 +591,4 @@
586 auto quick rw prealloc
587 auto quick rw prealloc
588 auto quick log clone
+589 auto prealloc preallocrw dangerous
--
2.24.0