On 2023/11/21 17:28, Zorro Lang wrote:
On Mon, Nov 20, 2023 at 03:03:27PM +0800, Baokun Li wrote:
Append writes to a file approaching 16T and observe if a kernel crash is
caused by ext4_lblk_t overflow triggering BUG_ON at ext4_mb_new_inode_pa().
This is a regression test for commit bc056e7163ac ("ext4: fix BUG in
ext4_mb_new_inode_pa() due to overflow")
Signed-off-by: Baokun Li <libaokun1@xxxxxxxxxx>
---
V1->V2:
Changes to make the use case more generic, not just for testing
ext4.(ext4 and xfs have been tested)
Thanks for this change,
tests/generic/737 | 55 +++++++++++++++++++++++++++++++++++++++++++
tests/generic/737.out | 2 ++
2 files changed, 57 insertions(+)
create mode 100755 tests/generic/737
create mode 100644 tests/generic/737.out
diff --git a/tests/generic/737 b/tests/generic/737
new file mode 100755
index 00000000..a65c448b
--- /dev/null
+++ b/tests/generic/737
@@ -0,0 +1,55 @@
+#! /bin/bash
+# SPDX-License-Identifier: GPL-2.0
+# Copyright (c) 2023 HUAWEI. All Rights Reserved.
+#
+# FS QA Test No. 737
+#
+# Append writes to a file approaching 16T and observe if a kernel crash is
+# caused by ext4_lblk_t overflow triggering BUG_ON at ext4_mb_new_inode_pa().
+# This is a regression test for commit
+# bc056e7163ac ("ext4: fix BUG in ext4_mb_new_inode_pa() due to overflow")
+#
+#set -x
Useless comment "set -x"
Oh, I'm sorry, it was for debugging and I forgot to delete it.
+. ./common/preamble
+. ./common/populate
+_begin_fstest auto quick insert prealloc
+
+# real QA test starts here
+_fixed_by_kernel_commit bc056e7163ac \
+ "ext4: fix BUG in ext4_mb_new_inode_pa() due to overflow"
[[ "$FSTYP" =~ ext* ]] && ....
This looks good.
+
+_require_xfs_io_command "falloc"
+_require_xfs_io_command "finsert"
+
+# Initalize a 4k 100M fs
It might not be 4k block size, so this comment is useless. Or you can say
better to use "4k" block size to tigger the bug:)
OK!
+dev_size=$((100 * 1024 * 1024))
+_scratch_mkfs_sized $dev_size >>$seqres.full 2>&1 || _fail "mkfs failed"
+
+_scratch_mount
+blksz="$(_get_block_size ${SCRATCH_MNT})"
+_require_odirect $blksz
I think the _require_odirect can be move up, before the mkfs calling.
Totally agree!
+
+# Reserve 1M space
+$XFS_IO_PROG -f -c "falloc 0 1M" "${SCRATCH_MNT}/tmp" >> $seqres.full
+
+# Create a file (~16T) with logical block numbers close to overflow
+$XFS_IO_PROG -f -c "falloc 0 10M" "${SCRATCH_MNT}/file" >> $seqres.full
+insert_size=$((blksz * 4096 - 10 - 3))
+$XFS_IO_PROG -f -c "finsert 1M ${insert_size}M" "${SCRATCH_MNT}/file" >> $seqres.full
+
+# Filling up the free space ensures that the pre-allocated space is the reserved space.
+nr_free=$(stat -f -c '%f' ${SCRATCH_MNT})
+_fill_fs $((nr_free * blksz)) ${SCRATCH_MNT}/fill $blksz 0 >> $seqres.full 2>&1
+sync
+
+# Remove reserved space to gain free space for allocation
+rm -f ${SCRATCH_MNT}/tmp
+
+# Trying to allocate two blocks triggers BUG_ON.
+$XFS_IO_PROG -c "open -ad ${SCRATCH_MNT}/file" -c "pwrite -S 0xff 0 8192" >> $seqres.full
Shouldn't the 8192 be "$((2 * blksz))", if the comment says "two blocks" ?
Okay, I'll change it to "$((2 * blksz))".
I tried 1024 blocksize, really can't reproduce this bug, do you know why? Maybe
related with the falloc/finsert size?
I'm not sure why this isn't triggered at a block size of 1024, I haven't
looked into this in depth.
Anyway, it covers this bug on default block size of ext4, and can be a generic
test on other conditions.
Thanks,
Zorro
Yes! Thank you very much for your review!
+
+echo "Silence is golden"
+
+# success, all done
+status=0
+exit
diff --git a/tests/generic/737.out b/tests/generic/737.out
new file mode 100644
index 00000000..67b83d78
--- /dev/null
+++ b/tests/generic/737.out
@@ -0,0 +1,2 @@
+QA output created by 737
+Silence is golden
--
2.31.1
Thanks!
--
With Best Regards,
Baokun Li
.
