From 83598d2f839d9c27d2fd4209124d7c288ea2861e Mon Sep 17 00:00:00 2001 From: Omar Sandoval Date: Tue, 28 May 2024 10:13:14 -0700 Subject: [PATCH] generic: test Btrfs fsync vs. size-extending prealloc write crash This is a regression test for a Btrfs bug, but there's nothing Btrfs-specific about it. Since it's a race, we just try to make the race happen in a loop and pass if it doesn't crash after all of our attempts. Signed-off-by: Omar Sandoval Reviewed-by: Filipe Manana Signed-off-by: Zorro Lang --- tests/generic/748 | 45 +++++++++++++++++++++++++++++++++++++++++++ tests/generic/748.out | 2 ++ 2 files changed, 47 insertions(+) create mode 100755 tests/generic/748 create mode 100644 tests/generic/748.out diff --git a/tests/generic/748 b/tests/generic/748 new file mode 100755 index 00000000..71b74166 --- /dev/null +++ b/tests/generic/748 @@ -0,0 +1,45 @@ +#! /bin/bash +# SPDX-License-Identifier: GPL-2.0 +# Copyright (c) Meta Platforms, Inc. and affiliates. +# +# FS QA Test 748 +# +# Repeatedly prealloc beyond i_size, set an xattr, direct write into the +# prealloc while extending i_size, then fdatasync. This is a regression test +# for a Btrfs crash. +# +. ./common/preamble +. ./common/attr +_begin_fstest auto quick log preallocrw dangerous + +_supported_fs generic +_require_scratch +_require_attrs +_require_odirect +_require_xfs_io_command falloc -k +[ "$FSTYP" = btrfs ] && _fixed_by_kernel_commit XXXXXXXXXXXX \ + "btrfs: fix crash on racing fsync and size-extending write into prealloc" + +# -i slows down xfs_io startup and makes the race much less reliable. +XFS_IO_PROG="$(echo "$XFS_IO_PROG" | sed 's/ -i\b//')" + +_scratch_mkfs >> $seqres.full 2>&1 || _fail "mkfs failed" +_scratch_mount + +blksz=$(_get_file_block_size "$SCRATCH_MNT") + +# On Btrfs, since this is the only file on the filesystem, its metadata is at +# the end of a B-tree leaf. We want an ordered extent completion to add an +# extent item at the end of the leaf while we're logging prealloc extents +# beyond i_size after an xattr was set. +for ((i = 0; i < 5000; i++)); do + $XFS_IO_PROG -ftd -c "falloc -k 0 $((blksz * 3))" -c "pwrite -q -w 0 $blksz" "$SCRATCH_MNT/file" + $SETFATTR_PROG -n user.a -v a "$SCRATCH_MNT/file" + $XFS_IO_PROG -d -c "pwrite -q -w $blksz $blksz" "$SCRATCH_MNT/file" +done + +# If it didn't crash, we're good. + +echo "Silence is golden" +status=0 +exit diff --git a/tests/generic/748.out b/tests/generic/748.out new file mode 100644 index 00000000..dc050a96 --- /dev/null +++ b/tests/generic/748.out @@ -0,0 +1,2 @@ +QA output created by 748 +Silence is golden -- 2.47.3