From c2a8e177817e15d3b1a7ddc1a61a11e91a41e985 Mon Sep 17 00:00:00 2001 From: "Darrick J. Wong" Date: Tue, 11 Jan 2022 13:50:35 -0800 Subject: [PATCH] xfs: regression test for allocsp handing out stale disk contents Add a regression test to check that XFS_IOC_ALLOCSP isn't handing out stale disk blocks for preallocation. Signed-off-by: Darrick J. Wong Reviewed-by: Eryu Guan Signed-off-by: Eryu Guan --- .gitignore | 1 + src/Makefile | 2 +- src/allocstale.c | 117 ++++++++++++++++++++++++++++++++++++++++++++++ tests/xfs/107 | 57 ++++++++++++++++++++++ tests/xfs/107.out | 2 + 5 files changed, 178 insertions(+), 1 deletion(-) create mode 100644 src/allocstale.c create mode 100755 tests/xfs/107 create mode 100644 tests/xfs/107.out diff --git a/.gitignore b/.gitignore index 65b93307..ba0c572b 100644 --- a/.gitignore +++ b/.gitignore @@ -56,6 +56,7 @@ tags # src/ binaries /src/af_unix /src/alloc +/src/allocstale /src/append_reader /src/append_writer /src/attr_replace_test diff --git a/src/Makefile b/src/Makefile index 1737ed0e..111ce1d9 100644 --- a/src/Makefile +++ b/src/Makefile @@ -18,7 +18,7 @@ TARGETS = dirstress fill fill2 getpagesize holes lstat64 \ t_ext4_dax_journal_corruption t_ext4_dax_inline_corruption \ t_ofd_locks t_mmap_collision mmap-write-concurrent \ t_get_file_time t_create_short_dirs t_create_long_dirs t_enospc \ - t_mmap_writev_overlap checkpoint_journal mmap-rw-fault + t_mmap_writev_overlap checkpoint_journal mmap-rw-fault allocstale LINUX_TARGETS = xfsctl bstat t_mtab getdevicesize preallo_rw_pattern_reader \ preallo_rw_pattern_writer ftrunc trunc fs_perms testx looptest \ diff --git a/src/allocstale.c b/src/allocstale.c new file mode 100644 index 00000000..6253fe4c --- /dev/null +++ b/src/allocstale.c @@ -0,0 +1,117 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2022 Oracle. All Rights Reserved. + * Author: Darrick J. Wong + * + * Test program to try to trip over XFS_IOC_ALLOCSP mapping stale disk blocks + * into a file. + */ +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#ifndef XFS_IOC_ALLOCSP +# define XFS_IOC_ALLOCSP _IOW ('X', 10, struct xfs_flock64) +#endif + +int +main( + int argc, + char *argv[]) +{ + struct stat sb; + char *buf, *zeroes; + unsigned long i; + unsigned long iterations; + int fd, ret; + + if (argc != 3) { + fprintf(stderr, "Usage: %s filename iterations\n", argv[0]); + return 1; + } + + errno = 0; + iterations = strtoul(argv[2], NULL, 0); + if (errno) { + perror(argv[2]); + return 1; + } + + fd = open(argv[1], O_RDWR | O_CREAT | O_TRUNC, 0600); + if (fd < 0) { + perror(argv[1]); + return 1; + } + + ret = fstat(fd, &sb); + if (ret) { + perror(argv[1]); + return 1; + } + + buf = malloc(sb.st_blksize); + if (!buf) { + perror("pread buffer"); + return 1; + } + + zeroes = calloc(1, sb.st_blksize); + if (!zeroes) { + perror("zeroes buffer"); + return 1; + } + + for (i = 1; i <= iterations; i++) { + struct xfs_flock64 arg = { }; + ssize_t read_bytes; + off_t offset = sb.st_blksize * i; + + /* Ensure the last block of the file is a hole... */ + ret = ftruncate(fd, offset - 1); + if (ret) { + perror("truncate"); + return 1; + } + + /* + * ...then use ALLOCSP to allocate the last block in the file. + * An unpatched kernel neglects to mark the new mapping + * unwritten or to zero the ondisk block, so... + */ + arg.l_whence = SEEK_SET; + arg.l_start = offset; + ret = ioctl(fd, XFS_IOC_ALLOCSP, &arg); + if (ret < 0) { + perror("ioctl"); + return 1; + } + + /* ... we can read old disk contents here. */ + read_bytes = pread(fd, buf, sb.st_blksize, + offset - sb.st_blksize); + if (read_bytes < 0) { + perror(argv[1]); + return 1; + } + if (read_bytes != sb.st_blksize) { + fprintf(stderr, "%s: short read of %zd bytes\n", + argv[1], read_bytes); + return 1; + } + + if (memcmp(zeroes, buf, sb.st_blksize) != 0) { + fprintf(stderr, "%s: found junk near offset %zd!\n", + argv[1], offset - sb.st_blksize); + return 2; + } + } + + return 0; +} diff --git a/tests/xfs/107 b/tests/xfs/107 new file mode 100755 index 00000000..6034dbc2 --- /dev/null +++ b/tests/xfs/107 @@ -0,0 +1,57 @@ +#! /bin/bash +# SPDX-License-Identifier: GPL-2.0 +# Copyright (c) 2022 Oracle. All Rights Reserved. +# +# FS QA Test No. 107 +# +# Regression test for commit: +# +# 983d8e60f508 ("xfs: map unwritten blocks in XFS_IOC_{ALLOC,FREE}SP just like fallocate") +# +. ./common/preamble +_begin_fstest auto quick prealloc + +# Import common functions. +. ./common/filter + +# real QA test starts here + +# Modify as appropriate. +_supported_fs xfs +_require_test +_require_scratch +_require_test_program allocstale + +size_mb=32 +# Write a known pattern to the disk so that we can detect stale disk blocks +# being mapped into the file. In the test author's experience, the bug will +# reproduce within the first 500KB's worth of ALLOCSP calls, so running up +# to 16MB should suffice. +$XFS_IO_PROG -d -c "pwrite -S 0x58 -b 8m 0 ${size_mb}m" $SCRATCH_DEV > $seqres.full +MKFS_OPTIONS="-K $MKFS_OPTIONS" _scratch_mkfs_sized $((size_mb * 1048576)) >> $seqres.full + +_scratch_mount + +# Force the file to be created on the data device, which we pre-initialized +# with a known pattern. The bug exists in the generic bmap code, so the choice +# of backing device does not matter, and ignoring the rt device gets us out of +# needing to detect things like rt extent size. +_xfs_force_bdev data $SCRATCH_MNT +testfile=$SCRATCH_MNT/a + +# Allow the test program to expand the file to consume half the free space. +blksz=$(_get_file_block_size $SCRATCH_MNT) +iterations=$(( (size_mb / 2) * 1048576 / blksz)) +echo "Setting up $iterations runs for block size $blksz" >> $seqres.full + +# Run reproducer program and dump file contents if we see stale data. Full +# details are in the source for the C program, but in a nutshell we run ALLOCSP +# one block at a time to see if it'll give us blocks full of 'X'es. +$here/src/allocstale $testfile $iterations +res=$? +test $res -eq 2 && od -tx1 -Ad -c $testfile + +# success, all done +echo Silence is golden +status=0 +exit diff --git a/tests/xfs/107.out b/tests/xfs/107.out new file mode 100644 index 00000000..862bdfbd --- /dev/null +++ b/tests/xfs/107.out @@ -0,0 +1,2 @@ +QA output created by 107 +Silence is golden -- 2.30.2