I'm working on a set of kernel patches to change how writeback errors are handled and reported in the kernel. Instead of reporting a writeback error to only the first fsync caller on the file, I aim to make the kernel report them once on every file description. This patch adds a test for the new behavior. Basically, open many fds to the same file, turn on dm_error, write to each of the fds, and then fsync them all to ensure that they all get an error back. To do that, I'm adding a new tools/dmerror script that the C program can use to load the error table. For now, that's all it can do, but we can fill it out with other commands as necessary. Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxx> --- common/dmerror | 13 ++-- doc/auxiliary-programs.txt | 8 +++ src/Makefile | 2 +- src/fsync-err.c | 161 +++++++++++++++++++++++++++++++++++++++++++++ tests/generic/999 | 76 +++++++++++++++++++++ tests/generic/999.out | 3 + tests/generic/group | 1 + tools/dmerror | 44 +++++++++++++ 8 files changed, 302 insertions(+), 6 deletions(-) create mode 100644 src/fsync-err.c create mode 100755 tests/generic/999 create mode 100644 tests/generic/999.out create mode 100755 tools/dmerror diff --git a/common/dmerror b/common/dmerror index d46c5d0b7266..238baa213b1f 100644 --- a/common/dmerror +++ b/common/dmerror @@ -23,22 +23,25 @@ if [ $? -eq 0 ]; then _notrun "Cannot run tests with DAX on dmerror devices" fi -_dmerror_init() +_dmerror_setup() { local dm_backing_dev=$SCRATCH_DEV - $DMSETUP_PROG remove error-test > /dev/null 2>&1 - local blk_dev_size=`blockdev --getsz $dm_backing_dev` DMERROR_DEV='/dev/mapper/error-test' DMLINEAR_TABLE="0 $blk_dev_size linear $dm_backing_dev 0" + DMERROR_TABLE="0 $blk_dev_size error $dm_backing_dev 0" +} + +_dmerror_init() +{ + _dmerror_setup + $DMSETUP_PROG remove error-test > /dev/null 2>&1 $DMSETUP_PROG create error-test --table "$DMLINEAR_TABLE" || \ _fatal "failed to create dm linear device" - - DMERROR_TABLE="0 $blk_dev_size error $dm_backing_dev 0" } _dmerror_mount() diff --git a/doc/auxiliary-programs.txt b/doc/auxiliary-programs.txt index 21ef118596b6..191ac0596511 100644 --- a/doc/auxiliary-programs.txt +++ b/doc/auxiliary-programs.txt @@ -16,6 +16,7 @@ note the dependency with: Contents: - af_unix -- Create an AF_UNIX socket + - fsync-err -- tests fsync error reporting after failed writeback - open_by_handle -- open_by_handle_at syscall exercise - stat_test -- statx syscall exercise - t_dir_type -- print directory entries and their file type @@ -30,6 +31,13 @@ af_unix The af_unix program creates an AF_UNIX socket at the given location. +fsync-err + Specialized program for testing how the kernel reports errors that + occur during writeback. Works in conjunction with the dmerror script + in tools/ to write data to a device, and then force it to fail + writeback and test that errors are reported during fsync and cleared + afterward. + open_by_handle The open_by_handle program exercises the open_by_handle_at() system diff --git a/src/Makefile b/src/Makefile index 4ec01975f8f7..b79c4d84d31b 100644 --- a/src/Makefile +++ b/src/Makefile @@ -13,7 +13,7 @@ TARGETS = dirstress fill fill2 getpagesize holes lstat64 \ multi_open_unlink dmiperf unwritten_sync genhashnames t_holes \ t_mmap_writev t_truncate_cmtime dirhash_collide t_rename_overwrite \ holetest t_truncate_self t_mmap_dio af_unix t_mmap_stale_pmd \ - t_mmap_cow_race + t_mmap_cow_race fsync-err 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/fsync-err.c b/src/fsync-err.c new file mode 100644 index 000000000000..cbeb37fb1790 --- /dev/null +++ b/src/fsync-err.c @@ -0,0 +1,161 @@ +/* + * fsync-err.c: test whether writeback errors are reported to all open fds + * and properly cleared as expected after being seen once on each + * + * Copyright (c) 2017: Jeff Layton <jlayton@xxxxxxxxxx> + */ +#include <sys/types.h> +#include <sys/stat.h> +#include <errno.h> +#include <fcntl.h> +#include <stdlib.h> +#include <stdio.h> +#include <string.h> +#include <unistd.h> + +/* + * btrfs has a fixed stripewidth of 64k, so we need to write enough data to + * ensure that we hit both stripes. + * + * FIXME: have the test script pass in the length? + */ +#define BUFSIZE (65 * 1024) + +/* FIXME: should this be tunable */ +#define NUM_FDS 10 + +static void usage() { + fprintf(stderr, "Usage: fsync-err <filename>\n"); +} + +int main(int argc, char **argv) +{ + int fd[NUM_FDS], ret, i; + char *fname, *buf; + + if (argc < 1) { + usage(); + return 1; + } + + /* First argument is filename */ + fname = argv[1]; + + for (i = 0; i < NUM_FDS; ++i) { + fd[i] = open(fname, O_WRONLY | O_CREAT | O_TRUNC, 0644); + if (fd[i] < 0) { + printf("open of fd[%d] failed: %m\n", i); + return 1; + } + } + + buf = malloc(BUFSIZE); + if (!buf) { + printf("malloc failed: %m\n"); + return 1; + } + + memset(buf, 0x7c, BUFSIZE); + + for (i = 0; i < NUM_FDS; ++i) { + ret = write(fd[i], buf, BUFSIZE); + if (ret < 0) { + printf("First write on fd[%d] failed: %m\n", i); + return 1; + } + } + + for (i = 0; i < NUM_FDS; ++i) { + ret = fsync(fd[i]); + if (ret < 0) { + printf("First fsync on fd[%d] failed: %m\n", i); + return 1; + } + } + + /* flip the device to non-working mode */ + ret = system("./tools/dmerror load_error_table"); + if (ret) { + if (WIFEXITED(ret)) + printf("system: program exited: %d\n", + WEXITSTATUS(ret)); + else + printf("system: 0x%x\n", (int)ret); + + return 1; + } + + for (i = 0; i < NUM_FDS; ++i) { + ret = write(fd[i], buf, strlen(buf) + 1); + if (ret < 0) { + printf("Second write on fd[%d] failed: %m\n", i); + return 1; + } + } + + for (i = 0; i < NUM_FDS; ++i) { + ret = fsync(fd[i]); + /* Now, we EXPECT the error! */ + if (ret >= 0) { + printf("Success on second fsync on fd[%d]!\n", i); + return 1; + } + } + + for (i = 0; i < NUM_FDS; ++i) { + ret = fsync(fd[i]); + if (ret < 0) { + /* Now the error should be clear */ + printf("Third fsync on fd[%d] failed: %m\n", i); + return 1; + } + } + + /* flip the device to working mode */ + ret = system("./tools/dmerror load_working_table"); + if (ret) { + if (WIFEXITED(ret)) + printf("system: program exited: %d\n", + WEXITSTATUS(ret)); + else + printf("system: 0x%x\n", (int)ret); + + return 1; + } + + for (i = 0; i < NUM_FDS; ++i) { + ret = fsync(fd[i]); + if (ret < 0) { + /* The error should still be clear */ + printf("fsync after healing device on fd[%d] failed: %m\n", i); + return 1; + } + } + + /* + * reopen each file one at a time to ensure the same inode stays + * in core. fsync each one to make sure we see no errors on a fresh + * open of the inode. + */ + for (i = 0; i < NUM_FDS; ++i) { + ret = close(fd[i]); + if (ret < 0) { + printf("Close of fd[%d] returned unexpected error: %m\n", i); + return 1; + } + fd[i] = open(fname, O_WRONLY | O_CREAT | O_TRUNC, 0644); + if (fd[i] < 0) { + printf("Second open of fd[%d] failed: %m\n", i); + return 1; + } + ret = fsync(fd[i]); + if (ret < 0) { + /* New opens should not return an error */ + printf("First fsync after reopen of fd[%d] failed: %m\n", i); + return 1; + } + } + + printf("Test passed!\n"); + return 0; +} diff --git a/tests/generic/999 b/tests/generic/999 new file mode 100755 index 000000000000..6de143d1149e --- /dev/null +++ b/tests/generic/999 @@ -0,0 +1,76 @@ +#! /bin/bash +# FS QA Test No. 999 +# +# Open a file several times, write to it, fsync on all fds and make sure that +# they all return 0. Change the device to start throwing errors. Write again +# on all fds and fsync on all fds. Ensure that we get errors on all of them. +# Then fsync on all one last time and verify that all return 0. +# +#----------------------------------------------------------------------- +# Copyright (c) 2017, Jeff Layton <jlayton@xxxxxxxxxx> +# +# This program is free software; you can redistribute it and/or +# modify it under the terms of the GNU General Public License as +# published by the Free Software Foundation. +# +# This program is distributed in the hope that it would be useful, +# but WITHOUT ANY WARRANTY; without even the implied warranty of +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +# GNU General Public License for more details. +# +# You should have received a copy of the GNU General Public License +# along with this program; if not, write the Free Software Foundation, +# Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA +#----------------------------------------------------------------------- + +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 -rf $tmp.* $testdir + _dmerror_cleanup +} + +# get standard environment, filters and checks +. ./common/rc +. ./common/filter +. ./common/dmerror + +# real QA test starts here +_supported_os Linux +_require_scratch +_require_logdev +_require_dm_target error +_require_test_program fsync-err + +rm -f $seqres.full + +echo "Format and mount" +$XFS_IO_PROG -d -c "pwrite -S 0x7c -b 1048576 0 $((64 * 1048576))" $SCRATCH_DEV >> $seqres.full +_scratch_mkfs > $seqres.full 2>&1 +_dmerror_init +_dmerror_mount >> $seqres.full 2>&1 +_dmerror_unmount +_dmerror_mount + +_require_fs_space $SCRATCH_MNT 8192 + +testfile=$SCRATCH_MNT/fsync-err-test + +$here/src/fsync-err $testfile + +# success, all done +_dmerror_load_working_table +_dmerror_unmount +_dmerror_cleanup +_repair_scratch_fs >> $seqres.full +status=0 +exit diff --git a/tests/generic/999.out b/tests/generic/999.out new file mode 100644 index 000000000000..2e48492ff6d1 --- /dev/null +++ b/tests/generic/999.out @@ -0,0 +1,3 @@ +QA output created by 999 +Format and mount +Test passed! diff --git a/tests/generic/group b/tests/generic/group index 438c299030f2..39f7b14657f1 100644 --- a/tests/generic/group +++ b/tests/generic/group @@ -440,3 +440,4 @@ 435 auto encrypt 436 auto quick rw 437 auto quick +999 auto quick diff --git a/tools/dmerror b/tools/dmerror new file mode 100755 index 000000000000..4aaf682ee5f9 --- /dev/null +++ b/tools/dmerror @@ -0,0 +1,44 @@ +#!/bin/bash +#----------------------------------------------------------------------- +# Copyright (c) 2017, Jeff Layton <jlayton@xxxxxxxxxx> +# +# This program is free software; you can redistribute it and/or +# modify it under the terms of the GNU General Public License as +# published by the Free Software Foundation. +# +# This program is distributed in the hope that it would be useful, +# but WITHOUT ANY WARRANTY; without even the implied warranty of +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +# GNU General Public License for more details. +# +# You should have received a copy of the GNU General Public License +# along with this program; if not, write the Free Software Foundation, +# Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA +#----------------------------------------------------------------------- + +. ./common/config +. ./common/dmerror + +_dmerror_setup + +case $1 in +cleanup) + _dmerror_cleanup + ;; +init) + _dmerror_init + ;; +load_error_table) + _dmerror_load_error_table + ;; +load_working_table) + _dmerror_load_working_table + ;; +*) + echo "Usage: $0 {init|cleanup|load_error_table|load_working_table}" + exit 1 + ;; +esac + +status=0 +exit -- 2.9.4