On Fri, Aug 27, 2021 at 05:06:03PM +0200, Andreas Gruenbacher wrote: > Here's an update of a test case I'm trying to get merged since May. > Please have a look; I'm tired of dragging this along. > > Thanks, > Andreas > > -- > > Some filesystems have problems when the buffer passed to read or write > is memory-mapped to the file being read from or written to, and the > buffer needs to be faulted in during the read or write. That's not > common, but filesystems are still required to cope with it, and if they > fail this test, then they will also fail more complex scenarios that > involve multiple files. > > Signed-off-by: Andreas Gruenbacher <agruenba@xxxxxxxxxx> > --- > src/Makefile | 2 +- > src/mmap-rw-fault.c | 176 ++++++++++++++++++++++++++++++++++++++++++ > tests/generic/646 | 27 +++++++ > tests/generic/646.out | 2 + > 4 files changed, 206 insertions(+), 1 deletion(-) > create mode 100644 src/mmap-rw-fault.c > create mode 100755 tests/generic/646 > create mode 100644 tests/generic/646.out > > diff --git a/src/Makefile b/src/Makefile > index 884bd86a..25ab061d 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 > + t_mmap_writev_overlap checkpoint_journal mmap-rw-fault > > 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/mmap-rw-fault.c b/src/mmap-rw-fault.c > new file mode 100644 > index 00000000..244d2cb6 > --- /dev/null > +++ b/src/mmap-rw-fault.c The generated binary needs a gitignore entry. > @@ -0,0 +1,176 @@ > +/* Trigger mmap page faults in the same file during pread and pwrite. */ Needs a SPDX header and a copyright statement. > + > +#ifndef _GNU_SOURCE > +#define _GNU_SOURCE /* to get definition of O_DIRECT flag. */ > +#endif > + > +#include <sys/types.h> > +#include <sys/stat.h> > +#include <sys/mman.h> > +#include <fcntl.h> > +#include <unistd.h> > +#include <stdlib.h> > +#include <stdio.h> > +#include <string.h> > +#include <errno.h> > +#include <err.h> <now we skip to main> > +int main(int argc, char *argv[]) > +{ > + if (argc != 2) > + errx(1, "no test filename argument given"); > + filename = argv[1]; > + > + page_size = ret = sysconf(_SC_PAGE_SIZE); > + if (ret == -1) > + err(1, NULL); > + > + ret = posix_memalign(&page, page_size, page_size); > + if (ret) { > + errno = ENOMEM; > + err(1, NULL); > + } > + > + /* > + * Make sure page faults during pread are handled correctly. > + */ These test reading from page 1 into (mmap) page 0, right? > + init('a', O_RDWR); > + ret = do_read(fd, addr, page_size, page_size); > + if (ret != page_size) > + err(1, "pread %s: %ld != %u", filename, ret, page_size); > + if (memcmp(addr, page, page_size)) > + errx(1, "pread is broken"); > + done(); > + > + init('b', O_RDWR | O_DIRECT); > + ret = do_read(fd, addr, page_size, page_size); > + if (ret != page_size) > + err(1, "pread %s (O_DIRECT): %ld != %u", filename, ret, page_size); > + if (memcmp(addr, page, page_size)) > + errx(1, "pread (D_DIRECT) is broken"); > + done(); > + > + /* > + * Make sure page faults during pwrite are handled correctly. > + */ ...and writing from (mmap) page 1 into page 0? > + init('c', O_RDWR); > + ret = do_write(fd, addr + page_size, page_size, 0); > + if (ret != page_size) > + err(1, "pwrite %s: %ld != %u", filename, ret, page_size); > + if (memcmp(addr, page, page_size)) > + errx(1, "pwrite is broken"); > + done(); > + > + init('d', O_RDWR | O_DIRECT); > + ret = do_write(fd, addr + page_size, page_size, 0); > + if (ret != page_size) > + err(1, "pwrite %s (O_DIRECT): %ld != %u", filename, ret, page_size); > + if (memcmp(addr, page, page_size)) > + errx(1, "pwrite (O_DIRECT) is broken"); > + done(); > + > + /* > + * Reading from a hole takes a different code path in the kernel. > + */ ...and finally we test direct reading from page 0 into (mmap) page 0? If that's correct, then this looks good to me, modulo the license nit at the top. > + init('e', O_RDWR | O_DIRECT); > + ret = do_read(fd, addr, page_size, 0); > + if (ret != page_size) > + err(1, "pread %s (O_DIRECT) from hole: %ld != %u", filename, ret, page_size); > + memset(page, 0, page_size); > + if (memcmp(addr, page, page_size)) > + errx(1, "pread (D_DIRECT) from hole is broken"); > + done(); > + > + if (unlink(filename)) > + err(1, "unlink %s", filename); > + > + return 0; > +} > diff --git a/tests/generic/646 b/tests/generic/646 > new file mode 100755 > index 00000000..57d8c13d > --- /dev/null > +++ b/tests/generic/646 > @@ -0,0 +1,27 @@ > +#! /bin/bash > +# SPDX-License-Identifier: GPL-2.0 > +# Copyright (c) 2021 Red Hat, Inc. All Rights Reserved. > +# > +# FS QA Test 646 > +# > +# Trigger mmap page faults in the same file during pread and pwrite > +# > +. ./common/preamble > +_begin_fstest auto quick > + > +# get standard environment, filters and checks > +. ./common/rc > +. ./common/filter > + > +# real QA test starts here > + > +_supported_fs generic > +_require_test > +_require_test_program mmap-rw-fault > + > +echo "Silence is golden" > + > +$here/src/mmap-rw-fault $TEST_DIR/mmap-rw-fault.tmp _cleanup should clean up the tempfile if the C program crashes, right? Or use O_TMPFILE and let the kernel clean up the file for you. --D > + > +status=$? > +exit > diff --git a/tests/generic/646.out b/tests/generic/646.out > new file mode 100644 > index 00000000..8357006e > --- /dev/null > +++ b/tests/generic/646.out > @@ -0,0 +1,2 @@ > +QA output created by 646 > +Silence is golden > -- > 2.26.3 >