From: Alexey Dobriyan <adobriyan@xxxxxxxxx> Subject: tmpfs: test link accounting with O_TMPFILE Mount tmpfs with "nr_inodes=3" for easy check. Link: http://lkml.kernel.org/r/20190219215016.GA20084@avx2 Signed-off-by: Alexey Dobriyan <adobriyan@xxxxxxxxx> Reviewed-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> Cc: Darrick J. Wong <darrick.wong@xxxxxxxxxx> Cc: Hugh Dickins <hughd@xxxxxxxxxx> Cc: Matej Kupljen <matej.kupljen@xxxxxxxxx> Cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- tools/testing/selftests/Makefile | 1 tools/testing/selftests/tmpfs/.gitignore | 1 tools/testing/selftests/tmpfs/Makefile | 7 + tools/testing/selftests/tmpfs/bug-link-o-tmpfile.c | 67 +++++++++++ 4 files changed, 76 insertions(+) --- a/tools/testing/selftests/Makefile~tmpfs-test-link-accounting-with-o_tmpfile +++ a/tools/testing/selftests/Makefile @@ -48,6 +48,7 @@ TARGETS += sysctl ifneq (1, $(quicktest)) TARGETS += timers endif +TARGETS += tmpfs TARGETS += user TARGETS += vm TARGETS += x86 --- /dev/null +++ a/tools/testing/selftests/tmpfs/bug-link-o-tmpfile.c @@ -0,0 +1,67 @@ +/* + * Copyright (c) 2019 Alexey Dobriyan <adobriyan@xxxxxxxxx> + * + * Permission to use, copy, modify, and distribute this software for any + * purpose with or without fee is hereby granted, provided that the above + * copyright notice and this permission notice appear in all copies. + * + * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES + * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF + * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR + * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES + * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN + * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF + * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. + */ +/* Test that open(O_TMPFILE), linkat() doesn't screw accounting. */ +#include <errno.h> +#include <sched.h> +#include <stdio.h> +#include <sys/types.h> +#include <sys/stat.h> +#include <fcntl.h> +#include <sys/mount.h> +#include <unistd.h> + +int main(void) +{ + int fd; + + if (unshare(CLONE_NEWNS) == -1) { + if (errno == ENOSYS || errno == EPERM) { + fprintf(stderr, "error: unshare, errno %d\n", errno); + return 4; + } + fprintf(stderr, "error: unshare, errno %d\n", errno); + return 1; + } + if (mount(NULL, "/", NULL, MS_PRIVATE|MS_REC, NULL) == -1) { + fprintf(stderr, "error: mount '/', errno %d\n", errno); + return 1; + } + + /* Our heroes: 1 root inode, 1 O_TMPFILE inode, 1 permanent inode. */ + if (mount(NULL, "/tmp", "tmpfs", 0, "nr_inodes=3") == -1) { + fprintf(stderr, "error: mount tmpfs, errno %d\n", errno); + return 1; + } + + fd = openat(AT_FDCWD, "/tmp", O_WRONLY|O_TMPFILE, 0600); + if (fd == -1) { + fprintf(stderr, "error: open 1, errno %d\n", errno); + return 1; + } + if (linkat(fd, "", AT_FDCWD, "/tmp/1", AT_EMPTY_PATH) == -1) { + fprintf(stderr, "error: linkat, errno %d\n", errno); + return 1; + } + close(fd); + + fd = openat(AT_FDCWD, "/tmp", O_WRONLY|O_TMPFILE, 0600); + if (fd == -1) { + fprintf(stderr, "error: open 2, errno %d\n", errno); + return 1; + } + + return 0; +} --- /dev/null +++ a/tools/testing/selftests/tmpfs/.gitignore @@ -0,0 +1 @@ +/bug-link-o-tmpfile --- /dev/null +++ a/tools/testing/selftests/tmpfs/Makefile @@ -0,0 +1,7 @@ +CFLAGS += -Wall -O2 +CFLAGS += -D_GNU_SOURCE + +TEST_GEN_PROGS := +TEST_GEN_PROGS += bug-link-o-tmpfile + +include ../lib.mk _
