mirror_zfs/tests/zfs-tests/cmd/truncate_test.c

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Fix truncate(2) mtime and ctime handling On Linux, ftruncate(2) always changes the file timestamps, even if the file size is not changed. However, in case of a successfull truncate(2), the timestamps are updated only if the file size changes. This translates to the VFS calling the ZFS Posix Layer "setattr" function (zpl_setattr) with ATTR_MTIME and ATTR_CTIME unconditionally set on the iattr mask only when doing a ftruncate(2), while the truncate(2) is left to the filesystem implementation to be dealt with. This behaviour is consistent with POSIX:2004/SUSv3 specifications where there's no explicit requirement for file size changes to update the timestamps only for ftruncate(2): http://pubs.opengroup.org/onlinepubs/009695399/functions/truncate.html http://pubs.opengroup.org/onlinepubs/009695399/functions/ftruncate.html This has been later updated in POSIX:2008/SUSv4 where, for both truncate(2)/ftruncate(2), there's no mention of this size change requirement: http://austingroupbugs.net/view.php?id=489 http://pubs.opengroup.org/onlinepubs/9699919799/functions/truncate.html http://pubs.opengroup.org/onlinepubs/9699919799/functions/ftruncate.html Unfortunately the Linux VFS is still calling into the ZPL without ATTR_MTIME/ATTR_CTIME set in the truncate(2) case: we fix this by explicitly updating the timestamps when detecting the ATTR_SIZE bit, which is always set in do_truncate(), on the iattr mask. Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov> Signed-off-by: loli10K <ezomori.nozomu@gmail.com> Closes #6811 Closes #6819
2017-11-13 20:24:26 +03:00
/*
* This file and its contents are supplied under the terms of the
* Common Development and Distribution License ("CDDL"), version 1.0.
* You may only use this file in accordance with the terms of version
* 1.0 of the CDDL.
*
* A full copy of the text of the CDDL should have accompanied this
* source. A copy of the CDDL is also available via the Internet at
* http://www.illumos.org/license/CDDL.
*/
/*
* Copyright (c) 2012, 2014 by Delphix. All rights reserved.
* Copyright 2017, loli10K <ezomori.nozomu@gmail.com>. All rights reserved.
*/
#include <fcntl.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#define FSIZE 256*1024*1024
static long fsize = FSIZE;
static int errflag = 0;
static char *filename = NULL;
static int ftruncflag = 0;
static void parse_options(int argc, char *argv[]);
static void
usage(char *execname)
{
(void) fprintf(stderr,
"usage: %s [-s filesize] [-f] /path/to/file\n", execname);
(void) exit(1);
}
int
main(int argc, char *argv[])
{
int fd;
parse_options(argc, argv);
if (ftruncflag) {
fd = open(filename, O_RDWR|O_CREAT, 0666);
if (fd < 0) {
perror("open");
return (1);
}
if (ftruncate(fd, fsize) < 0) {
perror("ftruncate");
return (1);
}
if (close(fd)) {
perror("close");
return (1);
}
} else {
if (truncate(filename, fsize) < 0) {
perror("truncate");
return (1);
}
}
return (0);
}
static void
parse_options(int argc, char *argv[])
{
int c;
extern char *optarg;
extern int optind, optopt;
while ((c = getopt(argc, argv, "s:f")) != -1) {
switch (c) {
case 's':
fsize = atoi(optarg);
break;
case 'f':
ftruncflag++;
break;
case ':':
(void) fprintf(stderr,
"Option -%c requires an operand\n", optopt);
errflag++;
break;
}
if (errflag) {
(void) usage(argv[0]);
}
}
if (argc <= optind) {
(void) fprintf(stderr, "No filename specified\n");
usage(argv[0]);
}
filename = argv[optind];
}