/*
* fallocate - utility to use the fallocate system call
*
* Copyright (C) 2008-2009 Red Hat, Inc. All rights reserved.
* Written by Eric Sandeen <sandeen@redhat.com>
* Karel Zak <kzak@redhat.com>
*
* cvtnum routine taken from xfsprogs,
* Copyright (c) 2003-2005 Silicon Graphics, Inc.
*
* 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 to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/mman.h>
#include <ctype.h>
#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <getopt.h>
#include <limits.h>
#include <string.h>
#ifndef HAVE_FALLOCATE
# include <sys/syscall.h>
#endif
#if defined(HAVE_LINUX_FALLOC_H) && \
(!defined(FALLOC_FL_KEEP_SIZE) || !defined(FALLOC_FL_PUNCH_HOLE) || \
!defined(FALLOC_FL_COLLAPSE_RANGE) || !defined(FALLOC_FL_ZERO_RANGE))
# include <linux/falloc.h> /* non-libc fallback for FALLOC_FL_* flags */
#endif
#ifndef FALLOC_FL_KEEP_SIZE
# define FALLOC_FL_KEEP_SIZE 0x1
#endif
#ifndef FALLOC_FL_PUNCH_HOLE
# define FALLOC_FL_PUNCH_HOLE 0x2
#endif
#ifndef FALLOC_FL_COLLAPSE_RANGE
# define FALLOC_FL_COLLAPSE_RANGE 0x8
#endif
#ifndef FALLOC_FL_ZERO_RANGE
# define FALLOC_FL_ZERO_RANGE 0x10
#endif
#include "nls.h"
#include "strutils.h"
#include "c.h"
#include "closestream.h"
#include "xalloc.h"
#include "optutils.h"
static int verbose;
static char *filename;
static void __attribute__((__noreturn__)) usage(FILE *out)
{
fputs(USAGE_HEADER, out);
fprintf(out,
_(" %s [options] <filename>\n"), program_invocation_short_name);
fputs(USAGE_OPTIONS, out);
fputs(_(" -c, --collapse-range remove a range from the file\n"), out);
fputs(_(" -d, --dig-holes detect zeroes and replace with holes\n"), out);
fputs(_(" -l, --length <num> length for range operations, in bytes\n"), out);
fputs(_(" -n, --keep-size maintain the apparent size of the file\n"), out);
fputs(_(" -o, --offset <num> offset for range operations, in bytes\n"), out);
fputs(_(" -p, --punch-hole replace a range with a hole (implies -n)\n"), out);
fputs(_(" -z, --zero-range zero and ensure allocation of a range\n"), out);
fputs(_(" -v, --verbose verbose mode\n"), out);
fputs(USAGE_SEPARATOR, out);
fputs(USAGE_HELP, out);
fputs(USAGE_VERSION, out);
fprintf(out, USAGE_MAN_TAIL("fallocate(1)"));
exit(out == stderr ? EXIT_FAILURE : EXIT_SUCCESS);
}
static loff_t cvtnum(char *s)
{
uintmax_t x;
if (strtosize(s, &x))
return -1LL;
return x;
}
static void xfallocate(int fd, int mode, off_t offset, off_t length)
{
int error;
#ifdef HAVE_FALLOCATE
error = fallocate(fd, mode, offset, length);
#else
error = syscall(SYS_fallocate, fd, mode, offset, length);
#endif
/*
* EOPNOTSUPP: The FALLOC_FL_KEEP_SIZE is unsupported
* ENOSYS: The filesystem does not support sys_fallocate
*/
if (error < 0) {
if ((mode & FALLOC_FL_KEEP_SIZE) && errno == EOPNOTSUPP)
errx(EXIT_FAILURE, _("keep size mode (-n option) unsupported"));
err(EXIT_FAILURE, _("fallocate failed"));
}
}
static int skip_hole(int fd, off_t *off)
{
off_t newoff;
errno = 0;
newoff = lseek(fd, *off, SEEK_DATA);
/* ENXIO means that there is no more data -- probably sparse hole at
* the end of the file */
if (newoff < 0 && errno == ENXIO)
return 1;
if (newoff > *off) {
*off = newoff;
return 0; /* success */
}
return -1; /* no hole */
}
/* The real buffer size has to be bufsize + sizeof(uintptr_t) */
static int is_nul(void *buf, size_t bufsize)
{
typedef uintptr_t word;
void const *vp;
char const *cbuf = buf, *cp;
word const *wp = buf;
/* set sentinel */
memset((char *) buf + bufsize, '\1', sizeof(word));
/* Find first nonzero *word*, or the word with the sentinel. */
while (*wp++ == 0)
continue;
/* Find the first nonzero *byte*, or the sentinel. */
vp = wp - 1;
cp = vp;
while (*cp++ == 0)
continue;
return cbuf + bufsize < cp;
}
static void dig_holes(int fd, off_t off, off_t len)
{
off_t end = len ? off + len : 0;
off_t hole_start = 0, hole_sz = 0;
uintmax_t ct = 0;
size_t bufsz;
char *buf;
struct stat st;
#if defined(POSIX_FADV_SEQUENTIAL) && defined(HAVE_POSIX_FADVISE)
off_t cache_start = off;
/*
* We don't want to call POSIX_FADV_DONTNEED to discard cached
* data in PAGE_SIZE steps. IMHO it's overkill (too many syscalls).
*
* Let's assume that 1MiB (on system with 4K page size) is just
* a good compromise.
* -- kzak Feb-2014
*/
const size_t cachesz = getpagesize() * 256;
#endif
if (fstat(fd, &st) != 0)
err(EXIT_FAILURE, _("stat failed %s"), filename);
bufsz = st.st_blksize;
if (lseek(fd, off, SEEK_SET) < 0)
err(EXIT_FAILURE, _("seek on %s failed"), filename);
/* buffer + extra space for is_nul() sentinel */
buf = xmalloc(bufsz + sizeof(uintptr_t));
#if defined(POSIX_FADV_SEQUENTIAL) && defined(HAVE_POSIX_FADVISE)
posix_fadvise(fd, off, 0, POSIX_FADV_SEQUENTIAL);
#endif
while (end == 0 || off < end) {
ssize_t rsz;
rsz = pread(fd, buf, bufsz, off);
if (rsz < 0 && errno)
err(EXIT_FAILURE, _("%s: read failed"), filename);
if (end && rsz > 0 && off > end - rsz)
rsz = end - off;
if (rsz <= 0)
break;
if (is_nul(buf, rsz)) {
if (!hole_sz) { /* new hole detected */
int rc = skip_hole(fd, &off);
if (rc == 0)
continue; /* hole skipped */
else if (rc == 1)
break; /* end of file */
hole_start = off;
}
hole_sz += rsz;
} else if (hole_sz) {
xfallocate(fd, FALLOC_FL_PUNCH_HOLE|FALLOC_FL_KEEP_SIZE,
hole_start, hole_sz);
ct += hole_sz;
hole_sz = hole_start = 0;
}
#if defined(POSIX_FADV_DONTNEED) && defined(HAVE_POSIX_FADVISE)
/* discard cached data */
if (off - cache_start > (off_t) cachesz) {
size_t clen = off - cache_start;
clen = (clen / cachesz) * cachesz;
posix_fadvise(fd, cache_start, clen, POSIX_FADV_DONTNEED);
cache_start = cache_start + clen;
}
#endif
off += rsz;
}
if (hole_sz) {
xfallocate(fd, FALLOC_FL_PUNCH_HOLE|FALLOC_FL_KEEP_SIZE,
hole_start, hole_sz);
ct += hole_sz;
}
free(buf);
if (verbose) {
char *str = size_to_human_string(SIZE_SUFFIX_3LETTER | SIZE_SUFFIX_SPACE, ct);
fprintf(stdout, _("%s: %s (%ju bytes) converted to sparse holes.\n"),
filename, str, ct);
free(str);
}
}
int main(int argc, char **argv)
{
int c;
int fd;
int mode = 0;
int dig = 0;
loff_t length = -2LL;
loff_t offset = 0;
static const struct option longopts[] = {
{ "help", 0, 0, 'h' },
{ "version", 0, 0, 'V' },
{ "keep-size", 0, 0, 'n' },
{ "punch-hole", 0, 0, 'p' },
{ "collapse-range", 0, 0, 'c' },
{ "dig-holes", 0, 0, 'd' },
{ "zero-range", 0, 0, 'z' },
{ "offset", 1, 0, 'o' },
{ "length", 1, 0, 'l' },
{ "verbose", 0, 0, 'v' },
{ NULL, 0, 0, 0 }
};
static const ul_excl_t excl[] = { /* rows and cols in in ASCII order */
{ 'c', 'd', 'p', 'z' },
{ 'c', 'n' },
{ 0 }
};
int excl_st[ARRAY_SIZE(excl)] = UL_EXCL_STATUS_INIT;
setlocale(LC_ALL, "");
bindtextdomain(PACKAGE, LOCALEDIR);
textdomain(PACKAGE);
atexit(close_stdout);
while ((c = getopt_long(argc, argv, "hvVncpdzl:o:", longopts, NULL))
!= -1) {
err_exclusive_options(c, longopts, excl, excl_st);
switch(c) {
case 'h':
usage(stdout);
break;
case 'c':
mode |= FALLOC_FL_COLLAPSE_RANGE;
break;
case 'd':
dig = 1;
break;
case 'l':
length = cvtnum(optarg);
break;
case 'n':
mode |= FALLOC_FL_KEEP_SIZE;
break;
case 'o':
offset = cvtnum(optarg);
break;
case 'p':
mode |= FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE;
break;
case 'z':
mode |= FALLOC_FL_ZERO_RANGE;
break;
case 'v':
verbose++;
break;
case 'V':
printf(UTIL_LINUX_VERSION);
return EXIT_SUCCESS;
default:
usage(stderr);
break;
}
}
if (optind == argc)
errx(EXIT_FAILURE, _("no filename specified."));
filename = argv[optind++];
if (optind != argc)
errx(EXIT_FAILURE, _("unexpected number of arguments"));
if (dig) {
/* for --dig-holes the default is analyze all file */
if (length == -2LL)
length = 0;
if (length < 0)
errx(EXIT_FAILURE, _("invalid length value specified"));
} else {
/* it's safer to require the range specification (--length --offset) */
if (length == -2LL)
errx(EXIT_FAILURE, _("no length argument specified"));
if (length <= 0)
errx(EXIT_FAILURE, _("invalid length value specified"));
}
if (offset < 0)
errx(EXIT_FAILURE, _("invalid offset value specified"));
/* O_CREAT makes sense only for the default fallocate(2) behavior
* when mode is no specified and new space is allocated */
fd = open(filename, O_RDWR | (!dig && !mode ? O_CREAT : 0), 0644);
if (fd < 0)
err(EXIT_FAILURE, _("cannot open %s"), filename);
if (dig)
dig_holes(fd, offset, length);
else
xfallocate(fd, mode, offset, length);
if (close_fd(fd) != 0)
err(EXIT_FAILURE, _("write failed: %s"), filename);
return EXIT_SUCCESS;
}
