The fallocate(1) utility is used to preallocate blocks to a file. This can be useful for virtual images, database files, testing, etc. Normally we'd hope that various tools will start using preallocation internally, but until then such a utility may be useful, and could be scripted as well. The original Eric's version is available at: http://thread.gmane.org/gmane.linux.utilities.util-linux-ng/2490 This version: - checks for fallocate glibc function and kernel syscall - does not provide a fallback and does not call posix_fallocate() - adds long options - uses err.h for errro messages - adds NLS support - cleanups man page Co-Author: Eric Sandeen <sandeen@xxxxxxxxxx> Signed-off-by: Eric Sandeen <sandeen@xxxxxxxxxx> Signed-off-by: Karel Zak <kzak@xxxxxxxxxx> --- AUTHORS | 1 + configure.ac | 3 + sys-utils/.gitignore | 1 + sys-utils/Makefile.am | 5 ++ sys-utils/fallocate.1 | 51 ++++++++++++++ sys-utils/fallocate.c | 173 +++++++++++++++++++++++++++++++++++++++++++++++++ 6 files changed, 234 insertions(+), 0 deletions(-) create mode 100644 sys-utils/fallocate.1 create mode 100644 sys-utils/fallocate.c diff --git a/AUTHORS b/AUTHORS index 1aaec44..b280bb7 100644 --- a/AUTHORS +++ b/AUTHORS @@ -31,6 +31,7 @@ AUTHORS (merged projects & commands): simpleinit: Richard Gooch <rgooch@xxxxxxxxxxxxx> switch_root: Peter Jones <pjones@xxxxxxxxxx> Jeremy Katz <katzj@xxxxxxxxxx> + fallocate: Eric Sandeen <sandeen@xxxxxxxxxx> CONTRIBUTORS: diff --git a/configure.ac b/configure.ac index 8999826..f80f7b7 100644 --- a/configure.ac +++ b/configure.ac @@ -554,6 +554,9 @@ UTIL_CHECK_SYSCALL([ioprio_get], [sh*], [289], [x86_64*], [252]) +dnl fallocate could be available as libc function or as syscall only +UTIL_CHECK_SYSCALL([fallocate]) +AC_CHECK_FUNCS([fallocate]) AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[ #include <time.h> diff --git a/sys-utils/.gitignore b/sys-utils/.gitignore index 6f0be71..2cc2dee 100644 --- a/sys-utils/.gitignore +++ b/sys-utils/.gitignore @@ -2,6 +2,7 @@ arch ctrlaltdel cytune dmesg +fallocate flock i386.8 ia64.8 diff --git a/sys-utils/Makefile.am b/sys-utils/Makefile.am index 19ecccc..e6f7629 100644 --- a/sys-utils/Makefile.am +++ b/sys-utils/Makefile.am @@ -23,6 +23,11 @@ tunelp_SOURCES = tunelp.c lp.h info_TEXINFOS = ipc.texi +if HAVE_FALLOCATE +usrbin_exec_PROGRAMS += fallocate +dist_man_MANS += fallocate.1 +endif + if HAVE_PIVOT_ROOT sbin_PROGRAMS += pivot_root dist_man_MANS += pivot_root.8 diff --git a/sys-utils/fallocate.1 b/sys-utils/fallocate.1 new file mode 100644 index 0000000..00e973c --- /dev/null +++ b/sys-utils/fallocate.1 @@ -0,0 +1,51 @@ +.\" -*- nroff -*- +.TH FALLOCATE 1 "Jul 2009" "Version 1.0" +.SH NAME +fallocate \- preallocate space to a file. +.SH SYNOPSIS +.B fallocate +.RB [ \-n ] +.RB [ \-o +.IR offset ] +.B \-l +.IR length +.I filename +.SH DESCRIPTION +.B fallocate +is used to preallocate blocks to a file. For filesystems which support the +fallocate system call, this is done quickly by allocating blocks and marking +them as uninitialized, requiring no IO to the data blocks. This is much faster +than creating a file by filling it with zeros. +.PP +As of the Linux Kernel v2.6.31, the fallocate system call is supported by the +btrfs, ext4, ocfs2, and xfs filesystems. +.PP +The exit code returned by +.B fallocate +is 0 on success and 1 on failure. +.PP +.SH OPTIONS +.IP "\fB\-h, \-\-help\fP" +Print help and exit. +.IP "\fB\-n, \-\-keep-size\fP" +Do not modify the apparent length of the file. This may effectively allocate +blocks past EOF, which can be removed with a truncate. +.IP "\fB\-o, \-\-offset\fP \fIoffset\fP +Specifies the beginning offset of the allocation, in bytes. Suffixes of k, m, +g, t, p, e may be specified to denote KiB, MiB, GiB, etc. +.IP "\fB\-l, \-\-length\fP \fIlength\fP +Specifies the length of the allocation, in bytes. Suffixes of k, m, g, t, p, e +may be specified to denote KiB, MiB, GiB, etc. +.SH AUTHORS +.nf +Eric Sandeen <sandeen@xxxxxxxxxx> +Karel Zak <kzak@xxxxxxxxxx> +.fi +.SH SEE ALSO +.BR fallocate (2), +.BR posix_fallocate (3), +.BR truncate (1) +.SH AVAILABILITY +The fallocate command is part of the util-linux-ng package and is available from +ftp://ftp.kernel.org/pub/linux/utils/util-linux-ng/. + diff --git a/sys-utils/fallocate.c b/sys-utils/fallocate.c new file mode 100644 index 0000000..66e9764 --- /dev/null +++ b/sys-utils/fallocate.c @@ -0,0 +1,173 @@ +/* + * fallocate - utility to use the fallocate system call + * + * Copyright (C) 2008-2009 Red Hat, Inc. All rights reserved. + * Written by Eric Sandeen <sandeen@xxxxxxxxxx> + * Karel Zak <kzak@xxxxxxxxxx> + * + * 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + */ +#include <sys/stat.h> +#include <sys/types.h> +#include <ctype.h> +#include <errno.h> +#include <fcntl.h> +#include <stdio.h> +#include <stdlib.h> +#include <unistd.h> +#include <getopt.h> +#include <err.h> + +#ifndef HAVE_FALLOCATE +# include <sys/syscall.h> +#endif + +#include <linux/falloc.h> /* for FALLOC_FL_* flags */ + +#include "nls.h" + + +static void __attribute__((__noreturn__)) usage(FILE *out) +{ + fprintf(out, _("Usage: %s [options] <filename>\n\nOptions:\n"), + program_invocation_short_name); + + fprintf(out, _( + " -h, --help this help\n" + " -n, --keep-size don't modify the length of the file\n" + " -o, --offset <num> offset of the allocation, in bytes\n" + " -l, --length <num> length of the allocation, in bytes\n")); + + fprintf(out, _("\nFor more information see fallocate(1).\n")); + + exit(out == stderr ? EXIT_FAILURE : EXIT_SUCCESS); +} + +#define EXABYTES(x) ((x) << 60) +#define PETABYTES(x) ((x) << 50) +#define TERABYTES(x) ((x) << 40) +#define GIGABYTES(x) ((x) << 30) +#define MEGABYTES(x) ((x) << 20) +#define KILOBYTES(x) ((x) << 10) + +static loff_t cvtnum(char *s) +{ + loff_t i; + char *sp; + + i = strtoll(s, &sp, 0); + if (i == 0 && sp == s) + return -1LL; + if (*sp == '\0') + return i; + if (sp[1] != '\0') + return -1LL; + + switch (tolower(*sp)) { + case 'k': + return KILOBYTES(i); + case 'm': + return MEGABYTES(i); + case 'g': + return GIGABYTES(i); + case 't': + return TERABYTES(i); + case 'p': + return PETABYTES(i); + case 'e': + return EXABYTES(i); + } + + return -1LL; +} + +int main(int argc, char **argv) +{ + char *fname; + int c; + int error; + int fd; + int mode = 0; + loff_t length = -2LL; + loff_t offset = 0; + + struct option longopts[] = { + { "help", 0, 0, 'h' }, + { "keep-size", 0, 0, 'n' }, + { "offset", 1, 0, 'o' }, + { "lenght", 1, 0, 'l' }, + { NULL, 0, 0, 0 } + }; + + setlocale(LC_ALL, ""); + bindtextdomain(PACKAGE, LOCALEDIR); + textdomain(PACKAGE); + + while ((c = getopt_long(argc, argv, "hnl:o:", longopts, NULL)) != -1) { + switch(c) { + case 'h': + usage(stdout); + break; + case 'n': + mode |= FALLOC_FL_KEEP_SIZE; + break; + case 'l': + length = cvtnum(optarg); + break; + case 'o': + offset = cvtnum(optarg); + break; + default: + usage(stderr); + break; + } + } + + 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")); + if (optind == argc) + errx(EXIT_FAILURE, _("no filename specified.")); + + fname = argv[optind++]; + + fd = open(fname, O_WRONLY|O_CREAT, 0644); + if (fd < 0) + err(EXIT_FAILURE, _("%s: open failed"), fname); + +#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, _("%s: fallocate failed"), fname); + } + + close(fd); + return EXIT_SUCCESS; +} -- 1.6.2.5 -- To unsubscribe from this list: send the line "unsubscribe util-linux-ng" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
