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Refactor fallocate(1)

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1) Simplify the manpage. Just refer to fallocate(2) and stop trying
   to list supported file systems. This can change and everbody
   with common sense can bring up the relevant manpages of a given
   operating system himself.
   Use the num-semantics.
2) Use estrtonum() instead of estrtol().
3) Allow multiple arguments.
This commit is contained in:
FRIGN 2015-09-11 00:27:29 +02:00 committed by sin
parent 90c7584089
commit e3b20bbda0
3 changed files with 49 additions and 26 deletions
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34
fallocate.1
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@ -1,27 +1,33 @@
.Dd February 2, 2015 .Dd September 11, 2015
.Dt FALLOCATE 1 .Dt FALLOCATE 1
.Os ubase .Os ubase
.Sh NAME .Sh NAME
.Nm fallocate .Nm fallocate
.Nd preallocate blocks to a file .Nd reallocate files
.Sh SYNOPSIS .Sh SYNOPSIS
.Nm .Nm
.Op Fl o Ar offset .Op Fl o Ar num
.Fl l Ar length Ar file .Fl l Ar num
.Ar file ...
.Sh DESCRIPTION .Sh DESCRIPTION
.Nm .Nm
preallocates blocks to a file. Only certain filesystems support the if necessary creates and reallocates each
.Xr fallocate 2 .Ar file
system call. This is a very fast operation to allocate uninitialized blocks resulting in expansion or truncation.
in a file without doing any IO. As of the Linux kernel v2.6.31, the .sp
.Xr fallocate 2 Given the filesystem supports
system call is supported by the btrfs, ext4, ocfs2, and xfs filesystems. .Xr fallocate 2 ,
it is a very fast method of reallocation.
.Sh OPTIONS .Sh OPTIONS
.Bl -tag -width Ds .Bl -tag -width Ds
.It Fl l Ar length .It Fl l Ar num
Specifies the length of the allocation, in bytes. Allocate
.It Fl o .Ar num
Specifies the beginning offset of the allocation, in bytes. bytes.
.It Fl o Ar num
Offset allocation by
.Ar num
bytes.
.El .El
.Sh SEE ALSO .Sh SEE ALSO
.Xr fallocate 2 .Xr fallocate 2

33
fallocate.c
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@ -2,6 +2,8 @@
#include <sys/stat.h> #include <sys/stat.h>
#include <fcntl.h> #include <fcntl.h>
#include <limits.h>
#include <stdint.h>
#include <stdio.h> #include <stdio.h>
#include <stdlib.h> #include <stdlib.h>
#include <unistd.h> #include <unistd.h>
@ -11,36 +13,43 @@
static void static void
usage(void) usage(void)
{ {
eprintf("usage: %s [-o offset] -l length file\n", argv0); eprintf("usage: %s [-o num] -l num file ...\n", argv0);
} }
int int
main(int argc, char *argv[]) main(int argc, char *argv[])
{ {
int fd; int fd, ret = 0;
off_t size = 0, offset = 0; off_t size = 0, offset = 0;
ARGBEGIN { ARGBEGIN {
case 'l': case 'l':
size = estrtol(EARGF(usage()), 10); size = estrtonum(EARGF(usage()), 1, MIN(LLONG_MAX, SIZE_MAX));
break; break;
case 'o': case 'o':
offset = estrtol(EARGF(usage()), 10); offset = estrtonum(EARGF(usage()), 0, MIN(LLONG_MAX, SIZE_MAX));
break; break;
default: default:
usage(); usage();
} ARGEND; } ARGEND;
if (argc != 1 || !size) if (!argc || !size)
usage(); usage();
fd = open(argv[0], O_RDWR | O_CREAT, 0644); for (; *argv; argc--, argv++) {
if (fd < 0) if ((fd = open(*argv, O_RDWR | O_CREAT, 0644)) < 0) {
eprintf("open %s:", argv[0]); weprintf("open %s:", *argv);
ret = 1;
} else if (posix_fallocate(fd, offset, size) < 0) {
weprintf("posix_fallocate %s:", *argv);
ret = 1;
}
if (posix_fallocate(fd, offset, size) < 0) if (fd >= 0 && close(fd) < 0) {
eprintf("posix_fallocate:"); weprintf("close %s:", *argv);
ret = 1;
}
}
close(fd); return ret;
return 0;
} }

8
util.h
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@ -2,6 +2,14 @@
#include "arg.h" #include "arg.h"
#define UTF8_POINT(c) (((c) & 0xc0) != 0x80) #define UTF8_POINT(c) (((c) & 0xc0) != 0x80)
#undef MIN
#define MIN(x,y) ((x) < (y) ? (x) : (y))
#undef MAX
#define MAX(x,y) ((x) > (y) ? (x) : (y))
#undef LIMIT
#define LIMIT(x, a, b) (x) = (x) < (a) ? (a) : (x) > (b) ? (b) : (x)
#define LEN(x) (sizeof (x) / sizeof *(x)) #define LEN(x) (sizeof (x) / sizeof *(x))
/* eprintf.c */ /* eprintf.c */