fallocate: new command

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@redhat.com>
Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: Karel Zak <kzak@redhat.com>

1 files changed, 51 insertions, 0 deletions

diff --git a/sys-utils/fallocate.1 b/sys-utils/fallocate.1
new file mode 100644
index 000000000..00e973ceb
--- /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@redhat.com>
+Karel Zak <kzak@redhat.com>
+.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/.
+