Add the posix_fallocate(2) syscall. The default implementation in

vop_stdallocate() is filesystem agnostic and will run as slow as a
read/write loop in userspace; however, it serves to correctly
implement the functionality for filesystems that do not implement a
VOP_ALLOCATE.

Note that __FreeBSD_version was already bumped today to 900036 for any
ports which would like to use this function.

Also reserve space in the syscall table for posix_fadvise(2).

Reviewed by:	-arch (previous version)

3 files changed, 148 insertions, 1 deletions

diff --git a/lib/libc/sys/Makefile.inc b/lib/libc/sys/Makefile.inc
index 152a14a..008180a 100644
--- a/lib/libc/sys/Makefile.inc
+++ b/lib/libc/sys/Makefile.inc
@@ -96,7 +96,7 @@ MAN+=	abort2.2 accept.2 access.2 acct.2 adjtime.2 \
 	mq_setattr.2 \
 	msgctl.2 msgget.2 msgrcv.2 msgsnd.2 \
 	msync.2 munmap.2 nanosleep.2 nfssvc.2 ntp_adjtime.2 open.2 \
-	pathconf.2 pipe.2 poll.2 posix_openpt.2 profil.2 \
+	pathconf.2 pipe.2 poll.2 posix_fallocate.2 posix_openpt.2 profil.2 \
 	pselect.2 ptrace.2 quotactl.2 \
 	read.2 readlink.2 reboot.2 recv.2 rename.2 revoke.2 rfork.2 rmdir.2 \
 	rtprio.2
diff --git a/lib/libc/sys/Symbol.map b/lib/libc/sys/Symbol.map
index 4cb18c6..cd31f24 100644
--- a/lib/libc/sys/Symbol.map
+++ b/lib/libc/sys/Symbol.map
@@ -364,6 +364,7 @@ FBSD_1.2 {
 	cap_enter;
 	cap_getmode;
 	getloginclass;
+	posix_fallocate;
 	rctl_get_racct;
 	rctl_get_rules;
 	rctl_get_limits;
diff --git a/lib/libc/sys/posix_fallocate.2 b/lib/libc/sys/posix_fallocate.2
new file mode 100644
index 0000000..f7cbd49
--- /dev/null
+++ b/lib/libc/sys/posix_fallocate.2
@@ -0,0 +1,146 @@
+.\" Copyright (c) 1980, 1991, 1993
+.\"	The Regents of the University of California.  All rights reserved.
+.\"
+.\" Redistribution and use in source and binary forms, with or without
+.\" modification, are permitted provided that the following conditions
+.\" are met:
+.\" 1. Redistributions of source code must retain the above copyright
+.\"    notice, this list of conditions and the following disclaimer.
+.\" 2. Redistributions in binary form must reproduce the above copyright
+.\"    notice, this list of conditions and the following disclaimer in the
+.\"    documentation and/or other materials provided with the distribution.
+.\" 4. Neither the name of the University nor the names of its contributors
+.\"    may be used to endorse or promote products derived from this software
+.\"    without specific prior written permission.
+.\"
+.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+.\" SUCH DAMAGE.
+.\"
+.\"     @(#)open.2	8.2 (Berkeley) 11/16/93
+.\" $FreeBSD$
+.\"
+.Dd April 13, 2011
+.Dt POSIX_FALLOCATE 2
+.Os
+.Sh NAME
+.Nm posix_fallocate
+.Nd pre-allocate storage for a range in a file
+.Sh LIBRARY
+.Lb libc
+.Sh SYNOPSIS
+.In fcntl.h
+.Ft int
+.Fn posix_fallocate "int fd" "off_t offset" "off_t len"
+.Sh DESCRIPTION
+Required storage for the range
+.Fa offset
+to
+.Fa offset +
+.Fa len
+in the file referenced by
+.Fa fd
+is guarateed to be allocated upon successful return.
+That is, if
+.Fn posix_fallocate
+returns successfully, subsequent writes to the specified file data
+will not fail due to lack of free space on the file system storage
+media.
+Any existing file data in the specified range is unmodified.
+If
+.Fa offset +
+.Fa len
+is beyond the current file size, then
+.Fn posix_fallocate
+will adjust the file size to
+.Fa offset +
+.Fa len .
+Otherwise, the file size will not be changed.
+.Pp
+Space allocated by
+.Fn posix_fallocate
+will be freed by a successful call to
+.Xr creat 2
+or
+.Xr open 2
+that truncates the size of the file.
+Space allocated via
+.Fn posix_fallocate
+may be freed by a successful call to
+.Xr ftruncate 2
+that reduces the file size to a size smaller than
+.Fa offset +
+.Fa len .
+.Pp
+.Sh RETURN VALUES
+If successful,
+.Fn posix_fallocate
+returns zero.
+It returns -1 on failure, and sets
+.Va errno
+to indicate the error.
+.Sh ERRORS
+Possible failure conditions:
+.Bl -tag -width Er
+.It Bq Er EBADF
+The
+.Fa fd
+argument is not a valid file descriptor.
+.It Bq Er EBADF
+The
+.Fa fd
+argument references a file that was opened without write permission.
+.It Bq Er EFBIG
+The value of
+.Fa offset +
+.Fa len
+is greater than the maximum file size.
+.It Bq Er EINTR
+A signal was caught during execution.
+.It Bq Er EINVAL
+The
+.Fa len
+argument was zero or the
+.Fa offset
+argument was less than zero.
+.It Bq Er EIO
+An I/O error occurred while reading from or writing to a file system.
+.It Bq Er ENODEV
+The
+.Fa fd
+argument does not refer to a regular file.
+.It Bq Er ENOSPC
+There is insufficient free space remaining on the file system storage
+media.
+.It Bq Er ESPIPE
+The
+.Fa fd
+argument is associated with a pipe or FIFO.
+.El
+.Sh SEE ALSO
+.Xr creat 2 ,
+.Xr ftruncate 2 ,
+.Xr open 2 ,
+.Xr unlink 2
+.Sh STANDARDS
+The
+.Fn posix_fallocate
+system call conforms to
+.St -p1003.1-2004 .
+.Sh HISTORY
+The
+.Fn posix_fallocate
+function appeared in
+.Fx 9.0 .
+.Sh AUTHORS
+.Fn posix_fallocate
+and this manual page were initially written by
+.An Matthew Fleming Aq mdf@FreeBSD.org .