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VOP_ALLOCATE.9
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VOP_ALLOCATE.9
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.\" -*- nroff -*-
.\"
.\" Copyright (c) 2013 Hudson River Trading LLC
.\" Written by: John H. Baldwin <[email protected]>
.\" 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.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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.
.\"
.Dd November 8, 2021
.Dt VOP_ALLOCATE 9
.Os
.Sh NAME
.Nm VOP_ALLOCATE
.Nd allocate storage for a file
.Sh SYNOPSIS
.In sys/param.h
.In sys/vnode.h
.Ft int
.Fo VOP_ALLOCATE
.Fa "struct vnode *vp"
.Fa "off_t *offset"
.Fa "off_t *len"
.Fa "int ioflag"
.Fa "struct ucred *cred"
.Fc
.Sh DESCRIPTION
This call allocates storage for a range of offsets in a file.
It is used to implement the
.Xr posix_fallocate
system call.
.Pp
Its arguments are:
.Bl -tag -width offset
.It Fa vp
The vnode of the file.
.It Fa offset
The start of the range to allocate storage for in the file.
.It Fa len
The length of the range to allocate storage for in the file.
.It Fa ioflag
Directives and hints to be given to the file system.
.It Fa cred
The credentials of the caller.
.El
.Pp
The
.Fa offset
and
.Fa len
arguments are updated to reflect the portion of the range that
still needs to be allocated on return.
A partial allocation is considered a successful operation.
The file's contents are not changed.
.Sh LOCKS
The file should be exclusively locked on entry and will still be locked on exit.
.Sh RETURN VALUES
Zero is returned if the call is successful, otherwise an appropriate
error code is returned.
.Sh ERRORS
.Bl -tag -width Er
.It Bq Er EFBIG
An attempt was made to write a file that exceeds the process's file size
limit or the maximum file size.
.It Bq Er ENOSPC
The file system is full.
.It Bq Er EPERM
An append-only flag is set on the file, but the caller is attempting to
write before the current end of file.
.El
.Sh SEE ALSO
.Xr vnode 9 ,
.Xr VOP_READ 9 ,
.Xr VOP_WRITE 9