mirror of
https://github.com/opnsense/src.git
synced 2026-04-23 07:07:24 -04:00
0dc332bff2
fspacectl(2) is a system call to provide space management support to userspace applications. VOP_DEALLOCATE(9) is a VOP call to perform the deallocation. vn_deallocate(9) is a public KPI for kmods' use. The purpose of proposing a new system call, a KPI and a VOP call is to allow bhyve or other hypervisor monitors to emulate the behavior of SCSI UNMAP/NVMe DEALLOCATE on a plain file. fspacectl(2) comprises of cmd and flags parameters to specify the space management operation to be performed. Currently cmd has to be SPACECTL_DEALLOC, and flags has to be 0. fo_fspacectl is added to fileops. VOP_DEALLOCATE(9) is added as a new VOP call. A trivial implementation of VOP_DEALLOCATE(9) is provided. Sponsored by: The FreeBSD Foundation Reviewed by: kib Differential Revision: https://reviews.freebsd.org/D28347
189 lines
4.6 KiB
Groff
189 lines
4.6 KiB
Groff
.\"
|
|
.\" SPDX-License-Identifier: BSD-2-Clause-FreeBSD
|
|
.\"
|
|
.\" Copyright (c) 2021 The FreeBSD Foundation
|
|
.\"
|
|
.\" This manual page was written by Ka Ho Ng under sponsorship from
|
|
.\" the FreeBSD Foundation.
|
|
.\"
|
|
.\" 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 August 4, 2021
|
|
.Dt FSPACECTL 2
|
|
.Os
|
|
.Sh NAME
|
|
.Nm fspacectl
|
|
.Nd space management in a file
|
|
.Sh LIBRARY
|
|
.Lb libc
|
|
.Sh SYNOPSIS
|
|
.In fcntl.h
|
|
.Ft int
|
|
.Fo fspacectl
|
|
.Fa "int fd"
|
|
.Fa "int cmd"
|
|
.Fa "const struct spacectl_range *rqsr"
|
|
.Fa "int flags"
|
|
.Fa "struct spacectl_range *rmsr"
|
|
.Fc
|
|
.Sh DESCRIPTION
|
|
.Nm
|
|
is a system call performing space management over a file.
|
|
The
|
|
.Fa fd
|
|
argument specifies the file descriptor to be operated on by the
|
|
.Fa cmd
|
|
argument.
|
|
The
|
|
.Fa rqsr
|
|
argument points to a
|
|
.Fa spacectl_range
|
|
structure that contains the requested operation range.
|
|
The
|
|
.Fa flags
|
|
argument controls the behavior of the operation to take place.
|
|
If the
|
|
.Fa rmsr
|
|
argument is non-NULL, the
|
|
.Fa spacectl_range
|
|
structure it points to is updated to contain the unprocessed operation range
|
|
after the system call returns.
|
|
Both
|
|
.Fa rqsr
|
|
and
|
|
.Fa rmsr
|
|
arguments can point to the same structure.
|
|
.Pp
|
|
The
|
|
.Fa spacectl_range
|
|
structure is defined as:
|
|
.Bd -literal
|
|
struct spacectl_range {
|
|
off_t r_offset;
|
|
off_t r_len;
|
|
};
|
|
.Ed
|
|
.Pp
|
|
The operation specified by the
|
|
.Fa cmd
|
|
argument may be one of:
|
|
.Bl -tag -width SPACECTL_DEALLOC
|
|
.It Dv SPACECTL_DEALLOC
|
|
Zero a region in the file specified by the
|
|
.Fa rqsr
|
|
argument.
|
|
The
|
|
.Va "rqsr->r_offset"
|
|
has to be a value greater than or equal to 0, and the
|
|
.Va "rqsr->r_len"
|
|
has to be a value greater than 0.
|
|
.Pp
|
|
If the file system supports hole-punching,
|
|
file system space deallocation may be performed in the given region.
|
|
.El
|
|
.Pp
|
|
The
|
|
.Fa flags
|
|
argument needs to be the value 0 currently.
|
|
.Sh RETURN VALUES
|
|
Upon successful completion, the value 0 is returned;
|
|
otherwise the value -1 is returned and
|
|
.Va errno
|
|
is set 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 EINTR
|
|
A signal was caught during execution.
|
|
.It Bq Er EINVAL
|
|
The
|
|
.Fa cmd
|
|
argument is not valid.
|
|
.It Bq Er EINVAL
|
|
If the
|
|
.Fa cmd
|
|
argument is
|
|
.Dv SPACECTL_DEALLOC ,
|
|
either the
|
|
.Fa "range->r_offset"
|
|
argument was less than zero, or the
|
|
.Fa "range->r_len"
|
|
argument was less than or equal to zero.
|
|
.It Bq Er EINVAL
|
|
An invalid or unsupported flag is included in
|
|
.Fa flags .
|
|
.It Bq Er EINVAL
|
|
A flag included in
|
|
.Fa flags
|
|
is not supported by the operation specified by the
|
|
.Fa cmd
|
|
argument.
|
|
.It Bq Er EFAULT
|
|
The
|
|
.Fa rqsr
|
|
or a non-NULL
|
|
.Fa rmsr
|
|
argument point outside the process' allocated address space.
|
|
.It Bq Er EIO
|
|
An I/O error occurred while reading from or writing to a file system.
|
|
.It Bq Er EINTEGRITY
|
|
Corrupted data was detected while reading from the file system.
|
|
.It Bq Er ENODEV
|
|
The
|
|
.Fa fd
|
|
argument does not refer to a file that supports
|
|
.Nm .
|
|
.It Bq Er ENOSPC
|
|
There is insufficient free space remaining on the file system storage
|
|
media.
|
|
.It Bq Er ENOTCAPABLE
|
|
The file descriptor
|
|
.Fa fd
|
|
has insufficient rights.
|
|
.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 HISTORY
|
|
The
|
|
.Nm
|
|
system call appeared in
|
|
.Fx 14.0 .
|
|
.Sh AUTHORS
|
|
.Nm
|
|
and this manual page were written by
|
|
.An Ka Ho Ng Aq Mt khng@FreeBSD.org
|
|
under sponsorship from the FreeBSD Foundation.
|