freebsd-skq/share/man/man9/VOP_COPY_FILE_RANGE.9
Benjamin Kaduk 1f0a85545e Fix grammar nit in copy_file_range docs
Bytes are countable, so we have fewer of them, not less of them.
2019-07-25 15:43:15 +00:00

125 lines
3.7 KiB
Groff

.\" SPDX-License-Identifier: BSD-2-Clause
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.\" Copyright (c) 2019 Rick Macklem
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.Dd July 24, 2019
.Dt VOP_COPY_FILE_RANGE 9
.Os
.Sh NAME
.Nm VOP_COPY_FILE_RANGE
.Nd copy a byte range from one regular file to another within a file system
.Sh SYNOPSIS
.In sys/param.h
.In sys/vnode.h
.Ft int
.Fo VOP_COPY_FILE_RANGE
.Fa "struct vnode *invp"
.Fa "off_t *inoff"
.Fa "struct vnode *outvp"
.Fa "off_t *outoff"
.Fa "size_t *len"
.Fa "unsigned int flags"
.Fa "struct ucred *incred"
.Fa "struct ucred *outcred"
.Fa "struct thread *fsize_td"
.Sh DESCRIPTION
This entry point copies a byte range from one regular file to another within a
file system.
.Pp
The arguments are:
.Bl -tag -width ioflag
.It Fa invp
The vnode of the input file.
.It Fa inoff
A pointer to the file offset for the input file.
.It Fa outvp
The vnode of the output file.
.It Fa outoff
A pointer to the file offset for the output file.
.It Fa len
A pointer to the number of bytes to be copied.
.It Fa flags
Flags, should be set to 0 for now.
.It Fa incred
The credentials used to read
.Fa invp .
.It Fa outcred
The credentials used to write
.Fa outvp .
.It Fa fsize_td
The thread pointer to be passed to vn_rlimit_fsize().
This will be
.Dv NULL
for a server thread without limits, such as for the NFS
server or
.Dv curthread
otherwise.
.El
.Pp
On entry and on return, the
.Fa inoff
and
.Fa outoff
arguments point to the locations of the file offsets.
These file offsets should be updated by the number of bytes copied.
The
.Fa len
argument points to the location that stores the number of bytes
to be copied.
It should be reduced by the number of bytes copied, which implies that
the value pointed to by
.Fa len
will normally be zero for a non-error return.
However, a copy of fewer bytes than requested is permitted.
.Sh LOCKS
The vnode are unlocked on entry and must be unlocked on return.
The byte ranges for both
.Fa invp
and
.Fa outvp
should be range locked when this call is done.
.Sh RETURN VALUES
Zero is returned on success, otherwise an error code is returned.
.Sh ERRORS
.Bl -tag -width Er
.It Bq Er EFBIG
If the copy exceeds the process's file size limit or the maximum file size
for the file system
.Fa invp
and
.Fa outvp
reside on.
.It Bq Er EINTR
A signal interrupted the VOP call before it could be completed.
.It Bq Er EIO
An I/O error occurred while reading/writing the files.
.It Bq Er ENOSPC
The file system is full.
.El
.Sh SEE ALSO
.Xr vn_rdwr 9 ,
.Xr vnode 9