freebsd-dev/sys/fs/deadfs/dead_vnops.c
Konstantin Belousov ee965dfa64 vn_open(): If the vnode is reclaimed during open(2), do not return error.
Most future operations on the returned file descriptor will fail
anyway, and application should be ready to handle that failures.  Not
forcing it to understand the transient failure mode on open, which is
implementation-specific, should make us less special without loss of
reporting of errors.

Suggested by: chs
Reviewed by:	chs, mckusick
Tested by:	pho
MFC after:	2 weeks
Sponsored by:	The FreeBSD Foundation
2021-02-12 03:02:20 +02:00

170 lines
4.1 KiB
C

/*-
* SPDX-License-Identifier: BSD-3-Clause
*
* Copyright (c) 1989, 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.
* 3. 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.
*
* @(#)dead_vnops.c 8.1 (Berkeley) 6/10/93
* $FreeBSD$
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/poll.h>
#include <sys/vnode.h>
/*
* Prototypes for dead operations on vnodes.
*/
static vop_lookup_t dead_lookup;
static vop_open_t dead_open;
static vop_close_t dead_close;
static vop_getwritemount_t dead_getwritemount;
static vop_rename_t dead_rename;
static vop_unset_text_t dead_unset_text;
struct vop_vector dead_vnodeops = {
.vop_default = &default_vnodeops,
.vop_access = VOP_EBADF,
.vop_advlock = VOP_EBADF,
.vop_bmap = VOP_EBADF,
.vop_close = dead_close,
.vop_create = VOP_PANIC,
.vop_getattr = VOP_EBADF,
.vop_getwritemount = dead_getwritemount,
.vop_inactive = VOP_NULL,
.vop_ioctl = VOP_EBADF,
.vop_link = VOP_PANIC,
.vop_lookup = dead_lookup,
.vop_mkdir = VOP_PANIC,
.vop_mknod = VOP_PANIC,
.vop_open = dead_open,
.vop_pathconf = VOP_EBADF, /* per pathconf(2) */
.vop_poll = dead_poll,
.vop_read = dead_read,
.vop_readdir = VOP_EBADF,
.vop_readlink = VOP_EBADF,
.vop_reclaim = VOP_NULL,
.vop_remove = VOP_PANIC,
.vop_rename = dead_rename,
.vop_rmdir = VOP_PANIC,
.vop_setattr = VOP_EBADF,
.vop_symlink = VOP_PANIC,
.vop_vptocnp = VOP_EBADF,
.vop_unset_text = dead_unset_text,
.vop_write = dead_write,
.vop_fplookup_vexec = VOP_EOPNOTSUPP,
.vop_fplookup_symlink = VOP_EAGAIN,
};
VFS_VOP_VECTOR_REGISTER(dead_vnodeops);
static int
dead_getwritemount(struct vop_getwritemount_args *ap)
{
*(ap->a_mpp) = NULL;
return (0);
}
/*
* Trivial lookup routine that always fails.
*/
static int
dead_lookup(struct vop_lookup_args *ap)
{
*ap->a_vpp = NULL;
return (ENOTDIR);
}
/*
* Silently succeed open and close.
*/
static int
dead_open(struct vop_open_args *ap)
{
return (0);
}
static int
dead_close(struct vop_close_args *ap)
{
return (0);
}
int
dead_read(struct vop_read_args *ap)
{
/*
* Return EOF for tty devices, EIO for others
*/
if ((ap->a_vp->v_vflag & VV_ISTTY) == 0)
return (EIO);
return (0);
}
int
dead_write(struct vop_write_args *ap)
{
return (EIO);
}
int
dead_poll(struct vop_poll_args *ap)
{
if (ap->a_events & ~POLLSTANDARD)
return (POLLNVAL);
/*
* Let the user find out that the descriptor is gone.
*/
return (POLLHUP | ((POLLIN | POLLRDNORM) & ap->a_events));
}
static int
dead_rename(struct vop_rename_args *ap)
{
vop_rename_fail(ap);
return (EXDEV);
}
static int
dead_unset_text(struct vop_unset_text_args *ap)
{
return (0);
}