378 lines
10 KiB
C
378 lines
10 KiB
C
/* $NetBSD: layer_vfsops.c,v 1.54 2020/02/23 15:46:41 ad Exp $ */
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/*
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* Copyright (c) 1999 National Aeronautics & Space Administration
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* All rights reserved.
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*
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* This software was written by William Studenmund of the
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* Numerical Aerospace Simulation Facility, NASA Ames Research Center.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the National Aeronautics & Space Administration
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* nor the names of its contributors may be used to endorse or promote
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* products derived from this software without specific prior written
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* permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE NATIONAL AERONAUTICS & SPACE ADMINISTRATION
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* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
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* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE ADMINISTRATION OR CONTRIB-
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* UTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
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* OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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/*
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* Copyright (c) 1992, 1993, 1995
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* The Regents of the University of California. All rights reserved.
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*
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* This code is derived from software donated to Berkeley by
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* Jan-Simon Pendry.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* from: Id: lofs_vfsops.c,v 1.9 1992/05/30 10:26:24 jsp Exp
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* from: @(#)lofs_vfsops.c 1.2 (Berkeley) 6/18/92
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* @(#)null_vfsops.c 8.7 (Berkeley) 5/14/95
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*/
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/*
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* Generic layer VFS operations.
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*/
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#include <sys/cdefs.h>
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__KERNEL_RCSID(0, "$NetBSD: layer_vfsops.c,v 1.54 2020/02/23 15:46:41 ad Exp $");
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#include <sys/param.h>
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#include <sys/sysctl.h>
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#include <sys/systm.h>
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#include <sys/vnode.h>
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#include <sys/mount.h>
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#include <sys/namei.h>
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#include <sys/kauth.h>
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#include <sys/module.h>
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#include <miscfs/specfs/specdev.h>
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#include <miscfs/genfs/genfs.h>
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#include <miscfs/genfs/layer.h>
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#include <miscfs/genfs/layer_extern.h>
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SYSCTL_SETUP_PROTO(sysctl_vfs_layerfs_setup);
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MODULE(MODULE_CLASS_MISC, layerfs, NULL);
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static int
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layerfs_modcmd(modcmd_t cmd, void *arg)
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{
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switch (cmd) {
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case MODULE_CMD_INIT:
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return 0;
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case MODULE_CMD_FINI:
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return 0;
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default:
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return ENOTTY;
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}
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return 0;
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}
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/*
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* VFS start. Nothing needed here - the start routine on the underlying
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* filesystem will have been called when that filesystem was mounted.
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*/
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int
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layerfs_start(struct mount *mp, int flags)
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{
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#ifdef notyet
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return VFS_START(mp->mnt_lower, flags);
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#else
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return 0;
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#endif
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}
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int
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layerfs_root(struct mount *mp, int lktype, struct vnode **vpp)
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{
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struct vnode *vp;
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vp = MOUNTTOLAYERMOUNT(mp)->layerm_rootvp;
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if (vp == NULL) {
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*vpp = NULL;
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return EINVAL;
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}
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/*
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* Return root vnode with locked and with a reference held.
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*/
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vref(vp);
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vn_lock(vp, lktype | LK_RETRY);
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*vpp = vp;
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return 0;
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}
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int
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layerfs_quotactl(struct mount *mp, struct quotactl_args *args)
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{
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return VFS_QUOTACTL(mp->mnt_lower, args);
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}
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int
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layerfs_statvfs(struct mount *mp, struct statvfs *sbp)
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{
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struct statvfs *sbuf;
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int error;
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sbuf = kmem_zalloc(sizeof(*sbuf), KM_SLEEP);
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error = VFS_STATVFS(mp->mnt_lower, sbuf);
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if (error) {
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goto done;
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}
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/* Copy across the relevant data and fake the rest. */
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sbp->f_flag = sbuf->f_flag;
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sbp->f_bsize = sbuf->f_bsize;
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sbp->f_frsize = sbuf->f_frsize;
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sbp->f_iosize = sbuf->f_iosize;
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sbp->f_blocks = sbuf->f_blocks;
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sbp->f_bfree = sbuf->f_bfree;
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sbp->f_bavail = sbuf->f_bavail;
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sbp->f_bresvd = sbuf->f_bresvd;
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sbp->f_files = sbuf->f_files;
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sbp->f_ffree = sbuf->f_ffree;
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sbp->f_favail = sbuf->f_favail;
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sbp->f_fresvd = sbuf->f_fresvd;
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sbp->f_namemax = sbuf->f_namemax;
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copy_statvfs_info(sbp, mp);
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done:
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kmem_free(sbuf, sizeof(*sbuf));
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return error;
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}
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int
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layerfs_sync(struct mount *mp, int waitfor,
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kauth_cred_t cred)
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{
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/*
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* XXX - Assumes no data cached at layer.
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*/
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return 0;
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}
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int
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layerfs_loadvnode(struct mount *mp, struct vnode *vp,
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const void *key, size_t key_len, const void **new_key)
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{
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struct layer_mount *lmp = MOUNTTOLAYERMOUNT(mp);
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struct vnode *lowervp;
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struct layer_node *xp;
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KASSERT(key_len == sizeof(struct vnode *));
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memcpy(&lowervp, key, key_len);
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xp = kmem_alloc(lmp->layerm_size, KM_SLEEP);
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/* Share the interlock and vmobjlock with the lower node. */
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vshareilock(vp, lowervp);
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rw_obj_hold(lowervp->v_uobj.vmobjlock);
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uvm_obj_setlock(&vp->v_uobj, lowervp->v_uobj.vmobjlock);
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vp->v_tag = lmp->layerm_tag;
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vp->v_type = lowervp->v_type;
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vp->v_op = lmp->layerm_vnodeop_p;
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if (vp->v_type == VBLK || vp->v_type == VCHR)
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spec_node_init(vp, lowervp->v_rdev);
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vp->v_data = xp;
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xp->layer_vnode = vp;
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xp->layer_lowervp = lowervp;
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xp->layer_flags = 0;
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uvm_vnp_setsize(vp, 0);
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/* Add a reference to the lower node. */
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vref(lowervp);
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*new_key = &xp->layer_lowervp;
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return 0;
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}
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int
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layerfs_vget(struct mount *mp, ino_t ino, int lktype, struct vnode **vpp)
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{
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struct vnode *vp;
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int error;
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error = VFS_VGET(mp->mnt_lower, ino, lktype, &vp);
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if (error) {
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*vpp = NULL;
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return error;
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}
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VOP_UNLOCK(vp);
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error = layer_node_create(mp, vp, vpp);
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if (error) {
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vrele(vp);
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*vpp = NULL;
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return error;
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}
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error = vn_lock(*vpp, lktype);
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if (error) {
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vrele(*vpp);
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*vpp = NULL;
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return error;
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}
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return 0;
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}
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int
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layerfs_fhtovp(struct mount *mp, struct fid *fidp, int lktype,
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struct vnode **vpp)
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{
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struct vnode *vp;
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int error;
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error = VFS_FHTOVP(mp->mnt_lower, fidp, lktype, &vp);
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if (error) {
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*vpp = NULL;
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return error;
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}
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VOP_UNLOCK(vp);
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error = layer_node_create(mp, vp, vpp);
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if (error) {
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vput(vp);
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*vpp = NULL;
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return (error);
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}
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error = vn_lock(*vpp, lktype);
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if (error) {
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vrele(*vpp);
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*vpp = NULL;
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return error;
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}
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return 0;
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}
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int
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layerfs_vptofh(struct vnode *vp, struct fid *fhp, size_t *fh_size)
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{
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return VFS_VPTOFH(LAYERVPTOLOWERVP(vp), fhp, fh_size);
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}
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/*
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* layerfs_snapshot - handle a snapshot through a layered file system
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*
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* At present, we do NOT support snapshotting through a layered file
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* system as the ffs implementation changes v_vnlock of the snapshot
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* vnodes to point to one common lock. As there is no way for us to
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* absolutely pass this change up the stack, a layered file system
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* would end up referencing the wrong lock.
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*
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* This routine serves as a central resource for this behavior; all
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* layered file systems don't need to worry about the above. Also, if
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* things get fixed, all layers get the benefit.
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*/
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int
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layerfs_snapshot(struct mount *mp, struct vnode *vp,
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struct timespec *ts)
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{
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return EOPNOTSUPP;
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}
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/*
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* layerfs_suspendctl - suspend a layered file system
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*
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* Here we should suspend the lower file system(s) too. At present
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* this will deadlock as we don't know which to suspend first.
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*
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* This routine serves as a central resource for this behavior; all
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* layered file systems don't need to worry about the above. Also, if
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* things get fixed, all layers get the benefit.
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*/
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int
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layerfs_suspendctl(struct mount *mp, int cmd)
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{
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return genfs_suspendctl(mp, cmd);
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}
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SYSCTL_SETUP(sysctl_vfs_layerfs_setup, "sysctl vfs.layerfs subtree setup")
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{
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const struct sysctlnode *layerfs_node = NULL;
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sysctl_createv(clog, 0, NULL, &layerfs_node,
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#ifdef _MODULE
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0,
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#else
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CTLFLAG_PERMANENT,
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#endif
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CTLTYPE_NODE, "layerfs",
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SYSCTL_DESCR("Generic layered file system"),
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NULL, 0, NULL, 0,
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CTL_VFS, CTL_CREATE, CTL_EOL);
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#ifdef LAYERFS_DIAGNOSTIC
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sysctl_createv(clog, 0, &layerfs_node, NULL,
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#ifndef _MODULE
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CTLFLAG_PERMANENT |
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#endif
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CTLFLAG_READWRITE,
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CTLTYPE_INT,
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"debug",
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SYSCTL_DESCR("Verbose debugging messages"),
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NULL, 0, &layerfs_debug, 0,
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CTL_CREATE, CTL_EOL);
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#endif
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/*
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* other subtrees should really be aliases to this, but since
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* they can't tell if layerfs has been instantiated yet, they
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* can't do that...not easily. not yet. :-)
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*/
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}
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int
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layerfs_renamelock_enter(struct mount *mp)
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{
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return VFS_RENAMELOCK_ENTER(mp->mnt_lower);
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}
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void
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layerfs_renamelock_exit(struct mount *mp)
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{
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VFS_RENAMELOCK_EXIT(mp->mnt_lower);
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}
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