/* $NetBSD: overlay_vfsops.c,v 1.29 2005/02/26 22:59:00 perry Exp $ */ /* * Copyright (c) 1999, 2000 National Aeronautics & Space Administration * All rights reserved. * * This software was written by William Studenmund of the * Numerical Aerospace Simulation Facility, NASA Ames Research Center. * * 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 National Aeronautics & Space Administration * 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 NATIONAL AERONAUTICS & SPACE ADMINISTRATION * ``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 ADMINISTRATION OR CONTRIB- * UTORS 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. */ /* * Copyright (c) 1992, 1993, 1995 * The Regents of the University of California. All rights reserved. * * This code is derived from software donated to Berkeley by * Jan-Simon Pendry. * * 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. * * from: Id: lofs_vfsops.c,v 1.9 1992/05/30 10:26:24 jsp Exp * from: @(#)lofs_vfsops.c 1.2 (Berkeley) 6/18/92 * @(#)null_vfsops.c 8.7 (Berkeley) 5/14/95 */ /* * Overlay Layer * (See overlay_vnops.c for a description of what this does.) */ #include __KERNEL_RCSID(0, "$NetBSD: overlay_vfsops.c,v 1.29 2005/02/26 22:59:00 perry Exp $"); #include #include #include #include #include #include #include #include #include #include #include int ov_mount __P((struct mount *, const char *, void *, struct nameidata *, struct proc *)); int ov_unmount __P((struct mount *, int, struct proc *)); #define NOVERLAYNODECACHE 16 /* * Mount overlay layer */ int ov_mount(mp, path, data, ndp, p) struct mount *mp; const char *path; void *data; struct nameidata *ndp; struct proc *p; { int error = 0; struct overlay_args args; struct vnode *lowerrootvp, *vp; struct overlay_mount *nmp; struct layer_mount *lmp; #ifdef OVERLAYFS_DIAGNOSTIC printf("ov_mount(mp = %p)\n", mp); #endif if (mp->mnt_flag & MNT_GETARGS) { lmp = MOUNTTOLAYERMOUNT(mp); if (lmp == NULL) return EIO; args.la.target = NULL; vfs_showexport(mp, &args.la.export, &lmp->layerm_export); return copyout(&args, data, sizeof(args)); } /* * Get argument */ error = copyin(data, &args, sizeof(struct overlay_args)); if (error) return (error); /* * Update only does export updating. */ if (mp->mnt_flag & MNT_UPDATE) { lmp = MOUNTTOLAYERMOUNT(mp); if (args.ova_target == 0) return (vfs_export(mp, &lmp->layerm_export, &args.la.export)); else return (EOPNOTSUPP); } /* * Find lower node */ lowerrootvp = mp->mnt_vnodecovered; if ((error = vget(lowerrootvp, LK_EXCLUSIVE | LK_RETRY))) return (error); /* * First cut at fixing up upper mount point */ nmp = (struct overlay_mount *) malloc(sizeof(struct overlay_mount), M_UFSMNT, M_WAITOK); /* XXX */ memset(nmp, 0, sizeof(struct overlay_mount)); mp->mnt_data = nmp; mp->mnt_leaf = lowerrootvp->v_mount->mnt_leaf; nmp->ovm_vfs = lowerrootvp->v_mount; if (nmp->ovm_vfs->mnt_flag & MNT_LOCAL) mp->mnt_flag |= MNT_LOCAL; /* * Make sure that the mount point is sufficiently initialized * that the node create call will work. */ vfs_getnewfsid(mp); nmp->ovm_size = sizeof (struct overlay_node); nmp->ovm_tag = VT_OVERLAY; nmp->ovm_bypass = layer_bypass; nmp->ovm_alloc = layer_node_alloc; /* the default alloc is fine */ nmp->ovm_vnodeop_p = overlay_vnodeop_p; simple_lock_init(&nmp->ovm_hashlock); nmp->ovm_node_hashtbl = hashinit(NOVERLAYNODECACHE, HASH_LIST, M_CACHE, M_WAITOK, &nmp->ovm_node_hash); /* * Fix up overlay node for root vnode */ error = layer_node_create(mp, lowerrootvp, &vp); /* * Make sure the fixup worked */ if (error) { vput(lowerrootvp); free(nmp, M_UFSMNT); /* XXX */ return (error); } /* * Unlock the node */ VOP_UNLOCK(vp, 0); /* * Keep a held reference to the root vnode. * It is vrele'd in ov_unmount. */ vp->v_flag |= VROOT; nmp->ovm_rootvp = vp; error = set_statvfs_info(path, UIO_USERSPACE, args.la.target, UIO_USERSPACE, mp, p); #ifdef OVERLAYFS_DIAGNOSTIC printf("ov_mount: lower %s, alias at %s\n", mp->mnt_stat.f_mntfromname, mp->mnt_stat.f_mntonname); #endif return error; } /* * Free reference to overlay layer */ int ov_unmount(mp, mntflags, p) struct mount *mp; int mntflags; struct proc *p; { struct vnode *overlay_rootvp = MOUNTTOOVERLAYMOUNT(mp)->ovm_rootvp; int error; int flags = 0; #ifdef OVERLAYFS_DIAGNOSTIC printf("ov_unmount(mp = %p)\n", mp); #endif if (mntflags & MNT_FORCE) flags |= FORCECLOSE; /* * Clear out buffer cache. I don't think we * ever get anything cached at this level at the * moment, but who knows... */ #if 0 mntflushbuf(mp, 0); if (mntinvalbuf(mp, 1)) return (EBUSY); #endif if (overlay_rootvp->v_usecount > 1) return (EBUSY); if ((error = vflush(mp, overlay_rootvp, flags)) != 0) return (error); #ifdef OVERLAYFS_DIAGNOSTIC vprint("alias root of lower", overlay_rootvp); #endif /* * Release reference on underlying root vnode */ vrele(overlay_rootvp); /* * And blow it away for future re-use */ vgone(overlay_rootvp); /* * Finally, throw away the overlay_mount structure */ free(mp->mnt_data, M_UFSMNT); /* XXX */ mp->mnt_data = 0; return 0; } SYSCTL_SETUP(sysctl_vfs_overlay_setup, "sysctl vfs.overlay subtree setup") { sysctl_createv(clog, 0, NULL, NULL, CTLFLAG_PERMANENT, CTLTYPE_NODE, "vfs", NULL, NULL, 0, NULL, 0, CTL_VFS, CTL_EOL); sysctl_createv(clog, 0, NULL, NULL, CTLFLAG_PERMANENT, CTLTYPE_NODE, "overlay", SYSCTL_DESCR("Overlay file system"), NULL, 0, NULL, 0, CTL_VFS, CTL_CREATE, CTL_EOL); } extern const struct vnodeopv_desc overlay_vnodeop_opv_desc; const struct vnodeopv_desc * const ov_vnodeopv_descs[] = { &overlay_vnodeop_opv_desc, NULL, }; struct vfsops overlay_vfsops = { MOUNT_OVERLAY, ov_mount, layerfs_start, ov_unmount, layerfs_root, layerfs_quotactl, layerfs_statvfs, layerfs_sync, layerfs_vget, layerfs_fhtovp, layerfs_vptofh, layerfs_init, NULL, layerfs_done, NULL, NULL, /* vfs_mountroot */ layerfs_checkexp, layerfs_snapshot, vfs_stdextattrctl, ov_vnodeopv_descs, };