/* $NetBSD: null_vfsops.c,v 1.77 2008/06/24 11:25:05 ad Exp $ */ /* * Copyright (c) 1999 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 */ /* * Null Layer * (See null_vnops.c for a description of what this does.) */ #include __KERNEL_RCSID(0, "$NetBSD: null_vfsops.c,v 1.77 2008/06/24 11:25:05 ad Exp $"); #include #include #include #include #include #include #include #include #include #include #include #include MODULE(MODULE_CLASS_VFS, nullfs, NULL); VFS_PROTOS(nullfs); static struct sysctllog *nullfs_sysctl_log; /* * Mount null layer */ int nullfs_mount(mp, path, data, data_len) struct mount *mp; const char *path; void *data; size_t *data_len; { struct lwp *l = curlwp; struct nameidata nd; struct null_args *args = data; struct vnode *lowerrootvp, *vp; struct null_mount *nmp; struct layer_mount *lmp; int error = 0; #ifdef NULLFS_DIAGNOSTIC printf("nullfs_mount(mp = %p)\n", mp); #endif if (*data_len < sizeof *args) return EINVAL; if (mp->mnt_flag & MNT_GETARGS) { lmp = MOUNTTOLAYERMOUNT(mp); if (lmp == NULL) return EIO; args->la.target = NULL; *data_len = sizeof *args; return 0; } /* * Update is not supported */ if (mp->mnt_flag & MNT_UPDATE) return EOPNOTSUPP; /* * Find lower node */ NDINIT(&nd, LOOKUP, FOLLOW|LOCKLEAF, UIO_USERSPACE, args->la.target); if ((error = namei(&nd)) != 0) return (error); /* * Sanity check on lower vnode */ lowerrootvp = nd.ni_vp; /* * First cut at fixing up upper mount point */ nmp = (struct null_mount *) malloc(sizeof(struct null_mount), M_UFSMNT, M_WAITOK); /* XXX */ memset(nmp, 0, sizeof(struct null_mount)); mp->mnt_data = nmp; nmp->nullm_vfs = lowerrootvp->v_mount; if (nmp->nullm_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->nullm_size = sizeof(struct null_node); nmp->nullm_tag = VT_NULL; nmp->nullm_bypass = layer_bypass; nmp->nullm_alloc = layer_node_alloc; /* the default alloc is fine */ nmp->nullm_vnodeop_p = null_vnodeop_p; mutex_init(&nmp->nullm_hashlock, MUTEX_DEFAULT, IPL_NONE); nmp->nullm_node_hashtbl = hashinit(desiredvnodes, HASH_LIST, true, &nmp->nullm_node_hash); /* * Fix up null node for root vnode */ error = layer_node_create(mp, lowerrootvp, &vp); /* * Make sure the fixup worked */ if (error) { vput(lowerrootvp); hashdone(nmp->nullm_node_hashtbl, HASH_LIST, nmp->nullm_node_hash); free(nmp, M_UFSMNT); /* XXX */ return (error); } /* * Keep a held reference to the root vnode. * It is vrele'd in nullfs_unmount. */ vp->v_vflag |= VV_ROOT; nmp->nullm_rootvp = vp; /* We don't need kernel_lock. */ mp->mnt_iflag |= IMNT_MPSAFE; /* * Unlock the node */ VOP_UNLOCK(vp, 0); error = set_statvfs_info(path, UIO_USERSPACE, args->la.target, UIO_USERSPACE, mp->mnt_op->vfs_name, mp, l); #ifdef NULLFS_DIAGNOSTIC printf("nullfs_mount: lower %s, alias at %s\n", mp->mnt_stat.f_mntfromname, mp->mnt_stat.f_mntonname); #endif return error; } /* * Free reference to null layer */ int nullfs_unmount(struct mount *mp, int mntflags) { struct null_mount *nmp = MOUNTTONULLMOUNT(mp); struct vnode *null_rootvp = nmp->nullm_rootvp; int error; int flags = 0; #ifdef NULLFS_DIAGNOSTIC printf("nullfs_unmount(mp = %p)\n", mp); #endif if (mntflags & MNT_FORCE) flags |= FORCECLOSE; if (null_rootvp->v_usecount > 1 && (mntflags & MNT_FORCE) == 0) return (EBUSY); if ((error = vflush(mp, null_rootvp, flags)) != 0) return (error); #ifdef NULLFS_DIAGNOSTIC vprint("alias root of lower", null_rootvp); #endif /* * Blow it away for future re-use */ vgone(null_rootvp); /* * Finally, throw away the null_mount structure */ hashdone(nmp->nullm_node_hashtbl, HASH_LIST, nmp->nullm_node_hash); mutex_destroy(&nmp->nullm_hashlock); free(mp->mnt_data, M_UFSMNT); /* XXX */ mp->mnt_data = NULL; return (0); } extern const struct vnodeopv_desc null_vnodeop_opv_desc; const struct vnodeopv_desc * const nullfs_vnodeopv_descs[] = { &null_vnodeop_opv_desc, NULL, }; struct vfsops nullfs_vfsops = { MOUNT_NULL, sizeof (struct null_args), nullfs_mount, layerfs_start, nullfs_unmount, layerfs_root, layerfs_quotactl, layerfs_statvfs, layerfs_sync, layerfs_vget, layerfs_fhtovp, layerfs_vptofh, layerfs_init, NULL, layerfs_done, NULL, /* vfs_mountroot */ layerfs_snapshot, vfs_stdextattrctl, (void *)eopnotsupp, /* vfs_suspendctl */ layerfs_renamelock_enter, layerfs_renamelock_exit, (void *)eopnotsupp, nullfs_vnodeopv_descs, 0, { NULL, NULL }, }; static int nullfs_modcmd(modcmd_t cmd, void *arg) { int error; switch (cmd) { case MODULE_CMD_INIT: error = vfs_attach(&nullfs_vfsops); if (error != 0) break; sysctl_createv(&nullfs_sysctl_log, 0, NULL, NULL, CTLFLAG_PERMANENT, CTLTYPE_NODE, "vfs", NULL, NULL, 0, NULL, 0, CTL_VFS, CTL_EOL); sysctl_createv(&nullfs_sysctl_log, 0, NULL, NULL, CTLFLAG_PERMANENT, CTLTYPE_NODE, "null", SYSCTL_DESCR("Loopback file system"), NULL, 0, NULL, 0, CTL_VFS, 9, CTL_EOL); /* * XXX the "9" above could be dynamic, thereby eliminating * one more instance of the "number to vfs" mapping problem, * but "9" is the order as taken from sys/mount.h */ break; case MODULE_CMD_FINI: error = vfs_detach(&nullfs_vfsops); if (error != 0) break; sysctl_teardown(&nullfs_sysctl_log); break; default: error = ENOTTY; break; } return error; }