null_vfsops.c revision 1.72
1 /* $NetBSD: null_vfsops.c,v 1.72 2008/01/02 11:49:00 ad Exp $ */ 2 3 /* 4 * Copyright (c) 1999 National Aeronautics & Space Administration 5 * All rights reserved. 6 * 7 * This software was written by William Studenmund of the 8 * Numerical Aerospace Simulation Facility, NASA Ames Research Center. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. Neither the name of the National Aeronautics & Space Administration 19 * nor the names of its contributors may be used to endorse or promote 20 * products derived from this software without specific prior written 21 * permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE NATIONAL AERONAUTICS & SPACE ADMINISTRATION 24 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 25 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 26 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE ADMINISTRATION OR CONTRIB- 27 * UTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, 28 * OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 29 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 30 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 31 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 32 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 33 * POSSIBILITY OF SUCH DAMAGE. 34 */ 35 /* 36 * Copyright (c) 1992, 1993, 1995 37 * The Regents of the University of California. All rights reserved. 38 * 39 * This code is derived from software donated to Berkeley by 40 * Jan-Simon Pendry. 41 * 42 * Redistribution and use in source and binary forms, with or without 43 * modification, are permitted provided that the following conditions 44 * are met: 45 * 1. Redistributions of source code must retain the above copyright 46 * notice, this list of conditions and the following disclaimer. 47 * 2. Redistributions in binary form must reproduce the above copyright 48 * notice, this list of conditions and the following disclaimer in the 49 * documentation and/or other materials provided with the distribution. 50 * 3. Neither the name of the University nor the names of its contributors 51 * may be used to endorse or promote products derived from this software 52 * without specific prior written permission. 53 * 54 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 55 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 56 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 57 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 58 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 59 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 60 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 61 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 62 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 63 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 64 * SUCH DAMAGE. 65 * 66 * from: Id: lofs_vfsops.c,v 1.9 1992/05/30 10:26:24 jsp Exp 67 * from: @(#)lofs_vfsops.c 1.2 (Berkeley) 6/18/92 68 * @(#)null_vfsops.c 8.7 (Berkeley) 5/14/95 69 */ 70 71 /* 72 * Null Layer 73 * (See null_vnops.c for a description of what this does.) 74 */ 75 76 #include <sys/cdefs.h> 77 __KERNEL_RCSID(0, "$NetBSD: null_vfsops.c,v 1.72 2008/01/02 11:49:00 ad Exp $"); 78 79 #include <sys/param.h> 80 #include <sys/systm.h> 81 #include <sys/sysctl.h> 82 #include <sys/time.h> 83 #include <sys/proc.h> 84 #include <sys/vnode.h> 85 #include <sys/mount.h> 86 #include <sys/namei.h> 87 #include <sys/malloc.h> 88 89 #include <miscfs/nullfs/null.h> 90 #include <miscfs/genfs/layer_extern.h> 91 92 VFS_PROTOS(nullfs); 93 94 /* 95 * Mount null layer 96 */ 97 int 98 nullfs_mount(mp, path, data, data_len) 99 struct mount *mp; 100 const char *path; 101 void *data; 102 size_t *data_len; 103 { 104 struct lwp *l = curlwp; 105 struct nameidata nd; 106 struct null_args *args = data; 107 struct vnode *lowerrootvp, *vp; 108 struct null_mount *nmp; 109 struct layer_mount *lmp; 110 int error = 0; 111 112 #ifdef NULLFS_DIAGNOSTIC 113 printf("nullfs_mount(mp = %p)\n", mp); 114 #endif 115 116 if (*data_len < sizeof *args) 117 return EINVAL; 118 119 if (mp->mnt_flag & MNT_GETARGS) { 120 lmp = MOUNTTOLAYERMOUNT(mp); 121 if (lmp == NULL) 122 return EIO; 123 args->la.target = NULL; 124 *data_len = sizeof *args; 125 return 0; 126 } 127 128 /* 129 * Update is not supported 130 */ 131 if (mp->mnt_flag & MNT_UPDATE) 132 return EOPNOTSUPP; 133 134 /* 135 * Find lower node 136 */ 137 NDINIT(&nd, LOOKUP, FOLLOW|LOCKLEAF, UIO_USERSPACE, args->la.target); 138 if ((error = namei(&nd)) != 0) 139 return (error); 140 141 /* 142 * Sanity check on lower vnode 143 */ 144 lowerrootvp = nd.ni_vp; 145 146 /* 147 * First cut at fixing up upper mount point 148 */ 149 nmp = (struct null_mount *) malloc(sizeof(struct null_mount), 150 M_UFSMNT, M_WAITOK); /* XXX */ 151 memset(nmp, 0, sizeof(struct null_mount)); 152 153 mp->mnt_data = nmp; 154 nmp->nullm_vfs = lowerrootvp->v_mount; 155 if (nmp->nullm_vfs->mnt_flag & MNT_LOCAL) 156 mp->mnt_flag |= MNT_LOCAL; 157 158 /* 159 * Make sure that the mount point is sufficiently initialized 160 * that the node create call will work. 161 */ 162 vfs_getnewfsid(mp); 163 164 nmp->nullm_size = sizeof(struct null_node); 165 nmp->nullm_tag = VT_NULL; 166 nmp->nullm_bypass = layer_bypass; 167 nmp->nullm_alloc = layer_node_alloc; /* the default alloc is fine */ 168 nmp->nullm_vnodeop_p = null_vnodeop_p; 169 mutex_init(&nmp->nullm_hashlock, MUTEX_DEFAULT, IPL_NONE); 170 nmp->nullm_node_hashtbl = hashinit(desiredvnodes, HASH_LIST, M_CACHE, 171 M_WAITOK, &nmp->nullm_node_hash); 172 173 /* 174 * Fix up null node for root vnode 175 */ 176 error = layer_node_create(mp, lowerrootvp, &vp); 177 /* 178 * Make sure the fixup worked 179 */ 180 if (error) { 181 vput(lowerrootvp); 182 hashdone(nmp->nullm_node_hashtbl, M_CACHE); 183 free(nmp, M_UFSMNT); /* XXX */ 184 return (error); 185 } 186 /* 187 * Keep a held reference to the root vnode. 188 * It is vrele'd in nullfs_unmount. 189 */ 190 vp->v_vflag |= VV_ROOT; 191 nmp->nullm_rootvp = vp; 192 193 /* We don't need kernel_lock. */ 194 mp->mnt_iflag |= IMNT_MPSAFE; 195 196 /* 197 * Unlock the node 198 */ 199 VOP_UNLOCK(vp, 0); 200 201 error = set_statvfs_info(path, UIO_USERSPACE, args->la.target, 202 UIO_USERSPACE, mp->mnt_op->vfs_name, mp, l); 203 #ifdef NULLFS_DIAGNOSTIC 204 printf("nullfs_mount: lower %s, alias at %s\n", 205 mp->mnt_stat.f_mntfromname, mp->mnt_stat.f_mntonname); 206 #endif 207 return error; 208 } 209 210 /* 211 * Free reference to null layer 212 */ 213 int 214 nullfs_unmount(struct mount *mp, int mntflags) 215 { 216 struct null_mount *nmp = MOUNTTONULLMOUNT(mp); 217 struct vnode *null_rootvp = nmp->nullm_rootvp; 218 int error; 219 int flags = 0; 220 221 #ifdef NULLFS_DIAGNOSTIC 222 printf("nullfs_unmount(mp = %p)\n", mp); 223 #endif 224 225 if (mntflags & MNT_FORCE) 226 flags |= FORCECLOSE; 227 228 if (null_rootvp->v_usecount > 1 && (mntflags & MNT_FORCE) == 0) 229 return (EBUSY); 230 if ((error = vflush(mp, null_rootvp, flags)) != 0) 231 return (error); 232 233 #ifdef NULLFS_DIAGNOSTIC 234 vprint("alias root of lower", null_rootvp); 235 #endif 236 /* 237 * Blow it away for future re-use 238 */ 239 vgone(null_rootvp); 240 241 /* 242 * Finally, throw away the null_mount structure 243 */ 244 hashdone(nmp->nullm_node_hashtbl, M_CACHE); 245 mutex_destroy(&nmp->nullm_hashlock); 246 free(mp->mnt_data, M_UFSMNT); /* XXX */ 247 mp->mnt_data = NULL; 248 return (0); 249 } 250 251 SYSCTL_SETUP(sysctl_vfs_null_setup, "sysctl vfs.null subtree setup") 252 { 253 254 sysctl_createv(clog, 0, NULL, NULL, 255 CTLFLAG_PERMANENT, 256 CTLTYPE_NODE, "vfs", NULL, 257 NULL, 0, NULL, 0, 258 CTL_VFS, CTL_EOL); 259 sysctl_createv(clog, 0, NULL, NULL, 260 CTLFLAG_PERMANENT, 261 CTLTYPE_NODE, "null", 262 SYSCTL_DESCR("Loopback file system"), 263 NULL, 0, NULL, 0, 264 CTL_VFS, 9, CTL_EOL); 265 /* 266 * XXX the "9" above could be dynamic, thereby eliminating one 267 * more instance of the "number to vfs" mapping problem, but 268 * "9" is the order as taken from sys/mount.h 269 */ 270 } 271 272 extern const struct vnodeopv_desc null_vnodeop_opv_desc; 273 274 const struct vnodeopv_desc * const nullfs_vnodeopv_descs[] = { 275 &null_vnodeop_opv_desc, 276 NULL, 277 }; 278 279 struct vfsops nullfs_vfsops = { 280 MOUNT_NULL, 281 sizeof (struct null_args), 282 nullfs_mount, 283 layerfs_start, 284 nullfs_unmount, 285 layerfs_root, 286 layerfs_quotactl, 287 layerfs_statvfs, 288 layerfs_sync, 289 layerfs_vget, 290 layerfs_fhtovp, 291 layerfs_vptofh, 292 layerfs_init, 293 NULL, 294 layerfs_done, 295 NULL, /* vfs_mountroot */ 296 layerfs_snapshot, 297 vfs_stdextattrctl, 298 (void *)eopnotsupp, /* vfs_suspendctl */ 299 nullfs_vnodeopv_descs, 300 0, 301 { NULL, NULL }, 302 }; 303 VFS_ATTACH(nullfs_vfsops); 304
Indexes created Thu Sep 25 15:09:46 GMT 2025