null_vfsops.c revision 1.48
1 /* $NetBSD: null_vfsops.c,v 1.48 2004/04/29 16:10:55 jrf 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 1.48 2004/04/29 16:10:55 jrf 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 int nullfs_mount __P((struct mount *, const char *, void *, 93 struct nameidata *, struct proc *)); 94 int nullfs_unmount __P((struct mount *, int, struct proc *)); 95 96 /* 97 * Mount null layer 98 */ 99 int 100 nullfs_mount(mp, path, data, ndp, p) 101 struct mount *mp; 102 const char *path; 103 void *data; 104 struct nameidata *ndp; 105 struct proc *p; 106 { 107 struct null_args args; 108 struct vnode *lowerrootvp, *vp; 109 struct null_mount *nmp; 110 struct layer_mount *lmp; 111 int error = 0; 112 113 #ifdef NULLFS_DIAGNOSTIC 114 printf("nullfs_mount(mp = %p)\n", mp); 115 #endif 116 117 if (mp->mnt_flag & MNT_GETARGS) { 118 lmp = MOUNTTOLAYERMOUNT(mp); 119 if (lmp == NULL) 120 return EIO; 121 args.la.target = NULL; 122 vfs_showexport(mp, &args.la.export, &lmp->layerm_export); 123 return copyout(&args, data, sizeof(args)); 124 } 125 /* 126 * Get argument 127 */ 128 error = copyin(data, &args, sizeof(struct null_args)); 129 if (error) 130 return (error); 131 132 /* 133 * Update only does export updating. 134 */ 135 if (mp->mnt_flag & MNT_UPDATE) { 136 lmp = MOUNTTOLAYERMOUNT(mp); 137 if (args.nulla_target == NULL) 138 return (vfs_export(mp, &lmp->layerm_export, 139 &args.la.export)); 140 else 141 return (EOPNOTSUPP); 142 } 143 144 /* 145 * Find lower node 146 */ 147 NDINIT(ndp, LOOKUP, FOLLOW|LOCKLEAF, 148 UIO_USERSPACE, args.la.target, p); 149 if ((error = namei(ndp)) != 0) 150 return (error); 151 152 /* 153 * Sanity check on lower vnode 154 */ 155 lowerrootvp = ndp->ni_vp; 156 157 /* 158 * First cut at fixing up upper mount point 159 */ 160 nmp = (struct null_mount *) malloc(sizeof(struct null_mount), 161 M_UFSMNT, M_WAITOK); /* XXX */ 162 memset(nmp, 0, sizeof(struct null_mount)); 163 164 mp->mnt_data = nmp; 165 nmp->nullm_vfs = lowerrootvp->v_mount; 166 if (nmp->nullm_vfs->mnt_flag & MNT_LOCAL) 167 mp->mnt_flag |= MNT_LOCAL; 168 169 /* 170 * Make sure that the mount point is sufficiently initialized 171 * that the node create call will work. 172 */ 173 vfs_getnewfsid(mp); 174 175 nmp->nullm_size = sizeof(struct null_node); 176 nmp->nullm_tag = VT_NULL; 177 nmp->nullm_bypass = layer_bypass; 178 nmp->nullm_alloc = layer_node_alloc; /* the default alloc is fine */ 179 nmp->nullm_vnodeop_p = null_vnodeop_p; 180 simple_lock_init(&nmp->nullm_hashlock); 181 nmp->nullm_node_hashtbl = hashinit(desiredvnodes, HASH_LIST, M_CACHE, 182 M_WAITOK, &nmp->nullm_node_hash); 183 184 /* 185 * Fix up null node for root vnode 186 */ 187 error = layer_node_create(mp, lowerrootvp, &vp); 188 /* 189 * Make sure the fixup worked 190 */ 191 if (error) { 192 vput(lowerrootvp); 193 hashdone(nmp->nullm_node_hashtbl, M_CACHE); 194 free(nmp, M_UFSMNT); /* XXX */ 195 return (error); 196 } 197 /* 198 * Unlock the node 199 */ 200 VOP_UNLOCK(vp, 0); 201 202 /* 203 * Keep a held reference to the root vnode. 204 * It is vrele'd in nullfs_unmount. 205 */ 206 vp->v_flag |= VROOT; 207 nmp->nullm_rootvp = vp; 208 209 error = set_statvfs_info(path, UIO_USERSPACE, args.la.target, 210 UIO_USERSPACE, mp, p); 211 #ifdef NULLFS_DIAGNOSTIC 212 printf("nullfs_mount: lower %s, alias at %s\n", 213 mp->mnt_stat.f_mntfromname, mp->mnt_stat.f_mntonname); 214 #endif 215 return error; 216 } 217 218 /* 219 * Free reference to null layer 220 */ 221 int 222 nullfs_unmount(mp, mntflags, p) 223 struct mount *mp; 224 int mntflags; 225 struct proc *p; 226 { 227 struct null_mount *nmp = MOUNTTONULLMOUNT(mp); 228 struct vnode *null_rootvp = nmp->nullm_rootvp; 229 int error; 230 int flags = 0; 231 232 #ifdef NULLFS_DIAGNOSTIC 233 printf("nullfs_unmount(mp = %p)\n", mp); 234 #endif 235 236 if (mntflags & MNT_FORCE) 237 flags |= FORCECLOSE; 238 239 /* 240 * Clear out buffer cache. I don't think we 241 * ever get anything cached at this level at the 242 * moment, but who knows... 243 */ 244 #if 0 245 mntflushbuf(mp, 0); 246 if (mntinvalbuf(mp, 1)) 247 return (EBUSY); 248 #endif 249 if (null_rootvp->v_usecount > 1) 250 return (EBUSY); 251 if ((error = vflush(mp, null_rootvp, flags)) != 0) 252 return (error); 253 254 #ifdef NULLFS_DIAGNOSTIC 255 vprint("alias root of lower", null_rootvp); 256 #endif 257 /* 258 * Release reference on underlying root vnode 259 */ 260 vrele(null_rootvp); 261 262 /* 263 * And blow it away for future re-use 264 */ 265 vgone(null_rootvp); 266 267 /* 268 * Finally, throw away the null_mount structure 269 */ 270 hashdone(nmp->nullm_node_hashtbl, M_CACHE); 271 free(mp->mnt_data, M_UFSMNT); /* XXX */ 272 mp->mnt_data = NULL; 273 return (0); 274 } 275 276 SYSCTL_SETUP(sysctl_vfs_null_setup, "sysctl vfs.null subtree setup") 277 { 278 279 sysctl_createv(clog, 0, NULL, NULL, 280 CTLFLAG_PERMANENT, 281 CTLTYPE_NODE, "vfs", NULL, 282 NULL, 0, NULL, 0, 283 CTL_VFS, CTL_EOL); 284 sysctl_createv(clog, 0, NULL, NULL, 285 CTLFLAG_PERMANENT, 286 CTLTYPE_NODE, "null", NULL, 287 NULL, 0, NULL, 0, 288 CTL_VFS, 9, CTL_EOL); 289 /* 290 * XXX the "9" above could be dynamic, thereby eliminating one 291 * more instance of the "number to vfs" mapping problem, but 292 * "9" is the order as taken from sys/mount.h 293 */ 294 } 295 296 extern const struct vnodeopv_desc null_vnodeop_opv_desc; 297 298 const struct vnodeopv_desc * const nullfs_vnodeopv_descs[] = { 299 &null_vnodeop_opv_desc, 300 NULL, 301 }; 302 303 struct vfsops nullfs_vfsops = { 304 MOUNT_NULL, 305 nullfs_mount, 306 layerfs_start, 307 nullfs_unmount, 308 layerfs_root, 309 layerfs_quotactl, 310 layerfs_statvfs, 311 layerfs_sync, 312 layerfs_vget, 313 layerfs_fhtovp, 314 layerfs_vptofh, 315 layerfs_init, 316 NULL, 317 layerfs_done, 318 NULL, 319 NULL, /* vfs_mountroot */ 320 layerfs_checkexp, 321 nullfs_vnodeopv_descs, 322 }; 323
Indexes created Thu Sep 25 15:09:46 GMT 2025