1 /* $NetBSD: overlay_vfsops.c,v 1.12 2002/09/21 18:09:29 christos Exp $ */ 2 3 /* 4 * Copyright (c) 1999, 2000 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. All advertising materials mentioning features or use of this software 51 * must display the following acknowledgement: 52 * This product includes software developed by the University of 53 * California, Berkeley and its contributors. 54 * 4. Neither the name of the University nor the names of its contributors 55 * may be used to endorse or promote products derived from this software 56 * without specific prior written permission. 57 * 58 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 59 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 60 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 61 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 62 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 63 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 64 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 65 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 66 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 67 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 68 * SUCH DAMAGE. 69 * 70 * from: Id: lofs_vfsops.c,v 1.9 1992/05/30 10:26:24 jsp Exp 71 * from: @(#)lofs_vfsops.c 1.2 (Berkeley) 6/18/92 72 * @(#)null_vfsops.c 8.7 (Berkeley) 5/14/95 73 */ 74 75 /* 76 * Overlay Layer 77 * (See overlay_vnops.c for a description of what this does.) 78 */ 79 80 #include <sys/cdefs.h> 81 __KERNEL_RCSID(0, "$NetBSD: overlay_vfsops.c,v 1.12 2002/09/21 18:09:29 christos Exp $"); 82 83 #include <sys/param.h> 84 #include <sys/systm.h> 85 #include <sys/time.h> 86 #include <sys/proc.h> 87 #include <sys/vnode.h> 88 #include <sys/mount.h> 89 #include <sys/namei.h> 90 #include <sys/malloc.h> 91 #include <miscfs/overlay/overlay.h> 92 #include <miscfs/genfs/layer_extern.h> 93 94 int ov_mount __P((struct mount *, const char *, void *, 95 struct nameidata *, struct proc *)); 96 int ov_unmount __P((struct mount *, int, struct proc *)); 97 98 #define NOVERLAYNODECACHE 16 99 100 /* 101 * Mount overlay layer 102 */ 103 int 104 ov_mount(mp, path, data, ndp, p) 105 struct mount *mp; 106 const char *path; 107 void *data; 108 struct nameidata *ndp; 109 struct proc *p; 110 { 111 int error = 0; 112 struct overlay_args args; 113 struct vnode *lowerrootvp, *vp; 114 struct overlay_mount *nmp; 115 struct layer_mount *lmp; 116 size_t size; 117 118 #ifdef OVERLAYFS_DIAGNOSTIC 119 printf("ov_mount(mp = %p)\n", mp); 120 #endif 121 122 if (mp->mnt_flag & MNT_GETARGS) { 123 lmp = MOUNTTOLAYERMOUNT(mp); 124 if (lmp == NULL) 125 return EIO; 126 args.la.target = NULL; 127 vfs_showexport(mp, &args.la.export, &lmp->layerm_export); 128 return copyout(&args, data, sizeof(args)); 129 } 130 /* 131 * Get argument 132 */ 133 error = copyin(data, (caddr_t)&args, sizeof(struct overlay_args)); 134 if (error) 135 return (error); 136 137 /* 138 * Update only does export updating. 139 */ 140 if (mp->mnt_flag & MNT_UPDATE) { 141 lmp = MOUNTTOLAYERMOUNT(mp); 142 if (args.ova_target == 0) 143 return (vfs_export(mp, &lmp->layerm_export, 144 &args.la.export)); 145 else 146 return (EOPNOTSUPP); 147 } 148 149 /* 150 * Find lower node 151 */ 152 lowerrootvp = mp->mnt_vnodecovered; 153 if ((error = vget(lowerrootvp, LK_EXCLUSIVE | LK_RETRY))) 154 return (error); 155 156 /* 157 * First cut at fixing up upper mount point 158 */ 159 nmp = (struct overlay_mount *) malloc(sizeof(struct overlay_mount), 160 M_UFSMNT, M_WAITOK); /* XXX */ 161 memset((caddr_t)nmp, 0, sizeof(struct overlay_mount)); 162 163 mp->mnt_data = nmp; 164 nmp->ovm_vfs = lowerrootvp->v_mount; 165 if (nmp->ovm_vfs->mnt_flag & MNT_LOCAL) 166 mp->mnt_flag |= MNT_LOCAL; 167 168 /* 169 * Make sure that the mount point is sufficiently initialized 170 * that the node create call will work. 171 */ 172 vfs_getnewfsid(mp); 173 174 nmp->ovm_size = sizeof (struct overlay_node); 175 nmp->ovm_tag = VT_OVERLAY; 176 nmp->ovm_bypass = layer_bypass; 177 nmp->ovm_alloc = layer_node_alloc; /* the default alloc is fine */ 178 nmp->ovm_vnodeop_p = overlay_vnodeop_p; 179 simple_lock_init(&nmp->ovm_hashlock); 180 nmp->ovm_node_hashtbl = hashinit(NOVERLAYNODECACHE, HASH_LIST, M_CACHE, 181 M_WAITOK, &nmp->ovm_node_hash); 182 183 /* 184 * Fix up overlay node for root vnode 185 */ 186 error = layer_node_create(mp, lowerrootvp, &vp); 187 /* 188 * Make sure the fixup worked 189 */ 190 if (error) { 191 vput(lowerrootvp); 192 free(nmp, M_UFSMNT); /* XXX */ 193 return (error); 194 } 195 /* 196 * Unlock the node 197 */ 198 VOP_UNLOCK(vp, 0); 199 200 /* 201 * Keep a held reference to the root vnode. 202 * It is vrele'd in ov_unmount. 203 */ 204 vp->v_flag |= VROOT; 205 nmp->ovm_rootvp = vp; 206 207 (void) copyinstr(path, mp->mnt_stat.f_mntonname, MNAMELEN - 1, &size); 208 memset(mp->mnt_stat.f_mntonname + size, 0, MNAMELEN - size); 209 (void) copyinstr(args.la.target, mp->mnt_stat.f_mntfromname, MNAMELEN - 1, 210 &size); 211 memset(mp->mnt_stat.f_mntfromname + size, 0, MNAMELEN - size); 212 #ifdef OVERLAYFS_DIAGNOSTIC 213 printf("ov_mount: lower %s, alias at %s\n", 214 mp->mnt_stat.f_mntfromname, mp->mnt_stat.f_mntonname); 215 #endif 216 return (0); 217 } 218 219 /* 220 * Free reference to overlay layer 221 */ 222 int 223 ov_unmount(mp, mntflags, p) 224 struct mount *mp; 225 int mntflags; 226 struct proc *p; 227 { 228 struct vnode *overlay_rootvp = MOUNTTOOVERLAYMOUNT(mp)->ovm_rootvp; 229 int error; 230 int flags = 0; 231 232 #ifdef OVERLAYFS_DIAGNOSTIC 233 printf("ov_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 (overlay_rootvp->v_usecount > 1) 250 return (EBUSY); 251 if ((error = vflush(mp, overlay_rootvp, flags)) != 0) 252 return (error); 253 254 #ifdef OVERLAYFS_DIAGNOSTIC 255 vprint("alias root of lower", overlay_rootvp); 256 #endif 257 /* 258 * Release reference on underlying root vnode 259 */ 260 vrele(overlay_rootvp); 261 /* 262 * And blow it away for future re-use 263 */ 264 vgone(overlay_rootvp); 265 /* 266 * Finally, throw away the overlay_mount structure 267 */ 268 free(mp->mnt_data, M_UFSMNT); /* XXX */ 269 mp->mnt_data = 0; 270 return 0; 271 } 272 273 extern const struct vnodeopv_desc overlay_vnodeop_opv_desc; 274 275 const struct vnodeopv_desc * const ov_vnodeopv_descs[] = { 276 &overlay_vnodeop_opv_desc, 277 NULL, 278 }; 279 280 struct vfsops overlay_vfsops = { 281 MOUNT_OVERLAY, 282 ov_mount, 283 layerfs_start, 284 ov_unmount, 285 layerfs_root, 286 layerfs_quotactl, 287 layerfs_statfs, 288 layerfs_sync, 289 layerfs_vget, 290 layerfs_fhtovp, 291 layerfs_vptofh, 292 layerfs_init, 293 NULL, 294 layerfs_done, 295 layerfs_sysctl, 296 NULL, /* vfs_mountroot */ 297 layerfs_checkexp, 298 ov_vnodeopv_descs, 299 }; 300