1 /* $NetBSD: overlay_vfsops.c,v 1.27 2004/07/01 10:03:32 hannken 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. 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 * Overlay Layer 73 * (See overlay_vnops.c for a description of what this does.) 74 */ 75 76 #include <sys/cdefs.h> 77 __KERNEL_RCSID(0, "$NetBSD: overlay_vfsops.c,v 1.27 2004/07/01 10:03:32 hannken 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 #include <miscfs/overlay/overlay.h> 89 #include <miscfs/genfs/layer_extern.h> 90 91 int ov_mount __P((struct mount *, const char *, void *, 92 struct nameidata *, struct proc *)); 93 int ov_unmount __P((struct mount *, int, struct proc *)); 94 95 #define NOVERLAYNODECACHE 16 96 97 /* 98 * Mount overlay layer 99 */ 100 int 101 ov_mount(mp, path, data, ndp, p) 102 struct mount *mp; 103 const char *path; 104 void *data; 105 struct nameidata *ndp; 106 struct proc *p; 107 { 108 int error = 0; 109 struct overlay_args args; 110 struct vnode *lowerrootvp, *vp; 111 struct overlay_mount *nmp; 112 struct layer_mount *lmp; 113 114 #ifdef OVERLAYFS_DIAGNOSTIC 115 printf("ov_mount(mp = %p)\n", mp); 116 #endif 117 118 if (mp->mnt_flag & MNT_GETARGS) { 119 lmp = MOUNTTOLAYERMOUNT(mp); 120 if (lmp == NULL) 121 return EIO; 122 args.la.target = NULL; 123 vfs_showexport(mp, &args.la.export, &lmp->layerm_export); 124 return copyout(&args, data, sizeof(args)); 125 } 126 /* 127 * Get argument 128 */ 129 error = copyin(data, &args, sizeof(struct overlay_args)); 130 if (error) 131 return (error); 132 133 /* 134 * Update only does export updating. 135 */ 136 if (mp->mnt_flag & MNT_UPDATE) { 137 lmp = MOUNTTOLAYERMOUNT(mp); 138 if (args.ova_target == 0) 139 return (vfs_export(mp, &lmp->layerm_export, 140 &args.la.export)); 141 else 142 return (EOPNOTSUPP); 143 } 144 145 /* 146 * Find lower node 147 */ 148 lowerrootvp = mp->mnt_vnodecovered; 149 if ((error = vget(lowerrootvp, LK_EXCLUSIVE | LK_RETRY))) 150 return (error); 151 152 /* 153 * First cut at fixing up upper mount point 154 */ 155 nmp = (struct overlay_mount *) malloc(sizeof(struct overlay_mount), 156 M_UFSMNT, M_WAITOK); /* XXX */ 157 memset(nmp, 0, sizeof(struct overlay_mount)); 158 159 mp->mnt_data = nmp; 160 mp->mnt_leaf = lowerrootvp->v_mount->mnt_leaf; 161 nmp->ovm_vfs = lowerrootvp->v_mount; 162 if (nmp->ovm_vfs->mnt_flag & MNT_LOCAL) 163 mp->mnt_flag |= MNT_LOCAL; 164 165 /* 166 * Make sure that the mount point is sufficiently initialized 167 * that the node create call will work. 168 */ 169 vfs_getnewfsid(mp); 170 171 nmp->ovm_size = sizeof (struct overlay_node); 172 nmp->ovm_tag = VT_OVERLAY; 173 nmp->ovm_bypass = layer_bypass; 174 nmp->ovm_alloc = layer_node_alloc; /* the default alloc is fine */ 175 nmp->ovm_vnodeop_p = overlay_vnodeop_p; 176 simple_lock_init(&nmp->ovm_hashlock); 177 nmp->ovm_node_hashtbl = hashinit(NOVERLAYNODECACHE, HASH_LIST, M_CACHE, 178 M_WAITOK, &nmp->ovm_node_hash); 179 180 /* 181 * Fix up overlay node for root vnode 182 */ 183 error = layer_node_create(mp, lowerrootvp, &vp); 184 /* 185 * Make sure the fixup worked 186 */ 187 if (error) { 188 vput(lowerrootvp); 189 free(nmp, M_UFSMNT); /* XXX */ 190 return (error); 191 } 192 /* 193 * Unlock the node 194 */ 195 VOP_UNLOCK(vp, 0); 196 197 /* 198 * Keep a held reference to the root vnode. 199 * It is vrele'd in ov_unmount. 200 */ 201 vp->v_flag |= VROOT; 202 nmp->ovm_rootvp = vp; 203 204 error = set_statvfs_info(path, UIO_USERSPACE, args.la.target, 205 UIO_USERSPACE, mp, p); 206 #ifdef OVERLAYFS_DIAGNOSTIC 207 printf("ov_mount: lower %s, alias at %s\n", 208 mp->mnt_stat.f_mntfromname, mp->mnt_stat.f_mntonname); 209 #endif 210 return error; 211 } 212 213 /* 214 * Free reference to overlay layer 215 */ 216 int 217 ov_unmount(mp, mntflags, p) 218 struct mount *mp; 219 int mntflags; 220 struct proc *p; 221 { 222 struct vnode *overlay_rootvp = MOUNTTOOVERLAYMOUNT(mp)->ovm_rootvp; 223 int error; 224 int flags = 0; 225 226 #ifdef OVERLAYFS_DIAGNOSTIC 227 printf("ov_unmount(mp = %p)\n", mp); 228 #endif 229 230 if (mntflags & MNT_FORCE) 231 flags |= FORCECLOSE; 232 233 /* 234 * Clear out buffer cache. I don't think we 235 * ever get anything cached at this level at the 236 * moment, but who knows... 237 */ 238 #if 0 239 mntflushbuf(mp, 0); 240 if (mntinvalbuf(mp, 1)) 241 return (EBUSY); 242 #endif 243 if (overlay_rootvp->v_usecount > 1) 244 return (EBUSY); 245 if ((error = vflush(mp, overlay_rootvp, flags)) != 0) 246 return (error); 247 248 #ifdef OVERLAYFS_DIAGNOSTIC 249 vprint("alias root of lower", overlay_rootvp); 250 #endif 251 /* 252 * Release reference on underlying root vnode 253 */ 254 vrele(overlay_rootvp); 255 /* 256 * And blow it away for future re-use 257 */ 258 vgone(overlay_rootvp); 259 /* 260 * Finally, throw away the overlay_mount structure 261 */ 262 free(mp->mnt_data, M_UFSMNT); /* XXX */ 263 mp->mnt_data = 0; 264 return 0; 265 } 266 267 SYSCTL_SETUP(sysctl_vfs_overlay_setup, "sysctl vfs.overlay subtree setup") 268 { 269 270 sysctl_createv(clog, 0, NULL, NULL, 271 CTLFLAG_PERMANENT, CTLTYPE_NODE, "vfs", NULL, 272 NULL, 0, NULL, 0, 273 CTL_VFS, CTL_EOL); 274 sysctl_createv(clog, 0, NULL, NULL, 275 CTLFLAG_PERMANENT, CTLTYPE_NODE, "overlay", 276 SYSCTL_DESCR("Overlay file system"), 277 NULL, 0, NULL, 0, 278 CTL_VFS, CTL_CREATE, CTL_EOL); 279 } 280 281 extern const struct vnodeopv_desc overlay_vnodeop_opv_desc; 282 283 const struct vnodeopv_desc * const ov_vnodeopv_descs[] = { 284 &overlay_vnodeop_opv_desc, 285 NULL, 286 }; 287 288 struct vfsops overlay_vfsops = { 289 MOUNT_OVERLAY, 290 ov_mount, 291 layerfs_start, 292 ov_unmount, 293 layerfs_root, 294 layerfs_quotactl, 295 layerfs_statvfs, 296 layerfs_sync, 297 layerfs_vget, 298 layerfs_fhtovp, 299 layerfs_vptofh, 300 layerfs_init, 301 NULL, 302 layerfs_done, 303 NULL, 304 NULL, /* vfs_mountroot */ 305 layerfs_checkexp, 306 layerfs_snapshot, 307 ov_vnodeopv_descs, 308 }; 309