overlay_vfsops.c revision 1.52
1 /* $NetBSD: overlay_vfsops.c,v 1.52 2008/05/13 08:31:13 simonb 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 1.52 2008/05/13 08:31:13 simonb 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 <sys/module.h> 89 #include <miscfs/overlay/overlay.h> 90 #include <miscfs/genfs/layer_extern.h> 91 92 MODULE(MODULE_CLASS_VFS, overlay, NULL); 93 94 VFS_PROTOS(ov); 95 96 #define NOVERLAYNODECACHE 16 97 98 /* 99 * Mount overlay layer 100 */ 101 int 102 ov_mount(struct mount *mp, const char *path, void *data, size_t *data_len) 103 { 104 struct lwp *l = curlwp; 105 int error = 0; 106 struct overlay_args *args = data; 107 struct vnode *lowerrootvp, *vp; 108 struct overlay_mount *nmp; 109 struct layer_mount *lmp; 110 111 #ifdef OVERLAYFS_DIAGNOSTIC 112 printf("ov_mount(mp = %p)\n", mp); 113 #endif 114 115 if (*data_len < sizeof *args) 116 return EINVAL; 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 *data_len = sizeof *args; 124 return 0; 125 } 126 127 /* 128 * Update is not supported 129 */ 130 if (mp->mnt_flag & MNT_UPDATE) 131 return EOPNOTSUPP; 132 133 /* 134 * Find lower node 135 */ 136 lowerrootvp = mp->mnt_vnodecovered; 137 if ((error = vget(lowerrootvp, LK_EXCLUSIVE | LK_RETRY))) 138 return (error); 139 140 /* 141 * First cut at fixing up upper mount point 142 */ 143 nmp = (struct overlay_mount *) malloc(sizeof(struct overlay_mount), 144 M_UFSMNT, M_WAITOK); /* XXX */ 145 memset(nmp, 0, sizeof(struct overlay_mount)); 146 147 mp->mnt_data = nmp; 148 nmp->ovm_vfs = lowerrootvp->v_mount; 149 if (nmp->ovm_vfs->mnt_flag & MNT_LOCAL) 150 mp->mnt_flag |= MNT_LOCAL; 151 152 /* 153 * Make sure that the mount point is sufficiently initialized 154 * that the node create call will work. 155 */ 156 vfs_getnewfsid(mp); 157 158 nmp->ovm_size = sizeof (struct overlay_node); 159 nmp->ovm_tag = VT_OVERLAY; 160 nmp->ovm_bypass = layer_bypass; 161 nmp->ovm_alloc = layer_node_alloc; /* the default alloc is fine */ 162 nmp->ovm_vnodeop_p = overlay_vnodeop_p; 163 mutex_init(&nmp->ovm_hashlock, MUTEX_DEFAULT, IPL_NONE); 164 nmp->ovm_node_hashtbl = hashinit(NOVERLAYNODECACHE, HASH_LIST, true, 165 &nmp->ovm_node_hash); 166 167 /* 168 * Fix up overlay node for root vnode 169 */ 170 error = layer_node_create(mp, lowerrootvp, &vp); 171 /* 172 * Make sure the fixup worked 173 */ 174 if (error) { 175 vput(lowerrootvp); 176 hashdone(nmp->ovm_node_hashtbl, HASH_LIST, nmp->ovm_node_hash); 177 free(nmp, M_UFSMNT); /* XXX */ 178 return (error); 179 } 180 /* 181 * Unlock the node 182 */ 183 VOP_UNLOCK(vp, 0); 184 185 /* 186 * Keep a held reference to the root vnode. 187 * It is vrele'd in ov_unmount. 188 */ 189 vp->v_vflag |= VV_ROOT; 190 nmp->ovm_rootvp = vp; 191 192 error = set_statvfs_info(path, UIO_USERSPACE, args->la.target, 193 UIO_USERSPACE, mp->mnt_op->vfs_name, mp, l); 194 #ifdef OVERLAYFS_DIAGNOSTIC 195 printf("ov_mount: lower %s, alias at %s\n", 196 mp->mnt_stat.f_mntfromname, mp->mnt_stat.f_mntonname); 197 #endif 198 return error; 199 } 200 201 /* 202 * Free reference to overlay layer 203 */ 204 int 205 ov_unmount(struct mount *mp, int mntflags) 206 { 207 struct vnode *overlay_rootvp = MOUNTTOOVERLAYMOUNT(mp)->ovm_rootvp; 208 struct overlay_mount *omp; 209 int error; 210 int flags = 0; 211 212 #ifdef OVERLAYFS_DIAGNOSTIC 213 printf("ov_unmount(mp = %p)\n", mp); 214 #endif 215 216 if (mntflags & MNT_FORCE) 217 flags |= FORCECLOSE; 218 219 if (overlay_rootvp->v_usecount > 1 && (mntflags & MNT_FORCE) == 0) 220 return (EBUSY); 221 if ((error = vflush(mp, overlay_rootvp, flags)) != 0) 222 return (error); 223 224 #ifdef OVERLAYFS_DIAGNOSTIC 225 vprint("alias root of lower", overlay_rootvp); 226 #endif 227 /* 228 * Blow it away for future re-use 229 */ 230 vgone(overlay_rootvp); 231 /* 232 * Finally, throw away the overlay_mount structure 233 */ 234 omp = mp->mnt_data; 235 mutex_destroy(&omp->ovm_hashlock); 236 hashdone(omp->ovm_node_hashtbl, HASH_LIST, omp->ovm_node_hash); 237 free(omp, M_UFSMNT); /* XXX */ 238 mp->mnt_data = NULL; 239 return 0; 240 } 241 242 SYSCTL_SETUP(sysctl_vfs_overlay_setup, "sysctl vfs.overlay subtree setup") 243 { 244 245 sysctl_createv(clog, 0, NULL, NULL, 246 CTLFLAG_PERMANENT, CTLTYPE_NODE, "vfs", NULL, 247 NULL, 0, NULL, 0, 248 CTL_VFS, CTL_EOL); 249 sysctl_createv(clog, 0, NULL, NULL, 250 CTLFLAG_PERMANENT, CTLTYPE_NODE, "overlay", 251 SYSCTL_DESCR("Overlay file system"), 252 NULL, 0, NULL, 0, 253 CTL_VFS, CTL_CREATE, CTL_EOL); 254 } 255 256 extern const struct vnodeopv_desc overlay_vnodeop_opv_desc; 257 258 const struct vnodeopv_desc * const ov_vnodeopv_descs[] = { 259 &overlay_vnodeop_opv_desc, 260 NULL, 261 }; 262 263 struct vfsops overlay_vfsops = { 264 MOUNT_OVERLAY, 265 sizeof (struct overlay_args), 266 ov_mount, 267 layerfs_start, 268 ov_unmount, 269 layerfs_root, 270 layerfs_quotactl, 271 layerfs_statvfs, 272 layerfs_sync, 273 layerfs_vget, 274 layerfs_fhtovp, 275 layerfs_vptofh, 276 layerfs_init, 277 NULL, 278 layerfs_done, 279 NULL, /* vfs_mountroot */ 280 layerfs_snapshot, 281 vfs_stdextattrctl, 282 (void *)eopnotsupp, /* vfs_suspendctl */ 283 layerfs_renamelock_enter, 284 layerfs_renamelock_exit, 285 (void *)eopnotsupp, 286 ov_vnodeopv_descs, 287 0, 288 { NULL, NULL }, 289 }; 290 291 static int 292 overlay_modcmd(modcmd_t cmd, void *arg) 293 { 294 295 switch (cmd) { 296 case MODULE_CMD_INIT: 297 return vfs_attach(&overlay_vfsops); 298 case MODULE_CMD_FINI: 299 return vfs_detach(&overlay_vfsops); 300 default: 301 return ENOTTY; 302 } 303 } 304
Indexes created Mon Sep 29 21:09:56 GMT 2025