overlay_vfsops.c revision 1.56.14.1
1 /* $NetBSD: overlay_vfsops.c,v 1.56.14.1 2014/04/21 10:14:18 bouyer 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 1.56.14.1 2014/04/21 10:14:18 bouyer 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, "layerfs"); 93 94 VFS_PROTOS(ov); 95 96 static struct sysctllog *overlay_sysctl_log; 97 98 #define NOVERLAYNODECACHE 16 99 100 /* 101 * Mount overlay layer 102 */ 103 int 104 ov_mount(struct mount *mp, const char *path, void *data, size_t *data_len) 105 { 106 struct lwp *l = curlwp; 107 int error = 0; 108 struct overlay_args *args = data; 109 struct vnode *lowerrootvp, *vp; 110 struct overlay_mount *nmp; 111 struct layer_mount *lmp; 112 113 #ifdef OVERLAYFS_DIAGNOSTIC 114 printf("ov_mount(mp = %p)\n", mp); 115 #endif 116 117 if (args == NULL) 118 return EINVAL; 119 if (*data_len < sizeof *args) 120 return EINVAL; 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 *data_len = sizeof *args; 128 return 0; 129 } 130 131 /* 132 * Update is not supported 133 */ 134 if (mp->mnt_flag & MNT_UPDATE) 135 return EOPNOTSUPP; 136 137 /* 138 * Find lower node 139 */ 140 lowerrootvp = mp->mnt_vnodecovered; 141 vref(lowerrootvp); 142 if ((error = vn_lock(lowerrootvp, LK_EXCLUSIVE | LK_RETRY))) { 143 vrele(lowerrootvp); 144 return (error); 145 } 146 147 /* 148 * First cut at fixing up upper mount point 149 */ 150 nmp = (struct overlay_mount *) malloc(sizeof(struct overlay_mount), 151 M_UFSMNT, M_WAITOK); /* XXX */ 152 memset(nmp, 0, sizeof(struct overlay_mount)); 153 154 mp->mnt_data = nmp; 155 nmp->ovm_vfs = lowerrootvp->v_mount; 156 if (nmp->ovm_vfs->mnt_flag & MNT_LOCAL) 157 mp->mnt_flag |= MNT_LOCAL; 158 159 /* 160 * Make sure that the mount point is sufficiently initialized 161 * that the node create call will work. 162 */ 163 vfs_getnewfsid(mp); 164 165 nmp->ovm_size = sizeof (struct overlay_node); 166 nmp->ovm_tag = VT_OVERLAY; 167 nmp->ovm_bypass = layer_bypass; 168 nmp->ovm_alloc = layer_node_alloc; /* the default alloc is fine */ 169 nmp->ovm_vnodeop_p = overlay_vnodeop_p; 170 mutex_init(&nmp->ovm_hashlock, MUTEX_DEFAULT, IPL_NONE); 171 nmp->ovm_node_hashtbl = hashinit(NOVERLAYNODECACHE, HASH_LIST, true, 172 &nmp->ovm_node_hash); 173 174 /* 175 * Fix up overlay node for root vnode 176 */ 177 error = layer_node_create(mp, lowerrootvp, &vp); 178 /* 179 * Make sure the fixup worked 180 */ 181 if (error) { 182 vput(lowerrootvp); 183 hashdone(nmp->ovm_node_hashtbl, HASH_LIST, nmp->ovm_node_hash); 184 free(nmp, M_UFSMNT); /* XXX */ 185 return (error); 186 } 187 /* 188 * Unlock the node 189 */ 190 VOP_UNLOCK(vp); 191 192 /* 193 * Keep a held reference to the root vnode. 194 * It is vrele'd in ov_unmount. 195 */ 196 vp->v_vflag |= VV_ROOT; 197 nmp->ovm_rootvp = vp; 198 199 error = set_statvfs_info(path, UIO_USERSPACE, args->la.target, 200 UIO_USERSPACE, mp->mnt_op->vfs_name, mp, l); 201 #ifdef OVERLAYFS_DIAGNOSTIC 202 printf("ov_mount: lower %s, alias at %s\n", 203 mp->mnt_stat.f_mntfromname, mp->mnt_stat.f_mntonname); 204 #endif 205 return error; 206 } 207 208 /* 209 * Free reference to overlay layer 210 */ 211 int 212 ov_unmount(struct mount *mp, int mntflags) 213 { 214 struct vnode *overlay_rootvp = MOUNTTOOVERLAYMOUNT(mp)->ovm_rootvp; 215 struct overlay_mount *omp; 216 int error; 217 int flags = 0; 218 219 #ifdef OVERLAYFS_DIAGNOSTIC 220 printf("ov_unmount(mp = %p)\n", mp); 221 #endif 222 223 if (mntflags & MNT_FORCE) 224 flags |= FORCECLOSE; 225 226 if (overlay_rootvp->v_usecount > 1 && (mntflags & MNT_FORCE) == 0) 227 return (EBUSY); 228 if ((error = vflush(mp, overlay_rootvp, flags)) != 0) 229 return (error); 230 231 #ifdef OVERLAYFS_DIAGNOSTIC 232 vprint("alias root of lower", overlay_rootvp); 233 #endif 234 /* 235 * Blow it away for future re-use 236 */ 237 vgone(overlay_rootvp); 238 /* 239 * Finally, throw away the overlay_mount structure 240 */ 241 omp = mp->mnt_data; 242 mutex_destroy(&omp->ovm_hashlock); 243 hashdone(omp->ovm_node_hashtbl, HASH_LIST, omp->ovm_node_hash); 244 free(omp, M_UFSMNT); /* XXX */ 245 mp->mnt_data = NULL; 246 return 0; 247 } 248 249 extern const struct vnodeopv_desc overlay_vnodeop_opv_desc; 250 251 const struct vnodeopv_desc * const ov_vnodeopv_descs[] = { 252 &overlay_vnodeop_opv_desc, 253 NULL, 254 }; 255 256 struct vfsops overlay_vfsops = { 257 MOUNT_OVERLAY, 258 sizeof (struct overlay_args), 259 ov_mount, 260 layerfs_start, 261 ov_unmount, 262 layerfs_root, 263 layerfs_quotactl, 264 layerfs_statvfs, 265 layerfs_sync, 266 layerfs_vget, 267 layerfs_fhtovp, 268 layerfs_vptofh, 269 layerfs_init, 270 NULL, 271 layerfs_done, 272 NULL, /* vfs_mountroot */ 273 layerfs_snapshot, 274 vfs_stdextattrctl, 275 (void *)eopnotsupp, /* vfs_suspendctl */ 276 layerfs_renamelock_enter, 277 layerfs_renamelock_exit, 278 (void *)eopnotsupp, 279 ov_vnodeopv_descs, 280 0, 281 { NULL, NULL }, 282 }; 283 284 static int 285 overlay_modcmd(modcmd_t cmd, void *arg) 286 { 287 int error; 288 289 switch (cmd) { 290 case MODULE_CMD_INIT: 291 error = vfs_attach(&overlay_vfsops); 292 if (error != 0) 293 break; 294 sysctl_createv(&overlay_sysctl_log, 0, NULL, NULL, 295 CTLFLAG_PERMANENT, CTLTYPE_NODE, "vfs", NULL, 296 NULL, 0, NULL, 0, 297 CTL_VFS, CTL_EOL); 298 sysctl_createv(&overlay_sysctl_log, 0, NULL, NULL, 299 CTLFLAG_PERMANENT, CTLTYPE_NODE, "overlay", 300 SYSCTL_DESCR("Overlay file system"), 301 NULL, 0, NULL, 0, 302 CTL_VFS, CTL_CREATE, CTL_EOL); 303 break; 304 case MODULE_CMD_FINI: 305 error = vfs_detach(&overlay_vfsops); 306 if (error != 0) 307 break; 308 sysctl_teardown(&overlay_sysctl_log); 309 break; 310 default: 311 error = ENOTTY; 312 break; 313 } 314 315 return (error); 316 } 317
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