| 1 | /* $NetBSD: overlay_vfsops.c,v 1.63 2014/11/10 18:46:33 maxv 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 1.63 2014/11/10 18:46:33 maxv 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/module.h> |
| 88 | #include <miscfs/overlay/overlay.h> |
| 89 | #include <miscfs/genfs/layer_extern.h> |
| 90 | |
| 91 | MODULE(MODULE_CLASS_VFS, overlay, "layerfs" ); |
| 92 | |
| 93 | VFS_PROTOS(ov); |
| 94 | |
| 95 | static struct sysctllog *overlay_sysctl_log; |
| 96 | |
| 97 | #define NOVERLAYNODECACHE 16 |
| 98 | |
| 99 | /* |
| 100 | * Mount overlay layer |
| 101 | */ |
| 102 | int |
| 103 | ov_mount(struct mount *mp, const char *path, void *data, size_t *data_len) |
| 104 | { |
| 105 | struct lwp *l = curlwp; |
| 106 | int error = 0; |
| 107 | struct overlay_args *args = data; |
| 108 | struct vnode *lowerrootvp, *vp; |
| 109 | struct overlay_mount *nmp; |
| 110 | struct layer_mount *lmp; |
| 111 | |
| 112 | #ifdef OVERLAYFS_DIAGNOSTIC |
| 113 | printf("ov_mount(mp = %p)\n" , mp); |
| 114 | #endif |
| 115 | |
| 116 | if (args == NULL) |
| 117 | return EINVAL; |
| 118 | if (*data_len < sizeof *args) |
| 119 | return EINVAL; |
| 120 | |
| 121 | if (mp->mnt_flag & MNT_GETARGS) { |
| 122 | lmp = MOUNTTOLAYERMOUNT(mp); |
| 123 | if (lmp == NULL) |
| 124 | return EIO; |
| 125 | args->la.target = NULL; |
| 126 | *data_len = sizeof *args; |
| 127 | return 0; |
| 128 | } |
| 129 | |
| 130 | /* |
| 131 | * Update is not supported |
| 132 | */ |
| 133 | if (mp->mnt_flag & MNT_UPDATE) |
| 134 | return EOPNOTSUPP; |
| 135 | |
| 136 | /* |
| 137 | * Find lower node |
| 138 | */ |
| 139 | lowerrootvp = mp->mnt_vnodecovered; |
| 140 | vref(lowerrootvp); |
| 141 | if ((error = vn_lock(lowerrootvp, LK_EXCLUSIVE | LK_RETRY))) { |
| 142 | vrele(lowerrootvp); |
| 143 | return (error); |
| 144 | } |
| 145 | |
| 146 | /* |
| 147 | * First cut at fixing up upper mount point |
| 148 | */ |
| 149 | nmp = kmem_zalloc(sizeof(struct overlay_mount), KM_SLEEP); |
| 150 | |
| 151 | mp->mnt_data = nmp; |
| 152 | nmp->ovm_vfs = lowerrootvp->v_mount; |
| 153 | if (nmp->ovm_vfs->mnt_flag & MNT_LOCAL) |
| 154 | mp->mnt_flag |= MNT_LOCAL; |
| 155 | |
| 156 | /* |
| 157 | * Make sure that the mount point is sufficiently initialized |
| 158 | * that the node create call will work. |
| 159 | */ |
| 160 | vfs_getnewfsid(mp); |
| 161 | |
| 162 | nmp->ovm_size = sizeof (struct overlay_node); |
| 163 | nmp->ovm_tag = VT_OVERLAY; |
| 164 | nmp->ovm_bypass = layer_bypass; |
| 165 | nmp->ovm_vnodeop_p = overlay_vnodeop_p; |
| 166 | |
| 167 | /* |
| 168 | * Fix up overlay node for root vnode |
| 169 | */ |
| 170 | VOP_UNLOCK(lowerrootvp); |
| 171 | error = layer_node_create(mp, lowerrootvp, &vp); |
| 172 | /* |
| 173 | * Make sure the fixup worked |
| 174 | */ |
| 175 | if (error) { |
| 176 | vrele(lowerrootvp); |
| 177 | kmem_free(nmp, sizeof(struct overlay_mount)); |
| 178 | return error; |
| 179 | } |
| 180 | |
| 181 | /* |
| 182 | * Keep a held reference to the root vnode. |
| 183 | * It is vrele'd in ov_unmount. |
| 184 | */ |
| 185 | vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); |
| 186 | vp->v_vflag |= VV_ROOT; |
| 187 | nmp->ovm_rootvp = vp; |
| 188 | VOP_UNLOCK(vp); |
| 189 | |
| 190 | error = set_statvfs_info(path, UIO_USERSPACE, args->la.target, |
| 191 | UIO_USERSPACE, mp->mnt_op->vfs_name, mp, l); |
| 192 | #ifdef OVERLAYFS_DIAGNOSTIC |
| 193 | printf("ov_mount: lower %s, alias at %s\n" , |
| 194 | mp->mnt_stat.f_mntfromname, mp->mnt_stat.f_mntonname); |
| 195 | #endif |
| 196 | return error; |
| 197 | } |
| 198 | |
| 199 | /* |
| 200 | * Free reference to overlay layer |
| 201 | */ |
| 202 | int |
| 203 | ov_unmount(struct mount *mp, int mntflags) |
| 204 | { |
| 205 | struct vnode *overlay_rootvp = MOUNTTOOVERLAYMOUNT(mp)->ovm_rootvp; |
| 206 | struct overlay_mount *omp; |
| 207 | int error; |
| 208 | int flags = 0; |
| 209 | |
| 210 | #ifdef OVERLAYFS_DIAGNOSTIC |
| 211 | printf("ov_unmount(mp = %p)\n" , mp); |
| 212 | #endif |
| 213 | |
| 214 | if (mntflags & MNT_FORCE) |
| 215 | flags |= FORCECLOSE; |
| 216 | |
| 217 | if (overlay_rootvp->v_usecount > 1 && (mntflags & MNT_FORCE) == 0) |
| 218 | return (EBUSY); |
| 219 | if ((error = vflush(mp, overlay_rootvp, flags)) != 0) |
| 220 | return (error); |
| 221 | |
| 222 | #ifdef OVERLAYFS_DIAGNOSTIC |
| 223 | vprint("alias root of lower" , overlay_rootvp); |
| 224 | #endif |
| 225 | /* |
| 226 | * Blow it away for future re-use |
| 227 | */ |
| 228 | vgone(overlay_rootvp); |
| 229 | /* |
| 230 | * Finally, throw away the overlay_mount structure |
| 231 | */ |
| 232 | omp = mp->mnt_data; |
| 233 | kmem_free(omp, sizeof(struct overlay_mount)); |
| 234 | mp->mnt_data = NULL; |
| 235 | return 0; |
| 236 | } |
| 237 | |
| 238 | extern const struct vnodeopv_desc overlay_vnodeop_opv_desc; |
| 239 | |
| 240 | const struct vnodeopv_desc * const ov_vnodeopv_descs[] = { |
| 241 | &overlay_vnodeop_opv_desc, |
| 242 | NULL, |
| 243 | }; |
| 244 | |
| 245 | struct vfsops overlay_vfsops = { |
| 246 | .vfs_name = MOUNT_OVERLAY, |
| 247 | .vfs_min_mount_data = sizeof (struct overlay_args), |
| 248 | .vfs_mount = ov_mount, |
| 249 | .vfs_start = layerfs_start, |
| 250 | .vfs_unmount = ov_unmount, |
| 251 | .vfs_root = layerfs_root, |
| 252 | .vfs_quotactl = layerfs_quotactl, |
| 253 | .vfs_statvfs = layerfs_statvfs, |
| 254 | .vfs_sync = layerfs_sync, |
| 255 | .vfs_loadvnode = layerfs_loadvnode, |
| 256 | .vfs_vget = layerfs_vget, |
| 257 | .vfs_fhtovp = layerfs_fhtovp, |
| 258 | .vfs_vptofh = layerfs_vptofh, |
| 259 | .vfs_init = layerfs_init, |
| 260 | .vfs_done = layerfs_done, |
| 261 | .vfs_snapshot = layerfs_snapshot, |
| 262 | .vfs_extattrctl = vfs_stdextattrctl, |
| 263 | .vfs_suspendctl = (void *)eopnotsupp, |
| 264 | .vfs_renamelock_enter = layerfs_renamelock_enter, |
| 265 | .vfs_renamelock_exit = layerfs_renamelock_exit, |
| 266 | .vfs_fsync = (void *)eopnotsupp, |
| 267 | .vfs_opv_descs = ov_vnodeopv_descs |
| 268 | }; |
| 269 | |
| 270 | static int |
| 271 | overlay_modcmd(modcmd_t cmd, void *arg) |
| 272 | { |
| 273 | int error; |
| 274 | |
| 275 | switch (cmd) { |
| 276 | case MODULE_CMD_INIT: |
| 277 | error = vfs_attach(&overlay_vfsops); |
| 278 | if (error != 0) |
| 279 | break; |
| 280 | sysctl_createv(&overlay_sysctl_log, 0, NULL, NULL, |
| 281 | CTLFLAG_PERMANENT, CTLTYPE_NODE, "overlay" , |
| 282 | SYSCTL_DESCR("Overlay file system" ), |
| 283 | NULL, 0, NULL, 0, |
| 284 | CTL_VFS, CTL_CREATE, CTL_EOL); |
| 285 | break; |
| 286 | case MODULE_CMD_FINI: |
| 287 | error = vfs_detach(&overlay_vfsops); |
| 288 | if (error != 0) |
| 289 | break; |
| 290 | sysctl_teardown(&overlay_sysctl_log); |
| 291 | break; |
| 292 | default: |
| 293 | error = ENOTTY; |
| 294 | break; |
| 295 | } |
| 296 | |
| 297 | return (error); |
| 298 | } |
| 299 | |