overlay_vfsops.c revision 1.64
1 /* $NetBSD: overlay_vfsops.c,v 1.64 2017/02/17 08:31:25 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 1.64 2017/02/17 08:31:25 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/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 = layerfs_suspendctl, 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
Indexes created Mon Sep 29 21:09:56 GMT 2025