overlay_vfsops.c revision 1.71
1 /* $NetBSD: overlay_vfsops.c,v 1.71 2020/04/13 19:23:19 ad 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 1.71 2020/04/13 19:23:19 ad 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 #define NOVERLAYNODECACHE 16 96 97 /* 98 * Mount overlay layer 99 */ 100 int 101 ov_mount(struct mount *mp, const char *path, void *data, size_t *data_len) 102 { 103 struct lwp *l = curlwp; 104 int error = 0; 105 struct overlay_args *args = data; 106 struct vnode *lowerrootvp, *vp; 107 struct overlay_mount *nmp; 108 struct layer_mount *lmp; 109 110 #ifdef OVERLAYFS_DIAGNOSTIC 111 printf("ov_mount(mp = %p)\n", mp); 112 #endif 113 114 if (args == NULL) 115 return EINVAL; 116 if (*data_len < sizeof *args) 117 return EINVAL; 118 119 if (mp->mnt_flag & MNT_GETARGS) { 120 lmp = MOUNTTOLAYERMOUNT(mp); 121 if (lmp == NULL) 122 return EIO; 123 args->la.target = NULL; 124 *data_len = sizeof *args; 125 return 0; 126 } 127 128 /* 129 * Update is not supported 130 */ 131 if (mp->mnt_flag & MNT_UPDATE) 132 return EOPNOTSUPP; 133 134 /* 135 * Find lower node 136 */ 137 lowerrootvp = mp->mnt_vnodecovered; 138 vref(lowerrootvp); 139 if ((error = vn_lock(lowerrootvp, LK_EXCLUSIVE | LK_RETRY))) { 140 vrele(lowerrootvp); 141 return (error); 142 } 143 144 /* 145 * First cut at fixing up upper mount point 146 */ 147 nmp = kmem_zalloc(sizeof(struct overlay_mount), KM_SLEEP); 148 149 mp->mnt_data = nmp; 150 151 /* 152 * Make sure that the mount point is sufficiently initialized 153 * that the node create call will work. 154 */ 155 vfs_getnewfsid(mp); 156 mp->mnt_lower = lowerrootvp->v_mount; 157 158 nmp->ovm_size = sizeof (struct overlay_node); 159 nmp->ovm_tag = VT_OVERLAY; 160 nmp->ovm_bypass = layer_bypass; 161 nmp->ovm_vnodeop_p = overlay_vnodeop_p; 162 163 /* 164 * Fix up overlay node for root vnode 165 */ 166 VOP_UNLOCK(lowerrootvp); 167 error = layer_node_create(mp, lowerrootvp, &vp); 168 /* 169 * Make sure the fixup worked 170 */ 171 if (error) { 172 vrele(lowerrootvp); 173 kmem_free(nmp, sizeof(struct overlay_mount)); 174 return error; 175 } 176 177 /* 178 * Keep a held reference to the root vnode. 179 * It is vrele'd in ov_unmount. 180 */ 181 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 182 vp->v_vflag |= VV_ROOT; 183 nmp->ovm_rootvp = vp; 184 VOP_UNLOCK(vp); 185 186 error = set_statvfs_info(path, UIO_USERSPACE, args->la.target, 187 UIO_USERSPACE, mp->mnt_op->vfs_name, mp, l); 188 if (error) 189 return error; 190 191 if (mp->mnt_lower->mnt_flag & MNT_LOCAL) 192 mp->mnt_flag |= MNT_LOCAL; 193 #ifdef OVERLAYFS_DIAGNOSTIC 194 printf("ov_mount: lower %s, alias at %s\n", 195 mp->mnt_stat.f_mntfromname, mp->mnt_stat.f_mntonname); 196 #endif 197 return 0; 198 } 199 200 /* 201 * Free reference to overlay layer 202 */ 203 int 204 ov_unmount(struct mount *mp, int mntflags) 205 { 206 struct vnode *overlay_rootvp = MOUNTTOOVERLAYMOUNT(mp)->ovm_rootvp; 207 struct overlay_mount *omp; 208 int error; 209 int flags = 0; 210 211 #ifdef OVERLAYFS_DIAGNOSTIC 212 printf("ov_unmount(mp = %p)\n", mp); 213 #endif 214 215 if (mntflags & MNT_FORCE) 216 flags |= FORCECLOSE; 217 218 if (vrefcnt(overlay_rootvp) > 1 && (mntflags & MNT_FORCE) == 0) 219 return (EBUSY); 220 if ((error = vflush(mp, overlay_rootvp, flags)) != 0) 221 return (error); 222 223 #ifdef OVERLAYFS_DIAGNOSTIC 224 vprint("alias root of lower", overlay_rootvp); 225 #endif 226 /* 227 * Blow it away for future re-use 228 */ 229 vgone(overlay_rootvp); 230 /* 231 * Finally, throw away the overlay_mount structure 232 */ 233 omp = mp->mnt_data; 234 kmem_free(omp, sizeof(struct overlay_mount)); 235 mp->mnt_data = NULL; 236 return 0; 237 } 238 239 extern const struct vnodeopv_desc overlay_vnodeop_opv_desc; 240 241 const struct vnodeopv_desc * const ov_vnodeopv_descs[] = { 242 &overlay_vnodeop_opv_desc, 243 NULL, 244 }; 245 246 struct vfsops overlay_vfsops = { 247 .vfs_name = MOUNT_OVERLAY, 248 .vfs_min_mount_data = sizeof (struct overlay_args), 249 .vfs_mount = ov_mount, 250 .vfs_start = layerfs_start, 251 .vfs_unmount = ov_unmount, 252 .vfs_root = layerfs_root, 253 .vfs_quotactl = layerfs_quotactl, 254 .vfs_statvfs = layerfs_statvfs, 255 .vfs_sync = layerfs_sync, 256 .vfs_loadvnode = layerfs_loadvnode, 257 .vfs_vget = layerfs_vget, 258 .vfs_fhtovp = layerfs_fhtovp, 259 .vfs_vptofh = layerfs_vptofh, 260 .vfs_init = layerfs_init, 261 .vfs_done = layerfs_done, 262 .vfs_snapshot = layerfs_snapshot, 263 .vfs_extattrctl = vfs_stdextattrctl, 264 .vfs_suspendctl = layerfs_suspendctl, 265 .vfs_renamelock_enter = layerfs_renamelock_enter, 266 .vfs_renamelock_exit = layerfs_renamelock_exit, 267 .vfs_fsync = (void *)eopnotsupp, 268 .vfs_opv_descs = ov_vnodeopv_descs 269 }; 270 271 SYSCTL_SETUP(overlay_sysctl_setup, "overlay fs sysctl") 272 { 273 274 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 static int 282 overlay_modcmd(modcmd_t cmd, void *arg) 283 { 284 int error; 285 286 switch (cmd) { 287 case MODULE_CMD_INIT: 288 error = vfs_attach(&overlay_vfsops); 289 if (error != 0) 290 break; 291 break; 292 case MODULE_CMD_FINI: 293 error = vfs_detach(&overlay_vfsops); 294 if (error != 0) 295 break; 296 break; 297 default: 298 error = ENOTTY; 299 break; 300 } 301 302 return (error); 303 } 304
Indexes created Tue Sep 30 07:10:03 GMT 2025