1 /* $NetBSD: overlay_vfsops.c,v 1.74 2025/02/16 18:38:58 joe 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 1.74 2025/02/16 18:38:58 joe 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))) { 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 error = vfs_set_lowermount(mp, lowerrootvp->v_mount); 157 if (error) { 158 vput(lowerrootvp); 159 kmem_free(nmp, sizeof(struct overlay_mount)); 160 return error; 161 } 162 163 nmp->ovm_size = sizeof (struct overlay_node); 164 nmp->ovm_tag = VT_OVERLAY; 165 nmp->ovm_bypass = layer_bypass; 166 nmp->ovm_vnodeop_p = overlay_vnodeop_p; 167 168 /* 169 * Fix up overlay node for root vnode 170 */ 171 VOP_UNLOCK(lowerrootvp); 172 error = layer_node_create(mp, lowerrootvp, &vp); 173 /* 174 * Make sure the fixup worked 175 */ 176 if (error) { 177 vrele(lowerrootvp); 178 kmem_free(nmp, sizeof(struct overlay_mount)); 179 return error; 180 } 181 182 /* 183 * Keep a held reference to the root vnode. 184 * It is vrele'd in ov_unmount. 185 */ 186 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 187 vp->v_vflag |= VV_ROOT; 188 nmp->ovm_rootvp = vp; 189 VOP_UNLOCK(vp); 190 191 error = set_statvfs_info(path, UIO_USERSPACE, args->la.target, 192 UIO_USERSPACE, mp->mnt_op->vfs_name, mp, l); 193 if (error) 194 return error; 195 196 if (mp->mnt_lower->mnt_flag & MNT_LOCAL) 197 mp->mnt_flag |= MNT_LOCAL; 198 #ifdef OVERLAYFS_DIAGNOSTIC 199 printf("ov_mount: lower %s, alias at %s\n", 200 mp->mnt_stat.f_mntfromname, mp->mnt_stat.f_mntonname); 201 #endif 202 return 0; 203 } 204 205 /* 206 * Free reference to overlay layer 207 */ 208 int 209 ov_unmount(struct mount *mp, int mntflags) 210 { 211 struct vnode *overlay_rootvp = MOUNTTOOVERLAYMOUNT(mp)->ovm_rootvp; 212 struct overlay_mount *omp; 213 int error; 214 int flags = 0; 215 216 #ifdef OVERLAYFS_DIAGNOSTIC 217 printf("ov_unmount(mp = %p)\n", mp); 218 #endif 219 220 if (mntflags & MNT_FORCE) 221 flags |= FORCECLOSE; 222 223 if (vrefcnt(overlay_rootvp) > 1 && (mntflags & MNT_FORCE) == 0) 224 return (EBUSY); 225 if ((error = vflush(mp, overlay_rootvp, flags)) != 0) 226 return (error); 227 228 #ifdef OVERLAYFS_DIAGNOSTIC 229 vprint("alias root of lower", overlay_rootvp); 230 #endif 231 /* 232 * Blow it away for future re-use 233 */ 234 vgone(overlay_rootvp); 235 /* 236 * Finally, throw away the overlay_mount structure 237 */ 238 omp = mp->mnt_data; 239 kmem_free(omp, sizeof(struct overlay_mount)); 240 mp->mnt_data = NULL; 241 return 0; 242 } 243 244 extern const struct vnodeopv_desc overlay_vnodeop_opv_desc; 245 246 const struct vnodeopv_desc * const ov_vnodeopv_descs[] = { 247 &overlay_vnodeop_opv_desc, 248 NULL, 249 }; 250 251 struct vfsops overlay_vfsops = { 252 .vfs_name = MOUNT_OVERLAY, 253 .vfs_min_mount_data = sizeof (struct overlay_args), 254 .vfs_mount = ov_mount, 255 .vfs_start = layerfs_start, 256 .vfs_unmount = ov_unmount, 257 .vfs_root = layerfs_root, 258 .vfs_quotactl = layerfs_quotactl, 259 .vfs_statvfs = layerfs_statvfs, 260 .vfs_sync = layerfs_sync, 261 .vfs_loadvnode = layerfs_loadvnode, 262 .vfs_vget = layerfs_vget, 263 .vfs_fhtovp = layerfs_fhtovp, 264 .vfs_vptofh = layerfs_vptofh, 265 .vfs_init = layerfs_init, 266 .vfs_done = layerfs_done, 267 .vfs_snapshot = layerfs_snapshot, 268 .vfs_extattrctl = vfs_stdextattrctl, 269 .vfs_suspendctl = layerfs_suspendctl, 270 .vfs_renamelock_enter = layerfs_renamelock_enter, 271 .vfs_renamelock_exit = layerfs_renamelock_exit, 272 .vfs_fsync = (void *)eopnotsupp, 273 .vfs_opv_descs = ov_vnodeopv_descs 274 }; 275 276 SYSCTL_SETUP(overlay_sysctl_setup, "overlay fs sysctl") 277 { 278 279 sysctl_createv(clog, 0, NULL, NULL, 280 CTLFLAG_PERMANENT, CTLTYPE_NODE, "overlay", 281 SYSCTL_DESCR("Overlay file system"), 282 NULL, 0, NULL, 0, 283 CTL_VFS, CTL_CREATE, CTL_EOL); 284 } 285 286 static int 287 overlay_modcmd(modcmd_t cmd, void *arg) 288 { 289 int error; 290 291 switch (cmd) { 292 case MODULE_CMD_INIT: 293 error = vfs_attach(&overlay_vfsops); 294 break; 295 case MODULE_CMD_FINI: 296 error = vfs_detach(&overlay_vfsops); 297 break; 298 default: 299 error = ENOTTY; 300 break; 301 } 302 303 return (error); 304 } 305
Indexes created Mon Sep 29 21:09:56 GMT 2025