overlay_vfsops.c revision 1.69
1 /* $NetBSD: overlay_vfsops.c,v 1.69 2020/03/16 21:20:11 pgoyette 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 1.69 2020/03/16 21:20:11 pgoyette 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; 152 153 /* 154 * Make sure that the mount point is sufficiently initialized 155 * that the node create call will work. 156 */ 157 vfs_getnewfsid(mp); 158 mp->mnt_lower = lowerrootvp->v_mount; 159 160 nmp->ovm_size = sizeof (struct overlay_node); 161 nmp->ovm_tag = VT_OVERLAY; 162 nmp->ovm_bypass = layer_bypass; 163 nmp->ovm_vnodeop_p = overlay_vnodeop_p; 164 165 /* 166 * Fix up overlay node for root vnode 167 */ 168 VOP_UNLOCK(lowerrootvp); 169 error = layer_node_create(mp, lowerrootvp, &vp); 170 /* 171 * Make sure the fixup worked 172 */ 173 if (error) { 174 vrele(lowerrootvp); 175 kmem_free(nmp, sizeof(struct overlay_mount)); 176 return error; 177 } 178 179 /* 180 * Keep a held reference to the root vnode. 181 * It is vrele'd in ov_unmount. 182 */ 183 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 184 vp->v_vflag |= VV_ROOT; 185 nmp->ovm_rootvp = vp; 186 VOP_UNLOCK(vp); 187 188 error = set_statvfs_info(path, UIO_USERSPACE, args->la.target, 189 UIO_USERSPACE, mp->mnt_op->vfs_name, mp, l); 190 if (error) 191 return error; 192 193 if (mp->mnt_lower->mnt_flag & MNT_LOCAL) 194 mp->mnt_flag |= MNT_LOCAL; 195 #ifdef OVERLAYFS_DIAGNOSTIC 196 printf("ov_mount: lower %s, alias at %s\n", 197 mp->mnt_stat.f_mntfromname, mp->mnt_stat.f_mntonname); 198 #endif 199 return 0; 200 } 201 202 /* 203 * Free reference to overlay layer 204 */ 205 int 206 ov_unmount(struct mount *mp, int mntflags) 207 { 208 struct vnode *overlay_rootvp = MOUNTTOOVERLAYMOUNT(mp)->ovm_rootvp; 209 struct overlay_mount *omp; 210 int error; 211 int flags = 0; 212 213 #ifdef OVERLAYFS_DIAGNOSTIC 214 printf("ov_unmount(mp = %p)\n", mp); 215 #endif 216 217 if (mntflags & MNT_FORCE) 218 flags |= FORCECLOSE; 219 220 if (overlay_rootvp->v_usecount > 1 && (mntflags & MNT_FORCE) == 0) 221 return (EBUSY); 222 if ((error = vflush(mp, overlay_rootvp, flags)) != 0) 223 return (error); 224 225 #ifdef OVERLAYFS_DIAGNOSTIC 226 vprint("alias root of lower", overlay_rootvp); 227 #endif 228 /* 229 * Blow it away for future re-use 230 */ 231 vgone(overlay_rootvp); 232 /* 233 * Finally, throw away the overlay_mount structure 234 */ 235 omp = mp->mnt_data; 236 kmem_free(omp, sizeof(struct overlay_mount)); 237 mp->mnt_data = NULL; 238 return 0; 239 } 240 241 extern const struct vnodeopv_desc overlay_vnodeop_opv_desc; 242 243 const struct vnodeopv_desc * const ov_vnodeopv_descs[] = { 244 &overlay_vnodeop_opv_desc, 245 NULL, 246 }; 247 248 struct vfsops overlay_vfsops = { 249 .vfs_name = MOUNT_OVERLAY, 250 .vfs_min_mount_data = sizeof (struct overlay_args), 251 .vfs_mount = ov_mount, 252 .vfs_start = layerfs_start, 253 .vfs_unmount = ov_unmount, 254 .vfs_root = layerfs_root, 255 .vfs_quotactl = layerfs_quotactl, 256 .vfs_statvfs = layerfs_statvfs, 257 .vfs_sync = layerfs_sync, 258 .vfs_loadvnode = layerfs_loadvnode, 259 .vfs_vget = layerfs_vget, 260 .vfs_fhtovp = layerfs_fhtovp, 261 .vfs_vptofh = layerfs_vptofh, 262 .vfs_init = layerfs_init, 263 .vfs_done = layerfs_done, 264 .vfs_snapshot = layerfs_snapshot, 265 .vfs_extattrctl = vfs_stdextattrctl, 266 .vfs_suspendctl = layerfs_suspendctl, 267 .vfs_renamelock_enter = layerfs_renamelock_enter, 268 .vfs_renamelock_exit = layerfs_renamelock_exit, 269 .vfs_fsync = (void *)eopnotsupp, 270 .vfs_opv_descs = ov_vnodeopv_descs 271 }; 272 273 SYSCTL_SETUP(overlay_sysctl_setup, "overlay fs sysctl") 274 { 275 276 sysctl_createv(&overlay_sysctl_log, 0, NULL, NULL, 277 CTLFLAG_PERMANENT, CTLTYPE_NODE, "overlay", 278 SYSCTL_DESCR("Overlay file system"), 279 NULL, 0, NULL, 0, 280 CTL_VFS, CTL_CREATE, CTL_EOL); 281 } 282 283 static int 284 overlay_modcmd(modcmd_t cmd, void *arg) 285 { 286 int error; 287 288 switch (cmd) { 289 case MODULE_CMD_INIT: 290 error = vfs_attach(&overlay_vfsops); 291 if (error != 0) 292 break; 293 break; 294 case MODULE_CMD_FINI: 295 error = vfs_detach(&overlay_vfsops); 296 if (error != 0) 297 break; 298 break; 299 default: 300 error = ENOTTY; 301 break; 302 } 303 304 return (error); 305 } 306
Indexes created Tue Sep 30 07:10:03 GMT 2025