overlay_vfsops.c revision 1.60
1 /* $NetBSD: overlay_vfsops.c,v 1.60 2014/03/23 15:21:16 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 1.60 2014/03/23 15:21:16 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/malloc.h> 88 #include <sys/module.h> 89 #include <miscfs/overlay/overlay.h> 90 #include <miscfs/genfs/layer_extern.h> 91 92 MODULE(MODULE_CLASS_VFS, overlay, "layerfs"); 93 94 VFS_PROTOS(ov); 95 96 static struct sysctllog *overlay_sysctl_log; 97 98 #define NOVERLAYNODECACHE 16 99 100 /* 101 * Mount overlay layer 102 */ 103 int 104 ov_mount(struct mount *mp, const char *path, void *data, size_t *data_len) 105 { 106 struct lwp *l = curlwp; 107 int error = 0; 108 struct overlay_args *args = data; 109 struct vnode *lowerrootvp, *vp; 110 struct overlay_mount *nmp; 111 struct layer_mount *lmp; 112 113 #ifdef OVERLAYFS_DIAGNOSTIC 114 printf("ov_mount(mp = %p)\n", mp); 115 #endif 116 117 if (*data_len < sizeof *args) 118 return EINVAL; 119 120 if (mp->mnt_flag & MNT_GETARGS) { 121 lmp = MOUNTTOLAYERMOUNT(mp); 122 if (lmp == NULL) 123 return EIO; 124 args->la.target = NULL; 125 *data_len = sizeof *args; 126 return 0; 127 } 128 129 /* 130 * Update is not supported 131 */ 132 if (mp->mnt_flag & MNT_UPDATE) 133 return EOPNOTSUPP; 134 135 /* 136 * Find lower node 137 */ 138 lowerrootvp = mp->mnt_vnodecovered; 139 vref(lowerrootvp); 140 if ((error = vn_lock(lowerrootvp, LK_EXCLUSIVE | LK_RETRY))) { 141 vrele(lowerrootvp); 142 return (error); 143 } 144 145 /* 146 * First cut at fixing up upper mount point 147 */ 148 nmp = kmem_zalloc(sizeof(struct overlay_mount), KM_SLEEP); 149 150 mp->mnt_data = nmp; 151 nmp->ovm_vfs = lowerrootvp->v_mount; 152 if (nmp->ovm_vfs->mnt_flag & MNT_LOCAL) 153 mp->mnt_flag |= MNT_LOCAL; 154 155 /* 156 * Make sure that the mount point is sufficiently initialized 157 * that the node create call will work. 158 */ 159 vfs_getnewfsid(mp); 160 161 nmp->ovm_size = sizeof (struct overlay_node); 162 nmp->ovm_tag = VT_OVERLAY; 163 nmp->ovm_bypass = layer_bypass; 164 nmp->ovm_alloc = layer_node_alloc; /* the default alloc is fine */ 165 nmp->ovm_vnodeop_p = overlay_vnodeop_p; 166 mutex_init(&nmp->ovm_hashlock, MUTEX_DEFAULT, IPL_NONE); 167 nmp->ovm_node_hashtbl = hashinit(NOVERLAYNODECACHE, HASH_LIST, true, 168 &nmp->ovm_node_hash); 169 170 /* 171 * Fix up overlay node for root vnode 172 */ 173 VOP_UNLOCK(lowerrootvp); 174 error = layer_node_create(mp, lowerrootvp, &vp); 175 /* 176 * Make sure the fixup worked 177 */ 178 if (error) { 179 vrele(lowerrootvp); 180 hashdone(nmp->ovm_node_hashtbl, HASH_LIST, nmp->ovm_node_hash); 181 kmem_free(nmp, sizeof(struct overlay_mount)); 182 return error; 183 } 184 185 /* 186 * Keep a held reference to the root vnode. 187 * It is vrele'd in ov_unmount. 188 */ 189 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 190 vp->v_vflag |= VV_ROOT; 191 nmp->ovm_rootvp = vp; 192 VOP_UNLOCK(vp); 193 194 error = set_statvfs_info(path, UIO_USERSPACE, args->la.target, 195 UIO_USERSPACE, mp->mnt_op->vfs_name, mp, l); 196 #ifdef OVERLAYFS_DIAGNOSTIC 197 printf("ov_mount: lower %s, alias at %s\n", 198 mp->mnt_stat.f_mntfromname, mp->mnt_stat.f_mntonname); 199 #endif 200 return error; 201 } 202 203 /* 204 * Free reference to overlay layer 205 */ 206 int 207 ov_unmount(struct mount *mp, int mntflags) 208 { 209 struct vnode *overlay_rootvp = MOUNTTOOVERLAYMOUNT(mp)->ovm_rootvp; 210 struct overlay_mount *omp; 211 int error; 212 int flags = 0; 213 214 #ifdef OVERLAYFS_DIAGNOSTIC 215 printf("ov_unmount(mp = %p)\n", mp); 216 #endif 217 218 if (mntflags & MNT_FORCE) 219 flags |= FORCECLOSE; 220 221 if (overlay_rootvp->v_usecount > 1 && (mntflags & MNT_FORCE) == 0) 222 return (EBUSY); 223 if ((error = vflush(mp, overlay_rootvp, flags)) != 0) 224 return (error); 225 226 #ifdef OVERLAYFS_DIAGNOSTIC 227 vprint("alias root of lower", overlay_rootvp); 228 #endif 229 /* 230 * Blow it away for future re-use 231 */ 232 vgone(overlay_rootvp); 233 /* 234 * Finally, throw away the overlay_mount structure 235 */ 236 omp = mp->mnt_data; 237 mutex_destroy(&omp->ovm_hashlock); 238 hashdone(omp->ovm_node_hashtbl, HASH_LIST, omp->ovm_node_hash); 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_vget = layerfs_vget, 262 .vfs_fhtovp = layerfs_fhtovp, 263 .vfs_vptofh = layerfs_vptofh, 264 .vfs_init = layerfs_init, 265 .vfs_done = layerfs_done, 266 .vfs_snapshot = layerfs_snapshot, 267 .vfs_extattrctl = vfs_stdextattrctl, 268 .vfs_suspendctl = (void *)eopnotsupp, 269 .vfs_renamelock_enter = layerfs_renamelock_enter, 270 .vfs_renamelock_exit = layerfs_renamelock_exit, 271 .vfs_fsync = (void *)eopnotsupp, 272 .vfs_opv_descs = ov_vnodeopv_descs 273 }; 274 275 static int 276 overlay_modcmd(modcmd_t cmd, void *arg) 277 { 278 int error; 279 280 switch (cmd) { 281 case MODULE_CMD_INIT: 282 error = vfs_attach(&overlay_vfsops); 283 if (error != 0) 284 break; 285 sysctl_createv(&overlay_sysctl_log, 0, NULL, NULL, 286 CTLFLAG_PERMANENT, CTLTYPE_NODE, "overlay", 287 SYSCTL_DESCR("Overlay file system"), 288 NULL, 0, NULL, 0, 289 CTL_VFS, CTL_CREATE, CTL_EOL); 290 break; 291 case MODULE_CMD_FINI: 292 error = vfs_detach(&overlay_vfsops); 293 if (error != 0) 294 break; 295 sysctl_teardown(&overlay_sysctl_log); 296 break; 297 default: 298 error = ENOTTY; 299 break; 300 } 301 302 return (error); 303 } 304
Indexes created Mon Sep 29 21:09:56 GMT 2025