1 /* $NetBSD: layer_vfsops.c,v 1.46 2015/04/20 19:36:55 riastradh Exp $ */ 2 3 /* 4 * Copyright (c) 1999 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 /* 37 * Copyright (c) 1992, 1993, 1995 38 * The Regents of the University of California. All rights reserved. 39 * 40 * This code is derived from software donated to Berkeley by 41 * Jan-Simon Pendry. 42 * 43 * Redistribution and use in source and binary forms, with or without 44 * modification, are permitted provided that the following conditions 45 * are met: 46 * 1. Redistributions of source code must retain the above copyright 47 * notice, this list of conditions and the following disclaimer. 48 * 2. Redistributions in binary form must reproduce the above copyright 49 * notice, this list of conditions and the following disclaimer in the 50 * documentation and/or other materials provided with the distribution. 51 * 3. Neither the name of the University nor the names of its contributors 52 * may be used to endorse or promote products derived from this software 53 * without specific prior written permission. 54 * 55 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 56 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 57 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 58 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 59 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 60 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 61 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 62 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 63 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 64 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 65 * SUCH DAMAGE. 66 * 67 * from: Id: lofs_vfsops.c,v 1.9 1992/05/30 10:26:24 jsp Exp 68 * from: @(#)lofs_vfsops.c 1.2 (Berkeley) 6/18/92 69 * @(#)null_vfsops.c 8.7 (Berkeley) 5/14/95 70 */ 71 72 /* 73 * Generic layer VFS operations. 74 */ 75 76 #include <sys/cdefs.h> 77 __KERNEL_RCSID(0, "$NetBSD: layer_vfsops.c,v 1.46 2015/04/20 19:36:55 riastradh Exp $"); 78 79 #include <sys/param.h> 80 #include <sys/sysctl.h> 81 #include <sys/systm.h> 82 #include <sys/vnode.h> 83 #include <sys/mount.h> 84 #include <sys/namei.h> 85 #include <sys/kauth.h> 86 #include <sys/module.h> 87 88 #include <miscfs/specfs/specdev.h> 89 #include <miscfs/genfs/layer.h> 90 #include <miscfs/genfs/layer_extern.h> 91 92 SYSCTL_SETUP_PROTO(sysctl_vfs_layerfs_setup); 93 94 MODULE(MODULE_CLASS_MISC, layerfs, NULL); 95 96 static int 97 layerfs_modcmd(modcmd_t cmd, void *arg) 98 { 99 #ifdef _MODULE 100 static struct sysctllog *layerfs_clog = NULL; 101 #endif 102 103 switch (cmd) { 104 case MODULE_CMD_INIT: 105 #ifdef _MODULE 106 sysctl_vfs_layerfs_setup(&layerfs_clog); 107 #endif 108 return 0; 109 case MODULE_CMD_FINI: 110 #ifdef _MODULE 111 sysctl_teardown(&layerfs_clog); 112 #endif 113 return 0; 114 default: 115 return ENOTTY; 116 } 117 return 0; 118 } 119 120 /* 121 * VFS start. Nothing needed here - the start routine on the underlying 122 * filesystem will have been called when that filesystem was mounted. 123 */ 124 int 125 layerfs_start(struct mount *mp, int flags) 126 { 127 128 #ifdef notyet 129 return VFS_START(MOUNTTOLAYERMOUNT(mp)->layerm_vfs, flags); 130 #else 131 return 0; 132 #endif 133 } 134 135 int 136 layerfs_root(struct mount *mp, struct vnode **vpp) 137 { 138 struct vnode *vp; 139 140 vp = MOUNTTOLAYERMOUNT(mp)->layerm_rootvp; 141 if (vp == NULL) { 142 *vpp = NULL; 143 return EINVAL; 144 } 145 /* 146 * Return root vnode with locked and with a reference held. 147 */ 148 vref(vp); 149 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 150 *vpp = vp; 151 return 0; 152 } 153 154 int 155 layerfs_quotactl(struct mount *mp, struct quotactl_args *args) 156 { 157 158 return VFS_QUOTACTL(MOUNTTOLAYERMOUNT(mp)->layerm_vfs, args); 159 } 160 161 int 162 layerfs_statvfs(struct mount *mp, struct statvfs *sbp) 163 { 164 struct statvfs *sbuf; 165 int error; 166 167 sbuf = kmem_zalloc(sizeof(*sbuf), KM_SLEEP); 168 if (sbuf == NULL) { 169 return ENOMEM; 170 } 171 error = VFS_STATVFS(MOUNTTOLAYERMOUNT(mp)->layerm_vfs, sbuf); 172 if (error) { 173 goto done; 174 } 175 /* Copy across the relevant data and fake the rest. */ 176 sbp->f_flag = sbuf->f_flag; 177 sbp->f_bsize = sbuf->f_bsize; 178 sbp->f_frsize = sbuf->f_frsize; 179 sbp->f_iosize = sbuf->f_iosize; 180 sbp->f_blocks = sbuf->f_blocks; 181 sbp->f_bfree = sbuf->f_bfree; 182 sbp->f_bavail = sbuf->f_bavail; 183 sbp->f_bresvd = sbuf->f_bresvd; 184 sbp->f_files = sbuf->f_files; 185 sbp->f_ffree = sbuf->f_ffree; 186 sbp->f_favail = sbuf->f_favail; 187 sbp->f_fresvd = sbuf->f_fresvd; 188 sbp->f_namemax = sbuf->f_namemax; 189 copy_statvfs_info(sbp, mp); 190 done: 191 kmem_free(sbuf, sizeof(*sbuf)); 192 return error; 193 } 194 195 int 196 layerfs_sync(struct mount *mp, int waitfor, 197 kauth_cred_t cred) 198 { 199 200 /* 201 * XXX - Assumes no data cached at layer. 202 */ 203 return 0; 204 } 205 206 int 207 layerfs_loadvnode(struct mount *mp, struct vnode *vp, 208 const void *key, size_t key_len, const void **new_key) 209 { 210 struct layer_mount *lmp = MOUNTTOLAYERMOUNT(mp); 211 struct vnode *lowervp; 212 struct layer_node *xp; 213 214 KASSERT(key_len == sizeof(struct vnode *)); 215 memcpy(&lowervp, key, key_len); 216 217 xp = kmem_alloc(lmp->layerm_size, KM_SLEEP); 218 if (xp == NULL) 219 return ENOMEM; 220 221 /* Share the interlock with the lower node. */ 222 mutex_obj_hold(lowervp->v_interlock); 223 uvm_obj_setlock(&vp->v_uobj, lowervp->v_interlock); 224 225 vp->v_tag = lmp->layerm_tag; 226 vp->v_type = lowervp->v_type; 227 vp->v_op = lmp->layerm_vnodeop_p; 228 if (vp->v_type == VBLK || vp->v_type == VCHR) 229 spec_node_init(vp, lowervp->v_rdev); 230 vp->v_data = xp; 231 xp->layer_vnode = vp; 232 xp->layer_lowervp = lowervp; 233 xp->layer_flags = 0; 234 uvm_vnp_setsize(vp, 0); 235 236 /* Add a reference to the lower node. */ 237 vref(lowervp); 238 *new_key = &xp->layer_lowervp; 239 return 0; 240 } 241 242 int 243 layerfs_vget(struct mount *mp, ino_t ino, struct vnode **vpp) 244 { 245 struct vnode *vp; 246 int error; 247 248 error = VFS_VGET(MOUNTTOLAYERMOUNT(mp)->layerm_vfs, ino, &vp); 249 if (error) { 250 *vpp = NULL; 251 return error; 252 } 253 VOP_UNLOCK(vp); 254 error = layer_node_create(mp, vp, vpp); 255 if (error) { 256 vrele(vp); 257 *vpp = NULL; 258 return error; 259 } 260 error = vn_lock(*vpp, LK_EXCLUSIVE); 261 if (error) { 262 vrele(*vpp); 263 *vpp = NULL; 264 return error; 265 } 266 return 0; 267 } 268 269 int 270 layerfs_fhtovp(struct mount *mp, struct fid *fidp, struct vnode **vpp) 271 { 272 struct vnode *vp; 273 int error; 274 275 error = VFS_FHTOVP(MOUNTTOLAYERMOUNT(mp)->layerm_vfs, fidp, &vp); 276 if (error) { 277 *vpp = NULL; 278 return error; 279 } 280 VOP_UNLOCK(vp); 281 error = layer_node_create(mp, vp, vpp); 282 if (error) { 283 vput(vp); 284 *vpp = NULL; 285 return (error); 286 } 287 error = vn_lock(*vpp, LK_EXCLUSIVE); 288 if (error) { 289 vrele(*vpp); 290 *vpp = NULL; 291 return error; 292 } 293 return 0; 294 } 295 296 int 297 layerfs_vptofh(struct vnode *vp, struct fid *fhp, size_t *fh_size) 298 { 299 300 return VFS_VPTOFH(LAYERVPTOLOWERVP(vp), fhp, fh_size); 301 } 302 303 /* 304 * layerfs_snapshot - handle a snapshot through a layered file system 305 * 306 * At present, we do NOT support snapshotting through a layered file 307 * system as the ffs implementation changes v_vnlock of the snapshot 308 * vnodes to point to one common lock. As there is no way for us to 309 * absolutely pass this change up the stack, a layered file system 310 * would end up referencing the wrong lock. 311 * 312 * This routine serves as a central resource for this behavior; all 313 * layered file systems don't need to worry about the above. Also, if 314 * things get fixed, all layers get the benefit. 315 */ 316 int 317 layerfs_snapshot(struct mount *mp, struct vnode *vp, 318 struct timespec *ts) 319 { 320 321 return EOPNOTSUPP; 322 } 323 324 SYSCTL_SETUP(sysctl_vfs_layerfs_setup, "sysctl vfs.layerfs subtree setup") 325 { 326 const struct sysctlnode *layerfs_node = NULL; 327 328 sysctl_createv(clog, 0, NULL, &layerfs_node, 329 #ifdef _MODULE 330 0, 331 #else 332 CTLFLAG_PERMANENT, 333 #endif 334 CTLTYPE_NODE, "layerfs", 335 SYSCTL_DESCR("Generic layered file system"), 336 NULL, 0, NULL, 0, 337 CTL_VFS, CTL_CREATE, CTL_EOL); 338 339 #ifdef LAYERFS_DIAGNOSTIC 340 sysctl_createv(clog, 0, &layerfs_node, NULL, 341 #ifndef _MODULE 342 CTLFLAG_PERMANENT | 343 #endif 344 CTLFLAG_READWRITE, 345 CTLTYPE_INT, 346 "debug", 347 SYSCTL_DESCR("Verbose debugging messages"), 348 NULL, 0, &layerfs_debug, 0, 349 CTL_CREATE, CTL_EOL); 350 #endif 351 352 /* 353 * other subtrees should really be aliases to this, but since 354 * they can't tell if layerfs has been instantiated yet, they 355 * can't do that...not easily. not yet. :-) 356 */ 357 } 358 359 int 360 layerfs_renamelock_enter(struct mount *mp) 361 { 362 363 return VFS_RENAMELOCK_ENTER(MOUNTTOLAYERMOUNT(mp)->layerm_vfs); 364 } 365 366 void 367 layerfs_renamelock_exit(struct mount *mp) 368 { 369 370 VFS_RENAMELOCK_EXIT(MOUNTTOLAYERMOUNT(mp)->layerm_vfs); 371 } 372