1 /* $NetBSD: layer_vfsops.c,v 1.44 2014/05/25 13:51:25 hannken 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 1.44 2014/05/25 13:51:25 hannken 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/malloc.h> 86 #include <sys/kauth.h> 87 #include <sys/module.h> 88 89 #include <miscfs/specfs/specdev.h> 90 #include <miscfs/genfs/layer.h> 91 #include <miscfs/genfs/layer_extern.h> 92 93 SYSCTL_SETUP_PROTO(sysctl_vfs_layerfs_setup); 94 95 MODULE(MODULE_CLASS_MISC, layerfs, NULL); 96 97 static int 98 layerfs_modcmd(modcmd_t cmd, void *arg) 99 { 100 #ifdef _MODULE 101 static struct sysctllog *layerfs_clog = NULL; 102 #endif 103 104 switch (cmd) { 105 case MODULE_CMD_INIT: 106 #ifdef _MODULE 107 sysctl_vfs_layerfs_setup(&layerfs_clog); 108 #endif 109 return 0; 110 case MODULE_CMD_FINI: 111 #ifdef _MODULE 112 sysctl_teardown(&layerfs_clog); 113 #endif 114 return 0; 115 default: 116 return ENOTTY; 117 } 118 return 0; 119 } 120 121 /* 122 * VFS start. Nothing needed here - the start routine on the underlying 123 * filesystem will have been called when that filesystem was mounted. 124 */ 125 int 126 layerfs_start(struct mount *mp, int flags) 127 { 128 129 #ifdef notyet 130 return VFS_START(MOUNTTOLAYERMOUNT(mp)->layerm_vfs, flags); 131 #else 132 return 0; 133 #endif 134 } 135 136 int 137 layerfs_root(struct mount *mp, struct vnode **vpp) 138 { 139 struct vnode *vp; 140 141 vp = MOUNTTOLAYERMOUNT(mp)->layerm_rootvp; 142 if (vp == NULL) { 143 *vpp = NULL; 144 return EINVAL; 145 } 146 /* 147 * Return root vnode with locked and with a reference held. 148 */ 149 vref(vp); 150 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 151 *vpp = vp; 152 return 0; 153 } 154 155 int 156 layerfs_quotactl(struct mount *mp, struct quotactl_args *args) 157 { 158 159 return VFS_QUOTACTL(MOUNTTOLAYERMOUNT(mp)->layerm_vfs, args); 160 } 161 162 int 163 layerfs_statvfs(struct mount *mp, struct statvfs *sbp) 164 { 165 struct statvfs *sbuf; 166 int error; 167 168 sbuf = kmem_zalloc(sizeof(*sbuf), KM_SLEEP); 169 if (sbuf == NULL) { 170 return ENOMEM; 171 } 172 error = VFS_STATVFS(MOUNTTOLAYERMOUNT(mp)->layerm_vfs, sbuf); 173 if (error) { 174 goto done; 175 } 176 /* Copy across the relevant data and fake the rest. */ 177 sbp->f_flag = sbuf->f_flag; 178 sbp->f_bsize = sbuf->f_bsize; 179 sbp->f_frsize = sbuf->f_frsize; 180 sbp->f_iosize = sbuf->f_iosize; 181 sbp->f_blocks = sbuf->f_blocks; 182 sbp->f_bfree = sbuf->f_bfree; 183 sbp->f_bavail = sbuf->f_bavail; 184 sbp->f_bresvd = sbuf->f_bresvd; 185 sbp->f_files = sbuf->f_files; 186 sbp->f_ffree = sbuf->f_ffree; 187 sbp->f_favail = sbuf->f_favail; 188 sbp->f_fresvd = sbuf->f_fresvd; 189 sbp->f_namemax = sbuf->f_namemax; 190 copy_statvfs_info(sbp, mp); 191 done: 192 kmem_free(sbuf, sizeof(*sbuf)); 193 return error; 194 } 195 196 int 197 layerfs_sync(struct mount *mp, int waitfor, 198 kauth_cred_t cred) 199 { 200 201 /* 202 * XXX - Assumes no data cached at layer. 203 */ 204 return 0; 205 } 206 207 int 208 layerfs_loadvnode(struct mount *mp, struct vnode *vp, 209 const void *key, size_t key_len, const void **new_key) 210 { 211 struct layer_mount *lmp = MOUNTTOLAYERMOUNT(mp); 212 struct vnode *lowervp; 213 struct layer_node *xp; 214 215 KASSERT(key_len == sizeof(struct vnode *)); 216 memcpy(&lowervp, key, key_len); 217 218 xp = kmem_alloc(lmp->layerm_size, KM_SLEEP); 219 if (xp == NULL) 220 return ENOMEM; 221 222 /* Share the interlock with the lower node. */ 223 mutex_obj_hold(lowervp->v_interlock); 224 uvm_obj_setlock(&vp->v_uobj, lowervp->v_interlock); 225 vp->v_iflag |= VI_LAYER | VI_LOCKSHARE; 226 227 vp->v_tag = lmp->layerm_tag; 228 vp->v_type = lowervp->v_type; 229 vp->v_op = lmp->layerm_vnodeop_p; 230 if (vp->v_type == VBLK || vp->v_type == VCHR) 231 spec_node_init(vp, lowervp->v_rdev); 232 vp->v_data = xp; 233 xp->layer_vnode = vp; 234 xp->layer_lowervp = lowervp; 235 xp->layer_flags = 0; 236 uvm_vnp_setsize(vp, 0); 237 238 /* Add a reference to the lower node. */ 239 vref(lowervp); 240 *new_key = &xp->layer_lowervp; 241 return 0; 242 } 243 244 int 245 layerfs_vget(struct mount *mp, ino_t ino, struct vnode **vpp) 246 { 247 struct vnode *vp; 248 int error; 249 250 error = VFS_VGET(MOUNTTOLAYERMOUNT(mp)->layerm_vfs, ino, &vp); 251 if (error) { 252 *vpp = NULL; 253 return error; 254 } 255 VOP_UNLOCK(vp); 256 error = layer_node_create(mp, vp, vpp); 257 if (error) { 258 vrele(vp); 259 *vpp = NULL; 260 return error; 261 } 262 error = vn_lock(*vpp, LK_EXCLUSIVE); 263 if (error) { 264 vrele(*vpp); 265 *vpp = NULL; 266 return error; 267 } 268 return 0; 269 } 270 271 int 272 layerfs_fhtovp(struct mount *mp, struct fid *fidp, struct vnode **vpp) 273 { 274 struct vnode *vp; 275 int error; 276 277 error = VFS_FHTOVP(MOUNTTOLAYERMOUNT(mp)->layerm_vfs, fidp, &vp); 278 if (error) { 279 *vpp = NULL; 280 return error; 281 } 282 VOP_UNLOCK(vp); 283 error = layer_node_create(mp, vp, vpp); 284 if (error) { 285 vput(vp); 286 *vpp = NULL; 287 return (error); 288 } 289 error = vn_lock(*vpp, LK_EXCLUSIVE); 290 if (error) { 291 vrele(*vpp); 292 *vpp = NULL; 293 return error; 294 } 295 return 0; 296 } 297 298 int 299 layerfs_vptofh(struct vnode *vp, struct fid *fhp, size_t *fh_size) 300 { 301 302 return VFS_VPTOFH(LAYERVPTOLOWERVP(vp), fhp, fh_size); 303 } 304 305 /* 306 * layerfs_snapshot - handle a snapshot through a layered file system 307 * 308 * At present, we do NOT support snapshotting through a layered file 309 * system as the ffs implementation changes v_vnlock of the snapshot 310 * vnodes to point to one common lock. As there is no way for us to 311 * absolutely pass this change up the stack, a layered file system 312 * would end up referencing the wrong lock. 313 * 314 * This routine serves as a central resource for this behavior; all 315 * layered file systems don't need to worry about the above. Also, if 316 * things get fixed, all layers get the benefit. 317 */ 318 int 319 layerfs_snapshot(struct mount *mp, struct vnode *vp, 320 struct timespec *ts) 321 { 322 323 return EOPNOTSUPP; 324 } 325 326 SYSCTL_SETUP(sysctl_vfs_layerfs_setup, "sysctl vfs.layerfs subtree setup") 327 { 328 const struct sysctlnode *layerfs_node = NULL; 329 330 sysctl_createv(clog, 0, NULL, &layerfs_node, 331 #ifdef _MODULE 332 0, 333 #else 334 CTLFLAG_PERMANENT, 335 #endif 336 CTLTYPE_NODE, "layerfs", 337 SYSCTL_DESCR("Generic layered file system"), 338 NULL, 0, NULL, 0, 339 CTL_VFS, CTL_CREATE, CTL_EOL); 340 341 #ifdef LAYERFS_DIAGNOSTIC 342 sysctl_createv(clog, 0, &layerfs_node, NULL, 343 #ifndef _MODULE 344 CTLFLAG_PERMANENT | 345 #endif 346 CTLFLAG_READWRITE, 347 CTLTYPE_INT, 348 "debug", 349 SYSCTL_DESCR("Verbose debugging messages"), 350 NULL, 0, &layerfs_debug, 0, 351 CTL_CREATE, CTL_EOL); 352 #endif 353 354 /* 355 * other subtrees should really be aliases to this, but since 356 * they can't tell if layerfs has been instantiated yet, they 357 * can't do that...not easily. not yet. :-) 358 */ 359 } 360 361 int 362 layerfs_renamelock_enter(struct mount *mp) 363 { 364 365 return VFS_RENAMELOCK_ENTER(MOUNTTOLAYERMOUNT(mp)->layerm_vfs); 366 } 367 368 void 369 layerfs_renamelock_exit(struct mount *mp) 370 { 371 372 VFS_RENAMELOCK_EXIT(MOUNTTOLAYERMOUNT(mp)->layerm_vfs); 373 } 374