1 /* $NetBSD: layer_vfsops.c,v 1.52 2019/08/07 00:38:02 pgoyette 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 1.52 2019/08/07 00:38:02 pgoyette 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/genfs.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 { 100 101 switch (cmd) { 102 case MODULE_CMD_INIT: 103 return 0; 104 case MODULE_CMD_FINI: 105 return 0; 106 default: 107 return ENOTTY; 108 } 109 return 0; 110 } 111 112 /* 113 * VFS start. Nothing needed here - the start routine on the underlying 114 * filesystem will have been called when that filesystem was mounted. 115 */ 116 int 117 layerfs_start(struct mount *mp, int flags) 118 { 119 120 #ifdef notyet 121 return VFS_START(mp->mnt_lower, flags); 122 #else 123 return 0; 124 #endif 125 } 126 127 int 128 layerfs_root(struct mount *mp, struct vnode **vpp) 129 { 130 struct vnode *vp; 131 132 vp = MOUNTTOLAYERMOUNT(mp)->layerm_rootvp; 133 if (vp == NULL) { 134 *vpp = NULL; 135 return EINVAL; 136 } 137 /* 138 * Return root vnode with locked and with a reference held. 139 */ 140 vref(vp); 141 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 142 *vpp = vp; 143 return 0; 144 } 145 146 int 147 layerfs_quotactl(struct mount *mp, struct quotactl_args *args) 148 { 149 150 return VFS_QUOTACTL(mp->mnt_lower, args); 151 } 152 153 int 154 layerfs_statvfs(struct mount *mp, struct statvfs *sbp) 155 { 156 struct statvfs *sbuf; 157 int error; 158 159 sbuf = kmem_zalloc(sizeof(*sbuf), KM_SLEEP); 160 error = VFS_STATVFS(mp->mnt_lower, sbuf); 161 if (error) { 162 goto done; 163 } 164 /* Copy across the relevant data and fake the rest. */ 165 sbp->f_flag = sbuf->f_flag; 166 sbp->f_bsize = sbuf->f_bsize; 167 sbp->f_frsize = sbuf->f_frsize; 168 sbp->f_iosize = sbuf->f_iosize; 169 sbp->f_blocks = sbuf->f_blocks; 170 sbp->f_bfree = sbuf->f_bfree; 171 sbp->f_bavail = sbuf->f_bavail; 172 sbp->f_bresvd = sbuf->f_bresvd; 173 sbp->f_files = sbuf->f_files; 174 sbp->f_ffree = sbuf->f_ffree; 175 sbp->f_favail = sbuf->f_favail; 176 sbp->f_fresvd = sbuf->f_fresvd; 177 sbp->f_namemax = sbuf->f_namemax; 178 copy_statvfs_info(sbp, mp); 179 done: 180 kmem_free(sbuf, sizeof(*sbuf)); 181 return error; 182 } 183 184 int 185 layerfs_sync(struct mount *mp, int waitfor, 186 kauth_cred_t cred) 187 { 188 189 /* 190 * XXX - Assumes no data cached at layer. 191 */ 192 return 0; 193 } 194 195 int 196 layerfs_loadvnode(struct mount *mp, struct vnode *vp, 197 const void *key, size_t key_len, const void **new_key) 198 { 199 struct layer_mount *lmp = MOUNTTOLAYERMOUNT(mp); 200 struct vnode *lowervp; 201 struct layer_node *xp; 202 203 KASSERT(key_len == sizeof(struct vnode *)); 204 memcpy(&lowervp, key, key_len); 205 206 xp = kmem_alloc(lmp->layerm_size, KM_SLEEP); 207 208 /* Share the interlock with the lower node. */ 209 mutex_obj_hold(lowervp->v_interlock); 210 uvm_obj_setlock(&vp->v_uobj, lowervp->v_interlock); 211 212 vp->v_tag = lmp->layerm_tag; 213 vp->v_type = lowervp->v_type; 214 vp->v_op = lmp->layerm_vnodeop_p; 215 if (vp->v_type == VBLK || vp->v_type == VCHR) 216 spec_node_init(vp, lowervp->v_rdev); 217 vp->v_data = xp; 218 xp->layer_vnode = vp; 219 xp->layer_lowervp = lowervp; 220 xp->layer_flags = 0; 221 uvm_vnp_setsize(vp, 0); 222 223 /* Add a reference to the lower node. */ 224 vref(lowervp); 225 *new_key = &xp->layer_lowervp; 226 return 0; 227 } 228 229 int 230 layerfs_vget(struct mount *mp, ino_t ino, struct vnode **vpp) 231 { 232 struct vnode *vp; 233 int error; 234 235 error = VFS_VGET(mp->mnt_lower, ino, &vp); 236 if (error) { 237 *vpp = NULL; 238 return error; 239 } 240 VOP_UNLOCK(vp); 241 error = layer_node_create(mp, vp, vpp); 242 if (error) { 243 vrele(vp); 244 *vpp = NULL; 245 return error; 246 } 247 error = vn_lock(*vpp, LK_EXCLUSIVE); 248 if (error) { 249 vrele(*vpp); 250 *vpp = NULL; 251 return error; 252 } 253 return 0; 254 } 255 256 int 257 layerfs_fhtovp(struct mount *mp, struct fid *fidp, struct vnode **vpp) 258 { 259 struct vnode *vp; 260 int error; 261 262 error = VFS_FHTOVP(mp->mnt_lower, fidp, &vp); 263 if (error) { 264 *vpp = NULL; 265 return error; 266 } 267 VOP_UNLOCK(vp); 268 error = layer_node_create(mp, vp, vpp); 269 if (error) { 270 vput(vp); 271 *vpp = NULL; 272 return (error); 273 } 274 error = vn_lock(*vpp, LK_EXCLUSIVE); 275 if (error) { 276 vrele(*vpp); 277 *vpp = NULL; 278 return error; 279 } 280 return 0; 281 } 282 283 int 284 layerfs_vptofh(struct vnode *vp, struct fid *fhp, size_t *fh_size) 285 { 286 287 return VFS_VPTOFH(LAYERVPTOLOWERVP(vp), fhp, fh_size); 288 } 289 290 /* 291 * layerfs_snapshot - handle a snapshot through a layered file system 292 * 293 * At present, we do NOT support snapshotting through a layered file 294 * system as the ffs implementation changes v_vnlock of the snapshot 295 * vnodes to point to one common lock. As there is no way for us to 296 * absolutely pass this change up the stack, a layered file system 297 * would end up referencing the wrong lock. 298 * 299 * This routine serves as a central resource for this behavior; all 300 * layered file systems don't need to worry about the above. Also, if 301 * things get fixed, all layers get the benefit. 302 */ 303 int 304 layerfs_snapshot(struct mount *mp, struct vnode *vp, 305 struct timespec *ts) 306 { 307 308 return EOPNOTSUPP; 309 } 310 311 /* 312 * layerfs_suspendctl - suspend a layered file system 313 * 314 * Here we should suspend the lower file system(s) too. At present 315 * this will deadlock as we don't know which to suspend first. 316 * 317 * This routine serves as a central resource for this behavior; all 318 * layered file systems don't need to worry about the above. Also, if 319 * things get fixed, all layers get the benefit. 320 */ 321 int 322 layerfs_suspendctl(struct mount *mp, int cmd) 323 { 324 325 return genfs_suspendctl(mp, cmd); 326 } 327 328 SYSCTL_SETUP(sysctl_vfs_layerfs_setup, "sysctl vfs.layerfs subtree setup") 329 { 330 const struct sysctlnode *layerfs_node = NULL; 331 332 sysctl_createv(clog, 0, NULL, &layerfs_node, 333 #ifdef _MODULE 334 0, 335 #else 336 CTLFLAG_PERMANENT, 337 #endif 338 CTLTYPE_NODE, "layerfs", 339 SYSCTL_DESCR("Generic layered file system"), 340 NULL, 0, NULL, 0, 341 CTL_VFS, CTL_CREATE, CTL_EOL); 342 343 #ifdef LAYERFS_DIAGNOSTIC 344 sysctl_createv(clog, 0, &layerfs_node, NULL, 345 #ifndef _MODULE 346 CTLFLAG_PERMANENT | 347 #endif 348 CTLFLAG_READWRITE, 349 CTLTYPE_INT, 350 "debug", 351 SYSCTL_DESCR("Verbose debugging messages"), 352 NULL, 0, &layerfs_debug, 0, 353 CTL_CREATE, CTL_EOL); 354 #endif 355 356 /* 357 * other subtrees should really be aliases to this, but since 358 * they can't tell if layerfs has been instantiated yet, they 359 * can't do that...not easily. not yet. :-) 360 */ 361 } 362 363 int 364 layerfs_renamelock_enter(struct mount *mp) 365 { 366 367 return VFS_RENAMELOCK_ENTER(mp->mnt_lower); 368 } 369 370 void 371 layerfs_renamelock_exit(struct mount *mp) 372 { 373 374 VFS_RENAMELOCK_EXIT(mp->mnt_lower); 375 } 376