1 /* $NetBSD: layer_vfsops.c,v 1.56 2022/12/09 10:33:18 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 1.56 2022/12/09 10:33:18 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/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, int lktype, 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, lktype | LK_RETRY); 142 *vpp = vp; 143 return 0; 144 } 145 146 int 147 layerfs_quotactl(struct mount *mp, struct quotactl_args *args) 148 { 149 int error; 150 151 error = vfs_busy(mp); 152 if (error == 0) { 153 error = VFS_QUOTACTL(mp->mnt_lower, args); 154 vfs_unbusy(mp); 155 } 156 157 return error; 158 } 159 160 int 161 layerfs_statvfs(struct mount *mp, struct statvfs *sbp) 162 { 163 struct statvfs *sbuf; 164 int error; 165 166 sbuf = kmem_zalloc(sizeof(*sbuf), KM_SLEEP); 167 error = vfs_busy(mp); 168 if (error == 0) { 169 error = VFS_STATVFS(mp->mnt_lower, sbuf); 170 vfs_unbusy(mp); 171 } 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); 218 219 /* Share the interlock, vmobjlock, and klist with the lower node. */ 220 vshareilock(vp, lowervp); 221 rw_obj_hold(lowervp->v_uobj.vmobjlock); 222 uvm_obj_setlock(&vp->v_uobj, lowervp->v_uobj.vmobjlock); 223 vshareklist(vp, lowervp); 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, int lktype, struct vnode **vpp) 244 { 245 struct vnode *vp; 246 int error; 247 248 error = vfs_busy(mp); 249 if (error == 0) { 250 error = VFS_VGET(mp->mnt_lower, ino, lktype, &vp); 251 vfs_unbusy(mp); 252 } 253 if (error) { 254 *vpp = NULL; 255 return error; 256 } 257 VOP_UNLOCK(vp); 258 error = layer_node_create(mp, vp, vpp); 259 if (error) { 260 vrele(vp); 261 *vpp = NULL; 262 return error; 263 } 264 error = vn_lock(*vpp, lktype); 265 if (error) { 266 vrele(*vpp); 267 *vpp = NULL; 268 return error; 269 } 270 return 0; 271 } 272 273 int 274 layerfs_fhtovp(struct mount *mp, struct fid *fidp, int lktype, 275 struct vnode **vpp) 276 { 277 struct vnode *vp; 278 int error; 279 280 error = vfs_busy(mp); 281 if (error == 0) { 282 error = VFS_FHTOVP(mp->mnt_lower, fidp, lktype, &vp); 283 vfs_unbusy(mp); 284 } 285 if (error) { 286 *vpp = NULL; 287 return error; 288 } 289 VOP_UNLOCK(vp); 290 error = layer_node_create(mp, vp, vpp); 291 if (error) { 292 vput(vp); 293 *vpp = NULL; 294 return (error); 295 } 296 error = vn_lock(*vpp, lktype); 297 if (error) { 298 vrele(*vpp); 299 *vpp = NULL; 300 return error; 301 } 302 return 0; 303 } 304 305 int 306 layerfs_vptofh(struct vnode *vp, struct fid *fhp, size_t *fh_size) 307 { 308 309 return VFS_VPTOFH(LAYERVPTOLOWERVP(vp), fhp, fh_size); 310 } 311 312 /* 313 * layerfs_snapshot - handle a snapshot through a layered file system 314 * 315 * At present, we do NOT support snapshotting through a layered file 316 * system as the ffs implementation changes v_vnlock of the snapshot 317 * vnodes to point to one common lock. As there is no way for us to 318 * absolutely pass this change up the stack, a layered file system 319 * would end up referencing the wrong lock. 320 * 321 * This routine serves as a central resource for this behavior; all 322 * layered file systems don't need to worry about the above. Also, if 323 * things get fixed, all layers get the benefit. 324 */ 325 int 326 layerfs_snapshot(struct mount *mp, struct vnode *vp, 327 struct timespec *ts) 328 { 329 330 return EOPNOTSUPP; 331 } 332 333 /* 334 * layerfs_suspendctl - suspend a layered file system 335 * 336 * Here we should suspend the lower file system(s) too. At present 337 * this will deadlock as we don't know which to suspend first. 338 * 339 * This routine serves as a central resource for this behavior; all 340 * layered file systems don't need to worry about the above. Also, if 341 * things get fixed, all layers get the benefit. 342 */ 343 int 344 layerfs_suspendctl(struct mount *mp, int cmd) 345 { 346 347 return genfs_suspendctl(mp, cmd); 348 } 349 350 SYSCTL_SETUP(sysctl_vfs_layerfs_setup, "sysctl vfs.layerfs subtree setup") 351 { 352 const struct sysctlnode *layerfs_node = NULL; 353 354 sysctl_createv(clog, 0, NULL, &layerfs_node, 355 #ifdef _MODULE 356 0, 357 #else 358 CTLFLAG_PERMANENT, 359 #endif 360 CTLTYPE_NODE, "layerfs", 361 SYSCTL_DESCR("Generic layered file system"), 362 NULL, 0, NULL, 0, 363 CTL_VFS, CTL_CREATE, CTL_EOL); 364 365 #ifdef LAYERFS_DIAGNOSTIC 366 sysctl_createv(clog, 0, &layerfs_node, NULL, 367 #ifndef _MODULE 368 CTLFLAG_PERMANENT | 369 #endif 370 CTLFLAG_READWRITE, 371 CTLTYPE_INT, 372 "debug", 373 SYSCTL_DESCR("Verbose debugging messages"), 374 NULL, 0, &layerfs_debug, 0, 375 CTL_CREATE, CTL_EOL); 376 #endif 377 378 /* 379 * other subtrees should really be aliases to this, but since 380 * they can't tell if layerfs has been instantiated yet, they 381 * can't do that...not easily. not yet. :-) 382 */ 383 } 384 385 int 386 layerfs_renamelock_enter(struct mount *mp) 387 { 388 389 return VFS_RENAMELOCK_ENTER(mp->mnt_lower); 390 } 391 392 void 393 layerfs_renamelock_exit(struct mount *mp) 394 { 395 396 VFS_RENAMELOCK_EXIT(mp->mnt_lower); 397 } 398
Indexes created Sun Sep 21 18:09:52 GMT 2025