| 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 | |