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1.1 ! root 1: /* ! 2: * Copyright (c) 1999 Apple Computer, Inc. All rights reserved. ! 3: * ! 4: * @APPLE_LICENSE_HEADER_START@ ! 5: * ! 6: * Portions Copyright (c) 1999 Apple Computer, Inc. All Rights ! 7: * Reserved. This file contains Original Code and/or Modifications of ! 8: * Original Code as defined in and that are subject to the Apple Public ! 9: * Source License Version 1.1 (the "License"). You may not use this file ! 10: * except in compliance with the License. Please obtain a copy of the ! 11: * License at http://www.apple.com/publicsource and read it before using ! 12: * this file. ! 13: * ! 14: * The Original Code and all software distributed under the License are ! 15: * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER ! 16: * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, ! 17: * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, ! 18: * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT. Please see the ! 19: * License for the specific language governing rights and limitations ! 20: * under the License. ! 21: * ! 22: * @APPLE_LICENSE_HEADER_END@ ! 23: */ ! 24: ! 25: /* Copyright (c) 1995 NeXT Computer, Inc. All Rights Reserved */ ! 26: /* ! 27: * Copyright (c) 1992, 1993 ! 28: * The Regents of the University of California. All rights reserved. ! 29: * ! 30: * This code is derived from software contributed to Berkeley by ! 31: * John Heidemann of the UCLA Ficus project. ! 32: * ! 33: * Redistribution and use in source and binary forms, with or without ! 34: * modification, are permitted provided that the following conditions ! 35: * are met: ! 36: * 1. Redistributions of source code must retain the above copyright ! 37: * notice, this list of conditions and the following disclaimer. ! 38: * 2. Redistributions in binary form must reproduce the above copyright ! 39: * notice, this list of conditions and the following disclaimer in the ! 40: * documentation and/or other materials provided with the distribution. ! 41: * 3. All advertising materials mentioning features or use of this software ! 42: * must display the following acknowledgement: ! 43: * This product includes software developed by the University of ! 44: * California, Berkeley and its contributors. ! 45: * 4. Neither the name of the University nor the names of its contributors ! 46: * may be used to endorse or promote products derived from this software ! 47: * without specific prior written permission. ! 48: * ! 49: * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND ! 50: * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE ! 51: * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ! 52: * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE ! 53: * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL ! 54: * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS ! 55: * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) ! 56: * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT ! 57: * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY ! 58: * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF ! 59: * SUCH DAMAGE. ! 60: * ! 61: * @(#)null_vnops.c 8.6 (Berkeley) 5/27/95 ! 62: * ! 63: * Ancestors: ! 64: * @(#)lofs_vnops.c 1.2 (Berkeley) 6/18/92 ! 65: * ...and... ! 66: * @(#)null_vnodeops.c 1.20 92/07/07 UCLA Ficus project ! 67: */ ! 68: ! 69: /* ! 70: * Null Layer ! 71: * ! 72: * (See mount_null(8) for more information.) ! 73: * ! 74: * The null layer duplicates a portion of the file system ! 75: * name space under a new name. In this respect, it is ! 76: * similar to the loopback file system. It differs from ! 77: * the loopback fs in two respects: it is implemented using ! 78: * a stackable layers techniques, and it's "null-node"s stack above ! 79: * all lower-layer vnodes, not just over directory vnodes. ! 80: * ! 81: * The null layer has two purposes. First, it serves as a demonstration ! 82: * of layering by proving a layer which does nothing. (It actually ! 83: * does everything the loopback file system does, which is slightly ! 84: * more than nothing.) Second, the null layer can serve as a prototype ! 85: * layer. Since it provides all necessary layer framework, ! 86: * new file system layers can be created very easily be starting ! 87: * with a null layer. ! 88: * ! 89: * The remainder of this man page examines the null layer as a basis ! 90: * for constructing new layers. ! 91: * ! 92: * ! 93: * INSTANTIATING NEW NULL LAYERS ! 94: * ! 95: * New null layers are created with mount_null(8). ! 96: * Mount_null(8) takes two arguments, the pathname ! 97: * of the lower vfs (target-pn) and the pathname where the null ! 98: * layer will appear in the namespace (alias-pn). After ! 99: * the null layer is put into place, the contents ! 100: * of target-pn subtree will be aliased under alias-pn. ! 101: * ! 102: * ! 103: * OPERATION OF A NULL LAYER ! 104: * ! 105: * The null layer is the minimum file system layer, ! 106: * simply bypassing all possible operations to the lower layer ! 107: * for processing there. The majority of its activity centers ! 108: * on the bypass routine, though which nearly all vnode operations ! 109: * pass. ! 110: * ! 111: * The bypass routine accepts arbitrary vnode operations for ! 112: * handling by the lower layer. It begins by examing vnode ! 113: * operation arguments and replacing any null-nodes by their ! 114: * lower-layer equivlants. It then invokes the operation ! 115: * on the lower layer. Finally, it replaces the null-nodes ! 116: * in the arguments and, if a vnode is return by the operation, ! 117: * stacks a null-node on top of the returned vnode. ! 118: * ! 119: * Although bypass handles most operations, vop_getattr, vop_lock, ! 120: * vop_unlock, vop_inactive, vop_reclaim, and vop_print are not ! 121: * bypassed. Vop_getattr must change the fsid being returned. ! 122: * Vop_lock and vop_unlock must handle any locking for the ! 123: * current vnode as well as pass the lock request down. ! 124: * Vop_inactive and vop_reclaim are not bypassed so that ! 125: * they can handle freeing null-layer specific data. Vop_print ! 126: * is not bypassed to avoid excessive debugging information. ! 127: * Also, certain vnode operations change the locking state within ! 128: * the operation (create, mknod, remove, link, rename, mkdir, rmdir, ! 129: * and symlink). Ideally these operations should not change the ! 130: * lock state, but should be changed to let the caller of the ! 131: * function unlock them. Otherwise all intermediate vnode layers ! 132: * (such as union, umapfs, etc) must catch these functions to do ! 133: * the necessary locking at their layer. ! 134: * ! 135: * ! 136: * INSTANTIATING VNODE STACKS ! 137: * ! 138: * Mounting associates the null layer with a lower layer, ! 139: * effect stacking two VFSes. Vnode stacks are instead ! 140: * created on demand as files are accessed. ! 141: * ! 142: * The initial mount creates a single vnode stack for the ! 143: * root of the new null layer. All other vnode stacks ! 144: * are created as a result of vnode operations on ! 145: * this or other null vnode stacks. ! 146: * ! 147: * New vnode stacks come into existance as a result of ! 148: * an operation which returns a vnode. ! 149: * The bypass routine stacks a null-node above the new ! 150: * vnode before returning it to the caller. ! 151: * ! 152: * For example, imagine mounting a null layer with ! 153: * "mount_null /usr/include /dev/layer/null". ! 154: * Changing directory to /dev/layer/null will assign ! 155: * the root null-node (which was created when the null layer was mounted). ! 156: * Now consider opening "sys". A vop_lookup would be ! 157: * done on the root null-node. This operation would bypass through ! 158: * to the lower layer which would return a vnode representing ! 159: * the UFS "sys". Null_bypass then builds a null-node ! 160: * aliasing the UFS "sys" and returns this to the caller. ! 161: * Later operations on the null-node "sys" will repeat this ! 162: * process when constructing other vnode stacks. ! 163: * ! 164: * ! 165: * CREATING OTHER FILE SYSTEM LAYERS ! 166: * ! 167: * One of the easiest ways to construct new file system layers is to make ! 168: * a copy of the null layer, rename all files and variables, and ! 169: * then begin modifing the copy. Sed can be used to easily rename ! 170: * all variables. ! 171: * ! 172: * The umap layer is an example of a layer descended from the ! 173: * null layer. ! 174: * ! 175: * ! 176: * INVOKING OPERATIONS ON LOWER LAYERS ! 177: * ! 178: * There are two techniques to invoke operations on a lower layer ! 179: * when the operation cannot be completely bypassed. Each method ! 180: * is appropriate in different situations. In both cases, ! 181: * it is the responsibility of the aliasing layer to make ! 182: * the operation arguments "correct" for the lower layer ! 183: * by mapping an vnode arguments to the lower layer. ! 184: * ! 185: * The first approach is to call the aliasing layer's bypass routine. ! 186: * This method is most suitable when you wish to invoke the operation ! 187: * currently being hanldled on the lower layer. It has the advantage ! 188: * that the bypass routine already must do argument mapping. ! 189: * An example of this is null_getattrs in the null layer. ! 190: * ! 191: * A second approach is to directly invoked vnode operations on ! 192: * the lower layer with the VOP_OPERATIONNAME interface. ! 193: * The advantage of this method is that it is easy to invoke ! 194: * arbitrary operations on the lower layer. The disadvantage ! 195: * is that vnodes arguments must be manualy mapped. ! 196: * ! 197: */ ! 198: ! 199: #include <sys/param.h> ! 200: #include <sys/systm.h> ! 201: #include <sys/proc.h> ! 202: #include <sys/time.h> ! 203: #include <sys/types.h> ! 204: #include <sys/vnode.h> ! 205: #include <sys/mount.h> ! 206: #include <sys/namei.h> ! 207: #include <sys/malloc.h> ! 208: #include <sys/buf.h> ! 209: #include <miscfs/nullfs/null.h> ! 210: ! 211: ! 212: int null_bug_bypass = 0; /* for debugging: enables bypass printf'ing */ ! 213: ! 214: /* ! 215: * This is the 10-Apr-92 bypass routine. ! 216: * This version has been optimized for speed, throwing away some ! 217: * safety checks. It should still always work, but it's not as ! 218: * robust to programmer errors. ! 219: * Define SAFETY to include some error checking code. ! 220: * ! 221: * In general, we map all vnodes going down and unmap them on the way back. ! 222: * As an exception to this, vnodes can be marked "unmapped" by setting ! 223: * the Nth bit in operation's vdesc_flags. ! 224: * ! 225: * Also, some BSD vnode operations have the side effect of vrele'ing ! 226: * their arguments. With stacking, the reference counts are held ! 227: * by the upper node, not the lower one, so we must handle these ! 228: * side-effects here. This is not of concern in Sun-derived systems ! 229: * since there are no such side-effects. ! 230: * ! 231: * This makes the following assumptions: ! 232: * - only one returned vpp ! 233: * - no INOUT vpp's (Sun's vop_open has one of these) ! 234: * - the vnode operation vector of the first vnode should be used ! 235: * to determine what implementation of the op should be invoked ! 236: * - all mapped vnodes are of our vnode-type (NEEDSWORK: ! 237: * problems on rmdir'ing mount points and renaming?) ! 238: */ ! 239: int ! 240: null_bypass(ap) ! 241: struct vop_generic_args /* { ! 242: struct vnodeop_desc *a_desc; ! 243: <other random data follows, presumably> ! 244: } */ *ap; ! 245: { ! 246: extern int (**null_vnodeop_p)(); /* not extern, really "forward" */ ! 247: register struct vnode **this_vp_p; ! 248: int error; ! 249: struct vnode *old_vps[VDESC_MAX_VPS]; ! 250: struct vnode **vps_p[VDESC_MAX_VPS]; ! 251: struct vnode ***vppp; ! 252: struct vnodeop_desc *descp = ap->a_desc; ! 253: int reles, i; ! 254: ! 255: if (null_bug_bypass) ! 256: printf ("null_bypass: %s\n", descp->vdesc_name); ! 257: ! 258: #ifdef SAFETY ! 259: /* ! 260: * We require at least one vp. ! 261: */ ! 262: if (descp->vdesc_vp_offsets == NULL || ! 263: descp->vdesc_vp_offsets[0] == VDESC_NO_OFFSET) ! 264: panic ("null_bypass: no vp's in map.\n"); ! 265: #endif ! 266: ! 267: /* ! 268: * Map the vnodes going in. ! 269: * Later, we'll invoke the operation based on ! 270: * the first mapped vnode's operation vector. ! 271: */ ! 272: reles = descp->vdesc_flags; ! 273: for (i = 0; i < VDESC_MAX_VPS; reles >>= 1, i++) { ! 274: if (descp->vdesc_vp_offsets[i] == VDESC_NO_OFFSET) ! 275: break; /* bail out at end of list */ ! 276: vps_p[i] = this_vp_p = ! 277: VOPARG_OFFSETTO(struct vnode**,descp->vdesc_vp_offsets[i],ap); ! 278: /* ! 279: * We're not guaranteed that any but the first vnode ! 280: * are of our type. Check for and don't map any ! 281: * that aren't. (We must always map first vp or vclean fails.) ! 282: */ ! 283: if (i && (*this_vp_p == NULL || ! 284: (*this_vp_p)->v_op != null_vnodeop_p)) { ! 285: old_vps[i] = NULL; ! 286: } else { ! 287: old_vps[i] = *this_vp_p; ! 288: *(vps_p[i]) = NULLVPTOLOWERVP(*this_vp_p); ! 289: /* ! 290: * XXX - Several operations have the side effect ! 291: * of vrele'ing their vp's. We must account for ! 292: * that. (This should go away in the future.) ! 293: */ ! 294: if (reles & 1) ! 295: VREF(*this_vp_p); ! 296: } ! 297: ! 298: } ! 299: ! 300: /* ! 301: * Call the operation on the lower layer ! 302: * with the modified argument structure. ! 303: */ ! 304: error = VCALL(*(vps_p[0]), descp->vdesc_offset, ap); ! 305: ! 306: /* ! 307: * Maintain the illusion of call-by-value ! 308: * by restoring vnodes in the argument structure ! 309: * to their original value. ! 310: */ ! 311: reles = descp->vdesc_flags; ! 312: for (i = 0; i < VDESC_MAX_VPS; reles >>= 1, i++) { ! 313: if (descp->vdesc_vp_offsets[i] == VDESC_NO_OFFSET) ! 314: break; /* bail out at end of list */ ! 315: if (old_vps[i]) { ! 316: *(vps_p[i]) = old_vps[i]; ! 317: if (reles & 1) ! 318: vrele(*(vps_p[i])); ! 319: } ! 320: } ! 321: ! 322: /* ! 323: * Map the possible out-going vpp ! 324: * (Assumes that the lower layer always returns ! 325: * a VREF'ed vpp unless it gets an error.) ! 326: */ ! 327: if (descp->vdesc_vpp_offset != VDESC_NO_OFFSET && ! 328: !(descp->vdesc_flags & VDESC_NOMAP_VPP) && ! 329: !error) { ! 330: /* ! 331: * XXX - even though some ops have vpp returned vp's, ! 332: * several ops actually vrele this before returning. ! 333: * We must avoid these ops. ! 334: * (This should go away when these ops are regularized.) ! 335: */ ! 336: if (descp->vdesc_flags & VDESC_VPP_WILLRELE) ! 337: goto out; ! 338: vppp = VOPARG_OFFSETTO(struct vnode***, ! 339: descp->vdesc_vpp_offset,ap); ! 340: error = null_node_create(old_vps[0]->v_mount, **vppp, *vppp); ! 341: } ! 342: ! 343: out: ! 344: return (error); ! 345: } ! 346: ! 347: /* ! 348: * We have to carry on the locking protocol on the null layer vnodes ! 349: * as we progress through the tree. We also have to enforce read-only ! 350: * if this layer is mounted read-only. ! 351: */ ! 352: null_lookup(ap) ! 353: struct vop_lookup_args /* { ! 354: struct vnode * a_dvp; ! 355: struct vnode ** a_vpp; ! 356: struct componentname * a_cnp; ! 357: } */ *ap; ! 358: { ! 359: struct componentname *cnp = ap->a_cnp; ! 360: struct proc *p = cnp->cn_proc; ! 361: int flags = cnp->cn_flags; ! 362: struct vop_lock_args lockargs; ! 363: struct vop_unlock_args unlockargs; ! 364: struct vnode *dvp, *vp; ! 365: int error; ! 366: ! 367: if ((flags & ISLASTCN) && (ap->a_dvp->v_mount->mnt_flag & MNT_RDONLY) && ! 368: (cnp->cn_nameiop == DELETE || cnp->cn_nameiop == RENAME)) ! 369: return (EROFS); ! 370: error = null_bypass(ap); ! 371: if (error == EJUSTRETURN && (flags & ISLASTCN) && ! 372: (ap->a_dvp->v_mount->mnt_flag & MNT_RDONLY) && ! 373: (cnp->cn_nameiop == CREATE || cnp->cn_nameiop == RENAME)) ! 374: error = EROFS; ! 375: /* ! 376: * We must do the same locking and unlocking at this layer as ! 377: * is done in the layers below us. We could figure this out ! 378: * based on the error return and the LASTCN, LOCKPARENT, and ! 379: * LOCKLEAF flags. However, it is more expidient to just find ! 380: * out the state of the lower level vnodes and set ours to the ! 381: * same state. ! 382: */ ! 383: dvp = ap->a_dvp; ! 384: vp = *ap->a_vpp; ! 385: if (dvp == vp) ! 386: return (error); ! 387: if (!VOP_ISLOCKED(dvp)) { ! 388: unlockargs.a_vp = dvp; ! 389: unlockargs.a_flags = 0; ! 390: unlockargs.a_p = p; ! 391: vop_nounlock(&unlockargs); ! 392: } ! 393: if (vp != NULL && VOP_ISLOCKED(vp)) { ! 394: lockargs.a_vp = vp; ! 395: lockargs.a_flags = LK_SHARED; ! 396: lockargs.a_p = p; ! 397: vop_nolock(&lockargs); ! 398: } ! 399: return (error); ! 400: } ! 401: ! 402: /* ! 403: * Setattr call. Disallow write attempts if the layer is mounted read-only. ! 404: */ ! 405: int ! 406: null_setattr(ap) ! 407: struct vop_setattr_args /* { ! 408: struct vnodeop_desc *a_desc; ! 409: struct vnode *a_vp; ! 410: struct vattr *a_vap; ! 411: struct ucred *a_cred; ! 412: struct proc *a_p; ! 413: } */ *ap; ! 414: { ! 415: struct vnode *vp = ap->a_vp; ! 416: struct vattr *vap = ap->a_vap; ! 417: ! 418: if ((vap->va_flags != VNOVAL || vap->va_uid != (uid_t)VNOVAL || ! 419: vap->va_gid != (gid_t)VNOVAL || vap->va_atime.tv_sec != VNOVAL || ! 420: vap->va_mtime.tv_sec != VNOVAL || vap->va_mode != (mode_t)VNOVAL) && ! 421: (vp->v_mount->mnt_flag & MNT_RDONLY)) ! 422: return (EROFS); ! 423: if (vap->va_size != VNOVAL) { ! 424: switch (vp->v_type) { ! 425: case VDIR: ! 426: return (EISDIR); ! 427: case VCHR: ! 428: case VBLK: ! 429: case VSOCK: ! 430: case VFIFO: ! 431: return (0); ! 432: case VREG: ! 433: case VLNK: ! 434: default: ! 435: /* ! 436: * Disallow write attempts if the filesystem is ! 437: * mounted read-only. ! 438: */ ! 439: if (vp->v_mount->mnt_flag & MNT_RDONLY) ! 440: return (EROFS); ! 441: } ! 442: } ! 443: return (null_bypass(ap)); ! 444: } ! 445: ! 446: /* ! 447: * We handle getattr only to change the fsid. ! 448: */ ! 449: int ! 450: null_getattr(ap) ! 451: struct vop_getattr_args /* { ! 452: struct vnode *a_vp; ! 453: struct vattr *a_vap; ! 454: struct ucred *a_cred; ! 455: struct proc *a_p; ! 456: } */ *ap; ! 457: { ! 458: int error; ! 459: ! 460: if (error = null_bypass(ap)) ! 461: return (error); ! 462: /* Requires that arguments be restored. */ ! 463: ap->a_vap->va_fsid = ap->a_vp->v_mount->mnt_stat.f_fsid.val[0]; ! 464: return (0); ! 465: } ! 466: ! 467: int ! 468: null_access(ap) ! 469: struct vop_access_args /* { ! 470: struct vnode *a_vp; ! 471: int a_mode; ! 472: struct ucred *a_cred; ! 473: struct proc *a_p; ! 474: } */ *ap; ! 475: { ! 476: struct vnode *vp = ap->a_vp; ! 477: mode_t mode = ap->a_mode; ! 478: ! 479: /* ! 480: * Disallow write attempts on read-only layers; ! 481: * unless the file is a socket, fifo, or a block or ! 482: * character device resident on the file system. ! 483: */ ! 484: if (mode & VWRITE) { ! 485: switch (vp->v_type) { ! 486: case VDIR: ! 487: case VLNK: ! 488: case VREG: ! 489: if (vp->v_mount->mnt_flag & MNT_RDONLY) ! 490: return (EROFS); ! 491: break; ! 492: } ! 493: } ! 494: return (null_bypass(ap)); ! 495: } ! 496: ! 497: /* ! 498: * We need to process our own vnode lock and then clear the ! 499: * interlock flag as it applies only to our vnode, not the ! 500: * vnodes below us on the stack. ! 501: */ ! 502: int ! 503: null_lock(ap) ! 504: struct vop_lock_args /* { ! 505: struct vnode *a_vp; ! 506: int a_flags; ! 507: struct proc *a_p; ! 508: } */ *ap; ! 509: { ! 510: ! 511: vop_nolock(ap); ! 512: if ((ap->a_flags & LK_TYPE_MASK) == LK_DRAIN) ! 513: return (0); ! 514: ap->a_flags &= ~LK_INTERLOCK; ! 515: return (null_bypass(ap)); ! 516: } ! 517: ! 518: /* ! 519: * We need to process our own vnode unlock and then clear the ! 520: * interlock flag as it applies only to our vnode, not the ! 521: * vnodes below us on the stack. ! 522: */ ! 523: int ! 524: null_unlock(ap) ! 525: struct vop_unlock_args /* { ! 526: struct vnode *a_vp; ! 527: int a_flags; ! 528: struct proc *a_p; ! 529: } */ *ap; ! 530: { ! 531: struct vnode *vp = ap->a_vp; ! 532: ! 533: vop_nounlock(ap); ! 534: ap->a_flags &= ~LK_INTERLOCK; ! 535: return (null_bypass(ap)); ! 536: } ! 537: ! 538: int ! 539: null_inactive(ap) ! 540: struct vop_inactive_args /* { ! 541: struct vnode *a_vp; ! 542: struct proc *a_p; ! 543: } */ *ap; ! 544: { ! 545: /* ! 546: * Do nothing (and _don't_ bypass). ! 547: * Wait to vrele lowervp until reclaim, ! 548: * so that until then our null_node is in the ! 549: * cache and reusable. ! 550: * ! 551: * NEEDSWORK: Someday, consider inactive'ing ! 552: * the lowervp and then trying to reactivate it ! 553: * with capabilities (v_id) ! 554: * like they do in the name lookup cache code. ! 555: * That's too much work for now. ! 556: */ ! 557: VOP_UNLOCK(ap->a_vp, 0, ap->a_p); ! 558: return (0); ! 559: } ! 560: ! 561: int ! 562: null_reclaim(ap) ! 563: struct vop_reclaim_args /* { ! 564: struct vnode *a_vp; ! 565: struct proc *a_p; ! 566: } */ *ap; ! 567: { ! 568: struct vnode *vp = ap->a_vp; ! 569: struct null_node *xp = VTONULL(vp); ! 570: struct vnode *lowervp = xp->null_lowervp; ! 571: ! 572: /* ! 573: * Note: in vop_reclaim, vp->v_op == dead_vnodeop_p, ! 574: * so we can't call VOPs on ourself. ! 575: */ ! 576: /* After this assignment, this node will not be re-used. */ ! 577: xp->null_lowervp = NULL; ! 578: LIST_REMOVE(xp, null_hash); ! 579: FREE(vp->v_data, M_TEMP); ! 580: vp->v_data = NULL; ! 581: vrele (lowervp); ! 582: return (0); ! 583: } ! 584: ! 585: int ! 586: null_print(ap) ! 587: struct vop_print_args /* { ! 588: struct vnode *a_vp; ! 589: } */ *ap; ! 590: { ! 591: register struct vnode *vp = ap->a_vp; ! 592: printf ("\ttag VT_NULLFS, vp=%x, lowervp=%x\n", vp, NULLVPTOLOWERVP(vp)); ! 593: return (0); ! 594: } ! 595: ! 596: /* ! 597: * XXX - vop_strategy must be hand coded because it has no ! 598: * vnode in its arguments. ! 599: * This goes away with a merged VM/buffer cache. ! 600: */ ! 601: int ! 602: null_strategy(ap) ! 603: struct vop_strategy_args /* { ! 604: struct buf *a_bp; ! 605: } */ *ap; ! 606: { ! 607: struct buf *bp = ap->a_bp; ! 608: int error; ! 609: struct vnode *savedvp; ! 610: ! 611: savedvp = bp->b_vp; ! 612: bp->b_vp = NULLVPTOLOWERVP(bp->b_vp); ! 613: ! 614: error = VOP_STRATEGY(bp); ! 615: ! 616: bp->b_vp = savedvp; ! 617: ! 618: return (error); ! 619: } ! 620: ! 621: /* ! 622: * XXX - like vop_strategy, vop_bwrite must be hand coded because it has no ! 623: * vnode in its arguments. ! 624: * This goes away with a merged VM/buffer cache. ! 625: */ ! 626: int ! 627: null_bwrite(ap) ! 628: struct vop_bwrite_args /* { ! 629: struct buf *a_bp; ! 630: } */ *ap; ! 631: { ! 632: struct buf *bp = ap->a_bp; ! 633: int error; ! 634: struct vnode *savedvp; ! 635: ! 636: savedvp = bp->b_vp; ! 637: bp->b_vp = NULLVPTOLOWERVP(bp->b_vp); ! 638: ! 639: error = VOP_BWRITE(bp); ! 640: ! 641: bp->b_vp = savedvp; ! 642: ! 643: return (error); ! 644: } ! 645: ! 646: /* ! 647: * Global vfs data structures ! 648: */ ! 649: int (**null_vnodeop_p)(); ! 650: struct vnodeopv_entry_desc null_vnodeop_entries[] = { ! 651: { &vop_default_desc, null_bypass }, ! 652: ! 653: { &vop_lookup_desc, null_lookup }, ! 654: { &vop_setattr_desc, null_setattr }, ! 655: { &vop_getattr_desc, null_getattr }, ! 656: { &vop_access_desc, null_access }, ! 657: { &vop_lock_desc, null_lock }, ! 658: { &vop_unlock_desc, null_unlock }, ! 659: { &vop_inactive_desc, null_inactive }, ! 660: { &vop_reclaim_desc, null_reclaim }, ! 661: { &vop_print_desc, null_print }, ! 662: ! 663: { &vop_strategy_desc, null_strategy }, ! 664: { &vop_bwrite_desc, null_bwrite }, ! 665: ! 666: { (struct vnodeop_desc*)NULL, (int(*)())NULL } ! 667: }; ! 668: struct vnodeopv_desc null_vnodeop_opv_desc = ! 669: { &null_vnodeop_p, null_vnodeop_entries };
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