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1.1 ! root 1: /* ! 2: * Copyright (c) 2000 Apple Computer, Inc. All rights reserved. ! 3: * ! 4: * @APPLE_LICENSE_HEADER_START@ ! 5: * ! 6: * The contents of this file constitute Original Code as defined in and ! 7: * are subject to the Apple Public Source License Version 1.1 (the ! 8: * "License"). You may not use this file except in compliance with the ! 9: * License. Please obtain a copy of the License at ! 10: * http://www.apple.com/publicsource and read it before using this file. ! 11: * ! 12: * This Original Code and all software distributed under the License are ! 13: * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER ! 14: * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, ! 15: * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, ! 16: * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT. Please see the ! 17: * License for the specific language governing rights and limitations ! 18: * under the License. ! 19: * ! 20: * @APPLE_LICENSE_HEADER_END@ ! 21: */ ! 22: /* Copyright (c) 1995 NeXT Computer, Inc. All Rights Reserved */ ! 23: /* ! 24: * Copyright (c) 1992, 1993 ! 25: * The Regents of the University of California. All rights reserved. ! 26: * ! 27: * This code is derived from software contributed to Berkeley by ! 28: * John Heidemann of the UCLA Ficus project. ! 29: * ! 30: * Redistribution and use in source and binary forms, with or without ! 31: * modification, are permitted provided that the following conditions ! 32: * are met: ! 33: * 1. Redistributions of source code must retain the above copyright ! 34: * notice, this list of conditions and the following disclaimer. ! 35: * 2. Redistributions in binary form must reproduce the above copyright ! 36: * notice, this list of conditions and the following disclaimer in the ! 37: * documentation and/or other materials provided with the distribution. ! 38: * 3. All advertising materials mentioning features or use of this software ! 39: * must display the following acknowledgement: ! 40: * This product includes software developed by the University of ! 41: * California, Berkeley and its contributors. ! 42: * 4. Neither the name of the University nor the names of its contributors ! 43: * may be used to endorse or promote products derived from this software ! 44: * without specific prior written permission. ! 45: * ! 46: * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND ! 47: * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE ! 48: * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ! 49: * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE ! 50: * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL ! 51: * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS ! 52: * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) ! 53: * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT ! 54: * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY ! 55: * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF ! 56: * SUCH DAMAGE. ! 57: * ! 58: * @(#)null_vnops.c 8.6 (Berkeley) 5/27/95 ! 59: * ! 60: * Ancestors: ! 61: * @(#)lofs_vnops.c 1.2 (Berkeley) 6/18/92 ! 62: * ...and... ! 63: * @(#)null_vnodeops.c 1.20 92/07/07 UCLA Ficus project ! 64: */ ! 65: ! 66: /* ! 67: * Null Layer ! 68: * ! 69: * (See mount_null(8) for more information.) ! 70: * ! 71: * The null layer duplicates a portion of the file system ! 72: * name space under a new name. In this respect, it is ! 73: * similar to the loopback file system. It differs from ! 74: * the loopback fs in two respects: it is implemented using ! 75: * a stackable layers techniques, and it's "null-node"s stack above ! 76: * all lower-layer vnodes, not just over directory vnodes. ! 77: * ! 78: * The null layer has two purposes. First, it serves as a demonstration ! 79: * of layering by proving a layer which does nothing. (It actually ! 80: * does everything the loopback file system does, which is slightly ! 81: * more than nothing.) Second, the null layer can serve as a prototype ! 82: * layer. Since it provides all necessary layer framework, ! 83: * new file system layers can be created very easily be starting ! 84: * with a null layer. ! 85: * ! 86: * The remainder of this man page examines the null layer as a basis ! 87: * for constructing new layers. ! 88: * ! 89: * ! 90: * INSTANTIATING NEW NULL LAYERS ! 91: * ! 92: * New null layers are created with mount_null(8). ! 93: * Mount_null(8) takes two arguments, the pathname ! 94: * of the lower vfs (target-pn) and the pathname where the null ! 95: * layer will appear in the namespace (alias-pn). After ! 96: * the null layer is put into place, the contents ! 97: * of target-pn subtree will be aliased under alias-pn. ! 98: * ! 99: * ! 100: * OPERATION OF A NULL LAYER ! 101: * ! 102: * The null layer is the minimum file system layer, ! 103: * simply bypassing all possible operations to the lower layer ! 104: * for processing there. The majority of its activity centers ! 105: * on the bypass routine, though which nearly all vnode operations ! 106: * pass. ! 107: * ! 108: * The bypass routine accepts arbitrary vnode operations for ! 109: * handling by the lower layer. It begins by examing vnode ! 110: * operation arguments and replacing any null-nodes by their ! 111: * lower-layer equivlants. It then invokes the operation ! 112: * on the lower layer. Finally, it replaces the null-nodes ! 113: * in the arguments and, if a vnode is return by the operation, ! 114: * stacks a null-node on top of the returned vnode. ! 115: * ! 116: * Although bypass handles most operations, vop_getattr, vop_lock, ! 117: * vop_unlock, vop_inactive, vop_reclaim, and vop_print are not ! 118: * bypassed. Vop_getattr must change the fsid being returned. ! 119: * Vop_lock and vop_unlock must handle any locking for the ! 120: * current vnode as well as pass the lock request down. ! 121: * Vop_inactive and vop_reclaim are not bypassed so that ! 122: * they can handle freeing null-layer specific data. Vop_print ! 123: * is not bypassed to avoid excessive debugging information. ! 124: * Also, certain vnode operations change the locking state within ! 125: * the operation (create, mknod, remove, link, rename, mkdir, rmdir, ! 126: * and symlink). Ideally these operations should not change the ! 127: * lock state, but should be changed to let the caller of the ! 128: * function unlock them. Otherwise all intermediate vnode layers ! 129: * (such as union, umapfs, etc) must catch these functions to do ! 130: * the necessary locking at their layer. ! 131: * ! 132: * ! 133: * INSTANTIATING VNODE STACKS ! 134: * ! 135: * Mounting associates the null layer with a lower layer, ! 136: * effect stacking two VFSes. Vnode stacks are instead ! 137: * created on demand as files are accessed. ! 138: * ! 139: * The initial mount creates a single vnode stack for the ! 140: * root of the new null layer. All other vnode stacks ! 141: * are created as a result of vnode operations on ! 142: * this or other null vnode stacks. ! 143: * ! 144: * New vnode stacks come into existance as a result of ! 145: * an operation which returns a vnode. ! 146: * The bypass routine stacks a null-node above the new ! 147: * vnode before returning it to the caller. ! 148: * ! 149: * For example, imagine mounting a null layer with ! 150: * "mount_null /usr/include /dev/layer/null". ! 151: * Changing directory to /dev/layer/null will assign ! 152: * the root null-node (which was created when the null layer was mounted). ! 153: * Now consider opening "sys". A vop_lookup would be ! 154: * done on the root null-node. This operation would bypass through ! 155: * to the lower layer which would return a vnode representing ! 156: * the UFS "sys". Null_bypass then builds a null-node ! 157: * aliasing the UFS "sys" and returns this to the caller. ! 158: * Later operations on the null-node "sys" will repeat this ! 159: * process when constructing other vnode stacks. ! 160: * ! 161: * ! 162: * CREATING OTHER FILE SYSTEM LAYERS ! 163: * ! 164: * One of the easiest ways to construct new file system layers is to make ! 165: * a copy of the null layer, rename all files and variables, and ! 166: * then begin modifing the copy. Sed can be used to easily rename ! 167: * all variables. ! 168: * ! 169: * The umap layer is an example of a layer descended from the ! 170: * null layer. ! 171: * ! 172: * ! 173: * INVOKING OPERATIONS ON LOWER LAYERS ! 174: * ! 175: * There are two techniques to invoke operations on a lower layer ! 176: * when the operation cannot be completely bypassed. Each method ! 177: * is appropriate in different situations. In both cases, ! 178: * it is the responsibility of the aliasing layer to make ! 179: * the operation arguments "correct" for the lower layer ! 180: * by mapping an vnode arguments to the lower layer. ! 181: * ! 182: * The first approach is to call the aliasing layer's bypass routine. ! 183: * This method is most suitable when you wish to invoke the operation ! 184: * currently being hanldled on the lower layer. It has the advantage ! 185: * that the bypass routine already must do argument mapping. ! 186: * An example of this is null_getattrs in the null layer. ! 187: * ! 188: * A second approach is to directly invoked vnode operations on ! 189: * the lower layer with the VOP_OPERATIONNAME interface. ! 190: * The advantage of this method is that it is easy to invoke ! 191: * arbitrary operations on the lower layer. The disadvantage ! 192: * is that vnodes arguments must be manualy mapped. ! 193: * ! 194: */ ! 195: ! 196: #include <sys/param.h> ! 197: #include <sys/systm.h> ! 198: #include <sys/proc.h> ! 199: #include <sys/time.h> ! 200: #include <sys/types.h> ! 201: #include <sys/vnode.h> ! 202: #include <sys/mount.h> ! 203: #include <sys/namei.h> ! 204: #include <sys/malloc.h> ! 205: #include <sys/buf.h> ! 206: #include <miscfs/nullfs/null.h> ! 207: ! 208: ! 209: int null_bug_bypass = 0; /* for debugging: enables bypass printf'ing */ ! 210: ! 211: /* ! 212: * This is the 10-Apr-92 bypass routine. ! 213: * This version has been optimized for speed, throwing away some ! 214: * safety checks. It should still always work, but it's not as ! 215: * robust to programmer errors. ! 216: * Define SAFETY to include some error checking code. ! 217: * ! 218: * In general, we map all vnodes going down and unmap them on the way back. ! 219: * As an exception to this, vnodes can be marked "unmapped" by setting ! 220: * the Nth bit in operation's vdesc_flags. ! 221: * ! 222: * Also, some BSD vnode operations have the side effect of vrele'ing ! 223: * their arguments. With stacking, the reference counts are held ! 224: * by the upper node, not the lower one, so we must handle these ! 225: * side-effects here. This is not of concern in Sun-derived systems ! 226: * since there are no such side-effects. ! 227: * ! 228: * This makes the following assumptions: ! 229: * - only one returned vpp ! 230: * - no INOUT vpp's (Sun's vop_open has one of these) ! 231: * - the vnode operation vector of the first vnode should be used ! 232: * to determine what implementation of the op should be invoked ! 233: * - all mapped vnodes are of our vnode-type (NEEDSWORK: ! 234: * problems on rmdir'ing mount points and renaming?) ! 235: */ ! 236: int ! 237: null_bypass(ap) ! 238: struct vop_generic_args /* { ! 239: struct vnodeop_desc *a_desc; ! 240: <other random data follows, presumably> ! 241: } */ *ap; ! 242: { ! 243: extern int (**null_vnodeop_p)(); /* not extern, really "forward" */ ! 244: register struct vnode **this_vp_p; ! 245: int error; ! 246: struct vnode *old_vps[VDESC_MAX_VPS]; ! 247: struct vnode **vps_p[VDESC_MAX_VPS]; ! 248: struct vnode ***vppp; ! 249: struct vnodeop_desc *descp = ap->a_desc; ! 250: int reles, i; ! 251: ! 252: if (null_bug_bypass) ! 253: printf ("null_bypass: %s\n", descp->vdesc_name); ! 254: ! 255: #ifdef SAFETY ! 256: /* ! 257: * We require at least one vp. ! 258: */ ! 259: if (descp->vdesc_vp_offsets == NULL || ! 260: descp->vdesc_vp_offsets[0] == VDESC_NO_OFFSET) ! 261: panic ("null_bypass: no vp's in map.\n"); ! 262: #endif ! 263: ! 264: /* ! 265: * Map the vnodes going in. ! 266: * Later, we'll invoke the operation based on ! 267: * the first mapped vnode's operation vector. ! 268: */ ! 269: reles = descp->vdesc_flags; ! 270: for (i = 0; i < VDESC_MAX_VPS; reles >>= 1, i++) { ! 271: if (descp->vdesc_vp_offsets[i] == VDESC_NO_OFFSET) ! 272: break; /* bail out at end of list */ ! 273: vps_p[i] = this_vp_p = ! 274: VOPARG_OFFSETTO(struct vnode**,descp->vdesc_vp_offsets[i],ap); ! 275: /* ! 276: * We're not guaranteed that any but the first vnode ! 277: * are of our type. Check for and don't map any ! 278: * that aren't. (We must always map first vp or vclean fails.) ! 279: */ ! 280: if (i && (*this_vp_p == NULL || ! 281: (*this_vp_p)->v_op != null_vnodeop_p)) { ! 282: old_vps[i] = NULL; ! 283: } else { ! 284: old_vps[i] = *this_vp_p; ! 285: *(vps_p[i]) = NULLVPTOLOWERVP(*this_vp_p); ! 286: /* ! 287: * XXX - Several operations have the side effect ! 288: * of vrele'ing their vp's. We must account for ! 289: * that. (This should go away in the future.) ! 290: */ ! 291: if (reles & 1) ! 292: VREF(*this_vp_p); ! 293: } ! 294: ! 295: } ! 296: ! 297: /* ! 298: * Call the operation on the lower layer ! 299: * with the modified argument structure. ! 300: */ ! 301: error = VCALL(*(vps_p[0]), descp->vdesc_offset, ap); ! 302: ! 303: /* ! 304: * Maintain the illusion of call-by-value ! 305: * by restoring vnodes in the argument structure ! 306: * to their original value. ! 307: */ ! 308: reles = descp->vdesc_flags; ! 309: for (i = 0; i < VDESC_MAX_VPS; reles >>= 1, i++) { ! 310: if (descp->vdesc_vp_offsets[i] == VDESC_NO_OFFSET) ! 311: break; /* bail out at end of list */ ! 312: if (old_vps[i]) { ! 313: *(vps_p[i]) = old_vps[i]; ! 314: if (reles & 1) ! 315: vrele(*(vps_p[i])); ! 316: } ! 317: } ! 318: ! 319: /* ! 320: * Map the possible out-going vpp ! 321: * (Assumes that the lower layer always returns ! 322: * a VREF'ed vpp unless it gets an error.) ! 323: */ ! 324: if (descp->vdesc_vpp_offset != VDESC_NO_OFFSET && ! 325: !(descp->vdesc_flags & VDESC_NOMAP_VPP) && ! 326: !error) { ! 327: /* ! 328: * XXX - even though some ops have vpp returned vp's, ! 329: * several ops actually vrele this before returning. ! 330: * We must avoid these ops. ! 331: * (This should go away when these ops are regularized.) ! 332: */ ! 333: if (descp->vdesc_flags & VDESC_VPP_WILLRELE) ! 334: goto out; ! 335: vppp = VOPARG_OFFSETTO(struct vnode***, ! 336: descp->vdesc_vpp_offset,ap); ! 337: error = null_node_create(old_vps[0]->v_mount, **vppp, *vppp); ! 338: } ! 339: ! 340: out: ! 341: return (error); ! 342: } ! 343: ! 344: /* ! 345: * We have to carry on the locking protocol on the null layer vnodes ! 346: * as we progress through the tree. We also have to enforce read-only ! 347: * if this layer is mounted read-only. ! 348: */ ! 349: null_lookup(ap) ! 350: struct vop_lookup_args /* { ! 351: struct vnode * a_dvp; ! 352: struct vnode ** a_vpp; ! 353: struct componentname * a_cnp; ! 354: } */ *ap; ! 355: { ! 356: struct componentname *cnp = ap->a_cnp; ! 357: struct proc *p = cnp->cn_proc; ! 358: int flags = cnp->cn_flags; ! 359: struct vop_lock_args lockargs; ! 360: struct vop_unlock_args unlockargs; ! 361: struct vnode *dvp, *vp; ! 362: int error; ! 363: ! 364: if ((flags & ISLASTCN) && (ap->a_dvp->v_mount->mnt_flag & MNT_RDONLY) && ! 365: (cnp->cn_nameiop == DELETE || cnp->cn_nameiop == RENAME)) ! 366: return (EROFS); ! 367: error = null_bypass(ap); ! 368: if (error == EJUSTRETURN && (flags & ISLASTCN) && ! 369: (ap->a_dvp->v_mount->mnt_flag & MNT_RDONLY) && ! 370: (cnp->cn_nameiop == CREATE || cnp->cn_nameiop == RENAME)) ! 371: error = EROFS; ! 372: /* ! 373: * We must do the same locking and unlocking at this layer as ! 374: * is done in the layers below us. We could figure this out ! 375: * based on the error return and the LASTCN, LOCKPARENT, and ! 376: * LOCKLEAF flags. However, it is more expidient to just find ! 377: * out the state of the lower level vnodes and set ours to the ! 378: * same state. ! 379: */ ! 380: dvp = ap->a_dvp; ! 381: vp = *ap->a_vpp; ! 382: if (dvp == vp) ! 383: return (error); ! 384: if (!VOP_ISLOCKED(dvp)) { ! 385: unlockargs.a_vp = dvp; ! 386: unlockargs.a_flags = 0; ! 387: unlockargs.a_p = p; ! 388: vop_nounlock(&unlockargs); ! 389: } ! 390: if (vp != NULL && VOP_ISLOCKED(vp)) { ! 391: lockargs.a_vp = vp; ! 392: lockargs.a_flags = LK_SHARED; ! 393: lockargs.a_p = p; ! 394: vop_nolock(&lockargs); ! 395: } ! 396: return (error); ! 397: } ! 398: ! 399: /* ! 400: * Setattr call. Disallow write attempts if the layer is mounted read-only. ! 401: */ ! 402: int ! 403: null_setattr(ap) ! 404: struct vop_setattr_args /* { ! 405: struct vnodeop_desc *a_desc; ! 406: struct vnode *a_vp; ! 407: struct vattr *a_vap; ! 408: struct ucred *a_cred; ! 409: struct proc *a_p; ! 410: } */ *ap; ! 411: { ! 412: struct vnode *vp = ap->a_vp; ! 413: struct vattr *vap = ap->a_vap; ! 414: ! 415: if ((vap->va_flags != VNOVAL || vap->va_uid != (uid_t)VNOVAL || ! 416: vap->va_gid != (gid_t)VNOVAL || vap->va_atime.tv_sec != VNOVAL || ! 417: vap->va_mtime.tv_sec != VNOVAL || vap->va_mode != (mode_t)VNOVAL) && ! 418: (vp->v_mount->mnt_flag & MNT_RDONLY)) ! 419: return (EROFS); ! 420: if (vap->va_size != VNOVAL) { ! 421: switch (vp->v_type) { ! 422: case VDIR: ! 423: return (EISDIR); ! 424: case VCHR: ! 425: case VBLK: ! 426: case VSOCK: ! 427: case VFIFO: ! 428: return (0); ! 429: case VREG: ! 430: case VLNK: ! 431: default: ! 432: /* ! 433: * Disallow write attempts if the filesystem is ! 434: * mounted read-only. ! 435: */ ! 436: if (vp->v_mount->mnt_flag & MNT_RDONLY) ! 437: return (EROFS); ! 438: } ! 439: } ! 440: return (null_bypass(ap)); ! 441: } ! 442: ! 443: /* ! 444: * We handle getattr only to change the fsid. ! 445: */ ! 446: int ! 447: null_getattr(ap) ! 448: struct vop_getattr_args /* { ! 449: struct vnode *a_vp; ! 450: struct vattr *a_vap; ! 451: struct ucred *a_cred; ! 452: struct proc *a_p; ! 453: } */ *ap; ! 454: { ! 455: int error; ! 456: ! 457: if (error = null_bypass(ap)) ! 458: return (error); ! 459: /* Requires that arguments be restored. */ ! 460: ap->a_vap->va_fsid = ap->a_vp->v_mount->mnt_stat.f_fsid.val[0]; ! 461: return (0); ! 462: } ! 463: ! 464: int ! 465: null_access(ap) ! 466: struct vop_access_args /* { ! 467: struct vnode *a_vp; ! 468: int a_mode; ! 469: struct ucred *a_cred; ! 470: struct proc *a_p; ! 471: } */ *ap; ! 472: { ! 473: struct vnode *vp = ap->a_vp; ! 474: mode_t mode = ap->a_mode; ! 475: ! 476: /* ! 477: * Disallow write attempts on read-only layers; ! 478: * unless the file is a socket, fifo, or a block or ! 479: * character device resident on the file system. ! 480: */ ! 481: if (mode & VWRITE) { ! 482: switch (vp->v_type) { ! 483: case VDIR: ! 484: case VLNK: ! 485: case VREG: ! 486: if (vp->v_mount->mnt_flag & MNT_RDONLY) ! 487: return (EROFS); ! 488: break; ! 489: } ! 490: } ! 491: return (null_bypass(ap)); ! 492: } ! 493: ! 494: /* ! 495: * We need to process our own vnode lock and then clear the ! 496: * interlock flag as it applies only to our vnode, not the ! 497: * vnodes below us on the stack. ! 498: */ ! 499: int ! 500: null_lock(ap) ! 501: struct vop_lock_args /* { ! 502: struct vnode *a_vp; ! 503: int a_flags; ! 504: struct proc *a_p; ! 505: } */ *ap; ! 506: { ! 507: ! 508: vop_nolock(ap); ! 509: if ((ap->a_flags & LK_TYPE_MASK) == LK_DRAIN) ! 510: return (0); ! 511: ap->a_flags &= ~LK_INTERLOCK; ! 512: return (null_bypass(ap)); ! 513: } ! 514: ! 515: /* ! 516: * We need to process our own vnode unlock and then clear the ! 517: * interlock flag as it applies only to our vnode, not the ! 518: * vnodes below us on the stack. ! 519: */ ! 520: int ! 521: null_unlock(ap) ! 522: struct vop_unlock_args /* { ! 523: struct vnode *a_vp; ! 524: int a_flags; ! 525: struct proc *a_p; ! 526: } */ *ap; ! 527: { ! 528: struct vnode *vp = ap->a_vp; ! 529: ! 530: vop_nounlock(ap); ! 531: ap->a_flags &= ~LK_INTERLOCK; ! 532: return (null_bypass(ap)); ! 533: } ! 534: ! 535: int ! 536: null_inactive(ap) ! 537: struct vop_inactive_args /* { ! 538: struct vnode *a_vp; ! 539: struct proc *a_p; ! 540: } */ *ap; ! 541: { ! 542: /* ! 543: * Do nothing (and _don't_ bypass). ! 544: * Wait to vrele lowervp until reclaim, ! 545: * so that until then our null_node is in the ! 546: * cache and reusable. ! 547: * ! 548: * NEEDSWORK: Someday, consider inactive'ing ! 549: * the lowervp and then trying to reactivate it ! 550: * with capabilities (v_id) ! 551: * like they do in the name lookup cache code. ! 552: * That's too much work for now. ! 553: */ ! 554: VOP_UNLOCK(ap->a_vp, 0, ap->a_p); ! 555: return (0); ! 556: } ! 557: ! 558: int ! 559: null_reclaim(ap) ! 560: struct vop_reclaim_args /* { ! 561: struct vnode *a_vp; ! 562: struct proc *a_p; ! 563: } */ *ap; ! 564: { ! 565: struct vnode *vp = ap->a_vp; ! 566: struct null_node *xp = VTONULL(vp); ! 567: struct vnode *lowervp = xp->null_lowervp; ! 568: ! 569: /* ! 570: * Note: in vop_reclaim, vp->v_op == dead_vnodeop_p, ! 571: * so we can't call VOPs on ourself. ! 572: */ ! 573: /* After this assignment, this node will not be re-used. */ ! 574: xp->null_lowervp = NULL; ! 575: LIST_REMOVE(xp, null_hash); ! 576: FREE(vp->v_data, M_TEMP); ! 577: vp->v_data = NULL; ! 578: vrele (lowervp); ! 579: return (0); ! 580: } ! 581: ! 582: int ! 583: null_print(ap) ! 584: struct vop_print_args /* { ! 585: struct vnode *a_vp; ! 586: } */ *ap; ! 587: { ! 588: register struct vnode *vp = ap->a_vp; ! 589: printf ("\ttag VT_NULLFS, vp=%x, lowervp=%x\n", vp, NULLVPTOLOWERVP(vp)); ! 590: return (0); ! 591: } ! 592: ! 593: /* ! 594: * XXX - vop_strategy must be hand coded because it has no ! 595: * vnode in its arguments. ! 596: * This goes away with a merged VM/buffer cache. ! 597: */ ! 598: int ! 599: null_strategy(ap) ! 600: struct vop_strategy_args /* { ! 601: struct buf *a_bp; ! 602: } */ *ap; ! 603: { ! 604: struct buf *bp = ap->a_bp; ! 605: int error; ! 606: struct vnode *savedvp; ! 607: ! 608: savedvp = bp->b_vp; ! 609: bp->b_vp = NULLVPTOLOWERVP(bp->b_vp); ! 610: ! 611: error = VOP_STRATEGY(bp); ! 612: ! 613: bp->b_vp = savedvp; ! 614: ! 615: return (error); ! 616: } ! 617: ! 618: /* ! 619: * XXX - like vop_strategy, vop_bwrite must be hand coded because it has no ! 620: * vnode in its arguments. ! 621: * This goes away with a merged VM/buffer cache. ! 622: */ ! 623: int ! 624: null_bwrite(ap) ! 625: struct vop_bwrite_args /* { ! 626: struct buf *a_bp; ! 627: } */ *ap; ! 628: { ! 629: struct buf *bp = ap->a_bp; ! 630: int error; ! 631: struct vnode *savedvp; ! 632: ! 633: savedvp = bp->b_vp; ! 634: bp->b_vp = NULLVPTOLOWERVP(bp->b_vp); ! 635: ! 636: error = VOP_BWRITE(bp); ! 637: ! 638: bp->b_vp = savedvp; ! 639: ! 640: return (error); ! 641: } ! 642: ! 643: /* ! 644: * Global vfs data structures ! 645: */ ! 646: int (**null_vnodeop_p)(); ! 647: struct vnodeopv_entry_desc null_vnodeop_entries[] = { ! 648: { &vop_default_desc, null_bypass }, ! 649: ! 650: { &vop_lookup_desc, null_lookup }, ! 651: { &vop_setattr_desc, null_setattr }, ! 652: { &vop_getattr_desc, null_getattr }, ! 653: { &vop_access_desc, null_access }, ! 654: { &vop_lock_desc, null_lock }, ! 655: { &vop_unlock_desc, null_unlock }, ! 656: { &vop_inactive_desc, null_inactive }, ! 657: { &vop_reclaim_desc, null_reclaim }, ! 658: { &vop_print_desc, null_print }, ! 659: ! 660: { &vop_strategy_desc, null_strategy }, ! 661: { &vop_bwrite_desc, null_bwrite }, ! 662: ! 663: { (struct vnodeop_desc*)NULL, (int(*)())NULL } ! 664: }; ! 665: struct vnodeopv_desc null_vnodeop_opv_desc = ! 666: { &null_vnodeop_p, null_vnodeop_entries };
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