sys/vfs/ufs/ffs_inode.c

   1 /*
   2  * Copyright (c) 1982, 1986, 1989, 1993
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  * 4. Neither the name of the University nor the names of its contributors
  14  *    may be used to endorse or promote products derived from this software
  15  *    without specific prior written permission.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  27  * SUCH DAMAGE.
  28  *
  29  *      @(#)ffs_inode.c 8.13 (Berkeley) 4/21/95
  30  * $FreeBSD: src/sys/ufs/ffs/ffs_inode.c,v 1.56.2.5 2002/02/05 18:35:03 dillon Exp $
  31  */
  32
  33 #include "opt_quota.h"
  34
  35 #include <sys/param.h>
  36 #include <sys/systm.h>
  37 #include <sys/mount.h>
  38 #include <sys/proc.h>
  39 #include <sys/buf.h>
  40 #include <sys/vnode.h>
  41 #include <sys/kernel.h>
  42 #include <sys/malloc.h>
  43 #include <sys/resourcevar.h>
  44 #include <sys/vmmeter.h>
  45
  46 #include <vm/vm.h>
  47 #include <vm/vm_extern.h>
  48
  49 #include "quota.h"
  50 #include "ufsmount.h"
  51 #include "inode.h"
  52 #include "ufs_extern.h"
  53
  54 #include "fs.h"
  55 #include "ffs_extern.h"
  56
  57 #include <vm/vm_page2.h>
  58 #include <sys/buf2.h>
  59
  60 static int ffs_indirtrunc (struct inode *, ufs_daddr_t, ufs_daddr_t,
  61             ufs_daddr_t, int, long *);
  62
  63 /*
  64  * Update the access, modified, and inode change times as specified by the
  65  * IN_ACCESS, IN_UPDATE, and IN_CHANGE flags respectively.  Write the inode
  66  * to disk if the IN_MODIFIED flag is set (it may be set initially, or by
  67  * the timestamp update).  The IN_LAZYMOD flag is set to force a write
  68  * later if not now.  If we write now, then clear both IN_MODIFIED and
  69  * IN_LAZYMOD to reflect the presumably successful write, and if waitfor is
  70  * set, then wait for the write to complete.
  71  */
  72 int
  73 ffs_update(struct vnode *vp, int waitfor)
  74 {
  75         struct fs *fs;
  76         struct buf *bp;
  77         struct inode *ip;
  78         int error;
  79
  80         ufs_itimes(vp);
  81         ip = VTOI(vp);
  82         if ((ip->i_flag & IN_MODIFIED) == 0 && waitfor == 0)
  83                 return (0);
  84         ip->i_flag &= ~(IN_LAZYMOD | IN_MODIFIED);
  85         fs = ip->i_fs;
  86         if (fs->fs_ronly)
  87                 return (0);
  88
  89         /*
  90          * The vnode type is usually set to VBAD if an unrecoverable I/O
  91          * error has occured (such as when reading the inode).  Clear the
  92          * modified bits but do not write anything out in this case.
  93          */
  94         if (vp->v_type == VBAD)
  95                 return (0);
  96         /*
  97          * Ensure that uid and gid are correct. This is a temporary
  98          * fix until fsck has been changed to do the update.
  99          */
 100         if (fs->fs_inodefmt < FS_44INODEFMT) {          /* XXX */
 101                 ip->i_din.di_ouid = ip->i_uid;          /* XXX */
 102                 ip->i_din.di_ogid = ip->i_gid;          /* XXX */
 103         }                                               /* XXX */
 104         error = bread(ip->i_devvp,
 105                       fsbtodoff(fs, ino_to_fsba(fs, ip->i_number)),
 106                       (int)fs->fs_bsize, &bp);
 107         if (error) {
 108                 brelse(bp);
 109                 return (error);
 110         }
 111         if (DOINGSOFTDEP(vp))
 112                 softdep_update_inodeblock(ip, bp, waitfor);
 113         else if (ip->i_effnlink != ip->i_nlink)
 114                 panic("ffs_update: bad link cnt");
 115         *((struct ufs1_dinode *)bp->b_data +
 116             ino_to_fsbo(fs, ip->i_number)) = ip->i_din;
 117         if (waitfor && !DOINGASYNC(vp)) {
 118                 return (bwrite(bp));
 119         } else if (vm_page_count_severe() || buf_dirty_count_severe()) {
 120                 return (bwrite(bp));
 121         } else {
 122                 if (bp->b_bufsize == fs->fs_bsize)
 123                         bp->b_flags |= B_CLUSTEROK;
 124                 bdwrite(bp);
 125                 return (0);
 126         }
 127 }
 128
 129 #define SINGLE  0       /* index of single indirect block */
 130 #define DOUBLE  1       /* index of double indirect block */
 131 #define TRIPLE  2       /* index of triple indirect block */
 132 /*
 133  * Truncate the inode oip to at most length size, freeing the
 134  * disk blocks.
 135  */
 136 int
 137 ffs_truncate(struct vnode *vp, off_t length, int flags, struct ucred *cred)
 138 {
 139         struct vnode *ovp = vp;
 140         ufs_daddr_t lastblock;
 141         struct inode *oip;
 142         ufs_daddr_t bn, lbn, lastiblock[NIADDR], indir_lbn[NIADDR];
 143         ufs_daddr_t oldblks[NDADDR + NIADDR], newblks[NDADDR + NIADDR];
 144         struct fs *fs;
 145         struct buf *bp;
 146         int offset, size, level;
 147         long count, nblocks, blocksreleased = 0;
 148         int i;
 149         int aflags, error, allerror;
 150         off_t osize;
 151
 152         oip = VTOI(ovp);
 153         fs = oip->i_fs;
 154         if (length < 0)
 155                 return (EINVAL);
 156         if (length > fs->fs_maxfilesize)
 157                 return (EFBIG);
 158         if (ovp->v_type == VLNK &&
 159             (oip->i_size < ovp->v_mount->mnt_maxsymlinklen || oip->i_din.di_blocks == 0)) {
 160 #ifdef DIAGNOSTIC
 161                 if (length != 0)
 162                         panic("ffs_truncate: partial truncate of symlink");
 163 #endif /* DIAGNOSTIC */
 164                 bzero((char *)&oip->i_shortlink, (uint)oip->i_size);
 165                 oip->i_size = 0;
 166                 oip->i_flag |= IN_CHANGE | IN_UPDATE;
 167                 return (ffs_update(ovp, 1));
 168         }
 169         if (oip->i_size == length) {
 170                 oip->i_flag |= IN_CHANGE | IN_UPDATE;
 171                 return (ffs_update(ovp, 0));
 172         }
 173         if (fs->fs_ronly)
 174                 panic("ffs_truncate: read-only filesystem");
 175 #ifdef QUOTA
 176         error = ufs_getinoquota(oip);
 177         if (error)
 178                 return (error);
 179 #endif
 180         ovp->v_lasta = ovp->v_clen = ovp->v_cstart = ovp->v_lastw = 0;
 181         if (DOINGSOFTDEP(ovp)) {
 182                 if (length > 0 || softdep_slowdown(ovp)) {
 183                         /*
 184                          * If a file is only partially truncated, then
 185                          * we have to clean up the data structures
 186                          * describing the allocation past the truncation
 187                          * point. Finding and deallocating those structures
 188                          * is a lot of work. Since partial truncation occurs
 189                          * rarely, we solve the problem by syncing the file
 190                          * so that it will have no data structures left.
 191                          */
 192                         if ((error = VOP_FSYNC(ovp, MNT_WAIT, 0)) != 0)
 193                                 return (error);
 194                 } else {
 195 #ifdef QUOTA
 196                         (void) ufs_chkdq(oip, -oip->i_blocks, NOCRED, 0);
 197 #endif
 198                         softdep_setup_freeblocks(oip, length);
 199                         vinvalbuf(ovp, 0, 0, 0);
 200                         nvnode_pager_setsize(ovp, 0, fs->fs_bsize, 0);
 201                         oip->i_flag |= IN_CHANGE | IN_UPDATE;
 202                         return (ffs_update(ovp, 0));
 203                 }
 204         }
 205         osize = oip->i_size;
 206
 207         /*
 208          * Lengthen the size of the file. We must ensure that the
 209          * last byte of the file is allocated. Since the smallest
 210          * value of osize is 0, length will be at least 1.
 211          *
 212          * nvextendbuf() only breads the old buffer.  The blocksize
 213          * of the new buffer must be specified so it knows how large
 214          * to make the VM object.
 215          */
 216         if (osize < length) {
 217                 nvextendbuf(vp, osize, length,
 218                             blkoffsize(fs, oip, osize), /* oblksize */
 219                             blkoffresize(fs, length),   /* nblksize */
 220                             blkoff(fs, osize),
 221                             blkoff(fs, length),
 222                             0);
 223
 224                 aflags = B_CLRBUF;
 225                 if (flags & IO_SYNC)
 226                         aflags |= B_SYNC;
 227                 /* BALLOC will reallocate the fragment at the old EOF */
 228                 error = VOP_BALLOC(ovp, length - 1, 1, cred, aflags, &bp);
 229                 if (error)
 230                         return (error);
 231                 oip->i_size = length;
 232                 if (bp->b_bufsize == fs->fs_bsize)
 233                         bp->b_flags |= B_CLUSTEROK;
 234                 if (aflags & B_SYNC)
 235                         bwrite(bp);
 236                 else
 237                         bawrite(bp);
 238                 oip->i_flag |= IN_CHANGE | IN_UPDATE;
 239                 return (ffs_update(ovp, 1));
 240         }
 241
 242         /*
 243          * Shorten the size of the file.
 244          *
 245          * NOTE: The block size specified in nvtruncbuf() is the blocksize
 246          *       of the buffer containing length prior to any reallocation
 247          *       of the block.
 248          */
 249         allerror = nvtruncbuf(ovp, length, blkoffsize(fs, oip, length),
 250                               blkoff(fs, length), 0);
 251         offset = blkoff(fs, length);
 252         if (offset == 0) {
 253                 oip->i_size = length;
 254         } else {
 255                 lbn = lblkno(fs, length);
 256                 aflags = B_CLRBUF;
 257                 if (flags & IO_SYNC)
 258                         aflags |= B_SYNC;
 259                 error = VOP_BALLOC(ovp, length - 1, 1, cred, aflags, &bp);
 260                 if (error)
 261                         return (error);
 262
 263                 /*
 264                  * When we are doing soft updates and the UFS_BALLOC
 265                  * above fills in a direct block hole with a full sized
 266                  * block that will be truncated down to a fragment below,
 267                  * we must flush out the block dependency with an FSYNC
 268                  * so that we do not get a soft updates inconsistency
 269                  * when we create the fragment below.
 270                  *
 271                  * nvtruncbuf() may have re-dirtied the underlying block
 272                  * as part of its truncation zeroing code.  To avoid a
 273                  * 'locking against myself' panic in the second fsync we
 274                  * can simply undirty the bp since the redirtying was
 275                  * related to areas of the buffer that we are going to
 276                  * throw away anyway, and we will b*write() the remainder
 277                  * anyway down below.
 278                  */
 279                 if (DOINGSOFTDEP(ovp) && lbn < NDADDR &&
 280                     fragroundup(fs, blkoff(fs, length)) < fs->fs_bsize) {
 281                         bundirty(bp);
 282                         error = VOP_FSYNC(ovp, MNT_WAIT, 0);
 283                         if (error) {
 284                                 bdwrite(bp);
 285                                 return (error);
 286                         }
 287                 }
 288                 oip->i_size = length;
 289                 size = blksize(fs, oip, lbn);
 290 #if 0
 291                 /* remove - nvtruncbuf deals with this */
 292                 if (ovp->v_type != VDIR)
 293                         bzero((char *)bp->b_data + offset,
 294                             (uint)(size - offset));
 295 #endif
 296                 /* Kirk's code has reallocbuf(bp, size, 1) here */
 297                 allocbuf(bp, size);
 298                 if (bp->b_bufsize == fs->fs_bsize)
 299                         bp->b_flags |= B_CLUSTEROK;
 300                 if (aflags & B_SYNC)
 301                         bwrite(bp);
 302                 else
 303                         bawrite(bp);
 304         }
 305         /*
 306          * Calculate index into inode's block list of
 307          * last direct and indirect blocks (if any)
 308          * which we want to keep.  Lastblock is -1 when
 309          * the file is truncated to 0.
 310          */
 311         lastblock = lblkno(fs, length + fs->fs_bsize - 1) - 1;
 312         lastiblock[SINGLE] = lastblock - NDADDR;
 313         lastiblock[DOUBLE] = lastiblock[SINGLE] - NINDIR(fs);
 314         lastiblock[TRIPLE] = lastiblock[DOUBLE] - NINDIR(fs) * NINDIR(fs);
 315         nblocks = btodb(fs->fs_bsize);
 316
 317         /*
 318          * Update file and block pointers on disk before we start freeing
 319          * blocks.  If we crash before free'ing blocks below, the blocks
 320          * will be returned to the free list.  lastiblock values are also
 321          * normalized to -1 for calls to ffs_indirtrunc below.
 322          */
 323         bcopy((caddr_t)&oip->i_db[0], (caddr_t)oldblks, sizeof oldblks);
 324         for (level = TRIPLE; level >= SINGLE; level--)
 325                 if (lastiblock[level] < 0) {
 326                         oip->i_ib[level] = 0;
 327                         lastiblock[level] = -1;
 328                 }
 329         for (i = NDADDR - 1; i > lastblock; i--)
 330                 oip->i_db[i] = 0;
 331         oip->i_flag |= IN_CHANGE | IN_UPDATE;
 332         error = ffs_update(ovp, 1);
 333         if (error && allerror == 0)
 334                 allerror = error;
 335
 336         /*
 337          * Having written the new inode to disk, save its new configuration
 338          * and put back the old block pointers long enough to process them.
 339          * Note that we save the new block configuration so we can check it
 340          * when we are done.
 341          */
 342         bcopy((caddr_t)&oip->i_db[0], (caddr_t)newblks, sizeof newblks);
 343         bcopy((caddr_t)oldblks, (caddr_t)&oip->i_db[0], sizeof oldblks);
 344         oip->i_size = osize;
 345
 346         if (error && allerror == 0)
 347                 allerror = error;
 348
 349         /*
 350          * Indirect blocks first.
 351          */
 352         indir_lbn[SINGLE] = -NDADDR;
 353         indir_lbn[DOUBLE] = indir_lbn[SINGLE] - NINDIR(fs) - 1;
 354         indir_lbn[TRIPLE] = indir_lbn[DOUBLE] - NINDIR(fs) * NINDIR(fs) - 1;
 355         for (level = TRIPLE; level >= SINGLE; level--) {
 356                 bn = oip->i_ib[level];
 357                 if (bn != 0) {
 358                         error = ffs_indirtrunc(oip, indir_lbn[level],
 359                             fsbtodb(fs, bn), lastiblock[level], level, &count);
 360                         if (error)
 361                                 allerror = error;
 362                         blocksreleased += count;
 363                         if (lastiblock[level] < 0) {
 364                                 oip->i_ib[level] = 0;
 365                                 ffs_blkfree(oip, bn, fs->fs_bsize);
 366                                 blocksreleased += nblocks;
 367                         }
 368                 }
 369                 if (lastiblock[level] >= 0)
 370                         goto done;
 371         }
 372
 373         /*
 374          * All whole direct blocks or frags.
 375          */
 376         for (i = NDADDR - 1; i > lastblock; i--) {
 377                 long bsize;
 378
 379                 bn = oip->i_db[i];
 380                 if (bn == 0)
 381                         continue;
 382                 oip->i_db[i] = 0;
 383                 bsize = blksize(fs, oip, i);
 384                 ffs_blkfree(oip, bn, bsize);
 385                 blocksreleased += btodb(bsize);
 386         }
 387         if (lastblock < 0)
 388                 goto done;
 389
 390         /*
 391          * Finally, look for a change in size of the
 392          * last direct block; release any frags.
 393          */
 394         bn = oip->i_db[lastblock];
 395         if (bn != 0) {
 396                 long oldspace, newspace;
 397
 398                 /*
 399                  * Calculate amount of space we're giving
 400                  * back as old block size minus new block size.
 401                  */
 402                 oldspace = blksize(fs, oip, lastblock);
 403                 oip->i_size = length;
 404                 newspace = blksize(fs, oip, lastblock);
 405                 if (newspace == 0)
 406                         panic("ffs_truncate: newspace");
 407                 if (oldspace - newspace > 0) {
 408                         /*
 409                          * Block number of space to be free'd is
 410                          * the old block # plus the number of frags
 411                          * required for the storage we're keeping.
 412                          */
 413                         bn += numfrags(fs, newspace);
 414                         ffs_blkfree(oip, bn, oldspace - newspace);
 415                         blocksreleased += btodb(oldspace - newspace);
 416                 }
 417         }
 418 done:
 419 #ifdef DIAGNOSTIC
 420         for (level = SINGLE; level <= TRIPLE; level++)
 421                 if (newblks[NDADDR + level] != oip->i_ib[level])
 422                         panic("ffs_truncate1");
 423         for (i = 0; i < NDADDR; i++)
 424                 if (newblks[i] != oip->i_db[i])
 425                         panic("ffs_truncate2");
 426         if (length == 0 && !RB_EMPTY(&ovp->v_rbdirty_tree))
 427                 panic("ffs_truncate3");
 428 #endif /* DIAGNOSTIC */
 429         /*
 430          * Put back the real size.
 431          */
 432         oip->i_size = length;
 433         oip->i_blocks -= blocksreleased;
 434
 435         if (oip->i_blocks < 0)                  /* sanity */
 436                 oip->i_blocks = 0;
 437         oip->i_flag |= IN_CHANGE;
 438 #ifdef QUOTA
 439         (void) ufs_chkdq(oip, -blocksreleased, NOCRED, 0);
 440 #endif
 441         return (allerror);
 442 }
 443
 444 /*
 445  * Release blocks associated with the inode ip and stored in the indirect
 446  * block bn.  Blocks are free'd in LIFO order up to (but not including)
 447  * lastbn.  If level is greater than SINGLE, the block is an indirect block
 448  * and recursive calls to indirtrunc must be used to cleanse other indirect
 449  * blocks.
 450  *
 451  * NB: triple indirect blocks are untested.
 452  */
 453 static int
 454 ffs_indirtrunc(struct inode *ip, ufs_daddr_t lbn, ufs_daddr_t dbn,
 455                ufs_daddr_t lastbn, int level, long *countp)
 456 {
 457         int i;
 458         struct buf *bp;
 459         struct fs *fs = ip->i_fs;
 460         ufs_daddr_t *bap;
 461         struct vnode *vp;
 462         ufs_daddr_t *copy = NULL, nb, nlbn, last;
 463         long blkcount, factor;
 464         int nblocks, blocksreleased = 0;
 465         int error = 0, allerror = 0;
 466
 467         /*
 468          * Calculate index in current block of last
 469          * block to be kept.  -1 indicates the entire
 470          * block so we need not calculate the index.
 471          */
 472         factor = 1;
 473         for (i = SINGLE; i < level; i++)
 474                 factor *= NINDIR(fs);
 475         last = lastbn;
 476         if (lastbn > 0)
 477                 last /= factor;
 478         nblocks = btodb(fs->fs_bsize);
 479         /*
 480          * Get buffer of block pointers, zero those entries corresponding
 481          * to blocks to be free'd, and update on disk copy first.  Since
 482          * double(triple) indirect before single(double) indirect, calls
 483          * to bmap on these blocks will fail.  However, we already have
 484          * the on disk address, so we have to set the bio_offset field
 485          * explicitly instead of letting bread do everything for us.
 486          */
 487         vp = ITOV(ip);
 488         bp = getblk(vp, lblktodoff(fs, lbn), (int)fs->fs_bsize, 0, 0);
 489         if ((bp->b_flags & B_CACHE) == 0) {
 490                 bp->b_flags &= ~(B_ERROR|B_INVAL);
 491                 bp->b_cmd = BUF_CMD_READ;
 492                 if (bp->b_bcount > bp->b_bufsize)
 493                         panic("ffs_indirtrunc: bad buffer size");
 494                 /*
 495                  * BIO is bio2 which chains back to bio1.  We wait
 496                  * on bio1.
 497                  */
 498                 bp->b_bio2.bio_offset = dbtodoff(fs, dbn);
 499                 bp->b_bio1.bio_done = biodone_sync;
 500                 bp->b_bio1.bio_flags |= BIO_SYNC;
 501                 vfs_busy_pages(vp, bp);
 502                 /*
 503                  * Access the block device layer using the device vnode
 504                  * and the translated block number (bio2) instead of the
 505                  * file vnode (vp) and logical block number (bio1).
 506                  *
 507                  * Even though we are bypassing the vnode layer, we still
 508                  * want the vnode state to indicate that an I/O on its behalf
 509                  * is in progress.
 510                  */
 511                 bio_start_transaction(&bp->b_bio1, &vp->v_track_read);
 512                 vn_strategy(ip->i_devvp, &bp->b_bio2);
 513                 error = biowait(&bp->b_bio1, "biord");
 514         }
 515         if (error) {
 516                 brelse(bp);
 517                 *countp = 0;
 518                 return (error);
 519         }
 520
 521         bap = (ufs_daddr_t *)bp->b_data;
 522         if (lastbn != -1) {
 523                 copy = kmalloc(fs->fs_bsize, M_TEMP, M_WAITOK);
 524                 bcopy((caddr_t)bap, (caddr_t)copy, (uint)fs->fs_bsize);
 525                 bzero((caddr_t)&bap[last + 1],
 526                     (uint)(NINDIR(fs) - (last + 1)) * sizeof (ufs_daddr_t));
 527                 if (DOINGASYNC(vp)) {
 528                         bawrite(bp);
 529                 } else {
 530                         error = bwrite(bp);
 531                         if (error)
 532                                 allerror = error;
 533                 }
 534                 bap = copy;
 535         }
 536
 537         /*
 538          * Recursively free totally unused blocks.
 539          */
 540         for (i = NINDIR(fs) - 1, nlbn = lbn + 1 - i * factor; i > last;
 541             i--, nlbn += factor) {
 542                 nb = bap[i];
 543                 if (nb == 0)
 544                         continue;
 545                 if (level > SINGLE) {
 546                         if ((error = ffs_indirtrunc(ip, nlbn, fsbtodb(fs, nb),
 547                             (ufs_daddr_t)-1, level - 1, &blkcount)) != 0)
 548                                 allerror = error;
 549                         blocksreleased += blkcount;
 550                 }
 551                 ffs_blkfree(ip, nb, fs->fs_bsize);
 552                 blocksreleased += nblocks;
 553         }
 554
 555         /*
 556          * Recursively free last partial block.
 557          */
 558         if (level > SINGLE && lastbn >= 0) {
 559                 last = lastbn % factor;
 560                 nb = bap[i];
 561                 if (nb != 0) {
 562                         error = ffs_indirtrunc(ip, nlbn, fsbtodb(fs, nb),
 563                             last, level - 1, &blkcount);
 564                         if (error)
 565                                 allerror = error;
 566                         blocksreleased += blkcount;
 567                 }
 568         }
 569         if (copy != NULL) {
 570                 kfree(copy, M_TEMP);
 571         } else {
 572                 bp->b_flags |= B_INVAL | B_NOCACHE;
 573                 brelse(bp);
 574         }
 575
 576         *countp = blocksreleased;
 577         return (allerror);
 578 }