Home | History | Annotate | Line # | Download | only in ext2fs
      1 /*	$NetBSD: ext2fs_inode.c,v 1.91 2023/08/26 05:22:50 riastradh Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 1982, 1986, 1989, 1993
      5  *	The Regents of the University of California.  All rights reserved.
      6  *
      7  * Redistribution and use in source and binary forms, with or without
      8  * modification, are permitted provided that the following conditions
      9  * are met:
     10  * 1. Redistributions of source code must retain the above copyright
     11  *    notice, this list of conditions and the following disclaimer.
     12  * 2. Redistributions in binary form must reproduce the above copyright
     13  *    notice, this list of conditions and the following disclaimer in the
     14  *    documentation and/or other materials provided with the distribution.
     15  * 3. Neither the name of the University nor the names of its contributors
     16  *    may be used to endorse or promote products derived from this software
     17  *    without specific prior written permission.
     18  *
     19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     29  * SUCH DAMAGE.
     30  *
     31  *	@(#)ffs_inode.c	8.8 (Berkeley) 10/19/94
     32  * Modified for ext2fs by Manuel Bouyer.
     33  */
     34 
     35 /*
     36  * Copyright (c) 1997 Manuel Bouyer.
     37  *
     38  * Redistribution and use in source and binary forms, with or without
     39  * modification, are permitted provided that the following conditions
     40  * are met:
     41  * 1. Redistributions of source code must retain the above copyright
     42  *    notice, this list of conditions and the following disclaimer.
     43  * 2. Redistributions in binary form must reproduce the above copyright
     44  *    notice, this list of conditions and the following disclaimer in the
     45  *    documentation and/or other materials provided with the distribution.
     46  *
     47  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
     48  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
     49  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
     50  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
     51  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
     52  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     53  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     54  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     55  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
     56  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     57  *
     58  *	@(#)ffs_inode.c	8.8 (Berkeley) 10/19/94
     59  * Modified for ext2fs by Manuel Bouyer.
     60  */
     61 
     62 #include <sys/cdefs.h>
     63 __KERNEL_RCSID(0, "$NetBSD: ext2fs_inode.c,v 1.91 2023/08/26 05:22:50 riastradh Exp $");
     64 
     65 #include <sys/param.h>
     66 #include <sys/systm.h>
     67 #include <sys/mount.h>
     68 #include <sys/proc.h>
     69 #include <sys/file.h>
     70 #include <sys/buf.h>
     71 #include <sys/vnode.h>
     72 #include <sys/kernel.h>
     73 #include <sys/kmem.h>
     74 #include <sys/trace.h>
     75 #include <sys/resourcevar.h>
     76 #include <sys/kauth.h>
     77 
     78 #include <ufs/ufs/inode.h>
     79 #include <ufs/ufs/ufsmount.h>
     80 #include <ufs/ufs/ufs_extern.h>
     81 
     82 #include <ufs/ext2fs/ext2fs.h>
     83 #include <ufs/ext2fs/ext2fs_extern.h>
     84 
     85 static int ext2fs_indirtrunc(struct inode *, daddr_t, daddr_t,
     86 				  daddr_t, int, long *);
     87 
     88 /*
     89  * These are fortunately the same values; it is likely that there is
     90  * code that assumes they're equal. In any event, neither ought to
     91  * ever change because it's a property of the on-disk formats.
     92  */
     93 CTASSERT(EXT2FS_NDADDR == UFS_NDADDR);
     94 CTASSERT(EXT2FS_NIADDR == UFS_NIADDR);
     95 
     96 /*
     97  * Get the size of an inode.
     98  */
     99 uint64_t
    100 ext2fs_size(struct inode *ip)
    101 {
    102 	uint64_t size = ip->i_e2fs_size;
    103 
    104 	if ((ip->i_e2fs_mode & IFMT) == IFREG)
    105 		size |= (uint64_t)ip->i_din.e2fs_din->e2di_size_high << 32;
    106 	return size;
    107 }
    108 
    109 int
    110 ext2fs_setsize(struct inode *ip, uint64_t size)
    111 {
    112 	if ((ip->i_e2fs_mode & IFMT) == IFREG ||
    113 	    ip->i_e2fs_mode == 0) {
    114 		ip->i_din.e2fs_din->e2di_size_high = size >> 32;
    115 		if (size >= 0x80000000U) {
    116 			struct m_ext2fs *fs = ip->i_e2fs;
    117 
    118 			if (fs->e2fs.e2fs_rev <= E2FS_REV0) {
    119 				/* Linux automagically upgrades to REV1 here! */
    120 				return EFBIG;
    121 			}
    122 			if (!EXT2F_HAS_ROCOMPAT_FEATURE(fs,
    123 			    EXT2F_ROCOMPAT_LARGEFILE)) {
    124 				fs->e2fs.e2fs_features_rocompat |=
    125 				    EXT2F_ROCOMPAT_LARGEFILE;
    126 				fs->e2fs_fmod = 1;
    127 			}
    128 		}
    129 	} else if (size >= 0x80000000U)
    130 		return EFBIG;
    131 
    132 	ip->i_e2fs_size = size;
    133 
    134 	return 0;
    135 }
    136 
    137 uint64_t
    138 ext2fs_nblock(struct inode *ip)
    139 {
    140 	uint64_t nblock = ip->i_e2fs_nblock;
    141 	struct m_ext2fs * const fs = ip->i_e2fs;
    142 
    143 	if (EXT2F_HAS_ROCOMPAT_FEATURE(fs, EXT2F_ROCOMPAT_HUGE_FILE)) {
    144 		nblock |= (uint64_t)ip->i_e2fs_nblock_high << 32;
    145 
    146 		if ((ip->i_e2fs_flags & EXT2_HUGE_FILE)) {
    147 			nblock = EXT2_FSBTODB(fs, nblock);
    148 		}
    149 	}
    150 
    151 	return nblock;
    152 }
    153 
    154 int
    155 ext2fs_setnblock(struct inode *ip, uint64_t nblock)
    156 {
    157 	struct m_ext2fs * const fs = ip->i_e2fs;
    158 
    159 	if (nblock <= 0xffffffffULL) {
    160 		CLR(ip->i_e2fs_flags, EXT2_HUGE_FILE);
    161 		ip->i_e2fs_nblock = nblock;
    162 		return 0;
    163 	}
    164 
    165 	if (!EXT2F_HAS_ROCOMPAT_FEATURE(fs, EXT2F_ROCOMPAT_HUGE_FILE))
    166 		return EFBIG;
    167 
    168 	if (nblock <= 0xffffffffffffULL) {
    169 		CLR(ip->i_e2fs_flags, EXT2_HUGE_FILE);
    170 		ip->i_e2fs_nblock = nblock & 0xffffffff;
    171 		ip->i_e2fs_nblock_high = (nblock >> 32) & 0xffff;
    172 		return 0;
    173 	}
    174 
    175 	if (EXT2_DBTOFSB(fs, nblock) <= 0xffffffffffffULL) {
    176 		SET(ip->i_e2fs_flags, EXT2_HUGE_FILE);
    177 		ip->i_e2fs_nblock = EXT2_DBTOFSB(fs, nblock) & 0xffffffff;
    178 		ip->i_e2fs_nblock_high = (EXT2_DBTOFSB(fs, nblock) >> 32) & 0xffff;
    179 		return 0;
    180 	}
    181 
    182 	return EFBIG;
    183 }
    184 
    185 /*
    186  * Last reference to an inode.  If necessary, write or delete it.
    187  */
    188 int
    189 ext2fs_inactive(void *v)
    190 {
    191 	struct vop_inactive_v2_args /* {
    192 		struct vnode *a_vp;
    193 		bool *a_recycle;
    194 	} */ *ap = v;
    195 	struct vnode *vp = ap->a_vp;
    196 	struct inode *ip = VTOI(vp);
    197 	int error = 0;
    198 
    199 	/* Get rid of inodes related to stale file handles. */
    200 	if (ip->i_e2fs_mode == 0 || ip->i_e2fs_dtime != 0)
    201 		goto out;
    202 
    203 	error = 0;
    204 	if (ip->i_e2fs_nlink == 0 && (vp->v_mount->mnt_flag & MNT_RDONLY) == 0) {
    205 		/* Defer final inode free and update to reclaim.*/
    206 		if (ext2fs_size(ip) != 0) {
    207 			error = ext2fs_truncate(vp, (off_t)0, 0, NOCRED);
    208 		}
    209 		ip->i_e2fs_dtime = time_second;
    210 		ip->i_flag |= IN_CHANGE | IN_UPDATE;
    211 		ip->i_omode = 1;
    212 	}
    213 	if (ip->i_flag & (IN_CHANGE | IN_UPDATE | IN_MODIFIED)) {
    214 		ext2fs_update(vp, NULL, NULL, 0);
    215 	}
    216 out:
    217 	/*
    218 	 * If we are done with the inode, reclaim it
    219 	 * so that it can be reused immediately.
    220 	 */
    221 	*ap->a_recycle = (ip->i_e2fs_dtime != 0);
    222 
    223 	return error;
    224 }
    225 
    226 
    227 /*
    228  * Update the access, modified, and inode change times as specified by the
    229  * IACCESS, IUPDATE, and ICHANGE flags respectively. The IMODIFIED flag is
    230  * used to specify that the inode needs to be updated but that the times have
    231  * already been set. The access and modified times are taken from the second
    232  * and third parameters; the inode change time is always taken from the current
    233  * time. If UPDATE_WAIT or UPDATE_DIROP is set, then wait for the disk
    234  * write of the inode to complete.
    235  */
    236 int
    237 ext2fs_update(struct vnode *vp, const struct timespec *acc,
    238     const struct timespec *mod, int updflags)
    239 {
    240 	struct m_ext2fs *fs;
    241 	struct buf *bp;
    242 	struct inode *ip;
    243 	int error;
    244 	void *cp;
    245 	int flags;
    246 
    247 	if (vp->v_mount->mnt_flag & MNT_RDONLY)
    248 		return 0;
    249 	ip = VTOI(vp);
    250 	EXT2FS_ITIMES(ip, acc, mod, NULL);
    251 	if (updflags & UPDATE_CLOSE)
    252 		flags = ip->i_flag & (IN_MODIFIED | IN_ACCESSED);
    253 	else
    254 		flags = ip->i_flag & IN_MODIFIED;
    255 	if (flags == 0)
    256 		return 0;
    257 	fs = ip->i_e2fs;
    258 
    259 	error = bread(ip->i_devvp,
    260 			  EXT2_FSBTODB(fs, ino_to_fsba(fs, ip->i_number)),
    261 			  (int)fs->e2fs_bsize, B_MODIFY, &bp);
    262 	if (error) {
    263 		return error;
    264 	}
    265 	ip->i_flag &= ~(IN_MODIFIED | IN_ACCESSED);
    266 	cp = (char *)bp->b_data +
    267 	    (ino_to_fsbo(fs, ip->i_number) * EXT2_DINODE_SIZE(fs));
    268 	e2fs_isave(ip->i_din.e2fs_din, (struct ext2fs_dinode *)cp, EXT2_DINODE_SIZE(fs));
    269 	if ((updflags & (UPDATE_WAIT|UPDATE_DIROP)) != 0 &&
    270 	    (flags & IN_MODIFIED) != 0 &&
    271 	    (vp->v_mount->mnt_flag & MNT_ASYNC) == 0)
    272 		return bwrite(bp);
    273 	else {
    274 		bdwrite(bp);
    275 		return 0;
    276 	}
    277 }
    278 
    279 #define	SINGLE	0	/* index of single indirect block */
    280 #define	DOUBLE	1	/* index of double indirect block */
    281 #define	TRIPLE	2	/* index of triple indirect block */
    282 /*
    283  * Truncate the inode oip to at most length size, freeing the
    284  * disk blocks.
    285  */
    286 int
    287 ext2fs_truncate(struct vnode *ovp, off_t length, int ioflag,
    288     kauth_cred_t cred)
    289 {
    290 	daddr_t lastblock;
    291 	struct inode *oip = VTOI(ovp);
    292 	daddr_t bn, lastiblock[EXT2FS_NIADDR], indir_lbn[EXT2FS_NIADDR];
    293 	/* XXX ondisk32 */
    294 	int32_t oldblks[EXT2FS_NDADDR + EXT2FS_NIADDR], newblks[EXT2FS_NDADDR + EXT2FS_NIADDR];
    295 	struct m_ext2fs *fs;
    296 	int offset, size, level;
    297 	long count, blocksreleased = 0;
    298 	int i, nblocks;
    299 	int error, allerror = 0;
    300 	off_t osize;
    301 	int sync;
    302 	struct ufsmount *ump = oip->i_ump;
    303 
    304 	if (ovp->v_type == VCHR || ovp->v_type == VBLK ||
    305 	    ovp->v_type == VFIFO || ovp->v_type == VSOCK) {
    306 		return 0;
    307 	}
    308 
    309 	if (length < 0)
    310 		return EINVAL;
    311 
    312 	if (ovp->v_type == VLNK &&
    313 	    (ext2fs_size(oip) < ump->um_maxsymlinklen ||
    314 	     (ump->um_maxsymlinklen == 0 && ext2fs_nblock(oip) == 0))) {
    315 		KDASSERT(length == 0);
    316 		memset((char *)&oip->i_din.e2fs_din->e2di_shortlink, 0,
    317 			(u_int)ext2fs_size(oip));
    318 		(void)ext2fs_setsize(oip, 0);
    319 		goto update;
    320 	}
    321 	if (ext2fs_size(oip) == length) {
    322 		/* still do a uvm_vnp_setsize() as writesize may be larger */
    323 		uvm_vnp_setsize(ovp, length);
    324 		goto update;
    325 	}
    326 	fs = oip->i_e2fs;
    327 	if (length > ump->um_maxfilesize)
    328 		return EFBIG;
    329 
    330 	osize = ext2fs_size(oip);
    331 
    332 	/*
    333 	 * Lengthen the size of the file. We must ensure that the
    334 	 * last byte of the file is allocated. Since the smallest
    335 	 * value of osize is 0, length will be at least 1.
    336 	 */
    337 	if (osize < length) {
    338 		uvm_vnp_setwritesize(ovp, length);
    339 		error = ufs_balloc_range(ovp, length - 1, 1, cred,
    340 		    ioflag & IO_SYNC ? B_SYNC : 0);
    341 		if (error) {
    342 			(void) ext2fs_truncate(ovp, osize, ioflag & IO_SYNC,
    343 			    cred);
    344 			return error;
    345 		}
    346 		uvm_vnp_setsize(ovp, length);
    347 		KASSERT(error  || ovp->v_size == ext2fs_size(oip));
    348 		goto update;
    349 	}
    350 	/*
    351 	 * Shorten the size of the file. If the file is not being
    352 	 * truncated to a block boundary, the contents of the
    353 	 * partial block following the end of the file must be
    354 	 * zero'ed in case it ever become accessible again because
    355 	 * of subsequent file growth.
    356 	 */
    357 	offset = ext2_blkoff(fs, length);
    358 	if (offset != 0) {
    359 		size = fs->e2fs_bsize;
    360 
    361 		/* XXXUBC we should handle more than just VREG */
    362 		ubc_zerorange(&ovp->v_uobj, length, size - offset,
    363 		    UBC_VNODE_FLAGS(ovp));
    364 	}
    365 	(void)ext2fs_setsize(oip, length);
    366 	uvm_vnp_setsize(ovp, length);
    367 	/*
    368 	 * Calculate index into inode's block list of
    369 	 * last direct and indirect blocks (if any)
    370 	 * which we want to keep.  Lastblock is -1 when
    371 	 * the file is truncated to 0.
    372 	 */
    373 	lastblock = ext2_lblkno(fs, length + fs->e2fs_bsize - 1) - 1;
    374 	lastiblock[SINGLE] = lastblock - EXT2FS_NDADDR;
    375 	lastiblock[DOUBLE] = lastiblock[SINGLE] - EXT2_NINDIR(fs);
    376 	lastiblock[TRIPLE] = lastiblock[DOUBLE] - EXT2_NINDIR(fs) * EXT2_NINDIR(fs);
    377 	nblocks = btodb(fs->e2fs_bsize);
    378 	/*
    379 	 * Update file and block pointers on disk before we start freeing
    380 	 * blocks.  If we crash before free'ing blocks below, the blocks
    381 	 * will be returned to the free list.  lastiblock values are also
    382 	 * normalized to -1 for calls to ext2fs_indirtrunc below.
    383 	 */
    384 	memcpy((void *)oldblks, (void *)&oip->i_e2fs_blocks[0], sizeof oldblks);
    385 	sync = 0;
    386 	for (level = TRIPLE; level >= SINGLE; level--) {
    387 		if (lastiblock[level] < 0 && oldblks[EXT2FS_NDADDR + level] != 0) {
    388 			sync = 1;
    389 			oip->i_e2fs_blocks[EXT2FS_NDADDR + level] = 0;
    390 			lastiblock[level] = -1;
    391 		}
    392 	}
    393 	for (i = 0; i < EXT2FS_NDADDR; i++) {
    394 		if (i > lastblock && oldblks[i] != 0) {
    395 			sync = 1;
    396 			oip->i_e2fs_blocks[i] = 0;
    397 		}
    398 	}
    399 	oip->i_flag |= IN_CHANGE | IN_UPDATE;
    400 	if (sync) {
    401 		error = ext2fs_update(ovp, NULL, NULL, UPDATE_WAIT);
    402 		if (error && !allerror)
    403 			allerror = error;
    404 	}
    405 
    406 	/*
    407 	 * Having written the new inode to disk, save its new configuration
    408 	 * and put back the old block pointers long enough to process them.
    409 	 * Note that we save the new block configuration so we can check it
    410 	 * when we are done.
    411 	 */
    412 	memcpy((void *)newblks, (void *)&oip->i_e2fs_blocks[0], sizeof newblks);
    413 	memcpy((void *)&oip->i_e2fs_blocks[0], (void *)oldblks, sizeof oldblks);
    414 
    415 	(void)ext2fs_setsize(oip, osize);
    416 	error = vtruncbuf(ovp, lastblock + 1, 0, 0);
    417 	if (error && !allerror)
    418 		allerror = error;
    419 
    420 	/*
    421 	 * Indirect blocks first.
    422 	 */
    423 	indir_lbn[SINGLE] = -EXT2FS_NDADDR;
    424 	indir_lbn[DOUBLE] = indir_lbn[SINGLE] - EXT2_NINDIR(fs) -1;
    425 	indir_lbn[TRIPLE] = indir_lbn[DOUBLE] - EXT2_NINDIR(fs) * EXT2_NINDIR(fs) - 1;
    426 	for (level = TRIPLE; level >= SINGLE; level--) {
    427 		/* XXX ondisk32 */
    428 		bn = fs2h32(oip->i_e2fs_blocks[EXT2FS_NDADDR + level]);
    429 		if (bn != 0) {
    430 			error = ext2fs_indirtrunc(oip, indir_lbn[level],
    431 			    EXT2_FSBTODB(fs, bn), lastiblock[level], level, &count);
    432 			if (error)
    433 				allerror = error;
    434 			blocksreleased += count;
    435 			if (lastiblock[level] < 0) {
    436 				oip->i_e2fs_blocks[EXT2FS_NDADDR + level] = 0;
    437 				ext2fs_blkfree(oip, bn);
    438 				blocksreleased += nblocks;
    439 			}
    440 		}
    441 		if (lastiblock[level] >= 0)
    442 			goto done;
    443 	}
    444 
    445 	/*
    446 	 * All whole direct blocks or frags.
    447 	 */
    448 	for (i = EXT2FS_NDADDR - 1; i > lastblock; i--) {
    449 		/* XXX ondisk32 */
    450 		bn = fs2h32(oip->i_e2fs_blocks[i]);
    451 		if (bn == 0)
    452 			continue;
    453 		oip->i_e2fs_blocks[i] = 0;
    454 		ext2fs_blkfree(oip, bn);
    455 		blocksreleased += btodb(fs->e2fs_bsize);
    456 	}
    457 
    458 done:
    459 #ifdef DIAGNOSTIC
    460 	for (level = SINGLE; level <= TRIPLE; level++)
    461 		if (newblks[EXT2FS_NDADDR + level] !=
    462 		    oip->i_e2fs_blocks[EXT2FS_NDADDR + level])
    463 			panic("ext2fs_truncate1");
    464 	for (i = 0; i < EXT2FS_NDADDR; i++)
    465 		if (newblks[i] != oip->i_e2fs_blocks[i])
    466 			panic("ext2fs_truncate2");
    467 	if (length == 0 &&
    468 	    (!LIST_EMPTY(&ovp->v_cleanblkhd) ||
    469 	     !LIST_EMPTY(&ovp->v_dirtyblkhd)))
    470 		panic("ext2fs_truncate3");
    471 #endif /* DIAGNOSTIC */
    472 	/*
    473 	 * Put back the real size.
    474 	 */
    475 	(void)ext2fs_setsize(oip, length);
    476 	error = ext2fs_setnblock(oip, ext2fs_nblock(oip) - blocksreleased);
    477 	if (error != 0)
    478 		allerror = error;
    479 	oip->i_flag |= IN_CHANGE;
    480 	KASSERT(ovp->v_type != VREG || ovp->v_size == ext2fs_size(oip));
    481 	return allerror;
    482 update:
    483 	oip->i_flag |= IN_CHANGE | IN_UPDATE;
    484 	return ext2fs_update(ovp, NULL, NULL, 0);
    485 }
    486 
    487 /*
    488  * Release blocks associated with the inode ip and stored in the indirect
    489  * block bn.  Blocks are free'd in LIFO order up to (but not including)
    490  * lastbn.  If level is greater than SINGLE, the block is an indirect block
    491  * and recursive calls to indirtrunc must be used to cleanse other indirect
    492  * blocks.
    493  *
    494  * NB: triple indirect blocks are untested.
    495  */
    496 static int
    497 ext2fs_indirtrunc(struct inode *ip, daddr_t lbn, daddr_t dbn, daddr_t lastbn,
    498 		int level, long *countp)
    499 {
    500 	int i;
    501 	struct buf *bp;
    502 	struct m_ext2fs *fs = ip->i_e2fs;
    503 	int32_t *bap;	/* XXX ondisk32 */
    504 	struct vnode *vp;
    505 	daddr_t nb, nlbn, last;
    506 	int32_t *copy = NULL;	/* XXX ondisk32 */
    507 	long blkcount, factor;
    508 	int nblocks, blocksreleased = 0;
    509 	int error = 0, allerror = 0;
    510 
    511 	/*
    512 	 * Calculate index in current block of last
    513 	 * block to be kept.  -1 indicates the entire
    514 	 * block so we need not calculate the index.
    515 	 */
    516 	factor = 1;
    517 	for (i = SINGLE; i < level; i++)
    518 		factor *= EXT2_NINDIR(fs);
    519 	last = lastbn;
    520 	if (lastbn > 0)
    521 		last /= factor;
    522 	nblocks = btodb(fs->e2fs_bsize);
    523 	/*
    524 	 * Get buffer of block pointers, zero those entries corresponding
    525 	 * to blocks to be free'd, and update on disk copy first.  Since
    526 	 * double(triple) indirect before single(double) indirect, calls
    527 	 * to bmap on these blocks will fail.  However, we already have
    528 	 * the on disk address, so we have to set the b_blkno field
    529 	 * explicitly instead of letting bread do everything for us.
    530 	 */
    531 	vp = ITOV(ip);
    532 	bp = getblk(vp, lbn, (int)fs->e2fs_bsize, 0, 0);
    533 	if (bp->b_oflags & (BO_DONE | BO_DELWRI)) {
    534 		/* Braces must be here in case trace evaluates to nothing. */
    535 		trace(TR_BREADHIT, pack(vp, fs->e2fs_bsize), lbn);
    536 	} else {
    537 		trace(TR_BREADMISS, pack(vp, fs->e2fs_bsize), lbn);
    538 		curlwp->l_ru.ru_inblock++;	/* pay for read */
    539 		bp->b_flags |= B_READ;
    540 		if (bp->b_bcount > bp->b_bufsize)
    541 			panic("ext2fs_indirtrunc: bad buffer size");
    542 		bp->b_blkno = dbn;
    543 		VOP_STRATEGY(vp, bp);
    544 		error = biowait(bp);
    545 	}
    546 	if (error) {
    547 		brelse(bp, 0);
    548 		*countp = 0;
    549 		return error;
    550 	}
    551 
    552 	bap = (int32_t *)bp->b_data;	/* XXX ondisk32 */
    553 	if (lastbn >= 0) {
    554 		/* XXX ondisk32 */
    555 		copy = kmem_alloc(fs->e2fs_bsize, KM_SLEEP);
    556 		memcpy((void *)copy, (void *)bap, (u_int)fs->e2fs_bsize);
    557 		memset((void *)&bap[last + 1], 0,
    558 			(u_int)(EXT2_NINDIR(fs) - (last + 1)) * sizeof (uint32_t));
    559 		error = bwrite(bp);
    560 		if (error)
    561 			allerror = error;
    562 		bap = copy;
    563 	}
    564 
    565 	/*
    566 	 * Recursively free totally unused blocks.
    567 	 */
    568 	for (i = EXT2_NINDIR(fs) - 1,
    569 		nlbn = lbn + 1 - i * factor; i > last;
    570 		i--, nlbn += factor) {
    571 		/* XXX ondisk32 */
    572 		nb = fs2h32(bap[i]);
    573 		if (nb == 0)
    574 			continue;
    575 		if (level > SINGLE) {
    576 			error = ext2fs_indirtrunc(ip, nlbn, EXT2_FSBTODB(fs, nb),
    577 						   (daddr_t)-1, level - 1,
    578 						   &blkcount);
    579 			if (error)
    580 				allerror = error;
    581 			blocksreleased += blkcount;
    582 		}
    583 		ext2fs_blkfree(ip, nb);
    584 		blocksreleased += nblocks;
    585 	}
    586 
    587 	/*
    588 	 * Recursively free last partial block.
    589 	 */
    590 	if (level > SINGLE && lastbn >= 0) {
    591 		last = lastbn % factor;
    592 		/* XXX ondisk32 */
    593 		nb = fs2h32(bap[i]);
    594 		if (nb != 0) {
    595 			error = ext2fs_indirtrunc(ip, nlbn, EXT2_FSBTODB(fs, nb),
    596 						   last, level - 1, &blkcount);
    597 			if (error)
    598 				allerror = error;
    599 			blocksreleased += blkcount;
    600 		}
    601 	}
    602 
    603 	if (copy != NULL) {
    604 		kmem_free(copy, fs->e2fs_bsize);
    605 	} else {
    606 		brelse(bp, BC_INVAL);
    607 	}
    608 
    609 	*countp = blocksreleased;
    610 	return allerror;
    611 }
    612