/* VOP_BWRITE ULFS_NIADDR+2 times */
int
lfs_balloc(struct vnode *vp, off_t startoffset, int iosize, kauth_cred_t cred,
    int flags, struct buf **bpp)
{
	int offset;
	daddr_t daddr, idaddr;
	struct buf *ibp, *bp;
	struct inode *ip;
	struct lfs *fs;
	struct indir indirs[ULFS_NIADDR+2], *idp;
	daddr_t	lbn, lastblock;
	int bcount;
	int error, frags, i, nsize, osize, num;

	ip = VTOI(vp);
	fs = ip->i_lfs;
	offset = lfs_blkoff(fs, startoffset);
	KASSERT(iosize <= lfs_sb_getbsize(fs));
	lbn = lfs_lblkno(fs, startoffset);
	/* (void)lfs_check(vp, lbn, 0); */

	ASSERT_MAYBE_SEGLOCK(fs);

	/*
	 * Three cases: it's a block beyond the end of file, it's a block in
	 * the file that may or may not have been assigned a disk address or
	 * we're writing an entire block.
	 *
	 * Note, if the daddr is UNWRITTEN, the block already exists in
	 * the cache (it was read or written earlier).	If so, make sure
	 * we don't count it as a new block or zero out its contents. If
	 * it did not, make sure we allocate any necessary indirect
	 * blocks.
	 *
	 * If we are writing a block beyond the end of the file, we need to
	 * check if the old last block was a fragment.	If it was, we need
	 * to rewrite it.
	 */

	if (bpp)
		*bpp = NULL;

	/* Check for block beyond end of file and fragment extension needed. */
	lastblock = lfs_lblkno(fs, ip->i_size);
	if (lastblock < ULFS_NDADDR && lastblock < lbn) {
		osize = lfs_blksize(fs, ip, lastblock);
		if (osize < lfs_sb_getbsize(fs) && osize > 0) {
			if ((error = lfs_fragextend(vp, osize, lfs_sb_getbsize(fs),
						    lastblock,
						    (bpp ? &bp : NULL), cred)))
				return (error);
			ip->i_size = (lastblock + 1) * lfs_sb_getbsize(fs);
			lfs_dino_setsize(fs, ip->i_din, ip->i_size);
			uvm_vnp_setsize(vp, ip->i_size);
			ip->i_flag |= IN_CHANGE | IN_UPDATE;
			if (bpp)
				(void) VOP_BWRITE(bp->b_vp, bp);
		}
	}

	/*
	 * If the block we are writing is a direct block, it's the last
	 * block in the file, and offset + iosize is less than a full
	 * block, we can write one or more fragments.  There are two cases:
	 * the block is brand new and we should allocate it the correct
	 * size or it already exists and contains some fragments and
	 * may need to extend it.
	 */
	if (lbn < ULFS_NDADDR && lfs_lblkno(fs, ip->i_size) <= lbn) {
		osize = lfs_blksize(fs, ip, lbn);
		nsize = lfs_fragroundup(fs, offset + iosize);
		if (lfs_lblktosize(fs, lbn) >= ip->i_size) {
			/* Brand new block or fragment */
			frags = lfs_numfrags(fs, nsize);
			if (!ISSPACE(fs, frags, cred))
				return ENOSPC;
			if (bpp) {
				*bpp = bp = getblk(vp, lbn, nsize, 0, 0);
				bp->b_blkno = UNWRITTEN;
				if (flags & B_CLRBUF)
					clrbuf(bp);
			}
			ip->i_lfs_effnblks += frags;
			mutex_enter(&lfs_lock);
			lfs_sb_subbfree(fs, frags);
			mutex_exit(&lfs_lock);
			lfs_dino_setdb(fs, ip->i_din, lbn, UNWRITTEN);
		} else {
			if (nsize <= osize) {
				/* No need to extend */
				if (bpp && (error = bread(vp, lbn, osize,
				    0, &bp)))
					return error;
			} else {
				/* Extend existing block */
				if ((error =
				     lfs_fragextend(vp, osize, nsize, lbn,
						    (bpp ? &bp : NULL), cred)))
					return error;
			}
			if (bpp)
				*bpp = bp;
		}
		return 0;
	}

	error = ulfs_bmaparray(vp, lbn, &daddr, &indirs[0], &num, NULL, NULL);
	if (error)
		return (error);

	KASSERT(daddr <= LFS_MAX_DADDR(fs));

	/*
	 * Do byte accounting all at once, so we can gracefully fail *before*
	 * we start assigning blocks.
	 */
	frags = fs->um_seqinc;
	bcount = 0;
	if (daddr == UNASSIGNED) {
		bcount = frags;
	}
	for (i = 1; i < num; ++i) {
		if (!indirs[i].in_exists) {
			bcount += frags;
		}
	}
	if (ISSPACE(fs, bcount, cred)) {
		mutex_enter(&lfs_lock);
		lfs_sb_subbfree(fs, bcount);
		mutex_exit(&lfs_lock);
		ip->i_lfs_effnblks += bcount;
	} else {
		return ENOSPC;
	}

	if (daddr == UNASSIGNED) {
		if (num > 0 && lfs_dino_getib(fs, ip->i_din, indirs[0].in_off) == 0) {
			lfs_dino_setib(fs, ip->i_din, indirs[0].in_off, UNWRITTEN);
		}

		/*
		 * Create new indirect blocks if necessary
		 */
		if (num > 1) {
			idaddr = lfs_dino_getib(fs, ip->i_din, indirs[0].in_off);
			for (i = 1; i < num; ++i) {
				ibp = getblk(vp, indirs[i].in_lbn,
				    lfs_sb_getbsize(fs), 0,0);
				if (!indirs[i].in_exists) {
					clrbuf(ibp);
					ibp->b_blkno = UNWRITTEN;
				} else if (!(ibp->b_oflags & (BO_DELWRI | BO_DONE))) {
					ibp->b_blkno = LFS_FSBTODB(fs, idaddr);
					ibp->b_flags |= B_READ;
					VOP_STRATEGY(vp, ibp);
					biowait(ibp);
				}
				/*
				 * This block exists, but the next one may not.
				 * If that is the case mark it UNWRITTEN to keep
				 * the accounting straight.
				 */
				/* XXX ondisk32 */
				if (((int32_t *)ibp->b_data)[indirs[i].in_off] == 0)
					((int32_t *)ibp->b_data)[indirs[i].in_off] =
						UNWRITTEN;
				/* XXX ondisk32 */
				idaddr = ((int32_t *)ibp->b_data)[indirs[i].in_off];
#ifdef DEBUG
				if (vp == fs->lfs_ivnode) {
					LFS_ENTER_LOG("balloc", __FILE__,
						__LINE__, indirs[i].in_lbn,
						ibp->b_flags, curproc->p_pid);
				}
#endif
				if ((error = VOP_BWRITE(ibp->b_vp, ibp)))
					return error;
			}
		}
	}


	/*
	 * Get the existing block from the cache, if requested.
	 */
	if (bpp)
		*bpp = bp = getblk(vp, lbn, lfs_blksize(fs, ip, lbn), 0, 0);

	/*
	 * Do accounting on blocks that represent pages.
	 */
	if (!bpp)
		lfs_register_block(vp, lbn);

	/*
	 * The block we are writing may be a brand new block
	 * in which case we need to do accounting.
	 *
	 * We can tell a truly new block because ulfs_bmaparray will say
	 * it is UNASSIGNED.  Once we allocate it we will assign it the
	 * disk address UNWRITTEN.
	 */
	if (daddr == UNASSIGNED) {
		if (bpp) {
			if (flags & B_CLRBUF)
				clrbuf(bp);

			/* Note the new address */
			bp->b_blkno = UNWRITTEN;
		}

		switch (num) {
		    case 0:
			lfs_dino_setdb(fs, ip->i_din, lbn, UNWRITTEN);
			break;
		    case 1:
			lfs_dino_setib(fs, ip->i_din, indirs[0].in_off, UNWRITTEN);
			break;
		    default:
			idp = &indirs[num - 1];
			if (bread(vp, idp->in_lbn, lfs_sb_getbsize(fs),
				  B_MODIFY, &ibp))
				panic("lfs_balloc: bread bno %lld",
				    (long long)idp->in_lbn);
			/* XXX ondisk32 */
			((int32_t *)ibp->b_data)[idp->in_off] = UNWRITTEN;
#ifdef DEBUG
			if (vp == fs->lfs_ivnode) {
				LFS_ENTER_LOG("balloc", __FILE__,
					__LINE__, idp->in_lbn,
					ibp->b_flags, curproc->p_pid);
			}
#endif
			VOP_BWRITE(ibp->b_vp, ibp);
		}
	} else if (bpp && !(bp->b_oflags & (BO_DONE|BO_DELWRI))) {
		/*
		 * Not a brand new block, also not in the cache;
		 * read it in from disk.
		 */
		if (iosize == lfs_sb_getbsize(fs))
			/* Optimization: I/O is unnecessary. */
			bp->b_blkno = daddr;
		else {
			/*
			 * We need to read the block to preserve the
			 * existing bytes.
			 */
			bp->b_blkno = daddr;
			bp->b_flags |= B_READ;
			VOP_STRATEGY(vp, bp);
			return (biowait(bp));
		}
	}

	return (0);
}
예제 #2
0
int
lfs_truncate(struct vnode *ovp, off_t length, int ioflag, kauth_cred_t cred)
{
	daddr_t lastblock;
	struct inode *oip = VTOI(ovp);
	daddr_t bn, lbn, lastiblock[ULFS_NIADDR], indir_lbn[ULFS_NIADDR];
	/* XXX ondisk32 */
	int32_t newblks[ULFS_NDADDR + ULFS_NIADDR];
	struct lfs *fs;
	struct buf *bp;
	int offset, size, level;
	daddr_t count, rcount;
	daddr_t blocksreleased = 0, real_released = 0;
	int i, nblocks;
	int aflags, error, allerror = 0;
	off_t osize;
	long lastseg;
	size_t bc;
	int obufsize, odb;
	int usepc;

	if (ovp->v_type == VCHR || ovp->v_type == VBLK ||
	    ovp->v_type == VFIFO || ovp->v_type == VSOCK) {
		KASSERT(oip->i_size == 0);
		return 0;
	}

	if (length < 0)
		return (EINVAL);

	/*
	 * Just return and not update modification times.
	 */
	if (oip->i_size == length) {
		/* still do a uvm_vnp_setsize() as writesize may be larger */
		uvm_vnp_setsize(ovp, length);
		return (0);
	}

	fs = oip->i_lfs;

	if (ovp->v_type == VLNK &&
	    (oip->i_size < fs->um_maxsymlinklen ||
	     (fs->um_maxsymlinklen == 0 &&
	      oip->i_ffs1_blocks == 0))) {
#ifdef DIAGNOSTIC
		if (length != 0)
			panic("lfs_truncate: partial truncate of symlink");
#endif
		memset((char *)SHORTLINK(oip), 0, (u_int)oip->i_size);
		oip->i_size = oip->i_ffs1_size = 0;
		oip->i_flag |= IN_CHANGE | IN_UPDATE;
		return (lfs_update(ovp, NULL, NULL, 0));
	}
	if (oip->i_size == length) {
		oip->i_flag |= IN_CHANGE | IN_UPDATE;
		return (lfs_update(ovp, NULL, NULL, 0));
	}
	lfs_imtime(fs);
	osize = oip->i_size;
	usepc = (ovp->v_type == VREG && ovp != fs->lfs_ivnode);

	ASSERT_NO_SEGLOCK(fs);
	/*
	 * Lengthen the size of the file. We must ensure that the
	 * last byte of the file is allocated. Since the smallest
	 * value of osize is 0, length will be at least 1.
	 */
	if (osize < length) {
		if (length > fs->um_maxfilesize)
			return (EFBIG);
		aflags = B_CLRBUF;
		if (ioflag & IO_SYNC)
			aflags |= B_SYNC;
		if (usepc) {
			if (lfs_lblkno(fs, osize) < ULFS_NDADDR &&
			    lfs_lblkno(fs, osize) != lfs_lblkno(fs, length) &&
			    lfs_blkroundup(fs, osize) != osize) {
				off_t eob;

				eob = lfs_blkroundup(fs, osize);
				uvm_vnp_setwritesize(ovp, eob);
				error = ulfs_balloc_range(ovp, osize,
				    eob - osize, cred, aflags);
				if (error) {
					(void) lfs_truncate(ovp, osize,
						    ioflag & IO_SYNC, cred);
					return error;
				}
				if (ioflag & IO_SYNC) {
					mutex_enter(ovp->v_interlock);
					VOP_PUTPAGES(ovp,
					    trunc_page(osize & lfs_sb_getbmask(fs)),
					    round_page(eob),
					    PGO_CLEANIT | PGO_SYNCIO);
				}
			}
			uvm_vnp_setwritesize(ovp, length);
			error = ulfs_balloc_range(ovp, length - 1, 1, cred,
						 aflags);
			if (error) {
				(void) lfs_truncate(ovp, osize,
						    ioflag & IO_SYNC, cred);
				return error;
			}
			uvm_vnp_setsize(ovp, length);
			oip->i_flag |= IN_CHANGE | IN_UPDATE;
			KASSERT(ovp->v_size == oip->i_size);
			oip->i_lfs_hiblk = lfs_lblkno(fs, oip->i_size + lfs_sb_getbsize(fs) - 1) - 1;
			return (lfs_update(ovp, NULL, NULL, 0));
		} else {
			error = lfs_reserve(fs, ovp, NULL,
			    lfs_btofsb(fs, (ULFS_NIADDR + 2) << lfs_sb_getbshift(fs)));
			if (error)
				return (error);
			error = lfs_balloc(ovp, length - 1, 1, cred,
					   aflags, &bp);
			lfs_reserve(fs, ovp, NULL,
			    -lfs_btofsb(fs, (ULFS_NIADDR + 2) << lfs_sb_getbshift(fs)));
			if (error)
				return (error);
			oip->i_ffs1_size = oip->i_size = length;
			uvm_vnp_setsize(ovp, length);
			(void) VOP_BWRITE(bp->b_vp, bp);
			oip->i_flag |= IN_CHANGE | IN_UPDATE;
			oip->i_lfs_hiblk = lfs_lblkno(fs, oip->i_size + lfs_sb_getbsize(fs) - 1) - 1;
			return (lfs_update(ovp, NULL, NULL, 0));
		}
	}

	if ((error = lfs_reserve(fs, ovp, NULL,
	    lfs_btofsb(fs, (2 * ULFS_NIADDR + 3) << lfs_sb_getbshift(fs)))) != 0)
		return (error);

	/*
	 * Shorten the size of the file. If the file is not being
	 * truncated to a block boundary, the contents of the
	 * partial block following the end of the file must be
	 * zero'ed in case it ever becomes accessible again because
	 * of subsequent file growth. Directories however are not
	 * zero'ed as they should grow back initialized to empty.
	 */
	offset = lfs_blkoff(fs, length);
	lastseg = -1;
	bc = 0;

	if (ovp != fs->lfs_ivnode)
		lfs_seglock(fs, SEGM_PROT);
	if (offset == 0) {
		oip->i_size = oip->i_ffs1_size = length;
	} else if (!usepc) {
		lbn = lfs_lblkno(fs, length);
		aflags = B_CLRBUF;
		if (ioflag & IO_SYNC)
			aflags |= B_SYNC;
		error = lfs_balloc(ovp, length - 1, 1, cred, aflags, &bp);
		if (error) {
			lfs_reserve(fs, ovp, NULL,
			    -lfs_btofsb(fs, (2 * ULFS_NIADDR + 3) << lfs_sb_getbshift(fs)));
			goto errout;
		}
		obufsize = bp->b_bufsize;
		odb = lfs_btofsb(fs, bp->b_bcount);
		oip->i_size = oip->i_ffs1_size = length;
		size = lfs_blksize(fs, oip, lbn);
		if (ovp->v_type != VDIR)
			memset((char *)bp->b_data + offset, 0,
			       (u_int)(size - offset));
		allocbuf(bp, size, 1);
		if ((bp->b_flags & B_LOCKED) != 0 && bp->b_iodone == NULL) {
			mutex_enter(&lfs_lock);
			locked_queue_bytes -= obufsize - bp->b_bufsize;
			mutex_exit(&lfs_lock);
		}
		if (bp->b_oflags & BO_DELWRI) {
			lfs_sb_addavail(fs, odb - lfs_btofsb(fs, size));
			/* XXX shouldn't this wake up on lfs_availsleep? */
		}
		(void) VOP_BWRITE(bp->b_vp, bp);
	} else { /* vp->v_type == VREG && length < osize && offset != 0 */
		/*
		 * When truncating a regular file down to a non-block-aligned
		 * size, we must zero the part of last block which is past
		 * the new EOF.  We must synchronously flush the zeroed pages
		 * to disk since the new pages will be invalidated as soon
		 * as we inform the VM system of the new, smaller size.
		 * We must do this before acquiring the GLOCK, since fetching
		 * the pages will acquire the GLOCK internally.
		 * So there is a window where another thread could see a whole
		 * zeroed page past EOF, but that's life.
		 */
		daddr_t xlbn;
		voff_t eoz;

		aflags = ioflag & IO_SYNC ? B_SYNC : 0;
		error = ulfs_balloc_range(ovp, length - 1, 1, cred, aflags);
		if (error) {
			lfs_reserve(fs, ovp, NULL,
				    -lfs_btofsb(fs, (2 * ULFS_NIADDR + 3) << lfs_sb_getbshift(fs)));
			goto errout;
		}
		xlbn = lfs_lblkno(fs, length);
		size = lfs_blksize(fs, oip, xlbn);
		eoz = MIN(lfs_lblktosize(fs, xlbn) + size, osize);
		ubc_zerorange(&ovp->v_uobj, length, eoz - length,
		    UBC_UNMAP_FLAG(ovp));
		if (round_page(eoz) > round_page(length)) {
			mutex_enter(ovp->v_interlock);
			error = VOP_PUTPAGES(ovp, round_page(length),
			    round_page(eoz),
			    PGO_CLEANIT | PGO_DEACTIVATE |
			    ((ioflag & IO_SYNC) ? PGO_SYNCIO : 0));
			if (error) {
				lfs_reserve(fs, ovp, NULL,
					    -lfs_btofsb(fs, (2 * ULFS_NIADDR + 3) << lfs_sb_getbshift(fs)));
				goto errout;
			}
		}
	}

	genfs_node_wrlock(ovp);

	oip->i_size = oip->i_ffs1_size = length;
	uvm_vnp_setsize(ovp, length);

	/*
	 * Calculate index into inode's block list of
	 * last direct and indirect blocks (if any)
	 * which we want to keep.  Lastblock is -1 when
	 * the file is truncated to 0.
	 */
	/* Avoid sign overflow - XXX assumes that off_t is a quad_t. */
	if (length > QUAD_MAX - lfs_sb_getbsize(fs))
		lastblock = lfs_lblkno(fs, QUAD_MAX - lfs_sb_getbsize(fs));
	else
		lastblock = lfs_lblkno(fs, length + lfs_sb_getbsize(fs) - 1) - 1;
	lastiblock[SINGLE] = lastblock - ULFS_NDADDR;
	lastiblock[DOUBLE] = lastiblock[SINGLE] - LFS_NINDIR(fs);
	lastiblock[TRIPLE] = lastiblock[DOUBLE] - LFS_NINDIR(fs) * LFS_NINDIR(fs);
	nblocks = lfs_btofsb(fs, lfs_sb_getbsize(fs));
	/*
	 * Record changed file and block pointers before we start
	 * freeing blocks.  lastiblock values are also normalized to -1
	 * for calls to lfs_indirtrunc below.
	 */
	memcpy((void *)newblks, (void *)&oip->i_ffs1_db[0], sizeof newblks);
	for (level = TRIPLE; level >= SINGLE; level--)
		if (lastiblock[level] < 0) {
			newblks[ULFS_NDADDR+level] = 0;
			lastiblock[level] = -1;
		}
	for (i = ULFS_NDADDR - 1; i > lastblock; i--)
		newblks[i] = 0;

	oip->i_size = oip->i_ffs1_size = osize;
	error = lfs_vtruncbuf(ovp, lastblock + 1, false, 0);
	if (error && !allerror)
		allerror = error;

	/*
	 * Indirect blocks first.
	 */
	indir_lbn[SINGLE] = -ULFS_NDADDR;
	indir_lbn[DOUBLE] = indir_lbn[SINGLE] - LFS_NINDIR(fs) - 1;
	indir_lbn[TRIPLE] = indir_lbn[DOUBLE] - LFS_NINDIR(fs) * LFS_NINDIR(fs) - 1;
	for (level = TRIPLE; level >= SINGLE; level--) {
		bn = oip->i_ffs1_ib[level];
		if (bn != 0) {
			error = lfs_indirtrunc(oip, indir_lbn[level],
					       bn, lastiblock[level],
					       level, &count, &rcount,
					       &lastseg, &bc);
			if (error)
				allerror = error;
			real_released += rcount;
			blocksreleased += count;
			if (lastiblock[level] < 0) {
				if (oip->i_ffs1_ib[level] > 0)
					real_released += nblocks;
				blocksreleased += nblocks;
				oip->i_ffs1_ib[level] = 0;
				lfs_blkfree(fs, oip, bn, lfs_sb_getbsize(fs),
					    &lastseg, &bc);
        			lfs_deregister_block(ovp, bn);
			}
		}
		if (lastiblock[level] >= 0)
			goto done;
	}

	/*
	 * All whole direct blocks or frags.
	 */
	for (i = ULFS_NDADDR - 1; i > lastblock; i--) {
		long bsize, obsize;

		bn = oip->i_ffs1_db[i];
		if (bn == 0)
			continue;
		bsize = lfs_blksize(fs, oip, i);
		if (oip->i_ffs1_db[i] > 0) {
			/* Check for fragment size changes */
			obsize = oip->i_lfs_fragsize[i];
			real_released += lfs_btofsb(fs, obsize);
			oip->i_lfs_fragsize[i] = 0;
		} else
			obsize = 0;
		blocksreleased += lfs_btofsb(fs, bsize);
		oip->i_ffs1_db[i] = 0;
		lfs_blkfree(fs, oip, bn, obsize, &lastseg, &bc);
        	lfs_deregister_block(ovp, bn);
	}
	if (lastblock < 0)
		goto done;

	/*
	 * Finally, look for a change in size of the
	 * last direct block; release any frags.
	 */
	bn = oip->i_ffs1_db[lastblock];
	if (bn != 0) {
		long oldspace, newspace;
#if 0
		long olddspace;
#endif

		/*
		 * Calculate amount of space we're giving
		 * back as old block size minus new block size.
		 */
		oldspace = lfs_blksize(fs, oip, lastblock);
#if 0
		olddspace = oip->i_lfs_fragsize[lastblock];
#endif

		oip->i_size = oip->i_ffs1_size = length;
		newspace = lfs_blksize(fs, oip, lastblock);
		if (newspace == 0)
			panic("itrunc: newspace");
		if (oldspace - newspace > 0) {
			blocksreleased += lfs_btofsb(fs, oldspace - newspace);
		}
#if 0
		if (bn > 0 && olddspace - newspace > 0) {
			/* No segment accounting here, just vnode */
			real_released += lfs_btofsb(fs, olddspace - newspace);
		}
#endif
	}

done:
	/* Finish segment accounting corrections */
	lfs_update_seguse(fs, oip, lastseg, bc);
#ifdef DIAGNOSTIC
	for (level = SINGLE; level <= TRIPLE; level++)
		if ((newblks[ULFS_NDADDR + level] == 0) !=
		    ((oip->i_ffs1_ib[level]) == 0)) {
			panic("lfs itrunc1");
		}
	for (i = 0; i < ULFS_NDADDR; i++)
		if ((newblks[i] == 0) != (oip->i_ffs1_db[i] == 0)) {
			panic("lfs itrunc2");
		}
	if (length == 0 &&
	    (!LIST_EMPTY(&ovp->v_cleanblkhd) || !LIST_EMPTY(&ovp->v_dirtyblkhd)))
		panic("lfs itrunc3");
#endif /* DIAGNOSTIC */
	/*
	 * Put back the real size.
	 */
	oip->i_size = oip->i_ffs1_size = length;
	oip->i_lfs_effnblks -= blocksreleased;
	oip->i_ffs1_blocks -= real_released;
	mutex_enter(&lfs_lock);
	lfs_sb_addbfree(fs, blocksreleased);
	mutex_exit(&lfs_lock);
#ifdef DIAGNOSTIC
	if (oip->i_size == 0 &&
	    (oip->i_ffs1_blocks != 0 || oip->i_lfs_effnblks != 0)) {
		printf("lfs_truncate: truncate to 0 but %d blks/%jd effblks\n",
		       oip->i_ffs1_blocks, (intmax_t)oip->i_lfs_effnblks);
		panic("lfs_truncate: persistent blocks");
	}
#endif

	/*
	 * If we truncated to zero, take us off the paging queue.
	 */
	mutex_enter(&lfs_lock);
	if (oip->i_size == 0 && oip->i_flags & IN_PAGING) {
		oip->i_flags &= ~IN_PAGING;
		TAILQ_REMOVE(&fs->lfs_pchainhd, oip, i_lfs_pchain);
	}
	mutex_exit(&lfs_lock);

	oip->i_flag |= IN_CHANGE;
#if defined(LFS_QUOTA) || defined(LFS_QUOTA2)
	(void) lfs_chkdq(oip, -blocksreleased, NOCRED, 0);
#endif
	lfs_reserve(fs, ovp, NULL,
	    -lfs_btofsb(fs, (2 * ULFS_NIADDR + 3) << lfs_sb_getbshift(fs)));
	genfs_node_unlock(ovp);
  errout:
	oip->i_lfs_hiblk = lfs_lblkno(fs, oip->i_size + lfs_sb_getbsize(fs) - 1) - 1;
	if (ovp != fs->lfs_ivnode)
		lfs_segunlock(fs);
	return (allerror ? allerror : error);
}