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lfs_balloc.c revision 1.42
      1  1.42      yamt /*	$NetBSD: lfs_balloc.c,v 1.42 2003/05/18 12:59:05 yamt Exp $	*/
      2   1.2       cgd 
      3  1.11  perseant /*-
      4  1.36  perseant  * Copyright (c) 1999, 2000, 2001, 2002, 2003 The NetBSD Foundation, Inc.
      5  1.11  perseant  * All rights reserved.
      6  1.11  perseant  *
      7  1.11  perseant  * This code is derived from software contributed to The NetBSD Foundation
      8  1.11  perseant  * by Konrad E. Schroder <perseant (at) hhhh.org>.
      9  1.11  perseant  *
     10  1.11  perseant  * Redistribution and use in source and binary forms, with or without
     11  1.11  perseant  * modification, are permitted provided that the following conditions
     12  1.11  perseant  * are met:
     13  1.11  perseant  * 1. Redistributions of source code must retain the above copyright
     14  1.11  perseant  *    notice, this list of conditions and the following disclaimer.
     15  1.11  perseant  * 2. Redistributions in binary form must reproduce the above copyright
     16  1.11  perseant  *    notice, this list of conditions and the following disclaimer in the
     17  1.11  perseant  *    documentation and/or other materials provided with the distribution.
     18  1.11  perseant  * 3. All advertising materials mentioning features or use of this software
     19  1.11  perseant  *    must display the following acknowledgement:
     20  1.37  perseant  *	This product includes software developed by the NetBSD
     21  1.37  perseant  *	Foundation, Inc. and its contributors.
     22  1.11  perseant  * 4. Neither the name of The NetBSD Foundation nor the names of its
     23  1.11  perseant  *    contributors may be used to endorse or promote products derived
     24  1.11  perseant  *    from this software without specific prior written permission.
     25  1.11  perseant  *
     26  1.11  perseant  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     27  1.11  perseant  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     28  1.11  perseant  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     29  1.11  perseant  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     30  1.11  perseant  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     31  1.11  perseant  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     32  1.11  perseant  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     33  1.11  perseant  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     34  1.11  perseant  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     35  1.11  perseant  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     36  1.11  perseant  * POSSIBILITY OF SUCH DAMAGE.
     37  1.11  perseant  */
     38   1.1   mycroft /*
     39   1.1   mycroft  * Copyright (c) 1989, 1991, 1993
     40   1.1   mycroft  *	The Regents of the University of California.  All rights reserved.
     41   1.1   mycroft  *
     42   1.1   mycroft  * Redistribution and use in source and binary forms, with or without
     43   1.1   mycroft  * modification, are permitted provided that the following conditions
     44   1.1   mycroft  * are met:
     45   1.1   mycroft  * 1. Redistributions of source code must retain the above copyright
     46   1.1   mycroft  *    notice, this list of conditions and the following disclaimer.
     47   1.1   mycroft  * 2. Redistributions in binary form must reproduce the above copyright
     48   1.1   mycroft  *    notice, this list of conditions and the following disclaimer in the
     49   1.1   mycroft  *    documentation and/or other materials provided with the distribution.
     50   1.1   mycroft  * 3. All advertising materials mentioning features or use of this software
     51   1.1   mycroft  *    must display the following acknowledgement:
     52   1.1   mycroft  *	This product includes software developed by the University of
     53   1.1   mycroft  *	California, Berkeley and its contributors.
     54   1.1   mycroft  * 4. Neither the name of the University nor the names of its contributors
     55   1.1   mycroft  *    may be used to endorse or promote products derived from this software
     56   1.1   mycroft  *    without specific prior written permission.
     57   1.1   mycroft  *
     58   1.1   mycroft  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     59   1.1   mycroft  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     60   1.1   mycroft  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     61   1.1   mycroft  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     62   1.1   mycroft  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     63   1.1   mycroft  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     64   1.1   mycroft  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     65   1.1   mycroft  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     66   1.1   mycroft  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     67   1.1   mycroft  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     68   1.1   mycroft  * SUCH DAMAGE.
     69   1.1   mycroft  *
     70   1.5      fvdl  *	@(#)lfs_balloc.c	8.4 (Berkeley) 5/8/95
     71   1.1   mycroft  */
     72  1.30     lukem 
     73  1.30     lukem #include <sys/cdefs.h>
     74  1.42      yamt __KERNEL_RCSID(0, "$NetBSD: lfs_balloc.c,v 1.42 2003/05/18 12:59:05 yamt Exp $");
     75   1.8    scottr 
     76  1.28       mrg #if defined(_KERNEL_OPT)
     77   1.8    scottr #include "opt_quota.h"
     78   1.9    scottr #endif
     79   1.8    scottr 
     80   1.1   mycroft #include <sys/param.h>
     81   1.3  christos #include <sys/systm.h>
     82   1.1   mycroft #include <sys/buf.h>
     83   1.1   mycroft #include <sys/proc.h>
     84   1.1   mycroft #include <sys/vnode.h>
     85   1.1   mycroft #include <sys/mount.h>
     86   1.1   mycroft #include <sys/resourcevar.h>
     87   1.1   mycroft #include <sys/trace.h>
     88   1.1   mycroft 
     89   1.1   mycroft #include <miscfs/specfs/specdev.h>
     90   1.1   mycroft 
     91   1.1   mycroft #include <ufs/ufs/quota.h>
     92   1.1   mycroft #include <ufs/ufs/inode.h>
     93   1.1   mycroft #include <ufs/ufs/ufsmount.h>
     94   1.3  christos #include <ufs/ufs/ufs_extern.h>
     95   1.1   mycroft 
     96   1.1   mycroft #include <ufs/lfs/lfs.h>
     97   1.1   mycroft #include <ufs/lfs/lfs_extern.h>
     98   1.5      fvdl 
     99  1.36  perseant #include <uvm/uvm.h>
    100  1.36  perseant 
    101  1.35      fvdl int lfs_fragextend(struct vnode *, int, int, daddr_t, struct buf **, struct ucred *);
    102   1.5      fvdl 
    103  1.16  perseant /*
    104  1.16  perseant  * Allocate a block, and to inode and filesystem block accounting for it
    105  1.16  perseant  * and for any indirect blocks the may need to be created in order for
    106  1.16  perseant  * this block to be created.
    107  1.16  perseant  *
    108  1.16  perseant  * Blocks which have never been accounted for (i.e., which "do not exist")
    109  1.16  perseant  * have disk address 0, which is translated by ufs_bmap to the special value
    110  1.16  perseant  * UNASSIGNED == -1, as in the historical UFS.
    111  1.16  perseant  *
    112  1.16  perseant  * Blocks which have been accounted for but which have not yet been written
    113  1.16  perseant  * to disk are given the new special disk address UNWRITTEN == -2, so that
    114  1.16  perseant  * they can be differentiated from completely new blocks.
    115  1.16  perseant  */
    116  1.25  perseant /* VOP_BWRITE NIADDR+2 times */
    117   1.1   mycroft int
    118  1.29  perseant lfs_balloc(void *v)
    119  1.14      fvdl {
    120  1.14      fvdl 	struct vop_balloc_args /* {
    121  1.14      fvdl 		struct vnode *a_vp;
    122  1.14      fvdl 		off_t a_startoffset;
    123  1.14      fvdl 		int a_size;
    124  1.14      fvdl 		struct ucred *a_cred;
    125  1.14      fvdl 		int a_flags;
    126  1.14      fvdl 		struct buf *a_bpp;
    127  1.14      fvdl 	} */ *ap = v;
    128   1.1   mycroft 	struct vnode *vp;
    129   1.5      fvdl 	int offset;
    130   1.1   mycroft 	u_long iosize;
    131  1.19  perseant 	daddr_t daddr, idaddr;
    132  1.36  perseant 	struct buf *ibp, *bp, **bpp;
    133   1.1   mycroft 	struct inode *ip;
    134   1.1   mycroft 	struct lfs *fs;
    135  1.16  perseant 	struct indir indirs[NIADDR+2], *idp;
    136  1.35      fvdl 	daddr_t	lbn, lastblock;
    137  1.19  perseant 	int bb, bcount;
    138  1.11  perseant 	int error, frags, i, nsize, osize, num;
    139  1.14      fvdl 
    140  1.14      fvdl 	vp = ap->a_vp;
    141   1.1   mycroft 	ip = VTOI(vp);
    142   1.1   mycroft 	fs = ip->i_lfs;
    143  1.14      fvdl 	offset = blkoff(fs, ap->a_startoffset);
    144  1.14      fvdl 	iosize = ap->a_size;
    145  1.41      yamt 	KASSERT(iosize <= fs->lfs_bsize);
    146  1.14      fvdl 	lbn = lblkno(fs, ap->a_startoffset);
    147  1.36  perseant 	/* (void)lfs_check(vp, lbn, 0); */
    148  1.36  perseant 	bpp = ap->a_bpp;
    149  1.36  perseant 
    150   1.1   mycroft 	/*
    151   1.1   mycroft 	 * Three cases: it's a block beyond the end of file, it's a block in
    152   1.1   mycroft 	 * the file that may or may not have been assigned a disk address or
    153  1.19  perseant 	 * we're writing an entire block.
    154  1.19  perseant 	 *
    155  1.19  perseant 	 * Note, if the daddr is UNWRITTEN, the block already exists in
    156  1.37  perseant 	 * the cache (it was read or written earlier).	If so, make sure
    157  1.19  perseant 	 * we don't count it as a new block or zero out its contents. If
    158  1.19  perseant 	 * it did not, make sure we allocate any necessary indirect
    159  1.19  perseant 	 * blocks.
    160  1.19  perseant 	 *
    161   1.5      fvdl 	 * If we are writing a block beyond the end of the file, we need to
    162  1.11  perseant 	 * check if the old last block was a fragment.	If it was, we need
    163   1.5      fvdl 	 * to rewrite it.
    164   1.1   mycroft 	 */
    165  1.11  perseant 
    166  1.36  perseant 	if (bpp)
    167  1.36  perseant 		*bpp = NULL;
    168  1.11  perseant 
    169   1.5      fvdl 	/* Check for block beyond end of file and fragment extension needed. */
    170  1.40      fvdl 	lastblock = lblkno(fs, ip->i_size);
    171   1.5      fvdl 	if (lastblock < NDADDR && lastblock < lbn) {
    172   1.5      fvdl 		osize = blksize(fs, ip, lastblock);
    173   1.5      fvdl 		if (osize < fs->lfs_bsize && osize > 0) {
    174   1.5      fvdl 			if ((error = lfs_fragextend(vp, osize, fs->lfs_bsize,
    175  1.36  perseant 						    lastblock,
    176  1.36  perseant 						    (bpp ? &bp : NULL),
    177  1.29  perseant 						    ap->a_cred)))
    178  1.31       chs 				return (error);
    179  1.40      fvdl 			ip->i_ffs1_size = ip->i_size =
    180  1.40      fvdl 			    (lastblock + 1) * fs->lfs_bsize;
    181  1.40      fvdl 			uvm_vnp_setsize(vp, ip->i_size);
    182   1.5      fvdl 			ip->i_flag |= IN_CHANGE | IN_UPDATE;
    183  1.36  perseant 			if (bpp)
    184  1.36  perseant 				(void) VOP_BWRITE(bp);
    185   1.5      fvdl 		}
    186   1.5      fvdl 	}
    187   1.5      fvdl 
    188   1.5      fvdl 	/*
    189   1.5      fvdl 	 * If the block we are writing is a direct block, it's the last
    190   1.5      fvdl 	 * block in the file, and offset + iosize is less than a full
    191   1.5      fvdl 	 * block, we can write one or more fragments.  There are two cases:
    192   1.5      fvdl 	 * the block is brand new and we should allocate it the correct
    193   1.5      fvdl 	 * size or it already exists and contains some fragments and
    194   1.5      fvdl 	 * may need to extend it.
    195   1.5      fvdl 	 */
    196  1.40      fvdl 	if (lbn < NDADDR && lblkno(fs, ip->i_size) <= lbn) {
    197  1.11  perseant 		osize = blksize(fs, ip, lbn);
    198   1.5      fvdl 		nsize = fragroundup(fs, offset + iosize);
    199  1.40      fvdl 		if (lblktosize(fs, lbn) >= ip->i_size) {
    200   1.5      fvdl 			/* Brand new block or fragment */
    201  1.19  perseant 			frags = numfrags(fs, nsize);
    202  1.29  perseant 			bb = fragstofsb(fs, frags);
    203  1.36  perseant 			if (bpp) {
    204  1.36  perseant 				*ap->a_bpp = bp = getblk(vp, lbn, nsize, 0, 0);
    205  1.36  perseant 				bp->b_blkno = UNWRITTEN;
    206  1.38  perseant 				if (ap->a_flags & B_CLRBUF)
    207  1.38  perseant 					clrbuf(bp);
    208  1.36  perseant 			}
    209  1.21  perseant 			ip->i_lfs_effnblks += bb;
    210  1.19  perseant 			ip->i_lfs->lfs_bfree -= bb;
    211  1.40      fvdl 			ip->i_ffs1_db[lbn] = UNWRITTEN;
    212  1.19  perseant 		} else {
    213  1.11  perseant 			if (nsize <= osize) {
    214  1.11  perseant 				/* No need to extend */
    215  1.36  perseant 				if (bpp && (error = bread(vp, lbn, osize, NOCRED, &bp)))
    216  1.11  perseant 					return error;
    217  1.11  perseant 			} else {
    218  1.11  perseant 				/* Extend existing block */
    219  1.11  perseant 				if ((error =
    220  1.36  perseant 				     lfs_fragextend(vp, osize, nsize, lbn,
    221  1.36  perseant 						    (bpp ? &bp : NULL),
    222  1.29  perseant 						    ap->a_cred)))
    223  1.19  perseant 					return error;
    224  1.11  perseant 			}
    225  1.36  perseant 			if (bpp)
    226  1.36  perseant 				*bpp = bp;
    227   1.5      fvdl 		}
    228  1.19  perseant 		return 0;
    229  1.19  perseant 	}
    230  1.19  perseant 
    231  1.42      yamt 	error = ufs_bmaparray(vp, lbn, &daddr, &indirs[0], &num, NULL, NULL);
    232  1.19  perseant 	if (error)
    233  1.19  perseant 		return (error);
    234  1.19  perseant 	/*
    235  1.19  perseant 	 * Do byte accounting all at once, so we can gracefully fail *before*
    236  1.19  perseant 	 * we start assigning blocks.
    237  1.19  perseant 	 */
    238  1.19  perseant 	bb = VFSTOUFS(vp->v_mount)->um_seqinc;
    239  1.19  perseant 	bcount = 0;
    240  1.19  perseant 	if (daddr == UNASSIGNED) {
    241  1.19  perseant 		bcount = bb;
    242  1.19  perseant 	}
    243  1.19  perseant 	for (i = 1; i < num; ++i) {
    244  1.19  perseant 		if (!indirs[i].in_exists) {
    245  1.19  perseant 			bcount += bb;
    246  1.19  perseant 		}
    247  1.19  perseant 	}
    248  1.19  perseant 	if (ISSPACE(fs, bcount, ap->a_cred)) {
    249  1.19  perseant 		ip->i_lfs->lfs_bfree -= bcount;
    250  1.21  perseant 		ip->i_lfs_effnblks += bcount;
    251   1.5      fvdl 	} else {
    252  1.19  perseant 		return ENOSPC;
    253  1.19  perseant 	}
    254  1.19  perseant 
    255  1.19  perseant 	if (daddr == UNASSIGNED) {
    256  1.40      fvdl 		if (num > 0 && ip->i_ffs1_ib[indirs[0].in_off] == 0) {
    257  1.40      fvdl 			ip->i_ffs1_ib[indirs[0].in_off] = UNWRITTEN;
    258  1.19  perseant 		}
    259  1.19  perseant 
    260   1.5      fvdl 		/*
    261  1.19  perseant 		 * Create new indirect blocks if necessary
    262   1.5      fvdl 		 */
    263  1.19  perseant 		if (num > 1)
    264  1.40      fvdl 			idaddr = ip->i_ffs1_ib[indirs[0].in_off];
    265  1.19  perseant 		for (i = 1; i < num; ++i) {
    266  1.19  perseant 			ibp = getblk(vp, indirs[i].in_lbn, fs->lfs_bsize, 0,0);
    267  1.19  perseant 			if (!indirs[i].in_exists) {
    268  1.19  perseant 				clrbuf(ibp);
    269  1.19  perseant 				ibp->b_blkno = UNWRITTEN;
    270  1.19  perseant 			} else if (!(ibp->b_flags & (B_DELWRI | B_DONE))) {
    271  1.29  perseant 				ibp->b_blkno = fsbtodb(fs, idaddr);
    272  1.19  perseant 				ibp->b_flags |= B_READ;
    273  1.19  perseant 				VOP_STRATEGY(ibp);
    274  1.19  perseant 				biowait(ibp);
    275  1.19  perseant 			}
    276  1.19  perseant 			/*
    277  1.19  perseant 			 * This block exists, but the next one may not.
    278  1.19  perseant 			 * If that is the case mark it UNWRITTEN to keep
    279  1.19  perseant 			 * the accounting straight.
    280  1.19  perseant 			 */
    281  1.35      fvdl 			/* XXX ondisk32 */
    282  1.35      fvdl 			if (((int32_t *)ibp->b_data)[indirs[i].in_off] == 0)
    283  1.35      fvdl 				((int32_t *)ibp->b_data)[indirs[i].in_off] =
    284  1.19  perseant 					UNWRITTEN;
    285  1.35      fvdl 			/* XXX ondisk32 */
    286  1.35      fvdl 			idaddr = ((int32_t *)ibp->b_data)[indirs[i].in_off];
    287  1.19  perseant 			if ((error = VOP_BWRITE(ibp))) {
    288  1.19  perseant 				return error;
    289  1.19  perseant 			}
    290  1.19  perseant 		}
    291  1.19  perseant 	}
    292  1.19  perseant 
    293  1.19  perseant 
    294  1.19  perseant 	/*
    295  1.36  perseant 	 * Get the existing block from the cache, if requested.
    296  1.19  perseant 	 */
    297  1.29  perseant 	frags = fsbtofrags(fs, bb);
    298  1.36  perseant 	if (bpp)
    299  1.36  perseant 		*bpp = bp = getblk(vp, lbn, blksize(fs, ip, lbn), 0, 0);
    300  1.11  perseant 
    301   1.5      fvdl 	/*
    302   1.5      fvdl 	 * The block we are writing may be a brand new block
    303  1.19  perseant 	 * in which case we need to do accounting.
    304  1.15  perseant 	 *
    305  1.19  perseant 	 * We can tell a truly new block because ufs_bmaparray will say
    306  1.19  perseant 	 * it is UNASSIGNED.  Once we allocate it we will assign it the
    307  1.19  perseant 	 * disk address UNWRITTEN.
    308   1.5      fvdl 	 */
    309  1.16  perseant 	if (daddr == UNASSIGNED) {
    310  1.36  perseant 		if (bpp) {
    311  1.36  perseant 			if (ap->a_flags & B_CLRBUF)
    312  1.36  perseant 				clrbuf(bp);
    313  1.19  perseant 
    314  1.36  perseant 			/* Note the new address */
    315  1.36  perseant 			bp->b_blkno = UNWRITTEN;
    316  1.36  perseant 		}
    317  1.19  perseant 
    318  1.19  perseant 		switch (num) {
    319  1.19  perseant 		    case 0:
    320  1.40      fvdl 			ip->i_ffs1_db[lbn] = UNWRITTEN;
    321  1.19  perseant 			break;
    322  1.19  perseant 		    case 1:
    323  1.40      fvdl 			ip->i_ffs1_ib[indirs[0].in_off] = UNWRITTEN;
    324  1.19  perseant 			break;
    325  1.19  perseant 		    default:
    326  1.19  perseant 			idp = &indirs[num - 1];
    327  1.19  perseant 			if (bread(vp, idp->in_lbn, fs->lfs_bsize, NOCRED,
    328  1.19  perseant 				  &ibp))
    329  1.35      fvdl 				panic("lfs_balloc: bread bno %lld",
    330  1.35      fvdl 				    (long long)idp->in_lbn);
    331  1.35      fvdl 			/* XXX ondisk32 */
    332  1.35      fvdl 			((int32_t *)ibp->b_data)[idp->in_off] = UNWRITTEN;
    333  1.19  perseant 			VOP_BWRITE(ibp);
    334  1.15  perseant 		}
    335  1.36  perseant 	} else if (bpp && !(bp->b_flags & (B_DONE|B_DELWRI))) {
    336  1.15  perseant 		/*
    337  1.15  perseant 		 * Not a brand new block, also not in the cache;
    338  1.15  perseant 		 * read it in from disk.
    339  1.15  perseant 		 */
    340  1.15  perseant 		if (iosize == fs->lfs_bsize)
    341   1.5      fvdl 			/* Optimization: I/O is unnecessary. */
    342   1.5      fvdl 			bp->b_blkno = daddr;
    343  1.15  perseant 		else {
    344   1.5      fvdl 			/*
    345   1.5      fvdl 			 * We need to read the block to preserve the
    346   1.5      fvdl 			 * existing bytes.
    347   1.5      fvdl 			 */
    348   1.1   mycroft 			bp->b_blkno = daddr;
    349   1.1   mycroft 			bp->b_flags |= B_READ;
    350   1.1   mycroft 			VOP_STRATEGY(bp);
    351  1.31       chs 			return (biowait(bp));
    352   1.1   mycroft 		}
    353   1.1   mycroft 	}
    354  1.11  perseant 
    355   1.5      fvdl 	return (0);
    356   1.5      fvdl }
    357   1.5      fvdl 
    358  1.25  perseant /* VOP_BWRITE 1 time */
    359   1.5      fvdl int
    360  1.35      fvdl lfs_fragextend(struct vnode *vp, int osize, int nsize, daddr_t lbn, struct buf **bpp, struct ucred *cred)
    361   1.5      fvdl {
    362   1.5      fvdl 	struct inode *ip;
    363   1.5      fvdl 	struct lfs *fs;
    364   1.5      fvdl 	long bb;
    365   1.5      fvdl 	int error;
    366  1.11  perseant 	extern long locked_queue_bytes;
    367  1.26  perseant 	size_t obufsize;
    368   1.5      fvdl 
    369   1.5      fvdl 	ip = VTOI(vp);
    370   1.5      fvdl 	fs = ip->i_lfs;
    371  1.29  perseant 	bb = (long)fragstofsb(fs, numfrags(fs, nsize - osize));
    372  1.18  perseant 	error = 0;
    373  1.18  perseant 
    374  1.18  perseant 	/*
    375  1.36  perseant 	 * Get the seglock so we don't enlarge blocks while a segment
    376  1.36  perseant 	 * is being written.  If we're called with bpp==NULL, though,
    377  1.36  perseant 	 * we are only pretending to change a buffer, so we don't have to
    378  1.36  perseant 	 * lock.
    379  1.18  perseant 	 */
    380  1.26  perseant     top:
    381  1.36  perseant 	if (bpp) {
    382  1.36  perseant 		lockmgr(&fs->lfs_fraglock, LK_SHARED, 0);
    383  1.36  perseant 	}
    384  1.36  perseant 
    385  1.29  perseant 	if (!ISSPACE(fs, bb, cred)) {
    386  1.18  perseant 		error = ENOSPC;
    387  1.18  perseant 		goto out;
    388   1.5      fvdl 	}
    389  1.36  perseant 
    390  1.36  perseant 	/*
    391  1.36  perseant 	 * If we are not asked to actually return the block, all we need
    392  1.36  perseant 	 * to do is allocate space for it.  UBC will handle dirtying the
    393  1.36  perseant 	 * appropriate things and making sure it all goes to disk.
    394  1.36  perseant 	 * Don't bother to read in that case.
    395  1.36  perseant 	 */
    396  1.36  perseant 	if (bpp && (error = bread(vp, lbn, osize, NOCRED, bpp))) {
    397   1.5      fvdl 		brelse(*bpp);
    398  1.18  perseant 		goto out;
    399   1.5      fvdl 	}
    400  1.19  perseant #ifdef QUOTA
    401  1.29  perseant 	if ((error = chkdq(ip, bb, cred, 0))) {
    402  1.36  perseant 		if (bpp)
    403  1.36  perseant 			brelse(*bpp);
    404  1.19  perseant 		goto out;
    405  1.19  perseant 	}
    406  1.19  perseant #endif
    407  1.13  perseant 	/*
    408  1.26  perseant 	 * Adjust accounting for lfs_avail.  If there's not enough room,
    409  1.26  perseant 	 * we will have to wait for the cleaner, which we can't do while
    410  1.26  perseant 	 * holding a block busy or while holding the seglock.  In that case,
    411  1.26  perseant 	 * release both and start over after waiting.
    412  1.26  perseant 	 */
    413  1.33  perseant 
    414  1.36  perseant 	if (bpp && ((*bpp)->b_flags & B_DELWRI)) {
    415  1.26  perseant 		if (!lfs_fits(fs, bb)) {
    416  1.36  perseant 			if (bpp)
    417  1.36  perseant 				brelse(*bpp);
    418  1.26  perseant #ifdef QUOTA
    419  1.29  perseant 			chkdq(ip, -bb, cred, 0);
    420  1.26  perseant #endif
    421  1.33  perseant 			lockmgr(&fs->lfs_fraglock, LK_RELEASE, 0);
    422  1.26  perseant 			lfs_availwait(fs, bb);
    423  1.26  perseant 			goto top;
    424  1.26  perseant 		}
    425  1.26  perseant 		fs->lfs_avail -= bb;
    426  1.26  perseant 	}
    427  1.26  perseant 
    428  1.19  perseant 	fs->lfs_bfree -= bb;
    429  1.22  perseant 	ip->i_lfs_effnblks += bb;
    430   1.5      fvdl 	ip->i_flag |= IN_CHANGE | IN_UPDATE;
    431  1.26  perseant 
    432  1.36  perseant 	if (bpp) {
    433  1.36  perseant 		LFS_DEBUG_COUNTLOCKED("frag1");
    434  1.32  perseant 
    435  1.36  perseant 		obufsize = (*bpp)->b_bufsize;
    436  1.36  perseant 		allocbuf(*bpp, nsize);
    437  1.26  perseant 
    438  1.36  perseant 		/* Adjust locked-list accounting */
    439  1.36  perseant 		if (((*bpp)->b_flags & (B_LOCKED | B_CALL)) == B_LOCKED)
    440  1.36  perseant 			locked_queue_bytes += (*bpp)->b_bufsize - obufsize;
    441  1.32  perseant 
    442  1.36  perseant 		LFS_DEBUG_COUNTLOCKED("frag2");
    443  1.26  perseant 
    444  1.36  perseant 		bzero((char *)((*bpp)->b_data) + osize, (u_int)(nsize - osize));
    445  1.36  perseant 	}
    446  1.18  perseant 
    447  1.18  perseant     out:
    448  1.36  perseant 	if (bpp) {
    449  1.36  perseant 		lockmgr(&fs->lfs_fraglock, LK_RELEASE, 0);
    450  1.36  perseant 	}
    451  1.18  perseant 	return (error);
    452   1.1   mycroft }
    453