598 lines
18 KiB
C
598 lines
18 KiB
C
/* $NetBSD: ffs_alloc.c,v 1.27 2013/06/23 22:03:34 dholland Exp $ */
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/* From: NetBSD: ffs_alloc.c,v 1.50 2001/09/06 02:16:01 lukem Exp */
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/*
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* Copyright (c) 2002 Networks Associates Technology, Inc.
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* All rights reserved.
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*
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* This software was developed for the FreeBSD Project by Marshall
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* Kirk McKusick and Network Associates Laboratories, the Security
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* Research Division of Network Associates, Inc. under DARPA/SPAWAR
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* contract N66001-01-C-8035 ("CBOSS"), as part of the DARPA CHATS
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* research program
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*
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* Copyright (c) 1982, 1986, 1989, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* @(#)ffs_alloc.c 8.19 (Berkeley) 7/13/95
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*/
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#if HAVE_NBTOOL_CONFIG_H
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#include "nbtool_config.h"
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#endif
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#include <sys/cdefs.h>
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#if defined(__RCSID) && !defined(__lint)
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__RCSID("$NetBSD: ffs_alloc.c,v 1.27 2013/06/23 22:03:34 dholland Exp $");
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#endif /* !__lint */
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#include <sys/param.h>
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#include <sys/time.h>
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#include <errno.h>
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#include "makefs.h"
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#include <ufs/ufs/dinode.h>
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#include <ufs/ufs/ufs_bswap.h>
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#include <ufs/ffs/fs.h>
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#include "ffs/buf.h"
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#include "ffs/ufs_inode.h"
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#include "ffs/ffs_extern.h"
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static int scanc(u_int, const u_char *, const u_char *, int);
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static daddr_t ffs_alloccg(struct inode *, int, daddr_t, int);
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static daddr_t ffs_alloccgblk(struct inode *, struct buf *, daddr_t);
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static daddr_t ffs_hashalloc(struct inode *, int, daddr_t, int,
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daddr_t (*)(struct inode *, int, daddr_t, int));
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static int32_t ffs_mapsearch(struct fs *, struct cg *, daddr_t, int);
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/* in ffs_tables.c */
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extern const int inside[], around[];
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extern const u_char * const fragtbl[];
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/*
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* Allocate a block in the file system.
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*
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* The size of the requested block is given, which must be some
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* multiple of fs_fsize and <= fs_bsize.
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* A preference may be optionally specified. If a preference is given
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* the following hierarchy is used to allocate a block:
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* 1) allocate the requested block.
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* 2) allocate a rotationally optimal block in the same cylinder.
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* 3) allocate a block in the same cylinder group.
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* 4) quadradically rehash into other cylinder groups, until an
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* available block is located.
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* If no block preference is given the following hierarchy is used
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* to allocate a block:
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* 1) allocate a block in the cylinder group that contains the
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* inode for the file.
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* 2) quadradically rehash into other cylinder groups, until an
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* available block is located.
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*/
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int
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ffs_alloc(struct inode *ip, daddr_t lbn __unused, daddr_t bpref, int size,
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daddr_t *bnp)
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{
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struct fs *fs = ip->i_fs;
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daddr_t bno;
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int cg;
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*bnp = 0;
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if (size > fs->fs_bsize || ffs_fragoff(fs, size) != 0) {
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errx(1, "ffs_alloc: bad size: bsize %d size %d",
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fs->fs_bsize, size);
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}
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if (size == fs->fs_bsize && fs->fs_cstotal.cs_nbfree == 0)
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goto nospace;
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if (bpref >= fs->fs_size)
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bpref = 0;
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if (bpref == 0)
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cg = ino_to_cg(fs, ip->i_number);
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else
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cg = dtog(fs, bpref);
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bno = ffs_hashalloc(ip, cg, bpref, size, ffs_alloccg);
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if (bno > 0) {
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DIP_ADD(ip, blocks, size / DEV_BSIZE);
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*bnp = bno;
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return (0);
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}
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nospace:
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return (ENOSPC);
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}
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/*
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* Select the desired position for the next block in a file. The file is
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* logically divided into sections. The first section is composed of the
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* direct blocks. Each additional section contains fs_maxbpg blocks.
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*
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* If no blocks have been allocated in the first section, the policy is to
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* request a block in the same cylinder group as the inode that describes
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* the file. If no blocks have been allocated in any other section, the
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* policy is to place the section in a cylinder group with a greater than
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* average number of free blocks. An appropriate cylinder group is found
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* by using a rotor that sweeps the cylinder groups. When a new group of
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* blocks is needed, the sweep begins in the cylinder group following the
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* cylinder group from which the previous allocation was made. The sweep
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* continues until a cylinder group with greater than the average number
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* of free blocks is found. If the allocation is for the first block in an
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* indirect block, the information on the previous allocation is unavailable;
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* here a best guess is made based upon the logical block number being
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* allocated.
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*
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* If a section is already partially allocated, the policy is to
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* contiguously allocate fs_maxcontig blocks. The end of one of these
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* contiguous blocks and the beginning of the next is physically separated
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* so that the disk head will be in transit between them for at least
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* fs_rotdelay milliseconds. This is to allow time for the processor to
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* schedule another I/O transfer.
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*/
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/* XXX ondisk32 */
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daddr_t
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ffs_blkpref_ufs1(struct inode *ip, daddr_t lbn, int indx, int32_t *bap)
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{
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struct fs *fs;
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int cg;
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int avgbfree, startcg;
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fs = ip->i_fs;
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if (indx % fs->fs_maxbpg == 0 || bap[indx - 1] == 0) {
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if (lbn < UFS_NDADDR + FFS_NINDIR(fs)) {
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cg = ino_to_cg(fs, ip->i_number);
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return (fs->fs_fpg * cg + fs->fs_frag);
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}
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/*
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* Find a cylinder with greater than average number of
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* unused data blocks.
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*/
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if (indx == 0 || bap[indx - 1] == 0)
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startcg =
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ino_to_cg(fs, ip->i_number) + lbn / fs->fs_maxbpg;
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else
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startcg = dtog(fs,
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ufs_rw32(bap[indx - 1], UFS_FSNEEDSWAP(fs)) + 1);
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startcg %= fs->fs_ncg;
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avgbfree = fs->fs_cstotal.cs_nbfree / fs->fs_ncg;
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for (cg = startcg; cg < fs->fs_ncg; cg++)
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if (fs->fs_cs(fs, cg).cs_nbfree >= avgbfree)
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return (fs->fs_fpg * cg + fs->fs_frag);
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for (cg = 0; cg <= startcg; cg++)
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if (fs->fs_cs(fs, cg).cs_nbfree >= avgbfree)
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return (fs->fs_fpg * cg + fs->fs_frag);
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return (0);
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}
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/*
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* We just always try to lay things out contiguously.
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*/
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return ufs_rw32(bap[indx - 1], UFS_FSNEEDSWAP(fs)) + fs->fs_frag;
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}
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daddr_t
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ffs_blkpref_ufs2(struct inode *ip, daddr_t lbn, int indx, int64_t *bap)
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{
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struct fs *fs;
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int cg;
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int avgbfree, startcg;
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fs = ip->i_fs;
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if (indx % fs->fs_maxbpg == 0 || bap[indx - 1] == 0) {
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if (lbn < UFS_NDADDR + FFS_NINDIR(fs)) {
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cg = ino_to_cg(fs, ip->i_number);
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return (fs->fs_fpg * cg + fs->fs_frag);
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}
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/*
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* Find a cylinder with greater than average number of
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* unused data blocks.
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*/
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if (indx == 0 || bap[indx - 1] == 0)
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startcg =
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ino_to_cg(fs, ip->i_number) + lbn / fs->fs_maxbpg;
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else
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startcg = dtog(fs,
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ufs_rw64(bap[indx - 1], UFS_FSNEEDSWAP(fs)) + 1);
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startcg %= fs->fs_ncg;
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avgbfree = fs->fs_cstotal.cs_nbfree / fs->fs_ncg;
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for (cg = startcg; cg < fs->fs_ncg; cg++)
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if (fs->fs_cs(fs, cg).cs_nbfree >= avgbfree) {
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return (fs->fs_fpg * cg + fs->fs_frag);
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}
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for (cg = 0; cg < startcg; cg++)
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if (fs->fs_cs(fs, cg).cs_nbfree >= avgbfree) {
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return (fs->fs_fpg * cg + fs->fs_frag);
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}
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return (0);
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}
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/*
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* We just always try to lay things out contiguously.
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*/
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return ufs_rw64(bap[indx - 1], UFS_FSNEEDSWAP(fs)) + fs->fs_frag;
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}
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/*
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* Implement the cylinder overflow algorithm.
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*
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* The policy implemented by this algorithm is:
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* 1) allocate the block in its requested cylinder group.
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* 2) quadradically rehash on the cylinder group number.
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* 3) brute force search for a free block.
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*
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* `size': size for data blocks, mode for inodes
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*/
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/*VARARGS5*/
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static daddr_t
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ffs_hashalloc(struct inode *ip, int cg, daddr_t pref, int size,
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daddr_t (*allocator)(struct inode *, int, daddr_t, int))
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{
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struct fs *fs;
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daddr_t result;
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int i, icg = cg;
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fs = ip->i_fs;
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/*
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* 1: preferred cylinder group
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*/
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result = (*allocator)(ip, cg, pref, size);
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if (result)
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return (result);
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/*
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* 2: quadratic rehash
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*/
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for (i = 1; i < fs->fs_ncg; i *= 2) {
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cg += i;
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if (cg >= fs->fs_ncg)
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cg -= fs->fs_ncg;
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result = (*allocator)(ip, cg, 0, size);
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if (result)
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return (result);
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}
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/*
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* 3: brute force search
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* Note that we start at i == 2, since 0 was checked initially,
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* and 1 is always checked in the quadratic rehash.
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*/
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cg = (icg + 2) % fs->fs_ncg;
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for (i = 2; i < fs->fs_ncg; i++) {
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result = (*allocator)(ip, cg, 0, size);
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if (result)
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return (result);
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cg++;
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if (cg == fs->fs_ncg)
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cg = 0;
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}
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return (0);
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}
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/*
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* Determine whether a block can be allocated.
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*
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* Check to see if a block of the appropriate size is available,
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* and if it is, allocate it.
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*/
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static daddr_t
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ffs_alloccg(struct inode *ip, int cg, daddr_t bpref, int size)
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{
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struct cg *cgp;
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struct buf *bp;
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daddr_t bno, blkno;
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int error, frags, allocsiz, i;
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struct fs *fs = ip->i_fs;
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const int needswap = UFS_FSNEEDSWAP(fs);
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if (fs->fs_cs(fs, cg).cs_nbfree == 0 && size == fs->fs_bsize)
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return (0);
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error = bread(ip->i_devvp, FFS_FSBTODB(fs, cgtod(fs, cg)),
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(int)fs->fs_cgsize, NULL, 0, &bp);
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if (error) {
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return (0);
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}
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cgp = (struct cg *)bp->b_data;
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if (!cg_chkmagic(cgp, needswap) ||
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(cgp->cg_cs.cs_nbfree == 0 && size == fs->fs_bsize)) {
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brelse(bp, 0);
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return (0);
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}
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if (size == fs->fs_bsize) {
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bno = ffs_alloccgblk(ip, bp, bpref);
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bwrite(bp);
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return (bno);
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}
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/*
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* check to see if any fragments are already available
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* allocsiz is the size which will be allocated, hacking
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* it down to a smaller size if necessary
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*/
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frags = ffs_numfrags(fs, size);
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for (allocsiz = frags; allocsiz < fs->fs_frag; allocsiz++)
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if (cgp->cg_frsum[allocsiz] != 0)
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break;
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if (allocsiz == fs->fs_frag) {
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/*
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* no fragments were available, so a block will be
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* allocated, and hacked up
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*/
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if (cgp->cg_cs.cs_nbfree == 0) {
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brelse(bp, 0);
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return (0);
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}
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bno = ffs_alloccgblk(ip, bp, bpref);
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bpref = dtogd(fs, bno);
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for (i = frags; i < fs->fs_frag; i++)
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setbit(cg_blksfree(cgp, needswap), bpref + i);
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i = fs->fs_frag - frags;
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ufs_add32(cgp->cg_cs.cs_nffree, i, needswap);
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fs->fs_cstotal.cs_nffree += i;
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fs->fs_cs(fs, cg).cs_nffree += i;
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fs->fs_fmod = 1;
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ufs_add32(cgp->cg_frsum[i], 1, needswap);
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bdwrite(bp);
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return (bno);
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}
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bno = ffs_mapsearch(fs, cgp, bpref, allocsiz);
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for (i = 0; i < frags; i++)
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clrbit(cg_blksfree(cgp, needswap), bno + i);
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ufs_add32(cgp->cg_cs.cs_nffree, -frags, needswap);
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fs->fs_cstotal.cs_nffree -= frags;
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fs->fs_cs(fs, cg).cs_nffree -= frags;
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fs->fs_fmod = 1;
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ufs_add32(cgp->cg_frsum[allocsiz], -1, needswap);
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if (frags != allocsiz)
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ufs_add32(cgp->cg_frsum[allocsiz - frags], 1, needswap);
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blkno = cg * fs->fs_fpg + bno;
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bdwrite(bp);
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return blkno;
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}
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/*
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* Allocate a block in a cylinder group.
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*
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* This algorithm implements the following policy:
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* 1) allocate the requested block.
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* 2) allocate a rotationally optimal block in the same cylinder.
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* 3) allocate the next available block on the block rotor for the
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* specified cylinder group.
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* Note that this routine only allocates fs_bsize blocks; these
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* blocks may be fragmented by the routine that allocates them.
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*/
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static daddr_t
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ffs_alloccgblk(struct inode *ip, struct buf *bp, daddr_t bpref)
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{
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struct cg *cgp;
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daddr_t blkno;
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int32_t bno;
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struct fs *fs = ip->i_fs;
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const int needswap = UFS_FSNEEDSWAP(fs);
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u_int8_t *blksfree;
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cgp = (struct cg *)bp->b_data;
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blksfree = cg_blksfree(cgp, needswap);
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if (bpref == 0 || dtog(fs, bpref) != ufs_rw32(cgp->cg_cgx, needswap)) {
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bpref = ufs_rw32(cgp->cg_rotor, needswap);
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} else {
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bpref = ffs_blknum(fs, bpref);
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bno = dtogd(fs, bpref);
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/*
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* if the requested block is available, use it
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*/
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if (ffs_isblock(fs, blksfree, ffs_fragstoblks(fs, bno)))
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goto gotit;
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}
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/*
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* Take the next available one in this cylinder group.
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*/
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bno = ffs_mapsearch(fs, cgp, bpref, (int)fs->fs_frag);
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if (bno < 0)
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return (0);
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cgp->cg_rotor = ufs_rw32(bno, needswap);
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gotit:
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blkno = ffs_fragstoblks(fs, bno);
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ffs_clrblock(fs, blksfree, (long)blkno);
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ffs_clusteracct(fs, cgp, blkno, -1);
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ufs_add32(cgp->cg_cs.cs_nbfree, -1, needswap);
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fs->fs_cstotal.cs_nbfree--;
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fs->fs_cs(fs, ufs_rw32(cgp->cg_cgx, needswap)).cs_nbfree--;
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fs->fs_fmod = 1;
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blkno = ufs_rw32(cgp->cg_cgx, needswap) * fs->fs_fpg + bno;
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return (blkno);
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}
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/*
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* Free a block or fragment.
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*
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* The specified block or fragment is placed back in the
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* free map. If a fragment is deallocated, a possible
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* block reassembly is checked.
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*/
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void
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ffs_blkfree(struct inode *ip, daddr_t bno, long size)
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{
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struct cg *cgp;
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struct buf *bp;
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int32_t fragno, cgbno;
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int i, error, cg, blk, frags, bbase;
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struct fs *fs = ip->i_fs;
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const int needswap = UFS_FSNEEDSWAP(fs);
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if (size > fs->fs_bsize || ffs_fragoff(fs, size) != 0 ||
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ffs_fragnum(fs, bno) + ffs_numfrags(fs, size) > fs->fs_frag) {
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errx(1, "blkfree: bad size: bno %lld bsize %d size %ld",
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(long long)bno, fs->fs_bsize, size);
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}
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cg = dtog(fs, bno);
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if (bno >= fs->fs_size) {
|
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warnx("bad block %lld, ino %llu", (long long)bno,
|
|
(unsigned long long)ip->i_number);
|
|
return;
|
|
}
|
|
error = bread(ip->i_devvp, FFS_FSBTODB(fs, cgtod(fs, cg)),
|
|
(int)fs->fs_cgsize, NULL, 0, &bp);
|
|
if (error) {
|
|
brelse(bp, 0);
|
|
return;
|
|
}
|
|
cgp = (struct cg *)bp->b_data;
|
|
if (!cg_chkmagic(cgp, needswap)) {
|
|
brelse(bp, 0);
|
|
return;
|
|
}
|
|
cgbno = dtogd(fs, bno);
|
|
if (size == fs->fs_bsize) {
|
|
fragno = ffs_fragstoblks(fs, cgbno);
|
|
if (!ffs_isfreeblock(fs, cg_blksfree(cgp, needswap), fragno)) {
|
|
errx(1, "blkfree: freeing free block %lld",
|
|
(long long)bno);
|
|
}
|
|
ffs_setblock(fs, cg_blksfree(cgp, needswap), fragno);
|
|
ffs_clusteracct(fs, cgp, fragno, 1);
|
|
ufs_add32(cgp->cg_cs.cs_nbfree, 1, needswap);
|
|
fs->fs_cstotal.cs_nbfree++;
|
|
fs->fs_cs(fs, cg).cs_nbfree++;
|
|
} else {
|
|
bbase = cgbno - ffs_fragnum(fs, cgbno);
|
|
/*
|
|
* decrement the counts associated with the old frags
|
|
*/
|
|
blk = blkmap(fs, cg_blksfree(cgp, needswap), bbase);
|
|
ffs_fragacct(fs, blk, cgp->cg_frsum, -1, needswap);
|
|
/*
|
|
* deallocate the fragment
|
|
*/
|
|
frags = ffs_numfrags(fs, size);
|
|
for (i = 0; i < frags; i++) {
|
|
if (isset(cg_blksfree(cgp, needswap), cgbno + i)) {
|
|
errx(1, "blkfree: freeing free frag: block %lld",
|
|
(long long)(cgbno + i));
|
|
}
|
|
setbit(cg_blksfree(cgp, needswap), cgbno + i);
|
|
}
|
|
ufs_add32(cgp->cg_cs.cs_nffree, i, needswap);
|
|
fs->fs_cstotal.cs_nffree += i;
|
|
fs->fs_cs(fs, cg).cs_nffree += i;
|
|
/*
|
|
* add back in counts associated with the new frags
|
|
*/
|
|
blk = blkmap(fs, cg_blksfree(cgp, needswap), bbase);
|
|
ffs_fragacct(fs, blk, cgp->cg_frsum, 1, needswap);
|
|
/*
|
|
* if a complete block has been reassembled, account for it
|
|
*/
|
|
fragno = ffs_fragstoblks(fs, bbase);
|
|
if (ffs_isblock(fs, cg_blksfree(cgp, needswap), fragno)) {
|
|
ufs_add32(cgp->cg_cs.cs_nffree, -fs->fs_frag, needswap);
|
|
fs->fs_cstotal.cs_nffree -= fs->fs_frag;
|
|
fs->fs_cs(fs, cg).cs_nffree -= fs->fs_frag;
|
|
ffs_clusteracct(fs, cgp, fragno, 1);
|
|
ufs_add32(cgp->cg_cs.cs_nbfree, 1, needswap);
|
|
fs->fs_cstotal.cs_nbfree++;
|
|
fs->fs_cs(fs, cg).cs_nbfree++;
|
|
}
|
|
}
|
|
fs->fs_fmod = 1;
|
|
bdwrite(bp);
|
|
}
|
|
|
|
|
|
static int
|
|
scanc(u_int size, const u_char *cp, const u_char table[], int mask)
|
|
{
|
|
const u_char *end = &cp[size];
|
|
|
|
while (cp < end && (table[*cp] & mask) == 0)
|
|
cp++;
|
|
return (end - cp);
|
|
}
|
|
|
|
/*
|
|
* Find a block of the specified size in the specified cylinder group.
|
|
*
|
|
* It is a panic if a request is made to find a block if none are
|
|
* available.
|
|
*/
|
|
static int32_t
|
|
ffs_mapsearch(struct fs *fs, struct cg *cgp, daddr_t bpref, int allocsiz)
|
|
{
|
|
int32_t bno;
|
|
int start, len, loc, i;
|
|
int blk, field, subfield, pos;
|
|
int ostart, olen;
|
|
const int needswap = UFS_FSNEEDSWAP(fs);
|
|
|
|
/*
|
|
* find the fragment by searching through the free block
|
|
* map for an appropriate bit pattern
|
|
*/
|
|
if (bpref)
|
|
start = dtogd(fs, bpref) / NBBY;
|
|
else
|
|
start = ufs_rw32(cgp->cg_frotor, needswap) / NBBY;
|
|
len = howmany(fs->fs_fpg, NBBY) - start;
|
|
ostart = start;
|
|
olen = len;
|
|
loc = scanc((u_int)len,
|
|
(const u_char *)&cg_blksfree(cgp, needswap)[start],
|
|
(const u_char *)fragtbl[fs->fs_frag],
|
|
(1 << (allocsiz - 1 + (fs->fs_frag % NBBY))));
|
|
if (loc == 0) {
|
|
len = start + 1;
|
|
start = 0;
|
|
loc = scanc((u_int)len,
|
|
(const u_char *)&cg_blksfree(cgp, needswap)[0],
|
|
(const u_char *)fragtbl[fs->fs_frag],
|
|
(1 << (allocsiz - 1 + (fs->fs_frag % NBBY))));
|
|
if (loc == 0) {
|
|
errx(1,
|
|
"ffs_alloccg: map corrupted: start %d len %d offset %d %ld",
|
|
ostart, olen,
|
|
ufs_rw32(cgp->cg_freeoff, needswap),
|
|
(long)cg_blksfree(cgp, needswap) - (long)cgp);
|
|
/* NOTREACHED */
|
|
}
|
|
}
|
|
bno = (start + len - loc) * NBBY;
|
|
cgp->cg_frotor = ufs_rw32(bno, needswap);
|
|
/*
|
|
* found the byte in the map
|
|
* sift through the bits to find the selected frag
|
|
*/
|
|
for (i = bno + NBBY; bno < i; bno += fs->fs_frag) {
|
|
blk = blkmap(fs, cg_blksfree(cgp, needswap), bno);
|
|
blk <<= 1;
|
|
field = around[allocsiz];
|
|
subfield = inside[allocsiz];
|
|
for (pos = 0; pos <= fs->fs_frag - allocsiz; pos++) {
|
|
if ((blk & field) == subfield)
|
|
return (bno + pos);
|
|
field <<= 1;
|
|
subfield <<= 1;
|
|
}
|
|
}
|
|
errx(1, "ffs_alloccg: block not in map: bno %lld", (long long)bno);
|
|
return (-1);
|
|
}
|