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/*      $NetBSD: ffs_alloc.c,v 1.18 2011/03/06 17:08:42 bouyer Exp $    */

/* From: NetBSD: ffs_alloc.c,v 1.50 2001/09/06 02:16:01 lukem Exp */

/*

 * Copyright (c) 2002 Networks Associates Technology, Inc.

 * All rights reserved.

 *

 * This software was developed for the FreeBSD Project by Marshall

 * Kirk McKusick and Network Associates Laboratories, the Security

 * Research Division of Network Associates, Inc. under DARPA/SPAWAR

 * contract N66001-01-C-8035 ("CBOSS"), as part of the DARPA CHATS

 * research program

 *

 * Copyright (c) 1982, 1986, 1989, 1993

 *      The Regents of the University of California.  All rights reserved.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions

 * are met:

 * 1. Redistributions of source code must retain the above copyright

 *    notice, this list of conditions and the following disclaimer.

 * 2. Redistributions in binary form must reproduce the above copyright

 *    notice, this list of conditions and the following disclaimer in the

 *    documentation and/or other materials provided with the distribution.

 * 3. Neither the name of the University nor the names of its contributors

 *    may be used to endorse or promote products derived from this software

 *    without specific prior written permission.

 *

 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND

 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE

 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE

 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE

 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL

 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS

 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)

 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT

 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY

 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF

 * SUCH DAMAGE.

 *

 *      @(#)ffs_alloc.c 8.19 (Berkeley) 7/13/95

 */

#if HAVE_NBTOOL_CONFIG_H

#include "nbtool_config.h"

#endif

#include <sys/cdefs.h>

#if defined(__RCSID) && !defined(__lint)

__RCSID("$NetBSD: ffs_alloc.c,v 1.18 2011/03/06 17:08:42 bouyer Exp $");

#endif  /* !__lint */

#include <sys/param.h>

#include <sys/time.h>

#include <errno.h>

#include "common.h"

#include "makefs.h"

#include "dinode.h"

#include "ufs_bswap.h"

#include "fs.h"

#include "buf.h"

#include "ufs_inode.h"

#include "ffs_extern.h"

static int scanc(u_int, const u_char *, const u_char *, int);

static daddr_t ffs_alloccg(struct inode *, int, daddr_t, int);

static daddr_t ffs_alloccgblk(struct inode *, struct buf *, daddr_t);

static daddr_t ffs_hashalloc(struct inode *, int, daddr_t, int,

                     daddr_t (*)(struct inode *, int, daddr_t, int));

static int32_t ffs_mapsearch(struct fs *, struct cg *, daddr_t, int);

/* in ffs_tables.c */

extern const int inside[], around[];

extern const u_char * const fragtbl[];

/*

 * Allocate a block in the file system.

 *

 * The size of the requested block is given, which must be some

 * multiple of fs_fsize and <= fs_bsize.

 * A preference may be optionally specified. If a preference is given

 * the following hierarchy is used to allocate a block:

 *   1) allocate the requested block.

 *   2) allocate a rotationally optimal block in the same cylinder.

 *   3) allocate a block in the same cylinder group.

 *   4) quadradically rehash into other cylinder groups, until an

 *      available block is located.

 * If no block preference is given the following hierarchy is used

 * to allocate a block:

 *   1) allocate a block in the cylinder group that contains the

 *      inode for the file.

 *   2) quadradically rehash into other cylinder groups, until an

 *      available block is located.

 */

int

ffs_alloc(struct inode *ip, daddr_t lbn, daddr_t bpref, int size,

    daddr_t *bnp)

{

        struct fs *fs = ip->i_fs;

        daddr_t bno;

        int cg;

        *bnp = 0;

        if ((u_int)size > fs->fs_bsize || fragoff(fs, size) != 0) {

                errx(1, "ffs_alloc: bad size: bsize %d size %d",

                    fs->fs_bsize, size);

        }

        if (size == fs->fs_bsize && fs->fs_cstotal.cs_nbfree == 0)

                goto nospace;

        if (bpref >= fs->fs_size)

                bpref = 0;

        if (bpref == 0)

                cg = ino_to_cg(fs, ip->i_number);

        else

                cg = dtog(fs, bpref);

        bno = ffs_hashalloc(ip, cg, bpref, size, ffs_alloccg);

        if (bno > 0) {

                DIP_ADD(ip, blocks, size / DEV_BSIZE);

                *bnp = bno;

                return (0);

        }

nospace:

        return (ENOSPC);

}

/*

 * Select the desired position for the next block in a file.  The file is

 * logically divided into sections. The first section is composed of the

 * direct blocks. Each additional section contains fs_maxbpg blocks.

 *

 * If no blocks have been allocated in the first section, the policy is to

 * request a block in the same cylinder group as the inode that describes

 * the file. If no blocks have been allocated in any other section, the

 * policy is to place the section in a cylinder group with a greater than

 * average number of free blocks.  An appropriate cylinder group is found

 * by using a rotor that sweeps the cylinder groups. When a new group of

 * blocks is needed, the sweep begins in the cylinder group following the

 * cylinder group from which the previous allocation was made. The sweep

 * continues until a cylinder group with greater than the average number

 * of free blocks is found. If the allocation is for the first block in an

 * indirect block, the information on the previous allocation is unavailable;

 * here a best guess is made based upon the logical block number being

 * allocated.

 *

 * If a section is already partially allocated, the policy is to

 * contiguously allocate fs_maxcontig blocks.  The end of one of these

 * contiguous blocks and the beginning of the next is physically separated

 * so that the disk head will be in transit between them for at least

 * fs_rotdelay milliseconds.  This is to allow time for the processor to

 * schedule another I/O transfer.

 */

/* XXX ondisk32 */

daddr_t

ffs_blkpref_ufs1(struct inode *ip, daddr_t lbn, int indx, int32_t *bap)

{

        struct fs *fs;

        int cg;

        int avgbfree, startcg;

        fs = ip->i_fs;

        if (indx % fs->fs_maxbpg == 0 || bap[indx - 1] == 0) {

                if (lbn < NDADDR + NINDIR(fs)) {

                        cg = ino_to_cg(fs, ip->i_number);

                        return (fs->fs_fpg * cg + fs->fs_frag);

                }

                /*

                 * Find a cylinder with greater than average number of

                 * unused data blocks.

                 */

                if (indx == 0 || bap[indx - 1] == 0)

                        startcg =

                            ino_to_cg(fs, ip->i_number) + lbn / fs->fs_maxbpg;

                else

                        startcg = dtog(fs,

                                ufs_rw32(bap[indx - 1], UFS_FSNEEDSWAP(fs)) + 1);

                startcg %= fs->fs_ncg;

                avgbfree = fs->fs_cstotal.cs_nbfree / fs->fs_ncg;

                for (cg = startcg; cg < fs->fs_ncg; cg++)

                        if (fs->fs_cs(fs, cg).cs_nbfree >= avgbfree)

                                return (fs->fs_fpg * cg + fs->fs_frag);

                for (cg = 0; cg <= startcg; cg++)

                        if (fs->fs_cs(fs, cg).cs_nbfree >= avgbfree)

                                return (fs->fs_fpg * cg + fs->fs_frag);

                return (0);

        }

        /*

         * We just always try to lay things out contiguously.

         */

        return ufs_rw32(bap[indx - 1], UFS_FSNEEDSWAP(fs)) + fs->fs_frag;

}

daddr_t

ffs_blkpref_ufs2(ip, lbn, indx, bap)

        struct inode *ip;

        daddr_t lbn;

        int indx;

        int64_t *bap;

{

        struct fs *fs;

        int cg;

        int avgbfree, startcg;

        fs = ip->i_fs;

        if (indx % fs->fs_maxbpg == 0 || bap[indx - 1] == 0) {

                if (lbn < NDADDR + NINDIR(fs)) {

                        cg = ino_to_cg(fs, ip->i_number);

                        return (fs->fs_fpg * cg + fs->fs_frag);

                }

                /*

                 * Find a cylinder with greater than average number of

                 * unused data blocks.

                 */

                if (indx == 0 || bap[indx - 1] == 0)

                        startcg =

                            ino_to_cg(fs, ip->i_number) + lbn / fs->fs_maxbpg;

                else

                        startcg = dtog(fs,

                                ufs_rw64(bap[indx - 1], UFS_FSNEEDSWAP(fs)) + 1);

                startcg %= fs->fs_ncg;

                avgbfree = fs->fs_cstotal.cs_nbfree / fs->fs_ncg;

                for (cg = startcg; cg < fs->fs_ncg; cg++)

                        if (fs->fs_cs(fs, cg).cs_nbfree >= avgbfree) {

                                return (fs->fs_fpg * cg + fs->fs_frag);

                        }

                for (cg = 0; cg < startcg; cg++)

                        if (fs->fs_cs(fs, cg).cs_nbfree >= avgbfree) {

                                return (fs->fs_fpg * cg + fs->fs_frag);

                        }

                return (0);

        }

        /*

         * We just always try to lay things out contiguously.

         */

        return ufs_rw64(bap[indx - 1], UFS_FSNEEDSWAP(fs)) + fs->fs_frag;

}

/*

 * Implement the cylinder overflow algorithm.

 *

 * The policy implemented by this algorithm is:

 *   1) allocate the block in its requested cylinder group.

 *   2) quadradically rehash on the cylinder group number.

 *   3) brute force search for a free block.

 *

 * `size':      size for data blocks, mode for inodes

 */

/*VARARGS5*/

static daddr_t

ffs_hashalloc(struct inode *ip, int cg, daddr_t pref, int size,

    daddr_t (*allocator)(struct inode *, int, daddr_t, int))

{

        struct fs *fs;

        daddr_t result;

        int i, icg = cg;

        fs = ip->i_fs;

        /*

         * 1: preferred cylinder group

         */

        result = (*allocator)(ip, cg, pref, size);

        if (result)

                return (result);

        /*

         * 2: quadratic rehash

         */

        for (i = 1; i < fs->fs_ncg; i *= 2) {

                cg += i;

                if (cg >= fs->fs_ncg)

                        cg -= fs->fs_ncg;

                result = (*allocator)(ip, cg, 0, size);

                if (result)

                        return (result);

        }

        /*

         * 3: brute force search

         * Note that we start at i == 2, since 0 was checked initially,

         * and 1 is always checked in the quadratic rehash.

         */

        cg = (icg + 2) % fs->fs_ncg;

        for (i = 2; i < fs->fs_ncg; i++) {

                result = (*allocator)(ip, cg, 0, size);

                if (result)

                        return (result);

                cg++;

                if (cg == fs->fs_ncg)

                        cg = 0;

        }

        return (0);

}

/*

 * Determine whether a block can be allocated.

 *

 * Check to see if a block of the appropriate size is available,

 * and if it is, allocate it.

 */

static daddr_t

ffs_alloccg(struct inode *ip, int cg, daddr_t bpref, int size)

{

        struct cg *cgp;

        struct buf *bp;

        daddr_t bno, blkno;

        int error, frags, allocsiz, i;

        struct fs *fs = ip->i_fs;

        const int needswap = UFS_FSNEEDSWAP(fs);

        if (fs->fs_cs(fs, cg).cs_nbfree == 0 && size == fs->fs_bsize)

                return (0);

        error = bread(ip->i_fd, ip->i_fs, fsbtodb(fs, cgtod(fs, cg)),

                (int)fs->fs_cgsize, &bp);

        if (error) {

                brelse(bp);

                return (0);

        }

        cgp = (struct cg *)bp->b_data;

        if (!cg_chkmagic(cgp, needswap) ||

            (cgp->cg_cs.cs_nbfree == 0 && size == fs->fs_bsize)) {

                brelse(bp);

                return (0);

        }

        if (size == fs->fs_bsize) {

                bno = ffs_alloccgblk(ip, bp, bpref);

                bdwrite(bp);

                return (bno);

        }

        /*

         * check to see if any fragments are already available

         * allocsiz is the size which will be allocated, hacking

         * it down to a smaller size if necessary

         */

        frags = numfrags(fs, size);

        for (allocsiz = frags; allocsiz < fs->fs_frag; allocsiz++)

                if (cgp->cg_frsum[allocsiz] != 0)

                        break;

        if (allocsiz == fs->fs_frag) {

                /*

                 * no fragments were available, so a block will be

                 * allocated, and hacked up

                 */

                if (cgp->cg_cs.cs_nbfree == 0) {

                        brelse(bp);

                        return (0);

                }

                bno = ffs_alloccgblk(ip, bp, bpref);

                bpref = dtogd(fs, bno);

                for (i = frags; i < fs->fs_frag; i++)

                        setbit(cg_blksfree(cgp, needswap), bpref + i);

                i = fs->fs_frag - frags;

                ufs_add32(cgp->cg_cs.cs_nffree, i, needswap);

                fs->fs_cstotal.cs_nffree += i;

                fs->fs_cs(fs, cg).cs_nffree += i;

                fs->fs_fmod = 1;

                ufs_add32(cgp->cg_frsum[i], 1, needswap);

                bdwrite(bp);

                return (bno);

        }

        bno = ffs_mapsearch(fs, cgp, bpref, allocsiz);

        for (i = 0; i < frags; i++)

                clrbit(cg_blksfree(cgp, needswap), bno + i);

        ufs_add32(cgp->cg_cs.cs_nffree, -frags, needswap);

        fs->fs_cstotal.cs_nffree -= frags;

        fs->fs_cs(fs, cg).cs_nffree -= frags;

        fs->fs_fmod = 1;

        ufs_add32(cgp->cg_frsum[allocsiz], -1, needswap);

        if (frags != allocsiz)

                ufs_add32(cgp->cg_frsum[allocsiz - frags], 1, needswap);

        blkno = cg * fs->fs_fpg + bno;

        bdwrite(bp);

        return blkno;

}

/*

 * Allocate a block in a cylinder group.

 *

 * This algorithm implements the following policy:

 *   1) allocate the requested block.

 *   2) allocate a rotationally optimal block in the same cylinder.

 *   3) allocate the next available block on the block rotor for the

 *      specified cylinder group.

 * Note that this routine only allocates fs_bsize blocks; these

 * blocks may be fragmented by the routine that allocates them.

 */

static daddr_t

ffs_alloccgblk(struct inode *ip, struct buf *bp, daddr_t bpref)

{

        struct cg *cgp;

        daddr_t blkno;

        int32_t bno;

        struct fs *fs = ip->i_fs;

        const int needswap = UFS_FSNEEDSWAP(fs);

        u_int8_t *blksfree;

        cgp = (struct cg *)bp->b_data;

        blksfree = cg_blksfree(cgp, needswap);

        if (bpref == 0 || dtog(fs, bpref) != ufs_rw32(cgp->cg_cgx, needswap)) {

                bpref = ufs_rw32(cgp->cg_rotor, needswap);

        } else {

                bpref = blknum(fs, bpref);

                bno = dtogd(fs, bpref);

                /*

                 * if the requested block is available, use it

                 */

                if (ffs_isblock(fs, blksfree, fragstoblks(fs, bno)))

                        goto gotit;

        }

        /*

         * Take the next available one in this cylinder group.

         */

        bno = ffs_mapsearch(fs, cgp, bpref, (int)fs->fs_frag);

        if (bno < 0)

                return (0);

        cgp->cg_rotor = ufs_rw32(bno, needswap);

gotit:

        blkno = fragstoblks(fs, bno);

        ffs_clrblock(fs, blksfree, (long)blkno);

        ffs_clusteracct(fs, cgp, blkno, -1);

        ufs_add32(cgp->cg_cs.cs_nbfree, -1, needswap);

        fs->fs_cstotal.cs_nbfree--;

        fs->fs_cs(fs, ufs_rw32(cgp->cg_cgx, needswap)).cs_nbfree--;

        fs->fs_fmod = 1;

        blkno = ufs_rw32(cgp->cg_cgx, needswap) * fs->fs_fpg + bno;

        return (blkno);

}

/*

 * Free a block or fragment.

 *

 * The specified block or fragment is placed back in the

 * free map. If a fragment is deallocated, a possible

 * block reassembly is checked.

 */

void

ffs_blkfree(struct inode *ip, daddr_t bno, long size)

{

        struct cg *cgp;

        struct buf *bp;

        int32_t fragno, cgbno;

        int i, error, cg, blk, frags, bbase;

        struct fs *fs = ip->i_fs;

        const int needswap = UFS_FSNEEDSWAP(fs);

        if ((u_int)size > fs->fs_bsize || fragoff(fs, size) != 0 ||

            fragnum(fs, bno) + numfrags(fs, size) > fs->fs_frag) {

                errx(1, "blkfree: bad size: bno %lld bsize %d size %ld",

                    (long long)bno, fs->fs_bsize, size);

        }

        cg = dtog(fs, bno);

        if (bno >= fs->fs_size) {

                warnx("bad block %lld, ino %llu", (long long)bno,

                    (unsigned long long)ip->i_number);

                return;

        }

        error = bread(ip->i_fd, ip->i_fs, fsbtodb(fs, cgtod(fs, cg)),

                (int)fs->fs_cgsize, &bp);

        if (error) {

                brelse(bp);

                return;

        }

        cgp = (struct cg *)bp->b_data;

        if (!cg_chkmagic(cgp, needswap)) {

                brelse(bp);

                return;

        }

        cgbno = dtogd(fs, bno);

        if (size == fs->fs_bsize) {

                fragno = 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 - 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 = 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 = 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);

}