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Annotation of kernel/bsd/ufs/lfs/lfs_subr.c, revision 1.1

1.1     ! root        1: /*
        !             2:  * Copyright (c) 1999 Apple Computer, Inc. All rights reserved.
        !             3:  *
        !             4:  * @APPLE_LICENSE_HEADER_START@
        !             5:  * 
        !             6:  * Portions Copyright (c) 1999 Apple Computer, Inc.  All Rights
        !             7:  * Reserved.  This file contains Original Code and/or Modifications of
        !             8:  * Original Code as defined in and that are subject to the Apple Public
        !             9:  * Source License Version 1.1 (the "License").  You may not use this file
        !            10:  * except in compliance with the License.  Please obtain a copy of the
        !            11:  * License at http://www.apple.com/publicsource and read it before using
        !            12:  * this file.
        !            13:  * 
        !            14:  * The Original Code and all software distributed under the License are
        !            15:  * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
        !            16:  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
        !            17:  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
        !            18:  * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
        !            19:  * License for the specific language governing rights and limitations
        !            20:  * under the License.
        !            21:  * 
        !            22:  * @APPLE_LICENSE_HEADER_END@
        !            23:  */
        !            24: 
        !            25: /*     $NetBSD: lfs_subr.c,v 1.2 1994/06/29 06:47:00 cgd Exp $ */
        !            26: 
        !            27: /*
        !            28:  * Copyright (c) 1991, 1993
        !            29:  *     The Regents of the University of California.  All rights reserved.
        !            30:  *
        !            31:  * Redistribution and use in source and binary forms, with or without
        !            32:  * modification, are permitted provided that the following conditions
        !            33:  * are met:
        !            34:  * 1. Redistributions of source code must retain the above copyright
        !            35:  *    notice, this list of conditions and the following disclaimer.
        !            36:  * 2. Redistributions in binary form must reproduce the above copyright
        !            37:  *    notice, this list of conditions and the following disclaimer in the
        !            38:  *    documentation and/or other materials provided with the distribution.
        !            39:  * 3. All advertising materials mentioning features or use of this software
        !            40:  *    must display the following acknowledgement:
        !            41:  *     This product includes software developed by the University of
        !            42:  *     California, Berkeley and its contributors.
        !            43:  * 4. Neither the name of the University nor the names of its contributors
        !            44:  *    may be used to endorse or promote products derived from this software
        !            45:  *    without specific prior written permission.
        !            46:  *
        !            47:  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
        !            48:  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
        !            49:  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
        !            50:  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
        !            51:  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
        !            52:  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
        !            53:  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
        !            54:  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
        !            55:  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
        !            56:  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
        !            57:  * SUCH DAMAGE.
        !            58:  *
        !            59:  *     @(#)lfs_subr.c  8.2 (Berkeley) 9/21/93
        !            60:  */
        !            61: 
        !            62: #include <sys/param.h>
        !            63: #include <sys/namei.h>
        !            64: #include <sys/vnode.h>
        !            65: #include <sys/buf.h>
        !            66: #include <sys/mount.h>
        !            67: #include <sys/malloc.h>
        !            68: #include <sys/proc.h>
        !            69: 
        !            70: #include <ufs/ufs/quota.h>
        !            71: #include <ufs/ufs/inode.h>
        !            72: #include <ufs/lfs/lfs.h>
        !            73: #include <ufs/lfs/lfs_extern.h>
        !            74: 
        !            75: /*
        !            76:  * Return buffer with the contents of block "offset" from the beginning of
        !            77:  * directory "ip".  If "res" is non-zero, fill it in with a pointer to the
        !            78:  * remaining space in the directory.
        !            79:  */
        !            80: int
        !            81: lfs_blkatoff(ap)
        !            82:        struct vop_blkatoff_args /* {
        !            83:                struct vnode *a_vp;
        !            84:                off_t a_offset;
        !            85:                char **a_res;
        !            86:                struct buf **a_bpp;
        !            87:        } */ *ap;
        !            88: {
        !            89:        register struct lfs *fs;
        !            90:        struct inode *ip;
        !            91:        struct buf *bp;
        !            92:        daddr_t lbn;
        !            93:        int bsize, error;
        !            94: 
        !            95:        ip = VTOI(ap->a_vp);
        !            96:        fs = ip->i_lfs;
        !            97:        lbn = lblkno(fs, ap->a_offset);
        !            98:        bsize = blksize(fs);
        !            99: 
        !           100:        *ap->a_bpp = NULL;
        !           101:        if (error = bread(ap->a_vp, lbn, bsize, NOCRED, &bp)) {
        !           102:                brelse(bp);
        !           103:                return (error);
        !           104:        }
        !           105:        if (ap->a_res)
        !           106:                *ap->a_res = (char *)bp->b_data + blkoff(fs, ap->a_offset);
        !           107:        *ap->a_bpp = bp;
        !           108:        return (0);
        !           109: }
        !           110: 
        !           111: 
        !           112: /*
        !           113:  * lfs_seglock --
        !           114:  *     Single thread the segment writer.
        !           115:  */
        !           116: void
        !           117: lfs_seglock(fs, flags)
        !           118:        struct lfs *fs;
        !           119:        unsigned long flags;
        !           120: {
        !           121:        struct segment *sp;
        !           122:        int s;
        !           123: 
        !           124:        if (fs->lfs_seglock)
        !           125:                if (fs->lfs_lockpid == curproc->p_pid) {
        !           126:                        ++fs->lfs_seglock;
        !           127:                        fs->lfs_sp->seg_flags |= flags;
        !           128:                        return;                 
        !           129:                } else while (fs->lfs_seglock)
        !           130:                        (void)tsleep(&fs->lfs_seglock, PRIBIO + 1,
        !           131:                            "lfs seglock", 0);
        !           132: 
        !           133:        fs->lfs_seglock = 1;
        !           134:        fs->lfs_lockpid = curproc->p_pid;
        !           135: 
        !           136: //     sp = fs->lfs_sp = malloc(sizeof(struct segment), M_SEGMENT, M_WAITOK);
        !           137:        MALLOC(fs->lfs_sp, struct segment *, sizeof(struct segment), M_SEGMENT, M_WAITOK);
        !           138:        sp = fs->lfs_sp;
        !           139: //     sp->bpp = malloc(((LFS_SUMMARY_SIZE - sizeof(SEGSUM)) /
        !           140: //         sizeof(daddr_t) + 1) * sizeof(struct buf *), M_SEGMENT, M_WAITOK);
        !           141:        MALLOC(sp->bpp, caddr_t, ((LFS_SUMMARY_SIZE - sizeof(SEGSUM)) /
        !           142:            sizeof(daddr_t) + 1) * sizeof(struct buf *), M_SEGMENT, M_WAITOK);
        !           143:        sp->seg_flags = flags;
        !           144:        sp->vp = NULL;
        !           145:        (void) lfs_initseg(fs);
        !           146: 
        !           147:        /*
        !           148:         * Keep a cumulative count of the outstanding I/O operations.  If the
        !           149:         * disk drive catches up with us it could go to zero before we finish,
        !           150:         * so we artificially increment it by one until we've scheduled all of
        !           151:         * the writes we intend to do.
        !           152:         */
        !           153:        s = splbio();
        !           154:        ++fs->lfs_iocount;
        !           155:        splx(s);
        !           156: }
        !           157: /*
        !           158:  * lfs_segunlock --
        !           159:  *     Single thread the segment writer.
        !           160:  */
        !           161: void
        !           162: lfs_segunlock(fs)
        !           163:        struct lfs *fs;
        !           164: {
        !           165:        struct segment *sp;
        !           166:        unsigned long sync, ckp;
        !           167:        int s;
        !           168: 
        !           169:        if (fs->lfs_seglock == 1) {
        !           170: 
        !           171:                sp = fs->lfs_sp;
        !           172:                sync = sp->seg_flags & SEGM_SYNC;
        !           173:                ckp = sp->seg_flags & SEGM_CKP;
        !           174:                if (sp->bpp != sp->cbpp) {
        !           175:                        /* Free allocated segment summary */
        !           176:                        fs->lfs_offset -= LFS_SUMMARY_SIZE / DEV_BSIZE;
        !           177:                        brelvp(*sp->bpp);
        !           178:                        free((*sp->bpp)->b_data, M_SEGMENT);
        !           179:                        free(*sp->bpp, M_SEGMENT);
        !           180:                } else
        !           181:                        printf ("unlock to 0 with no summary");
        !           182:                free(sp->bpp, M_SEGMENT);
        !           183:                free(sp, M_SEGMENT);
        !           184: 
        !           185:                /*
        !           186:                 * If the I/O count is non-zero, sleep until it reaches zero.
        !           187:                 * At the moment, the user's process hangs around so we can
        !           188:                 * sleep.
        !           189:                 */
        !           190:                s = splbio();
        !           191:                --fs->lfs_iocount;
        !           192:                /*
        !           193:                 * We let checkpoints happen asynchronously.  That means
        !           194:                 * that during recovery, we have to roll forward between
        !           195:                 * the two segments described by the first and second
        !           196:                 * superblocks to make sure that the checkpoint described
        !           197:                 * by a superblock completed.
        !           198:                 */
        !           199:                if (sync && fs->lfs_iocount)
        !           200:                    (void)tsleep(&fs->lfs_iocount, PRIBIO + 1, "lfs vflush", 0);
        !           201:                splx(s);
        !           202:                if (ckp) {
        !           203:                        fs->lfs_nactive = 0;
        !           204:                        lfs_writesuper(fs);
        !           205:                }
        !           206:                --fs->lfs_seglock;
        !           207:                fs->lfs_lockpid = 0;
        !           208:                wakeup(&fs->lfs_seglock);
        !           209:        } else if (fs->lfs_seglock == 0) {
        !           210:                panic ("Seglock not held");
        !           211:        } else {
        !           212:                --fs->lfs_seglock;
        !           213:        }
        !           214: }

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