library.c

早期freebsd实现

/*-
 * Copyright (c) 1992, 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. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. 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.
 */

#ifndef lint
static char sccsid[] = "@(#)library.c	8.1 (Berkeley) 6/4/93";
#endif /* not lint */

#include <sys/param.h>
#include <sys/time.h>
#include <sys/stat.h>
#include <sys/mount.h>
#include <sys/types.h>
#include <sys/mman.h>

#include <ufs/ufs/dinode.h>
#include <ufs/lfs/lfs.h>

#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include "clean.h"

void	 add_blocks __P((FS_INFO *, BLOCK_INFO *, int *, SEGSUM *, caddr_t,
	     daddr_t, daddr_t));
void	 add_inodes __P((FS_INFO *, BLOCK_INFO *, int *, SEGSUM *, caddr_t,
	     daddr_t));
int	 bi_compare __P((const void *, const void *));
int	 bi_toss __P((const void *, const void *, const void *));
void	 get_ifile __P((FS_INFO *, int));
int	 get_superblock __P((FS_INFO *, struct lfs *));
int	 pseg_valid __P((FS_INFO *, SEGSUM *));

/*
 * This function will get information on a a filesystem which matches
 * the name and type given.  If a "name" is in a filesystem of the given
 * type, then buf is filled with that filesystem's info, and the
 * a non-zero value is returned.
 */
int
fs_getmntinfo(buf, name, type)
	struct	statfs	**buf;
	char	*name;
	int	type;
{
	/* allocate space for the filesystem info */
	*buf = (struct statfs *)malloc(sizeof(struct statfs));
	if (*buf == NULL)
		return 0;

	/* grab the filesystem info */
	if (statfs(name, *buf) < 0) {
		free(*buf);
		return 0;
	}

	/* check to see if it's the one we want */
	if (((*buf)->f_type != type) ||
	    strncmp(name, (*buf)->f_mntonname, MNAMELEN)) {
		/* "this is not the filesystem you're looking for */
		free(*buf);
		return 0;
	}

	return 1;
}

/*
 * Get all the information available on an LFS file system.
 * Returns an pointer to an FS_INFO structure, NULL on error.
 */
FS_INFO *
get_fs_info (lstatfsp, use_mmap)
	struct statfs *lstatfsp;	/* IN: pointer to statfs struct */
	int use_mmap;			/* IN: mmap or read */
{
	FS_INFO	*fsp;
	int	i;
	
	fsp = (FS_INFO *)malloc(sizeof(FS_INFO));
	if (fsp == NULL)
		return NULL;
	bzero(fsp, sizeof(FS_INFO));

	fsp->fi_statfsp = lstatfsp;
	if (get_superblock (fsp, &fsp->fi_lfs))
		err(1, "get_fs_info: get_superblock failed");
	fsp->fi_daddr_shift =
	     fsp->fi_lfs.lfs_bshift - fsp->fi_lfs.lfs_fsbtodb;
	get_ifile (fsp, use_mmap);
	return (fsp);
}

/*
 * If we are reading the ifile then we need to refresh it.  Even if
 * we are mmapping it, it might have grown.  Finally, we need to 
 * refresh the file system information (statfs) info.
 */
void
reread_fs_info(fsp, use_mmap)
	FS_INFO *fsp;	/* IN: prointer fs_infos to reread */
	int use_mmap;
{
	int i;
	
	if (statfs(fsp->fi_statfsp->f_mntonname, fsp->fi_statfsp))
		err(1, "reread_fs_info: statfs failed");
	get_ifile (fsp, use_mmap);
}

/* 
 * Gets the superblock from disk (possibly in face of errors) 
 */
int
get_superblock (fsp, sbp)
	FS_INFO *fsp;		/* local file system info structure */
	struct lfs *sbp;
{
	char mntfromname[MNAMELEN+1];
        int fid;

	strcpy(mntfromname, "/dev/r");
	strcat(mntfromname, fsp->fi_statfsp->f_mntfromname+5);

	if ((fid = open(mntfromname, O_RDONLY, (mode_t)0)) < 0) {
		err(0, "get_superblock: bad open");
		return (-1);
	}

	get(fid, LFS_LABELPAD, sbp, sizeof(struct lfs));
	close (fid);
	
	return (0);
}

/* 
 * This function will map the ifile into memory.  It causes a
 * fatal error on failure.
 */
void
get_ifile (fsp, use_mmap)
	FS_INFO	*fsp;
	int use_mmap;

{
	struct stat file_stat;
	caddr_t ifp;
	char *ifile_name;
	int count, fid;

	ifp = NULL;
	ifile_name = malloc(strlen(fsp->fi_statfsp->f_mntonname) +
	    strlen(IFILE_NAME)+2);
	strcat(strcat(strcpy(ifile_name, fsp->fi_statfsp->f_mntonname), "/"),
	    IFILE_NAME);

	if ((fid = open(ifile_name, O_RDWR, (mode_t)0)) < 0)
		err(1, "get_ifile: bad open");

	if (fstat (fid, &file_stat))
		err(1, "get_ifile: fstat failed");

	if (use_mmap && file_stat.st_size == fsp->fi_ifile_length) {
		(void) close(fid);
		return;
	}

	/* get the ifile */
	if (use_mmap) {
		if (fsp->fi_cip)
			munmap((caddr_t)fsp->fi_cip, fsp->fi_ifile_length);
		ifp = mmap ((caddr_t)0, file_stat.st_size,
		    PROT_READ|PROT_WRITE, 0, fid, (off_t)0);
		if (ifp ==  (caddr_t)(-1))
			err(1, "get_ifile: mmap failed");
	} else {
		if (fsp->fi_cip)
			free(fsp->fi_cip);
		if (!(ifp = malloc (file_stat.st_size)))
			err (1, "get_ifile: malloc failed"); 
redo_read:
		count = read (fid, ifp, (size_t) file_stat.st_size);

		if (count < 0)
			err(1, "get_ifile: bad ifile read"); 
		else if (count < file_stat.st_size) {
			err(0, "get_ifile");
			if (lseek(fid, 0, SEEK_SET) < 0)
				err(1, "get_ifile: bad ifile lseek"); 
			goto redo_read;
		}
	}
	fsp->fi_ifile_length = file_stat.st_size;
	close (fid);

	fsp->fi_cip = (CLEANERINFO *)ifp;
	fsp->fi_segusep = (SEGUSE *)(ifp + CLEANSIZE(fsp));
	fsp->fi_ifilep  = (IFILE *)((caddr_t)fsp->fi_segusep + SEGTABSIZE(fsp));

	/*
	 * The number of ifile entries is equal to the number of blocks
	 * blocks in the ifile minus the ones allocated to cleaner info
	 * and segment usage table multiplied by the number of ifile
	 * entries per page.
	 */
	fsp->fi_ifile_count = (fsp->fi_ifile_length >> fsp->fi_lfs.lfs_bshift -
	    fsp->fi_lfs.lfs_cleansz - fsp->fi_lfs.lfs_segtabsz) *
	    fsp->fi_lfs.lfs_ifpb;

	free (ifile_name);
}

/*
 * This function will scan a segment and return a list of
 * <inode, blocknum> pairs which indicate which blocks were
 * contained as live data within the segment when the segment
 * summary was read (it may have "died" since then).  Any given
 * pair will be listed at most once.
 */
int 
lfs_segmapv(fsp, seg, seg_buf, blocks, bcount)
	FS_INFO *fsp;		/* pointer to local file system information */
	int seg;		/* the segment number */
	caddr_t seg_buf;	/* the buffer containing the segment's data */
	BLOCK_INFO **blocks;	/* OUT: array of block_info for live blocks */
	int *bcount;		/* OUT: number of active blocks in segment */
{
	BLOCK_INFO *bip;
	SEGSUM *sp;
	SEGUSE *sup;
	FINFO *fip;
	struct lfs *lfsp;
	caddr_t s, segend;
	daddr_t pseg_addr, seg_addr;
	int i, nelem, nblocks, sumsize;
	time_t timestamp;

	lfsp = &fsp->fi_lfs;
	nelem = 2 * lfsp->lfs_ssize;
	if (!(bip = malloc(nelem * sizeof(BLOCK_INFO))))
		goto err0;

	sup = SEGUSE_ENTRY(lfsp, fsp->fi_segusep, seg);
	s = seg_buf + (sup->su_flags & SEGUSE_SUPERBLOCK ? LFS_SBPAD : 0);
	seg_addr = sntoda(lfsp, seg);
	pseg_addr = seg_addr + (sup->su_flags & SEGUSE_SUPERBLOCK ? btodb(LFS_SBPAD) : 0);
#ifdef VERBOSE
		printf("\tsegment buffer at: 0x%x\tseg_addr 0x%x\n", s, seg_addr);
#endif /* VERBOSE */

	*bcount = 0;
	for (segend = seg_buf + seg_size(lfsp), timestamp = 0; s < segend; ) {
		sp = (SEGSUM *)s;

#ifdef VERBOSE
		printf("\tpartial at: 0x%x\n", pseg_addr);
		print_SEGSUM(lfsp, sp);
		fflush(stdout);
#endif /* VERBOSE */

		nblocks = pseg_valid(fsp, sp);
		if (nblocks <= 0)
			break;

		/* Check if we have hit old data */
		if (timestamp > ((SEGSUM*)s)->ss_create)
			break;
		timestamp = ((SEGSUM*)s)->ss_create;

#ifdef DIAGNOSTIC
		/* Verfiy size of summary block */
		sumsize = sizeof(SEGSUM) +
		    (sp->ss_ninos + INOPB(lfsp) - 1) / INOPB(lfsp);
		for (fip = (FINFO *)(sp + 1); i < sp->ss_nfinfo; ++i) {
			sumsize += sizeof(FINFO) +
			    (fip->fi_nblocks - 1) * sizeof(daddr_t);
			fip = (FINFO *)(&fip->fi_blocks[fip->fi_nblocks]);
		}
		if (sumsize > LFS_SUMMARY_SIZE) {
			fprintf(stderr,
			    "Segment %d summary block too big: %d\n",
			    seg, sumsize);
			exit(1);
		}
#endif

		if (*bcount + nblocks + sp->ss_ninos > nelem) {
			nelem = *bcount + nblocks + sp->ss_ninos;
			bip = realloc (bip, nelem * sizeof(BLOCK_INFO));
			if (!bip)
				goto err0;
		}
		add_blocks(fsp, bip, bcount, sp, seg_buf, seg_addr, pseg_addr);
		add_inodes(fsp, bip, bcount, sp, seg_buf, seg_addr);
		pseg_addr += fsbtodb(lfsp, nblocks) +
		    bytetoda(fsp, LFS_SUMMARY_SIZE);
		s += (nblocks << lfsp->lfs_bshift) + LFS_SUMMARY_SIZE;
	}
	qsort(bip, *bcount, sizeof(BLOCK_INFO), bi_compare);
	toss(bip, bcount, sizeof(BLOCK_INFO), bi_toss, NULL);
#ifdef VERBOSE
	{
		BLOCK_INFO *_bip;
		int i;