xref: /csrg-svn/sbin/dump/traverse.c (revision 50905)
147082Smckusick /*-
247082Smckusick  * Copyright (c) 1980, 1988, 1991 The Regents of the University of California.
347082Smckusick  * All rights reserved.
447082Smckusick  *
547082Smckusick  * %sccs.include.redist.c%
622041Sdist  */
75329Smckusic 
822041Sdist #ifndef lint
9*50905Smckusick static char sccsid[] = "@(#)traverse.c	5.13 (Berkeley) 08/28/91";
1046584Storek #endif /* not lint */
1122041Sdist 
1250499Smckusick #ifdef sunos
1350499Smckusick #include <stdio.h>
1450499Smckusick #include <ctype.h>
1546795Sbostic #include <sys/param.h>
1650499Smckusick #include <sys/stat.h>
1750499Smckusick #include <sys/time.h>
1850499Smckusick #include <sys/dir.h>
1950499Smckusick #include <sys/vnode.h>
2050499Smckusick #include <ufs/inode.h>
2150499Smckusick #else
2250499Smckusick #include <sys/param.h>
2346795Sbostic #include <ufs/dir.h>
2446795Sbostic #include <ufs/dinode.h>
2550499Smckusick #endif
2646795Sbostic #include <ufs/fs.h>
2746795Sbostic #include <protocols/dumprestore.h>
2846795Sbostic #ifdef __STDC__
2946795Sbostic #include <unistd.h>
3046795Sbostic #include <string.h>
3146795Sbostic #endif
321426Sroot #include "dump.h"
331426Sroot 
3446792Smckusick void	dmpindir();
3546792Smckusick #define	HASDUMPEDFILE	0x1
3646792Smckusick #define	HASSUBDIRS	0x2
3746584Storek 
3846584Storek /*
3946584Storek  * This is an estimation of the number of TP_BSIZE blocks in the file.
4046584Storek  * It estimates the number of blocks in files with holes by assuming
4146584Storek  * that all of the blocks accounted for by di_blocks are data blocks
4246584Storek  * (when some of the blocks are usually used for indirect pointers);
4346584Storek  * hence the estimate may be high.
4446584Storek  */
4546792Smckusick long
4647058Smckusick blockest(dp)
4747058Smckusick 	register struct dinode *dp;
4846584Storek {
4946792Smckusick 	long blkest, sizeest;
5046584Storek 
5146584Storek 	/*
5247058Smckusick 	 * dp->di_size is the size of the file in bytes.
5347058Smckusick 	 * dp->di_blocks stores the number of sectors actually in the file.
5446584Storek 	 * If there are more sectors than the size would indicate, this just
5546584Storek 	 *	means that there are indirect blocks in the file or unused
5646584Storek 	 *	sectors in the last file block; we can safely ignore these
5746792Smckusick 	 *	(blkest = sizeest below).
5846584Storek 	 * If the file is bigger than the number of sectors would indicate,
5946584Storek 	 *	then the file has holes in it.	In this case we must use the
6046584Storek 	 *	block count to estimate the number of data blocks used, but
6146584Storek 	 *	we use the actual size for estimating the number of indirect
6246792Smckusick 	 *	dump blocks (sizeest vs. blkest in the indirect block
6346792Smckusick 	 *	calculation).
6446584Storek 	 */
6547058Smckusick 	blkest = howmany(dbtob(dp->di_blocks), TP_BSIZE);
6647058Smckusick 	sizeest = howmany(dp->di_size, TP_BSIZE);
6746792Smckusick 	if (blkest > sizeest)
6846792Smckusick 		blkest = sizeest;
6947058Smckusick 	if (dp->di_size > sblock->fs_bsize * NDADDR) {
7046584Storek 		/* calculate the number of indirect blocks on the dump tape */
7146792Smckusick 		blkest +=
7246792Smckusick 			howmany(sizeest - NDADDR * sblock->fs_bsize / TP_BSIZE,
7346584Storek 			TP_NINDIR);
7446584Storek 	}
7546792Smckusick 	return (blkest + 1);
7646584Storek }
7746584Storek 
7846792Smckusick /*
7946792Smckusick  * Dump pass 1.
8046792Smckusick  *
8146792Smckusick  * Walk the inode list for a filesystem to find all allocated inodes
8246792Smckusick  * that have been modified since the previous dump time. Also, find all
8346792Smckusick  * the directories in the filesystem.
8446792Smckusick  */
8546792Smckusick mapfiles(maxino, tapesize)
8646792Smckusick 	ino_t maxino;
8746792Smckusick 	long *tapesize;
8846584Storek {
8946792Smckusick 	register int mode;
9046792Smckusick 	register ino_t ino;
9146792Smckusick 	register struct dinode *dp;
9246792Smckusick 	int anydirskipped = 0;
9346584Storek 
9446792Smckusick 	for (ino = 0; ino < maxino; ino++) {
9546792Smckusick 		dp = getino(ino);
9646792Smckusick 		if ((mode = (dp->di_mode & IFMT)) == 0)
9746792Smckusick 			continue;
9846792Smckusick 		SETINO(ino, usedinomap);
9946792Smckusick 		if (mode == IFDIR)
10046792Smckusick 			SETINO(ino, dumpdirmap);
10146792Smckusick 		if (dp->di_mtime >= spcl.c_ddate ||
10246792Smckusick 		    dp->di_ctime >= spcl.c_ddate) {
10346792Smckusick 			SETINO(ino, dumpinomap);
10446792Smckusick 			if (mode != IFREG && mode != IFDIR && mode != IFLNK) {
10546792Smckusick 				*tapesize += 1;
10646792Smckusick 				continue;
10746792Smckusick 			}
10846792Smckusick 			*tapesize += blockest(dp);
10946792Smckusick 			continue;
11046792Smckusick 		}
11146792Smckusick 		if (mode == IFDIR)
11246792Smckusick 			anydirskipped = 1;
11346792Smckusick 	}
11446792Smckusick 	/*
11546792Smckusick 	 * Restore gets very upset if the root is not dumped,
11646792Smckusick 	 * so ensure that it always is dumped.
11746792Smckusick 	 */
11846792Smckusick 	SETINO(ROOTINO, usedinomap);
11946792Smckusick 	return (anydirskipped);
12046584Storek }
12146584Storek 
12246792Smckusick /*
12346792Smckusick  * Dump pass 2.
12446792Smckusick  *
12546792Smckusick  * Scan each directory on the filesystem to see if it has any modified
12646792Smckusick  * files in it. If it does, and has not already been added to the dump
12746792Smckusick  * list (because it was itself modified), then add it. If a directory
12846792Smckusick  * has not been modified itself, contains no modified files and has no
12946792Smckusick  * subdirectories, then it can be deleted from the dump list and from
13046792Smckusick  * the list of directories. By deleting it from the list of directories,
13146792Smckusick  * its parent may now qualify for the same treatment on this or a later
13246792Smckusick  * pass using this algorithm.
13346792Smckusick  */
13446792Smckusick mapdirs(maxino, tapesize)
13546792Smckusick 	ino_t maxino;
13646792Smckusick 	long *tapesize;
13746792Smckusick {
13846792Smckusick 	register struct	dinode *dp;
13947058Smckusick 	register int i, dirty;
14025797Smckusick 	register char *map;
14146792Smckusick 	register ino_t ino;
14246792Smckusick 	long filesize, blkcnt = 0;
14346792Smckusick 	int ret, change = 0;
1441426Sroot 
14546792Smckusick 	for (map = dumpdirmap, ino = 0; ino < maxino; ) {
14646584Storek 		if ((ino % NBBY) == 0)
14747058Smckusick 			dirty = *map++;
14846792Smckusick 		else
14947058Smckusick 			dirty >>= 1;
1504702Smckusic 		ino++;
15147058Smckusick 		if ((dirty & 1) == 0 || TSTINO(ino, dumpinomap))
15246792Smckusick 			continue;
15346792Smckusick 		dp = getino(ino);
15446792Smckusick 		filesize = dp->di_size;
15546792Smckusick 		for (ret = 0, i = 0; filesize > 0 && i < NDADDR; i++) {
15646792Smckusick 			if (dp->di_db[i] != 0)
15746792Smckusick 				ret |= searchdir(ino, dp->di_db[i],
15846796Smckusick 					dblksize(sblock, dp, i), filesize);
15946792Smckusick 			if (ret & HASDUMPEDFILE)
16046792Smckusick 				filesize = 0;
16146792Smckusick 			else
16246792Smckusick 				filesize -= sblock->fs_bsize;
16346792Smckusick 		}
16446792Smckusick 		for (i = 0; filesize > 0 && i < NIADDR; i++) {
16546792Smckusick 			if (dp->di_ib[i] == 0)
16646792Smckusick 				continue;
16746792Smckusick 			ret |= dirindir(ino, dp->di_ib[i], i, &filesize);
16846792Smckusick 		}
16946792Smckusick 		if (ret & HASDUMPEDFILE) {
17046792Smckusick 			if (!TSTINO(ino, dumpinomap)) {
17146792Smckusick 				SETINO(ino, dumpinomap);
17246792Smckusick 				*tapesize += blockest(dp);
17346792Smckusick 			}
17446792Smckusick 			change = 1;
17546792Smckusick 			continue;
17646792Smckusick 		}
17746792Smckusick 		if ((ret & HASSUBDIRS) == 0) {
17846792Smckusick 			if (!TSTINO(ino, dumpinomap)) {
17946792Smckusick 				CLRINO(ino, dumpdirmap);
18046792Smckusick 				change = 1;
18146792Smckusick 			}
18246792Smckusick 		}
1831426Sroot 	}
18446792Smckusick 	return (change);
1851426Sroot }
1861426Sroot 
18746792Smckusick /*
18846792Smckusick  * Read indirect blocks, and pass the data blocks to be searched
18946792Smckusick  * as directories. Quit as soon as any entry is found that will
19046792Smckusick  * require the directory to be dumped.
19146792Smckusick  */
19246792Smckusick dirindir(ino, blkno, level, filesize)
19346792Smckusick 	ino_t ino;
19446792Smckusick 	daddr_t blkno;
19546792Smckusick 	int level, *filesize;
1961426Sroot {
19746792Smckusick 	int ret = 0;
19846792Smckusick 	register int i;
19946792Smckusick 	daddr_t	idblk[MAXNINDIR];
2001426Sroot 
20146792Smckusick 	bread(fsbtodb(sblock, blkno), (char *)idblk, sblock->fs_bsize);
20246792Smckusick 	if (level <= 0) {
20346792Smckusick 		for (i = 0; *filesize > 0 && i < NINDIR(sblock); i++) {
20446792Smckusick 			blkno = idblk[i];
20546792Smckusick 			if (blkno != 0)
20646796Smckusick 				ret |= searchdir(ino, blkno, sblock->fs_bsize,
20746796Smckusick 					filesize);
20846792Smckusick 			if (ret & HASDUMPEDFILE)
20946792Smckusick 				*filesize = 0;
21046792Smckusick 			else
21146792Smckusick 				*filesize -= sblock->fs_bsize;
2121426Sroot 		}
21346792Smckusick 		return (ret);
2145329Smckusic 	}
21546792Smckusick 	level--;
21646792Smckusick 	for (i = 0; *filesize > 0 && i < NINDIR(sblock); i++) {
21746792Smckusick 		blkno = idblk[i];
21846792Smckusick 		if (blkno != 0)
21946792Smckusick 			ret |= dirindir(ino, blkno, level, filesize);
2205329Smckusic 	}
22146792Smckusick 	return (ret);
2221426Sroot }
2231426Sroot 
22446792Smckusick /*
22546792Smckusick  * Scan a disk block containing directory information looking to see if
22646792Smckusick  * any of the entries are on the dump list and to see if the directory
22746792Smckusick  * contains any subdirectories.
22846792Smckusick  */
22946796Smckusick searchdir(ino, blkno, size, filesize)
23046792Smckusick 	ino_t ino;
23146792Smckusick 	daddr_t blkno;
23246792Smckusick 	register int size;
23346796Smckusick 	int filesize;
2345329Smckusic {
23546792Smckusick 	register struct direct *dp;
23646792Smckusick 	register long loc;
23746792Smckusick 	char dblk[MAXBSIZE];
2385329Smckusic 
23946792Smckusick 	bread(fsbtodb(sblock, blkno), dblk, size);
24046796Smckusick 	if (filesize < size)
24146796Smckusick 		size = filesize;
24246792Smckusick 	for (loc = 0; loc < size; ) {
24346792Smckusick 		dp = (struct direct *)(dblk + loc);
24446792Smckusick 		if (dp->d_reclen == 0) {
24546792Smckusick 			msg("corrupted directory, inumber %d\n", ino);
24646792Smckusick 			break;
2475329Smckusic 		}
24846792Smckusick 		loc += dp->d_reclen;
24946792Smckusick 		if (dp->d_ino == 0)
25046792Smckusick 			continue;
25146792Smckusick 		if (dp->d_name[0] == '.') {
25246792Smckusick 			if (dp->d_name[1] == '\0')
25346792Smckusick 				continue;
25446792Smckusick 			if (dp->d_name[1] == '.' && dp->d_name[2] == '\0')
25546792Smckusick 				continue;
2565329Smckusic 		}
25746792Smckusick 		if (TSTINO(dp->d_ino, dumpinomap))
25846792Smckusick 			return (HASDUMPEDFILE);
25946792Smckusick 		if (TSTINO(dp->d_ino, dumpdirmap))
26046792Smckusick 			return (HASSUBDIRS);
2615329Smckusic 	}
26246792Smckusick 	return (0);
2635329Smckusic }
2645329Smckusic 
26546792Smckusick /*
26646792Smckusick  * Dump passes 3 and 4.
26746792Smckusick  *
26846792Smckusick  * Dump the contents of an inode to tape.
26946792Smckusick  */
27046584Storek void
27147058Smckusick dumpino(dp, ino)
27247058Smckusick 	register struct dinode *dp;
27346792Smckusick 	ino_t ino;
27417234Smckusick {
27546792Smckusick 	int mode, level, cnt;
2764777Smckusic 	long size;
2771426Sroot 
27846792Smckusick 	if (newtape) {
2791426Sroot 		newtape = 0;
28046792Smckusick 		dumpmap(dumpinomap, TS_BITS, ino);
2811426Sroot 	}
28246792Smckusick 	CLRINO(ino, dumpinomap);
28347058Smckusick 	spcl.c_dinode = *dp;
2841426Sroot 	spcl.c_type = TS_INODE;
2851426Sroot 	spcl.c_count = 0;
28646792Smckusick 	/*
28746792Smckusick 	 * Check for freed inode.
28846792Smckusick 	 */
28947058Smckusick 	if ((mode = (dp->di_mode & IFMT)) == 0)
29017234Smckusick 		return;
29146792Smckusick 	if ((mode != IFDIR && mode != IFREG && mode != IFLNK) ||
29247058Smckusick 	    dp->di_size == 0) {
29346792Smckusick 		writeheader(ino);
2941426Sroot 		return;
2951426Sroot 	}
29647058Smckusick 	if (dp->di_size > NDADDR * sblock->fs_bsize)
29746792Smckusick 		cnt = NDADDR * sblock->fs_frag;
2984777Smckusic 	else
29947058Smckusick 		cnt = howmany(dp->di_size, sblock->fs_fsize);
30047058Smckusick 	blksout(&dp->di_db[0], cnt, ino);
30147058Smckusick 	if ((size = dp->di_size - NDADDR * sblock->fs_bsize) <= 0)
3024777Smckusic 		return;
30346792Smckusick 	for (level = 0; level < NIADDR; level++) {
30447058Smckusick 		dmpindir(ino, dp->di_ib[level], level, &size);
3054777Smckusic 		if (size <= 0)
3064777Smckusic 			return;
3074777Smckusic 	}
3081426Sroot }
3091426Sroot 
31046792Smckusick /*
31146792Smckusick  * Read indirect blocks, and pass the data blocks to be dumped.
31246792Smckusick  */
31346584Storek void
31446792Smckusick dmpindir(ino, blk, level, size)
31546792Smckusick 	ino_t ino;
3164777Smckusic 	daddr_t blk;
31746792Smckusick 	int level;
3184777Smckusic 	long *size;
3191426Sroot {
3204777Smckusic 	int i, cnt;
3215329Smckusic 	daddr_t idblk[MAXNINDIR];
3221426Sroot 
3234777Smckusic 	if (blk != 0)
3245329Smckusic 		bread(fsbtodb(sblock, blk), (char *)idblk, sblock->fs_bsize);
3254777Smckusic 	else
32646584Storek 		bzero((char *)idblk, sblock->fs_bsize);
32746792Smckusick 	if (level <= 0) {
3285329Smckusic 		if (*size < NINDIR(sblock) * sblock->fs_bsize)
3295329Smckusic 			cnt = howmany(*size, sblock->fs_fsize);
3304777Smckusic 		else
3315329Smckusic 			cnt = NINDIR(sblock) * sblock->fs_frag;
3325329Smckusic 		*size -= NINDIR(sblock) * sblock->fs_bsize;
33346792Smckusick 		blksout(&idblk[0], cnt, ino);
3344777Smckusic 		return;
3351426Sroot 	}
33646792Smckusick 	level--;
3375329Smckusic 	for (i = 0; i < NINDIR(sblock); i++) {
33846792Smckusick 		dmpindir(ino, idblk[i], level, size);
3394777Smckusic 		if (*size <= 0)
3404777Smckusic 			return;
3414777Smckusic 	}
3421426Sroot }
3431426Sroot 
34446792Smckusick /*
34546792Smckusick  * Collect up the data into tape record sized buffers and output them.
34646792Smckusick  */
34746584Storek void
34846792Smckusick blksout(blkp, frags, ino)
3494777Smckusic 	daddr_t *blkp;
3504777Smckusic 	int frags;
35146792Smckusick 	ino_t ino;
3524777Smckusic {
35346584Storek 	register daddr_t *bp;
3545329Smckusic 	int i, j, count, blks, tbperdb;
3554777Smckusic 
3569403Smckusick 	blks = howmany(frags * sblock->fs_fsize, TP_BSIZE);
35746584Storek 	tbperdb = sblock->fs_bsize >> tp_bshift;
3584777Smckusic 	for (i = 0; i < blks; i += TP_NINDIR) {
3594777Smckusic 		if (i + TP_NINDIR > blks)
3604777Smckusic 			count = blks;
3614777Smckusic 		else
3624777Smckusic 			count = i + TP_NINDIR;
3634777Smckusic 		for (j = i; j < count; j++)
3645329Smckusic 			if (blkp[j / tbperdb] != 0)
3654777Smckusic 				spcl.c_addr[j - i] = 1;
3664777Smckusic 			else
3674777Smckusic 				spcl.c_addr[j - i] = 0;
3684777Smckusic 		spcl.c_count = count - i;
36946792Smckusick 		writeheader(ino);
37046584Storek 		bp = &blkp[i / tbperdb];
37146584Storek 		for (j = i; j < count; j += tbperdb, bp++)
37246584Storek 			if (*bp != 0)
3735329Smckusic 				if (j + tbperdb <= count)
37446792Smckusick 					dumpblock(*bp, sblock->fs_bsize);
3754777Smckusic 				else
37646792Smckusick 					dumpblock(*bp, (count - j) * TP_BSIZE);
3774777Smckusic 		spcl.c_type = TS_ADDR;
3784777Smckusic 	}
3794777Smckusic }
3804777Smckusic 
38146792Smckusick /*
38246792Smckusick  * Dump a map to the tape.
38346792Smckusick  */
38446584Storek void
38546792Smckusick dumpmap(map, type, ino)
3865329Smckusic 	char *map;
38746792Smckusick 	int type;
38846792Smckusick 	ino_t ino;
3891426Sroot {
39046792Smckusick 	register int i;
3911426Sroot 	char *cp;
3921426Sroot 
39346792Smckusick 	spcl.c_type = type;
39446792Smckusick 	spcl.c_count = howmany(mapsize * sizeof(char), TP_BSIZE);
39546792Smckusick 	writeheader(ino);
3965329Smckusic 	for (i = 0, cp = map; i < spcl.c_count; i++, cp += TP_BSIZE)
39746792Smckusick 		writerec(cp);
3981426Sroot }
3991426Sroot 
40046792Smckusick /*
40146792Smckusick  * Write a header record to the dump tape.
40246792Smckusick  */
40346584Storek void
40446792Smckusick writeheader(ino)
40546792Smckusick 	ino_t ino;
4061426Sroot {
40746792Smckusick 	register long sum, cnt, *lp;
4081426Sroot 
4091426Sroot 	spcl.c_inumber = ino;
4108368Smckusick 	spcl.c_magic = NFS_MAGIC;
4111426Sroot 	spcl.c_checksum = 0;
41246792Smckusick 	lp = (long *)&spcl;
41346792Smckusick 	sum = 0;
41446792Smckusick 	cnt = sizeof(union u_spcl) / (4 * sizeof(long));
41546792Smckusick 	while (--cnt >= 0) {
41646792Smckusick 		sum += *lp++;
41746792Smckusick 		sum += *lp++;
41846792Smckusick 		sum += *lp++;
41946792Smckusick 		sum += *lp++;
42024168Smckusick 	}
42146792Smckusick 	spcl.c_checksum = CHECKSUM - sum;
42246792Smckusick 	writerec((char *)&spcl);
4231426Sroot }
4241426Sroot 
4254702Smckusic struct dinode *
42646792Smckusick getino(inum)
42746792Smckusick 	ino_t inum;
4284702Smckusic {
4294702Smckusic 	static daddr_t minino, maxino;
43046792Smckusick 	static struct dinode inoblock[MAXINOPB];
4314702Smckusic 
43246792Smckusick 	curino = inum;
43346792Smckusick 	if (inum >= minino && inum < maxino)
43446792Smckusick 		return (&inoblock[inum - minino]);
43546792Smckusick 	bread(fsbtodb(sblock, itod(sblock, inum)), inoblock, sblock->fs_bsize);
43646792Smckusick 	minino = inum - (inum % INOPB(sblock));
4375329Smckusic 	maxino = minino + INOPB(sblock);
43846792Smckusick 	return (&inoblock[inum - minino]);
4394702Smckusic }
4404702Smckusic 
44146792Smckusick /*
44246792Smckusick  * Read a chunk of data from the disk.
44346792Smckusick  * Try to recover from hard errors by reading in sector sized pieces.
44446792Smckusick  * Error recovery is attempted at most BREADEMAX times before seeking
44546792Smckusick  * consent from the operator to continue.
44646792Smckusick  */
4471426Sroot int	breaderrors = 0;
4481426Sroot #define	BREADEMAX 32
4491426Sroot 
45046584Storek void
45146792Smckusick bread(blkno, buf, size)
45246792Smckusick 	daddr_t blkno;
45346792Smckusick 	char *buf;
45446792Smckusick 	int size;
4551426Sroot {
45646792Smckusick 	int cnt, i;
45734359Skarels 	extern int errno;
4581426Sroot 
45915095Smckusick loop:
46046792Smckusick 	if (lseek(diskfd, (long)(blkno << dev_bshift), 0) < 0)
4611426Sroot 		msg("bread: lseek fails\n");
46246792Smckusick 	if ((cnt = read(diskfd, buf, size)) == size)
46315095Smckusick 		return;
46446792Smckusick 	if (blkno + (size / dev_bsize) > fsbtodb(sblock, sblock->fs_size)) {
46515095Smckusick 		/*
46615095Smckusick 		 * Trying to read the final fragment.
46715095Smckusick 		 *
46815095Smckusick 		 * NB - dump only works in TP_BSIZE blocks, hence
46930560Smckusick 		 * rounds `dev_bsize' fragments up to TP_BSIZE pieces.
47015095Smckusick 		 * It should be smarter about not actually trying to
47115095Smckusick 		 * read more than it can get, but for the time being
47215095Smckusick 		 * we punt and scale back the read only when it gets
47315095Smckusick 		 * us into trouble. (mkm 9/25/83)
47415095Smckusick 		 */
47546792Smckusick 		size -= dev_bsize;
47615095Smckusick 		goto loop;
4771426Sroot 	}
478*50905Smckusick 	if (cnt == -1)
479*50905Smckusick 		msg("read error from %s: %s: [block %d]: count=%d\n",
480*50905Smckusick 			disk, strerror(errno), blkno, size);
481*50905Smckusick 	else
482*50905Smckusick 		msg("short read error from %s: [block %d]: count=%d, got=%d\n",
483*50905Smckusick 			disk, blkno, size, cnt);
48446584Storek 	if (++breaderrors > BREADEMAX) {
48515095Smckusick 		msg("More than %d block read errors from %d\n",
48615095Smckusick 			BREADEMAX, disk);
48715095Smckusick 		broadcast("DUMP IS AILING!\n");
48815095Smckusick 		msg("This is an unrecoverable error.\n");
48915095Smckusick 		if (!query("Do you want to attempt to continue?")){
49015095Smckusick 			dumpabort();
49115095Smckusick 			/*NOTREACHED*/
49215095Smckusick 		} else
49315095Smckusick 			breaderrors = 0;
49415095Smckusick 	}
49534359Skarels 	/*
49634359Skarels 	 * Zero buffer, then try to read each sector of buffer separately.
49734359Skarels 	 */
49846792Smckusick 	bzero(buf, size);
49946792Smckusick 	for (i = 0; i < size; i += dev_bsize, buf += dev_bsize, blkno++) {
50046792Smckusick 		if (lseek(diskfd, (long)(blkno << dev_bshift), 0) < 0)
50134359Skarels 			msg("bread: lseek2 fails!\n");
502*50905Smckusick 		if ((cnt = read(diskfd, buf, dev_bsize)) == dev_bsize)
503*50905Smckusick 			continue;
504*50905Smckusick 		if (cnt == -1) {
505*50905Smckusick 			msg("read error from %s: %s: [sector %d]: count=%d\n",
506*50905Smckusick 				disk, strerror(errno), blkno, dev_bsize);
507*50905Smckusick 			continue;
508*50905Smckusick 		}
509*50905Smckusick 		msg("short read error from %s: [sector %d]: count=%d, got=%d\n",
510*50905Smckusick 			disk, blkno, dev_bsize, cnt);
51134359Skarels 	}
5121426Sroot }
513