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readufs_lfs.c revision 1.1 
      1 /*	$Id: readufs_lfs.c,v 1.1 2001/09/27 10:14:50 minoura Exp $	*/
      2 
      3 /*
      4  * FS specific support for 4.4BSD Log-structured Filesystem
      5  *
      6  * Written by ITOH, Yasufumi (itohy (at) netbsd.org).
      7  * Public domain.
      8  *
      9  * Intended to be used for boot programs (first stage).
     10  * DON'T ADD ANY FANCY FEATURE.  THIS SHALL BE COMPACT.
     11  */
     12 
     13 #include <sys/types.h>
     14 #include <sys/param.h>
     15 #include <sys/mount.h>
     16 #include <ufs/ufs/dinode.h>
     17 #include <ufs/lfs/lfs.h>
     18 
     19 #include "readufs.h"
     20 
     21 static int get_lfs_inode __P((ino_t ino, struct dinode *dibuf));
     22 
     23 static struct dinode	ifile_dinode;
     24 
     25 #define fsi	(*ufsinfo)
     26 #define fsi_lfs	fsi.fs_u.u_lfs
     27 
     28 /*
     29  * Read and check superblock.
     30  * If it is an LFS, save information from the superblock.
     31  */
     32 int
     33 try_lfs()
     34 {
     35 	struct ufs_info *ufsinfo = &ufs_info;
     36 	struct dlfs	sblk, sblk2;
     37 	struct dlfs	*s = &sblk;
     38 
     39 #ifdef DEBUG_WITH_STDIO
     40 	printf("trying LFS\n");
     41 #endif
     42 	/* read primary superblock */
     43 	RAW_READ(&sblk, btodb(LFS_LABELPAD), sizeof sblk);
     44 
     45 #ifdef DEBUG_WITH_STDIO
     46 	printf("LFS: sblk: magic: 0x%x, version: %d\n",
     47 		sblk.dlfs_magic, sblk.dlfs_version);
     48 #endif
     49 
     50 	if (sblk.dlfs_magic != LFS_MAGIC)
     51 		return 1;
     52 
     53 #ifdef DEBUG_WITH_STDIO
     54 	printf("sboff[1]: %d\n", sblk.dlfs_sboffs[1]);
     55 #endif
     56 
     57 	if (sblk.dlfs_sboffs[1] > 0) {
     58 		/* read secondary superblock */
     59 		RAW_READ(&sblk2,
     60 			 (unsigned int) sblk.dlfs_sboffs[1], sizeof sblk2);
     61 
     62 #ifdef DEBUG_WITH_STDIO
     63 		printf("LFS: sblk2: magic: 0x%x, version: %d\n",
     64 			sblk2.dlfs_magic, sblk2.dlfs_version);
     65 #endif
     66 
     67 		if (sblk2.dlfs_magic == LFS_MAGIC &&
     68 		    sblk.dlfs_tstamp > sblk2.dlfs_tstamp)
     69 			s = &sblk2;
     70 	}
     71 
     72 	/* This partition looks like an LFS. */
     73 	fsi.get_inode = get_lfs_inode;
     74 	/* Disk addr in inode is in disk sector --- no shifting. */
     75 	fsi.iblkshift = 0;
     76 
     77 	/* Get information from the superblock. */
     78 	fsi.bsize = s->dlfs_bsize;
     79 	fsi.fsbtodb = s->dlfs_fsbtodb;
     80 	fsi.nindir = s->dlfs_nindir;
     81 
     82 	fsi_lfs.idaddr = s->dlfs_idaddr;
     83 	fsi_lfs.inopb = s->dlfs_inopb;
     84 	fsi_lfs.ifpb = s->dlfs_ifpb;
     85 	fsi_lfs.cleansz = s->dlfs_cleansz;
     86 	fsi_lfs.segtabsz = s->dlfs_segtabsz;
     87 
     88 	/* ifile is always used to look-up other inodes, so keep its inode. */
     89 	if (get_lfs_inode(LFS_IFILE_INUM, &ifile_dinode))
     90 		return 1;	/* OOPS, failed to find inode of ifile! */
     91 
     92 	fsi.fstype = UFSTYPE_LFS;
     93 
     94 	return 0;
     95 }
     96 
     97 /*
     98  * Get inode from disk.
     99  */
    100 static int
    101 get_lfs_inode(ino, dibuf)
    102 	ino_t ino;
    103 	struct dinode *dibuf;
    104 {
    105 	struct ufs_info *ufsinfo = &ufs_info;
    106 	ufs_daddr_t daddr;
    107 	char *buf = alloca(fsi.bsize);
    108 	struct dinode *di;
    109 	int cnt;
    110 
    111 	/* Get fs block which contains the specified inode. */
    112 	if (ino == LFS_IFILE_INUM)
    113 		daddr = fsi_lfs.idaddr;
    114 	else {
    115 #ifdef DEBUG_WITH_STDIO
    116 	printf("LFS: ino: %d\nifpb: %d, cleansz: %d, segtabsz: %d, bsize: %d\n",
    117 	    ino, fsi_lfs.ifpb, fsi_lfs.cleansz, fsi_lfs.segtabsz, fsi.bsize);
    118 #endif
    119 		ufs_read(&ifile_dinode, buf,
    120 			 ino / fsi_lfs.ifpb + fsi_lfs.cleansz +
    121 				fsi_lfs.segtabsz,
    122 			 fsi.bsize);
    123 		daddr = ((IFILE *) buf + ino % fsi_lfs.ifpb)->if_daddr;
    124 	}
    125 #ifdef DEBUG_WITH_STDIO
    126 	printf("LFS(%d): daddr: %d\n", ino, daddr);
    127 #endif
    128 
    129 	if (daddr == LFS_UNUSED_DADDR)
    130 		return 1;
    131 
    132 	/* Read the inode block. */
    133 	RAW_READ(buf, (unsigned int) daddr, fsi.bsize);
    134 
    135 	/* Search for the inode. */
    136 	cnt = fsi_lfs.inopb;
    137 	di = (struct dinode *) buf + (cnt - 1);
    138 
    139 	for ( ; cnt--; di--)
    140 		if (di->di_inumber == ino)
    141 			goto found;
    142 	/* not found */
    143 	return 1;
    144 
    145 found:
    146 #ifdef DEBUG_WITH_STDIO
    147 	printf("LFS: dinode(%d): mode 0%o, nlink %d, inumber %d, size %d, uid %d, gid %d, db[0] %d\n",
    148 		ino, di->di_mode, di->di_nlink, di->di_inumber,
    149 		(int)di->di_size, di->di_uid, di->di_gid, di->di_db[0]);
    150 #endif
    151 
    152 	*dibuf = *di;
    153 
    154 	return 0;
    155 }
    156