genhd.c

基于组件方式开发操作系统的OSKIT源代码

		printk(" unable to read partition table\n");
		return -1;
	}
	data = bh->b_data;
	/* In some cases we modify the geometry    */
	/*  of the drive (below), so ensure that   */
	/*  nobody else tries to re-use this data. */
	bh->b_state = 0;
#ifdef CONFIG_BLK_DEV_IDE
check_table:
#endif
	if (*(unsigned short *)  (0x1fe + data) != cpu_to_le16(MSDOS_LABEL_MAGIC)) {
		brelse(bh);
		return 0;
	}
	p = (struct partition *) (0x1be + data);

#ifdef CONFIG_BLK_DEV_IDE
	if (!tested_for_xlate++) {	/* Do this only once per disk */
		/*
		 * Look for various forms of IDE disk geometry translation
		 */
		extern int ide_xlate_1024(kdev_t, int, const char *);
		unsigned int sig = le16_to_cpu(*(unsigned short *)(data + 2));
		if (SYS_IND(p) == EZD_PARTITION) {
			/*
			 * The remainder of the disk must be accessed using
			 * a translated geometry that reduces the number of 
			 * apparent cylinders to less than 1024 if possible.
			 *
			 * ide_xlate_1024() will take care of the necessary
			 * adjustments to fool fdisk/LILO and partition check.
			 */
			if (ide_xlate_1024(dev, -1, " [EZD]")) {
				data += 512;
				goto check_table;
			}
		} else if (SYS_IND(p) == DM6_PARTITION) {

			/*
			 * Everything on the disk is offset by 63 sectors,
			 * including a "new" MBR with its own partition table,
			 * and the remainder of the disk must be accessed using
			 * a translated geometry that reduces the number of 
			 * apparent cylinders to less than 1024 if possible.
			 *
			 * ide_xlate_1024() will take care of the necessary
			 * adjustments to fool fdisk/LILO and partition check.
			 */
			if (ide_xlate_1024(dev, 1, " [DM6:DDO]")) {
				brelse(bh);
				goto read_mbr;	/* start over with new MBR */
			}
		} else if (sig <= 0x1ae &&
			   *(unsigned short *)(data + sig) == cpu_to_le16(0x55AA) &&
			   (1 & *(unsigned char *)(data + sig + 2))) {
			/* DM6 signature in MBR, courtesy of OnTrack */
			(void) ide_xlate_1024 (dev, 0, " [DM6:MBR]");
		} else if (SYS_IND(p) == DM6_AUX1PARTITION || SYS_IND(p) == DM6_AUX3PARTITION) {
			/*
			 * DM6 on other than the first (boot) drive
			 */
			(void) ide_xlate_1024(dev, 0, " [DM6:AUX]");
		} else {
			/*
			 * Examine the partition table for common translations.
			 * This is useful for drives in situations where the
			 * translated geometry is unavailable from the BIOS.
			 */
			for (i = 0; i < 4; i++) {
				struct partition *q = &p[i];
				if (NR_SECTS(q)
				   && (q->sector & 63) == 1
				   && (q->end_sector & 63) == 63) {
					unsigned int heads = q->end_head + 1;
					if (heads == 32 || heads == 64 ||
					    heads == 128 || heads == 240 ||
					    heads == 255) {
						(void) ide_xlate_1024(dev, heads, " [PTBL]");
						break;
					}
				}
			}
		}
	}
#endif	/* CONFIG_BLK_DEV_IDE */

	current_minor += 4;  /* first "extra" minor (for extended partitions) */
	for (i=1 ; i<=4 ; minor++,i++,p++) {
		if (!NR_SECTS(p))
			continue;
               add_partition(hd, minor, first_sector+START_SECT(p)*sector_size, NR_SECTS(p)*sector_size, 
               		     ptype(SYS_IND(p)));
		if (is_extended_partition(p)) {
			printk(" <");
			/*
			 * If we are rereading the partition table, we need
			 * to set the size of the partition so that we will
			 * be able to bread the block containing the extended
			 * partition info.
			 */
			hd->sizes[minor] = hd->part[minor].nr_sects 
			  	>> (BLOCK_SIZE_BITS - 9);
			extended_partition(hd, MKDEV(hd->major, minor));
			printk(" >");
			/* prevent someone doing mkfs or mkswap on an
			   extended partition, but leave room for LILO */
			if (hd->part[minor].nr_sects > 2)
				hd->part[minor].nr_sects = 2;
		}
#ifdef CONFIG_BSD_DISKLABEL
			/* tag first disklabel for late recognition */
		if (SYS_IND(p) == BSD_PARTITION || SYS_IND(p) == NETBSD_PARTITION) {
			printk("!");
			if (!bsd_kdev)
				bsd_kdev = MKDEV(hd->major, minor);
		} else if (SYS_IND(p) == OPENBSD_PARTITION) {
			printk("!");
			if (!bsd_kdev) {
				bsd_kdev = MKDEV(hd->major, minor);
				bsd_maxpart = OPENBSD_MAXPARTITIONS;
			}
		}
#endif
#ifdef CONFIG_UNIXWARE_DISKLABEL
		if (SYS_IND(p) == UNIXWARE_PARTITION)
			unixware_partition(hd, MKDEV(hd->major, minor));
#endif
#ifdef CONFIG_SOLARIS_X86_PARTITION

		/* [e-mail]: Solaris has a nasty indicator: 0x82
		 * which also means linux swap.  For that reason, all
		 * of the prints are done inside the
		 * solaris_x86_partition routine */

		if(SYS_IND(p) == SOLARIS_X86_PARTITION) {
			solaris_x86_partition(hd, MKDEV(hd->major, minor),
					      first_sector+START_SECT(p));
		}
#endif
	}
#ifdef CONFIG_BSD_DISKLABEL
	if (bsd_kdev) {
		printk(" <");
		bsd_disklabel_partition(hd, bsd_kdev, bsd_maxpart);
		printk(" >");
	}
#endif
	/*
	 *  Check for old-style Disk Manager partition table
	 */
	if (*(unsigned short *) (data+0xfc) == cpu_to_le16(MSDOS_LABEL_MAGIC)) {
		p = (struct partition *) (0x1be + data);
		for (i = 4 ; i < 16 ; i++, current_minor++) {
			p--;
			if ((current_minor & mask) == 0)
				break;
			if (!(START_SECT(p) && NR_SECTS(p)))
				continue;
			add_partition(hd, current_minor, START_SECT(p),
					NR_SECTS(p), 0);
		}
	}
	printk("\n");
	brelse(bh);
	return 1;
}

#endif /* CONFIG_MSDOS_PARTITION */

#ifdef CONFIG_OSF_PARTITION

static int osf_partition(struct gendisk *hd, unsigned int dev, unsigned long first_sector)
{
	int i;
	int mask = (1 << hd->minor_shift) - 1;
	struct buffer_head *bh;
	struct disklabel {
		u32 d_magic;
		u16 d_type,d_subtype;
		u8 d_typename[16];
		u8 d_packname[16];
		u32 d_secsize;
		u32 d_nsectors;
		u32 d_ntracks;
		u32 d_ncylinders;
		u32 d_secpercyl;
		u32 d_secprtunit;
		u16 d_sparespertrack;
		u16 d_sparespercyl;
		u32 d_acylinders;
		u16 d_rpm, d_interleave, d_trackskew, d_cylskew;
		u32 d_headswitch, d_trkseek, d_flags;
		u32 d_drivedata[5];
		u32 d_spare[5];
		u32 d_magic2;
		u16 d_checksum;
		u16 d_npartitions;
		u32 d_bbsize, d_sbsize;
		struct d_partition {
			u32 p_size;
			u32 p_offset;
			u32 p_fsize;
			u8  p_fstype;
			u8  p_frag;
			u16 p_cpg;
		} d_partitions[8];
	} * label;
	struct d_partition * partition;
#define DISKLABELMAGIC (0x82564557UL)

	if (!(bh = bread(dev,0,get_ptable_blocksize(dev)))) {
		printk("unable to read partition table\n");
		return -1;
	}
	label = (struct disklabel *) (bh->b_data+64);
	partition = label->d_partitions;
	if (label->d_magic != DISKLABELMAGIC) {
		brelse(bh);
		return 0;
	}
	if (label->d_magic2 != DISKLABELMAGIC) {
		brelse(bh);
		return 0;
	}
	for (i = 0 ; i < label->d_npartitions; i++, partition++) {
		if ((current_minor & mask) == 0)
		        break;
		if (partition->p_size)
			add_partition(hd, current_minor,
				first_sector+partition->p_offset,
				partition->p_size, 0);
		current_minor++;
	}
	printk("\n");
	brelse(bh);
	return 1;
}

#endif /* CONFIG_OSF_PARTITION */

#ifdef CONFIG_SUN_PARTITION

static int sun_partition(struct gendisk *hd, kdev_t dev, unsigned long first_sector)
{
	int i, csum;
	unsigned short *ush;
	struct buffer_head *bh;
	struct sun_disklabel {
		unsigned char info[128];   /* Informative text string */
		unsigned char spare0[14];
		struct sun_disklabelinfo {
			unsigned char spare1;
			unsigned char id;
			unsigned char spare2;
			unsigned char flags;
		} infos[8];
		unsigned char spare1[246];  /* Boot information etc. */
		unsigned short rspeed;     /* Disk rotational speed */
		unsigned short pcylcount;  /* Physical cylinder count */
		unsigned short sparecyl;   /* extra sects per cylinder */
		unsigned char spare2[4];   /* More magic... */
		unsigned short ilfact;     /* Interleave factor */
		unsigned short ncyl;       /* Data cylinder count */
		unsigned short nacyl;      /* Alt. cylinder count */
		unsigned short ntrks;      /* Tracks per cylinder */
		unsigned short nsect;      /* Sectors per track */
		unsigned char spare3[4];   /* Even more magic... */
		struct sun_partition {
			__u32 start_cylinder;
			__u32 num_sectors;
		} partitions[8];
		unsigned short magic;      /* Magic number */
		unsigned short csum;       /* Label xor'd checksum */
	} * label;		
	struct sun_partition *p;
	unsigned long spc;
#define SUN_LABEL_MAGIC          0xDABE

	if(!(bh = bread(dev, 0, get_ptable_blocksize(dev)))) {
		printk("Dev %s: unable to read partition table\n",
		       kdevname(dev));
		return -1;
	}
	label = (struct sun_disklabel *) bh->b_data;
	p = label->partitions;
	if (be16_to_cpu(label->magic) != SUN_LABEL_MAGIC) {
		printk("Dev %s Sun disklabel: bad magic %04x\n",
		       kdevname(dev), be16_to_cpu(label->magic));
		brelse(bh);
		return 0;
	}
	/* Look at the checksum */
	ush = ((unsigned short *) (label+1)) - 1;
	for(csum = 0; ush >= ((unsigned short *) label);)
		csum ^= *ush--;
	if(csum) {
		printk("Dev %s Sun disklabel: Csum bad, label corrupted\n",
		       kdevname(dev));
		brelse(bh);
		return 0;
	}
	/* All Sun disks have 8 partition entries */
	spc = be16_to_cpu(label->ntrks) * be16_to_cpu(label->nsect);
	for(i=0; i < 8; i++, p++) {
		unsigned long st_sector;
		int num_sectors;

		st_sector = first_sector + be32_to_cpu(p->start_cylinder) * spc;
		num_sectors = be32_to_cpu(p->num_sectors);
		if (num_sectors)
			add_partition(hd, current_minor, st_sector,
					num_sectors, ptype(label->infos[i].id));
		current_minor++;
	}
	printk("\n");
	brelse(bh);
	return 1;
}

#endif /* CONFIG_SUN_PARTITION */

#ifdef CONFIG_SGI_PARTITION

static int sgi_partition(struct gendisk *hd, kdev_t dev, unsigned long first_sector)
{
	int i, csum, magic;
	unsigned int *ui, start, blocks, cs;
	struct buffer_head *bh;
	struct sgi_disklabel {
		int magic_mushroom;         /* Big fat spliff... */
		short root_part_num;        /* Root partition number */
		short swap_part_num;        /* Swap partition number */
		char boot_file[16];         /* Name of boot file for ARCS */
		unsigned char _unused0[48]; /* Device parameter useless crapola.. */
		struct sgi_volume {
			char name[8];       /* Name of volume */
			int  block_num;     /* Logical block number */
			int  num_bytes;     /* How big, in bytes */
		} volume[15];
		struct sgi_partition {
			int num_blocks;     /* Size in logical blocks */
			int first_block;    /* First logical block */
			int type;           /* Type of this partition */
		} partitions[16];
		int csum;                   /* Disk label checksum */
		int _unused1;               /* Padding */
	} *label;
	struct sgi_partition *p;
#define SGI_LABEL_MAGIC 0x0be5a941

	if(!(bh = bread(dev, 0, get_ptable_blocksize(dev)))) {
		printk("Dev %s: unable to read partition table\n", kdevname(dev));
		return -1;
	}
	label = (struct sgi_disklabel *) bh->b_data;
	p = &label->partitions[0];
	magic = label->magic_mushroom;
	if(be32_to_cpu(magic) != SGI_LABEL_MAGIC) {
		printk("Dev %s SGI disklabel: bad magic %08x\n",
		       kdevname(dev), magic);
		brelse(bh);
		return 0;
	}
	ui = ((unsigned int *) (label + 1)) - 1;
	for(csum = 0; ui >= ((unsigned int *) label);) {
		cs = *ui--;
		csum += be32_to_cpu(cs);
	}
	if(csum) {
		printk("Dev %s SGI disklabel: csum bad, label corrupted\n",
		       kdevname(dev));
		brelse(bh);
		return 0;
	}
	/* All SGI disk labels have 16 partitions, disks under Linux only
	 * have 15 minor's.  Luckily there are always a few zero length
	 * partitions which we don't care about so we never overflow the
	 * current_minor.
	 */
	for(i = 0; i < 16; i++, p++) {
		blocks = be32_to_cpu(p->num_blocks);
		start  = be32_to_cpu(p->first_block);
		if(!blocks)
			continue;
		add_partition(hd, current_minor, start, blocks, 0);
		current_minor++;
	}
	printk("\n");
	brelse(bh);
	return 1;
}

#endif

#ifdef CONFIG_AMIGA_PARTITION
#include <linux/affs_hardblocks.h>

static __inline__ u32
checksum_block(u32 *m, int size)
{
	u32 sum = 0;

	while (size--)
		sum += htonl(*m++);
	return sum;
}

static int
amiga_partition(struct gendisk *hd, kdev_t dev, unsigned long first_sector)
{
	struct buffer_head	*bh;
	struct RigidDiskBlock	*rdb;
	struct PartitionBlock	*pb;
	int			 start_sect;
	int			 nr_sects;
	int			 blk;
	int			 part, res;
	int			 old_blocksize;
	int			 blocksize;

	old_blocksize = get_ptable_blocksize(dev);
	if (hardsect_size[MAJOR(dev)] != NULL)
		blocksize = hardsect_size[MAJOR(dev)][MINOR(dev)];
	else
		blocksize = 512;

	set_blocksize(dev,blocksize);
	res = 0;

	for (blk = 0; blk < RDB_ALLOCATION_LIMIT; blk++) {
		if(!(bh = bread(dev,blk,blocksize))) {
			printk("Dev %s: unable to read RDB block %d\n",
			       kdevname(dev),blk);
			goto rdb_done;
		}
		if (*(u32 *)bh->b_data == htonl(IDNAME_RIGIDDISK)) {
			rdb = (struct RigidDiskBlock *)bh->b_data;
			if (checksum_block((u32 *)bh->b_data,htonl(rdb->rdb_SummedLongs) & 0x7F)) {
				/* Try again with 0xdc..0xdf zeroed, Windows might have
				 * trashed it.
				 */
				*(u32 *)(&bh->b_data[0xdc]) = 0;
				if (checksum_block((u32 *)bh->b_data,
						htonl(rdb->rdb_SummedLongs) & 0x7F)) {
					brelse(bh);
					printk("Dev %s: RDB in block %d has bad checksum\n",
					       kdevname(dev),blk);
					continue;
				}
				printk("Warning: Trashed word at 0xd0 in block %d "
					"ignored in checksum calculation\n",blk);
			}
			printk(" RDSK");
			blk = htonl(rdb->rdb_PartitionList);
			brelse(bh);
			for (part = 1; blk > 0 && part <= 16; part++) {
				if (!(bh = bread(dev,blk,blocksize))) {
					printk("Dev %s: unable to read partition block %d\n",
						       kdevname(dev),blk);
					goto rdb_done;
				}
				pb  = (struct PartitionBlock *)bh->b_data;
				blk = htonl(pb->pb_Next);
				if (pb->pb_ID == htonl(IDNAME_PARTITION) && checksum_block(
				    (u32 *)pb,htonl(pb->pb_SummedLongs) & 0x7F) == 0 ) {

					/* Tell Kernel about it */

					if (!(nr_sects = (htonl(pb->pb_Environment[10]) + 1 -
							  htonl(pb->pb_Environment[9])) *
							 htonl(pb->pb_Environment[3]) *
							 htonl(pb->pb_Environment[5]))) {
						brelse(bh);
						continue;
					}
					start_sect = htonl(pb->pb_Environment[9]) *
						     htonl(pb->pb_Environment[3]) *
						     htonl(pb->pb_Environment[5]);
					add_partition(hd,current_minor,
							start_sect,nr_sects,0);
					current_minor++;
					res = 1;
				}
				brelse(bh);
			}
			printk("\n");
		}
		else
			brelse(bh);
	}

rdb_done:
	set_blocksize(dev,old_blocksize);
	return res;
}
#endif /* CONFIG_AMIGA_PARTITION */

#ifdef CONFIG_MAC_PARTITION