hptraid.c

来自「linux-2.4.29操作系统的源码」· C语言 代码 · 共 921 行 · 第 1/2 页

		/* If this ever fails we're doomed */
		if (!bh1)
			BUG();
	
		/*
		 * dupe the bufferhead and update the parts that need to be
		 * different
		 */
		memcpy(bh1, bh, sizeof(*bh));
		
		bh1->b_end_io = ataraid_end_request;
		bh1->b_private = private;
		bh1->b_rsector += ataraid_gendisk.part[MINOR(bh->b_rdev)].start_sect; /* partition offset */
		bh1->b_rdev = raid[device].disk[i].device;

		/* update the last known head position for the drive */
		raid[device].disk[i].last_pos = bh1->b_rsector+(bh1->b_size>>9);

		if( raid[device].raid01 ) {
			if( hptraid0_compute_request(
						raid[device].raid01 +
							(bh1->b_rdev-1),
						q, rw, bh1) != 1 ) {
				/*
				 * If a split is requested then it is requested
				 * in the first iteration. This is true because
				 * of the cutoff is not used in raid 0+1.
				 */
				if(unlikely(i)) {
					BUG();
				}
				else {
					kfree(private);
					return -1;
				}
			}
		}
		generic_make_request(rw,bh1);
	}
	return 0;
}

static int hptraid1_make_request (request_queue_t *q, int rw, struct buffer_head * bh) {
	/*
	 * Read and Write are totally different cases; split them totally
	 * here
	 */
	if (rw==READA)
		rw = READ;
	
	if (rw==READ)
		return hptraid1_read_request(q,rw,bh);
	else
		return hptraid1_write_request(q,rw,bh);
}

static int hptraid01_read_request (request_queue_t *q, int rw, struct buffer_head * bh)
{
	int rsector=bh->b_rsector;
	int rdev=bh->b_rdev;

		/* select mirror volume */
	hptraid1_read_request(q, rw, bh);

		/* stripe volume is selected by "bh->b_rdev" */
	if( hptraid0_compute_request(
				raid[(bh->b_rdev >> SHIFT)&MAJOR_MASK].
					raid01 + (bh->b_rdev-1) ,
				q, rw, bh) != 1 ) {

			/* request must be split => restore sector and device */
		bh->b_rsector = rsector;
		bh->b_rdev = rdev;
		return -1;

	}

	return 1;
}

static int hptraid01_make_request (request_queue_t *q, int rw, struct buffer_head * bh) {
	/*
	 * Read and Write are totally different cases; split them totally
	 * here
	 */
	if (rw==READA)
		rw = READ;
	
	if (rw==READ)
		return hptraid01_read_request(q,rw,bh);
	else
		return hptraid1_write_request(q,rw,bh);
}

static int read_disk_sb (int major, int minor, unsigned char *buffer,int bufsize)
{
	int ret = -EINVAL;
	struct buffer_head *bh = NULL;
	kdev_t dev = MKDEV(major,minor);
	
	if (blksize_size[major]==NULL)	 /* device doesn't exist */
		return -EINVAL;
	

	/* Superblock is at 4096+412 bytes */
	set_blocksize (dev, 4096);
	bh = bread (dev, 1, 4096);

	
	if (bh) {
		memcpy (buffer, bh->b_data, bufsize);
	} else {
		printk(KERN_ERR "hptraid: Error reading superblock.\n");
		goto abort;
	}
	ret = 0;
abort:
	if (bh)
		brelse (bh);
	return ret;
}

static unsigned long maxsectors (int major,int minor)
{
	unsigned long lba = 0;
	kdev_t dev;
	ide_drive_t *ideinfo;
	
	dev = MKDEV(major,minor);
	ideinfo = ide_info_ptr (dev, 0);
	if (ideinfo==NULL)
		return 0;
	
	
	/* first sector of the last cluster */
	if (ideinfo->head==0) 
		return 0;
	if (ideinfo->sect==0)
		return 0;
	lba = (ideinfo->capacity);

	return lba;
}

static void writeentry(struct hptraid * raid, struct hptraid_dev * disk,
		int index, struct highpoint_raid_conf * prom) {

	int j=0;
	struct gendisk *gd;
	struct block_device *bdev;

	bdev = bdget(MKDEV(disk->major,disk->minor));
	if (bdev && blkdev_get(bdev,FMODE_READ|FMODE_WRITE,0,BDEV_RAW) == 0) {
		raid->disk[index].bdev = bdev;
        	/*
		 * This is supposed to prevent others from stealing our
		 * underlying disks now blank the /proc/partitions table for 
		 * the wrong partition table, so that scripts don't
		 * accidentally mount it and crash the kernel
		 */
		 /* XXX: the 0 is an utter hack  --hch */
		gd=get_gendisk(MKDEV(disk->major, 0));
		if (gd!=NULL) {
 			if (gd->major==disk->major)
 				for (j=1+(disk->minor<<gd->minor_shift);
					j<((disk->minor+1)<<gd->minor_shift);
					j++) gd->part[j].nr_sects=0;					
		}
        }
	raid->disk[index].device = MKDEV(disk->major,disk->minor);
	raid->disk[index].sectors = maxsectors(disk->major,disk->minor);
	raid->stride = (1<<prom->raid0_shift);
	raid->disks = prom->raid_disks;
	raid->sectors = prom->total_secs;
	raid->sectors += raid->sectors&1?1:0;
	raid->magic_0=prom->magic_0;
	raid->magic_1=prom->magic_1;

}

static int probedisk(struct hptraid_dev *disk, int device, u_int8_t type)
{
	int i, j;
        struct highpoint_raid_conf *prom;
	static unsigned char block[4096];
	
 	if (disk->device != -1)	/* disk is occupied? */
 		return 0;
 
 	if (maxsectors(disk->major,disk->minor)==0)
		return 0;
	
        if (read_disk_sb(disk->major,disk->minor,(unsigned char*)&block,sizeof(block)))
        	return 0;
                                                                                                                 
        prom = (struct highpoint_raid_conf*)&block[512];
                
        if (prom->magic!=  0x5a7816f0)
        	return 0;
        switch (prom->type) {
		case HPT_T_SPAN:
		case HPT_T_RAID_0:
		case HPT_T_RAID_1:
		case HPT_T_RAID_01_RAID_0:
			if(prom->type != type)
				return 0;
			break;
		default:
			printk(KERN_INFO "hptraid: unknown raid level-id %i\n",
					prom->type);
			return 0;
        }

 		/* disk from another array? */
	if (raid[device].disks) {	/* only check if raid is not empty */
		if (type == HPT_T_RAID_01_RAID_0 ) {
			if( prom->magic_1 != raid[device].magic_1) {
				return 0;
			}
		}
		else if (prom->magic_0 != raid[device].magic_0) {
				return 0;
		}
	}

	i = prom->disk_number;
	if (i<0)
		return 0;
	if (i>8) 
		return 0;

	if ( type == HPT_T_RAID_01_RAID_0 ) {

			/* allocate helper raid devices for level 0+1 */
		if (raid[device].raid01 == NULL ) {

			raid[device].raid01=
				kmalloc(2 * sizeof(struct hptraid),GFP_KERNEL);
			if ( raid[device].raid01 == NULL ) {
				printk(KERN_ERR "hptraid: out of memory\n");
				raid[device].disks=-1;
				return -ENOMEM;
			}
			memset(raid[device].raid01, 0,
					2 * sizeof(struct hptraid));
		}

			/* find free sub-stucture */
		for (j=0; j<2; j++) {
			if ( raid[device].raid01[j].disks == 0 ||
			     raid[device].raid01[j].magic_0 == prom->magic_0 )
			{
				writeentry(raid[device].raid01+j, disk,
						i, prom);
				break;
			}
		}

			/* no free slot */
		if(j == 2)
			return 0;

		raid[device].stride=raid[device].raid01[j].stride;
		raid[device].disks=j+1;
		raid[device].sectors=raid[device].raid01[j].sectors;
		raid[device].disk[j].sectors=raid[device].raid01[j].sectors;
		raid[device].magic_1=prom->magic_1;
	}
	else {
		writeentry(raid+device, disk, i, prom);
	}

	disk->device=device;
			
	return 1;
}

static void fill_cutoff(struct hptraid * device)
{
	int i,j;
	unsigned long smallest;
	unsigned long bar;
	int count;
	
	bar = 0;
	for (i=0;i<8;i++) {
		smallest = ~0;
		for (j=0;j<8;j++) 
			if ((device->disk[j].sectors < smallest) && (device->disk[j].sectors>bar))
				smallest = device->disk[j].sectors;
		count = 0;
		for (j=0;j<8;j++) 
			if (device->disk[j].sectors >= smallest)
				count++;
		
		smallest = smallest * count;		
		bar = smallest;
		device->cutoff[i] = smallest;
		device->cutoff_disks[i] = count;
		
	}
}

static int count_disks(struct hptraid * raid) {
	int i, count=0;
	for (i=0;i<8;i++) {
		if (raid->disk[i].device!=0) {
			printk(KERN_INFO "Drive %i is %li Mb \n",
				i,raid->disk[i].sectors/2048);
			count++;
		}
	}
	return count;
}

static void raid1_fixup(struct hptraid * raid) {
	int i, count=0;
	for (i=0;i<8;i++) {
			/* disknumbers and total disks values are bogus */
		if (raid->disk[i].device!=0) {
			raid->disk[count]=raid->disk[i];
			if(i > count) {
				memset(raid->disk+i, 0, sizeof(struct hptdisk));
			}
			count++;
		}
	}
	raid->disks=count;
}

static int hptraid_init_one(int device, u_int8_t type, const char * label)
{
	int i,count;
	memset(raid+device, 0, sizeof(struct hptraid));
	for (i=0; i < 14; i++) {
		if( probedisk(devlist+i, device, type) < 0 )
			return -EINVAL;
	}

	/* Initialize raid levels */
	switch (type) {
		case HPT_T_RAID_0:
			fill_cutoff(raid+device);
			break;

		case HPT_T_RAID_1:
			raid1_fixup(raid+device);
			break;

		case HPT_T_RAID_01_RAID_0:
			for(i=0; i < 2 && raid[device].raid01 && 
					raid[device].raid01[i].disks; i++) {
				fill_cutoff(raid[device].raid01+i);
					/* initialize raid 0+1 volumes */
				raid[device].disk[i].device=i+1;
			}
			break;
	}

	/* Verify that we have all disks */

	count=count_disks(raid+device);
		
	if (count != raid[device].disks) {
		printk(KERN_INFO "%s consists of %i drives but found %i drives\n",
				label, raid[device].disks, count);
		return -ENODEV;
	}
	else if (count) {
		printk(KERN_INFO "%s consists of %i drives.\n",
				label, count);
		if (type == HPT_T_RAID_01_RAID_0 ) {
			for(i=0;i<raid[device].disks;i++) {
				count=count_disks(raid[device].raid01+i);
				if(count == raid[device].raid01[i].disks) {
					printk(KERN_ERR "Sub-Raid %i array consists of %i drives.\n",
							i, count);
				}
				else {
					printk(KERN_ERR "Sub-Raid %i array consists of %i drives but found %i disk members.\n",
							i, raid[device].raid01[i].disks,
							count);
					return -ENODEV;
				}
			}
			printk(KERN_WARNING "ataraid%i: raid-0+1 disk failover is not implemented!\n",
					device);
		}
		else if (type == HPT_T_RAID_1) {
			printk(KERN_WARNING "ataraid%i: raid-1 disk failover is not implemented!\n",
					device);
		}	
		/* Initialize the gendisk structure */
	
		ataraid_register_disk(device,raid[device].sectors);

		return 0;
	}
	
	return -ENODEV; /* No more raid volumes */
}

static int hptraid_init(void)
{
 	int retval=-ENODEV;
	int device,i,count=0;
  	
	printk(KERN_INFO "Highpoint HPT370 Softwareraid driver for linux version 0.03\n");

	for(i=0; oplist[i].op; i++) {
		do
		{
			device=ataraid_get_device(oplist[i].op);
			if (device<0)
				return (count?0:-ENODEV);
			retval = hptraid_init_one(device, oplist[i].type,
					oplist[i].label);
			if (retval)
				ataraid_release_device(device);
			else
				count++;
		} while(!retval);
	}
 	return (count?0:retval);
}

static void __exit hptraid_exit (void)
{
	int i,device;
	for (device = 0; device<14; device++) {
		for (i=0;i<8;i++)  {
			struct block_device *bdev = raid[device].disk[i].bdev;
			raid[device].disk[i].bdev = NULL;
			if (bdev)
				blkdev_put(bdev, BDEV_RAW);
		}       
		if (raid[device].sectors) {
			ataraid_release_device(device);
			if( raid[device].raid01 ) {
				kfree(raid[device].raid01);
			}
		}
	}
}

static int hptraid_open(struct inode * inode, struct file * filp) 
{
	MOD_INC_USE_COUNT;
	return 0;
}
static int hptraid_release(struct inode * inode, struct file * filp)
{	
	MOD_DEC_USE_COUNT;
	return 0;
}

module_init(hptraid_init);
module_exit(hptraid_exit);
MODULE_LICENSE("GPL");