medley.c

linux-2.4.29操作系统的源码

		    rsect % r->chunk_size;
	}

	dprintk("medley_make_request :-), disk=%d, rsect=%ul\n", disk,
		rsect);
	bh->b_rdev = r->members[disk];
	bh->b_rsector = rsect;
	return 1;
}

/*
 * Find out which array a drive belongs to, and add it to that array.
 * If it is not a member of a detected array, add a new array for it.
 */
void medley_add_raiddrive(kdev_t dev, struct medley_metadata *md)
{
	int c;

	dprintk("Candidate drive %02x:%02x - drive %d of %d, stride %d, "
		"sectors %ul (%d MB)\n",
		MAJOR(dev), MINOR(dev), md->drive_number,
		md->drives_per_striped_set, md->chunk_size,
		md->total_sectors_low,
		md->total_sectors_low / 1024 / 1024 / 2);

	for (c = 0; c < medley_arrays; c++) {
		if ((raid[c].timestamp[0] == md->creation_timestamp[0]) &&
		    (raid[c].timestamp[1] == md->creation_timestamp[1]) &&
		    (raid[c].timestamp[2] == md->creation_timestamp[2]) &&
		    (raid[c].drives == md->drives_per_striped_set) &&
		    (raid[c].chunk_size == md->chunk_size) &&
		    ((raid[c].present & (1 << md->drive_number)) == 0)) {
			dprintk("Existing array %d\n", c);
			raid[c].present |= (1 << md->drive_number);
			raid[c].members[md->drive_number] = dev;
			break;
		}
	}
	if (c == medley_arrays) {
		dprintk("New array %d\n", medley_arrays);
		if (medley_arrays == MAX_MEDLEY_ARRAYS) {
			printk(KERN_ERR "Medley RAID: "
			       "Too many RAID sets detected - you can change "
			       "the max in the driver.\n");
		} else {
			raid[c].timestamp[0] = md->creation_timestamp[0];
			raid[c].timestamp[1] = md->creation_timestamp[1];
			raid[c].timestamp[2] = md->creation_timestamp[2];
			raid[c].drives = md->drives_per_striped_set;
			raid[c].chunk_size = md->chunk_size;
			raid[c].sectors_per_row = md->chunk_size *
			    md->drives_per_striped_set;

			/* Speedup if chunk size is a power of 2 */
			if (((raid[c].chunk_size - 1) &
			     (raid[c].chunk_size)) == 0) {
				raid[c].chunk_size_log =
				    ffs(raid[c].chunk_size) - 1;
			} else {
				raid[c].chunk_size_log = 0;
			}
			raid[c].present = (1 << md->drive_number);
			raid[c].members[md->drive_number] = dev;
			if (md->major_ver == 1) {
				raid[c].sectors = ((u32 *) (md))[27];
			} else {
				raid[c].sectors = md->total_sectors_low;
			}
			medley_arrays++;
		}
	}
}

/*
 * Read the Medley metadata from a drive.
 * Returns the bh if it was found, otherwise NULL.
 */
struct buffer_head *medley_get_metadata(kdev_t dev)
{
	struct buffer_head *bh = NULL;
	struct pci_dev *pcidev;
	u32 lba;
	int pos;
	struct medley_metadata *md;

	ide_drive_t *drvinfo = ide_info_ptr(dev, 0);
	if ((drvinfo == NULL) || drvinfo->capacity < 1) {
		return NULL;
	}

	dprintk("Probing %02x:%02x\n", MAJOR(dev), MINOR(dev));

	/* If this drive is not on a PCI controller, it is not Medley RAID.
	 * Medley matches the PCI device ID with the metadata to check if
	 * it is valid. Unfortunately it is the only reliable way to identify
	 * the superblock */
	pcidev = drvinfo->hwif ? drvinfo->hwif->pci_dev : NULL;
	if (!pcidev) {
		return NULL;
	}

	/*
	 * 4 copies of the metadata exist, in the following 4 sectors:
	 * last, last-0x200, last-0x400, last-0x600.
	 *
	 * We must try each of these in order, until we find the metadata.
	 * FIXME: This does not take into account drives with 48/64-bit LBA
	 * addressing, even though the Medley RAID version 2 supports these.
	 */
	lba = drvinfo->capacity - 1;
	for (pos = 0; pos < 4; pos++, lba -= 0x200) {
		bh = bread(dev, lba, 512);
		if (!bh) {
			printk(KERN_ERR "Medley RAID (%02x:%02x): "
			       "Error reading metadata (lba=%d)\n",
			       MAJOR(dev), MINOR(dev), lba);
			break;
		}

		/* A valid Medley RAID has the PCI vendor/device ID of its
		 * IDE controller, and the correct checksum. */
		md = (void *) (bh->b_data);

		if (pcidev->vendor == md->vendor_id &&
		    pcidev->device == md->product_id) {
			u16 checksum = 0;
			u16 *p = (void *) (bh->b_data);
			int c;
			for (c = 0; c < 160; c++) {
				checksum += *p++;
			}
			dprintk
			    ("Probing %02x:%02x csum=%d, major_ver=%d\n",
			     MAJOR(dev), MINOR(dev), checksum,
			     md->major_ver);
			if (((checksum == 0xffff) && (md->major_ver == 1))
			    || (checksum == 0)) {
				dprintk("Probing %02x:%02x VALID\n",
					MAJOR(dev), MINOR(dev));
				break;
			}
		}
		/* Was not a valid superblock */
		if (bh) {
			brelse(bh);
			bh = NULL;
		}
	}
	return bh;
}

/*
 * Determine if this drive belongs to a Medley array.
 */
static void medley_probe_drive(int major, int minor)
{
	struct buffer_head *bh;
	kdev_t dev = MKDEV(major, minor);
	struct medley_metadata *md;

	bh = medley_get_metadata(dev);
	if (!bh)
		return;

	md = (void *) (bh->b_data);

	if (md->raid_type != 0x0) {
		printk(KERN_INFO "Medley RAID (%02x:%02x): "
		       "Sorry, this driver currently only supports "
		       "striped sets (RAID level 0).\n", major, minor);
	} else if (md->major_ver == 2 && md->total_sectors_high != 0) {
		printk(KERN_ERR "Medley RAID (%02x:%02x):"
		       "Sorry, the driver only supports 32 bit LBA disks "
		       "(disk too big).\n", major, minor);
	} else if (md->major_ver > 0 && md->major_ver > 2) {
		printk(KERN_INFO "Medley RAID (%02x:%02x): "
		       "Unsupported version (%d.%d) - this driver supports "
		       "Medley version 1.x and 2.x\n",
		       major, minor, md->major_ver, md->minor_ver);
	} else if (md->drives_per_striped_set > MAX_DRIVES_PER_SET) {
		printk(KERN_ERR "Medley RAID (%02x:%02x): "
		       "Striped set too large (%d drives) - please report "
		       "this (and change max in driver).\n",
		       major, minor, md->drives_per_striped_set);
	} else if ((md->drive_number > md->drives_per_striped_set) ||
		   (md->drives_per_striped_set < 1) ||
		   (md->chunk_size < 1)) {
		printk(KERN_ERR "Medley RAID (%02x:%02x): "
		       "Metadata appears to be corrupt.\n", major, minor);
	} else {
		/* We have a good candidate, put it in the correct array */
		medley_add_raiddrive(dev, md);
	}

	if (bh) {
		brelse(bh);
	}
}


/*
 * Taken from hptraid.c, this is called to prevent the device
 * from disappearing from under us and also nullifies the (incorrect)
 * partitions of the underlying disk.
 */
struct block_device *get_device_lock(kdev_t member)
{
	struct block_device *bdev = bdget(member);
	struct gendisk *gd;
	int minor = MINOR(member);
	int j;

	if (bdev
	    && blkdev_get(bdev, FMODE_READ | FMODE_WRITE, 0,
			  BDEV_RAW) == 0) {
		/*
		 * 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(MAJOR(member), 0));
		if (gd != NULL) {
			if (gd->major == MAJOR(member)) {
				for (j = 1 + (minor << gd->minor_shift);
				     j < ((minor + 1) << gd->minor_shift);
				     j++)
					gd->part[j].nr_sects = 0;
			}
		}
	}
	return bdev;
}

/*
 * Initialise the driver.
 */
static __init int medley_init(void)
{
	int c, d;

	memset(raid, 0, MAX_MEDLEY_ARRAYS * sizeof(struct medley_array));

	/* Probe each of the drives on our list */
	for (c = 0; probelist[c] != MKDEV(0, 0); c++) {
		medley_probe_drive(MAJOR(probelist[c]),
				   MINOR(probelist[c]));
	}

	/* Check if the detected sets are complete */
	for (c = 0; c < medley_arrays; c++) {
		if (raid[c].present != (1 << raid[c].drives) - 1) {
			printk(KERN_ERR "Medley RAID: "
			       "Incomplete RAID set deleted - disks:");
			for (d = 0; c < raid[c].drives; c++) {
				if (raid[c].present & (1 << d)) {
					printk(" %02x:%02x",
					       MAJOR(raid[c].members[d]),
					       MINOR(raid[c].members[d]));
				}
			}
			printk("\n");
			if (c + 1 < medley_arrays) {
				memmove(raid + c + 1, raid + c,
					(medley_arrays - c -
					 1) * sizeof(struct medley_array));
			}
			medley_arrays--;
		}
	}

	/* Register any remaining array(s) */
	for (c = 0; c < medley_arrays; c++) {
		int device = ataraid_get_device(&medley_ops);
		if (device < 0) {
			printk(KERN_ERR "Medley RAID: "
			       "Could not get ATARAID device.\n");
			break;
		}
		if (c == 0) {
			/* First array, compute offset to our device ID's */
			medley_devid_offset = device;
			dprintk("Medley_devid_offset: %d\n",
				medley_devid_offset);
		} else if (device - medley_devid_offset != c) {
			printk(KERN_ERR "Medley RAID: "
			       "ATARAID gave us an illegal device ID.\n");
			ataraid_release_device(device);
			break;
		}

		printk(KERN_INFO "Medley RAID: "
		       "Striped set %d consists of %d disks, total %dMiB "
		       "- disks:",
		       c, raid[c].drives,
		       raid[c].sectors / 1024 / 1024 / 2);
		for (d = 0; d < raid[c].drives; d++) {
			printk(" %02x:%02x", MAJOR(raid[c].members[d]),
			       MINOR(raid[c].members[d]));
			raid[c].bdev[d] = get_device_lock(raid[c].members[d]);
		}
		printk("\n");
		raid[c].registered = 1;
		atomic_set(&(raid[c].valid), 1);
		ataraid_register_disk(c, raid[c].sectors);
	}

	if (medley_arrays > 0) {
		printk(KERN_INFO "Medley RAID: %d active RAID set%s\n",
		       medley_arrays, medley_arrays == 1 ? "" : "s");
		return 0;
	}

	printk(KERN_INFO "Medley RAID: No usable RAID sets found\n");
	return -ENODEV;
}

/*
 * Remove the arrays and clean up.
 */
static void __exit medley_exit(void)
{
	int device, d;
	for (device = 0; device < medley_arrays; device++) {
		for (d = 0; d < raid[device].drives; d++) {
			if (raid[device].bdev[d]) {
				blkdev_put(raid[device].bdev[d], BDEV_RAW);
				raid[device].bdev[d] = NULL;
			}
		}
		if (raid[device].registered) {
			ataraid_release_device(device +
					       medley_devid_offset);
			raid[device].registered = 0;
		}
	}
}

/*
 * Called to open the virtual device
 */
static int medley_open(struct inode *inode, struct file *filp)
{
	int device = ((inode->i_rdev >> SHIFT) & MAJOR_MASK) -
	    medley_devid_offset;
	dprintk("medley_open\n");

	if (device < medley_arrays) {
		while (!atomic_read(&(raid[device].valid)))
			sleep_on(&medley_wait_open);
		raid[device].access++;
		MOD_INC_USE_COUNT;
		return (0);
	}
	return -ENODEV;
}

/*
 * Called to release the handle on the virtual device
 */
static int medley_release(struct inode *inode, struct file *filp)
{
	int device = ((inode->i_rdev >> SHIFT) & MAJOR_MASK) -
	    medley_devid_offset;
	dprintk("medley_release\n");
	raid[device].access--;
	MOD_DEC_USE_COUNT;
	return 0;
}

module_init(medley_init);
module_exit(medley_exit);
MODULE_LICENSE("GPL");