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Commit a6ff7e08 authored by Jonathan Brassow's avatar Jonathan Brassow Committed by NeilBrown
Browse files

md: separate meta and data devs 



Allow the metadata to be on a separate device from the
data.

This doesn't mean the data and metadata will by on separate
physical devices - it simply gives device-mapper and userspace
tools more flexibility.

Signed-off-by: default avatarNeilBrown <neilb@suse.de>
parent ccebd4c4

drivers/md/bitmap.c

+5 −1
Original line number Diff line number Diff line
@@ -264,14 +264,18 @@ static mdk_rdev_t *next_active_rdev(mdk_rdev_t *rdev, mddev_t *mddev) 
static int write_sb_page(struct bitmap *bitmap, struct page *page, int wait)

{

	mdk_rdev_t *rdev = NULL;

	struct block_device *bdev;

	mddev_t *mddev = bitmap->mddev;



	while ((rdev = next_active_rdev(rdev, mddev)) != NULL) {

		int size = PAGE_SIZE;

		loff_t offset = mddev->bitmap_info.offset;



		bdev = (rdev->meta_bdev) ? rdev->meta_bdev : rdev->bdev;



		if (page->index == bitmap->file_pages-1)

			size = roundup(bitmap->last_page_size,

				       bdev_logical_block_size(rdev->bdev));

				       bdev_logical_block_size(bdev));

		/* Just make sure we aren't corrupting data or

		 * metadata

		 */

drivers/md/md.c

+6 −4
Original line number Diff line number Diff line
@@ -765,7 +765,7 @@ void md_super_write(mddev_t *mddev, mdk_rdev_t *rdev, 
	 */

	struct bio *bio = bio_alloc_mddev(GFP_NOIO, 1, mddev);



	bio->bi_bdev = rdev->bdev;

	bio->bi_bdev = rdev->meta_bdev ? rdev->meta_bdev : rdev->bdev;

	bio->bi_sector = sector;

	bio_add_page(bio, page, size, 0);

	bio->bi_private = rdev;
@@ -803,7 +803,8 @@ int sync_page_io(mdk_rdev_t *rdev, sector_t sector, int size, 


	rw |= REQ_SYNC | REQ_UNPLUG;



	bio->bi_bdev = rdev->bdev;

	bio->bi_bdev = (metadata_op && rdev->meta_bdev) ?

		rdev->meta_bdev : rdev->bdev;

	if (metadata_op)

		bio->bi_sector = sector + rdev->sb_start;

	else
@@ -4435,7 +4436,9 @@ int md_run(mddev_t *mddev) 
		 * We don't want the data to overlap the metadata,

		 * Internal Bitmap issues have been handled elsewhere.

		 */

		if (rdev->data_offset < rdev->sb_start) {

		if (rdev->meta_bdev) {

			/* Nothing to check */;

		} else if (rdev->data_offset < rdev->sb_start) {

			if (mddev->dev_sectors &&

			    rdev->data_offset + mddev->dev_sectors

			    > rdev->sb_start) {
@@ -5532,7 +5535,6 @@ static int update_size(mddev_t *mddev, sector_t num_sectors) 
	 * sb_start or, if that is <data_offset, it must fit before the size

	 * of each device.  If num_sectors is zero, we find the largest size

	 * that fits.



	 */

	if (mddev->sync_thread)

		return -EBUSY;

drivers/md/md.h

+6 −0
Original line number Diff line number Diff line
@@ -60,6 +60,12 @@ struct mdk_rdev_s 
	mddev_t *mddev;			/* RAID array if running */

	int last_events;		/* IO event timestamp */



	/*

	 * If meta_bdev is non-NULL, it means that a separate device is

	 * being used to store the metadata (superblock/bitmap) which

	 * would otherwise be contained on the same device as the data (bdev).

	 */

	struct block_device *meta_bdev;

	struct block_device *bdev;	/* block device handle */



	struct page	*sb_page;