Commit d9c0fa50 authored by Xiao Ni's avatar Xiao Ni Committed by Song Liu
Browse files

md: fix max sectors calculation for super 1.0 



To grow size of super 1.0 raid array, it is necessary to check the device
max usable size.

Now it uses rdev->sectors for max usable size. If one disk is 500G and the
raid device only uses the 100GB of this disk. rdev->sectors can't tell the
real max usable size. The max usable size should be

dev_size-(superblock_size+bitmap_size+badblock_size).

Also, remove unnecessary sb_start update in super_1_rdev_size_change().

Signed-off-by: default avatarXiao Ni <xni@redhat.com>
Signed-off-by: default avatarSong Liu <songliubraving@fb.com>
parent a9e8e18a

drivers/md/md.c

+31 −4
Original line number Diff line number Diff line
@@ -2193,6 +2193,24 @@ retry: 
	sb->sb_csum = calc_sb_1_csum(sb);

}



static sector_t super_1_choose_bm_space(sector_t dev_size)

{

	sector_t bm_space;



	/* if the device is bigger than 8Gig, save 64k for bitmap

	 * usage, if bigger than 200Gig, save 128k

	 */

	if (dev_size < 64*2)

		bm_space = 0;

	else if (dev_size - 64*2 >= 200*1024*1024*2)

		bm_space = 128*2;

	else if (dev_size - 4*2 > 8*1024*1024*2)

		bm_space = 64*2;

	else

		bm_space = 4*2;

	return bm_space;

}



static unsigned long long

super_1_rdev_size_change(struct md_rdev *rdev, sector_t num_sectors)

{
@@ -2213,13 +2231,22 @@ super_1_rdev_size_change(struct md_rdev *rdev, sector_t num_sectors) 
		return 0;

	} else {

		/* minor version 0; superblock after data */

		sector_t sb_start;

		sb_start = (i_size_read(rdev->bdev->bd_inode) >> 9) - 8*2;

		sector_t sb_start, bm_space;

		sector_t dev_size = i_size_read(rdev->bdev->bd_inode) >> 9;



		/* 8K is for superblock */

		sb_start = dev_size - 8*2;

		sb_start &= ~(sector_t)(4*2 - 1);

		max_sectors = rdev->sectors + sb_start - rdev->sb_start;



		bm_space = super_1_choose_bm_space(dev_size);



		/* Space that can be used to store date needs to decrease

		 * superblock bitmap space and bad block space(4K)

		 */

		max_sectors = sb_start - bm_space - 4*2;



		if (!num_sectors || num_sectors > max_sectors)

			num_sectors = max_sectors;

		rdev->sb_start = sb_start;

	}

	sb = page_address(rdev->sb_page);

	sb->data_size = cpu_to_le64(num_sectors);

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