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md: fix max sectors calculation for super 1.0

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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: Xiao Ni <xni@redhat.com>
Signed-off-by: Song Liu <songliubraving@fb.com>
This commit is contained in:
Xiao Ni 2020-06-30 15:55:36 +08:00 committed by Song Liu
parent a9e8e18aaf
commit d9c0fa509e
1 changed files with 31 additions and 4 deletions
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35
drivers/md/md.c
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@ -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);