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md: separate meta and data devs

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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: NeilBrown <neilb@suse.de>
This commit is contained in:
Jonathan Brassow 2011-01-14 09:14:34 +11:00 committed by NeilBrown
parent ccebd4c415
commit a6ff7e089c
3 changed files with 17 additions and 5 deletions
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6
drivers/md/bitmap.c
View File

@ -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
*/

10
drivers/md/md.c
View File

@ -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;

6
drivers/md/md.h
View File

@ -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;