md: support bitmap offset appropriate for external-metadata arrays.
For md arrays were metadata is managed externally, the kernel does not
know about a superblock so the superblock offset is 0.
If we want to have a write-intent-bitmap near the end of the
devices of such an array, we should support sector_t sized offset.
We need offset be possibly negative for when the bitmap is before
the metadata, so use loff_t instead.
Also add sanity check that bitmap does not overlap with data.
Signed-off-by: NeilBrown <neilb@suse.de>
diff --git a/drivers/md/bitmap.c b/drivers/md/bitmap.c
index b1bcd36..9588654 100644
--- a/drivers/md/bitmap.c
+++ b/drivers/md/bitmap.c
@@ -212,7 +212,7 @@
*/
/* IO operations when bitmap is stored near all superblocks */
-static struct page *read_sb_page(mddev_t *mddev, long offset,
+static struct page *read_sb_page(mddev_t *mddev, loff_t offset,
struct page *page,
unsigned long index, int size)
{
@@ -287,14 +287,22 @@
while ((rdev = next_active_rdev(rdev, mddev)) != NULL) {
int size = PAGE_SIZE;
- long offset = mddev->bitmap_info.offset;
+ loff_t offset = mddev->bitmap_info.offset;
if (page->index == bitmap->file_pages-1)
size = roundup(bitmap->last_page_size,
bdev_logical_block_size(rdev->bdev));
/* Just make sure we aren't corrupting data or
* metadata
*/
- if (offset < 0) {
+ if (mddev->external) {
+ /* Bitmap could be anywhere. */
+ if (rdev->sb_start + offset + (page->index *(PAGE_SIZE/512)) >
+ rdev->data_offset &&
+ rdev->sb_start + offset <
+ rdev->data_offset + mddev->dev_sectors +
+ (PAGE_SIZE/512))
+ goto bad_alignment;
+ } else if (offset < 0) {
/* DATA BITMAP METADATA */
if (offset
+ (long)(page->index * (PAGE_SIZE/512))