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@xxxxxxx>
---
drivers/md/bitmap.c | 14 +++++++++++---
drivers/md/md.h | 6 ++++--
2 files changed, 15 insertions(+), 5 deletions(-)
diff --git a/drivers/md/bitmap.c b/drivers/md/bitmap.c
index 4df173a..5b77e5c 100644
--- a/drivers/md/bitmap.c
+++ b/drivers/md/bitmap.c
@@ -212,7 +212,7 @@ static void bitmap_checkfree(struct bitmap *bitmap, unsigned long page)
*/
/* 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 @@ static int write_sb_page(struct bitmap *bitmap, struct page *page, int wait)
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))
diff --git a/drivers/md/md.h b/drivers/md/md.h
index b35b29d..aa67532 100644
--- a/drivers/md/md.h
+++ b/drivers/md/md.h
@@ -282,11 +282,13 @@ struct mddev_s
struct bitmap *bitmap; /* the bitmap for the device */
struct {
struct file *file; /* the bitmap file */
- long offset; /* offset from superblock of
+ loff_t offset; /* offset from superblock of
* start of bitmap. May be
* negative, but not '0'
+ * For external metadata, offset
+ * from start of device.
*/
- long default_offset; /* this is the offset to use when
+ loff_t default_offset; /* this is the offset to use when
* hot-adding a bitmap. It should
* eventually be settable by sysfs.
*/
--
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