md: don't write more than is required of the last page of a bitmap
It is possible that real data or metadata follows the bitmap without full page
alignment.
So limit the last write to be only the required number of bytes, rounded up to
the hard sector size of the device.
Signed-off-by: Neil Brown <neilb@suse.de>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/drivers/md/bitmap.c b/drivers/md/bitmap.c
index 5a4a74c..9620d45 100644
--- a/drivers/md/bitmap.c
+++ b/drivers/md/bitmap.c
@@ -255,19 +255,25 @@
}
-static int write_sb_page(mddev_t *mddev, long offset, struct page *page, int wait)
+static int write_sb_page(struct bitmap *bitmap, struct page *page, int wait)
{
mdk_rdev_t *rdev;
struct list_head *tmp;
+ mddev_t *mddev = bitmap->mddev;
ITERATE_RDEV(mddev, rdev, tmp)
if (test_bit(In_sync, &rdev->flags)
- && !test_bit(Faulty, &rdev->flags))
+ && !test_bit(Faulty, &rdev->flags)) {
+ int size = PAGE_SIZE;
+ if (page->index == bitmap->file_pages-1)
+ size = roundup(bitmap->last_page_size,
+ bdev_hardsect_size(rdev->bdev));
md_super_write(mddev, rdev,
- (rdev->sb_offset<<1) + offset
+ (rdev->sb_offset<<1) + bitmap->offset
+ page->index * (PAGE_SIZE/512),
- PAGE_SIZE,
+ size,
page);
+ }
if (wait)
md_super_wait(mddev);
@@ -282,7 +288,7 @@
struct buffer_head *bh;
if (bitmap->file == NULL)
- return write_sb_page(bitmap->mddev, bitmap->offset, page, wait);
+ return write_sb_page(bitmap, page, wait);
bh = page_buffers(page);
@@ -923,6 +929,7 @@
}
bitmap->filemap[bitmap->file_pages++] = page;
+ bitmap->last_page_size = count;
}
paddr = kmap_atomic(page, KM_USER0);
if (bitmap->flags & BITMAP_HOSTENDIAN)