md: fix bitmap-on-external-file bug.

commit a2ed9615e3222645007fc19991aedf30eed3ecfd
fixed a bug with 'internal' bitmaps, but in the process broke
'in a file' bitmaps.  So they are broken in 2.6.28

This fixes it, and needs to go in 2.6.28-stable.

Signed-off-by: NeilBrown <neilb@suse.de>
Cc: stable@kernel.org

1 files changed, 5 insertions, 3 deletions

diff --git a/drivers/md/bitmap.c b/drivers/md/bitmap.c
index ab7c8e4a61f9..666b7ba47ec5 100644
--- a/drivers/md/bitmap.c
+++ b/drivers/md/bitmap.c
@@ -964,9 +964,11 @@ static int bitmap_init_from_disk(struct bitmap *bitmap, sector_t start)
                                  */
                                 page = bitmap->sb_page;
                                 offset = sizeof(bitmap_super_t);
-                                read_sb_page(bitmap->mddev, bitmap->offset,
-                                             page,
-                                             index, count);
+                                if (!file)
+                                        read_sb_page(bitmap->mddev,
+                                                     bitmap->offset,
+                                                     page,
+                                                     index, count);
                         } else if (file) {
                                 page = read_page(file, index, bitmap, count);
                                 offset = 0;