On Tue, Aug 01, 2017 at 11:11:37PM -0700, Song Liu wrote: > When bitmap_resize() is used to initialize the bitmap, it is > necessary to preserve the whole page of sb_page instead of just > the header (bitmap_super_t). This is because the sb_page may > contain bitmap read from the disks (initialized by mdadm). > > Note that, this code path is only triggered with certain > combinations of parameters. One example is when raid456 array > is created with write journal Good catch, this issue probably only exists with journal, because we write superblock there. > Signed-off-by: Song Liu <songliubraving@xxxxxx> > --- > drivers/md/bitmap.c | 3 +-- > 1 file changed, 1 insertion(+), 2 deletions(-) > > diff --git a/drivers/md/bitmap.c b/drivers/md/bitmap.c > index 40f3cd7..93dd809 100644 > --- a/drivers/md/bitmap.c > +++ b/drivers/md/bitmap.c > @@ -2118,7 +2118,7 @@ int bitmap_resize(struct bitmap *bitmap, sector_t blocks, > if (store.sb_page && bitmap->storage.sb_page) > memcpy(page_address(store.sb_page), > page_address(bitmap->storage.sb_page), > - sizeof(bitmap_super_t)); > + init ? PAGE_SIZE : sizeof(bitmap_super_t)); I think this should be 'roundup(sizeof(bitmap_super_t), bdev_logical_block_size(rdev->bdev))', we not always read one page. The init check is unnecessary too, because if it isn't init, we will initialize the bitmaps later in bitmap_resize, so the copy doesn't matter. Thanks, Shaohua > bitmap_file_unmap(&bitmap->storage); > bitmap->storage = store; > > -- > 2.9.3 > -- To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
