md: fix loading of out-of-date bitmap. (b74fd282) · Commits · 戴 / test

When md is loading a bitmap which it knows is out of date, it fills each page with 1s and writes it back out again. However the write_page call makes used of bitmap->file_pages and bitmap->last_page_size which haven't been set correctly yet. So this can sometimes fail. Move the setting of file_pages and last_page_size to before the call to write_page. This bug can cause the assembly on an array to fail, thus making the data inaccessible. Hence I think it is a suitable candidate for -stable. Cc: stable@kernel.org Reported-by:

Vojtech Pavlik <vojtech@suse.cz> Signed-off-by:

NeilBrown <neilb@suse.de>

drivers/md/bitmap.c

+4 −7

Original line number	Diff line number	Diff line
		@@ -986,6 +986,9 @@ static int bitmap_init_from_disk(struct bitmap *bitmap, sector_t start)
		oldindex = index;
		oldpage = page;

		bitmap->filemap[bitmap->file_pages++] = page;
		bitmap->last_page_size = count;

		if (outofdate) {
		/*
		* if bitmap is out of date, dirty the
		@@ -998,16 +1001,10 @@ static int bitmap_init_from_disk(struct bitmap *bitmap, sector_t start)
		write_page(bitmap, page, 1);

		ret = -EIO;
		if (bitmap->flags & BITMAP_WRITE_ERROR) {
		/* release, page not in filemap yet */
		put_page(page);
		if (bitmap->flags & BITMAP_WRITE_ERROR)
		goto err;
		}
		}

		bitmap->filemap[bitmap->file_pages++] = page;
		bitmap->last_page_size = count;
		}
		paddr = kmap_atomic(page, KM_USER0);
		if (bitmap->flags & BITMAP_HOSTENDIAN)
		b = test_bit(bit, paddr);

Admin message