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Commit b74fd282 authored by NeilBrown's avatar NeilBrown
Browse files

md: fix loading of out-of-date bitmap. 



When md is loading a bitmap which it knows is out of date, it fills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: default avatarVojtech Pavlik <vojtech@suse.cz>
Signed-off-by: default avatarNeilBrown <neilb@suse.de>
parent b4348f32

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				 * if bitmap is out of date, dirty the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);