Btrfs: finish read pages in the order they are submitted

[mv-sheeva.git] / fs / btrfs / extent_io.c

diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index 7073cbb1b2d4cfc169dfea2ca435d353f282250f..355a973719a02ae1276c842b69e76aeb5965ec46 100644 (file)
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -1750,7 +1750,8 @@ static void end_bio_extent_writepage(struct bio *bio, int err)
 static void end_bio_extent_readpage(struct bio *bio, int err)
 {
        int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
-       struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1;
+       struct bio_vec *bvec_end = bio->bi_io_vec + bio->bi_vcnt - 1;
+       struct bio_vec *bvec = bio->bi_io_vec;
        struct extent_io_tree *tree;
        u64 start;
        u64 end;
@@ -1773,7 +1774,7 @@ static void end_bio_extent_readpage(struct bio *bio, int err)
                else
                        whole_page = 0;
 
-               if (--bvec >= bio->bi_io_vec)
+               if (++bvec <= bvec_end)
                        prefetchw(&bvec->bv_page->flags);
 
                if (uptodate && tree->ops && tree->ops->readpage_end_io_hook) {
@@ -1818,7 +1819,7 @@ static void end_bio_extent_readpage(struct bio *bio, int err)
                        }
                        check_page_locked(tree, page);
                }
-       } while (bvec >= bio->bi_io_vec);
+       } while (bvec <= bvec_end);
 
        bio_put(bio);
 }