[Btrfs-devel] Bugs in extent_io.c:submit_extent_page()

[Peter Teoh]

This function not really completely written yet, I supposed.   But I
don't really know how to fix it either.

In extent_io.c:

static int submit_extent_page(int rw, struct extent_io_tree *tree,
                              struct page *page, sector_t sector,
                              size_t size, unsigned long offset,
                              struct block_device *bdev,
                              struct bio **bio_ret,
                              unsigned long max_pages,
                              bio_end_io_t end_io_func)
{
        int ret = 0;
        struct bio *bio;
        int nr;

        if (bio_ret && *bio_ret) {
                bio = *bio_ret;
                if (bio->bi_sector + (bio->bi_size >> 9) != sector ||
                    bio_add_page(bio, page, size, offset) < size) {
                        ret = submit_one_bio(rw, bio);
                        bio = NULL;
                } else {
                        return 0;===>>>error condition.
                }
        }
        nr = bio_get_nr_vecs(bdev);
        bio = extent_bio_alloc(bdev, sector, nr, GFP_NOFS | __GFP_HIGH);
        if (!bio) {
                printk("failed to allocate bio nr %d\n", nr); ====>
what to do after this????? should we just return 0 just like above????
        }


        bio_add_page(bio, page, size, offset);==>bio_add_page() will
immediate DEREFERENCE the bio ptr, and so it will lead to crashes.
        bio->bi_end_io = end_io_func;
        bio->bi_private = tree;

????

-- 
Regards,
Peter Teoh