Re: [PATCH] Btrfs: fix BUG_ON in btrfs_submit_compressed_write

On Wed, Jun 22, 2016 at 06:32:06PM -0700, Liu Bo wrote:

This is similar to btrfs_submit_compressed_read(), if we fail after
bio is allocated, then we can use bio_endio() and errors are saved
 in bio->bi_error.  But please note that we don't return errors to
its caller because the caller assumes it won't call endio to cleanup
on error.

This sounds strange, where do we notice that some of the bios failed?