• Christoph Hellwig's avatar
    block: add a bi_error field to struct bio · 4246a0b6
    Christoph Hellwig authored
    Currently we have two different ways to signal an I/O error on a BIO:
     (1) by clearing the BIO_UPTODATE flag
     (2) by returning a Linux errno value to the bi_end_io callback
    The first one has the drawback of only communicating a single possible
    error (-EIO), and the second one has the drawback of not beeing persistent
    when bios are queued up, and are not passed along from child to parent
    bio in the ever more popular chaining scenario.  Having both mechanisms
    available has the additional drawback of utterly confusing driver authors
    and introducing bugs where various I/O submitters only deal with one of
    them, and the others have to add boilerplate code to deal with both kinds
    of error returns.
    So add a new bi_error field to store an errno value directly in struct
    bio and remove the existing mechanisms to clean all this up.
    Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
    Reviewed-by: default avatarHannes Reinecke <hare@suse.de>
    Reviewed-by: default avatarNeilBrown <neilb@suse.com>
    Signed-off-by: default avatarJens Axboe <axboe@fb.com>
dm-thin.c 109 KB