On 2017/9/27 上午3:24, Michael Lyle wrote:
> If an IO operation fails, and we didn't successfully read data from the
> cache, don't writeback invalid/partial data to the backing disk.
>
> Signed-off-by: Michael Lyle <mlyle@xxxxxxxx>
> ---
> drivers/md/bcache/writeback.c | 19 +++++++++++++------
> 1 file changed, 13 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/md/bcache/writeback.c b/drivers/md/bcache/writeback.c
> index e663ca082183..eea49bf36401 100644
> --- a/drivers/md/bcache/writeback.c
> +++ b/drivers/md/bcache/writeback.c
> @@ -179,13 +179,20 @@ static void write_dirty(struct closure *cl)
> struct dirty_io *io = container_of(cl, struct dirty_io, cl);
> struct keybuf_key *w = io->bio.bi_private;
>
> - dirty_init(w);
> - bio_set_op_attrs(&io->bio, REQ_OP_WRITE, 0);
> - io->bio.bi_iter.bi_sector = KEY_START(&w->key);
> - bio_set_dev(&io->bio, io->dc->bdev);
> - io->bio.bi_end_io = dirty_endio;
> + /* IO errors are signalled using the dirty bit on the key.
> + * If we failed to read, we should not attempt to write to the
> + * backing device. Instead, immediately go to write_dirty_finish
> + * to clean up.
> + */
> + if (KEY_DIRTY(&w->key)) {
Maybe it should be "if (!KEY_DIRTY(&w->key))" ? In dirty_endio(),
SET_KEY_DIRTY() is called only when bio->bi_status is not 0.
> + dirty_init(w);
> + bio_set_op_attrs(&io->bio, REQ_OP_WRITE, 0);
> + io->bio.bi_iter.bi_sector = KEY_START(&w->key);
> + bio_set_dev(&io->bio, io->dc->bdev);
> + io->bio.bi_end_io = dirty_endio;
>
> - closure_bio_submit(&io->bio, cl);
> + closure_bio_submit(&io->bio, cl);
> + }
>
> continue_at(cl, write_dirty_finish, io->dc->writeback_write_wq);
> }
>
--
Coly Li
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