On 2017/9/27 下午4:28, Michael Lyle wrote:
> SET_KEY_DIRTY sets it to false when bi_status is not 0.
>
> We do the write if KEY_DIRTY is true, else it is skipped.
I see your point, yes you are right.
Reviewed-by: Coly Li <colyli@xxxxxxx>
Thanks!
> On Wed, Sep 27, 2017 at 1:22 AM, Coly Li <i@xxxxxxx> wrote:
>> 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
--
Coly Li
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