Messages in this thread | | | Subject | Re: [PATCH] bcache: add REQ_FUA to avoid data lost in writeback mode | From | Coly Li <> | Date | Mon, 2 Dec 2019 19:08:59 +0800 |
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On 2019/12/2 6:24 下午, kungf wrote: > data may lost when in the follow scene of writeback mode: > 1. client write data1 to bcache > 2. client fdatasync > 3. bcache flush cache set and backing device > if now data1 was not writed back to backing, it was only guaranteed safe in cache. > 4.then cache writeback data1 to backing with only REQ_OP_WRITE > So data1 was not guaranteed in non-volatile storage, it may lost if power interruption >
Hi,
Do you encounter such problem in real work load ? With bcache journal, I don't see the possibility of data lost with your description.
Correct me if I am wrong.
Coly Li
> Signed-off-by: kungf <wings.wyang@gmail.com> > --- > drivers/md/bcache/writeback.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/md/bcache/writeback.c b/drivers/md/bcache/writeback.c > index 4a40f9eadeaf..e5cecb60569e 100644 > --- a/drivers/md/bcache/writeback.c > +++ b/drivers/md/bcache/writeback.c > @@ -357,7 +357,7 @@ static void write_dirty(struct closure *cl) > */ > if (KEY_DIRTY(&w->key)) { > dirty_init(w); > - bio_set_op_attrs(&io->bio, REQ_OP_WRITE, 0); > + bio_set_op_attrs(&io->bio, REQ_OP_WRITE | REQ_FUA, 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; >
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