lkml.org 
[lkml]   [2019]   [Dec]   [2]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH] bcache: add REQ_FUA to avoid data lost in writeback mode
From
Date
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;
>

\
 
 \ /
  Last update: 2019-12-02 12:09    [W:0.083 / U:61.956 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site