On 17.03.2019 20:24, Matias Bjørling wrote:
On 3/16/19 3:43 PM, Javier González wrote:
On 14 Mar 2019, at 09.04, Igor Konopko <igor.j.konopko@xxxxxxxxx> wrote:
In case of OOB recovery, when some of the chunks are in closed state,
we are calculating number of written sectors in line incorrectly,
because we are always counting chunk WP, which for closed chunks
does not longer reflects written sectors in particular chunks. This
patch for such a chunks takes clba field instead.
Signed-off-by: Igor Konopko <igor.j.konopko@xxxxxxxxx>
---
drivers/lightnvm/pblk-recovery.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)
diff --git a/drivers/lightnvm/pblk-recovery.c
b/drivers/lightnvm/pblk-recovery.c
index 83b467b..bcd3633 100644
--- a/drivers/lightnvm/pblk-recovery.c
+++ b/drivers/lightnvm/pblk-recovery.c
@@ -101,6 +101,8 @@ static void pblk_update_line_wp(struct pblk
*pblk, struct pblk_line *line,
static u64 pblk_sec_in_open_line(struct pblk *pblk, struct pblk_line
*line)
{
+ struct nvm_tgt_dev *dev = pblk->dev;
+ struct nvm_geo *geo = &dev->geo;
struct pblk_line_meta *lm = &pblk->lm;
int nr_bb = bitmap_weight(line->blk_bitmap, lm->blk_per_line);
u64 written_secs = 0;
@@ -113,7 +115,11 @@ static u64 pblk_sec_in_open_line(struct pblk
*pblk, struct pblk_line *line)
if (chunk->state & NVM_CHK_ST_OFFLINE)
continue;
- written_secs += chunk->wp;
+ if (chunk->state & NVM_CHK_ST_OPEN)
+ written_secs += chunk->wp;
+ else if (chunk->state & NVM_CHK_ST_CLOSED)
+ written_secs += geo->clba;
+
valid_chunks++;
}
--
2.9.5
Mmmm. The change is correct, but can you develop on why the WP does not
reflect the written sectors in a closed chunk? As I understand it, the
WP reflects the last written sector; if it happens to be WP == clba, then
the chunk state machine transitions to closed, but the WP remains
untouched. It is only when we reset the chunk that the WP comes back to
0. Am I missing something?
I agree with Javier. In OCSSD, the write pointer shall always be valid.
So based on OCSSD 2.0 spec "If WP = SLBA + NLB, the chunk is closed"
(also on "Figure 5: Chunk State Diagram in spec": WP = SLBA + NLB for
closed chunk), my understanding it that the WP is not valid for that
particular use case, since in written_secs we want to obtain NLB field
(relative within chunk, without starting LBA value). So that's why I
used fixed CLBA here, since it WP pointer for closed chunk is absolute
value instead of relative one.
Did I misunderstood sth in the spec?
