linux-kernel - [GIT PULL 04/21] lightnvm: pblk: fix resubmission of overwritten write err lbas

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Message-Id: <20181211191627.15542-5-mb@lightnvm.io>
Date:   Tue, 11 Dec 2018 20:16:10 +0100
From:   Matias Bjørling <mb@...htnvm.io>
To:     axboe@...com
Cc:     linux-block@...r.kernel.org, linux-kernel@...r.kernel.org,
        Hans Holmberg <hans.holmberg@...xlabs.com>,
        Matias Bjørling <mb@...htnvm.io>
Subject: [GIT PULL 04/21] lightnvm: pblk: fix resubmission of overwritten write err lbas

From: Hans Holmberg <hans.holmberg@...xlabs.com>

Make sure we only look up valid lba addresses on the resubmission path.

If an lba is invalidated in the write buffer, that sector will be
submitted to disk (as it is already mapped to a ppa), and that write
might fail, resulting in a crash when trying to look up the lba in the
mapping table (as the lba is marked as invalid).

Signed-off-by: Hans Holmberg <hans.holmberg@...xlabs.com>
Reviewed-by: Javier González <javier@...igon.com>
Signed-off-by: Matias Bjørling <mb@...htnvm.io>
---
 drivers/lightnvm/pblk-write.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/drivers/lightnvm/pblk-write.c b/drivers/lightnvm/pblk-write.c
index fa8726493b39..3ddd16f47106 100644
--- a/drivers/lightnvm/pblk-write.c
+++ b/drivers/lightnvm/pblk-write.c
@@ -148,9 +148,11 @@ static void pblk_prepare_resubmit(struct pblk *pblk, unsigned int sentry,
 		w_ctx = &entry->w_ctx;
 
 		/* Check if the lba has been overwritten */
-		ppa_l2p = pblk_trans_map_get(pblk, w_ctx->lba);
-		if (!pblk_ppa_comp(ppa_l2p, entry->cacheline))
-			w_ctx->lba = ADDR_EMPTY;
+		if (w_ctx->lba != ADDR_EMPTY) {
+			ppa_l2p = pblk_trans_map_get(pblk, w_ctx->lba);
+			if (!pblk_ppa_comp(ppa_l2p, entry->cacheline))
+				w_ctx->lba = ADDR_EMPTY;
+		}
 
 		/* Mark up the entry as submittable again */
 		flags = READ_ONCE(w_ctx->flags);
-- 
2.17.1