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From:   Hans Holmberg <hans.ml.holmberg@owltronix.com>
To:     Matias Bjorling <mb@lightnvm.io>
Cc:     Javier Gonzales <javier@cnexlabs.com>, linux-block@vger.kernel.org,
        linux-kernel@vger.kernel.org,
        Hans Holmberg <hans.holmberg@cnexlabs.com>
Subject: [PATCH v2 1/7] lightnvm: pblk: fix resubmission of overwritten write err lbas
Date:   Mon,  5 Nov 2018 13:26:04 +0100
Message-Id: <20181105122610.1555-2-hans.ml.holmberg@owltronix.com>
In-Reply-To: <20181105122610.1555-1-hans.ml.holmberg@owltronix.com>
References: <20181105122610.1555-1-hans.ml.holmberg@owltronix.com>
Sender: linux-kernel-owner@vger.kernel.org
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From: Hans Holmberg <hans.holmberg@cnexlabs.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@cnexlabs.com>
---
 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