JFFS2: don't fail on bitflips in OOB

computersforpeace · David Woodhouse · commit 74d83beaa229 · 2012-09-29T15:34:13.000+01:00
JFFS2 was designed without thought for OOB bitflips, it seems, but they
can occur and will be reported to JFFS2 via mtd_read_oob()[1]. We don't
want to fail on these transactions, since the data was corrected.

[1] Few drivers report bitflips for OOB-only transactions. With such
    drivers, this patch should have no effect.

Signed-off-by: Brian Norris &lt;computersforpeace@gmail.com&gt;
Cc: stable@vger.kernel.org
Signed-off-by: Artem Bityutskiy &lt;artem.bityutskiy@linux.intel.com&gt;
Signed-off-by: David Woodhouse &lt;David.Woodhouse@intel.com&gt;
diff --git a/fs/jffs2/wbuf.c b/fs/jffs2/wbuf.c
@@ -1044,10 +1044,10 @@ int jffs2_check_oob_empty(struct jffs2_sb_info *c,
 	ops.datbuf = NULL;
 
 	ret = mtd_read_oob(c->mtd, jeb->offset, &ops);
-	if (ret || ops.oobretlen != ops.ooblen) {
+	if ((ret && !mtd_is_bitflip(ret)) || ops.oobretlen != ops.ooblen) {
 		pr_err("cannot read OOB for EB at %08x, requested %zd bytes, read %zd bytes, error %d\n",
 		       jeb->offset, ops.ooblen, ops.oobretlen, ret);
-		if (!ret)
+		if (!ret || mtd_is_bitflip(ret))
 			ret = -EIO;
 		return ret;
 	}
@@ -1086,10 +1086,10 @@ int jffs2_check_nand_cleanmarker(struct jffs2_sb_info *c,
 	ops.datbuf = NULL;
 
 	ret = mtd_read_oob(c->mtd, jeb->offset, &ops);
-	if (ret || ops.oobretlen != ops.ooblen) {
+	if ((ret && !mtd_is_bitflip(ret)) || ops.oobretlen != ops.ooblen) {
 		pr_err("cannot read OOB for EB at %08x, requested %zd bytes, read %zd bytes, error %d\n",
 		       jeb->offset, ops.ooblen, ops.oobretlen, ret);
-		if (!ret)
+		if (!ret || mtd_is_bitflip(ret))
 			ret = -EIO;
 		return ret;
 	}
