linux-kernel - [PATCH 5.15 026/135] dm mirror log: clear log bits up to BITS_PER

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Date:   Mon, 27 Jun 2022 13:20:33 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Benjamin Marzinski <bmarzins@...hat.com>,
        Mikulas Patocka <mpatocka@...hat.com>,
        Mike Snitzer <snitzer@...nel.org>
Subject: [PATCH 5.15 026/135] dm mirror log: clear log bits up to BITS_PER_LONG boundary

From: Mikulas Patocka <mpatocka@...hat.com>

commit 90736eb3232d208ee048493f371075e4272e0944 upstream.

Commit 85e123c27d5c ("dm mirror log: round up region bitmap size to
BITS_PER_LONG") introduced a regression on 64-bit architectures in the
lvm testsuite tests: lvcreate-mirror, mirror-names and vgsplit-operation.

If the device is shrunk, we need to clear log bits beyond the end of the
device. The code clears bits up to a 32-bit boundary and then calculates
lc->sync_count by summing set bits up to a 64-bit boundary (the commit
changed that; previously, this boundary was 32-bit too). So, it was using
some non-zeroed bits in the calculation and this caused misbehavior.

Fix this regression by clearing bits up to BITS_PER_LONG boundary.

Fixes: 85e123c27d5c ("dm mirror log: round up region bitmap size to BITS_PER_LONG")
Cc: stable@...r.kernel.org
Reported-by: Benjamin Marzinski <bmarzins@...hat.com>
Signed-off-by: Mikulas Patocka <mpatocka@...hat.com>
Signed-off-by: Mike Snitzer <snitzer@...nel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
 drivers/md/dm-log.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/md/dm-log.c
+++ b/drivers/md/dm-log.c
@@ -615,7 +615,7 @@ static int disk_resume(struct dm_dirty_l
 			log_clear_bit(lc, lc->clean_bits, i);

 	/* clear any old bits -- device has shrunk */
-	for (i = lc->region_count; i % (sizeof(*lc->clean_bits) << BYTE_SHIFT); i++)
+	for (i = lc->region_count; i % BITS_PER_LONG; i++)
 		log_clear_bit(lc, lc->clean_bits, i);

 	/* copy clean across to sync */