Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, David Teigland <teigland@redhat.com>,
        Mike Snitzer <snitzer@redhat.com>
Subject: [PATCH 4.14 11/72] dm cache metadata: verify cache has blocks in blocks_are_clean_separate_dirty()
Date:   Thu, 20 Dec 2018 10:18:10 +0100
Message-Id: <20181220085922.779791469@linuxfoundation.org>
In-Reply-To: <20181220085922.332225035@linuxfoundation.org>
References: <20181220085922.332225035@linuxfoundation.org>
User-Agent: quilt/0.65
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

4.14-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Mike Snitzer <snitzer@redhat.com>

commit 687cf4412a343a63928a5c9d91bdc0f522939d43 upstream.

Otherwise dm_bitset_cursor_begin() return -ENODATA.  Other calls to
dm_bitset_cursor_begin() have similar negative checks.

Fixes inability to create a cache in passthrough mode (even though doing
so makes no sense).

Fixes: 0d963b6e65 ("dm cache metadata: fix metadata2 format's blocks_are_clean_separate_dirty")
Cc: stable@vger.kernel.org
Reported-by: David Teigland <teigland@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/md/dm-cache-metadata.c |    4 ++++
 1 file changed, 4 insertions(+)

--- a/drivers/md/dm-cache-metadata.c
+++ b/drivers/md/dm-cache-metadata.c
@@ -929,6 +929,10 @@ static int blocks_are_clean_separate_dir
 	bool dirty_flag;
 	*result = true;
 
+	if (from_cblock(cmd->cache_blocks) == 0)
+		/* Nothing to do */
+		return 0;
+
 	r = dm_bitset_cursor_begin(&cmd->dirty_info, cmd->dirty_root,
 				   from_cblock(cmd->cache_blocks), &cmd->dirty_cursor);
 	if (r) {