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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Nikos Tsironis <ntsironis@arrikto.com>,
        Ming-Hung Tsai <mtsai@redhat.com>,
        Mike Snitzer <snitzer@redhat.com>
Subject: [PATCH 4.19 234/247] dm era: Verify the data block size hasnt changed
Date:   Mon,  1 Mar 2021 17:14:14 +0100
Message-Id: <20210301161043.157832452@linuxfoundation.org>
In-Reply-To: <20210301161031.684018251@linuxfoundation.org>
References: <20210301161031.684018251@linuxfoundation.org>
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From: Nikos Tsironis <ntsironis@arrikto.com>

commit c8e846ff93d5eaa5384f6f325a1687ac5921aade upstream.

dm-era doesn't support changing the data block size of existing devices,
so check explicitly that the requested block size for a new target
matches the one stored in the metadata.

Fixes: eec40579d84873 ("dm: add era target")
Cc: stable@vger.kernel.org # v3.15+
Signed-off-by: Nikos Tsironis <ntsironis@arrikto.com>
Reviewed-by: Ming-Hung Tsai <mtsai@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/md/dm-era-target.c |   10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

--- a/drivers/md/dm-era-target.c
+++ b/drivers/md/dm-era-target.c
@@ -563,6 +563,15 @@ static int open_metadata(struct era_meta
 	}
 
 	disk = dm_block_data(sblock);
+
+	/* Verify the data block size hasn't changed */
+	if (le32_to_cpu(disk->data_block_size) != md->block_size) {
+		DMERR("changing the data block size (from %u to %llu) is not supported",
+		      le32_to_cpu(disk->data_block_size), md->block_size);
+		r = -EINVAL;
+		goto bad;
+	}
+
 	r = dm_tm_open_with_sm(md->bm, SUPERBLOCK_LOCATION,
 			       disk->metadata_space_map_root,
 			       sizeof(disk->metadata_space_map_root),
@@ -574,7 +583,6 @@ static int open_metadata(struct era_meta
 
 	setup_infos(md);
 
-	md->block_size = le32_to_cpu(disk->data_block_size);
 	md->nr_blocks = le32_to_cpu(disk->nr_blocks);
 	md->current_era = le32_to_cpu(disk->current_era);