[PATCH v3 08/13] btrfs: check for supported superblock checksum type before checksum validation

From: Johannes Thumshirn <jthumshirn@suse.de>
To: David Sterba <dsterba@suse.com>
Cc: Linux BTRFS Mailinglist <linux-btrfs@vger.kernel.org>,
	Chris Mason <clm@fb.com>, Richard Weinberger <richard@nod.at>,
	David Gstir <david@sigma-star.at>,
	Nikolay Borisov <nborisov@suse.com>,
	Johannes Thumshirn <jthumshirn@suse.de>
Subject: [PATCH v3 08/13] btrfs: check for supported superblock checksum type before checksum validation
Date: Wed, 22 May 2019 10:19:05 +0200	[thread overview]
Message-ID: <20190522081910.7689-9-jthumshirn@suse.de> (raw)
In-Reply-To: <20190522081910.7689-1-jthumshirn@suse.de>

Now that we have factorerd out the superblock checksum type validation, we
can check for supported superblock checksum types before doing the actual
validation of the superblock read from disk.

This leads the path to further simplifications of btrfs_check_super_csum()
later on.

Signed-off-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: Nikolay Borisov <nborisov@suse.com>

---
Changes to v2:
- Print on-disk checksum type if we encounter an unsupported type (David)
---
 fs/btrfs/disk-io.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 594583273782..f541d3c15d99 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -2821,6 +2821,16 @@ int open_ctree(struct super_block *sb,
 		goto fail_alloc;
 	}
 
+	if (!btrfs_supported_super_csum((struct btrfs_super_block *)
+					bh->b_data)) {
+		btrfs_err(fs_info, "unsupported checksum algorithm: %d",
+			  btrfs_super_csum_type((struct btrfs_super_block *)
+						bh->b_data));
+		err = -EINVAL;
+		brelse(bh);
+		goto fail_alloc;
+	}
+
 	/*
 	 * We want to check superblock checksum, the type is stored inside.
 	 * Pass the whole disk block of size BTRFS_SUPER_INFO_SIZE (4k).
-- 
2.16.4

