[PATCH 2/3] btrfs: Add csum type check for btrfs_check_super_valid()

[Qu Wenruo <wqu@suse.com>]

Just like incompat flags check, although we have already done super csum
type check before calling btrfs_check_super_valid(), we can still add
such check for later write time check.

Signed-off-by: Qu Wenruo <wqu@suse.com>
---
 fs/btrfs/disk-io.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index ec123158f051..b189ec086bc2 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -3981,6 +3981,15 @@ static int btrfs_check_super_valid(struct btrfs_fs_info *fs_info)
 	u64 sectorsize = btrfs_super_sectorsize(sb);
 	int ret = 0;
 
+	/*
+	 * For write time check, as for mount time we have checked csum before
+	 * calling btrfs_check_super_valid(), so it must be a corruption
+	 */
+	if (btrfs_super_csum_type(sb) >= ARRAY_SIZE(btrfs_csum_sizes)) {
+		btrfs_err(fs_info, "corrupted csum type %u",
+			  btrfs_super_csum_type(sb));
+		ret = -EINVAL;
+	}
 	if (btrfs_super_magic(sb) != BTRFS_MAGIC) {
 		btrfs_err(fs_info, "no valid FS found");
 		ret = -EINVAL;
-- 
2.17.0