[PATCH 4.9 053/329] btrfs: fail mount when sb flag is not in BTRFS_SUPER_FLAG_SUPP

[Greg Kroah-Hartman]

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

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

From: Anand Jain <Anand.Jain@xxxxxxxxxx>

[ Upstream commit 6f794e3c5c8f8fdd3b5bb20d9ded894e685b5bbe ]

It appears from the original commit [1] that there isn't any design
specific reason not to fail the mount instead of just warning. This
patch will change it to fail.

[1]
 commit 319e4d0661e5323c9f9945f0f8fb5905e5fe74c3
    btrfs: Enhance super validation check

Fixes: 319e4d0661e5323 ("btrfs: Enhance super validation check")
Signed-off-by: Anand Jain <anand.jain@xxxxxxxxxx>
Reviewed-by: Qu Wenruo <wqu@xxxxxxxx>
Reviewed-by: David Sterba <dsterba@xxxxxxxx>
Signed-off-by: David Sterba <dsterba@xxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 fs/btrfs/disk-io.c |    6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -4142,9 +4142,11 @@ static int btrfs_check_super_valid(struc
 		btrfs_err(fs_info, "no valid FS found");
 		ret = -EINVAL;
 	}
-	if (btrfs_super_flags(sb) & ~BTRFS_SUPER_FLAG_SUPP)
-		btrfs_warn(fs_info, "unrecognized super flag: %llu",
+	if (btrfs_super_flags(sb) & ~BTRFS_SUPER_FLAG_SUPP) {
+		btrfs_err(fs_info, "unrecognized or unsupported super flag: %llu",
 				btrfs_super_flags(sb) & ~BTRFS_SUPER_FLAG_SUPP);
+		ret = -EINVAL;
+	}
 	if (btrfs_super_root_level(sb) >= BTRFS_MAX_LEVEL) {
 		btrfs_err(fs_info, "tree_root level too big: %d >= %d",
 				btrfs_super_root_level(sb), BTRFS_MAX_LEVEL);