ext4: fix uninit block bitmap initialization when s_meta_first_bg is non-zero

The number of old-style block group descriptor blocks is
s_meta_first_bg when the meta_bg feature flag is set.

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: stable@kernel.org

1 files changed, 7 insertions, 1 deletions

diff --git a/fs/ext4/balloc.c b/fs/ext4/balloc.c
index 1d0418980f8d..f3032c919a22 100644
--- a/fs/ext4/balloc.c
+++ b/fs/ext4/balloc.c
@@ -761,7 +761,13 @@ static unsigned long ext4_bg_num_gdb_meta(struct super_block *sb,
 static unsigned long ext4_bg_num_gdb_nometa(struct super_block *sb,
                                         ext4_group_t group)
 {
-        return ext4_bg_has_super(sb, group) ? EXT4_SB(sb)->s_gdb_count : 0;
+        if (!ext4_bg_has_super(sb, group))
+                return 0;
+
+        if (EXT4_HAS_INCOMPAT_FEATURE(sb,EXT4_FEATURE_INCOMPAT_META_BG))
+                return le32_to_cpu(EXT4_SB(sb)->s_es->s_first_meta_bg);
+        else
+                return EXT4_SB(sb)->s_gdb_count;
 }
 
 /**