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

diff --git a/fs/ext4/balloc.c b/fs/ext4/balloc.c
index 1d0418980f8db58e4ce34a3c47e00ee8bcb53d01..f3032c919a22dbee67f4d4d2f1f17269e69bac30 100644 (file)
--- 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;
 }
 
 /**