ext4: avoid divide by zero when trying to mount a corrupted file system

[karo-tx-linux.git] / fs / ext4 / super.c

diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index d4ca92aab51411de0bab1bf8824e9aa8974b8d17..8662b2e6e9f9f4abc4a8b5738745e66f4f3f93ce 100644 (file)
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -1673,14 +1673,14 @@ static int ext4_fill_flex_info(struct super_block *sb)
        size_t size;
        int i;
 
-       if (!sbi->s_es->s_log_groups_per_flex) {
+       sbi->s_log_groups_per_flex = sbi->s_es->s_log_groups_per_flex;
+       groups_per_flex = 1 << sbi->s_log_groups_per_flex;
+
+       if (groups_per_flex < 2) {
                sbi->s_log_groups_per_flex = 0;
                return 1;
        }
 
-       sbi->s_log_groups_per_flex = sbi->s_es->s_log_groups_per_flex;
-       groups_per_flex = 1 << sbi->s_log_groups_per_flex;
-
        /* We allocate both existing and potentially added groups */
        flex_group_count = ((sbi->s_groups_count + groups_per_flex - 1) +
                        ((le16_to_cpu(sbi->s_es->s_reserved_gdt_blocks) + 1) <<