ext4: use more strict checks for inodes_per_block on mount

Centralize the checks for inodes_per_block and be more strict to make
sure the inodes_per_block_group can't end up being zero.

Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Andreas Dilger <adilger@dilger.ca>
Cc: stable@vger.kernel.org

diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 404e6f3c1bed765c3569c4e76fc95c8927def1d9..689c02df1af4eb6303e5fb5263e05a0dbbee4521 100644 (file)
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -3668,12 +3668,16 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
 
        sbi->s_blocks_per_group = le32_to_cpu(es->s_blocks_per_group);
        sbi->s_inodes_per_group = le32_to_cpu(es->s_inodes_per_group);
-       if (EXT4_INODE_SIZE(sb) == 0 || EXT4_INODES_PER_GROUP(sb) == 0)
-               goto cantfind_ext4;
 
        sbi->s_inodes_per_block = blocksize / EXT4_INODE_SIZE(sb);
        if (sbi->s_inodes_per_block == 0)
                goto cantfind_ext4;
+       if (sbi->s_inodes_per_group < sbi->s_inodes_per_block ||
+           sbi->s_inodes_per_group > blocksize * 8) {
+               ext4_msg(sb, KERN_ERR, "invalid inodes per group: %lu\n",
+                        sbi->s_blocks_per_group);
+               goto failed_mount;
+       }
        sbi->s_itb_per_group = sbi->s_inodes_per_group /
                                        sbi->s_inodes_per_block;
        sbi->s_desc_per_block = blocksize / EXT4_DESC_SIZE(sb);
@@ -3756,13 +3760,6 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
        }
        sbi->s_cluster_ratio = clustersize / blocksize;
 
-       if (sbi->s_inodes_per_group > blocksize * 8) {
-               ext4_msg(sb, KERN_ERR,
-                      "#inodes per group too big: %lu",
-                      sbi->s_inodes_per_group);
-               goto failed_mount;
-       }
-
        /* Do we have standard group size of clustersize * 8 blocks ? */
        if (sbi->s_blocks_per_group == clustersize << 3)
                set_opt2(sb, STD_GROUP_SIZE);