On Nov 17, 2016, at 9:26 PM, Theodore Ts'o <tytso@xxxxxxx> wrote:
>
> 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@xxxxxxx>
Reviewed-by: Andreas Dilger <adilger@xxxxxxxxx>
> Cc: stable@xxxxxxxxxxxxxxx
> ---
> fs/ext4/super.c | 15 ++++++---------
> 1 file changed, 6 insertions(+), 9 deletions(-)
>
> diff --git a/fs/ext4/super.c b/fs/ext4/super.c
> index 3009c03220d6..6638a0415997 100644
> --- a/fs/ext4/super.c
> +++ b/fs/ext4/super.c
> @@ -3666,12 +3666,16 @@ 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);
> @@ -3754,13 +3758,6 @@ 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);
> --
> 2.11.0.rc0.7.gbe5a750
>
> --
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Cheers, Andreas
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