On 2021/3/29 22:26, Jan Kara wrote:
> On Mon 29-03-21 14:19:55, Zhang Yi wrote:
>> Commit <50122847007> ("ext4: fix check to prevent initializing reserved
>> inodes") check the block group zero and prevent initializing reserved
>> inodes. But in some special cases, the reserved inode may not all belong
>> to the group zero, it may exist into the second group if we format
>> filesystem below.
>>
>> mkfs.ext4 -b 4096 -g 8192 -N 1024 -I 4096 /dev/sda
>>
>> So, it will end up triggering a false positive report of a corrupted
>> file system. This patch fix it by avoid check reserved inodes if no free
>> inode blocks will be zeroed.
>>
>> Fixes: 50122847007 ("ext4: fix check to prevent initializing reserved inodes")
>> Signed-off-by: Zhang Yi <yi.zhang@xxxxxxxxxx>
>
> Thanks! The patch looks correct but maybe the code can be made more
> comprehensible like I suggest below?
>
>> @@ -1543,22 +1544,25 @@ int ext4_init_inode_table(struct super_block *sb, ext4_group_t group,
>> * used inodes so we need to skip blocks with used inodes in
>> * inode table.
>> */
>> - if (!(gdp->bg_flags & cpu_to_le16(EXT4_BG_INODE_UNINIT)))
>> - used_blks = DIV_ROUND_UP((EXT4_INODES_PER_GROUP(sb) -
>> - ext4_itable_unused_count(sb, gdp)),
>> - sbi->s_inodes_per_block);
>> -
>> - if ((used_blks < 0) || (used_blks > sbi->s_itb_per_group) ||
>> - ((group == 0) && ((EXT4_INODES_PER_GROUP(sb) -
>> - ext4_itable_unused_count(sb, gdp)) <
>> - EXT4_FIRST_INO(sb)))) {
>> - ext4_error(sb, "Something is wrong with group %u: "
>> - "used itable blocks: %d; "
>> - "itable unused count: %u",
>> - group, used_blks,
>> - ext4_itable_unused_count(sb, gdp));
>> - ret = 1;
>> - goto err_out;
>> + if (!(gdp->bg_flags & cpu_to_le16(EXT4_BG_INODE_UNINIT))) {
>> + used_inos = EXT4_INODES_PER_GROUP(sb) -
>> + ext4_itable_unused_count(sb, gdp);
>> + used_blks = DIV_ROUND_UP(used_inos, sbi->s_inodes_per_block);
>> +
>> + if (used_blks >= 0 && used_blks <= sbi->s_itb_per_group)
>> + used_inos += group * EXT4_INODES_PER_GROUP(sb);
>
> Maybe if would be more comprehensible like:
>
> /* Bogus inode unused count? */
> if (used_blks < 0 || used_blks > sbi->s_itb_per_group) {
> ext4_error(...);
> ret = 1;
> goto err_out;
> }
>
> used_inos += EXT4_INODES_PER_GROUP(sb);
> /*
> * Are there some uninitialized inodes in the inode table
> * before the first normal inode?
> */
> if (used_blks != sbi->s_itb_per_group &&
> used_inos < EXT4_FIRST_INO(sb)) {
> ext4_error(...);
> ret = 1;
> goto err_out;
> }
Yes, it looks more comprehensible, I will send v2 as you suggested.
Thanks,
Yi.
