On 2025/3/26 10:16, Baokun Li wrote:
> On 2025/3/26 1:57, Ojaswin Mujoo wrote:
>> On Tue, Mar 18, 2025 at 10:31:29PM -0400, Theodore Ts'o wrote:
>>> On Tue, Mar 18, 2025 at 01:42:31PM +0530, Ojaswin Mujoo wrote:
>>>>> So this is something we need to do if the journal is actived, and if
>>>>> it's active, then sbi->s_journal will be non-NULL, and so we can just
>>>>> check to see if inode == sbi->s_journal instead. This will simplify
>>>> I believe you mean inode == sbi->s_journal->j_inode here right?
>>> Yes, that's what I meant; sorry for the not catching this before I
>>> sent my reply.
>>>
>>> Cheers,
>>>
>>> - Ted
>> Hi Ted, Baokun,
>>
>> I got some time to revisit this. Seems like checking against
>> s_journal->j_inode is not enough. This is because both
>> ext4_check_blockref() and check_block_validity() can be called even
>> before journal->j_inode is set:
>>
>> ext4_open_inode_journal
>> ext4_get_journal_inode
>> __ext4_iget
>> ext4_ind_check_inode
>> ext4_check_blockref /* j_inode not set */
>>
>> journal = jbd2_journal_init_inode
>> bmap
>> ext4_bmap
>> iomap_bmap
>> ext4_iomap_begin
>> ext4_map_blocks
>> check_block_validity
>>
>> journal->j_inode = inode
>>
>>
>> Now, I think in this case the best solution might be to use the extra
>> field like we do in this patch but set EXT4_SB(sb)->s_journal_ino
>> sufficiently early.
>>
>> Thoughts?
>
> Because system zone setup happens after the journal are loaded, I think we
> can skip the check if the journal haven't been loaded yet, like this:
>
> diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
> index d04d8a7f12e7..38dc72ff7e78 100644
> --- a/fs/ext4/inode.c
> +++ b/fs/ext4/inode.c
> @@ -383,9 +383,10 @@ static int __check_block_validity(struct inode *inode, const char *func,
> unsigned int line,
> struct ext4_map_blocks *map)
> {
> + journal_t *journal = EXT4_SB(inode->i_sb)->s_journal;
> +
> if (ext4_has_feature_journal(inode->i_sb) &&
> - (inode->i_ino ==
> - le32_to_cpu(EXT4_SB(inode->i_sb)->s_es->s_journal_inum)))
> + (!journal || inode == journal->j_inode))
> return 0;
> if (!ext4_inode_block_valid(inode, map->m_pblk, map->m_len)) {
> ext4_error_inode(inode, func, line, map->m_pblk,
>
> If any part of the journal area overlaps with the system zone, we'll catch
> it when we add the journal area to the system zone later.
>
>
Since the creation of the system zone relies on the journal being
loaded, I think there is no risk in proceeding to call
ext4_inode_block_valid() to perform a basic block range check for
the journal inode, or even better.
Thanks,
Yi.
