[Ocfs2-devel] [PATCH] ocfs2: return -EROFS to upper if inode block is invalid

[piaojun]

Hi Joseph,

On 2017/12/26 14:10, Joseph Qi wrote:
> 
> 
> On 17/12/26 13:35, piaojun wrote:
>> Hi Joseph,
>>
>> On 2017/12/26 11:05, Joseph Qi wrote:
>>>
>>>
>>> On 17/12/26 10:11, piaojun wrote:
>>>> If metadata is corrupted such as 'invalid inode block', we will get
>>>> failed by calling 'mount()' as below:
>>>>
>>>> ocfs2_mount
>>>>   ocfs2_initialize_super
>>>>     ocfs2_init_global_system_inodes : return -EINVAL if inode is NULL
>>>>       ocfs2_get_system_file_inode
>>>>         _ocfs2_get_system_file_inode : return NULL if inode is errno
>>> Do you mean inode is bad?
>>>
>> Here we have to face two abnormal cases:
>> 1. inode is bad;
>> 2. read inode from disk failed due to bad storage link.
>>>>           ocfs2_iget
>>>>             ocfs2_read_locked_inode
>>>>               ocfs2_validate_inode_block
>>>>
>>>> In this situation we need return -EROFS to upper application, so that
>>>> user can fix it by fsck. And then mount again.
>>>>
>>>> Signed-off-by: Jun Piao <piaojun at huawei.com>
>>>> Reviewed-by: Alex Chen <alex.chen at huawei.com>
>>>> ---
>>>>  fs/ocfs2/super.c | 10 ++++++++--
>>>>  1 file changed, 8 insertions(+), 2 deletions(-)
>>>>
>>>> diff --git a/fs/ocfs2/super.c b/fs/ocfs2/super.c
>>>> index 040bbb6..dea21a7 100644
>>>> --- a/fs/ocfs2/super.c
>>>> +++ b/fs/ocfs2/super.c
>>>> @@ -474,7 +474,10 @@ static int ocfs2_init_global_system_inodes(struct ocfs2_super *osb)
>>>>  		new = ocfs2_get_system_file_inode(osb, i, osb->slot_num);
>>>>  		if (!new) {
>>>>  			ocfs2_release_system_inodes(osb);
>>>> -			status = -EINVAL;
>>>> +			if (ocfs2_is_soft_readonly(osb))
>>> I'm afraid that having bad inode doesn't means ocfs2 is readonly.
>>> And the calling application is mount.ocfs2. So do you mean mount.ocfs2
>>> have to handle EROFS like printing corresponding error log?
>>>
>> I agree that 'bad inode' also means other abnormal cases like
>> 'bad storage link' or 'no memory', but we can distinguish that by
>> ocfs2_is_soft_readonly(). I found that 'mount.ocfs2' did not
>> distinguish any error type and just return 1 for all error cases. I
>> wonder if we should return the exact errno for users?
>> Soft readonly is an in-memory status. The case you described is just
> trying to read inode and then check if it is bad. So where to set the
> status before?
> 
we set readonly status in the following process:
ocfs2_validate_inode_block()
  ocfs2_error
    ocfs2_handle_error
      ocfs2_set_ro_flag(osb, 0);

I have a suggestion that we could distinguish readonly status in
'mount.ocfs2', and return -EROFS to users so that they can fix it.
>> thanks,
>> Jun
>>
>>>> +				status = -EROFS;
>>>> +			else
>>>> +				status = -EINVAL;
>>>>  			mlog_errno(status);
>>>>  			/* FIXME: Should ERROR_RO_FS */
>>>>  			mlog(ML_ERROR, "Unable to load system inode %d, "
>>>> @@ -505,7 +508,10 @@ static int ocfs2_init_local_system_inodes(struct ocfs2_super *osb)
>>>>  		new = ocfs2_get_system_file_inode(osb, i, osb->slot_num);
>>>>  		if (!new) {
>>>>  			ocfs2_release_system_inodes(osb);
>>>> -			status = -EINVAL;
>>>> +			if (ocfs2_is_soft_readonly(osb))
>>>> +				status = -EROFS;
>>>> +			else
>>>> +				status = -EINVAL;
>>>>  			mlog(ML_ERROR, "status=%d, sysfile=%d, slot=%d\n",
>>>>  			     status, i, osb->slot_num);
>>>>  			goto bail;
>>>>
>>> .
>>>
> .
>