[PATCH RFC 00/17] ubifs: Add filesystem repair support

[Zhihao Cheng]

在 2024/1/3 11:18, Zhihao Cheng 写道:
> 在 2024/1/3 4:45, Richard Weinberger 写道:
>> ----- Ursprüngliche Mail -----
>>> Von: "chengzhihao1" <chengzhihao1 at huawei.com>
>>> I come up with another way to implement fsck.ubifs:
>>>
>>> There are three modes:
>>>
>>> 1. common mode(no options): Ask user whether to fix as long as a problem
>>> is detected.
>>
>> Makes sense.
>>
>>> 2. safe mode(-a option): Auto repair as long as no data/files lost(eg.
>>> nlink, isize, xattr_cnt, which can be corrected without dropping nodes),
>>> otherwise returns error code.
>>
>> Makes sense.
>>> 3. dangerous mode(-y option): Fix is always successful, unless
>>> superblock is corrupted. There are 2 situations:
>>
>> Please not use "-y". Usually "-y" stands for "answer yes to all 
>> questions".
>> But selecting names for command line flags is currently my least concern.
>>>    a) TNC is valid: fsck will print which file is dropped and which
>>> file's data is dropped
>>
>> Sounds also good.
>>>    b) TNC is invalid: fsck will scan all nodes without referencing TNC,
>>> same as this patchset does
>>
>> I'd make this a distinct mode.
>> It can be used to rebuild index and LEB property trees.
>> This is basically a "drop trees and rebuild" mode.
>>
> 
> OK, then fsck will have four modes.

How about merging 3(a) and 3(b) as one mode(dangerous mode)? If fsck can 
get a good TNC(all non-leaf index nodes are valid), fsck executes as 
3(a) describes. If fsck cannot find a good TNC, fsck executes as 3(b) 
and reminds user that "TNC is damaged, nodes dropping is not awared".