Re: [PATCH v2 02/14] btrfs-progs: check: introduce function to find dir_item

[Qu Wenruo <quwenruo@cn.fujitsu.com>]

At 11/02/2016 11:21 PM, David Sterba wrote:
> On Wed, Sep 21, 2016 at 11:15:52AM +0800, Qu Wenruo wrote:
>> From: Lu Fengqi <lufq.fnst@cn.fujitsu.com>
>>
>> Introduce a new function find_dir_item() to find DIR_ITEM for the given
>> key, and check it with the specified INODE_REF/INODE_EXTREF match.
>>
>> Signed-off-by: Lu Fengqi <lufq.fnst@cn.fujitsu.com>
>> Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
>> ---
>>  cmds-check.c | 140 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
>>  1 file changed, 140 insertions(+)
>>
>> diff --git a/cmds-check.c b/cmds-check.c
>> index 998ba63..4e25804 100644
>> --- a/cmds-check.c
>> +++ b/cmds-check.c
>> @@ -3848,6 +3848,146 @@ out:
>>  	return err;
>>  }
>>
>> +#define ROOT_DIR_ERROR		(1<<1)	/* bad root_dir */
>> +#define DIR_ITEM_MISSING	(1<<2)	/* DIR_ITEM not found */
>> +#define DIR_ITEM_MISMATCH	(1<<3)	/* DIR_ITEM found but not match */
>
> What's the reason for another definition of the error codes? They're
> mostly copied from te I_ERR_* counterparts. I'd rather have one set of
> error codes.

The main reason is, in lowmem fsck mode, we are not checking inodes or 
ref/backref in batch.

If using I_ERR and REF_ERR, we can mixing them up as they share the same 
bits.

So we introduced the new error bitmap, to make sure all error bits won't 
cover each other.

It may be better if we rearrange I_ERR/REF_ERR to avoid conflicts.
E.g, let REF_ERR_ starts from lowest bit and let I_ERR_ starts from high 
bits.

Thanks,
Qu