Re: [PATCH] Btrfs: return EUCLEAN rather than ENXIO once internal error has occurred for SEEK_DATA/SEEK_HOLE inquiry

[Jeff Liu <jeff.liu@oracle.com>]

On 02/09/2012 12:51 PM, Dave Chinner wrote:

> On Thu, Feb 09, 2012 at 12:08:47PM +0800, Jeff Liu wrote:
>> On 02/09/2012 11:46 AM, Jeff Liu wrote:
>>
>>> By referring to http://linux.die.net/man/2/lseek, return ENXIO only
>>> when "offset beyond EOF" for either SEEK_DATA or SEEK_HOLE inquiry.
>>> But we return it in case of internal issue too if btrfs_get_extent_fiemap() failed
>>> due to other issues.  This will confuse the user applications to be expecting ENXIO when
>>> trying to find a specific data or hole location once it has occurred.
>>>
>>> Thanks Dave for pointing that out in XFS thread.
>>>
>>> This patch fix it to return EUCLEAN, or maybe another particular errno is more reasonable in Btrfs to indicate this fatal error?
>>
>> Or maybe just return the error that was happened at internal routine, to
>> give user more accurate error info, which is better?
> 
> Return the internal error unchanged - a failure to read the extent
> list (EIO) is different to a corruption detected in the extent
> map read from disk (EUCLEAN). Having a user report the appropriate
> error makes our life much simpler when it comes to trying to
> understand their problem....

Definitely. I will repost this patch later.

Thanks,
-Jeff

> 
> Cheers,
> 
> Dave.