Re: [PATCH] xfs: limit superblock corruption errors to probable corruption

[Eric Sandeen <sandeen@redhat.com>]

On 1/30/14, 2:26 PM, Brian Foster wrote:
>> diff --git a/fs/xfs/xfs_sb.c b/fs/xfs/xfs_sb.c
>> > index 511cce9..b575317 100644
>> > --- a/fs/xfs/xfs_sb.c
>> > +++ b/fs/xfs/xfs_sb.c
>> > @@ -617,6 +617,8 @@ xfs_sb_read_verify(
>> >  			/* Only fail bad secondaries on a known V5 filesystem */
>> >  			if (bp->b_bn != XFS_SB_DADDR &&
>> >  			    xfs_sb_version_hascrc(&mp->m_sb)) {
>> > +				XFS_CORRUPTION_ERROR(__func__, XFS_ERRLEVEL_LOW,
>> > +						     mp, bp->b_addr);
>> >  				error = EFSCORRUPTED;
>> >  				goto out_error;
>> >  			}
>> > @@ -625,12 +627,8 @@ xfs_sb_read_verify(
>> >  	error = xfs_sb_verify(bp, true);
>> >  
>> >  out_error:
>> > -	if (error) {
>> > -		if (error != EWRONGFS)
>> > -			XFS_CORRUPTION_ERROR(__func__, XFS_ERRLEVEL_LOW,
>> > -					     mp, bp->b_addr);
>> > +	if (error)
>> >  		xfs_buf_ioerror(bp, error);
>> > -	}
>> >  }
> ... but why not leave the corruption output here in out_error, change
> the check to (error == EFSCORRUPTED) and remove the now duplicate
> corruption message in xfs_mount_validate_sb() (or replace it with a
> warn/notice message)? This would catch the other EFSCORRUPTED returns in
> a consistent manner, including another potential duplicate in the write
> verifier. I guess we'd lose a little specificity between the crc failure
> and sb validation, but we could add a warn/notice for the former too.
> 
> Brian
> 

Well, I went back and forth on this.  It's probably philosophical. ;)

Should we emit the corruption error at the point of corruption detection,
or at a higher level?  I guess my concern was that while *this* caller
might catch the return & yell, if another caller got added it might not.

Putting it at the point of detection seemed foolproof in that regard.

-Eric

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