Re: [PATCH 2/2] xfs: check da node magic in _node_lookup_int

["Darrick J. Wong" <darrick.wong@oracle.com>]

On Wed, Aug 01, 2018 at 02:12:02PM +0200, Carlos Maiolino wrote:
> On Tue, Jul 31, 2018 at 04:21:00PM -0700, Darrick J. Wong wrote:
> > From: Darrick J. Wong <darrick.wong@oracle.com>
> > 
> > Before we start processing what we /think/ is a da3 node block, actually
> > check the magic to make sure that we're looking at a node block.  This
> > way we won't blow the asserts in _node_hdr_from_disk on corrupted
> > metadata.
> > 
> > Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
> 
> The patch looks good, but why wouldn't merge it into the previous one?
> 
> Both patches look reasonable to fit into a single one.
> 
> But, merging both or not.

They're different logical changes to the source code -- one refactors to
use a local variable, the other adds extra checks.

--D

> Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com>
> 
> > ---
> >  fs/xfs/libxfs/xfs_da_btree.c |    4 +++-
> >  1 file changed, 3 insertions(+), 1 deletion(-)
> > 
> > 
> > diff --git a/fs/xfs/libxfs/xfs_da_btree.c b/fs/xfs/libxfs/xfs_da_btree.c
> > index 8ffe17b223da..376bee94b5dd 100644
> > --- a/fs/xfs/libxfs/xfs_da_btree.c
> > +++ b/fs/xfs/libxfs/xfs_da_btree.c
> > @@ -1523,8 +1523,10 @@ xfs_da3_node_lookup_int(
> >  			break;
> >  		}
> >  
> > -		blk->magic = XFS_DA_NODE_MAGIC;
> > +		if (magic != XFS_DA_NODE_MAGIC && magic != XFS_DA3_NODE_MAGIC)
> > +			return -EFSCORRUPTED;
> >  
> > +		blk->magic = XFS_DA_NODE_MAGIC;
> >  
> >  		/*
> >  		 * Search an intermediate node for a match.
> > 
> > --
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> 
> -- 
> Carlos
> --
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