Re: [PATCH 6/8] xfs: fix uninitialized field in rtbitmap fsmap backend

[Christoph Hellwig <hch@infradead.org>]

On Thu, Jun 21, 2018 at 11:31:41AM -0700, Darrick J. Wong wrote:
> From: Darrick J. Wong <darrick.wong@oracle.com>
> 
> Initialize the extent count field of the high key so that when we use
> the high key to synthesize an 'unknown owner' record (i.e. used space
> record) at the end of the queried range we have a field with which to
> compute rm_blockcount.  This is not strictly necessary because the
> synthesizer never uses the rm_blockcount field, but we can shut up the
> static code analysis anyway.
> 
> Coverity-id: 1437358
> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>

I'd rather ensure the structs are entirely zeroed to start with, e.g.:

diff --git a/fs/xfs/xfs_fsmap.c b/fs/xfs/xfs_fsmap.c
index 0299febece9c..21bbdee451a6 100644
--- a/fs/xfs/xfs_fsmap.c
+++ b/fs/xfs/xfs_fsmap.c
@@ -527,8 +527,8 @@ xfs_getfsmap_rtdev_rtbitmap_query(
 	struct xfs_trans		*tp,
 	struct xfs_getfsmap_info	*info)
 {
-	struct xfs_rtalloc_rec		alow;
-	struct xfs_rtalloc_rec		ahigh;
+	struct xfs_rtalloc_rec		alow = { 0, };
+	struct xfs_rtalloc_rec		ahigh = { 0, };
 	int				error;
 
 	xfs_ilock(tp->t_mountp->m_rbmip, XFS_ILOCK_SHARED);