Re: [PATCH v2 2/3] xfs: clean up xfs_bui_item_recover iget/trans_alloc/ilock ordering

[Dave Chinner <david@fromorbit.com>]

On Thu, Sep 17, 2020 at 12:08:02AM -0700, Darrick J. Wong wrote:
> From: Darrick J. Wong <darrick.wong@oracle.com>
> 
> In most places in XFS, we have a specific order in which we gather
> resources: grab the inode, allocate a transaction, then lock the inode.
> xfs_bui_item_recover doesn't do it in that order, so fix it to be more
> consistent.  This also makes the error bailout code a bit less weird.
> 
> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
> ---
> v2: fix the error-out paths to free the BUI if the BUD hasn't been
> created
> ---
>  fs/xfs/xfs_bmap_item.c |   49 +++++++++++++++++++++++++-----------------------
>  1 file changed, 26 insertions(+), 23 deletions(-)
> 
> diff --git a/fs/xfs/xfs_bmap_item.c b/fs/xfs/xfs_bmap_item.c
> index 4e5aa29f75b7..f088cfd495bd 100644
> --- a/fs/xfs/xfs_bmap_item.c
> +++ b/fs/xfs/xfs_bmap_item.c
> @@ -432,7 +432,7 @@ xfs_bui_item_recover(
>  	struct xfs_inode		*ip = NULL;
>  	struct xfs_mount		*mp = lip->li_mountp;
>  	struct xfs_map_extent		*bmap;
> -	struct xfs_bud_log_item		*budp;
> +	struct xfs_bud_log_item		*budp = NULL;
>  	xfs_fsblock_t			startblock_fsb;
>  	xfs_fsblock_t			inode_fsb;
>  	xfs_filblks_t			count;
> @@ -475,27 +475,26 @@ xfs_bui_item_recover(
>  	    (bmap->me_flags & ~XFS_BMAP_EXTENT_FLAGS))
>  		goto garbage;
>  
> -	error = xfs_trans_alloc(mp, &M_RES(mp)->tr_itruncate,
> -			XFS_EXTENTADD_SPACE_RES(mp, XFS_DATA_FORK), 0, 0, &tp);
> -	if (error) {
> -		xfs_bui_release(buip);
> -		return error;
> -	}
> -
> -	budp = xfs_trans_get_bud(tp, buip);
> -
>  	/* Grab the inode. */
> -	error = xfs_iget(mp, tp, bmap->me_owner, 0, XFS_ILOCK_EXCL, &ip);
> +	error = xfs_iget(mp, NULL, bmap->me_owner, 0, 0, &ip);
>  	if (error)
> -		goto err_inode;
> +		goto err_bui;

err_bui could be combined with the garbage error return if error is
initialised to -EFSCORRUPTED.

Otherwise it looks OK.

Reviewed-by: Dave Chinner <dchinner@redhat.com>

Cheers,

Dave.
-- 
Dave Chinner
david@fromorbit.com