[PATCH 1/3] xfs: lock rt summary inode on allocation

[Eric Sandeen]

On 2/1/16 6:39 PM, Dave Chinner wrote:
> From: Dave Chinner <dchinner at redhat.com>
> 
> RT allocation can fail on a debug kernel with:
> 
> XFS: Assertion failed: xfs_isilocked(ip, XFS_ILOCK_SHARED|XFS_ILOCK_EXCL), file: fs/xfs/libxfs/xfs_bmap.c, line: 4039
> 
> When modifying the summary inode during allocation. This occurs
> because the summary inode is never locked, and xfs_bmapi_*
> operations expect it to be locked. The summary inode is effectively
> protected byt he lock on the bitmap inode, so this really is only a
> debug kernel issue.
> 
> Signed-off-by: Dave Chinner <dchinner at redhat.com>

Oh, it was easy after all...

Reviewed-by: Eric Sandeen <sandeen at redhat.com>

> ---
>  fs/xfs/xfs_bmap_util.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/fs/xfs/xfs_bmap_util.c b/fs/xfs/xfs_bmap_util.c
> index 7087756..fd7f51c 100644
> --- a/fs/xfs/xfs_bmap_util.c
> +++ b/fs/xfs/xfs_bmap_util.c
> @@ -202,10 +202,12 @@ xfs_bmap_rtalloc(
>  		ralen = MAXEXTLEN / mp->m_sb.sb_rextsize;
>  
>  	/*
> -	 * Lock out other modifications to the RT bitmap inode.
> +	 * Lock out modifications to both the RT bitmap and summary inodes
>  	 */
>  	xfs_ilock(mp->m_rbmip, XFS_ILOCK_EXCL);
>  	xfs_trans_ijoin(ap->tp, mp->m_rbmip, XFS_ILOCK_EXCL);
> +	xfs_ilock(mp->m_rsumip, XFS_ILOCK_EXCL);
> +	xfs_trans_ijoin(ap->tp, mp->m_rsumip, XFS_ILOCK_EXCL);
>  
>  	/*
>  	 * If it's an allocation to an empty file at offset 0,
>