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

Eric Sandeen
2016-02-02T01:26:53Z

On 2/1/16 6:39 PM, Dave Chinner wrote:
> From: Dave Chinner <dchinner@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@redhat.com>

Oh, it was easy after all...

Reviewed-by: Eric Sandeen <sandeen@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,