Re: [PATCH V7 09/14] xfs: Check for extent overflow when swapping extents

Allison Henderson
2020-10-24T20:41:53Z

On 10/18/20 11:40 PM, Chandan Babu R wrote:
> Removing an initial range of source/donor file's extent and adding a new
> extent (from donor/source file) in its place will cause extent count to
> increase by 1.
>
Looks ok to me
Reviewed-by: Allison Henderson <allison.henderson@oracle.com>

> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
> Signed-off-by: Chandan Babu R <chandanrlinux@gmail.com>
> ---
> fs/xfs/libxfs/xfs_inode_fork.h | 7 +++++++
> fs/xfs/xfs_bmap_util.c | 16 ++++++++++++++++
> 2 files changed, 23 insertions(+)
>
> diff --git a/fs/xfs/libxfs/xfs_inode_fork.h b/fs/xfs/libxfs/xfs_inode_fork.h
> index b99e67e7b59b..969b06160d44 100644
> --- a/fs/xfs/libxfs/xfs_inode_fork.h
> +++ b/fs/xfs/libxfs/xfs_inode_fork.h
> @@ -87,6 +87,13 @@ struct xfs_ifork {
> */
> #define XFS_IEXT_REFLINK_END_COW_CNT (2)
>
> +/*
> + * Removing an initial range of source/donor file's extent and adding a new
> + * extent (from donor/source file) in its place will cause extent count to
> + * increase by 1.
> + */
> +#define XFS_IEXT_SWAP_RMAP_CNT (1)
> +
> /*
> * Fork handling.
> */
> diff --git a/fs/xfs/xfs_bmap_util.c b/fs/xfs/xfs_bmap_util.c
> index 0776abd0103c..b6728fdf50ae 100644
> --- a/fs/xfs/xfs_bmap_util.c
> +++ b/fs/xfs/xfs_bmap_util.c
> @@ -1407,6 +1407,22 @@ xfs_swap_extent_rmap(
> irec.br_blockcount);
> trace_xfs_swap_extent_rmap_remap_piece(tip, &uirec);
>
> + if (xfs_bmap_is_real_extent(&uirec)) {
> + error = xfs_iext_count_may_overflow(ip,
> + XFS_DATA_FORK,
> + XFS_IEXT_SWAP_RMAP_CNT);
> + if (error)
> + goto out;
> + }
> +
> + if (xfs_bmap_is_real_extent(&irec)) {
> + error = xfs_iext_count_may_overflow(tip,
> + XFS_DATA_FORK,
> + XFS_IEXT_SWAP_RMAP_CNT);
> + if (error)
> + goto out;
> + }
> +
> /* Remove the mapping from the donor file. */
> xfs_bmap_unmap_extent(tp, tip, &uirec);
>
>