Re: [PATCH V14 04/16] xfs: Check for extent overflow when adding dir entries

Darrick J. Wong
2021-01-12T01:34:48Z

On Sun, Jan 10, 2021 at 09:37:08PM +0530, Chandan Babu R wrote:
> Directory entry addition can cause the following,
> 1. Data block can be added/removed.
> A new extent can cause extent count to increase by 1.
> 2. Free disk block can be added/removed.
> Same behaviour as described above for Data block.
> 3. Dabtree blocks.
> XFS_DA_NODE_MAXDEPTH blocks can be added. Each of these
> can be new extents. Hence extent count can increase by
> XFS_DA_NODE_MAXDEPTH.
>
> Signed-off-by: Chandan Babu R <chandanrlinux@gmail.com>

OK, seems reasonably straight forward,
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>

--D

> ---
> fs/xfs/libxfs/xfs_inode_fork.h | 13 +++++++++++++
> fs/xfs/xfs_inode.c | 10 ++++++++++
> fs/xfs/xfs_symlink.c | 5 +++++
> 3 files changed, 28 insertions(+)
>
> diff --git a/fs/xfs/libxfs/xfs_inode_fork.h b/fs/xfs/libxfs/xfs_inode_fork.h
> index bcac769a7df6..ea1a9dd8a763 100644
> --- a/fs/xfs/libxfs/xfs_inode_fork.h
> +++ b/fs/xfs/libxfs/xfs_inode_fork.h
> @@ -47,6 +47,19 @@ struct xfs_ifork {
> */
> #define XFS_IEXT_PUNCH_HOLE_CNT (1)
>
> +/*
> + * Directory entry addition can cause the following,
> + * 1. Data block can be added/removed.
> + * A new extent can cause extent count to increase by 1.
> + * 2. Free disk block can be added/removed.
> + * Same behaviour as described above for Data block.
> + * 3. Dabtree blocks.
> + * XFS_DA_NODE_MAXDEPTH blocks can be added. Each of these can be new
> + * extents. Hence extent count can increase by XFS_DA_NODE_MAXDEPTH.
> + */
> +#define XFS_IEXT_DIR_MANIP_CNT(mp) \
> + ((XFS_DA_NODE_MAXDEPTH + 1 + 1) * (mp)->m_dir_geo->fsbcount)
> +
> /*
> * Fork handling.
> */
> diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c
> index b7352bc4c815..4cc787cc4eee 100644
> --- a/fs/xfs/xfs_inode.c
> +++ b/fs/xfs/xfs_inode.c
> @@ -1042,6 +1042,11 @@ xfs_create(
> if (error)
> goto out_trans_cancel;
>
> + error = xfs_iext_count_may_overflow(dp, XFS_DATA_FORK,
> + XFS_IEXT_DIR_MANIP_CNT(mp));
> + if (error)
> + goto out_trans_cancel;
> +
> /*
> * A newly created regular or special file just has one directory
> * entry pointing to them, but a directory also the "." entry
> @@ -1258,6 +1263,11 @@ xfs_link(
> xfs_trans_ijoin(tp, sip, XFS_ILOCK_EXCL);
> xfs_trans_ijoin(tp, tdp, XFS_ILOCK_EXCL);
>
> + error = xfs_iext_count_may_overflow(tdp, XFS_DATA_FORK,
> + XFS_IEXT_DIR_MANIP_CNT(mp));
> + if (error)
> + goto error_return;
> +
> /*
> * If we are using project inheritance, we only allow hard link
> * creation in our tree when the project IDs are the same; else
> diff --git a/fs/xfs/xfs_symlink.c b/fs/xfs/xfs_symlink.c
> index 1f43fd7f3209..0b8136a32484 100644
> --- a/fs/xfs/xfs_symlink.c
> +++ b/fs/xfs/xfs_symlink.c
> @@ -220,6 +220,11 @@ xfs_symlink(
> if (error)
> goto out_trans_cancel;
>
> + error = xfs_iext_count_may_overflow(dp, XFS_DATA_FORK,
> + XFS_IEXT_DIR_MANIP_CNT(mp));
> + if (error)
> + goto out_trans_cancel;
> +
> /*
> * Allocate an inode for the symlink.
> */
> --
> 2.29.2
>