Re: [PATCH V7 05/14] xfs: Check for extent overflow when adding/removing dir entries

Allison Henderson
2020-10-24T20:20:52Z

On 10/18/20 11:40 PM, Chandan Babu R wrote:
> Directory entry addition/removal 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.
>
Looks ok
Reviewed-by: Allison Henderson <allison.henderson@oracle.com>
> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
> Reviewed-by: Christoph Hellwig <hch@lst.de>
> Signed-off-by: Chandan Babu R <chandanrlinux@gmail.com>
> ---
> fs/xfs/libxfs/xfs_inode_fork.h | 13 +++++++++++++
> fs/xfs/xfs_inode.c | 27 +++++++++++++++++++++++++++
> fs/xfs/xfs_symlink.c | 5 +++++
> 3 files changed, 45 insertions(+)
>
> diff --git a/fs/xfs/libxfs/xfs_inode_fork.h b/fs/xfs/libxfs/xfs_inode_fork.h
> index 5de2f07d0dd5..fd93fdc67ee4 100644
> --- a/fs/xfs/libxfs/xfs_inode_fork.h
> +++ b/fs/xfs/libxfs/xfs_inode_fork.h
> @@ -57,6 +57,19 @@ struct xfs_ifork {
> #define XFS_IEXT_ATTR_MANIP_CNT(rmt_blks) \
> (XFS_DA_NODE_MAXDEPTH + max(1, rmt_blks))
>
> +/*
> + * Directory entry addition/removal 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 2bfbcf28b1bd..5b41ffaf04d7 100644
> --- a/fs/xfs/xfs_inode.c
> +++ b/fs/xfs/xfs_inode.c
> @@ -1177,6 +1177,11 @@ 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
> @@ -1393,6 +1398,11 @@ 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
> @@ -2861,6 +2871,11 @@ xfs_remove(
> xfs_trans_ijoin(tp, dp, XFS_ILOCK_EXCL);
> xfs_trans_ijoin(tp, ip, XFS_ILOCK_EXCL);
>
> + error = xfs_iext_count_may_overflow(dp, XFS_DATA_FORK,
> + XFS_IEXT_DIR_MANIP_CNT(mp));
> + if (error)
> + goto out_trans_cancel;
> +
> /*
> * If we're removing a directory perform some additional validation.
> */
> @@ -3221,6 +3236,18 @@ xfs_rename(
> if (wip)
> xfs_trans_ijoin(tp, wip, XFS_ILOCK_EXCL);
>
> + error = xfs_iext_count_may_overflow(src_dp, XFS_DATA_FORK,
> + XFS_IEXT_DIR_MANIP_CNT(mp));
> + if (error)
> + goto out_trans_cancel;
> +
> + if (target_ip == NULL) {
> + error = xfs_iext_count_may_overflow(target_dp, XFS_DATA_FORK,
> + XFS_IEXT_DIR_MANIP_CNT(mp));
> + if (error)
> + goto out_trans_cancel;
> + }
> +
> /*
> * If we are using project inheritance, we only allow renames
> * into our tree when the project IDs are the same; else the
> diff --git a/fs/xfs/xfs_symlink.c b/fs/xfs/xfs_symlink.c
> index 8e88a7ca387e..581a4032a817 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.
> */
>