Re: [PATCH 07/13] xfs: mapping unlinked inodes is now redundant

Darrick J. Wong
2020-08-19T00:17:01Z

On Wed, Aug 12, 2020 at 07:25:50PM +1000, Dave Chinner wrote:
> From: Dave Chinner <dchinner@redhat.com>
>
> We now have a direct pointer to the xfs_inodes in the unlinked
> lists, so we can use the imap built into the inode to read the
> underlying cluster buffer. Hence we can remove all the "lookup by
> agino" code that currently exists in the iunlink list processing.
>
> Signed-off-by: Dave Chinner <dchinner@redhat.com>

Looks pretty simple,
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>

--D

> ---
> fs/xfs/xfs_inode.c | 88 ++++++----------------------------------------
> 1 file changed, 10 insertions(+), 78 deletions(-)
>
> diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c
> index 2c930de99561..bacd5ae9f5a7 100644
> --- a/fs/xfs/xfs_inode.c
> +++ b/fs/xfs/xfs_inode.c
> @@ -2139,74 +2139,6 @@ xfs_iunlink(
> return error;
> }
>
> -/* Return the imap, dinode pointer, and buffer for an inode. */
> -STATIC int
> -xfs_iunlink_map_ino(
> - struct xfs_trans *tp,
> - xfs_agnumber_t agno,
> - xfs_agino_t agino,
> - struct xfs_imap *imap,
> - struct xfs_dinode **dipp,
> - struct xfs_buf **bpp)
> -{
> - struct xfs_mount *mp = tp->t_mountp;
> - int error;
> -
> - imap->im_blkno = 0;
> - error = xfs_imap(mp, tp, XFS_AGINO_TO_INO(mp, agno, agino), imap, 0);
> - if (error) {
> - xfs_warn(mp, "%s: xfs_imap returned error %d.",
> - __func__, error);
> - return error;
> - }
> -
> - error = xfs_imap_to_bp(mp, tp, imap, dipp, bpp, 0);
> - if (error) {
> - xfs_warn(mp, "%s: xfs_imap_to_bp returned error %d.",
> - __func__, error);
> - return error;
> - }
> -
> - return 0;
> -}
> -
> -/*
> - * Walk the unlinked chain from @head_agino until we find the inode that
> - * points to @target_agino. Return the inode number, map, dinode pointer,
> - * and inode cluster buffer of that inode as @agino, @imap, @dipp, and @bpp.
> - *
> - * @tp, @pag, @head_agino, and @target_agino are input parameters.
> - * @agino, @imap, @dipp, and @bpp are all output parameters.
> - *
> - * Do not call this function if @target_agino is the head of the list.
> - */
> -STATIC int
> -xfs_iunlink_map_prev(
> - struct xfs_trans *tp,
> - xfs_agnumber_t agno,
> - xfs_agino_t head_agino,
> - xfs_agino_t target_agino,
> - xfs_agino_t agino,
> - struct xfs_imap *imap,
> - struct xfs_dinode **dipp,
> - struct xfs_buf **bpp,
> - struct xfs_perag *pag)
> -{
> - int error;
> -
> - ASSERT(head_agino != target_agino);
> - *bpp = NULL;
> -
> - ASSERT(agino != NULLAGINO);
> - error = xfs_iunlink_map_ino(tp, agno, agino, imap, dipp, bpp);
> - if (error)
> - return error;
> -
> - if (be32_to_cpu((*dipp)->di_next_unlinked) != target_agino)
> - return -EFSCORRUPTED;
> - return 0;
> -}
> -
> static int
> xfs_iunlink_remove_inode(
> struct xfs_trans *tp,
> @@ -2215,8 +2147,6 @@ xfs_iunlink_remove_inode(
> {
> struct xfs_mount *mp = tp->t_mountp;
> struct xfs_agi *agi;
> - struct xfs_buf *last_ibp;
> - struct xfs_dinode *last_dip = NULL;
> xfs_agino_t agino = XFS_INO_TO_AGINO(mp, ip->i_ino);
> xfs_agnumber_t agno = XFS_INO_TO_AGNO(mp, ip->i_ino);
> xfs_agino_t next_agino;
> @@ -2260,25 +2190,27 @@ xfs_iunlink_remove_inode(
> if (ip != list_first_entry(&agibp->b_pag->pag_ici_unlink_list,
> struct xfs_inode, i_unlink)) {
>
> - struct xfs_inode *pip;
> - struct xfs_imap imap;
> - xfs_agino_t prev_agino;
> + struct xfs_inode *pip;
> + xfs_agino_t prev_agino;
> + struct xfs_buf *last_ibp;
> + struct xfs_dinode *last_dip = NULL;
>
> ASSERT(head_agino != agino);
>
> pip = list_prev_entry(ip, i_unlink);
> prev_agino = XFS_INO_TO_AGINO(mp, pip->i_ino);
>
> - /* We need to search the list for the inode being freed. */
> - error = xfs_iunlink_map_prev(tp, agno, head_agino, agino,
> - prev_agino, &imap, &last_dip, &last_ibp,
> - agibp->b_pag);
> + error = xfs_imap_to_bp(mp, tp, &pip->i_imap, &last_dip,
> + &last_ibp, 0);
> if (error)
> return error;
>
> + if (be32_to_cpu(last_dip->di_next_unlinked) != agino)
> + return -EFSCORRUPTED;
> +
> /* Point the previous inode on the list to the next inode. */
> xfs_iunlink_update_dinode(tp, agno, prev_agino, last_ibp,
> - last_dip, &imap, next_agino);
> + last_dip, &pip->i_imap, next_agino);
>
> return 0;
> }
> --
> 2.26.2.761.g0e0b3e54be
>