On Wed, Feb 06, 2019 at 08:55:17AM -0800, Darrick J. Wong wrote:
> From: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
>
> There's a loop that searches an unlinked bucket list to find the inode
> that points to a given inode. Hoist this into a separate function;
> later we'll use our iunlink backref cache to bypass the slow list
> operation. No functional changes.
>
> Signed-off-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
> ---
> fs/xfs/xfs_inode.c | 135 +++++++++++++++++++++++++++++++++++++---------------
> 1 file changed, 96 insertions(+), 39 deletions(-)
>
>
> diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c
> index eb51fa33f91a..161d8da459aa 100644
> --- a/fs/xfs/xfs_inode.c
> +++ b/fs/xfs/xfs_inode.c
> @@ -2082,6 +2082,96 @@ xfs_iunlink(
> return xfs_iunlink_update_bucket(tp, agno, agibp, bucket_index, agino);
> }
>
...
> +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_mount *mp = tp->t_mountp;
> + xfs_agino_t next_agino;
> + int error;
> +
> + ASSERT(head_agino != target_agino);
> +
> + next_agino = head_agino;
> + while (next_agino != target_agino) {
> + xfs_agino_t unlinked_agino;
> +
> + if (*bpp)
> + xfs_trans_brelse(tp, *bpp);
Just because we have this check here, it might be appropriate to set
*bpp to NULL at the start of this function. Otherwise looks fine:
Reviewed-by: Brian Foster <bfoster@xxxxxxxxxx>
> +
> + *agino = next_agino;
> + error = xfs_iunlink_map_ino(tp, agno, next_agino, imap, dipp,
> + bpp);
> + if (error)
> + return error;
> +
> + unlinked_agino = be32_to_cpu((*dipp)->di_next_unlinked);
> + /*
> + * Make sure this pointer is valid and isn't an obvious
> + * infinite loop.
> + */
> + if (!xfs_verify_agino(mp, agno, unlinked_agino) ||
> + next_agino == unlinked_agino) {
> + XFS_CORRUPTION_ERROR(__func__,
> + XFS_ERRLEVEL_LOW, mp,
> + *dipp, sizeof(**dipp));
> + error = -EFSCORRUPTED;
> + return error;
> + }
> + next_agino = unlinked_agino;
> + }
> +
> + return 0;
> +}
> +
> /*
> * Pull the on-disk inode from the AGI unlinked list.
> */
> @@ -2093,9 +2183,8 @@ xfs_iunlink_remove(
> struct xfs_mount *mp = tp->t_mountp;
> struct xfs_agi *agi;
> struct xfs_buf *agibp;
> - struct xfs_buf *last_ibp;
> + struct xfs_buf *last_ibp = NULL;
> struct xfs_dinode *last_dip = NULL;
> - xfs_ino_t next_ino;
> xfs_agnumber_t agno = XFS_INO_TO_AGNO(mp, ip->i_ino);
> xfs_agino_t agino = XFS_INO_TO_AGINO(mp, ip->i_ino);
> xfs_agino_t next_agino;
> @@ -2138,43 +2227,11 @@ xfs_iunlink_remove(
> struct xfs_imap imap;
> xfs_agino_t prev_agino;
>
> - /*
> - * We need to search the list for the inode being freed.
> - */
> - last_ibp = NULL;
> - while (next_agino != agino) {
> - if (last_ibp)
> - xfs_trans_brelse(tp, last_ibp);
> -
> - imap.im_blkno = 0;
> - next_ino = XFS_AGINO_TO_INO(mp, agno, next_agino);
> -
> - error = xfs_imap(mp, tp, next_ino, &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, &last_dip,
> - &last_ibp, 0, 0);
> - if (error) {
> - xfs_warn(mp,
> - "%s: xfs_imap_to_bp returned error %d.",
> - __func__, error);
> - return error;
> - }
> -
> - prev_agino = next_agino;
> - next_agino = be32_to_cpu(last_dip->di_next_unlinked);
> - if (!xfs_verify_agino(mp, agno, next_agino)) {
> - XFS_CORRUPTION_ERROR(__func__,
> - XFS_ERRLEVEL_LOW, mp,
> - last_dip, sizeof(*last_dip));
> - return -EFSCORRUPTED;
> - }
> - }
> + /* We need to search the list for the inode being freed. */
> + error = xfs_iunlink_map_prev(tp, agno, next_agino, agino,
> + &prev_agino, &imap, &last_dip, &last_ibp);
> + if (error)
> + return error;
>
> /*
> * Now last_ibp points to the buffer previous to us on the
>
