On Thu, Feb 07, 2019 at 09:28:15AM -0500, Brian Foster wrote:
> 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:
It's set to NULL in the caller but I can move it to the top of
_map_prev to make the connection easier to find.
--D
> 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
> >
