xfs: remove all boilerplate defer init/finish code

At this point, the transaction subsystem completely manages deferred
items internally such that the common and boilerplate
xfs_trans_alloc() -> xfs_defer_init() -> xfs_defer_finish() ->
xfs_trans_commit() sequence can be replaced with a simple
transaction allocation and commit.

Remove all such boilerplate deferred ops code. In doing so, we
change each case over to use the dfops in the transaction and
specifically eliminate:

- The on-stack dfops and associated xfs_defer_init() call, as the
  internal dfops is initialized on transaction allocation.
- xfs_bmap_finish() calls that precede a final xfs_trans_commit() of
  a transaction.
- xfs_defer_cancel() calls in error handlers that precede a
  transaction cancel.

The only deferred ops calls that remain are those that are
non-deterministic with respect to the final commit of the associated
transaction or are open-coded due to special handling.

Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Bill O'Donnell <billodo@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>

2 files changed, 2 insertions, 24 deletions

diff --git a/fs/xfs/libxfs/xfs_bmap.c b/fs/xfs/libxfs/xfs_bmap.c
index 6bc0cdff488e..92cd064a2589 100644
--- a/fs/xfs/libxfs/xfs_bmap.c
+++ b/fs/xfs/libxfs/xfs_bmap.c
@@ -1018,7 +1018,6 @@ xfs_bmap_add_attrfork(
 	int			size,		/* space new attribute needs */
 	int			rsvd)		/* xact may use reserved blks */
 {
-	struct xfs_defer_ops	dfops;		/* freed extent records */
 	xfs_mount_t		*mp;		/* mount structure */
 	xfs_trans_t		*tp;		/* transaction pointer */
 	int			blks;		/* space reservation */
@@ -1037,7 +1036,6 @@ xfs_bmap_add_attrfork(
 			rsvd ? XFS_TRANS_RESERVE : 0, &tp);
 	if (error)
 		return error;
-	xfs_defer_init(tp, &dfops);
 
 	xfs_ilock(ip, XFS_ILOCK_EXCL);
 	error = xfs_trans_reserve_quota_nblks(tp, ip, blks, 0, rsvd ?
@@ -1102,7 +1100,7 @@ xfs_bmap_add_attrfork(
 	if (logflags)
 		xfs_trans_log_inode(tp, ip, logflags);
 	if (error)
-		goto bmap_cancel;
+		goto trans_cancel;
 	if (!xfs_sb_version_hasattr(&mp->m_sb) ||
 	   (!xfs_sb_version_hasattr2(&mp->m_sb) && version == 2)) {
 		bool log_sb = false;
@@ -1121,15 +1119,10 @@ xfs_bmap_add_attrfork(
 			xfs_log_sb(tp);
 	}
 
-	error = xfs_defer_finish(&tp, &dfops);
-	if (error)
-		goto bmap_cancel;
 	error = xfs_trans_commit(tp);
 	xfs_iunlock(ip, XFS_ILOCK_EXCL);
 	return error;
 
-bmap_cancel:
-	xfs_defer_cancel(&dfops);
 trans_cancel:
 	xfs_trans_cancel(tp);
 	xfs_iunlock(ip, XFS_ILOCK_EXCL);
@@ -5953,14 +5946,12 @@ xfs_bmap_split_extent(
 {
 	struct xfs_mount        *mp = ip->i_mount;
 	struct xfs_trans        *tp;
-	struct xfs_defer_ops    dfops;
 	int                     error;
 
 	error = xfs_trans_alloc(mp, &M_RES(mp)->tr_write,
 			XFS_DIOSTRAT_SPACE_RES(mp, 0), 0, 0, &tp);
 	if (error)
 		return error;
-	xfs_defer_init(tp, &dfops);
 
 	xfs_ilock(ip, XFS_ILOCK_EXCL);
 	xfs_trans_ijoin(tp, ip, XFS_ILOCK_EXCL);
@@ -5969,14 +5960,9 @@ xfs_bmap_split_extent(
 	if (error)
 		goto out;
 
-	error = xfs_defer_finish(&tp, &dfops);
-	if (error)
-		goto out;
-
 	return xfs_trans_commit(tp);
 
 out:
-	xfs_defer_cancel(&dfops);
 	xfs_trans_cancel(tp);
 	return error;
 }
diff --git a/fs/xfs/libxfs/xfs_refcount.c b/fs/xfs/libxfs/xfs_refcount.c
index 9ef1f440a6f2..4cbc2efb099e 100644
--- a/fs/xfs/libxfs/xfs_refcount.c
+++ b/fs/xfs/libxfs/xfs_refcount.c
@@ -1635,7 +1635,6 @@ xfs_refcount_recover_cow_leftovers(
 	struct list_head		debris;
 	union xfs_btree_irec		low;
 	union xfs_btree_irec		high;
-	struct xfs_defer_ops		dfops;
 	xfs_fsblock_t			fsb;
 	xfs_agblock_t			agbno;
 	int				error;
@@ -1691,22 +1690,17 @@ xfs_refcount_recover_cow_leftovers(
 		trace_xfs_refcount_recover_extent(mp, agno, &rr->rr_rrec);
 
 		/* Free the orphan record */
-		xfs_defer_init(tp, &dfops);
 		agbno = rr->rr_rrec.rc_startblock - XFS_REFC_COW_START;
 		fsb = XFS_AGB_TO_FSB(mp, agno, agbno);
 		error = xfs_refcount_free_cow_extent(mp, tp->t_dfops, fsb,
 				rr->rr_rrec.rc_blockcount);
 		if (error)
-			goto out_defer;
+			goto out_trans;
 
 		/* Free the block. */
 		xfs_bmap_add_free(mp, tp->t_dfops, fsb,
 				rr->rr_rrec.rc_blockcount, NULL);
 
-		error = xfs_defer_finish(&tp, tp->t_dfops);
-		if (error)
-			goto out_defer;
-
 		error = xfs_trans_commit(tp);
 		if (error)
 			goto out_free;
@@ -1716,8 +1710,6 @@ xfs_refcount_recover_cow_leftovers(
 	}
 
 	return error;
-out_defer:
-	xfs_defer_cancel(tp->t_dfops);
 out_trans:
 	xfs_trans_cancel(tp);
 out_free: