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>

1 files changed, 8 insertions, 30 deletions

diff --git a/fs/xfs/xfs_symlink.c b/fs/xfs/xfs_symlink.c
index d1ab0afa2723..ce801aedbcdc 100644
--- a/fs/xfs/xfs_symlink.c
+++ b/fs/xfs/xfs_symlink.c
@@ -163,7 +163,6 @@ xfs_symlink(
 	struct xfs_inode	*ip = NULL;
 	int			error = 0;
 	int			pathlen;
-	struct xfs_defer_ops	dfops;
 	bool                    unlock_dp_on_error = false;
 	xfs_fileoff_t		first_fsb;
 	xfs_filblks_t		fs_blocks;
@@ -242,12 +241,6 @@ xfs_symlink(
 		goto out_trans_cancel;
 
 	/*
-	 * Initialize the bmap freelist prior to calling either
-	 * bmapi or the directory create code.
-	 */
-	xfs_defer_init(tp, &dfops);
-
-	/*
 	 * Allocate an inode for the symlink.
 	 */
 	error = xfs_dir_ialloc(&tp, dp, S_IFLNK | (mode & ~S_IFMT), 1, 0,
@@ -290,7 +283,7 @@ xfs_symlink(
 		error = xfs_bmapi_write(tp, ip, first_fsb, fs_blocks,
 				  XFS_BMAPI_METADATA, resblks, mval, &nmaps);
 		if (error)
-			goto out_bmap_cancel;
+			goto out_trans_cancel;
 
 		if (resblks)
 			resblks -= fs_blocks;
@@ -308,7 +301,7 @@ xfs_symlink(
 					       BTOBB(byte_cnt), 0);
 			if (!bp) {
 				error = -ENOMEM;
-				goto out_bmap_cancel;
+				goto out_trans_cancel;
 			}
 			bp->b_ops = &xfs_symlink_buf_ops;
 
@@ -337,7 +330,7 @@ xfs_symlink(
 	 */
 	error = xfs_dir_createname(tp, dp, link_name, ip->i_ino, resblks);
 	if (error)
-		goto out_bmap_cancel;
+		goto out_trans_cancel;
 	xfs_trans_ichgtime(tp, dp, XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG);
 	xfs_trans_log_inode(tp, dp, XFS_ILOG_CORE);
 
@@ -350,10 +343,6 @@ xfs_symlink(
 		xfs_trans_set_sync(tp);
 	}
 
-	error = xfs_defer_finish(&tp, tp->t_dfops);
-	if (error)
-		goto out_bmap_cancel;
-
 	error = xfs_trans_commit(tp);
 	if (error)
 		goto out_release_inode;
@@ -365,8 +354,6 @@ xfs_symlink(
 	*ipp = ip;
 	return 0;
 
-out_bmap_cancel:
-	xfs_defer_cancel(tp->t_dfops);
 out_trans_cancel:
 	xfs_trans_cancel(tp);
 out_release_inode:
@@ -399,7 +386,6 @@ xfs_inactive_symlink_rmt(
 	xfs_buf_t	*bp;
 	int		done;
 	int		error;
-	struct xfs_defer_ops	dfops;
 	int		i;
 	xfs_mount_t	*mp;
 	xfs_bmbt_irec_t	mval[XFS_SYMLINK_MAPS];
@@ -438,7 +424,6 @@ xfs_inactive_symlink_rmt(
 	 * Find the block(s) so we can inval and unmap them.
 	 */
 	done = 0;
-	xfs_defer_init(tp, &dfops);
 	nmaps = ARRAY_SIZE(mval);
 	error = xfs_bmapi_read(ip, 0, xfs_symlink_blocks(mp, size),
 				mval, &nmaps, 0);
@@ -453,7 +438,7 @@ xfs_inactive_symlink_rmt(
 			XFS_FSB_TO_BB(mp, mval[i].br_blockcount), 0);
 		if (!bp) {
 			error = -ENOMEM;
-			goto error_bmap_cancel;
+			goto error_trans_cancel;
 		}
 		xfs_trans_binval(tp, bp);
 	}
@@ -462,19 +447,14 @@ xfs_inactive_symlink_rmt(
 	 */
 	error = xfs_bunmapi(tp, ip, 0, size, 0, nmaps, &done);
 	if (error)
-		goto error_bmap_cancel;
+		goto error_trans_cancel;
 	ASSERT(done);
-	/*
-	 * Commit the first transaction.  This logs the EFI and the inode.
-	 */
-	xfs_defer_ijoin(tp->t_dfops, ip);
-	error = xfs_defer_finish(&tp, tp->t_dfops);
-	if (error)
-		goto error_bmap_cancel;
 
 	/*
-	 * Commit the transaction containing extent freeing and EFDs.
+	 * Commit the transaction. This first logs the EFI and the inode, then
+	 * rolls and commits the transaction that frees the extents.
 	 */
+	xfs_defer_ijoin(tp->t_dfops, ip);
 	xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
 	error = xfs_trans_commit(tp);
 	if (error) {
@@ -492,8 +472,6 @@ xfs_inactive_symlink_rmt(
 	xfs_iunlock(ip, XFS_ILOCK_EXCL);
 	return 0;
 
-error_bmap_cancel:
-	xfs_defer_cancel(tp->t_dfops);
 error_trans_cancel:
 	xfs_trans_cancel(tp);
 error_unlock: