xfs: introduce xfs_dialloc_roll()

Introduce a helper to make the on-disk inode allocation rolling
logic clearer in preparation of the following cleanup.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Gao Xiang <hsiangkao@redhat.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>

fs/xfs/libxfs/xfs_ialloc.c

@@ -1682,6 +1682,41 @@ xfs_dialloc_ag(
 	return error;
 }
 
+int
+xfs_dialloc_roll(
+	struct xfs_trans	**tpp,
+	struct xfs_buf		*agibp)
+{
+	struct xfs_trans	*tp = *tpp;
+	struct xfs_dquot_acct	*dqinfo;
+	int			error;
+
+	/*
+	 * Hold to on to the agibp across the commit so no other allocation can
+	 * come in and take the free inodes we just allocated for our caller.
+	 */
+	xfs_trans_bhold(tp, agibp);
+
+	/*
+	 * We want the quota changes to be associated with the next transaction,
+	 * NOT this one. So, detach the dqinfo from this and attach it to the
+	 * next transaction.
+	 */
+	dqinfo = tp->t_dqinfo;
+	tp->t_dqinfo = NULL;
+
+	error = xfs_trans_roll(&tp);
+
+	/* Re-attach the quota info that we detached from prev trx. */
+	tp->t_dqinfo = dqinfo;
+
+	*tpp = tp;
+	if (error)
+		return error;
+	xfs_trans_bjoin(tp, agibp);
+	return 0;
+}
+
 /*
  * Allocate an inode on disk.
  *

fs/xfs/libxfs/xfs_ialloc.h

@@ -32,6 +32,11 @@ xfs_make_iptr(struct xfs_mount *mp, struct xfs_buf *b, int o)
 	return xfs_buf_offset(b, o << (mp)->m_sb.sb_inodelog);
 }
 
+int
+xfs_dialloc_roll(
+	struct xfs_trans	**tpp,
+	struct xfs_buf		*agibp);
+
 /*
  * Allocate an inode on disk.
  * Mode is used to tell whether the new inode will need space, and whether

fs/xfs/xfs_inode.c

@@ -958,7 +958,6 @@ xfs_dir_ialloc(
 	xfs_inode_t	*ip;
 	xfs_buf_t	*ialloc_context = NULL;
 	int		code;
-	void		*dqinfo;
 
 	tp = *tpp;
 	ASSERT(tp->t_flags & XFS_TRANS_PERM_LOG_RES);
@@ -1002,41 +1001,13 @@ xfs_dir_ialloc(
 	 * to succeed the second time.
 	 */
 	if (ialloc_context) {
-		/*
-		 * Normally, xfs_trans_commit releases all the locks.
-		 * We call bhold to hang on to the ialloc_context across
-		 * the commit.  Holding this buffer prevents any other
-		 * processes from doing any allocations in this
-		 * allocation group.
-		 */
-		xfs_trans_bhold(tp, ialloc_context);
-
-		/*
-		 * We want the quota changes to be associated with the next
-		 * transaction, NOT this one. So, detach the dqinfo from this
-		 * and attach it to the next transaction.
-		 */
-		dqinfo = NULL;
-		if (tp->t_dqinfo) {
-			dqinfo = (void *)tp->t_dqinfo;
-			tp->t_dqinfo = NULL;
-		}
-
-		code = xfs_trans_roll(&tp);
-
-		/*
-		 * Re-attach the quota info that we detached from prev trx.
-		 */
-		if (dqinfo)
-			tp->t_dqinfo = dqinfo;
-
+		code = xfs_dialloc_roll(&tp, ialloc_context);
 		if (code) {
 			xfs_buf_relse(ialloc_context);
 			*tpp = tp;
 			*ipp = NULL;
 			return code;
 		}
-		xfs_trans_bjoin(tp, ialloc_context);
 
 		/*
 		 * Call ialloc again. Since we've locked out all