xfs: simplify inode reclaim tagging interfaces

Inode radix tree tagging for reclaim passes a lot of unnecessary
variables around. Over time the xfs-perag has grown a xfs_mount
backpointer, and an internal agno so we don't need to pass other
variables into the tagging functions to supply this information.

Rework the functions to pass the minimal variable set required
and simplify the internal logic and flow.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>

fs/xfs/xfs_icache.c

@@ -37,8 +37,7 @@
 #include <linux/kthread.h>
 #include <linux/freezer.h>
 
-STATIC void __xfs_inode_clear_reclaim_tag(struct xfs_mount *mp,
-				struct xfs_perag *pag, struct xfs_inode *ip);
+STATIC void xfs_inode_clear_reclaim_tag(struct xfs_perag *pag, xfs_ino_t ino);
 
 /*
  * Allocate and initialise an xfs_inode.
@@ -271,7 +270,7 @@ xfs_iget_cache_hit(
 		 */
 		ip->i_flags &= ~XFS_IRECLAIM_RESET_FLAGS;
 		ip->i_flags |= XFS_INEW;
-		__xfs_inode_clear_reclaim_tag(mp, pag, ip);
+		xfs_inode_clear_reclaim_tag(pag, ip->i_ino);
 		inode->i_state = I_NEW;
 
 		ASSERT(!rwsem_is_locked(&ip->i_iolock.mr_lock));
@@ -768,78 +767,81 @@ xfs_reclaim_worker(
 }
 
 static void
-__xfs_inode_set_reclaim_tag(
-	struct xfs_perag	*pag,
-	struct xfs_inode	*ip)
+xfs_perag_set_reclaim_tag(
+	struct xfs_perag	*pag)
 {
-	radix_tree_tag_set(&pag->pag_ici_root,
-			   XFS_INO_TO_AGINO(ip->i_mount, ip->i_ino),
+	struct xfs_mount	*mp = pag->pag_mount;
+
+	ASSERT(spin_is_locked(&pag->pag_ici_lock));
+	if (pag->pag_ici_reclaimable++)
+		return;
+
+	/* propagate the reclaim tag up into the perag radix tree */
+	spin_lock(&mp->m_perag_lock);
+	radix_tree_tag_set(&mp->m_perag_tree, pag->pag_agno,
 			   XFS_ICI_RECLAIM_TAG);
+	spin_unlock(&mp->m_perag_lock);
 
-	if (!pag->pag_ici_reclaimable) {
-		/* propagate the reclaim tag up into the perag radix tree */
-		spin_lock(&ip->i_mount->m_perag_lock);
-		radix_tree_tag_set(&ip->i_mount->m_perag_tree, pag->pag_agno,
-				XFS_ICI_RECLAIM_TAG);
-		spin_unlock(&ip->i_mount->m_perag_lock);
+	/* schedule periodic background inode reclaim */
+	xfs_reclaim_work_queue(mp);
 
-		/* schedule periodic background inode reclaim */
-		xfs_reclaim_work_queue(ip->i_mount);
+	trace_xfs_perag_set_reclaim(mp, pag->pag_agno, -1, _RET_IP_);
+}
 
-		trace_xfs_perag_set_reclaim(ip->i_mount, pag->pag_agno,
-							-1, _RET_IP_);
-	}
-	pag->pag_ici_reclaimable++;
+static void
+xfs_perag_clear_reclaim_tag(
+	struct xfs_perag	*pag)
+{
+	struct xfs_mount	*mp = pag->pag_mount;
+
+	ASSERT(spin_is_locked(&pag->pag_ici_lock));
+	if (--pag->pag_ici_reclaimable)
+		return;
+
+	/* clear the reclaim tag from the perag radix tree */
+	spin_lock(&mp->m_perag_lock);
+	radix_tree_tag_clear(&mp->m_perag_tree, pag->pag_agno,
+			     XFS_ICI_RECLAIM_TAG);
+	spin_unlock(&mp->m_perag_lock);
+	trace_xfs_perag_clear_reclaim(mp, pag->pag_agno, -1, _RET_IP_);
 }
 
+
 /*
  * We set the inode flag atomically with the radix tree tag.
  * Once we get tag lookups on the radix tree, this inode flag
  * can go away.
  */
 void
 xfs_inode_set_reclaim_tag(
-	xfs_inode_t	*ip)
+	struct xfs_inode	*ip)
 {
-	struct xfs_mount *mp = ip->i_mount;
-	struct xfs_perag *pag;
+	struct xfs_mount	*mp = ip->i_mount;
+	struct xfs_perag	*pag;
 
 	pag = xfs_perag_get(mp, XFS_INO_TO_AGNO(mp, ip->i_ino));
 	spin_lock(&pag->pag_ici_lock);
 	spin_lock(&ip->i_flags_lock);
-	__xfs_inode_set_reclaim_tag(pag, ip);
+
+	radix_tree_tag_set(&pag->pag_ici_root, XFS_INO_TO_AGINO(mp, ip->i_ino),
+			   XFS_ICI_RECLAIM_TAG);
+	xfs_perag_set_reclaim_tag(pag);
 	__xfs_iflags_set(ip, XFS_IRECLAIMABLE);
+
 	spin_unlock(&ip->i_flags_lock);
 	spin_unlock(&pag->pag_ici_lock);
 	xfs_perag_put(pag);
 }
 
 STATIC void
-__xfs_inode_clear_reclaim(
-	xfs_perag_t	*pag,
-	xfs_inode_t	*ip)
-{
-	pag->pag_ici_reclaimable--;
-	if (!pag->pag_ici_reclaimable) {
-		/* clear the reclaim tag from the perag radix tree */
-		spin_lock(&ip->i_mount->m_perag_lock);
-		radix_tree_tag_clear(&ip->i_mount->m_perag_tree, pag->pag_agno,
-				XFS_ICI_RECLAIM_TAG);
-		spin_unlock(&ip->i_mount->m_perag_lock);
-		trace_xfs_perag_clear_reclaim(ip->i_mount, pag->pag_agno,
-							-1, _RET_IP_);
-	}
-}
-
-STATIC void
-__xfs_inode_clear_reclaim_tag(
-	xfs_mount_t	*mp,
-	xfs_perag_t	*pag,
-	xfs_inode_t	*ip)
+xfs_inode_clear_reclaim_tag(
+	struct xfs_perag	*pag,
+	xfs_ino_t		ino)
 {
 	radix_tree_tag_clear(&pag->pag_ici_root,
-			XFS_INO_TO_AGINO(mp, ip->i_ino), XFS_ICI_RECLAIM_TAG);
-	__xfs_inode_clear_reclaim(pag, ip);
+			     XFS_INO_TO_AGINO(pag->pag_mount, ino),
+			     XFS_ICI_RECLAIM_TAG);
+	xfs_perag_clear_reclaim_tag(pag);
 }
 
 /*
@@ -1030,7 +1032,7 @@ xfs_reclaim_inode(
 	if (!radix_tree_delete(&pag->pag_ici_root,
 				XFS_INO_TO_AGINO(ip->i_mount, ino)))
 		ASSERT(0);
-	__xfs_inode_clear_reclaim(pag, ip);
+	xfs_perag_clear_reclaim_tag(pag);
 	spin_unlock(&pag->pag_ici_lock);
 
 	/*