1 files changed, 37 insertions, 15 deletions

diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index c76537a6826a..672d176524f5 100644
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -609,6 +609,24 @@ out_free:
 	kfree(isw);
 }
 
+static bool isw_prepare_wbs_switch(struct inode_switch_wbs_context *isw,
+				   struct list_head *list, int *nr)
+{
+	struct inode *inode;
+
+	list_for_each_entry(inode, list, i_io_list) {
+		if (!inode_prepare_wbs_switch(inode, isw->new_wb))
+			continue;
+
+		isw->inodes[*nr] = inode;
+		(*nr)++;
+
+		if (*nr >= WB_MAX_INODES_PER_ISW - 1)
+			return true;
+	}
+	return false;
+}
+
 /**
  * cleanup_offline_cgwb - detach associated inodes
  * @wb: target wb
@@ -621,7 +639,6 @@ bool cleanup_offline_cgwb(struct bdi_writeback *wb)
 {
 	struct cgroup_subsys_state *memcg_css;
 	struct inode_switch_wbs_context *isw;
-	struct inode *inode;
 	int nr;
 	bool restart = false;
 
@@ -643,17 +660,17 @@ bool cleanup_offline_cgwb(struct bdi_writeback *wb)
 
 	nr = 0;
 	spin_lock(&wb->list_lock);
-	list_for_each_entry(inode, &wb->b_attached, i_io_list) {
-		if (!inode_prepare_wbs_switch(inode, isw->new_wb))
-			continue;
-
-		isw->inodes[nr++] = inode;
-
-		if (nr >= WB_MAX_INODES_PER_ISW - 1) {
-			restart = true;
-			break;
-		}
-	}
+	/*
+	 * In addition to the inodes that have completed writeback, also switch
+	 * cgwbs for those inodes only with dirty timestamps. Otherwise, those
+	 * inodes won't be written back for a long time when lazytime is
+	 * enabled, and thus pinning the dying cgwbs. It won't break the
+	 * bandwidth restrictions, as writeback of inode metadata is not
+	 * accounted for.
+	 */
+	restart = isw_prepare_wbs_switch(isw, &wb->b_attached, &nr);
+	if (!restart)
+		restart = isw_prepare_wbs_switch(isw, &wb->b_dirty_time, &nr);
 	spin_unlock(&wb->list_lock);
 
 	/* no attached inodes? bail out */
@@ -1557,10 +1574,15 @@ static void requeue_inode(struct inode *inode, struct bdi_writeback *wb,
 
 	if (wbc->pages_skipped) {
 		/*
-		 * writeback is not making progress due to locked
-		 * buffers. Skip this inode for now.
+		 * Writeback is not making progress due to locked buffers.
+		 * Skip this inode for now. Although having skipped pages
+		 * is odd for clean inodes, it can happen for some
+		 * filesystems so handle that gracefully.
 		 */
-		redirty_tail_locked(inode, wb);
+		if (inode->i_state & I_DIRTY_ALL)
+			redirty_tail_locked(inode, wb);
+		else
+			inode_cgwb_move_to_attached(inode, wb);
 		return;
 	}