f2fs: drop page cache after fs shutdown

Don't remain dirtied page cache in f2fs after shutdown, it can mitigate
memory pressure of whole system, in order to keep other modules working
properly.
Signed-off-by: NChao Yu <yuchao0@huawei.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

fs/f2fs/checkpoint.c

@@ -237,12 +237,15 @@ static int __f2fs_write_meta_page(struct page *page,
 
 	trace_f2fs_writepage(page, META);
 
+	if (unlikely(f2fs_cp_error(sbi))) {
+		dec_page_count(sbi, F2FS_DIRTY_META);
+		unlock_page(page);
+		return 0;
+	}
 	if (unlikely(is_sbi_flag_set(sbi, SBI_POR_DOING)))
 		goto redirty_out;
 	if (wbc->for_reclaim && page->index < GET_SUM_BLOCK(sbi, 0))
 		goto redirty_out;
-	if (unlikely(f2fs_cp_error(sbi)))
-		goto redirty_out;
 
 	write_meta_page(sbi, page, io_type);
 	dec_page_count(sbi, F2FS_DIRTY_META);

fs/f2fs/data.c

@@ -1716,6 +1716,12 @@ static int __write_data_page(struct page *page, bool *submitted,
 
 	trace_f2fs_writepage(page, DATA);
 
+	/* we should bypass data pages to proceed the kworkder jobs */
+	if (unlikely(f2fs_cp_error(sbi))) {
+		mapping_set_error(page->mapping, -EIO);
+		goto out;
+	}
+
 	if (unlikely(is_sbi_flag_set(sbi, SBI_POR_DOING)))
 		goto redirty_out;
 
@@ -1740,12 +1746,6 @@ static int __write_data_page(struct page *page, bool *submitted,
 			available_free_memory(sbi, BASE_CHECK))))
 		goto redirty_out;
 
-	/* we should bypass data pages to proceed the kworkder jobs */
-	if (unlikely(f2fs_cp_error(sbi))) {
-		mapping_set_error(page->mapping, -EIO);
-		goto out;
-	}
-
 	/* Dentry blocks are controlled by checkpoint */
 	if (S_ISDIR(inode->i_mode)) {
 		fio.need_lock = LOCK_DONE;

fs/f2fs/node.c

@@ -1340,10 +1340,14 @@ static int __write_node_page(struct page *page, bool atomic, bool *submitted,
 
 	trace_f2fs_writepage(page, NODE);
 
+	if (unlikely(f2fs_cp_error(sbi))) {
+		dec_page_count(sbi, F2FS_DIRTY_NODES);
+		unlock_page(page);
+		return 0;
+	}
+
 	if (unlikely(is_sbi_flag_set(sbi, SBI_POR_DOING)))
 		goto redirty_out;
-	if (unlikely(f2fs_cp_error(sbi)))
-		goto redirty_out;
 
 	/* get old block addr of this node page */
 	nid = nid_of_node(page);
@@ -1580,12 +1584,6 @@ int sync_node_pages(struct f2fs_sb_info *sbi, struct writeback_control *wbc,
 			struct page *page = pvec.pages[i];
 			bool submitted = false;
 
-			if (unlikely(f2fs_cp_error(sbi))) {
-				pagevec_release(&pvec);
-				ret = -EIO;
-				goto out;
-			}
-
 			/*
 			 * flushing sequence with step:
 			 * 0. indirect nodes
@@ -1655,9 +1653,12 @@ int sync_node_pages(struct f2fs_sb_info *sbi, struct writeback_control *wbc,
 		step++;
 		goto next_step;
 	}
-out:
+
 	if (nwritten)
 		f2fs_submit_merged_write(sbi, NODE);
+
+	if (unlikely(f2fs_cp_error(sbi)))
+		return -EIO;
 	return ret;
 }