f2fs: try grabbing node page lock aggressively in sync scenario

[ Upstream commit 4b270a8c ]

In synchronous scenario, like in checkpoint(), we are going to flush
dirty node pages to device synchronously, we can easily failed
writebacking node page due to trylock_page() failure, especially in
condition of intensive lock competition, which can cause long latency
of checkpoint(). So let's use lock_page() in synchronous scenario to
avoid this issue.
Signed-off-by: Yunlei He <heyunlei@huawei.com>
Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

fs/f2fs/node.c

@@ -1463,7 +1463,9 @@ int sync_node_pages(struct f2fs_sb_info *sbi, struct writeback_control *wbc)
 						!is_cold_node(page)))
 				continue;
 lock_node:
-			if (!trylock_page(page))
+			if (wbc->sync_mode == WB_SYNC_ALL)
+				lock_page(page);
+			else if (!trylock_page(page))
 				continue;
 
 			if (unlikely(page->mapping != NODE_MAPPING(sbi))) {