1 files changed, 14 insertions, 9 deletions

diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c
index 219506ca9a97..50b2874e758c 100644
--- a/fs/f2fs/node.c
+++ b/fs/f2fs/node.c
@@ -430,6 +430,10 @@ static void cache_nat_entry(struct f2fs_sb_info *sbi, nid_t nid,
 	struct f2fs_nm_info *nm_i = NM_I(sbi);
 	struct nat_entry *new, *e;
 
+	/* Let's mitigate lock contention of nat_tree_lock during checkpoint */
+	if (rwsem_is_locked(&sbi->cp_global_sem))
+		return;
+
 	new = __alloc_nat_entry(sbi, nid, false);
 	if (!new)
 		return;
@@ -539,7 +543,7 @@ int f2fs_try_to_free_nats(struct f2fs_sb_info *sbi, int nr_shrink)
 }
 
 int f2fs_get_node_info(struct f2fs_sb_info *sbi, nid_t nid,
-						struct node_info *ni)
+				struct node_info *ni, bool checkpoint_context)
 {
 	struct f2fs_nm_info *nm_i = NM_I(sbi);
 	struct curseg_info *curseg = CURSEG_I(sbi, CURSEG_HOT_DATA);
@@ -572,9 +576,10 @@ retry:
 	 * nat_tree_lock. Therefore, we should retry, if we failed to grab here
 	 * while not bothering checkpoint.
 	 */
-	if (!rwsem_is_locked(&sbi->cp_global_sem)) {
+	if (!rwsem_is_locked(&sbi->cp_global_sem) || checkpoint_context) {
 		down_read(&curseg->journal_rwsem);
-	} else if (!down_read_trylock(&curseg->journal_rwsem)) {
+	} else if (rwsem_is_contended(&nm_i->nat_tree_lock) ||
+				!down_read_trylock(&curseg->journal_rwsem)) {
 		up_read(&nm_i->nat_tree_lock);
 		goto retry;
 	}
@@ -887,7 +892,7 @@ static int truncate_node(struct dnode_of_data *dn)
 	int err;
 	pgoff_t index;
 
-	err = f2fs_get_node_info(sbi, dn->nid, &ni);
+	err = f2fs_get_node_info(sbi, dn->nid, &ni, false);
 	if (err)
 		return err;
 
@@ -1286,7 +1291,7 @@ struct page *f2fs_new_node_page(struct dnode_of_data *dn, unsigned int ofs)
 		goto fail;
 
 #ifdef CONFIG_F2FS_CHECK_FS
-	err = f2fs_get_node_info(sbi, dn->nid, &new_ni);
+	err = f2fs_get_node_info(sbi, dn->nid, &new_ni, false);
 	if (err) {
 		dec_valid_node_count(sbi, dn->inode, !ofs);
 		goto fail;
@@ -1348,7 +1353,7 @@ static int read_node_page(struct page *page, int op_flags)
 		return LOCKED_PAGE;
 	}
 
-	err = f2fs_get_node_info(sbi, page->index, &ni);
+	err = f2fs_get_node_info(sbi, page->index, &ni, false);
 	if (err)
 		return err;
 
@@ -1600,7 +1605,7 @@ static int __write_node_page(struct page *page, bool atomic, bool *submitted,
 	nid = nid_of_node(page);
 	f2fs_bug_on(sbi, page->index != nid);
 
-	if (f2fs_get_node_info(sbi, nid, &ni))
+	if (f2fs_get_node_info(sbi, nid, &ni, !do_balance))
 		goto redirty_out;
 
 	if (wbc->for_reclaim) {
@@ -2701,7 +2706,7 @@ int f2fs_recover_xattr_data(struct inode *inode, struct page *page)
 		goto recover_xnid;
 
 	/* 1: invalidate the previous xattr nid */
-	err = f2fs_get_node_info(sbi, prev_xnid, &ni);
+	err = f2fs_get_node_info(sbi, prev_xnid, &ni, false);
 	if (err)
 		return err;
 
@@ -2741,7 +2746,7 @@ int f2fs_recover_inode_page(struct f2fs_sb_info *sbi, struct page *page)
 	struct page *ipage;
 	int err;
 
-	err = f2fs_get_node_info(sbi, ino, &old_ni);
+	err = f2fs_get_node_info(sbi, ino, &old_ni, false);
 	if (err)
 		return err;