From: Jaegeuk Kim <jaegeuk@kernel.org>
Date: Mon, 13 Dec 2021 21:28:40 +0000 (-0800)
Subject: f2fs: avoid down_write on nat_tree_lock during checkpoint
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=0df035c7208c5e3e2ae7685548353ae536a19015;p=linux.git

f2fs: avoid down_write on nat_tree_lock during checkpoint

Let's cache nat entry if there's no lock contention only.

Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
---

diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c
index 556fcd8457f3f..b1bc7d76da3b6 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;