f2fs: don't interrupt free nids building during nid allocation

Let build_free_nids support sync/async methods, in allocation flow of nids,
we use synchronuous method, so that we can avoid looping in alloc_nid when
free memory is low; in unblock_operations and f2fs_balance_fs_bg we use
asynchronuous method in where low memory condition can interrupt us.

Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

1 files changed, 10 insertions, 12 deletions

diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c
index f21e5bba9483..b6894ef3d907 100644
--- a/fs/f2fs/node.c
+++ b/fs/f2fs/node.c
@@ -1733,9 +1733,6 @@ static int add_free_nid(struct f2fs_sb_info *sbi, nid_t nid, bool build)
 	struct nat_entry *ne;
 	int err;
 
-	if (!available_free_memory(sbi, FREE_NIDS))
-		return -1;
-
 	/* 0 nid should not be used */
 	if (unlikely(nid == 0))
 		return 0;
@@ -1803,14 +1800,12 @@ static void scan_nat_page(struct f2fs_sb_info *sbi,
 
 		blk_addr = le32_to_cpu(nat_blk->entries[i].block_addr);
 		f2fs_bug_on(sbi, blk_addr == NEW_ADDR);
-		if (blk_addr == NULL_ADDR) {
-			if (add_free_nid(sbi, start_nid, true) < 0)
-				break;
-		}
+		if (blk_addr == NULL_ADDR)
+			add_free_nid(sbi, start_nid, true);
 	}
 }
 
-void __build_free_nids(struct f2fs_sb_info *sbi)
+void __build_free_nids(struct f2fs_sb_info *sbi, bool sync)
 {
 	struct f2fs_nm_info *nm_i = NM_I(sbi);
 	struct curseg_info *curseg = CURSEG_I(sbi, CURSEG_HOT_DATA);
@@ -1822,6 +1817,9 @@ void __build_free_nids(struct f2fs_sb_info *sbi)
 	if (nm_i->nid_cnt[FREE_NID_LIST] >= NAT_ENTRY_PER_BLOCK)
 		return;
 
+	if (!sync && !available_free_memory(sbi, FREE_NIDS))
+		return;
+
 	/* readahead nat pages to be scanned */
 	ra_meta_pages(sbi, NAT_BLOCK_OFFSET(nid), FREE_NID_PAGES,
 							META_NAT, true);
@@ -1864,10 +1862,10 @@ void __build_free_nids(struct f2fs_sb_info *sbi)
 					nm_i->ra_nid_pages, META_NAT, false);
 }
 
-void build_free_nids(struct f2fs_sb_info *sbi)
+void build_free_nids(struct f2fs_sb_info *sbi, bool sync)
 {
 	mutex_lock(&NM_I(sbi)->build_lock);
-	__build_free_nids(sbi);
+	__build_free_nids(sbi, sync);
 	mutex_unlock(&NM_I(sbi)->build_lock);
 }
 
@@ -1906,7 +1904,7 @@ retry:
 	spin_unlock(&nm_i->nid_list_lock);
 
 	/* Let's scan nat pages and its caches to get free nids */
-	build_free_nids(sbi);
+	build_free_nids(sbi, true);
 	goto retry;
 }
 
@@ -2343,7 +2341,7 @@ int build_node_manager(struct f2fs_sb_info *sbi)
 	if (err)
 		return err;
 
-	build_free_nids(sbi);
+	build_free_nids(sbi, true);
 	return 0;
 }