f2fs: don't trigger data flush in foreground operation
Data flush can generate heavy IO and cause long latency during
flush, so it's not appropriate to trigger it in foreground
operation.
And also, we may face below potential deadlock during data flush:
- f2fs_write_multi_pages
- f2fs_write_raw_pages
- f2fs_write_single_data_page
- f2fs_balance_fs
- f2fs_balance_fs_bg
- f2fs_sync_dirty_inodes
- filemap_fdatawrite -- stuck on flush same cluster
Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index 601d67e..aece09a 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -496,7 +496,7 @@ void f2fs_balance_fs(struct f2fs_sb_info *sbi, bool need)
/* balance_fs_bg is able to be pending */
if (need && excess_cached_nats(sbi))
- f2fs_balance_fs_bg(sbi);
+ f2fs_balance_fs_bg(sbi, false);
if (!f2fs_is_checkpoint_ready(sbi))
return;
@@ -511,7 +511,7 @@ void f2fs_balance_fs(struct f2fs_sb_info *sbi, bool need)
}
}
-void f2fs_balance_fs_bg(struct f2fs_sb_info *sbi)
+void f2fs_balance_fs_bg(struct f2fs_sb_info *sbi, bool from_bg)
{
if (unlikely(is_sbi_flag_set(sbi, SBI_POR_DOING)))
return;
@@ -540,7 +540,7 @@ void f2fs_balance_fs_bg(struct f2fs_sb_info *sbi)
excess_dirty_nats(sbi) ||
excess_dirty_nodes(sbi) ||
f2fs_time_over(sbi, CP_TIME)) {
- if (test_opt(sbi, DATA_FLUSH)) {
+ if (test_opt(sbi, DATA_FLUSH) && from_bg) {
struct blk_plug plug;
mutex_lock(&sbi->flush_lock);