From 4c935a2fd73c06d5eb8d65bc9fec4993ba57336b Mon Sep 17 00:00:00 2001
From: Cliff Chen <cliff.chen@rock-chips.com>
Date: Thu, 16 Apr 2020 11:45:23 +0800
Subject: [PATCH] f2fs: Fix recovery is too slow when power fail on much fsync

By default fsync option, if fsync is called frequently, and suddenly
lost power, the POR will consume too much memory at mounting, this
process may be very slow due to a large number of swapping.

Change-Id: I8235098cca062d7ab58af4ebed414aed9aba6c75
Signed-off-by: Cliff Chen <cliff.chen@rock-chips.com>
Signed-off-by: Alex Wang <alex.wang@rock-chips.com>
---
 fs/f2fs/f2fs.h  |  2 ++
 fs/f2fs/file.c  | 23 ++++++++++++++++++++++-
 fs/f2fs/super.c |  3 +++
 3 files changed, 27 insertions(+), 1 deletion(-)

diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 307893ca1bdc..9f6a028deec7 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -1452,6 +1452,8 @@ struct f2fs_sb_info {
 	/* migration granularity of garbage collection, unit: segment */
 	unsigned int migration_granularity;
 
+	atomic_t no_cp_fsync_pages;
+
 	/*
 	 * for stat information.
 	 * one is for the LFS mode, and the other is for the SSR mode.
diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
index 479d95b7e7b9..cda48a564ffa 100644
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -227,6 +227,25 @@ static void try_to_fix_pino(struct inode *inode)
 	up_write(&fi->i_sem);
 }
 
+static bool f2fs_update_fsync_count(struct f2fs_sb_info *sbi,
+					unsigned int npages)
+{
+	struct sysinfo val;
+	unsigned long avail_ram;
+
+	si_meminfo(&val);
+
+	/* only uses low memory */
+	avail_ram = val.totalram - val.totalhigh;
+	avail_ram = (avail_ram * DEF_RAM_THRESHOLD) / 100;
+
+	if ((atomic_read(&sbi->no_cp_fsync_pages) + npages) > avail_ram)
+		return false;
+
+	atomic_add(npages, &sbi->no_cp_fsync_pages);
+	return true;
+}
+
 static int f2fs_do_sync_file(struct file *file, loff_t start, loff_t end,
 						int datasync, bool atomic)
 {
@@ -234,6 +253,7 @@ static int f2fs_do_sync_file(struct file *file, loff_t start, loff_t end,
 	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
 	nid_t ino = inode->i_ino;
 	int ret = 0;
+	unsigned int npages = 0;
 	enum cp_reason_type cp_reason = 0;
 	struct writeback_control wbc = {
 		.sync_mode = WB_SYNC_ALL,
@@ -261,6 +281,7 @@ static int f2fs_do_sync_file(struct file *file, loff_t start, loff_t end,
 		goto go_write;
 
 	/* if fdatasync is triggered, let's do in-place-update */
+	npages = get_dirty_pages(inode);
 	if (datasync || get_dirty_pages(inode) <= SM_I(sbi)->min_fsync_blocks)
 		set_inode_flag(inode, FI_NEED_IPU);
 	ret = file_write_and_wait_range(file, start, end);
@@ -301,7 +322,7 @@ go_write:
 	cp_reason = need_do_checkpoint(inode);
 	up_read(&F2FS_I(inode)->i_sem);
 
-	if (cp_reason) {
+	if (cp_reason || !f2fs_update_fsync_count(sbi, npages)) {
 		/* all the dirty node pages should be flushed for POR */
 		ret = f2fs_sync_fs(inode->i_sb, 1);
 
diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index 07a7e3ff4600..896c30e7c48d 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -1256,6 +1256,7 @@ int f2fs_sync_fs(struct super_block *sb, int sync)
 
 		cpc.reason = __get_cp_reason(sbi);
 
+		atomic_set(&sbi->no_cp_fsync_pages, 0);
 		down_write(&sbi->gc_lock);
 		err = f2fs_write_checkpoint(sbi, &cpc);
 		up_write(&sbi->gc_lock);
@@ -3610,6 +3611,8 @@ try_onemore:
 
 	f2fs_build_gc_manager(sbi);
 
+	atomic_set(&sbi->no_cp_fsync_pages, 0);
+
 	err = f2fs_build_stats(sbi);
 	if (err)
 		goto free_nm;