1 files changed, 28 insertions, 4 deletions

diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index c756923a7302..b2b18637cb9e 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -514,7 +514,7 @@ static int f2fs_show_options(struct seq_file *seq, struct dentry *root)
 {
 	struct f2fs_sb_info *sbi = F2FS_SB(root->d_sb);
 
-	if (!(root->d_sb->s_flags & MS_RDONLY) && test_opt(sbi, BG_GC))
+	if (!f2fs_readonly(sbi->sb) && test_opt(sbi, BG_GC))
 		seq_printf(seq, ",background_gc=%s", "on");
 	else
 		seq_printf(seq, ",background_gc=%s", "off");
@@ -542,7 +542,7 @@ static int f2fs_show_options(struct seq_file *seq, struct dentry *root)
 		seq_puts(seq, ",disable_ext_identify");
 	if (test_opt(sbi, INLINE_DATA))
 		seq_puts(seq, ",inline_data");
-	if (test_opt(sbi, FLUSH_MERGE))
+	if (!f2fs_readonly(sbi->sb) && test_opt(sbi, FLUSH_MERGE))
 		seq_puts(seq, ",flush_merge");
 	seq_printf(seq, ",active_logs=%u", sbi->active_logs);
 
@@ -594,6 +594,8 @@ static int f2fs_remount(struct super_block *sb, int *flags, char *data)
 	struct f2fs_sb_info *sbi = F2FS_SB(sb);
 	struct f2fs_mount_info org_mount_opt;
 	int err, active_logs;
+	bool need_restart_gc = false;
+	bool need_stop_gc = false;
 
 	sync_filesystem(sb);
 
@@ -611,7 +613,7 @@ static int f2fs_remount(struct super_block *sb, int *flags, char *data)
 
 	/*
 	 * Previous and new state of filesystem is RO,
-	 * so no point in checking GC conditions.
+	 * so skip checking GC and FLUSH_MERGE conditions.
 	 */
 	if ((sb->s_flags & MS_RDONLY) && (*flags & MS_RDONLY))
 		goto skip;
@@ -625,18 +627,40 @@ static int f2fs_remount(struct super_block *sb, int *flags, char *data)
 		if (sbi->gc_thread) {
 			stop_gc_thread(sbi);
 			f2fs_sync_fs(sb, 1);
+			need_restart_gc = true;
 		}
 	} else if (test_opt(sbi, BG_GC) && !sbi->gc_thread) {
 		err = start_gc_thread(sbi);
 		if (err)
 			goto restore_opts;
+		need_stop_gc = true;
+	}
+
+	/*
+	 * We stop issue flush thread if FS is mounted as RO
+	 * or if flush_merge is not passed in mount option.
+	 */
+	if ((*flags & MS_RDONLY) || !test_opt(sbi, FLUSH_MERGE)) {
+		destroy_flush_cmd_control(sbi);
+	} else if (test_opt(sbi, FLUSH_MERGE) &&
+					!sbi->sm_info->cmd_control_info) {
+		err = create_flush_cmd_control(sbi);
+		if (err)
+			goto restore_gc;
 	}
 skip:
 	/* Update the POSIXACL Flag */
 	 sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
 		(test_opt(sbi, POSIX_ACL) ? MS_POSIXACL : 0);
 	return 0;
-
+restore_gc:
+	if (need_restart_gc) {
+		if (start_gc_thread(sbi))
+			f2fs_msg(sbi->sb, KERN_WARNING,
+				"background gc thread is stop");
+	} else if (need_stop_gc) {
+		stop_gc_thread(sbi);
+	}
 restore_opts:
 	sbi->mount_opt = org_mount_opt;
 	sbi->active_logs = active_logs;