[PATCH 1/2] exfat: call sync_filesystem for read-only remount

[Hyunchul Lee <hyc.lee@gmail.com>]

We need to commit dirty metadata and pages to disk
before remounting exfat as read-only.

This fixes a failure in xfstests generic/452

Signed-off-by: Hyunchul Lee <hyc.lee@gmail.com>
---
 fs/exfat/super.c | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/fs/exfat/super.c b/fs/exfat/super.c
index e650e65536f8..61c6cf240c19 100644
--- a/fs/exfat/super.c
+++ b/fs/exfat/super.c
@@ -693,10 +693,29 @@ static void exfat_free(struct fs_context *fc)
 	}
 }
 
+static int exfat_reconfigure(struct fs_context *fc)
+{
+	struct super_block *sb = fc->root->d_sb;
+	int ret;
+	bool new_rdonly;
+
+	new_rdonly = fc->sb_flags & SB_RDONLY;
+	if (new_rdonly != sb_rdonly(sb)) {
+		if (new_rdonly) {
+			/* volume flag will be updated in exfat_sync_fs */
+			ret = sync_filesystem(sb);
+			if (ret < 0)
+				return ret;
+		}
+	}
+	return 0;
+}
+
 static const struct fs_context_operations exfat_context_ops = {
 	.parse_param	= exfat_parse_param,
 	.get_tree	= exfat_get_tree,
 	.free		= exfat_free,
+	.reconfigure	= exfat_reconfigure,
 };
 
 static int exfat_init_fs_context(struct fs_context *fc)
-- 
2.17.1