[PATCH v4 2/8] ovl: setup overlayfs' private bdi

[Josef Bacik <josef@toxicpanda.com>]

From: Chengguang Xu <charliecgxu@tencent.com>

Setup overlayfs' private bdi so that we can collect
overlayfs' own dirty inodes.

Signed-off-by: Chengguang Xu <charliecgxu@tencent.com>
[josef: only for an overlay that tracks dirty inodes]
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
---
 fs/overlayfs/super.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c
index 81da70fd53a6..22a8d4eb3b7c 100644
--- a/fs/overlayfs/super.c
+++ b/fs/overlayfs/super.c
@@ -1490,6 +1490,16 @@ static int ovl_fill_super_creds(struct fs_context *fc, struct super_block *sb)
 		if (!ofs->workdir)
 			sb->s_flags |= SB_RDONLY;
 
+		/*
+		 * Dirty overlay inodes go on the lists of this bdi.  fsync_mode
+		 * is final once ovl_get_workdir() has returned.
+		 */
+		if (ovl_tracks_dirty(ofs)) {
+			err = super_setup_bdi(sb);
+			if (err)
+				return err;
+		}
+
 		sb->s_stack_depth = upper_sb->s_stack_depth;
 		sb->s_time_gran = upper_sb->s_time_gran;
 	}

-- 
2.55.0