From:   Chengguang Xu <cgxu519@mykernel.net>
To:     miklos@szeredi.hu, jack@suse.cz, amir73il@gmail.com
Cc:     linux-unionfs@vger.kernel.org, linux-fsdevel@vger.kernel.org,
        linux-kernel@vger.kernel.org,
        Chengguang Xu <charliecgxu@tencent.com>
Message-ID: <20211122030038.1938875-4-cgxu519@mykernel.net>
Subject: [RFC PATCH V6 3/7] ovl: implement overlayfs' own ->write_inode operation
Date:   Mon, 22 Nov 2021 11:00:34 +0800
In-Reply-To: <20211122030038.1938875-1-cgxu519@mykernel.net>
References: <20211122030038.1938875-1-cgxu519@mykernel.net>
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From: Chengguang Xu <charliecgxu@tencent.com>

Sync dirty data and meta of upper inode in overlayfs' ->write_inode()
and redirty overlayfs' inode.

Signed-off-by: Chengguang Xu <charliecgxu@tencent.com>
---
 fs/overlayfs/super.c | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c
index 18a12088a37b..12acf0ec7395 100644
--- a/fs/overlayfs/super.c
+++ b/fs/overlayfs/super.c
@@ -15,6 +15,7 @@
 #include <linux/seq_file.h>
 #include <linux/posix_acl_xattr.h>
 #include <linux/exportfs.h>
+#include <linux/writeback.h>
 #include "overlayfs.h"
=20
 MODULE_AUTHOR("Miklos Szeredi <miklos@szeredi.hu>");
@@ -406,12 +407,32 @@ static int ovl_remount(struct super_block *sb, int *f=
lags, char *data)
 =09return ret;
 }
=20
+static int ovl_write_inode(struct inode *inode,
+=09=09=09   struct writeback_control *wbc)
+{
+=09struct ovl_fs *ofs =3D inode->i_sb->s_fs_info;
+=09struct inode *upper_inode =3D ovl_inode_upper(inode);
+=09int ret =3D 0;
+
+=09if (!upper_inode)
+=09=09return 0;
+
+=09if (!ovl_should_sync(ofs))
+=09=09return 0;
+
+=09ret =3D write_inode_now(upper_inode, wbc->sync_mode =3D=3D WB_SYNC_ALL)=
;
+=09mark_inode_dirty(inode);
+
+=09return ret;
+}
+
 static const struct super_operations ovl_super_operations =3D {
 =09.alloc_inode=09=3D ovl_alloc_inode,
 =09.free_inode=09=3D ovl_free_inode,
 =09.destroy_inode=09=3D ovl_destroy_inode,
 =09.drop_inode=09=3D generic_delete_inode,
 =09.put_super=09=3D ovl_put_super,
+=09.write_inode=09=3D ovl_write_inode,
 =09.sync_fs=09=3D ovl_sync_fs,
 =09.statfs=09=09=3D ovl_statfs,
 =09.show_options=09=3D ovl_show_options,
--=20
2.27.0