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From:   Chengguang Xu <cgxu519@mykernel.net>
To:     miklos@szeredi.hu, jack@suse.cz, amir73il@gmail.com
Cc:     linux-fsdevel@vger.kernel.org, linux-unionfs@vger.kernel.org,
        linux-kernel@vger.kernel.org, Chengguang Xu <cgxu519@mykernel.net>
Message-ID: <20210923130814.140814-3-cgxu519@mykernel.net>
Subject: [RFC PATCH v5 02/10] ovl: implement ->writepages operation
Date:   Thu, 23 Sep 2021 21:08:06 +0800
In-Reply-To: <20210923130814.140814-1-cgxu519@mykernel.net>
References: <20210923130814.140814-1-cgxu519@mykernel.net>
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Precedence: bulk

Implement overlayfs' ->writepages operation so that
we can sync dirty data/metadata to upper filesystem.

Signed-off-by: Chengguang Xu <cgxu519@mykernel.net>
---
 fs/overlayfs/inode.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/fs/overlayfs/inode.c b/fs/overlayfs/inode.c
index 832b17589733..d854e59a3710 100644
--- a/fs/overlayfs/inode.c
+++ b/fs/overlayfs/inode.c
@@ -659,9 +659,22 @@ static const struct inode_operations ovl_special_inode=
_operations =3D {
 =09.update_time=09=3D ovl_update_time,
 };
=20
+static int ovl_writepages(struct address_space *mapping,
+=09=09=09  struct writeback_control *wbc)
+{
+=09struct inode *inode =3D mapping->host;
+=09struct ovl_fs *ofs =3D inode->i_sb->s_fs_info;
+=09struct inode *upper =3D ovl_inode_upper(inode);
+
+=09if (!ovl_should_sync(ofs))
+=09=09return 0;
+=09return filemap_fdatawrite_wbc(upper->i_mapping, wbc);
+}
+
 static const struct address_space_operations ovl_aops =3D {
 =09/* For O_DIRECT dentry_open() checks f_mapping->a_ops->direct_IO */
 =09.direct_IO=09=09=3D noop_direct_IO,
+=09.writepages=09=09=3D ovl_writepages,
 };
=20
 /*
--=20
2.27.0