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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: <20210923130814.140814-6-cgxu519@mykernel.net>
Subject: [RFC PATCH v5 05/10] ovl: mark overlayfs' inode dirty on shared mmap
Date:   Thu, 23 Sep 2021 21:08:09 +0800
In-Reply-To: <20210923130814.140814-1-cgxu519@mykernel.net>
References: <20210923130814.140814-1-cgxu519@mykernel.net>
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Overlayfs cannot be notified when mmapped area gets dirty,
so we need to proactively mark inode dirty in ->mmap operation.

Signed-off-by: Chengguang Xu <cgxu519@mykernel.net>
---
 fs/overlayfs/file.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/fs/overlayfs/file.c b/fs/overlayfs/file.c
index d081faa55e83..f9dc5249c183 100644
--- a/fs/overlayfs/file.c
+++ b/fs/overlayfs/file.c
@@ -482,6 +482,12 @@ static int ovl_mmap(struct file *file, struct vm_area_=
struct *vma)
 =09revert_creds(old_cred);
 =09ovl_file_accessed(file);
=20
+=09if (!ret) {
+=09=09if (ovl_inode_upper(file_inode(file)) &&
+=09=09    vma->vm_flags & VM_SHARED)
+=09=09=09ovl_mark_inode_dirty(file_inode(file));
+=09}
+
 =09return ret;
 }
=20
--=20
2.27.0