Implement stacked mmap.
Signed-off-by: Miklos Szeredi <mszeredi@xxxxxxxxxx>
---
fs/overlayfs/file.c | 28 ++++++++++++++++++++++++++++
1 file changed, 28 insertions(+)
diff --git a/fs/overlayfs/file.c b/fs/overlayfs/file.c
index 4417527667ff..f1cc2fdc62c1 100644
--- a/fs/overlayfs/file.c
+++ b/fs/overlayfs/file.c
@@ -241,6 +241,33 @@ static int ovl_fsync(struct file *file, loff_t start, loff_t end, int datasync)
return ret;
}
+static int ovl_mmap(struct file *file, struct vm_area_struct *vma)
+{
+ struct fd real;
+ const struct cred *old_cred;
+ int ret;
+
+ ret = ovl_real_file(file, &real);
+ if (ret)
+ return ret;
+
+ /* transfer ref: */
+ fput(vma->vm_file);
+ vma->vm_file = get_file(real.file);
+ fdput(real);
+
+ if (!vma->vm_file->f_op->mmap)
+ return -ENODEV;
+
+ old_cred = ovl_override_creds(file_inode(file)->i_sb);
+ ret = call_mmap(vma->vm_file, vma);
+ revert_creds(old_cred);
+
+ ovl_file_accessed(file);
+
+ return ret;
+}
+
const struct file_operations ovl_file_operations = {
.open = ovl_open,
.release = ovl_release,
@@ -248,4 +275,5 @@ const struct file_operations ovl_file_operations = {
.read_iter = ovl_read_iter,
.write_iter = ovl_write_iter,
.fsync = ovl_fsync,
+ .mmap = ovl_mmap,
};
--
2.14.3
