ovl: Move the copy up helpers to copy_up.c

Right now two copy up helpers are in inode.c.  Amir suggested it might be
better to move these to copy_up.c.

There will one more related function which will come in later patch.

Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>

1 files changed, 32 insertions, 0 deletions

diff --git a/fs/overlayfs/copy_up.c b/fs/overlayfs/copy_up.c
index 65ee07e36141..304b26860743 100644
--- a/fs/overlayfs/copy_up.c
+++ b/fs/overlayfs/copy_up.c
@@ -779,6 +779,38 @@ int ovl_copy_up_flags(struct dentry *dentry, int flags)
 	return err;
 }
 
+static bool ovl_open_need_copy_up(struct dentry *dentry, int flags)
+{
+	/* Copy up of disconnected dentry does not set upper alias */
+	if (ovl_dentry_upper(dentry) &&
+	    (ovl_dentry_has_upper_alias(dentry) ||
+	     (dentry->d_flags & DCACHE_DISCONNECTED)))
+		return false;
+
+	if (special_file(d_inode(dentry)->i_mode))
+		return false;
+
+	if (!(OPEN_FMODE(flags) & FMODE_WRITE) && !(flags & O_TRUNC))
+		return false;
+
+	return true;
+}
+
+int ovl_open_maybe_copy_up(struct dentry *dentry, unsigned int file_flags)
+{
+	int err = 0;
+
+	if (ovl_open_need_copy_up(dentry, file_flags)) {
+		err = ovl_want_write(dentry);
+		if (!err) {
+			err = ovl_copy_up_flags(dentry, file_flags);
+			ovl_drop_write(dentry);
+		}
+	}
+
+	return err;
+}
+
 int ovl_copy_up(struct dentry *dentry)
 {
 	return ovl_copy_up_flags(dentry, 0);