[PATCH v13 22/28] ovl: Set redirect on upper inode when it is linked

[Vivek Goyal <vgoyal@redhat.com>]

When we create a hardlink to a metacopy upper file, first the redirect
on that inode. Path based lookup will not work with newly created link
and redirect will solve that issue.

Also use absolute redirect as two hardlinks could be in different directores
and relative redirect will not work.

Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
---
 fs/overlayfs/dir.c | 18 ++++++++++++++----
 1 file changed, 14 insertions(+), 4 deletions(-)

diff --git a/fs/overlayfs/dir.c b/fs/overlayfs/dir.c
index 7c0a02d9f6bd..ccbe061fc4ba 100644
--- a/fs/overlayfs/dir.c
+++ b/fs/overlayfs/dir.c
@@ -24,6 +24,8 @@ module_param_named(redirect_max, ovl_redirect_max, ushort, 0644);
 MODULE_PARM_DESC(ovl_redirect_max,
 		 "Maximum length of absolute redirect xattr value");
 
+static int ovl_set_redirect(struct dentry *dentry, bool samedir);
+
 int ovl_cleanup(struct inode *wdir, struct dentry *wdentry)
 {
 	int err;
@@ -468,6 +470,9 @@ static int ovl_create_or_link(struct dentry *dentry, struct inode *inode,
 	const struct cred *old_cred;
 	struct cred *override_cred;
 	struct dentry *parent = dentry->d_parent;
+	struct dentry *hardlink_upper;
+
+	hardlink_upper = hardlink ? ovl_dentry_upper(hardlink) : NULL;
 
 	err = ovl_copy_up(parent);
 	if (err)
@@ -502,12 +507,18 @@ static int ovl_create_or_link(struct dentry *dentry, struct inode *inode,
 		put_cred(override_creds(override_cred));
 		put_cred(override_cred);
 
+		if (hardlink && ovl_is_metacopy_dentry(hardlink)) {
+			err = ovl_set_redirect(hardlink, false);
+			if (err)
+				goto out_revert_creds;
+		}
+
 		if (!ovl_dentry_is_whiteout(dentry))
 			err = ovl_create_upper(dentry, inode, attr,
-						hardlink);
+					       hardlink_upper);
 		else
 			err = ovl_create_over_whiteout(dentry, inode, attr,
-							hardlink);
+					               hardlink_upper);
 	}
 out_revert_creds:
 	revert_creds(old_cred);
@@ -606,8 +617,7 @@ static int ovl_link(struct dentry *old, struct inode *newdir,
 	inode = d_inode(old);
 	ihold(inode);
 
-	err = ovl_create_or_link(new, inode, NULL, ovl_dentry_upper(old),
-				 ovl_type_origin(old));
+	err = ovl_create_or_link(new, inode, NULL, old, ovl_type_origin(old));
 	if (err)
 		iput(inode);
 
-- 
2.13.6