ovl: use ovl_lookup_upper() wrapper

Introduce ovl_lookup_upper() as a simple wrapper around lookup_one().
Make it clear in the helper's name that this only operates on the upper
layer. The wrapper will take upper layer's idmapping into account when
checking permission in lookup_one().

Cc: <linux-unionfs@vger.kernel.org>
Tested-by: Giuseppe Scrivano <gscrivan@redhat.com>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>

1 files changed, 15 insertions, 16 deletions

diff --git a/fs/overlayfs/dir.c b/fs/overlayfs/dir.c
index 8f7917474ee2..927abe7e7ab2 100644
--- a/fs/overlayfs/dir.c
+++ b/fs/overlayfs/dir.c
@@ -51,7 +51,7 @@ struct dentry *ovl_lookup_temp(struct ovl_fs *ofs, struct dentry *workdir)
 	/* counter is allowed to wrap, since temp dentries are ephemeral */
 	snprintf(name, sizeof(name), "#%x", atomic_inc_return(&temp_id));
 
-	temp = lookup_one_len(name, workdir, strlen(name));
+	temp = ovl_lookup_upper(ofs, name, workdir, strlen(name));
 	if (!IS_ERR(temp) && temp->d_inode) {
 		pr_err("workdir/%s already exists\n", name);
 		dput(temp);
@@ -155,8 +155,8 @@ int ovl_mkdir_real(struct ovl_fs *ofs, struct inode *dir,
 	 * to it unhashed and negative. If that happens, try to
 	 * lookup a new hashed and positive dentry.
 	 */
-	d = lookup_one_len(dentry->d_name.name, dentry->d_parent,
-			   dentry->d_name.len);
+	d = ovl_lookup_upper(ofs, dentry->d_name.name, dentry->d_parent,
+			     dentry->d_name.len);
 	if (IS_ERR(d)) {
 		pr_warn("failed lookup after mkdir (%pd2, err=%i).\n",
 			dentry, err);
@@ -333,9 +333,8 @@ static int ovl_create_upper(struct dentry *dentry, struct inode *inode,
 
 	inode_lock_nested(udir, I_MUTEX_PARENT);
 	newdentry = ovl_create_real(ofs, udir,
-				    lookup_one_len(dentry->d_name.name,
-						   upperdir,
-						   dentry->d_name.len),
+				    ovl_lookup_upper(ofs, dentry->d_name.name,
+						     upperdir, dentry->d_name.len),
 				    attr);
 	err = PTR_ERR(newdentry);
 	if (IS_ERR(newdentry))
@@ -488,8 +487,8 @@ static int ovl_create_over_whiteout(struct dentry *dentry, struct inode *inode,
 	if (err)
 		goto out;
 
-	upper = lookup_one_len(dentry->d_name.name, upperdir,
-			       dentry->d_name.len);
+	upper = ovl_lookup_upper(ofs, dentry->d_name.name, upperdir,
+				 dentry->d_name.len);
 	err = PTR_ERR(upper);
 	if (IS_ERR(upper))
 		goto out_unlock;
@@ -771,8 +770,8 @@ static int ovl_remove_and_whiteout(struct dentry *dentry,
 	if (err)
 		goto out_dput;
 
-	upper = lookup_one_len(dentry->d_name.name, upperdir,
-			       dentry->d_name.len);
+	upper = ovl_lookup_upper(ofs, dentry->d_name.name, upperdir,
+				 dentry->d_name.len);
 	err = PTR_ERR(upper);
 	if (IS_ERR(upper))
 		goto out_unlock;
@@ -819,8 +818,8 @@ static int ovl_remove_upper(struct dentry *dentry, bool is_dir,
 	}
 
 	inode_lock_nested(dir, I_MUTEX_PARENT);
-	upper = lookup_one_len(dentry->d_name.name, upperdir,
-			       dentry->d_name.len);
+	upper = ovl_lookup_upper(ofs, dentry->d_name.name, upperdir,
+				 dentry->d_name.len);
 	err = PTR_ERR(upper);
 	if (IS_ERR(upper))
 		goto out_unlock;
@@ -1195,8 +1194,8 @@ static int ovl_rename(struct user_namespace *mnt_userns, struct inode *olddir,
 
 	trap = lock_rename(new_upperdir, old_upperdir);
 
-	olddentry = lookup_one_len(old->d_name.name, old_upperdir,
-				   old->d_name.len);
+	olddentry = ovl_lookup_upper(ofs, old->d_name.name, old_upperdir,
+				     old->d_name.len);
 	err = PTR_ERR(olddentry);
 	if (IS_ERR(olddentry))
 		goto out_unlock;
@@ -1205,8 +1204,8 @@ static int ovl_rename(struct user_namespace *mnt_userns, struct inode *olddir,
 	if (!ovl_matches_upper(old, olddentry))
 		goto out_dput_old;
 
-	newdentry = lookup_one_len(new->d_name.name, new_upperdir,
-				   new->d_name.len);
+	newdentry = ovl_lookup_upper(ofs, new->d_name.name, new_upperdir,
+				     new->d_name.len);
 	err = PTR_ERR(newdentry);
 	if (IS_ERR(newdentry))
 		goto out_dput_old;