ovl: mark upper dir with type origin entries "impure"

When moving a merge dir or non-dir with copy up origin into a non-merge
upper dir (a.k.a pure upper dir), we are marking the target parent dir
"impure". ovl_iterate() iterates pure upper dirs directly, because there is
no need to filter out whiteouts and merge dir content with lower dir. But
for the case of an "impure" upper dir, ovl_iterate() will not be able to
iterate the real upper dir directly, because it will need to lookup the
origin inode and use it to fill d_ino.

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

1 files changed, 45 insertions, 0 deletions

diff --git a/fs/overlayfs/dir.c b/fs/overlayfs/dir.c
index 369ee7c4cdc0..f2a118ba00e4 100644
--- a/fs/overlayfs/dir.c
+++ b/fs/overlayfs/dir.c
@@ -149,6 +149,22 @@ static int ovl_set_opaque(struct dentry *dentry, struct dentry *upperdentry)
 	return ovl_set_opaque_xerr(dentry, upperdentry, -EIO);
 }
 
+static int ovl_set_impure(struct dentry *dentry, struct dentry *upperdentry)
+{
+	int err;
+
+	/*
+	 * Do not fail when upper doesn't support xattrs.
+	 * Upper inodes won't have origin nor redirect xattr anyway.
+	 */
+	err = ovl_check_setxattr(dentry, upperdentry, OVL_XATTR_IMPURE,
+				 "y", 1, 0);
+	if (!err)
+		ovl_dentry_set_impure(dentry);
+
+	return err;
+}
+
 /* Common operations required to be done after creation of file on upper */
 static void ovl_instantiate(struct dentry *dentry, struct inode *inode,
 			    struct dentry *newdentry, bool hardlink)
@@ -173,6 +189,11 @@ static bool ovl_type_merge(struct dentry *dentry)
 	return OVL_TYPE_MERGE(ovl_path_type(dentry));
 }
 
+static bool ovl_type_origin(struct dentry *dentry)
+{
+	return OVL_TYPE_ORIGIN(ovl_path_type(dentry));
+}
+
 static int ovl_create_upper(struct dentry *dentry, struct inode *inode,
 			    struct cattr *attr, struct dentry *hardlink)
 {
@@ -952,6 +973,30 @@ static int ovl_rename(struct inode *olddir, struct dentry *old,
 	old_upperdir = ovl_dentry_upper(old->d_parent);
 	new_upperdir = ovl_dentry_upper(new->d_parent);
 
+	if (!samedir) {
+		/*
+		 * When moving a merge dir or non-dir with copy up origin into
+		 * a non-merge upper dir (a.k.a pure upper dir), we are making
+		 * the target parent dir "impure". ovl_iterate() iterates pure
+		 * upper dirs directly, because there is no need to filter out
+		 * whiteouts and merge dir content with lower dir. But for the
+		 * case of an "impure" upper dir, ovl_iterate() cannot iterate
+		 * the real directory directly, because it looks for the inode
+		 * numbers to fill d_ino in the entries origin inode.
+		 */
+		if (ovl_type_origin(old) && !ovl_type_merge(new->d_parent)) {
+			err = ovl_set_impure(new->d_parent, new_upperdir);
+			if (err)
+				goto out_revert_creds;
+		}
+		if (!overwrite && ovl_type_origin(new) &&
+		    !ovl_type_merge(old->d_parent)) {
+			err = ovl_set_impure(old->d_parent, old_upperdir);
+			if (err)
+				goto out_revert_creds;
+		}
+	}
+
 	trap = lock_rename(new_upperdir, old_upperdir);
 
 	olddentry = lookup_one_len(old->d_name.name, old_upperdir,