1 files changed, 137 insertions, 0 deletions
diff --git a/fs/aufs/dcsub.h b/fs/aufs/dcsub.h
new file mode 100644
index 000000000000..36f7fcdd7f23
--- /dev/null
+++ b/fs/aufs/dcsub.h
@@ -0,0 +1,137 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2005-2020 Junjiro R. Okajima
+ *
+ * This program, aufs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+/*
+ * sub-routines for dentry cache
+ */
+
+#ifndef __AUFS_DCSUB_H__
+#define __AUFS_DCSUB_H__
+
+#ifdef __KERNEL__
+
+#include <linux/dcache.h>
+#include <linux/fs.h>
+
+struct au_dpage {
+	int ndentry;
+	struct dentry **dentries;
+};
+
+struct au_dcsub_pages {
+	int ndpage;
+	struct au_dpage *dpages;
+};
+
+/* ---------------------------------------------------------------------- */
+
+/* dcsub.c */
+int au_dpages_init(struct au_dcsub_pages *dpages, gfp_t gfp);
+void au_dpages_free(struct au_dcsub_pages *dpages);
+typedef int (*au_dpages_test)(struct dentry *dentry, void *arg);
+int au_dcsub_pages(struct au_dcsub_pages *dpages, struct dentry *root,
+		   au_dpages_test test, void *arg);
+int au_dcsub_pages_rev(struct au_dcsub_pages *dpages, struct dentry *dentry,
+		       int do_include, au_dpages_test test, void *arg);
+int au_dcsub_pages_rev_aufs(struct au_dcsub_pages *dpages,
+			    struct dentry *dentry, int do_include);
+int au_test_subdir(struct dentry *d1, struct dentry *d2);
+
+/* ---------------------------------------------------------------------- */
+
+/*
+ * todo: in linux-3.13, several similar (but faster) helpers are added to
+ * include/linux/dcache.h. Try them (in the future).
+ */
+
+static inline int au_d_hashed_positive(struct dentry *d)
+{
+	int err;
+	struct inode *inode = d_inode(d);
+
+	err = 0;
+	if (unlikely(d_unhashed(d)
+		     || d_is_negative(d)
+		     || !inode->i_nlink))
+		err = -ENOENT;
+	return err;
+}
+
+static inline int au_d_linkable(struct dentry *d)
+{
+	int err;
+	struct inode *inode = d_inode(d);
+
+	err = au_d_hashed_positive(d);
+	if (err
+	    && d_is_positive(d)
+	    && (inode->i_state & I_LINKABLE))
+		err = 0;
+	return err;
+}
+
+static inline int au_d_alive(struct dentry *d)
+{
+	int err;
+	struct inode *inode;
+
+	err = 0;
+	if (!IS_ROOT(d))
+		err = au_d_hashed_positive(d);
+	else {
+		inode = d_inode(d);
+		if (unlikely(d_unlinked(d)
+			     || d_is_negative(d)
+			     || !inode->i_nlink))
+			err = -ENOENT;
+	}
+	return err;
+}
+
+static inline int au_alive_dir(struct dentry *d)
+{
+	int err;
+
+	err = au_d_alive(d);
+	if (unlikely(err || IS_DEADDIR(d_inode(d))))
+		err = -ENOENT;
+	return err;
+}
+
+static inline int au_qstreq(struct qstr *a, struct qstr *b)
+{
+	return a->len == b->len
+		&& !memcmp(a->name, b->name, a->len);
+}
+
+/*
+ * by the commit
+ * 360f547 2015-01-25 dcache: let the dentry count go down to zero without
+ *			taking d_lock
+ * the type of d_lockref.count became int, but the inlined function d_count()
+ * still returns unsigned int.
+ * I don't know why. Maybe it is for every d_count() users?
+ * Anyway au_dcount() lives on.
+ */
+static inline int au_dcount(struct dentry *d)
+{
+	return (int)d_count(d);
+}
+
+#endif /* __KERNEL__ */
+#endif /* __AUFS_DCSUB_H__ */