aufs5.7-20200622.patch

+#endif
+
+/* ---------------------------------------------------------------------- */
+
+static inline aufs_bindex_t au_sbbot(struct super_block *sb)
+{
+	SiMustAnyLock(sb);
+	return au_sbi(sb)->si_bbot;
+}
+
+static inline unsigned int au_mntflags(struct super_block *sb)
+{
+	SiMustAnyLock(sb);
+	return au_sbi(sb)->si_mntflags;
+}
+
+static inline unsigned int au_sigen(struct super_block *sb)
+{
+	SiMustAnyLock(sb);
+	return au_sbi(sb)->si_generation;
+}
+
+static inline struct au_branch *au_sbr(struct super_block *sb,
+				       aufs_bindex_t bindex)
+{
+	SiMustAnyLock(sb);
+	return au_sbi(sb)->si_branch[0 + bindex];
+}
+
+static inline loff_t au_xi_maxent(struct super_block *sb)
+{
+	SiMustAnyLock(sb);
+	return au_sbi(sb)->si_ximaxent;
+}
+
+#endif /* __KERNEL__ */
+#endif /* __AUFS_SUPER_H__ */
diff -Naur null/fs/aufs/sysaufs.c linux-5.7/fs/aufs/sysaufs.c
--- /dev/null
+++ linux-5.7/fs/aufs/sysaufs.c	2020-08-22 11:57:41.471782894 +0200
@@ -0,0 +1,93 @@
+// 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/>.
+ */
+
+/*
+ * sysfs interface and lifetime management
+ * they are necessary regardless sysfs is disabled.
+ */
+
+#include <linux/random.h>
+#include "aufs.h"
+
+unsigned long sysaufs_si_mask;
+struct kset *sysaufs_kset;
+
+#define AuSiAttr(_name) { \
+	.attr   = { .name = __stringify(_name), .mode = 0444 },	\
+	.show   = sysaufs_si_##_name,				\
+}
+
+static struct sysaufs_si_attr sysaufs_si_attr_xi_path = AuSiAttr(xi_path);
+struct attribute *sysaufs_si_attrs[] = {
+	&sysaufs_si_attr_xi_path.attr,
+	NULL,
+};
+
+static const struct sysfs_ops au_sbi_ops = {
+	.show   = sysaufs_si_show
+};
+
+static struct kobj_type au_sbi_ktype = {
+	.release	= au_si_free,
+	.sysfs_ops	= &au_sbi_ops,
+	.default_attrs	= sysaufs_si_attrs
+};
+
+/* ---------------------------------------------------------------------- */
+
+int sysaufs_si_init(struct au_sbinfo *sbinfo)
+{
+	int err;
+
+	sbinfo->si_kobj.kset = sysaufs_kset;
+	/* cf. sysaufs_name() */
+	err = kobject_init_and_add
+		(&sbinfo->si_kobj, &au_sbi_ktype, /*&sysaufs_kset->kobj*/NULL,
+		 SysaufsSiNamePrefix "%lx", sysaufs_si_id(sbinfo));
+
+	return err;
+}
+
+void sysaufs_fin(void)
+{
+	sysfs_remove_group(&sysaufs_kset->kobj, sysaufs_attr_group);
+	kset_unregister(sysaufs_kset);
+}
+
+int __init sysaufs_init(void)
+{
+	int err;
+
+	do {
+		get_random_bytes(&sysaufs_si_mask, sizeof(sysaufs_si_mask));
+	} while (!sysaufs_si_mask);
+
+	err = -EINVAL;
+	sysaufs_kset = kset_create_and_add(AUFS_NAME, NULL, fs_kobj);
+	if (unlikely(!sysaufs_kset))
+		goto out;
+	err = PTR_ERR(sysaufs_kset);
+	if (IS_ERR(sysaufs_kset))
+		goto out;
+	err = sysfs_create_group(&sysaufs_kset->kobj, sysaufs_attr_group);
+	if (unlikely(err))
+		kset_unregister(sysaufs_kset);
+
+out:
+	return err;
+}
diff -Naur null/fs/aufs/sysaufs.h linux-5.7/fs/aufs/sysaufs.h
--- /dev/null
+++ linux-5.7/fs/aufs/sysaufs.h	2020-08-22 11:57:41.471782894 +0200
@@ -0,0 +1,102 @@
+/* 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/>.
+ */
+
+/*
+ * sysfs interface and mount lifetime management
+ */
+
+#ifndef __SYSAUFS_H__
+#define __SYSAUFS_H__
+
+#ifdef __KERNEL__
+
+#include <linux/sysfs.h>
+#include "module.h"
+
+struct super_block;
+struct au_sbinfo;
+
+struct sysaufs_si_attr {
+	struct attribute attr;
+	int (*show)(struct seq_file *seq, struct super_block *sb);
+};
+
+/* ---------------------------------------------------------------------- */
+
+/* sysaufs.c */
+extern unsigned long sysaufs_si_mask;
+extern struct kset *sysaufs_kset;
+extern struct attribute *sysaufs_si_attrs[];
+int sysaufs_si_init(struct au_sbinfo *sbinfo);
+int __init sysaufs_init(void);
+void sysaufs_fin(void);
+
+/* ---------------------------------------------------------------------- */
+
+/* some people doesn't like to show a pointer in kernel */
+static inline unsigned long sysaufs_si_id(struct au_sbinfo *sbinfo)
+{
+	return sysaufs_si_mask ^ (unsigned long)sbinfo;
+}
+
+#define SysaufsSiNamePrefix	"si_"
+#define SysaufsSiNameLen	(sizeof(SysaufsSiNamePrefix) + 16)
+static inline void sysaufs_name(struct au_sbinfo *sbinfo, char *name)
+{
+	snprintf(name, SysaufsSiNameLen, SysaufsSiNamePrefix "%lx",
+		 sysaufs_si_id(sbinfo));
+}
+
+struct au_branch;
+#ifdef CONFIG_SYSFS
+/* sysfs.c */
+extern struct attribute_group *sysaufs_attr_group;
+
+int sysaufs_si_xi_path(struct seq_file *seq, struct super_block *sb);
+ssize_t sysaufs_si_show(struct kobject *kobj, struct attribute *attr,
+			 char *buf);
+long au_brinfo_ioctl(struct file *file, unsigned long arg);
+#ifdef CONFIG_COMPAT
+long au_brinfo_compat_ioctl(struct file *file, unsigned long arg);
+#endif
+
+void sysaufs_br_init(struct au_branch *br);
+void sysaufs_brs_add(struct super_block *sb, aufs_bindex_t bindex);
+void sysaufs_brs_del(struct super_block *sb, aufs_bindex_t bindex);
+
+#define sysaufs_brs_init()	do {} while (0)
+
+#else
+#define sysaufs_attr_group	NULL
+
+AuStubInt0(sysaufs_si_xi_path, struct seq_file *seq, struct super_block *sb)
+AuStub(ssize_t, sysaufs_si_show, return 0, struct kobject *kobj,
+       struct attribute *attr, char *buf)
+AuStubVoid(sysaufs_br_init, struct au_branch *br)
+AuStubVoid(sysaufs_brs_add, struct super_block *sb, aufs_bindex_t bindex)
+AuStubVoid(sysaufs_brs_del, struct super_block *sb, aufs_bindex_t bindex)
+
+static inline void sysaufs_brs_init(void)
+{
+	sysaufs_brs = 0;
+}
+
+#endif /* CONFIG_SYSFS */
+
+#endif /* __KERNEL__ */
+#endif /* __SYSAUFS_H__ */
diff -Naur null/fs/aufs/sysfs.c linux-5.7/fs/aufs/sysfs.c
--- /dev/null
+++ linux-5.7/fs/aufs/sysfs.c	2020-08-22 11:57:41.471782894 +0200
@@ -0,0 +1,374 @@
+// 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/>.
+ */
+
+/*
+ * sysfs interface
+ */
+
+#include <linux/compat.h>
+#include <linux/seq_file.h>
+#include "aufs.h"
+
+#ifdef CONFIG_AUFS_FS_MODULE
+/* this entry violates the "one line per file" policy of sysfs */
+static ssize_t config_show(struct kobject *kobj, struct kobj_attribute *attr,
+			   char *buf)
+{
+	ssize_t err;
+	static char *conf =
+/* this file is generated at compiling */
+#include "conf.str"
+		;
+
+	err = snprintf(buf, PAGE_SIZE, conf);
+	if (unlikely(err >= PAGE_SIZE))
+		err = -EFBIG;
+	return err;
+}
+
+static struct kobj_attribute au_config_attr = __ATTR_RO(config);
+#endif
+
+static struct attribute *au_attr[] = {
+#ifdef CONFIG_AUFS_FS_MODULE
+	&au_config_attr.attr,
+#endif
+	NULL,	/* need to NULL terminate the list of attributes */
+};
+
+static struct attribute_group sysaufs_attr_group_body = {
+	.attrs = au_attr
+};
+
+struct attribute_group *sysaufs_attr_group = &sysaufs_attr_group_body;
+
+/* ---------------------------------------------------------------------- */
+
+int sysaufs_si_xi_path(struct seq_file *seq, struct super_block *sb)
+{
+	int err;
+
+	SiMustAnyLock(sb);
+
+	err = 0;
+	if (au_opt_test(au_mntflags(sb), XINO)) {
+		err = au_xino_path(seq, au_sbi(sb)->si_xib);
+		seq_putc(seq, '\n');
+	}
+	return err;
+}
+
+/*
+ * the lifetime of branch is independent from the entry under sysfs.
+ * sysfs handles the lifetime of the entry, and never call ->show() after it is
+ * unlinked.
+ */
+static int sysaufs_si_br(struct seq_file *seq, struct super_block *sb,
+			 aufs_bindex_t bindex, int idx)
+{
+	int err;
+	struct path path;
+	struct dentry *root;
+	struct au_branch *br;
+	au_br_perm_str_t perm;
+
+	AuDbg("b%d\n", bindex);
+
+	err = 0;
+	root = sb->s_root;
+	di_read_lock_parent(root, !AuLock_IR);
+	br = au_sbr(sb, bindex);
+
+	switch (idx) {
+	case AuBrSysfs_BR:
+		path.mnt = au_br_mnt(br);
+		path.dentry = au_h_dptr(root, bindex);
+		err = au_seq_path(seq, &path);
+		if (!err) {
+			au_optstr_br_perm(&perm, br->br_perm);
+			seq_printf(seq, "=%s\n", perm.a);
+		}
+		break;
+	case AuBrSysfs_BRID:
+		seq_printf(seq, "%d\n", br->br_id);
+		break;
+	}
+	di_read_unlock(root, !AuLock_IR);
+	if (unlikely(err || seq_has_overflowed(seq)))
+		err = -E2BIG;
+
+	return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+static struct seq_file *au_seq(char *p, ssize_t len)
+{
+	struct seq_file *seq;
+
+	seq = kzalloc(sizeof(*seq), GFP_NOFS);
+	if (seq) {
+		/* mutex_init(&seq.lock); */
+		seq->buf = p;
+		seq->size = len;
+		return seq; /* success */
+	}
+
+	seq = ERR_PTR(-ENOMEM);
+	return seq;
+}
+
+#define SysaufsBr_PREFIX	"br"
+#define SysaufsBrid_PREFIX	"brid"
+
+/* todo: file size may exceed PAGE_SIZE */
+ssize_t sysaufs_si_show(struct kobject *kobj, struct attribute *attr,
+			char *buf)
+{
+	ssize_t err;
+	int idx;
+	long l;
+	aufs_bindex_t bbot;
+	struct au_sbinfo *sbinfo;
+	struct super_block *sb;
+	struct seq_file *seq;
+	char *name;
+	struct attribute **cattr;
+
+	sbinfo = container_of(kobj, struct au_sbinfo, si_kobj);
+	sb = sbinfo->si_sb;
+
+	/*
+	 * prevent a race condition between sysfs and aufs.
+	 * for instance, sysfs_file_read() calls sysfs_get_active_two() which
+	 * prohibits maintaining the sysfs entries.
+	 * hew we acquire read lock after sysfs_get_active_two().
+	 * on the other hand, the remount process may maintain the sysfs/aufs
+	 * entries after acquiring write lock.
+	 * it can cause a deadlock.
+	 * simply we gave up processing read here.
+	 */
+	err = -EBUSY;
+	if (unlikely(!si_noflush_read_trylock(sb)))
+		goto out;
+
+	seq = au_seq(buf, PAGE_SIZE);
+	err = PTR_ERR(seq);
+	if (IS_ERR(seq))
+		goto out_unlock;
+
+	name = (void *)attr->name;
+	cattr = sysaufs_si_attrs;
+	while (*cattr) {
+		if (!strcmp(name, (*cattr)->name)) {
+			err = container_of(*cattr, struct sysaufs_si_attr, attr)
+				->show(seq, sb);
+			goto out_seq;
+		}
+		cattr++;
+	}
+
+	if (!strncmp(name, SysaufsBrid_PREFIX,
+		     sizeof(SysaufsBrid_PREFIX) - 1)) {
+		idx = AuBrSysfs_BRID;
+		name += sizeof(SysaufsBrid_PREFIX) - 1;
+	} else if (!strncmp(name, SysaufsBr_PREFIX,
+			    sizeof(SysaufsBr_PREFIX) - 1)) {
+		idx = AuBrSysfs_BR;
+		name += sizeof(SysaufsBr_PREFIX) - 1;
+	} else
+		  BUG();
+
+	err = kstrtol(name, 10, &l);
+	if (!err) {
+		bbot = au_sbbot(sb);
+		if (l <= bbot)
+			err = sysaufs_si_br(seq, sb, (aufs_bindex_t)l, idx);
+		else
+			err = -ENOENT;
+	}
+
+out_seq:
+	if (!err) {
+		err = seq->count;
+		/* sysfs limit */
+		if (unlikely(err == PAGE_SIZE))
+			err = -EFBIG;
+	}
+	au_kfree_rcu(seq);
+out_unlock:
+	si_read_unlock(sb);
+out:
+	return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+static int au_brinfo(struct super_block *sb, union aufs_brinfo __user *arg)
+{
+	int err;
+	int16_t brid;
+	aufs_bindex_t bindex, bbot;
+	size_t sz;
+	char *buf;
+	struct seq_file *seq;
+	struct au_branch *br;
+
+	si_read_lock(sb, AuLock_FLUSH);
+	bbot = au_sbbot(sb);
+	err = bbot + 1;
+	if (!arg)
+		goto out;
+
+	err = -ENOMEM;
+	buf = (void *)__get_free_page(GFP_NOFS);
+	if (unlikely(!buf))
+		goto out;
+
+	seq = au_seq(buf, PAGE_SIZE);
+	err = PTR_ERR(seq);
+	if (IS_ERR(seq))
+		goto out_buf;
+
+	sz = sizeof(*arg) - offsetof(union aufs_brinfo, path);
+	for (bindex = 0; bindex <= bbot; bindex++, arg++) {
+		/* VERIFY_WRITE */
+		err = !access_ok(arg, sizeof(*arg));
+		if (unlikely(err))
+			break;
+
+		br = au_sbr(sb, bindex);
+		brid = br->br_id;
+		BUILD_BUG_ON(sizeof(brid) != sizeof(arg->id));
+		err = __put_user(brid, &arg->id);
+		if (unlikely(err))
+			break;
+
+		BUILD_BUG_ON(sizeof(br->br_perm) != sizeof(arg->perm));
+		err = __put_user(br->br_perm, &arg->perm);
+		if (unlikely(err))
+			break;
+
+		err = au_seq_path(seq, &br->br_path);
+		if (unlikely(err))
+			break;
+		seq_putc(seq, '\0');
+		if (!seq_has_overflowed(seq)) {
+			err = copy_to_user(arg->path, seq->buf, seq->count);
+			seq->count = 0;
+			if (unlikely(err))
+				break;
+		} else {
+			err = -E2BIG;
+			goto out_seq;
+		}
+	}
+	if (unlikely(err))
+		err = -EFAULT;
+
+out_seq:
+	au_kfree_rcu(seq);
+out_buf:
+	free_page((unsigned long)buf);
+out:
+	si_read_unlock(sb);
+	return err;
+}
+
+long au_brinfo_ioctl(struct file *file, unsigned long arg)
+{
+	return au_brinfo(file->f_path.dentry->d_sb, (void __user *)arg);
+}
+
+#ifdef CONFIG_COMPAT
+long au_brinfo_compat_ioctl(struct file *file, unsigned long arg)
+{
+	return au_brinfo(file->f_path.dentry->d_sb, compat_ptr(arg));
+}
+#endif
+
+/* ---------------------------------------------------------------------- */
+
+void sysaufs_br_init(struct au_branch *br)
+{
+	int i;
+	struct au_brsysfs *br_sysfs;
+	struct attribute *attr;
+
+	br_sysfs = br->br_sysfs;
+	for (i = 0; i < ARRAY_SIZE(br->br_sysfs); i++) {
+		attr = &br_sysfs->attr;
+		sysfs_attr_init(attr);
+		attr->name = br_sysfs->name;
+		attr->mode = 0444;
+		br_sysfs++;
+	}
+}
+
+void sysaufs_brs_del(struct super_block *sb, aufs_bindex_t bindex)
+{
+	struct au_branch *br;
+	struct kobject *kobj;
+	struct au_brsysfs *br_sysfs;
+	int i;
+	aufs_bindex_t bbot;
+
+	if (!sysaufs_brs)
+		return;
+
+	kobj = &au_sbi(sb)->si_kobj;
+	bbot = au_sbbot(sb);
+	for (; bindex <= bbot; bindex++) {
+		br = au_sbr(sb, bindex);
+		br_sysfs = br->br_sysfs;
+		for (i = 0; i < ARRAY_SIZE(br->br_sysfs); i++) {
+			sysfs_remove_file(kobj, &br_sysfs->attr);
+			br_sysfs++;
+		}
+	}
+}
+
+void sysaufs_brs_add(struct super_block *sb, aufs_bindex_t bindex)
+{
+	int err, i;
+	aufs_bindex_t bbot;
+	struct kobject *kobj;
+	struct au_branch *br;
+	struct au_brsysfs *br_sysfs;
+
+	if (!sysaufs_brs)
+		return;
+
+	kobj = &au_sbi(sb)->si_kobj;
+	bbot = au_sbbot(sb);
+	for (; bindex <= bbot; bindex++) {
+		br = au_sbr(sb, bindex);
+		br_sysfs = br->br_sysfs;
+		snprintf(br_sysfs[AuBrSysfs_BR].name, sizeof(br_sysfs->name),
+			 SysaufsBr_PREFIX "%d", bindex);
+		snprintf(br_sysfs[AuBrSysfs_BRID].name, sizeof(br_sysfs->name),
+			 SysaufsBrid_PREFIX "%d", bindex);
+		for (i = 0; i < ARRAY_SIZE(br->br_sysfs); i++) {
+			err = sysfs_create_file(kobj, &br_sysfs->attr);
+			if (unlikely(err))
+				pr_warn("failed %s under sysfs(%d)\n",
+					br_sysfs->name, err);
+			br_sysfs++;
+		}
+	}
+}
diff -Naur null/fs/aufs/sysrq.c linux-5.7/fs/aufs/sysrq.c
--- /dev/null
+++ linux-5.7/fs/aufs/sysrq.c	2020-08-22 11:57:41.471782894 +0200
@@ -0,0 +1,149 @@
+// 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/>.
+ */
+
+/*
+ * magic sysrq handler
+ */
+
+/* #include <linux/sysrq.h> */
+#include <linux/writeback.h>
+#include "aufs.h"
+
+/* ---------------------------------------------------------------------- */
+
+static void sysrq_sb(struct super_block *sb)
+{
+	char *plevel;
+	struct au_sbinfo *sbinfo;
+	struct file *file;
+	struct hlist_bl_head *files;
+	struct hlist_bl_node *pos;
+	struct au_finfo *finfo;
+	struct inode *i;
+
+	plevel = au_plevel;
+	au_plevel = KERN_WARNING;
+
+	/* since we define pr_fmt, call printk directly */
+#define pr(str) printk(KERN_WARNING AUFS_NAME ": " str)
+
+	sbinfo = au_sbi(sb);
+	printk(KERN_WARNING "si=%lx\n", sysaufs_si_id(sbinfo));
+	pr("superblock\n");
+	au_dpri_sb(sb);
+
+#if 0 /* reserved */
+	do {
+		int err, i, j, ndentry;
+		struct au_dcsub_pages dpages;
+		struct au_dpage *dpage;
+
+		err = au_dpages_init(&dpages, GFP_ATOMIC);
+		if (unlikely(err))
+			break;
+		err = au_dcsub_pages(&dpages, sb->s_root, NULL, NULL);
+		if (!err)
+			for (i = 0; i < dpages.ndpage; i++) {
+				dpage = dpages.dpages + i;
+				ndentry = dpage->ndentry;
+				for (j = 0; j < ndentry; j++)
+					au_dpri_dentry(dpage->dentries[j]);
+			}
+		au_dpages_free(&dpages);
+	} while (0);
+#endif
+
+	pr("isolated inode\n");
+	spin_lock(&sb->s_inode_list_lock);
+	list_for_each_entry(i, &sb->s_inodes, i_sb_list) {
+		spin_lock(&i->i_lock);
+		if (hlist_empty(&i->i_dentry))
+			au_dpri_inode(i);
+		spin_unlock(&i->i_lock);
+	}
+	spin_unlock(&sb->s_inode_list_lock);
+
+	pr("files\n");
+	files = &au_sbi(sb)->si_files;
+	hlist_bl_lock(files);
+	hlist_bl_for_each_entry(finfo, pos, files, fi_hlist) {
+		umode_t mode;
+
+		file = finfo->fi_file;
+		mode = file_inode(file)->i_mode;
+		if (!special_file(mode))
+			au_dpri_file(file);
+	}
+	hlist_bl_unlock(files);
+	pr("done\n");
+
+#undef pr
+	au_plevel = plevel;
+}
+
+/* ---------------------------------------------------------------------- */
+
+/* module parameter */
+static char *aufs_sysrq_key = "a";
+module_param_named(sysrq, aufs_sysrq_key, charp, 0444);
+MODULE_PARM_DESC(sysrq, "MagicSysRq key for " AUFS_NAME);
+
+static void au_sysrq(int key __maybe_unused)
+{
+	struct au_sbinfo *sbinfo;
+	struct hlist_bl_node *pos;
+
+	lockdep_off();
+	au_sbilist_lock();
+	hlist_bl_for_each_entry(sbinfo, pos, &au_sbilist, si_list)
+		sysrq_sb(sbinfo->si_sb);
+	au_sbilist_unlock();
+	lockdep_on();
+}
+
+static struct sysrq_key_op au_sysrq_op = {
+	.handler	= au_sysrq,
+	.help_msg	= "Aufs",
+	.action_msg	= "Aufs",
+	.enable_mask	= SYSRQ_ENABLE_DUMP
+};
+
+/* ---------------------------------------------------------------------- */
+
+int __init au_sysrq_init(void)
+{
+	int err;
+	char key;
+
+	err = -1;
+	key = *aufs_sysrq_key;
+	if ('a' <= key && key <= 'z')
+		err = register_sysrq_key(key, &au_sysrq_op);
+	if (unlikely(err))
+		pr_err("err %d, sysrq=%c\n", err, key);
+	return err;
+}
+
+void au_sysrq_fin(void)
+{
+	int err;
+
+	err = unregister_sysrq_key(*aufs_sysrq_key, &au_sysrq_op);
+	if (unlikely(err))
+		pr_err("err %d (ignored)\n", err);
+}
diff -Naur null/fs/aufs/vdir.c linux-5.7/fs/aufs/vdir.c
--- /dev/null
+++ linux-5.7/fs/aufs/vdir.c	2020-08-22 11:57:41.471782894 +0200
@@ -0,0 +1,896 @@
+// 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/>.
+ */
+
+/*
+ * virtual or vertical directory
+ */
+
+#include <linux/iversion.h>
+#include "aufs.h"
+
+static unsigned int calc_size(int nlen)
+{
+	return ALIGN(sizeof(struct au_vdir_de) + nlen, sizeof(ino_t));
+}
+
+static int set_deblk_end(union au_vdir_deblk_p *p,
+			 union au_vdir_deblk_p *deblk_end)
+{
+	if (calc_size(0) <= deblk_end->deblk - p->deblk) {
+		p->de->de_str.len = 0;
+		/* smp_mb(); */
+		return 0;
+	}
+	return -1; /* error */
+}
+
+/* returns true or false */
+static int is_deblk_end(union au_vdir_deblk_p *p,
+			union au_vdir_deblk_p *deblk_end)
+{
+	if (calc_size(0) <= deblk_end->deblk - p->deblk)
+		return !p->de->de_str.len;
+	return 1;
+}
+
+static unsigned char *last_deblk(struct au_vdir *vdir)
+{
+	return vdir->vd_deblk[vdir->vd_nblk - 1];
+}
+
+/* ---------------------------------------------------------------------- */
+
+/* estimate the appropriate size for name hash table */
+unsigned int au_rdhash_est(loff_t sz)
+{
+	unsigned int n;
+
+	n = UINT_MAX;
+	sz >>= 10;
+	if (sz < n)
+		n = sz;
+	if (sz < AUFS_RDHASH_DEF)
+		n = AUFS_RDHASH_DEF;
+	/* pr_info("n %u\n", n); */
+	return n;
+}
+
+/*
+ * the allocated memory has to be freed by
+ * au_nhash_wh_free() or au_nhash_de_free().
+ */
+int au_nhash_alloc(struct au_nhash *nhash, unsigned int num_hash, gfp_t gfp)
+{
+	struct hlist_head *head;
+	unsigned int u;
+	size_t sz;
+
+	sz = sizeof(*nhash->nh_head) * num_hash;
+	head = kmalloc(sz, gfp);
+	if (head) {
+		nhash->nh_num = num_hash;
+		nhash->nh_head = head;
+		for (u = 0; u < num_hash; u++)
+			INIT_HLIST_HEAD(head++);
+		return 0; /* success */
+	}
+
+	return -ENOMEM;
+}
+
+static void nhash_count(struct hlist_head *head)
+{
+#if 0 /* debugging */
+	unsigned long n;
+	struct hlist_node *pos;
+
+	n = 0;
+	hlist_for_each(pos, head)
+		n++;
+	pr_info("%lu\n", n);
+#endif
+}
+
+static void au_nhash_wh_do_free(struct hlist_head *head)
+{
+	struct au_vdir_wh *pos;
+	struct hlist_node *node;
+
+	hlist_for_each_entry_safe(pos, node, head, wh_hash)
+		au_kfree_rcu(pos);
+}
+
+static void au_nhash_de_do_free(struct hlist_head *head)
+{
+	struct au_vdir_dehstr *pos;
+	struct hlist_node *node;
+
+	hlist_for_each_entry_safe(pos, node, head, hash)
+		au_cache_free_vdir_dehstr(pos);
+}
+
+static void au_nhash_do_free(struct au_nhash *nhash,
+			     void (*free)(struct hlist_head *head))
+{
+	unsigned int n;
+	struct hlist_head *head;
+
+	n = nhash->nh_num;
+	if (!n)
+		return;
+
+	head = nhash->nh_head;
+	while (n-- > 0) {
+		nhash_count(head);
+		free(head++);
+	}
+	au_kfree_try_rcu(nhash->nh_head);
+}
+
+void au_nhash_wh_free(struct au_nhash *whlist)
+{
+	au_nhash_do_free(whlist, au_nhash_wh_do_free);
+}
+
+static void au_nhash_de_free(struct au_nhash *delist)
+{
+	au_nhash_do_free(delist, au_nhash_de_do_free);
+}
+
+/* ---------------------------------------------------------------------- */
+
+int au_nhash_test_longer_wh(struct au_nhash *whlist, aufs_bindex_t btgt,
+			    int limit)
+{
+	int num;
+	unsigned int u, n;
+	struct hlist_head *head;
+	struct au_vdir_wh *pos;
+
+	num = 0;
+	n = whlist->nh_num;
+	head = whlist->nh_head;
+	for (u = 0; u < n; u++, head++)
+		hlist_for_each_entry(pos, head, wh_hash)
+			if (pos->wh_bindex == btgt && ++num > limit)
+				return 1;
+	return 0;
+}
+
+static struct hlist_head *au_name_hash(struct au_nhash *nhash,
+				       unsigned char *name,
+				       unsigned int len)
+{
+	unsigned int v;
+	/* const unsigned int magic_bit = 12; */
+
+	AuDebugOn(!nhash->nh_num || !nhash->nh_head);
+
+	v = 0;
+	if (len > 8)
+		len = 8;
+	while (len--)
+		v += *name++;
+	/* v = hash_long(v, magic_bit); */
+	v %= nhash->nh_num;
+	return nhash->nh_head + v;
+}
+
+static int au_nhash_test_name(struct au_vdir_destr *str, const char *name,
+			      int nlen)
+{
+	return str->len == nlen && !memcmp(str->name, name, nlen);
+}
+
+/* returns found or not */
+int au_nhash_test_known_wh(struct au_nhash *whlist, char *name, int nlen)
+{
+	struct hlist_head *head;
+	struct au_vdir_wh *pos;
+	struct au_vdir_destr *str;
+
+	head = au_name_hash(whlist, name, nlen);
+	hlist_for_each_entry(pos, head, wh_hash) {
+		str = &pos->wh_str;
+		AuDbg("%.*s\n", str->len, str->name);
+		if (au_nhash_test_name(str, name, nlen))
+			return 1;
+	}
+	return 0;
+}
+
+/* returns found(true) or not */
+static int test_known(struct au_nhash *delist, char *name, int nlen)
+{
+	struct hlist_head *head;
+	struct au_vdir_dehstr *pos;
+	struct au_vdir_destr *str;
+
+	head = au_name_hash(delist, name, nlen);
+	hlist_for_each_entry(pos, head, hash) {