aufs: debugfs interface

Aufs provides some info via debugfs such as
- the branch path
- the current number of pseudo-links
- the size and the number of consumed blocks by XINO, XIB and XIGEN.
Signed-off-by: J. R. Okajima <hooanon05g@gmail.com>

Documentation/ABI/testing/debugfs-aufs

+What:		/debug/aufs/si_<id>/
+Date:		March 2009
+Contact:	J. R. Okajima <hooanon05g@gmail.com>
+Description:
+		Under /debug/aufs, a directory named si_<id> is created
+		per aufs mount, where <id> is a unique id generated
+		internally.
+
+What:		/debug/aufs/si_<id>/plink
+Date:		Apr 2013
+Contact:	J. R. Okajima <hooanon05g@gmail.com>
+Description:
+		It has three lines and shows the information about the
+		pseudo-link. The first line is a single number
+		representing a number of buckets. The second line is a
+		number of pseudo-links per buckets (separated by a
+		blank). The last line is a single number representing a
+		total number of psedo-links.
+		When the aufs mount option 'noplink' is specified, it
+		will show "1\n0\n0\n".
+
+What:		/debug/aufs/si_<id>/xib
+Date:		March 2009
+Contact:	J. R. Okajima <hooanon05g@gmail.com>
+Description:
+		It shows the consumed blocks by xib (External Inode Number
+		Bitmap), its block size and file size.
+		When the aufs mount option 'noxino' is specified, it
+		will be empty. About XINO files, see the aufs manual.
+
+What:		/debug/aufs/si_<id>/xi0, xi1 ... xiN and xiN-N
+Date:		March 2009
+Contact:	J. R. Okajima <hooanon05g@gmail.com>
+Description:
+		It shows the consumed blocks by xino (External Inode Number
+		Translation Table), its link count, block size and file
+		size.
+		Due to the file size limit, there may exist multiple
+		xino files per branch.  In this case, "-N" is added to
+		the filename and it corresponds to the index of the
+		internal xino array.  "-0" is omitted.
+		When the aufs mount option 'noxino' is specified, Those
+		entries won't exist.  About XINO files, see the aufs
+		manual.
+
+What:		/debug/aufs/si_<id>/xigen
+Date:		March 2009
+Contact:	J. R. Okajima <hooanon05g@gmail.com>
+Description:
+		It shows the consumed blocks by xigen (External Inode
+		Generation Table), its block size and file size.
+		If CONFIG_AUFS_EXPORT is disabled, this entry will not
+		be created.
+		When the aufs mount option 'noxino' is specified, it
+		will be empty. About XINO files, see the aufs manual.

fs/aufs/Makefile

@@ -22,6 +22,7 @@ aufs-y := module.o sbinfo.o super.o branch.o xino.o sysaufs.o opts.o \
 # all are boolean
 aufs-$(CONFIG_PROC_FS) += procfs.o plink.o
 aufs-$(CONFIG_SYSFS) += sysfs.o
+aufs-$(CONFIG_DEBUG_FS) += dbgaufs.o
 aufs-$(CONFIG_AUFS_HNOTIFY) += hnotify.o
 aufs-$(CONFIG_AUFS_HFSNOTIFY) += hfsnotify.o
 aufs-$(CONFIG_AUFS_EXPORT) += export.o

fs/aufs/aufs.h

@@ -25,6 +25,7 @@
 #include "branch.h"
 #include "cpup.h"
 #include "dcsub.h"
+#include "dbgaufs.h"
 #include "dentry.h"
 #include "dir.h"
 #include "dirren.h"

fs/aufs/branch.c

@@ -511,6 +511,7 @@ int au_br_add(struct super_block *sb, struct au_opt_add *add, int remount)
 	sysaufs_brs_del(sb, add_bindex);	/* remove successors */
 	au_br_do_add(sb, add_branch, add_bindex);
 	sysaufs_brs_add(sb, add_bindex);	/* append successors */
+	dbgaufs_brs_add(sb, add_bindex, /*topdown*/0);	/* rename successors */
 
 	h_dentry = add->path.dentry;
 	if (!add_bindex) {
@@ -1054,8 +1055,10 @@ int au_br_del(struct super_block *sb, struct au_opt_del *del, int remount)
 	}
 
 	sysaufs_brs_del(sb, bindex);	/* remove successors */
+	dbgaufs_xino_del(br);		/* remove one */
 	au_br_do_del(sb, bindex, br);
 	sysaufs_brs_add(sb, bindex);	/* append successors */
+	dbgaufs_brs_add(sb, bindex, /*topdown*/1);	/* rename successors */
 
 	if (!bindex) {
 		au_cpup_attr_all(d_inode(root), /*force*/1);

fs/aufs/branch.h

@@ -103,6 +103,10 @@ struct au_branch {
 	struct au_brsysfs	br_sysfs[AuBrSysfs_Last];
 #endif
 
+#ifdef CONFIG_DEBUG_FS
+	struct dentry		 *br_dbgaufs; /* xino */
+#endif
+
 	struct au_dr_br		br_dirren;
 };
 

fs/aufs/dbgaufs.c

+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2005-2019 Junjiro R. Okajima
+ */
+
+/*
+ * debugfs interface
+ */
+
+#include <linux/debugfs.h>
+#include "aufs.h"
+
+#ifndef CONFIG_SYSFS
+#error DEBUG_FS depends upon SYSFS
+#endif
+
+static struct dentry *dbgaufs;
+static const mode_t dbgaufs_mode = 0444;
+
+/* 20 is max digits length of ulong 64 */
+struct dbgaufs_arg {
+	int n;
+	char a[20 * 4];
+};
+
+/*
+ * common function for all XINO files
+ */
+static int dbgaufs_xi_release(struct inode *inode __maybe_unused,
+			      struct file *file)
+{
+	void *p;
+
+	p = file->private_data;
+	if (p) {
+		/* this is struct dbgaufs_arg */
+		AuDebugOn(!au_kfree_sz_test(p));
+		au_kfree_do_rcu(p);
+	}
+	return 0;
+}
+
+static int dbgaufs_xi_open(struct file *xf, struct file *file, int do_fcnt,
+			   int cnt)
+{
+	int err;
+	struct kstat st;
+	struct dbgaufs_arg *p;
+
+	err = -ENOMEM;
+	p = kmalloc(sizeof(*p), GFP_NOFS);
+	if (unlikely(!p))
+		goto out;
+
+	err = 0;
+	p->n = 0;
+	file->private_data = p;
+	if (!xf)
+		goto out;
+
+	err = vfsub_getattr(&xf->f_path, &st);
+	if (!err) {
+		if (do_fcnt)
+			p->n = snprintf
+				(p->a, sizeof(p->a), "%d, %llux%u %lld\n",
+				 cnt, st.blocks, st.blksize,
+				 (long long)st.size);
+		else
+			p->n = snprintf(p->a, sizeof(p->a), "%llux%u %lld\n",
+					st.blocks, st.blksize,
+					(long long)st.size);
+		AuDebugOn(p->n >= sizeof(p->a));
+	} else {
+		p->n = snprintf(p->a, sizeof(p->a), "err %d\n", err);
+		err = 0;
+	}
+
+out:
+	return err;
+}
+
+static ssize_t dbgaufs_xi_read(struct file *file, char __user *buf,
+			       size_t count, loff_t *ppos)
+{
+	struct dbgaufs_arg *p;
+
+	p = file->private_data;
+	return simple_read_from_buffer(buf, count, ppos, p->a, p->n);
+}
+
+/* ---------------------------------------------------------------------- */
+
+struct dbgaufs_plink_arg {
+	int n;
+	char a[];
+};
+
+static int dbgaufs_plink_release(struct inode *inode __maybe_unused,
+				 struct file *file)
+{
+	free_page((unsigned long)file->private_data);
+	return 0;
+}
+
+static int dbgaufs_plink_open(struct inode *inode, struct file *file)
+{
+	int err, i, limit;
+	unsigned long n, sum;
+	struct dbgaufs_plink_arg *p;
+	struct au_sbinfo *sbinfo;
+	struct super_block *sb;
+	struct hlist_bl_head *hbl;
+
+	err = -ENOMEM;
+	p = (void *)get_zeroed_page(GFP_NOFS);
+	if (unlikely(!p))
+		goto out;
+
+	err = -EFBIG;
+	sbinfo = inode->i_private;
+	sb = sbinfo->si_sb;
+	si_noflush_read_lock(sb);
+	if (au_opt_test(au_mntflags(sb), PLINK)) {
+		limit = PAGE_SIZE - sizeof(p->n);
+
+		/* the number of buckets */
+		n = snprintf(p->a + p->n, limit, "%d\n", AuPlink_NHASH);
+		p->n += n;
+		limit -= n;
+
+		sum = 0;
+		for (i = 0, hbl = sbinfo->si_plink; i < AuPlink_NHASH;
+		     i++, hbl++) {
+			n = au_hbl_count(hbl);
+			sum += n;
+
+			n = snprintf(p->a + p->n, limit, "%lu ", n);
+			p->n += n;
+			limit -= n;
+			if (unlikely(limit <= 0))
+				goto out_free;
+		}
+		p->a[p->n - 1] = '\n';
+
+		/* the sum of plinks */
+		n = snprintf(p->a + p->n, limit, "%lu\n", sum);
+		p->n += n;
+		limit -= n;
+		if (unlikely(limit <= 0))
+			goto out_free;
+	} else {
+#define str "1\n0\n0\n"
+		p->n = sizeof(str) - 1;
+		strcpy(p->a, str);
+#undef str
+	}
+	si_read_unlock(sb);
+
+	err = 0;
+	file->private_data = p;
+	goto out; /* success */
+
+out_free:
+	free_page((unsigned long)p);
+out:
+	return err;
+}
+
+static ssize_t dbgaufs_plink_read(struct file *file, char __user *buf,
+				  size_t count, loff_t *ppos)
+{
+	struct dbgaufs_plink_arg *p;
+
+	p = file->private_data;
+	return simple_read_from_buffer(buf, count, ppos, p->a, p->n);
+}
+
+static const struct file_operations dbgaufs_plink_fop = {
+	.owner		= THIS_MODULE,
+	.open		= dbgaufs_plink_open,
+	.release	= dbgaufs_plink_release,
+	.read		= dbgaufs_plink_read
+};
+
+/* ---------------------------------------------------------------------- */
+
+static int dbgaufs_xib_open(struct inode *inode, struct file *file)
+{
+	int err;
+	struct au_sbinfo *sbinfo;
+	struct super_block *sb;
+
+	sbinfo = inode->i_private;
+	sb = sbinfo->si_sb;
+	si_noflush_read_lock(sb);
+	err = dbgaufs_xi_open(sbinfo->si_xib, file, /*do_fcnt*/0, /*cnt*/0);
+	si_read_unlock(sb);
+	return err;
+}
+
+static const struct file_operations dbgaufs_xib_fop = {
+	.owner		= THIS_MODULE,
+	.open		= dbgaufs_xib_open,
+	.release	= dbgaufs_xi_release,
+	.read		= dbgaufs_xi_read
+};
+
+/* ---------------------------------------------------------------------- */
+
+#define DbgaufsXi_PREFIX "xi"
+
+static int dbgaufs_xino_open(struct inode *inode, struct file *file)
+{
+	int err, idx;
+	long l;
+	aufs_bindex_t bindex;
+	char *p, a[sizeof(DbgaufsXi_PREFIX) + 8];
+	struct au_sbinfo *sbinfo;
+	struct super_block *sb;
+	struct au_xino *xi;
+	struct file *xf;
+	struct qstr *name;
+	struct au_branch *br;
+
+	err = -ENOENT;
+	name = &file->f_path.dentry->d_name;
+	if (unlikely(name->len < sizeof(DbgaufsXi_PREFIX)
+		     || memcmp(name->name, DbgaufsXi_PREFIX,
+			       sizeof(DbgaufsXi_PREFIX) - 1)))
+		goto out;
+
+	AuDebugOn(name->len >= sizeof(a));
+	memcpy(a, name->name, name->len);
+	a[name->len] = '\0';
+	p = strchr(a, '-');
+	if (p)
+		*p = '\0';
+	err = kstrtol(a + sizeof(DbgaufsXi_PREFIX) - 1, 10, &l);
+	if (unlikely(err))
+		goto out;
+	bindex = l;
+	idx = 0;
+	if (p) {
+		err = kstrtol(p + 1, 10, &l);
+		if (unlikely(err))
+			goto out;
+		idx = l;
+	}
+
+	err = -ENOENT;
+	sbinfo = inode->i_private;
+	sb = sbinfo->si_sb;
+	si_noflush_read_lock(sb);
+	if (unlikely(bindex < 0 || bindex > au_sbbot(sb)))
+		goto out_si;
+	br = au_sbr(sb, bindex);
+	xi = br->br_xino;
+	if (unlikely(idx >= xi->xi_nfile))
+		goto out_si;
+	xf = au_xino_file(xi, idx);
+	if (xf)
+		err = dbgaufs_xi_open(xf, file, /*do_fcnt*/1,
+				      au_xino_count(br));
+
+out_si:
+	si_read_unlock(sb);
+out:
+	AuTraceErr(err);
+	return err;
+}
+
+static const struct file_operations dbgaufs_xino_fop = {
+	.owner		= THIS_MODULE,
+	.open		= dbgaufs_xino_open,
+	.release	= dbgaufs_xi_release,
+	.read		= dbgaufs_xi_read
+};
+
+void dbgaufs_xino_del(struct au_branch *br)
+{
+	struct dentry *dbgaufs;
+
+	dbgaufs = br->br_dbgaufs;
+	if (!dbgaufs)
+		return;
+
+	br->br_dbgaufs = NULL;
+	/* debugfs acquires the parent i_mutex */
+	lockdep_off();
+	debugfs_remove(dbgaufs);
+	lockdep_on();
+}
+
+void dbgaufs_brs_del(struct super_block *sb, aufs_bindex_t bindex)
+{
+	aufs_bindex_t bbot;
+	struct au_branch *br;
+
+	if (!au_sbi(sb)->si_dbgaufs)
+		return;
+
+	bbot = au_sbbot(sb);
+	for (; bindex <= bbot; bindex++) {
+		br = au_sbr(sb, bindex);
+		dbgaufs_xino_del(br);
+	}
+}
+
+static void dbgaufs_br_do_add(struct super_block *sb, aufs_bindex_t bindex,
+			      unsigned int idx, struct dentry *parent,
+			      struct au_sbinfo *sbinfo)
+{
+	struct au_branch *br;
+	struct dentry *d;
+	/* "xi" bindex(5) "-" idx(2) NULL */
+	char name[sizeof(DbgaufsXi_PREFIX) + 8];
+
+	if (!idx)
+		snprintf(name, sizeof(name), DbgaufsXi_PREFIX "%d", bindex);
+	else
+		snprintf(name, sizeof(name), DbgaufsXi_PREFIX "%d-%u",
+			 bindex, idx);
+	br = au_sbr(sb, bindex);
+	if (br->br_dbgaufs) {
+		struct qstr qstr = QSTR_INIT(name, strlen(name));
+
+		if (!au_qstreq(&br->br_dbgaufs->d_name, &qstr)) {
+			/* debugfs acquires the parent i_mutex */
+			lockdep_off();
+			d = debugfs_rename(parent, br->br_dbgaufs, parent,
+					   name);
+			lockdep_on();
+			if (unlikely(!d))
+				pr_warn("failed renaming %pd/%s, ignored.\n",
+					parent, name);
+		}
+	} else {
+		lockdep_off();
+		br->br_dbgaufs = debugfs_create_file(name, dbgaufs_mode, parent,
+						     sbinfo, &dbgaufs_xino_fop);
+		lockdep_on();
+		if (unlikely(!br->br_dbgaufs))
+			pr_warn("failed creating %pd/%s, ignored.\n",
+				parent, name);
+	}
+}
+
+static void dbgaufs_br_add(struct super_block *sb, aufs_bindex_t bindex,
+			   struct dentry *parent, struct au_sbinfo *sbinfo)
+{
+	struct au_branch *br;
+	struct au_xino *xi;
+	unsigned int u;
+
+	br = au_sbr(sb, bindex);
+	xi = br->br_xino;
+	for (u = 0; u < xi->xi_nfile; u++)
+		dbgaufs_br_do_add(sb, bindex, u, parent, sbinfo);
+}
+
+void dbgaufs_brs_add(struct super_block *sb, aufs_bindex_t bindex, int topdown)
+{
+	struct au_sbinfo *sbinfo;
+	struct dentry *parent;
+	aufs_bindex_t bbot;
+
+	if (!au_opt_test(au_mntflags(sb), XINO))
+		return;
+
+	sbinfo = au_sbi(sb);
+	parent = sbinfo->si_dbgaufs;
+	if (!parent)
+		return;
+
+	bbot = au_sbbot(sb);
+	if (topdown)
+		for (; bindex <= bbot; bindex++)
+			dbgaufs_br_add(sb, bindex, parent, sbinfo);
+	else
+		for (; bbot >= bindex; bbot--)
+			dbgaufs_br_add(sb, bbot, parent, sbinfo);
+}
+
+/* ---------------------------------------------------------------------- */
+
+#ifdef CONFIG_AUFS_EXPORT
+static int dbgaufs_xigen_open(struct inode *inode, struct file *file)
+{
+	int err;
+	struct au_sbinfo *sbinfo;
+	struct super_block *sb;
+
+	sbinfo = inode->i_private;
+	sb = sbinfo->si_sb;
+	si_noflush_read_lock(sb);
+	err = dbgaufs_xi_open(sbinfo->si_xigen, file, /*do_fcnt*/0, /*cnt*/0);
+	si_read_unlock(sb);
+	return err;
+}
+
+static const struct file_operations dbgaufs_xigen_fop = {
+	.owner		= THIS_MODULE,
+	.open		= dbgaufs_xigen_open,
+	.release	= dbgaufs_xi_release,
+	.read		= dbgaufs_xi_read
+};
+
+static int dbgaufs_xigen_init(struct au_sbinfo *sbinfo)
+{
+	int err;
+
+	/*
+	 * This function is a dynamic '__init' function actually,
+	 * so the tiny check for si_rwsem is unnecessary.
+	 */
+	/* AuRwMustWriteLock(&sbinfo->si_rwsem); */
+
+	err = -EIO;
+	sbinfo->si_dbgaufs_xigen = debugfs_create_file
+		("xigen", dbgaufs_mode, sbinfo->si_dbgaufs, sbinfo,
+		 &dbgaufs_xigen_fop);
+	if (sbinfo->si_dbgaufs_xigen)
+		err = 0;
+
+	return err;
+}
+#else
+static int dbgaufs_xigen_init(struct au_sbinfo *sbinfo)
+{
+	return 0;
+}
+#endif /* CONFIG_AUFS_EXPORT */
+
+/* ---------------------------------------------------------------------- */
+
+void dbgaufs_si_fin(struct au_sbinfo *sbinfo)
+{
+	/*
+	 * This function is a dynamic '__fin' function actually,
+	 * so the tiny check for si_rwsem is unnecessary.
+	 */
+	/* AuRwMustWriteLock(&sbinfo->si_rwsem); */
+
+	debugfs_remove_recursive(sbinfo->si_dbgaufs);
+	sbinfo->si_dbgaufs = NULL;
+}
+
+int dbgaufs_si_init(struct au_sbinfo *sbinfo)
+{
+	int err;
+	char name[SysaufsSiNameLen];
+
+	/*
+	 * This function is a dynamic '__init' function actually,
+	 * so the tiny check for si_rwsem is unnecessary.
+	 */
+	/* AuRwMustWriteLock(&sbinfo->si_rwsem); */
+
+	err = -ENOENT;
+	if (!dbgaufs) {
+		AuErr1("/debug/aufs is uninitialized\n");
+		goto out;
+	}
+
+	err = -EIO;
+	sysaufs_name(sbinfo, name);
+	sbinfo->si_dbgaufs = debugfs_create_dir(name, dbgaufs);
+	if (unlikely(!sbinfo->si_dbgaufs))
+		goto out;
+
+	/* regardless plink/noplink option */
+	sbinfo->si_dbgaufs_plink = debugfs_create_file
+		("plink", dbgaufs_mode, sbinfo->si_dbgaufs, sbinfo,
+		 &dbgaufs_plink_fop);
+	if (unlikely(!sbinfo->si_dbgaufs_plink))
+		goto out_dir;
+
+	/* regardless xino/noxino option */
+	sbinfo->si_dbgaufs_xib = debugfs_create_file
+		("xib", dbgaufs_mode, sbinfo->si_dbgaufs, sbinfo,
+		 &dbgaufs_xib_fop);
+	if (unlikely(!sbinfo->si_dbgaufs_xib))
+		goto out_dir;
+
+	err = dbgaufs_xigen_init(sbinfo);
+	if (!err)
+		goto out; /* success */
+
+out_dir:
+	dbgaufs_si_fin(sbinfo);
+out:
+	if (unlikely(err))
+		pr_err("debugfs/aufs failed\n");
+	return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+void dbgaufs_fin(void)
+{
+	debugfs_remove(dbgaufs);
+}
+
+int __init dbgaufs_init(void)
+{
+	int err;
+
+	err = -EIO;
+	dbgaufs = debugfs_create_dir(AUFS_NAME, NULL);
+	if (dbgaufs)
+		err = 0;
+	return err;
+}

fs/aufs/dbgaufs.h

+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2005-2019 Junjiro R. Okajima
+ */
+
+/*
+ * debugfs interface
+ */
+
+#ifndef __DBGAUFS_H__
+#define __DBGAUFS_H__
+
+#ifdef __KERNEL__
+
+struct super_block;
+struct au_sbinfo;
+struct au_branch;
+
+#ifdef CONFIG_DEBUG_FS
+/* dbgaufs.c */
+void dbgaufs_xino_del(struct au_branch *br);
+void dbgaufs_brs_del(struct super_block *sb, aufs_bindex_t bindex);
+void dbgaufs_brs_add(struct super_block *sb, aufs_bindex_t bindex, int topdown);
+void dbgaufs_si_fin(struct au_sbinfo *sbinfo);
+int dbgaufs_si_init(struct au_sbinfo *sbinfo);
+void dbgaufs_fin(void);
+int __init dbgaufs_init(void);
+#else
+AuStubVoid(dbgaufs_xino_del, struct au_branch *br)
+AuStubVoid(dbgaufs_brs_del, struct super_block *sb, aufs_bindex_t bindex)
+AuStubVoid(dbgaufs_brs_add, struct super_block *sb, aufs_bindex_t bindex,
+	   int topdown)
+AuStubVoid(dbgaufs_si_fin, struct au_sbinfo *sbinfo)
+AuStubInt0(dbgaufs_si_init, struct au_sbinfo *sbinfo)
+AuStubVoid(dbgaufs_fin, void)
+AuStubInt0(__init dbgaufs_init, void)
+#endif /* CONFIG_DEBUG_FS */
+
+#endif /* __KERNEL__ */
+#endif /* __DBGAUFS_H__ */

fs/aufs/module.c

@@ -183,9 +183,12 @@ static int __init aufs_init(void)
 	err = sysaufs_init();
 	if (unlikely(err))
 		goto out;
-	err = au_procfs_init();
+	err = dbgaufs_init();
 	if (unlikely(err))
 		goto out_sysaufs;
+	err = au_procfs_init();
+	if (unlikely(err))
+		goto out_dbgaufs;
 	err = au_wkq_init();
 	if (unlikely(err))
 		goto out_procfs;
@@ -212,6 +215,8 @@ out_wkq:
 	au_wkq_fin();
 out_procfs:
 	au_procfs_fin();
+out_dbgaufs:
+	dbgaufs_fin();
 out_sysaufs:
 	sysaufs_fin();
 	au_dy_fin();

fs/aufs/sbinfo.c

@@ -29,6 +29,7 @@ void au_si_free(struct kobject *kobj)
 	AuLCntZero(au_lcnt_read(&sbinfo->si_nfiles, /*do_rev*/0));
 	au_lcnt_fin(&sbinfo->si_nfiles, /*do_sync*/0);
 
+	dbgaufs_si_fin(sbinfo);
 	au_rw_write_lock(&sbinfo->si_rwsem);
 	au_br_free(sbinfo);
 	au_rw_write_unlock(&sbinfo->si_rwsem);
@@ -58,6 +59,12 @@ int au_si_alloc(struct super_block *sb)
 		goto out_sbinfo;
 
 	err = sysaufs_si_init(sbinfo);
+	if (!err) {
+		dbgaufs_si_null(sbinfo);
+		err = dbgaufs_si_init(sbinfo);
+		if (unlikely(err))
+			kobject_put(&sbinfo->si_kobj);
+	}
 	if (unlikely(err))
 		goto out_br;
 

fs/aufs/super.h

@@ -157,6 +157,14 @@ struct au_sbinfo {
 	 * but using sysfs is majority.
 	 */
 	struct kobject		si_kobj;
+#ifdef CONFIG_DEBUG_FS
+	struct dentry		 *si_dbgaufs;
+	struct dentry		 *si_dbgaufs_plink;
+	struct dentry		 *si_dbgaufs_xib;
+#ifdef CONFIG_AUFS_EXPORT
+	struct dentry		 *si_dbgaufs_xigen;
+#endif
+#endif
 
 #ifdef CONFIG_AUFS_SBILIST
 	struct hlist_bl_node	si_list;
@@ -316,6 +324,25 @@ AuStubVoid(au_sbilist_del, struct super_block *sb)
 
 /* ---------------------------------------------------------------------- */
 
+static inline void dbgaufs_si_null(struct au_sbinfo *sbinfo)
+{
+	/*
+	 * This function is a dynamic '__init' function actually,
+	 * so the tiny check for si_rwsem is unnecessary.
+	 */
+	/* AuRwMustWriteLock(&sbinfo->si_rwsem); */
+#ifdef CONFIG_DEBUG_FS
+	sbinfo->si_dbgaufs = NULL;
+	sbinfo->si_dbgaufs_plink = NULL;
+	sbinfo->si_dbgaufs_xib = NULL;
+#ifdef CONFIG_AUFS_EXPORT
+	sbinfo->si_dbgaufs_xigen = NULL;
+#endif
+#endif
+}
+
+/* ---------------------------------------------------------------------- */
+
 /* current->atomic_flags */
 /* this value should never corrupt the ones defined in linux/sched.h */
 #define PFA_AUFS	7

fs/aufs/xino.c

@@ -1558,6 +1558,7 @@ void au_xino_clr(struct super_block *sb)
 	au_xigen_clr(sb);
 	xino_clear_xib(sb);
 	xino_clear_br(sb);
+	dbgaufs_brs_del(sb, 0);
 	sbinfo = au_sbi(sb);
 	/* lvalue, do not call au_mntflags() */
 	au_opt_clr(sbinfo->si_mntflags, XINO);
@@ -1603,8 +1604,10 @@ int au_xino_set(struct super_block *sb, struct au_opt_xino *xiopt, int remount)
 		err = au_xigen_set(sb, path);
 	if (!err)
 		err = au_xino_set_br(sb, path);
-	if (!err)
+	if (!err) {
+		dbgaufs_brs_add(sb, 0, /*topdown*/1);
 		goto out; /* success */
+	}
 
 	/* reset all */
 	AuIOErr("failed setting xino(%d).\n", err);