1 files changed, 526 insertions, 0 deletions
diff --git a/fs/aufs/dbgaufs.c b/fs/aufs/dbgaufs.c
new file mode 100644
index 000000000000..e32d91d1f638
--- /dev/null
+++ b/fs/aufs/dbgaufs.c
@@ -0,0 +1,526 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2005-2019 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/>.
+ */
+
+/*
+ * 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;
+}