UBIFS: switch self-check knobs to debugfs

UBIFS has many built-in self-check functions which can be enabled using the
debug_chks module parameter or the corresponding sysfs file
(/sys/module/ubifs/parameters/debug_chks). However, this is not flexible enough
because it is not per-filesystem. This patch moves this to debugfs interfaces.

We already have debugfs support, so this patch just adds more debugfs files.
While looking at debugfs support I've noticed that it is racy WRT file-system
unmount, and added a TODO entry for that. This problem has been there for long
time and it is quite standard debugfs PITA. The plan is to fix this later.

This patch is simple, but it is large because it changes many places where we
check if a particular type of checks is enabled or disabled.

Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>

1 files changed, 123 insertions, 17 deletions

diff --git a/fs/ubifs/debug.c b/fs/ubifs/debug.c
index a967d68..fdfa5de 100644
--- a/fs/ubifs/debug.c
+++ b/fs/ubifs/debug.c
@@ -31,9 +31,9 @@
 
 #include "ubifs.h"
 #include <linux/module.h>
-#include <linux/moduleparam.h>
 #include <linux/debugfs.h>
 #include <linux/math64.h>
+#include <linux/uaccess.h>
 
 #ifdef CONFIG_UBIFS_FS_DEBUG
 
@@ -42,15 +42,6 @@ DEFINE_SPINLOCK(dbg_lock);
 static char dbg_key_buf0[128];
 static char dbg_key_buf1[128];
 
-unsigned int ubifs_chk_flags;
-unsigned int ubifs_tst_flags;
-
-module_param_named(debug_chks, ubifs_chk_flags, uint, S_IRUGO | S_IWUSR);
-module_param_named(debug_tsts, ubifs_tst_flags, uint, S_IRUGO | S_IWUSR);
-
-MODULE_PARM_DESC(debug_chks, "Debug check flags");
-MODULE_PARM_DESC(debug_tsts, "Debug special test flags");
-
 static const char *get_key_fmt(int fmt)
 {
 	switch (fmt) {
@@ -2886,21 +2877,93 @@ static int open_debugfs_file(struct inode *inode, struct file *file)
 	return nonseekable_open(inode, file);
 }
 
-static ssize_t write_debugfs_file(struct file *file, const char __user *buf,
-				  size_t count, loff_t *ppos)
+static ssize_t dfs_file_read(struct file *file, char __user *u, size_t count,
+			     loff_t *ppos)
+{
+	struct dentry *dent = file->f_path.dentry;
+	struct ubifs_info *c = file->private_data;
+	struct ubifs_debug_info *d = c->dbg;
+	char buf[3];
+	int val;
+
+	if (dent == d->dfs_chk_gen)
+		val = d->chk_gen;
+	else if (dent == d->dfs_chk_index)
+		val = d->chk_index;
+	else if (dent == d->dfs_chk_orph)
+		val = d->chk_orph;
+	else if (dent == d->dfs_chk_lprops)
+		val = d->chk_lprops;
+	else if (dent == d->dfs_chk_fs)
+		val = d->chk_fs;
+	else if (dent == d->dfs_tst_rcvry)
+		val = d->tst_rcvry;
+	else
+		return -EINVAL;
+
+	if (val)
+		buf[0] = '1';
+	else
+		buf[0] = '0';
+	buf[1] = '\n';
+	buf[2] = 0x00;
+
+	return simple_read_from_buffer(u, count, ppos, buf, 2);
+}
+
+static ssize_t dfs_file_write(struct file *file, const char __user *u,
+			      size_t count, loff_t *ppos)
 {
 	struct ubifs_info *c = file->private_data;
 	struct ubifs_debug_info *d = c->dbg;
+	struct dentry *dent = file->f_path.dentry;
+	size_t buf_size;
+	char buf[8];
+	int val;
 
-	if (file->f_path.dentry == d->dfs_dump_lprops)
+	/*
+	 * FIXME: this is racy - the file-system might have already been
+	 * unmounted and we'd oops in this case.
+	 */
+	if (file->f_path.dentry == d->dfs_dump_lprops) {
 		dbg_dump_lprops(c);
-	else if (file->f_path.dentry == d->dfs_dump_budg)
+		return count;
+	}
+	if (file->f_path.dentry == d->dfs_dump_budg) {
 		dbg_dump_budg(c, &c->bi);
-	else if (file->f_path.dentry == d->dfs_dump_tnc) {
+		return count;
+	}
+	if (file->f_path.dentry == d->dfs_dump_tnc) {
 		mutex_lock(&c->tnc_mutex);
 		dbg_dump_tnc(c);
 		mutex_unlock(&c->tnc_mutex);
-	} else
+		return count;
+	}
+
+	buf_size = min_t(size_t, count, (sizeof(buf) - 1));
+	if (copy_from_user(buf, u, buf_size))
+		return -EFAULT;
+
+	if (buf[0] == '1')
+		val = 1;
+	else if (buf[0] == '0')
+		val = 0;
+	else
+		return -EINVAL;
+
+	if (dent == d->dfs_chk_gen)
+		d->chk_gen = val;
+	else if (dent == d->dfs_chk_index)
+		d->chk_index = val;
+	else if (dent == d->dfs_chk_orph)
+		d->chk_orph = val;
+	else if (dent == d->dfs_chk_lprops)
+		d->chk_lprops = val;
+	else if (dent == d->dfs_chk_fs)
+		d->chk_fs = val;
+	else if (dent == d->dfs_tst_rcvry)
+		d->tst_rcvry = val;
+	else
 		return -EINVAL;
 
 	return count;
@@ -2908,7 +2971,8 @@ static ssize_t write_debugfs_file(struct file *file, const char __user *buf,
 
 static const struct file_operations dfs_fops = {
 	.open = open_debugfs_file,
-	.write = write_debugfs_file,
+	.read = dfs_file_read,
+	.write = dfs_file_write,
 	.owner = THIS_MODULE,
 	.llseek = no_llseek,
 };
@@ -2965,6 +3029,48 @@ int dbg_debugfs_init_fs(struct ubifs_info *c)
 		goto out_remove;
 	d->dfs_dump_tnc = dent;
 
+	fname = "chk_general";
+	dent = debugfs_create_file(fname, S_IRUSR | S_IWUSR, d->dfs_dir, c,
+				   &dfs_fops);
+	if (IS_ERR_OR_NULL(dent))
+		goto out_remove;
+	d->dfs_chk_gen = dent;
+
+	fname = "chk_index";
+	dent = debugfs_create_file(fname, S_IRUSR | S_IWUSR, d->dfs_dir, c,
+				   &dfs_fops);
+	if (IS_ERR_OR_NULL(dent))
+		goto out_remove;
+	d->dfs_chk_index = dent;
+
+	fname = "chk_orphans";
+	dent = debugfs_create_file(fname, S_IRUSR | S_IWUSR, d->dfs_dir, c,
+				   &dfs_fops);
+	if (IS_ERR_OR_NULL(dent))
+		goto out_remove;
+	d->dfs_chk_orph = dent;
+
+	fname = "chk_lprops";
+	dent = debugfs_create_file(fname, S_IRUSR | S_IWUSR, d->dfs_dir, c,
+				   &dfs_fops);
+	if (IS_ERR_OR_NULL(dent))
+		goto out_remove;
+	d->dfs_chk_lprops = dent;
+
+	fname = "chk_fs";
+	dent = debugfs_create_file(fname, S_IRUSR | S_IWUSR, d->dfs_dir, c,
+				   &dfs_fops);
+	if (IS_ERR_OR_NULL(dent))
+		goto out_remove;
+	d->dfs_chk_fs = dent;
+
+	fname = "tst_recovery";
+	dent = debugfs_create_file(fname, S_IRUSR | S_IWUSR, d->dfs_dir, c,
+				   &dfs_fops);
+	if (IS_ERR_OR_NULL(dent))
+		goto out_remove;
+	d->dfs_tst_rcvry = dent;
+
 	return 0;
 
 out_remove: