/*
   * f2fs IO tracer
   *
   * Copyright (c) 2014 Motorola Mobility
   * Copyright (c) 2014 Jaegeuk Kim <jaegeuk@kernel.org>
   *
   * This program is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License version 2 as
   * published by the Free Software Foundation.
   */
  #include <linux/fs.h>
  #include <linux/f2fs_fs.h>
  #include <linux/sched.h>

  #include <linux/radix-tree.h>

  
  #include "f2fs.h"
  #include "trace.h"

  static RADIX_TREE(pids, GFP_ATOMIC);

  static spinlock_t pids_lock;

  static struct last_io_info last_io;

  
  static inline void __print_last_io(void)
  {
  	if (!last_io.len)
  		return;

  	trace_printk("%3x:%3x %4x %-16s %2x %5x %5x %12x %4x
  ",

  			last_io.major, last_io.minor,
  			last_io.pid, "----------------",
  			last_io.type,

  			last_io.fio.op, last_io.fio.op_flags,

  			last_io.fio.new_blkaddr,

  			last_io.len);
  	memset(&last_io, 0, sizeof(last_io));
  }
  
  static int __file_type(struct inode *inode, pid_t pid)
  {
  	if (f2fs_is_atomic_file(inode))
  		return __ATOMIC_FILE;
  	else if (f2fs_is_volatile_file(inode))
  		return __VOLATILE_FILE;
  	else if (S_ISDIR(inode->i_mode))
  		return __DIR_FILE;
  	else if (inode->i_ino == F2FS_NODE_INO(F2FS_I_SB(inode)))
  		return __NODE_FILE;
  	else if (inode->i_ino == F2FS_META_INO(F2FS_I_SB(inode)))
  		return __META_FILE;
  	else if (pid)
  		return __NORMAL_FILE;
  	else
  		return __MISC_FILE;
  }

  void f2fs_trace_pid(struct page *page)
  {

  	struct inode *inode = page->mapping->host;
  	pid_t pid = task_pid_nr(current);
  	void *p;

  	set_page_private(page, (unsigned long)pid);

  	if (radix_tree_preload(GFP_NOFS))
  		return;
  
  	spin_lock(&pids_lock);

  	p = radix_tree_lookup(&pids, pid);
  	if (p == current)

  		goto out;

  	if (p)
  		radix_tree_delete(&pids, pid);
  
  	f2fs_radix_tree_insert(&pids, pid, current);
  
  	trace_printk("%3x:%3x %4x %-16s
  ",
  			MAJOR(inode->i_sb->s_dev), MINOR(inode->i_sb->s_dev),
  			pid, current->comm);

  out:
  	spin_unlock(&pids_lock);
  	radix_tree_preload_end();

  }

  void f2fs_trace_ios(struct f2fs_io_info *fio, int flush)

  {

  	struct inode *inode;
  	pid_t pid;
  	int major, minor;
  
  	if (flush) {
  		__print_last_io();
  		return;
  	}

  	inode = fio->page->mapping->host;
  	pid = page_private(fio->page);

  
  	major = MAJOR(inode->i_sb->s_dev);
  	minor = MINOR(inode->i_sb->s_dev);
  
  	if (last_io.major == major && last_io.minor == minor &&
  			last_io.pid == pid &&
  			last_io.type == __file_type(inode, pid) &&

  			last_io.fio.op == fio->op &&
  			last_io.fio.op_flags == fio->op_flags &&

  			last_io.fio.new_blkaddr + last_io.len ==
  							fio->new_blkaddr) {

  		last_io.len++;
  		return;
  	}
  
  	__print_last_io();
  
  	last_io.major = major;
  	last_io.minor = minor;
  	last_io.pid = pid;
  	last_io.type = __file_type(inode, pid);
  	last_io.fio = *fio;
  	last_io.len = 1;
  	return;

  }

  
  void f2fs_build_trace_ios(void)
  {
  	spin_lock_init(&pids_lock);
  }

  
  #define PIDVEC_SIZE	128
  static unsigned int gang_lookup_pids(pid_t *results, unsigned long first_index,
  							unsigned int max_items)
  {
  	struct radix_tree_iter iter;
  	void **slot;
  	unsigned int ret = 0;
  
  	if (unlikely(!max_items))
  		return 0;
  
  	radix_tree_for_each_slot(slot, &pids, &iter, first_index) {
  		results[ret] = iter.index;

  		if (++ret == max_items)

  			break;
  	}
  	return ret;
  }
  
  void f2fs_destroy_trace_ios(void)
  {
  	pid_t pid[PIDVEC_SIZE];
  	pid_t next_pid = 0;
  	unsigned int found;
  
  	spin_lock(&pids_lock);
  	while ((found = gang_lookup_pids(pid, next_pid, PIDVEC_SIZE))) {
  		unsigned idx;
  
  		next_pid = pid[found - 1] + 1;
  		for (idx = 0; idx < found; idx++)
  			radix_tree_delete(&pids, pid[idx]);
  	}
  	spin_unlock(&pids_lock);
  }