/*
   * dat.c - NILFS disk address translation.
   *
   * Copyright (C) 2006-2008 Nippon Telegraph and Telephone Corporation.
   *
   * This program 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, write to the Free Software
   * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
   *
   * Written by Koji Sato <koji@osrg.net>.
   */
  
  #include <linux/types.h>
  #include <linux/buffer_head.h>
  #include <linux/string.h>
  #include <linux/errno.h>
  #include "nilfs.h"
  #include "mdt.h"
  #include "alloc.h"
  #include "dat.h"
  
  
  #define NILFS_CNO_MIN	((__u64)1)
  #define NILFS_CNO_MAX	(~(__u64)0)

  /**
   * struct nilfs_dat_info - on-memory private data of DAT file
   * @mi: on-memory private data of metadata file
   * @palloc_cache: persistent object allocator cache of DAT file
   * @shadow: shadow map of DAT file
   */

  struct nilfs_dat_info {
  	struct nilfs_mdt_info mi;
  	struct nilfs_palloc_cache palloc_cache;

  	struct nilfs_shadow_map shadow;

  };
  
  static inline struct nilfs_dat_info *NILFS_DAT_I(struct inode *dat)
  {
  	return (struct nilfs_dat_info *)NILFS_MDT(dat);
  }

  static int nilfs_dat_prepare_entry(struct inode *dat,
  				   struct nilfs_palloc_req *req, int create)
  {
  	return nilfs_palloc_get_entry_block(dat, req->pr_entry_nr,
  					    create, &req->pr_entry_bh);
  }
  
  static void nilfs_dat_commit_entry(struct inode *dat,
  				   struct nilfs_palloc_req *req)
  {

  	mark_buffer_dirty(req->pr_entry_bh);

  	nilfs_mdt_mark_dirty(dat);
  	brelse(req->pr_entry_bh);
  }
  
  static void nilfs_dat_abort_entry(struct inode *dat,
  				  struct nilfs_palloc_req *req)
  {
  	brelse(req->pr_entry_bh);
  }
  
  int nilfs_dat_prepare_alloc(struct inode *dat, struct nilfs_palloc_req *req)
  {
  	int ret;
  
  	ret = nilfs_palloc_prepare_alloc_entry(dat, req);
  	if (ret < 0)
  		return ret;
  
  	ret = nilfs_dat_prepare_entry(dat, req, 1);
  	if (ret < 0)
  		nilfs_palloc_abort_alloc_entry(dat, req);
  
  	return ret;
  }
  
  void nilfs_dat_commit_alloc(struct inode *dat, struct nilfs_palloc_req *req)
  {
  	struct nilfs_dat_entry *entry;
  	void *kaddr;

  	kaddr = kmap_atomic(req->pr_entry_bh->b_page);

  	entry = nilfs_palloc_block_get_entry(dat, req->pr_entry_nr,
  					     req->pr_entry_bh, kaddr);
  	entry->de_start = cpu_to_le64(NILFS_CNO_MIN);
  	entry->de_end = cpu_to_le64(NILFS_CNO_MAX);
  	entry->de_blocknr = cpu_to_le64(0);

  	kunmap_atomic(kaddr);

  
  	nilfs_palloc_commit_alloc_entry(dat, req);
  	nilfs_dat_commit_entry(dat, req);
  }
  
  void nilfs_dat_abort_alloc(struct inode *dat, struct nilfs_palloc_req *req)
  {
  	nilfs_dat_abort_entry(dat, req);
  	nilfs_palloc_abort_alloc_entry(dat, req);
  }

  static void nilfs_dat_commit_free(struct inode *dat,
  				  struct nilfs_palloc_req *req)

  {
  	struct nilfs_dat_entry *entry;
  	void *kaddr;

  	kaddr = kmap_atomic(req->pr_entry_bh->b_page);

  	entry = nilfs_palloc_block_get_entry(dat, req->pr_entry_nr,
  					     req->pr_entry_bh, kaddr);
  	entry->de_start = cpu_to_le64(NILFS_CNO_MIN);
  	entry->de_end = cpu_to_le64(NILFS_CNO_MIN);
  	entry->de_blocknr = cpu_to_le64(0);

  	kunmap_atomic(kaddr);

  
  	nilfs_dat_commit_entry(dat, req);
  	nilfs_palloc_commit_free_entry(dat, req);
  }

  int nilfs_dat_prepare_start(struct inode *dat, struct nilfs_palloc_req *req)
  {
  	int ret;
  
  	ret = nilfs_dat_prepare_entry(dat, req, 0);

  	WARN_ON(ret == -ENOENT);

  	return ret;
  }
  
  void nilfs_dat_commit_start(struct inode *dat, struct nilfs_palloc_req *req,
  			    sector_t blocknr)
  {
  	struct nilfs_dat_entry *entry;
  	void *kaddr;

  	kaddr = kmap_atomic(req->pr_entry_bh->b_page);

  	entry = nilfs_palloc_block_get_entry(dat, req->pr_entry_nr,
  					     req->pr_entry_bh, kaddr);
  	entry->de_start = cpu_to_le64(nilfs_mdt_cno(dat));

  	entry->de_blocknr = cpu_to_le64(blocknr);

  	kunmap_atomic(kaddr);

  
  	nilfs_dat_commit_entry(dat, req);
  }

  int nilfs_dat_prepare_end(struct inode *dat, struct nilfs_palloc_req *req)
  {
  	struct nilfs_dat_entry *entry;
  	__u64 start;
  	sector_t blocknr;
  	void *kaddr;
  	int ret;
  
  	ret = nilfs_dat_prepare_entry(dat, req, 0);
  	if (ret < 0) {

  		WARN_ON(ret == -ENOENT);

  		return ret;
  	}

  	kaddr = kmap_atomic(req->pr_entry_bh->b_page);

  	entry = nilfs_palloc_block_get_entry(dat, req->pr_entry_nr,
  					     req->pr_entry_bh, kaddr);
  	start = le64_to_cpu(entry->de_start);
  	blocknr = le64_to_cpu(entry->de_blocknr);

  	kunmap_atomic(kaddr);

  
  	if (blocknr == 0) {
  		ret = nilfs_palloc_prepare_free_entry(dat, req);
  		if (ret < 0) {
  			nilfs_dat_abort_entry(dat, req);
  			return ret;
  		}
  	}
  
  	return 0;
  }
  
  void nilfs_dat_commit_end(struct inode *dat, struct nilfs_palloc_req *req,
  			  int dead)
  {
  	struct nilfs_dat_entry *entry;
  	__u64 start, end;
  	sector_t blocknr;
  	void *kaddr;

  	kaddr = kmap_atomic(req->pr_entry_bh->b_page);

  	entry = nilfs_palloc_block_get_entry(dat, req->pr_entry_nr,
  					     req->pr_entry_bh, kaddr);
  	end = start = le64_to_cpu(entry->de_start);
  	if (!dead) {
  		end = nilfs_mdt_cno(dat);

  		WARN_ON(start > end);

  	}
  	entry->de_end = cpu_to_le64(end);
  	blocknr = le64_to_cpu(entry->de_blocknr);

  	kunmap_atomic(kaddr);

  
  	if (blocknr == 0)
  		nilfs_dat_commit_free(dat, req);
  	else
  		nilfs_dat_commit_entry(dat, req);
  }
  
  void nilfs_dat_abort_end(struct inode *dat, struct nilfs_palloc_req *req)
  {
  	struct nilfs_dat_entry *entry;
  	__u64 start;
  	sector_t blocknr;
  	void *kaddr;

  	kaddr = kmap_atomic(req->pr_entry_bh->b_page);

  	entry = nilfs_palloc_block_get_entry(dat, req->pr_entry_nr,
  					     req->pr_entry_bh, kaddr);
  	start = le64_to_cpu(entry->de_start);
  	blocknr = le64_to_cpu(entry->de_blocknr);

  	kunmap_atomic(kaddr);

  
  	if (start == nilfs_mdt_cno(dat) && blocknr == 0)
  		nilfs_palloc_abort_free_entry(dat, req);
  	nilfs_dat_abort_entry(dat, req);
  }

  int nilfs_dat_prepare_update(struct inode *dat,
  			     struct nilfs_palloc_req *oldreq,
  			     struct nilfs_palloc_req *newreq)
  {
  	int ret;
  
  	ret = nilfs_dat_prepare_end(dat, oldreq);
  	if (!ret) {
  		ret = nilfs_dat_prepare_alloc(dat, newreq);
  		if (ret < 0)
  			nilfs_dat_abort_end(dat, oldreq);
  	}
  	return ret;
  }
  
  void nilfs_dat_commit_update(struct inode *dat,
  			     struct nilfs_palloc_req *oldreq,
  			     struct nilfs_palloc_req *newreq, int dead)
  {
  	nilfs_dat_commit_end(dat, oldreq, dead);
  	nilfs_dat_commit_alloc(dat, newreq);
  }
  
  void nilfs_dat_abort_update(struct inode *dat,
  			    struct nilfs_palloc_req *oldreq,
  			    struct nilfs_palloc_req *newreq)
  {
  	nilfs_dat_abort_end(dat, oldreq);
  	nilfs_dat_abort_alloc(dat, newreq);
  }

  /**
   * nilfs_dat_mark_dirty -
   * @dat: DAT file inode
   * @vblocknr: virtual block number
   *
   * Description:
   *
   * Return Value: On success, 0 is returned. On error, one of the following
   * negative error codes is returned.
   *
   * %-EIO - I/O error.
   *
   * %-ENOMEM - Insufficient amount of memory available.
   */
  int nilfs_dat_mark_dirty(struct inode *dat, __u64 vblocknr)
  {
  	struct nilfs_palloc_req req;
  	int ret;
  
  	req.pr_entry_nr = vblocknr;
  	ret = nilfs_dat_prepare_entry(dat, &req, 0);
  	if (ret == 0)
  		nilfs_dat_commit_entry(dat, &req);
  	return ret;
  }
  
  /**
   * nilfs_dat_freev - free virtual block numbers
   * @dat: DAT file inode
   * @vblocknrs: array of virtual block numbers
   * @nitems: number of virtual block numbers
   *
   * Description: nilfs_dat_freev() frees the virtual block numbers specified by
   * @vblocknrs and @nitems.
   *
   * Return Value: On success, 0 is returned. On error, one of the following

   * negative error codes is returned.

   *
   * %-EIO - I/O error.
   *
   * %-ENOMEM - Insufficient amount of memory available.
   *
   * %-ENOENT - The virtual block number have not been allocated.
   */
  int nilfs_dat_freev(struct inode *dat, __u64 *vblocknrs, size_t nitems)
  {
  	return nilfs_palloc_freev(dat, vblocknrs, nitems);
  }
  
  /**
   * nilfs_dat_move - change a block number
   * @dat: DAT file inode
   * @vblocknr: virtual block number
   * @blocknr: block number
   *
   * Description: nilfs_dat_move() changes the block number associated with
   * @vblocknr to @blocknr.
   *
   * Return Value: On success, 0 is returned. On error, one of the following
   * negative error codes is returned.
   *
   * %-EIO - I/O error.
   *
   * %-ENOMEM - Insufficient amount of memory available.
   */
  int nilfs_dat_move(struct inode *dat, __u64 vblocknr, sector_t blocknr)
  {
  	struct buffer_head *entry_bh;
  	struct nilfs_dat_entry *entry;
  	void *kaddr;
  	int ret;
  
  	ret = nilfs_palloc_get_entry_block(dat, vblocknr, 0, &entry_bh);
  	if (ret < 0)
  		return ret;

  
  	/*
  	 * The given disk block number (blocknr) is not yet written to
  	 * the device at this point.
  	 *
  	 * To prevent nilfs_dat_translate() from returning the

  	 * uncommitted block number, this makes a copy of the entry

  	 * buffer and redirects nilfs_dat_translate() to the copy.
  	 */
  	if (!buffer_nilfs_redirected(entry_bh)) {
  		ret = nilfs_mdt_freeze_buffer(dat, entry_bh);
  		if (ret) {
  			brelse(entry_bh);
  			return ret;
  		}
  	}

  	kaddr = kmap_atomic(entry_bh->b_page);

  	entry = nilfs_palloc_block_get_entry(dat, vblocknr, entry_bh, kaddr);

  	if (unlikely(entry->de_blocknr == cpu_to_le64(0))) {

  		printk(KERN_CRIT "%s: vbn = %llu, [%llu, %llu)
  ", __func__,
  		       (unsigned long long)vblocknr,
  		       (unsigned long long)le64_to_cpu(entry->de_start),
  		       (unsigned long long)le64_to_cpu(entry->de_end));

  		kunmap_atomic(kaddr);

  		brelse(entry_bh);
  		return -EINVAL;

  	}

  	WARN_ON(blocknr == 0);

  	entry->de_blocknr = cpu_to_le64(blocknr);

  	kunmap_atomic(kaddr);

  	mark_buffer_dirty(entry_bh);

  	nilfs_mdt_mark_dirty(dat);
  
  	brelse(entry_bh);
  
  	return 0;
  }
  
  /**
   * nilfs_dat_translate - translate a virtual block number to a block number
   * @dat: DAT file inode
   * @vblocknr: virtual block number
   * @blocknrp: pointer to a block number
   *
   * Description: nilfs_dat_translate() maps the virtual block number @vblocknr
   * to the corresponding block number.
   *
   * Return Value: On success, 0 is returned and the block number associated
   * with @vblocknr is stored in the place pointed by @blocknrp. On error, one
   * of the following negative error codes is returned.
   *
   * %-EIO - I/O error.
   *
   * %-ENOMEM - Insufficient amount of memory available.
   *
   * %-ENOENT - A block number associated with @vblocknr does not exist.
   */
  int nilfs_dat_translate(struct inode *dat, __u64 vblocknr, sector_t *blocknrp)
  {

  	struct buffer_head *entry_bh, *bh;

  	struct nilfs_dat_entry *entry;
  	sector_t blocknr;
  	void *kaddr;
  	int ret;
  
  	ret = nilfs_palloc_get_entry_block(dat, vblocknr, 0, &entry_bh);
  	if (ret < 0)
  		return ret;

  	if (!nilfs_doing_gc() && buffer_nilfs_redirected(entry_bh)) {
  		bh = nilfs_mdt_get_frozen_buffer(dat, entry_bh);
  		if (bh) {
  			WARN_ON(!buffer_uptodate(bh));
  			brelse(entry_bh);
  			entry_bh = bh;
  		}
  	}

  	kaddr = kmap_atomic(entry_bh->b_page);

  	entry = nilfs_palloc_block_get_entry(dat, vblocknr, entry_bh, kaddr);
  	blocknr = le64_to_cpu(entry->de_blocknr);
  	if (blocknr == 0) {
  		ret = -ENOENT;
  		goto out;
  	}

  	*blocknrp = blocknr;

  
   out:

  	kunmap_atomic(kaddr);

  	brelse(entry_bh);
  	return ret;
  }

  ssize_t nilfs_dat_get_vinfo(struct inode *dat, void *buf, unsigned visz,

  			    size_t nvi)
  {
  	struct buffer_head *entry_bh;
  	struct nilfs_dat_entry *entry;

  	struct nilfs_vinfo *vinfo = buf;

  	__u64 first, last;
  	void *kaddr;
  	unsigned long entries_per_block = NILFS_MDT(dat)->mi_entries_per_block;
  	int i, j, n, ret;
  
  	for (i = 0; i < nvi; i += n) {

  		ret = nilfs_palloc_get_entry_block(dat, vinfo->vi_vblocknr,

  						   0, &entry_bh);
  		if (ret < 0)
  			return ret;

  		kaddr = kmap_atomic(entry_bh->b_page);

  		/* last virtual block number in this block */

  		first = vinfo->vi_vblocknr;

  		do_div(first, entries_per_block);
  		first *= entries_per_block;
  		last = first + entries_per_block - 1;
  		for (j = i, n = 0;

  		     j < nvi && vinfo->vi_vblocknr >= first &&
  			     vinfo->vi_vblocknr <= last;
  		     j++, n++, vinfo = (void *)vinfo + visz) {

  			entry = nilfs_palloc_block_get_entry(

  				dat, vinfo->vi_vblocknr, entry_bh, kaddr);
  			vinfo->vi_start = le64_to_cpu(entry->de_start);
  			vinfo->vi_end = le64_to_cpu(entry->de_end);
  			vinfo->vi_blocknr = le64_to_cpu(entry->de_blocknr);

  		}

  		kunmap_atomic(kaddr);

  		brelse(entry_bh);
  	}
  
  	return nvi;
  }

  
  /**

   * nilfs_dat_read - read or get dat inode
   * @sb: super block instance

   * @entry_size: size of a dat entry

   * @raw_inode: on-disk dat inode
   * @inodep: buffer to store the inode

   */

  int nilfs_dat_read(struct super_block *sb, size_t entry_size,
  		   struct nilfs_inode *raw_inode, struct inode **inodep)

  {
  	static struct lock_class_key dat_lock_key;
  	struct inode *dat;

  	struct nilfs_dat_info *di;

  	int err;

  	dat = nilfs_iget_locked(sb, NULL, NILFS_DAT_INO);
  	if (unlikely(!dat))
  		return -ENOMEM;
  	if (!(dat->i_state & I_NEW))
  		goto out;

  	err = nilfs_mdt_init(dat, NILFS_MDT_GFP, sizeof(*di));
  	if (err)
  		goto failed;
  
  	err = nilfs_palloc_init_blockgroup(dat, entry_size);
  	if (err)
  		goto failed;
  
  	di = NILFS_DAT_I(dat);
  	lockdep_set_class(&di->mi.mi_sem, &dat_lock_key);
  	nilfs_palloc_setup_cache(dat, &di->palloc_cache);
  	nilfs_mdt_setup_shadow_map(dat, &di->shadow);
  
  	err = nilfs_read_inode_common(dat, raw_inode);
  	if (err)
  		goto failed;
  
  	unlock_new_inode(dat);
   out:
  	*inodep = dat;
  	return 0;
   failed:
  	iget_failed(dat);
  	return err;

  }