/*
   * bmap.c - NILFS block mapping.
   *
   * 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.
   *

   * Written by Koji Sato.

   */
  
  #include <linux/fs.h>
  #include <linux/string.h>
  #include <linux/errno.h>
  #include "nilfs.h"
  #include "bmap.h"

  #include "btree.h"
  #include "direct.h"

  #include "btnode.h"
  #include "mdt.h"
  #include "dat.h"
  #include "alloc.h"

  struct inode *nilfs_bmap_get_dat(const struct nilfs_bmap *bmap)

  {

  	struct the_nilfs *nilfs = bmap->b_inode->i_sb->s_fs_info;
  
  	return nilfs->ns_dat;

  }

  static int nilfs_bmap_convert_error(struct nilfs_bmap *bmap,
  				     const char *fname, int err)
  {
  	struct inode *inode = bmap->b_inode;
  
  	if (err == -EINVAL) {

  		__nilfs_error(inode->i_sb, fname,
  			      "broken bmap (inode number=%lu)", inode->i_ino);

  		err = -EIO;
  	}
  	return err;
  }

  /**
   * nilfs_bmap_lookup_at_level - find a data block or node block
   * @bmap: bmap
   * @key: key
   * @level: level
   * @ptrp: place to store the value associated to @key
   *
   * Description: nilfs_bmap_lookup_at_level() finds a record whose key
   * matches @key in the block at @level of the bmap.
   *
   * Return Value: On success, 0 is returned and the record associated with @key
   * is stored in the place pointed by @ptrp. On error, one of the following
   * negative error codes is returned.
   *
   * %-EIO - I/O error.
   *
   * %-ENOMEM - Insufficient amount of memory available.
   *
   * %-ENOENT - A record associated with @key does not exist.
   */

  int nilfs_bmap_lookup_at_level(struct nilfs_bmap *bmap, __u64 key, int level,
  			       __u64 *ptrp)
  {

  	sector_t blocknr;

  	int ret;
  
  	down_read(&bmap->b_sem);

  	ret = bmap->b_ops->bop_lookup(bmap, key, level, ptrp);

  	if (ret < 0) {
  		ret = nilfs_bmap_convert_error(bmap, __func__, ret);

  		goto out;

  	}

  	if (NILFS_BMAP_USE_VBN(bmap)) {
  		ret = nilfs_dat_translate(nilfs_bmap_get_dat(bmap), *ptrp,
  					  &blocknr);
  		if (!ret)
  			*ptrp = blocknr;

  	}
  
   out:
  	up_read(&bmap->b_sem);
  	return ret;
  }

  int nilfs_bmap_lookup_contig(struct nilfs_bmap *bmap, __u64 key, __u64 *ptrp,

  			     unsigned int maxblocks)

  {
  	int ret;
  
  	down_read(&bmap->b_sem);
  	ret = bmap->b_ops->bop_lookup_contig(bmap, key, ptrp, maxblocks);
  	up_read(&bmap->b_sem);

  
  	return nilfs_bmap_convert_error(bmap, __func__, ret);

  }

  static int nilfs_bmap_do_insert(struct nilfs_bmap *bmap, __u64 key, __u64 ptr)
  {
  	__u64 keys[NILFS_BMAP_SMALL_HIGH + 1];
  	__u64 ptrs[NILFS_BMAP_SMALL_HIGH + 1];
  	int ret, n;
  
  	if (bmap->b_ops->bop_check_insert != NULL) {

  		ret = bmap->b_ops->bop_check_insert(bmap, key);

  		if (ret > 0) {

  			n = bmap->b_ops->bop_gather_data(

  				bmap, keys, ptrs, NILFS_BMAP_SMALL_HIGH + 1);
  			if (n < 0)
  				return n;
  			ret = nilfs_btree_convert_and_insert(

  				bmap, key, ptr, keys, ptrs, n);

  			if (ret == 0)
  				bmap->b_u.u_flags |= NILFS_BMAP_LARGE;
  
  			return ret;
  		} else if (ret < 0)
  			return ret;
  	}

  	return bmap->b_ops->bop_insert(bmap, key, ptr);

  }
  
  /**
   * nilfs_bmap_insert - insert a new key-record pair into a bmap
   * @bmap: bmap
   * @key: key
   * @rec: record
   *
   * Description: nilfs_bmap_insert() inserts the new key-record pair specified
   * by @key and @rec into @bmap.
   *
   * 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.
   *
   * %-EEXIST - A record associated with @key already exist.
   */

  int nilfs_bmap_insert(struct nilfs_bmap *bmap, __u64 key, unsigned long rec)

  {
  	int ret;
  
  	down_write(&bmap->b_sem);
  	ret = nilfs_bmap_do_insert(bmap, key, rec);
  	up_write(&bmap->b_sem);

  
  	return nilfs_bmap_convert_error(bmap, __func__, ret);

  }
  
  static int nilfs_bmap_do_delete(struct nilfs_bmap *bmap, __u64 key)
  {
  	__u64 keys[NILFS_BMAP_LARGE_LOW + 1];
  	__u64 ptrs[NILFS_BMAP_LARGE_LOW + 1];
  	int ret, n;
  
  	if (bmap->b_ops->bop_check_delete != NULL) {

  		ret = bmap->b_ops->bop_check_delete(bmap, key);

  		if (ret > 0) {

  			n = bmap->b_ops->bop_gather_data(

  				bmap, keys, ptrs, NILFS_BMAP_LARGE_LOW + 1);
  			if (n < 0)
  				return n;
  			ret = nilfs_direct_delete_and_convert(

  				bmap, key, keys, ptrs, n);

  			if (ret == 0)
  				bmap->b_u.u_flags &= ~NILFS_BMAP_LARGE;
  
  			return ret;
  		} else if (ret < 0)
  			return ret;
  	}

  	return bmap->b_ops->bop_delete(bmap, key);

  }

  /**
   * nilfs_bmap_seek_key - seek a valid entry and return its key
   * @bmap: bmap struct
   * @start: start key number
   * @keyp: place to store valid key
   *
   * Description: nilfs_bmap_seek_key() seeks a valid key on @bmap
   * starting from @start, and stores it to @keyp if found.
   *
   * 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 - No valid entry was found
   */
  int nilfs_bmap_seek_key(struct nilfs_bmap *bmap, __u64 start, __u64 *keyp)
  {
  	int ret;
  
  	down_read(&bmap->b_sem);
  	ret = bmap->b_ops->bop_seek_key(bmap, start, keyp);
  	up_read(&bmap->b_sem);
  
  	if (ret < 0)
  		ret = nilfs_bmap_convert_error(bmap, __func__, ret);
  	return ret;
  }

  int nilfs_bmap_last_key(struct nilfs_bmap *bmap, __u64 *keyp)

  {

  	int ret;
  
  	down_read(&bmap->b_sem);

  	ret = bmap->b_ops->bop_last_key(bmap, keyp);

  	up_read(&bmap->b_sem);

  
  	if (ret < 0)
  		ret = nilfs_bmap_convert_error(bmap, __func__, ret);

  	return ret;
  }
  
  /**
   * nilfs_bmap_delete - delete a key-record pair from a bmap
   * @bmap: bmap
   * @key: key
   *
   * Description: nilfs_bmap_delete() deletes the key-record pair specified by
   * @key from @bmap.
   *
   * 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 - A record associated with @key does not exist.
   */

  int nilfs_bmap_delete(struct nilfs_bmap *bmap, __u64 key)

  {
  	int ret;
  
  	down_write(&bmap->b_sem);
  	ret = nilfs_bmap_do_delete(bmap, key);
  	up_write(&bmap->b_sem);

  
  	return nilfs_bmap_convert_error(bmap, __func__, ret);

  }

  static int nilfs_bmap_do_truncate(struct nilfs_bmap *bmap, __u64 key)

  {
  	__u64 lastkey;
  	int ret;

  	ret = bmap->b_ops->bop_last_key(bmap, &lastkey);

  	if (ret < 0) {
  		if (ret == -ENOENT)
  			ret = 0;
  		return ret;
  	}
  
  	while (key <= lastkey) {
  		ret = nilfs_bmap_do_delete(bmap, lastkey);
  		if (ret < 0)
  			return ret;

  		ret = bmap->b_ops->bop_last_key(bmap, &lastkey);

  		if (ret < 0) {
  			if (ret == -ENOENT)
  				ret = 0;
  			return ret;
  		}
  	}
  	return 0;
  }
  
  /**
   * nilfs_bmap_truncate - truncate a bmap to a specified key
   * @bmap: bmap
   * @key: key
   *
   * Description: nilfs_bmap_truncate() removes key-record pairs whose keys are
   * greater than or equal to @key from @bmap.
   *
   * 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_bmap_truncate(struct nilfs_bmap *bmap, __u64 key)

  {
  	int ret;
  
  	down_write(&bmap->b_sem);
  	ret = nilfs_bmap_do_truncate(bmap, key);
  	up_write(&bmap->b_sem);

  
  	return nilfs_bmap_convert_error(bmap, __func__, ret);

  }
  
  /**
   * nilfs_bmap_clear - free resources a bmap holds
   * @bmap: bmap
   *
   * Description: nilfs_bmap_clear() frees resources associated with @bmap.
   */
  void nilfs_bmap_clear(struct nilfs_bmap *bmap)
  {
  	down_write(&bmap->b_sem);
  	if (bmap->b_ops->bop_clear != NULL)

  		bmap->b_ops->bop_clear(bmap);

  	up_write(&bmap->b_sem);
  }
  
  /**
   * nilfs_bmap_propagate - propagate dirty state
   * @bmap: bmap
   * @bh: buffer head
   *
   * Description: nilfs_bmap_propagate() marks the buffers that directly or
   * indirectly refer to the block specified by @bh dirty.
   *
   * 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_bmap_propagate(struct nilfs_bmap *bmap, struct buffer_head *bh)
  {
  	int ret;
  
  	down_write(&bmap->b_sem);

  	ret = bmap->b_ops->bop_propagate(bmap, bh);

  	up_write(&bmap->b_sem);

  
  	return nilfs_bmap_convert_error(bmap, __func__, ret);

  }
  
  /**
   * nilfs_bmap_lookup_dirty_buffers -
   * @bmap: bmap
   * @listp: pointer to buffer head list
   */
  void nilfs_bmap_lookup_dirty_buffers(struct nilfs_bmap *bmap,
  				     struct list_head *listp)
  {
  	if (bmap->b_ops->bop_lookup_dirty_buffers != NULL)

  		bmap->b_ops->bop_lookup_dirty_buffers(bmap, listp);

  }
  
  /**
   * nilfs_bmap_assign - assign a new block number to a block
   * @bmap: bmap
   * @bhp: pointer to buffer head
   * @blocknr: block number
   * @binfo: block information
   *
   * Description: nilfs_bmap_assign() assigns the block number @blocknr to the
   * buffer specified by @bh.
   *
   * Return Value: On success, 0 is returned and the buffer head of a newly
   * create buffer and the block information associated with the buffer are
   * stored in the place pointed by @bh and @binfo, respectively. On error, one
   * of the following negative error codes is returned.
   *
   * %-EIO - I/O error.
   *
   * %-ENOMEM - Insufficient amount of memory available.
   */
  int nilfs_bmap_assign(struct nilfs_bmap *bmap,
  		      struct buffer_head **bh,
  		      unsigned long blocknr,
  		      union nilfs_binfo *binfo)
  {
  	int ret;
  
  	down_write(&bmap->b_sem);

  	ret = bmap->b_ops->bop_assign(bmap, bh, blocknr, binfo);

  	up_write(&bmap->b_sem);

  
  	return nilfs_bmap_convert_error(bmap, __func__, ret);

  }
  
  /**
   * nilfs_bmap_mark - mark block dirty
   * @bmap: bmap
   * @key: key
   * @level: level
   *
   * Description: nilfs_bmap_mark() marks the block specified by @key and @level
   * as dirty.
   *
   * 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_bmap_mark(struct nilfs_bmap *bmap, __u64 key, int level)
  {
  	int ret;
  
  	if (bmap->b_ops->bop_mark == NULL)
  		return 0;
  
  	down_write(&bmap->b_sem);

  	ret = bmap->b_ops->bop_mark(bmap, key, level);

  	up_write(&bmap->b_sem);

  
  	return nilfs_bmap_convert_error(bmap, __func__, ret);

  }
  
  /**
   * nilfs_bmap_test_and_clear_dirty - test and clear a bmap dirty state
   * @bmap: bmap
   *
   * Description: nilfs_test_and_clear() is the atomic operation to test and
   * clear the dirty state of @bmap.
   *
   * Return Value: 1 is returned if @bmap is dirty, or 0 if clear.
   */
  int nilfs_bmap_test_and_clear_dirty(struct nilfs_bmap *bmap)
  {
  	int ret;
  
  	down_write(&bmap->b_sem);
  	ret = nilfs_bmap_dirty(bmap);
  	nilfs_bmap_clear_dirty(bmap);
  	up_write(&bmap->b_sem);
  	return ret;
  }
  
  
  /*
   * Internal use only
   */

  __u64 nilfs_bmap_data_get_key(const struct nilfs_bmap *bmap,
  			      const struct buffer_head *bh)
  {
  	struct buffer_head *pbh;
  	__u64 key;

  	key = page_index(bh->b_page) << (PAGE_SHIFT -

  					 bmap->b_inode->i_blkbits);

  	for (pbh = page_buffers(bh->b_page); pbh != bh; pbh = pbh->b_this_page)
  		key++;

  
  	return key;
  }
  
  __u64 nilfs_bmap_find_target_seq(const struct nilfs_bmap *bmap, __u64 key)
  {
  	__s64 diff;
  
  	diff = key - bmap->b_last_allocated_key;
  	if ((nilfs_bmap_keydiff_abs(diff) < NILFS_INODE_BMAP_SIZE) &&
  	    (bmap->b_last_allocated_ptr != NILFS_BMAP_INVALID_PTR) &&
  	    (bmap->b_last_allocated_ptr + diff > 0))
  		return bmap->b_last_allocated_ptr + diff;
  	else
  		return NILFS_BMAP_INVALID_PTR;
  }

  #define NILFS_BMAP_GROUP_DIV	8
  __u64 nilfs_bmap_find_target_in_group(const struct nilfs_bmap *bmap)
  {
  	struct inode *dat = nilfs_bmap_get_dat(bmap);
  	unsigned long entries_per_group = nilfs_palloc_entries_per_group(dat);
  	unsigned long group = bmap->b_inode->i_ino / entries_per_group;
  
  	return group * entries_per_group +
  		(bmap->b_inode->i_ino % NILFS_BMAP_GROUP_DIV) *
  		(entries_per_group / NILFS_BMAP_GROUP_DIV);
  }

  static struct lock_class_key nilfs_bmap_dat_lock_key;

  static struct lock_class_key nilfs_bmap_mdt_lock_key;

  /**
   * nilfs_bmap_read - read a bmap from an inode
   * @bmap: bmap
   * @raw_inode: on-disk inode
   *
   * Description: nilfs_bmap_read() initializes the bmap @bmap.
   *
   * Return Value: On success, 0 is returned. On error, the following negative
   * error code is returned.
   *
   * %-ENOMEM - Insufficient amount of memory available.
   */
  int nilfs_bmap_read(struct nilfs_bmap *bmap, struct nilfs_inode *raw_inode)
  {
  	if (raw_inode == NULL)
  		memset(bmap->b_u.u_data, 0, NILFS_BMAP_SIZE);
  	else
  		memcpy(bmap->b_u.u_data, raw_inode->i_bmap, NILFS_BMAP_SIZE);
  
  	init_rwsem(&bmap->b_sem);
  	bmap->b_state = 0;
  	bmap->b_inode = &NILFS_BMAP_I(bmap)->vfs_inode;
  	switch (bmap->b_inode->i_ino) {
  	case NILFS_DAT_INO:

  		bmap->b_ptr_type = NILFS_BMAP_PTR_P;
  		bmap->b_last_allocated_key = 0;

  		bmap->b_last_allocated_ptr = NILFS_BMAP_NEW_PTR_INIT;

  		lockdep_set_class(&bmap->b_sem, &nilfs_bmap_dat_lock_key);

  		break;
  	case NILFS_CPFILE_INO:
  	case NILFS_SUFILE_INO:

  		bmap->b_ptr_type = NILFS_BMAP_PTR_VS;
  		bmap->b_last_allocated_key = 0;

  		bmap->b_last_allocated_ptr = NILFS_BMAP_INVALID_PTR;

  		lockdep_set_class(&bmap->b_sem, &nilfs_bmap_mdt_lock_key);

  		break;

  	case NILFS_IFILE_INO:
  		lockdep_set_class(&bmap->b_sem, &nilfs_bmap_mdt_lock_key);
  		/* Fall through */

  	default:

  		bmap->b_ptr_type = NILFS_BMAP_PTR_VM;
  		bmap->b_last_allocated_key = 0;

  		bmap->b_last_allocated_ptr = NILFS_BMAP_INVALID_PTR;
  		break;
  	}
  
  	return (bmap->b_u.u_flags & NILFS_BMAP_LARGE) ?

  		nilfs_btree_init(bmap) : nilfs_direct_init(bmap);

  }
  
  /**
   * nilfs_bmap_write - write back a bmap to an inode
   * @bmap: bmap
   * @raw_inode: on-disk inode
   *
   * Description: nilfs_bmap_write() stores @bmap in @raw_inode.
   */
  void nilfs_bmap_write(struct nilfs_bmap *bmap, struct nilfs_inode *raw_inode)
  {
  	down_write(&bmap->b_sem);
  	memcpy(raw_inode->i_bmap, bmap->b_u.u_data,
  	       NILFS_INODE_BMAP_SIZE * sizeof(__le64));
  	if (bmap->b_inode->i_ino == NILFS_DAT_INO)
  		bmap->b_last_allocated_ptr = NILFS_BMAP_NEW_PTR_INIT;
  
  	up_write(&bmap->b_sem);
  }
  
  void nilfs_bmap_init_gc(struct nilfs_bmap *bmap)
  {
  	memset(&bmap->b_u, 0, NILFS_BMAP_SIZE);
  	init_rwsem(&bmap->b_sem);
  	bmap->b_inode = &NILFS_BMAP_I(bmap)->vfs_inode;

  	bmap->b_ptr_type = NILFS_BMAP_PTR_U;

  	bmap->b_last_allocated_key = 0;
  	bmap->b_last_allocated_ptr = NILFS_BMAP_INVALID_PTR;
  	bmap->b_state = 0;
  	nilfs_btree_init_gc(bmap);
  }

  void nilfs_bmap_save(const struct nilfs_bmap *bmap,
  		     struct nilfs_bmap_store *store)
  {
  	memcpy(store->data, bmap->b_u.u_data, sizeof(store->data));
  	store->last_allocated_key = bmap->b_last_allocated_key;
  	store->last_allocated_ptr = bmap->b_last_allocated_ptr;
  	store->state = bmap->b_state;
  }
  
  void nilfs_bmap_restore(struct nilfs_bmap *bmap,
  			const struct nilfs_bmap_store *store)
  {
  	memcpy(bmap->b_u.u_data, store->data, sizeof(store->data));
  	bmap->b_last_allocated_key = store->last_allocated_key;
  	bmap->b_last_allocated_ptr = store->last_allocated_ptr;
  	bmap->b_state = store->state;
  }