/*

   * fs/f2fs/data.c
   *
   * Copyright (c) 2012 Samsung Electronics Co., Ltd.
   *             http://www.samsung.com/
   *
   * 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/buffer_head.h>
  #include <linux/mpage.h>
  #include <linux/writeback.h>
  #include <linux/backing-dev.h>

  #include <linux/pagevec.h>

  #include <linux/blkdev.h>
  #include <linux/bio.h>

  #include <linux/prefetch.h>

  #include <linux/uio.h>

  #include <linux/mm.h>
  #include <linux/memcontrol.h>

  #include <linux/cleancache.h>

  
  #include "f2fs.h"
  #include "node.h"
  #include "segment.h"

  #include "trace.h"

  #include <trace/events/f2fs.h>

  static void f2fs_read_end_io(struct bio *bio)

  {

  	struct bio_vec *bvec;
  	int i;

  #ifdef CONFIG_F2FS_FAULT_INJECTION

  	if (time_to_inject(F2FS_P_SB(bio->bi_io_vec->bv_page), FAULT_IO))

  		bio->bi_error = -EIO;
  #endif

  	if (f2fs_bio_encrypted(bio)) {

  		if (bio->bi_error) {

  			fscrypt_release_ctx(bio->bi_private);

  		} else {

  			fscrypt_decrypt_bio_pages(bio->bi_private, bio);

  			return;
  		}
  	}

  	bio_for_each_segment_all(bvec, bio, i) {
  		struct page *page = bvec->bv_page;

  		if (!bio->bi_error) {

  			if (!PageUptodate(page))
  				SetPageUptodate(page);

  		} else {
  			ClearPageUptodate(page);
  			SetPageError(page);
  		}
  		unlock_page(page);
  	}

  	bio_put(bio);
  }

  static void f2fs_write_end_io(struct bio *bio)

  {

  	struct f2fs_sb_info *sbi = bio->bi_private;

  	struct bio_vec *bvec;
  	int i;

  	bio_for_each_segment_all(bvec, bio, i) {

  		struct page *page = bvec->bv_page;

  		fscrypt_pullback_bio_page(&page, true);

  		if (unlikely(bio->bi_error)) {

  			mapping_set_error(page->mapping, -EIO);

  			f2fs_stop_checkpoint(sbi, true);

  		}
  		end_page_writeback(page);

  	}

  	if (atomic_dec_and_test(&sbi->nr_wb_bios) &&
  				wq_has_sleeper(&sbi->cp_wait))

  		wake_up(&sbi->cp_wait);
  
  	bio_put(bio);
  }

  /*
   * Low-level block read/write IO operations.
   */
  static struct bio *__bio_alloc(struct f2fs_sb_info *sbi, block_t blk_addr,
  				int npages, bool is_read)
  {
  	struct bio *bio;

  	bio = f2fs_bio_alloc(npages);

  
  	bio->bi_bdev = sbi->sb->s_bdev;

  	bio->bi_iter.bi_sector = SECTOR_FROM_BLOCK(blk_addr);

  	bio->bi_end_io = is_read ? f2fs_read_end_io : f2fs_write_end_io;

  	bio->bi_private = is_read ? NULL : sbi;

  
  	return bio;
  }

  static inline void __submit_bio(struct f2fs_sb_info *sbi,
  				struct bio *bio, enum page_type type)

  {

  	if (!is_read_io(bio_op(bio))) {

  		atomic_inc(&sbi->nr_wb_bios);

  		if (f2fs_sb_mounted_hmsmr(sbi->sb) &&
  			current->plug && (type == DATA || type == NODE))

  			blk_finish_plug(current->plug);
  	}

  	submit_bio(bio);

  }

  static void __submit_merged_bio(struct f2fs_bio_info *io)

  {

  	struct f2fs_io_info *fio = &io->fio;

  
  	if (!io->bio)
  		return;

  	if (is_read_io(fio->op))

  		trace_f2fs_submit_read_bio(io->sbi->sb, fio, io->bio);

  	else

  		trace_f2fs_submit_write_bio(io->sbi->sb, fio, io->bio);

  	bio_set_op_attrs(io->bio, fio->op, fio->op_flags);

  	__submit_bio(io->sbi, io->bio, fio->type);

  	io->bio = NULL;
  }

  static bool __has_merged_page(struct f2fs_bio_info *io, struct inode *inode,
  						struct page *page, nid_t ino)

  {

  	struct bio_vec *bvec;
  	struct page *target;
  	int i;

  	if (!io->bio)

  		return false;

  
  	if (!inode && !page && !ino)
  		return true;

  
  	bio_for_each_segment_all(bvec, io->bio, i) {

  		if (bvec->bv_page->mapping)

  			target = bvec->bv_page;

  		else
  			target = fscrypt_control_page(bvec->bv_page);

  		if (inode && inode == target->mapping->host)
  			return true;
  		if (page && page == target)
  			return true;
  		if (ino && ino == ino_of_node(target))

  			return true;

  	}

  	return false;
  }

  static bool has_merged_page(struct f2fs_sb_info *sbi, struct inode *inode,
  						struct page *page, nid_t ino,
  						enum page_type type)
  {
  	enum page_type btype = PAGE_TYPE_OF_BIO(type);
  	struct f2fs_bio_info *io = &sbi->write_io[btype];
  	bool ret;
  
  	down_read(&io->io_rwsem);
  	ret = __has_merged_page(io, inode, page, ino);
  	up_read(&io->io_rwsem);
  	return ret;
  }
  
  static void __f2fs_submit_merged_bio(struct f2fs_sb_info *sbi,
  				struct inode *inode, struct page *page,
  				nid_t ino, enum page_type type, int rw)

  {
  	enum page_type btype = PAGE_TYPE_OF_BIO(type);
  	struct f2fs_bio_info *io;
  
  	io = is_read_io(rw) ? &sbi->read_io : &sbi->write_io[btype];

  	down_write(&io->io_rwsem);

  	if (!__has_merged_page(io, inode, page, ino))
  		goto out;

  	/* change META to META_FLUSH in the checkpoint procedure */
  	if (type >= META_FLUSH) {
  		io->fio.type = META_FLUSH;

  		io->fio.op = REQ_OP_WRITE;

  		if (test_opt(sbi, NOBARRIER))

  			io->fio.op_flags = WRITE_FLUSH | REQ_META | REQ_PRIO;

  		else

  			io->fio.op_flags = WRITE_FLUSH_FUA | REQ_META |
  								REQ_PRIO;

  	}
  	__submit_merged_bio(io);

  out:

  	up_write(&io->io_rwsem);

  }

  void f2fs_submit_merged_bio(struct f2fs_sb_info *sbi, enum page_type type,
  									int rw)
  {
  	__f2fs_submit_merged_bio(sbi, NULL, NULL, 0, type, rw);
  }
  
  void f2fs_submit_merged_bio_cond(struct f2fs_sb_info *sbi,
  				struct inode *inode, struct page *page,
  				nid_t ino, enum page_type type, int rw)
  {
  	if (has_merged_page(sbi, inode, page, ino, type))
  		__f2fs_submit_merged_bio(sbi, inode, page, ino, type, rw);
  }

  void f2fs_flush_merged_bios(struct f2fs_sb_info *sbi)
  {
  	f2fs_submit_merged_bio(sbi, DATA, WRITE);
  	f2fs_submit_merged_bio(sbi, NODE, WRITE);
  	f2fs_submit_merged_bio(sbi, META, WRITE);
  }

  /*
   * Fill the locked page with data located in the block address.
   * Return unlocked page.
   */

  int f2fs_submit_page_bio(struct f2fs_io_info *fio)

  {

  	struct bio *bio;

  	struct page *page = fio->encrypted_page ?
  			fio->encrypted_page : fio->page;

  	trace_f2fs_submit_page_bio(page, fio);

  	f2fs_trace_ios(fio, 0);

  
  	/* Allocate a new bio */

  	bio = __bio_alloc(fio->sbi, fio->new_blkaddr, 1, is_read_io(fio->op));

  	if (bio_add_page(bio, page, PAGE_SIZE, 0) < PAGE_SIZE) {

  		bio_put(bio);

  		return -EFAULT;
  	}

  	bio_set_op_attrs(bio, fio->op, fio->op_flags);

  	__submit_bio(fio->sbi, bio, fio->type);

  	return 0;
  }

  void f2fs_submit_page_mbio(struct f2fs_io_info *fio)

  {

  	struct f2fs_sb_info *sbi = fio->sbi;

  	enum page_type btype = PAGE_TYPE_OF_BIO(fio->type);

  	struct f2fs_bio_info *io;

  	bool is_read = is_read_io(fio->op);

  	struct page *bio_page;

  	io = is_read ? &sbi->read_io : &sbi->write_io[btype];

  	if (fio->old_blkaddr != NEW_ADDR)
  		verify_block_addr(sbi, fio->old_blkaddr);
  	verify_block_addr(sbi, fio->new_blkaddr);

  	down_write(&io->io_rwsem);

  	if (io->bio && (io->last_block_in_bio != fio->new_blkaddr - 1 ||

  	    (io->fio.op != fio->op || io->fio.op_flags != fio->op_flags)))

  		__submit_merged_bio(io);

  alloc_new:
  	if (io->bio == NULL) {

  		int bio_blocks = MAX_BIO_BLOCKS(sbi);

  		io->bio = __bio_alloc(sbi, fio->new_blkaddr,
  						bio_blocks, is_read);

  		io->fio = *fio;

  	}

  	bio_page = fio->encrypted_page ? fio->encrypted_page : fio->page;

  	if (bio_add_page(io->bio, bio_page, PAGE_SIZE, 0) <
  							PAGE_SIZE) {

  		__submit_merged_bio(io);

  		goto alloc_new;
  	}

  	io->last_block_in_bio = fio->new_blkaddr;

  	f2fs_trace_ios(fio, 0);

  	up_write(&io->io_rwsem);

  	trace_f2fs_submit_page_mbio(fio->page, fio);

  }

  static void __set_data_blkaddr(struct dnode_of_data *dn)
  {
  	struct f2fs_node *rn = F2FS_NODE(dn->node_page);
  	__le32 *addr_array;
  
  	/* Get physical address of data block */
  	addr_array = blkaddr_in_node(rn);
  	addr_array[dn->ofs_in_node] = cpu_to_le32(dn->data_blkaddr);
  }

  /*

   * Lock ordering for the change of data block address:
   * ->data_page
   *  ->node_page
   *    update block addresses in the node page
   */

  void set_data_blkaddr(struct dnode_of_data *dn)

  {

  	f2fs_wait_on_page_writeback(dn->node_page, NODE, true);
  	__set_data_blkaddr(dn);
  	if (set_page_dirty(dn->node_page))

  		dn->node_changed = true;

  }

  void f2fs_update_data_blkaddr(struct dnode_of_data *dn, block_t blkaddr)
  {
  	dn->data_blkaddr = blkaddr;
  	set_data_blkaddr(dn);
  	f2fs_update_extent_cache(dn);
  }

  /* dn->ofs_in_node will be returned with up-to-date last block pointer */
  int reserve_new_blocks(struct dnode_of_data *dn, blkcnt_t count)

  {

  	struct f2fs_sb_info *sbi = F2FS_I_SB(dn->inode);

  	if (!count)
  		return 0;

  	if (unlikely(is_inode_flag_set(dn->inode, FI_NO_ALLOC)))

  		return -EPERM;

  	if (unlikely(!inc_valid_block_count(sbi, dn->inode, &count)))

  		return -ENOSPC;

  	trace_f2fs_reserve_new_blocks(dn->inode, dn->nid,
  						dn->ofs_in_node, count);
  
  	f2fs_wait_on_page_writeback(dn->node_page, NODE, true);
  
  	for (; count > 0; dn->ofs_in_node++) {
  		block_t blkaddr =
  			datablock_addr(dn->node_page, dn->ofs_in_node);
  		if (blkaddr == NULL_ADDR) {
  			dn->data_blkaddr = NEW_ADDR;
  			__set_data_blkaddr(dn);
  			count--;
  		}
  	}
  
  	if (set_page_dirty(dn->node_page))
  		dn->node_changed = true;

  	return 0;
  }

  /* Should keep dn->ofs_in_node unchanged */
  int reserve_new_block(struct dnode_of_data *dn)
  {
  	unsigned int ofs_in_node = dn->ofs_in_node;
  	int ret;
  
  	ret = reserve_new_blocks(dn, 1);
  	dn->ofs_in_node = ofs_in_node;
  	return ret;
  }

  int f2fs_reserve_block(struct dnode_of_data *dn, pgoff_t index)
  {
  	bool need_put = dn->inode_page ? false : true;
  	int err;
  
  	err = get_dnode_of_data(dn, index, ALLOC_NODE);
  	if (err)
  		return err;

  	if (dn->data_blkaddr == NULL_ADDR)
  		err = reserve_new_block(dn);

  	if (err || need_put)

  		f2fs_put_dnode(dn);
  	return err;
  }

  int f2fs_get_block(struct dnode_of_data *dn, pgoff_t index)

  {

  	struct extent_info ei;

  	struct inode *inode = dn->inode;

  	if (f2fs_lookup_extent_cache(inode, index, &ei)) {
  		dn->data_blkaddr = ei.blk + index - ei.fofs;
  		return 0;

  	}

  	return f2fs_reserve_block(dn, index);

  }

  struct page *get_read_data_page(struct inode *inode, pgoff_t index,

  						int op_flags, bool for_write)

  {

  	struct address_space *mapping = inode->i_mapping;
  	struct dnode_of_data dn;
  	struct page *page;

  	struct extent_info ei;

  	int err;

  	struct f2fs_io_info fio = {

  		.sbi = F2FS_I_SB(inode),

  		.type = DATA,

  		.op = REQ_OP_READ,
  		.op_flags = op_flags,

  		.encrypted_page = NULL,

  	};

  	if (f2fs_encrypted_inode(inode) && S_ISREG(inode->i_mode))
  		return read_mapping_page(mapping, index, NULL);

  	page = f2fs_grab_cache_page(mapping, index, for_write);

  	if (!page)
  		return ERR_PTR(-ENOMEM);

  	if (f2fs_lookup_extent_cache(inode, index, &ei)) {
  		dn.data_blkaddr = ei.blk + index - ei.fofs;
  		goto got_it;
  	}

  	set_new_dnode(&dn, inode, NULL, NULL, 0);

  	err = get_dnode_of_data(&dn, index, LOOKUP_NODE);

  	if (err)
  		goto put_err;

  	f2fs_put_dnode(&dn);

  	if (unlikely(dn.data_blkaddr == NULL_ADDR)) {

  		err = -ENOENT;
  		goto put_err;

  	}

  got_it:

  	if (PageUptodate(page)) {
  		unlock_page(page);

  		return page;

  	}

  	/*
  	 * A new dentry page is allocated but not able to be written, since its
  	 * new inode page couldn't be allocated due to -ENOSPC.
  	 * In such the case, its blkaddr can be remained as NEW_ADDR.
  	 * see, f2fs_add_link -> get_new_data_page -> init_inode_metadata.
  	 */
  	if (dn.data_blkaddr == NEW_ADDR) {

  		zero_user_segment(page, 0, PAGE_SIZE);

  		if (!PageUptodate(page))
  			SetPageUptodate(page);

  		unlock_page(page);

  		return page;
  	}

  	fio.new_blkaddr = fio.old_blkaddr = dn.data_blkaddr;

  	fio.page = page;
  	err = f2fs_submit_page_bio(&fio);

  	if (err)

  		goto put_err;

  	return page;

  
  put_err:
  	f2fs_put_page(page, 1);
  	return ERR_PTR(err);

  }
  
  struct page *find_data_page(struct inode *inode, pgoff_t index)
  {
  	struct address_space *mapping = inode->i_mapping;
  	struct page *page;
  
  	page = find_get_page(mapping, index);
  	if (page && PageUptodate(page))
  		return page;
  	f2fs_put_page(page, 0);

  	page = get_read_data_page(inode, index, READ_SYNC, false);

  	if (IS_ERR(page))
  		return page;
  
  	if (PageUptodate(page))
  		return page;
  
  	wait_on_page_locked(page);
  	if (unlikely(!PageUptodate(page))) {
  		f2fs_put_page(page, 0);
  		return ERR_PTR(-EIO);
  	}
  	return page;
  }
  
  /*
   * If it tries to access a hole, return an error.
   * Because, the callers, functions in dir.c and GC, should be able to know
   * whether this page exists or not.
   */

  struct page *get_lock_data_page(struct inode *inode, pgoff_t index,
  							bool for_write)

  {
  	struct address_space *mapping = inode->i_mapping;
  	struct page *page;
  repeat:

  	page = get_read_data_page(inode, index, READ_SYNC, for_write);

  	if (IS_ERR(page))
  		return page;

  	/* wait for read completion */

  	lock_page(page);

  	if (unlikely(page->mapping != mapping)) {

  		f2fs_put_page(page, 1);
  		goto repeat;

  	}

  	if (unlikely(!PageUptodate(page))) {
  		f2fs_put_page(page, 1);
  		return ERR_PTR(-EIO);
  	}

  	return page;
  }

  /*

   * Caller ensures that this data page is never allocated.
   * A new zero-filled data page is allocated in the page cache.

   *

   * Also, caller should grab and release a rwsem by calling f2fs_lock_op() and
   * f2fs_unlock_op().

   * Note that, ipage is set only by make_empty_dir, and if any error occur,
   * ipage should be released by this function.

   */

  struct page *get_new_data_page(struct inode *inode,

  		struct page *ipage, pgoff_t index, bool new_i_size)

  {

  	struct address_space *mapping = inode->i_mapping;
  	struct page *page;
  	struct dnode_of_data dn;
  	int err;

  	page = f2fs_grab_cache_page(mapping, index, true);

  	if (!page) {
  		/*
  		 * before exiting, we should make sure ipage will be released
  		 * if any error occur.
  		 */
  		f2fs_put_page(ipage, 1);

  		return ERR_PTR(-ENOMEM);

  	}

  	set_new_dnode(&dn, inode, ipage, NULL, 0);

  	err = f2fs_reserve_block(&dn, index);

  	if (err) {
  		f2fs_put_page(page, 1);

  		return ERR_PTR(err);

  	}

  	if (!ipage)
  		f2fs_put_dnode(&dn);

  
  	if (PageUptodate(page))

  		goto got_it;

  
  	if (dn.data_blkaddr == NEW_ADDR) {

  		zero_user_segment(page, 0, PAGE_SIZE);

  		if (!PageUptodate(page))
  			SetPageUptodate(page);

  	} else {

  		f2fs_put_page(page, 1);

  		/* if ipage exists, blkaddr should be NEW_ADDR */
  		f2fs_bug_on(F2FS_I_SB(inode), ipage);
  		page = get_lock_data_page(inode, index, true);

  		if (IS_ERR(page))

  			return page;

  	}

  got_it:

  	if (new_i_size && i_size_read(inode) <

  				((loff_t)(index + 1) << PAGE_SHIFT))

  		f2fs_i_size_write(inode, ((loff_t)(index + 1) << PAGE_SHIFT));

  	return page;
  }

  static int __allocate_data_block(struct dnode_of_data *dn)
  {

  	struct f2fs_sb_info *sbi = F2FS_I_SB(dn->inode);

  	struct f2fs_summary sum;

  	struct node_info ni;

  	int seg = CURSEG_WARM_DATA;

  	pgoff_t fofs;

  	blkcnt_t count = 1;

  	if (unlikely(is_inode_flag_set(dn->inode, FI_NO_ALLOC)))

  		return -EPERM;

  
  	dn->data_blkaddr = datablock_addr(dn->node_page, dn->ofs_in_node);
  	if (dn->data_blkaddr == NEW_ADDR)
  		goto alloc;

  	if (unlikely(!inc_valid_block_count(sbi, dn->inode, &count)))

  		return -ENOSPC;

  alloc:

  	get_node_info(sbi, dn->nid, &ni);
  	set_summary(&sum, dn->nid, dn->ofs_in_node, ni.version);

  	if (dn->ofs_in_node == 0 && dn->inode_page == dn->node_page)
  		seg = CURSEG_DIRECT_IO;

  	allocate_data_block(sbi, NULL, dn->data_blkaddr, &dn->data_blkaddr,
  								&sum, seg);

  	set_data_blkaddr(dn);

  	/* update i_size */

  	fofs = start_bidx_of_node(ofs_of_node(dn->node_page), dn->inode) +

  							dn->ofs_in_node;

  	if (i_size_read(dn->inode) < ((loff_t)(fofs + 1) << PAGE_SHIFT))

  		f2fs_i_size_write(dn->inode,

  				((loff_t)(fofs + 1) << PAGE_SHIFT));

  	return 0;
  }

  ssize_t f2fs_preallocate_blocks(struct kiocb *iocb, struct iov_iter *from)

  {

  	struct inode *inode = file_inode(iocb->ki_filp);

  	struct f2fs_map_blocks map;

  	ssize_t ret = 0;

  	map.m_lblk = F2FS_BLK_ALIGN(iocb->ki_pos);

  	map.m_len = F2FS_BYTES_TO_BLK(iocb->ki_pos + iov_iter_count(from));
  	if (map.m_len > map.m_lblk)
  		map.m_len -= map.m_lblk;
  	else
  		map.m_len = 0;

  	map.m_next_pgofs = NULL;

  	if (iocb->ki_flags & IOCB_DIRECT) {
  		ret = f2fs_convert_inline_inode(inode);
  		if (ret)
  			return ret;
  		return f2fs_map_blocks(inode, &map, 1, F2FS_GET_BLOCK_PRE_DIO);
  	}
  	if (iocb->ki_pos + iov_iter_count(from) > MAX_INLINE_DATA) {

  		ret = f2fs_convert_inline_inode(inode);
  		if (ret)
  			return ret;

  	}

  	if (!f2fs_has_inline_data(inode))
  		return f2fs_map_blocks(inode, &map, 1, F2FS_GET_BLOCK_PRE_AIO);

  	return ret;

  }

  /*

   * f2fs_map_blocks() now supported readahead/bmap/rw direct_IO with
   * f2fs_map_blocks structure.

   * If original data blocks are allocated, then give them to blockdev.
   * Otherwise,
   *     a. preallocate requested block addresses
   *     b. do not use extent cache for better performance
   *     c. give the block addresses to blockdev

   */

  int f2fs_map_blocks(struct inode *inode, struct f2fs_map_blocks *map,

  						int create, int flag)

  {

  	unsigned int maxblocks = map->m_len;

  	struct dnode_of_data dn;

  	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);

  	int mode = create ? ALLOC_NODE : LOOKUP_NODE;

  	pgoff_t pgofs, end_offset, end;

  	int err = 0, ofs = 1;

  	unsigned int ofs_in_node, last_ofs_in_node;
  	blkcnt_t prealloc;

  	struct extent_info ei;

  	bool allocated = false;

  	block_t blkaddr;

  	if (!maxblocks)
  		return 0;

  	map->m_len = 0;
  	map->m_flags = 0;
  
  	/* it only supports block size == page size */
  	pgofs =	(pgoff_t)map->m_lblk;

  	end = pgofs + maxblocks;

  	if (!create && f2fs_lookup_extent_cache(inode, pgofs, &ei)) {

  		map->m_pblk = ei.blk + pgofs - ei.fofs;
  		map->m_len = min((pgoff_t)maxblocks, ei.fofs + ei.len - pgofs);
  		map->m_flags = F2FS_MAP_MAPPED;

  		goto out;

  	}

  next_dnode:

  	if (create)

  		f2fs_lock_op(sbi);

  
  	/* When reading holes, we need its node page */
  	set_new_dnode(&dn, inode, NULL, NULL, 0);

  	err = get_dnode_of_data(&dn, pgofs, mode);

  	if (err) {

  		if (flag == F2FS_GET_BLOCK_BMAP)
  			map->m_pblk = 0;

  		if (err == -ENOENT) {

  			err = 0;

  			if (map->m_next_pgofs)
  				*map->m_next_pgofs =
  					get_next_page_offset(&dn, pgofs);
  		}

  		goto unlock_out;

  	}

  	prealloc = 0;

  	last_ofs_in_node = ofs_in_node = dn.ofs_in_node;

  	end_offset = ADDRS_PER_PAGE(dn.node_page, inode);

  
  next_block:
  	blkaddr = datablock_addr(dn.node_page, dn.ofs_in_node);
  
  	if (blkaddr == NEW_ADDR || blkaddr == NULL_ADDR) {

  		if (create) {

  			if (unlikely(f2fs_cp_error(sbi))) {
  				err = -EIO;

  				goto sync_out;

  			}

  			if (flag == F2FS_GET_BLOCK_PRE_AIO) {

  				if (blkaddr == NULL_ADDR) {
  					prealloc++;
  					last_ofs_in_node = dn.ofs_in_node;
  				}

  			} else {
  				err = __allocate_data_block(&dn);

  				if (!err) {

  					set_inode_flag(inode, FI_APPEND_WRITE);

  					allocated = true;
  				}

  			}

  			if (err)

  				goto sync_out;

  			map->m_flags = F2FS_MAP_NEW;

  			blkaddr = dn.data_blkaddr;

  		} else {

  			if (flag == F2FS_GET_BLOCK_BMAP) {
  				map->m_pblk = 0;
  				goto sync_out;
  			}

  			if (flag == F2FS_GET_BLOCK_FIEMAP &&
  						blkaddr == NULL_ADDR) {
  				if (map->m_next_pgofs)
  					*map->m_next_pgofs = pgofs + 1;
  			}

  			if (flag != F2FS_GET_BLOCK_FIEMAP ||

  						blkaddr != NEW_ADDR)

  				goto sync_out;

  		}

  	}

  	if (flag == F2FS_GET_BLOCK_PRE_AIO)
  		goto skip;

  	if (map->m_len == 0) {
  		/* preallocated unwritten block should be mapped for fiemap. */
  		if (blkaddr == NEW_ADDR)
  			map->m_flags |= F2FS_MAP_UNWRITTEN;
  		map->m_flags |= F2FS_MAP_MAPPED;
  
  		map->m_pblk = blkaddr;
  		map->m_len = 1;
  	} else if ((map->m_pblk != NEW_ADDR &&
  			blkaddr == (map->m_pblk + ofs)) ||

  			(map->m_pblk == NEW_ADDR && blkaddr == NEW_ADDR) ||

  			flag == F2FS_GET_BLOCK_PRE_DIO) {

  		ofs++;
  		map->m_len++;
  	} else {
  		goto sync_out;
  	}

  skip:

  	dn.ofs_in_node++;
  	pgofs++;

  	/* preallocate blocks in batch for one dnode page */
  	if (flag == F2FS_GET_BLOCK_PRE_AIO &&
  			(pgofs == end || dn.ofs_in_node == end_offset)) {

  		dn.ofs_in_node = ofs_in_node;
  		err = reserve_new_blocks(&dn, prealloc);
  		if (err)
  			goto sync_out;

  		allocated = dn.node_changed;

  		map->m_len += dn.ofs_in_node - ofs_in_node;
  		if (prealloc && dn.ofs_in_node != last_ofs_in_node + 1) {
  			err = -ENOSPC;
  			goto sync_out;

  		}

  		dn.ofs_in_node = end_offset;
  	}
  
  	if (pgofs >= end)
  		goto sync_out;
  	else if (dn.ofs_in_node < end_offset)
  		goto next_block;

  	f2fs_put_dnode(&dn);
  
  	if (create) {
  		f2fs_unlock_op(sbi);
  		f2fs_balance_fs(sbi, allocated);

  	}

  	allocated = false;
  	goto next_dnode;

  sync_out:

  	f2fs_put_dnode(&dn);

  unlock_out:

  	if (create) {

  		f2fs_unlock_op(sbi);

  		f2fs_balance_fs(sbi, allocated);

  	}

  out:

  	trace_f2fs_map_blocks(inode, map, err);

  	return err;

  }

  static int __get_data_block(struct inode *inode, sector_t iblock,

  			struct buffer_head *bh, int create, int flag,
  			pgoff_t *next_pgofs)

  {
  	struct f2fs_map_blocks map;
  	int ret;
  
  	map.m_lblk = iblock;
  	map.m_len = bh->b_size >> inode->i_blkbits;

  	map.m_next_pgofs = next_pgofs;

  	ret = f2fs_map_blocks(inode, &map, create, flag);

  	if (!ret) {
  		map_bh(bh, inode->i_sb, map.m_pblk);
  		bh->b_state = (bh->b_state & ~F2FS_MAP_FLAGS) | map.m_flags;
  		bh->b_size = map.m_len << inode->i_blkbits;
  	}
  	return ret;
  }

  static int get_data_block(struct inode *inode, sector_t iblock,

  			struct buffer_head *bh_result, int create, int flag,
  			pgoff_t *next_pgofs)

  {

  	return __get_data_block(inode, iblock, bh_result, create,
  							flag, next_pgofs);

  }
  
  static int get_data_block_dio(struct inode *inode, sector_t iblock,

  			struct buffer_head *bh_result, int create)
  {

  	return __get_data_block(inode, iblock, bh_result, create,

  						F2FS_GET_BLOCK_DIO, NULL);

  }

  static int get_data_block_bmap(struct inode *inode, sector_t iblock,

  			struct buffer_head *bh_result, int create)
  {

  	/* Block number less than F2FS MAX BLOCKS */

  	if (unlikely(iblock >= F2FS_I_SB(inode)->max_file_blocks))

  		return -EFBIG;

  	return __get_data_block(inode, iblock, bh_result, create,

  						F2FS_GET_BLOCK_BMAP, NULL);

  }

  static inline sector_t logical_to_blk(struct inode *inode, loff_t offset)
  {
  	return (offset >> inode->i_blkbits);
  }
  
  static inline loff_t blk_to_logical(struct inode *inode, sector_t blk)
  {
  	return (blk << inode->i_blkbits);
  }

  int f2fs_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
  		u64 start, u64 len)
  {

  	struct buffer_head map_bh;
  	sector_t start_blk, last_blk;

  	pgoff_t next_pgofs;

  	loff_t isize;

  	u64 logical = 0, phys = 0, size = 0;
  	u32 flags = 0;

  	int ret = 0;
  
  	ret = fiemap_check_flags(fieinfo, FIEMAP_FLAG_SYNC);
  	if (ret)
  		return ret;

  	if (f2fs_has_inline_data(inode)) {
  		ret = f2fs_inline_data_fiemap(inode, fieinfo, start, len);
  		if (ret != -EAGAIN)
  			return ret;
  	}

  	inode_lock(inode);

  
  	isize = i_size_read(inode);

  	if (start >= isize)
  		goto out;

  	if (start + len > isize)
  		len = isize - start;

  
  	if (logical_to_blk(inode, len) == 0)
  		len = blk_to_logical(inode, 1);
  
  	start_blk = logical_to_blk(inode, start);
  	last_blk = logical_to_blk(inode, start + len - 1);

  next:
  	memset(&map_bh, 0, sizeof(struct buffer_head));
  	map_bh.b_size = len;

  	ret = get_data_block(inode, start_blk, &map_bh, 0,

  					F2FS_GET_BLOCK_FIEMAP, &next_pgofs);

  	if (ret)
  		goto out;
  
  	/* HOLE */
  	if (!buffer_mapped(&map_bh)) {

  		start_blk = next_pgofs;

  		/* Go through holes util pass the EOF */

  		if (blk_to_logical(inode, start_blk) < isize)

  			goto prep_next;
  		/* Found a hole beyond isize means no more extents.
  		 * Note that the premise is that filesystems don't
  		 * punch holes beyond isize and keep size unchanged.
  		 */
  		flags |= FIEMAP_EXTENT_LAST;
  	}

  	if (size) {
  		if (f2fs_encrypted_inode(inode))
  			flags |= FIEMAP_EXTENT_DATA_ENCRYPTED;

  		ret = fiemap_fill_next_extent(fieinfo, logical,
  				phys, size, flags);

  	}

  	if (start_blk > last_blk || ret)
  		goto out;

  	logical = blk_to_logical(inode, start_blk);
  	phys = blk_to_logical(inode, map_bh.b_blocknr);
  	size = map_bh.b_size;
  	flags = 0;
  	if (buffer_unwritten(&map_bh))
  		flags = FIEMAP_EXTENT_UNWRITTEN;

  	start_blk += logical_to_blk(inode, size);

  prep_next:

  	cond_resched();
  	if (fatal_signal_pending(current))
  		ret = -EINTR;
  	else
  		goto next;
  out:
  	if (ret == 1)
  		ret = 0;

  	inode_unlock(inode);

  	return ret;

  }

  static struct bio *f2fs_grab_bio(struct inode *inode, block_t blkaddr,
  				 unsigned nr_pages)

  {
  	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
  	struct fscrypt_ctx *ctx = NULL;
  	struct block_device *bdev = sbi->sb->s_bdev;
  	struct bio *bio;
  
  	if (f2fs_encrypted_inode(inode) && S_ISREG(inode->i_mode)) {
  		ctx = fscrypt_get_ctx(inode, GFP_NOFS);
  		if (IS_ERR(ctx))
  			return ERR_CAST(ctx);
  
  		/* wait the page to be moved by cleaning */
  		f2fs_wait_on_encrypted_page_writeback(sbi, blkaddr);
  	}
  
  	bio = bio_alloc(GFP_KERNEL, min_t(int, nr_pages, BIO_MAX_PAGES));
  	if (!bio) {
  		if (ctx)
  			fscrypt_release_ctx(ctx);
  		return ERR_PTR(-ENOMEM);
  	}
  	bio->bi_bdev = bdev;
  	bio->bi_iter.bi_sector = SECTOR_FROM_BLOCK(blkaddr);
  	bio->bi_end_io = f2fs_read_end_io;
  	bio->bi_private = ctx;
  
  	return bio;
  }

  /*
   * This function was originally taken from fs/mpage.c, and customized for f2fs.
   * Major change was from block_size == page_size in f2fs by default.
   */
  static int f2fs_mpage_readpages(struct address_space *mapping,
  			struct list_head *pages, struct page *page,
  			unsigned nr_pages)
  {
  	struct bio *bio = NULL;
  	unsigned page_idx;
  	sector_t last_block_in_bio = 0;
  	struct inode *inode = mapping->host;
  	const unsigned blkbits = inode->i_blkbits;
  	const unsigned blocksize = 1 << blkbits;
  	sector_t block_in_file;
  	sector_t last_block;
  	sector_t last_block_in_file;
  	sector_t block_nr;

  	struct f2fs_map_blocks map;
  
  	map.m_pblk = 0;
  	map.m_lblk = 0;
  	map.m_len = 0;
  	map.m_flags = 0;

  	map.m_next_pgofs = NULL;

  
  	for (page_idx = 0; nr_pages; page_idx++, nr_pages--) {
  
  		prefetchw(&page->flags);
  		if (pages) {
  			page = list_entry(pages->prev, struct page, lru);
  			list_del(&page->lru);
  			if (add_to_page_cache_lru(page, mapping,

  						  page->index,
  						  readahead_gfp_mask(mapping)))

  				goto next_page;
  		}
  
  		block_in_file = (sector_t)page->index;
  		last_block = block_in_file + nr_pages;
  		last_block_in_file = (i_size_read(inode) + blocksize - 1) >>
  								blkbits;
  		if (last_block > last_block_in_file)
  			last_block = last_block_in_file;
  
  		/*
  		 * Map blocks using the previous result first.
  		 */
  		if ((map.m_flags & F2FS_MAP_MAPPED) &&
  				block_in_file > map.m_lblk &&
  				block_in_file < (map.m_lblk + map.m_len))
  			goto got_it;
  
  		/*
  		 * Then do more f2fs_map_blocks() calls until we are
  		 * done with this page.
  		 */
  		map.m_flags = 0;
  
  		if (block_in_file < last_block) {
  			map.m_lblk = block_in_file;
  			map.m_len = last_block - block_in_file;

  			if (f2fs_map_blocks(inode, &map, 0,

  						F2FS_GET_BLOCK_READ))

  				goto set_error_page;
  		}
  got_it:
  		if ((map.m_flags & F2FS_MAP_MAPPED)) {
  			block_nr = map.m_pblk + block_in_file - map.m_lblk;
  			SetPageMappedToDisk(page);
  
  			if (!PageUptodate(page) && !cleancache_get_page(page)) {
  				SetPageUptodate(page);
  				goto confused;
  			}
  		} else {

  			zero_user_segment(page, 0, PAGE_SIZE);

  			if (!PageUptodate(page))
  				SetPageUptodate(page);

  			unlock_page(page);
  			goto next_page;
  		}
  
  		/*
  		 * This page will go to BIO.  Do we need to send this
  		 * BIO off first?
  		 */
  		if (bio && (last_block_in_bio != block_nr - 1)) {
  submit_and_realloc:

  			__submit_bio(F2FS_I_SB(inode), bio, DATA);

  			bio = NULL;
  		}
  		if (bio == NULL) {

  			bio = f2fs_grab_bio(inode, block_nr, nr_pages);

  			if (IS_ERR(bio)) {
  				bio = NULL;

  				goto set_error_page;

  			}

  			bio_set_op_attrs(bio, REQ_OP_READ, 0);

  		}
  
  		if (bio_add_page(bio, page, blocksize, 0) < blocksize)
  			goto submit_and_realloc;
  
  		last_block_in_bio = block_nr;
  		goto next_page;
  set_error_page:
  		SetPageError(page);

  		zero_user_segment(page, 0, PAGE_SIZE);

  		unlock_page(page);
  		goto next_page;
  confused:
  		if (bio) {

  			__submit_bio(F2FS_I_SB(inode), bio, DATA);

  			bio = NULL;
  		}
  		unlock_page(page);
  next_page:
  		if (pages)

  			put_page(page);

  	}
  	BUG_ON(pages && !list_empty(pages));
  	if (bio)

  		__submit_bio(F2FS_I_SB(inode), bio, DATA);

  	return 0;
  }

  static int f2fs_read_data_page(struct file *file, struct page *page)
  {

  	struct inode *inode = page->mapping->host;

  	int ret = -EAGAIN;

  	trace_f2fs_readpage(page, DATA);

  	/* If the file has inline data, try to read it directly */

  	if (f2fs_has_inline_data(inode))
  		ret = f2fs_read_inline_data(inode, page);

  	if (ret == -EAGAIN)

  		ret = f2fs_mpage_readpages(page->mapping, NULL, page, 1);

  	return ret;

  }
  
  static int f2fs_read_data_pages(struct file *file,
  			struct address_space *mapping,
  			struct list_head *pages, unsigned nr_pages)
  {

  	struct inode *inode = file->f_mapping->host;

  	struct page *page = list_entry(pages->prev, struct page, lru);
  
  	trace_f2fs_readpages(inode, page, nr_pages);

  
  	/* If the file has inline data, skip readpages */
  	if (f2fs_has_inline_data(inode))
  		return 0;

  	return f2fs_mpage_readpages(mapping, pages, NULL, nr_pages);

  }

  int do_write_data_page(struct f2fs_io_info *fio)

  {

  	struct page *page = fio->page;

  	struct inode *inode = page->mapping->host;

  	struct dnode_of_data dn;
  	int err = 0;
  
  	set_new_dnode(&dn, inode, NULL, NULL, 0);

  	err = get_dnode_of_data(&dn, page->index, LOOKUP_NODE);

  	if (err)
  		return err;

  	fio->old_blkaddr = dn.data_blkaddr;

  
  	/* This page is already truncated */

  	if (fio->old_blkaddr == NULL_ADDR) {

  		ClearPageUptodate(page);

  		goto out_writepage;

  	}

  	if (f2fs_encrypted_inode(inode) && S_ISREG(inode->i_mode)) {

  		gfp_t gfp_flags = GFP_NOFS;

  
  		/* wait for GCed encrypted page writeback */
  		f2fs_wait_on_encrypted_page_writeback(F2FS_I_SB(inode),

  							fio->old_blkaddr);

  retry_encrypt:
  		fio->encrypted_page = fscrypt_encrypt_page(inode, fio->page,
  								gfp_flags);

  		if (IS_ERR(fio->encrypted_page)) {
  			err = PTR_ERR(fio->encrypted_page);

  			if (err == -ENOMEM) {
  				/* flush pending ios and wait for a while */
  				f2fs_flush_merged_bios(F2FS_I_SB(inode));
  				congestion_wait(BLK_RW_ASYNC, HZ/50);
  				gfp_flags |= __GFP_NOFAIL;
  				err = 0;
  				goto retry_encrypt;
  			}

  			goto out_writepage;
  		}
  	}

  	set_page_writeback(page);
  
  	/*
  	 * If current allocation needs SSR,
  	 * it had better in-place writes for updated data.
  	 */

  	if (unlikely(fio->old_blkaddr != NEW_ADDR &&

  			!is_cold_data(page) &&

  			!IS_ATOMIC_WRITTEN_PAGE(page) &&

  			need_inplace_update(inode))) {

  		rewrite_data_page(fio);

  		set_inode_flag(inode, FI_UPDATE_WRITE);

  		trace_f2fs_do_write_data_page(page, IPU);

  	} else {

  		write_data_page(&dn, fio);

  		trace_f2fs_do_write_data_page(page, OPU);

  		set_inode_flag(inode, FI_APPEND_WRITE);

  		if (page->index == 0)

  			set_inode_flag(inode, FI_FIRST_BLOCK_WRITTEN);

  	}
  out_writepage:
  	f2fs_put_dnode(&dn);
  	return err;
  }
  
  static int f2fs_write_data_page(struct page *page,
  					struct writeback_control *wbc)
  {
  	struct inode *inode = page->mapping->host;

  	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);

  	loff_t i_size = i_size_read(inode);
  	const pgoff_t end_index = ((unsigned long long) i_size)

  							>> PAGE_SHIFT;

  	loff_t psize = (page->index + 1) << PAGE_SHIFT;

  	unsigned offset = 0;

  	bool need_balance_fs = false;

  	int err = 0;

  	struct f2fs_io_info fio = {

  		.sbi = sbi,

  		.type = DATA,

  		.op = REQ_OP_WRITE,
  		.op_flags = (wbc->sync_mode == WB_SYNC_ALL) ? WRITE_SYNC : 0,

  		.page = page,

  		.encrypted_page = NULL,

  	};

  	trace_f2fs_writepage(page, DATA);

  	if (page->index < end_index)

  		goto write;

  
  	/*
  	 * If the offset is out-of-range of file size,
  	 * this page does not have to be written to disk.
  	 */

  	offset = i_size & (PAGE_SIZE - 1);

  	if ((page->index >= end_index + 1) || !offset)

  		goto out;

  	zero_user_segment(page, offset, PAGE_SIZE);

  write:

  	if (unlikely(is_sbi_flag_set(sbi, SBI_POR_DOING)))

  		goto redirty_out;

  	if (f2fs_is_drop_cache(inode))
  		goto out;

  	/* we should not write 0'th page having journal header */
  	if (f2fs_is_volatile_file(inode) && (!page->index ||
  			(!wbc->for_reclaim &&
  			available_free_memory(sbi, BASE_CHECK))))

  		goto redirty_out;

  	/* we should bypass data pages to proceed the kworkder jobs */
  	if (unlikely(f2fs_cp_error(sbi))) {

  		mapping_set_error(page->mapping, -EIO);

  		goto out;

  	}

  	/* Dentry blocks are controlled by checkpoint */

  	if (S_ISDIR(inode->i_mode)) {

  		err = do_write_data_page(&fio);

  		goto done;
  	}

  	if (!wbc->for_reclaim)

  		need_balance_fs = true;

  	else if (has_not_enough_free_secs(sbi, 0, 0))

  		goto redirty_out;

  	err = -EAGAIN;

  	f2fs_lock_op(sbi);

  	if (f2fs_has_inline_data(inode))
  		err = f2fs_write_inline_data(inode, page);
  	if (err == -EAGAIN)

  		err = do_write_data_page(&fio);

  	if (F2FS_I(inode)->last_disk_size < psize)
  		F2FS_I(inode)->last_disk_size = psize;

  	f2fs_unlock_op(sbi);
  done:
  	if (err && err != -ENOENT)
  		goto redirty_out;

  	clear_cold_data(page);

  out:

  	inode_dec_dirty_pages(inode);

  	if (err)
  		ClearPageUptodate(page);

  
  	if (wbc->for_reclaim) {
  		f2fs_submit_merged_bio_cond(sbi, NULL, page, 0, DATA, WRITE);
  		remove_dirty_inode(inode);
  	}

  	unlock_page(page);

  	f2fs_balance_fs(sbi, need_balance_fs);

  
  	if (unlikely(f2fs_cp_error(sbi)))

  		f2fs_submit_merged_bio(sbi, DATA, WRITE);

  	return 0;

  redirty_out:

  	redirty_page_for_writepage(wbc, page);

  	unlock_page(page);
  	return err;

  }

  /*
   * This function was copied from write_cche_pages from mm/page-writeback.c.
   * The major change is making write step of cold data page separately from
   * warm/hot data page.
   */
  static int f2fs_write_cache_pages(struct address_space *mapping,

  					struct writeback_control *wbc)

  {
  	int ret = 0;
  	int done = 0;
  	struct pagevec pvec;
  	int nr_pages;
  	pgoff_t uninitialized_var(writeback_index);
  	pgoff_t index;
  	pgoff_t end;		/* Inclusive */
  	pgoff_t done_index;
  	int cycled;
  	int range_whole = 0;
  	int tag;

  	int nwritten = 0;

  
  	pagevec_init(&pvec, 0);

  	if (wbc->range_cyclic) {
  		writeback_index = mapping->writeback_index; /* prev offset */
  		index = writeback_index;
  		if (index == 0)
  			cycled = 1;
  		else
  			cycled = 0;
  		end = -1;
  	} else {

  		index = wbc->range_start >> PAGE_SHIFT;
  		end = wbc->range_end >> PAGE_SHIFT;

  		if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX)
  			range_whole = 1;
  		cycled = 1; /* ignore range_cyclic tests */
  	}
  	if (wbc->sync_mode == WB_SYNC_ALL || wbc->tagged_writepages)
  		tag = PAGECACHE_TAG_TOWRITE;
  	else
  		tag = PAGECACHE_TAG_DIRTY;
  retry:
  	if (wbc->sync_mode == WB_SYNC_ALL || wbc->tagged_writepages)
  		tag_pages_for_writeback(mapping, index, end);
  	done_index = index;
  	while (!done && (index <= end)) {
  		int i;
  
  		nr_pages = pagevec_lookup_tag(&pvec, mapping, &index, tag,
  			      min(end - index, (pgoff_t)PAGEVEC_SIZE - 1) + 1);
  		if (nr_pages == 0)
  			break;
  
  		for (i = 0; i < nr_pages; i++) {
  			struct page *page = pvec.pages[i];
  
  			if (page->index > end) {
  				done = 1;
  				break;
  			}
  
  			done_index = page->index;
  
  			lock_page(page);
  
  			if (unlikely(page->mapping != mapping)) {
  continue_unlock:
  				unlock_page(page);
  				continue;
  			}
  
  			if (!PageDirty(page)) {
  				/* someone wrote it for us */
  				goto continue_unlock;
  			}

  			if (PageWriteback(page)) {
  				if (wbc->sync_mode != WB_SYNC_NONE)

  					f2fs_wait_on_page_writeback(page,
  								DATA, true);

  				else
  					goto continue_unlock;
  			}
  
  			BUG_ON(PageWriteback(page));
  			if (!clear_page_dirty_for_io(page))
  				goto continue_unlock;

  			ret = mapping->a_ops->writepage(page, wbc);

  			if (unlikely(ret)) {

  				done_index = page->index + 1;
  				done = 1;
  				break;

  			} else {
  				nwritten++;

  			}
  
  			if (--wbc->nr_to_write <= 0 &&
  			    wbc->sync_mode == WB_SYNC_NONE) {
  				done = 1;
  				break;
  			}
  		}
  		pagevec_release(&pvec);
  		cond_resched();
  	}

  	if (!cycled && !done) {
  		cycled = 1;
  		index = 0;
  		end = writeback_index - 1;
  		goto retry;
  	}
  	if (wbc->range_cyclic || (range_whole && wbc->nr_to_write > 0))
  		mapping->writeback_index = done_index;

  	if (nwritten)
  		f2fs_submit_merged_bio_cond(F2FS_M_SB(mapping), mapping->host,
  							NULL, 0, DATA, WRITE);

  	return ret;
  }

  static int f2fs_write_data_pages(struct address_space *mapping,