/*
   * Copyright 2000 by Hans Reiser, licensing governed by reiserfs/README
   */

  #include <linux/time.h>

  #include "reiserfs.h"

  #include "acl.h"

  #include "xattr.h"

  #include <linux/uaccess.h>

  #include <linux/pagemap.h>
  #include <linux/swap.h>
  #include <linux/writeback.h>
  #include <linux/blkdev.h>
  #include <linux/buffer_head.h>
  #include <linux/quotaops.h>
  
  /*

   * We pack the tails of files on file close, not at the time they are written.
   * This implies an unnecessary copy of the tail and an unnecessary indirect item
   * insertion/balancing, for files that are written in one write.
   * It avoids unnecessary tail packings (balances) for files that are written in
   * multiple writes and are small enough to have tails.
   *
   * file_release is called by the VFS layer when the file is closed.  If
   * this is the last open file descriptor, and the file
   * small enough to have a tail, and the tail is currently in an
   * unformatted node, the tail is converted back into a direct item.
   *
   * We use reiserfs_truncate_file to pack the tail, since it already has
   * all the conditions coded.
   */

  static int reiserfs_file_release(struct inode *inode, struct file *filp)

  {

  	struct reiserfs_transaction_handle th;
  	int err;
  	int jbegin_failure = 0;

  	BUG_ON(!S_ISREG(inode->i_mode));

          if (atomic_add_unless(&REISERFS_I(inode)->openers, -1, 1))
  		return 0;

  	mutex_lock(&REISERFS_I(inode)->tailpack);

  
          if (!atomic_dec_and_test(&REISERFS_I(inode)->openers)) {

  		mutex_unlock(&REISERFS_I(inode)->tailpack);

  		return 0;
  	}

  	/* fast out for when nothing needs to be done */

  	if ((!(REISERFS_I(inode)->i_flags & i_pack_on_close_mask) ||

  	     !tail_has_to_be_packed(inode)) &&
  	    REISERFS_I(inode)->i_prealloc_count <= 0) {

  		mutex_unlock(&REISERFS_I(inode)->tailpack);

  		return 0;
  	}

  	reiserfs_write_lock(inode->i_sb);

  	/*
  	 * freeing preallocation only involves relogging blocks that

  	 * are already in the current transaction.  preallocation gets
  	 * freed at the end of each transaction, so it is impossible for
  	 * us to log any additional blocks (including quota blocks)
  	 */
  	err = journal_begin(&th, inode->i_sb, 1);

  	if (err) {

  		/*
  		 * uh oh, we can't allow the inode to go away while there

  		 * is still preallocation blocks pending.  Try to join the
  		 * aborted transaction
  		 */
  		jbegin_failure = err;

  		err = journal_join_abort(&th, inode->i_sb);

  
  		if (err) {

  			/*
  			 * hmpf, our choices here aren't good.  We can pin
  			 * the inode which will disallow unmount from ever
  			 * happening, we can do nothing, which will corrupt
  			 * random memory on unmount, or we can forcibly
  			 * remove the file from the preallocation list, which
  			 * will leak blocks on disk.  Lets pin the inode

  			 * and let the admin know what is going on.
  			 */
  			igrab(inode);

  			reiserfs_warning(inode->i_sb, "clm-9001",

  					 "pinning inode %lu because the "

  					 "preallocation can't be freed",
  					 inode->i_ino);

  			goto out;
  		}

  	}

  	reiserfs_update_inode_transaction(inode);

  
  #ifdef REISERFS_PREALLOCATE

  	reiserfs_discard_prealloc(&th, inode);

  #endif

  	err = journal_end(&th);

  
  	/* copy back the error code from journal_begin */
  	if (!err)
  		err = jbegin_failure;

  	if (!err &&

  	    (REISERFS_I(inode)->i_flags & i_pack_on_close_mask) &&
  	    tail_has_to_be_packed(inode)) {

  		/*
  		 * if regular file is released by last holder and it has been
  		 * appended (we append by unformatted node only) or its direct
  		 * item(s) had to be converted, then it may have to be
  		 * indirect2direct converted
  		 */

  		err = reiserfs_truncate_file(inode, 0);
  	}

  out:

  	reiserfs_write_unlock(inode->i_sb);

  	mutex_unlock(&REISERFS_I(inode)->tailpack);

  	return err;

  }

  static int reiserfs_file_open(struct inode *inode, struct file *file)

  {

  	int err = dquot_file_open(inode, file);

  
  	/* somebody might be tailpacking on final close; wait for it */

          if (!atomic_inc_not_zero(&REISERFS_I(inode)->openers)) {

  		mutex_lock(&REISERFS_I(inode)->tailpack);

  		atomic_inc(&REISERFS_I(inode)->openers);

  		mutex_unlock(&REISERFS_I(inode)->tailpack);

  	}
  	return err;

  }

  void reiserfs_vfs_truncate_file(struct inode *inode)

  {

  	mutex_lock(&REISERFS_I(inode)->tailpack);

  	reiserfs_truncate_file(inode, 1);

  	mutex_unlock(&REISERFS_I(inode)->tailpack);

  }
  
  /* Sync a reiserfs file. */
  
  /*
   * FIXME: sync_mapping_buffers() never has anything to sync.  Can
   * be removed...
   */

  static int reiserfs_sync_file(struct file *filp, loff_t start, loff_t end,
  			      int datasync)

  {

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

  	int err;

  	int barrier_done;

  	err = filemap_write_and_wait_range(inode->i_mapping, start, end);
  	if (err)
  		return err;

  	inode_lock(inode);

  	BUG_ON(!S_ISREG(inode->i_mode));

  	err = sync_mapping_buffers(inode->i_mapping);

  	reiserfs_write_lock(inode->i_sb);
  	barrier_done = reiserfs_commit_for_inode(inode);
  	reiserfs_write_unlock(inode->i_sb);
  	if (barrier_done != 1 && reiserfs_barrier_flush(inode->i_sb))

  		blkdev_issue_flush(inode->i_sb->s_bdev, GFP_KERNEL, NULL);

  	inode_unlock(inode);

  	if (barrier_done < 0)
  		return barrier_done;

  	return (err < 0) ? -EIO : 0;

  }

  /* taken fs/buffer.c:__block_commit_write */
  int reiserfs_commit_page(struct inode *inode, struct page *page,

  			 unsigned from, unsigned to)

  {

  	unsigned block_start, block_end;
  	int partial = 0;
  	unsigned blocksize;
  	struct buffer_head *bh, *head;

  	unsigned long i_size_index = inode->i_size >> PAGE_SHIFT;

  	int new;
  	int logit = reiserfs_file_data_log(inode);
  	struct super_block *s = inode->i_sb;

  	int bh_per_page = PAGE_SIZE / s->s_blocksize;

  	struct reiserfs_transaction_handle th;
  	int ret = 0;
  
  	th.t_trans_id = 0;
  	blocksize = 1 << inode->i_blkbits;
  
  	if (logit) {
  		reiserfs_write_lock(s);
  		ret = journal_begin(&th, s, bh_per_page + 1);
  		if (ret)
  			goto drop_write_lock;
  		reiserfs_update_inode_transaction(inode);
  	}
  	for (bh = head = page_buffers(page), block_start = 0;
  	     bh != head || !block_start;
  	     block_start = block_end, bh = bh->b_this_page) {
  
  		new = buffer_new(bh);
  		clear_buffer_new(bh);
  		block_end = block_start + blocksize;
  		if (block_end <= from || block_start >= to) {
  			if (!buffer_uptodate(bh))
  				partial = 1;
  		} else {
  			set_buffer_uptodate(bh);
  			if (logit) {
  				reiserfs_prepare_for_journal(s, bh, 1);

  				journal_mark_dirty(&th, bh);

  			} else if (!buffer_dirty(bh)) {
  				mark_buffer_dirty(bh);

  				/*
  				 * do data=ordered on any page past the end

  				 * of file and any buffer marked BH_New.
  				 */
  				if (reiserfs_data_ordered(inode->i_sb) &&
  				    (new || page->index >= i_size_index)) {
  					reiserfs_add_ordered_list(inode, bh);
  				}
  			}
  		}

  	}

  	if (logit) {

  		ret = journal_end(&th);

  drop_write_lock:

  		reiserfs_write_unlock(s);
  	}
  	/*
  	 * If this is a partial write which happened to make all buffers
  	 * uptodate then we can optimize away a bogus readpage() for
  	 * the next read(). Here we 'discover' whether the page went
  	 * uptodate as a result of this (potentially partial) write.
  	 */
  	if (!partial)
  		SetPageUptodate(page);
  	return ret;

  }

  const struct file_operations reiserfs_file_operations = {

  	.unlocked_ioctl = reiserfs_ioctl,

  #ifdef CONFIG_COMPAT
  	.compat_ioctl = reiserfs_compat_ioctl,
  #endif

  	.mmap = generic_file_mmap,
  	.open = reiserfs_file_open,

  	.release = reiserfs_file_release,
  	.fsync = reiserfs_sync_file,

  	.read_iter = generic_file_read_iter,

  	.write_iter = generic_file_write_iter,

  	.splice_read = generic_file_splice_read,

  	.splice_write = iter_file_splice_write,

  	.llseek = generic_file_llseek,

  };

  const struct inode_operations reiserfs_file_inode_operations = {

  	.setattr = reiserfs_setattr,
  	.setxattr = reiserfs_setxattr,
  	.getxattr = reiserfs_getxattr,
  	.listxattr = reiserfs_listxattr,
  	.removexattr = reiserfs_removexattr,
  	.permission = reiserfs_permission,

  	.get_acl = reiserfs_get_acl,

  	.set_acl = reiserfs_set_acl,

  };