/* -*- mode: c; c-basic-offset: 8; -*-
   * vim: noexpandtab sw=8 ts=8 sts=0:
   *
   * file.c
   *
   * File open, close, extend, truncate
   *
   * Copyright (C) 2002, 2004 Oracle.  All rights reserved.
   *
   * 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., 59 Temple Place - Suite 330,
   * Boston, MA 021110-1307, USA.
   */

  #include <linux/capability.h>

  #include <linux/fs.h>
  #include <linux/types.h>
  #include <linux/slab.h>
  #include <linux/highmem.h>
  #include <linux/pagemap.h>
  #include <linux/uio.h>

  #include <linux/sched.h>

  #include <linux/splice.h>

  #include <linux/mount.h>

  #include <linux/writeback.h>

  #include <linux/falloc.h>

  
  #define MLOG_MASK_PREFIX ML_INODE
  #include <cluster/masklog.h>
  
  #include "ocfs2.h"
  
  #include "alloc.h"
  #include "aops.h"
  #include "dir.h"
  #include "dlmglue.h"
  #include "extent_map.h"
  #include "file.h"
  #include "sysfile.h"
  #include "inode.h"

  #include "ioctl.h"

  #include "journal.h"
  #include "mmap.h"
  #include "suballoc.h"
  #include "super.h"
  
  #include "buffer_head_io.h"
  
  static int ocfs2_sync_inode(struct inode *inode)
  {
  	filemap_fdatawrite(inode->i_mapping);
  	return sync_mapping_buffers(inode->i_mapping);
  }
  
  static int ocfs2_file_open(struct inode *inode, struct file *file)
  {
  	int status;
  	int mode = file->f_flags;
  	struct ocfs2_inode_info *oi = OCFS2_I(inode);
  
  	mlog_entry("(0x%p, 0x%p, '%.*s')
  ", inode, file,

  		   file->f_path.dentry->d_name.len, file->f_path.dentry->d_name.name);

  
  	spin_lock(&oi->ip_lock);
  
  	/* Check that the inode hasn't been wiped from disk by another
  	 * node. If it hasn't then we're safe as long as we hold the
  	 * spin lock until our increment of open count. */
  	if (OCFS2_I(inode)->ip_flags & OCFS2_INODE_DELETED) {
  		spin_unlock(&oi->ip_lock);
  
  		status = -ENOENT;
  		goto leave;
  	}
  
  	if (mode & O_DIRECT)
  		oi->ip_flags |= OCFS2_INODE_OPEN_DIRECT;
  
  	oi->ip_open_count++;
  	spin_unlock(&oi->ip_lock);
  	status = 0;
  leave:
  	mlog_exit(status);
  	return status;
  }
  
  static int ocfs2_file_release(struct inode *inode, struct file *file)
  {
  	struct ocfs2_inode_info *oi = OCFS2_I(inode);
  
  	mlog_entry("(0x%p, 0x%p, '%.*s')
  ", inode, file,

  		       file->f_path.dentry->d_name.len,
  		       file->f_path.dentry->d_name.name);

  
  	spin_lock(&oi->ip_lock);
  	if (!--oi->ip_open_count)
  		oi->ip_flags &= ~OCFS2_INODE_OPEN_DIRECT;
  	spin_unlock(&oi->ip_lock);
  
  	mlog_exit(0);
  
  	return 0;
  }
  
  static int ocfs2_sync_file(struct file *file,
  			   struct dentry *dentry,
  			   int datasync)
  {
  	int err = 0;
  	journal_t *journal;
  	struct inode *inode = dentry->d_inode;
  	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
  
  	mlog_entry("(0x%p, 0x%p, %d, '%.*s')
  ", file, dentry, datasync,
  		   dentry->d_name.len, dentry->d_name.name);
  
  	err = ocfs2_sync_inode(dentry->d_inode);
  	if (err)
  		goto bail;
  
  	journal = osb->journal->j_journal;
  	err = journal_force_commit(journal);
  
  bail:
  	mlog_exit(err);
  
  	return (err < 0) ? -EIO : 0;
  }

  int ocfs2_should_update_atime(struct inode *inode,
  			      struct vfsmount *vfsmnt)
  {
  	struct timespec now;
  	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
  
  	if (ocfs2_is_hard_readonly(osb) || ocfs2_is_soft_readonly(osb))
  		return 0;
  
  	if ((inode->i_flags & S_NOATIME) ||
  	    ((inode->i_sb->s_flags & MS_NODIRATIME) && S_ISDIR(inode->i_mode)))
  		return 0;

  	/*
  	 * We can be called with no vfsmnt structure - NFSD will
  	 * sometimes do this.
  	 *
  	 * Note that our action here is different than touch_atime() -
  	 * if we can't tell whether this is a noatime mount, then we
  	 * don't know whether to trust the value of s_atime_quantum.
  	 */
  	if (vfsmnt == NULL)
  		return 0;

  	if ((vfsmnt->mnt_flags & MNT_NOATIME) ||
  	    ((vfsmnt->mnt_flags & MNT_NODIRATIME) && S_ISDIR(inode->i_mode)))
  		return 0;

  	if (vfsmnt->mnt_flags & MNT_RELATIME) {
  		if ((timespec_compare(&inode->i_atime, &inode->i_mtime) <= 0) ||
  		    (timespec_compare(&inode->i_atime, &inode->i_ctime) <= 0))
  			return 1;
  
  		return 0;
  	}

  	now = CURRENT_TIME;
  	if ((now.tv_sec - inode->i_atime.tv_sec <= osb->s_atime_quantum))
  		return 0;
  	else
  		return 1;
  }
  
  int ocfs2_update_inode_atime(struct inode *inode,
  			     struct buffer_head *bh)
  {
  	int ret;
  	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
  	handle_t *handle;
  
  	mlog_entry_void();
  
  	handle = ocfs2_start_trans(osb, OCFS2_INODE_UPDATE_CREDITS);
  	if (handle == NULL) {
  		ret = -ENOMEM;
  		mlog_errno(ret);
  		goto out;
  	}
  
  	inode->i_atime = CURRENT_TIME;
  	ret = ocfs2_mark_inode_dirty(handle, inode, bh);
  	if (ret < 0)
  		mlog_errno(ret);
  
  	ocfs2_commit_trans(OCFS2_SB(inode->i_sb), handle);
  out:
  	mlog_exit(ret);
  	return ret;
  }

  static int ocfs2_set_inode_size(handle_t *handle,
  				struct inode *inode,
  				struct buffer_head *fe_bh,
  				u64 new_i_size)

  {
  	int status;
  
  	mlog_entry_void();
  	i_size_write(inode, new_i_size);

  	inode->i_blocks = ocfs2_inode_sector_count(inode);

  	inode->i_ctime = inode->i_mtime = CURRENT_TIME;
  
  	status = ocfs2_mark_inode_dirty(handle, inode, fe_bh);
  	if (status < 0) {
  		mlog_errno(status);
  		goto bail;
  	}
  
  bail:
  	mlog_exit(status);
  	return status;
  }
  
  static int ocfs2_simple_size_update(struct inode *inode,
  				    struct buffer_head *di_bh,
  				    u64 new_i_size)
  {
  	int ret;
  	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);

  	handle_t *handle = NULL;

  	handle = ocfs2_start_trans(osb, OCFS2_INODE_UPDATE_CREDITS);

  	if (handle == NULL) {
  		ret = -ENOMEM;
  		mlog_errno(ret);
  		goto out;
  	}
  
  	ret = ocfs2_set_inode_size(handle, inode, di_bh,
  				   new_i_size);
  	if (ret < 0)
  		mlog_errno(ret);

  	ocfs2_commit_trans(osb, handle);

  out:
  	return ret;
  }
  
  static int ocfs2_orphan_for_truncate(struct ocfs2_super *osb,
  				     struct inode *inode,
  				     struct buffer_head *fe_bh,
  				     u64 new_i_size)
  {
  	int status;

  	handle_t *handle;

  	struct ocfs2_dinode *di;

  	u64 cluster_bytes;

  
  	mlog_entry_void();
  
  	/* TODO: This needs to actually orphan the inode in this
  	 * transaction. */

  	handle = ocfs2_start_trans(osb, OCFS2_INODE_UPDATE_CREDITS);

  	if (IS_ERR(handle)) {
  		status = PTR_ERR(handle);
  		mlog_errno(status);
  		goto out;
  	}

  	status = ocfs2_journal_access(handle, inode, fe_bh,
  				      OCFS2_JOURNAL_ACCESS_WRITE);
  	if (status < 0) {
  		mlog_errno(status);
  		goto out_commit;
  	}
  
  	/*
  	 * Do this before setting i_size.
  	 */

  	cluster_bytes = ocfs2_align_bytes_to_clusters(inode->i_sb, new_i_size);
  	status = ocfs2_zero_range_for_truncate(inode, handle, new_i_size,
  					       cluster_bytes);

  	if (status) {
  		mlog_errno(status);
  		goto out_commit;
  	}
  
  	i_size_write(inode, new_i_size);
  	inode->i_blocks = ocfs2_align_bytes_to_sectors(new_i_size);
  	inode->i_ctime = inode->i_mtime = CURRENT_TIME;
  
  	di = (struct ocfs2_dinode *) fe_bh->b_data;
  	di->i_size = cpu_to_le64(new_i_size);
  	di->i_ctime = di->i_mtime = cpu_to_le64(inode->i_ctime.tv_sec);
  	di->i_ctime_nsec = di->i_mtime_nsec = cpu_to_le32(inode->i_ctime.tv_nsec);
  
  	status = ocfs2_journal_dirty(handle, fe_bh);

  	if (status < 0)
  		mlog_errno(status);

  out_commit:

  	ocfs2_commit_trans(osb, handle);

  out:

  	mlog_exit(status);
  	return status;
  }
  
  static int ocfs2_truncate_file(struct inode *inode,
  			       struct buffer_head *di_bh,
  			       u64 new_i_size)
  {
  	int status = 0;
  	struct ocfs2_dinode *fe = NULL;
  	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
  	struct ocfs2_truncate_context *tc = NULL;

  	mlog_entry("(inode = %llu, new_i_size = %llu
  ",
  		   (unsigned long long)OCFS2_I(inode)->ip_blkno,
  		   (unsigned long long)new_i_size);

  	fe = (struct ocfs2_dinode *) di_bh->b_data;
  	if (!OCFS2_IS_VALID_DINODE(fe)) {
  		OCFS2_RO_ON_INVALID_DINODE(inode->i_sb, fe);
  		status = -EIO;
  		goto bail;
  	}
  
  	mlog_bug_on_msg(le64_to_cpu(fe->i_size) != i_size_read(inode),

  			"Inode %llu, inode i_size = %lld != di "
  			"i_size = %llu, i_flags = 0x%x
  ",
  			(unsigned long long)OCFS2_I(inode)->ip_blkno,

  			i_size_read(inode),

  			(unsigned long long)le64_to_cpu(fe->i_size),
  			le32_to_cpu(fe->i_flags));

  
  	if (new_i_size > le64_to_cpu(fe->i_size)) {

  		mlog(0, "asked to truncate file with size (%llu) to size (%llu)!
  ",
  		     (unsigned long long)le64_to_cpu(fe->i_size),
  		     (unsigned long long)new_i_size);

  		status = -EINVAL;
  		mlog_errno(status);
  		goto bail;
  	}

  	mlog(0, "inode %llu, i_size = %llu, new_i_size = %llu
  ",
  	     (unsigned long long)le64_to_cpu(fe->i_blkno),
  	     (unsigned long long)le64_to_cpu(fe->i_size),
  	     (unsigned long long)new_i_size);

  
  	/* lets handle the simple truncate cases before doing any more
  	 * cluster locking. */
  	if (new_i_size == le64_to_cpu(fe->i_size))
  		goto bail;

  	down_write(&OCFS2_I(inode)->ip_alloc_sem);

  	/* This forces other nodes to sync and drop their pages. Do
  	 * this even if we have a truncate without allocation change -
  	 * ocfs2 cluster sizes can be much greater than page size, so
  	 * we have to truncate them anyway.  */
  	status = ocfs2_data_lock(inode, 1);
  	if (status < 0) {

  		up_write(&OCFS2_I(inode)->ip_alloc_sem);

  		mlog_errno(status);
  		goto bail;
  	}

  	unmap_mapping_range(inode->i_mapping, new_i_size + PAGE_SIZE - 1, 0, 1);
  	truncate_inode_pages(inode->i_mapping, new_i_size);

  	/* alright, we're going to need to do a full blown alloc size
  	 * change. Orphan the inode so that recovery can complete the
  	 * truncate if necessary. This does the task of marking
  	 * i_size. */
  	status = ocfs2_orphan_for_truncate(osb, inode, di_bh, new_i_size);
  	if (status < 0) {
  		mlog_errno(status);

  		goto bail_unlock_data;

  	}
  
  	status = ocfs2_prepare_truncate(osb, inode, di_bh, &tc);
  	if (status < 0) {
  		mlog_errno(status);

  		goto bail_unlock_data;

  	}
  
  	status = ocfs2_commit_truncate(osb, inode, di_bh, tc);
  	if (status < 0) {
  		mlog_errno(status);

  		goto bail_unlock_data;

  	}
  
  	/* TODO: orphan dir cleanup here. */

  bail_unlock_data:
  	ocfs2_data_unlock(inode, 1);

  	up_write(&OCFS2_I(inode)->ip_alloc_sem);

  bail:
  
  	mlog_exit(status);
  	return status;
  }
  
  /*
   * extend allocation only here.
   * we'll update all the disk stuff, and oip->alloc_size
   *
   * expect stuff to be locked, a transaction started and enough data /
   * metadata reservations in the contexts.
   *
   * Will return -EAGAIN, and a reason if a restart is needed.
   * If passed in, *reason will always be set, even in error.
   */
  int ocfs2_do_extend_allocation(struct ocfs2_super *osb,
  			       struct inode *inode,

  			       u32 *logical_offset,

  			       u32 clusters_to_add,

  			       int mark_unwritten,

  			       struct buffer_head *fe_bh,

  			       handle_t *handle,

  			       struct ocfs2_alloc_context *data_ac,
  			       struct ocfs2_alloc_context *meta_ac,
  			       enum ocfs2_alloc_restarted *reason_ret)
  {
  	int status = 0;
  	int free_extents;
  	struct ocfs2_dinode *fe = (struct ocfs2_dinode *) fe_bh->b_data;
  	enum ocfs2_alloc_restarted reason = RESTART_NONE;
  	u32 bit_off, num_bits;
  	u64 block;

  	u8 flags = 0;

  
  	BUG_ON(!clusters_to_add);

  	if (mark_unwritten)
  		flags = OCFS2_EXT_UNWRITTEN;

  	free_extents = ocfs2_num_free_extents(osb, inode, fe);
  	if (free_extents < 0) {
  		status = free_extents;
  		mlog_errno(status);
  		goto leave;
  	}
  
  	/* there are two cases which could cause us to EAGAIN in the
  	 * we-need-more-metadata case:
  	 * 1) we haven't reserved *any*
  	 * 2) we are so fragmented, we've needed to add metadata too
  	 *    many times. */
  	if (!free_extents && !meta_ac) {
  		mlog(0, "we haven't reserved any metadata!
  ");
  		status = -EAGAIN;
  		reason = RESTART_META;
  		goto leave;
  	} else if ((!free_extents)
  		   && (ocfs2_alloc_context_bits_left(meta_ac)
  		       < ocfs2_extend_meta_needed(fe))) {
  		mlog(0, "filesystem is really fragmented...
  ");
  		status = -EAGAIN;
  		reason = RESTART_META;
  		goto leave;
  	}
  
  	status = ocfs2_claim_clusters(osb, handle, data_ac, 1,
  				      &bit_off, &num_bits);
  	if (status < 0) {
  		if (status != -ENOSPC)
  			mlog_errno(status);
  		goto leave;
  	}
  
  	BUG_ON(num_bits > clusters_to_add);
  
  	/* reserve our write early -- insert_extent may update the inode */
  	status = ocfs2_journal_access(handle, inode, fe_bh,
  				      OCFS2_JOURNAL_ACCESS_WRITE);
  	if (status < 0) {
  		mlog_errno(status);
  		goto leave;
  	}
  
  	block = ocfs2_clusters_to_blocks(osb->sb, bit_off);

  	mlog(0, "Allocating %u clusters at block %u for inode %llu
  ",
  	     num_bits, bit_off, (unsigned long long)OCFS2_I(inode)->ip_blkno);

  	status = ocfs2_insert_extent(osb, handle, inode, fe_bh,
  				     *logical_offset, block, num_bits,

  				     flags, meta_ac);

  	if (status < 0) {
  		mlog_errno(status);
  		goto leave;
  	}

  	status = ocfs2_journal_dirty(handle, fe_bh);
  	if (status < 0) {
  		mlog_errno(status);
  		goto leave;
  	}
  
  	clusters_to_add -= num_bits;

  	*logical_offset += num_bits;

  
  	if (clusters_to_add) {
  		mlog(0, "need to alloc once more, clusters = %u, wanted = "
  		     "%u
  ", fe->i_clusters, clusters_to_add);
  		status = -EAGAIN;
  		reason = RESTART_TRANS;
  	}
  
  leave:
  	mlog_exit(status);
  	if (reason_ret)
  		*reason_ret = reason;
  	return status;
  }

  /*
   * For a given allocation, determine which allocators will need to be
   * accessed, and lock them, reserving the appropriate number of bits.
   *

   * Sparse file systems call this from ocfs2_write_begin_nolock()
   * and ocfs2_allocate_unwritten_extents().
   *
   * File systems which don't support holes call this from
   * ocfs2_extend_allocation().

   */

  int ocfs2_lock_allocators(struct inode *inode, struct ocfs2_dinode *di,

  			  u32 clusters_to_add, u32 extents_to_split,

  			  struct ocfs2_alloc_context **data_ac,
  			  struct ocfs2_alloc_context **meta_ac)

  {

  	int ret = 0, num_free_extents;

  	unsigned int max_recs_needed = clusters_to_add + 2 * extents_to_split;

  	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
  
  	*meta_ac = NULL;

  	if (data_ac)
  		*data_ac = NULL;
  
  	BUG_ON(clusters_to_add != 0 && data_ac == NULL);

  
  	mlog(0, "extend inode %llu, i_size = %lld, di->i_clusters = %u, "

  	     "clusters_to_add = %u, extents_to_split = %u
  ",

  	     (unsigned long long)OCFS2_I(inode)->ip_blkno, i_size_read(inode),

  	     le32_to_cpu(di->i_clusters), clusters_to_add, extents_to_split);

  
  	num_free_extents = ocfs2_num_free_extents(osb, inode, di);
  	if (num_free_extents < 0) {
  		ret = num_free_extents;
  		mlog_errno(ret);
  		goto out;
  	}
  
  	/*
  	 * Sparse allocation file systems need to be more conservative
  	 * with reserving room for expansion - the actual allocation
  	 * happens while we've got a journal handle open so re-taking
  	 * a cluster lock (because we ran out of room for another
  	 * extent) will violate ordering rules.
  	 *

  	 * Most of the time we'll only be seeing this 1 cluster at a time

  	 * anyway.

  	 *
  	 * Always lock for any unwritten extents - we might want to
  	 * add blocks during a split.

  	 */
  	if (!num_free_extents ||

  	    (ocfs2_sparse_alloc(osb) && num_free_extents < max_recs_needed)) {

  		ret = ocfs2_reserve_new_metadata(osb, di, meta_ac);
  		if (ret < 0) {
  			if (ret != -ENOSPC)
  				mlog_errno(ret);
  			goto out;
  		}
  	}

  	if (clusters_to_add == 0)
  		goto out;

  	ret = ocfs2_reserve_clusters(osb, clusters_to_add, data_ac);
  	if (ret < 0) {
  		if (ret != -ENOSPC)
  			mlog_errno(ret);
  		goto out;
  	}
  
  out:
  	if (ret) {
  		if (*meta_ac) {
  			ocfs2_free_alloc_context(*meta_ac);
  			*meta_ac = NULL;
  		}
  
  		/*
  		 * We cannot have an error and a non null *data_ac.
  		 */
  	}
  
  	return ret;
  }

  static int __ocfs2_extend_allocation(struct inode *inode, u32 logical_start,
  				     u32 clusters_to_add, int mark_unwritten)

  {
  	int status = 0;
  	int restart_func = 0;

  	int credits;

  	u32 prev_clusters;

  	struct buffer_head *bh = NULL;
  	struct ocfs2_dinode *fe = NULL;

  	handle_t *handle = NULL;

  	struct ocfs2_alloc_context *data_ac = NULL;
  	struct ocfs2_alloc_context *meta_ac = NULL;
  	enum ocfs2_alloc_restarted why;
  	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
  
  	mlog_entry("(clusters_to_add = %u)
  ", clusters_to_add);

  	/*
  	 * This function only exists for file systems which don't
  	 * support holes.
  	 */

  	BUG_ON(mark_unwritten && !ocfs2_sparse_alloc(osb));

  	status = ocfs2_read_block(osb, OCFS2_I(inode)->ip_blkno, &bh,
  				  OCFS2_BH_CACHED, inode);
  	if (status < 0) {
  		mlog_errno(status);
  		goto leave;
  	}
  
  	fe = (struct ocfs2_dinode *) bh->b_data;
  	if (!OCFS2_IS_VALID_DINODE(fe)) {
  		OCFS2_RO_ON_INVALID_DINODE(inode->i_sb, fe);
  		status = -EIO;
  		goto leave;
  	}
  
  restart_all:
  	BUG_ON(le32_to_cpu(fe->i_clusters) != OCFS2_I(inode)->ip_clusters);

  	status = ocfs2_lock_allocators(inode, fe, clusters_to_add, 0, &data_ac,

  				       &meta_ac);
  	if (status) {
  		mlog_errno(status);
  		goto leave;
  	}

  	credits = ocfs2_calc_extend_credits(osb->sb, fe, clusters_to_add);

  	handle = ocfs2_start_trans(osb, credits);

  	if (IS_ERR(handle)) {
  		status = PTR_ERR(handle);
  		handle = NULL;
  		mlog_errno(status);
  		goto leave;
  	}
  
  restarted_transaction:
  	/* reserve a write to the file entry early on - that we if we
  	 * run out of credits in the allocation path, we can still
  	 * update i_size. */
  	status = ocfs2_journal_access(handle, inode, bh,
  				      OCFS2_JOURNAL_ACCESS_WRITE);
  	if (status < 0) {
  		mlog_errno(status);
  		goto leave;
  	}
  
  	prev_clusters = OCFS2_I(inode)->ip_clusters;
  
  	status = ocfs2_do_extend_allocation(osb,
  					    inode,

  					    &logical_start,

  					    clusters_to_add,

  					    mark_unwritten,

  					    bh,
  					    handle,
  					    data_ac,
  					    meta_ac,
  					    &why);
  	if ((status < 0) && (status != -EAGAIN)) {
  		if (status != -ENOSPC)
  			mlog_errno(status);
  		goto leave;
  	}
  
  	status = ocfs2_journal_dirty(handle, bh);
  	if (status < 0) {
  		mlog_errno(status);
  		goto leave;
  	}
  
  	spin_lock(&OCFS2_I(inode)->ip_lock);
  	clusters_to_add -= (OCFS2_I(inode)->ip_clusters - prev_clusters);
  	spin_unlock(&OCFS2_I(inode)->ip_lock);
  
  	if (why != RESTART_NONE && clusters_to_add) {
  		if (why == RESTART_META) {
  			mlog(0, "restarting function.
  ");
  			restart_func = 1;
  		} else {
  			BUG_ON(why != RESTART_TRANS);
  
  			mlog(0, "restarting transaction.
  ");
  			/* TODO: This can be more intelligent. */
  			credits = ocfs2_calc_extend_credits(osb->sb,
  							    fe,
  							    clusters_to_add);

  			status = ocfs2_extend_trans(handle, credits);

  			if (status < 0) {
  				/* handle still has to be committed at
  				 * this point. */
  				status = -ENOMEM;
  				mlog_errno(status);
  				goto leave;
  			}
  			goto restarted_transaction;
  		}
  	}

  	mlog(0, "fe: i_clusters = %u, i_size=%llu
  ",

  	     le32_to_cpu(fe->i_clusters),
  	     (unsigned long long)le64_to_cpu(fe->i_size));

  	mlog(0, "inode: ip_clusters=%u, i_size=%lld
  ",
  	     OCFS2_I(inode)->ip_clusters, i_size_read(inode));
  
  leave:

  	if (handle) {

  		ocfs2_commit_trans(osb, handle);

  		handle = NULL;
  	}
  	if (data_ac) {
  		ocfs2_free_alloc_context(data_ac);
  		data_ac = NULL;
  	}
  	if (meta_ac) {
  		ocfs2_free_alloc_context(meta_ac);
  		meta_ac = NULL;
  	}
  	if ((!status) && restart_func) {
  		restart_func = 0;
  		goto restart_all;
  	}
  	if (bh) {
  		brelse(bh);
  		bh = NULL;
  	}
  
  	mlog_exit(status);
  	return status;
  }

  static int ocfs2_extend_allocation(struct inode *inode, u32 logical_start,
  				   u32 clusters_to_add, int mark_unwritten)
  {
  	int ret;
  
  	/*
  	 * The alloc sem blocks peope in read/write from reading our
  	 * allocation until we're done changing it. We depend on
  	 * i_mutex to block other extend/truncate calls while we're
  	 * here.
  	 */
  	down_write(&OCFS2_I(inode)->ip_alloc_sem);
  	ret = __ocfs2_extend_allocation(inode, logical_start, clusters_to_add,
  					mark_unwritten);
  	up_write(&OCFS2_I(inode)->ip_alloc_sem);
  
  	return ret;
  }

  /* Some parts of this taken from generic_cont_expand, which turned out
   * to be too fragile to do exactly what we need without us having to

   * worry about recursive locking in ->prepare_write() and
   * ->commit_write(). */

  static int ocfs2_write_zero_page(struct inode *inode,
  				 u64 size)
  {
  	struct address_space *mapping = inode->i_mapping;
  	struct page *page;
  	unsigned long index;
  	unsigned int offset;

  	handle_t *handle = NULL;

  	int ret;
  
  	offset = (size & (PAGE_CACHE_SIZE-1)); /* Within page */
  	/* ugh.  in prepare/commit_write, if from==to==start of block, we 
  	** skip the prepare.  make sure we never send an offset for the start
  	** of a block
  	*/
  	if ((offset & (inode->i_sb->s_blocksize - 1)) == 0) {
  		offset++;
  	}
  	index = size >> PAGE_CACHE_SHIFT;
  
  	page = grab_cache_page(mapping, index);
  	if (!page) {
  		ret = -ENOMEM;
  		mlog_errno(ret);
  		goto out;
  	}

  	ret = ocfs2_prepare_write_nolock(inode, page, offset, offset);

  	if (ret < 0) {
  		mlog_errno(ret);
  		goto out_unlock;
  	}
  
  	if (ocfs2_should_order_data(inode)) {
  		handle = ocfs2_start_walk_page_trans(inode, page, offset,
  						     offset);
  		if (IS_ERR(handle)) {
  			ret = PTR_ERR(handle);
  			handle = NULL;
  			goto out_unlock;
  		}
  	}
  
  	/* must not update i_size! */
  	ret = block_commit_write(page, offset, offset);
  	if (ret < 0)
  		mlog_errno(ret);
  	else
  		ret = 0;
  
  	if (handle)

  		ocfs2_commit_trans(OCFS2_SB(inode->i_sb), handle);

  out_unlock:
  	unlock_page(page);
  	page_cache_release(page);
  out:
  	return ret;
  }
  
  static int ocfs2_zero_extend(struct inode *inode,
  			     u64 zero_to_size)
  {
  	int ret = 0;
  	u64 start_off;
  	struct super_block *sb = inode->i_sb;
  
  	start_off = ocfs2_align_bytes_to_blocks(sb, i_size_read(inode));
  	while (start_off < zero_to_size) {
  		ret = ocfs2_write_zero_page(inode, start_off);
  		if (ret < 0) {
  			mlog_errno(ret);
  			goto out;
  		}
  
  		start_off += sb->s_blocksize;

  
  		/*
  		 * Very large extends have the potential to lock up
  		 * the cpu for extended periods of time.
  		 */
  		cond_resched();

  	}
  
  out:
  	return ret;
  }

  /* 
   * A tail_to_skip value > 0 indicates that we're being called from
   * ocfs2_file_aio_write(). This has the following implications:
   *
   * - we don't want to update i_size
   * - di_bh will be NULL, which is fine because it's only used in the
   *   case where we want to update i_size.
   * - ocfs2_zero_extend() will then only be filling the hole created
   *   between i_size and the start of the write.
   */

  static int ocfs2_extend_file(struct inode *inode,
  			     struct buffer_head *di_bh,

  			     u64 new_i_size,
  			     size_t tail_to_skip)

  {
  	int ret = 0;

  	u32 clusters_to_add = 0;

  	BUG_ON(!tail_to_skip && !di_bh);

  	/* setattr sometimes calls us like this. */
  	if (new_i_size == 0)
  		goto out;
  
  	if (i_size_read(inode) == new_i_size)
    		goto out;
  	BUG_ON(new_i_size < i_size_read(inode));

  	if (ocfs2_sparse_alloc(OCFS2_SB(inode->i_sb))) {
  		BUG_ON(tail_to_skip != 0);
  		goto out_update_size;
  	}

  	clusters_to_add = ocfs2_clusters_for_bytes(inode->i_sb, new_i_size) - 
  		OCFS2_I(inode)->ip_clusters;

  	/* 
  	 * protect the pages that ocfs2_zero_extend is going to be
  	 * pulling into the page cache.. we do this before the
  	 * metadata extend so that we don't get into the situation
  	 * where we've extended the metadata but can't get the data
  	 * lock to zero.
  	 */
  	ret = ocfs2_data_lock(inode, 1);
  	if (ret < 0) {
  		mlog_errno(ret);
  		goto out;
  	}

  	if (clusters_to_add) {

  		ret = ocfs2_extend_allocation(inode,
  					      OCFS2_I(inode)->ip_clusters,
  					      clusters_to_add, 0);

  		if (ret < 0) {
  			mlog_errno(ret);

  			goto out_unlock;

  		}

  	}

  	/*
  	 * Call this even if we don't add any clusters to the tree. We
  	 * still need to zero the area between the old i_size and the
  	 * new i_size.
  	 */
  	ret = ocfs2_zero_extend(inode, (u64)new_i_size - tail_to_skip);
  	if (ret < 0) {
  		mlog_errno(ret);
  		goto out_unlock;

  	}

  out_update_size:

  	if (!tail_to_skip) {
  		/* We're being called from ocfs2_setattr() which wants
  		 * us to update i_size */
  		ret = ocfs2_simple_size_update(inode, di_bh, new_i_size);
  		if (ret < 0)
  			mlog_errno(ret);

  	}

  out_unlock:

  	if (!ocfs2_sparse_alloc(OCFS2_SB(inode->i_sb)))
  		ocfs2_data_unlock(inode, 1);

  out:
  	return ret;
  }
  
  int ocfs2_setattr(struct dentry *dentry, struct iattr *attr)
  {
  	int status = 0, size_change;
  	struct inode *inode = dentry->d_inode;
  	struct super_block *sb = inode->i_sb;
  	struct ocfs2_super *osb = OCFS2_SB(sb);
  	struct buffer_head *bh = NULL;

  	handle_t *handle = NULL;

  
  	mlog_entry("(0x%p, '%.*s')
  ", dentry,
  	           dentry->d_name.len, dentry->d_name.name);
  
  	if (attr->ia_valid & ATTR_MODE)
  		mlog(0, "mode change: %d
  ", attr->ia_mode);
  	if (attr->ia_valid & ATTR_UID)
  		mlog(0, "uid change: %d
  ", attr->ia_uid);
  	if (attr->ia_valid & ATTR_GID)
  		mlog(0, "gid change: %d
  ", attr->ia_gid);
  	if (attr->ia_valid & ATTR_SIZE)
  		mlog(0, "size change...
  ");
  	if (attr->ia_valid & (ATTR_ATIME | ATTR_MTIME | ATTR_CTIME))
  		mlog(0, "time change...
  ");
  
  #define OCFS2_VALID_ATTRS (ATTR_ATIME | ATTR_MTIME | ATTR_CTIME | ATTR_SIZE \
  			   | ATTR_GID | ATTR_UID | ATTR_MODE)
  	if (!(attr->ia_valid & OCFS2_VALID_ATTRS)) {
  		mlog(0, "can't handle attrs: 0x%x
  ", attr->ia_valid);
  		return 0;
  	}
  
  	status = inode_change_ok(inode, attr);
  	if (status)
  		return status;
  
  	size_change = S_ISREG(inode->i_mode) && attr->ia_valid & ATTR_SIZE;
  	if (size_change) {
  		status = ocfs2_rw_lock(inode, 1);
  		if (status < 0) {
  			mlog_errno(status);
  			goto bail;
  		}
  	}

  	status = ocfs2_meta_lock(inode, &bh, 1);

  	if (status < 0) {
  		if (status != -ENOENT)
  			mlog_errno(status);
  		goto bail_unlock_rw;
  	}
  
  	if (size_change && attr->ia_size != i_size_read(inode)) {
  		if (i_size_read(inode) > attr->ia_size)
  			status = ocfs2_truncate_file(inode, bh, attr->ia_size);
  		else

  			status = ocfs2_extend_file(inode, bh, attr->ia_size, 0);

  		if (status < 0) {
  			if (status != -ENOSPC)
  				mlog_errno(status);
  			status = -ENOSPC;
  			goto bail_unlock;
  		}
  	}

  	handle = ocfs2_start_trans(osb, OCFS2_INODE_UPDATE_CREDITS);

  	if (IS_ERR(handle)) {
  		status = PTR_ERR(handle);
  		mlog_errno(status);
  		goto bail_unlock;
  	}

  	/*
  	 * This will intentionally not wind up calling vmtruncate(),
  	 * since all the work for a size change has been done above.
  	 * Otherwise, we could get into problems with truncate as
  	 * ip_alloc_sem is used there to protect against i_size
  	 * changes.
  	 */

  	status = inode_setattr(inode, attr);
  	if (status < 0) {
  		mlog_errno(status);
  		goto bail_commit;
  	}
  
  	status = ocfs2_mark_inode_dirty(handle, inode, bh);
  	if (status < 0)
  		mlog_errno(status);
  
  bail_commit:

  	ocfs2_commit_trans(osb, handle);

  bail_unlock:
  	ocfs2_meta_unlock(inode, 1);
  bail_unlock_rw:
  	if (size_change)
  		ocfs2_rw_unlock(inode, 1);
  bail:
  	if (bh)
  		brelse(bh);
  
  	mlog_exit(status);
  	return status;
  }
  
  int ocfs2_getattr(struct vfsmount *mnt,
  		  struct dentry *dentry,
  		  struct kstat *stat)
  {
  	struct inode *inode = dentry->d_inode;
  	struct super_block *sb = dentry->d_inode->i_sb;
  	struct ocfs2_super *osb = sb->s_fs_info;
  	int err;
  
  	mlog_entry_void();
  
  	err = ocfs2_inode_revalidate(dentry);
  	if (err) {
  		if (err != -ENOENT)
  			mlog_errno(err);
  		goto bail;
  	}
  
  	generic_fillattr(inode, stat);
  
  	/* We set the blksize from the cluster size for performance */
  	stat->blksize = osb->s_clustersize;
  
  bail:
  	mlog_exit(err);
  
  	return err;
  }

  int ocfs2_permission(struct inode *inode, int mask, struct nameidata *nd)
  {
  	int ret;
  
  	mlog_entry_void();
  
  	ret = ocfs2_meta_lock(inode, NULL, 0);
  	if (ret) {

  		if (ret != -ENOENT)
  			mlog_errno(ret);

  		goto out;
  	}
  
  	ret = generic_permission(inode, mask, NULL);

  
  	ocfs2_meta_unlock(inode, 0);
  out:
  	mlog_exit(ret);
  	return ret;
  }

  static int __ocfs2_write_remove_suid(struct inode *inode,
  				     struct buffer_head *bh)

  {
  	int ret;

  	handle_t *handle;

  	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
  	struct ocfs2_dinode *di;

  	mlog_entry("(Inode %llu, mode 0%o)
  ",

  		   (unsigned long long)OCFS2_I(inode)->ip_blkno, inode->i_mode);

  	handle = ocfs2_start_trans(osb, OCFS2_INODE_UPDATE_CREDITS);

  	if (handle == NULL) {
  		ret = -ENOMEM;
  		mlog_errno(ret);
  		goto out;
  	}

  	ret = ocfs2_journal_access(handle, inode, bh,
  				   OCFS2_JOURNAL_ACCESS_WRITE);
  	if (ret < 0) {
  		mlog_errno(ret);

  		goto out_trans;

  	}
  
  	inode->i_mode &= ~S_ISUID;
  	if ((inode->i_mode & S_ISGID) && (inode->i_mode & S_IXGRP))
  		inode->i_mode &= ~S_ISGID;
  
  	di = (struct ocfs2_dinode *) bh->b_data;
  	di->i_mode = cpu_to_le16(inode->i_mode);
  
  	ret = ocfs2_journal_dirty(handle, bh);
  	if (ret < 0)
  		mlog_errno(ret);

  out_trans:

  	ocfs2_commit_trans(osb, handle);

  out:
  	mlog_exit(ret);
  	return ret;
  }

  /*
   * Will look for holes and unwritten extents in the range starting at
   * pos for count bytes (inclusive).
   */
  static int ocfs2_check_range_for_holes(struct inode *inode, loff_t pos,
  				       size_t count)
  {
  	int ret = 0;

  	unsigned int extent_flags;

  	u32 cpos, clusters, extent_len, phys_cpos;
  	struct super_block *sb = inode->i_sb;
  
  	cpos = pos >> OCFS2_SB(sb)->s_clustersize_bits;
  	clusters = ocfs2_clusters_for_bytes(sb, pos + count) - cpos;
  
  	while (clusters) {

  		ret = ocfs2_get_clusters(inode, cpos, &phys_cpos, &extent_len,
  					 &extent_flags);

  		if (ret < 0) {
  			mlog_errno(ret);
  			goto out;
  		}

  		if (phys_cpos == 0 || (extent_flags & OCFS2_EXT_UNWRITTEN)) {

  			ret = 1;
  			break;
  		}
  
  		if (extent_len > clusters)
  			extent_len = clusters;
  
  		clusters -= extent_len;
  		cpos += extent_len;
  	}
  out:
  	return ret;
  }

  static int ocfs2_write_remove_suid(struct inode *inode)
  {
  	int ret;
  	struct buffer_head *bh = NULL;
  	struct ocfs2_inode_info *oi = OCFS2_I(inode);
  
  	ret = ocfs2_read_block(OCFS2_SB(inode->i_sb),
  			       oi->ip_blkno, &bh, OCFS2_BH_CACHED, inode);
  	if (ret < 0) {
  		mlog_errno(ret);
  		goto out;
  	}
  
  	ret =  __ocfs2_write_remove_suid(inode, bh);
  out:
  	brelse(bh);
  	return ret;
  }

  /*
   * Allocate enough extents to cover the region starting at byte offset
   * start for len bytes. Existing extents are skipped, any extents
   * added are marked as "unwritten".
   */
  static int ocfs2_allocate_unwritten_extents(struct inode *inode,
  					    u64 start, u64 len)
  {
  	int ret;
  	u32 cpos, phys_cpos, clusters, alloc_size;
  
  	/*
  	 * We consider both start and len to be inclusive.
  	 */
  	cpos = start >> OCFS2_SB(inode->i_sb)->s_clustersize_bits;
  	clusters = ocfs2_clusters_for_bytes(inode->i_sb, start + len);
  	clusters -= cpos;
  
  	while (clusters) {
  		ret = ocfs2_get_clusters(inode, cpos, &phys_cpos,
  					 &alloc_size, NULL);
  		if (ret) {
  			mlog_errno(ret);
  			goto out;
  		}
  
  		/*
  		 * Hole or existing extent len can be arbitrary, so
  		 * cap it to our own allocation request.
  		 */
  		if (alloc_size > clusters)
  			alloc_size = clusters;
  
  		if (phys_cpos) {
  			/*
  			 * We already have an allocation at this
  			 * region so we can safely skip it.
  			 */
  			goto next;
  		}
  
  		ret = __ocfs2_extend_allocation(inode, cpos, alloc_size, 1);
  		if (ret) {
  			if (ret != -ENOSPC)
  				mlog_errno(ret);
  			goto out;
  		}
  
  next:
  		cpos += alloc_size;
  		clusters -= alloc_size;
  	}
  
  	ret = 0;
  out:
  	return ret;
  }

  static int __ocfs2_remove_inode_range(struct inode *inode,
  				      struct buffer_head *di_bh,
  				      u32 cpos, u32 phys_cpos, u32 len,
  				      struct ocfs2_cached_dealloc_ctxt *dealloc)
  {
  	int ret;
  	u64 phys_blkno = ocfs2_clusters_to_blocks(inode->i_sb, phys_cpos);
  	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
  	struct inode *tl_inode = osb->osb_tl_inode;
  	handle_t *handle;
  	struct ocfs2_alloc_context *meta_ac = NULL;
  	struct ocfs2_dinode *di = (struct ocfs2_dinode *)di_bh->b_data;
  
  	ret = ocfs2_lock_allocators(inode, di, 0, 1, NULL, &meta_ac);
  	if (ret) {
  		mlog_errno(ret);
  		return ret;
  	}
  
  	mutex_lock(&tl_inode->i_mutex);
  
  	if (ocfs2_truncate_log_needs_flush(osb)) {
  		ret = __ocfs2_flush_truncate_log(osb);
  		if (ret < 0) {
  			mlog_errno(ret);
  			goto out;
  		}
  	}
  
  	handle = ocfs2_start_trans(osb, OCFS2_REMOVE_EXTENT_CREDITS);
  	if (handle == NULL) {
  		ret = -ENOMEM;
  		mlog_errno(ret);
  		goto out;
  	}
  
  	ret = ocfs2_journal_access(handle, inode, di_bh,
  				   OCFS2_JOURNAL_ACCESS_WRITE);
  	if (ret) {
  		mlog_errno(ret);
  		goto out;
  	}
  
  	ret = ocfs2_remove_extent(inode, di_bh, cpos, len, handle, meta_ac,
  				  dealloc);
  	if (ret) {
  		mlog_errno(ret);
  		goto out_commit;
  	}
  
  	OCFS2_I(inode)->ip_clusters -= len;
  	di->i_clusters = cpu_to_le32(OCFS2_I(inode)->ip_clusters);
  
  	ret = ocfs2_journal_dirty(handle, di_bh);
  	if (ret) {
  		mlog_errno(ret);
  		goto out_commit;
  	}
  
  	ret = ocfs2_truncate_log_append(osb, handle, phys_blkno, len);
  	if (ret)
  		mlog_errno(ret);
  
  out_commit:
  	ocfs2_commit_trans(osb, handle);
  out:
  	mutex_unlock(&tl_inode->i_mutex);
  
  	if (meta_ac)
  		ocfs2_free_alloc_context(meta_ac);
  
  	return ret;
  }
  
  /*
   * Truncate a byte range, avoiding pages within partial clusters. This
   * preserves those pages for the zeroing code to write to.
   */
  static void ocfs2_truncate_cluster_pages(struct inode *inode, u64 byte_start,
  					 u64 byte_len)
  {
  	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
  	loff_t start, end;
  	struct address_space *mapping = inode->i_mapping;
  
  	start = (loff_t)ocfs2_align_bytes_to_clusters(inode->i_sb, byte_start);
  	end = byte_start + byte_len;
  	end = end & ~(osb->s_clustersize - 1);
  
  	if (start < end) {
  		unmap_mapping_range(mapping, start, end - start, 0);
  		truncate_inode_pages_range(mapping, start, end - 1);
  	}
  }
  
  static int ocfs2_zero_partial_clusters(struct inode *inode,
  				       u64 start, u64 len)
  {
  	int ret = 0;
  	u64 tmpend, end = start + len;
  	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
  	unsigned int csize = osb->s_clustersize;
  	handle_t *handle;
  
  	/*
  	 * The "start" and "end" values are NOT necessarily part of
  	 * the range whose allocation is being deleted. Rather, this
  	 * is what the user passed in with the request. We must zero
  	 * partial clusters here. There's no need to worry about
  	 * physical allocation - the zeroing code knows to skip holes.
  	 */
  	mlog(0, "byte start: %llu, end: %llu
  ",
  	     (unsigned long long)start, (unsigned long long)end);
  
  	/*
  	 * If both edges are on a cluster boundary then there's no
  	 * zeroing required as the region is part of the allocation to
  	 * be truncated.
  	 */
  	if ((start & (csize - 1)) == 0 && (end & (csize - 1)) == 0)
  		goto out;
  
  	handle = ocfs2_start_trans(osb, OCFS2_INODE_UPDATE_CREDITS);
  	if (handle == NULL) {
  		ret = -ENOMEM;
  		mlog_errno(ret);
  		goto out;
  	}
  
  	/*
  	 * We want to get the byte offset of the end of the 1st cluster.
  	 */
  	tmpend = (u64)osb->s_clustersize + (start & ~(osb->s_clustersize - 1));
  	if (tmpend > end)
  		tmpend = end;
  
  	mlog(0, "1st range: start: %llu, tmpend: %llu
  ",
  	     (unsigned long long)start, (unsigned long long)tmpend);
  
  	ret = ocfs2_zero_range_for_truncate(inode, handle, start, tmpend);
  	if (ret)
  		mlog_errno(ret);
  
  	if (tmpend < end) {
  		/*
  		 * This may make start and end equal, but the zeroing
  		 * code will skip any work in that case so there's no
  		 * need to catch it up here.
  		 */
  		start = end & ~(osb->s_clustersize - 1);
  
  		mlog(0, "2nd range: start: %llu, end: %llu
  ",
  		     (unsigned long long)start, (unsigned long long)end);
  
  		ret = ocfs2_zero_range_for_truncate(inode, handle, start, end);
  		if (ret)
  			mlog_errno(ret);
  	}
  
  	ocfs2_commit_trans(osb, handle);
  out:
  	return ret;
  }
  
  static int ocfs2_remove_inode_range(struct inode *inode,
  				    struct buffer_head *di_bh, u64 byte_start,
  				    u64 byte_len)
  {
  	int ret = 0;
  	u32 trunc_start, trunc_len, cpos, phys_cpos, alloc_size;
  	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
  	struct ocfs2_cached_dealloc_ctxt dealloc;
  
  	ocfs2_init_dealloc_ctxt(&dealloc);
  
  	if (byte_len == 0)
  		return 0;
  
  	trunc_start = ocfs2_clusters_for_bytes(osb->sb, byte_start);
  	trunc_len = (byte_start + byte_len) >> osb->s_clustersize_bits;
  	if (trunc_len >= trunc_start)
  		trunc_len -= trunc_start;
  	else
  		trunc_len = 0;
  
  	mlog(0, "Inode: %llu, start: %llu, len: %llu, cstart: %u, clen: %u
  ",
  	     (unsigned long long)OCFS2_I(inode)->ip_blkno,
  	     (unsigned long long)byte_start,
  	     (unsigned long long)byte_len, trunc_start, trunc_len);
  
  	ret = ocfs2_zero_partial_clusters(inode, byte_start, byte_len);
  	if (ret) {
  		mlog_errno(ret);
  		goto out;
  	}
  
  	cpos = trunc_start;
  	while (trunc_len) {
  		ret = ocfs2_get_clusters(inode, cpos, &phys_cpos,
  					 &alloc_size, NULL);
  		if (ret) {
  			mlog_errno(ret);
  			goto out;
  		}
  
  		if (alloc_size > trunc_len)
  			alloc_size = trunc_len;
  
  		/* Only do work for non-holes */
  		if (phys_cpos != 0) {
  			ret = __ocfs2_remove_inode_range(inode, di_bh, cpos,
  							 phys_cpos, alloc_size,
  							 &dealloc);
  			if (ret) {
  				mlog_errno(ret);
  				goto out;
  			}
  		}
  
  		cpos += alloc_size;
  		trunc_len -= alloc_size;
  	}
  
  	ocfs2_truncate_cluster_pages(inode, byte_start, byte_len);
  
  out:
  	ocfs2_schedule_truncate_log_flush(osb, 1);
  	ocfs2_run_deallocs(osb, &dealloc);
  
  	return ret;
  }

  /*
   * Parts of this function taken from xfs_change_file_space()
   */

  static int __ocfs2_change_file_space(struct file *file, struct inode *inode,
  				     loff_t f_pos, unsigned int cmd,
  				     struct ocfs2_space_resv *sr,
  				     int change_size)

  {
  	int ret;
  	s64 llen;

  	loff_t size;

  	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
  	struct buffer_head *di_bh = NULL;
  	handle_t *handle;
  	unsigned long long max_off = ocfs2_max_file_offset(inode->i_sb->s_blocksize_bits);

  	if (ocfs2_is_hard_readonly(osb) || ocfs2_is_soft_readonly(osb))
  		return -EROFS;
  
  	mutex_lock(&inode->i_mutex);
  
  	/*
  	 * This prevents concurrent writes on other nodes
  	 */
  	ret = ocfs2_rw_lock(inode, 1);
  	if (ret) {
  		mlog_errno(ret);
  		goto out;
  	}
  
  	ret = ocfs2_meta_lock(inode, &di_bh, 1);
  	if (ret) {
  		mlog_errno(ret);
  		goto out_rw_unlock;
  	}
  
  	if (inode->i_flags & (S_IMMUTABLE|S_APPEND)) {
  		ret = -EPERM;
  		goto out_meta_unlock;
  	}
  
  	switch (sr->l_whence) {
  	case 0: /*SEEK_SET*/
  		break;
  	case 1: /*SEEK_CUR*/

  		sr->l_start += f_pos;

  		break;
  	case 2: /*SEEK_END*/
  		sr->l_start += i_size_read(inode);
  		break;
  	default:
  		ret = -EINVAL;
  		goto out_meta_unlock;
  	}
  	sr->l_whence = 0;
  
  	llen = sr->l_len > 0 ? sr->l_len - 1 : sr->l_len;
  
  	if (sr->l_start < 0
  	    || sr->l_start > max_off
  	    || (sr->l_start + llen) < 0
  	    || (sr->l_start + llen) > max_off) {
  		ret = -EINVAL;
  		goto out_meta_unlock;
  	}

  	size = sr->l_start + sr->l_len;

  
  	if (cmd == OCFS2_IOC_RESVSP || cmd == OCFS2_IOC_RESVSP64) {
  		if (sr->l_len <= 0) {
  			ret = -EINVAL;
  			goto out_meta_unlock;
  		}
  	}

  	if (file && should_remove_suid(file->f_path.dentry)) {

  		ret = __ocfs2_write_remove_suid(inode, di_bh);
  		if (ret) {
  			mlog_errno(ret);
  			goto out_meta_unlock;
  		}
  	}
  
  	down_write(&OCFS2_I(inode)->ip_alloc_sem);
  	switch (cmd) {
  	case OCFS2_IOC_RESVSP:
  	case OCFS2_IOC_RESVSP64:
  		/*
  		 * This takes unsigned offsets, but the signed ones we
  		 * pass have been checked against overflow above.
  		 */
  		ret = ocfs2_allocate_unwritten_extents(inode, sr->l_start,
  						       sr->l_len);
  		break;
  	case OCFS2_IOC_UNRESVSP:
  	case OCFS2_IOC_UNRESVSP64:
  		ret = ocfs2_remove_inode_range(inode, di_bh, sr->l_start,
  					       sr->l_len);
  		break;
  	default:
  		ret = -EINVAL;
  	}
  	up_write(&OCFS2_I(inode)->ip_alloc_sem);
  	if (ret) {
  		mlog_errno(ret);
  		goto out_meta_unlock;
  	}
  
  	/*
  	 * We update c/mtime for these changes
  	 */
  	handle = ocfs2_start_trans(osb, OCFS2_INODE_UPDATE_CREDITS);
  	if (IS_ERR(handle)) {
  		ret = PTR_ERR(handle);
  		mlog_errno(ret);
  		goto out_meta_unlock;
  	}

  	if (change_size && i_size_read(inode) < size)
  		i_size_write(inode, size);

  	inode->i_ctime = inode->i_mtime = CURRENT_TIME;
  	ret = ocfs2_mark_inode_dirty(handle, inode, di_bh);
  	if (ret < 0)
  		mlog_errno(ret);
  
  	ocfs2_commit_trans(osb, handle);
  
  out_meta_unlock:
  	brelse(di_bh);
  	ocfs2_meta_unlock(inode, 1);
  out_rw_unlock:
  	ocfs2_rw_unlock(inode, 1);
  
  	mutex_unlock(&inode->i_mutex);
  out:
  	return ret;
  }

  int ocfs2_change_file_space(struct file *file, unsigned int cmd,
  			    struct ocfs2_space_resv *sr)
  {
  	struct inode *inode = file->f_path.dentry->d_inode;
  	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);;
  
  	if ((cmd == OCFS2_IOC_RESVSP || cmd == OCFS2_IOC_RESVSP64) &&
  	    !ocfs2_writes_unwritten_extents(osb))
  		return -ENOTTY;
  	else if ((cmd == OCFS2_IOC_UNRESVSP || cmd == OCFS2_IOC_UNRESVSP64) &&
  		 !ocfs2_sparse_alloc(osb))
  		return -ENOTTY;
  
  	if (!S_ISREG(inode->i_mode))
  		return -EINVAL;
  
  	if (!(file->f_mode & FMODE_WRITE))
  		return -EBADF;
  
  	return __ocfs2_change_file_space(file, inode, file->f_pos, cmd, sr, 0);
  }
  
  static long ocfs2_fallocate(struct inode *inode, int mode, loff_t offset,
  			    loff_t len)
  {
  	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
  	struct ocfs2_space_resv sr;
  	int change_size = 1;
  
  	if (!ocfs2_writes_unwritten_extents(osb))
  		return -EOPNOTSUPP;
  
  	if (S_ISDIR(inode->i_mode))
  		return -ENODEV;
  
  	if (mode & FALLOC_FL_KEEP_SIZE)
  		change_size = 0;
  
  	sr.l_whence = 0;
  	sr.l_start = (s64)offset;
  	sr.l_len = (s64)len;
  
  	return __ocfs2_change_file_space(NULL, inode, offset,
  					 OCFS2_IOC_RESVSP64, &sr, change_size);
  }

  static int ocfs2_prepare_inode_for_write(struct dentry *dentry,
  					 loff_t *ppos,
  					 size_t count,

  					 int appending,
  					 int *direct_io)

  {

  	int ret = 0, meta_level = appending;
  	struct inode *inode = dentry->d_inode;

  	u32 clusters;

  	loff_t newsize, saved_pos;

  	/* 
  	 * We sample i_size under a read level meta lock to see if our write
  	 * is extending the file, if it is we back off and get a write level
  	 * meta lock.
  	 */

  	for(;;) {

  		ret = ocfs2_meta_lock(inode, NULL, meta_level);

  		if (ret < 0) {
  			meta_level = -1;
  			mlog_errno(ret);
  			goto out;
  		}
  
  		/* Clear suid / sgid if necessary. We do this here
  		 * instead of later in the write path because
  		 * remove_suid() calls ->setattr without any hint that
  		 * we may have already done our cluster locking. Since
  		 * ocfs2_setattr() *must* take cluster locks to
  		 * proceeed, this will lead us to recursively lock the
  		 * inode. There's also the dinode i_size state which
  		 * can be lost via setattr during extending writes (we
  		 * set inode->i_size at the end of a write. */

  		if (should_remove_suid(dentry)) {

  			if (meta_level == 0) {
  				ocfs2_meta_unlock(inode, meta_level);
  				meta_level = 1;
  				continue;
  			}
  
  			ret = ocfs2_write_remove_suid(inode);
  			if (ret < 0) {
  				mlog_errno(ret);

  				goto out_unlock;

  			}
  		}
  
  		/* work on a copy of ppos until we're sure that we won't have
  		 * to recalculate it due to relocking. */

  		if (appending) {

  			saved_pos = i_size_read(inode);
  			mlog(0, "O_APPEND: inode->i_size=%llu
  ", saved_pos);
  		} else {

  			saved_pos = *ppos;

  		}

  		if (ocfs2_sparse_alloc(OCFS2_SB(inode->i_sb))) {
  			loff_t end = saved_pos + count;
  
  			/*
  			 * Skip the O_DIRECT checks if we don't need
  			 * them.
  			 */
  			if (!direct_io || !(*direct_io))
  				break;
  
  			/*
  			 * Allowing concurrent direct writes means
  			 * i_size changes wouldn't be synchronized, so
  			 * one node could wind up truncating another
  			 * nodes writes.
  			 */
  			if (end > i_size_read(inode)) {
  				*direct_io = 0;
  				break;
  			}
  
  			/*
  			 * We don't fill holes during direct io, so
  			 * check for them here. If any are found, the
  			 * caller will have to retake some cluster
  			 * locks and initiate the io as buffered.
  			 */
  			ret = ocfs2_check_range_for_holes(inode, saved_pos,
  							  count);
  			if (ret == 1) {
  				*direct_io = 0;
  				ret = 0;
  			} else if (ret < 0)
  				mlog_errno(ret);
  			break;
  		}

  		/*
  		 * The rest of this loop is concerned with legacy file
  		 * systems which don't support sparse files.
  		 */

  		newsize = count + saved_pos;

  		mlog(0, "pos=%lld newsize=%lld cursize=%lld
  ",
  		     (long long) saved_pos, (long long) newsize,
  		     (long long) i_size_read(inode));

  
  		/* No need for a higher level metadata lock if we're
  		 * never going past i_size. */
  		if (newsize <= i_size_read(inode))
  			break;
  
  		if (meta_level == 0) {
  			ocfs2_meta_unlock(inode, meta_level);
  			meta_level = 1;
  			continue;
  		}
  
  		spin_lock(&OCFS2_I(inode)->ip_lock);
  		clusters = ocfs2_clusters_for_bytes(inode->i_sb, newsize) -
  			OCFS2_I(inode)->ip_clusters;
  		spin_unlock(&OCFS2_I(inode)->ip_lock);
  
  		mlog(0, "Writing at EOF, may need more allocation: "

  		     "i_size = %lld, newsize = %lld, need %u clusters
  ",
  		     (long long) i_size_read(inode), (long long) newsize,
  		     clusters);

  
  		/* We only want to continue the rest of this loop if
  		 * our extend will actually require more
  		 * allocation. */
  		if (!clusters)
  			break;

  		ret = ocfs2_extend_file(inode, NULL, newsize, count);

  		if (ret < 0) {
  			if (ret != -ENOSPC)
  				mlog_errno(ret);

  			goto out_unlock;

  		}

  		break;
  	}

  	if (appending)
  		*ppos = saved_pos;
  
  out_unlock:

  	ocfs2_meta_unlock(inode, meta_level);

  
  out:
  	return ret;
  }

  static inline void
  ocfs2_set_next_iovec(const struct iovec **iovp, size_t *basep, size_t bytes)
  {
  	const struct iovec *iov = *iovp;
  	size_t base = *basep;
  
  	do {
  		int copy = min(bytes, iov->iov_len - base);
  
  		bytes -= copy;
  		base += copy;
  		if (iov->iov_len == base) {
  			iov++;
  			base = 0;
  		}
  	} while (bytes);
  	*iovp = iov;
  	*basep = base;
  }

  static struct page * ocfs2_get_write_source(char **ret_src_buf,

  					    const struct iovec *cur_iov,
  					    size_t iov_offset)
  {
  	int ret;

  	char *buf = cur_iov->iov_base + iov_offset;

  	struct page *src_page = NULL;

  	unsigned long off;

  	off = (unsigned long)(buf) & ~PAGE_CACHE_MASK;

  
  	if (!segment_eq(get_fs(), KERNEL_DS)) {
  		/*
  		 * Pull in the user page. We want to do this outside
  		 * of the meta data locks in order to preserve locking
  		 * order in case of page fault.
  		 */
  		ret = get_user_pages(current, current->mm,
  				     (unsigned long)buf & PAGE_CACHE_MASK, 1,
  				     0, 0, &src_page, NULL);
  		if (ret == 1)

  			*ret_src_buf = kmap(src_page) + off;

  		else
  			src_page = ERR_PTR(-EFAULT);
  	} else {

  		*ret_src_buf = buf;

  	}
  
  	return src_page;
  }

  static void ocfs2_put_write_source(struct page *page)

  {
  	if (page) {
  		kunmap(page);
  		page_cache_release(page);
  	}
  }
  
  static ssize_t ocfs2_file_buffered_write(struct file *file, loff_t *ppos,
  					 const struct iovec *iov,
  					 unsigned long nr_segs,
  					 size_t count,
  					 ssize_t o_direct_written)
  {
  	int ret = 0;
  	ssize_t copied, total = 0;

  	size_t iov_offset = 0, bytes;
  	loff_t pos;

  	const struct iovec *cur_iov = iov;

  	struct page *user_page, *page;

  	char * uninitialized_var(buf);
  	char *dst;

  	void *fsdata;

  
  	/*
  	 * handle partial DIO write.  Adjust cur_iov if needed.
  	 */
  	ocfs2_set_next_iovec(&cur_iov, &iov_offset, o_direct_written);
  
  	do {

  		pos = *ppos;

  		user_page = ocfs2_get_write_source(&buf, cur_iov, iov_offset);
  		if (IS_ERR(user_page)) {
  			ret = PTR_ERR(user_page);

  			goto out;
  		}

  		/* Stay within our page boundaries */
  		bytes = min((PAGE_CACHE_SIZE - ((unsigned long)pos & ~PAGE_CACHE_MASK)),
  			    (PAGE_CACHE_SIZE - ((unsigned long)buf & ~PAGE_CACHE_MASK)));
  		/* Stay within the vector boundary */
  		bytes = min_t(size_t, bytes, cur_iov->iov_len - iov_offset);
  		/* Stay within count */
  		bytes = min(bytes, count);
  
  		page = NULL;
  		ret = ocfs2_write_begin(file, file->f_mapping, pos, bytes, 0,
  					&page, &fsdata);
  		if (ret) {
  			mlog_errno(ret);
  			goto out;
  		}

  		dst = kmap_atomic(page, KM_USER0);
  		memcpy(dst + (pos & (PAGE_CACHE_SIZE - 1)), buf, bytes);
  		kunmap_atomic(dst, KM_USER0);
  		flush_dcache_page(page);
  		ocfs2_put_write_source(user_page);

  		copied = ocfs2_write_end(file, file->f_mapping, pos, bytes,
  					 bytes, page, fsdata);

  		if (copied < 0) {
  			mlog_errno(copied);
  			ret = copied;
  			goto out;
  		}
  
  		total += copied;

  		*ppos = pos + copied;

  		count -= copied;
  
  		ocfs2_set_next_iovec(&cur_iov, &iov_offset, copied);
  	} while(count);
  
  out:
  	return total ? total : ret;
  }

  static ssize_t ocfs2_file_aio_write(struct kiocb *iocb,
  				    const struct iovec *iov,
  				    unsigned long nr_segs,
  				    loff_t pos)
  {

  	int ret, direct_io, appending, rw_level, have_alloc_sem  = 0;
  	int can_do_direct, sync = 0;
  	ssize_t written = 0;
  	size_t ocount;		/* original count */
  	size_t count;		/* after file limit checks */
  	loff_t *ppos = &iocb->ki_pos;
  	struct file *file = iocb->ki_filp;
  	struct inode *inode = file->f_path.dentry->d_inode;
  
  	mlog_entry("(0x%p, %u, '%.*s')
  ", file,

  		   (unsigned int)nr_segs,

  		   file->f_path.dentry->d_name.len,
  		   file->f_path.dentry->d_name.name);

  	if (iocb->ki_left == 0)
  		return 0;

  	ret = generic_segment_checks(iov, &nr_segs, &ocount, VERIFY_READ);

  	if (ret)
  		return ret;
  
  	count = ocount;
  
  	vfs_check_frozen(inode->i_sb, SB_FREEZE_WRITE);
  
  	appending = file->f_flags & O_APPEND ? 1 : 0;
  	direct_io = file->f_flags & O_DIRECT ? 1 : 0;

  	mutex_lock(&inode->i_mutex);

  
  relock:

  	/* to match setattr's i_mutex -> i_alloc_sem -> rw_lock ordering */

  	if (direct_io) {

  		down_read(&inode->i_alloc_sem);

  		have_alloc_sem = 1;

  	}
  
  	/* concurrent O_DIRECT writes are allowed */

  	rw_level = !direct_io;

  	ret = ocfs2_rw_lock(inode, rw_level);
  	if (ret < 0) {

  		mlog_errno(ret);

  		goto out_sems;

  	}

  	can_do_direct = direct_io;
  	ret = ocfs2_prepare_inode_for_write(file->f_path.dentry, ppos,
  					    iocb->ki_left, appending,
  					    &can_do_direct);

  	if (ret < 0) {
  		mlog_errno(ret);
  		goto out;
  	}

  	/*
  	 * We can't complete the direct I/O as requested, fall back to
  	 * buffered I/O.
  	 */
  	if (direct_io && !can_do_direct) {
  		ocfs2_rw_unlock(inode, rw_level);
  		up_read(&inode->i_alloc_sem);
  
  		have_alloc_sem = 0;
  		rw_level = -1;
  
  		direct_io = 0;
  		sync = 1;
  		goto relock;
  	}
  
  	if (!sync && ((file->f_flags & O_SYNC) || IS_SYNC(inode)))
  		sync = 1;
  
  	/*
  	 * XXX: Is it ok to execute these checks a second time?
  	 */
  	ret = generic_write_checks(file, ppos, &count, S_ISBLK(inode->i_mode));
  	if (ret)
  		goto out;
  
  	/*
  	 * Set pos so that sync_page_range_nolock() below understands
  	 * where to start from. We might've moved it around via the
  	 * calls above. The range we want to actually sync starts from
  	 * *ppos here.
  	 *
  	 */
  	pos = *ppos;

  	/* communicate with ocfs2_dio_end_io */

  	ocfs2_iocb_set_rw_locked(iocb, rw_level);

  	if (direct_io) {
  		written = generic_file_direct_write(iocb, iov, &nr_segs, *ppos,
  						    ppos, count, ocount);
  		if (written < 0) {
  			ret = written;
  			goto out_dio;
  		}
  	} else {
  		written = ocfs2_file_buffered_write(file, ppos, iov, nr_segs,
  						    count, written);
  		if (written < 0) {
  			ret = written;
  			if (ret != -EFAULT || ret != -ENOSPC)
  				mlog_errno(ret);
  			goto out;
  		}
  	}

  out_dio:

  	/* buffered aio wouldn't have proper lock coverage today */

  	BUG_ON(ret == -EIOCBQUEUED && !(file->f_flags & O_DIRECT));

  
  	/* 
  	 * deep in g_f_a_w_n()->ocfs2_direct_IO we pass in a ocfs2_dio_end_io
  	 * function pointer which is called when o_direct io completes so that
  	 * it can unlock our rw lock.  (it's the clustered equivalent of
  	 * i_alloc_sem; protects truncate from racing with pending ios).
  	 * Unfortunately there are error cases which call end_io and others
  	 * that don't.  so we don't have to unlock the rw_lock if either an
  	 * async dio is going to do it in the future or an end_io after an
  	 * error has already done it.
  	 */
  	if (ret == -EIOCBQUEUED || !ocfs2_iocb_is_rw_locked(iocb)) {
  		rw_level = -1;
  		have_alloc_sem = 0;
  	}
  
  out:

  	if (rw_level != -1)
  		ocfs2_rw_unlock(inode, rw_level);
  
  out_sems:

  	if (have_alloc_sem)
  		up_read(&inode->i_alloc_sem);

  
  	if (written > 0 && sync) {
  		ssize_t err;
  
  		err = sync_page_range_nolock(inode, file->f_mapping, pos, count);
  		if (err < 0)
  			written = err;
  	}

  	mutex_unlock(&inode->i_mutex);

  
  	mlog_exit(ret);

  	return written ? written : ret;

  }

  static int ocfs2_splice_write_actor(struct pipe_inode_info *pipe,
  				    struct pipe_buffer *buf,
  				    struct splice_desc *sd)
  {

  	int ret, count;

  	ssize_t copied = 0;

  	struct file *file = sd->u.file;
  	unsigned int offset;
  	struct page *page = NULL;
  	void *fsdata;
  	char *src, *dst;

  	ret = buf->ops->confirm(pipe, buf);

  	if (ret)
  		goto out;

  	offset = sd->pos & ~PAGE_CACHE_MASK;

  	count = sd->len;

  	if (count + offset > PAGE_CACHE_SIZE)
  		count = PAGE_CACHE_SIZE - offset;

  	ret = ocfs2_write_begin(file, file->f_mapping, sd->pos, count, 0,
  				&page, &fsdata);
  	if (ret) {
  		mlog_errno(ret);
  		goto out;
  	}

  	src = buf->ops->map(pipe, buf, 1);
  	dst = kmap_atomic(page, KM_USER1);
  	memcpy(dst + offset, src + buf->offset, count);
  	kunmap_atomic(page, KM_USER1);
  	buf->ops->unmap(pipe, buf, src);

  	copied = ocfs2_write_end(file, file->f_mapping, sd->pos, count, count,
  				 page, fsdata);
  	if (copied < 0) {
  		mlog_errno(copied);
  		ret = copied;
  		goto out;
  	}

  out:

  	return copied ? copied : ret;

  }
  
  static ssize_t __ocfs2_file_splice_write(struct pipe_inode_info *pipe,
  					 struct file *out,
  					 loff_t *ppos,
  					 size_t len,
  					 unsigned int flags)
  {
  	int ret, err;
  	struct address_space *mapping = out->f_mapping;
  	struct inode *inode = mapping->host;

  	struct splice_desc sd = {
  		.total_len = len,
  		.flags = flags,
  		.pos = *ppos,

  		.u.file = out,

  	};
  
  	ret = __splice_from_pipe(pipe, &sd, ocfs2_splice_write_actor);

  	if (ret > 0) {
  		*ppos += ret;
  
  		if (unlikely((out->f_flags & O_SYNC) || IS_SYNC(inode))) {
  			err = generic_osync_inode(inode, mapping,
  						  OSYNC_METADATA|OSYNC_DATA);
  			if (err)
  				ret = err;
  		}
  	}
  
  	return ret;
  }

  static ssize_t ocfs2_file_splice_write(struct pipe_inode_info *pipe,
  				       struct file *out,
  				       loff_t *ppos,
  				       size_t len,
  				       unsigned int flags)
  {
  	int ret;

  	struct inode *inode = out->f_path.dentry->d_inode;

  
  	mlog_entry("(0x%p, 0x%p, %u, '%.*s')
  ", out, pipe,
  		   (unsigned int)len,

  		   out->f_path.dentry->d_name.len,
  		   out->f_path.dentry->d_name.name);

  
  	inode_double_lock(inode, pipe->inode);
  
  	ret = ocfs2_rw_lock(inode, 1);
  	if (ret < 0) {
  		mlog_errno(ret);
  		goto out;
  	}

  	ret = ocfs2_prepare_inode_for_write(out->f_path.dentry, ppos, len, 0,
  					    NULL);

  	if (ret < 0) {
  		mlog_errno(ret);
  		goto out_unlock;
  	}
  
  	/* ok, we're done with i_size and alloc work */

  	ret = __ocfs2_file_splice_write(pipe, out, ppos, len, flags);

  
  out_unlock:
  	ocfs2_rw_unlock(inode, 1);
  out:
  	inode_double_unlock(inode, pipe->inode);
  
  	mlog_exit(ret);
  	return ret;
  }
  
  static ssize_t ocfs2_file_splice_read(struct file *in,
  				      loff_t *ppos,
  				      struct pipe_inode_info *pipe,
  				      size_t len,
  				      unsigned int flags)
  {
  	int ret = 0;

  	struct inode *inode = in->f_path.dentry->d_inode;

  
  	mlog_entry("(0x%p, 0x%p, %u, '%.*s')
  ", in, pipe,
  		   (unsigned int)len,

  		   in->f_path.dentry->d_name.len,
  		   in->f_path.dentry->d_name.name);

  
  	/*
  	 * See the comment in ocfs2_file_aio_read()
  	 */
  	ret = ocfs2_meta_lock(inode, NULL, 0);
  	if (ret < 0) {
  		mlog_errno(ret);
  		goto bail;
  	}
  	ocfs2_meta_unlock(inode, 0);
  
  	ret = generic_file_splice_read(in, ppos, pipe, len, flags);
  
  bail:
  	mlog_exit(ret);
  	return ret;
  }

  static ssize_t ocfs2_file_aio_read(struct kiocb *iocb,

  				   const struct iovec *iov,
  				   unsigned long nr_segs,

  				   loff_t pos)
  {

  	int ret = 0, rw_level = -1, have_alloc_sem = 0, lock_level = 0;

  	struct file *filp = iocb->ki_filp;

  	struct inode *inode = filp->f_path.dentry->d_inode;

  	mlog_entry("(0x%p, %u, '%.*s')
  ", filp,
  		   (unsigned int)nr_segs,

  		   filp->f_path.dentry->d_name.len,
  		   filp->f_path.dentry->d_name.name);

  
  	if (!inode) {
  		ret = -EINVAL;
  		mlog_errno(ret);
  		goto bail;
  	}

  	/* 
  	 * buffered reads protect themselves in ->readpage().  O_DIRECT reads
  	 * need locks to protect pending reads from racing with truncate.
  	 */
  	if (filp->f_flags & O_DIRECT) {
  		down_read(&inode->i_alloc_sem);
  		have_alloc_sem = 1;
  
  		ret = ocfs2_rw_lock(inode, 0);
  		if (ret < 0) {
  			mlog_errno(ret);
  			goto bail;
  		}
  		rw_level = 0;
  		/* communicate with ocfs2_dio_end_io */

  		ocfs2_iocb_set_rw_locked(iocb, rw_level);

  	}

  	/*
  	 * We're fine letting folks race truncates and extending
  	 * writes with read across the cluster, just like they can
  	 * locally. Hence no rw_lock during read.
  	 * 
  	 * Take and drop the meta data lock to update inode fields
  	 * like i_size. This allows the checks down below
  	 * generic_file_aio_read() a chance of actually working. 
  	 */

  	ret = ocfs2_meta_lock_atime(inode, filp->f_vfsmnt, &lock_level);

  	if (ret < 0) {
  		mlog_errno(ret);
  		goto bail;
  	}

  	ocfs2_meta_unlock(inode, lock_level);

  	ret = generic_file_aio_read(iocb, iov, nr_segs, iocb->ki_pos);

  	if (ret == -EINVAL)
  		mlog(ML_ERROR, "generic_file_aio_read returned -EINVAL
  ");
  
  	/* buffered aio wouldn't have proper lock coverage today */
  	BUG_ON(ret == -EIOCBQUEUED && !(filp->f_flags & O_DIRECT));
  
  	/* see ocfs2_file_aio_write */
  	if (ret == -EIOCBQUEUED || !ocfs2_iocb_is_rw_locked(iocb)) {
  		rw_level = -1;
  		have_alloc_sem = 0;
  	}
  
  bail:
  	if (have_alloc_sem)
  		up_read(&inode->i_alloc_sem);
  	if (rw_level != -1) 
  		ocfs2_rw_unlock(inode, rw_level);
  	mlog_exit(ret);
  
  	return ret;
  }

  const struct inode_operations ocfs2_file_iops = {

  	.setattr	= ocfs2_setattr,
  	.getattr	= ocfs2_getattr,

  	.permission	= ocfs2_permission,

  	.fallocate	= ocfs2_fallocate,

  };

  const struct inode_operations ocfs2_special_file_iops = {

  	.setattr	= ocfs2_setattr,
  	.getattr	= ocfs2_getattr,

  	.permission	= ocfs2_permission,

  };

  const struct file_operations ocfs2_fops = {

  	.read		= do_sync_read,
  	.write		= do_sync_write,

  	.mmap		= ocfs2_mmap,
  	.fsync		= ocfs2_sync_file,
  	.release	= ocfs2_file_release,
  	.open		= ocfs2_file_open,
  	.aio_read	= ocfs2_file_aio_read,
  	.aio_write	= ocfs2_file_aio_write,

  	.ioctl		= ocfs2_ioctl,

  #ifdef CONFIG_COMPAT
  	.compat_ioctl   = ocfs2_compat_ioctl,
  #endif

  	.splice_read	= ocfs2_file_splice_read,
  	.splice_write	= ocfs2_file_splice_write,

  };

  const struct file_operations ocfs2_dops = {

  	.read		= generic_read_dir,
  	.readdir	= ocfs2_readdir,
  	.fsync		= ocfs2_sync_file,

  	.ioctl		= ocfs2_ioctl,

  #ifdef CONFIG_COMPAT
  	.compat_ioctl   = ocfs2_compat_ioctl,
  #endif

  };