text: /* -*- 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>
  #include <linux/quotaops.h>
  #include <linux/blkdev.h>
  
  #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 "locks.h"
  #include "mmap.h"
  #include "suballoc.h"
  #include "super.h"
  #include "xattr.h"
  #include "acl.h"
  #include "quota.h"
  #include "refcounttree.h"
  #include "ocfs2_trace.h"
  
  #include "buffer_head_io.h"
  
  static int ocfs2_init_file_private(struct inode *inode, struct file *file)
  {
  	struct ocfs2_file_private *fp;
  
  	fp = kzalloc(sizeof(struct ocfs2_file_private), GFP_KERNEL);
  	if (!fp)
  		return -ENOMEM;
  
  	fp->fp_file = file;
  	mutex_init(&fp->fp_mutex);
  	ocfs2_file_lock_res_init(&fp->fp_flock, fp);
  	file->private_data = fp;
  
  	return 0;
  }
  
  static void ocfs2_free_file_private(struct inode *inode, struct file *file)
  {
  	struct ocfs2_file_private *fp = file->private_data;
  	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
  
  	if (fp) {
  		ocfs2_simple_drop_lockres(osb, &fp->fp_flock);
  		ocfs2_lock_res_free(&fp->fp_flock);
  		kfree(fp);
  		file->private_data = NULL;
  	}
  }
  
  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);
  
  	trace_ocfs2_file_open(inode, file, file->f_path.dentry,
  			      (unsigned long long)OCFS2_I(inode)->ip_blkno,
  			      file->f_path.dentry->d_name.len,
  			      file->f_path.dentry->d_name.name, mode);
  
  	if (file->f_mode & FMODE_WRITE)
  		dquot_initialize(inode);
  
  	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 = ocfs2_init_file_private(inode, file);
  	if (status) {
  		/*
  		 * We want to set open count back if we're failing the
  		 * open.
  		 */
  		spin_lock(&oi->ip_lock);
  		oi->ip_open_count--;
  		spin_unlock(&oi->ip_lock);
  	}
  
  leave:
  	return status;
  }
  
  static int ocfs2_file_release(struct inode *inode, struct file *file)
  {
  	struct ocfs2_inode_info *oi = OCFS2_I(inode);
  
  	spin_lock(&oi->ip_lock);
  	if (!--oi->ip_open_count)
  		oi->ip_flags &= ~OCFS2_INODE_OPEN_DIRECT;
  
  	trace_ocfs2_file_release(inode, file, file->f_path.dentry,
  				 oi->ip_blkno,
  				 file->f_path.dentry->d_name.len,
  				 file->f_path.dentry->d_name.name,
  				 oi->ip_open_count);
  	spin_unlock(&oi->ip_lock);
  
  	ocfs2_free_file_private(inode, file);
  
  	return 0;
  }
  
  static int ocfs2_dir_open(struct inode *inode, struct file *file)
  {
  	return ocfs2_init_file_private(inode, file);
  }
  
  static int ocfs2_dir_release(struct inode *inode, struct file *file)
  {
  	ocfs2_free_file_private(inode, file);
  	return 0;
  }
  
  static int ocfs2_sync_file(struct file *file, loff_t start, loff_t end,
  			   int datasync)
  {
  	int err = 0;
  	journal_t *journal;
  	struct inode *inode = file->f_mapping->host;
  	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
  
  	trace_ocfs2_sync_file(inode, file, file->f_path.dentry,
  			      OCFS2_I(inode)->ip_blkno,
  			      file->f_path.dentry->d_name.len,
  			      file->f_path.dentry->d_name.name,
  			      (unsigned long long)datasync);
  
  	err = filemap_write_and_wait_range(inode->i_mapping, start, end);
  	if (err)
  		return err;
  
  	/*
  	 * Probably don't need the i_mutex at all in here, just putting it here
  	 * to be consistent with how fsync used to be called, someone more
  	 * familiar with the fs could possibly remove it.
  	 */
  	mutex_lock(&inode->i_mutex);
  	if (datasync && !(inode->i_state & I_DIRTY_DATASYNC)) {
  		/*
  		 * We still have to flush drive's caches to get data to the
  		 * platter
  		 */
  		if (osb->s_mount_opt & OCFS2_MOUNT_BARRIER)
  			blkdev_issue_flush(inode->i_sb->s_bdev, GFP_KERNEL, NULL);
  		goto bail;
  	}
  
  	journal = osb->journal->j_journal;
  	err = jbd2_journal_force_commit(journal);
  
  bail:
  	if (err)
  		mlog_errno(err);
  	mutex_unlock(&inode->i_mutex);
  
  	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;
  	struct ocfs2_dinode *di = (struct ocfs2_dinode *) bh->b_data;
  
  	handle = ocfs2_start_trans(osb, OCFS2_INODE_UPDATE_CREDITS);
  	if (IS_ERR(handle)) {
  		ret = PTR_ERR(handle);
  		mlog_errno(ret);
  		goto out;
  	}
  
  	ret = ocfs2_journal_access_di(handle, INODE_CACHE(inode), bh,
  				      OCFS2_JOURNAL_ACCESS_WRITE);
  	if (ret) {
  		mlog_errno(ret);
  		goto out_commit;
  	}
  
  	/*
  	 * Don't use ocfs2_mark_inode_dirty() here as we don't always
  	 * have i_mutex to guard against concurrent changes to other
  	 * inode fields.
  	 */
  	inode->i_atime = CURRENT_TIME;
  	di->i_atime = cpu_to_le64(inode->i_atime.tv_sec);
  	di->i_atime_nsec = cpu_to_le32(inode->i_atime.tv_nsec);
  	ocfs2_journal_dirty(handle, bh);
  
  out_commit:
  	ocfs2_commit_trans(OCFS2_SB(inode->i_sb), handle);
  out:
  	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;
  
  	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:
  	return status;
  }
  
  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 (IS_ERR(handle)) {
  		ret = PTR_ERR(handle);
  		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_cow_file_pos(struct inode *inode,
  			      struct buffer_head *fe_bh,
  			      u64 offset)
  {
  	int status;
  	u32 phys, cpos = offset >> OCFS2_SB(inode->i_sb)->s_clustersize_bits;
  	unsigned int num_clusters = 0;
  	unsigned int ext_flags = 0;
  
  	/*
  	 * If the new offset is aligned to the range of the cluster, there is
  	 * no space for ocfs2_zero_range_for_truncate to fill, so no need to
  	 * CoW either.
  	 */
  	if ((offset & (OCFS2_SB(inode->i_sb)->s_clustersize - 1)) == 0)
  		return 0;
  
  	status = ocfs2_get_clusters(inode, cpos, &phys,
  				    &num_clusters, &ext_flags);
  	if (status) {
  		mlog_errno(status);
  		goto out;
  	}
  
  	if (!(ext_flags & OCFS2_EXT_REFCOUNTED))
  		goto out;
  
  	return ocfs2_refcount_cow(inode, NULL, fe_bh, cpos, 1, cpos+1);
  
  out:
  	return status;
  }
  
  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;
  
  	/*
  	 * We need to CoW the cluster contains the offset if it is reflinked
  	 * since we will call ocfs2_zero_range_for_truncate later which will
  	 * write "0" from offset to the end of the cluster.
  	 */
  	status = ocfs2_cow_file_pos(inode, fe_bh, new_i_size);
  	if (status) {
  		mlog_errno(status);
  		return status;
  	}
  
  	/* 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_di(handle, INODE_CACHE(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_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);
  
  	ocfs2_journal_dirty(handle, fe_bh);
  
  out_commit:
  	ocfs2_commit_trans(osb, handle);
  out:
  	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);
  
  	/* We trust di_bh because it comes from ocfs2_inode_lock(), which
  	 * already validated it */
  	fe = (struct ocfs2_dinode *) di_bh->b_data;
  
  	trace_ocfs2_truncate_file((unsigned long long)OCFS2_I(inode)->ip_blkno,
  				  (unsigned long long)le64_to_cpu(fe->i_size),
  				  (unsigned long long)new_i_size);
  
  	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\n",
  			(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)) {
  		trace_ocfs2_truncate_file_error(
  			(unsigned long long)le64_to_cpu(fe->i_size),
  			(unsigned long long)new_i_size);
  		status = -EINVAL;
  		mlog_errno(status);
  		goto bail;
  	}
  
  	/* 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);
  
  	ocfs2_resv_discard(&osb->osb_la_resmap,
  			   &OCFS2_I(inode)->ip_la_data_resv);
  
  	/*
  	 * The inode lock forced other nodes to sync and drop their
  	 * pages, which (correctly) happens 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.
  	 */
  	unmap_mapping_range(inode->i_mapping, new_i_size + PAGE_SIZE - 1, 0, 1);
  	truncate_inode_pages(inode->i_mapping, new_i_size);
  
  	if (OCFS2_I(inode)->ip_dyn_features & OCFS2_INLINE_DATA_FL) {
  		status = ocfs2_truncate_inline(inode, di_bh, new_i_size,
  					       i_size_read(inode), 1);
  		if (status)
  			mlog_errno(status);
  
  		goto bail_unlock_sem;
  	}
  
  	/* 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_sem;
  	}
  
  	status = ocfs2_commit_truncate(osb, inode, di_bh);
  	if (status < 0) {
  		mlog_errno(status);
  		goto bail_unlock_sem;
  	}
  
  	/* TODO: orphan dir cleanup here. */
  bail_unlock_sem:
  	up_write(&OCFS2_I(inode)->ip_alloc_sem);
  
  bail:
  	if (!status && OCFS2_I(inode)->ip_clusters == 0)
  		status = ocfs2_try_remove_refcount_tree(inode, di_bh);
  
  	return status;
  }
  
  /*
   * extend file 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_add_inode_data(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 ret;
  	struct ocfs2_extent_tree et;
  
  	ocfs2_init_dinode_extent_tree(&et, INODE_CACHE(inode), fe_bh);
  	ret = ocfs2_add_clusters_in_btree(handle, &et, logical_offset,
  					  clusters_to_add, mark_unwritten,
  					  data_ac, meta_ac, reason_ret);
  
  	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);
  	struct ocfs2_extent_tree et;
  	int did_quota = 0;
  
  	/*
  	 * This function only exists for file systems which don't
  	 * support holes.
  	 */
  	BUG_ON(mark_unwritten && !ocfs2_sparse_alloc(osb));
  
  	status = ocfs2_read_inode_block(inode, &bh);
  	if (status < 0) {
  		mlog_errno(status);
  		goto leave;
  	}
  	fe = (struct ocfs2_dinode *) bh->b_data;
  
  restart_all:
  	BUG_ON(le32_to_cpu(fe->i_clusters) != OCFS2_I(inode)->ip_clusters);
  
  	ocfs2_init_dinode_extent_tree(&et, INODE_CACHE(inode), bh);
  	status = ocfs2_lock_allocators(inode, &et, clusters_to_add, 0,
  				       &data_ac, &meta_ac);
  	if (status) {
  		mlog_errno(status);
  		goto leave;
  	}
  
  	credits = ocfs2_calc_extend_credits(osb->sb, &fe->id2.i_list,
  					    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:
  	trace_ocfs2_extend_allocation(
  		(unsigned long long)OCFS2_I(inode)->ip_blkno,
  		(unsigned long long)i_size_read(inode),
  		le32_to_cpu(fe->i_clusters), clusters_to_add,
  		why, restart_func);
  
  	status = dquot_alloc_space_nodirty(inode,
  			ocfs2_clusters_to_bytes(osb->sb, clusters_to_add));
  	if (status)
  		goto leave;
  	did_quota = 1;
  
  	/* 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_di(handle, INODE_CACHE(inode), bh,
  					 OCFS2_JOURNAL_ACCESS_WRITE);
  	if (status < 0) {
  		mlog_errno(status);
  		goto leave;
  	}
  
  	prev_clusters = OCFS2_I(inode)->ip_clusters;
  
  	status = ocfs2_add_inode_data(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;
  	}
  
  	ocfs2_journal_dirty(handle, bh);
  
  	spin_lock(&OCFS2_I(inode)->ip_lock);
  	clusters_to_add -= (OCFS2_I(inode)->ip_clusters - prev_clusters);
  	spin_unlock(&OCFS2_I(inode)->ip_lock);
  	/* Release unused quota reservation */
  	dquot_free_space(inode,
  			ocfs2_clusters_to_bytes(osb->sb, clusters_to_add));
  	did_quota = 0;
  
  	if (why != RESTART_NONE && clusters_to_add) {
  		if (why == RESTART_META) {
  			restart_func = 1;
  			status = 0;
  		} else {
  			BUG_ON(why != RESTART_TRANS);
  
  			/* TODO: This can be more intelligent. */
  			credits = ocfs2_calc_extend_credits(osb->sb,
  							    &fe->id2.i_list,
  							    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;
  		}
  	}
  
  	trace_ocfs2_extend_allocation_end(OCFS2_I(inode)->ip_blkno,
  	     le32_to_cpu(fe->i_clusters),
  	     (unsigned long long)le64_to_cpu(fe->i_size),
  	     OCFS2_I(inode)->ip_clusters,
  	     (unsigned long long)i_size_read(inode));
  
  leave:
  	if (status < 0 && did_quota)
  		dquot_free_space(inode,
  			ocfs2_clusters_to_bytes(osb->sb, clusters_to_add));
  	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;
  	}
  	brelse(bh);
  	bh = NULL;
  
  	return status;
  }
  
  /*
   * While a write will already be ordering the data, a truncate will not.
   * Thus, we need to explicitly order the zeroed pages.
   */
  static handle_t *ocfs2_zero_start_ordered_transaction(struct inode *inode)
  {
  	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
  	handle_t *handle = NULL;
  	int ret = 0;
  
  	if (!ocfs2_should_order_data(inode))
  		goto out;
  
  	handle = ocfs2_start_trans(osb, OCFS2_INODE_UPDATE_CREDITS);
  	if (IS_ERR(handle)) {
  		ret = -ENOMEM;
  		mlog_errno(ret);
  		goto out;
  	}
  
  	ret = ocfs2_jbd2_file_inode(handle, inode);
  	if (ret < 0)
  		mlog_errno(ret);
  
  out:
  	if (ret) {
  		if (!IS_ERR(handle))
  			ocfs2_commit_trans(osb, handle);
  		handle = ERR_PTR(ret);
  	}
  	return handle;
  }
  
  /* 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 ->write_begin() and ->write_end(). */
  static int ocfs2_write_zero_page(struct inode *inode, u64 abs_from,
  				 u64 abs_to)
  {
  	struct address_space *mapping = inode->i_mapping;
  	struct page *page;
  	unsigned long index = abs_from >> PAGE_CACHE_SHIFT;
  	handle_t *handle = NULL;
  	int ret = 0;
  	unsigned zero_from, zero_to, block_start, block_end;
  
  	BUG_ON(abs_from >= abs_to);
  	BUG_ON(abs_to > (((u64)index + 1) << PAGE_CACHE_SHIFT));
  	BUG_ON(abs_from & (inode->i_blkbits - 1));
  
  	page = find_or_create_page(mapping, index, GFP_NOFS);
  	if (!page) {
  		ret = -ENOMEM;
  		mlog_errno(ret);
  		goto out;
  	}
  
  	/* Get the offsets within the page that we want to zero */
  	zero_from = abs_from & (PAGE_CACHE_SIZE - 1);
  	zero_to = abs_to & (PAGE_CACHE_SIZE - 1);
  	if (!zero_to)
  		zero_to = PAGE_CACHE_SIZE;
  
  	trace_ocfs2_write_zero_page(
  			(unsigned long long)OCFS2_I(inode)->ip_blkno,
  			(unsigned long long)abs_from,
  			(unsigned long long)abs_to,
  			index, zero_from, zero_to);
  
  	/* We know that zero_from is block aligned */
  	for (block_start = zero_from; block_start < zero_to;
  	     block_start = block_end) {
  		block_end = block_start + (1 << inode->i_blkbits);
  
  		/*
  		 * block_start is block-aligned.  Bump it by one to force
  		 * __block_write_begin and block_commit_write to zero the
  		 * whole block.
  		 */
  		ret = __block_write_begin(page, block_start + 1, 0,
  					  ocfs2_get_block);
  		if (ret < 0) {
  			mlog_errno(ret);
  			goto out_unlock;
  		}
  
  		if (!handle) {
  			handle = ocfs2_zero_start_ordered_transaction(inode);
  			if (IS_ERR(handle)) {
  				ret = PTR_ERR(handle);
  				handle = NULL;
  				break;
  			}
  		}
  
  		/* must not update i_size! */
  		ret = block_commit_write(page, block_start + 1,
  					 block_start + 1);
  		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;
  }
  
  /*
   * Find the next range to zero.  We do this in terms of bytes because
   * that's what ocfs2_zero_extend() wants, and it is dealing with the
   * pagecache.  We may return multiple extents.
   *
   * zero_start and zero_end are ocfs2_zero_extend()s current idea of what
   * needs to be zeroed.  range_start and range_end return the next zeroing
   * range.  A subsequent call should pass the previous range_end as its
   * zero_start.  If range_end is 0, there's nothing to do.
   *
   * Unwritten extents are skipped over.  Refcounted extents are CoWd.
   */
  static int ocfs2_zero_extend_get_range(struct inode *inode,
  				       struct buffer_head *di_bh,
  				       u64 zero_start, u64 zero_end,
  				       u64 *range_start, u64 *range_end)
  {
  	int rc = 0, needs_cow = 0;
  	u32 p_cpos, zero_clusters = 0;
  	u32 zero_cpos =
  		zero_start >> OCFS2_SB(inode->i_sb)->s_clustersize_bits;
  	u32 last_cpos = ocfs2_clusters_for_bytes(inode->i_sb, zero_end);
  	unsigned int num_clusters = 0;
  	unsigned int ext_flags = 0;
  
  	while (zero_cpos < last_cpos) {
  		rc = ocfs2_get_clusters(inode, zero_cpos, &p_cpos,
  					&num_clusters, &ext_flags);
  		if (rc) {
  			mlog_errno(rc);
  			goto out;
  		}
  
  		if (p_cpos && !(ext_flags & OCFS2_EXT_UNWRITTEN)) {
  			zero_clusters = num_clusters;
  			if (ext_flags & OCFS2_EXT_REFCOUNTED)
  				needs_cow = 1;
  			break;
  		}
  
  		zero_cpos += num_clusters;
  	}
  	if (!zero_clusters) {
  		*range_end = 0;
  		goto out;
  	}
  
  	while ((zero_cpos + zero_clusters) < last_cpos) {
  		rc = ocfs2_get_clusters(inode, zero_cpos + zero_clusters,
  					&p_cpos, &num_clusters,
  					&ext_flags);
  		if (rc) {
  			mlog_errno(rc);
  			goto out;
  		}
  
  		if (!p_cpos || (ext_flags & OCFS2_EXT_UNWRITTEN))
  			break;
  		if (ext_flags & OCFS2_EXT_REFCOUNTED)
  			needs_cow = 1;
  		zero_clusters += num_clusters;
  	}
  	if ((zero_cpos + zero_clusters) > last_cpos)
  		zero_clusters = last_cpos - zero_cpos;
  
  	if (needs_cow) {
  		rc = ocfs2_refcount_cow(inode, NULL, di_bh, zero_cpos,
  					zero_clusters, UINT_MAX);
  		if (rc) {
  			mlog_errno(rc);
  			goto out;
  		}
  	}
  
  	*range_start = ocfs2_clusters_to_bytes(inode->i_sb, zero_cpos);
  	*range_end = ocfs2_clusters_to_bytes(inode->i_sb,
  					     zero_cpos + zero_clusters);
  
  out:
  	return rc;
  }
  
  /*
   * Zero one range returned from ocfs2_zero_extend_get_range().  The caller
   * has made sure that the entire range needs zeroing.
   */
  static int ocfs2_zero_extend_range(struct inode *inode, u64 range_start,
  				   u64 range_end)
  {
  	int rc = 0;
  	u64 next_pos;
  	u64 zero_pos = range_start;
  
  	trace_ocfs2_zero_extend_range(
  			(unsigned long long)OCFS2_I(inode)->ip_blkno,
  			(unsigned long long)range_start,
  			(unsigned long long)range_end);
  	BUG_ON(range_start >= range_end);
  
  	while (zero_pos < range_end) {
  		next_pos = (zero_pos & PAGE_CACHE_MASK) + PAGE_CACHE_SIZE;
  		if (next_pos > range_end)
  			next_pos = range_end;
  		rc = ocfs2_write_zero_page(inode, zero_pos, next_pos);
  		if (rc < 0) {
  			mlog_errno(rc);
  			break;
  		}
  		zero_pos = next_pos;
  
  		/*
  		 * Very large extends have the potential to lock up
  		 * the cpu for extended periods of time.
  		 */
  		cond_resched();
  	}
  
  	return rc;
  }
  
  int ocfs2_zero_extend(struct inode *inode, struct buffer_head *di_bh,
  		      loff_t zero_to_size)
  {
  	int ret = 0;
  	u64 zero_start, range_start = 0, range_end = 0;
  	struct super_block *sb = inode->i_sb;
  
  	zero_start = ocfs2_align_bytes_to_blocks(sb, i_size_read(inode));
  	trace_ocfs2_zero_extend((unsigned long long)OCFS2_I(inode)->ip_blkno,
  				(unsigned long long)zero_start,
  				(unsigned long long)i_size_read(inode));
  	while (zero_start < zero_to_size) {
  		ret = ocfs2_zero_extend_get_range(inode, di_bh, zero_start,
  						  zero_to_size,
  						  &range_start,
  						  &range_end);
  		if (ret) {
  			mlog_errno(ret);
  			break;
  		}
  		if (!range_end)
  			break;
  		/* Trim the ends */
  		if (range_start < zero_start)
  			range_start = zero_start;
  		if (range_end > zero_to_size)
  			range_end = zero_to_size;
  
  		ret = ocfs2_zero_extend_range(inode, range_start,
  					      range_end);
  		if (ret) {
  			mlog_errno(ret);
  			break;
  		}
  		zero_start = range_end;
  	}
  
  	return ret;
  }
  
  int ocfs2_extend_no_holes(struct inode *inode, struct buffer_head *di_bh,
  			  u64 new_i_size, u64 zero_to)
  {
  	int ret;
  	u32 clusters_to_add;
  	struct ocfs2_inode_info *oi = OCFS2_I(inode);
  
  	/*
  	 * Only quota files call this without a bh, and they can't be
  	 * refcounted.
  	 */
  	BUG_ON(!di_bh && (oi->ip_dyn_features & OCFS2_HAS_REFCOUNT_FL));
  	BUG_ON(!di_bh && !(oi->ip_flags & OCFS2_INODE_SYSTEM_FILE));
  
  	clusters_to_add = ocfs2_clusters_for_bytes(inode->i_sb, new_i_size);
  	if (clusters_to_add < oi->ip_clusters)
  		clusters_to_add = 0;
  	else
  		clusters_to_add -= oi->ip_clusters;
  
  	if (clusters_to_add) {
  		ret = __ocfs2_extend_allocation(inode, oi->ip_clusters,
  						clusters_to_add, 0);
  		if (ret) {
  			mlog_errno(ret);
  			goto out;
  		}
  	}
  
  	/*
  	 * 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, di_bh, zero_to);
  	if (ret < 0)
  		mlog_errno(ret);
  
  out:
  	return ret;
  }
  
  static int ocfs2_extend_file(struct inode *inode,
  			     struct buffer_head *di_bh,
  			     u64 new_i_size)
  {
  	int ret = 0;
  	struct ocfs2_inode_info *oi = OCFS2_I(inode);
  
  	BUG_ON(!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));
  
  	/*
  	 * The alloc sem blocks people 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.  We even have to hold it for sparse files because there
  	 * might be some tail zeroing.
  	 */
  	down_write(&oi->ip_alloc_sem);
  
  	if (oi->ip_dyn_features & OCFS2_INLINE_DATA_FL) {
  		/*
  		 * We can optimize small extends by keeping the inodes
  		 * inline data.
  		 */
  		if (ocfs2_size_fits_inline_data(di_bh, new_i_size)) {
  			up_write(&oi->ip_alloc_sem);
  			goto out_update_size;
  		}
  
  		ret = ocfs2_convert_inline_data_to_extents(inode, di_bh);
  		if (ret) {
  			up_write(&oi->ip_alloc_sem);
  			mlog_errno(ret);
  			goto out;
  		}
  	}
  
  	if (ocfs2_sparse_alloc(OCFS2_SB(inode->i_sb)))
  		ret = ocfs2_zero_extend(inode, di_bh, new_i_size);
  	else
  		ret = ocfs2_extend_no_holes(inode, di_bh, new_i_size,
  					    new_i_size);
  
  	up_write(&oi->ip_alloc_sem);
  
  	if (ret < 0) {
  		mlog_errno(ret);
  		goto out;
  	}
  
  out_update_size:
  	ret = ocfs2_simple_size_update(inode, di_bh, new_i_size);
  	if (ret < 0)
  		mlog_errno(ret);
  
  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;
  	struct dquot *transfer_to[MAXQUOTAS] = { };
  	int qtype;
  
  	trace_ocfs2_setattr(inode, dentry,
  			    (unsigned long long)OCFS2_I(inode)->ip_blkno,
  			    dentry->d_name.len, dentry->d_name.name,
  			    attr->ia_valid, attr->ia_mode,
  			    attr->ia_uid, attr->ia_gid);
  
  	/* ensuring we don't even attempt to truncate a symlink */
  	if (S_ISLNK(inode->i_mode))
  		attr->ia_valid &= ~ATTR_SIZE;
  
  #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))
  		return 0;
  
  	status = inode_change_ok(inode, attr);
  	if (status)
  		return status;
  
  	if (is_quota_modification(inode, attr))
  		dquot_initialize(inode);
  	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_inode_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)) {
  		status = inode_newsize_ok(inode, attr->ia_size);
  		if (status)
  			goto bail_unlock;
  
  		inode_dio_wait(inode);
  
  		if (i_size_read(inode) > attr->ia_size) {
  			if (ocfs2_should_order_data(inode)) {
  				status = ocfs2_begin_ordered_truncate(inode,
  								      attr->ia_size);
  				if (status)
  					goto bail_unlock;
  			}
  			status = ocfs2_truncate_file(inode, bh, attr->ia_size);
  		} else
  			status = ocfs2_extend_file(inode, bh, attr->ia_size);
  		if (status < 0) {
  			if (status != -ENOSPC)
  				mlog_errno(status);
  			status = -ENOSPC;
  			goto bail_unlock;
  		}
  	}
  
  	if ((attr->ia_valid & ATTR_UID && attr->ia_uid != inode->i_uid) ||
  	    (attr->ia_valid & ATTR_GID && attr->ia_gid != inode->i_gid)) {
  		/*
  		 * Gather pointers to quota structures so that allocation /
  		 * freeing of quota structures happens here and not inside
  		 * dquot_transfer() where we have problems with lock ordering
  		 */
  		if (attr->ia_valid & ATTR_UID && attr->ia_uid != inode->i_uid
  		    && OCFS2_HAS_RO_COMPAT_FEATURE(sb,
  		    OCFS2_FEATURE_RO_COMPAT_USRQUOTA)) {
  			transfer_to[USRQUOTA] = dqget(sb, attr->ia_uid,
  						      USRQUOTA);
  			if (!transfer_to[USRQUOTA]) {
  				status = -ESRCH;
  				goto bail_unlock;
  			}
  		}
  		if (attr->ia_valid & ATTR_GID && attr->ia_gid != inode->i_gid
  		    && OCFS2_HAS_RO_COMPAT_FEATURE(sb,
  		    OCFS2_FEATURE_RO_COMPAT_GRPQUOTA)) {
  			transfer_to[GRPQUOTA] = dqget(sb, attr->ia_gid,
  						      GRPQUOTA);
  			if (!transfer_to[GRPQUOTA]) {
  				status = -ESRCH;
  				goto bail_unlock;
  			}
  		}
  		handle = ocfs2_start_trans(osb, OCFS2_INODE_UPDATE_CREDITS +
  					   2 * ocfs2_quota_trans_credits(sb));
  		if (IS_ERR(handle)) {
  			status = PTR_ERR(handle);
  			mlog_errno(status);
  			goto bail_unlock;
  		}
  		status = __dquot_transfer(inode, transfer_to);
  		if (status < 0)
  			goto bail_commit;
  	} else {
  		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 truncate_setsize(),
  	 * 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.
  	 *
  	 * XXX: this means the conditional below can probably be removed.
  	 */
  	if ((attr->ia_valid & ATTR_SIZE) &&
  	    attr->ia_size != i_size_read(inode)) {
  		status = vmtruncate(inode, attr->ia_size);
  		if (status) {
  			mlog_errno(status);
  			goto bail_commit;
  		}
  	}
  
  	setattr_copy(inode, attr);
  	mark_inode_dirty(inode);
  
  	status = ocfs2_mark_inode_dirty(handle, inode, bh);
  	if (status < 0)
  		mlog_errno(status);
  
  bail_commit:
  	ocfs2_commit_trans(osb, handle);
  bail_unlock:
  	ocfs2_inode_unlock(inode, 1);
  bail_unlock_rw:
  	if (size_change)
  		ocfs2_rw_unlock(inode, 1);
  bail:
  	brelse(bh);
  
  	/* Release quota pointers in case we acquired them */
  	for (qtype = 0; qtype < MAXQUOTAS; qtype++)
  		dqput(transfer_to[qtype]);
  
  	if (!status && attr->ia_valid & ATTR_MODE) {
  		status = ocfs2_acl_chmod(inode);
  		if (status < 0)
  			mlog_errno(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;
  
  	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:
  	return err;
  }
  
  int ocfs2_permission(struct inode *inode, int mask)
  {
  	int ret;
  
  	if (mask & MAY_NOT_BLOCK)
  		return -ECHILD;
  
  	ret = ocfs2_inode_lock(inode, NULL, 0);
  	if (ret) {
  		if (ret != -ENOENT)
  			mlog_errno(ret);
  		goto out;
  	}
  
  	ret = generic_permission(inode, mask);
  
  	ocfs2_inode_unlock(inode, 0);
  out:
  	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;
  
  	trace_ocfs2_write_remove_suid(
  			(unsigned long long)OCFS2_I(inode)->ip_blkno,
  			inode->i_mode);
  
  	handle = ocfs2_start_trans(osb, OCFS2_INODE_UPDATE_CREDITS);
  	if (IS_ERR(handle)) {
  		ret = PTR_ERR(handle);
  		mlog_errno(ret);
  		goto out;
  	}
  
  	ret = ocfs2_journal_access_di(handle, INODE_CACHE(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);
  
  	ocfs2_journal_dirty(handle, bh);
  
  out_trans:
  	ocfs2_commit_trans(osb, handle);
  out:
  	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;
  
  	ret = ocfs2_read_inode_block(inode, &bh);
  	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;
  	u64 end = start + len;
  	struct buffer_head *di_bh = NULL;
  
  	if (OCFS2_I(inode)->ip_dyn_features & OCFS2_INLINE_DATA_FL) {
  		ret = ocfs2_read_inode_block(inode, &di_bh);
  		if (ret) {
  			mlog_errno(ret);
  			goto out;
  		}
  
  		/*
  		 * Nothing to do if the requested reservation range
  		 * fits within the inode.
  		 */
  		if (ocfs2_size_fits_inline_data(di_bh, end))
  			goto out;
  
  		ret = ocfs2_convert_inline_data_to_extents(inode, di_bh);
  		if (ret) {
  			mlog_errno(ret);
  			goto out;
  		}
  	}
  
  	/*
  	 * 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:
  
  	brelse(di_bh);
  	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.
  	 */
  	trace_ocfs2_zero_partial_clusters(
  		(unsigned long long)OCFS2_I(inode)->ip_blkno,
  		(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 (IS_ERR(handle)) {
  		ret = PTR_ERR(handle);
  		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;
  
  	trace_ocfs2_zero_partial_clusters_range1((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);
  
  		trace_ocfs2_zero_partial_clusters_range2(
  			(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_find_rec(struct ocfs2_extent_list *el, u32 pos)
  {
  	int i;
  	struct ocfs2_extent_rec *rec = NULL;
  
  	for (i = le16_to_cpu(el->l_next_free_rec) - 1; i >= 0; i--) {
  
  		rec = &el->l_recs[i];
  
  		if (le32_to_cpu(rec->e_cpos) < pos)
  			break;
  	}
  
  	return i;
  }
  
  /*
   * Helper to calculate the punching pos and length in one run, we handle the
   * following three cases in order:
   *
   * - remove the entire record
   * - remove a partial record
   * - no record needs to be removed (hole-punching completed)
  */
  static void ocfs2_calc_trunc_pos(struct inode *inode,
  				 struct ocfs2_extent_list *el,
  				 struct ocfs2_extent_rec *rec,
  				 u32 trunc_start, u32 *trunc_cpos,
  				 u32 *trunc_len, u32 *trunc_end,
  				 u64 *blkno, int *done)
  {
  	int ret = 0;
  	u32 coff, range;
  
  	range = le32_to_cpu(rec->e_cpos) + ocfs2_rec_clusters(el, rec);
  
  	if (le32_to_cpu(rec->e_cpos) >= trunc_start) {
  		/*
  		 * remove an entire extent record.
  		 */
  		*trunc_cpos = le32_to_cpu(rec->e_cpos);
  		/*
  		 * Skip holes if any.
  		 */
  		if (range < *trunc_end)
  			*trunc_end = range;
  		*trunc_len = *trunc_end - le32_to_cpu(rec->e_cpos);
  		*blkno = le64_to_cpu(rec->e_blkno);
  		*trunc_end = le32_to_cpu(rec->e_cpos);
  	} else if (range > trunc_start) {
  		/*
  		 * remove a partial extent record, which means we're
  		 * removing the last extent record.
  		 */
  		*trunc_cpos = trunc_start;
  		/*
  		 * skip hole if any.
  		 */
  		if (range < *trunc_end)
  			*trunc_end = range;
  		*trunc_len = *trunc_end - trunc_start;
  		coff = trunc_start - le32_to_cpu(rec->e_cpos);
  		*blkno = le64_to_cpu(rec->e_blkno) +
  				ocfs2_clusters_to_blocks(inode->i_sb, coff);
  		*trunc_end = trunc_start;
  	} else {
  		/*
  		 * It may have two following possibilities:
  		 *
  		 * - last record has been removed
  		 * - trunc_start was within a hole
  		 *
  		 * both two cases mean the completion of hole punching.
  		 */
  		ret = 1;
  	}
  
  	*done = ret;
  }
  
  static int ocfs2_remove_inode_range(struct inode *inode,
  				    struct buffer_head *di_bh, u64 byte_start,
  				    u64 byte_len)
  {
  	int ret = 0, flags = 0, done = 0, i;
  	u32 trunc_start, trunc_len, trunc_end, trunc_cpos, phys_cpos;
  	u32 cluster_in_el;
  	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
  	struct ocfs2_cached_dealloc_ctxt dealloc;
  	struct address_space *mapping = inode->i_mapping;
  	struct ocfs2_extent_tree et;
  	struct ocfs2_path *path = NULL;
  	struct ocfs2_extent_list *el = NULL;
  	struct ocfs2_extent_rec *rec = NULL;
  	struct ocfs2_dinode *di = (struct ocfs2_dinode *)di_bh->b_data;
  	u64 blkno, refcount_loc = le64_to_cpu(di->i_refcount_loc);
  
  	ocfs2_init_dinode_extent_tree(&et, INODE_CACHE(inode), di_bh);
  	ocfs2_init_dealloc_ctxt(&dealloc);
  
  	trace_ocfs2_remove_inode_range(
  			(unsigned long long)OCFS2_I(inode)->ip_blkno,
  			(unsigned long long)byte_start,
  			(unsigned long long)byte_len);
  
  	if (byte_len == 0)
  		return 0;
  
  	if (OCFS2_I(inode)->ip_dyn_features & OCFS2_INLINE_DATA_FL) {
  		ret = ocfs2_truncate_inline(inode, di_bh, byte_start,
  					    byte_start + byte_len, 0);
  		if (ret) {
  			mlog_errno(ret);
  			goto out;
  		}
  		/*
  		 * There's no need to get fancy with the page cache
  		 * truncate of an inline-data inode. We're talking
  		 * about less than a page here, which will be cached
  		 * in the dinode buffer anyway.
  		 */
  		unmap_mapping_range(mapping, 0, 0, 0);
  		truncate_inode_pages(mapping, 0);
  		goto out;
  	}
  
  	/*
  	 * For reflinks, we may need to CoW 2 clusters which might be
  	 * partially zero'd later, if hole's start and end offset were
  	 * within one cluster(means is not exactly aligned to clustersize).
  	 */
  
  	if (OCFS2_I(inode)->ip_dyn_features & OCFS2_HAS_REFCOUNT_FL) {
  
  		ret = ocfs2_cow_file_pos(inode, di_bh, byte_start);
  		if (ret) {
  			mlog_errno(ret);
  			goto out;
  		}
  
  		ret = ocfs2_cow_file_pos(inode, di_bh, byte_start + byte_len);
  		if (ret) {
  			mlog_errno(ret);
  			goto out;
  		}
  	}
  
  	trunc_start = ocfs2_clusters_for_bytes(osb->sb, byte_start);
  	trunc_end = (byte_start + byte_len) >> osb->s_clustersize_bits;
  	cluster_in_el = trunc_end;
  
  	ret = ocfs2_zero_partial_clusters(inode, byte_start, byte_len);
  	if (ret) {
  		mlog_errno(ret);
  		goto out;
  	}
  
  	path = ocfs2_new_path_from_et(&et);
  	if (!path) {
  		ret = -ENOMEM;
  		mlog_errno(ret);
  		goto out;
  	}
  
  	while (trunc_end > trunc_start) {
  
  		ret = ocfs2_find_path(INODE_CACHE(inode), path,
  				      cluster_in_el);
  		if (ret) {
  			mlog_errno(ret);
  			goto out;
  		}
  
  		el = path_leaf_el(path);
  
  		i = ocfs2_find_rec(el, trunc_end);
  		/*
  		 * Need to go to previous extent block.
  		 */
  		if (i < 0) {
  			if (path->p_tree_depth == 0)
  				break;
  
  			ret = ocfs2_find_cpos_for_left_leaf(inode->i_sb,
  							    path,
  							    &cluster_in_el);
  			if (ret) {
  				mlog_errno(ret);
  				goto out;
  			}
  
  			/*
  			 * We've reached the leftmost extent block,
  			 * it's safe to leave.
  			 */
  			if (cluster_in_el == 0)
  				break;
  
  			/*
  			 * The 'pos' searched for previous extent block is
  			 * always one cluster less than actual trunc_end.
  			 */
  			trunc_end = cluster_in_el + 1;
  
  			ocfs2_reinit_path(path, 1);
  
  			continue;
  
  		} else
  			rec = &el->l_recs[i];
  
  		ocfs2_calc_trunc_pos(inode, el, rec, trunc_start, &trunc_cpos,
  				     &trunc_len, &trunc_end, &blkno, &done);
  		if (done)
  			break;
  
  		flags = rec->e_flags;
  		phys_cpos = ocfs2_blocks_to_clusters(inode->i_sb, blkno);
  
  		ret = ocfs2_remove_btree_range(inode, &et, trunc_cpos,
  					       phys_cpos, trunc_len, flags,
  					       &dealloc, refcount_loc);
  		if (ret < 0) {
  			mlog_errno(ret);
  			goto out;
  		}
  
  		cluster_in_el = trunc_end;
  
  		ocfs2_reinit_path(path, 1);
  	}
  
  	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 = inode->i_sb->s_maxbytes;
  
  	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_inode_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_inode_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_inode_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_inode_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_inode_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_inode_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_inode_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_inode_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);
  
  	if (file->f_flags & O_SYNC)
  		handle->h_sync = 1;
  
  	ocfs2_commit_trans(osb, handle);
  
  out_inode_unlock:
  	brelse(di_bh);
  	ocfs2_inode_unlock(inode, 1);
  out_rw_unlock:
  	ocfs2_rw_unlock(inode, 1);
  
  out:
  	mutex_unlock(&inode->i_mutex);
  	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 file *file, int mode, loff_t offset,
  			    loff_t len)
  {
  	struct inode *inode = file->f_path.dentry->d_inode;
  	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
  	struct ocfs2_space_resv sr;
  	int change_size = 1;
  	int cmd = OCFS2_IOC_RESVSP64;
  
  	if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE))
  		return -EOPNOTSUPP;
  	if (!ocfs2_writes_unwritten_extents(osb))
  		return -EOPNOTSUPP;
  
  	if (mode & FALLOC_FL_KEEP_SIZE)
  		change_size = 0;
  
  	if (mode & FALLOC_FL_PUNCH_HOLE)
  		cmd = OCFS2_IOC_UNRESVSP64;
  
  	sr.l_whence = 0;
  	sr.l_start = (s64)offset;
  	sr.l_len = (s64)len;
  
  	return __ocfs2_change_file_space(NULL, inode, offset, cmd, &sr,
  					 change_size);
  }
  
  int ocfs2_check_range_for_refcount(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;
  
  	if (!ocfs2_refcount_tree(OCFS2_SB(inode->i_sb)) ||
  	    !(OCFS2_I(inode)->ip_dyn_features & OCFS2_HAS_REFCOUNT_FL) ||
  	    OCFS2_I(inode)->ip_dyn_features & OCFS2_INLINE_DATA_FL)
  		return 0;
  
  	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 && (extent_flags & OCFS2_EXT_REFCOUNTED)) {
  			ret = 1;
  			break;
  		}
  
  		if (extent_len > clusters)
  			extent_len = clusters;
  
  		clusters -= extent_len;
  		cpos += extent_len;
  	}
  out:
  	return ret;
  }
  
  static void ocfs2_aiodio_wait(struct inode *inode)
  {
  	wait_queue_head_t *wq = ocfs2_ioend_wq(inode);
  
  	wait_event(*wq, (atomic_read(&OCFS2_I(inode)->ip_unaligned_aio) == 0));
  }
  
  static int ocfs2_is_io_unaligned(struct inode *inode, size_t count, loff_t pos)
  {
  	int blockmask = inode->i_sb->s_blocksize - 1;
  	loff_t final_size = pos + count;
  
  	if ((pos & blockmask) || (final_size & blockmask))
  		return 1;
  	return 0;
  }
  
  static int ocfs2_prepare_inode_for_refcount(struct inode *inode,
  					    struct file *file,
  					    loff_t pos, size_t count,
  					    int *meta_level)
  {
  	int ret;
  	struct buffer_head *di_bh = NULL;
  	u32 cpos = pos >> OCFS2_SB(inode->i_sb)->s_clustersize_bits;
  	u32 clusters =
  		ocfs2_clusters_for_bytes(inode->i_sb, pos + count) - cpos;
  
  	ret = ocfs2_inode_lock(inode, &di_bh, 1);
  	if (ret) {
  		mlog_errno(ret);
  		goto out;
  	}
  
  	*meta_level = 1;
  
  	ret = ocfs2_refcount_cow(inode, file, di_bh, cpos, clusters, UINT_MAX);
  	if (ret)
  		mlog_errno(ret);
  out:
  	brelse(di_bh);
  	return ret;
  }
  
  static int ocfs2_prepare_inode_for_write(struct file *file,
  					 loff_t *ppos,
  					 size_t count,
  					 int appending,
  					 int *direct_io,
  					 int *has_refcount)
  {
  	int ret = 0, meta_level = 0;
  	struct dentry *dentry = file->f_path.dentry;
  	struct inode *inode = dentry->d_inode;
  	loff_t saved_pos = 0, end;
  
  	/*
  	 * We start with a read level meta lock and only jump to an ex
  	 * if we need to make modifications here.
  	 */
  	for(;;) {
  		ret = ocfs2_inode_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
  		 * proceed, 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_inode_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);
  		else
  			saved_pos = *ppos;
  
  		end = saved_pos + count;
  
  		ret = ocfs2_check_range_for_refcount(inode, saved_pos, count);
  		if (ret == 1) {
  			ocfs2_inode_unlock(inode, meta_level);
  			meta_level = -1;
  
  			ret = ocfs2_prepare_inode_for_refcount(inode,
  							       file,
  							       saved_pos,
  							       count,
  							       &meta_level);
  			if (has_refcount)
  				*has_refcount = 1;
  			if (direct_io)
  				*direct_io = 0;
  		}
  
  		if (ret < 0) {
  			mlog_errno(ret);
  			goto out_unlock;
  		}
  
  		/*
  		 * Skip the O_DIRECT checks if we don't need
  		 * them.
  		 */
  		if (!direct_io || !(*direct_io))
  			break;
  
  		/*
  		 * There's no sane way to do direct writes to an inode
  		 * with inline data.
  		 */
  		if (OCFS2_I(inode)->ip_dyn_features & OCFS2_INLINE_DATA_FL) {
  			*direct_io = 0;
  			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;
  	}
  
  	if (appending)
  		*ppos = saved_pos;
  
  out_unlock:
  	trace_ocfs2_prepare_inode_for_write(OCFS2_I(inode)->ip_blkno,
  					    saved_pos, appending, count,
  					    direct_io, has_refcount);
  
  	if (meta_level >= 0)
  		ocfs2_inode_unlock(inode, meta_level);
  
  out:
  	return 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, has_refcount = 0;
  	ssize_t written = 0;
  	size_t ocount;		/* original count */
  	size_t count;		/* after file limit checks */
  	loff_t old_size, *ppos = &iocb->ki_pos;
  	u32 old_clusters;
  	struct file *file = iocb->ki_filp;
  	struct inode *inode = file->f_path.dentry->d_inode;
  	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
  	int full_coherency = !(osb->s_mount_opt &
  			       OCFS2_MOUNT_COHERENCY_BUFFERED);
  	int unaligned_dio = 0;
  
  	trace_ocfs2_file_aio_write(inode, file, file->f_path.dentry,
  		(unsigned long long)OCFS2_I(inode)->ip_blkno,
  		file->f_path.dentry->d_name.len,
  		file->f_path.dentry->d_name.name,
  		(unsigned int)nr_segs);
  
  	if (iocb->ki_left == 0)
  		return 0;
  
  	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);
  
  	ocfs2_iocb_clear_sem_locked(iocb);
  
  relock:
  	/* to match setattr's i_mutex -> rw_lock ordering */
  	if (direct_io) {
  		have_alloc_sem = 1;
  		/* communicate with ocfs2_dio_end_io */
  		ocfs2_iocb_set_sem_locked(iocb);
  	}
  
  	/*
  	 * Concurrent O_DIRECT writes are allowed with
  	 * mount_option "coherency=buffered".
  	 */
  	rw_level = (!direct_io || full_coherency);
  
  	ret = ocfs2_rw_lock(inode, rw_level);
  	if (ret < 0) {
  		mlog_errno(ret);
  		goto out_sems;
  	}
  
  	/*
  	 * O_DIRECT writes with "coherency=full" need to take EX cluster
  	 * inode_lock to guarantee coherency.
  	 */
  	if (direct_io && full_coherency) {
  		/*
  		 * We need to take and drop the inode lock to force
  		 * other nodes to drop their caches.  Buffered I/O
  		 * already does this in write_begin().
  		 */
  		ret = ocfs2_inode_lock(inode, NULL, 1);
  		if (ret < 0) {
  			mlog_errno(ret);
  			goto out_sems;
  		}
  
  		ocfs2_inode_unlock(inode, 1);
  	}
  
  	can_do_direct = direct_io;
  	ret = ocfs2_prepare_inode_for_write(file, ppos,
  					    iocb->ki_left, appending,
  					    &can_do_direct, &has_refcount);
  	if (ret < 0) {
  		mlog_errno(ret);
  		goto out;
  	}
  
  	if (direct_io && !is_sync_kiocb(iocb))
  		unaligned_dio = ocfs2_is_io_unaligned(inode, iocb->ki_left,
  						      *ppos);
  
  	/*
  	 * 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);
  
  		have_alloc_sem = 0;
  		rw_level = -1;
  
  		direct_io = 0;
  		goto relock;
  	}
  
  	if (unaligned_dio) {
  		/*
  		 * Wait on previous unaligned aio to complete before
  		 * proceeding.
  		 */
  		ocfs2_aiodio_wait(inode);
  
  		/* Mark the iocb as needing a decrement in ocfs2_dio_end_io */
  		atomic_inc(&OCFS2_I(inode)->ip_unaligned_aio);
  		ocfs2_iocb_set_unaligned_aio(iocb);
  	}
  
  	/*
  	 * To later detect whether a journal commit for sync writes is
  	 * necessary, we sample i_size, and cluster count here.
  	 */
  	old_size = i_size_read(inode);
  	old_clusters = OCFS2_I(inode)->ip_clusters;
  
  	/* communicate with ocfs2_dio_end_io */
  	ocfs2_iocb_set_rw_locked(iocb, rw_level);
  
  	ret = generic_segment_checks(iov, &nr_segs, &ocount,
  				     VERIFY_READ);
  	if (ret)
  		goto out_dio;
  
  	count = ocount;
  	ret = generic_write_checks(file, ppos, &count,
  				   S_ISBLK(inode->i_mode));
  	if (ret)
  		goto out_dio;
  
  	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 {
  		current->backing_dev_info = file->f_mapping->backing_dev_info;
  		written = generic_file_buffered_write(iocb, iov, nr_segs, *ppos,
  						      ppos, count, 0);
  		current->backing_dev_info = NULL;
  	}
  
  out_dio:
  	/* buffered aio wouldn't have proper lock coverage today */
  	BUG_ON(ret == -EIOCBQUEUED && !(file->f_flags & O_DIRECT));
  
  	if (((file->f_flags & O_DSYNC) && !direct_io) || IS_SYNC(inode) ||
  	    ((file->f_flags & O_DIRECT) && !direct_io)) {
  		ret = filemap_fdatawrite_range(file->f_mapping, pos,
  					       pos + count - 1);
  		if (ret < 0)
  			written = ret;
  
  		if (!ret && ((old_size != i_size_read(inode)) ||
  			     (old_clusters != OCFS2_I(inode)->ip_clusters) ||
  			     has_refcount)) {
  			ret = jbd2_journal_force_commit(osb->journal->j_journal);
  			if (ret < 0)
  				written = ret;
  		}
  
  		if (!ret)
  			ret = filemap_fdatawait_range(file->f_mapping, pos,
  						      pos + count - 1);
  	}
  
  	/*
  	 * 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.
  	 * 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;
  		unaligned_dio = 0;
  	}
  
  	if (unaligned_dio)
  		atomic_dec(&OCFS2_I(inode)->ip_unaligned_aio);
  
  out:
  	if (rw_level != -1)
  		ocfs2_rw_unlock(inode, rw_level);
  
  out_sems:
  	if (have_alloc_sem)
  		ocfs2_iocb_clear_sem_locked(iocb);
  
  	mutex_unlock(&inode->i_mutex);
  
  	if (written)
  		ret = written;
  	return ret;
  }
  
  static int ocfs2_splice_to_file(struct pipe_inode_info *pipe,
  				struct file *out,
  				struct splice_desc *sd)
  {
  	int ret;
  
  	ret = ocfs2_prepare_inode_for_write(out, &sd->pos,
  					    sd->total_len, 0, NULL, NULL);
  	if (ret < 0) {
  		mlog_errno(ret);
  		return ret;
  	}
  
  	return splice_from_pipe_feed(pipe, sd, pipe_to_file);
  }
  
  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 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,
  	};
  
  
  	trace_ocfs2_file_splice_write(inode, out, out->f_path.dentry,
  			(unsigned long long)OCFS2_I(inode)->ip_blkno,
  			out->f_path.dentry->d_name.len,
  			out->f_path.dentry->d_name.name, len);
  
  	if (pipe->inode)
  		mutex_lock_nested(&pipe->inode->i_mutex, I_MUTEX_PARENT);
  
  	splice_from_pipe_begin(&sd);
  	do {
  		ret = splice_from_pipe_next(pipe, &sd);
  		if (ret <= 0)
  			break;
  
  		mutex_lock_nested(&inode->i_mutex, I_MUTEX_CHILD);
  		ret = ocfs2_rw_lock(inode, 1);
  		if (ret < 0)
  			mlog_errno(ret);
  		else {
  			ret = ocfs2_splice_to_file(pipe, out, &sd);
  			ocfs2_rw_unlock(inode, 1);
  		}
  		mutex_unlock(&inode->i_mutex);
  	} while (ret > 0);
  	splice_from_pipe_end(pipe, &sd);
  
  	if (pipe->inode)
  		mutex_unlock(&pipe->inode->i_mutex);
  
  	if (sd.num_spliced)
  		ret = sd.num_spliced;
  
  	if (ret > 0) {
  		unsigned long nr_pages;
  		int err;
  
  		nr_pages = (ret + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
  
  		err = generic_write_sync(out, *ppos, ret);
  		if (err)
  			ret = err;
  		else
  			*ppos += ret;
  
  		balance_dirty_pages_ratelimited_nr(mapping, nr_pages);
  	}
  
  	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, lock_level = 0;
  	struct inode *inode = in->f_path.dentry->d_inode;
  
  	trace_ocfs2_file_splice_read(inode, in, in->f_path.dentry,
  			(unsigned long long)OCFS2_I(inode)->ip_blkno,
  			in->f_path.dentry->d_name.len,
  			in->f_path.dentry->d_name.name, len);
  
  	/*
  	 * See the comment in ocfs2_file_aio_read()
  	 */
  	ret = ocfs2_inode_lock_atime(inode, in->f_vfsmnt, &lock_level);
  	if (ret < 0) {
  		mlog_errno(ret);
  		goto bail;
  	}
  	ocfs2_inode_unlock(inode, lock_level);
  
  	ret = generic_file_splice_read(in, ppos, pipe, len, flags);
  
  bail:
  	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;
  
  	trace_ocfs2_file_aio_read(inode, filp, filp->f_path.dentry,
  			(unsigned long long)OCFS2_I(inode)->ip_blkno,
  			filp->f_path.dentry->d_name.len,
  			filp->f_path.dentry->d_name.name, nr_segs);
  
  
  	if (!inode) {
  		ret = -EINVAL;
  		mlog_errno(ret);
  		goto bail;
  	}
  
  	ocfs2_iocb_clear_sem_locked(iocb);
  
  	/*
  	 * 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) {
  		have_alloc_sem = 1;
  		ocfs2_iocb_set_sem_locked(iocb);
  
  		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_inode_lock_atime(inode, filp->f_vfsmnt, &lock_level);
  	if (ret < 0) {
  		mlog_errno(ret);
  		goto bail;
  	}
  	ocfs2_inode_unlock(inode, lock_level);
  
  	ret = generic_file_aio_read(iocb, iov, nr_segs, iocb->ki_pos);
  	trace_generic_file_aio_read_ret(ret);
  
  	/* 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)
  		ocfs2_iocb_clear_sem_locked(iocb);
  
  	if (rw_level != -1)
  		ocfs2_rw_unlock(inode, rw_level);
  
  	return ret;
  }
  
  /* Refer generic_file_llseek_unlocked() */
  static loff_t ocfs2_file_llseek(struct file *file, loff_t offset, int origin)
  {
  	struct inode *inode = file->f_mapping->host;
  	int ret = 0;
  
  	mutex_lock(&inode->i_mutex);
  
  	switch (origin) {
  	case SEEK_SET:
  		break;
  	case SEEK_END:
  		offset += inode->i_size;
  		break;
  	case SEEK_CUR:
  		if (offset == 0) {
  			offset = file->f_pos;
  			goto out;
  		}
  		offset += file->f_pos;
  		break;
  	case SEEK_DATA:
  	case SEEK_HOLE:
  		ret = ocfs2_seek_data_hole_offset(file, &offset, origin);
  		if (ret)
  			goto out;
  		break;
  	default:
  		ret = -EINVAL;
  		goto out;
  	}
  
  	if (offset < 0 && !(file->f_mode & FMODE_UNSIGNED_OFFSET))
  		ret = -EINVAL;
  	if (!ret && offset > inode->i_sb->s_maxbytes)
  		ret = -EINVAL;
  	if (ret)
  		goto out;
  
  	if (offset != file->f_pos) {
  		file->f_pos = offset;
  		file->f_version = 0;
  	}
  
  out:
  	mutex_unlock(&inode->i_mutex);
  	if (ret)
  		return ret;
  	return offset;
  }
  
  const struct inode_operations ocfs2_file_iops = {
  	.setattr	= ocfs2_setattr,
  	.getattr	= ocfs2_getattr,
  	.permission	= ocfs2_permission,
  	.setxattr	= generic_setxattr,
  	.getxattr	= generic_getxattr,
  	.listxattr	= ocfs2_listxattr,
  	.removexattr	= generic_removexattr,
  	.fiemap		= ocfs2_fiemap,
  	.get_acl	= ocfs2_iop_get_acl,
  };
  
  const struct inode_operations ocfs2_special_file_iops = {
  	.setattr	= ocfs2_setattr,
  	.getattr	= ocfs2_getattr,
  	.permission	= ocfs2_permission,
  	.get_acl	= ocfs2_iop_get_acl,
  };
  
  /*
   * Other than ->lock, keep ocfs2_fops and ocfs2_dops in sync with
   * ocfs2_fops_no_plocks and ocfs2_dops_no_plocks!
   */
  const struct file_operations ocfs2_fops = {
  	.llseek		= ocfs2_file_llseek,
  	.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,
  	.unlocked_ioctl	= ocfs2_ioctl,
  #ifdef CONFIG_COMPAT
  	.compat_ioctl   = ocfs2_compat_ioctl,
  #endif
  	.lock		= ocfs2_lock,
  	.flock		= ocfs2_flock,
  	.splice_read	= ocfs2_file_splice_read,
  	.splice_write	= ocfs2_file_splice_write,
  	.fallocate	= ocfs2_fallocate,
  };
  
  const struct file_operations ocfs2_dops = {
  	.llseek		= generic_file_llseek,
  	.read		= generic_read_dir,
  	.readdir	= ocfs2_readdir,
  	.fsync		= ocfs2_sync_file,
  	.release	= ocfs2_dir_release,
  	.open		= ocfs2_dir_open,
  	.unlocked_ioctl	= ocfs2_ioctl,
  #ifdef CONFIG_COMPAT
  	.compat_ioctl   = ocfs2_compat_ioctl,
  #endif
  	.lock		= ocfs2_lock,
  	.flock		= ocfs2_flock,
  };
  
  /*
   * POSIX-lockless variants of our file_operations.
   *
   * These will be used if the underlying cluster stack does not support
   * posix file locking, if the user passes the "localflocks" mount
   * option, or if we have a local-only fs.
   *
   * ocfs2_flock is in here because all stacks handle UNIX file locks,
   * so we still want it in the case of no stack support for
   * plocks. Internally, it will do the right thing when asked to ignore
   * the cluster.
   */
  const struct file_operations ocfs2_fops_no_plocks = {
  	.llseek		= ocfs2_file_llseek,
  	.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,
  	.unlocked_ioctl	= ocfs2_ioctl,
  #ifdef CONFIG_COMPAT
  	.compat_ioctl   = ocfs2_compat_ioctl,
  #endif
  	.flock		= ocfs2_flock,
  	.splice_read	= ocfs2_file_splice_read,
  	.splice_write	= ocfs2_file_splice_write,
  	.fallocate	= ocfs2_fallocate,
  };
  
  const struct file_operations ocfs2_dops_no_plocks = {
  	.llseek		= generic_file_llseek,
  	.read		= generic_read_dir,
  	.readdir	= ocfs2_readdir,
  	.fsync		= ocfs2_sync_file,
  	.release	= ocfs2_dir_release,
  	.open		= ocfs2_dir_open,
  	.unlocked_ioctl	= ocfs2_ioctl,
  #ifdef CONFIG_COMPAT
  	.compat_ioctl   = ocfs2_compat_ioctl,
  #endif
  	.flock		= ocfs2_flock,
  };
  