[PATCH 18.1/35] Btrfs inode operations

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The basic inode and directory inode operations live here.

Signed-off-by: Chris Mason <chris.mason@xxxxxxxxxx>

--- /dev/null	2008-06-10 15:56:50.000000000 -0400
+++ b/fs/btrfs/inode.c	2009-01-08 09:43:29.596585385 -0500
@@ -0,0 +1,2907 @@
+/*
+ * Copyright (C) 2007 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 v2 as published by the Free Software Foundation.
+ *
+ * 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/kernel.h>
+#include <linux/bio.h>
+#include <linux/buffer_head.h>
+#include <linux/file.h>
+#include <linux/fs.h>
+#include <linux/pagemap.h>
+#include <linux/highmem.h>
+#include <linux/time.h>
+#include <linux/init.h>
+#include <linux/string.h>
+#include <linux/smp_lock.h>
+#include <linux/backing-dev.h>
+#include <linux/mpage.h>
+#include <linux/swap.h>
+#include <linux/writeback.h>
+#include <linux/statfs.h>
+#include <linux/compat.h>
+#include <linux/bit_spinlock.h>
+#include <linux/version.h>
+#include <linux/xattr.h>
+#include <linux/posix_acl.h>
+#include <linux/falloc.h>
+#include "compat.h"
+#include "ctree.h"
+#include "disk-io.h"
+#include "transaction.h"
+#include "btrfs_inode.h"
+#include "ioctl.h"
+#include "print-tree.h"
+#include "volumes.h"
+#include "ordered-data.h"
+#include "xattr.h"
+#include "tree-log.h"
+#include "ref-cache.h"
+#include "compression.h"
+
+struct btrfs_iget_args {
+	u64 ino;
+	struct btrfs_root *root;
+};
+
+static struct inode_operations btrfs_dir_inode_operations;
+static struct inode_operations btrfs_symlink_inode_operations;
+static struct inode_operations btrfs_dir_ro_inode_operations;
+static struct inode_operations btrfs_special_inode_operations;
+static struct inode_operations btrfs_file_inode_operations;
+static struct address_space_operations btrfs_aops;
+static struct address_space_operations btrfs_symlink_aops;
+static struct file_operations btrfs_dir_file_operations;
+static struct extent_io_ops btrfs_extent_io_ops;
+
+static struct kmem_cache *btrfs_inode_cachep;
+struct kmem_cache *btrfs_trans_handle_cachep;
+struct kmem_cache *btrfs_transaction_cachep;
+struct kmem_cache *btrfs_bit_radix_cachep;
+struct kmem_cache *btrfs_path_cachep;
+
+#define S_SHIFT 12
+static unsigned char btrfs_type_by_mode[S_IFMT >> S_SHIFT] = {
+	[S_IFREG >> S_SHIFT]	= BTRFS_FT_REG_FILE,
+	[S_IFDIR >> S_SHIFT]	= BTRFS_FT_DIR,
+	[S_IFCHR >> S_SHIFT]	= BTRFS_FT_CHRDEV,
+	[S_IFBLK >> S_SHIFT]	= BTRFS_FT_BLKDEV,
+	[S_IFIFO >> S_SHIFT]	= BTRFS_FT_FIFO,
+	[S_IFSOCK >> S_SHIFT]	= BTRFS_FT_SOCK,
+	[S_IFLNK >> S_SHIFT]	= BTRFS_FT_SYMLINK,
+};
+
+static void btrfs_truncate(struct inode *inode);
+static noinline int cow_file_range(struct inode *inode,
+				   struct page *locked_page,
+				   u64 start, u64 end, int *page_started,
+				   unsigned long *nr_written, int unlock);
+
+/*
+ * a very lame attempt at stopping writes when the FS is 85% full.  There
+ * are countless ways this is incorrect, but it is better than nothing.
+ */
+int btrfs_check_free_space(struct btrfs_root *root, u64 num_required,
+			   int for_del)
+{
+	u64 total;
+	u64 used;
+	u64 thresh;
+	int ret = 0;
+
+	spin_lock(&root->fs_info->delalloc_lock);
+	total = btrfs_super_total_bytes(&root->fs_info->super_copy);
+	used = btrfs_super_bytes_used(&root->fs_info->super_copy);
+	if (for_del)
+		thresh = total * 90;
+	else
+		thresh = total * 85;
+
+	do_div(thresh, 100);
+
+	if (used + root->fs_info->delalloc_bytes + num_required > thresh)
+		ret = -ENOSPC;
+	spin_unlock(&root->fs_info->delalloc_lock);
+	return ret;
+}
+
+static int insert_reserved_file_extent(struct btrfs_trans_handle *trans,
+				       struct inode *inode, u64 file_pos,
+				       u64 disk_bytenr, u64 disk_num_bytes,
+				       u64 num_bytes, u64 ram_bytes,
+				       u8 compression, u8 encryption,
+				       u16 other_encoding, int extent_type)
+{
+	struct btrfs_root *root = BTRFS_I(inode)->root;
+	struct btrfs_file_extent_item *fi;
+	struct btrfs_path *path;
+	struct extent_buffer *leaf;
+	struct btrfs_key ins;
+	u64 hint;
+	int ret;
+
+	path = btrfs_alloc_path();
+	BUG_ON(!path);
+
+	ret = btrfs_drop_extents(trans, root, inode, file_pos,
+				 file_pos + num_bytes, file_pos, &hint);
+	BUG_ON(ret);
+
+	ins.objectid = inode->i_ino;
+	ins.offset = file_pos;
+	ins.type = BTRFS_EXTENT_DATA_KEY;
+	ret = btrfs_insert_empty_item(trans, root, path, &ins, sizeof(*fi));
+	BUG_ON(ret);
+	leaf = path->nodes[0];
+	fi = btrfs_item_ptr(leaf, path->slots[0],
+			    struct btrfs_file_extent_item);
+	btrfs_set_file_extent_generation(leaf, fi, trans->transid);
+	btrfs_set_file_extent_type(leaf, fi, extent_type);
+	btrfs_set_file_extent_disk_bytenr(leaf, fi, disk_bytenr);
+	btrfs_set_file_extent_disk_num_bytes(leaf, fi, disk_num_bytes);
+	btrfs_set_file_extent_offset(leaf, fi, 0);
+	btrfs_set_file_extent_num_bytes(leaf, fi, num_bytes);
+	btrfs_set_file_extent_ram_bytes(leaf, fi, ram_bytes);
+	btrfs_set_file_extent_compression(leaf, fi, compression);
+	btrfs_set_file_extent_encryption(leaf, fi, encryption);
+	btrfs_set_file_extent_other_encoding(leaf, fi, other_encoding);
+	btrfs_mark_buffer_dirty(leaf);
+
+	inode_add_bytes(inode, num_bytes);
+	btrfs_drop_extent_cache(inode, file_pos, file_pos + num_bytes - 1, 0);
+
+	ins.objectid = disk_bytenr;
+	ins.offset = disk_num_bytes;
+	ins.type = BTRFS_EXTENT_ITEM_KEY;
+	ret = btrfs_alloc_reserved_extent(trans, root, leaf->start,
+					  root->root_key.objectid,
+					  trans->transid, inode->i_ino, &ins);
+	BUG_ON(ret);
+
+	btrfs_free_path(path);
+	return 0;
+}
+
+/*
+ * This creates an orphan entry for the given inode in case something goes
+ * wrong in the middle of an unlink/truncate.
+ */
+int btrfs_orphan_add(struct btrfs_trans_handle *trans, struct inode *inode)
+{
+	struct btrfs_root *root = BTRFS_I(inode)->root;
+	int ret = 0;
+
+	spin_lock(&root->list_lock);
+
+	/* already on the orphan list, we're good */
+	if (!list_empty(&BTRFS_I(inode)->i_orphan)) {
+		spin_unlock(&root->list_lock);
+		return 0;
+	}
+
+	list_add(&BTRFS_I(inode)->i_orphan, &root->orphan_list);
+
+	spin_unlock(&root->list_lock);
+
+	/*
+	 * insert an orphan item to track this unlinked/truncated file
+	 */
+	ret = btrfs_insert_orphan_item(trans, root, inode->i_ino);
+
+	return ret;
+}
+
+/*
+ * We have done the truncate/delete so we can go ahead and remove the orphan
+ * item for this particular inode.
+ */
+int btrfs_orphan_del(struct btrfs_trans_handle *trans, struct inode *inode)
+{
+	struct btrfs_root *root = BTRFS_I(inode)->root;
+	int ret = 0;
+
+	spin_lock(&root->list_lock);
+
+	if (list_empty(&BTRFS_I(inode)->i_orphan)) {
+		spin_unlock(&root->list_lock);
+		return 0;
+	}
+
+	list_del_init(&BTRFS_I(inode)->i_orphan);
+	if (!trans) {
+		spin_unlock(&root->list_lock);
+		return 0;
+	}
+
+	spin_unlock(&root->list_lock);
+
+	ret = btrfs_del_orphan_item(trans, root, inode->i_ino);
+
+	return ret;
+}
+
+/*
+ * this cleans up any orphans that may be left on the list from the last use
+ * of this root.
+ */
+void btrfs_orphan_cleanup(struct btrfs_root *root)
+{
+	struct btrfs_path *path;
+	struct extent_buffer *leaf;
+	struct btrfs_item *item;
+	struct btrfs_key key, found_key;
+	struct btrfs_trans_handle *trans;
+	struct inode *inode;
+	int ret = 0, nr_unlink = 0, nr_truncate = 0;
+
+	path = btrfs_alloc_path();
+	if (!path)
+		return;
+	path->reada = -1;
+
+	key.objectid = BTRFS_ORPHAN_OBJECTID;
+	btrfs_set_key_type(&key, BTRFS_ORPHAN_ITEM_KEY);
+	key.offset = (u64)-1;
+
+
+	while (1) {
+		ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
+		if (ret < 0) {
+			printk(KERN_ERR "Error searching slot for orphan: %d"
+			       "\n", ret);
+			break;
+		}
+
+		/*
+		 * if ret == 0 means we found what we were searching for, which
+		 * is weird, but possible, so only screw with path if we didnt
+		 * find the key and see if we have stuff that matches
+		 */
+		if (ret > 0) {
+			if (path->slots[0] == 0)
+				break;
+			path->slots[0]--;
+		}
+
+		/* pull out the item */
+		leaf = path->nodes[0];
+		item = btrfs_item_nr(leaf, path->slots[0]);
+		btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
+
+		/* make sure the item matches what we want */
+		if (found_key.objectid != BTRFS_ORPHAN_OBJECTID)
+			break;
+		if (btrfs_key_type(&found_key) != BTRFS_ORPHAN_ITEM_KEY)
+			break;
+
+		/* release the path since we're done with it */
+		btrfs_release_path(root, path);
+
+		/*
+		 * this is where we are basically btrfs_lookup, without the
+		 * crossing root thing.  we store the inode number in the
+		 * offset of the orphan item.
+		 */
+		inode = btrfs_iget_locked(root->fs_info->sb,
+					  found_key.offset, root);
+		if (!inode)
+			break;
+
+		if (inode->i_state & I_NEW) {
+			BTRFS_I(inode)->root = root;
+
+			/* have to set the location manually */
+			BTRFS_I(inode)->location.objectid = inode->i_ino;
+			BTRFS_I(inode)->location.type = BTRFS_INODE_ITEM_KEY;
+			BTRFS_I(inode)->location.offset = 0;
+
+			btrfs_read_locked_inode(inode);
+			unlock_new_inode(inode);
+		}
+
+		/*
+		 * add this inode to the orphan list so btrfs_orphan_del does
+		 * the proper thing when we hit it
+		 */
+		spin_lock(&root->list_lock);
+		list_add(&BTRFS_I(inode)->i_orphan, &root->orphan_list);
+		spin_unlock(&root->list_lock);
+
+		/*
+		 * if this is a bad inode, means we actually succeeded in
+		 * removing the inode, but not the orphan record, which means
+		 * we need to manually delete the orphan since iput will just
+		 * do a destroy_inode
+		 */
+		if (is_bad_inode(inode)) {
+			trans = btrfs_start_transaction(root, 1);
+			btrfs_orphan_del(trans, inode);
+			btrfs_end_transaction(trans, root);
+			iput(inode);
+			continue;
+		}
+
+		/* if we have links, this was a truncate, lets do that */
+		if (inode->i_nlink) {
+			nr_truncate++;
+			btrfs_truncate(inode);
+		} else {
+			nr_unlink++;
+		}
+
+		/* this will do delete_inode and everything for us */
+		iput(inode);
+	}
+
+	if (nr_unlink)
+		printk(KERN_INFO "btrfs: unlinked %d orphans\n", nr_unlink);
+	if (nr_truncate)
+		printk(KERN_INFO "btrfs: truncated %d orphans\n", nr_truncate);
+
+	btrfs_free_path(path);
+}
+
+/*
+ * read an inode from the btree into the in-memory inode
+ */
+void btrfs_read_locked_inode(struct inode *inode)
+{
+	struct btrfs_path *path;
+	struct extent_buffer *leaf;
+	struct btrfs_inode_item *inode_item;
+	struct btrfs_timespec *tspec;
+	struct btrfs_root *root = BTRFS_I(inode)->root;
+	struct btrfs_key location;
+	u64 alloc_group_block;
+	u32 rdev;
+	int ret;
+
+	path = btrfs_alloc_path();
+	BUG_ON(!path);
+	memcpy(&location, &BTRFS_I(inode)->location, sizeof(location));
+
+	ret = btrfs_lookup_inode(NULL, root, path, &location, 0);
+	if (ret)
+		goto make_bad;
+
+	leaf = path->nodes[0];
+	inode_item = btrfs_item_ptr(leaf, path->slots[0],
+				    struct btrfs_inode_item);
+
+	inode->i_mode = btrfs_inode_mode(leaf, inode_item);
+	inode->i_nlink = btrfs_inode_nlink(leaf, inode_item);
+	inode->i_uid = btrfs_inode_uid(leaf, inode_item);
+	inode->i_gid = btrfs_inode_gid(leaf, inode_item);
+	btrfs_i_size_write(inode, btrfs_inode_size(leaf, inode_item));
+
+	tspec = btrfs_inode_atime(inode_item);
+	inode->i_atime.tv_sec = btrfs_timespec_sec(leaf, tspec);
+	inode->i_atime.tv_nsec = btrfs_timespec_nsec(leaf, tspec);
+
+	tspec = btrfs_inode_mtime(inode_item);
+	inode->i_mtime.tv_sec = btrfs_timespec_sec(leaf, tspec);
+	inode->i_mtime.tv_nsec = btrfs_timespec_nsec(leaf, tspec);
+
+	tspec = btrfs_inode_ctime(inode_item);
+	inode->i_ctime.tv_sec = btrfs_timespec_sec(leaf, tspec);
+	inode->i_ctime.tv_nsec = btrfs_timespec_nsec(leaf, tspec);
+
+	inode_set_bytes(inode, btrfs_inode_nbytes(leaf, inode_item));
+	BTRFS_I(inode)->generation = btrfs_inode_generation(leaf, inode_item);
+	BTRFS_I(inode)->sequence = btrfs_inode_sequence(leaf, inode_item);
+	inode->i_generation = BTRFS_I(inode)->generation;
+	inode->i_rdev = 0;
+	rdev = btrfs_inode_rdev(leaf, inode_item);
+
+	BTRFS_I(inode)->index_cnt = (u64)-1;
+	BTRFS_I(inode)->flags = btrfs_inode_flags(leaf, inode_item);
+
+	alloc_group_block = btrfs_inode_block_group(leaf, inode_item);
+	BTRFS_I(inode)->block_group = btrfs_find_block_group(root, 0,
+						alloc_group_block, 0);
+	btrfs_free_path(path);
+	inode_item = NULL;
+
+	switch (inode->i_mode & S_IFMT) {
+	case S_IFREG:
+		inode->i_mapping->a_ops = &btrfs_aops;
+		inode->i_mapping->backing_dev_info = &root->fs_info->bdi;
+		BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
+		inode->i_fop = &btrfs_file_operations;
+		inode->i_op = &btrfs_file_inode_operations;
+		break;
+	case S_IFDIR:
+		inode->i_fop = &btrfs_dir_file_operations;
+		if (root == root->fs_info->tree_root)
+			inode->i_op = &btrfs_dir_ro_inode_operations;
+		else
+			inode->i_op = &btrfs_dir_inode_operations;
+		break;
+	case S_IFLNK:
+		inode->i_op = &btrfs_symlink_inode_operations;
+		inode->i_mapping->a_ops = &btrfs_symlink_aops;
+		inode->i_mapping->backing_dev_info = &root->fs_info->bdi;
+		break;
+	default:
+		init_special_inode(inode, inode->i_mode, rdev);
+		break;
+	}
+	return;
+
+make_bad:
+	btrfs_free_path(path);
+	make_bad_inode(inode);
+}
+
+/*
+ * given a leaf and an inode, copy the inode fields into the leaf
+ */
+static void fill_inode_item(struct btrfs_trans_handle *trans,
+			    struct extent_buffer *leaf,
+			    struct btrfs_inode_item *item,
+			    struct inode *inode)
+{
+	btrfs_set_inode_uid(leaf, item, inode->i_uid);
+	btrfs_set_inode_gid(leaf, item, inode->i_gid);
+	btrfs_set_inode_size(leaf, item, BTRFS_I(inode)->disk_i_size);
+	btrfs_set_inode_mode(leaf, item, inode->i_mode);
+	btrfs_set_inode_nlink(leaf, item, inode->i_nlink);
+
+	btrfs_set_timespec_sec(leaf, btrfs_inode_atime(item),
+			       inode->i_atime.tv_sec);
+	btrfs_set_timespec_nsec(leaf, btrfs_inode_atime(item),
+				inode->i_atime.tv_nsec);
+
+	btrfs_set_timespec_sec(leaf, btrfs_inode_mtime(item),
+			       inode->i_mtime.tv_sec);
+	btrfs_set_timespec_nsec(leaf, btrfs_inode_mtime(item),
+				inode->i_mtime.tv_nsec);
+
+	btrfs_set_timespec_sec(leaf, btrfs_inode_ctime(item),
+			       inode->i_ctime.tv_sec);
+	btrfs_set_timespec_nsec(leaf, btrfs_inode_ctime(item),
+				inode->i_ctime.tv_nsec);
+
+	btrfs_set_inode_nbytes(leaf, item, inode_get_bytes(inode));
+	btrfs_set_inode_generation(leaf, item, BTRFS_I(inode)->generation);
+	btrfs_set_inode_sequence(leaf, item, BTRFS_I(inode)->sequence);
+	btrfs_set_inode_transid(leaf, item, trans->transid);
+	btrfs_set_inode_rdev(leaf, item, inode->i_rdev);
+	btrfs_set_inode_flags(leaf, item, BTRFS_I(inode)->flags);
+	btrfs_set_inode_block_group(leaf, item, BTRFS_I(inode)->block_group);
+}
+
+/*
+ * copy everything in the in-memory inode into the btree.
+ */
+noinline int btrfs_update_inode(struct btrfs_trans_handle *trans,
+				struct btrfs_root *root, struct inode *inode)
+{
+	struct btrfs_inode_item *inode_item;
+	struct btrfs_path *path;
+	struct extent_buffer *leaf;
+	int ret;
+
+	path = btrfs_alloc_path();
+	BUG_ON(!path);
+	ret = btrfs_lookup_inode(trans, root, path,
+				 &BTRFS_I(inode)->location, 1);
+	if (ret) {
+		if (ret > 0)
+			ret = -ENOENT;
+		goto failed;
+	}
+
+	leaf = path->nodes[0];
+	inode_item = btrfs_item_ptr(leaf, path->slots[0],
+				  struct btrfs_inode_item);
+
+	fill_inode_item(trans, leaf, inode_item, inode);
+	btrfs_mark_buffer_dirty(leaf);
+	btrfs_set_inode_last_trans(trans, inode);
+	ret = 0;
+failed:
+	btrfs_free_path(path);
+	return ret;
+}
+
+
+/*
+ * unlink helper that gets used here in inode.c and in the tree logging
+ * recovery code.  It remove a link in a directory with a given name, and
+ * also drops the back refs in the inode to the directory
+ */
+int btrfs_unlink_inode(struct btrfs_trans_handle *trans,
+		       struct btrfs_root *root,
+		       struct inode *dir, struct inode *inode,
+		       const char *name, int name_len)
+{
+	struct btrfs_path *path;
+	int ret = 0;
+	struct extent_buffer *leaf;
+	struct btrfs_dir_item *di;
+	struct btrfs_key key;
+	u64 index;
+
+	path = btrfs_alloc_path();
+	if (!path) {
+		ret = -ENOMEM;
+		goto err;
+	}
+
+	di = btrfs_lookup_dir_item(trans, root, path, dir->i_ino,
+				    name, name_len, -1);
+	if (IS_ERR(di)) {
+		ret = PTR_ERR(di);
+		goto err;
+	}
+	if (!di) {
+		ret = -ENOENT;
+		goto err;
+	}
+	leaf = path->nodes[0];
+	btrfs_dir_item_key_to_cpu(leaf, di, &key);
+	ret = btrfs_delete_one_dir_name(trans, root, path, di);
+	if (ret)
+		goto err;
+	btrfs_release_path(root, path);
+
+	ret = btrfs_del_inode_ref(trans, root, name, name_len,
+				  inode->i_ino,
+				  dir->i_ino, &index);
+	if (ret) {
+		printk(KERN_INFO "btrfs failed to delete reference to %.*s, "
+		       "inode %lu parent %lu\n", name_len, name,
+		       inode->i_ino, dir->i_ino);
+		goto err;
+	}
+
+	di = btrfs_lookup_dir_index_item(trans, root, path, dir->i_ino,
+					 index, name, name_len, -1);
+	if (IS_ERR(di)) {
+		ret = PTR_ERR(di);
+		goto err;
+	}
+	if (!di) {
+		ret = -ENOENT;
+		goto err;
+	}
+	ret = btrfs_delete_one_dir_name(trans, root, path, di);
+	btrfs_release_path(root, path);
+
+	ret = btrfs_del_inode_ref_in_log(trans, root, name, name_len,
+					 inode, dir->i_ino);
+	BUG_ON(ret != 0 && ret != -ENOENT);
+	if (ret != -ENOENT)
+		BTRFS_I(dir)->log_dirty_trans = trans->transid;
+
+	ret = btrfs_del_dir_entries_in_log(trans, root, name, name_len,
+					   dir, index);
+	BUG_ON(ret);
+err:
+	btrfs_free_path(path);
+	if (ret)
+		goto out;
+
+	btrfs_i_size_write(dir, dir->i_size - name_len * 2);
+	inode->i_ctime = dir->i_mtime = dir->i_ctime = CURRENT_TIME;
+	btrfs_update_inode(trans, root, dir);
+	btrfs_drop_nlink(inode);
+	ret = btrfs_update_inode(trans, root, inode);
+	dir->i_sb->s_dirt = 1;
+out:
+	return ret;
+}
+
+static int btrfs_unlink(struct inode *dir, struct dentry *dentry)
+{
+	struct btrfs_root *root;
+	struct btrfs_trans_handle *trans;
+	struct inode *inode = dentry->d_inode;
+	int ret;
+	unsigned long nr = 0;
+
+	root = BTRFS_I(dir)->root;
+
+	ret = btrfs_check_free_space(root, 1, 1);
+	if (ret)
+		goto fail;
+
+	trans = btrfs_start_transaction(root, 1);
+
+	btrfs_set_trans_block_group(trans, dir);
+	ret = btrfs_unlink_inode(trans, root, dir, dentry->d_inode,
+				 dentry->d_name.name, dentry->d_name.len);
+
+	if (inode->i_nlink == 0)
+		ret = btrfs_orphan_add(trans, inode);
+
+	nr = trans->blocks_used;
+
+	btrfs_end_transaction_throttle(trans, root);
+fail:
+	btrfs_btree_balance_dirty(root, nr);
+	return ret;
+}
+
+static int btrfs_rmdir(struct inode *dir, struct dentry *dentry)
+{
+	struct inode *inode = dentry->d_inode;
+	int err = 0;
+	int ret;
+	struct btrfs_root *root = BTRFS_I(dir)->root;
+	struct btrfs_trans_handle *trans;
+	unsigned long nr = 0;
+
+	/*
+	 * the FIRST_FREE_OBJECTID check makes sure we don't try to rmdir
+	 * the root of a subvolume or snapshot
+	 */
+	if (inode->i_size > BTRFS_EMPTY_DIR_SIZE ||
+	    inode->i_ino == BTRFS_FIRST_FREE_OBJECTID) {
+		return -ENOTEMPTY;
+	}
+
+	ret = btrfs_check_free_space(root, 1, 1);
+	if (ret)
+		goto fail;
+
+	trans = btrfs_start_transaction(root, 1);
+	btrfs_set_trans_block_group(trans, dir);
+
+	err = btrfs_orphan_add(trans, inode);
+	if (err)
+		goto fail_trans;
+
+	/* now the directory is empty */
+	err = btrfs_unlink_inode(trans, root, dir, dentry->d_inode,
+				 dentry->d_name.name, dentry->d_name.len);
+	if (!err)
+		btrfs_i_size_write(inode, 0);
+
+fail_trans:
+	nr = trans->blocks_used;
+	ret = btrfs_end_transaction_throttle(trans, root);
+fail:
+	btrfs_btree_balance_dirty(root, nr);
+
+	if (ret && !err)
+		err = ret;
+	return err;
+}
+
+/*
+ * this can truncate away extent items, csum items and directory items.
+ * It starts at a high offset and removes keys until it can't find
+ * any higher than new_size
+ *
+ * csum items that cross the new i_size are truncated to the new size
+ * as well.
+ *
+ * min_type is the minimum key type to truncate down to.  If set to 0, this
+ * will kill all the items on this inode, including the INODE_ITEM_KEY.
+ */
+noinline int btrfs_truncate_inode_items(struct btrfs_trans_handle *trans,
+					struct btrfs_root *root,
+					struct inode *inode,
+					u64 new_size, u32 min_type)
+{
+	int ret;
+	struct btrfs_path *path;
+	struct btrfs_key key;
+	struct btrfs_key found_key;
+	u32 found_type;
+	struct extent_buffer *leaf;
+	struct btrfs_file_extent_item *fi;
+	u64 extent_start = 0;
+	u64 extent_num_bytes = 0;
+	u64 item_end = 0;
+	u64 root_gen = 0;
+	u64 root_owner = 0;
+	int found_extent;
+	int del_item;
+	int pending_del_nr = 0;
+	int pending_del_slot = 0;
+	int extent_type = -1;
+	int encoding;
+	u64 mask = root->sectorsize - 1;
+
+	if (root->ref_cows)
+		btrfs_drop_extent_cache(inode, new_size & (~mask), (u64)-1, 0);
+	path = btrfs_alloc_path();
+	path->reada = -1;
+	BUG_ON(!path);
+
+	/* FIXME, add redo link to tree so we don't leak on crash */
+	key.objectid = inode->i_ino;
+	key.offset = (u64)-1;
+	key.type = (u8)-1;
+
+	btrfs_init_path(path);
+
+search_again:
+	ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
+	if (ret < 0)
+		goto error;
+
+	if (ret > 0) {
+		/* there are no items in the tree for us to truncate, we're
+		 * done
+		 */
+		if (path->slots[0] == 0) {
+			ret = 0;
+			goto error;
+		}
+		path->slots[0]--;
+	}
+
+	while (1) {
+		fi = NULL;
+		leaf = path->nodes[0];
+		btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
+		found_type = btrfs_key_type(&found_key);
+		encoding = 0;
+
+		if (found_key.objectid != inode->i_ino)
+			break;
+
+		if (found_type < min_type)
+			break;
+
+		item_end = found_key.offset;
+		if (found_type == BTRFS_EXTENT_DATA_KEY) {
+			fi = btrfs_item_ptr(leaf, path->slots[0],
+					    struct btrfs_file_extent_item);
+			extent_type = btrfs_file_extent_type(leaf, fi);
+			encoding = btrfs_file_extent_compression(leaf, fi);
+			encoding |= btrfs_file_extent_encryption(leaf, fi);
+			encoding |= btrfs_file_extent_other_encoding(leaf, fi);
+
+			if (extent_type != BTRFS_FILE_EXTENT_INLINE) {
+				item_end +=
+				    btrfs_file_extent_num_bytes(leaf, fi);
+			} else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
+				item_end += btrfs_file_extent_inline_len(leaf,
+									 fi);
+			}
+			item_end--;
+		}
+		if (item_end < new_size) {
+			if (found_type == BTRFS_DIR_ITEM_KEY)
+				found_type = BTRFS_INODE_ITEM_KEY;
+			else if (found_type == BTRFS_EXTENT_ITEM_KEY)
+				found_type = BTRFS_EXTENT_DATA_KEY;
+			else if (found_type == BTRFS_EXTENT_DATA_KEY)
+				found_type = BTRFS_XATTR_ITEM_KEY;
+			else if (found_type == BTRFS_XATTR_ITEM_KEY)
+				found_type = BTRFS_INODE_REF_KEY;
+			else if (found_type)
+				found_type--;
+			else
+				break;
+			btrfs_set_key_type(&key, found_type);
+			goto next;
+		}
+		if (found_key.offset >= new_size)
+			del_item = 1;
+		else
+			del_item = 0;
+		found_extent = 0;
+
+		/* FIXME, shrink the extent if the ref count is only 1 */
+		if (found_type != BTRFS_EXTENT_DATA_KEY)
+			goto delete;
+
+		if (extent_type != BTRFS_FILE_EXTENT_INLINE) {
+			u64 num_dec;
+			extent_start = btrfs_file_extent_disk_bytenr(leaf, fi);
+			if (!del_item && !encoding) {
+				u64 orig_num_bytes =
+					btrfs_file_extent_num_bytes(leaf, fi);
+				extent_num_bytes = new_size -
+					found_key.offset + root->sectorsize - 1;
+				extent_num_bytes = extent_num_bytes &
+					~((u64)root->sectorsize - 1);
+				btrfs_set_file_extent_num_bytes(leaf, fi,
+							 extent_num_bytes);
+				num_dec = (orig_num_bytes -
+					   extent_num_bytes);
+				if (root->ref_cows && extent_start != 0)
+					inode_sub_bytes(inode, num_dec);
+				btrfs_mark_buffer_dirty(leaf);
+			} else {
+				extent_num_bytes =
+					btrfs_file_extent_disk_num_bytes(leaf,
+									 fi);
+				/* FIXME blocksize != 4096 */
+				num_dec = btrfs_file_extent_num_bytes(leaf, fi);
+				if (extent_start != 0) {
+					found_extent = 1;
+					if (root->ref_cows)
+						inode_sub_bytes(inode, num_dec);
+				}
+				root_gen = btrfs_header_generation(leaf);
+				root_owner = btrfs_header_owner(leaf);
+			}
+		} else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
+			/*
+			 * we can't truncate inline items that have had
+			 * special encodings
+			 */
+			if (!del_item &&
+			    btrfs_file_extent_compression(leaf, fi) == 0 &&
+			    btrfs_file_extent_encryption(leaf, fi) == 0 &&
+			    btrfs_file_extent_other_encoding(leaf, fi) == 0) {
+				u32 size = new_size - found_key.offset;
+
+				if (root->ref_cows) {
+					inode_sub_bytes(inode, item_end + 1 -
+							new_size);
+				}
+				size =
+				    btrfs_file_extent_calc_inline_size(size);
+				ret = btrfs_truncate_item(trans, root, path,
+							  size, 1);
+				BUG_ON(ret);
+			} else if (root->ref_cows) {
+				inode_sub_bytes(inode, item_end + 1 -
+						found_key.offset);
+			}
+		}
+delete:
+		if (del_item) {
+			if (!pending_del_nr) {
+				/* no pending yet, add ourselves */
+				pending_del_slot = path->slots[0];
+				pending_del_nr = 1;
+			} else if (pending_del_nr &&
+				   path->slots[0] + 1 == pending_del_slot) {
+				/* hop on the pending chunk */
+				pending_del_nr++;
+				pending_del_slot = path->slots[0];
+			} else {
+				BUG();
+			}
+		} else {
+			break;
+		}
+		if (found_extent) {
+			ret = btrfs_free_extent(trans, root, extent_start,
+						extent_num_bytes,
+						leaf->start, root_owner,
+						root_gen, inode->i_ino, 0);
+			BUG_ON(ret);
+		}
+next:
+		if (path->slots[0] == 0) {
+			if (pending_del_nr)
+				goto del_pending;
+			btrfs_release_path(root, path);
+			goto search_again;
+		}
+
+		path->slots[0]--;
+		if (pending_del_nr &&
+		    path->slots[0] + 1 != pending_del_slot) {
+			struct btrfs_key debug;
+del_pending:
+			btrfs_item_key_to_cpu(path->nodes[0], &debug,
+					      pending_del_slot);
+			ret = btrfs_del_items(trans, root, path,
+					      pending_del_slot,
+					      pending_del_nr);
+			BUG_ON(ret);
+			pending_del_nr = 0;
+			btrfs_release_path(root, path);
+			goto search_again;
+		}
+	}
+	ret = 0;
+error:
+	if (pending_del_nr) {
+		ret = btrfs_del_items(trans, root, path, pending_del_slot,
+				      pending_del_nr);
+	}
+	btrfs_free_path(path);
+	inode->i_sb->s_dirt = 1;
+	return ret;
+}
+
+/*
+ * taken from block_truncate_page, but does cow as it zeros out
+ * any bytes left in the last page in the file.
+ */
+static int btrfs_truncate_page(struct address_space *mapping, loff_t from)
+{
+	struct inode *inode = mapping->host;
+	struct btrfs_root *root = BTRFS_I(inode)->root;
+	struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
+	struct btrfs_ordered_extent *ordered;
+	char *kaddr;
+	u32 blocksize = root->sectorsize;
+	pgoff_t index = from >> PAGE_CACHE_SHIFT;
+	unsigned offset = from & (PAGE_CACHE_SIZE-1);
+	struct page *page;
+	int ret = 0;
+	u64 page_start;
+	u64 page_end;
+
+	if ((offset & (blocksize - 1)) == 0)
+		goto out;
+
+	ret = -ENOMEM;
+again:
+	page = grab_cache_page(mapping, index);
+	if (!page)
+		goto out;
+
+	page_start = page_offset(page);
+	page_end = page_start + PAGE_CACHE_SIZE - 1;
+
+	if (!PageUptodate(page)) {
+		ret = btrfs_readpage(NULL, page);
+		lock_page(page);
+		if (page->mapping != mapping) {
+			unlock_page(page);
+			page_cache_release(page);
+			goto again;
+		}
+		if (!PageUptodate(page)) {
+			ret = -EIO;
+			goto out_unlock;
+		}
+	}
+	wait_on_page_writeback(page);
+
+	lock_extent(io_tree, page_start, page_end, GFP_NOFS);
+	set_page_extent_mapped(page);
+
+	ordered = btrfs_lookup_ordered_extent(inode, page_start);
+	if (ordered) {
+		unlock_extent(io_tree, page_start, page_end, GFP_NOFS);
+		unlock_page(page);
+		page_cache_release(page);
+		btrfs_start_ordered_extent(inode, ordered, 1);
+		btrfs_put_ordered_extent(ordered);
+		goto again;
+	}
+
+	btrfs_set_extent_delalloc(inode, page_start, page_end);
+	ret = 0;
+	if (offset != PAGE_CACHE_SIZE) {
+		kaddr = kmap(page);
+		memset(kaddr + offset, 0, PAGE_CACHE_SIZE - offset);
+		flush_dcache_page(page);
+		kunmap(page);
+	}
+	ClearPageChecked(page);
+	set_page_dirty(page);
+	unlock_extent(io_tree, page_start, page_end, GFP_NOFS);
+
+out_unlock:
+	unlock_page(page);
+	page_cache_release(page);
+out:
+	return ret;
+}
+
+int btrfs_cont_expand(struct inode *inode, loff_t size)
+{
+	struct btrfs_trans_handle *trans;
+	struct btrfs_root *root = BTRFS_I(inode)->root;
+	struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
+	struct extent_map *em;
+	u64 mask = root->sectorsize - 1;
+	u64 hole_start = (inode->i_size + mask) & ~mask;
+	u64 block_end = (size + mask) & ~mask;
+	u64 last_byte;
+	u64 cur_offset;
+	u64 hole_size;
+	int err;
+
+	if (size <= hole_start)
+		return 0;
+
+	err = btrfs_check_free_space(root, 1, 0);
+	if (err)
+		return err;
+
+	btrfs_truncate_page(inode->i_mapping, inode->i_size);
+
+	while (1) {
+		struct btrfs_ordered_extent *ordered;
+		btrfs_wait_ordered_range(inode, hole_start,
+					 block_end - hole_start);
+		lock_extent(io_tree, hole_start, block_end - 1, GFP_NOFS);
+		ordered = btrfs_lookup_ordered_extent(inode, hole_start);
+		if (!ordered)
+			break;
+		unlock_extent(io_tree, hole_start, block_end - 1, GFP_NOFS);
+		btrfs_put_ordered_extent(ordered);
+	}
+
+	trans = btrfs_start_transaction(root, 1);
+	btrfs_set_trans_block_group(trans, inode);
+
+	cur_offset = hole_start;
+	while (1) {
+		em = btrfs_get_extent(inode, NULL, 0, cur_offset,
+				block_end - cur_offset, 0);
+		BUG_ON(IS_ERR(em) || !em);
+		last_byte = min(extent_map_end(em), block_end);
+		last_byte = (last_byte + mask) & ~mask;
+		if (test_bit(EXTENT_FLAG_VACANCY, &em->flags)) {
+			u64 hint_byte = 0;
+			hole_size = last_byte - cur_offset;
+			err = btrfs_drop_extents(trans, root, inode,
+						 cur_offset,
+						 cur_offset + hole_size,
+						 cur_offset, &hint_byte);
+			if (err)
+				break;
+			err = btrfs_insert_file_extent(trans, root,
+					inode->i_ino, cur_offset, 0,
+					0, hole_size, 0, hole_size,
+					0, 0, 0);
+			btrfs_drop_extent_cache(inode, hole_start,
+					last_byte - 1, 0);
+		}
+		free_extent_map(em);
+		cur_offset = last_byte;
+		if (err || cur_offset >= block_end)
+			break;
+	}
+
+	btrfs_end_transaction(trans, root);
+	unlock_extent(io_tree, hole_start, block_end - 1, GFP_NOFS);
+	return err;
+}
+
+static int btrfs_setattr(struct dentry *dentry, struct iattr *attr)
+{
+	struct inode *inode = dentry->d_inode;
+	int err;
+
+	err = inode_change_ok(inode, attr);
+	if (err)
+		return err;
+
+	if (S_ISREG(inode->i_mode) &&
+	    attr->ia_valid & ATTR_SIZE && attr->ia_size > inode->i_size) {
+		err = btrfs_cont_expand(inode, attr->ia_size);
+		if (err)
+			return err;
+	}
+
+	err = inode_setattr(inode, attr);
+
+	if (!err && ((attr->ia_valid & ATTR_MODE)))
+		err = btrfs_acl_chmod(inode);
+	return err;
+}
+
+void btrfs_delete_inode(struct inode *inode)
+{
+	struct btrfs_trans_handle *trans;
+	struct btrfs_root *root = BTRFS_I(inode)->root;
+	unsigned long nr;
+	int ret;
+
+	truncate_inode_pages(&inode->i_data, 0);
+	if (is_bad_inode(inode)) {
+		btrfs_orphan_del(NULL, inode);
+		goto no_delete;
+	}
+	btrfs_wait_ordered_range(inode, 0, (u64)-1);
+
+	btrfs_i_size_write(inode, 0);
+	trans = btrfs_join_transaction(root, 1);
+
+	btrfs_set_trans_block_group(trans, inode);
+	ret = btrfs_truncate_inode_items(trans, root, inode, inode->i_size, 0);
+	if (ret) {
+		btrfs_orphan_del(NULL, inode);
+		goto no_delete_lock;
+	}
+
+	btrfs_orphan_del(trans, inode);
+
+	nr = trans->blocks_used;
+	clear_inode(inode);
+
+	btrfs_end_transaction(trans, root);
+	btrfs_btree_balance_dirty(root, nr);
+	return;
+
+no_delete_lock:
+	nr = trans->blocks_used;
+	btrfs_end_transaction(trans, root);
+	btrfs_btree_balance_dirty(root, nr);
+no_delete:
+	clear_inode(inode);
+}
+
+/*
+ * this returns the key found in the dir entry in the location pointer.
+ * If no dir entries were found, location->objectid is 0.
+ */
+static int btrfs_inode_by_name(struct inode *dir, struct dentry *dentry,
+			       struct btrfs_key *location)
+{
+	const char *name = dentry->d_name.name;
+	int namelen = dentry->d_name.len;
+	struct btrfs_dir_item *di;
+	struct btrfs_path *path;
+	struct btrfs_root *root = BTRFS_I(dir)->root;
+	int ret = 0;
+
+	path = btrfs_alloc_path();
+	BUG_ON(!path);
+
+	di = btrfs_lookup_dir_item(NULL, root, path, dir->i_ino, name,
+				    namelen, 0);
+	if (IS_ERR(di))
+		ret = PTR_ERR(di);
+
+	if (!di || IS_ERR(di))
+		goto out_err;
+
+	btrfs_dir_item_key_to_cpu(path->nodes[0], di, location);
+out:
+	btrfs_free_path(path);
+	return ret;
+out_err:
+	location->objectid = 0;
+	goto out;
+}
+
+/*
+ * when we hit a tree root in a directory, the btrfs part of the inode
+ * needs to be changed to reflect the root directory of the tree root.  This
+ * is kind of like crossing a mount point.
+ */
+static int fixup_tree_root_location(struct btrfs_root *root,
+			     struct btrfs_key *location,
+			     struct btrfs_root **sub_root,
+			     struct dentry *dentry)
+{
+	struct btrfs_root_item *ri;
+
+	if (btrfs_key_type(location) != BTRFS_ROOT_ITEM_KEY)
+		return 0;
+	if (location->objectid == BTRFS_ROOT_TREE_OBJECTID)
+		return 0;
+
+	*sub_root = btrfs_read_fs_root(root->fs_info, location,
+					dentry->d_name.name,
+					dentry->d_name.len);
+	if (IS_ERR(*sub_root))
+		return PTR_ERR(*sub_root);
+
+	ri = &(*sub_root)->root_item;
+	location->objectid = btrfs_root_dirid(ri);
+	btrfs_set_key_type(location, BTRFS_INODE_ITEM_KEY);
+	location->offset = 0;
+
+	return 0;
+}
+
+static noinline void init_btrfs_i(struct inode *inode)
+{
+	struct btrfs_inode *bi = BTRFS_I(inode);
+
+	bi->i_acl = NULL;
+	bi->i_default_acl = NULL;
+
+	bi->generation = 0;
+	bi->sequence = 0;
+	bi->last_trans = 0;
+	bi->logged_trans = 0;
+	bi->delalloc_bytes = 0;
+	bi->disk_i_size = 0;
+	bi->flags = 0;
+	bi->index_cnt = (u64)-1;
+	bi->log_dirty_trans = 0;
+	extent_map_tree_init(&BTRFS_I(inode)->extent_tree, GFP_NOFS);
+	extent_io_tree_init(&BTRFS_I(inode)->io_tree,
+			     inode->i_mapping, GFP_NOFS);
+	extent_io_tree_init(&BTRFS_I(inode)->io_failure_tree,
+			     inode->i_mapping, GFP_NOFS);
+	INIT_LIST_HEAD(&BTRFS_I(inode)->delalloc_inodes);
+	btrfs_ordered_inode_tree_init(&BTRFS_I(inode)->ordered_tree);
+	mutex_init(&BTRFS_I(inode)->extent_mutex);
+	mutex_init(&BTRFS_I(inode)->log_mutex);
+}
+
+static int btrfs_init_locked_inode(struct inode *inode, void *p)
+{
+	struct btrfs_iget_args *args = p;
+	inode->i_ino = args->ino;
+	init_btrfs_i(inode);
+	BTRFS_I(inode)->root = args->root;
+	return 0;
+}
+
+static int btrfs_find_actor(struct inode *inode, void *opaque)
+{
+	struct btrfs_iget_args *args = opaque;
+	return args->ino == inode->i_ino &&
+		args->root == BTRFS_I(inode)->root;
+}
+
+struct inode *btrfs_ilookup(struct super_block *s, u64 objectid,
+			    struct btrfs_root *root, int wait)
+{
+	struct inode *inode;
+	struct btrfs_iget_args args;
+	args.ino = objectid;
+	args.root = root;
+
+	if (wait) {
+		inode = ilookup5(s, objectid, btrfs_find_actor,
+				 (void *)&args);
+	} else {
+		inode = ilookup5_nowait(s, objectid, btrfs_find_actor,
+					(void *)&args);
+	}
+	return inode;
+}
+
+struct inode *btrfs_iget_locked(struct super_block *s, u64 objectid,
+				struct btrfs_root *root)
+{
+	struct inode *inode;
+	struct btrfs_iget_args args;
+	args.ino = objectid;
+	args.root = root;
+
+	inode = iget5_locked(s, objectid, btrfs_find_actor,
+			     btrfs_init_locked_inode,
+			     (void *)&args);
+	return inode;
+}
+
+/* Get an inode object given its location and corresponding root.
+ * Returns in *is_new if the inode was read from disk
+ */
+struct inode *btrfs_iget(struct super_block *s, struct btrfs_key *location,
+			 struct btrfs_root *root, int *is_new)
+{
+	struct inode *inode;
+
+	inode = btrfs_iget_locked(s, location->objectid, root);
+	if (!inode)
+		return ERR_PTR(-EACCES);
+
+	if (inode->i_state & I_NEW) {
+		BTRFS_I(inode)->root = root;
+		memcpy(&BTRFS_I(inode)->location, location, sizeof(*location));
+		btrfs_read_locked_inode(inode);
+		unlock_new_inode(inode);
+		if (is_new)
+			*is_new = 1;
+	} else {
+		if (is_new)
+			*is_new = 0;
+	}
+
+	return inode;
+}
+
+struct inode *btrfs_lookup_dentry(struct inode *dir, struct dentry *dentry)
+{
+	struct inode *inode;
+	struct btrfs_inode *bi = BTRFS_I(dir);
+	struct btrfs_root *root = bi->root;
+	struct btrfs_root *sub_root = root;
+	struct btrfs_key location;
+	int ret, new;
+
+	if (dentry->d_name.len > BTRFS_NAME_LEN)
+		return ERR_PTR(-ENAMETOOLONG);
+
+	ret = btrfs_inode_by_name(dir, dentry, &location);
+
+	if (ret < 0)
+		return ERR_PTR(ret);
+
+	inode = NULL;
+	if (location.objectid) {
+		ret = fixup_tree_root_location(root, &location, &sub_root,
+						dentry);
+		if (ret < 0)
+			return ERR_PTR(ret);
+		if (ret > 0)
+			return ERR_PTR(-ENOENT);
+		inode = btrfs_iget(dir->i_sb, &location, sub_root, &new);
+		if (IS_ERR(inode))
+			return ERR_CAST(inode);
+	}
+	return inode;
+}
+
+static struct dentry *btrfs_lookup(struct inode *dir, struct dentry *dentry,
+				   struct nameidata *nd)
+{
+	struct inode *inode;
+
+	if (dentry->d_name.len > BTRFS_NAME_LEN)
+		return ERR_PTR(-ENAMETOOLONG);
+
+	inode = btrfs_lookup_dentry(dir, dentry);
+	if (IS_ERR(inode))
+		return ERR_CAST(inode);
+
+	return d_splice_alias(inode, dentry);
+}
+
+static unsigned char btrfs_filetype_table[] = {
+	DT_UNKNOWN, DT_REG, DT_DIR, DT_CHR, DT_BLK, DT_FIFO, DT_SOCK, DT_LNK
+};
+
+static int btrfs_real_readdir(struct file *filp, void *dirent,
+			      filldir_t filldir)
+{
+	struct inode *inode = filp->f_dentry->d_inode;
+	struct btrfs_root *root = BTRFS_I(inode)->root;
+	struct btrfs_item *item;
+	struct btrfs_dir_item *di;
+	struct btrfs_key key;
+	struct btrfs_key found_key;
+	struct btrfs_path *path;
+	int ret;
+	u32 nritems;
+	struct extent_buffer *leaf;
+	int slot;
+	int advance;
+	unsigned char d_type;
+	int over = 0;
+	u32 di_cur;
+	u32 di_total;
+	u32 di_len;
+	int key_type = BTRFS_DIR_INDEX_KEY;
+	char tmp_name[32];
+	char *name_ptr;
+	int name_len;
+
+	/* FIXME, use a real flag for deciding about the key type */
+	if (root->fs_info->tree_root == root)
+		key_type = BTRFS_DIR_ITEM_KEY;
+
+	/* special case for "." */
+	if (filp->f_pos == 0) {
+		over = filldir(dirent, ".", 1,
+			       1, inode->i_ino,
+			       DT_DIR);
+		if (over)
+			return 0;
+		filp->f_pos = 1;
+	}
+	/* special case for .., just use the back ref */
+	if (filp->f_pos == 1) {
+		u64 pino = parent_ino(filp->f_path.dentry);
+		over = filldir(dirent, "..", 2,
+			       2, pino, DT_DIR);
+		if (over)
+			return 0;
+		filp->f_pos = 2;
+	}
+	path = btrfs_alloc_path();
+	path->reada = 2;
+
+	btrfs_set_key_type(&key, key_type);
+	key.offset = filp->f_pos;
+	key.objectid = inode->i_ino;
+
+	ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
+	if (ret < 0)
+		goto err;
+	advance = 0;
+
+	while (1) {
+		leaf = path->nodes[0];
+		nritems = btrfs_header_nritems(leaf);
+		slot = path->slots[0];
+		if (advance || slot >= nritems) {
+			if (slot >= nritems - 1) {
+				ret = btrfs_next_leaf(root, path);
+				if (ret)
+					break;
+				leaf = path->nodes[0];
+				nritems = btrfs_header_nritems(leaf);
+				slot = path->slots[0];
+			} else {
+				slot++;
+				path->slots[0]++;
+			}
+		}
+
+		advance = 1;
+		item = btrfs_item_nr(leaf, slot);
+		btrfs_item_key_to_cpu(leaf, &found_key, slot);
+
+		if (found_key.objectid != key.objectid)
+			break;
+		if (btrfs_key_type(&found_key) != key_type)
+			break;
+		if (found_key.offset < filp->f_pos)
+			continue;
+
+		filp->f_pos = found_key.offset;
+
+		di = btrfs_item_ptr(leaf, slot, struct btrfs_dir_item);
+		di_cur = 0;
+		di_total = btrfs_item_size(leaf, item);
+
+		while (di_cur < di_total) {
+			struct btrfs_key location;
+
+			name_len = btrfs_dir_name_len(leaf, di);
+			if (name_len <= sizeof(tmp_name)) {
+				name_ptr = tmp_name;
+			} else {
+				name_ptr = kmalloc(name_len, GFP_NOFS);
+				if (!name_ptr) {
+					ret = -ENOMEM;
+					goto err;
+				}
+			}
+			read_extent_buffer(leaf, name_ptr,
+					   (unsigned long)(di + 1), name_len);
+
+			d_type = btrfs_filetype_table[btrfs_dir_type(leaf, di)];
+			btrfs_dir_item_key_to_cpu(leaf, di, &location);
+
+			/* is this a reference to our own snapshot? If so
+			 * skip it
+			 */
+			if (location.type == BTRFS_ROOT_ITEM_KEY &&
+			    location.objectid == root->root_key.objectid) {
+				over = 0;
+				goto skip;
+			}
+			over = filldir(dirent, name_ptr, name_len,
+				       found_key.offset, location.objectid,
+				       d_type);
+
+skip:
+			if (name_ptr != tmp_name)
+				kfree(name_ptr);
+
+			if (over)
+				goto nopos;
+			di_len = btrfs_dir_name_len(leaf, di) +
+				 btrfs_dir_data_len(leaf, di) + sizeof(*di);
+			di_cur += di_len;
+			di = (struct btrfs_dir_item *)((char *)di + di_len);
+		}
+	}
+
+	/* Reached end of directory/root. Bump pos past the last item. */
+	if (key_type == BTRFS_DIR_INDEX_KEY)
+		filp->f_pos = INT_LIMIT(typeof(filp->f_pos));
+	else
+		filp->f_pos++;
+nopos:
+	ret = 0;
+err:
+	btrfs_free_path(path);
+	return ret;
+}
+
+int btrfs_write_inode(struct inode *inode, int wait)
+{
+	struct btrfs_root *root = BTRFS_I(inode)->root;
+	struct btrfs_trans_handle *trans;
+	int ret = 0;
+
+	if (root->fs_info->btree_inode == inode)
+		return 0;
+
+	if (wait) {
+		trans = btrfs_join_transaction(root, 1);
+		btrfs_set_trans_block_group(trans, inode);
+		ret = btrfs_commit_transaction(trans, root);
+	}
+	return ret;
+}
+
+/*
+ * This is somewhat expensive, updating the tree every time the
+ * inode changes.  But, it is most likely to find the inode in cache.
+ * FIXME, needs more benchmarking...there are no reasons other than performance
+ * to keep or drop this code.
+ */
+void btrfs_dirty_inode(struct inode *inode)
+{
+	struct btrfs_root *root = BTRFS_I(inode)->root;
+	struct btrfs_trans_handle *trans;
+
+	trans = btrfs_join_transaction(root, 1);
+	btrfs_set_trans_block_group(trans, inode);
+	btrfs_update_inode(trans, root, inode);
+	btrfs_end_transaction(trans, root);
+}
+
+/*
+ * find the highest existing sequence number in a directory
+ * and then set the in-memory index_cnt variable to reflect
+ * free sequence numbers
+ */
+static int btrfs_set_inode_index_count(struct inode *inode)
+{
+	struct btrfs_root *root = BTRFS_I(inode)->root;
+	struct btrfs_key key, found_key;
+	struct btrfs_path *path;
+	struct extent_buffer *leaf;
+	int ret;
+
+	key.objectid = inode->i_ino;
+	btrfs_set_key_type(&key, BTRFS_DIR_INDEX_KEY);
+	key.offset = (u64)-1;
+
+	path = btrfs_alloc_path();
+	if (!path)
+		return -ENOMEM;
+
+	ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
+	if (ret < 0)
+		goto out;
+	/* FIXME: we should be able to handle this */
+	if (ret == 0)
+		goto out;
+	ret = 0;
+
+	/*
+	 * MAGIC NUMBER EXPLANATION:
+	 * since we search a directory based on f_pos we have to start at 2
+	 * since '.' and '..' have f_pos of 0 and 1 respectively, so everybody
+	 * else has to start at 2
+	 */
+	if (path->slots[0] == 0) {
+		BTRFS_I(inode)->index_cnt = 2;
+		goto out;
+	}
+
+	path->slots[0]--;
+
+	leaf = path->nodes[0];
+	btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
+
+	if (found_key.objectid != inode->i_ino ||
+	    btrfs_key_type(&found_key) != BTRFS_DIR_INDEX_KEY) {
+		BTRFS_I(inode)->index_cnt = 2;
+		goto out;
+	}
+
+	BTRFS_I(inode)->index_cnt = found_key.offset + 1;
+out:
+	btrfs_free_path(path);
+	return ret;
+}
+
+/*
+ * helper to find a free sequence number in a given directory.  This current
+ * code is very simple, later versions will do smarter things in the btree
+ */
+int btrfs_set_inode_index(struct inode *dir, u64 *index)
+{
+	int ret = 0;
+
+	if (BTRFS_I(dir)->index_cnt == (u64)-1) {
+		ret = btrfs_set_inode_index_count(dir);
+		if (ret)
+			return ret;
+	}
+
+	*index = BTRFS_I(dir)->index_cnt;
+	BTRFS_I(dir)->index_cnt++;
+
+	return ret;
+}
+
+static struct inode *btrfs_new_inode(struct btrfs_trans_handle *trans,
+				     struct btrfs_root *root,
+				     struct inode *dir,
+				     const char *name, int name_len,
+				     u64 ref_objectid, u64 objectid,
+				     u64 alloc_hint, int mode, u64 *index)
+{
+	struct inode *inode;
+	struct btrfs_inode_item *inode_item;
+	struct btrfs_key *location;
+	struct btrfs_path *path;
+	struct btrfs_inode_ref *ref;
+	struct btrfs_key key[2];
+	u32 sizes[2];
+	unsigned long ptr;
+	int ret;
+	int owner;
+
+	path = btrfs_alloc_path();
+	BUG_ON(!path);
+
+	inode = new_inode(root->fs_info->sb);
+	if (!inode)
+		return ERR_PTR(-ENOMEM);
+
+	if (dir) {
+		ret = btrfs_set_inode_index(dir, index);
+		if (ret)
+			return ERR_PTR(ret);
+	}
+	/*
+	 * index_cnt is ignored for everything but a dir,
+	 * btrfs_get_inode_index_count has an explanation for the magic
+	 * number
+	 */
+	init_btrfs_i(inode);
+	BTRFS_I(inode)->index_cnt = 2;
+	BTRFS_I(inode)->root = root;
+	BTRFS_I(inode)->generation = trans->transid;
+
+	if (mode & S_IFDIR)
+		owner = 0;
+	else
+		owner = 1;
+	BTRFS_I(inode)->block_group =
+			btrfs_find_block_group(root, 0, alloc_hint, owner);
+	if ((mode & S_IFREG)) {
+		if (btrfs_test_opt(root, NODATASUM))
+			btrfs_set_flag(inode, NODATASUM);
+		if (btrfs_test_opt(root, NODATACOW))
+			btrfs_set_flag(inode, NODATACOW);
+	}
+
+	key[0].objectid = objectid;
+	btrfs_set_key_type(&key[0], BTRFS_INODE_ITEM_KEY);
+	key[0].offset = 0;
+
+	key[1].objectid = objectid;
+	btrfs_set_key_type(&key[1], BTRFS_INODE_REF_KEY);
+	key[1].offset = ref_objectid;
+
+	sizes[0] = sizeof(struct btrfs_inode_item);
+	sizes[1] = name_len + sizeof(*ref);
+
+	ret = btrfs_insert_empty_items(trans, root, path, key, sizes, 2);
+	if (ret != 0)
+		goto fail;
+
+	if (objectid > root->highest_inode)
+		root->highest_inode = objectid;
+
+	inode->i_uid = current_fsuid();
+	inode->i_gid = current_fsgid();
+	inode->i_mode = mode;
+	inode->i_ino = objectid;
+	inode_set_bytes(inode, 0);
+	inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
+	inode_item = btrfs_item_ptr(path->nodes[0], path->slots[0],
+				  struct btrfs_inode_item);
+	fill_inode_item(trans, path->nodes[0], inode_item, inode);
+
+	ref = btrfs_item_ptr(path->nodes[0], path->slots[0] + 1,
+			     struct btrfs_inode_ref);
+	btrfs_set_inode_ref_name_len(path->nodes[0], ref, name_len);
+	btrfs_set_inode_ref_index(path->nodes[0], ref, *index);
+	ptr = (unsigned long)(ref + 1);
+	write_extent_buffer(path->nodes[0], name, ptr, name_len);
+
+	btrfs_mark_buffer_dirty(path->nodes[0]);
+	btrfs_free_path(path);
+
+	location = &BTRFS_I(inode)->location;
+	location->objectid = objectid;
+	location->offset = 0;
+	btrfs_set_key_type(location, BTRFS_INODE_ITEM_KEY);
+
+	insert_inode_hash(inode);
+	return inode;
+fail:
+	if (dir)
+		BTRFS_I(dir)->index_cnt--;
+	btrfs_free_path(path);
+	return ERR_PTR(ret);
+}
+
+static inline u8 btrfs_inode_type(struct inode *inode)
+{
+	return btrfs_type_by_mode[(inode->i_mode & S_IFMT) >> S_SHIFT];
+}
+
+/*
+ * utility function to add 'inode' into 'parent_inode' with
+ * a give name and a given sequence number.
+ * if 'add_backref' is true, also insert a backref from the
+ * inode to the parent directory.
+ */
+int btrfs_add_link(struct btrfs_trans_handle *trans,
+		   struct inode *parent_inode, struct inode *inode,
+		   const char *name, int name_len, int add_backref, u64 index)
+{
+	int ret;
+	struct btrfs_key key;
+	struct btrfs_root *root = BTRFS_I(parent_inode)->root;
+
+	key.objectid = inode->i_ino;
+	btrfs_set_key_type(&key, BTRFS_INODE_ITEM_KEY);
+	key.offset = 0;
+
+	ret = btrfs_insert_dir_item(trans, root, name, name_len,
+				    parent_inode->i_ino,
+				    &key, btrfs_inode_type(inode),
+				    index);
+	if (ret == 0) {
+		if (add_backref) {
+			ret = btrfs_insert_inode_ref(trans, root,
+						     name, name_len,
+						     inode->i_ino,
+						     parent_inode->i_ino,
+						     index);
+		}
+		btrfs_i_size_write(parent_inode, parent_inode->i_size +
+				   name_len * 2);
+		parent_inode->i_mtime = parent_inode->i_ctime = CURRENT_TIME;
+		ret = btrfs_update_inode(trans, root, parent_inode);
+	}
+	return ret;
+}
+
+static int btrfs_add_nondir(struct btrfs_trans_handle *trans,
+			    struct dentry *dentry, struct inode *inode,
+			    int backref, u64 index)
+{
+	int err = btrfs_add_link(trans, dentry->d_parent->d_inode,
+				 inode, dentry->d_name.name,
+				 dentry->d_name.len, backref, index);
+	if (!err) {
+		d_instantiate(dentry, inode);
+		return 0;
+	}
+	if (err > 0)
+		err = -EEXIST;
+	return err;
+}
+
+static int btrfs_mknod(struct inode *dir, struct dentry *dentry,
+			int mode, dev_t rdev)
+{
+	struct btrfs_trans_handle *trans;
+	struct btrfs_root *root = BTRFS_I(dir)->root;
+	struct inode *inode = NULL;
+	int err;
+	int drop_inode = 0;
+	u64 objectid;
+	unsigned long nr = 0;
+	u64 index = 0;
+
+	if (!new_valid_dev(rdev))
+		return -EINVAL;
+
+	err = btrfs_check_free_space(root, 1, 0);
+	if (err)
+		goto fail;
+
+	trans = btrfs_start_transaction(root, 1);
+	btrfs_set_trans_block_group(trans, dir);
+
+	err = btrfs_find_free_objectid(trans, root, dir->i_ino, &objectid);
+	if (err) {
+		err = -ENOSPC;
+		goto out_unlock;
+	}
+
+	inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
+				dentry->d_name.len,
+				dentry->d_parent->d_inode->i_ino, objectid,
+				BTRFS_I(dir)->block_group, mode, &index);
+	err = PTR_ERR(inode);
+	if (IS_ERR(inode))
+		goto out_unlock;
+
+	err = btrfs_init_acl(inode, dir);
+	if (err) {
+		drop_inode = 1;
+		goto out_unlock;
+	}
+
+	btrfs_set_trans_block_group(trans, inode);
+	err = btrfs_add_nondir(trans, dentry, inode, 0, index);
+	if (err)
+		drop_inode = 1;
+	else {
+		inode->i_op = &btrfs_special_inode_operations;
+		init_special_inode(inode, inode->i_mode, rdev);
+		btrfs_update_inode(trans, root, inode);
+	}
+	dir->i_sb->s_dirt = 1;
+	btrfs_update_inode_block_group(trans, inode);
+	btrfs_update_inode_block_group(trans, dir);
+out_unlock:
+	nr = trans->blocks_used;
+	btrfs_end_transaction_throttle(trans, root);
+fail:
+	if (drop_inode) {
+		inode_dec_link_count(inode);
+		iput(inode);
+	}
+	btrfs_btree_balance_dirty(root, nr);
+	return err;
+}
+
+static int btrfs_create(struct inode *dir, struct dentry *dentry,
+			int mode, struct nameidata *nd)
+{
+	struct btrfs_trans_handle *trans;
+	struct btrfs_root *root = BTRFS_I(dir)->root;
+	struct inode *inode = NULL;
+	int err;
+	int drop_inode = 0;
+	unsigned long nr = 0;
+	u64 objectid;
+	u64 index = 0;
+
+	err = btrfs_check_free_space(root, 1, 0);
+	if (err)
+		goto fail;
+	trans = btrfs_start_transaction(root, 1);
+	btrfs_set_trans_block_group(trans, dir);
+
+	err = btrfs_find_free_objectid(trans, root, dir->i_ino, &objectid);
+	if (err) {
+		err = -ENOSPC;
+		goto out_unlock;
+	}
+
+	inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
+				dentry->d_name.len,
+				dentry->d_parent->d_inode->i_ino,
+				objectid, BTRFS_I(dir)->block_group, mode,
+				&index);
+	err = PTR_ERR(inode);
+	if (IS_ERR(inode))
+		goto out_unlock;
+
+	err = btrfs_init_acl(inode, dir);
+	if (err) {
+		drop_inode = 1;
+		goto out_unlock;
+	}
+
+	btrfs_set_trans_block_group(trans, inode);
+	err = btrfs_add_nondir(trans, dentry, inode, 0, index);
+	if (err)
+		drop_inode = 1;
+	else {
+		inode->i_mapping->a_ops = &btrfs_aops;
+		inode->i_mapping->backing_dev_info = &root->fs_info->bdi;
+		inode->i_fop = &btrfs_file_operations;
+		inode->i_op = &btrfs_file_inode_operations;
+		BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
+	}
+	dir->i_sb->s_dirt = 1;
+	btrfs_update_inode_block_group(trans, inode);
+	btrfs_update_inode_block_group(trans, dir);
+out_unlock:
+	nr = trans->blocks_used;
+	btrfs_end_transaction_throttle(trans, root);
+fail:
+	if (drop_inode) {
+		inode_dec_link_count(inode);
+		iput(inode);
+	}
+	btrfs_btree_balance_dirty(root, nr);
+	return err;
+}
+
+static int btrfs_link(struct dentry *old_dentry, struct inode *dir,
+		      struct dentry *dentry)
+{
+	struct btrfs_trans_handle *trans;
+	struct btrfs_root *root = BTRFS_I(dir)->root;
+	struct inode *inode = old_dentry->d_inode;
+	u64 index;
+	unsigned long nr = 0;
+	int err;
+	int drop_inode = 0;
+
+	if (inode->i_nlink == 0)
+		return -ENOENT;
+
+	btrfs_inc_nlink(inode);
+	err = btrfs_check_free_space(root, 1, 0);
+	if (err)
+		goto fail;
+	err = btrfs_set_inode_index(dir, &index);
+	if (err)
+		goto fail;
+
+	trans = btrfs_start_transaction(root, 1);
+
+	btrfs_set_trans_block_group(trans, dir);
+	atomic_inc(&inode->i_count);
+
+	err = btrfs_add_nondir(trans, dentry, inode, 1, index);
+
+	if (err)
+		drop_inode = 1;
+
+	dir->i_sb->s_dirt = 1;
+	btrfs_update_inode_block_group(trans, dir);
+	err = btrfs_update_inode(trans, root, inode);
+
+	if (err)
+		drop_inode = 1;
+
+	nr = trans->blocks_used;
+	btrfs_end_transaction_throttle(trans, root);
+fail:
+	if (drop_inode) {
+		inode_dec_link_count(inode);
+		iput(inode);
+	}
+	btrfs_btree_balance_dirty(root, nr);
+	return err;
+}
+
+static int btrfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
+{
+	struct inode *inode = NULL;
+	struct btrfs_trans_handle *trans;
+	struct btrfs_root *root = BTRFS_I(dir)->root;
+	int err = 0;
+	int drop_on_err = 0;
+	u64 objectid = 0;
+	u64 index = 0;
+	unsigned long nr = 1;
+
+	err = btrfs_check_free_space(root, 1, 0);
+	if (err)
+		goto out_unlock;
+
+	trans = btrfs_start_transaction(root, 1);
+	btrfs_set_trans_block_group(trans, dir);
+
+	if (IS_ERR(trans)) {
+		err = PTR_ERR(trans);
+		goto out_unlock;
+	}
+
+	err = btrfs_find_free_objectid(trans, root, dir->i_ino, &objectid);
+	if (err) {
+		err = -ENOSPC;
+		goto out_unlock;
+	}
+
+	inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
+				dentry->d_name.len,
+				dentry->d_parent->d_inode->i_ino, objectid,
+				BTRFS_I(dir)->block_group, S_IFDIR | mode,
+				&index);
+	if (IS_ERR(inode)) {
+		err = PTR_ERR(inode);
+		goto out_fail;
+	}
+
+	drop_on_err = 1;
+
+	err = btrfs_init_acl(inode, dir);
+	if (err)
+		goto out_fail;
+
+	inode->i_op = &btrfs_dir_inode_operations;
+	inode->i_fop = &btrfs_dir_file_operations;
+	btrfs_set_trans_block_group(trans, inode);
+
+	btrfs_i_size_write(inode, 0);
+	err = btrfs_update_inode(trans, root, inode);
+	if (err)
+		goto out_fail;
+
+	err = btrfs_add_link(trans, dentry->d_parent->d_inode,
+				 inode, dentry->d_name.name,
+				 dentry->d_name.len, 0, index);
+	if (err)
+		goto out_fail;
+
+	d_instantiate(dentry, inode);
+	drop_on_err = 0;
+	dir->i_sb->s_dirt = 1;
+	btrfs_update_inode_block_group(trans, inode);
+	btrfs_update_inode_block_group(trans, dir);
+
+out_fail:
+	nr = trans->blocks_used;
+	btrfs_end_transaction_throttle(trans, root);
+
+out_unlock:
+	if (drop_on_err)
+		iput(inode);
+	btrfs_btree_balance_dirty(root, nr);
+	return err;
+}
+
+static ssize_t btrfs_direct_IO(int rw, struct kiocb *iocb,
+			const struct iovec *iov, loff_t offset,
+			unsigned long nr_segs)
+{
+	return -EINVAL;
+}
+
+static sector_t btrfs_bmap(struct address_space *mapping, sector_t iblock)
+{
+	return extent_bmap(mapping, iblock, btrfs_get_extent);
+}
+
+int btrfs_readpage(struct file *file, struct page *page)
+{
+	struct extent_io_tree *tree;
+	tree = &BTRFS_I(page->mapping->host)->io_tree;
+	return extent_read_full_page(tree, page, btrfs_get_extent);
+}
+
+static int btrfs_writepage(struct page *page, struct writeback_control *wbc)
+{
+	struct extent_io_tree *tree;
+
+
+	if (current->flags & PF_MEMALLOC) {
+		redirty_page_for_writepage(wbc, page);
+		unlock_page(page);
+		return 0;
+	}
+	tree = &BTRFS_I(page->mapping->host)->io_tree;
+	return extent_write_full_page(tree, page, btrfs_get_extent, wbc);
+}
+
+int btrfs_writepages(struct address_space *mapping,
+		     struct writeback_control *wbc)
+{
+	struct extent_io_tree *tree;
+
+	tree = &BTRFS_I(mapping->host)->io_tree;
+	return extent_writepages(tree, mapping, btrfs_get_extent, wbc);
+}
+
+static int
+btrfs_readpages(struct file *file, struct address_space *mapping,
+		struct list_head *pages, unsigned nr_pages)
+{
+	struct extent_io_tree *tree;
+	tree = &BTRFS_I(mapping->host)->io_tree;
+	return extent_readpages(tree, mapping, pages, nr_pages,
+				btrfs_get_extent);
+}
+static int __btrfs_releasepage(struct page *page, gfp_t gfp_flags)
+{
+	struct extent_io_tree *tree;
+	struct extent_map_tree *map;
+	int ret;
+
+	tree = &BTRFS_I(page->mapping->host)->io_tree;
+	map = &BTRFS_I(page->mapping->host)->extent_tree;
+	ret = try_release_extent_mapping(map, tree, page, gfp_flags);
+	if (ret == 1) {
+		ClearPagePrivate(page);
+		set_page_private(page, 0);
+		page_cache_release(page);
+	}
+	return ret;
+}
+
+static int btrfs_releasepage(struct page *page, gfp_t gfp_flags)
+{
+	if (PageWriteback(page) || PageDirty(page))
+		return 0;
+	return __btrfs_releasepage(page, gfp_flags);
+}
+
+static void btrfs_invalidatepage(struct page *page, unsigned long offset)
+{
+	struct extent_io_tree *tree;
+	struct btrfs_ordered_extent *ordered;
+	u64 page_start = page_offset(page);
+	u64 page_end = page_start + PAGE_CACHE_SIZE - 1;
+
+	wait_on_page_writeback(page);
+	tree = &BTRFS_I(page->mapping->host)->io_tree;
+	if (offset) {
+		btrfs_releasepage(page, GFP_NOFS);
+		return;
+	}
+
+	lock_extent(tree, page_start, page_end, GFP_NOFS);
+	ordered = btrfs_lookup_ordered_extent(page->mapping->host,
+					   page_offset(page));
+	if (ordered) {
+		/*
+		 * IO on this page will never be started, so we need
+		 * to account for any ordered extents now
+		 */
+		clear_extent_bit(tree, page_start, page_end,
+				 EXTENT_DIRTY | EXTENT_DELALLOC |
+				 EXTENT_LOCKED, 1, 0, GFP_NOFS);
+		btrfs_finish_ordered_io(page->mapping->host,
+					page_start, page_end);
+		btrfs_put_ordered_extent(ordered);
+		lock_extent(tree, page_start, page_end, GFP_NOFS);
+	}
+	clear_extent_bit(tree, page_start, page_end,
+		 EXTENT_LOCKED | EXTENT_DIRTY | EXTENT_DELALLOC |
+		 EXTENT_ORDERED,
+		 1, 1, GFP_NOFS);
+	__btrfs_releasepage(page, GFP_NOFS);
+
+	ClearPageChecked(page);
+	if (PagePrivate(page)) {
+		ClearPagePrivate(page);
+		set_page_private(page, 0);
+		page_cache_release(page);
+	}
+}
+
+/*
+ * btrfs_page_mkwrite() is not allowed to change the file size as it gets
+ * called from a page fault handler when a page is first dirtied. Hence we must
+ * be careful to check for EOF conditions here. We set the page up correctly
+ * for a written page which means we get ENOSPC checking when writing into
+ * holes and correct delalloc and unwritten extent mapping on filesystems that
+ * support these features.
+ *
+ * We are not allowed to take the i_mutex here so we have to play games to
+ * protect against truncate races as the page could now be beyond EOF.  Because
+ * vmtruncate() writes the inode size before removing pages, once we have the
+ * page lock we can determine safely if the page is beyond EOF. If it is not
+ * beyond EOF, then the page is guaranteed safe against truncation until we
+ * unlock the page.
+ */
+int btrfs_page_mkwrite(struct vm_area_struct *vma, struct page *page)
+{
+	struct inode *inode = fdentry(vma->vm_file)->d_inode;
+	struct btrfs_root *root = BTRFS_I(inode)->root;
+	struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
+	struct btrfs_ordered_extent *ordered;
+	char *kaddr;
+	unsigned long zero_start;
+	loff_t size;
+	int ret;
+	u64 page_start;
+	u64 page_end;
+
+	ret = btrfs_check_free_space(root, PAGE_CACHE_SIZE, 0);
+	if (ret)
+		goto out;
+
+	ret = -EINVAL;
+again:
+	lock_page(page);
+	size = i_size_read(inode);
+	page_start = page_offset(page);
+	page_end = page_start + PAGE_CACHE_SIZE - 1;
+
+	if ((page->mapping != inode->i_mapping) ||
+	    (page_start >= size)) {
+		/* page got truncated out from underneath us */
+		goto out_unlock;
+	}
+	wait_on_page_writeback(page);
+
+	lock_extent(io_tree, page_start, page_end, GFP_NOFS);
+	set_page_extent_mapped(page);
+
+	/*
+	 * we can't set the delalloc bits if there are pending ordered
+	 * extents.  Drop our locks and wait for them to finish
+	 */
+	ordered = btrfs_lookup_ordered_extent(inode, page_start);
+	if (ordered) {
+		unlock_extent(io_tree, page_start, page_end, GFP_NOFS);
+		unlock_page(page);
+		btrfs_start_ordered_extent(inode, ordered, 1);
+		btrfs_put_ordered_extent(ordered);
+		goto again;
+	}
+
+	btrfs_set_extent_delalloc(inode, page_start, page_end);
+	ret = 0;
+
+	/* page is wholly or partially inside EOF */
+	if (page_start + PAGE_CACHE_SIZE > size)
+		zero_start = size & ~PAGE_CACHE_MASK;
+	else
+		zero_start = PAGE_CACHE_SIZE;
+
+	if (zero_start != PAGE_CACHE_SIZE) {
+		kaddr = kmap(page);
+		memset(kaddr + zero_start, 0, PAGE_CACHE_SIZE - zero_start);
+		flush_dcache_page(page);
+		kunmap(page);
+	}
+	ClearPageChecked(page);
+	set_page_dirty(page);
+	unlock_extent(io_tree, page_start, page_end, GFP_NOFS);
+
+out_unlock:
+	unlock_page(page);
+out:
+	return ret;
+}
+
+static void btrfs_truncate(struct inode *inode)
+{
+	struct btrfs_root *root = BTRFS_I(inode)->root;
+	int ret;
+	struct btrfs_trans_handle *trans;
+	unsigned long nr;
+	u64 mask = root->sectorsize - 1;
+
+	if (!S_ISREG(inode->i_mode))
+		return;
+	if (IS_APPEND(inode) || IS_IMMUTABLE(inode))
+		return;
+
+	btrfs_truncate_page(inode->i_mapping, inode->i_size);
+	btrfs_wait_ordered_range(inode, inode->i_size & (~mask), (u64)-1);
+
+	trans = btrfs_start_transaction(root, 1);
+	btrfs_set_trans_block_group(trans, inode);
+	btrfs_i_size_write(inode, inode->i_size);
+
+	ret = btrfs_orphan_add(trans, inode);
+	if (ret)
+		goto out;
+	/* FIXME, add redo link to tree so we don't leak on crash */
+	ret = btrfs_truncate_inode_items(trans, root, inode, inode->i_size,
+				      BTRFS_EXTENT_DATA_KEY);
+	btrfs_update_inode(trans, root, inode);
+
+	ret = btrfs_orphan_del(trans, inode);
+	BUG_ON(ret);
+
+out:
+	nr = trans->blocks_used;
+	ret = btrfs_end_transaction_throttle(trans, root);
+	BUG_ON(ret);
+	btrfs_btree_balance_dirty(root, nr);
+}
+
+/*
+ * create a new subvolume directory/inode (helper for the ioctl).
+ */
+int btrfs_create_subvol_root(struct btrfs_trans_handle *trans,
+			     struct btrfs_root *new_root, struct dentry *dentry,
+			     u64 new_dirid, u64 alloc_hint)
+{
+	struct inode *inode;
+	int error;
+	u64 index = 0;
+
+	inode = btrfs_new_inode(trans, new_root, NULL, "..", 2, new_dirid,
+				new_dirid, alloc_hint, S_IFDIR | 0700, &index);
+	if (IS_ERR(inode))
+		return PTR_ERR(inode);
+	inode->i_op = &btrfs_dir_inode_operations;
+	inode->i_fop = &btrfs_dir_file_operations;
+
+	inode->i_nlink = 1;
+	btrfs_i_size_write(inode, 0);
+
+	error = btrfs_update_inode(trans, new_root, inode);
+	if (error)
+		return error;
+
+	d_instantiate(dentry, inode);
+	return 0;
+}
+
+/* helper function for file defrag and space balancing.  This
+ * forces readahead on a given range of bytes in an inode
+ */
+unsigned long btrfs_force_ra(struct address_space *mapping,
+			      struct file_ra_state *ra, struct file *file,
+			      pgoff_t offset, pgoff_t last_index)
+{
+	pgoff_t req_size = last_index - offset + 1;
+
+	page_cache_sync_readahead(mapping, ra, file, offset, req_size);
+	return offset + req_size;
+}
+
+struct inode *btrfs_alloc_inode(struct super_block *sb)
+{
+	struct btrfs_inode *ei;
+
+	ei = kmem_cache_alloc(btrfs_inode_cachep, GFP_NOFS);
+	if (!ei)
+		return NULL;
+	ei->last_trans = 0;
+	ei->logged_trans = 0;
+	btrfs_ordered_inode_tree_init(&ei->ordered_tree);
+	ei->i_acl = BTRFS_ACL_NOT_CACHED;
+	ei->i_default_acl = BTRFS_ACL_NOT_CACHED;
+	INIT_LIST_HEAD(&ei->i_orphan);
+	return &ei->vfs_inode;
+}
+
+void btrfs_destroy_inode(struct inode *inode)
+{
+	struct btrfs_ordered_extent *ordered;
+	WARN_ON(!list_empty(&inode->i_dentry));
+	WARN_ON(inode->i_data.nrpages);
+
+	if (BTRFS_I(inode)->i_acl &&
+	    BTRFS_I(inode)->i_acl != BTRFS_ACL_NOT_CACHED)
+		posix_acl_release(BTRFS_I(inode)->i_acl);
+	if (BTRFS_I(inode)->i_default_acl &&
+	    BTRFS_I(inode)->i_default_acl != BTRFS_ACL_NOT_CACHED)
+		posix_acl_release(BTRFS_I(inode)->i_default_acl);
+
+	spin_lock(&BTRFS_I(inode)->root->list_lock);
+	if (!list_empty(&BTRFS_I(inode)->i_orphan)) {
+		printk(KERN_ERR "BTRFS: inode %lu: inode still on the orphan"
+		       " list\n", inode->i_ino);
+		dump_stack();
+	}
+	spin_unlock(&BTRFS_I(inode)->root->list_lock);
+
+	while (1) {
+		ordered = btrfs_lookup_first_ordered_extent(inode, (u64)-1);
+		if (!ordered)
+			break;
+		else {
+			printk(KERN_ERR "btrfs found ordered "
+			       "extent %llu %llu on inode cleanup\n",
+			       (unsigned long long)ordered->file_offset,
+			       (unsigned long long)ordered->len);
+			btrfs_remove_ordered_extent(inode, ordered);
+			btrfs_put_ordered_extent(ordered);
+			btrfs_put_ordered_extent(ordered);
+		}
+	}
+	btrfs_drop_extent_cache(inode, 0, (u64)-1, 0);
+	kmem_cache_free(btrfs_inode_cachep, BTRFS_I(inode));
+}
+
+static void init_once(void *foo)
+{
+	struct btrfs_inode *ei = (struct btrfs_inode *) foo;
+
+	inode_init_once(&ei->vfs_inode);
+}
+
+void btrfs_destroy_cachep(void)
+{
+	if (btrfs_inode_cachep)
+		kmem_cache_destroy(btrfs_inode_cachep);
+	if (btrfs_trans_handle_cachep)
+		kmem_cache_destroy(btrfs_trans_handle_cachep);
+	if (btrfs_transaction_cachep)
+		kmem_cache_destroy(btrfs_transaction_cachep);
+	if (btrfs_bit_radix_cachep)
+		kmem_cache_destroy(btrfs_bit_radix_cachep);
+	if (btrfs_path_cachep)
+		kmem_cache_destroy(btrfs_path_cachep);
+}
+
+struct kmem_cache *btrfs_cache_create(const char *name, size_t size,
+				       unsigned long extra_flags,
+				       void (*ctor)(void *))
+{
+	return kmem_cache_create(name, size, 0, (SLAB_RECLAIM_ACCOUNT |
+				 SLAB_MEM_SPREAD | extra_flags), ctor);
+}
+
+int btrfs_init_cachep(void)
+{
+	btrfs_inode_cachep = btrfs_cache_create("btrfs_inode_cache",
+					  sizeof(struct btrfs_inode),
+					  0, init_once);
+	if (!btrfs_inode_cachep)
+		goto fail;
+	btrfs_trans_handle_cachep =
+			btrfs_cache_create("btrfs_trans_handle_cache",
+					   sizeof(struct btrfs_trans_handle),
+					   0, NULL);
+	if (!btrfs_trans_handle_cachep)
+		goto fail;
+	btrfs_transaction_cachep = btrfs_cache_create("btrfs_transaction_cache",
+					     sizeof(struct btrfs_transaction),
+					     0, NULL);
+	if (!btrfs_transaction_cachep)
+		goto fail;
+	btrfs_path_cachep = btrfs_cache_create("btrfs_path_cache",
+					 sizeof(struct btrfs_path),
+					 0, NULL);
+	if (!btrfs_path_cachep)
+		goto fail;
+	btrfs_bit_radix_cachep = btrfs_cache_create("btrfs_radix", 256,
+					      SLAB_DESTROY_BY_RCU, NULL);
+	if (!btrfs_bit_radix_cachep)
+		goto fail;
+	return 0;
+fail:
+	btrfs_destroy_cachep();
+	return -ENOMEM;
+}
+
+static int btrfs_getattr(struct vfsmount *mnt,
+			 struct dentry *dentry, struct kstat *stat)
+{
+	struct inode *inode = dentry->d_inode;
+	generic_fillattr(inode, stat);
+	stat->dev = BTRFS_I(inode)->root->anon_super.s_dev;
+	stat->blksize = PAGE_CACHE_SIZE;
+	stat->blocks = (inode_get_bytes(inode) +
+			BTRFS_I(inode)->delalloc_bytes) >> 9;
+	return 0;
+}
+
+static int btrfs_rename(struct inode *old_dir, struct dentry *old_dentry,
+			   struct inode *new_dir, struct dentry *new_dentry)
+{
+	struct btrfs_trans_handle *trans;
+	struct btrfs_root *root = BTRFS_I(old_dir)->root;
+	struct inode *new_inode = new_dentry->d_inode;
+	struct inode *old_inode = old_dentry->d_inode;
+	struct timespec ctime = CURRENT_TIME;
+	u64 index = 0;
+	int ret;
+
+	/* we're not allowed to rename between subvolumes */
+	if (BTRFS_I(old_inode)->root->root_key.objectid !=
+	    BTRFS_I(new_dir)->root->root_key.objectid)
+		return -EXDEV;
+
+	if (S_ISDIR(old_inode->i_mode) && new_inode &&
+	    new_inode->i_size > BTRFS_EMPTY_DIR_SIZE) {
+		return -ENOTEMPTY;
+	}
+
+	/* to rename a snapshot or subvolume, we need to juggle the
+	 * backrefs.  This isn't coded yet
+	 */
+	if (old_inode->i_ino == BTRFS_FIRST_FREE_OBJECTID)
+		return -EXDEV;
+
+	ret = btrfs_check_free_space(root, 1, 0);
+	if (ret)
+		goto out_unlock;
+
+	trans = btrfs_start_transaction(root, 1);
+
+	btrfs_set_trans_block_group(trans, new_dir);
+
+	btrfs_inc_nlink(old_dentry->d_inode);
+	old_dir->i_ctime = old_dir->i_mtime = ctime;
+	new_dir->i_ctime = new_dir->i_mtime = ctime;
+	old_inode->i_ctime = ctime;
+
+	ret = btrfs_unlink_inode(trans, root, old_dir, old_dentry->d_inode,
+				 old_dentry->d_name.name,
+				 old_dentry->d_name.len);
+	if (ret)
+		goto out_fail;
+
+	if (new_inode) {
+		new_inode->i_ctime = CURRENT_TIME;
+		ret = btrfs_unlink_inode(trans, root, new_dir,
+					 new_dentry->d_inode,
+					 new_dentry->d_name.name,
+					 new_dentry->d_name.len);
+		if (ret)
+			goto out_fail;
+		if (new_inode->i_nlink == 0) {
+			ret = btrfs_orphan_add(trans, new_dentry->d_inode);
+			if (ret)
+				goto out_fail;
+		}
+
+	}
+	ret = btrfs_set_inode_index(new_dir, &index);
+	if (ret)
+		goto out_fail;
+
+	ret = btrfs_add_link(trans, new_dentry->d_parent->d_inode,
+			     old_inode, new_dentry->d_name.name,
+			     new_dentry->d_name.len, 1, index);
+	if (ret)
+		goto out_fail;
+
+out_fail:
+	btrfs_end_transaction_throttle(trans, root);
+out_unlock:
+	return ret;
+}
+
+/*
+ * some fairly slow code that needs optimization. This walks the list
+ * of all the inodes with pending delalloc and forces them to disk.
+ */
+int btrfs_start_delalloc_inodes(struct btrfs_root *root)
+{
+	struct list_head *head = &root->fs_info->delalloc_inodes;
+	struct btrfs_inode *binode;
+	struct inode *inode;
+
+	if (root->fs_info->sb->s_flags & MS_RDONLY)
+		return -EROFS;
+
+	spin_lock(&root->fs_info->delalloc_lock);
+	while (!list_empty(head)) {
+		binode = list_entry(head->next, struct btrfs_inode,
+				    delalloc_inodes);
+		inode = igrab(&binode->vfs_inode);
+		if (!inode)
+			list_del_init(&binode->delalloc_inodes);
+		spin_unlock(&root->fs_info->delalloc_lock);
+		if (inode) {
+			filemap_flush(inode->i_mapping);
+			iput(inode);
+		}
+		cond_resched();
+		spin_lock(&root->fs_info->delalloc_lock);
+	}
+	spin_unlock(&root->fs_info->delalloc_lock);
+
+	/* the filemap_flush will queue IO into the worker threads, but
+	 * we have to make sure the IO is actually started and that
+	 * ordered extents get created before we return
+	 */
+	atomic_inc(&root->fs_info->async_submit_draining);
+	while (atomic_read(&root->fs_info->nr_async_submits) ||
+	      atomic_read(&root->fs_info->async_delalloc_pages)) {
+		wait_event(root->fs_info->async_submit_wait,
+		   (atomic_read(&root->fs_info->nr_async_submits) == 0 &&
+		    atomic_read(&root->fs_info->async_delalloc_pages) == 0));
+	}
+	atomic_dec(&root->fs_info->async_submit_draining);
+	return 0;
+}
+
+static int btrfs_symlink(struct inode *dir, struct dentry *dentry,
+			 const char *symname)
+{
+	struct btrfs_trans_handle *trans;
+	struct btrfs_root *root = BTRFS_I(dir)->root;
+	struct btrfs_path *path;
+	struct btrfs_key key;
+	struct inode *inode = NULL;
+	int err;
+	int drop_inode = 0;
+	u64 objectid;
+	u64 index = 0 ;
+	int name_len;
+	int datasize;
+	unsigned long ptr;
+	struct btrfs_file_extent_item *ei;
+	struct extent_buffer *leaf;
+	unsigned long nr = 0;
+
+	name_len = strlen(symname) + 1;
+	if (name_len > BTRFS_MAX_INLINE_DATA_SIZE(root))
+		return -ENAMETOOLONG;
+
+	err = btrfs_check_free_space(root, 1, 0);
+	if (err)
+		goto out_fail;
+
+	trans = btrfs_start_transaction(root, 1);
+	btrfs_set_trans_block_group(trans, dir);
+
+	err = btrfs_find_free_objectid(trans, root, dir->i_ino, &objectid);
+	if (err) {
+		err = -ENOSPC;
+		goto out_unlock;
+	}
+
+	inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
+				dentry->d_name.len,
+				dentry->d_parent->d_inode->i_ino, objectid,
+				BTRFS_I(dir)->block_group, S_IFLNK|S_IRWXUGO,
+				&index);
+	err = PTR_ERR(inode);
+	if (IS_ERR(inode))
+		goto out_unlock;
+
+	err = btrfs_init_acl(inode, dir);
+	if (err) {
+		drop_inode = 1;
+		goto out_unlock;
+	}
+
+	btrfs_set_trans_block_group(trans, inode);
+	err = btrfs_add_nondir(trans, dentry, inode, 0, index);
+	if (err)
+		drop_inode = 1;
+	else {
+		inode->i_mapping->a_ops = &btrfs_aops;
+		inode->i_mapping->backing_dev_info = &root->fs_info->bdi;
+		inode->i_fop = &btrfs_file_operations;
+		inode->i_op = &btrfs_file_inode_operations;
+		BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
+	}
+	dir->i_sb->s_dirt = 1;
+	btrfs_update_inode_block_group(trans, inode);
+	btrfs_update_inode_block_group(trans, dir);
+	if (drop_inode)
+		goto out_unlock;
+
+	path = btrfs_alloc_path();
+	BUG_ON(!path);
+	key.objectid = inode->i_ino;
+	key.offset = 0;
+	btrfs_set_key_type(&key, BTRFS_EXTENT_DATA_KEY);
+	datasize = btrfs_file_extent_calc_inline_size(name_len);
+	err = btrfs_insert_empty_item(trans, root, path, &key,
+				      datasize);
+	if (err) {
+		drop_inode = 1;
+		goto out_unlock;
+	}
+	leaf = path->nodes[0];
+	ei = btrfs_item_ptr(leaf, path->slots[0],
+			    struct btrfs_file_extent_item);
+	btrfs_set_file_extent_generation(leaf, ei, trans->transid);
+	btrfs_set_file_extent_type(leaf, ei,
+				   BTRFS_FILE_EXTENT_INLINE);
+	btrfs_set_file_extent_encryption(leaf, ei, 0);
+	btrfs_set_file_extent_compression(leaf, ei, 0);
+	btrfs_set_file_extent_other_encoding(leaf, ei, 0);
+	btrfs_set_file_extent_ram_bytes(leaf, ei, name_len);
+
+	ptr = btrfs_file_extent_inline_start(ei);
+	write_extent_buffer(leaf, symname, ptr, name_len);
+	btrfs_mark_buffer_dirty(leaf);
+	btrfs_free_path(path);
+
+	inode->i_op = &btrfs_symlink_inode_operations;
+	inode->i_mapping->a_ops = &btrfs_symlink_aops;
+	inode->i_mapping->backing_dev_info = &root->fs_info->bdi;
+	inode_set_bytes(inode, name_len);
+	btrfs_i_size_write(inode, name_len - 1);
+	err = btrfs_update_inode(trans, root, inode);
+	if (err)
+		drop_inode = 1;
+
+out_unlock:
+	nr = trans->blocks_used;
+	btrfs_end_transaction_throttle(trans, root);
+out_fail:
+	if (drop_inode) {
+		inode_dec_link_count(inode);
+		iput(inode);
+	}
+	btrfs_btree_balance_dirty(root, nr);
+	return err;
+}
+
+static int prealloc_file_range(struct inode *inode, u64 start, u64 end,
+			       u64 alloc_hint, int mode)
+{
+	struct btrfs_trans_handle *trans;
+	struct btrfs_root *root = BTRFS_I(inode)->root;
+	struct btrfs_key ins;
+	u64 alloc_size;
+	u64 cur_offset = start;
+	u64 num_bytes = end - start;
+	int ret = 0;
+
+	trans = btrfs_join_transaction(root, 1);
+	BUG_ON(!trans);
+	btrfs_set_trans_block_group(trans, inode);
+
+	while (num_bytes > 0) {
+		alloc_size = min(num_bytes, root->fs_info->max_extent);
+		ret = btrfs_reserve_extent(trans, root, alloc_size,
+					   root->sectorsize, 0, alloc_hint,
+					   (u64)-1, &ins, 1);
+		if (ret) {
+			WARN_ON(1);
+			goto out;
+		}
+		ret = insert_reserved_file_extent(trans, inode,
+						  cur_offset, ins.objectid,
+						  ins.offset, ins.offset,
+						  ins.offset, 0, 0, 0,
+						  BTRFS_FILE_EXTENT_PREALLOC);
+		BUG_ON(ret);
+		num_bytes -= ins.offset;
+		cur_offset += ins.offset;
+		alloc_hint = ins.objectid + ins.offset;
+	}
+out:
+	if (cur_offset > start) {
+		inode->i_ctime = CURRENT_TIME;
+		btrfs_set_flag(inode, PREALLOC);
+		if (!(mode & FALLOC_FL_KEEP_SIZE) &&
+		    cur_offset > i_size_read(inode))
+			btrfs_i_size_write(inode, cur_offset);
+		ret = btrfs_update_inode(trans, root, inode);
+		BUG_ON(ret);
+	}
+
+	btrfs_end_transaction(trans, root);
+	return ret;
+}
+
+static long btrfs_fallocate(struct inode *inode, int mode,
+			    loff_t offset, loff_t len)
+{
+	u64 cur_offset;
+	u64 last_byte;
+	u64 alloc_start;
+	u64 alloc_end;
+	u64 alloc_hint = 0;
+	u64 mask = BTRFS_I(inode)->root->sectorsize - 1;
+	struct extent_map *em;
+	int ret;
+
+	alloc_start = offset & ~mask;
+	alloc_end =  (offset + len + mask) & ~mask;
+
+	mutex_lock(&inode->i_mutex);
+	if (alloc_start > inode->i_size) {
+		ret = btrfs_cont_expand(inode, alloc_start);
+		if (ret)
+			goto out;
+	}
+
+	while (1) {
+		struct btrfs_ordered_extent *ordered;
+		lock_extent(&BTRFS_I(inode)->io_tree, alloc_start,
+			    alloc_end - 1, GFP_NOFS);
+		ordered = btrfs_lookup_first_ordered_extent(inode,
+							    alloc_end - 1);
+		if (ordered &&
+		    ordered->file_offset + ordered->len > alloc_start &&
+		    ordered->file_offset < alloc_end) {
+			btrfs_put_ordered_extent(ordered);
+			unlock_extent(&BTRFS_I(inode)->io_tree,
+				      alloc_start, alloc_end - 1, GFP_NOFS);
+			btrfs_wait_ordered_range(inode, alloc_start,
+						 alloc_end - alloc_start);
+		} else {
+			if (ordered)
+				btrfs_put_ordered_extent(ordered);
+			break;
+		}
+	}
+
+	cur_offset = alloc_start;
+	while (1) {
+		em = btrfs_get_extent(inode, NULL, 0, cur_offset,
+				      alloc_end - cur_offset, 0);
+		BUG_ON(IS_ERR(em) || !em);
+		last_byte = min(extent_map_end(em), alloc_end);
+		last_byte = (last_byte + mask) & ~mask;
+		if (em->block_start == EXTENT_MAP_HOLE) {
+			ret = prealloc_file_range(inode, cur_offset,
+					last_byte, alloc_hint, mode);
+			if (ret < 0) {
+				free_extent_map(em);
+				break;
+			}
+		}
+		if (em->block_start <= EXTENT_MAP_LAST_BYTE)
+			alloc_hint = em->block_start;
+		free_extent_map(em);
+
+		cur_offset = last_byte;
+		if (cur_offset >= alloc_end) {
+			ret = 0;
+			break;
+		}
+	}
+	unlock_extent(&BTRFS_I(inode)->io_tree, alloc_start, alloc_end - 1,
+		      GFP_NOFS);
+out:
+	mutex_unlock(&inode->i_mutex);
+	return ret;
+}
+
+static int btrfs_set_page_dirty(struct page *page)
+{
+	return __set_page_dirty_nobuffers(page);
+}
+
+static int btrfs_permission(struct inode *inode, int mask)
+{
+	if (btrfs_test_flag(inode, READONLY) && (mask & MAY_WRITE))
+		return -EACCES;
+	return generic_permission(inode, mask, btrfs_check_acl);
+}
+
+static struct inode_operations btrfs_dir_inode_operations = {
+	.getattr	= btrfs_getattr,
+	.lookup		= btrfs_lookup,
+	.create		= btrfs_create,
+	.unlink		= btrfs_unlink,
+	.link		= btrfs_link,
+	.mkdir		= btrfs_mkdir,
+	.rmdir		= btrfs_rmdir,
+	.rename		= btrfs_rename,
+	.symlink	= btrfs_symlink,
+	.setattr	= btrfs_setattr,
+	.mknod		= btrfs_mknod,
+	.setxattr	= btrfs_setxattr,
+	.getxattr	= btrfs_getxattr,
+	.listxattr	= btrfs_listxattr,
+	.removexattr	= btrfs_removexattr,
+	.permission	= btrfs_permission,
+};
+static struct inode_operations btrfs_dir_ro_inode_operations = {
+	.lookup		= btrfs_lookup,
+	.permission	= btrfs_permission,
+};
+static struct file_operations btrfs_dir_file_operations = {
+	.llseek		= generic_file_llseek,
+	.read		= generic_read_dir,
+	.readdir	= btrfs_real_readdir,
+	.unlocked_ioctl	= btrfs_ioctl,
+#ifdef CONFIG_COMPAT
+	.compat_ioctl	= btrfs_ioctl,
+#endif
+	.release        = btrfs_release_file,
+	.fsync		= btrfs_sync_file,
+};
+
+static struct address_space_operations btrfs_aops = {
+	.readpage	= btrfs_readpage,
+	.writepage	= btrfs_writepage,
+	.writepages	= btrfs_writepages,
+	.readpages	= btrfs_readpages,
+	.sync_page	= block_sync_page,
+	.bmap		= btrfs_bmap,
+	.direct_IO	= btrfs_direct_IO,
+	.invalidatepage = btrfs_invalidatepage,
+	.releasepage	= btrfs_releasepage,
+	.set_page_dirty	= btrfs_set_page_dirty,
+};
+
+static struct address_space_operations btrfs_symlink_aops = {
+	.readpage	= btrfs_readpage,
+	.writepage	= btrfs_writepage,
+	.invalidatepage = btrfs_invalidatepage,
+	.releasepage	= btrfs_releasepage,
+};
+
+static struct inode_operations btrfs_file_inode_operations = {
+	.truncate	= btrfs_truncate,
+	.getattr	= btrfs_getattr,
+	.setattr	= btrfs_setattr,
+	.setxattr	= btrfs_setxattr,
+	.getxattr	= btrfs_getxattr,
+	.listxattr      = btrfs_listxattr,
+	.removexattr	= btrfs_removexattr,
+	.permission	= btrfs_permission,
+	.fallocate	= btrfs_fallocate,
+};
+static struct inode_operations btrfs_special_inode_operations = {
+	.getattr	= btrfs_getattr,
+	.setattr	= btrfs_setattr,
+	.permission	= btrfs_permission,
+	.setxattr	= btrfs_setxattr,
+	.getxattr	= btrfs_getxattr,
+	.listxattr	= btrfs_listxattr,
+	.removexattr	= btrfs_removexattr,
+};
+static struct inode_operations btrfs_symlink_inode_operations = {
+	.readlink	= generic_readlink,
+	.follow_link	= page_follow_link_light,
+	.put_link	= page_put_link,
+	.permission	= btrfs_permission,
+};


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