Merge branch 'master' into next

Conflicts:
	fs/namei.c

Manually merged per:

diff --cc fs/namei.c
index 734f2b5,bbc15c2..0000000
--- a/fs/namei.c
+++ b/fs/namei.c
@@@ -860,9 -848,8 +849,10 @@@ static int __link_path_walk(const char
  		nd->flags |= LOOKUP_CONTINUE;
  		err = exec_permission_lite(inode);
  		if (err == -EAGAIN)
- 			err = vfs_permission(nd, MAY_EXEC);
+ 			err = inode_permission(nd->path.dentry->d_inode,
+ 					       MAY_EXEC);
 +		if (!err)
 +			err = ima_path_check(&nd->path, MAY_EXEC);
   		if (err)
  			break;

@@@ -1525,14 -1506,9 +1509,14 @@@ int may_open(struct path *path, int acc
  		flag &= ~O_TRUNC;
  	}

- 	error = vfs_permission(nd, acc_mode);
+ 	error = inode_permission(inode, acc_mode);
  	if (error)
  		return error;
 +
- 	error = ima_path_check(&nd->path,
++	error = ima_path_check(path,
 +			       acc_mode & (MAY_READ | MAY_WRITE | MAY_EXEC));
 +	if (error)
 +		return error;
  	/*
  	 * An append-only file must be opened in append mode for writing.
  	 */

Signed-off-by: James Morris <jmorris@namei.org>

1 files changed, 5035 insertions, 0 deletions

diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
new file mode 100644
index 0000000..8adfe05
--- /dev/null
+++ b/fs/btrfs/inode.c
@@ -0,0 +1,5035 @@
+/*
+ * 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 int btrfs_finish_ordered_io(struct inode *inode, u64 start, u64 end);
+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;
+}
+
+/*
+ * this does all the hard work for inserting an inline extent into
+ * the btree.  The caller should have done a btrfs_drop_extents so that
+ * no overlapping inline items exist in the btree
+ */
+static noinline int insert_inline_extent(struct btrfs_trans_handle *trans,
+				struct btrfs_root *root, struct inode *inode,
+				u64 start, size_t size, size_t compressed_size,
+				struct page **compressed_pages)
+{
+	struct btrfs_key key;
+	struct btrfs_path *path;
+	struct extent_buffer *leaf;
+	struct page *page = NULL;
+	char *kaddr;
+	unsigned long ptr;
+	struct btrfs_file_extent_item *ei;
+	int err = 0;
+	int ret;
+	size_t cur_size = size;
+	size_t datasize;
+	unsigned long offset;
+	int use_compress = 0;
+
+	if (compressed_size && compressed_pages) {
+		use_compress = 1;
+		cur_size = compressed_size;
+	}
+
+	path = btrfs_alloc_path();
+	if (!path)
+		return -ENOMEM;
+
+	btrfs_set_trans_block_group(trans, inode);
+
+	key.objectid = inode->i_ino;
+	key.offset = start;
+	btrfs_set_key_type(&key, BTRFS_EXTENT_DATA_KEY);
+	datasize = btrfs_file_extent_calc_inline_size(cur_size);
+
+	inode_add_bytes(inode, size);
+	ret = btrfs_insert_empty_item(trans, root, path, &key,
+				      datasize);
+	BUG_ON(ret);
+	if (ret) {
+		err = ret;
+		goto fail;
+	}
+	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_other_encoding(leaf, ei, 0);
+	btrfs_set_file_extent_ram_bytes(leaf, ei, size);
+	ptr = btrfs_file_extent_inline_start(ei);
+
+	if (use_compress) {
+		struct page *cpage;
+		int i = 0;
+		while (compressed_size > 0) {
+			cpage = compressed_pages[i];
+			cur_size = min_t(unsigned long, compressed_size,
+				       PAGE_CACHE_SIZE);
+
+			kaddr = kmap(cpage);
+			write_extent_buffer(leaf, kaddr, ptr, cur_size);
+			kunmap(cpage);
+
+			i++;
+			ptr += cur_size;
+			compressed_size -= cur_size;
+		}
+		btrfs_set_file_extent_compression(leaf, ei,
+						  BTRFS_COMPRESS_ZLIB);
+	} else {
+		page = find_get_page(inode->i_mapping,
+				     start >> PAGE_CACHE_SHIFT);
+		btrfs_set_file_extent_compression(leaf, ei, 0);
+		kaddr = kmap_atomic(page, KM_USER0);
+		offset = start & (PAGE_CACHE_SIZE - 1);
+		write_extent_buffer(leaf, kaddr + offset, ptr, size);
+		kunmap_atomic(kaddr, KM_USER0);
+		page_cache_release(page);
+	}
+	btrfs_mark_buffer_dirty(leaf);
+	btrfs_free_path(path);
+
+	BTRFS_I(inode)->disk_i_size = inode->i_size;
+	btrfs_update_inode(trans, root, inode);
+	return 0;
+fail:
+	btrfs_free_path(path);
+	return err;
+}
+
+
+/*
+ * conditionally insert an inline extent into the file.  This
+ * does the checks required to make sure the data is small enough
+ * to fit as an inline extent.
+ */
+static int cow_file_range_inline(struct btrfs_trans_handle *trans,
+				 struct btrfs_root *root,
+				 struct inode *inode, u64 start, u64 end,
+				 size_t compressed_size,
+				 struct page **compressed_pages)
+{
+	u64 isize = i_size_read(inode);
+	u64 actual_end = min(end + 1, isize);
+	u64 inline_len = actual_end - start;
+	u64 aligned_end = (end + root->sectorsize - 1) &
+			~((u64)root->sectorsize - 1);
+	u64 hint_byte;
+	u64 data_len = inline_len;
+	int ret;
+
+	if (compressed_size)
+		data_len = compressed_size;
+
+	if (start > 0 ||
+	    actual_end >= PAGE_CACHE_SIZE ||
+	    data_len >= BTRFS_MAX_INLINE_DATA_SIZE(root) ||
+	    (!compressed_size &&
+	    (actual_end & (root->sectorsize - 1)) == 0) ||
+	    end + 1 < isize ||
+	    data_len > root->fs_info->max_inline) {
+		return 1;
+	}
+
+	ret = btrfs_drop_extents(trans, root, inode, start,
+				 aligned_end, start, &hint_byte);
+	BUG_ON(ret);
+
+	if (isize > actual_end)
+		inline_len = min_t(u64, isize, actual_end);
+	ret = insert_inline_extent(trans, root, inode, start,
+				   inline_len, compressed_size,
+				   compressed_pages);
+	BUG_ON(ret);
+	btrfs_drop_extent_cache(inode, start, aligned_end, 0);
+	return 0;
+}
+
+struct async_extent {
+	u64 start;
+	u64 ram_size;
+	u64 compressed_size;
+	struct page **pages;
+	unsigned long nr_pages;
+	struct list_head list;
+};
+
+struct async_cow {
+	struct inode *inode;
+	struct btrfs_root *root;
+	struct page *locked_page;
+	u64 start;
+	u64 end;
+	struct list_head extents;
+	struct btrfs_work work;
+};
+
+static noinline int add_async_extent(struct async_cow *cow,
+				     u64 start, u64 ram_size,
+				     u64 compressed_size,
+				     struct page **pages,
+				     unsigned long nr_pages)
+{
+	struct async_extent *async_extent;
+
+	async_extent = kmalloc(sizeof(*async_extent), GFP_NOFS);
+	async_extent->start = start;
+	async_extent->ram_size = ram_size;
+	async_extent->compressed_size = compressed_size;
+	async_extent->pages = pages;
+	async_extent->nr_pages = nr_pages;
+	list_add_tail(&async_extent->list, &cow->extents);
+	return 0;
+}
+
+/*
+ * we create compressed extents in two phases.  The first
+ * phase compresses a range of pages that have already been
+ * locked (both pages and state bits are locked).
+ *
+ * This is done inside an ordered work queue, and the compression
+ * is spread across many cpus.  The actual IO submission is step
+ * two, and the ordered work queue takes care of making sure that
+ * happens in the same order things were put onto the queue by
+ * writepages and friends.
+ *
+ * If this code finds it can't get good compression, it puts an
+ * entry onto the work queue to write the uncompressed bytes.  This
+ * makes sure that both compressed inodes and uncompressed inodes
+ * are written in the same order that pdflush sent them down.
+ */
+static noinline int compress_file_range(struct inode *inode,
+					struct page *locked_page,
+					u64 start, u64 end,
+					struct async_cow *async_cow,
+					int *num_added)
+{
+	struct btrfs_root *root = BTRFS_I(inode)->root;
+	struct btrfs_trans_handle *trans;
+	u64 num_bytes;
+	u64 orig_start;
+	u64 disk_num_bytes;
+	u64 blocksize = root->sectorsize;
+	u64 actual_end;
+	u64 isize = i_size_read(inode);
+	int ret = 0;
+	struct page **pages = NULL;
+	unsigned long nr_pages;
+	unsigned long nr_pages_ret = 0;
+	unsigned long total_compressed = 0;
+	unsigned long total_in = 0;
+	unsigned long max_compressed = 128 * 1024;
+	unsigned long max_uncompressed = 128 * 1024;
+	int i;
+	int will_compress;
+
+	orig_start = start;
+
+	actual_end = min_t(u64, isize, end + 1);
+again:
+	will_compress = 0;
+	nr_pages = (end >> PAGE_CACHE_SHIFT) - (start >> PAGE_CACHE_SHIFT) + 1;
+	nr_pages = min(nr_pages, (128 * 1024UL) / PAGE_CACHE_SIZE);
+
+	total_compressed = actual_end - start;
+
+	/* we want to make sure that amount of ram required to uncompress
+	 * an extent is reasonable, so we limit the total size in ram
+	 * of a compressed extent to 128k.  This is a crucial number
+	 * because it also controls how easily we can spread reads across
+	 * cpus for decompression.
+	 *
+	 * We also want to make sure the amount of IO required to do
+	 * a random read is reasonably small, so we limit the size of
+	 * a compressed extent to 128k.
+	 */
+	total_compressed = min(total_compressed, max_uncompressed);
+	num_bytes = (end - start + blocksize) & ~(blocksize - 1);
+	num_bytes = max(blocksize,  num_bytes);
+	disk_num_bytes = num_bytes;
+	total_in = 0;
+	ret = 0;
+
+	/*
+	 * we do compression for mount -o compress and when the
+	 * inode has not been flagged as nocompress.  This flag can
+	 * change at any time if we discover bad compression ratios.
+	 */
+	if (!btrfs_test_flag(inode, NOCOMPRESS) &&
+	    btrfs_test_opt(root, COMPRESS)) {
+		WARN_ON(pages);
+		pages = kzalloc(sizeof(struct page *) * nr_pages, GFP_NOFS);
+
+		ret = btrfs_zlib_compress_pages(inode->i_mapping, start,
+						total_compressed, pages,
+						nr_pages, &nr_pages_ret,
+						&total_in,
+						&total_compressed,
+						max_compressed);
+
+		if (!ret) {
+			unsigned long offset = total_compressed &
+				(PAGE_CACHE_SIZE - 1);
+			struct page *page = pages[nr_pages_ret - 1];
+			char *kaddr;
+
+			/* zero the tail end of the last page, we might be
+			 * sending it down to disk
+			 */
+			if (offset) {
+				kaddr = kmap_atomic(page, KM_USER0);
+				memset(kaddr + offset, 0,
+				       PAGE_CACHE_SIZE - offset);
+				kunmap_atomic(kaddr, KM_USER0);
+			}
+			will_compress = 1;
+		}
+	}
+	if (start == 0) {
+		trans = btrfs_join_transaction(root, 1);
+		BUG_ON(!trans);
+		btrfs_set_trans_block_group(trans, inode);
+
+		/* lets try to make an inline extent */
+		if (ret || total_in < (actual_end - start)) {
+			/* we didn't compress the entire range, try
+			 * to make an uncompressed inline extent.
+			 */
+			ret = cow_file_range_inline(trans, root, inode,
+						    start, end, 0, NULL);
+		} else {
+			/* try making a compressed inline extent */
+			ret = cow_file_range_inline(trans, root, inode,
+						    start, end,
+						    total_compressed, pages);
+		}
+		btrfs_end_transaction(trans, root);
+		if (ret == 0) {
+			/*
+			 * inline extent creation worked, we don't need
+			 * to create any more async work items.  Unlock
+			 * and free up our temp pages.
+			 */
+			extent_clear_unlock_delalloc(inode,
+						     &BTRFS_I(inode)->io_tree,
+						     start, end, NULL, 1, 0,
+						     0, 1, 1, 1);
+			ret = 0;
+			goto free_pages_out;
+		}
+	}
+
+	if (will_compress) {
+		/*
+		 * we aren't doing an inline extent round the compressed size
+		 * up to a block size boundary so the allocator does sane
+		 * things
+		 */
+		total_compressed = (total_compressed + blocksize - 1) &
+			~(blocksize - 1);
+
+		/*
+		 * one last check to make sure the compression is really a
+		 * win, compare the page count read with the blocks on disk
+		 */
+		total_in = (total_in + PAGE_CACHE_SIZE - 1) &
+			~(PAGE_CACHE_SIZE - 1);
+		if (total_compressed >= total_in) {
+			will_compress = 0;
+		} else {
+			disk_num_bytes = total_compressed;
+			num_bytes = total_in;
+		}
+	}
+	if (!will_compress && pages) {
+		/*
+		 * the compression code ran but failed to make things smaller,
+		 * free any pages it allocated and our page pointer array
+		 */
+		for (i = 0; i < nr_pages_ret; i++) {
+			WARN_ON(pages[i]->mapping);
+			page_cache_release(pages[i]);
+		}
+		kfree(pages);
+		pages = NULL;
+		total_compressed = 0;
+		nr_pages_ret = 0;
+
+		/* flag the file so we don't compress in the future */
+		btrfs_set_flag(inode, NOCOMPRESS);
+	}
+	if (will_compress) {
+		*num_added += 1;
+
+		/* the async work queues will take care of doing actual
+		 * allocation on disk for these compressed pages,
+		 * and will submit them to the elevator.
+		 */
+		add_async_extent(async_cow, start, num_bytes,
+				 total_compressed, pages, nr_pages_ret);
+
+		if (start + num_bytes < end && start + num_bytes < actual_end) {
+			start += num_bytes;
+			pages = NULL;
+			cond_resched();
+			goto again;
+		}
+	} else {
+		/*
+		 * No compression, but we still need to write the pages in
+		 * the file we've been given so far.  redirty the locked
+		 * page if it corresponds to our extent and set things up
+		 * for the async work queue to run cow_file_range to do
+		 * the normal delalloc dance
+		 */
+		if (page_offset(locked_page) >= start &&
+		    page_offset(locked_page) <= end) {
+			__set_page_dirty_nobuffers(locked_page);
+			/* unlocked later on in the async handlers */
+		}
+		add_async_extent(async_cow, start, end - start + 1, 0, NULL, 0);
+		*num_added += 1;
+	}
+
+out:
+	return 0;
+
+free_pages_out:
+	for (i = 0; i < nr_pages_ret; i++) {
+		WARN_ON(pages[i]->mapping);
+		page_cache_release(pages[i]);
+	}
+	kfree(pages);
+
+	goto out;
+}
+
+/*
+ * phase two of compressed writeback.  This is the ordered portion
+ * of the code, which only gets called in the order the work was
+ * queued.  We walk all the async extents created by compress_file_range
+ * and send them down to the disk.
+ */
+static noinline int submit_compressed_extents(struct inode *inode,
+					      struct async_cow *async_cow)
+{
+	struct async_extent *async_extent;
+	u64 alloc_hint = 0;
+	struct btrfs_trans_handle *trans;
+	struct btrfs_key ins;
+	struct extent_map *em;
+	struct btrfs_root *root = BTRFS_I(inode)->root;
+	struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
+	struct extent_io_tree *io_tree;
+	int ret;
+
+	if (list_empty(&async_cow->extents))
+		return 0;
+
+	trans = btrfs_join_transaction(root, 1);
+
+	while (!list_empty(&async_cow->extents)) {
+		async_extent = list_entry(async_cow->extents.next,
+					  struct async_extent, list);
+		list_del(&async_extent->list);
+
+		io_tree = &BTRFS_I(inode)->io_tree;
+
+		/* did the compression code fall back to uncompressed IO? */
+		if (!async_extent->pages) {
+			int page_started = 0;
+			unsigned long nr_written = 0;
+
+			lock_extent(io_tree, async_extent->start,
+				    async_extent->start +
+				    async_extent->ram_size - 1, GFP_NOFS);
+
+			/* allocate blocks */
+			cow_file_range(inode, async_cow->locked_page,
+				       async_extent->start,
+				       async_extent->start +
+				       async_extent->ram_size - 1,
+				       &page_started, &nr_written, 0);
+
+			/*
+			 * if page_started, cow_file_range inserted an
+			 * inline extent and took care of all the unlocking
+			 * and IO for us.  Otherwise, we need to submit
+			 * all those pages down to the drive.
+			 */
+			if (!page_started)
+				extent_write_locked_range(io_tree,
+						  inode, async_extent->start,
+						  async_extent->start +
+						  async_extent->ram_size - 1,
+						  btrfs_get_extent,
+						  WB_SYNC_ALL);
+			kfree(async_extent);
+			cond_resched();
+			continue;
+		}
+
+		lock_extent(io_tree, async_extent->start,
+			    async_extent->start + async_extent->ram_size - 1,
+			    GFP_NOFS);
+		/*
+		 * here we're doing allocation and writeback of the
+		 * compressed pages
+		 */
+		btrfs_drop_extent_cache(inode, async_extent->start,
+					async_extent->start +
+					async_extent->ram_size - 1, 0);
+
+		ret = btrfs_reserve_extent(trans, root,
+					   async_extent->compressed_size,
+					   async_extent->compressed_size,
+					   0, alloc_hint,
+					   (u64)-1, &ins, 1);
+		BUG_ON(ret);
+		em = alloc_extent_map(GFP_NOFS);
+		em->start = async_extent->start;
+		em->len = async_extent->ram_size;
+		em->orig_start = em->start;
+
+		em->block_start = ins.objectid;
+		em->block_len = ins.offset;
+		em->bdev = root->fs_info->fs_devices->latest_bdev;
+		set_bit(EXTENT_FLAG_PINNED, &em->flags);
+		set_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
+
+		while (1) {
+			spin_lock(&em_tree->lock);
+			ret = add_extent_mapping(em_tree, em);
+			spin_unlock(&em_tree->lock);
+			if (ret != -EEXIST) {
+				free_extent_map(em);
+				break;
+			}
+			btrfs_drop_extent_cache(inode, async_extent->start,
+						async_extent->start +
+						async_extent->ram_size - 1, 0);
+		}
+
+		ret = btrfs_add_ordered_extent(inode, async_extent->start,
+					       ins.objectid,
+					       async_extent->ram_size,
+					       ins.offset,
+					       BTRFS_ORDERED_COMPRESSED);
+		BUG_ON(ret);
+
+		btrfs_end_transaction(trans, root);
+
+		/*
+		 * clear dirty, set writeback and unlock the pages.
+		 */
+		extent_clear_unlock_delalloc(inode,
+					     &BTRFS_I(inode)->io_tree,
+					     async_extent->start,
+					     async_extent->start +
+					     async_extent->ram_size - 1,
+					     NULL, 1, 1, 0, 1, 1, 0);
+
+		ret = btrfs_submit_compressed_write(inode,
+				    async_extent->start,
+				    async_extent->ram_size,
+				    ins.objectid,
+				    ins.offset, async_extent->pages,
+				    async_extent->nr_pages);
+
+		BUG_ON(ret);
+		trans = btrfs_join_transaction(root, 1);
+		alloc_hint = ins.objectid + ins.offset;
+		kfree(async_extent);
+		cond_resched();
+	}
+
+	btrfs_end_transaction(trans, root);
+	return 0;
+}
+
+/*
+ * when extent_io.c finds a delayed allocation range in the file,
+ * the call backs end up in this code.  The basic idea is to
+ * allocate extents on disk for the range, and create ordered data structs
+ * in ram to track those extents.
+ *
+ * locked_page is the page that writepage had locked already.  We use
+ * it to make sure we don't do extra locks or unlocks.
+ *
+ * *page_started is set to one if we unlock locked_page and do everything
+ * required to start IO on it.  It may be clean and already done with
+ * IO when we return.
+ */
+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)
+{
+	struct btrfs_root *root = BTRFS_I(inode)->root;
+	struct btrfs_trans_handle *trans;
+	u64 alloc_hint = 0;
+	u64 num_bytes;
+	unsigned long ram_size;
+	u64 disk_num_bytes;
+	u64 cur_alloc_size;
+	u64 blocksize = root->sectorsize;
+	u64 actual_end;
+	u64 isize = i_size_read(inode);
+	struct btrfs_key ins;
+	struct extent_map *em;
+	struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
+	int ret = 0;
+
+	trans = btrfs_join_transaction(root, 1);
+	BUG_ON(!trans);
+	btrfs_set_trans_block_group(trans, inode);
+
+	actual_end = min_t(u64, isize, end + 1);
+
+	num_bytes = (end - start + blocksize) & ~(blocksize - 1);
+	num_bytes = max(blocksize,  num_bytes);
+	disk_num_bytes = num_bytes;
+	ret = 0;
+
+	if (start == 0) {
+		/* lets try to make an inline extent */
+		ret = cow_file_range_inline(trans, root, inode,
+					    start, end, 0, NULL);
+		if (ret == 0) {
+			extent_clear_unlock_delalloc(inode,
+						     &BTRFS_I(inode)->io_tree,
+						     start, end, NULL, 1, 1,
+						     1, 1, 1, 1);
+			*nr_written = *nr_written +
+			     (end - start + PAGE_CACHE_SIZE) / PAGE_CACHE_SIZE;
+			*page_started = 1;
+			ret = 0;
+			goto out;
+		}
+	}
+
+	BUG_ON(disk_num_bytes >
+	       btrfs_super_total_bytes(&root->fs_info->super_copy));
+
+	btrfs_drop_extent_cache(inode, start, start + num_bytes - 1, 0);
+
+	while (disk_num_bytes > 0) {
+		cur_alloc_size = min(disk_num_bytes, root->fs_info->max_extent);
+		ret = btrfs_reserve_extent(trans, root, cur_alloc_size,
+					   root->sectorsize, 0, alloc_hint,
+					   (u64)-1, &ins, 1);
+		BUG_ON(ret);
+
+		em = alloc_extent_map(GFP_NOFS);
+		em->start = start;
+		em->orig_start = em->start;
+
+		ram_size = ins.offset;
+		em->len = ins.offset;
+
+		em->block_start = ins.objectid;
+		em->block_len = ins.offset;
+		em->bdev = root->fs_info->fs_devices->latest_bdev;
+		set_bit(EXTENT_FLAG_PINNED, &em->flags);
+
+		while (1) {
+			spin_lock(&em_tree->lock);
+			ret = add_extent_mapping(em_tree, em);
+			spin_unlock(&em_tree->lock);
+			if (ret != -EEXIST) {
+				free_extent_map(em);
+				break;
+			}
+			btrfs_drop_extent_cache(inode, start,
+						start + ram_size - 1, 0);
+		}
+
+		cur_alloc_size = ins.offset;
+		ret = btrfs_add_ordered_extent(inode, start, ins.objectid,
+					       ram_size, cur_alloc_size, 0);
+		BUG_ON(ret);
+
+		if (root->root_key.objectid ==
+		    BTRFS_DATA_RELOC_TREE_OBJECTID) {
+			ret = btrfs_reloc_clone_csums(inode, start,
+						      cur_alloc_size);
+			BUG_ON(ret);
+		}
+
+		if (disk_num_bytes < cur_alloc_size)
+			break;
+
+		/* we're not doing compressed IO, don't unlock the first
+		 * page (which the caller expects to stay locked), don't
+		 * clear any dirty bits and don't set any writeback bits
+		 */
+		extent_clear_unlock_delalloc(inode, &BTRFS_I(inode)->io_tree,
+					     start, start + ram_size - 1,
+					     locked_page, unlock, 1,
+					     1, 0, 0, 0);
+		disk_num_bytes -= cur_alloc_size;
+		num_bytes -= cur_alloc_size;
+		alloc_hint = ins.objectid + ins.offset;
+		start += cur_alloc_size;
+	}
+out:
+	ret = 0;
+	btrfs_end_transaction(trans, root);
+
+	return ret;
+}
+
+/*
+ * work queue call back to started compression on a file and pages
+ */
+static noinline void async_cow_start(struct btrfs_work *work)
+{
+	struct async_cow *async_cow;
+	int num_added = 0;
+	async_cow = container_of(work, struct async_cow, work);
+
+	compress_file_range(async_cow->inode, async_cow->locked_page,
+			    async_cow->start, async_cow->end, async_cow,
+			    &num_added);
+	if (num_added == 0)
+		async_cow->inode = NULL;
+}
+
+/*
+ * work queue call back to submit previously compressed pages
+ */
+static noinline void async_cow_submit(struct btrfs_work *work)
+{
+	struct async_cow *async_cow;
+	struct btrfs_root *root;
+	unsigned long nr_pages;
+
+	async_cow = container_of(work, struct async_cow, work);
+
+	root = async_cow->root;
+	nr_pages = (async_cow->end - async_cow->start + PAGE_CACHE_SIZE) >>
+		PAGE_CACHE_SHIFT;
+
+	atomic_sub(nr_pages, &root->fs_info->async_delalloc_pages);
+
+	if (atomic_read(&root->fs_info->async_delalloc_pages) <
+	    5 * 1042 * 1024 &&
+	    waitqueue_active(&root->fs_info->async_submit_wait))
+		wake_up(&root->fs_info->async_submit_wait);
+
+	if (async_cow->inode)
+		submit_compressed_extents(async_cow->inode, async_cow);
+}
+
+static noinline void async_cow_free(struct btrfs_work *work)
+{
+	struct async_cow *async_cow;
+	async_cow = container_of(work, struct async_cow, work);
+	kfree(async_cow);
+}
+
+static int cow_file_range_async(struct inode *inode, struct page *locked_page,
+				u64 start, u64 end, int *page_started,
+				unsigned long *nr_written)
+{
+	struct async_cow *async_cow;
+	struct btrfs_root *root = BTRFS_I(inode)->root;
+	unsigned long nr_pages;
+	u64 cur_end;
+	int limit = 10 * 1024 * 1042;
+
+	if (!btrfs_test_opt(root, COMPRESS)) {
+		return cow_file_range(inode, locked_page, start, end,
+				      page_started, nr_written, 1);
+	}
+
+	clear_extent_bit(&BTRFS_I(inode)->io_tree, start, end, EXTENT_LOCKED |
+			 EXTENT_DELALLOC, 1, 0, GFP_NOFS);
+	while (start < end) {
+		async_cow = kmalloc(sizeof(*async_cow), GFP_NOFS);
+		async_cow->inode = inode;
+		async_cow->root = root;
+		async_cow->locked_page = locked_page;
+		async_cow->start = start;
+
+		if (btrfs_test_flag(inode, NOCOMPRESS))
+			cur_end = end;
+		else
+			cur_end = min(end, start + 512 * 1024 - 1);
+
+		async_cow->end = cur_end;
+		INIT_LIST_HEAD(&async_cow->extents);
+
+		async_cow->work.func = async_cow_start;
+		async_cow->work.ordered_func = async_cow_submit;
+		async_cow->work.ordered_free = async_cow_free;
+		async_cow->work.flags = 0;
+
+		nr_pages = (cur_end - start + PAGE_CACHE_SIZE) >>
+			PAGE_CACHE_SHIFT;
+		atomic_add(nr_pages, &root->fs_info->async_delalloc_pages);
+
+		btrfs_queue_worker(&root->fs_info->delalloc_workers,
+				   &async_cow->work);
+
+		if (atomic_read(&root->fs_info->async_delalloc_pages) > limit) {
+			wait_event(root->fs_info->async_submit_wait,
+			   (atomic_read(&root->fs_info->async_delalloc_pages) <
+			    limit));
+		}
+
+		while (atomic_read(&root->fs_info->async_submit_draining) &&
+		      atomic_read(&root->fs_info->async_delalloc_pages)) {
+			wait_event(root->fs_info->async_submit_wait,
+			  (atomic_read(&root->fs_info->async_delalloc_pages) ==
+			   0));
+		}
+
+		*nr_written += nr_pages;
+		start = cur_end + 1;
+	}
+	*page_started = 1;
+	return 0;
+}
+
+static noinline int csum_exist_in_range(struct btrfs_root *root,
+					u64 bytenr, u64 num_bytes)
+{
+	int ret;
+	struct btrfs_ordered_sum *sums;
+	LIST_HEAD(list);
+
+	ret = btrfs_lookup_csums_range(root->fs_info->csum_root, bytenr,
+				       bytenr + num_bytes - 1, &list);
+	if (ret == 0 && list_empty(&list))
+		return 0;
+
+	while (!list_empty(&list)) {
+		sums = list_entry(list.next, struct btrfs_ordered_sum, list);
+		list_del(&sums->list);
+		kfree(sums);
+	}
+	return 1;
+}
+
+/*
+ * when nowcow writeback call back.  This checks for snapshots or COW copies
+ * of the extents that exist in the file, and COWs the file as required.
+ *
+ * If no cow copies or snapshots exist, we write directly to the existing
+ * blocks on disk
+ */
+static int run_delalloc_nocow(struct inode *inode, struct page *locked_page,
+			      u64 start, u64 end, int *page_started, int force,
+			      unsigned long *nr_written)
+{
+	struct btrfs_root *root = BTRFS_I(inode)->root;
+	struct btrfs_trans_handle *trans;
+	struct extent_buffer *leaf;
+	struct btrfs_path *path;
+	struct btrfs_file_extent_item *fi;
+	struct btrfs_key found_key;
+	u64 cow_start;
+	u64 cur_offset;
+	u64 extent_end;
+	u64 disk_bytenr;
+	u64 num_bytes;
+	int extent_type;
+	int ret;
+	int type;
+	int nocow;
+	int check_prev = 1;
+
+	path = btrfs_alloc_path();
+	BUG_ON(!path);
+	trans = btrfs_join_transaction(root, 1);
+	BUG_ON(!trans);
+
+	cow_start = (u64)-1;
+	cur_offset = start;
+	while (1) {
+		ret = btrfs_lookup_file_extent(trans, root, path, inode->i_ino,
+					       cur_offset, 0);
+		BUG_ON(ret < 0);
+		if (ret > 0 && path->slots[0] > 0 && check_prev) {
+			leaf = path->nodes[0];
+			btrfs_item_key_to_cpu(leaf, &found_key,
+					      path->slots[0] - 1);
+			if (found_key.objectid == inode->i_ino &&
+			    found_key.type == BTRFS_EXTENT_DATA_KEY)
+				path->slots[0]--;
+		}
+		check_prev = 0;
+next_slot:
+		leaf = path->nodes[0];
+		if (path->slots[0] >= btrfs_header_nritems(leaf)) {
+			ret = btrfs_next_leaf(root, path);
+			if (ret < 0)
+				BUG_ON(1);
+			if (ret > 0)
+				break;
+			leaf = path->nodes[0];
+		}
+
+		nocow = 0;
+		disk_bytenr = 0;
+		num_bytes = 0;
+		btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
+
+		if (found_key.objectid > inode->i_ino ||
+		    found_key.type > BTRFS_EXTENT_DATA_KEY ||
+		    found_key.offset > end)
+			break;
+
+		if (found_key.offset > cur_offset) {
+			extent_end = found_key.offset;
+			goto out_check;
+		}
+
+		fi = btrfs_item_ptr(leaf, path->slots[0],
+				    struct btrfs_file_extent_item);
+		extent_type = btrfs_file_extent_type(leaf, fi);
+
+		if (extent_type == BTRFS_FILE_EXTENT_REG ||
+		    extent_type == BTRFS_FILE_EXTENT_PREALLOC) {
+			disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
+			extent_end = found_key.offset +
+				btrfs_file_extent_num_bytes(leaf, fi);
+			if (extent_end <= start) {
+				path->slots[0]++;
+				goto next_slot;
+			}
+			if (disk_bytenr == 0)
+				goto out_check;
+			if (btrfs_file_extent_compression(leaf, fi) ||
+			    btrfs_file_extent_encryption(leaf, fi) ||
+			    btrfs_file_extent_other_encoding(leaf, fi))
+				goto out_check;
+			if (extent_type == BTRFS_FILE_EXTENT_REG && !force)
+				goto out_check;
+			if (btrfs_extent_readonly(root, disk_bytenr))
+				goto out_check;
+			if (btrfs_cross_ref_exist(trans, root, inode->i_ino,
+						  disk_bytenr))
+				goto out_check;
+			disk_bytenr += btrfs_file_extent_offset(leaf, fi);
+			disk_bytenr += cur_offset - found_key.offset;
+			num_bytes = min(end + 1, extent_end) - cur_offset;
+			/*
+			 * force cow if csum exists in the range.
+			 * this ensure that csum for a given extent are
+			 * either valid or do not exist.
+			 */
+			if (csum_exist_in_range(root, disk_bytenr, num_bytes))
+				goto out_check;
+			nocow = 1;
+		} else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
+			extent_end = found_key.offset +
+				btrfs_file_extent_inline_len(leaf, fi);
+			extent_end = ALIGN(extent_end, root->sectorsize);
+		} else {
+			BUG_ON(1);
+		}
+out_check:
+		if (extent_end <= start) {
+			path->slots[0]++;
+			goto next_slot;
+		}
+		if (!nocow) {
+			if (cow_start == (u64)-1)
+				cow_start = cur_offset;
+			cur_offset = extent_end;
+			if (cur_offset > end)
+				break;
+			path->slots[0]++;
+			goto next_slot;
+		}
+
+		btrfs_release_path(root, path);
+		if (cow_start != (u64)-1) {
+			ret = cow_file_range(inode, locked_page, cow_start,
+					found_key.offset - 1, page_started,
+					nr_written, 1);
+			BUG_ON(ret);
+			cow_start = (u64)-1;
+		}
+
+		if (extent_type == BTRFS_FILE_EXTENT_PREALLOC) {
+			struct extent_map *em;
+			struct extent_map_tree *em_tree;
+			em_tree = &BTRFS_I(inode)->extent_tree;
+			em = alloc_extent_map(GFP_NOFS);
+			em->start = cur_offset;
+			em->orig_start = em->start;
+			em->len = num_bytes;
+			em->block_len = num_bytes;
+			em->block_start = disk_bytenr;
+			em->bdev = root->fs_info->fs_devices->latest_bdev;
+			set_bit(EXTENT_FLAG_PINNED, &em->flags);
+			while (1) {
+				spin_lock(&em_tree->lock);
+				ret = add_extent_mapping(em_tree, em);
+				spin_unlock(&em_tree->lock);
+				if (ret != -EEXIST) {
+					free_extent_map(em);
+					break;
+				}
+				btrfs_drop_extent_cache(inode, em->start,
+						em->start + em->len - 1, 0);
+			}
+			type = BTRFS_ORDERED_PREALLOC;
+		} else {
+			type = BTRFS_ORDERED_NOCOW;
+		}
+
+		ret = btrfs_add_ordered_extent(inode, cur_offset, disk_bytenr,
+					       num_bytes, num_bytes, type);
+		BUG_ON(ret);
+
+		extent_clear_unlock_delalloc(inode, &BTRFS_I(inode)->io_tree,
+					cur_offset, cur_offset + num_bytes - 1,
+					locked_page, 1, 1, 1, 0, 0, 0);
+		cur_offset = extent_end;
+		if (cur_offset > end)
+			break;
+	}
+	btrfs_release_path(root, path);
+
+	if (cur_offset <= end && cow_start == (u64)-1)
+		cow_start = cur_offset;
+	if (cow_start != (u64)-1) {
+		ret = cow_file_range(inode, locked_page, cow_start, end,
+				     page_started, nr_written, 1);
+		BUG_ON(ret);
+	}
+
+	ret = btrfs_end_transaction(trans, root);
+	BUG_ON(ret);
+	btrfs_free_path(path);
+	return 0;
+}
+
+/*
+ * extent_io.c call back to do delayed allocation processing
+ */
+static int run_delalloc_range(struct inode *inode, struct page *locked_page,
+			      u64 start, u64 end, int *page_started,
+			      unsigned long *nr_written)
+{
+	int ret;
+
+	if (btrfs_test_flag(inode, NODATACOW))
+		ret = run_delalloc_nocow(inode, locked_page, start, end,
+					 page_started, 1, nr_written);
+	else if (btrfs_test_flag(inode, PREALLOC))
+		ret = run_delalloc_nocow(inode, locked_page, start, end,
+					 page_started, 0, nr_written);
+	else
+		ret = cow_file_range_async(inode, locked_page, start, end,
+					   page_started, nr_written);
+
+	return ret;
+}
+
+/*
+ * extent_io.c set_bit_hook, used to track delayed allocation
+ * bytes in this file, and to maintain the list of inodes that
+ * have pending delalloc work to be done.
+ */
+static int btrfs_set_bit_hook(struct inode *inode, u64 start, u64 end,
+		       unsigned long old, unsigned long bits)
+{
+	/*
+	 * set_bit and clear bit hooks normally require _irqsave/restore
+	 * but in this case, we are only testeing for the DELALLOC
+	 * bit, which is only set or cleared with irqs on
+	 */
+	if (!(old & EXTENT_DELALLOC) && (bits & EXTENT_DELALLOC)) {
+		struct btrfs_root *root = BTRFS_I(inode)->root;
+		spin_lock(&root->fs_info->delalloc_lock);
+		BTRFS_I(inode)->delalloc_bytes += end - start + 1;
+		root->fs_info->delalloc_bytes += end - start + 1;
+		if (list_empty(&BTRFS_I(inode)->delalloc_inodes)) {
+			list_add_tail(&BTRFS_I(inode)->delalloc_inodes,
+				      &root->fs_info->delalloc_inodes);
+		}
+		spin_unlock(&root->fs_info->delalloc_lock);
+	}
+	return 0;
+}
+
+/*
+ * extent_io.c clear_bit_hook, see set_bit_hook for why
+ */
+static int btrfs_clear_bit_hook(struct inode *inode, u64 start, u64 end,
+			 unsigned long old, unsigned long bits)
+{
+	/*
+	 * set_bit and clear bit hooks normally require _irqsave/restore
+	 * but in this case, we are only testeing for the DELALLOC
+	 * bit, which is only set or cleared with irqs on
+	 */
+	if ((old & EXTENT_DELALLOC) && (bits & EXTENT_DELALLOC)) {
+		struct btrfs_root *root = BTRFS_I(inode)->root;
+
+		spin_lock(&root->fs_info->delalloc_lock);
+		if (end - start + 1 > root->fs_info->delalloc_bytes) {
+			printk(KERN_INFO "btrfs warning: delalloc account "
+			       "%llu %llu\n",
+			       (unsigned long long)end - start + 1,
+			       (unsigned long long)
+			       root->fs_info->delalloc_bytes);
+			root->fs_info->delalloc_bytes = 0;
+			BTRFS_I(inode)->delalloc_bytes = 0;
+		} else {
+			root->fs_info->delalloc_bytes -= end - start + 1;
+			BTRFS_I(inode)->delalloc_bytes -= end - start + 1;
+		}
+		if (BTRFS_I(inode)->delalloc_bytes == 0 &&
+		    !list_empty(&BTRFS_I(inode)->delalloc_inodes)) {
+			list_del_init(&BTRFS_I(inode)->delalloc_inodes);
+		}
+		spin_unlock(&root->fs_info->delalloc_lock);
+	}
+	return 0;
+}
+
+/*
+ * extent_io.c merge_bio_hook, this must check the chunk tree to make sure
+ * we don't create bios that span stripes or chunks
+ */
+int btrfs_merge_bio_hook(struct page *page, unsigned long offset,
+			 size_t size, struct bio *bio,
+			 unsigned long bio_flags)
+{
+	struct btrfs_root *root = BTRFS_I(page->mapping->host)->root;
+	struct btrfs_mapping_tree *map_tree;
+	u64 logical = (u64)bio->bi_sector << 9;
+	u64 length = 0;
+	u64 map_length;
+	int ret;
+
+	if (bio_flags & EXTENT_BIO_COMPRESSED)
+		return 0;
+
+	length = bio->bi_size;
+	map_tree = &root->fs_info->mapping_tree;
+	map_length = length;
+	ret = btrfs_map_block(map_tree, READ, logical,
+			      &map_length, NULL, 0);
+
+	if (map_length < length + size)
+		return 1;
+	return 0;
+}
+
+/*
+ * in order to insert checksums into the metadata in large chunks,
+ * we wait until bio submission time.   All the pages in the bio are
+ * checksummed and sums are attached onto the ordered extent record.
+ *
+ * At IO completion time the cums attached on the ordered extent record
+ * are inserted into the btree
+ */
+static int __btrfs_submit_bio_start(struct inode *inode, int rw,
+				    struct bio *bio, int mirror_num,
+				    unsigned long bio_flags)
+{
+	struct btrfs_root *root = BTRFS_I(inode)->root;
+	int ret = 0;
+
+	ret = btrfs_csum_one_bio(root, inode, bio, 0, 0);
+	BUG_ON(ret);
+	return 0;
+}
+
+/*
+ * in order to insert checksums into the metadata in large chunks,
+ * we wait until bio submission time.   All the pages in the bio are
+ * checksummed and sums are attached onto the ordered extent record.
+ *
+ * At IO completion time the cums attached on the ordered extent record
+ * are inserted into the btree
+ */
+static int __btrfs_submit_bio_done(struct inode *inode, int rw, struct bio *bio,
+			  int mirror_num, unsigned long bio_flags)
+{
+	struct btrfs_root *root = BTRFS_I(inode)->root;
+	return btrfs_map_bio(root, rw, bio, mirror_num, 1);
+}
+
+/*
+ * extent_io.c submission hook. This does the right thing for csum calculation
+ * on write, or reading the csums from the tree before a read
+ */
+static int btrfs_submit_bio_hook(struct inode *inode, int rw, struct bio *bio,
+			  int mirror_num, unsigned long bio_flags)
+{
+	struct btrfs_root *root = BTRFS_I(inode)->root;
+	int ret = 0;
+	int skip_sum;
+
+	skip_sum = btrfs_test_flag(inode, NODATASUM);
+
+	ret = btrfs_bio_wq_end_io(root->fs_info, bio, 0);
+	BUG_ON(ret);
+
+	if (!(rw & (1 << BIO_RW))) {
+		if (bio_flags & EXTENT_BIO_COMPRESSED) {
+			return btrfs_submit_compressed_read(inode, bio,
+						    mirror_num, bio_flags);
+		} else if (!skip_sum)
+			btrfs_lookup_bio_sums(root, inode, bio, NULL);
+		goto mapit;
+	} else if (!skip_sum) {
+		/* csum items have already been cloned */
+		if (root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID)
+			goto mapit;
+		/* we're doing a write, do the async checksumming */
+		return btrfs_wq_submit_bio(BTRFS_I(inode)->root->fs_info,
+				   inode, rw, bio, mirror_num,
+				   bio_flags, __btrfs_submit_bio_start,
+				   __btrfs_submit_bio_done);
+	}
+
+mapit:
+	return btrfs_map_bio(root, rw, bio, mirror_num, 0);
+}
+
+/*
+ * given a list of ordered sums record them in the inode.  This happens
+ * at IO completion time based on sums calculated at bio submission time.
+ */
+static noinline int add_pending_csums(struct btrfs_trans_handle *trans,
+			     struct inode *inode, u64 file_offset,
+			     struct list_head *list)
+{
+	struct list_head *cur;
+	struct btrfs_ordered_sum *sum;
+
+	btrfs_set_trans_block_group(trans, inode);
+	list_for_each(cur, list) {
+		sum = list_entry(cur, struct btrfs_ordered_sum, list);
+		btrfs_csum_file_blocks(trans,
+		       BTRFS_I(inode)->root->fs_info->csum_root, sum);
+	}
+	return 0;
+}
+
+int btrfs_set_extent_delalloc(struct inode *inode, u64 start, u64 end)
+{
+	if ((end & (PAGE_CACHE_SIZE - 1)) == 0)
+		WARN_ON(1);
+	return set_extent_delalloc(&BTRFS_I(inode)->io_tree, start, end,
+				   GFP_NOFS);
+}
+
+/* see btrfs_writepage_start_hook for details on why this is required */
+struct btrfs_writepage_fixup {
+	struct page *page;
+	struct btrfs_work work;
+};
+
+static void btrfs_writepage_fixup_worker(struct btrfs_work *work)
+{
+	struct btrfs_writepage_fixup *fixup;
+	struct btrfs_ordered_extent *ordered;
+	struct page *page;
+	struct inode *inode;
+	u64 page_start;
+	u64 page_end;
+
+	fixup = container_of(work, struct btrfs_writepage_fixup, work);
+	page = fixup->page;
+again:
+	lock_page(page);
+	if (!page->mapping || !PageDirty(page) || !PageChecked(page)) {
+		ClearPageChecked(page);
+		goto out_page;
+	}
+
+	inode = page->mapping->host;
+	page_start = page_offset(page);
+	page_end = page_offset(page) + PAGE_CACHE_SIZE - 1;
+
+	lock_extent(&BTRFS_I(inode)->io_tree, page_start, page_end, GFP_NOFS);
+
+	/* already ordered? We're done */
+	if (test_range_bit(&BTRFS_I(inode)->io_tree, page_start, page_end,
+			     EXTENT_ORDERED, 0)) {
+		goto out;
+	}
+
+	ordered = btrfs_lookup_ordered_extent(inode, page_start);
+	if (ordered) {
+		unlock_extent(&BTRFS_I(inode)->io_tree, page_start,
+			      page_end, GFP_NOFS);
+		unlock_page(page);
+		btrfs_start_ordered_extent(inode, ordered, 1);
+		goto again;
+	}
+
+	btrfs_set_extent_delalloc(inode, page_start, page_end);
+	ClearPageChecked(page);
+out:
+	unlock_extent(&BTRFS_I(inode)->io_tree, page_start, page_end, GFP_NOFS);
+out_page:
+	unlock_page(page);
+	page_cache_release(page);
+}
+
+/*
+ * There are a few paths in the higher layers of the kernel that directly
+ * set the page dirty bit without asking the filesystem if it is a
+ * good idea.  This causes problems because we want to make sure COW
+ * properly happens and the data=ordered rules are followed.
+ *
+ * In our case any range that doesn't have the ORDERED bit set
+ * hasn't been properly setup for IO.  We kick off an async process
+ * to fix it up.  The async helper will wait for ordered extents, set
+ * the delalloc bit and make it safe to write the page.
+ */
+static int btrfs_writepage_start_hook(struct page *page, u64 start, u64 end)
+{
+	struct inode *inode = page->mapping->host;
+	struct btrfs_writepage_fixup *fixup;
+	struct btrfs_root *root = BTRFS_I(inode)->root;
+	int ret;
+
+	ret = test_range_bit(&BTRFS_I(inode)->io_tree, start, end,
+			     EXTENT_ORDERED, 0);
+	if (ret)
+		return 0;
+
+	if (PageChecked(page))
+		return -EAGAIN;
+
+	fixup = kzalloc(sizeof(*fixup), GFP_NOFS);
+	if (!fixup)
+		return -EAGAIN;
+
+	SetPageChecked(page);
+	page_cache_get(page);
+	fixup->work.func = btrfs_writepage_fixup_worker;
+	fixup->page = page;
+	btrfs_queue_worker(&root->fs_info->fixup_workers, &fixup->work);
+	return -EAGAIN;
+}
+
+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;
+}
+
+/* as ordered data IO finishes, this gets called so we can finish
+ * an ordered extent if the range of bytes in the file it covers are
+ * fully written.
+ */
+static int btrfs_finish_ordered_io(struct inode *inode, u64 start, u64 end)
+{
+	struct btrfs_root *root = BTRFS_I(inode)->root;
+	struct btrfs_trans_handle *trans;
+	struct btrfs_ordered_extent *ordered_extent;
+	struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
+	int compressed = 0;
+	int ret;
+
+	ret = btrfs_dec_test_ordered_pending(inode, start, end - start + 1);
+	if (!ret)
+		return 0;
+
+	trans = btrfs_join_transaction(root, 1);
+
+	ordered_extent = btrfs_lookup_ordered_extent(inode, start);
+	BUG_ON(!ordered_extent);
+	if (test_bit(BTRFS_ORDERED_NOCOW, &ordered_extent->flags))
+		goto nocow;
+
+	lock_extent(io_tree, ordered_extent->file_offset,
+		    ordered_extent->file_offset + ordered_extent->len - 1,
+		    GFP_NOFS);
+
+	if (test_bit(BTRFS_ORDERED_COMPRESSED, &ordered_extent->flags))
+		compressed = 1;
+	if (test_bit(BTRFS_ORDERED_PREALLOC, &ordered_extent->flags)) {
+		BUG_ON(compressed);
+		ret = btrfs_mark_extent_written(trans, root, inode,
+						ordered_extent->file_offset,
+						ordered_extent->file_offset +
+						ordered_extent->len);
+		BUG_ON(ret);
+	} else {
+		ret = insert_reserved_file_extent(trans, inode,
+						ordered_extent->file_offset,
+						ordered_extent->start,
+						ordered_extent->disk_len,
+						ordered_extent->len,
+						ordered_extent->len,
+						compressed, 0, 0,
+						BTRFS_FILE_EXTENT_REG);
+		BUG_ON(ret);
+	}
+	unlock_extent(io_tree, ordered_extent->file_offset,
+		    ordered_extent->file_offset + ordered_extent->len - 1,
+		    GFP_NOFS);
+nocow:
+	add_pending_csums(trans, inode, ordered_extent->file_offset,
+			  &ordered_extent->list);
+
+	mutex_lock(&BTRFS_I(inode)->extent_mutex);
+	btrfs_ordered_update_i_size(inode, ordered_extent);
+	btrfs_update_inode(trans, root, inode);
+	btrfs_remove_ordered_extent(inode, ordered_extent);
+	mutex_unlock(&BTRFS_I(inode)->extent_mutex);
+
+	/* once for us */
+	btrfs_put_ordered_extent(ordered_extent);
+	/* once for the tree */
+	btrfs_put_ordered_extent(ordered_extent);
+
+	btrfs_end_transaction(trans, root);
+	return 0;
+}
+
+static int btrfs_writepage_end_io_hook(struct page *page, u64 start, u64 end,
+				struct extent_state *state, int uptodate)
+{
+	return btrfs_finish_ordered_io(page->mapping->host, start, end);
+}
+
+/*
+ * When IO fails, either with EIO or csum verification fails, we
+ * try other mirrors that might have a good copy of the data.  This
+ * io_failure_record is used to record state as we go through all the
+ * mirrors.  If another mirror has good data, the page is set up to date
+ * and things continue.  If a good mirror can't be found, the original
+ * bio end_io callback is called to indicate things have failed.
+ */
+struct io_failure_record {
+	struct page *page;
+	u64 start;
+	u64 len;
+	u64 logical;
+	unsigned long bio_flags;
+	int last_mirror;
+};
+
+static int btrfs_io_failed_hook(struct bio *failed_bio,
+			 struct page *page, u64 start, u64 end,
+			 struct extent_state *state)
+{
+	struct io_failure_record *failrec = NULL;
+	u64 private;
+	struct extent_map *em;
+	struct inode *inode = page->mapping->host;
+	struct extent_io_tree *failure_tree = &BTRFS_I(inode)->io_failure_tree;
+	struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
+	struct bio *bio;
+	int num_copies;
+	int ret;
+	int rw;
+	u64 logical;
+
+	ret = get_state_private(failure_tree, start, &private);
+	if (ret) {
+		failrec = kmalloc(sizeof(*failrec), GFP_NOFS);
+		if (!failrec)
+			return -ENOMEM;
+		failrec->start = start;
+		failrec->len = end - start + 1;
+		failrec->last_mirror = 0;
+		failrec->bio_flags = 0;
+
+		spin_lock(&em_tree->lock);
+		em = lookup_extent_mapping(em_tree, start, failrec->len);
+		if (em->start > start || em->start + em->len < start) {
+			free_extent_map(em);
+			em = NULL;
+		}
+		spin_unlock(&em_tree->lock);
+
+		if (!em || IS_ERR(em)) {
+			kfree(failrec);
+			return -EIO;
+		}
+		logical = start - em->start;
+		logical = em->block_start + logical;
+		if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags)) {
+			logical = em->block_start;
+			failrec->bio_flags = EXTENT_BIO_COMPRESSED;
+		}
+		failrec->logical = logical;
+		free_extent_map(em);
+		set_extent_bits(failure_tree, start, end, EXTENT_LOCKED |
+				EXTENT_DIRTY, GFP_NOFS);
+		set_state_private(failure_tree, start,
+				 (u64)(unsigned long)failrec);
+	} else {
+		failrec = (struct io_failure_record *)(unsigned long)private;
+	}
+	num_copies = btrfs_num_copies(
+			      &BTRFS_I(inode)->root->fs_info->mapping_tree,
+			      failrec->logical, failrec->len);
+	failrec->last_mirror++;
+	if (!state) {
+		spin_lock(&BTRFS_I(inode)->io_tree.lock);
+		state = find_first_extent_bit_state(&BTRFS_I(inode)->io_tree,
+						    failrec->start,
+						    EXTENT_LOCKED);
+		if (state && state->start != failrec->start)
+			state = NULL;
+		spin_unlock(&BTRFS_I(inode)->io_tree.lock);
+	}
+	if (!state || failrec->last_mirror > num_copies) {
+		set_state_private(failure_tree, failrec->start, 0);
+		clear_extent_bits(failure_tree, failrec->start,
+				  failrec->start + failrec->len - 1,
+				  EXTENT_LOCKED | EXTENT_DIRTY, GFP_NOFS);
+		kfree(failrec);
+		return -EIO;
+	}
+	bio = bio_alloc(GFP_NOFS, 1);
+	bio->bi_private = state;
+	bio->bi_end_io = failed_bio->bi_end_io;
+	bio->bi_sector = failrec->logical >> 9;
+	bio->bi_bdev = failed_bio->bi_bdev;
+	bio->bi_size = 0;
+
+	bio_add_page(bio, page, failrec->len, start - page_offset(page));
+	if (failed_bio->bi_rw & (1 << BIO_RW))
+		rw = WRITE;
+	else
+		rw = READ;
+
+	BTRFS_I(inode)->io_tree.ops->submit_bio_hook(inode, rw, bio,
+						      failrec->last_mirror,
+						      failrec->bio_flags);
+	return 0;
+}
+
+/*
+ * each time an IO finishes, we do a fast check in the IO failure tree
+ * to see if we need to process or clean up an io_failure_record
+ */
+static int btrfs_clean_io_failures(struct inode *inode, u64 start)
+{
+	u64 private;
+	u64 private_failure;
+	struct io_failure_record *failure;
+	int ret;
+
+	private = 0;
+	if (count_range_bits(&BTRFS_I(inode)->io_failure_tree, &private,
+			     (u64)-1, 1, EXTENT_DIRTY)) {
+		ret = get_state_private(&BTRFS_I(inode)->io_failure_tree,
+					start, &private_failure);
+		if (ret == 0) {
+			failure = (struct io_failure_record *)(unsigned long)
+				   private_failure;
+			set_state_private(&BTRFS_I(inode)->io_failure_tree,
+					  failure->start, 0);
+			clear_extent_bits(&BTRFS_I(inode)->io_failure_tree,
+					  failure->start,
+					  failure->start + failure->len - 1,
+					  EXTENT_DIRTY | EXTENT_LOCKED,
+					  GFP_NOFS);
+			kfree(failure);
+		}
+	}
+	return 0;
+}
+
+/*
+ * when reads are done, we need to check csums to verify the data is correct
+ * if there's a match, we allow the bio to finish.  If not, we go through
+ * the io_failure_record routines to find good copies
+ */
+static int btrfs_readpage_end_io_hook(struct page *page, u64 start, u64 end,
+			       struct extent_state *state)
+{
+	size_t offset = start - ((u64)page->index << PAGE_CACHE_SHIFT);
+	struct inode *inode = page->mapping->host;
+	struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
+	char *kaddr;
+	u64 private = ~(u32)0;
+	int ret;
+	struct btrfs_root *root = BTRFS_I(inode)->root;
+	u32 csum = ~(u32)0;
+
+	if (PageChecked(page)) {
+		ClearPageChecked(page);
+		goto good;
+	}
+	if (btrfs_test_flag(inode, NODATASUM))
+		return 0;
+
+	if (root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID &&
+	    test_range_bit(io_tree, start, end, EXTENT_NODATASUM, 1)) {
+		clear_extent_bits(io_tree, start, end, EXTENT_NODATASUM,
+				  GFP_NOFS);
+		return 0;
+	}
+
+	if (state && state->start == start) {
+		private = state->private;
+		ret = 0;
+	} else {
+		ret = get_state_private(io_tree, start, &private);
+	}
+	kaddr = kmap_atomic(page, KM_USER0);
+	if (ret)
+		goto zeroit;
+
+	csum = btrfs_csum_data(root, kaddr + offset, csum,  end - start + 1);
+	btrfs_csum_final(csum, (char *)&csum);
+	if (csum != private)
+		goto zeroit;
+
+	kunmap_atomic(kaddr, KM_USER0);
+good:
+	/* if the io failure tree for this inode is non-empty,
+	 * check to see if we've recovered from a failed IO
+	 */
+	btrfs_clean_io_failures(inode, start);
+	return 0;
+
+zeroit:
+	printk(KERN_INFO "btrfs csum failed ino %lu off %llu csum %u "
+	       "private %llu\n", page->mapping->host->i_ino,
+	       (unsigned long long)start, csum,
+	       (unsigned long long)private);
+	memset(kaddr + offset, 1, end - start + 1);
+	flush_dcache_page(page);
+	kunmap_atomic(kaddr, KM_USER0);
+	if (private == 0)
+		return 0;
+	return -EIO;
+}
+
+/*
+ * 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;
+}
+
+#if 0
+/*
+ * when truncating bytes in a file, it is possible to avoid reading
+ * the leaves that contain only checksum items.  This can be the
+ * majority of the IO required to delete a large file, but it must
+ * be done carefully.
+ *
+ * The keys in the level just above the leaves are checked to make sure
+ * the lowest key in a given leaf is a csum key, and starts at an offset
+ * after the new  size.
+ *
+ * Then the key for the next leaf is checked to make sure it also has
+ * a checksum item for the same file.  If it does, we know our target leaf
+ * contains only checksum items, and it can be safely freed without reading
+ * it.
+ *
+ * This is just an optimization targeted at large files.  It may do
+ * nothing.  It will return 0 unless things went badly.
+ */
+static noinline int drop_csum_leaves(struct btrfs_trans_handle *trans,
+				     struct btrfs_root *root,
+				     struct btrfs_path *path,
+				     struct inode *inode, u64 new_size)
+{
+	struct btrfs_key key;
+	int ret;
+	int nritems;
+	struct btrfs_key found_key;
+	struct btrfs_key other_key;
+	struct btrfs_leaf_ref *ref;
+	u64 leaf_gen;
+	u64 leaf_start;
+
+	path->lowest_level = 1;
+	key.objectid = inode->i_ino;
+	key.type = BTRFS_CSUM_ITEM_KEY;
+	key.offset = new_size;
+again:
+	ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
+	if (ret < 0)
+		goto out;
+
+	if (path->nodes[1] == NULL) {
+		ret = 0;
+		goto out;
+	}
+	ret = 0;
+	btrfs_node_key_to_cpu(path->nodes[1], &found_key, path->slots[1]);
+	nritems = btrfs_header_nritems(path->nodes[1]);
+
+	if (!nritems)
+		goto out;
+
+	if (path->slots[1] >= nritems)
+		goto next_node;
+
+	/* did we find a key greater than anything we want to delete? */
+	if (found_key.objectid > inode->i_ino ||
+	   (found_key.objectid == inode->i_ino && found_key.type > key.type))
+		goto out;
+
+	/* we check the next key in the node to make sure the leave contains
+	 * only checksum items.  This comparison doesn't work if our
+	 * leaf is the last one in the node
+	 */
+	if (path->slots[1] + 1 >= nritems) {
+next_node:
+		/* search forward from the last key in the node, this
+		 * will bring us into the next node in the tree
+		 */
+		btrfs_node_key_to_cpu(path->nodes[1], &found_key, nritems - 1);
+
+		/* unlikely, but we inc below, so check to be safe */
+		if (found_key.offset == (u64)-1)
+			goto out;
+
+		/* search_forward needs a path with locks held, do the
+		 * search again for the original key.  It is possible
+		 * this will race with a balance and return a path that
+		 * we could modify, but this drop is just an optimization
+		 * and is allowed to miss some leaves.
+		 */
+		btrfs_release_path(root, path);
+		found_key.offset++;
+
+		/* setup a max key for search_forward */
+		other_key.offset = (u64)-1;
+		other_key.type = key.type;
+		other_key.objectid = key.objectid;
+
+		path->keep_locks = 1;
+		ret = btrfs_search_forward(root, &found_key, &other_key,
+					   path, 0, 0);
+		path->keep_locks = 0;
+		if (ret || found_key.objectid != key.objectid ||
+		    found_key.type != key.type) {
+			ret = 0;
+			goto out;
+		}
+
+		key.offset = found_key.offset;
+		btrfs_release_path(root, path);
+		cond_resched();
+		goto again;
+	}
+
+	/* we know there's one more slot after us in the tree,
+	 * read that key so we can verify it is also a checksum item
+	 */
+	btrfs_node_key_to_cpu(path->nodes[1], &other_key, path->slots[1] + 1);
+
+	if (found_key.objectid < inode->i_ino)
+		goto next_key;
+
+	if (found_key.type != key.type || found_key.offset < new_size)
+		goto next_key;
+
+	/*
+	 * if the key for the next leaf isn't a csum key from this objectid,
+	 * we can't be sure there aren't good items inside this leaf.
+	 * Bail out
+	 */
+	if (other_key.objectid != inode->i_ino || other_key.type != key.type)
+		goto out;
+
+	leaf_start = btrfs_node_blockptr(path->nodes[1], path->slots[1]);
+	leaf_gen = btrfs_node_ptr_generation(path->nodes[1], path->slots[1]);
+	/*
+	 * it is safe to delete this leaf, it contains only
+	 * csum items from this inode at an offset >= new_size
+	 */
+	ret = btrfs_del_leaf(trans, root, path, leaf_start);
+	BUG_ON(ret);
+
+	if (root->ref_cows && leaf_gen < trans->transid) {
+		ref = btrfs_alloc_leaf_ref(root, 0);
+		if (ref) {
+			ref->root_gen = root->root_key.offset;
+			ref->bytenr = leaf_start;
+			ref->owner = 0;
+			ref->generation = leaf_gen;
+			ref->nritems = 0;
+
+			ret = btrfs_add_leaf_ref(root, ref, 0);
+			WARN_ON(ret);
+			btrfs_free_leaf_ref(root, ref);
+		} else {
+			WARN_ON(1);
+		}
+	}
+next_key:
+	btrfs_release_path(root, path);
+
+	if (other_key.objectid == inode->i_ino &&
+	    other_key.type == key.type && other_key.offset > key.offset) {
+		key.offset = other_key.offset;
+		cond_resched();
+		goto again;
+	}
+	ret = 0;
+out:
+	/* fixup any changes we've made to the path */
+	path->lowest_level = 0;
+	path->keep_locks = 0;
+	btrfs_release_path(root, path);
+	return ret;
+}
+
+#endif
+
+/*
+ * 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;
+}
+
+/* helper for btfs_get_extent.  Given an existing extent in the tree,
+ * and an extent that you want to insert, deal with overlap and insert
+ * the new extent into the tree.
+ */
+static int merge_extent_mapping(struct extent_map_tree *em_tree,
+				struct extent_map *existing,
+				struct extent_map *em,
+				u64 map_start, u64 map_len)
+{
+	u64 start_diff;
+
+	BUG_ON(map_start < em->start || map_start >= extent_map_end(em));
+	start_diff = map_start - em->start;
+	em->start = map_start;
+	em->len = map_len;
+	if (em->block_start < EXTENT_MAP_LAST_BYTE &&
+	    !test_bit(EXTENT_FLAG_COMPRESSED, &em->flags)) {
+		em->block_start += start_diff;
+		em->block_len -= start_diff;
+	}
+	return add_extent_mapping(em_tree, em);
+}
+
+static noinline int uncompress_inline(struct btrfs_path *path,
+				      struct inode *inode, struct page *page,
+				      size_t pg_offset, u64 extent_offset,
+				      struct btrfs_file_extent_item *item)
+{
+	int ret;
+	struct extent_buffer *leaf = path->nodes[0];
+	char *tmp;
+	size_t max_size;
+	unsigned long inline_size;
+	unsigned long ptr;
+
+	WARN_ON(pg_offset != 0);
+	max_size = btrfs_file_extent_ram_bytes(leaf, item);
+	inline_size = btrfs_file_extent_inline_item_len(leaf,
+					btrfs_item_nr(leaf, path->slots[0]));
+	tmp = kmalloc(inline_size, GFP_NOFS);
+	ptr = btrfs_file_extent_inline_start(item);
+
+	read_extent_buffer(leaf, tmp, ptr, inline_size);
+
+	max_size = min_t(unsigned long, PAGE_CACHE_SIZE, max_size);
+	ret = btrfs_zlib_decompress(tmp, page, extent_offset,
+				    inline_size, max_size);
+	if (ret) {
+		char *kaddr = kmap_atomic(page, KM_USER0);
+		unsigned long copy_size = min_t(u64,
+				  PAGE_CACHE_SIZE - pg_offset,
+				  max_size - extent_offset);
+		memset(kaddr + pg_offset, 0, copy_size);
+		kunmap_atomic(kaddr, KM_USER0);
+	}
+	kfree(tmp);
+	return 0;
+}
+
+/*
+ * a bit scary, this does extent mapping from logical file offset to the disk.
+ * the ugly parts come from merging extents from the disk with the in-ram
+ * representation.  This gets more complex because of the data=ordered code,
+ * where the in-ram extents might be locked pending data=ordered completion.
+ *
+ * This also copies inline extents directly into the page.
+ */
+
+struct extent_map *btrfs_get_extent(struct inode *inode, struct page *page,
+				    size_t pg_offset, u64 start, u64 len,
+				    int create)
+{
+	int ret;
+	int err = 0;
+	u64 bytenr;
+	u64 extent_start = 0;
+	u64 extent_end = 0;
+	u64 objectid = inode->i_ino;
+	u32 found_type;
+	struct btrfs_path *path = NULL;
+	struct btrfs_root *root = BTRFS_I(inode)->root;
+	struct btrfs_file_extent_item *item;
+	struct extent_buffer *leaf;
+	struct btrfs_key found_key;
+	struct extent_map *em = NULL;
+	struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
+	struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
+	struct btrfs_trans_handle *trans = NULL;
+	int compressed;
+
+again:
+	spin_lock(&em_tree->lock);
+	em = lookup_extent_mapping(em_tree, start, len);
+	if (em)
+		em->bdev = root->fs_info->fs_devices->latest_bdev;
+	spin_unlock(&em_tree->lock);
+
+	if (em) {
+		if (em->start > start || em->start + em->len <= start)
+			free_extent_map(em);
+		else if (em->block_start == EXTENT_MAP_INLINE && page)
+			free_extent_map(em);
+		else
+			goto out;
+	}
+	em = alloc_extent_map(GFP_NOFS);
+	if (!em) {
+		err = -ENOMEM;
+		goto out;
+	}
+	em->bdev = root->fs_info->fs_devices->latest_bdev;
+	em->start = EXTENT_MAP_HOLE;
+	em->orig_start = EXTENT_MAP_HOLE;
+	em->len = (u64)-1;
+	em->block_len = (u64)-1;
+
+	if (!path) {
+		path = btrfs_alloc_path();
+		BUG_ON(!path);
+	}
+
+	ret = btrfs_lookup_file_extent(trans, root, path,
+				       objectid, start, trans != NULL);
+	if (ret < 0) {
+		err = ret;
+		goto out;
+	}
+
+	if (ret != 0) {
+		if (path->slots[0] == 0)
+			goto not_found;
+		path->slots[0]--;
+	}
+
+	leaf = path->nodes[0];
+	item = btrfs_item_ptr(leaf, path->slots[0],
+			      struct btrfs_file_extent_item);
+	/* are we inside the extent that was found? */
+	btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
+	found_type = btrfs_key_type(&found_key);
+	if (found_key.objectid != objectid ||
+	    found_type != BTRFS_EXTENT_DATA_KEY) {
+		goto not_found;
+	}
+
+	found_type = btrfs_file_extent_type(leaf, item);
+	extent_start = found_key.offset;
+	compressed = btrfs_file_extent_compression(leaf, item);
+	if (found_type == BTRFS_FILE_EXTENT_REG ||
+	    found_type == BTRFS_FILE_EXTENT_PREALLOC) {
+		extent_end = extent_start +
+		       btrfs_file_extent_num_bytes(leaf, item);
+	} else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
+		size_t size;
+		size = btrfs_file_extent_inline_len(leaf, item);
+		extent_end = (extent_start + size + root->sectorsize - 1) &
+			~((u64)root->sectorsize - 1);
+	}
+
+	if (start >= extent_end) {
+		path->slots[0]++;
+		if (path->slots[0] >= btrfs_header_nritems(leaf)) {
+			ret = btrfs_next_leaf(root, path);
+			if (ret < 0) {
+				err = ret;
+				goto out;
+			}
+			if (ret > 0)
+				goto not_found;
+			leaf = path->nodes[0];
+		}
+		btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
+		if (found_key.objectid != objectid ||
+		    found_key.type != BTRFS_EXTENT_DATA_KEY)
+			goto not_found;
+		if (start + len <= found_key.offset)
+			goto not_found;
+		em->start = start;
+		em->len = found_key.offset - start;
+		goto not_found_em;
+	}
+
+	if (found_type == BTRFS_FILE_EXTENT_REG ||
+	    found_type == BTRFS_FILE_EXTENT_PREALLOC) {
+		em->start = extent_start;
+		em->len = extent_end - extent_start;
+		em->orig_start = extent_start -
+				 btrfs_file_extent_offset(leaf, item);
+		bytenr = btrfs_file_extent_disk_bytenr(leaf, item);
+		if (bytenr == 0) {
+			em->block_start = EXTENT_MAP_HOLE;
+			goto insert;
+		}
+		if (compressed) {
+			set_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
+			em->block_start = bytenr;
+			em->block_len = btrfs_file_extent_disk_num_bytes(leaf,
+									 item);
+		} else {
+			bytenr += btrfs_file_extent_offset(leaf, item);
+			em->block_start = bytenr;
+			em->block_len = em->len;
+			if (found_type == BTRFS_FILE_EXTENT_PREALLOC)
+				set_bit(EXTENT_FLAG_PREALLOC, &em->flags);
+		}
+		goto insert;
+	} else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
+		unsigned long ptr;
+		char *map;
+		size_t size;
+		size_t extent_offset;
+		size_t copy_size;
+
+		em->block_start = EXTENT_MAP_INLINE;
+		if (!page || create) {
+			em->start = extent_start;
+			em->len = extent_end - extent_start;
+			goto out;
+		}
+
+		size = btrfs_file_extent_inline_len(leaf, item);
+		extent_offset = page_offset(page) + pg_offset - extent_start;
+		copy_size = min_t(u64, PAGE_CACHE_SIZE - pg_offset,
+				size - extent_offset);
+		em->start = extent_start + extent_offset;
+		em->len = (copy_size + root->sectorsize - 1) &
+			~((u64)root->sectorsize - 1);
+		em->orig_start = EXTENT_MAP_INLINE;
+		if (compressed)
+			set_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
+		ptr = btrfs_file_extent_inline_start(item) + extent_offset;
+		if (create == 0 && !PageUptodate(page)) {
+			if (btrfs_file_extent_compression(leaf, item) ==
+			    BTRFS_COMPRESS_ZLIB) {
+				ret = uncompress_inline(path, inode, page,
+							pg_offset,
+							extent_offset, item);
+				BUG_ON(ret);
+			} else {
+				map = kmap(page);
+				read_extent_buffer(leaf, map + pg_offset, ptr,
+						   copy_size);
+				kunmap(page);
+			}
+			flush_dcache_page(page);
+		} else if (create && PageUptodate(page)) {
+			if (!trans) {
+				kunmap(page);
+				free_extent_map(em);
+				em = NULL;
+				btrfs_release_path(root, path);
+				trans = btrfs_join_transaction(root, 1);
+				goto again;
+			}
+			map = kmap(page);
+			write_extent_buffer(leaf, map + pg_offset, ptr,
+					    copy_size);
+			kunmap(page);
+			btrfs_mark_buffer_dirty(leaf);
+		}
+		set_extent_uptodate(io_tree, em->start,
+				    extent_map_end(em) - 1, GFP_NOFS);
+		goto insert;
+	} else {
+		printk(KERN_ERR "btrfs unknown found_type %d\n", found_type);
+		WARN_ON(1);
+	}
+not_found:
+	em->start = start;
+	em->len = len;
+not_found_em:
+	em->block_start = EXTENT_MAP_HOLE;
+	set_bit(EXTENT_FLAG_VACANCY, &em->flags);
+insert:
+	btrfs_release_path(root, path);
+	if (em->start > start || extent_map_end(em) <= start) {
+		printk(KERN_ERR "Btrfs: bad extent! em: [%llu %llu] passed "
+		       "[%llu %llu]\n", (unsigned long long)em->start,
+		       (unsigned long long)em->len,
+		       (unsigned long long)start,
+		       (unsigned long long)len);
+		err = -EIO;
+		goto out;
+	}
+
+	err = 0;
+	spin_lock(&em_tree->lock);
+	ret = add_extent_mapping(em_tree, em);
+	/* it is possible that someone inserted the extent into the tree
+	 * while we had the lock dropped.  It is also possible that
+	 * an overlapping map exists in the tree
+	 */
+	if (ret == -EEXIST) {
+		struct extent_map *existing;
+
+		ret = 0;
+
+		existing = lookup_extent_mapping(em_tree, start, len);
+		if (existing && (existing->start > start ||
+		    existing->start + existing->len <= start)) {
+			free_extent_map(existing);
+			existing = NULL;
+		}
+		if (!existing) {
+			existing = lookup_extent_mapping(em_tree, em->start,
+							 em->len);
+			if (existing) {
+				err = merge_extent_mapping(em_tree, existing,
+							   em, start,
+							   root->sectorsize);
+				free_extent_map(existing);
+				if (err) {
+					free_extent_map(em);
+					em = NULL;
+				}
+			} else {
+				err = -EIO;
+				free_extent_map(em);
+				em = NULL;
+			}
+		} else {
+			free_extent_map(em);
+			em = existing;
+			err = 0;
+		}
+	}
+	spin_unlock(&em_tree->lock);
+out:
+	if (path)
+		btrfs_free_path(path);
+	if (trans) {
+		ret = btrfs_end_transaction(trans, root);
+		if (!err)
+			err = ret;
+	}
+	if (err) {
+		free_extent_map(em);
+		WARN_ON(1);
+		return ERR_PTR(err);
+	}
+	return em;
+}
+
+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 extent_io_ops btrfs_extent_io_ops = {
+	.fill_delalloc = run_delalloc_range,
+	.submit_bio_hook = btrfs_submit_bio_hook,
+	.merge_bio_hook = btrfs_merge_bio_hook,
+	.readpage_end_io_hook = btrfs_readpage_end_io_hook,
+	.writepage_end_io_hook = btrfs_writepage_end_io_hook,
+	.writepage_start_hook = btrfs_writepage_start_hook,
+	.readpage_io_failed_hook = btrfs_io_failed_hook,
+	.set_bit_hook = btrfs_set_bit_hook,
+	.clear_bit_hook = btrfs_clear_bit_hook,
+};
+
+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,
+};