init android origin source code

1 files changed, 1908 insertions, 0 deletions

diff --git a/ANDROID_3.4.5/fs/btrfs/file.c b/ANDROID_3.4.5/fs/btrfs/file.c
new file mode 100644
index 00000000..53bf2d76
--- /dev/null
+++ b/ANDROID_3.4.5/fs/btrfs/file.c
@@ -0,0 +1,1908 @@
+/*
+ * 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/fs.h>
+#include <linux/pagemap.h>
+#include <linux/highmem.h>
+#include <linux/time.h>
+#include <linux/init.h>
+#include <linux/string.h>
+#include <linux/backing-dev.h>
+#include <linux/mpage.h>
+#include <linux/falloc.h>
+#include <linux/swap.h>
+#include <linux/writeback.h>
+#include <linux/statfs.h>
+#include <linux/compat.h>
+#include <linux/slab.h>
+#include "ctree.h"
+#include "disk-io.h"
+#include "transaction.h"
+#include "btrfs_inode.h"
+#include "ioctl.h"
+#include "print-tree.h"
+#include "tree-log.h"
+#include "locking.h"
+#include "compat.h"
+
+/*
+ * when auto defrag is enabled we
+ * queue up these defrag structs to remember which
+ * inodes need defragging passes
+ */
+struct inode_defrag {
+	struct rb_node rb_node;
+	/* objectid */
+	u64 ino;
+	/*
+	 * transid where the defrag was added, we search for
+	 * extents newer than this
+	 */
+	u64 transid;
+
+	/* root objectid */
+	u64 root;
+
+	/* last offset we were able to defrag */
+	u64 last_offset;
+
+	/* if we've wrapped around back to zero once already */
+	int cycled;
+};
+
+/* pop a record for an inode into the defrag tree.  The lock
+ * must be held already
+ *
+ * If you're inserting a record for an older transid than an
+ * existing record, the transid already in the tree is lowered
+ *
+ * If an existing record is found the defrag item you
+ * pass in is freed
+ */
+static void __btrfs_add_inode_defrag(struct inode *inode,
+				    struct inode_defrag *defrag)
+{
+	struct btrfs_root *root = BTRFS_I(inode)->root;
+	struct inode_defrag *entry;
+	struct rb_node **p;
+	struct rb_node *parent = NULL;
+
+	p = &root->fs_info->defrag_inodes.rb_node;
+	while (*p) {
+		parent = *p;
+		entry = rb_entry(parent, struct inode_defrag, rb_node);
+
+		if (defrag->ino < entry->ino)
+			p = &parent->rb_left;
+		else if (defrag->ino > entry->ino)
+			p = &parent->rb_right;
+		else {
+			/* if we're reinserting an entry for
+			 * an old defrag run, make sure to
+			 * lower the transid of our existing record
+			 */
+			if (defrag->transid < entry->transid)
+				entry->transid = defrag->transid;
+			if (defrag->last_offset > entry->last_offset)
+				entry->last_offset = defrag->last_offset;
+			goto exists;
+		}
+	}
+	BTRFS_I(inode)->in_defrag = 1;
+	rb_link_node(&defrag->rb_node, parent, p);
+	rb_insert_color(&defrag->rb_node, &root->fs_info->defrag_inodes);
+	return;
+
+exists:
+	kfree(defrag);
+	return;
+
+}
+
+/*
+ * insert a defrag record for this inode if auto defrag is
+ * enabled
+ */
+int btrfs_add_inode_defrag(struct btrfs_trans_handle *trans,
+			   struct inode *inode)
+{
+	struct btrfs_root *root = BTRFS_I(inode)->root;
+	struct inode_defrag *defrag;
+	u64 transid;
+
+	if (!btrfs_test_opt(root, AUTO_DEFRAG))
+		return 0;
+
+	if (btrfs_fs_closing(root->fs_info))
+		return 0;
+
+	if (BTRFS_I(inode)->in_defrag)
+		return 0;
+
+	if (trans)
+		transid = trans->transid;
+	else
+		transid = BTRFS_I(inode)->root->last_trans;
+
+	defrag = kzalloc(sizeof(*defrag), GFP_NOFS);
+	if (!defrag)
+		return -ENOMEM;
+
+	defrag->ino = btrfs_ino(inode);
+	defrag->transid = transid;
+	defrag->root = root->root_key.objectid;
+
+	spin_lock(&root->fs_info->defrag_inodes_lock);
+	if (!BTRFS_I(inode)->in_defrag)
+		__btrfs_add_inode_defrag(inode, defrag);
+	else
+		kfree(defrag);
+	spin_unlock(&root->fs_info->defrag_inodes_lock);
+	return 0;
+}
+
+/*
+ * must be called with the defrag_inodes lock held
+ */
+struct inode_defrag *btrfs_find_defrag_inode(struct btrfs_fs_info *info, u64 ino,
+					     struct rb_node **next)
+{
+	struct inode_defrag *entry = NULL;
+	struct rb_node *p;
+	struct rb_node *parent = NULL;
+
+	p = info->defrag_inodes.rb_node;
+	while (p) {
+		parent = p;
+		entry = rb_entry(parent, struct inode_defrag, rb_node);
+
+		if (ino < entry->ino)
+			p = parent->rb_left;
+		else if (ino > entry->ino)
+			p = parent->rb_right;
+		else
+			return entry;
+	}
+
+	if (next) {
+		while (parent && ino > entry->ino) {
+			parent = rb_next(parent);
+			entry = rb_entry(parent, struct inode_defrag, rb_node);
+		}
+		*next = parent;
+	}
+	return NULL;
+}
+
+/*
+ * run through the list of inodes in the FS that need
+ * defragging
+ */
+int btrfs_run_defrag_inodes(struct btrfs_fs_info *fs_info)
+{
+	struct inode_defrag *defrag;
+	struct btrfs_root *inode_root;
+	struct inode *inode;
+	struct rb_node *n;
+	struct btrfs_key key;
+	struct btrfs_ioctl_defrag_range_args range;
+	u64 first_ino = 0;
+	int num_defrag;
+	int defrag_batch = 1024;
+
+	memset(&range, 0, sizeof(range));
+	range.len = (u64)-1;
+
+	atomic_inc(&fs_info->defrag_running);
+	spin_lock(&fs_info->defrag_inodes_lock);
+	while(1) {
+		n = NULL;
+
+		/* find an inode to defrag */
+		defrag = btrfs_find_defrag_inode(fs_info, first_ino, &n);
+		if (!defrag) {
+			if (n)
+				defrag = rb_entry(n, struct inode_defrag, rb_node);
+			else if (first_ino) {
+				first_ino = 0;
+				continue;
+			} else {
+				break;
+			}
+		}
+
+		/* remove it from the rbtree */
+		first_ino = defrag->ino + 1;
+		rb_erase(&defrag->rb_node, &fs_info->defrag_inodes);
+
+		if (btrfs_fs_closing(fs_info))
+			goto next_free;
+
+		spin_unlock(&fs_info->defrag_inodes_lock);
+
+		/* get the inode */
+		key.objectid = defrag->root;
+		btrfs_set_key_type(&key, BTRFS_ROOT_ITEM_KEY);
+		key.offset = (u64)-1;
+		inode_root = btrfs_read_fs_root_no_name(fs_info, &key);
+		if (IS_ERR(inode_root))
+			goto next;
+
+		key.objectid = defrag->ino;
+		btrfs_set_key_type(&key, BTRFS_INODE_ITEM_KEY);
+		key.offset = 0;
+
+		inode = btrfs_iget(fs_info->sb, &key, inode_root, NULL);
+		if (IS_ERR(inode))
+			goto next;
+
+		/* do a chunk of defrag */
+		BTRFS_I(inode)->in_defrag = 0;
+		range.start = defrag->last_offset;
+		num_defrag = btrfs_defrag_file(inode, NULL, &range, defrag->transid,
+					       defrag_batch);
+		/*
+		 * if we filled the whole defrag batch, there
+		 * must be more work to do.  Queue this defrag
+		 * again
+		 */
+		if (num_defrag == defrag_batch) {
+			defrag->last_offset = range.start;
+			__btrfs_add_inode_defrag(inode, defrag);
+			/*
+			 * we don't want to kfree defrag, we added it back to
+			 * the rbtree
+			 */
+			defrag = NULL;
+		} else if (defrag->last_offset && !defrag->cycled) {
+			/*
+			 * we didn't fill our defrag batch, but
+			 * we didn't start at zero.  Make sure we loop
+			 * around to the start of the file.
+			 */
+			defrag->last_offset = 0;
+			defrag->cycled = 1;
+			__btrfs_add_inode_defrag(inode, defrag);
+			defrag = NULL;
+		}
+
+		iput(inode);
+next:
+		spin_lock(&fs_info->defrag_inodes_lock);
+next_free:
+		kfree(defrag);
+	}
+	spin_unlock(&fs_info->defrag_inodes_lock);
+
+	atomic_dec(&fs_info->defrag_running);
+
+	/*
+	 * during unmount, we use the transaction_wait queue to
+	 * wait for the defragger to stop
+	 */
+	wake_up(&fs_info->transaction_wait);
+	return 0;
+}
+
+/* simple helper to fault in pages and copy.  This should go away
+ * and be replaced with calls into generic code.
+ */
+static noinline int btrfs_copy_from_user(loff_t pos, int num_pages,
+					 size_t write_bytes,
+					 struct page **prepared_pages,
+					 struct iov_iter *i)
+{
+	size_t copied = 0;
+	size_t total_copied = 0;
+	int pg = 0;
+	int offset = pos & (PAGE_CACHE_SIZE - 1);
+
+	while (write_bytes > 0) {
+		size_t count = min_t(size_t,
+				     PAGE_CACHE_SIZE - offset, write_bytes);
+		struct page *page = prepared_pages[pg];
+		/*
+		 * Copy data from userspace to the current page
+		 *
+		 * Disable pagefault to avoid recursive lock since
+		 * the pages are already locked
+		 */
+		pagefault_disable();
+		copied = iov_iter_copy_from_user_atomic(page, i, offset, count);
+		pagefault_enable();
+
+		/* Flush processor's dcache for this page */
+		flush_dcache_page(page);
+
+		/*
+		 * if we get a partial write, we can end up with
+		 * partially up to date pages.  These add
+		 * a lot of complexity, so make sure they don't
+		 * happen by forcing this copy to be retried.
+		 *
+		 * The rest of the btrfs_file_write code will fall
+		 * back to page at a time copies after we return 0.
+		 */
+		if (!PageUptodate(page) && copied < count)
+			copied = 0;
+
+		iov_iter_advance(i, copied);
+		write_bytes -= copied;
+		total_copied += copied;
+
+		/* Return to btrfs_file_aio_write to fault page */
+		if (unlikely(copied == 0))
+			break;
+
+		if (unlikely(copied < PAGE_CACHE_SIZE - offset)) {
+			offset += copied;
+		} else {
+			pg++;
+			offset = 0;
+		}
+	}
+	return total_copied;
+}
+
+/*
+ * unlocks pages after btrfs_file_write is done with them
+ */
+void btrfs_drop_pages(struct page **pages, size_t num_pages)
+{
+	size_t i;
+	for (i = 0; i < num_pages; i++) {
+		/* page checked is some magic around finding pages that
+		 * have been modified without going through btrfs_set_page_dirty
+		 * clear it here
+		 */
+		ClearPageChecked(pages[i]);
+		unlock_page(pages[i]);
+		mark_page_accessed(pages[i]);
+		page_cache_release(pages[i]);
+	}
+}
+
+/*
+ * after copy_from_user, pages need to be dirtied and we need to make
+ * sure holes are created between the current EOF and the start of
+ * any next extents (if required).
+ *
+ * this also makes the decision about creating an inline extent vs
+ * doing real data extents, marking pages dirty and delalloc as required.
+ */
+int btrfs_dirty_pages(struct btrfs_root *root, struct inode *inode,
+		      struct page **pages, size_t num_pages,
+		      loff_t pos, size_t write_bytes,
+		      struct extent_state **cached)
+{
+	int err = 0;
+	int i;
+	u64 num_bytes;
+	u64 start_pos;
+	u64 end_of_last_block;
+	u64 end_pos = pos + write_bytes;
+	loff_t isize = i_size_read(inode);
+
+	start_pos = pos & ~((u64)root->sectorsize - 1);
+	num_bytes = (write_bytes + pos - start_pos +
+		    root->sectorsize - 1) & ~((u64)root->sectorsize - 1);
+
+	end_of_last_block = start_pos + num_bytes - 1;
+	err = btrfs_set_extent_delalloc(inode, start_pos, end_of_last_block,
+					cached);
+	if (err)
+		return err;
+
+	for (i = 0; i < num_pages; i++) {
+		struct page *p = pages[i];
+		SetPageUptodate(p);
+		ClearPageChecked(p);
+		set_page_dirty(p);
+	}
+
+	/*
+	 * we've only changed i_size in ram, and we haven't updated
+	 * the disk i_size.  There is no need to log the inode
+	 * at this time.
+	 */
+	if (end_pos > isize)
+		i_size_write(inode, end_pos);
+	return 0;
+}
+
+/*
+ * this drops all the extents in the cache that intersect the range
+ * [start, end].  Existing extents are split as required.
+ */
+int btrfs_drop_extent_cache(struct inode *inode, u64 start, u64 end,
+			    int skip_pinned)
+{
+	struct extent_map *em;
+	struct extent_map *split = NULL;
+	struct extent_map *split2 = NULL;
+	struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
+	u64 len = end - start + 1;
+	int ret;
+	int testend = 1;
+	unsigned long flags;
+	int compressed = 0;
+
+	WARN_ON(end < start);
+	if (end == (u64)-1) {
+		len = (u64)-1;
+		testend = 0;
+	}
+	while (1) {
+		if (!split)
+			split = alloc_extent_map();
+		if (!split2)
+			split2 = alloc_extent_map();
+		BUG_ON(!split || !split2); /* -ENOMEM */
+
+		write_lock(&em_tree->lock);
+		em = lookup_extent_mapping(em_tree, start, len);
+		if (!em) {
+			write_unlock(&em_tree->lock);
+			break;
+		}
+		flags = em->flags;
+		if (skip_pinned && test_bit(EXTENT_FLAG_PINNED, &em->flags)) {
+			if (testend && em->start + em->len >= start + len) {
+				free_extent_map(em);
+				write_unlock(&em_tree->lock);
+				break;
+			}
+			start = em->start + em->len;
+			if (testend)
+				len = start + len - (em->start + em->len);
+			free_extent_map(em);
+			write_unlock(&em_tree->lock);
+			continue;
+		}
+		compressed = test_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
+		clear_bit(EXTENT_FLAG_PINNED, &em->flags);
+		remove_extent_mapping(em_tree, em);
+
+		if (em->block_start < EXTENT_MAP_LAST_BYTE &&
+		    em->start < start) {
+			split->start = em->start;
+			split->len = start - em->start;
+			split->orig_start = em->orig_start;
+			split->block_start = em->block_start;
+
+			if (compressed)
+				split->block_len = em->block_len;
+			else
+				split->block_len = split->len;
+
+			split->bdev = em->bdev;
+			split->flags = flags;
+			split->compress_type = em->compress_type;
+			ret = add_extent_mapping(em_tree, split);
+			BUG_ON(ret); /* Logic error */
+			free_extent_map(split);
+			split = split2;
+			split2 = NULL;
+		}
+		if (em->block_start < EXTENT_MAP_LAST_BYTE &&
+		    testend && em->start + em->len > start + len) {
+			u64 diff = start + len - em->start;
+
+			split->start = start + len;
+			split->len = em->start + em->len - (start + len);
+			split->bdev = em->bdev;
+			split->flags = flags;
+			split->compress_type = em->compress_type;
+
+			if (compressed) {
+				split->block_len = em->block_len;
+				split->block_start = em->block_start;
+				split->orig_start = em->orig_start;
+			} else {
+				split->block_len = split->len;
+				split->block_start = em->block_start + diff;
+				split->orig_start = split->start;
+			}
+
+			ret = add_extent_mapping(em_tree, split);
+			BUG_ON(ret); /* Logic error */
+			free_extent_map(split);
+			split = NULL;
+		}
+		write_unlock(&em_tree->lock);
+
+		/* once for us */
+		free_extent_map(em);
+		/* once for the tree*/
+		free_extent_map(em);
+	}
+	if (split)
+		free_extent_map(split);
+	if (split2)
+		free_extent_map(split2);
+	return 0;
+}
+
+/*
+ * this is very complex, but the basic idea is to drop all extents
+ * in the range start - end.  hint_block is filled in with a block number
+ * that would be a good hint to the block allocator for this file.
+ *
+ * If an extent intersects the range but is not entirely inside the range
+ * it is either truncated or split.  Anything entirely inside the range
+ * is deleted from the tree.
+ */
+int btrfs_drop_extents(struct btrfs_trans_handle *trans, struct inode *inode,
+		       u64 start, u64 end, u64 *hint_byte, int drop_cache)
+{
+	struct btrfs_root *root = BTRFS_I(inode)->root;
+	struct extent_buffer *leaf;
+	struct btrfs_file_extent_item *fi;
+	struct btrfs_path *path;
+	struct btrfs_key key;
+	struct btrfs_key new_key;
+	u64 ino = btrfs_ino(inode);
+	u64 search_start = start;
+	u64 disk_bytenr = 0;
+	u64 num_bytes = 0;
+	u64 extent_offset = 0;
+	u64 extent_end = 0;
+	int del_nr = 0;
+	int del_slot = 0;
+	int extent_type;
+	int recow;
+	int ret;
+	int modify_tree = -1;
+
+	if (drop_cache)
+		btrfs_drop_extent_cache(inode, start, end - 1, 0);
+
+	path = btrfs_alloc_path();
+	if (!path)
+		return -ENOMEM;
+
+	if (start >= BTRFS_I(inode)->disk_i_size)
+		modify_tree = 0;
+
+	while (1) {
+		recow = 0;
+		ret = btrfs_lookup_file_extent(trans, root, path, ino,
+					       search_start, modify_tree);
+		if (ret < 0)
+			break;
+		if (ret > 0 && path->slots[0] > 0 && search_start == start) {
+			leaf = path->nodes[0];
+			btrfs_item_key_to_cpu(leaf, &key, path->slots[0] - 1);
+			if (key.objectid == ino &&
+			    key.type == BTRFS_EXTENT_DATA_KEY)
+				path->slots[0]--;
+		}
+		ret = 0;
+next_slot:
+		leaf = path->nodes[0];
+		if (path->slots[0] >= btrfs_header_nritems(leaf)) {
+			BUG_ON(del_nr > 0);
+			ret = btrfs_next_leaf(root, path);
+			if (ret < 0)
+				break;
+			if (ret > 0) {
+				ret = 0;
+				break;
+			}
+			leaf = path->nodes[0];
+			recow = 1;
+		}
+
+		btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
+		if (key.objectid > ino ||
+		    key.type > BTRFS_EXTENT_DATA_KEY || key.offset >= end)
+			break;
+
+		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);
+			num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
+			extent_offset = btrfs_file_extent_offset(leaf, fi);
+			extent_end = key.offset +
+				btrfs_file_extent_num_bytes(leaf, fi);
+		} else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
+			extent_end = key.offset +
+				btrfs_file_extent_inline_len(leaf, fi);
+		} else {
+			WARN_ON(1);
+			extent_end = search_start;
+		}
+
+		if (extent_end <= search_start) {
+			path->slots[0]++;
+			goto next_slot;
+		}
+
+		search_start = max(key.offset, start);
+		if (recow || !modify_tree) {
+			modify_tree = -1;
+			btrfs_release_path(path);
+			continue;
+		}
+
+		/*
+		 *     | - range to drop - |
+		 *  | -------- extent -------- |
+		 */
+		if (start > key.offset && end < extent_end) {
+			BUG_ON(del_nr > 0);
+			BUG_ON(extent_type == BTRFS_FILE_EXTENT_INLINE);
+
+			memcpy(&new_key, &key, sizeof(new_key));
+			new_key.offset = start;
+			ret = btrfs_duplicate_item(trans, root, path,
+						   &new_key);
+			if (ret == -EAGAIN) {
+				btrfs_release_path(path);
+				continue;
+			}
+			if (ret < 0)
+				break;
+
+			leaf = path->nodes[0];
+			fi = btrfs_item_ptr(leaf, path->slots[0] - 1,
+					    struct btrfs_file_extent_item);
+			btrfs_set_file_extent_num_bytes(leaf, fi,
+							start - key.offset);
+
+			fi = btrfs_item_ptr(leaf, path->slots[0],
+					    struct btrfs_file_extent_item);
+
+			extent_offset += start - key.offset;
+			btrfs_set_file_extent_offset(leaf, fi, extent_offset);
+			btrfs_set_file_extent_num_bytes(leaf, fi,
+							extent_end - start);
+			btrfs_mark_buffer_dirty(leaf);
+
+			if (disk_bytenr > 0) {
+				ret = btrfs_inc_extent_ref(trans, root,
+						disk_bytenr, num_bytes, 0,
+						root->root_key.objectid,
+						new_key.objectid,
+						start - extent_offset, 0);
+				BUG_ON(ret); /* -ENOMEM */
+				*hint_byte = disk_bytenr;
+			}
+			key.offset = start;
+		}
+		/*
+		 *  | ---- range to drop ----- |
+		 *      | -------- extent -------- |
+		 */
+		if (start <= key.offset && end < extent_end) {
+			BUG_ON(extent_type == BTRFS_FILE_EXTENT_INLINE);
+
+			memcpy(&new_key, &key, sizeof(new_key));
+			new_key.offset = end;
+			btrfs_set_item_key_safe(trans, root, path, &new_key);
+
+			extent_offset += end - key.offset;
+			btrfs_set_file_extent_offset(leaf, fi, extent_offset);
+			btrfs_set_file_extent_num_bytes(leaf, fi,
+							extent_end - end);
+			btrfs_mark_buffer_dirty(leaf);
+			if (disk_bytenr > 0) {
+				inode_sub_bytes(inode, end - key.offset);
+				*hint_byte = disk_bytenr;
+			}
+			break;
+		}
+
+		search_start = extent_end;
+		/*
+		 *       | ---- range to drop ----- |
+		 *  | -------- extent -------- |
+		 */
+		if (start > key.offset && end >= extent_end) {
+			BUG_ON(del_nr > 0);
+			BUG_ON(extent_type == BTRFS_FILE_EXTENT_INLINE);
+
+			btrfs_set_file_extent_num_bytes(leaf, fi,
+							start - key.offset);
+			btrfs_mark_buffer_dirty(leaf);
+			if (disk_bytenr > 0) {
+				inode_sub_bytes(inode, extent_end - start);
+				*hint_byte = disk_bytenr;
+			}
+			if (end == extent_end)
+				break;
+
+			path->slots[0]++;
+			goto next_slot;
+		}
+
+		/*
+		 *  | ---- range to drop ----- |
+		 *    | ------ extent ------ |
+		 */
+		if (start <= key.offset && end >= extent_end) {
+			if (del_nr == 0) {
+				del_slot = path->slots[0];
+				del_nr = 1;
+			} else {
+				BUG_ON(del_slot + del_nr != path->slots[0]);
+				del_nr++;
+			}
+
+			if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
+				inode_sub_bytes(inode,
+						extent_end - key.offset);
+				extent_end = ALIGN(extent_end,
+						   root->sectorsize);
+			} else if (disk_bytenr > 0) {
+				ret = btrfs_free_extent(trans, root,
+						disk_bytenr, num_bytes, 0,
+						root->root_key.objectid,
+						key.objectid, key.offset -
+						extent_offset, 0);
+				BUG_ON(ret); /* -ENOMEM */
+				inode_sub_bytes(inode,
+						extent_end - key.offset);
+				*hint_byte = disk_bytenr;
+			}
+
+			if (end == extent_end)
+				break;
+
+			if (path->slots[0] + 1 < btrfs_header_nritems(leaf)) {
+				path->slots[0]++;
+				goto next_slot;
+			}
+
+			ret = btrfs_del_items(trans, root, path, del_slot,
+					      del_nr);
+			if (ret) {
+				btrfs_abort_transaction(trans, root, ret);
+				goto out;
+			}
+
+			del_nr = 0;
+			del_slot = 0;
+
+			btrfs_release_path(path);
+			continue;
+		}
+
+		BUG_ON(1);
+	}
+
+	if (!ret && del_nr > 0) {
+		ret = btrfs_del_items(trans, root, path, del_slot, del_nr);
+		if (ret)
+			btrfs_abort_transaction(trans, root, ret);
+	}
+
+out:
+	btrfs_free_path(path);
+	return ret;
+}
+
+static int extent_mergeable(struct extent_buffer *leaf, int slot,
+			    u64 objectid, u64 bytenr, u64 orig_offset,
+			    u64 *start, u64 *end)
+{
+	struct btrfs_file_extent_item *fi;
+	struct btrfs_key key;
+	u64 extent_end;
+
+	if (slot < 0 || slot >= btrfs_header_nritems(leaf))
+		return 0;
+
+	btrfs_item_key_to_cpu(leaf, &key, slot);
+	if (key.objectid != objectid || key.type != BTRFS_EXTENT_DATA_KEY)
+		return 0;
+
+	fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
+	if (btrfs_file_extent_type(leaf, fi) != BTRFS_FILE_EXTENT_REG ||
+	    btrfs_file_extent_disk_bytenr(leaf, fi) != bytenr ||
+	    btrfs_file_extent_offset(leaf, fi) != key.offset - orig_offset ||
+	    btrfs_file_extent_compression(leaf, fi) ||
+	    btrfs_file_extent_encryption(leaf, fi) ||
+	    btrfs_file_extent_other_encoding(leaf, fi))
+		return 0;
+
+	extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
+	if ((*start && *start != key.offset) || (*end && *end != extent_end))
+		return 0;
+
+	*start = key.offset;
+	*end = extent_end;
+	return 1;
+}
+
+/*
+ * Mark extent in the range start - end as written.
+ *
+ * This changes extent type from 'pre-allocated' to 'regular'. If only
+ * part of extent is marked as written, the extent will be split into
+ * two or three.
+ */
+int btrfs_mark_extent_written(struct btrfs_trans_handle *trans,
+			      struct inode *inode, u64 start, u64 end)
+{
+	struct btrfs_root *root = BTRFS_I(inode)->root;
+	struct extent_buffer *leaf;
+	struct btrfs_path *path;
+	struct btrfs_file_extent_item *fi;
+	struct btrfs_key key;
+	struct btrfs_key new_key;
+	u64 bytenr;
+	u64 num_bytes;
+	u64 extent_end;
+	u64 orig_offset;
+	u64 other_start;
+	u64 other_end;
+	u64 split;
+	int del_nr = 0;
+	int del_slot = 0;
+	int recow;
+	int ret;
+	u64 ino = btrfs_ino(inode);
+
+	btrfs_drop_extent_cache(inode, start, end - 1, 0);
+
+	path = btrfs_alloc_path();
+	if (!path)
+		return -ENOMEM;
+again:
+	recow = 0;
+	split = start;
+	key.objectid = ino;
+	key.type = BTRFS_EXTENT_DATA_KEY;
+	key.offset = split;
+
+	ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
+	if (ret < 0)
+		goto out;
+	if (ret > 0 && path->slots[0] > 0)
+		path->slots[0]--;
+
+	leaf = path->nodes[0];
+	btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
+	BUG_ON(key.objectid != ino || key.type != BTRFS_EXTENT_DATA_KEY);
+	fi = btrfs_item_ptr(leaf, path->slots[0],
+			    struct btrfs_file_extent_item);
+	BUG_ON(btrfs_file_extent_type(leaf, fi) !=
+	       BTRFS_FILE_EXTENT_PREALLOC);
+	extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
+	BUG_ON(key.offset > start || extent_end < end);
+
+	bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
+	num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
+	orig_offset = key.offset - btrfs_file_extent_offset(leaf, fi);
+	memcpy(&new_key, &key, sizeof(new_key));
+
+	if (start == key.offset && end < extent_end) {
+		other_start = 0;
+		other_end = start;
+		if (extent_mergeable(leaf, path->slots[0] - 1,
+				     ino, bytenr, orig_offset,
+				     &other_start, &other_end)) {
+			new_key.offset = end;
+			btrfs_set_item_key_safe(trans, root, path, &new_key);
+			fi = btrfs_item_ptr(leaf, path->slots[0],
+					    struct btrfs_file_extent_item);
+			btrfs_set_file_extent_num_bytes(leaf, fi,
+							extent_end - end);
+			btrfs_set_file_extent_offset(leaf, fi,
+						     end - orig_offset);
+			fi = btrfs_item_ptr(leaf, path->slots[0] - 1,
+					    struct btrfs_file_extent_item);
+			btrfs_set_file_extent_num_bytes(leaf, fi,
+							end - other_start);
+			btrfs_mark_buffer_dirty(leaf);
+			goto out;
+		}
+	}
+
+	if (start > key.offset && end == extent_end) {
+		other_start = end;
+		other_end = 0;
+		if (extent_mergeable(leaf, path->slots[0] + 1,
+				     ino, bytenr, orig_offset,
+				     &other_start, &other_end)) {
+			fi = btrfs_item_ptr(leaf, path->slots[0],
+					    struct btrfs_file_extent_item);
+			btrfs_set_file_extent_num_bytes(leaf, fi,
+							start - key.offset);
+			path->slots[0]++;
+			new_key.offset = start;
+			btrfs_set_item_key_safe(trans, root, path, &new_key);
+
+			fi = btrfs_item_ptr(leaf, path->slots[0],
+					    struct btrfs_file_extent_item);
+			btrfs_set_file_extent_num_bytes(leaf, fi,
+							other_end - start);
+			btrfs_set_file_extent_offset(leaf, fi,
+						     start - orig_offset);
+			btrfs_mark_buffer_dirty(leaf);
+			goto out;
+		}
+	}
+
+	while (start > key.offset || end < extent_end) {
+		if (key.offset == start)
+			split = end;
+
+		new_key.offset = split;
+		ret = btrfs_duplicate_item(trans, root, path, &new_key);
+		if (ret == -EAGAIN) {
+			btrfs_release_path(path);
+			goto again;
+		}
+		if (ret < 0) {
+			btrfs_abort_transaction(trans, root, ret);
+			goto out;
+		}
+
+		leaf = path->nodes[0];
+		fi = btrfs_item_ptr(leaf, path->slots[0] - 1,
+				    struct btrfs_file_extent_item);
+		btrfs_set_file_extent_num_bytes(leaf, fi,
+						split - key.offset);
+
+		fi = btrfs_item_ptr(leaf, path->slots[0],
+				    struct btrfs_file_extent_item);
+
+		btrfs_set_file_extent_offset(leaf, fi, split - orig_offset);
+		btrfs_set_file_extent_num_bytes(leaf, fi,
+						extent_end - split);
+		btrfs_mark_buffer_dirty(leaf);
+
+		ret = btrfs_inc_extent_ref(trans, root, bytenr, num_bytes, 0,
+					   root->root_key.objectid,
+					   ino, orig_offset, 0);
+		BUG_ON(ret); /* -ENOMEM */
+
+		if (split == start) {
+			key.offset = start;
+		} else {
+			BUG_ON(start != key.offset);
+			path->slots[0]--;
+			extent_end = end;
+		}
+		recow = 1;
+	}
+
+	other_start = end;
+	other_end = 0;
+	if (extent_mergeable(leaf, path->slots[0] + 1,
+			     ino, bytenr, orig_offset,
+			     &other_start, &other_end)) {
+		if (recow) {
+			btrfs_release_path(path);
+			goto again;
+		}
+		extent_end = other_end;
+		del_slot = path->slots[0] + 1;
+		del_nr++;
+		ret = btrfs_free_extent(trans, root, bytenr, num_bytes,
+					0, root->root_key.objectid,
+					ino, orig_offset, 0);
+		BUG_ON(ret); /* -ENOMEM */
+	}
+	other_start = 0;
+	other_end = start;
+	if (extent_mergeable(leaf, path->slots[0] - 1,
+			     ino, bytenr, orig_offset,
+			     &other_start, &other_end)) {
+		if (recow) {
+			btrfs_release_path(path);
+			goto again;
+		}
+		key.offset = other_start;
+		del_slot = path->slots[0];
+		del_nr++;
+		ret = btrfs_free_extent(trans, root, bytenr, num_bytes,
+					0, root->root_key.objectid,
+					ino, orig_offset, 0);
+		BUG_ON(ret); /* -ENOMEM */
+	}
+	if (del_nr == 0) {
+		fi = btrfs_item_ptr(leaf, path->slots[0],
+			   struct btrfs_file_extent_item);
+		btrfs_set_file_extent_type(leaf, fi,
+					   BTRFS_FILE_EXTENT_REG);
+		btrfs_mark_buffer_dirty(leaf);
+	} else {
+		fi = btrfs_item_ptr(leaf, del_slot - 1,
+			   struct btrfs_file_extent_item);
+		btrfs_set_file_extent_type(leaf, fi,
+					   BTRFS_FILE_EXTENT_REG);
+		btrfs_set_file_extent_num_bytes(leaf, fi,
+						extent_end - key.offset);
+		btrfs_mark_buffer_dirty(leaf);
+
+		ret = btrfs_del_items(trans, root, path, del_slot, del_nr);
+		if (ret < 0) {
+			btrfs_abort_transaction(trans, root, ret);
+			goto out;
+		}
+	}
+out:
+	btrfs_free_path(path);
+	return 0;
+}
+
+/*
+ * on error we return an unlocked page and the error value
+ * on success we return a locked page and 0
+ */
+static int prepare_uptodate_page(struct page *page, u64 pos,
+				 bool force_uptodate)
+{
+	int ret = 0;
+
+	if (((pos & (PAGE_CACHE_SIZE - 1)) || force_uptodate) &&
+	    !PageUptodate(page)) {
+		ret = btrfs_readpage(NULL, page);
+		if (ret)
+			return ret;
+		lock_page(page);
+		if (!PageUptodate(page)) {
+			unlock_page(page);
+			return -EIO;
+		}
+	}
+	return 0;
+}
+
+/*
+ * this gets pages into the page cache and locks them down, it also properly
+ * waits for data=ordered extents to finish before allowing the pages to be
+ * modified.
+ */
+static noinline int prepare_pages(struct btrfs_root *root, struct file *file,
+			 struct page **pages, size_t num_pages,
+			 loff_t pos, unsigned long first_index,
+			 size_t write_bytes, bool force_uptodate)
+{
+	struct extent_state *cached_state = NULL;
+	int i;
+	unsigned long index = pos >> PAGE_CACHE_SHIFT;
+	struct inode *inode = fdentry(file)->d_inode;
+	gfp_t mask = btrfs_alloc_write_mask(inode->i_mapping);
+	int err = 0;
+	int faili = 0;
+	u64 start_pos;
+	u64 last_pos;
+
+	start_pos = pos & ~((u64)root->sectorsize - 1);
+	last_pos = ((u64)index + num_pages) << PAGE_CACHE_SHIFT;
+
+again:
+	for (i = 0; i < num_pages; i++) {
+		pages[i] = find_or_create_page(inode->i_mapping, index + i,
+					       mask | __GFP_WRITE);
+		if (!pages[i]) {
+			faili = i - 1;
+			err = -ENOMEM;
+			goto fail;
+		}
+
+		if (i == 0)
+			err = prepare_uptodate_page(pages[i], pos,
+						    force_uptodate);
+		if (i == num_pages - 1)
+			err = prepare_uptodate_page(pages[i],
+						    pos + write_bytes, false);
+		if (err) {
+			page_cache_release(pages[i]);
+			faili = i - 1;
+			goto fail;
+		}
+		wait_on_page_writeback(pages[i]);
+	}
+	err = 0;
+	if (start_pos < inode->i_size) {
+		struct btrfs_ordered_extent *ordered;
+		lock_extent_bits(&BTRFS_I(inode)->io_tree,
+				 start_pos, last_pos - 1, 0, &cached_state);
+		ordered = btrfs_lookup_first_ordered_extent(inode,
+							    last_pos - 1);
+		if (ordered &&
+		    ordered->file_offset + ordered->len > start_pos &&
+		    ordered->file_offset < last_pos) {
+			btrfs_put_ordered_extent(ordered);
+			unlock_extent_cached(&BTRFS_I(inode)->io_tree,
+					     start_pos, last_pos - 1,
+					     &cached_state, GFP_NOFS);
+			for (i = 0; i < num_pages; i++) {
+				unlock_page(pages[i]);
+				page_cache_release(pages[i]);
+			}
+			btrfs_wait_ordered_range(inode, start_pos,
+						 last_pos - start_pos);
+			goto again;
+		}
+		if (ordered)
+			btrfs_put_ordered_extent(ordered);
+
+		clear_extent_bit(&BTRFS_I(inode)->io_tree, start_pos,
+				  last_pos - 1, EXTENT_DIRTY | EXTENT_DELALLOC |
+				  EXTENT_DO_ACCOUNTING, 0, 0, &cached_state,
+				  GFP_NOFS);
+		unlock_extent_cached(&BTRFS_I(inode)->io_tree,
+				     start_pos, last_pos - 1, &cached_state,
+				     GFP_NOFS);
+	}
+	for (i = 0; i < num_pages; i++) {
+		if (clear_page_dirty_for_io(pages[i]))
+			account_page_redirty(pages[i]);
+		set_page_extent_mapped(pages[i]);
+		WARN_ON(!PageLocked(pages[i]));
+	}
+	return 0;
+fail:
+	while (faili >= 0) {
+		unlock_page(pages[faili]);
+		page_cache_release(pages[faili]);
+		faili--;
+	}
+	return err;
+
+}
+
+static noinline ssize_t __btrfs_buffered_write(struct file *file,
+					       struct iov_iter *i,
+					       loff_t pos)
+{
+	struct inode *inode = fdentry(file)->d_inode;
+	struct btrfs_root *root = BTRFS_I(inode)->root;
+	struct page **pages = NULL;
+	unsigned long first_index;
+	size_t num_written = 0;
+	int nrptrs;
+	int ret = 0;
+	bool force_page_uptodate = false;
+
+	nrptrs = min((iov_iter_count(i) + PAGE_CACHE_SIZE - 1) /
+		     PAGE_CACHE_SIZE, PAGE_CACHE_SIZE /
+		     (sizeof(struct page *)));
+	nrptrs = min(nrptrs, current->nr_dirtied_pause - current->nr_dirtied);
+	nrptrs = max(nrptrs, 8);
+	pages = kmalloc(nrptrs * sizeof(struct page *), GFP_KERNEL);
+	if (!pages)
+		return -ENOMEM;
+
+	first_index = pos >> PAGE_CACHE_SHIFT;
+
+	while (iov_iter_count(i) > 0) {
+		size_t offset = pos & (PAGE_CACHE_SIZE - 1);
+		size_t write_bytes = min(iov_iter_count(i),
+					 nrptrs * (size_t)PAGE_CACHE_SIZE -
+					 offset);
+		size_t num_pages = (write_bytes + offset +
+				    PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
+		size_t dirty_pages;
+		size_t copied;
+
+		WARN_ON(num_pages > nrptrs);
+
+		/*
+		 * Fault pages before locking them in prepare_pages
+		 * to avoid recursive lock
+		 */
+		if (unlikely(iov_iter_fault_in_readable(i, write_bytes))) {
+			ret = -EFAULT;
+			break;
+		}
+
+		ret = btrfs_delalloc_reserve_space(inode,
+					num_pages << PAGE_CACHE_SHIFT);
+		if (ret)
+			break;
+
+		/*
+		 * This is going to setup the pages array with the number of
+		 * pages we want, so we don't really need to worry about the
+		 * contents of pages from loop to loop
+		 */
+		ret = prepare_pages(root, file, pages, num_pages,
+				    pos, first_index, write_bytes,
+				    force_page_uptodate);
+		if (ret) {
+			btrfs_delalloc_release_space(inode,
+					num_pages << PAGE_CACHE_SHIFT);
+			break;
+		}
+
+		copied = btrfs_copy_from_user(pos, num_pages,
+					   write_bytes, pages, i);
+
+		/*
+		 * if we have trouble faulting in the pages, fall
+		 * back to one page at a time
+		 */
+		if (copied < write_bytes)
+			nrptrs = 1;
+
+		if (copied == 0) {
+			force_page_uptodate = true;
+			dirty_pages = 0;
+		} else {
+			force_page_uptodate = false;
+			dirty_pages = (copied + offset +
+				       PAGE_CACHE_SIZE - 1) >>
+				       PAGE_CACHE_SHIFT;
+		}
+
+		/*
+		 * If we had a short copy we need to release the excess delaloc
+		 * bytes we reserved.  We need to increment outstanding_extents
+		 * because btrfs_delalloc_release_space will decrement it, but
+		 * we still have an outstanding extent for the chunk we actually
+		 * managed to copy.
+		 */
+		if (num_pages > dirty_pages) {
+			if (copied > 0) {
+				spin_lock(&BTRFS_I(inode)->lock);
+				BTRFS_I(inode)->outstanding_extents++;
+				spin_unlock(&BTRFS_I(inode)->lock);
+			}
+			btrfs_delalloc_release_space(inode,
+					(num_pages - dirty_pages) <<
+					PAGE_CACHE_SHIFT);
+		}
+
+		if (copied > 0) {
+			ret = btrfs_dirty_pages(root, inode, pages,
+						dirty_pages, pos, copied,
+						NULL);
+			if (ret) {
+				btrfs_delalloc_release_space(inode,
+					dirty_pages << PAGE_CACHE_SHIFT);
+				btrfs_drop_pages(pages, num_pages);
+				break;
+			}
+		}
+
+		btrfs_drop_pages(pages, num_pages);
+
+		cond_resched();
+
+		balance_dirty_pages_ratelimited_nr(inode->i_mapping,
+						   dirty_pages);
+		if (dirty_pages < (root->leafsize >> PAGE_CACHE_SHIFT) + 1)
+			btrfs_btree_balance_dirty(root, 1);
+
+		pos += copied;
+		num_written += copied;
+	}
+
+	kfree(pages);
+
+	return num_written ? num_written : ret;
+}
+
+static ssize_t __btrfs_direct_write(struct kiocb *iocb,
+				    const struct iovec *iov,
+				    unsigned long nr_segs, loff_t pos,
+				    loff_t *ppos, size_t count, size_t ocount)
+{
+	struct file *file = iocb->ki_filp;
+	struct inode *inode = fdentry(file)->d_inode;
+	struct iov_iter i;
+	ssize_t written;
+	ssize_t written_buffered;
+	loff_t endbyte;
+	int err;
+
+	written = generic_file_direct_write(iocb, iov, &nr_segs, pos, ppos,
+					    count, ocount);
+
+	/*
+	 * the generic O_DIRECT will update in-memory i_size after the
+	 * DIOs are done.  But our endio handlers that update the on
+	 * disk i_size never update past the in memory i_size.  So we
+	 * need one more update here to catch any additions to the
+	 * file
+	 */
+	if (inode->i_size != BTRFS_I(inode)->disk_i_size) {
+		btrfs_ordered_update_i_size(inode, inode->i_size, NULL);
+		mark_inode_dirty(inode);
+	}
+
+	if (written < 0 || written == count)
+		return written;
+
+	pos += written;
+	count -= written;
+	iov_iter_init(&i, iov, nr_segs, count, written);
+	written_buffered = __btrfs_buffered_write(file, &i, pos);
+	if (written_buffered < 0) {
+		err = written_buffered;
+		goto out;
+	}
+	endbyte = pos + written_buffered - 1;
+	err = filemap_write_and_wait_range(file->f_mapping, pos, endbyte);
+	if (err)
+		goto out;
+	written += written_buffered;
+	*ppos = pos + written_buffered;
+	invalidate_mapping_pages(file->f_mapping, pos >> PAGE_CACHE_SHIFT,
+				 endbyte >> PAGE_CACHE_SHIFT);
+out:
+	return written ? written : err;
+}
+
+static ssize_t btrfs_file_aio_write(struct kiocb *iocb,
+				    const struct iovec *iov,
+				    unsigned long nr_segs, loff_t pos)
+{
+	struct file *file = iocb->ki_filp;
+	struct inode *inode = fdentry(file)->d_inode;
+	struct btrfs_root *root = BTRFS_I(inode)->root;
+	loff_t *ppos = &iocb->ki_pos;
+	u64 start_pos;
+	ssize_t num_written = 0;
+	ssize_t err = 0;
+	size_t count, ocount;
+
+	vfs_check_frozen(inode->i_sb, SB_FREEZE_WRITE);
+
+	mutex_lock(&inode->i_mutex);
+
+	err = generic_segment_checks(iov, &nr_segs, &ocount, VERIFY_READ);
+	if (err) {
+		mutex_unlock(&inode->i_mutex);
+		goto out;
+	}
+	count = ocount;
+
+	current->backing_dev_info = inode->i_mapping->backing_dev_info;
+	err = generic_write_checks(file, &pos, &count, S_ISBLK(inode->i_mode));
+	if (err) {
+		mutex_unlock(&inode->i_mutex);
+		goto out;
+	}
+
+	if (count == 0) {
+		mutex_unlock(&inode->i_mutex);
+		goto out;
+	}
+
+	err = file_remove_suid(file);
+	if (err) {
+		mutex_unlock(&inode->i_mutex);
+		goto out;
+	}
+
+	/*
+	 * If BTRFS flips readonly due to some impossible error
+	 * (fs_info->fs_state now has BTRFS_SUPER_FLAG_ERROR),
+	 * although we have opened a file as writable, we have
+	 * to stop this write operation to ensure FS consistency.
+	 */
+	if (root->fs_info->fs_state & BTRFS_SUPER_FLAG_ERROR) {
+		mutex_unlock(&inode->i_mutex);
+		err = -EROFS;
+		goto out;
+	}
+
+	err = btrfs_update_time(file);
+	if (err) {
+		mutex_unlock(&inode->i_mutex);
+		goto out;
+	}
+	BTRFS_I(inode)->sequence++;
+
+	start_pos = round_down(pos, root->sectorsize);
+	if (start_pos > i_size_read(inode)) {
+		err = btrfs_cont_expand(inode, i_size_read(inode), start_pos);
+		if (err) {
+			mutex_unlock(&inode->i_mutex);
+			goto out;
+		}
+	}
+
+	if (unlikely(file->f_flags & O_DIRECT)) {
+		num_written = __btrfs_direct_write(iocb, iov, nr_segs,
+						   pos, ppos, count, ocount);
+	} else {
+		struct iov_iter i;
+
+		iov_iter_init(&i, iov, nr_segs, count, num_written);
+
+		num_written = __btrfs_buffered_write(file, &i, pos);
+		if (num_written > 0)
+			*ppos = pos + num_written;
+	}
+
+	mutex_unlock(&inode->i_mutex);
+
+	/*
+	 * we want to make sure fsync finds this change
+	 * but we haven't joined a transaction running right now.
+	 *
+	 * Later on, someone is sure to update the inode and get the
+	 * real transid recorded.
+	 *
+	 * We set last_trans now to the fs_info generation + 1,
+	 * this will either be one more than the running transaction
+	 * or the generation used for the next transaction if there isn't
+	 * one running right now.
+	 */
+	BTRFS_I(inode)->last_trans = root->fs_info->generation + 1;
+	if (num_written > 0 || num_written == -EIOCBQUEUED) {
+		err = generic_write_sync(file, pos, num_written);
+		if (err < 0 && num_written > 0)
+			num_written = err;
+	}
+out:
+	current->backing_dev_info = NULL;
+	return num_written ? num_written : err;
+}
+
+int btrfs_release_file(struct inode *inode, struct file *filp)
+{
+	/*
+	 * ordered_data_close is set by settattr when we are about to truncate
+	 * a file from a non-zero size to a zero size.  This tries to
+	 * flush down new bytes that may have been written if the
+	 * application were using truncate to replace a file in place.
+	 */
+	if (BTRFS_I(inode)->ordered_data_close) {
+		BTRFS_I(inode)->ordered_data_close = 0;
+		btrfs_add_ordered_operation(NULL, BTRFS_I(inode)->root, inode);
+		if (inode->i_size > BTRFS_ORDERED_OPERATIONS_FLUSH_LIMIT)
+			filemap_flush(inode->i_mapping);
+	}
+	if (filp->private_data)
+		btrfs_ioctl_trans_end(filp);
+	return 0;
+}
+
+/*
+ * fsync call for both files and directories.  This logs the inode into
+ * the tree log instead of forcing full commits whenever possible.
+ *
+ * It needs to call filemap_fdatawait so that all ordered extent updates are
+ * in the metadata btree are up to date for copying to the log.
+ *
+ * It drops the inode mutex before doing the tree log commit.  This is an
+ * important optimization for directories because holding the mutex prevents
+ * new operations on the dir while we write to disk.
+ */
+int btrfs_sync_file(struct file *file, loff_t start, loff_t end, int datasync)
+{
+	struct dentry *dentry = file->f_path.dentry;
+	struct inode *inode = dentry->d_inode;
+	struct btrfs_root *root = BTRFS_I(inode)->root;
+	int ret = 0;
+	struct btrfs_trans_handle *trans;
+
+	trace_btrfs_sync_file(file, datasync);
+
+	ret = filemap_write_and_wait_range(inode->i_mapping, start, end);
+	if (ret)
+		return ret;
+	mutex_lock(&inode->i_mutex);
+
+	/* we wait first, since the writeback may change the inode */
+	root->log_batch++;
+	btrfs_wait_ordered_range(inode, 0, (u64)-1);
+	root->log_batch++;
+
+	/*
+	 * check the transaction that last modified this inode
+	 * and see if its already been committed
+	 */
+	if (!BTRFS_I(inode)->last_trans) {
+		mutex_unlock(&inode->i_mutex);
+		goto out;
+	}
+
+	/*
+	 * if the last transaction that changed this file was before
+	 * the current transaction, we can bail out now without any
+	 * syncing
+	 */
+	smp_mb();
+	if (BTRFS_I(inode)->last_trans <=
+	    root->fs_info->last_trans_committed) {
+		BTRFS_I(inode)->last_trans = 0;
+		mutex_unlock(&inode->i_mutex);
+		goto out;
+	}
+
+	/*
+	 * ok we haven't committed the transaction yet, lets do a commit
+	 */
+	if (file->private_data)
+		btrfs_ioctl_trans_end(file);
+
+	trans = btrfs_start_transaction(root, 0);
+	if (IS_ERR(trans)) {
+		ret = PTR_ERR(trans);
+		mutex_unlock(&inode->i_mutex);
+		goto out;
+	}
+
+	ret = btrfs_log_dentry_safe(trans, root, dentry);
+	if (ret < 0) {
+		mutex_unlock(&inode->i_mutex);
+		goto out;
+	}
+
+	/* we've logged all the items and now have a consistent
+	 * version of the file in the log.  It is possible that
+	 * someone will come in and modify the file, but that's
+	 * fine because the log is consistent on disk, and we
+	 * have references to all of the file's extents
+	 *
+	 * It is possible that someone will come in and log the
+	 * file again, but that will end up using the synchronization
+	 * inside btrfs_sync_log to keep things safe.
+	 */
+	mutex_unlock(&inode->i_mutex);
+
+	if (ret != BTRFS_NO_LOG_SYNC) {
+		if (ret > 0) {
+			ret = btrfs_commit_transaction(trans, root);
+		} else {
+			ret = btrfs_sync_log(trans, root);
+			if (ret == 0)
+				ret = btrfs_end_transaction(trans, root);
+			else
+				ret = btrfs_commit_transaction(trans, root);
+		}
+	} else {
+		ret = btrfs_end_transaction(trans, root);
+	}
+out:
+	return ret > 0 ? -EIO : ret;
+}
+
+static const struct vm_operations_struct btrfs_file_vm_ops = {
+	.fault		= filemap_fault,
+	.page_mkwrite	= btrfs_page_mkwrite,
+};
+
+static int btrfs_file_mmap(struct file	*filp, struct vm_area_struct *vma)
+{
+	struct address_space *mapping = filp->f_mapping;
+
+	if (!mapping->a_ops->readpage)
+		return -ENOEXEC;
+
+	file_accessed(filp);
+	vma->vm_ops = &btrfs_file_vm_ops;
+	vma->vm_flags |= VM_CAN_NONLINEAR;
+
+	return 0;
+}
+
+static long btrfs_fallocate(struct file *file, int mode,
+			    loff_t offset, loff_t len)
+{
+	struct inode *inode = file->f_path.dentry->d_inode;
+	struct extent_state *cached_state = NULL;
+	u64 cur_offset;
+	u64 last_byte;
+	u64 alloc_start;
+	u64 alloc_end;
+	u64 alloc_hint = 0;
+	u64 locked_end;
+	u64 mask = BTRFS_I(inode)->root->sectorsize - 1;
+	struct extent_map *em;
+	int ret;
+
+	alloc_start = offset & ~mask;
+	alloc_end =  (offset + len + mask) & ~mask;
+
+	/* We only support the FALLOC_FL_KEEP_SIZE mode */
+	if (mode & ~FALLOC_FL_KEEP_SIZE)
+		return -EOPNOTSUPP;
+
+	/*
+	 * Make sure we have enough space before we do the
+	 * allocation.
+	 */
+	ret = btrfs_check_data_free_space(inode, len);
+	if (ret)
+		return ret;
+
+	/*
+	 * wait for ordered IO before we have any locks.  We'll loop again
+	 * below with the locks held.
+	 */
+	btrfs_wait_ordered_range(inode, alloc_start, alloc_end - alloc_start);
+
+	mutex_lock(&inode->i_mutex);
+	ret = inode_newsize_ok(inode, alloc_end);
+	if (ret)
+		goto out;
+
+	if (alloc_start > inode->i_size) {
+		ret = btrfs_cont_expand(inode, i_size_read(inode),
+					alloc_start);
+		if (ret)
+			goto out;
+	}
+
+	locked_end = alloc_end - 1;
+	while (1) {
+		struct btrfs_ordered_extent *ordered;
+
+		/* the extent lock is ordered inside the running
+		 * transaction
+		 */
+		lock_extent_bits(&BTRFS_I(inode)->io_tree, alloc_start,
+				 locked_end, 0, &cached_state);
+		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_cached(&BTRFS_I(inode)->io_tree,
+					     alloc_start, locked_end,
+					     &cached_state, GFP_NOFS);
+			/*
+			 * we can't wait on the range with the transaction
+			 * running or with the extent lock held
+			 */
+			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) {
+		u64 actual_end;
+
+		em = btrfs_get_extent(inode, NULL, 0, cur_offset,
+				      alloc_end - cur_offset, 0);
+		if (IS_ERR_OR_NULL(em)) {
+			if (!em)
+				ret = -ENOMEM;
+			else
+				ret = PTR_ERR(em);
+			break;
+		}
+		last_byte = min(extent_map_end(em), alloc_end);
+		actual_end = min_t(u64, extent_map_end(em), offset + len);
+		last_byte = (last_byte + mask) & ~mask;
+
+		if (em->block_start == EXTENT_MAP_HOLE ||
+		    (cur_offset >= inode->i_size &&
+		     !test_bit(EXTENT_FLAG_PREALLOC, &em->flags))) {
+			ret = btrfs_prealloc_file_range(inode, mode, cur_offset,
+							last_byte - cur_offset,
+							1 << inode->i_blkbits,
+							offset + len,
+							&alloc_hint);
+
+			if (ret < 0) {
+				free_extent_map(em);
+				break;
+			}
+		} else if (actual_end > inode->i_size &&
+			   !(mode & FALLOC_FL_KEEP_SIZE)) {
+			/*
+			 * We didn't need to allocate any more space, but we
+			 * still extended the size of the file so we need to
+			 * update i_size.
+			 */
+			inode->i_ctime = CURRENT_TIME;
+			i_size_write(inode, actual_end);
+			btrfs_ordered_update_i_size(inode, actual_end, NULL);
+		}
+		free_extent_map(em);
+
+		cur_offset = last_byte;
+		if (cur_offset >= alloc_end) {
+			ret = 0;
+			break;
+		}
+	}
+	unlock_extent_cached(&BTRFS_I(inode)->io_tree, alloc_start, locked_end,
+			     &cached_state, GFP_NOFS);
+out:
+	mutex_unlock(&inode->i_mutex);
+	/* Let go of our reservation. */
+	btrfs_free_reserved_data_space(inode, len);
+	return ret;
+}
+
+static int find_desired_extent(struct inode *inode, loff_t *offset, int origin)
+{
+	struct btrfs_root *root = BTRFS_I(inode)->root;
+	struct extent_map *em;
+	struct extent_state *cached_state = NULL;
+	u64 lockstart = *offset;
+	u64 lockend = i_size_read(inode);
+	u64 start = *offset;
+	u64 orig_start = *offset;
+	u64 len = i_size_read(inode);
+	u64 last_end = 0;
+	int ret = 0;
+
+	lockend = max_t(u64, root->sectorsize, lockend);
+	if (lockend <= lockstart)
+		lockend = lockstart + root->sectorsize;
+
+	len = lockend - lockstart + 1;
+
+	len = max_t(u64, len, root->sectorsize);
+	if (inode->i_size == 0)
+		return -ENXIO;
+
+	lock_extent_bits(&BTRFS_I(inode)->io_tree, lockstart, lockend, 0,
+			 &cached_state);
+
+	/*
+	 * Delalloc is such a pain.  If we have a hole and we have pending
+	 * delalloc for a portion of the hole we will get back a hole that
+	 * exists for the entire range since it hasn't been actually written
+	 * yet.  So to take care of this case we need to look for an extent just
+	 * before the position we want in case there is outstanding delalloc
+	 * going on here.
+	 */
+	if (origin == SEEK_HOLE && start != 0) {
+		if (start <= root->sectorsize)
+			em = btrfs_get_extent_fiemap(inode, NULL, 0, 0,
+						     root->sectorsize, 0);
+		else
+			em = btrfs_get_extent_fiemap(inode, NULL, 0,
+						     start - root->sectorsize,
+						     root->sectorsize, 0);
+		if (IS_ERR(em)) {
+			ret = PTR_ERR(em);
+			goto out;
+		}
+		last_end = em->start + em->len;
+		if (em->block_start == EXTENT_MAP_DELALLOC)
+			last_end = min_t(u64, last_end, inode->i_size);
+		free_extent_map(em);
+	}
+
+	while (1) {
+		em = btrfs_get_extent_fiemap(inode, NULL, 0, start, len, 0);
+		if (IS_ERR(em)) {
+			ret = PTR_ERR(em);
+			break;
+		}
+
+		if (em->block_start == EXTENT_MAP_HOLE) {
+			if (test_bit(EXTENT_FLAG_VACANCY, &em->flags)) {
+				if (last_end <= orig_start) {
+					free_extent_map(em);
+					ret = -ENXIO;
+					break;
+				}
+			}
+
+			if (origin == SEEK_HOLE) {
+				*offset = start;
+				free_extent_map(em);
+				break;
+			}
+		} else {
+			if (origin == SEEK_DATA) {
+				if (em->block_start == EXTENT_MAP_DELALLOC) {
+					if (start >= inode->i_size) {
+						free_extent_map(em);
+						ret = -ENXIO;
+						break;
+					}
+				}
+
+				*offset = start;
+				free_extent_map(em);
+				break;
+			}
+		}
+
+		start = em->start + em->len;
+		last_end = em->start + em->len;
+
+		if (em->block_start == EXTENT_MAP_DELALLOC)
+			last_end = min_t(u64, last_end, inode->i_size);
+
+		if (test_bit(EXTENT_FLAG_VACANCY, &em->flags)) {
+			free_extent_map(em);
+			ret = -ENXIO;
+			break;
+		}
+		free_extent_map(em);
+		cond_resched();
+	}
+	if (!ret)
+		*offset = min(*offset, inode->i_size);
+out:
+	unlock_extent_cached(&BTRFS_I(inode)->io_tree, lockstart, lockend,
+			     &cached_state, GFP_NOFS);
+	return ret;
+}
+
+static loff_t btrfs_file_llseek(struct file *file, loff_t offset, int origin)
+{
+	struct inode *inode = file->f_mapping->host;
+	int ret;
+
+	mutex_lock(&inode->i_mutex);
+	switch (origin) {
+	case SEEK_END:
+	case SEEK_CUR:
+		offset = generic_file_llseek(file, offset, origin);
+		goto out;
+	case SEEK_DATA:
+	case SEEK_HOLE:
+		if (offset >= i_size_read(inode)) {
+			mutex_unlock(&inode->i_mutex);
+			return -ENXIO;
+		}
+
+		ret = find_desired_extent(inode, &offset, origin);
+		if (ret) {
+			mutex_unlock(&inode->i_mutex);
+			return ret;
+		}
+	}
+
+	if (offset < 0 && !(file->f_mode & FMODE_UNSIGNED_OFFSET)) {
+		offset = -EINVAL;
+		goto out;
+	}
+	if (offset > inode->i_sb->s_maxbytes) {
+		offset = -EINVAL;
+		goto out;
+	}
+
+	/* Special lock needed here? */
+	if (offset != file->f_pos) {
+		file->f_pos = offset;
+		file->f_version = 0;
+	}
+out:
+	mutex_unlock(&inode->i_mutex);
+	return offset;
+}
+
+const struct file_operations btrfs_file_operations = {
+	.llseek		= btrfs_file_llseek,
+	.read		= do_sync_read,
+	.write		= do_sync_write,
+	.aio_read       = generic_file_aio_read,
+	.splice_read	= generic_file_splice_read,
+	.aio_write	= btrfs_file_aio_write,
+	.mmap		= btrfs_file_mmap,
+	.open		= generic_file_open,
+	.release	= btrfs_release_file,
+	.fsync		= btrfs_sync_file,
+	.fallocate	= btrfs_fallocate,
+	.unlocked_ioctl	= btrfs_ioctl,
+#ifdef CONFIG_COMPAT
+	.compat_ioctl	= btrfs_ioctl,
+#endif
+};