Initial import

1 files changed, 1051 insertions, 0 deletions

diff --git a/fs/btrfs/ordered-data.c b/fs/btrfs/ordered-data.c
new file mode 100644
index 000000000..760c4a5e0
--- /dev/null
+++ b/fs/btrfs/ordered-data.c
@@ -0,0 +1,1051 @@
+/*
+ * 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/slab.h>
+#include <linux/blkdev.h>
+#include <linux/writeback.h>
+#include <linux/pagevec.h>
+#include "ctree.h"
+#include "transaction.h"
+#include "btrfs_inode.h"
+#include "extent_io.h"
+#include "disk-io.h"
+
+static struct kmem_cache *btrfs_ordered_extent_cache;
+
+static u64 entry_end(struct btrfs_ordered_extent *entry)
+{
+	if (entry->file_offset + entry->len < entry->file_offset)
+		return (u64)-1;
+	return entry->file_offset + entry->len;
+}
+
+/* returns NULL if the insertion worked, or it returns the node it did find
+ * in the tree
+ */
+static struct rb_node *tree_insert(struct rb_root *root, u64 file_offset,
+				   struct rb_node *node)
+{
+	struct rb_node **p = &root->rb_node;
+	struct rb_node *parent = NULL;
+	struct btrfs_ordered_extent *entry;
+
+	while (*p) {
+		parent = *p;
+		entry = rb_entry(parent, struct btrfs_ordered_extent, rb_node);
+
+		if (file_offset < entry->file_offset)
+			p = &(*p)->rb_left;
+		else if (file_offset >= entry_end(entry))
+			p = &(*p)->rb_right;
+		else
+			return parent;
+	}
+
+	rb_link_node(node, parent, p);
+	rb_insert_color(node, root);
+	return NULL;
+}
+
+static void ordered_data_tree_panic(struct inode *inode, int errno,
+					       u64 offset)
+{
+	struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
+	btrfs_panic(fs_info, errno, "Inconsistency in ordered tree at offset "
+		    "%llu", offset);
+}
+
+/*
+ * look for a given offset in the tree, and if it can't be found return the
+ * first lesser offset
+ */
+static struct rb_node *__tree_search(struct rb_root *root, u64 file_offset,
+				     struct rb_node **prev_ret)
+{
+	struct rb_node *n = root->rb_node;
+	struct rb_node *prev = NULL;
+	struct rb_node *test;
+	struct btrfs_ordered_extent *entry;
+	struct btrfs_ordered_extent *prev_entry = NULL;
+
+	while (n) {
+		entry = rb_entry(n, struct btrfs_ordered_extent, rb_node);
+		prev = n;
+		prev_entry = entry;
+
+		if (file_offset < entry->file_offset)
+			n = n->rb_left;
+		else if (file_offset >= entry_end(entry))
+			n = n->rb_right;
+		else
+			return n;
+	}
+	if (!prev_ret)
+		return NULL;
+
+	while (prev && file_offset >= entry_end(prev_entry)) {
+		test = rb_next(prev);
+		if (!test)
+			break;
+		prev_entry = rb_entry(test, struct btrfs_ordered_extent,
+				      rb_node);
+		if (file_offset < entry_end(prev_entry))
+			break;
+
+		prev = test;
+	}
+	if (prev)
+		prev_entry = rb_entry(prev, struct btrfs_ordered_extent,
+				      rb_node);
+	while (prev && file_offset < entry_end(prev_entry)) {
+		test = rb_prev(prev);
+		if (!test)
+			break;
+		prev_entry = rb_entry(test, struct btrfs_ordered_extent,
+				      rb_node);
+		prev = test;
+	}
+	*prev_ret = prev;
+	return NULL;
+}
+
+/*
+ * helper to check if a given offset is inside a given entry
+ */
+static int offset_in_entry(struct btrfs_ordered_extent *entry, u64 file_offset)
+{
+	if (file_offset < entry->file_offset ||
+	    entry->file_offset + entry->len <= file_offset)
+		return 0;
+	return 1;
+}
+
+static int range_overlaps(struct btrfs_ordered_extent *entry, u64 file_offset,
+			  u64 len)
+{
+	if (file_offset + len <= entry->file_offset ||
+	    entry->file_offset + entry->len <= file_offset)
+		return 0;
+	return 1;
+}
+
+/*
+ * look find the first ordered struct that has this offset, otherwise
+ * the first one less than this offset
+ */
+static inline struct rb_node *tree_search(struct btrfs_ordered_inode_tree *tree,
+					  u64 file_offset)
+{
+	struct rb_root *root = &tree->tree;
+	struct rb_node *prev = NULL;
+	struct rb_node *ret;
+	struct btrfs_ordered_extent *entry;
+
+	if (tree->last) {
+		entry = rb_entry(tree->last, struct btrfs_ordered_extent,
+				 rb_node);
+		if (offset_in_entry(entry, file_offset))
+			return tree->last;
+	}
+	ret = __tree_search(root, file_offset, &prev);
+	if (!ret)
+		ret = prev;
+	if (ret)
+		tree->last = ret;
+	return ret;
+}
+
+/* allocate and add a new ordered_extent into the per-inode tree.
+ * file_offset is the logical offset in the file
+ *
+ * start is the disk block number of an extent already reserved in the
+ * extent allocation tree
+ *
+ * len is the length of the extent
+ *
+ * The tree is given a single reference on the ordered extent that was
+ * inserted.
+ */
+static int __btrfs_add_ordered_extent(struct inode *inode, u64 file_offset,
+				      u64 start, u64 len, u64 disk_len,
+				      int type, int dio, int compress_type)
+{
+	struct btrfs_root *root = BTRFS_I(inode)->root;
+	struct btrfs_ordered_inode_tree *tree;
+	struct rb_node *node;
+	struct btrfs_ordered_extent *entry;
+
+	tree = &BTRFS_I(inode)->ordered_tree;
+	entry = kmem_cache_zalloc(btrfs_ordered_extent_cache, GFP_NOFS);
+	if (!entry)
+		return -ENOMEM;
+
+	entry->file_offset = file_offset;
+	entry->start = start;
+	entry->len = len;
+	if (!(BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM) &&
+	    !(type == BTRFS_ORDERED_NOCOW))
+		entry->csum_bytes_left = disk_len;
+	entry->disk_len = disk_len;
+	entry->bytes_left = len;
+	entry->inode = igrab(inode);
+	entry->compress_type = compress_type;
+	entry->truncated_len = (u64)-1;
+	if (type != BTRFS_ORDERED_IO_DONE && type != BTRFS_ORDERED_COMPLETE)
+		set_bit(type, &entry->flags);
+
+	if (dio)
+		set_bit(BTRFS_ORDERED_DIRECT, &entry->flags);
+
+	/* one ref for the tree */
+	atomic_set(&entry->refs, 1);
+	init_waitqueue_head(&entry->wait);
+	INIT_LIST_HEAD(&entry->list);
+	INIT_LIST_HEAD(&entry->root_extent_list);
+	INIT_LIST_HEAD(&entry->work_list);
+	init_completion(&entry->completion);
+	INIT_LIST_HEAD(&entry->log_list);
+	INIT_LIST_HEAD(&entry->trans_list);
+
+	trace_btrfs_ordered_extent_add(inode, entry);
+
+	spin_lock_irq(&tree->lock);
+	node = tree_insert(&tree->tree, file_offset,
+			   &entry->rb_node);
+	if (node)
+		ordered_data_tree_panic(inode, -EEXIST, file_offset);
+	spin_unlock_irq(&tree->lock);
+
+	spin_lock(&root->ordered_extent_lock);
+	list_add_tail(&entry->root_extent_list,
+		      &root->ordered_extents);
+	root->nr_ordered_extents++;
+	if (root->nr_ordered_extents == 1) {
+		spin_lock(&root->fs_info->ordered_root_lock);
+		BUG_ON(!list_empty(&root->ordered_root));
+		list_add_tail(&root->ordered_root,
+			      &root->fs_info->ordered_roots);
+		spin_unlock(&root->fs_info->ordered_root_lock);
+	}
+	spin_unlock(&root->ordered_extent_lock);
+
+	return 0;
+}
+
+int btrfs_add_ordered_extent(struct inode *inode, u64 file_offset,
+			     u64 start, u64 len, u64 disk_len, int type)
+{
+	return __btrfs_add_ordered_extent(inode, file_offset, start, len,
+					  disk_len, type, 0,
+					  BTRFS_COMPRESS_NONE);
+}
+
+int btrfs_add_ordered_extent_dio(struct inode *inode, u64 file_offset,
+				 u64 start, u64 len, u64 disk_len, int type)
+{
+	return __btrfs_add_ordered_extent(inode, file_offset, start, len,
+					  disk_len, type, 1,
+					  BTRFS_COMPRESS_NONE);
+}
+
+int btrfs_add_ordered_extent_compress(struct inode *inode, u64 file_offset,
+				      u64 start, u64 len, u64 disk_len,
+				      int type, int compress_type)
+{
+	return __btrfs_add_ordered_extent(inode, file_offset, start, len,
+					  disk_len, type, 0,
+					  compress_type);
+}
+
+/*
+ * Add a struct btrfs_ordered_sum into the list of checksums to be inserted
+ * when an ordered extent is finished.  If the list covers more than one
+ * ordered extent, it is split across multiples.
+ */
+void btrfs_add_ordered_sum(struct inode *inode,
+			   struct btrfs_ordered_extent *entry,
+			   struct btrfs_ordered_sum *sum)
+{
+	struct btrfs_ordered_inode_tree *tree;
+
+	tree = &BTRFS_I(inode)->ordered_tree;
+	spin_lock_irq(&tree->lock);
+	list_add_tail(&sum->list, &entry->list);
+	WARN_ON(entry->csum_bytes_left < sum->len);
+	entry->csum_bytes_left -= sum->len;
+	if (entry->csum_bytes_left == 0)
+		wake_up(&entry->wait);
+	spin_unlock_irq(&tree->lock);
+}
+
+/*
+ * this is used to account for finished IO across a given range
+ * of the file.  The IO may span ordered extents.  If
+ * a given ordered_extent is completely done, 1 is returned, otherwise
+ * 0.
+ *
+ * test_and_set_bit on a flag in the struct btrfs_ordered_extent is used
+ * to make sure this function only returns 1 once for a given ordered extent.
+ *
+ * file_offset is updated to one byte past the range that is recorded as
+ * complete.  This allows you to walk forward in the file.
+ */
+int btrfs_dec_test_first_ordered_pending(struct inode *inode,
+				   struct btrfs_ordered_extent **cached,
+				   u64 *file_offset, u64 io_size, int uptodate)
+{
+	struct btrfs_ordered_inode_tree *tree;
+	struct rb_node *node;
+	struct btrfs_ordered_extent *entry = NULL;
+	int ret;
+	unsigned long flags;
+	u64 dec_end;
+	u64 dec_start;
+	u64 to_dec;
+
+	tree = &BTRFS_I(inode)->ordered_tree;
+	spin_lock_irqsave(&tree->lock, flags);
+	node = tree_search(tree, *file_offset);
+	if (!node) {
+		ret = 1;
+		goto out;
+	}
+
+	entry = rb_entry(node, struct btrfs_ordered_extent, rb_node);
+	if (!offset_in_entry(entry, *file_offset)) {
+		ret = 1;
+		goto out;
+	}
+
+	dec_start = max(*file_offset, entry->file_offset);
+	dec_end = min(*file_offset + io_size, entry->file_offset +
+		      entry->len);
+	*file_offset = dec_end;
+	if (dec_start > dec_end) {
+		btrfs_crit(BTRFS_I(inode)->root->fs_info,
+			"bad ordering dec_start %llu end %llu", dec_start, dec_end);
+	}
+	to_dec = dec_end - dec_start;
+	if (to_dec > entry->bytes_left) {
+		btrfs_crit(BTRFS_I(inode)->root->fs_info,
+			"bad ordered accounting left %llu size %llu",
+			entry->bytes_left, to_dec);
+	}
+	entry->bytes_left -= to_dec;
+	if (!uptodate)
+		set_bit(BTRFS_ORDERED_IOERR, &entry->flags);
+
+	if (entry->bytes_left == 0) {
+		ret = test_and_set_bit(BTRFS_ORDERED_IO_DONE, &entry->flags);
+		if (waitqueue_active(&entry->wait))
+			wake_up(&entry->wait);
+	} else {
+		ret = 1;
+	}
+out:
+	if (!ret && cached && entry) {
+		*cached = entry;
+		atomic_inc(&entry->refs);
+	}
+	spin_unlock_irqrestore(&tree->lock, flags);
+	return ret == 0;
+}
+
+/*
+ * this is used to account for finished IO across a given range
+ * of the file.  The IO should not span ordered extents.  If
+ * a given ordered_extent is completely done, 1 is returned, otherwise
+ * 0.
+ *
+ * test_and_set_bit on a flag in the struct btrfs_ordered_extent is used
+ * to make sure this function only returns 1 once for a given ordered extent.
+ */
+int btrfs_dec_test_ordered_pending(struct inode *inode,
+				   struct btrfs_ordered_extent **cached,
+				   u64 file_offset, u64 io_size, int uptodate)
+{
+	struct btrfs_ordered_inode_tree *tree;
+	struct rb_node *node;
+	struct btrfs_ordered_extent *entry = NULL;
+	unsigned long flags;
+	int ret;
+
+	tree = &BTRFS_I(inode)->ordered_tree;
+	spin_lock_irqsave(&tree->lock, flags);
+	if (cached && *cached) {
+		entry = *cached;
+		goto have_entry;
+	}
+
+	node = tree_search(tree, file_offset);
+	if (!node) {
+		ret = 1;
+		goto out;
+	}
+
+	entry = rb_entry(node, struct btrfs_ordered_extent, rb_node);
+have_entry:
+	if (!offset_in_entry(entry, file_offset)) {
+		ret = 1;
+		goto out;
+	}
+
+	if (io_size > entry->bytes_left) {
+		btrfs_crit(BTRFS_I(inode)->root->fs_info,
+			   "bad ordered accounting left %llu size %llu",
+		       entry->bytes_left, io_size);
+	}
+	entry->bytes_left -= io_size;
+	if (!uptodate)
+		set_bit(BTRFS_ORDERED_IOERR, &entry->flags);
+
+	if (entry->bytes_left == 0) {
+		ret = test_and_set_bit(BTRFS_ORDERED_IO_DONE, &entry->flags);
+		if (waitqueue_active(&entry->wait))
+			wake_up(&entry->wait);
+	} else {
+		ret = 1;
+	}
+out:
+	if (!ret && cached && entry) {
+		*cached = entry;
+		atomic_inc(&entry->refs);
+	}
+	spin_unlock_irqrestore(&tree->lock, flags);
+	return ret == 0;
+}
+
+/* Needs to either be called under a log transaction or the log_mutex */
+void btrfs_get_logged_extents(struct inode *inode,
+			      struct list_head *logged_list,
+			      const loff_t start,
+			      const loff_t end)
+{
+	struct btrfs_ordered_inode_tree *tree;
+	struct btrfs_ordered_extent *ordered;
+	struct rb_node *n;
+	struct rb_node *prev;
+
+	tree = &BTRFS_I(inode)->ordered_tree;
+	spin_lock_irq(&tree->lock);
+	n = __tree_search(&tree->tree, end, &prev);
+	if (!n)
+		n = prev;
+	for (; n; n = rb_prev(n)) {
+		ordered = rb_entry(n, struct btrfs_ordered_extent, rb_node);
+		if (ordered->file_offset > end)
+			continue;
+		if (entry_end(ordered) <= start)
+			break;
+		if (test_and_set_bit(BTRFS_ORDERED_LOGGED, &ordered->flags))
+			continue;
+		list_add(&ordered->log_list, logged_list);
+		atomic_inc(&ordered->refs);
+	}
+	spin_unlock_irq(&tree->lock);
+}
+
+void btrfs_put_logged_extents(struct list_head *logged_list)
+{
+	struct btrfs_ordered_extent *ordered;
+
+	while (!list_empty(logged_list)) {
+		ordered = list_first_entry(logged_list,
+					   struct btrfs_ordered_extent,
+					   log_list);
+		list_del_init(&ordered->log_list);
+		btrfs_put_ordered_extent(ordered);
+	}
+}
+
+void btrfs_submit_logged_extents(struct list_head *logged_list,
+				 struct btrfs_root *log)
+{
+	int index = log->log_transid % 2;
+
+	spin_lock_irq(&log->log_extents_lock[index]);
+	list_splice_tail(logged_list, &log->logged_list[index]);
+	spin_unlock_irq(&log->log_extents_lock[index]);
+}
+
+void btrfs_wait_logged_extents(struct btrfs_trans_handle *trans,
+			       struct btrfs_root *log, u64 transid)
+{
+	struct btrfs_ordered_extent *ordered;
+	int index = transid % 2;
+
+	spin_lock_irq(&log->log_extents_lock[index]);
+	while (!list_empty(&log->logged_list[index])) {
+		ordered = list_first_entry(&log->logged_list[index],
+					   struct btrfs_ordered_extent,
+					   log_list);
+		list_del_init(&ordered->log_list);
+		spin_unlock_irq(&log->log_extents_lock[index]);
+
+		if (!test_bit(BTRFS_ORDERED_IO_DONE, &ordered->flags) &&
+		    !test_bit(BTRFS_ORDERED_DIRECT, &ordered->flags)) {
+			struct inode *inode = ordered->inode;
+			u64 start = ordered->file_offset;
+			u64 end = ordered->file_offset + ordered->len - 1;
+
+			WARN_ON(!inode);
+			filemap_fdatawrite_range(inode->i_mapping, start, end);
+		}
+		wait_event(ordered->wait, test_bit(BTRFS_ORDERED_IO_DONE,
+						   &ordered->flags));
+
+		list_add_tail(&ordered->trans_list, &trans->ordered);
+		spin_lock_irq(&log->log_extents_lock[index]);
+	}
+	spin_unlock_irq(&log->log_extents_lock[index]);
+}
+
+void btrfs_free_logged_extents(struct btrfs_root *log, u64 transid)
+{
+	struct btrfs_ordered_extent *ordered;
+	int index = transid % 2;
+
+	spin_lock_irq(&log->log_extents_lock[index]);
+	while (!list_empty(&log->logged_list[index])) {
+		ordered = list_first_entry(&log->logged_list[index],
+					   struct btrfs_ordered_extent,
+					   log_list);
+		list_del_init(&ordered->log_list);
+		spin_unlock_irq(&log->log_extents_lock[index]);
+		btrfs_put_ordered_extent(ordered);
+		spin_lock_irq(&log->log_extents_lock[index]);
+	}
+	spin_unlock_irq(&log->log_extents_lock[index]);
+}
+
+/*
+ * used to drop a reference on an ordered extent.  This will free
+ * the extent if the last reference is dropped
+ */
+void btrfs_put_ordered_extent(struct btrfs_ordered_extent *entry)
+{
+	struct list_head *cur;
+	struct btrfs_ordered_sum *sum;
+
+	trace_btrfs_ordered_extent_put(entry->inode, entry);
+
+	if (atomic_dec_and_test(&entry->refs)) {
+		if (entry->inode)
+			btrfs_add_delayed_iput(entry->inode);
+		while (!list_empty(&entry->list)) {
+			cur = entry->list.next;
+			sum = list_entry(cur, struct btrfs_ordered_sum, list);
+			list_del(&sum->list);
+			kfree(sum);
+		}
+		kmem_cache_free(btrfs_ordered_extent_cache, entry);
+	}
+}
+
+/*
+ * remove an ordered extent from the tree.  No references are dropped
+ * and waiters are woken up.
+ */
+void btrfs_remove_ordered_extent(struct inode *inode,
+				 struct btrfs_ordered_extent *entry)
+{
+	struct btrfs_ordered_inode_tree *tree;
+	struct btrfs_root *root = BTRFS_I(inode)->root;
+	struct rb_node *node;
+
+	tree = &BTRFS_I(inode)->ordered_tree;
+	spin_lock_irq(&tree->lock);
+	node = &entry->rb_node;
+	rb_erase(node, &tree->tree);
+	if (tree->last == node)
+		tree->last = NULL;
+	set_bit(BTRFS_ORDERED_COMPLETE, &entry->flags);
+	spin_unlock_irq(&tree->lock);
+
+	spin_lock(&root->ordered_extent_lock);
+	list_del_init(&entry->root_extent_list);
+	root->nr_ordered_extents--;
+
+	trace_btrfs_ordered_extent_remove(inode, entry);
+
+	if (!root->nr_ordered_extents) {
+		spin_lock(&root->fs_info->ordered_root_lock);
+		BUG_ON(list_empty(&root->ordered_root));
+		list_del_init(&root->ordered_root);
+		spin_unlock(&root->fs_info->ordered_root_lock);
+	}
+	spin_unlock(&root->ordered_extent_lock);
+	wake_up(&entry->wait);
+}
+
+static void btrfs_run_ordered_extent_work(struct btrfs_work *work)
+{
+	struct btrfs_ordered_extent *ordered;
+
+	ordered = container_of(work, struct btrfs_ordered_extent, flush_work);
+	btrfs_start_ordered_extent(ordered->inode, ordered, 1);
+	complete(&ordered->completion);
+}
+
+/*
+ * wait for all the ordered extents in a root.  This is done when balancing
+ * space between drives.
+ */
+int btrfs_wait_ordered_extents(struct btrfs_root *root, int nr)
+{
+	struct list_head splice, works;
+	struct btrfs_ordered_extent *ordered, *next;
+	int count = 0;
+
+	INIT_LIST_HEAD(&splice);
+	INIT_LIST_HEAD(&works);
+
+	mutex_lock(&root->ordered_extent_mutex);
+	spin_lock(&root->ordered_extent_lock);
+	list_splice_init(&root->ordered_extents, &splice);
+	while (!list_empty(&splice) && nr) {
+		ordered = list_first_entry(&splice, struct btrfs_ordered_extent,
+					   root_extent_list);
+		list_move_tail(&ordered->root_extent_list,
+			       &root->ordered_extents);
+		atomic_inc(&ordered->refs);
+		spin_unlock(&root->ordered_extent_lock);
+
+		btrfs_init_work(&ordered->flush_work,
+				btrfs_flush_delalloc_helper,
+				btrfs_run_ordered_extent_work, NULL, NULL);
+		list_add_tail(&ordered->work_list, &works);
+		btrfs_queue_work(root->fs_info->flush_workers,
+				 &ordered->flush_work);
+
+		cond_resched();
+		spin_lock(&root->ordered_extent_lock);
+		if (nr != -1)
+			nr--;
+		count++;
+	}
+	list_splice_tail(&splice, &root->ordered_extents);
+	spin_unlock(&root->ordered_extent_lock);
+
+	list_for_each_entry_safe(ordered, next, &works, work_list) {
+		list_del_init(&ordered->work_list);
+		wait_for_completion(&ordered->completion);
+		btrfs_put_ordered_extent(ordered);
+		cond_resched();
+	}
+	mutex_unlock(&root->ordered_extent_mutex);
+
+	return count;
+}
+
+void btrfs_wait_ordered_roots(struct btrfs_fs_info *fs_info, int nr)
+{
+	struct btrfs_root *root;
+	struct list_head splice;
+	int done;
+
+	INIT_LIST_HEAD(&splice);
+
+	mutex_lock(&fs_info->ordered_operations_mutex);
+	spin_lock(&fs_info->ordered_root_lock);
+	list_splice_init(&fs_info->ordered_roots, &splice);
+	while (!list_empty(&splice) && nr) {
+		root = list_first_entry(&splice, struct btrfs_root,
+					ordered_root);
+		root = btrfs_grab_fs_root(root);
+		BUG_ON(!root);
+		list_move_tail(&root->ordered_root,
+			       &fs_info->ordered_roots);
+		spin_unlock(&fs_info->ordered_root_lock);
+
+		done = btrfs_wait_ordered_extents(root, nr);
+		btrfs_put_fs_root(root);
+
+		spin_lock(&fs_info->ordered_root_lock);
+		if (nr != -1) {
+			nr -= done;
+			WARN_ON(nr < 0);
+		}
+	}
+	list_splice_tail(&splice, &fs_info->ordered_roots);
+	spin_unlock(&fs_info->ordered_root_lock);
+	mutex_unlock(&fs_info->ordered_operations_mutex);
+}
+
+/*
+ * Used to start IO or wait for a given ordered extent to finish.
+ *
+ * If wait is one, this effectively waits on page writeback for all the pages
+ * in the extent, and it waits on the io completion code to insert
+ * metadata into the btree corresponding to the extent
+ */
+void btrfs_start_ordered_extent(struct inode *inode,
+				       struct btrfs_ordered_extent *entry,
+				       int wait)
+{
+	u64 start = entry->file_offset;
+	u64 end = start + entry->len - 1;
+
+	trace_btrfs_ordered_extent_start(inode, entry);
+
+	/*
+	 * pages in the range can be dirty, clean or writeback.  We
+	 * start IO on any dirty ones so the wait doesn't stall waiting
+	 * for the flusher thread to find them
+	 */
+	if (!test_bit(BTRFS_ORDERED_DIRECT, &entry->flags))
+		filemap_fdatawrite_range(inode->i_mapping, start, end);
+	if (wait) {
+		wait_event(entry->wait, test_bit(BTRFS_ORDERED_COMPLETE,
+						 &entry->flags));
+	}
+}
+
+/*
+ * Used to wait on ordered extents across a large range of bytes.
+ */
+int btrfs_wait_ordered_range(struct inode *inode, u64 start, u64 len)
+{
+	int ret = 0;
+	int ret_wb = 0;
+	u64 end;
+	u64 orig_end;
+	struct btrfs_ordered_extent *ordered;
+
+	if (start + len < start) {
+		orig_end = INT_LIMIT(loff_t);
+	} else {
+		orig_end = start + len - 1;
+		if (orig_end > INT_LIMIT(loff_t))
+			orig_end = INT_LIMIT(loff_t);
+	}
+
+	/* start IO across the range first to instantiate any delalloc
+	 * extents
+	 */
+	ret = btrfs_fdatawrite_range(inode, start, orig_end);
+	if (ret)
+		return ret;
+
+	/*
+	 * If we have a writeback error don't return immediately. Wait first
+	 * for any ordered extents that haven't completed yet. This is to make
+	 * sure no one can dirty the same page ranges and call writepages()
+	 * before the ordered extents complete - to avoid failures (-EEXIST)
+	 * when adding the new ordered extents to the ordered tree.
+	 */
+	ret_wb = filemap_fdatawait_range(inode->i_mapping, start, orig_end);
+
+	end = orig_end;
+	while (1) {
+		ordered = btrfs_lookup_first_ordered_extent(inode, end);
+		if (!ordered)
+			break;
+		if (ordered->file_offset > orig_end) {
+			btrfs_put_ordered_extent(ordered);
+			break;
+		}
+		if (ordered->file_offset + ordered->len <= start) {
+			btrfs_put_ordered_extent(ordered);
+			break;
+		}
+		btrfs_start_ordered_extent(inode, ordered, 1);
+		end = ordered->file_offset;
+		if (test_bit(BTRFS_ORDERED_IOERR, &ordered->flags))
+			ret = -EIO;
+		btrfs_put_ordered_extent(ordered);
+		if (ret || end == 0 || end == start)
+			break;
+		end--;
+	}
+	return ret_wb ? ret_wb : ret;
+}
+
+/*
+ * find an ordered extent corresponding to file_offset.  return NULL if
+ * nothing is found, otherwise take a reference on the extent and return it
+ */
+struct btrfs_ordered_extent *btrfs_lookup_ordered_extent(struct inode *inode,
+							 u64 file_offset)
+{
+	struct btrfs_ordered_inode_tree *tree;
+	struct rb_node *node;
+	struct btrfs_ordered_extent *entry = NULL;
+
+	tree = &BTRFS_I(inode)->ordered_tree;
+	spin_lock_irq(&tree->lock);
+	node = tree_search(tree, file_offset);
+	if (!node)
+		goto out;
+
+	entry = rb_entry(node, struct btrfs_ordered_extent, rb_node);
+	if (!offset_in_entry(entry, file_offset))
+		entry = NULL;
+	if (entry)
+		atomic_inc(&entry->refs);
+out:
+	spin_unlock_irq(&tree->lock);
+	return entry;
+}
+
+/* Since the DIO code tries to lock a wide area we need to look for any ordered
+ * extents that exist in the range, rather than just the start of the range.
+ */
+struct btrfs_ordered_extent *btrfs_lookup_ordered_range(struct inode *inode,
+							u64 file_offset,
+							u64 len)
+{
+	struct btrfs_ordered_inode_tree *tree;
+	struct rb_node *node;
+	struct btrfs_ordered_extent *entry = NULL;
+
+	tree = &BTRFS_I(inode)->ordered_tree;
+	spin_lock_irq(&tree->lock);
+	node = tree_search(tree, file_offset);
+	if (!node) {
+		node = tree_search(tree, file_offset + len);
+		if (!node)
+			goto out;
+	}
+
+	while (1) {
+		entry = rb_entry(node, struct btrfs_ordered_extent, rb_node);
+		if (range_overlaps(entry, file_offset, len))
+			break;
+
+		if (entry->file_offset >= file_offset + len) {
+			entry = NULL;
+			break;
+		}
+		entry = NULL;
+		node = rb_next(node);
+		if (!node)
+			break;
+	}
+out:
+	if (entry)
+		atomic_inc(&entry->refs);
+	spin_unlock_irq(&tree->lock);
+	return entry;
+}
+
+/*
+ * lookup and return any extent before 'file_offset'.  NULL is returned
+ * if none is found
+ */
+struct btrfs_ordered_extent *
+btrfs_lookup_first_ordered_extent(struct inode *inode, u64 file_offset)
+{
+	struct btrfs_ordered_inode_tree *tree;
+	struct rb_node *node;
+	struct btrfs_ordered_extent *entry = NULL;
+
+	tree = &BTRFS_I(inode)->ordered_tree;
+	spin_lock_irq(&tree->lock);
+	node = tree_search(tree, file_offset);
+	if (!node)
+		goto out;
+
+	entry = rb_entry(node, struct btrfs_ordered_extent, rb_node);
+	atomic_inc(&entry->refs);
+out:
+	spin_unlock_irq(&tree->lock);
+	return entry;
+}
+
+/*
+ * After an extent is done, call this to conditionally update the on disk
+ * i_size.  i_size is updated to cover any fully written part of the file.
+ */
+int btrfs_ordered_update_i_size(struct inode *inode, u64 offset,
+				struct btrfs_ordered_extent *ordered)
+{
+	struct btrfs_ordered_inode_tree *tree = &BTRFS_I(inode)->ordered_tree;
+	u64 disk_i_size;
+	u64 new_i_size;
+	u64 i_size = i_size_read(inode);
+	struct rb_node *node;
+	struct rb_node *prev = NULL;
+	struct btrfs_ordered_extent *test;
+	int ret = 1;
+
+	spin_lock_irq(&tree->lock);
+	if (ordered) {
+		offset = entry_end(ordered);
+		if (test_bit(BTRFS_ORDERED_TRUNCATED, &ordered->flags))
+			offset = min(offset,
+				     ordered->file_offset +
+				     ordered->truncated_len);
+	} else {
+		offset = ALIGN(offset, BTRFS_I(inode)->root->sectorsize);
+	}
+	disk_i_size = BTRFS_I(inode)->disk_i_size;
+
+	/* truncate file */
+	if (disk_i_size > i_size) {
+		BTRFS_I(inode)->disk_i_size = i_size;
+		ret = 0;
+		goto out;
+	}
+
+	/*
+	 * if the disk i_size is already at the inode->i_size, or
+	 * this ordered extent is inside the disk i_size, we're done
+	 */
+	if (disk_i_size == i_size)
+		goto out;
+
+	/*
+	 * We still need to update disk_i_size if outstanding_isize is greater
+	 * than disk_i_size.
+	 */
+	if (offset <= disk_i_size &&
+	    (!ordered || ordered->outstanding_isize <= disk_i_size))
+		goto out;
+
+	/*
+	 * walk backward from this ordered extent to disk_i_size.
+	 * if we find an ordered extent then we can't update disk i_size
+	 * yet
+	 */
+	if (ordered) {
+		node = rb_prev(&ordered->rb_node);
+	} else {
+		prev = tree_search(tree, offset);
+		/*
+		 * we insert file extents without involving ordered struct,
+		 * so there should be no ordered struct cover this offset
+		 */
+		if (prev) {
+			test = rb_entry(prev, struct btrfs_ordered_extent,
+					rb_node);
+			BUG_ON(offset_in_entry(test, offset));
+		}
+		node = prev;
+	}
+	for (; node; node = rb_prev(node)) {
+		test = rb_entry(node, struct btrfs_ordered_extent, rb_node);
+
+		/* We treat this entry as if it doesnt exist */
+		if (test_bit(BTRFS_ORDERED_UPDATED_ISIZE, &test->flags))
+			continue;
+		if (test->file_offset + test->len <= disk_i_size)
+			break;
+		if (test->file_offset >= i_size)
+			break;
+		if (entry_end(test) > disk_i_size) {
+			/*
+			 * we don't update disk_i_size now, so record this
+			 * undealt i_size. Or we will not know the real
+			 * i_size.
+			 */
+			if (test->outstanding_isize < offset)
+				test->outstanding_isize = offset;
+			if (ordered &&
+			    ordered->outstanding_isize >
+			    test->outstanding_isize)
+				test->outstanding_isize =
+						ordered->outstanding_isize;
+			goto out;
+		}
+	}
+	new_i_size = min_t(u64, offset, i_size);
+
+	/*
+	 * Some ordered extents may completed before the current one, and
+	 * we hold the real i_size in ->outstanding_isize.
+	 */
+	if (ordered && ordered->outstanding_isize > new_i_size)
+		new_i_size = min_t(u64, ordered->outstanding_isize, i_size);
+	BTRFS_I(inode)->disk_i_size = new_i_size;
+	ret = 0;
+out:
+	/*
+	 * We need to do this because we can't remove ordered extents until
+	 * after the i_disk_size has been updated and then the inode has been
+	 * updated to reflect the change, so we need to tell anybody who finds
+	 * this ordered extent that we've already done all the real work, we
+	 * just haven't completed all the other work.
+	 */
+	if (ordered)
+		set_bit(BTRFS_ORDERED_UPDATED_ISIZE, &ordered->flags);
+	spin_unlock_irq(&tree->lock);
+	return ret;
+}
+
+/*
+ * search the ordered extents for one corresponding to 'offset' and
+ * try to find a checksum.  This is used because we allow pages to
+ * be reclaimed before their checksum is actually put into the btree
+ */
+int btrfs_find_ordered_sum(struct inode *inode, u64 offset, u64 disk_bytenr,
+			   u32 *sum, int len)
+{
+	struct btrfs_ordered_sum *ordered_sum;
+	struct btrfs_ordered_extent *ordered;
+	struct btrfs_ordered_inode_tree *tree = &BTRFS_I(inode)->ordered_tree;
+	unsigned long num_sectors;
+	unsigned long i;
+	u32 sectorsize = BTRFS_I(inode)->root->sectorsize;
+	int index = 0;
+
+	ordered = btrfs_lookup_ordered_extent(inode, offset);
+	if (!ordered)
+		return 0;
+
+	spin_lock_irq(&tree->lock);
+	list_for_each_entry_reverse(ordered_sum, &ordered->list, list) {
+		if (disk_bytenr >= ordered_sum->bytenr &&
+		    disk_bytenr < ordered_sum->bytenr + ordered_sum->len) {
+			i = (disk_bytenr - ordered_sum->bytenr) >>
+			    inode->i_sb->s_blocksize_bits;
+			num_sectors = ordered_sum->len >>
+				      inode->i_sb->s_blocksize_bits;
+			num_sectors = min_t(int, len - index, num_sectors - i);
+			memcpy(sum + index, ordered_sum->sums + i,
+			       num_sectors);
+
+			index += (int)num_sectors;
+			if (index == len)
+				goto out;
+			disk_bytenr += num_sectors * sectorsize;
+		}
+	}
+out:
+	spin_unlock_irq(&tree->lock);
+	btrfs_put_ordered_extent(ordered);
+	return index;
+}
+
+int __init ordered_data_init(void)
+{
+	btrfs_ordered_extent_cache = kmem_cache_create("btrfs_ordered_extent",
+				     sizeof(struct btrfs_ordered_extent), 0,
+				     SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD,
+				     NULL);
+	if (!btrfs_ordered_extent_cache)
+		return -ENOMEM;
+
+	return 0;
+}
+
+void ordered_data_exit(void)
+{
+	if (btrfs_ordered_extent_cache)
+		kmem_cache_destroy(btrfs_ordered_extent_cache);
+}