1 files changed, 478 insertions, 284 deletions

diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index ff43802a7c88..af0359dcf337 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -59,7 +59,7 @@ void btrfs_leak_debug_check(void)
 
 	while (!list_empty(&states)) {
 		state = list_entry(states.next, struct extent_state, leak_list);
-		printk(KERN_ERR "btrfs state leak: start %llu end %llu "
+		printk(KERN_ERR "BTRFS: state leak: start %llu end %llu "
 		       "state %lu in tree %p refs %d\n",
 		       state->start, state->end, state->state, state->tree,
 		       atomic_read(&state->refs));
@@ -69,7 +69,7 @@ void btrfs_leak_debug_check(void)
 
 	while (!list_empty(&buffers)) {
 		eb = list_entry(buffers.next, struct extent_buffer, leak_list);
-		printk(KERN_ERR "btrfs buffer leak start %llu len %lu "
+		printk(KERN_ERR "BTRFS: buffer leak start %llu len %lu "
 		       "refs %d\n",
 		       eb->start, eb->len, atomic_read(&eb->refs));
 		list_del(&eb->leak_list);
@@ -77,16 +77,22 @@ void btrfs_leak_debug_check(void)
 	}
 }
 
-#define btrfs_debug_check_extent_io_range(inode, start, end)		\
-	__btrfs_debug_check_extent_io_range(__func__, (inode), (start), (end))
+#define btrfs_debug_check_extent_io_range(tree, start, end)		\
+	__btrfs_debug_check_extent_io_range(__func__, (tree), (start), (end))
 static inline void __btrfs_debug_check_extent_io_range(const char *caller,
-		struct inode *inode, u64 start, u64 end)
+		struct extent_io_tree *tree, u64 start, u64 end)
 {
-	u64 isize = i_size_read(inode);
+	struct inode *inode;
+	u64 isize;
 
+	if (!tree->mapping)
+		return;
+
+	inode = tree->mapping->host;
+	isize = i_size_read(inode);
 	if (end >= PAGE_SIZE && (end % 2) == 0 && end != isize - 1) {
 		printk_ratelimited(KERN_DEBUG
-		    "btrfs: %s: ino %llu isize %llu odd range [%llu,%llu]\n",
+		    "BTRFS: %s: ino %llu isize %llu odd range [%llu,%llu]\n",
 				caller, btrfs_ino(inode), isize, start, end);
 	}
 }
@@ -124,6 +130,8 @@ static noinline void flush_write_bio(void *data);
 static inline struct btrfs_fs_info *
 tree_fs_info(struct extent_io_tree *tree)
 {
+	if (!tree->mapping)
+		return NULL;
 	return btrfs_sb(tree->mapping->host->i_sb);
 }
 
@@ -186,11 +194,9 @@ void extent_io_tree_init(struct extent_io_tree *tree,
 			 struct address_space *mapping)
 {
 	tree->state = RB_ROOT;
-	INIT_RADIX_TREE(&tree->buffer, GFP_ATOMIC);
 	tree->ops = NULL;
 	tree->dirty_bytes = 0;
 	spin_lock_init(&tree->lock);
-	spin_lock_init(&tree->buffer_lock);
 	tree->mapping = mapping;
 }
 
@@ -223,13 +229,24 @@ void free_extent_state(struct extent_state *state)
 	}
 }
 
-static struct rb_node *tree_insert(struct rb_root *root, u64 offset,
-				   struct rb_node *node)
+static struct rb_node *tree_insert(struct rb_root *root,
+				   struct rb_node *search_start,
+				   u64 offset,
+				   struct rb_node *node,
+				   struct rb_node ***p_in,
+				   struct rb_node **parent_in)
 {
-	struct rb_node **p = &root->rb_node;
+	struct rb_node **p;
 	struct rb_node *parent = NULL;
 	struct tree_entry *entry;
 
+	if (p_in && parent_in) {
+		p = *p_in;
+		parent = *parent_in;
+		goto do_insert;
+	}
+
+	p = search_start ? &search_start : &root->rb_node;
 	while (*p) {
 		parent = *p;
 		entry = rb_entry(parent, struct tree_entry, rb_node);
@@ -242,35 +259,43 @@ static struct rb_node *tree_insert(struct rb_root *root, u64 offset,
 			return parent;
 	}
 
+do_insert:
 	rb_link_node(node, parent, p);
 	rb_insert_color(node, root);
 	return NULL;
 }
 
 static struct rb_node *__etree_search(struct extent_io_tree *tree, u64 offset,
-				     struct rb_node **prev_ret,
-				     struct rb_node **next_ret)
+				      struct rb_node **prev_ret,
+				      struct rb_node **next_ret,
+				      struct rb_node ***p_ret,
+				      struct rb_node **parent_ret)
 {
 	struct rb_root *root = &tree->state;
-	struct rb_node *n = root->rb_node;
+	struct rb_node **n = &root->rb_node;
 	struct rb_node *prev = NULL;
 	struct rb_node *orig_prev = NULL;
 	struct tree_entry *entry;
 	struct tree_entry *prev_entry = NULL;
 
-	while (n) {
-		entry = rb_entry(n, struct tree_entry, rb_node);
-		prev = n;
+	while (*n) {
+		prev = *n;
+		entry = rb_entry(prev, struct tree_entry, rb_node);
 		prev_entry = entry;
 
 		if (offset < entry->start)
-			n = n->rb_left;
+			n = &(*n)->rb_left;
 		else if (offset > entry->end)
-			n = n->rb_right;
+			n = &(*n)->rb_right;
 		else
-			return n;
+			return *n;
 	}
 
+	if (p_ret)
+		*p_ret = n;
+	if (parent_ret)
+		*parent_ret = prev;
+
 	if (prev_ret) {
 		orig_prev = prev;
 		while (prev && offset > prev_entry->end) {
@@ -292,18 +317,27 @@ static struct rb_node *__etree_search(struct extent_io_tree *tree, u64 offset,
 	return NULL;
 }
 
-static inline struct rb_node *tree_search(struct extent_io_tree *tree,
-					  u64 offset)
+static inline struct rb_node *
+tree_search_for_insert(struct extent_io_tree *tree,
+		       u64 offset,
+		       struct rb_node ***p_ret,
+		       struct rb_node **parent_ret)
 {
 	struct rb_node *prev = NULL;
 	struct rb_node *ret;
 
-	ret = __etree_search(tree, offset, &prev, NULL);
+	ret = __etree_search(tree, offset, &prev, NULL, p_ret, parent_ret);
 	if (!ret)
 		return prev;
 	return ret;
 }
 
+static inline struct rb_node *tree_search(struct extent_io_tree *tree,
+					  u64 offset)
+{
+	return tree_search_for_insert(tree, offset, NULL, NULL);
+}
+
 static void merge_cb(struct extent_io_tree *tree, struct extent_state *new,
 		     struct extent_state *other)
 {
@@ -385,23 +419,25 @@ static void set_state_bits(struct extent_io_tree *tree,
  */
 static int insert_state(struct extent_io_tree *tree,
 			struct extent_state *state, u64 start, u64 end,
+			struct rb_node ***p,
+			struct rb_node **parent,
 			unsigned long *bits)
 {
 	struct rb_node *node;
 
 	if (end < start)
-		WARN(1, KERN_ERR "btrfs end < start %llu %llu\n",
+		WARN(1, KERN_ERR "BTRFS: end < start %llu %llu\n",
 		       end, start);
 	state->start = start;
 	state->end = end;
 
 	set_state_bits(tree, state, bits);
 
-	node = tree_insert(&tree->state, end, &state->rb_node);
+	node = tree_insert(&tree->state, NULL, end, &state->rb_node, p, parent);
 	if (node) {
 		struct extent_state *found;
 		found = rb_entry(node, struct extent_state, rb_node);
-		printk(KERN_ERR "btrfs found node %llu %llu on insert of "
+		printk(KERN_ERR "BTRFS: found node %llu %llu on insert of "
 		       "%llu %llu\n",
 		       found->start, found->end, start, end);
 		return -EEXIST;
@@ -444,7 +480,8 @@ static int split_state(struct extent_io_tree *tree, struct extent_state *orig,
 	prealloc->state = orig->state;
 	orig->start = split;
 
-	node = tree_insert(&tree->state, prealloc->end, &prealloc->rb_node);
+	node = tree_insert(&tree->state, &orig->rb_node, prealloc->end,
+			   &prealloc->rb_node, NULL, NULL);
 	if (node) {
 		free_extent_state(prealloc);
 		return -EEXIST;
@@ -542,7 +579,7 @@ int clear_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
 	int err;
 	int clear = 0;
 
-	btrfs_debug_check_extent_io_range(tree->mapping->host, start, end);
+	btrfs_debug_check_extent_io_range(tree, start, end);
 
 	if (bits & EXTENT_DELALLOC)
 		bits |= EXTENT_NORESERVE;
@@ -702,7 +739,7 @@ static void wait_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
 	struct extent_state *state;
 	struct rb_node *node;
 
-	btrfs_debug_check_extent_io_range(tree->mapping->host, start, end);
+	btrfs_debug_check_extent_io_range(tree, start, end);
 
 	spin_lock(&tree->lock);
 again:
@@ -712,6 +749,7 @@ again:
 		 * our range starts
 		 */
 		node = tree_search(tree, start);
+process_node:
 		if (!node)
 			break;
 
@@ -732,7 +770,10 @@ again:
 		if (start > end)
 			break;
 
-		cond_resched_lock(&tree->lock);
+		if (!cond_resched_lock(&tree->lock)) {
+			node = rb_next(node);
+			goto process_node;
+		}
 	}
 out:
 	spin_unlock(&tree->lock);
@@ -783,11 +824,13 @@ __set_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
 	struct extent_state *state;
 	struct extent_state *prealloc = NULL;
 	struct rb_node *node;
+	struct rb_node **p;
+	struct rb_node *parent;
 	int err = 0;
 	u64 last_start;
 	u64 last_end;
 
-	btrfs_debug_check_extent_io_range(tree->mapping->host, start, end);
+	btrfs_debug_check_extent_io_range(tree, start, end);
 
 	bits |= EXTENT_FIRST_DELALLOC;
 again:
@@ -809,14 +852,16 @@ again:
 	 * this search will find all the extents that end after
 	 * our range starts.
 	 */
-	node = tree_search(tree, start);
+	node = tree_search_for_insert(tree, start, &p, &parent);
 	if (!node) {
 		prealloc = alloc_extent_state_atomic(prealloc);
 		BUG_ON(!prealloc);
-		err = insert_state(tree, prealloc, start, end, &bits);
+		err = insert_state(tree, prealloc, start, end,
+				   &p, &parent, &bits);
 		if (err)
 			extent_io_tree_panic(tree, err);
 
+		cache_state(prealloc, cached_state);
 		prealloc = NULL;
 		goto out;
 	}
@@ -919,7 +964,7 @@ hit_next:
 		 * the later extent.
 		 */
 		err = insert_state(tree, prealloc, start, this_end,
-				   &bits);
+				   NULL, NULL, &bits);
 		if (err)
 			extent_io_tree_panic(tree, err);
 
@@ -1005,11 +1050,13 @@ int convert_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
 	struct extent_state *state;
 	struct extent_state *prealloc = NULL;
 	struct rb_node *node;
+	struct rb_node **p;
+	struct rb_node *parent;
 	int err = 0;
 	u64 last_start;
 	u64 last_end;
 
-	btrfs_debug_check_extent_io_range(tree->mapping->host, start, end);
+	btrfs_debug_check_extent_io_range(tree, start, end);
 
 again:
 	if (!prealloc && (mask & __GFP_WAIT)) {
@@ -1032,17 +1079,19 @@ again:
 	 * this search will find all the extents that end after
 	 * our range starts.
 	 */
-	node = tree_search(tree, start);
+	node = tree_search_for_insert(tree, start, &p, &parent);
 	if (!node) {
 		prealloc = alloc_extent_state_atomic(prealloc);
 		if (!prealloc) {
 			err = -ENOMEM;
 			goto out;
 		}
-		err = insert_state(tree, prealloc, start, end, &bits);
-		prealloc = NULL;
+		err = insert_state(tree, prealloc, start, end,
+				   &p, &parent, &bits);
 		if (err)
 			extent_io_tree_panic(tree, err);
+		cache_state(prealloc, cached_state);
+		prealloc = NULL;
 		goto out;
 	}
 	state = rb_entry(node, struct extent_state, rb_node);
@@ -1135,7 +1184,7 @@ hit_next:
 		 * the later extent.
 		 */
 		err = insert_state(tree, prealloc, start, this_end,
-				   &bits);
+				   NULL, NULL, &bits);
 		if (err)
 			extent_io_tree_panic(tree, err);
 		cache_state(prealloc, cached_state);
@@ -1644,6 +1693,7 @@ again:
 		 * shortening the size of the delalloc range we're searching
 		 */
 		free_extent_state(cached_state);
+		cached_state = NULL;
 		if (!loops) {
 			max_bytes = PAGE_CACHE_SIZE;
 			loops = 1;
@@ -1984,7 +2034,7 @@ int repair_io_failure(struct btrfs_fs_info *fs_info, u64 start,
 	bio = btrfs_io_bio_alloc(GFP_NOFS, 1);
 	if (!bio)
 		return -EIO;
-	bio->bi_size = 0;
+	bio->bi_iter.bi_size = 0;
 	map_length = length;
 
 	ret = btrfs_map_block(fs_info, WRITE, logical,
@@ -1995,7 +2045,7 @@ int repair_io_failure(struct btrfs_fs_info *fs_info, u64 start,
 	}
 	BUG_ON(mirror_num != bbio->mirror_num);
 	sector = bbio->stripes[mirror_num-1].physical >> 9;
-	bio->bi_sector = sector;
+	bio->bi_iter.bi_sector = sector;
 	dev = bbio->stripes[mirror_num-1].dev;
 	kfree(bbio);
 	if (!dev || !dev->bdev || !dev->writeable) {
@@ -2012,9 +2062,10 @@ int repair_io_failure(struct btrfs_fs_info *fs_info, u64 start,
 		return -EIO;
 	}
 
-	printk_ratelimited_in_rcu(KERN_INFO "btrfs read error corrected: ino %lu off %llu "
-		      "(dev %s sector %llu)\n", page->mapping->host->i_ino,
-		      start, rcu_str_deref(dev->name), sector);
+	printk_ratelimited_in_rcu(KERN_INFO
+			"BTRFS: read error corrected: ino %lu off %llu "
+		    "(dev %s sector %llu)\n", page->mapping->host->i_ino,
+		    start, rcu_str_deref(dev->name), sector);
 
 	bio_put(bio);
 	return 0;
@@ -2156,7 +2207,7 @@ static int bio_readpage_error(struct bio *failed_bio, u64 phy_offset,
 			return -EIO;
 		}
 
-		if (em->start > start || em->start + em->len < start) {
+		if (em->start > start || em->start + em->len <= start) {
 			free_extent_map(em);
 			em = NULL;
 		}
@@ -2268,9 +2319,9 @@ static int bio_readpage_error(struct bio *failed_bio, u64 phy_offset,
 		return -EIO;
 	}
 	bio->bi_end_io = failed_bio->bi_end_io;
-	bio->bi_sector = failrec->logical >> 9;
+	bio->bi_iter.bi_sector = failrec->logical >> 9;
 	bio->bi_bdev = BTRFS_I(inode)->root->fs_info->fs_devices->latest_bdev;
-	bio->bi_size = 0;
+	bio->bi_iter.bi_size = 0;
 
 	btrfs_failed_bio = btrfs_io_bio(failed_bio);
 	if (btrfs_failed_bio->csum) {
@@ -2303,7 +2354,7 @@ int end_extent_writepage(struct page *page, int err, u64 start, u64 end)
 {
 	int uptodate = (err == 0);
 	struct extent_io_tree *tree;
-	int ret;
+	int ret = 0;
 
 	tree = &BTRFS_I(page->mapping->host)->io_tree;
 
@@ -2317,6 +2368,8 @@ int end_extent_writepage(struct page *page, int err, u64 start, u64 end)
 	if (!uptodate) {
 		ClearPageUptodate(page);
 		SetPageError(page);
+		ret = ret < 0 ? ret : -EIO;
+		mapping_set_error(page->mapping, ret);
 	}
 	return 0;
 }
@@ -2332,37 +2385,39 @@ int end_extent_writepage(struct page *page, int err, u64 start, u64 end)
  */
 static void end_bio_extent_writepage(struct bio *bio, int err)
 {
-	struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1;
-	struct extent_io_tree *tree;
+	struct bio_vec *bvec;
 	u64 start;
 	u64 end;
+	int i;
 
-	do {
+	bio_for_each_segment_all(bvec, bio, i) {
 		struct page *page = bvec->bv_page;
-		tree = &BTRFS_I(page->mapping->host)->io_tree;
 
 		/* We always issue full-page reads, but if some block
 		 * in a page fails to read, blk_update_request() will
 		 * advance bv_offset and adjust bv_len to compensate.
 		 * Print a warning for nonzero offsets, and an error
 		 * if they don't add up to a full page.  */
-		if (bvec->bv_offset || bvec->bv_len != PAGE_CACHE_SIZE)
-			printk("%s page write in btrfs with offset %u and length %u\n",
-			       bvec->bv_offset + bvec->bv_len != PAGE_CACHE_SIZE
-			       ? KERN_ERR "partial" : KERN_INFO "incomplete",
-			       bvec->bv_offset, bvec->bv_len);
+		if (bvec->bv_offset || bvec->bv_len != PAGE_CACHE_SIZE) {
+			if (bvec->bv_offset + bvec->bv_len != PAGE_CACHE_SIZE)
+				btrfs_err(BTRFS_I(page->mapping->host)->root->fs_info,
+				   "partial page write in btrfs with offset %u and length %u",
+					bvec->bv_offset, bvec->bv_len);
+			else
+				btrfs_info(BTRFS_I(page->mapping->host)->root->fs_info,
+				   "incomplete page write in btrfs with offset %u and "
+				   "length %u",
+					bvec->bv_offset, bvec->bv_len);
+		}
 
 		start = page_offset(page);
 		end = start + bvec->bv_offset + bvec->bv_len - 1;
 
-		if (--bvec >= bio->bi_io_vec)
-			prefetchw(&bvec->bv_page->flags);
-
 		if (end_extent_writepage(page, err, start, end))
 			continue;
 
 		end_page_writeback(page);
-	} while (bvec >= bio->bi_io_vec);
+	}
 
 	bio_put(bio);
 }
@@ -2392,9 +2447,8 @@ endio_readpage_release_extent(struct extent_io_tree *tree, u64 start, u64 len,
  */
 static void end_bio_extent_readpage(struct bio *bio, int err)
 {
+	struct bio_vec *bvec;
 	int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
-	struct bio_vec *bvec_end = bio->bi_io_vec + bio->bi_vcnt - 1;
-	struct bio_vec *bvec = bio->bi_io_vec;
 	struct btrfs_io_bio *io_bio = btrfs_io_bio(bio);
 	struct extent_io_tree *tree;
 	u64 offset = 0;
@@ -2405,16 +2459,17 @@ static void end_bio_extent_readpage(struct bio *bio, int err)
 	u64 extent_len = 0;
 	int mirror;
 	int ret;
+	int i;
 
 	if (err)
 		uptodate = 0;
 
-	do {
+	bio_for_each_segment_all(bvec, bio, i) {
 		struct page *page = bvec->bv_page;
 		struct inode *inode = page->mapping->host;
 
 		pr_debug("end_bio_extent_readpage: bi_sector=%llu, err=%d, "
-			 "mirror=%lu\n", (u64)bio->bi_sector, err,
+			 "mirror=%lu\n", (u64)bio->bi_iter.bi_sector, err,
 			 io_bio->mirror_num);
 		tree = &BTRFS_I(inode)->io_tree;
 
@@ -2423,19 +2478,22 @@ static void end_bio_extent_readpage(struct bio *bio, int err)
 		 * advance bv_offset and adjust bv_len to compensate.
 		 * Print a warning for nonzero offsets, and an error
 		 * if they don't add up to a full page.  */
-		if (bvec->bv_offset || bvec->bv_len != PAGE_CACHE_SIZE)
-			printk("%s page read in btrfs with offset %u and length %u\n",
-			       bvec->bv_offset + bvec->bv_len != PAGE_CACHE_SIZE
-			       ? KERN_ERR "partial" : KERN_INFO "incomplete",
-			       bvec->bv_offset, bvec->bv_len);
+		if (bvec->bv_offset || bvec->bv_len != PAGE_CACHE_SIZE) {
+			if (bvec->bv_offset + bvec->bv_len != PAGE_CACHE_SIZE)
+				btrfs_err(BTRFS_I(page->mapping->host)->root->fs_info,
+				   "partial page read in btrfs with offset %u and length %u",
+					bvec->bv_offset, bvec->bv_len);
+			else
+				btrfs_info(BTRFS_I(page->mapping->host)->root->fs_info,
+				   "incomplete page read in btrfs with offset %u and "
+				   "length %u",
+					bvec->bv_offset, bvec->bv_len);
+		}
 
 		start = page_offset(page);
 		end = start + bvec->bv_offset + bvec->bv_len - 1;
 		len = bvec->bv_len;
 
-		if (++bvec <= bvec_end)
-			prefetchw(&bvec->bv_page->flags);
-
 		mirror = io_bio->mirror_num;
 		if (likely(uptodate && tree->ops &&
 			   tree->ops->readpage_end_io_hook)) {
@@ -2474,6 +2532,7 @@ static void end_bio_extent_readpage(struct bio *bio, int err)
 					test_bit(BIO_UPTODATE, &bio->bi_flags);
 				if (err)
 					uptodate = 0;
+				offset += len;
 				continue;
 			}
 		}
@@ -2516,7 +2575,7 @@ readpage_ok:
 			extent_start = start;
 			extent_len = end + 1 - start;
 		}
-	} while (bvec <= bvec_end);
+	}
 
 	if (extent_len)
 		endio_readpage_release_extent(tree, extent_start, extent_len,
@@ -2547,9 +2606,8 @@ btrfs_bio_alloc(struct block_device *bdev, u64 first_sector, int nr_vecs,
 	}
 
 	if (bio) {
-		bio->bi_size = 0;
 		bio->bi_bdev = bdev;
-		bio->bi_sector = first_sector;
+		bio->bi_iter.bi_sector = first_sector;
 		btrfs_bio = btrfs_io_bio(bio);
 		btrfs_bio->csum = NULL;
 		btrfs_bio->csum_allocated = NULL;
@@ -2643,7 +2701,7 @@ static int submit_extent_page(int rw, struct extent_io_tree *tree,
 	if (bio_ret && *bio_ret) {
 		bio = *bio_ret;
 		if (old_compressed)
-			contig = bio->bi_sector == sector;
+			contig = bio->bi_iter.bi_sector == sector;
 		else
 			contig = bio_end_sector(bio) == sector;
 
@@ -2710,7 +2768,7 @@ __get_extent_map(struct inode *inode, struct page *page, size_t pg_offset,
 
 	if (em_cached && *em_cached) {
 		em = *em_cached;
-		if (em->in_tree && start >= em->start &&
+		if (extent_map_in_tree(em) && start >= em->start &&
 		    start < extent_map_end(em)) {
 			atomic_inc(&em->refs);
 			return em;
@@ -3044,143 +3102,130 @@ static noinline void update_nr_written(struct page *page,
 }
 
 /*
- * the writepage semantics are similar to regular writepage.  extent
- * records are inserted to lock ranges in the tree, and as dirty areas
- * are found, they are marked writeback.  Then the lock bits are removed
- * and the end_io handler clears the writeback ranges
+ * helper for __extent_writepage, doing all of the delayed allocation setup.
+ *
+ * This returns 1 if our fill_delalloc function did all the work required
+ * to write the page (copy into inline extent).  In this case the IO has
+ * been started and the page is already unlocked.
+ *
+ * This returns 0 if all went well (page still locked)
+ * This returns < 0 if there were errors (page still locked)
  */
-static int __extent_writepage(struct page *page, struct writeback_control *wbc,
-			      void *data)
+static noinline_for_stack int writepage_delalloc(struct inode *inode,
+			      struct page *page, struct writeback_control *wbc,
+			      struct extent_page_data *epd,
+			      u64 delalloc_start,
+			      unsigned long *nr_written)
+{
+	struct extent_io_tree *tree = epd->tree;
+	u64 page_end = delalloc_start + PAGE_CACHE_SIZE - 1;
+	u64 nr_delalloc;
+	u64 delalloc_to_write = 0;
+	u64 delalloc_end = 0;
+	int ret;
+	int page_started = 0;
+
+	if (epd->extent_locked || !tree->ops || !tree->ops->fill_delalloc)
+		return 0;
+
+	while (delalloc_end < page_end) {
+		nr_delalloc = find_lock_delalloc_range(inode, tree,
+					       page,
+					       &delalloc_start,
+					       &delalloc_end,
+					       128 * 1024 * 1024);
+		if (nr_delalloc == 0) {
+			delalloc_start = delalloc_end + 1;
+			continue;
+		}
+		ret = tree->ops->fill_delalloc(inode, page,
+					       delalloc_start,
+					       delalloc_end,
+					       &page_started,
+					       nr_written);
+		/* File system has been set read-only */
+		if (ret) {
+			SetPageError(page);
+			/* fill_delalloc should be return < 0 for error
+			 * but just in case, we use > 0 here meaning the
+			 * IO is started, so we don't want to return > 0
+			 * unless things are going well.
+			 */
+			ret = ret < 0 ? ret : -EIO;
+			goto done;
+		}
+		/*
+		 * delalloc_end is already one less than the total
+		 * length, so we don't subtract one from
+		 * PAGE_CACHE_SIZE
+		 */
+		delalloc_to_write += (delalloc_end - delalloc_start +
+				      PAGE_CACHE_SIZE) >>
+				      PAGE_CACHE_SHIFT;
+		delalloc_start = delalloc_end + 1;
+	}
+	if (wbc->nr_to_write < delalloc_to_write) {
+		int thresh = 8192;
+
+		if (delalloc_to_write < thresh * 2)
+			thresh = delalloc_to_write;
+		wbc->nr_to_write = min_t(u64, delalloc_to_write,
+					 thresh);
+	}
+
+	/* did the fill delalloc function already unlock and start
+	 * the IO?
+	 */
+	if (page_started) {
+		/*
+		 * we've unlocked the page, so we can't update
+		 * the mapping's writeback index, just update
+		 * nr_to_write.
+		 */
+		wbc->nr_to_write -= *nr_written;
+		return 1;
+	}
+
+	ret = 0;
+
+done:
+	return ret;
+}
+
+/*
+ * helper for __extent_writepage.  This calls the writepage start hooks,
+ * and does the loop to map the page into extents and bios.
+ *
+ * We return 1 if the IO is started and the page is unlocked,
+ * 0 if all went well (page still locked)
+ * < 0 if there were errors (page still locked)
+ */
+static noinline_for_stack int __extent_writepage_io(struct inode *inode,
+				 struct page *page,
+				 struct writeback_control *wbc,
+				 struct extent_page_data *epd,
+				 loff_t i_size,
+				 unsigned long nr_written,
+				 int write_flags, int *nr_ret)
 {
-	struct inode *inode = page->mapping->host;
-	struct extent_page_data *epd = data;
 	struct extent_io_tree *tree = epd->tree;
 	u64 start = page_offset(page);
-	u64 delalloc_start;
 	u64 page_end = start + PAGE_CACHE_SIZE - 1;
 	u64 end;
 	u64 cur = start;
 	u64 extent_offset;
-	u64 last_byte = i_size_read(inode);
 	u64 block_start;
 	u64 iosize;
 	sector_t sector;
 	struct extent_state *cached_state = NULL;
 	struct extent_map *em;
 	struct block_device *bdev;
-	int ret;
-	int nr = 0;
 	size_t pg_offset = 0;
 	size_t blocksize;
-	loff_t i_size = i_size_read(inode);
-	unsigned long end_index = i_size >> PAGE_CACHE_SHIFT;
-	u64 nr_delalloc;
-	u64 delalloc_end;
-	int page_started;
-	int compressed;
-	int write_flags;
-	unsigned long nr_written = 0;
-	bool fill_delalloc = true;
-
-	if (wbc->sync_mode == WB_SYNC_ALL)
-		write_flags = WRITE_SYNC;
-	else
-		write_flags = WRITE;
-
-	trace___extent_writepage(page, inode, wbc);
-
-	WARN_ON(!PageLocked(page));
-
-	ClearPageError(page);
-
-	pg_offset = i_size & (PAGE_CACHE_SIZE - 1);
-	if (page->index > end_index ||
-	   (page->index == end_index && !pg_offset)) {
-		page->mapping->a_ops->invalidatepage(page, 0, PAGE_CACHE_SIZE);
-		unlock_page(page);
-		return 0;
-	}
-
-	if (page->index == end_index) {
-		char *userpage;
-
-		userpage = kmap_atomic(page);
-		memset(userpage + pg_offset, 0,
-		       PAGE_CACHE_SIZE - pg_offset);
-		kunmap_atomic(userpage);
-		flush_dcache_page(page);
-	}
-	pg_offset = 0;
-
-	set_page_extent_mapped(page);
-
-	if (!tree->ops || !tree->ops->fill_delalloc)
-		fill_delalloc = false;
-
-	delalloc_start = start;
-	delalloc_end = 0;
-	page_started = 0;
-	if (!epd->extent_locked && fill_delalloc) {
-		u64 delalloc_to_write = 0;
-		/*
-		 * make sure the wbc mapping index is at least updated
-		 * to this page.
-		 */
-		update_nr_written(page, wbc, 0);
-
-		while (delalloc_end < page_end) {
-			nr_delalloc = find_lock_delalloc_range(inode, tree,
-						       page,
-						       &delalloc_start,
-						       &delalloc_end,
-						       128 * 1024 * 1024);
-			if (nr_delalloc == 0) {
-				delalloc_start = delalloc_end + 1;
-				continue;
-			}
-			ret = tree->ops->fill_delalloc(inode, page,
-						       delalloc_start,
-						       delalloc_end,
-						       &page_started,
-						       &nr_written);
-			/* File system has been set read-only */
-			if (ret) {
-				SetPageError(page);
-				goto done;
-			}
-			/*
-			 * delalloc_end is already one less than the total
-			 * length, so we don't subtract one from
-			 * PAGE_CACHE_SIZE
-			 */
-			delalloc_to_write += (delalloc_end - delalloc_start +
-					      PAGE_CACHE_SIZE) >>
-					      PAGE_CACHE_SHIFT;
-			delalloc_start = delalloc_end + 1;
-		}
-		if (wbc->nr_to_write < delalloc_to_write) {
-			int thresh = 8192;
-
-			if (delalloc_to_write < thresh * 2)
-				thresh = delalloc_to_write;
-			wbc->nr_to_write = min_t(u64, delalloc_to_write,
-						 thresh);
-		}
+	int ret = 0;
+	int nr = 0;
+	bool compressed;
 
-		/* did the fill delalloc function already unlock and start
-		 * the IO?
-		 */
-		if (page_started) {
-			ret = 0;
-			/*
-			 * we've unlocked the page, so we can't update
-			 * the mapping's writeback index, just update
-			 * nr_to_write.
-			 */
-			wbc->nr_to_write -= nr_written;
-			goto done_unlocked;
-		}
-	}
 	if (tree->ops && tree->ops->writepage_start_hook) {
 		ret = tree->ops->writepage_start_hook(page, start,
 						      page_end);
@@ -3190,9 +3235,10 @@ static int __extent_writepage(struct page *page, struct writeback_control *wbc,
 				wbc->pages_skipped++;
 			else
 				redirty_page_for_writepage(wbc, page);
+
 			update_nr_written(page, wbc, nr_written);
 			unlock_page(page);
-			ret = 0;
+			ret = 1;
 			goto done_unlocked;
 		}
 	}
@@ -3204,7 +3250,7 @@ static int __extent_writepage(struct page *page, struct writeback_control *wbc,
 	update_nr_written(page, wbc, nr_written + 1);
 
 	end = page_end;
-	if (last_byte <= start) {
+	if (i_size <= start) {
 		if (tree->ops && tree->ops->writepage_end_io_hook)
 			tree->ops->writepage_end_io_hook(page, start,
 							 page_end, NULL, 1);
@@ -3214,7 +3260,8 @@ static int __extent_writepage(struct page *page, struct writeback_control *wbc,
 	blocksize = inode->i_sb->s_blocksize;
 
 	while (cur <= end) {
-		if (cur >= last_byte) {
+		u64 em_end;
+		if (cur >= i_size) {
 			if (tree->ops && tree->ops->writepage_end_io_hook)
 				tree->ops->writepage_end_io_hook(page, cur,
 							 page_end, NULL, 1);
@@ -3224,13 +3271,15 @@ static int __extent_writepage(struct page *page, struct writeback_control *wbc,
 				     end - cur + 1, 1);
 		if (IS_ERR_OR_NULL(em)) {
 			SetPageError(page);
+			ret = PTR_ERR_OR_ZERO(em);
 			break;
 		}
 
 		extent_offset = cur - em->start;
-		BUG_ON(extent_map_end(em) <= cur);
+		em_end = extent_map_end(em);
+		BUG_ON(em_end <= cur);
 		BUG_ON(end < cur);
-		iosize = min(extent_map_end(em) - cur, end - cur + 1);
+		iosize = min(em_end - cur, end - cur + 1);
 		iosize = ALIGN(iosize, blocksize);
 		sector = (em->block_start + extent_offset) >> 9;
 		bdev = em->bdev;
@@ -3266,13 +3315,6 @@ static int __extent_writepage(struct page *page, struct writeback_control *wbc,
 			pg_offset += iosize;
 			continue;
 		}
-		/* leave this out until we have a page_mkwrite call */
-		if (0 && !test_range_bit(tree, cur, cur + iosize - 1,
-				   EXTENT_DIRTY, 0, NULL)) {
-			cur = cur + iosize;
-			pg_offset += iosize;
-			continue;
-		}
 
 		if (tree->ops && tree->ops->writepage_io_hook) {
 			ret = tree->ops->writepage_io_hook(page, cur,
@@ -3283,12 +3325,12 @@ static int __extent_writepage(struct page *page, struct writeback_control *wbc,
 		if (ret) {
 			SetPageError(page);
 		} else {
-			unsigned long max_nr = end_index + 1;
+			unsigned long max_nr = (i_size >> PAGE_CACHE_SHIFT) + 1;
 
 			set_range_writeback(tree, cur, cur + iosize - 1);
 			if (!PageWriteback(page)) {
-				printk(KERN_ERR "btrfs warning page %lu not "
-				       "writeback, cur %llu end %llu\n",
+				btrfs_err(BTRFS_I(inode)->root->fs_info,
+					   "page %lu not writeback, cur %llu end %llu",
 				       page->index, cur, end);
 			}
 
@@ -3305,35 +3347,107 @@ static int __extent_writepage(struct page *page, struct writeback_control *wbc,
 		nr++;
 	}
 done:
-	if (nr == 0) {
-		/* make sure the mapping tag for page dirty gets cleared */
-		set_page_writeback(page);
-		end_page_writeback(page);
-	}
-	unlock_page(page);
+	*nr_ret = nr;
 
 done_unlocked:
 
 	/* drop our reference on any cached states */
 	free_extent_state(cached_state);
-	return 0;
+	return ret;
 }
 
-static int eb_wait(void *word)
+/*
+ * the writepage semantics are similar to regular writepage.  extent
+ * records are inserted to lock ranges in the tree, and as dirty areas
+ * are found, they are marked writeback.  Then the lock bits are removed
+ * and the end_io handler clears the writeback ranges
+ */
+static int __extent_writepage(struct page *page, struct writeback_control *wbc,
+			      void *data)
 {
-	io_schedule();
+	struct inode *inode = page->mapping->host;
+	struct extent_page_data *epd = data;
+	u64 start = page_offset(page);
+	u64 page_end = start + PAGE_CACHE_SIZE - 1;
+	int ret;
+	int nr = 0;
+	size_t pg_offset = 0;
+	loff_t i_size = i_size_read(inode);
+	unsigned long end_index = i_size >> PAGE_CACHE_SHIFT;
+	int write_flags;
+	unsigned long nr_written = 0;
+
+	if (wbc->sync_mode == WB_SYNC_ALL)
+		write_flags = WRITE_SYNC;
+	else
+		write_flags = WRITE;
+
+	trace___extent_writepage(page, inode, wbc);
+
+	WARN_ON(!PageLocked(page));
+
+	ClearPageError(page);
+
+	pg_offset = i_size & (PAGE_CACHE_SIZE - 1);
+	if (page->index > end_index ||
+	   (page->index == end_index && !pg_offset)) {
+		page->mapping->a_ops->invalidatepage(page, 0, PAGE_CACHE_SIZE);
+		unlock_page(page);
+		return 0;
+	}
+
+	if (page->index == end_index) {
+		char *userpage;
+
+		userpage = kmap_atomic(page);
+		memset(userpage + pg_offset, 0,
+		       PAGE_CACHE_SIZE - pg_offset);
+		kunmap_atomic(userpage);
+		flush_dcache_page(page);
+	}
+
+	pg_offset = 0;
+
+	set_page_extent_mapped(page);
+
+	ret = writepage_delalloc(inode, page, wbc, epd, start, &nr_written);
+	if (ret == 1)
+		goto done_unlocked;
+	if (ret)
+		goto done;
+
+	ret = __extent_writepage_io(inode, page, wbc, epd,
+				    i_size, nr_written, write_flags, &nr);
+	if (ret == 1)
+		goto done_unlocked;
+
+done:
+	if (nr == 0) {
+		/* make sure the mapping tag for page dirty gets cleared */
+		set_page_writeback(page);
+		end_page_writeback(page);
+	}
+	if (PageError(page)) {
+		ret = ret < 0 ? ret : -EIO;
+		end_extent_writepage(page, ret, start, page_end);
+	}
+	unlock_page(page);
+	return ret;
+
+done_unlocked:
 	return 0;
 }
 
 void wait_on_extent_buffer_writeback(struct extent_buffer *eb)
 {
-	wait_on_bit(&eb->bflags, EXTENT_BUFFER_WRITEBACK, eb_wait,
-		    TASK_UNINTERRUPTIBLE);
+	wait_on_bit_io(&eb->bflags, EXTENT_BUFFER_WRITEBACK,
+		       TASK_UNINTERRUPTIBLE);
 }
 
-static int lock_extent_buffer_for_io(struct extent_buffer *eb,
-				     struct btrfs_fs_info *fs_info,
-				     struct extent_page_data *epd)
+static noinline_for_stack int
+lock_extent_buffer_for_io(struct extent_buffer *eb,
+			  struct btrfs_fs_info *fs_info,
+			  struct extent_page_data *epd)
 {
 	unsigned long i, num_pages;
 	int flush = 0;
@@ -3404,26 +3518,24 @@ static int lock_extent_buffer_for_io(struct extent_buffer *eb,
 static void end_extent_buffer_writeback(struct extent_buffer *eb)
 {
 	clear_bit(EXTENT_BUFFER_WRITEBACK, &eb->bflags);
-	smp_mb__after_clear_bit();
+	smp_mb__after_atomic();
 	wake_up_bit(&eb->bflags, EXTENT_BUFFER_WRITEBACK);
 }
 
 static void end_bio_extent_buffer_writepage(struct bio *bio, int err)
 {
-	int uptodate = err == 0;
-	struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1;
+	struct bio_vec *bvec;
 	struct extent_buffer *eb;
-	int done;
+	int i, done;
 
-	do {
+	bio_for_each_segment_all(bvec, bio, i) {
 		struct page *page = bvec->bv_page;
 
-		bvec--;
 		eb = (struct extent_buffer *)page->private;
 		BUG_ON(!eb);
 		done = atomic_dec_and_test(&eb->io_pages);
 
-		if (!uptodate || test_bit(EXTENT_BUFFER_IOERR, &eb->bflags)) {
+		if (err || test_bit(EXTENT_BUFFER_IOERR, &eb->bflags)) {
 			set_bit(EXTENT_BUFFER_IOERR, &eb->bflags);
 			ClearPageUptodate(page);
 			SetPageError(page);
@@ -3435,18 +3547,18 @@ static void end_bio_extent_buffer_writepage(struct bio *bio, int err)
 			continue;
 
 		end_extent_buffer_writeback(eb);
-	} while (bvec >= bio->bi_io_vec);
+	}
 
 	bio_put(bio);
-
 }
 
-static int write_one_eb(struct extent_buffer *eb,
+static noinline_for_stack int write_one_eb(struct extent_buffer *eb,
 			struct btrfs_fs_info *fs_info,
 			struct writeback_control *wbc,
 			struct extent_page_data *epd)
 {
 	struct block_device *bdev = fs_info->fs_devices->latest_bdev;
+	struct extent_io_tree *tree = &BTRFS_I(fs_info->btree_inode)->io_tree;
 	u64 offset = eb->start;
 	unsigned long i, num_pages;
 	unsigned long bio_flags = 0;
@@ -3464,7 +3576,7 @@ static int write_one_eb(struct extent_buffer *eb,
 
 		clear_page_dirty_for_io(p);
 		set_page_writeback(p);
-		ret = submit_extent_page(rw, eb->tree, p, offset >> 9,
+		ret = submit_extent_page(rw, tree, p, offset >> 9,
 					 PAGE_CACHE_SIZE, 0, bdev, &epd->bio,
 					 -1, end_bio_extent_buffer_writepage,
 					 0, epd->bio_flags, bio_flags);
@@ -3638,6 +3750,7 @@ static int extent_write_cache_pages(struct extent_io_tree *tree,
 	struct inode *inode = mapping->host;
 	int ret = 0;
 	int done = 0;
+	int err = 0;
 	int nr_to_write_done = 0;
 	struct pagevec pvec;
 	int nr_pages;
@@ -3724,8 +3837,8 @@ retry:
 				unlock_page(page);
 				ret = 0;
 			}
-			if (ret)
-				done = 1;
+			if (!err && ret < 0)
+				err = ret;
 
 			/*
 			 * the filesystem may choose to bump up nr_to_write.
@@ -3737,7 +3850,7 @@ retry:
 		pagevec_release(&pvec);
 		cond_resched();
 	}
-	if (!scanned && !done) {
+	if (!scanned && !done && !err) {
 		/*
 		 * We hit the last page and there is more work to be done: wrap
 		 * back to the start of the file
@@ -3747,7 +3860,7 @@ retry:
 		goto retry;
 	}
 	btrfs_add_delayed_iput(inode);
-	return ret;
+	return err;
 }
 
 static void flush_epd_write_bio(struct extent_page_data *epd)
@@ -4082,12 +4195,10 @@ int extent_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
 	struct extent_map *em = NULL;
 	struct extent_state *cached_state = NULL;
 	struct btrfs_path *path;
-	struct btrfs_file_extent_item *item;
 	int end = 0;
 	u64 em_start = 0;
 	u64 em_len = 0;
 	u64 em_end = 0;
-	unsigned long emflags;
 
 	if (len == 0)
 		return -EINVAL;
@@ -4097,8 +4208,8 @@ int extent_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
 		return -ENOMEM;
 	path->leave_spinning = 1;
 
-	start = ALIGN(start, BTRFS_I(inode)->root->sectorsize);
-	len = ALIGN(len, BTRFS_I(inode)->root->sectorsize);
+	start = round_down(start, BTRFS_I(inode)->root->sectorsize);
+	len = round_up(max, BTRFS_I(inode)->root->sectorsize) - start;
 
 	/*
 	 * lookup the last file extent.  We're not using i_size here
@@ -4112,8 +4223,6 @@ int extent_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
 	}
 	WARN_ON(!ret);
 	path->slots[0]--;
-	item = btrfs_item_ptr(path->nodes[0], path->slots[0],
-			      struct btrfs_file_extent_item);
 	btrfs_item_key_to_cpu(path->nodes[0], &found_key, path->slots[0]);
 	found_type = btrfs_key_type(&found_key);
 
@@ -4181,7 +4290,6 @@ int extent_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
 			offset_in_extent = em_start - em->start;
 		em_end = extent_map_end(em);
 		em_len = em_end - em_start;
-		emflags = em->flags;
 		disko = 0;
 		flags = 0;
 
@@ -4263,7 +4371,7 @@ static void __free_extent_buffer(struct extent_buffer *eb)
 	kmem_cache_free(extent_buffer_cache, eb);
 }
 
-static int extent_buffer_under_io(struct extent_buffer *eb)
+int extent_buffer_under_io(struct extent_buffer *eb)
 {
 	return (atomic_read(&eb->io_pages) ||
 		test_bit(EXTENT_BUFFER_WRITEBACK, &eb->bflags) ||
@@ -4333,10 +4441,9 @@ static inline void btrfs_release_extent_buffer(struct extent_buffer *eb)
 	__free_extent_buffer(eb);
 }
 
-static struct extent_buffer *__alloc_extent_buffer(struct extent_io_tree *tree,
-						   u64 start,
-						   unsigned long len,
-						   gfp_t mask)
+static struct extent_buffer *
+__alloc_extent_buffer(struct btrfs_fs_info *fs_info, u64 start,
+		      unsigned long len, gfp_t mask)
 {
 	struct extent_buffer *eb = NULL;
 
@@ -4345,7 +4452,7 @@ static struct extent_buffer *__alloc_extent_buffer(struct extent_io_tree *tree,
 		return NULL;
 	eb->start = start;
 	eb->len = len;
-	eb->tree = tree;
+	eb->fs_info = fs_info;
 	eb->bflags = 0;
 	rwlock_init(&eb->lock);
 	atomic_set(&eb->write_locks, 0);
@@ -4464,7 +4571,8 @@ static void check_buffer_tree_ref(struct extent_buffer *eb)
 	spin_unlock(&eb->refs_lock);
 }
 
-static void mark_extent_buffer_accessed(struct extent_buffer *eb)
+static void mark_extent_buffer_accessed(struct extent_buffer *eb,
+		struct page *accessed)
 {
 	unsigned long num_pages, i;
 
@@ -4473,20 +4581,22 @@ static void mark_extent_buffer_accessed(struct extent_buffer *eb)
 	num_pages = num_extent_pages(eb->start, eb->len);
 	for (i = 0; i < num_pages; i++) {
 		struct page *p = extent_buffer_page(eb, i);
-		mark_page_accessed(p);
+		if (p != accessed)
+			mark_page_accessed(p);
 	}
 }
 
-struct extent_buffer *find_extent_buffer(struct extent_io_tree *tree,
-					 		u64 start)
+struct extent_buffer *find_extent_buffer(struct btrfs_fs_info *fs_info,
+					 u64 start)
 {
 	struct extent_buffer *eb;
 
 	rcu_read_lock();
-	eb = radix_tree_lookup(&tree->buffer, start >> PAGE_CACHE_SHIFT);
+	eb = radix_tree_lookup(&fs_info->buffer_radix,
+			       start >> PAGE_CACHE_SHIFT);
 	if (eb && atomic_inc_not_zero(&eb->refs)) {
 		rcu_read_unlock();
-		mark_extent_buffer_accessed(eb);
+		mark_extent_buffer_accessed(eb, NULL);
 		return eb;
 	}
 	rcu_read_unlock();
@@ -4494,7 +4604,54 @@ struct extent_buffer *find_extent_buffer(struct extent_io_tree *tree,
 	return NULL;
 }
 
-struct extent_buffer *alloc_extent_buffer(struct extent_io_tree *tree,
+#ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
+struct extent_buffer *alloc_test_extent_buffer(struct btrfs_fs_info *fs_info,
+					       u64 start, unsigned long len)
+{
+	struct extent_buffer *eb, *exists = NULL;
+	int ret;
+
+	eb = find_extent_buffer(fs_info, start);
+	if (eb)
+		return eb;
+	eb = alloc_dummy_extent_buffer(start, len);
+	if (!eb)
+		return NULL;
+	eb->fs_info = fs_info;
+again:
+	ret = radix_tree_preload(GFP_NOFS & ~__GFP_HIGHMEM);
+	if (ret)
+		goto free_eb;
+	spin_lock(&fs_info->buffer_lock);
+	ret = radix_tree_insert(&fs_info->buffer_radix,
+				start >> PAGE_CACHE_SHIFT, eb);
+	spin_unlock(&fs_info->buffer_lock);
+	radix_tree_preload_end();
+	if (ret == -EEXIST) {
+		exists = find_extent_buffer(fs_info, start);
+		if (exists)
+			goto free_eb;
+		else
+			goto again;
+	}
+	check_buffer_tree_ref(eb);
+	set_bit(EXTENT_BUFFER_IN_TREE, &eb->bflags);
+
+	/*
+	 * We will free dummy extent buffer's if they come into
+	 * free_extent_buffer with a ref count of 2, but if we are using this we
+	 * want the buffers to stay in memory until we're done with them, so
+	 * bump the ref count again.
+	 */
+	atomic_inc(&eb->refs);
+	return eb;
+free_eb:
+	btrfs_release_extent_buffer(eb);
+	return exists;
+}
+#endif
+
+struct extent_buffer *alloc_extent_buffer(struct btrfs_fs_info *fs_info,
 					  u64 start, unsigned long len)
 {
 	unsigned long num_pages = num_extent_pages(start, len);
@@ -4503,16 +4660,15 @@ struct extent_buffer *alloc_extent_buffer(struct extent_io_tree *tree,
 	struct extent_buffer *eb;
 	struct extent_buffer *exists = NULL;
 	struct page *p;
-	struct address_space *mapping = tree->mapping;
+	struct address_space *mapping = fs_info->btree_inode->i_mapping;
 	int uptodate = 1;
 	int ret;
 
-
-	eb = find_extent_buffer(tree, start);
+	eb = find_extent_buffer(fs_info, start);
 	if (eb)
 		return eb;
 
-	eb = __alloc_extent_buffer(tree, start, len, GFP_NOFS);
+	eb = __alloc_extent_buffer(fs_info, start, len, GFP_NOFS);
 	if (!eb)
 		return NULL;
 
@@ -4535,7 +4691,7 @@ struct extent_buffer *alloc_extent_buffer(struct extent_io_tree *tree,
 				spin_unlock(&mapping->private_lock);
 				unlock_page(p);
 				page_cache_release(p);
-				mark_extent_buffer_accessed(exists);
+				mark_extent_buffer_accessed(exists, p);
 				goto free_eb;
 			}
 
@@ -4550,7 +4706,6 @@ struct extent_buffer *alloc_extent_buffer(struct extent_io_tree *tree,
 		attach_extent_buffer_page(eb, p);
 		spin_unlock(&mapping->private_lock);
 		WARN_ON(PageDirty(p));
-		mark_page_accessed(p);
 		eb->pages[i] = p;
 		if (!PageUptodate(p))
 			uptodate = 0;
@@ -4567,12 +4722,13 @@ again:
 	if (ret)
 		goto free_eb;
 
-	spin_lock(&tree->buffer_lock);
-	ret = radix_tree_insert(&tree->buffer, start >> PAGE_CACHE_SHIFT, eb);
-	spin_unlock(&tree->buffer_lock);
+	spin_lock(&fs_info->buffer_lock);
+	ret = radix_tree_insert(&fs_info->buffer_radix,
+				start >> PAGE_CACHE_SHIFT, eb);
+	spin_unlock(&fs_info->buffer_lock);
 	radix_tree_preload_end();
 	if (ret == -EEXIST) {
-		exists = find_extent_buffer(tree, start);
+		exists = find_extent_buffer(fs_info, start);
 		if (exists)
 			goto free_eb;
 		else
@@ -4580,6 +4736,7 @@ again:
 	}
 	/* add one reference for the tree */
 	check_buffer_tree_ref(eb);
+	set_bit(EXTENT_BUFFER_IN_TREE, &eb->bflags);
 
 	/*
 	 * there is a race where release page may have
@@ -4623,17 +4780,17 @@ static int release_extent_buffer(struct extent_buffer *eb)
 {
 	WARN_ON(atomic_read(&eb->refs) == 0);
 	if (atomic_dec_and_test(&eb->refs)) {
-		if (test_bit(EXTENT_BUFFER_DUMMY, &eb->bflags)) {
-			spin_unlock(&eb->refs_lock);
-		} else {
-			struct extent_io_tree *tree = eb->tree;
+		if (test_and_clear_bit(EXTENT_BUFFER_IN_TREE, &eb->bflags)) {
+			struct btrfs_fs_info *fs_info = eb->fs_info;
 
 			spin_unlock(&eb->refs_lock);
 
-			spin_lock(&tree->buffer_lock);
-			radix_tree_delete(&tree->buffer,
+			spin_lock(&fs_info->buffer_lock);
+			radix_tree_delete(&fs_info->buffer_radix,
 					  eb->start >> PAGE_CACHE_SHIFT);
-			spin_unlock(&tree->buffer_lock);
+			spin_unlock(&fs_info->buffer_lock);
+		} else {
+			spin_unlock(&eb->refs_lock);
 		}
 
 		/* Should be safe to release our pages at this point */
@@ -4906,6 +5063,43 @@ void read_extent_buffer(struct extent_buffer *eb, void *dstv,
 	}
 }
 
+int read_extent_buffer_to_user(struct extent_buffer *eb, void __user *dstv,
+			unsigned long start,
+			unsigned long len)
+{
+	size_t cur;
+	size_t offset;
+	struct page *page;
+	char *kaddr;
+	char __user *dst = (char __user *)dstv;
+	size_t start_offset = eb->start & ((u64)PAGE_CACHE_SIZE - 1);
+	unsigned long i = (start_offset + start) >> PAGE_CACHE_SHIFT;
+	int ret = 0;
+
+	WARN_ON(start > eb->len);
+	WARN_ON(start + len > eb->start + eb->len);
+
+	offset = (start_offset + start) & (PAGE_CACHE_SIZE - 1);
+
+	while (len > 0) {
+		page = extent_buffer_page(eb, i);
+
+		cur = min(len, (PAGE_CACHE_SIZE - offset));
+		kaddr = page_address(page);
+		if (copy_to_user(dst, kaddr + offset, cur)) {
+			ret = -EFAULT;
+			break;
+		}
+
+		dst += cur;
+		len -= cur;
+		offset = 0;
+		i++;
+	}
+
+	return ret;
+}
+
 int map_private_extent_buffer(struct extent_buffer *eb, unsigned long start,
 			       unsigned long min_len, char **map,
 			       unsigned long *map_start,
@@ -5112,12 +5306,12 @@ void memcpy_extent_buffer(struct extent_buffer *dst, unsigned long dst_offset,
 	unsigned long src_i;
 
 	if (src_offset + len > dst->len) {
-		printk(KERN_ERR "btrfs memmove bogus src_offset %lu move "
+		printk(KERN_ERR "BTRFS: memmove bogus src_offset %lu move "
 		       "len %lu dst len %lu\n", src_offset, len, dst->len);
 		BUG_ON(1);
 	}
 	if (dst_offset + len > dst->len) {
-		printk(KERN_ERR "btrfs memmove bogus dst_offset %lu move "
+		printk(KERN_ERR "BTRFS: memmove bogus dst_offset %lu move "
 		       "len %lu dst len %lu\n", dst_offset, len, dst->len);
 		BUG_ON(1);
 	}
@@ -5159,12 +5353,12 @@ void memmove_extent_buffer(struct extent_buffer *dst, unsigned long dst_offset,
 	unsigned long src_i;
 
 	if (src_offset + len > dst->len) {
-		printk(KERN_ERR "btrfs memmove bogus src_offset %lu move "
+		printk(KERN_ERR "BTRFS: memmove bogus src_offset %lu move "
 		       "len %lu len %lu\n", src_offset, len, dst->len);
 		BUG_ON(1);
 	}
 	if (dst_offset + len > dst->len) {
-		printk(KERN_ERR "btrfs memmove bogus dst_offset %lu move "
+		printk(KERN_ERR "BTRFS: memmove bogus dst_offset %lu move "
 		       "len %lu len %lu\n", dst_offset, len, dst->len);
 		BUG_ON(1);
 	}