1 files changed, 748 insertions, 0 deletions

diff --git a/fs/btrfs/inode-item.c b/fs/btrfs/inode-item.c
new file mode 100644
index 000000000..5add022d3
--- /dev/null
+++ b/fs/btrfs/inode-item.c
@@ -0,0 +1,748 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2007 Oracle.  All rights reserved.
+ */
+
+#include "ctree.h"
+#include "inode-item.h"
+#include "disk-io.h"
+#include "transaction.h"
+#include "print-tree.h"
+
+struct btrfs_inode_ref *btrfs_find_name_in_backref(struct extent_buffer *leaf,
+						   int slot,
+						   const struct fscrypt_str *name)
+{
+	struct btrfs_inode_ref *ref;
+	unsigned long ptr;
+	unsigned long name_ptr;
+	u32 item_size;
+	u32 cur_offset = 0;
+	int len;
+
+	item_size = btrfs_item_size(leaf, slot);
+	ptr = btrfs_item_ptr_offset(leaf, slot);
+	while (cur_offset < item_size) {
+		ref = (struct btrfs_inode_ref *)(ptr + cur_offset);
+		len = btrfs_inode_ref_name_len(leaf, ref);
+		name_ptr = (unsigned long)(ref + 1);
+		cur_offset += len + sizeof(*ref);
+		if (len != name->len)
+			continue;
+		if (memcmp_extent_buffer(leaf, name->name, name_ptr,
+					 name->len) == 0)
+			return ref;
+	}
+	return NULL;
+}
+
+struct btrfs_inode_extref *btrfs_find_name_in_ext_backref(
+		struct extent_buffer *leaf, int slot, u64 ref_objectid,
+		const struct fscrypt_str *name)
+{
+	struct btrfs_inode_extref *extref;
+	unsigned long ptr;
+	unsigned long name_ptr;
+	u32 item_size;
+	u32 cur_offset = 0;
+	int ref_name_len;
+
+	item_size = btrfs_item_size(leaf, slot);
+	ptr = btrfs_item_ptr_offset(leaf, slot);
+
+	/*
+	 * Search all extended backrefs in this item. We're only
+	 * looking through any collisions so most of the time this is
+	 * just going to compare against one buffer. If all is well,
+	 * we'll return success and the inode ref object.
+	 */
+	while (cur_offset < item_size) {
+		extref = (struct btrfs_inode_extref *) (ptr + cur_offset);
+		name_ptr = (unsigned long)(&extref->name);
+		ref_name_len = btrfs_inode_extref_name_len(leaf, extref);
+
+		if (ref_name_len == name->len &&
+		    btrfs_inode_extref_parent(leaf, extref) == ref_objectid &&
+		    (memcmp_extent_buffer(leaf, name->name, name_ptr,
+					  name->len) == 0))
+			return extref;
+
+		cur_offset += ref_name_len + sizeof(*extref);
+	}
+	return NULL;
+}
+
+/* Returns NULL if no extref found */
+struct btrfs_inode_extref *
+btrfs_lookup_inode_extref(struct btrfs_trans_handle *trans,
+			  struct btrfs_root *root,
+			  struct btrfs_path *path,
+			  const struct fscrypt_str *name,
+			  u64 inode_objectid, u64 ref_objectid, int ins_len,
+			  int cow)
+{
+	int ret;
+	struct btrfs_key key;
+
+	key.objectid = inode_objectid;
+	key.type = BTRFS_INODE_EXTREF_KEY;
+	key.offset = btrfs_extref_hash(ref_objectid, name->name, name->len);
+
+	ret = btrfs_search_slot(trans, root, &key, path, ins_len, cow);
+	if (ret < 0)
+		return ERR_PTR(ret);
+	if (ret > 0)
+		return NULL;
+	return btrfs_find_name_in_ext_backref(path->nodes[0], path->slots[0],
+					      ref_objectid, name);
+
+}
+
+static int btrfs_del_inode_extref(struct btrfs_trans_handle *trans,
+				  struct btrfs_root *root,
+				  const struct fscrypt_str *name,
+				  u64 inode_objectid, u64 ref_objectid,
+				  u64 *index)
+{
+	struct btrfs_path *path;
+	struct btrfs_key key;
+	struct btrfs_inode_extref *extref;
+	struct extent_buffer *leaf;
+	int ret;
+	int del_len = name->len + sizeof(*extref);
+	unsigned long ptr;
+	unsigned long item_start;
+	u32 item_size;
+
+	key.objectid = inode_objectid;
+	key.type = BTRFS_INODE_EXTREF_KEY;
+	key.offset = btrfs_extref_hash(ref_objectid, name->name, name->len);
+
+	path = btrfs_alloc_path();
+	if (!path)
+		return -ENOMEM;
+
+	ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
+	if (ret > 0)
+		ret = -ENOENT;
+	if (ret < 0)
+		goto out;
+
+	/*
+	 * Sanity check - did we find the right item for this name?
+	 * This should always succeed so error here will make the FS
+	 * readonly.
+	 */
+	extref = btrfs_find_name_in_ext_backref(path->nodes[0], path->slots[0],
+						ref_objectid, name);
+	if (!extref) {
+		btrfs_handle_fs_error(root->fs_info, -ENOENT, NULL);
+		ret = -EROFS;
+		goto out;
+	}
+
+	leaf = path->nodes[0];
+	item_size = btrfs_item_size(leaf, path->slots[0]);
+	if (index)
+		*index = btrfs_inode_extref_index(leaf, extref);
+
+	if (del_len == item_size) {
+		/*
+		 * Common case only one ref in the item, remove the
+		 * whole item.
+		 */
+		ret = btrfs_del_item(trans, root, path);
+		goto out;
+	}
+
+	ptr = (unsigned long)extref;
+	item_start = btrfs_item_ptr_offset(leaf, path->slots[0]);
+
+	memmove_extent_buffer(leaf, ptr, ptr + del_len,
+			      item_size - (ptr + del_len - item_start));
+
+	btrfs_truncate_item(path, item_size - del_len, 1);
+
+out:
+	btrfs_free_path(path);
+
+	return ret;
+}
+
+int btrfs_del_inode_ref(struct btrfs_trans_handle *trans,
+			struct btrfs_root *root, const struct fscrypt_str *name,
+			u64 inode_objectid, u64 ref_objectid, u64 *index)
+{
+	struct btrfs_path *path;
+	struct btrfs_key key;
+	struct btrfs_inode_ref *ref;
+	struct extent_buffer *leaf;
+	unsigned long ptr;
+	unsigned long item_start;
+	u32 item_size;
+	u32 sub_item_len;
+	int ret;
+	int search_ext_refs = 0;
+	int del_len = name->len + sizeof(*ref);
+
+	key.objectid = inode_objectid;
+	key.offset = ref_objectid;
+	key.type = BTRFS_INODE_REF_KEY;
+
+	path = btrfs_alloc_path();
+	if (!path)
+		return -ENOMEM;
+
+	ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
+	if (ret > 0) {
+		ret = -ENOENT;
+		search_ext_refs = 1;
+		goto out;
+	} else if (ret < 0) {
+		goto out;
+	}
+
+	ref = btrfs_find_name_in_backref(path->nodes[0], path->slots[0], name);
+	if (!ref) {
+		ret = -ENOENT;
+		search_ext_refs = 1;
+		goto out;
+	}
+	leaf = path->nodes[0];
+	item_size = btrfs_item_size(leaf, path->slots[0]);
+
+	if (index)
+		*index = btrfs_inode_ref_index(leaf, ref);
+
+	if (del_len == item_size) {
+		ret = btrfs_del_item(trans, root, path);
+		goto out;
+	}
+	ptr = (unsigned long)ref;
+	sub_item_len = name->len + sizeof(*ref);
+	item_start = btrfs_item_ptr_offset(leaf, path->slots[0]);
+	memmove_extent_buffer(leaf, ptr, ptr + sub_item_len,
+			      item_size - (ptr + sub_item_len - item_start));
+	btrfs_truncate_item(path, item_size - sub_item_len, 1);
+out:
+	btrfs_free_path(path);
+
+	if (search_ext_refs) {
+		/*
+		 * No refs were found, or we could not find the
+		 * name in our ref array. Find and remove the extended
+		 * inode ref then.
+		 */
+		return btrfs_del_inode_extref(trans, root, name,
+					      inode_objectid, ref_objectid, index);
+	}
+
+	return ret;
+}
+
+/*
+ * btrfs_insert_inode_extref() - Inserts an extended inode ref into a tree.
+ *
+ * The caller must have checked against BTRFS_LINK_MAX already.
+ */
+static int btrfs_insert_inode_extref(struct btrfs_trans_handle *trans,
+				     struct btrfs_root *root,
+				     const struct fscrypt_str *name,
+				     u64 inode_objectid, u64 ref_objectid,
+				     u64 index)
+{
+	struct btrfs_inode_extref *extref;
+	int ret;
+	int ins_len = name->len + sizeof(*extref);
+	unsigned long ptr;
+	struct btrfs_path *path;
+	struct btrfs_key key;
+	struct extent_buffer *leaf;
+
+	key.objectid = inode_objectid;
+	key.type = BTRFS_INODE_EXTREF_KEY;
+	key.offset = btrfs_extref_hash(ref_objectid, name->name, name->len);
+
+	path = btrfs_alloc_path();
+	if (!path)
+		return -ENOMEM;
+
+	ret = btrfs_insert_empty_item(trans, root, path, &key,
+				      ins_len);
+	if (ret == -EEXIST) {
+		if (btrfs_find_name_in_ext_backref(path->nodes[0],
+						   path->slots[0],
+						   ref_objectid,
+						   name))
+			goto out;
+
+		btrfs_extend_item(path, ins_len);
+		ret = 0;
+	}
+	if (ret < 0)
+		goto out;
+
+	leaf = path->nodes[0];
+	ptr = (unsigned long)btrfs_item_ptr(leaf, path->slots[0], char);
+	ptr += btrfs_item_size(leaf, path->slots[0]) - ins_len;
+	extref = (struct btrfs_inode_extref *)ptr;
+
+	btrfs_set_inode_extref_name_len(path->nodes[0], extref, name->len);
+	btrfs_set_inode_extref_index(path->nodes[0], extref, index);
+	btrfs_set_inode_extref_parent(path->nodes[0], extref, ref_objectid);
+
+	ptr = (unsigned long)&extref->name;
+	write_extent_buffer(path->nodes[0], name->name, ptr, name->len);
+	btrfs_mark_buffer_dirty(path->nodes[0]);
+
+out:
+	btrfs_free_path(path);
+	return ret;
+}
+
+/* Will return 0, -ENOMEM, -EMLINK, or -EEXIST or anything from the CoW path */
+int btrfs_insert_inode_ref(struct btrfs_trans_handle *trans,
+			   struct btrfs_root *root, const struct fscrypt_str *name,
+			   u64 inode_objectid, u64 ref_objectid, u64 index)
+{
+	struct btrfs_fs_info *fs_info = root->fs_info;
+	struct btrfs_path *path;
+	struct btrfs_key key;
+	struct btrfs_inode_ref *ref;
+	unsigned long ptr;
+	int ret;
+	int ins_len = name->len + sizeof(*ref);
+
+	key.objectid = inode_objectid;
+	key.offset = ref_objectid;
+	key.type = BTRFS_INODE_REF_KEY;
+
+	path = btrfs_alloc_path();
+	if (!path)
+		return -ENOMEM;
+
+	path->skip_release_on_error = 1;
+	ret = btrfs_insert_empty_item(trans, root, path, &key,
+				      ins_len);
+	if (ret == -EEXIST) {
+		u32 old_size;
+		ref = btrfs_find_name_in_backref(path->nodes[0], path->slots[0],
+						 name);
+		if (ref)
+			goto out;
+
+		old_size = btrfs_item_size(path->nodes[0], path->slots[0]);
+		btrfs_extend_item(path, ins_len);
+		ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
+				     struct btrfs_inode_ref);
+		ref = (struct btrfs_inode_ref *)((unsigned long)ref + old_size);
+		btrfs_set_inode_ref_name_len(path->nodes[0], ref, name->len);
+		btrfs_set_inode_ref_index(path->nodes[0], ref, index);
+		ptr = (unsigned long)(ref + 1);
+		ret = 0;
+	} else if (ret < 0) {
+		if (ret == -EOVERFLOW) {
+			if (btrfs_find_name_in_backref(path->nodes[0],
+						       path->slots[0],
+						       name))
+				ret = -EEXIST;
+			else
+				ret = -EMLINK;
+		}
+		goto out;
+	} else {
+		ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
+				     struct btrfs_inode_ref);
+		btrfs_set_inode_ref_name_len(path->nodes[0], ref, name->len);
+		btrfs_set_inode_ref_index(path->nodes[0], ref, index);
+		ptr = (unsigned long)(ref + 1);
+	}
+	write_extent_buffer(path->nodes[0], name->name, ptr, name->len);
+	btrfs_mark_buffer_dirty(path->nodes[0]);
+
+out:
+	btrfs_free_path(path);
+
+	if (ret == -EMLINK) {
+		struct btrfs_super_block *disk_super = fs_info->super_copy;
+		/* We ran out of space in the ref array. Need to
+		 * add an extended ref. */
+		if (btrfs_super_incompat_flags(disk_super)
+		    & BTRFS_FEATURE_INCOMPAT_EXTENDED_IREF)
+			ret = btrfs_insert_inode_extref(trans, root, name,
+							inode_objectid,
+							ref_objectid, index);
+	}
+
+	return ret;
+}
+
+int btrfs_insert_empty_inode(struct btrfs_trans_handle *trans,
+			     struct btrfs_root *root,
+			     struct btrfs_path *path, u64 objectid)
+{
+	struct btrfs_key key;
+	int ret;
+	key.objectid = objectid;
+	key.type = BTRFS_INODE_ITEM_KEY;
+	key.offset = 0;
+
+	ret = btrfs_insert_empty_item(trans, root, path, &key,
+				      sizeof(struct btrfs_inode_item));
+	return ret;
+}
+
+int btrfs_lookup_inode(struct btrfs_trans_handle *trans, struct btrfs_root
+		       *root, struct btrfs_path *path,
+		       struct btrfs_key *location, int mod)
+{
+	int ins_len = mod < 0 ? -1 : 0;
+	int cow = mod != 0;
+	int ret;
+	int slot;
+	struct extent_buffer *leaf;
+	struct btrfs_key found_key;
+
+	ret = btrfs_search_slot(trans, root, location, path, ins_len, cow);
+	if (ret > 0 && location->type == BTRFS_ROOT_ITEM_KEY &&
+	    location->offset == (u64)-1 && path->slots[0] != 0) {
+		slot = path->slots[0] - 1;
+		leaf = path->nodes[0];
+		btrfs_item_key_to_cpu(leaf, &found_key, slot);
+		if (found_key.objectid == location->objectid &&
+		    found_key.type == location->type) {
+			path->slots[0]--;
+			return 0;
+		}
+	}
+	return ret;
+}
+
+static inline void btrfs_trace_truncate(struct btrfs_inode *inode,
+					struct extent_buffer *leaf,
+					struct btrfs_file_extent_item *fi,
+					u64 offset, int extent_type, int slot)
+{
+	if (!inode)
+		return;
+	if (extent_type == BTRFS_FILE_EXTENT_INLINE)
+		trace_btrfs_truncate_show_fi_inline(inode, leaf, fi, slot,
+						    offset);
+	else
+		trace_btrfs_truncate_show_fi_regular(inode, leaf, fi, offset);
+}
+
+/*
+ * Remove inode items from a given root.
+ *
+ * @trans:		A transaction handle.
+ * @root:		The root from which to remove items.
+ * @inode:		The inode whose items we want to remove.
+ * @control:		The btrfs_truncate_control to control how and what we
+ *			are truncating.
+ *
+ * Remove all keys associated with the inode from the given root that have a key
+ * with a type greater than or equals to @min_type. When @min_type has a value of
+ * BTRFS_EXTENT_DATA_KEY, only remove file extent items that have an offset value
+ * greater than or equals to @new_size. If a file extent item that starts before
+ * @new_size and ends after it is found, its length is adjusted.
+ *
+ * Returns: 0 on success, < 0 on error and NEED_TRUNCATE_BLOCK when @min_type is
+ * BTRFS_EXTENT_DATA_KEY and the caller must truncate the last block.
+ */
+int btrfs_truncate_inode_items(struct btrfs_trans_handle *trans,
+			       struct btrfs_root *root,
+			       struct btrfs_truncate_control *control)
+{
+	struct btrfs_fs_info *fs_info = root->fs_info;
+	struct btrfs_path *path;
+	struct extent_buffer *leaf;
+	struct btrfs_file_extent_item *fi;
+	struct btrfs_key key;
+	struct btrfs_key found_key;
+	u64 new_size = control->new_size;
+	u64 extent_num_bytes = 0;
+	u64 extent_offset = 0;
+	u64 item_end = 0;
+	u32 found_type = (u8)-1;
+	int del_item;
+	int pending_del_nr = 0;
+	int pending_del_slot = 0;
+	int extent_type = -1;
+	int ret;
+	u64 bytes_deleted = 0;
+	bool be_nice = false;
+
+	ASSERT(control->inode || !control->clear_extent_range);
+	ASSERT(new_size == 0 || control->min_type == BTRFS_EXTENT_DATA_KEY);
+
+	control->last_size = new_size;
+	control->sub_bytes = 0;
+
+	/*
+	 * For shareable roots we want to back off from time to time, this turns
+	 * out to be subvolume roots, reloc roots, and data reloc roots.
+	 */
+	if (test_bit(BTRFS_ROOT_SHAREABLE, &root->state))
+		be_nice = true;
+
+	path = btrfs_alloc_path();
+	if (!path)
+		return -ENOMEM;
+	path->reada = READA_BACK;
+
+	key.objectid = control->ino;
+	key.offset = (u64)-1;
+	key.type = (u8)-1;
+
+search_again:
+	/*
+	 * With a 16K leaf size and 128MiB extents, you can actually queue up a
+	 * huge file in a single leaf.  Most of the time that bytes_deleted is
+	 * > 0, it will be huge by the time we get here
+	 */
+	if (be_nice && bytes_deleted > SZ_32M &&
+	    btrfs_should_end_transaction(trans)) {
+		ret = -EAGAIN;
+		goto out;
+	}
+
+	ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
+	if (ret < 0)
+		goto out;
+
+	if (ret > 0) {
+		ret = 0;
+		/* There are no items in the tree for us to truncate, we're done */
+		if (path->slots[0] == 0)
+			goto out;
+		path->slots[0]--;
+	}
+
+	while (1) {
+		u64 clear_start = 0, clear_len = 0, extent_start = 0;
+		bool should_throttle = false;
+
+		fi = NULL;
+		leaf = path->nodes[0];
+		btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
+		found_type = found_key.type;
+
+		if (found_key.objectid != control->ino)
+			break;
+
+		if (found_type < control->min_type)
+			break;
+
+		item_end = found_key.offset;
+		if (found_type == BTRFS_EXTENT_DATA_KEY) {
+			fi = btrfs_item_ptr(leaf, path->slots[0],
+					    struct btrfs_file_extent_item);
+			extent_type = btrfs_file_extent_type(leaf, fi);
+			if (extent_type != BTRFS_FILE_EXTENT_INLINE)
+				item_end +=
+				    btrfs_file_extent_num_bytes(leaf, fi);
+			else if (extent_type == BTRFS_FILE_EXTENT_INLINE)
+				item_end += btrfs_file_extent_ram_bytes(leaf, fi);
+
+			btrfs_trace_truncate(control->inode, leaf, fi,
+					     found_key.offset, extent_type,
+					     path->slots[0]);
+			item_end--;
+		}
+		if (found_type > control->min_type) {
+			del_item = 1;
+		} else {
+			if (item_end < new_size)
+				break;
+			if (found_key.offset >= new_size)
+				del_item = 1;
+			else
+				del_item = 0;
+		}
+
+		/* FIXME, shrink the extent if the ref count is only 1 */
+		if (found_type != BTRFS_EXTENT_DATA_KEY)
+			goto delete;
+
+		control->extents_found++;
+
+		if (extent_type != BTRFS_FILE_EXTENT_INLINE) {
+			u64 num_dec;
+
+			clear_start = found_key.offset;
+			extent_start = btrfs_file_extent_disk_bytenr(leaf, fi);
+			if (!del_item) {
+				u64 orig_num_bytes =
+					btrfs_file_extent_num_bytes(leaf, fi);
+				extent_num_bytes = ALIGN(new_size -
+						found_key.offset,
+						fs_info->sectorsize);
+				clear_start = ALIGN(new_size, fs_info->sectorsize);
+
+				btrfs_set_file_extent_num_bytes(leaf, fi,
+							 extent_num_bytes);
+				num_dec = (orig_num_bytes - extent_num_bytes);
+				if (extent_start != 0)
+					control->sub_bytes += num_dec;
+				btrfs_mark_buffer_dirty(leaf);
+			} else {
+				extent_num_bytes =
+					btrfs_file_extent_disk_num_bytes(leaf, fi);
+				extent_offset = found_key.offset -
+					btrfs_file_extent_offset(leaf, fi);
+
+				/* FIXME blocksize != 4096 */
+				num_dec = btrfs_file_extent_num_bytes(leaf, fi);
+				if (extent_start != 0)
+					control->sub_bytes += num_dec;
+			}
+			clear_len = num_dec;
+		} else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
+			/*
+			 * We can't truncate inline items that have had
+			 * special encodings
+			 */
+			if (!del_item &&
+			    btrfs_file_extent_encryption(leaf, fi) == 0 &&
+			    btrfs_file_extent_other_encoding(leaf, fi) == 0 &&
+			    btrfs_file_extent_compression(leaf, fi) == 0) {
+				u32 size = (u32)(new_size - found_key.offset);
+
+				btrfs_set_file_extent_ram_bytes(leaf, fi, size);
+				size = btrfs_file_extent_calc_inline_size(size);
+				btrfs_truncate_item(path, size, 1);
+			} else if (!del_item) {
+				/*
+				 * We have to bail so the last_size is set to
+				 * just before this extent.
+				 */
+				ret = BTRFS_NEED_TRUNCATE_BLOCK;
+				break;
+			} else {
+				/*
+				 * Inline extents are special, we just treat
+				 * them as a full sector worth in the file
+				 * extent tree just for simplicity sake.
+				 */
+				clear_len = fs_info->sectorsize;
+			}
+
+			control->sub_bytes += item_end + 1 - new_size;
+		}
+delete:
+		/*
+		 * We only want to clear the file extent range if we're
+		 * modifying the actual inode's mapping, which is just the
+		 * normal truncate path.
+		 */
+		if (control->clear_extent_range) {
+			ret = btrfs_inode_clear_file_extent_range(control->inode,
+						  clear_start, clear_len);
+			if (ret) {
+				btrfs_abort_transaction(trans, ret);
+				break;
+			}
+		}
+
+		if (del_item) {
+			ASSERT(!pending_del_nr ||
+			       ((path->slots[0] + 1) == pending_del_slot));
+
+			control->last_size = found_key.offset;
+			if (!pending_del_nr) {
+				/* No pending yet, add ourselves */
+				pending_del_slot = path->slots[0];
+				pending_del_nr = 1;
+			} else if (pending_del_nr &&
+				   path->slots[0] + 1 == pending_del_slot) {
+				/* Hop on the pending chunk */
+				pending_del_nr++;
+				pending_del_slot = path->slots[0];
+			}
+		} else {
+			control->last_size = new_size;
+			break;
+		}
+
+		if (del_item && extent_start != 0 && !control->skip_ref_updates) {
+			struct btrfs_ref ref = { 0 };
+
+			bytes_deleted += extent_num_bytes;
+
+			btrfs_init_generic_ref(&ref, BTRFS_DROP_DELAYED_REF,
+					extent_start, extent_num_bytes, 0);
+			btrfs_init_data_ref(&ref, btrfs_header_owner(leaf),
+					control->ino, extent_offset,
+					root->root_key.objectid, false);
+			ret = btrfs_free_extent(trans, &ref);
+			if (ret) {
+				btrfs_abort_transaction(trans, ret);
+				break;
+			}
+			if (be_nice) {
+				if (btrfs_should_throttle_delayed_refs(trans))
+					should_throttle = true;
+			}
+		}
+
+		if (found_type == BTRFS_INODE_ITEM_KEY)
+			break;
+
+		if (path->slots[0] == 0 ||
+		    path->slots[0] != pending_del_slot ||
+		    should_throttle) {
+			if (pending_del_nr) {
+				ret = btrfs_del_items(trans, root, path,
+						pending_del_slot,
+						pending_del_nr);
+				if (ret) {
+					btrfs_abort_transaction(trans, ret);
+					break;
+				}
+				pending_del_nr = 0;
+			}
+			btrfs_release_path(path);
+
+			/*
+			 * We can generate a lot of delayed refs, so we need to
+			 * throttle every once and a while and make sure we're
+			 * adding enough space to keep up with the work we are
+			 * generating.  Since we hold a transaction here we
+			 * can't flush, and we don't want to FLUSH_LIMIT because
+			 * we could have generated too many delayed refs to
+			 * actually allocate, so just bail if we're short and
+			 * let the normal reservation dance happen higher up.
+			 */
+			if (should_throttle) {
+				ret = btrfs_delayed_refs_rsv_refill(fs_info,
+							BTRFS_RESERVE_NO_FLUSH);
+				if (ret) {
+					ret = -EAGAIN;
+					break;
+				}
+			}
+			goto search_again;
+		} else {
+			path->slots[0]--;
+		}
+	}
+out:
+	if (ret >= 0 && pending_del_nr) {
+		int err;
+
+		err = btrfs_del_items(trans, root, path, pending_del_slot,
+				      pending_del_nr);
+		if (err) {
+			btrfs_abort_transaction(trans, err);
+			ret = err;
+		}
+	}
+
+	ASSERT(control->last_size >= new_size);
+	if (!ret && control->last_size > new_size)
+		control->last_size = new_size;
+
+	btrfs_free_path(path);
+	return ret;
+}