relocation.c 109.4 KB
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/*
 * Copyright (C) 2009 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/sched.h>
#include <linux/pagemap.h>
#include <linux/writeback.h>
#include <linux/blkdev.h>
#include <linux/rbtree.h>
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#include <linux/slab.h>
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#include "ctree.h"
#include "disk-io.h"
#include "transaction.h"
#include "volumes.h"
#include "locking.h"
#include "btrfs_inode.h"
#include "async-thread.h"
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#include "free-space-cache.h"
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#include "inode-map.h"
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/*
 * backref_node, mapping_node and tree_block start with this
 */
struct tree_entry {
	struct rb_node rb_node;
	u64 bytenr;
};

/*
 * present a tree block in the backref cache
 */
struct backref_node {
	struct rb_node rb_node;
	u64 bytenr;
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	u64 new_bytenr;
	/* objectid of tree block owner, can be not uptodate */
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	u64 owner;
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	/* link to pending, changed or detached list */
	struct list_head list;
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	/* list of upper level blocks reference this block */
	struct list_head upper;
	/* list of child blocks in the cache */
	struct list_head lower;
	/* NULL if this node is not tree root */
	struct btrfs_root *root;
	/* extent buffer got by COW the block */
	struct extent_buffer *eb;
	/* level of tree block */
	unsigned int level:8;
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	/* is the block in non-reference counted tree */
	unsigned int cowonly:1;
	/* 1 if no child node in the cache */
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	unsigned int lowest:1;
	/* is the extent buffer locked */
	unsigned int locked:1;
	/* has the block been processed */
	unsigned int processed:1;
	/* have backrefs of this block been checked */
	unsigned int checked:1;
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	/*
	 * 1 if corresponding block has been cowed but some upper
	 * level block pointers may not point to the new location
	 */
	unsigned int pending:1;
	/*
	 * 1 if the backref node isn't connected to any other
	 * backref node.
	 */
	unsigned int detached:1;
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};

/*
 * present a block pointer in the backref cache
 */
struct backref_edge {
	struct list_head list[2];
	struct backref_node *node[2];
};

#define LOWER	0
#define UPPER	1

struct backref_cache {
	/* red black tree of all backref nodes in the cache */
	struct rb_root rb_root;
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	/* for passing backref nodes to btrfs_reloc_cow_block */
	struct backref_node *path[BTRFS_MAX_LEVEL];
	/*
	 * list of blocks that have been cowed but some block
	 * pointers in upper level blocks may not reflect the
	 * new location
	 */
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	struct list_head pending[BTRFS_MAX_LEVEL];
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	/* list of backref nodes with no child node */
	struct list_head leaves;
	/* list of blocks that have been cowed in current transaction */
	struct list_head changed;
	/* list of detached backref node. */
	struct list_head detached;

	u64 last_trans;

	int nr_nodes;
	int nr_edges;
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};

/*
 * map address of tree root to tree
 */
struct mapping_node {
	struct rb_node rb_node;
	u64 bytenr;
	void *data;
};

struct mapping_tree {
	struct rb_root rb_root;
	spinlock_t lock;
};

/*
 * present a tree block to process
 */
struct tree_block {
	struct rb_node rb_node;
	u64 bytenr;
	struct btrfs_key key;
	unsigned int level:8;
	unsigned int key_ready:1;
};

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#define MAX_EXTENTS 128

struct file_extent_cluster {
	u64 start;
	u64 end;
	u64 boundary[MAX_EXTENTS];
	unsigned int nr;
};

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struct reloc_control {
	/* block group to relocate */
	struct btrfs_block_group_cache *block_group;
	/* extent tree */
	struct btrfs_root *extent_root;
	/* inode for moving data */
	struct inode *data_inode;
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	struct btrfs_block_rsv *block_rsv;

	struct backref_cache backref_cache;

	struct file_extent_cluster cluster;
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	/* tree blocks have been processed */
	struct extent_io_tree processed_blocks;
	/* map start of tree root to corresponding reloc tree */
	struct mapping_tree reloc_root_tree;
	/* list of reloc trees */
	struct list_head reloc_roots;
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	/* size of metadata reservation for merging reloc trees */
	u64 merging_rsv_size;
	/* size of relocated tree nodes */
	u64 nodes_relocated;

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	u64 search_start;
	u64 extents_found;
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	unsigned int stage:8;
	unsigned int create_reloc_tree:1;
	unsigned int merge_reloc_tree:1;
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	unsigned int found_file_extent:1;
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	unsigned int commit_transaction:1;
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};

/* stages of data relocation */
#define MOVE_DATA_EXTENTS	0
#define UPDATE_DATA_PTRS	1

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static void remove_backref_node(struct backref_cache *cache,
				struct backref_node *node);
static void __mark_block_processed(struct reloc_control *rc,
				   struct backref_node *node);
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static void mapping_tree_init(struct mapping_tree *tree)
{
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	tree->rb_root = RB_ROOT;
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	spin_lock_init(&tree->lock);
}

static void backref_cache_init(struct backref_cache *cache)
{
	int i;
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	cache->rb_root = RB_ROOT;
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	for (i = 0; i < BTRFS_MAX_LEVEL; i++)
		INIT_LIST_HEAD(&cache->pending[i]);
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	INIT_LIST_HEAD(&cache->changed);
	INIT_LIST_HEAD(&cache->detached);
	INIT_LIST_HEAD(&cache->leaves);
}

static void backref_cache_cleanup(struct backref_cache *cache)
{
	struct backref_node *node;
	int i;

	while (!list_empty(&cache->detached)) {
		node = list_entry(cache->detached.next,
				  struct backref_node, list);
		remove_backref_node(cache, node);
	}

	while (!list_empty(&cache->leaves)) {
		node = list_entry(cache->leaves.next,
				  struct backref_node, lower);
		remove_backref_node(cache, node);
	}

	cache->last_trans = 0;

	for (i = 0; i < BTRFS_MAX_LEVEL; i++)
		BUG_ON(!list_empty(&cache->pending[i]));
	BUG_ON(!list_empty(&cache->changed));
	BUG_ON(!list_empty(&cache->detached));
	BUG_ON(!RB_EMPTY_ROOT(&cache->rb_root));
	BUG_ON(cache->nr_nodes);
	BUG_ON(cache->nr_edges);
}

static struct backref_node *alloc_backref_node(struct backref_cache *cache)
{
	struct backref_node *node;

	node = kzalloc(sizeof(*node), GFP_NOFS);
	if (node) {
		INIT_LIST_HEAD(&node->list);
		INIT_LIST_HEAD(&node->upper);
		INIT_LIST_HEAD(&node->lower);
		RB_CLEAR_NODE(&node->rb_node);
		cache->nr_nodes++;
	}
	return node;
}

static void free_backref_node(struct backref_cache *cache,
			      struct backref_node *node)
{
	if (node) {
		cache->nr_nodes--;
		kfree(node);
	}
}

static struct backref_edge *alloc_backref_edge(struct backref_cache *cache)
{
	struct backref_edge *edge;

	edge = kzalloc(sizeof(*edge), GFP_NOFS);
	if (edge)
		cache->nr_edges++;
	return edge;
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}

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static void free_backref_edge(struct backref_cache *cache,
			      struct backref_edge *edge)
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{
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	if (edge) {
		cache->nr_edges--;
		kfree(edge);
	}
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}

static struct rb_node *tree_insert(struct rb_root *root, u64 bytenr,
				   struct rb_node *node)
{
	struct rb_node **p = &root->rb_node;
	struct rb_node *parent = NULL;
	struct tree_entry *entry;

	while (*p) {
		parent = *p;
		entry = rb_entry(parent, struct tree_entry, rb_node);

		if (bytenr < entry->bytenr)
			p = &(*p)->rb_left;
		else if (bytenr > entry->bytenr)
			p = &(*p)->rb_right;
		else
			return parent;
	}

	rb_link_node(node, parent, p);
	rb_insert_color(node, root);
	return NULL;
}

static struct rb_node *tree_search(struct rb_root *root, u64 bytenr)
{
	struct rb_node *n = root->rb_node;
	struct tree_entry *entry;

	while (n) {
		entry = rb_entry(n, struct tree_entry, rb_node);

		if (bytenr < entry->bytenr)
			n = n->rb_left;
		else if (bytenr > entry->bytenr)
			n = n->rb_right;
		else
			return n;
	}
	return NULL;
}

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static void backref_tree_panic(struct rb_node *rb_node, int errno, u64 bytenr)
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{

	struct btrfs_fs_info *fs_info = NULL;
	struct backref_node *bnode = rb_entry(rb_node, struct backref_node,
					      rb_node);
	if (bnode->root)
		fs_info = bnode->root->fs_info;
	btrfs_panic(fs_info, errno, "Inconsistency in backref cache "
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		    "found at offset %llu\n", bytenr);
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}

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/*
 * walk up backref nodes until reach node presents tree root
 */
static struct backref_node *walk_up_backref(struct backref_node *node,
					    struct backref_edge *edges[],
					    int *index)
{
	struct backref_edge *edge;
	int idx = *index;

	while (!list_empty(&node->upper)) {
		edge = list_entry(node->upper.next,
				  struct backref_edge, list[LOWER]);
		edges[idx++] = edge;
		node = edge->node[UPPER];
	}
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	BUG_ON(node->detached);
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	*index = idx;
	return node;
}

/*
 * walk down backref nodes to find start of next reference path
 */
static struct backref_node *walk_down_backref(struct backref_edge *edges[],
					      int *index)
{
	struct backref_edge *edge;
	struct backref_node *lower;
	int idx = *index;

	while (idx > 0) {
		edge = edges[idx - 1];
		lower = edge->node[LOWER];
		if (list_is_last(&edge->list[LOWER], &lower->upper)) {
			idx--;
			continue;
		}
		edge = list_entry(edge->list[LOWER].next,
				  struct backref_edge, list[LOWER]);
		edges[idx - 1] = edge;
		*index = idx;
		return edge->node[UPPER];
	}
	*index = 0;
	return NULL;
}

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static void unlock_node_buffer(struct backref_node *node)
{
	if (node->locked) {
		btrfs_tree_unlock(node->eb);
		node->locked = 0;
	}
}

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static void drop_node_buffer(struct backref_node *node)
{
	if (node->eb) {
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		unlock_node_buffer(node);
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		free_extent_buffer(node->eb);
		node->eb = NULL;
	}
}

static void drop_backref_node(struct backref_cache *tree,
			      struct backref_node *node)
{
	BUG_ON(!list_empty(&node->upper));

	drop_node_buffer(node);
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	list_del(&node->list);
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	list_del(&node->lower);
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	if (!RB_EMPTY_NODE(&node->rb_node))
		rb_erase(&node->rb_node, &tree->rb_root);
	free_backref_node(tree, node);
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}

/*
 * remove a backref node from the backref cache
 */
static void remove_backref_node(struct backref_cache *cache,
				struct backref_node *node)
{
	struct backref_node *upper;
	struct backref_edge *edge;

	if (!node)
		return;

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	BUG_ON(!node->lowest && !node->detached);
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	while (!list_empty(&node->upper)) {
		edge = list_entry(node->upper.next, struct backref_edge,
				  list[LOWER]);
		upper = edge->node[UPPER];
		list_del(&edge->list[LOWER]);
		list_del(&edge->list[UPPER]);
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		free_backref_edge(cache, edge);

		if (RB_EMPTY_NODE(&upper->rb_node)) {
			BUG_ON(!list_empty(&node->upper));
			drop_backref_node(cache, node);
			node = upper;
			node->lowest = 1;
			continue;
		}
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		/*
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		 * add the node to leaf node list if no other
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		 * child block cached.
		 */
		if (list_empty(&upper->lower)) {
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			list_add_tail(&upper->lower, &cache->leaves);
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			upper->lowest = 1;
		}
	}
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	drop_backref_node(cache, node);
}

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static void update_backref_node(struct backref_cache *cache,
				struct backref_node *node, u64 bytenr)
{
	struct rb_node *rb_node;
	rb_erase(&node->rb_node, &cache->rb_root);
	node->bytenr = bytenr;
	rb_node = tree_insert(&cache->rb_root, node->bytenr, &node->rb_node);
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	if (rb_node)
		backref_tree_panic(rb_node, -EEXIST, bytenr);
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}

/*
 * update backref cache after a transaction commit
 */
static int update_backref_cache(struct btrfs_trans_handle *trans,
				struct backref_cache *cache)
{
	struct backref_node *node;
	int level = 0;

	if (cache->last_trans == 0) {
		cache->last_trans = trans->transid;
		return 0;
	}

	if (cache->last_trans == trans->transid)
		return 0;

	/*
	 * detached nodes are used to avoid unnecessary backref
	 * lookup. transaction commit changes the extent tree.
	 * so the detached nodes are no longer useful.
	 */
	while (!list_empty(&cache->detached)) {
		node = list_entry(cache->detached.next,
				  struct backref_node, list);
		remove_backref_node(cache, node);
	}

	while (!list_empty(&cache->changed)) {
		node = list_entry(cache->changed.next,
				  struct backref_node, list);
		list_del_init(&node->list);
		BUG_ON(node->pending);
		update_backref_node(cache, node, node->new_bytenr);
	}

	/*
	 * some nodes can be left in the pending list if there were
	 * errors during processing the pending nodes.
	 */
	for (level = 0; level < BTRFS_MAX_LEVEL; level++) {
		list_for_each_entry(node, &cache->pending[level], list) {
			BUG_ON(!node->pending);
			if (node->bytenr == node->new_bytenr)
				continue;
			update_backref_node(cache, node, node->new_bytenr);
		}
	}

	cache->last_trans = 0;
	return 1;
}

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static int should_ignore_root(struct btrfs_root *root)
{
	struct btrfs_root *reloc_root;

	if (!root->ref_cows)
		return 0;

	reloc_root = root->reloc_root;
	if (!reloc_root)
		return 0;

	if (btrfs_root_last_snapshot(&reloc_root->root_item) ==
	    root->fs_info->running_transaction->transid - 1)
		return 0;
	/*
	 * if there is reloc tree and it was created in previous
	 * transaction backref lookup can find the reloc tree,
	 * so backref node for the fs tree root is useless for
	 * relocation.
	 */
	return 1;
}
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/*
 * find reloc tree by address of tree root
 */
static struct btrfs_root *find_reloc_root(struct reloc_control *rc,
					  u64 bytenr)
{
	struct rb_node *rb_node;
	struct mapping_node *node;
	struct btrfs_root *root = NULL;

	spin_lock(&rc->reloc_root_tree.lock);
	rb_node = tree_search(&rc->reloc_root_tree.rb_root, bytenr);
	if (rb_node) {
		node = rb_entry(rb_node, struct mapping_node, rb_node);
		root = (struct btrfs_root *)node->data;
	}
	spin_unlock(&rc->reloc_root_tree.lock);
	return root;
}

static int is_cowonly_root(u64 root_objectid)
{
	if (root_objectid == BTRFS_ROOT_TREE_OBJECTID ||
	    root_objectid == BTRFS_EXTENT_TREE_OBJECTID ||
	    root_objectid == BTRFS_CHUNK_TREE_OBJECTID ||
	    root_objectid == BTRFS_DEV_TREE_OBJECTID ||
	    root_objectid == BTRFS_TREE_LOG_OBJECTID ||
	    root_objectid == BTRFS_CSUM_TREE_OBJECTID)
		return 1;
	return 0;
}

static struct btrfs_root *read_fs_root(struct btrfs_fs_info *fs_info,
					u64 root_objectid)
{
	struct btrfs_key key;

	key.objectid = root_objectid;
	key.type = BTRFS_ROOT_ITEM_KEY;
	if (is_cowonly_root(root_objectid))
		key.offset = 0;
	else
		key.offset = (u64)-1;

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	return btrfs_get_fs_root(fs_info, &key, false);
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}

#ifdef BTRFS_COMPAT_EXTENT_TREE_V0
static noinline_for_stack
struct btrfs_root *find_tree_root(struct reloc_control *rc,
				  struct extent_buffer *leaf,
				  struct btrfs_extent_ref_v0 *ref0)
{
	struct btrfs_root *root;
	u64 root_objectid = btrfs_ref_root_v0(leaf, ref0);
	u64 generation = btrfs_ref_generation_v0(leaf, ref0);

	BUG_ON(root_objectid == BTRFS_TREE_RELOC_OBJECTID);

	root = read_fs_root(rc->extent_root->fs_info, root_objectid);
	BUG_ON(IS_ERR(root));

	if (root->ref_cows &&
	    generation != btrfs_root_generation(&root->root_item))
		return NULL;

	return root;
}
#endif

static noinline_for_stack
int find_inline_backref(struct extent_buffer *leaf, int slot,
			unsigned long *ptr, unsigned long *end)
{
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	struct btrfs_key key;
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	struct btrfs_extent_item *ei;
	struct btrfs_tree_block_info *bi;
	u32 item_size;

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	btrfs_item_key_to_cpu(leaf, &key, slot);

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	item_size = btrfs_item_size_nr(leaf, slot);
#ifdef BTRFS_COMPAT_EXTENT_TREE_V0
	if (item_size < sizeof(*ei)) {
		WARN_ON(item_size != sizeof(struct btrfs_extent_item_v0));
		return 1;
	}
#endif
	ei = btrfs_item_ptr(leaf, slot, struct btrfs_extent_item);
	WARN_ON(!(btrfs_extent_flags(leaf, ei) &
		  BTRFS_EXTENT_FLAG_TREE_BLOCK));

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	if (key.type == BTRFS_EXTENT_ITEM_KEY &&
	    item_size <= sizeof(*ei) + sizeof(*bi)) {
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		WARN_ON(item_size < sizeof(*ei) + sizeof(*bi));
		return 1;
	}
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	if (key.type == BTRFS_METADATA_ITEM_KEY &&
	    item_size <= sizeof(*ei)) {
		WARN_ON(item_size < sizeof(*ei));
		return 1;
	}
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	if (key.type == BTRFS_EXTENT_ITEM_KEY) {
		bi = (struct btrfs_tree_block_info *)(ei + 1);
		*ptr = (unsigned long)(bi + 1);
	} else {
		*ptr = (unsigned long)(ei + 1);
	}
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	*end = (unsigned long)ei + item_size;
	return 0;
}

/*
 * build backref tree for a given tree block. root of the backref tree
 * corresponds the tree block, leaves of the backref tree correspond
 * roots of b-trees that reference the tree block.
 *
 * the basic idea of this function is check backrefs of a given block
 * to find upper level blocks that refernece the block, and then check
 * bakcrefs of these upper level blocks recursively. the recursion stop
 * when tree root is reached or backrefs for the block is cached.
 *
 * NOTE: if we find backrefs for a block are cached, we know backrefs
 * for all upper level blocks that directly/indirectly reference the
 * block are also cached.
 */
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static noinline_for_stack
struct backref_node *build_backref_tree(struct reloc_control *rc,
					struct btrfs_key *node_key,
					int level, u64 bytenr)
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{
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	struct backref_cache *cache = &rc->backref_cache;
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	struct btrfs_path *path1;
	struct btrfs_path *path2;
	struct extent_buffer *eb;
	struct btrfs_root *root;
	struct backref_node *cur;
	struct backref_node *upper;
	struct backref_node *lower;
	struct backref_node *node = NULL;
	struct backref_node *exist = NULL;
	struct backref_edge *edge;
	struct rb_node *rb_node;
	struct btrfs_key key;
	unsigned long end;
	unsigned long ptr;
	LIST_HEAD(list);
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	LIST_HEAD(useless);
	int cowonly;
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	int ret;
	int err = 0;
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	bool need_check = true;
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	path1 = btrfs_alloc_path();
	path2 = btrfs_alloc_path();
	if (!path1 || !path2) {
		err = -ENOMEM;
		goto out;
	}
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Josef Bacik 已提交
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	path1->reada = 1;
	path2->reada = 2;
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	node = alloc_backref_node(cache);
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	if (!node) {
		err = -ENOMEM;
		goto out;
	}

	node->bytenr = bytenr;
	node->level = level;
	node->lowest = 1;
	cur = node;
again:
	end = 0;
	ptr = 0;
	key.objectid = cur->bytenr;
724
	key.type = BTRFS_METADATA_ITEM_KEY;
725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741
	key.offset = (u64)-1;

	path1->search_commit_root = 1;
	path1->skip_locking = 1;
	ret = btrfs_search_slot(NULL, rc->extent_root, &key, path1,
				0, 0);
	if (ret < 0) {
		err = ret;
		goto out;
	}
	BUG_ON(!ret || !path1->slots[0]);

	path1->slots[0]--;

	WARN_ON(cur->checked);
	if (!list_empty(&cur->upper)) {
		/*
742
		 * the backref was added previously when processing
743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781
		 * backref of type BTRFS_TREE_BLOCK_REF_KEY
		 */
		BUG_ON(!list_is_singular(&cur->upper));
		edge = list_entry(cur->upper.next, struct backref_edge,
				  list[LOWER]);
		BUG_ON(!list_empty(&edge->list[UPPER]));
		exist = edge->node[UPPER];
		/*
		 * add the upper level block to pending list if we need
		 * check its backrefs
		 */
		if (!exist->checked)
			list_add_tail(&edge->list[UPPER], &list);
	} else {
		exist = NULL;
	}

	while (1) {
		cond_resched();
		eb = path1->nodes[0];

		if (ptr >= end) {
			if (path1->slots[0] >= btrfs_header_nritems(eb)) {
				ret = btrfs_next_leaf(rc->extent_root, path1);
				if (ret < 0) {
					err = ret;
					goto out;
				}
				if (ret > 0)
					break;
				eb = path1->nodes[0];
			}

			btrfs_item_key_to_cpu(eb, &key, path1->slots[0]);
			if (key.objectid != cur->bytenr) {
				WARN_ON(exist);
				break;
			}

782 783
			if (key.type == BTRFS_EXTENT_ITEM_KEY ||
			    key.type == BTRFS_METADATA_ITEM_KEY) {
784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812
				ret = find_inline_backref(eb, path1->slots[0],
							  &ptr, &end);
				if (ret)
					goto next;
			}
		}

		if (ptr < end) {
			/* update key for inline back ref */
			struct btrfs_extent_inline_ref *iref;
			iref = (struct btrfs_extent_inline_ref *)ptr;
			key.type = btrfs_extent_inline_ref_type(eb, iref);
			key.offset = btrfs_extent_inline_ref_offset(eb, iref);
			WARN_ON(key.type != BTRFS_TREE_BLOCK_REF_KEY &&
				key.type != BTRFS_SHARED_BLOCK_REF_KEY);
		}

		if (exist &&
		    ((key.type == BTRFS_TREE_BLOCK_REF_KEY &&
		      exist->owner == key.offset) ||
		     (key.type == BTRFS_SHARED_BLOCK_REF_KEY &&
		      exist->bytenr == key.offset))) {
			exist = NULL;
			goto next;
		}

#ifdef BTRFS_COMPAT_EXTENT_TREE_V0
		if (key.type == BTRFS_SHARED_BLOCK_REF_KEY ||
		    key.type == BTRFS_EXTENT_REF_V0_KEY) {
813
			if (key.type == BTRFS_EXTENT_REF_V0_KEY) {
814 815 816
				struct btrfs_extent_ref_v0 *ref0;
				ref0 = btrfs_item_ptr(eb, path1->slots[0],
						struct btrfs_extent_ref_v0);
817
				if (key.objectid == key.offset) {
818
					root = find_tree_root(rc, eb, ref0);
819 820 821 822 823 824
					if (root && !should_ignore_root(root))
						cur->root = root;
					else
						list_add(&cur->list, &useless);
					break;
				}
825 826 827
				if (is_cowonly_root(btrfs_ref_root_v0(eb,
								      ref0)))
					cur->cowonly = 1;
828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843
			}
#else
		BUG_ON(key.type == BTRFS_EXTENT_REF_V0_KEY);
		if (key.type == BTRFS_SHARED_BLOCK_REF_KEY) {
#endif
			if (key.objectid == key.offset) {
				/*
				 * only root blocks of reloc trees use
				 * backref of this type.
				 */
				root = find_reloc_root(rc, cur->bytenr);
				BUG_ON(!root);
				cur->root = root;
				break;
			}

844
			edge = alloc_backref_edge(cache);
845 846 847 848 849 850
			if (!edge) {
				err = -ENOMEM;
				goto out;
			}
			rb_node = tree_search(&cache->rb_root, key.offset);
			if (!rb_node) {
851
				upper = alloc_backref_node(cache);
852
				if (!upper) {
853
					free_backref_edge(cache, edge);
854 855 856 857 858 859 860 861 862 863 864 865 866
					err = -ENOMEM;
					goto out;
				}
				upper->bytenr = key.offset;
				upper->level = cur->level + 1;
				/*
				 *  backrefs for the upper level block isn't
				 *  cached, add the block to pending list
				 */
				list_add_tail(&edge->list[UPPER], &list);
			} else {
				upper = rb_entry(rb_node, struct backref_node,
						 rb_node);
867
				BUG_ON(!upper->checked);
868 869
				INIT_LIST_HEAD(&edge->list[UPPER]);
			}
870
			list_add_tail(&edge->list[LOWER], &cur->upper);
871
			edge->node[LOWER] = cur;
872
			edge->node[UPPER] = upper;
873 874 875 876 877 878 879 880 881 882 883 884 885

			goto next;
		} else if (key.type != BTRFS_TREE_BLOCK_REF_KEY) {
			goto next;
		}

		/* key.type == BTRFS_TREE_BLOCK_REF_KEY */
		root = read_fs_root(rc->extent_root->fs_info, key.offset);
		if (IS_ERR(root)) {
			err = PTR_ERR(root);
			goto out;
		}

886 887 888
		if (!root->ref_cows)
			cur->cowonly = 1;

889 890 891 892
		if (btrfs_root_level(&root->root_item) == cur->level) {
			/* tree root */
			BUG_ON(btrfs_root_bytenr(&root->root_item) !=
			       cur->bytenr);
893 894 895 896
			if (should_ignore_root(root))
				list_add(&cur->list, &useless);
			else
				cur->root = root;
897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914
			break;
		}

		level = cur->level + 1;

		/*
		 * searching the tree to find upper level blocks
		 * reference the block.
		 */
		path2->search_commit_root = 1;
		path2->skip_locking = 1;
		path2->lowest_level = level;
		ret = btrfs_search_slot(NULL, root, node_key, path2, 0, 0);
		path2->lowest_level = 0;
		if (ret < 0) {
			err = ret;
			goto out;
		}
915 916
		if (ret > 0 && path2->slots[level] > 0)
			path2->slots[level]--;
917 918 919 920 921 922

		eb = path2->nodes[level];
		WARN_ON(btrfs_node_blockptr(eb, path2->slots[level]) !=
			cur->bytenr);

		lower = cur;
923
		need_check = true;
924 925 926 927
		for (; level < BTRFS_MAX_LEVEL; level++) {
			if (!path2->nodes[level]) {
				BUG_ON(btrfs_root_bytenr(&root->root_item) !=
				       lower->bytenr);
928 929 930 931
				if (should_ignore_root(root))
					list_add(&lower->list, &useless);
				else
					lower->root = root;
932 933 934
				break;
			}

935
			edge = alloc_backref_edge(cache);
936 937 938 939 940 941 942 943
			if (!edge) {
				err = -ENOMEM;
				goto out;
			}

			eb = path2->nodes[level];
			rb_node = tree_search(&cache->rb_root, eb->start);
			if (!rb_node) {
944
				upper = alloc_backref_node(cache);
945
				if (!upper) {
946
					free_backref_edge(cache, edge);
947 948 949 950 951 952
					err = -ENOMEM;
					goto out;
				}
				upper->bytenr = eb->start;
				upper->owner = btrfs_header_owner(eb);
				upper->level = lower->level + 1;
953 954
				if (!root->ref_cows)
					upper->cowonly = 1;
955 956 957 958 959 960 961 962 963 964 965 966

				/*
				 * if we know the block isn't shared
				 * we can void checking its backrefs.
				 */
				if (btrfs_block_can_be_shared(root, eb))
					upper->checked = 0;
				else
					upper->checked = 1;

				/*
				 * add the block to pending list if we
967 968 969
				 * need check its backrefs, we only do this once
				 * while walking up a tree as we will catch
				 * anything else later on.
970
				 */
971 972
				if (!upper->checked && need_check) {
					need_check = false;
973 974 975 976 977 978 979 980 981
					list_add_tail(&edge->list[UPPER],
						      &list);
				} else
					INIT_LIST_HEAD(&edge->list[UPPER]);
			} else {
				upper = rb_entry(rb_node, struct backref_node,
						 rb_node);
				BUG_ON(!upper->checked);
				INIT_LIST_HEAD(&edge->list[UPPER]);
982 983
				if (!upper->owner)
					upper->owner = btrfs_header_owner(eb);
984 985 986
			}
			list_add_tail(&edge->list[LOWER], &lower->upper);
			edge->node[LOWER] = lower;
987
			edge->node[UPPER] = upper;
988 989 990 991 992 993

			if (rb_node)
				break;
			lower = upper;
			upper = NULL;
		}
994
		btrfs_release_path(path2);
995 996 997 998 999 1000 1001 1002 1003 1004 1005 1006
next:
		if (ptr < end) {
			ptr += btrfs_extent_inline_ref_size(key.type);
			if (ptr >= end) {
				WARN_ON(ptr > end);
				ptr = 0;
				end = 0;
			}
		}
		if (ptr >= end)
			path1->slots[0]++;
	}
1007
	btrfs_release_path(path1);
1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024

	cur->checked = 1;
	WARN_ON(exist);

	/* the pending list isn't empty, take the first block to process */
	if (!list_empty(&list)) {
		edge = list_entry(list.next, struct backref_edge, list[UPPER]);
		list_del_init(&edge->list[UPPER]);
		cur = edge->node[UPPER];
		goto again;
	}

	/*
	 * everything goes well, connect backref nodes and insert backref nodes
	 * into the cache.
	 */
	BUG_ON(!node->checked);
1025 1026 1027 1028
	cowonly = node->cowonly;
	if (!cowonly) {
		rb_node = tree_insert(&cache->rb_root, node->bytenr,
				      &node->rb_node);
1029 1030
		if (rb_node)
			backref_tree_panic(rb_node, -EEXIST, node->bytenr);
1031 1032
		list_add_tail(&node->lower, &cache->leaves);
	}
1033 1034 1035 1036 1037 1038 1039 1040

	list_for_each_entry(edge, &node->upper, list[LOWER])
		list_add_tail(&edge->list[UPPER], &list);

	while (!list_empty(&list)) {
		edge = list_entry(list.next, struct backref_edge, list[UPPER]);
		list_del_init(&edge->list[UPPER]);
		upper = edge->node[UPPER];
1041 1042 1043 1044 1045 1046 1047 1048
		if (upper->detached) {
			list_del(&edge->list[LOWER]);
			lower = edge->node[LOWER];
			free_backref_edge(cache, edge);
			if (list_empty(&lower->upper))
				list_add(&lower->list, &useless);
			continue;
		}
1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060

		if (!RB_EMPTY_NODE(&upper->rb_node)) {
			if (upper->lowest) {
				list_del_init(&upper->lower);
				upper->lowest = 0;
			}

			list_add_tail(&edge->list[UPPER], &upper->lower);
			continue;
		}

		BUG_ON(!upper->checked);
1061 1062 1063 1064
		BUG_ON(cowonly != upper->cowonly);
		if (!cowonly) {
			rb_node = tree_insert(&cache->rb_root, upper->bytenr,
					      &upper->rb_node);
1065 1066 1067
			if (rb_node)
				backref_tree_panic(rb_node, -EEXIST,
						   upper->bytenr);
1068
		}
1069 1070 1071 1072 1073 1074

		list_add_tail(&edge->list[UPPER], &upper->lower);

		list_for_each_entry(edge, &upper->upper, list[LOWER])
			list_add_tail(&edge->list[UPPER], &list);
	}
1075 1076 1077 1078 1079 1080 1081 1082 1083 1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110
	/*
	 * process useless backref nodes. backref nodes for tree leaves
	 * are deleted from the cache. backref nodes for upper level
	 * tree blocks are left in the cache to avoid unnecessary backref
	 * lookup.
	 */
	while (!list_empty(&useless)) {
		upper = list_entry(useless.next, struct backref_node, list);
		list_del_init(&upper->list);
		BUG_ON(!list_empty(&upper->upper));
		if (upper == node)
			node = NULL;
		if (upper->lowest) {
			list_del_init(&upper->lower);
			upper->lowest = 0;
		}
		while (!list_empty(&upper->lower)) {
			edge = list_entry(upper->lower.next,
					  struct backref_edge, list[UPPER]);
			list_del(&edge->list[UPPER]);
			list_del(&edge->list[LOWER]);
			lower = edge->node[LOWER];
			free_backref_edge(cache, edge);

			if (list_empty(&lower->upper))
				list_add(&lower->list, &useless);
		}
		__mark_block_processed(rc, upper);
		if (upper->level > 0) {
			list_add(&upper->list, &cache->detached);
			upper->detached = 1;
		} else {
			rb_erase(&upper->rb_node, &cache->rb_root);
			free_backref_node(cache, upper);
		}
	}
1111 1112 1113 1114
out:
	btrfs_free_path(path1);
	btrfs_free_path(path2);
	if (err) {
1115 1116 1117 1118 1119
		while (!list_empty(&useless)) {
			lower = list_entry(useless.next,
					   struct backref_node, upper);
			list_del_init(&lower->upper);
		}
1120
		upper = node;
1121
		INIT_LIST_HEAD(&list);
1122 1123 1124
		while (upper) {
			if (RB_EMPTY_NODE(&upper->rb_node)) {
				list_splice_tail(&upper->upper, &list);
1125
				free_backref_node(cache, upper);
1126 1127 1128 1129 1130 1131 1132
			}

			if (list_empty(&list))
				break;

			edge = list_entry(list.next, struct backref_edge,
					  list[LOWER]);
1133
			list_del(&edge->list[LOWER]);
1134
			upper = edge->node[UPPER];
1135
			free_backref_edge(cache, edge);
1136 1137 1138
		}
		return ERR_PTR(err);
	}
1139
	BUG_ON(node && node->detached);
1140 1141 1142
	return node;
}

1143 1144 1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155 1156 1157 1158 1159 1160 1161 1162 1163 1164 1165 1166 1167 1168 1169 1170 1171 1172 1173 1174 1175 1176 1177 1178 1179 1180 1181 1182 1183 1184 1185 1186 1187 1188 1189 1190 1191 1192
/*
 * helper to add backref node for the newly created snapshot.
 * the backref node is created by cloning backref node that
 * corresponds to root of source tree
 */
static int clone_backref_node(struct btrfs_trans_handle *trans,
			      struct reloc_control *rc,
			      struct btrfs_root *src,
			      struct btrfs_root *dest)
{
	struct btrfs_root *reloc_root = src->reloc_root;
	struct backref_cache *cache = &rc->backref_cache;
	struct backref_node *node = NULL;
	struct backref_node *new_node;
	struct backref_edge *edge;
	struct backref_edge *new_edge;
	struct rb_node *rb_node;

	if (cache->last_trans > 0)
		update_backref_cache(trans, cache);

	rb_node = tree_search(&cache->rb_root, src->commit_root->start);
	if (rb_node) {
		node = rb_entry(rb_node, struct backref_node, rb_node);
		if (node->detached)
			node = NULL;
		else
			BUG_ON(node->new_bytenr != reloc_root->node->start);
	}

	if (!node) {
		rb_node = tree_search(&cache->rb_root,
				      reloc_root->commit_root->start);
		if (rb_node) {
			node = rb_entry(rb_node, struct backref_node,
					rb_node);
			BUG_ON(node->detached);
		}
	}

	if (!node)
		return 0;

	new_node = alloc_backref_node(cache);
	if (!new_node)
		return -ENOMEM;

	new_node->bytenr = dest->node->start;
	new_node->level = node->level;
	new_node->lowest = node->lowest;
Y
Yan, Zheng 已提交
1193
	new_node->checked = 1;
1194 1195 1196 1197 1198 1199 1200 1201 1202 1203 1204 1205 1206
	new_node->root = dest;

	if (!node->lowest) {
		list_for_each_entry(edge, &node->lower, list[UPPER]) {
			new_edge = alloc_backref_edge(cache);
			if (!new_edge)
				goto fail;

			new_edge->node[UPPER] = new_node;
			new_edge->node[LOWER] = edge->node[LOWER];
			list_add_tail(&new_edge->list[UPPER],
				      &new_node->lower);
		}
M
Miao Xie 已提交
1207 1208
	} else {
		list_add_tail(&new_node->lower, &cache->leaves);
1209 1210 1211 1212
	}

	rb_node = tree_insert(&cache->rb_root, new_node->bytenr,
			      &new_node->rb_node);
1213 1214
	if (rb_node)
		backref_tree_panic(rb_node, -EEXIST, new_node->bytenr);
1215 1216 1217 1218 1219 1220 1221 1222 1223 1224 1225 1226 1227 1228 1229 1230 1231 1232 1233

	if (!new_node->lowest) {
		list_for_each_entry(new_edge, &new_node->lower, list[UPPER]) {
			list_add_tail(&new_edge->list[LOWER],
				      &new_edge->node[LOWER]->upper);
		}
	}
	return 0;
fail:
	while (!list_empty(&new_node->lower)) {
		new_edge = list_entry(new_node->lower.next,
				      struct backref_edge, list[UPPER]);
		list_del(&new_edge->list[UPPER]);
		free_backref_edge(cache, new_edge);
	}
	free_backref_node(cache, new_node);
	return -ENOMEM;
}

1234 1235 1236
/*
 * helper to add 'address of tree root -> reloc tree' mapping
 */
1237
static int __must_check __add_reloc_root(struct btrfs_root *root)
1238 1239 1240 1241 1242 1243
{
	struct rb_node *rb_node;
	struct mapping_node *node;
	struct reloc_control *rc = root->fs_info->reloc_ctl;

	node = kmalloc(sizeof(*node), GFP_NOFS);
1244 1245
	if (!node)
		return -ENOMEM;
1246 1247 1248 1249 1250 1251 1252 1253

	node->bytenr = root->node->start;
	node->data = root;

	spin_lock(&rc->reloc_root_tree.lock);
	rb_node = tree_insert(&rc->reloc_root_tree.rb_root,
			      node->bytenr, &node->rb_node);
	spin_unlock(&rc->reloc_root_tree.lock);
1254 1255 1256
	if (rb_node) {
		btrfs_panic(root->fs_info, -EEXIST, "Duplicate root found "
			    "for start=%llu while inserting into relocation "
1257
			    "tree\n", node->bytenr);
1258 1259
		kfree(node);
		return -EEXIST;
1260
	}
1261 1262 1263 1264 1265 1266

	list_add_tail(&root->root_list, &rc->reloc_roots);
	return 0;
}

/*
1267
 * helper to delete the 'address of tree root -> reloc tree'
1268 1269
 * mapping
 */
1270
static void __del_reloc_root(struct btrfs_root *root)
1271 1272 1273 1274 1275 1276 1277
{
	struct rb_node *rb_node;
	struct mapping_node *node = NULL;
	struct reloc_control *rc = root->fs_info->reloc_ctl;

	spin_lock(&rc->reloc_root_tree.lock);
	rb_node = tree_search(&rc->reloc_root_tree.rb_root,
1278
			      root->node->start);
1279 1280 1281 1282 1283 1284
	if (rb_node) {
		node = rb_entry(rb_node, struct mapping_node, rb_node);
		rb_erase(&node->rb_node, &rc->reloc_root_tree.rb_root);
	}
	spin_unlock(&rc->reloc_root_tree.lock);

1285
	if (!node)
1286
		return;
1287 1288
	BUG_ON((struct btrfs_root *)node->data != root);

1289 1290 1291 1292 1293 1294 1295 1296 1297 1298 1299 1300 1301 1302 1303 1304 1305 1306 1307 1308 1309 1310
	spin_lock(&root->fs_info->trans_lock);
	list_del_init(&root->root_list);
	spin_unlock(&root->fs_info->trans_lock);
	kfree(node);
}

/*
 * helper to update the 'address of tree root -> reloc tree'
 * mapping
 */
static int __update_reloc_root(struct btrfs_root *root, u64 new_bytenr)
{
	struct rb_node *rb_node;
	struct mapping_node *node = NULL;
	struct reloc_control *rc = root->fs_info->reloc_ctl;

	spin_lock(&rc->reloc_root_tree.lock);
	rb_node = tree_search(&rc->reloc_root_tree.rb_root,
			      root->node->start);
	if (rb_node) {
		node = rb_entry(rb_node, struct mapping_node, rb_node);
		rb_erase(&node->rb_node, &rc->reloc_root_tree.rb_root);
1311
	}
1312 1313 1314 1315 1316 1317 1318 1319 1320 1321 1322 1323 1324
	spin_unlock(&rc->reloc_root_tree.lock);

	if (!node)
		return 0;
	BUG_ON((struct btrfs_root *)node->data != root);

	spin_lock(&rc->reloc_root_tree.lock);
	node->bytenr = new_bytenr;
	rb_node = tree_insert(&rc->reloc_root_tree.rb_root,
			      node->bytenr, &node->rb_node);
	spin_unlock(&rc->reloc_root_tree.lock);
	if (rb_node)
		backref_tree_panic(rb_node, -EEXIST, node->bytenr);
1325 1326 1327
	return 0;
}

1328 1329
static struct btrfs_root *create_reloc_root(struct btrfs_trans_handle *trans,
					struct btrfs_root *root, u64 objectid)
1330 1331 1332 1333 1334
{
	struct btrfs_root *reloc_root;
	struct extent_buffer *eb;
	struct btrfs_root_item *root_item;
	struct btrfs_key root_key;
M
Miao Xie 已提交
1335
	u64 last_snap = 0;
1336 1337 1338 1339 1340 1341 1342
	int ret;

	root_item = kmalloc(sizeof(*root_item), GFP_NOFS);
	BUG_ON(!root_item);

	root_key.objectid = BTRFS_TREE_RELOC_OBJECTID;
	root_key.type = BTRFS_ROOT_ITEM_KEY;
1343
	root_key.offset = objectid;
1344

1345 1346 1347 1348 1349 1350
	if (root->root_key.objectid == objectid) {
		/* called by btrfs_init_reloc_root */
		ret = btrfs_copy_root(trans, root, root->commit_root, &eb,
				      BTRFS_TREE_RELOC_OBJECTID);
		BUG_ON(ret);

M
Miao Xie 已提交
1351
		last_snap = btrfs_root_last_snapshot(&root->root_item);
1352 1353 1354 1355 1356 1357 1358 1359 1360 1361 1362 1363 1364 1365
		btrfs_set_root_last_snapshot(&root->root_item,
					     trans->transid - 1);
	} else {
		/*
		 * called by btrfs_reloc_post_snapshot_hook.
		 * the source tree is a reloc tree, all tree blocks
		 * modified after it was created have RELOC flag
		 * set in their headers. so it's OK to not update
		 * the 'last_snapshot'.
		 */
		ret = btrfs_copy_root(trans, root, root->node, &eb,
				      BTRFS_TREE_RELOC_OBJECTID);
		BUG_ON(ret);
	}
1366 1367 1368 1369 1370

	memcpy(root_item, &root->root_item, sizeof(*root_item));
	btrfs_set_root_bytenr(root_item, eb->start);
	btrfs_set_root_level(root_item, btrfs_header_level(eb));
	btrfs_set_root_generation(root_item, trans->transid);
1371 1372 1373 1374 1375 1376

	if (root->root_key.objectid == objectid) {
		btrfs_set_root_refs(root_item, 0);
		memset(&root_item->drop_progress, 0,
		       sizeof(struct btrfs_disk_key));
		root_item->drop_level = 0;
M
Miao Xie 已提交
1377 1378 1379 1380 1381 1382
		/*
		 * abuse rtransid, it is safe because it is impossible to
		 * receive data into a relocation tree.
		 */
		btrfs_set_root_rtransid(root_item, last_snap);
		btrfs_set_root_otransid(root_item, trans->transid);
1383
	}
1384 1385 1386 1387 1388 1389 1390 1391 1392

	btrfs_tree_unlock(eb);
	free_extent_buffer(eb);

	ret = btrfs_insert_root(trans, root->fs_info->tree_root,
				&root_key, root_item);
	BUG_ON(ret);
	kfree(root_item);

1393
	reloc_root = btrfs_read_fs_root(root->fs_info->tree_root, &root_key);
1394 1395
	BUG_ON(IS_ERR(reloc_root));
	reloc_root->last_trans = trans->transid;
1396 1397 1398 1399 1400 1401 1402 1403 1404 1405 1406 1407
	return reloc_root;
}

/*
 * create reloc tree for a given fs tree. reloc tree is just a
 * snapshot of the fs tree with special root objectid.
 */
int btrfs_init_reloc_root(struct btrfs_trans_handle *trans,
			  struct btrfs_root *root)
{
	struct btrfs_root *reloc_root;
	struct reloc_control *rc = root->fs_info->reloc_ctl;
1408
	struct btrfs_block_rsv *rsv;
1409
	int clear_rsv = 0;
1410
	int ret;
1411 1412 1413 1414 1415 1416 1417 1418 1419 1420 1421

	if (root->reloc_root) {
		reloc_root = root->reloc_root;
		reloc_root->last_trans = trans->transid;
		return 0;
	}

	if (!rc || !rc->create_reloc_tree ||
	    root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID)
		return 0;

1422 1423
	if (!trans->reloc_reserved) {
		rsv = trans->block_rsv;
1424 1425 1426 1427 1428
		trans->block_rsv = rc->block_rsv;
		clear_rsv = 1;
	}
	reloc_root = create_reloc_root(trans, root, root->root_key.objectid);
	if (clear_rsv)
1429
		trans->block_rsv = rsv;
1430

1431 1432
	ret = __add_reloc_root(reloc_root);
	BUG_ON(ret < 0);
1433 1434 1435 1436 1437 1438 1439 1440 1441 1442 1443 1444 1445 1446 1447
	root->reloc_root = reloc_root;
	return 0;
}

/*
 * update root item of reloc tree
 */
int btrfs_update_reloc_root(struct btrfs_trans_handle *trans,
			    struct btrfs_root *root)
{
	struct btrfs_root *reloc_root;
	struct btrfs_root_item *root_item;
	int ret;

	if (!root->reloc_root)
C
Chris Mason 已提交
1448
		goto out;
1449 1450 1451 1452

	reloc_root = root->reloc_root;
	root_item = &reloc_root->root_item;

1453 1454
	if (root->fs_info->reloc_ctl->merge_reloc_tree &&
	    btrfs_root_refs(root_item) == 0) {
1455
		root->reloc_root = NULL;
1456
		__del_reloc_root(reloc_root);
1457 1458 1459 1460 1461 1462 1463 1464 1465 1466 1467
	}

	if (reloc_root->commit_root != reloc_root->node) {
		btrfs_set_root_node(root_item, reloc_root->node);
		free_extent_buffer(reloc_root->commit_root);
		reloc_root->commit_root = btrfs_root_node(reloc_root);
	}

	ret = btrfs_update_root(trans, root->fs_info->tree_root,
				&reloc_root->root_key, root_item);
	BUG_ON(ret);
C
Chris Mason 已提交
1468 1469

out:
1470 1471 1472 1473 1474 1475 1476 1477 1478 1479 1480 1481 1482 1483 1484 1485 1486 1487 1488 1489 1490 1491
	return 0;
}

/*
 * helper to find first cached inode with inode number >= objectid
 * in a subvolume
 */
static struct inode *find_next_inode(struct btrfs_root *root, u64 objectid)
{
	struct rb_node *node;
	struct rb_node *prev;
	struct btrfs_inode *entry;
	struct inode *inode;

	spin_lock(&root->inode_lock);
again:
	node = root->inode_tree.rb_node;
	prev = NULL;
	while (node) {
		prev = node;
		entry = rb_entry(node, struct btrfs_inode, rb_node);

L
Li Zefan 已提交
1492
		if (objectid < btrfs_ino(&entry->vfs_inode))
1493
			node = node->rb_left;
L
Li Zefan 已提交
1494
		else if (objectid > btrfs_ino(&entry->vfs_inode))
1495 1496 1497 1498 1499 1500 1501
			node = node->rb_right;
		else
			break;
	}
	if (!node) {
		while (prev) {
			entry = rb_entry(prev, struct btrfs_inode, rb_node);
L
Li Zefan 已提交
1502
			if (objectid <= btrfs_ino(&entry->vfs_inode)) {
1503 1504 1505 1506 1507 1508 1509 1510 1511 1512 1513 1514 1515 1516
				node = prev;
				break;
			}
			prev = rb_next(prev);
		}
	}
	while (node) {
		entry = rb_entry(node, struct btrfs_inode, rb_node);
		inode = igrab(&entry->vfs_inode);
		if (inode) {
			spin_unlock(&root->inode_lock);
			return inode;
		}

L
Li Zefan 已提交
1517
		objectid = btrfs_ino(&entry->vfs_inode) + 1;
1518 1519 1520 1521 1522 1523 1524 1525 1526 1527 1528 1529 1530 1531 1532 1533 1534 1535 1536 1537 1538 1539 1540 1541 1542 1543 1544 1545 1546 1547 1548 1549 1550 1551 1552
		if (cond_resched_lock(&root->inode_lock))
			goto again;

		node = rb_next(node);
	}
	spin_unlock(&root->inode_lock);
	return NULL;
}

static int in_block_group(u64 bytenr,
			  struct btrfs_block_group_cache *block_group)
{
	if (bytenr >= block_group->key.objectid &&
	    bytenr < block_group->key.objectid + block_group->key.offset)
		return 1;
	return 0;
}

/*
 * get new location of data
 */
static int get_new_location(struct inode *reloc_inode, u64 *new_bytenr,
			    u64 bytenr, u64 num_bytes)
{
	struct btrfs_root *root = BTRFS_I(reloc_inode)->root;
	struct btrfs_path *path;
	struct btrfs_file_extent_item *fi;
	struct extent_buffer *leaf;
	int ret;

	path = btrfs_alloc_path();
	if (!path)
		return -ENOMEM;

	bytenr -= BTRFS_I(reloc_inode)->index_cnt;
L
Li Zefan 已提交
1553
	ret = btrfs_lookup_file_extent(NULL, root, path, btrfs_ino(reloc_inode),
1554 1555 1556 1557 1558 1559 1560 1561 1562 1563 1564 1565 1566 1567 1568 1569 1570 1571
				       bytenr, 0);
	if (ret < 0)
		goto out;
	if (ret > 0) {
		ret = -ENOENT;
		goto out;
	}

	leaf = path->nodes[0];
	fi = btrfs_item_ptr(leaf, path->slots[0],
			    struct btrfs_file_extent_item);

	BUG_ON(btrfs_file_extent_offset(leaf, fi) ||
	       btrfs_file_extent_compression(leaf, fi) ||
	       btrfs_file_extent_encryption(leaf, fi) ||
	       btrfs_file_extent_other_encoding(leaf, fi));

	if (num_bytes != btrfs_file_extent_disk_num_bytes(leaf, fi)) {
1572
		ret = -EINVAL;
1573 1574 1575
		goto out;
	}

1576
	*new_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1577 1578 1579 1580 1581 1582 1583 1584 1585 1586
	ret = 0;
out:
	btrfs_free_path(path);
	return ret;
}

/*
 * update file extent items in the tree leaf to point to
 * the new locations.
 */
1587 1588 1589 1590 1591
static noinline_for_stack
int replace_file_extents(struct btrfs_trans_handle *trans,
			 struct reloc_control *rc,
			 struct btrfs_root *root,
			 struct extent_buffer *leaf)
1592 1593 1594 1595 1596 1597
{
	struct btrfs_key key;
	struct btrfs_file_extent_item *fi;
	struct inode *inode = NULL;
	u64 parent;
	u64 bytenr;
1598
	u64 new_bytenr = 0;
1599 1600 1601 1602
	u64 num_bytes;
	u64 end;
	u32 nritems;
	u32 i;
1603
	int ret = 0;
1604 1605 1606 1607 1608 1609 1610 1611 1612 1613 1614 1615 1616 1617 1618 1619 1620 1621 1622 1623 1624 1625 1626 1627 1628 1629 1630 1631 1632 1633 1634 1635 1636 1637 1638 1639 1640
	int first = 1;
	int dirty = 0;

	if (rc->stage != UPDATE_DATA_PTRS)
		return 0;

	/* reloc trees always use full backref */
	if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID)
		parent = leaf->start;
	else
		parent = 0;

	nritems = btrfs_header_nritems(leaf);
	for (i = 0; i < nritems; i++) {
		cond_resched();
		btrfs_item_key_to_cpu(leaf, &key, i);
		if (key.type != BTRFS_EXTENT_DATA_KEY)
			continue;
		fi = btrfs_item_ptr(leaf, i, struct btrfs_file_extent_item);
		if (btrfs_file_extent_type(leaf, fi) ==
		    BTRFS_FILE_EXTENT_INLINE)
			continue;
		bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
		num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
		if (bytenr == 0)
			continue;
		if (!in_block_group(bytenr, rc->block_group))
			continue;

		/*
		 * if we are modifying block in fs tree, wait for readpage
		 * to complete and drop the extent cache
		 */
		if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
			if (first) {
				inode = find_next_inode(root, key.objectid);
				first = 0;
L
Li Zefan 已提交
1641
			} else if (inode && btrfs_ino(inode) < key.objectid) {
1642
				btrfs_add_delayed_iput(inode);
1643 1644
				inode = find_next_inode(root, key.objectid);
			}
L
Li Zefan 已提交
1645
			if (inode && btrfs_ino(inode) == key.objectid) {
1646 1647 1648 1649 1650 1651 1652
				end = key.offset +
				      btrfs_file_extent_num_bytes(leaf, fi);
				WARN_ON(!IS_ALIGNED(key.offset,
						    root->sectorsize));
				WARN_ON(!IS_ALIGNED(end, root->sectorsize));
				end--;
				ret = try_lock_extent(&BTRFS_I(inode)->io_tree,
1653
						      key.offset, end);
1654 1655 1656 1657 1658 1659
				if (!ret)
					continue;

				btrfs_drop_extent_cache(inode, key.offset, end,
							1);
				unlock_extent(&BTRFS_I(inode)->io_tree,
1660
					      key.offset, end);
1661 1662 1663 1664 1665
			}
		}

		ret = get_new_location(rc->data_inode, &new_bytenr,
				       bytenr, num_bytes);
1666 1667 1668 1669 1670 1671
		if (ret) {
			/*
			 * Don't have to abort since we've not changed anything
			 * in the file extent yet.
			 */
			break;
1672
		}
1673 1674 1675 1676 1677 1678 1679 1680

		btrfs_set_file_extent_disk_bytenr(leaf, fi, new_bytenr);
		dirty = 1;

		key.offset -= btrfs_file_extent_offset(leaf, fi);
		ret = btrfs_inc_extent_ref(trans, root, new_bytenr,
					   num_bytes, parent,
					   btrfs_header_owner(leaf),
A
Arne Jansen 已提交
1681
					   key.objectid, key.offset, 1);
1682 1683 1684 1685
		if (ret) {
			btrfs_abort_transaction(trans, root, ret);
			break;
		}
1686 1687 1688

		ret = btrfs_free_extent(trans, root, bytenr, num_bytes,
					parent, btrfs_header_owner(leaf),
A
Arne Jansen 已提交
1689
					key.objectid, key.offset, 1);
1690 1691 1692 1693
		if (ret) {
			btrfs_abort_transaction(trans, root, ret);
			break;
		}
1694 1695 1696
	}
	if (dirty)
		btrfs_mark_buffer_dirty(leaf);
1697 1698
	if (inode)
		btrfs_add_delayed_iput(inode);
1699
	return ret;
1700 1701 1702 1703 1704 1705 1706 1707 1708 1709 1710 1711 1712 1713 1714 1715 1716 1717 1718 1719 1720 1721
}

static noinline_for_stack
int memcmp_node_keys(struct extent_buffer *eb, int slot,
		     struct btrfs_path *path, int level)
{
	struct btrfs_disk_key key1;
	struct btrfs_disk_key key2;
	btrfs_node_key(eb, &key1, slot);
	btrfs_node_key(path->nodes[level], &key2, path->slots[level]);
	return memcmp(&key1, &key2, sizeof(key1));
}

/*
 * try to replace tree blocks in fs tree with the new blocks
 * in reloc tree. tree blocks haven't been modified since the
 * reloc tree was create can be replaced.
 *
 * if a block was replaced, level of the block + 1 is returned.
 * if no block got replaced, 0 is returned. if there are other
 * errors, a negative error number is returned.
 */
1722 1723 1724 1725 1726
static noinline_for_stack
int replace_path(struct btrfs_trans_handle *trans,
		 struct btrfs_root *dest, struct btrfs_root *src,
		 struct btrfs_path *path, struct btrfs_key *next_key,
		 int lowest_level, int max_level)
1727 1728 1729 1730 1731 1732 1733 1734 1735 1736
{
	struct extent_buffer *eb;
	struct extent_buffer *parent;
	struct btrfs_key key;
	u64 old_bytenr;
	u64 new_bytenr;
	u64 old_ptr_gen;
	u64 new_ptr_gen;
	u64 last_snapshot;
	u32 blocksize;
1737
	int cow = 0;
1738 1739 1740 1741 1742 1743 1744 1745
	int level;
	int ret;
	int slot;

	BUG_ON(src->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
	BUG_ON(dest->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID);

	last_snapshot = btrfs_root_last_snapshot(&src->root_item);
1746
again:
1747 1748 1749 1750 1751 1752 1753 1754 1755 1756 1757 1758 1759
	slot = path->slots[lowest_level];
	btrfs_node_key_to_cpu(path->nodes[lowest_level], &key, slot);

	eb = btrfs_lock_root_node(dest);
	btrfs_set_lock_blocking(eb);
	level = btrfs_header_level(eb);

	if (level < lowest_level) {
		btrfs_tree_unlock(eb);
		free_extent_buffer(eb);
		return 0;
	}

1760 1761 1762 1763
	if (cow) {
		ret = btrfs_cow_block(trans, dest, eb, NULL, 0, &eb);
		BUG_ON(ret);
	}
1764 1765 1766 1767 1768 1769 1770 1771 1772 1773 1774 1775 1776 1777 1778 1779 1780 1781 1782 1783 1784 1785 1786 1787 1788 1789 1790 1791 1792 1793 1794 1795 1796 1797 1798
	btrfs_set_lock_blocking(eb);

	if (next_key) {
		next_key->objectid = (u64)-1;
		next_key->type = (u8)-1;
		next_key->offset = (u64)-1;
	}

	parent = eb;
	while (1) {
		level = btrfs_header_level(parent);
		BUG_ON(level < lowest_level);

		ret = btrfs_bin_search(parent, &key, level, &slot);
		if (ret && slot > 0)
			slot--;

		if (next_key && slot + 1 < btrfs_header_nritems(parent))
			btrfs_node_key_to_cpu(parent, next_key, slot + 1);

		old_bytenr = btrfs_node_blockptr(parent, slot);
		blocksize = btrfs_level_size(dest, level - 1);
		old_ptr_gen = btrfs_node_ptr_generation(parent, slot);

		if (level <= max_level) {
			eb = path->nodes[level];
			new_bytenr = btrfs_node_blockptr(eb,
							path->slots[level]);
			new_ptr_gen = btrfs_node_ptr_generation(eb,
							path->slots[level]);
		} else {
			new_bytenr = 0;
			new_ptr_gen = 0;
		}

1799
		if (WARN_ON(new_bytenr > 0 && new_bytenr == old_bytenr)) {
1800 1801 1802 1803 1804 1805
			ret = level;
			break;
		}

		if (new_bytenr == 0 || old_ptr_gen > last_snapshot ||
		    memcmp_node_keys(parent, slot, path, level)) {
1806
			if (level <= lowest_level) {
1807 1808 1809 1810 1811 1812
				ret = 0;
				break;
			}

			eb = read_tree_block(dest, old_bytenr, blocksize,
					     old_ptr_gen);
1813 1814 1815
			if (!eb || !extent_buffer_uptodate(eb)) {
				ret = (!eb) ? -ENOMEM : -EIO;
				free_extent_buffer(eb);
1816
				break;
1817
			}
1818
			btrfs_tree_lock(eb);
1819 1820 1821 1822
			if (cow) {
				ret = btrfs_cow_block(trans, dest, eb, parent,
						      slot, &eb);
				BUG_ON(ret);
1823
			}
1824
			btrfs_set_lock_blocking(eb);
1825 1826 1827 1828 1829 1830 1831 1832

			btrfs_tree_unlock(parent);
			free_extent_buffer(parent);

			parent = eb;
			continue;
		}

1833 1834 1835 1836 1837 1838 1839
		if (!cow) {
			btrfs_tree_unlock(parent);
			free_extent_buffer(parent);
			cow = 1;
			goto again;
		}

1840 1841
		btrfs_node_key_to_cpu(path->nodes[level], &key,
				      path->slots[level]);
1842
		btrfs_release_path(path);
1843 1844 1845 1846 1847 1848 1849 1850 1851 1852 1853 1854 1855 1856 1857 1858 1859 1860 1861 1862 1863

		path->lowest_level = level;
		ret = btrfs_search_slot(trans, src, &key, path, 0, 1);
		path->lowest_level = 0;
		BUG_ON(ret);

		/*
		 * swap blocks in fs tree and reloc tree.
		 */
		btrfs_set_node_blockptr(parent, slot, new_bytenr);
		btrfs_set_node_ptr_generation(parent, slot, new_ptr_gen);
		btrfs_mark_buffer_dirty(parent);

		btrfs_set_node_blockptr(path->nodes[level],
					path->slots[level], old_bytenr);
		btrfs_set_node_ptr_generation(path->nodes[level],
					      path->slots[level], old_ptr_gen);
		btrfs_mark_buffer_dirty(path->nodes[level]);

		ret = btrfs_inc_extent_ref(trans, src, old_bytenr, blocksize,
					path->nodes[level]->start,
A
Arne Jansen 已提交
1864 1865
					src->root_key.objectid, level - 1, 0,
					1);
1866 1867 1868
		BUG_ON(ret);
		ret = btrfs_inc_extent_ref(trans, dest, new_bytenr, blocksize,
					0, dest->root_key.objectid, level - 1,
A
Arne Jansen 已提交
1869
					0, 1);
1870 1871 1872 1873
		BUG_ON(ret);

		ret = btrfs_free_extent(trans, src, new_bytenr, blocksize,
					path->nodes[level]->start,
A
Arne Jansen 已提交
1874 1875
					src->root_key.objectid, level - 1, 0,
					1);
1876 1877 1878 1879
		BUG_ON(ret);

		ret = btrfs_free_extent(trans, dest, old_bytenr, blocksize,
					0, dest->root_key.objectid, level - 1,
A
Arne Jansen 已提交
1880
					0, 1);
1881 1882 1883 1884 1885 1886 1887 1888 1889 1890 1891 1892 1893 1894 1895 1896 1897 1898 1899 1900 1901 1902 1903 1904 1905 1906 1907 1908 1909 1910 1911 1912 1913 1914 1915 1916 1917 1918 1919 1920 1921 1922 1923 1924 1925 1926 1927 1928 1929 1930 1931 1932 1933 1934 1935 1936 1937 1938 1939 1940 1941 1942 1943 1944 1945 1946 1947 1948 1949 1950 1951 1952 1953 1954 1955 1956 1957 1958 1959 1960 1961 1962 1963 1964 1965 1966 1967 1968 1969
		BUG_ON(ret);

		btrfs_unlock_up_safe(path, 0);

		ret = level;
		break;
	}
	btrfs_tree_unlock(parent);
	free_extent_buffer(parent);
	return ret;
}

/*
 * helper to find next relocated block in reloc tree
 */
static noinline_for_stack
int walk_up_reloc_tree(struct btrfs_root *root, struct btrfs_path *path,
		       int *level)
{
	struct extent_buffer *eb;
	int i;
	u64 last_snapshot;
	u32 nritems;

	last_snapshot = btrfs_root_last_snapshot(&root->root_item);

	for (i = 0; i < *level; i++) {
		free_extent_buffer(path->nodes[i]);
		path->nodes[i] = NULL;
	}

	for (i = *level; i < BTRFS_MAX_LEVEL && path->nodes[i]; i++) {
		eb = path->nodes[i];
		nritems = btrfs_header_nritems(eb);
		while (path->slots[i] + 1 < nritems) {
			path->slots[i]++;
			if (btrfs_node_ptr_generation(eb, path->slots[i]) <=
			    last_snapshot)
				continue;

			*level = i;
			return 0;
		}
		free_extent_buffer(path->nodes[i]);
		path->nodes[i] = NULL;
	}
	return 1;
}

/*
 * walk down reloc tree to find relocated block of lowest level
 */
static noinline_for_stack
int walk_down_reloc_tree(struct btrfs_root *root, struct btrfs_path *path,
			 int *level)
{
	struct extent_buffer *eb = NULL;
	int i;
	u64 bytenr;
	u64 ptr_gen = 0;
	u64 last_snapshot;
	u32 blocksize;
	u32 nritems;

	last_snapshot = btrfs_root_last_snapshot(&root->root_item);

	for (i = *level; i > 0; i--) {
		eb = path->nodes[i];
		nritems = btrfs_header_nritems(eb);
		while (path->slots[i] < nritems) {
			ptr_gen = btrfs_node_ptr_generation(eb, path->slots[i]);
			if (ptr_gen > last_snapshot)
				break;
			path->slots[i]++;
		}
		if (path->slots[i] >= nritems) {
			if (i == *level)
				break;
			*level = i + 1;
			return 0;
		}
		if (i == 1) {
			*level = i;
			return 0;
		}

		bytenr = btrfs_node_blockptr(eb, path->slots[i]);
		blocksize = btrfs_level_size(root, i - 1);
		eb = read_tree_block(root, bytenr, blocksize, ptr_gen);
1970 1971 1972 1973
		if (!eb || !extent_buffer_uptodate(eb)) {
			free_extent_buffer(eb);
			return -EIO;
		}
1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991
		BUG_ON(btrfs_header_level(eb) != i - 1);
		path->nodes[i - 1] = eb;
		path->slots[i - 1] = 0;
	}
	return 1;
}

/*
 * invalidate extent cache for file extents whose key in range of
 * [min_key, max_key)
 */
static int invalidate_extent_cache(struct btrfs_root *root,
				   struct btrfs_key *min_key,
				   struct btrfs_key *max_key)
{
	struct inode *inode = NULL;
	u64 objectid;
	u64 start, end;
L
Li Zefan 已提交
1992
	u64 ino;
1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004

	objectid = min_key->objectid;
	while (1) {
		cond_resched();
		iput(inode);

		if (objectid > max_key->objectid)
			break;

		inode = find_next_inode(root, objectid);
		if (!inode)
			break;
L
Li Zefan 已提交
2005
		ino = btrfs_ino(inode);
2006

L
Li Zefan 已提交
2007
		if (ino > max_key->objectid) {
2008 2009 2010 2011
			iput(inode);
			break;
		}

L
Li Zefan 已提交
2012
		objectid = ino + 1;
2013 2014 2015
		if (!S_ISREG(inode->i_mode))
			continue;

L
Li Zefan 已提交
2016
		if (unlikely(min_key->objectid == ino)) {
2017 2018 2019 2020 2021 2022 2023 2024 2025 2026 2027 2028
			if (min_key->type > BTRFS_EXTENT_DATA_KEY)
				continue;
			if (min_key->type < BTRFS_EXTENT_DATA_KEY)
				start = 0;
			else {
				start = min_key->offset;
				WARN_ON(!IS_ALIGNED(start, root->sectorsize));
			}
		} else {
			start = 0;
		}

L
Li Zefan 已提交
2029
		if (unlikely(max_key->objectid == ino)) {
2030 2031 2032 2033 2034 2035 2036 2037 2038 2039 2040 2041 2042 2043 2044 2045
			if (max_key->type < BTRFS_EXTENT_DATA_KEY)
				continue;
			if (max_key->type > BTRFS_EXTENT_DATA_KEY) {
				end = (u64)-1;
			} else {
				if (max_key->offset == 0)
					continue;
				end = max_key->offset;
				WARN_ON(!IS_ALIGNED(end, root->sectorsize));
				end--;
			}
		} else {
			end = (u64)-1;
		}

		/* the lock_extent waits for readpage to complete */
2046
		lock_extent(&BTRFS_I(inode)->io_tree, start, end);
2047
		btrfs_drop_extent_cache(inode, start, end, 1);
2048
		unlock_extent(&BTRFS_I(inode)->io_tree, start, end);
2049 2050 2051 2052 2053 2054 2055 2056 2057 2058 2059 2060 2061 2062 2063 2064 2065 2066 2067 2068 2069 2070 2071 2072 2073 2074 2075 2076 2077 2078 2079 2080
	}
	return 0;
}

static int find_next_key(struct btrfs_path *path, int level,
			 struct btrfs_key *key)

{
	while (level < BTRFS_MAX_LEVEL) {
		if (!path->nodes[level])
			break;
		if (path->slots[level] + 1 <
		    btrfs_header_nritems(path->nodes[level])) {
			btrfs_node_key_to_cpu(path->nodes[level], key,
					      path->slots[level] + 1);
			return 0;
		}
		level++;
	}
	return 1;
}

/*
 * merge the relocated tree blocks in reloc tree with corresponding
 * fs tree.
 */
static noinline_for_stack int merge_reloc_root(struct reloc_control *rc,
					       struct btrfs_root *root)
{
	LIST_HEAD(inode_list);
	struct btrfs_key key;
	struct btrfs_key next_key;
2081
	struct btrfs_trans_handle *trans = NULL;
2082 2083 2084
	struct btrfs_root *reloc_root;
	struct btrfs_root_item *root_item;
	struct btrfs_path *path;
2085
	struct extent_buffer *leaf;
2086 2087 2088 2089 2090
	int level;
	int max_level;
	int replaced = 0;
	int ret;
	int err = 0;
2091
	u32 min_reserved;
2092 2093 2094 2095

	path = btrfs_alloc_path();
	if (!path)
		return -ENOMEM;
J
Josef Bacik 已提交
2096
	path->reada = 1;
2097 2098 2099 2100 2101 2102 2103 2104 2105 2106 2107 2108 2109 2110 2111 2112

	reloc_root = root->reloc_root;
	root_item = &reloc_root->root_item;

	if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
		level = btrfs_root_level(root_item);
		extent_buffer_get(reloc_root->node);
		path->nodes[level] = reloc_root->node;
		path->slots[level] = 0;
	} else {
		btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);

		level = root_item->drop_level;
		BUG_ON(level == 0);
		path->lowest_level = level;
		ret = btrfs_search_slot(NULL, reloc_root, &key, path, 0, 0);
2113
		path->lowest_level = 0;
2114 2115 2116 2117 2118 2119 2120 2121 2122 2123 2124 2125
		if (ret < 0) {
			btrfs_free_path(path);
			return ret;
		}

		btrfs_node_key_to_cpu(path->nodes[level], &next_key,
				      path->slots[level]);
		WARN_ON(memcmp(&key, &next_key, sizeof(key)));

		btrfs_unlock_up_safe(path, 0);
	}

2126 2127
	min_reserved = root->nodesize * (BTRFS_MAX_LEVEL - 1) * 2;
	memset(&next_key, 0, sizeof(next_key));
2128

2129
	while (1) {
M
Miao Xie 已提交
2130 2131
		ret = btrfs_block_rsv_refill(root, rc->block_rsv, min_reserved,
					     BTRFS_RESERVE_FLUSH_ALL);
2132
		if (ret) {
2133 2134
			err = ret;
			goto out;
2135
		}
2136 2137 2138 2139 2140 2141 2142
		trans = btrfs_start_transaction(root, 0);
		if (IS_ERR(trans)) {
			err = PTR_ERR(trans);
			trans = NULL;
			goto out;
		}
		trans->block_rsv = rc->block_rsv;
2143 2144 2145 2146 2147 2148 2149 2150 2151 2152 2153 2154 2155 2156 2157 2158

		replaced = 0;
		max_level = level;

		ret = walk_down_reloc_tree(reloc_root, path, &level);
		if (ret < 0) {
			err = ret;
			goto out;
		}
		if (ret > 0)
			break;

		if (!find_next_key(path, level, &key) &&
		    btrfs_comp_cpu_keys(&next_key, &key) >= 0) {
			ret = 0;
		} else {
2159 2160
			ret = replace_path(trans, root, reloc_root, path,
					   &next_key, level, max_level);
2161 2162 2163 2164 2165 2166 2167 2168 2169 2170 2171 2172 2173 2174 2175 2176 2177 2178 2179 2180 2181 2182 2183 2184 2185 2186
		}
		if (ret < 0) {
			err = ret;
			goto out;
		}

		if (ret > 0) {
			level = ret;
			btrfs_node_key_to_cpu(path->nodes[level], &key,
					      path->slots[level]);
			replaced = 1;
		}

		ret = walk_up_reloc_tree(reloc_root, path, &level);
		if (ret > 0)
			break;

		BUG_ON(level == 0);
		/*
		 * save the merging progress in the drop_progress.
		 * this is OK since root refs == 1 in this case.
		 */
		btrfs_node_key(path->nodes[level], &root_item->drop_progress,
			       path->slots[level]);
		root_item->drop_level = level;

2187
		btrfs_end_transaction_throttle(trans, root);
2188
		trans = NULL;
2189

2190
		btrfs_btree_balance_dirty(root);
2191 2192 2193 2194 2195 2196 2197 2198 2199 2200 2201 2202 2203 2204 2205 2206 2207 2208 2209 2210 2211 2212 2213

		if (replaced && rc->stage == UPDATE_DATA_PTRS)
			invalidate_extent_cache(root, &key, &next_key);
	}

	/*
	 * handle the case only one block in the fs tree need to be
	 * relocated and the block is tree root.
	 */
	leaf = btrfs_lock_root_node(root);
	ret = btrfs_cow_block(trans, root, leaf, NULL, 0, &leaf);
	btrfs_tree_unlock(leaf);
	free_extent_buffer(leaf);
	if (ret < 0)
		err = ret;
out:
	btrfs_free_path(path);

	if (err == 0) {
		memset(&root_item->drop_progress, 0,
		       sizeof(root_item->drop_progress));
		root_item->drop_level = 0;
		btrfs_set_root_refs(root_item, 0);
2214
		btrfs_update_reloc_root(trans, root);
2215 2216
	}

2217 2218
	if (trans)
		btrfs_end_transaction_throttle(trans, root);
2219

2220
	btrfs_btree_balance_dirty(root);
2221 2222 2223 2224 2225 2226 2227

	if (replaced && rc->stage == UPDATE_DATA_PTRS)
		invalidate_extent_cache(root, &key, &next_key);

	return err;
}

2228 2229
static noinline_for_stack
int prepare_to_merge(struct reloc_control *rc, int err)
2230
{
2231
	struct btrfs_root *root = rc->extent_root;
2232
	struct btrfs_root *reloc_root;
2233 2234 2235 2236 2237
	struct btrfs_trans_handle *trans;
	LIST_HEAD(reloc_roots);
	u64 num_bytes = 0;
	int ret;

C
Chris Mason 已提交
2238
	mutex_lock(&root->fs_info->reloc_mutex);
2239 2240
	rc->merging_rsv_size += root->nodesize * (BTRFS_MAX_LEVEL - 1) * 2;
	rc->merging_rsv_size += rc->nodes_relocated * 2;
C
Chris Mason 已提交
2241 2242
	mutex_unlock(&root->fs_info->reloc_mutex);

2243 2244 2245
again:
	if (!err) {
		num_bytes = rc->merging_rsv_size;
M
Miao Xie 已提交
2246 2247
		ret = btrfs_block_rsv_add(root, rc->block_rsv, num_bytes,
					  BTRFS_RESERVE_FLUSH_ALL);
2248 2249 2250 2251
		if (ret)
			err = ret;
	}

2252
	trans = btrfs_join_transaction(rc->extent_root);
2253 2254 2255 2256 2257 2258
	if (IS_ERR(trans)) {
		if (!err)
			btrfs_block_rsv_release(rc->extent_root,
						rc->block_rsv, num_bytes);
		return PTR_ERR(trans);
	}
2259 2260 2261 2262 2263 2264 2265 2266 2267

	if (!err) {
		if (num_bytes != rc->merging_rsv_size) {
			btrfs_end_transaction(trans, rc->extent_root);
			btrfs_block_rsv_release(rc->extent_root,
						rc->block_rsv, num_bytes);
			goto again;
		}
	}
2268

2269 2270 2271 2272 2273 2274
	rc->merge_reloc_tree = 1;

	while (!list_empty(&rc->reloc_roots)) {
		reloc_root = list_entry(rc->reloc_roots.next,
					struct btrfs_root, root_list);
		list_del_init(&reloc_root->root_list);
2275 2276 2277 2278 2279 2280

		root = read_fs_root(reloc_root->fs_info,
				    reloc_root->root_key.offset);
		BUG_ON(IS_ERR(root));
		BUG_ON(root->reloc_root != reloc_root);

2281 2282 2283 2284 2285 2286
		/*
		 * set reference count to 1, so btrfs_recover_relocation
		 * knows it should resumes merging
		 */
		if (!err)
			btrfs_set_root_refs(&reloc_root->root_item, 1);
2287 2288
		btrfs_update_reloc_root(trans, root);

2289 2290
		list_add(&reloc_root->root_list, &reloc_roots);
	}
2291

2292
	list_splice(&reloc_roots, &rc->reloc_roots);
2293

2294 2295 2296 2297 2298
	if (!err)
		btrfs_commit_transaction(trans, rc->extent_root);
	else
		btrfs_end_transaction(trans, rc->extent_root);
	return err;
2299 2300
}

2301 2302 2303 2304 2305 2306 2307 2308
static noinline_for_stack
void free_reloc_roots(struct list_head *list)
{
	struct btrfs_root *reloc_root;

	while (!list_empty(list)) {
		reloc_root = list_entry(list->next, struct btrfs_root,
					root_list);
2309
		__del_reloc_root(reloc_root);
2310 2311 2312 2313 2314 2315
		free_extent_buffer(reloc_root->node);
		free_extent_buffer(reloc_root->commit_root);
		kfree(reloc_root);
	}
}

2316 2317
static noinline_for_stack
int merge_reloc_roots(struct reloc_control *rc)
2318
{
M
Miao Xie 已提交
2319
	struct btrfs_trans_handle *trans;
2320
	struct btrfs_root *root;
2321
	struct btrfs_root *reloc_root;
M
Miao Xie 已提交
2322 2323 2324
	u64 last_snap;
	u64 otransid;
	u64 objectid;
2325 2326
	LIST_HEAD(reloc_roots);
	int found = 0;
2327
	int ret = 0;
2328 2329
again:
	root = rc->extent_root;
C
Chris Mason 已提交
2330 2331 2332 2333 2334 2335 2336 2337

	/*
	 * this serializes us with btrfs_record_root_in_transaction,
	 * we have to make sure nobody is in the middle of
	 * adding their roots to the list while we are
	 * doing this splice
	 */
	mutex_lock(&root->fs_info->reloc_mutex);
2338
	list_splice_init(&rc->reloc_roots, &reloc_roots);
C
Chris Mason 已提交
2339
	mutex_unlock(&root->fs_info->reloc_mutex);
2340

2341 2342 2343 2344
	while (!list_empty(&reloc_roots)) {
		found = 1;
		reloc_root = list_entry(reloc_roots.next,
					struct btrfs_root, root_list);
2345

2346 2347 2348 2349 2350
		if (btrfs_root_refs(&reloc_root->root_item) > 0) {
			root = read_fs_root(reloc_root->fs_info,
					    reloc_root->root_key.offset);
			BUG_ON(IS_ERR(root));
			BUG_ON(root->reloc_root != reloc_root);
2351

2352
			ret = merge_reloc_root(rc, root);
2353
			if (ret) {
2354
				__del_reloc_root(reloc_root);
2355 2356 2357
				free_extent_buffer(reloc_root->node);
				free_extent_buffer(reloc_root->commit_root);
				kfree(reloc_root);
2358
				goto out;
2359
			}
2360 2361 2362
		} else {
			list_del_init(&reloc_root->root_list);
		}
M
Miao Xie 已提交
2363 2364 2365 2366 2367 2368 2369 2370 2371

		/*
		 * we keep the old last snapshod transid in rtranid when we
		 * created the relocation tree.
		 */
		last_snap = btrfs_root_rtransid(&reloc_root->root_item);
		otransid = btrfs_root_otransid(&reloc_root->root_item);
		objectid = reloc_root->root_key.offset;

2372
		ret = btrfs_drop_snapshot(reloc_root, rc->block_rsv, 0, 1);
2373 2374 2375 2376 2377
		if (ret < 0) {
			if (list_empty(&reloc_root->root_list))
				list_add_tail(&reloc_root->root_list,
					      &reloc_roots);
			goto out;
M
Miao Xie 已提交
2378 2379 2380 2381 2382 2383 2384 2385 2386 2387 2388 2389 2390 2391 2392 2393 2394 2395 2396 2397
		} else if (!ret) {
			/*
			 * recover the last snapshot tranid to avoid
			 * the space balance break NOCOW.
			 */
			root = read_fs_root(rc->extent_root->fs_info,
					    objectid);
			if (IS_ERR(root))
				continue;

			trans = btrfs_join_transaction(root);
			BUG_ON(IS_ERR(trans));

			/* Check if the fs/file tree was snapshoted or not. */
			if (btrfs_root_last_snapshot(&root->root_item) ==
			    otransid - 1)
				btrfs_set_root_last_snapshot(&root->root_item,
							     last_snap);
				
			btrfs_end_transaction(trans, root);
2398
		}
2399 2400
	}

2401 2402 2403 2404
	if (found) {
		found = 0;
		goto again;
	}
2405 2406 2407 2408 2409 2410 2411
out:
	if (ret) {
		btrfs_std_error(root->fs_info, ret);
		if (!list_empty(&reloc_roots))
			free_reloc_roots(&reloc_roots);
	}

2412
	BUG_ON(!RB_EMPTY_ROOT(&rc->reloc_root_tree.rb_root));
2413
	return ret;
2414 2415 2416 2417 2418 2419 2420 2421 2422 2423 2424 2425 2426 2427 2428 2429 2430 2431 2432 2433 2434 2435 2436 2437 2438 2439 2440 2441
}

static void free_block_list(struct rb_root *blocks)
{
	struct tree_block *block;
	struct rb_node *rb_node;
	while ((rb_node = rb_first(blocks))) {
		block = rb_entry(rb_node, struct tree_block, rb_node);
		rb_erase(rb_node, blocks);
		kfree(block);
	}
}

static int record_reloc_root_in_trans(struct btrfs_trans_handle *trans,
				      struct btrfs_root *reloc_root)
{
	struct btrfs_root *root;

	if (reloc_root->last_trans == trans->transid)
		return 0;

	root = read_fs_root(reloc_root->fs_info, reloc_root->root_key.offset);
	BUG_ON(IS_ERR(root));
	BUG_ON(root->reloc_root != reloc_root);

	return btrfs_record_root_in_trans(trans, root);
}

2442 2443 2444 2445 2446
static noinline_for_stack
struct btrfs_root *select_reloc_root(struct btrfs_trans_handle *trans,
				     struct reloc_control *rc,
				     struct backref_node *node,
				     struct backref_edge *edges[], int *nr)
2447 2448 2449
{
	struct backref_node *next;
	struct btrfs_root *root;
2450 2451
	int index = 0;

2452 2453 2454 2455 2456
	next = node;
	while (1) {
		cond_resched();
		next = walk_up_backref(next, edges, &index);
		root = next->root;
2457 2458
		BUG_ON(!root);
		BUG_ON(!root->ref_cows);
2459 2460 2461 2462 2463 2464

		if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) {
			record_reloc_root_in_trans(trans, root);
			break;
		}

2465 2466 2467 2468 2469 2470 2471 2472 2473 2474 2475
		btrfs_record_root_in_trans(trans, root);
		root = root->reloc_root;

		if (next->new_bytenr != root->node->start) {
			BUG_ON(next->new_bytenr);
			BUG_ON(!list_empty(&next->list));
			next->new_bytenr = root->node->start;
			next->root = root;
			list_add_tail(&next->list,
				      &rc->backref_cache.changed);
			__mark_block_processed(rc, next);
2476 2477 2478
			break;
		}

2479
		WARN_ON(1);
2480 2481 2482 2483 2484
		root = NULL;
		next = walk_down_backref(edges, &index);
		if (!next || next->level <= node->level)
			break;
	}
2485 2486
	if (!root)
		return NULL;
2487

2488 2489 2490 2491 2492 2493 2494 2495
	*nr = index;
	next = node;
	/* setup backref node path for btrfs_reloc_cow_block */
	while (1) {
		rc->backref_cache.path[next->level] = next;
		if (--index < 0)
			break;
		next = edges[index]->node[UPPER];
2496 2497 2498 2499
	}
	return root;
}

2500 2501 2502 2503 2504 2505
/*
 * select a tree root for relocation. return NULL if the block
 * is reference counted. we should use do_relocation() in this
 * case. return a tree root pointer if the block isn't reference
 * counted. return -ENOENT if the block is root of reloc tree.
 */
2506 2507 2508 2509
static noinline_for_stack
struct btrfs_root *select_one_root(struct btrfs_trans_handle *trans,
				   struct backref_node *node)
{
2510 2511 2512
	struct backref_node *next;
	struct btrfs_root *root;
	struct btrfs_root *fs_root = NULL;
2513
	struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2514 2515 2516 2517 2518 2519 2520 2521 2522
	int index = 0;

	next = node;
	while (1) {
		cond_resched();
		next = walk_up_backref(next, edges, &index);
		root = next->root;
		BUG_ON(!root);

L
Lucas De Marchi 已提交
2523
		/* no other choice for non-references counted tree */
2524 2525 2526 2527 2528 2529 2530 2531 2532 2533 2534 2535 2536 2537 2538 2539 2540
		if (!root->ref_cows)
			return root;

		if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID)
			fs_root = root;

		if (next != node)
			return NULL;

		next = walk_down_backref(edges, &index);
		if (!next || next->level <= node->level)
			break;
	}

	if (!fs_root)
		return ERR_PTR(-ENOENT);
	return fs_root;
2541 2542 2543
}

static noinline_for_stack
2544 2545
u64 calcu_metadata_size(struct reloc_control *rc,
			struct backref_node *node, int reserve)
2546
{
2547 2548 2549 2550 2551 2552 2553 2554 2555 2556 2557 2558 2559 2560 2561 2562 2563 2564 2565 2566 2567 2568 2569 2570 2571 2572 2573 2574
	struct backref_node *next = node;
	struct backref_edge *edge;
	struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
	u64 num_bytes = 0;
	int index = 0;

	BUG_ON(reserve && node->processed);

	while (next) {
		cond_resched();
		while (1) {
			if (next->processed && (reserve || next != node))
				break;

			num_bytes += btrfs_level_size(rc->extent_root,
						      next->level);

			if (list_empty(&next->upper))
				break;

			edge = list_entry(next->upper.next,
					  struct backref_edge, list[LOWER]);
			edges[index++] = edge;
			next = edge->node[UPPER];
		}
		next = walk_down_backref(edges, &index);
	}
	return num_bytes;
2575 2576
}

2577 2578 2579
static int reserve_metadata_space(struct btrfs_trans_handle *trans,
				  struct reloc_control *rc,
				  struct backref_node *node)
2580
{
2581 2582 2583 2584 2585
	struct btrfs_root *root = rc->extent_root;
	u64 num_bytes;
	int ret;

	num_bytes = calcu_metadata_size(rc, node, 1) * 2;
2586

2587
	trans->block_rsv = rc->block_rsv;
M
Miao Xie 已提交
2588 2589
	ret = btrfs_block_rsv_add(root, rc->block_rsv, num_bytes,
				  BTRFS_RESERVE_FLUSH_ALL);
2590 2591 2592 2593
	if (ret) {
		if (ret == -EAGAIN)
			rc->commit_transaction = 1;
		return ret;
2594
	}
2595 2596 2597 2598 2599 2600 2601 2602 2603

	return 0;
}

static void release_metadata_space(struct reloc_control *rc,
				   struct backref_node *node)
{
	u64 num_bytes = calcu_metadata_size(rc, node, 0) * 2;
	btrfs_block_rsv_release(rc->extent_root, rc->block_rsv, num_bytes);
2604 2605 2606 2607 2608 2609 2610 2611 2612 2613
}

/*
 * relocate a block tree, and then update pointers in upper level
 * blocks that reference the block to point to the new location.
 *
 * if called by link_to_upper, the block has already been relocated.
 * in that case this function just updates pointers.
 */
static int do_relocation(struct btrfs_trans_handle *trans,
2614
			 struct reloc_control *rc,
2615 2616 2617 2618 2619 2620 2621 2622 2623 2624 2625 2626 2627 2628 2629 2630 2631 2632 2633 2634
			 struct backref_node *node,
			 struct btrfs_key *key,
			 struct btrfs_path *path, int lowest)
{
	struct backref_node *upper;
	struct backref_edge *edge;
	struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
	struct btrfs_root *root;
	struct extent_buffer *eb;
	u32 blocksize;
	u64 bytenr;
	u64 generation;
	int nr;
	int slot;
	int ret;
	int err = 0;

	BUG_ON(lowest && node->eb);

	path->lowest_level = node->level + 1;
2635
	rc->backref_cache.path[node->level] = node;
2636 2637 2638 2639
	list_for_each_entry(edge, &node->upper, list[LOWER]) {
		cond_resched();

		upper = edge->node[UPPER];
2640 2641 2642 2643 2644 2645 2646 2647 2648 2649 2650 2651
		root = select_reloc_root(trans, rc, upper, edges, &nr);
		BUG_ON(!root);

		if (upper->eb && !upper->locked) {
			if (!lowest) {
				ret = btrfs_bin_search(upper->eb, key,
						       upper->level, &slot);
				BUG_ON(ret);
				bytenr = btrfs_node_blockptr(upper->eb, slot);
				if (node->eb->start == bytenr)
					goto next;
			}
2652
			drop_node_buffer(upper);
2653
		}
2654 2655 2656 2657 2658 2659 2660 2661 2662

		if (!upper->eb) {
			ret = btrfs_search_slot(trans, root, key, path, 0, 1);
			if (ret < 0) {
				err = ret;
				break;
			}
			BUG_ON(ret > 0);

2663 2664 2665 2666 2667 2668
			if (!upper->eb) {
				upper->eb = path->nodes[upper->level];
				path->nodes[upper->level] = NULL;
			} else {
				BUG_ON(upper->eb != path->nodes[upper->level]);
			}
2669

2670 2671
			upper->locked = 1;
			path->locks[upper->level] = 0;
2672

2673
			slot = path->slots[upper->level];
2674
			btrfs_release_path(path);
2675 2676 2677 2678 2679 2680 2681
		} else {
			ret = btrfs_bin_search(upper->eb, key, upper->level,
					       &slot);
			BUG_ON(ret);
		}

		bytenr = btrfs_node_blockptr(upper->eb, slot);
2682 2683
		if (lowest) {
			BUG_ON(bytenr != node->bytenr);
2684
		} else {
2685 2686
			if (node->eb->start == bytenr)
				goto next;
2687 2688 2689 2690 2691
		}

		blocksize = btrfs_level_size(root, node->level);
		generation = btrfs_node_ptr_generation(upper->eb, slot);
		eb = read_tree_block(root, bytenr, blocksize, generation);
2692 2693
		if (!eb || !extent_buffer_uptodate(eb)) {
			free_extent_buffer(eb);
2694 2695 2696
			err = -EIO;
			goto next;
		}
2697 2698 2699 2700 2701 2702
		btrfs_tree_lock(eb);
		btrfs_set_lock_blocking(eb);

		if (!node->eb) {
			ret = btrfs_cow_block(trans, root, eb, upper->eb,
					      slot, &eb);
2703 2704
			btrfs_tree_unlock(eb);
			free_extent_buffer(eb);
2705 2706
			if (ret < 0) {
				err = ret;
2707
				goto next;
2708
			}
2709
			BUG_ON(node->eb != eb);
2710 2711 2712 2713 2714 2715 2716 2717 2718 2719 2720
		} else {
			btrfs_set_node_blockptr(upper->eb, slot,
						node->eb->start);
			btrfs_set_node_ptr_generation(upper->eb, slot,
						      trans->transid);
			btrfs_mark_buffer_dirty(upper->eb);

			ret = btrfs_inc_extent_ref(trans, root,
						node->eb->start, blocksize,
						upper->eb->start,
						btrfs_header_owner(upper->eb),
A
Arne Jansen 已提交
2721
						node->level, 0, 1);
2722 2723 2724 2725 2726
			BUG_ON(ret);

			ret = btrfs_drop_subtree(trans, root, eb, upper->eb);
			BUG_ON(ret);
		}
2727 2728 2729 2730 2731 2732 2733
next:
		if (!upper->pending)
			drop_node_buffer(upper);
		else
			unlock_node_buffer(upper);
		if (err)
			break;
2734
	}
2735 2736 2737 2738 2739 2740 2741

	if (!err && node->pending) {
		drop_node_buffer(node);
		list_move_tail(&node->list, &rc->backref_cache.changed);
		node->pending = 0;
	}

2742
	path->lowest_level = 0;
2743
	BUG_ON(err == -ENOSPC);
2744 2745 2746 2747
	return err;
}

static int link_to_upper(struct btrfs_trans_handle *trans,
2748
			 struct reloc_control *rc,
2749 2750 2751 2752 2753 2754
			 struct backref_node *node,
			 struct btrfs_path *path)
{
	struct btrfs_key key;

	btrfs_node_key_to_cpu(node->eb, &key, 0);
2755
	return do_relocation(trans, rc, node, &key, path, 0);
2756 2757 2758
}

static int finish_pending_nodes(struct btrfs_trans_handle *trans,
2759 2760
				struct reloc_control *rc,
				struct btrfs_path *path, int err)
2761
{
2762 2763
	LIST_HEAD(list);
	struct backref_cache *cache = &rc->backref_cache;
2764 2765 2766 2767 2768 2769 2770
	struct backref_node *node;
	int level;
	int ret;

	for (level = 0; level < BTRFS_MAX_LEVEL; level++) {
		while (!list_empty(&cache->pending[level])) {
			node = list_entry(cache->pending[level].next,
2771 2772 2773
					  struct backref_node, list);
			list_move_tail(&node->list, &list);
			BUG_ON(!node->pending);
2774

2775 2776 2777 2778 2779
			if (!err) {
				ret = link_to_upper(trans, rc, node, path);
				if (ret < 0)
					err = ret;
			}
2780
		}
2781
		list_splice_init(&list, &cache->pending[level]);
2782 2783 2784 2785 2786
	}
	return err;
}

static void mark_block_processed(struct reloc_control *rc,
2787 2788 2789 2790 2791 2792 2793 2794
				 u64 bytenr, u32 blocksize)
{
	set_extent_bits(&rc->processed_blocks, bytenr, bytenr + blocksize - 1,
			EXTENT_DIRTY, GFP_NOFS);
}

static void __mark_block_processed(struct reloc_control *rc,
				   struct backref_node *node)
2795 2796 2797 2798 2799
{
	u32 blocksize;
	if (node->level == 0 ||
	    in_block_group(node->bytenr, rc->block_group)) {
		blocksize = btrfs_level_size(rc->extent_root, node->level);
2800
		mark_block_processed(rc, node->bytenr, blocksize);
2801 2802 2803 2804 2805 2806 2807 2808 2809 2810 2811 2812 2813 2814 2815 2816 2817 2818 2819 2820 2821 2822
	}
	node->processed = 1;
}

/*
 * mark a block and all blocks directly/indirectly reference the block
 * as processed.
 */
static void update_processed_blocks(struct reloc_control *rc,
				    struct backref_node *node)
{
	struct backref_node *next = node;
	struct backref_edge *edge;
	struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
	int index = 0;

	while (next) {
		cond_resched();
		while (1) {
			if (next->processed)
				break;

2823
			__mark_block_processed(rc, next);
2824 2825 2826 2827 2828 2829 2830 2831 2832 2833 2834 2835 2836

			if (list_empty(&next->upper))
				break;

			edge = list_entry(next->upper.next,
					  struct backref_edge, list[LOWER]);
			edges[index++] = edge;
			next = edge->node[UPPER];
		}
		next = walk_down_backref(edges, &index);
	}
}

2837 2838 2839 2840 2841 2842 2843
static int tree_block_processed(u64 bytenr, u32 blocksize,
				struct reloc_control *rc)
{
	if (test_range_bit(&rc->processed_blocks, bytenr,
			   bytenr + blocksize - 1, EXTENT_DIRTY, 1, NULL))
		return 1;
	return 0;
2844 2845 2846 2847 2848 2849 2850 2851 2852 2853
}

static int get_tree_block_key(struct reloc_control *rc,
			      struct tree_block *block)
{
	struct extent_buffer *eb;

	BUG_ON(block->key_ready);
	eb = read_tree_block(rc->extent_root, block->bytenr,
			     block->key.objectid, block->key.offset);
2854 2855 2856 2857
	if (!eb || !extent_buffer_uptodate(eb)) {
		free_extent_buffer(eb);
		return -EIO;
	}
2858 2859 2860 2861 2862 2863 2864 2865 2866 2867 2868 2869 2870 2871
	WARN_ON(btrfs_header_level(eb) != block->level);
	if (block->level == 0)
		btrfs_item_key_to_cpu(eb, &block->key, 0);
	else
		btrfs_node_key_to_cpu(eb, &block->key, 0);
	free_extent_buffer(eb);
	block->key_ready = 1;
	return 0;
}

static int reada_tree_block(struct reloc_control *rc,
			    struct tree_block *block)
{
	BUG_ON(block->key_ready);
2872 2873 2874 2875 2876 2877 2878
	if (block->key.type == BTRFS_METADATA_ITEM_KEY)
		readahead_tree_block(rc->extent_root, block->bytenr,
				     block->key.objectid,
				     rc->extent_root->leafsize);
	else
		readahead_tree_block(rc->extent_root, block->bytenr,
				     block->key.objectid, block->key.offset);
2879 2880 2881 2882 2883 2884 2885 2886 2887 2888 2889 2890 2891
	return 0;
}

/*
 * helper function to relocate a tree block
 */
static int relocate_tree_block(struct btrfs_trans_handle *trans,
				struct reloc_control *rc,
				struct backref_node *node,
				struct btrfs_key *key,
				struct btrfs_path *path)
{
	struct btrfs_root *root;
2892 2893 2894 2895 2896
	int release = 0;
	int ret = 0;

	if (!node)
		return 0;
2897

2898
	BUG_ON(node->processed);
2899
	root = select_one_root(trans, node);
2900
	if (root == ERR_PTR(-ENOENT)) {
2901
		update_processed_blocks(rc, node);
2902
		goto out;
2903 2904
	}

2905 2906 2907
	if (!root || root->ref_cows) {
		ret = reserve_metadata_space(trans, rc, node);
		if (ret)
2908
			goto out;
2909
		release = 1;
2910 2911
	}

2912 2913 2914 2915 2916 2917 2918 2919 2920 2921 2922 2923
	if (root) {
		if (root->ref_cows) {
			BUG_ON(node->new_bytenr);
			BUG_ON(!list_empty(&node->list));
			btrfs_record_root_in_trans(trans, root);
			root = root->reloc_root;
			node->new_bytenr = root->node->start;
			node->root = root;
			list_add_tail(&node->list, &rc->backref_cache.changed);
		} else {
			path->lowest_level = node->level;
			ret = btrfs_search_slot(trans, root, key, path, 0, 1);
2924
			btrfs_release_path(path);
2925 2926 2927 2928 2929 2930 2931 2932
			if (ret > 0)
				ret = 0;
		}
		if (!ret)
			update_processed_blocks(rc, node);
	} else {
		ret = do_relocation(trans, rc, node, key, path, 1);
	}
2933
out:
2934 2935 2936 2937 2938
	if (ret || node->level == 0 || node->cowonly) {
		if (release)
			release_metadata_space(rc, node);
		remove_backref_node(&rc->backref_cache, node);
	}
2939 2940 2941 2942 2943 2944 2945 2946 2947 2948 2949 2950 2951 2952 2953 2954 2955 2956
	return ret;
}

/*
 * relocate a list of blocks
 */
static noinline_for_stack
int relocate_tree_blocks(struct btrfs_trans_handle *trans,
			 struct reloc_control *rc, struct rb_root *blocks)
{
	struct backref_node *node;
	struct btrfs_path *path;
	struct tree_block *block;
	struct rb_node *rb_node;
	int ret;
	int err = 0;

	path = btrfs_alloc_path();
2957 2958
	if (!path) {
		err = -ENOMEM;
2959
		goto out_free_blocks;
2960
	}
2961 2962 2963 2964 2965 2966 2967 2968 2969 2970 2971 2972

	rb_node = rb_first(blocks);
	while (rb_node) {
		block = rb_entry(rb_node, struct tree_block, rb_node);
		if (!block->key_ready)
			reada_tree_block(rc, block);
		rb_node = rb_next(rb_node);
	}

	rb_node = rb_first(blocks);
	while (rb_node) {
		block = rb_entry(rb_node, struct tree_block, rb_node);
2973 2974 2975 2976 2977
		if (!block->key_ready) {
			err = get_tree_block_key(rc, block);
			if (err)
				goto out_free_path;
		}
2978 2979 2980 2981 2982 2983 2984
		rb_node = rb_next(rb_node);
	}

	rb_node = rb_first(blocks);
	while (rb_node) {
		block = rb_entry(rb_node, struct tree_block, rb_node);

2985
		node = build_backref_tree(rc, &block->key,
2986 2987 2988 2989 2990 2991 2992 2993 2994
					  block->level, block->bytenr);
		if (IS_ERR(node)) {
			err = PTR_ERR(node);
			goto out;
		}

		ret = relocate_tree_block(trans, rc, node, &block->key,
					  path);
		if (ret < 0) {
2995 2996
			if (ret != -EAGAIN || rb_node == rb_first(blocks))
				err = ret;
2997 2998 2999 3000 3001
			goto out;
		}
		rb_node = rb_next(rb_node);
	}
out:
3002
	err = finish_pending_nodes(trans, rc, path, err);
3003

3004
out_free_path:
3005
	btrfs_free_path(path);
3006
out_free_blocks:
3007
	free_block_list(blocks);
3008 3009 3010
	return err;
}

3011 3012 3013 3014 3015 3016 3017 3018 3019 3020 3021 3022 3023 3024 3025 3026 3027 3028 3029 3030 3031 3032 3033 3034 3035 3036 3037
static noinline_for_stack
int prealloc_file_extent_cluster(struct inode *inode,
				 struct file_extent_cluster *cluster)
{
	u64 alloc_hint = 0;
	u64 start;
	u64 end;
	u64 offset = BTRFS_I(inode)->index_cnt;
	u64 num_bytes;
	int nr = 0;
	int ret = 0;

	BUG_ON(cluster->start != cluster->boundary[0]);
	mutex_lock(&inode->i_mutex);

	ret = btrfs_check_data_free_space(inode, cluster->end +
					  1 - cluster->start);
	if (ret)
		goto out;

	while (nr < cluster->nr) {
		start = cluster->boundary[nr] - offset;
		if (nr + 1 < cluster->nr)
			end = cluster->boundary[nr + 1] - 1 - offset;
		else
			end = cluster->end - offset;

3038
		lock_extent(&BTRFS_I(inode)->io_tree, start, end);
3039 3040 3041 3042
		num_bytes = end + 1 - start;
		ret = btrfs_prealloc_file_range(inode, 0, start,
						num_bytes, num_bytes,
						end + 1, &alloc_hint);
3043
		unlock_extent(&BTRFS_I(inode)->io_tree, start, end);
3044 3045 3046 3047 3048 3049 3050 3051 3052 3053 3054
		if (ret)
			break;
		nr++;
	}
	btrfs_free_reserved_data_space(inode, cluster->end +
				       1 - cluster->start);
out:
	mutex_unlock(&inode->i_mutex);
	return ret;
}

3055
static noinline_for_stack
3056 3057 3058 3059 3060 3061 3062 3063
int setup_extent_mapping(struct inode *inode, u64 start, u64 end,
			 u64 block_start)
{
	struct btrfs_root *root = BTRFS_I(inode)->root;
	struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
	struct extent_map *em;
	int ret = 0;

3064
	em = alloc_extent_map();
3065 3066 3067 3068 3069 3070 3071 3072 3073 3074
	if (!em)
		return -ENOMEM;

	em->start = start;
	em->len = end + 1 - start;
	em->block_len = em->len;
	em->block_start = block_start;
	em->bdev = root->fs_info->fs_devices->latest_bdev;
	set_bit(EXTENT_FLAG_PINNED, &em->flags);

3075
	lock_extent(&BTRFS_I(inode)->io_tree, start, end);
3076 3077
	while (1) {
		write_lock(&em_tree->lock);
J
Josef Bacik 已提交
3078
		ret = add_extent_mapping(em_tree, em, 0);
3079 3080 3081 3082 3083 3084 3085
		write_unlock(&em_tree->lock);
		if (ret != -EEXIST) {
			free_extent_map(em);
			break;
		}
		btrfs_drop_extent_cache(inode, start, end, 0);
	}
3086
	unlock_extent(&BTRFS_I(inode)->io_tree, start, end);
3087 3088 3089 3090 3091
	return ret;
}

static int relocate_file_extent_cluster(struct inode *inode,
					struct file_extent_cluster *cluster)
3092 3093 3094
{
	u64 page_start;
	u64 page_end;
3095 3096
	u64 offset = BTRFS_I(inode)->index_cnt;
	unsigned long index;
3097 3098 3099
	unsigned long last_index;
	struct page *page;
	struct file_ra_state *ra;
3100
	gfp_t mask = btrfs_alloc_write_mask(inode->i_mapping);
3101
	int nr = 0;
3102 3103
	int ret = 0;

3104 3105 3106
	if (!cluster->nr)
		return 0;

3107 3108 3109 3110
	ra = kzalloc(sizeof(*ra), GFP_NOFS);
	if (!ra)
		return -ENOMEM;

3111 3112 3113
	ret = prealloc_file_extent_cluster(inode, cluster);
	if (ret)
		goto out;
3114

3115
	file_ra_state_init(ra, inode->i_mapping);
3116

3117 3118
	ret = setup_extent_mapping(inode, cluster->start - offset,
				   cluster->end - offset, cluster->start);
3119
	if (ret)
3120
		goto out;
3121

3122 3123
	index = (cluster->start - offset) >> PAGE_CACHE_SHIFT;
	last_index = (cluster->end - offset) >> PAGE_CACHE_SHIFT;
3124
	while (index <= last_index) {
3125 3126 3127 3128
		ret = btrfs_delalloc_reserve_metadata(inode, PAGE_CACHE_SIZE);
		if (ret)
			goto out;

3129
		page = find_lock_page(inode->i_mapping, index);
3130
		if (!page) {
3131 3132 3133
			page_cache_sync_readahead(inode->i_mapping,
						  ra, NULL, index,
						  last_index + 1 - index);
3134
			page = find_or_create_page(inode->i_mapping, index,
3135
						   mask);
3136
			if (!page) {
3137 3138
				btrfs_delalloc_release_metadata(inode,
							PAGE_CACHE_SIZE);
3139
				ret = -ENOMEM;
3140
				goto out;
3141
			}
3142
		}
3143 3144 3145 3146 3147 3148 3149

		if (PageReadahead(page)) {
			page_cache_async_readahead(inode->i_mapping,
						   ra, NULL, page, index,
						   last_index + 1 - index);
		}

3150 3151 3152 3153 3154 3155
		if (!PageUptodate(page)) {
			btrfs_readpage(NULL, page);
			lock_page(page);
			if (!PageUptodate(page)) {
				unlock_page(page);
				page_cache_release(page);
3156 3157
				btrfs_delalloc_release_metadata(inode,
							PAGE_CACHE_SIZE);
3158
				ret = -EIO;
3159
				goto out;
3160 3161 3162
			}
		}

M
Miao Xie 已提交
3163
		page_start = page_offset(page);
3164
		page_end = page_start + PAGE_CACHE_SIZE - 1;
3165

3166
		lock_extent(&BTRFS_I(inode)->io_tree, page_start, page_end);
3167

3168 3169
		set_page_extent_mapped(page);

3170 3171 3172 3173
		if (nr < cluster->nr &&
		    page_start + offset == cluster->boundary[nr]) {
			set_extent_bits(&BTRFS_I(inode)->io_tree,
					page_start, page_end,
3174
					EXTENT_BOUNDARY, GFP_NOFS);
3175 3176
			nr++;
		}
3177

3178
		btrfs_set_extent_delalloc(inode, page_start, page_end, NULL);
3179 3180
		set_page_dirty(page);

3181
		unlock_extent(&BTRFS_I(inode)->io_tree,
3182
			      page_start, page_end);
3183 3184
		unlock_page(page);
		page_cache_release(page);
3185 3186

		index++;
3187 3188
		balance_dirty_pages_ratelimited(inode->i_mapping);
		btrfs_throttle(BTRFS_I(inode)->root);
3189
	}
3190
	WARN_ON(nr != cluster->nr);
3191
out:
3192 3193 3194 3195 3196
	kfree(ra);
	return ret;
}

static noinline_for_stack
3197 3198
int relocate_data_extent(struct inode *inode, struct btrfs_key *extent_key,
			 struct file_extent_cluster *cluster)
3199
{
3200
	int ret;
3201

3202 3203 3204 3205 3206
	if (cluster->nr > 0 && extent_key->objectid != cluster->end + 1) {
		ret = relocate_file_extent_cluster(inode, cluster);
		if (ret)
			return ret;
		cluster->nr = 0;
3207 3208
	}

3209 3210 3211 3212 3213 3214 3215 3216 3217 3218 3219 3220 3221 3222 3223
	if (!cluster->nr)
		cluster->start = extent_key->objectid;
	else
		BUG_ON(cluster->nr >= MAX_EXTENTS);
	cluster->end = extent_key->objectid + extent_key->offset - 1;
	cluster->boundary[cluster->nr] = extent_key->objectid;
	cluster->nr++;

	if (cluster->nr >= MAX_EXTENTS) {
		ret = relocate_file_extent_cluster(inode, cluster);
		if (ret)
			return ret;
		cluster->nr = 0;
	}
	return 0;
3224 3225 3226 3227 3228 3229 3230 3231 3232 3233 3234 3235 3236 3237 3238 3239 3240 3241 3242 3243 3244 3245 3246 3247 3248 3249 3250 3251 3252 3253 3254 3255 3256 3257 3258 3259 3260 3261 3262 3263 3264 3265 3266 3267 3268 3269 3270 3271 3272 3273 3274 3275 3276 3277 3278 3279 3280 3281 3282 3283
}

#ifdef BTRFS_COMPAT_EXTENT_TREE_V0
static int get_ref_objectid_v0(struct reloc_control *rc,
			       struct btrfs_path *path,
			       struct btrfs_key *extent_key,
			       u64 *ref_objectid, int *path_change)
{
	struct btrfs_key key;
	struct extent_buffer *leaf;
	struct btrfs_extent_ref_v0 *ref0;
	int ret;
	int slot;

	leaf = path->nodes[0];
	slot = path->slots[0];
	while (1) {
		if (slot >= btrfs_header_nritems(leaf)) {
			ret = btrfs_next_leaf(rc->extent_root, path);
			if (ret < 0)
				return ret;
			BUG_ON(ret > 0);
			leaf = path->nodes[0];
			slot = path->slots[0];
			if (path_change)
				*path_change = 1;
		}
		btrfs_item_key_to_cpu(leaf, &key, slot);
		if (key.objectid != extent_key->objectid)
			return -ENOENT;

		if (key.type != BTRFS_EXTENT_REF_V0_KEY) {
			slot++;
			continue;
		}
		ref0 = btrfs_item_ptr(leaf, slot,
				struct btrfs_extent_ref_v0);
		*ref_objectid = btrfs_ref_objectid_v0(leaf, ref0);
		break;
	}
	return 0;
}
#endif

/*
 * helper to add a tree block to the list.
 * the major work is getting the generation and level of the block
 */
static int add_tree_block(struct reloc_control *rc,
			  struct btrfs_key *extent_key,
			  struct btrfs_path *path,
			  struct rb_root *blocks)
{
	struct extent_buffer *eb;
	struct btrfs_extent_item *ei;
	struct btrfs_tree_block_info *bi;
	struct tree_block *block;
	struct rb_node *rb_node;
	u32 item_size;
	int level = -1;
3284
	u64 generation;
3285 3286 3287 3288

	eb =  path->nodes[0];
	item_size = btrfs_item_size_nr(eb, path->slots[0]);

3289 3290
	if (extent_key->type == BTRFS_METADATA_ITEM_KEY ||
	    item_size >= sizeof(*ei) + sizeof(*bi)) {
3291 3292
		ei = btrfs_item_ptr(eb, path->slots[0],
				struct btrfs_extent_item);
3293 3294 3295 3296 3297 3298
		if (extent_key->type == BTRFS_EXTENT_ITEM_KEY) {
			bi = (struct btrfs_tree_block_info *)(ei + 1);
			level = btrfs_tree_block_level(eb, bi);
		} else {
			level = (int)extent_key->offset;
		}
3299 3300 3301 3302 3303 3304 3305 3306 3307
		generation = btrfs_extent_generation(eb, ei);
	} else {
#ifdef BTRFS_COMPAT_EXTENT_TREE_V0
		u64 ref_owner;
		int ret;

		BUG_ON(item_size != sizeof(struct btrfs_extent_item_v0));
		ret = get_ref_objectid_v0(rc, path, extent_key,
					  &ref_owner, NULL);
3308 3309
		if (ret < 0)
			return ret;
3310 3311 3312 3313 3314 3315 3316 3317 3318
		BUG_ON(ref_owner >= BTRFS_MAX_LEVEL);
		level = (int)ref_owner;
		/* FIXME: get real generation */
		generation = 0;
#else
		BUG();
#endif
	}

3319
	btrfs_release_path(path);
3320 3321 3322 3323 3324 3325 3326 3327

	BUG_ON(level == -1);

	block = kmalloc(sizeof(*block), GFP_NOFS);
	if (!block)
		return -ENOMEM;

	block->bytenr = extent_key->objectid;
3328
	block->key.objectid = rc->extent_root->leafsize;
3329 3330 3331 3332 3333
	block->key.offset = generation;
	block->level = level;
	block->key_ready = 0;

	rb_node = tree_insert(blocks, block->bytenr, &block->rb_node);
3334 3335
	if (rb_node)
		backref_tree_panic(rb_node, -EEXIST, block->bytenr);
3336 3337 3338 3339 3340 3341 3342 3343 3344 3345 3346 3347 3348 3349

	return 0;
}

/*
 * helper to add tree blocks for backref of type BTRFS_SHARED_DATA_REF_KEY
 */
static int __add_tree_block(struct reloc_control *rc,
			    u64 bytenr, u32 blocksize,
			    struct rb_root *blocks)
{
	struct btrfs_path *path;
	struct btrfs_key key;
	int ret;
3350 3351
	bool skinny = btrfs_fs_incompat(rc->extent_root->fs_info,
					SKINNY_METADATA);
3352 3353 3354 3355 3356 3357 3358 3359 3360 3361

	if (tree_block_processed(bytenr, blocksize, rc))
		return 0;

	if (tree_search(blocks, bytenr))
		return 0;

	path = btrfs_alloc_path();
	if (!path)
		return -ENOMEM;
3362
again:
3363
	key.objectid = bytenr;
3364 3365 3366 3367 3368 3369 3370
	if (skinny) {
		key.type = BTRFS_METADATA_ITEM_KEY;
		key.offset = (u64)-1;
	} else {
		key.type = BTRFS_EXTENT_ITEM_KEY;
		key.offset = blocksize;
	}
3371 3372 3373 3374 3375 3376 3377

	path->search_commit_root = 1;
	path->skip_locking = 1;
	ret = btrfs_search_slot(NULL, rc->extent_root, &key, path, 0, 0);
	if (ret < 0)
		goto out;

3378 3379 3380 3381 3382 3383 3384 3385 3386 3387 3388 3389 3390 3391 3392 3393 3394
	if (ret > 0 && skinny) {
		if (path->slots[0]) {
			path->slots[0]--;
			btrfs_item_key_to_cpu(path->nodes[0], &key,
					      path->slots[0]);
			if (key.objectid == bytenr &&
			    (key.type == BTRFS_METADATA_ITEM_KEY ||
			     (key.type == BTRFS_EXTENT_ITEM_KEY &&
			      key.offset == blocksize)))
				ret = 0;
		}

		if (ret) {
			skinny = false;
			btrfs_release_path(path);
			goto again;
		}
3395 3396 3397
	}
	BUG_ON(ret);

3398 3399 3400 3401 3402 3403 3404 3405 3406 3407 3408 3409 3410 3411 3412 3413 3414 3415 3416
	ret = add_tree_block(rc, &key, path, blocks);
out:
	btrfs_free_path(path);
	return ret;
}

/*
 * helper to check if the block use full backrefs for pointers in it
 */
static int block_use_full_backref(struct reloc_control *rc,
				  struct extent_buffer *eb)
{
	u64 flags;
	int ret;

	if (btrfs_header_flag(eb, BTRFS_HEADER_FLAG_RELOC) ||
	    btrfs_header_backref_rev(eb) < BTRFS_MIXED_BACKREF_REV)
		return 1;

3417
	ret = btrfs_lookup_extent_info(NULL, rc->extent_root,
3418 3419
				       eb->start, btrfs_header_level(eb), 1,
				       NULL, &flags);
3420 3421 3422 3423 3424 3425 3426 3427 3428
	BUG_ON(ret);

	if (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF)
		ret = 1;
	else
		ret = 0;
	return ret;
}

3429 3430 3431 3432 3433 3434 3435 3436 3437 3438 3439 3440 3441 3442 3443 3444
static int delete_block_group_cache(struct btrfs_fs_info *fs_info,
				    struct inode *inode, u64 ino)
{
	struct btrfs_key key;
	struct btrfs_root *root = fs_info->tree_root;
	struct btrfs_trans_handle *trans;
	int ret = 0;

	if (inode)
		goto truncate;

	key.objectid = ino;
	key.type = BTRFS_INODE_ITEM_KEY;
	key.offset = 0;

	inode = btrfs_iget(fs_info->sb, &key, root, NULL);
3445 3446
	if (IS_ERR(inode) || is_bad_inode(inode)) {
		if (!IS_ERR(inode))
3447 3448 3449 3450 3451
			iput(inode);
		return -ENOENT;
	}

truncate:
3452 3453 3454 3455 3456
	ret = btrfs_check_trunc_cache_free_space(root,
						 &fs_info->global_block_rsv);
	if (ret)
		goto out;

3457
	trans = btrfs_join_transaction(root);
3458
	if (IS_ERR(trans)) {
3459
		ret = PTR_ERR(trans);
3460 3461 3462
		goto out;
	}

3463
	ret = btrfs_truncate_free_space_cache(root, trans, inode);
3464 3465

	btrfs_end_transaction(trans, root);
3466
	btrfs_btree_balance_dirty(root);
3467 3468 3469 3470 3471
out:
	iput(inode);
	return ret;
}

3472 3473 3474 3475 3476 3477 3478 3479 3480 3481 3482 3483 3484 3485 3486 3487 3488 3489 3490 3491 3492 3493 3494 3495 3496 3497 3498 3499 3500 3501 3502
/*
 * helper to add tree blocks for backref of type BTRFS_EXTENT_DATA_REF_KEY
 * this function scans fs tree to find blocks reference the data extent
 */
static int find_data_references(struct reloc_control *rc,
				struct btrfs_key *extent_key,
				struct extent_buffer *leaf,
				struct btrfs_extent_data_ref *ref,
				struct rb_root *blocks)
{
	struct btrfs_path *path;
	struct tree_block *block;
	struct btrfs_root *root;
	struct btrfs_file_extent_item *fi;
	struct rb_node *rb_node;
	struct btrfs_key key;
	u64 ref_root;
	u64 ref_objectid;
	u64 ref_offset;
	u32 ref_count;
	u32 nritems;
	int err = 0;
	int added = 0;
	int counted;
	int ret;

	ref_root = btrfs_extent_data_ref_root(leaf, ref);
	ref_objectid = btrfs_extent_data_ref_objectid(leaf, ref);
	ref_offset = btrfs_extent_data_ref_offset(leaf, ref);
	ref_count = btrfs_extent_data_ref_count(leaf, ref);

3503 3504 3505 3506 3507 3508 3509 3510 3511 3512 3513 3514 3515 3516 3517
	/*
	 * This is an extent belonging to the free space cache, lets just delete
	 * it and redo the search.
	 */
	if (ref_root == BTRFS_ROOT_TREE_OBJECTID) {
		ret = delete_block_group_cache(rc->extent_root->fs_info,
					       NULL, ref_objectid);
		if (ret != -ENOENT)
			return ret;
		ret = 0;
	}

	path = btrfs_alloc_path();
	if (!path)
		return -ENOMEM;
J
Josef Bacik 已提交
3518
	path->reada = 1;
3519

3520 3521 3522 3523 3524 3525 3526 3527
	root = read_fs_root(rc->extent_root->fs_info, ref_root);
	if (IS_ERR(root)) {
		err = PTR_ERR(root);
		goto out;
	}

	key.objectid = ref_objectid;
	key.type = BTRFS_EXTENT_DATA_KEY;
3528 3529 3530 3531
	if (ref_offset > ((u64)-1 << 32))
		key.offset = 0;
	else
		key.offset = ref_offset;
3532 3533 3534 3535 3536 3537 3538 3539 3540 3541 3542 3543 3544 3545 3546 3547 3548 3549 3550 3551 3552 3553 3554 3555 3556 3557 3558 3559 3560 3561 3562 3563 3564 3565

	path->search_commit_root = 1;
	path->skip_locking = 1;
	ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
	if (ret < 0) {
		err = ret;
		goto out;
	}

	leaf = path->nodes[0];
	nritems = btrfs_header_nritems(leaf);
	/*
	 * the references in tree blocks that use full backrefs
	 * are not counted in
	 */
	if (block_use_full_backref(rc, leaf))
		counted = 0;
	else
		counted = 1;
	rb_node = tree_search(blocks, leaf->start);
	if (rb_node) {
		if (counted)
			added = 1;
		else
			path->slots[0] = nritems;
	}

	while (ref_count > 0) {
		while (path->slots[0] >= nritems) {
			ret = btrfs_next_leaf(root, path);
			if (ret < 0) {
				err = ret;
				goto out;
			}
3566
			if (WARN_ON(ret > 0))
3567 3568 3569 3570 3571 3572 3573 3574 3575 3576 3577 3578 3579 3580 3581 3582 3583 3584 3585 3586
				goto out;

			leaf = path->nodes[0];
			nritems = btrfs_header_nritems(leaf);
			added = 0;

			if (block_use_full_backref(rc, leaf))
				counted = 0;
			else
				counted = 1;
			rb_node = tree_search(blocks, leaf->start);
			if (rb_node) {
				if (counted)
					added = 1;
				else
					path->slots[0] = nritems;
			}
		}

		btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3587 3588
		if (WARN_ON(key.objectid != ref_objectid ||
		    key.type != BTRFS_EXTENT_DATA_KEY))
3589 3590 3591 3592 3593 3594 3595 3596 3597 3598 3599 3600 3601 3602 3603 3604 3605 3606 3607 3608 3609 3610 3611 3612 3613 3614 3615 3616 3617 3618 3619 3620 3621 3622
			break;

		fi = btrfs_item_ptr(leaf, path->slots[0],
				    struct btrfs_file_extent_item);

		if (btrfs_file_extent_type(leaf, fi) ==
		    BTRFS_FILE_EXTENT_INLINE)
			goto next;

		if (btrfs_file_extent_disk_bytenr(leaf, fi) !=
		    extent_key->objectid)
			goto next;

		key.offset -= btrfs_file_extent_offset(leaf, fi);
		if (key.offset != ref_offset)
			goto next;

		if (counted)
			ref_count--;
		if (added)
			goto next;

		if (!tree_block_processed(leaf->start, leaf->len, rc)) {
			block = kmalloc(sizeof(*block), GFP_NOFS);
			if (!block) {
				err = -ENOMEM;
				break;
			}
			block->bytenr = leaf->start;
			btrfs_item_key_to_cpu(leaf, &block->key, 0);
			block->level = 0;
			block->key_ready = 1;
			rb_node = tree_insert(blocks, block->bytenr,
					      &block->rb_node);
3623 3624 3625
			if (rb_node)
				backref_tree_panic(rb_node, -EEXIST,
						   block->bytenr);
3626 3627 3628 3629 3630 3631 3632 3633 3634 3635 3636 3637 3638 3639 3640
		}
		if (counted)
			added = 1;
		else
			path->slots[0] = nritems;
next:
		path->slots[0]++;

	}
out:
	btrfs_free_path(path);
	return err;
}

/*
L
Liu Bo 已提交
3641
 * helper to find all tree blocks that reference a given data extent
3642 3643 3644 3645 3646 3647 3648 3649 3650 3651 3652 3653 3654
 */
static noinline_for_stack
int add_data_references(struct reloc_control *rc,
			struct btrfs_key *extent_key,
			struct btrfs_path *path,
			struct rb_root *blocks)
{
	struct btrfs_key key;
	struct extent_buffer *eb;
	struct btrfs_extent_data_ref *dref;
	struct btrfs_extent_inline_ref *iref;
	unsigned long ptr;
	unsigned long end;
3655
	u32 blocksize = btrfs_level_size(rc->extent_root, 0);
3656
	int ret = 0;
3657 3658 3659 3660 3661 3662 3663 3664 3665 3666 3667 3668 3669 3670 3671 3672 3673 3674 3675 3676 3677 3678 3679 3680 3681 3682
	int err = 0;

	eb = path->nodes[0];
	ptr = btrfs_item_ptr_offset(eb, path->slots[0]);
	end = ptr + btrfs_item_size_nr(eb, path->slots[0]);
#ifdef BTRFS_COMPAT_EXTENT_TREE_V0
	if (ptr + sizeof(struct btrfs_extent_item_v0) == end)
		ptr = end;
	else
#endif
		ptr += sizeof(struct btrfs_extent_item);

	while (ptr < end) {
		iref = (struct btrfs_extent_inline_ref *)ptr;
		key.type = btrfs_extent_inline_ref_type(eb, iref);
		if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
			key.offset = btrfs_extent_inline_ref_offset(eb, iref);
			ret = __add_tree_block(rc, key.offset, blocksize,
					       blocks);
		} else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
			dref = (struct btrfs_extent_data_ref *)(&iref->offset);
			ret = find_data_references(rc, extent_key,
						   eb, dref, blocks);
		} else {
			BUG();
		}
3683 3684 3685 3686
		if (ret) {
			err = ret;
			goto out;
		}
3687 3688 3689 3690 3691 3692 3693 3694 3695 3696 3697 3698 3699 3700 3701 3702 3703 3704 3705 3706 3707 3708 3709 3710 3711 3712 3713 3714 3715 3716 3717 3718 3719 3720 3721 3722 3723 3724 3725 3726 3727 3728 3729 3730 3731
		ptr += btrfs_extent_inline_ref_size(key.type);
	}
	WARN_ON(ptr > end);

	while (1) {
		cond_resched();
		eb = path->nodes[0];
		if (path->slots[0] >= btrfs_header_nritems(eb)) {
			ret = btrfs_next_leaf(rc->extent_root, path);
			if (ret < 0) {
				err = ret;
				break;
			}
			if (ret > 0)
				break;
			eb = path->nodes[0];
		}

		btrfs_item_key_to_cpu(eb, &key, path->slots[0]);
		if (key.objectid != extent_key->objectid)
			break;

#ifdef BTRFS_COMPAT_EXTENT_TREE_V0
		if (key.type == BTRFS_SHARED_DATA_REF_KEY ||
		    key.type == BTRFS_EXTENT_REF_V0_KEY) {
#else
		BUG_ON(key.type == BTRFS_EXTENT_REF_V0_KEY);
		if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
#endif
			ret = __add_tree_block(rc, key.offset, blocksize,
					       blocks);
		} else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
			dref = btrfs_item_ptr(eb, path->slots[0],
					      struct btrfs_extent_data_ref);
			ret = find_data_references(rc, extent_key,
						   eb, dref, blocks);
		} else {
			ret = 0;
		}
		if (ret) {
			err = ret;
			break;
		}
		path->slots[0]++;
	}
3732
out:
3733
	btrfs_release_path(path);
3734 3735 3736 3737 3738 3739
	if (err)
		free_block_list(blocks);
	return err;
}

/*
L
Liu Bo 已提交
3740
 * helper to find next unprocessed extent
3741 3742 3743
 */
static noinline_for_stack
int find_next_extent(struct btrfs_trans_handle *trans,
3744 3745
		     struct reloc_control *rc, struct btrfs_path *path,
		     struct btrfs_key *extent_key)
3746 3747 3748 3749 3750 3751 3752 3753 3754 3755 3756 3757 3758 3759 3760 3761 3762 3763 3764 3765 3766 3767 3768 3769 3770 3771 3772 3773 3774 3775 3776 3777 3778 3779 3780 3781 3782 3783 3784
{
	struct btrfs_key key;
	struct extent_buffer *leaf;
	u64 start, end, last;
	int ret;

	last = rc->block_group->key.objectid + rc->block_group->key.offset;
	while (1) {
		cond_resched();
		if (rc->search_start >= last) {
			ret = 1;
			break;
		}

		key.objectid = rc->search_start;
		key.type = BTRFS_EXTENT_ITEM_KEY;
		key.offset = 0;

		path->search_commit_root = 1;
		path->skip_locking = 1;
		ret = btrfs_search_slot(NULL, rc->extent_root, &key, path,
					0, 0);
		if (ret < 0)
			break;
next:
		leaf = path->nodes[0];
		if (path->slots[0] >= btrfs_header_nritems(leaf)) {
			ret = btrfs_next_leaf(rc->extent_root, path);
			if (ret != 0)
				break;
			leaf = path->nodes[0];
		}

		btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
		if (key.objectid >= last) {
			ret = 1;
			break;
		}

3785 3786 3787 3788 3789 3790 3791
		if (key.type != BTRFS_EXTENT_ITEM_KEY &&
		    key.type != BTRFS_METADATA_ITEM_KEY) {
			path->slots[0]++;
			goto next;
		}

		if (key.type == BTRFS_EXTENT_ITEM_KEY &&
3792 3793 3794 3795 3796
		    key.objectid + key.offset <= rc->search_start) {
			path->slots[0]++;
			goto next;
		}

3797 3798 3799 3800 3801 3802 3803
		if (key.type == BTRFS_METADATA_ITEM_KEY &&
		    key.objectid + rc->extent_root->leafsize <=
		    rc->search_start) {
			path->slots[0]++;
			goto next;
		}

3804 3805
		ret = find_first_extent_bit(&rc->processed_blocks,
					    key.objectid, &start, &end,
3806
					    EXTENT_DIRTY, NULL);
3807 3808

		if (ret == 0 && start <= key.objectid) {
3809
			btrfs_release_path(path);
3810 3811
			rc->search_start = end + 1;
		} else {
3812 3813 3814 3815 3816
			if (key.type == BTRFS_EXTENT_ITEM_KEY)
				rc->search_start = key.objectid + key.offset;
			else
				rc->search_start = key.objectid +
					rc->extent_root->leafsize;
3817
			memcpy(extent_key, &key, sizeof(key));
3818 3819 3820
			return 0;
		}
	}
3821
	btrfs_release_path(path);
3822 3823 3824 3825 3826 3827
	return ret;
}

static void set_reloc_control(struct reloc_control *rc)
{
	struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
C
Chris Mason 已提交
3828 3829

	mutex_lock(&fs_info->reloc_mutex);
3830
	fs_info->reloc_ctl = rc;
C
Chris Mason 已提交
3831
	mutex_unlock(&fs_info->reloc_mutex);
3832 3833 3834 3835 3836
}

static void unset_reloc_control(struct reloc_control *rc)
{
	struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
C
Chris Mason 已提交
3837 3838

	mutex_lock(&fs_info->reloc_mutex);
3839
	fs_info->reloc_ctl = NULL;
C
Chris Mason 已提交
3840
	mutex_unlock(&fs_info->reloc_mutex);
3841 3842 3843 3844 3845 3846 3847 3848 3849 3850 3851 3852 3853 3854 3855 3856
}

static int check_extent_flags(u64 flags)
{
	if ((flags & BTRFS_EXTENT_FLAG_DATA) &&
	    (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK))
		return 1;
	if (!(flags & BTRFS_EXTENT_FLAG_DATA) &&
	    !(flags & BTRFS_EXTENT_FLAG_TREE_BLOCK))
		return 1;
	if ((flags & BTRFS_EXTENT_FLAG_DATA) &&
	    (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
		return 1;
	return 0;
}

3857 3858 3859 3860 3861 3862
static noinline_for_stack
int prepare_to_relocate(struct reloc_control *rc)
{
	struct btrfs_trans_handle *trans;
	int ret;

3863 3864
	rc->block_rsv = btrfs_alloc_block_rsv(rc->extent_root,
					      BTRFS_BLOCK_RSV_TEMP);
3865 3866 3867 3868 3869 3870 3871 3872
	if (!rc->block_rsv)
		return -ENOMEM;

	/*
	 * reserve some space for creating reloc trees.
	 * btrfs_init_reloc_root will use them when there
	 * is no reservation in transaction handle.
	 */
3873
	ret = btrfs_block_rsv_add(rc->extent_root, rc->block_rsv,
M
Miao Xie 已提交
3874 3875
				  rc->extent_root->nodesize * 256,
				  BTRFS_RESERVE_FLUSH_ALL);
3876 3877 3878 3879 3880 3881 3882 3883 3884 3885 3886 3887
	if (ret)
		return ret;

	memset(&rc->cluster, 0, sizeof(rc->cluster));
	rc->search_start = rc->block_group->key.objectid;
	rc->extents_found = 0;
	rc->nodes_relocated = 0;
	rc->merging_rsv_size = 0;

	rc->create_reloc_tree = 1;
	set_reloc_control(rc);

3888
	trans = btrfs_join_transaction(rc->extent_root);
3889 3890 3891 3892 3893 3894 3895 3896 3897
	if (IS_ERR(trans)) {
		unset_reloc_control(rc);
		/*
		 * extent tree is not a ref_cow tree and has no reloc_root to
		 * cleanup.  And callers are responsible to free the above
		 * block rsv.
		 */
		return PTR_ERR(trans);
	}
3898 3899 3900
	btrfs_commit_transaction(trans, rc->extent_root);
	return 0;
}
3901

3902 3903 3904 3905 3906 3907 3908 3909 3910 3911 3912
static noinline_for_stack int relocate_block_group(struct reloc_control *rc)
{
	struct rb_root blocks = RB_ROOT;
	struct btrfs_key key;
	struct btrfs_trans_handle *trans = NULL;
	struct btrfs_path *path;
	struct btrfs_extent_item *ei;
	u64 flags;
	u32 item_size;
	int ret;
	int err = 0;
3913
	int progress = 0;
3914 3915

	path = btrfs_alloc_path();
3916
	if (!path)
3917
		return -ENOMEM;
J
Josef Bacik 已提交
3918
	path->reada = 1;
3919

3920 3921 3922 3923 3924
	ret = prepare_to_relocate(rc);
	if (ret) {
		err = ret;
		goto out_free;
	}
3925 3926

	while (1) {
3927
		progress++;
3928
		trans = btrfs_start_transaction(rc->extent_root, 0);
3929 3930 3931 3932 3933
		if (IS_ERR(trans)) {
			err = PTR_ERR(trans);
			trans = NULL;
			break;
		}
3934
restart:
3935 3936 3937 3938 3939 3940
		if (update_backref_cache(trans, &rc->backref_cache)) {
			btrfs_end_transaction(trans, rc->extent_root);
			continue;
		}

		ret = find_next_extent(trans, rc, path, &key);
3941 3942 3943 3944 3945 3946 3947 3948 3949
		if (ret < 0)
			err = ret;
		if (ret != 0)
			break;

		rc->extents_found++;

		ei = btrfs_item_ptr(path->nodes[0], path->slots[0],
				    struct btrfs_extent_item);
3950
		item_size = btrfs_item_size_nr(path->nodes[0], path->slots[0]);
3951 3952 3953 3954 3955 3956 3957 3958 3959 3960 3961 3962 3963 3964 3965 3966 3967 3968 3969 3970
		if (item_size >= sizeof(*ei)) {
			flags = btrfs_extent_flags(path->nodes[0], ei);
			ret = check_extent_flags(flags);
			BUG_ON(ret);

		} else {
#ifdef BTRFS_COMPAT_EXTENT_TREE_V0
			u64 ref_owner;
			int path_change = 0;

			BUG_ON(item_size !=
			       sizeof(struct btrfs_extent_item_v0));
			ret = get_ref_objectid_v0(rc, path, &key, &ref_owner,
						  &path_change);
			if (ref_owner < BTRFS_FIRST_FREE_OBJECTID)
				flags = BTRFS_EXTENT_FLAG_TREE_BLOCK;
			else
				flags = BTRFS_EXTENT_FLAG_DATA;

			if (path_change) {
3971
				btrfs_release_path(path);
3972 3973 3974 3975 3976 3977 3978 3979 3980 3981 3982 3983 3984 3985 3986 3987 3988 3989 3990

				path->search_commit_root = 1;
				path->skip_locking = 1;
				ret = btrfs_search_slot(NULL, rc->extent_root,
							&key, path, 0, 0);
				if (ret < 0) {
					err = ret;
					break;
				}
				BUG_ON(ret > 0);
			}
#else
			BUG();
#endif
		}

		if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
			ret = add_tree_block(rc, &key, path, &blocks);
		} else if (rc->stage == UPDATE_DATA_PTRS &&
3991
			   (flags & BTRFS_EXTENT_FLAG_DATA)) {
3992 3993
			ret = add_data_references(rc, &key, path, &blocks);
		} else {
3994
			btrfs_release_path(path);
3995 3996 3997
			ret = 0;
		}
		if (ret < 0) {
3998
			err = ret;
3999 4000 4001 4002 4003 4004
			break;
		}

		if (!RB_EMPTY_ROOT(&blocks)) {
			ret = relocate_tree_blocks(trans, rc, &blocks);
			if (ret < 0) {
4005 4006 4007 4008 4009 4010 4011 4012 4013 4014 4015 4016 4017 4018 4019
				if (ret != -EAGAIN) {
					err = ret;
					break;
				}
				rc->extents_found--;
				rc->search_start = key.objectid;
			}
		}

		if (rc->commit_transaction) {
			rc->commit_transaction = 0;
			ret = btrfs_commit_transaction(trans, rc->extent_root);
			BUG_ON(ret);
		} else {
			btrfs_end_transaction_throttle(trans, rc->extent_root);
4020
			btrfs_btree_balance_dirty(rc->extent_root);
4021
		}
4022 4023 4024 4025 4026
		trans = NULL;

		if (rc->stage == MOVE_DATA_EXTENTS &&
		    (flags & BTRFS_EXTENT_FLAG_DATA)) {
			rc->found_file_extent = 1;
4027
			ret = relocate_data_extent(rc->data_inode,
4028
						   &key, &rc->cluster);
4029 4030 4031 4032 4033 4034
			if (ret < 0) {
				err = ret;
				break;
			}
		}
	}
4035 4036 4037 4038 4039 4040 4041 4042 4043
	if (trans && progress && err == -ENOSPC) {
		ret = btrfs_force_chunk_alloc(trans, rc->extent_root,
					      rc->block_group->flags);
		if (ret == 0) {
			err = 0;
			progress = 0;
			goto restart;
		}
	}
4044

4045
	btrfs_release_path(path);
4046 4047
	clear_extent_bits(&rc->processed_blocks, 0, (u64)-1, EXTENT_DIRTY,
			  GFP_NOFS);
4048 4049

	if (trans) {
4050
		btrfs_end_transaction_throttle(trans, rc->extent_root);
4051
		btrfs_btree_balance_dirty(rc->extent_root);
4052 4053
	}

4054
	if (!err) {
4055 4056
		ret = relocate_file_extent_cluster(rc->data_inode,
						   &rc->cluster);
4057 4058 4059 4060
		if (ret < 0)
			err = ret;
	}

4061 4062
	rc->create_reloc_tree = 0;
	set_reloc_control(rc);
4063

4064 4065
	backref_cache_cleanup(&rc->backref_cache);
	btrfs_block_rsv_release(rc->extent_root, rc->block_rsv, (u64)-1);
4066

4067
	err = prepare_to_merge(rc, err);
4068 4069 4070

	merge_reloc_roots(rc);

4071
	rc->merge_reloc_tree = 0;
4072
	unset_reloc_control(rc);
4073
	btrfs_block_rsv_release(rc->extent_root, rc->block_rsv, (u64)-1);
4074 4075

	/* get rid of pinned extents */
4076
	trans = btrfs_join_transaction(rc->extent_root);
4077 4078 4079 4080
	if (IS_ERR(trans))
		err = PTR_ERR(trans);
	else
		btrfs_commit_transaction(trans, rc->extent_root);
4081 4082 4083
out_free:
	btrfs_free_block_rsv(rc->extent_root, rc->block_rsv);
	btrfs_free_path(path);
4084 4085 4086 4087
	return err;
}

static int __insert_orphan_inode(struct btrfs_trans_handle *trans,
4088
				 struct btrfs_root *root, u64 objectid)
4089 4090 4091 4092 4093 4094 4095 4096 4097 4098 4099 4100 4101 4102 4103 4104 4105 4106
{
	struct btrfs_path *path;
	struct btrfs_inode_item *item;
	struct extent_buffer *leaf;
	int ret;

	path = btrfs_alloc_path();
	if (!path)
		return -ENOMEM;

	ret = btrfs_insert_empty_inode(trans, root, path, objectid);
	if (ret)
		goto out;

	leaf = path->nodes[0];
	item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_inode_item);
	memset_extent_buffer(leaf, 0, (unsigned long)item, sizeof(*item));
	btrfs_set_inode_generation(leaf, item, 1);
4107
	btrfs_set_inode_size(leaf, item, 0);
4108
	btrfs_set_inode_mode(leaf, item, S_IFREG | 0600);
4109 4110
	btrfs_set_inode_flags(leaf, item, BTRFS_INODE_NOCOMPRESS |
					  BTRFS_INODE_PREALLOC);
4111
	btrfs_mark_buffer_dirty(leaf);
4112
	btrfs_release_path(path);
4113 4114 4115 4116 4117 4118 4119 4120 4121
out:
	btrfs_free_path(path);
	return ret;
}

/*
 * helper to create inode for data relocation.
 * the inode is in data relocation tree and its link count is 0
 */
4122 4123 4124
static noinline_for_stack
struct inode *create_reloc_inode(struct btrfs_fs_info *fs_info,
				 struct btrfs_block_group_cache *group)
4125 4126 4127 4128 4129 4130 4131 4132 4133 4134 4135 4136
{
	struct inode *inode = NULL;
	struct btrfs_trans_handle *trans;
	struct btrfs_root *root;
	struct btrfs_key key;
	u64 objectid = BTRFS_FIRST_FREE_OBJECTID;
	int err = 0;

	root = read_fs_root(fs_info, BTRFS_DATA_RELOC_TREE_OBJECTID);
	if (IS_ERR(root))
		return ERR_CAST(root);

4137
	trans = btrfs_start_transaction(root, 6);
4138 4139
	if (IS_ERR(trans))
		return ERR_CAST(trans);
4140

4141
	err = btrfs_find_free_objectid(root, &objectid);
4142 4143 4144
	if (err)
		goto out;

4145
	err = __insert_orphan_inode(trans, root, objectid);
4146 4147 4148 4149 4150
	BUG_ON(err);

	key.objectid = objectid;
	key.type = BTRFS_INODE_ITEM_KEY;
	key.offset = 0;
4151
	inode = btrfs_iget(root->fs_info->sb, &key, root, NULL);
4152 4153 4154 4155 4156 4157
	BUG_ON(IS_ERR(inode) || is_bad_inode(inode));
	BTRFS_I(inode)->index_cnt = group->key.objectid;

	err = btrfs_orphan_add(trans, inode);
out:
	btrfs_end_transaction(trans, root);
4158
	btrfs_btree_balance_dirty(root);
4159 4160 4161 4162 4163 4164 4165 4166
	if (err) {
		if (inode)
			iput(inode);
		inode = ERR_PTR(err);
	}
	return inode;
}

4167
static struct reloc_control *alloc_reloc_control(struct btrfs_fs_info *fs_info)
4168 4169 4170 4171 4172 4173 4174 4175 4176 4177
{
	struct reloc_control *rc;

	rc = kzalloc(sizeof(*rc), GFP_NOFS);
	if (!rc)
		return NULL;

	INIT_LIST_HEAD(&rc->reloc_roots);
	backref_cache_init(&rc->backref_cache);
	mapping_tree_init(&rc->reloc_root_tree);
4178 4179
	extent_io_tree_init(&rc->processed_blocks,
			    fs_info->btree_inode->i_mapping);
4180 4181 4182
	return rc;
}

4183 4184 4185 4186 4187 4188 4189
/*
 * function to relocate all extents in a block group.
 */
int btrfs_relocate_block_group(struct btrfs_root *extent_root, u64 group_start)
{
	struct btrfs_fs_info *fs_info = extent_root->fs_info;
	struct reloc_control *rc;
4190 4191
	struct inode *inode;
	struct btrfs_path *path;
4192
	int ret;
4193
	int rw = 0;
4194 4195
	int err = 0;

4196
	rc = alloc_reloc_control(fs_info);
4197 4198 4199
	if (!rc)
		return -ENOMEM;

4200
	rc->extent_root = extent_root;
4201

4202 4203 4204
	rc->block_group = btrfs_lookup_block_group(fs_info, group_start);
	BUG_ON(!rc->block_group);

4205 4206 4207 4208 4209 4210 4211 4212 4213
	if (!rc->block_group->ro) {
		ret = btrfs_set_block_group_ro(extent_root, rc->block_group);
		if (ret) {
			err = ret;
			goto out;
		}
		rw = 1;
	}

4214 4215 4216 4217 4218 4219 4220 4221 4222 4223 4224 4225 4226 4227 4228 4229 4230 4231 4232 4233
	path = btrfs_alloc_path();
	if (!path) {
		err = -ENOMEM;
		goto out;
	}

	inode = lookup_free_space_inode(fs_info->tree_root, rc->block_group,
					path);
	btrfs_free_path(path);

	if (!IS_ERR(inode))
		ret = delete_block_group_cache(fs_info, inode, 0);
	else
		ret = PTR_ERR(inode);

	if (ret && ret != -ENOENT) {
		err = ret;
		goto out;
	}

4234 4235 4236 4237 4238 4239 4240 4241
	rc->data_inode = create_reloc_inode(fs_info, rc->block_group);
	if (IS_ERR(rc->data_inode)) {
		err = PTR_ERR(rc->data_inode);
		rc->data_inode = NULL;
		goto out;
	}

	printk(KERN_INFO "btrfs: relocating block group %llu flags %llu\n",
4242
	       rc->block_group->key.objectid, rc->block_group->flags);
4243

4244
	ret = btrfs_start_delalloc_roots(fs_info, 0);
4245 4246 4247 4248
	if (ret < 0) {
		err = ret;
		goto out;
	}
4249
	btrfs_wait_ordered_roots(fs_info, -1);
4250 4251

	while (1) {
4252
		mutex_lock(&fs_info->cleaner_mutex);
4253
		ret = relocate_block_group(rc);
4254
		mutex_unlock(&fs_info->cleaner_mutex);
4255 4256
		if (ret < 0) {
			err = ret;
4257
			goto out;
4258 4259 4260 4261 4262 4263
		}

		if (rc->extents_found == 0)
			break;

		printk(KERN_INFO "btrfs: found %llu extents\n",
4264
			rc->extents_found);
4265 4266

		if (rc->stage == MOVE_DATA_EXTENTS && rc->found_file_extent) {
4267 4268 4269 4270 4271 4272
			ret = btrfs_wait_ordered_range(rc->data_inode, 0,
						       (u64)-1);
			if (ret) {
				err = ret;
				goto out;
			}
4273 4274 4275 4276 4277 4278
			invalidate_mapping_pages(rc->data_inode->i_mapping,
						 0, -1);
			rc->stage = UPDATE_DATA_PTRS;
		}
	}

4279 4280 4281 4282
	filemap_write_and_wait_range(fs_info->btree_inode->i_mapping,
				     rc->block_group->key.objectid,
				     rc->block_group->key.objectid +
				     rc->block_group->key.offset - 1);
4283 4284 4285 4286 4287

	WARN_ON(rc->block_group->pinned > 0);
	WARN_ON(rc->block_group->reserved > 0);
	WARN_ON(btrfs_block_group_used(&rc->block_group->item) > 0);
out:
4288 4289
	if (err && rw)
		btrfs_set_block_group_rw(extent_root, rc->block_group);
4290 4291 4292 4293 4294 4295
	iput(rc->data_inode);
	btrfs_put_block_group(rc->block_group);
	kfree(rc);
	return err;
}

4296 4297 4298
static noinline_for_stack int mark_garbage_root(struct btrfs_root *root)
{
	struct btrfs_trans_handle *trans;
4299
	int ret, err;
4300

4301
	trans = btrfs_start_transaction(root->fs_info->tree_root, 0);
4302 4303
	if (IS_ERR(trans))
		return PTR_ERR(trans);
4304 4305 4306 4307 4308 4309 4310 4311

	memset(&root->root_item.drop_progress, 0,
		sizeof(root->root_item.drop_progress));
	root->root_item.drop_level = 0;
	btrfs_set_root_refs(&root->root_item, 0);
	ret = btrfs_update_root(trans, root->fs_info->tree_root,
				&root->root_key, &root->root_item);

4312 4313 4314 4315
	err = btrfs_end_transaction(trans, root->fs_info->tree_root);
	if (err)
		return err;
	return ret;
4316 4317
}

4318 4319 4320 4321 4322 4323 4324 4325 4326 4327 4328 4329 4330 4331 4332 4333 4334 4335 4336 4337 4338 4339
/*
 * recover relocation interrupted by system crash.
 *
 * this function resumes merging reloc trees with corresponding fs trees.
 * this is important for keeping the sharing of tree blocks
 */
int btrfs_recover_relocation(struct btrfs_root *root)
{
	LIST_HEAD(reloc_roots);
	struct btrfs_key key;
	struct btrfs_root *fs_root;
	struct btrfs_root *reloc_root;
	struct btrfs_path *path;
	struct extent_buffer *leaf;
	struct reloc_control *rc = NULL;
	struct btrfs_trans_handle *trans;
	int ret;
	int err = 0;

	path = btrfs_alloc_path();
	if (!path)
		return -ENOMEM;
J
Josef Bacik 已提交
4340
	path->reada = -1;
4341 4342 4343 4344 4345 4346 4347 4348 4349 4350 4351 4352 4353 4354 4355 4356 4357 4358 4359

	key.objectid = BTRFS_TREE_RELOC_OBJECTID;
	key.type = BTRFS_ROOT_ITEM_KEY;
	key.offset = (u64)-1;

	while (1) {
		ret = btrfs_search_slot(NULL, root->fs_info->tree_root, &key,
					path, 0, 0);
		if (ret < 0) {
			err = ret;
			goto out;
		}
		if (ret > 0) {
			if (path->slots[0] == 0)
				break;
			path->slots[0]--;
		}
		leaf = path->nodes[0];
		btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
4360
		btrfs_release_path(path);
4361 4362 4363 4364 4365

		if (key.objectid != BTRFS_TREE_RELOC_OBJECTID ||
		    key.type != BTRFS_ROOT_ITEM_KEY)
			break;

4366
		reloc_root = btrfs_read_fs_root(root, &key);
4367 4368 4369 4370 4371 4372 4373 4374 4375 4376 4377
		if (IS_ERR(reloc_root)) {
			err = PTR_ERR(reloc_root);
			goto out;
		}

		list_add(&reloc_root->root_list, &reloc_roots);

		if (btrfs_root_refs(&reloc_root->root_item) > 0) {
			fs_root = read_fs_root(root->fs_info,
					       reloc_root->root_key.offset);
			if (IS_ERR(fs_root)) {
4378 4379 4380 4381 4382
				ret = PTR_ERR(fs_root);
				if (ret != -ENOENT) {
					err = ret;
					goto out;
				}
4383 4384 4385 4386 4387
				ret = mark_garbage_root(reloc_root);
				if (ret < 0) {
					err = ret;
					goto out;
				}
4388 4389 4390 4391 4392 4393 4394 4395
			}
		}

		if (key.offset == 0)
			break;

		key.offset--;
	}
4396
	btrfs_release_path(path);
4397 4398 4399 4400

	if (list_empty(&reloc_roots))
		goto out;

4401
	rc = alloc_reloc_control(root->fs_info);
4402 4403 4404 4405 4406 4407 4408 4409 4410
	if (!rc) {
		err = -ENOMEM;
		goto out;
	}

	rc->extent_root = root->fs_info->extent_root;

	set_reloc_control(rc);

4411
	trans = btrfs_join_transaction(rc->extent_root);
4412 4413 4414 4415 4416
	if (IS_ERR(trans)) {
		unset_reloc_control(rc);
		err = PTR_ERR(trans);
		goto out_free;
	}
4417 4418 4419

	rc->merge_reloc_tree = 1;

4420 4421 4422 4423 4424 4425 4426 4427 4428 4429 4430 4431 4432
	while (!list_empty(&reloc_roots)) {
		reloc_root = list_entry(reloc_roots.next,
					struct btrfs_root, root_list);
		list_del(&reloc_root->root_list);

		if (btrfs_root_refs(&reloc_root->root_item) == 0) {
			list_add_tail(&reloc_root->root_list,
				      &rc->reloc_roots);
			continue;
		}

		fs_root = read_fs_root(root->fs_info,
				       reloc_root->root_key.offset);
4433 4434 4435 4436
		if (IS_ERR(fs_root)) {
			err = PTR_ERR(fs_root);
			goto out_free;
		}
4437

4438
		err = __add_reloc_root(reloc_root);
4439
		BUG_ON(err < 0); /* -ENOMEM or logic error */
4440 4441 4442
		fs_root->reloc_root = reloc_root;
	}

4443 4444 4445
	err = btrfs_commit_transaction(trans, rc->extent_root);
	if (err)
		goto out_free;
4446 4447 4448 4449 4450

	merge_reloc_roots(rc);

	unset_reloc_control(rc);

4451
	trans = btrfs_join_transaction(rc->extent_root);
4452 4453 4454
	if (IS_ERR(trans))
		err = PTR_ERR(trans);
	else
4455
		err = btrfs_commit_transaction(trans, rc->extent_root);
4456
out_free:
4457
	kfree(rc);
4458
out:
4459 4460 4461
	if (!list_empty(&reloc_roots))
		free_reloc_roots(&reloc_roots);

4462 4463 4464 4465 4466 4467 4468 4469
	btrfs_free_path(path);

	if (err == 0) {
		/* cleanup orphan inode in data relocation tree */
		fs_root = read_fs_root(root->fs_info,
				       BTRFS_DATA_RELOC_TREE_OBJECTID);
		if (IS_ERR(fs_root))
			err = PTR_ERR(fs_root);
4470
		else
4471
			err = btrfs_orphan_cleanup(fs_root);
4472 4473 4474 4475 4476 4477 4478 4479 4480 4481 4482 4483 4484 4485 4486 4487 4488
	}
	return err;
}

/*
 * helper to add ordered checksum for data relocation.
 *
 * cloning checksum properly handles the nodatasum extents.
 * it also saves CPU time to re-calculate the checksum.
 */
int btrfs_reloc_clone_csums(struct inode *inode, u64 file_pos, u64 len)
{
	struct btrfs_ordered_sum *sums;
	struct btrfs_ordered_extent *ordered;
	struct btrfs_root *root = BTRFS_I(inode)->root;
	int ret;
	u64 disk_bytenr;
4489
	u64 new_bytenr;
4490 4491 4492 4493 4494 4495 4496
	LIST_HEAD(list);

	ordered = btrfs_lookup_ordered_extent(inode, file_pos);
	BUG_ON(ordered->file_offset != file_pos || ordered->len != len);

	disk_bytenr = file_pos + BTRFS_I(inode)->index_cnt;
	ret = btrfs_lookup_csums_range(root->fs_info->csum_root, disk_bytenr,
A
Arne Jansen 已提交
4497
				       disk_bytenr + len - 1, &list, 0);
4498 4499
	if (ret)
		goto out;
4500 4501 4502 4503 4504

	while (!list_empty(&list)) {
		sums = list_entry(list.next, struct btrfs_ordered_sum, list);
		list_del_init(&sums->list);

4505 4506 4507 4508 4509 4510 4511 4512 4513 4514 4515 4516 4517 4518
		/*
		 * We need to offset the new_bytenr based on where the csum is.
		 * We need to do this because we will read in entire prealloc
		 * extents but we may have written to say the middle of the
		 * prealloc extent, so we need to make sure the csum goes with
		 * the right disk offset.
		 *
		 * We can do this because the data reloc inode refers strictly
		 * to the on disk bytes, so we don't have to worry about
		 * disk_len vs real len like with real inodes since it's all
		 * disk length.
		 */
		new_bytenr = ordered->start + (sums->bytenr - disk_bytenr);
		sums->bytenr = new_bytenr;
4519 4520 4521

		btrfs_add_ordered_sum(inode, ordered, sums);
	}
4522
out:
4523
	btrfs_put_ordered_extent(ordered);
4524
	return ret;
4525
}
4526

4527 4528 4529
int btrfs_reloc_cow_block(struct btrfs_trans_handle *trans,
			  struct btrfs_root *root, struct extent_buffer *buf,
			  struct extent_buffer *cow)
4530 4531 4532 4533 4534
{
	struct reloc_control *rc;
	struct backref_node *node;
	int first_cow = 0;
	int level;
4535
	int ret = 0;
4536 4537 4538

	rc = root->fs_info->reloc_ctl;
	if (!rc)
4539
		return 0;
4540 4541 4542 4543

	BUG_ON(rc->stage == UPDATE_DATA_PTRS &&
	       root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID);

4544 4545 4546 4547 4548
	if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) {
		if (buf == root->node)
			__update_reloc_root(root, cow->start);
	}

4549 4550 4551 4552 4553 4554 4555 4556 4557 4558 4559 4560 4561 4562 4563 4564 4565 4566 4567 4568 4569 4570 4571 4572 4573 4574 4575 4576 4577 4578 4579
	level = btrfs_header_level(buf);
	if (btrfs_header_generation(buf) <=
	    btrfs_root_last_snapshot(&root->root_item))
		first_cow = 1;

	if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID &&
	    rc->create_reloc_tree) {
		WARN_ON(!first_cow && level == 0);

		node = rc->backref_cache.path[level];
		BUG_ON(node->bytenr != buf->start &&
		       node->new_bytenr != buf->start);

		drop_node_buffer(node);
		extent_buffer_get(cow);
		node->eb = cow;
		node->new_bytenr = cow->start;

		if (!node->pending) {
			list_move_tail(&node->list,
				       &rc->backref_cache.pending[level]);
			node->pending = 1;
		}

		if (first_cow)
			__mark_block_processed(rc, node);

		if (first_cow && level > 0)
			rc->nodes_relocated += buf->len;
	}

4580
	if (level == 0 && first_cow && rc->stage == UPDATE_DATA_PTRS)
4581
		ret = replace_file_extents(trans, rc, root, cow);
4582
	return ret;
4583 4584 4585 4586 4587 4588 4589 4590 4591 4592 4593 4594 4595 4596 4597 4598 4599 4600 4601 4602 4603 4604 4605 4606 4607 4608 4609 4610 4611 4612 4613 4614 4615 4616 4617 4618 4619 4620 4621 4622
}

/*
 * called before creating snapshot. it calculates metadata reservation
 * requried for relocating tree blocks in the snapshot
 */
void btrfs_reloc_pre_snapshot(struct btrfs_trans_handle *trans,
			      struct btrfs_pending_snapshot *pending,
			      u64 *bytes_to_reserve)
{
	struct btrfs_root *root;
	struct reloc_control *rc;

	root = pending->root;
	if (!root->reloc_root)
		return;

	rc = root->fs_info->reloc_ctl;
	if (!rc->merge_reloc_tree)
		return;

	root = root->reloc_root;
	BUG_ON(btrfs_root_refs(&root->root_item) == 0);
	/*
	 * relocation is in the stage of merging trees. the space
	 * used by merging a reloc tree is twice the size of
	 * relocated tree nodes in the worst case. half for cowing
	 * the reloc tree, half for cowing the fs tree. the space
	 * used by cowing the reloc tree will be freed after the
	 * tree is dropped. if we create snapshot, cowing the fs
	 * tree may use more space than it frees. so we need
	 * reserve extra space.
	 */
	*bytes_to_reserve += rc->nodes_relocated;
}

/*
 * called after snapshot is created. migrate block reservation
 * and create reloc root for the newly created snapshot
 */
4623
int btrfs_reloc_post_snapshot(struct btrfs_trans_handle *trans,
4624 4625 4626 4627 4628 4629 4630 4631 4632
			       struct btrfs_pending_snapshot *pending)
{
	struct btrfs_root *root = pending->root;
	struct btrfs_root *reloc_root;
	struct btrfs_root *new_root;
	struct reloc_control *rc;
	int ret;

	if (!root->reloc_root)
4633
		return 0;
4634 4635 4636 4637 4638 4639 4640 4641

	rc = root->fs_info->reloc_ctl;
	rc->merging_rsv_size += rc->nodes_relocated;

	if (rc->merge_reloc_tree) {
		ret = btrfs_block_rsv_migrate(&pending->block_rsv,
					      rc->block_rsv,
					      rc->nodes_relocated);
4642 4643
		if (ret)
			return ret;
4644 4645 4646 4647 4648
	}

	new_root = pending->snap;
	reloc_root = create_reloc_root(trans, root->reloc_root,
				       new_root->root_key.objectid);
4649 4650
	if (IS_ERR(reloc_root))
		return PTR_ERR(reloc_root);
4651

4652 4653
	ret = __add_reloc_root(reloc_root);
	BUG_ON(ret < 0);
4654 4655
	new_root->reloc_root = reloc_root;

4656
	if (rc->create_reloc_tree)
4657
		ret = clone_backref_node(trans, rc, root, reloc_root);
4658
	return ret;
4659
}