relocation.c 103.0 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;
}

/*
 * 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);
	BUG_ON(rb_node);
}

/*
 * 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;

	return btrfs_read_fs_root_no_name(fs_info, &key);
}

#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)
{
	struct btrfs_extent_item *ei;
	struct btrfs_tree_block_info *bi;
	u32 item_size;

	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));

	if (item_size <= sizeof(*ei) + sizeof(*bi)) {
		WARN_ON(item_size < sizeof(*ei) + sizeof(*bi));
		return 1;
	}

	bi = (struct btrfs_tree_block_info *)(ei + 1);
	*ptr = (unsigned long)(bi + 1);
	*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;

	path1 = btrfs_alloc_path();
	path2 = btrfs_alloc_path();
	if (!path1 || !path2) {
		err = -ENOMEM;
		goto out;
	}
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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;
	key.type = BTRFS_EXTENT_ITEM_KEY;
	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)) {
		/*
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		 * the backref was added previously when processing
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		 * 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;
			}

			if (key.type == BTRFS_EXTENT_ITEM_KEY) {
				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) {
785
			if (key.type == BTRFS_EXTENT_REF_V0_KEY) {
786 787 788
				struct btrfs_extent_ref_v0 *ref0;
				ref0 = btrfs_item_ptr(eb, path1->slots[0],
						struct btrfs_extent_ref_v0);
789
				if (key.objectid == key.offset) {
790
					root = find_tree_root(rc, eb, ref0);
791 792 793 794 795 796
					if (root && !should_ignore_root(root))
						cur->root = root;
					else
						list_add(&cur->list, &useless);
					break;
				}
797 798 799
				if (is_cowonly_root(btrfs_ref_root_v0(eb,
								      ref0)))
					cur->cowonly = 1;
800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815
			}
#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;
			}

816
			edge = alloc_backref_edge(cache);
817 818 819 820 821 822
			if (!edge) {
				err = -ENOMEM;
				goto out;
			}
			rb_node = tree_search(&cache->rb_root, key.offset);
			if (!rb_node) {
823
				upper = alloc_backref_node(cache);
824
				if (!upper) {
825
					free_backref_edge(cache, edge);
826 827 828 829 830 831 832 833 834 835 836 837 838
					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);
839
				BUG_ON(!upper->checked);
840 841
				INIT_LIST_HEAD(&edge->list[UPPER]);
			}
842
			list_add_tail(&edge->list[LOWER], &cur->upper);
843
			edge->node[LOWER] = cur;
844
			edge->node[UPPER] = upper;
845 846 847 848 849 850 851 852 853 854 855 856 857

			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;
		}

858 859 860
		if (!root->ref_cows)
			cur->cowonly = 1;

861 862 863 864
		if (btrfs_root_level(&root->root_item) == cur->level) {
			/* tree root */
			BUG_ON(btrfs_root_bytenr(&root->root_item) !=
			       cur->bytenr);
865 866 867 868
			if (should_ignore_root(root))
				list_add(&cur->list, &useless);
			else
				cur->root = root;
869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886
			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;
		}
887 888
		if (ret > 0 && path2->slots[level] > 0)
			path2->slots[level]--;
889 890 891 892 893 894 895 896 897 898

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

		lower = cur;
		for (; level < BTRFS_MAX_LEVEL; level++) {
			if (!path2->nodes[level]) {
				BUG_ON(btrfs_root_bytenr(&root->root_item) !=
				       lower->bytenr);
899 900 901 902
				if (should_ignore_root(root))
					list_add(&lower->list, &useless);
				else
					lower->root = root;
903 904 905
				break;
			}

906
			edge = alloc_backref_edge(cache);
907 908 909 910 911 912 913 914
			if (!edge) {
				err = -ENOMEM;
				goto out;
			}

			eb = path2->nodes[level];
			rb_node = tree_search(&cache->rb_root, eb->start);
			if (!rb_node) {
915
				upper = alloc_backref_node(cache);
916
				if (!upper) {
917
					free_backref_edge(cache, edge);
918 919 920 921 922 923
					err = -ENOMEM;
					goto out;
				}
				upper->bytenr = eb->start;
				upper->owner = btrfs_header_owner(eb);
				upper->level = lower->level + 1;
924 925
				if (!root->ref_cows)
					upper->cowonly = 1;
926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954

				/*
				 * 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
				 * need check its backrefs. only block
				 * at 'cur->level + 1' is added to the
				 * tail of pending list. this guarantees
				 * we check backrefs from lower level
				 * blocks to upper level blocks.
				 */
				if (!upper->checked &&
				    level == cur->level + 1) {
					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]);
955 956
				if (!upper->owner)
					upper->owner = btrfs_header_owner(eb);
957 958 959
			}
			list_add_tail(&edge->list[LOWER], &lower->upper);
			edge->node[LOWER] = lower;
960
			edge->node[UPPER] = upper;
961 962 963 964 965 966

			if (rb_node)
				break;
			lower = upper;
			upper = NULL;
		}
967
		btrfs_release_path(path2);
968 969 970 971 972 973 974 975 976 977 978 979
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]++;
	}
980
	btrfs_release_path(path1);
981 982 983 984 985 986 987 988 989 990 991 992 993 994 995 996 997

	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);
998 999 1000 1001 1002 1003 1004
	cowonly = node->cowonly;
	if (!cowonly) {
		rb_node = tree_insert(&cache->rb_root, node->bytenr,
				      &node->rb_node);
		BUG_ON(rb_node);
		list_add_tail(&node->lower, &cache->leaves);
	}
1005 1006 1007 1008 1009 1010 1011 1012

	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];
1013 1014 1015 1016 1017 1018 1019 1020
		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;
		}
1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032

		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);
1033 1034 1035 1036 1037 1038
		BUG_ON(cowonly != upper->cowonly);
		if (!cowonly) {
			rb_node = tree_insert(&cache->rb_root, upper->bytenr,
					      &upper->rb_node);
			BUG_ON(rb_node);
		}
1039 1040 1041 1042 1043 1044

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

		list_for_each_entry(edge, &upper->upper, list[LOWER])
			list_add_tail(&edge->list[UPPER], &list);
	}
1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080
	/*
	 * 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);
		}
	}
1081 1082 1083 1084
out:
	btrfs_free_path(path1);
	btrfs_free_path(path2);
	if (err) {
1085 1086 1087 1088 1089
		while (!list_empty(&useless)) {
			lower = list_entry(useless.next,
					   struct backref_node, upper);
			list_del_init(&lower->upper);
		}
1090
		upper = node;
1091
		INIT_LIST_HEAD(&list);
1092 1093 1094
		while (upper) {
			if (RB_EMPTY_NODE(&upper->rb_node)) {
				list_splice_tail(&upper->upper, &list);
1095
				free_backref_node(cache, upper);
1096 1097 1098 1099 1100 1101 1102
			}

			if (list_empty(&list))
				break;

			edge = list_entry(list.next, struct backref_edge,
					  list[LOWER]);
1103
			list_del(&edge->list[LOWER]);
1104
			upper = edge->node[UPPER];
1105
			free_backref_edge(cache, edge);
1106 1107 1108
		}
		return ERR_PTR(err);
	}
1109
	BUG_ON(node && node->detached);
1110 1111 1112
	return node;
}

1113 1114 1115 1116 1117 1118 1119 1120 1121 1122 1123 1124 1125 1126 1127 1128 1129 1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155 1156 1157 1158 1159 1160 1161 1162
/*
 * 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
1163
	new_node->checked = 1;
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 1193 1194 1195 1196 1197 1198 1199 1200
	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);
		}
	}

	rb_node = tree_insert(&cache->rb_root, new_node->bytenr,
			      &new_node->rb_node);
	BUG_ON(rb_node);

	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;
}

1201 1202 1203 1204 1205 1206 1207 1208 1209 1210 1211 1212 1213 1214 1215 1216 1217 1218 1219 1220 1221 1222 1223 1224 1225 1226 1227 1228 1229 1230 1231 1232 1233 1234 1235 1236 1237 1238 1239 1240 1241 1242 1243 1244 1245 1246 1247 1248 1249 1250 1251 1252 1253 1254 1255 1256 1257 1258 1259 1260
/*
 * helper to add 'address of tree root -> reloc tree' mapping
 */
static int __add_reloc_root(struct btrfs_root *root)
{
	struct rb_node *rb_node;
	struct mapping_node *node;
	struct reloc_control *rc = root->fs_info->reloc_ctl;

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

	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);
	BUG_ON(rb_node);

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

/*
 * helper to update/delete the 'address of tree root -> reloc tree'
 * mapping
 */
static int __update_reloc_root(struct btrfs_root *root, int del)
{
	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->commit_root->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);
	}
	spin_unlock(&rc->reloc_root_tree.lock);

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

	if (!del) {
		spin_lock(&rc->reloc_root_tree.lock);
		node->bytenr = root->node->start;
		rb_node = tree_insert(&rc->reloc_root_tree.rb_root,
				      node->bytenr, &node->rb_node);
		spin_unlock(&rc->reloc_root_tree.lock);
		BUG_ON(rb_node);
	} else {
		list_del_init(&root->root_list);
		kfree(node);
	}
	return 0;
}

1261 1262
static struct btrfs_root *create_reloc_root(struct btrfs_trans_handle *trans,
					struct btrfs_root *root, u64 objectid)
1263 1264 1265 1266 1267 1268 1269 1270 1271 1272 1273 1274
{
	struct btrfs_root *reloc_root;
	struct extent_buffer *eb;
	struct btrfs_root_item *root_item;
	struct btrfs_key root_key;
	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;
1275
	root_key.offset = objectid;
1276

1277 1278 1279 1280 1281 1282 1283 1284 1285 1286 1287 1288 1289 1290 1291 1292 1293 1294 1295 1296
	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);

		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);
	}
1297 1298 1299 1300 1301

	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);
1302 1303 1304 1305 1306 1307 1308

	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;
	}
1309 1310 1311 1312 1313 1314 1315 1316 1317 1318 1319 1320 1321

	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);

	reloc_root = btrfs_read_fs_root_no_radix(root->fs_info->tree_root,
						 &root_key);
	BUG_ON(IS_ERR(reloc_root));
	reloc_root->last_trans = trans->transid;
1322 1323 1324 1325 1326 1327 1328 1329 1330 1331 1332 1333 1334 1335 1336 1337 1338 1339 1340 1341 1342 1343 1344 1345 1346 1347 1348 1349 1350 1351 1352
	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;
	int clear_rsv = 0;

	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;

	if (!trans->block_rsv) {
		trans->block_rsv = rc->block_rsv;
		clear_rsv = 1;
	}
	reloc_root = create_reloc_root(trans, root, root->root_key.objectid);
	if (clear_rsv)
		trans->block_rsv = NULL;
1353 1354 1355 1356 1357 1358 1359 1360 1361 1362 1363 1364 1365 1366 1367 1368 1369 1370

	__add_reloc_root(reloc_root);
	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 del = 0;
	int ret;

	if (!root->reloc_root)
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		goto out;
1372 1373 1374 1375

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

1376 1377
	if (root->fs_info->reloc_ctl->merge_reloc_tree &&
	    btrfs_root_refs(root_item) == 0) {
1378 1379 1380 1381 1382 1383 1384 1385 1386 1387 1388 1389 1390 1391 1392
		root->reloc_root = NULL;
		del = 1;
	}

	__update_reloc_root(reloc_root, del);

	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);
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Chris Mason 已提交
1393 1394

out:
1395 1396 1397 1398 1399 1400 1401 1402 1403 1404 1405 1406 1407 1408 1409 1410 1411 1412 1413 1414 1415 1416
	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);

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		if (objectid < btrfs_ino(&entry->vfs_inode))
1418
			node = node->rb_left;
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		else if (objectid > btrfs_ino(&entry->vfs_inode))
1420 1421 1422 1423 1424 1425 1426
			node = node->rb_right;
		else
			break;
	}
	if (!node) {
		while (prev) {
			entry = rb_entry(prev, struct btrfs_inode, rb_node);
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			if (objectid <= btrfs_ino(&entry->vfs_inode)) {
1428 1429 1430 1431 1432 1433 1434 1435 1436 1437 1438 1439 1440 1441
				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;
		}

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		objectid = btrfs_ino(&entry->vfs_inode) + 1;
1443 1444 1445 1446 1447 1448 1449 1450 1451 1452 1453 1454 1455 1456 1457 1458 1459 1460 1461 1462 1463 1464 1465 1466 1467 1468 1469 1470 1471 1472 1473 1474 1475 1476 1477
		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;
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	ret = btrfs_lookup_file_extent(NULL, root, path, btrfs_ino(reloc_inode),
1479 1480 1481 1482 1483 1484 1485 1486 1487 1488 1489 1490 1491 1492 1493 1494 1495 1496 1497 1498 1499 1500
				       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)) {
		ret = 1;
		goto out;
	}

1501
	*new_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1502 1503 1504 1505 1506 1507 1508 1509 1510 1511
	ret = 0;
out:
	btrfs_free_path(path);
	return ret;
}

/*
 * update file extent items in the tree leaf to point to
 * the new locations.
 */
1512 1513 1514 1515 1516
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)
1517 1518 1519 1520 1521 1522
{
	struct btrfs_key key;
	struct btrfs_file_extent_item *fi;
	struct inode *inode = NULL;
	u64 parent;
	u64 bytenr;
1523
	u64 new_bytenr = 0;
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 1553 1554 1555 1556 1557 1558 1559 1560 1561 1562 1563 1564 1565
	u64 num_bytes;
	u64 end;
	u32 nritems;
	u32 i;
	int ret;
	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;
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			} else if (inode && btrfs_ino(inode) < key.objectid) {
1567
				btrfs_add_delayed_iput(inode);
1568 1569
				inode = find_next_inode(root, key.objectid);
			}
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Li Zefan 已提交
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			if (inode && btrfs_ino(inode) == key.objectid) {
1571 1572 1573 1574 1575 1576 1577 1578 1579 1580 1581 1582 1583 1584 1585 1586 1587 1588 1589 1590 1591
				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,
						      key.offset, end,
						      GFP_NOFS);
				if (!ret)
					continue;

				btrfs_drop_extent_cache(inode, key.offset, end,
							1);
				unlock_extent(&BTRFS_I(inode)->io_tree,
					      key.offset, end, GFP_NOFS);
			}
		}

		ret = get_new_location(rc->data_inode, &new_bytenr,
				       bytenr, num_bytes);
1592 1593
		if (ret > 0) {
			WARN_ON(1);
1594
			continue;
1595
		}
1596 1597 1598 1599 1600 1601 1602 1603 1604 1605 1606 1607 1608 1609 1610 1611 1612 1613 1614
		BUG_ON(ret < 0);

		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),
					   key.objectid, key.offset);
		BUG_ON(ret);

		ret = btrfs_free_extent(trans, root, bytenr, num_bytes,
					parent, btrfs_header_owner(leaf),
					key.objectid, key.offset);
		BUG_ON(ret);
	}
	if (dirty)
		btrfs_mark_buffer_dirty(leaf);
1615 1616
	if (inode)
		btrfs_add_delayed_iput(inode);
1617 1618 1619 1620 1621 1622 1623 1624 1625 1626 1627 1628 1629 1630 1631 1632 1633 1634 1635 1636 1637 1638 1639
	return 0;
}

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.
 */
1640 1641 1642 1643 1644
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)
1645 1646 1647 1648 1649 1650 1651 1652 1653 1654
{
	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;
1655
	int cow = 0;
1656 1657 1658 1659 1660 1661 1662 1663
	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);
1664
again:
1665 1666 1667 1668 1669 1670 1671 1672 1673 1674 1675 1676 1677
	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;
	}

1678 1679 1680 1681
	if (cow) {
		ret = btrfs_cow_block(trans, dest, eb, NULL, 0, &eb);
		BUG_ON(ret);
	}
1682 1683 1684 1685 1686 1687 1688 1689 1690 1691 1692 1693 1694 1695 1696 1697 1698 1699 1700 1701 1702 1703 1704 1705 1706 1707 1708 1709 1710 1711 1712 1713 1714 1715 1716 1717 1718 1719 1720 1721 1722 1723 1724
	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;
		}

		if (new_bytenr > 0 && new_bytenr == old_bytenr) {
			WARN_ON(1);
			ret = level;
			break;
		}

		if (new_bytenr == 0 || old_ptr_gen > last_snapshot ||
		    memcmp_node_keys(parent, slot, path, level)) {
1725
			if (level <= lowest_level) {
1726 1727 1728 1729 1730 1731
				ret = 0;
				break;
			}

			eb = read_tree_block(dest, old_bytenr, blocksize,
					     old_ptr_gen);
1732
			BUG_ON(!eb);
1733
			btrfs_tree_lock(eb);
1734 1735 1736 1737
			if (cow) {
				ret = btrfs_cow_block(trans, dest, eb, parent,
						      slot, &eb);
				BUG_ON(ret);
1738
			}
1739
			btrfs_set_lock_blocking(eb);
1740 1741 1742 1743 1744 1745 1746 1747

			btrfs_tree_unlock(parent);
			free_extent_buffer(parent);

			parent = eb;
			continue;
		}

1748 1749 1750 1751 1752 1753 1754
		if (!cow) {
			btrfs_tree_unlock(parent);
			free_extent_buffer(parent);
			cow = 1;
			goto again;
		}

1755 1756
		btrfs_node_key_to_cpu(path->nodes[level], &key,
				      path->slots[level]);
1757
		btrfs_release_path(path);
1758 1759 1760 1761 1762 1763 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 1799 1800 1801 1802 1803 1804 1805 1806 1807 1808 1809 1810 1811 1812 1813 1814 1815 1816 1817 1818 1819 1820 1821 1822 1823 1824 1825 1826 1827 1828 1829 1830 1831 1832 1833 1834 1835 1836 1837 1838 1839 1840 1841 1842 1843 1844 1845 1846 1847 1848 1849 1850 1851 1852 1853 1854 1855 1856 1857 1858 1859 1860 1861 1862 1863 1864 1865 1866 1867 1868 1869 1870 1871 1872 1873 1874 1875 1876 1877 1878 1879 1880 1881 1882 1883 1884 1885 1886 1887 1888 1889 1890 1891 1892 1893 1894 1895 1896 1897 1898 1899 1900

		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,
					src->root_key.objectid, level - 1, 0);
		BUG_ON(ret);
		ret = btrfs_inc_extent_ref(trans, dest, new_bytenr, blocksize,
					0, dest->root_key.objectid, level - 1,
					0);
		BUG_ON(ret);

		ret = btrfs_free_extent(trans, src, new_bytenr, blocksize,
					path->nodes[level]->start,
					src->root_key.objectid, level - 1, 0);
		BUG_ON(ret);

		ret = btrfs_free_extent(trans, dest, old_bytenr, blocksize,
					0, dest->root_key.objectid, level - 1,
					0);
		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);
		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
1901
	u64 ino;
1902 1903 1904 1905 1906 1907 1908 1909 1910 1911 1912 1913

	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
1914
		ino = btrfs_ino(inode);
1915

L
Li Zefan 已提交
1916
		if (ino > max_key->objectid) {
1917 1918 1919 1920
			iput(inode);
			break;
		}

L
Li Zefan 已提交
1921
		objectid = ino + 1;
1922 1923 1924
		if (!S_ISREG(inode->i_mode))
			continue;

L
Li Zefan 已提交
1925
		if (unlikely(min_key->objectid == ino)) {
1926 1927 1928 1929 1930 1931 1932 1933 1934 1935 1936 1937
			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
1938
		if (unlikely(max_key->objectid == ino)) {
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 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993
			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 */
		lock_extent(&BTRFS_I(inode)->io_tree, start, end, GFP_NOFS);
		btrfs_drop_extent_cache(inode, start, end, 1);
		unlock_extent(&BTRFS_I(inode)->io_tree, start, end, GFP_NOFS);
	}
	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;
	struct btrfs_trans_handle *trans;
	struct btrfs_root *reloc_root;
	struct btrfs_root_item *root_item;
	struct btrfs_path *path;
1994
	struct extent_buffer *leaf;
1995 1996 1997 1998 1999 2000
	unsigned long nr;
	int level;
	int max_level;
	int replaced = 0;
	int ret;
	int err = 0;
2001
	u32 min_reserved;
2002 2003 2004 2005

	path = btrfs_alloc_path();
	if (!path)
		return -ENOMEM;
J
Josef Bacik 已提交
2006
	path->reada = 1;
2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022

	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);
2023
		path->lowest_level = 0;
2024 2025 2026 2027 2028 2029 2030 2031 2032 2033 2034 2035
		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);
	}

2036 2037
	min_reserved = root->nodesize * (BTRFS_MAX_LEVEL - 1) * 2;
	memset(&next_key, 0, sizeof(next_key));
2038

2039 2040
	while (1) {
		trans = btrfs_start_transaction(root, 0);
2041
		BUG_ON(IS_ERR(trans));
2042
		trans->block_rsv = rc->block_rsv;
2043

2044
		ret = btrfs_block_rsv_refill(root, rc->block_rsv, min_reserved);
2045 2046 2047 2048 2049
		if (ret) {
			BUG_ON(ret != -EAGAIN);
			ret = btrfs_commit_transaction(trans, root);
			BUG_ON(ret);
			continue;
2050 2051 2052 2053 2054 2055 2056 2057 2058 2059 2060 2061 2062 2063 2064 2065 2066
		}

		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 {
2067 2068
			ret = replace_path(trans, root, reloc_root, path,
					   &next_key, level, max_level);
2069 2070 2071 2072 2073 2074 2075 2076 2077 2078 2079 2080 2081 2082 2083 2084 2085 2086 2087 2088 2089 2090 2091 2092 2093 2094 2095
		}
		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;

		nr = trans->blocks_used;
2096
		btrfs_end_transaction_throttle(trans, root);
2097 2098 2099 2100 2101 2102 2103 2104 2105 2106 2107 2108 2109 2110 2111 2112 2113 2114 2115 2116 2117 2118 2119 2120 2121

		btrfs_btree_balance_dirty(root, nr);

		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);
2122
		btrfs_update_reloc_root(trans, root);
2123 2124 2125
	}

	nr = trans->blocks_used;
2126
	btrfs_end_transaction_throttle(trans, root);
2127 2128 2129 2130 2131 2132 2133 2134 2135

	btrfs_btree_balance_dirty(root, nr);

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

	return err;
}

2136 2137
static noinline_for_stack
int prepare_to_merge(struct reloc_control *rc, int err)
2138
{
2139
	struct btrfs_root *root = rc->extent_root;
2140
	struct btrfs_root *reloc_root;
2141 2142 2143 2144 2145
	struct btrfs_trans_handle *trans;
	LIST_HEAD(reloc_roots);
	u64 num_bytes = 0;
	int ret;

C
Chris Mason 已提交
2146
	mutex_lock(&root->fs_info->reloc_mutex);
2147 2148
	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
2149 2150
	mutex_unlock(&root->fs_info->reloc_mutex);

2151 2152 2153
again:
	if (!err) {
		num_bytes = rc->merging_rsv_size;
2154
		ret = btrfs_block_rsv_add(root, rc->block_rsv, num_bytes);
2155 2156 2157 2158
		if (ret)
			err = ret;
	}

2159
	trans = btrfs_join_transaction(rc->extent_root);
2160 2161 2162 2163 2164 2165
	if (IS_ERR(trans)) {
		if (!err)
			btrfs_block_rsv_release(rc->extent_root,
						rc->block_rsv, num_bytes);
		return PTR_ERR(trans);
	}
2166 2167 2168 2169 2170 2171 2172 2173 2174

	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;
		}
	}
2175

2176 2177 2178 2179 2180 2181
	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);
2182 2183 2184 2185 2186 2187

		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);

2188 2189 2190 2191 2192 2193
		/*
		 * 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);
2194 2195
		btrfs_update_reloc_root(trans, root);

2196 2197
		list_add(&reloc_root->root_list, &reloc_roots);
	}
2198

2199
	list_splice(&reloc_roots, &rc->reloc_roots);
2200

2201 2202 2203 2204 2205
	if (!err)
		btrfs_commit_transaction(trans, rc->extent_root);
	else
		btrfs_end_transaction(trans, rc->extent_root);
	return err;
2206 2207
}

2208 2209
static noinline_for_stack
int merge_reloc_roots(struct reloc_control *rc)
2210 2211
{
	struct btrfs_root *root;
2212 2213 2214 2215 2216 2217
	struct btrfs_root *reloc_root;
	LIST_HEAD(reloc_roots);
	int found = 0;
	int ret;
again:
	root = rc->extent_root;
C
Chris Mason 已提交
2218 2219 2220 2221 2222 2223 2224 2225

	/*
	 * 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);
2226
	list_splice_init(&rc->reloc_roots, &reloc_roots);
C
Chris Mason 已提交
2227
	mutex_unlock(&root->fs_info->reloc_mutex);
2228

2229 2230 2231 2232
	while (!list_empty(&reloc_roots)) {
		found = 1;
		reloc_root = list_entry(reloc_roots.next,
					struct btrfs_root, root_list);
2233

2234 2235 2236 2237 2238
		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);
2239

2240 2241 2242 2243 2244 2245
			ret = merge_reloc_root(rc, root);
			BUG_ON(ret);
		} else {
			list_del_init(&reloc_root->root_list);
		}
		btrfs_drop_snapshot(reloc_root, rc->block_rsv, 0);
2246 2247
	}

2248 2249 2250 2251
	if (found) {
		found = 0;
		goto again;
	}
2252 2253 2254 2255 2256 2257 2258 2259 2260 2261 2262 2263 2264 2265 2266 2267 2268 2269 2270 2271 2272 2273 2274 2275 2276 2277 2278 2279 2280 2281
	BUG_ON(!RB_EMPTY_ROOT(&rc->reloc_root_tree.rb_root));
	return 0;
}

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);
}

2282 2283 2284 2285 2286
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)
2287 2288 2289
{
	struct backref_node *next;
	struct btrfs_root *root;
2290 2291
	int index = 0;

2292 2293 2294 2295 2296
	next = node;
	while (1) {
		cond_resched();
		next = walk_up_backref(next, edges, &index);
		root = next->root;
2297 2298
		BUG_ON(!root);
		BUG_ON(!root->ref_cows);
2299 2300 2301 2302 2303 2304

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

2305 2306 2307 2308 2309 2310 2311 2312 2313 2314 2315
		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);
2316 2317 2318
			break;
		}

2319
		WARN_ON(1);
2320 2321 2322 2323 2324
		root = NULL;
		next = walk_down_backref(edges, &index);
		if (!next || next->level <= node->level)
			break;
	}
2325 2326
	if (!root)
		return NULL;
2327

2328 2329 2330 2331 2332 2333 2334 2335
	*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];
2336 2337 2338 2339
	}
	return root;
}

2340 2341 2342 2343 2344 2345
/*
 * 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.
 */
2346 2347 2348 2349
static noinline_for_stack
struct btrfs_root *select_one_root(struct btrfs_trans_handle *trans,
				   struct backref_node *node)
{
2350 2351 2352
	struct backref_node *next;
	struct btrfs_root *root;
	struct btrfs_root *fs_root = NULL;
2353
	struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2354 2355 2356 2357 2358 2359 2360 2361 2362
	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
2363
		/* no other choice for non-references counted tree */
2364 2365 2366 2367 2368 2369 2370 2371 2372 2373 2374 2375 2376 2377 2378 2379 2380
		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;
2381 2382 2383
}

static noinline_for_stack
2384 2385
u64 calcu_metadata_size(struct reloc_control *rc,
			struct backref_node *node, int reserve)
2386
{
2387 2388 2389 2390 2391 2392 2393 2394 2395 2396 2397 2398 2399 2400 2401 2402 2403 2404 2405 2406 2407 2408 2409 2410 2411 2412 2413 2414
	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;
2415 2416
}

2417 2418 2419
static int reserve_metadata_space(struct btrfs_trans_handle *trans,
				  struct reloc_control *rc,
				  struct backref_node *node)
2420
{
2421 2422 2423 2424 2425
	struct btrfs_root *root = rc->extent_root;
	u64 num_bytes;
	int ret;

	num_bytes = calcu_metadata_size(rc, node, 1) * 2;
2426

2427
	trans->block_rsv = rc->block_rsv;
2428
	ret = btrfs_block_rsv_add(root, rc->block_rsv, num_bytes);
2429 2430 2431 2432
	if (ret) {
		if (ret == -EAGAIN)
			rc->commit_transaction = 1;
		return ret;
2433
	}
2434 2435 2436 2437 2438 2439 2440 2441 2442

	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);
2443 2444 2445 2446 2447 2448 2449 2450 2451 2452
}

/*
 * 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,
2453
			 struct reloc_control *rc,
2454 2455 2456 2457 2458 2459 2460 2461 2462 2463 2464 2465 2466 2467 2468 2469 2470 2471 2472 2473
			 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;
2474
	rc->backref_cache.path[node->level] = node;
2475 2476 2477 2478
	list_for_each_entry(edge, &node->upper, list[LOWER]) {
		cond_resched();

		upper = edge->node[UPPER];
2479 2480 2481 2482 2483 2484 2485 2486 2487 2488 2489 2490
		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;
			}
2491
			drop_node_buffer(upper);
2492
		}
2493 2494 2495 2496 2497 2498 2499 2500 2501

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

2502 2503 2504 2505 2506 2507
			if (!upper->eb) {
				upper->eb = path->nodes[upper->level];
				path->nodes[upper->level] = NULL;
			} else {
				BUG_ON(upper->eb != path->nodes[upper->level]);
			}
2508

2509 2510
			upper->locked = 1;
			path->locks[upper->level] = 0;
2511

2512
			slot = path->slots[upper->level];
2513
			btrfs_release_path(path);
2514 2515 2516 2517 2518 2519 2520
		} else {
			ret = btrfs_bin_search(upper->eb, key, upper->level,
					       &slot);
			BUG_ON(ret);
		}

		bytenr = btrfs_node_blockptr(upper->eb, slot);
2521 2522
		if (lowest) {
			BUG_ON(bytenr != node->bytenr);
2523
		} else {
2524 2525
			if (node->eb->start == bytenr)
				goto next;
2526 2527 2528 2529 2530
		}

		blocksize = btrfs_level_size(root, node->level);
		generation = btrfs_node_ptr_generation(upper->eb, slot);
		eb = read_tree_block(root, bytenr, blocksize, generation);
2531 2532 2533 2534
		if (!eb) {
			err = -EIO;
			goto next;
		}
2535 2536 2537 2538 2539 2540
		btrfs_tree_lock(eb);
		btrfs_set_lock_blocking(eb);

		if (!node->eb) {
			ret = btrfs_cow_block(trans, root, eb, upper->eb,
					      slot, &eb);
2541 2542
			btrfs_tree_unlock(eb);
			free_extent_buffer(eb);
2543 2544
			if (ret < 0) {
				err = ret;
2545
				goto next;
2546
			}
2547
			BUG_ON(node->eb != eb);
2548 2549 2550 2551 2552 2553 2554 2555 2556 2557 2558 2559 2560 2561 2562 2563 2564
		} 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),
						node->level, 0);
			BUG_ON(ret);

			ret = btrfs_drop_subtree(trans, root, eb, upper->eb);
			BUG_ON(ret);
		}
2565 2566 2567 2568 2569 2570 2571
next:
		if (!upper->pending)
			drop_node_buffer(upper);
		else
			unlock_node_buffer(upper);
		if (err)
			break;
2572
	}
2573 2574 2575 2576 2577 2578 2579

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

2580
	path->lowest_level = 0;
2581
	BUG_ON(err == -ENOSPC);
2582 2583 2584 2585
	return err;
}

static int link_to_upper(struct btrfs_trans_handle *trans,
2586
			 struct reloc_control *rc,
2587 2588 2589 2590 2591 2592
			 struct backref_node *node,
			 struct btrfs_path *path)
{
	struct btrfs_key key;

	btrfs_node_key_to_cpu(node->eb, &key, 0);
2593
	return do_relocation(trans, rc, node, &key, path, 0);
2594 2595 2596
}

static int finish_pending_nodes(struct btrfs_trans_handle *trans,
2597 2598
				struct reloc_control *rc,
				struct btrfs_path *path, int err)
2599
{
2600 2601
	LIST_HEAD(list);
	struct backref_cache *cache = &rc->backref_cache;
2602 2603 2604 2605 2606 2607 2608
	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,
2609 2610 2611
					  struct backref_node, list);
			list_move_tail(&node->list, &list);
			BUG_ON(!node->pending);
2612

2613 2614 2615 2616 2617
			if (!err) {
				ret = link_to_upper(trans, rc, node, path);
				if (ret < 0)
					err = ret;
			}
2618
		}
2619
		list_splice_init(&list, &cache->pending[level]);
2620 2621 2622 2623 2624
	}
	return err;
}

static void mark_block_processed(struct reloc_control *rc,
2625 2626 2627 2628 2629 2630 2631 2632
				 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)
2633 2634 2635 2636 2637
{
	u32 blocksize;
	if (node->level == 0 ||
	    in_block_group(node->bytenr, rc->block_group)) {
		blocksize = btrfs_level_size(rc->extent_root, node->level);
2638
		mark_block_processed(rc, node->bytenr, blocksize);
2639 2640 2641 2642 2643 2644 2645 2646 2647 2648 2649 2650 2651 2652 2653 2654 2655 2656 2657 2658 2659 2660
	}
	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;

2661
			__mark_block_processed(rc, next);
2662 2663 2664 2665 2666 2667 2668 2669 2670 2671 2672 2673 2674

			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);
	}
}

2675 2676 2677 2678 2679 2680 2681
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;
2682 2683 2684 2685 2686 2687 2688 2689 2690 2691
}

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);
2692
	BUG_ON(!eb);
2693 2694 2695 2696 2697 2698 2699 2700 2701 2702 2703 2704 2705 2706 2707 2708 2709 2710 2711 2712 2713 2714 2715 2716 2717 2718 2719 2720 2721
	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);
	readahead_tree_block(rc->extent_root, block->bytenr,
			     block->key.objectid, block->key.offset);
	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;
2722 2723 2724 2725 2726
	int release = 0;
	int ret = 0;

	if (!node)
		return 0;
2727

2728
	BUG_ON(node->processed);
2729
	root = select_one_root(trans, node);
2730
	if (root == ERR_PTR(-ENOENT)) {
2731
		update_processed_blocks(rc, node);
2732
		goto out;
2733 2734
	}

2735 2736 2737
	if (!root || root->ref_cows) {
		ret = reserve_metadata_space(trans, rc, node);
		if (ret)
2738
			goto out;
2739
		release = 1;
2740 2741
	}

2742 2743 2744 2745 2746 2747 2748 2749 2750 2751 2752 2753
	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);
2754
			btrfs_release_path(path);
2755 2756 2757 2758 2759 2760 2761 2762
			if (ret > 0)
				ret = 0;
		}
		if (!ret)
			update_processed_blocks(rc, node);
	} else {
		ret = do_relocation(trans, rc, node, key, path, 1);
	}
2763
out:
2764 2765 2766 2767 2768
	if (ret || node->level == 0 || node->cowonly) {
		if (release)
			release_metadata_space(rc, node);
		remove_backref_node(&rc->backref_cache, node);
	}
2769 2770 2771 2772 2773 2774 2775 2776 2777 2778 2779 2780 2781 2782 2783 2784 2785 2786 2787 2788 2789 2790 2791 2792 2793 2794 2795 2796 2797 2798 2799 2800 2801 2802 2803 2804 2805 2806 2807 2808 2809
	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();
	if (!path)
		return -ENOMEM;

	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);
		if (!block->key_ready)
			get_tree_block_key(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);

2810
		node = build_backref_tree(rc, &block->key,
2811 2812 2813 2814 2815 2816 2817 2818 2819
					  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) {
2820 2821
			if (ret != -EAGAIN || rb_node == rb_first(blocks))
				err = ret;
2822 2823 2824 2825 2826 2827
			goto out;
		}
		rb_node = rb_next(rb_node);
	}
out:
	free_block_list(blocks);
2828
	err = finish_pending_nodes(trans, rc, path, err);
2829 2830 2831 2832 2833

	btrfs_free_path(path);
	return err;
}

2834 2835 2836 2837 2838 2839 2840 2841 2842 2843 2844 2845 2846 2847 2848 2849 2850 2851 2852 2853 2854 2855 2856 2857 2858 2859 2860 2861 2862 2863 2864 2865 2866 2867 2868 2869 2870 2871 2872 2873 2874 2875 2876 2877
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;

		lock_extent(&BTRFS_I(inode)->io_tree, start, end, GFP_NOFS);
		num_bytes = end + 1 - start;
		ret = btrfs_prealloc_file_range(inode, 0, start,
						num_bytes, num_bytes,
						end + 1, &alloc_hint);
		unlock_extent(&BTRFS_I(inode)->io_tree, start, end, GFP_NOFS);
		if (ret)
			break;
		nr++;
	}
	btrfs_free_reserved_data_space(inode, cluster->end +
				       1 - cluster->start);
out:
	mutex_unlock(&inode->i_mutex);
	return ret;
}

2878
static noinline_for_stack
2879 2880 2881 2882 2883 2884 2885 2886
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;

2887
	em = alloc_extent_map();
2888 2889 2890 2891 2892 2893 2894 2895 2896 2897 2898 2899 2900 2901 2902 2903 2904 2905 2906 2907 2908 2909 2910 2911 2912 2913 2914
	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);

	lock_extent(&BTRFS_I(inode)->io_tree, start, end, GFP_NOFS);
	while (1) {
		write_lock(&em_tree->lock);
		ret = add_extent_mapping(em_tree, em);
		write_unlock(&em_tree->lock);
		if (ret != -EEXIST) {
			free_extent_map(em);
			break;
		}
		btrfs_drop_extent_cache(inode, start, end, 0);
	}
	unlock_extent(&BTRFS_I(inode)->io_tree, start, end, GFP_NOFS);
	return ret;
}

static int relocate_file_extent_cluster(struct inode *inode,
					struct file_extent_cluster *cluster)
2915 2916 2917
{
	u64 page_start;
	u64 page_end;
2918 2919
	u64 offset = BTRFS_I(inode)->index_cnt;
	unsigned long index;
2920 2921 2922
	unsigned long last_index;
	struct page *page;
	struct file_ra_state *ra;
2923
	gfp_t mask = btrfs_alloc_write_mask(inode->i_mapping);
2924
	int nr = 0;
2925 2926
	int ret = 0;

2927 2928 2929
	if (!cluster->nr)
		return 0;

2930 2931 2932 2933
	ra = kzalloc(sizeof(*ra), GFP_NOFS);
	if (!ra)
		return -ENOMEM;

2934 2935 2936
	ret = prealloc_file_extent_cluster(inode, cluster);
	if (ret)
		goto out;
2937

2938
	file_ra_state_init(ra, inode->i_mapping);
2939

2940 2941
	ret = setup_extent_mapping(inode, cluster->start - offset,
				   cluster->end - offset, cluster->start);
2942
	if (ret)
2943
		goto out;
2944

2945 2946
	index = (cluster->start - offset) >> PAGE_CACHE_SHIFT;
	last_index = (cluster->end - offset) >> PAGE_CACHE_SHIFT;
2947
	while (index <= last_index) {
2948 2949 2950 2951
		ret = btrfs_delalloc_reserve_metadata(inode, PAGE_CACHE_SIZE);
		if (ret)
			goto out;

2952
		page = find_lock_page(inode->i_mapping, index);
2953
		if (!page) {
2954 2955 2956
			page_cache_sync_readahead(inode->i_mapping,
						  ra, NULL, index,
						  last_index + 1 - index);
2957
			page = find_or_create_page(inode->i_mapping, index,
2958
						   mask);
2959
			if (!page) {
2960 2961
				btrfs_delalloc_release_metadata(inode,
							PAGE_CACHE_SIZE);
2962
				ret = -ENOMEM;
2963
				goto out;
2964
			}
2965
		}
2966 2967 2968 2969 2970 2971 2972

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

2973 2974 2975 2976 2977 2978
		if (!PageUptodate(page)) {
			btrfs_readpage(NULL, page);
			lock_page(page);
			if (!PageUptodate(page)) {
				unlock_page(page);
				page_cache_release(page);
2979 2980
				btrfs_delalloc_release_metadata(inode,
							PAGE_CACHE_SIZE);
2981
				ret = -EIO;
2982
				goto out;
2983 2984 2985 2986 2987
			}
		}

		page_start = (u64)page->index << PAGE_CACHE_SHIFT;
		page_end = page_start + PAGE_CACHE_SIZE - 1;
2988 2989 2990 2991

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

2992 2993
		set_page_extent_mapped(page);

2994 2995 2996 2997
		if (nr < cluster->nr &&
		    page_start + offset == cluster->boundary[nr]) {
			set_extent_bits(&BTRFS_I(inode)->io_tree,
					page_start, page_end,
2998
					EXTENT_BOUNDARY, GFP_NOFS);
2999 3000
			nr++;
		}
3001

3002
		btrfs_set_extent_delalloc(inode, page_start, page_end, NULL);
3003 3004
		set_page_dirty(page);

3005 3006
		unlock_extent(&BTRFS_I(inode)->io_tree,
			      page_start, page_end, GFP_NOFS);
3007 3008
		unlock_page(page);
		page_cache_release(page);
3009 3010

		index++;
3011 3012
		balance_dirty_pages_ratelimited(inode->i_mapping);
		btrfs_throttle(BTRFS_I(inode)->root);
3013
	}
3014
	WARN_ON(nr != cluster->nr);
3015
out:
3016 3017 3018 3019 3020
	kfree(ra);
	return ret;
}

static noinline_for_stack
3021 3022
int relocate_data_extent(struct inode *inode, struct btrfs_key *extent_key,
			 struct file_extent_cluster *cluster)
3023
{
3024
	int ret;
3025

3026 3027 3028 3029 3030
	if (cluster->nr > 0 && extent_key->objectid != cluster->end + 1) {
		ret = relocate_file_extent_cluster(inode, cluster);
		if (ret)
			return ret;
		cluster->nr = 0;
3031 3032
	}

3033 3034 3035 3036 3037 3038 3039 3040 3041 3042 3043 3044 3045 3046 3047
	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;
3048 3049 3050 3051 3052 3053 3054 3055 3056 3057 3058 3059 3060 3061 3062 3063 3064 3065 3066 3067 3068 3069 3070 3071 3072 3073 3074 3075 3076 3077 3078 3079 3080 3081 3082 3083 3084 3085 3086 3087 3088 3089 3090 3091 3092 3093 3094 3095 3096 3097 3098 3099 3100 3101 3102 3103 3104 3105 3106 3107 3108 3109 3110 3111 3112 3113 3114 3115 3116 3117 3118 3119 3120 3121 3122 3123 3124 3125 3126
}

#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;
	int generation;

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

	if (item_size >= sizeof(*ei) + sizeof(*bi)) {
		ei = btrfs_item_ptr(eb, path->slots[0],
				struct btrfs_extent_item);
		bi = (struct btrfs_tree_block_info *)(ei + 1);
		generation = btrfs_extent_generation(eb, ei);
		level = btrfs_tree_block_level(eb, bi);
	} 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);
3127 3128
		if (ret < 0)
			return ret;
3129 3130 3131 3132 3133 3134 3135 3136 3137
		BUG_ON(ref_owner >= BTRFS_MAX_LEVEL);
		level = (int)ref_owner;
		/* FIXME: get real generation */
		generation = 0;
#else
		BUG();
#endif
	}

3138
	btrfs_release_path(path);
3139 3140 3141 3142 3143 3144 3145 3146 3147 3148 3149 3150 3151 3152 3153 3154 3155 3156 3157 3158 3159 3160 3161 3162 3163 3164 3165 3166 3167 3168 3169 3170 3171 3172 3173 3174 3175 3176 3177 3178 3179 3180 3181 3182 3183 3184 3185 3186 3187 3188 3189 3190 3191 3192 3193 3194 3195 3196 3197 3198 3199 3200 3201 3202 3203 3204 3205 3206 3207 3208 3209

	BUG_ON(level == -1);

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

	block->bytenr = extent_key->objectid;
	block->key.objectid = extent_key->offset;
	block->key.offset = generation;
	block->level = level;
	block->key_ready = 0;

	rb_node = tree_insert(blocks, block->bytenr, &block->rb_node);
	BUG_ON(rb_node);

	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;

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

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

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

	key.objectid = bytenr;
	key.type = BTRFS_EXTENT_ITEM_KEY;
	key.offset = blocksize;

	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;
	BUG_ON(ret);

	btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
	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;

3210 3211
	ret = btrfs_lookup_extent_info(NULL, rc->extent_root,
				       eb->start, eb->len, NULL, &flags);
3212 3213 3214 3215 3216 3217 3218 3219 3220
	BUG_ON(ret);

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

3221 3222 3223 3224 3225 3226 3227 3228 3229 3230 3231 3232 3233 3234 3235 3236 3237 3238
static int delete_block_group_cache(struct btrfs_fs_info *fs_info,
				    struct inode *inode, u64 ino)
{
	struct btrfs_key key;
	struct btrfs_path *path;
	struct btrfs_root *root = fs_info->tree_root;
	struct btrfs_trans_handle *trans;
	unsigned long nr;
	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);
3239
	if (IS_ERR_OR_NULL(inode) || is_bad_inode(inode)) {
3240 3241 3242 3243 3244 3245 3246 3247 3248 3249 3250 3251
		if (inode && !IS_ERR(inode))
			iput(inode);
		return -ENOENT;
	}

truncate:
	path = btrfs_alloc_path();
	if (!path) {
		ret = -ENOMEM;
		goto out;
	}

3252
	trans = btrfs_join_transaction(root);
3253 3254
	if (IS_ERR(trans)) {
		btrfs_free_path(path);
3255
		ret = PTR_ERR(trans);
3256 3257 3258 3259 3260 3261 3262 3263 3264 3265 3266 3267 3268 3269
		goto out;
	}

	ret = btrfs_truncate_free_space_cache(root, trans, path, inode);

	btrfs_free_path(path);
	nr = trans->blocks_used;
	btrfs_end_transaction(trans, root);
	btrfs_btree_balance_dirty(root, nr);
out:
	iput(inode);
	return ret;
}

3270 3271 3272 3273 3274 3275 3276 3277 3278 3279 3280 3281 3282 3283 3284 3285 3286 3287 3288 3289 3290 3291 3292 3293 3294 3295 3296 3297 3298 3299 3300
/*
 * 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);

3301 3302 3303 3304 3305 3306 3307 3308 3309 3310 3311 3312 3313 3314 3315
	/*
	 * 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
3316
	path->reada = 1;
3317

3318 3319 3320 3321 3322 3323 3324 3325
	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;
3326 3327 3328 3329
	if (ref_offset > ((u64)-1 << 32))
		key.offset = 0;
	else
		key.offset = ref_offset;
3330 3331 3332 3333 3334 3335 3336 3337 3338 3339 3340 3341 3342 3343 3344 3345 3346 3347 3348 3349 3350 3351 3352 3353 3354 3355 3356 3357 3358 3359 3360 3361 3362 3363 3364 3365 3366 3367 3368 3369 3370 3371 3372 3373 3374 3375 3376 3377 3378 3379 3380 3381 3382 3383 3384 3385 3386 3387 3388 3389 3390 3391 3392 3393 3394 3395 3396 3397 3398 3399 3400 3401 3402 3403 3404 3405 3406 3407 3408 3409 3410 3411 3412 3413 3414 3415 3416 3417 3418 3419 3420 3421 3422 3423 3424 3425 3426 3427 3428 3429 3430 3431 3432 3433 3434 3435 3436 3437 3438 3439 3440 3441 3442 3443 3444 3445 3446 3447 3448 3449 3450 3451 3452 3453 3454

	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;
			}
			if (ret > 0) {
				WARN_ON(1);
				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]);
		if (key.objectid != ref_objectid ||
		    key.type != BTRFS_EXTENT_DATA_KEY) {
			WARN_ON(1);
			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);
			BUG_ON(rb_node);
		}
		if (counted)
			added = 1;
		else
			path->slots[0] = nritems;
next:
		path->slots[0]++;

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

/*
 * hepler to find all tree blocks that reference a given data extent
 */
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;
3455
	u32 blocksize = btrfs_level_size(rc->extent_root, 0);
3456 3457 3458 3459 3460 3461 3462 3463 3464 3465 3466 3467 3468 3469 3470 3471 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 3503 3504 3505 3506 3507 3508 3509 3510 3511 3512 3513 3514 3515 3516 3517 3518 3519 3520 3521 3522 3523 3524 3525 3526 3527
	int ret;
	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();
		}
		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]++;
	}
3528
	btrfs_release_path(path);
3529 3530 3531 3532 3533 3534 3535 3536 3537 3538
	if (err)
		free_block_list(blocks);
	return err;
}

/*
 * hepler to find next unprocessed extent
 */
static noinline_for_stack
int find_next_extent(struct btrfs_trans_handle *trans,
3539 3540
		     struct reloc_control *rc, struct btrfs_path *path,
		     struct btrfs_key *extent_key)
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 3566 3567 3568 3569 3570 3571 3572 3573 3574 3575 3576 3577 3578 3579 3580 3581 3582 3583 3584 3585 3586 3587 3588 3589 3590
{
	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;
		}

		if (key.type != BTRFS_EXTENT_ITEM_KEY ||
		    key.objectid + key.offset <= rc->search_start) {
			path->slots[0]++;
			goto next;
		}

		ret = find_first_extent_bit(&rc->processed_blocks,
					    key.objectid, &start, &end,
					    EXTENT_DIRTY);

		if (ret == 0 && start <= key.objectid) {
3591
			btrfs_release_path(path);
3592 3593 3594
			rc->search_start = end + 1;
		} else {
			rc->search_start = key.objectid + key.offset;
3595
			memcpy(extent_key, &key, sizeof(key));
3596 3597 3598
			return 0;
		}
	}
3599
	btrfs_release_path(path);
3600 3601 3602 3603 3604 3605
	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
3606 3607

	mutex_lock(&fs_info->reloc_mutex);
3608
	fs_info->reloc_ctl = rc;
C
Chris Mason 已提交
3609
	mutex_unlock(&fs_info->reloc_mutex);
3610 3611 3612 3613 3614
}

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
3615 3616

	mutex_lock(&fs_info->reloc_mutex);
3617
	fs_info->reloc_ctl = NULL;
C
Chris Mason 已提交
3618
	mutex_unlock(&fs_info->reloc_mutex);
3619 3620 3621 3622 3623 3624 3625 3626 3627 3628 3629 3630 3631 3632 3633 3634
}

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;
}

3635 3636 3637 3638 3639 3640 3641 3642 3643 3644 3645 3646 3647 3648 3649
static noinline_for_stack
int prepare_to_relocate(struct reloc_control *rc)
{
	struct btrfs_trans_handle *trans;
	int ret;

	rc->block_rsv = btrfs_alloc_block_rsv(rc->extent_root);
	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.
	 */
3650
	ret = btrfs_block_rsv_add(rc->extent_root, rc->block_rsv,
3651
				  rc->extent_root->nodesize * 256);
3652 3653 3654 3655 3656 3657 3658 3659 3660 3661 3662 3663
	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);

3664
	trans = btrfs_join_transaction(rc->extent_root);
3665
	BUG_ON(IS_ERR(trans));
3666 3667 3668
	btrfs_commit_transaction(trans, rc->extent_root);
	return 0;
}
3669

3670 3671 3672 3673 3674 3675 3676 3677 3678 3679 3680 3681
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;
	unsigned long nr;
	u64 flags;
	u32 item_size;
	int ret;
	int err = 0;
3682
	int progress = 0;
3683 3684

	path = btrfs_alloc_path();
3685
	if (!path)
3686
		return -ENOMEM;
J
Josef Bacik 已提交
3687
	path->reada = 1;
3688

3689 3690 3691 3692 3693
	ret = prepare_to_relocate(rc);
	if (ret) {
		err = ret;
		goto out_free;
	}
3694 3695

	while (1) {
3696
		progress++;
3697
		trans = btrfs_start_transaction(rc->extent_root, 0);
3698
		BUG_ON(IS_ERR(trans));
3699
restart:
3700 3701 3702 3703 3704 3705
		if (update_backref_cache(trans, &rc->backref_cache)) {
			btrfs_end_transaction(trans, rc->extent_root);
			continue;
		}

		ret = find_next_extent(trans, rc, path, &key);
3706 3707 3708 3709 3710 3711 3712 3713 3714
		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);
3715
		item_size = btrfs_item_size_nr(path->nodes[0], path->slots[0]);
3716 3717 3718 3719 3720 3721 3722 3723 3724 3725 3726 3727 3728 3729 3730 3731 3732 3733 3734 3735
		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) {
3736
				btrfs_release_path(path);
3737 3738 3739 3740 3741 3742 3743 3744 3745 3746 3747 3748 3749 3750 3751 3752 3753 3754 3755

				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 &&
3756
			   (flags & BTRFS_EXTENT_FLAG_DATA)) {
3757 3758
			ret = add_data_references(rc, &key, path, &blocks);
		} else {
3759
			btrfs_release_path(path);
3760 3761 3762
			ret = 0;
		}
		if (ret < 0) {
3763
			err = ret;
3764 3765 3766 3767 3768 3769
			break;
		}

		if (!RB_EMPTY_ROOT(&blocks)) {
			ret = relocate_tree_blocks(trans, rc, &blocks);
			if (ret < 0) {
3770 3771 3772 3773 3774 3775 3776 3777 3778
				if (ret != -EAGAIN) {
					err = ret;
					break;
				}
				rc->extents_found--;
				rc->search_start = key.objectid;
			}
		}

3779
		ret = btrfs_block_rsv_check(rc->extent_root, rc->block_rsv, 5);
3780 3781
		if (ret < 0) {
			if (ret != -EAGAIN) {
3782
				err = ret;
3783
				WARN_ON(1);
3784 3785
				break;
			}
3786
			rc->commit_transaction = 1;
3787 3788
		}

3789 3790 3791 3792 3793 3794 3795 3796 3797
		if (rc->commit_transaction) {
			rc->commit_transaction = 0;
			ret = btrfs_commit_transaction(trans, rc->extent_root);
			BUG_ON(ret);
		} else {
			nr = trans->blocks_used;
			btrfs_end_transaction_throttle(trans, rc->extent_root);
			btrfs_btree_balance_dirty(rc->extent_root, nr);
		}
3798 3799 3800 3801 3802
		trans = NULL;

		if (rc->stage == MOVE_DATA_EXTENTS &&
		    (flags & BTRFS_EXTENT_FLAG_DATA)) {
			rc->found_file_extent = 1;
3803
			ret = relocate_data_extent(rc->data_inode,
3804
						   &key, &rc->cluster);
3805 3806 3807 3808 3809 3810
			if (ret < 0) {
				err = ret;
				break;
			}
		}
	}
3811 3812 3813 3814 3815 3816 3817 3818 3819
	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;
		}
	}
3820

3821
	btrfs_release_path(path);
3822 3823
	clear_extent_bits(&rc->processed_blocks, 0, (u64)-1, EXTENT_DIRTY,
			  GFP_NOFS);
3824 3825 3826

	if (trans) {
		nr = trans->blocks_used;
3827
		btrfs_end_transaction_throttle(trans, rc->extent_root);
3828 3829 3830
		btrfs_btree_balance_dirty(rc->extent_root, nr);
	}

3831
	if (!err) {
3832 3833
		ret = relocate_file_extent_cluster(rc->data_inode,
						   &rc->cluster);
3834 3835 3836 3837
		if (ret < 0)
			err = ret;
	}

3838 3839
	rc->create_reloc_tree = 0;
	set_reloc_control(rc);
3840

3841 3842
	backref_cache_cleanup(&rc->backref_cache);
	btrfs_block_rsv_release(rc->extent_root, rc->block_rsv, (u64)-1);
3843

3844
	err = prepare_to_merge(rc, err);
3845 3846 3847

	merge_reloc_roots(rc);

3848
	rc->merge_reloc_tree = 0;
3849
	unset_reloc_control(rc);
3850
	btrfs_block_rsv_release(rc->extent_root, rc->block_rsv, (u64)-1);
3851 3852

	/* get rid of pinned extents */
3853
	trans = btrfs_join_transaction(rc->extent_root);
3854 3855 3856 3857
	if (IS_ERR(trans))
		err = PTR_ERR(trans);
	else
		btrfs_commit_transaction(trans, rc->extent_root);
3858 3859 3860
out_free:
	btrfs_free_block_rsv(rc->extent_root, rc->block_rsv);
	btrfs_free_path(path);
3861 3862 3863 3864
	return err;
}

static int __insert_orphan_inode(struct btrfs_trans_handle *trans,
3865
				 struct btrfs_root *root, u64 objectid)
3866 3867 3868 3869 3870 3871 3872 3873 3874 3875 3876 3877 3878 3879 3880 3881 3882 3883
{
	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);
3884
	btrfs_set_inode_size(leaf, item, 0);
3885
	btrfs_set_inode_mode(leaf, item, S_IFREG | 0600);
3886 3887
	btrfs_set_inode_flags(leaf, item, BTRFS_INODE_NOCOMPRESS |
					  BTRFS_INODE_PREALLOC);
3888
	btrfs_mark_buffer_dirty(leaf);
3889
	btrfs_release_path(path);
3890 3891 3892 3893 3894 3895 3896 3897 3898
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
 */
3899 3900 3901
static noinline_for_stack
struct inode *create_reloc_inode(struct btrfs_fs_info *fs_info,
				 struct btrfs_block_group_cache *group)
3902 3903 3904 3905 3906 3907 3908 3909 3910 3911 3912 3913 3914
{
	struct inode *inode = NULL;
	struct btrfs_trans_handle *trans;
	struct btrfs_root *root;
	struct btrfs_key key;
	unsigned long nr;
	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);

3915
	trans = btrfs_start_transaction(root, 6);
3916 3917
	if (IS_ERR(trans))
		return ERR_CAST(trans);
3918

3919
	err = btrfs_find_free_objectid(root, &objectid);
3920 3921 3922
	if (err)
		goto out;

3923
	err = __insert_orphan_inode(trans, root, objectid);
3924 3925 3926 3927 3928
	BUG_ON(err);

	key.objectid = objectid;
	key.type = BTRFS_INODE_ITEM_KEY;
	key.offset = 0;
3929
	inode = btrfs_iget(root->fs_info->sb, &key, root, NULL);
3930 3931 3932 3933 3934 3935 3936 3937 3938 3939 3940 3941 3942 3943 3944 3945
	BUG_ON(IS_ERR(inode) || is_bad_inode(inode));
	BTRFS_I(inode)->index_cnt = group->key.objectid;

	err = btrfs_orphan_add(trans, inode);
out:
	nr = trans->blocks_used;
	btrfs_end_transaction(trans, root);
	btrfs_btree_balance_dirty(root, nr);
	if (err) {
		if (inode)
			iput(inode);
		inode = ERR_PTR(err);
	}
	return inode;
}

3946 3947 3948 3949 3950 3951 3952 3953 3954 3955 3956
static struct reloc_control *alloc_reloc_control(void)
{
	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);
3957
	extent_io_tree_init(&rc->processed_blocks, NULL);
3958 3959 3960
	return rc;
}

3961 3962 3963 3964 3965 3966 3967
/*
 * 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;
3968 3969
	struct inode *inode;
	struct btrfs_path *path;
3970
	int ret;
3971
	int rw = 0;
3972 3973
	int err = 0;

3974
	rc = alloc_reloc_control();
3975 3976 3977
	if (!rc)
		return -ENOMEM;

3978
	rc->extent_root = extent_root;
3979

3980 3981 3982
	rc->block_group = btrfs_lookup_block_group(fs_info, group_start);
	BUG_ON(!rc->block_group);

3983 3984 3985 3986 3987 3988 3989 3990 3991
	if (!rc->block_group->ro) {
		ret = btrfs_set_block_group_ro(extent_root, rc->block_group);
		if (ret) {
			err = ret;
			goto out;
		}
		rw = 1;
	}

3992 3993 3994 3995 3996 3997 3998 3999 4000 4001 4002 4003 4004 4005 4006 4007 4008 4009 4010 4011
	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;
	}

4012 4013 4014 4015 4016 4017 4018 4019 4020 4021 4022
	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",
	       (unsigned long long)rc->block_group->key.objectid,
	       (unsigned long long)rc->block_group->flags);

Y
Yan, Zheng 已提交
4023 4024
	btrfs_start_delalloc_inodes(fs_info->tree_root, 0);
	btrfs_wait_ordered_extents(fs_info->tree_root, 0, 0);
4025 4026

	while (1) {
4027 4028 4029
		mutex_lock(&fs_info->cleaner_mutex);

		btrfs_clean_old_snapshots(fs_info->tree_root);
4030
		ret = relocate_block_group(rc);
4031 4032

		mutex_unlock(&fs_info->cleaner_mutex);
4033 4034
		if (ret < 0) {
			err = ret;
4035
			goto out;
4036 4037 4038 4039 4040 4041 4042 4043 4044 4045 4046 4047 4048 4049 4050 4051
		}

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

		printk(KERN_INFO "btrfs: found %llu extents\n",
			(unsigned long long)rc->extents_found);

		if (rc->stage == MOVE_DATA_EXTENTS && rc->found_file_extent) {
			btrfs_wait_ordered_range(rc->data_inode, 0, (u64)-1);
			invalidate_mapping_pages(rc->data_inode->i_mapping,
						 0, -1);
			rc->stage = UPDATE_DATA_PTRS;
		}
	}

4052 4053 4054 4055
	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);
4056 4057 4058 4059 4060

	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:
4061 4062
	if (err && rw)
		btrfs_set_block_group_rw(extent_root, rc->block_group);
4063 4064 4065 4066 4067 4068
	iput(rc->data_inode);
	btrfs_put_block_group(rc->block_group);
	kfree(rc);
	return err;
}

4069 4070 4071 4072 4073
static noinline_for_stack int mark_garbage_root(struct btrfs_root *root)
{
	struct btrfs_trans_handle *trans;
	int ret;

4074
	trans = btrfs_start_transaction(root->fs_info->tree_root, 0);
4075
	BUG_ON(IS_ERR(trans));
4076 4077 4078 4079 4080 4081 4082 4083 4084 4085 4086 4087 4088 4089

	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);
	BUG_ON(ret);

	ret = btrfs_end_transaction(trans, root->fs_info->tree_root);
	BUG_ON(ret);
	return 0;
}

4090 4091 4092 4093 4094 4095 4096 4097 4098 4099 4100 4101 4102 4103 4104 4105 4106 4107 4108 4109 4110 4111
/*
 * 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
4112
	path->reada = -1;
4113 4114 4115 4116 4117 4118 4119 4120 4121 4122 4123 4124 4125 4126 4127 4128 4129 4130 4131

	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]);
4132
		btrfs_release_path(path);
4133 4134 4135 4136 4137 4138 4139 4140 4141 4142 4143 4144 4145 4146 4147 4148 4149

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

		reloc_root = btrfs_read_fs_root_no_radix(root, &key);
		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)) {
4150 4151 4152 4153 4154 4155
				ret = PTR_ERR(fs_root);
				if (ret != -ENOENT) {
					err = ret;
					goto out;
				}
				mark_garbage_root(reloc_root);
4156 4157 4158 4159 4160 4161 4162 4163
			}
		}

		if (key.offset == 0)
			break;

		key.offset--;
	}
4164
	btrfs_release_path(path);
4165 4166 4167 4168

	if (list_empty(&reloc_roots))
		goto out;

4169
	rc = alloc_reloc_control();
4170 4171 4172 4173 4174 4175 4176 4177 4178
	if (!rc) {
		err = -ENOMEM;
		goto out;
	}

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

	set_reloc_control(rc);

4179
	trans = btrfs_join_transaction(rc->extent_root);
4180 4181 4182 4183 4184
	if (IS_ERR(trans)) {
		unset_reloc_control(rc);
		err = PTR_ERR(trans);
		goto out_free;
	}
4185 4186 4187

	rc->merge_reloc_tree = 1;

4188 4189 4190 4191 4192 4193 4194 4195 4196 4197 4198 4199 4200 4201 4202 4203 4204 4205 4206 4207 4208 4209 4210 4211 4212
	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);
		BUG_ON(IS_ERR(fs_root));

		__add_reloc_root(reloc_root);
		fs_root->reloc_root = reloc_root;
	}

	btrfs_commit_transaction(trans, rc->extent_root);

	merge_reloc_roots(rc);

	unset_reloc_control(rc);

4213
	trans = btrfs_join_transaction(rc->extent_root);
4214 4215 4216 4217 4218
	if (IS_ERR(trans))
		err = PTR_ERR(trans);
	else
		btrfs_commit_transaction(trans, rc->extent_root);
out_free:
4219
	kfree(rc);
4220
out:
4221 4222 4223 4224 4225 4226 4227 4228 4229 4230 4231 4232 4233 4234 4235 4236
	while (!list_empty(&reloc_roots)) {
		reloc_root = list_entry(reloc_roots.next,
					struct btrfs_root, root_list);
		list_del(&reloc_root->root_list);
		free_extent_buffer(reloc_root->node);
		free_extent_buffer(reloc_root->commit_root);
		kfree(reloc_root);
	}
	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);
4237
		else
4238
			err = btrfs_orphan_cleanup(fs_root);
4239 4240 4241 4242 4243 4244 4245 4246 4247 4248 4249 4250 4251 4252 4253 4254 4255 4256 4257 4258 4259 4260 4261 4262 4263 4264
	}
	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_sector_sum *sector_sum;
	struct btrfs_ordered_extent *ordered;
	struct btrfs_root *root = BTRFS_I(inode)->root;
	size_t offset;
	int ret;
	u64 disk_bytenr;
	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
4265
				       disk_bytenr + len - 1, &list, 0);
4266 4267 4268 4269 4270 4271 4272 4273 4274 4275 4276 4277 4278 4279 4280 4281 4282 4283

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

		sector_sum = sums->sums;
		sums->bytenr = ordered->start;

		offset = 0;
		while (offset < sums->len) {
			sector_sum->bytenr += ordered->start - disk_bytenr;
			sector_sum++;
			offset += root->sectorsize;
		}

		btrfs_add_ordered_sum(inode, ordered, sums);
	}
	btrfs_put_ordered_extent(ordered);
4284
	return ret;
4285
}
4286 4287 4288 4289 4290 4291 4292 4293 4294 4295 4296 4297 4298 4299 4300 4301 4302 4303 4304 4305 4306 4307 4308 4309 4310 4311 4312 4313 4314 4315 4316 4317 4318 4319 4320 4321 4322 4323 4324 4325 4326 4327 4328 4329 4330 4331 4332 4333 4334 4335 4336 4337 4338 4339 4340 4341 4342 4343 4344 4345 4346 4347 4348 4349 4350 4351 4352 4353 4354 4355 4356 4357 4358 4359 4360 4361 4362 4363 4364 4365 4366 4367 4368 4369 4370 4371 4372 4373 4374 4375 4376 4377 4378 4379 4380 4381 4382 4383 4384 4385 4386 4387 4388 4389 4390 4391 4392 4393 4394 4395 4396 4397 4398 4399 4400 4401 4402 4403 4404 4405 4406 4407 4408 4409 4410 4411 4412

void btrfs_reloc_cow_block(struct btrfs_trans_handle *trans,
			   struct btrfs_root *root, struct extent_buffer *buf,
			   struct extent_buffer *cow)
{
	struct reloc_control *rc;
	struct backref_node *node;
	int first_cow = 0;
	int level;
	int ret;

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

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

	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;
	}

	if (level == 0 && first_cow && rc->stage == UPDATE_DATA_PTRS) {
		ret = replace_file_extents(trans, rc, root, cow);
		BUG_ON(ret);
	}
}

/*
 * 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
 */
void btrfs_reloc_post_snapshot(struct btrfs_trans_handle *trans,
			       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)
		return;

	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);
		BUG_ON(ret);
	}

	new_root = pending->snap;
	reloc_root = create_reloc_root(trans, root->reloc_root,
				       new_root->root_key.objectid);

	__add_reloc_root(reloc_root);
	new_root->reloc_root = reloc_root;

	if (rc->create_reloc_tree) {
		ret = clone_backref_node(trans, rc, root, reloc_root);
		BUG_ON(ret);
	}
}