relocation.c 89.1 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>
#include "ctree.h"
#include "disk-io.h"
#include "transaction.h"
#include "volumes.h"
#include "locking.h"
#include "btrfs_inode.h"
#include "async-thread.h"

/*
 * 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;
	/* objectid tree block owner */
	u64 owner;
	/* 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;
	/* 1 if the block is root of old snapshot */
	unsigned int old_root:1;
	/* 1 if no child blocks in the cache */
	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;
};

/*
 * present a block pointer in the backref cache
 */
struct backref_edge {
	struct list_head list[2];
	struct backref_node *node[2];
	u64 blockptr;
};

#define LOWER	0
#define UPPER	1

struct backref_cache {
	/* red black tree of all backref nodes in the cache */
	struct rb_root rb_root;
	/* list of backref nodes with no child block in the cache */
	struct list_head pending[BTRFS_MAX_LEVEL];
	spinlock_t lock;
};

/*
 * 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;
};

/* inode vector */
#define INODEVEC_SIZE 16

struct inodevec {
	struct list_head list;
	struct inode *inode[INODEVEC_SIZE];
	int nr;
};

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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;
	struct btrfs_workers workers;
	/* 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;
	u64 search_start;
	u64 extents_found;
	u64 extents_skipped;
	int stage;
	int create_reloc_root;
	unsigned int found_file_extent:1;
	unsigned int found_old_snapshot:1;
};

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

/*
 * merge reloc tree to corresponding fs tree in worker threads
 */
struct async_merge {
	struct btrfs_work work;
	struct reloc_control *rc;
	struct btrfs_root *root;
	struct completion *done;
	atomic_t *num_pending;
};

static void mapping_tree_init(struct mapping_tree *tree)
{
	tree->rb_root.rb_node = NULL;
	spin_lock_init(&tree->lock);
}

static void backref_cache_init(struct backref_cache *cache)
{
	int i;
	cache->rb_root.rb_node = NULL;
	for (i = 0; i < BTRFS_MAX_LEVEL; i++)
		INIT_LIST_HEAD(&cache->pending[i]);
	spin_lock_init(&cache->lock);
}

static void backref_node_init(struct backref_node *node)
{
	memset(node, 0, sizeof(*node));
	INIT_LIST_HEAD(&node->upper);
	INIT_LIST_HEAD(&node->lower);
	RB_CLEAR_NODE(&node->rb_node);
}

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];
	}
	*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;
}

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

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

	drop_node_buffer(node);
	list_del(&node->lower);

	rb_erase(&node->rb_node, &tree->rb_root);
	kfree(node);
}

/*
 * 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;

	BUG_ON(!node->lowest);
	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]);
		kfree(edge);
		/*
		 * add the node to pending list if no other
		 * child block cached.
		 */
		if (list_empty(&upper->lower)) {
			list_add_tail(&upper->lower,
				      &cache->pending[upper->level]);
			upper->lowest = 1;
		}
	}
	drop_backref_node(cache, node);
}

/*
 * 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.
 */
static struct backref_node *build_backref_tree(struct reloc_control *rc,
					       struct backref_cache *cache,
					       struct btrfs_key *node_key,
					       int level, u64 bytenr)
{
	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);
	int ret;
	int err = 0;

	path1 = btrfs_alloc_path();
	path2 = btrfs_alloc_path();
	if (!path1 || !path2) {
		err = -ENOMEM;
		goto out;
	}

	node = kmalloc(sizeof(*node), GFP_NOFS);
	if (!node) {
		err = -ENOMEM;
		goto out;
	}

	backref_node_init(node);
	node->bytenr = bytenr;
	node->owner = 0;
	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)) {
		/*
		 * the backref was added previously when processsing
		 * 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) {
			if (key.objectid == key.offset &&
			    key.type == BTRFS_EXTENT_REF_V0_KEY) {
				struct btrfs_extent_ref_v0 *ref0;
				ref0 = btrfs_item_ptr(eb, path1->slots[0],
						struct btrfs_extent_ref_v0);
				root = find_tree_root(rc, eb, ref0);
				if (root)
					cur->root = root;
				else
					cur->old_root = 1;
				break;
			}
#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;
			}

			edge = kzalloc(sizeof(*edge), GFP_NOFS);
			if (!edge) {
				err = -ENOMEM;
				goto out;
			}
			rb_node = tree_search(&cache->rb_root, key.offset);
			if (!rb_node) {
				upper = kmalloc(sizeof(*upper), GFP_NOFS);
				if (!upper) {
					kfree(edge);
					err = -ENOMEM;
					goto out;
				}
				backref_node_init(upper);
				upper->bytenr = key.offset;
				upper->owner = 0;
				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);
				INIT_LIST_HEAD(&edge->list[UPPER]);
			}
			list_add(&edge->list[LOWER], &cur->upper);
			edge->node[UPPER] = upper;
			edge->node[LOWER] = cur;

			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;
		}

		if (btrfs_root_level(&root->root_item) == cur->level) {
			/* tree root */
			BUG_ON(btrfs_root_bytenr(&root->root_item) !=
			       cur->bytenr);
			cur->root = root;
			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;
		}
682 683
		if (ret > 0 && path2->slots[level] > 0)
			path2->slots[level]--;
684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985 986 987 988 989 990 991 992 993 994 995 996 997 998 999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 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 1081 1082 1083 1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 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 1163 1164 1165 1166 1167 1168 1169 1170 1171 1172 1173 1174 1175 1176 1177 1178 1179 1180 1181 1182 1183 1184 1185 1186 1187 1188 1189 1190 1191 1192 1193 1194 1195 1196 1197 1198 1199 1200 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 1261 1262 1263 1264 1265 1266 1267 1268 1269 1270 1271 1272 1273 1274 1275 1276 1277 1278 1279 1280 1281 1282 1283 1284 1285 1286 1287 1288 1289 1290 1291 1292 1293 1294 1295 1296 1297 1298 1299 1300 1301 1302 1303 1304 1305 1306 1307 1308 1309 1310 1311 1312 1313 1314 1315 1316 1317 1318 1319 1320 1321 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 1353 1354 1355 1356 1357 1358 1359 1360 1361 1362 1363 1364 1365 1366 1367 1368 1369 1370 1371 1372 1373 1374 1375 1376 1377 1378 1379 1380 1381 1382 1383 1384 1385 1386 1387 1388 1389 1390 1391 1392 1393 1394 1395 1396 1397 1398 1399 1400 1401 1402 1403 1404 1405 1406 1407 1408 1409 1410 1411 1412 1413 1414 1415 1416 1417 1418 1419 1420 1421 1422 1423 1424 1425 1426 1427 1428 1429 1430 1431 1432 1433 1434 1435 1436 1437 1438 1439 1440 1441 1442 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 1478 1479 1480 1481 1482 1483 1484 1485 1486 1487 1488 1489 1490 1491 1492 1493 1494 1495 1496 1497 1498 1499 1500 1501 1502 1503 1504 1505 1506 1507 1508 1509 1510 1511 1512 1513 1514 1515 1516 1517 1518 1519 1520 1521 1522 1523 1524 1525 1526 1527 1528 1529 1530 1531 1532 1533 1534 1535 1536 1537 1538 1539 1540 1541 1542 1543 1544 1545 1546 1547 1548 1549 1550 1551 1552 1553 1554 1555 1556 1557 1558 1559 1560 1561 1562 1563

		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);
				lower->root = root;
				break;
			}

			edge = kzalloc(sizeof(*edge), GFP_NOFS);
			if (!edge) {
				err = -ENOMEM;
				goto out;
			}

			eb = path2->nodes[level];
			rb_node = tree_search(&cache->rb_root, eb->start);
			if (!rb_node) {
				upper = kmalloc(sizeof(*upper), GFP_NOFS);
				if (!upper) {
					kfree(edge);
					err = -ENOMEM;
					goto out;
				}
				backref_node_init(upper);
				upper->bytenr = eb->start;
				upper->owner = btrfs_header_owner(eb);
				upper->level = lower->level + 1;

				/*
				 * 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]);
			}
			list_add_tail(&edge->list[LOWER], &lower->upper);
			edge->node[UPPER] = upper;
			edge->node[LOWER] = lower;

			if (rb_node)
				break;
			lower = upper;
			upper = NULL;
		}
		btrfs_release_path(root, path2);
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]++;
	}
	btrfs_release_path(rc->extent_root, path1);

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

	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];

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

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

		list_for_each_entry(edge, &upper->upper, list[LOWER])
			list_add_tail(&edge->list[UPPER], &list);
	}
out:
	btrfs_free_path(path1);
	btrfs_free_path(path2);
	if (err) {
		INIT_LIST_HEAD(&list);
		upper = node;
		while (upper) {
			if (RB_EMPTY_NODE(&upper->rb_node)) {
				list_splice_tail(&upper->upper, &list);
				kfree(upper);
			}

			if (list_empty(&list))
				break;

			edge = list_entry(list.next, struct backref_edge,
					  list[LOWER]);
			upper = edge->node[UPPER];
			kfree(edge);
		}
		return ERR_PTR(err);
	}
	return node;
}

/*
 * 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;
}

/*
 * 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 extent_buffer *eb;
	struct btrfs_root_item *root_item;
	struct btrfs_key root_key;
	int ret;

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

	if (!root->fs_info->reloc_ctl ||
	    !root->fs_info->reloc_ctl->create_reloc_root ||
	    root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID)
		return 0;

	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;
	root_key.offset = root->root_key.objectid;

	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);
	memcpy(root_item, &root->root_item, sizeof(*root_item));
	btrfs_set_root_refs(root_item, 1);
	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);
	memset(&root_item->drop_progress, 0, sizeof(struct btrfs_disk_key));
	root_item->drop_level = 0;

	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;

	__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)
		return 0;

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

	if (btrfs_root_refs(root_item) == 0) {
		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);
	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);

		if (objectid < entry->vfs_inode.i_ino)
			node = node->rb_left;
		else if (objectid > entry->vfs_inode.i_ino)
			node = node->rb_right;
		else
			break;
	}
	if (!node) {
		while (prev) {
			entry = rb_entry(prev, struct btrfs_inode, rb_node);
			if (objectid <= entry->vfs_inode.i_ino) {
				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;
		}

		objectid = entry->vfs_inode.i_ino + 1;
		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;
	ret = btrfs_lookup_file_extent(NULL, root, path, reloc_inode->i_ino,
				       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;
	}

	if (new_bytenr)
		*new_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
	ret = 0;
out:
	btrfs_free_path(path);
	return ret;
}

/*
 * update file extent items in the tree leaf to point to
 * the new locations.
 */
static int replace_file_extents(struct btrfs_trans_handle *trans,
				struct reloc_control *rc,
				struct btrfs_root *root,
				struct extent_buffer *leaf,
				struct list_head *inode_list)
{
	struct btrfs_key key;
	struct btrfs_file_extent_item *fi;
	struct inode *inode = NULL;
	struct inodevec *ivec = NULL;
	u64 parent;
	u64 bytenr;
	u64 new_bytenr;
	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 (!ivec || ivec->nr == INODEVEC_SIZE) {
				ivec = kmalloc(sizeof(*ivec), GFP_NOFS);
				BUG_ON(!ivec);
				ivec->nr = 0;
				list_add_tail(&ivec->list, inode_list);
			}
			if (first) {
				inode = find_next_inode(root, key.objectid);
				if (inode)
					ivec->inode[ivec->nr++] = inode;
				first = 0;
			} else if (inode && inode->i_ino < key.objectid) {
				inode = find_next_inode(root, key.objectid);
				if (inode)
					ivec->inode[ivec->nr++] = inode;
			}
			if (inode && inode->i_ino == key.objectid) {
				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);
		if (ret > 0)
			continue;
		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);
	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.
 */
static 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,
			struct extent_buffer **leaf,
			int lowest_level, int max_level)
{
	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;
	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);
	BUG_ON(lowest_level > 1 && leaf);

	last_snapshot = btrfs_root_last_snapshot(&src->root_item);

	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;
	}

	ret = btrfs_cow_block(trans, dest, eb, NULL, 0, &eb);
	BUG_ON(ret);
	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)) {
			if (level <= lowest_level && !leaf) {
				ret = 0;
				break;
			}

			eb = read_tree_block(dest, old_bytenr, blocksize,
					     old_ptr_gen);
			btrfs_tree_lock(eb);
			ret = btrfs_cow_block(trans, dest, eb, parent,
					      slot, &eb);
			BUG_ON(ret);
			btrfs_set_lock_blocking(eb);

			if (level <= lowest_level) {
				*leaf = eb;
				ret = 0;
				break;
			}

			btrfs_tree_unlock(parent);
			free_extent_buffer(parent);

			parent = eb;
			continue;
		}

		btrfs_node_key_to_cpu(path->nodes[level], &key,
				      path->slots[level]);
		btrfs_release_path(src, path);

		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;

	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;

		if (inode->i_ino > max_key->objectid) {
			iput(inode);
			break;
		}

		objectid = inode->i_ino + 1;
		if (!S_ISREG(inode->i_mode))
			continue;

		if (unlikely(min_key->objectid == inode->i_ino)) {
			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;
		}

		if (unlikely(max_key->objectid == inode->i_ino)) {
			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;
}

1564 1565 1566 1567 1568 1569 1570 1571 1572 1573 1574 1575 1576 1577
static void put_inodes(struct list_head *list)
{
	struct inodevec *ivec;
	while (!list_empty(list)) {
		ivec = list_entry(list->next, struct inodevec, list);
		list_del(&ivec->list);
		while (ivec->nr > 0) {
			ivec->nr--;
			iput(ivec->inode[ivec->nr]);
		}
		kfree(ivec);
	}
}

1578 1579 1580 1581 1582 1583 1584 1585 1586 1587 1588 1589 1590 1591 1592 1593 1594 1595 1596 1597 1598 1599 1600 1601 1602 1603 1604 1605 1606 1607 1608 1609 1610 1611 1612 1613 1614 1615 1616 1617 1618 1619 1620 1621 1622 1623 1624 1625 1626 1627 1628 1629 1630 1631 1632 1633 1634 1635 1636
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;
	struct extent_buffer *leaf = NULL;
	unsigned long nr;
	int level;
	int max_level;
	int replaced = 0;
	int ret;
	int err = 0;

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

	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);
1637
		path->lowest_level = 0;
1638 1639 1640 1641 1642 1643 1644 1645 1646 1647 1648 1649 1650 1651 1652 1653 1654 1655 1656 1657 1658 1659 1660 1661 1662 1663 1664 1665 1666 1667 1668 1669 1670 1671 1672 1673 1674 1675 1676 1677 1678 1679 1680 1681 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 1725 1726 1727 1728 1729 1730 1731 1732 1733 1734 1735 1736 1737 1738 1739
		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);
	}

	if (level == 0 && rc->stage == UPDATE_DATA_PTRS) {
		trans = btrfs_start_transaction(root, 1);

		leaf = path->nodes[0];
		btrfs_item_key_to_cpu(leaf, &key, 0);
		btrfs_release_path(reloc_root, path);

		ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
		if (ret < 0) {
			err = ret;
			goto out;
		}

		leaf = path->nodes[0];
		btrfs_unlock_up_safe(path, 1);
		ret = replace_file_extents(trans, rc, root, leaf,
					   &inode_list);
		if (ret < 0)
			err = ret;
		goto out;
	}

	memset(&next_key, 0, sizeof(next_key));

	while (1) {
		leaf = NULL;
		replaced = 0;
		trans = btrfs_start_transaction(root, 1);
		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 if (level == 1 && rc->stage == UPDATE_DATA_PTRS) {
			ret = replace_path(trans, root, reloc_root,
					   path, &next_key, &leaf,
					   level, max_level);
		} else {
			ret = replace_path(trans, root, reloc_root,
					   path, &next_key, NULL,
					   level, max_level);
		}
		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;
		} else if (leaf) {
			/*
			 * no block got replaced, try replacing file extents
			 */
			btrfs_item_key_to_cpu(leaf, &key, 0);
			ret = replace_file_extents(trans, rc, root, leaf,
						   &inode_list);
			btrfs_tree_unlock(leaf);
			free_extent_buffer(leaf);
			BUG_ON(ret < 0);
		}

		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;
		btrfs_end_transaction(trans, root);

		btrfs_btree_balance_dirty(root, nr);

1740 1741 1742 1743 1744
		/*
		 * put inodes outside transaction, otherwise we may deadlock.
		 */
		put_inodes(&inode_list);

1745 1746 1747 1748 1749 1750 1751 1752 1753 1754 1755 1756 1757 1758 1759 1760 1761 1762 1763 1764 1765 1766 1767 1768 1769 1770 1771 1772 1773
		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);
	}

	nr = trans->blocks_used;
	btrfs_end_transaction(trans, root);

	btrfs_btree_balance_dirty(root, nr);

1774
	put_inodes(&inode_list);
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

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

	return err;
}

/*
 * callback for the work threads.
 * this function merges reloc tree with corresponding fs tree,
 * and then drops the reloc tree.
 */
static void merge_func(struct btrfs_work *work)
{
	struct btrfs_trans_handle *trans;
	struct btrfs_root *root;
	struct btrfs_root *reloc_root;
	struct async_merge *async;

	async = container_of(work, struct async_merge, work);
	reloc_root = async->root;

	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);

		merge_reloc_root(async->rc, root);

		trans = btrfs_start_transaction(root, 1);
		btrfs_update_reloc_root(trans, root);
		btrfs_end_transaction(trans, root);
	}

1810
	btrfs_drop_snapshot(reloc_root, 0);
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 1901 1902 1903 1904 1905 1906 1907 1908 1909 1910 1911 1912 1913 1914 1915 1916 1917 1918 1919 1920 1921 1922 1923 1924 1925 1926 1927 1928 1929 1930 1931 1932 1933 1934 1935 1936 1937 1938 1939 1940 1941 1942 1943 1944 1945 1946 1947 1948 1949 1950 1951 1952 1953 1954 1955 1956 1957 1958 1959 1960 1961 1962 1963 1964 1965 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023 2024 2025 2026 2027 2028 2029 2030 2031 2032 2033 2034 2035 2036 2037 2038 2039 2040 2041 2042 2043 2044 2045 2046 2047 2048 2049 2050 2051 2052 2053 2054 2055 2056 2057 2058 2059 2060 2061 2062 2063 2064 2065 2066 2067 2068 2069 2070 2071 2072 2073 2074 2075 2076 2077 2078 2079 2080 2081 2082 2083 2084 2085 2086 2087 2088 2089 2090 2091 2092 2093 2094 2095 2096 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 2122 2123 2124 2125 2126 2127 2128 2129 2130 2131 2132 2133 2134 2135 2136 2137 2138 2139 2140 2141 2142 2143 2144 2145 2146 2147 2148 2149 2150 2151 2152 2153 2154 2155 2156 2157 2158 2159 2160 2161 2162 2163 2164 2165 2166 2167 2168 2169 2170 2171 2172 2173 2174 2175 2176 2177 2178 2179 2180 2181 2182 2183 2184 2185 2186 2187 2188 2189 2190 2191 2192 2193 2194 2195 2196 2197 2198

	if (atomic_dec_and_test(async->num_pending))
		complete(async->done);

	kfree(async);
}

static int merge_reloc_roots(struct reloc_control *rc)
{
	struct async_merge *async;
	struct btrfs_root *root;
	struct completion done;
	atomic_t num_pending;

	init_completion(&done);
	atomic_set(&num_pending, 1);

	while (!list_empty(&rc->reloc_roots)) {
		root = list_entry(rc->reloc_roots.next,
				  struct btrfs_root, root_list);
		list_del_init(&root->root_list);

		async = kmalloc(sizeof(*async), GFP_NOFS);
		BUG_ON(!async);
		async->work.func = merge_func;
		async->work.flags = 0;
		async->rc = rc;
		async->root = root;
		async->done = &done;
		async->num_pending = &num_pending;
		atomic_inc(&num_pending);
		btrfs_queue_worker(&rc->workers, &async->work);
	}

	if (!atomic_dec_and_test(&num_pending))
		wait_for_completion(&done);

	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);
}

/*
 * select one tree from trees that references the block.
 * for blocks in refernce counted trees, we preper reloc tree.
 * if no reloc tree found and reloc_only is true, NULL is returned.
 */
static struct btrfs_root *__select_one_root(struct btrfs_trans_handle *trans,
					    struct backref_node *node,
					    struct backref_edge *edges[],
					    int *nr, int reloc_only)
{
	struct backref_node *next;
	struct btrfs_root *root;
	int index;
	int loop = 0;
again:
	index = 0;
	next = node;
	while (1) {
		cond_resched();
		next = walk_up_backref(next, edges, &index);
		root = next->root;
		if (!root) {
			BUG_ON(!node->old_root);
			goto skip;
		}

		/* no other choice for non-refernce counted tree */
		if (!root->ref_cows) {
			BUG_ON(reloc_only);
			break;
		}

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

		if (loop) {
			btrfs_record_root_in_trans(trans, root);
			break;
		}

		if (reloc_only || next != node) {
			if (!root->reloc_root)
				btrfs_record_root_in_trans(trans, root);
			root = root->reloc_root;
			/*
			 * if the reloc tree was created in current
			 * transation, there is no node in backref tree
			 * corresponds to the root of the reloc tree.
			 */
			if (btrfs_root_last_snapshot(&root->root_item) ==
			    trans->transid - 1)
				break;
		}
skip:
		root = NULL;
		next = walk_down_backref(edges, &index);
		if (!next || next->level <= node->level)
			break;
	}

	if (!root && !loop && !reloc_only) {
		loop = 1;
		goto again;
	}

	if (root)
		*nr = index;
	else
		*nr = 0;

	return root;
}

static noinline_for_stack
struct btrfs_root *select_one_root(struct btrfs_trans_handle *trans,
				   struct backref_node *node)
{
	struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
	int nr;
	return __select_one_root(trans, node, edges, &nr, 0);
}

static noinline_for_stack
struct btrfs_root *select_reloc_root(struct btrfs_trans_handle *trans,
				     struct backref_node *node,
				     struct backref_edge *edges[], int *nr)
{
	return __select_one_root(trans, node, edges, nr, 1);
}

static void grab_path_buffers(struct btrfs_path *path,
			      struct backref_node *node,
			      struct backref_edge *edges[], int nr)
{
	int i = 0;
	while (1) {
		drop_node_buffer(node);
		node->eb = path->nodes[node->level];
		BUG_ON(!node->eb);
		if (path->locks[node->level])
			node->locked = 1;
		path->nodes[node->level] = NULL;
		path->locks[node->level] = 0;

		if (i >= nr)
			break;

		edges[i]->blockptr = node->eb->start;
		node = edges[i]->node[UPPER];
		i++;
	}
}

/*
 * 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,
			 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;
	list_for_each_entry(edge, &node->upper, list[LOWER]) {
		cond_resched();
		if (node->eb && node->eb->start == edge->blockptr)
			continue;

		upper = edge->node[UPPER];
		root = select_reloc_root(trans, upper, edges, &nr);
		if (!root)
			continue;

		if (upper->eb && !upper->locked)
			drop_node_buffer(upper);

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

			slot = path->slots[upper->level];

			btrfs_unlock_up_safe(path, upper->level + 1);
			grab_path_buffers(path, upper, edges, nr);

			btrfs_release_path(NULL, path);
		} else {
			ret = btrfs_bin_search(upper->eb, key, upper->level,
					       &slot);
			BUG_ON(ret);
		}

		bytenr = btrfs_node_blockptr(upper->eb, slot);
		if (!lowest) {
			if (node->eb->start == bytenr) {
				btrfs_tree_unlock(upper->eb);
				upper->locked = 0;
				continue;
			}
		} else {
			BUG_ON(node->bytenr != bytenr);
		}

		blocksize = btrfs_level_size(root, node->level);
		generation = btrfs_node_ptr_generation(upper->eb, slot);
		eb = read_tree_block(root, bytenr, blocksize, generation);
		btrfs_tree_lock(eb);
		btrfs_set_lock_blocking(eb);

		if (!node->eb) {
			ret = btrfs_cow_block(trans, root, eb, upper->eb,
					      slot, &eb);
			if (ret < 0) {
				err = ret;
				break;
			}
			btrfs_set_lock_blocking(eb);
			node->eb = eb;
			node->locked = 1;
		} 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);
		}
		if (!lowest) {
			btrfs_tree_unlock(upper->eb);
			upper->locked = 0;
		}
	}
	path->lowest_level = 0;
	return err;
}

static int link_to_upper(struct btrfs_trans_handle *trans,
			 struct backref_node *node,
			 struct btrfs_path *path)
{
	struct btrfs_key key;
	if (!node->eb || list_empty(&node->upper))
		return 0;

	btrfs_node_key_to_cpu(node->eb, &key, 0);
	return do_relocation(trans, node, &key, path, 0);
}

static int finish_pending_nodes(struct btrfs_trans_handle *trans,
				struct backref_cache *cache,
				struct btrfs_path *path)
{
	struct backref_node *node;
	int level;
	int ret;
	int err = 0;

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

			ret = link_to_upper(trans, node, path);
			if (ret < 0)
				err = ret;
			/*
			 * this remove the node from the pending list and
			 * may add some other nodes to the level + 1
			 * pending list
			 */
			remove_backref_node(cache, node);
		}
	}
	BUG_ON(!RB_EMPTY_ROOT(&cache->rb_root));
	return err;
}

static void mark_block_processed(struct reloc_control *rc,
				 struct backref_node *node)
{
	u32 blocksize;
	if (node->level == 0 ||
	    in_block_group(node->bytenr, rc->block_group)) {
		blocksize = btrfs_level_size(rc->extent_root, node->level);
		set_extent_bits(&rc->processed_blocks, node->bytenr,
				node->bytenr + blocksize - 1, EXTENT_DIRTY,
				GFP_NOFS);
	}
	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;

			mark_block_processed(rc, next);

			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);
	}
}

static int tree_block_processed(u64 bytenr, u32 blocksize,
				struct reloc_control *rc)
{
	if (test_range_bit(&rc->processed_blocks, bytenr,
2199
			   bytenr + blocksize - 1, EXTENT_DIRTY, 1, NULL))
2200 2201 2202 2203 2204 2205 2206 2207 2208 2209 2210 2211 2212 2213 2214 2215 2216 2217 2218 2219 2220 2221 2222 2223 2224 2225 2226 2227 2228 2229 2230 2231 2232 2233 2234 2235 2236 2237 2238 2239 2240 2241 2242 2243 2244 2245 2246 2247 2248 2249 2250 2251 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 2282 2283 2284 2285 2286 2287 2288 2289 2290 2291 2292 2293 2294 2295 2296 2297 2298 2299 2300 2301 2302 2303 2304 2305 2306 2307 2308 2309 2310 2311 2312 2313 2314 2315 2316 2317 2318 2319 2320 2321 2322 2323 2324 2325 2326 2327 2328 2329 2330 2331 2332 2333 2334 2335 2336 2337 2338 2339 2340 2341 2342 2343 2344 2345 2346 2347 2348 2349 2350 2351 2352 2353 2354 2355 2356 2357 2358 2359 2360 2361 2362 2363 2364 2365 2366 2367 2368 2369 2370 2371 2372 2373 2374 2375 2376 2377 2378 2379 2380 2381 2382 2383 2384 2385 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 2415 2416 2417 2418 2419 2420 2421 2422 2423 2424 2425 2426 2427 2428 2429 2430 2431 2432 2433 2434 2435 2436 2437 2438 2439 2440 2441 2442 2443 2444 2445 2446 2447 2448 2449 2450 2451 2452 2453 2454 2455 2456 2457 2458 2459 2460 2461 2462 2463 2464 2465 2466 2467 2468 2469 2470 2471 2472 2473 2474 2475 2476 2477 2478 2479 2480 2481 2482 2483 2484 2485 2486 2487 2488 2489 2490 2491 2492 2493 2494 2495 2496 2497 2498 2499 2500 2501 2502 2503 2504 2505 2506 2507 2508 2509 2510 2511 2512 2513 2514 2515 2516 2517 2518 2519 2520 2521 2522 2523 2524 2525 2526 2527 2528 2529 2530 2531 2532 2533 2534 2535 2536 2537 2538 2539 2540 2541 2542 2543 2544 2545 2546 2547
		return 1;
	return 0;
}

/*
 * check if there are any file extent pointers in the leaf point to
 * data require processing
 */
static int check_file_extents(struct reloc_control *rc,
			      u64 bytenr, u32 blocksize, u64 ptr_gen)
{
	struct btrfs_key found_key;
	struct btrfs_file_extent_item *fi;
	struct extent_buffer *leaf;
	u32 nritems;
	int i;
	int ret = 0;

	leaf = read_tree_block(rc->extent_root, bytenr, blocksize, ptr_gen);

	nritems = btrfs_header_nritems(leaf);
	for (i = 0; i < nritems; i++) {
		cond_resched();
		btrfs_item_key_to_cpu(leaf, &found_key, i);
		if (found_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);
		if (bytenr == 0)
			continue;
		if (in_block_group(bytenr, rc->block_group)) {
			ret = 1;
			break;
		}
	}
	free_extent_buffer(leaf);
	return ret;
}

/*
 * scan child blocks of a given block to find blocks require processing
 */
static int add_child_blocks(struct btrfs_trans_handle *trans,
			    struct reloc_control *rc,
			    struct backref_node *node,
			    struct rb_root *blocks)
{
	struct tree_block *block;
	struct rb_node *rb_node;
	u64 bytenr;
	u64 ptr_gen;
	u32 blocksize;
	u32 nritems;
	int i;
	int err = 0;

	nritems = btrfs_header_nritems(node->eb);
	blocksize = btrfs_level_size(rc->extent_root, node->level - 1);
	for (i = 0; i < nritems; i++) {
		cond_resched();
		bytenr = btrfs_node_blockptr(node->eb, i);
		ptr_gen = btrfs_node_ptr_generation(node->eb, i);
		if (ptr_gen == trans->transid)
			continue;
		if (!in_block_group(bytenr, rc->block_group) &&
		    (node->level > 1 || rc->stage == MOVE_DATA_EXTENTS))
			continue;
		if (tree_block_processed(bytenr, blocksize, rc))
			continue;

		readahead_tree_block(rc->extent_root,
				     bytenr, blocksize, ptr_gen);
	}

	for (i = 0; i < nritems; i++) {
		cond_resched();
		bytenr = btrfs_node_blockptr(node->eb, i);
		ptr_gen = btrfs_node_ptr_generation(node->eb, i);
		if (ptr_gen == trans->transid)
			continue;
		if (!in_block_group(bytenr, rc->block_group) &&
		    (node->level > 1 || rc->stage == MOVE_DATA_EXTENTS))
			continue;
		if (tree_block_processed(bytenr, blocksize, rc))
			continue;
		if (!in_block_group(bytenr, rc->block_group) &&
		    !check_file_extents(rc, bytenr, blocksize, ptr_gen))
			continue;

		block = kmalloc(sizeof(*block), GFP_NOFS);
		if (!block) {
			err = -ENOMEM;
			break;
		}
		block->bytenr = bytenr;
		btrfs_node_key_to_cpu(node->eb, &block->key, i);
		block->level = node->level - 1;
		block->key_ready = 1;
		rb_node = tree_insert(blocks, block->bytenr, &block->rb_node);
		BUG_ON(rb_node);
	}
	if (err)
		free_block_list(blocks);
	return err;
}

/*
 * find adjacent blocks require processing
 */
static noinline_for_stack
int add_adjacent_blocks(struct btrfs_trans_handle *trans,
			struct reloc_control *rc,
			struct backref_cache *cache,
			struct rb_root *blocks, int level,
			struct backref_node **upper)
{
	struct backref_node *node;
	int ret = 0;

	WARN_ON(!list_empty(&cache->pending[level]));

	if (list_empty(&cache->pending[level + 1]))
		return 1;

	node = list_entry(cache->pending[level + 1].next,
			  struct backref_node, lower);
	if (node->eb)
		ret = add_child_blocks(trans, rc, node, blocks);

	*upper = node;
	return ret;
}

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);
	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;
	int ret;

	root = select_one_root(trans, node);
	if (unlikely(!root)) {
		rc->found_old_snapshot = 1;
		update_processed_blocks(rc, node);
		return 0;
	}

	if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) {
		ret = do_relocation(trans, node, key, path, 1);
		if (ret < 0)
			goto out;
		if (node->level == 0 && rc->stage == UPDATE_DATA_PTRS) {
			ret = replace_file_extents(trans, rc, root,
						   node->eb, NULL);
			if (ret < 0)
				goto out;
		}
		drop_node_buffer(node);
	} else if (!root->ref_cows) {
		path->lowest_level = node->level;
		ret = btrfs_search_slot(trans, root, key, path, 0, 1);
		btrfs_release_path(root, path);
		if (ret < 0)
			goto out;
	} else if (root != node->root) {
		WARN_ON(node->level > 0 || rc->stage != UPDATE_DATA_PTRS);
	}

	update_processed_blocks(rc, node);
	ret = 0;
out:
	drop_node_buffer(node);
	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_cache *cache;
	struct backref_node *node;
	struct btrfs_path *path;
	struct tree_block *block;
	struct rb_node *rb_node;
	int level = -1;
	int ret;
	int err = 0;

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

	cache = kmalloc(sizeof(*cache), GFP_NOFS);
	if (!cache) {
		btrfs_free_path(path);
		return -ENOMEM;
	}

	backref_cache_init(cache);

	rb_node = rb_first(blocks);
	while (rb_node) {
		block = rb_entry(rb_node, struct tree_block, rb_node);
		if (level == -1)
			level = block->level;
		else
			BUG_ON(level != block->level);
		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);

		node = build_backref_tree(rc, cache, &block->key,
					  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) {
			err = ret;
			goto out;
		}
		remove_backref_node(cache, node);
		rb_node = rb_next(rb_node);
	}

	if (level > 0)
		goto out;

	free_block_list(blocks);

	/*
	 * now backrefs of some upper level tree blocks have been cached,
	 * try relocating blocks referenced by these upper level blocks.
	 */
	while (1) {
		struct backref_node *upper = NULL;
		if (trans->transaction->in_commit ||
		    trans->transaction->delayed_refs.flushing)
			break;

		ret = add_adjacent_blocks(trans, rc, cache, blocks, level,
					  &upper);
		if (ret < 0)
			err = ret;
		if (ret != 0)
			break;

		rb_node = rb_first(blocks);
		while (rb_node) {
			block = rb_entry(rb_node, struct tree_block, rb_node);
			if (trans->transaction->in_commit ||
			    trans->transaction->delayed_refs.flushing)
				goto out;
			BUG_ON(!block->key_ready);
			node = build_backref_tree(rc, cache, &block->key,
						  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) {
				err = ret;
				goto out;
			}
			remove_backref_node(cache, node);
			rb_node = rb_next(rb_node);
		}
		free_block_list(blocks);

		if (upper) {
			ret = link_to_upper(trans, upper, path);
			if (ret < 0) {
				err = ret;
				break;
			}
			remove_backref_node(cache, upper);
		}
	}
out:
	free_block_list(blocks);

	ret = finish_pending_nodes(trans, cache, path);
	if (ret < 0)
		err = ret;

	kfree(cache);
	btrfs_free_path(path);
	return err;
}

static noinline_for_stack
2548 2549 2550 2551 2552 2553 2554 2555 2556 2557 2558 2559 2560 2561 2562 2563 2564 2565 2566 2567 2568 2569 2570 2571 2572 2573 2574 2575 2576 2577 2578 2579 2580 2581 2582 2583
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;

	em = alloc_extent_map(GFP_NOFS);
	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)
2584 2585 2586
{
	u64 page_start;
	u64 page_end;
2587 2588
	u64 offset = BTRFS_I(inode)->index_cnt;
	unsigned long index;
2589
	unsigned long last_index;
2590
	unsigned int dirty_page = 0;
2591 2592
	struct page *page;
	struct file_ra_state *ra;
2593
	int nr = 0;
2594 2595
	int ret = 0;

2596 2597 2598
	if (!cluster->nr)
		return 0;

2599 2600 2601 2602
	ra = kzalloc(sizeof(*ra), GFP_NOFS);
	if (!ra)
		return -ENOMEM;

2603 2604 2605
	index = (cluster->start - offset) >> PAGE_CACHE_SHIFT;
	last_index = (cluster->end - offset) >> PAGE_CACHE_SHIFT;

2606 2607
	mutex_lock(&inode->i_mutex);

2608 2609 2610
	i_size_write(inode, cluster->end + 1 - offset);
	ret = setup_extent_mapping(inode, cluster->start - offset,
				   cluster->end - offset, cluster->start);
2611 2612 2613 2614 2615
	if (ret)
		goto out_unlock;

	file_ra_state_init(ra, inode->i_mapping);

2616 2617 2618
	WARN_ON(cluster->start != cluster->boundary[0]);
	while (index <= last_index) {
		page = find_lock_page(inode->i_mapping, index);
2619
		if (!page) {
2620 2621 2622 2623 2624 2625 2626 2627
			page_cache_sync_readahead(inode->i_mapping,
						  ra, NULL, index,
						  last_index + 1 - index);
			page = grab_cache_page(inode->i_mapping, index);
			if (!page) {
				ret = -ENOMEM;
				goto out_unlock;
			}
2628
		}
2629 2630 2631 2632 2633 2634 2635

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

2636 2637 2638 2639 2640 2641 2642 2643 2644 2645 2646 2647 2648
		if (!PageUptodate(page)) {
			btrfs_readpage(NULL, page);
			lock_page(page);
			if (!PageUptodate(page)) {
				unlock_page(page);
				page_cache_release(page);
				ret = -EIO;
				goto out_unlock;
			}
		}

		page_start = (u64)page->index << PAGE_CACHE_SHIFT;
		page_end = page_start + PAGE_CACHE_SIZE - 1;
2649 2650 2651 2652

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

2653 2654
		set_page_extent_mapped(page);

2655 2656 2657 2658
		if (nr < cluster->nr &&
		    page_start + offset == cluster->boundary[nr]) {
			set_extent_bits(&BTRFS_I(inode)->io_tree,
					page_start, page_end,
2659
					EXTENT_BOUNDARY, GFP_NOFS);
2660 2661
			nr++;
		}
2662 2663 2664
		btrfs_set_extent_delalloc(inode, page_start, page_end);

		set_page_dirty(page);
2665
		dirty_page++;
2666

2667 2668
		unlock_extent(&BTRFS_I(inode)->io_tree,
			      page_start, page_end, GFP_NOFS);
2669 2670
		unlock_page(page);
		page_cache_release(page);
2671 2672 2673 2674 2675 2676 2677 2678 2679 2680 2681 2682

		index++;
		if (nr < cluster->nr &&
		    page_end + 1 + offset == cluster->boundary[nr]) {
			balance_dirty_pages_ratelimited_nr(inode->i_mapping,
							   dirty_page);
			dirty_page = 0;
		}
	}
	if (dirty_page) {
		balance_dirty_pages_ratelimited_nr(inode->i_mapping,
						   dirty_page);
2683
	}
2684
	WARN_ON(nr != cluster->nr);
2685 2686 2687 2688 2689 2690 2691
out_unlock:
	mutex_unlock(&inode->i_mutex);
	kfree(ra);
	return ret;
}

static noinline_for_stack
2692 2693
int relocate_data_extent(struct inode *inode, struct btrfs_key *extent_key,
			 struct file_extent_cluster *cluster)
2694
{
2695
	int ret;
2696

2697 2698 2699 2700 2701
	if (cluster->nr > 0 && extent_key->objectid != cluster->end + 1) {
		ret = relocate_file_extent_cluster(inode, cluster);
		if (ret)
			return ret;
		cluster->nr = 0;
2702 2703
	}

2704 2705 2706 2707 2708 2709 2710 2711 2712 2713 2714 2715 2716 2717 2718
	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;
2719 2720 2721 2722 2723 2724 2725 2726 2727 2728 2729 2730 2731 2732 2733 2734 2735 2736 2737 2738 2739 2740 2741 2742 2743 2744 2745 2746 2747 2748 2749 2750 2751 2752 2753 2754 2755 2756 2757 2758 2759 2760 2761 2762 2763 2764 2765 2766 2767 2768 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 2810 2811 2812 2813 2814 2815 2816 2817 2818 2819 2820 2821 2822 2823 2824 2825 2826 2827 2828 2829 2830 2831 2832 2833 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 2878 2879 2880 2881 2882 2883 2884 2885 2886 2887 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 2915 2916 2917 2918 2919 2920 2921 2922 2923 2924 2925 2926 2927 2928 2929 2930 2931 2932 2933 2934 2935 2936 2937 2938 2939 2940 2941 2942 2943 2944 2945 2946 2947 2948 2949 2950 2951 2952 2953 2954 2955 2956 2957 2958 2959 2960 2961 2962 2963 2964 2965 2966 2967 2968 2969 2970 2971 2972 2973 2974 2975 2976 2977 2978 2979 2980 2981 2982 2983 2984 2985 2986 2987 2988 2989 2990 2991 2992 2993 2994 2995 2996 2997 2998 2999 3000 3001 3002 3003 3004 3005 3006 3007 3008 3009 3010 3011 3012 3013 3014 3015 3016 3017 3018 3019 3020 3021 3022 3023 3024 3025 3026 3027 3028 3029 3030 3031 3032 3033 3034 3035 3036 3037 3038 3039 3040 3041 3042 3043 3044 3045 3046 3047 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 3127 3128 3129 3130 3131 3132 3133 3134 3135 3136 3137 3138 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 3210 3211 3212 3213 3214 3215 3216 3217 3218 3219 3220 3221 3222 3223 3224 3225 3226 3227 3228 3229 3230 3231 3232 3233 3234 3235 3236 3237 3238 3239 3240 3241 3242 3243 3244 3245 3246 3247 3248 3249 3250 3251 3252 3253 3254 3255 3256 3257 3258 3259 3260 3261 3262 3263
}

#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);
		BUG_ON(ref_owner >= BTRFS_MAX_LEVEL);
		level = (int)ref_owner;
		/* FIXME: get real generation */
		generation = 0;
#else
		BUG();
#endif
	}

	btrfs_release_path(rc->extent_root, path);

	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)
{
	struct btrfs_path *path;
	struct btrfs_extent_item *ei;
	struct btrfs_key key;
	u64 flags;
	int ret;

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

	path = btrfs_alloc_path();
	BUG_ON(!path);

	key.objectid = eb->start;
	key.type = BTRFS_EXTENT_ITEM_KEY;
	key.offset = eb->len;

	path->search_commit_root = 1;
	path->skip_locking = 1;
	ret = btrfs_search_slot(NULL, rc->extent_root,
				&key, path, 0, 0);
	BUG_ON(ret);

	ei = btrfs_item_ptr(path->nodes[0], path->slots[0],
			    struct btrfs_extent_item);
	flags = btrfs_extent_flags(path->nodes[0], ei);
	BUG_ON(!(flags & BTRFS_EXTENT_FLAG_TREE_BLOCK));
	if (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF)
		ret = 1;
	else
		ret = 0;
	btrfs_free_path(path);
	return ret;
}

/*
 * 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;

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

	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);

	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.offset = ref_offset;
	key.type = BTRFS_EXTENT_DATA_KEY;

	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;
	u32 blocksize;
	int ret;
	int err = 0;

	ret = get_new_location(rc->data_inode, NULL, extent_key->objectid,
			       extent_key->offset);
	BUG_ON(ret < 0);
	if (ret > 0) {
		/* the relocated data is fragmented */
		rc->extents_skipped++;
		btrfs_release_path(rc->extent_root, path);
		return 0;
	}

	blocksize = btrfs_level_size(rc->extent_root, 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]++;
	}
	btrfs_release_path(rc->extent_root, path);
	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,
		     struct reloc_control *rc, struct btrfs_path *path)
{
	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) {
			btrfs_release_path(rc->extent_root, path);
			rc->search_start = end + 1;
		} else {
			rc->search_start = key.objectid + key.offset;
			return 0;
		}
	}
	btrfs_release_path(rc->extent_root, path);
	return ret;
}

static void set_reloc_control(struct reloc_control *rc)
{
	struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
	mutex_lock(&fs_info->trans_mutex);
	fs_info->reloc_ctl = rc;
	mutex_unlock(&fs_info->trans_mutex);
}

static void unset_reloc_control(struct reloc_control *rc)
{
	struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
	mutex_lock(&fs_info->trans_mutex);
	fs_info->reloc_ctl = NULL;
	mutex_unlock(&fs_info->trans_mutex);
}

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;
}

3264

3265 3266 3267 3268
static noinline_for_stack int relocate_block_group(struct reloc_control *rc)
{
	struct rb_root blocks = RB_ROOT;
	struct btrfs_key key;
3269
	struct file_extent_cluster *cluster;
3270 3271 3272 3273 3274 3275 3276 3277 3278
	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;

3279 3280 3281 3282
	cluster = kzalloc(sizeof(*cluster), GFP_NOFS);
	if (!cluster)
		return -ENOMEM;

3283 3284 3285 3286
	path = btrfs_alloc_path();
	if (!path)
		return -ENOMEM;

3287 3288 3289
	rc->extents_found = 0;
	rc->extents_skipped = 0;

3290 3291 3292 3293 3294 3295 3296 3297 3298 3299 3300 3301 3302 3303 3304 3305 3306 3307 3308 3309 3310 3311 3312 3313 3314 3315 3316 3317 3318 3319 3320 3321 3322 3323 3324 3325 3326 3327 3328 3329 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
	rc->search_start = rc->block_group->key.objectid;
	clear_extent_bits(&rc->processed_blocks, 0, (u64)-1, EXTENT_DIRTY,
			  GFP_NOFS);

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

	trans = btrfs_start_transaction(rc->extent_root, 1);
	btrfs_commit_transaction(trans, rc->extent_root);

	while (1) {
		trans = btrfs_start_transaction(rc->extent_root, 1);

		ret = find_next_extent(trans, rc, path);
		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);
		btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
		item_size = btrfs_item_size_nr(path->nodes[0],
					       path->slots[0]);
		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) {
				btrfs_release_path(rc->extent_root, path);

				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 &&
			 (flags & BTRFS_EXTENT_FLAG_DATA)) {
			ret = add_data_references(rc, &key, path, &blocks);
		} else {
			btrfs_release_path(rc->extent_root, path);
			ret = 0;
		}
		if (ret < 0) {
			err = 0;
			break;
		}

		if (!RB_EMPTY_ROOT(&blocks)) {
			ret = relocate_tree_blocks(trans, rc, &blocks);
			if (ret < 0) {
				err = ret;
				break;
			}
		}

		nr = trans->blocks_used;
3376
		btrfs_end_transaction(trans, rc->extent_root);
3377 3378 3379 3380 3381 3382
		trans = NULL;
		btrfs_btree_balance_dirty(rc->extent_root, nr);

		if (rc->stage == MOVE_DATA_EXTENTS &&
		    (flags & BTRFS_EXTENT_FLAG_DATA)) {
			rc->found_file_extent = 1;
3383 3384
			ret = relocate_data_extent(rc->data_inode,
						   &key, cluster);
3385 3386 3387 3388 3389 3390 3391 3392 3393 3394 3395 3396 3397 3398
			if (ret < 0) {
				err = ret;
				break;
			}
		}
	}
	btrfs_free_path(path);

	if (trans) {
		nr = trans->blocks_used;
		btrfs_end_transaction(trans, rc->extent_root);
		btrfs_btree_balance_dirty(rc->extent_root, nr);
	}

3399 3400 3401 3402 3403 3404 3405 3406
	if (!err) {
		ret = relocate_file_extent_cluster(rc->data_inode, cluster);
		if (ret < 0)
			err = ret;
	}

	kfree(cluster);

3407 3408 3409 3410 3411 3412 3413 3414 3415 3416 3417 3418 3419 3420 3421 3422 3423 3424 3425 3426
	rc->create_reloc_root = 0;
	smp_mb();

	if (rc->extents_found > 0) {
		trans = btrfs_start_transaction(rc->extent_root, 1);
		btrfs_commit_transaction(trans, rc->extent_root);
	}

	merge_reloc_roots(rc);

	unset_reloc_control(rc);

	/* get rid of pinned extents */
	trans = btrfs_start_transaction(rc->extent_root, 1);
	btrfs_commit_transaction(trans, rc->extent_root);

	return err;
}

static int __insert_orphan_inode(struct btrfs_trans_handle *trans,
3427
				 struct btrfs_root *root, u64 objectid)
3428 3429 3430 3431 3432 3433 3434 3435 3436 3437 3438 3439 3440 3441 3442 3443 3444 3445
{
	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);
3446
	btrfs_set_inode_size(leaf, item, 0);
3447 3448 3449 3450 3451 3452 3453 3454 3455 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
	btrfs_set_inode_mode(leaf, item, S_IFREG | 0600);
	btrfs_set_inode_flags(leaf, item, BTRFS_INODE_NOCOMPRESS);
	btrfs_mark_buffer_dirty(leaf);
	btrfs_release_path(root, path);
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
 */
static struct inode *create_reloc_inode(struct btrfs_fs_info *fs_info,
					struct btrfs_block_group_cache *group)
{
	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);

	trans = btrfs_start_transaction(root, 1);
	BUG_ON(!trans);

	err = btrfs_find_free_objectid(trans, root, objectid, &objectid);
	if (err)
		goto out;

3482
	err = __insert_orphan_inode(trans, root, objectid);
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
	BUG_ON(err);

	key.objectid = objectid;
	key.type = BTRFS_INODE_ITEM_KEY;
	key.offset = 0;
	inode = btrfs_iget(root->fs_info->sb, &key, root);
	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;
}

/*
 * 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;
	int ret;
	int err = 0;

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

	mapping_tree_init(&rc->reloc_root_tree);
	extent_io_tree_init(&rc->processed_blocks, NULL, GFP_NOFS);
	INIT_LIST_HEAD(&rc->reloc_roots);

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

	btrfs_init_workers(&rc->workers, "relocate",
3528
			   fs_info->thread_pool_size, NULL);
3529 3530 3531 3532 3533 3534 3535 3536 3537 3538 3539 3540 3541 3542 3543 3544 3545 3546 3547 3548 3549 3550

	rc->extent_root = extent_root;
	btrfs_prepare_block_group_relocation(extent_root, rc->block_group);

	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);

	btrfs_start_delalloc_inodes(fs_info->tree_root);
	btrfs_wait_ordered_extents(fs_info->tree_root, 0);

	while (1) {
		rc->extents_found = 0;
		rc->extents_skipped = 0;

3551 3552 3553
		mutex_lock(&fs_info->cleaner_mutex);

		btrfs_clean_old_snapshots(fs_info->tree_root);
3554
		ret = relocate_block_group(rc);
3555 3556

		mutex_unlock(&fs_info->cleaner_mutex);
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
		if (ret < 0) {
			err = ret;
			break;
		}

		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;
		} else if (rc->stage == UPDATE_DATA_PTRS &&
			   rc->extents_skipped >= rc->extents_found) {
			iput(rc->data_inode);
			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;
				break;
			}
			rc->stage = MOVE_DATA_EXTENTS;
			rc->found_file_extent = 0;
		}
	}

3588 3589 3590 3591
	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);
3592 3593 3594 3595 3596 3597 3598 3599 3600 3601 3602 3603

	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:
	iput(rc->data_inode);
	btrfs_stop_workers(&rc->workers);
	btrfs_put_block_group(rc->block_group);
	kfree(rc);
	return err;
}

3604 3605 3606 3607 3608 3609 3610 3611 3612 3613 3614 3615 3616 3617 3618 3619 3620 3621 3622 3623
static noinline_for_stack int mark_garbage_root(struct btrfs_root *root)
{
	struct btrfs_trans_handle *trans;
	int ret;

	trans = btrfs_start_transaction(root->fs_info->tree_root, 1);

	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;
}

3624 3625 3626 3627 3628 3629 3630 3631 3632 3633 3634 3635 3636 3637 3638 3639 3640 3641 3642 3643 3644 3645 3646 3647 3648 3649 3650 3651 3652 3653 3654 3655 3656 3657 3658 3659 3660 3661 3662 3663 3664 3665 3666 3667 3668 3669 3670 3671 3672 3673 3674 3675 3676 3677 3678 3679 3680 3681 3682
/*
 * 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;

	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]);
		btrfs_release_path(root->fs_info->tree_root, path);

		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)) {
3683 3684 3685 3686 3687 3688
				ret = PTR_ERR(fs_root);
				if (ret != -ENOENT) {
					err = ret;
					goto out;
				}
				mark_garbage_root(reloc_root);
3689 3690 3691 3692 3693 3694 3695 3696 3697 3698 3699 3700 3701 3702 3703 3704 3705 3706 3707 3708 3709 3710
			}
		}

		if (key.offset == 0)
			break;

		key.offset--;
	}
	btrfs_release_path(root->fs_info->tree_root, path);

	if (list_empty(&reloc_roots))
		goto out;

	rc = kzalloc(sizeof(*rc), GFP_NOFS);
	if (!rc) {
		err = -ENOMEM;
		goto out;
	}

	mapping_tree_init(&rc->reloc_root_tree);
	INIT_LIST_HEAD(&rc->reloc_roots);
	btrfs_init_workers(&rc->workers, "relocate",
3711
			   root->fs_info->thread_pool_size, NULL);
3712 3713 3714 3715 3716 3717 3718 3719 3720 3721 3722 3723 3724 3725 3726 3727 3728 3729 3730 3731 3732 3733 3734 3735 3736 3737 3738 3739 3740 3741 3742 3743 3744 3745 3746 3747 3748 3749 3750 3751 3752 3753 3754 3755 3756 3757 3758 3759 3760 3761 3762 3763 3764
	rc->extent_root = root->fs_info->extent_root;

	set_reloc_control(rc);

	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;
	}

	trans = btrfs_start_transaction(rc->extent_root, 1);
	btrfs_commit_transaction(trans, rc->extent_root);

	merge_reloc_roots(rc);

	unset_reloc_control(rc);

	trans = btrfs_start_transaction(rc->extent_root, 1);
	btrfs_commit_transaction(trans, rc->extent_root);
out:
	if (rc) {
		btrfs_stop_workers(&rc->workers);
		kfree(rc);
	}
	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);
3765
		btrfs_orphan_cleanup(fs_root);
3766 3767 3768 3769 3770 3771 3772 3773 3774 3775 3776 3777 3778 3779 3780 3781 3782 3783 3784 3785 3786 3787 3788 3789 3790 3791 3792 3793 3794 3795 3796 3797 3798 3799 3800 3801 3802 3803 3804 3805 3806 3807 3808 3809 3810 3811 3812
	}
	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,
				       disk_bytenr + len - 1, &list);

	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);
	return 0;
}