v4.19.13 snapshot.
diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c
new file mode 100644
index 0000000..0526b6c
--- /dev/null
+++ b/fs/btrfs/relocation.c
@@ -0,0 +1,4691 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2009 Oracle. All rights reserved.
+ */
+
+#include <linux/sched.h>
+#include <linux/pagemap.h>
+#include <linux/writeback.h>
+#include <linux/blkdev.h>
+#include <linux/rbtree.h>
+#include <linux/slab.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"
+#include "free-space-cache.h"
+#include "inode-map.h"
+#include "qgroup.h"
+#include "print-tree.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;
+
+ u64 new_bytenr;
+ /* objectid of tree block owner, can be not uptodate */
+ u64 owner;
+ /* link to pending, changed or detached list */
+ struct list_head list;
+ /* 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;
+ /* is the block in non-reference counted tree */
+ unsigned int cowonly:1;
+ /* 1 if no child node 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;
+ /*
+ * 1 if corresponding block has been cowed but some upper
+ * level block pointers may not point to the new location
+ */
+ unsigned int pending:1;
+ /*
+ * 1 if the backref node isn't connected to any other
+ * backref node.
+ */
+ unsigned int detached:1;
+};
+
+/*
+ * present a block pointer in the backref cache
+ */
+struct backref_edge {
+ struct list_head list[2];
+ struct backref_node *node[2];
+};
+
+#define LOWER 0
+#define UPPER 1
+#define RELOCATION_RESERVED_NODES 256
+
+struct backref_cache {
+ /* red black tree of all backref nodes in the cache */
+ struct rb_root rb_root;
+ /* for passing backref nodes to btrfs_reloc_cow_block */
+ struct backref_node *path[BTRFS_MAX_LEVEL];
+ /*
+ * list of blocks that have been cowed but some block
+ * pointers in upper level blocks may not reflect the
+ * new location
+ */
+ struct list_head pending[BTRFS_MAX_LEVEL];
+ /* list of backref nodes with no child node */
+ struct list_head leaves;
+ /* list of blocks that have been cowed in current transaction */
+ struct list_head changed;
+ /* list of detached backref node. */
+ struct list_head detached;
+
+ u64 last_trans;
+
+ int nr_nodes;
+ int nr_edges;
+};
+
+/*
+ * 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;
+};
+
+#define MAX_EXTENTS 128
+
+struct file_extent_cluster {
+ u64 start;
+ u64 end;
+ u64 boundary[MAX_EXTENTS];
+ unsigned int nr;
+};
+
+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_block_rsv *block_rsv;
+
+ struct backref_cache backref_cache;
+
+ struct file_extent_cluster cluster;
+ /* 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;
+ /* size of metadata reservation for merging reloc trees */
+ u64 merging_rsv_size;
+ /* size of relocated tree nodes */
+ u64 nodes_relocated;
+ /* reserved size for block group relocation*/
+ u64 reserved_bytes;
+
+ u64 search_start;
+ u64 extents_found;
+
+ unsigned int stage:8;
+ unsigned int create_reloc_tree:1;
+ unsigned int merge_reloc_tree:1;
+ unsigned int found_file_extent:1;
+};
+
+/* stages of data relocation */
+#define MOVE_DATA_EXTENTS 0
+#define UPDATE_DATA_PTRS 1
+
+static void remove_backref_node(struct backref_cache *cache,
+ struct backref_node *node);
+static void __mark_block_processed(struct reloc_control *rc,
+ struct backref_node *node);
+
+static void mapping_tree_init(struct mapping_tree *tree)
+{
+ tree->rb_root = RB_ROOT;
+ spin_lock_init(&tree->lock);
+}
+
+static void backref_cache_init(struct backref_cache *cache)
+{
+ int i;
+ cache->rb_root = RB_ROOT;
+ for (i = 0; i < BTRFS_MAX_LEVEL; i++)
+ INIT_LIST_HEAD(&cache->pending[i]);
+ INIT_LIST_HEAD(&cache->changed);
+ INIT_LIST_HEAD(&cache->detached);
+ INIT_LIST_HEAD(&cache->leaves);
+}
+
+static void backref_cache_cleanup(struct backref_cache *cache)
+{
+ struct backref_node *node;
+ int i;
+
+ while (!list_empty(&cache->detached)) {
+ node = list_entry(cache->detached.next,
+ struct backref_node, list);
+ remove_backref_node(cache, node);
+ }
+
+ while (!list_empty(&cache->leaves)) {
+ node = list_entry(cache->leaves.next,
+ struct backref_node, lower);
+ remove_backref_node(cache, node);
+ }
+
+ cache->last_trans = 0;
+
+ for (i = 0; i < BTRFS_MAX_LEVEL; i++)
+ ASSERT(list_empty(&cache->pending[i]));
+ ASSERT(list_empty(&cache->changed));
+ ASSERT(list_empty(&cache->detached));
+ ASSERT(RB_EMPTY_ROOT(&cache->rb_root));
+ ASSERT(!cache->nr_nodes);
+ ASSERT(!cache->nr_edges);
+}
+
+static struct backref_node *alloc_backref_node(struct backref_cache *cache)
+{
+ struct backref_node *node;
+
+ node = kzalloc(sizeof(*node), GFP_NOFS);
+ if (node) {
+ INIT_LIST_HEAD(&node->list);
+ INIT_LIST_HEAD(&node->upper);
+ INIT_LIST_HEAD(&node->lower);
+ RB_CLEAR_NODE(&node->rb_node);
+ cache->nr_nodes++;
+ }
+ return node;
+}
+
+static void free_backref_node(struct backref_cache *cache,
+ struct backref_node *node)
+{
+ if (node) {
+ cache->nr_nodes--;
+ kfree(node);
+ }
+}
+
+static struct backref_edge *alloc_backref_edge(struct backref_cache *cache)
+{
+ struct backref_edge *edge;
+
+ edge = kzalloc(sizeof(*edge), GFP_NOFS);
+ if (edge)
+ cache->nr_edges++;
+ return edge;
+}
+
+static void free_backref_edge(struct backref_cache *cache,
+ struct backref_edge *edge)
+{
+ if (edge) {
+ cache->nr_edges--;
+ kfree(edge);
+ }
+}
+
+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;
+}
+
+static void backref_tree_panic(struct rb_node *rb_node, int errno, u64 bytenr)
+{
+
+ struct btrfs_fs_info *fs_info = NULL;
+ struct backref_node *bnode = rb_entry(rb_node, struct backref_node,
+ rb_node);
+ if (bnode->root)
+ fs_info = bnode->root->fs_info;
+ btrfs_panic(fs_info, errno,
+ "Inconsistency in backref cache found at offset %llu",
+ bytenr);
+}
+
+/*
+ * 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];
+ }
+ BUG_ON(node->detached);
+ *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 unlock_node_buffer(struct backref_node *node)
+{
+ if (node->locked) {
+ btrfs_tree_unlock(node->eb);
+ node->locked = 0;
+ }
+}
+
+static void drop_node_buffer(struct backref_node *node)
+{
+ if (node->eb) {
+ unlock_node_buffer(node);
+ free_extent_buffer(node->eb);
+ node->eb = NULL;
+ }
+}
+
+static void drop_backref_node(struct backref_cache *tree,
+ struct backref_node *node)
+{
+ BUG_ON(!list_empty(&node->upper));
+
+ drop_node_buffer(node);
+ list_del(&node->list);
+ list_del(&node->lower);
+ if (!RB_EMPTY_NODE(&node->rb_node))
+ rb_erase(&node->rb_node, &tree->rb_root);
+ free_backref_node(tree, 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 && !node->detached);
+ 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]);
+ free_backref_edge(cache, edge);
+
+ if (RB_EMPTY_NODE(&upper->rb_node)) {
+ BUG_ON(!list_empty(&node->upper));
+ drop_backref_node(cache, node);
+ node = upper;
+ node->lowest = 1;
+ continue;
+ }
+ /*
+ * add the node to leaf node list if no other
+ * child block cached.
+ */
+ if (list_empty(&upper->lower)) {
+ list_add_tail(&upper->lower, &cache->leaves);
+ upper->lowest = 1;
+ }
+ }
+
+ drop_backref_node(cache, node);
+}
+
+static void update_backref_node(struct backref_cache *cache,
+ struct backref_node *node, u64 bytenr)
+{
+ struct rb_node *rb_node;
+ rb_erase(&node->rb_node, &cache->rb_root);
+ node->bytenr = bytenr;
+ rb_node = tree_insert(&cache->rb_root, node->bytenr, &node->rb_node);
+ if (rb_node)
+ backref_tree_panic(rb_node, -EEXIST, bytenr);
+}
+
+/*
+ * update backref cache after a transaction commit
+ */
+static int update_backref_cache(struct btrfs_trans_handle *trans,
+ struct backref_cache *cache)
+{
+ struct backref_node *node;
+ int level = 0;
+
+ if (cache->last_trans == 0) {
+ cache->last_trans = trans->transid;
+ return 0;
+ }
+
+ if (cache->last_trans == trans->transid)
+ return 0;
+
+ /*
+ * detached nodes are used to avoid unnecessary backref
+ * lookup. transaction commit changes the extent tree.
+ * so the detached nodes are no longer useful.
+ */
+ while (!list_empty(&cache->detached)) {
+ node = list_entry(cache->detached.next,
+ struct backref_node, list);
+ remove_backref_node(cache, node);
+ }
+
+ while (!list_empty(&cache->changed)) {
+ node = list_entry(cache->changed.next,
+ struct backref_node, list);
+ list_del_init(&node->list);
+ BUG_ON(node->pending);
+ update_backref_node(cache, node, node->new_bytenr);
+ }
+
+ /*
+ * some nodes can be left in the pending list if there were
+ * errors during processing the pending nodes.
+ */
+ for (level = 0; level < BTRFS_MAX_LEVEL; level++) {
+ list_for_each_entry(node, &cache->pending[level], list) {
+ BUG_ON(!node->pending);
+ if (node->bytenr == node->new_bytenr)
+ continue;
+ update_backref_node(cache, node, node->new_bytenr);
+ }
+ }
+
+ cache->last_trans = 0;
+ return 1;
+}
+
+
+static int should_ignore_root(struct btrfs_root *root)
+{
+ struct btrfs_root *reloc_root;
+
+ if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state))
+ return 0;
+
+ reloc_root = root->reloc_root;
+ if (!reloc_root)
+ return 0;
+
+ if (btrfs_root_last_snapshot(&reloc_root->root_item) ==
+ root->fs_info->running_transaction->transid - 1)
+ return 0;
+ /*
+ * if there is reloc tree and it was created in previous
+ * transaction backref lookup can find the reloc tree,
+ * so backref node for the fs tree root is useless for
+ * relocation.
+ */
+ return 1;
+}
+/*
+ * 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 ||
+ root_objectid == BTRFS_UUID_TREE_OBJECTID ||
+ root_objectid == BTRFS_QUOTA_TREE_OBJECTID ||
+ root_objectid == BTRFS_FREE_SPACE_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_get_fs_root(fs_info, &key, false);
+}
+
+static noinline_for_stack
+int find_inline_backref(struct extent_buffer *leaf, int slot,
+ unsigned long *ptr, unsigned long *end)
+{
+ struct btrfs_key key;
+ struct btrfs_extent_item *ei;
+ struct btrfs_tree_block_info *bi;
+ u32 item_size;
+
+ btrfs_item_key_to_cpu(leaf, &key, slot);
+
+ item_size = btrfs_item_size_nr(leaf, slot);
+ if (item_size < sizeof(*ei)) {
+ btrfs_print_v0_err(leaf->fs_info);
+ btrfs_handle_fs_error(leaf->fs_info, -EINVAL, NULL);
+ return 1;
+ }
+ ei = btrfs_item_ptr(leaf, slot, struct btrfs_extent_item);
+ WARN_ON(!(btrfs_extent_flags(leaf, ei) &
+ BTRFS_EXTENT_FLAG_TREE_BLOCK));
+
+ if (key.type == BTRFS_EXTENT_ITEM_KEY &&
+ item_size <= sizeof(*ei) + sizeof(*bi)) {
+ WARN_ON(item_size < sizeof(*ei) + sizeof(*bi));
+ return 1;
+ }
+ if (key.type == BTRFS_METADATA_ITEM_KEY &&
+ item_size <= sizeof(*ei)) {
+ WARN_ON(item_size < sizeof(*ei));
+ return 1;
+ }
+
+ if (key.type == BTRFS_EXTENT_ITEM_KEY) {
+ bi = (struct btrfs_tree_block_info *)(ei + 1);
+ *ptr = (unsigned long)(bi + 1);
+ } else {
+ *ptr = (unsigned long)(ei + 1);
+ }
+ *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 reference the block, and then check
+ * backrefs 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 noinline_for_stack
+struct backref_node *build_backref_tree(struct reloc_control *rc,
+ struct btrfs_key *node_key,
+ int level, u64 bytenr)
+{
+ struct backref_cache *cache = &rc->backref_cache;
+ 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);
+ LIST_HEAD(useless);
+ int cowonly;
+ int ret;
+ int err = 0;
+ bool need_check = true;
+
+ path1 = btrfs_alloc_path();
+ path2 = btrfs_alloc_path();
+ if (!path1 || !path2) {
+ err = -ENOMEM;
+ goto out;
+ }
+ path1->reada = READA_FORWARD;
+ path2->reada = READA_FORWARD;
+
+ node = alloc_backref_node(cache);
+ if (!node) {
+ err = -ENOMEM;
+ goto out;
+ }
+
+ node->bytenr = bytenr;
+ node->level = level;
+ node->lowest = 1;
+ cur = node;
+again:
+ end = 0;
+ ptr = 0;
+ key.objectid = cur->bytenr;
+ key.type = BTRFS_METADATA_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;
+ }
+ ASSERT(ret);
+ ASSERT(path1->slots[0]);
+
+ path1->slots[0]--;
+
+ WARN_ON(cur->checked);
+ if (!list_empty(&cur->upper)) {
+ /*
+ * the backref was added previously when processing
+ * backref of type BTRFS_TREE_BLOCK_REF_KEY
+ */
+ ASSERT(list_is_singular(&cur->upper));
+ edge = list_entry(cur->upper.next, struct backref_edge,
+ list[LOWER]);
+ ASSERT(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 ||
+ key.type == BTRFS_METADATA_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;
+ int type;
+ iref = (struct btrfs_extent_inline_ref *)ptr;
+ type = btrfs_get_extent_inline_ref_type(eb, iref,
+ BTRFS_REF_TYPE_BLOCK);
+ if (type == BTRFS_REF_TYPE_INVALID) {
+ err = -EUCLEAN;
+ goto out;
+ }
+ key.type = type;
+ 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;
+ }
+
+ if (key.type == BTRFS_SHARED_BLOCK_REF_KEY) {
+ if (key.objectid == key.offset) {
+ /*
+ * only root blocks of reloc trees use
+ * backref of this type.
+ */
+ root = find_reloc_root(rc, cur->bytenr);
+ ASSERT(root);
+ cur->root = root;
+ break;
+ }
+
+ edge = alloc_backref_edge(cache);
+ if (!edge) {
+ err = -ENOMEM;
+ goto out;
+ }
+ rb_node = tree_search(&cache->rb_root, key.offset);
+ if (!rb_node) {
+ upper = alloc_backref_node(cache);
+ if (!upper) {
+ free_backref_edge(cache, edge);
+ err = -ENOMEM;
+ goto out;
+ }
+ upper->bytenr = key.offset;
+ upper->level = cur->level + 1;
+ /*
+ * backrefs for the upper level block isn't
+ * cached, add the block to pending list
+ */
+ list_add_tail(&edge->list[UPPER], &list);
+ } else {
+ upper = rb_entry(rb_node, struct backref_node,
+ rb_node);
+ ASSERT(upper->checked);
+ INIT_LIST_HEAD(&edge->list[UPPER]);
+ }
+ list_add_tail(&edge->list[LOWER], &cur->upper);
+ edge->node[LOWER] = cur;
+ edge->node[UPPER] = upper;
+
+ goto next;
+ } else if (unlikely(key.type == BTRFS_EXTENT_REF_V0_KEY)) {
+ err = -EINVAL;
+ btrfs_print_v0_err(rc->extent_root->fs_info);
+ btrfs_handle_fs_error(rc->extent_root->fs_info, err,
+ NULL);
+ goto out;
+ } 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 (!test_bit(BTRFS_ROOT_REF_COWS, &root->state))
+ cur->cowonly = 1;
+
+ if (btrfs_root_level(&root->root_item) == cur->level) {
+ /* tree root */
+ ASSERT(btrfs_root_bytenr(&root->root_item) ==
+ cur->bytenr);
+ if (should_ignore_root(root))
+ list_add(&cur->list, &useless);
+ else
+ 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;
+ }
+ if (ret > 0 && path2->slots[level] > 0)
+ path2->slots[level]--;
+
+ eb = path2->nodes[level];
+ if (btrfs_node_blockptr(eb, path2->slots[level]) !=
+ cur->bytenr) {
+ btrfs_err(root->fs_info,
+ "couldn't find block (%llu) (level %d) in tree (%llu) with key (%llu %u %llu)",
+ cur->bytenr, level - 1, root->objectid,
+ node_key->objectid, node_key->type,
+ node_key->offset);
+ err = -ENOENT;
+ goto out;
+ }
+ lower = cur;
+ need_check = true;
+ for (; level < BTRFS_MAX_LEVEL; level++) {
+ if (!path2->nodes[level]) {
+ ASSERT(btrfs_root_bytenr(&root->root_item) ==
+ lower->bytenr);
+ if (should_ignore_root(root))
+ list_add(&lower->list, &useless);
+ else
+ lower->root = root;
+ break;
+ }
+
+ edge = alloc_backref_edge(cache);
+ if (!edge) {
+ err = -ENOMEM;
+ goto out;
+ }
+
+ eb = path2->nodes[level];
+ rb_node = tree_search(&cache->rb_root, eb->start);
+ if (!rb_node) {
+ upper = alloc_backref_node(cache);
+ if (!upper) {
+ free_backref_edge(cache, edge);
+ err = -ENOMEM;
+ goto out;
+ }
+ upper->bytenr = eb->start;
+ upper->owner = btrfs_header_owner(eb);
+ upper->level = lower->level + 1;
+ if (!test_bit(BTRFS_ROOT_REF_COWS,
+ &root->state))
+ upper->cowonly = 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, we only do this once
+ * while walking up a tree as we will catch
+ * anything else later on.
+ */
+ if (!upper->checked && need_check) {
+ need_check = false;
+ list_add_tail(&edge->list[UPPER],
+ &list);
+ } else {
+ if (upper->checked)
+ need_check = true;
+ INIT_LIST_HEAD(&edge->list[UPPER]);
+ }
+ } else {
+ upper = rb_entry(rb_node, struct backref_node,
+ rb_node);
+ ASSERT(upper->checked);
+ INIT_LIST_HEAD(&edge->list[UPPER]);
+ if (!upper->owner)
+ upper->owner = btrfs_header_owner(eb);
+ }
+ list_add_tail(&edge->list[LOWER], &lower->upper);
+ edge->node[LOWER] = lower;
+ edge->node[UPPER] = upper;
+
+ if (rb_node)
+ break;
+ lower = upper;
+ upper = NULL;
+ }
+ btrfs_release_path(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(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.
+ */
+ ASSERT(node->checked);
+ cowonly = node->cowonly;
+ if (!cowonly) {
+ rb_node = tree_insert(&cache->rb_root, node->bytenr,
+ &node->rb_node);
+ if (rb_node)
+ backref_tree_panic(rb_node, -EEXIST, node->bytenr);
+ list_add_tail(&node->lower, &cache->leaves);
+ }
+
+ 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 (upper->detached) {
+ list_del(&edge->list[LOWER]);
+ lower = edge->node[LOWER];
+ free_backref_edge(cache, edge);
+ if (list_empty(&lower->upper))
+ list_add(&lower->list, &useless);
+ continue;
+ }
+
+ 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;
+ }
+
+ if (!upper->checked) {
+ /*
+ * Still want to blow up for developers since this is a
+ * logic bug.
+ */
+ ASSERT(0);
+ err = -EINVAL;
+ goto out;
+ }
+ if (cowonly != upper->cowonly) {
+ ASSERT(0);
+ err = -EINVAL;
+ goto out;
+ }
+
+ if (!cowonly) {
+ rb_node = tree_insert(&cache->rb_root, upper->bytenr,
+ &upper->rb_node);
+ if (rb_node)
+ backref_tree_panic(rb_node, -EEXIST,
+ upper->bytenr);
+ }
+
+ list_add_tail(&edge->list[UPPER], &upper->lower);
+
+ list_for_each_entry(edge, &upper->upper, list[LOWER])
+ list_add_tail(&edge->list[UPPER], &list);
+ }
+ /*
+ * process useless backref nodes. backref nodes for tree leaves
+ * are deleted from the cache. backref nodes for upper level
+ * tree blocks are left in the cache to avoid unnecessary backref
+ * lookup.
+ */
+ while (!list_empty(&useless)) {
+ upper = list_entry(useless.next, struct backref_node, list);
+ list_del_init(&upper->list);
+ ASSERT(list_empty(&upper->upper));
+ if (upper == node)
+ node = NULL;
+ if (upper->lowest) {
+ list_del_init(&upper->lower);
+ upper->lowest = 0;
+ }
+ while (!list_empty(&upper->lower)) {
+ edge = list_entry(upper->lower.next,
+ struct backref_edge, list[UPPER]);
+ list_del(&edge->list[UPPER]);
+ list_del(&edge->list[LOWER]);
+ lower = edge->node[LOWER];
+ free_backref_edge(cache, edge);
+
+ if (list_empty(&lower->upper))
+ list_add(&lower->list, &useless);
+ }
+ __mark_block_processed(rc, upper);
+ if (upper->level > 0) {
+ list_add(&upper->list, &cache->detached);
+ upper->detached = 1;
+ } else {
+ rb_erase(&upper->rb_node, &cache->rb_root);
+ free_backref_node(cache, upper);
+ }
+ }
+out:
+ btrfs_free_path(path1);
+ btrfs_free_path(path2);
+ if (err) {
+ while (!list_empty(&useless)) {
+ lower = list_entry(useless.next,
+ struct backref_node, list);
+ list_del_init(&lower->list);
+ }
+ while (!list_empty(&list)) {
+ edge = list_first_entry(&list, struct backref_edge,
+ list[UPPER]);
+ list_del(&edge->list[UPPER]);
+ list_del(&edge->list[LOWER]);
+ lower = edge->node[LOWER];
+ upper = edge->node[UPPER];
+ free_backref_edge(cache, edge);
+
+ /*
+ * Lower is no longer linked to any upper backref nodes
+ * and isn't in the cache, we can free it ourselves.
+ */
+ if (list_empty(&lower->upper) &&
+ RB_EMPTY_NODE(&lower->rb_node))
+ list_add(&lower->list, &useless);
+
+ if (!RB_EMPTY_NODE(&upper->rb_node))
+ continue;
+
+ /* Add this guy's upper edges to the list to process */
+ list_for_each_entry(edge, &upper->upper, list[LOWER])
+ list_add_tail(&edge->list[UPPER], &list);
+ if (list_empty(&upper->upper))
+ list_add(&upper->list, &useless);
+ }
+
+ while (!list_empty(&useless)) {
+ lower = list_entry(useless.next,
+ struct backref_node, list);
+ list_del_init(&lower->list);
+ if (lower == node)
+ node = NULL;
+ free_backref_node(cache, lower);
+ }
+
+ free_backref_node(cache, node);
+ return ERR_PTR(err);
+ }
+ ASSERT(!node || !node->detached);
+ return node;
+}
+
+/*
+ * helper to add backref node for the newly created snapshot.
+ * the backref node is created by cloning backref node that
+ * corresponds to root of source tree
+ */
+static int clone_backref_node(struct btrfs_trans_handle *trans,
+ struct reloc_control *rc,
+ struct btrfs_root *src,
+ struct btrfs_root *dest)
+{
+ struct btrfs_root *reloc_root = src->reloc_root;
+ struct backref_cache *cache = &rc->backref_cache;
+ struct backref_node *node = NULL;
+ struct backref_node *new_node;
+ struct backref_edge *edge;
+ struct backref_edge *new_edge;
+ struct rb_node *rb_node;
+
+ if (cache->last_trans > 0)
+ update_backref_cache(trans, cache);
+
+ rb_node = tree_search(&cache->rb_root, src->commit_root->start);
+ if (rb_node) {
+ node = rb_entry(rb_node, struct backref_node, rb_node);
+ if (node->detached)
+ node = NULL;
+ else
+ BUG_ON(node->new_bytenr != reloc_root->node->start);
+ }
+
+ if (!node) {
+ rb_node = tree_search(&cache->rb_root,
+ reloc_root->commit_root->start);
+ if (rb_node) {
+ node = rb_entry(rb_node, struct backref_node,
+ rb_node);
+ BUG_ON(node->detached);
+ }
+ }
+
+ if (!node)
+ return 0;
+
+ new_node = alloc_backref_node(cache);
+ if (!new_node)
+ return -ENOMEM;
+
+ new_node->bytenr = dest->node->start;
+ new_node->level = node->level;
+ new_node->lowest = node->lowest;
+ new_node->checked = 1;
+ new_node->root = dest;
+
+ if (!node->lowest) {
+ list_for_each_entry(edge, &node->lower, list[UPPER]) {
+ new_edge = alloc_backref_edge(cache);
+ if (!new_edge)
+ goto fail;
+
+ new_edge->node[UPPER] = new_node;
+ new_edge->node[LOWER] = edge->node[LOWER];
+ list_add_tail(&new_edge->list[UPPER],
+ &new_node->lower);
+ }
+ } else {
+ list_add_tail(&new_node->lower, &cache->leaves);
+ }
+
+ rb_node = tree_insert(&cache->rb_root, new_node->bytenr,
+ &new_node->rb_node);
+ if (rb_node)
+ backref_tree_panic(rb_node, -EEXIST, new_node->bytenr);
+
+ if (!new_node->lowest) {
+ list_for_each_entry(new_edge, &new_node->lower, list[UPPER]) {
+ list_add_tail(&new_edge->list[LOWER],
+ &new_edge->node[LOWER]->upper);
+ }
+ }
+ return 0;
+fail:
+ while (!list_empty(&new_node->lower)) {
+ new_edge = list_entry(new_node->lower.next,
+ struct backref_edge, list[UPPER]);
+ list_del(&new_edge->list[UPPER]);
+ free_backref_edge(cache, new_edge);
+ }
+ free_backref_node(cache, new_node);
+ return -ENOMEM;
+}
+
+/*
+ * helper to add 'address of tree root -> reloc tree' mapping
+ */
+static int __must_check __add_reloc_root(struct btrfs_root *root)
+{
+ struct btrfs_fs_info *fs_info = root->fs_info;
+ struct rb_node *rb_node;
+ struct mapping_node *node;
+ struct reloc_control *rc = fs_info->reloc_ctl;
+
+ node = kmalloc(sizeof(*node), GFP_NOFS);
+ if (!node)
+ return -ENOMEM;
+
+ 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);
+ if (rb_node) {
+ btrfs_panic(fs_info, -EEXIST,
+ "Duplicate root found for start=%llu while inserting into relocation tree",
+ node->bytenr);
+ }
+
+ list_add_tail(&root->root_list, &rc->reloc_roots);
+ return 0;
+}
+
+/*
+ * helper to delete the 'address of tree root -> reloc tree'
+ * mapping
+ */
+static void __del_reloc_root(struct btrfs_root *root)
+{
+ struct btrfs_fs_info *fs_info = root->fs_info;
+ struct rb_node *rb_node;
+ struct mapping_node *node = NULL;
+ struct reloc_control *rc = fs_info->reloc_ctl;
+
+ if (rc && root->node) {
+ spin_lock(&rc->reloc_root_tree.lock);
+ rb_node = tree_search(&rc->reloc_root_tree.rb_root,
+ root->node->start);
+ if (rb_node) {
+ node = rb_entry(rb_node, struct mapping_node, rb_node);
+ rb_erase(&node->rb_node, &rc->reloc_root_tree.rb_root);
+ }
+ spin_unlock(&rc->reloc_root_tree.lock);
+ if (!node)
+ return;
+ BUG_ON((struct btrfs_root *)node->data != root);
+ }
+
+ spin_lock(&fs_info->trans_lock);
+ list_del_init(&root->root_list);
+ spin_unlock(&fs_info->trans_lock);
+ kfree(node);
+}
+
+/*
+ * helper to update the 'address of tree root -> reloc tree'
+ * mapping
+ */
+static int __update_reloc_root(struct btrfs_root *root, u64 new_bytenr)
+{
+ struct btrfs_fs_info *fs_info = root->fs_info;
+ struct rb_node *rb_node;
+ struct mapping_node *node = NULL;
+ struct reloc_control *rc = fs_info->reloc_ctl;
+
+ spin_lock(&rc->reloc_root_tree.lock);
+ rb_node = tree_search(&rc->reloc_root_tree.rb_root,
+ root->node->start);
+ if (rb_node) {
+ node = rb_entry(rb_node, struct mapping_node, rb_node);
+ rb_erase(&node->rb_node, &rc->reloc_root_tree.rb_root);
+ }
+ spin_unlock(&rc->reloc_root_tree.lock);
+
+ if (!node)
+ return 0;
+ BUG_ON((struct btrfs_root *)node->data != root);
+
+ spin_lock(&rc->reloc_root_tree.lock);
+ node->bytenr = new_bytenr;
+ rb_node = tree_insert(&rc->reloc_root_tree.rb_root,
+ node->bytenr, &node->rb_node);
+ spin_unlock(&rc->reloc_root_tree.lock);
+ if (rb_node)
+ backref_tree_panic(rb_node, -EEXIST, node->bytenr);
+ return 0;
+}
+
+static struct btrfs_root *create_reloc_root(struct btrfs_trans_handle *trans,
+ struct btrfs_root *root, u64 objectid)
+{
+ struct btrfs_fs_info *fs_info = root->fs_info;
+ struct btrfs_root *reloc_root;
+ struct extent_buffer *eb;
+ struct btrfs_root_item *root_item;
+ struct btrfs_key root_key;
+ int ret;
+
+ root_item = kmalloc(sizeof(*root_item), GFP_NOFS);
+ BUG_ON(!root_item);
+
+ root_key.objectid = BTRFS_TREE_RELOC_OBJECTID;
+ root_key.type = BTRFS_ROOT_ITEM_KEY;
+ root_key.offset = objectid;
+
+ if (root->root_key.objectid == objectid) {
+ u64 commit_root_gen;
+
+ /* called by btrfs_init_reloc_root */
+ ret = btrfs_copy_root(trans, root, root->commit_root, &eb,
+ BTRFS_TREE_RELOC_OBJECTID);
+ BUG_ON(ret);
+ /*
+ * Set the last_snapshot field to the generation of the commit
+ * root - like this ctree.c:btrfs_block_can_be_shared() behaves
+ * correctly (returns true) when the relocation root is created
+ * either inside the critical section of a transaction commit
+ * (through transaction.c:qgroup_account_snapshot()) and when
+ * it's created before the transaction commit is started.
+ */
+ commit_root_gen = btrfs_header_generation(root->commit_root);
+ btrfs_set_root_last_snapshot(&root->root_item, commit_root_gen);
+ } else {
+ /*
+ * called by btrfs_reloc_post_snapshot_hook.
+ * the source tree is a reloc tree, all tree blocks
+ * modified after it was created have RELOC flag
+ * set in their headers. so it's OK to not update
+ * the 'last_snapshot'.
+ */
+ ret = btrfs_copy_root(trans, root, root->node, &eb,
+ BTRFS_TREE_RELOC_OBJECTID);
+ BUG_ON(ret);
+ }
+
+ memcpy(root_item, &root->root_item, sizeof(*root_item));
+ btrfs_set_root_bytenr(root_item, eb->start);
+ btrfs_set_root_level(root_item, btrfs_header_level(eb));
+ btrfs_set_root_generation(root_item, trans->transid);
+
+ if (root->root_key.objectid == objectid) {
+ btrfs_set_root_refs(root_item, 0);
+ memset(&root_item->drop_progress, 0,
+ sizeof(struct btrfs_disk_key));
+ root_item->drop_level = 0;
+ }
+
+ btrfs_tree_unlock(eb);
+ free_extent_buffer(eb);
+
+ ret = btrfs_insert_root(trans, fs_info->tree_root,
+ &root_key, root_item);
+ BUG_ON(ret);
+ kfree(root_item);
+
+ reloc_root = btrfs_read_fs_root(fs_info->tree_root, &root_key);
+ BUG_ON(IS_ERR(reloc_root));
+ reloc_root->last_trans = trans->transid;
+ return reloc_root;
+}
+
+/*
+ * create reloc tree for a given fs tree. reloc tree is just a
+ * snapshot of the fs tree with special root objectid.
+ */
+int btrfs_init_reloc_root(struct btrfs_trans_handle *trans,
+ struct btrfs_root *root)
+{
+ struct btrfs_fs_info *fs_info = root->fs_info;
+ struct btrfs_root *reloc_root;
+ struct reloc_control *rc = fs_info->reloc_ctl;
+ struct btrfs_block_rsv *rsv;
+ int clear_rsv = 0;
+ int ret;
+
+ if (root->reloc_root) {
+ reloc_root = root->reloc_root;
+ reloc_root->last_trans = trans->transid;
+ return 0;
+ }
+
+ if (!rc || !rc->create_reloc_tree ||
+ root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID)
+ return 0;
+
+ if (!trans->reloc_reserved) {
+ rsv = trans->block_rsv;
+ trans->block_rsv = rc->block_rsv;
+ clear_rsv = 1;
+ }
+ reloc_root = create_reloc_root(trans, root, root->root_key.objectid);
+ if (clear_rsv)
+ trans->block_rsv = rsv;
+
+ ret = __add_reloc_root(reloc_root);
+ BUG_ON(ret < 0);
+ 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_fs_info *fs_info = root->fs_info;
+ struct btrfs_root *reloc_root;
+ struct btrfs_root_item *root_item;
+ int ret;
+
+ if (!root->reloc_root)
+ goto out;
+
+ reloc_root = root->reloc_root;
+ root_item = &reloc_root->root_item;
+
+ if (fs_info->reloc_ctl->merge_reloc_tree &&
+ btrfs_root_refs(root_item) == 0) {
+ root->reloc_root = NULL;
+ __del_reloc_root(reloc_root);
+ }
+
+ 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, fs_info->tree_root,
+ &reloc_root->root_key, root_item);
+ BUG_ON(ret);
+
+out:
+ 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 < btrfs_ino(entry))
+ node = node->rb_left;
+ else if (objectid > btrfs_ino(entry))
+ node = node->rb_right;
+ else
+ break;
+ }
+ if (!node) {
+ while (prev) {
+ entry = rb_entry(prev, struct btrfs_inode, rb_node);
+ if (objectid <= btrfs_ino(entry)) {
+ 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 = btrfs_ino(entry) + 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,
+ btrfs_ino(BTRFS_I(reloc_inode)), 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 = -EINVAL;
+ goto out;
+ }
+
+ *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 noinline_for_stack
+int replace_file_extents(struct btrfs_trans_handle *trans,
+ struct reloc_control *rc,
+ struct btrfs_root *root,
+ struct extent_buffer *leaf)
+{
+ struct btrfs_fs_info *fs_info = root->fs_info;
+ struct btrfs_key key;
+ struct btrfs_file_extent_item *fi;
+ struct inode *inode = NULL;
+ u64 parent;
+ u64 bytenr;
+ u64 new_bytenr = 0;
+ u64 num_bytes;
+ u64 end;
+ u32 nritems;
+ u32 i;
+ int ret = 0;
+ int first = 1;
+ int dirty = 0;
+
+ if (rc->stage != UPDATE_DATA_PTRS)
+ return 0;
+
+ /* reloc trees always use full backref */
+ if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID)
+ parent = leaf->start;
+ else
+ parent = 0;
+
+ nritems = btrfs_header_nritems(leaf);
+ for (i = 0; i < nritems; i++) {
+ cond_resched();
+ btrfs_item_key_to_cpu(leaf, &key, i);
+ if (key.type != BTRFS_EXTENT_DATA_KEY)
+ continue;
+ fi = btrfs_item_ptr(leaf, i, struct btrfs_file_extent_item);
+ if (btrfs_file_extent_type(leaf, fi) ==
+ BTRFS_FILE_EXTENT_INLINE)
+ continue;
+ bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
+ num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
+ if (bytenr == 0)
+ continue;
+ if (!in_block_group(bytenr, rc->block_group))
+ continue;
+
+ /*
+ * if we are modifying block in fs tree, wait for readpage
+ * to complete and drop the extent cache
+ */
+ if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
+ if (first) {
+ inode = find_next_inode(root, key.objectid);
+ first = 0;
+ } else if (inode && btrfs_ino(BTRFS_I(inode)) < key.objectid) {
+ btrfs_add_delayed_iput(inode);
+ inode = find_next_inode(root, key.objectid);
+ }
+ if (inode && btrfs_ino(BTRFS_I(inode)) == key.objectid) {
+ end = key.offset +
+ btrfs_file_extent_num_bytes(leaf, fi);
+ WARN_ON(!IS_ALIGNED(key.offset,
+ fs_info->sectorsize));
+ WARN_ON(!IS_ALIGNED(end, fs_info->sectorsize));
+ end--;
+ ret = try_lock_extent(&BTRFS_I(inode)->io_tree,
+ key.offset, end);
+ if (!ret)
+ continue;
+
+ btrfs_drop_extent_cache(BTRFS_I(inode),
+ key.offset, end, 1);
+ unlock_extent(&BTRFS_I(inode)->io_tree,
+ key.offset, end);
+ }
+ }
+
+ ret = get_new_location(rc->data_inode, &new_bytenr,
+ bytenr, num_bytes);
+ if (ret) {
+ /*
+ * Don't have to abort since we've not changed anything
+ * in the file extent yet.
+ */
+ break;
+ }
+
+ 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);
+ if (ret) {
+ btrfs_abort_transaction(trans, ret);
+ break;
+ }
+
+ ret = btrfs_free_extent(trans, root, bytenr, num_bytes,
+ parent, btrfs_header_owner(leaf),
+ key.objectid, key.offset);
+ if (ret) {
+ btrfs_abort_transaction(trans, ret);
+ break;
+ }
+ }
+ if (dirty)
+ btrfs_mark_buffer_dirty(leaf);
+ if (inode)
+ btrfs_add_delayed_iput(inode);
+ return ret;
+}
+
+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 noinline_for_stack
+int replace_path(struct btrfs_trans_handle *trans,
+ struct btrfs_root *dest, struct btrfs_root *src,
+ struct btrfs_path *path, struct btrfs_key *next_key,
+ int lowest_level, int max_level)
+{
+ struct btrfs_fs_info *fs_info = dest->fs_info;
+ 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 cow = 0;
+ int level;
+ int ret;
+ int slot;
+
+ BUG_ON(src->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
+ BUG_ON(dest->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID);
+
+ last_snapshot = btrfs_root_last_snapshot(&src->root_item);
+again:
+ 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;
+ }
+
+ if (cow) {
+ 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) {
+ struct btrfs_key first_key;
+
+ 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 = fs_info->nodesize;
+ old_ptr_gen = btrfs_node_ptr_generation(parent, slot);
+ btrfs_node_key_to_cpu(parent, &first_key, 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 (WARN_ON(new_bytenr > 0 && new_bytenr == old_bytenr)) {
+ ret = level;
+ break;
+ }
+
+ if (new_bytenr == 0 || old_ptr_gen > last_snapshot ||
+ memcmp_node_keys(parent, slot, path, level)) {
+ if (level <= lowest_level) {
+ ret = 0;
+ break;
+ }
+
+ eb = read_tree_block(fs_info, old_bytenr, old_ptr_gen,
+ level - 1, &first_key);
+ if (IS_ERR(eb)) {
+ ret = PTR_ERR(eb);
+ break;
+ } else if (!extent_buffer_uptodate(eb)) {
+ ret = -EIO;
+ free_extent_buffer(eb);
+ break;
+ }
+ btrfs_tree_lock(eb);
+ if (cow) {
+ ret = btrfs_cow_block(trans, dest, eb, parent,
+ slot, &eb);
+ BUG_ON(ret);
+ }
+ btrfs_set_lock_blocking(eb);
+
+ btrfs_tree_unlock(parent);
+ free_extent_buffer(parent);
+
+ parent = eb;
+ continue;
+ }
+
+ if (!cow) {
+ btrfs_tree_unlock(parent);
+ free_extent_buffer(parent);
+ cow = 1;
+ goto again;
+ }
+
+ btrfs_node_key_to_cpu(path->nodes[level], &key,
+ path->slots[level]);
+ btrfs_release_path(path);
+
+ path->lowest_level = level;
+ ret = btrfs_search_slot(trans, src, &key, path, 0, 1);
+ path->lowest_level = 0;
+ BUG_ON(ret);
+
+ /*
+ * Info qgroup to trace both subtrees.
+ *
+ * We must trace both trees.
+ * 1) Tree reloc subtree
+ * If not traced, we will leak data numbers
+ * 2) Fs subtree
+ * If not traced, we will double count old data
+ * and tree block numbers, if current trans doesn't free
+ * data reloc tree inode.
+ */
+ ret = btrfs_qgroup_trace_subtree(trans, parent,
+ btrfs_header_generation(parent),
+ btrfs_header_level(parent));
+ if (ret < 0)
+ break;
+ ret = btrfs_qgroup_trace_subtree(trans, path->nodes[level],
+ btrfs_header_generation(path->nodes[level]),
+ btrfs_header_level(path->nodes[level]));
+ if (ret < 0)
+ break;
+
+ /*
+ * 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 btrfs_fs_info *fs_info = root->fs_info;
+ struct extent_buffer *eb = NULL;
+ int i;
+ u64 bytenr;
+ u64 ptr_gen = 0;
+ u64 last_snapshot;
+ u32 nritems;
+
+ last_snapshot = btrfs_root_last_snapshot(&root->root_item);
+
+ for (i = *level; i > 0; i--) {
+ struct btrfs_key first_key;
+
+ 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]);
+ btrfs_node_key_to_cpu(eb, &first_key, path->slots[i]);
+ eb = read_tree_block(fs_info, bytenr, ptr_gen, i - 1,
+ &first_key);
+ if (IS_ERR(eb)) {
+ return PTR_ERR(eb);
+ } else if (!extent_buffer_uptodate(eb)) {
+ free_extent_buffer(eb);
+ return -EIO;
+ }
+ 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 btrfs_fs_info *fs_info = root->fs_info;
+ struct inode *inode = NULL;
+ u64 objectid;
+ u64 start, end;
+ u64 ino;
+
+ 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;
+ ino = btrfs_ino(BTRFS_I(inode));
+
+ if (ino > max_key->objectid) {
+ iput(inode);
+ break;
+ }
+
+ objectid = ino + 1;
+ if (!S_ISREG(inode->i_mode))
+ continue;
+
+ if (unlikely(min_key->objectid == 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, fs_info->sectorsize));
+ }
+ } else {
+ start = 0;
+ }
+
+ if (unlikely(max_key->objectid == 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, fs_info->sectorsize));
+ end--;
+ }
+ } else {
+ end = (u64)-1;
+ }
+
+ /* the lock_extent waits for readpage to complete */
+ lock_extent(&BTRFS_I(inode)->io_tree, start, end);
+ btrfs_drop_extent_cache(BTRFS_I(inode), start, end, 1);
+ unlock_extent(&BTRFS_I(inode)->io_tree, start, end);
+ }
+ return 0;
+}
+
+static int find_next_key(struct btrfs_path *path, int level,
+ struct btrfs_key *key)
+
+{
+ while (level < BTRFS_MAX_LEVEL) {
+ if (!path->nodes[level])
+ break;
+ if (path->slots[level] + 1 <
+ btrfs_header_nritems(path->nodes[level])) {
+ btrfs_node_key_to_cpu(path->nodes[level], key,
+ path->slots[level] + 1);
+ return 0;
+ }
+ level++;
+ }
+ return 1;
+}
+
+/*
+ * merge the relocated tree blocks in reloc tree with corresponding
+ * fs tree.
+ */
+static noinline_for_stack int merge_reloc_root(struct reloc_control *rc,
+ struct btrfs_root *root)
+{
+ struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
+ LIST_HEAD(inode_list);
+ struct btrfs_key key;
+ struct btrfs_key next_key;
+ struct btrfs_trans_handle *trans = NULL;
+ struct btrfs_root *reloc_root;
+ struct btrfs_root_item *root_item;
+ struct btrfs_path *path;
+ struct extent_buffer *leaf;
+ int level;
+ int max_level;
+ int replaced = 0;
+ int ret;
+ int err = 0;
+ u32 min_reserved;
+
+ path = btrfs_alloc_path();
+ if (!path)
+ return -ENOMEM;
+ path->reada = READA_FORWARD;
+
+ 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);
+ path->lowest_level = 0;
+ 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);
+ }
+
+ min_reserved = fs_info->nodesize * (BTRFS_MAX_LEVEL - 1) * 2;
+ memset(&next_key, 0, sizeof(next_key));
+
+ while (1) {
+ ret = btrfs_block_rsv_refill(root, rc->block_rsv, min_reserved,
+ BTRFS_RESERVE_FLUSH_ALL);
+ if (ret) {
+ err = ret;
+ goto out;
+ }
+ trans = btrfs_start_transaction(root, 0);
+ if (IS_ERR(trans)) {
+ err = PTR_ERR(trans);
+ trans = NULL;
+ goto out;
+ }
+ trans->block_rsv = rc->block_rsv;
+
+ replaced = 0;
+ max_level = level;
+
+ ret = walk_down_reloc_tree(reloc_root, path, &level);
+ if (ret < 0) {
+ err = ret;
+ goto out;
+ }
+ if (ret > 0)
+ break;
+
+ if (!find_next_key(path, level, &key) &&
+ btrfs_comp_cpu_keys(&next_key, &key) >= 0) {
+ ret = 0;
+ } else {
+ ret = replace_path(trans, root, reloc_root, path,
+ &next_key, 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;
+ }
+
+ 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;
+
+ btrfs_end_transaction_throttle(trans);
+ trans = NULL;
+
+ btrfs_btree_balance_dirty(fs_info);
+
+ 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);
+ btrfs_update_reloc_root(trans, root);
+ }
+
+ if (trans)
+ btrfs_end_transaction_throttle(trans);
+
+ btrfs_btree_balance_dirty(fs_info);
+
+ if (replaced && rc->stage == UPDATE_DATA_PTRS)
+ invalidate_extent_cache(root, &key, &next_key);
+
+ return err;
+}
+
+static noinline_for_stack
+int prepare_to_merge(struct reloc_control *rc, int err)
+{
+ struct btrfs_root *root = rc->extent_root;
+ struct btrfs_fs_info *fs_info = root->fs_info;
+ struct btrfs_root *reloc_root;
+ struct btrfs_trans_handle *trans;
+ LIST_HEAD(reloc_roots);
+ u64 num_bytes = 0;
+ int ret;
+
+ mutex_lock(&fs_info->reloc_mutex);
+ rc->merging_rsv_size += fs_info->nodesize * (BTRFS_MAX_LEVEL - 1) * 2;
+ rc->merging_rsv_size += rc->nodes_relocated * 2;
+ mutex_unlock(&fs_info->reloc_mutex);
+
+again:
+ if (!err) {
+ num_bytes = rc->merging_rsv_size;
+ ret = btrfs_block_rsv_add(root, rc->block_rsv, num_bytes,
+ BTRFS_RESERVE_FLUSH_ALL);
+ if (ret)
+ err = ret;
+ }
+
+ trans = btrfs_join_transaction(rc->extent_root);
+ if (IS_ERR(trans)) {
+ if (!err)
+ btrfs_block_rsv_release(fs_info, rc->block_rsv,
+ num_bytes);
+ return PTR_ERR(trans);
+ }
+
+ if (!err) {
+ if (num_bytes != rc->merging_rsv_size) {
+ btrfs_end_transaction(trans);
+ btrfs_block_rsv_release(fs_info, rc->block_rsv,
+ num_bytes);
+ goto again;
+ }
+ }
+
+ rc->merge_reloc_tree = 1;
+
+ while (!list_empty(&rc->reloc_roots)) {
+ reloc_root = list_entry(rc->reloc_roots.next,
+ struct btrfs_root, root_list);
+ list_del_init(&reloc_root->root_list);
+
+ root = read_fs_root(fs_info, reloc_root->root_key.offset);
+ BUG_ON(IS_ERR(root));
+ BUG_ON(root->reloc_root != reloc_root);
+
+ /*
+ * set reference count to 1, so btrfs_recover_relocation
+ * knows it should resumes merging
+ */
+ if (!err)
+ btrfs_set_root_refs(&reloc_root->root_item, 1);
+ btrfs_update_reloc_root(trans, root);
+
+ list_add(&reloc_root->root_list, &reloc_roots);
+ }
+
+ list_splice(&reloc_roots, &rc->reloc_roots);
+
+ if (!err)
+ btrfs_commit_transaction(trans);
+ else
+ btrfs_end_transaction(trans);
+ return err;
+}
+
+static noinline_for_stack
+void free_reloc_roots(struct list_head *list)
+{
+ struct btrfs_root *reloc_root;
+
+ while (!list_empty(list)) {
+ reloc_root = list_entry(list->next, struct btrfs_root,
+ root_list);
+ __del_reloc_root(reloc_root);
+ free_extent_buffer(reloc_root->node);
+ free_extent_buffer(reloc_root->commit_root);
+ reloc_root->node = NULL;
+ reloc_root->commit_root = NULL;
+ }
+}
+
+static noinline_for_stack
+void merge_reloc_roots(struct reloc_control *rc)
+{
+ struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
+ struct btrfs_root *root;
+ struct btrfs_root *reloc_root;
+ LIST_HEAD(reloc_roots);
+ int found = 0;
+ int ret = 0;
+again:
+ root = rc->extent_root;
+
+ /*
+ * this serializes us with btrfs_record_root_in_transaction,
+ * we have to make sure nobody is in the middle of
+ * adding their roots to the list while we are
+ * doing this splice
+ */
+ mutex_lock(&fs_info->reloc_mutex);
+ list_splice_init(&rc->reloc_roots, &reloc_roots);
+ mutex_unlock(&fs_info->reloc_mutex);
+
+ while (!list_empty(&reloc_roots)) {
+ found = 1;
+ reloc_root = list_entry(reloc_roots.next,
+ struct btrfs_root, root_list);
+
+ if (btrfs_root_refs(&reloc_root->root_item) > 0) {
+ root = read_fs_root(fs_info,
+ reloc_root->root_key.offset);
+ BUG_ON(IS_ERR(root));
+ BUG_ON(root->reloc_root != reloc_root);
+
+ ret = merge_reloc_root(rc, root);
+ if (ret) {
+ if (list_empty(&reloc_root->root_list))
+ list_add_tail(&reloc_root->root_list,
+ &reloc_roots);
+ goto out;
+ }
+ } else {
+ list_del_init(&reloc_root->root_list);
+ }
+
+ ret = btrfs_drop_snapshot(reloc_root, rc->block_rsv, 0, 1);
+ if (ret < 0) {
+ if (list_empty(&reloc_root->root_list))
+ list_add_tail(&reloc_root->root_list,
+ &reloc_roots);
+ goto out;
+ }
+ }
+
+ if (found) {
+ found = 0;
+ goto again;
+ }
+out:
+ if (ret) {
+ btrfs_handle_fs_error(fs_info, ret, NULL);
+ if (!list_empty(&reloc_roots))
+ free_reloc_roots(&reloc_roots);
+
+ /* new reloc root may be added */
+ mutex_lock(&fs_info->reloc_mutex);
+ list_splice_init(&rc->reloc_roots, &reloc_roots);
+ mutex_unlock(&fs_info->reloc_mutex);
+ if (!list_empty(&reloc_roots))
+ free_reloc_roots(&reloc_roots);
+ }
+
+ BUG_ON(!RB_EMPTY_ROOT(&rc->reloc_root_tree.rb_root));
+}
+
+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_fs_info *fs_info = reloc_root->fs_info;
+ struct btrfs_root *root;
+
+ if (reloc_root->last_trans == trans->transid)
+ return 0;
+
+ root = read_fs_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);
+}
+
+static noinline_for_stack
+struct btrfs_root *select_reloc_root(struct btrfs_trans_handle *trans,
+ struct reloc_control *rc,
+ struct backref_node *node,
+ struct backref_edge *edges[])
+{
+ struct backref_node *next;
+ struct btrfs_root *root;
+ int index = 0;
+
+ next = node;
+ while (1) {
+ cond_resched();
+ next = walk_up_backref(next, edges, &index);
+ root = next->root;
+ BUG_ON(!root);
+ BUG_ON(!test_bit(BTRFS_ROOT_REF_COWS, &root->state));
+
+ if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) {
+ record_reloc_root_in_trans(trans, root);
+ break;
+ }
+
+ btrfs_record_root_in_trans(trans, root);
+ root = root->reloc_root;
+
+ if (next->new_bytenr != root->node->start) {
+ BUG_ON(next->new_bytenr);
+ BUG_ON(!list_empty(&next->list));
+ next->new_bytenr = root->node->start;
+ next->root = root;
+ list_add_tail(&next->list,
+ &rc->backref_cache.changed);
+ __mark_block_processed(rc, next);
+ break;
+ }
+
+ WARN_ON(1);
+ root = NULL;
+ next = walk_down_backref(edges, &index);
+ if (!next || next->level <= node->level)
+ break;
+ }
+ if (!root)
+ return NULL;
+
+ next = node;
+ /* setup backref node path for btrfs_reloc_cow_block */
+ while (1) {
+ rc->backref_cache.path[next->level] = next;
+ if (--index < 0)
+ break;
+ next = edges[index]->node[UPPER];
+ }
+ return root;
+}
+
+/*
+ * select a tree root for relocation. return NULL if the block
+ * is reference counted. we should use do_relocation() in this
+ * case. return a tree root pointer if the block isn't reference
+ * counted. return -ENOENT if the block is root of reloc tree.
+ */
+static noinline_for_stack
+struct btrfs_root *select_one_root(struct backref_node *node)
+{
+ struct backref_node *next;
+ struct btrfs_root *root;
+ struct btrfs_root *fs_root = NULL;
+ struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
+ int index = 0;
+
+ next = node;
+ while (1) {
+ cond_resched();
+ next = walk_up_backref(next, edges, &index);
+ root = next->root;
+ BUG_ON(!root);
+
+ /* no other choice for non-references counted tree */
+ if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state))
+ return root;
+
+ if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID)
+ fs_root = root;
+
+ if (next != node)
+ return NULL;
+
+ next = walk_down_backref(edges, &index);
+ if (!next || next->level <= node->level)
+ break;
+ }
+
+ if (!fs_root)
+ return ERR_PTR(-ENOENT);
+ return fs_root;
+}
+
+static noinline_for_stack
+u64 calcu_metadata_size(struct reloc_control *rc,
+ struct backref_node *node, int reserve)
+{
+ struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
+ struct backref_node *next = node;
+ struct backref_edge *edge;
+ struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
+ u64 num_bytes = 0;
+ int index = 0;
+
+ BUG_ON(reserve && node->processed);
+
+ while (next) {
+ cond_resched();
+ while (1) {
+ if (next->processed && (reserve || next != node))
+ break;
+
+ num_bytes += fs_info->nodesize;
+
+ if (list_empty(&next->upper))
+ break;
+
+ edge = list_entry(next->upper.next,
+ struct backref_edge, list[LOWER]);
+ edges[index++] = edge;
+ next = edge->node[UPPER];
+ }
+ next = walk_down_backref(edges, &index);
+ }
+ return num_bytes;
+}
+
+static int reserve_metadata_space(struct btrfs_trans_handle *trans,
+ struct reloc_control *rc,
+ struct backref_node *node)
+{
+ struct btrfs_root *root = rc->extent_root;
+ struct btrfs_fs_info *fs_info = root->fs_info;
+ u64 num_bytes;
+ int ret;
+ u64 tmp;
+
+ num_bytes = calcu_metadata_size(rc, node, 1) * 2;
+
+ trans->block_rsv = rc->block_rsv;
+ rc->reserved_bytes += num_bytes;
+
+ /*
+ * We are under a transaction here so we can only do limited flushing.
+ * If we get an enospc just kick back -EAGAIN so we know to drop the
+ * transaction and try to refill when we can flush all the things.
+ */
+ ret = btrfs_block_rsv_refill(root, rc->block_rsv, num_bytes,
+ BTRFS_RESERVE_FLUSH_LIMIT);
+ if (ret) {
+ tmp = fs_info->nodesize * RELOCATION_RESERVED_NODES;
+ while (tmp <= rc->reserved_bytes)
+ tmp <<= 1;
+ /*
+ * only one thread can access block_rsv at this point,
+ * so we don't need hold lock to protect block_rsv.
+ * we expand more reservation size here to allow enough
+ * space for relocation and we will return eailer in
+ * enospc case.
+ */
+ rc->block_rsv->size = tmp + fs_info->nodesize *
+ RELOCATION_RESERVED_NODES;
+ return -EAGAIN;
+ }
+
+ return 0;
+}
+
+/*
+ * 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 reloc_control *rc,
+ struct backref_node *node,
+ struct btrfs_key *key,
+ struct btrfs_path *path, int lowest)
+{
+ struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
+ 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 slot;
+ int ret;
+ int err = 0;
+
+ BUG_ON(lowest && node->eb);
+
+ path->lowest_level = node->level + 1;
+ rc->backref_cache.path[node->level] = node;
+ list_for_each_entry(edge, &node->upper, list[LOWER]) {
+ struct btrfs_key first_key;
+
+ cond_resched();
+
+ upper = edge->node[UPPER];
+ root = select_reloc_root(trans, rc, upper, edges);
+ BUG_ON(!root);
+
+ if (upper->eb && !upper->locked) {
+ if (!lowest) {
+ ret = btrfs_bin_search(upper->eb, key,
+ upper->level, &slot);
+ BUG_ON(ret);
+ bytenr = btrfs_node_blockptr(upper->eb, slot);
+ if (node->eb->start == bytenr)
+ goto next;
+ }
+ drop_node_buffer(upper);
+ }
+
+ if (!upper->eb) {
+ ret = btrfs_search_slot(trans, root, key, path, 0, 1);
+ if (ret) {
+ if (ret < 0)
+ err = ret;
+ else
+ err = -ENOENT;
+
+ btrfs_release_path(path);
+ break;
+ }
+
+ if (!upper->eb) {
+ upper->eb = path->nodes[upper->level];
+ path->nodes[upper->level] = NULL;
+ } else {
+ BUG_ON(upper->eb != path->nodes[upper->level]);
+ }
+
+ upper->locked = 1;
+ path->locks[upper->level] = 0;
+
+ slot = path->slots[upper->level];
+ btrfs_release_path(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 (bytenr != node->bytenr) {
+ btrfs_err(root->fs_info,
+ "lowest leaf/node mismatch: bytenr %llu node->bytenr %llu slot %d upper %llu",
+ bytenr, node->bytenr, slot,
+ upper->eb->start);
+ err = -EIO;
+ goto next;
+ }
+ } else {
+ if (node->eb->start == bytenr)
+ goto next;
+ }
+
+ blocksize = root->fs_info->nodesize;
+ generation = btrfs_node_ptr_generation(upper->eb, slot);
+ btrfs_node_key_to_cpu(upper->eb, &first_key, slot);
+ eb = read_tree_block(fs_info, bytenr, generation,
+ upper->level - 1, &first_key);
+ if (IS_ERR(eb)) {
+ err = PTR_ERR(eb);
+ goto next;
+ } else if (!extent_buffer_uptodate(eb)) {
+ free_extent_buffer(eb);
+ err = -EIO;
+ goto next;
+ }
+ btrfs_tree_lock(eb);
+ btrfs_set_lock_blocking(eb);
+
+ if (!node->eb) {
+ ret = btrfs_cow_block(trans, root, eb, upper->eb,
+ slot, &eb);
+ btrfs_tree_unlock(eb);
+ free_extent_buffer(eb);
+ if (ret < 0) {
+ err = ret;
+ goto next;
+ }
+ BUG_ON(node->eb != eb);
+ } 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);
+ }
+next:
+ if (!upper->pending)
+ drop_node_buffer(upper);
+ else
+ unlock_node_buffer(upper);
+ if (err)
+ break;
+ }
+
+ if (!err && node->pending) {
+ drop_node_buffer(node);
+ list_move_tail(&node->list, &rc->backref_cache.changed);
+ node->pending = 0;
+ }
+
+ path->lowest_level = 0;
+ BUG_ON(err == -ENOSPC);
+ return err;
+}
+
+static int link_to_upper(struct btrfs_trans_handle *trans,
+ struct reloc_control *rc,
+ struct backref_node *node,
+ struct btrfs_path *path)
+{
+ struct btrfs_key key;
+
+ btrfs_node_key_to_cpu(node->eb, &key, 0);
+ return do_relocation(trans, rc, node, &key, path, 0);
+}
+
+static int finish_pending_nodes(struct btrfs_trans_handle *trans,
+ struct reloc_control *rc,
+ struct btrfs_path *path, int err)
+{
+ LIST_HEAD(list);
+ struct backref_cache *cache = &rc->backref_cache;
+ struct backref_node *node;
+ int level;
+ int ret;
+
+ for (level = 0; level < BTRFS_MAX_LEVEL; level++) {
+ while (!list_empty(&cache->pending[level])) {
+ node = list_entry(cache->pending[level].next,
+ struct backref_node, list);
+ list_move_tail(&node->list, &list);
+ BUG_ON(!node->pending);
+
+ if (!err) {
+ ret = link_to_upper(trans, rc, node, path);
+ if (ret < 0)
+ err = ret;
+ }
+ }
+ list_splice_init(&list, &cache->pending[level]);
+ }
+ return err;
+}
+
+static void mark_block_processed(struct reloc_control *rc,
+ u64 bytenr, u32 blocksize)
+{
+ set_extent_bits(&rc->processed_blocks, bytenr, bytenr + blocksize - 1,
+ EXTENT_DIRTY);
+}
+
+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 = rc->extent_root->fs_info->nodesize;
+ mark_block_processed(rc, node->bytenr, blocksize);
+ }
+ 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, struct reloc_control *rc)
+{
+ u32 blocksize = rc->extent_root->fs_info->nodesize;
+
+ if (test_range_bit(&rc->processed_blocks, bytenr,
+ bytenr + blocksize - 1, EXTENT_DIRTY, 1, NULL))
+ return 1;
+ return 0;
+}
+
+static int get_tree_block_key(struct btrfs_fs_info *fs_info,
+ struct tree_block *block)
+{
+ struct extent_buffer *eb;
+
+ BUG_ON(block->key_ready);
+ eb = read_tree_block(fs_info, block->bytenr, block->key.offset,
+ block->level, NULL);
+ if (IS_ERR(eb)) {
+ return PTR_ERR(eb);
+ } else if (!extent_buffer_uptodate(eb)) {
+ free_extent_buffer(eb);
+ return -EIO;
+ }
+ 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;
+}
+
+/*
+ * 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 = 0;
+
+ if (!node)
+ return 0;
+
+ BUG_ON(node->processed);
+ root = select_one_root(node);
+ if (root == ERR_PTR(-ENOENT)) {
+ update_processed_blocks(rc, node);
+ goto out;
+ }
+
+ if (!root || test_bit(BTRFS_ROOT_REF_COWS, &root->state)) {
+ ret = reserve_metadata_space(trans, rc, node);
+ if (ret)
+ goto out;
+ }
+
+ if (root) {
+ if (test_bit(BTRFS_ROOT_REF_COWS, &root->state)) {
+ BUG_ON(node->new_bytenr);
+ BUG_ON(!list_empty(&node->list));
+ btrfs_record_root_in_trans(trans, root);
+ root = root->reloc_root;
+ node->new_bytenr = root->node->start;
+ node->root = root;
+ list_add_tail(&node->list, &rc->backref_cache.changed);
+ } else {
+ path->lowest_level = node->level;
+ ret = btrfs_search_slot(trans, root, key, path, 0, 1);
+ btrfs_release_path(path);
+ if (ret > 0)
+ ret = 0;
+ }
+ if (!ret)
+ update_processed_blocks(rc, node);
+ } else {
+ ret = do_relocation(trans, rc, node, key, path, 1);
+ }
+out:
+ if (ret || node->level == 0 || node->cowonly)
+ remove_backref_node(&rc->backref_cache, 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 btrfs_fs_info *fs_info = rc->extent_root->fs_info;
+ struct backref_node *node;
+ struct btrfs_path *path;
+ struct tree_block *block;
+ struct rb_node *rb_node;
+ int ret;
+ int err = 0;
+
+ path = btrfs_alloc_path();
+ if (!path) {
+ err = -ENOMEM;
+ goto out_free_blocks;
+ }
+
+ rb_node = rb_first(blocks);
+ while (rb_node) {
+ block = rb_entry(rb_node, struct tree_block, rb_node);
+ if (!block->key_ready)
+ readahead_tree_block(fs_info, block->bytenr);
+ 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) {
+ err = get_tree_block_key(fs_info, block);
+ if (err)
+ goto out_free_path;
+ }
+ 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, &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) {
+ if (ret != -EAGAIN || rb_node == rb_first(blocks))
+ err = ret;
+ goto out;
+ }
+ rb_node = rb_next(rb_node);
+ }
+out:
+ err = finish_pending_nodes(trans, rc, path, err);
+
+out_free_path:
+ btrfs_free_path(path);
+out_free_blocks:
+ free_block_list(blocks);
+ return err;
+}
+
+static noinline_for_stack
+int prealloc_file_extent_cluster(struct inode *inode,
+ struct file_extent_cluster *cluster)
+{
+ u64 alloc_hint = 0;
+ u64 start;
+ u64 end;
+ u64 offset = BTRFS_I(inode)->index_cnt;
+ u64 num_bytes;
+ int nr = 0;
+ int ret = 0;
+ u64 prealloc_start = cluster->start - offset;
+ u64 prealloc_end = cluster->end - offset;
+ u64 cur_offset;
+ struct extent_changeset *data_reserved = NULL;
+
+ BUG_ON(cluster->start != cluster->boundary[0]);
+ inode_lock(inode);
+
+ ret = btrfs_check_data_free_space(inode, &data_reserved, prealloc_start,
+ prealloc_end + 1 - prealloc_start);
+ if (ret)
+ goto out;
+
+ cur_offset = prealloc_start;
+ while (nr < cluster->nr) {
+ start = cluster->boundary[nr] - offset;
+ if (nr + 1 < cluster->nr)
+ end = cluster->boundary[nr + 1] - 1 - offset;
+ else
+ end = cluster->end - offset;
+
+ lock_extent(&BTRFS_I(inode)->io_tree, start, end);
+ num_bytes = end + 1 - start;
+ if (cur_offset < start)
+ btrfs_free_reserved_data_space(inode, data_reserved,
+ cur_offset, start - cur_offset);
+ ret = btrfs_prealloc_file_range(inode, 0, start,
+ num_bytes, num_bytes,
+ end + 1, &alloc_hint);
+ cur_offset = end + 1;
+ unlock_extent(&BTRFS_I(inode)->io_tree, start, end);
+ if (ret)
+ break;
+ nr++;
+ }
+ if (cur_offset < prealloc_end)
+ btrfs_free_reserved_data_space(inode, data_reserved,
+ cur_offset, prealloc_end + 1 - cur_offset);
+out:
+ inode_unlock(inode);
+ extent_changeset_free(data_reserved);
+ return ret;
+}
+
+static noinline_for_stack
+int setup_extent_mapping(struct inode *inode, u64 start, u64 end,
+ u64 block_start)
+{
+ struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
+ struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
+ struct extent_map *em;
+ int ret = 0;
+
+ em = alloc_extent_map();
+ if (!em)
+ return -ENOMEM;
+
+ em->start = start;
+ em->len = end + 1 - start;
+ em->block_len = em->len;
+ em->block_start = block_start;
+ em->bdev = fs_info->fs_devices->latest_bdev;
+ set_bit(EXTENT_FLAG_PINNED, &em->flags);
+
+ lock_extent(&BTRFS_I(inode)->io_tree, start, end);
+ while (1) {
+ write_lock(&em_tree->lock);
+ ret = add_extent_mapping(em_tree, em, 0);
+ write_unlock(&em_tree->lock);
+ if (ret != -EEXIST) {
+ free_extent_map(em);
+ break;
+ }
+ btrfs_drop_extent_cache(BTRFS_I(inode), start, end, 0);
+ }
+ unlock_extent(&BTRFS_I(inode)->io_tree, start, end);
+ return ret;
+}
+
+static int relocate_file_extent_cluster(struct inode *inode,
+ struct file_extent_cluster *cluster)
+{
+ struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
+ u64 page_start;
+ u64 page_end;
+ u64 offset = BTRFS_I(inode)->index_cnt;
+ unsigned long index;
+ unsigned long last_index;
+ struct page *page;
+ struct file_ra_state *ra;
+ gfp_t mask = btrfs_alloc_write_mask(inode->i_mapping);
+ int nr = 0;
+ int ret = 0;
+
+ if (!cluster->nr)
+ return 0;
+
+ ra = kzalloc(sizeof(*ra), GFP_NOFS);
+ if (!ra)
+ return -ENOMEM;
+
+ ret = prealloc_file_extent_cluster(inode, cluster);
+ if (ret)
+ goto out;
+
+ file_ra_state_init(ra, inode->i_mapping);
+
+ ret = setup_extent_mapping(inode, cluster->start - offset,
+ cluster->end - offset, cluster->start);
+ if (ret)
+ goto out;
+
+ index = (cluster->start - offset) >> PAGE_SHIFT;
+ last_index = (cluster->end - offset) >> PAGE_SHIFT;
+ while (index <= last_index) {
+ ret = btrfs_delalloc_reserve_metadata(BTRFS_I(inode),
+ PAGE_SIZE);
+ if (ret)
+ goto out;
+
+ page = find_lock_page(inode->i_mapping, index);
+ if (!page) {
+ page_cache_sync_readahead(inode->i_mapping,
+ ra, NULL, index,
+ last_index + 1 - index);
+ page = find_or_create_page(inode->i_mapping, index,
+ mask);
+ if (!page) {
+ btrfs_delalloc_release_metadata(BTRFS_I(inode),
+ PAGE_SIZE, true);
+ ret = -ENOMEM;
+ goto out;
+ }
+ }
+
+ if (PageReadahead(page)) {
+ page_cache_async_readahead(inode->i_mapping,
+ ra, NULL, page, index,
+ last_index + 1 - index);
+ }
+
+ if (!PageUptodate(page)) {
+ btrfs_readpage(NULL, page);
+ lock_page(page);
+ if (!PageUptodate(page)) {
+ unlock_page(page);
+ put_page(page);
+ btrfs_delalloc_release_metadata(BTRFS_I(inode),
+ PAGE_SIZE, true);
+ btrfs_delalloc_release_extents(BTRFS_I(inode),
+ PAGE_SIZE, true);
+ ret = -EIO;
+ goto out;
+ }
+ }
+
+ page_start = page_offset(page);
+ page_end = page_start + PAGE_SIZE - 1;
+
+ lock_extent(&BTRFS_I(inode)->io_tree, page_start, page_end);
+
+ set_page_extent_mapped(page);
+
+ if (nr < cluster->nr &&
+ page_start + offset == cluster->boundary[nr]) {
+ set_extent_bits(&BTRFS_I(inode)->io_tree,
+ page_start, page_end,
+ EXTENT_BOUNDARY);
+ nr++;
+ }
+
+ ret = btrfs_set_extent_delalloc(inode, page_start, page_end, 0,
+ NULL, 0);
+ if (ret) {
+ unlock_page(page);
+ put_page(page);
+ btrfs_delalloc_release_metadata(BTRFS_I(inode),
+ PAGE_SIZE, true);
+ btrfs_delalloc_release_extents(BTRFS_I(inode),
+ PAGE_SIZE, true);
+
+ clear_extent_bits(&BTRFS_I(inode)->io_tree,
+ page_start, page_end,
+ EXTENT_LOCKED | EXTENT_BOUNDARY);
+ goto out;
+
+ }
+ set_page_dirty(page);
+
+ unlock_extent(&BTRFS_I(inode)->io_tree,
+ page_start, page_end);
+ unlock_page(page);
+ put_page(page);
+
+ index++;
+ btrfs_delalloc_release_extents(BTRFS_I(inode), PAGE_SIZE,
+ false);
+ balance_dirty_pages_ratelimited(inode->i_mapping);
+ btrfs_throttle(fs_info);
+ }
+ WARN_ON(nr != cluster->nr);
+out:
+ kfree(ra);
+ return ret;
+}
+
+static noinline_for_stack
+int relocate_data_extent(struct inode *inode, struct btrfs_key *extent_key,
+ struct file_extent_cluster *cluster)
+{
+ int ret;
+
+ if (cluster->nr > 0 && extent_key->objectid != cluster->end + 1) {
+ ret = relocate_file_extent_cluster(inode, cluster);
+ if (ret)
+ return ret;
+ cluster->nr = 0;
+ }
+
+ 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;
+}
+
+/*
+ * 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;
+ u64 generation;
+
+ eb = path->nodes[0];
+ item_size = btrfs_item_size_nr(eb, path->slots[0]);
+
+ if (extent_key->type == BTRFS_METADATA_ITEM_KEY ||
+ item_size >= sizeof(*ei) + sizeof(*bi)) {
+ ei = btrfs_item_ptr(eb, path->slots[0],
+ struct btrfs_extent_item);
+ if (extent_key->type == BTRFS_EXTENT_ITEM_KEY) {
+ bi = (struct btrfs_tree_block_info *)(ei + 1);
+ level = btrfs_tree_block_level(eb, bi);
+ } else {
+ level = (int)extent_key->offset;
+ }
+ generation = btrfs_extent_generation(eb, ei);
+ } else if (unlikely(item_size == sizeof(struct btrfs_extent_item_v0))) {
+ btrfs_print_v0_err(eb->fs_info);
+ btrfs_handle_fs_error(eb->fs_info, -EINVAL, NULL);
+ return -EINVAL;
+ } else {
+ BUG();
+ }
+
+ btrfs_release_path(path);
+
+ BUG_ON(level == -1);
+
+ block = kmalloc(sizeof(*block), GFP_NOFS);
+ if (!block)
+ return -ENOMEM;
+
+ block->bytenr = extent_key->objectid;
+ block->key.objectid = rc->extent_root->fs_info->nodesize;
+ block->key.offset = generation;
+ block->level = level;
+ block->key_ready = 0;
+
+ rb_node = tree_insert(blocks, block->bytenr, &block->rb_node);
+ if (rb_node)
+ backref_tree_panic(rb_node, -EEXIST, block->bytenr);
+
+ 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_fs_info *fs_info = rc->extent_root->fs_info;
+ struct btrfs_path *path;
+ struct btrfs_key key;
+ int ret;
+ bool skinny = btrfs_fs_incompat(fs_info, SKINNY_METADATA);
+
+ if (tree_block_processed(bytenr, rc))
+ return 0;
+
+ if (tree_search(blocks, bytenr))
+ return 0;
+
+ path = btrfs_alloc_path();
+ if (!path)
+ return -ENOMEM;
+again:
+ key.objectid = bytenr;
+ if (skinny) {
+ key.type = BTRFS_METADATA_ITEM_KEY;
+ key.offset = (u64)-1;
+ } else {
+ 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;
+
+ if (ret > 0 && skinny) {
+ if (path->slots[0]) {
+ path->slots[0]--;
+ btrfs_item_key_to_cpu(path->nodes[0], &key,
+ path->slots[0]);
+ if (key.objectid == bytenr &&
+ (key.type == BTRFS_METADATA_ITEM_KEY ||
+ (key.type == BTRFS_EXTENT_ITEM_KEY &&
+ key.offset == blocksize)))
+ ret = 0;
+ }
+
+ if (ret) {
+ skinny = false;
+ btrfs_release_path(path);
+ goto again;
+ }
+ }
+ if (ret) {
+ ASSERT(ret == 1);
+ btrfs_print_leaf(path->nodes[0]);
+ btrfs_err(fs_info,
+ "tree block extent item (%llu) is not found in extent tree",
+ bytenr);
+ WARN_ON(1);
+ ret = -EINVAL;
+ goto out;
+ }
+
+ ret = add_tree_block(rc, &key, path, blocks);
+out:
+ btrfs_free_path(path);
+ return ret;
+}
+
+/*
+ * helper to check if the block use full backrefs for pointers in it
+ */
+static int block_use_full_backref(struct reloc_control *rc,
+ struct extent_buffer *eb)
+{
+ u64 flags;
+ int ret;
+
+ if (btrfs_header_flag(eb, BTRFS_HEADER_FLAG_RELOC) ||
+ btrfs_header_backref_rev(eb) < BTRFS_MIXED_BACKREF_REV)
+ return 1;
+
+ ret = btrfs_lookup_extent_info(NULL, rc->extent_root->fs_info,
+ eb->start, btrfs_header_level(eb), 1,
+ NULL, &flags);
+ BUG_ON(ret);
+
+ if (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF)
+ ret = 1;
+ else
+ ret = 0;
+ return ret;
+}
+
+static int delete_block_group_cache(struct btrfs_fs_info *fs_info,
+ struct btrfs_block_group_cache *block_group,
+ struct inode *inode,
+ u64 ino)
+{
+ struct btrfs_key key;
+ struct btrfs_root *root = fs_info->tree_root;
+ struct btrfs_trans_handle *trans;
+ int ret = 0;
+
+ if (inode)
+ goto truncate;
+
+ key.objectid = ino;
+ key.type = BTRFS_INODE_ITEM_KEY;
+ key.offset = 0;
+
+ inode = btrfs_iget(fs_info->sb, &key, root, NULL);
+ if (IS_ERR(inode))
+ return -ENOENT;
+
+truncate:
+ ret = btrfs_check_trunc_cache_free_space(fs_info,
+ &fs_info->global_block_rsv);
+ if (ret)
+ goto out;
+
+ trans = btrfs_join_transaction(root);
+ if (IS_ERR(trans)) {
+ ret = PTR_ERR(trans);
+ goto out;
+ }
+
+ ret = btrfs_truncate_free_space_cache(trans, block_group, inode);
+
+ btrfs_end_transaction(trans);
+ btrfs_btree_balance_dirty(fs_info);
+out:
+ iput(inode);
+ 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_fs_info *fs_info = rc->extent_root->fs_info;
+ struct btrfs_path *path;
+ struct tree_block *block;
+ struct btrfs_root *root;
+ struct btrfs_file_extent_item *fi;
+ struct rb_node *rb_node;
+ struct btrfs_key key;
+ u64 ref_root;
+ u64 ref_objectid;
+ u64 ref_offset;
+ u32 ref_count;
+ u32 nritems;
+ int err = 0;
+ int added = 0;
+ int counted;
+ int ret;
+
+ ref_root = btrfs_extent_data_ref_root(leaf, ref);
+ ref_objectid = btrfs_extent_data_ref_objectid(leaf, ref);
+ ref_offset = btrfs_extent_data_ref_offset(leaf, ref);
+ ref_count = btrfs_extent_data_ref_count(leaf, ref);
+
+ /*
+ * This is an extent belonging to the free space cache, lets just delete
+ * it and redo the search.
+ */
+ if (ref_root == BTRFS_ROOT_TREE_OBJECTID) {
+ ret = delete_block_group_cache(fs_info, rc->block_group,
+ NULL, ref_objectid);
+ if (ret != -ENOENT)
+ return ret;
+ ret = 0;
+ }
+
+ path = btrfs_alloc_path();
+ if (!path)
+ return -ENOMEM;
+ path->reada = READA_FORWARD;
+
+ root = read_fs_root(fs_info, ref_root);
+ if (IS_ERR(root)) {
+ err = PTR_ERR(root);
+ goto out;
+ }
+
+ key.objectid = ref_objectid;
+ key.type = BTRFS_EXTENT_DATA_KEY;
+ if (ref_offset > ((u64)-1 << 32))
+ key.offset = 0;
+ else
+ key.offset = ref_offset;
+
+ 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 (WARN_ON(ret > 0))
+ 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 (WARN_ON(key.objectid != ref_objectid ||
+ key.type != BTRFS_EXTENT_DATA_KEY))
+ 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, 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);
+ if (rb_node)
+ backref_tree_panic(rb_node, -EEXIST,
+ block->bytenr);
+ }
+ if (counted)
+ added = 1;
+ else
+ path->slots[0] = nritems;
+next:
+ path->slots[0]++;
+
+ }
+out:
+ btrfs_free_path(path);
+ return err;
+}
+
+/*
+ * helper 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 = rc->extent_root->fs_info->nodesize;
+ int ret = 0;
+ int err = 0;
+
+ eb = path->nodes[0];
+ ptr = btrfs_item_ptr_offset(eb, path->slots[0]);
+ end = ptr + btrfs_item_size_nr(eb, path->slots[0]);
+ ptr += sizeof(struct btrfs_extent_item);
+
+ while (ptr < end) {
+ iref = (struct btrfs_extent_inline_ref *)ptr;
+ key.type = btrfs_get_extent_inline_ref_type(eb, iref,
+ BTRFS_REF_TYPE_DATA);
+ 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 {
+ ret = -EUCLEAN;
+ btrfs_err(rc->extent_root->fs_info,
+ "extent %llu slot %d has an invalid inline ref type",
+ eb->start, path->slots[0]);
+ }
+ if (ret) {
+ err = ret;
+ goto out;
+ }
+ 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;
+
+ if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
+ 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 if (unlikely(key.type == BTRFS_EXTENT_REF_V0_KEY)) {
+ btrfs_print_v0_err(eb->fs_info);
+ btrfs_handle_fs_error(eb->fs_info, -EINVAL, NULL);
+ ret = -EINVAL;
+ } else {
+ ret = 0;
+ }
+ if (ret) {
+ err = ret;
+ break;
+ }
+ path->slots[0]++;
+ }
+out:
+ btrfs_release_path(path);
+ if (err)
+ free_block_list(blocks);
+ return err;
+}
+
+/*
+ * helper to find next unprocessed extent
+ */
+static noinline_for_stack
+int find_next_extent(struct reloc_control *rc, struct btrfs_path *path,
+ struct btrfs_key *extent_key)
+{
+ struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
+ 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.type != BTRFS_METADATA_ITEM_KEY) {
+ path->slots[0]++;
+ goto next;
+ }
+
+ if (key.type == BTRFS_EXTENT_ITEM_KEY &&
+ key.objectid + key.offset <= rc->search_start) {
+ path->slots[0]++;
+ goto next;
+ }
+
+ if (key.type == BTRFS_METADATA_ITEM_KEY &&
+ key.objectid + fs_info->nodesize <=
+ rc->search_start) {
+ path->slots[0]++;
+ goto next;
+ }
+
+ ret = find_first_extent_bit(&rc->processed_blocks,
+ key.objectid, &start, &end,
+ EXTENT_DIRTY, NULL);
+
+ if (ret == 0 && start <= key.objectid) {
+ btrfs_release_path(path);
+ rc->search_start = end + 1;
+ } else {
+ if (key.type == BTRFS_EXTENT_ITEM_KEY)
+ rc->search_start = key.objectid + key.offset;
+ else
+ rc->search_start = key.objectid +
+ fs_info->nodesize;
+ memcpy(extent_key, &key, sizeof(key));
+ return 0;
+ }
+ }
+ btrfs_release_path(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->reloc_mutex);
+ fs_info->reloc_ctl = rc;
+ mutex_unlock(&fs_info->reloc_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->reloc_mutex);
+ fs_info->reloc_ctl = NULL;
+ mutex_unlock(&fs_info->reloc_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;
+}
+
+static noinline_for_stack
+int prepare_to_relocate(struct reloc_control *rc)
+{
+ struct btrfs_trans_handle *trans;
+ int ret;
+
+ rc->block_rsv = btrfs_alloc_block_rsv(rc->extent_root->fs_info,
+ BTRFS_BLOCK_RSV_TEMP);
+ if (!rc->block_rsv)
+ return -ENOMEM;
+
+ memset(&rc->cluster, 0, sizeof(rc->cluster));
+ rc->search_start = rc->block_group->key.objectid;
+ rc->extents_found = 0;
+ rc->nodes_relocated = 0;
+ rc->merging_rsv_size = 0;
+ rc->reserved_bytes = 0;
+ rc->block_rsv->size = rc->extent_root->fs_info->nodesize *
+ RELOCATION_RESERVED_NODES;
+ ret = btrfs_block_rsv_refill(rc->extent_root,
+ rc->block_rsv, rc->block_rsv->size,
+ BTRFS_RESERVE_FLUSH_ALL);
+ if (ret)
+ return ret;
+
+ rc->create_reloc_tree = 1;
+ set_reloc_control(rc);
+
+ trans = btrfs_join_transaction(rc->extent_root);
+ if (IS_ERR(trans)) {
+ unset_reloc_control(rc);
+ /*
+ * extent tree is not a ref_cow tree and has no reloc_root to
+ * cleanup. And callers are responsible to free the above
+ * block rsv.
+ */
+ return PTR_ERR(trans);
+ }
+ btrfs_commit_transaction(trans);
+ return 0;
+}
+
+static noinline_for_stack int relocate_block_group(struct reloc_control *rc)
+{
+ struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
+ struct rb_root blocks = RB_ROOT;
+ struct btrfs_key key;
+ struct btrfs_trans_handle *trans = NULL;
+ struct btrfs_path *path;
+ struct btrfs_extent_item *ei;
+ u64 flags;
+ u32 item_size;
+ int ret;
+ int err = 0;
+ int progress = 0;
+
+ path = btrfs_alloc_path();
+ if (!path)
+ return -ENOMEM;
+ path->reada = READA_FORWARD;
+
+ ret = prepare_to_relocate(rc);
+ if (ret) {
+ err = ret;
+ goto out_free;
+ }
+
+ while (1) {
+ rc->reserved_bytes = 0;
+ ret = btrfs_block_rsv_refill(rc->extent_root,
+ rc->block_rsv, rc->block_rsv->size,
+ BTRFS_RESERVE_FLUSH_ALL);
+ if (ret) {
+ err = ret;
+ break;
+ }
+ progress++;
+ trans = btrfs_start_transaction(rc->extent_root, 0);
+ if (IS_ERR(trans)) {
+ err = PTR_ERR(trans);
+ trans = NULL;
+ break;
+ }
+restart:
+ if (update_backref_cache(trans, &rc->backref_cache)) {
+ btrfs_end_transaction(trans);
+ trans = NULL;
+ continue;
+ }
+
+ ret = find_next_extent(rc, path, &key);
+ 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);
+ 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 if (unlikely(item_size == sizeof(struct btrfs_extent_item_v0))) {
+ err = -EINVAL;
+ btrfs_print_v0_err(trans->fs_info);
+ btrfs_abort_transaction(trans, err);
+ break;
+ } else {
+ BUG();
+ }
+
+ 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(path);
+ ret = 0;
+ }
+ if (ret < 0) {
+ err = ret;
+ break;
+ }
+
+ if (!RB_EMPTY_ROOT(&blocks)) {
+ ret = relocate_tree_blocks(trans, rc, &blocks);
+ if (ret < 0) {
+ /*
+ * if we fail to relocate tree blocks, force to update
+ * backref cache when committing transaction.
+ */
+ rc->backref_cache.last_trans = trans->transid - 1;
+
+ if (ret != -EAGAIN) {
+ err = ret;
+ break;
+ }
+ rc->extents_found--;
+ rc->search_start = key.objectid;
+ }
+ }
+
+ btrfs_end_transaction_throttle(trans);
+ btrfs_btree_balance_dirty(fs_info);
+ trans = NULL;
+
+ if (rc->stage == MOVE_DATA_EXTENTS &&
+ (flags & BTRFS_EXTENT_FLAG_DATA)) {
+ rc->found_file_extent = 1;
+ ret = relocate_data_extent(rc->data_inode,
+ &key, &rc->cluster);
+ if (ret < 0) {
+ err = ret;
+ break;
+ }
+ }
+ }
+ if (trans && progress && err == -ENOSPC) {
+ ret = btrfs_force_chunk_alloc(trans, rc->block_group->flags);
+ if (ret == 1) {
+ err = 0;
+ progress = 0;
+ goto restart;
+ }
+ }
+
+ btrfs_release_path(path);
+ clear_extent_bits(&rc->processed_blocks, 0, (u64)-1, EXTENT_DIRTY);
+
+ if (trans) {
+ btrfs_end_transaction_throttle(trans);
+ btrfs_btree_balance_dirty(fs_info);
+ }
+
+ if (!err) {
+ ret = relocate_file_extent_cluster(rc->data_inode,
+ &rc->cluster);
+ if (ret < 0)
+ err = ret;
+ }
+
+ rc->create_reloc_tree = 0;
+ set_reloc_control(rc);
+
+ backref_cache_cleanup(&rc->backref_cache);
+ btrfs_block_rsv_release(fs_info, rc->block_rsv, (u64)-1);
+
+ err = prepare_to_merge(rc, err);
+
+ merge_reloc_roots(rc);
+
+ rc->merge_reloc_tree = 0;
+ unset_reloc_control(rc);
+ btrfs_block_rsv_release(fs_info, rc->block_rsv, (u64)-1);
+
+ /* get rid of pinned extents */
+ trans = btrfs_join_transaction(rc->extent_root);
+ if (IS_ERR(trans)) {
+ err = PTR_ERR(trans);
+ goto out_free;
+ }
+ btrfs_commit_transaction(trans);
+out_free:
+ btrfs_free_block_rsv(fs_info, rc->block_rsv);
+ btrfs_free_path(path);
+ return err;
+}
+
+static int __insert_orphan_inode(struct btrfs_trans_handle *trans,
+ struct btrfs_root *root, u64 objectid)
+{
+ 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);
+ memzero_extent_buffer(leaf, (unsigned long)item, sizeof(*item));
+ btrfs_set_inode_generation(leaf, item, 1);
+ btrfs_set_inode_size(leaf, item, 0);
+ btrfs_set_inode_mode(leaf, item, S_IFREG | 0600);
+ btrfs_set_inode_flags(leaf, item, BTRFS_INODE_NOCOMPRESS |
+ BTRFS_INODE_PREALLOC);
+ btrfs_mark_buffer_dirty(leaf);
+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 noinline_for_stack
+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;
+ u64 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, 6);
+ if (IS_ERR(trans))
+ return ERR_CAST(trans);
+
+ err = btrfs_find_free_objectid(root, &objectid);
+ if (err)
+ goto out;
+
+ err = __insert_orphan_inode(trans, root, objectid);
+ BUG_ON(err);
+
+ key.objectid = objectid;
+ key.type = BTRFS_INODE_ITEM_KEY;
+ key.offset = 0;
+ inode = btrfs_iget(fs_info->sb, &key, root, NULL);
+ BUG_ON(IS_ERR(inode));
+ BTRFS_I(inode)->index_cnt = group->key.objectid;
+
+ err = btrfs_orphan_add(trans, BTRFS_I(inode));
+out:
+ btrfs_end_transaction(trans);
+ btrfs_btree_balance_dirty(fs_info);
+ if (err) {
+ if (inode)
+ iput(inode);
+ inode = ERR_PTR(err);
+ }
+ return inode;
+}
+
+static struct reloc_control *alloc_reloc_control(void)
+{
+ struct reloc_control *rc;
+
+ rc = kzalloc(sizeof(*rc), GFP_NOFS);
+ if (!rc)
+ return NULL;
+
+ INIT_LIST_HEAD(&rc->reloc_roots);
+ backref_cache_init(&rc->backref_cache);
+ mapping_tree_init(&rc->reloc_root_tree);
+ extent_io_tree_init(&rc->processed_blocks, NULL);
+ return rc;
+}
+
+/*
+ * Print the block group being relocated
+ */
+static void describe_relocation(struct btrfs_fs_info *fs_info,
+ struct btrfs_block_group_cache *block_group)
+{
+ char buf[128]; /* prefixed by a '|' that'll be dropped */
+ u64 flags = block_group->flags;
+
+ /* Shouldn't happen */
+ if (!flags) {
+ strcpy(buf, "|NONE");
+ } else {
+ char *bp = buf;
+
+#define DESCRIBE_FLAG(f, d) \
+ if (flags & BTRFS_BLOCK_GROUP_##f) { \
+ bp += snprintf(bp, buf - bp + sizeof(buf), "|%s", d); \
+ flags &= ~BTRFS_BLOCK_GROUP_##f; \
+ }
+ DESCRIBE_FLAG(DATA, "data");
+ DESCRIBE_FLAG(SYSTEM, "system");
+ DESCRIBE_FLAG(METADATA, "metadata");
+ DESCRIBE_FLAG(RAID0, "raid0");
+ DESCRIBE_FLAG(RAID1, "raid1");
+ DESCRIBE_FLAG(DUP, "dup");
+ DESCRIBE_FLAG(RAID10, "raid10");
+ DESCRIBE_FLAG(RAID5, "raid5");
+ DESCRIBE_FLAG(RAID6, "raid6");
+ if (flags)
+ snprintf(bp, buf - bp + sizeof(buf), "|0x%llx", flags);
+#undef DESCRIBE_FLAG
+ }
+
+ btrfs_info(fs_info,
+ "relocating block group %llu flags %s",
+ block_group->key.objectid, buf + 1);
+}
+
+/*
+ * function to relocate all extents in a block group.
+ */
+int btrfs_relocate_block_group(struct btrfs_fs_info *fs_info, u64 group_start)
+{
+ struct btrfs_root *extent_root = fs_info->extent_root;
+ struct reloc_control *rc;
+ struct inode *inode;
+ struct btrfs_path *path;
+ int ret;
+ int rw = 0;
+ int err = 0;
+
+ rc = alloc_reloc_control();
+ if (!rc)
+ return -ENOMEM;
+
+ rc->extent_root = extent_root;
+
+ rc->block_group = btrfs_lookup_block_group(fs_info, group_start);
+ BUG_ON(!rc->block_group);
+
+ ret = btrfs_inc_block_group_ro(rc->block_group);
+ if (ret) {
+ err = ret;
+ goto out;
+ }
+ rw = 1;
+
+ path = btrfs_alloc_path();
+ if (!path) {
+ err = -ENOMEM;
+ goto out;
+ }
+
+ inode = lookup_free_space_inode(fs_info, rc->block_group, path);
+ btrfs_free_path(path);
+
+ if (!IS_ERR(inode))
+ ret = delete_block_group_cache(fs_info, rc->block_group, inode, 0);
+ else
+ ret = PTR_ERR(inode);
+
+ if (ret && ret != -ENOENT) {
+ err = ret;
+ goto out;
+ }
+
+ 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;
+ }
+
+ describe_relocation(fs_info, rc->block_group);
+
+ btrfs_wait_block_group_reservations(rc->block_group);
+ btrfs_wait_nocow_writers(rc->block_group);
+ btrfs_wait_ordered_roots(fs_info, U64_MAX,
+ rc->block_group->key.objectid,
+ rc->block_group->key.offset);
+
+ while (1) {
+ mutex_lock(&fs_info->cleaner_mutex);
+ ret = relocate_block_group(rc);
+ mutex_unlock(&fs_info->cleaner_mutex);
+ if (ret < 0) {
+ err = ret;
+ goto out;
+ }
+
+ if (rc->extents_found == 0)
+ break;
+
+ btrfs_info(fs_info, "found %llu extents", rc->extents_found);
+
+ if (rc->stage == MOVE_DATA_EXTENTS && rc->found_file_extent) {
+ ret = btrfs_wait_ordered_range(rc->data_inode, 0,
+ (u64)-1);
+ if (ret) {
+ err = ret;
+ goto out;
+ }
+ invalidate_mapping_pages(rc->data_inode->i_mapping,
+ 0, -1);
+ rc->stage = UPDATE_DATA_PTRS;
+ }
+ }
+
+ 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:
+ if (err && rw)
+ btrfs_dec_block_group_ro(rc->block_group);
+ iput(rc->data_inode);
+ btrfs_put_block_group(rc->block_group);
+ kfree(rc);
+ return err;
+}
+
+static noinline_for_stack int mark_garbage_root(struct btrfs_root *root)
+{
+ struct btrfs_fs_info *fs_info = root->fs_info;
+ struct btrfs_trans_handle *trans;
+ int ret, err;
+
+ trans = btrfs_start_transaction(fs_info->tree_root, 0);
+ if (IS_ERR(trans))
+ return PTR_ERR(trans);
+
+ 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, fs_info->tree_root,
+ &root->root_key, &root->root_item);
+
+ err = btrfs_end_transaction(trans);
+ if (err)
+ return err;
+ return ret;
+}
+
+/*
+ * 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)
+{
+ struct btrfs_fs_info *fs_info = root->fs_info;
+ 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;
+ path->reada = READA_BACK;
+
+ key.objectid = BTRFS_TREE_RELOC_OBJECTID;
+ key.type = BTRFS_ROOT_ITEM_KEY;
+ key.offset = (u64)-1;
+
+ while (1) {
+ ret = btrfs_search_slot(NULL, 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(path);
+
+ if (key.objectid != BTRFS_TREE_RELOC_OBJECTID ||
+ key.type != BTRFS_ROOT_ITEM_KEY)
+ break;
+
+ reloc_root = btrfs_read_fs_root(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(fs_info,
+ reloc_root->root_key.offset);
+ if (IS_ERR(fs_root)) {
+ ret = PTR_ERR(fs_root);
+ if (ret != -ENOENT) {
+ err = ret;
+ goto out;
+ }
+ ret = mark_garbage_root(reloc_root);
+ if (ret < 0) {
+ err = ret;
+ goto out;
+ }
+ }
+ }
+
+ if (key.offset == 0)
+ break;
+
+ key.offset--;
+ }
+ btrfs_release_path(path);
+
+ if (list_empty(&reloc_roots))
+ goto out;
+
+ rc = alloc_reloc_control();
+ if (!rc) {
+ err = -ENOMEM;
+ goto out;
+ }
+
+ rc->extent_root = fs_info->extent_root;
+
+ set_reloc_control(rc);
+
+ trans = btrfs_join_transaction(rc->extent_root);
+ if (IS_ERR(trans)) {
+ unset_reloc_control(rc);
+ err = PTR_ERR(trans);
+ goto out_free;
+ }
+
+ rc->merge_reloc_tree = 1;
+
+ 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(fs_info, reloc_root->root_key.offset);
+ if (IS_ERR(fs_root)) {
+ err = PTR_ERR(fs_root);
+ goto out_free;
+ }
+
+ err = __add_reloc_root(reloc_root);
+ BUG_ON(err < 0); /* -ENOMEM or logic error */
+ fs_root->reloc_root = reloc_root;
+ }
+
+ err = btrfs_commit_transaction(trans);
+ if (err)
+ goto out_free;
+
+ merge_reloc_roots(rc);
+
+ unset_reloc_control(rc);
+
+ trans = btrfs_join_transaction(rc->extent_root);
+ if (IS_ERR(trans)) {
+ err = PTR_ERR(trans);
+ goto out_free;
+ }
+ err = btrfs_commit_transaction(trans);
+out_free:
+ kfree(rc);
+out:
+ if (!list_empty(&reloc_roots))
+ free_reloc_roots(&reloc_roots);
+
+ btrfs_free_path(path);
+
+ if (err == 0) {
+ /* cleanup orphan inode in data relocation tree */
+ fs_root = read_fs_root(fs_info, BTRFS_DATA_RELOC_TREE_OBJECTID);
+ if (IS_ERR(fs_root))
+ err = PTR_ERR(fs_root);
+ else
+ err = btrfs_orphan_cleanup(fs_root);
+ }
+ 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_fs_info *fs_info = btrfs_sb(inode->i_sb);
+ struct btrfs_ordered_sum *sums;
+ struct btrfs_ordered_extent *ordered;
+ int ret;
+ u64 disk_bytenr;
+ u64 new_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(fs_info->csum_root, disk_bytenr,
+ disk_bytenr + len - 1, &list, 0);
+ if (ret)
+ goto out;
+
+ while (!list_empty(&list)) {
+ sums = list_entry(list.next, struct btrfs_ordered_sum, list);
+ list_del_init(&sums->list);
+
+ /*
+ * We need to offset the new_bytenr based on where the csum is.
+ * We need to do this because we will read in entire prealloc
+ * extents but we may have written to say the middle of the
+ * prealloc extent, so we need to make sure the csum goes with
+ * the right disk offset.
+ *
+ * We can do this because the data reloc inode refers strictly
+ * to the on disk bytes, so we don't have to worry about
+ * disk_len vs real len like with real inodes since it's all
+ * disk length.
+ */
+ new_bytenr = ordered->start + (sums->bytenr - disk_bytenr);
+ sums->bytenr = new_bytenr;
+
+ btrfs_add_ordered_sum(inode, ordered, sums);
+ }
+out:
+ btrfs_put_ordered_extent(ordered);
+ return ret;
+}
+
+int btrfs_reloc_cow_block(struct btrfs_trans_handle *trans,
+ struct btrfs_root *root, struct extent_buffer *buf,
+ struct extent_buffer *cow)
+{
+ struct btrfs_fs_info *fs_info = root->fs_info;
+ struct reloc_control *rc;
+ struct backref_node *node;
+ int first_cow = 0;
+ int level;
+ int ret = 0;
+
+ rc = fs_info->reloc_ctl;
+ if (!rc)
+ return 0;
+
+ BUG_ON(rc->stage == UPDATE_DATA_PTRS &&
+ root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID);
+
+ if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) {
+ if (buf == root->node)
+ __update_reloc_root(root, cow->start);
+ }
+
+ level = btrfs_header_level(buf);
+ if (btrfs_header_generation(buf) <=
+ btrfs_root_last_snapshot(&root->root_item))
+ first_cow = 1;
+
+ if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID &&
+ rc->create_reloc_tree) {
+ WARN_ON(!first_cow && level == 0);
+
+ node = rc->backref_cache.path[level];
+ BUG_ON(node->bytenr != buf->start &&
+ node->new_bytenr != buf->start);
+
+ drop_node_buffer(node);
+ extent_buffer_get(cow);
+ node->eb = cow;
+ node->new_bytenr = cow->start;
+
+ if (!node->pending) {
+ list_move_tail(&node->list,
+ &rc->backref_cache.pending[level]);
+ node->pending = 1;
+ }
+
+ if (first_cow)
+ __mark_block_processed(rc, node);
+
+ if (first_cow && level > 0)
+ rc->nodes_relocated += buf->len;
+ }
+
+ if (level == 0 && first_cow && rc->stage == UPDATE_DATA_PTRS)
+ ret = replace_file_extents(trans, rc, root, cow);
+ return ret;
+}
+
+/*
+ * called before creating snapshot. it calculates metadata reservation
+ * required for relocating tree blocks in the snapshot
+ */
+void btrfs_reloc_pre_snapshot(struct btrfs_pending_snapshot *pending,
+ u64 *bytes_to_reserve)
+{
+ struct btrfs_root *root;
+ struct reloc_control *rc;
+
+ root = pending->root;
+ if (!root->reloc_root)
+ return;
+
+ rc = root->fs_info->reloc_ctl;
+ if (!rc->merge_reloc_tree)
+ return;
+
+ root = root->reloc_root;
+ BUG_ON(btrfs_root_refs(&root->root_item) == 0);
+ /*
+ * relocation is in the stage of merging trees. the space
+ * used by merging a reloc tree is twice the size of
+ * relocated tree nodes in the worst case. half for cowing
+ * the reloc tree, half for cowing the fs tree. the space
+ * used by cowing the reloc tree will be freed after the
+ * tree is dropped. if we create snapshot, cowing the fs
+ * tree may use more space than it frees. so we need
+ * reserve extra space.
+ */
+ *bytes_to_reserve += rc->nodes_relocated;
+}
+
+/*
+ * called after snapshot is created. migrate block reservation
+ * and create reloc root for the newly created snapshot
+ */
+int btrfs_reloc_post_snapshot(struct btrfs_trans_handle *trans,
+ struct btrfs_pending_snapshot *pending)
+{
+ struct btrfs_root *root = pending->root;
+ struct btrfs_root *reloc_root;
+ struct btrfs_root *new_root;
+ struct reloc_control *rc;
+ int ret;
+
+ if (!root->reloc_root)
+ return 0;
+
+ rc = root->fs_info->reloc_ctl;
+ rc->merging_rsv_size += rc->nodes_relocated;
+
+ if (rc->merge_reloc_tree) {
+ ret = btrfs_block_rsv_migrate(&pending->block_rsv,
+ rc->block_rsv,
+ rc->nodes_relocated, 1);
+ if (ret)
+ return ret;
+ }
+
+ new_root = pending->snap;
+ reloc_root = create_reloc_root(trans, root->reloc_root,
+ new_root->root_key.objectid);
+ if (IS_ERR(reloc_root))
+ return PTR_ERR(reloc_root);
+
+ ret = __add_reloc_root(reloc_root);
+ BUG_ON(ret < 0);
+ new_root->reloc_root = reloc_root;
+
+ if (rc->create_reloc_tree)
+ ret = clone_backref_node(trans, rc, root, reloc_root);
+ return ret;
+}