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-rw-r--r--fs/btrfs/relocation.c3711
1 files changed, 3711 insertions, 0 deletions
diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c
new file mode 100644
index 0000000..b23dc20
--- /dev/null
+++ b/fs/btrfs/relocation.c
@@ -0,0 +1,3711 @@
+/*
+ * Copyright (C) 2009 Oracle. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public
+ * License v2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public
+ * License along with this program; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 021110-1307, USA.
+ */
+
+#include <linux/sched.h>
+#include <linux/pagemap.h>
+#include <linux/writeback.h>
+#include <linux/blkdev.h>
+#include <linux/rbtree.h>
+#include "ctree.h"
+#include "disk-io.h"
+#include "transaction.h"
+#include "volumes.h"
+#include "locking.h"
+#include "btrfs_inode.h"
+#include "async-thread.h"
+
+/*
+ * backref_node, mapping_node and tree_block start with this
+ */
+struct tree_entry {
+ struct rb_node rb_node;
+ u64 bytenr;
+};
+
+/*
+ * present a tree block in the backref cache
+ */
+struct backref_node {
+ struct rb_node rb_node;
+ u64 bytenr;
+ /* objectid tree block owner */
+ u64 owner;
+ /* list of upper level blocks reference this block */
+ struct list_head upper;
+ /* list of child blocks in the cache */
+ struct list_head lower;
+ /* NULL if this node is not tree root */
+ struct btrfs_root *root;
+ /* extent buffer got by COW the block */
+ struct extent_buffer *eb;
+ /* level of tree block */
+ unsigned int level:8;
+ /* 1 if the block is root of old snapshot */
+ unsigned int old_root:1;
+ /* 1 if no child blocks in the cache */
+ unsigned int lowest:1;
+ /* is the extent buffer locked */
+ unsigned int locked:1;
+ /* has the block been processed */
+ unsigned int processed:1;
+ /* have backrefs of this block been checked */
+ unsigned int checked:1;
+};
+
+/*
+ * present a block pointer in the backref cache
+ */
+struct backref_edge {
+ struct list_head list[2];
+ struct backref_node *node[2];
+ u64 blockptr;
+};
+
+#define LOWER 0
+#define UPPER 1
+
+struct backref_cache {
+ /* red black tree of all backref nodes in the cache */
+ struct rb_root rb_root;
+ /* list of backref nodes with no child block in the cache */
+ struct list_head pending[BTRFS_MAX_LEVEL];
+ spinlock_t lock;
+};
+
+/*
+ * map address of tree root to tree
+ */
+struct mapping_node {
+ struct rb_node rb_node;
+ u64 bytenr;
+ void *data;
+};
+
+struct mapping_tree {
+ struct rb_root rb_root;
+ spinlock_t lock;
+};
+
+/*
+ * present a tree block to process
+ */
+struct tree_block {
+ struct rb_node rb_node;
+ u64 bytenr;
+ struct btrfs_key key;
+ unsigned int level:8;
+ unsigned int key_ready:1;
+};
+
+/* inode vector */
+#define INODEVEC_SIZE 16
+
+struct inodevec {
+ struct list_head list;
+ struct inode *inode[INODEVEC_SIZE];
+ int nr;
+};
+
+struct reloc_control {
+ /* block group to relocate */
+ struct btrfs_block_group_cache *block_group;
+ /* extent tree */
+ struct btrfs_root *extent_root;
+ /* inode for moving data */
+ struct inode *data_inode;
+ struct btrfs_workers workers;
+ /* tree blocks have been processed */
+ struct extent_io_tree processed_blocks;
+ /* map start of tree root to corresponding reloc tree */
+ struct mapping_tree reloc_root_tree;
+ /* list of reloc trees */
+ struct list_head reloc_roots;
+ u64 search_start;
+ u64 extents_found;
+ u64 extents_skipped;
+ int stage;
+ int create_reloc_root;
+ unsigned int found_file_extent:1;
+ unsigned int found_old_snapshot:1;
+};
+
+/* stages of data relocation */
+#define MOVE_DATA_EXTENTS 0
+#define UPDATE_DATA_PTRS 1
+
+/*
+ * merge reloc tree to corresponding fs tree in worker threads
+ */
+struct async_merge {
+ struct btrfs_work work;
+ struct reloc_control *rc;
+ struct btrfs_root *root;
+ struct completion *done;
+ atomic_t *num_pending;
+};
+
+static void mapping_tree_init(struct mapping_tree *tree)
+{
+ tree->rb_root.rb_node = NULL;
+ spin_lock_init(&tree->lock);
+}
+
+static void backref_cache_init(struct backref_cache *cache)
+{
+ int i;
+ cache->rb_root.rb_node = NULL;
+ for (i = 0; i < BTRFS_MAX_LEVEL; i++)
+ INIT_LIST_HEAD(&cache->pending[i]);
+ spin_lock_init(&cache->lock);
+}
+
+static void backref_node_init(struct backref_node *node)
+{
+ memset(node, 0, sizeof(*node));
+ INIT_LIST_HEAD(&node->upper);
+ INIT_LIST_HEAD(&node->lower);
+ RB_CLEAR_NODE(&node->rb_node);
+}
+
+static struct rb_node *tree_insert(struct rb_root *root, u64 bytenr,
+ struct rb_node *node)
+{
+ struct rb_node **p = &root->rb_node;
+ struct rb_node *parent = NULL;
+ struct tree_entry *entry;
+
+ while (*p) {
+ parent = *p;
+ entry = rb_entry(parent, struct tree_entry, rb_node);
+
+ if (bytenr < entry->bytenr)
+ p = &(*p)->rb_left;
+ else if (bytenr > entry->bytenr)
+ p = &(*p)->rb_right;
+ else
+ return parent;
+ }
+
+ rb_link_node(node, parent, p);
+ rb_insert_color(node, root);
+ return NULL;
+}
+
+static struct rb_node *tree_search(struct rb_root *root, u64 bytenr)
+{
+ struct rb_node *n = root->rb_node;
+ struct tree_entry *entry;
+
+ while (n) {
+ entry = rb_entry(n, struct tree_entry, rb_node);
+
+ if (bytenr < entry->bytenr)
+ n = n->rb_left;
+ else if (bytenr > entry->bytenr)
+ n = n->rb_right;
+ else
+ return n;
+ }
+ return NULL;
+}
+
+/*
+ * walk up backref nodes until reach node presents tree root
+ */
+static struct backref_node *walk_up_backref(struct backref_node *node,
+ struct backref_edge *edges[],
+ int *index)
+{
+ struct backref_edge *edge;
+ int idx = *index;
+
+ while (!list_empty(&node->upper)) {
+ edge = list_entry(node->upper.next,
+ struct backref_edge, list[LOWER]);
+ edges[idx++] = edge;
+ node = edge->node[UPPER];
+ }
+ *index = idx;
+ return node;
+}
+
+/*
+ * walk down backref nodes to find start of next reference path
+ */
+static struct backref_node *walk_down_backref(struct backref_edge *edges[],
+ int *index)
+{
+ struct backref_edge *edge;
+ struct backref_node *lower;
+ int idx = *index;
+
+ while (idx > 0) {
+ edge = edges[idx - 1];
+ lower = edge->node[LOWER];
+ if (list_is_last(&edge->list[LOWER], &lower->upper)) {
+ idx--;
+ continue;
+ }
+ edge = list_entry(edge->list[LOWER].next,
+ struct backref_edge, list[LOWER]);
+ edges[idx - 1] = edge;
+ *index = idx;
+ return edge->node[UPPER];
+ }
+ *index = 0;
+ return NULL;
+}
+
+static void drop_node_buffer(struct backref_node *node)
+{
+ if (node->eb) {
+ if (node->locked) {
+ btrfs_tree_unlock(node->eb);
+ node->locked = 0;
+ }
+ free_extent_buffer(node->eb);
+ node->eb = NULL;
+ }
+}
+
+static void drop_backref_node(struct backref_cache *tree,
+ struct backref_node *node)
+{
+ BUG_ON(!node->lowest);
+ BUG_ON(!list_empty(&node->upper));
+
+ drop_node_buffer(node);
+ list_del(&node->lower);
+
+ rb_erase(&node->rb_node, &tree->rb_root);
+ kfree(node);
+}
+
+/*
+ * remove a backref node from the backref cache
+ */
+static void remove_backref_node(struct backref_cache *cache,
+ struct backref_node *node)
+{
+ struct backref_node *upper;
+ struct backref_edge *edge;
+
+ if (!node)
+ return;
+
+ BUG_ON(!node->lowest);
+ while (!list_empty(&node->upper)) {
+ edge = list_entry(node->upper.next, struct backref_edge,
+ list[LOWER]);
+ upper = edge->node[UPPER];
+ list_del(&edge->list[LOWER]);
+ list_del(&edge->list[UPPER]);
+ kfree(edge);
+ /*
+ * add the node to pending list if no other
+ * child block cached.
+ */
+ if (list_empty(&upper->lower)) {
+ list_add_tail(&upper->lower,
+ &cache->pending[upper->level]);
+ upper->lowest = 1;
+ }
+ }
+ drop_backref_node(cache, node);
+}
+
+/*
+ * find reloc tree by address of tree root
+ */
+static struct btrfs_root *find_reloc_root(struct reloc_control *rc,
+ u64 bytenr)
+{
+ struct rb_node *rb_node;
+ struct mapping_node *node;
+ struct btrfs_root *root = NULL;
+
+ spin_lock(&rc->reloc_root_tree.lock);
+ rb_node = tree_search(&rc->reloc_root_tree.rb_root, bytenr);
+ if (rb_node) {
+ node = rb_entry(rb_node, struct mapping_node, rb_node);
+ root = (struct btrfs_root *)node->data;
+ }
+ spin_unlock(&rc->reloc_root_tree.lock);
+ return root;
+}
+
+static int is_cowonly_root(u64 root_objectid)
+{
+ if (root_objectid == BTRFS_ROOT_TREE_OBJECTID ||
+ root_objectid == BTRFS_EXTENT_TREE_OBJECTID ||
+ root_objectid == BTRFS_CHUNK_TREE_OBJECTID ||
+ root_objectid == BTRFS_DEV_TREE_OBJECTID ||
+ root_objectid == BTRFS_TREE_LOG_OBJECTID ||
+ root_objectid == BTRFS_CSUM_TREE_OBJECTID)
+ return 1;
+ return 0;
+}
+
+static struct btrfs_root *read_fs_root(struct btrfs_fs_info *fs_info,
+ u64 root_objectid)
+{
+ struct btrfs_key key;
+
+ key.objectid = root_objectid;
+ key.type = BTRFS_ROOT_ITEM_KEY;
+ if (is_cowonly_root(root_objectid))
+ key.offset = 0;
+ else
+ key.offset = (u64)-1;
+
+ return btrfs_read_fs_root_no_name(fs_info, &key);
+}
+
+#ifdef BTRFS_COMPAT_EXTENT_TREE_V0
+static noinline_for_stack
+struct btrfs_root *find_tree_root(struct reloc_control *rc,
+ struct extent_buffer *leaf,
+ struct btrfs_extent_ref_v0 *ref0)
+{
+ struct btrfs_root *root;
+ u64 root_objectid = btrfs_ref_root_v0(leaf, ref0);
+ u64 generation = btrfs_ref_generation_v0(leaf, ref0);
+
+ BUG_ON(root_objectid == BTRFS_TREE_RELOC_OBJECTID);
+
+ root = read_fs_root(rc->extent_root->fs_info, root_objectid);
+ BUG_ON(IS_ERR(root));
+
+ if (root->ref_cows &&
+ generation != btrfs_root_generation(&root->root_item))
+ return NULL;
+
+ return root;
+}
+#endif
+
+static noinline_for_stack
+int find_inline_backref(struct extent_buffer *leaf, int slot,
+ unsigned long *ptr, unsigned long *end)
+{
+ struct btrfs_extent_item *ei;
+ struct btrfs_tree_block_info *bi;
+ u32 item_size;
+
+ item_size = btrfs_item_size_nr(leaf, slot);
+#ifdef BTRFS_COMPAT_EXTENT_TREE_V0
+ if (item_size < sizeof(*ei)) {
+ WARN_ON(item_size != sizeof(struct btrfs_extent_item_v0));
+ return 1;
+ }
+#endif
+ ei = btrfs_item_ptr(leaf, slot, struct btrfs_extent_item);
+ WARN_ON(!(btrfs_extent_flags(leaf, ei) &
+ BTRFS_EXTENT_FLAG_TREE_BLOCK));
+
+ if (item_size <= sizeof(*ei) + sizeof(*bi)) {
+ WARN_ON(item_size < sizeof(*ei) + sizeof(*bi));
+ return 1;
+ }
+
+ bi = (struct btrfs_tree_block_info *)(ei + 1);
+ *ptr = (unsigned long)(bi + 1);
+ *end = (unsigned long)ei + item_size;
+ return 0;
+}
+
+/*
+ * build backref tree for a given tree block. root of the backref tree
+ * corresponds the tree block, leaves of the backref tree correspond
+ * roots of b-trees that reference the tree block.
+ *
+ * the basic idea of this function is check backrefs of a given block
+ * to find upper level blocks that refernece the block, and then check
+ * bakcrefs of these upper level blocks recursively. the recursion stop
+ * when tree root is reached or backrefs for the block is cached.
+ *
+ * NOTE: if we find backrefs for a block are cached, we know backrefs
+ * for all upper level blocks that directly/indirectly reference the
+ * block are also cached.
+ */
+static struct backref_node *build_backref_tree(struct reloc_control *rc,
+ struct backref_cache *cache,
+ struct btrfs_key *node_key,
+ int level, u64 bytenr)
+{
+ struct btrfs_path *path1;
+ struct btrfs_path *path2;
+ struct extent_buffer *eb;
+ struct btrfs_root *root;
+ struct backref_node *cur;
+ struct backref_node *upper;
+ struct backref_node *lower;
+ struct backref_node *node = NULL;
+ struct backref_node *exist = NULL;
+ struct backref_edge *edge;
+ struct rb_node *rb_node;
+ struct btrfs_key key;
+ unsigned long end;
+ unsigned long ptr;
+ LIST_HEAD(list);
+ int ret;
+ int err = 0;
+
+ path1 = btrfs_alloc_path();
+ path2 = btrfs_alloc_path();
+ if (!path1 || !path2) {
+ err = -ENOMEM;
+ goto out;
+ }
+
+ node = kmalloc(sizeof(*node), GFP_NOFS);
+ if (!node) {
+ err = -ENOMEM;
+ goto out;
+ }
+
+ backref_node_init(node);
+ node->bytenr = bytenr;
+ node->owner = 0;
+ node->level = level;
+ node->lowest = 1;
+ cur = node;
+again:
+ end = 0;
+ ptr = 0;
+ key.objectid = cur->bytenr;
+ key.type = BTRFS_EXTENT_ITEM_KEY;
+ key.offset = (u64)-1;
+
+ path1->search_commit_root = 1;
+ path1->skip_locking = 1;
+ ret = btrfs_search_slot(NULL, rc->extent_root, &key, path1,
+ 0, 0);
+ if (ret < 0) {
+ err = ret;
+ goto out;
+ }
+ BUG_ON(!ret || !path1->slots[0]);
+
+ path1->slots[0]--;
+
+ WARN_ON(cur->checked);
+ if (!list_empty(&cur->upper)) {
+ /*
+ * the backref was added previously when processsing
+ * backref of type BTRFS_TREE_BLOCK_REF_KEY
+ */
+ BUG_ON(!list_is_singular(&cur->upper));
+ edge = list_entry(cur->upper.next, struct backref_edge,
+ list[LOWER]);
+ BUG_ON(!list_empty(&edge->list[UPPER]));
+ exist = edge->node[UPPER];
+ /*
+ * add the upper level block to pending list if we need
+ * check its backrefs
+ */
+ if (!exist->checked)
+ list_add_tail(&edge->list[UPPER], &list);
+ } else {
+ exist = NULL;
+ }
+
+ while (1) {
+ cond_resched();
+ eb = path1->nodes[0];
+
+ if (ptr >= end) {
+ if (path1->slots[0] >= btrfs_header_nritems(eb)) {
+ ret = btrfs_next_leaf(rc->extent_root, path1);
+ if (ret < 0) {
+ err = ret;
+ goto out;
+ }
+ if (ret > 0)
+ break;
+ eb = path1->nodes[0];
+ }
+
+ btrfs_item_key_to_cpu(eb, &key, path1->slots[0]);
+ if (key.objectid != cur->bytenr) {
+ WARN_ON(exist);
+ break;
+ }
+
+ if (key.type == BTRFS_EXTENT_ITEM_KEY) {
+ ret = find_inline_backref(eb, path1->slots[0],
+ &ptr, &end);
+ if (ret)
+ goto next;
+ }
+ }
+
+ if (ptr < end) {
+ /* update key for inline back ref */
+ struct btrfs_extent_inline_ref *iref;
+ iref = (struct btrfs_extent_inline_ref *)ptr;
+ key.type = btrfs_extent_inline_ref_type(eb, iref);
+ key.offset = btrfs_extent_inline_ref_offset(eb, iref);
+ WARN_ON(key.type != BTRFS_TREE_BLOCK_REF_KEY &&
+ key.type != BTRFS_SHARED_BLOCK_REF_KEY);
+ }
+
+ if (exist &&
+ ((key.type == BTRFS_TREE_BLOCK_REF_KEY &&
+ exist->owner == key.offset) ||
+ (key.type == BTRFS_SHARED_BLOCK_REF_KEY &&
+ exist->bytenr == key.offset))) {
+ exist = NULL;
+ goto next;
+ }
+
+#ifdef BTRFS_COMPAT_EXTENT_TREE_V0
+ if (key.type == BTRFS_SHARED_BLOCK_REF_KEY ||
+ key.type == BTRFS_EXTENT_REF_V0_KEY) {
+ if (key.objectid == key.offset &&
+ key.type == BTRFS_EXTENT_REF_V0_KEY) {
+ struct btrfs_extent_ref_v0 *ref0;
+ ref0 = btrfs_item_ptr(eb, path1->slots[0],
+ struct btrfs_extent_ref_v0);
+ root = find_tree_root(rc, eb, ref0);
+ if (root)
+ cur->root = root;
+ else
+ cur->old_root = 1;
+ break;
+ }
+#else
+ BUG_ON(key.type == BTRFS_EXTENT_REF_V0_KEY);
+ if (key.type == BTRFS_SHARED_BLOCK_REF_KEY) {
+#endif
+ if (key.objectid == key.offset) {
+ /*
+ * only root blocks of reloc trees use
+ * backref of this type.
+ */
+ root = find_reloc_root(rc, cur->bytenr);
+ BUG_ON(!root);
+ cur->root = root;
+ break;
+ }
+
+ edge = kzalloc(sizeof(*edge), GFP_NOFS);
+ if (!edge) {
+ err = -ENOMEM;
+ goto out;
+ }
+ rb_node = tree_search(&cache->rb_root, key.offset);
+ if (!rb_node) {
+ upper = kmalloc(sizeof(*upper), GFP_NOFS);
+ if (!upper) {
+ kfree(edge);
+ err = -ENOMEM;
+ goto out;
+ }
+ backref_node_init(upper);
+ upper->bytenr = key.offset;
+ upper->owner = 0;
+ upper->level = cur->level + 1;
+ /*
+ * backrefs for the upper level block isn't
+ * cached, add the block to pending list
+ */
+ list_add_tail(&edge->list[UPPER], &list);
+ } else {
+ upper = rb_entry(rb_node, struct backref_node,
+ rb_node);
+ INIT_LIST_HEAD(&edge->list[UPPER]);
+ }
+ list_add(&edge->list[LOWER], &cur->upper);
+ edge->node[UPPER] = upper;
+ edge->node[LOWER] = cur;
+
+ goto next;
+ } else if (key.type != BTRFS_TREE_BLOCK_REF_KEY) {
+ goto next;
+ }
+
+ /* key.type == BTRFS_TREE_BLOCK_REF_KEY */
+ root = read_fs_root(rc->extent_root->fs_info, key.offset);
+ if (IS_ERR(root)) {
+ err = PTR_ERR(root);
+ goto out;
+ }
+
+ if (btrfs_root_level(&root->root_item) == cur->level) {
+ /* tree root */
+ BUG_ON(btrfs_root_bytenr(&root->root_item) !=
+ cur->bytenr);
+ cur->root = root;
+ break;
+ }
+
+ level = cur->level + 1;
+
+ /*
+ * searching the tree to find upper level blocks
+ * reference the block.
+ */
+ path2->search_commit_root = 1;
+ path2->skip_locking = 1;
+ path2->lowest_level = level;
+ ret = btrfs_search_slot(NULL, root, node_key, path2, 0, 0);
+ path2->lowest_level = 0;
+ if (ret < 0) {
+ err = ret;
+ goto out;
+ }
+
+ eb = path2->nodes[level];
+ WARN_ON(btrfs_node_blockptr(eb, path2->slots[level]) !=
+ cur->bytenr);
+
+ lower = cur;
+ for (; level < BTRFS_MAX_LEVEL; level++) {
+ if (!path2->nodes[level]) {
+ BUG_ON(btrfs_root_bytenr(&root->root_item) !=
+ lower->bytenr);
+ lower->root = root;
+ break;
+ }
+
+ edge = kzalloc(sizeof(*edge), GFP_NOFS);
+ if (!edge) {
+ err = -ENOMEM;
+ goto out;
+ }
+
+ eb = path2->nodes[level];
+ rb_node = tree_search(&cache->rb_root, eb->start);
+ if (!rb_node) {
+ upper = kmalloc(sizeof(*upper), GFP_NOFS);
+ if (!upper) {
+ kfree(edge);
+ err = -ENOMEM;
+ goto out;
+ }
+ backref_node_init(upper);
+ upper->bytenr = eb->start;
+ upper->owner = btrfs_header_owner(eb);
+ upper->level = lower->level + 1;
+
+ /*
+ * if we know the block isn't shared
+ * we can void checking its backrefs.
+ */
+ if (btrfs_block_can_be_shared(root, eb))
+ upper->checked = 0;
+ else
+ upper->checked = 1;
+
+ /*
+ * add the block to pending list if we
+ * need check its backrefs. only block
+ * at 'cur->level + 1' is added to the
+ * tail of pending list. this guarantees
+ * we check backrefs from lower level
+ * blocks to upper level blocks.
+ */
+ if (!upper->checked &&
+ level == cur->level + 1) {
+ list_add_tail(&edge->list[UPPER],
+ &list);
+ } else
+ INIT_LIST_HEAD(&edge->list[UPPER]);
+ } else {
+ upper = rb_entry(rb_node, struct backref_node,
+ rb_node);
+ BUG_ON(!upper->checked);
+ INIT_LIST_HEAD(&edge->list[UPPER]);
+ }
+ list_add_tail(&edge->list[LOWER], &lower->upper);
+ edge->node[UPPER] = upper;
+ edge->node[LOWER] = lower;
+
+ if (rb_node)
+ break;
+ lower = upper;
+ upper = NULL;
+ }
+ btrfs_release_path(root, path2);
+next:
+ if (ptr < end) {
+ ptr += btrfs_extent_inline_ref_size(key.type);
+ if (ptr >= end) {
+ WARN_ON(ptr > end);
+ ptr = 0;
+ end = 0;
+ }
+ }
+ if (ptr >= end)
+ path1->slots[0]++;
+ }
+ btrfs_release_path(rc->extent_root, path1);
+
+ cur->checked = 1;
+ WARN_ON(exist);
+
+ /* the pending list isn't empty, take the first block to process */
+ if (!list_empty(&list)) {
+ edge = list_entry(list.next, struct backref_edge, list[UPPER]);
+ list_del_init(&edge->list[UPPER]);
+ cur = edge->node[UPPER];
+ goto again;
+ }
+
+ /*
+ * everything goes well, connect backref nodes and insert backref nodes
+ * into the cache.
+ */
+ BUG_ON(!node->checked);
+ rb_node = tree_insert(&cache->rb_root, node->bytenr, &node->rb_node);
+ BUG_ON(rb_node);
+
+ list_for_each_entry(edge, &node->upper, list[LOWER])
+ list_add_tail(&edge->list[UPPER], &list);
+
+ while (!list_empty(&list)) {
+ edge = list_entry(list.next, struct backref_edge, list[UPPER]);
+ list_del_init(&edge->list[UPPER]);
+ upper = edge->node[UPPER];
+
+ if (!RB_EMPTY_NODE(&upper->rb_node)) {
+ if (upper->lowest) {
+ list_del_init(&upper->lower);
+ upper->lowest = 0;
+ }
+
+ list_add_tail(&edge->list[UPPER], &upper->lower);
+ continue;
+ }
+
+ BUG_ON(!upper->checked);
+ rb_node = tree_insert(&cache->rb_root, upper->bytenr,
+ &upper->rb_node);
+ BUG_ON(rb_node);
+
+ list_add_tail(&edge->list[UPPER], &upper->lower);
+
+ list_for_each_entry(edge, &upper->upper, list[LOWER])
+ list_add_tail(&edge->list[UPPER], &list);
+ }
+out:
+ btrfs_free_path(path1);
+ btrfs_free_path(path2);
+ if (err) {
+ INIT_LIST_HEAD(&list);
+ upper = node;
+ while (upper) {
+ if (RB_EMPTY_NODE(&upper->rb_node)) {
+ list_splice_tail(&upper->upper, &list);
+ kfree(upper);
+ }
+
+ if (list_empty(&list))
+ break;
+
+ edge = list_entry(list.next, struct backref_edge,
+ list[LOWER]);
+ upper = edge->node[UPPER];
+ kfree(edge);
+ }
+ return ERR_PTR(err);
+ }
+ return node;
+}
+
+/*
+ * helper to add 'address of tree root -> reloc tree' mapping
+ */
+static int __add_reloc_root(struct btrfs_root *root)
+{
+ struct rb_node *rb_node;
+ struct mapping_node *node;
+ struct reloc_control *rc = root->fs_info->reloc_ctl;
+
+ node = kmalloc(sizeof(*node), GFP_NOFS);
+ BUG_ON(!node);
+
+ node->bytenr = root->node->start;
+ node->data = root;
+
+ spin_lock(&rc->reloc_root_tree.lock);
+ rb_node = tree_insert(&rc->reloc_root_tree.rb_root,
+ node->bytenr, &node->rb_node);
+ spin_unlock(&rc->reloc_root_tree.lock);
+ BUG_ON(rb_node);
+
+ list_add_tail(&root->root_list, &rc->reloc_roots);
+ return 0;
+}
+
+/*
+ * helper to update/delete the 'address of tree root -> reloc tree'
+ * mapping
+ */
+static int __update_reloc_root(struct btrfs_root *root, int del)
+{
+ struct rb_node *rb_node;
+ struct mapping_node *node = NULL;
+ struct reloc_control *rc = root->fs_info->reloc_ctl;
+
+ spin_lock(&rc->reloc_root_tree.lock);
+ rb_node = tree_search(&rc->reloc_root_tree.rb_root,
+ root->commit_root->start);
+ if (rb_node) {
+ node = rb_entry(rb_node, struct mapping_node, rb_node);
+ rb_erase(&node->rb_node, &rc->reloc_root_tree.rb_root);
+ }
+ spin_unlock(&rc->reloc_root_tree.lock);
+
+ BUG_ON((struct btrfs_root *)node->data != root);
+
+ if (!del) {
+ spin_lock(&rc->reloc_root_tree.lock);
+ node->bytenr = root->node->start;
+ rb_node = tree_insert(&rc->reloc_root_tree.rb_root,
+ node->bytenr, &node->rb_node);
+ spin_unlock(&rc->reloc_root_tree.lock);
+ BUG_ON(rb_node);
+ } else {
+ list_del_init(&root->root_list);
+ kfree(node);
+ }
+ return 0;
+}
+
+/*
+ * create reloc tree for a given fs tree. reloc tree is just a
+ * snapshot of the fs tree with special root objectid.
+ */
+int btrfs_init_reloc_root(struct btrfs_trans_handle *trans,
+ struct btrfs_root *root)
+{
+ struct btrfs_root *reloc_root;
+ struct extent_buffer *eb;
+ struct btrfs_root_item *root_item;
+ struct btrfs_key root_key;
+ int ret;
+
+ if (root->reloc_root) {
+ reloc_root = root->reloc_root;
+ reloc_root->last_trans = trans->transid;
+ return 0;
+ }
+
+ if (!root->fs_info->reloc_ctl ||
+ !root->fs_info->reloc_ctl->create_reloc_root ||
+ root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID)
+ return 0;
+
+ root_item = kmalloc(sizeof(*root_item), GFP_NOFS);
+ BUG_ON(!root_item);
+
+ root_key.objectid = BTRFS_TREE_RELOC_OBJECTID;
+ root_key.type = BTRFS_ROOT_ITEM_KEY;
+ root_key.offset = root->root_key.objectid;
+
+ ret = btrfs_copy_root(trans, root, root->commit_root, &eb,
+ BTRFS_TREE_RELOC_OBJECTID);
+ BUG_ON(ret);
+
+ btrfs_set_root_last_snapshot(&root->root_item, trans->transid - 1);
+ memcpy(root_item, &root->root_item, sizeof(*root_item));
+ btrfs_set_root_refs(root_item, 1);
+ btrfs_set_root_bytenr(root_item, eb->start);
+ btrfs_set_root_level(root_item, btrfs_header_level(eb));
+ btrfs_set_root_generation(root_item, trans->transid);
+ memset(&root_item->drop_progress, 0, sizeof(struct btrfs_disk_key));
+ root_item->drop_level = 0;
+
+ btrfs_tree_unlock(eb);
+ free_extent_buffer(eb);
+
+ ret = btrfs_insert_root(trans, root->fs_info->tree_root,
+ &root_key, root_item);
+ BUG_ON(ret);
+ kfree(root_item);
+
+ reloc_root = btrfs_read_fs_root_no_radix(root->fs_info->tree_root,
+ &root_key);
+ BUG_ON(IS_ERR(reloc_root));
+ reloc_root->last_trans = trans->transid;
+
+ __add_reloc_root(reloc_root);
+ root->reloc_root = reloc_root;
+ return 0;
+}
+
+/*
+ * update root item of reloc tree
+ */
+int btrfs_update_reloc_root(struct btrfs_trans_handle *trans,
+ struct btrfs_root *root)
+{
+ struct btrfs_root *reloc_root;
+ struct btrfs_root_item *root_item;
+ int del = 0;
+ int ret;
+
+ if (!root->reloc_root)
+ return 0;
+
+ reloc_root = root->reloc_root;
+ root_item = &reloc_root->root_item;
+
+ if (btrfs_root_refs(root_item) == 0) {
+ root->reloc_root = NULL;
+ del = 1;
+ }
+
+ __update_reloc_root(reloc_root, del);
+
+ if (reloc_root->commit_root != reloc_root->node) {
+ btrfs_set_root_node(root_item, reloc_root->node);
+ free_extent_buffer(reloc_root->commit_root);
+ reloc_root->commit_root = btrfs_root_node(reloc_root);
+ }
+
+ ret = btrfs_update_root(trans, root->fs_info->tree_root,
+ &reloc_root->root_key, root_item);
+ BUG_ON(ret);
+ return 0;
+}
+
+/*
+ * helper to find first cached inode with inode number >= objectid
+ * in a subvolume
+ */
+static struct inode *find_next_inode(struct btrfs_root *root, u64 objectid)
+{
+ struct rb_node *node;
+ struct rb_node *prev;
+ struct btrfs_inode *entry;
+ struct inode *inode;
+
+ spin_lock(&root->inode_lock);
+again:
+ node = root->inode_tree.rb_node;
+ prev = NULL;
+ while (node) {
+ prev = node;
+ entry = rb_entry(node, struct btrfs_inode, rb_node);
+
+ if (objectid < entry->vfs_inode.i_ino)
+ node = node->rb_left;
+ else if (objectid > entry->vfs_inode.i_ino)
+ node = node->rb_right;
+ else
+ break;
+ }
+ if (!node) {
+ while (prev) {
+ entry = rb_entry(prev, struct btrfs_inode, rb_node);
+ if (objectid <= entry->vfs_inode.i_ino) {
+ node = prev;
+ break;
+ }
+ prev = rb_next(prev);
+ }
+ }
+ while (node) {
+ entry = rb_entry(node, struct btrfs_inode, rb_node);
+ inode = igrab(&entry->vfs_inode);
+ if (inode) {
+ spin_unlock(&root->inode_lock);
+ return inode;
+ }
+
+ objectid = entry->vfs_inode.i_ino + 1;
+ if (cond_resched_lock(&root->inode_lock))
+ goto again;
+
+ node = rb_next(node);
+ }
+ spin_unlock(&root->inode_lock);
+ return NULL;
+}
+
+static int in_block_group(u64 bytenr,
+ struct btrfs_block_group_cache *block_group)
+{
+ if (bytenr >= block_group->key.objectid &&
+ bytenr < block_group->key.objectid + block_group->key.offset)
+ return 1;
+ return 0;
+}
+
+/*
+ * get new location of data
+ */
+static int get_new_location(struct inode *reloc_inode, u64 *new_bytenr,
+ u64 bytenr, u64 num_bytes)
+{
+ struct btrfs_root *root = BTRFS_I(reloc_inode)->root;
+ struct btrfs_path *path;
+ struct btrfs_file_extent_item *fi;
+ struct extent_buffer *leaf;
+ int ret;
+
+ path = btrfs_alloc_path();
+ if (!path)
+ return -ENOMEM;
+
+ bytenr -= BTRFS_I(reloc_inode)->index_cnt;
+ ret = btrfs_lookup_file_extent(NULL, root, path, reloc_inode->i_ino,
+ bytenr, 0);
+ if (ret < 0)
+ goto out;
+ if (ret > 0) {
+ ret = -ENOENT;
+ goto out;
+ }
+
+ leaf = path->nodes[0];
+ fi = btrfs_item_ptr(leaf, path->slots[0],
+ struct btrfs_file_extent_item);
+
+ BUG_ON(btrfs_file_extent_offset(leaf, fi) ||
+ btrfs_file_extent_compression(leaf, fi) ||
+ btrfs_file_extent_encryption(leaf, fi) ||
+ btrfs_file_extent_other_encoding(leaf, fi));
+
+ if (num_bytes != btrfs_file_extent_disk_num_bytes(leaf, fi)) {
+ ret = 1;
+ goto out;
+ }
+
+ if (new_bytenr)
+ *new_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
+ ret = 0;
+out:
+ btrfs_free_path(path);
+ return ret;
+}
+
+/*
+ * update file extent items in the tree leaf to point to
+ * the new locations.
+ */
+static int replace_file_extents(struct btrfs_trans_handle *trans,
+ struct reloc_control *rc,
+ struct btrfs_root *root,
+ struct extent_buffer *leaf,
+ struct list_head *inode_list)
+{
+ struct btrfs_key key;
+ struct btrfs_file_extent_item *fi;
+ struct inode *inode = NULL;
+ struct inodevec *ivec = NULL;
+ u64 parent;
+ u64 bytenr;
+ u64 new_bytenr;
+ u64 num_bytes;
+ u64 end;
+ u32 nritems;
+ u32 i;
+ int ret;
+ int first = 1;
+ int dirty = 0;
+
+ if (rc->stage != UPDATE_DATA_PTRS)
+ return 0;
+
+ /* reloc trees always use full backref */
+ if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID)
+ parent = leaf->start;
+ else
+ parent = 0;
+
+ nritems = btrfs_header_nritems(leaf);
+ for (i = 0; i < nritems; i++) {
+ cond_resched();
+ btrfs_item_key_to_cpu(leaf, &key, i);
+ if (key.type != BTRFS_EXTENT_DATA_KEY)
+ continue;
+ fi = btrfs_item_ptr(leaf, i, struct btrfs_file_extent_item);
+ if (btrfs_file_extent_type(leaf, fi) ==
+ BTRFS_FILE_EXTENT_INLINE)
+ continue;
+ bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
+ num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
+ if (bytenr == 0)
+ continue;
+ if (!in_block_group(bytenr, rc->block_group))
+ continue;
+
+ /*
+ * if we are modifying block in fs tree, wait for readpage
+ * to complete and drop the extent cache
+ */
+ if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
+ if (!ivec || ivec->nr == INODEVEC_SIZE) {
+ ivec = kmalloc(sizeof(*ivec), GFP_NOFS);
+ BUG_ON(!ivec);
+ ivec->nr = 0;
+ list_add_tail(&ivec->list, inode_list);
+ }
+ if (first) {
+ inode = find_next_inode(root, key.objectid);
+ if (inode)
+ ivec->inode[ivec->nr++] = inode;
+ first = 0;
+ } else if (inode && inode->i_ino < key.objectid) {
+ inode = find_next_inode(root, key.objectid);
+ if (inode)
+ ivec->inode[ivec->nr++] = inode;
+ }
+ if (inode && inode->i_ino == key.objectid) {
+ end = key.offset +
+ btrfs_file_extent_num_bytes(leaf, fi);
+ WARN_ON(!IS_ALIGNED(key.offset,
+ root->sectorsize));
+ WARN_ON(!IS_ALIGNED(end, root->sectorsize));
+ end--;
+ ret = try_lock_extent(&BTRFS_I(inode)->io_tree,
+ key.offset, end,
+ GFP_NOFS);
+ if (!ret)
+ continue;
+
+ btrfs_drop_extent_cache(inode, key.offset, end,
+ 1);
+ unlock_extent(&BTRFS_I(inode)->io_tree,
+ key.offset, end, GFP_NOFS);
+ }
+ }
+
+ ret = get_new_location(rc->data_inode, &new_bytenr,
+ bytenr, num_bytes);
+ if (ret > 0)
+ continue;
+ BUG_ON(ret < 0);
+
+ btrfs_set_file_extent_disk_bytenr(leaf, fi, new_bytenr);
+ dirty = 1;
+
+ key.offset -= btrfs_file_extent_offset(leaf, fi);
+ ret = btrfs_inc_extent_ref(trans, root, new_bytenr,
+ num_bytes, parent,
+ btrfs_header_owner(leaf),
+ key.objectid, key.offset);
+ BUG_ON(ret);
+
+ ret = btrfs_free_extent(trans, root, bytenr, num_bytes,
+ parent, btrfs_header_owner(leaf),
+ key.objectid, key.offset);
+ BUG_ON(ret);
+ }
+ if (dirty)
+ btrfs_mark_buffer_dirty(leaf);
+ return 0;
+}
+
+static noinline_for_stack
+int memcmp_node_keys(struct extent_buffer *eb, int slot,
+ struct btrfs_path *path, int level)
+{
+ struct btrfs_disk_key key1;
+ struct btrfs_disk_key key2;
+ btrfs_node_key(eb, &key1, slot);
+ btrfs_node_key(path->nodes[level], &key2, path->slots[level]);
+ return memcmp(&key1, &key2, sizeof(key1));
+}
+
+/*
+ * try to replace tree blocks in fs tree with the new blocks
+ * in reloc tree. tree blocks haven't been modified since the
+ * reloc tree was create can be replaced.
+ *
+ * if a block was replaced, level of the block + 1 is returned.
+ * if no block got replaced, 0 is returned. if there are other
+ * errors, a negative error number is returned.
+ */
+static int replace_path(struct btrfs_trans_handle *trans,
+ struct btrfs_root *dest, struct btrfs_root *src,
+ struct btrfs_path *path, struct btrfs_key *next_key,
+ struct extent_buffer **leaf,
+ int lowest_level, int max_level)
+{
+ struct extent_buffer *eb;
+ struct extent_buffer *parent;
+ struct btrfs_key key;
+ u64 old_bytenr;
+ u64 new_bytenr;
+ u64 old_ptr_gen;
+ u64 new_ptr_gen;
+ u64 last_snapshot;
+ u32 blocksize;
+ int level;
+ int ret;
+ int slot;
+
+ BUG_ON(src->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
+ BUG_ON(dest->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID);
+ BUG_ON(lowest_level > 1 && leaf);
+
+ last_snapshot = btrfs_root_last_snapshot(&src->root_item);
+
+ slot = path->slots[lowest_level];
+ btrfs_node_key_to_cpu(path->nodes[lowest_level], &key, slot);
+
+ eb = btrfs_lock_root_node(dest);
+ btrfs_set_lock_blocking(eb);
+ level = btrfs_header_level(eb);
+
+ if (level < lowest_level) {
+ btrfs_tree_unlock(eb);
+ free_extent_buffer(eb);
+ return 0;
+ }
+
+ ret = btrfs_cow_block(trans, dest, eb, NULL, 0, &eb);
+ BUG_ON(ret);
+ btrfs_set_lock_blocking(eb);
+
+ if (next_key) {
+ next_key->objectid = (u64)-1;
+ next_key->type = (u8)-1;
+ next_key->offset = (u64)-1;
+ }
+
+ parent = eb;
+ while (1) {
+ level = btrfs_header_level(parent);
+ BUG_ON(level < lowest_level);
+
+ ret = btrfs_bin_search(parent, &key, level, &slot);
+ if (ret && slot > 0)
+ slot--;
+
+ if (next_key && slot + 1 < btrfs_header_nritems(parent))
+ btrfs_node_key_to_cpu(parent, next_key, slot + 1);
+
+ old_bytenr = btrfs_node_blockptr(parent, slot);
+ blocksize = btrfs_level_size(dest, level - 1);
+ old_ptr_gen = btrfs_node_ptr_generation(parent, slot);
+
+ if (level <= max_level) {
+ eb = path->nodes[level];
+ new_bytenr = btrfs_node_blockptr(eb,
+ path->slots[level]);
+ new_ptr_gen = btrfs_node_ptr_generation(eb,
+ path->slots[level]);
+ } else {
+ new_bytenr = 0;
+ new_ptr_gen = 0;
+ }
+
+ if (new_bytenr > 0 && new_bytenr == old_bytenr) {
+ WARN_ON(1);
+ ret = level;
+ break;
+ }
+
+ if (new_bytenr == 0 || old_ptr_gen > last_snapshot ||
+ memcmp_node_keys(parent, slot, path, level)) {
+ if (level <= lowest_level && !leaf) {
+ ret = 0;
+ break;
+ }
+
+ eb = read_tree_block(dest, old_bytenr, blocksize,
+ old_ptr_gen);
+ btrfs_tree_lock(eb);
+ ret = btrfs_cow_block(trans, dest, eb, parent,
+ slot, &eb);
+ BUG_ON(ret);
+ btrfs_set_lock_blocking(eb);
+
+ if (level <= lowest_level) {
+ *leaf = eb;
+ ret = 0;
+ break;
+ }
+
+ btrfs_tree_unlock(parent);
+ free_extent_buffer(parent);
+
+ parent = eb;
+ continue;
+ }
+
+ btrfs_node_key_to_cpu(path->nodes[level], &key,
+ path->slots[level]);
+ btrfs_release_path(src, path);
+
+ path->lowest_level = level;
+ ret = btrfs_search_slot(trans, src, &key, path, 0, 1);
+ path->lowest_level = 0;
+ BUG_ON(ret);
+
+ /*
+ * swap blocks in fs tree and reloc tree.
+ */
+ btrfs_set_node_blockptr(parent, slot, new_bytenr);
+ btrfs_set_node_ptr_generation(parent, slot, new_ptr_gen);
+ btrfs_mark_buffer_dirty(parent);
+
+ btrfs_set_node_blockptr(path->nodes[level],
+ path->slots[level], old_bytenr);
+ btrfs_set_node_ptr_generation(path->nodes[level],
+ path->slots[level], old_ptr_gen);
+ btrfs_mark_buffer_dirty(path->nodes[level]);
+
+ ret = btrfs_inc_extent_ref(trans, src, old_bytenr, blocksize,
+ path->nodes[level]->start,
+ src->root_key.objectid, level - 1, 0);
+ BUG_ON(ret);
+ ret = btrfs_inc_extent_ref(trans, dest, new_bytenr, blocksize,
+ 0, dest->root_key.objectid, level - 1,
+ 0);
+ BUG_ON(ret);
+
+ ret = btrfs_free_extent(trans, src, new_bytenr, blocksize,
+ path->nodes[level]->start,
+ src->root_key.objectid, level - 1, 0);
+ BUG_ON(ret);
+
+ ret = btrfs_free_extent(trans, dest, old_bytenr, blocksize,
+ 0, dest->root_key.objectid, level - 1,
+ 0);
+ BUG_ON(ret);
+
+ btrfs_unlock_up_safe(path, 0);
+
+ ret = level;
+ break;
+ }
+ btrfs_tree_unlock(parent);
+ free_extent_buffer(parent);
+ return ret;
+}
+
+/*
+ * helper to find next relocated block in reloc tree
+ */
+static noinline_for_stack
+int walk_up_reloc_tree(struct btrfs_root *root, struct btrfs_path *path,
+ int *level)
+{
+ struct extent_buffer *eb;
+ int i;
+ u64 last_snapshot;
+ u32 nritems;
+
+ last_snapshot = btrfs_root_last_snapshot(&root->root_item);
+
+ for (i = 0; i < *level; i++) {
+ free_extent_buffer(path->nodes[i]);
+ path->nodes[i] = NULL;
+ }
+
+ for (i = *level; i < BTRFS_MAX_LEVEL && path->nodes[i]; i++) {
+ eb = path->nodes[i];
+ nritems = btrfs_header_nritems(eb);
+ while (path->slots[i] + 1 < nritems) {
+ path->slots[i]++;
+ if (btrfs_node_ptr_generation(eb, path->slots[i]) <=
+ last_snapshot)
+ continue;
+
+ *level = i;
+ return 0;
+ }
+ free_extent_buffer(path->nodes[i]);
+ path->nodes[i] = NULL;
+ }
+ return 1;
+}
+
+/*
+ * walk down reloc tree to find relocated block of lowest level
+ */
+static noinline_for_stack
+int walk_down_reloc_tree(struct btrfs_root *root, struct btrfs_path *path,
+ int *level)
+{
+ struct extent_buffer *eb = NULL;
+ int i;
+ u64 bytenr;
+ u64 ptr_gen = 0;
+ u64 last_snapshot;
+ u32 blocksize;
+ u32 nritems;
+
+ last_snapshot = btrfs_root_last_snapshot(&root->root_item);
+
+ for (i = *level; i > 0; i--) {
+ eb = path->nodes[i];
+ nritems = btrfs_header_nritems(eb);
+ while (path->slots[i] < nritems) {
+ ptr_gen = btrfs_node_ptr_generation(eb, path->slots[i]);
+ if (ptr_gen > last_snapshot)
+ break;
+ path->slots[i]++;
+ }
+ if (path->slots[i] >= nritems) {
+ if (i == *level)
+ break;
+ *level = i + 1;
+ return 0;
+ }
+ if (i == 1) {
+ *level = i;
+ return 0;
+ }
+
+ bytenr = btrfs_node_blockptr(eb, path->slots[i]);
+ blocksize = btrfs_level_size(root, i - 1);
+ eb = read_tree_block(root, bytenr, blocksize, ptr_gen);
+ BUG_ON(btrfs_header_level(eb) != i - 1);
+ path->nodes[i - 1] = eb;
+ path->slots[i - 1] = 0;
+ }
+ return 1;
+}
+
+/*
+ * invalidate extent cache for file extents whose key in range of
+ * [min_key, max_key)
+ */
+static int invalidate_extent_cache(struct btrfs_root *root,
+ struct btrfs_key *min_key,
+ struct btrfs_key *max_key)
+{
+ struct inode *inode = NULL;
+ u64 objectid;
+ u64 start, end;
+
+ objectid = min_key->objectid;
+ while (1) {
+ cond_resched();
+ iput(inode);
+
+ if (objectid > max_key->objectid)
+ break;
+
+ inode = find_next_inode(root, objectid);
+ if (!inode)
+ break;
+
+ if (inode->i_ino > max_key->objectid) {
+ iput(inode);
+ break;
+ }
+
+ objectid = inode->i_ino + 1;
+ if (!S_ISREG(inode->i_mode))
+ continue;
+
+ if (unlikely(min_key->objectid == inode->i_ino)) {
+ if (min_key->type > BTRFS_EXTENT_DATA_KEY)
+ continue;
+ if (min_key->type < BTRFS_EXTENT_DATA_KEY)
+ start = 0;
+ else {
+ start = min_key->offset;
+ WARN_ON(!IS_ALIGNED(start, root->sectorsize));
+ }
+ } else {
+ start = 0;
+ }
+
+ if (unlikely(max_key->objectid == inode->i_ino)) {
+ if (max_key->type < BTRFS_EXTENT_DATA_KEY)
+ continue;
+ if (max_key->type > BTRFS_EXTENT_DATA_KEY) {
+ end = (u64)-1;
+ } else {
+ if (max_key->offset == 0)
+ continue;
+ end = max_key->offset;
+ WARN_ON(!IS_ALIGNED(end, root->sectorsize));
+ end--;
+ }
+ } else {
+ end = (u64)-1;
+ }
+
+ /* the lock_extent waits for readpage to complete */
+ lock_extent(&BTRFS_I(inode)->io_tree, start, end, GFP_NOFS);
+ btrfs_drop_extent_cache(inode, start, end, 1);
+ unlock_extent(&BTRFS_I(inode)->io_tree, start, end, GFP_NOFS);
+ }
+ return 0;
+}
+
+static int find_next_key(struct btrfs_path *path, int level,
+ struct btrfs_key *key)
+
+{
+ while (level < BTRFS_MAX_LEVEL) {
+ if (!path->nodes[level])
+ break;
+ if (path->slots[level] + 1 <
+ btrfs_header_nritems(path->nodes[level])) {
+ btrfs_node_key_to_cpu(path->nodes[level], key,
+ path->slots[level] + 1);
+ return 0;
+ }
+ level++;
+ }
+ return 1;
+}
+
+/*
+ * merge the relocated tree blocks in reloc tree with corresponding
+ * fs tree.
+ */
+static noinline_for_stack int merge_reloc_root(struct reloc_control *rc,
+ struct btrfs_root *root)
+{
+ LIST_HEAD(inode_list);
+ struct btrfs_key key;
+ struct btrfs_key next_key;
+ struct btrfs_trans_handle *trans;
+ struct btrfs_root *reloc_root;
+ struct btrfs_root_item *root_item;
+ struct btrfs_path *path;
+ struct extent_buffer *leaf = NULL;
+ unsigned long nr;
+ int level;
+ int max_level;
+ int replaced = 0;
+ int ret;
+ int err = 0;
+
+ path = btrfs_alloc_path();
+ if (!path)
+ return -ENOMEM;
+
+ reloc_root = root->reloc_root;
+ root_item = &reloc_root->root_item;
+
+ if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
+ level = btrfs_root_level(root_item);
+ extent_buffer_get(reloc_root->node);
+ path->nodes[level] = reloc_root->node;
+ path->slots[level] = 0;
+ } else {
+ btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
+
+ level = root_item->drop_level;
+ BUG_ON(level == 0);
+ path->lowest_level = level;
+ ret = btrfs_search_slot(NULL, reloc_root, &key, path, 0, 0);
+ if (ret < 0) {
+ btrfs_free_path(path);
+ return ret;
+ }
+
+ btrfs_node_key_to_cpu(path->nodes[level], &next_key,
+ path->slots[level]);
+ WARN_ON(memcmp(&key, &next_key, sizeof(key)));
+
+ btrfs_unlock_up_safe(path, 0);
+ }
+
+ if (level == 0 && rc->stage == UPDATE_DATA_PTRS) {
+ trans = btrfs_start_transaction(root, 1);
+
+ leaf = path->nodes[0];
+ btrfs_item_key_to_cpu(leaf, &key, 0);
+ btrfs_release_path(reloc_root, path);
+
+ ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
+ if (ret < 0) {
+ err = ret;
+ goto out;
+ }
+
+ leaf = path->nodes[0];
+ btrfs_unlock_up_safe(path, 1);
+ ret = replace_file_extents(trans, rc, root, leaf,
+ &inode_list);
+ if (ret < 0)
+ err = ret;
+ goto out;
+ }
+
+ memset(&next_key, 0, sizeof(next_key));
+
+ while (1) {
+ leaf = NULL;
+ replaced = 0;
+ trans = btrfs_start_transaction(root, 1);
+ max_level = level;
+
+ ret = walk_down_reloc_tree(reloc_root, path, &level);
+ if (ret < 0) {
+ err = ret;
+ goto out;
+ }
+ if (ret > 0)
+ break;
+
+ if (!find_next_key(path, level, &key) &&
+ btrfs_comp_cpu_keys(&next_key, &key) >= 0) {
+ ret = 0;
+ } else if (level == 1 && rc->stage == UPDATE_DATA_PTRS) {
+ ret = replace_path(trans, root, reloc_root,
+ path, &next_key, &leaf,
+ level, max_level);
+ } else {
+ ret = replace_path(trans, root, reloc_root,
+ path, &next_key, NULL,
+ level, max_level);
+ }
+ if (ret < 0) {
+ err = ret;
+ goto out;
+ }
+
+ if (ret > 0) {
+ level = ret;
+ btrfs_node_key_to_cpu(path->nodes[level], &key,
+ path->slots[level]);
+ replaced = 1;
+ } else if (leaf) {
+ /*
+ * no block got replaced, try replacing file extents
+ */
+ btrfs_item_key_to_cpu(leaf, &key, 0);
+ ret = replace_file_extents(trans, rc, root, leaf,
+ &inode_list);
+ btrfs_tree_unlock(leaf);
+ free_extent_buffer(leaf);
+ BUG_ON(ret < 0);
+ }
+
+ ret = walk_up_reloc_tree(reloc_root, path, &level);
+ if (ret > 0)
+ break;
+
+ BUG_ON(level == 0);
+ /*
+ * save the merging progress in the drop_progress.
+ * this is OK since root refs == 1 in this case.
+ */
+ btrfs_node_key(path->nodes[level], &root_item->drop_progress,
+ path->slots[level]);
+ root_item->drop_level = level;
+
+ nr = trans->blocks_used;
+ btrfs_end_transaction(trans, root);
+
+ btrfs_btree_balance_dirty(root, nr);
+
+ if (replaced && rc->stage == UPDATE_DATA_PTRS)
+ invalidate_extent_cache(root, &key, &next_key);
+ }
+
+ /*
+ * handle the case only one block in the fs tree need to be
+ * relocated and the block is tree root.
+ */
+ leaf = btrfs_lock_root_node(root);
+ ret = btrfs_cow_block(trans, root, leaf, NULL, 0, &leaf);
+ btrfs_tree_unlock(leaf);
+ free_extent_buffer(leaf);
+ if (ret < 0)
+ err = ret;
+out:
+ btrfs_free_path(path);
+
+ if (err == 0) {
+ memset(&root_item->drop_progress, 0,
+ sizeof(root_item->drop_progress));
+ root_item->drop_level = 0;
+ btrfs_set_root_refs(root_item, 0);
+ }
+
+ nr = trans->blocks_used;
+ btrfs_end_transaction(trans, root);
+
+ btrfs_btree_balance_dirty(root, nr);
+
+ /*
+ * put inodes while we aren't holding the tree locks
+ */
+ while (!list_empty(&inode_list)) {
+ struct inodevec *ivec;
+ ivec = list_entry(inode_list.next, struct inodevec, list);
+ list_del(&ivec->list);
+ while (ivec->nr > 0) {
+ ivec->nr--;
+ iput(ivec->inode[ivec->nr]);
+ }
+ kfree(ivec);
+ }
+
+ if (replaced && rc->stage == UPDATE_DATA_PTRS)
+ invalidate_extent_cache(root, &key, &next_key);
+
+ return err;
+}
+
+/*
+ * callback for the work threads.
+ * this function merges reloc tree with corresponding fs tree,
+ * and then drops the reloc tree.
+ */
+static void merge_func(struct btrfs_work *work)
+{
+ struct btrfs_trans_handle *trans;
+ struct btrfs_root *root;
+ struct btrfs_root *reloc_root;
+ struct async_merge *async;
+
+ async = container_of(work, struct async_merge, work);
+ reloc_root = async->root;
+
+ if (btrfs_root_refs(&reloc_root->root_item) > 0) {
+ root = read_fs_root(reloc_root->fs_info,
+ reloc_root->root_key.offset);
+ BUG_ON(IS_ERR(root));
+ BUG_ON(root->reloc_root != reloc_root);
+
+ merge_reloc_root(async->rc, root);
+
+ trans = btrfs_start_transaction(root, 1);
+ btrfs_update_reloc_root(trans, root);
+ btrfs_end_transaction(trans, root);
+ }
+
+ btrfs_drop_dead_root(reloc_root);
+
+ if (atomic_dec_and_test(async->num_pending))
+ complete(async->done);
+
+ kfree(async);
+}
+
+static int merge_reloc_roots(struct reloc_control *rc)
+{
+ struct async_merge *async;
+ struct btrfs_root *root;
+ struct completion done;
+ atomic_t num_pending;
+
+ init_completion(&done);
+ atomic_set(&num_pending, 1);
+
+ while (!list_empty(&rc->reloc_roots)) {
+ root = list_entry(rc->reloc_roots.next,
+ struct btrfs_root, root_list);
+ list_del_init(&root->root_list);
+
+ async = kmalloc(sizeof(*async), GFP_NOFS);
+ BUG_ON(!async);
+ async->work.func = merge_func;
+ async->work.flags = 0;
+ async->rc = rc;
+ async->root = root;
+ async->done = &done;
+ async->num_pending = &num_pending;
+ atomic_inc(&num_pending);
+ btrfs_queue_worker(&rc->workers, &async->work);
+ }
+
+ if (!atomic_dec_and_test(&num_pending))
+ wait_for_completion(&done);
+
+ BUG_ON(!RB_EMPTY_ROOT(&rc->reloc_root_tree.rb_root));
+ return 0;
+}
+
+static void free_block_list(struct rb_root *blocks)
+{
+ struct tree_block *block;
+ struct rb_node *rb_node;
+ while ((rb_node = rb_first(blocks))) {
+ block = rb_entry(rb_node, struct tree_block, rb_node);
+ rb_erase(rb_node, blocks);
+ kfree(block);
+ }
+}
+
+static int record_reloc_root_in_trans(struct btrfs_trans_handle *trans,
+ struct btrfs_root *reloc_root)
+{
+ struct btrfs_root *root;
+
+ if (reloc_root->last_trans == trans->transid)
+ return 0;
+
+ root = read_fs_root(reloc_root->fs_info, reloc_root->root_key.offset);
+ BUG_ON(IS_ERR(root));
+ BUG_ON(root->reloc_root != reloc_root);
+
+ return btrfs_record_root_in_trans(trans, root);
+}
+
+/*
+ * select one tree from trees that references the block.
+ * for blocks in refernce counted trees, we preper reloc tree.
+ * if no reloc tree found and reloc_only is true, NULL is returned.
+ */
+static struct btrfs_root *__select_one_root(struct btrfs_trans_handle *trans,
+ struct backref_node *node,
+ struct backref_edge *edges[],
+ int *nr, int reloc_only)
+{
+ struct backref_node *next;
+ struct btrfs_root *root;
+ int index;
+ int loop = 0;
+again:
+ index = 0;
+ next = node;
+ while (1) {
+ cond_resched();
+ next = walk_up_backref(next, edges, &index);
+ root = next->root;
+ if (!root) {
+ BUG_ON(!node->old_root);
+ goto skip;
+ }
+
+ /* no other choice for non-refernce counted tree */
+ if (!root->ref_cows) {
+ BUG_ON(reloc_only);
+ break;
+ }
+
+ if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) {
+ record_reloc_root_in_trans(trans, root);
+ break;
+ }
+
+ if (loop) {
+ btrfs_record_root_in_trans(trans, root);
+ break;
+ }
+
+ if (reloc_only || next != node) {
+ if (!root->reloc_root)
+ btrfs_record_root_in_trans(trans, root);
+ root = root->reloc_root;
+ /*
+ * if the reloc tree was created in current
+ * transation, there is no node in backref tree
+ * corresponds to the root of the reloc tree.
+ */
+ if (btrfs_root_last_snapshot(&root->root_item) ==
+ trans->transid - 1)
+ break;
+ }
+skip:
+ root = NULL;
+ next = walk_down_backref(edges, &index);
+ if (!next || next->level <= node->level)
+ break;
+ }
+
+ if (!root && !loop && !reloc_only) {
+ loop = 1;
+ goto again;
+ }
+
+ if (root)
+ *nr = index;
+ else
+ *nr = 0;
+
+ return root;
+}
+
+static noinline_for_stack
+struct btrfs_root *select_one_root(struct btrfs_trans_handle *trans,
+ struct backref_node *node)
+{
+ struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
+ int nr;
+ return __select_one_root(trans, node, edges, &nr, 0);
+}
+
+static noinline_for_stack
+struct btrfs_root *select_reloc_root(struct btrfs_trans_handle *trans,
+ struct backref_node *node,
+ struct backref_edge *edges[], int *nr)
+{
+ return __select_one_root(trans, node, edges, nr, 1);
+}
+
+static void grab_path_buffers(struct btrfs_path *path,
+ struct backref_node *node,
+ struct backref_edge *edges[], int nr)
+{
+ int i = 0;
+ while (1) {
+ drop_node_buffer(node);
+ node->eb = path->nodes[node->level];
+ BUG_ON(!node->eb);
+ if (path->locks[node->level])
+ node->locked = 1;
+ path->nodes[node->level] = NULL;
+ path->locks[node->level] = 0;
+
+ if (i >= nr)
+ break;
+
+ edges[i]->blockptr = node->eb->start;
+ node = edges[i]->node[UPPER];
+ i++;
+ }
+}
+
+/*
+ * relocate a block tree, and then update pointers in upper level
+ * blocks that reference the block to point to the new location.
+ *
+ * if called by link_to_upper, the block has already been relocated.
+ * in that case this function just updates pointers.
+ */
+static int do_relocation(struct btrfs_trans_handle *trans,
+ struct backref_node *node,
+ struct btrfs_key *key,
+ struct btrfs_path *path, int lowest)
+{
+ struct backref_node *upper;
+ struct backref_edge *edge;
+ struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
+ struct btrfs_root *root;
+ struct extent_buffer *eb;
+ u32 blocksize;
+ u64 bytenr;
+ u64 generation;
+ int nr;
+ int slot;
+ int ret;
+ int err = 0;
+
+ BUG_ON(lowest && node->eb);
+
+ path->lowest_level = node->level + 1;
+ list_for_each_entry(edge, &node->upper, list[LOWER]) {
+ cond_resched();
+ if (node->eb && node->eb->start == edge->blockptr)
+ continue;
+
+ upper = edge->node[UPPER];
+ root = select_reloc_root(trans, upper, edges, &nr);
+ if (!root)
+ continue;
+
+ if (upper->eb && !upper->locked)
+ drop_node_buffer(upper);
+
+ if (!upper->eb) {
+ ret = btrfs_search_slot(trans, root, key, path, 0, 1);
+ if (ret < 0) {
+ err = ret;
+ break;
+ }
+ BUG_ON(ret > 0);
+
+ slot = path->slots[upper->level];
+
+ btrfs_unlock_up_safe(path, upper->level + 1);
+ grab_path_buffers(path, upper, edges, nr);
+
+ btrfs_release_path(NULL, path);
+ } else {
+ ret = btrfs_bin_search(upper->eb, key, upper->level,
+ &slot);
+ BUG_ON(ret);
+ }
+
+ bytenr = btrfs_node_blockptr(upper->eb, slot);
+ if (!lowest) {
+ if (node->eb->start == bytenr) {
+ btrfs_tree_unlock(upper->eb);
+ upper->locked = 0;
+ continue;
+ }
+ } else {
+ BUG_ON(node->bytenr != bytenr);
+ }
+
+ blocksize = btrfs_level_size(root, node->level);
+ generation = btrfs_node_ptr_generation(upper->eb, slot);
+ eb = read_tree_block(root, bytenr, blocksize, generation);
+ btrfs_tree_lock(eb);
+ btrfs_set_lock_blocking(eb);
+
+ if (!node->eb) {
+ ret = btrfs_cow_block(trans, root, eb, upper->eb,
+ slot, &eb);
+ if (ret < 0) {
+ err = ret;
+ break;
+ }
+ btrfs_set_lock_blocking(eb);
+ node->eb = eb;
+ node->locked = 1;
+ } else {
+ btrfs_set_node_blockptr(upper->eb, slot,
+ node->eb->start);
+ btrfs_set_node_ptr_generation(upper->eb, slot,
+ trans->transid);
+ btrfs_mark_buffer_dirty(upper->eb);
+
+ ret = btrfs_inc_extent_ref(trans, root,
+ node->eb->start, blocksize,
+ upper->eb->start,
+ btrfs_header_owner(upper->eb),
+ node->level, 0);
+ BUG_ON(ret);
+
+ ret = btrfs_drop_subtree(trans, root, eb, upper->eb);
+ BUG_ON(ret);
+
+ btrfs_tree_unlock(eb);
+ free_extent_buffer(eb);
+ }
+ if (!lowest) {
+ btrfs_tree_unlock(upper->eb);
+ upper->locked = 0;
+ }
+ }
+ path->lowest_level = 0;
+ return err;
+}
+
+static int link_to_upper(struct btrfs_trans_handle *trans,
+ struct backref_node *node,
+ struct btrfs_path *path)
+{
+ struct btrfs_key key;
+ if (!node->eb || list_empty(&node->upper))
+ return 0;
+
+ btrfs_node_key_to_cpu(node->eb, &key, 0);
+ return do_relocation(trans, node, &key, path, 0);
+}
+
+static int finish_pending_nodes(struct btrfs_trans_handle *trans,
+ struct backref_cache *cache,
+ struct btrfs_path *path)
+{
+ struct backref_node *node;
+ int level;
+ int ret;
+ int err = 0;
+
+ for (level = 0; level < BTRFS_MAX_LEVEL; level++) {
+ while (!list_empty(&cache->pending[level])) {
+ node = list_entry(cache->pending[level].next,
+ struct backref_node, lower);
+ BUG_ON(node->level != level);
+
+ ret = link_to_upper(trans, node, path);
+ if (ret < 0)
+ err = ret;
+ /*
+ * this remove the node from the pending list and
+ * may add some other nodes to the level + 1
+ * pending list
+ */
+ remove_backref_node(cache, node);
+ }
+ }
+ BUG_ON(!RB_EMPTY_ROOT(&cache->rb_root));
+ return err;
+}
+
+static void mark_block_processed(struct reloc_control *rc,
+ struct backref_node *node)
+{
+ u32 blocksize;
+ if (node->level == 0 ||
+ in_block_group(node->bytenr, rc->block_group)) {
+ blocksize = btrfs_level_size(rc->extent_root, node->level);
+ set_extent_bits(&rc->processed_blocks, node->bytenr,
+ node->bytenr + blocksize - 1, EXTENT_DIRTY,
+ GFP_NOFS);
+ }
+ node->processed = 1;
+}
+
+/*
+ * mark a block and all blocks directly/indirectly reference the block
+ * as processed.
+ */
+static void update_processed_blocks(struct reloc_control *rc,
+ struct backref_node *node)
+{
+ struct backref_node *next = node;
+ struct backref_edge *edge;
+ struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
+ int index = 0;
+
+ while (next) {
+ cond_resched();
+ while (1) {
+ if (next->processed)
+ break;
+
+ mark_block_processed(rc, next);
+
+ if (list_empty(&next->upper))
+ break;
+
+ edge = list_entry(next->upper.next,
+ struct backref_edge, list[LOWER]);
+ edges[index++] = edge;
+ next = edge->node[UPPER];
+ }
+ next = walk_down_backref(edges, &index);
+ }
+}
+
+static int tree_block_processed(u64 bytenr, u32 blocksize,
+ struct reloc_control *rc)
+{
+ if (test_range_bit(&rc->processed_blocks, bytenr,
+ bytenr + blocksize - 1, EXTENT_DIRTY, 1))
+ return 1;
+ return 0;
+}
+
+/*
+ * check if there are any file extent pointers in the leaf point to
+ * data require processing
+ */
+static int check_file_extents(struct reloc_control *rc,
+ u64 bytenr, u32 blocksize, u64 ptr_gen)
+{
+ struct btrfs_key found_key;
+ struct btrfs_file_extent_item *fi;
+ struct extent_buffer *leaf;
+ u32 nritems;
+ int i;
+ int ret = 0;
+
+ leaf = read_tree_block(rc->extent_root, bytenr, blocksize, ptr_gen);
+
+ nritems = btrfs_header_nritems(leaf);
+ for (i = 0; i < nritems; i++) {
+ cond_resched();
+ btrfs_item_key_to_cpu(leaf, &found_key, i);
+ if (found_key.type != BTRFS_EXTENT_DATA_KEY)
+ continue;
+ fi = btrfs_item_ptr(leaf, i, struct btrfs_file_extent_item);
+ if (btrfs_file_extent_type(leaf, fi) ==
+ BTRFS_FILE_EXTENT_INLINE)
+ continue;
+ bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
+ if (bytenr == 0)
+ continue;
+ if (in_block_group(bytenr, rc->block_group)) {
+ ret = 1;
+ break;
+ }
+ }
+ free_extent_buffer(leaf);
+ return ret;
+}
+
+/*
+ * scan child blocks of a given block to find blocks require processing
+ */
+static int add_child_blocks(struct btrfs_trans_handle *trans,
+ struct reloc_control *rc,
+ struct backref_node *node,
+ struct rb_root *blocks)
+{
+ struct tree_block *block;
+ struct rb_node *rb_node;
+ u64 bytenr;
+ u64 ptr_gen;
+ u32 blocksize;
+ u32 nritems;
+ int i;
+ int err = 0;
+
+ nritems = btrfs_header_nritems(node->eb);
+ blocksize = btrfs_level_size(rc->extent_root, node->level - 1);
+ for (i = 0; i < nritems; i++) {
+ cond_resched();
+ bytenr = btrfs_node_blockptr(node->eb, i);
+ ptr_gen = btrfs_node_ptr_generation(node->eb, i);
+ if (ptr_gen == trans->transid)
+ continue;
+ if (!in_block_group(bytenr, rc->block_group) &&
+ (node->level > 1 || rc->stage == MOVE_DATA_EXTENTS))
+ continue;
+ if (tree_block_processed(bytenr, blocksize, rc))
+ continue;
+
+ readahead_tree_block(rc->extent_root,
+ bytenr, blocksize, ptr_gen);
+ }
+
+ for (i = 0; i < nritems; i++) {
+ cond_resched();
+ bytenr = btrfs_node_blockptr(node->eb, i);
+ ptr_gen = btrfs_node_ptr_generation(node->eb, i);
+ if (ptr_gen == trans->transid)
+ continue;
+ if (!in_block_group(bytenr, rc->block_group) &&
+ (node->level > 1 || rc->stage == MOVE_DATA_EXTENTS))
+ continue;
+ if (tree_block_processed(bytenr, blocksize, rc))
+ continue;
+ if (!in_block_group(bytenr, rc->block_group) &&
+ !check_file_extents(rc, bytenr, blocksize, ptr_gen))
+ continue;
+
+ block = kmalloc(sizeof(*block), GFP_NOFS);
+ if (!block) {
+ err = -ENOMEM;
+ break;
+ }
+ block->bytenr = bytenr;
+ btrfs_node_key_to_cpu(node->eb, &block->key, i);
+ block->level = node->level - 1;
+ block->key_ready = 1;
+ rb_node = tree_insert(blocks, block->bytenr, &block->rb_node);
+ BUG_ON(rb_node);
+ }
+ if (err)
+ free_block_list(blocks);
+ return err;
+}
+
+/*
+ * find adjacent blocks require processing
+ */
+static noinline_for_stack
+int add_adjacent_blocks(struct btrfs_trans_handle *trans,
+ struct reloc_control *rc,
+ struct backref_cache *cache,
+ struct rb_root *blocks, int level,
+ struct backref_node **upper)
+{
+ struct backref_node *node;
+ int ret = 0;
+
+ WARN_ON(!list_empty(&cache->pending[level]));
+
+ if (list_empty(&cache->pending[level + 1]))
+ return 1;
+
+ node = list_entry(cache->pending[level + 1].next,
+ struct backref_node, lower);
+ if (node->eb)
+ ret = add_child_blocks(trans, rc, node, blocks);
+
+ *upper = node;
+ return ret;
+}
+
+static int get_tree_block_key(struct reloc_control *rc,
+ struct tree_block *block)
+{
+ struct extent_buffer *eb;
+
+ BUG_ON(block->key_ready);
+ eb = read_tree_block(rc->extent_root, block->bytenr,
+ block->key.objectid, block->key.offset);
+ WARN_ON(btrfs_header_level(eb) != block->level);
+ if (block->level == 0)
+ btrfs_item_key_to_cpu(eb, &block->key, 0);
+ else
+ btrfs_node_key_to_cpu(eb, &block->key, 0);
+ free_extent_buffer(eb);
+ block->key_ready = 1;
+ return 0;
+}
+
+static int reada_tree_block(struct reloc_control *rc,
+ struct tree_block *block)
+{
+ BUG_ON(block->key_ready);
+ readahead_tree_block(rc->extent_root, block->bytenr,
+ block->key.objectid, block->key.offset);
+ return 0;
+}
+
+/*
+ * helper function to relocate a tree block
+ */
+static int relocate_tree_block(struct btrfs_trans_handle *trans,
+ struct reloc_control *rc,
+ struct backref_node *node,
+ struct btrfs_key *key,
+ struct btrfs_path *path)
+{
+ struct btrfs_root *root;
+ int ret;
+
+ root = select_one_root(trans, node);
+ if (unlikely(!root)) {
+ rc->found_old_snapshot = 1;
+ update_processed_blocks(rc, node);
+ return 0;
+ }
+
+ if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) {
+ ret = do_relocation(trans, node, key, path, 1);
+ if (ret < 0)
+ goto out;
+ if (node->level == 0 && rc->stage == UPDATE_DATA_PTRS) {
+ ret = replace_file_extents(trans, rc, root,
+ node->eb, NULL);
+ if (ret < 0)
+ goto out;
+ }
+ drop_node_buffer(node);
+ } else if (!root->ref_cows) {
+ path->lowest_level = node->level;
+ ret = btrfs_search_slot(trans, root, key, path, 0, 1);
+ btrfs_release_path(root, path);
+ if (ret < 0)
+ goto out;
+ } else if (root != node->root) {
+ WARN_ON(node->level > 0 || rc->stage != UPDATE_DATA_PTRS);
+ }
+
+ update_processed_blocks(rc, node);
+ ret = 0;
+out:
+ drop_node_buffer(node);
+ return ret;
+}
+
+/*
+ * relocate a list of blocks
+ */
+static noinline_for_stack
+int relocate_tree_blocks(struct btrfs_trans_handle *trans,
+ struct reloc_control *rc, struct rb_root *blocks)
+{
+ struct backref_cache *cache;
+ struct backref_node *node;
+ struct btrfs_path *path;
+ struct tree_block *block;
+ struct rb_node *rb_node;
+ int level = -1;
+ int ret;
+ int err = 0;
+
+ path = btrfs_alloc_path();
+ if (!path)
+ return -ENOMEM;
+
+ cache = kmalloc(sizeof(*cache), GFP_NOFS);
+ if (!cache) {
+ btrfs_free_path(path);
+ return -ENOMEM;
+ }
+
+ backref_cache_init(cache);
+
+ rb_node = rb_first(blocks);
+ while (rb_node) {
+ block = rb_entry(rb_node, struct tree_block, rb_node);
+ if (level == -1)
+ level = block->level;
+ else
+ BUG_ON(level != block->level);
+ if (!block->key_ready)
+ reada_tree_block(rc, block);
+ rb_node = rb_next(rb_node);
+ }
+
+ rb_node = rb_first(blocks);
+ while (rb_node) {
+ block = rb_entry(rb_node, struct tree_block, rb_node);
+ if (!block->key_ready)
+ get_tree_block_key(rc, block);
+ rb_node = rb_next(rb_node);
+ }
+
+ rb_node = rb_first(blocks);
+ while (rb_node) {
+ block = rb_entry(rb_node, struct tree_block, rb_node);
+
+ node = build_backref_tree(rc, cache, &block->key,
+ block->level, block->bytenr);
+ if (IS_ERR(node)) {
+ err = PTR_ERR(node);
+ goto out;
+ }
+
+ ret = relocate_tree_block(trans, rc, node, &block->key,
+ path);
+ if (ret < 0) {
+ err = ret;
+ goto out;
+ }
+ remove_backref_node(cache, node);
+ rb_node = rb_next(rb_node);
+ }
+
+ if (level > 0)
+ goto out;
+
+ free_block_list(blocks);
+
+ /*
+ * now backrefs of some upper level tree blocks have been cached,
+ * try relocating blocks referenced by these upper level blocks.
+ */
+ while (1) {
+ struct backref_node *upper = NULL;
+ if (trans->transaction->in_commit ||
+ trans->transaction->delayed_refs.flushing)
+ break;
+
+ ret = add_adjacent_blocks(trans, rc, cache, blocks, level,
+ &upper);
+ if (ret < 0)
+ err = ret;
+ if (ret != 0)
+ break;
+
+ rb_node = rb_first(blocks);
+ while (rb_node) {
+ block = rb_entry(rb_node, struct tree_block, rb_node);
+ if (trans->transaction->in_commit ||
+ trans->transaction->delayed_refs.flushing)
+ goto out;
+ BUG_ON(!block->key_ready);
+ node = build_backref_tree(rc, cache, &block->key,
+ level, block->bytenr);
+ if (IS_ERR(node)) {
+ err = PTR_ERR(node);
+ goto out;
+ }
+
+ ret = relocate_tree_block(trans, rc, node,
+ &block->key, path);
+ if (ret < 0) {
+ err = ret;
+ goto out;
+ }
+ remove_backref_node(cache, node);
+ rb_node = rb_next(rb_node);
+ }
+ free_block_list(blocks);
+
+ if (upper) {
+ ret = link_to_upper(trans, upper, path);
+ if (ret < 0) {
+ err = ret;
+ break;
+ }
+ remove_backref_node(cache, upper);
+ }
+ }
+out:
+ free_block_list(blocks);
+
+ ret = finish_pending_nodes(trans, cache, path);
+ if (ret < 0)
+ err = ret;
+
+ kfree(cache);
+ btrfs_free_path(path);
+ return err;
+}
+
+static noinline_for_stack
+int relocate_inode_pages(struct inode *inode, u64 start, u64 len)
+{
+ u64 page_start;
+ u64 page_end;
+ unsigned long i;
+ unsigned long first_index;
+ unsigned long last_index;
+ unsigned int total_read = 0;
+ unsigned int total_dirty = 0;
+ struct page *page;
+ struct file_ra_state *ra;
+ struct btrfs_ordered_extent *ordered;
+ struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
+ int ret = 0;
+
+ ra = kzalloc(sizeof(*ra), GFP_NOFS);
+ if (!ra)
+ return -ENOMEM;
+
+ mutex_lock(&inode->i_mutex);
+ first_index = start >> PAGE_CACHE_SHIFT;
+ last_index = (start + len - 1) >> PAGE_CACHE_SHIFT;
+
+ /* make sure the dirty trick played by the caller work */
+ ret = invalidate_inode_pages2_range(inode->i_mapping,
+ first_index, last_index);
+ if (ret)
+ goto out_unlock;
+
+ file_ra_state_init(ra, inode->i_mapping);
+
+ for (i = first_index ; i <= last_index; i++) {
+ if (total_read % ra->ra_pages == 0) {
+ btrfs_force_ra(inode->i_mapping, ra, NULL, i,
+ min(last_index, ra->ra_pages + i - 1));
+ }
+ total_read++;
+again:
+ if (((u64)i << PAGE_CACHE_SHIFT) > i_size_read(inode))
+ BUG_ON(1);
+ page = grab_cache_page(inode->i_mapping, i);
+ if (!page) {
+ ret = -ENOMEM;
+ goto out_unlock;
+ }
+ if (!PageUptodate(page)) {
+ btrfs_readpage(NULL, page);
+ lock_page(page);
+ if (!PageUptodate(page)) {
+ unlock_page(page);
+ page_cache_release(page);
+ ret = -EIO;
+ goto out_unlock;
+ }
+ }
+ wait_on_page_writeback(page);
+
+ page_start = (u64)page->index << PAGE_CACHE_SHIFT;
+ page_end = page_start + PAGE_CACHE_SIZE - 1;
+ lock_extent(io_tree, page_start, page_end, GFP_NOFS);
+
+ ordered = btrfs_lookup_ordered_extent(inode, page_start);
+ if (ordered) {
+ unlock_extent(io_tree, page_start, page_end, GFP_NOFS);
+ unlock_page(page);
+ page_cache_release(page);
+ btrfs_start_ordered_extent(inode, ordered, 1);
+ btrfs_put_ordered_extent(ordered);
+ goto again;
+ }
+ set_page_extent_mapped(page);
+
+ if (i == first_index)
+ set_extent_bits(io_tree, page_start, page_end,
+ EXTENT_BOUNDARY, GFP_NOFS);
+ btrfs_set_extent_delalloc(inode, page_start, page_end);
+
+ set_page_dirty(page);
+ total_dirty++;
+
+ unlock_extent(io_tree, page_start, page_end, GFP_NOFS);
+ unlock_page(page);
+ page_cache_release(page);
+ }
+out_unlock:
+ mutex_unlock(&inode->i_mutex);
+ kfree(ra);
+ balance_dirty_pages_ratelimited_nr(inode->i_mapping, total_dirty);
+ return ret;
+}
+
+static noinline_for_stack
+int relocate_data_extent(struct inode *inode, struct btrfs_key *extent_key)
+{
+ struct btrfs_root *root = BTRFS_I(inode)->root;
+ struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
+ struct extent_map *em;
+ u64 start = extent_key->objectid - BTRFS_I(inode)->index_cnt;
+ u64 end = start + extent_key->offset - 1;
+
+ em = alloc_extent_map(GFP_NOFS);
+ em->start = start;
+ em->len = extent_key->offset;
+ em->block_len = extent_key->offset;
+ em->block_start = extent_key->objectid;
+ em->bdev = root->fs_info->fs_devices->latest_bdev;
+ set_bit(EXTENT_FLAG_PINNED, &em->flags);
+
+ /* setup extent map to cheat btrfs_readpage */
+ lock_extent(&BTRFS_I(inode)->io_tree, start, end, GFP_NOFS);
+ while (1) {
+ int ret;
+ spin_lock(&em_tree->lock);
+ ret = add_extent_mapping(em_tree, em);
+ spin_unlock(&em_tree->lock);
+ if (ret != -EEXIST) {
+ free_extent_map(em);
+ break;
+ }
+ btrfs_drop_extent_cache(inode, start, end, 0);
+ }
+ unlock_extent(&BTRFS_I(inode)->io_tree, start, end, GFP_NOFS);
+
+ return relocate_inode_pages(inode, start, extent_key->offset);
+}
+
+#ifdef BTRFS_COMPAT_EXTENT_TREE_V0
+static int get_ref_objectid_v0(struct reloc_control *rc,
+ struct btrfs_path *path,
+ struct btrfs_key *extent_key,
+ u64 *ref_objectid, int *path_change)
+{
+ struct btrfs_key key;
+ struct extent_buffer *leaf;
+ struct btrfs_extent_ref_v0 *ref0;
+ int ret;
+ int slot;
+
+ leaf = path->nodes[0];
+ slot = path->slots[0];
+ while (1) {
+ if (slot >= btrfs_header_nritems(leaf)) {
+ ret = btrfs_next_leaf(rc->extent_root, path);
+ if (ret < 0)
+ return ret;
+ BUG_ON(ret > 0);
+ leaf = path->nodes[0];
+ slot = path->slots[0];
+ if (path_change)
+ *path_change = 1;
+ }
+ btrfs_item_key_to_cpu(leaf, &key, slot);
+ if (key.objectid != extent_key->objectid)
+ return -ENOENT;
+
+ if (key.type != BTRFS_EXTENT_REF_V0_KEY) {
+ slot++;
+ continue;
+ }
+ ref0 = btrfs_item_ptr(leaf, slot,
+ struct btrfs_extent_ref_v0);
+ *ref_objectid = btrfs_ref_objectid_v0(leaf, ref0);
+ break;
+ }
+ return 0;
+}
+#endif
+
+/*
+ * helper to add a tree block to the list.
+ * the major work is getting the generation and level of the block
+ */
+static int add_tree_block(struct reloc_control *rc,
+ struct btrfs_key *extent_key,
+ struct btrfs_path *path,
+ struct rb_root *blocks)
+{
+ struct extent_buffer *eb;
+ struct btrfs_extent_item *ei;
+ struct btrfs_tree_block_info *bi;
+ struct tree_block *block;
+ struct rb_node *rb_node;
+ u32 item_size;
+ int level = -1;
+ int generation;
+
+ eb = path->nodes[0];
+ item_size = btrfs_item_size_nr(eb, path->slots[0]);
+
+ if (item_size >= sizeof(*ei) + sizeof(*bi)) {
+ ei = btrfs_item_ptr(eb, path->slots[0],
+ struct btrfs_extent_item);
+ bi = (struct btrfs_tree_block_info *)(ei + 1);
+ generation = btrfs_extent_generation(eb, ei);
+ level = btrfs_tree_block_level(eb, bi);
+ } else {
+#ifdef BTRFS_COMPAT_EXTENT_TREE_V0
+ u64 ref_owner;
+ int ret;
+
+ BUG_ON(item_size != sizeof(struct btrfs_extent_item_v0));
+ ret = get_ref_objectid_v0(rc, path, extent_key,
+ &ref_owner, NULL);
+ BUG_ON(ref_owner >= BTRFS_MAX_LEVEL);
+ level = (int)ref_owner;
+ /* FIXME: get real generation */
+ generation = 0;
+#else
+ BUG();
+#endif
+ }
+
+ btrfs_release_path(rc->extent_root, path);
+
+ BUG_ON(level == -1);
+
+ block = kmalloc(sizeof(*block), GFP_NOFS);
+ if (!block)
+ return -ENOMEM;
+
+ block->bytenr = extent_key->objectid;
+ block->key.objectid = extent_key->offset;
+ block->key.offset = generation;
+ block->level = level;
+ block->key_ready = 0;
+
+ rb_node = tree_insert(blocks, block->bytenr, &block->rb_node);
+ BUG_ON(rb_node);
+
+ return 0;
+}
+
+/*
+ * helper to add tree blocks for backref of type BTRFS_SHARED_DATA_REF_KEY
+ */
+static int __add_tree_block(struct reloc_control *rc,
+ u64 bytenr, u32 blocksize,
+ struct rb_root *blocks)
+{
+ struct btrfs_path *path;
+ struct btrfs_key key;
+ int ret;
+
+ if (tree_block_processed(bytenr, blocksize, rc))
+ return 0;
+
+ if (tree_search(blocks, bytenr))
+ return 0;
+
+ path = btrfs_alloc_path();
+ if (!path)
+ return -ENOMEM;
+
+ key.objectid = bytenr;
+ key.type = BTRFS_EXTENT_ITEM_KEY;
+ key.offset = blocksize;
+
+ path->search_commit_root = 1;
+ path->skip_locking = 1;
+ ret = btrfs_search_slot(NULL, rc->extent_root, &key, path, 0, 0);
+ if (ret < 0)
+ goto out;
+ BUG_ON(ret);
+
+ btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
+ ret = add_tree_block(rc, &key, path, blocks);
+out:
+ btrfs_free_path(path);
+ return ret;
+}
+
+/*
+ * helper to check if the block use full backrefs for pointers in it
+ */
+static int block_use_full_backref(struct reloc_control *rc,
+ struct extent_buffer *eb)
+{
+ struct btrfs_path *path;
+ struct btrfs_extent_item *ei;
+ struct btrfs_key key;
+ u64 flags;
+ int ret;
+
+ if (btrfs_header_flag(eb, BTRFS_HEADER_FLAG_RELOC) ||
+ btrfs_header_backref_rev(eb) < BTRFS_MIXED_BACKREF_REV)
+ return 1;
+
+ path = btrfs_alloc_path();
+ BUG_ON(!path);
+
+ key.objectid = eb->start;
+ key.type = BTRFS_EXTENT_ITEM_KEY;
+ key.offset = eb->len;
+
+ path->search_commit_root = 1;
+ path->skip_locking = 1;
+ ret = btrfs_search_slot(NULL, rc->extent_root,
+ &key, path, 0, 0);
+ BUG_ON(ret);
+
+ ei = btrfs_item_ptr(path->nodes[0], path->slots[0],
+ struct btrfs_extent_item);
+ flags = btrfs_extent_flags(path->nodes[0], ei);
+ BUG_ON(!(flags & BTRFS_EXTENT_FLAG_TREE_BLOCK));
+ if (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF)
+ ret = 1;
+ else
+ ret = 0;
+ btrfs_free_path(path);
+ return ret;
+}
+
+/*
+ * helper to add tree blocks for backref of type BTRFS_EXTENT_DATA_REF_KEY
+ * this function scans fs tree to find blocks reference the data extent
+ */
+static int find_data_references(struct reloc_control *rc,
+ struct btrfs_key *extent_key,
+ struct extent_buffer *leaf,
+ struct btrfs_extent_data_ref *ref,
+ struct rb_root *blocks)
+{
+ struct btrfs_path *path;
+ struct tree_block *block;
+ struct btrfs_root *root;
+ struct btrfs_file_extent_item *fi;
+ struct rb_node *rb_node;
+ struct btrfs_key key;
+ u64 ref_root;
+ u64 ref_objectid;
+ u64 ref_offset;
+ u32 ref_count;
+ u32 nritems;
+ int err = 0;
+ int added = 0;
+ int counted;
+ int ret;
+
+ path = btrfs_alloc_path();
+ if (!path)
+ return -ENOMEM;
+
+ ref_root = btrfs_extent_data_ref_root(leaf, ref);
+ ref_objectid = btrfs_extent_data_ref_objectid(leaf, ref);
+ ref_offset = btrfs_extent_data_ref_offset(leaf, ref);
+ ref_count = btrfs_extent_data_ref_count(leaf, ref);
+
+ root = read_fs_root(rc->extent_root->fs_info, ref_root);
+ if (IS_ERR(root)) {
+ err = PTR_ERR(root);
+ goto out;
+ }
+
+ key.objectid = ref_objectid;
+ key.offset = ref_offset;
+ key.type = BTRFS_EXTENT_DATA_KEY;
+
+ path->search_commit_root = 1;
+ path->skip_locking = 1;
+ ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
+ if (ret < 0) {
+ err = ret;
+ goto out;
+ }
+
+ leaf = path->nodes[0];
+ nritems = btrfs_header_nritems(leaf);
+ /*
+ * the references in tree blocks that use full backrefs
+ * are not counted in
+ */
+ if (block_use_full_backref(rc, leaf))
+ counted = 0;
+ else
+ counted = 1;
+ rb_node = tree_search(blocks, leaf->start);
+ if (rb_node) {
+ if (counted)
+ added = 1;
+ else
+ path->slots[0] = nritems;
+ }
+
+ while (ref_count > 0) {
+ while (path->slots[0] >= nritems) {
+ ret = btrfs_next_leaf(root, path);
+ if (ret < 0) {
+ err = ret;
+ goto out;
+ }
+ if (ret > 0) {
+ WARN_ON(1);
+ goto out;
+ }
+
+ leaf = path->nodes[0];
+ nritems = btrfs_header_nritems(leaf);
+ added = 0;
+
+ if (block_use_full_backref(rc, leaf))
+ counted = 0;
+ else
+ counted = 1;
+ rb_node = tree_search(blocks, leaf->start);
+ if (rb_node) {
+ if (counted)
+ added = 1;
+ else
+ path->slots[0] = nritems;
+ }
+ }
+
+ btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
+ if (key.objectid != ref_objectid ||
+ key.type != BTRFS_EXTENT_DATA_KEY) {
+ WARN_ON(1);
+ break;
+ }
+
+ fi = btrfs_item_ptr(leaf, path->slots[0],
+ struct btrfs_file_extent_item);
+
+ if (btrfs_file_extent_type(leaf, fi) ==
+ BTRFS_FILE_EXTENT_INLINE)
+ goto next;
+
+ if (btrfs_file_extent_disk_bytenr(leaf, fi) !=
+ extent_key->objectid)
+ goto next;
+
+ key.offset -= btrfs_file_extent_offset(leaf, fi);
+ if (key.offset != ref_offset)
+ goto next;
+
+ if (counted)
+ ref_count--;
+ if (added)
+ goto next;
+
+ if (!tree_block_processed(leaf->start, leaf->len, rc)) {
+ block = kmalloc(sizeof(*block), GFP_NOFS);
+ if (!block) {
+ err = -ENOMEM;
+ break;
+ }
+ block->bytenr = leaf->start;
+ btrfs_item_key_to_cpu(leaf, &block->key, 0);
+ block->level = 0;
+ block->key_ready = 1;
+ rb_node = tree_insert(blocks, block->bytenr,
+ &block->rb_node);
+ BUG_ON(rb_node);
+ }
+ if (counted)
+ added = 1;
+ else
+ path->slots[0] = nritems;
+next:
+ path->slots[0]++;
+
+ }
+out:
+ btrfs_free_path(path);
+ return err;
+}
+
+/*
+ * hepler to find all tree blocks that reference a given data extent
+ */
+static noinline_for_stack
+int add_data_references(struct reloc_control *rc,
+ struct btrfs_key *extent_key,
+ struct btrfs_path *path,
+ struct rb_root *blocks)
+{
+ struct btrfs_key key;
+ struct extent_buffer *eb;
+ struct btrfs_extent_data_ref *dref;
+ struct btrfs_extent_inline_ref *iref;
+ unsigned long ptr;
+ unsigned long end;
+ u32 blocksize;
+ int ret;
+ int err = 0;
+
+ ret = get_new_location(rc->data_inode, NULL, extent_key->objectid,
+ extent_key->offset);
+ BUG_ON(ret < 0);
+ if (ret > 0) {
+ /* the relocated data is fragmented */
+ rc->extents_skipped++;
+ btrfs_release_path(rc->extent_root, path);
+ return 0;
+ }
+
+ blocksize = btrfs_level_size(rc->extent_root, 0);
+
+ eb = path->nodes[0];
+ ptr = btrfs_item_ptr_offset(eb, path->slots[0]);
+ end = ptr + btrfs_item_size_nr(eb, path->slots[0]);
+#ifdef BTRFS_COMPAT_EXTENT_TREE_V0
+ if (ptr + sizeof(struct btrfs_extent_item_v0) == end)
+ ptr = end;
+ else
+#endif
+ ptr += sizeof(struct btrfs_extent_item);
+
+ while (ptr < end) {
+ iref = (struct btrfs_extent_inline_ref *)ptr;
+ key.type = btrfs_extent_inline_ref_type(eb, iref);
+ if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
+ key.offset = btrfs_extent_inline_ref_offset(eb, iref);
+ ret = __add_tree_block(rc, key.offset, blocksize,
+ blocks);
+ } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
+ dref = (struct btrfs_extent_data_ref *)(&iref->offset);
+ ret = find_data_references(rc, extent_key,
+ eb, dref, blocks);
+ } else {
+ BUG();
+ }
+ ptr += btrfs_extent_inline_ref_size(key.type);
+ }
+ WARN_ON(ptr > end);
+
+ while (1) {
+ cond_resched();
+ eb = path->nodes[0];
+ if (path->slots[0] >= btrfs_header_nritems(eb)) {
+ ret = btrfs_next_leaf(rc->extent_root, path);
+ if (ret < 0) {
+ err = ret;
+ break;
+ }
+ if (ret > 0)
+ break;
+ eb = path->nodes[0];
+ }
+
+ btrfs_item_key_to_cpu(eb, &key, path->slots[0]);
+ if (key.objectid != extent_key->objectid)
+ break;
+
+#ifdef BTRFS_COMPAT_EXTENT_TREE_V0
+ if (key.type == BTRFS_SHARED_DATA_REF_KEY ||
+ key.type == BTRFS_EXTENT_REF_V0_KEY) {
+#else
+ BUG_ON(key.type == BTRFS_EXTENT_REF_V0_KEY);
+ if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
+#endif
+ ret = __add_tree_block(rc, key.offset, blocksize,
+ blocks);
+ } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
+ dref = btrfs_item_ptr(eb, path->slots[0],
+ struct btrfs_extent_data_ref);
+ ret = find_data_references(rc, extent_key,
+ eb, dref, blocks);
+ } else {
+ ret = 0;
+ }
+ if (ret) {
+ err = ret;
+ break;
+ }
+ path->slots[0]++;
+ }
+ btrfs_release_path(rc->extent_root, path);
+ if (err)
+ free_block_list(blocks);
+ return err;
+}
+
+/*
+ * hepler to find next unprocessed extent
+ */
+static noinline_for_stack
+int find_next_extent(struct btrfs_trans_handle *trans,
+ struct reloc_control *rc, struct btrfs_path *path)
+{
+ struct btrfs_key key;
+ struct extent_buffer *leaf;
+ u64 start, end, last;
+ int ret;
+
+ last = rc->block_group->key.objectid + rc->block_group->key.offset;
+ while (1) {
+ cond_resched();
+ if (rc->search_start >= last) {
+ ret = 1;
+ break;
+ }
+
+ key.objectid = rc->search_start;
+ key.type = BTRFS_EXTENT_ITEM_KEY;
+ key.offset = 0;
+
+ path->search_commit_root = 1;
+ path->skip_locking = 1;
+ ret = btrfs_search_slot(NULL, rc->extent_root, &key, path,
+ 0, 0);
+ if (ret < 0)
+ break;
+next:
+ leaf = path->nodes[0];
+ if (path->slots[0] >= btrfs_header_nritems(leaf)) {
+ ret = btrfs_next_leaf(rc->extent_root, path);
+ if (ret != 0)
+ break;
+ leaf = path->nodes[0];
+ }
+
+ btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
+ if (key.objectid >= last) {
+ ret = 1;
+ break;
+ }
+
+ if (key.type != BTRFS_EXTENT_ITEM_KEY ||
+ key.objectid + key.offset <= rc->search_start) {
+ path->slots[0]++;
+ goto next;
+ }
+
+ ret = find_first_extent_bit(&rc->processed_blocks,
+ key.objectid, &start, &end,
+ EXTENT_DIRTY);
+
+ if (ret == 0 && start <= key.objectid) {
+ btrfs_release_path(rc->extent_root, path);
+ rc->search_start = end + 1;
+ } else {
+ rc->search_start = key.objectid + key.offset;
+ return 0;
+ }
+ }
+ btrfs_release_path(rc->extent_root, path);
+ return ret;
+}
+
+static void set_reloc_control(struct reloc_control *rc)
+{
+ struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
+ mutex_lock(&fs_info->trans_mutex);
+ fs_info->reloc_ctl = rc;
+ mutex_unlock(&fs_info->trans_mutex);
+}
+
+static void unset_reloc_control(struct reloc_control *rc)
+{
+ struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
+ mutex_lock(&fs_info->trans_mutex);
+ fs_info->reloc_ctl = NULL;
+ mutex_unlock(&fs_info->trans_mutex);
+}
+
+static int check_extent_flags(u64 flags)
+{
+ if ((flags & BTRFS_EXTENT_FLAG_DATA) &&
+ (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK))
+ return 1;
+ if (!(flags & BTRFS_EXTENT_FLAG_DATA) &&
+ !(flags & BTRFS_EXTENT_FLAG_TREE_BLOCK))
+ return 1;
+ if ((flags & BTRFS_EXTENT_FLAG_DATA) &&
+ (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
+ return 1;
+ return 0;
+}
+
+static noinline_for_stack int relocate_block_group(struct reloc_control *rc)
+{
+ struct rb_root blocks = RB_ROOT;
+ struct btrfs_key key;
+ struct btrfs_trans_handle *trans = NULL;
+ struct btrfs_path *path;
+ struct btrfs_extent_item *ei;
+ unsigned long nr;
+ u64 flags;
+ u32 item_size;
+ int ret;
+ int err = 0;
+
+ path = btrfs_alloc_path();
+ if (!path)
+ return -ENOMEM;
+
+ rc->search_start = rc->block_group->key.objectid;
+ clear_extent_bits(&rc->processed_blocks, 0, (u64)-1, EXTENT_DIRTY,
+ GFP_NOFS);
+
+ rc->create_reloc_root = 1;
+ set_reloc_control(rc);
+
+ trans = btrfs_start_transaction(rc->extent_root, 1);
+ btrfs_commit_transaction(trans, rc->extent_root);
+
+ while (1) {
+ trans = btrfs_start_transaction(rc->extent_root, 1);
+
+ ret = find_next_extent(trans, rc, path);
+ if (ret < 0)
+ err = ret;
+ if (ret != 0)
+ break;
+
+ rc->extents_found++;
+
+ ei = btrfs_item_ptr(path->nodes[0], path->slots[0],
+ struct btrfs_extent_item);
+ btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
+ item_size = btrfs_item_size_nr(path->nodes[0],
+ path->slots[0]);
+ if (item_size >= sizeof(*ei)) {
+ flags = btrfs_extent_flags(path->nodes[0], ei);
+ ret = check_extent_flags(flags);
+ BUG_ON(ret);
+
+ } else {
+#ifdef BTRFS_COMPAT_EXTENT_TREE_V0
+ u64 ref_owner;
+ int path_change = 0;
+
+ BUG_ON(item_size !=
+ sizeof(struct btrfs_extent_item_v0));
+ ret = get_ref_objectid_v0(rc, path, &key, &ref_owner,
+ &path_change);
+ if (ref_owner < BTRFS_FIRST_FREE_OBJECTID)
+ flags = BTRFS_EXTENT_FLAG_TREE_BLOCK;
+ else
+ flags = BTRFS_EXTENT_FLAG_DATA;
+
+ if (path_change) {
+ btrfs_release_path(rc->extent_root, path);
+
+ path->search_commit_root = 1;
+ path->skip_locking = 1;
+ ret = btrfs_search_slot(NULL, rc->extent_root,
+ &key, path, 0, 0);
+ if (ret < 0) {
+ err = ret;
+ break;
+ }
+ BUG_ON(ret > 0);
+ }
+#else
+ BUG();
+#endif
+ }
+
+ if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
+ ret = add_tree_block(rc, &key, path, &blocks);
+ } else if (rc->stage == UPDATE_DATA_PTRS &&
+ (flags & BTRFS_EXTENT_FLAG_DATA)) {
+ ret = add_data_references(rc, &key, path, &blocks);
+ } else {
+ btrfs_release_path(rc->extent_root, path);
+ ret = 0;
+ }
+ if (ret < 0) {
+ err = 0;
+ break;
+ }
+
+ if (!RB_EMPTY_ROOT(&blocks)) {
+ ret = relocate_tree_blocks(trans, rc, &blocks);
+ if (ret < 0) {
+ err = ret;
+ break;
+ }
+ }
+
+ nr = trans->blocks_used;
+ btrfs_end_transaction_throttle(trans, rc->extent_root);
+ trans = NULL;
+ btrfs_btree_balance_dirty(rc->extent_root, nr);
+
+ if (rc->stage == MOVE_DATA_EXTENTS &&
+ (flags & BTRFS_EXTENT_FLAG_DATA)) {
+ rc->found_file_extent = 1;
+ ret = relocate_data_extent(rc->data_inode, &key);
+ if (ret < 0) {
+ err = ret;
+ break;
+ }
+ }
+ }
+ btrfs_free_path(path);
+
+ if (trans) {
+ nr = trans->blocks_used;
+ btrfs_end_transaction(trans, rc->extent_root);
+ btrfs_btree_balance_dirty(rc->extent_root, nr);
+ }
+
+ rc->create_reloc_root = 0;
+ smp_mb();
+
+ if (rc->extents_found > 0) {
+ trans = btrfs_start_transaction(rc->extent_root, 1);
+ btrfs_commit_transaction(trans, rc->extent_root);
+ }
+
+ merge_reloc_roots(rc);
+
+ unset_reloc_control(rc);
+
+ /* get rid of pinned extents */
+ trans = btrfs_start_transaction(rc->extent_root, 1);
+ btrfs_commit_transaction(trans, rc->extent_root);
+
+ return err;
+}
+
+static int __insert_orphan_inode(struct btrfs_trans_handle *trans,
+ struct btrfs_root *root,
+ u64 objectid, u64 size)
+{
+ struct btrfs_path *path;
+ struct btrfs_inode_item *item;
+ struct extent_buffer *leaf;
+ int ret;
+
+ path = btrfs_alloc_path();
+ if (!path)
+ return -ENOMEM;
+
+ ret = btrfs_insert_empty_inode(trans, root, path, objectid);
+ if (ret)
+ goto out;
+
+ leaf = path->nodes[0];
+ item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_inode_item);
+ memset_extent_buffer(leaf, 0, (unsigned long)item, sizeof(*item));
+ btrfs_set_inode_generation(leaf, item, 1);
+ btrfs_set_inode_size(leaf, item, size);
+ btrfs_set_inode_mode(leaf, item, S_IFREG | 0600);
+ btrfs_set_inode_flags(leaf, item, BTRFS_INODE_NOCOMPRESS);
+ btrfs_mark_buffer_dirty(leaf);
+ btrfs_release_path(root, path);
+out:
+ btrfs_free_path(path);
+ return ret;
+}
+
+/*
+ * helper to create inode for data relocation.
+ * the inode is in data relocation tree and its link count is 0
+ */
+static struct inode *create_reloc_inode(struct btrfs_fs_info *fs_info,
+ struct btrfs_block_group_cache *group)
+{
+ struct inode *inode = NULL;
+ struct btrfs_trans_handle *trans;
+ struct btrfs_root *root;
+ struct btrfs_key key;
+ unsigned long nr;
+ u64 objectid = BTRFS_FIRST_FREE_OBJECTID;
+ int err = 0;
+
+ root = read_fs_root(fs_info, BTRFS_DATA_RELOC_TREE_OBJECTID);
+ if (IS_ERR(root))
+ return ERR_CAST(root);
+
+ trans = btrfs_start_transaction(root, 1);
+ BUG_ON(!trans);
+
+ err = btrfs_find_free_objectid(trans, root, objectid, &objectid);
+ if (err)
+ goto out;
+
+ err = __insert_orphan_inode(trans, root, objectid, group->key.offset);
+ BUG_ON(err);
+
+ err = btrfs_insert_file_extent(trans, root, objectid, 0, 0, 0,
+ group->key.offset, 0, group->key.offset,
+ 0, 0, 0);
+ BUG_ON(err);
+
+ key.objectid = objectid;
+ key.type = BTRFS_INODE_ITEM_KEY;
+ key.offset = 0;
+ inode = btrfs_iget(root->fs_info->sb, &key, root);
+ BUG_ON(IS_ERR(inode) || is_bad_inode(inode));
+ BTRFS_I(inode)->index_cnt = group->key.objectid;
+
+ err = btrfs_orphan_add(trans, inode);
+out:
+ nr = trans->blocks_used;
+ btrfs_end_transaction(trans, root);
+
+ btrfs_btree_balance_dirty(root, nr);
+ if (err) {
+ if (inode)
+ iput(inode);
+ inode = ERR_PTR(err);
+ }
+ return inode;
+}
+
+/*
+ * function to relocate all extents in a block group.
+ */
+int btrfs_relocate_block_group(struct btrfs_root *extent_root, u64 group_start)
+{
+ struct btrfs_fs_info *fs_info = extent_root->fs_info;
+ struct reloc_control *rc;
+ int ret;
+ int err = 0;
+
+ rc = kzalloc(sizeof(*rc), GFP_NOFS);
+ if (!rc)
+ return -ENOMEM;
+
+ mapping_tree_init(&rc->reloc_root_tree);
+ extent_io_tree_init(&rc->processed_blocks, NULL, GFP_NOFS);
+ INIT_LIST_HEAD(&rc->reloc_roots);
+
+ rc->block_group = btrfs_lookup_block_group(fs_info, group_start);
+ BUG_ON(!rc->block_group);
+
+ btrfs_init_workers(&rc->workers, "relocate",
+ fs_info->thread_pool_size);
+
+ rc->extent_root = extent_root;
+ btrfs_prepare_block_group_relocation(extent_root, rc->block_group);
+
+ rc->data_inode = create_reloc_inode(fs_info, rc->block_group);
+ if (IS_ERR(rc->data_inode)) {
+ err = PTR_ERR(rc->data_inode);
+ rc->data_inode = NULL;
+ goto out;
+ }
+
+ printk(KERN_INFO "btrfs: relocating block group %llu flags %llu\n",
+ (unsigned long long)rc->block_group->key.objectid,
+ (unsigned long long)rc->block_group->flags);
+
+ btrfs_start_delalloc_inodes(fs_info->tree_root);
+ btrfs_wait_ordered_extents(fs_info->tree_root, 0);
+
+ while (1) {
+ mutex_lock(&fs_info->cleaner_mutex);
+ btrfs_clean_old_snapshots(fs_info->tree_root);
+ mutex_unlock(&fs_info->cleaner_mutex);
+
+ rc->extents_found = 0;
+ rc->extents_skipped = 0;
+
+ ret = relocate_block_group(rc);
+ if (ret < 0) {
+ err = ret;
+ break;
+ }
+
+ if (rc->extents_found == 0)
+ break;
+
+ printk(KERN_INFO "btrfs: found %llu extents\n",
+ (unsigned long long)rc->extents_found);
+
+ if (rc->stage == MOVE_DATA_EXTENTS && rc->found_file_extent) {
+ btrfs_wait_ordered_range(rc->data_inode, 0, (u64)-1);
+ invalidate_mapping_pages(rc->data_inode->i_mapping,
+ 0, -1);
+ rc->stage = UPDATE_DATA_PTRS;
+ } else if (rc->stage == UPDATE_DATA_PTRS &&
+ rc->extents_skipped >= rc->extents_found) {
+ iput(rc->data_inode);
+ rc->data_inode = create_reloc_inode(fs_info,
+ rc->block_group);
+ if (IS_ERR(rc->data_inode)) {
+ err = PTR_ERR(rc->data_inode);
+ rc->data_inode = NULL;
+ break;
+ }
+ rc->stage = MOVE_DATA_EXTENTS;
+ rc->found_file_extent = 0;
+ }
+ }
+
+ filemap_fdatawrite_range(fs_info->btree_inode->i_mapping,
+ rc->block_group->key.objectid,
+ rc->block_group->key.objectid +
+ rc->block_group->key.offset - 1);
+
+ WARN_ON(rc->block_group->pinned > 0);
+ WARN_ON(rc->block_group->reserved > 0);
+ WARN_ON(btrfs_block_group_used(&rc->block_group->item) > 0);
+out:
+ iput(rc->data_inode);
+ btrfs_stop_workers(&rc->workers);
+ btrfs_put_block_group(rc->block_group);
+ kfree(rc);
+ return err;
+}
+
+/*
+ * recover relocation interrupted by system crash.
+ *
+ * this function resumes merging reloc trees with corresponding fs trees.
+ * this is important for keeping the sharing of tree blocks
+ */
+int btrfs_recover_relocation(struct btrfs_root *root)
+{
+ LIST_HEAD(reloc_roots);
+ struct btrfs_key key;
+ struct btrfs_root *fs_root;
+ struct btrfs_root *reloc_root;
+ struct btrfs_path *path;
+ struct extent_buffer *leaf;
+ struct reloc_control *rc = NULL;
+ struct btrfs_trans_handle *trans;
+ int ret;
+ int err = 0;
+
+ path = btrfs_alloc_path();
+ if (!path)
+ return -ENOMEM;
+
+ key.objectid = BTRFS_TREE_RELOC_OBJECTID;
+ key.type = BTRFS_ROOT_ITEM_KEY;
+ key.offset = (u64)-1;
+
+ while (1) {
+ ret = btrfs_search_slot(NULL, root->fs_info->tree_root, &key,
+ path, 0, 0);
+ if (ret < 0) {
+ err = ret;
+ goto out;
+ }
+ if (ret > 0) {
+ if (path->slots[0] == 0)
+ break;
+ path->slots[0]--;
+ }
+ leaf = path->nodes[0];
+ btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
+ btrfs_release_path(root->fs_info->tree_root, path);
+
+ if (key.objectid != BTRFS_TREE_RELOC_OBJECTID ||
+ key.type != BTRFS_ROOT_ITEM_KEY)
+ break;
+
+ reloc_root = btrfs_read_fs_root_no_radix(root, &key);
+ if (IS_ERR(reloc_root)) {
+ err = PTR_ERR(reloc_root);
+ goto out;
+ }
+
+ list_add(&reloc_root->root_list, &reloc_roots);
+
+ if (btrfs_root_refs(&reloc_root->root_item) > 0) {
+ fs_root = read_fs_root(root->fs_info,
+ reloc_root->root_key.offset);
+ if (IS_ERR(fs_root)) {
+ err = PTR_ERR(fs_root);
+ goto out;
+ }
+ }
+
+ if (key.offset == 0)
+ break;
+
+ key.offset--;
+ }
+ btrfs_release_path(root->fs_info->tree_root, path);
+
+ if (list_empty(&reloc_roots))
+ goto out;
+
+ rc = kzalloc(sizeof(*rc), GFP_NOFS);
+ if (!rc) {
+ err = -ENOMEM;
+ goto out;
+ }
+
+ mapping_tree_init(&rc->reloc_root_tree);
+ INIT_LIST_HEAD(&rc->reloc_roots);
+ btrfs_init_workers(&rc->workers, "relocate",
+ root->fs_info->thread_pool_size);
+ rc->extent_root = root->fs_info->extent_root;
+
+ set_reloc_control(rc);
+
+ while (!list_empty(&reloc_roots)) {
+ reloc_root = list_entry(reloc_roots.next,
+ struct btrfs_root, root_list);
+ list_del(&reloc_root->root_list);
+
+ if (btrfs_root_refs(&reloc_root->root_item) == 0) {
+ list_add_tail(&reloc_root->root_list,
+ &rc->reloc_roots);
+ continue;
+ }
+
+ fs_root = read_fs_root(root->fs_info,
+ reloc_root->root_key.offset);
+ BUG_ON(IS_ERR(fs_root));
+
+ __add_reloc_root(reloc_root);
+ fs_root->reloc_root = reloc_root;
+ }
+
+ trans = btrfs_start_transaction(rc->extent_root, 1);
+ btrfs_commit_transaction(trans, rc->extent_root);
+
+ merge_reloc_roots(rc);
+
+ unset_reloc_control(rc);
+
+ trans = btrfs_start_transaction(rc->extent_root, 1);
+ btrfs_commit_transaction(trans, rc->extent_root);
+out:
+ if (rc) {
+ btrfs_stop_workers(&rc->workers);
+ kfree(rc);
+ }
+ while (!list_empty(&reloc_roots)) {
+ reloc_root = list_entry(reloc_roots.next,
+ struct btrfs_root, root_list);
+ list_del(&reloc_root->root_list);
+ free_extent_buffer(reloc_root->node);
+ free_extent_buffer(reloc_root->commit_root);
+ kfree(reloc_root);
+ }
+ btrfs_free_path(path);
+
+ if (err == 0) {
+ /* cleanup orphan inode in data relocation tree */
+ fs_root = read_fs_root(root->fs_info,
+ BTRFS_DATA_RELOC_TREE_OBJECTID);
+ if (IS_ERR(fs_root))
+ err = PTR_ERR(fs_root);
+ }
+ return err;
+}
+
+/*
+ * helper to add ordered checksum for data relocation.
+ *
+ * cloning checksum properly handles the nodatasum extents.
+ * it also saves CPU time to re-calculate the checksum.
+ */
+int btrfs_reloc_clone_csums(struct inode *inode, u64 file_pos, u64 len)
+{
+ struct btrfs_ordered_sum *sums;
+ struct btrfs_sector_sum *sector_sum;
+ struct btrfs_ordered_extent *ordered;
+ struct btrfs_root *root = BTRFS_I(inode)->root;
+ size_t offset;
+ int ret;
+ u64 disk_bytenr;
+ LIST_HEAD(list);
+
+ ordered = btrfs_lookup_ordered_extent(inode, file_pos);
+ BUG_ON(ordered->file_offset != file_pos || ordered->len != len);
+
+ disk_bytenr = file_pos + BTRFS_I(inode)->index_cnt;
+ ret = btrfs_lookup_csums_range(root->fs_info->csum_root, disk_bytenr,
+ disk_bytenr + len - 1, &list);
+
+ while (!list_empty(&list)) {
+ sums = list_entry(list.next, struct btrfs_ordered_sum, list);
+ list_del_init(&sums->list);
+
+ sector_sum = sums->sums;
+ sums->bytenr = ordered->start;
+
+ offset = 0;
+ while (offset < sums->len) {
+ sector_sum->bytenr += ordered->start - disk_bytenr;
+ sector_sum++;
+ offset += root->sectorsize;
+ }
+
+ btrfs_add_ordered_sum(inode, ordered, sums);
+ }
+ btrfs_put_ordered_extent(ordered);
+ return 0;
+}
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