/* * 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; }; #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_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; } if (ret > 0 && path2->slots[level] > 0) path2->slots[level]--; 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 void put_inodes(struct list_head *list) { struct inodevec *ivec; while (!list_empty(list)) { ivec = list_entry(list->next, struct inodevec, list); list_del(&ivec->list); while (ivec->nr > 0) { ivec->nr--; iput(ivec->inode[ivec->nr]); } kfree(ivec); } } 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); 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); } 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); /* * put inodes outside transaction, otherwise we may deadlock. */ put_inodes(&inode_list); 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(&inode_list); 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_snapshot(reloc_root, 0); if (atomic_dec_and_test(async->num_pending)) complete(async->done); kfree(async); } static int merge_reloc_roots(struct reloc_control *rc) { struct async_merge *async; struct btrfs_root *root; struct completion done; atomic_t num_pending; init_completion(&done); atomic_set(&num_pending, 1); while (!list_empty(&rc->reloc_roots)) { root = list_entry(rc->reloc_roots.next, struct btrfs_root, root_list); list_del_init(&root->root_list); async = kmalloc(sizeof(*async), GFP_NOFS); BUG_ON(!async); async->work.func = merge_func; async->work.flags = 0; async->rc = rc; async->root = root; async->done = &done; async->num_pending = &num_pending; atomic_inc(&num_pending); btrfs_queue_worker(&rc->workers, &async->work); } if (!atomic_dec_and_test(&num_pending)) wait_for_completion(&done); BUG_ON(!RB_EMPTY_ROOT(&rc->reloc_root_tree.rb_root)); return 0; } static void free_block_list(struct rb_root *blocks) { struct tree_block *block; struct rb_node *rb_node; while ((rb_node = rb_first(blocks))) { block = rb_entry(rb_node, struct tree_block, rb_node); rb_erase(rb_node, blocks); kfree(block); } } static int record_reloc_root_in_trans(struct btrfs_trans_handle *trans, struct btrfs_root *reloc_root) { struct btrfs_root *root; if (reloc_root->last_trans == trans->transid) return 0; root = read_fs_root(reloc_root->fs_info, reloc_root->root_key.offset); BUG_ON(IS_ERR(root)); BUG_ON(root->reloc_root != reloc_root); return btrfs_record_root_in_trans(trans, root); } /* * select one tree from trees that references the block. * for blocks in refernce counted trees, we preper reloc tree. * if no reloc tree found and reloc_only is true, NULL is returned. */ static struct btrfs_root *__select_one_root(struct btrfs_trans_handle *trans, struct backref_node *node, struct backref_edge *edges[], int *nr, int reloc_only) { struct backref_node *next; struct btrfs_root *root; int index; int loop = 0; again: index = 0; next = node; while (1) { cond_resched(); next = walk_up_backref(next, edges, &index); root = next->root; if (!root) { BUG_ON(!node->old_root); goto skip; } /* no other choice for non-refernce counted tree */ if (!root->ref_cows) { BUG_ON(reloc_only); break; } if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) { record_reloc_root_in_trans(trans, root); break; } if (loop) { btrfs_record_root_in_trans(trans, root); break; } if (reloc_only || next != node) { if (!root->reloc_root) btrfs_record_root_in_trans(trans, root); root = root->reloc_root; /* * if the reloc tree was created in current * transation, there is no node in backref tree * corresponds to the root of the reloc tree. */ if (btrfs_root_last_snapshot(&root->root_item) == trans->transid - 1) break; } skip: root = NULL; next = walk_down_backref(edges, &index); if (!next || next->level <= node->level) break; } if (!root && !loop && !reloc_only) { loop = 1; goto again; } if (root) *nr = index; else *nr = 0; return root; } static noinline_for_stack struct btrfs_root *select_one_root(struct btrfs_trans_handle *trans, struct backref_node *node) { struct backref_edge *edges[BTRFS_MAX_LEVEL - 1]; int nr; return __select_one_root(trans, node, edges, &nr, 0); } static noinline_for_stack struct btrfs_root *select_reloc_root(struct btrfs_trans_handle *trans, struct backref_node *node, struct backref_edge *edges[], int *nr) { return __select_one_root(trans, node, edges, nr, 1); } static void grab_path_buffers(struct btrfs_path *path, struct backref_node *node, struct backref_edge *edges[], int nr) { int i = 0; while (1) { drop_node_buffer(node); node->eb = path->nodes[node->level]; BUG_ON(!node->eb); if (path->locks[node->level]) node->locked = 1; path->nodes[node->level] = NULL; path->locks[node->level] = 0; if (i >= nr) break; edges[i]->blockptr = node->eb->start; node = edges[i]->node[UPPER]; i++; } } /* * relocate a block tree, and then update pointers in upper level * blocks that reference the block to point to the new location. * * if called by link_to_upper, the block has already been relocated. * in that case this function just updates pointers. */ static int do_relocation(struct btrfs_trans_handle *trans, struct backref_node *node, struct btrfs_key *key, struct btrfs_path *path, int lowest) { struct backref_node *upper; struct backref_edge *edge; struct backref_edge *edges[BTRFS_MAX_LEVEL - 1]; struct btrfs_root *root; struct extent_buffer *eb; u32 blocksize; u64 bytenr; u64 generation; int nr; int slot; int ret; int err = 0; BUG_ON(lowest && node->eb); path->lowest_level = node->level + 1; list_for_each_entry(edge, &node->upper, list[LOWER]) { cond_resched(); if (node->eb && node->eb->start == edge->blockptr) continue; upper = edge->node[UPPER]; root = select_reloc_root(trans, upper, edges, &nr); if (!root) continue; if (upper->eb && !upper->locked) drop_node_buffer(upper); if (!upper->eb) { ret = btrfs_search_slot(trans, root, key, path, 0, 1); if (ret < 0) { err = ret; break; } BUG_ON(ret > 0); slot = path->slots[upper->level]; btrfs_unlock_up_safe(path, upper->level + 1); grab_path_buffers(path, upper, edges, nr); btrfs_release_path(NULL, path); } else { ret = btrfs_bin_search(upper->eb, key, upper->level, &slot); BUG_ON(ret); } bytenr = btrfs_node_blockptr(upper->eb, slot); if (!lowest) { if (node->eb->start == bytenr) { btrfs_tree_unlock(upper->eb); upper->locked = 0; continue; } } else { BUG_ON(node->bytenr != bytenr); } blocksize = btrfs_level_size(root, node->level); generation = btrfs_node_ptr_generation(upper->eb, slot); eb = read_tree_block(root, bytenr, blocksize, generation); btrfs_tree_lock(eb); btrfs_set_lock_blocking(eb); if (!node->eb) { ret = btrfs_cow_block(trans, root, eb, upper->eb, slot, &eb); if (ret < 0) { err = ret; break; } btrfs_set_lock_blocking(eb); node->eb = eb; node->locked = 1; } else { btrfs_set_node_blockptr(upper->eb, slot, node->eb->start); btrfs_set_node_ptr_generation(upper->eb, slot, trans->transid); btrfs_mark_buffer_dirty(upper->eb); ret = btrfs_inc_extent_ref(trans, root, node->eb->start, blocksize, upper->eb->start, btrfs_header_owner(upper->eb), node->level, 0); BUG_ON(ret); ret = btrfs_drop_subtree(trans, root, eb, upper->eb); BUG_ON(ret); } if (!lowest) { btrfs_tree_unlock(upper->eb); upper->locked = 0; } } path->lowest_level = 0; return err; } static int link_to_upper(struct btrfs_trans_handle *trans, struct backref_node *node, struct btrfs_path *path) { struct btrfs_key key; if (!node->eb || list_empty(&node->upper)) return 0; btrfs_node_key_to_cpu(node->eb, &key, 0); return do_relocation(trans, node, &key, path, 0); } static int finish_pending_nodes(struct btrfs_trans_handle *trans, struct backref_cache *cache, struct btrfs_path *path) { struct backref_node *node; int level; int ret; int err = 0; for (level = 0; level < BTRFS_MAX_LEVEL; level++) { while (!list_empty(&cache->pending[level])) { node = list_entry(cache->pending[level].next, struct backref_node, lower); BUG_ON(node->level != level); ret = link_to_upper(trans, node, path); if (ret < 0) err = ret; /* * this remove the node from the pending list and * may add some other nodes to the level + 1 * pending list */ remove_backref_node(cache, node); } } BUG_ON(!RB_EMPTY_ROOT(&cache->rb_root)); return err; } static void mark_block_processed(struct reloc_control *rc, struct backref_node *node) { u32 blocksize; if (node->level == 0 || in_block_group(node->bytenr, rc->block_group)) { blocksize = btrfs_level_size(rc->extent_root, node->level); set_extent_bits(&rc->processed_blocks, node->bytenr, node->bytenr + blocksize - 1, EXTENT_DIRTY, GFP_NOFS); } node->processed = 1; } /* * mark a block and all blocks directly/indirectly reference the block * as processed. */ static void update_processed_blocks(struct reloc_control *rc, struct backref_node *node) { struct backref_node *next = node; struct backref_edge *edge; struct backref_edge *edges[BTRFS_MAX_LEVEL - 1]; int index = 0; while (next) { cond_resched(); while (1) { if (next->processed) break; mark_block_processed(rc, next); if (list_empty(&next->upper)) break; edge = list_entry(next->upper.next, struct backref_edge, list[LOWER]); edges[index++] = edge; next = edge->node[UPPER]; } next = walk_down_backref(edges, &index); } } static int tree_block_processed(u64 bytenr, u32 blocksize, struct reloc_control *rc) { if (test_range_bit(&rc->processed_blocks, bytenr, bytenr + blocksize - 1, EXTENT_DIRTY, 1, NULL)) 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 setup_extent_mapping(struct inode *inode, u64 start, u64 end, u64 block_start) { struct btrfs_root *root = BTRFS_I(inode)->root; struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree; struct extent_map *em; int ret = 0; em = alloc_extent_map(GFP_NOFS); if (!em) return -ENOMEM; em->start = start; em->len = end + 1 - start; em->block_len = em->len; em->block_start = block_start; em->bdev = root->fs_info->fs_devices->latest_bdev; set_bit(EXTENT_FLAG_PINNED, &em->flags); lock_extent(&BTRFS_I(inode)->io_tree, start, end, GFP_NOFS); while (1) { write_lock(&em_tree->lock); ret = add_extent_mapping(em_tree, em); write_unlock(&em_tree->lock); if (ret != -EEXIST) { free_extent_map(em); break; } btrfs_drop_extent_cache(inode, start, end, 0); } unlock_extent(&BTRFS_I(inode)->io_tree, start, end, GFP_NOFS); return ret; } static int relocate_file_extent_cluster(struct inode *inode, struct file_extent_cluster *cluster) { u64 page_start; u64 page_end; u64 offset = BTRFS_I(inode)->index_cnt; unsigned long index; unsigned long last_index; unsigned int dirty_page = 0; struct page *page; struct file_ra_state *ra; int nr = 0; int ret = 0; if (!cluster->nr) return 0; ra = kzalloc(sizeof(*ra), GFP_NOFS); if (!ra) return -ENOMEM; index = (cluster->start - offset) >> PAGE_CACHE_SHIFT; last_index = (cluster->end - offset) >> PAGE_CACHE_SHIFT; mutex_lock(&inode->i_mutex); i_size_write(inode, cluster->end + 1 - offset); ret = setup_extent_mapping(inode, cluster->start - offset, cluster->end - offset, cluster->start); if (ret) goto out_unlock; file_ra_state_init(ra, inode->i_mapping); WARN_ON(cluster->start != cluster->boundary[0]); while (index <= last_index) { 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 = grab_cache_page(inode->i_mapping, index); if (!page) { ret = -ENOMEM; goto out_unlock; } } 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); page_cache_release(page); ret = -EIO; goto out_unlock; } } page_start = (u64)page->index << PAGE_CACHE_SHIFT; page_end = page_start + PAGE_CACHE_SIZE - 1; lock_extent(&BTRFS_I(inode)->io_tree, page_start, page_end, GFP_NOFS); 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, GFP_NOFS); nr++; } btrfs_set_extent_delalloc(inode, page_start, page_end); set_page_dirty(page); dirty_page++; unlock_extent(&BTRFS_I(inode)->io_tree, page_start, page_end, GFP_NOFS); unlock_page(page); page_cache_release(page); index++; if (nr < cluster->nr && page_end + 1 + offset == cluster->boundary[nr]) { balance_dirty_pages_ratelimited_nr(inode->i_mapping, dirty_page); dirty_page = 0; } } if (dirty_page) { balance_dirty_pages_ratelimited_nr(inode->i_mapping, dirty_page); } WARN_ON(nr != cluster->nr); out_unlock: mutex_unlock(&inode->i_mutex); 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; } #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 file_extent_cluster *cluster; 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; cluster = kzalloc(sizeof(*cluster), GFP_NOFS); if (!cluster) return -ENOMEM; path = btrfs_alloc_path(); if (!path) return -ENOMEM; rc->extents_found = 0; rc->extents_skipped = 0; 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(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, cluster); 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); } if (!err) { ret = relocate_file_extent_cluster(rc->data_inode, cluster); if (ret < 0) err = ret; } kfree(cluster); 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) { 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, 0); 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); 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, NULL); 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, 0); btrfs_wait_ordered_extents(fs_info->tree_root, 0, 0); while (1) { rc->extents_found = 0; rc->extents_skipped = 0; mutex_lock(&fs_info->cleaner_mutex); btrfs_clean_old_snapshots(fs_info->tree_root); ret = relocate_block_group(rc); mutex_unlock(&fs_info->cleaner_mutex); 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_write_and_wait_range(fs_info->btree_inode->i_mapping, rc->block_group->key.objectid, rc->block_group->key.objectid + rc->block_group->key.offset - 1); 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; } static noinline_for_stack int mark_garbage_root(struct btrfs_root *root) { struct btrfs_trans_handle *trans; int ret; trans = btrfs_start_transaction(root->fs_info->tree_root, 1); memset(&root->root_item.drop_progress, 0, sizeof(root->root_item.drop_progress)); root->root_item.drop_level = 0; btrfs_set_root_refs(&root->root_item, 0); ret = btrfs_update_root(trans, root->fs_info->tree_root, &root->root_key, &root->root_item); BUG_ON(ret); ret = btrfs_end_transaction(trans, root->fs_info->tree_root); BUG_ON(ret); return 0; } /* * 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)) { ret = PTR_ERR(fs_root); if (ret != -ENOENT) { err = ret; goto out; } mark_garbage_root(reloc_root); } } 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, NULL); 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); 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_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; }