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- // SPDX-License-Identifier: GPL-2.0
- /*
- * Copyright (C) 2009 Oracle. All rights reserved.
- */
- #include <linux/sched.h>
- #include <linux/pagemap.h>
- #include <linux/writeback.h>
- #include <linux/blkdev.h>
- #include <linux/rbtree.h>
- #include <linux/slab.h>
- #include <linux/error-injection.h>
- #include "ctree.h"
- #include "disk-io.h"
- #include "transaction.h"
- #include "volumes.h"
- #include "locking.h"
- #include "btrfs_inode.h"
- #include "async-thread.h"
- #include "free-space-cache.h"
- #include "inode-map.h"
- #include "qgroup.h"
- #include "print-tree.h"
- #include "delalloc-space.h"
- #include "block-group.h"
- #include "backref.h"
- #include "misc.h"
- /*
- * Relocation overview
- *
- * [What does relocation do]
- *
- * The objective of relocation is to relocate all extents of the target block
- * group to other block groups.
- * This is utilized by resize (shrink only), profile converting, compacting
- * space, or balance routine to spread chunks over devices.
- *
- * Before | After
- * ------------------------------------------------------------------
- * BG A: 10 data extents | BG A: deleted
- * BG B: 2 data extents | BG B: 10 data extents (2 old + 8 relocated)
- * BG C: 1 extents | BG C: 3 data extents (1 old + 2 relocated)
- *
- * [How does relocation work]
- *
- * 1. Mark the target block group read-only
- * New extents won't be allocated from the target block group.
- *
- * 2.1 Record each extent in the target block group
- * To build a proper map of extents to be relocated.
- *
- * 2.2 Build data reloc tree and reloc trees
- * Data reloc tree will contain an inode, recording all newly relocated
- * data extents.
- * There will be only one data reloc tree for one data block group.
- *
- * Reloc tree will be a special snapshot of its source tree, containing
- * relocated tree blocks.
- * Each tree referring to a tree block in target block group will get its
- * reloc tree built.
- *
- * 2.3 Swap source tree with its corresponding reloc tree
- * Each involved tree only refers to new extents after swap.
- *
- * 3. Cleanup reloc trees and data reloc tree.
- * As old extents in the target block group are still referenced by reloc
- * trees, we need to clean them up before really freeing the target block
- * group.
- *
- * The main complexity is in steps 2.2 and 2.3.
- *
- * The entry point of relocation is relocate_block_group() function.
- */
- #define RELOCATION_RESERVED_NODES 256
- /*
- * map address of tree root to tree
- */
- struct mapping_node {
- struct {
- struct rb_node rb_node;
- u64 bytenr;
- }; /* Use rb_simle_node for search/insert */
- void *data;
- };
- struct mapping_tree {
- struct rb_root rb_root;
- spinlock_t lock;
- };
- /*
- * present a tree block to process
- */
- struct tree_block {
- struct {
- struct rb_node rb_node;
- u64 bytenr;
- }; /* Use rb_simple_node for search/insert */
- struct btrfs_key key;
- unsigned int level:8;
- unsigned int key_ready:1;
- };
- #define MAX_EXTENTS 128
- struct file_extent_cluster {
- u64 start;
- u64 end;
- u64 boundary[MAX_EXTENTS];
- unsigned int nr;
- };
- struct reloc_control {
- /* block group to relocate */
- struct btrfs_block_group *block_group;
- /* extent tree */
- struct btrfs_root *extent_root;
- /* inode for moving data */
- struct inode *data_inode;
- struct btrfs_block_rsv *block_rsv;
- struct btrfs_backref_cache backref_cache;
- struct file_extent_cluster cluster;
- /* tree blocks have been processed */
- struct extent_io_tree processed_blocks;
- /* map start of tree root to corresponding reloc tree */
- struct mapping_tree reloc_root_tree;
- /* list of reloc trees */
- struct list_head reloc_roots;
- /* list of subvolume trees that get relocated */
- struct list_head dirty_subvol_roots;
- /* size of metadata reservation for merging reloc trees */
- u64 merging_rsv_size;
- /* size of relocated tree nodes */
- u64 nodes_relocated;
- /* reserved size for block group relocation*/
- u64 reserved_bytes;
- u64 search_start;
- u64 extents_found;
- unsigned int stage:8;
- unsigned int create_reloc_tree:1;
- unsigned int merge_reloc_tree:1;
- unsigned int found_file_extent:1;
- };
- /* stages of data relocation */
- #define MOVE_DATA_EXTENTS 0
- #define UPDATE_DATA_PTRS 1
- static void mark_block_processed(struct reloc_control *rc,
- struct btrfs_backref_node *node)
- {
- u32 blocksize;
- if (node->level == 0 ||
- in_range(node->bytenr, rc->block_group->start,
- rc->block_group->length)) {
- blocksize = rc->extent_root->fs_info->nodesize;
- set_extent_bits(&rc->processed_blocks, node->bytenr,
- node->bytenr + blocksize - 1, EXTENT_DIRTY);
- }
- node->processed = 1;
- }
- static void mapping_tree_init(struct mapping_tree *tree)
- {
- tree->rb_root = RB_ROOT;
- spin_lock_init(&tree->lock);
- }
- /*
- * walk up backref nodes until reach node presents tree root
- */
- static struct btrfs_backref_node *walk_up_backref(
- struct btrfs_backref_node *node,
- struct btrfs_backref_edge *edges[], int *index)
- {
- struct btrfs_backref_edge *edge;
- int idx = *index;
- while (!list_empty(&node->upper)) {
- edge = list_entry(node->upper.next,
- struct btrfs_backref_edge, list[LOWER]);
- edges[idx++] = edge;
- node = edge->node[UPPER];
- }
- BUG_ON(node->detached);
- *index = idx;
- return node;
- }
- /*
- * walk down backref nodes to find start of next reference path
- */
- static struct btrfs_backref_node *walk_down_backref(
- struct btrfs_backref_edge *edges[], int *index)
- {
- struct btrfs_backref_edge *edge;
- struct btrfs_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 btrfs_backref_edge, list[LOWER]);
- edges[idx - 1] = edge;
- *index = idx;
- return edge->node[UPPER];
- }
- *index = 0;
- return NULL;
- }
- static void update_backref_node(struct btrfs_backref_cache *cache,
- struct btrfs_backref_node *node, u64 bytenr)
- {
- struct rb_node *rb_node;
- rb_erase(&node->rb_node, &cache->rb_root);
- node->bytenr = bytenr;
- rb_node = rb_simple_insert(&cache->rb_root, node->bytenr, &node->rb_node);
- if (rb_node)
- btrfs_backref_panic(cache->fs_info, bytenr, -EEXIST);
- }
- /*
- * update backref cache after a transaction commit
- */
- static int update_backref_cache(struct btrfs_trans_handle *trans,
- struct btrfs_backref_cache *cache)
- {
- struct btrfs_backref_node *node;
- int level = 0;
- if (cache->last_trans == 0) {
- cache->last_trans = trans->transid;
- return 0;
- }
- if (cache->last_trans == trans->transid)
- return 0;
- /*
- * detached nodes are used to avoid unnecessary backref
- * lookup. transaction commit changes the extent tree.
- * so the detached nodes are no longer useful.
- */
- while (!list_empty(&cache->detached)) {
- node = list_entry(cache->detached.next,
- struct btrfs_backref_node, list);
- btrfs_backref_cleanup_node(cache, node);
- }
- while (!list_empty(&cache->changed)) {
- node = list_entry(cache->changed.next,
- struct btrfs_backref_node, list);
- list_del_init(&node->list);
- BUG_ON(node->pending);
- update_backref_node(cache, node, node->new_bytenr);
- }
- /*
- * some nodes can be left in the pending list if there were
- * errors during processing the pending nodes.
- */
- for (level = 0; level < BTRFS_MAX_LEVEL; level++) {
- list_for_each_entry(node, &cache->pending[level], list) {
- BUG_ON(!node->pending);
- if (node->bytenr == node->new_bytenr)
- continue;
- update_backref_node(cache, node, node->new_bytenr);
- }
- }
- cache->last_trans = 0;
- return 1;
- }
- static bool reloc_root_is_dead(struct btrfs_root *root)
- {
- /*
- * Pair with set_bit/clear_bit in clean_dirty_subvols and
- * btrfs_update_reloc_root. We need to see the updated bit before
- * trying to access reloc_root
- */
- smp_rmb();
- if (test_bit(BTRFS_ROOT_DEAD_RELOC_TREE, &root->state))
- return true;
- return false;
- }
- /*
- * Check if this subvolume tree has valid reloc tree.
- *
- * Reloc tree after swap is considered dead, thus not considered as valid.
- * This is enough for most callers, as they don't distinguish dead reloc root
- * from no reloc root. But btrfs_should_ignore_reloc_root() below is a
- * special case.
- */
- static bool have_reloc_root(struct btrfs_root *root)
- {
- if (reloc_root_is_dead(root))
- return false;
- if (!root->reloc_root)
- return false;
- return true;
- }
- int btrfs_should_ignore_reloc_root(struct btrfs_root *root)
- {
- struct btrfs_root *reloc_root;
- if (!test_bit(BTRFS_ROOT_SHAREABLE, &root->state))
- return 0;
- /* This root has been merged with its reloc tree, we can ignore it */
- if (reloc_root_is_dead(root))
- return 1;
- reloc_root = root->reloc_root;
- if (!reloc_root)
- return 0;
- if (btrfs_header_generation(reloc_root->commit_root) ==
- root->fs_info->running_transaction->transid)
- return 0;
- /*
- * if there is reloc tree and it was created in previous
- * transaction backref lookup can find the reloc tree,
- * so backref node for the fs tree root is useless for
- * relocation.
- */
- return 1;
- }
- /*
- * find reloc tree by address of tree root
- */
- struct btrfs_root *find_reloc_root(struct btrfs_fs_info *fs_info, u64 bytenr)
- {
- struct reloc_control *rc = fs_info->reloc_ctl;
- struct rb_node *rb_node;
- struct mapping_node *node;
- struct btrfs_root *root = NULL;
- ASSERT(rc);
- spin_lock(&rc->reloc_root_tree.lock);
- rb_node = rb_simple_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 btrfs_grab_root(root);
- }
- /*
- * For useless nodes, do two major clean ups:
- *
- * - Cleanup the children edges and nodes
- * If child node is also orphan (no parent) during cleanup, then the child
- * node will also be cleaned up.
- *
- * - Freeing up leaves (level 0), keeps nodes detached
- * For nodes, the node is still cached as "detached"
- *
- * Return false if @node is not in the @useless_nodes list.
- * Return true if @node is in the @useless_nodes list.
- */
- static bool handle_useless_nodes(struct reloc_control *rc,
- struct btrfs_backref_node *node)
- {
- struct btrfs_backref_cache *cache = &rc->backref_cache;
- struct list_head *useless_node = &cache->useless_node;
- bool ret = false;
- while (!list_empty(useless_node)) {
- struct btrfs_backref_node *cur;
- cur = list_first_entry(useless_node, struct btrfs_backref_node,
- list);
- list_del_init(&cur->list);
- /* Only tree root nodes can be added to @useless_nodes */
- ASSERT(list_empty(&cur->upper));
- if (cur == node)
- ret = true;
- /* The node is the lowest node */
- if (cur->lowest) {
- list_del_init(&cur->lower);
- cur->lowest = 0;
- }
- /* Cleanup the lower edges */
- while (!list_empty(&cur->lower)) {
- struct btrfs_backref_edge *edge;
- struct btrfs_backref_node *lower;
- edge = list_entry(cur->lower.next,
- struct btrfs_backref_edge, list[UPPER]);
- list_del(&edge->list[UPPER]);
- list_del(&edge->list[LOWER]);
- lower = edge->node[LOWER];
- btrfs_backref_free_edge(cache, edge);
- /* Child node is also orphan, queue for cleanup */
- if (list_empty(&lower->upper))
- list_add(&lower->list, useless_node);
- }
- /* Mark this block processed for relocation */
- mark_block_processed(rc, cur);
- /*
- * Backref nodes for tree leaves are deleted from the cache.
- * Backref nodes for upper level tree blocks are left in the
- * cache to avoid unnecessary backref lookup.
- */
- if (cur->level > 0) {
- list_add(&cur->list, &cache->detached);
- cur->detached = 1;
- } else {
- rb_erase(&cur->rb_node, &cache->rb_root);
- btrfs_backref_free_node(cache, cur);
- }
- }
- return ret;
- }
- /*
- * Build backref tree for a given tree block. Root of the backref tree
- * corresponds the tree block, leaves of the backref tree correspond roots of
- * b-trees that reference the tree block.
- *
- * The basic idea of this function is check backrefs of a given block to find
- * upper level blocks that reference the block, and then check backrefs of
- * these upper level blocks recursively. The recursion stops when tree root is
- * reached or backrefs for the block is cached.
- *
- * NOTE: if we find that backrefs for a block are cached, we know backrefs for
- * all upper level blocks that directly/indirectly reference the block are also
- * cached.
- */
- static noinline_for_stack struct btrfs_backref_node *build_backref_tree(
- struct reloc_control *rc, struct btrfs_key *node_key,
- int level, u64 bytenr)
- {
- struct btrfs_backref_iter *iter;
- struct btrfs_backref_cache *cache = &rc->backref_cache;
- /* For searching parent of TREE_BLOCK_REF */
- struct btrfs_path *path;
- struct btrfs_backref_node *cur;
- struct btrfs_backref_node *node = NULL;
- struct btrfs_backref_edge *edge;
- int ret;
- int err = 0;
- iter = btrfs_backref_iter_alloc(rc->extent_root->fs_info, GFP_NOFS);
- if (!iter)
- return ERR_PTR(-ENOMEM);
- path = btrfs_alloc_path();
- if (!path) {
- err = -ENOMEM;
- goto out;
- }
- node = btrfs_backref_alloc_node(cache, bytenr, level);
- if (!node) {
- err = -ENOMEM;
- goto out;
- }
- node->lowest = 1;
- cur = node;
- /* Breadth-first search to build backref cache */
- do {
- ret = btrfs_backref_add_tree_node(cache, path, iter, node_key,
- cur);
- if (ret < 0) {
- err = ret;
- goto out;
- }
- edge = list_first_entry_or_null(&cache->pending_edge,
- struct btrfs_backref_edge, list[UPPER]);
- /*
- * The pending list isn't empty, take the first block to
- * process
- */
- if (edge) {
- list_del_init(&edge->list[UPPER]);
- cur = edge->node[UPPER];
- }
- } while (edge);
- /* Finish the upper linkage of newly added edges/nodes */
- ret = btrfs_backref_finish_upper_links(cache, node);
- if (ret < 0) {
- err = ret;
- goto out;
- }
- if (handle_useless_nodes(rc, node))
- node = NULL;
- out:
- btrfs_backref_iter_free(iter);
- btrfs_free_path(path);
- if (err) {
- btrfs_backref_error_cleanup(cache, node);
- return ERR_PTR(err);
- }
- ASSERT(!node || !node->detached);
- ASSERT(list_empty(&cache->useless_node) &&
- list_empty(&cache->pending_edge));
- return node;
- }
- /*
- * helper to add backref node for the newly created snapshot.
- * the backref node is created by cloning backref node that
- * corresponds to root of source tree
- */
- static int clone_backref_node(struct btrfs_trans_handle *trans,
- struct reloc_control *rc,
- struct btrfs_root *src,
- struct btrfs_root *dest)
- {
- struct btrfs_root *reloc_root = src->reloc_root;
- struct btrfs_backref_cache *cache = &rc->backref_cache;
- struct btrfs_backref_node *node = NULL;
- struct btrfs_backref_node *new_node;
- struct btrfs_backref_edge *edge;
- struct btrfs_backref_edge *new_edge;
- struct rb_node *rb_node;
- if (cache->last_trans > 0)
- update_backref_cache(trans, cache);
- rb_node = rb_simple_search(&cache->rb_root, src->commit_root->start);
- if (rb_node) {
- node = rb_entry(rb_node, struct btrfs_backref_node, rb_node);
- if (node->detached)
- node = NULL;
- else
- BUG_ON(node->new_bytenr != reloc_root->node->start);
- }
- if (!node) {
- rb_node = rb_simple_search(&cache->rb_root,
- reloc_root->commit_root->start);
- if (rb_node) {
- node = rb_entry(rb_node, struct btrfs_backref_node,
- rb_node);
- BUG_ON(node->detached);
- }
- }
- if (!node)
- return 0;
- new_node = btrfs_backref_alloc_node(cache, dest->node->start,
- node->level);
- if (!new_node)
- return -ENOMEM;
- new_node->lowest = node->lowest;
- new_node->checked = 1;
- new_node->root = btrfs_grab_root(dest);
- ASSERT(new_node->root);
- if (!node->lowest) {
- list_for_each_entry(edge, &node->lower, list[UPPER]) {
- new_edge = btrfs_backref_alloc_edge(cache);
- if (!new_edge)
- goto fail;
- btrfs_backref_link_edge(new_edge, edge->node[LOWER],
- new_node, LINK_UPPER);
- }
- } else {
- list_add_tail(&new_node->lower, &cache->leaves);
- }
- rb_node = rb_simple_insert(&cache->rb_root, new_node->bytenr,
- &new_node->rb_node);
- if (rb_node)
- btrfs_backref_panic(trans->fs_info, new_node->bytenr, -EEXIST);
- if (!new_node->lowest) {
- list_for_each_entry(new_edge, &new_node->lower, list[UPPER]) {
- list_add_tail(&new_edge->list[LOWER],
- &new_edge->node[LOWER]->upper);
- }
- }
- return 0;
- fail:
- while (!list_empty(&new_node->lower)) {
- new_edge = list_entry(new_node->lower.next,
- struct btrfs_backref_edge, list[UPPER]);
- list_del(&new_edge->list[UPPER]);
- btrfs_backref_free_edge(cache, new_edge);
- }
- btrfs_backref_free_node(cache, new_node);
- return -ENOMEM;
- }
- /*
- * helper to add 'address of tree root -> reloc tree' mapping
- */
- static int __must_check __add_reloc_root(struct btrfs_root *root)
- {
- struct btrfs_fs_info *fs_info = root->fs_info;
- struct rb_node *rb_node;
- struct mapping_node *node;
- struct reloc_control *rc = fs_info->reloc_ctl;
- node = kmalloc(sizeof(*node), GFP_NOFS);
- if (!node)
- return -ENOMEM;
- node->bytenr = root->commit_root->start;
- node->data = root;
- spin_lock(&rc->reloc_root_tree.lock);
- rb_node = rb_simple_insert(&rc->reloc_root_tree.rb_root,
- node->bytenr, &node->rb_node);
- spin_unlock(&rc->reloc_root_tree.lock);
- if (rb_node) {
- btrfs_panic(fs_info, -EEXIST,
- "Duplicate root found for start=%llu while inserting into relocation tree",
- node->bytenr);
- }
- list_add_tail(&root->root_list, &rc->reloc_roots);
- return 0;
- }
- /*
- * helper to delete the 'address of tree root -> reloc tree'
- * mapping
- */
- static void __del_reloc_root(struct btrfs_root *root)
- {
- struct btrfs_fs_info *fs_info = root->fs_info;
- struct rb_node *rb_node;
- struct mapping_node *node = NULL;
- struct reloc_control *rc = fs_info->reloc_ctl;
- bool put_ref = false;
- if (rc && root->node) {
- spin_lock(&rc->reloc_root_tree.lock);
- rb_node = rb_simple_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);
- RB_CLEAR_NODE(&node->rb_node);
- }
- spin_unlock(&rc->reloc_root_tree.lock);
- ASSERT(!node || (struct btrfs_root *)node->data == root);
- }
- /*
- * We only put the reloc root here if it's on the list. There's a lot
- * of places where the pattern is to splice the rc->reloc_roots, process
- * the reloc roots, and then add the reloc root back onto
- * rc->reloc_roots. If we call __del_reloc_root while it's off of the
- * list we don't want the reference being dropped, because the guy
- * messing with the list is in charge of the reference.
- */
- spin_lock(&fs_info->trans_lock);
- if (!list_empty(&root->root_list)) {
- put_ref = true;
- list_del_init(&root->root_list);
- }
- spin_unlock(&fs_info->trans_lock);
- if (put_ref)
- btrfs_put_root(root);
- kfree(node);
- }
- /*
- * helper to update the 'address of tree root -> reloc tree'
- * mapping
- */
- static int __update_reloc_root(struct btrfs_root *root)
- {
- struct btrfs_fs_info *fs_info = root->fs_info;
- struct rb_node *rb_node;
- struct mapping_node *node = NULL;
- struct reloc_control *rc = fs_info->reloc_ctl;
- spin_lock(&rc->reloc_root_tree.lock);
- rb_node = rb_simple_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);
- if (!node)
- return 0;
- BUG_ON((struct btrfs_root *)node->data != root);
- spin_lock(&rc->reloc_root_tree.lock);
- node->bytenr = root->node->start;
- rb_node = rb_simple_insert(&rc->reloc_root_tree.rb_root,
- node->bytenr, &node->rb_node);
- spin_unlock(&rc->reloc_root_tree.lock);
- if (rb_node)
- btrfs_backref_panic(fs_info, node->bytenr, -EEXIST);
- return 0;
- }
- static struct btrfs_root *create_reloc_root(struct btrfs_trans_handle *trans,
- struct btrfs_root *root, u64 objectid)
- {
- struct btrfs_fs_info *fs_info = root->fs_info;
- struct btrfs_root *reloc_root;
- struct extent_buffer *eb;
- struct btrfs_root_item *root_item;
- struct btrfs_key root_key;
- int ret = 0;
- bool must_abort = false;
- root_item = kmalloc(sizeof(*root_item), GFP_NOFS);
- if (!root_item)
- return ERR_PTR(-ENOMEM);
- root_key.objectid = BTRFS_TREE_RELOC_OBJECTID;
- root_key.type = BTRFS_ROOT_ITEM_KEY;
- root_key.offset = objectid;
- if (root->root_key.objectid == objectid) {
- u64 commit_root_gen;
- /* called by btrfs_init_reloc_root */
- ret = btrfs_copy_root(trans, root, root->commit_root, &eb,
- BTRFS_TREE_RELOC_OBJECTID);
- if (ret)
- goto fail;
- /*
- * Set the last_snapshot field to the generation of the commit
- * root - like this ctree.c:btrfs_block_can_be_shared() behaves
- * correctly (returns true) when the relocation root is created
- * either inside the critical section of a transaction commit
- * (through transaction.c:qgroup_account_snapshot()) and when
- * it's created before the transaction commit is started.
- */
- commit_root_gen = btrfs_header_generation(root->commit_root);
- btrfs_set_root_last_snapshot(&root->root_item, commit_root_gen);
- } else {
- /*
- * called by btrfs_reloc_post_snapshot_hook.
- * the source tree is a reloc tree, all tree blocks
- * modified after it was created have RELOC flag
- * set in their headers. so it's OK to not update
- * the 'last_snapshot'.
- */
- ret = btrfs_copy_root(trans, root, root->node, &eb,
- BTRFS_TREE_RELOC_OBJECTID);
- if (ret)
- goto fail;
- }
- /*
- * We have changed references at this point, we must abort the
- * transaction if anything fails.
- */
- must_abort = true;
- memcpy(root_item, &root->root_item, sizeof(*root_item));
- btrfs_set_root_bytenr(root_item, eb->start);
- btrfs_set_root_level(root_item, btrfs_header_level(eb));
- btrfs_set_root_generation(root_item, trans->transid);
- if (root->root_key.objectid == objectid) {
- btrfs_set_root_refs(root_item, 0);
- memset(&root_item->drop_progress, 0,
- sizeof(struct btrfs_disk_key));
- root_item->drop_level = 0;
- }
- btrfs_tree_unlock(eb);
- free_extent_buffer(eb);
- ret = btrfs_insert_root(trans, fs_info->tree_root,
- &root_key, root_item);
- if (ret)
- goto fail;
- kfree(root_item);
- reloc_root = btrfs_read_tree_root(fs_info->tree_root, &root_key);
- if (IS_ERR(reloc_root)) {
- ret = PTR_ERR(reloc_root);
- goto abort;
- }
- set_bit(BTRFS_ROOT_SHAREABLE, &reloc_root->state);
- reloc_root->last_trans = trans->transid;
- return reloc_root;
- fail:
- kfree(root_item);
- abort:
- if (must_abort)
- btrfs_abort_transaction(trans, ret);
- return ERR_PTR(ret);
- }
- /*
- * create reloc tree for a given fs tree. reloc tree is just a
- * snapshot of the fs tree with special root objectid.
- *
- * The reloc_root comes out of here with two references, one for
- * root->reloc_root, and another for being on the rc->reloc_roots list.
- */
- int btrfs_init_reloc_root(struct btrfs_trans_handle *trans,
- struct btrfs_root *root)
- {
- struct btrfs_fs_info *fs_info = root->fs_info;
- struct btrfs_root *reloc_root;
- struct reloc_control *rc = fs_info->reloc_ctl;
- struct btrfs_block_rsv *rsv;
- int clear_rsv = 0;
- int ret;
- if (!rc)
- return 0;
- /*
- * The subvolume has reloc tree but the swap is finished, no need to
- * create/update the dead reloc tree
- */
- if (reloc_root_is_dead(root))
- return 0;
- /*
- * This is subtle but important. We do not do
- * record_root_in_transaction for reloc roots, instead we record their
- * corresponding fs root, and then here we update the last trans for the
- * reloc root. This means that we have to do this for the entire life
- * of the reloc root, regardless of which stage of the relocation we are
- * in.
- */
- if (root->reloc_root) {
- reloc_root = root->reloc_root;
- reloc_root->last_trans = trans->transid;
- return 0;
- }
- /*
- * We are merging reloc roots, we do not need new reloc trees. Also
- * reloc trees never need their own reloc tree.
- */
- if (!rc->create_reloc_tree ||
- root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID)
- return 0;
- if (!trans->reloc_reserved) {
- rsv = trans->block_rsv;
- trans->block_rsv = rc->block_rsv;
- clear_rsv = 1;
- }
- reloc_root = create_reloc_root(trans, root, root->root_key.objectid);
- if (clear_rsv)
- trans->block_rsv = rsv;
- ret = __add_reloc_root(reloc_root);
- BUG_ON(ret < 0);
- root->reloc_root = btrfs_grab_root(reloc_root);
- return 0;
- }
- /*
- * update root item of reloc tree
- */
- int btrfs_update_reloc_root(struct btrfs_trans_handle *trans,
- struct btrfs_root *root)
- {
- struct btrfs_fs_info *fs_info = root->fs_info;
- struct btrfs_root *reloc_root;
- struct btrfs_root_item *root_item;
- int ret;
- if (!have_reloc_root(root))
- return 0;
- reloc_root = root->reloc_root;
- root_item = &reloc_root->root_item;
- /*
- * We are probably ok here, but __del_reloc_root() will drop its ref of
- * the root. We have the ref for root->reloc_root, but just in case
- * hold it while we update the reloc root.
- */
- btrfs_grab_root(reloc_root);
- /* root->reloc_root will stay until current relocation finished */
- if (fs_info->reloc_ctl->merge_reloc_tree &&
- btrfs_root_refs(root_item) == 0) {
- set_bit(BTRFS_ROOT_DEAD_RELOC_TREE, &root->state);
- /*
- * Mark the tree as dead before we change reloc_root so
- * have_reloc_root will not touch it from now on.
- */
- smp_wmb();
- __del_reloc_root(reloc_root);
- }
- if (reloc_root->commit_root != reloc_root->node) {
- __update_reloc_root(reloc_root);
- btrfs_set_root_node(root_item, reloc_root->node);
- free_extent_buffer(reloc_root->commit_root);
- reloc_root->commit_root = btrfs_root_node(reloc_root);
- }
- ret = btrfs_update_root(trans, fs_info->tree_root,
- &reloc_root->root_key, root_item);
- btrfs_put_root(reloc_root);
- return ret;
- }
- /*
- * helper to find first cached inode with inode number >= objectid
- * in a subvolume
- */
- static struct inode *find_next_inode(struct btrfs_root *root, u64 objectid)
- {
- struct rb_node *node;
- struct rb_node *prev;
- struct btrfs_inode *entry;
- struct inode *inode;
- spin_lock(&root->inode_lock);
- again:
- node = root->inode_tree.rb_node;
- prev = NULL;
- while (node) {
- prev = node;
- entry = rb_entry(node, struct btrfs_inode, rb_node);
- if (objectid < btrfs_ino(entry))
- node = node->rb_left;
- else if (objectid > btrfs_ino(entry))
- node = node->rb_right;
- else
- break;
- }
- if (!node) {
- while (prev) {
- entry = rb_entry(prev, struct btrfs_inode, rb_node);
- if (objectid <= btrfs_ino(entry)) {
- node = prev;
- break;
- }
- prev = rb_next(prev);
- }
- }
- while (node) {
- entry = rb_entry(node, struct btrfs_inode, rb_node);
- inode = igrab(&entry->vfs_inode);
- if (inode) {
- spin_unlock(&root->inode_lock);
- return inode;
- }
- objectid = btrfs_ino(entry) + 1;
- if (cond_resched_lock(&root->inode_lock))
- goto again;
- node = rb_next(node);
- }
- spin_unlock(&root->inode_lock);
- return NULL;
- }
- /*
- * get new location of data
- */
- static int get_new_location(struct inode *reloc_inode, u64 *new_bytenr,
- u64 bytenr, u64 num_bytes)
- {
- struct btrfs_root *root = BTRFS_I(reloc_inode)->root;
- struct btrfs_path *path;
- struct btrfs_file_extent_item *fi;
- struct extent_buffer *leaf;
- int ret;
- path = btrfs_alloc_path();
- if (!path)
- return -ENOMEM;
- bytenr -= BTRFS_I(reloc_inode)->index_cnt;
- ret = btrfs_lookup_file_extent(NULL, root, path,
- btrfs_ino(BTRFS_I(reloc_inode)), bytenr, 0);
- if (ret < 0)
- goto out;
- if (ret > 0) {
- ret = -ENOENT;
- goto out;
- }
- leaf = path->nodes[0];
- fi = btrfs_item_ptr(leaf, path->slots[0],
- struct btrfs_file_extent_item);
- BUG_ON(btrfs_file_extent_offset(leaf, fi) ||
- btrfs_file_extent_compression(leaf, fi) ||
- btrfs_file_extent_encryption(leaf, fi) ||
- btrfs_file_extent_other_encoding(leaf, fi));
- if (num_bytes != btrfs_file_extent_disk_num_bytes(leaf, fi)) {
- ret = -EINVAL;
- goto out;
- }
- *new_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
- ret = 0;
- out:
- btrfs_free_path(path);
- return ret;
- }
- /*
- * update file extent items in the tree leaf to point to
- * the new locations.
- */
- static noinline_for_stack
- int replace_file_extents(struct btrfs_trans_handle *trans,
- struct reloc_control *rc,
- struct btrfs_root *root,
- struct extent_buffer *leaf)
- {
- struct btrfs_fs_info *fs_info = root->fs_info;
- struct btrfs_key key;
- struct btrfs_file_extent_item *fi;
- struct inode *inode = NULL;
- u64 parent;
- u64 bytenr;
- u64 new_bytenr = 0;
- u64 num_bytes;
- u64 end;
- u32 nritems;
- u32 i;
- int ret = 0;
- int first = 1;
- int dirty = 0;
- if (rc->stage != UPDATE_DATA_PTRS)
- return 0;
- /* reloc trees always use full backref */
- if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID)
- parent = leaf->start;
- else
- parent = 0;
- nritems = btrfs_header_nritems(leaf);
- for (i = 0; i < nritems; i++) {
- struct btrfs_ref ref = { 0 };
- 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_range(bytenr, rc->block_group->start,
- rc->block_group->length))
- continue;
- /*
- * if we are modifying block in fs tree, wait for readpage
- * to complete and drop the extent cache
- */
- if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
- if (first) {
- inode = find_next_inode(root, key.objectid);
- first = 0;
- } else if (inode && btrfs_ino(BTRFS_I(inode)) < key.objectid) {
- btrfs_add_delayed_iput(inode);
- inode = find_next_inode(root, key.objectid);
- }
- if (inode && btrfs_ino(BTRFS_I(inode)) == key.objectid) {
- end = key.offset +
- btrfs_file_extent_num_bytes(leaf, fi);
- WARN_ON(!IS_ALIGNED(key.offset,
- fs_info->sectorsize));
- WARN_ON(!IS_ALIGNED(end, fs_info->sectorsize));
- end--;
- ret = try_lock_extent(&BTRFS_I(inode)->io_tree,
- key.offset, end);
- if (!ret)
- continue;
- btrfs_drop_extent_cache(BTRFS_I(inode),
- key.offset, end, 1);
- unlock_extent(&BTRFS_I(inode)->io_tree,
- key.offset, end);
- }
- }
- ret = get_new_location(rc->data_inode, &new_bytenr,
- bytenr, num_bytes);
- if (ret) {
- /*
- * Don't have to abort since we've not changed anything
- * in the file extent yet.
- */
- break;
- }
- btrfs_set_file_extent_disk_bytenr(leaf, fi, new_bytenr);
- dirty = 1;
- key.offset -= btrfs_file_extent_offset(leaf, fi);
- btrfs_init_generic_ref(&ref, BTRFS_ADD_DELAYED_REF, new_bytenr,
- num_bytes, parent);
- ref.real_root = root->root_key.objectid;
- btrfs_init_data_ref(&ref, btrfs_header_owner(leaf),
- key.objectid, key.offset);
- ret = btrfs_inc_extent_ref(trans, &ref);
- if (ret) {
- btrfs_abort_transaction(trans, ret);
- break;
- }
- btrfs_init_generic_ref(&ref, BTRFS_DROP_DELAYED_REF, bytenr,
- num_bytes, parent);
- ref.real_root = root->root_key.objectid;
- btrfs_init_data_ref(&ref, btrfs_header_owner(leaf),
- key.objectid, key.offset);
- ret = btrfs_free_extent(trans, &ref);
- if (ret) {
- btrfs_abort_transaction(trans, ret);
- break;
- }
- }
- if (dirty)
- btrfs_mark_buffer_dirty(leaf);
- if (inode)
- btrfs_add_delayed_iput(inode);
- return ret;
- }
- static noinline_for_stack
- int memcmp_node_keys(struct extent_buffer *eb, int slot,
- struct btrfs_path *path, int level)
- {
- struct btrfs_disk_key key1;
- struct btrfs_disk_key key2;
- btrfs_node_key(eb, &key1, slot);
- btrfs_node_key(path->nodes[level], &key2, path->slots[level]);
- return memcmp(&key1, &key2, sizeof(key1));
- }
- /*
- * try to replace tree blocks in fs tree with the new blocks
- * in reloc tree. tree blocks haven't been modified since the
- * reloc tree was create can be replaced.
- *
- * if a block was replaced, level of the block + 1 is returned.
- * if no block got replaced, 0 is returned. if there are other
- * errors, a negative error number is returned.
- */
- static noinline_for_stack
- int replace_path(struct btrfs_trans_handle *trans, struct reloc_control *rc,
- struct btrfs_root *dest, struct btrfs_root *src,
- struct btrfs_path *path, struct btrfs_key *next_key,
- int lowest_level, int max_level)
- {
- struct btrfs_fs_info *fs_info = dest->fs_info;
- struct extent_buffer *eb;
- struct extent_buffer *parent;
- struct btrfs_ref ref = { 0 };
- struct btrfs_key key;
- u64 old_bytenr;
- u64 new_bytenr;
- u64 old_ptr_gen;
- u64 new_ptr_gen;
- u64 last_snapshot;
- u32 blocksize;
- int cow = 0;
- int level;
- int ret;
- int slot;
- ASSERT(src->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID);
- ASSERT(dest->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
- last_snapshot = btrfs_root_last_snapshot(&src->root_item);
- again:
- slot = path->slots[lowest_level];
- btrfs_node_key_to_cpu(path->nodes[lowest_level], &key, slot);
- eb = btrfs_lock_root_node(dest);
- btrfs_set_lock_blocking_write(eb);
- level = btrfs_header_level(eb);
- if (level < lowest_level) {
- btrfs_tree_unlock(eb);
- free_extent_buffer(eb);
- return 0;
- }
- if (cow) {
- ret = btrfs_cow_block(trans, dest, eb, NULL, 0, &eb,
- BTRFS_NESTING_COW);
- BUG_ON(ret);
- }
- btrfs_set_lock_blocking_write(eb);
- if (next_key) {
- next_key->objectid = (u64)-1;
- next_key->type = (u8)-1;
- next_key->offset = (u64)-1;
- }
- parent = eb;
- while (1) {
- struct btrfs_key first_key;
- level = btrfs_header_level(parent);
- ASSERT(level >= lowest_level);
- ret = btrfs_bin_search(parent, &key, &slot);
- if (ret < 0)
- break;
- if (ret && slot > 0)
- slot--;
- if (next_key && slot + 1 < btrfs_header_nritems(parent))
- btrfs_node_key_to_cpu(parent, next_key, slot + 1);
- old_bytenr = btrfs_node_blockptr(parent, slot);
- blocksize = fs_info->nodesize;
- old_ptr_gen = btrfs_node_ptr_generation(parent, slot);
- btrfs_node_key_to_cpu(parent, &first_key, slot);
- if (level <= max_level) {
- eb = path->nodes[level];
- new_bytenr = btrfs_node_blockptr(eb,
- path->slots[level]);
- new_ptr_gen = btrfs_node_ptr_generation(eb,
- path->slots[level]);
- } else {
- new_bytenr = 0;
- new_ptr_gen = 0;
- }
- if (WARN_ON(new_bytenr > 0 && new_bytenr == old_bytenr)) {
- ret = level;
- break;
- }
- if (new_bytenr == 0 || old_ptr_gen > last_snapshot ||
- memcmp_node_keys(parent, slot, path, level)) {
- if (level <= lowest_level) {
- ret = 0;
- break;
- }
- eb = read_tree_block(fs_info, old_bytenr, old_ptr_gen,
- level - 1, &first_key);
- if (IS_ERR(eb)) {
- ret = PTR_ERR(eb);
- break;
- } else if (!extent_buffer_uptodate(eb)) {
- ret = -EIO;
- free_extent_buffer(eb);
- break;
- }
- btrfs_tree_lock(eb);
- if (cow) {
- ret = btrfs_cow_block(trans, dest, eb, parent,
- slot, &eb,
- BTRFS_NESTING_COW);
- BUG_ON(ret);
- }
- btrfs_set_lock_blocking_write(eb);
- btrfs_tree_unlock(parent);
- free_extent_buffer(parent);
- parent = eb;
- continue;
- }
- if (!cow) {
- btrfs_tree_unlock(parent);
- free_extent_buffer(parent);
- cow = 1;
- goto again;
- }
- btrfs_node_key_to_cpu(path->nodes[level], &key,
- path->slots[level]);
- btrfs_release_path(path);
- path->lowest_level = level;
- ret = btrfs_search_slot(trans, src, &key, path, 0, 1);
- path->lowest_level = 0;
- BUG_ON(ret);
- /*
- * Info qgroup to trace both subtrees.
- *
- * We must trace both trees.
- * 1) Tree reloc subtree
- * If not traced, we will leak data numbers
- * 2) Fs subtree
- * If not traced, we will double count old data
- *
- * We don't scan the subtree right now, but only record
- * the swapped tree blocks.
- * The real subtree rescan is delayed until we have new
- * CoW on the subtree root node before transaction commit.
- */
- ret = btrfs_qgroup_add_swapped_blocks(trans, dest,
- rc->block_group, parent, slot,
- path->nodes[level], path->slots[level],
- last_snapshot);
- if (ret < 0)
- break;
- /*
- * swap blocks in fs tree and reloc tree.
- */
- btrfs_set_node_blockptr(parent, slot, new_bytenr);
- btrfs_set_node_ptr_generation(parent, slot, new_ptr_gen);
- btrfs_mark_buffer_dirty(parent);
- btrfs_set_node_blockptr(path->nodes[level],
- path->slots[level], old_bytenr);
- btrfs_set_node_ptr_generation(path->nodes[level],
- path->slots[level], old_ptr_gen);
- btrfs_mark_buffer_dirty(path->nodes[level]);
- btrfs_init_generic_ref(&ref, BTRFS_ADD_DELAYED_REF, old_bytenr,
- blocksize, path->nodes[level]->start);
- ref.skip_qgroup = true;
- btrfs_init_tree_ref(&ref, level - 1, src->root_key.objectid);
- ret = btrfs_inc_extent_ref(trans, &ref);
- BUG_ON(ret);
- btrfs_init_generic_ref(&ref, BTRFS_ADD_DELAYED_REF, new_bytenr,
- blocksize, 0);
- ref.skip_qgroup = true;
- btrfs_init_tree_ref(&ref, level - 1, dest->root_key.objectid);
- ret = btrfs_inc_extent_ref(trans, &ref);
- BUG_ON(ret);
- btrfs_init_generic_ref(&ref, BTRFS_DROP_DELAYED_REF, new_bytenr,
- blocksize, path->nodes[level]->start);
- btrfs_init_tree_ref(&ref, level - 1, src->root_key.objectid);
- ref.skip_qgroup = true;
- ret = btrfs_free_extent(trans, &ref);
- BUG_ON(ret);
- btrfs_init_generic_ref(&ref, BTRFS_DROP_DELAYED_REF, old_bytenr,
- blocksize, 0);
- btrfs_init_tree_ref(&ref, level - 1, dest->root_key.objectid);
- ref.skip_qgroup = true;
- ret = btrfs_free_extent(trans, &ref);
- BUG_ON(ret);
- btrfs_unlock_up_safe(path, 0);
- ret = level;
- break;
- }
- btrfs_tree_unlock(parent);
- free_extent_buffer(parent);
- return ret;
- }
- /*
- * helper to find next relocated block in reloc tree
- */
- static noinline_for_stack
- int walk_up_reloc_tree(struct btrfs_root *root, struct btrfs_path *path,
- int *level)
- {
- struct extent_buffer *eb;
- int i;
- u64 last_snapshot;
- u32 nritems;
- last_snapshot = btrfs_root_last_snapshot(&root->root_item);
- for (i = 0; i < *level; i++) {
- free_extent_buffer(path->nodes[i]);
- path->nodes[i] = NULL;
- }
- for (i = *level; i < BTRFS_MAX_LEVEL && path->nodes[i]; i++) {
- eb = path->nodes[i];
- nritems = btrfs_header_nritems(eb);
- while (path->slots[i] + 1 < nritems) {
- path->slots[i]++;
- if (btrfs_node_ptr_generation(eb, path->slots[i]) <=
- last_snapshot)
- continue;
- *level = i;
- return 0;
- }
- free_extent_buffer(path->nodes[i]);
- path->nodes[i] = NULL;
- }
- return 1;
- }
- /*
- * walk down reloc tree to find relocated block of lowest level
- */
- static noinline_for_stack
- int walk_down_reloc_tree(struct btrfs_root *root, struct btrfs_path *path,
- int *level)
- {
- struct btrfs_fs_info *fs_info = root->fs_info;
- struct extent_buffer *eb = NULL;
- int i;
- u64 bytenr;
- u64 ptr_gen = 0;
- u64 last_snapshot;
- u32 nritems;
- last_snapshot = btrfs_root_last_snapshot(&root->root_item);
- for (i = *level; i > 0; i--) {
- struct btrfs_key first_key;
- eb = path->nodes[i];
- nritems = btrfs_header_nritems(eb);
- while (path->slots[i] < nritems) {
- ptr_gen = btrfs_node_ptr_generation(eb, path->slots[i]);
- if (ptr_gen > last_snapshot)
- break;
- path->slots[i]++;
- }
- if (path->slots[i] >= nritems) {
- if (i == *level)
- break;
- *level = i + 1;
- return 0;
- }
- if (i == 1) {
- *level = i;
- return 0;
- }
- bytenr = btrfs_node_blockptr(eb, path->slots[i]);
- btrfs_node_key_to_cpu(eb, &first_key, path->slots[i]);
- eb = read_tree_block(fs_info, bytenr, ptr_gen, i - 1,
- &first_key);
- if (IS_ERR(eb)) {
- return PTR_ERR(eb);
- } else if (!extent_buffer_uptodate(eb)) {
- free_extent_buffer(eb);
- return -EIO;
- }
- BUG_ON(btrfs_header_level(eb) != i - 1);
- path->nodes[i - 1] = eb;
- path->slots[i - 1] = 0;
- }
- return 1;
- }
- /*
- * invalidate extent cache for file extents whose key in range of
- * [min_key, max_key)
- */
- static int invalidate_extent_cache(struct btrfs_root *root,
- struct btrfs_key *min_key,
- struct btrfs_key *max_key)
- {
- struct btrfs_fs_info *fs_info = root->fs_info;
- struct inode *inode = NULL;
- u64 objectid;
- u64 start, end;
- u64 ino;
- objectid = min_key->objectid;
- while (1) {
- cond_resched();
- iput(inode);
- if (objectid > max_key->objectid)
- break;
- inode = find_next_inode(root, objectid);
- if (!inode)
- break;
- ino = btrfs_ino(BTRFS_I(inode));
- if (ino > max_key->objectid) {
- iput(inode);
- break;
- }
- objectid = ino + 1;
- if (!S_ISREG(inode->i_mode))
- continue;
- if (unlikely(min_key->objectid == ino)) {
- if (min_key->type > BTRFS_EXTENT_DATA_KEY)
- continue;
- if (min_key->type < BTRFS_EXTENT_DATA_KEY)
- start = 0;
- else {
- start = min_key->offset;
- WARN_ON(!IS_ALIGNED(start, fs_info->sectorsize));
- }
- } else {
- start = 0;
- }
- if (unlikely(max_key->objectid == ino)) {
- if (max_key->type < BTRFS_EXTENT_DATA_KEY)
- continue;
- if (max_key->type > BTRFS_EXTENT_DATA_KEY) {
- end = (u64)-1;
- } else {
- if (max_key->offset == 0)
- continue;
- end = max_key->offset;
- WARN_ON(!IS_ALIGNED(end, fs_info->sectorsize));
- end--;
- }
- } else {
- end = (u64)-1;
- }
- /* the lock_extent waits for readpage to complete */
- lock_extent(&BTRFS_I(inode)->io_tree, start, end);
- btrfs_drop_extent_cache(BTRFS_I(inode), start, end, 1);
- unlock_extent(&BTRFS_I(inode)->io_tree, start, end);
- }
- return 0;
- }
- static int find_next_key(struct btrfs_path *path, int level,
- struct btrfs_key *key)
- {
- while (level < BTRFS_MAX_LEVEL) {
- if (!path->nodes[level])
- break;
- if (path->slots[level] + 1 <
- btrfs_header_nritems(path->nodes[level])) {
- btrfs_node_key_to_cpu(path->nodes[level], key,
- path->slots[level] + 1);
- return 0;
- }
- level++;
- }
- return 1;
- }
- /*
- * Insert current subvolume into reloc_control::dirty_subvol_roots
- */
- static void insert_dirty_subvol(struct btrfs_trans_handle *trans,
- struct reloc_control *rc,
- struct btrfs_root *root)
- {
- struct btrfs_root *reloc_root = root->reloc_root;
- struct btrfs_root_item *reloc_root_item;
- /* @root must be a subvolume tree root with a valid reloc tree */
- ASSERT(root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
- ASSERT(reloc_root);
- reloc_root_item = &reloc_root->root_item;
- memset(&reloc_root_item->drop_progress, 0,
- sizeof(reloc_root_item->drop_progress));
- reloc_root_item->drop_level = 0;
- btrfs_set_root_refs(reloc_root_item, 0);
- btrfs_update_reloc_root(trans, root);
- if (list_empty(&root->reloc_dirty_list)) {
- btrfs_grab_root(root);
- list_add_tail(&root->reloc_dirty_list, &rc->dirty_subvol_roots);
- }
- }
- static int clean_dirty_subvols(struct reloc_control *rc)
- {
- struct btrfs_root *root;
- struct btrfs_root *next;
- int ret = 0;
- int ret2;
- list_for_each_entry_safe(root, next, &rc->dirty_subvol_roots,
- reloc_dirty_list) {
- if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
- /* Merged subvolume, cleanup its reloc root */
- struct btrfs_root *reloc_root = root->reloc_root;
- list_del_init(&root->reloc_dirty_list);
- root->reloc_root = NULL;
- /*
- * Need barrier to ensure clear_bit() only happens after
- * root->reloc_root = NULL. Pairs with have_reloc_root.
- */
- smp_wmb();
- clear_bit(BTRFS_ROOT_DEAD_RELOC_TREE, &root->state);
- if (reloc_root) {
- /*
- * btrfs_drop_snapshot drops our ref we hold for
- * ->reloc_root. If it fails however we must
- * drop the ref ourselves.
- */
- ret2 = btrfs_drop_snapshot(reloc_root, 0, 1);
- if (ret2 < 0) {
- btrfs_put_root(reloc_root);
- if (!ret)
- ret = ret2;
- }
- }
- btrfs_put_root(root);
- } else {
- /* Orphan reloc tree, just clean it up */
- ret2 = btrfs_drop_snapshot(root, 0, 1);
- if (ret2 < 0) {
- btrfs_put_root(root);
- if (!ret)
- ret = ret2;
- }
- }
- }
- return ret;
- }
- /*
- * merge the relocated tree blocks in reloc tree with corresponding
- * fs tree.
- */
- static noinline_for_stack int merge_reloc_root(struct reloc_control *rc,
- struct btrfs_root *root)
- {
- struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
- struct btrfs_key key;
- struct btrfs_key next_key;
- struct btrfs_trans_handle *trans = NULL;
- struct btrfs_root *reloc_root;
- struct btrfs_root_item *root_item;
- struct btrfs_path *path;
- struct extent_buffer *leaf;
- int reserve_level;
- int level;
- int max_level;
- int replaced = 0;
- int ret;
- int err = 0;
- u32 min_reserved;
- path = btrfs_alloc_path();
- if (!path)
- return -ENOMEM;
- path->reada = READA_FORWARD;
- reloc_root = root->reloc_root;
- root_item = &reloc_root->root_item;
- if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
- level = btrfs_root_level(root_item);
- atomic_inc(&reloc_root->node->refs);
- 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);
- }
- /*
- * In merge_reloc_root(), we modify the upper level pointer to swap the
- * tree blocks between reloc tree and subvolume tree. Thus for tree
- * block COW, we COW at most from level 1 to root level for each tree.
- *
- * Thus the needed metadata size is at most root_level * nodesize,
- * and * 2 since we have two trees to COW.
- */
- reserve_level = max_t(int, 1, btrfs_root_level(root_item));
- min_reserved = fs_info->nodesize * reserve_level * 2;
- memset(&next_key, 0, sizeof(next_key));
- while (1) {
- ret = btrfs_block_rsv_refill(root, rc->block_rsv, min_reserved,
- BTRFS_RESERVE_FLUSH_LIMIT);
- if (ret) {
- err = ret;
- goto out;
- }
- trans = btrfs_start_transaction(root, 0);
- if (IS_ERR(trans)) {
- err = PTR_ERR(trans);
- trans = NULL;
- goto out;
- }
- /*
- * At this point we no longer have a reloc_control, so we can't
- * depend on btrfs_init_reloc_root to update our last_trans.
- *
- * But that's ok, we started the trans handle on our
- * corresponding fs_root, which means it's been added to the
- * dirty list. At commit time we'll still call
- * btrfs_update_reloc_root() and update our root item
- * appropriately.
- */
- reloc_root->last_trans = trans->transid;
- trans->block_rsv = rc->block_rsv;
- replaced = 0;
- max_level = level;
- ret = walk_down_reloc_tree(reloc_root, path, &level);
- if (ret < 0) {
- err = ret;
- goto out;
- }
- if (ret > 0)
- break;
- if (!find_next_key(path, level, &key) &&
- btrfs_comp_cpu_keys(&next_key, &key) >= 0) {
- ret = 0;
- } else {
- ret = replace_path(trans, rc, root, reloc_root, path,
- &next_key, level, max_level);
- }
- if (ret < 0) {
- err = ret;
- goto out;
- }
- if (ret > 0) {
- level = ret;
- btrfs_node_key_to_cpu(path->nodes[level], &key,
- path->slots[level]);
- replaced = 1;
- }
- ret = walk_up_reloc_tree(reloc_root, path, &level);
- if (ret > 0)
- break;
- BUG_ON(level == 0);
- /*
- * save the merging progress in the drop_progress.
- * this is OK since root refs == 1 in this case.
- */
- btrfs_node_key(path->nodes[level], &root_item->drop_progress,
- path->slots[level]);
- root_item->drop_level = level;
- btrfs_end_transaction_throttle(trans);
- trans = NULL;
- btrfs_btree_balance_dirty(fs_info);
- if (replaced && rc->stage == UPDATE_DATA_PTRS)
- invalidate_extent_cache(root, &key, &next_key);
- }
- /*
- * handle the case only one block in the fs tree need to be
- * relocated and the block is tree root.
- */
- leaf = btrfs_lock_root_node(root);
- ret = btrfs_cow_block(trans, root, leaf, NULL, 0, &leaf,
- BTRFS_NESTING_COW);
- btrfs_tree_unlock(leaf);
- free_extent_buffer(leaf);
- if (ret < 0)
- err = ret;
- out:
- btrfs_free_path(path);
- if (err == 0)
- insert_dirty_subvol(trans, rc, root);
- if (trans)
- btrfs_end_transaction_throttle(trans);
- btrfs_btree_balance_dirty(fs_info);
- if (replaced && rc->stage == UPDATE_DATA_PTRS)
- invalidate_extent_cache(root, &key, &next_key);
- return err;
- }
- static noinline_for_stack
- int prepare_to_merge(struct reloc_control *rc, int err)
- {
- struct btrfs_root *root = rc->extent_root;
- struct btrfs_fs_info *fs_info = root->fs_info;
- struct btrfs_root *reloc_root;
- struct btrfs_trans_handle *trans;
- LIST_HEAD(reloc_roots);
- u64 num_bytes = 0;
- int ret;
- mutex_lock(&fs_info->reloc_mutex);
- rc->merging_rsv_size += fs_info->nodesize * (BTRFS_MAX_LEVEL - 1) * 2;
- rc->merging_rsv_size += rc->nodes_relocated * 2;
- mutex_unlock(&fs_info->reloc_mutex);
- again:
- if (!err) {
- num_bytes = rc->merging_rsv_size;
- ret = btrfs_block_rsv_add(root, rc->block_rsv, num_bytes,
- BTRFS_RESERVE_FLUSH_ALL);
- if (ret)
- err = ret;
- }
- trans = btrfs_join_transaction(rc->extent_root);
- if (IS_ERR(trans)) {
- if (!err)
- btrfs_block_rsv_release(fs_info, rc->block_rsv,
- num_bytes, NULL);
- return PTR_ERR(trans);
- }
- if (!err) {
- if (num_bytes != rc->merging_rsv_size) {
- btrfs_end_transaction(trans);
- btrfs_block_rsv_release(fs_info, rc->block_rsv,
- num_bytes, NULL);
- goto again;
- }
- }
- rc->merge_reloc_tree = 1;
- while (!list_empty(&rc->reloc_roots)) {
- reloc_root = list_entry(rc->reloc_roots.next,
- struct btrfs_root, root_list);
- list_del_init(&reloc_root->root_list);
- root = btrfs_get_fs_root(fs_info, reloc_root->root_key.offset,
- false);
- BUG_ON(IS_ERR(root));
- BUG_ON(root->reloc_root != reloc_root);
- /*
- * set reference count to 1, so btrfs_recover_relocation
- * knows it should resumes merging
- */
- if (!err)
- btrfs_set_root_refs(&reloc_root->root_item, 1);
- btrfs_update_reloc_root(trans, root);
- list_add(&reloc_root->root_list, &reloc_roots);
- btrfs_put_root(root);
- }
- list_splice(&reloc_roots, &rc->reloc_roots);
- if (!err)
- btrfs_commit_transaction(trans);
- else
- btrfs_end_transaction(trans);
- return err;
- }
- static noinline_for_stack
- void free_reloc_roots(struct list_head *list)
- {
- struct btrfs_root *reloc_root, *tmp;
- list_for_each_entry_safe(reloc_root, tmp, list, root_list)
- __del_reloc_root(reloc_root);
- }
- static noinline_for_stack
- void merge_reloc_roots(struct reloc_control *rc)
- {
- struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
- struct btrfs_root *root;
- struct btrfs_root *reloc_root;
- LIST_HEAD(reloc_roots);
- int found = 0;
- int ret = 0;
- again:
- root = rc->extent_root;
- /*
- * this serializes us with btrfs_record_root_in_transaction,
- * we have to make sure nobody is in the middle of
- * adding their roots to the list while we are
- * doing this splice
- */
- mutex_lock(&fs_info->reloc_mutex);
- list_splice_init(&rc->reloc_roots, &reloc_roots);
- mutex_unlock(&fs_info->reloc_mutex);
- while (!list_empty(&reloc_roots)) {
- found = 1;
- reloc_root = list_entry(reloc_roots.next,
- struct btrfs_root, root_list);
- root = btrfs_get_fs_root(fs_info, reloc_root->root_key.offset,
- false);
- if (btrfs_root_refs(&reloc_root->root_item) > 0) {
- BUG_ON(IS_ERR(root));
- BUG_ON(root->reloc_root != reloc_root);
- ret = merge_reloc_root(rc, root);
- btrfs_put_root(root);
- if (ret) {
- if (list_empty(&reloc_root->root_list))
- list_add_tail(&reloc_root->root_list,
- &reloc_roots);
- goto out;
- }
- } else {
- if (!IS_ERR(root)) {
- if (root->reloc_root == reloc_root) {
- root->reloc_root = NULL;
- btrfs_put_root(reloc_root);
- }
- clear_bit(BTRFS_ROOT_DEAD_RELOC_TREE,
- &root->state);
- btrfs_put_root(root);
- }
- list_del_init(&reloc_root->root_list);
- /* Don't forget to queue this reloc root for cleanup */
- list_add_tail(&reloc_root->reloc_dirty_list,
- &rc->dirty_subvol_roots);
- }
- }
- if (found) {
- found = 0;
- goto again;
- }
- out:
- if (ret) {
- btrfs_handle_fs_error(fs_info, ret, NULL);
- free_reloc_roots(&reloc_roots);
- /* new reloc root may be added */
- mutex_lock(&fs_info->reloc_mutex);
- list_splice_init(&rc->reloc_roots, &reloc_roots);
- mutex_unlock(&fs_info->reloc_mutex);
- free_reloc_roots(&reloc_roots);
- }
- /*
- * We used to have
- *
- * BUG_ON(!RB_EMPTY_ROOT(&rc->reloc_root_tree.rb_root));
- *
- * here, but it's wrong. If we fail to start the transaction in
- * prepare_to_merge() we will have only 0 ref reloc roots, none of which
- * have actually been removed from the reloc_root_tree rb tree. This is
- * fine because we're bailing here, and we hold a reference on the root
- * for the list that holds it, so these roots will be cleaned up when we
- * do the reloc_dirty_list afterwards. Meanwhile the root->reloc_root
- * will be cleaned up on unmount.
- *
- * The remaining nodes will be cleaned up by free_reloc_control.
- */
- }
- static void free_block_list(struct rb_root *blocks)
- {
- struct tree_block *block;
- struct rb_node *rb_node;
- while ((rb_node = rb_first(blocks))) {
- block = rb_entry(rb_node, struct tree_block, rb_node);
- rb_erase(rb_node, blocks);
- kfree(block);
- }
- }
- static int record_reloc_root_in_trans(struct btrfs_trans_handle *trans,
- struct btrfs_root *reloc_root)
- {
- struct btrfs_fs_info *fs_info = reloc_root->fs_info;
- struct btrfs_root *root;
- int ret;
- if (reloc_root->last_trans == trans->transid)
- return 0;
- root = btrfs_get_fs_root(fs_info, reloc_root->root_key.offset, false);
- BUG_ON(IS_ERR(root));
- BUG_ON(root->reloc_root != reloc_root);
- ret = btrfs_record_root_in_trans(trans, root);
- btrfs_put_root(root);
- return ret;
- }
- static noinline_for_stack
- struct btrfs_root *select_reloc_root(struct btrfs_trans_handle *trans,
- struct reloc_control *rc,
- struct btrfs_backref_node *node,
- struct btrfs_backref_edge *edges[])
- {
- struct btrfs_backref_node *next;
- struct btrfs_root *root;
- int index = 0;
- next = node;
- while (1) {
- cond_resched();
- next = walk_up_backref(next, edges, &index);
- root = next->root;
- BUG_ON(!root);
- BUG_ON(!test_bit(BTRFS_ROOT_SHAREABLE, &root->state));
- if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) {
- record_reloc_root_in_trans(trans, root);
- break;
- }
- btrfs_record_root_in_trans(trans, root);
- root = root->reloc_root;
- if (next->new_bytenr != root->node->start) {
- BUG_ON(next->new_bytenr);
- BUG_ON(!list_empty(&next->list));
- next->new_bytenr = root->node->start;
- btrfs_put_root(next->root);
- next->root = btrfs_grab_root(root);
- ASSERT(next->root);
- list_add_tail(&next->list,
- &rc->backref_cache.changed);
- mark_block_processed(rc, next);
- break;
- }
- WARN_ON(1);
- root = NULL;
- next = walk_down_backref(edges, &index);
- if (!next || next->level <= node->level)
- break;
- }
- if (!root)
- return NULL;
- next = node;
- /* setup backref node path for btrfs_reloc_cow_block */
- while (1) {
- rc->backref_cache.path[next->level] = next;
- if (--index < 0)
- break;
- next = edges[index]->node[UPPER];
- }
- return root;
- }
- /*
- * Select a tree root for relocation.
- *
- * Return NULL if the block is not shareable. We should use do_relocation() in
- * this case.
- *
- * Return a tree root pointer if the block is shareable.
- * Return -ENOENT if the block is root of reloc tree.
- */
- static noinline_for_stack
- struct btrfs_root *select_one_root(struct btrfs_backref_node *node)
- {
- struct btrfs_backref_node *next;
- struct btrfs_root *root;
- struct btrfs_root *fs_root = NULL;
- struct btrfs_backref_edge *edges[BTRFS_MAX_LEVEL - 1];
- int index = 0;
- next = node;
- while (1) {
- cond_resched();
- next = walk_up_backref(next, edges, &index);
- root = next->root;
- BUG_ON(!root);
- /* No other choice for non-shareable tree */
- if (!test_bit(BTRFS_ROOT_SHAREABLE, &root->state))
- return root;
- if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID)
- fs_root = root;
- if (next != node)
- return NULL;
- next = walk_down_backref(edges, &index);
- if (!next || next->level <= node->level)
- break;
- }
- if (!fs_root)
- return ERR_PTR(-ENOENT);
- return fs_root;
- }
- static noinline_for_stack
- u64 calcu_metadata_size(struct reloc_control *rc,
- struct btrfs_backref_node *node, int reserve)
- {
- struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
- struct btrfs_backref_node *next = node;
- struct btrfs_backref_edge *edge;
- struct btrfs_backref_edge *edges[BTRFS_MAX_LEVEL - 1];
- u64 num_bytes = 0;
- int index = 0;
- BUG_ON(reserve && node->processed);
- while (next) {
- cond_resched();
- while (1) {
- if (next->processed && (reserve || next != node))
- break;
- num_bytes += fs_info->nodesize;
- if (list_empty(&next->upper))
- break;
- edge = list_entry(next->upper.next,
- struct btrfs_backref_edge, list[LOWER]);
- edges[index++] = edge;
- next = edge->node[UPPER];
- }
- next = walk_down_backref(edges, &index);
- }
- return num_bytes;
- }
- static int reserve_metadata_space(struct btrfs_trans_handle *trans,
- struct reloc_control *rc,
- struct btrfs_backref_node *node)
- {
- struct btrfs_root *root = rc->extent_root;
- struct btrfs_fs_info *fs_info = root->fs_info;
- u64 num_bytes;
- int ret;
- u64 tmp;
- num_bytes = calcu_metadata_size(rc, node, 1) * 2;
- trans->block_rsv = rc->block_rsv;
- rc->reserved_bytes += num_bytes;
- /*
- * We are under a transaction here so we can only do limited flushing.
- * If we get an enospc just kick back -EAGAIN so we know to drop the
- * transaction and try to refill when we can flush all the things.
- */
- ret = btrfs_block_rsv_refill(root, rc->block_rsv, num_bytes,
- BTRFS_RESERVE_FLUSH_LIMIT);
- if (ret) {
- tmp = fs_info->nodesize * RELOCATION_RESERVED_NODES;
- while (tmp <= rc->reserved_bytes)
- tmp <<= 1;
- /*
- * only one thread can access block_rsv at this point,
- * so we don't need hold lock to protect block_rsv.
- * we expand more reservation size here to allow enough
- * space for relocation and we will return earlier in
- * enospc case.
- */
- rc->block_rsv->size = tmp + fs_info->nodesize *
- RELOCATION_RESERVED_NODES;
- return -EAGAIN;
- }
- return 0;
- }
- /*
- * relocate a block tree, and then update pointers in upper level
- * blocks that reference the block to point to the new location.
- *
- * if called by link_to_upper, the block has already been relocated.
- * in that case this function just updates pointers.
- */
- static int do_relocation(struct btrfs_trans_handle *trans,
- struct reloc_control *rc,
- struct btrfs_backref_node *node,
- struct btrfs_key *key,
- struct btrfs_path *path, int lowest)
- {
- struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
- struct btrfs_backref_node *upper;
- struct btrfs_backref_edge *edge;
- struct btrfs_backref_edge *edges[BTRFS_MAX_LEVEL - 1];
- struct btrfs_root *root;
- struct extent_buffer *eb;
- u32 blocksize;
- u64 bytenr;
- u64 generation;
- int slot;
- int ret;
- int err = 0;
- BUG_ON(lowest && node->eb);
- path->lowest_level = node->level + 1;
- rc->backref_cache.path[node->level] = node;
- list_for_each_entry(edge, &node->upper, list[LOWER]) {
- struct btrfs_key first_key;
- struct btrfs_ref ref = { 0 };
- cond_resched();
- upper = edge->node[UPPER];
- root = select_reloc_root(trans, rc, upper, edges);
- BUG_ON(!root);
- if (upper->eb && !upper->locked) {
- if (!lowest) {
- ret = btrfs_bin_search(upper->eb, key, &slot);
- if (ret < 0) {
- err = ret;
- goto next;
- }
- BUG_ON(ret);
- bytenr = btrfs_node_blockptr(upper->eb, slot);
- if (node->eb->start == bytenr)
- goto next;
- }
- btrfs_backref_drop_node_buffer(upper);
- }
- if (!upper->eb) {
- ret = btrfs_search_slot(trans, root, key, path, 0, 1);
- if (ret) {
- if (ret < 0)
- err = ret;
- else
- err = -ENOENT;
- btrfs_release_path(path);
- break;
- }
- if (!upper->eb) {
- upper->eb = path->nodes[upper->level];
- path->nodes[upper->level] = NULL;
- } else {
- BUG_ON(upper->eb != path->nodes[upper->level]);
- }
- upper->locked = 1;
- path->locks[upper->level] = 0;
- slot = path->slots[upper->level];
- btrfs_release_path(path);
- } else {
- ret = btrfs_bin_search(upper->eb, key, &slot);
- if (ret < 0) {
- err = ret;
- goto next;
- }
- BUG_ON(ret);
- }
- bytenr = btrfs_node_blockptr(upper->eb, slot);
- if (lowest) {
- if (bytenr != node->bytenr) {
- btrfs_err(root->fs_info,
- "lowest leaf/node mismatch: bytenr %llu node->bytenr %llu slot %d upper %llu",
- bytenr, node->bytenr, slot,
- upper->eb->start);
- err = -EIO;
- goto next;
- }
- } else {
- if (node->eb->start == bytenr)
- goto next;
- }
- blocksize = root->fs_info->nodesize;
- generation = btrfs_node_ptr_generation(upper->eb, slot);
- btrfs_node_key_to_cpu(upper->eb, &first_key, slot);
- eb = read_tree_block(fs_info, bytenr, generation,
- upper->level - 1, &first_key);
- if (IS_ERR(eb)) {
- err = PTR_ERR(eb);
- goto next;
- } else if (!extent_buffer_uptodate(eb)) {
- free_extent_buffer(eb);
- err = -EIO;
- goto next;
- }
- btrfs_tree_lock(eb);
- btrfs_set_lock_blocking_write(eb);
- if (!node->eb) {
- ret = btrfs_cow_block(trans, root, eb, upper->eb,
- slot, &eb, BTRFS_NESTING_COW);
- btrfs_tree_unlock(eb);
- free_extent_buffer(eb);
- if (ret < 0) {
- err = ret;
- goto next;
- }
- BUG_ON(node->eb != eb);
- } else {
- btrfs_set_node_blockptr(upper->eb, slot,
- node->eb->start);
- btrfs_set_node_ptr_generation(upper->eb, slot,
- trans->transid);
- btrfs_mark_buffer_dirty(upper->eb);
- btrfs_init_generic_ref(&ref, BTRFS_ADD_DELAYED_REF,
- node->eb->start, blocksize,
- upper->eb->start);
- ref.real_root = root->root_key.objectid;
- btrfs_init_tree_ref(&ref, node->level,
- btrfs_header_owner(upper->eb));
- ret = btrfs_inc_extent_ref(trans, &ref);
- BUG_ON(ret);
- ret = btrfs_drop_subtree(trans, root, eb, upper->eb);
- BUG_ON(ret);
- }
- next:
- if (!upper->pending)
- btrfs_backref_drop_node_buffer(upper);
- else
- btrfs_backref_unlock_node_buffer(upper);
- if (err)
- break;
- }
- if (!err && node->pending) {
- btrfs_backref_drop_node_buffer(node);
- list_move_tail(&node->list, &rc->backref_cache.changed);
- node->pending = 0;
- }
- path->lowest_level = 0;
- BUG_ON(err == -ENOSPC);
- return err;
- }
- static int link_to_upper(struct btrfs_trans_handle *trans,
- struct reloc_control *rc,
- struct btrfs_backref_node *node,
- struct btrfs_path *path)
- {
- struct btrfs_key key;
- btrfs_node_key_to_cpu(node->eb, &key, 0);
- return do_relocation(trans, rc, node, &key, path, 0);
- }
- static int finish_pending_nodes(struct btrfs_trans_handle *trans,
- struct reloc_control *rc,
- struct btrfs_path *path, int err)
- {
- LIST_HEAD(list);
- struct btrfs_backref_cache *cache = &rc->backref_cache;
- struct btrfs_backref_node *node;
- int level;
- int ret;
- for (level = 0; level < BTRFS_MAX_LEVEL; level++) {
- while (!list_empty(&cache->pending[level])) {
- node = list_entry(cache->pending[level].next,
- struct btrfs_backref_node, list);
- list_move_tail(&node->list, &list);
- BUG_ON(!node->pending);
- if (!err) {
- ret = link_to_upper(trans, rc, node, path);
- if (ret < 0)
- err = ret;
- }
- }
- list_splice_init(&list, &cache->pending[level]);
- }
- return err;
- }
- /*
- * mark a block and all blocks directly/indirectly reference the block
- * as processed.
- */
- static void update_processed_blocks(struct reloc_control *rc,
- struct btrfs_backref_node *node)
- {
- struct btrfs_backref_node *next = node;
- struct btrfs_backref_edge *edge;
- struct btrfs_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 btrfs_backref_edge, list[LOWER]);
- edges[index++] = edge;
- next = edge->node[UPPER];
- }
- next = walk_down_backref(edges, &index);
- }
- }
- static int tree_block_processed(u64 bytenr, struct reloc_control *rc)
- {
- u32 blocksize = rc->extent_root->fs_info->nodesize;
- if (test_range_bit(&rc->processed_blocks, bytenr,
- bytenr + blocksize - 1, EXTENT_DIRTY, 1, NULL))
- return 1;
- return 0;
- }
- static int get_tree_block_key(struct btrfs_fs_info *fs_info,
- struct tree_block *block)
- {
- struct extent_buffer *eb;
- eb = read_tree_block(fs_info, block->bytenr, block->key.offset,
- block->level, NULL);
- if (IS_ERR(eb)) {
- return PTR_ERR(eb);
- } else if (!extent_buffer_uptodate(eb)) {
- free_extent_buffer(eb);
- return -EIO;
- }
- if (block->level == 0)
- btrfs_item_key_to_cpu(eb, &block->key, 0);
- else
- btrfs_node_key_to_cpu(eb, &block->key, 0);
- free_extent_buffer(eb);
- block->key_ready = 1;
- return 0;
- }
- /*
- * helper function to relocate a tree block
- */
- static int relocate_tree_block(struct btrfs_trans_handle *trans,
- struct reloc_control *rc,
- struct btrfs_backref_node *node,
- struct btrfs_key *key,
- struct btrfs_path *path)
- {
- struct btrfs_root *root;
- int ret = 0;
- if (!node)
- return 0;
- /*
- * If we fail here we want to drop our backref_node because we are going
- * to start over and regenerate the tree for it.
- */
- ret = reserve_metadata_space(trans, rc, node);
- if (ret)
- goto out;
- BUG_ON(node->processed);
- root = select_one_root(node);
- if (root == ERR_PTR(-ENOENT)) {
- update_processed_blocks(rc, node);
- goto out;
- }
- if (root) {
- if (test_bit(BTRFS_ROOT_SHAREABLE, &root->state)) {
- BUG_ON(node->new_bytenr);
- BUG_ON(!list_empty(&node->list));
- btrfs_record_root_in_trans(trans, root);
- root = root->reloc_root;
- node->new_bytenr = root->node->start;
- btrfs_put_root(node->root);
- node->root = btrfs_grab_root(root);
- ASSERT(node->root);
- list_add_tail(&node->list, &rc->backref_cache.changed);
- } else {
- path->lowest_level = node->level;
- ret = btrfs_search_slot(trans, root, key, path, 0, 1);
- btrfs_release_path(path);
- if (ret > 0)
- ret = 0;
- }
- if (!ret)
- update_processed_blocks(rc, node);
- } else {
- ret = do_relocation(trans, rc, node, key, path, 1);
- }
- out:
- if (ret || node->level == 0 || node->cowonly)
- btrfs_backref_cleanup_node(&rc->backref_cache, node);
- return ret;
- }
- /*
- * relocate a list of blocks
- */
- static noinline_for_stack
- int relocate_tree_blocks(struct btrfs_trans_handle *trans,
- struct reloc_control *rc, struct rb_root *blocks)
- {
- struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
- struct btrfs_backref_node *node;
- struct btrfs_path *path;
- struct tree_block *block;
- struct tree_block *next;
- int ret;
- int err = 0;
- path = btrfs_alloc_path();
- if (!path) {
- err = -ENOMEM;
- goto out_free_blocks;
- }
- /* Kick in readahead for tree blocks with missing keys */
- rbtree_postorder_for_each_entry_safe(block, next, blocks, rb_node) {
- if (!block->key_ready)
- readahead_tree_block(fs_info, block->bytenr);
- }
- /* Get first keys */
- rbtree_postorder_for_each_entry_safe(block, next, blocks, rb_node) {
- if (!block->key_ready) {
- err = get_tree_block_key(fs_info, block);
- if (err)
- goto out_free_path;
- }
- }
- /* Do tree relocation */
- rbtree_postorder_for_each_entry_safe(block, next, blocks, rb_node) {
- node = build_backref_tree(rc, &block->key,
- block->level, block->bytenr);
- if (IS_ERR(node)) {
- err = PTR_ERR(node);
- goto out;
- }
- ret = relocate_tree_block(trans, rc, node, &block->key,
- path);
- if (ret < 0) {
- err = ret;
- break;
- }
- }
- out:
- err = finish_pending_nodes(trans, rc, path, err);
- out_free_path:
- btrfs_free_path(path);
- out_free_blocks:
- free_block_list(blocks);
- return err;
- }
- static noinline_for_stack int prealloc_file_extent_cluster(
- struct btrfs_inode *inode,
- struct file_extent_cluster *cluster)
- {
- u64 alloc_hint = 0;
- u64 start;
- u64 end;
- u64 offset = inode->index_cnt;
- u64 num_bytes;
- int nr;
- int ret = 0;
- u64 prealloc_start = cluster->start - offset;
- u64 prealloc_end = cluster->end - offset;
- u64 cur_offset = prealloc_start;
- BUG_ON(cluster->start != cluster->boundary[0]);
- ret = btrfs_alloc_data_chunk_ondemand(inode,
- prealloc_end + 1 - prealloc_start);
- if (ret)
- return ret;
- inode_lock(&inode->vfs_inode);
- for (nr = 0; nr < cluster->nr; nr++) {
- start = cluster->boundary[nr] - offset;
- if (nr + 1 < cluster->nr)
- end = cluster->boundary[nr + 1] - 1 - offset;
- else
- end = cluster->end - offset;
- lock_extent(&inode->io_tree, start, end);
- num_bytes = end + 1 - start;
- ret = btrfs_prealloc_file_range(&inode->vfs_inode, 0, start,
- num_bytes, num_bytes,
- end + 1, &alloc_hint);
- cur_offset = end + 1;
- unlock_extent(&inode->io_tree, start, end);
- if (ret)
- break;
- }
- inode_unlock(&inode->vfs_inode);
- if (cur_offset < prealloc_end)
- btrfs_free_reserved_data_space_noquota(inode->root->fs_info,
- prealloc_end + 1 - cur_offset);
- return ret;
- }
- static noinline_for_stack
- int setup_extent_mapping(struct inode *inode, u64 start, u64 end,
- u64 block_start)
- {
- struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
- struct extent_map *em;
- int ret = 0;
- em = alloc_extent_map();
- if (!em)
- return -ENOMEM;
- em->start = start;
- em->len = end + 1 - start;
- em->block_len = em->len;
- em->block_start = block_start;
- set_bit(EXTENT_FLAG_PINNED, &em->flags);
- lock_extent(&BTRFS_I(inode)->io_tree, start, end);
- while (1) {
- write_lock(&em_tree->lock);
- ret = add_extent_mapping(em_tree, em, 0);
- write_unlock(&em_tree->lock);
- if (ret != -EEXIST) {
- free_extent_map(em);
- break;
- }
- btrfs_drop_extent_cache(BTRFS_I(inode), start, end, 0);
- }
- unlock_extent(&BTRFS_I(inode)->io_tree, start, end);
- return ret;
- }
- /*
- * Allow error injection to test balance cancellation
- */
- int btrfs_should_cancel_balance(struct btrfs_fs_info *fs_info)
- {
- return atomic_read(&fs_info->balance_cancel_req) ||
- fatal_signal_pending(current);
- }
- ALLOW_ERROR_INJECTION(btrfs_should_cancel_balance, TRUE);
- static int relocate_file_extent_cluster(struct inode *inode,
- struct file_extent_cluster *cluster)
- {
- struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
- u64 page_start;
- u64 page_end;
- u64 offset = BTRFS_I(inode)->index_cnt;
- unsigned long index;
- unsigned long last_index;
- struct page *page;
- struct file_ra_state *ra;
- gfp_t mask = btrfs_alloc_write_mask(inode->i_mapping);
- int nr = 0;
- int ret = 0;
- if (!cluster->nr)
- return 0;
- ra = kzalloc(sizeof(*ra), GFP_NOFS);
- if (!ra)
- return -ENOMEM;
- ret = prealloc_file_extent_cluster(BTRFS_I(inode), cluster);
- if (ret)
- goto out;
- file_ra_state_init(ra, inode->i_mapping);
- ret = setup_extent_mapping(inode, cluster->start - offset,
- cluster->end - offset, cluster->start);
- if (ret)
- goto out;
- index = (cluster->start - offset) >> PAGE_SHIFT;
- last_index = (cluster->end - offset) >> PAGE_SHIFT;
- while (index <= last_index) {
- ret = btrfs_delalloc_reserve_metadata(BTRFS_I(inode),
- PAGE_SIZE);
- if (ret)
- goto out;
- page = find_lock_page(inode->i_mapping, index);
- if (!page) {
- page_cache_sync_readahead(inode->i_mapping,
- ra, NULL, index,
- last_index + 1 - index);
- page = find_or_create_page(inode->i_mapping, index,
- mask);
- if (!page) {
- btrfs_delalloc_release_metadata(BTRFS_I(inode),
- PAGE_SIZE, true);
- btrfs_delalloc_release_extents(BTRFS_I(inode),
- PAGE_SIZE);
- ret = -ENOMEM;
- goto out;
- }
- }
- if (PageReadahead(page)) {
- page_cache_async_readahead(inode->i_mapping,
- ra, NULL, page, index,
- last_index + 1 - index);
- }
- if (!PageUptodate(page)) {
- btrfs_readpage(NULL, page);
- lock_page(page);
- if (!PageUptodate(page)) {
- unlock_page(page);
- put_page(page);
- btrfs_delalloc_release_metadata(BTRFS_I(inode),
- PAGE_SIZE, true);
- btrfs_delalloc_release_extents(BTRFS_I(inode),
- PAGE_SIZE);
- ret = -EIO;
- goto out;
- }
- }
- page_start = page_offset(page);
- page_end = page_start + PAGE_SIZE - 1;
- lock_extent(&BTRFS_I(inode)->io_tree, page_start, page_end);
- set_page_extent_mapped(page);
- if (nr < cluster->nr &&
- page_start + offset == cluster->boundary[nr]) {
- set_extent_bits(&BTRFS_I(inode)->io_tree,
- page_start, page_end,
- EXTENT_BOUNDARY);
- nr++;
- }
- ret = btrfs_set_extent_delalloc(BTRFS_I(inode), page_start,
- page_end, 0, NULL);
- if (ret) {
- unlock_page(page);
- put_page(page);
- btrfs_delalloc_release_metadata(BTRFS_I(inode),
- PAGE_SIZE, true);
- btrfs_delalloc_release_extents(BTRFS_I(inode),
- PAGE_SIZE);
- clear_extent_bits(&BTRFS_I(inode)->io_tree,
- page_start, page_end,
- EXTENT_LOCKED | EXTENT_BOUNDARY);
- goto out;
- }
- set_page_dirty(page);
- unlock_extent(&BTRFS_I(inode)->io_tree,
- page_start, page_end);
- unlock_page(page);
- put_page(page);
- index++;
- btrfs_delalloc_release_extents(BTRFS_I(inode), PAGE_SIZE);
- balance_dirty_pages_ratelimited(inode->i_mapping);
- btrfs_throttle(fs_info);
- if (btrfs_should_cancel_balance(fs_info)) {
- ret = -ECANCELED;
- goto out;
- }
- }
- WARN_ON(nr != cluster->nr);
- out:
- kfree(ra);
- return ret;
- }
- static noinline_for_stack
- int relocate_data_extent(struct inode *inode, struct btrfs_key *extent_key,
- struct file_extent_cluster *cluster)
- {
- int ret;
- if (cluster->nr > 0 && extent_key->objectid != cluster->end + 1) {
- ret = relocate_file_extent_cluster(inode, cluster);
- if (ret)
- return ret;
- cluster->nr = 0;
- }
- if (!cluster->nr)
- cluster->start = extent_key->objectid;
- else
- BUG_ON(cluster->nr >= MAX_EXTENTS);
- cluster->end = extent_key->objectid + extent_key->offset - 1;
- cluster->boundary[cluster->nr] = extent_key->objectid;
- cluster->nr++;
- if (cluster->nr >= MAX_EXTENTS) {
- ret = relocate_file_extent_cluster(inode, cluster);
- if (ret)
- return ret;
- cluster->nr = 0;
- }
- return 0;
- }
- /*
- * helper to add a tree block to the list.
- * the major work is getting the generation and level of the block
- */
- static int add_tree_block(struct reloc_control *rc,
- struct btrfs_key *extent_key,
- struct btrfs_path *path,
- struct rb_root *blocks)
- {
- struct extent_buffer *eb;
- struct btrfs_extent_item *ei;
- struct btrfs_tree_block_info *bi;
- struct tree_block *block;
- struct rb_node *rb_node;
- u32 item_size;
- int level = -1;
- u64 generation;
- eb = path->nodes[0];
- item_size = btrfs_item_size_nr(eb, path->slots[0]);
- if (extent_key->type == BTRFS_METADATA_ITEM_KEY ||
- item_size >= sizeof(*ei) + sizeof(*bi)) {
- ei = btrfs_item_ptr(eb, path->slots[0],
- struct btrfs_extent_item);
- if (extent_key->type == BTRFS_EXTENT_ITEM_KEY) {
- bi = (struct btrfs_tree_block_info *)(ei + 1);
- level = btrfs_tree_block_level(eb, bi);
- } else {
- level = (int)extent_key->offset;
- }
- generation = btrfs_extent_generation(eb, ei);
- } else if (unlikely(item_size == sizeof(struct btrfs_extent_item_v0))) {
- btrfs_print_v0_err(eb->fs_info);
- btrfs_handle_fs_error(eb->fs_info, -EINVAL, NULL);
- return -EINVAL;
- } else {
- BUG();
- }
- btrfs_release_path(path);
- BUG_ON(level == -1);
- block = kmalloc(sizeof(*block), GFP_NOFS);
- if (!block)
- return -ENOMEM;
- block->bytenr = extent_key->objectid;
- block->key.objectid = rc->extent_root->fs_info->nodesize;
- block->key.offset = generation;
- block->level = level;
- block->key_ready = 0;
- rb_node = rb_simple_insert(blocks, block->bytenr, &block->rb_node);
- if (rb_node)
- btrfs_backref_panic(rc->extent_root->fs_info, block->bytenr,
- -EEXIST);
- return 0;
- }
- /*
- * helper to add tree blocks for backref of type BTRFS_SHARED_DATA_REF_KEY
- */
- static int __add_tree_block(struct reloc_control *rc,
- u64 bytenr, u32 blocksize,
- struct rb_root *blocks)
- {
- struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
- struct btrfs_path *path;
- struct btrfs_key key;
- int ret;
- bool skinny = btrfs_fs_incompat(fs_info, SKINNY_METADATA);
- if (tree_block_processed(bytenr, rc))
- return 0;
- if (rb_simple_search(blocks, bytenr))
- return 0;
- path = btrfs_alloc_path();
- if (!path)
- return -ENOMEM;
- again:
- key.objectid = bytenr;
- if (skinny) {
- key.type = BTRFS_METADATA_ITEM_KEY;
- key.offset = (u64)-1;
- } else {
- key.type = BTRFS_EXTENT_ITEM_KEY;
- key.offset = blocksize;
- }
- path->search_commit_root = 1;
- path->skip_locking = 1;
- ret = btrfs_search_slot(NULL, rc->extent_root, &key, path, 0, 0);
- if (ret < 0)
- goto out;
- if (ret > 0 && skinny) {
- if (path->slots[0]) {
- path->slots[0]--;
- btrfs_item_key_to_cpu(path->nodes[0], &key,
- path->slots[0]);
- if (key.objectid == bytenr &&
- (key.type == BTRFS_METADATA_ITEM_KEY ||
- (key.type == BTRFS_EXTENT_ITEM_KEY &&
- key.offset == blocksize)))
- ret = 0;
- }
- if (ret) {
- skinny = false;
- btrfs_release_path(path);
- goto again;
- }
- }
- if (ret) {
- ASSERT(ret == 1);
- btrfs_print_leaf(path->nodes[0]);
- btrfs_err(fs_info,
- "tree block extent item (%llu) is not found in extent tree",
- bytenr);
- WARN_ON(1);
- ret = -EINVAL;
- goto out;
- }
- ret = add_tree_block(rc, &key, path, blocks);
- out:
- btrfs_free_path(path);
- return ret;
- }
- static int delete_block_group_cache(struct btrfs_fs_info *fs_info,
- struct btrfs_block_group *block_group,
- struct inode *inode,
- u64 ino)
- {
- struct btrfs_root *root = fs_info->tree_root;
- struct btrfs_trans_handle *trans;
- int ret = 0;
- if (inode)
- goto truncate;
- inode = btrfs_iget(fs_info->sb, ino, root);
- if (IS_ERR(inode))
- return -ENOENT;
- truncate:
- ret = btrfs_check_trunc_cache_free_space(fs_info,
- &fs_info->global_block_rsv);
- if (ret)
- goto out;
- trans = btrfs_join_transaction(root);
- if (IS_ERR(trans)) {
- ret = PTR_ERR(trans);
- goto out;
- }
- ret = btrfs_truncate_free_space_cache(trans, block_group, inode);
- btrfs_end_transaction(trans);
- btrfs_btree_balance_dirty(fs_info);
- out:
- iput(inode);
- return ret;
- }
- /*
- * Locate the free space cache EXTENT_DATA in root tree leaf and delete the
- * cache inode, to avoid free space cache data extent blocking data relocation.
- */
- static int delete_v1_space_cache(struct extent_buffer *leaf,
- struct btrfs_block_group *block_group,
- u64 data_bytenr)
- {
- u64 space_cache_ino;
- struct btrfs_file_extent_item *ei;
- struct btrfs_key key;
- bool found = false;
- int i;
- int ret;
- if (btrfs_header_owner(leaf) != BTRFS_ROOT_TREE_OBJECTID)
- return 0;
- for (i = 0; i < btrfs_header_nritems(leaf); i++) {
- u8 type;
- btrfs_item_key_to_cpu(leaf, &key, i);
- if (key.type != BTRFS_EXTENT_DATA_KEY)
- continue;
- ei = btrfs_item_ptr(leaf, i, struct btrfs_file_extent_item);
- type = btrfs_file_extent_type(leaf, ei);
- if ((type == BTRFS_FILE_EXTENT_REG ||
- type == BTRFS_FILE_EXTENT_PREALLOC) &&
- btrfs_file_extent_disk_bytenr(leaf, ei) == data_bytenr) {
- found = true;
- space_cache_ino = key.objectid;
- break;
- }
- }
- if (!found)
- return -ENOENT;
- ret = delete_block_group_cache(leaf->fs_info, block_group, NULL,
- space_cache_ino);
- return ret;
- }
- /*
- * helper to find all tree blocks that reference a given data extent
- */
- static noinline_for_stack
- int add_data_references(struct reloc_control *rc,
- struct btrfs_key *extent_key,
- struct btrfs_path *path,
- struct rb_root *blocks)
- {
- struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
- struct ulist *leaves = NULL;
- struct ulist_iterator leaf_uiter;
- struct ulist_node *ref_node = NULL;
- const u32 blocksize = fs_info->nodesize;
- int ret = 0;
- btrfs_release_path(path);
- ret = btrfs_find_all_leafs(NULL, fs_info, extent_key->objectid,
- 0, &leaves, NULL, true);
- if (ret < 0)
- return ret;
- ULIST_ITER_INIT(&leaf_uiter);
- while ((ref_node = ulist_next(leaves, &leaf_uiter))) {
- struct extent_buffer *eb;
- eb = read_tree_block(fs_info, ref_node->val, 0, 0, NULL);
- if (IS_ERR(eb)) {
- ret = PTR_ERR(eb);
- break;
- }
- ret = delete_v1_space_cache(eb, rc->block_group,
- extent_key->objectid);
- free_extent_buffer(eb);
- if (ret < 0)
- break;
- ret = __add_tree_block(rc, ref_node->val, blocksize, blocks);
- if (ret < 0)
- break;
- }
- if (ret < 0)
- free_block_list(blocks);
- ulist_free(leaves);
- return ret;
- }
- /*
- * helper to find next unprocessed extent
- */
- static noinline_for_stack
- int find_next_extent(struct reloc_control *rc, struct btrfs_path *path,
- struct btrfs_key *extent_key)
- {
- struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
- struct btrfs_key key;
- struct extent_buffer *leaf;
- u64 start, end, last;
- int ret;
- last = rc->block_group->start + rc->block_group->length;
- while (1) {
- cond_resched();
- if (rc->search_start >= last) {
- ret = 1;
- break;
- }
- key.objectid = rc->search_start;
- key.type = BTRFS_EXTENT_ITEM_KEY;
- key.offset = 0;
- path->search_commit_root = 1;
- path->skip_locking = 1;
- ret = btrfs_search_slot(NULL, rc->extent_root, &key, path,
- 0, 0);
- if (ret < 0)
- break;
- next:
- leaf = path->nodes[0];
- if (path->slots[0] >= btrfs_header_nritems(leaf)) {
- ret = btrfs_next_leaf(rc->extent_root, path);
- if (ret != 0)
- break;
- leaf = path->nodes[0];
- }
- btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
- if (key.objectid >= last) {
- ret = 1;
- break;
- }
- if (key.type != BTRFS_EXTENT_ITEM_KEY &&
- key.type != BTRFS_METADATA_ITEM_KEY) {
- path->slots[0]++;
- goto next;
- }
- if (key.type == BTRFS_EXTENT_ITEM_KEY &&
- key.objectid + key.offset <= rc->search_start) {
- path->slots[0]++;
- goto next;
- }
- if (key.type == BTRFS_METADATA_ITEM_KEY &&
- key.objectid + fs_info->nodesize <=
- rc->search_start) {
- path->slots[0]++;
- goto next;
- }
- ret = find_first_extent_bit(&rc->processed_blocks,
- key.objectid, &start, &end,
- EXTENT_DIRTY, NULL);
- if (ret == 0 && start <= key.objectid) {
- btrfs_release_path(path);
- rc->search_start = end + 1;
- } else {
- if (key.type == BTRFS_EXTENT_ITEM_KEY)
- rc->search_start = key.objectid + key.offset;
- else
- rc->search_start = key.objectid +
- fs_info->nodesize;
- memcpy(extent_key, &key, sizeof(key));
- return 0;
- }
- }
- btrfs_release_path(path);
- return ret;
- }
- static void set_reloc_control(struct reloc_control *rc)
- {
- struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
- mutex_lock(&fs_info->reloc_mutex);
- fs_info->reloc_ctl = rc;
- mutex_unlock(&fs_info->reloc_mutex);
- }
- static void unset_reloc_control(struct reloc_control *rc)
- {
- struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
- mutex_lock(&fs_info->reloc_mutex);
- fs_info->reloc_ctl = NULL;
- mutex_unlock(&fs_info->reloc_mutex);
- }
- static int check_extent_flags(u64 flags)
- {
- if ((flags & BTRFS_EXTENT_FLAG_DATA) &&
- (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK))
- return 1;
- if (!(flags & BTRFS_EXTENT_FLAG_DATA) &&
- !(flags & BTRFS_EXTENT_FLAG_TREE_BLOCK))
- return 1;
- if ((flags & BTRFS_EXTENT_FLAG_DATA) &&
- (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
- return 1;
- return 0;
- }
- static noinline_for_stack
- int prepare_to_relocate(struct reloc_control *rc)
- {
- struct btrfs_trans_handle *trans;
- int ret;
- rc->block_rsv = btrfs_alloc_block_rsv(rc->extent_root->fs_info,
- BTRFS_BLOCK_RSV_TEMP);
- if (!rc->block_rsv)
- return -ENOMEM;
- memset(&rc->cluster, 0, sizeof(rc->cluster));
- rc->search_start = rc->block_group->start;
- rc->extents_found = 0;
- rc->nodes_relocated = 0;
- rc->merging_rsv_size = 0;
- rc->reserved_bytes = 0;
- rc->block_rsv->size = rc->extent_root->fs_info->nodesize *
- RELOCATION_RESERVED_NODES;
- ret = btrfs_block_rsv_refill(rc->extent_root,
- rc->block_rsv, rc->block_rsv->size,
- BTRFS_RESERVE_FLUSH_ALL);
- if (ret)
- return ret;
- rc->create_reloc_tree = 1;
- set_reloc_control(rc);
- trans = btrfs_join_transaction(rc->extent_root);
- if (IS_ERR(trans)) {
- unset_reloc_control(rc);
- /*
- * extent tree is not a ref_cow tree and has no reloc_root to
- * cleanup. And callers are responsible to free the above
- * block rsv.
- */
- return PTR_ERR(trans);
- }
- btrfs_commit_transaction(trans);
- return 0;
- }
- static noinline_for_stack int relocate_block_group(struct reloc_control *rc)
- {
- struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
- struct rb_root blocks = RB_ROOT;
- struct btrfs_key key;
- struct btrfs_trans_handle *trans = NULL;
- struct btrfs_path *path;
- struct btrfs_extent_item *ei;
- u64 flags;
- u32 item_size;
- int ret;
- int err = 0;
- int progress = 0;
- path = btrfs_alloc_path();
- if (!path)
- return -ENOMEM;
- path->reada = READA_FORWARD;
- ret = prepare_to_relocate(rc);
- if (ret) {
- err = ret;
- goto out_free;
- }
- while (1) {
- rc->reserved_bytes = 0;
- ret = btrfs_block_rsv_refill(rc->extent_root,
- rc->block_rsv, rc->block_rsv->size,
- BTRFS_RESERVE_FLUSH_ALL);
- if (ret) {
- err = ret;
- break;
- }
- progress++;
- trans = btrfs_start_transaction(rc->extent_root, 0);
- if (IS_ERR(trans)) {
- err = PTR_ERR(trans);
- trans = NULL;
- break;
- }
- restart:
- if (update_backref_cache(trans, &rc->backref_cache)) {
- btrfs_end_transaction(trans);
- trans = NULL;
- continue;
- }
- ret = find_next_extent(rc, path, &key);
- if (ret < 0)
- err = ret;
- if (ret != 0)
- break;
- rc->extents_found++;
- ei = btrfs_item_ptr(path->nodes[0], path->slots[0],
- struct btrfs_extent_item);
- item_size = btrfs_item_size_nr(path->nodes[0], path->slots[0]);
- if (item_size >= sizeof(*ei)) {
- flags = btrfs_extent_flags(path->nodes[0], ei);
- ret = check_extent_flags(flags);
- BUG_ON(ret);
- } else if (unlikely(item_size == sizeof(struct btrfs_extent_item_v0))) {
- err = -EINVAL;
- btrfs_print_v0_err(trans->fs_info);
- btrfs_abort_transaction(trans, err);
- break;
- } else {
- BUG();
- }
- if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
- ret = add_tree_block(rc, &key, path, &blocks);
- } else if (rc->stage == UPDATE_DATA_PTRS &&
- (flags & BTRFS_EXTENT_FLAG_DATA)) {
- ret = add_data_references(rc, &key, path, &blocks);
- } else {
- btrfs_release_path(path);
- ret = 0;
- }
- if (ret < 0) {
- err = ret;
- break;
- }
- if (!RB_EMPTY_ROOT(&blocks)) {
- ret = relocate_tree_blocks(trans, rc, &blocks);
- if (ret < 0) {
- if (ret != -EAGAIN) {
- err = ret;
- break;
- }
- rc->extents_found--;
- rc->search_start = key.objectid;
- }
- }
- btrfs_end_transaction_throttle(trans);
- btrfs_btree_balance_dirty(fs_info);
- trans = NULL;
- if (rc->stage == MOVE_DATA_EXTENTS &&
- (flags & BTRFS_EXTENT_FLAG_DATA)) {
- rc->found_file_extent = 1;
- ret = relocate_data_extent(rc->data_inode,
- &key, &rc->cluster);
- if (ret < 0) {
- err = ret;
- break;
- }
- }
- if (btrfs_should_cancel_balance(fs_info)) {
- err = -ECANCELED;
- break;
- }
- }
- if (trans && progress && err == -ENOSPC) {
- ret = btrfs_force_chunk_alloc(trans, rc->block_group->flags);
- if (ret == 1) {
- err = 0;
- progress = 0;
- goto restart;
- }
- }
- btrfs_release_path(path);
- clear_extent_bits(&rc->processed_blocks, 0, (u64)-1, EXTENT_DIRTY);
- if (trans) {
- btrfs_end_transaction_throttle(trans);
- btrfs_btree_balance_dirty(fs_info);
- }
- if (!err) {
- ret = relocate_file_extent_cluster(rc->data_inode,
- &rc->cluster);
- if (ret < 0)
- err = ret;
- }
- rc->create_reloc_tree = 0;
- set_reloc_control(rc);
- btrfs_backref_release_cache(&rc->backref_cache);
- btrfs_block_rsv_release(fs_info, rc->block_rsv, (u64)-1, NULL);
- /*
- * Even in the case when the relocation is cancelled, we should all go
- * through prepare_to_merge() and merge_reloc_roots().
- *
- * For error (including cancelled balance), prepare_to_merge() will
- * mark all reloc trees orphan, then queue them for cleanup in
- * merge_reloc_roots()
- */
- err = prepare_to_merge(rc, err);
- merge_reloc_roots(rc);
- rc->merge_reloc_tree = 0;
- unset_reloc_control(rc);
- btrfs_block_rsv_release(fs_info, rc->block_rsv, (u64)-1, NULL);
- /* get rid of pinned extents */
- trans = btrfs_join_transaction(rc->extent_root);
- if (IS_ERR(trans)) {
- err = PTR_ERR(trans);
- goto out_free;
- }
- btrfs_commit_transaction(trans);
- out_free:
- ret = clean_dirty_subvols(rc);
- if (ret < 0 && !err)
- err = ret;
- btrfs_free_block_rsv(fs_info, rc->block_rsv);
- btrfs_free_path(path);
- return err;
- }
- static int __insert_orphan_inode(struct btrfs_trans_handle *trans,
- struct btrfs_root *root, u64 objectid)
- {
- struct btrfs_path *path;
- struct btrfs_inode_item *item;
- struct extent_buffer *leaf;
- int ret;
- path = btrfs_alloc_path();
- if (!path)
- return -ENOMEM;
- ret = btrfs_insert_empty_inode(trans, root, path, objectid);
- if (ret)
- goto out;
- leaf = path->nodes[0];
- item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_inode_item);
- memzero_extent_buffer(leaf, (unsigned long)item, sizeof(*item));
- btrfs_set_inode_generation(leaf, item, 1);
- btrfs_set_inode_size(leaf, item, 0);
- btrfs_set_inode_mode(leaf, item, S_IFREG | 0600);
- btrfs_set_inode_flags(leaf, item, BTRFS_INODE_NOCOMPRESS |
- BTRFS_INODE_PREALLOC);
- btrfs_mark_buffer_dirty(leaf);
- out:
- btrfs_free_path(path);
- return ret;
- }
- /*
- * helper to create inode for data relocation.
- * the inode is in data relocation tree and its link count is 0
- */
- static noinline_for_stack
- struct inode *create_reloc_inode(struct btrfs_fs_info *fs_info,
- struct btrfs_block_group *group)
- {
- struct inode *inode = NULL;
- struct btrfs_trans_handle *trans;
- struct btrfs_root *root;
- u64 objectid;
- int err = 0;
- root = btrfs_grab_root(fs_info->data_reloc_root);
- trans = btrfs_start_transaction(root, 6);
- if (IS_ERR(trans)) {
- btrfs_put_root(root);
- return ERR_CAST(trans);
- }
- err = btrfs_find_free_objectid(root, &objectid);
- if (err)
- goto out;
- err = __insert_orphan_inode(trans, root, objectid);
- BUG_ON(err);
- inode = btrfs_iget(fs_info->sb, objectid, root);
- BUG_ON(IS_ERR(inode));
- BTRFS_I(inode)->index_cnt = group->start;
- err = btrfs_orphan_add(trans, BTRFS_I(inode));
- out:
- btrfs_put_root(root);
- btrfs_end_transaction(trans);
- btrfs_btree_balance_dirty(fs_info);
- if (err) {
- if (inode)
- iput(inode);
- inode = ERR_PTR(err);
- }
- return inode;
- }
- static struct reloc_control *alloc_reloc_control(struct btrfs_fs_info *fs_info)
- {
- struct reloc_control *rc;
- rc = kzalloc(sizeof(*rc), GFP_NOFS);
- if (!rc)
- return NULL;
- INIT_LIST_HEAD(&rc->reloc_roots);
- INIT_LIST_HEAD(&rc->dirty_subvol_roots);
- btrfs_backref_init_cache(fs_info, &rc->backref_cache, 1);
- mapping_tree_init(&rc->reloc_root_tree);
- extent_io_tree_init(fs_info, &rc->processed_blocks,
- IO_TREE_RELOC_BLOCKS, NULL);
- return rc;
- }
- static void free_reloc_control(struct reloc_control *rc)
- {
- struct mapping_node *node, *tmp;
- free_reloc_roots(&rc->reloc_roots);
- rbtree_postorder_for_each_entry_safe(node, tmp,
- &rc->reloc_root_tree.rb_root, rb_node)
- kfree(node);
- kfree(rc);
- }
- /*
- * Print the block group being relocated
- */
- static void describe_relocation(struct btrfs_fs_info *fs_info,
- struct btrfs_block_group *block_group)
- {
- char buf[128] = {'\0'};
- btrfs_describe_block_groups(block_group->flags, buf, sizeof(buf));
- btrfs_info(fs_info,
- "relocating block group %llu flags %s",
- block_group->start, buf);
- }
- static const char *stage_to_string(int stage)
- {
- if (stage == MOVE_DATA_EXTENTS)
- return "move data extents";
- if (stage == UPDATE_DATA_PTRS)
- return "update data pointers";
- return "unknown";
- }
- /*
- * function to relocate all extents in a block group.
- */
- int btrfs_relocate_block_group(struct btrfs_fs_info *fs_info, u64 group_start)
- {
- struct btrfs_block_group *bg;
- struct btrfs_root *extent_root = fs_info->extent_root;
- struct reloc_control *rc;
- struct inode *inode;
- struct btrfs_path *path;
- int ret;
- int rw = 0;
- int err = 0;
- bg = btrfs_lookup_block_group(fs_info, group_start);
- if (!bg)
- return -ENOENT;
- if (btrfs_pinned_by_swapfile(fs_info, bg)) {
- btrfs_put_block_group(bg);
- return -ETXTBSY;
- }
- rc = alloc_reloc_control(fs_info);
- if (!rc) {
- btrfs_put_block_group(bg);
- return -ENOMEM;
- }
- rc->extent_root = extent_root;
- rc->block_group = bg;
- ret = btrfs_inc_block_group_ro(rc->block_group, true);
- if (ret) {
- err = ret;
- goto out;
- }
- rw = 1;
- path = btrfs_alloc_path();
- if (!path) {
- err = -ENOMEM;
- goto out;
- }
- inode = lookup_free_space_inode(rc->block_group, path);
- btrfs_free_path(path);
- if (!IS_ERR(inode))
- ret = delete_block_group_cache(fs_info, rc->block_group, inode, 0);
- else
- ret = PTR_ERR(inode);
- if (ret && ret != -ENOENT) {
- err = ret;
- goto out;
- }
- rc->data_inode = create_reloc_inode(fs_info, rc->block_group);
- if (IS_ERR(rc->data_inode)) {
- err = PTR_ERR(rc->data_inode);
- rc->data_inode = NULL;
- goto out;
- }
- describe_relocation(fs_info, rc->block_group);
- btrfs_wait_block_group_reservations(rc->block_group);
- btrfs_wait_nocow_writers(rc->block_group);
- btrfs_wait_ordered_roots(fs_info, U64_MAX,
- rc->block_group->start,
- rc->block_group->length);
- while (1) {
- int finishes_stage;
- mutex_lock(&fs_info->cleaner_mutex);
- ret = relocate_block_group(rc);
- mutex_unlock(&fs_info->cleaner_mutex);
- if (ret < 0)
- err = ret;
- finishes_stage = rc->stage;
- /*
- * We may have gotten ENOSPC after we already dirtied some
- * extents. If writeout happens while we're relocating a
- * different block group we could end up hitting the
- * BUG_ON(rc->stage == UPDATE_DATA_PTRS) in
- * btrfs_reloc_cow_block. Make sure we write everything out
- * properly so we don't trip over this problem, and then break
- * out of the loop if we hit an error.
- */
- if (rc->stage == MOVE_DATA_EXTENTS && rc->found_file_extent) {
- ret = btrfs_wait_ordered_range(rc->data_inode, 0,
- (u64)-1);
- if (ret)
- err = ret;
- invalidate_mapping_pages(rc->data_inode->i_mapping,
- 0, -1);
- rc->stage = UPDATE_DATA_PTRS;
- }
- if (err < 0)
- goto out;
- if (rc->extents_found == 0)
- break;
- btrfs_info(fs_info, "found %llu extents, stage: %s",
- rc->extents_found, stage_to_string(finishes_stage));
- }
- WARN_ON(rc->block_group->pinned > 0);
- WARN_ON(rc->block_group->reserved > 0);
- WARN_ON(rc->block_group->used > 0);
- out:
- if (err && rw)
- btrfs_dec_block_group_ro(rc->block_group);
- iput(rc->data_inode);
- btrfs_put_block_group(rc->block_group);
- free_reloc_control(rc);
- return err;
- }
- static noinline_for_stack int mark_garbage_root(struct btrfs_root *root)
- {
- struct btrfs_fs_info *fs_info = root->fs_info;
- struct btrfs_trans_handle *trans;
- int ret, err;
- trans = btrfs_start_transaction(fs_info->tree_root, 0);
- if (IS_ERR(trans))
- return PTR_ERR(trans);
- memset(&root->root_item.drop_progress, 0,
- sizeof(root->root_item.drop_progress));
- root->root_item.drop_level = 0;
- btrfs_set_root_refs(&root->root_item, 0);
- ret = btrfs_update_root(trans, fs_info->tree_root,
- &root->root_key, &root->root_item);
- err = btrfs_end_transaction(trans);
- if (err)
- return err;
- return ret;
- }
- /*
- * recover relocation interrupted by system crash.
- *
- * this function resumes merging reloc trees with corresponding fs trees.
- * this is important for keeping the sharing of tree blocks
- */
- int btrfs_recover_relocation(struct btrfs_root *root)
- {
- struct btrfs_fs_info *fs_info = root->fs_info;
- LIST_HEAD(reloc_roots);
- struct btrfs_key key;
- struct btrfs_root *fs_root;
- struct btrfs_root *reloc_root;
- struct btrfs_path *path;
- struct extent_buffer *leaf;
- struct reloc_control *rc = NULL;
- struct btrfs_trans_handle *trans;
- int ret;
- int err = 0;
- path = btrfs_alloc_path();
- if (!path)
- return -ENOMEM;
- path->reada = READA_BACK;
- key.objectid = BTRFS_TREE_RELOC_OBJECTID;
- key.type = BTRFS_ROOT_ITEM_KEY;
- key.offset = (u64)-1;
- while (1) {
- ret = btrfs_search_slot(NULL, fs_info->tree_root, &key,
- path, 0, 0);
- if (ret < 0) {
- err = ret;
- goto out;
- }
- if (ret > 0) {
- if (path->slots[0] == 0)
- break;
- path->slots[0]--;
- }
- leaf = path->nodes[0];
- btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
- btrfs_release_path(path);
- if (key.objectid != BTRFS_TREE_RELOC_OBJECTID ||
- key.type != BTRFS_ROOT_ITEM_KEY)
- break;
- reloc_root = btrfs_read_tree_root(root, &key);
- if (IS_ERR(reloc_root)) {
- err = PTR_ERR(reloc_root);
- goto out;
- }
- set_bit(BTRFS_ROOT_SHAREABLE, &reloc_root->state);
- list_add(&reloc_root->root_list, &reloc_roots);
- if (btrfs_root_refs(&reloc_root->root_item) > 0) {
- fs_root = btrfs_get_fs_root(fs_info,
- reloc_root->root_key.offset, false);
- if (IS_ERR(fs_root)) {
- ret = PTR_ERR(fs_root);
- if (ret != -ENOENT) {
- err = ret;
- goto out;
- }
- ret = mark_garbage_root(reloc_root);
- if (ret < 0) {
- err = ret;
- goto out;
- }
- } else {
- btrfs_put_root(fs_root);
- }
- }
- if (key.offset == 0)
- break;
- key.offset--;
- }
- btrfs_release_path(path);
- if (list_empty(&reloc_roots))
- goto out;
- rc = alloc_reloc_control(fs_info);
- if (!rc) {
- err = -ENOMEM;
- goto out;
- }
- rc->extent_root = fs_info->extent_root;
- set_reloc_control(rc);
- trans = btrfs_join_transaction(rc->extent_root);
- if (IS_ERR(trans)) {
- err = PTR_ERR(trans);
- goto out_unset;
- }
- rc->merge_reloc_tree = 1;
- while (!list_empty(&reloc_roots)) {
- reloc_root = list_entry(reloc_roots.next,
- struct btrfs_root, root_list);
- list_del(&reloc_root->root_list);
- if (btrfs_root_refs(&reloc_root->root_item) == 0) {
- list_add_tail(&reloc_root->root_list,
- &rc->reloc_roots);
- continue;
- }
- fs_root = btrfs_get_fs_root(fs_info, reloc_root->root_key.offset,
- false);
- if (IS_ERR(fs_root)) {
- err = PTR_ERR(fs_root);
- list_add_tail(&reloc_root->root_list, &reloc_roots);
- btrfs_end_transaction(trans);
- goto out_unset;
- }
- err = __add_reloc_root(reloc_root);
- BUG_ON(err < 0); /* -ENOMEM or logic error */
- fs_root->reloc_root = btrfs_grab_root(reloc_root);
- btrfs_put_root(fs_root);
- }
- err = btrfs_commit_transaction(trans);
- if (err)
- goto out_unset;
- merge_reloc_roots(rc);
- unset_reloc_control(rc);
- trans = btrfs_join_transaction(rc->extent_root);
- if (IS_ERR(trans)) {
- err = PTR_ERR(trans);
- goto out_clean;
- }
- err = btrfs_commit_transaction(trans);
- out_clean:
- ret = clean_dirty_subvols(rc);
- if (ret < 0 && !err)
- err = ret;
- out_unset:
- unset_reloc_control(rc);
- free_reloc_control(rc);
- out:
- free_reloc_roots(&reloc_roots);
- btrfs_free_path(path);
- if (err == 0) {
- /* cleanup orphan inode in data relocation tree */
- fs_root = btrfs_grab_root(fs_info->data_reloc_root);
- ASSERT(fs_root);
- err = btrfs_orphan_cleanup(fs_root);
- btrfs_put_root(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 btrfs_inode *inode, u64 file_pos, u64 len)
- {
- struct btrfs_fs_info *fs_info = inode->root->fs_info;
- struct btrfs_ordered_sum *sums;
- struct btrfs_ordered_extent *ordered;
- int ret;
- u64 disk_bytenr;
- u64 new_bytenr;
- LIST_HEAD(list);
- ordered = btrfs_lookup_ordered_extent(inode, file_pos);
- BUG_ON(ordered->file_offset != file_pos || ordered->num_bytes != len);
- disk_bytenr = file_pos + inode->index_cnt;
- ret = btrfs_lookup_csums_range(fs_info->csum_root, disk_bytenr,
- disk_bytenr + len - 1, &list, 0);
- if (ret)
- goto out;
- while (!list_empty(&list)) {
- sums = list_entry(list.next, struct btrfs_ordered_sum, list);
- list_del_init(&sums->list);
- /*
- * We need to offset the new_bytenr based on where the csum is.
- * We need to do this because we will read in entire prealloc
- * extents but we may have written to say the middle of the
- * prealloc extent, so we need to make sure the csum goes with
- * the right disk offset.
- *
- * We can do this because the data reloc inode refers strictly
- * to the on disk bytes, so we don't have to worry about
- * disk_len vs real len like with real inodes since it's all
- * disk length.
- */
- new_bytenr = ordered->disk_bytenr + sums->bytenr - disk_bytenr;
- sums->bytenr = new_bytenr;
- btrfs_add_ordered_sum(ordered, sums);
- }
- out:
- btrfs_put_ordered_extent(ordered);
- return ret;
- }
- int btrfs_reloc_cow_block(struct btrfs_trans_handle *trans,
- struct btrfs_root *root, struct extent_buffer *buf,
- struct extent_buffer *cow)
- {
- struct btrfs_fs_info *fs_info = root->fs_info;
- struct reloc_control *rc;
- struct btrfs_backref_node *node;
- int first_cow = 0;
- int level;
- int ret = 0;
- rc = fs_info->reloc_ctl;
- if (!rc)
- return 0;
- BUG_ON(rc->stage == UPDATE_DATA_PTRS &&
- root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID);
- level = btrfs_header_level(buf);
- if (btrfs_header_generation(buf) <=
- btrfs_root_last_snapshot(&root->root_item))
- first_cow = 1;
- if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID &&
- rc->create_reloc_tree) {
- WARN_ON(!first_cow && level == 0);
- node = rc->backref_cache.path[level];
- BUG_ON(node->bytenr != buf->start &&
- node->new_bytenr != buf->start);
- btrfs_backref_drop_node_buffer(node);
- atomic_inc(&cow->refs);
- node->eb = cow;
- node->new_bytenr = cow->start;
- if (!node->pending) {
- list_move_tail(&node->list,
- &rc->backref_cache.pending[level]);
- node->pending = 1;
- }
- if (first_cow)
- mark_block_processed(rc, node);
- if (first_cow && level > 0)
- rc->nodes_relocated += buf->len;
- }
- if (level == 0 && first_cow && rc->stage == UPDATE_DATA_PTRS)
- ret = replace_file_extents(trans, rc, root, cow);
- return ret;
- }
- /*
- * called before creating snapshot. it calculates metadata reservation
- * required for relocating tree blocks in the snapshot
- */
- void btrfs_reloc_pre_snapshot(struct btrfs_pending_snapshot *pending,
- u64 *bytes_to_reserve)
- {
- struct btrfs_root *root = pending->root;
- struct reloc_control *rc = root->fs_info->reloc_ctl;
- if (!rc || !have_reloc_root(root))
- return;
- if (!rc->merge_reloc_tree)
- return;
- root = root->reloc_root;
- BUG_ON(btrfs_root_refs(&root->root_item) == 0);
- /*
- * relocation is in the stage of merging trees. the space
- * used by merging a reloc tree is twice the size of
- * relocated tree nodes in the worst case. half for cowing
- * the reloc tree, half for cowing the fs tree. the space
- * used by cowing the reloc tree will be freed after the
- * tree is dropped. if we create snapshot, cowing the fs
- * tree may use more space than it frees. so we need
- * reserve extra space.
- */
- *bytes_to_reserve += rc->nodes_relocated;
- }
- /*
- * called after snapshot is created. migrate block reservation
- * and create reloc root for the newly created snapshot
- *
- * This is similar to btrfs_init_reloc_root(), we come out of here with two
- * references held on the reloc_root, one for root->reloc_root and one for
- * rc->reloc_roots.
- */
- int btrfs_reloc_post_snapshot(struct btrfs_trans_handle *trans,
- struct btrfs_pending_snapshot *pending)
- {
- struct btrfs_root *root = pending->root;
- struct btrfs_root *reloc_root;
- struct btrfs_root *new_root;
- struct reloc_control *rc = root->fs_info->reloc_ctl;
- int ret;
- if (!rc || !have_reloc_root(root))
- return 0;
- rc = root->fs_info->reloc_ctl;
- rc->merging_rsv_size += rc->nodes_relocated;
- if (rc->merge_reloc_tree) {
- ret = btrfs_block_rsv_migrate(&pending->block_rsv,
- rc->block_rsv,
- rc->nodes_relocated, true);
- if (ret)
- return ret;
- }
- new_root = pending->snap;
- reloc_root = create_reloc_root(trans, root->reloc_root,
- new_root->root_key.objectid);
- if (IS_ERR(reloc_root))
- return PTR_ERR(reloc_root);
- ret = __add_reloc_root(reloc_root);
- BUG_ON(ret < 0);
- new_root->reloc_root = btrfs_grab_root(reloc_root);
- if (rc->create_reloc_tree)
- ret = clone_backref_node(trans, rc, root, reloc_root);
- return ret;
- }
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