1155 lines
30 KiB
C
1155 lines
30 KiB
C
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/*
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* Copyright (C) 2007 Oracle. All rights reserved.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public
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* License v2 as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public
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* License along with this program; if not, write to the
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* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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* Boston, MA 021110-1307, USA.
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*/
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#include <linux/fs.h>
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#include <linux/sched.h>
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#include <linux/writeback.h>
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#include <linux/pagemap.h>
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#include <linux/blkdev.h>
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#include "ctree.h"
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#include "disk-io.h"
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#include "transaction.h"
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#include "locking.h"
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#include "tree-log.h"
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#define BTRFS_ROOT_TRANS_TAG 0
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static noinline void put_transaction(struct btrfs_transaction *transaction)
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{
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WARN_ON(transaction->use_count == 0);
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transaction->use_count--;
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if (transaction->use_count == 0) {
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list_del_init(&transaction->list);
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memset(transaction, 0, sizeof(*transaction));
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kmem_cache_free(btrfs_transaction_cachep, transaction);
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}
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}
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static noinline void switch_commit_root(struct btrfs_root *root)
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{
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free_extent_buffer(root->commit_root);
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root->commit_root = btrfs_root_node(root);
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}
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/*
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* either allocate a new transaction or hop into the existing one
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*/
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static noinline int join_transaction(struct btrfs_root *root)
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{
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struct btrfs_transaction *cur_trans;
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cur_trans = root->fs_info->running_transaction;
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if (!cur_trans) {
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cur_trans = kmem_cache_alloc(btrfs_transaction_cachep,
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GFP_NOFS);
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BUG_ON(!cur_trans);
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root->fs_info->generation++;
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cur_trans->num_writers = 1;
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cur_trans->num_joined = 0;
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cur_trans->transid = root->fs_info->generation;
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init_waitqueue_head(&cur_trans->writer_wait);
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init_waitqueue_head(&cur_trans->commit_wait);
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cur_trans->in_commit = 0;
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cur_trans->blocked = 0;
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cur_trans->use_count = 1;
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cur_trans->commit_done = 0;
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cur_trans->start_time = get_seconds();
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cur_trans->delayed_refs.root.rb_node = NULL;
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cur_trans->delayed_refs.num_entries = 0;
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cur_trans->delayed_refs.num_heads_ready = 0;
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cur_trans->delayed_refs.num_heads = 0;
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cur_trans->delayed_refs.flushing = 0;
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cur_trans->delayed_refs.run_delayed_start = 0;
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spin_lock_init(&cur_trans->delayed_refs.lock);
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INIT_LIST_HEAD(&cur_trans->pending_snapshots);
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list_add_tail(&cur_trans->list, &root->fs_info->trans_list);
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extent_io_tree_init(&cur_trans->dirty_pages,
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root->fs_info->btree_inode->i_mapping,
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GFP_NOFS);
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spin_lock(&root->fs_info->new_trans_lock);
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root->fs_info->running_transaction = cur_trans;
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spin_unlock(&root->fs_info->new_trans_lock);
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} else {
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cur_trans->num_writers++;
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cur_trans->num_joined++;
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}
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return 0;
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}
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/*
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* this does all the record keeping required to make sure that a reference
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* counted root is properly recorded in a given transaction. This is required
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* to make sure the old root from before we joined the transaction is deleted
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* when the transaction commits
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*/
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static noinline int record_root_in_trans(struct btrfs_trans_handle *trans,
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struct btrfs_root *root)
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{
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if (root->ref_cows && root->last_trans < trans->transid) {
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WARN_ON(root == root->fs_info->extent_root);
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WARN_ON(root->commit_root != root->node);
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radix_tree_tag_set(&root->fs_info->fs_roots_radix,
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(unsigned long)root->root_key.objectid,
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BTRFS_ROOT_TRANS_TAG);
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root->last_trans = trans->transid;
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btrfs_init_reloc_root(trans, root);
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}
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return 0;
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}
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int btrfs_record_root_in_trans(struct btrfs_trans_handle *trans,
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struct btrfs_root *root)
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{
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if (!root->ref_cows)
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return 0;
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mutex_lock(&root->fs_info->trans_mutex);
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if (root->last_trans == trans->transid) {
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mutex_unlock(&root->fs_info->trans_mutex);
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return 0;
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}
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record_root_in_trans(trans, root);
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mutex_unlock(&root->fs_info->trans_mutex);
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return 0;
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}
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/* wait for commit against the current transaction to become unblocked
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* when this is done, it is safe to start a new transaction, but the current
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* transaction might not be fully on disk.
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*/
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static void wait_current_trans(struct btrfs_root *root)
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{
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struct btrfs_transaction *cur_trans;
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cur_trans = root->fs_info->running_transaction;
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if (cur_trans && cur_trans->blocked) {
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DEFINE_WAIT(wait);
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cur_trans->use_count++;
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while (1) {
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prepare_to_wait(&root->fs_info->transaction_wait, &wait,
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TASK_UNINTERRUPTIBLE);
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if (cur_trans->blocked) {
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mutex_unlock(&root->fs_info->trans_mutex);
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schedule();
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mutex_lock(&root->fs_info->trans_mutex);
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finish_wait(&root->fs_info->transaction_wait,
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&wait);
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} else {
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finish_wait(&root->fs_info->transaction_wait,
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&wait);
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break;
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}
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}
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put_transaction(cur_trans);
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}
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}
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enum btrfs_trans_type {
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TRANS_START,
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TRANS_JOIN,
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TRANS_USERSPACE,
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};
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static struct btrfs_trans_handle *start_transaction(struct btrfs_root *root,
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int num_blocks, int type)
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{
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struct btrfs_trans_handle *h =
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kmem_cache_alloc(btrfs_trans_handle_cachep, GFP_NOFS);
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int ret;
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mutex_lock(&root->fs_info->trans_mutex);
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if (!root->fs_info->log_root_recovering &&
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((type == TRANS_START && !root->fs_info->open_ioctl_trans) ||
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type == TRANS_USERSPACE))
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wait_current_trans(root);
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ret = join_transaction(root);
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BUG_ON(ret);
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h->transid = root->fs_info->running_transaction->transid;
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h->transaction = root->fs_info->running_transaction;
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h->blocks_reserved = num_blocks;
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h->blocks_used = 0;
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h->block_group = 0;
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h->alloc_exclude_nr = 0;
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h->alloc_exclude_start = 0;
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h->delayed_ref_updates = 0;
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if (!current->journal_info && type != TRANS_USERSPACE)
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current->journal_info = h;
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root->fs_info->running_transaction->use_count++;
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record_root_in_trans(h, root);
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mutex_unlock(&root->fs_info->trans_mutex);
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return h;
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}
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struct btrfs_trans_handle *btrfs_start_transaction(struct btrfs_root *root,
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int num_blocks)
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{
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return start_transaction(root, num_blocks, TRANS_START);
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}
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struct btrfs_trans_handle *btrfs_join_transaction(struct btrfs_root *root,
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int num_blocks)
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{
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return start_transaction(root, num_blocks, TRANS_JOIN);
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}
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struct btrfs_trans_handle *btrfs_start_ioctl_transaction(struct btrfs_root *r,
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int num_blocks)
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{
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return start_transaction(r, num_blocks, TRANS_USERSPACE);
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}
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/* wait for a transaction commit to be fully complete */
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static noinline int wait_for_commit(struct btrfs_root *root,
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struct btrfs_transaction *commit)
|
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{
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DEFINE_WAIT(wait);
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mutex_lock(&root->fs_info->trans_mutex);
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while (!commit->commit_done) {
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prepare_to_wait(&commit->commit_wait, &wait,
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TASK_UNINTERRUPTIBLE);
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if (commit->commit_done)
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break;
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mutex_unlock(&root->fs_info->trans_mutex);
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schedule();
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mutex_lock(&root->fs_info->trans_mutex);
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}
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mutex_unlock(&root->fs_info->trans_mutex);
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finish_wait(&commit->commit_wait, &wait);
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return 0;
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}
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|
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#if 0
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/*
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* rate limit against the drop_snapshot code. This helps to slow down new
|
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* operations if the drop_snapshot code isn't able to keep up.
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*/
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static void throttle_on_drops(struct btrfs_root *root)
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{
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struct btrfs_fs_info *info = root->fs_info;
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int harder_count = 0;
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harder:
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if (atomic_read(&info->throttles)) {
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|
DEFINE_WAIT(wait);
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int thr;
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thr = atomic_read(&info->throttle_gen);
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|
|
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do {
|
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|
prepare_to_wait(&info->transaction_throttle,
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&wait, TASK_UNINTERRUPTIBLE);
|
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|
if (!atomic_read(&info->throttles)) {
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finish_wait(&info->transaction_throttle, &wait);
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break;
|
||
|
}
|
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|
schedule();
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finish_wait(&info->transaction_throttle, &wait);
|
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|
} while (thr == atomic_read(&info->throttle_gen));
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harder_count++;
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|
|
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if (root->fs_info->total_ref_cache_size > 1 * 1024 * 1024 &&
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harder_count < 2)
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goto harder;
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|
|
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if (root->fs_info->total_ref_cache_size > 5 * 1024 * 1024 &&
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harder_count < 10)
|
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goto harder;
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|
|
||
|
if (root->fs_info->total_ref_cache_size > 10 * 1024 * 1024 &&
|
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harder_count < 20)
|
||
|
goto harder;
|
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|
}
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|
}
|
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|
#endif
|
||
|
|
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void btrfs_throttle(struct btrfs_root *root)
|
||
|
{
|
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|
mutex_lock(&root->fs_info->trans_mutex);
|
||
|
if (!root->fs_info->open_ioctl_trans)
|
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|
wait_current_trans(root);
|
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|
mutex_unlock(&root->fs_info->trans_mutex);
|
||
|
}
|
||
|
|
||
|
static int __btrfs_end_transaction(struct btrfs_trans_handle *trans,
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|
struct btrfs_root *root, int throttle)
|
||
|
{
|
||
|
struct btrfs_transaction *cur_trans;
|
||
|
struct btrfs_fs_info *info = root->fs_info;
|
||
|
int count = 0;
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|
|
||
|
while (count < 4) {
|
||
|
unsigned long cur = trans->delayed_ref_updates;
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||
|
trans->delayed_ref_updates = 0;
|
||
|
if (cur &&
|
||
|
trans->transaction->delayed_refs.num_heads_ready > 64) {
|
||
|
trans->delayed_ref_updates = 0;
|
||
|
|
||
|
/*
|
||
|
* do a full flush if the transaction is trying
|
||
|
* to close
|
||
|
*/
|
||
|
if (trans->transaction->delayed_refs.flushing)
|
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|
cur = 0;
|
||
|
btrfs_run_delayed_refs(trans, root, cur);
|
||
|
} else {
|
||
|
break;
|
||
|
}
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|
count++;
|
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|
}
|
||
|
|
||
|
mutex_lock(&info->trans_mutex);
|
||
|
cur_trans = info->running_transaction;
|
||
|
WARN_ON(cur_trans != trans->transaction);
|
||
|
WARN_ON(cur_trans->num_writers < 1);
|
||
|
cur_trans->num_writers--;
|
||
|
|
||
|
if (waitqueue_active(&cur_trans->writer_wait))
|
||
|
wake_up(&cur_trans->writer_wait);
|
||
|
put_transaction(cur_trans);
|
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|
mutex_unlock(&info->trans_mutex);
|
||
|
|
||
|
if (current->journal_info == trans)
|
||
|
current->journal_info = NULL;
|
||
|
memset(trans, 0, sizeof(*trans));
|
||
|
kmem_cache_free(btrfs_trans_handle_cachep, trans);
|
||
|
|
||
|
if (throttle)
|
||
|
btrfs_run_delayed_iputs(root);
|
||
|
|
||
|
return 0;
|
||
|
}
|
||
|
|
||
|
int btrfs_end_transaction(struct btrfs_trans_handle *trans,
|
||
|
struct btrfs_root *root)
|
||
|
{
|
||
|
return __btrfs_end_transaction(trans, root, 0);
|
||
|
}
|
||
|
|
||
|
int btrfs_end_transaction_throttle(struct btrfs_trans_handle *trans,
|
||
|
struct btrfs_root *root)
|
||
|
{
|
||
|
return __btrfs_end_transaction(trans, root, 1);
|
||
|
}
|
||
|
|
||
|
/*
|
||
|
* when btree blocks are allocated, they have some corresponding bits set for
|
||
|
* them in one of two extent_io trees. This is used to make sure all of
|
||
|
* those extents are sent to disk but does not wait on them
|
||
|
*/
|
||
|
int btrfs_write_marked_extents(struct btrfs_root *root,
|
||
|
struct extent_io_tree *dirty_pages, int mark)
|
||
|
{
|
||
|
int ret;
|
||
|
int err = 0;
|
||
|
int werr = 0;
|
||
|
struct page *page;
|
||
|
struct inode *btree_inode = root->fs_info->btree_inode;
|
||
|
u64 start = 0;
|
||
|
u64 end;
|
||
|
unsigned long index;
|
||
|
|
||
|
while (1) {
|
||
|
ret = find_first_extent_bit(dirty_pages, start, &start, &end,
|
||
|
mark);
|
||
|
if (ret)
|
||
|
break;
|
||
|
while (start <= end) {
|
||
|
cond_resched();
|
||
|
|
||
|
index = start >> PAGE_CACHE_SHIFT;
|
||
|
start = (u64)(index + 1) << PAGE_CACHE_SHIFT;
|
||
|
page = find_get_page(btree_inode->i_mapping, index);
|
||
|
if (!page)
|
||
|
continue;
|
||
|
|
||
|
btree_lock_page_hook(page);
|
||
|
if (!page->mapping) {
|
||
|
unlock_page(page);
|
||
|
page_cache_release(page);
|
||
|
continue;
|
||
|
}
|
||
|
|
||
|
if (PageWriteback(page)) {
|
||
|
if (PageDirty(page))
|
||
|
wait_on_page_writeback(page);
|
||
|
else {
|
||
|
unlock_page(page);
|
||
|
page_cache_release(page);
|
||
|
continue;
|
||
|
}
|
||
|
}
|
||
|
err = write_one_page(page, 0);
|
||
|
if (err)
|
||
|
werr = err;
|
||
|
page_cache_release(page);
|
||
|
}
|
||
|
}
|
||
|
if (err)
|
||
|
werr = err;
|
||
|
return werr;
|
||
|
}
|
||
|
|
||
|
/*
|
||
|
* when btree blocks are allocated, they have some corresponding bits set for
|
||
|
* them in one of two extent_io trees. This is used to make sure all of
|
||
|
* those extents are on disk for transaction or log commit. We wait
|
||
|
* on all the pages and clear them from the dirty pages state tree
|
||
|
*/
|
||
|
int btrfs_wait_marked_extents(struct btrfs_root *root,
|
||
|
struct extent_io_tree *dirty_pages, int mark)
|
||
|
{
|
||
|
int ret;
|
||
|
int err = 0;
|
||
|
int werr = 0;
|
||
|
struct page *page;
|
||
|
struct inode *btree_inode = root->fs_info->btree_inode;
|
||
|
u64 start = 0;
|
||
|
u64 end;
|
||
|
unsigned long index;
|
||
|
|
||
|
while (1) {
|
||
|
ret = find_first_extent_bit(dirty_pages, start, &start, &end,
|
||
|
mark);
|
||
|
if (ret)
|
||
|
break;
|
||
|
|
||
|
clear_extent_bits(dirty_pages, start, end, mark, GFP_NOFS);
|
||
|
while (start <= end) {
|
||
|
index = start >> PAGE_CACHE_SHIFT;
|
||
|
start = (u64)(index + 1) << PAGE_CACHE_SHIFT;
|
||
|
page = find_get_page(btree_inode->i_mapping, index);
|
||
|
if (!page)
|
||
|
continue;
|
||
|
if (PageDirty(page)) {
|
||
|
btree_lock_page_hook(page);
|
||
|
wait_on_page_writeback(page);
|
||
|
err = write_one_page(page, 0);
|
||
|
if (err)
|
||
|
werr = err;
|
||
|
}
|
||
|
wait_on_page_writeback(page);
|
||
|
page_cache_release(page);
|
||
|
cond_resched();
|
||
|
}
|
||
|
}
|
||
|
if (err)
|
||
|
werr = err;
|
||
|
return werr;
|
||
|
}
|
||
|
|
||
|
/*
|
||
|
* when btree blocks are allocated, they have some corresponding bits set for
|
||
|
* them in one of two extent_io trees. This is used to make sure all of
|
||
|
* those extents are on disk for transaction or log commit
|
||
|
*/
|
||
|
int btrfs_write_and_wait_marked_extents(struct btrfs_root *root,
|
||
|
struct extent_io_tree *dirty_pages, int mark)
|
||
|
{
|
||
|
int ret;
|
||
|
int ret2;
|
||
|
|
||
|
ret = btrfs_write_marked_extents(root, dirty_pages, mark);
|
||
|
ret2 = btrfs_wait_marked_extents(root, dirty_pages, mark);
|
||
|
return ret || ret2;
|
||
|
}
|
||
|
|
||
|
int btrfs_write_and_wait_transaction(struct btrfs_trans_handle *trans,
|
||
|
struct btrfs_root *root)
|
||
|
{
|
||
|
if (!trans || !trans->transaction) {
|
||
|
struct inode *btree_inode;
|
||
|
btree_inode = root->fs_info->btree_inode;
|
||
|
return filemap_write_and_wait(btree_inode->i_mapping);
|
||
|
}
|
||
|
return btrfs_write_and_wait_marked_extents(root,
|
||
|
&trans->transaction->dirty_pages,
|
||
|
EXTENT_DIRTY);
|
||
|
}
|
||
|
|
||
|
/*
|
||
|
* this is used to update the root pointer in the tree of tree roots.
|
||
|
*
|
||
|
* But, in the case of the extent allocation tree, updating the root
|
||
|
* pointer may allocate blocks which may change the root of the extent
|
||
|
* allocation tree.
|
||
|
*
|
||
|
* So, this loops and repeats and makes sure the cowonly root didn't
|
||
|
* change while the root pointer was being updated in the metadata.
|
||
|
*/
|
||
|
static int update_cowonly_root(struct btrfs_trans_handle *trans,
|
||
|
struct btrfs_root *root)
|
||
|
{
|
||
|
int ret;
|
||
|
u64 old_root_bytenr;
|
||
|
u64 old_root_used;
|
||
|
struct btrfs_root *tree_root = root->fs_info->tree_root;
|
||
|
|
||
|
old_root_used = btrfs_root_used(&root->root_item);
|
||
|
btrfs_write_dirty_block_groups(trans, root);
|
||
|
|
||
|
while (1) {
|
||
|
old_root_bytenr = btrfs_root_bytenr(&root->root_item);
|
||
|
if (old_root_bytenr == root->node->start &&
|
||
|
old_root_used == btrfs_root_used(&root->root_item))
|
||
|
break;
|
||
|
|
||
|
btrfs_set_root_node(&root->root_item, root->node);
|
||
|
ret = btrfs_update_root(trans, tree_root,
|
||
|
&root->root_key,
|
||
|
&root->root_item);
|
||
|
BUG_ON(ret);
|
||
|
|
||
|
old_root_used = btrfs_root_used(&root->root_item);
|
||
|
ret = btrfs_write_dirty_block_groups(trans, root);
|
||
|
BUG_ON(ret);
|
||
|
}
|
||
|
|
||
|
if (root != root->fs_info->extent_root)
|
||
|
switch_commit_root(root);
|
||
|
|
||
|
return 0;
|
||
|
}
|
||
|
|
||
|
/*
|
||
|
* update all the cowonly tree roots on disk
|
||
|
*/
|
||
|
static noinline int commit_cowonly_roots(struct btrfs_trans_handle *trans,
|
||
|
struct btrfs_root *root)
|
||
|
{
|
||
|
struct btrfs_fs_info *fs_info = root->fs_info;
|
||
|
struct list_head *next;
|
||
|
struct extent_buffer *eb;
|
||
|
int ret;
|
||
|
|
||
|
ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1);
|
||
|
BUG_ON(ret);
|
||
|
|
||
|
eb = btrfs_lock_root_node(fs_info->tree_root);
|
||
|
btrfs_cow_block(trans, fs_info->tree_root, eb, NULL, 0, &eb);
|
||
|
btrfs_tree_unlock(eb);
|
||
|
free_extent_buffer(eb);
|
||
|
|
||
|
ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1);
|
||
|
BUG_ON(ret);
|
||
|
|
||
|
while (!list_empty(&fs_info->dirty_cowonly_roots)) {
|
||
|
next = fs_info->dirty_cowonly_roots.next;
|
||
|
list_del_init(next);
|
||
|
root = list_entry(next, struct btrfs_root, dirty_list);
|
||
|
|
||
|
update_cowonly_root(trans, root);
|
||
|
}
|
||
|
|
||
|
down_write(&fs_info->extent_commit_sem);
|
||
|
switch_commit_root(fs_info->extent_root);
|
||
|
up_write(&fs_info->extent_commit_sem);
|
||
|
|
||
|
return 0;
|
||
|
}
|
||
|
|
||
|
/*
|
||
|
* dead roots are old snapshots that need to be deleted. This allocates
|
||
|
* a dirty root struct and adds it into the list of dead roots that need to
|
||
|
* be deleted
|
||
|
*/
|
||
|
int btrfs_add_dead_root(struct btrfs_root *root)
|
||
|
{
|
||
|
mutex_lock(&root->fs_info->trans_mutex);
|
||
|
list_add(&root->root_list, &root->fs_info->dead_roots);
|
||
|
mutex_unlock(&root->fs_info->trans_mutex);
|
||
|
return 0;
|
||
|
}
|
||
|
|
||
|
/*
|
||
|
* update all the cowonly tree roots on disk
|
||
|
*/
|
||
|
static noinline int commit_fs_roots(struct btrfs_trans_handle *trans,
|
||
|
struct btrfs_root *root)
|
||
|
{
|
||
|
struct btrfs_root *gang[8];
|
||
|
struct btrfs_fs_info *fs_info = root->fs_info;
|
||
|
int i;
|
||
|
int ret;
|
||
|
int err = 0;
|
||
|
|
||
|
while (1) {
|
||
|
ret = radix_tree_gang_lookup_tag(&fs_info->fs_roots_radix,
|
||
|
(void **)gang, 0,
|
||
|
ARRAY_SIZE(gang),
|
||
|
BTRFS_ROOT_TRANS_TAG);
|
||
|
if (ret == 0)
|
||
|
break;
|
||
|
for (i = 0; i < ret; i++) {
|
||
|
root = gang[i];
|
||
|
radix_tree_tag_clear(&fs_info->fs_roots_radix,
|
||
|
(unsigned long)root->root_key.objectid,
|
||
|
BTRFS_ROOT_TRANS_TAG);
|
||
|
|
||
|
btrfs_free_log(trans, root);
|
||
|
btrfs_update_reloc_root(trans, root);
|
||
|
|
||
|
if (root->commit_root != root->node) {
|
||
|
switch_commit_root(root);
|
||
|
btrfs_set_root_node(&root->root_item,
|
||
|
root->node);
|
||
|
}
|
||
|
|
||
|
err = btrfs_update_root(trans, fs_info->tree_root,
|
||
|
&root->root_key,
|
||
|
&root->root_item);
|
||
|
if (err)
|
||
|
break;
|
||
|
}
|
||
|
}
|
||
|
return err;
|
||
|
}
|
||
|
|
||
|
/*
|
||
|
* defrag a given btree. If cacheonly == 1, this won't read from the disk,
|
||
|
* otherwise every leaf in the btree is read and defragged.
|
||
|
*/
|
||
|
int btrfs_defrag_root(struct btrfs_root *root, int cacheonly)
|
||
|
{
|
||
|
struct btrfs_fs_info *info = root->fs_info;
|
||
|
int ret;
|
||
|
struct btrfs_trans_handle *trans;
|
||
|
unsigned long nr;
|
||
|
|
||
|
smp_mb();
|
||
|
if (root->defrag_running)
|
||
|
return 0;
|
||
|
trans = btrfs_start_transaction(root, 1);
|
||
|
while (1) {
|
||
|
root->defrag_running = 1;
|
||
|
ret = btrfs_defrag_leaves(trans, root, cacheonly);
|
||
|
nr = trans->blocks_used;
|
||
|
btrfs_end_transaction(trans, root);
|
||
|
btrfs_btree_balance_dirty(info->tree_root, nr);
|
||
|
cond_resched();
|
||
|
|
||
|
trans = btrfs_start_transaction(root, 1);
|
||
|
if (root->fs_info->closing || ret != -EAGAIN)
|
||
|
break;
|
||
|
}
|
||
|
root->defrag_running = 0;
|
||
|
smp_mb();
|
||
|
btrfs_end_transaction(trans, root);
|
||
|
return 0;
|
||
|
}
|
||
|
|
||
|
#if 0
|
||
|
/*
|
||
|
* when dropping snapshots, we generate a ton of delayed refs, and it makes
|
||
|
* sense not to join the transaction while it is trying to flush the current
|
||
|
* queue of delayed refs out.
|
||
|
*
|
||
|
* This is used by the drop snapshot code only
|
||
|
*/
|
||
|
static noinline int wait_transaction_pre_flush(struct btrfs_fs_info *info)
|
||
|
{
|
||
|
DEFINE_WAIT(wait);
|
||
|
|
||
|
mutex_lock(&info->trans_mutex);
|
||
|
while (info->running_transaction &&
|
||
|
info->running_transaction->delayed_refs.flushing) {
|
||
|
prepare_to_wait(&info->transaction_wait, &wait,
|
||
|
TASK_UNINTERRUPTIBLE);
|
||
|
mutex_unlock(&info->trans_mutex);
|
||
|
|
||
|
schedule();
|
||
|
|
||
|
mutex_lock(&info->trans_mutex);
|
||
|
finish_wait(&info->transaction_wait, &wait);
|
||
|
}
|
||
|
mutex_unlock(&info->trans_mutex);
|
||
|
return 0;
|
||
|
}
|
||
|
|
||
|
/*
|
||
|
* Given a list of roots that need to be deleted, call btrfs_drop_snapshot on
|
||
|
* all of them
|
||
|
*/
|
||
|
int btrfs_drop_dead_root(struct btrfs_root *root)
|
||
|
{
|
||
|
struct btrfs_trans_handle *trans;
|
||
|
struct btrfs_root *tree_root = root->fs_info->tree_root;
|
||
|
unsigned long nr;
|
||
|
int ret;
|
||
|
|
||
|
while (1) {
|
||
|
/*
|
||
|
* we don't want to jump in and create a bunch of
|
||
|
* delayed refs if the transaction is starting to close
|
||
|
*/
|
||
|
wait_transaction_pre_flush(tree_root->fs_info);
|
||
|
trans = btrfs_start_transaction(tree_root, 1);
|
||
|
|
||
|
/*
|
||
|
* we've joined a transaction, make sure it isn't
|
||
|
* closing right now
|
||
|
*/
|
||
|
if (trans->transaction->delayed_refs.flushing) {
|
||
|
btrfs_end_transaction(trans, tree_root);
|
||
|
continue;
|
||
|
}
|
||
|
|
||
|
ret = btrfs_drop_snapshot(trans, root);
|
||
|
if (ret != -EAGAIN)
|
||
|
break;
|
||
|
|
||
|
ret = btrfs_update_root(trans, tree_root,
|
||
|
&root->root_key,
|
||
|
&root->root_item);
|
||
|
if (ret)
|
||
|
break;
|
||
|
|
||
|
nr = trans->blocks_used;
|
||
|
ret = btrfs_end_transaction(trans, tree_root);
|
||
|
BUG_ON(ret);
|
||
|
|
||
|
btrfs_btree_balance_dirty(tree_root, nr);
|
||
|
cond_resched();
|
||
|
}
|
||
|
BUG_ON(ret);
|
||
|
|
||
|
ret = btrfs_del_root(trans, tree_root, &root->root_key);
|
||
|
BUG_ON(ret);
|
||
|
|
||
|
nr = trans->blocks_used;
|
||
|
ret = btrfs_end_transaction(trans, tree_root);
|
||
|
BUG_ON(ret);
|
||
|
|
||
|
free_extent_buffer(root->node);
|
||
|
free_extent_buffer(root->commit_root);
|
||
|
kfree(root);
|
||
|
|
||
|
btrfs_btree_balance_dirty(tree_root, nr);
|
||
|
return ret;
|
||
|
}
|
||
|
#endif
|
||
|
|
||
|
/*
|
||
|
* new snapshots need to be created at a very specific time in the
|
||
|
* transaction commit. This does the actual creation
|
||
|
*/
|
||
|
static noinline int create_pending_snapshot(struct btrfs_trans_handle *trans,
|
||
|
struct btrfs_fs_info *fs_info,
|
||
|
struct btrfs_pending_snapshot *pending)
|
||
|
{
|
||
|
struct btrfs_key key;
|
||
|
struct btrfs_root_item *new_root_item;
|
||
|
struct btrfs_root *tree_root = fs_info->tree_root;
|
||
|
struct btrfs_root *root = pending->root;
|
||
|
struct extent_buffer *tmp;
|
||
|
struct extent_buffer *old;
|
||
|
int ret;
|
||
|
u64 objectid;
|
||
|
|
||
|
new_root_item = kmalloc(sizeof(*new_root_item), GFP_NOFS);
|
||
|
if (!new_root_item) {
|
||
|
ret = -ENOMEM;
|
||
|
goto fail;
|
||
|
}
|
||
|
ret = btrfs_find_free_objectid(trans, tree_root, 0, &objectid);
|
||
|
if (ret)
|
||
|
goto fail;
|
||
|
|
||
|
record_root_in_trans(trans, root);
|
||
|
btrfs_set_root_last_snapshot(&root->root_item, trans->transid);
|
||
|
memcpy(new_root_item, &root->root_item, sizeof(*new_root_item));
|
||
|
btrfs_check_and_init_root_item(new_root_item);
|
||
|
|
||
|
key.objectid = objectid;
|
||
|
/* record when the snapshot was created in key.offset */
|
||
|
key.offset = trans->transid;
|
||
|
btrfs_set_key_type(&key, BTRFS_ROOT_ITEM_KEY);
|
||
|
|
||
|
old = btrfs_lock_root_node(root);
|
||
|
btrfs_cow_block(trans, root, old, NULL, 0, &old);
|
||
|
btrfs_set_lock_blocking(old);
|
||
|
|
||
|
btrfs_copy_root(trans, root, old, &tmp, objectid);
|
||
|
btrfs_tree_unlock(old);
|
||
|
free_extent_buffer(old);
|
||
|
|
||
|
btrfs_set_root_node(new_root_item, tmp);
|
||
|
ret = btrfs_insert_root(trans, root->fs_info->tree_root, &key,
|
||
|
new_root_item);
|
||
|
btrfs_tree_unlock(tmp);
|
||
|
free_extent_buffer(tmp);
|
||
|
if (ret)
|
||
|
goto fail;
|
||
|
|
||
|
key.offset = (u64)-1;
|
||
|
memcpy(&pending->root_key, &key, sizeof(key));
|
||
|
fail:
|
||
|
kfree(new_root_item);
|
||
|
return ret;
|
||
|
}
|
||
|
|
||
|
static noinline int finish_pending_snapshot(struct btrfs_fs_info *fs_info,
|
||
|
struct btrfs_pending_snapshot *pending)
|
||
|
{
|
||
|
int ret;
|
||
|
int namelen;
|
||
|
u64 index = 0;
|
||
|
struct btrfs_trans_handle *trans;
|
||
|
struct inode *parent_inode;
|
||
|
struct btrfs_root *parent_root;
|
||
|
|
||
|
parent_inode = pending->dentry->d_parent->d_inode;
|
||
|
parent_root = BTRFS_I(parent_inode)->root;
|
||
|
trans = btrfs_join_transaction(parent_root, 1);
|
||
|
|
||
|
/*
|
||
|
* insert the directory item
|
||
|
*/
|
||
|
namelen = strlen(pending->name);
|
||
|
ret = btrfs_set_inode_index(parent_inode, &index);
|
||
|
ret = btrfs_insert_dir_item(trans, parent_root,
|
||
|
pending->name, namelen,
|
||
|
parent_inode->i_ino,
|
||
|
&pending->root_key, BTRFS_FT_DIR, index);
|
||
|
|
||
|
if (ret)
|
||
|
goto fail;
|
||
|
|
||
|
btrfs_i_size_write(parent_inode, parent_inode->i_size + namelen * 2);
|
||
|
ret = btrfs_update_inode(trans, parent_root, parent_inode);
|
||
|
BUG_ON(ret);
|
||
|
|
||
|
ret = btrfs_add_root_ref(trans, parent_root->fs_info->tree_root,
|
||
|
pending->root_key.objectid,
|
||
|
parent_root->root_key.objectid,
|
||
|
parent_inode->i_ino, index, pending->name,
|
||
|
namelen);
|
||
|
|
||
|
BUG_ON(ret);
|
||
|
|
||
|
fail:
|
||
|
btrfs_end_transaction(trans, fs_info->fs_root);
|
||
|
return ret;
|
||
|
}
|
||
|
|
||
|
/*
|
||
|
* create all the snapshots we've scheduled for creation
|
||
|
*/
|
||
|
static noinline int create_pending_snapshots(struct btrfs_trans_handle *trans,
|
||
|
struct btrfs_fs_info *fs_info)
|
||
|
{
|
||
|
struct btrfs_pending_snapshot *pending;
|
||
|
struct list_head *head = &trans->transaction->pending_snapshots;
|
||
|
int ret;
|
||
|
|
||
|
list_for_each_entry(pending, head, list) {
|
||
|
ret = create_pending_snapshot(trans, fs_info, pending);
|
||
|
BUG_ON(ret);
|
||
|
}
|
||
|
return 0;
|
||
|
}
|
||
|
|
||
|
static noinline int finish_pending_snapshots(struct btrfs_trans_handle *trans,
|
||
|
struct btrfs_fs_info *fs_info)
|
||
|
{
|
||
|
struct btrfs_pending_snapshot *pending;
|
||
|
struct list_head *head = &trans->transaction->pending_snapshots;
|
||
|
int ret;
|
||
|
|
||
|
while (!list_empty(head)) {
|
||
|
pending = list_entry(head->next,
|
||
|
struct btrfs_pending_snapshot, list);
|
||
|
ret = finish_pending_snapshot(fs_info, pending);
|
||
|
BUG_ON(ret);
|
||
|
list_del(&pending->list);
|
||
|
kfree(pending->name);
|
||
|
kfree(pending);
|
||
|
}
|
||
|
return 0;
|
||
|
}
|
||
|
|
||
|
static void update_super_roots(struct btrfs_root *root)
|
||
|
{
|
||
|
struct btrfs_root_item *root_item;
|
||
|
struct btrfs_super_block *super;
|
||
|
|
||
|
super = &root->fs_info->super_copy;
|
||
|
|
||
|
root_item = &root->fs_info->chunk_root->root_item;
|
||
|
super->chunk_root = root_item->bytenr;
|
||
|
super->chunk_root_generation = root_item->generation;
|
||
|
super->chunk_root_level = root_item->level;
|
||
|
|
||
|
root_item = &root->fs_info->tree_root->root_item;
|
||
|
super->root = root_item->bytenr;
|
||
|
super->generation = root_item->generation;
|
||
|
super->root_level = root_item->level;
|
||
|
}
|
||
|
|
||
|
int btrfs_transaction_in_commit(struct btrfs_fs_info *info)
|
||
|
{
|
||
|
int ret = 0;
|
||
|
spin_lock(&info->new_trans_lock);
|
||
|
if (info->running_transaction)
|
||
|
ret = info->running_transaction->in_commit;
|
||
|
spin_unlock(&info->new_trans_lock);
|
||
|
return ret;
|
||
|
}
|
||
|
|
||
|
int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
|
||
|
struct btrfs_root *root)
|
||
|
{
|
||
|
unsigned long joined = 0;
|
||
|
unsigned long timeout = 1;
|
||
|
struct btrfs_transaction *cur_trans;
|
||
|
struct btrfs_transaction *prev_trans = NULL;
|
||
|
DEFINE_WAIT(wait);
|
||
|
int ret;
|
||
|
int should_grow = 0;
|
||
|
unsigned long now = get_seconds();
|
||
|
int flush_on_commit = btrfs_test_opt(root, FLUSHONCOMMIT);
|
||
|
|
||
|
btrfs_run_ordered_operations(root, 0);
|
||
|
|
||
|
/* make a pass through all the delayed refs we have so far
|
||
|
* any runnings procs may add more while we are here
|
||
|
*/
|
||
|
ret = btrfs_run_delayed_refs(trans, root, 0);
|
||
|
BUG_ON(ret);
|
||
|
|
||
|
cur_trans = trans->transaction;
|
||
|
/*
|
||
|
* set the flushing flag so procs in this transaction have to
|
||
|
* start sending their work down.
|
||
|
*/
|
||
|
cur_trans->delayed_refs.flushing = 1;
|
||
|
|
||
|
ret = btrfs_run_delayed_refs(trans, root, 0);
|
||
|
BUG_ON(ret);
|
||
|
|
||
|
mutex_lock(&root->fs_info->trans_mutex);
|
||
|
if (cur_trans->in_commit) {
|
||
|
cur_trans->use_count++;
|
||
|
mutex_unlock(&root->fs_info->trans_mutex);
|
||
|
btrfs_end_transaction(trans, root);
|
||
|
|
||
|
ret = wait_for_commit(root, cur_trans);
|
||
|
BUG_ON(ret);
|
||
|
|
||
|
mutex_lock(&root->fs_info->trans_mutex);
|
||
|
put_transaction(cur_trans);
|
||
|
mutex_unlock(&root->fs_info->trans_mutex);
|
||
|
|
||
|
return 0;
|
||
|
}
|
||
|
|
||
|
trans->transaction->in_commit = 1;
|
||
|
trans->transaction->blocked = 1;
|
||
|
if (cur_trans->list.prev != &root->fs_info->trans_list) {
|
||
|
prev_trans = list_entry(cur_trans->list.prev,
|
||
|
struct btrfs_transaction, list);
|
||
|
if (!prev_trans->commit_done) {
|
||
|
prev_trans->use_count++;
|
||
|
mutex_unlock(&root->fs_info->trans_mutex);
|
||
|
|
||
|
wait_for_commit(root, prev_trans);
|
||
|
|
||
|
mutex_lock(&root->fs_info->trans_mutex);
|
||
|
put_transaction(prev_trans);
|
||
|
}
|
||
|
}
|
||
|
|
||
|
if (now < cur_trans->start_time || now - cur_trans->start_time < 1)
|
||
|
should_grow = 1;
|
||
|
|
||
|
do {
|
||
|
int snap_pending = 0;
|
||
|
joined = cur_trans->num_joined;
|
||
|
if (!list_empty(&trans->transaction->pending_snapshots))
|
||
|
snap_pending = 1;
|
||
|
|
||
|
WARN_ON(cur_trans != trans->transaction);
|
||
|
prepare_to_wait(&cur_trans->writer_wait, &wait,
|
||
|
TASK_UNINTERRUPTIBLE);
|
||
|
|
||
|
if (cur_trans->num_writers > 1)
|
||
|
timeout = MAX_SCHEDULE_TIMEOUT;
|
||
|
else if (should_grow)
|
||
|
timeout = 1;
|
||
|
|
||
|
mutex_unlock(&root->fs_info->trans_mutex);
|
||
|
|
||
|
if (flush_on_commit) {
|
||
|
btrfs_start_delalloc_inodes(root, 1);
|
||
|
ret = btrfs_wait_ordered_extents(root, 0, 1);
|
||
|
BUG_ON(ret);
|
||
|
} else if (snap_pending) {
|
||
|
ret = btrfs_wait_ordered_extents(root, 0, 1);
|
||
|
BUG_ON(ret);
|
||
|
}
|
||
|
|
||
|
/*
|
||
|
* rename don't use btrfs_join_transaction, so, once we
|
||
|
* set the transaction to blocked above, we aren't going
|
||
|
* to get any new ordered operations. We can safely run
|
||
|
* it here and no for sure that nothing new will be added
|
||
|
* to the list
|
||
|
*/
|
||
|
btrfs_run_ordered_operations(root, 1);
|
||
|
|
||
|
smp_mb();
|
||
|
if (cur_trans->num_writers > 1 || should_grow)
|
||
|
schedule_timeout(timeout);
|
||
|
|
||
|
mutex_lock(&root->fs_info->trans_mutex);
|
||
|
finish_wait(&cur_trans->writer_wait, &wait);
|
||
|
} while (cur_trans->num_writers > 1 ||
|
||
|
(should_grow && cur_trans->num_joined != joined));
|
||
|
|
||
|
ret = create_pending_snapshots(trans, root->fs_info);
|
||
|
BUG_ON(ret);
|
||
|
|
||
|
ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1);
|
||
|
BUG_ON(ret);
|
||
|
|
||
|
WARN_ON(cur_trans != trans->transaction);
|
||
|
|
||
|
/* btrfs_commit_tree_roots is responsible for getting the
|
||
|
* various roots consistent with each other. Every pointer
|
||
|
* in the tree of tree roots has to point to the most up to date
|
||
|
* root for every subvolume and other tree. So, we have to keep
|
||
|
* the tree logging code from jumping in and changing any
|
||
|
* of the trees.
|
||
|
*
|
||
|
* At this point in the commit, there can't be any tree-log
|
||
|
* writers, but a little lower down we drop the trans mutex
|
||
|
* and let new people in. By holding the tree_log_mutex
|
||
|
* from now until after the super is written, we avoid races
|
||
|
* with the tree-log code.
|
||
|
*/
|
||
|
mutex_lock(&root->fs_info->tree_log_mutex);
|
||
|
|
||
|
ret = commit_fs_roots(trans, root);
|
||
|
BUG_ON(ret);
|
||
|
|
||
|
/* commit_fs_roots gets rid of all the tree log roots, it is now
|
||
|
* safe to free the root of tree log roots
|
||
|
*/
|
||
|
btrfs_free_log_root_tree(trans, root->fs_info);
|
||
|
|
||
|
ret = commit_cowonly_roots(trans, root);
|
||
|
BUG_ON(ret);
|
||
|
|
||
|
btrfs_prepare_extent_commit(trans, root);
|
||
|
|
||
|
cur_trans = root->fs_info->running_transaction;
|
||
|
spin_lock(&root->fs_info->new_trans_lock);
|
||
|
root->fs_info->running_transaction = NULL;
|
||
|
spin_unlock(&root->fs_info->new_trans_lock);
|
||
|
|
||
|
btrfs_set_root_node(&root->fs_info->tree_root->root_item,
|
||
|
root->fs_info->tree_root->node);
|
||
|
switch_commit_root(root->fs_info->tree_root);
|
||
|
|
||
|
btrfs_set_root_node(&root->fs_info->chunk_root->root_item,
|
||
|
root->fs_info->chunk_root->node);
|
||
|
switch_commit_root(root->fs_info->chunk_root);
|
||
|
|
||
|
update_super_roots(root);
|
||
|
|
||
|
if (!root->fs_info->log_root_recovering) {
|
||
|
btrfs_set_super_log_root(&root->fs_info->super_copy, 0);
|
||
|
btrfs_set_super_log_root_level(&root->fs_info->super_copy, 0);
|
||
|
}
|
||
|
|
||
|
memcpy(&root->fs_info->super_for_commit, &root->fs_info->super_copy,
|
||
|
sizeof(root->fs_info->super_copy));
|
||
|
|
||
|
trans->transaction->blocked = 0;
|
||
|
|
||
|
wake_up(&root->fs_info->transaction_wait);
|
||
|
|
||
|
mutex_unlock(&root->fs_info->trans_mutex);
|
||
|
ret = btrfs_write_and_wait_transaction(trans, root);
|
||
|
BUG_ON(ret);
|
||
|
write_ctree_super(trans, root, 0);
|
||
|
|
||
|
/*
|
||
|
* the super is written, we can safely allow the tree-loggers
|
||
|
* to go about their business
|
||
|
*/
|
||
|
mutex_unlock(&root->fs_info->tree_log_mutex);
|
||
|
|
||
|
btrfs_finish_extent_commit(trans, root);
|
||
|
|
||
|
/* do the directory inserts of any pending snapshot creations */
|
||
|
finish_pending_snapshots(trans, root->fs_info);
|
||
|
|
||
|
mutex_lock(&root->fs_info->trans_mutex);
|
||
|
|
||
|
cur_trans->commit_done = 1;
|
||
|
|
||
|
root->fs_info->last_trans_committed = cur_trans->transid;
|
||
|
|
||
|
wake_up(&cur_trans->commit_wait);
|
||
|
|
||
|
put_transaction(cur_trans);
|
||
|
put_transaction(cur_trans);
|
||
|
|
||
|
mutex_unlock(&root->fs_info->trans_mutex);
|
||
|
|
||
|
if (current->journal_info == trans)
|
||
|
current->journal_info = NULL;
|
||
|
|
||
|
kmem_cache_free(btrfs_trans_handle_cachep, trans);
|
||
|
|
||
|
if (current != root->fs_info->transaction_kthread)
|
||
|
btrfs_run_delayed_iputs(root);
|
||
|
|
||
|
return ret;
|
||
|
}
|
||
|
|
||
|
/*
|
||
|
* interface function to delete all the snapshots we have scheduled for deletion
|
||
|
*/
|
||
|
int btrfs_clean_old_snapshots(struct btrfs_root *root)
|
||
|
{
|
||
|
LIST_HEAD(list);
|
||
|
struct btrfs_fs_info *fs_info = root->fs_info;
|
||
|
|
||
|
mutex_lock(&fs_info->trans_mutex);
|
||
|
list_splice_init(&fs_info->dead_roots, &list);
|
||
|
mutex_unlock(&fs_info->trans_mutex);
|
||
|
|
||
|
while (!list_empty(&list)) {
|
||
|
root = list_entry(list.next, struct btrfs_root, root_list);
|
||
|
list_del(&root->root_list);
|
||
|
|
||
|
if (btrfs_header_backref_rev(root->node) <
|
||
|
BTRFS_MIXED_BACKREF_REV)
|
||
|
btrfs_drop_snapshot(root, 0);
|
||
|
else
|
||
|
btrfs_drop_snapshot(root, 1);
|
||
|
}
|
||
|
return 0;
|
||
|
}
|