![Chris Mason](/assets/img/avatar_default.png)
After a transaction commit, the old root of the subvol btrees are sent through snapshot removal. This is what actually frees up any blocks replaced by COW, and anything the old blocks pointed to. Snapshot deletion will pause when a transaction commit has started, which helps to avoid a huge amount of delayed reference count updates piling up as the transaction is trying to close. But, this pause happens after the snapshot deletion process has asked other procs on the system to throttle back a bit so that it can make progress. We don't want to throttle everyone while we're waiting for the transaction commit, it leads to deadlocks in the user transaction ioctls used by Ceph and makes things slower in general. This patch changes things to avoid the throttling while we sleep. Signed-off-by: Chris Mason <chris.mason@oracle.com>
1220 lines
33 KiB
C
1220 lines
33 KiB
C
/*
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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 "ref-cache.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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/*
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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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noinline int btrfs_record_root_in_trans(struct btrfs_root *root)
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{
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struct btrfs_dirty_root *dirty;
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u64 running_trans_id = root->fs_info->running_transaction->transid;
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if (root->ref_cows && root->last_trans < running_trans_id) {
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WARN_ON(root == root->fs_info->extent_root);
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if (root->root_item.refs != 0) {
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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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dirty = kmalloc(sizeof(*dirty), GFP_NOFS);
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BUG_ON(!dirty);
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dirty->root = kmalloc(sizeof(*dirty->root), GFP_NOFS);
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BUG_ON(!dirty->root);
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dirty->latest_root = root;
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INIT_LIST_HEAD(&dirty->list);
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root->commit_root = btrfs_root_node(root);
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memcpy(dirty->root, root, sizeof(*root));
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spin_lock_init(&dirty->root->node_lock);
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spin_lock_init(&dirty->root->list_lock);
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mutex_init(&dirty->root->objectid_mutex);
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mutex_init(&dirty->root->log_mutex);
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INIT_LIST_HEAD(&dirty->root->dead_list);
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dirty->root->node = root->commit_root;
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dirty->root->commit_root = NULL;
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spin_lock(&root->list_lock);
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list_add(&dirty->root->dead_list, &root->dead_list);
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spin_unlock(&root->list_lock);
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root->dirty_root = dirty;
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} else {
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WARN_ON(1);
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}
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root->last_trans = running_trans_id;
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}
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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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static struct btrfs_trans_handle *start_transaction(struct btrfs_root *root,
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int num_blocks, int wait)
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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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((wait == 1 && !root->fs_info->open_ioctl_trans) || wait == 2))
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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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btrfs_record_root_in_trans(root);
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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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root->fs_info->running_transaction->use_count++;
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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, 1);
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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, 0);
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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, 2);
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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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* 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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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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}
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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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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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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)
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goto harder;
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}
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}
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void btrfs_throttle(struct btrfs_root *root)
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{
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mutex_lock(&root->fs_info->trans_mutex);
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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);
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throttle_on_drops(root);
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}
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static int __btrfs_end_transaction(struct btrfs_trans_handle *trans,
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struct btrfs_root *root, int throttle)
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{
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struct btrfs_transaction *cur_trans;
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struct btrfs_fs_info *info = root->fs_info;
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int count = 0;
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while (count < 4) {
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unsigned long cur = trans->delayed_ref_updates;
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trans->delayed_ref_updates = 0;
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if (cur &&
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trans->transaction->delayed_refs.num_heads_ready > 64) {
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trans->delayed_ref_updates = 0;
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/*
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* do a full flush if the transaction is trying
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* to close
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*/
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if (trans->transaction->delayed_refs.flushing)
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cur = 0;
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btrfs_run_delayed_refs(trans, root, cur);
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} else {
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break;
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}
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count++;
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}
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mutex_lock(&info->trans_mutex);
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cur_trans = info->running_transaction;
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WARN_ON(cur_trans != trans->transaction);
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WARN_ON(cur_trans->num_writers < 1);
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cur_trans->num_writers--;
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if (waitqueue_active(&cur_trans->writer_wait))
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wake_up(&cur_trans->writer_wait);
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put_transaction(cur_trans);
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mutex_unlock(&info->trans_mutex);
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memset(trans, 0, sizeof(*trans));
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kmem_cache_free(btrfs_trans_handle_cachep, trans);
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if (throttle)
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throttle_on_drops(root);
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return 0;
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}
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int btrfs_end_transaction(struct btrfs_trans_handle *trans,
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struct btrfs_root *root)
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{
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return __btrfs_end_transaction(trans, root, 0);
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}
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int btrfs_end_transaction_throttle(struct btrfs_trans_handle *trans,
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struct btrfs_root *root)
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{
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return __btrfs_end_transaction(trans, root, 1);
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}
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/*
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* when btree blocks are allocated, they have some corresponding bits set for
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* them in one of two extent_io trees. This is used to make sure all of
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* those extents are on disk for transaction or log commit
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*/
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int btrfs_write_and_wait_marked_extents(struct btrfs_root *root,
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struct extent_io_tree *dirty_pages)
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{
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int ret;
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int err = 0;
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int werr = 0;
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struct page *page;
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struct inode *btree_inode = root->fs_info->btree_inode;
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u64 start = 0;
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u64 end;
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unsigned long index;
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while (1) {
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ret = find_first_extent_bit(dirty_pages, start, &start, &end,
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EXTENT_DIRTY);
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if (ret)
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break;
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while (start <= end) {
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cond_resched();
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index = start >> PAGE_CACHE_SHIFT;
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start = (u64)(index + 1) << PAGE_CACHE_SHIFT;
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page = find_get_page(btree_inode->i_mapping, index);
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if (!page)
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continue;
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btree_lock_page_hook(page);
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if (!page->mapping) {
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unlock_page(page);
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page_cache_release(page);
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continue;
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}
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if (PageWriteback(page)) {
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if (PageDirty(page))
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wait_on_page_writeback(page);
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else {
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unlock_page(page);
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page_cache_release(page);
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continue;
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}
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}
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err = write_one_page(page, 0);
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if (err)
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werr = err;
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page_cache_release(page);
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}
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}
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while (1) {
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ret = find_first_extent_bit(dirty_pages, 0, &start, &end,
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EXTENT_DIRTY);
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if (ret)
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break;
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clear_extent_dirty(dirty_pages, start, end, GFP_NOFS);
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while (start <= end) {
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index = start >> PAGE_CACHE_SHIFT;
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start = (u64)(index + 1) << PAGE_CACHE_SHIFT;
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page = find_get_page(btree_inode->i_mapping, index);
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if (!page)
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continue;
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if (PageDirty(page)) {
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btree_lock_page_hook(page);
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wait_on_page_writeback(page);
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err = write_one_page(page, 0);
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if (err)
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werr = err;
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}
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wait_on_page_writeback(page);
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page_cache_release(page);
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cond_resched();
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}
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}
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if (err)
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werr = err;
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return werr;
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}
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int btrfs_write_and_wait_transaction(struct btrfs_trans_handle *trans,
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struct btrfs_root *root)
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{
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if (!trans || !trans->transaction) {
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struct inode *btree_inode;
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btree_inode = root->fs_info->btree_inode;
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return filemap_write_and_wait(btree_inode->i_mapping);
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}
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return btrfs_write_and_wait_marked_extents(root,
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&trans->transaction->dirty_pages);
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}
|
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/*
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* this is used to update the root pointer in the tree of tree roots.
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*
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* But, in the case of the extent allocation tree, updating the root
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* pointer may allocate blocks which may change the root of the extent
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* allocation tree.
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*
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* So, this loops and repeats and makes sure the cowonly root didn't
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* change while the root pointer was being updated in the metadata.
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*/
|
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static int update_cowonly_root(struct btrfs_trans_handle *trans,
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struct btrfs_root *root)
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{
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int ret;
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u64 old_root_bytenr;
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struct btrfs_root *tree_root = root->fs_info->tree_root;
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|
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btrfs_write_dirty_block_groups(trans, root);
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|
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ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1);
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BUG_ON(ret);
|
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|
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while (1) {
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old_root_bytenr = btrfs_root_bytenr(&root->root_item);
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if (old_root_bytenr == root->node->start)
|
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break;
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btrfs_set_root_bytenr(&root->root_item,
|
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root->node->start);
|
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btrfs_set_root_level(&root->root_item,
|
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btrfs_header_level(root->node));
|
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btrfs_set_root_generation(&root->root_item, trans->transid);
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|
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ret = btrfs_update_root(trans, tree_root,
|
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&root->root_key,
|
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&root->root_item);
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BUG_ON(ret);
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btrfs_write_dirty_block_groups(trans, root);
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ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1);
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BUG_ON(ret);
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}
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return 0;
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}
|
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|
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/*
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* update all the cowonly tree roots on disk
|
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*/
|
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int btrfs_commit_tree_roots(struct btrfs_trans_handle *trans,
|
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struct btrfs_root *root)
|
|
{
|
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struct btrfs_fs_info *fs_info = root->fs_info;
|
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struct list_head *next;
|
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struct extent_buffer *eb;
|
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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);
|
|
|
|
ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1);
|
|
BUG_ON(ret);
|
|
}
|
|
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, struct btrfs_root *latest)
|
|
{
|
|
struct btrfs_dirty_root *dirty;
|
|
|
|
dirty = kmalloc(sizeof(*dirty), GFP_NOFS);
|
|
if (!dirty)
|
|
return -ENOMEM;
|
|
dirty->root = root;
|
|
dirty->latest_root = latest;
|
|
|
|
mutex_lock(&root->fs_info->trans_mutex);
|
|
list_add(&dirty->list, &latest->fs_info->dead_roots);
|
|
mutex_unlock(&root->fs_info->trans_mutex);
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* at transaction commit time we need to schedule the old roots for
|
|
* deletion via btrfs_drop_snapshot. This runs through all the
|
|
* reference counted roots that were modified in the current
|
|
* transaction and puts them into the drop list
|
|
*/
|
|
static noinline int add_dirty_roots(struct btrfs_trans_handle *trans,
|
|
struct radix_tree_root *radix,
|
|
struct list_head *list)
|
|
{
|
|
struct btrfs_dirty_root *dirty;
|
|
struct btrfs_root *gang[8];
|
|
struct btrfs_root *root;
|
|
int i;
|
|
int ret;
|
|
int err = 0;
|
|
u32 refs;
|
|
|
|
while (1) {
|
|
ret = radix_tree_gang_lookup_tag(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(radix,
|
|
(unsigned long)root->root_key.objectid,
|
|
BTRFS_ROOT_TRANS_TAG);
|
|
|
|
BUG_ON(!root->ref_tree);
|
|
dirty = root->dirty_root;
|
|
|
|
btrfs_free_log(trans, root);
|
|
btrfs_free_reloc_root(trans, root);
|
|
|
|
if (root->commit_root == root->node) {
|
|
WARN_ON(root->node->start !=
|
|
btrfs_root_bytenr(&root->root_item));
|
|
|
|
free_extent_buffer(root->commit_root);
|
|
root->commit_root = NULL;
|
|
root->dirty_root = NULL;
|
|
|
|
spin_lock(&root->list_lock);
|
|
list_del_init(&dirty->root->dead_list);
|
|
spin_unlock(&root->list_lock);
|
|
|
|
kfree(dirty->root);
|
|
kfree(dirty);
|
|
|
|
/* make sure to update the root on disk
|
|
* so we get any updates to the block used
|
|
* counts
|
|
*/
|
|
err = btrfs_update_root(trans,
|
|
root->fs_info->tree_root,
|
|
&root->root_key,
|
|
&root->root_item);
|
|
continue;
|
|
}
|
|
|
|
memset(&root->root_item.drop_progress, 0,
|
|
sizeof(struct btrfs_disk_key));
|
|
root->root_item.drop_level = 0;
|
|
root->commit_root = NULL;
|
|
root->dirty_root = NULL;
|
|
root->root_key.offset = root->fs_info->generation;
|
|
btrfs_set_root_bytenr(&root->root_item,
|
|
root->node->start);
|
|
btrfs_set_root_level(&root->root_item,
|
|
btrfs_header_level(root->node));
|
|
btrfs_set_root_generation(&root->root_item,
|
|
root->root_key.offset);
|
|
|
|
err = btrfs_insert_root(trans, root->fs_info->tree_root,
|
|
&root->root_key,
|
|
&root->root_item);
|
|
if (err)
|
|
break;
|
|
|
|
refs = btrfs_root_refs(&dirty->root->root_item);
|
|
btrfs_set_root_refs(&dirty->root->root_item, refs - 1);
|
|
err = btrfs_update_root(trans, root->fs_info->tree_root,
|
|
&dirty->root->root_key,
|
|
&dirty->root->root_item);
|
|
|
|
BUG_ON(err);
|
|
if (refs == 1) {
|
|
list_add(&dirty->list, list);
|
|
} else {
|
|
WARN_ON(1);
|
|
free_extent_buffer(dirty->root->node);
|
|
kfree(dirty->root);
|
|
kfree(dirty);
|
|
}
|
|
}
|
|
}
|
|
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;
|
|
}
|
|
|
|
/*
|
|
* 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);
|
|
|
|
atomic_dec(&info->throttles);
|
|
wake_up(&info->transaction_throttle);
|
|
|
|
schedule();
|
|
|
|
atomic_inc(&info->throttles);
|
|
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
|
|
*/
|
|
static noinline int drop_dirty_roots(struct btrfs_root *tree_root,
|
|
struct list_head *list)
|
|
{
|
|
struct btrfs_dirty_root *dirty;
|
|
struct btrfs_trans_handle *trans;
|
|
unsigned long nr;
|
|
u64 num_bytes;
|
|
u64 bytes_used;
|
|
u64 max_useless;
|
|
int ret = 0;
|
|
int err;
|
|
|
|
while (!list_empty(list)) {
|
|
struct btrfs_root *root;
|
|
|
|
dirty = list_entry(list->prev, struct btrfs_dirty_root, list);
|
|
list_del_init(&dirty->list);
|
|
|
|
num_bytes = btrfs_root_used(&dirty->root->root_item);
|
|
root = dirty->latest_root;
|
|
atomic_inc(&root->fs_info->throttles);
|
|
|
|
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;
|
|
}
|
|
|
|
mutex_lock(&root->fs_info->drop_mutex);
|
|
ret = btrfs_drop_snapshot(trans, dirty->root);
|
|
if (ret != -EAGAIN)
|
|
break;
|
|
mutex_unlock(&root->fs_info->drop_mutex);
|
|
|
|
err = btrfs_update_root(trans,
|
|
tree_root,
|
|
&dirty->root->root_key,
|
|
&dirty->root->root_item);
|
|
if (err)
|
|
ret = err;
|
|
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);
|
|
atomic_dec(&root->fs_info->throttles);
|
|
wake_up(&root->fs_info->transaction_throttle);
|
|
|
|
num_bytes -= btrfs_root_used(&dirty->root->root_item);
|
|
bytes_used = btrfs_root_used(&root->root_item);
|
|
if (num_bytes) {
|
|
mutex_lock(&root->fs_info->trans_mutex);
|
|
btrfs_record_root_in_trans(root);
|
|
mutex_unlock(&root->fs_info->trans_mutex);
|
|
btrfs_set_root_used(&root->root_item,
|
|
bytes_used - num_bytes);
|
|
}
|
|
|
|
ret = btrfs_del_root(trans, tree_root, &dirty->root->root_key);
|
|
if (ret) {
|
|
BUG();
|
|
break;
|
|
}
|
|
mutex_unlock(&root->fs_info->drop_mutex);
|
|
|
|
spin_lock(&root->list_lock);
|
|
list_del_init(&dirty->root->dead_list);
|
|
if (!list_empty(&root->dead_list)) {
|
|
struct btrfs_root *oldest;
|
|
oldest = list_entry(root->dead_list.prev,
|
|
struct btrfs_root, dead_list);
|
|
max_useless = oldest->root_key.offset - 1;
|
|
} else {
|
|
max_useless = root->root_key.offset - 1;
|
|
}
|
|
spin_unlock(&root->list_lock);
|
|
|
|
nr = trans->blocks_used;
|
|
ret = btrfs_end_transaction(trans, tree_root);
|
|
BUG_ON(ret);
|
|
|
|
ret = btrfs_remove_leaf_refs(root, max_useless, 0);
|
|
BUG_ON(ret);
|
|
|
|
free_extent_buffer(dirty->root->node);
|
|
kfree(dirty->root);
|
|
kfree(dirty);
|
|
|
|
btrfs_btree_balance_dirty(tree_root, nr);
|
|
cond_resched();
|
|
}
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* 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;
|
|
|
|
btrfs_record_root_in_trans(root);
|
|
btrfs_set_root_last_snapshot(&root->root_item, trans->transid);
|
|
memcpy(new_root_item, &root->root_item, sizeof(*new_root_item));
|
|
|
|
key.objectid = objectid;
|
|
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_copy_root(trans, root, old, &tmp, objectid);
|
|
btrfs_tree_unlock(old);
|
|
free_extent_buffer(old);
|
|
|
|
btrfs_set_root_bytenr(new_root_item, tmp->start);
|
|
btrfs_set_root_level(new_root_item, btrfs_header_level(tmp));
|
|
btrfs_set_root_generation(new_root_item, trans->transid);
|
|
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 inode *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);
|
|
|
|
/* add the backref first */
|
|
ret = btrfs_add_root_ref(trans, parent_root->fs_info->tree_root,
|
|
pending->root_key.objectid,
|
|
BTRFS_ROOT_BACKREF_KEY,
|
|
parent_root->root_key.objectid,
|
|
parent_inode->i_ino, index, pending->name,
|
|
namelen);
|
|
|
|
BUG_ON(ret);
|
|
|
|
/* now add the forward ref */
|
|
ret = btrfs_add_root_ref(trans, parent_root->fs_info->tree_root,
|
|
parent_root->root_key.objectid,
|
|
BTRFS_ROOT_REF_KEY,
|
|
pending->root_key.objectid,
|
|
parent_inode->i_ino, index, pending->name,
|
|
namelen);
|
|
|
|
inode = btrfs_lookup_dentry(parent_inode, pending->dentry);
|
|
d_instantiate(pending->dentry, inode);
|
|
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;
|
|
}
|
|
|
|
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;
|
|
struct btrfs_root *chunk_root = root->fs_info->chunk_root;
|
|
struct list_head dirty_fs_roots;
|
|
struct extent_io_tree *pinned_copy;
|
|
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);
|
|
INIT_LIST_HEAD(&dirty_fs_roots);
|
|
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;
|
|
}
|
|
|
|
pinned_copy = kmalloc(sizeof(*pinned_copy), GFP_NOFS);
|
|
if (!pinned_copy)
|
|
return -ENOMEM;
|
|
|
|
extent_io_tree_init(pinned_copy,
|
|
root->fs_info->btree_inode->i_mapping, GFP_NOFS);
|
|
|
|
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 || snap_pending) {
|
|
if (flush_on_commit)
|
|
btrfs_start_delalloc_inodes(root);
|
|
ret = btrfs_wait_ordered_extents(root, 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);
|
|
/*
|
|
* keep tree reloc code from adding new reloc trees
|
|
*/
|
|
mutex_lock(&root->fs_info->tree_reloc_mutex);
|
|
|
|
|
|
ret = add_dirty_roots(trans, &root->fs_info->fs_roots_radix,
|
|
&dirty_fs_roots);
|
|
BUG_ON(ret);
|
|
|
|
/* add_dirty_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 = btrfs_commit_tree_roots(trans, root);
|
|
BUG_ON(ret);
|
|
|
|
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_super_generation(&root->fs_info->super_copy,
|
|
cur_trans->transid);
|
|
btrfs_set_super_root(&root->fs_info->super_copy,
|
|
root->fs_info->tree_root->node->start);
|
|
btrfs_set_super_root_level(&root->fs_info->super_copy,
|
|
btrfs_header_level(root->fs_info->tree_root->node));
|
|
|
|
btrfs_set_super_chunk_root(&root->fs_info->super_copy,
|
|
chunk_root->node->start);
|
|
btrfs_set_super_chunk_root_level(&root->fs_info->super_copy,
|
|
btrfs_header_level(chunk_root->node));
|
|
btrfs_set_super_chunk_root_generation(&root->fs_info->super_copy,
|
|
btrfs_header_generation(chunk_root->node));
|
|
|
|
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));
|
|
|
|
btrfs_copy_pinned(root, pinned_copy);
|
|
|
|
trans->transaction->blocked = 0;
|
|
|
|
wake_up(&root->fs_info->transaction_throttle);
|
|
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, pinned_copy);
|
|
kfree(pinned_copy);
|
|
|
|
btrfs_drop_dead_reloc_roots(root);
|
|
mutex_unlock(&root->fs_info->tree_reloc_mutex);
|
|
|
|
/* 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);
|
|
|
|
list_splice_init(&dirty_fs_roots, &root->fs_info->dead_roots);
|
|
if (root->fs_info->closing)
|
|
list_splice_init(&root->fs_info->dead_roots, &dirty_fs_roots);
|
|
|
|
mutex_unlock(&root->fs_info->trans_mutex);
|
|
|
|
kmem_cache_free(btrfs_trans_handle_cachep, trans);
|
|
|
|
if (root->fs_info->closing)
|
|
drop_dirty_roots(root->fs_info->tree_root, &dirty_fs_roots);
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* interface function to delete all the snapshots we have scheduled for deletion
|
|
*/
|
|
int btrfs_clean_old_snapshots(struct btrfs_root *root)
|
|
{
|
|
struct list_head dirty_roots;
|
|
INIT_LIST_HEAD(&dirty_roots);
|
|
again:
|
|
mutex_lock(&root->fs_info->trans_mutex);
|
|
list_splice_init(&root->fs_info->dead_roots, &dirty_roots);
|
|
mutex_unlock(&root->fs_info->trans_mutex);
|
|
|
|
if (!list_empty(&dirty_roots)) {
|
|
drop_dirty_roots(root, &dirty_roots);
|
|
goto again;
|
|
}
|
|
return 0;
|
|
}
|