transaction.c 47.8 KB
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/*
 * Copyright (C) 2007 Oracle.  All rights reserved.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public
 * License v2 as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public
 * License along with this program; if not, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 021110-1307, USA.
 */

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#include <linux/fs.h>
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#include <linux/slab.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 <linux/uuid.h>
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#include "ctree.h"
#include "disk-io.h"
#include "transaction.h"
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#include "locking.h"
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#include "tree-log.h"
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#include "inode-map.h"
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#include "volumes.h"
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#include "dev-replace.h"
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#define BTRFS_ROOT_TRANS_TAG 0

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void put_transaction(struct btrfs_transaction *transaction)
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{
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	WARN_ON(atomic_read(&transaction->use_count) == 0);
	if (atomic_dec_and_test(&transaction->use_count)) {
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		BUG_ON(!list_empty(&transaction->list));
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		WARN_ON(transaction->delayed_refs.root.rb_node);
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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)
{
	free_extent_buffer(root->commit_root);
	root->commit_root = btrfs_root_node(root);
}

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/*
 * either allocate a new transaction or hop into the existing one
 */
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static noinline int join_transaction(struct btrfs_root *root, int type)
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{
	struct btrfs_transaction *cur_trans;
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	struct btrfs_fs_info *fs_info = root->fs_info;
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	spin_lock(&fs_info->trans_lock);
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loop:
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	/* The file system has been taken offline. No new transactions. */
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	if (fs_info->fs_state & BTRFS_SUPER_FLAG_ERROR) {
		spin_unlock(&fs_info->trans_lock);
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		return -EROFS;
	}

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	if (fs_info->trans_no_join) {
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		/* 
		 * If we are JOIN_NOLOCK we're already committing a current
		 * transaction, we just need a handle to deal with something
		 * when committing the transaction, such as inode cache and
		 * space cache. It is a special case.
		 */
		if (type != TRANS_JOIN_NOLOCK) {
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			spin_unlock(&fs_info->trans_lock);
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			return -EBUSY;
		}
	}

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	cur_trans = fs_info->running_transaction;
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	if (cur_trans) {
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		if (cur_trans->aborted) {
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			spin_unlock(&fs_info->trans_lock);
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			return cur_trans->aborted;
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		}
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		atomic_inc(&cur_trans->use_count);
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		atomic_inc(&cur_trans->num_writers);
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		cur_trans->num_joined++;
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		spin_unlock(&fs_info->trans_lock);
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		return 0;
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	}
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	spin_unlock(&fs_info->trans_lock);
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	/*
	 * If we are ATTACH, we just want to catch the current transaction,
	 * and commit it. If there is no transaction, just return ENOENT.
	 */
	if (type == TRANS_ATTACH)
		return -ENOENT;

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	cur_trans = kmem_cache_alloc(btrfs_transaction_cachep, GFP_NOFS);
	if (!cur_trans)
		return -ENOMEM;
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	spin_lock(&fs_info->trans_lock);
	if (fs_info->running_transaction) {
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		/*
		 * someone started a transaction after we unlocked.  Make sure
		 * to redo the trans_no_join checks above
		 */
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		kmem_cache_free(btrfs_transaction_cachep, cur_trans);
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		cur_trans = fs_info->running_transaction;
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		goto loop;
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	} else if (fs_info->fs_state & BTRFS_SUPER_FLAG_ERROR) {
		spin_unlock(&fs_info->trans_lock);
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		kmem_cache_free(btrfs_transaction_cachep, cur_trans);
		return -EROFS;
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	}
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	atomic_set(&cur_trans->num_writers, 1);
	cur_trans->num_joined = 0;
	init_waitqueue_head(&cur_trans->writer_wait);
	init_waitqueue_head(&cur_trans->commit_wait);
	cur_trans->in_commit = 0;
	cur_trans->blocked = 0;
	/*
	 * One for this trans handle, one so it will live on until we
	 * commit the transaction.
	 */
	atomic_set(&cur_trans->use_count, 2);
	cur_trans->commit_done = 0;
	cur_trans->start_time = get_seconds();

	cur_trans->delayed_refs.root = RB_ROOT;
	cur_trans->delayed_refs.num_entries = 0;
	cur_trans->delayed_refs.num_heads_ready = 0;
	cur_trans->delayed_refs.num_heads = 0;
	cur_trans->delayed_refs.flushing = 0;
	cur_trans->delayed_refs.run_delayed_start = 0;
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	/*
	 * although the tree mod log is per file system and not per transaction,
	 * the log must never go across transaction boundaries.
	 */
	smp_mb();
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	if (!list_empty(&fs_info->tree_mod_seq_list))
		WARN(1, KERN_ERR "btrfs: tree_mod_seq_list not empty when "
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			"creating a fresh transaction\n");
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	if (!RB_EMPTY_ROOT(&fs_info->tree_mod_log))
		WARN(1, KERN_ERR "btrfs: tree_mod_log rb tree not empty when "
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			"creating a fresh transaction\n");
	atomic_set(&fs_info->tree_mod_seq, 0);

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	spin_lock_init(&cur_trans->commit_lock);
	spin_lock_init(&cur_trans->delayed_refs.lock);

	INIT_LIST_HEAD(&cur_trans->pending_snapshots);
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	list_add_tail(&cur_trans->list, &fs_info->trans_list);
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	extent_io_tree_init(&cur_trans->dirty_pages,
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			     fs_info->btree_inode->i_mapping);
	fs_info->generation++;
	cur_trans->transid = fs_info->generation;
	fs_info->running_transaction = cur_trans;
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	cur_trans->aborted = 0;
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	spin_unlock(&fs_info->trans_lock);
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	return 0;
}

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/*
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 * this does all the record keeping required to make sure that a reference
 * counted root is properly recorded in a given transaction.  This is required
 * to make sure the old root from before we joined the transaction is deleted
 * when the transaction commits
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 */
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static 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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		/*
		 * see below for in_trans_setup usage rules
		 * we have the reloc mutex held now, so there
		 * is only one writer in this function
		 */
		root->in_trans_setup = 1;

		/* make sure readers find in_trans_setup before
		 * they find our root->last_trans update
		 */
		smp_wmb();

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		spin_lock(&root->fs_info->fs_roots_radix_lock);
		if (root->last_trans == trans->transid) {
			spin_unlock(&root->fs_info->fs_roots_radix_lock);
			return 0;
		}
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		radix_tree_tag_set(&root->fs_info->fs_roots_radix,
			   (unsigned long)root->root_key.objectid,
			   BTRFS_ROOT_TRANS_TAG);
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		spin_unlock(&root->fs_info->fs_roots_radix_lock);
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		root->last_trans = trans->transid;

		/* this is pretty tricky.  We don't want to
		 * take the relocation lock in btrfs_record_root_in_trans
		 * unless we're really doing the first setup for this root in
		 * this transaction.
		 *
		 * Normally we'd use root->last_trans as a flag to decide
		 * if we want to take the expensive mutex.
		 *
		 * But, we have to set root->last_trans before we
		 * init the relocation root, otherwise, we trip over warnings
		 * in ctree.c.  The solution used here is to flag ourselves
		 * with root->in_trans_setup.  When this is 1, we're still
		 * fixing up the reloc trees and everyone must wait.
		 *
		 * When this is zero, they can trust root->last_trans and fly
		 * through btrfs_record_root_in_trans without having to take the
		 * lock.  smp_wmb() makes sure that all the writes above are
		 * done before we pop in the zero below
		 */
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		btrfs_init_reloc_root(trans, root);
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		smp_wmb();
		root->in_trans_setup = 0;
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	}
	return 0;
}
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int btrfs_record_root_in_trans(struct btrfs_trans_handle *trans,
			       struct btrfs_root *root)
{
	if (!root->ref_cows)
		return 0;

	/*
	 * see record_root_in_trans for comments about in_trans_setup usage
	 * and barriers
	 */
	smp_rmb();
	if (root->last_trans == trans->transid &&
	    !root->in_trans_setup)
		return 0;

	mutex_lock(&root->fs_info->reloc_mutex);
	record_root_in_trans(trans, root);
	mutex_unlock(&root->fs_info->reloc_mutex);

	return 0;
}

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/* wait for commit against the current transaction to become unblocked
 * when this is done, it is safe to start a new transaction, but the current
 * transaction might not be fully on disk.
 */
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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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	spin_lock(&root->fs_info->trans_lock);
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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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		atomic_inc(&cur_trans->use_count);
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		spin_unlock(&root->fs_info->trans_lock);
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		wait_event(root->fs_info->transaction_wait,
			   !cur_trans->blocked);
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		put_transaction(cur_trans);
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	} else {
		spin_unlock(&root->fs_info->trans_lock);
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	}
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}

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static int may_wait_transaction(struct btrfs_root *root, int type)
{
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	if (root->fs_info->log_root_recovering)
		return 0;

	if (type == TRANS_USERSPACE)
		return 1;

	if (type == TRANS_START &&
	    !atomic_read(&root->fs_info->open_ioctl_trans))
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		return 1;
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	return 0;
}

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static struct btrfs_trans_handle *
start_transaction(struct btrfs_root *root, u64 num_items, int type,
		  enum btrfs_reserve_flush_enum flush)
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{
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	struct btrfs_trans_handle *h;
	struct btrfs_transaction *cur_trans;
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	u64 num_bytes = 0;
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	int ret;
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	u64 qgroup_reserved = 0;
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	if (root->fs_info->fs_state & BTRFS_SUPER_FLAG_ERROR)
		return ERR_PTR(-EROFS);
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	if (current->journal_info) {
		WARN_ON(type != TRANS_JOIN && type != TRANS_JOIN_NOLOCK);
		h = current->journal_info;
		h->use_count++;
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		WARN_ON(h->use_count > 2);
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		h->orig_rsv = h->block_rsv;
		h->block_rsv = NULL;
		goto got_it;
	}
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	/*
	 * Do the reservation before we join the transaction so we can do all
	 * the appropriate flushing if need be.
	 */
	if (num_items > 0 && root != root->fs_info->chunk_root) {
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		if (root->fs_info->quota_enabled &&
		    is_fstree(root->root_key.objectid)) {
			qgroup_reserved = num_items * root->leafsize;
			ret = btrfs_qgroup_reserve(root, qgroup_reserved);
			if (ret)
				return ERR_PTR(ret);
		}

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		num_bytes = btrfs_calc_trans_metadata_size(root, num_items);
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		ret = btrfs_block_rsv_add(root,
					  &root->fs_info->trans_block_rsv,
					  num_bytes, flush);
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		if (ret)
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			goto reserve_fail;
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	}
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again:
	h = kmem_cache_alloc(btrfs_trans_handle_cachep, GFP_NOFS);
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	if (!h) {
		ret = -ENOMEM;
		goto alloc_fail;
	}
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	/*
	 * If we are JOIN_NOLOCK we're already committing a transaction and
	 * waiting on this guy, so we don't need to do the sb_start_intwrite
	 * because we're already holding a ref.  We need this because we could
	 * have raced in and did an fsync() on a file which can kick a commit
	 * and then we deadlock with somebody doing a freeze.
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	 *
	 * If we are ATTACH, it means we just want to catch the current
	 * transaction and commit it, so we needn't do sb_start_intwrite(). 
353
	 */
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	if (type < TRANS_JOIN_NOLOCK)
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		sb_start_intwrite(root->fs_info->sb);
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357
	if (may_wait_transaction(root, type))
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		wait_current_trans(root);
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	do {
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		ret = join_transaction(root, type);
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		if (ret == -EBUSY)
			wait_current_trans(root);
	} while (ret == -EBUSY);

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	if (ret < 0) {
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		/* We must get the transaction if we are JOIN_NOLOCK. */
		BUG_ON(type == TRANS_JOIN_NOLOCK);
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		goto join_fail;
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	}
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	cur_trans = root->fs_info->running_transaction;

	h->transid = cur_trans->transid;
	h->transaction = cur_trans;
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	h->blocks_used = 0;
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	h->bytes_reserved = 0;
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	h->root = root;
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	h->delayed_ref_updates = 0;
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	h->use_count = 1;
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	h->adding_csums = 0;
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	h->block_rsv = NULL;
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	h->orig_rsv = NULL;
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	h->aborted = 0;
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	h->qgroup_reserved = qgroup_reserved;
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	h->delayed_ref_elem.seq = 0;
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	h->type = type;
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	h->allocating_chunk = false;
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	INIT_LIST_HEAD(&h->qgroup_ref_list);
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	INIT_LIST_HEAD(&h->new_bgs);
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	smp_mb();
	if (cur_trans->blocked && may_wait_transaction(root, type)) {
		btrfs_commit_transaction(h, root);
		goto again;
	}

398
	if (num_bytes) {
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		trace_btrfs_space_reservation(root->fs_info, "transaction",
400
					      h->transid, num_bytes, 1);
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		h->block_rsv = &root->fs_info->trans_block_rsv;
		h->bytes_reserved = num_bytes;
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	}
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got_it:
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	btrfs_record_root_in_trans(h, root);
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	if (!current->journal_info && type != TRANS_USERSPACE)
		current->journal_info = h;
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	return h;
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join_fail:
	if (type < TRANS_JOIN_NOLOCK)
		sb_end_intwrite(root->fs_info->sb);
	kmem_cache_free(btrfs_trans_handle_cachep, h);
alloc_fail:
	if (num_bytes)
		btrfs_block_rsv_release(root, &root->fs_info->trans_block_rsv,
					num_bytes);
reserve_fail:
	if (qgroup_reserved)
		btrfs_qgroup_free(root, qgroup_reserved);
	return ERR_PTR(ret);
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}

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struct btrfs_trans_handle *btrfs_start_transaction(struct btrfs_root *root,
427
						   int num_items)
428
{
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	return start_transaction(root, num_items, TRANS_START,
				 BTRFS_RESERVE_FLUSH_ALL);
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}
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struct btrfs_trans_handle *btrfs_start_transaction_lflush(
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					struct btrfs_root *root, int num_items)
{
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	return start_transaction(root, num_items, TRANS_START,
				 BTRFS_RESERVE_FLUSH_LIMIT);
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}

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struct btrfs_trans_handle *btrfs_join_transaction(struct btrfs_root *root)
441
{
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	return start_transaction(root, 0, TRANS_JOIN, 0);
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}

445
struct btrfs_trans_handle *btrfs_join_transaction_nolock(struct btrfs_root *root)
446
{
447
	return start_transaction(root, 0, TRANS_JOIN_NOLOCK, 0);
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}

450
struct btrfs_trans_handle *btrfs_start_ioctl_transaction(struct btrfs_root *root)
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{
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	return start_transaction(root, 0, TRANS_USERSPACE, 0);
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}

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struct btrfs_trans_handle *btrfs_attach_transaction(struct btrfs_root *root)
456
{
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	return start_transaction(root, 0, TRANS_ATTACH, 0);
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}

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/* wait for a transaction commit to be fully complete */
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static noinline void wait_for_commit(struct btrfs_root *root,
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				    struct btrfs_transaction *commit)
{
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	wait_event(commit->commit_wait, commit->commit_done);
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}

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int btrfs_wait_for_commit(struct btrfs_root *root, u64 transid)
{
	struct btrfs_transaction *cur_trans = NULL, *t;
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	int ret = 0;
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	if (transid) {
		if (transid <= root->fs_info->last_trans_committed)
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			goto out;
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		ret = -EINVAL;
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		/* find specified transaction */
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		spin_lock(&root->fs_info->trans_lock);
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		list_for_each_entry(t, &root->fs_info->trans_list, list) {
			if (t->transid == transid) {
				cur_trans = t;
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				atomic_inc(&cur_trans->use_count);
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				ret = 0;
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				break;
			}
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			if (t->transid > transid) {
				ret = 0;
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				break;
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			}
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		}
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		spin_unlock(&root->fs_info->trans_lock);
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		/* The specified transaction doesn't exist */
493
		if (!cur_trans)
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			goto out;
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	} else {
		/* find newest transaction that is committing | committed */
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		spin_lock(&root->fs_info->trans_lock);
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		list_for_each_entry_reverse(t, &root->fs_info->trans_list,
					    list) {
			if (t->in_commit) {
				if (t->commit_done)
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					break;
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				cur_trans = t;
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				atomic_inc(&cur_trans->use_count);
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				break;
			}
		}
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		spin_unlock(&root->fs_info->trans_lock);
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		if (!cur_trans)
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			goto out;  /* nothing committing|committed */
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	}

	wait_for_commit(root, cur_trans);
	put_transaction(cur_trans);
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out:
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	return ret;
}

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void btrfs_throttle(struct btrfs_root *root)
{
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	if (!atomic_read(&root->fs_info->open_ioctl_trans))
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		wait_current_trans(root);
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}

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static int should_end_transaction(struct btrfs_trans_handle *trans,
				  struct btrfs_root *root)
{
	int ret;
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	ret = btrfs_block_rsv_check(root, &root->fs_info->global_block_rsv, 5);
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	return ret ? 1 : 0;
}

int btrfs_should_end_transaction(struct btrfs_trans_handle *trans,
				 struct btrfs_root *root)
{
	struct btrfs_transaction *cur_trans = trans->transaction;
	int updates;
539
	int err;
540

J
Josef Bacik 已提交
541
	smp_mb();
542 543 544 545 546
	if (cur_trans->blocked || cur_trans->delayed_refs.flushing)
		return 1;

	updates = trans->delayed_ref_updates;
	trans->delayed_ref_updates = 0;
547 548 549 550 551
	if (updates) {
		err = btrfs_run_delayed_refs(trans, root, updates);
		if (err) /* Error code will also eval true */
			return err;
	}
552 553 554 555

	return should_end_transaction(trans, root);
}

556
static int __btrfs_end_transaction(struct btrfs_trans_handle *trans,
557
			  struct btrfs_root *root, int throttle)
C
Chris Mason 已提交
558
{
559
	struct btrfs_transaction *cur_trans = trans->transaction;
560
	struct btrfs_fs_info *info = root->fs_info;
561
	int count = 0;
562
	int lock = (trans->type != TRANS_JOIN_NOLOCK);
563
	int err = 0;
564

565 566 567 568 569
	if (--trans->use_count) {
		trans->block_rsv = trans->orig_rsv;
		return 0;
	}

570 571 572 573 574
	/*
	 * do the qgroup accounting as early as possible
	 */
	err = btrfs_delayed_refs_qgroup_accounting(trans, info);

575
	btrfs_trans_release_metadata(trans, root);
576
	trans->block_rsv = NULL;
577 578 579 580 581
	/*
	 * the same root has to be passed to start_transaction and
	 * end_transaction. Subvolume quota depends on this.
	 */
	WARN_ON(trans->root != root);
582 583 584 585 586 587

	if (trans->qgroup_reserved) {
		btrfs_qgroup_free(root, trans->qgroup_reserved);
		trans->qgroup_reserved = 0;
	}

588 589 590
	if (!list_empty(&trans->new_bgs))
		btrfs_create_pending_block_groups(trans, root);

591
	while (count < 2) {
592 593 594 595 596 597 598 599 600 601
		unsigned long cur = trans->delayed_ref_updates;
		trans->delayed_ref_updates = 0;
		if (cur &&
		    trans->transaction->delayed_refs.num_heads_ready > 64) {
			trans->delayed_ref_updates = 0;
			btrfs_run_delayed_refs(trans, root, cur);
		} else {
			break;
		}
		count++;
602
	}
603 604
	btrfs_trans_release_metadata(trans, root);
	trans->block_rsv = NULL;
605

606 607 608
	if (!list_empty(&trans->new_bgs))
		btrfs_create_pending_block_groups(trans, root);

J
Josef Bacik 已提交
609 610
	if (lock && !atomic_read(&root->fs_info->open_ioctl_trans) &&
	    should_end_transaction(trans, root)) {
611
		trans->transaction->blocked = 1;
J
Josef Bacik 已提交
612 613
		smp_wmb();
	}
614

615
	if (lock && cur_trans->blocked && !cur_trans->in_commit) {
616 617 618 619 620 621 622
		if (throttle) {
			/*
			 * We may race with somebody else here so end up having
			 * to call end_transaction on ourselves again, so inc
			 * our use_count.
			 */
			trans->use_count++;
623
			return btrfs_commit_transaction(trans, root);
624
		} else {
625
			wake_up_process(info->transaction_kthread);
626
		}
627 628
	}

629
	if (trans->type < TRANS_JOIN_NOLOCK)
630
		sb_end_intwrite(root->fs_info->sb);
631

632
	WARN_ON(cur_trans != info->running_transaction);
633 634
	WARN_ON(atomic_read(&cur_trans->num_writers) < 1);
	atomic_dec(&cur_trans->num_writers);
635

636
	smp_mb();
C
Chris Mason 已提交
637 638 639
	if (waitqueue_active(&cur_trans->writer_wait))
		wake_up(&cur_trans->writer_wait);
	put_transaction(cur_trans);
J
Josef Bacik 已提交
640 641 642

	if (current->journal_info == trans)
		current->journal_info = NULL;
643

Y
Yan, Zheng 已提交
644 645 646
	if (throttle)
		btrfs_run_delayed_iputs(root);

647 648
	if (trans->aborted ||
	    root->fs_info->fs_state & BTRFS_SUPER_FLAG_ERROR) {
649
		err = -EIO;
650
	}
651
	assert_qgroups_uptodate(trans);
652

653 654
	kmem_cache_free(btrfs_trans_handle_cachep, trans);
	return err;
C
Chris Mason 已提交
655 656
}

657 658 659
int btrfs_end_transaction(struct btrfs_trans_handle *trans,
			  struct btrfs_root *root)
{
660 661
	int ret;

662
	ret = __btrfs_end_transaction(trans, root, 0);
663 664 665
	if (ret)
		return ret;
	return 0;
666 667 668 669 670
}

int btrfs_end_transaction_throttle(struct btrfs_trans_handle *trans,
				   struct btrfs_root *root)
{
671 672
	int ret;

673
	ret = __btrfs_end_transaction(trans, root, 1);
674 675 676 677 678 679 680 681
	if (ret)
		return ret;
	return 0;
}

int btrfs_end_transaction_dmeta(struct btrfs_trans_handle *trans,
				struct btrfs_root *root)
{
682
	return __btrfs_end_transaction(trans, root, 1);
683 684
}

C
Chris Mason 已提交
685 686 687
/*
 * 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
688
 * those extents are sent to disk but does not wait on them
C
Chris Mason 已提交
689
 */
690
int btrfs_write_marked_extents(struct btrfs_root *root,
691
			       struct extent_io_tree *dirty_pages, int mark)
C
Chris Mason 已提交
692
{
693
	int err = 0;
694
	int werr = 0;
J
Josef Bacik 已提交
695
	struct address_space *mapping = root->fs_info->btree_inode->i_mapping;
696
	struct extent_state *cached_state = NULL;
697
	u64 start = 0;
698
	u64 end;
699

J
Josef Bacik 已提交
700
	while (!find_first_extent_bit(dirty_pages, start, &start, &end,
701 702 703 704
				      mark, &cached_state)) {
		convert_extent_bit(dirty_pages, start, end, EXTENT_NEED_WAIT,
				   mark, &cached_state, GFP_NOFS);
		cached_state = NULL;
J
Josef Bacik 已提交
705 706 707 708 709
		err = filemap_fdatawrite_range(mapping, start, end);
		if (err)
			werr = err;
		cond_resched();
		start = end + 1;
710
	}
711 712 713 714 715 716 717 718 719 720 721 722
	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,
723
			      struct extent_io_tree *dirty_pages, int mark)
724 725 726
{
	int err = 0;
	int werr = 0;
J
Josef Bacik 已提交
727
	struct address_space *mapping = root->fs_info->btree_inode->i_mapping;
728
	struct extent_state *cached_state = NULL;
729 730
	u64 start = 0;
	u64 end;
731

J
Josef Bacik 已提交
732
	while (!find_first_extent_bit(dirty_pages, start, &start, &end,
733 734 735
				      EXTENT_NEED_WAIT, &cached_state)) {
		clear_extent_bit(dirty_pages, start, end, EXTENT_NEED_WAIT,
				 0, 0, &cached_state, GFP_NOFS);
J
Josef Bacik 已提交
736 737 738 739 740
		err = filemap_fdatawait_range(mapping, start, end);
		if (err)
			werr = err;
		cond_resched();
		start = end + 1;
741
	}
742 743 744
	if (err)
		werr = err;
	return werr;
C
Chris Mason 已提交
745 746
}

747 748 749 750 751 752
/*
 * 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,
753
				struct extent_io_tree *dirty_pages, int mark)
754 755 756 757
{
	int ret;
	int ret2;

758 759
	ret = btrfs_write_marked_extents(root, dirty_pages, mark);
	ret2 = btrfs_wait_marked_extents(root, dirty_pages, mark);
760 761 762 763 764 765

	if (ret)
		return ret;
	if (ret2)
		return ret2;
	return 0;
766 767
}

768 769 770 771 772 773 774 775 776
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,
777 778
					   &trans->transaction->dirty_pages,
					   EXTENT_DIRTY);
779 780
}

C
Chris Mason 已提交
781 782 783 784 785 786 787 788 789 790
/*
 * 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.
 */
791 792
static int update_cowonly_root(struct btrfs_trans_handle *trans,
			       struct btrfs_root *root)
C
Chris Mason 已提交
793 794
{
	int ret;
795
	u64 old_root_bytenr;
796
	u64 old_root_used;
797
	struct btrfs_root *tree_root = root->fs_info->tree_root;
C
Chris Mason 已提交
798

799
	old_root_used = btrfs_root_used(&root->root_item);
800
	btrfs_write_dirty_block_groups(trans, root);
801

C
Chris Mason 已提交
802
	while (1) {
803
		old_root_bytenr = btrfs_root_bytenr(&root->root_item);
804 805
		if (old_root_bytenr == root->node->start &&
		    old_root_used == btrfs_root_used(&root->root_item))
C
Chris Mason 已提交
806
			break;
807

808
		btrfs_set_root_node(&root->root_item, root->node);
C
Chris Mason 已提交
809
		ret = btrfs_update_root(trans, tree_root,
810 811
					&root->root_key,
					&root->root_item);
812 813
		if (ret)
			return ret;
814

815
		old_root_used = btrfs_root_used(&root->root_item);
816
		ret = btrfs_write_dirty_block_groups(trans, root);
817 818
		if (ret)
			return ret;
819
	}
820 821 822 823

	if (root != root->fs_info->extent_root)
		switch_commit_root(root);

824 825 826
	return 0;
}

C
Chris Mason 已提交
827 828
/*
 * update all the cowonly tree roots on disk
829 830 831 832
 *
 * The error handling in this function may not be obvious. Any of the
 * failures will cause the file system to go offline. We still need
 * to clean up the delayed refs.
C
Chris Mason 已提交
833
 */
834 835
static noinline int commit_cowonly_roots(struct btrfs_trans_handle *trans,
					 struct btrfs_root *root)
836 837 838
{
	struct btrfs_fs_info *fs_info = root->fs_info;
	struct list_head *next;
839
	struct extent_buffer *eb;
840
	int ret;
841

842
	ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1);
843 844
	if (ret)
		return ret;
845

846
	eb = btrfs_lock_root_node(fs_info->tree_root);
847 848
	ret = btrfs_cow_block(trans, fs_info->tree_root, eb, NULL,
			      0, &eb);
849 850
	btrfs_tree_unlock(eb);
	free_extent_buffer(eb);
851

852 853 854
	if (ret)
		return ret;

855
	ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1);
856 857
	if (ret)
		return ret;
858

859
	ret = btrfs_run_dev_stats(trans, root->fs_info);
860 861 862
	WARN_ON(ret);
	ret = btrfs_run_dev_replace(trans, root->fs_info);
	WARN_ON(ret);
863

864 865 866 867 868 869 870
	ret = btrfs_run_qgroups(trans, root->fs_info);
	BUG_ON(ret);

	/* run_qgroups might have added some more refs */
	ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1);
	BUG_ON(ret);

C
Chris Mason 已提交
871
	while (!list_empty(&fs_info->dirty_cowonly_roots)) {
872 873 874
		next = fs_info->dirty_cowonly_roots.next;
		list_del_init(next);
		root = list_entry(next, struct btrfs_root, dirty_list);
875

876 877 878
		ret = update_cowonly_root(trans, root);
		if (ret)
			return ret;
C
Chris Mason 已提交
879
	}
880 881 882 883 884

	down_write(&fs_info->extent_commit_sem);
	switch_commit_root(fs_info->extent_root);
	up_write(&fs_info->extent_commit_sem);

885 886
	btrfs_after_dev_replace_commit(fs_info);

C
Chris Mason 已提交
887 888 889
	return 0;
}

C
Chris Mason 已提交
890 891 892 893 894
/*
 * 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
 */
895
int btrfs_add_dead_root(struct btrfs_root *root)
896
{
J
Josef Bacik 已提交
897
	spin_lock(&root->fs_info->trans_lock);
898
	list_add(&root->root_list, &root->fs_info->dead_roots);
J
Josef Bacik 已提交
899
	spin_unlock(&root->fs_info->trans_lock);
900 901 902
	return 0;
}

C
Chris Mason 已提交
903
/*
904
 * update all the cowonly tree roots on disk
C
Chris Mason 已提交
905
 */
906 907
static noinline int commit_fs_roots(struct btrfs_trans_handle *trans,
				    struct btrfs_root *root)
908 909
{
	struct btrfs_root *gang[8];
910
	struct btrfs_fs_info *fs_info = root->fs_info;
911 912
	int i;
	int ret;
913 914
	int err = 0;

J
Josef Bacik 已提交
915
	spin_lock(&fs_info->fs_roots_radix_lock);
C
Chris Mason 已提交
916
	while (1) {
917 918
		ret = radix_tree_gang_lookup_tag(&fs_info->fs_roots_radix,
						 (void **)gang, 0,
919 920 921 922 923 924
						 ARRAY_SIZE(gang),
						 BTRFS_ROOT_TRANS_TAG);
		if (ret == 0)
			break;
		for (i = 0; i < ret; i++) {
			root = gang[i];
925 926 927
			radix_tree_tag_clear(&fs_info->fs_roots_radix,
					(unsigned long)root->root_key.objectid,
					BTRFS_ROOT_TRANS_TAG);
J
Josef Bacik 已提交
928
			spin_unlock(&fs_info->fs_roots_radix_lock);
Y
Yan Zheng 已提交
929

930
			btrfs_free_log(trans, root);
931
			btrfs_update_reloc_root(trans, root);
932
			btrfs_orphan_commit_root(trans, root);
933

934 935
			btrfs_save_ino_cache(root, trans);

936 937 938 939
			/* see comments in should_cow_block() */
			root->force_cow = 0;
			smp_wmb();

940
			if (root->commit_root != root->node) {
941
				mutex_lock(&root->fs_commit_mutex);
J
Josef Bacik 已提交
942
				switch_commit_root(root);
943 944 945
				btrfs_unpin_free_ino(root);
				mutex_unlock(&root->fs_commit_mutex);

946 947 948
				btrfs_set_root_node(&root->root_item,
						    root->node);
			}
949 950

			err = btrfs_update_root(trans, fs_info->tree_root,
951 952
						&root->root_key,
						&root->root_item);
J
Josef Bacik 已提交
953
			spin_lock(&fs_info->fs_roots_radix_lock);
954 955
			if (err)
				break;
956 957
		}
	}
J
Josef Bacik 已提交
958
	spin_unlock(&fs_info->fs_roots_radix_lock);
959
	return err;
960 961
}

C
Chris Mason 已提交
962 963 964 965
/*
 * defrag a given btree.  If cacheonly == 1, this won't read from the disk,
 * otherwise every leaf in the btree is read and defragged.
 */
966 967 968 969
int btrfs_defrag_root(struct btrfs_root *root, int cacheonly)
{
	struct btrfs_fs_info *info = root->fs_info;
	struct btrfs_trans_handle *trans;
970
	int ret;
971

972
	if (xchg(&root->defrag_running, 1))
973
		return 0;
974

975
	while (1) {
976 977 978 979
		trans = btrfs_start_transaction(root, 0);
		if (IS_ERR(trans))
			return PTR_ERR(trans);

980
		ret = btrfs_defrag_leaves(trans, root, cacheonly);
981

982
		btrfs_end_transaction(trans, root);
983
		btrfs_btree_balance_dirty(info->tree_root);
984 985
		cond_resched();

986
		if (btrfs_fs_closing(root->fs_info) || ret != -EAGAIN)
987 988 989
			break;
	}
	root->defrag_running = 0;
990
	return ret;
991 992
}

C
Chris Mason 已提交
993 994 995 996
/*
 * new snapshots need to be created at a very specific time in the
 * transaction commit.  This does the actual creation
 */
997
static noinline int create_pending_snapshot(struct btrfs_trans_handle *trans,
998 999 1000 1001
				   struct btrfs_fs_info *fs_info,
				   struct btrfs_pending_snapshot *pending)
{
	struct btrfs_key key;
1002
	struct btrfs_root_item *new_root_item;
1003 1004
	struct btrfs_root *tree_root = fs_info->tree_root;
	struct btrfs_root *root = pending->root;
1005
	struct btrfs_root *parent_root;
L
Liu Bo 已提交
1006
	struct btrfs_block_rsv *rsv;
1007
	struct inode *parent_inode;
1008 1009
	struct btrfs_path *path;
	struct btrfs_dir_item *dir_item;
1010
	struct dentry *parent;
1011
	struct dentry *dentry;
1012
	struct extent_buffer *tmp;
1013
	struct extent_buffer *old;
1014
	struct timespec cur_time = CURRENT_TIME;
1015
	int ret;
1016
	u64 to_reserve = 0;
1017
	u64 index = 0;
1018
	u64 objectid;
L
Li Zefan 已提交
1019
	u64 root_flags;
1020
	uuid_le new_uuid;
1021

1022 1023 1024 1025 1026 1027
	path = btrfs_alloc_path();
	if (!path) {
		ret = pending->error = -ENOMEM;
		goto path_alloc_fail;
	}

1028 1029
	new_root_item = kmalloc(sizeof(*new_root_item), GFP_NOFS);
	if (!new_root_item) {
1030
		ret = pending->error = -ENOMEM;
1031
		goto root_item_alloc_fail;
1032
	}
1033

1034
	ret = btrfs_find_free_objectid(tree_root, &objectid);
1035 1036
	if (ret) {
		pending->error = ret;
1037
		goto no_free_objectid;
1038
	}
1039

1040
	btrfs_reloc_pre_snapshot(trans, pending, &to_reserve);
1041 1042

	if (to_reserve > 0) {
M
Miao Xie 已提交
1043 1044 1045
		ret = btrfs_block_rsv_add(root, &pending->block_rsv,
					  to_reserve,
					  BTRFS_RESERVE_NO_FLUSH);
1046 1047
		if (ret) {
			pending->error = ret;
1048
			goto no_free_objectid;
1049 1050 1051
		}
	}

A
Arne Jansen 已提交
1052 1053 1054 1055
	ret = btrfs_qgroup_inherit(trans, fs_info, root->root_key.objectid,
				   objectid, pending->inherit);
	if (ret) {
		pending->error = ret;
1056
		goto no_free_objectid;
A
Arne Jansen 已提交
1057 1058
	}

1059
	key.objectid = objectid;
1060 1061
	key.offset = (u64)-1;
	key.type = BTRFS_ROOT_ITEM_KEY;
1062

1063
	rsv = trans->block_rsv;
1064
	trans->block_rsv = &pending->block_rsv;
1065

1066
	dentry = pending->dentry;
1067 1068
	parent = dget_parent(dentry);
	parent_inode = parent->d_inode;
1069
	parent_root = BTRFS_I(parent_inode)->root;
C
Chris Mason 已提交
1070
	record_root_in_trans(trans, parent_root);
1071

1072 1073 1074
	/*
	 * insert the directory item
	 */
1075
	ret = btrfs_set_inode_index(parent_inode, &index);
1076
	BUG_ON(ret); /* -ENOMEM */
1077 1078 1079 1080 1081 1082 1083

	/* check if there is a file/dir which has the same name. */
	dir_item = btrfs_lookup_dir_item(NULL, parent_root, path,
					 btrfs_ino(parent_inode),
					 dentry->d_name.name,
					 dentry->d_name.len, 0);
	if (dir_item != NULL && !IS_ERR(dir_item)) {
1084 1085
		pending->error = -EEXIST;
		goto fail;
1086 1087
	} else if (IS_ERR(dir_item)) {
		ret = PTR_ERR(dir_item);
1088 1089
		btrfs_abort_transaction(trans, root, ret);
		goto fail;
1090
	}
1091
	btrfs_release_path(path);
1092

1093 1094 1095 1096 1097 1098 1099
	/*
	 * pull in the delayed directory update
	 * and the delayed inode item
	 * otherwise we corrupt the FS during
	 * snapshot
	 */
	ret = btrfs_run_delayed_items(trans, root);
1100 1101 1102 1103
	if (ret) {	/* Transaction aborted */
		btrfs_abort_transaction(trans, root, ret);
		goto fail;
	}
1104

C
Chris Mason 已提交
1105
	record_root_in_trans(trans, root);
1106 1107
	btrfs_set_root_last_snapshot(&root->root_item, trans->transid);
	memcpy(new_root_item, &root->root_item, sizeof(*new_root_item));
1108
	btrfs_check_and_init_root_item(new_root_item);
1109

L
Li Zefan 已提交
1110 1111 1112 1113 1114 1115 1116
	root_flags = btrfs_root_flags(new_root_item);
	if (pending->readonly)
		root_flags |= BTRFS_ROOT_SUBVOL_RDONLY;
	else
		root_flags &= ~BTRFS_ROOT_SUBVOL_RDONLY;
	btrfs_set_root_flags(new_root_item, root_flags);

1117 1118 1119 1120 1121 1122 1123
	btrfs_set_root_generation_v2(new_root_item,
			trans->transid);
	uuid_le_gen(&new_uuid);
	memcpy(new_root_item->uuid, new_uuid.b, BTRFS_UUID_SIZE);
	memcpy(new_root_item->parent_uuid, root->root_item.uuid,
			BTRFS_UUID_SIZE);
	new_root_item->otime.sec = cpu_to_le64(cur_time.tv_sec);
1124
	new_root_item->otime.nsec = cpu_to_le32(cur_time.tv_nsec);
1125 1126 1127 1128 1129 1130
	btrfs_set_root_otransid(new_root_item, trans->transid);
	memset(&new_root_item->stime, 0, sizeof(new_root_item->stime));
	memset(&new_root_item->rtime, 0, sizeof(new_root_item->rtime));
	btrfs_set_root_stransid(new_root_item, 0);
	btrfs_set_root_rtransid(new_root_item, 0);

1131
	old = btrfs_lock_root_node(root);
1132
	ret = btrfs_cow_block(trans, root, old, NULL, 0, &old);
1133 1134 1135
	if (ret) {
		btrfs_tree_unlock(old);
		free_extent_buffer(old);
1136 1137
		btrfs_abort_transaction(trans, root, ret);
		goto fail;
1138
	}
1139

1140 1141
	btrfs_set_lock_blocking(old);

1142
	ret = btrfs_copy_root(trans, root, old, &tmp, objectid);
1143
	/* clean up in any case */
1144 1145
	btrfs_tree_unlock(old);
	free_extent_buffer(old);
1146 1147 1148 1149
	if (ret) {
		btrfs_abort_transaction(trans, root, ret);
		goto fail;
	}
1150

1151 1152 1153 1154
	/* see comments in should_cow_block() */
	root->force_cow = 1;
	smp_wmb();

1155
	btrfs_set_root_node(new_root_item, tmp);
1156 1157 1158
	/* record when the snapshot was created in key.offset */
	key.offset = trans->transid;
	ret = btrfs_insert_root(trans, tree_root, &key, new_root_item);
1159 1160
	btrfs_tree_unlock(tmp);
	free_extent_buffer(tmp);
1161 1162 1163 1164
	if (ret) {
		btrfs_abort_transaction(trans, root, ret);
		goto fail;
	}
1165

1166 1167 1168 1169
	/*
	 * insert root back/forward references
	 */
	ret = btrfs_add_root_ref(trans, tree_root, objectid,
1170
				 parent_root->root_key.objectid,
L
Li Zefan 已提交
1171
				 btrfs_ino(parent_inode), index,
1172
				 dentry->d_name.name, dentry->d_name.len);
1173 1174 1175 1176
	if (ret) {
		btrfs_abort_transaction(trans, root, ret);
		goto fail;
	}
1177

1178 1179
	key.offset = (u64)-1;
	pending->snap = btrfs_read_fs_root_no_name(root->fs_info, &key);
1180 1181
	if (IS_ERR(pending->snap)) {
		ret = PTR_ERR(pending->snap);
1182 1183
		btrfs_abort_transaction(trans, root, ret);
		goto fail;
1184
	}
1185

1186
	ret = btrfs_reloc_post_snapshot(trans, pending);
1187 1188 1189 1190
	if (ret) {
		btrfs_abort_transaction(trans, root, ret);
		goto fail;
	}
1191 1192

	ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1);
1193 1194 1195 1196
	if (ret) {
		btrfs_abort_transaction(trans, root, ret);
		goto fail;
	}
1197 1198 1199 1200 1201 1202

	ret = btrfs_insert_dir_item(trans, parent_root,
				    dentry->d_name.name, dentry->d_name.len,
				    parent_inode, &key,
				    BTRFS_FT_DIR, index);
	/* We have check then name at the beginning, so it is impossible. */
C
Chris Mason 已提交
1203
	BUG_ON(ret == -EEXIST || ret == -EOVERFLOW);
1204 1205 1206 1207
	if (ret) {
		btrfs_abort_transaction(trans, root, ret);
		goto fail;
	}
1208 1209 1210 1211

	btrfs_i_size_write(parent_inode, parent_inode->i_size +
					 dentry->d_name.len * 2);
	parent_inode->i_mtime = parent_inode->i_ctime = CURRENT_TIME;
1212
	ret = btrfs_update_inode_fallback(trans, parent_root, parent_inode);
1213
	if (ret)
1214
		btrfs_abort_transaction(trans, root, ret);
1215
fail:
1216
	dput(parent);
L
Liu Bo 已提交
1217
	trans->block_rsv = rsv;
1218 1219 1220
no_free_objectid:
	kfree(new_root_item);
root_item_alloc_fail:
1221 1222
	btrfs_free_path(path);
path_alloc_fail:
1223
	btrfs_block_rsv_release(root, &pending->block_rsv, (u64)-1);
1224
	return ret;
1225 1226
}

C
Chris Mason 已提交
1227 1228 1229
/*
 * create all the snapshots we've scheduled for creation
 */
1230 1231
static noinline int create_pending_snapshots(struct btrfs_trans_handle *trans,
					     struct btrfs_fs_info *fs_info)
1232 1233 1234 1235
{
	struct btrfs_pending_snapshot *pending;
	struct list_head *head = &trans->transaction->pending_snapshots;

1236 1237
	list_for_each_entry(pending, head, list)
		create_pending_snapshot(trans, fs_info, pending);
1238 1239 1240
	return 0;
}

1241 1242 1243 1244 1245
static void update_super_roots(struct btrfs_root *root)
{
	struct btrfs_root_item *root_item;
	struct btrfs_super_block *super;

1246
	super = root->fs_info->super_copy;
1247 1248 1249 1250 1251 1252 1253 1254 1255 1256

	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;
1257
	if (btrfs_test_opt(root, SPACE_CACHE))
1258
		super->cache_generation = root_item->generation;
1259 1260
}

1261 1262 1263
int btrfs_transaction_in_commit(struct btrfs_fs_info *info)
{
	int ret = 0;
J
Josef Bacik 已提交
1264
	spin_lock(&info->trans_lock);
1265 1266
	if (info->running_transaction)
		ret = info->running_transaction->in_commit;
J
Josef Bacik 已提交
1267
	spin_unlock(&info->trans_lock);
1268 1269 1270
	return ret;
}

1271 1272 1273
int btrfs_transaction_blocked(struct btrfs_fs_info *info)
{
	int ret = 0;
J
Josef Bacik 已提交
1274
	spin_lock(&info->trans_lock);
1275 1276
	if (info->running_transaction)
		ret = info->running_transaction->blocked;
J
Josef Bacik 已提交
1277
	spin_unlock(&info->trans_lock);
1278 1279 1280
	return ret;
}

S
Sage Weil 已提交
1281 1282 1283 1284 1285 1286 1287
/*
 * wait for the current transaction commit to start and block subsequent
 * transaction joins
 */
static void wait_current_trans_commit_start(struct btrfs_root *root,
					    struct btrfs_transaction *trans)
{
L
Li Zefan 已提交
1288
	wait_event(root->fs_info->transaction_blocked_wait, trans->in_commit);
S
Sage Weil 已提交
1289 1290 1291 1292 1293 1294 1295 1296 1297
}

/*
 * wait for the current transaction to start and then become unblocked.
 * caller holds ref.
 */
static void wait_current_trans_commit_start_and_unblock(struct btrfs_root *root,
					 struct btrfs_transaction *trans)
{
L
Li Zefan 已提交
1298 1299
	wait_event(root->fs_info->transaction_wait,
		   trans->commit_done || (trans->in_commit && !trans->blocked));
S
Sage Weil 已提交
1300 1301 1302 1303 1304 1305 1306 1307 1308
}

/*
 * commit transactions asynchronously. once btrfs_commit_transaction_async
 * returns, any subsequent transaction will not be allowed to join.
 */
struct btrfs_async_commit {
	struct btrfs_trans_handle *newtrans;
	struct btrfs_root *root;
1309
	struct work_struct work;
S
Sage Weil 已提交
1310 1311 1312 1313 1314
};

static void do_async_commit(struct work_struct *work)
{
	struct btrfs_async_commit *ac =
1315
		container_of(work, struct btrfs_async_commit, work);
S
Sage Weil 已提交
1316

1317 1318 1319 1320
	/*
	 * We've got freeze protection passed with the transaction.
	 * Tell lockdep about it.
	 */
1321 1322 1323 1324
	if (ac->newtrans->type < TRANS_JOIN_NOLOCK)
		rwsem_acquire_read(
		     &ac->root->fs_info->sb->s_writers.lock_map[SB_FREEZE_FS-1],
		     0, 1, _THIS_IP_);
1325

1326 1327
	current->journal_info = ac->newtrans;

S
Sage Weil 已提交
1328 1329 1330 1331 1332 1333 1334 1335 1336 1337 1338 1339
	btrfs_commit_transaction(ac->newtrans, ac->root);
	kfree(ac);
}

int btrfs_commit_transaction_async(struct btrfs_trans_handle *trans,
				   struct btrfs_root *root,
				   int wait_for_unblock)
{
	struct btrfs_async_commit *ac;
	struct btrfs_transaction *cur_trans;

	ac = kmalloc(sizeof(*ac), GFP_NOFS);
T
Tsutomu Itoh 已提交
1340 1341
	if (!ac)
		return -ENOMEM;
S
Sage Weil 已提交
1342

1343
	INIT_WORK(&ac->work, do_async_commit);
S
Sage Weil 已提交
1344
	ac->root = root;
1345
	ac->newtrans = btrfs_join_transaction(root);
1346 1347 1348 1349 1350
	if (IS_ERR(ac->newtrans)) {
		int err = PTR_ERR(ac->newtrans);
		kfree(ac);
		return err;
	}
S
Sage Weil 已提交
1351 1352 1353

	/* take transaction reference */
	cur_trans = trans->transaction;
1354
	atomic_inc(&cur_trans->use_count);
S
Sage Weil 已提交
1355 1356

	btrfs_end_transaction(trans, root);
1357 1358 1359 1360 1361

	/*
	 * Tell lockdep we've released the freeze rwsem, since the
	 * async commit thread will be the one to unlock it.
	 */
1362 1363 1364 1365
	if (trans->type < TRANS_JOIN_NOLOCK)
		rwsem_release(
			&root->fs_info->sb->s_writers.lock_map[SB_FREEZE_FS-1],
			1, _THIS_IP_);
1366

1367
	schedule_work(&ac->work);
S
Sage Weil 已提交
1368 1369 1370 1371 1372 1373 1374

	/* wait for transaction to start and unblock */
	if (wait_for_unblock)
		wait_current_trans_commit_start_and_unblock(root, cur_trans);
	else
		wait_current_trans_commit_start(root, cur_trans);

1375 1376 1377 1378
	if (current->journal_info == trans)
		current->journal_info = NULL;

	put_transaction(cur_trans);
S
Sage Weil 已提交
1379 1380 1381
	return 0;
}

1382 1383

static void cleanup_transaction(struct btrfs_trans_handle *trans,
1384
				struct btrfs_root *root, int err)
1385 1386 1387 1388 1389
{
	struct btrfs_transaction *cur_trans = trans->transaction;

	WARN_ON(trans->use_count > 1);

1390 1391
	btrfs_abort_transaction(trans, root, err);

1392 1393
	spin_lock(&root->fs_info->trans_lock);
	list_del_init(&cur_trans->list);
1394 1395 1396 1397
	if (cur_trans == root->fs_info->running_transaction) {
		root->fs_info->running_transaction = NULL;
		root->fs_info->trans_no_join = 0;
	}
1398 1399 1400 1401 1402 1403 1404 1405 1406 1407 1408 1409 1410 1411 1412 1413 1414
	spin_unlock(&root->fs_info->trans_lock);

	btrfs_cleanup_one_transaction(trans->transaction, root);

	put_transaction(cur_trans);
	put_transaction(cur_trans);

	trace_btrfs_transaction_commit(root);

	btrfs_scrub_continue(root);

	if (current->journal_info == trans)
		current->journal_info = NULL;

	kmem_cache_free(btrfs_trans_handle_cachep, trans);
}

1415 1416 1417 1418 1419 1420 1421 1422 1423 1424 1425 1426 1427 1428 1429
static int btrfs_flush_all_pending_stuffs(struct btrfs_trans_handle *trans,
					  struct btrfs_root *root)
{
	int flush_on_commit = btrfs_test_opt(root, FLUSHONCOMMIT);
	int snap_pending = 0;
	int ret;

	if (!flush_on_commit) {
		spin_lock(&root->fs_info->trans_lock);
		if (!list_empty(&trans->transaction->pending_snapshots))
			snap_pending = 1;
		spin_unlock(&root->fs_info->trans_lock);
	}

	if (flush_on_commit || snap_pending) {
1430 1431 1432
		ret = btrfs_start_delalloc_inodes(root, 1);
		if (ret)
			return ret;
1433 1434 1435 1436 1437 1438 1439 1440 1441 1442 1443 1444 1445 1446 1447 1448 1449 1450 1451 1452 1453
		btrfs_wait_ordered_extents(root, 1);
	}

	ret = btrfs_run_delayed_items(trans, root);
	if (ret)
		return ret;

	/*
	 * running the delayed items may have added new refs. account
	 * them now so that they hinder processing of more delayed refs
	 * as little as possible.
	 */
	btrfs_delayed_refs_qgroup_accounting(trans, root->fs_info);

	/*
	 * 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
	 */
1454
	ret = btrfs_run_ordered_operations(root, 1);
1455

1456
	return ret;
1457 1458
}

S
Sage Weil 已提交
1459 1460 1461 1462 1463 1464 1465
/*
 * btrfs_transaction state sequence:
 *    in_commit = 0, blocked = 0  (initial)
 *    in_commit = 1, blocked = 1
 *    blocked = 0
 *    commit_done = 1
 */
C
Chris Mason 已提交
1466 1467 1468
int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
			     struct btrfs_root *root)
{
1469
	unsigned long joined = 0;
1470
	struct btrfs_transaction *cur_trans = trans->transaction;
C
Chris Mason 已提交
1471
	struct btrfs_transaction *prev_trans = NULL;
C
Chris Mason 已提交
1472
	DEFINE_WAIT(wait);
1473
	int ret;
1474 1475
	int should_grow = 0;
	unsigned long now = get_seconds();
C
Chris Mason 已提交
1476

1477 1478 1479 1480 1481
	ret = btrfs_run_ordered_operations(root, 0);
	if (ret) {
		btrfs_abort_transaction(trans, root, ret);
		goto cleanup_transaction;
	}
1482

1483 1484
	/* Stop the commit early if ->aborted is set */
	if (unlikely(ACCESS_ONCE(cur_trans->aborted))) {
1485
		ret = cur_trans->aborted;
1486
		goto cleanup_transaction;
1487
	}
1488

1489 1490 1491 1492
	/* 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);
1493 1494
	if (ret)
		goto cleanup_transaction;
1495

1496 1497 1498
	btrfs_trans_release_metadata(trans, root);
	trans->block_rsv = NULL;

1499
	cur_trans = trans->transaction;
1500

1501 1502 1503 1504
	/*
	 * set the flushing flag so procs in this transaction have to
	 * start sending their work down.
	 */
1505
	cur_trans->delayed_refs.flushing = 1;
1506

1507 1508 1509
	if (!list_empty(&trans->new_bgs))
		btrfs_create_pending_block_groups(trans, root);

1510
	ret = btrfs_run_delayed_refs(trans, root, 0);
1511 1512
	if (ret)
		goto cleanup_transaction;
1513

J
Josef Bacik 已提交
1514
	spin_lock(&cur_trans->commit_lock);
1515
	if (cur_trans->in_commit) {
J
Josef Bacik 已提交
1516
		spin_unlock(&cur_trans->commit_lock);
1517
		atomic_inc(&cur_trans->use_count);
1518
		ret = btrfs_end_transaction(trans, root);
C
Chris Mason 已提交
1519

1520
		wait_for_commit(root, cur_trans);
1521

C
Chris Mason 已提交
1522
		put_transaction(cur_trans);
1523

1524
		return ret;
C
Chris Mason 已提交
1525
	}
1526

C
Chris Mason 已提交
1527
	trans->transaction->in_commit = 1;
1528
	trans->transaction->blocked = 1;
J
Josef Bacik 已提交
1529
	spin_unlock(&cur_trans->commit_lock);
S
Sage Weil 已提交
1530 1531
	wake_up(&root->fs_info->transaction_blocked_wait);

J
Josef Bacik 已提交
1532
	spin_lock(&root->fs_info->trans_lock);
C
Chris Mason 已提交
1533 1534 1535 1536
	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) {
1537
			atomic_inc(&prev_trans->use_count);
J
Josef Bacik 已提交
1538
			spin_unlock(&root->fs_info->trans_lock);
C
Chris Mason 已提交
1539 1540 1541

			wait_for_commit(root, prev_trans);

1542
			put_transaction(prev_trans);
J
Josef Bacik 已提交
1543 1544
		} else {
			spin_unlock(&root->fs_info->trans_lock);
C
Chris Mason 已提交
1545
		}
J
Josef Bacik 已提交
1546 1547
	} else {
		spin_unlock(&root->fs_info->trans_lock);
C
Chris Mason 已提交
1548
	}
1549

1550 1551
	if (!btrfs_test_opt(root, SSD) &&
	    (now < cur_trans->start_time || now - cur_trans->start_time < 1))
1552 1553
		should_grow = 1;

1554 1555
	do {
		joined = cur_trans->num_joined;
1556

C
Chris Mason 已提交
1557
		WARN_ON(cur_trans != trans->transaction);
1558

1559
		ret = btrfs_flush_all_pending_stuffs(trans, root);
1560 1561
		if (ret)
			goto cleanup_transaction;
1562

1563 1564 1565
		prepare_to_wait(&cur_trans->writer_wait, &wait,
				TASK_UNINTERRUPTIBLE);

1566
		if (atomic_read(&cur_trans->num_writers) > 1)
1567 1568 1569
			schedule_timeout(MAX_SCHEDULE_TIMEOUT);
		else if (should_grow)
			schedule_timeout(1);
1570 1571

		finish_wait(&cur_trans->writer_wait, &wait);
1572
	} while (atomic_read(&cur_trans->num_writers) > 1 ||
1573
		 (should_grow && cur_trans->num_joined != joined));
1574

1575 1576 1577 1578
	ret = btrfs_flush_all_pending_stuffs(trans, root);
	if (ret)
		goto cleanup_transaction;

1579 1580 1581 1582 1583 1584 1585 1586 1587 1588 1589
	/*
	 * Ok now we need to make sure to block out any other joins while we
	 * commit the transaction.  We could have started a join before setting
	 * no_join so make sure to wait for num_writers to == 1 again.
	 */
	spin_lock(&root->fs_info->trans_lock);
	root->fs_info->trans_no_join = 1;
	spin_unlock(&root->fs_info->trans_lock);
	wait_event(cur_trans->writer_wait,
		   atomic_read(&cur_trans->num_writers) == 1);

1590 1591 1592 1593 1594
	/* ->aborted might be set after the previous check, so check it */
	if (unlikely(ACCESS_ONCE(cur_trans->aborted))) {
		ret = cur_trans->aborted;
		goto cleanup_transaction;
	}
C
Chris Mason 已提交
1595 1596 1597 1598 1599 1600 1601
	/*
	 * the reloc mutex makes sure that we stop
	 * the balancing code from coming in and moving
	 * extents around in the middle of the commit
	 */
	mutex_lock(&root->fs_info->reloc_mutex);

1602 1603 1604 1605 1606 1607
	/*
	 * We needn't worry about the delayed items because we will
	 * deal with them in create_pending_snapshot(), which is the
	 * core function of the snapshot creation.
	 */
	ret = create_pending_snapshots(trans, root->fs_info);
1608 1609 1610 1611
	if (ret) {
		mutex_unlock(&root->fs_info->reloc_mutex);
		goto cleanup_transaction;
	}
1612

1613 1614 1615 1616 1617 1618 1619 1620 1621 1622 1623
	/*
	 * We insert the dir indexes of the snapshots and update the inode
	 * of the snapshots' parents after the snapshot creation, so there
	 * are some delayed items which are not dealt with. Now deal with
	 * them.
	 *
	 * We needn't worry that this operation will corrupt the snapshots,
	 * because all the tree which are snapshoted will be forced to COW
	 * the nodes and leaves.
	 */
	ret = btrfs_run_delayed_items(trans, root);
1624 1625 1626 1627
	if (ret) {
		mutex_unlock(&root->fs_info->reloc_mutex);
		goto cleanup_transaction;
	}
1628

1629
	ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1);
1630 1631 1632 1633
	if (ret) {
		mutex_unlock(&root->fs_info->reloc_mutex);
		goto cleanup_transaction;
	}
1634

1635 1636 1637 1638 1639 1640
	/*
	 * make sure none of the code above managed to slip in a
	 * delayed item
	 */
	btrfs_assert_delayed_root_empty(root);

C
Chris Mason 已提交
1641
	WARN_ON(cur_trans != trans->transaction);
C
Chris Mason 已提交
1642

A
Arne Jansen 已提交
1643
	btrfs_scrub_pause(root);
1644 1645 1646 1647 1648 1649 1650 1651 1652 1653 1654 1655 1656 1657 1658
	/* 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);

1659
	ret = commit_fs_roots(trans, root);
1660 1661
	if (ret) {
		mutex_unlock(&root->fs_info->tree_log_mutex);
1662
		mutex_unlock(&root->fs_info->reloc_mutex);
1663 1664
		goto cleanup_transaction;
	}
1665

1666
	/* commit_fs_roots gets rid of all the tree log roots, it is now
1667 1668 1669 1670
	 * safe to free the root of tree log roots
	 */
	btrfs_free_log_root_tree(trans, root->fs_info);

1671
	ret = commit_cowonly_roots(trans, root);
1672 1673
	if (ret) {
		mutex_unlock(&root->fs_info->tree_log_mutex);
1674
		mutex_unlock(&root->fs_info->reloc_mutex);
1675 1676
		goto cleanup_transaction;
	}
1677

1678 1679 1680 1681 1682 1683 1684 1685 1686 1687 1688
	/*
	 * The tasks which save the space cache and inode cache may also
	 * update ->aborted, check it.
	 */
	if (unlikely(ACCESS_ONCE(cur_trans->aborted))) {
		ret = cur_trans->aborted;
		mutex_unlock(&root->fs_info->tree_log_mutex);
		mutex_unlock(&root->fs_info->reloc_mutex);
		goto cleanup_transaction;
	}

1689 1690
	btrfs_prepare_extent_commit(trans, root);

C
Chris Mason 已提交
1691
	cur_trans = root->fs_info->running_transaction;
1692 1693 1694

	btrfs_set_root_node(&root->fs_info->tree_root->root_item,
			    root->fs_info->tree_root->node);
J
Josef Bacik 已提交
1695
	switch_commit_root(root->fs_info->tree_root);
1696 1697 1698

	btrfs_set_root_node(&root->fs_info->chunk_root->root_item,
			    root->fs_info->chunk_root->node);
J
Josef Bacik 已提交
1699
	switch_commit_root(root->fs_info->chunk_root);
1700

1701
	assert_qgroups_uptodate(trans);
1702
	update_super_roots(root);
1703 1704

	if (!root->fs_info->log_root_recovering) {
1705 1706
		btrfs_set_super_log_root(root->fs_info->super_copy, 0);
		btrfs_set_super_log_root_level(root->fs_info->super_copy, 0);
1707 1708
	}

1709 1710
	memcpy(root->fs_info->super_for_commit, root->fs_info->super_copy,
	       sizeof(*root->fs_info->super_copy));
C
Chris Mason 已提交
1711

1712
	trans->transaction->blocked = 0;
J
Josef Bacik 已提交
1713 1714 1715 1716
	spin_lock(&root->fs_info->trans_lock);
	root->fs_info->running_transaction = NULL;
	root->fs_info->trans_no_join = 0;
	spin_unlock(&root->fs_info->trans_lock);
C
Chris Mason 已提交
1717
	mutex_unlock(&root->fs_info->reloc_mutex);
1718

1719
	wake_up(&root->fs_info->transaction_wait);
1720

C
Chris Mason 已提交
1721
	ret = btrfs_write_and_wait_transaction(trans, root);
1722 1723 1724 1725 1726 1727 1728 1729 1730 1731 1732 1733
	if (ret) {
		btrfs_error(root->fs_info, ret,
			    "Error while writing out transaction.");
		mutex_unlock(&root->fs_info->tree_log_mutex);
		goto cleanup_transaction;
	}

	ret = write_ctree_super(trans, root, 0);
	if (ret) {
		mutex_unlock(&root->fs_info->tree_log_mutex);
		goto cleanup_transaction;
	}
1734

1735 1736 1737 1738 1739 1740
	/*
	 * the super is written, we can safely allow the tree-loggers
	 * to go about their business
	 */
	mutex_unlock(&root->fs_info->tree_log_mutex);

1741
	btrfs_finish_extent_commit(trans, root);
1742

C
Chris Mason 已提交
1743
	cur_trans->commit_done = 1;
1744

1745
	root->fs_info->last_trans_committed = cur_trans->transid;
J
Josef Bacik 已提交
1746

C
Chris Mason 已提交
1747
	wake_up(&cur_trans->commit_wait);
1748

J
Josef Bacik 已提交
1749
	spin_lock(&root->fs_info->trans_lock);
1750
	list_del_init(&cur_trans->list);
J
Josef Bacik 已提交
1751 1752
	spin_unlock(&root->fs_info->trans_lock);

C
Chris Mason 已提交
1753
	put_transaction(cur_trans);
C
Chris Mason 已提交
1754
	put_transaction(cur_trans);
1755

1756 1757
	if (trans->type < TRANS_JOIN_NOLOCK)
		sb_end_intwrite(root->fs_info->sb);
1758

1759 1760
	trace_btrfs_transaction_commit(root);

A
Arne Jansen 已提交
1761 1762
	btrfs_scrub_continue(root);

J
Josef Bacik 已提交
1763 1764 1765
	if (current->journal_info == trans)
		current->journal_info = NULL;

C
Chris Mason 已提交
1766
	kmem_cache_free(btrfs_trans_handle_cachep, trans);
Y
Yan, Zheng 已提交
1767 1768 1769 1770

	if (current != root->fs_info->transaction_kthread)
		btrfs_run_delayed_iputs(root);

C
Chris Mason 已提交
1771
	return ret;
1772 1773

cleanup_transaction:
1774 1775
	btrfs_trans_release_metadata(trans, root);
	trans->block_rsv = NULL;
1776 1777 1778 1779
	btrfs_printk(root->fs_info, "Skipping commit of aborted transaction.\n");
//	WARN_ON(1);
	if (current->journal_info == trans)
		current->journal_info = NULL;
1780
	cleanup_transaction(trans, root, ret);
1781 1782

	return ret;
C
Chris Mason 已提交
1783 1784
}

C
Chris Mason 已提交
1785 1786 1787
/*
 * interface function to delete all the snapshots we have scheduled for deletion
 */
1788 1789
int btrfs_clean_old_snapshots(struct btrfs_root *root)
{
1790 1791 1792
	LIST_HEAD(list);
	struct btrfs_fs_info *fs_info = root->fs_info;

J
Josef Bacik 已提交
1793
	spin_lock(&fs_info->trans_lock);
1794
	list_splice_init(&fs_info->dead_roots, &list);
J
Josef Bacik 已提交
1795
	spin_unlock(&fs_info->trans_lock);
1796

1797
	while (!list_empty(&list)) {
1798 1799
		int ret;

1800
		root = list_entry(list.next, struct btrfs_root, root_list);
1801 1802
		list_del(&root->root_list);

1803 1804
		btrfs_kill_all_delayed_nodes(root);

1805 1806
		if (btrfs_header_backref_rev(root->node) <
		    BTRFS_MIXED_BACKREF_REV)
1807
			ret = btrfs_drop_snapshot(root, NULL, 0, 0);
1808
		else
1809 1810
			ret =btrfs_drop_snapshot(root, NULL, 1, 0);
		BUG_ON(ret < 0);
1811 1812 1813
	}
	return 0;
}