transaction.c 43.0 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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#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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		memset(transaction, 0, sizeof(*transaction));
		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 nofail)
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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 (!nofail) {
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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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	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();
	if (!list_empty(&fs_info->tree_mod_seq_list)) {
		printk(KERN_ERR "btrfs: tree_mod_seq_list not empty when "
			"creating a fresh transaction\n");
		WARN_ON(1);
	}
	if (!RB_EMPTY_ROOT(&fs_info->tree_mod_log)) {
		printk(KERN_ERR "btrfs: tree_mod_log rb tree not empty when "
			"creating a fresh transaction\n");
		WARN_ON(1);
	}
	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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enum btrfs_trans_type {
	TRANS_START,
	TRANS_JOIN,
	TRANS_USERSPACE,
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	TRANS_JOIN_NOLOCK,
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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,
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						    u64 num_items, int type)
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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++;
		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,
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					  &root->fs_info->trans_block_rsv,
					  num_bytes);
		if (ret)
			return ERR_PTR(ret);
	}
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again:
	h = kmem_cache_alloc(btrfs_trans_handle_cachep, GFP_NOFS);
	if (!h)
		return ERR_PTR(-ENOMEM);
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	sb_start_intwrite(root->fs_info->sb);

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	if (may_wait_transaction(root, type))
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		wait_current_trans(root);
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	do {
		ret = join_transaction(root, type == TRANS_JOIN_NOLOCK);
		if (ret == -EBUSY)
			wait_current_trans(root);
	} while (ret == -EBUSY);

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	if (ret < 0) {
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		sb_end_intwrite(root->fs_info->sb);
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		kmem_cache_free(btrfs_trans_handle_cachep, h);
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		return ERR_PTR(ret);
	}
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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;
	INIT_LIST_HEAD(&h->qgroup_ref_list);
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	smp_mb();
	if (cur_trans->blocked && may_wait_transaction(root, type)) {
		btrfs_commit_transaction(h, root);
		goto again;
	}

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	if (num_bytes) {
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		trace_btrfs_space_reservation(root->fs_info, "transaction",
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					      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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struct btrfs_trans_handle *btrfs_start_transaction(struct btrfs_root *root,
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						   int num_items)
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{
396
	return start_transaction(root, num_items, TRANS_START);
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}
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struct btrfs_trans_handle *btrfs_join_transaction(struct btrfs_root *root)
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{
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	return start_transaction(root, 0, TRANS_JOIN);
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}

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

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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);
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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;
	int ret;

	ret = 0;
	if (transid) {
		if (transid <= root->fs_info->last_trans_committed)
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			goto out;
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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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				break;
			}
			if (t->transid > transid)
				break;
		}
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		spin_unlock(&root->fs_info->trans_lock);
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		ret = -EINVAL;
		if (!cur_trans)
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			goto out;  /* bad transid */
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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);
	ret = 0;
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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;
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	int err;
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	smp_mb();
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	if (cur_trans->blocked || cur_trans->delayed_refs.flushing)
		return 1;

	updates = trans->delayed_ref_updates;
	trans->delayed_ref_updates = 0;
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	if (updates) {
		err = btrfs_run_delayed_refs(trans, root, updates);
		if (err) /* Error code will also eval true */
			return err;
	}
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	return should_end_transaction(trans, root);
}

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static int __btrfs_end_transaction(struct btrfs_trans_handle *trans,
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			  struct btrfs_root *root, int throttle, int lock)
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{
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	struct btrfs_transaction *cur_trans = trans->transaction;
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	struct btrfs_fs_info *info = root->fs_info;
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	int count = 0;
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	int err = 0;
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	if (--trans->use_count) {
		trans->block_rsv = trans->orig_rsv;
		return 0;
	}

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	/*
	 * do the qgroup accounting as early as possible
	 */
	err = btrfs_delayed_refs_qgroup_accounting(trans, info);

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	btrfs_trans_release_metadata(trans, root);
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	trans->block_rsv = NULL;
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	/*
	 * the same root has to be passed to start_transaction and
	 * end_transaction. Subvolume quota depends on this.
	 */
	WARN_ON(trans->root != root);
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	if (trans->qgroup_reserved) {
		btrfs_qgroup_free(root, trans->qgroup_reserved);
		trans->qgroup_reserved = 0;
	}

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	while (count < 2) {
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		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++;
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	}
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	btrfs_trans_release_metadata(trans, root);
	trans->block_rsv = NULL;
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	sb_end_intwrite(root->fs_info->sb);

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	if (lock && !atomic_read(&root->fs_info->open_ioctl_trans) &&
	    should_end_transaction(trans, root)) {
558
		trans->transaction->blocked = 1;
J
Josef Bacik 已提交
559 560
		smp_wmb();
	}
561

562
	if (lock && cur_trans->blocked && !cur_trans->in_commit) {
563 564 565 566 567 568 569
		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++;
570
			return btrfs_commit_transaction(trans, root);
571
		} else {
572
			wake_up_process(info->transaction_kthread);
573
		}
574 575 576
	}

	WARN_ON(cur_trans != info->running_transaction);
577 578
	WARN_ON(atomic_read(&cur_trans->num_writers) < 1);
	atomic_dec(&cur_trans->num_writers);
579

580
	smp_mb();
C
Chris Mason 已提交
581 582 583
	if (waitqueue_active(&cur_trans->writer_wait))
		wake_up(&cur_trans->writer_wait);
	put_transaction(cur_trans);
J
Josef Bacik 已提交
584 585 586

	if (current->journal_info == trans)
		current->journal_info = NULL;
587

Y
Yan, Zheng 已提交
588 589 590
	if (throttle)
		btrfs_run_delayed_iputs(root);

591 592
	if (trans->aborted ||
	    root->fs_info->fs_state & BTRFS_SUPER_FLAG_ERROR) {
593
		err = -EIO;
594
	}
595
	assert_qgroups_uptodate(trans);
596

597 598 599
	memset(trans, 0, sizeof(*trans));
	kmem_cache_free(btrfs_trans_handle_cachep, trans);
	return err;
C
Chris Mason 已提交
600 601
}

602 603 604
int btrfs_end_transaction(struct btrfs_trans_handle *trans,
			  struct btrfs_root *root)
{
605 606 607 608 609 610
	int ret;

	ret = __btrfs_end_transaction(trans, root, 0, 1);
	if (ret)
		return ret;
	return 0;
611 612 613 614 615
}

int btrfs_end_transaction_throttle(struct btrfs_trans_handle *trans,
				   struct btrfs_root *root)
{
616 617 618 619 620 621
	int ret;

	ret = __btrfs_end_transaction(trans, root, 1, 1);
	if (ret)
		return ret;
	return 0;
622 623 624 625 626
}

int btrfs_end_transaction_nolock(struct btrfs_trans_handle *trans,
				 struct btrfs_root *root)
{
627 628 629 630 631 632 633 634 635 636 637 638
	int ret;

	ret = __btrfs_end_transaction(trans, root, 0, 0);
	if (ret)
		return ret;
	return 0;
}

int btrfs_end_transaction_dmeta(struct btrfs_trans_handle *trans,
				struct btrfs_root *root)
{
	return __btrfs_end_transaction(trans, root, 1, 1);
639 640
}

C
Chris Mason 已提交
641 642 643
/*
 * 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
644
 * those extents are sent to disk but does not wait on them
C
Chris Mason 已提交
645
 */
646
int btrfs_write_marked_extents(struct btrfs_root *root,
647
			       struct extent_io_tree *dirty_pages, int mark)
C
Chris Mason 已提交
648
{
649
	int err = 0;
650
	int werr = 0;
J
Josef Bacik 已提交
651
	struct address_space *mapping = root->fs_info->btree_inode->i_mapping;
652
	u64 start = 0;
653
	u64 end;
654

J
Josef Bacik 已提交
655 656 657 658 659 660 661 662 663
	while (!find_first_extent_bit(dirty_pages, start, &start, &end,
				      mark)) {
		convert_extent_bit(dirty_pages, start, end, EXTENT_NEED_WAIT, mark,
				   GFP_NOFS);
		err = filemap_fdatawrite_range(mapping, start, end);
		if (err)
			werr = err;
		cond_resched();
		start = end + 1;
664
	}
665 666 667 668 669 670 671 672 673 674 675 676
	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,
677
			      struct extent_io_tree *dirty_pages, int mark)
678 679 680
{
	int err = 0;
	int werr = 0;
J
Josef Bacik 已提交
681
	struct address_space *mapping = root->fs_info->btree_inode->i_mapping;
682 683
	u64 start = 0;
	u64 end;
684

J
Josef Bacik 已提交
685 686 687 688 689 690 691 692
	while (!find_first_extent_bit(dirty_pages, start, &start, &end,
				      EXTENT_NEED_WAIT)) {
		clear_extent_bits(dirty_pages, start, end, EXTENT_NEED_WAIT, GFP_NOFS);
		err = filemap_fdatawait_range(mapping, start, end);
		if (err)
			werr = err;
		cond_resched();
		start = end + 1;
693
	}
694 695 696
	if (err)
		werr = err;
	return werr;
C
Chris Mason 已提交
697 698
}

699 700 701 702 703 704
/*
 * 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,
705
				struct extent_io_tree *dirty_pages, int mark)
706 707 708 709
{
	int ret;
	int ret2;

710 711
	ret = btrfs_write_marked_extents(root, dirty_pages, mark);
	ret2 = btrfs_wait_marked_extents(root, dirty_pages, mark);
712 713 714 715 716 717

	if (ret)
		return ret;
	if (ret2)
		return ret2;
	return 0;
718 719
}

720 721 722 723 724 725 726 727 728
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,
729 730
					   &trans->transaction->dirty_pages,
					   EXTENT_DIRTY);
731 732
}

C
Chris Mason 已提交
733 734 735 736 737 738 739 740 741 742
/*
 * 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.
 */
743 744
static int update_cowonly_root(struct btrfs_trans_handle *trans,
			       struct btrfs_root *root)
C
Chris Mason 已提交
745 746
{
	int ret;
747
	u64 old_root_bytenr;
748
	u64 old_root_used;
749
	struct btrfs_root *tree_root = root->fs_info->tree_root;
C
Chris Mason 已提交
750

751
	old_root_used = btrfs_root_used(&root->root_item);
752
	btrfs_write_dirty_block_groups(trans, root);
753

C
Chris Mason 已提交
754
	while (1) {
755
		old_root_bytenr = btrfs_root_bytenr(&root->root_item);
756 757
		if (old_root_bytenr == root->node->start &&
		    old_root_used == btrfs_root_used(&root->root_item))
C
Chris Mason 已提交
758
			break;
759

760
		btrfs_set_root_node(&root->root_item, root->node);
C
Chris Mason 已提交
761
		ret = btrfs_update_root(trans, tree_root,
762 763
					&root->root_key,
					&root->root_item);
764 765
		if (ret)
			return ret;
766

767
		old_root_used = btrfs_root_used(&root->root_item);
768
		ret = btrfs_write_dirty_block_groups(trans, root);
769 770
		if (ret)
			return ret;
771
	}
772 773 774 775

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

776 777 778
	return 0;
}

C
Chris Mason 已提交
779 780
/*
 * update all the cowonly tree roots on disk
781 782 783 784
 *
 * 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
785
 */
786 787
static noinline int commit_cowonly_roots(struct btrfs_trans_handle *trans,
					 struct btrfs_root *root)
788 789 790
{
	struct btrfs_fs_info *fs_info = root->fs_info;
	struct list_head *next;
791
	struct extent_buffer *eb;
792
	int ret;
793

794
	ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1);
795 796
	if (ret)
		return ret;
797

798
	eb = btrfs_lock_root_node(fs_info->tree_root);
799 800
	ret = btrfs_cow_block(trans, fs_info->tree_root, eb, NULL,
			      0, &eb);
801 802
	btrfs_tree_unlock(eb);
	free_extent_buffer(eb);
803

804 805 806
	if (ret)
		return ret;

807
	ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1);
808 809
	if (ret)
		return ret;
810

811 812 813
	ret = btrfs_run_dev_stats(trans, root->fs_info);
	BUG_ON(ret);

814 815 816 817 818 819 820
	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
821
	while (!list_empty(&fs_info->dirty_cowonly_roots)) {
822 823 824
		next = fs_info->dirty_cowonly_roots.next;
		list_del_init(next);
		root = list_entry(next, struct btrfs_root, dirty_list);
825

826 827 828
		ret = update_cowonly_root(trans, root);
		if (ret)
			return ret;
C
Chris Mason 已提交
829
	}
830 831 832 833 834

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

C
Chris Mason 已提交
835 836 837
	return 0;
}

C
Chris Mason 已提交
838 839 840 841 842
/*
 * 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
 */
843
int btrfs_add_dead_root(struct btrfs_root *root)
844
{
J
Josef Bacik 已提交
845
	spin_lock(&root->fs_info->trans_lock);
846
	list_add(&root->root_list, &root->fs_info->dead_roots);
J
Josef Bacik 已提交
847
	spin_unlock(&root->fs_info->trans_lock);
848 849 850
	return 0;
}

C
Chris Mason 已提交
851
/*
852
 * update all the cowonly tree roots on disk
C
Chris Mason 已提交
853
 */
854 855
static noinline int commit_fs_roots(struct btrfs_trans_handle *trans,
				    struct btrfs_root *root)
856 857
{
	struct btrfs_root *gang[8];
858
	struct btrfs_fs_info *fs_info = root->fs_info;
859 860
	int i;
	int ret;
861 862
	int err = 0;

J
Josef Bacik 已提交
863
	spin_lock(&fs_info->fs_roots_radix_lock);
C
Chris Mason 已提交
864
	while (1) {
865 866
		ret = radix_tree_gang_lookup_tag(&fs_info->fs_roots_radix,
						 (void **)gang, 0,
867 868 869 870 871 872
						 ARRAY_SIZE(gang),
						 BTRFS_ROOT_TRANS_TAG);
		if (ret == 0)
			break;
		for (i = 0; i < ret; i++) {
			root = gang[i];
873 874 875
			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
876
			spin_unlock(&fs_info->fs_roots_radix_lock);
Y
Yan Zheng 已提交
877

878
			btrfs_free_log(trans, root);
879
			btrfs_update_reloc_root(trans, root);
880
			btrfs_orphan_commit_root(trans, root);
881

882 883
			btrfs_save_ino_cache(root, trans);

884 885 886 887
			/* see comments in should_cow_block() */
			root->force_cow = 0;
			smp_wmb();

888
			if (root->commit_root != root->node) {
889
				mutex_lock(&root->fs_commit_mutex);
J
Josef Bacik 已提交
890
				switch_commit_root(root);
891 892 893
				btrfs_unpin_free_ino(root);
				mutex_unlock(&root->fs_commit_mutex);

894 895 896
				btrfs_set_root_node(&root->root_item,
						    root->node);
			}
897 898

			err = btrfs_update_root(trans, fs_info->tree_root,
899 900
						&root->root_key,
						&root->root_item);
J
Josef Bacik 已提交
901
			spin_lock(&fs_info->fs_roots_radix_lock);
902 903
			if (err)
				break;
904 905
		}
	}
J
Josef Bacik 已提交
906
	spin_unlock(&fs_info->fs_roots_radix_lock);
907
	return err;
908 909
}

C
Chris Mason 已提交
910 911 912 913
/*
 * defrag a given btree.  If cacheonly == 1, this won't read from the disk,
 * otherwise every leaf in the btree is read and defragged.
 */
914 915 916 917
int btrfs_defrag_root(struct btrfs_root *root, int cacheonly)
{
	struct btrfs_fs_info *info = root->fs_info;
	struct btrfs_trans_handle *trans;
918
	int ret;
919
	unsigned long nr;
920

921
	if (xchg(&root->defrag_running, 1))
922
		return 0;
923

924
	while (1) {
925 926 927 928
		trans = btrfs_start_transaction(root, 0);
		if (IS_ERR(trans))
			return PTR_ERR(trans);

929
		ret = btrfs_defrag_leaves(trans, root, cacheonly);
930

931
		nr = trans->blocks_used;
932
		btrfs_end_transaction(trans, root);
933
		btrfs_btree_balance_dirty(info->tree_root, nr);
934 935
		cond_resched();

936
		if (btrfs_fs_closing(root->fs_info) || ret != -EAGAIN)
937 938 939
			break;
	}
	root->defrag_running = 0;
940
	return ret;
941 942
}

C
Chris Mason 已提交
943 944 945 946
/*
 * new snapshots need to be created at a very specific time in the
 * transaction commit.  This does the actual creation
 */
947
static noinline int create_pending_snapshot(struct btrfs_trans_handle *trans,
948 949 950 951
				   struct btrfs_fs_info *fs_info,
				   struct btrfs_pending_snapshot *pending)
{
	struct btrfs_key key;
952
	struct btrfs_root_item *new_root_item;
953 954
	struct btrfs_root *tree_root = fs_info->tree_root;
	struct btrfs_root *root = pending->root;
955
	struct btrfs_root *parent_root;
L
Liu Bo 已提交
956
	struct btrfs_block_rsv *rsv;
957
	struct inode *parent_inode;
958
	struct dentry *parent;
959
	struct dentry *dentry;
960
	struct extent_buffer *tmp;
961
	struct extent_buffer *old;
962
	struct timespec cur_time = CURRENT_TIME;
963
	int ret;
964
	u64 to_reserve = 0;
965
	u64 index = 0;
966
	u64 objectid;
L
Li Zefan 已提交
967
	u64 root_flags;
968
	uuid_le new_uuid;
969

970 971
	new_root_item = kmalloc(sizeof(*new_root_item), GFP_NOFS);
	if (!new_root_item) {
972
		ret = pending->error = -ENOMEM;
973
		goto root_item_alloc_fail;
974
	}
975

976
	ret = btrfs_find_free_objectid(tree_root, &objectid);
977 978
	if (ret) {
		pending->error = ret;
979
		goto no_free_objectid;
980
	}
981

982
	btrfs_reloc_pre_snapshot(trans, pending, &to_reserve);
983 984

	if (to_reserve > 0) {
985 986
		ret = btrfs_block_rsv_add_noflush(root, &pending->block_rsv,
						  to_reserve);
987 988
		if (ret) {
			pending->error = ret;
989
			goto no_free_objectid;
990 991 992
		}
	}

A
Arne Jansen 已提交
993 994 995 996
	ret = btrfs_qgroup_inherit(trans, fs_info, root->root_key.objectid,
				   objectid, pending->inherit);
	if (ret) {
		pending->error = ret;
997
		goto no_free_objectid;
A
Arne Jansen 已提交
998 999
	}

1000
	key.objectid = objectid;
1001 1002
	key.offset = (u64)-1;
	key.type = BTRFS_ROOT_ITEM_KEY;
1003

1004
	rsv = trans->block_rsv;
1005
	trans->block_rsv = &pending->block_rsv;
1006

1007
	dentry = pending->dentry;
1008 1009
	parent = dget_parent(dentry);
	parent_inode = parent->d_inode;
1010
	parent_root = BTRFS_I(parent_inode)->root;
C
Chris Mason 已提交
1011
	record_root_in_trans(trans, parent_root);
1012

1013 1014 1015
	/*
	 * insert the directory item
	 */
1016
	ret = btrfs_set_inode_index(parent_inode, &index);
1017
	BUG_ON(ret); /* -ENOMEM */
1018
	ret = btrfs_insert_dir_item(trans, parent_root,
1019
				dentry->d_name.name, dentry->d_name.len,
1020
				parent_inode, &key,
1021
				BTRFS_FT_DIR, index);
1022
	if (ret == -EEXIST) {
1023 1024
		pending->error = -EEXIST;
		goto fail;
1025
	} else if (ret) {
1026
		goto abort_trans;
1027
	}
1028

1029 1030
	btrfs_i_size_write(parent_inode, parent_inode->i_size +
					 dentry->d_name.len * 2);
1031
	parent_inode->i_mtime = parent_inode->i_ctime = CURRENT_TIME;
1032
	ret = btrfs_update_inode(trans, parent_root, parent_inode);
1033
	if (ret)
1034
		goto abort_trans;
1035

1036 1037 1038 1039 1040 1041 1042
	/*
	 * 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);
1043 1044
	if (ret)	/* Transaction aborted */
		goto abort_trans;
1045

C
Chris Mason 已提交
1046
	record_root_in_trans(trans, root);
1047 1048
	btrfs_set_root_last_snapshot(&root->root_item, trans->transid);
	memcpy(new_root_item, &root->root_item, sizeof(*new_root_item));
1049
	btrfs_check_and_init_root_item(new_root_item);
1050

L
Li Zefan 已提交
1051 1052 1053 1054 1055 1056 1057
	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);

1058 1059 1060 1061 1062 1063 1064
	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);
1065
	new_root_item->otime.nsec = cpu_to_le32(cur_time.tv_nsec);
1066 1067 1068 1069 1070 1071
	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);

1072
	old = btrfs_lock_root_node(root);
1073
	ret = btrfs_cow_block(trans, root, old, NULL, 0, &old);
1074 1075 1076
	if (ret) {
		btrfs_tree_unlock(old);
		free_extent_buffer(old);
1077
		goto abort_trans;
1078
	}
1079

1080 1081
	btrfs_set_lock_blocking(old);

1082
	ret = btrfs_copy_root(trans, root, old, &tmp, objectid);
1083
	/* clean up in any case */
1084 1085
	btrfs_tree_unlock(old);
	free_extent_buffer(old);
1086
	if (ret)
1087
		goto abort_trans;
1088

1089 1090 1091 1092
	/* see comments in should_cow_block() */
	root->force_cow = 1;
	smp_wmb();

1093
	btrfs_set_root_node(new_root_item, tmp);
1094 1095 1096
	/* record when the snapshot was created in key.offset */
	key.offset = trans->transid;
	ret = btrfs_insert_root(trans, tree_root, &key, new_root_item);
1097 1098
	btrfs_tree_unlock(tmp);
	free_extent_buffer(tmp);
1099
	if (ret)
1100
		goto abort_trans;
1101

1102 1103 1104 1105
	/*
	 * insert root back/forward references
	 */
	ret = btrfs_add_root_ref(trans, tree_root, objectid,
1106
				 parent_root->root_key.objectid,
L
Li Zefan 已提交
1107
				 btrfs_ino(parent_inode), index,
1108
				 dentry->d_name.name, dentry->d_name.len);
1109
	if (ret)
1110
		goto abort_trans;
1111

1112 1113
	key.offset = (u64)-1;
	pending->snap = btrfs_read_fs_root_no_name(root->fs_info, &key);
1114 1115
	if (IS_ERR(pending->snap)) {
		ret = PTR_ERR(pending->snap);
1116
		goto abort_trans;
1117
	}
1118

1119 1120 1121
	ret = btrfs_reloc_post_snapshot(trans, pending);
	if (ret)
		goto abort_trans;
1122
fail:
1123
	dput(parent);
L
Liu Bo 已提交
1124
	trans->block_rsv = rsv;
1125 1126 1127
no_free_objectid:
	kfree(new_root_item);
root_item_alloc_fail:
1128
	btrfs_block_rsv_release(root, &pending->block_rsv, (u64)-1);
1129 1130 1131 1132 1133
	return ret;

abort_trans:
	btrfs_abort_transaction(trans, root, ret);
	goto fail;
1134 1135
}

C
Chris Mason 已提交
1136 1137 1138
/*
 * create all the snapshots we've scheduled for creation
 */
1139 1140
static noinline int create_pending_snapshots(struct btrfs_trans_handle *trans,
					     struct btrfs_fs_info *fs_info)
1141 1142 1143 1144
{
	struct btrfs_pending_snapshot *pending;
	struct list_head *head = &trans->transaction->pending_snapshots;

1145 1146
	list_for_each_entry(pending, head, list)
		create_pending_snapshot(trans, fs_info, pending);
1147 1148 1149
	return 0;
}

1150 1151 1152 1153 1154
static void update_super_roots(struct btrfs_root *root)
{
	struct btrfs_root_item *root_item;
	struct btrfs_super_block *super;

1155
	super = root->fs_info->super_copy;
1156 1157 1158 1159 1160 1161 1162 1163 1164 1165

	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;
1166
	if (btrfs_test_opt(root, SPACE_CACHE))
1167
		super->cache_generation = root_item->generation;
1168 1169
}

1170 1171 1172
int btrfs_transaction_in_commit(struct btrfs_fs_info *info)
{
	int ret = 0;
J
Josef Bacik 已提交
1173
	spin_lock(&info->trans_lock);
1174 1175
	if (info->running_transaction)
		ret = info->running_transaction->in_commit;
J
Josef Bacik 已提交
1176
	spin_unlock(&info->trans_lock);
1177 1178 1179
	return ret;
}

1180 1181 1182
int btrfs_transaction_blocked(struct btrfs_fs_info *info)
{
	int ret = 0;
J
Josef Bacik 已提交
1183
	spin_lock(&info->trans_lock);
1184 1185
	if (info->running_transaction)
		ret = info->running_transaction->blocked;
J
Josef Bacik 已提交
1186
	spin_unlock(&info->trans_lock);
1187 1188 1189
	return ret;
}

S
Sage Weil 已提交
1190 1191 1192 1193 1194 1195 1196
/*
 * 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
1197
	wait_event(root->fs_info->transaction_blocked_wait, trans->in_commit);
S
Sage Weil 已提交
1198 1199 1200 1201 1202 1203 1204 1205 1206
}

/*
 * 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
1207 1208
	wait_event(root->fs_info->transaction_wait,
		   trans->commit_done || (trans->in_commit && !trans->blocked));
S
Sage Weil 已提交
1209 1210 1211 1212 1213 1214 1215 1216 1217 1218 1219 1220 1221 1222 1223 1224 1225
}

/*
 * 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;
	struct delayed_work work;
};

static void do_async_commit(struct work_struct *work)
{
	struct btrfs_async_commit *ac =
		container_of(work, struct btrfs_async_commit, work.work);

1226 1227 1228 1229 1230 1231 1232 1233
	/*
	 * We've got freeze protection passed with the transaction.
	 * Tell lockdep about it.
	 */
	rwsem_acquire_read(
		&ac->root->fs_info->sb->s_writers.lock_map[SB_FREEZE_FS-1],
		0, 1, _THIS_IP_);

1234 1235
	current->journal_info = ac->newtrans;

S
Sage Weil 已提交
1236 1237 1238 1239 1240 1241 1242 1243 1244 1245 1246 1247
	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
1248 1249
	if (!ac)
		return -ENOMEM;
S
Sage Weil 已提交
1250 1251 1252

	INIT_DELAYED_WORK(&ac->work, do_async_commit);
	ac->root = root;
1253
	ac->newtrans = btrfs_join_transaction(root);
1254 1255 1256 1257 1258
	if (IS_ERR(ac->newtrans)) {
		int err = PTR_ERR(ac->newtrans);
		kfree(ac);
		return err;
	}
S
Sage Weil 已提交
1259 1260 1261

	/* take transaction reference */
	cur_trans = trans->transaction;
1262
	atomic_inc(&cur_trans->use_count);
S
Sage Weil 已提交
1263 1264

	btrfs_end_transaction(trans, root);
1265 1266 1267 1268 1269 1270 1271 1272

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

S
Sage Weil 已提交
1273 1274 1275 1276 1277 1278 1279 1280
	schedule_delayed_work(&ac->work, 0);

	/* 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);

1281 1282 1283 1284
	if (current->journal_info == trans)
		current->journal_info = NULL;

	put_transaction(cur_trans);
S
Sage Weil 已提交
1285 1286 1287
	return 0;
}

1288 1289

static void cleanup_transaction(struct btrfs_trans_handle *trans,
1290
				struct btrfs_root *root, int err)
1291 1292 1293 1294 1295
{
	struct btrfs_transaction *cur_trans = trans->transaction;

	WARN_ON(trans->use_count > 1);

1296 1297
	btrfs_abort_transaction(trans, root, err);

1298 1299
	spin_lock(&root->fs_info->trans_lock);
	list_del_init(&cur_trans->list);
1300 1301 1302 1303
	if (cur_trans == root->fs_info->running_transaction) {
		root->fs_info->running_transaction = NULL;
		root->fs_info->trans_no_join = 0;
	}
1304 1305 1306 1307 1308 1309 1310 1311 1312 1313 1314 1315 1316 1317 1318 1319 1320
	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);
}

S
Sage Weil 已提交
1321 1322 1323 1324 1325 1326 1327
/*
 * 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
1328 1329 1330
int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
			     struct btrfs_root *root)
{
1331
	unsigned long joined = 0;
1332
	struct btrfs_transaction *cur_trans = trans->transaction;
C
Chris Mason 已提交
1333
	struct btrfs_transaction *prev_trans = NULL;
C
Chris Mason 已提交
1334
	DEFINE_WAIT(wait);
1335
	int ret = -EIO;
1336 1337
	int should_grow = 0;
	unsigned long now = get_seconds();
1338
	int flush_on_commit = btrfs_test_opt(root, FLUSHONCOMMIT);
C
Chris Mason 已提交
1339

1340 1341
	btrfs_run_ordered_operations(root, 0);

1342 1343 1344
	if (cur_trans->aborted)
		goto cleanup_transaction;

1345 1346 1347 1348
	/* 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);
1349 1350
	if (ret)
		goto cleanup_transaction;
1351

1352 1353 1354
	btrfs_trans_release_metadata(trans, root);
	trans->block_rsv = NULL;

1355
	cur_trans = trans->transaction;
1356

1357 1358 1359 1360
	/*
	 * set the flushing flag so procs in this transaction have to
	 * start sending their work down.
	 */
1361
	cur_trans->delayed_refs.flushing = 1;
1362

1363
	ret = btrfs_run_delayed_refs(trans, root, 0);
1364 1365
	if (ret)
		goto cleanup_transaction;
1366

J
Josef Bacik 已提交
1367
	spin_lock(&cur_trans->commit_lock);
1368
	if (cur_trans->in_commit) {
J
Josef Bacik 已提交
1369
		spin_unlock(&cur_trans->commit_lock);
1370
		atomic_inc(&cur_trans->use_count);
1371
		ret = btrfs_end_transaction(trans, root);
C
Chris Mason 已提交
1372

1373
		wait_for_commit(root, cur_trans);
1374

C
Chris Mason 已提交
1375
		put_transaction(cur_trans);
1376

1377
		return ret;
C
Chris Mason 已提交
1378
	}
1379

C
Chris Mason 已提交
1380
	trans->transaction->in_commit = 1;
1381
	trans->transaction->blocked = 1;
J
Josef Bacik 已提交
1382
	spin_unlock(&cur_trans->commit_lock);
S
Sage Weil 已提交
1383 1384
	wake_up(&root->fs_info->transaction_blocked_wait);

J
Josef Bacik 已提交
1385
	spin_lock(&root->fs_info->trans_lock);
C
Chris Mason 已提交
1386 1387 1388 1389
	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) {
1390
			atomic_inc(&prev_trans->use_count);
J
Josef Bacik 已提交
1391
			spin_unlock(&root->fs_info->trans_lock);
C
Chris Mason 已提交
1392 1393 1394

			wait_for_commit(root, prev_trans);

1395
			put_transaction(prev_trans);
J
Josef Bacik 已提交
1396 1397
		} else {
			spin_unlock(&root->fs_info->trans_lock);
C
Chris Mason 已提交
1398
		}
J
Josef Bacik 已提交
1399 1400
	} else {
		spin_unlock(&root->fs_info->trans_lock);
C
Chris Mason 已提交
1401
	}
1402

1403 1404
	if (!btrfs_test_opt(root, SSD) &&
	    (now < cur_trans->start_time || now - cur_trans->start_time < 1))
1405 1406
		should_grow = 1;

1407
	do {
1408
		int snap_pending = 0;
J
Josef Bacik 已提交
1409

1410
		joined = cur_trans->num_joined;
1411 1412 1413
		if (!list_empty(&trans->transaction->pending_snapshots))
			snap_pending = 1;

C
Chris Mason 已提交
1414
		WARN_ON(cur_trans != trans->transaction);
1415

1416
		if (flush_on_commit || snap_pending) {
Y
Yan, Zheng 已提交
1417
			btrfs_start_delalloc_inodes(root, 1);
1418
			btrfs_wait_ordered_extents(root, 0, 1);
1419 1420
		}

1421
		ret = btrfs_run_delayed_items(trans, root);
1422 1423
		if (ret)
			goto cleanup_transaction;
1424

1425 1426 1427 1428 1429 1430 1431
		/*
		 * 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);

1432 1433 1434 1435 1436 1437 1438 1439 1440
		/*
		 * 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);

1441 1442 1443
		prepare_to_wait(&cur_trans->writer_wait, &wait,
				TASK_UNINTERRUPTIBLE);

1444
		if (atomic_read(&cur_trans->num_writers) > 1)
1445 1446 1447
			schedule_timeout(MAX_SCHEDULE_TIMEOUT);
		else if (should_grow)
			schedule_timeout(1);
1448 1449

		finish_wait(&cur_trans->writer_wait, &wait);
1450
	} while (atomic_read(&cur_trans->num_writers) > 1 ||
1451
		 (should_grow && cur_trans->num_joined != joined));
1452

1453 1454 1455 1456 1457 1458 1459 1460 1461 1462 1463
	/*
	 * 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);

C
Chris Mason 已提交
1464 1465 1466 1467 1468 1469 1470
	/*
	 * 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);

1471
	ret = btrfs_run_delayed_items(trans, root);
1472 1473 1474 1475
	if (ret) {
		mutex_unlock(&root->fs_info->reloc_mutex);
		goto cleanup_transaction;
	}
1476

1477
	ret = create_pending_snapshots(trans, root->fs_info);
1478 1479 1480 1481
	if (ret) {
		mutex_unlock(&root->fs_info->reloc_mutex);
		goto cleanup_transaction;
	}
1482

1483
	ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1);
1484 1485 1486 1487
	if (ret) {
		mutex_unlock(&root->fs_info->reloc_mutex);
		goto cleanup_transaction;
	}
1488

1489 1490 1491 1492 1493 1494
	/*
	 * 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
1495
	WARN_ON(cur_trans != trans->transaction);
C
Chris Mason 已提交
1496

A
Arne Jansen 已提交
1497
	btrfs_scrub_pause(root);
1498 1499 1500 1501 1502 1503 1504 1505 1506 1507 1508 1509 1510 1511 1512
	/* 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);

1513
	ret = commit_fs_roots(trans, root);
1514 1515
	if (ret) {
		mutex_unlock(&root->fs_info->tree_log_mutex);
1516
		mutex_unlock(&root->fs_info->reloc_mutex);
1517 1518
		goto cleanup_transaction;
	}
1519

1520
	/* commit_fs_roots gets rid of all the tree log roots, it is now
1521 1522 1523 1524
	 * safe to free the root of tree log roots
	 */
	btrfs_free_log_root_tree(trans, root->fs_info);

1525
	ret = commit_cowonly_roots(trans, root);
1526 1527
	if (ret) {
		mutex_unlock(&root->fs_info->tree_log_mutex);
1528
		mutex_unlock(&root->fs_info->reloc_mutex);
1529 1530
		goto cleanup_transaction;
	}
1531

1532 1533
	btrfs_prepare_extent_commit(trans, root);

C
Chris Mason 已提交
1534
	cur_trans = root->fs_info->running_transaction;
1535 1536 1537

	btrfs_set_root_node(&root->fs_info->tree_root->root_item,
			    root->fs_info->tree_root->node);
J
Josef Bacik 已提交
1538
	switch_commit_root(root->fs_info->tree_root);
1539 1540 1541

	btrfs_set_root_node(&root->fs_info->chunk_root->root_item,
			    root->fs_info->chunk_root->node);
J
Josef Bacik 已提交
1542
	switch_commit_root(root->fs_info->chunk_root);
1543

1544
	assert_qgroups_uptodate(trans);
1545
	update_super_roots(root);
1546 1547

	if (!root->fs_info->log_root_recovering) {
1548 1549
		btrfs_set_super_log_root(root->fs_info->super_copy, 0);
		btrfs_set_super_log_root_level(root->fs_info->super_copy, 0);
1550 1551
	}

1552 1553
	memcpy(root->fs_info->super_for_commit, root->fs_info->super_copy,
	       sizeof(*root->fs_info->super_copy));
C
Chris Mason 已提交
1554

1555
	trans->transaction->blocked = 0;
J
Josef Bacik 已提交
1556 1557 1558 1559
	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
1560
	mutex_unlock(&root->fs_info->reloc_mutex);
1561

1562
	wake_up(&root->fs_info->transaction_wait);
1563

C
Chris Mason 已提交
1564
	ret = btrfs_write_and_wait_transaction(trans, root);
1565 1566 1567 1568 1569 1570 1571 1572 1573 1574 1575 1576
	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;
	}
1577

1578 1579 1580 1581 1582 1583
	/*
	 * the super is written, we can safely allow the tree-loggers
	 * to go about their business
	 */
	mutex_unlock(&root->fs_info->tree_log_mutex);

1584
	btrfs_finish_extent_commit(trans, root);
1585

C
Chris Mason 已提交
1586
	cur_trans->commit_done = 1;
1587

1588
	root->fs_info->last_trans_committed = cur_trans->transid;
J
Josef Bacik 已提交
1589

C
Chris Mason 已提交
1590
	wake_up(&cur_trans->commit_wait);
1591

J
Josef Bacik 已提交
1592
	spin_lock(&root->fs_info->trans_lock);
1593
	list_del_init(&cur_trans->list);
J
Josef Bacik 已提交
1594 1595
	spin_unlock(&root->fs_info->trans_lock);

C
Chris Mason 已提交
1596
	put_transaction(cur_trans);
C
Chris Mason 已提交
1597
	put_transaction(cur_trans);
1598

1599 1600
	sb_end_intwrite(root->fs_info->sb);

1601 1602
	trace_btrfs_transaction_commit(root);

A
Arne Jansen 已提交
1603 1604
	btrfs_scrub_continue(root);

J
Josef Bacik 已提交
1605 1606 1607
	if (current->journal_info == trans)
		current->journal_info = NULL;

C
Chris Mason 已提交
1608
	kmem_cache_free(btrfs_trans_handle_cachep, trans);
Y
Yan, Zheng 已提交
1609 1610 1611 1612

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

C
Chris Mason 已提交
1613
	return ret;
1614 1615

cleanup_transaction:
1616 1617
	btrfs_trans_release_metadata(trans, root);
	trans->block_rsv = NULL;
1618 1619 1620 1621
	btrfs_printk(root->fs_info, "Skipping commit of aborted transaction.\n");
//	WARN_ON(1);
	if (current->journal_info == trans)
		current->journal_info = NULL;
1622
	cleanup_transaction(trans, root, ret);
1623 1624

	return ret;
C
Chris Mason 已提交
1625 1626
}

C
Chris Mason 已提交
1627 1628 1629
/*
 * interface function to delete all the snapshots we have scheduled for deletion
 */
1630 1631
int btrfs_clean_old_snapshots(struct btrfs_root *root)
{
1632 1633 1634
	LIST_HEAD(list);
	struct btrfs_fs_info *fs_info = root->fs_info;

J
Josef Bacik 已提交
1635
	spin_lock(&fs_info->trans_lock);
1636
	list_splice_init(&fs_info->dead_roots, &list);
J
Josef Bacik 已提交
1637
	spin_unlock(&fs_info->trans_lock);
1638

1639
	while (!list_empty(&list)) {
1640 1641
		int ret;

1642
		root = list_entry(list.next, struct btrfs_root, root_list);
1643 1644
		list_del(&root->root_list);

1645 1646
		btrfs_kill_all_delayed_nodes(root);

1647 1648
		if (btrfs_header_backref_rev(root->node) <
		    BTRFS_MIXED_BACKREF_REV)
1649
			ret = btrfs_drop_snapshot(root, NULL, 0, 0);
1650
		else
1651 1652
			ret =btrfs_drop_snapshot(root, NULL, 1, 0);
		BUG_ON(ret < 0);
1653 1654 1655
	}
	return 0;
}