transaction.c 40.3 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 "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 (root->fs_info->fs_state & BTRFS_SUPER_FLAG_ERROR) {
		spin_unlock(&root->fs_info->trans_lock);
		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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	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) {
		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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	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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		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->delayed_ref_updates = 0;
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	h->use_count = 1;
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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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	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)
377
{
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	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;
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	struct btrfs_block_rsv *rsv = trans->block_rsv;
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	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;

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	/*
	 * We need to do this in case we're deleting csums so the global block
	 * rsv get's used instead of the csum block rsv.
	 */
	trans->block_rsv = NULL;

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	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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	trans->block_rsv = rsv;

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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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{
502
	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;
	}

512
	btrfs_trans_release_metadata(trans, root);
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	trans->block_rsv = NULL;
514
	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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	if (lock && !atomic_read(&root->fs_info->open_ioctl_trans) &&
	    should_end_transaction(trans, root)) {
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		trans->transaction->blocked = 1;
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		smp_wmb();
	}
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533
	if (lock && cur_trans->blocked && !cur_trans->in_commit) {
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		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++;
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			return btrfs_commit_transaction(trans, root);
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		} else {
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			wake_up_process(info->transaction_kthread);
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		}
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	}

	WARN_ON(cur_trans != info->running_transaction);
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	WARN_ON(atomic_read(&cur_trans->num_writers) < 1);
	atomic_dec(&cur_trans->num_writers);
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	smp_mb();
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	if (waitqueue_active(&cur_trans->writer_wait))
		wake_up(&cur_trans->writer_wait);
	put_transaction(cur_trans);
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555 556 557

	if (current->journal_info == trans)
		current->journal_info = NULL;
558

Y
Yan, Zheng 已提交
559 560 561
	if (throttle)
		btrfs_run_delayed_iputs(root);

562 563
	if (trans->aborted ||
	    root->fs_info->fs_state & BTRFS_SUPER_FLAG_ERROR) {
564
		err = -EIO;
565 566
	}

567 568 569
	memset(trans, 0, sizeof(*trans));
	kmem_cache_free(btrfs_trans_handle_cachep, trans);
	return err;
C
Chris Mason 已提交
570 571
}

572 573 574
int btrfs_end_transaction(struct btrfs_trans_handle *trans,
			  struct btrfs_root *root)
{
575 576 577 578 579 580
	int ret;

	ret = __btrfs_end_transaction(trans, root, 0, 1);
	if (ret)
		return ret;
	return 0;
581 582 583 584 585
}

int btrfs_end_transaction_throttle(struct btrfs_trans_handle *trans,
				   struct btrfs_root *root)
{
586 587 588 589 590 591
	int ret;

	ret = __btrfs_end_transaction(trans, root, 1, 1);
	if (ret)
		return ret;
	return 0;
592 593 594 595 596
}

int btrfs_end_transaction_nolock(struct btrfs_trans_handle *trans,
				 struct btrfs_root *root)
{
597 598 599 600 601 602 603 604 605 606 607 608
	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);
609 610
}

C
Chris Mason 已提交
611 612 613
/*
 * 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
614
 * those extents are sent to disk but does not wait on them
C
Chris Mason 已提交
615
 */
616
int btrfs_write_marked_extents(struct btrfs_root *root,
617
			       struct extent_io_tree *dirty_pages, int mark)
C
Chris Mason 已提交
618
{
619
	int err = 0;
620
	int werr = 0;
J
Josef Bacik 已提交
621
	struct address_space *mapping = root->fs_info->btree_inode->i_mapping;
622
	u64 start = 0;
623
	u64 end;
624

J
Josef Bacik 已提交
625 626 627 628 629 630 631 632 633
	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;
634
	}
635 636 637 638 639 640 641 642 643 644 645 646
	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,
647
			      struct extent_io_tree *dirty_pages, int mark)
648 649 650
{
	int err = 0;
	int werr = 0;
J
Josef Bacik 已提交
651
	struct address_space *mapping = root->fs_info->btree_inode->i_mapping;
652 653
	u64 start = 0;
	u64 end;
654

J
Josef Bacik 已提交
655 656 657 658 659 660 661 662
	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;
663
	}
664 665 666
	if (err)
		werr = err;
	return werr;
C
Chris Mason 已提交
667 668
}

669 670 671 672 673 674
/*
 * 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,
675
				struct extent_io_tree *dirty_pages, int mark)
676 677 678 679
{
	int ret;
	int ret2;

680 681
	ret = btrfs_write_marked_extents(root, dirty_pages, mark);
	ret2 = btrfs_wait_marked_extents(root, dirty_pages, mark);
682 683 684 685 686 687

	if (ret)
		return ret;
	if (ret2)
		return ret2;
	return 0;
688 689
}

690 691 692 693 694 695 696 697 698
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,
699 700
					   &trans->transaction->dirty_pages,
					   EXTENT_DIRTY);
701 702
}

C
Chris Mason 已提交
703 704 705 706 707 708 709 710 711 712
/*
 * 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.
 */
713 714
static int update_cowonly_root(struct btrfs_trans_handle *trans,
			       struct btrfs_root *root)
C
Chris Mason 已提交
715 716
{
	int ret;
717
	u64 old_root_bytenr;
718
	u64 old_root_used;
719
	struct btrfs_root *tree_root = root->fs_info->tree_root;
C
Chris Mason 已提交
720

721
	old_root_used = btrfs_root_used(&root->root_item);
722
	btrfs_write_dirty_block_groups(trans, root);
723

C
Chris Mason 已提交
724
	while (1) {
725
		old_root_bytenr = btrfs_root_bytenr(&root->root_item);
726 727
		if (old_root_bytenr == root->node->start &&
		    old_root_used == btrfs_root_used(&root->root_item))
C
Chris Mason 已提交
728
			break;
729

730
		btrfs_set_root_node(&root->root_item, root->node);
C
Chris Mason 已提交
731
		ret = btrfs_update_root(trans, tree_root,
732 733
					&root->root_key,
					&root->root_item);
734 735
		if (ret)
			return ret;
736

737
		old_root_used = btrfs_root_used(&root->root_item);
738
		ret = btrfs_write_dirty_block_groups(trans, root);
739 740
		if (ret)
			return ret;
741
	}
742 743 744 745

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

746 747 748
	return 0;
}

C
Chris Mason 已提交
749 750
/*
 * update all the cowonly tree roots on disk
751 752 753 754
 *
 * 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
755
 */
756 757
static noinline int commit_cowonly_roots(struct btrfs_trans_handle *trans,
					 struct btrfs_root *root)
758 759 760
{
	struct btrfs_fs_info *fs_info = root->fs_info;
	struct list_head *next;
761
	struct extent_buffer *eb;
762
	int ret;
763

764
	ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1);
765 766
	if (ret)
		return ret;
767

768
	eb = btrfs_lock_root_node(fs_info->tree_root);
769 770
	ret = btrfs_cow_block(trans, fs_info->tree_root, eb, NULL,
			      0, &eb);
771 772
	btrfs_tree_unlock(eb);
	free_extent_buffer(eb);
773

774 775 776
	if (ret)
		return ret;

777
	ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1);
778 779
	if (ret)
		return ret;
780

781 782 783
	ret = btrfs_run_dev_stats(trans, root->fs_info);
	BUG_ON(ret);

C
Chris Mason 已提交
784
	while (!list_empty(&fs_info->dirty_cowonly_roots)) {
785 786 787
		next = fs_info->dirty_cowonly_roots.next;
		list_del_init(next);
		root = list_entry(next, struct btrfs_root, dirty_list);
788

789 790 791
		ret = update_cowonly_root(trans, root);
		if (ret)
			return ret;
C
Chris Mason 已提交
792
	}
793 794 795 796 797

	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
798 799 800
	return 0;
}

C
Chris Mason 已提交
801 802 803 804 805
/*
 * 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
 */
806
int btrfs_add_dead_root(struct btrfs_root *root)
807
{
J
Josef Bacik 已提交
808
	spin_lock(&root->fs_info->trans_lock);
809
	list_add(&root->root_list, &root->fs_info->dead_roots);
J
Josef Bacik 已提交
810
	spin_unlock(&root->fs_info->trans_lock);
811 812 813
	return 0;
}

C
Chris Mason 已提交
814
/*
815
 * update all the cowonly tree roots on disk
C
Chris Mason 已提交
816
 */
817 818
static noinline int commit_fs_roots(struct btrfs_trans_handle *trans,
				    struct btrfs_root *root)
819 820
{
	struct btrfs_root *gang[8];
821
	struct btrfs_fs_info *fs_info = root->fs_info;
822 823
	int i;
	int ret;
824 825
	int err = 0;

J
Josef Bacik 已提交
826
	spin_lock(&fs_info->fs_roots_radix_lock);
C
Chris Mason 已提交
827
	while (1) {
828 829
		ret = radix_tree_gang_lookup_tag(&fs_info->fs_roots_radix,
						 (void **)gang, 0,
830 831 832 833 834 835
						 ARRAY_SIZE(gang),
						 BTRFS_ROOT_TRANS_TAG);
		if (ret == 0)
			break;
		for (i = 0; i < ret; i++) {
			root = gang[i];
836 837 838
			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
839
			spin_unlock(&fs_info->fs_roots_radix_lock);
Y
Yan Zheng 已提交
840

841
			btrfs_free_log(trans, root);
842
			btrfs_update_reloc_root(trans, root);
843
			btrfs_orphan_commit_root(trans, root);
844

845 846
			btrfs_save_ino_cache(root, trans);

847 848 849 850
			/* see comments in should_cow_block() */
			root->force_cow = 0;
			smp_wmb();

851
			if (root->commit_root != root->node) {
852
				mutex_lock(&root->fs_commit_mutex);
J
Josef Bacik 已提交
853
				switch_commit_root(root);
854 855 856
				btrfs_unpin_free_ino(root);
				mutex_unlock(&root->fs_commit_mutex);

857 858 859
				btrfs_set_root_node(&root->root_item,
						    root->node);
			}
860 861

			err = btrfs_update_root(trans, fs_info->tree_root,
862 863
						&root->root_key,
						&root->root_item);
J
Josef Bacik 已提交
864
			spin_lock(&fs_info->fs_roots_radix_lock);
865 866
			if (err)
				break;
867 868
		}
	}
J
Josef Bacik 已提交
869
	spin_unlock(&fs_info->fs_roots_radix_lock);
870
	return err;
871 872
}

C
Chris Mason 已提交
873 874 875 876
/*
 * defrag a given btree.  If cacheonly == 1, this won't read from the disk,
 * otherwise every leaf in the btree is read and defragged.
 */
877 878 879 880
int btrfs_defrag_root(struct btrfs_root *root, int cacheonly)
{
	struct btrfs_fs_info *info = root->fs_info;
	struct btrfs_trans_handle *trans;
881
	int ret;
882
	unsigned long nr;
883

884
	if (xchg(&root->defrag_running, 1))
885
		return 0;
886

887
	while (1) {
888 889 890 891
		trans = btrfs_start_transaction(root, 0);
		if (IS_ERR(trans))
			return PTR_ERR(trans);

892
		ret = btrfs_defrag_leaves(trans, root, cacheonly);
893

894
		nr = trans->blocks_used;
895
		btrfs_end_transaction(trans, root);
896
		btrfs_btree_balance_dirty(info->tree_root, nr);
897 898
		cond_resched();

899
		if (btrfs_fs_closing(root->fs_info) || ret != -EAGAIN)
900 901 902
			break;
	}
	root->defrag_running = 0;
903
	return ret;
904 905
}

C
Chris Mason 已提交
906 907 908 909
/*
 * new snapshots need to be created at a very specific time in the
 * transaction commit.  This does the actual creation
 */
910
static noinline int create_pending_snapshot(struct btrfs_trans_handle *trans,
911 912 913 914
				   struct btrfs_fs_info *fs_info,
				   struct btrfs_pending_snapshot *pending)
{
	struct btrfs_key key;
915
	struct btrfs_root_item *new_root_item;
916 917
	struct btrfs_root *tree_root = fs_info->tree_root;
	struct btrfs_root *root = pending->root;
918
	struct btrfs_root *parent_root;
L
Liu Bo 已提交
919
	struct btrfs_block_rsv *rsv;
920
	struct inode *parent_inode;
921
	struct dentry *parent;
922
	struct dentry *dentry;
923
	struct extent_buffer *tmp;
924
	struct extent_buffer *old;
925
	int ret;
926
	u64 to_reserve = 0;
927
	u64 index = 0;
928
	u64 objectid;
L
Li Zefan 已提交
929
	u64 root_flags;
930

L
Liu Bo 已提交
931 932
	rsv = trans->block_rsv;

933 934
	new_root_item = kmalloc(sizeof(*new_root_item), GFP_NOFS);
	if (!new_root_item) {
935
		ret = pending->error = -ENOMEM;
936 937
		goto fail;
	}
938

939
	ret = btrfs_find_free_objectid(tree_root, &objectid);
940 941
	if (ret) {
		pending->error = ret;
942
		goto fail;
943
	}
944

945
	btrfs_reloc_pre_snapshot(trans, pending, &to_reserve);
946 947

	if (to_reserve > 0) {
948 949
		ret = btrfs_block_rsv_add_noflush(root, &pending->block_rsv,
						  to_reserve);
950 951 952 953 954 955
		if (ret) {
			pending->error = ret;
			goto fail;
		}
	}

956
	key.objectid = objectid;
957 958
	key.offset = (u64)-1;
	key.type = BTRFS_ROOT_ITEM_KEY;
959

960
	trans->block_rsv = &pending->block_rsv;
961

962
	dentry = pending->dentry;
963 964
	parent = dget_parent(dentry);
	parent_inode = parent->d_inode;
965
	parent_root = BTRFS_I(parent_inode)->root;
C
Chris Mason 已提交
966
	record_root_in_trans(trans, parent_root);
967

968 969 970
	/*
	 * insert the directory item
	 */
971
	ret = btrfs_set_inode_index(parent_inode, &index);
972
	BUG_ON(ret); /* -ENOMEM */
973
	ret = btrfs_insert_dir_item(trans, parent_root,
974
				dentry->d_name.name, dentry->d_name.len,
975
				parent_inode, &key,
976
				BTRFS_FT_DIR, index);
977
	if (ret == -EEXIST) {
978 979 980
		pending->error = -EEXIST;
		dput(parent);
		goto fail;
981 982 983
	} else if (ret) {
		goto abort_trans_dput;
	}
984

985 986
	btrfs_i_size_write(parent_inode, parent_inode->i_size +
					 dentry->d_name.len * 2);
987
	ret = btrfs_update_inode(trans, parent_root, parent_inode);
988
	if (ret)
989
		goto abort_trans_dput;
990

991 992 993 994 995 996 997
	/*
	 * 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);
998 999
	if (ret) { /* Transaction aborted */
		dput(parent);
1000
		goto fail;
1001
	}
1002

C
Chris Mason 已提交
1003
	record_root_in_trans(trans, root);
1004 1005
	btrfs_set_root_last_snapshot(&root->root_item, trans->transid);
	memcpy(new_root_item, &root->root_item, sizeof(*new_root_item));
1006
	btrfs_check_and_init_root_item(new_root_item);
1007

L
Li Zefan 已提交
1008 1009 1010 1011 1012 1013 1014
	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);

1015
	old = btrfs_lock_root_node(root);
1016
	ret = btrfs_cow_block(trans, root, old, NULL, 0, &old);
1017 1018 1019 1020 1021
	if (ret) {
		btrfs_tree_unlock(old);
		free_extent_buffer(old);
		goto abort_trans_dput;
	}
1022

1023 1024
	btrfs_set_lock_blocking(old);

1025
	ret = btrfs_copy_root(trans, root, old, &tmp, objectid);
1026
	/* clean up in any case */
1027 1028
	btrfs_tree_unlock(old);
	free_extent_buffer(old);
1029 1030
	if (ret)
		goto abort_trans_dput;
1031

1032 1033 1034 1035
	/* see comments in should_cow_block() */
	root->force_cow = 1;
	smp_wmb();

1036
	btrfs_set_root_node(new_root_item, tmp);
1037 1038 1039
	/* record when the snapshot was created in key.offset */
	key.offset = trans->transid;
	ret = btrfs_insert_root(trans, tree_root, &key, new_root_item);
1040 1041
	btrfs_tree_unlock(tmp);
	free_extent_buffer(tmp);
1042
	if (ret)
1043
		goto abort_trans_dput;
1044

1045 1046 1047 1048
	/*
	 * insert root back/forward references
	 */
	ret = btrfs_add_root_ref(trans, tree_root, objectid,
1049
				 parent_root->root_key.objectid,
L
Li Zefan 已提交
1050
				 btrfs_ino(parent_inode), index,
1051
				 dentry->d_name.name, dentry->d_name.len);
1052
	dput(parent);
1053 1054
	if (ret)
		goto fail;
1055

1056 1057
	key.offset = (u64)-1;
	pending->snap = btrfs_read_fs_root_no_name(root->fs_info, &key);
1058 1059
	if (IS_ERR(pending->snap)) {
		ret = PTR_ERR(pending->snap);
1060
		goto abort_trans;
1061
	}
1062

1063 1064 1065 1066
	ret = btrfs_reloc_post_snapshot(trans, pending);
	if (ret)
		goto abort_trans;
	ret = 0;
1067
fail:
1068
	kfree(new_root_item);
L
Liu Bo 已提交
1069
	trans->block_rsv = rsv;
1070
	btrfs_block_rsv_release(root, &pending->block_rsv, (u64)-1);
1071 1072
	return ret;

1073 1074
abort_trans_dput:
	dput(parent);
1075 1076 1077
abort_trans:
	btrfs_abort_transaction(trans, root, ret);
	goto fail;
1078 1079
}

C
Chris Mason 已提交
1080 1081 1082
/*
 * create all the snapshots we've scheduled for creation
 */
1083 1084
static noinline int create_pending_snapshots(struct btrfs_trans_handle *trans,
					     struct btrfs_fs_info *fs_info)
1085 1086 1087 1088
{
	struct btrfs_pending_snapshot *pending;
	struct list_head *head = &trans->transaction->pending_snapshots;

1089 1090
	list_for_each_entry(pending, head, list)
		create_pending_snapshot(trans, fs_info, pending);
1091 1092 1093
	return 0;
}

1094 1095 1096 1097 1098
static void update_super_roots(struct btrfs_root *root)
{
	struct btrfs_root_item *root_item;
	struct btrfs_super_block *super;

1099
	super = root->fs_info->super_copy;
1100 1101 1102 1103 1104 1105 1106 1107 1108 1109

	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;
1110
	if (btrfs_test_opt(root, SPACE_CACHE))
1111
		super->cache_generation = root_item->generation;
1112 1113
}

1114 1115 1116
int btrfs_transaction_in_commit(struct btrfs_fs_info *info)
{
	int ret = 0;
J
Josef Bacik 已提交
1117
	spin_lock(&info->trans_lock);
1118 1119
	if (info->running_transaction)
		ret = info->running_transaction->in_commit;
J
Josef Bacik 已提交
1120
	spin_unlock(&info->trans_lock);
1121 1122 1123
	return ret;
}

1124 1125 1126
int btrfs_transaction_blocked(struct btrfs_fs_info *info)
{
	int ret = 0;
J
Josef Bacik 已提交
1127
	spin_lock(&info->trans_lock);
1128 1129
	if (info->running_transaction)
		ret = info->running_transaction->blocked;
J
Josef Bacik 已提交
1130
	spin_unlock(&info->trans_lock);
1131 1132 1133
	return ret;
}

S
Sage Weil 已提交
1134 1135 1136 1137 1138 1139 1140
/*
 * 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
1141
	wait_event(root->fs_info->transaction_blocked_wait, trans->in_commit);
S
Sage Weil 已提交
1142 1143 1144 1145 1146 1147 1148 1149 1150
}

/*
 * 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
1151 1152
	wait_event(root->fs_info->transaction_wait,
		   trans->commit_done || (trans->in_commit && !trans->blocked));
S
Sage Weil 已提交
1153 1154 1155 1156 1157 1158 1159 1160 1161 1162 1163 1164 1165 1166 1167 1168 1169 1170 1171 1172 1173 1174 1175 1176 1177 1178 1179 1180 1181
}

/*
 * 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);

	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
1182 1183
	if (!ac)
		return -ENOMEM;
S
Sage Weil 已提交
1184 1185 1186

	INIT_DELAYED_WORK(&ac->work, do_async_commit);
	ac->root = root;
1187
	ac->newtrans = btrfs_join_transaction(root);
1188 1189 1190 1191 1192
	if (IS_ERR(ac->newtrans)) {
		int err = PTR_ERR(ac->newtrans);
		kfree(ac);
		return err;
	}
S
Sage Weil 已提交
1193 1194 1195

	/* take transaction reference */
	cur_trans = trans->transaction;
1196
	atomic_inc(&cur_trans->use_count);
S
Sage Weil 已提交
1197 1198 1199 1200 1201 1202 1203 1204 1205 1206

	btrfs_end_transaction(trans, root);
	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);

1207 1208 1209 1210
	if (current->journal_info == trans)
		current->journal_info = NULL;

	put_transaction(cur_trans);
S
Sage Weil 已提交
1211 1212 1213
	return 0;
}

1214 1215

static void cleanup_transaction(struct btrfs_trans_handle *trans,
1216
				struct btrfs_root *root, int err)
1217 1218 1219 1220 1221
{
	struct btrfs_transaction *cur_trans = trans->transaction;

	WARN_ON(trans->use_count > 1);

1222 1223
	btrfs_abort_transaction(trans, root, err);

1224 1225
	spin_lock(&root->fs_info->trans_lock);
	list_del_init(&cur_trans->list);
1226 1227 1228 1229
	if (cur_trans == root->fs_info->running_transaction) {
		root->fs_info->running_transaction = NULL;
		root->fs_info->trans_no_join = 0;
	}
1230 1231 1232 1233 1234 1235 1236 1237 1238 1239 1240 1241 1242 1243 1244 1245 1246
	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
1247 1248 1249 1250 1251 1252 1253
/*
 * 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
1254 1255 1256
int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
			     struct btrfs_root *root)
{
1257
	unsigned long joined = 0;
1258
	struct btrfs_transaction *cur_trans = trans->transaction;
C
Chris Mason 已提交
1259
	struct btrfs_transaction *prev_trans = NULL;
C
Chris Mason 已提交
1260
	DEFINE_WAIT(wait);
1261
	int ret = -EIO;
1262 1263
	int should_grow = 0;
	unsigned long now = get_seconds();
1264
	int flush_on_commit = btrfs_test_opt(root, FLUSHONCOMMIT);
C
Chris Mason 已提交
1265

1266 1267
	btrfs_run_ordered_operations(root, 0);

1268
	btrfs_trans_release_metadata(trans, root);
1269 1270
	trans->block_rsv = NULL;

1271 1272 1273
	if (cur_trans->aborted)
		goto cleanup_transaction;

1274 1275 1276 1277
	/* 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);
1278 1279
	if (ret)
		goto cleanup_transaction;
1280

1281
	cur_trans = trans->transaction;
1282

1283 1284 1285 1286
	/*
	 * set the flushing flag so procs in this transaction have to
	 * start sending their work down.
	 */
1287
	cur_trans->delayed_refs.flushing = 1;
1288

1289
	ret = btrfs_run_delayed_refs(trans, root, 0);
1290 1291
	if (ret)
		goto cleanup_transaction;
1292

J
Josef Bacik 已提交
1293
	spin_lock(&cur_trans->commit_lock);
1294
	if (cur_trans->in_commit) {
J
Josef Bacik 已提交
1295
		spin_unlock(&cur_trans->commit_lock);
1296
		atomic_inc(&cur_trans->use_count);
1297
		ret = btrfs_end_transaction(trans, root);
C
Chris Mason 已提交
1298

1299
		wait_for_commit(root, cur_trans);
1300

C
Chris Mason 已提交
1301
		put_transaction(cur_trans);
1302

1303
		return ret;
C
Chris Mason 已提交
1304
	}
1305

C
Chris Mason 已提交
1306
	trans->transaction->in_commit = 1;
1307
	trans->transaction->blocked = 1;
J
Josef Bacik 已提交
1308
	spin_unlock(&cur_trans->commit_lock);
S
Sage Weil 已提交
1309 1310
	wake_up(&root->fs_info->transaction_blocked_wait);

J
Josef Bacik 已提交
1311
	spin_lock(&root->fs_info->trans_lock);
C
Chris Mason 已提交
1312 1313 1314 1315
	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) {
1316
			atomic_inc(&prev_trans->use_count);
J
Josef Bacik 已提交
1317
			spin_unlock(&root->fs_info->trans_lock);
C
Chris Mason 已提交
1318 1319 1320

			wait_for_commit(root, prev_trans);

1321
			put_transaction(prev_trans);
J
Josef Bacik 已提交
1322 1323
		} else {
			spin_unlock(&root->fs_info->trans_lock);
C
Chris Mason 已提交
1324
		}
J
Josef Bacik 已提交
1325 1326
	} else {
		spin_unlock(&root->fs_info->trans_lock);
C
Chris Mason 已提交
1327
	}
1328

1329 1330 1331
	if (now < cur_trans->start_time || now - cur_trans->start_time < 1)
		should_grow = 1;

1332
	do {
1333
		int snap_pending = 0;
J
Josef Bacik 已提交
1334

1335
		joined = cur_trans->num_joined;
1336 1337 1338
		if (!list_empty(&trans->transaction->pending_snapshots))
			snap_pending = 1;

C
Chris Mason 已提交
1339
		WARN_ON(cur_trans != trans->transaction);
1340

1341
		if (flush_on_commit || snap_pending) {
Y
Yan, Zheng 已提交
1342
			btrfs_start_delalloc_inodes(root, 1);
1343
			btrfs_wait_ordered_extents(root, 0, 1);
1344 1345
		}

1346
		ret = btrfs_run_delayed_items(trans, root);
1347 1348
		if (ret)
			goto cleanup_transaction;
1349

1350 1351 1352 1353 1354 1355 1356 1357 1358
		/*
		 * 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);

1359 1360 1361
		prepare_to_wait(&cur_trans->writer_wait, &wait,
				TASK_UNINTERRUPTIBLE);

1362
		if (atomic_read(&cur_trans->num_writers) > 1)
1363 1364 1365
			schedule_timeout(MAX_SCHEDULE_TIMEOUT);
		else if (should_grow)
			schedule_timeout(1);
1366 1367

		finish_wait(&cur_trans->writer_wait, &wait);
1368
	} while (atomic_read(&cur_trans->num_writers) > 1 ||
1369
		 (should_grow && cur_trans->num_joined != joined));
1370

1371 1372 1373 1374 1375 1376 1377 1378 1379 1380 1381
	/*
	 * 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
1382 1383 1384 1385 1386 1387 1388
	/*
	 * 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);

1389
	ret = btrfs_run_delayed_items(trans, root);
1390 1391 1392 1393
	if (ret) {
		mutex_unlock(&root->fs_info->reloc_mutex);
		goto cleanup_transaction;
	}
1394

1395
	ret = create_pending_snapshots(trans, root->fs_info);
1396 1397 1398 1399
	if (ret) {
		mutex_unlock(&root->fs_info->reloc_mutex);
		goto cleanup_transaction;
	}
1400

1401
	ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1);
1402 1403 1404 1405
	if (ret) {
		mutex_unlock(&root->fs_info->reloc_mutex);
		goto cleanup_transaction;
	}
1406

1407 1408 1409 1410 1411 1412
	/*
	 * 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
1413
	WARN_ON(cur_trans != trans->transaction);
C
Chris Mason 已提交
1414

A
Arne Jansen 已提交
1415
	btrfs_scrub_pause(root);
1416 1417 1418 1419 1420 1421 1422 1423 1424 1425 1426 1427 1428 1429 1430
	/* 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);

1431
	ret = commit_fs_roots(trans, root);
1432 1433
	if (ret) {
		mutex_unlock(&root->fs_info->tree_log_mutex);
1434
		mutex_unlock(&root->fs_info->reloc_mutex);
1435 1436
		goto cleanup_transaction;
	}
1437

1438
	/* commit_fs_roots gets rid of all the tree log roots, it is now
1439 1440 1441 1442
	 * safe to free the root of tree log roots
	 */
	btrfs_free_log_root_tree(trans, root->fs_info);

1443
	ret = commit_cowonly_roots(trans, root);
1444 1445
	if (ret) {
		mutex_unlock(&root->fs_info->tree_log_mutex);
1446
		mutex_unlock(&root->fs_info->reloc_mutex);
1447 1448
		goto cleanup_transaction;
	}
1449

1450 1451
	btrfs_prepare_extent_commit(trans, root);

C
Chris Mason 已提交
1452
	cur_trans = root->fs_info->running_transaction;
1453 1454 1455

	btrfs_set_root_node(&root->fs_info->tree_root->root_item,
			    root->fs_info->tree_root->node);
J
Josef Bacik 已提交
1456
	switch_commit_root(root->fs_info->tree_root);
1457 1458 1459

	btrfs_set_root_node(&root->fs_info->chunk_root->root_item,
			    root->fs_info->chunk_root->node);
J
Josef Bacik 已提交
1460
	switch_commit_root(root->fs_info->chunk_root);
1461 1462

	update_super_roots(root);
1463 1464

	if (!root->fs_info->log_root_recovering) {
1465 1466
		btrfs_set_super_log_root(root->fs_info->super_copy, 0);
		btrfs_set_super_log_root_level(root->fs_info->super_copy, 0);
1467 1468
	}

1469 1470
	memcpy(root->fs_info->super_for_commit, root->fs_info->super_copy,
	       sizeof(*root->fs_info->super_copy));
C
Chris Mason 已提交
1471

1472
	trans->transaction->blocked = 0;
J
Josef Bacik 已提交
1473 1474 1475 1476
	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
1477
	mutex_unlock(&root->fs_info->reloc_mutex);
1478

1479
	wake_up(&root->fs_info->transaction_wait);
1480

C
Chris Mason 已提交
1481
	ret = btrfs_write_and_wait_transaction(trans, root);
1482 1483 1484 1485 1486 1487 1488 1489 1490 1491 1492 1493
	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;
	}
1494

1495 1496 1497 1498 1499 1500
	/*
	 * the super is written, we can safely allow the tree-loggers
	 * to go about their business
	 */
	mutex_unlock(&root->fs_info->tree_log_mutex);

1501
	btrfs_finish_extent_commit(trans, root);
1502

C
Chris Mason 已提交
1503
	cur_trans->commit_done = 1;
1504

1505
	root->fs_info->last_trans_committed = cur_trans->transid;
J
Josef Bacik 已提交
1506

C
Chris Mason 已提交
1507
	wake_up(&cur_trans->commit_wait);
1508

J
Josef Bacik 已提交
1509
	spin_lock(&root->fs_info->trans_lock);
1510
	list_del_init(&cur_trans->list);
J
Josef Bacik 已提交
1511 1512
	spin_unlock(&root->fs_info->trans_lock);

C
Chris Mason 已提交
1513
	put_transaction(cur_trans);
C
Chris Mason 已提交
1514
	put_transaction(cur_trans);
1515

1516 1517
	trace_btrfs_transaction_commit(root);

A
Arne Jansen 已提交
1518 1519
	btrfs_scrub_continue(root);

J
Josef Bacik 已提交
1520 1521 1522
	if (current->journal_info == trans)
		current->journal_info = NULL;

C
Chris Mason 已提交
1523
	kmem_cache_free(btrfs_trans_handle_cachep, trans);
Y
Yan, Zheng 已提交
1524 1525 1526 1527

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

C
Chris Mason 已提交
1528
	return ret;
1529 1530 1531 1532 1533 1534

cleanup_transaction:
	btrfs_printk(root->fs_info, "Skipping commit of aborted transaction.\n");
//	WARN_ON(1);
	if (current->journal_info == trans)
		current->journal_info = NULL;
1535
	cleanup_transaction(trans, root, ret);
1536 1537

	return ret;
C
Chris Mason 已提交
1538 1539
}

C
Chris Mason 已提交
1540 1541 1542
/*
 * interface function to delete all the snapshots we have scheduled for deletion
 */
1543 1544
int btrfs_clean_old_snapshots(struct btrfs_root *root)
{
1545 1546 1547
	LIST_HEAD(list);
	struct btrfs_fs_info *fs_info = root->fs_info;

J
Josef Bacik 已提交
1548
	spin_lock(&fs_info->trans_lock);
1549
	list_splice_init(&fs_info->dead_roots, &list);
J
Josef Bacik 已提交
1550
	spin_unlock(&fs_info->trans_lock);
1551

1552
	while (!list_empty(&list)) {
1553 1554
		int ret;

1555
		root = list_entry(list.next, struct btrfs_root, root_list);
1556 1557
		list_del(&root->root_list);

1558 1559
		btrfs_kill_all_delayed_nodes(root);

1560 1561
		if (btrfs_header_backref_rev(root->node) <
		    BTRFS_MIXED_BACKREF_REV)
1562
			ret = btrfs_drop_snapshot(root, NULL, 0, 0);
1563
		else
1564 1565
			ret =btrfs_drop_snapshot(root, NULL, 1, 0);
		BUG_ON(ret < 0);
1566 1567 1568
	}
	return 0;
}