transaction.c 40.4 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->root = root;
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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)
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{
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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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{
383
	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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{
503
	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;
506
	int err = 0;
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	if (--trans->use_count) {
		trans->block_rsv = trans->orig_rsv;
		return 0;
	}

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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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	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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539
	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);
J
Josef Bacik 已提交
561 562 563

	if (current->journal_info == trans)
		current->journal_info = NULL;
564

Y
Yan, Zheng 已提交
565 566 567
	if (throttle)
		btrfs_run_delayed_iputs(root);

568 569
	if (trans->aborted ||
	    root->fs_info->fs_state & BTRFS_SUPER_FLAG_ERROR) {
570
		err = -EIO;
571 572
	}

573 574 575
	memset(trans, 0, sizeof(*trans));
	kmem_cache_free(btrfs_trans_handle_cachep, trans);
	return err;
C
Chris Mason 已提交
576 577
}

578 579 580
int btrfs_end_transaction(struct btrfs_trans_handle *trans,
			  struct btrfs_root *root)
{
581 582 583 584 585 586
	int ret;

	ret = __btrfs_end_transaction(trans, root, 0, 1);
	if (ret)
		return ret;
	return 0;
587 588 589 590 591
}

int btrfs_end_transaction_throttle(struct btrfs_trans_handle *trans,
				   struct btrfs_root *root)
{
592 593 594 595 596 597
	int ret;

	ret = __btrfs_end_transaction(trans, root, 1, 1);
	if (ret)
		return ret;
	return 0;
598 599 600 601 602
}

int btrfs_end_transaction_nolock(struct btrfs_trans_handle *trans,
				 struct btrfs_root *root)
{
603 604 605 606 607 608 609 610 611 612 613 614
	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);
615 616
}

C
Chris Mason 已提交
617 618 619
/*
 * 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
620
 * those extents are sent to disk but does not wait on them
C
Chris Mason 已提交
621
 */
622
int btrfs_write_marked_extents(struct btrfs_root *root,
623
			       struct extent_io_tree *dirty_pages, int mark)
C
Chris Mason 已提交
624
{
625
	int err = 0;
626
	int werr = 0;
J
Josef Bacik 已提交
627
	struct address_space *mapping = root->fs_info->btree_inode->i_mapping;
628
	u64 start = 0;
629
	u64 end;
630

J
Josef Bacik 已提交
631 632 633 634 635 636 637 638 639
	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;
640
	}
641 642 643 644 645 646 647 648 649 650 651 652
	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,
653
			      struct extent_io_tree *dirty_pages, int mark)
654 655 656
{
	int err = 0;
	int werr = 0;
J
Josef Bacik 已提交
657
	struct address_space *mapping = root->fs_info->btree_inode->i_mapping;
658 659
	u64 start = 0;
	u64 end;
660

J
Josef Bacik 已提交
661 662 663 664 665 666 667 668
	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;
669
	}
670 671 672
	if (err)
		werr = err;
	return werr;
C
Chris Mason 已提交
673 674
}

675 676 677 678 679 680
/*
 * 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,
681
				struct extent_io_tree *dirty_pages, int mark)
682 683 684 685
{
	int ret;
	int ret2;

686 687
	ret = btrfs_write_marked_extents(root, dirty_pages, mark);
	ret2 = btrfs_wait_marked_extents(root, dirty_pages, mark);
688 689 690 691 692 693

	if (ret)
		return ret;
	if (ret2)
		return ret2;
	return 0;
694 695
}

696 697 698 699 700 701 702 703 704
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,
705 706
					   &trans->transaction->dirty_pages,
					   EXTENT_DIRTY);
707 708
}

C
Chris Mason 已提交
709 710 711 712 713 714 715 716 717 718
/*
 * 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.
 */
719 720
static int update_cowonly_root(struct btrfs_trans_handle *trans,
			       struct btrfs_root *root)
C
Chris Mason 已提交
721 722
{
	int ret;
723
	u64 old_root_bytenr;
724
	u64 old_root_used;
725
	struct btrfs_root *tree_root = root->fs_info->tree_root;
C
Chris Mason 已提交
726

727
	old_root_used = btrfs_root_used(&root->root_item);
728
	btrfs_write_dirty_block_groups(trans, root);
729

C
Chris Mason 已提交
730
	while (1) {
731
		old_root_bytenr = btrfs_root_bytenr(&root->root_item);
732 733
		if (old_root_bytenr == root->node->start &&
		    old_root_used == btrfs_root_used(&root->root_item))
C
Chris Mason 已提交
734
			break;
735

736
		btrfs_set_root_node(&root->root_item, root->node);
C
Chris Mason 已提交
737
		ret = btrfs_update_root(trans, tree_root,
738 739
					&root->root_key,
					&root->root_item);
740 741
		if (ret)
			return ret;
742

743
		old_root_used = btrfs_root_used(&root->root_item);
744
		ret = btrfs_write_dirty_block_groups(trans, root);
745 746
		if (ret)
			return ret;
747
	}
748 749 750 751

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

752 753 754
	return 0;
}

C
Chris Mason 已提交
755 756
/*
 * update all the cowonly tree roots on disk
757 758 759 760
 *
 * 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
761
 */
762 763
static noinline int commit_cowonly_roots(struct btrfs_trans_handle *trans,
					 struct btrfs_root *root)
764 765 766
{
	struct btrfs_fs_info *fs_info = root->fs_info;
	struct list_head *next;
767
	struct extent_buffer *eb;
768
	int ret;
769

770
	ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1);
771 772
	if (ret)
		return ret;
773

774
	eb = btrfs_lock_root_node(fs_info->tree_root);
775 776
	ret = btrfs_cow_block(trans, fs_info->tree_root, eb, NULL,
			      0, &eb);
777 778
	btrfs_tree_unlock(eb);
	free_extent_buffer(eb);
779

780 781 782
	if (ret)
		return ret;

783
	ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1);
784 785
	if (ret)
		return ret;
786

787 788 789
	ret = btrfs_run_dev_stats(trans, root->fs_info);
	BUG_ON(ret);

C
Chris Mason 已提交
790
	while (!list_empty(&fs_info->dirty_cowonly_roots)) {
791 792 793
		next = fs_info->dirty_cowonly_roots.next;
		list_del_init(next);
		root = list_entry(next, struct btrfs_root, dirty_list);
794

795 796 797
		ret = update_cowonly_root(trans, root);
		if (ret)
			return ret;
C
Chris Mason 已提交
798
	}
799 800 801 802 803

	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
804 805 806
	return 0;
}

C
Chris Mason 已提交
807 808 809 810 811
/*
 * 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
 */
812
int btrfs_add_dead_root(struct btrfs_root *root)
813
{
J
Josef Bacik 已提交
814
	spin_lock(&root->fs_info->trans_lock);
815
	list_add(&root->root_list, &root->fs_info->dead_roots);
J
Josef Bacik 已提交
816
	spin_unlock(&root->fs_info->trans_lock);
817 818 819
	return 0;
}

C
Chris Mason 已提交
820
/*
821
 * update all the cowonly tree roots on disk
C
Chris Mason 已提交
822
 */
823 824
static noinline int commit_fs_roots(struct btrfs_trans_handle *trans,
				    struct btrfs_root *root)
825 826
{
	struct btrfs_root *gang[8];
827
	struct btrfs_fs_info *fs_info = root->fs_info;
828 829
	int i;
	int ret;
830 831
	int err = 0;

J
Josef Bacik 已提交
832
	spin_lock(&fs_info->fs_roots_radix_lock);
C
Chris Mason 已提交
833
	while (1) {
834 835
		ret = radix_tree_gang_lookup_tag(&fs_info->fs_roots_radix,
						 (void **)gang, 0,
836 837 838 839 840 841
						 ARRAY_SIZE(gang),
						 BTRFS_ROOT_TRANS_TAG);
		if (ret == 0)
			break;
		for (i = 0; i < ret; i++) {
			root = gang[i];
842 843 844
			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
845
			spin_unlock(&fs_info->fs_roots_radix_lock);
Y
Yan Zheng 已提交
846

847
			btrfs_free_log(trans, root);
848
			btrfs_update_reloc_root(trans, root);
849
			btrfs_orphan_commit_root(trans, root);
850

851 852
			btrfs_save_ino_cache(root, trans);

853 854 855 856
			/* see comments in should_cow_block() */
			root->force_cow = 0;
			smp_wmb();

857
			if (root->commit_root != root->node) {
858
				mutex_lock(&root->fs_commit_mutex);
J
Josef Bacik 已提交
859
				switch_commit_root(root);
860 861 862
				btrfs_unpin_free_ino(root);
				mutex_unlock(&root->fs_commit_mutex);

863 864 865
				btrfs_set_root_node(&root->root_item,
						    root->node);
			}
866 867

			err = btrfs_update_root(trans, fs_info->tree_root,
868 869
						&root->root_key,
						&root->root_item);
J
Josef Bacik 已提交
870
			spin_lock(&fs_info->fs_roots_radix_lock);
871 872
			if (err)
				break;
873 874
		}
	}
J
Josef Bacik 已提交
875
	spin_unlock(&fs_info->fs_roots_radix_lock);
876
	return err;
877 878
}

C
Chris Mason 已提交
879 880 881 882
/*
 * defrag a given btree.  If cacheonly == 1, this won't read from the disk,
 * otherwise every leaf in the btree is read and defragged.
 */
883 884 885 886
int btrfs_defrag_root(struct btrfs_root *root, int cacheonly)
{
	struct btrfs_fs_info *info = root->fs_info;
	struct btrfs_trans_handle *trans;
887
	int ret;
888
	unsigned long nr;
889

890
	if (xchg(&root->defrag_running, 1))
891
		return 0;
892

893
	while (1) {
894 895 896 897
		trans = btrfs_start_transaction(root, 0);
		if (IS_ERR(trans))
			return PTR_ERR(trans);

898
		ret = btrfs_defrag_leaves(trans, root, cacheonly);
899

900
		nr = trans->blocks_used;
901
		btrfs_end_transaction(trans, root);
902
		btrfs_btree_balance_dirty(info->tree_root, nr);
903 904
		cond_resched();

905
		if (btrfs_fs_closing(root->fs_info) || ret != -EAGAIN)
906 907 908
			break;
	}
	root->defrag_running = 0;
909
	return ret;
910 911
}

C
Chris Mason 已提交
912 913 914 915
/*
 * new snapshots need to be created at a very specific time in the
 * transaction commit.  This does the actual creation
 */
916
static noinline int create_pending_snapshot(struct btrfs_trans_handle *trans,
917 918 919 920
				   struct btrfs_fs_info *fs_info,
				   struct btrfs_pending_snapshot *pending)
{
	struct btrfs_key key;
921
	struct btrfs_root_item *new_root_item;
922 923
	struct btrfs_root *tree_root = fs_info->tree_root;
	struct btrfs_root *root = pending->root;
924
	struct btrfs_root *parent_root;
L
Liu Bo 已提交
925
	struct btrfs_block_rsv *rsv;
926
	struct inode *parent_inode;
927
	struct dentry *parent;
928
	struct dentry *dentry;
929
	struct extent_buffer *tmp;
930
	struct extent_buffer *old;
931
	int ret;
932
	u64 to_reserve = 0;
933
	u64 index = 0;
934
	u64 objectid;
L
Li Zefan 已提交
935
	u64 root_flags;
936

L
Liu Bo 已提交
937 938
	rsv = trans->block_rsv;

939 940
	new_root_item = kmalloc(sizeof(*new_root_item), GFP_NOFS);
	if (!new_root_item) {
941
		ret = pending->error = -ENOMEM;
942 943
		goto fail;
	}
944

945
	ret = btrfs_find_free_objectid(tree_root, &objectid);
946 947
	if (ret) {
		pending->error = ret;
948
		goto fail;
949
	}
950

951
	btrfs_reloc_pre_snapshot(trans, pending, &to_reserve);
952 953

	if (to_reserve > 0) {
954 955
		ret = btrfs_block_rsv_add_noflush(root, &pending->block_rsv,
						  to_reserve);
956 957 958 959 960 961
		if (ret) {
			pending->error = ret;
			goto fail;
		}
	}

962
	key.objectid = objectid;
963 964
	key.offset = (u64)-1;
	key.type = BTRFS_ROOT_ITEM_KEY;
965

966
	trans->block_rsv = &pending->block_rsv;
967

968
	dentry = pending->dentry;
969 970
	parent = dget_parent(dentry);
	parent_inode = parent->d_inode;
971
	parent_root = BTRFS_I(parent_inode)->root;
C
Chris Mason 已提交
972
	record_root_in_trans(trans, parent_root);
973

974 975 976
	/*
	 * insert the directory item
	 */
977
	ret = btrfs_set_inode_index(parent_inode, &index);
978
	BUG_ON(ret); /* -ENOMEM */
979
	ret = btrfs_insert_dir_item(trans, parent_root,
980
				dentry->d_name.name, dentry->d_name.len,
981
				parent_inode, &key,
982
				BTRFS_FT_DIR, index);
983
	if (ret == -EEXIST) {
984 985 986
		pending->error = -EEXIST;
		dput(parent);
		goto fail;
987 988 989
	} else if (ret) {
		goto abort_trans_dput;
	}
990

991 992
	btrfs_i_size_write(parent_inode, parent_inode->i_size +
					 dentry->d_name.len * 2);
993
	ret = btrfs_update_inode(trans, parent_root, parent_inode);
994
	if (ret)
995
		goto abort_trans_dput;
996

997 998 999 1000 1001 1002 1003
	/*
	 * 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);
1004 1005
	if (ret) { /* Transaction aborted */
		dput(parent);
1006
		goto fail;
1007
	}
1008

C
Chris Mason 已提交
1009
	record_root_in_trans(trans, root);
1010 1011
	btrfs_set_root_last_snapshot(&root->root_item, trans->transid);
	memcpy(new_root_item, &root->root_item, sizeof(*new_root_item));
1012
	btrfs_check_and_init_root_item(new_root_item);
1013

L
Li Zefan 已提交
1014 1015 1016 1017 1018 1019 1020
	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);

1021
	old = btrfs_lock_root_node(root);
1022
	ret = btrfs_cow_block(trans, root, old, NULL, 0, &old);
1023 1024 1025 1026 1027
	if (ret) {
		btrfs_tree_unlock(old);
		free_extent_buffer(old);
		goto abort_trans_dput;
	}
1028

1029 1030
	btrfs_set_lock_blocking(old);

1031
	ret = btrfs_copy_root(trans, root, old, &tmp, objectid);
1032
	/* clean up in any case */
1033 1034
	btrfs_tree_unlock(old);
	free_extent_buffer(old);
1035 1036
	if (ret)
		goto abort_trans_dput;
1037

1038 1039 1040 1041
	/* see comments in should_cow_block() */
	root->force_cow = 1;
	smp_wmb();

1042
	btrfs_set_root_node(new_root_item, tmp);
1043 1044 1045
	/* record when the snapshot was created in key.offset */
	key.offset = trans->transid;
	ret = btrfs_insert_root(trans, tree_root, &key, new_root_item);
1046 1047
	btrfs_tree_unlock(tmp);
	free_extent_buffer(tmp);
1048
	if (ret)
1049
		goto abort_trans_dput;
1050

1051 1052 1053 1054
	/*
	 * insert root back/forward references
	 */
	ret = btrfs_add_root_ref(trans, tree_root, objectid,
1055
				 parent_root->root_key.objectid,
L
Li Zefan 已提交
1056
				 btrfs_ino(parent_inode), index,
1057
				 dentry->d_name.name, dentry->d_name.len);
1058
	dput(parent);
1059 1060
	if (ret)
		goto fail;
1061

1062 1063
	key.offset = (u64)-1;
	pending->snap = btrfs_read_fs_root_no_name(root->fs_info, &key);
1064 1065
	if (IS_ERR(pending->snap)) {
		ret = PTR_ERR(pending->snap);
1066
		goto abort_trans;
1067
	}
1068

1069 1070 1071 1072
	ret = btrfs_reloc_post_snapshot(trans, pending);
	if (ret)
		goto abort_trans;
	ret = 0;
1073
fail:
1074
	kfree(new_root_item);
L
Liu Bo 已提交
1075
	trans->block_rsv = rsv;
1076
	btrfs_block_rsv_release(root, &pending->block_rsv, (u64)-1);
1077 1078
	return ret;

1079 1080
abort_trans_dput:
	dput(parent);
1081 1082 1083
abort_trans:
	btrfs_abort_transaction(trans, root, ret);
	goto fail;
1084 1085
}

C
Chris Mason 已提交
1086 1087 1088
/*
 * create all the snapshots we've scheduled for creation
 */
1089 1090
static noinline int create_pending_snapshots(struct btrfs_trans_handle *trans,
					     struct btrfs_fs_info *fs_info)
1091 1092 1093 1094
{
	struct btrfs_pending_snapshot *pending;
	struct list_head *head = &trans->transaction->pending_snapshots;

1095 1096
	list_for_each_entry(pending, head, list)
		create_pending_snapshot(trans, fs_info, pending);
1097 1098 1099
	return 0;
}

1100 1101 1102 1103 1104
static void update_super_roots(struct btrfs_root *root)
{
	struct btrfs_root_item *root_item;
	struct btrfs_super_block *super;

1105
	super = root->fs_info->super_copy;
1106 1107 1108 1109 1110 1111 1112 1113 1114 1115

	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;
1116
	if (btrfs_test_opt(root, SPACE_CACHE))
1117
		super->cache_generation = root_item->generation;
1118 1119
}

1120 1121 1122
int btrfs_transaction_in_commit(struct btrfs_fs_info *info)
{
	int ret = 0;
J
Josef Bacik 已提交
1123
	spin_lock(&info->trans_lock);
1124 1125
	if (info->running_transaction)
		ret = info->running_transaction->in_commit;
J
Josef Bacik 已提交
1126
	spin_unlock(&info->trans_lock);
1127 1128 1129
	return ret;
}

1130 1131 1132
int btrfs_transaction_blocked(struct btrfs_fs_info *info)
{
	int ret = 0;
J
Josef Bacik 已提交
1133
	spin_lock(&info->trans_lock);
1134 1135
	if (info->running_transaction)
		ret = info->running_transaction->blocked;
J
Josef Bacik 已提交
1136
	spin_unlock(&info->trans_lock);
1137 1138 1139
	return ret;
}

S
Sage Weil 已提交
1140 1141 1142 1143 1144 1145 1146
/*
 * 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
1147
	wait_event(root->fs_info->transaction_blocked_wait, trans->in_commit);
S
Sage Weil 已提交
1148 1149 1150 1151 1152 1153 1154 1155 1156
}

/*
 * 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
1157 1158
	wait_event(root->fs_info->transaction_wait,
		   trans->commit_done || (trans->in_commit && !trans->blocked));
S
Sage Weil 已提交
1159 1160 1161 1162 1163 1164 1165 1166 1167 1168 1169 1170 1171 1172 1173 1174 1175 1176 1177 1178 1179 1180 1181 1182 1183 1184 1185 1186 1187
}

/*
 * 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
1188 1189
	if (!ac)
		return -ENOMEM;
S
Sage Weil 已提交
1190 1191 1192

	INIT_DELAYED_WORK(&ac->work, do_async_commit);
	ac->root = root;
1193
	ac->newtrans = btrfs_join_transaction(root);
1194 1195 1196 1197 1198
	if (IS_ERR(ac->newtrans)) {
		int err = PTR_ERR(ac->newtrans);
		kfree(ac);
		return err;
	}
S
Sage Weil 已提交
1199 1200 1201

	/* take transaction reference */
	cur_trans = trans->transaction;
1202
	atomic_inc(&cur_trans->use_count);
S
Sage Weil 已提交
1203 1204 1205 1206 1207 1208 1209 1210 1211 1212

	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);

1213 1214 1215 1216
	if (current->journal_info == trans)
		current->journal_info = NULL;

	put_transaction(cur_trans);
S
Sage Weil 已提交
1217 1218 1219
	return 0;
}

1220 1221

static void cleanup_transaction(struct btrfs_trans_handle *trans,
1222
				struct btrfs_root *root, int err)
1223 1224 1225 1226 1227
{
	struct btrfs_transaction *cur_trans = trans->transaction;

	WARN_ON(trans->use_count > 1);

1228 1229
	btrfs_abort_transaction(trans, root, err);

1230 1231
	spin_lock(&root->fs_info->trans_lock);
	list_del_init(&cur_trans->list);
1232 1233 1234 1235
	if (cur_trans == root->fs_info->running_transaction) {
		root->fs_info->running_transaction = NULL;
		root->fs_info->trans_no_join = 0;
	}
1236 1237 1238 1239 1240 1241 1242 1243 1244 1245 1246 1247 1248 1249 1250 1251 1252
	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
1253 1254 1255 1256 1257 1258 1259
/*
 * 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
1260 1261 1262
int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
			     struct btrfs_root *root)
{
1263
	unsigned long joined = 0;
1264
	struct btrfs_transaction *cur_trans = trans->transaction;
C
Chris Mason 已提交
1265
	struct btrfs_transaction *prev_trans = NULL;
C
Chris Mason 已提交
1266
	DEFINE_WAIT(wait);
1267
	int ret = -EIO;
1268 1269
	int should_grow = 0;
	unsigned long now = get_seconds();
1270
	int flush_on_commit = btrfs_test_opt(root, FLUSHONCOMMIT);
C
Chris Mason 已提交
1271

1272 1273
	btrfs_run_ordered_operations(root, 0);

1274
	btrfs_trans_release_metadata(trans, root);
1275 1276
	trans->block_rsv = NULL;

1277 1278 1279
	if (cur_trans->aborted)
		goto cleanup_transaction;

1280 1281 1282 1283
	/* 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);
1284 1285
	if (ret)
		goto cleanup_transaction;
1286

1287
	cur_trans = trans->transaction;
1288

1289 1290 1291 1292
	/*
	 * set the flushing flag so procs in this transaction have to
	 * start sending their work down.
	 */
1293
	cur_trans->delayed_refs.flushing = 1;
1294

1295
	ret = btrfs_run_delayed_refs(trans, root, 0);
1296 1297
	if (ret)
		goto cleanup_transaction;
1298

J
Josef Bacik 已提交
1299
	spin_lock(&cur_trans->commit_lock);
1300
	if (cur_trans->in_commit) {
J
Josef Bacik 已提交
1301
		spin_unlock(&cur_trans->commit_lock);
1302
		atomic_inc(&cur_trans->use_count);
1303
		ret = btrfs_end_transaction(trans, root);
C
Chris Mason 已提交
1304

1305
		wait_for_commit(root, cur_trans);
1306

C
Chris Mason 已提交
1307
		put_transaction(cur_trans);
1308

1309
		return ret;
C
Chris Mason 已提交
1310
	}
1311

C
Chris Mason 已提交
1312
	trans->transaction->in_commit = 1;
1313
	trans->transaction->blocked = 1;
J
Josef Bacik 已提交
1314
	spin_unlock(&cur_trans->commit_lock);
S
Sage Weil 已提交
1315 1316
	wake_up(&root->fs_info->transaction_blocked_wait);

J
Josef Bacik 已提交
1317
	spin_lock(&root->fs_info->trans_lock);
C
Chris Mason 已提交
1318 1319 1320 1321
	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) {
1322
			atomic_inc(&prev_trans->use_count);
J
Josef Bacik 已提交
1323
			spin_unlock(&root->fs_info->trans_lock);
C
Chris Mason 已提交
1324 1325 1326

			wait_for_commit(root, prev_trans);

1327
			put_transaction(prev_trans);
J
Josef Bacik 已提交
1328 1329
		} else {
			spin_unlock(&root->fs_info->trans_lock);
C
Chris Mason 已提交
1330
		}
J
Josef Bacik 已提交
1331 1332
	} else {
		spin_unlock(&root->fs_info->trans_lock);
C
Chris Mason 已提交
1333
	}
1334

1335 1336 1337
	if (now < cur_trans->start_time || now - cur_trans->start_time < 1)
		should_grow = 1;

1338
	do {
1339
		int snap_pending = 0;
J
Josef Bacik 已提交
1340

1341
		joined = cur_trans->num_joined;
1342 1343 1344
		if (!list_empty(&trans->transaction->pending_snapshots))
			snap_pending = 1;

C
Chris Mason 已提交
1345
		WARN_ON(cur_trans != trans->transaction);
1346

1347
		if (flush_on_commit || snap_pending) {
Y
Yan, Zheng 已提交
1348
			btrfs_start_delalloc_inodes(root, 1);
1349
			btrfs_wait_ordered_extents(root, 0, 1);
1350 1351
		}

1352
		ret = btrfs_run_delayed_items(trans, root);
1353 1354
		if (ret)
			goto cleanup_transaction;
1355

1356 1357 1358 1359 1360 1361 1362 1363 1364
		/*
		 * 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);

1365 1366 1367
		prepare_to_wait(&cur_trans->writer_wait, &wait,
				TASK_UNINTERRUPTIBLE);

1368
		if (atomic_read(&cur_trans->num_writers) > 1)
1369 1370 1371
			schedule_timeout(MAX_SCHEDULE_TIMEOUT);
		else if (should_grow)
			schedule_timeout(1);
1372 1373

		finish_wait(&cur_trans->writer_wait, &wait);
1374
	} while (atomic_read(&cur_trans->num_writers) > 1 ||
1375
		 (should_grow && cur_trans->num_joined != joined));
1376

1377 1378 1379 1380 1381 1382 1383 1384 1385 1386 1387
	/*
	 * 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
1388 1389 1390 1391 1392 1393 1394
	/*
	 * 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);

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

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

1407
	ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1);
1408 1409 1410 1411
	if (ret) {
		mutex_unlock(&root->fs_info->reloc_mutex);
		goto cleanup_transaction;
	}
1412

1413 1414 1415 1416 1417 1418
	/*
	 * 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
1419
	WARN_ON(cur_trans != trans->transaction);
C
Chris Mason 已提交
1420

A
Arne Jansen 已提交
1421
	btrfs_scrub_pause(root);
1422 1423 1424 1425 1426 1427 1428 1429 1430 1431 1432 1433 1434 1435 1436
	/* 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);

1437
	ret = commit_fs_roots(trans, root);
1438 1439
	if (ret) {
		mutex_unlock(&root->fs_info->tree_log_mutex);
1440
		mutex_unlock(&root->fs_info->reloc_mutex);
1441 1442
		goto cleanup_transaction;
	}
1443

1444
	/* commit_fs_roots gets rid of all the tree log roots, it is now
1445 1446 1447 1448
	 * safe to free the root of tree log roots
	 */
	btrfs_free_log_root_tree(trans, root->fs_info);

1449
	ret = commit_cowonly_roots(trans, root);
1450 1451
	if (ret) {
		mutex_unlock(&root->fs_info->tree_log_mutex);
1452
		mutex_unlock(&root->fs_info->reloc_mutex);
1453 1454
		goto cleanup_transaction;
	}
1455

1456 1457
	btrfs_prepare_extent_commit(trans, root);

C
Chris Mason 已提交
1458
	cur_trans = root->fs_info->running_transaction;
1459 1460 1461

	btrfs_set_root_node(&root->fs_info->tree_root->root_item,
			    root->fs_info->tree_root->node);
J
Josef Bacik 已提交
1462
	switch_commit_root(root->fs_info->tree_root);
1463 1464 1465

	btrfs_set_root_node(&root->fs_info->chunk_root->root_item,
			    root->fs_info->chunk_root->node);
J
Josef Bacik 已提交
1466
	switch_commit_root(root->fs_info->chunk_root);
1467 1468

	update_super_roots(root);
1469 1470

	if (!root->fs_info->log_root_recovering) {
1471 1472
		btrfs_set_super_log_root(root->fs_info->super_copy, 0);
		btrfs_set_super_log_root_level(root->fs_info->super_copy, 0);
1473 1474
	}

1475 1476
	memcpy(root->fs_info->super_for_commit, root->fs_info->super_copy,
	       sizeof(*root->fs_info->super_copy));
C
Chris Mason 已提交
1477

1478
	trans->transaction->blocked = 0;
J
Josef Bacik 已提交
1479 1480 1481 1482
	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
1483
	mutex_unlock(&root->fs_info->reloc_mutex);
1484

1485
	wake_up(&root->fs_info->transaction_wait);
1486

C
Chris Mason 已提交
1487
	ret = btrfs_write_and_wait_transaction(trans, root);
1488 1489 1490 1491 1492 1493 1494 1495 1496 1497 1498 1499
	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;
	}
1500

1501 1502 1503 1504 1505 1506
	/*
	 * the super is written, we can safely allow the tree-loggers
	 * to go about their business
	 */
	mutex_unlock(&root->fs_info->tree_log_mutex);

1507
	btrfs_finish_extent_commit(trans, root);
1508

C
Chris Mason 已提交
1509
	cur_trans->commit_done = 1;
1510

1511
	root->fs_info->last_trans_committed = cur_trans->transid;
J
Josef Bacik 已提交
1512

C
Chris Mason 已提交
1513
	wake_up(&cur_trans->commit_wait);
1514

J
Josef Bacik 已提交
1515
	spin_lock(&root->fs_info->trans_lock);
1516
	list_del_init(&cur_trans->list);
J
Josef Bacik 已提交
1517 1518
	spin_unlock(&root->fs_info->trans_lock);

C
Chris Mason 已提交
1519
	put_transaction(cur_trans);
C
Chris Mason 已提交
1520
	put_transaction(cur_trans);
1521

1522 1523
	trace_btrfs_transaction_commit(root);

A
Arne Jansen 已提交
1524 1525
	btrfs_scrub_continue(root);

J
Josef Bacik 已提交
1526 1527 1528
	if (current->journal_info == trans)
		current->journal_info = NULL;

C
Chris Mason 已提交
1529
	kmem_cache_free(btrfs_trans_handle_cachep, trans);
Y
Yan, Zheng 已提交
1530 1531 1532 1533

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

C
Chris Mason 已提交
1534
	return ret;
1535 1536 1537 1538 1539 1540

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;
1541
	cleanup_transaction(trans, root, ret);
1542 1543

	return ret;
C
Chris Mason 已提交
1544 1545
}

C
Chris Mason 已提交
1546 1547 1548
/*
 * interface function to delete all the snapshots we have scheduled for deletion
 */
1549 1550
int btrfs_clean_old_snapshots(struct btrfs_root *root)
{
1551 1552 1553
	LIST_HEAD(list);
	struct btrfs_fs_info *fs_info = root->fs_info;

J
Josef Bacik 已提交
1554
	spin_lock(&fs_info->trans_lock);
1555
	list_splice_init(&fs_info->dead_roots, &list);
J
Josef Bacik 已提交
1556
	spin_unlock(&fs_info->trans_lock);
1557

1558
	while (!list_empty(&list)) {
1559 1560
		int ret;

1561
		root = list_entry(list.next, struct btrfs_root, root_list);
1562 1563
		list_del(&root->root_list);

1564 1565
		btrfs_kill_all_delayed_nodes(root);

1566 1567
		if (btrfs_header_backref_rev(root->node) <
		    BTRFS_MIXED_BACKREF_REV)
1568
			ret = btrfs_drop_snapshot(root, NULL, 0, 0);
1569
		else
1570 1571
			ret =btrfs_drop_snapshot(root, NULL, 1, 0);
		BUG_ON(ret < 0);
1572 1573 1574
	}
	return 0;
}