forked from mirrors/linux
		
	Extent alloctions are still protected by a large alloc_mutex. Objectid allocations are covered by a objectid mutex Other btree operations are protected by a lock on individual btree nodes Signed-off-by: Chris Mason <chris.mason@oracle.com>
		
			
				
	
	
		
			140 lines
		
	
	
	
		
			3.4 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			140 lines
		
	
	
	
		
			3.4 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
/*
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 * Copyright (C) 2007 Oracle.  All rights reserved.
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 *
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 * This program is free software; you can redistribute it and/or
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 * modify it under the terms of the GNU General Public
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 * License v2 as published by the Free Software Foundation.
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 *
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 * This program is distributed in the hope that it will be useful,
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 * but WITHOUT ANY WARRANTY; without even the implied warranty of
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 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
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 * General Public License for more details.
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 *
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 * You should have received a copy of the GNU General Public
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 * License along with this program; if not, write to the
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 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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 * Boston, MA 021110-1307, USA.
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 */
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#include "ctree.h"
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#include "disk-io.h"
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#include "transaction.h"
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int btrfs_find_highest_inode(struct btrfs_root *root, u64 *objectid)
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{
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	struct btrfs_path *path;
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	int ret;
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	struct extent_buffer *l;
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	struct btrfs_key search_key;
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	struct btrfs_key found_key;
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	int slot;
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	path = btrfs_alloc_path();
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	BUG_ON(!path);
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	search_key.objectid = (u64)-1;
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	search_key.offset = (u64)-1;
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	ret = btrfs_search_slot(NULL, root, &search_key, path, 0, 0);
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	if (ret < 0)
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		goto error;
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	BUG_ON(ret == 0);
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	if (path->slots[0] > 0) {
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		slot = path->slots[0] - 1;
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		l = path->nodes[0];
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		btrfs_item_key_to_cpu(l, &found_key, slot);
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		*objectid = found_key.objectid;
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	} else {
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		*objectid = BTRFS_FIRST_FREE_OBJECTID;
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	}
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	ret = 0;
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error:
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	btrfs_free_path(path);
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	return ret;
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}
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/*
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 * walks the btree of allocated inodes and find a hole.
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 */
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int btrfs_find_free_objectid(struct btrfs_trans_handle *trans,
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			     struct btrfs_root *root,
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			     u64 dirid, u64 *objectid)
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{
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	struct btrfs_path *path;
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	struct btrfs_key key;
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	int ret;
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	int slot = 0;
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	u64 last_ino = 0;
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	int start_found;
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	struct extent_buffer *l;
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	struct btrfs_key search_key;
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	u64 search_start = dirid;
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	mutex_lock(&root->objectid_mutex);
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	if (root->last_inode_alloc) {
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		*objectid = ++root->last_inode_alloc;
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		mutex_unlock(&root->objectid_mutex);
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		return 0;
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	}
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	path = btrfs_alloc_path();
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	BUG_ON(!path);
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	search_start = root->last_inode_alloc;
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	search_start = max(search_start, BTRFS_FIRST_FREE_OBJECTID);
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	search_key.objectid = search_start;
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	search_key.offset = 0;
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	btrfs_init_path(path);
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	start_found = 0;
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	ret = btrfs_search_slot(trans, root, &search_key, path, 0, 0);
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	if (ret < 0)
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		goto error;
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	if (path->slots[0] > 0)
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		path->slots[0]--;
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	while (1) {
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		l = path->nodes[0];
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		slot = path->slots[0];
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		if (slot >= btrfs_header_nritems(l)) {
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			ret = btrfs_next_leaf(root, path);
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			if (ret == 0)
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				continue;
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			if (ret < 0)
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				goto error;
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			if (!start_found) {
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				*objectid = search_start;
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				start_found = 1;
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				goto found;
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			}
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			*objectid = last_ino > search_start ?
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				last_ino : search_start;
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			goto found;
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		}
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		btrfs_item_key_to_cpu(l, &key, slot);
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		if (key.objectid >= search_start) {
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			if (start_found) {
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				if (last_ino < search_start)
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					last_ino = search_start;
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				if (key.objectid > last_ino) {
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					*objectid = last_ino;
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					goto found;
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				}
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			}
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		}
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		start_found = 1;
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		last_ino = key.objectid + 1;
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		path->slots[0]++;
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	}
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	// FIXME -ENOSPC
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found:
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	root->last_inode_alloc = *objectid;
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	btrfs_release_path(root, path);
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	btrfs_free_path(path);
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	BUG_ON(*objectid < search_start);
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	mutex_unlock(&root->objectid_mutex);
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	return 0;
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error:
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	btrfs_release_path(root, path);
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	btrfs_free_path(path);
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	mutex_unlock(&root->objectid_mutex);
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	return ret;
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}
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