922a631d50
There is a indirect recursion which can reach the extent reservation:
btrfs_reserve_extent() <--|
|- do_chunk_alloc() |
|- btrfs_alloc_chunk() |
|- btrfs_insert_item() |
|- btrfs_reserve_extent() <--|
Currently, we're using root->ref_cows to determine whether we should do
chunk prealloc to avoid such loop.
But that's still a hidden trap. Instead of solving it using some hidden
tricks, this patch will make chunk/block group allocation exclusive.
Now if do_chunk_alloc() determines to alloc chunk, it will set a flag in
transaction handle so new call of do_chunk_alloc() will refuse to
allocate new chunk until current chunk allocation finishes.
The chunks get over-allocated by 2M so there's enough space in case the
recursive call asks for a different type of blockgroup.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
52 lines
1.6 KiB
C
52 lines
1.6 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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#ifndef __BTRFS_TRANSACTION_H__
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#define __BTRFS_TRANSACTION_H__
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#include "kerncompat.h"
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#include "ctree.h"
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#include "delayed-ref.h"
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struct btrfs_trans_handle {
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struct btrfs_fs_info *fs_info;
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u64 transid;
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u64 alloc_exclude_start;
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u64 alloc_exclude_nr;
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bool reinit_extent_tree;
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unsigned int allocating_chunk:1;
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u64 delayed_ref_updates;
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unsigned long blocks_reserved;
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unsigned long blocks_used;
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struct btrfs_block_group_cache *block_group;
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struct btrfs_delayed_ref_root delayed_refs;
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};
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struct btrfs_trans_handle* btrfs_start_transaction(struct btrfs_root *root,
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int num_blocks);
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int __commit_transaction(struct btrfs_trans_handle *trans,
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struct btrfs_root *root);
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int commit_tree_roots(struct btrfs_trans_handle *trans,
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struct btrfs_fs_info *fs_info);
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int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
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struct btrfs_root *root);
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void btrfs_abort_transaction(struct btrfs_trans_handle *trans, int error);
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#endif
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