forked from Minki/linux
6dddcbeb28
Lockdep has the notion of locking subclasses so that you can identify locks you expect to be taken after other locks of the same class. This changes the per-extent buffer btree locking routines to use a subclass based on the level in the tree. Unfortunately, lockdep can only handle 8 total subclasses, and the btrfs max level is also 8. So when lockdep is on, use a lower max level. Signed-off-by: Chris Mason <chris.mason@oracle.com>
60 lines
1.5 KiB
C
60 lines
1.5 KiB
C
/*
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* Copyright (C) 2008 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 <linux/sched.h>
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#include <linux/gfp.h>
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#include <linux/pagemap.h>
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#include <linux/spinlock.h>
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#include <linux/page-flags.h>
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#include <linux/bug.h>
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#include "ctree.h"
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#include "extent_io.h"
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#include "locking.h"
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int btrfs_tree_lock(struct extent_buffer *eb)
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{
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int i;
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if (mutex_trylock(&eb->mutex))
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return 0;
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for (i = 0; i < 512; i++) {
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cpu_relax();
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if (mutex_trylock(&eb->mutex))
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return 0;
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}
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cpu_relax();
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mutex_lock_nested(&eb->mutex, BTRFS_MAX_LEVEL - btrfs_header_level(eb));
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return 0;
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}
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int btrfs_try_tree_lock(struct extent_buffer *eb)
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{
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return mutex_trylock(&eb->mutex);
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}
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int btrfs_tree_unlock(struct extent_buffer *eb)
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{
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mutex_unlock(&eb->mutex);
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return 0;
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}
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int btrfs_tree_locked(struct extent_buffer *eb)
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{
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return mutex_is_locked(&eb->mutex);
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}
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