forked from Minki/linux
bcc63abbf3
The memory reclaiming issue happens when snapshot exists. In that case, some cache entries may not be used during old snapshot dropping, so they will remain in the cache until umount. The patch adds a field to struct btrfs_leaf_ref to record create time. Besides, the patch makes all dead roots of a given snapshot linked together in order of create time. After a old snapshot was completely dropped, we check the dead root list and remove all cache entries created before the oldest dead root in the list. Signed-off-by: Chris Mason <chris.mason@oracle.com>
59 lines
1.5 KiB
C
59 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 <asm/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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