nilfs2: B-tree node cache
This adds routines for B-tree node buffers. Signed-off-by: Seiji Kihara <kihara.seiji@lab.ntt.co.jp> Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Ryusuke Konishi
Linus Torvalds
Родитель
36a580eb48
Коммит
a60be987d4
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/*
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* btnode.c - NILFS B-tree node cache
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*
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* Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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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
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* GNU 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 License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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*
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* This file was originally written by Seiji Kihara <kihara@osrg.net>
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* and fully revised by Ryusuke Konishi <ryusuke@osrg.net> for
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* stabilization and simplification.
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*
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*/
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#include <linux/types.h>
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#include <linux/buffer_head.h>
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#include <linux/mm.h>
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#include <linux/backing-dev.h>
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#include "nilfs.h"
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#include "mdt.h"
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#include "dat.h"
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#include "page.h"
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#include "btnode.h"
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void nilfs_btnode_cache_init_once(struct address_space *btnc)
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{
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INIT_RADIX_TREE(&btnc->page_tree, GFP_ATOMIC);
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spin_lock_init(&btnc->tree_lock);
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INIT_LIST_HEAD(&btnc->private_list);
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spin_lock_init(&btnc->private_lock);
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spin_lock_init(&btnc->i_mmap_lock);
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INIT_RAW_PRIO_TREE_ROOT(&btnc->i_mmap);
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INIT_LIST_HEAD(&btnc->i_mmap_nonlinear);
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}
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static struct address_space_operations def_btnode_aops;
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void nilfs_btnode_cache_init(struct address_space *btnc)
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{
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btnc->host = NULL; /* can safely set to host inode ? */
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btnc->flags = 0;
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mapping_set_gfp_mask(btnc, GFP_NOFS);
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btnc->assoc_mapping = NULL;
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btnc->backing_dev_info = &default_backing_dev_info;
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btnc->a_ops = &def_btnode_aops;
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}
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void nilfs_btnode_cache_clear(struct address_space *btnc)
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{
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invalidate_mapping_pages(btnc, 0, -1);
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truncate_inode_pages(btnc, 0);
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}
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int nilfs_btnode_submit_block(struct address_space *btnc, __u64 blocknr,
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sector_t pblocknr, struct buffer_head **pbh,
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int newblk)
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{
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struct buffer_head *bh;
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struct inode *inode = NILFS_BTNC_I(btnc);
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int err;
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bh = nilfs_grab_buffer(inode, btnc, blocknr, 1 << BH_NILFS_Node);
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if (unlikely(!bh))
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return -ENOMEM;
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err = -EEXIST; /* internal code */
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if (newblk) {
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if (unlikely(buffer_mapped(bh) || buffer_uptodate(bh) ||
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buffer_dirty(bh))) {
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brelse(bh);
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BUG();
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}
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bh->b_bdev = NILFS_I_NILFS(inode)->ns_bdev;
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bh->b_blocknr = blocknr;
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set_buffer_mapped(bh);
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set_buffer_uptodate(bh);
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goto found;
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}
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if (buffer_uptodate(bh) || buffer_dirty(bh))
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goto found;
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if (pblocknr == 0) {
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pblocknr = blocknr;
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if (inode->i_ino != NILFS_DAT_INO) {
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struct inode *dat =
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nilfs_dat_inode(NILFS_I_NILFS(inode));
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/* blocknr is a virtual block number */
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err = nilfs_dat_translate(dat, blocknr, &pblocknr);
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if (unlikely(err)) {
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brelse(bh);
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goto out_locked;
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}
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}
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}
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lock_buffer(bh);
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if (buffer_uptodate(bh)) {
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unlock_buffer(bh);
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err = -EEXIST; /* internal code */
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goto found;
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}
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set_buffer_mapped(bh);
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bh->b_bdev = NILFS_I_NILFS(inode)->ns_bdev;
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bh->b_blocknr = pblocknr; /* set block address for read */
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bh->b_end_io = end_buffer_read_sync;
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get_bh(bh);
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submit_bh(READ, bh);
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bh->b_blocknr = blocknr; /* set back to the given block address */
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err = 0;
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found:
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*pbh = bh;
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out_locked:
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unlock_page(bh->b_page);
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page_cache_release(bh->b_page);
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return err;
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}
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int nilfs_btnode_get(struct address_space *btnc, __u64 blocknr,
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sector_t pblocknr, struct buffer_head **pbh, int newblk)
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{
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struct buffer_head *bh;
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int err;
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err = nilfs_btnode_submit_block(btnc, blocknr, pblocknr, pbh, newblk);
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if (err == -EEXIST) /* internal code (cache hit) */
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return 0;
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if (unlikely(err))
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return err;
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bh = *pbh;
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wait_on_buffer(bh);
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if (!buffer_uptodate(bh)) {
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brelse(bh);
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return -EIO;
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}
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return 0;
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}
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/**
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* nilfs_btnode_delete - delete B-tree node buffer
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* @bh: buffer to be deleted
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*
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* nilfs_btnode_delete() invalidates the specified buffer and delete the page
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* including the buffer if the page gets unbusy.
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*/
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void nilfs_btnode_delete(struct buffer_head *bh)
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{
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struct address_space *mapping;
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struct page *page = bh->b_page;
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pgoff_t index = page_index(page);
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int still_dirty;
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page_cache_get(page);
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lock_page(page);
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wait_on_page_writeback(page);
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nilfs_forget_buffer(bh);
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still_dirty = PageDirty(page);
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mapping = page->mapping;
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unlock_page(page);
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page_cache_release(page);
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if (!still_dirty && mapping)
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invalidate_inode_pages2_range(mapping, index, index);
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}
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/**
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* nilfs_btnode_prepare_change_key
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* prepare to move contents of the block for old key to one of new key.
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* the old buffer will not be removed, but might be reused for new buffer.
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* it might return -ENOMEM because of memory allocation errors,
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* and might return -EIO because of disk read errors.
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*/
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int nilfs_btnode_prepare_change_key(struct address_space *btnc,
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struct nilfs_btnode_chkey_ctxt *ctxt)
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{
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struct buffer_head *obh, *nbh;
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struct inode *inode = NILFS_BTNC_I(btnc);
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__u64 oldkey = ctxt->oldkey, newkey = ctxt->newkey;
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int err;
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if (oldkey == newkey)
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return 0;
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obh = ctxt->bh;
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ctxt->newbh = NULL;
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if (inode->i_blkbits == PAGE_CACHE_SHIFT) {
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lock_page(obh->b_page);
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/*
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* We cannot call radix_tree_preload for the kernels older
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* than 2.6.23, because it is not exported for modules.
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*/
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err = radix_tree_preload(GFP_NOFS & ~__GFP_HIGHMEM);
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if (err)
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goto failed_unlock;
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/* BUG_ON(oldkey != obh->b_page->index); */
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if (unlikely(oldkey != obh->b_page->index))
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NILFS_PAGE_BUG(obh->b_page,
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"invalid oldkey %lld (newkey=%lld)",
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(unsigned long long)oldkey,
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(unsigned long long)newkey);
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retry:
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spin_lock_irq(&btnc->tree_lock);
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err = radix_tree_insert(&btnc->page_tree, newkey, obh->b_page);
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spin_unlock_irq(&btnc->tree_lock);
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/*
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* Note: page->index will not change to newkey until
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* nilfs_btnode_commit_change_key() will be called.
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* To protect the page in intermediate state, the page lock
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* is held.
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*/
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radix_tree_preload_end();
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if (!err)
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return 0;
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else if (err != -EEXIST)
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goto failed_unlock;
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err = invalidate_inode_pages2_range(btnc, newkey, newkey);
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if (!err)
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goto retry;
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/* fallback to copy mode */
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unlock_page(obh->b_page);
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}
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err = nilfs_btnode_get(btnc, newkey, 0, &nbh, 1);
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if (likely(!err)) {
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BUG_ON(nbh == obh);
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ctxt->newbh = nbh;
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}
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return err;
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failed_unlock:
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unlock_page(obh->b_page);
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return err;
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}
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/**
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* nilfs_btnode_commit_change_key
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* commit the change_key operation prepared by prepare_change_key().
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*/
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void nilfs_btnode_commit_change_key(struct address_space *btnc,
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struct nilfs_btnode_chkey_ctxt *ctxt)
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{
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struct buffer_head *obh = ctxt->bh, *nbh = ctxt->newbh;
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__u64 oldkey = ctxt->oldkey, newkey = ctxt->newkey;
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struct page *opage;
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if (oldkey == newkey)
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return;
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if (nbh == NULL) { /* blocksize == pagesize */
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opage = obh->b_page;
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if (unlikely(oldkey != opage->index))
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NILFS_PAGE_BUG(opage,
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"invalid oldkey %lld (newkey=%lld)",
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(unsigned long long)oldkey,
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(unsigned long long)newkey);
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if (!test_set_buffer_dirty(obh) && TestSetPageDirty(opage))
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BUG();
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spin_lock_irq(&btnc->tree_lock);
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radix_tree_delete(&btnc->page_tree, oldkey);
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radix_tree_tag_set(&btnc->page_tree, newkey,
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PAGECACHE_TAG_DIRTY);
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spin_unlock_irq(&btnc->tree_lock);
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opage->index = obh->b_blocknr = newkey;
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unlock_page(opage);
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} else {
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nilfs_copy_buffer(nbh, obh);
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nilfs_btnode_mark_dirty(nbh);
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nbh->b_blocknr = newkey;
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ctxt->bh = nbh;
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nilfs_btnode_delete(obh); /* will decrement bh->b_count */
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}
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}
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/**
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* nilfs_btnode_abort_change_key
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* abort the change_key operation prepared by prepare_change_key().
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*/
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void nilfs_btnode_abort_change_key(struct address_space *btnc,
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struct nilfs_btnode_chkey_ctxt *ctxt)
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{
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struct buffer_head *nbh = ctxt->newbh;
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__u64 oldkey = ctxt->oldkey, newkey = ctxt->newkey;
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if (oldkey == newkey)
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return;
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if (nbh == NULL) { /* blocksize == pagesize */
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spin_lock_irq(&btnc->tree_lock);
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radix_tree_delete(&btnc->page_tree, newkey);
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spin_unlock_irq(&btnc->tree_lock);
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unlock_page(ctxt->bh->b_page);
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} else
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brelse(nbh);
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}
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@ -0,0 +1,58 @@
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/*
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* btnode.h - NILFS B-tree node cache
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*
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* Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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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
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* GNU 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 License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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*
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* Written by Seiji Kihara <kihara@osrg.net>
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* Revised by Ryusuke Konishi <ryusuke@osrg.net>
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*/
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#ifndef _NILFS_BTNODE_H
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#define _NILFS_BTNODE_H
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#include <linux/types.h>
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#include <linux/buffer_head.h>
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#include <linux/fs.h>
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#include <linux/backing-dev.h>
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struct nilfs_btnode_chkey_ctxt {
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__u64 oldkey;
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__u64 newkey;
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struct buffer_head *bh;
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struct buffer_head *newbh;
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};
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void nilfs_btnode_cache_init_once(struct address_space *);
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void nilfs_btnode_cache_init(struct address_space *);
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void nilfs_btnode_cache_clear(struct address_space *);
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int nilfs_btnode_submit_block(struct address_space *, __u64, sector_t,
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struct buffer_head **, int);
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int nilfs_btnode_get(struct address_space *, __u64, sector_t,
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struct buffer_head **, int);
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void nilfs_btnode_delete(struct buffer_head *);
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int nilfs_btnode_prepare_change_key(struct address_space *,
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struct nilfs_btnode_chkey_ctxt *);
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void nilfs_btnode_commit_change_key(struct address_space *,
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struct nilfs_btnode_chkey_ctxt *);
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void nilfs_btnode_abort_change_key(struct address_space *,
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struct nilfs_btnode_chkey_ctxt *);
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#define nilfs_btnode_mark_dirty(bh) nilfs_mark_buffer_dirty(bh)
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#endif /* _NILFS_BTNODE_H */
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