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* gcinode.c - dummy inodes to buffer blocks for garbage collection
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* Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
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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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* 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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* 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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* Written by Seiji Kihara <kihara@osrg.net>, Amagai Yoshiji <amagai@osrg.net>,
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* and Ryusuke Konishi <ryusuke@osrg.net>.
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* Revised by Ryusuke Konishi <ryusuke@osrg.net>.
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* This file adds the cache of on-disk blocks to be moved in garbage
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* collection. The disk blocks are held with dummy inodes (called
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* gcinodes), and this file provides lookup function of the dummy
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* inodes and their buffer read function.
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* Buffers and pages held by the dummy inodes will be released each
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* time after they are copied to a new log. Dirty blocks made on the
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* current generation and the blocks to be moved by GC never overlap
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* because the dirty blocks make a new generation; they rather must be
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* written individually.
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#include <linux/buffer_head.h>
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#include <linux/mpage.h>
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#include <linux/hash.h>
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#include <linux/slab.h>
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#include <linux/swap.h>
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* nilfs_gccache_submit_read_data() - add data buffer and submit read request
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* @blkoff - dummy offset treated as the key for the page cache
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* @pbn - physical block number of the block
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* @vbn - virtual block number of the block, 0 for non-virtual block
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* @out_bh - indirect pointer to a buffer_head struct to receive the results
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* Description: nilfs_gccache_submit_read_data() registers the data buffer
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* specified by @pbn to the GC pagecache with the key @blkoff.
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* This function sets @vbn (@pbn if @vbn is zero) in b_blocknr of the buffer.
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* Return Value: On success, 0 is returned. On Error, one of the following
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* negative error code is returned.
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* %-ENOMEM - Insufficient amount of memory available.
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* %-ENOENT - The block specified with @pbn does not exist.
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int nilfs_gccache_submit_read_data(struct inode *inode, sector_t blkoff,
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sector_t pbn, __u64 vbn,
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struct buffer_head **out_bh)
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struct buffer_head *bh;
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bh = nilfs_grab_buffer(inode, inode->i_mapping, blkoff, 0);
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if (buffer_uptodate(bh))
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struct the_nilfs *nilfs = inode->i_sb->s_fs_info;
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err = nilfs_dat_translate(nilfs->ns_dat, vbn, &pbn);
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if (unlikely(err)) { /* -EIO, -ENOMEM, -ENOENT */
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if (buffer_uptodate(bh)) {
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if (!buffer_mapped(bh)) {
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bh->b_bdev = inode->i_sb->s_bdev;
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set_buffer_mapped(bh);
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bh->b_end_io = end_buffer_read_sync;
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unlock_page(bh->b_page);
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page_cache_release(bh->b_page);
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* nilfs_gccache_submit_read_node() - add node buffer and submit read request
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* @pbn - physical block number for the block
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* @vbn - virtual block number for the block
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* @out_bh - indirect pointer to a buffer_head struct to receive the results
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* Description: nilfs_gccache_submit_read_node() registers the node buffer
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* specified by @vbn to the GC pagecache. @pbn can be supplied by the
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* caller to avoid translation of the disk block address.
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* Return Value: On success, 0 is returned. On Error, one of the following
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* negative error code is returned.
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* %-ENOMEM - Insufficient amount of memory available.
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int nilfs_gccache_submit_read_node(struct inode *inode, sector_t pbn,
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__u64 vbn, struct buffer_head **out_bh)
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ret = nilfs_btnode_submit_block(&NILFS_I(inode)->i_btnode_cache,
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vbn ? : pbn, pbn, READ, out_bh, &pbn);
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if (ret == -EEXIST) /* internal code (cache hit) */
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int nilfs_gccache_wait_and_mark_dirty(struct buffer_head *bh)
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if (!buffer_uptodate(bh))
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if (buffer_dirty(bh))
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if (buffer_nilfs_node(bh) && nilfs_btree_broken_node_block(bh)) {
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clear_buffer_uptodate(bh);
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mark_buffer_dirty(bh);
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int nilfs_init_gcinode(struct inode *inode)
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struct nilfs_inode_info *ii = NILFS_I(inode);
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inode->i_mode = S_IFREG;
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mapping_set_gfp_mask(inode->i_mapping, GFP_NOFS);
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inode->i_mapping->a_ops = &empty_aops;
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inode->i_mapping->backing_dev_info = inode->i_sb->s_bdi;
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nilfs_bmap_init_gc(ii->i_bmap);
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* nilfs_remove_all_gcinodes() - remove all unprocessed gc inodes
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void nilfs_remove_all_gcinodes(struct the_nilfs *nilfs)
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struct list_head *head = &nilfs->ns_gc_inodes;
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struct nilfs_inode_info *ii;
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while (!list_empty(head)) {
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ii = list_first_entry(head, struct nilfs_inode_info, i_dirty);
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list_del_init(&ii->i_dirty);
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iput(&ii->vfs_inode);