/* * gcinode.c - dummy inodes to buffer blocks for garbage collection * * Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation. * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA * * Written by Seiji Kihara <kihara@osrg.net>, Amagai Yoshiji <amagai@osrg.net>, * and Ryusuke Konishi <ryusuke@osrg.net>. * Revised by Ryusuke Konishi <ryusuke@osrg.net>. * */ /* * This file adds the cache of on-disk blocks to be moved in garbage * collection. The disk blocks are held with dummy inodes (called * gcinodes), and this file provides lookup function of the dummy * inodes and their buffer read function. * * Buffers and pages held by the dummy inodes will be released each * time after they are copied to a new log. Dirty blocks made on the * current generation and the blocks to be moved by GC never overlap * because the dirty blocks make a new generation; they rather must be * written individually. */ #include <linux/buffer_head.h> #include <linux/mpage.h> #include <linux/hash.h> #include <linux/slab.h> #include <linux/swap.h> #include "nilfs.h" #include "btree.h" #include "btnode.h" #include "page.h" #include "mdt.h" #include "dat.h" #include "ifile.h" static const struct address_space_operations def_gcinode_aops = { .sync_page = block_sync_page, }; /* * nilfs_gccache_submit_read_data() - add data buffer and submit read request * @inode - gc inode * @blkoff - dummy offset treated as the key for the page cache * @pbn - physical block number of the block * @vbn - virtual block number of the block, 0 for non-virtual block * @out_bh - indirect pointer to a buffer_head struct to receive the results * * Description: nilfs_gccache_submit_read_data() registers the data buffer * specified by @pbn to the GC pagecache with the key @blkoff. * This function sets @vbn (@pbn if @vbn is zero) in b_blocknr of the buffer. * * Return Value: On success, 0 is returned. On Error, one of the following * negative error code is returned. * * %-EIO - I/O error. * * %-ENOMEM - Insufficient amount of memory available. * * %-ENOENT - The block specified with @pbn does not exist. */ int nilfs_gccache_submit_read_data(struct inode *inode, sector_t blkoff, sector_t pbn, __u64 vbn, struct buffer_head **out_bh) { struct buffer_head *bh; int err; bh = nilfs_grab_buffer(inode, inode->i_mapping, blkoff, 0); if (unlikely(!bh)) return -ENOMEM; if (buffer_uptodate(bh)) goto out; if (pbn == 0) { struct inode *dat_inode = NILFS_I_NILFS(inode)->ns_dat; /* use original dat, not gc dat. */ err = nilfs_dat_translate(dat_inode, vbn, &pbn); if (unlikely(err)) { /* -EIO, -ENOMEM, -ENOENT */ brelse(bh); goto failed; } } lock_buffer(bh); if (buffer_uptodate(bh)) { unlock_buffer(bh); goto out; } if (!buffer_mapped(bh)) { bh->b_bdev = NILFS_I_NILFS(inode)->ns_bdev; set_buffer_mapped(bh); } bh->b_blocknr = pbn; bh->b_end_io = end_buffer_read_sync; get_bh(bh); submit_bh(READ, bh); if (vbn) bh->b_blocknr = vbn; out: err = 0; *out_bh = bh; failed: unlock_page(bh->b_page); page_cache_release(bh->b_page); return err; } /* * nilfs_gccache_submit_read_node() - add node buffer and submit read request * @inode - gc inode * @pbn - physical block number for the block * @vbn - virtual block number for the block * @out_bh - indirect pointer to a buffer_head struct to receive the results * * Description: nilfs_gccache_submit_read_node() registers the node buffer * specified by @vbn to the GC pagecache. @pbn can be supplied by the * caller to avoid translation of the disk block address. * * Return Value: On success, 0 is returned. On Error, one of the following * negative error code is returned. * * %-EIO - I/O error. * * %-ENOMEM - Insufficient amount of memory available. */ int nilfs_gccache_submit_read_node(struct inode *inode, sector_t pbn, __u64 vbn, struct buffer_head **out_bh) { int ret; ret = nilfs_btnode_submit_block(&NILFS_I(inode)->i_btnode_cache, vbn ? : pbn, pbn, READ, out_bh, &pbn); if (ret == -EEXIST) /* internal code (cache hit) */ ret = 0; return ret; } int nilfs_gccache_wait_and_mark_dirty(struct buffer_head *bh) { wait_on_buffer(bh); if (!buffer_uptodate(bh)) return -EIO; if (buffer_dirty(bh)) return -EEXIST; if (buffer_nilfs_node(bh)) { if (nilfs_btree_broken_node_block(bh)) { clear_buffer_uptodate(bh); return -EIO; } nilfs_btnode_mark_dirty(bh); } else { nilfs_mark_buffer_dirty(bh); } return 0; } int nilfs_init_gcinode(struct inode *inode) { struct nilfs_inode_info *ii = NILFS_I(inode); struct the_nilfs *nilfs = NILFS_SB(inode->i_sb)->s_nilfs; inode->i_mode = S_IFREG; mapping_set_gfp_mask(inode->i_mapping, GFP_NOFS); inode->i_mapping->a_ops = &def_gcinode_aops; inode->i_mapping->backing_dev_info = inode->i_sb->s_bdi; ii->i_flags = 0; nilfs_bmap_init_gc(ii->i_bmap); /* * Add the inode to GC inode list. Garbage Collection * is serialized and no two processes manipulate the * list simultaneously. */ igrab(inode); list_add(&NILFS_I(inode)->i_dirty, &nilfs->ns_gc_inodes); return 0; } /** * nilfs_remove_all_gcinodes() - remove all unprocessed gc inodes */ void nilfs_remove_all_gcinodes(struct the_nilfs *nilfs) { struct list_head *head = &nilfs->ns_gc_inodes; struct nilfs_inode_info *ii; while (!list_empty(head)) { ii = list_first_entry(head, struct nilfs_inode_info, i_dirty); list_del_init(&ii->i_dirty); iput(&ii->vfs_inode); } }