1 /* 2 * gcinode.c - dummy inodes to buffer blocks for garbage collection 3 * 4 * Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation. 5 * 6 * This program is free software; you can redistribute it and/or modify 7 * it under the terms of the GNU General Public License as published by 8 * the Free Software Foundation; either version 2 of the License, or 9 * (at your option) any later version. 10 * 11 * This program is distributed in the hope that it will be useful, 12 * but WITHOUT ANY WARRANTY; without even the implied warranty of 13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 14 * GNU General Public License for more details. 15 * 16 * You should have received a copy of the GNU General Public License 17 * along with this program; if not, write to the Free Software 18 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA 19 * 20 * Written by Seiji Kihara <kihara@osrg.net>, Amagai Yoshiji <amagai@osrg.net>, 21 * and Ryusuke Konishi <ryusuke@osrg.net>. 22 * Revised by Ryusuke Konishi <ryusuke@osrg.net>. 23 * 24 */ 25 /* 26 * This file adds the cache of on-disk blocks to be moved in garbage 27 * collection. The disk blocks are held with dummy inodes (called 28 * gcinodes), and this file provides lookup function of the dummy 29 * inodes and their buffer read function. 30 * 31 * Buffers and pages held by the dummy inodes will be released each 32 * time after they are copied to a new log. Dirty blocks made on the 33 * current generation and the blocks to be moved by GC never overlap 34 * because the dirty blocks make a new generation; they rather must be 35 * written individually. 36 */ 37 38 #include <linux/buffer_head.h> 39 #include <linux/mpage.h> 40 #include <linux/hash.h> 41 #include <linux/slab.h> 42 #include <linux/swap.h> 43 #include "nilfs.h" 44 #include "btree.h" 45 #include "btnode.h" 46 #include "page.h" 47 #include "mdt.h" 48 #include "dat.h" 49 #include "ifile.h" 50 51 /* 52 * nilfs_gccache_submit_read_data() - add data buffer and submit read request 53 * @inode - gc inode 54 * @blkoff - dummy offset treated as the key for the page cache 55 * @pbn - physical block number of the block 56 * @vbn - virtual block number of the block, 0 for non-virtual block 57 * @out_bh - indirect pointer to a buffer_head struct to receive the results 58 * 59 * Description: nilfs_gccache_submit_read_data() registers the data buffer 60 * specified by @pbn to the GC pagecache with the key @blkoff. 61 * This function sets @vbn (@pbn if @vbn is zero) in b_blocknr of the buffer. 62 * 63 * Return Value: On success, 0 is returned. On Error, one of the following 64 * negative error code is returned. 65 * 66 * %-EIO - I/O error. 67 * 68 * %-ENOMEM - Insufficient amount of memory available. 69 * 70 * %-ENOENT - The block specified with @pbn does not exist. 71 */ 72 int nilfs_gccache_submit_read_data(struct inode *inode, sector_t blkoff, 73 sector_t pbn, __u64 vbn, 74 struct buffer_head **out_bh) 75 { 76 struct buffer_head *bh; 77 int err; 78 79 bh = nilfs_grab_buffer(inode, inode->i_mapping, blkoff, 0); 80 if (unlikely(!bh)) 81 return -ENOMEM; 82 83 if (buffer_uptodate(bh)) 84 goto out; 85 86 if (pbn == 0) { 87 struct the_nilfs *nilfs = inode->i_sb->s_fs_info; 88 89 err = nilfs_dat_translate(nilfs->ns_dat, vbn, &pbn); 90 if (unlikely(err)) { /* -EIO, -ENOMEM, -ENOENT */ 91 brelse(bh); 92 goto failed; 93 } 94 } 95 96 lock_buffer(bh); 97 if (buffer_uptodate(bh)) { 98 unlock_buffer(bh); 99 goto out; 100 } 101 102 if (!buffer_mapped(bh)) { 103 bh->b_bdev = inode->i_sb->s_bdev; 104 set_buffer_mapped(bh); 105 } 106 bh->b_blocknr = pbn; 107 bh->b_end_io = end_buffer_read_sync; 108 get_bh(bh); 109 submit_bh(READ, bh); 110 if (vbn) 111 bh->b_blocknr = vbn; 112 out: 113 err = 0; 114 *out_bh = bh; 115 116 failed: 117 unlock_page(bh->b_page); 118 page_cache_release(bh->b_page); 119 return err; 120 } 121 122 /* 123 * nilfs_gccache_submit_read_node() - add node buffer and submit read request 124 * @inode - gc inode 125 * @pbn - physical block number for the block 126 * @vbn - virtual block number for the block 127 * @out_bh - indirect pointer to a buffer_head struct to receive the results 128 * 129 * Description: nilfs_gccache_submit_read_node() registers the node buffer 130 * specified by @vbn to the GC pagecache. @pbn can be supplied by the 131 * caller to avoid translation of the disk block address. 132 * 133 * Return Value: On success, 0 is returned. On Error, one of the following 134 * negative error code is returned. 135 * 136 * %-EIO - I/O error. 137 * 138 * %-ENOMEM - Insufficient amount of memory available. 139 */ 140 int nilfs_gccache_submit_read_node(struct inode *inode, sector_t pbn, 141 __u64 vbn, struct buffer_head **out_bh) 142 { 143 int ret; 144 145 ret = nilfs_btnode_submit_block(&NILFS_I(inode)->i_btnode_cache, 146 vbn ? : pbn, pbn, READ, out_bh, &pbn); 147 if (ret == -EEXIST) /* internal code (cache hit) */ 148 ret = 0; 149 return ret; 150 } 151 152 int nilfs_gccache_wait_and_mark_dirty(struct buffer_head *bh) 153 { 154 wait_on_buffer(bh); 155 if (!buffer_uptodate(bh)) 156 return -EIO; 157 if (buffer_dirty(bh)) 158 return -EEXIST; 159 160 if (buffer_nilfs_node(bh) && nilfs_btree_broken_node_block(bh)) { 161 clear_buffer_uptodate(bh); 162 return -EIO; 163 } 164 mark_buffer_dirty(bh); 165 return 0; 166 } 167 168 int nilfs_init_gcinode(struct inode *inode) 169 { 170 struct nilfs_inode_info *ii = NILFS_I(inode); 171 172 inode->i_mode = S_IFREG; 173 mapping_set_gfp_mask(inode->i_mapping, GFP_NOFS); 174 inode->i_mapping->a_ops = &empty_aops; 175 inode->i_mapping->backing_dev_info = inode->i_sb->s_bdi; 176 177 ii->i_flags = 0; 178 nilfs_bmap_init_gc(ii->i_bmap); 179 180 return 0; 181 } 182 183 /** 184 * nilfs_remove_all_gcinodes() - remove all unprocessed gc inodes 185 */ 186 void nilfs_remove_all_gcinodes(struct the_nilfs *nilfs) 187 { 188 struct list_head *head = &nilfs->ns_gc_inodes; 189 struct nilfs_inode_info *ii; 190 191 while (!list_empty(head)) { 192 ii = list_first_entry(head, struct nilfs_inode_info, i_dirty); 193 list_del_init(&ii->i_dirty); 194 iput(&ii->vfs_inode); 195 } 196 } 197