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 static const struct address_space_operations def_gcinode_aops = { 52 .sync_page = block_sync_page, 53 }; 54 55 /* 56 * nilfs_gccache_submit_read_data() - add data buffer and submit read request 57 * @inode - gc inode 58 * @blkoff - dummy offset treated as the key for the page cache 59 * @pbn - physical block number of the block 60 * @vbn - virtual block number of the block, 0 for non-virtual block 61 * @out_bh - indirect pointer to a buffer_head struct to receive the results 62 * 63 * Description: nilfs_gccache_submit_read_data() registers the data buffer 64 * specified by @pbn to the GC pagecache with the key @blkoff. 65 * This function sets @vbn (@pbn if @vbn is zero) in b_blocknr of the buffer. 66 * 67 * Return Value: On success, 0 is returned. On Error, one of the following 68 * negative error code is returned. 69 * 70 * %-EIO - I/O error. 71 * 72 * %-ENOMEM - Insufficient amount of memory available. 73 * 74 * %-ENOENT - The block specified with @pbn does not exist. 75 */ 76 int nilfs_gccache_submit_read_data(struct inode *inode, sector_t blkoff, 77 sector_t pbn, __u64 vbn, 78 struct buffer_head **out_bh) 79 { 80 struct buffer_head *bh; 81 int err; 82 83 bh = nilfs_grab_buffer(inode, inode->i_mapping, blkoff, 0); 84 if (unlikely(!bh)) 85 return -ENOMEM; 86 87 if (buffer_uptodate(bh)) 88 goto out; 89 90 if (pbn == 0) { 91 struct inode *dat_inode = NILFS_I_NILFS(inode)->ns_dat; 92 /* use original dat, not gc dat. */ 93 err = nilfs_dat_translate(dat_inode, vbn, &pbn); 94 if (unlikely(err)) { /* -EIO, -ENOMEM, -ENOENT */ 95 brelse(bh); 96 goto failed; 97 } 98 } 99 100 lock_buffer(bh); 101 if (buffer_uptodate(bh)) { 102 unlock_buffer(bh); 103 goto out; 104 } 105 106 if (!buffer_mapped(bh)) { 107 bh->b_bdev = NILFS_I_NILFS(inode)->ns_bdev; 108 set_buffer_mapped(bh); 109 } 110 bh->b_blocknr = pbn; 111 bh->b_end_io = end_buffer_read_sync; 112 get_bh(bh); 113 submit_bh(READ, bh); 114 if (vbn) 115 bh->b_blocknr = vbn; 116 out: 117 err = 0; 118 *out_bh = bh; 119 120 failed: 121 unlock_page(bh->b_page); 122 page_cache_release(bh->b_page); 123 return err; 124 } 125 126 /* 127 * nilfs_gccache_submit_read_node() - add node buffer and submit read request 128 * @inode - gc inode 129 * @pbn - physical block number for the block 130 * @vbn - virtual block number for the block 131 * @out_bh - indirect pointer to a buffer_head struct to receive the results 132 * 133 * Description: nilfs_gccache_submit_read_node() registers the node buffer 134 * specified by @vbn to the GC pagecache. @pbn can be supplied by the 135 * caller to avoid translation of the disk block address. 136 * 137 * Return Value: On success, 0 is returned. On Error, one of the following 138 * negative error code is returned. 139 * 140 * %-EIO - I/O error. 141 * 142 * %-ENOMEM - Insufficient amount of memory available. 143 */ 144 int nilfs_gccache_submit_read_node(struct inode *inode, sector_t pbn, 145 __u64 vbn, struct buffer_head **out_bh) 146 { 147 int ret; 148 149 ret = nilfs_btnode_submit_block(&NILFS_I(inode)->i_btnode_cache, 150 vbn ? : pbn, pbn, READ, out_bh, &pbn); 151 if (ret == -EEXIST) /* internal code (cache hit) */ 152 ret = 0; 153 return ret; 154 } 155 156 int nilfs_gccache_wait_and_mark_dirty(struct buffer_head *bh) 157 { 158 wait_on_buffer(bh); 159 if (!buffer_uptodate(bh)) 160 return -EIO; 161 if (buffer_dirty(bh)) 162 return -EEXIST; 163 164 if (buffer_nilfs_node(bh)) { 165 if (nilfs_btree_broken_node_block(bh)) { 166 clear_buffer_uptodate(bh); 167 return -EIO; 168 } 169 nilfs_btnode_mark_dirty(bh); 170 } else { 171 nilfs_mark_buffer_dirty(bh); 172 } 173 return 0; 174 } 175 176 int nilfs_init_gcinode(struct inode *inode) 177 { 178 struct nilfs_inode_info *ii = NILFS_I(inode); 179 180 inode->i_mode = S_IFREG; 181 mapping_set_gfp_mask(inode->i_mapping, GFP_NOFS); 182 inode->i_mapping->a_ops = &def_gcinode_aops; 183 inode->i_mapping->backing_dev_info = inode->i_sb->s_bdi; 184 185 ii->i_flags = 0; 186 nilfs_bmap_init_gc(ii->i_bmap); 187 188 return 0; 189 } 190 191 /** 192 * nilfs_remove_all_gcinodes() - remove all unprocessed gc inodes 193 */ 194 void nilfs_remove_all_gcinodes(struct the_nilfs *nilfs) 195 { 196 struct list_head *head = &nilfs->ns_gc_inodes; 197 struct nilfs_inode_info *ii; 198 199 while (!list_empty(head)) { 200 ii = list_first_entry(head, struct nilfs_inode_info, i_dirty); 201 list_del_init(&ii->i_dirty); 202 iput(&ii->vfs_inode); 203 } 204 } 205