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