| 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 | * Written by Seiji Kihara, Amagai Yoshiji, and Ryusuke Konishi. |
| 17 | * Revised by Ryusuke Konishi. |
| 18 | * |
| 19 | */ |
| 20 | /* |
| 21 | * This file adds the cache of on-disk blocks to be moved in garbage |
| 22 | * collection. The disk blocks are held with dummy inodes (called |
| 23 | * gcinodes), and this file provides lookup function of the dummy |
| 24 | * inodes and their buffer read function. |
| 25 | * |
| 26 | * Buffers and pages held by the dummy inodes will be released each |
| 27 | * time after they are copied to a new log. Dirty blocks made on the |
| 28 | * current generation and the blocks to be moved by GC never overlap |
| 29 | * because the dirty blocks make a new generation; they rather must be |
| 30 | * written individually. |
| 31 | */ |
| 32 | |
| 33 | #include <linux/buffer_head.h> |
| 34 | #include <linux/mpage.h> |
| 35 | #include <linux/hash.h> |
| 36 | #include <linux/slab.h> |
| 37 | #include <linux/swap.h> |
| 38 | #include "nilfs.h" |
| 39 | #include "btree.h" |
| 40 | #include "btnode.h" |
| 41 | #include "page.h" |
| 42 | #include "mdt.h" |
| 43 | #include "dat.h" |
| 44 | #include "ifile.h" |
| 45 | |
| 46 | /* |
| 47 | * nilfs_gccache_submit_read_data() - add data buffer and submit read request |
| 48 | * @inode - gc inode |
| 49 | * @blkoff - dummy offset treated as the key for the page cache |
| 50 | * @pbn - physical block number of the block |
| 51 | * @vbn - virtual block number of the block, 0 for non-virtual block |
| 52 | * @out_bh - indirect pointer to a buffer_head struct to receive the results |
| 53 | * |
| 54 | * Description: nilfs_gccache_submit_read_data() registers the data buffer |
| 55 | * specified by @pbn to the GC pagecache with the key @blkoff. |
| 56 | * This function sets @vbn (@pbn if @vbn is zero) in b_blocknr of the buffer. |
| 57 | * |
| 58 | * Return Value: On success, 0 is returned. On Error, one of the following |
| 59 | * negative error code is returned. |
| 60 | * |
| 61 | * %-EIO - I/O error. |
| 62 | * |
| 63 | * %-ENOMEM - Insufficient amount of memory available. |
| 64 | * |
| 65 | * %-ENOENT - The block specified with @pbn does not exist. |
| 66 | */ |
| 67 | int nilfs_gccache_submit_read_data(struct inode *inode, sector_t blkoff, |
| 68 | sector_t pbn, __u64 vbn, |
| 69 | struct buffer_head **out_bh) |
| 70 | { |
| 71 | struct buffer_head *bh; |
| 72 | int err; |
| 73 | |
| 74 | bh = nilfs_grab_buffer(inode, inode->i_mapping, blkoff, 0); |
| 75 | if (unlikely(!bh)) |
| 76 | return -ENOMEM; |
| 77 | |
| 78 | if (buffer_uptodate(bh)) |
| 79 | goto out; |
| 80 | |
| 81 | if (pbn == 0) { |
| 82 | struct the_nilfs *nilfs = inode->i_sb->s_fs_info; |
| 83 | |
| 84 | err = nilfs_dat_translate(nilfs->ns_dat, vbn, &pbn); |
| 85 | if (unlikely(err)) { /* -EIO, -ENOMEM, -ENOENT */ |
| 86 | brelse(bh); |
| 87 | goto failed; |
| 88 | } |
| 89 | } |
| 90 | |
| 91 | lock_buffer(bh); |
| 92 | if (buffer_uptodate(bh)) { |
| 93 | unlock_buffer(bh); |
| 94 | goto out; |
| 95 | } |
| 96 | |
| 97 | if (!buffer_mapped(bh)) { |
| 98 | bh->b_bdev = inode->i_sb->s_bdev; |
| 99 | set_buffer_mapped(bh); |
| 100 | } |
| 101 | bh->b_blocknr = pbn; |
| 102 | bh->b_end_io = end_buffer_read_sync; |
| 103 | get_bh(bh); |
| 104 | submit_bh(REQ_OP_READ, 0, bh); |
| 105 | if (vbn) |
| 106 | bh->b_blocknr = vbn; |
| 107 | out: |
| 108 | err = 0; |
| 109 | *out_bh = bh; |
| 110 | |
| 111 | failed: |
| 112 | unlock_page(bh->b_page); |
| 113 | put_page(bh->b_page); |
| 114 | return err; |
| 115 | } |
| 116 | |
| 117 | /* |
| 118 | * nilfs_gccache_submit_read_node() - add node buffer and submit read request |
| 119 | * @inode - gc inode |
| 120 | * @pbn - physical block number for the block |
| 121 | * @vbn - virtual block number for the block |
| 122 | * @out_bh - indirect pointer to a buffer_head struct to receive the results |
| 123 | * |
| 124 | * Description: nilfs_gccache_submit_read_node() registers the node buffer |
| 125 | * specified by @vbn to the GC pagecache. @pbn can be supplied by the |
| 126 | * caller to avoid translation of the disk block address. |
| 127 | * |
| 128 | * Return Value: On success, 0 is returned. On Error, one of the following |
| 129 | * negative error code is returned. |
| 130 | * |
| 131 | * %-EIO - I/O error. |
| 132 | * |
| 133 | * %-ENOMEM - Insufficient amount of memory available. |
| 134 | */ |
| 135 | int nilfs_gccache_submit_read_node(struct inode *inode, sector_t pbn, |
| 136 | __u64 vbn, struct buffer_head **out_bh) |
| 137 | { |
| 138 | int ret; |
| 139 | |
| 140 | ret = nilfs_btnode_submit_block(&NILFS_I(inode)->i_btnode_cache, |
| 141 | vbn ? : pbn, pbn, REQ_OP_READ, 0, |
| 142 | out_bh, &pbn); |
| 143 | if (ret == -EEXIST) /* internal code (cache hit) */ |
| 144 | ret = 0; |
| 145 | return ret; |
| 146 | } |
| 147 | |
| 148 | int nilfs_gccache_wait_and_mark_dirty(struct buffer_head *bh) |
| 149 | { |
| 150 | wait_on_buffer(bh); |
| 151 | if (!buffer_uptodate(bh)) { |
| 152 | struct inode *inode = bh->b_page->mapping->host; |
| 153 | |
| 154 | nilfs_msg(inode->i_sb, KERN_ERR, |
| 155 | "I/O error reading %s block for GC (ino=%lu, vblocknr=%llu)", |
| 156 | buffer_nilfs_node(bh) ? "node" : "data", |
| 157 | inode->i_ino, (unsigned long long)bh->b_blocknr); |
| 158 | return -EIO; |
| 159 | } |
| 160 | if (buffer_dirty(bh)) |
| 161 | return -EEXIST; |
| 162 | |
| 163 | if (buffer_nilfs_node(bh) && nilfs_btree_broken_node_block(bh)) { |
| 164 | clear_buffer_uptodate(bh); |
| 165 | return -EIO; |
| 166 | } |
| 167 | mark_buffer_dirty(bh); |
| 168 | return 0; |
| 169 | } |
| 170 | |
| 171 | int nilfs_init_gcinode(struct inode *inode) |
| 172 | { |
| 173 | struct nilfs_inode_info *ii = NILFS_I(inode); |
| 174 | |
| 175 | inode->i_mode = S_IFREG; |
| 176 | mapping_set_gfp_mask(inode->i_mapping, GFP_NOFS); |
| 177 | inode->i_mapping->a_ops = &empty_aops; |
| 178 | |
| 179 | ii->i_flags = 0; |
| 180 | nilfs_bmap_init_gc(ii->i_bmap); |
| 181 | |
| 182 | return 0; |
| 183 | } |
| 184 | |
| 185 | /** |
| 186 | * nilfs_remove_all_gcinodes() - remove all unprocessed gc inodes |
| 187 | */ |
| 188 | void nilfs_remove_all_gcinodes(struct the_nilfs *nilfs) |
| 189 | { |
| 190 | struct list_head *head = &nilfs->ns_gc_inodes; |
| 191 | struct nilfs_inode_info *ii; |
| 192 | |
| 193 | while (!list_empty(head)) { |
| 194 | ii = list_first_entry(head, struct nilfs_inode_info, i_dirty); |
| 195 | list_del_init(&ii->i_dirty); |
| 196 | truncate_inode_pages(&ii->vfs_inode.i_data, 0); |
| 197 | nilfs_btnode_cache_clear(&ii->i_btnode_cache); |
| 198 | iput(&ii->vfs_inode); |
| 199 | } |
| 200 | } |