fs/nilfs2/gcinode.c

   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                 return -EIO;
 153         if (buffer_dirty(bh))
 154                 return -EEXIST;
 155
 156         if (buffer_nilfs_node(bh) && nilfs_btree_broken_node_block(bh)) {
 157                 clear_buffer_uptodate(bh);
 158                 return -EIO;
 159         }
 160         mark_buffer_dirty(bh);
 161         return 0;
 162 }
 163
 164 int nilfs_init_gcinode(struct inode *inode)
 165 {
 166         struct nilfs_inode_info *ii = NILFS_I(inode);
 167
 168         inode->i_mode = S_IFREG;
 169         mapping_set_gfp_mask(inode->i_mapping, GFP_NOFS);
 170         inode->i_mapping->a_ops = &empty_aops;
 171
 172         ii->i_flags = 0;
 173         nilfs_bmap_init_gc(ii->i_bmap);
 174
 175         return 0;
 176 }
 177
 178 /**
 179  * nilfs_remove_all_gcinodes() - remove all unprocessed gc inodes
 180  */
 181 void nilfs_remove_all_gcinodes(struct the_nilfs *nilfs)
 182 {
 183         struct list_head *head = &nilfs->ns_gc_inodes;
 184         struct nilfs_inode_info *ii;
 185
 186         while (!list_empty(head)) {
 187                 ii = list_first_entry(head, struct nilfs_inode_info, i_dirty);
 188                 list_del_init(&ii->i_dirty);
 189                 truncate_inode_pages(&ii->vfs_inode.i_data, 0);
 190                 nilfs_btnode_cache_clear(&ii->i_btnode_cache);
 191                 iput(&ii->vfs_inode);
 192         }
 193 }