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  * 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 }