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 };
  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 }