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