fs/nilfs2/gcinode.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * Dummy inodes to buffer blocks for garbage collection
   4  *
   5  * Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
   6  *
   7  * Written by Seiji Kihara, Amagai Yoshiji, and Ryusuke Konishi.
   8  * Revised by Ryusuke Konishi.
   9  *
  10  */
  11 /*
  12  * This file adds the cache of on-disk blocks to be moved in garbage
  13  * collection.  The disk blocks are held with dummy inodes (called
  14  * gcinodes), and this file provides lookup function of the dummy
  15  * inodes and their buffer read function.
  16  *
  17  * Buffers and pages held by the dummy inodes will be released each
  18  * time after they are copied to a new log.  Dirty blocks made on the
  19  * current generation and the blocks to be moved by GC never overlap
  20  * because the dirty blocks make a new generation; they rather must be
  21  * written individually.
  22  */
  23
  24 #include <linux/buffer_head.h>
  25 #include <linux/mpage.h>
  26 #include <linux/hash.h>
  27 #include <linux/slab.h>
  28 #include <linux/swap.h>
  29 #include "nilfs.h"
  30 #include "btree.h"
  31 #include "btnode.h"
  32 #include "page.h"
  33 #include "mdt.h"
  34 #include "dat.h"
  35 #include "ifile.h"
  36
  37 /*
  38  * nilfs_gccache_submit_read_data() - add data buffer and submit read request
  39  * @inode - gc inode
  40  * @blkoff - dummy offset treated as the key for the page cache
  41  * @pbn - physical block number of the block
  42  * @vbn - virtual block number of the block, 0 for non-virtual block
  43  * @out_bh - indirect pointer to a buffer_head struct to receive the results
  44  *
  45  * Description: nilfs_gccache_submit_read_data() registers the data buffer
  46  * specified by @pbn to the GC pagecache with the key @blkoff.
  47  * This function sets @vbn (@pbn if @vbn is zero) in b_blocknr of the buffer.
  48  *
  49  * Return Value: On success, 0 is returned. On Error, one of the following
  50  * negative error code is returned.
  51  *
  52  * %-EIO - I/O error.
  53  *
  54  * %-ENOMEM - Insufficient amount of memory available.
  55  *
  56  * %-ENOENT - The block specified with @pbn does not exist.
  57  */
  58 int nilfs_gccache_submit_read_data(struct inode *inode, sector_t blkoff,
  59                                    sector_t pbn, __u64 vbn,
  60                                    struct buffer_head **out_bh)
  61 {
  62         struct buffer_head *bh;
  63         int err;
  64
  65         bh = nilfs_grab_buffer(inode, inode->i_mapping, blkoff, 0);
  66         if (unlikely(!bh))
  67                 return -ENOMEM;
  68
  69         if (buffer_uptodate(bh))
  70                 goto out;
  71
  72         if (pbn == 0) {
  73                 struct the_nilfs *nilfs = inode->i_sb->s_fs_info;
  74
  75                 err = nilfs_dat_translate(nilfs->ns_dat, vbn, &pbn);
  76                 if (unlikely(err)) /* -EIO, -ENOMEM, -ENOENT */
  77                         goto failed;
  78         }
  79
  80         lock_buffer(bh);
  81         if (buffer_uptodate(bh)) {
  82                 unlock_buffer(bh);
  83                 goto out;
  84         }
  85
  86         if (!buffer_mapped(bh))
  87                 set_buffer_mapped(bh);
  88         bh->b_blocknr = pbn;
  89         bh->b_end_io = end_buffer_read_sync;
  90         get_bh(bh);
  91         submit_bh(REQ_OP_READ, bh);
  92         if (vbn)
  93                 bh->b_blocknr = vbn;
  94  out:
  95         err = 0;
  96         *out_bh = bh;
  97
  98  failed:
  99         folio_unlock(bh->b_folio);
 100         folio_put(bh->b_folio);
 101         if (unlikely(err))
 102                 brelse(bh);
 103         return err;
 104 }
 105
 106 /*
 107  * nilfs_gccache_submit_read_node() - add node buffer and submit read request
 108  * @inode - gc inode
 109  * @pbn - physical block number for the block
 110  * @vbn - virtual block number for the block
 111  * @out_bh - indirect pointer to a buffer_head struct to receive the results
 112  *
 113  * Description: nilfs_gccache_submit_read_node() registers the node buffer
 114  * specified by @vbn to the GC pagecache.  @pbn can be supplied by the
 115  * caller to avoid translation of the disk block address.
 116  *
 117  * Return Value: On success, 0 is returned. On Error, one of the following
 118  * negative error code is returned.
 119  *
 120  * %-EIO - I/O error.
 121  *
 122  * %-ENOMEM - Insufficient amount of memory available.
 123  */
 124 int nilfs_gccache_submit_read_node(struct inode *inode, sector_t pbn,
 125                                    __u64 vbn, struct buffer_head **out_bh)
 126 {
 127         struct inode *btnc_inode = NILFS_I(inode)->i_assoc_inode;
 128         int ret;
 129
 130         ret = nilfs_btnode_submit_block(btnc_inode->i_mapping, vbn ? : pbn, pbn,
 131                                         REQ_OP_READ, out_bh, &pbn);
 132         if (ret == -EEXIST) /* internal code (cache hit) */
 133                 ret = 0;
 134         return ret;
 135 }
 136
 137 int nilfs_gccache_wait_and_mark_dirty(struct buffer_head *bh)
 138 {
 139         wait_on_buffer(bh);
 140         if (!buffer_uptodate(bh)) {
 141                 struct inode *inode = bh->b_folio->mapping->host;
 142
 143                 nilfs_err(inode->i_sb,
 144                           "I/O error reading %s block for GC (ino=%lu, vblocknr=%llu)",
 145                           buffer_nilfs_node(bh) ? "node" : "data",
 146                           inode->i_ino, (unsigned long long)bh->b_blocknr);
 147                 return -EIO;
 148         }
 149         if (buffer_dirty(bh))
 150                 return -EEXIST;
 151
 152         if (buffer_nilfs_node(bh) && nilfs_btree_broken_node_block(bh)) {
 153                 clear_buffer_uptodate(bh);
 154                 return -EIO;
 155         }
 156         mark_buffer_dirty(bh);
 157         return 0;
 158 }
 159
 160 int nilfs_init_gcinode(struct inode *inode)
 161 {
 162         struct nilfs_inode_info *ii = NILFS_I(inode);
 163
 164         inode->i_mode = S_IFREG;
 165         mapping_set_gfp_mask(inode->i_mapping, GFP_NOFS);
 166         inode->i_mapping->a_ops = &empty_aops;
 167
 168         ii->i_flags = 0;
 169         nilfs_bmap_init_gc(ii->i_bmap);
 170
 171         return nilfs_attach_btree_node_cache(inode);
 172 }
 173
 174 /**
 175  * nilfs_remove_all_gcinodes() - remove all unprocessed gc inodes
 176  * @nilfs: NILFS filesystem instance
 177  */
 178 void nilfs_remove_all_gcinodes(struct the_nilfs *nilfs)
 179 {
 180         struct list_head *head = &nilfs->ns_gc_inodes;
 181         struct nilfs_inode_info *ii;
 182
 183         while (!list_empty(head)) {
 184                 ii = list_first_entry(head, struct nilfs_inode_info, i_dirty);
 185                 list_del_init(&ii->i_dirty);
 186                 truncate_inode_pages(&ii->vfs_inode.i_data, 0);
 187                 nilfs_btnode_cache_clear(ii->i_assoc_inode->i_mapping);
 188                 iput(&ii->vfs_inode);
 189         }
 190 }