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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: 0 on success, or one of the following negative error codes on
50 * failure:
51 * * %-EIO - I/O error (including metadata corruption).
52 * * %-ENOENT - The block specified with @pbn does not exist.
53 * * %-ENOMEM - Insufficient memory available.
54 */
55int nilfs_gccache_submit_read_data(struct inode *inode, sector_t blkoff,
56 sector_t pbn, __u64 vbn,
57 struct buffer_head **out_bh)
58{
59 struct buffer_head *bh;
60 int err;
61
62 bh = nilfs_grab_buffer(inode, inode->i_mapping, blkoff, 0);
63 if (unlikely(!bh))
64 return -ENOMEM;
65
66 if (buffer_uptodate(bh))
67 goto out;
68
69 if (pbn == 0) {
70 struct the_nilfs *nilfs = inode->i_sb->s_fs_info;
71
72 err = nilfs_dat_translate(nilfs->ns_dat, vbn, &pbn);
73 if (unlikely(err)) /* -EIO, -ENOMEM, -ENOENT */
74 goto failed;
75 }
76
77 lock_buffer(bh);
78 if (buffer_uptodate(bh)) {
79 unlock_buffer(bh);
80 goto out;
81 }
82
83 if (!buffer_mapped(bh))
84 set_buffer_mapped(bh);
85 bh->b_blocknr = pbn;
86 bh_submit(bh, REQ_OP_READ, bh_end_read);
87 if (vbn)
88 bh->b_blocknr = vbn;
89 out:
90 err = 0;
91 *out_bh = bh;
92
93 failed:
94 folio_unlock(bh->b_folio);
95 folio_put(bh->b_folio);
96 if (unlikely(err))
97 brelse(bh);
98 return err;
99}
100
101/*
102 * nilfs_gccache_submit_read_node() - add node buffer and submit read request
103 * @inode - gc inode
104 * @pbn - physical block number for the block
105 * @vbn - virtual block number for the block
106 * @out_bh - indirect pointer to a buffer_head struct to receive the results
107 *
108 * Description: nilfs_gccache_submit_read_node() registers the node buffer
109 * specified by @vbn to the GC pagecache. @pbn can be supplied by the
110 * caller to avoid translation of the disk block address.
111 *
112 * Return: 0 on success, or one of the following negative error codes on
113 * failure:
114 * * %-EIO - I/O error (including metadata corruption).
115 * * %-ENOENT - Invalid virtual block address.
116 * * %-ENOMEM - Insufficient memory available.
117 */
118int nilfs_gccache_submit_read_node(struct inode *inode, sector_t pbn,
119 __u64 vbn, struct buffer_head **out_bh)
120{
121 struct inode *btnc_inode = NILFS_I(inode)->i_assoc_inode;
122 int ret;
123
124 ret = nilfs_btnode_submit_block(btnc_inode->i_mapping, vbn ? : pbn, pbn,
125 REQ_OP_READ, out_bh, &pbn);
126 if (ret == -EEXIST) /* internal code (cache hit) */
127 ret = 0;
128 return ret;
129}
130
131int nilfs_gccache_wait_and_mark_dirty(struct buffer_head *bh)
132{
133 wait_on_buffer(bh);
134 if (!buffer_uptodate(bh)) {
135 struct inode *inode = bh->b_folio->mapping->host;
136
137 nilfs_err(inode->i_sb,
138 "I/O error reading %s block for GC (ino=%llu, vblocknr=%llu)",
139 buffer_nilfs_node(bh) ? "node" : "data",
140 inode->i_ino, (unsigned long long)bh->b_blocknr);
141 return -EIO;
142 }
143 if (buffer_dirty(bh))
144 return -EEXIST;
145
146 if (buffer_nilfs_node(bh) && nilfs_btree_broken_node_block(bh)) {
147 clear_buffer_uptodate(bh);
148 return -EIO;
149 }
150 mark_buffer_dirty(bh);
151 return 0;
152}
153
154int nilfs_init_gcinode(struct inode *inode)
155{
156 struct nilfs_inode_info *ii = NILFS_I(inode);
157
158 inode->i_mode = S_IFREG;
159 mapping_set_gfp_mask(inode->i_mapping, GFP_NOFS);
160 inode->i_mapping->a_ops = &nilfs_buffer_cache_aops;
161
162 ii->i_flags = 0;
163 nilfs_bmap_init_gc(ii->i_bmap);
164
165 return nilfs_attach_btree_node_cache(inode);
166}
167
168/**
169 * nilfs_remove_all_gcinodes() - remove all unprocessed gc inodes
170 * @nilfs: NILFS filesystem instance
171 */
172void nilfs_remove_all_gcinodes(struct the_nilfs *nilfs)
173{
174 struct list_head *head = &nilfs->ns_gc_inodes;
175 struct nilfs_inode_info *ii;
176
177 while (!list_empty(head)) {
178 ii = list_first_entry(head, struct nilfs_inode_info, i_dirty);
179 list_del_init(&ii->i_dirty);
180 truncate_inode_pages(&ii->vfs_inode.i_data, 0);
181 nilfs_btnode_cache_clear(ii->i_assoc_inode->i_mapping);
182 iput(&ii->vfs_inode);
183 }
184}