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  */
nilfs_gccache_submit_read_data(struct inode * inode,sector_t blkoff,sector_t pbn,__u64 vbn,struct buffer_head ** out_bh)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 			brelse(bh);
78 			goto failed;
79 		}
80 	}
81 
82 	lock_buffer(bh);
83 	if (buffer_uptodate(bh)) {
84 		unlock_buffer(bh);
85 		goto out;
86 	}
87 
88 	if (!buffer_mapped(bh)) {
89 		bh->b_bdev = inode->i_sb->s_bdev;
90 		set_buffer_mapped(bh);
91 	}
92 	bh->b_blocknr = pbn;
93 	bh->b_end_io = end_buffer_read_sync;
94 	get_bh(bh);
95 	submit_bh(REQ_OP_READ, 0, bh);
96 	if (vbn)
97 		bh->b_blocknr = vbn;
98  out:
99 	err = 0;
100 	*out_bh = bh;
101 
102  failed:
103 	unlock_page(bh->b_page);
104 	put_page(bh->b_page);
105 	return err;
106 }
107 
108 /*
109  * nilfs_gccache_submit_read_node() - add node buffer and submit read request
110  * @inode - gc inode
111  * @pbn - physical block number for the block
112  * @vbn - virtual block number for the block
113  * @out_bh - indirect pointer to a buffer_head struct to receive the results
114  *
115  * Description: nilfs_gccache_submit_read_node() registers the node buffer
116  * specified by @vbn to the GC pagecache.  @pbn can be supplied by the
117  * caller to avoid translation of the disk block address.
118  *
119  * Return Value: On success, 0 is returned. On Error, one of the following
120  * negative error code is returned.
121  *
122  * %-EIO - I/O error.
123  *
124  * %-ENOMEM - Insufficient amount of memory available.
125  */
nilfs_gccache_submit_read_node(struct inode * inode,sector_t pbn,__u64 vbn,struct buffer_head ** out_bh)126 int nilfs_gccache_submit_read_node(struct inode *inode, sector_t pbn,
127 				   __u64 vbn, struct buffer_head **out_bh)
128 {
129 	int ret;
130 
131 	ret = nilfs_btnode_submit_block(&NILFS_I(inode)->i_btnode_cache,
132 					vbn ? : pbn, pbn, REQ_OP_READ, 0,
133 					out_bh, &pbn);
134 	if (ret == -EEXIST) /* internal code (cache hit) */
135 		ret = 0;
136 	return ret;
137 }
138 
nilfs_gccache_wait_and_mark_dirty(struct buffer_head * bh)139 int nilfs_gccache_wait_and_mark_dirty(struct buffer_head *bh)
140 {
141 	wait_on_buffer(bh);
142 	if (!buffer_uptodate(bh)) {
143 		struct inode *inode = bh->b_page->mapping->host;
144 
145 		nilfs_err(inode->i_sb,
146 			  "I/O error reading %s block for GC (ino=%lu, vblocknr=%llu)",
147 			  buffer_nilfs_node(bh) ? "node" : "data",
148 			  inode->i_ino, (unsigned long long)bh->b_blocknr);
149 		return -EIO;
150 	}
151 	if (buffer_dirty(bh))
152 		return -EEXIST;
153 
154 	if (buffer_nilfs_node(bh) && nilfs_btree_broken_node_block(bh)) {
155 		clear_buffer_uptodate(bh);
156 		return -EIO;
157 	}
158 	mark_buffer_dirty(bh);
159 	return 0;
160 }
161 
nilfs_init_gcinode(struct inode * inode)162 int nilfs_init_gcinode(struct inode *inode)
163 {
164 	struct nilfs_inode_info *ii = NILFS_I(inode);
165 
166 	inode->i_mode = S_IFREG;
167 	mapping_set_gfp_mask(inode->i_mapping, GFP_NOFS);
168 	inode->i_mapping->a_ops = &empty_aops;
169 
170 	ii->i_flags = 0;
171 	nilfs_bmap_init_gc(ii->i_bmap);
172 
173 	return 0;
174 }
175 
176 /**
177  * nilfs_remove_all_gcinodes() - remove all unprocessed gc inodes
178  */
nilfs_remove_all_gcinodes(struct the_nilfs * nilfs)179 void nilfs_remove_all_gcinodes(struct the_nilfs *nilfs)
180 {
181 	struct list_head *head = &nilfs->ns_gc_inodes;
182 	struct nilfs_inode_info *ii;
183 
184 	while (!list_empty(head)) {
185 		ii = list_first_entry(head, struct nilfs_inode_info, i_dirty);
186 		list_del_init(&ii->i_dirty);
187 		truncate_inode_pages(&ii->vfs_inode.i_data, 0);
188 		nilfs_btnode_cache_clear(&ii->i_btnode_cache);
189 		iput(&ii->vfs_inode);
190 	}
191 }
192