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1/*
2 * fs/bfs/file.c
3 * BFS file operations.
4 * Copyright (C) 1999,2000 Tigran Aivazian <tigran@veritas.com>
5 *
6 * Make the file block allocation algorithm understand the size
7 * of the underlying block device.
8 * Copyright (C) 2007 Dmitri Vorobiev <dmitri.vorobiev@gmail.com>
9 *
10 */
11
12#include <linux/fs.h>
13#include <linux/buffer_head.h>
14#include "bfs.h"
15
16#undef DEBUG
17
18#ifdef DEBUG
19#define dprintf(x...) printf(x)
20#else
21#define dprintf(x...)
22#endif
23
24const struct file_operations bfs_file_operations = {
25 .llseek = generic_file_llseek,
26 .read_iter = generic_file_read_iter,
27 .write_iter = generic_file_write_iter,
28 .mmap = generic_file_mmap,
29 .splice_read = generic_file_splice_read,
30};
31
32static int bfs_move_block(unsigned long from, unsigned long to,
33 struct super_block *sb)
34{
35 struct buffer_head *bh, *new;
36
37 bh = sb_bread(sb, from);
38 if (!bh)
39 return -EIO;
40 new = sb_getblk(sb, to);
41 memcpy(new->b_data, bh->b_data, bh->b_size);
42 mark_buffer_dirty(new);
43 bforget(bh);
44 brelse(new);
45 return 0;
46}
47
48static int bfs_move_blocks(struct super_block *sb, unsigned long start,
49 unsigned long end, unsigned long where)
50{
51 unsigned long i;
52
53 dprintf("%08lx-%08lx->%08lx\n", start, end, where);
54 for (i = start; i <= end; i++)
55 if(bfs_move_block(i, where + i, sb)) {
56 dprintf("failed to move block %08lx -> %08lx\n", i,
57 where + i);
58 return -EIO;
59 }
60 return 0;
61}
62
63static int bfs_get_block(struct inode *inode, sector_t block,
64 struct buffer_head *bh_result, int create)
65{
66 unsigned long phys;
67 int err;
68 struct super_block *sb = inode->i_sb;
69 struct bfs_sb_info *info = BFS_SB(sb);
70 struct bfs_inode_info *bi = BFS_I(inode);
71
72 phys = bi->i_sblock + block;
73 if (!create) {
74 if (phys <= bi->i_eblock) {
75 dprintf("c=%d, b=%08lx, phys=%09lx (granted)\n",
76 create, (unsigned long)block, phys);
77 map_bh(bh_result, sb, phys);
78 }
79 return 0;
80 }
81
82 /*
83 * If the file is not empty and the requested block is within the
84 * range of blocks allocated for this file, we can grant it.
85 */
86 if (bi->i_sblock && (phys <= bi->i_eblock)) {
87 dprintf("c=%d, b=%08lx, phys=%08lx (interim block granted)\n",
88 create, (unsigned long)block, phys);
89 map_bh(bh_result, sb, phys);
90 return 0;
91 }
92
93 /* The file will be extended, so let's see if there is enough space. */
94 if (phys >= info->si_blocks)
95 return -ENOSPC;
96
97 /* The rest has to be protected against itself. */
98 mutex_lock(&info->bfs_lock);
99
100 /*
101 * If the last data block for this file is the last allocated
102 * block, we can extend the file trivially, without moving it
103 * anywhere.
104 */
105 if (bi->i_eblock == info->si_lf_eblk) {
106 dprintf("c=%d, b=%08lx, phys=%08lx (simple extension)\n",
107 create, (unsigned long)block, phys);
108 map_bh(bh_result, sb, phys);
109 info->si_freeb -= phys - bi->i_eblock;
110 info->si_lf_eblk = bi->i_eblock = phys;
111 mark_inode_dirty(inode);
112 err = 0;
113 goto out;
114 }
115
116 /* Ok, we have to move this entire file to the next free block. */
117 phys = info->si_lf_eblk + 1;
118 if (phys + block >= info->si_blocks) {
119 err = -ENOSPC;
120 goto out;
121 }
122
123 if (bi->i_sblock) {
124 err = bfs_move_blocks(inode->i_sb, bi->i_sblock,
125 bi->i_eblock, phys);
126 if (err) {
127 dprintf("failed to move ino=%08lx -> fs corruption\n",
128 inode->i_ino);
129 goto out;
130 }
131 } else
132 err = 0;
133
134 dprintf("c=%d, b=%08lx, phys=%08lx (moved)\n",
135 create, (unsigned long)block, phys);
136 bi->i_sblock = phys;
137 phys += block;
138 info->si_lf_eblk = bi->i_eblock = phys;
139
140 /*
141 * This assumes nothing can write the inode back while we are here
142 * and thus update inode->i_blocks! (XXX)
143 */
144 info->si_freeb -= bi->i_eblock - bi->i_sblock + 1 - inode->i_blocks;
145 mark_inode_dirty(inode);
146 map_bh(bh_result, sb, phys);
147out:
148 mutex_unlock(&info->bfs_lock);
149 return err;
150}
151
152static int bfs_writepage(struct page *page, struct writeback_control *wbc)
153{
154 return block_write_full_page(page, bfs_get_block, wbc);
155}
156
157static int bfs_readpage(struct file *file, struct page *page)
158{
159 return block_read_full_page(page, bfs_get_block);
160}
161
162static void bfs_write_failed(struct address_space *mapping, loff_t to)
163{
164 struct inode *inode = mapping->host;
165
166 if (to > inode->i_size)
167 truncate_pagecache(inode, inode->i_size);
168}
169
170static int bfs_write_begin(struct file *file, struct address_space *mapping,
171 loff_t pos, unsigned len, unsigned flags,
172 struct page **pagep, void **fsdata)
173{
174 int ret;
175
176 ret = block_write_begin(mapping, pos, len, flags, pagep,
177 bfs_get_block);
178 if (unlikely(ret))
179 bfs_write_failed(mapping, pos + len);
180
181 return ret;
182}
183
184static sector_t bfs_bmap(struct address_space *mapping, sector_t block)
185{
186 return generic_block_bmap(mapping, block, bfs_get_block);
187}
188
189const struct address_space_operations bfs_aops = {
190 .readpage = bfs_readpage,
191 .writepage = bfs_writepage,
192 .write_begin = bfs_write_begin,
193 .write_end = generic_write_end,
194 .bmap = bfs_bmap,
195};
196
197const struct inode_operations bfs_file_inops;
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * fs/bfs/file.c
4 * BFS file operations.
5 * Copyright (C) 1999-2018 Tigran Aivazian <aivazian.tigran@gmail.com>
6 *
7 * Make the file block allocation algorithm understand the size
8 * of the underlying block device.
9 * Copyright (C) 2007 Dmitri Vorobiev <dmitri.vorobiev@gmail.com>
10 *
11 */
12
13#include <linux/fs.h>
14#include <linux/buffer_head.h>
15#include "bfs.h"
16
17#undef DEBUG
18
19#ifdef DEBUG
20#define dprintf(x...) printf(x)
21#else
22#define dprintf(x...)
23#endif
24
25const struct file_operations bfs_file_operations = {
26 .llseek = generic_file_llseek,
27 .read_iter = generic_file_read_iter,
28 .write_iter = generic_file_write_iter,
29 .mmap = generic_file_mmap,
30 .splice_read = generic_file_splice_read,
31};
32
33static int bfs_move_block(unsigned long from, unsigned long to,
34 struct super_block *sb)
35{
36 struct buffer_head *bh, *new;
37
38 bh = sb_bread(sb, from);
39 if (!bh)
40 return -EIO;
41 new = sb_getblk(sb, to);
42 memcpy(new->b_data, bh->b_data, bh->b_size);
43 mark_buffer_dirty(new);
44 bforget(bh);
45 brelse(new);
46 return 0;
47}
48
49static int bfs_move_blocks(struct super_block *sb, unsigned long start,
50 unsigned long end, unsigned long where)
51{
52 unsigned long i;
53
54 dprintf("%08lx-%08lx->%08lx\n", start, end, where);
55 for (i = start; i <= end; i++)
56 if(bfs_move_block(i, where + i, sb)) {
57 dprintf("failed to move block %08lx -> %08lx\n", i,
58 where + i);
59 return -EIO;
60 }
61 return 0;
62}
63
64static int bfs_get_block(struct inode *inode, sector_t block,
65 struct buffer_head *bh_result, int create)
66{
67 unsigned long phys;
68 int err;
69 struct super_block *sb = inode->i_sb;
70 struct bfs_sb_info *info = BFS_SB(sb);
71 struct bfs_inode_info *bi = BFS_I(inode);
72
73 phys = bi->i_sblock + block;
74 if (!create) {
75 if (phys <= bi->i_eblock) {
76 dprintf("c=%d, b=%08lx, phys=%09lx (granted)\n",
77 create, (unsigned long)block, phys);
78 map_bh(bh_result, sb, phys);
79 }
80 return 0;
81 }
82
83 /*
84 * If the file is not empty and the requested block is within the
85 * range of blocks allocated for this file, we can grant it.
86 */
87 if (bi->i_sblock && (phys <= bi->i_eblock)) {
88 dprintf("c=%d, b=%08lx, phys=%08lx (interim block granted)\n",
89 create, (unsigned long)block, phys);
90 map_bh(bh_result, sb, phys);
91 return 0;
92 }
93
94 /* The file will be extended, so let's see if there is enough space. */
95 if (phys >= info->si_blocks)
96 return -ENOSPC;
97
98 /* The rest has to be protected against itself. */
99 mutex_lock(&info->bfs_lock);
100
101 /*
102 * If the last data block for this file is the last allocated
103 * block, we can extend the file trivially, without moving it
104 * anywhere.
105 */
106 if (bi->i_eblock == info->si_lf_eblk) {
107 dprintf("c=%d, b=%08lx, phys=%08lx (simple extension)\n",
108 create, (unsigned long)block, phys);
109 map_bh(bh_result, sb, phys);
110 info->si_freeb -= phys - bi->i_eblock;
111 info->si_lf_eblk = bi->i_eblock = phys;
112 mark_inode_dirty(inode);
113 err = 0;
114 goto out;
115 }
116
117 /* Ok, we have to move this entire file to the next free block. */
118 phys = info->si_lf_eblk + 1;
119 if (phys + block >= info->si_blocks) {
120 err = -ENOSPC;
121 goto out;
122 }
123
124 if (bi->i_sblock) {
125 err = bfs_move_blocks(inode->i_sb, bi->i_sblock,
126 bi->i_eblock, phys);
127 if (err) {
128 dprintf("failed to move ino=%08lx -> fs corruption\n",
129 inode->i_ino);
130 goto out;
131 }
132 } else
133 err = 0;
134
135 dprintf("c=%d, b=%08lx, phys=%08lx (moved)\n",
136 create, (unsigned long)block, phys);
137 bi->i_sblock = phys;
138 phys += block;
139 info->si_lf_eblk = bi->i_eblock = phys;
140
141 /*
142 * This assumes nothing can write the inode back while we are here
143 * and thus update inode->i_blocks! (XXX)
144 */
145 info->si_freeb -= bi->i_eblock - bi->i_sblock + 1 - inode->i_blocks;
146 mark_inode_dirty(inode);
147 map_bh(bh_result, sb, phys);
148out:
149 mutex_unlock(&info->bfs_lock);
150 return err;
151}
152
153static int bfs_writepage(struct page *page, struct writeback_control *wbc)
154{
155 return block_write_full_page(page, bfs_get_block, wbc);
156}
157
158static int bfs_readpage(struct file *file, struct page *page)
159{
160 return block_read_full_page(page, bfs_get_block);
161}
162
163static void bfs_write_failed(struct address_space *mapping, loff_t to)
164{
165 struct inode *inode = mapping->host;
166
167 if (to > inode->i_size)
168 truncate_pagecache(inode, inode->i_size);
169}
170
171static int bfs_write_begin(struct file *file, struct address_space *mapping,
172 loff_t pos, unsigned len, unsigned flags,
173 struct page **pagep, void **fsdata)
174{
175 int ret;
176
177 ret = block_write_begin(mapping, pos, len, flags, pagep,
178 bfs_get_block);
179 if (unlikely(ret))
180 bfs_write_failed(mapping, pos + len);
181
182 return ret;
183}
184
185static sector_t bfs_bmap(struct address_space *mapping, sector_t block)
186{
187 return generic_block_bmap(mapping, block, bfs_get_block);
188}
189
190const struct address_space_operations bfs_aops = {
191 .readpage = bfs_readpage,
192 .writepage = bfs_writepage,
193 .write_begin = bfs_write_begin,
194 .write_end = generic_write_end,
195 .bmap = bfs_bmap,
196};
197
198const struct inode_operations bfs_file_inops;