Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | /* |
2 | * fs/bfs/file.c | |
3 | * BFS file operations. | |
4 | * Copyright (C) 1999,2000 Tigran Aivazian <tigran@veritas.com> | |
f433dc56 DV |
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 | * | |
1da177e4 LT |
10 | */ |
11 | ||
12 | #include <linux/fs.h> | |
13 | #include <linux/buffer_head.h> | |
1da177e4 LT |
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 | ||
4b6f5d20 | 24 | const struct file_operations bfs_file_operations = { |
1da177e4 | 25 | .llseek = generic_file_llseek, |
aad4f8bb | 26 | .read_iter = generic_file_read_iter, |
8174202b | 27 | .write_iter = generic_file_write_iter, |
1da177e4 | 28 | .mmap = generic_file_mmap, |
5ffc4ef4 | 29 | .splice_read = generic_file_splice_read, |
1da177e4 LT |
30 | }; |
31 | ||
f433dc56 DV |
32 | static int bfs_move_block(unsigned long from, unsigned long to, |
33 | struct super_block *sb) | |
1da177e4 LT |
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 | ||
fac92bec | 48 | static int bfs_move_blocks(struct super_block *sb, unsigned long start, |
f433dc56 | 49 | unsigned long end, unsigned long where) |
1da177e4 LT |
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)) { | |
f433dc56 DV |
56 | dprintf("failed to move block %08lx -> %08lx\n", i, |
57 | where + i); | |
1da177e4 LT |
58 | return -EIO; |
59 | } | |
60 | return 0; | |
61 | } | |
62 | ||
f433dc56 DV |
63 | static int bfs_get_block(struct inode *inode, sector_t block, |
64 | struct buffer_head *bh_result, int create) | |
1da177e4 | 65 | { |
fac92bec | 66 | unsigned long phys; |
1da177e4 LT |
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); | |
1da177e4 | 71 | |
1da177e4 LT |
72 | phys = bi->i_sblock + block; |
73 | if (!create) { | |
74 | if (phys <= bi->i_eblock) { | |
fac92bec AS |
75 | dprintf("c=%d, b=%08lx, phys=%09lx (granted)\n", |
76 | create, (unsigned long)block, phys); | |
1da177e4 LT |
77 | map_bh(bh_result, sb, phys); |
78 | } | |
79 | return 0; | |
80 | } | |
81 | ||
f433dc56 DV |
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)) { | |
1da177e4 | 87 | dprintf("c=%d, b=%08lx, phys=%08lx (interim block granted)\n", |
fac92bec | 88 | create, (unsigned long)block, phys); |
1da177e4 LT |
89 | map_bh(bh_result, sb, phys); |
90 | return 0; | |
91 | } | |
92 | ||
f433dc56 DV |
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. */ | |
3f165e4c | 98 | mutex_lock(&info->bfs_lock); |
1da177e4 | 99 | |
f433dc56 DV |
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 | */ | |
1da177e4 LT |
105 | if (bi->i_eblock == info->si_lf_eblk) { |
106 | dprintf("c=%d, b=%08lx, phys=%08lx (simple extension)\n", | |
fac92bec | 107 | create, (unsigned long)block, phys); |
1da177e4 LT |
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); | |
1da177e4 LT |
112 | err = 0; |
113 | goto out; | |
114 | } | |
115 | ||
f433dc56 | 116 | /* Ok, we have to move this entire file to the next free block. */ |
1da177e4 | 117 | phys = info->si_lf_eblk + 1; |
f433dc56 DV |
118 | if (phys + block >= info->si_blocks) { |
119 | err = -ENOSPC; | |
120 | goto out; | |
121 | } | |
122 | ||
123 | if (bi->i_sblock) { | |
1da177e4 | 124 | err = bfs_move_blocks(inode->i_sb, bi->i_sblock, |
f433dc56 | 125 | bi->i_eblock, phys); |
1da177e4 | 126 | if (err) { |
f433dc56 DV |
127 | dprintf("failed to move ino=%08lx -> fs corruption\n", |
128 | inode->i_ino); | |
1da177e4 LT |
129 | goto out; |
130 | } | |
131 | } else | |
132 | err = 0; | |
133 | ||
fac92bec AS |
134 | dprintf("c=%d, b=%08lx, phys=%08lx (moved)\n", |
135 | create, (unsigned long)block, phys); | |
1da177e4 LT |
136 | bi->i_sblock = phys; |
137 | phys += block; | |
138 | info->si_lf_eblk = bi->i_eblock = phys; | |
139 | ||
f433dc56 DV |
140 | /* |
141 | * This assumes nothing can write the inode back while we are here | |
142 | * and thus update inode->i_blocks! (XXX) | |
143 | */ | |
1da177e4 LT |
144 | info->si_freeb -= bi->i_eblock - bi->i_sblock + 1 - inode->i_blocks; |
145 | mark_inode_dirty(inode); | |
1da177e4 LT |
146 | map_bh(bh_result, sb, phys); |
147 | out: | |
3f165e4c | 148 | mutex_unlock(&info->bfs_lock); |
1da177e4 LT |
149 | return err; |
150 | } | |
151 | ||
152 | static int bfs_writepage(struct page *page, struct writeback_control *wbc) | |
153 | { | |
154 | return block_write_full_page(page, bfs_get_block, wbc); | |
155 | } | |
156 | ||
157 | static int bfs_readpage(struct file *file, struct page *page) | |
158 | { | |
159 | return block_read_full_page(page, bfs_get_block); | |
160 | } | |
161 | ||
41ddaeeb MS |
162 | static 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) | |
7caef267 | 167 | truncate_pagecache(inode, inode->i_size); |
41ddaeeb MS |
168 | } |
169 | ||
eedcbba5 NP |
170 | static 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) | |
1da177e4 | 173 | { |
155130a4 CH |
174 | int ret; |
175 | ||
176 | ret = block_write_begin(mapping, pos, len, flags, pagep, | |
177 | bfs_get_block); | |
41ddaeeb MS |
178 | if (unlikely(ret)) |
179 | bfs_write_failed(mapping, pos + len); | |
155130a4 CH |
180 | |
181 | return ret; | |
1da177e4 LT |
182 | } |
183 | ||
184 | static sector_t bfs_bmap(struct address_space *mapping, sector_t block) | |
185 | { | |
186 | return generic_block_bmap(mapping, block, bfs_get_block); | |
187 | } | |
188 | ||
f5e54d6e | 189 | const struct address_space_operations bfs_aops = { |
1da177e4 LT |
190 | .readpage = bfs_readpage, |
191 | .writepage = bfs_writepage, | |
eedcbba5 NP |
192 | .write_begin = bfs_write_begin, |
193 | .write_end = generic_write_end, | |
1da177e4 LT |
194 | .bmap = bfs_bmap, |
195 | }; | |
196 | ||
754661f1 | 197 | const struct inode_operations bfs_file_inops; |