Commit | Line | Data |
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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, |
543ade1f BP |
26 | .read = do_sync_read, |
27 | .aio_read = generic_file_aio_read, | |
28 | .write = do_sync_write, | |
29 | .aio_write = generic_file_aio_write, | |
1da177e4 | 30 | .mmap = generic_file_mmap, |
5ffc4ef4 | 31 | .splice_read = generic_file_splice_read, |
1da177e4 LT |
32 | }; |
33 | ||
f433dc56 DV |
34 | static int bfs_move_block(unsigned long from, unsigned long to, |
35 | struct super_block *sb) | |
1da177e4 LT |
36 | { |
37 | struct buffer_head *bh, *new; | |
38 | ||
39 | bh = sb_bread(sb, from); | |
40 | if (!bh) | |
41 | return -EIO; | |
42 | new = sb_getblk(sb, to); | |
43 | memcpy(new->b_data, bh->b_data, bh->b_size); | |
44 | mark_buffer_dirty(new); | |
45 | bforget(bh); | |
46 | brelse(new); | |
47 | return 0; | |
48 | } | |
49 | ||
fac92bec | 50 | static int bfs_move_blocks(struct super_block *sb, unsigned long start, |
f433dc56 | 51 | unsigned long end, unsigned long where) |
1da177e4 LT |
52 | { |
53 | unsigned long i; | |
54 | ||
55 | dprintf("%08lx-%08lx->%08lx\n", start, end, where); | |
56 | for (i = start; i <= end; i++) | |
57 | if(bfs_move_block(i, where + i, sb)) { | |
f433dc56 DV |
58 | dprintf("failed to move block %08lx -> %08lx\n", i, |
59 | where + i); | |
1da177e4 LT |
60 | return -EIO; |
61 | } | |
62 | return 0; | |
63 | } | |
64 | ||
f433dc56 DV |
65 | static int bfs_get_block(struct inode *inode, sector_t block, |
66 | struct buffer_head *bh_result, int create) | |
1da177e4 | 67 | { |
fac92bec | 68 | unsigned long phys; |
1da177e4 LT |
69 | int err; |
70 | struct super_block *sb = inode->i_sb; | |
71 | struct bfs_sb_info *info = BFS_SB(sb); | |
72 | struct bfs_inode_info *bi = BFS_I(inode); | |
73 | struct buffer_head *sbh = info->si_sbh; | |
74 | ||
1da177e4 LT |
75 | phys = bi->i_sblock + block; |
76 | if (!create) { | |
77 | if (phys <= bi->i_eblock) { | |
fac92bec AS |
78 | dprintf("c=%d, b=%08lx, phys=%09lx (granted)\n", |
79 | create, (unsigned long)block, phys); | |
1da177e4 LT |
80 | map_bh(bh_result, sb, phys); |
81 | } | |
82 | return 0; | |
83 | } | |
84 | ||
f433dc56 DV |
85 | /* |
86 | * If the file is not empty and the requested block is within the | |
87 | * range of blocks allocated for this file, we can grant it. | |
88 | */ | |
89 | if (bi->i_sblock && (phys <= bi->i_eblock)) { | |
1da177e4 | 90 | dprintf("c=%d, b=%08lx, phys=%08lx (interim block granted)\n", |
fac92bec | 91 | create, (unsigned long)block, phys); |
1da177e4 LT |
92 | map_bh(bh_result, sb, phys); |
93 | return 0; | |
94 | } | |
95 | ||
f433dc56 DV |
96 | /* The file will be extended, so let's see if there is enough space. */ |
97 | if (phys >= info->si_blocks) | |
98 | return -ENOSPC; | |
99 | ||
100 | /* The rest has to be protected against itself. */ | |
3f165e4c | 101 | mutex_lock(&info->bfs_lock); |
1da177e4 | 102 | |
f433dc56 DV |
103 | /* |
104 | * If the last data block for this file is the last allocated | |
105 | * block, we can extend the file trivially, without moving it | |
106 | * anywhere. | |
107 | */ | |
1da177e4 LT |
108 | if (bi->i_eblock == info->si_lf_eblk) { |
109 | dprintf("c=%d, b=%08lx, phys=%08lx (simple extension)\n", | |
fac92bec | 110 | create, (unsigned long)block, phys); |
1da177e4 LT |
111 | map_bh(bh_result, sb, phys); |
112 | info->si_freeb -= phys - bi->i_eblock; | |
113 | info->si_lf_eblk = bi->i_eblock = phys; | |
114 | mark_inode_dirty(inode); | |
115 | mark_buffer_dirty(sbh); | |
116 | err = 0; | |
117 | goto out; | |
118 | } | |
119 | ||
f433dc56 | 120 | /* Ok, we have to move this entire file to the next free block. */ |
1da177e4 | 121 | phys = info->si_lf_eblk + 1; |
f433dc56 DV |
122 | if (phys + block >= info->si_blocks) { |
123 | err = -ENOSPC; | |
124 | goto out; | |
125 | } | |
126 | ||
127 | if (bi->i_sblock) { | |
1da177e4 | 128 | err = bfs_move_blocks(inode->i_sb, bi->i_sblock, |
f433dc56 | 129 | bi->i_eblock, phys); |
1da177e4 | 130 | if (err) { |
f433dc56 DV |
131 | dprintf("failed to move ino=%08lx -> fs corruption\n", |
132 | inode->i_ino); | |
1da177e4 LT |
133 | goto out; |
134 | } | |
135 | } else | |
136 | err = 0; | |
137 | ||
fac92bec AS |
138 | dprintf("c=%d, b=%08lx, phys=%08lx (moved)\n", |
139 | create, (unsigned long)block, phys); | |
1da177e4 LT |
140 | bi->i_sblock = phys; |
141 | phys += block; | |
142 | info->si_lf_eblk = bi->i_eblock = phys; | |
143 | ||
f433dc56 DV |
144 | /* |
145 | * This assumes nothing can write the inode back while we are here | |
146 | * and thus update inode->i_blocks! (XXX) | |
147 | */ | |
1da177e4 LT |
148 | info->si_freeb -= bi->i_eblock - bi->i_sblock + 1 - inode->i_blocks; |
149 | mark_inode_dirty(inode); | |
150 | mark_buffer_dirty(sbh); | |
151 | map_bh(bh_result, sb, phys); | |
152 | out: | |
3f165e4c | 153 | mutex_unlock(&info->bfs_lock); |
1da177e4 LT |
154 | return err; |
155 | } | |
156 | ||
157 | static int bfs_writepage(struct page *page, struct writeback_control *wbc) | |
158 | { | |
159 | return block_write_full_page(page, bfs_get_block, wbc); | |
160 | } | |
161 | ||
162 | static int bfs_readpage(struct file *file, struct page *page) | |
163 | { | |
164 | return block_read_full_page(page, bfs_get_block); | |
165 | } | |
166 | ||
eedcbba5 NP |
167 | static int bfs_write_begin(struct file *file, struct address_space *mapping, |
168 | loff_t pos, unsigned len, unsigned flags, | |
169 | struct page **pagep, void **fsdata) | |
1da177e4 | 170 | { |
eedcbba5 NP |
171 | *pagep = NULL; |
172 | return block_write_begin(file, mapping, pos, len, flags, | |
173 | pagep, fsdata, bfs_get_block); | |
1da177e4 LT |
174 | } |
175 | ||
176 | static sector_t bfs_bmap(struct address_space *mapping, sector_t block) | |
177 | { | |
178 | return generic_block_bmap(mapping, block, bfs_get_block); | |
179 | } | |
180 | ||
f5e54d6e | 181 | const struct address_space_operations bfs_aops = { |
1da177e4 LT |
182 | .readpage = bfs_readpage, |
183 | .writepage = bfs_writepage, | |
184 | .sync_page = block_sync_page, | |
eedcbba5 NP |
185 | .write_begin = bfs_write_begin, |
186 | .write_end = generic_write_end, | |
1da177e4 LT |
187 | .bmap = bfs_bmap, |
188 | }; | |
189 | ||
754661f1 | 190 | const struct inode_operations bfs_file_inops; |