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> | |
5 | */ | |
6 | ||
7 | #include <linux/fs.h> | |
8 | #include <linux/buffer_head.h> | |
9 | #include <linux/smp_lock.h> | |
10 | #include "bfs.h" | |
11 | ||
12 | #undef DEBUG | |
13 | ||
14 | #ifdef DEBUG | |
15 | #define dprintf(x...) printf(x) | |
16 | #else | |
17 | #define dprintf(x...) | |
18 | #endif | |
19 | ||
20 | struct file_operations bfs_file_operations = { | |
21 | .llseek = generic_file_llseek, | |
22 | .read = generic_file_read, | |
23 | .write = generic_file_write, | |
24 | .mmap = generic_file_mmap, | |
25 | .sendfile = generic_file_sendfile, | |
26 | }; | |
27 | ||
28 | static int bfs_move_block(unsigned long from, unsigned long to, struct super_block *sb) | |
29 | { | |
30 | struct buffer_head *bh, *new; | |
31 | ||
32 | bh = sb_bread(sb, from); | |
33 | if (!bh) | |
34 | return -EIO; | |
35 | new = sb_getblk(sb, to); | |
36 | memcpy(new->b_data, bh->b_data, bh->b_size); | |
37 | mark_buffer_dirty(new); | |
38 | bforget(bh); | |
39 | brelse(new); | |
40 | return 0; | |
41 | } | |
42 | ||
43 | static int bfs_move_blocks(struct super_block *sb, unsigned long start, unsigned long end, | |
44 | unsigned long where) | |
45 | { | |
46 | unsigned long i; | |
47 | ||
48 | dprintf("%08lx-%08lx->%08lx\n", start, end, where); | |
49 | for (i = start; i <= end; i++) | |
50 | if(bfs_move_block(i, where + i, sb)) { | |
51 | dprintf("failed to move block %08lx -> %08lx\n", i, where + i); | |
52 | return -EIO; | |
53 | } | |
54 | return 0; | |
55 | } | |
56 | ||
57 | static int bfs_get_block(struct inode * inode, sector_t block, | |
58 | struct buffer_head * bh_result, int create) | |
59 | { | |
60 | long phys; | |
61 | int err; | |
62 | struct super_block *sb = inode->i_sb; | |
63 | struct bfs_sb_info *info = BFS_SB(sb); | |
64 | struct bfs_inode_info *bi = BFS_I(inode); | |
65 | struct buffer_head *sbh = info->si_sbh; | |
66 | ||
67 | if (block < 0 || block > info->si_blocks) | |
68 | return -EIO; | |
69 | ||
70 | phys = bi->i_sblock + block; | |
71 | if (!create) { | |
72 | if (phys <= bi->i_eblock) { | |
73 | dprintf("c=%d, b=%08lx, phys=%08lx (granted)\n", create, block, phys); | |
74 | map_bh(bh_result, sb, phys); | |
75 | } | |
76 | return 0; | |
77 | } | |
78 | ||
79 | /* if the file is not empty and the requested block is within the range | |
80 | of blocks allocated for this file, we can grant it */ | |
81 | if (inode->i_size && phys <= bi->i_eblock) { | |
82 | dprintf("c=%d, b=%08lx, phys=%08lx (interim block granted)\n", | |
83 | create, block, phys); | |
84 | map_bh(bh_result, sb, phys); | |
85 | return 0; | |
86 | } | |
87 | ||
88 | /* the rest has to be protected against itself */ | |
89 | lock_kernel(); | |
90 | ||
91 | /* if the last data block for this file is the last allocated block, we can | |
92 | extend the file trivially, without moving it anywhere */ | |
93 | if (bi->i_eblock == info->si_lf_eblk) { | |
94 | dprintf("c=%d, b=%08lx, phys=%08lx (simple extension)\n", | |
95 | create, block, phys); | |
96 | map_bh(bh_result, sb, phys); | |
97 | info->si_freeb -= phys - bi->i_eblock; | |
98 | info->si_lf_eblk = bi->i_eblock = phys; | |
99 | mark_inode_dirty(inode); | |
100 | mark_buffer_dirty(sbh); | |
101 | err = 0; | |
102 | goto out; | |
103 | } | |
104 | ||
105 | /* Ok, we have to move this entire file to the next free block */ | |
106 | phys = info->si_lf_eblk + 1; | |
107 | if (bi->i_sblock) { /* if data starts on block 0 then there is no data */ | |
108 | err = bfs_move_blocks(inode->i_sb, bi->i_sblock, | |
109 | bi->i_eblock, phys); | |
110 | if (err) { | |
111 | dprintf("failed to move ino=%08lx -> fs corruption\n", inode->i_ino); | |
112 | goto out; | |
113 | } | |
114 | } else | |
115 | err = 0; | |
116 | ||
117 | dprintf("c=%d, b=%08lx, phys=%08lx (moved)\n", create, block, phys); | |
118 | bi->i_sblock = phys; | |
119 | phys += block; | |
120 | info->si_lf_eblk = bi->i_eblock = phys; | |
121 | ||
122 | /* this assumes nothing can write the inode back while we are here | |
123 | * and thus update inode->i_blocks! (XXX)*/ | |
124 | info->si_freeb -= bi->i_eblock - bi->i_sblock + 1 - inode->i_blocks; | |
125 | mark_inode_dirty(inode); | |
126 | mark_buffer_dirty(sbh); | |
127 | map_bh(bh_result, sb, phys); | |
128 | out: | |
129 | unlock_kernel(); | |
130 | return err; | |
131 | } | |
132 | ||
133 | static int bfs_writepage(struct page *page, struct writeback_control *wbc) | |
134 | { | |
135 | return block_write_full_page(page, bfs_get_block, wbc); | |
136 | } | |
137 | ||
138 | static int bfs_readpage(struct file *file, struct page *page) | |
139 | { | |
140 | return block_read_full_page(page, bfs_get_block); | |
141 | } | |
142 | ||
143 | static int bfs_prepare_write(struct file *file, struct page *page, unsigned from, unsigned to) | |
144 | { | |
145 | return block_prepare_write(page, from, to, bfs_get_block); | |
146 | } | |
147 | ||
148 | static sector_t bfs_bmap(struct address_space *mapping, sector_t block) | |
149 | { | |
150 | return generic_block_bmap(mapping, block, bfs_get_block); | |
151 | } | |
152 | ||
153 | struct address_space_operations bfs_aops = { | |
154 | .readpage = bfs_readpage, | |
155 | .writepage = bfs_writepage, | |
156 | .sync_page = block_sync_page, | |
157 | .prepare_write = bfs_prepare_write, | |
158 | .commit_write = generic_commit_write, | |
159 | .bmap = bfs_bmap, | |
160 | }; | |
161 | ||
162 | struct inode_operations bfs_file_inops; |