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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
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
Arjan van de Ven4b6f5d22006-03-28 01:56:42 -080020const struct file_operations bfs_file_operations = {
Linus Torvalds1da177e2005-04-16 15:20:36 -070021 .llseek = generic_file_llseek,
Badari Pulavarty543ade12006-09-30 23:28:48 -070022 .read = do_sync_read,
23 .aio_read = generic_file_aio_read,
24 .write = do_sync_write,
25 .aio_write = generic_file_aio_write,
Linus Torvalds1da177e2005-04-16 15:20:36 -070026 .mmap = generic_file_mmap,
27 .sendfile = generic_file_sendfile,
28};
29
30static int bfs_move_block(unsigned long from, unsigned long to, struct super_block *sb)
31{
32 struct buffer_head *bh, *new;
33
34 bh = sb_bread(sb, from);
35 if (!bh)
36 return -EIO;
37 new = sb_getblk(sb, to);
38 memcpy(new->b_data, bh->b_data, bh->b_size);
39 mark_buffer_dirty(new);
40 bforget(bh);
41 brelse(new);
42 return 0;
43}
44
Andrew Stribblehillfac92be2005-09-09 13:02:04 -070045static int bfs_move_blocks(struct super_block *sb, unsigned long start,
46 unsigned long end, unsigned long where)
Linus Torvalds1da177e2005-04-16 15:20:36 -070047{
48 unsigned long i;
49
50 dprintf("%08lx-%08lx->%08lx\n", start, end, where);
51 for (i = start; i <= end; i++)
52 if(bfs_move_block(i, where + i, sb)) {
53 dprintf("failed to move block %08lx -> %08lx\n", i, where + i);
54 return -EIO;
55 }
56 return 0;
57}
58
59static int bfs_get_block(struct inode * inode, sector_t block,
60 struct buffer_head * bh_result, int create)
61{
Andrew Stribblehillfac92be2005-09-09 13:02:04 -070062 unsigned long phys;
Linus Torvalds1da177e2005-04-16 15:20:36 -070063 int err;
64 struct super_block *sb = inode->i_sb;
65 struct bfs_sb_info *info = BFS_SB(sb);
66 struct bfs_inode_info *bi = BFS_I(inode);
67 struct buffer_head *sbh = info->si_sbh;
68
Andrew Stribblehillfac92be2005-09-09 13:02:04 -070069 if (block > info->si_blocks)
Linus Torvalds1da177e2005-04-16 15:20:36 -070070 return -EIO;
71
72 phys = bi->i_sblock + block;
73 if (!create) {
74 if (phys <= bi->i_eblock) {
Andrew Stribblehillfac92be2005-09-09 13:02:04 -070075 dprintf("c=%d, b=%08lx, phys=%09lx (granted)\n",
76 create, (unsigned long)block, phys);
Linus Torvalds1da177e2005-04-16 15:20:36 -070077 map_bh(bh_result, sb, phys);
78 }
79 return 0;
80 }
81
82 /* if the file is not empty and the requested block is within the range
83 of blocks allocated for this file, we can grant it */
84 if (inode->i_size && phys <= bi->i_eblock) {
85 dprintf("c=%d, b=%08lx, phys=%08lx (interim block granted)\n",
Andrew Stribblehillfac92be2005-09-09 13:02:04 -070086 create, (unsigned long)block, phys);
Linus Torvalds1da177e2005-04-16 15:20:36 -070087 map_bh(bh_result, sb, phys);
88 return 0;
89 }
90
91 /* the rest has to be protected against itself */
92 lock_kernel();
93
Andrew Stribblehillfac92be2005-09-09 13:02:04 -070094 /* if the last data block for this file is the last allocated
95 block, we can extend the file trivially, without moving it
96 anywhere */
Linus Torvalds1da177e2005-04-16 15:20:36 -070097 if (bi->i_eblock == info->si_lf_eblk) {
98 dprintf("c=%d, b=%08lx, phys=%08lx (simple extension)\n",
Andrew Stribblehillfac92be2005-09-09 13:02:04 -070099 create, (unsigned long)block, phys);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700100 map_bh(bh_result, sb, phys);
101 info->si_freeb -= phys - bi->i_eblock;
102 info->si_lf_eblk = bi->i_eblock = phys;
103 mark_inode_dirty(inode);
104 mark_buffer_dirty(sbh);
105 err = 0;
106 goto out;
107 }
108
109 /* Ok, we have to move this entire file to the next free block */
110 phys = info->si_lf_eblk + 1;
111 if (bi->i_sblock) { /* if data starts on block 0 then there is no data */
112 err = bfs_move_blocks(inode->i_sb, bi->i_sblock,
113 bi->i_eblock, phys);
114 if (err) {
115 dprintf("failed to move ino=%08lx -> fs corruption\n", inode->i_ino);
116 goto out;
117 }
118 } else
119 err = 0;
120
Andrew Stribblehillfac92be2005-09-09 13:02:04 -0700121 dprintf("c=%d, b=%08lx, phys=%08lx (moved)\n",
122 create, (unsigned long)block, phys);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700123 bi->i_sblock = phys;
124 phys += block;
125 info->si_lf_eblk = bi->i_eblock = phys;
126
127 /* this assumes nothing can write the inode back while we are here
128 * and thus update inode->i_blocks! (XXX)*/
129 info->si_freeb -= bi->i_eblock - bi->i_sblock + 1 - inode->i_blocks;
130 mark_inode_dirty(inode);
131 mark_buffer_dirty(sbh);
132 map_bh(bh_result, sb, phys);
133out:
134 unlock_kernel();
135 return err;
136}
137
138static int bfs_writepage(struct page *page, struct writeback_control *wbc)
139{
140 return block_write_full_page(page, bfs_get_block, wbc);
141}
142
143static int bfs_readpage(struct file *file, struct page *page)
144{
145 return block_read_full_page(page, bfs_get_block);
146}
147
148static int bfs_prepare_write(struct file *file, struct page *page, unsigned from, unsigned to)
149{
150 return block_prepare_write(page, from, to, bfs_get_block);
151}
152
153static sector_t bfs_bmap(struct address_space *mapping, sector_t block)
154{
155 return generic_block_bmap(mapping, block, bfs_get_block);
156}
157
Christoph Hellwigf5e54d62006-06-28 04:26:44 -0700158const struct address_space_operations bfs_aops = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700159 .readpage = bfs_readpage,
160 .writepage = bfs_writepage,
161 .sync_page = block_sync_page,
162 .prepare_write = bfs_prepare_write,
163 .commit_write = generic_commit_write,
164 .bmap = bfs_bmap,
165};
166
Arjan van de Ven754661f2007-02-12 00:55:38 -0800167const struct inode_operations bfs_file_inops;