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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>
Dmitri Vorobievf433dc52007-11-14 16:59:47 -08005 *
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 *
Linus Torvalds1da177e2005-04-16 15:20:36 -070010 */
11
12#include <linux/fs.h>
13#include <linux/buffer_head.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070014#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
Arjan van de Ven4b6f5d22006-03-28 01:56:42 -080024const struct file_operations bfs_file_operations = {
Linus Torvalds1da177e2005-04-16 15:20:36 -070025 .llseek = generic_file_llseek,
Badari Pulavarty543ade12006-09-30 23:28:48 -070026 .read = do_sync_read,
27 .aio_read = generic_file_aio_read,
28 .write = do_sync_write,
29 .aio_write = generic_file_aio_write,
Linus Torvalds1da177e2005-04-16 15:20:36 -070030 .mmap = generic_file_mmap,
Jens Axboe5ffc4ef2007-06-01 11:49:19 +020031 .splice_read = generic_file_splice_read,
Linus Torvalds1da177e2005-04-16 15:20:36 -070032};
33
Dmitri Vorobievf433dc52007-11-14 16:59:47 -080034static int bfs_move_block(unsigned long from, unsigned long to,
35 struct super_block *sb)
Linus Torvalds1da177e2005-04-16 15:20:36 -070036{
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
Andrew Stribblehillfac92be2005-09-09 13:02:04 -070050static int bfs_move_blocks(struct super_block *sb, unsigned long start,
Dmitri Vorobievf433dc52007-11-14 16:59:47 -080051 unsigned long end, unsigned long where)
Linus Torvalds1da177e2005-04-16 15:20:36 -070052{
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)) {
Dmitri Vorobievf433dc52007-11-14 16:59:47 -080058 dprintf("failed to move block %08lx -> %08lx\n", i,
59 where + i);
Linus Torvalds1da177e2005-04-16 15:20:36 -070060 return -EIO;
61 }
62 return 0;
63}
64
Dmitri Vorobievf433dc52007-11-14 16:59:47 -080065static int bfs_get_block(struct inode *inode, sector_t block,
66 struct buffer_head *bh_result, int create)
Linus Torvalds1da177e2005-04-16 15:20:36 -070067{
Andrew Stribblehillfac92be2005-09-09 13:02:04 -070068 unsigned long phys;
Linus Torvalds1da177e2005-04-16 15:20:36 -070069 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);
Linus Torvalds1da177e2005-04-16 15:20:36 -070073
Linus Torvalds1da177e2005-04-16 15:20:36 -070074 phys = bi->i_sblock + block;
75 if (!create) {
76 if (phys <= bi->i_eblock) {
Andrew Stribblehillfac92be2005-09-09 13:02:04 -070077 dprintf("c=%d, b=%08lx, phys=%09lx (granted)\n",
78 create, (unsigned long)block, phys);
Linus Torvalds1da177e2005-04-16 15:20:36 -070079 map_bh(bh_result, sb, phys);
80 }
81 return 0;
82 }
83
Dmitri Vorobievf433dc52007-11-14 16:59:47 -080084 /*
85 * If the file is not empty and the requested block is within the
86 * range of blocks allocated for this file, we can grant it.
87 */
88 if (bi->i_sblock && (phys <= bi->i_eblock)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -070089 dprintf("c=%d, b=%08lx, phys=%08lx (interim block granted)\n",
Andrew Stribblehillfac92be2005-09-09 13:02:04 -070090 create, (unsigned long)block, phys);
Linus Torvalds1da177e2005-04-16 15:20:36 -070091 map_bh(bh_result, sb, phys);
92 return 0;
93 }
94
Dmitri Vorobievf433dc52007-11-14 16:59:47 -080095 /* The file will be extended, so let's see if there is enough space. */
96 if (phys >= info->si_blocks)
97 return -ENOSPC;
98
99 /* The rest has to be protected against itself. */
Dmitri Vorobiev3f165e42008-07-25 19:44:54 -0700100 mutex_lock(&info->bfs_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700101
Dmitri Vorobievf433dc52007-11-14 16:59:47 -0800102 /*
103 * If the last data block for this file is the last allocated
104 * block, we can extend the file trivially, without moving it
105 * anywhere.
106 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700107 if (bi->i_eblock == info->si_lf_eblk) {
108 dprintf("c=%d, b=%08lx, phys=%08lx (simple extension)\n",
Andrew Stribblehillfac92be2005-09-09 13:02:04 -0700109 create, (unsigned long)block, phys);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700110 map_bh(bh_result, sb, phys);
111 info->si_freeb -= phys - bi->i_eblock;
112 info->si_lf_eblk = bi->i_eblock = phys;
113 mark_inode_dirty(inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700114 err = 0;
115 goto out;
116 }
117
Dmitri Vorobievf433dc52007-11-14 16:59:47 -0800118 /* Ok, we have to move this entire file to the next free block. */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700119 phys = info->si_lf_eblk + 1;
Dmitri Vorobievf433dc52007-11-14 16:59:47 -0800120 if (phys + block >= info->si_blocks) {
121 err = -ENOSPC;
122 goto out;
123 }
124
125 if (bi->i_sblock) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700126 err = bfs_move_blocks(inode->i_sb, bi->i_sblock,
Dmitri Vorobievf433dc52007-11-14 16:59:47 -0800127 bi->i_eblock, phys);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700128 if (err) {
Dmitri Vorobievf433dc52007-11-14 16:59:47 -0800129 dprintf("failed to move ino=%08lx -> fs corruption\n",
130 inode->i_ino);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700131 goto out;
132 }
133 } else
134 err = 0;
135
Andrew Stribblehillfac92be2005-09-09 13:02:04 -0700136 dprintf("c=%d, b=%08lx, phys=%08lx (moved)\n",
137 create, (unsigned long)block, phys);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700138 bi->i_sblock = phys;
139 phys += block;
140 info->si_lf_eblk = bi->i_eblock = phys;
141
Dmitri Vorobievf433dc52007-11-14 16:59:47 -0800142 /*
143 * This assumes nothing can write the inode back while we are here
144 * and thus update inode->i_blocks! (XXX)
145 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700146 info->si_freeb -= bi->i_eblock - bi->i_sblock + 1 - inode->i_blocks;
147 mark_inode_dirty(inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700148 map_bh(bh_result, sb, phys);
149out:
Dmitri Vorobiev3f165e42008-07-25 19:44:54 -0700150 mutex_unlock(&info->bfs_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700151 return err;
152}
153
154static int bfs_writepage(struct page *page, struct writeback_control *wbc)
155{
156 return block_write_full_page(page, bfs_get_block, wbc);
157}
158
159static int bfs_readpage(struct file *file, struct page *page)
160{
161 return block_read_full_page(page, bfs_get_block);
162}
163
Nick Piggineedcbba2007-10-16 01:25:11 -0700164static int bfs_write_begin(struct file *file, struct address_space *mapping,
165 loff_t pos, unsigned len, unsigned flags,
166 struct page **pagep, void **fsdata)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700167{
Christoph Hellwig155130a2010-06-04 11:29:58 +0200168 int ret;
169
170 ret = block_write_begin(mapping, pos, len, flags, pagep,
171 bfs_get_block);
172 if (unlikely(ret)) {
173 loff_t isize = mapping->host->i_size;
174 if (pos + len > isize)
175 vmtruncate(mapping->host, isize);
176 }
177
178 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700179}
180
181static sector_t bfs_bmap(struct address_space *mapping, sector_t block)
182{
183 return generic_block_bmap(mapping, block, bfs_get_block);
184}
185
Christoph Hellwigf5e54d62006-06-28 04:26:44 -0700186const struct address_space_operations bfs_aops = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700187 .readpage = bfs_readpage,
188 .writepage = bfs_writepage,
Nick Piggineedcbba2007-10-16 01:25:11 -0700189 .write_begin = bfs_write_begin,
190 .write_end = generic_write_end,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700191 .bmap = bfs_bmap,
192};
193
Arjan van de Ven754661f2007-02-12 00:55:38 -0800194const struct inode_operations bfs_file_inops;