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Linux kernel mirror (for testing)
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kernel
os
linux
1/*
2 * linux/fs/ext2/xip.c
3 *
4 * Copyright (C) 2005 IBM Corporation
5 * Author: Carsten Otte (cotte@de.ibm.com)
6 */
7
8#include <linux/mm.h>
9#include <linux/fs.h>
10#include <linux/genhd.h>
11#include <linux/buffer_head.h>
12#include <linux/ext2_fs_sb.h>
13#include <linux/ext2_fs.h>
14#include "ext2.h"
15#include "xip.h"
16
17static inline int
18__inode_direct_access(struct inode *inode, sector_t sector,
19 unsigned long *data)
20{
21 BUG_ON(!inode->i_sb->s_bdev->bd_disk->fops->direct_access);
22 return inode->i_sb->s_bdev->bd_disk->fops
23 ->direct_access(inode->i_sb->s_bdev,sector,data);
24}
25
26static inline int
27__ext2_get_sector(struct inode *inode, sector_t offset, int create,
28 sector_t *result)
29{
30 struct buffer_head tmp;
31 int rc;
32
33 memset(&tmp, 0, sizeof(struct buffer_head));
34 rc = ext2_get_block(inode, offset/ (PAGE_SIZE/512), &tmp,
35 create);
36 *result = tmp.b_blocknr;
37
38 /* did we get a sparse block (hole in the file)? */
39 if (!tmp.b_blocknr && !rc) {
40 BUG_ON(create);
41 rc = -ENODATA;
42 }
43
44 return rc;
45}
46
47int
48ext2_clear_xip_target(struct inode *inode, int block)
49{
50 sector_t sector = block * (PAGE_SIZE/512);
51 unsigned long data;
52 int rc;
53
54 rc = __inode_direct_access(inode, sector, &data);
55 if (!rc)
56 clear_page((void*)data);
57 return rc;
58}
59
60void ext2_xip_verify_sb(struct super_block *sb)
61{
62 struct ext2_sb_info *sbi = EXT2_SB(sb);
63
64 if ((sbi->s_mount_opt & EXT2_MOUNT_XIP) &&
65 !sb->s_bdev->bd_disk->fops->direct_access) {
66 sbi->s_mount_opt &= (~EXT2_MOUNT_XIP);
67 ext2_warning(sb, __FUNCTION__,
68 "ignoring xip option - not supported by bdev");
69 }
70}
71
72struct page *
73ext2_get_xip_page(struct address_space *mapping, sector_t offset,
74 int create)
75{
76 int rc;
77 unsigned long data;
78 sector_t sector;
79
80 /* first, retrieve the sector number */
81 rc = __ext2_get_sector(mapping->host, offset, create, §or);
82 if (rc)
83 goto error;
84
85 /* retrieve address of the target data */
86 rc = __inode_direct_access
87 (mapping->host, sector * (PAGE_SIZE/512), &data);
88 if (!rc)
89 return virt_to_page(data);
90
91 error:
92 return ERR_PTR(rc);
93}