Btrfs: make set/get functions for the super compat_ro flags use compat_ro
[linux-2.6.git] / fs / ext2 / xip.c
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 <linux/blkdev.h>
15 #include "ext2.h"
16 #include "xip.h"
17
18 static inline int
19 __inode_direct_access(struct inode *inode, sector_t block,
20                       void **kaddr, unsigned long *pfn)
21 {
22         struct block_device *bdev = inode->i_sb->s_bdev;
23         const struct block_device_operations *ops = bdev->bd_disk->fops;
24         sector_t sector;
25
26         sector = block * (PAGE_SIZE / 512); /* ext2 block to bdev sector */
27
28         BUG_ON(!ops->direct_access);
29         return ops->direct_access(bdev, sector, kaddr, pfn);
30 }
31
32 static inline int
33 __ext2_get_block(struct inode *inode, pgoff_t pgoff, int create,
34                    sector_t *result)
35 {
36         struct buffer_head tmp;
37         int rc;
38
39         memset(&tmp, 0, sizeof(struct buffer_head));
40         rc = ext2_get_block(inode, pgoff, &tmp, create);
41         *result = tmp.b_blocknr;
42
43         /* did we get a sparse block (hole in the file)? */
44         if (!tmp.b_blocknr && !rc) {
45                 BUG_ON(create);
46                 rc = -ENODATA;
47         }
48
49         return rc;
50 }
51
52 int
53 ext2_clear_xip_target(struct inode *inode, sector_t block)
54 {
55         void *kaddr;
56         unsigned long pfn;
57         int rc;
58
59         rc = __inode_direct_access(inode, block, &kaddr, &pfn);
60         if (!rc)
61                 clear_page(kaddr);
62         return rc;
63 }
64
65 void ext2_xip_verify_sb(struct super_block *sb)
66 {
67         struct ext2_sb_info *sbi = EXT2_SB(sb);
68
69         if ((sbi->s_mount_opt & EXT2_MOUNT_XIP) &&
70             !sb->s_bdev->bd_disk->fops->direct_access) {
71                 sbi->s_mount_opt &= (~EXT2_MOUNT_XIP);
72                 ext2_warning(sb, __func__,
73                              "ignoring xip option - not supported by bdev");
74         }
75 }
76
77 int ext2_get_xip_mem(struct address_space *mapping, pgoff_t pgoff, int create,
78                                 void **kmem, unsigned long *pfn)
79 {
80         int rc;
81         sector_t block;
82
83         /* first, retrieve the sector number */
84         rc = __ext2_get_block(mapping->host, pgoff, create, &block);
85         if (rc)
86                 return rc;
87
88         /* retrieve address of the target data */
89         rc = __inode_direct_access(mapping->host, block, kmem, pfn);
90         return rc;
91 }