xref: /linux/fs/befs/super.c (revision 0dd9ac63ce26ec87b080ca9c3e6efed33c23ace6)
1 /*
2  * super.c
3  *
4  * Copyright (C) 2001-2002 Will Dyson <will_dyson@pobox.com>
5  *
6  * Licensed under the GNU GPL. See the file COPYING for details.
7  *
8  */
9 
10 #include <linux/fs.h>
11 #include <asm/page.h> /* for PAGE_SIZE */
12 
13 #include "befs.h"
14 #include "super.h"
15 
16 /**
17  * load_befs_sb -- Read from disk and properly byteswap all the fields
18  * of the befs superblock
19  *
20  *
21  *
22  *
23  */
24 int
25 befs_load_sb(struct super_block *sb, befs_super_block * disk_sb)
26 {
27 	befs_sb_info *befs_sb = BEFS_SB(sb);
28 
29 	/* Check the byte order of the filesystem */
30 	if (disk_sb->fs_byte_order == BEFS_BYTEORDER_NATIVE_LE)
31 	    befs_sb->byte_order = BEFS_BYTESEX_LE;
32 	else if (disk_sb->fs_byte_order == BEFS_BYTEORDER_NATIVE_BE)
33 	    befs_sb->byte_order = BEFS_BYTESEX_BE;
34 
35 	befs_sb->magic1 = fs32_to_cpu(sb, disk_sb->magic1);
36 	befs_sb->magic2 = fs32_to_cpu(sb, disk_sb->magic2);
37 	befs_sb->magic3 = fs32_to_cpu(sb, disk_sb->magic3);
38 	befs_sb->block_size = fs32_to_cpu(sb, disk_sb->block_size);
39 	befs_sb->block_shift = fs32_to_cpu(sb, disk_sb->block_shift);
40 	befs_sb->num_blocks = fs64_to_cpu(sb, disk_sb->num_blocks);
41 	befs_sb->used_blocks = fs64_to_cpu(sb, disk_sb->used_blocks);
42 	befs_sb->inode_size = fs32_to_cpu(sb, disk_sb->inode_size);
43 
44 	befs_sb->blocks_per_ag = fs32_to_cpu(sb, disk_sb->blocks_per_ag);
45 	befs_sb->ag_shift = fs32_to_cpu(sb, disk_sb->ag_shift);
46 	befs_sb->num_ags = fs32_to_cpu(sb, disk_sb->num_ags);
47 
48 	befs_sb->log_blocks = fsrun_to_cpu(sb, disk_sb->log_blocks);
49 	befs_sb->log_start = fs64_to_cpu(sb, disk_sb->log_start);
50 	befs_sb->log_end = fs64_to_cpu(sb, disk_sb->log_end);
51 
52 	befs_sb->root_dir = fsrun_to_cpu(sb, disk_sb->root_dir);
53 	befs_sb->indices = fsrun_to_cpu(sb, disk_sb->indices);
54 	befs_sb->nls = NULL;
55 
56 	return BEFS_OK;
57 }
58 
59 int
60 befs_check_sb(struct super_block *sb)
61 {
62 	befs_sb_info *befs_sb = BEFS_SB(sb);
63 
64 	/* Check magic headers of super block */
65 	if ((befs_sb->magic1 != BEFS_SUPER_MAGIC1)
66 	    || (befs_sb->magic2 != BEFS_SUPER_MAGIC2)
67 	    || (befs_sb->magic3 != BEFS_SUPER_MAGIC3)) {
68 		befs_error(sb, "invalid magic header");
69 		return BEFS_ERR;
70 	}
71 
72 	/*
73 	 * Check blocksize of BEFS.
74 	 *
75 	 * Blocksize of BEFS is 1024, 2048, 4096 or 8192.
76 	 */
77 
78 	if ((befs_sb->block_size != 1024)
79 	    && (befs_sb->block_size != 2048)
80 	    && (befs_sb->block_size != 4096)
81 	    && (befs_sb->block_size != 8192)) {
82 		befs_error(sb, "invalid blocksize: %u", befs_sb->block_size);
83 		return BEFS_ERR;
84 	}
85 
86 	if (befs_sb->block_size > PAGE_SIZE) {
87 		befs_error(sb, "blocksize(%u) cannot be larger"
88 			   "than system pagesize(%lu)", befs_sb->block_size,
89 			   PAGE_SIZE);
90 		return BEFS_ERR;
91 	}
92 
93 	/*
94 	   * block_shift and block_size encode the same information
95 	   * in different ways as a consistency check.
96 	 */
97 
98 	if ((1 << befs_sb->block_shift) != befs_sb->block_size) {
99 		befs_error(sb, "block_shift disagrees with block_size. "
100 			   "Corruption likely.");
101 		return BEFS_ERR;
102 	}
103 
104 	if (befs_sb->log_start != befs_sb->log_end) {
105 		befs_error(sb, "Filesystem not clean! There are blocks in the "
106 			   "journal. You must boot into BeOS and mount this volume "
107 			   "to make it clean.");
108 		return BEFS_ERR;
109 	}
110 
111 	return BEFS_OK;
112 }
113