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1da177e4 LT |
1 | /* |
2 | * linux/fs/hfsplus/wrapper.c | |
3 | * | |
4 | * Copyright (C) 2001 | |
5 | * Brad Boyer (flar@allandria.com) | |
6 | * (C) 2003 Ardis Technologies <roman@ardistech.com> | |
7 | * | |
8 | * Handling of HFS wrappers around HFS+ volumes | |
9 | */ | |
10 | ||
11 | #include <linux/fs.h> | |
12 | #include <linux/blkdev.h> | |
13 | #include <linux/cdrom.h> | |
14 | #include <linux/genhd.h> | |
15 | #include <linux/version.h> | |
16 | #include <asm/unaligned.h> | |
17 | ||
18 | #include "hfsplus_fs.h" | |
19 | #include "hfsplus_raw.h" | |
20 | ||
21 | struct hfsplus_wd { | |
22 | u32 ablk_size; | |
23 | u16 ablk_start; | |
24 | u16 embed_start; | |
25 | u16 embed_count; | |
26 | }; | |
27 | ||
28 | static int hfsplus_read_mdb(void *bufptr, struct hfsplus_wd *wd) | |
29 | { | |
30 | u32 extent; | |
31 | u16 attrib; | |
32 | ||
33 | if (be16_to_cpu(*(__be16 *)(bufptr + HFSP_WRAPOFF_EMBEDSIG)) != HFSPLUS_VOLHEAD_SIG) | |
34 | return 0; | |
35 | ||
36 | attrib = be16_to_cpu(*(__be16 *)(bufptr + HFSP_WRAPOFF_ATTRIB)); | |
37 | if (!(attrib & HFSP_WRAP_ATTRIB_SLOCK) || | |
38 | !(attrib & HFSP_WRAP_ATTRIB_SPARED)) | |
39 | return 0; | |
40 | ||
41 | wd->ablk_size = be32_to_cpu(*(__be32 *)(bufptr + HFSP_WRAPOFF_ABLKSIZE)); | |
42 | if (wd->ablk_size < HFSPLUS_SECTOR_SIZE) | |
43 | return 0; | |
44 | if (wd->ablk_size % HFSPLUS_SECTOR_SIZE) | |
45 | return 0; | |
46 | wd->ablk_start = be16_to_cpu(*(__be16 *)(bufptr + HFSP_WRAPOFF_ABLKSTART)); | |
47 | ||
48 | extent = be32_to_cpu(get_unaligned((__be32 *)(bufptr + HFSP_WRAPOFF_EMBEDEXT))); | |
49 | wd->embed_start = (extent >> 16) & 0xFFFF; | |
50 | wd->embed_count = extent & 0xFFFF; | |
51 | ||
52 | return 1; | |
53 | } | |
54 | ||
55 | static int hfsplus_get_last_session(struct super_block *sb, | |
56 | sector_t *start, sector_t *size) | |
57 | { | |
58 | struct cdrom_multisession ms_info; | |
59 | struct cdrom_tocentry te; | |
60 | int res; | |
61 | ||
62 | /* default values */ | |
63 | *start = 0; | |
64 | *size = sb->s_bdev->bd_inode->i_size >> 9; | |
65 | ||
66 | if (HFSPLUS_SB(sb).session >= 0) { | |
67 | te.cdte_track = HFSPLUS_SB(sb).session; | |
68 | te.cdte_format = CDROM_LBA; | |
69 | res = ioctl_by_bdev(sb->s_bdev, CDROMREADTOCENTRY, (unsigned long)&te); | |
70 | if (!res && (te.cdte_ctrl & CDROM_DATA_TRACK) == 4) { | |
71 | *start = (sector_t)te.cdte_addr.lba << 2; | |
72 | return 0; | |
73 | } | |
74 | printk(KERN_ERR "HFS: Invalid session number or type of track\n"); | |
75 | return -EINVAL; | |
76 | } | |
77 | ms_info.addr_format = CDROM_LBA; | |
78 | res = ioctl_by_bdev(sb->s_bdev, CDROMMULTISESSION, (unsigned long)&ms_info); | |
79 | if (!res && ms_info.xa_flag) | |
80 | *start = (sector_t)ms_info.addr.lba << 2; | |
81 | return 0; | |
82 | } | |
83 | ||
84 | /* Find the volume header and fill in some minimum bits in superblock */ | |
85 | /* Takes in super block, returns true if good data read */ | |
86 | int hfsplus_read_wrapper(struct super_block *sb) | |
87 | { | |
88 | struct buffer_head *bh; | |
89 | struct hfsplus_vh *vhdr; | |
90 | struct hfsplus_wd wd; | |
91 | sector_t part_start, part_size; | |
92 | u32 blocksize; | |
93 | ||
94 | blocksize = sb_min_blocksize(sb, HFSPLUS_SECTOR_SIZE); | |
95 | if (!blocksize) | |
96 | return -EINVAL; | |
97 | ||
98 | if (hfsplus_get_last_session(sb, &part_start, &part_size)) | |
99 | return -EINVAL; | |
100 | while (1) { | |
101 | bh = sb_bread512(sb, part_start + HFSPLUS_VOLHEAD_SECTOR, vhdr); | |
102 | if (!bh) | |
103 | return -EIO; | |
104 | ||
105 | if (vhdr->signature == cpu_to_be16(HFSP_WRAP_MAGIC)) { | |
106 | if (!hfsplus_read_mdb(vhdr, &wd)) | |
107 | goto error; | |
108 | wd.ablk_size >>= HFSPLUS_SECTOR_SHIFT; | |
109 | part_start += wd.ablk_start + wd.embed_start * wd.ablk_size; | |
110 | part_size = wd.embed_count * wd.ablk_size; | |
111 | brelse(bh); | |
112 | bh = sb_bread512(sb, part_start + HFSPLUS_VOLHEAD_SECTOR, vhdr); | |
113 | if (!bh) | |
114 | return -EIO; | |
115 | } | |
116 | if (vhdr->signature == cpu_to_be16(HFSPLUS_VOLHEAD_SIG)) | |
117 | break; | |
118 | brelse(bh); | |
119 | ||
120 | /* check for a partition block | |
121 | * (should do this only for cdrom/loop though) | |
122 | */ | |
123 | if (hfs_part_find(sb, &part_start, &part_size)) | |
124 | return -EINVAL; | |
125 | } | |
126 | ||
127 | blocksize = be32_to_cpu(vhdr->blocksize); | |
128 | brelse(bh); | |
129 | ||
130 | /* block size must be at least as large as a sector | |
131 | * and a multiple of 2 | |
132 | */ | |
133 | if (blocksize < HFSPLUS_SECTOR_SIZE || | |
134 | ((blocksize - 1) & blocksize)) | |
135 | return -EINVAL; | |
136 | HFSPLUS_SB(sb).alloc_blksz = blocksize; | |
137 | HFSPLUS_SB(sb).alloc_blksz_shift = 0; | |
138 | while ((blocksize >>= 1) != 0) | |
139 | HFSPLUS_SB(sb).alloc_blksz_shift++; | |
140 | blocksize = min(HFSPLUS_SB(sb).alloc_blksz, (u32)PAGE_SIZE); | |
141 | ||
142 | /* align block size to block offset */ | |
143 | while (part_start & ((blocksize >> HFSPLUS_SECTOR_SHIFT) - 1)) | |
144 | blocksize >>= 1; | |
145 | ||
146 | if (sb_set_blocksize(sb, blocksize) != blocksize) { | |
147 | printk("HFS+: unable to blocksize to %u!\n", blocksize); | |
148 | return -EINVAL; | |
149 | } | |
150 | ||
151 | HFSPLUS_SB(sb).blockoffset = part_start >> | |
152 | (sb->s_blocksize_bits - HFSPLUS_SECTOR_SHIFT); | |
153 | HFSPLUS_SB(sb).sect_count = part_size; | |
154 | HFSPLUS_SB(sb).fs_shift = HFSPLUS_SB(sb).alloc_blksz_shift - | |
155 | sb->s_blocksize_bits; | |
156 | ||
157 | bh = sb_bread512(sb, part_start + HFSPLUS_VOLHEAD_SECTOR, vhdr); | |
158 | if (!bh) | |
159 | return -EIO; | |
160 | ||
161 | /* should still be the same... */ | |
162 | if (be16_to_cpu(vhdr->signature) != HFSPLUS_VOLHEAD_SIG) | |
163 | goto error; | |
164 | HFSPLUS_SB(sb).s_vhbh = bh; | |
165 | HFSPLUS_SB(sb).s_vhdr = vhdr; | |
166 | ||
167 | return 0; | |
168 | error: | |
169 | brelse(bh); | |
170 | return -EINVAL; | |
171 | } |