Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael...
[linux-2.6.git] / fs / hfsplus / wrapper.c
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 <asm/unaligned.h>
16
17 #include "hfsplus_fs.h"
18 #include "hfsplus_raw.h"
19
20 struct hfsplus_wd {
21         u32 ablk_size;
22         u16 ablk_start;
23         u16 embed_start;
24         u16 embed_count;
25 };
26
27 static int hfsplus_read_mdb(void *bufptr, struct hfsplus_wd *wd)
28 {
29         u32 extent;
30         u16 attrib;
31         __be16 sig;
32
33         sig = *(__be16 *)(bufptr + HFSP_WRAPOFF_EMBEDSIG);
34         if (sig != cpu_to_be16(HFSPLUS_VOLHEAD_SIG) &&
35             sig != cpu_to_be16(HFSPLUS_VOLHEAD_SIGX))
36                 return 0;
37
38         attrib = be16_to_cpu(*(__be16 *)(bufptr + HFSP_WRAPOFF_ATTRIB));
39         if (!(attrib & HFSP_WRAP_ATTRIB_SLOCK) ||
40            !(attrib & HFSP_WRAP_ATTRIB_SPARED))
41                 return 0;
42
43         wd->ablk_size = be32_to_cpu(*(__be32 *)(bufptr + HFSP_WRAPOFF_ABLKSIZE));
44         if (wd->ablk_size < HFSPLUS_SECTOR_SIZE)
45                 return 0;
46         if (wd->ablk_size % HFSPLUS_SECTOR_SIZE)
47                 return 0;
48         wd->ablk_start = be16_to_cpu(*(__be16 *)(bufptr + HFSP_WRAPOFF_ABLKSTART));
49
50         extent = get_unaligned_be32(bufptr + HFSP_WRAPOFF_EMBEDEXT);
51         wd->embed_start = (extent >> 16) & 0xFFFF;
52         wd->embed_count = extent & 0xFFFF;
53
54         return 1;
55 }
56
57 static int hfsplus_get_last_session(struct super_block *sb,
58                                     sector_t *start, sector_t *size)
59 {
60         struct cdrom_multisession ms_info;
61         struct cdrom_tocentry te;
62         int res;
63
64         /* default values */
65         *start = 0;
66         *size = sb->s_bdev->bd_inode->i_size >> 9;
67
68         if (HFSPLUS_SB(sb)->session >= 0) {
69                 te.cdte_track = HFSPLUS_SB(sb)->session;
70                 te.cdte_format = CDROM_LBA;
71                 res = ioctl_by_bdev(sb->s_bdev, CDROMREADTOCENTRY, (unsigned long)&te);
72                 if (!res && (te.cdte_ctrl & CDROM_DATA_TRACK) == 4) {
73                         *start = (sector_t)te.cdte_addr.lba << 2;
74                         return 0;
75                 }
76                 printk(KERN_ERR "hfs: invalid session number or type of track\n");
77                 return -EINVAL;
78         }
79         ms_info.addr_format = CDROM_LBA;
80         res = ioctl_by_bdev(sb->s_bdev, CDROMMULTISESSION, (unsigned long)&ms_info);
81         if (!res && ms_info.xa_flag)
82                 *start = (sector_t)ms_info.addr.lba << 2;
83         return 0;
84 }
85
86 /* Find the volume header and fill in some minimum bits in superblock */
87 /* Takes in super block, returns true if good data read */
88 int hfsplus_read_wrapper(struct super_block *sb)
89 {
90         struct hfsplus_sb_info *sbi = HFSPLUS_SB(sb);
91         struct buffer_head *bh;
92         struct hfsplus_vh *vhdr;
93         struct hfsplus_wd wd;
94         sector_t part_start, part_size;
95         u32 blocksize;
96
97         blocksize = sb_min_blocksize(sb, HFSPLUS_SECTOR_SIZE);
98         if (!blocksize)
99                 return -EINVAL;
100
101         if (hfsplus_get_last_session(sb, &part_start, &part_size))
102                 return -EINVAL;
103         if ((u64)part_start + part_size > 0x100000000ULL) {
104                 pr_err("hfs: volumes larger than 2TB are not supported yet\n");
105                 return -EINVAL;
106         }
107         while (1) {
108                 bh = sb_bread512(sb, part_start + HFSPLUS_VOLHEAD_SECTOR, vhdr);
109                 if (!bh)
110                         return -EIO;
111
112                 if (vhdr->signature == cpu_to_be16(HFSP_WRAP_MAGIC)) {
113                         if (!hfsplus_read_mdb(vhdr, &wd))
114                                 goto error;
115                         wd.ablk_size >>= HFSPLUS_SECTOR_SHIFT;
116                         part_start += wd.ablk_start + wd.embed_start * wd.ablk_size;
117                         part_size = wd.embed_count * wd.ablk_size;
118                         brelse(bh);
119                         bh = sb_bread512(sb, part_start + HFSPLUS_VOLHEAD_SECTOR, vhdr);
120                         if (!bh)
121                                 return -EIO;
122                 }
123                 if (vhdr->signature == cpu_to_be16(HFSPLUS_VOLHEAD_SIG))
124                         break;
125                 if (vhdr->signature == cpu_to_be16(HFSPLUS_VOLHEAD_SIGX)) {
126                         set_bit(HFSPLUS_SB_HFSX, &sbi->flags);
127                         break;
128                 }
129                 brelse(bh);
130
131                 /* check for a partition block
132                  * (should do this only for cdrom/loop though)
133                  */
134                 if (hfs_part_find(sb, &part_start, &part_size))
135                         return -EINVAL;
136         }
137
138         blocksize = be32_to_cpu(vhdr->blocksize);
139         brelse(bh);
140
141         /* block size must be at least as large as a sector
142          * and a multiple of 2
143          */
144         if (blocksize < HFSPLUS_SECTOR_SIZE ||
145             ((blocksize - 1) & blocksize))
146                 return -EINVAL;
147         sbi->alloc_blksz = blocksize;
148         sbi->alloc_blksz_shift = 0;
149         while ((blocksize >>= 1) != 0)
150                 sbi->alloc_blksz_shift++;
151         blocksize = min(sbi->alloc_blksz, (u32)PAGE_SIZE);
152
153         /* align block size to block offset */
154         while (part_start & ((blocksize >> HFSPLUS_SECTOR_SHIFT) - 1))
155                 blocksize >>= 1;
156
157         if (sb_set_blocksize(sb, blocksize) != blocksize) {
158                 printk(KERN_ERR "hfs: unable to set blocksize to %u!\n", blocksize);
159                 return -EINVAL;
160         }
161
162         sbi->blockoffset =
163                 part_start >> (sb->s_blocksize_bits - HFSPLUS_SECTOR_SHIFT);
164         sbi->sect_count = part_size;
165         sbi->fs_shift = sbi->alloc_blksz_shift - sb->s_blocksize_bits;
166
167         bh = sb_bread512(sb, part_start + HFSPLUS_VOLHEAD_SECTOR, vhdr);
168         if (!bh)
169                 return -EIO;
170
171         /* should still be the same... */
172         if (test_bit(HFSPLUS_SB_HFSX, &sbi->flags)) {
173                 if (vhdr->signature != cpu_to_be16(HFSPLUS_VOLHEAD_SIGX))
174                         goto error;
175         } else {
176                 if (vhdr->signature != cpu_to_be16(HFSPLUS_VOLHEAD_SIG))
177                         goto error;
178         }
179
180         sbi->s_vhbh = bh;
181         sbi->s_vhdr = vhdr;
182
183         return 0;
184  error:
185         brelse(bh);
186         return -EINVAL;
187 }