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
hfsplus_end_io_sync(struct bio * bio,int err)27 static void hfsplus_end_io_sync(struct bio *bio, int err)
28 {
29 if (err)
30 clear_bit(BIO_UPTODATE, &bio->bi_flags);
31 complete(bio->bi_private);
32 }
33
34 /*
35 * hfsplus_submit_bio - Perfrom block I/O
36 * @sb: super block of volume for I/O
37 * @sector: block to read or write, for blocks of HFSPLUS_SECTOR_SIZE bytes
38 * @buf: buffer for I/O
39 * @data: output pointer for location of requested data
40 * @rw: direction of I/O
41 *
42 * The unit of I/O is hfsplus_min_io_size(sb), which may be bigger than
43 * HFSPLUS_SECTOR_SIZE, and @buf must be sized accordingly. On reads
44 * @data will return a pointer to the start of the requested sector,
45 * which may not be the same location as @buf.
46 *
47 * If @sector is not aligned to the bdev logical block size it will
48 * be rounded down. For writes this means that @buf should contain data
49 * that starts at the rounded-down address. As long as the data was
50 * read using hfsplus_submit_bio() and the same buffer is used things
51 * will work correctly.
52 */
hfsplus_submit_bio(struct super_block * sb,sector_t sector,void * buf,void ** data,int rw)53 int hfsplus_submit_bio(struct super_block *sb, sector_t sector,
54 void *buf, void **data, int rw)
55 {
56 DECLARE_COMPLETION_ONSTACK(wait);
57 struct bio *bio;
58 int ret = 0;
59 u64 io_size;
60 loff_t start;
61 int offset;
62
63 /*
64 * Align sector to hardware sector size and find offset. We
65 * assume that io_size is a power of two, which _should_
66 * be true.
67 */
68 io_size = hfsplus_min_io_size(sb);
69 start = (loff_t)sector << HFSPLUS_SECTOR_SHIFT;
70 offset = start & (io_size - 1);
71 sector &= ~((io_size >> HFSPLUS_SECTOR_SHIFT) - 1);
72
73 bio = bio_alloc(GFP_NOIO, 1);
74 bio->bi_sector = sector;
75 bio->bi_bdev = sb->s_bdev;
76 bio->bi_end_io = hfsplus_end_io_sync;
77 bio->bi_private = &wait;
78
79 if (!(rw & WRITE) && data)
80 *data = (u8 *)buf + offset;
81
82 while (io_size > 0) {
83 unsigned int page_offset = offset_in_page(buf);
84 unsigned int len = min_t(unsigned int, PAGE_SIZE - page_offset,
85 io_size);
86
87 ret = bio_add_page(bio, virt_to_page(buf), len, page_offset);
88 if (ret != len) {
89 ret = -EIO;
90 goto out;
91 }
92 io_size -= len;
93 buf = (u8 *)buf + len;
94 }
95
96 submit_bio(rw, bio);
97 wait_for_completion(&wait);
98
99 if (!bio_flagged(bio, BIO_UPTODATE))
100 ret = -EIO;
101
102 out:
103 bio_put(bio);
104 return ret < 0 ? ret : 0;
105 }
106
hfsplus_read_mdb(void * bufptr,struct hfsplus_wd * wd)107 static int hfsplus_read_mdb(void *bufptr, struct hfsplus_wd *wd)
108 {
109 u32 extent;
110 u16 attrib;
111 __be16 sig;
112
113 sig = *(__be16 *)(bufptr + HFSP_WRAPOFF_EMBEDSIG);
114 if (sig != cpu_to_be16(HFSPLUS_VOLHEAD_SIG) &&
115 sig != cpu_to_be16(HFSPLUS_VOLHEAD_SIGX))
116 return 0;
117
118 attrib = be16_to_cpu(*(__be16 *)(bufptr + HFSP_WRAPOFF_ATTRIB));
119 if (!(attrib & HFSP_WRAP_ATTRIB_SLOCK) ||
120 !(attrib & HFSP_WRAP_ATTRIB_SPARED))
121 return 0;
122
123 wd->ablk_size =
124 be32_to_cpu(*(__be32 *)(bufptr + HFSP_WRAPOFF_ABLKSIZE));
125 if (wd->ablk_size < HFSPLUS_SECTOR_SIZE)
126 return 0;
127 if (wd->ablk_size % HFSPLUS_SECTOR_SIZE)
128 return 0;
129 wd->ablk_start =
130 be16_to_cpu(*(__be16 *)(bufptr + HFSP_WRAPOFF_ABLKSTART));
131
132 extent = get_unaligned_be32(bufptr + HFSP_WRAPOFF_EMBEDEXT);
133 wd->embed_start = (extent >> 16) & 0xFFFF;
134 wd->embed_count = extent & 0xFFFF;
135
136 return 1;
137 }
138
hfsplus_get_last_session(struct super_block * sb,sector_t * start,sector_t * size)139 static int hfsplus_get_last_session(struct super_block *sb,
140 sector_t *start, sector_t *size)
141 {
142 struct cdrom_multisession ms_info;
143 struct cdrom_tocentry te;
144 int res;
145
146 /* default values */
147 *start = 0;
148 *size = sb->s_bdev->bd_inode->i_size >> 9;
149
150 if (HFSPLUS_SB(sb)->session >= 0) {
151 te.cdte_track = HFSPLUS_SB(sb)->session;
152 te.cdte_format = CDROM_LBA;
153 res = ioctl_by_bdev(sb->s_bdev,
154 CDROMREADTOCENTRY, (unsigned long)&te);
155 if (!res && (te.cdte_ctrl & CDROM_DATA_TRACK) == 4) {
156 *start = (sector_t)te.cdte_addr.lba << 2;
157 return 0;
158 }
159 printk(KERN_ERR "hfs: invalid session number or type of track\n");
160 return -EINVAL;
161 }
162 ms_info.addr_format = CDROM_LBA;
163 res = ioctl_by_bdev(sb->s_bdev, CDROMMULTISESSION,
164 (unsigned long)&ms_info);
165 if (!res && ms_info.xa_flag)
166 *start = (sector_t)ms_info.addr.lba << 2;
167 return 0;
168 }
169
170 /* Find the volume header and fill in some minimum bits in superblock */
171 /* Takes in super block, returns true if good data read */
hfsplus_read_wrapper(struct super_block * sb)172 int hfsplus_read_wrapper(struct super_block *sb)
173 {
174 struct hfsplus_sb_info *sbi = HFSPLUS_SB(sb);
175 struct hfsplus_wd wd;
176 sector_t part_start, part_size;
177 u32 blocksize;
178 int error = 0;
179
180 error = -EINVAL;
181 blocksize = sb_min_blocksize(sb, HFSPLUS_SECTOR_SIZE);
182 if (!blocksize)
183 goto out;
184
185 if (hfsplus_get_last_session(sb, &part_start, &part_size))
186 goto out;
187
188 error = -ENOMEM;
189 sbi->s_vhdr_buf = kmalloc(hfsplus_min_io_size(sb), GFP_KERNEL);
190 if (!sbi->s_vhdr_buf)
191 goto out;
192 sbi->s_backup_vhdr_buf = kmalloc(hfsplus_min_io_size(sb), GFP_KERNEL);
193 if (!sbi->s_backup_vhdr_buf)
194 goto out_free_vhdr;
195
196 reread:
197 error = hfsplus_submit_bio(sb, part_start + HFSPLUS_VOLHEAD_SECTOR,
198 sbi->s_vhdr_buf, (void **)&sbi->s_vhdr,
199 READ);
200 if (error)
201 goto out_free_backup_vhdr;
202
203 error = -EINVAL;
204 switch (sbi->s_vhdr->signature) {
205 case cpu_to_be16(HFSPLUS_VOLHEAD_SIGX):
206 set_bit(HFSPLUS_SB_HFSX, &sbi->flags);
207 /*FALLTHRU*/
208 case cpu_to_be16(HFSPLUS_VOLHEAD_SIG):
209 break;
210 case cpu_to_be16(HFSP_WRAP_MAGIC):
211 if (!hfsplus_read_mdb(sbi->s_vhdr, &wd))
212 goto out_free_backup_vhdr;
213 wd.ablk_size >>= HFSPLUS_SECTOR_SHIFT;
214 part_start += (sector_t)wd.ablk_start +
215 (sector_t)wd.embed_start * wd.ablk_size;
216 part_size = (sector_t)wd.embed_count * wd.ablk_size;
217 goto reread;
218 default:
219 /*
220 * Check for a partition block.
221 *
222 * (should do this only for cdrom/loop though)
223 */
224 if (hfs_part_find(sb, &part_start, &part_size))
225 goto out_free_backup_vhdr;
226 goto reread;
227 }
228
229 error = hfsplus_submit_bio(sb, part_start + part_size - 2,
230 sbi->s_backup_vhdr_buf,
231 (void **)&sbi->s_backup_vhdr, READ);
232 if (error)
233 goto out_free_backup_vhdr;
234
235 error = -EINVAL;
236 if (sbi->s_backup_vhdr->signature != sbi->s_vhdr->signature) {
237 printk(KERN_WARNING
238 "hfs: invalid secondary volume header\n");
239 goto out_free_backup_vhdr;
240 }
241
242 blocksize = be32_to_cpu(sbi->s_vhdr->blocksize);
243
244 /*
245 * Block size must be at least as large as a sector and a multiple of 2.
246 */
247 if (blocksize < HFSPLUS_SECTOR_SIZE || ((blocksize - 1) & blocksize))
248 goto out_free_backup_vhdr;
249 sbi->alloc_blksz = blocksize;
250 sbi->alloc_blksz_shift = 0;
251 while ((blocksize >>= 1) != 0)
252 sbi->alloc_blksz_shift++;
253 blocksize = min(sbi->alloc_blksz, (u32)PAGE_SIZE);
254
255 /*
256 * Align block size to block offset.
257 */
258 while (part_start & ((blocksize >> HFSPLUS_SECTOR_SHIFT) - 1))
259 blocksize >>= 1;
260
261 if (sb_set_blocksize(sb, blocksize) != blocksize) {
262 printk(KERN_ERR "hfs: unable to set blocksize to %u!\n",
263 blocksize);
264 goto out_free_backup_vhdr;
265 }
266
267 sbi->blockoffset =
268 part_start >> (sb->s_blocksize_bits - HFSPLUS_SECTOR_SHIFT);
269 sbi->part_start = part_start;
270 sbi->sect_count = part_size;
271 sbi->fs_shift = sbi->alloc_blksz_shift - sb->s_blocksize_bits;
272 return 0;
273
274 out_free_backup_vhdr:
275 kfree(sbi->s_backup_vhdr_buf);
276 out_free_vhdr:
277 kfree(sbi->s_vhdr_buf);
278 out:
279 return error;
280 }
281