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 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 int hfsplus_submit_bio(struct block_device *bdev, sector_t sector,
  35                 void *data, int rw)
  36 {
  37         DECLARE_COMPLETION_ONSTACK(wait);
  38         struct bio *bio;
  39
  40         bio = bio_alloc(GFP_NOIO, 1);
  41         bio->bi_sector = sector;
  42         bio->bi_bdev = bdev;
  43         bio->bi_end_io = hfsplus_end_io_sync;
  44         bio->bi_private = &wait;
  45
  46         /*
  47          * We always submit one sector at a time, so bio_add_page must not fail.
  48          */
  49         if (bio_add_page(bio, virt_to_page(data), HFSPLUS_SECTOR_SIZE,
  50                          offset_in_page(data)) != HFSPLUS_SECTOR_SIZE)
  51                 BUG();
  52
  53         submit_bio(rw, bio);
  54         wait_for_completion(&wait);
  55
  56         if (!bio_flagged(bio, BIO_UPTODATE))
  57                 return -EIO;
  58         return 0;
  59 }
  60
  61 static int hfsplus_read_mdb(void *bufptr, struct hfsplus_wd *wd)
  62 {
  63         u32 extent;
  64         u16 attrib;
  65         __be16 sig;
  66
  67         sig = *(__be16 *)(bufptr + HFSP_WRAPOFF_EMBEDSIG);
  68         if (sig != cpu_to_be16(HFSPLUS_VOLHEAD_SIG) &&
  69             sig != cpu_to_be16(HFSPLUS_VOLHEAD_SIGX))
  70                 return 0;
  71
  72         attrib = be16_to_cpu(*(__be16 *)(bufptr + HFSP_WRAPOFF_ATTRIB));
  73         if (!(attrib & HFSP_WRAP_ATTRIB_SLOCK) ||
  74            !(attrib & HFSP_WRAP_ATTRIB_SPARED))
  75                 return 0;
  76
  77         wd->ablk_size =
  78                 be32_to_cpu(*(__be32 *)(bufptr + HFSP_WRAPOFF_ABLKSIZE));
  79         if (wd->ablk_size < HFSPLUS_SECTOR_SIZE)
  80                 return 0;
  81         if (wd->ablk_size % HFSPLUS_SECTOR_SIZE)
  82                 return 0;
  83         wd->ablk_start =
  84                 be16_to_cpu(*(__be16 *)(bufptr + HFSP_WRAPOFF_ABLKSTART));
  85
  86         extent = get_unaligned_be32(bufptr + HFSP_WRAPOFF_EMBEDEXT);
  87         wd->embed_start = (extent >> 16) & 0xFFFF;
  88         wd->embed_count = extent & 0xFFFF;
  89
  90         return 1;
  91 }
  92
  93 static int hfsplus_get_last_session(struct super_block *sb,
  94                                     sector_t *start, sector_t *size)
  95 {
  96         struct cdrom_multisession ms_info;
  97         struct cdrom_tocentry te;
  98         int res;
  99
 100         /* default values */
 101         *start = 0;
 102         *size = sb->s_bdev->bd_inode->i_size >> 9;
 103
 104         if (HFSPLUS_SB(sb)->session >= 0) {
 105                 te.cdte_track = HFSPLUS_SB(sb)->session;
 106                 te.cdte_format = CDROM_LBA;
 107                 res = ioctl_by_bdev(sb->s_bdev,
 108                         CDROMREADTOCENTRY, (unsigned long)&te);
 109                 if (!res && (te.cdte_ctrl & CDROM_DATA_TRACK) == 4) {
 110                         *start = (sector_t)te.cdte_addr.lba << 2;
 111                         return 0;
 112                 }
 113                 printk(KERN_ERR "hfs: invalid session number or type of track\n");
 114                 return -EINVAL;
 115         }
 116         ms_info.addr_format = CDROM_LBA;
 117         res = ioctl_by_bdev(sb->s_bdev, CDROMMULTISESSION,
 118                 (unsigned long)&ms_info);
 119         if (!res && ms_info.xa_flag)
 120                 *start = (sector_t)ms_info.addr.lba << 2;
 121         return 0;
 122 }
 123
 124 /* Find the volume header and fill in some minimum bits in superblock */
 125 /* Takes in super block, returns true if good data read */
 126 int hfsplus_read_wrapper(struct super_block *sb)
 127 {
 128         struct hfsplus_sb_info *sbi = HFSPLUS_SB(sb);
 129         struct hfsplus_wd wd;
 130         sector_t part_start, part_size;
 131         u32 blocksize;
 132         int error = 0;
 133
 134         error = -EINVAL;
 135         blocksize = sb_min_blocksize(sb, HFSPLUS_SECTOR_SIZE);
 136         if (!blocksize)
 137                 goto out;
 138
 139         if (hfsplus_get_last_session(sb, &part_start, &part_size))
 140                 goto out;
 141         if ((u64)part_start + part_size > 0x100000000ULL) {
 142                 pr_err("hfs: volumes larger than 2TB are not supported yet\n");
 143                 goto out;
 144         }
 145
 146         error = -ENOMEM;
 147         sbi->s_vhdr = kmalloc(HFSPLUS_SECTOR_SIZE, GFP_KERNEL);
 148         if (!sbi->s_vhdr)
 149                 goto out;
 150         sbi->s_backup_vhdr = kmalloc(HFSPLUS_SECTOR_SIZE, GFP_KERNEL);
 151         if (!sbi->s_backup_vhdr)
 152                 goto out_free_vhdr;
 153
 154 reread:
 155         error = hfsplus_submit_bio(sb->s_bdev,
 156                                    part_start + HFSPLUS_VOLHEAD_SECTOR,
 157                                    sbi->s_vhdr, READ);
 158         if (error)
 159                 goto out_free_backup_vhdr;
 160
 161         error = -EINVAL;
 162         switch (sbi->s_vhdr->signature) {
 163         case cpu_to_be16(HFSPLUS_VOLHEAD_SIGX):
 164                 set_bit(HFSPLUS_SB_HFSX, &sbi->flags);
 165                 /*FALLTHRU*/
 166         case cpu_to_be16(HFSPLUS_VOLHEAD_SIG):
 167                 break;
 168         case cpu_to_be16(HFSP_WRAP_MAGIC):
 169                 if (!hfsplus_read_mdb(sbi->s_vhdr, &wd))
 170                         goto out;
 171                 wd.ablk_size >>= HFSPLUS_SECTOR_SHIFT;
 172                 part_start += wd.ablk_start + wd.embed_start * wd.ablk_size;
 173                 part_size = wd.embed_count * wd.ablk_size;
 174                 goto reread;
 175         default:
 176                 /*
 177                  * Check for a partition block.
 178                  *
 179                  * (should do this only for cdrom/loop though)
 180                  */
 181                 if (hfs_part_find(sb, &part_start, &part_size))
 182                         goto out;
 183                 goto reread;
 184         }
 185
 186         error = hfsplus_submit_bio(sb->s_bdev,
 187                                    part_start + part_size - 2,
 188                                    sbi->s_backup_vhdr, READ);
 189         if (error)
 190                 goto out_free_backup_vhdr;
 191
 192         error = -EINVAL;
 193         if (sbi->s_backup_vhdr->signature != sbi->s_vhdr->signature) {
 194                 printk(KERN_WARNING
 195                         "hfs: invalid secondary volume header\n");
 196                 goto out_free_backup_vhdr;
 197         }
 198
 199         blocksize = be32_to_cpu(sbi->s_vhdr->blocksize);
 200
 201         /*
 202          * Block size must be at least as large as a sector and a multiple of 2.
 203          */
 204         if (blocksize < HFSPLUS_SECTOR_SIZE || ((blocksize - 1) & blocksize))
 205                 goto out_free_backup_vhdr;
 206         sbi->alloc_blksz = blocksize;
 207         sbi->alloc_blksz_shift = 0;
 208         while ((blocksize >>= 1) != 0)
 209                 sbi->alloc_blksz_shift++;
 210         blocksize = min(sbi->alloc_blksz, (u32)PAGE_SIZE);
 211
 212         /*
 213          * Align block size to block offset.
 214          */
 215         while (part_start & ((blocksize >> HFSPLUS_SECTOR_SHIFT) - 1))
 216                 blocksize >>= 1;
 217
 218         if (sb_set_blocksize(sb, blocksize) != blocksize) {
 219                 printk(KERN_ERR "hfs: unable to set blocksize to %u!\n",
 220                         blocksize);
 221                 goto out_free_backup_vhdr;
 222         }
 223
 224         sbi->blockoffset =
 225                 part_start >> (sb->s_blocksize_bits - HFSPLUS_SECTOR_SHIFT);
 226         sbi->part_start = part_start;
 227         sbi->sect_count = part_size;
 228         sbi->fs_shift = sbi->alloc_blksz_shift - sb->s_blocksize_bits;
 229         return 0;
 230
 231 out_free_backup_vhdr:
 232         kfree(sbi->s_backup_vhdr);
 233 out_free_vhdr:
 234         kfree(sbi->s_vhdr);
 235 out:
 236         return error;
 237 }