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