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author | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 15:20:36 -0700 |
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committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 15:20:36 -0700 |
commit | 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch) | |
tree | 0bba044c4ce775e45a88a51686b5d9f90697ea9d /fs/hfsplus/part_tbl.c | |
download | talos-op-linux-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.tar.gz talos-op-linux-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.zip |
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Diffstat (limited to 'fs/hfsplus/part_tbl.c')
-rw-r--r-- | fs/hfsplus/part_tbl.c | 133 |
1 files changed, 133 insertions, 0 deletions
diff --git a/fs/hfsplus/part_tbl.c b/fs/hfsplus/part_tbl.c new file mode 100644 index 000000000000..ae783066fc3a --- /dev/null +++ b/fs/hfsplus/part_tbl.c @@ -0,0 +1,133 @@ +/* + * linux/fs/hfs/part_tbl.c + * + * Copyright (C) 1996-1997 Paul H. Hargrove + * This file may be distributed under the terms of the GNU General Public License. + * + * Original code to handle the new style Mac partition table based on + * a patch contributed by Holger Schemel (aeglos@valinor.owl.de). + * + * In function preconditions the term "valid" applied to a pointer to + * a structure means that the pointer is non-NULL and the structure it + * points to has all fields initialized to consistent values. + * + */ + +#include "hfsplus_fs.h" + +/* offsets to various blocks */ +#define HFS_DD_BLK 0 /* Driver Descriptor block */ +#define HFS_PMAP_BLK 1 /* First block of partition map */ +#define HFS_MDB_BLK 2 /* Block (w/i partition) of MDB */ + +/* magic numbers for various disk blocks */ +#define HFS_DRVR_DESC_MAGIC 0x4552 /* "ER": driver descriptor map */ +#define HFS_OLD_PMAP_MAGIC 0x5453 /* "TS": old-type partition map */ +#define HFS_NEW_PMAP_MAGIC 0x504D /* "PM": new-type partition map */ +#define HFS_SUPER_MAGIC 0x4244 /* "BD": HFS MDB (super block) */ +#define HFS_MFS_SUPER_MAGIC 0xD2D7 /* MFS MDB (super block) */ + +/* + * The new style Mac partition map + * + * For each partition on the media there is a physical block (512-byte + * block) containing one of these structures. These blocks are + * contiguous starting at block 1. + */ +struct new_pmap { + __be16 pmSig; /* signature */ + __be16 reSigPad; /* padding */ + __be32 pmMapBlkCnt; /* partition blocks count */ + __be32 pmPyPartStart; /* physical block start of partition */ + __be32 pmPartBlkCnt; /* physical block count of partition */ + u8 pmPartName[32]; /* (null terminated?) string + giving the name of this + partition */ + u8 pmPartType[32]; /* (null terminated?) string + giving the type of this + partition */ + /* a bunch more stuff we don't need */ +} __packed; + +/* + * The old style Mac partition map + * + * The partition map consists for a 2-byte signature followed by an + * array of these structures. The map is terminated with an all-zero + * one of these. + */ +struct old_pmap { + __be16 pdSig; /* Signature bytes */ + struct old_pmap_entry { + __be32 pdStart; + __be32 pdSize; + __be32 pdFSID; + } pdEntry[42]; +} __packed; + +/* + * hfs_part_find() + * + * Parse the partition map looking for the + * start and length of the 'part'th HFS partition. + */ +int hfs_part_find(struct super_block *sb, + sector_t *part_start, sector_t *part_size) +{ + struct buffer_head *bh; + __be16 *data; + int i, size, res; + + res = -ENOENT; + bh = sb_bread512(sb, *part_start + HFS_PMAP_BLK, data); + if (!bh) + return -EIO; + + switch (be16_to_cpu(*data)) { + case HFS_OLD_PMAP_MAGIC: + { + struct old_pmap *pm; + struct old_pmap_entry *p; + + pm = (struct old_pmap *)bh->b_data; + p = pm->pdEntry; + size = 42; + for (i = 0; i < size; p++, i++) { + if (p->pdStart && p->pdSize && + p->pdFSID == cpu_to_be32(0x54465331)/*"TFS1"*/ && + (HFSPLUS_SB(sb).part < 0 || HFSPLUS_SB(sb).part == i)) { + *part_start += be32_to_cpu(p->pdStart); + *part_size = be32_to_cpu(p->pdSize); + res = 0; + } + } + break; + } + case HFS_NEW_PMAP_MAGIC: + { + struct new_pmap *pm; + + pm = (struct new_pmap *)bh->b_data; + size = be32_to_cpu(pm->pmMapBlkCnt); + for (i = 0; i < size;) { + if (!memcmp(pm->pmPartType,"Apple_HFS", 9) && + (HFSPLUS_SB(sb).part < 0 || HFSPLUS_SB(sb).part == i)) { + *part_start += be32_to_cpu(pm->pmPyPartStart); + *part_size = be32_to_cpu(pm->pmPartBlkCnt); + res = 0; + break; + } + brelse(bh); + bh = sb_bread512(sb, *part_start + HFS_PMAP_BLK + ++i, pm); + if (!bh) + return -EIO; + if (pm->pmSig != cpu_to_be16(HFS_NEW_PMAP_MAGIC)) + break; + } + break; + } + } + brelse(bh); + + return res; +} |