2 * linux/fs/hfsplus/part_tbl.c
4 * Copyright (C) 1996-1997 Paul H. Hargrove
5 * This file may be distributed under the terms of the GNU General Public License.
7 * Original code to handle the new style Mac partition table based on
8 * a patch contributed by Holger Schemel (aeglos@valinor.owl.de).
10 * In function preconditions the term "valid" applied to a pointer to
11 * a structure means that the pointer is non-NULL and the structure it
12 * points to has all fields initialized to consistent values.
16 #include "hfsplus_fs.h"
18 /* offsets to various blocks */
19 #define HFS_DD_BLK 0 /* Driver Descriptor block */
20 #define HFS_PMAP_BLK 1 /* First block of partition map */
21 #define HFS_MDB_BLK 2 /* Block (w/i partition) of MDB */
23 /* magic numbers for various disk blocks */
24 #define HFS_DRVR_DESC_MAGIC 0x4552 /* "ER": driver descriptor map */
25 #define HFS_OLD_PMAP_MAGIC 0x5453 /* "TS": old-type partition map */
26 #define HFS_NEW_PMAP_MAGIC 0x504D /* "PM": new-type partition map */
27 #define HFS_SUPER_MAGIC 0x4244 /* "BD": HFS MDB (super block) */
28 #define HFS_MFS_SUPER_MAGIC 0xD2D7 /* MFS MDB (super block) */
31 * The new style Mac partition map
33 * For each partition on the media there is a physical block (512-byte
34 * block) containing one of these structures. These blocks are
35 * contiguous starting at block 1.
38 __be16 pmSig
; /* signature */
39 __be16 reSigPad
; /* padding */
40 __be32 pmMapBlkCnt
; /* partition blocks count */
41 __be32 pmPyPartStart
; /* physical block start of partition */
42 __be32 pmPartBlkCnt
; /* physical block count of partition */
43 u8 pmPartName
[32]; /* (null terminated?) string
44 giving the name of this
46 u8 pmPartType
[32]; /* (null terminated?) string
47 giving the type of this
49 /* a bunch more stuff we don't need */
53 * The old style Mac partition map
55 * The partition map consists for a 2-byte signature followed by an
56 * array of these structures. The map is terminated with an all-zero
60 __be16 pdSig
; /* Signature bytes */
61 struct old_pmap_entry
{
71 * Parse the partition map looking for the
72 * start and length of the 'part'th HFS partition.
74 int hfs_part_find(struct super_block
*sb
,
75 sector_t
*part_start
, sector_t
*part_size
)
77 struct buffer_head
*bh
;
82 bh
= sb_bread512(sb
, *part_start
+ HFS_PMAP_BLK
, data
);
86 switch (be16_to_cpu(*data
)) {
87 case HFS_OLD_PMAP_MAGIC
:
90 struct old_pmap_entry
*p
;
92 pm
= (struct old_pmap
*)bh
->b_data
;
95 for (i
= 0; i
< size
; p
++, i
++) {
96 if (p
->pdStart
&& p
->pdSize
&&
97 p
->pdFSID
== cpu_to_be32(0x54465331)/*"TFS1"*/ &&
98 (HFSPLUS_SB(sb
).part
< 0 || HFSPLUS_SB(sb
).part
== i
)) {
99 *part_start
+= be32_to_cpu(p
->pdStart
);
100 *part_size
= be32_to_cpu(p
->pdSize
);
106 case HFS_NEW_PMAP_MAGIC
:
110 pm
= (struct new_pmap
*)bh
->b_data
;
111 size
= be32_to_cpu(pm
->pmMapBlkCnt
);
112 for (i
= 0; i
< size
;) {
113 if (!memcmp(pm
->pmPartType
,"Apple_HFS", 9) &&
114 (HFSPLUS_SB(sb
).part
< 0 || HFSPLUS_SB(sb
).part
== i
)) {
115 *part_start
+= be32_to_cpu(pm
->pmPyPartStart
);
116 *part_size
= be32_to_cpu(pm
->pmPartBlkCnt
);
121 bh
= sb_bread512(sb
, *part_start
+ HFS_PMAP_BLK
+ ++i
, pm
);
124 if (pm
->pmSig
!= cpu_to_be16(HFS_NEW_PMAP_MAGIC
))
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