Add the rt linux 4.1.3-rt3 as base

[kvmfornfv.git] / kernel / fs / hfsplus / part_tbl.c

diff --git a/kernel/fs/hfsplus/part_tbl.c b/kernel/fs/hfsplus/part_tbl.c
new file mode 100644 (file)
index 0000000..eb355d8
--- /dev/null
+++ b/kernel/fs/hfsplus/part_tbl.c
@@ -0,0 +1,157 @@
+/*
+ * linux/fs/hfsplus/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 <linux/slab.h>
+#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;
+
+static int hfs_parse_old_pmap(struct super_block *sb, struct old_pmap *pm,
+               sector_t *part_start, sector_t *part_size)
+{
+       struct hfsplus_sb_info *sbi = HFSPLUS_SB(sb);
+       int i;
+
+       for (i = 0; i < 42; i++) {
+               struct old_pmap_entry *p = &pm->pdEntry[i];
+
+               if (p->pdStart && p->pdSize &&
+                   p->pdFSID == cpu_to_be32(0x54465331)/*"TFS1"*/ &&
+                   (sbi->part < 0 || sbi->part == i)) {
+                       *part_start += be32_to_cpu(p->pdStart);
+                       *part_size = be32_to_cpu(p->pdSize);
+                       return 0;
+               }
+       }
+
+       return -ENOENT;
+}
+
+static int hfs_parse_new_pmap(struct super_block *sb, void *buf,
+               struct new_pmap *pm, sector_t *part_start, sector_t *part_size)
+{
+       struct hfsplus_sb_info *sbi = HFSPLUS_SB(sb);
+       int size = be32_to_cpu(pm->pmMapBlkCnt);
+       int buf_size = hfsplus_min_io_size(sb);
+       int res;
+       int i = 0;
+
+       do {
+               if (!memcmp(pm->pmPartType, "Apple_HFS", 9) &&
+                   (sbi->part < 0 || sbi->part == i)) {
+                       *part_start += be32_to_cpu(pm->pmPyPartStart);
+                       *part_size = be32_to_cpu(pm->pmPartBlkCnt);
+                       return 0;
+               }
+
+               if (++i >= size)
+                       return -ENOENT;
+
+               pm = (struct new_pmap *)((u8 *)pm + HFSPLUS_SECTOR_SIZE);
+               if ((u8 *)pm - (u8 *)buf >= buf_size) {
+                       res = hfsplus_submit_bio(sb,
+                                                *part_start + HFS_PMAP_BLK + i,
+                                                buf, (void **)&pm, READ);
+                       if (res)
+                               return res;
+               }
+       } while (pm->pmSig == cpu_to_be16(HFS_NEW_PMAP_MAGIC));
+
+       return -ENOENT;
+}
+
+/*
+ * Parse the partition map looking for the start and length of a
+ * HFS/HFS+ partition.
+ */
+int hfs_part_find(struct super_block *sb,
+               sector_t *part_start, sector_t *part_size)
+{
+       void *buf, *data;
+       int res;
+
+       buf = kmalloc(hfsplus_min_io_size(sb), GFP_KERNEL);
+       if (!buf)
+               return -ENOMEM;
+
+       res = hfsplus_submit_bio(sb, *part_start + HFS_PMAP_BLK,
+                                buf, &data, READ);
+       if (res)
+               goto out;
+
+       switch (be16_to_cpu(*((__be16 *)data))) {
+       case HFS_OLD_PMAP_MAGIC:
+               res = hfs_parse_old_pmap(sb, data, part_start, part_size);
+               break;
+       case HFS_NEW_PMAP_MAGIC:
+               res = hfs_parse_new_pmap(sb, buf, data, part_start, part_size);
+               break;
+       default:
+               res = -ENOENT;
+               break;
+       }
+out:
+       kfree(buf);
+       return res;
+}