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hfsplus: use raw bio access for partition tables 

Switch the hfsplus partition table reding for cdroms to use our bio
helpers.  Again we don't rely on any caching in the buffer_heads, and
this gets rid of the last buffer_head use in hfsplus.

Signed-off-by: Christoph Hellwig <hch@tuxera.com>
This commit is contained in:
Christoph Hellwig 2010-11-23 14:37:51 +01:00 committed by Christoph Hellwig
parent 52399b171d
commit 358f26d526
2 changed files with 76 additions and 75 deletions
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17
fs/hfsplus/hfsplus_fs.h
View File

@ -401,23 +401,6 @@ static inline struct hfsplus_inode_info *HFSPLUS_I(struct inode *inode)
return list_entry(inode, struct hfsplus_inode_info, vfs_inode);
}
#define sb_bread512(sb, sec, data) ({ \
struct buffer_head *__bh; \
sector_t __block; \
loff_t __start; \
int __offset; \
\
__start = (loff_t)(sec) << HFSPLUS_SECTOR_SHIFT;\
__block = __start >> (sb)->s_blocksize_bits; \
__offset = __start & ((sb)->s_blocksize - 1); \
__bh = sb_bread((sb), __block); \
if (likely(__bh != NULL)) \
data = (void *)(__bh->b_data + __offset);\
else \
data = NULL; \
__bh; \
})
/* time macros */
#define __hfsp_mt2ut(t) (be32_to_cpu(t) - 2082844800U)
#define __hfsp_ut2mt(t) (cpu_to_be32(t + 2082844800U))

134
fs/hfsplus/part_tbl.c
View File

@ -13,6 +13,7 @@
*
*/
#include <linux/slab.h>
#include "hfsplus_fs.h"
/* offsets to various blocks */
@ -65,70 +66,87 @@ struct old_pmap {
} 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)
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);
struct buffer_head *bh;
__be16 *data;
int i, size, res;
int i;
res = -ENOENT;
bh = sb_bread512(sb, *part_start + HFS_PMAP_BLK, data);
if (!bh)
return -EIO;
for (i = 0; i < 42; i++) {
struct old_pmap_entry *p = &pm->pdEntry[i];
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"*/ &&
(sbi->part < 0 || sbi->part == i)) {
*part_start += be32_to_cpu(p->pdStart);
*part_size = be32_to_cpu(p->pdSize);
res = 0;
}
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;
}
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) &&
(sbi->part < 0 || sbi->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 -ENOENT;
}
static int hfs_parse_new_pmap(struct super_block *sb, 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 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;
res = hfsplus_submit_bio(sb->s_bdev,
*part_start + HFS_PMAP_BLK + i,
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 *data;
int res;
data = kmalloc(HFSPLUS_SECTOR_SIZE, GFP_KERNEL);
if (!data)
return -ENOMEM;
res = hfsplus_submit_bio(sb->s_bdev, *part_start + HFS_PMAP_BLK,
data, READ);
if (res)
return res;
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, data, part_start, part_size);
break;
default:
res = -ENOENT;
break;
}
kfree(data);
return res;
}