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fs/adfs: map: move map reading and validation to map.c 

Keep all the map code together in map.c, rather than having some in
super.c

Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Russell King 2019-12-09 11:08:28 +00:00 committed by Al Viro
parent 81916245ce
commit f75d398d6e
3 changed files with 100 additions and 98 deletions
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1
fs/adfs/adfs.h
View File

@ -146,6 +146,7 @@ int adfs_notify_change(struct dentry *dentry, struct iattr *attr);
/* map.c */ /* map.c */
int adfs_map_lookup(struct super_block *sb, u32 frag_id, unsigned int offset); int adfs_map_lookup(struct super_block *sb, u32 frag_id, unsigned int offset);
extern unsigned int adfs_map_free(struct super_block *sb); extern unsigned int adfs_map_free(struct super_block *sb);
struct adfs_discmap *adfs_read_map(struct super_block *sb, struct adfs_discrecord *dr);
/* Misc */ /* Misc */
__printf(3, 4) __printf(3, 4)

99
fs/adfs/map.c
View File

@ -4,6 +4,7 @@
* *
* Copyright (C) 1997-2002 Russell King * Copyright (C) 1997-2002 Russell King
*/ */
#include <linux/slab.h>
#include <asm/unaligned.h> #include <asm/unaligned.h>
#include "adfs.h" #include "adfs.h"
@ -280,3 +281,101 @@ bad_fragment:
frag_id, zone, asb->s_map_size); frag_id, zone, asb->s_map_size);
return 0; return 0;
} }
static unsigned char adfs_calczonecheck(struct super_block *sb, unsigned char *map)
{
unsigned int v0, v1, v2, v3;
int i;
v0 = v1 = v2 = v3 = 0;
for (i = sb->s_blocksize - 4; i; i -= 4) {
v0 += map[i] + (v3 >> 8);
v3 &= 0xff;
v1 += map[i + 1] + (v0 >> 8);
v0 &= 0xff;
v2 += map[i + 2] + (v1 >> 8);
v1 &= 0xff;
v3 += map[i + 3] + (v2 >> 8);
v2 &= 0xff;
}
v0 += v3 >> 8;
v1 += map[1] + (v0 >> 8);
v2 += map[2] + (v1 >> 8);
v3 += map[3] + (v2 >> 8);
return v0 ^ v1 ^ v2 ^ v3;
}
static int adfs_checkmap(struct super_block *sb, struct adfs_discmap *dm)
{
unsigned char crosscheck = 0, zonecheck = 1;
int i;
for (i = 0; i < ADFS_SB(sb)->s_map_size; i++) {
unsigned char *map;
map = dm[i].dm_bh->b_data;
if (adfs_calczonecheck(sb, map) != map[0]) {
adfs_error(sb, "zone %d fails zonecheck", i);
zonecheck = 0;
}
crosscheck ^= map[3];
}
if (crosscheck != 0xff)
adfs_error(sb, "crosscheck != 0xff");
return crosscheck == 0xff && zonecheck;
}
struct adfs_discmap *adfs_read_map(struct super_block *sb, struct adfs_discrecord *dr)
{
struct adfs_discmap *dm;
unsigned int map_addr, zone_size, nzones;
int i, zone;
struct adfs_sb_info *asb = ADFS_SB(sb);
nzones = asb->s_map_size;
zone_size = (8 << dr->log2secsize) - le16_to_cpu(dr->zone_spare);
map_addr = (nzones >> 1) * zone_size -
((nzones > 1) ? ADFS_DR_SIZE_BITS : 0);
map_addr = signed_asl(map_addr, asb->s_map2blk);
asb->s_ids_per_zone = zone_size / (asb->s_idlen + 1);
dm = kmalloc_array(nzones, sizeof(*dm), GFP_KERNEL);
if (dm == NULL) {
adfs_error(sb, "not enough memory");
return ERR_PTR(-ENOMEM);
}
for (zone = 0; zone < nzones; zone++, map_addr++) {
dm[zone].dm_startbit = 0;
dm[zone].dm_endbit = zone_size;
dm[zone].dm_startblk = zone * zone_size - ADFS_DR_SIZE_BITS;
dm[zone].dm_bh = sb_bread(sb, map_addr);
if (!dm[zone].dm_bh) {
adfs_error(sb, "unable to read map");
goto error_free;
}
}
/* adjust the limits for the first and last map zones */
i = zone - 1;
dm[0].dm_startblk = 0;
dm[0].dm_startbit = ADFS_DR_SIZE_BITS;
dm[i].dm_endbit = (adfs_disc_size(dr) >> dr->log2bpmb) +
(ADFS_DR_SIZE_BITS - i * zone_size);
if (adfs_checkmap(sb, dm))
return dm;
adfs_error(sb, "map corrupted");
error_free:
while (--zone >= 0)
brelse(dm[zone].dm_bh);
kfree(dm);
return ERR_PTR(-EIO);
}

98
fs/adfs/super.c
View File

@ -88,51 +88,6 @@ static int adfs_checkdiscrecord(struct adfs_discrecord *dr)
return 0; return 0;
} }
static unsigned char adfs_calczonecheck(struct super_block *sb, unsigned char *map)
{
unsigned int v0, v1, v2, v3;
int i;
v0 = v1 = v2 = v3 = 0;
for (i = sb->s_blocksize - 4; i; i -= 4) {
v0 += map[i] + (v3 >> 8);
v3 &= 0xff;
v1 += map[i + 1] + (v0 >> 8);
v0 &= 0xff;
v2 += map[i + 2] + (v1 >> 8);
v1 &= 0xff;
v3 += map[i + 3] + (v2 >> 8);
v2 &= 0xff;
}
v0 += v3 >> 8;
v1 += map[1] + (v0 >> 8);
v2 += map[2] + (v1 >> 8);
v3 += map[3] + (v2 >> 8);
return v0 ^ v1 ^ v2 ^ v3;
}
static int adfs_checkmap(struct super_block *sb, struct adfs_discmap *dm)
{
unsigned char crosscheck = 0, zonecheck = 1;
int i;
for (i = 0; i < ADFS_SB(sb)->s_map_size; i++) {
unsigned char *map;
map = dm[i].dm_bh->b_data;
if (adfs_calczonecheck(sb, map) != map[0]) {
adfs_error(sb, "zone %d fails zonecheck", i);
zonecheck = 0;
}
crosscheck ^= map[3];
}
if (crosscheck != 0xff)
adfs_error(sb, "crosscheck != 0xff");
return crosscheck == 0xff && zonecheck;
}
static void adfs_put_super(struct super_block *sb) static void adfs_put_super(struct super_block *sb)
{ {
int i; int i;
@ -322,59 +277,6 @@ static const struct super_operations adfs_sops = {
.show_options = adfs_show_options, .show_options = adfs_show_options,
}; };
static struct adfs_discmap *adfs_read_map(struct super_block *sb, struct adfs_discrecord *dr)
{
struct adfs_discmap *dm;
unsigned int map_addr, zone_size, nzones;
int i, zone;
struct adfs_sb_info *asb = ADFS_SB(sb);
nzones = asb->s_map_size;
zone_size = (8 << dr->log2secsize) - le16_to_cpu(dr->zone_spare);
map_addr = (nzones >> 1) * zone_size -
((nzones > 1) ? ADFS_DR_SIZE_BITS : 0);
map_addr = signed_asl(map_addr, asb->s_map2blk);
asb->s_ids_per_zone = zone_size / (asb->s_idlen + 1);
dm = kmalloc_array(nzones, sizeof(*dm), GFP_KERNEL);
if (dm == NULL) {
adfs_error(sb, "not enough memory");
return ERR_PTR(-ENOMEM);
}
for (zone = 0; zone < nzones; zone++, map_addr++) {
dm[zone].dm_startbit = 0;
dm[zone].dm_endbit = zone_size;
dm[zone].dm_startblk = zone * zone_size - ADFS_DR_SIZE_BITS;
dm[zone].dm_bh = sb_bread(sb, map_addr);
if (!dm[zone].dm_bh) {
adfs_error(sb, "unable to read map");
goto error_free;
}
}
/* adjust the limits for the first and last map zones */
i = zone - 1;
dm[0].dm_startblk = 0;
dm[0].dm_startbit = ADFS_DR_SIZE_BITS;
dm[i].dm_endbit = (adfs_disc_size(dr) >> dr->log2bpmb) +
(ADFS_DR_SIZE_BITS - i * zone_size);
if (adfs_checkmap(sb, dm))
return dm;
adfs_error(sb, "map corrupted");
error_free:
while (--zone >= 0)
brelse(dm[zone].dm_bh);
kfree(dm);
return ERR_PTR(-EIO);
}
static int adfs_fill_super(struct super_block *sb, void *data, int silent) static int adfs_fill_super(struct super_block *sb, void *data, int silent)
{ {
struct adfs_discrecord *dr; struct adfs_discrecord *dr;