linux/fs/hpfs/buffer.c
Mikulas Patocka a64eefaac1 hpfs: support hotfixes
When the OS/2 driver hits a disk write error, it writes the sector to
another location and adds the sector mapping to the hotfix map.

This patch makes the hpfs driver understand the hotfix map and remap
accesses accoring to it.

Signed-off-by: Mikulas Patocka <mikulas@twibright.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-09-03 11:55:30 -07:00

232 lines
5.3 KiB
C

/*
* linux/fs/hpfs/buffer.c
*
* Mikulas Patocka (mikulas@artax.karlin.mff.cuni.cz), 1998-1999
*
* general buffer i/o
*/
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/blkdev.h>
#include "hpfs_fn.h"
secno hpfs_search_hotfix_map(struct super_block *s, secno sec)
{
unsigned i;
struct hpfs_sb_info *sbi = hpfs_sb(s);
for (i = 0; unlikely(i < sbi->n_hotfixes); i++) {
if (sbi->hotfix_from[i] == sec) {
return sbi->hotfix_to[i];
}
}
return sec;
}
unsigned hpfs_search_hotfix_map_for_range(struct super_block *s, secno sec, unsigned n)
{
unsigned i;
struct hpfs_sb_info *sbi = hpfs_sb(s);
for (i = 0; unlikely(i < sbi->n_hotfixes); i++) {
if (sbi->hotfix_from[i] >= sec && sbi->hotfix_from[i] < sec + n) {
n = sbi->hotfix_from[i] - sec;
}
}
return n;
}
void hpfs_prefetch_sectors(struct super_block *s, unsigned secno, int n)
{
struct buffer_head *bh;
struct blk_plug plug;
if (n <= 0 || unlikely(secno >= hpfs_sb(s)->sb_fs_size))
return;
if (unlikely(hpfs_search_hotfix_map_for_range(s, secno, n) != n))
return;
bh = sb_find_get_block(s, secno);
if (bh) {
if (buffer_uptodate(bh)) {
brelse(bh);
return;
}
brelse(bh);
};
blk_start_plug(&plug);
while (n > 0) {
if (unlikely(secno >= hpfs_sb(s)->sb_fs_size))
break;
sb_breadahead(s, secno);
secno++;
n--;
}
blk_finish_plug(&plug);
}
/* Map a sector into a buffer and return pointers to it and to the buffer. */
void *hpfs_map_sector(struct super_block *s, unsigned secno, struct buffer_head **bhp,
int ahead)
{
struct buffer_head *bh;
hpfs_lock_assert(s);
hpfs_prefetch_sectors(s, secno, ahead);
cond_resched();
*bhp = bh = sb_bread(s, hpfs_search_hotfix_map(s, secno));
if (bh != NULL)
return bh->b_data;
else {
pr_err("%s(): read error\n", __func__);
return NULL;
}
}
/* Like hpfs_map_sector but don't read anything */
void *hpfs_get_sector(struct super_block *s, unsigned secno, struct buffer_head **bhp)
{
struct buffer_head *bh;
/*return hpfs_map_sector(s, secno, bhp, 0);*/
hpfs_lock_assert(s);
cond_resched();
if ((*bhp = bh = sb_getblk(s, hpfs_search_hotfix_map(s, secno))) != NULL) {
if (!buffer_uptodate(bh)) wait_on_buffer(bh);
set_buffer_uptodate(bh);
return bh->b_data;
} else {
pr_err("%s(): getblk failed\n", __func__);
return NULL;
}
}
/* Map 4 sectors into a 4buffer and return pointers to it and to the buffer. */
void *hpfs_map_4sectors(struct super_block *s, unsigned secno, struct quad_buffer_head *qbh,
int ahead)
{
char *data;
hpfs_lock_assert(s);
cond_resched();
if (secno & 3) {
pr_err("%s(): unaligned read\n", __func__);
return NULL;
}
hpfs_prefetch_sectors(s, secno, 4 + ahead);
if (!hpfs_map_sector(s, secno + 0, &qbh->bh[0], 0)) goto bail0;
if (!hpfs_map_sector(s, secno + 1, &qbh->bh[1], 0)) goto bail1;
if (!hpfs_map_sector(s, secno + 2, &qbh->bh[2], 0)) goto bail2;
if (!hpfs_map_sector(s, secno + 3, &qbh->bh[3], 0)) goto bail3;
if (likely(qbh->bh[1]->b_data == qbh->bh[0]->b_data + 1 * 512) &&
likely(qbh->bh[2]->b_data == qbh->bh[0]->b_data + 2 * 512) &&
likely(qbh->bh[3]->b_data == qbh->bh[0]->b_data + 3 * 512)) {
return qbh->data = qbh->bh[0]->b_data;
}
qbh->data = data = kmalloc(2048, GFP_NOFS);
if (!data) {
pr_err("%s(): out of memory\n", __func__);
goto bail4;
}
memcpy(data + 0 * 512, qbh->bh[0]->b_data, 512);
memcpy(data + 1 * 512, qbh->bh[1]->b_data, 512);
memcpy(data + 2 * 512, qbh->bh[2]->b_data, 512);
memcpy(data + 3 * 512, qbh->bh[3]->b_data, 512);
return data;
bail4:
brelse(qbh->bh[3]);
bail3:
brelse(qbh->bh[2]);
bail2:
brelse(qbh->bh[1]);
bail1:
brelse(qbh->bh[0]);
bail0:
return NULL;
}
/* Don't read sectors */
void *hpfs_get_4sectors(struct super_block *s, unsigned secno,
struct quad_buffer_head *qbh)
{
cond_resched();
hpfs_lock_assert(s);
if (secno & 3) {
pr_err("%s(): unaligned read\n", __func__);
return NULL;
}
if (!hpfs_get_sector(s, secno + 0, &qbh->bh[0])) goto bail0;
if (!hpfs_get_sector(s, secno + 1, &qbh->bh[1])) goto bail1;
if (!hpfs_get_sector(s, secno + 2, &qbh->bh[2])) goto bail2;
if (!hpfs_get_sector(s, secno + 3, &qbh->bh[3])) goto bail3;
if (likely(qbh->bh[1]->b_data == qbh->bh[0]->b_data + 1 * 512) &&
likely(qbh->bh[2]->b_data == qbh->bh[0]->b_data + 2 * 512) &&
likely(qbh->bh[3]->b_data == qbh->bh[0]->b_data + 3 * 512)) {
return qbh->data = qbh->bh[0]->b_data;
}
if (!(qbh->data = kmalloc(2048, GFP_NOFS))) {
pr_err("%s(): out of memory\n", __func__);
goto bail4;
}
return qbh->data;
bail4:
brelse(qbh->bh[3]);
bail3:
brelse(qbh->bh[2]);
bail2:
brelse(qbh->bh[1]);
bail1:
brelse(qbh->bh[0]);
bail0:
return NULL;
}
void hpfs_brelse4(struct quad_buffer_head *qbh)
{
if (unlikely(qbh->data != qbh->bh[0]->b_data))
kfree(qbh->data);
brelse(qbh->bh[0]);
brelse(qbh->bh[1]);
brelse(qbh->bh[2]);
brelse(qbh->bh[3]);
}
void hpfs_mark_4buffers_dirty(struct quad_buffer_head *qbh)
{
if (unlikely(qbh->data != qbh->bh[0]->b_data)) {
memcpy(qbh->bh[0]->b_data, qbh->data + 0 * 512, 512);
memcpy(qbh->bh[1]->b_data, qbh->data + 1 * 512, 512);
memcpy(qbh->bh[2]->b_data, qbh->data + 2 * 512, 512);
memcpy(qbh->bh[3]->b_data, qbh->data + 3 * 512, 512);
}
mark_buffer_dirty(qbh->bh[0]);
mark_buffer_dirty(qbh->bh[1]);
mark_buffer_dirty(qbh->bh[2]);
mark_buffer_dirty(qbh->bh[3]);
}