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/*
* 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"
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;
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, secno);
if (bh != NULL)
return bh->b_data;
else {
printk("HPFS: hpfs_map_sector: read error\n");
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, secno)) != NULL) {
if (!buffer_uptodate(bh)) wait_on_buffer(bh);
set_buffer_uptodate(bh);
return bh->b_data;
} else {
printk("HPFS: hpfs_get_sector: getblk failed\n");
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) {
printk("HPFS: hpfs_map_4sectors: unaligned read\n");
return NULL;
}
hpfs_prefetch_sectors(s, secno, 4 + ahead);
if (!(qbh->bh[0] = sb_bread(s, secno + 0))) goto bail0;
if (!(qbh->bh[1] = sb_bread(s, secno + 1))) goto bail1;
if (!(qbh->bh[2] = sb_bread(s, secno + 2))) goto bail2;
if (!(qbh->bh[3] = sb_bread(s, secno + 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;
}
qbh->data = data = kmalloc(2048, GFP_NOFS);
if (!data) {
printk("HPFS: hpfs_map_4sectors: out of memory\n");
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) {
printk("HPFS: hpfs_get_4sectors: unaligned read\n");
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))) {
printk("HPFS: hpfs_get_4sectors: out of memory\n");
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]);
}
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