/* *  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){	struct buffer_head *bh;	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); 	qbh->data = data = kmalloc(2048, GFP_NOFS);	if (!data) {		printk("HPFS: hpfs_map_4sectors: out of memory\n");		goto bail;	} 	qbh->bh[0] = bh = sb_bread(s, secno);	if (!bh)		goto bail0;	memcpy(data, bh->b_data, 512); 	qbh->bh[1] = bh = sb_bread(s, secno + 1);	if (!bh)		goto bail1;	memcpy(data + 512, bh->b_data, 512); 	qbh->bh[2] = bh = sb_bread(s, secno + 2);	if (!bh)		goto bail2;	memcpy(data + 2 * 512, bh->b_data, 512); 	qbh->bh[3] = bh = sb_bread(s, secno + 3);	if (!bh)		goto bail3;	memcpy(data + 3 * 512, bh->b_data, 512); 	return data;  bail3:	brelse(qbh->bh[2]); bail2:	brelse(qbh->bh[1]); bail1:	brelse(qbh->bh[0]); bail0:	kfree(data);	printk("HPFS: hpfs_map_4sectors: read error\n"); bail:	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;	} 	/*return hpfs_map_4sectors(s, secno, qbh, 0);*/	if (!(qbh->data = kmalloc(2048, GFP_NOFS))) {		printk("HPFS: hpfs_get_4sectors: out of memory\n");		return NULL;	}	if (!(hpfs_get_sector(s, secno, &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;	memcpy(qbh->data, qbh->bh[0]->b_data, 512);	memcpy(qbh->data + 512, qbh->bh[1]->b_data, 512);	memcpy(qbh->data + 2*512, qbh->bh[2]->b_data, 512);	memcpy(qbh->data + 3*512, qbh->bh[3]->b_data, 512);	return qbh->data; 	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){	brelse(qbh->bh[3]);	brelse(qbh->bh[2]);	brelse(qbh->bh[1]);	brelse(qbh->bh[0]);	kfree(qbh->data);}	 void hpfs_mark_4buffers_dirty(struct quad_buffer_head *qbh){	memcpy(qbh->bh[0]->b_data, qbh->data, 512);	memcpy(qbh->bh[1]->b_data, qbh->data + 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]);}