[linux-2.6-block.git] / fs / hpfs / buffer.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"

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 {
		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, 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 (!(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) {
		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]);
}
Commit	Line	Data
1da177e4 LT	1	/*
	2	* linux/fs/hpfs/buffer.c
	3	*
	4	* Mikulas Patocka (mikulas@artax.karlin.mff.cuni.cz), 1998-1999
	5	*
	6	* general buffer i/o
	7	*/
e8edc6e0	8	#include <linux/sched.h>
5a0e3ad6	9	#include <linux/slab.h>
275f495d	10	#include <linux/blkdev.h>
1da177e4 LT	11	#include "hpfs_fn.h"
1da177e4 LT	12
275f495d MP	13	void hpfs_prefetch_sectors(struct super_block *s, unsigned secno, int n)
	14	{
	15	struct buffer_head *bh;
	16	struct blk_plug plug;
	17
	18	if (n <= 0 \|\| unlikely(secno >= hpfs_sb(s)->sb_fs_size))
	19	return;
	20
	21	bh = sb_find_get_block(s, secno);
	22	if (bh) {
	23	if (buffer_uptodate(bh)) {
	24	brelse(bh);
	25	return;
	26	}
	27	brelse(bh);
	28	};
	29
	30	blk_start_plug(&plug);
	31	while (n > 0) {
	32	if (unlikely(secno >= hpfs_sb(s)->sb_fs_size))
	33	break;
	34	sb_breadahead(s, secno);
	35	secno++;
	36	n--;
	37	}
	38	blk_finish_plug(&plug);
	39	}
	40
1da177e4 LT	41	/* Map a sector into a buffer and return pointers to it and to the buffer. */
	42
	43	void hpfs_map_sector(struct super_block s, unsigned secno, struct buffer_head **bhp,
	44	int ahead)
	45	{
	46	struct buffer_head *bh;
	47
7dd29d8d MP	48	hpfs_lock_assert(s);
7dd29d8d MP	49
275f495d MP	50	hpfs_prefetch_sectors(s, secno, ahead);
275f495d MP	51
1da177e4 LT	52	cond_resched();
	53
	54	*bhp = bh = sb_bread(s, secno);
	55	if (bh != NULL)
	56	return bh->b_data;
	57	else {
a19189e5	58	pr_err("%s(): read error\n", __func__);
1da177e4 LT	59	return NULL;
	60	}
	61	}
	62
	63	/* Like hpfs_map_sector but don't read anything */
	64
	65	void hpfs_get_sector(struct super_block s, unsigned secno, struct buffer_head **bhp)
	66	{
	67	struct buffer_head *bh;
	68	/return hpfs_map_sector(s, secno, bhp, 0);/
	69
7dd29d8d MP	70	hpfs_lock_assert(s);
7dd29d8d MP	71
1da177e4 LT	72	cond_resched();
	73
	74	if ((*bhp = bh = sb_getblk(s, secno)) != NULL) {
	75	if (!buffer_uptodate(bh)) wait_on_buffer(bh);
	76	set_buffer_uptodate(bh);
	77	return bh->b_data;
	78	} else {
a19189e5	79	pr_err("%s(): getblk failed\n", __func__);
1da177e4 LT	80	return NULL;
	81	}
	82	}
	83
	84	/* Map 4 sectors into a 4buffer and return pointers to it and to the buffer. */
	85
	86	void hpfs_map_4sectors(struct super_block s, unsigned secno, struct quad_buffer_head *qbh,
	87	int ahead)
	88	{
1da177e4 LT	89	char *data;
1da177e4 LT	90
7dd29d8d MP	91	hpfs_lock_assert(s);
7dd29d8d MP	92
1da177e4 LT	93	cond_resched();
	94
	95	if (secno & 3) {
a19189e5	96	pr_err("%s(): unaligned read\n", __func__);
1da177e4 LT	97	return NULL;
	98	}
	99
275f495d MP	100	hpfs_prefetch_sectors(s, secno, 4 + ahead);
275f495d MP	101
1c0b8a7a MP	102	if (!(qbh->bh[0] = sb_bread(s, secno + 0))) goto bail0;
	103	if (!(qbh->bh[1] = sb_bread(s, secno + 1))) goto bail1;
	104	if (!(qbh->bh[2] = sb_bread(s, secno + 2))) goto bail2;
	105	if (!(qbh->bh[3] = sb_bread(s, secno + 3))) goto bail3;
	106
	107	if (likely(qbh->bh[1]->b_data == qbh->bh[0]->b_data + 1 * 512) &&
	108	likely(qbh->bh[2]->b_data == qbh->bh[0]->b_data + 2 * 512) &&
	109	likely(qbh->bh[3]->b_data == qbh->bh[0]->b_data + 3 * 512)) {
	110	return qbh->data = qbh->bh[0]->b_data;
	111	}
	112
f52720ca	113	qbh->data = data = kmalloc(2048, GFP_NOFS);
1da177e4	114	if (!data) {
a19189e5	115	pr_err("%s(): out of memory\n", __func__);
1c0b8a7a	116	goto bail4;
1da177e4 LT	117	}
1da177e4 LT	118
1c0b8a7a MP	119	memcpy(data + 0 * 512, qbh->bh[0]->b_data, 512);
	120	memcpy(data + 1 * 512, qbh->bh[1]->b_data, 512);
	121	memcpy(data + 2 * 512, qbh->bh[2]->b_data, 512);
	122	memcpy(data + 3 * 512, qbh->bh[3]->b_data, 512);
1da177e4 LT	123
	124	return data;
	125
1c0b8a7a MP	126	bail4:
1c0b8a7a MP	127	brelse(qbh->bh[3]);
1da177e4 LT	128	bail3:
	129	brelse(qbh->bh[2]);
	130	bail2:
	131	brelse(qbh->bh[1]);
	132	bail1:
	133	brelse(qbh->bh[0]);
	134	bail0:
1da177e4 LT	135	return NULL;
	136	}
	137
	138	/* Don't read sectors */
	139
	140	void hpfs_get_4sectors(struct super_block s, unsigned secno,
	141	struct quad_buffer_head *qbh)
	142	{
	143	cond_resched();
	144
7dd29d8d MP	145	hpfs_lock_assert(s);
7dd29d8d MP	146
1da177e4	147	if (secno & 3) {
a19189e5	148	pr_err("%s(): unaligned read\n", __func__);
1da177e4 LT	149	return NULL;
	150	}
	151
1c0b8a7a MP	152	if (!hpfs_get_sector(s, secno + 0, &qbh->bh[0])) goto bail0;
	153	if (!hpfs_get_sector(s, secno + 1, &qbh->bh[1])) goto bail1;
	154	if (!hpfs_get_sector(s, secno + 2, &qbh->bh[2])) goto bail2;
	155	if (!hpfs_get_sector(s, secno + 3, &qbh->bh[3])) goto bail3;
	156
	157	if (likely(qbh->bh[1]->b_data == qbh->bh[0]->b_data + 1 * 512) &&
	158	likely(qbh->bh[2]->b_data == qbh->bh[0]->b_data + 2 * 512) &&
	159	likely(qbh->bh[3]->b_data == qbh->bh[0]->b_data + 3 * 512)) {
	160	return qbh->data = qbh->bh[0]->b_data;
	161	}
	162
1da177e4	163	if (!(qbh->data = kmalloc(2048, GFP_NOFS))) {
a19189e5	164	pr_err("%s(): out of memory\n", __func__);
1c0b8a7a	165	goto bail4;
1da177e4	166	}
1da177e4 LT	167	return qbh->data;
1da177e4 LT	168
1c0b8a7a MP	169	bail4:
	170	brelse(qbh->bh[3]);
	171	bail3:
	172	brelse(qbh->bh[2]);
	173	bail2:
	174	brelse(qbh->bh[1]);
	175	bail1:
	176	brelse(qbh->bh[0]);
	177	bail0:
1da177e4 LT	178	return NULL;
	179	}
	180
	181
	182	void hpfs_brelse4(struct quad_buffer_head *qbh)
	183	{
1c0b8a7a MP	184	if (unlikely(qbh->data != qbh->bh[0]->b_data))
1c0b8a7a MP	185	kfree(qbh->data);
1da177e4	186	brelse(qbh->bh[0]);
1c0b8a7a MP	187	brelse(qbh->bh[1]);
	188	brelse(qbh->bh[2]);
	189	brelse(qbh->bh[3]);
1da177e4 LT	190	}
	191
	192	void hpfs_mark_4buffers_dirty(struct quad_buffer_head *qbh)
	193	{
1c0b8a7a MP	194	if (unlikely(qbh->data != qbh->bh[0]->b_data)) {
	195	memcpy(qbh->bh[0]->b_data, qbh->data + 0 * 512, 512);
	196	memcpy(qbh->bh[1]->b_data, qbh->data + 1 * 512, 512);
	197	memcpy(qbh->bh[2]->b_data, qbh->data + 2 * 512, 512);
	198	memcpy(qbh->bh[3]->b_data, qbh->data + 3 * 512, 512);
	199	}
1da177e4 LT	200	mark_buffer_dirty(qbh->bh[0]);
	201	mark_buffer_dirty(qbh->bh[1]);
	202	mark_buffer_dirty(qbh->bh[2]);
	203	mark_buffer_dirty(qbh->bh[3]);
	204	}