[linux.git] / fs / iomap / seek.c

// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (C) 2017 Red Hat, Inc.
 * Copyright (c) 2018-2021 Christoph Hellwig.
 */
#include <linux/module.h>
#include <linux/compiler.h>
#include <linux/fs.h>
#include <linux/iomap.h>
#include <linux/pagemap.h>
#include <linux/pagevec.h>

static loff_t iomap_seek_hole_iter(const struct iomap_iter *iter,
		loff_t *hole_pos)
{
	loff_t length = iomap_length(iter);

	switch (iter->iomap.type) {
	case IOMAP_UNWRITTEN:
		*hole_pos = mapping_seek_hole_data(iter->inode->i_mapping,
				iter->pos, iter->pos + length, SEEK_HOLE);
		if (*hole_pos == iter->pos + length)
			return length;
		return 0;
	case IOMAP_HOLE:
		*hole_pos = iter->pos;
		return 0;
	default:
		return length;
	}
}

loff_t
iomap_seek_hole(struct inode *inode, loff_t pos, const struct iomap_ops *ops)
{
	loff_t size = i_size_read(inode);
	struct iomap_iter iter = {
		.inode	= inode,
		.pos	= pos,
		.flags	= IOMAP_REPORT,
	};
	int ret;

	/* Nothing to be found before or beyond the end of the file. */
	if (pos < 0 || pos >= size)
		return -ENXIO;

	iter.len = size - pos;
	while ((ret = iomap_iter(&iter, ops)) > 0)
		iter.processed = iomap_seek_hole_iter(&iter, &pos);
	if (ret < 0)
		return ret;
	if (iter.len) /* found hole before EOF */
		return pos;
	return size;
}
EXPORT_SYMBOL_GPL(iomap_seek_hole);

static loff_t iomap_seek_data_iter(const struct iomap_iter *iter,
		loff_t *hole_pos)
{
	loff_t length = iomap_length(iter);

	switch (iter->iomap.type) {
	case IOMAP_HOLE:
		return length;
	case IOMAP_UNWRITTEN:
		*hole_pos = mapping_seek_hole_data(iter->inode->i_mapping,
				iter->pos, iter->pos + length, SEEK_DATA);
		if (*hole_pos < 0)
			return length;
		return 0;
	default:
		*hole_pos = iter->pos;
		return 0;
	}
}

loff_t
iomap_seek_data(struct inode *inode, loff_t pos, const struct iomap_ops *ops)
{
	loff_t size = i_size_read(inode);
	struct iomap_iter iter = {
		.inode	= inode,
		.pos	= pos,
		.flags	= IOMAP_REPORT,
	};
	int ret;

	/* Nothing to be found before or beyond the end of the file. */
	if (pos < 0 || pos >= size)
		return -ENXIO;

	iter.len = size - pos;
	while ((ret = iomap_iter(&iter, ops)) > 0)
		iter.processed = iomap_seek_data_iter(&iter, &pos);
	if (ret < 0)
		return ret;
	if (iter.len) /* found data before EOF */
		return pos;
	/* We've reached the end of the file without finding data */
	return -ENXIO;
}
EXPORT_SYMBOL_GPL(iomap_seek_data);
Commit	Line	Data
56a17898 DW	1	// SPDX-License-Identifier: GPL-2.0
	2	/*
	3	* Copyright (C) 2017 Red Hat, Inc.
40670d18	4	* Copyright (c) 2018-2021 Christoph Hellwig.
56a17898 DW	5	*/
	6	#include <linux/module.h>
	7	#include <linux/compiler.h>
	8	#include <linux/fs.h>
	9	#include <linux/iomap.h>
	10	#include <linux/pagemap.h>
	11	#include <linux/pagevec.h>
	12
40670d18 CH	13	static loff_t iomap_seek_hole_iter(const struct iomap_iter *iter,
40670d18 CH	14	loff_t *hole_pos)
56a17898	15	{
40670d18	16	loff_t length = iomap_length(iter);
54fa39ac	17
40670d18	18	switch (iter->iomap.type) {
56a17898	19	case IOMAP_UNWRITTEN:
40670d18 CH	20	*hole_pos = mapping_seek_hole_data(iter->inode->i_mapping,
	21	iter->pos, iter->pos + length, SEEK_HOLE);
	22	if (*hole_pos == iter->pos + length)
56a17898	23	return length;
40670d18	24	return 0;
56a17898	25	case IOMAP_HOLE:
40670d18	26	*hole_pos = iter->pos;
56a17898 DW	27	return 0;
	28	default:
	29	return length;
	30	}
	31	}
	32
	33	loff_t
40670d18	34	iomap_seek_hole(struct inode inode, loff_t pos, const struct iomap_ops ops)
56a17898 DW	35	{
56a17898 DW	36	loff_t size = i_size_read(inode);
40670d18 CH	37	struct iomap_iter iter = {
	38	.inode = inode,
	39	.pos = pos,
	40	.flags = IOMAP_REPORT,
	41	};
	42	int ret;
56a17898 DW	43
56a17898 DW	44	/* Nothing to be found before or beyond the end of the file. */
40670d18	45	if (pos < 0 \|\| pos >= size)
56a17898 DW	46	return -ENXIO;
56a17898 DW	47
40670d18 CH	48	iter.len = size - pos;
	49	while ((ret = iomap_iter(&iter, ops)) > 0)
	50	iter.processed = iomap_seek_hole_iter(&iter, &pos);
	51	if (ret < 0)
	52	return ret;
	53	if (iter.len) /* found hole before EOF */
	54	return pos;
	55	return size;
56a17898 DW	56	}
	57	EXPORT_SYMBOL_GPL(iomap_seek_hole);
	58
c4740bf1 CH	59	static loff_t iomap_seek_data_iter(const struct iomap_iter *iter,
c4740bf1 CH	60	loff_t *hole_pos)
56a17898	61	{
c4740bf1	62	loff_t length = iomap_length(iter);
54fa39ac	63
c4740bf1	64	switch (iter->iomap.type) {
56a17898 DW	65	case IOMAP_HOLE:
	66	return length;
	67	case IOMAP_UNWRITTEN:
c4740bf1 CH	68	*hole_pos = mapping_seek_hole_data(iter->inode->i_mapping,
	69	iter->pos, iter->pos + length, SEEK_DATA);
	70	if (*hole_pos < 0)
56a17898	71	return length;
c4740bf1	72	return 0;
56a17898	73	default:
c4740bf1	74	*hole_pos = iter->pos;
56a17898 DW	75	return 0;
	76	}
	77	}
	78
	79	loff_t
c4740bf1	80	iomap_seek_data(struct inode inode, loff_t pos, const struct iomap_ops ops)
56a17898 DW	81	{
56a17898 DW	82	loff_t size = i_size_read(inode);
c4740bf1 CH	83	struct iomap_iter iter = {
	84	.inode = inode,
	85	.pos = pos,
	86	.flags = IOMAP_REPORT,
	87	};
	88	int ret;
56a17898 DW	89
56a17898 DW	90	/* Nothing to be found before or beyond the end of the file. */
c4740bf1	91	if (pos < 0 \|\| pos >= size)
56a17898 DW	92	return -ENXIO;
56a17898 DW	93
c4740bf1 CH	94	iter.len = size - pos;
	95	while ((ret = iomap_iter(&iter, ops)) > 0)
	96	iter.processed = iomap_seek_data_iter(&iter, &pos);
	97	if (ret < 0)
	98	return ret;
	99	if (iter.len) /* found data before EOF */
	100	return pos;
3ac1d426 CH	101	/* We've reached the end of the file without finding data */
3ac1d426 CH	102	return -ENXIO;
56a17898 DW	103	}
56a17898 DW	104	EXPORT_SYMBOL_GPL(iomap_seek_data);