1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (C) 2017 Red Hat, Inc.
4 * Copyright (c) 2018-2021 Christoph Hellwig.
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
13static int iomap_seek_hole_iter(struct iomap_iter *iter,
14 loff_t *hole_pos)
15{
16 loff_t length = iomap_length(iter);
17
18 switch (iter->iomap.type) {
19 case IOMAP_UNWRITTEN:
20 *hole_pos = mapping_seek_hole_data(iter->inode->i_mapping,
21 start: iter->pos, end: iter->pos + length, SEEK_HOLE);
22 if (*hole_pos == iter->pos + length)
23 return iomap_iter_advance(iter, count: &length);
24 return 0;
25 case IOMAP_HOLE:
26 *hole_pos = iter->pos;
27 return 0;
28 default:
29 return iomap_iter_advance(iter, count: &length);
30 }
31}
32
33loff_t
34iomap_seek_hole(struct inode *inode, loff_t pos, const struct iomap_ops *ops)
35{
36 loff_t size = i_size_read(inode);
37 struct iomap_iter iter = {
38 .inode = inode,
39 .pos = pos,
40 .flags = IOMAP_REPORT,
41 };
42 int ret;
43
44 /* Nothing to be found before or beyond the end of the file. */
45 if (pos < 0 || pos >= size)
46 return -ENXIO;
47
48 iter.len = size - pos;
49 while ((ret = iomap_iter(iter: &iter, ops)) > 0)
50 iter.status = iomap_seek_hole_iter(iter: &iter, hole_pos: &pos);
51 if (ret < 0)
52 return ret;
53 if (iter.len) /* found hole before EOF */
54 return pos;
55 return size;
56}
57EXPORT_SYMBOL_GPL(iomap_seek_hole);
58
59static int iomap_seek_data_iter(struct iomap_iter *iter,
60 loff_t *hole_pos)
61{
62 loff_t length = iomap_length(iter);
63
64 switch (iter->iomap.type) {
65 case IOMAP_HOLE:
66 return iomap_iter_advance(iter, count: &length);
67 case IOMAP_UNWRITTEN:
68 *hole_pos = mapping_seek_hole_data(iter->inode->i_mapping,
69 start: iter->pos, end: iter->pos + length, SEEK_DATA);
70 if (*hole_pos < 0)
71 return iomap_iter_advance(iter, count: &length);
72 return 0;
73 default:
74 *hole_pos = iter->pos;
75 return 0;
76 }
77}
78
79loff_t
80iomap_seek_data(struct inode *inode, loff_t pos, const struct iomap_ops *ops)
81{
82 loff_t size = i_size_read(inode);
83 struct iomap_iter iter = {
84 .inode = inode,
85 .pos = pos,
86 .flags = IOMAP_REPORT,
87 };
88 int ret;
89
90 /* Nothing to be found before or beyond the end of the file. */
91 if (pos < 0 || pos >= size)
92 return -ENXIO;
93
94 iter.len = size - pos;
95 while ((ret = iomap_iter(iter: &iter, ops)) > 0)
96 iter.status = iomap_seek_data_iter(iter: &iter, hole_pos: &pos);
97 if (ret < 0)
98 return ret;
99 if (iter.len) /* found data before EOF */
100 return pos;
101 /* We've reached the end of the file without finding data */
102 return -ENXIO;
103}
104EXPORT_SYMBOL_GPL(iomap_seek_data);
105

source code of linux/fs/iomap/seek.c