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
13 static loff_t iomap_seek_hole_iter(const 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 iter->pos, iter->pos + length, SEEK_HOLE);
22 if (*hole_pos == iter->pos + length)
23 return length;
24 return 0;
25 case IOMAP_HOLE:
26 *hole_pos = iter->pos;
27 return 0;
28 default:
29 return length;
30 }
31 }
32
33 loff_t
34 iomap_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, 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;
56 }
57 EXPORT_SYMBOL_GPL(iomap_seek_hole);
58
59 static loff_t iomap_seek_data_iter(const 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 length;
67 case IOMAP_UNWRITTEN:
68 *hole_pos = mapping_seek_hole_data(iter->inode->i_mapping,
69 iter->pos, iter->pos + length, SEEK_DATA);
70 if (*hole_pos < 0)
71 return length;
72 return 0;
73 default:
74 *hole_pos = iter->pos;
75 return 0;
76 }
77 }
78
79 loff_t
80 iomap_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, 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;
101 /* We've reached the end of the file without finding data */
102 return -ENXIO;
103 }
104 EXPORT_SYMBOL_GPL(iomap_seek_data);
105
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