1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
|
// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 2010 Red Hat, Inc.
* Copyright (c) 2016-2021 Christoph Hellwig.
*/
#include <linux/iomap.h>
#include "trace.h"
/*
* Release the iter folio batch. Note that the iomap flag is meant to control
* the I/O path for the mapping and may not be set in error situations.
*/
static inline void iomap_iter_clean_fbatch(const struct iomap_iter *iter,
struct iomap *iomap)
{
if (!iter->fbatch)
return;
iomap->flags &= ~IOMAP_F_FOLIO_BATCH;
if (folio_batch_count(iter->fbatch)) {
folio_batch_release(iter->fbatch);
folio_batch_reinit(iter->fbatch);
}
}
/* Advance the current iterator position and decrement the remaining length */
int iomap_iter_advance(struct iomap_iter *iter, u64 count)
{
if (WARN_ON_ONCE(count > iomap_length(iter)))
return -EIO;
iter->pos += count;
iter->len -= count;
return 0;
}
static inline void iomap_iter_done(struct iomap_iter *iter)
{
WARN_ON_ONCE(iter->iomap.offset > iter->pos);
WARN_ON_ONCE(iter->iomap.length == 0);
WARN_ON_ONCE(iter->iomap.offset + iter->iomap.length <= iter->pos);
WARN_ON_ONCE(iter->iomap.flags & IOMAP_F_STALE);
iter->iter_start_pos = iter->pos;
trace_iomap_iter_dstmap(iter->inode, &iter->iomap);
if (iter->srcmap.type != IOMAP_HOLE)
trace_iomap_iter_srcmap(iter->inode, &iter->srcmap);
}
/**
* iomap_iter_continue - decide whether iteration should continue
* @iter: iteration structure
* @iomap: the mapping that was just processed
* @srcmap: the source mapping that was just processed
*
* Helper normally called via iomap_iter_next(). Called after the previous
* mapping has been finished to determine whether there is more of the file
* range left to process.
*
* Returns 1 if there is more work to do, in which case @iomap and @srcmap are
* cleared so the caller can produce the next mapping; zero if the range is
* fully consumed; or a negative errno on error.
*/
int iomap_iter_continue(const struct iomap_iter *iter, struct iomap *iomap,
struct iomap *srcmap, int ret)
{
const bool stale = iomap->flags & IOMAP_F_STALE;
const ssize_t advanced = iter->pos - iter->iter_start_pos;
if (ret < 0 && !advanced)
return ret;
/*
* Use iter->len to determine whether to continue onto the next mapping.
* Explicitly terminate on error status or if the current iter has not
* advanced at all (i.e. no work was done for some reason) unless the
* mapping has been marked stale and needs to be reprocessed.
*/
if (WARN_ON_ONCE(iter->status > 0))
/* detect old return semantics where this would advance */
ret = -EIO;
else if (iter->status < 0)
ret = iter->status;
else if (iter->len == 0 || (!advanced && !stale))
ret = 0;
else
ret = 1;
iomap_iter_clean_fbatch(iter, iomap);
if (ret <= 0)
return ret;
memset(iomap, 0, sizeof(*iomap));
memset(srcmap, 0, sizeof(*srcmap));
return ret;
}
EXPORT_SYMBOL_GPL(iomap_iter_continue);
/**
* iomap_iter - iterate over ranges in a file
* @iter: iteration structure
* @ops: iomap ops provided by the filesystem
*
* Iterate over filesystem-provided space mappings for the provided file range.
*
* This function handles cleanup of resources acquired for iteration when the
* filesystem indicates there are no more space mappings, which means that this
* function must be called in a loop that continues as long it returns a
* positive value. If 0 or a negative value is returned, the caller must not
* return to the loop body. Within a loop body, there are two ways to break out
* of the loop body: leave @iter.status unchanged, or set it to a negative
* errno.
*/
int iomap_iter(struct iomap_iter *iter, const struct iomap_ops *ops)
{
int ret;
trace_iomap_iter(iter, ops, _RET_IP_);
if (ops->iomap_next)
ret = ops->iomap_next(iter, &iter->iomap, &iter->srcmap);
else
ret = iomap_iter_next(iter, &iter->iomap, &iter->srcmap,
ops->iomap_begin, ops->iomap_end);
iter->status = 0;
if (ret > 0)
iomap_iter_done(iter);
else if (ret < 0)
iomap_iter_clean_fbatch(iter, &iter->iomap);
return ret;
}
|
