1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Copyright (C) 2010 Red Hat, Inc.
4 * Copyright (c) 2016-2021 Christoph Hellwig.
5 */
6 #include <linux/fs.h>
7 #include <linux/iomap.h>
8 #include "trace.h"
9
iomap_iter_advance(struct iomap_iter * iter)10 static inline int iomap_iter_advance(struct iomap_iter *iter)
11 {
12 /* handle the previous iteration (if any) */
13 if (iter->iomap.length) {
14 if (iter->processed <= 0)
15 return iter->processed;
16 if (WARN_ON_ONCE(iter->processed > iomap_length(iter)))
17 return -EIO;
18 iter->pos += iter->processed;
19 iter->len -= iter->processed;
20 if (!iter->len)
21 return 0;
22 }
23
24 /* clear the state for the next iteration */
25 iter->processed = 0;
26 memset(&iter->iomap, 0, sizeof(iter->iomap));
27 memset(&iter->srcmap, 0, sizeof(iter->srcmap));
28 return 1;
29 }
30
iomap_iter_done(struct iomap_iter * iter)31 static inline void iomap_iter_done(struct iomap_iter *iter)
32 {
33 WARN_ON_ONCE(iter->iomap.offset > iter->pos);
34 WARN_ON_ONCE(iter->iomap.length == 0);
35 WARN_ON_ONCE(iter->iomap.offset + iter->iomap.length <= iter->pos);
36
37 trace_iomap_iter_dstmap(iter->inode, &iter->iomap);
38 if (iter->srcmap.type != IOMAP_HOLE)
39 trace_iomap_iter_srcmap(iter->inode, &iter->srcmap);
40 }
41
42 /**
43 * iomap_iter - iterate over a ranges in a file
44 * @iter: iteration structue
45 * @ops: iomap ops provided by the file system
46 *
47 * Iterate over filesystem-provided space mappings for the provided file range.
48 *
49 * This function handles cleanup of resources acquired for iteration when the
50 * filesystem indicates there are no more space mappings, which means that this
51 * function must be called in a loop that continues as long it returns a
52 * positive value. If 0 or a negative value is returned, the caller must not
53 * return to the loop body. Within a loop body, there are two ways to break out
54 * of the loop body: leave @iter.processed unchanged, or set it to a negative
55 * errno.
56 */
iomap_iter(struct iomap_iter * iter,const struct iomap_ops * ops)57 int iomap_iter(struct iomap_iter *iter, const struct iomap_ops *ops)
58 {
59 int ret;
60
61 if (iter->iomap.length && ops->iomap_end) {
62 ret = ops->iomap_end(iter->inode, iter->pos, iomap_length(iter),
63 iter->processed > 0 ? iter->processed : 0,
64 iter->flags, &iter->iomap);
65 if (ret < 0 && !iter->processed)
66 return ret;
67 }
68
69 trace_iomap_iter(iter, ops, _RET_IP_);
70 ret = iomap_iter_advance(iter);
71 if (ret <= 0)
72 return ret;
73
74 ret = ops->iomap_begin(iter->inode, iter->pos, iter->len, iter->flags,
75 &iter->iomap, &iter->srcmap);
76 if (ret < 0)
77 return ret;
78 iomap_iter_done(iter);
79 return 1;
80 }
81
