xref: /openbmc/linux/fs/iomap/fiemap.c (revision 9a29f5fc)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Copyright (c) 2016-2021 Christoph Hellwig.
4  */
5 #include <linux/module.h>
6 #include <linux/compiler.h>
7 #include <linux/fs.h>
8 #include <linux/iomap.h>
9 #include <linux/fiemap.h>
10 #include <linux/pagemap.h>
11 
12 static int iomap_to_fiemap(struct fiemap_extent_info *fi,
13 		const struct iomap *iomap, u32 flags)
14 {
15 	switch (iomap->type) {
16 	case IOMAP_HOLE:
17 		/* skip holes */
18 		return 0;
19 	case IOMAP_DELALLOC:
20 		flags |= FIEMAP_EXTENT_DELALLOC | FIEMAP_EXTENT_UNKNOWN;
21 		break;
22 	case IOMAP_MAPPED:
23 		break;
24 	case IOMAP_UNWRITTEN:
25 		flags |= FIEMAP_EXTENT_UNWRITTEN;
26 		break;
27 	case IOMAP_INLINE:
28 		flags |= FIEMAP_EXTENT_DATA_INLINE;
29 		break;
30 	}
31 
32 	if (iomap->flags & IOMAP_F_MERGED)
33 		flags |= FIEMAP_EXTENT_MERGED;
34 	if (iomap->flags & IOMAP_F_SHARED)
35 		flags |= FIEMAP_EXTENT_SHARED;
36 
37 	return fiemap_fill_next_extent(fi, iomap->offset,
38 			iomap->addr != IOMAP_NULL_ADDR ? iomap->addr : 0,
39 			iomap->length, flags);
40 }
41 
42 static loff_t iomap_fiemap_iter(const struct iomap_iter *iter,
43 		struct fiemap_extent_info *fi, struct iomap *prev)
44 {
45 	int ret;
46 
47 	if (iter->iomap.type == IOMAP_HOLE)
48 		return iomap_length(iter);
49 
50 	ret = iomap_to_fiemap(fi, prev, 0);
51 	*prev = iter->iomap;
52 	switch (ret) {
53 	case 0:		/* success */
54 		return iomap_length(iter);
55 	case 1:		/* extent array full */
56 		return 0;
57 	default:	/* error */
58 		return ret;
59 	}
60 }
61 
62 int iomap_fiemap(struct inode *inode, struct fiemap_extent_info *fi,
63 		u64 start, u64 len, const struct iomap_ops *ops)
64 {
65 	struct iomap_iter iter = {
66 		.inode		= inode,
67 		.pos		= start,
68 		.len		= len,
69 		.flags		= IOMAP_REPORT,
70 	};
71 	struct iomap prev = {
72 		.type		= IOMAP_HOLE,
73 	};
74 	int ret;
75 
76 	ret = fiemap_prep(inode, fi, start, &iter.len, 0);
77 	if (ret)
78 		return ret;
79 
80 	while ((ret = iomap_iter(&iter, ops)) > 0)
81 		iter.processed = iomap_fiemap_iter(&iter, fi, &prev);
82 
83 	if (prev.type != IOMAP_HOLE) {
84 		ret = iomap_to_fiemap(fi, &prev, FIEMAP_EXTENT_LAST);
85 		if (ret < 0)
86 			return ret;
87 	}
88 
89 	/* inode with no (attribute) mapping will give ENOENT */
90 	if (ret < 0 && ret != -ENOENT)
91 		return ret;
92 	return 0;
93 }
94 EXPORT_SYMBOL_GPL(iomap_fiemap);
95 
96 /* legacy ->bmap interface.  0 is the error return (!) */
97 sector_t
98 iomap_bmap(struct address_space *mapping, sector_t bno,
99 		const struct iomap_ops *ops)
100 {
101 	struct iomap_iter iter = {
102 		.inode	= mapping->host,
103 		.pos	= (loff_t)bno << mapping->host->i_blkbits,
104 		.len	= i_blocksize(mapping->host),
105 		.flags	= IOMAP_REPORT,
106 	};
107 	const unsigned int blkshift = mapping->host->i_blkbits - SECTOR_SHIFT;
108 	int ret;
109 
110 	if (filemap_write_and_wait(mapping))
111 		return 0;
112 
113 	bno = 0;
114 	while ((ret = iomap_iter(&iter, ops)) > 0) {
115 		if (iter.iomap.type == IOMAP_MAPPED)
116 			bno = iomap_sector(&iter.iomap, iter.pos) >> blkshift;
117 		/* leave iter.processed unset to abort loop */
118 	}
119 	if (ret)
120 		return 0;
121 
122 	return bno;
123 }
124 EXPORT_SYMBOL_GPL(iomap_bmap);
125