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a45c0ecc DW |
1 | // SPDX-License-Identifier: GPL-2.0 |
2 | /* | |
3 | * Copyright (C) 2018 Oracle. All Rights Reserved. | |
4 | * Author: Darrick J. Wong <darrick.wong@oracle.com> | |
5 | */ | |
6 | #include <linux/module.h> | |
7 | #include <linux/compiler.h> | |
8 | #include <linux/fs.h> | |
9 | #include <linux/iomap.h> | |
10 | #include <linux/swap.h> | |
11 | ||
a45c0ecc DW |
12 | /* Swapfile activation */ |
13 | ||
14 | struct iomap_swapfile_info { | |
15 | struct iomap iomap; /* accumulated iomap */ | |
16 | struct swap_info_struct *sis; | |
17 | uint64_t lowest_ppage; /* lowest physical addr seen (pages) */ | |
18 | uint64_t highest_ppage; /* highest physical addr seen (pages) */ | |
19 | unsigned long nr_pages; /* number of pages collected */ | |
20 | int nr_extents; /* extent count */ | |
ad89b66c | 21 | struct file *file; |
a45c0ecc DW |
22 | }; |
23 | ||
24 | /* | |
25 | * Collect physical extents for this swap file. Physical extents reported to | |
26 | * the swap code must be trimmed to align to a page boundary. The logical | |
27 | * offset within the file is irrelevant since the swapfile code maps logical | |
28 | * page numbers of the swap device to the physical page-aligned extents. | |
29 | */ | |
30 | static int iomap_swapfile_add_extent(struct iomap_swapfile_info *isi) | |
31 | { | |
32 | struct iomap *iomap = &isi->iomap; | |
33 | unsigned long nr_pages; | |
36ca7943 | 34 | unsigned long max_pages; |
a45c0ecc DW |
35 | uint64_t first_ppage; |
36 | uint64_t first_ppage_reported; | |
37 | uint64_t next_ppage; | |
38 | int error; | |
39 | ||
36ca7943 XY |
40 | if (unlikely(isi->nr_pages >= isi->sis->max)) |
41 | return 0; | |
42 | max_pages = isi->sis->max - isi->nr_pages; | |
43 | ||
a45c0ecc DW |
44 | /* |
45 | * Round the start up and the end down so that the physical | |
46 | * extent aligns to a page boundary. | |
47 | */ | |
48 | first_ppage = ALIGN(iomap->addr, PAGE_SIZE) >> PAGE_SHIFT; | |
49 | next_ppage = ALIGN_DOWN(iomap->addr + iomap->length, PAGE_SIZE) >> | |
50 | PAGE_SHIFT; | |
51 | ||
52 | /* Skip too-short physical extents. */ | |
53 | if (first_ppage >= next_ppage) | |
54 | return 0; | |
55 | nr_pages = next_ppage - first_ppage; | |
36ca7943 | 56 | nr_pages = min(nr_pages, max_pages); |
a45c0ecc DW |
57 | |
58 | /* | |
59 | * Calculate how much swap space we're adding; the first page contains | |
60 | * the swap header and doesn't count. The mm still wants that first | |
61 | * page fed to add_swap_extent, however. | |
62 | */ | |
63 | first_ppage_reported = first_ppage; | |
64 | if (iomap->offset == 0) | |
65 | first_ppage_reported++; | |
66 | if (isi->lowest_ppage > first_ppage_reported) | |
67 | isi->lowest_ppage = first_ppage_reported; | |
68 | if (isi->highest_ppage < (next_ppage - 1)) | |
69 | isi->highest_ppage = next_ppage - 1; | |
70 | ||
71 | /* Add extent, set up for the next call. */ | |
72 | error = add_swap_extent(isi->sis, isi->nr_pages, nr_pages, first_ppage); | |
73 | if (error < 0) | |
74 | return error; | |
75 | isi->nr_extents += error; | |
76 | isi->nr_pages += nr_pages; | |
77 | return 0; | |
78 | } | |
79 | ||
ad89b66c CH |
80 | static int iomap_swapfile_fail(struct iomap_swapfile_info *isi, const char *str) |
81 | { | |
82 | char *buf, *p = ERR_PTR(-ENOMEM); | |
83 | ||
84 | buf = kmalloc(PATH_MAX, GFP_KERNEL); | |
85 | if (buf) | |
86 | p = file_path(isi->file, buf, PATH_MAX); | |
87 | pr_err("swapon: file %s %s\n", IS_ERR(p) ? "<unknown>" : p, str); | |
88 | kfree(buf); | |
89 | return -EINVAL; | |
90 | } | |
91 | ||
a45c0ecc DW |
92 | /* |
93 | * Accumulate iomaps for this swap file. We have to accumulate iomaps because | |
94 | * swap only cares about contiguous page-aligned physical extents and makes no | |
95 | * distinction between written and unwritten extents. | |
96 | */ | |
3d99a1ce CH |
97 | static loff_t iomap_swapfile_iter(const struct iomap_iter *iter, |
98 | struct iomap *iomap, struct iomap_swapfile_info *isi) | |
a45c0ecc | 99 | { |
a45c0ecc DW |
100 | switch (iomap->type) { |
101 | case IOMAP_MAPPED: | |
102 | case IOMAP_UNWRITTEN: | |
103 | /* Only real or unwritten extents. */ | |
104 | break; | |
105 | case IOMAP_INLINE: | |
106 | /* No inline data. */ | |
ad89b66c | 107 | return iomap_swapfile_fail(isi, "is inline"); |
a45c0ecc | 108 | default: |
ad89b66c | 109 | return iomap_swapfile_fail(isi, "has unallocated extents"); |
a45c0ecc DW |
110 | } |
111 | ||
112 | /* No uncommitted metadata or shared blocks. */ | |
ad89b66c CH |
113 | if (iomap->flags & IOMAP_F_DIRTY) |
114 | return iomap_swapfile_fail(isi, "is not committed"); | |
115 | if (iomap->flags & IOMAP_F_SHARED) | |
116 | return iomap_swapfile_fail(isi, "has shared extents"); | |
a45c0ecc DW |
117 | |
118 | /* Only one bdev per swap file. */ | |
ad89b66c CH |
119 | if (iomap->bdev != isi->sis->bdev) |
120 | return iomap_swapfile_fail(isi, "outside the main device"); | |
a45c0ecc DW |
121 | |
122 | if (isi->iomap.length == 0) { | |
123 | /* No accumulated extent, so just store it. */ | |
124 | memcpy(&isi->iomap, iomap, sizeof(isi->iomap)); | |
125 | } else if (isi->iomap.addr + isi->iomap.length == iomap->addr) { | |
126 | /* Append this to the accumulated extent. */ | |
127 | isi->iomap.length += iomap->length; | |
128 | } else { | |
129 | /* Otherwise, add the retained iomap and store this one. */ | |
3d99a1ce | 130 | int error = iomap_swapfile_add_extent(isi); |
a45c0ecc DW |
131 | if (error) |
132 | return error; | |
133 | memcpy(&isi->iomap, iomap, sizeof(isi->iomap)); | |
134 | } | |
3d99a1ce | 135 | return iomap_length(iter); |
a45c0ecc DW |
136 | } |
137 | ||
138 | /* | |
139 | * Iterate a swap file's iomaps to construct physical extents that can be | |
140 | * passed to the swapfile subsystem. | |
141 | */ | |
142 | int iomap_swapfile_activate(struct swap_info_struct *sis, | |
143 | struct file *swap_file, sector_t *pagespan, | |
144 | const struct iomap_ops *ops) | |
145 | { | |
3d99a1ce CH |
146 | struct inode *inode = swap_file->f_mapping->host; |
147 | struct iomap_iter iter = { | |
148 | .inode = inode, | |
149 | .pos = 0, | |
150 | .len = ALIGN_DOWN(i_size_read(inode), PAGE_SIZE), | |
151 | .flags = IOMAP_REPORT, | |
152 | }; | |
a45c0ecc DW |
153 | struct iomap_swapfile_info isi = { |
154 | .sis = sis, | |
155 | .lowest_ppage = (sector_t)-1ULL, | |
ad89b66c | 156 | .file = swap_file, |
a45c0ecc | 157 | }; |
3d99a1ce | 158 | int ret; |
a45c0ecc DW |
159 | |
160 | /* | |
161 | * Persist all file mapping metadata so that we won't have any | |
162 | * IOMAP_F_DIRTY iomaps. | |
163 | */ | |
164 | ret = vfs_fsync(swap_file, 1); | |
165 | if (ret) | |
166 | return ret; | |
167 | ||
3d99a1ce CH |
168 | while ((ret = iomap_iter(&iter, ops)) > 0) |
169 | iter.processed = iomap_swapfile_iter(&iter, &iter.iomap, &isi); | |
170 | if (ret < 0) | |
171 | return ret; | |
a45c0ecc DW |
172 | |
173 | if (isi.iomap.length) { | |
174 | ret = iomap_swapfile_add_extent(&isi); | |
175 | if (ret) | |
176 | return ret; | |
177 | } | |
178 | ||
5808fecc RH |
179 | /* |
180 | * If this swapfile doesn't contain even a single page-aligned | |
181 | * contiguous range of blocks, reject this useless swapfile to | |
182 | * prevent confusion later on. | |
183 | */ | |
184 | if (isi.nr_pages == 0) { | |
185 | pr_warn("swapon: Cannot find a single usable page in file.\n"); | |
186 | return -EINVAL; | |
187 | } | |
188 | ||
a45c0ecc DW |
189 | *pagespan = 1 + isi.highest_ppage - isi.lowest_ppage; |
190 | sis->max = isi.nr_pages; | |
191 | sis->pages = isi.nr_pages - 1; | |
192 | sis->highest_bit = isi.nr_pages - 1; | |
193 | return isi.nr_extents; | |
194 | } | |
195 | EXPORT_SYMBOL_GPL(iomap_swapfile_activate); |