Commit | Line | Data |
---|---|---|
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 */ | |
21 | }; | |
22 | ||
23 | /* | |
24 | * Collect physical extents for this swap file. Physical extents reported to | |
25 | * the swap code must be trimmed to align to a page boundary. The logical | |
26 | * offset within the file is irrelevant since the swapfile code maps logical | |
27 | * page numbers of the swap device to the physical page-aligned extents. | |
28 | */ | |
29 | static int iomap_swapfile_add_extent(struct iomap_swapfile_info *isi) | |
30 | { | |
31 | struct iomap *iomap = &isi->iomap; | |
32 | unsigned long nr_pages; | |
33 | uint64_t first_ppage; | |
34 | uint64_t first_ppage_reported; | |
35 | uint64_t next_ppage; | |
36 | int error; | |
37 | ||
38 | /* | |
39 | * Round the start up and the end down so that the physical | |
40 | * extent aligns to a page boundary. | |
41 | */ | |
42 | first_ppage = ALIGN(iomap->addr, PAGE_SIZE) >> PAGE_SHIFT; | |
43 | next_ppage = ALIGN_DOWN(iomap->addr + iomap->length, PAGE_SIZE) >> | |
44 | PAGE_SHIFT; | |
45 | ||
46 | /* Skip too-short physical extents. */ | |
47 | if (first_ppage >= next_ppage) | |
48 | return 0; | |
49 | nr_pages = next_ppage - first_ppage; | |
50 | ||
51 | /* | |
52 | * Calculate how much swap space we're adding; the first page contains | |
53 | * the swap header and doesn't count. The mm still wants that first | |
54 | * page fed to add_swap_extent, however. | |
55 | */ | |
56 | first_ppage_reported = first_ppage; | |
57 | if (iomap->offset == 0) | |
58 | first_ppage_reported++; | |
59 | if (isi->lowest_ppage > first_ppage_reported) | |
60 | isi->lowest_ppage = first_ppage_reported; | |
61 | if (isi->highest_ppage < (next_ppage - 1)) | |
62 | isi->highest_ppage = next_ppage - 1; | |
63 | ||
64 | /* Add extent, set up for the next call. */ | |
65 | error = add_swap_extent(isi->sis, isi->nr_pages, nr_pages, first_ppage); | |
66 | if (error < 0) | |
67 | return error; | |
68 | isi->nr_extents += error; | |
69 | isi->nr_pages += nr_pages; | |
70 | return 0; | |
71 | } | |
72 | ||
73 | /* | |
74 | * Accumulate iomaps for this swap file. We have to accumulate iomaps because | |
75 | * swap only cares about contiguous page-aligned physical extents and makes no | |
76 | * distinction between written and unwritten extents. | |
77 | */ | |
78 | static loff_t iomap_swapfile_activate_actor(struct inode *inode, loff_t pos, | |
79 | loff_t count, void *data, struct iomap *iomap) | |
80 | { | |
81 | struct iomap_swapfile_info *isi = data; | |
82 | int error; | |
83 | ||
84 | switch (iomap->type) { | |
85 | case IOMAP_MAPPED: | |
86 | case IOMAP_UNWRITTEN: | |
87 | /* Only real or unwritten extents. */ | |
88 | break; | |
89 | case IOMAP_INLINE: | |
90 | /* No inline data. */ | |
91 | pr_err("swapon: file is inline\n"); | |
92 | return -EINVAL; | |
93 | default: | |
94 | pr_err("swapon: file has unallocated extents\n"); | |
95 | return -EINVAL; | |
96 | } | |
97 | ||
98 | /* No uncommitted metadata or shared blocks. */ | |
99 | if (iomap->flags & IOMAP_F_DIRTY) { | |
100 | pr_err("swapon: file is not committed\n"); | |
101 | return -EINVAL; | |
102 | } | |
103 | if (iomap->flags & IOMAP_F_SHARED) { | |
104 | pr_err("swapon: file has shared extents\n"); | |
105 | return -EINVAL; | |
106 | } | |
107 | ||
108 | /* Only one bdev per swap file. */ | |
109 | if (iomap->bdev != isi->sis->bdev) { | |
110 | pr_err("swapon: file is on multiple devices\n"); | |
111 | return -EINVAL; | |
112 | } | |
113 | ||
114 | if (isi->iomap.length == 0) { | |
115 | /* No accumulated extent, so just store it. */ | |
116 | memcpy(&isi->iomap, iomap, sizeof(isi->iomap)); | |
117 | } else if (isi->iomap.addr + isi->iomap.length == iomap->addr) { | |
118 | /* Append this to the accumulated extent. */ | |
119 | isi->iomap.length += iomap->length; | |
120 | } else { | |
121 | /* Otherwise, add the retained iomap and store this one. */ | |
122 | error = iomap_swapfile_add_extent(isi); | |
123 | if (error) | |
124 | return error; | |
125 | memcpy(&isi->iomap, iomap, sizeof(isi->iomap)); | |
126 | } | |
127 | return count; | |
128 | } | |
129 | ||
130 | /* | |
131 | * Iterate a swap file's iomaps to construct physical extents that can be | |
132 | * passed to the swapfile subsystem. | |
133 | */ | |
134 | int iomap_swapfile_activate(struct swap_info_struct *sis, | |
135 | struct file *swap_file, sector_t *pagespan, | |
136 | const struct iomap_ops *ops) | |
137 | { | |
138 | struct iomap_swapfile_info isi = { | |
139 | .sis = sis, | |
140 | .lowest_ppage = (sector_t)-1ULL, | |
141 | }; | |
142 | struct address_space *mapping = swap_file->f_mapping; | |
143 | struct inode *inode = mapping->host; | |
144 | loff_t pos = 0; | |
145 | loff_t len = ALIGN_DOWN(i_size_read(inode), PAGE_SIZE); | |
146 | loff_t ret; | |
147 | ||
148 | /* | |
149 | * Persist all file mapping metadata so that we won't have any | |
150 | * IOMAP_F_DIRTY iomaps. | |
151 | */ | |
152 | ret = vfs_fsync(swap_file, 1); | |
153 | if (ret) | |
154 | return ret; | |
155 | ||
156 | while (len > 0) { | |
157 | ret = iomap_apply(inode, pos, len, IOMAP_REPORT, | |
158 | ops, &isi, iomap_swapfile_activate_actor); | |
159 | if (ret <= 0) | |
160 | return ret; | |
161 | ||
162 | pos += ret; | |
163 | len -= ret; | |
164 | } | |
165 | ||
166 | if (isi.iomap.length) { | |
167 | ret = iomap_swapfile_add_extent(&isi); | |
168 | if (ret) | |
169 | return ret; | |
170 | } | |
171 | ||
172 | *pagespan = 1 + isi.highest_ppage - isi.lowest_ppage; | |
173 | sis->max = isi.nr_pages; | |
174 | sis->pages = isi.nr_pages - 1; | |
175 | sis->highest_bit = isi.nr_pages - 1; | |
176 | return isi.nr_extents; | |
177 | } | |
178 | EXPORT_SYMBOL_GPL(iomap_swapfile_activate); |