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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 : : 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 : 0 : static int iomap_swapfile_add_extent(struct iomap_swapfile_info *isi) 30 : : { 31 : 0 : struct iomap *iomap = &isi->iomap; 32 : 0 : unsigned long nr_pages; 33 : 0 : uint64_t first_ppage; 34 : 0 : uint64_t first_ppage_reported; 35 : 0 : uint64_t next_ppage; 36 : 0 : 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 : 0 : first_ppage = ALIGN(iomap->addr, PAGE_SIZE) >> PAGE_SHIFT; 43 : 0 : next_ppage = ALIGN_DOWN(iomap->addr + iomap->length, PAGE_SIZE) >> 44 : : PAGE_SHIFT; 45 : : 46 : : /* Skip too-short physical extents. */ 47 [ # # ]: 0 : if (first_ppage >= next_ppage) 48 : : return 0; 49 : 0 : 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 : 0 : first_ppage_reported = first_ppage; 57 [ # # ]: 0 : if (iomap->offset == 0) 58 : 0 : first_ppage_reported++; 59 [ # # ]: 0 : if (isi->lowest_ppage > first_ppage_reported) 60 : 0 : isi->lowest_ppage = first_ppage_reported; 61 [ # # ]: 0 : if (isi->highest_ppage < (next_ppage - 1)) 62 : 0 : isi->highest_ppage = next_ppage - 1; 63 : : 64 : : /* Add extent, set up for the next call. */ 65 : 0 : error = add_swap_extent(isi->sis, isi->nr_pages, nr_pages, first_ppage); 66 [ # # ]: 0 : if (error < 0) 67 : : return error; 68 : 0 : isi->nr_extents += error; 69 : 0 : isi->nr_pages += nr_pages; 70 : 0 : 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 : 0 : static loff_t iomap_swapfile_activate_actor(struct inode *inode, loff_t pos, 79 : : loff_t count, void *data, struct iomap *iomap, 80 : : struct iomap *srcmap) 81 : : { 82 : 0 : struct iomap_swapfile_info *isi = data; 83 : 0 : int error; 84 : : 85 [ # # # ]: 0 : switch (iomap->type) { 86 : : case IOMAP_MAPPED: 87 : : case IOMAP_UNWRITTEN: 88 : : /* Only real or unwritten extents. */ 89 : 0 : break; 90 : 0 : case IOMAP_INLINE: 91 : : /* No inline data. */ 92 : 0 : pr_err("swapon: file is inline\n"); 93 : 0 : return -EINVAL; 94 : 0 : default: 95 : 0 : pr_err("swapon: file has unallocated extents\n"); 96 : 0 : return -EINVAL; 97 : : } 98 : : 99 : : /* No uncommitted metadata or shared blocks. */ 100 [ # # ]: 0 : if (iomap->flags & IOMAP_F_DIRTY) { 101 : 0 : pr_err("swapon: file is not committed\n"); 102 : 0 : return -EINVAL; 103 : : } 104 [ # # ]: 0 : if (iomap->flags & IOMAP_F_SHARED) { 105 : 0 : pr_err("swapon: file has shared extents\n"); 106 : 0 : return -EINVAL; 107 : : } 108 : : 109 : : /* Only one bdev per swap file. */ 110 [ # # ]: 0 : if (iomap->bdev != isi->sis->bdev) { 111 : 0 : pr_err("swapon: file is on multiple devices\n"); 112 : 0 : return -EINVAL; 113 : : } 114 : : 115 [ # # ]: 0 : if (isi->iomap.length == 0) { 116 : : /* No accumulated extent, so just store it. */ 117 : 0 : memcpy(&isi->iomap, iomap, sizeof(isi->iomap)); 118 [ # # ]: 0 : } else if (isi->iomap.addr + isi->iomap.length == iomap->addr) { 119 : : /* Append this to the accumulated extent. */ 120 : 0 : isi->iomap.length += iomap->length; 121 : : } else { 122 : : /* Otherwise, add the retained iomap and store this one. */ 123 : 0 : error = iomap_swapfile_add_extent(isi); 124 [ # # ]: 0 : if (error) 125 : 0 : return error; 126 : 0 : memcpy(&isi->iomap, iomap, sizeof(isi->iomap)); 127 : : } 128 : : return count; 129 : : } 130 : : 131 : : /* 132 : : * Iterate a swap file's iomaps to construct physical extents that can be 133 : : * passed to the swapfile subsystem. 134 : : */ 135 : 0 : int iomap_swapfile_activate(struct swap_info_struct *sis, 136 : : struct file *swap_file, sector_t *pagespan, 137 : : const struct iomap_ops *ops) 138 : : { 139 : 0 : struct iomap_swapfile_info isi = { 140 : : .sis = sis, 141 : : .lowest_ppage = (sector_t)-1ULL, 142 : : }; 143 : 0 : struct address_space *mapping = swap_file->f_mapping; 144 : 0 : struct inode *inode = mapping->host; 145 : 0 : loff_t pos = 0; 146 : 0 : loff_t len = ALIGN_DOWN(i_size_read(inode), PAGE_SIZE); 147 : 0 : loff_t ret; 148 : : 149 : : /* 150 : : * Persist all file mapping metadata so that we won't have any 151 : : * IOMAP_F_DIRTY iomaps. 152 : : */ 153 : 0 : ret = vfs_fsync(swap_file, 1); 154 [ # # ]: 0 : if (ret) 155 : : return ret; 156 : : 157 [ # # ]: 0 : while (len > 0) { 158 : 0 : ret = iomap_apply(inode, pos, len, IOMAP_REPORT, 159 : : ops, &isi, iomap_swapfile_activate_actor); 160 [ # # ]: 0 : if (ret <= 0) 161 : 0 : return ret; 162 : : 163 : 0 : pos += ret; 164 : 0 : len -= ret; 165 : : } 166 : : 167 [ # # ]: 0 : if (isi.iomap.length) { 168 : 0 : ret = iomap_swapfile_add_extent(&isi); 169 [ # # ]: 0 : if (ret) 170 : : return ret; 171 : : } 172 : : 173 : 0 : *pagespan = 1 + isi.highest_ppage - isi.lowest_ppage; 174 : 0 : sis->max = isi.nr_pages; 175 : 0 : sis->pages = isi.nr_pages - 1; 176 : 0 : sis->highest_bit = isi.nr_pages - 1; 177 : 0 : return isi.nr_extents; 178 : : } 179 : : EXPORT_SYMBOL_GPL(iomap_swapfile_activate);