1 // SPDX-License-Identifier: GPL-2.0-or-later 1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /* 2 /*
3 * Squashfs - a compressed read only filesyste 3 * Squashfs - a compressed read only filesystem for Linux
4 * 4 *
5 * Copyright (c) 2002, 2003, 2004, 2005, 2006, 5 * Copyright (c) 2002, 2003, 2004, 2005, 2006, 2007, 2008
6 * Phillip Lougher <phillip@squashfs.org.uk> 6 * Phillip Lougher <phillip@squashfs.org.uk>
7 * 7 *
8 * block.c 8 * block.c
9 */ 9 */
10 10
11 /* 11 /*
12 * This file implements the low-level routines 12 * This file implements the low-level routines to read and decompress
13 * datablocks and metadata blocks. 13 * datablocks and metadata blocks.
14 */ 14 */
15 15
16 #include <linux/blkdev.h> 16 #include <linux/blkdev.h>
17 #include <linux/fs.h> 17 #include <linux/fs.h>
18 #include <linux/vfs.h> 18 #include <linux/vfs.h>
19 #include <linux/slab.h> 19 #include <linux/slab.h>
20 #include <linux/pagemap.h> <<
21 #include <linux/string.h> 20 #include <linux/string.h>
>> 21 #include <linux/buffer_head.h>
22 #include <linux/bio.h> 22 #include <linux/bio.h>
23 23
24 #include "squashfs_fs.h" 24 #include "squashfs_fs.h"
25 #include "squashfs_fs_sb.h" 25 #include "squashfs_fs_sb.h"
26 #include "squashfs.h" 26 #include "squashfs.h"
27 #include "decompressor.h" 27 #include "decompressor.h"
28 #include "page_actor.h" 28 #include "page_actor.h"
29 29
30 /* 30 /*
31 * Returns the amount of bytes copied to the p 31 * Returns the amount of bytes copied to the page actor.
32 */ 32 */
33 static int copy_bio_to_actor(struct bio *bio, 33 static int copy_bio_to_actor(struct bio *bio,
34 struct squashfs_p 34 struct squashfs_page_actor *actor,
35 int offset, int r 35 int offset, int req_length)
36 { 36 {
37 void *actor_addr; 37 void *actor_addr;
38 struct bvec_iter_all iter_all = {}; 38 struct bvec_iter_all iter_all = {};
39 struct bio_vec *bvec = bvec_init_iter_ 39 struct bio_vec *bvec = bvec_init_iter_all(&iter_all);
40 int copied_bytes = 0; 40 int copied_bytes = 0;
41 int actor_offset = 0; 41 int actor_offset = 0;
42 42
43 squashfs_actor_nobuff(actor); 43 squashfs_actor_nobuff(actor);
44 actor_addr = squashfs_first_page(actor 44 actor_addr = squashfs_first_page(actor);
45 45
46 if (WARN_ON_ONCE(!bio_next_segment(bio 46 if (WARN_ON_ONCE(!bio_next_segment(bio, &iter_all)))
47 return 0; 47 return 0;
48 48
49 while (copied_bytes < req_length) { 49 while (copied_bytes < req_length) {
50 int bytes_to_copy = min_t(int, 50 int bytes_to_copy = min_t(int, bvec->bv_len - offset,
51 PAGE 51 PAGE_SIZE - actor_offset);
52 52
53 bytes_to_copy = min_t(int, byt 53 bytes_to_copy = min_t(int, bytes_to_copy,
54 req_leng 54 req_length - copied_bytes);
55 if (!IS_ERR(actor_addr)) 55 if (!IS_ERR(actor_addr))
56 memcpy(actor_addr + ac 56 memcpy(actor_addr + actor_offset, bvec_virt(bvec) +
57 offset 57 offset, bytes_to_copy);
58 58
59 actor_offset += bytes_to_copy; 59 actor_offset += bytes_to_copy;
60 copied_bytes += bytes_to_copy; 60 copied_bytes += bytes_to_copy;
61 offset += bytes_to_copy; 61 offset += bytes_to_copy;
62 62
63 if (actor_offset >= PAGE_SIZE) 63 if (actor_offset >= PAGE_SIZE) {
64 actor_addr = squashfs_ 64 actor_addr = squashfs_next_page(actor);
65 if (!actor_addr) 65 if (!actor_addr)
66 break; 66 break;
67 actor_offset = 0; 67 actor_offset = 0;
68 } 68 }
69 if (offset >= bvec->bv_len) { 69 if (offset >= bvec->bv_len) {
70 if (!bio_next_segment( 70 if (!bio_next_segment(bio, &iter_all))
71 break; 71 break;
72 offset = 0; 72 offset = 0;
73 } 73 }
74 } 74 }
75 squashfs_finish_page(actor); 75 squashfs_finish_page(actor);
76 return copied_bytes; 76 return copied_bytes;
77 } 77 }
78 78
79 static int squashfs_bio_read_cached(struct bio <<
80 struct address_space *cache_ma <<
81 u64 read_start, u64 read_end, <<
82 { <<
83 struct page *head_to_cache = NULL, *ta <<
84 struct block_device *bdev = fullbio->b <<
85 int start_idx = 0, end_idx = 0; <<
86 struct bvec_iter_all iter_all; <<
87 struct bio *bio = NULL; <<
88 struct bio_vec *bv; <<
89 int idx = 0; <<
90 int err = 0; <<
91 <<
92 bio_for_each_segment_all(bv, fullbio, <<
93 struct page *page = bv->bv_pag <<
94 <<
95 if (page->mapping == cache_map <<
96 idx++; <<
97 continue; <<
98 } <<
99 <<
100 /* <<
101 * We only use this when the d <<
102 * the page size, so read_star <<
103 * <<
104 * Compare these to the origin <<
105 * only cache pages which were <<
106 * are the ones which are like <<
107 * adjacent blocks. <<
108 */ <<
109 if (idx == 0 && index != read_ <<
110 head_to_cache = page; <<
111 else if (idx == page_count - 1 <<
112 tail_to_cache = page; <<
113 <<
114 if (!bio || idx != end_idx) { <<
115 struct bio *new = bio_ <<
116 <<
117 <<
118 if (bio) { <<
119 bio_trim(bio, <<
120 (end_ <<
121 bio_chain(bio, <<
122 submit_bio(bio <<
123 } <<
124 <<
125 bio = new; <<
126 start_idx = idx; <<
127 } <<
128 <<
129 idx++; <<
130 end_idx = idx; <<
131 } <<
132 <<
133 if (bio) { <<
134 bio_trim(bio, start_idx * PAGE <<
135 (end_idx - start_idx) <<
136 err = submit_bio_wait(bio); <<
137 bio_put(bio); <<
138 } <<
139 <<
140 if (err) <<
141 return err; <<
142 <<
143 if (head_to_cache) { <<
144 int ret = add_to_page_cache_lr <<
145 <<
146 <<
147 <<
148 if (!ret) { <<
149 SetPageUptodate(head_t <<
150 unlock_page(head_to_ca <<
151 } <<
152 <<
153 } <<
154 <<
155 if (tail_to_cache) { <<
156 int ret = add_to_page_cache_lr <<
157 <<
158 <<
159 <<
160 if (!ret) { <<
161 SetPageUptodate(tail_t <<
162 unlock_page(tail_to_ca <<
163 } <<
164 } <<
165 <<
166 return 0; <<
167 } <<
168 <<
169 static struct page *squashfs_get_cache_page(st <<
170 pg <<
171 { <<
172 struct page *page; <<
173 <<
174 if (!mapping) <<
175 return NULL; <<
176 <<
177 page = find_get_page(mapping, index); <<
178 if (!page) <<
179 return NULL; <<
180 <<
181 if (!PageUptodate(page)) { <<
182 put_page(page); <<
183 return NULL; <<
184 } <<
185 <<
186 return page; <<
187 } <<
188 <<
189 static int squashfs_bio_read(struct super_bloc 79 static int squashfs_bio_read(struct super_block *sb, u64 index, int length,
190 struct bio **biop 80 struct bio **biop, int *block_offset)
191 { 81 {
192 struct squashfs_sb_info *msblk = sb->s 82 struct squashfs_sb_info *msblk = sb->s_fs_info;
193 struct address_space *cache_mapping = <<
194 const u64 read_start = round_down(inde 83 const u64 read_start = round_down(index, msblk->devblksize);
195 const sector_t block = read_start >> m 84 const sector_t block = read_start >> msblk->devblksize_log2;
196 const u64 read_end = round_up(index + 85 const u64 read_end = round_up(index + length, msblk->devblksize);
197 const sector_t block_end = read_end >> 86 const sector_t block_end = read_end >> msblk->devblksize_log2;
198 int offset = read_start - round_down(i 87 int offset = read_start - round_down(index, PAGE_SIZE);
199 int total_len = (block_end - block) << 88 int total_len = (block_end - block) << msblk->devblksize_log2;
200 const int page_count = DIV_ROUND_UP(to 89 const int page_count = DIV_ROUND_UP(total_len + offset, PAGE_SIZE);
201 int error, i; 90 int error, i;
202 struct bio *bio; 91 struct bio *bio;
203 92
204 bio = bio_kmalloc(page_count, GFP_NOIO 93 bio = bio_kmalloc(page_count, GFP_NOIO);
205 if (!bio) 94 if (!bio)
206 return -ENOMEM; 95 return -ENOMEM;
207 bio_init(bio, sb->s_bdev, bio->bi_inli 96 bio_init(bio, sb->s_bdev, bio->bi_inline_vecs, page_count, REQ_OP_READ);
208 bio->bi_iter.bi_sector = block * (msbl 97 bio->bi_iter.bi_sector = block * (msblk->devblksize >> SECTOR_SHIFT);
209 98
210 for (i = 0; i < page_count; ++i) { 99 for (i = 0; i < page_count; ++i) {
211 unsigned int len = 100 unsigned int len =
212 min_t(unsigned int, PA 101 min_t(unsigned int, PAGE_SIZE - offset, total_len);
213 pgoff_t index = (read_start >> !! 102 struct page *page = alloc_page(GFP_NOIO);
214 struct page *page; <<
215 <<
216 page = squashfs_get_cache_page <<
217 if (!page) <<
218 page = alloc_page(GFP_ <<
219 103
220 if (!page) { 104 if (!page) {
221 error = -ENOMEM; 105 error = -ENOMEM;
222 goto out_free_bio; 106 goto out_free_bio;
223 } 107 }
224 !! 108 if (!bio_add_page(bio, page, len, offset)) {
225 /* !! 109 error = -EIO;
226 * Use the __ version to avoid !! 110 goto out_free_bio;
227 * to be separate when we chec !! 111 }
228 */ <<
229 __bio_add_page(bio, page, len, <<
230 offset = 0; 112 offset = 0;
231 total_len -= len; 113 total_len -= len;
232 } 114 }
233 115
234 if (cache_mapping) !! 116 error = submit_bio_wait(bio);
235 error = squashfs_bio_read_cach <<
236 <<
237 <<
238 else <<
239 error = submit_bio_wait(bio); <<
240 if (error) 117 if (error)
241 goto out_free_bio; 118 goto out_free_bio;
242 119
243 *biop = bio; 120 *biop = bio;
244 *block_offset = index & ((1 << msblk-> 121 *block_offset = index & ((1 << msblk->devblksize_log2) - 1);
245 return 0; 122 return 0;
246 123
247 out_free_bio: 124 out_free_bio:
248 bio_free_pages(bio); 125 bio_free_pages(bio);
249 bio_uninit(bio); 126 bio_uninit(bio);
250 kfree(bio); 127 kfree(bio);
251 return error; 128 return error;
252 } 129 }
253 130
254 /* 131 /*
255 * Read and decompress a metadata block or dat 132 * Read and decompress a metadata block or datablock. Length is non-zero
256 * if a datablock is being read (the size is s 133 * if a datablock is being read (the size is stored elsewhere in the
257 * filesystem), otherwise the length is obtain 134 * filesystem), otherwise the length is obtained from the first two bytes of
258 * the metadata block. A bit in the length fi 135 * the metadata block. A bit in the length field indicates if the block
259 * is stored uncompressed in the filesystem (u 136 * is stored uncompressed in the filesystem (usually because compression
260 * generated a larger block - this does occasi 137 * generated a larger block - this does occasionally happen with compression
261 * algorithms). 138 * algorithms).
262 */ 139 */
263 int squashfs_read_data(struct super_block *sb, 140 int squashfs_read_data(struct super_block *sb, u64 index, int length,
264 u64 *next_index, struct 141 u64 *next_index, struct squashfs_page_actor *output)
265 { 142 {
266 struct squashfs_sb_info *msblk = sb->s 143 struct squashfs_sb_info *msblk = sb->s_fs_info;
267 struct bio *bio = NULL; 144 struct bio *bio = NULL;
268 int compressed; 145 int compressed;
269 int res; 146 int res;
270 int offset; 147 int offset;
271 148
272 if (length) { 149 if (length) {
273 /* 150 /*
274 * Datablock. 151 * Datablock.
275 */ 152 */
276 compressed = SQUASHFS_COMPRESS 153 compressed = SQUASHFS_COMPRESSED_BLOCK(length);
277 length = SQUASHFS_COMPRESSED_S 154 length = SQUASHFS_COMPRESSED_SIZE_BLOCK(length);
278 TRACE("Block @ 0x%llx, %scompr 155 TRACE("Block @ 0x%llx, %scompressed size %d, src size %d\n",
279 index, compressed ? "" 156 index, compressed ? "" : "un", length, output->length);
280 } else { 157 } else {
281 /* 158 /*
282 * Metadata block. 159 * Metadata block.
283 */ 160 */
284 const u8 *data; 161 const u8 *data;
285 struct bvec_iter_all iter_all 162 struct bvec_iter_all iter_all = {};
286 struct bio_vec *bvec = bvec_in 163 struct bio_vec *bvec = bvec_init_iter_all(&iter_all);
287 164
288 if (index + 2 > msblk->bytes_u 165 if (index + 2 > msblk->bytes_used) {
289 res = -EIO; 166 res = -EIO;
290 goto out; 167 goto out;
291 } 168 }
292 res = squashfs_bio_read(sb, in 169 res = squashfs_bio_read(sb, index, 2, &bio, &offset);
293 if (res) 170 if (res)
294 goto out; 171 goto out;
295 172
296 if (WARN_ON_ONCE(!bio_next_seg 173 if (WARN_ON_ONCE(!bio_next_segment(bio, &iter_all))) {
297 res = -EIO; 174 res = -EIO;
298 goto out_free_bio; 175 goto out_free_bio;
299 } 176 }
300 /* Extract the length of the m 177 /* Extract the length of the metadata block */
301 data = bvec_virt(bvec); 178 data = bvec_virt(bvec);
302 length = data[offset]; 179 length = data[offset];
303 if (offset < bvec->bv_len - 1) 180 if (offset < bvec->bv_len - 1) {
304 length |= data[offset 181 length |= data[offset + 1] << 8;
305 } else { 182 } else {
306 if (WARN_ON_ONCE(!bio_ 183 if (WARN_ON_ONCE(!bio_next_segment(bio, &iter_all))) {
307 res = -EIO; 184 res = -EIO;
308 goto out_free_ 185 goto out_free_bio;
309 } 186 }
310 data = bvec_virt(bvec) 187 data = bvec_virt(bvec);
311 length |= data[0] << 8 188 length |= data[0] << 8;
312 } 189 }
313 bio_free_pages(bio); 190 bio_free_pages(bio);
314 bio_uninit(bio); 191 bio_uninit(bio);
315 kfree(bio); 192 kfree(bio);
316 193
317 compressed = SQUASHFS_COMPRESS 194 compressed = SQUASHFS_COMPRESSED(length);
318 length = SQUASHFS_COMPRESSED_S 195 length = SQUASHFS_COMPRESSED_SIZE(length);
319 index += 2; 196 index += 2;
320 197
321 TRACE("Block @ 0x%llx, %scompr 198 TRACE("Block @ 0x%llx, %scompressed size %d\n", index - 2,
322 compressed ? "" : "un", 199 compressed ? "" : "un", length);
323 } 200 }
324 if (length <= 0 || length > output->le !! 201 if (length < 0 || length > output->length ||
325 (index + length) > msb 202 (index + length) > msblk->bytes_used) {
326 res = -EIO; 203 res = -EIO;
327 goto out; 204 goto out;
328 } 205 }
329 206
330 if (next_index) 207 if (next_index)
331 *next_index = index + length; 208 *next_index = index + length;
332 209
333 res = squashfs_bio_read(sb, index, len 210 res = squashfs_bio_read(sb, index, length, &bio, &offset);
334 if (res) 211 if (res)
335 goto out; 212 goto out;
336 213
337 if (compressed) { 214 if (compressed) {
338 if (!msblk->stream) { 215 if (!msblk->stream) {
339 res = -EIO; 216 res = -EIO;
340 goto out_free_bio; 217 goto out_free_bio;
341 } 218 }
342 res = msblk->thread_ops->decom 219 res = msblk->thread_ops->decompress(msblk, bio, offset, length, output);
343 } else { 220 } else {
344 res = copy_bio_to_actor(bio, o 221 res = copy_bio_to_actor(bio, output, offset, length);
345 } 222 }
346 223
347 out_free_bio: 224 out_free_bio:
348 bio_free_pages(bio); 225 bio_free_pages(bio);
349 bio_uninit(bio); 226 bio_uninit(bio);
350 kfree(bio); 227 kfree(bio);
351 out: 228 out:
352 if (res < 0) { 229 if (res < 0) {
353 ERROR("Failed to read block 0x 230 ERROR("Failed to read block 0x%llx: %d\n", index, res);
354 if (msblk->panic_on_errors) 231 if (msblk->panic_on_errors)
355 panic("squashfs read f 232 panic("squashfs read failed");
356 } 233 }
357 234
358 return res; 235 return res;
359 } 236 }
360 237
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