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> 20 #include <linux/pagemap.h>
21 #include <linux/string.h> 21 #include <linux/string.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 79 static int squashfs_bio_read_cached(struct bio *fullbio,
80 struct address_space *cache_ma 80 struct address_space *cache_mapping, u64 index, int length,
81 u64 read_start, u64 read_end, 81 u64 read_start, u64 read_end, int page_count)
82 { 82 {
83 struct page *head_to_cache = NULL, *ta 83 struct page *head_to_cache = NULL, *tail_to_cache = NULL;
84 struct block_device *bdev = fullbio->b 84 struct block_device *bdev = fullbio->bi_bdev;
85 int start_idx = 0, end_idx = 0; 85 int start_idx = 0, end_idx = 0;
86 struct bvec_iter_all iter_all; 86 struct bvec_iter_all iter_all;
87 struct bio *bio = NULL; 87 struct bio *bio = NULL;
88 struct bio_vec *bv; 88 struct bio_vec *bv;
89 int idx = 0; 89 int idx = 0;
90 int err = 0; 90 int err = 0;
91 91
92 bio_for_each_segment_all(bv, fullbio, 92 bio_for_each_segment_all(bv, fullbio, iter_all) {
93 struct page *page = bv->bv_pag 93 struct page *page = bv->bv_page;
94 94
95 if (page->mapping == cache_map 95 if (page->mapping == cache_mapping) {
96 idx++; 96 idx++;
97 continue; 97 continue;
98 } 98 }
99 99
100 /* 100 /*
101 * We only use this when the d 101 * We only use this when the device block size is the same as
102 * the page size, so read_star 102 * the page size, so read_start and read_end cover full pages.
103 * 103 *
104 * Compare these to the origin 104 * Compare these to the original required index and length to
105 * only cache pages which were 105 * only cache pages which were requested partially, since these
106 * are the ones which are like 106 * are the ones which are likely to be needed when reading
107 * adjacent blocks. 107 * adjacent blocks.
108 */ 108 */
109 if (idx == 0 && index != read_ 109 if (idx == 0 && index != read_start)
110 head_to_cache = page; 110 head_to_cache = page;
111 else if (idx == page_count - 1 111 else if (idx == page_count - 1 && index + length != read_end)
112 tail_to_cache = page; 112 tail_to_cache = page;
113 113
114 if (!bio || idx != end_idx) { 114 if (!bio || idx != end_idx) {
115 struct bio *new = bio_ 115 struct bio *new = bio_alloc_clone(bdev, fullbio,
116 116 GFP_NOIO, &fs_bio_set);
117 117
118 if (bio) { 118 if (bio) {
119 bio_trim(bio, 119 bio_trim(bio, start_idx * PAGE_SECTORS,
120 (end_ 120 (end_idx - start_idx) * PAGE_SECTORS);
121 bio_chain(bio, 121 bio_chain(bio, new);
122 submit_bio(bio 122 submit_bio(bio);
123 } 123 }
124 124
125 bio = new; 125 bio = new;
126 start_idx = idx; 126 start_idx = idx;
127 } 127 }
128 128
129 idx++; 129 idx++;
130 end_idx = idx; 130 end_idx = idx;
131 } 131 }
132 132
133 if (bio) { 133 if (bio) {
134 bio_trim(bio, start_idx * PAGE 134 bio_trim(bio, start_idx * PAGE_SECTORS,
135 (end_idx - start_idx) 135 (end_idx - start_idx) * PAGE_SECTORS);
136 err = submit_bio_wait(bio); 136 err = submit_bio_wait(bio);
137 bio_put(bio); 137 bio_put(bio);
138 } 138 }
139 139
140 if (err) 140 if (err)
141 return err; 141 return err;
142 142
143 if (head_to_cache) { 143 if (head_to_cache) {
144 int ret = add_to_page_cache_lr 144 int ret = add_to_page_cache_lru(head_to_cache, cache_mapping,
145 145 read_start >> PAGE_SHIFT,
146 146 GFP_NOIO);
147 147
148 if (!ret) { 148 if (!ret) {
149 SetPageUptodate(head_t 149 SetPageUptodate(head_to_cache);
150 unlock_page(head_to_ca 150 unlock_page(head_to_cache);
151 } 151 }
152 152
153 } 153 }
154 154
155 if (tail_to_cache) { 155 if (tail_to_cache) {
156 int ret = add_to_page_cache_lr 156 int ret = add_to_page_cache_lru(tail_to_cache, cache_mapping,
157 157 (read_end >> PAGE_SHIFT) - 1,
158 158 GFP_NOIO);
159 159
160 if (!ret) { 160 if (!ret) {
161 SetPageUptodate(tail_t 161 SetPageUptodate(tail_to_cache);
162 unlock_page(tail_to_ca 162 unlock_page(tail_to_cache);
163 } 163 }
164 } 164 }
165 165
166 return 0; 166 return 0;
167 } 167 }
168 168
169 static struct page *squashfs_get_cache_page(st 169 static struct page *squashfs_get_cache_page(struct address_space *mapping,
170 pg 170 pgoff_t index)
171 { 171 {
172 struct page *page; 172 struct page *page;
173 173
174 if (!mapping) 174 if (!mapping)
175 return NULL; 175 return NULL;
176 176
177 page = find_get_page(mapping, index); 177 page = find_get_page(mapping, index);
178 if (!page) 178 if (!page)
179 return NULL; 179 return NULL;
180 180
181 if (!PageUptodate(page)) { 181 if (!PageUptodate(page)) {
182 put_page(page); 182 put_page(page);
183 return NULL; 183 return NULL;
184 } 184 }
185 185
186 return page; 186 return page;
187 } 187 }
188 188
189 static int squashfs_bio_read(struct super_bloc 189 static int squashfs_bio_read(struct super_block *sb, u64 index, int length,
190 struct bio **biop 190 struct bio **biop, int *block_offset)
191 { 191 {
192 struct squashfs_sb_info *msblk = sb->s 192 struct squashfs_sb_info *msblk = sb->s_fs_info;
193 struct address_space *cache_mapping = 193 struct address_space *cache_mapping = msblk->cache_mapping;
194 const u64 read_start = round_down(inde 194 const u64 read_start = round_down(index, msblk->devblksize);
195 const sector_t block = read_start >> m 195 const sector_t block = read_start >> msblk->devblksize_log2;
196 const u64 read_end = round_up(index + 196 const u64 read_end = round_up(index + length, msblk->devblksize);
197 const sector_t block_end = read_end >> 197 const sector_t block_end = read_end >> msblk->devblksize_log2;
198 int offset = read_start - round_down(i 198 int offset = read_start - round_down(index, PAGE_SIZE);
199 int total_len = (block_end - block) << 199 int total_len = (block_end - block) << msblk->devblksize_log2;
200 const int page_count = DIV_ROUND_UP(to 200 const int page_count = DIV_ROUND_UP(total_len + offset, PAGE_SIZE);
201 int error, i; 201 int error, i;
202 struct bio *bio; 202 struct bio *bio;
203 203
204 bio = bio_kmalloc(page_count, GFP_NOIO 204 bio = bio_kmalloc(page_count, GFP_NOIO);
205 if (!bio) 205 if (!bio)
206 return -ENOMEM; 206 return -ENOMEM;
207 bio_init(bio, sb->s_bdev, bio->bi_inli 207 bio_init(bio, sb->s_bdev, bio->bi_inline_vecs, page_count, REQ_OP_READ);
208 bio->bi_iter.bi_sector = block * (msbl 208 bio->bi_iter.bi_sector = block * (msblk->devblksize >> SECTOR_SHIFT);
209 209
210 for (i = 0; i < page_count; ++i) { 210 for (i = 0; i < page_count; ++i) {
211 unsigned int len = 211 unsigned int len =
212 min_t(unsigned int, PA 212 min_t(unsigned int, PAGE_SIZE - offset, total_len);
213 pgoff_t index = (read_start >> 213 pgoff_t index = (read_start >> PAGE_SHIFT) + i;
214 struct page *page; 214 struct page *page;
215 215
216 page = squashfs_get_cache_page 216 page = squashfs_get_cache_page(cache_mapping, index);
217 if (!page) 217 if (!page)
218 page = alloc_page(GFP_ 218 page = alloc_page(GFP_NOIO);
219 219
220 if (!page) { 220 if (!page) {
221 error = -ENOMEM; 221 error = -ENOMEM;
222 goto out_free_bio; 222 goto out_free_bio;
223 } 223 }
224 224
225 /* 225 /*
226 * Use the __ version to avoid 226 * Use the __ version to avoid merging since we need each page
227 * to be separate when we chec 227 * to be separate when we check for and avoid cached pages.
228 */ 228 */
229 __bio_add_page(bio, page, len, 229 __bio_add_page(bio, page, len, offset);
230 offset = 0; 230 offset = 0;
231 total_len -= len; 231 total_len -= len;
232 } 232 }
233 233
234 if (cache_mapping) 234 if (cache_mapping)
235 error = squashfs_bio_read_cach 235 error = squashfs_bio_read_cached(bio, cache_mapping, index,
236 236 length, read_start, read_end,
237 237 page_count);
238 else 238 else
239 error = submit_bio_wait(bio); 239 error = submit_bio_wait(bio);
240 if (error) 240 if (error)
241 goto out_free_bio; 241 goto out_free_bio;
242 242
243 *biop = bio; 243 *biop = bio;
244 *block_offset = index & ((1 << msblk-> 244 *block_offset = index & ((1 << msblk->devblksize_log2) - 1);
245 return 0; 245 return 0;
246 246
247 out_free_bio: 247 out_free_bio:
248 bio_free_pages(bio); 248 bio_free_pages(bio);
249 bio_uninit(bio); 249 bio_uninit(bio);
250 kfree(bio); 250 kfree(bio);
251 return error; 251 return error;
252 } 252 }
253 253
254 /* 254 /*
255 * Read and decompress a metadata block or dat 255 * Read and decompress a metadata block or datablock. Length is non-zero
256 * if a datablock is being read (the size is s 256 * if a datablock is being read (the size is stored elsewhere in the
257 * filesystem), otherwise the length is obtain 257 * filesystem), otherwise the length is obtained from the first two bytes of
258 * the metadata block. A bit in the length fi 258 * the metadata block. A bit in the length field indicates if the block
259 * is stored uncompressed in the filesystem (u 259 * is stored uncompressed in the filesystem (usually because compression
260 * generated a larger block - this does occasi 260 * generated a larger block - this does occasionally happen with compression
261 * algorithms). 261 * algorithms).
262 */ 262 */
263 int squashfs_read_data(struct super_block *sb, 263 int squashfs_read_data(struct super_block *sb, u64 index, int length,
264 u64 *next_index, struct 264 u64 *next_index, struct squashfs_page_actor *output)
265 { 265 {
266 struct squashfs_sb_info *msblk = sb->s 266 struct squashfs_sb_info *msblk = sb->s_fs_info;
267 struct bio *bio = NULL; 267 struct bio *bio = NULL;
268 int compressed; 268 int compressed;
269 int res; 269 int res;
270 int offset; 270 int offset;
271 271
272 if (length) { 272 if (length) {
273 /* 273 /*
274 * Datablock. 274 * Datablock.
275 */ 275 */
276 compressed = SQUASHFS_COMPRESS 276 compressed = SQUASHFS_COMPRESSED_BLOCK(length);
277 length = SQUASHFS_COMPRESSED_S 277 length = SQUASHFS_COMPRESSED_SIZE_BLOCK(length);
278 TRACE("Block @ 0x%llx, %scompr 278 TRACE("Block @ 0x%llx, %scompressed size %d, src size %d\n",
279 index, compressed ? "" 279 index, compressed ? "" : "un", length, output->length);
280 } else { 280 } else {
281 /* 281 /*
282 * Metadata block. 282 * Metadata block.
283 */ 283 */
284 const u8 *data; 284 const u8 *data;
285 struct bvec_iter_all iter_all 285 struct bvec_iter_all iter_all = {};
286 struct bio_vec *bvec = bvec_in 286 struct bio_vec *bvec = bvec_init_iter_all(&iter_all);
287 287
288 if (index + 2 > msblk->bytes_u 288 if (index + 2 > msblk->bytes_used) {
289 res = -EIO; 289 res = -EIO;
290 goto out; 290 goto out;
291 } 291 }
292 res = squashfs_bio_read(sb, in 292 res = squashfs_bio_read(sb, index, 2, &bio, &offset);
293 if (res) 293 if (res)
294 goto out; 294 goto out;
295 295
296 if (WARN_ON_ONCE(!bio_next_seg 296 if (WARN_ON_ONCE(!bio_next_segment(bio, &iter_all))) {
297 res = -EIO; 297 res = -EIO;
298 goto out_free_bio; 298 goto out_free_bio;
299 } 299 }
300 /* Extract the length of the m 300 /* Extract the length of the metadata block */
301 data = bvec_virt(bvec); 301 data = bvec_virt(bvec);
302 length = data[offset]; 302 length = data[offset];
303 if (offset < bvec->bv_len - 1) 303 if (offset < bvec->bv_len - 1) {
304 length |= data[offset 304 length |= data[offset + 1] << 8;
305 } else { 305 } else {
306 if (WARN_ON_ONCE(!bio_ 306 if (WARN_ON_ONCE(!bio_next_segment(bio, &iter_all))) {
307 res = -EIO; 307 res = -EIO;
308 goto out_free_ 308 goto out_free_bio;
309 } 309 }
310 data = bvec_virt(bvec) 310 data = bvec_virt(bvec);
311 length |= data[0] << 8 311 length |= data[0] << 8;
312 } 312 }
313 bio_free_pages(bio); 313 bio_free_pages(bio);
314 bio_uninit(bio); 314 bio_uninit(bio);
315 kfree(bio); 315 kfree(bio);
316 316
317 compressed = SQUASHFS_COMPRESS 317 compressed = SQUASHFS_COMPRESSED(length);
318 length = SQUASHFS_COMPRESSED_S 318 length = SQUASHFS_COMPRESSED_SIZE(length);
319 index += 2; 319 index += 2;
320 320
321 TRACE("Block @ 0x%llx, %scompr 321 TRACE("Block @ 0x%llx, %scompressed size %d\n", index - 2,
322 compressed ? "" : "un", 322 compressed ? "" : "un", length);
323 } 323 }
324 if (length <= 0 || length > output->le 324 if (length <= 0 || length > output->length ||
325 (index + length) > msb 325 (index + length) > msblk->bytes_used) {
326 res = -EIO; 326 res = -EIO;
327 goto out; 327 goto out;
328 } 328 }
329 329
330 if (next_index) 330 if (next_index)
331 *next_index = index + length; 331 *next_index = index + length;
332 332
333 res = squashfs_bio_read(sb, index, len 333 res = squashfs_bio_read(sb, index, length, &bio, &offset);
334 if (res) 334 if (res)
335 goto out; 335 goto out;
336 336
337 if (compressed) { 337 if (compressed) {
338 if (!msblk->stream) { 338 if (!msblk->stream) {
339 res = -EIO; 339 res = -EIO;
340 goto out_free_bio; 340 goto out_free_bio;
341 } 341 }
342 res = msblk->thread_ops->decom 342 res = msblk->thread_ops->decompress(msblk, bio, offset, length, output);
343 } else { 343 } else {
344 res = copy_bio_to_actor(bio, o 344 res = copy_bio_to_actor(bio, output, offset, length);
345 } 345 }
346 346
347 out_free_bio: 347 out_free_bio:
348 bio_free_pages(bio); 348 bio_free_pages(bio);
349 bio_uninit(bio); 349 bio_uninit(bio);
350 kfree(bio); 350 kfree(bio);
351 out: 351 out:
352 if (res < 0) { 352 if (res < 0) {
353 ERROR("Failed to read block 0x 353 ERROR("Failed to read block 0x%llx: %d\n", index, res);
354 if (msblk->panic_on_errors) 354 if (msblk->panic_on_errors)
355 panic("squashfs read f 355 panic("squashfs read failed");
356 } 356 }
357 357
358 return res; 358 return res;
359 } 359 }
360 360
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