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02e83f46 DW |
1 | // SPDX-License-Identifier: GPL-2.0-only |
2 | #include <linux/slab.h> | |
3 | #include <linux/stat.h> | |
4 | #include <linux/sched/xacct.h> | |
5 | #include <linux/fcntl.h> | |
6 | #include <linux/file.h> | |
7 | #include <linux/uio.h> | |
8 | #include <linux/fsnotify.h> | |
9 | #include <linux/security.h> | |
10 | #include <linux/export.h> | |
11 | #include <linux/syscalls.h> | |
12 | #include <linux/pagemap.h> | |
13 | #include <linux/splice.h> | |
14 | #include <linux/compat.h> | |
15 | #include <linux/mount.h> | |
16 | #include <linux/fs.h> | |
17 | #include "internal.h" | |
18 | ||
19 | #include <linux/uaccess.h> | |
20 | #include <asm/unistd.h> | |
21 | ||
22 | /* | |
23 | * Performs necessary checks before doing a clone. | |
24 | * | |
25 | * Can adjust amount of bytes to clone via @req_count argument. | |
26 | * Returns appropriate error code that caller should return or | |
27 | * zero in case the clone should be allowed. | |
28 | */ | |
1b2c54d6 DW |
29 | static int generic_remap_checks(struct file *file_in, loff_t pos_in, |
30 | struct file *file_out, loff_t pos_out, | |
31 | loff_t *req_count, unsigned int remap_flags) | |
02e83f46 DW |
32 | { |
33 | struct inode *inode_in = file_in->f_mapping->host; | |
34 | struct inode *inode_out = file_out->f_mapping->host; | |
35 | uint64_t count = *req_count; | |
36 | uint64_t bcount; | |
37 | loff_t size_in, size_out; | |
38 | loff_t bs = inode_out->i_sb->s_blocksize; | |
39 | int ret; | |
40 | ||
41 | /* The start of both ranges must be aligned to an fs block. */ | |
42 | if (!IS_ALIGNED(pos_in, bs) || !IS_ALIGNED(pos_out, bs)) | |
43 | return -EINVAL; | |
44 | ||
45 | /* Ensure offsets don't wrap. */ | |
46 | if (pos_in + count < pos_in || pos_out + count < pos_out) | |
47 | return -EINVAL; | |
48 | ||
49 | size_in = i_size_read(inode_in); | |
50 | size_out = i_size_read(inode_out); | |
51 | ||
52 | /* Dedupe requires both ranges to be within EOF. */ | |
53 | if ((remap_flags & REMAP_FILE_DEDUP) && | |
54 | (pos_in >= size_in || pos_in + count > size_in || | |
55 | pos_out >= size_out || pos_out + count > size_out)) | |
56 | return -EINVAL; | |
57 | ||
58 | /* Ensure the infile range is within the infile. */ | |
59 | if (pos_in >= size_in) | |
60 | return -EINVAL; | |
61 | count = min(count, size_in - (uint64_t)pos_in); | |
62 | ||
63 | ret = generic_write_check_limits(file_out, pos_out, &count); | |
64 | if (ret) | |
65 | return ret; | |
66 | ||
67 | /* | |
68 | * If the user wanted us to link to the infile's EOF, round up to the | |
69 | * next block boundary for this check. | |
70 | * | |
71 | * Otherwise, make sure the count is also block-aligned, having | |
72 | * already confirmed the starting offsets' block alignment. | |
73 | */ | |
74 | if (pos_in + count == size_in) { | |
75 | bcount = ALIGN(size_in, bs) - pos_in; | |
76 | } else { | |
77 | if (!IS_ALIGNED(count, bs)) | |
78 | count = ALIGN_DOWN(count, bs); | |
79 | bcount = count; | |
80 | } | |
81 | ||
82 | /* Don't allow overlapped cloning within the same file. */ | |
83 | if (inode_in == inode_out && | |
84 | pos_out + bcount > pos_in && | |
85 | pos_out < pos_in + bcount) | |
86 | return -EINVAL; | |
87 | ||
88 | /* | |
89 | * We shortened the request but the caller can't deal with that, so | |
90 | * bounce the request back to userspace. | |
91 | */ | |
92 | if (*req_count != count && !(remap_flags & REMAP_FILE_CAN_SHORTEN)) | |
93 | return -EINVAL; | |
94 | ||
95 | *req_count = count; | |
96 | return 0; | |
97 | } | |
1b2c54d6 DW |
98 | |
99 | static int remap_verify_area(struct file *file, loff_t pos, loff_t len, | |
100 | bool write) | |
101 | { | |
1b2c54d6 DW |
102 | if (unlikely(pos < 0 || len < 0)) |
103 | return -EINVAL; | |
104 | ||
105 | if (unlikely((loff_t) (pos + len) < 0)) | |
106 | return -EINVAL; | |
107 | ||
1b2c54d6 DW |
108 | return security_file_permission(file, write ? MAY_WRITE : MAY_READ); |
109 | } | |
110 | ||
111 | /* | |
112 | * Ensure that we don't remap a partial EOF block in the middle of something | |
113 | * else. Assume that the offsets have already been checked for block | |
114 | * alignment. | |
115 | * | |
116 | * For clone we only link a partial EOF block above or at the destination file's | |
117 | * EOF. For deduplication we accept a partial EOF block only if it ends at the | |
118 | * destination file's EOF (can not link it into the middle of a file). | |
119 | * | |
120 | * Shorten the request if possible. | |
121 | */ | |
122 | static int generic_remap_check_len(struct inode *inode_in, | |
123 | struct inode *inode_out, | |
124 | loff_t pos_out, | |
125 | loff_t *len, | |
126 | unsigned int remap_flags) | |
127 | { | |
128 | u64 blkmask = i_blocksize(inode_in) - 1; | |
129 | loff_t new_len = *len; | |
130 | ||
131 | if ((*len & blkmask) == 0) | |
132 | return 0; | |
133 | ||
134 | if (pos_out + *len < i_size_read(inode_out)) | |
135 | new_len &= ~blkmask; | |
136 | ||
137 | if (new_len == *len) | |
138 | return 0; | |
139 | ||
140 | if (remap_flags & REMAP_FILE_CAN_SHORTEN) { | |
141 | *len = new_len; | |
142 | return 0; | |
143 | } | |
144 | ||
145 | return (remap_flags & REMAP_FILE_DEDUP) ? -EBADE : -EINVAL; | |
146 | } | |
147 | ||
148 | /* Read a page's worth of file data into the page cache. */ | |
149 | static struct page *vfs_dedupe_get_page(struct inode *inode, loff_t offset) | |
150 | { | |
151 | struct page *page; | |
152 | ||
153 | page = read_mapping_page(inode->i_mapping, offset >> PAGE_SHIFT, NULL); | |
154 | if (IS_ERR(page)) | |
155 | return page; | |
156 | if (!PageUptodate(page)) { | |
157 | put_page(page); | |
158 | return ERR_PTR(-EIO); | |
159 | } | |
160 | return page; | |
161 | } | |
162 | ||
163 | /* | |
164 | * Lock two pages, ensuring that we lock in offset order if the pages are from | |
165 | * the same file. | |
166 | */ | |
167 | static void vfs_lock_two_pages(struct page *page1, struct page *page2) | |
168 | { | |
169 | /* Always lock in order of increasing index. */ | |
170 | if (page1->index > page2->index) | |
171 | swap(page1, page2); | |
172 | ||
173 | lock_page(page1); | |
174 | if (page1 != page2) | |
175 | lock_page(page2); | |
176 | } | |
177 | ||
178 | /* Unlock two pages, being careful not to unlock the same page twice. */ | |
179 | static void vfs_unlock_two_pages(struct page *page1, struct page *page2) | |
180 | { | |
181 | unlock_page(page1); | |
182 | if (page1 != page2) | |
183 | unlock_page(page2); | |
184 | } | |
185 | ||
186 | /* | |
187 | * Compare extents of two files to see if they are the same. | |
188 | * Caller must have locked both inodes to prevent write races. | |
189 | */ | |
190 | static int vfs_dedupe_file_range_compare(struct inode *src, loff_t srcoff, | |
191 | struct inode *dest, loff_t destoff, | |
192 | loff_t len, bool *is_same) | |
193 | { | |
194 | loff_t src_poff; | |
195 | loff_t dest_poff; | |
196 | void *src_addr; | |
197 | void *dest_addr; | |
198 | struct page *src_page; | |
199 | struct page *dest_page; | |
200 | loff_t cmp_len; | |
201 | bool same; | |
202 | int error; | |
203 | ||
204 | error = -EINVAL; | |
205 | same = true; | |
206 | while (len) { | |
207 | src_poff = srcoff & (PAGE_SIZE - 1); | |
208 | dest_poff = destoff & (PAGE_SIZE - 1); | |
209 | cmp_len = min(PAGE_SIZE - src_poff, | |
210 | PAGE_SIZE - dest_poff); | |
211 | cmp_len = min(cmp_len, len); | |
212 | if (cmp_len <= 0) | |
213 | goto out_error; | |
214 | ||
215 | src_page = vfs_dedupe_get_page(src, srcoff); | |
216 | if (IS_ERR(src_page)) { | |
217 | error = PTR_ERR(src_page); | |
218 | goto out_error; | |
219 | } | |
220 | dest_page = vfs_dedupe_get_page(dest, destoff); | |
221 | if (IS_ERR(dest_page)) { | |
222 | error = PTR_ERR(dest_page); | |
223 | put_page(src_page); | |
224 | goto out_error; | |
225 | } | |
226 | ||
227 | vfs_lock_two_pages(src_page, dest_page); | |
228 | ||
229 | /* | |
230 | * Now that we've locked both pages, make sure they're still | |
231 | * mapped to the file data we're interested in. If not, | |
232 | * someone is invalidating pages on us and we lose. | |
233 | */ | |
234 | if (!PageUptodate(src_page) || !PageUptodate(dest_page) || | |
235 | src_page->mapping != src->i_mapping || | |
236 | dest_page->mapping != dest->i_mapping) { | |
237 | same = false; | |
238 | goto unlock; | |
239 | } | |
240 | ||
241 | src_addr = kmap_atomic(src_page); | |
242 | dest_addr = kmap_atomic(dest_page); | |
243 | ||
244 | flush_dcache_page(src_page); | |
245 | flush_dcache_page(dest_page); | |
246 | ||
247 | if (memcmp(src_addr + src_poff, dest_addr + dest_poff, cmp_len)) | |
248 | same = false; | |
249 | ||
250 | kunmap_atomic(dest_addr); | |
251 | kunmap_atomic(src_addr); | |
252 | unlock: | |
253 | vfs_unlock_two_pages(src_page, dest_page); | |
254 | put_page(dest_page); | |
255 | put_page(src_page); | |
256 | ||
257 | if (!same) | |
258 | break; | |
259 | ||
260 | srcoff += cmp_len; | |
261 | destoff += cmp_len; | |
262 | len -= cmp_len; | |
263 | } | |
264 | ||
265 | *is_same = same; | |
266 | return 0; | |
267 | ||
268 | out_error: | |
269 | return error; | |
270 | } | |
271 | ||
272 | /* | |
273 | * Check that the two inodes are eligible for cloning, the ranges make | |
274 | * sense, and then flush all dirty data. Caller must ensure that the | |
275 | * inodes have been locked against any other modifications. | |
276 | * | |
277 | * If there's an error, then the usual negative error code is returned. | |
278 | * Otherwise returns 0 with *len set to the request length. | |
279 | */ | |
280 | int generic_remap_file_range_prep(struct file *file_in, loff_t pos_in, | |
281 | struct file *file_out, loff_t pos_out, | |
282 | loff_t *len, unsigned int remap_flags) | |
283 | { | |
284 | struct inode *inode_in = file_inode(file_in); | |
285 | struct inode *inode_out = file_inode(file_out); | |
286 | bool same_inode = (inode_in == inode_out); | |
287 | int ret; | |
288 | ||
289 | /* Don't touch certain kinds of inodes */ | |
290 | if (IS_IMMUTABLE(inode_out)) | |
291 | return -EPERM; | |
292 | ||
293 | if (IS_SWAPFILE(inode_in) || IS_SWAPFILE(inode_out)) | |
294 | return -ETXTBSY; | |
295 | ||
296 | /* Don't reflink dirs, pipes, sockets... */ | |
297 | if (S_ISDIR(inode_in->i_mode) || S_ISDIR(inode_out->i_mode)) | |
298 | return -EISDIR; | |
299 | if (!S_ISREG(inode_in->i_mode) || !S_ISREG(inode_out->i_mode)) | |
300 | return -EINVAL; | |
301 | ||
302 | /* Zero length dedupe exits immediately; reflink goes to EOF. */ | |
303 | if (*len == 0) { | |
304 | loff_t isize = i_size_read(inode_in); | |
305 | ||
306 | if ((remap_flags & REMAP_FILE_DEDUP) || pos_in == isize) | |
307 | return 0; | |
308 | if (pos_in > isize) | |
309 | return -EINVAL; | |
310 | *len = isize - pos_in; | |
311 | if (*len == 0) | |
312 | return 0; | |
313 | } | |
314 | ||
315 | /* Check that we don't violate system file offset limits. */ | |
316 | ret = generic_remap_checks(file_in, pos_in, file_out, pos_out, len, | |
317 | remap_flags); | |
318 | if (ret) | |
319 | return ret; | |
320 | ||
321 | /* Wait for the completion of any pending IOs on both files */ | |
322 | inode_dio_wait(inode_in); | |
323 | if (!same_inode) | |
324 | inode_dio_wait(inode_out); | |
325 | ||
326 | ret = filemap_write_and_wait_range(inode_in->i_mapping, | |
327 | pos_in, pos_in + *len - 1); | |
328 | if (ret) | |
329 | return ret; | |
330 | ||
331 | ret = filemap_write_and_wait_range(inode_out->i_mapping, | |
332 | pos_out, pos_out + *len - 1); | |
333 | if (ret) | |
334 | return ret; | |
335 | ||
336 | /* | |
337 | * Check that the extents are the same. | |
338 | */ | |
339 | if (remap_flags & REMAP_FILE_DEDUP) { | |
340 | bool is_same = false; | |
341 | ||
342 | ret = vfs_dedupe_file_range_compare(inode_in, pos_in, | |
343 | inode_out, pos_out, *len, &is_same); | |
344 | if (ret) | |
345 | return ret; | |
346 | if (!is_same) | |
347 | return -EBADE; | |
348 | } | |
349 | ||
350 | ret = generic_remap_check_len(inode_in, inode_out, pos_out, len, | |
351 | remap_flags); | |
352 | if (ret) | |
353 | return ret; | |
354 | ||
355 | /* If can't alter the file contents, we're done. */ | |
356 | if (!(remap_flags & REMAP_FILE_DEDUP)) | |
357 | ret = file_modified(file_out); | |
358 | ||
359 | return ret; | |
360 | } | |
361 | EXPORT_SYMBOL(generic_remap_file_range_prep); | |
362 | ||
363 | loff_t do_clone_file_range(struct file *file_in, loff_t pos_in, | |
364 | struct file *file_out, loff_t pos_out, | |
365 | loff_t len, unsigned int remap_flags) | |
366 | { | |
367 | loff_t ret; | |
368 | ||
369 | WARN_ON_ONCE(remap_flags & REMAP_FILE_DEDUP); | |
370 | ||
371 | /* | |
372 | * FICLONE/FICLONERANGE ioctls enforce that src and dest files are on | |
373 | * the same mount. Practically, they only need to be on the same file | |
374 | * system. | |
375 | */ | |
376 | if (file_inode(file_in)->i_sb != file_inode(file_out)->i_sb) | |
377 | return -EXDEV; | |
378 | ||
379 | ret = generic_file_rw_checks(file_in, file_out); | |
380 | if (ret < 0) | |
381 | return ret; | |
382 | ||
383 | if (!file_in->f_op->remap_file_range) | |
384 | return -EOPNOTSUPP; | |
385 | ||
386 | ret = remap_verify_area(file_in, pos_in, len, false); | |
387 | if (ret) | |
388 | return ret; | |
389 | ||
390 | ret = remap_verify_area(file_out, pos_out, len, true); | |
391 | if (ret) | |
392 | return ret; | |
393 | ||
394 | ret = file_in->f_op->remap_file_range(file_in, pos_in, | |
395 | file_out, pos_out, len, remap_flags); | |
396 | if (ret < 0) | |
397 | return ret; | |
398 | ||
399 | fsnotify_access(file_in); | |
400 | fsnotify_modify(file_out); | |
401 | return ret; | |
402 | } | |
403 | EXPORT_SYMBOL(do_clone_file_range); | |
404 | ||
405 | loff_t vfs_clone_file_range(struct file *file_in, loff_t pos_in, | |
406 | struct file *file_out, loff_t pos_out, | |
407 | loff_t len, unsigned int remap_flags) | |
408 | { | |
409 | loff_t ret; | |
410 | ||
411 | file_start_write(file_out); | |
412 | ret = do_clone_file_range(file_in, pos_in, file_out, pos_out, len, | |
413 | remap_flags); | |
414 | file_end_write(file_out); | |
415 | ||
416 | return ret; | |
417 | } | |
418 | EXPORT_SYMBOL(vfs_clone_file_range); | |
419 | ||
420 | /* Check whether we are allowed to dedupe the destination file */ | |
421 | static bool allow_file_dedupe(struct file *file) | |
422 | { | |
0f5d220b CB |
423 | struct user_namespace *mnt_userns = file_mnt_user_ns(file); |
424 | struct inode *inode = file_inode(file); | |
425 | ||
1b2c54d6 DW |
426 | if (capable(CAP_SYS_ADMIN)) |
427 | return true; | |
428 | if (file->f_mode & FMODE_WRITE) | |
429 | return true; | |
0f5d220b | 430 | if (uid_eq(current_fsuid(), i_uid_into_mnt(mnt_userns, inode))) |
1b2c54d6 | 431 | return true; |
0f5d220b | 432 | if (!inode_permission(mnt_userns, inode, MAY_WRITE)) |
1b2c54d6 DW |
433 | return true; |
434 | return false; | |
435 | } | |
436 | ||
437 | loff_t vfs_dedupe_file_range_one(struct file *src_file, loff_t src_pos, | |
438 | struct file *dst_file, loff_t dst_pos, | |
439 | loff_t len, unsigned int remap_flags) | |
440 | { | |
441 | loff_t ret; | |
442 | ||
443 | WARN_ON_ONCE(remap_flags & ~(REMAP_FILE_DEDUP | | |
444 | REMAP_FILE_CAN_SHORTEN)); | |
445 | ||
446 | ret = mnt_want_write_file(dst_file); | |
447 | if (ret) | |
448 | return ret; | |
449 | ||
3078d85c MS |
450 | /* |
451 | * This is redundant if called from vfs_dedupe_file_range(), but other | |
452 | * callers need it and it's not performance sesitive... | |
453 | */ | |
454 | ret = remap_verify_area(src_file, src_pos, len, false); | |
455 | if (ret) | |
456 | goto out_drop_write; | |
457 | ||
1b2c54d6 | 458 | ret = remap_verify_area(dst_file, dst_pos, len, true); |
3078d85c | 459 | if (ret) |
1b2c54d6 DW |
460 | goto out_drop_write; |
461 | ||
462 | ret = -EPERM; | |
463 | if (!allow_file_dedupe(dst_file)) | |
464 | goto out_drop_write; | |
465 | ||
466 | ret = -EXDEV; | |
467 | if (src_file->f_path.mnt != dst_file->f_path.mnt) | |
468 | goto out_drop_write; | |
469 | ||
470 | ret = -EISDIR; | |
471 | if (S_ISDIR(file_inode(dst_file)->i_mode)) | |
472 | goto out_drop_write; | |
473 | ||
474 | ret = -EINVAL; | |
475 | if (!dst_file->f_op->remap_file_range) | |
476 | goto out_drop_write; | |
477 | ||
478 | if (len == 0) { | |
479 | ret = 0; | |
480 | goto out_drop_write; | |
481 | } | |
482 | ||
483 | ret = dst_file->f_op->remap_file_range(src_file, src_pos, dst_file, | |
484 | dst_pos, len, remap_flags | REMAP_FILE_DEDUP); | |
485 | out_drop_write: | |
486 | mnt_drop_write_file(dst_file); | |
487 | ||
488 | return ret; | |
489 | } | |
490 | EXPORT_SYMBOL(vfs_dedupe_file_range_one); | |
491 | ||
492 | int vfs_dedupe_file_range(struct file *file, struct file_dedupe_range *same) | |
493 | { | |
494 | struct file_dedupe_range_info *info; | |
495 | struct inode *src = file_inode(file); | |
496 | u64 off; | |
497 | u64 len; | |
498 | int i; | |
499 | int ret; | |
500 | u16 count = same->dest_count; | |
501 | loff_t deduped; | |
502 | ||
503 | if (!(file->f_mode & FMODE_READ)) | |
504 | return -EINVAL; | |
505 | ||
506 | if (same->reserved1 || same->reserved2) | |
507 | return -EINVAL; | |
508 | ||
509 | off = same->src_offset; | |
510 | len = same->src_length; | |
511 | ||
512 | if (S_ISDIR(src->i_mode)) | |
513 | return -EISDIR; | |
514 | ||
515 | if (!S_ISREG(src->i_mode)) | |
516 | return -EINVAL; | |
517 | ||
518 | if (!file->f_op->remap_file_range) | |
519 | return -EOPNOTSUPP; | |
520 | ||
521 | ret = remap_verify_area(file, off, len, false); | |
522 | if (ret < 0) | |
523 | return ret; | |
524 | ret = 0; | |
525 | ||
526 | if (off + len > i_size_read(src)) | |
527 | return -EINVAL; | |
528 | ||
529 | /* Arbitrary 1G limit on a single dedupe request, can be raised. */ | |
530 | len = min_t(u64, len, 1 << 30); | |
531 | ||
532 | /* pre-format output fields to sane values */ | |
533 | for (i = 0; i < count; i++) { | |
534 | same->info[i].bytes_deduped = 0ULL; | |
535 | same->info[i].status = FILE_DEDUPE_RANGE_SAME; | |
536 | } | |
537 | ||
538 | for (i = 0, info = same->info; i < count; i++, info++) { | |
539 | struct fd dst_fd = fdget(info->dest_fd); | |
540 | struct file *dst_file = dst_fd.file; | |
541 | ||
542 | if (!dst_file) { | |
543 | info->status = -EBADF; | |
544 | goto next_loop; | |
545 | } | |
546 | ||
547 | if (info->reserved) { | |
548 | info->status = -EINVAL; | |
549 | goto next_fdput; | |
550 | } | |
551 | ||
552 | deduped = vfs_dedupe_file_range_one(file, off, dst_file, | |
553 | info->dest_offset, len, | |
554 | REMAP_FILE_CAN_SHORTEN); | |
555 | if (deduped == -EBADE) | |
556 | info->status = FILE_DEDUPE_RANGE_DIFFERS; | |
557 | else if (deduped < 0) | |
558 | info->status = deduped; | |
559 | else | |
560 | info->bytes_deduped = len; | |
561 | ||
562 | next_fdput: | |
563 | fdput(dst_fd); | |
564 | next_loop: | |
565 | if (fatal_signal_pending(current)) | |
566 | break; | |
567 | } | |
568 | return ret; | |
569 | } | |
570 | EXPORT_SYMBOL(vfs_dedupe_file_range); |