Line data Source code
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 : */
29 0 : 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)
32 : {
33 0 : struct inode *inode_in = file_in->f_mapping->host;
34 0 : struct inode *inode_out = file_out->f_mapping->host;
35 0 : uint64_t count = *req_count;
36 0 : uint64_t bcount;
37 0 : loff_t size_in, size_out;
38 0 : loff_t bs = inode_out->i_sb->s_blocksize;
39 0 : int ret;
40 :
41 : /* The start of both ranges must be aligned to an fs block. */
42 0 : if (!IS_ALIGNED(pos_in, bs) || !IS_ALIGNED(pos_out, bs))
43 : return -EINVAL;
44 :
45 : /* Ensure offsets don't wrap. */
46 0 : if (pos_in + count < pos_in || pos_out + count < pos_out)
47 : return -EINVAL;
48 :
49 0 : size_in = i_size_read(inode_in);
50 0 : size_out = i_size_read(inode_out);
51 :
52 : /* Dedupe requires both ranges to be within EOF. */
53 0 : if ((remap_flags & REMAP_FILE_DEDUP) &&
54 0 : (pos_in >= size_in || pos_in + count > size_in ||
55 0 : pos_out >= size_out || pos_out + count > size_out))
56 : return -EINVAL;
57 :
58 : /* Ensure the infile range is within the infile. */
59 0 : if (pos_in >= size_in)
60 : return -EINVAL;
61 0 : count = min(count, size_in - (uint64_t)pos_in);
62 :
63 0 : ret = generic_write_check_limits(file_out, pos_out, &count);
64 0 : 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 0 : if (pos_in + count == size_in) {
75 0 : bcount = ALIGN(size_in, bs) - pos_in;
76 : } else {
77 0 : if (!IS_ALIGNED(count, bs))
78 0 : count = ALIGN_DOWN(count, bs);
79 0 : bcount = count;
80 : }
81 :
82 : /* Don't allow overlapped cloning within the same file. */
83 0 : if (inode_in == inode_out &&
84 0 : pos_out + bcount > pos_in &&
85 0 : 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 0 : if (*req_count != count && !(remap_flags & REMAP_FILE_CAN_SHORTEN))
93 : return -EINVAL;
94 :
95 0 : *req_count = count;
96 0 : return 0;
97 : }
98 :
99 0 : static int remap_verify_area(struct file *file, loff_t pos, loff_t len,
100 : bool write)
101 : {
102 0 : struct inode *inode = file_inode(file);
103 :
104 0 : if (unlikely(pos < 0 || len < 0))
105 : return -EINVAL;
106 :
107 0 : if (unlikely((loff_t) (pos + len) < 0))
108 : return -EINVAL;
109 :
110 0 : if (unlikely(inode->i_flctx && mandatory_lock(inode))) {
111 : loff_t end = len ? pos + len - 1 : OFFSET_MAX;
112 : int retval;
113 :
114 : retval = locks_mandatory_area(inode, file, pos, end,
115 : write ? F_WRLCK : F_RDLCK);
116 : if (retval < 0)
117 : return retval;
118 : }
119 :
120 0 : return security_file_permission(file, write ? MAY_WRITE : MAY_READ);
121 : }
122 :
123 : /*
124 : * Ensure that we don't remap a partial EOF block in the middle of something
125 : * else. Assume that the offsets have already been checked for block
126 : * alignment.
127 : *
128 : * For clone we only link a partial EOF block above or at the destination file's
129 : * EOF. For deduplication we accept a partial EOF block only if it ends at the
130 : * destination file's EOF (can not link it into the middle of a file).
131 : *
132 : * Shorten the request if possible.
133 : */
134 0 : static int generic_remap_check_len(struct inode *inode_in,
135 : struct inode *inode_out,
136 : loff_t pos_out,
137 : loff_t *len,
138 : unsigned int remap_flags)
139 : {
140 0 : u64 blkmask = i_blocksize(inode_in) - 1;
141 0 : loff_t new_len = *len;
142 :
143 0 : if ((*len & blkmask) == 0)
144 : return 0;
145 :
146 0 : if (pos_out + *len < i_size_read(inode_out))
147 0 : new_len &= ~blkmask;
148 :
149 0 : if (new_len == *len)
150 : return 0;
151 :
152 0 : if (remap_flags & REMAP_FILE_CAN_SHORTEN) {
153 0 : *len = new_len;
154 0 : return 0;
155 : }
156 :
157 0 : return (remap_flags & REMAP_FILE_DEDUP) ? -EBADE : -EINVAL;
158 : }
159 :
160 : /* Read a page's worth of file data into the page cache. */
161 0 : static struct page *vfs_dedupe_get_page(struct inode *inode, loff_t offset)
162 : {
163 0 : struct page *page;
164 :
165 0 : page = read_mapping_page(inode->i_mapping, offset >> PAGE_SHIFT, NULL);
166 0 : if (IS_ERR(page))
167 : return page;
168 0 : if (!PageUptodate(page)) {
169 0 : put_page(page);
170 0 : return ERR_PTR(-EIO);
171 : }
172 : return page;
173 : }
174 :
175 : /*
176 : * Lock two pages, ensuring that we lock in offset order if the pages are from
177 : * the same file.
178 : */
179 0 : static void vfs_lock_two_pages(struct page *page1, struct page *page2)
180 : {
181 : /* Always lock in order of increasing index. */
182 0 : if (page1->index > page2->index)
183 0 : swap(page1, page2);
184 :
185 0 : lock_page(page1);
186 0 : if (page1 != page2)
187 0 : lock_page(page2);
188 0 : }
189 :
190 : /* Unlock two pages, being careful not to unlock the same page twice. */
191 0 : static void vfs_unlock_two_pages(struct page *page1, struct page *page2)
192 : {
193 0 : unlock_page(page1);
194 0 : if (page1 != page2)
195 0 : unlock_page(page2);
196 0 : }
197 :
198 : /*
199 : * Compare extents of two files to see if they are the same.
200 : * Caller must have locked both inodes to prevent write races.
201 : */
202 0 : static int vfs_dedupe_file_range_compare(struct inode *src, loff_t srcoff,
203 : struct inode *dest, loff_t destoff,
204 : loff_t len, bool *is_same)
205 : {
206 0 : loff_t src_poff;
207 0 : loff_t dest_poff;
208 0 : void *src_addr;
209 0 : void *dest_addr;
210 0 : struct page *src_page;
211 0 : struct page *dest_page;
212 0 : loff_t cmp_len;
213 0 : bool same;
214 0 : int error;
215 :
216 0 : error = -EINVAL;
217 0 : same = true;
218 0 : while (len) {
219 0 : src_poff = srcoff & (PAGE_SIZE - 1);
220 0 : dest_poff = destoff & (PAGE_SIZE - 1);
221 0 : cmp_len = min(PAGE_SIZE - src_poff,
222 : PAGE_SIZE - dest_poff);
223 0 : cmp_len = min(cmp_len, len);
224 0 : if (cmp_len <= 0)
225 0 : goto out_error;
226 :
227 0 : src_page = vfs_dedupe_get_page(src, srcoff);
228 0 : if (IS_ERR(src_page)) {
229 0 : error = PTR_ERR(src_page);
230 0 : goto out_error;
231 : }
232 0 : dest_page = vfs_dedupe_get_page(dest, destoff);
233 0 : if (IS_ERR(dest_page)) {
234 0 : error = PTR_ERR(dest_page);
235 0 : put_page(src_page);
236 0 : goto out_error;
237 : }
238 :
239 0 : vfs_lock_two_pages(src_page, dest_page);
240 :
241 : /*
242 : * Now that we've locked both pages, make sure they're still
243 : * mapped to the file data we're interested in. If not,
244 : * someone is invalidating pages on us and we lose.
245 : */
246 0 : if (!PageUptodate(src_page) || !PageUptodate(dest_page) ||
247 0 : src_page->mapping != src->i_mapping ||
248 0 : dest_page->mapping != dest->i_mapping) {
249 0 : same = false;
250 0 : goto unlock;
251 : }
252 :
253 0 : src_addr = kmap_atomic(src_page);
254 0 : dest_addr = kmap_atomic(dest_page);
255 :
256 0 : flush_dcache_page(src_page);
257 0 : flush_dcache_page(dest_page);
258 :
259 0 : if (memcmp(src_addr + src_poff, dest_addr + dest_poff, cmp_len))
260 0 : same = false;
261 :
262 0 : kunmap_atomic(dest_addr);
263 0 : kunmap_atomic(src_addr);
264 0 : unlock:
265 0 : vfs_unlock_two_pages(src_page, dest_page);
266 0 : put_page(dest_page);
267 0 : put_page(src_page);
268 :
269 0 : if (!same)
270 : break;
271 :
272 0 : srcoff += cmp_len;
273 0 : destoff += cmp_len;
274 0 : len -= cmp_len;
275 : }
276 :
277 0 : *is_same = same;
278 0 : return 0;
279 :
280 : out_error:
281 : return error;
282 : }
283 :
284 : /*
285 : * Check that the two inodes are eligible for cloning, the ranges make
286 : * sense, and then flush all dirty data. Caller must ensure that the
287 : * inodes have been locked against any other modifications.
288 : *
289 : * If there's an error, then the usual negative error code is returned.
290 : * Otherwise returns 0 with *len set to the request length.
291 : */
292 0 : int generic_remap_file_range_prep(struct file *file_in, loff_t pos_in,
293 : struct file *file_out, loff_t pos_out,
294 : loff_t *len, unsigned int remap_flags)
295 : {
296 0 : struct inode *inode_in = file_inode(file_in);
297 0 : struct inode *inode_out = file_inode(file_out);
298 0 : bool same_inode = (inode_in == inode_out);
299 0 : int ret;
300 :
301 : /* Don't touch certain kinds of inodes */
302 0 : if (IS_IMMUTABLE(inode_out))
303 : return -EPERM;
304 :
305 0 : if (IS_SWAPFILE(inode_in) || IS_SWAPFILE(inode_out))
306 : return -ETXTBSY;
307 :
308 : /* Don't reflink dirs, pipes, sockets... */
309 0 : if (S_ISDIR(inode_in->i_mode) || S_ISDIR(inode_out->i_mode))
310 : return -EISDIR;
311 0 : if (!S_ISREG(inode_in->i_mode) || !S_ISREG(inode_out->i_mode))
312 : return -EINVAL;
313 :
314 : /* Zero length dedupe exits immediately; reflink goes to EOF. */
315 0 : if (*len == 0) {
316 0 : loff_t isize = i_size_read(inode_in);
317 :
318 0 : if ((remap_flags & REMAP_FILE_DEDUP) || pos_in == isize)
319 : return 0;
320 0 : if (pos_in > isize)
321 : return -EINVAL;
322 0 : *len = isize - pos_in;
323 0 : if (*len == 0)
324 : return 0;
325 : }
326 :
327 : /* Check that we don't violate system file offset limits. */
328 0 : ret = generic_remap_checks(file_in, pos_in, file_out, pos_out, len,
329 : remap_flags);
330 0 : if (ret)
331 : return ret;
332 :
333 : /* Wait for the completion of any pending IOs on both files */
334 0 : inode_dio_wait(inode_in);
335 0 : if (!same_inode)
336 0 : inode_dio_wait(inode_out);
337 :
338 0 : ret = filemap_write_and_wait_range(inode_in->i_mapping,
339 0 : pos_in, pos_in + *len - 1);
340 0 : if (ret)
341 : return ret;
342 :
343 0 : ret = filemap_write_and_wait_range(inode_out->i_mapping,
344 0 : pos_out, pos_out + *len - 1);
345 0 : if (ret)
346 : return ret;
347 :
348 : /*
349 : * Check that the extents are the same.
350 : */
351 0 : if (remap_flags & REMAP_FILE_DEDUP) {
352 0 : bool is_same = false;
353 :
354 0 : ret = vfs_dedupe_file_range_compare(inode_in, pos_in,
355 : inode_out, pos_out, *len, &is_same);
356 0 : if (ret)
357 0 : return ret;
358 0 : if (!is_same)
359 : return -EBADE;
360 : }
361 :
362 0 : ret = generic_remap_check_len(inode_in, inode_out, pos_out, len,
363 : remap_flags);
364 0 : if (ret)
365 : return ret;
366 :
367 : /* If can't alter the file contents, we're done. */
368 0 : if (!(remap_flags & REMAP_FILE_DEDUP))
369 0 : ret = file_modified(file_out);
370 :
371 : return ret;
372 : }
373 : EXPORT_SYMBOL(generic_remap_file_range_prep);
374 :
375 0 : loff_t do_clone_file_range(struct file *file_in, loff_t pos_in,
376 : struct file *file_out, loff_t pos_out,
377 : loff_t len, unsigned int remap_flags)
378 : {
379 0 : loff_t ret;
380 :
381 0 : WARN_ON_ONCE(remap_flags & REMAP_FILE_DEDUP);
382 :
383 : /*
384 : * FICLONE/FICLONERANGE ioctls enforce that src and dest files are on
385 : * the same mount. Practically, they only need to be on the same file
386 : * system.
387 : */
388 0 : if (file_inode(file_in)->i_sb != file_inode(file_out)->i_sb)
389 : return -EXDEV;
390 :
391 0 : ret = generic_file_rw_checks(file_in, file_out);
392 0 : if (ret < 0)
393 : return ret;
394 :
395 0 : if (!file_in->f_op->remap_file_range)
396 : return -EOPNOTSUPP;
397 :
398 0 : ret = remap_verify_area(file_in, pos_in, len, false);
399 0 : if (ret)
400 : return ret;
401 :
402 0 : ret = remap_verify_area(file_out, pos_out, len, true);
403 0 : if (ret)
404 : return ret;
405 :
406 0 : ret = file_in->f_op->remap_file_range(file_in, pos_in,
407 : file_out, pos_out, len, remap_flags);
408 0 : if (ret < 0)
409 : return ret;
410 :
411 0 : fsnotify_access(file_in);
412 0 : fsnotify_modify(file_out);
413 0 : return ret;
414 : }
415 : EXPORT_SYMBOL(do_clone_file_range);
416 :
417 0 : loff_t vfs_clone_file_range(struct file *file_in, loff_t pos_in,
418 : struct file *file_out, loff_t pos_out,
419 : loff_t len, unsigned int remap_flags)
420 : {
421 0 : loff_t ret;
422 :
423 0 : file_start_write(file_out);
424 0 : ret = do_clone_file_range(file_in, pos_in, file_out, pos_out, len,
425 : remap_flags);
426 0 : file_end_write(file_out);
427 :
428 0 : return ret;
429 : }
430 : EXPORT_SYMBOL(vfs_clone_file_range);
431 :
432 : /* Check whether we are allowed to dedupe the destination file */
433 0 : static bool allow_file_dedupe(struct file *file)
434 : {
435 0 : struct user_namespace *mnt_userns = file_mnt_user_ns(file);
436 0 : struct inode *inode = file_inode(file);
437 :
438 0 : if (capable(CAP_SYS_ADMIN))
439 : return true;
440 0 : if (file->f_mode & FMODE_WRITE)
441 : return true;
442 0 : if (uid_eq(current_fsuid(), i_uid_into_mnt(mnt_userns, inode)))
443 : return true;
444 0 : if (!inode_permission(mnt_userns, inode, MAY_WRITE))
445 0 : return true;
446 : return false;
447 : }
448 :
449 0 : loff_t vfs_dedupe_file_range_one(struct file *src_file, loff_t src_pos,
450 : struct file *dst_file, loff_t dst_pos,
451 : loff_t len, unsigned int remap_flags)
452 : {
453 0 : loff_t ret;
454 :
455 0 : WARN_ON_ONCE(remap_flags & ~(REMAP_FILE_DEDUP |
456 : REMAP_FILE_CAN_SHORTEN));
457 :
458 0 : ret = mnt_want_write_file(dst_file);
459 0 : if (ret)
460 : return ret;
461 :
462 : /*
463 : * This is redundant if called from vfs_dedupe_file_range(), but other
464 : * callers need it and it's not performance sesitive...
465 : */
466 0 : ret = remap_verify_area(src_file, src_pos, len, false);
467 0 : if (ret)
468 0 : goto out_drop_write;
469 :
470 0 : ret = remap_verify_area(dst_file, dst_pos, len, true);
471 0 : if (ret)
472 0 : goto out_drop_write;
473 :
474 0 : ret = -EPERM;
475 0 : if (!allow_file_dedupe(dst_file))
476 0 : goto out_drop_write;
477 :
478 0 : ret = -EXDEV;
479 0 : if (src_file->f_path.mnt != dst_file->f_path.mnt)
480 0 : goto out_drop_write;
481 :
482 0 : ret = -EISDIR;
483 0 : if (S_ISDIR(file_inode(dst_file)->i_mode))
484 0 : goto out_drop_write;
485 :
486 0 : ret = -EINVAL;
487 0 : if (!dst_file->f_op->remap_file_range)
488 0 : goto out_drop_write;
489 :
490 0 : if (len == 0) {
491 0 : ret = 0;
492 0 : goto out_drop_write;
493 : }
494 :
495 0 : ret = dst_file->f_op->remap_file_range(src_file, src_pos, dst_file,
496 : dst_pos, len, remap_flags | REMAP_FILE_DEDUP);
497 0 : out_drop_write:
498 0 : mnt_drop_write_file(dst_file);
499 :
500 0 : return ret;
501 : }
502 : EXPORT_SYMBOL(vfs_dedupe_file_range_one);
503 :
504 0 : int vfs_dedupe_file_range(struct file *file, struct file_dedupe_range *same)
505 : {
506 0 : struct file_dedupe_range_info *info;
507 0 : struct inode *src = file_inode(file);
508 0 : u64 off;
509 0 : u64 len;
510 0 : int i;
511 0 : int ret;
512 0 : u16 count = same->dest_count;
513 0 : loff_t deduped;
514 :
515 0 : if (!(file->f_mode & FMODE_READ))
516 : return -EINVAL;
517 :
518 0 : if (same->reserved1 || same->reserved2)
519 : return -EINVAL;
520 :
521 0 : off = same->src_offset;
522 0 : len = same->src_length;
523 :
524 0 : if (S_ISDIR(src->i_mode))
525 : return -EISDIR;
526 :
527 0 : if (!S_ISREG(src->i_mode))
528 : return -EINVAL;
529 :
530 0 : if (!file->f_op->remap_file_range)
531 : return -EOPNOTSUPP;
532 :
533 0 : ret = remap_verify_area(file, off, len, false);
534 0 : if (ret < 0)
535 : return ret;
536 0 : ret = 0;
537 :
538 0 : if (off + len > i_size_read(src))
539 : return -EINVAL;
540 :
541 : /* Arbitrary 1G limit on a single dedupe request, can be raised. */
542 0 : len = min_t(u64, len, 1 << 30);
543 :
544 : /* pre-format output fields to sane values */
545 0 : for (i = 0; i < count; i++) {
546 0 : same->info[i].bytes_deduped = 0ULL;
547 0 : same->info[i].status = FILE_DEDUPE_RANGE_SAME;
548 : }
549 :
550 0 : for (i = 0, info = same->info; i < count; i++, info++) {
551 0 : struct fd dst_fd = fdget(info->dest_fd);
552 0 : struct file *dst_file = dst_fd.file;
553 :
554 0 : if (!dst_file) {
555 0 : info->status = -EBADF;
556 0 : goto next_loop;
557 : }
558 :
559 0 : if (info->reserved) {
560 0 : info->status = -EINVAL;
561 0 : goto next_fdput;
562 : }
563 :
564 0 : deduped = vfs_dedupe_file_range_one(file, off, dst_file,
565 0 : info->dest_offset, len,
566 : REMAP_FILE_CAN_SHORTEN);
567 0 : if (deduped == -EBADE)
568 0 : info->status = FILE_DEDUPE_RANGE_DIFFERS;
569 0 : else if (deduped < 0)
570 0 : info->status = deduped;
571 : else
572 0 : info->bytes_deduped = len;
573 :
574 0 : next_fdput:
575 0 : fdput(dst_fd);
576 0 : next_loop:
577 0 : if (fatal_signal_pending(current))
578 : break;
579 : }
580 : return ret;
581 : }
582 : EXPORT_SYMBOL(vfs_dedupe_file_range);
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