1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * Copyright (c) 2020-2024 Oracle. All Rights Reserved. 4 * Author: Darrick J. Wong <djwong@kernel.org> 5 */ 6 #include "xfs.h" 7 #include "xfs_shared.h" 8 #include "xfs_format.h" 9 #include "xfs_log_format.h" 10 #include "xfs_trans_resv.h" 11 #include "xfs_mount.h" 12 #include "xfs_defer.h" 13 #include "xfs_inode.h" 14 #include "xfs_trans.h" 15 #include "xfs_quota.h" 16 #include "xfs_bmap_util.h" 17 #include "xfs_reflink.h" 18 #include "xfs_trace.h" 19 #include "xfs_exchrange.h" 20 #include "xfs_exchmaps.h" 21 #include "xfs_sb.h" 22 #include "xfs_icache.h" 23 #include "xfs_log.h" 24 #include "xfs_rtbitmap.h" 25 #include <linux/fsnotify.h> 26 27 /* Lock (and optionally join) two inodes for a file range exchange. */ 28 void 29 xfs_exchrange_ilock( 30 struct xfs_trans *tp, 31 struct xfs_inode *ip1, 32 struct xfs_inode *ip2) 33 { 34 if (ip1 != ip2) 35 xfs_lock_two_inodes(ip1, XFS_ILOCK_EXCL, 36 ip2, XFS_ILOCK_EXCL); 37 else 38 xfs_ilock(ip1, XFS_ILOCK_EXCL); 39 if (tp) { 40 xfs_trans_ijoin(tp, ip1, 0); 41 if (ip2 != ip1) 42 xfs_trans_ijoin(tp, ip2, 0); 43 } 44 45 } 46 47 /* Unlock two inodes after a file range exchange operation. */ 48 void 49 xfs_exchrange_iunlock( 50 struct xfs_inode *ip1, 51 struct xfs_inode *ip2) 52 { 53 if (ip2 != ip1) 54 xfs_iunlock(ip2, XFS_ILOCK_EXCL); 55 xfs_iunlock(ip1, XFS_ILOCK_EXCL); 56 } 57 58 /* 59 * Estimate the resource requirements to exchange file contents between the two 60 * files. The caller is required to hold the IOLOCK and the MMAPLOCK and to 61 * have flushed both inodes' pagecache and active direct-ios. 62 */ 63 int 64 xfs_exchrange_estimate( 65 struct xfs_exchmaps_req *req) 66 { 67 int error; 68 69 xfs_exchrange_ilock(NULL, req->ip1, req->ip2); 70 error = xfs_exchmaps_estimate(req); 71 xfs_exchrange_iunlock(req->ip1, req->ip2); 72 return error; 73 } 74 75 /* 76 * Check that file2's metadata agree with the snapshot that we took for the 77 * range commit request. 78 * 79 * This should be called after the filesystem has locked /all/ inode metadata 80 * against modification. 81 */ 82 STATIC int 83 xfs_exchrange_check_freshness( 84 const struct xfs_exchrange *fxr, 85 struct xfs_inode *ip2) 86 { 87 struct inode *inode2 = VFS_I(ip2); 88 struct timespec64 ctime = inode_get_ctime(inode2); 89 struct timespec64 mtime = inode_get_mtime(inode2); 90 91 trace_xfs_exchrange_freshness(fxr, ip2); 92 93 /* Check that file2 hasn't otherwise been modified. */ 94 if (fxr->file2_ino != ip2->i_ino || 95 fxr->file2_gen != inode2->i_generation || 96 !timespec64_equal(&fxr->file2_ctime, &ctime) || 97 !timespec64_equal(&fxr->file2_mtime, &mtime)) 98 return -EBUSY; 99 100 return 0; 101 } 102 103 #define QRETRY_IP1 (0x1) 104 #define QRETRY_IP2 (0x2) 105 106 /* 107 * Obtain a quota reservation to make sure we don't hit EDQUOT. We can skip 108 * this if quota enforcement is disabled or if both inodes' dquots are the 109 * same. The qretry structure must be initialized to zeroes before the first 110 * call to this function. 111 */ 112 STATIC int 113 xfs_exchrange_reserve_quota( 114 struct xfs_trans *tp, 115 const struct xfs_exchmaps_req *req, 116 unsigned int *qretry) 117 { 118 int64_t ddelta, rdelta; 119 int ip1_error = 0; 120 int error; 121 122 ASSERT(!xfs_is_metadir_inode(req->ip1)); 123 ASSERT(!xfs_is_metadir_inode(req->ip2)); 124 125 /* 126 * Don't bother with a quota reservation if we're not enforcing them 127 * or the two inodes have the same dquots. 128 */ 129 if (!XFS_IS_QUOTA_ON(tp->t_mountp) || req->ip1 == req->ip2 || 130 (req->ip1->i_udquot == req->ip2->i_udquot && 131 req->ip1->i_gdquot == req->ip2->i_gdquot && 132 req->ip1->i_pdquot == req->ip2->i_pdquot)) 133 return 0; 134 135 *qretry = 0; 136 137 /* 138 * For each file, compute the net gain in the number of regular blocks 139 * that will be mapped into that file and reserve that much quota. The 140 * quota counts must be able to absorb at least that much space. 141 */ 142 ddelta = req->ip2_bcount - req->ip1_bcount; 143 rdelta = req->ip2_rtbcount - req->ip1_rtbcount; 144 if (ddelta > 0 || rdelta > 0) { 145 error = xfs_trans_reserve_quota_nblks(tp, req->ip1, 146 ddelta > 0 ? ddelta : 0, 147 rdelta > 0 ? rdelta : 0, 148 false); 149 if (error == -EDQUOT || error == -ENOSPC) { 150 /* 151 * Save this error and see what happens if we try to 152 * reserve quota for ip2. Then report both. 153 */ 154 *qretry |= QRETRY_IP1; 155 ip1_error = error; 156 error = 0; 157 } 158 if (error) 159 return error; 160 } 161 if (ddelta < 0 || rdelta < 0) { 162 error = xfs_trans_reserve_quota_nblks(tp, req->ip2, 163 ddelta < 0 ? -ddelta : 0, 164 rdelta < 0 ? -rdelta : 0, 165 false); 166 if (error == -EDQUOT || error == -ENOSPC) 167 *qretry |= QRETRY_IP2; 168 if (error) 169 return error; 170 } 171 if (ip1_error) 172 return ip1_error; 173 174 /* 175 * For each file, forcibly reserve the gross gain in mapped blocks so 176 * that we don't trip over any quota block reservation assertions. 177 * We must reserve the gross gain because the quota code subtracts from 178 * bcount the number of blocks that we unmap; it does not add that 179 * quantity back to the quota block reservation. 180 */ 181 error = xfs_trans_reserve_quota_nblks(tp, req->ip1, req->ip1_bcount, 182 req->ip1_rtbcount, true); 183 if (error) 184 return error; 185 186 return xfs_trans_reserve_quota_nblks(tp, req->ip2, req->ip2_bcount, 187 req->ip2_rtbcount, true); 188 } 189 190 /* Exchange the mappings (and hence the contents) of two files' forks. */ 191 STATIC int 192 xfs_exchrange_mappings( 193 const struct xfs_exchrange *fxr, 194 struct xfs_inode *ip1, 195 struct xfs_inode *ip2) 196 { 197 struct xfs_mount *mp = ip1->i_mount; 198 struct xfs_exchmaps_req req = { 199 .ip1 = ip1, 200 .ip2 = ip2, 201 .startoff1 = XFS_B_TO_FSBT(mp, fxr->file1_offset), 202 .startoff2 = XFS_B_TO_FSBT(mp, fxr->file2_offset), 203 .blockcount = XFS_B_TO_FSB(mp, fxr->length), 204 }; 205 struct xfs_trans *tp; 206 unsigned int qretry; 207 bool retried = false; 208 int error; 209 210 trace_xfs_exchrange_mappings(fxr, ip1, ip2); 211 212 if (fxr->flags & XFS_EXCHANGE_RANGE_TO_EOF) 213 req.flags |= XFS_EXCHMAPS_SET_SIZES; 214 if (fxr->flags & XFS_EXCHANGE_RANGE_FILE1_WRITTEN) 215 req.flags |= XFS_EXCHMAPS_INO1_WRITTEN; 216 217 /* 218 * Round the request length up to the nearest file allocation unit. 219 * The prep function already checked that the request offsets and 220 * length in @fxr are safe to round up. 221 */ 222 if (xfs_inode_has_bigrtalloc(ip2)) 223 req.blockcount = xfs_blen_roundup_rtx(mp, req.blockcount); 224 225 error = xfs_exchrange_estimate(&req); 226 if (error) 227 return error; 228 229 retry: 230 /* Allocate the transaction, lock the inodes, and join them. */ 231 error = xfs_trans_alloc(mp, &M_RES(mp)->tr_write, req.resblks, 0, 232 XFS_TRANS_RES_FDBLKS, &tp); 233 if (error) 234 return error; 235 236 xfs_exchrange_ilock(tp, ip1, ip2); 237 238 trace_xfs_exchrange_before(ip2, 2); 239 trace_xfs_exchrange_before(ip1, 1); 240 241 error = xfs_exchmaps_check_forks(mp, &req); 242 if (error) 243 goto out_trans_cancel; 244 245 /* 246 * Reserve ourselves some quota if any of them are in enforcing mode. 247 * In theory we only need enough to satisfy the change in the number 248 * of blocks between the two ranges being remapped. 249 */ 250 error = xfs_exchrange_reserve_quota(tp, &req, &qretry); 251 if ((error == -EDQUOT || error == -ENOSPC) && !retried) { 252 xfs_trans_cancel(tp); 253 xfs_exchrange_iunlock(ip1, ip2); 254 if (qretry & QRETRY_IP1) 255 xfs_blockgc_free_quota(ip1, 0); 256 if (qretry & QRETRY_IP2) 257 xfs_blockgc_free_quota(ip2, 0); 258 retried = true; 259 goto retry; 260 } 261 if (error) 262 goto out_trans_cancel; 263 264 /* If we got this far on a dry run, all parameters are ok. */ 265 if (fxr->flags & XFS_EXCHANGE_RANGE_DRY_RUN) 266 goto out_trans_cancel; 267 268 /* Update the mtime and ctime of both files. */ 269 if (fxr->flags & __XFS_EXCHANGE_RANGE_UPD_CMTIME1) 270 xfs_trans_ichgtime(tp, ip1, XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG); 271 if (fxr->flags & __XFS_EXCHANGE_RANGE_UPD_CMTIME2) 272 xfs_trans_ichgtime(tp, ip2, XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG); 273 274 xfs_exchange_mappings(tp, &req); 275 276 /* 277 * Force the log to persist metadata updates if the caller or the 278 * administrator requires this. The generic prep function already 279 * flushed the relevant parts of the page cache. 280 */ 281 if (xfs_has_wsync(mp) || (fxr->flags & XFS_EXCHANGE_RANGE_DSYNC)) 282 xfs_trans_set_sync(tp); 283 284 error = xfs_trans_commit(tp); 285 286 trace_xfs_exchrange_after(ip2, 2); 287 trace_xfs_exchrange_after(ip1, 1); 288 289 if (error) 290 goto out_unlock; 291 292 /* 293 * If the caller wanted us to exchange the contents of two complete 294 * files of unequal length, exchange the incore sizes now. This should 295 * be safe because we flushed both files' page caches, exchanged all 296 * the mappings, and updated the ondisk sizes. 297 */ 298 if (fxr->flags & XFS_EXCHANGE_RANGE_TO_EOF) { 299 loff_t temp; 300 301 temp = i_size_read(VFS_I(ip2)); 302 i_size_write(VFS_I(ip2), i_size_read(VFS_I(ip1))); 303 i_size_write(VFS_I(ip1), temp); 304 } 305 306 out_unlock: 307 xfs_exchrange_iunlock(ip1, ip2); 308 return error; 309 310 out_trans_cancel: 311 xfs_trans_cancel(tp); 312 goto out_unlock; 313 } 314 315 /* 316 * Generic code for exchanging ranges of two files via XFS_IOC_EXCHANGE_RANGE. 317 * This part deals with struct file objects and byte ranges and does not deal 318 * with XFS-specific data structures such as xfs_inodes and block ranges. This 319 * separation may some day facilitate porting to another filesystem. 320 * 321 * The goal is to exchange fxr.length bytes starting at fxr.file1_offset in 322 * file1 with the same number of bytes starting at fxr.file2_offset in file2. 323 * Implementations must call xfs_exchange_range_prep to prepare the two 324 * files prior to taking locks; and they must update the inode change and mod 325 * times of both files as part of the metadata update. The timestamp update 326 * and freshness checks must be done atomically as part of the data exchange 327 * operation to ensure correctness of the freshness check. 328 * xfs_exchange_range_finish must be called after the operation completes 329 * successfully but before locks are dropped. 330 */ 331 332 /* 333 * Performs necessary checks before doing a range exchange, having stabilized 334 * mutable inode attributes via i_rwsem. 335 */ 336 static inline int 337 xfs_exchange_range_checks( 338 struct xfs_exchrange *fxr, 339 unsigned int alloc_unit) 340 { 341 struct inode *inode1 = file_inode(fxr->file1); 342 loff_t size1 = i_size_read(inode1); 343 struct inode *inode2 = file_inode(fxr->file2); 344 loff_t size2 = i_size_read(inode2); 345 uint64_t allocmask = alloc_unit - 1; 346 int64_t test_len; 347 uint64_t blen; 348 loff_t tmp; 349 int error; 350 351 /* Don't touch certain kinds of inodes */ 352 if (IS_IMMUTABLE(inode1) || IS_IMMUTABLE(inode2)) 353 return -EPERM; 354 if (IS_SWAPFILE(inode1) || IS_SWAPFILE(inode2)) 355 return -ETXTBSY; 356 357 /* Ranges cannot start after EOF. */ 358 if (fxr->file1_offset > size1 || fxr->file2_offset > size2) 359 return -EINVAL; 360 361 if (fxr->flags & XFS_EXCHANGE_RANGE_TO_EOF) { 362 /* 363 * If the caller said to exchange to EOF, we set the length of 364 * the request large enough to cover everything to the end of 365 * both files. 366 */ 367 fxr->length = max_t(int64_t, size1 - fxr->file1_offset, 368 size2 - fxr->file2_offset); 369 } else { 370 /* 371 * Otherwise we require both ranges to end within EOF. 372 */ 373 if (fxr->file1_offset + fxr->length > size1 || 374 fxr->file2_offset + fxr->length > size2) 375 return -EINVAL; 376 } 377 378 /* 379 * The start of both ranges must be aligned to the file allocation 380 * unit. 381 */ 382 if (!IS_ALIGNED(fxr->file1_offset, alloc_unit) || 383 !IS_ALIGNED(fxr->file2_offset, alloc_unit)) 384 return -EINVAL; 385 386 /* Ensure offsets don't wrap. */ 387 if (check_add_overflow(fxr->file1_offset, fxr->length, &tmp) || 388 check_add_overflow(fxr->file2_offset, fxr->length, &tmp)) 389 return -EINVAL; 390 391 /* 392 * Make sure we don't hit any file size limits. If we hit any size 393 * limits such that test_length was adjusted, we abort the whole 394 * operation. 395 */ 396 test_len = fxr->length; 397 error = generic_write_check_limits(fxr->file2, fxr->file2_offset, 398 &test_len); 399 if (error) 400 return error; 401 error = generic_write_check_limits(fxr->file1, fxr->file1_offset, 402 &test_len); 403 if (error) 404 return error; 405 if (test_len != fxr->length) 406 return -EINVAL; 407 408 /* 409 * If the user wanted us to exchange up to the infile's EOF, round up 410 * to the next allocation unit boundary for this check. Do the same 411 * for the outfile. 412 * 413 * Otherwise, reject the range length if it's not aligned to an 414 * allocation unit. 415 */ 416 if (fxr->file1_offset + fxr->length == size1) 417 blen = ALIGN(size1, alloc_unit) - fxr->file1_offset; 418 else if (fxr->file2_offset + fxr->length == size2) 419 blen = ALIGN(size2, alloc_unit) - fxr->file2_offset; 420 else if (!IS_ALIGNED(fxr->length, alloc_unit)) 421 return -EINVAL; 422 else 423 blen = fxr->length; 424 425 /* Don't allow overlapped exchanges within the same file. */ 426 if (inode1 == inode2 && 427 fxr->file2_offset + blen > fxr->file1_offset && 428 fxr->file1_offset + blen > fxr->file2_offset) 429 return -EINVAL; 430 431 /* 432 * Ensure that we don't exchange a partial EOF block into the middle of 433 * another file. 434 */ 435 if ((fxr->length & allocmask) == 0) 436 return 0; 437 438 blen = fxr->length; 439 if (fxr->file2_offset + blen < size2) 440 blen &= ~allocmask; 441 442 if (fxr->file1_offset + blen < size1) 443 blen &= ~allocmask; 444 445 return blen == fxr->length ? 0 : -EINVAL; 446 } 447 448 /* 449 * Check that the two inodes are eligible for range exchanges, the ranges make 450 * sense, and then flush all dirty data. Caller must ensure that the inodes 451 * have been locked against any other modifications. 452 */ 453 static inline int 454 xfs_exchange_range_prep( 455 struct xfs_exchrange *fxr, 456 unsigned int alloc_unit) 457 { 458 struct inode *inode1 = file_inode(fxr->file1); 459 struct inode *inode2 = file_inode(fxr->file2); 460 bool same_inode = (inode1 == inode2); 461 int error; 462 463 /* Check that we don't violate system file offset limits. */ 464 error = xfs_exchange_range_checks(fxr, alloc_unit); 465 if (error || fxr->length == 0) 466 return error; 467 468 /* Wait for the completion of any pending IOs on both files */ 469 inode_dio_wait(inode1); 470 if (!same_inode) 471 inode_dio_wait(inode2); 472 473 error = filemap_write_and_wait_range(inode1->i_mapping, 474 fxr->file1_offset, 475 fxr->file1_offset + fxr->length - 1); 476 if (error) 477 return error; 478 479 error = filemap_write_and_wait_range(inode2->i_mapping, 480 fxr->file2_offset, 481 fxr->file2_offset + fxr->length - 1); 482 if (error) 483 return error; 484 485 /* 486 * If the files or inodes involved require synchronous writes, amend 487 * the request to force the filesystem to flush all data and metadata 488 * to disk after the operation completes. 489 */ 490 if (((fxr->file1->f_flags | fxr->file2->f_flags) & O_SYNC) || 491 IS_SYNC(inode1) || IS_SYNC(inode2)) 492 fxr->flags |= XFS_EXCHANGE_RANGE_DSYNC; 493 494 return 0; 495 } 496 497 /* 498 * Finish a range exchange operation, if it was successful. Caller must ensure 499 * that the inodes are still locked against any other modifications. 500 */ 501 static inline int 502 xfs_exchange_range_finish( 503 struct xfs_exchrange *fxr) 504 { 505 int error; 506 507 error = file_remove_privs(fxr->file1); 508 if (error) 509 return error; 510 if (file_inode(fxr->file1) == file_inode(fxr->file2)) 511 return 0; 512 513 return file_remove_privs(fxr->file2); 514 } 515 516 /* 517 * Check the alignment of an exchange request when the allocation unit size 518 * isn't a power of two. The generic file-level helpers use (fast) 519 * bitmask-based alignment checks, but here we have to use slow long division. 520 */ 521 static int 522 xfs_exchrange_check_rtalign( 523 const struct xfs_exchrange *fxr, 524 struct xfs_inode *ip1, 525 struct xfs_inode *ip2, 526 unsigned int alloc_unit) 527 { 528 uint64_t length = fxr->length; 529 uint64_t blen; 530 loff_t size1, size2; 531 532 size1 = i_size_read(VFS_I(ip1)); 533 size2 = i_size_read(VFS_I(ip2)); 534 535 /* The start of both ranges must be aligned to a rt extent. */ 536 if (!isaligned_64(fxr->file1_offset, alloc_unit) || 537 !isaligned_64(fxr->file2_offset, alloc_unit)) 538 return -EINVAL; 539 540 if (fxr->flags & XFS_EXCHANGE_RANGE_TO_EOF) 541 length = max_t(int64_t, size1 - fxr->file1_offset, 542 size2 - fxr->file2_offset); 543 544 /* 545 * If the user wanted us to exchange up to the infile's EOF, round up 546 * to the next rt extent boundary for this check. Do the same for the 547 * outfile. 548 * 549 * Otherwise, reject the range length if it's not rt extent aligned. 550 * We already confirmed the starting offsets' rt extent block 551 * alignment. 552 */ 553 if (fxr->file1_offset + length == size1) 554 blen = roundup_64(size1, alloc_unit) - fxr->file1_offset; 555 else if (fxr->file2_offset + length == size2) 556 blen = roundup_64(size2, alloc_unit) - fxr->file2_offset; 557 else if (!isaligned_64(length, alloc_unit)) 558 return -EINVAL; 559 else 560 blen = length; 561 562 /* Don't allow overlapped exchanges within the same file. */ 563 if (ip1 == ip2 && 564 fxr->file2_offset + blen > fxr->file1_offset && 565 fxr->file1_offset + blen > fxr->file2_offset) 566 return -EINVAL; 567 568 /* 569 * Ensure that we don't exchange a partial EOF rt extent into the 570 * middle of another file. 571 */ 572 if (isaligned_64(length, alloc_unit)) 573 return 0; 574 575 blen = length; 576 if (fxr->file2_offset + length < size2) 577 blen = rounddown_64(blen, alloc_unit); 578 579 if (fxr->file1_offset + blen < size1) 580 blen = rounddown_64(blen, alloc_unit); 581 582 return blen == length ? 0 : -EINVAL; 583 } 584 585 /* Prepare two files to have their data exchanged. */ 586 STATIC int 587 xfs_exchrange_prep( 588 struct xfs_exchrange *fxr, 589 struct xfs_inode *ip1, 590 struct xfs_inode *ip2) 591 { 592 struct xfs_mount *mp = ip2->i_mount; 593 unsigned int alloc_unit = xfs_inode_alloc_unitsize(ip2); 594 int error; 595 596 trace_xfs_exchrange_prep(fxr, ip1, ip2); 597 598 /* Verify both files are either real-time or non-realtime */ 599 if (XFS_IS_REALTIME_INODE(ip1) != XFS_IS_REALTIME_INODE(ip2)) 600 return -EINVAL; 601 602 /* Check non-power of two alignment issues, if necessary. */ 603 if (!is_power_of_2(alloc_unit)) { 604 error = xfs_exchrange_check_rtalign(fxr, ip1, ip2, alloc_unit); 605 if (error) 606 return error; 607 608 /* 609 * Do the generic file-level checks with the regular block 610 * alignment. 611 */ 612 alloc_unit = mp->m_sb.sb_blocksize; 613 } 614 615 error = xfs_exchange_range_prep(fxr, alloc_unit); 616 if (error || fxr->length == 0) 617 return error; 618 619 if (fxr->flags & __XFS_EXCHANGE_RANGE_CHECK_FRESH2) { 620 error = xfs_exchrange_check_freshness(fxr, ip2); 621 if (error) 622 return error; 623 } 624 625 /* Attach dquots to both inodes before changing block maps. */ 626 error = xfs_qm_dqattach(ip2); 627 if (error) 628 return error; 629 error = xfs_qm_dqattach(ip1); 630 if (error) 631 return error; 632 633 trace_xfs_exchrange_flush(fxr, ip1, ip2); 634 635 /* Flush the relevant ranges of both files. */ 636 error = xfs_flush_unmap_range(ip2, fxr->file2_offset, fxr->length); 637 if (error) 638 return error; 639 error = xfs_flush_unmap_range(ip1, fxr->file1_offset, fxr->length); 640 if (error) 641 return error; 642 643 /* 644 * Cancel CoW fork preallocations for the ranges of both files. The 645 * prep function should have flushed all the dirty data, so the only 646 * CoW mappings remaining should be speculative. 647 */ 648 if (xfs_inode_has_cow_data(ip1)) { 649 error = xfs_reflink_cancel_cow_range(ip1, fxr->file1_offset, 650 fxr->length, true); 651 if (error) 652 return error; 653 } 654 655 if (xfs_inode_has_cow_data(ip2)) { 656 error = xfs_reflink_cancel_cow_range(ip2, fxr->file2_offset, 657 fxr->length, true); 658 if (error) 659 return error; 660 } 661 662 return 0; 663 } 664 665 /* 666 * Exchange contents of files. This is the binding between the generic 667 * file-level concepts and the XFS inode-specific implementation. 668 */ 669 STATIC int 670 xfs_exchrange_contents( 671 struct xfs_exchrange *fxr) 672 { 673 struct inode *inode1 = file_inode(fxr->file1); 674 struct inode *inode2 = file_inode(fxr->file2); 675 struct xfs_inode *ip1 = XFS_I(inode1); 676 struct xfs_inode *ip2 = XFS_I(inode2); 677 struct xfs_mount *mp = ip1->i_mount; 678 int error; 679 680 if (!xfs_has_exchange_range(mp)) 681 return -EOPNOTSUPP; 682 683 if (fxr->flags & ~(XFS_EXCHANGE_RANGE_ALL_FLAGS | 684 XFS_EXCHANGE_RANGE_PRIV_FLAGS)) 685 return -EINVAL; 686 687 if (xfs_is_shutdown(mp)) 688 return -EIO; 689 690 /* Lock both files against IO */ 691 error = xfs_ilock2_io_mmap(ip1, ip2); 692 if (error) 693 goto out_err; 694 695 /* Prepare and then exchange file contents. */ 696 error = xfs_exchrange_prep(fxr, ip1, ip2); 697 if (error) 698 goto out_unlock; 699 700 error = xfs_exchrange_mappings(fxr, ip1, ip2); 701 if (error) 702 goto out_unlock; 703 704 /* 705 * Finish the exchange by removing special file privileges like any 706 * other file write would do. This may involve turning on support for 707 * logged xattrs if either file has security capabilities. 708 */ 709 error = xfs_exchange_range_finish(fxr); 710 if (error) 711 goto out_unlock; 712 713 out_unlock: 714 xfs_iunlock2_io_mmap(ip1, ip2); 715 out_err: 716 if (error) 717 trace_xfs_exchrange_error(ip2, error, _RET_IP_); 718 return error; 719 } 720 721 /* Exchange parts of two files. */ 722 static int 723 xfs_exchange_range( 724 struct xfs_exchrange *fxr) 725 { 726 struct inode *inode1 = file_inode(fxr->file1); 727 struct inode *inode2 = file_inode(fxr->file2); 728 loff_t check_len = fxr->length; 729 int ret; 730 731 BUILD_BUG_ON(XFS_EXCHANGE_RANGE_ALL_FLAGS & 732 XFS_EXCHANGE_RANGE_PRIV_FLAGS); 733 734 /* Both files must be on the same mount/filesystem. */ 735 if (fxr->file1->f_path.mnt != fxr->file2->f_path.mnt) 736 return -EXDEV; 737 738 if (fxr->flags & ~(XFS_EXCHANGE_RANGE_ALL_FLAGS | 739 __XFS_EXCHANGE_RANGE_CHECK_FRESH2)) 740 return -EINVAL; 741 742 /* Userspace requests only honored for regular files. */ 743 if (S_ISDIR(inode1->i_mode) || S_ISDIR(inode2->i_mode)) 744 return -EISDIR; 745 if (!S_ISREG(inode1->i_mode) || !S_ISREG(inode2->i_mode)) 746 return -EINVAL; 747 748 /* Both files must be opened for read and write. */ 749 if (!(fxr->file1->f_mode & FMODE_READ) || 750 !(fxr->file1->f_mode & FMODE_WRITE) || 751 !(fxr->file2->f_mode & FMODE_READ) || 752 !(fxr->file2->f_mode & FMODE_WRITE)) 753 return -EBADF; 754 755 /* Neither file can be opened append-only. */ 756 if ((fxr->file1->f_flags & O_APPEND) || 757 (fxr->file2->f_flags & O_APPEND)) 758 return -EBADF; 759 760 /* 761 * If we're exchanging to EOF we can't calculate the length until taking 762 * the iolock. Pass a 0 length to remap_verify_area similar to the 763 * FICLONE and FICLONERANGE ioctls that support cloning to EOF as well. 764 */ 765 if (fxr->flags & XFS_EXCHANGE_RANGE_TO_EOF) 766 check_len = 0; 767 ret = remap_verify_area(fxr->file1, fxr->file1_offset, check_len, true); 768 if (ret) 769 return ret; 770 ret = remap_verify_area(fxr->file2, fxr->file2_offset, check_len, true); 771 if (ret) 772 return ret; 773 774 /* Update cmtime if the fd/inode don't forbid it. */ 775 if (!(fxr->file1->f_mode & FMODE_NOCMTIME) && !IS_NOCMTIME(inode1)) 776 fxr->flags |= __XFS_EXCHANGE_RANGE_UPD_CMTIME1; 777 if (!(fxr->file2->f_mode & FMODE_NOCMTIME) && !IS_NOCMTIME(inode2)) 778 fxr->flags |= __XFS_EXCHANGE_RANGE_UPD_CMTIME2; 779 780 file_start_write(fxr->file2); 781 ret = xfs_exchrange_contents(fxr); 782 file_end_write(fxr->file2); 783 if (ret) 784 return ret; 785 786 fsnotify_modify(fxr->file1); 787 if (fxr->file2 != fxr->file1) 788 fsnotify_modify(fxr->file2); 789 return 0; 790 } 791 792 /* Collect exchange-range arguments from userspace. */ 793 long 794 xfs_ioc_exchange_range( 795 struct file *file, 796 struct xfs_exchange_range __user *argp) 797 { 798 struct xfs_exchrange fxr = { 799 .file2 = file, 800 }; 801 struct xfs_exchange_range args; 802 803 if (copy_from_user(&args, argp, sizeof(args))) 804 return -EFAULT; 805 if (memchr_inv(&args.pad, 0, sizeof(args.pad))) 806 return -EINVAL; 807 if (args.flags & ~XFS_EXCHANGE_RANGE_ALL_FLAGS) 808 return -EINVAL; 809 810 fxr.file1_offset = args.file1_offset; 811 fxr.file2_offset = args.file2_offset; 812 fxr.length = args.length; 813 fxr.flags = args.flags; 814 815 CLASS(fd, file1)(args.file1_fd); 816 if (fd_empty(file1)) 817 return -EBADF; 818 fxr.file1 = fd_file(file1); 819 820 return xfs_exchange_range(&fxr); 821 } 822 823 /* Opaque freshness blob for XFS_IOC_COMMIT_RANGE */ 824 struct xfs_commit_range_fresh { 825 xfs_fsid_t fsid; /* m_fixedfsid */ 826 __u64 file2_ino; /* inode number */ 827 __s64 file2_mtime; /* modification time */ 828 __s64 file2_ctime; /* change time */ 829 __s32 file2_mtime_nsec; /* mod time, nsec */ 830 __s32 file2_ctime_nsec; /* change time, nsec */ 831 __u32 file2_gen; /* inode generation */ 832 __u32 magic; /* zero */ 833 }; 834 #define XCR_FRESH_MAGIC 0x444F524B /* DORK */ 835 836 /* Set up a commitrange operation by sampling file2's write-related attrs */ 837 long 838 xfs_ioc_start_commit( 839 struct file *file, 840 struct xfs_commit_range __user *argp) 841 { 842 struct xfs_commit_range args = { }; 843 struct kstat kstat = { }; 844 struct xfs_commit_range_fresh *kern_f; 845 struct xfs_commit_range_fresh __user *user_f; 846 struct inode *inode2 = file_inode(file); 847 struct xfs_inode *ip2 = XFS_I(inode2); 848 const unsigned int lockflags = XFS_IOLOCK_SHARED | 849 XFS_MMAPLOCK_SHARED | 850 XFS_ILOCK_SHARED; 851 852 BUILD_BUG_ON(sizeof(struct xfs_commit_range_fresh) != 853 sizeof(args.file2_freshness)); 854 855 kern_f = (struct xfs_commit_range_fresh *)&args.file2_freshness; 856 857 memcpy(&kern_f->fsid, ip2->i_mount->m_fixedfsid, sizeof(xfs_fsid_t)); 858 859 xfs_ilock(ip2, lockflags); 860 /* Force writing of a distinct ctime if any writes happen. */ 861 fill_mg_cmtime(&kstat, STATX_CTIME | STATX_MTIME, inode2); 862 kern_f->file2_ctime = kstat.ctime.tv_sec; 863 kern_f->file2_ctime_nsec = kstat.ctime.tv_nsec; 864 kern_f->file2_mtime = kstat.mtime.tv_sec; 865 kern_f->file2_mtime_nsec = kstat.mtime.tv_nsec; 866 kern_f->file2_ino = ip2->i_ino; 867 kern_f->file2_gen = inode2->i_generation; 868 kern_f->magic = XCR_FRESH_MAGIC; 869 xfs_iunlock(ip2, lockflags); 870 871 user_f = (struct xfs_commit_range_fresh __user *)&argp->file2_freshness; 872 if (copy_to_user(user_f, kern_f, sizeof(*kern_f))) 873 return -EFAULT; 874 875 return 0; 876 } 877 878 /* 879 * Exchange file1 and file2 contents if file2 has not been written since the 880 * start commit operation. 881 */ 882 long 883 xfs_ioc_commit_range( 884 struct file *file, 885 struct xfs_commit_range __user *argp) 886 { 887 struct xfs_exchrange fxr = { 888 .file2 = file, 889 }; 890 struct xfs_commit_range args; 891 struct xfs_commit_range_fresh *kern_f; 892 struct xfs_inode *ip2 = XFS_I(file_inode(file)); 893 struct xfs_mount *mp = ip2->i_mount; 894 895 kern_f = (struct xfs_commit_range_fresh *)&args.file2_freshness; 896 897 if (copy_from_user(&args, argp, sizeof(args))) 898 return -EFAULT; 899 if (args.flags & ~XFS_EXCHANGE_RANGE_ALL_FLAGS) 900 return -EINVAL; 901 if (kern_f->magic != XCR_FRESH_MAGIC) 902 return -EBUSY; 903 if (memcmp(&kern_f->fsid, mp->m_fixedfsid, sizeof(xfs_fsid_t))) 904 return -EBUSY; 905 906 fxr.file1_offset = args.file1_offset; 907 fxr.file2_offset = args.file2_offset; 908 fxr.length = args.length; 909 fxr.flags = args.flags | __XFS_EXCHANGE_RANGE_CHECK_FRESH2; 910 fxr.file2_ino = kern_f->file2_ino; 911 fxr.file2_gen = kern_f->file2_gen; 912 fxr.file2_mtime.tv_sec = kern_f->file2_mtime; 913 fxr.file2_mtime.tv_nsec = kern_f->file2_mtime_nsec; 914 fxr.file2_ctime.tv_sec = kern_f->file2_ctime; 915 fxr.file2_ctime.tv_nsec = kern_f->file2_ctime_nsec; 916 917 CLASS(fd, file1)(args.file1_fd); 918 if (fd_empty(file1)) 919 return -EBADF; 920 fxr.file1 = fd_file(file1); 921 922 return xfs_exchange_range(&fxr); 923 } 924