1 /* 2 * Copyright (c) 2000-2006 Silicon Graphics, Inc. 3 * All Rights Reserved. 4 * 5 * This program is free software; you can redistribute it and/or 6 * modify it under the terms of the GNU General Public License as 7 * published by the Free Software Foundation. 8 * 9 * This program is distributed in the hope that it would be useful, 10 * but WITHOUT ANY WARRANTY; without even the implied warranty of 11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 12 * GNU General Public License for more details. 13 * 14 * You should have received a copy of the GNU General Public License 15 * along with this program; if not, write the Free Software Foundation, 16 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA 17 */ 18 #include "xfs.h" 19 #include "xfs_fs.h" 20 #include "xfs_format.h" 21 #include "xfs_log.h" 22 #include "xfs_trans.h" 23 #include "xfs_sb.h" 24 #include "xfs_ag.h" 25 #include "xfs_alloc.h" 26 #include "xfs_quota.h" 27 #include "xfs_mount.h" 28 #include "xfs_bmap_btree.h" 29 #include "xfs_alloc_btree.h" 30 #include "xfs_ialloc_btree.h" 31 #include "xfs_dinode.h" 32 #include "xfs_inode.h" 33 #include "xfs_inode_item.h" 34 #include "xfs_btree.h" 35 #include "xfs_bmap.h" 36 #include "xfs_bmap_util.h" 37 #include "xfs_rtalloc.h" 38 #include "xfs_error.h" 39 #include "xfs_itable.h" 40 #include "xfs_attr.h" 41 #include "xfs_buf_item.h" 42 #include "xfs_trans_space.h" 43 #include "xfs_iomap.h" 44 #include "xfs_trace.h" 45 #include "xfs_icache.h" 46 #include "xfs_dquot_item.h" 47 #include "xfs_dquot.h" 48 49 50 #define XFS_WRITEIO_ALIGN(mp,off) (((off) >> mp->m_writeio_log) \ 51 << mp->m_writeio_log) 52 #define XFS_WRITE_IMAPS XFS_BMAP_MAX_NMAP 53 54 STATIC int 55 xfs_iomap_eof_align_last_fsb( 56 xfs_mount_t *mp, 57 xfs_inode_t *ip, 58 xfs_extlen_t extsize, 59 xfs_fileoff_t *last_fsb) 60 { 61 xfs_fileoff_t new_last_fsb = 0; 62 xfs_extlen_t align = 0; 63 int eof, error; 64 65 if (!XFS_IS_REALTIME_INODE(ip)) { 66 /* 67 * Round up the allocation request to a stripe unit 68 * (m_dalign) boundary if the file size is >= stripe unit 69 * size, and we are allocating past the allocation eof. 70 * 71 * If mounted with the "-o swalloc" option the alignment is 72 * increased from the strip unit size to the stripe width. 73 */ 74 if (mp->m_swidth && (mp->m_flags & XFS_MOUNT_SWALLOC)) 75 align = mp->m_swidth; 76 else if (mp->m_dalign) 77 align = mp->m_dalign; 78 79 if (align && XFS_ISIZE(ip) >= XFS_FSB_TO_B(mp, align)) 80 new_last_fsb = roundup_64(*last_fsb, align); 81 } 82 83 /* 84 * Always round up the allocation request to an extent boundary 85 * (when file on a real-time subvolume or has di_extsize hint). 86 */ 87 if (extsize) { 88 if (new_last_fsb) 89 align = roundup_64(new_last_fsb, extsize); 90 else 91 align = extsize; 92 new_last_fsb = roundup_64(*last_fsb, align); 93 } 94 95 if (new_last_fsb) { 96 error = xfs_bmap_eof(ip, new_last_fsb, XFS_DATA_FORK, &eof); 97 if (error) 98 return error; 99 if (eof) 100 *last_fsb = new_last_fsb; 101 } 102 return 0; 103 } 104 105 STATIC int 106 xfs_alert_fsblock_zero( 107 xfs_inode_t *ip, 108 xfs_bmbt_irec_t *imap) 109 { 110 xfs_alert_tag(ip->i_mount, XFS_PTAG_FSBLOCK_ZERO, 111 "Access to block zero in inode %llu " 112 "start_block: %llx start_off: %llx " 113 "blkcnt: %llx extent-state: %x\n", 114 (unsigned long long)ip->i_ino, 115 (unsigned long long)imap->br_startblock, 116 (unsigned long long)imap->br_startoff, 117 (unsigned long long)imap->br_blockcount, 118 imap->br_state); 119 return EFSCORRUPTED; 120 } 121 122 int 123 xfs_iomap_write_direct( 124 xfs_inode_t *ip, 125 xfs_off_t offset, 126 size_t count, 127 xfs_bmbt_irec_t *imap, 128 int nmaps) 129 { 130 xfs_mount_t *mp = ip->i_mount; 131 xfs_fileoff_t offset_fsb; 132 xfs_fileoff_t last_fsb; 133 xfs_filblks_t count_fsb, resaligned; 134 xfs_fsblock_t firstfsb; 135 xfs_extlen_t extsz, temp; 136 int nimaps; 137 int bmapi_flag; 138 int quota_flag; 139 int rt; 140 xfs_trans_t *tp; 141 xfs_bmap_free_t free_list; 142 uint qblocks, resblks, resrtextents; 143 int committed; 144 int error; 145 146 error = xfs_qm_dqattach(ip, 0); 147 if (error) 148 return XFS_ERROR(error); 149 150 rt = XFS_IS_REALTIME_INODE(ip); 151 extsz = xfs_get_extsz_hint(ip); 152 153 offset_fsb = XFS_B_TO_FSBT(mp, offset); 154 last_fsb = XFS_B_TO_FSB(mp, ((xfs_ufsize_t)(offset + count))); 155 if ((offset + count) > XFS_ISIZE(ip)) { 156 error = xfs_iomap_eof_align_last_fsb(mp, ip, extsz, &last_fsb); 157 if (error) 158 return XFS_ERROR(error); 159 } else { 160 if (nmaps && (imap->br_startblock == HOLESTARTBLOCK)) 161 last_fsb = MIN(last_fsb, (xfs_fileoff_t) 162 imap->br_blockcount + 163 imap->br_startoff); 164 } 165 count_fsb = last_fsb - offset_fsb; 166 ASSERT(count_fsb > 0); 167 168 resaligned = count_fsb; 169 if (unlikely(extsz)) { 170 if ((temp = do_mod(offset_fsb, extsz))) 171 resaligned += temp; 172 if ((temp = do_mod(resaligned, extsz))) 173 resaligned += extsz - temp; 174 } 175 176 if (unlikely(rt)) { 177 resrtextents = qblocks = resaligned; 178 resrtextents /= mp->m_sb.sb_rextsize; 179 resblks = XFS_DIOSTRAT_SPACE_RES(mp, 0); 180 quota_flag = XFS_QMOPT_RES_RTBLKS; 181 } else { 182 resrtextents = 0; 183 resblks = qblocks = XFS_DIOSTRAT_SPACE_RES(mp, resaligned); 184 quota_flag = XFS_QMOPT_RES_REGBLKS; 185 } 186 187 /* 188 * Allocate and setup the transaction 189 */ 190 tp = xfs_trans_alloc(mp, XFS_TRANS_DIOSTRAT); 191 error = xfs_trans_reserve(tp, &M_RES(mp)->tr_write, 192 resblks, resrtextents); 193 /* 194 * Check for running out of space, note: need lock to return 195 */ 196 if (error) { 197 xfs_trans_cancel(tp, 0); 198 return XFS_ERROR(error); 199 } 200 201 xfs_ilock(ip, XFS_ILOCK_EXCL); 202 203 error = xfs_trans_reserve_quota_nblks(tp, ip, qblocks, 0, quota_flag); 204 if (error) 205 goto out_trans_cancel; 206 207 xfs_trans_ijoin(tp, ip, 0); 208 209 bmapi_flag = 0; 210 if (offset < XFS_ISIZE(ip) || extsz) 211 bmapi_flag |= XFS_BMAPI_PREALLOC; 212 213 /* 214 * From this point onwards we overwrite the imap pointer that the 215 * caller gave to us. 216 */ 217 xfs_bmap_init(&free_list, &firstfsb); 218 nimaps = 1; 219 error = xfs_bmapi_write(tp, ip, offset_fsb, count_fsb, bmapi_flag, 220 &firstfsb, 0, imap, &nimaps, &free_list); 221 if (error) 222 goto out_bmap_cancel; 223 224 /* 225 * Complete the transaction 226 */ 227 error = xfs_bmap_finish(&tp, &free_list, &committed); 228 if (error) 229 goto out_bmap_cancel; 230 error = xfs_trans_commit(tp, XFS_TRANS_RELEASE_LOG_RES); 231 if (error) 232 goto out_unlock; 233 234 /* 235 * Copy any maps to caller's array and return any error. 236 */ 237 if (nimaps == 0) { 238 error = XFS_ERROR(ENOSPC); 239 goto out_unlock; 240 } 241 242 if (!(imap->br_startblock || XFS_IS_REALTIME_INODE(ip))) 243 error = xfs_alert_fsblock_zero(ip, imap); 244 245 out_unlock: 246 xfs_iunlock(ip, XFS_ILOCK_EXCL); 247 return error; 248 249 out_bmap_cancel: 250 xfs_bmap_cancel(&free_list); 251 xfs_trans_unreserve_quota_nblks(tp, ip, (long)qblocks, 0, quota_flag); 252 out_trans_cancel: 253 xfs_trans_cancel(tp, XFS_TRANS_RELEASE_LOG_RES | XFS_TRANS_ABORT); 254 goto out_unlock; 255 } 256 257 /* 258 * If the caller is doing a write at the end of the file, then extend the 259 * allocation out to the file system's write iosize. We clean up any extra 260 * space left over when the file is closed in xfs_inactive(). 261 * 262 * If we find we already have delalloc preallocation beyond EOF, don't do more 263 * preallocation as it it not needed. 264 */ 265 STATIC int 266 xfs_iomap_eof_want_preallocate( 267 xfs_mount_t *mp, 268 xfs_inode_t *ip, 269 xfs_off_t offset, 270 size_t count, 271 xfs_bmbt_irec_t *imap, 272 int nimaps, 273 int *prealloc) 274 { 275 xfs_fileoff_t start_fsb; 276 xfs_filblks_t count_fsb; 277 xfs_fsblock_t firstblock; 278 int n, error, imaps; 279 int found_delalloc = 0; 280 281 *prealloc = 0; 282 if (offset + count <= XFS_ISIZE(ip)) 283 return 0; 284 285 /* 286 * If the file is smaller than the minimum prealloc and we are using 287 * dynamic preallocation, don't do any preallocation at all as it is 288 * likely this is the only write to the file that is going to be done. 289 */ 290 if (!(mp->m_flags & XFS_MOUNT_DFLT_IOSIZE) && 291 XFS_ISIZE(ip) < XFS_FSB_TO_B(mp, mp->m_writeio_blocks)) 292 return 0; 293 294 /* 295 * If there are any real blocks past eof, then don't 296 * do any speculative allocation. 297 */ 298 start_fsb = XFS_B_TO_FSBT(mp, ((xfs_ufsize_t)(offset + count - 1))); 299 count_fsb = XFS_B_TO_FSB(mp, mp->m_super->s_maxbytes); 300 while (count_fsb > 0) { 301 imaps = nimaps; 302 firstblock = NULLFSBLOCK; 303 error = xfs_bmapi_read(ip, start_fsb, count_fsb, imap, &imaps, 304 0); 305 if (error) 306 return error; 307 for (n = 0; n < imaps; n++) { 308 if ((imap[n].br_startblock != HOLESTARTBLOCK) && 309 (imap[n].br_startblock != DELAYSTARTBLOCK)) 310 return 0; 311 start_fsb += imap[n].br_blockcount; 312 count_fsb -= imap[n].br_blockcount; 313 314 if (imap[n].br_startblock == DELAYSTARTBLOCK) 315 found_delalloc = 1; 316 } 317 } 318 if (!found_delalloc) 319 *prealloc = 1; 320 return 0; 321 } 322 323 /* 324 * Determine the initial size of the preallocation. We are beyond the current 325 * EOF here, but we need to take into account whether this is a sparse write or 326 * an extending write when determining the preallocation size. Hence we need to 327 * look up the extent that ends at the current write offset and use the result 328 * to determine the preallocation size. 329 * 330 * If the extent is a hole, then preallocation is essentially disabled. 331 * Otherwise we take the size of the preceeding data extent as the basis for the 332 * preallocation size. If the size of the extent is greater than half the 333 * maximum extent length, then use the current offset as the basis. This ensures 334 * that for large files the preallocation size always extends to MAXEXTLEN 335 * rather than falling short due to things like stripe unit/width alignment of 336 * real extents. 337 */ 338 STATIC xfs_fsblock_t 339 xfs_iomap_eof_prealloc_initial_size( 340 struct xfs_mount *mp, 341 struct xfs_inode *ip, 342 xfs_off_t offset, 343 xfs_bmbt_irec_t *imap, 344 int nimaps) 345 { 346 xfs_fileoff_t start_fsb; 347 int imaps = 1; 348 int error; 349 350 ASSERT(nimaps >= imaps); 351 352 /* if we are using a specific prealloc size, return now */ 353 if (mp->m_flags & XFS_MOUNT_DFLT_IOSIZE) 354 return 0; 355 356 /* If the file is small, then use the minimum prealloc */ 357 if (XFS_ISIZE(ip) < XFS_FSB_TO_B(mp, mp->m_dalign)) 358 return 0; 359 360 /* 361 * As we write multiple pages, the offset will always align to the 362 * start of a page and hence point to a hole at EOF. i.e. if the size is 363 * 4096 bytes, we only have one block at FSB 0, but XFS_B_TO_FSB(4096) 364 * will return FSB 1. Hence if there are blocks in the file, we want to 365 * point to the block prior to the EOF block and not the hole that maps 366 * directly at @offset. 367 */ 368 start_fsb = XFS_B_TO_FSB(mp, offset); 369 if (start_fsb) 370 start_fsb--; 371 error = xfs_bmapi_read(ip, start_fsb, 1, imap, &imaps, XFS_BMAPI_ENTIRE); 372 if (error) 373 return 0; 374 375 ASSERT(imaps == 1); 376 if (imap[0].br_startblock == HOLESTARTBLOCK) 377 return 0; 378 if (imap[0].br_blockcount <= (MAXEXTLEN >> 1)) 379 return imap[0].br_blockcount << 1; 380 return XFS_B_TO_FSB(mp, offset); 381 } 382 383 STATIC bool 384 xfs_quota_need_throttle( 385 struct xfs_inode *ip, 386 int type, 387 xfs_fsblock_t alloc_blocks) 388 { 389 struct xfs_dquot *dq = xfs_inode_dquot(ip, type); 390 391 if (!dq || !xfs_this_quota_on(ip->i_mount, type)) 392 return false; 393 394 /* no hi watermark, no throttle */ 395 if (!dq->q_prealloc_hi_wmark) 396 return false; 397 398 /* under the lo watermark, no throttle */ 399 if (dq->q_res_bcount + alloc_blocks < dq->q_prealloc_lo_wmark) 400 return false; 401 402 return true; 403 } 404 405 STATIC void 406 xfs_quota_calc_throttle( 407 struct xfs_inode *ip, 408 int type, 409 xfs_fsblock_t *qblocks, 410 int *qshift) 411 { 412 int64_t freesp; 413 int shift = 0; 414 struct xfs_dquot *dq = xfs_inode_dquot(ip, type); 415 416 /* over hi wmark, squash the prealloc completely */ 417 if (dq->q_res_bcount >= dq->q_prealloc_hi_wmark) { 418 *qblocks = 0; 419 return; 420 } 421 422 freesp = dq->q_prealloc_hi_wmark - dq->q_res_bcount; 423 if (freesp < dq->q_low_space[XFS_QLOWSP_5_PCNT]) { 424 shift = 2; 425 if (freesp < dq->q_low_space[XFS_QLOWSP_3_PCNT]) 426 shift += 2; 427 if (freesp < dq->q_low_space[XFS_QLOWSP_1_PCNT]) 428 shift += 2; 429 } 430 431 /* only overwrite the throttle values if we are more aggressive */ 432 if ((freesp >> shift) < (*qblocks >> *qshift)) { 433 *qblocks = freesp; 434 *qshift = shift; 435 } 436 } 437 438 /* 439 * If we don't have a user specified preallocation size, dynamically increase 440 * the preallocation size as the size of the file grows. Cap the maximum size 441 * at a single extent or less if the filesystem is near full. The closer the 442 * filesystem is to full, the smaller the maximum prealocation. 443 */ 444 STATIC xfs_fsblock_t 445 xfs_iomap_prealloc_size( 446 struct xfs_mount *mp, 447 struct xfs_inode *ip, 448 xfs_off_t offset, 449 struct xfs_bmbt_irec *imap, 450 int nimaps) 451 { 452 xfs_fsblock_t alloc_blocks = 0; 453 int shift = 0; 454 int64_t freesp; 455 xfs_fsblock_t qblocks; 456 int qshift = 0; 457 458 alloc_blocks = xfs_iomap_eof_prealloc_initial_size(mp, ip, offset, 459 imap, nimaps); 460 if (!alloc_blocks) 461 goto check_writeio; 462 qblocks = alloc_blocks; 463 464 /* 465 * MAXEXTLEN is not a power of two value but we round the prealloc down 466 * to the nearest power of two value after throttling. To prevent the 467 * round down from unconditionally reducing the maximum supported prealloc 468 * size, we round up first, apply appropriate throttling, round down and 469 * cap the value to MAXEXTLEN. 470 */ 471 alloc_blocks = XFS_FILEOFF_MIN(roundup_pow_of_two(MAXEXTLEN), 472 alloc_blocks); 473 474 xfs_icsb_sync_counters(mp, XFS_ICSB_LAZY_COUNT); 475 freesp = mp->m_sb.sb_fdblocks; 476 if (freesp < mp->m_low_space[XFS_LOWSP_5_PCNT]) { 477 shift = 2; 478 if (freesp < mp->m_low_space[XFS_LOWSP_4_PCNT]) 479 shift++; 480 if (freesp < mp->m_low_space[XFS_LOWSP_3_PCNT]) 481 shift++; 482 if (freesp < mp->m_low_space[XFS_LOWSP_2_PCNT]) 483 shift++; 484 if (freesp < mp->m_low_space[XFS_LOWSP_1_PCNT]) 485 shift++; 486 } 487 488 /* 489 * Check each quota to cap the prealloc size and provide a shift 490 * value to throttle with. 491 */ 492 if (xfs_quota_need_throttle(ip, XFS_DQ_USER, alloc_blocks)) 493 xfs_quota_calc_throttle(ip, XFS_DQ_USER, &qblocks, &qshift); 494 if (xfs_quota_need_throttle(ip, XFS_DQ_GROUP, alloc_blocks)) 495 xfs_quota_calc_throttle(ip, XFS_DQ_GROUP, &qblocks, &qshift); 496 if (xfs_quota_need_throttle(ip, XFS_DQ_PROJ, alloc_blocks)) 497 xfs_quota_calc_throttle(ip, XFS_DQ_PROJ, &qblocks, &qshift); 498 499 /* 500 * The final prealloc size is set to the minimum of free space available 501 * in each of the quotas and the overall filesystem. 502 * 503 * The shift throttle value is set to the maximum value as determined by 504 * the global low free space values and per-quota low free space values. 505 */ 506 alloc_blocks = MIN(alloc_blocks, qblocks); 507 shift = MAX(shift, qshift); 508 509 if (shift) 510 alloc_blocks >>= shift; 511 /* 512 * rounddown_pow_of_two() returns an undefined result if we pass in 513 * alloc_blocks = 0. 514 */ 515 if (alloc_blocks) 516 alloc_blocks = rounddown_pow_of_two(alloc_blocks); 517 if (alloc_blocks > MAXEXTLEN) 518 alloc_blocks = MAXEXTLEN; 519 520 /* 521 * If we are still trying to allocate more space than is 522 * available, squash the prealloc hard. This can happen if we 523 * have a large file on a small filesystem and the above 524 * lowspace thresholds are smaller than MAXEXTLEN. 525 */ 526 while (alloc_blocks && alloc_blocks >= freesp) 527 alloc_blocks >>= 4; 528 529 check_writeio: 530 if (alloc_blocks < mp->m_writeio_blocks) 531 alloc_blocks = mp->m_writeio_blocks; 532 533 trace_xfs_iomap_prealloc_size(ip, alloc_blocks, shift, 534 mp->m_writeio_blocks); 535 536 return alloc_blocks; 537 } 538 539 int 540 xfs_iomap_write_delay( 541 xfs_inode_t *ip, 542 xfs_off_t offset, 543 size_t count, 544 xfs_bmbt_irec_t *ret_imap) 545 { 546 xfs_mount_t *mp = ip->i_mount; 547 xfs_fileoff_t offset_fsb; 548 xfs_fileoff_t last_fsb; 549 xfs_off_t aligned_offset; 550 xfs_fileoff_t ioalign; 551 xfs_extlen_t extsz; 552 int nimaps; 553 xfs_bmbt_irec_t imap[XFS_WRITE_IMAPS]; 554 int prealloc; 555 int error; 556 557 ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL)); 558 559 /* 560 * Make sure that the dquots are there. This doesn't hold 561 * the ilock across a disk read. 562 */ 563 error = xfs_qm_dqattach_locked(ip, 0); 564 if (error) 565 return XFS_ERROR(error); 566 567 extsz = xfs_get_extsz_hint(ip); 568 offset_fsb = XFS_B_TO_FSBT(mp, offset); 569 570 error = xfs_iomap_eof_want_preallocate(mp, ip, offset, count, 571 imap, XFS_WRITE_IMAPS, &prealloc); 572 if (error) 573 return error; 574 575 retry: 576 if (prealloc) { 577 xfs_fsblock_t alloc_blocks; 578 579 alloc_blocks = xfs_iomap_prealloc_size(mp, ip, offset, imap, 580 XFS_WRITE_IMAPS); 581 582 aligned_offset = XFS_WRITEIO_ALIGN(mp, (offset + count - 1)); 583 ioalign = XFS_B_TO_FSBT(mp, aligned_offset); 584 last_fsb = ioalign + alloc_blocks; 585 } else { 586 last_fsb = XFS_B_TO_FSB(mp, ((xfs_ufsize_t)(offset + count))); 587 } 588 589 if (prealloc || extsz) { 590 error = xfs_iomap_eof_align_last_fsb(mp, ip, extsz, &last_fsb); 591 if (error) 592 return error; 593 } 594 595 /* 596 * Make sure preallocation does not create extents beyond the range we 597 * actually support in this filesystem. 598 */ 599 if (last_fsb > XFS_B_TO_FSB(mp, mp->m_super->s_maxbytes)) 600 last_fsb = XFS_B_TO_FSB(mp, mp->m_super->s_maxbytes); 601 602 ASSERT(last_fsb > offset_fsb); 603 604 nimaps = XFS_WRITE_IMAPS; 605 error = xfs_bmapi_delay(ip, offset_fsb, last_fsb - offset_fsb, 606 imap, &nimaps, XFS_BMAPI_ENTIRE); 607 switch (error) { 608 case 0: 609 case ENOSPC: 610 case EDQUOT: 611 break; 612 default: 613 return XFS_ERROR(error); 614 } 615 616 /* 617 * If bmapi returned us nothing, we got either ENOSPC or EDQUOT. Retry 618 * without EOF preallocation. 619 */ 620 if (nimaps == 0) { 621 trace_xfs_delalloc_enospc(ip, offset, count); 622 if (prealloc) { 623 prealloc = 0; 624 error = 0; 625 goto retry; 626 } 627 return XFS_ERROR(error ? error : ENOSPC); 628 } 629 630 if (!(imap[0].br_startblock || XFS_IS_REALTIME_INODE(ip))) 631 return xfs_alert_fsblock_zero(ip, &imap[0]); 632 633 /* 634 * Tag the inode as speculatively preallocated so we can reclaim this 635 * space on demand, if necessary. 636 */ 637 if (prealloc) 638 xfs_inode_set_eofblocks_tag(ip); 639 640 *ret_imap = imap[0]; 641 return 0; 642 } 643 644 /* 645 * Pass in a delayed allocate extent, convert it to real extents; 646 * return to the caller the extent we create which maps on top of 647 * the originating callers request. 648 * 649 * Called without a lock on the inode. 650 * 651 * We no longer bother to look at the incoming map - all we have to 652 * guarantee is that whatever we allocate fills the required range. 653 */ 654 int 655 xfs_iomap_write_allocate( 656 xfs_inode_t *ip, 657 xfs_off_t offset, 658 size_t count, 659 xfs_bmbt_irec_t *imap) 660 { 661 xfs_mount_t *mp = ip->i_mount; 662 xfs_fileoff_t offset_fsb, last_block; 663 xfs_fileoff_t end_fsb, map_start_fsb; 664 xfs_fsblock_t first_block; 665 xfs_bmap_free_t free_list; 666 xfs_filblks_t count_fsb; 667 xfs_trans_t *tp; 668 int nimaps, committed; 669 int error = 0; 670 int nres; 671 672 /* 673 * Make sure that the dquots are there. 674 */ 675 error = xfs_qm_dqattach(ip, 0); 676 if (error) 677 return XFS_ERROR(error); 678 679 offset_fsb = XFS_B_TO_FSBT(mp, offset); 680 count_fsb = imap->br_blockcount; 681 map_start_fsb = imap->br_startoff; 682 683 XFS_STATS_ADD(xs_xstrat_bytes, XFS_FSB_TO_B(mp, count_fsb)); 684 685 while (count_fsb != 0) { 686 /* 687 * Set up a transaction with which to allocate the 688 * backing store for the file. Do allocations in a 689 * loop until we get some space in the range we are 690 * interested in. The other space that might be allocated 691 * is in the delayed allocation extent on which we sit 692 * but before our buffer starts. 693 */ 694 695 nimaps = 0; 696 while (nimaps == 0) { 697 tp = xfs_trans_alloc(mp, XFS_TRANS_STRAT_WRITE); 698 tp->t_flags |= XFS_TRANS_RESERVE; 699 nres = XFS_EXTENTADD_SPACE_RES(mp, XFS_DATA_FORK); 700 error = xfs_trans_reserve(tp, &M_RES(mp)->tr_write, 701 nres, 0); 702 if (error) { 703 xfs_trans_cancel(tp, 0); 704 return XFS_ERROR(error); 705 } 706 xfs_ilock(ip, XFS_ILOCK_EXCL); 707 xfs_trans_ijoin(tp, ip, 0); 708 709 xfs_bmap_init(&free_list, &first_block); 710 711 /* 712 * it is possible that the extents have changed since 713 * we did the read call as we dropped the ilock for a 714 * while. We have to be careful about truncates or hole 715 * punchs here - we are not allowed to allocate 716 * non-delalloc blocks here. 717 * 718 * The only protection against truncation is the pages 719 * for the range we are being asked to convert are 720 * locked and hence a truncate will block on them 721 * first. 722 * 723 * As a result, if we go beyond the range we really 724 * need and hit an delalloc extent boundary followed by 725 * a hole while we have excess blocks in the map, we 726 * will fill the hole incorrectly and overrun the 727 * transaction reservation. 728 * 729 * Using a single map prevents this as we are forced to 730 * check each map we look for overlap with the desired 731 * range and abort as soon as we find it. Also, given 732 * that we only return a single map, having one beyond 733 * what we can return is probably a bit silly. 734 * 735 * We also need to check that we don't go beyond EOF; 736 * this is a truncate optimisation as a truncate sets 737 * the new file size before block on the pages we 738 * currently have locked under writeback. Because they 739 * are about to be tossed, we don't need to write them 740 * back.... 741 */ 742 nimaps = 1; 743 end_fsb = XFS_B_TO_FSB(mp, XFS_ISIZE(ip)); 744 error = xfs_bmap_last_offset(NULL, ip, &last_block, 745 XFS_DATA_FORK); 746 if (error) 747 goto trans_cancel; 748 749 last_block = XFS_FILEOFF_MAX(last_block, end_fsb); 750 if ((map_start_fsb + count_fsb) > last_block) { 751 count_fsb = last_block - map_start_fsb; 752 if (count_fsb == 0) { 753 error = EAGAIN; 754 goto trans_cancel; 755 } 756 } 757 758 /* 759 * From this point onwards we overwrite the imap 760 * pointer that the caller gave to us. 761 */ 762 error = xfs_bmapi_write(tp, ip, map_start_fsb, 763 count_fsb, 764 XFS_BMAPI_STACK_SWITCH, 765 &first_block, 1, 766 imap, &nimaps, &free_list); 767 if (error) 768 goto trans_cancel; 769 770 error = xfs_bmap_finish(&tp, &free_list, &committed); 771 if (error) 772 goto trans_cancel; 773 774 error = xfs_trans_commit(tp, XFS_TRANS_RELEASE_LOG_RES); 775 if (error) 776 goto error0; 777 778 xfs_iunlock(ip, XFS_ILOCK_EXCL); 779 } 780 781 /* 782 * See if we were able to allocate an extent that 783 * covers at least part of the callers request 784 */ 785 if (!(imap->br_startblock || XFS_IS_REALTIME_INODE(ip))) 786 return xfs_alert_fsblock_zero(ip, imap); 787 788 if ((offset_fsb >= imap->br_startoff) && 789 (offset_fsb < (imap->br_startoff + 790 imap->br_blockcount))) { 791 XFS_STATS_INC(xs_xstrat_quick); 792 return 0; 793 } 794 795 /* 796 * So far we have not mapped the requested part of the 797 * file, just surrounding data, try again. 798 */ 799 count_fsb -= imap->br_blockcount; 800 map_start_fsb = imap->br_startoff + imap->br_blockcount; 801 } 802 803 trans_cancel: 804 xfs_bmap_cancel(&free_list); 805 xfs_trans_cancel(tp, XFS_TRANS_RELEASE_LOG_RES | XFS_TRANS_ABORT); 806 error0: 807 xfs_iunlock(ip, XFS_ILOCK_EXCL); 808 return XFS_ERROR(error); 809 } 810 811 int 812 xfs_iomap_write_unwritten( 813 xfs_inode_t *ip, 814 xfs_off_t offset, 815 size_t count) 816 { 817 xfs_mount_t *mp = ip->i_mount; 818 xfs_fileoff_t offset_fsb; 819 xfs_filblks_t count_fsb; 820 xfs_filblks_t numblks_fsb; 821 xfs_fsblock_t firstfsb; 822 int nimaps; 823 xfs_trans_t *tp; 824 xfs_bmbt_irec_t imap; 825 xfs_bmap_free_t free_list; 826 xfs_fsize_t i_size; 827 uint resblks; 828 int committed; 829 int error; 830 831 trace_xfs_unwritten_convert(ip, offset, count); 832 833 offset_fsb = XFS_B_TO_FSBT(mp, offset); 834 count_fsb = XFS_B_TO_FSB(mp, (xfs_ufsize_t)offset + count); 835 count_fsb = (xfs_filblks_t)(count_fsb - offset_fsb); 836 837 /* 838 * Reserve enough blocks in this transaction for two complete extent 839 * btree splits. We may be converting the middle part of an unwritten 840 * extent and in this case we will insert two new extents in the btree 841 * each of which could cause a full split. 842 * 843 * This reservation amount will be used in the first call to 844 * xfs_bmbt_split() to select an AG with enough space to satisfy the 845 * rest of the operation. 846 */ 847 resblks = XFS_DIOSTRAT_SPACE_RES(mp, 0) << 1; 848 849 do { 850 /* 851 * set up a transaction to convert the range of extents 852 * from unwritten to real. Do allocations in a loop until 853 * we have covered the range passed in. 854 * 855 * Note that we open code the transaction allocation here 856 * to pass KM_NOFS--we can't risk to recursing back into 857 * the filesystem here as we might be asked to write out 858 * the same inode that we complete here and might deadlock 859 * on the iolock. 860 */ 861 sb_start_intwrite(mp->m_super); 862 tp = _xfs_trans_alloc(mp, XFS_TRANS_STRAT_WRITE, KM_NOFS); 863 tp->t_flags |= XFS_TRANS_RESERVE | XFS_TRANS_FREEZE_PROT; 864 error = xfs_trans_reserve(tp, &M_RES(mp)->tr_write, 865 resblks, 0); 866 if (error) { 867 xfs_trans_cancel(tp, 0); 868 return XFS_ERROR(error); 869 } 870 871 xfs_ilock(ip, XFS_ILOCK_EXCL); 872 xfs_trans_ijoin(tp, ip, 0); 873 874 /* 875 * Modify the unwritten extent state of the buffer. 876 */ 877 xfs_bmap_init(&free_list, &firstfsb); 878 nimaps = 1; 879 error = xfs_bmapi_write(tp, ip, offset_fsb, count_fsb, 880 XFS_BMAPI_CONVERT, &firstfsb, 881 1, &imap, &nimaps, &free_list); 882 if (error) 883 goto error_on_bmapi_transaction; 884 885 /* 886 * Log the updated inode size as we go. We have to be careful 887 * to only log it up to the actual write offset if it is 888 * halfway into a block. 889 */ 890 i_size = XFS_FSB_TO_B(mp, offset_fsb + count_fsb); 891 if (i_size > offset + count) 892 i_size = offset + count; 893 894 i_size = xfs_new_eof(ip, i_size); 895 if (i_size) { 896 ip->i_d.di_size = i_size; 897 xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE); 898 } 899 900 error = xfs_bmap_finish(&tp, &free_list, &committed); 901 if (error) 902 goto error_on_bmapi_transaction; 903 904 error = xfs_trans_commit(tp, XFS_TRANS_RELEASE_LOG_RES); 905 xfs_iunlock(ip, XFS_ILOCK_EXCL); 906 if (error) 907 return XFS_ERROR(error); 908 909 if (!(imap.br_startblock || XFS_IS_REALTIME_INODE(ip))) 910 return xfs_alert_fsblock_zero(ip, &imap); 911 912 if ((numblks_fsb = imap.br_blockcount) == 0) { 913 /* 914 * The numblks_fsb value should always get 915 * smaller, otherwise the loop is stuck. 916 */ 917 ASSERT(imap.br_blockcount); 918 break; 919 } 920 offset_fsb += numblks_fsb; 921 count_fsb -= numblks_fsb; 922 } while (count_fsb > 0); 923 924 return 0; 925 926 error_on_bmapi_transaction: 927 xfs_bmap_cancel(&free_list); 928 xfs_trans_cancel(tp, (XFS_TRANS_RELEASE_LOG_RES | XFS_TRANS_ABORT)); 929 xfs_iunlock(ip, XFS_ILOCK_EXCL); 930 return XFS_ERROR(error); 931 } 932