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