1 /* 2 * CDDL HEADER START 3 * 4 * The contents of this file are subject to the terms of the 5 * Common Development and Distribution License (the "License"). 6 * You may not use this file except in compliance with the License. 7 * 8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 9 * or http://www.opensolaris.org/os/licensing. 10 * See the License for the specific language governing permissions 11 * and limitations under the License. 12 * 13 * When distributing Covered Code, include this CDDL HEADER in each 14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 15 * If applicable, add the following below this CDDL HEADER, with the 16 * fields enclosed by brackets "[]" replaced with your own identifying 17 * information: Portions Copyright [yyyy] [name of copyright owner] 18 * 19 * CDDL HEADER END 20 */ 21 /* 22 * Copyright 2009 Sun Microsystems, Inc. All rights reserved. 23 * Use is subject to license terms. 24 */ 25 26 /* Copyright (c) 1983, 1984, 1985, 1986, 1987, 1988, 1989 AT&T */ 27 /* All Rights Reserved */ 28 29 /* 30 * Portions of this source code were derived from Berkeley 4.3 BSD 31 * under license from the Regents of the University of California. 32 */ 33 34 #include <sys/types.h> 35 #include <sys/t_lock.h> 36 #include <sys/param.h> 37 #include <sys/time.h> 38 #include <sys/systm.h> 39 #include <sys/sysmacros.h> 40 #include <sys/resource.h> 41 #include <sys/signal.h> 42 #include <sys/cred.h> 43 #include <sys/user.h> 44 #include <sys/buf.h> 45 #include <sys/vfs.h> 46 #include <sys/vnode.h> 47 #include <sys/proc.h> 48 #include <sys/disp.h> 49 #include <sys/file.h> 50 #include <sys/fcntl.h> 51 #include <sys/flock.h> 52 #include <sys/kmem.h> 53 #include <sys/uio.h> 54 #include <sys/dnlc.h> 55 #include <sys/conf.h> 56 #include <sys/mman.h> 57 #include <sys/pathname.h> 58 #include <sys/debug.h> 59 #include <sys/vmsystm.h> 60 #include <sys/cmn_err.h> 61 #include <sys/filio.h> 62 #include <sys/atomic.h> 63 64 #include <sys/fssnap_if.h> 65 #include <sys/fs/ufs_fs.h> 66 #include <sys/fs/ufs_lockfs.h> 67 #include <sys/fs/ufs_filio.h> 68 #include <sys/fs/ufs_inode.h> 69 #include <sys/fs/ufs_fsdir.h> 70 #include <sys/fs/ufs_quota.h> 71 #include <sys/fs/ufs_trans.h> 72 #include <sys/fs/ufs_panic.h> 73 #include <sys/dirent.h> /* must be AFTER <sys/fs/fsdir.h>! */ 74 #include <sys/errno.h> 75 76 #include <sys/filio.h> /* _FIOIO */ 77 78 #include <vm/hat.h> 79 #include <vm/page.h> 80 #include <vm/pvn.h> 81 #include <vm/as.h> 82 #include <vm/seg.h> 83 #include <vm/seg_map.h> 84 #include <vm/seg_vn.h> 85 #include <vm/seg_kmem.h> 86 #include <vm/rm.h> 87 #include <sys/swap.h> 88 #include <sys/epm.h> 89 90 #include <fs/fs_subr.h> 91 92 static void *ufs_directio_zero_buf; 93 static int ufs_directio_zero_len = 8192; 94 95 int ufs_directio_enabled = 1; /* feature is enabled */ 96 97 /* 98 * for kstats reader 99 */ 100 struct ufs_directio_kstats { 101 kstat_named_t logical_reads; 102 kstat_named_t phys_reads; 103 kstat_named_t hole_reads; 104 kstat_named_t nread; 105 kstat_named_t logical_writes; 106 kstat_named_t phys_writes; 107 kstat_named_t nwritten; 108 kstat_named_t nflushes; 109 } ufs_directio_kstats = { 110 { "logical_reads", KSTAT_DATA_UINT64 }, 111 { "phys_reads", KSTAT_DATA_UINT64 }, 112 { "hole_reads", KSTAT_DATA_UINT64 }, 113 { "nread", KSTAT_DATA_UINT64 }, 114 { "logical_writes", KSTAT_DATA_UINT64 }, 115 { "phys_writes", KSTAT_DATA_UINT64 }, 116 { "nwritten", KSTAT_DATA_UINT64 }, 117 { "nflushes", KSTAT_DATA_UINT64 }, 118 }; 119 120 kstat_t *ufs_directio_kstatsp; 121 122 /* 123 * use kmem_cache_create for direct-physio buffers. This has shown 124 * a better cache distribution compared to buffers on the 125 * stack. It also avoids semaphore construction/deconstruction 126 * per request 127 */ 128 struct directio_buf { 129 struct directio_buf *next; 130 char *addr; 131 size_t nbytes; 132 struct buf buf; 133 }; 134 static struct kmem_cache *directio_buf_cache; 135 136 137 /* ARGSUSED */ 138 static int 139 directio_buf_constructor(void *dbp, void *cdrarg, int kmflags) 140 { 141 bioinit((struct buf *)&((struct directio_buf *)dbp)->buf); 142 return (0); 143 } 144 145 /* ARGSUSED */ 146 static void 147 directio_buf_destructor(void *dbp, void *cdrarg) 148 { 149 biofini((struct buf *)&((struct directio_buf *)dbp)->buf); 150 } 151 152 void 153 directio_bufs_init(void) 154 { 155 directio_buf_cache = kmem_cache_create("directio_buf_cache", 156 sizeof (struct directio_buf), 0, 157 directio_buf_constructor, directio_buf_destructor, 158 NULL, NULL, NULL, 0); 159 } 160 161 void 162 ufs_directio_init(void) 163 { 164 /* 165 * kstats 166 */ 167 ufs_directio_kstatsp = kstat_create("ufs", 0, 168 "directio", "ufs", KSTAT_TYPE_NAMED, 169 sizeof (ufs_directio_kstats) / sizeof (kstat_named_t), 170 KSTAT_FLAG_VIRTUAL | KSTAT_FLAG_WRITABLE); 171 if (ufs_directio_kstatsp) { 172 ufs_directio_kstatsp->ks_data = (void *)&ufs_directio_kstats; 173 kstat_install(ufs_directio_kstatsp); 174 } 175 /* 176 * kzero is broken so we have to use a private buf of zeroes 177 */ 178 ufs_directio_zero_buf = kmem_zalloc(ufs_directio_zero_len, KM_SLEEP); 179 directio_bufs_init(); 180 } 181 182 /* 183 * Wait for the first direct IO operation to finish 184 */ 185 static int 186 directio_wait_one(struct directio_buf *dbp, long *bytes_iop) 187 { 188 buf_t *bp; 189 int error; 190 191 /* 192 * Wait for IO to finish 193 */ 194 bp = &dbp->buf; 195 error = biowait(bp); 196 197 /* 198 * bytes_io will be used to figure out a resid 199 * for the caller. The resid is approximated by reporting 200 * the bytes following the first failed IO as the residual. 201 * 202 * I am cautious about using b_resid because I 203 * am not sure how well the disk drivers maintain it. 204 */ 205 if (error) 206 if (bp->b_resid) 207 *bytes_iop = bp->b_bcount - bp->b_resid; 208 else 209 *bytes_iop = 0; 210 else 211 *bytes_iop += bp->b_bcount; 212 /* 213 * Release direct IO resources 214 */ 215 bp->b_flags &= ~(B_BUSY|B_WANTED|B_PHYS|B_SHADOW); 216 kmem_cache_free(directio_buf_cache, dbp); 217 return (error); 218 } 219 220 /* 221 * Wait for all of the direct IO operations to finish 222 */ 223 224 uint32_t ufs_directio_drop_kpri = 0; /* enable kpri hack */ 225 226 static int 227 directio_wait(struct directio_buf *tail, long *bytes_iop) 228 { 229 int error = 0, newerror; 230 struct directio_buf *dbp; 231 uint_t kpri_req_save; 232 233 /* 234 * The linked list of directio buf structures is maintained 235 * in reverse order (tail->last request->penultimate request->...) 236 */ 237 /* 238 * This is the k_pri_req hack. Large numbers of threads 239 * sleeping with kernel priority will cause scheduler thrashing 240 * on an MP machine. This can be seen running Oracle using 241 * directio to ufs files. Sleep at normal priority here to 242 * more closely mimic physio to a device partition. This 243 * workaround is disabled by default as a niced thread could 244 * be starved from running while holding i_rwlock and i_contents. 245 */ 246 if (ufs_directio_drop_kpri) { 247 kpri_req_save = curthread->t_kpri_req; 248 curthread->t_kpri_req = 0; 249 } 250 while ((dbp = tail) != NULL) { 251 tail = dbp->next; 252 newerror = directio_wait_one(dbp, bytes_iop); 253 if (error == 0) 254 error = newerror; 255 } 256 if (ufs_directio_drop_kpri) 257 curthread->t_kpri_req = kpri_req_save; 258 return (error); 259 } 260 /* 261 * Initiate direct IO request 262 */ 263 static void 264 directio_start(struct ufsvfs *ufsvfsp, struct inode *ip, size_t nbytes, 265 offset_t offset, char *addr, enum seg_rw rw, struct proc *procp, 266 struct directio_buf **tailp, page_t **pplist) 267 { 268 buf_t *bp; 269 struct directio_buf *dbp; 270 271 /* 272 * Allocate a directio buf header 273 * Note - list is maintained in reverse order. 274 * directio_wait_one() depends on this fact when 275 * adjusting the ``bytes_io'' param. bytes_io 276 * is used to compute a residual in the case of error. 277 */ 278 dbp = kmem_cache_alloc(directio_buf_cache, KM_SLEEP); 279 dbp->next = *tailp; 280 *tailp = dbp; 281 282 /* 283 * Initialize buf header 284 */ 285 dbp->addr = addr; 286 dbp->nbytes = nbytes; 287 bp = &dbp->buf; 288 bp->b_edev = ip->i_dev; 289 bp->b_lblkno = btodt(offset); 290 bp->b_bcount = nbytes; 291 bp->b_un.b_addr = addr; 292 bp->b_proc = procp; 293 bp->b_file = ip->i_vnode; 294 295 /* 296 * Note that S_WRITE implies B_READ and vice versa: a read(2) 297 * will B_READ data from the filesystem and S_WRITE it into 298 * the user's buffer; a write(2) will S_READ data from the 299 * user's buffer and B_WRITE it to the filesystem. 300 */ 301 if (rw == S_WRITE) { 302 bp->b_flags = B_BUSY | B_PHYS | B_READ; 303 ufs_directio_kstats.phys_reads.value.ui64++; 304 ufs_directio_kstats.nread.value.ui64 += nbytes; 305 } else { 306 bp->b_flags = B_BUSY | B_PHYS | B_WRITE; 307 ufs_directio_kstats.phys_writes.value.ui64++; 308 ufs_directio_kstats.nwritten.value.ui64 += nbytes; 309 } 310 bp->b_shadow = pplist; 311 if (pplist != NULL) 312 bp->b_flags |= B_SHADOW; 313 314 /* 315 * Issue I/O request. 316 */ 317 ufsvfsp->vfs_iotstamp = lbolt; 318 if (ufsvfsp->vfs_snapshot) 319 fssnap_strategy(&ufsvfsp->vfs_snapshot, bp); 320 else 321 (void) bdev_strategy(bp); 322 323 if (rw == S_WRITE) 324 lwp_stat_update(LWP_STAT_OUBLK, 1); 325 else 326 lwp_stat_update(LWP_STAT_INBLK, 1); 327 328 } 329 330 uint32_t ufs_shared_writes; /* writes done w/ lock shared */ 331 uint32_t ufs_cur_writes; /* # concurrent writes */ 332 uint32_t ufs_maxcur_writes; /* high water concurrent writes */ 333 uint32_t ufs_posix_hits; /* writes done /w lock excl. */ 334 335 /* 336 * Force POSIX syncronous data integrity on all writes for testing. 337 */ 338 uint32_t ufs_force_posix_sdi = 0; 339 340 /* 341 * Direct Write 342 */ 343 344 int 345 ufs_directio_write(struct inode *ip, uio_t *arg_uio, int ioflag, int rewrite, 346 cred_t *cr, int *statusp) 347 { 348 long resid, bytes_written; 349 u_offset_t size, uoff; 350 uio_t *uio = arg_uio; 351 rlim64_t limit = uio->uio_llimit; 352 int on, n, error, newerror, len, has_holes; 353 daddr_t bn; 354 size_t nbytes; 355 struct fs *fs; 356 vnode_t *vp; 357 iovec_t *iov; 358 struct ufsvfs *ufsvfsp = ip->i_ufsvfs; 359 struct proc *procp; 360 struct as *as; 361 struct directio_buf *tail; 362 int exclusive, ncur, bmap_peek; 363 uio_t copy_uio; 364 iovec_t copy_iov; 365 char *copy_base; 366 long copy_resid; 367 368 /* 369 * assume that directio isn't possible (normal case) 370 */ 371 *statusp = DIRECTIO_FAILURE; 372 373 /* 374 * Don't go direct 375 */ 376 if (ufs_directio_enabled == 0) 377 return (0); 378 379 /* 380 * mapped file; nevermind 381 */ 382 if (ip->i_mapcnt) 383 return (0); 384 385 /* 386 * CAN WE DO DIRECT IO? 387 */ 388 uoff = uio->uio_loffset; 389 resid = uio->uio_resid; 390 391 /* 392 * beyond limit 393 */ 394 if (uoff + resid > limit) 395 return (0); 396 397 /* 398 * must be sector aligned 399 */ 400 if ((uoff & (u_offset_t)(DEV_BSIZE - 1)) || (resid & (DEV_BSIZE - 1))) 401 return (0); 402 403 /* 404 * SHOULD WE DO DIRECT IO? 405 */ 406 size = ip->i_size; 407 has_holes = -1; 408 409 /* 410 * only on regular files; no metadata 411 */ 412 if (((ip->i_mode & IFMT) != IFREG) || ip->i_ufsvfs->vfs_qinod == ip) 413 return (0); 414 415 /* 416 * Synchronous, allocating writes run very slow in Direct-Mode 417 * XXX - can be fixed with bmap_write changes for large writes!!! 418 * XXX - can be fixed for updates to "almost-full" files 419 * XXX - WARNING - system hangs if bmap_write() has to 420 * allocate lots of pages since pageout 421 * suspends on locked inode 422 */ 423 if (!rewrite && (ip->i_flag & ISYNC)) { 424 if ((uoff + resid) > size) 425 return (0); 426 has_holes = bmap_has_holes(ip); 427 if (has_holes) 428 return (0); 429 } 430 431 /* 432 * Each iovec must be short aligned and sector aligned. If 433 * one is not, then kmem_alloc a new buffer and copy all of 434 * the smaller buffers into the new buffer. This new 435 * buffer will be short aligned and sector aligned. 436 */ 437 iov = uio->uio_iov; 438 nbytes = uio->uio_iovcnt; 439 while (nbytes--) { 440 if (((uint_t)iov->iov_len & (DEV_BSIZE - 1)) != 0 || 441 (intptr_t)(iov->iov_base) & 1) { 442 copy_resid = uio->uio_resid; 443 copy_base = kmem_alloc(copy_resid, KM_NOSLEEP); 444 if (copy_base == NULL) 445 return (0); 446 copy_iov.iov_base = copy_base; 447 copy_iov.iov_len = copy_resid; 448 copy_uio.uio_iov = ©_iov; 449 copy_uio.uio_iovcnt = 1; 450 copy_uio.uio_segflg = UIO_SYSSPACE; 451 copy_uio.uio_extflg = UIO_COPY_DEFAULT; 452 copy_uio.uio_loffset = uio->uio_loffset; 453 copy_uio.uio_resid = uio->uio_resid; 454 copy_uio.uio_llimit = uio->uio_llimit; 455 error = uiomove(copy_base, copy_resid, UIO_WRITE, uio); 456 if (error) { 457 kmem_free(copy_base, copy_resid); 458 return (0); 459 } 460 uio = ©_uio; 461 break; 462 } 463 iov++; 464 } 465 466 /* 467 * From here on down, all error exits must go to errout and 468 * not simply return a 0. 469 */ 470 471 /* 472 * DIRECTIO 473 */ 474 475 fs = ip->i_fs; 476 477 /* 478 * POSIX check. If attempting a concurrent re-write, make sure 479 * that this will be a single request to the driver to meet 480 * POSIX synchronous data integrity requirements. 481 */ 482 bmap_peek = 0; 483 if (rewrite && ((ioflag & FDSYNC) || ufs_force_posix_sdi)) { 484 int upgrade = 0; 485 486 /* check easy conditions first */ 487 if (uio->uio_iovcnt != 1 || resid > ufsvfsp->vfs_ioclustsz) { 488 upgrade = 1; 489 } else { 490 /* now look for contiguous allocation */ 491 len = (ssize_t)blkroundup(fs, resid); 492 error = bmap_read(ip, uoff, &bn, &len); 493 if (error || bn == UFS_HOLE || len == 0) 494 goto errout; 495 /* save a call to bmap_read later */ 496 bmap_peek = 1; 497 if (len < resid) 498 upgrade = 1; 499 } 500 if (upgrade) { 501 rw_exit(&ip->i_contents); 502 rw_enter(&ip->i_contents, RW_WRITER); 503 ufs_posix_hits++; 504 } 505 } 506 507 508 /* 509 * allocate space 510 */ 511 512 /* 513 * If attempting a re-write, there is no allocation to do. 514 * bmap_write would trip an ASSERT if i_contents is held shared. 515 */ 516 if (rewrite) 517 goto skip_alloc; 518 519 do { 520 on = (int)blkoff(fs, uoff); 521 n = (int)MIN(fs->fs_bsize - on, resid); 522 if ((uoff + n) > ip->i_size) { 523 error = bmap_write(ip, uoff, (int)(on + n), 524 (int)(uoff & (offset_t)MAXBOFFSET) == 0, 525 NULL, cr); 526 /* Caller is responsible for updating i_seq if needed */ 527 if (error) 528 break; 529 ip->i_size = uoff + n; 530 ip->i_flag |= IATTCHG; 531 } else if (n == MAXBSIZE) { 532 error = bmap_write(ip, uoff, (int)(on + n), 533 BI_ALLOC_ONLY, NULL, cr); 534 /* Caller is responsible for updating i_seq if needed */ 535 } else { 536 if (has_holes < 0) 537 has_holes = bmap_has_holes(ip); 538 if (has_holes) { 539 uint_t blk_size; 540 u_offset_t offset; 541 542 offset = uoff & (offset_t)fs->fs_bmask; 543 blk_size = (int)blksize(fs, ip, 544 (daddr_t)lblkno(fs, offset)); 545 error = bmap_write(ip, uoff, blk_size, 546 BI_NORMAL, NULL, cr); 547 /* 548 * Caller is responsible for updating 549 * i_seq if needed 550 */ 551 } else 552 error = 0; 553 } 554 if (error) 555 break; 556 uoff += n; 557 resid -= n; 558 /* 559 * if file has grown larger than 2GB, set flag 560 * in superblock if not already set 561 */ 562 if ((ip->i_size > MAXOFF32_T) && 563 !(fs->fs_flags & FSLARGEFILES)) { 564 ASSERT(ufsvfsp->vfs_lfflags & UFS_LARGEFILES); 565 mutex_enter(&ufsvfsp->vfs_lock); 566 fs->fs_flags |= FSLARGEFILES; 567 ufs_sbwrite(ufsvfsp); 568 mutex_exit(&ufsvfsp->vfs_lock); 569 } 570 } while (resid); 571 572 if (error) { 573 /* 574 * restore original state 575 */ 576 if (resid) { 577 if (size == ip->i_size) 578 goto errout; 579 (void) ufs_itrunc(ip, size, 0, cr); 580 } 581 /* 582 * try non-directio path 583 */ 584 goto errout; 585 } 586 skip_alloc: 587 588 /* 589 * get rid of cached pages 590 */ 591 vp = ITOV(ip); 592 exclusive = rw_write_held(&ip->i_contents); 593 if (vn_has_cached_data(vp)) { 594 if (!exclusive) { 595 /* 596 * Still holding i_rwlock, so no allocations 597 * can happen after dropping contents. 598 */ 599 rw_exit(&ip->i_contents); 600 rw_enter(&ip->i_contents, RW_WRITER); 601 } 602 (void) VOP_PUTPAGE(vp, (offset_t)0, (size_t)0, 603 B_INVAL, cr, NULL); 604 if (vn_has_cached_data(vp)) 605 goto errout; 606 if (!exclusive) 607 rw_downgrade(&ip->i_contents); 608 ufs_directio_kstats.nflushes.value.ui64++; 609 } 610 611 /* 612 * Direct Writes 613 */ 614 615 if (!exclusive) { 616 ufs_shared_writes++; 617 ncur = atomic_add_32_nv(&ufs_cur_writes, 1); 618 if (ncur > ufs_maxcur_writes) 619 ufs_maxcur_writes = ncur; 620 } 621 622 /* 623 * proc and as are for VM operations in directio_start() 624 */ 625 if (uio->uio_segflg == UIO_USERSPACE) { 626 procp = ttoproc(curthread); 627 as = procp->p_as; 628 } else { 629 procp = NULL; 630 as = &kas; 631 } 632 *statusp = DIRECTIO_SUCCESS; 633 error = 0; 634 newerror = 0; 635 resid = uio->uio_resid; 636 bytes_written = 0; 637 ufs_directio_kstats.logical_writes.value.ui64++; 638 while (error == 0 && newerror == 0 && resid && uio->uio_iovcnt) { 639 size_t pglck_len, pglck_size; 640 caddr_t pglck_base; 641 page_t **pplist, **spplist; 642 643 tail = NULL; 644 645 /* 646 * Adjust number of bytes 647 */ 648 iov = uio->uio_iov; 649 pglck_len = (size_t)MIN(iov->iov_len, resid); 650 pglck_base = iov->iov_base; 651 if (pglck_len == 0) { 652 uio->uio_iov++; 653 uio->uio_iovcnt--; 654 continue; 655 } 656 657 /* 658 * Try to Lock down the largest chunck of pages possible. 659 */ 660 pglck_len = (size_t)MIN(pglck_len, ufsvfsp->vfs_ioclustsz); 661 error = as_pagelock(as, &pplist, pglck_base, pglck_len, S_READ); 662 663 if (error) 664 break; 665 666 pglck_size = pglck_len; 667 while (pglck_len) { 668 669 nbytes = pglck_len; 670 uoff = uio->uio_loffset; 671 672 if (!bmap_peek) { 673 674 /* 675 * Re-adjust number of bytes to contiguous 676 * range. May have already called bmap_read 677 * in the case of a concurrent rewrite. 678 */ 679 len = (ssize_t)blkroundup(fs, nbytes); 680 error = bmap_read(ip, uoff, &bn, &len); 681 if (error) 682 break; 683 if (bn == UFS_HOLE || len == 0) 684 break; 685 } 686 nbytes = (size_t)MIN(nbytes, len); 687 bmap_peek = 0; 688 689 /* 690 * Get the pagelist pointer for this offset to be 691 * passed to directio_start. 692 */ 693 694 if (pplist != NULL) 695 spplist = pplist + 696 btop((uintptr_t)iov->iov_base - 697 ((uintptr_t)pglck_base & PAGEMASK)); 698 else 699 spplist = NULL; 700 701 /* 702 * Kick off the direct write requests 703 */ 704 directio_start(ufsvfsp, ip, nbytes, ldbtob(bn), 705 iov->iov_base, S_READ, procp, &tail, spplist); 706 707 /* 708 * Adjust pointers and counters 709 */ 710 iov->iov_len -= nbytes; 711 iov->iov_base += nbytes; 712 uio->uio_loffset += nbytes; 713 resid -= nbytes; 714 pglck_len -= nbytes; 715 } 716 717 /* 718 * Wait for outstanding requests 719 */ 720 newerror = directio_wait(tail, &bytes_written); 721 722 /* 723 * Release VM resources 724 */ 725 as_pageunlock(as, pplist, pglck_base, pglck_size, S_READ); 726 727 } 728 729 if (!exclusive) { 730 atomic_add_32(&ufs_cur_writes, -1); 731 /* 732 * If this write was done shared, readers may 733 * have pulled in unmodified pages. Get rid of 734 * these potentially stale pages. 735 */ 736 if (vn_has_cached_data(vp)) { 737 rw_exit(&ip->i_contents); 738 rw_enter(&ip->i_contents, RW_WRITER); 739 (void) VOP_PUTPAGE(vp, (offset_t)0, (size_t)0, 740 B_INVAL, cr, NULL); 741 ufs_directio_kstats.nflushes.value.ui64++; 742 rw_downgrade(&ip->i_contents); 743 } 744 } 745 746 /* 747 * If error, adjust resid to begin at the first 748 * un-writable byte. 749 */ 750 if (error == 0) 751 error = newerror; 752 if (error) 753 resid = uio->uio_resid - bytes_written; 754 arg_uio->uio_resid = resid; 755 756 if (!rewrite) { 757 ip->i_flag |= IUPD | ICHG; 758 /* Caller will update i_seq */ 759 TRANS_INODE(ip->i_ufsvfs, ip); 760 } 761 /* 762 * If there is a residual; adjust the EOF if necessary 763 */ 764 if (resid) { 765 if (size != ip->i_size) { 766 if (uio->uio_loffset > size) 767 size = uio->uio_loffset; 768 (void) ufs_itrunc(ip, size, 0, cr); 769 } 770 } 771 772 if (uio == ©_uio) 773 kmem_free(copy_base, copy_resid); 774 775 return (error); 776 777 errout: 778 if (uio == ©_uio) 779 kmem_free(copy_base, copy_resid); 780 781 return (0); 782 } 783 /* 784 * Direct read of a hole 785 */ 786 static int 787 directio_hole(struct uio *uio, size_t nbytes) 788 { 789 int error = 0, nzero; 790 uio_t phys_uio; 791 iovec_t phys_iov; 792 793 ufs_directio_kstats.hole_reads.value.ui64++; 794 ufs_directio_kstats.nread.value.ui64 += nbytes; 795 796 phys_iov.iov_base = uio->uio_iov->iov_base; 797 phys_iov.iov_len = nbytes; 798 799 phys_uio.uio_iov = &phys_iov; 800 phys_uio.uio_iovcnt = 1; 801 phys_uio.uio_resid = phys_iov.iov_len; 802 phys_uio.uio_segflg = uio->uio_segflg; 803 phys_uio.uio_extflg = uio->uio_extflg; 804 while (error == 0 && phys_uio.uio_resid) { 805 nzero = (int)MIN(phys_iov.iov_len, ufs_directio_zero_len); 806 error = uiomove(ufs_directio_zero_buf, nzero, UIO_READ, 807 &phys_uio); 808 } 809 return (error); 810 } 811 812 /* 813 * Direct Read 814 */ 815 int 816 ufs_directio_read(struct inode *ip, uio_t *uio, cred_t *cr, int *statusp) 817 { 818 ssize_t resid, bytes_read; 819 u_offset_t size, uoff; 820 int error, newerror, len; 821 size_t nbytes; 822 struct fs *fs; 823 vnode_t *vp; 824 daddr_t bn; 825 iovec_t *iov; 826 struct ufsvfs *ufsvfsp = ip->i_ufsvfs; 827 struct proc *procp; 828 struct as *as; 829 struct directio_buf *tail; 830 831 /* 832 * assume that directio isn't possible (normal case) 833 */ 834 *statusp = DIRECTIO_FAILURE; 835 836 /* 837 * Don't go direct 838 */ 839 if (ufs_directio_enabled == 0) 840 return (0); 841 842 /* 843 * mapped file; nevermind 844 */ 845 if (ip->i_mapcnt) 846 return (0); 847 848 /* 849 * CAN WE DO DIRECT IO? 850 */ 851 /* 852 * must be sector aligned 853 */ 854 uoff = uio->uio_loffset; 855 resid = uio->uio_resid; 856 if ((uoff & (u_offset_t)(DEV_BSIZE - 1)) || (resid & (DEV_BSIZE - 1))) 857 return (0); 858 /* 859 * must be short aligned and sector aligned 860 */ 861 iov = uio->uio_iov; 862 nbytes = uio->uio_iovcnt; 863 while (nbytes--) { 864 if (((size_t)iov->iov_len & (DEV_BSIZE - 1)) != 0) 865 return (0); 866 if ((intptr_t)(iov++->iov_base) & 1) 867 return (0); 868 } 869 870 /* 871 * DIRECTIO 872 */ 873 fs = ip->i_fs; 874 875 /* 876 * don't read past EOF 877 */ 878 size = ip->i_size; 879 880 /* 881 * The file offset is past EOF so bail out here; we don't want 882 * to update uio_resid and make it look like we read something. 883 * We say that direct I/O was a success to avoid having rdip() 884 * go through the same "read past EOF logic". 885 */ 886 if (uoff >= size) { 887 *statusp = DIRECTIO_SUCCESS; 888 return (0); 889 } 890 891 /* 892 * The read would extend past EOF so make it smaller. 893 */ 894 if ((uoff + resid) > size) { 895 resid = size - uoff; 896 /* 897 * recheck sector alignment 898 */ 899 if (resid & (DEV_BSIZE - 1)) 900 return (0); 901 } 902 903 /* 904 * At this point, we know there is some real work to do. 905 */ 906 ASSERT(resid); 907 908 /* 909 * get rid of cached pages 910 */ 911 vp = ITOV(ip); 912 if (vn_has_cached_data(vp)) { 913 rw_exit(&ip->i_contents); 914 rw_enter(&ip->i_contents, RW_WRITER); 915 (void) VOP_PUTPAGE(vp, (offset_t)0, (size_t)0, 916 B_INVAL, cr, NULL); 917 if (vn_has_cached_data(vp)) 918 return (0); 919 rw_downgrade(&ip->i_contents); 920 ufs_directio_kstats.nflushes.value.ui64++; 921 } 922 /* 923 * Direct Reads 924 */ 925 926 /* 927 * proc and as are for VM operations in directio_start() 928 */ 929 if (uio->uio_segflg == UIO_USERSPACE) { 930 procp = ttoproc(curthread); 931 as = procp->p_as; 932 } else { 933 procp = NULL; 934 as = &kas; 935 } 936 937 *statusp = DIRECTIO_SUCCESS; 938 error = 0; 939 newerror = 0; 940 bytes_read = 0; 941 ufs_directio_kstats.logical_reads.value.ui64++; 942 while (error == 0 && newerror == 0 && resid && uio->uio_iovcnt) { 943 size_t pglck_len, pglck_size; 944 caddr_t pglck_base; 945 page_t **pplist, **spplist; 946 947 tail = NULL; 948 949 /* 950 * Adjust number of bytes 951 */ 952 iov = uio->uio_iov; 953 pglck_len = (size_t)MIN(iov->iov_len, resid); 954 pglck_base = iov->iov_base; 955 if (pglck_len == 0) { 956 uio->uio_iov++; 957 uio->uio_iovcnt--; 958 continue; 959 } 960 961 /* 962 * Try to Lock down the largest chunck of pages possible. 963 */ 964 pglck_len = (size_t)MIN(pglck_len, ufsvfsp->vfs_ioclustsz); 965 error = as_pagelock(as, &pplist, pglck_base, 966 pglck_len, S_WRITE); 967 968 if (error) 969 break; 970 971 pglck_size = pglck_len; 972 while (pglck_len) { 973 974 nbytes = pglck_len; 975 uoff = uio->uio_loffset; 976 977 /* 978 * Re-adjust number of bytes to contiguous range 979 */ 980 len = (ssize_t)blkroundup(fs, nbytes); 981 error = bmap_read(ip, uoff, &bn, &len); 982 if (error) 983 break; 984 985 if (bn == UFS_HOLE) { 986 nbytes = (size_t)MIN(fs->fs_bsize - 987 (long)blkoff(fs, uoff), nbytes); 988 error = directio_hole(uio, nbytes); 989 /* 990 * Hole reads are not added to the list 991 * processed by directio_wait() below so 992 * account for bytes read here. 993 */ 994 if (!error) 995 bytes_read += nbytes; 996 } else { 997 nbytes = (size_t)MIN(nbytes, len); 998 999 /* 1000 * Get the pagelist pointer for this offset 1001 * to be passed to directio_start. 1002 */ 1003 if (pplist != NULL) 1004 spplist = pplist + 1005 btop((uintptr_t)iov->iov_base - 1006 ((uintptr_t)pglck_base & PAGEMASK)); 1007 else 1008 spplist = NULL; 1009 1010 /* 1011 * Kick off the direct read requests 1012 */ 1013 directio_start(ufsvfsp, ip, nbytes, 1014 ldbtob(bn), iov->iov_base, 1015 S_WRITE, procp, &tail, spplist); 1016 } 1017 1018 if (error) 1019 break; 1020 1021 /* 1022 * Adjust pointers and counters 1023 */ 1024 iov->iov_len -= nbytes; 1025 iov->iov_base += nbytes; 1026 uio->uio_loffset += nbytes; 1027 resid -= nbytes; 1028 pglck_len -= nbytes; 1029 } 1030 1031 /* 1032 * Wait for outstanding requests 1033 */ 1034 newerror = directio_wait(tail, &bytes_read); 1035 /* 1036 * Release VM resources 1037 */ 1038 as_pageunlock(as, pplist, pglck_base, pglck_size, S_WRITE); 1039 1040 } 1041 1042 /* 1043 * If error, adjust resid to begin at the first 1044 * un-read byte. 1045 */ 1046 if (error == 0) 1047 error = newerror; 1048 uio->uio_resid -= bytes_read; 1049 return (error); 1050 } 1051