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, Version 1.0 only 6 * (the "License"). You may not use this file except in compliance 7 * with the License. 8 * 9 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 10 * or http://www.opensolaris.org/os/licensing. 11 * See the License for the specific language governing permissions 12 * and limitations under the License. 13 * 14 * When distributing Covered Code, include this CDDL HEADER in each 15 * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 16 * If applicable, add the following below this CDDL HEADER, with the 17 * fields enclosed by brackets "[]" replaced with your own identifying 18 * information: Portions Copyright [yyyy] [name of copyright owner] 19 * 20 * CDDL HEADER END 21 */ 22 /* 23 * Copyright 2005 Sun Microsystems, Inc. All rights reserved. 24 * Use is subject to license terms. 25 */ 26 27 /* Copyright (c) 1983, 1984, 1985, 1986, 1987, 1988, 1989 AT&T */ 28 /* All Rights Reserved */ 29 30 /* 31 * Portions of this source code were derived from Berkeley 4.3 BSD 32 * under license from the Regents of the University of California. 33 */ 34 35 #pragma ident "%Z%%M% %I% %E% SMI" 36 37 #include <sys/types.h> 38 #include <sys/t_lock.h> 39 #include <sys/param.h> 40 #include <sys/time.h> 41 #include <sys/systm.h> 42 #include <sys/sysmacros.h> 43 #include <sys/resource.h> 44 #include <sys/signal.h> 45 #include <sys/cred.h> 46 #include <sys/user.h> 47 #include <sys/buf.h> 48 #include <sys/vfs.h> 49 #include <sys/vnode.h> 50 #include <sys/proc.h> 51 #include <sys/disp.h> 52 #include <sys/file.h> 53 #include <sys/fcntl.h> 54 #include <sys/flock.h> 55 #include <sys/kmem.h> 56 #include <sys/uio.h> 57 #include <sys/dnlc.h> 58 #include <sys/conf.h> 59 #include <sys/mman.h> 60 #include <sys/pathname.h> 61 #include <sys/debug.h> 62 #include <sys/vmsystm.h> 63 #include <sys/cmn_err.h> 64 #include <sys/vtrace.h> 65 #include <sys/filio.h> 66 #include <sys/atomic.h> 67 68 #include <sys/fssnap_if.h> 69 #include <sys/fs/ufs_fs.h> 70 #include <sys/fs/ufs_lockfs.h> 71 #include <sys/fs/ufs_filio.h> 72 #include <sys/fs/ufs_inode.h> 73 #include <sys/fs/ufs_fsdir.h> 74 #include <sys/fs/ufs_quota.h> 75 #include <sys/fs/ufs_trans.h> 76 #include <sys/fs/ufs_panic.h> 77 #include <sys/dirent.h> /* must be AFTER <sys/fs/fsdir.h>! */ 78 #include <sys/errno.h> 79 80 #include <sys/filio.h> /* _FIOIO */ 81 82 #include <vm/hat.h> 83 #include <vm/page.h> 84 #include <vm/pvn.h> 85 #include <vm/as.h> 86 #include <vm/seg.h> 87 #include <vm/seg_map.h> 88 #include <vm/seg_vn.h> 89 #include <vm/seg_kmem.h> 90 #include <vm/rm.h> 91 #include <sys/swap.h> 92 #include <sys/epm.h> 93 94 #include <fs/fs_subr.h> 95 96 static void *ufs_directio_zero_buf; 97 static int ufs_directio_zero_len = 8192; 98 99 int ufs_directio_enabled = 1; /* feature is enabled */ 100 101 /* 102 * for kstats reader 103 */ 104 struct ufs_directio_kstats { 105 uint_t logical_reads; 106 uint_t phys_reads; 107 uint_t hole_reads; 108 uint_t nread; 109 uint_t logical_writes; 110 uint_t phys_writes; 111 uint_t nwritten; 112 uint_t nflushes; 113 } ufs_directio_kstats; 114 115 kstat_t *ufs_directio_kstatsp; 116 117 /* 118 * use kmem_cache_create for direct-physio buffers. This has shown 119 * a better cache distribution compared to buffers on the 120 * stack. It also avoids semaphore construction/deconstruction 121 * per request 122 */ 123 struct directio_buf { 124 struct directio_buf *next; 125 char *addr; 126 size_t nbytes; 127 struct buf buf; 128 }; 129 static struct kmem_cache *directio_buf_cache; 130 131 132 /* ARGSUSED */ 133 static int 134 directio_buf_constructor(void *dbp, void *cdrarg, int kmflags) 135 { 136 bioinit((struct buf *)&((struct directio_buf *)dbp)->buf); 137 return (0); 138 } 139 140 /* ARGSUSED */ 141 static void 142 directio_buf_destructor(void *dbp, void *cdrarg) 143 { 144 biofini((struct buf *)&((struct directio_buf *)dbp)->buf); 145 } 146 147 void 148 directio_bufs_init(void) 149 { 150 directio_buf_cache = kmem_cache_create("directio_buf_cache", 151 sizeof (struct directio_buf), 0, 152 directio_buf_constructor, directio_buf_destructor, 153 NULL, NULL, NULL, 0); 154 } 155 156 void 157 ufs_directio_init(void) 158 { 159 /* 160 * kstats 161 */ 162 ufs_directio_kstatsp = kstat_create("ufs directio", 0, 163 "UFS DirectIO Stats", "ufs directio", 164 KSTAT_TYPE_RAW, sizeof (ufs_directio_kstats), 165 KSTAT_FLAG_VIRTUAL | KSTAT_FLAG_WRITABLE); 166 if (ufs_directio_kstatsp) { 167 ufs_directio_kstatsp->ks_data = (void *)&ufs_directio_kstats; 168 kstat_install(ufs_directio_kstatsp); 169 } 170 /* 171 * kzero is broken so we have to use a private buf of zeroes 172 */ 173 ufs_directio_zero_buf = kmem_zalloc(ufs_directio_zero_len, KM_SLEEP); 174 directio_bufs_init(); 175 } 176 177 /* 178 * Wait for the first direct IO operation to finish 179 */ 180 static int 181 directio_wait_one(struct directio_buf *dbp, long *bytes_iop) 182 { 183 buf_t *bp; 184 int error; 185 186 /* 187 * Wait for IO to finish 188 */ 189 bp = &dbp->buf; 190 error = biowait(bp); 191 192 /* 193 * bytes_io will be used to figure out a resid 194 * for the caller. The resid is approximated by reporting 195 * the bytes following the first failed IO as the residual. 196 * 197 * I am cautious about using b_resid because I 198 * am not sure how well the disk drivers maintain it. 199 */ 200 if (error) 201 if (bp->b_resid) 202 *bytes_iop = bp->b_bcount - bp->b_resid; 203 else 204 *bytes_iop = 0; 205 else 206 *bytes_iop += bp->b_bcount; 207 /* 208 * Release direct IO resources 209 */ 210 bp->b_flags &= ~(B_BUSY|B_WANTED|B_PHYS|B_SHADOW); 211 kmem_cache_free(directio_buf_cache, dbp); 212 return (error); 213 } 214 215 /* 216 * Wait for all of the direct IO operations to finish 217 */ 218 219 uint32_t ufs_directio_drop_kpri = 0; /* enable kpri hack */ 220 221 static int 222 directio_wait(struct directio_buf *tail, long *bytes_iop) 223 { 224 int error = 0, newerror; 225 struct directio_buf *dbp; 226 uint_t kpri_req_save; 227 228 /* 229 * The linked list of directio buf structures is maintained 230 * in reverse order (tail->last request->penultimate request->...) 231 */ 232 /* 233 * This is the k_pri_req hack. Large numbers of threads 234 * sleeping with kernel priority will cause scheduler thrashing 235 * on an MP machine. This can be seen running Oracle using 236 * directio to ufs files. Sleep at normal priority here to 237 * more closely mimic physio to a device partition. This 238 * workaround is disabled by default as a niced thread could 239 * be starved from running while holding i_rwlock and i_contents. 240 */ 241 if (ufs_directio_drop_kpri) { 242 kpri_req_save = curthread->t_kpri_req; 243 curthread->t_kpri_req = 0; 244 } 245 while ((dbp = tail) != NULL) { 246 tail = dbp->next; 247 newerror = directio_wait_one(dbp, bytes_iop); 248 if (error == 0) 249 error = newerror; 250 } 251 if (ufs_directio_drop_kpri) 252 curthread->t_kpri_req = kpri_req_save; 253 return (error); 254 } 255 /* 256 * Initiate direct IO request 257 */ 258 static void 259 directio_start(struct ufsvfs *ufsvfsp, dev_t dev, size_t nbytes, 260 offset_t offset, char *addr, enum seg_rw rw, struct proc *procp, 261 struct directio_buf **tailp, page_t **pplist) 262 { 263 buf_t *bp; 264 struct directio_buf *dbp; 265 266 /* 267 * Allocate a directio buf header 268 * Note - list is maintained in reverse order. 269 * directio_wait_one() depends on this fact when 270 * adjusting the ``bytes_io'' param. bytes_io 271 * is used to compute a residual in the case of error. 272 */ 273 dbp = kmem_cache_alloc(directio_buf_cache, KM_SLEEP); 274 dbp->next = *tailp; 275 *tailp = dbp; 276 277 /* 278 * Initialize buf header 279 */ 280 dbp->addr = addr; 281 dbp->nbytes = nbytes; 282 bp = &dbp->buf; 283 bp->b_edev = dev; 284 bp->b_lblkno = btodt(offset); 285 bp->b_bcount = nbytes; 286 bp->b_un.b_addr = addr; 287 bp->b_proc = procp; 288 289 /* 290 * Note that S_WRITE implies B_READ and vice versa: a read(2) 291 * will B_READ data from the filesystem and S_WRITE it into 292 * the user's buffer; a write(2) will S_READ data from the 293 * user's buffer and B_WRITE it to the filesystem. 294 */ 295 if (rw == S_WRITE) { 296 bp->b_flags = B_BUSY | B_PHYS | B_READ; 297 ufs_directio_kstats.phys_reads++; 298 ufs_directio_kstats.nread += nbytes; 299 } else { 300 bp->b_flags = B_BUSY | B_PHYS | B_WRITE; 301 ufs_directio_kstats.phys_writes++; 302 ufs_directio_kstats.nwritten += nbytes; 303 } 304 bp->b_shadow = pplist; 305 if (pplist != NULL) 306 bp->b_flags |= B_SHADOW; 307 308 /* 309 * Issue I/O request. 310 */ 311 ufsvfsp->vfs_iotstamp = lbolt; 312 if (ufsvfsp->vfs_snapshot) 313 fssnap_strategy(&ufsvfsp->vfs_snapshot, bp); 314 else 315 (void) bdev_strategy(bp); 316 317 if (rw == S_WRITE) 318 lwp_stat_update(LWP_STAT_OUBLK, 1); 319 else 320 lwp_stat_update(LWP_STAT_INBLK, 1); 321 322 } 323 324 uint32_t ufs_shared_writes; /* writes done w/ lock shared */ 325 uint32_t ufs_cur_writes; /* # concurrent writes */ 326 uint32_t ufs_maxcur_writes; /* high water concurrent writes */ 327 uint32_t ufs_posix_hits; /* writes done /w lock excl. */ 328 329 /* 330 * Force POSIX syncronous data integrity on all writes for testing. 331 */ 332 uint32_t ufs_force_posix_sdi = 0; 333 334 /* 335 * Direct Write 336 */ 337 338 int 339 ufs_directio_write(struct inode *ip, uio_t *arg_uio, int ioflag, int rewrite, 340 cred_t *cr, int *statusp) 341 { 342 long resid, bytes_written; 343 u_offset_t size, uoff; 344 uio_t *uio = arg_uio; 345 rlim64_t limit = uio->uio_llimit; 346 int on, n, error, newerror, len, has_holes; 347 daddr_t bn; 348 size_t nbytes; 349 struct fs *fs; 350 vnode_t *vp; 351 iovec_t *iov; 352 struct ufsvfs *ufsvfsp = ip->i_ufsvfs; 353 struct proc *procp; 354 struct as *as; 355 struct directio_buf *tail; 356 int exclusive, ncur, bmap_peek; 357 uio_t copy_uio; 358 iovec_t copy_iov; 359 char *copy_base; 360 long copy_resid; 361 362 /* 363 * assume that directio isn't possible (normal case) 364 */ 365 *statusp = DIRECTIO_FAILURE; 366 367 /* 368 * Don't go direct 369 */ 370 if (ufs_directio_enabled == 0) 371 return (0); 372 373 /* 374 * mapped file; nevermind 375 */ 376 if (ip->i_mapcnt) 377 return (0); 378 379 /* 380 * CAN WE DO DIRECT IO? 381 */ 382 uoff = uio->uio_loffset; 383 resid = uio->uio_resid; 384 385 /* 386 * beyond limit 387 */ 388 if (uoff + resid > limit) 389 return (0); 390 391 /* 392 * must be sector aligned 393 */ 394 if ((uoff & (u_offset_t)(DEV_BSIZE - 1)) || (resid & (DEV_BSIZE - 1))) 395 return (0); 396 397 /* 398 * SHOULD WE DO DIRECT IO? 399 */ 400 size = ip->i_size; 401 has_holes = -1; 402 403 /* 404 * only on regular files; no metadata 405 */ 406 if (((ip->i_mode & IFMT) != IFREG) || ip->i_ufsvfs->vfs_qinod == ip) 407 return (0); 408 409 /* 410 * Synchronous, allocating writes run very slow in Direct-Mode 411 * XXX - can be fixed with bmap_write changes for large writes!!! 412 * XXX - can be fixed for updates to "almost-full" files 413 * XXX - WARNING - system hangs if bmap_write() has to 414 * allocate lots of pages since pageout 415 * suspends on locked inode 416 */ 417 if (!rewrite && (ip->i_flag & ISYNC)) { 418 if ((uoff + resid) > size) 419 return (0); 420 has_holes = bmap_has_holes(ip); 421 if (has_holes) 422 return (0); 423 } 424 425 /* 426 * Each iovec must be short aligned and sector aligned. If 427 * one is not, then kmem_alloc a new buffer and copy all of 428 * the smaller buffers into the new buffer. This new 429 * buffer will be short aligned and sector aligned. 430 */ 431 iov = uio->uio_iov; 432 nbytes = uio->uio_iovcnt; 433 while (nbytes--) { 434 if (((uint_t)iov->iov_len & (DEV_BSIZE - 1)) != 0 || 435 (intptr_t)(iov->iov_base) & 1) { 436 copy_resid = uio->uio_resid; 437 copy_base = kmem_alloc(copy_resid, KM_NOSLEEP); 438 if (copy_base == NULL) 439 return (0); 440 copy_iov.iov_base = copy_base; 441 copy_iov.iov_len = copy_resid; 442 copy_uio.uio_iov = ©_iov; 443 copy_uio.uio_iovcnt = 1; 444 copy_uio.uio_segflg = UIO_SYSSPACE; 445 copy_uio.uio_extflg = UIO_COPY_DEFAULT; 446 copy_uio.uio_loffset = uio->uio_loffset; 447 copy_uio.uio_resid = uio->uio_resid; 448 copy_uio.uio_llimit = uio->uio_llimit; 449 error = uiomove(copy_base, copy_resid, UIO_WRITE, uio); 450 if (error) { 451 kmem_free(copy_base, copy_resid); 452 return (0); 453 } 454 uio = ©_uio; 455 break; 456 } 457 iov++; 458 } 459 460 /* 461 * From here on down, all error exits must go to errout and 462 * not simply return a 0. 463 */ 464 465 /* 466 * DIRECTIO 467 */ 468 469 fs = ip->i_fs; 470 471 /* 472 * POSIX check. If attempting a concurrent re-write, make sure 473 * that this will be a single request to the driver to meet 474 * POSIX synchronous data integrity requirements. 475 */ 476 bmap_peek = 0; 477 if (rewrite && ((ioflag & FDSYNC) || ufs_force_posix_sdi)) { 478 int upgrade = 0; 479 480 /* check easy conditions first */ 481 if (uio->uio_iovcnt != 1 || resid > ufsvfsp->vfs_ioclustsz) { 482 upgrade = 1; 483 } else { 484 /* now look for contiguous allocation */ 485 len = (ssize_t)blkroundup(fs, resid); 486 error = bmap_read(ip, uoff, &bn, &len); 487 if (error || bn == UFS_HOLE || len == 0) 488 goto errout; 489 /* save a call to bmap_read later */ 490 bmap_peek = 1; 491 if (len < resid) 492 upgrade = 1; 493 } 494 if (upgrade) { 495 rw_exit(&ip->i_contents); 496 rw_enter(&ip->i_contents, RW_WRITER); 497 ufs_posix_hits++; 498 } 499 } 500 501 502 /* 503 * allocate space 504 */ 505 506 /* 507 * If attempting a re-write, there is no allocation to do. 508 * bmap_write would trip an ASSERT if i_contents is held shared. 509 */ 510 if (rewrite) 511 goto skip_alloc; 512 513 do { 514 on = (int)blkoff(fs, uoff); 515 n = (int)MIN(fs->fs_bsize - on, resid); 516 if ((uoff + n) > ip->i_size) { 517 error = bmap_write(ip, uoff, (int)(on + n), 518 (int)(uoff & (offset_t)MAXBOFFSET) == 0, 519 cr); 520 /* Caller is responsible for updating i_seq if needed */ 521 if (error) 522 break; 523 ip->i_size = uoff + n; 524 ip->i_flag |= IATTCHG; 525 } else if (n == MAXBSIZE) { 526 error = bmap_write(ip, uoff, (int)(on + n), 1, cr); 527 /* Caller is responsible for updating i_seq if needed */ 528 } else { 529 if (has_holes < 0) 530 has_holes = bmap_has_holes(ip); 531 if (has_holes) { 532 uint_t blk_size; 533 u_offset_t offset; 534 535 offset = uoff & (offset_t)fs->fs_bmask; 536 blk_size = (int)blksize(fs, ip, 537 (daddr_t)lblkno(fs, offset)); 538 error = bmap_write(ip, uoff, blk_size, 0, cr); 539 /* 540 * Caller is responsible for updating 541 * i_seq if needed 542 */ 543 } else 544 error = 0; 545 } 546 if (error) 547 break; 548 uoff += n; 549 resid -= n; 550 /* 551 * if file has grown larger than 2GB, set flag 552 * in superblock if not already set 553 */ 554 if ((ip->i_size > MAXOFF32_T) && 555 !(fs->fs_flags & FSLARGEFILES)) { 556 ASSERT(ufsvfsp->vfs_lfflags & UFS_LARGEFILES); 557 mutex_enter(&ufsvfsp->vfs_lock); 558 fs->fs_flags |= FSLARGEFILES; 559 ufs_sbwrite(ufsvfsp); 560 mutex_exit(&ufsvfsp->vfs_lock); 561 } 562 } while (resid); 563 564 if (error) { 565 /* 566 * restore original state 567 */ 568 if (resid) { 569 if (size == ip->i_size) 570 goto errout; 571 (void) ufs_itrunc(ip, size, 0, cr); 572 } 573 /* 574 * try non-directio path 575 */ 576 goto errout; 577 } 578 skip_alloc: 579 580 /* 581 * get rid of cached pages 582 */ 583 vp = ITOV(ip); 584 exclusive = rw_write_held(&ip->i_contents); 585 if (vn_has_cached_data(vp)) { 586 if (!exclusive) { 587 /* 588 * Still holding i_rwlock, so no allocations 589 * can happen after dropping contents. 590 */ 591 rw_exit(&ip->i_contents); 592 rw_enter(&ip->i_contents, RW_WRITER); 593 } 594 (void) VOP_PUTPAGE(vp, (offset_t)0, (size_t)0, B_INVAL, cr); 595 if (vn_has_cached_data(vp)) 596 goto errout; 597 if (!exclusive) 598 rw_downgrade(&ip->i_contents); 599 ufs_directio_kstats.nflushes++; 600 } 601 602 /* 603 * Direct Writes 604 */ 605 606 if (!exclusive) { 607 ufs_shared_writes++; 608 ncur = atomic_add_32_nv(&ufs_cur_writes, 1); 609 if (ncur > ufs_maxcur_writes) 610 ufs_maxcur_writes = ncur; 611 } 612 613 /* 614 * proc and as are for VM operations in directio_start() 615 */ 616 if (uio->uio_segflg == UIO_USERSPACE) { 617 procp = ttoproc(curthread); 618 as = procp->p_as; 619 } else { 620 procp = NULL; 621 as = &kas; 622 } 623 *statusp = DIRECTIO_SUCCESS; 624 error = 0; 625 newerror = 0; 626 resid = uio->uio_resid; 627 bytes_written = 0; 628 ufs_directio_kstats.logical_writes++; 629 while (error == 0 && newerror == 0 && resid && uio->uio_iovcnt) { 630 size_t pglck_len, pglck_size; 631 caddr_t pglck_base; 632 page_t **pplist, **spplist; 633 634 tail = NULL; 635 636 /* 637 * Adjust number of bytes 638 */ 639 iov = uio->uio_iov; 640 pglck_len = (size_t)MIN(iov->iov_len, resid); 641 pglck_base = iov->iov_base; 642 if (pglck_len == 0) { 643 uio->uio_iov++; 644 uio->uio_iovcnt--; 645 continue; 646 } 647 648 /* 649 * Try to Lock down the largest chunck of pages possible. 650 */ 651 pglck_len = (size_t)MIN(pglck_len, ufsvfsp->vfs_ioclustsz); 652 error = as_pagelock(as, &pplist, pglck_base, pglck_len, S_READ); 653 654 if (error) 655 break; 656 657 pglck_size = pglck_len; 658 while (pglck_len) { 659 660 nbytes = pglck_len; 661 uoff = uio->uio_loffset; 662 663 if (!bmap_peek) { 664 665 /* 666 * Re-adjust number of bytes to contiguous 667 * range. May have already called bmap_read 668 * in the case of a concurrent rewrite. 669 */ 670 len = (ssize_t)blkroundup(fs, nbytes); 671 error = bmap_read(ip, uoff, &bn, &len); 672 if (error) 673 break; 674 if (bn == UFS_HOLE || len == 0) 675 break; 676 } 677 nbytes = (size_t)MIN(nbytes, len); 678 bmap_peek = 0; 679 680 /* 681 * Get the pagelist pointer for this offset to be 682 * passed to directio_start. 683 */ 684 685 if (pplist != NULL) 686 spplist = pplist + 687 btop((uintptr_t)iov->iov_base - 688 ((uintptr_t)pglck_base & PAGEMASK)); 689 else 690 spplist = NULL; 691 692 /* 693 * Kick off the direct write requests 694 */ 695 directio_start(ufsvfsp, ip->i_dev, nbytes, ldbtob(bn), 696 iov->iov_base, S_READ, procp, &tail, spplist); 697 698 /* 699 * Adjust pointers and counters 700 */ 701 iov->iov_len -= nbytes; 702 iov->iov_base += nbytes; 703 uio->uio_loffset += nbytes; 704 resid -= nbytes; 705 pglck_len -= nbytes; 706 } 707 708 /* 709 * Wait for outstanding requests 710 */ 711 newerror = directio_wait(tail, &bytes_written); 712 713 /* 714 * Release VM resources 715 */ 716 as_pageunlock(as, pplist, pglck_base, pglck_size, S_READ); 717 718 } 719 720 if (!exclusive) { 721 atomic_add_32(&ufs_cur_writes, -1); 722 /* 723 * If this write was done shared, readers may 724 * have pulled in unmodified pages. Get rid of 725 * these potentially stale pages. 726 */ 727 if (vn_has_cached_data(vp)) { 728 rw_exit(&ip->i_contents); 729 rw_enter(&ip->i_contents, RW_WRITER); 730 (void) VOP_PUTPAGE(vp, (offset_t)0, (size_t)0, 731 B_INVAL, cr); 732 ufs_directio_kstats.nflushes++; 733 rw_downgrade(&ip->i_contents); 734 } 735 } 736 737 /* 738 * If error, adjust resid to begin at the first 739 * un-writable byte. 740 */ 741 if (error == 0) 742 error = newerror; 743 if (error) 744 resid = uio->uio_resid - bytes_written; 745 arg_uio->uio_resid = resid; 746 747 if (!rewrite) { 748 ip->i_flag |= IUPD | ICHG; 749 /* Caller will update i_seq */ 750 TRANS_INODE(ip->i_ufsvfs, ip); 751 } 752 /* 753 * If there is a residual; adjust the EOF if necessary 754 */ 755 if (resid) { 756 if (size != ip->i_size) { 757 if (uio->uio_loffset > size) 758 size = uio->uio_loffset; 759 (void) ufs_itrunc(ip, size, 0, cr); 760 } 761 } 762 763 if (uio == ©_uio) 764 kmem_free(copy_base, copy_resid); 765 766 return (error); 767 768 errout: 769 if (uio == ©_uio) 770 kmem_free(copy_base, copy_resid); 771 772 return (0); 773 } 774 /* 775 * Direct read of a hole 776 */ 777 static int 778 directio_hole(struct uio *uio, size_t nbytes) 779 { 780 int error = 0, nzero; 781 uio_t phys_uio; 782 iovec_t phys_iov; 783 784 ufs_directio_kstats.hole_reads++; 785 ufs_directio_kstats.nread += nbytes; 786 787 phys_iov.iov_base = uio->uio_iov->iov_base; 788 phys_iov.iov_len = nbytes; 789 790 phys_uio.uio_iov = &phys_iov; 791 phys_uio.uio_iovcnt = 1; 792 phys_uio.uio_resid = phys_iov.iov_len; 793 phys_uio.uio_segflg = uio->uio_segflg; 794 phys_uio.uio_extflg = uio->uio_extflg; 795 while (error == 0 && phys_uio.uio_resid) { 796 nzero = (int)MIN(phys_iov.iov_len, ufs_directio_zero_len); 797 error = uiomove(ufs_directio_zero_buf, nzero, UIO_READ, 798 &phys_uio); 799 } 800 return (error); 801 } 802 803 /* 804 * Direct Read 805 */ 806 int 807 ufs_directio_read(struct inode *ip, uio_t *uio, cred_t *cr, int *statusp) 808 { 809 ssize_t resid, bytes_read; 810 u_offset_t size, uoff; 811 int error, newerror, len; 812 size_t nbytes; 813 struct fs *fs; 814 vnode_t *vp; 815 daddr_t bn; 816 iovec_t *iov; 817 struct ufsvfs *ufsvfsp = ip->i_ufsvfs; 818 struct proc *procp; 819 struct as *as; 820 struct directio_buf *tail; 821 822 /* 823 * assume that directio isn't possible (normal case) 824 */ 825 *statusp = DIRECTIO_FAILURE; 826 827 /* 828 * Don't go direct 829 */ 830 if (ufs_directio_enabled == 0) 831 return (0); 832 833 /* 834 * mapped file; nevermind 835 */ 836 if (ip->i_mapcnt) 837 return (0); 838 839 /* 840 * CAN WE DO DIRECT IO? 841 */ 842 /* 843 * must be sector aligned 844 */ 845 uoff = uio->uio_loffset; 846 resid = uio->uio_resid; 847 if ((uoff & (u_offset_t)(DEV_BSIZE - 1)) || (resid & (DEV_BSIZE - 1))) 848 return (0); 849 /* 850 * must be short aligned and sector aligned 851 */ 852 iov = uio->uio_iov; 853 nbytes = uio->uio_iovcnt; 854 while (nbytes--) { 855 if (((size_t)iov->iov_len & (DEV_BSIZE - 1)) != 0) 856 return (0); 857 if ((intptr_t)(iov++->iov_base) & 1) 858 return (0); 859 } 860 861 /* 862 * DIRECTIO 863 */ 864 fs = ip->i_fs; 865 866 /* 867 * don't read past EOF 868 */ 869 size = ip->i_size; 870 871 /* 872 * The file offset is past EOF so bail out here; we don't want 873 * to update uio_resid and make it look like we read something. 874 * We say that direct I/O was a success to avoid having rdip() 875 * go through the same "read past EOF logic". 876 */ 877 if (uoff >= size) { 878 *statusp = DIRECTIO_SUCCESS; 879 return (0); 880 } 881 882 /* 883 * The read would extend past EOF so make it smaller. 884 */ 885 if ((uoff + resid) > size) { 886 resid = size - uoff; 887 /* 888 * recheck sector alignment 889 */ 890 if (resid & (DEV_BSIZE - 1)) 891 return (0); 892 } 893 894 /* 895 * At this point, we know there is some real work to do. 896 */ 897 ASSERT(resid); 898 899 /* 900 * get rid of cached pages 901 */ 902 vp = ITOV(ip); 903 if (vn_has_cached_data(vp)) { 904 rw_exit(&ip->i_contents); 905 rw_enter(&ip->i_contents, RW_WRITER); 906 (void) VOP_PUTPAGE(vp, (offset_t)0, (size_t)0, B_INVAL, cr); 907 if (vn_has_cached_data(vp)) 908 return (0); 909 rw_downgrade(&ip->i_contents); 910 ufs_directio_kstats.nflushes++; 911 } 912 /* 913 * Direct Reads 914 */ 915 916 /* 917 * proc and as are for VM operations in directio_start() 918 */ 919 if (uio->uio_segflg == UIO_USERSPACE) { 920 procp = ttoproc(curthread); 921 as = procp->p_as; 922 } else { 923 procp = NULL; 924 as = &kas; 925 } 926 927 *statusp = DIRECTIO_SUCCESS; 928 error = 0; 929 newerror = 0; 930 bytes_read = 0; 931 ufs_directio_kstats.logical_reads++; 932 while (error == 0 && newerror == 0 && resid && uio->uio_iovcnt) { 933 size_t pglck_len, pglck_size; 934 caddr_t pglck_base; 935 page_t **pplist, **spplist; 936 937 tail = NULL; 938 939 /* 940 * Adjust number of bytes 941 */ 942 iov = uio->uio_iov; 943 pglck_len = (size_t)MIN(iov->iov_len, resid); 944 pglck_base = iov->iov_base; 945 if (pglck_len == 0) { 946 uio->uio_iov++; 947 uio->uio_iovcnt--; 948 continue; 949 } 950 951 /* 952 * Try to Lock down the largest chunck of pages possible. 953 */ 954 pglck_len = (size_t)MIN(pglck_len, ufsvfsp->vfs_ioclustsz); 955 error = as_pagelock(as, &pplist, pglck_base, 956 pglck_len, S_WRITE); 957 958 if (error) 959 break; 960 961 pglck_size = pglck_len; 962 while (pglck_len) { 963 964 nbytes = pglck_len; 965 uoff = uio->uio_loffset; 966 967 /* 968 * Re-adjust number of bytes to contiguous range 969 */ 970 len = (ssize_t)blkroundup(fs, nbytes); 971 error = bmap_read(ip, uoff, &bn, &len); 972 if (error) 973 break; 974 975 if (bn == UFS_HOLE) { 976 nbytes = (size_t)MIN(fs->fs_bsize - 977 (long)blkoff(fs, uoff), nbytes); 978 error = directio_hole(uio, nbytes); 979 /* 980 * Hole reads are not added to the list 981 * processed by directio_wait() below so 982 * account for bytes read here. 983 */ 984 if (!error) 985 bytes_read += nbytes; 986 } else { 987 nbytes = (size_t)MIN(nbytes, len); 988 989 /* 990 * Get the pagelist pointer for this offset 991 * to be passed to directio_start. 992 */ 993 if (pplist != NULL) 994 spplist = pplist + 995 btop((uintptr_t)iov->iov_base - 996 ((uintptr_t)pglck_base & PAGEMASK)); 997 else 998 spplist = NULL; 999 1000 /* 1001 * Kick off the direct read requests 1002 */ 1003 directio_start(ufsvfsp, ip->i_dev, nbytes, 1004 ldbtob(bn), iov->iov_base, 1005 S_WRITE, procp, &tail, spplist); 1006 } 1007 1008 if (error) 1009 break; 1010 1011 /* 1012 * Adjust pointers and counters 1013 */ 1014 iov->iov_len -= nbytes; 1015 iov->iov_base += nbytes; 1016 uio->uio_loffset += nbytes; 1017 resid -= nbytes; 1018 pglck_len -= nbytes; 1019 } 1020 1021 /* 1022 * Wait for outstanding requests 1023 */ 1024 newerror = directio_wait(tail, &bytes_read); 1025 /* 1026 * Release VM resources 1027 */ 1028 as_pageunlock(as, pplist, pglck_base, pglck_size, S_WRITE); 1029 1030 } 1031 1032 /* 1033 * If error, adjust resid to begin at the first 1034 * un-read byte. 1035 */ 1036 if (error == 0) 1037 error = newerror; 1038 uio->uio_resid -= bytes_read; 1039 return (error); 1040 } 1041