vfs_vnops.c revision 253106
1/*- 2 * Copyright (c) 1982, 1986, 1989, 1993 3 * The Regents of the University of California. All rights reserved. 4 * (c) UNIX System Laboratories, Inc. 5 * All or some portions of this file are derived from material licensed 6 * to the University of California by American Telephone and Telegraph 7 * Co. or Unix System Laboratories, Inc. and are reproduced herein with 8 * the permission of UNIX System Laboratories, Inc. 9 * 10 * Copyright (c) 2012 Konstantin Belousov <kib@FreeBSD.org> 11 * Copyright (c) 2013 The FreeBSD Foundation 12 * 13 * Portions of this software were developed by Konstantin Belousov 14 * under sponsorship from the FreeBSD Foundation. 15 * 16 * Redistribution and use in source and binary forms, with or without 17 * modification, are permitted provided that the following conditions 18 * are met: 19 * 1. Redistributions of source code must retain the above copyright 20 * notice, this list of conditions and the following disclaimer. 21 * 2. Redistributions in binary form must reproduce the above copyright 22 * notice, this list of conditions and the following disclaimer in the 23 * documentation and/or other materials provided with the distribution. 24 * 4. Neither the name of the University nor the names of its contributors 25 * may be used to endorse or promote products derived from this software 26 * without specific prior written permission. 27 * 28 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 29 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 30 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 31 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 32 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 33 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 34 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 35 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 36 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 37 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 38 * SUCH DAMAGE. 39 * 40 * @(#)vfs_vnops.c 8.2 (Berkeley) 1/21/94 41 */ 42 43#include <sys/cdefs.h> 44__FBSDID("$FreeBSD: head/sys/kern/vfs_vnops.c 253106 2013-07-09 20:49:32Z kib $"); 45 46#include <sys/param.h> 47#include <sys/systm.h> 48#include <sys/fcntl.h> 49#include <sys/file.h> 50#include <sys/kdb.h> 51#include <sys/stat.h> 52#include <sys/priv.h> 53#include <sys/proc.h> 54#include <sys/limits.h> 55#include <sys/lock.h> 56#include <sys/mount.h> 57#include <sys/mutex.h> 58#include <sys/namei.h> 59#include <sys/vnode.h> 60#include <sys/bio.h> 61#include <sys/buf.h> 62#include <sys/filio.h> 63#include <sys/resourcevar.h> 64#include <sys/rwlock.h> 65#include <sys/sx.h> 66#include <sys/sysctl.h> 67#include <sys/ttycom.h> 68#include <sys/conf.h> 69#include <sys/syslog.h> 70#include <sys/unistd.h> 71 72#include <security/audit/audit.h> 73#include <security/mac/mac_framework.h> 74 75#include <vm/vm.h> 76#include <vm/vm_extern.h> 77#include <vm/pmap.h> 78#include <vm/vm_map.h> 79#include <vm/vm_object.h> 80#include <vm/vm_page.h> 81 82static fo_rdwr_t vn_read; 83static fo_rdwr_t vn_write; 84static fo_rdwr_t vn_io_fault; 85static fo_truncate_t vn_truncate; 86static fo_ioctl_t vn_ioctl; 87static fo_poll_t vn_poll; 88static fo_kqfilter_t vn_kqfilter; 89static fo_stat_t vn_statfile; 90static fo_close_t vn_closefile; 91 92struct fileops vnops = { 93 .fo_read = vn_io_fault, 94 .fo_write = vn_io_fault, 95 .fo_truncate = vn_truncate, 96 .fo_ioctl = vn_ioctl, 97 .fo_poll = vn_poll, 98 .fo_kqfilter = vn_kqfilter, 99 .fo_stat = vn_statfile, 100 .fo_close = vn_closefile, 101 .fo_chmod = vn_chmod, 102 .fo_chown = vn_chown, 103 .fo_flags = DFLAG_PASSABLE | DFLAG_SEEKABLE 104}; 105 106int 107vn_open(ndp, flagp, cmode, fp) 108 struct nameidata *ndp; 109 int *flagp, cmode; 110 struct file *fp; 111{ 112 struct thread *td = ndp->ni_cnd.cn_thread; 113 114 return (vn_open_cred(ndp, flagp, cmode, 0, td->td_ucred, fp)); 115} 116 117/* 118 * Common code for vnode open operations via a name lookup. 119 * Lookup the vnode and invoke VOP_CREATE if needed. 120 * Check permissions, and call the VOP_OPEN or VOP_CREATE routine. 121 * 122 * Note that this does NOT free nameidata for the successful case, 123 * due to the NDINIT being done elsewhere. 124 */ 125int 126vn_open_cred(struct nameidata *ndp, int *flagp, int cmode, u_int vn_open_flags, 127 struct ucred *cred, struct file *fp) 128{ 129 struct vnode *vp; 130 struct mount *mp; 131 struct thread *td = ndp->ni_cnd.cn_thread; 132 struct vattr vat; 133 struct vattr *vap = &vat; 134 int fmode, error; 135 136restart: 137 fmode = *flagp; 138 if (fmode & O_CREAT) { 139 ndp->ni_cnd.cn_nameiop = CREATE; 140 ndp->ni_cnd.cn_flags = ISOPEN | LOCKPARENT | LOCKLEAF; 141 if ((fmode & O_EXCL) == 0 && (fmode & O_NOFOLLOW) == 0) 142 ndp->ni_cnd.cn_flags |= FOLLOW; 143 if (!(vn_open_flags & VN_OPEN_NOAUDIT)) 144 ndp->ni_cnd.cn_flags |= AUDITVNODE1; 145 if (vn_open_flags & VN_OPEN_NOCAPCHECK) 146 ndp->ni_cnd.cn_flags |= NOCAPCHECK; 147 bwillwrite(); 148 if ((error = namei(ndp)) != 0) 149 return (error); 150 if (ndp->ni_vp == NULL) { 151 VATTR_NULL(vap); 152 vap->va_type = VREG; 153 vap->va_mode = cmode; 154 if (fmode & O_EXCL) 155 vap->va_vaflags |= VA_EXCLUSIVE; 156 if (vn_start_write(ndp->ni_dvp, &mp, V_NOWAIT) != 0) { 157 NDFREE(ndp, NDF_ONLY_PNBUF); 158 vput(ndp->ni_dvp); 159 if ((error = vn_start_write(NULL, &mp, 160 V_XSLEEP | PCATCH)) != 0) 161 return (error); 162 goto restart; 163 } 164#ifdef MAC 165 error = mac_vnode_check_create(cred, ndp->ni_dvp, 166 &ndp->ni_cnd, vap); 167 if (error == 0) 168#endif 169 error = VOP_CREATE(ndp->ni_dvp, &ndp->ni_vp, 170 &ndp->ni_cnd, vap); 171 vput(ndp->ni_dvp); 172 vn_finished_write(mp); 173 if (error) { 174 NDFREE(ndp, NDF_ONLY_PNBUF); 175 return (error); 176 } 177 fmode &= ~O_TRUNC; 178 vp = ndp->ni_vp; 179 } else { 180 if (ndp->ni_dvp == ndp->ni_vp) 181 vrele(ndp->ni_dvp); 182 else 183 vput(ndp->ni_dvp); 184 ndp->ni_dvp = NULL; 185 vp = ndp->ni_vp; 186 if (fmode & O_EXCL) { 187 error = EEXIST; 188 goto bad; 189 } 190 fmode &= ~O_CREAT; 191 } 192 } else { 193 ndp->ni_cnd.cn_nameiop = LOOKUP; 194 ndp->ni_cnd.cn_flags = ISOPEN | 195 ((fmode & O_NOFOLLOW) ? NOFOLLOW : FOLLOW) | LOCKLEAF; 196 if (!(fmode & FWRITE)) 197 ndp->ni_cnd.cn_flags |= LOCKSHARED; 198 if (!(vn_open_flags & VN_OPEN_NOAUDIT)) 199 ndp->ni_cnd.cn_flags |= AUDITVNODE1; 200 if (vn_open_flags & VN_OPEN_NOCAPCHECK) 201 ndp->ni_cnd.cn_flags |= NOCAPCHECK; 202 if ((error = namei(ndp)) != 0) 203 return (error); 204 vp = ndp->ni_vp; 205 } 206 error = vn_open_vnode(vp, fmode, cred, td, fp); 207 if (error) 208 goto bad; 209 *flagp = fmode; 210 return (0); 211bad: 212 NDFREE(ndp, NDF_ONLY_PNBUF); 213 vput(vp); 214 *flagp = fmode; 215 ndp->ni_vp = NULL; 216 return (error); 217} 218 219/* 220 * Common code for vnode open operations once a vnode is located. 221 * Check permissions, and call the VOP_OPEN routine. 222 */ 223int 224vn_open_vnode(struct vnode *vp, int fmode, struct ucred *cred, 225 struct thread *td, struct file *fp) 226{ 227 struct mount *mp; 228 accmode_t accmode; 229 struct flock lf; 230 int error, have_flock, lock_flags, type; 231 232 if (vp->v_type == VLNK) 233 return (EMLINK); 234 if (vp->v_type == VSOCK) 235 return (EOPNOTSUPP); 236 if (vp->v_type != VDIR && fmode & O_DIRECTORY) 237 return (ENOTDIR); 238 accmode = 0; 239 if (fmode & (FWRITE | O_TRUNC)) { 240 if (vp->v_type == VDIR) 241 return (EISDIR); 242 accmode |= VWRITE; 243 } 244 if (fmode & FREAD) 245 accmode |= VREAD; 246 if (fmode & FEXEC) 247 accmode |= VEXEC; 248 if ((fmode & O_APPEND) && (fmode & FWRITE)) 249 accmode |= VAPPEND; 250#ifdef MAC 251 error = mac_vnode_check_open(cred, vp, accmode); 252 if (error) 253 return (error); 254#endif 255 if ((fmode & O_CREAT) == 0) { 256 if (accmode & VWRITE) { 257 error = vn_writechk(vp); 258 if (error) 259 return (error); 260 } 261 if (accmode) { 262 error = VOP_ACCESS(vp, accmode, cred, td); 263 if (error) 264 return (error); 265 } 266 } 267 if ((error = VOP_OPEN(vp, fmode, cred, td, fp)) != 0) 268 return (error); 269 270 if (fmode & (O_EXLOCK | O_SHLOCK)) { 271 KASSERT(fp != NULL, ("open with flock requires fp")); 272 lock_flags = VOP_ISLOCKED(vp); 273 VOP_UNLOCK(vp, 0); 274 lf.l_whence = SEEK_SET; 275 lf.l_start = 0; 276 lf.l_len = 0; 277 if (fmode & O_EXLOCK) 278 lf.l_type = F_WRLCK; 279 else 280 lf.l_type = F_RDLCK; 281 type = F_FLOCK; 282 if ((fmode & FNONBLOCK) == 0) 283 type |= F_WAIT; 284 error = VOP_ADVLOCK(vp, (caddr_t)fp, F_SETLK, &lf, type); 285 have_flock = (error == 0); 286 vn_lock(vp, lock_flags | LK_RETRY); 287 if (error == 0 && vp->v_iflag & VI_DOOMED) 288 error = ENOENT; 289 /* 290 * Another thread might have used this vnode as an 291 * executable while the vnode lock was dropped. 292 * Ensure the vnode is still able to be opened for 293 * writing after the lock has been obtained. 294 */ 295 if (error == 0 && accmode & VWRITE) 296 error = vn_writechk(vp); 297 if (error) { 298 VOP_UNLOCK(vp, 0); 299 if (have_flock) { 300 lf.l_whence = SEEK_SET; 301 lf.l_start = 0; 302 lf.l_len = 0; 303 lf.l_type = F_UNLCK; 304 (void) VOP_ADVLOCK(vp, fp, F_UNLCK, &lf, 305 F_FLOCK); 306 } 307 vn_start_write(vp, &mp, V_WAIT); 308 vn_lock(vp, lock_flags | LK_RETRY); 309 (void)VOP_CLOSE(vp, fmode, cred, td); 310 vn_finished_write(mp); 311 return (error); 312 } 313 fp->f_flag |= FHASLOCK; 314 } 315 if (fmode & FWRITE) { 316 VOP_ADD_WRITECOUNT(vp, 1); 317 CTR3(KTR_VFS, "%s: vp %p v_writecount increased to %d", 318 __func__, vp, vp->v_writecount); 319 } 320 ASSERT_VOP_LOCKED(vp, "vn_open_vnode"); 321 return (0); 322} 323 324/* 325 * Check for write permissions on the specified vnode. 326 * Prototype text segments cannot be written. 327 */ 328int 329vn_writechk(vp) 330 register struct vnode *vp; 331{ 332 333 ASSERT_VOP_LOCKED(vp, "vn_writechk"); 334 /* 335 * If there's shared text associated with 336 * the vnode, try to free it up once. If 337 * we fail, we can't allow writing. 338 */ 339 if (VOP_IS_TEXT(vp)) 340 return (ETXTBSY); 341 342 return (0); 343} 344 345/* 346 * Vnode close call 347 */ 348int 349vn_close(vp, flags, file_cred, td) 350 register struct vnode *vp; 351 int flags; 352 struct ucred *file_cred; 353 struct thread *td; 354{ 355 struct mount *mp; 356 int error, lock_flags; 357 358 if (!(flags & FWRITE) && vp->v_mount != NULL && 359 vp->v_mount->mnt_kern_flag & MNTK_EXTENDED_SHARED) 360 lock_flags = LK_SHARED; 361 else 362 lock_flags = LK_EXCLUSIVE; 363 364 vn_start_write(vp, &mp, V_WAIT); 365 vn_lock(vp, lock_flags | LK_RETRY); 366 if (flags & FWRITE) { 367 VNASSERT(vp->v_writecount > 0, vp, 368 ("vn_close: negative writecount")); 369 VOP_ADD_WRITECOUNT(vp, -1); 370 CTR3(KTR_VFS, "%s: vp %p v_writecount decreased to %d", 371 __func__, vp, vp->v_writecount); 372 } 373 error = VOP_CLOSE(vp, flags, file_cred, td); 374 vput(vp); 375 vn_finished_write(mp); 376 return (error); 377} 378 379/* 380 * Heuristic to detect sequential operation. 381 */ 382static int 383sequential_heuristic(struct uio *uio, struct file *fp) 384{ 385 386 if (atomic_load_acq_int(&(fp->f_flag)) & FRDAHEAD) 387 return (fp->f_seqcount << IO_SEQSHIFT); 388 389 /* 390 * Offset 0 is handled specially. open() sets f_seqcount to 1 so 391 * that the first I/O is normally considered to be slightly 392 * sequential. Seeking to offset 0 doesn't change sequentiality 393 * unless previous seeks have reduced f_seqcount to 0, in which 394 * case offset 0 is not special. 395 */ 396 if ((uio->uio_offset == 0 && fp->f_seqcount > 0) || 397 uio->uio_offset == fp->f_nextoff) { 398 /* 399 * f_seqcount is in units of fixed-size blocks so that it 400 * depends mainly on the amount of sequential I/O and not 401 * much on the number of sequential I/O's. The fixed size 402 * of 16384 is hard-coded here since it is (not quite) just 403 * a magic size that works well here. This size is more 404 * closely related to the best I/O size for real disks than 405 * to any block size used by software. 406 */ 407 fp->f_seqcount += howmany(uio->uio_resid, 16384); 408 if (fp->f_seqcount > IO_SEQMAX) 409 fp->f_seqcount = IO_SEQMAX; 410 return (fp->f_seqcount << IO_SEQSHIFT); 411 } 412 413 /* Not sequential. Quickly draw-down sequentiality. */ 414 if (fp->f_seqcount > 1) 415 fp->f_seqcount = 1; 416 else 417 fp->f_seqcount = 0; 418 return (0); 419} 420 421/* 422 * Package up an I/O request on a vnode into a uio and do it. 423 */ 424int 425vn_rdwr(enum uio_rw rw, struct vnode *vp, void *base, int len, off_t offset, 426 enum uio_seg segflg, int ioflg, struct ucred *active_cred, 427 struct ucred *file_cred, ssize_t *aresid, struct thread *td) 428{ 429 struct uio auio; 430 struct iovec aiov; 431 struct mount *mp; 432 struct ucred *cred; 433 void *rl_cookie; 434 int error, lock_flags; 435 436 auio.uio_iov = &aiov; 437 auio.uio_iovcnt = 1; 438 aiov.iov_base = base; 439 aiov.iov_len = len; 440 auio.uio_resid = len; 441 auio.uio_offset = offset; 442 auio.uio_segflg = segflg; 443 auio.uio_rw = rw; 444 auio.uio_td = td; 445 error = 0; 446 447 if ((ioflg & IO_NODELOCKED) == 0) { 448 if (rw == UIO_READ) { 449 rl_cookie = vn_rangelock_rlock(vp, offset, 450 offset + len); 451 } else { 452 rl_cookie = vn_rangelock_wlock(vp, offset, 453 offset + len); 454 } 455 mp = NULL; 456 if (rw == UIO_WRITE) { 457 if (vp->v_type != VCHR && 458 (error = vn_start_write(vp, &mp, V_WAIT | PCATCH)) 459 != 0) 460 goto out; 461 if (MNT_SHARED_WRITES(mp) || 462 ((mp == NULL) && MNT_SHARED_WRITES(vp->v_mount))) 463 lock_flags = LK_SHARED; 464 else 465 lock_flags = LK_EXCLUSIVE; 466 } else 467 lock_flags = LK_SHARED; 468 vn_lock(vp, lock_flags | LK_RETRY); 469 } else 470 rl_cookie = NULL; 471 472 ASSERT_VOP_LOCKED(vp, "IO_NODELOCKED with no vp lock held"); 473#ifdef MAC 474 if ((ioflg & IO_NOMACCHECK) == 0) { 475 if (rw == UIO_READ) 476 error = mac_vnode_check_read(active_cred, file_cred, 477 vp); 478 else 479 error = mac_vnode_check_write(active_cred, file_cred, 480 vp); 481 } 482#endif 483 if (error == 0) { 484 if (file_cred != NULL) 485 cred = file_cred; 486 else 487 cred = active_cred; 488 if (rw == UIO_READ) 489 error = VOP_READ(vp, &auio, ioflg, cred); 490 else 491 error = VOP_WRITE(vp, &auio, ioflg, cred); 492 } 493 if (aresid) 494 *aresid = auio.uio_resid; 495 else 496 if (auio.uio_resid && error == 0) 497 error = EIO; 498 if ((ioflg & IO_NODELOCKED) == 0) { 499 VOP_UNLOCK(vp, 0); 500 if (mp != NULL) 501 vn_finished_write(mp); 502 } 503 out: 504 if (rl_cookie != NULL) 505 vn_rangelock_unlock(vp, rl_cookie); 506 return (error); 507} 508 509/* 510 * Package up an I/O request on a vnode into a uio and do it. The I/O 511 * request is split up into smaller chunks and we try to avoid saturating 512 * the buffer cache while potentially holding a vnode locked, so we 513 * check bwillwrite() before calling vn_rdwr(). We also call kern_yield() 514 * to give other processes a chance to lock the vnode (either other processes 515 * core'ing the same binary, or unrelated processes scanning the directory). 516 */ 517int 518vn_rdwr_inchunks(rw, vp, base, len, offset, segflg, ioflg, active_cred, 519 file_cred, aresid, td) 520 enum uio_rw rw; 521 struct vnode *vp; 522 void *base; 523 size_t len; 524 off_t offset; 525 enum uio_seg segflg; 526 int ioflg; 527 struct ucred *active_cred; 528 struct ucred *file_cred; 529 size_t *aresid; 530 struct thread *td; 531{ 532 int error = 0; 533 ssize_t iaresid; 534 535 do { 536 int chunk; 537 538 /* 539 * Force `offset' to a multiple of MAXBSIZE except possibly 540 * for the first chunk, so that filesystems only need to 541 * write full blocks except possibly for the first and last 542 * chunks. 543 */ 544 chunk = MAXBSIZE - (uoff_t)offset % MAXBSIZE; 545 546 if (chunk > len) 547 chunk = len; 548 if (rw != UIO_READ && vp->v_type == VREG) 549 bwillwrite(); 550 iaresid = 0; 551 error = vn_rdwr(rw, vp, base, chunk, offset, segflg, 552 ioflg, active_cred, file_cred, &iaresid, td); 553 len -= chunk; /* aresid calc already includes length */ 554 if (error) 555 break; 556 offset += chunk; 557 base = (char *)base + chunk; 558 kern_yield(PRI_USER); 559 } while (len); 560 if (aresid) 561 *aresid = len + iaresid; 562 return (error); 563} 564 565off_t 566foffset_lock(struct file *fp, int flags) 567{ 568 struct mtx *mtxp; 569 off_t res; 570 571 KASSERT((flags & FOF_OFFSET) == 0, ("FOF_OFFSET passed")); 572 573#if OFF_MAX <= LONG_MAX 574 /* 575 * Caller only wants the current f_offset value. Assume that 576 * the long and shorter integer types reads are atomic. 577 */ 578 if ((flags & FOF_NOLOCK) != 0) 579 return (fp->f_offset); 580#endif 581 582 /* 583 * According to McKusick the vn lock was protecting f_offset here. 584 * It is now protected by the FOFFSET_LOCKED flag. 585 */ 586 mtxp = mtx_pool_find(mtxpool_sleep, fp); 587 mtx_lock(mtxp); 588 if ((flags & FOF_NOLOCK) == 0) { 589 while (fp->f_vnread_flags & FOFFSET_LOCKED) { 590 fp->f_vnread_flags |= FOFFSET_LOCK_WAITING; 591 msleep(&fp->f_vnread_flags, mtxp, PUSER -1, 592 "vofflock", 0); 593 } 594 fp->f_vnread_flags |= FOFFSET_LOCKED; 595 } 596 res = fp->f_offset; 597 mtx_unlock(mtxp); 598 return (res); 599} 600 601void 602foffset_unlock(struct file *fp, off_t val, int flags) 603{ 604 struct mtx *mtxp; 605 606 KASSERT((flags & FOF_OFFSET) == 0, ("FOF_OFFSET passed")); 607 608#if OFF_MAX <= LONG_MAX 609 if ((flags & FOF_NOLOCK) != 0) { 610 if ((flags & FOF_NOUPDATE) == 0) 611 fp->f_offset = val; 612 if ((flags & FOF_NEXTOFF) != 0) 613 fp->f_nextoff = val; 614 return; 615 } 616#endif 617 618 mtxp = mtx_pool_find(mtxpool_sleep, fp); 619 mtx_lock(mtxp); 620 if ((flags & FOF_NOUPDATE) == 0) 621 fp->f_offset = val; 622 if ((flags & FOF_NEXTOFF) != 0) 623 fp->f_nextoff = val; 624 if ((flags & FOF_NOLOCK) == 0) { 625 KASSERT((fp->f_vnread_flags & FOFFSET_LOCKED) != 0, 626 ("Lost FOFFSET_LOCKED")); 627 if (fp->f_vnread_flags & FOFFSET_LOCK_WAITING) 628 wakeup(&fp->f_vnread_flags); 629 fp->f_vnread_flags = 0; 630 } 631 mtx_unlock(mtxp); 632} 633 634void 635foffset_lock_uio(struct file *fp, struct uio *uio, int flags) 636{ 637 638 if ((flags & FOF_OFFSET) == 0) 639 uio->uio_offset = foffset_lock(fp, flags); 640} 641 642void 643foffset_unlock_uio(struct file *fp, struct uio *uio, int flags) 644{ 645 646 if ((flags & FOF_OFFSET) == 0) 647 foffset_unlock(fp, uio->uio_offset, flags); 648} 649 650static int 651get_advice(struct file *fp, struct uio *uio) 652{ 653 struct mtx *mtxp; 654 int ret; 655 656 ret = POSIX_FADV_NORMAL; 657 if (fp->f_advice == NULL) 658 return (ret); 659 660 mtxp = mtx_pool_find(mtxpool_sleep, fp); 661 mtx_lock(mtxp); 662 if (uio->uio_offset >= fp->f_advice->fa_start && 663 uio->uio_offset + uio->uio_resid <= fp->f_advice->fa_end) 664 ret = fp->f_advice->fa_advice; 665 mtx_unlock(mtxp); 666 return (ret); 667} 668 669/* 670 * File table vnode read routine. 671 */ 672static int 673vn_read(fp, uio, active_cred, flags, td) 674 struct file *fp; 675 struct uio *uio; 676 struct ucred *active_cred; 677 int flags; 678 struct thread *td; 679{ 680 struct vnode *vp; 681 struct mtx *mtxp; 682 int error, ioflag; 683 int advice; 684 off_t offset, start, end; 685 686 KASSERT(uio->uio_td == td, ("uio_td %p is not td %p", 687 uio->uio_td, td)); 688 KASSERT(flags & FOF_OFFSET, ("No FOF_OFFSET")); 689 vp = fp->f_vnode; 690 ioflag = 0; 691 if (fp->f_flag & FNONBLOCK) 692 ioflag |= IO_NDELAY; 693 if (fp->f_flag & O_DIRECT) 694 ioflag |= IO_DIRECT; 695 advice = get_advice(fp, uio); 696 vn_lock(vp, LK_SHARED | LK_RETRY); 697 698 switch (advice) { 699 case POSIX_FADV_NORMAL: 700 case POSIX_FADV_SEQUENTIAL: 701 case POSIX_FADV_NOREUSE: 702 ioflag |= sequential_heuristic(uio, fp); 703 break; 704 case POSIX_FADV_RANDOM: 705 /* Disable read-ahead for random I/O. */ 706 break; 707 } 708 offset = uio->uio_offset; 709 710#ifdef MAC 711 error = mac_vnode_check_read(active_cred, fp->f_cred, vp); 712 if (error == 0) 713#endif 714 error = VOP_READ(vp, uio, ioflag, fp->f_cred); 715 fp->f_nextoff = uio->uio_offset; 716 VOP_UNLOCK(vp, 0); 717 if (error == 0 && advice == POSIX_FADV_NOREUSE && 718 offset != uio->uio_offset) { 719 /* 720 * Use POSIX_FADV_DONTNEED to flush clean pages and 721 * buffers for the backing file after a 722 * POSIX_FADV_NOREUSE read(2). To optimize the common 723 * case of using POSIX_FADV_NOREUSE with sequential 724 * access, track the previous implicit DONTNEED 725 * request and grow this request to include the 726 * current read(2) in addition to the previous 727 * DONTNEED. With purely sequential access this will 728 * cause the DONTNEED requests to continously grow to 729 * cover all of the previously read regions of the 730 * file. This allows filesystem blocks that are 731 * accessed by multiple calls to read(2) to be flushed 732 * once the last read(2) finishes. 733 */ 734 start = offset; 735 end = uio->uio_offset - 1; 736 mtxp = mtx_pool_find(mtxpool_sleep, fp); 737 mtx_lock(mtxp); 738 if (fp->f_advice != NULL && 739 fp->f_advice->fa_advice == POSIX_FADV_NOREUSE) { 740 if (start != 0 && fp->f_advice->fa_prevend + 1 == start) 741 start = fp->f_advice->fa_prevstart; 742 else if (fp->f_advice->fa_prevstart != 0 && 743 fp->f_advice->fa_prevstart == end + 1) 744 end = fp->f_advice->fa_prevend; 745 fp->f_advice->fa_prevstart = start; 746 fp->f_advice->fa_prevend = end; 747 } 748 mtx_unlock(mtxp); 749 error = VOP_ADVISE(vp, start, end, POSIX_FADV_DONTNEED); 750 } 751 return (error); 752} 753 754/* 755 * File table vnode write routine. 756 */ 757static int 758vn_write(fp, uio, active_cred, flags, td) 759 struct file *fp; 760 struct uio *uio; 761 struct ucred *active_cred; 762 int flags; 763 struct thread *td; 764{ 765 struct vnode *vp; 766 struct mount *mp; 767 struct mtx *mtxp; 768 int error, ioflag, lock_flags; 769 int advice; 770 off_t offset, start, end; 771 772 KASSERT(uio->uio_td == td, ("uio_td %p is not td %p", 773 uio->uio_td, td)); 774 KASSERT(flags & FOF_OFFSET, ("No FOF_OFFSET")); 775 vp = fp->f_vnode; 776 if (vp->v_type == VREG) 777 bwillwrite(); 778 ioflag = IO_UNIT; 779 if (vp->v_type == VREG && (fp->f_flag & O_APPEND)) 780 ioflag |= IO_APPEND; 781 if (fp->f_flag & FNONBLOCK) 782 ioflag |= IO_NDELAY; 783 if (fp->f_flag & O_DIRECT) 784 ioflag |= IO_DIRECT; 785 if ((fp->f_flag & O_FSYNC) || 786 (vp->v_mount && (vp->v_mount->mnt_flag & MNT_SYNCHRONOUS))) 787 ioflag |= IO_SYNC; 788 mp = NULL; 789 if (vp->v_type != VCHR && 790 (error = vn_start_write(vp, &mp, V_WAIT | PCATCH)) != 0) 791 goto unlock; 792 793 advice = get_advice(fp, uio); 794 795 if (MNT_SHARED_WRITES(mp) || 796 (mp == NULL && MNT_SHARED_WRITES(vp->v_mount))) { 797 lock_flags = LK_SHARED; 798 } else { 799 lock_flags = LK_EXCLUSIVE; 800 } 801 802 vn_lock(vp, lock_flags | LK_RETRY); 803 switch (advice) { 804 case POSIX_FADV_NORMAL: 805 case POSIX_FADV_SEQUENTIAL: 806 case POSIX_FADV_NOREUSE: 807 ioflag |= sequential_heuristic(uio, fp); 808 break; 809 case POSIX_FADV_RANDOM: 810 /* XXX: Is this correct? */ 811 break; 812 } 813 offset = uio->uio_offset; 814 815#ifdef MAC 816 error = mac_vnode_check_write(active_cred, fp->f_cred, vp); 817 if (error == 0) 818#endif 819 error = VOP_WRITE(vp, uio, ioflag, fp->f_cred); 820 fp->f_nextoff = uio->uio_offset; 821 VOP_UNLOCK(vp, 0); 822 if (vp->v_type != VCHR) 823 vn_finished_write(mp); 824 if (error == 0 && advice == POSIX_FADV_NOREUSE && 825 offset != uio->uio_offset) { 826 /* 827 * Use POSIX_FADV_DONTNEED to flush clean pages and 828 * buffers for the backing file after a 829 * POSIX_FADV_NOREUSE write(2). To optimize the 830 * common case of using POSIX_FADV_NOREUSE with 831 * sequential access, track the previous implicit 832 * DONTNEED request and grow this request to include 833 * the current write(2) in addition to the previous 834 * DONTNEED. With purely sequential access this will 835 * cause the DONTNEED requests to continously grow to 836 * cover all of the previously written regions of the 837 * file. 838 * 839 * Note that the blocks just written are almost 840 * certainly still dirty, so this only works when 841 * VOP_ADVISE() calls from subsequent writes push out 842 * the data written by this write(2) once the backing 843 * buffers are clean. However, as compared to forcing 844 * IO_DIRECT, this gives much saner behavior. Write 845 * clustering is still allowed, and clean pages are 846 * merely moved to the cache page queue rather than 847 * outright thrown away. This means a subsequent 848 * read(2) can still avoid hitting the disk if the 849 * pages have not been reclaimed. 850 * 851 * This does make POSIX_FADV_NOREUSE largely useless 852 * with non-sequential access. However, sequential 853 * access is the more common use case and the flag is 854 * merely advisory. 855 */ 856 start = offset; 857 end = uio->uio_offset - 1; 858 mtxp = mtx_pool_find(mtxpool_sleep, fp); 859 mtx_lock(mtxp); 860 if (fp->f_advice != NULL && 861 fp->f_advice->fa_advice == POSIX_FADV_NOREUSE) { 862 if (start != 0 && fp->f_advice->fa_prevend + 1 == start) 863 start = fp->f_advice->fa_prevstart; 864 else if (fp->f_advice->fa_prevstart != 0 && 865 fp->f_advice->fa_prevstart == end + 1) 866 end = fp->f_advice->fa_prevend; 867 fp->f_advice->fa_prevstart = start; 868 fp->f_advice->fa_prevend = end; 869 } 870 mtx_unlock(mtxp); 871 error = VOP_ADVISE(vp, start, end, POSIX_FADV_DONTNEED); 872 } 873 874unlock: 875 return (error); 876} 877 878static const int io_hold_cnt = 16; 879static int vn_io_fault_enable = 1; 880SYSCTL_INT(_debug, OID_AUTO, vn_io_fault_enable, CTLFLAG_RW, 881 &vn_io_fault_enable, 0, "Enable vn_io_fault lock avoidance"); 882static u_long vn_io_faults_cnt; 883SYSCTL_ULONG(_debug, OID_AUTO, vn_io_faults, CTLFLAG_RD, 884 &vn_io_faults_cnt, 0, "Count of vn_io_fault lock avoidance triggers"); 885 886/* 887 * The vn_io_fault() is a wrapper around vn_read() and vn_write() to 888 * prevent the following deadlock: 889 * 890 * Assume that the thread A reads from the vnode vp1 into userspace 891 * buffer buf1 backed by the pages of vnode vp2. If a page in buf1 is 892 * currently not resident, then system ends up with the call chain 893 * vn_read() -> VOP_READ(vp1) -> uiomove() -> [Page Fault] -> 894 * vm_fault(buf1) -> vnode_pager_getpages(vp2) -> VOP_GETPAGES(vp2) 895 * which establishes lock order vp1->vn_lock, then vp2->vn_lock. 896 * If, at the same time, thread B reads from vnode vp2 into buffer buf2 897 * backed by the pages of vnode vp1, and some page in buf2 is not 898 * resident, we get a reversed order vp2->vn_lock, then vp1->vn_lock. 899 * 900 * To prevent the lock order reversal and deadlock, vn_io_fault() does 901 * not allow page faults to happen during VOP_READ() or VOP_WRITE(). 902 * Instead, it first tries to do the whole range i/o with pagefaults 903 * disabled. If all pages in the i/o buffer are resident and mapped, 904 * VOP will succeed (ignoring the genuine filesystem errors). 905 * Otherwise, we get back EFAULT, and vn_io_fault() falls back to do 906 * i/o in chunks, with all pages in the chunk prefaulted and held 907 * using vm_fault_quick_hold_pages(). 908 * 909 * Filesystems using this deadlock avoidance scheme should use the 910 * array of the held pages from uio, saved in the curthread->td_ma, 911 * instead of doing uiomove(). A helper function 912 * vn_io_fault_uiomove() converts uiomove request into 913 * uiomove_fromphys() over td_ma array. 914 * 915 * Since vnode locks do not cover the whole i/o anymore, rangelocks 916 * make the current i/o request atomic with respect to other i/os and 917 * truncations. 918 */ 919static int 920vn_io_fault(struct file *fp, struct uio *uio, struct ucred *active_cred, 921 int flags, struct thread *td) 922{ 923 vm_page_t ma[io_hold_cnt + 2]; 924 struct uio *uio_clone, short_uio; 925 struct iovec short_iovec[1]; 926 fo_rdwr_t *doio; 927 struct vnode *vp; 928 void *rl_cookie; 929 struct mount *mp; 930 vm_page_t *prev_td_ma; 931 int cnt, error, save, saveheld, prev_td_ma_cnt; 932 vm_offset_t addr, end; 933 vm_prot_t prot; 934 size_t len, resid; 935 ssize_t adv; 936 937 if (uio->uio_rw == UIO_READ) 938 doio = vn_read; 939 else 940 doio = vn_write; 941 vp = fp->f_vnode; 942 foffset_lock_uio(fp, uio, flags); 943 944 if (uio->uio_segflg != UIO_USERSPACE || vp->v_type != VREG || 945 ((mp = vp->v_mount) != NULL && 946 (mp->mnt_kern_flag & MNTK_NO_IOPF) == 0) || 947 !vn_io_fault_enable) { 948 error = doio(fp, uio, active_cred, flags | FOF_OFFSET, td); 949 goto out_last; 950 } 951 952 /* 953 * The UFS follows IO_UNIT directive and replays back both 954 * uio_offset and uio_resid if an error is encountered during the 955 * operation. But, since the iovec may be already advanced, 956 * uio is still in an inconsistent state. 957 * 958 * Cache a copy of the original uio, which is advanced to the redo 959 * point using UIO_NOCOPY below. 960 */ 961 uio_clone = cloneuio(uio); 962 resid = uio->uio_resid; 963 964 short_uio.uio_segflg = UIO_USERSPACE; 965 short_uio.uio_rw = uio->uio_rw; 966 short_uio.uio_td = uio->uio_td; 967 968 if (uio->uio_rw == UIO_READ) { 969 prot = VM_PROT_WRITE; 970 rl_cookie = vn_rangelock_rlock(vp, uio->uio_offset, 971 uio->uio_offset + uio->uio_resid); 972 } else { 973 prot = VM_PROT_READ; 974 if ((fp->f_flag & O_APPEND) != 0 || (flags & FOF_OFFSET) == 0) 975 /* For appenders, punt and lock the whole range. */ 976 rl_cookie = vn_rangelock_wlock(vp, 0, OFF_MAX); 977 else 978 rl_cookie = vn_rangelock_wlock(vp, uio->uio_offset, 979 uio->uio_offset + uio->uio_resid); 980 } 981 982 save = vm_fault_disable_pagefaults(); 983 error = doio(fp, uio, active_cred, flags | FOF_OFFSET, td); 984 if (error != EFAULT) 985 goto out; 986 987 atomic_add_long(&vn_io_faults_cnt, 1); 988 uio_clone->uio_segflg = UIO_NOCOPY; 989 uiomove(NULL, resid - uio->uio_resid, uio_clone); 990 uio_clone->uio_segflg = uio->uio_segflg; 991 992 saveheld = curthread_pflags_set(TDP_UIOHELD); 993 prev_td_ma = td->td_ma; 994 prev_td_ma_cnt = td->td_ma_cnt; 995 996 while (uio_clone->uio_resid != 0) { 997 len = uio_clone->uio_iov->iov_len; 998 if (len == 0) { 999 KASSERT(uio_clone->uio_iovcnt >= 1, 1000 ("iovcnt underflow")); 1001 uio_clone->uio_iov++; 1002 uio_clone->uio_iovcnt--; 1003 continue; 1004 } 1005 1006 addr = (vm_offset_t)uio_clone->uio_iov->iov_base; 1007 end = round_page(addr + len); 1008 cnt = howmany(end - trunc_page(addr), PAGE_SIZE); 1009 /* 1010 * A perfectly misaligned address and length could cause 1011 * both the start and the end of the chunk to use partial 1012 * page. +2 accounts for such a situation. 1013 */ 1014 if (cnt > io_hold_cnt + 2) { 1015 len = io_hold_cnt * PAGE_SIZE; 1016 KASSERT(howmany(round_page(addr + len) - 1017 trunc_page(addr), PAGE_SIZE) <= io_hold_cnt + 2, 1018 ("cnt overflow")); 1019 } 1020 cnt = vm_fault_quick_hold_pages(&td->td_proc->p_vmspace->vm_map, 1021 addr, len, prot, ma, io_hold_cnt + 2); 1022 if (cnt == -1) { 1023 error = EFAULT; 1024 break; 1025 } 1026 short_uio.uio_iov = &short_iovec[0]; 1027 short_iovec[0].iov_base = (void *)addr; 1028 short_uio.uio_iovcnt = 1; 1029 short_uio.uio_resid = short_iovec[0].iov_len = len; 1030 short_uio.uio_offset = uio_clone->uio_offset; 1031 td->td_ma = ma; 1032 td->td_ma_cnt = cnt; 1033 1034 error = doio(fp, &short_uio, active_cred, flags | FOF_OFFSET, 1035 td); 1036 vm_page_unhold_pages(ma, cnt); 1037 adv = len - short_uio.uio_resid; 1038 1039 uio_clone->uio_iov->iov_base = 1040 (char *)uio_clone->uio_iov->iov_base + adv; 1041 uio_clone->uio_iov->iov_len -= adv; 1042 uio_clone->uio_resid -= adv; 1043 uio_clone->uio_offset += adv; 1044 1045 uio->uio_resid -= adv; 1046 uio->uio_offset += adv; 1047 1048 if (error != 0 || adv == 0) 1049 break; 1050 } 1051 td->td_ma = prev_td_ma; 1052 td->td_ma_cnt = prev_td_ma_cnt; 1053 curthread_pflags_restore(saveheld); 1054out: 1055 vm_fault_enable_pagefaults(save); 1056 vn_rangelock_unlock(vp, rl_cookie); 1057 free(uio_clone, M_IOV); 1058out_last: 1059 foffset_unlock_uio(fp, uio, flags); 1060 return (error); 1061} 1062 1063/* 1064 * Helper function to perform the requested uiomove operation using 1065 * the held pages for io->uio_iov[0].iov_base buffer instead of 1066 * copyin/copyout. Access to the pages with uiomove_fromphys() 1067 * instead of iov_base prevents page faults that could occur due to 1068 * pmap_collect() invalidating the mapping created by 1069 * vm_fault_quick_hold_pages(), or pageout daemon, page laundry or 1070 * object cleanup revoking the write access from page mappings. 1071 * 1072 * Filesystems specified MNTK_NO_IOPF shall use vn_io_fault_uiomove() 1073 * instead of plain uiomove(). 1074 */ 1075int 1076vn_io_fault_uiomove(char *data, int xfersize, struct uio *uio) 1077{ 1078 struct uio transp_uio; 1079 struct iovec transp_iov[1]; 1080 struct thread *td; 1081 size_t adv; 1082 int error, pgadv; 1083 1084 td = curthread; 1085 if ((td->td_pflags & TDP_UIOHELD) == 0 || 1086 uio->uio_segflg != UIO_USERSPACE) 1087 return (uiomove(data, xfersize, uio)); 1088 1089 KASSERT(uio->uio_iovcnt == 1, ("uio_iovcnt %d", uio->uio_iovcnt)); 1090 transp_iov[0].iov_base = data; 1091 transp_uio.uio_iov = &transp_iov[0]; 1092 transp_uio.uio_iovcnt = 1; 1093 if (xfersize > uio->uio_resid) 1094 xfersize = uio->uio_resid; 1095 transp_uio.uio_resid = transp_iov[0].iov_len = xfersize; 1096 transp_uio.uio_offset = 0; 1097 transp_uio.uio_segflg = UIO_SYSSPACE; 1098 /* 1099 * Since transp_iov points to data, and td_ma page array 1100 * corresponds to original uio->uio_iov, we need to invert the 1101 * direction of the i/o operation as passed to 1102 * uiomove_fromphys(). 1103 */ 1104 switch (uio->uio_rw) { 1105 case UIO_WRITE: 1106 transp_uio.uio_rw = UIO_READ; 1107 break; 1108 case UIO_READ: 1109 transp_uio.uio_rw = UIO_WRITE; 1110 break; 1111 } 1112 transp_uio.uio_td = uio->uio_td; 1113 error = uiomove_fromphys(td->td_ma, 1114 ((vm_offset_t)uio->uio_iov->iov_base) & PAGE_MASK, 1115 xfersize, &transp_uio); 1116 adv = xfersize - transp_uio.uio_resid; 1117 pgadv = 1118 (((vm_offset_t)uio->uio_iov->iov_base + adv) >> PAGE_SHIFT) - 1119 (((vm_offset_t)uio->uio_iov->iov_base) >> PAGE_SHIFT); 1120 td->td_ma += pgadv; 1121 KASSERT(td->td_ma_cnt >= pgadv, ("consumed pages %d %d", td->td_ma_cnt, 1122 pgadv)); 1123 td->td_ma_cnt -= pgadv; 1124 uio->uio_iov->iov_base = (char *)uio->uio_iov->iov_base + adv; 1125 uio->uio_iov->iov_len -= adv; 1126 uio->uio_resid -= adv; 1127 uio->uio_offset += adv; 1128 return (error); 1129} 1130 1131int 1132vn_io_fault_pgmove(vm_page_t ma[], vm_offset_t offset, int xfersize, 1133 struct uio *uio) 1134{ 1135 struct thread *td; 1136 vm_offset_t iov_base; 1137 int cnt, pgadv; 1138 1139 td = curthread; 1140 if ((td->td_pflags & TDP_UIOHELD) == 0 || 1141 uio->uio_segflg != UIO_USERSPACE) 1142 return (uiomove_fromphys(ma, offset, xfersize, uio)); 1143 1144 KASSERT(uio->uio_iovcnt == 1, ("uio_iovcnt %d", uio->uio_iovcnt)); 1145 cnt = xfersize > uio->uio_resid ? uio->uio_resid : xfersize; 1146 iov_base = (vm_offset_t)uio->uio_iov->iov_base; 1147 switch (uio->uio_rw) { 1148 case UIO_WRITE: 1149 pmap_copy_pages(td->td_ma, iov_base & PAGE_MASK, ma, 1150 offset, cnt); 1151 break; 1152 case UIO_READ: 1153 pmap_copy_pages(ma, offset, td->td_ma, iov_base & PAGE_MASK, 1154 cnt); 1155 break; 1156 } 1157 pgadv = ((iov_base + cnt) >> PAGE_SHIFT) - (iov_base >> PAGE_SHIFT); 1158 td->td_ma += pgadv; 1159 KASSERT(td->td_ma_cnt >= pgadv, ("consumed pages %d %d", td->td_ma_cnt, 1160 pgadv)); 1161 td->td_ma_cnt -= pgadv; 1162 uio->uio_iov->iov_base = (char *)(iov_base + cnt); 1163 uio->uio_iov->iov_len -= cnt; 1164 uio->uio_resid -= cnt; 1165 uio->uio_offset += cnt; 1166 return (0); 1167} 1168 1169 1170/* 1171 * File table truncate routine. 1172 */ 1173static int 1174vn_truncate(struct file *fp, off_t length, struct ucred *active_cred, 1175 struct thread *td) 1176{ 1177 struct vattr vattr; 1178 struct mount *mp; 1179 struct vnode *vp; 1180 void *rl_cookie; 1181 int error; 1182 1183 vp = fp->f_vnode; 1184 1185 /* 1186 * Lock the whole range for truncation. Otherwise split i/o 1187 * might happen partly before and partly after the truncation. 1188 */ 1189 rl_cookie = vn_rangelock_wlock(vp, 0, OFF_MAX); 1190 error = vn_start_write(vp, &mp, V_WAIT | PCATCH); 1191 if (error) 1192 goto out1; 1193 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 1194 if (vp->v_type == VDIR) { 1195 error = EISDIR; 1196 goto out; 1197 } 1198#ifdef MAC 1199 error = mac_vnode_check_write(active_cred, fp->f_cred, vp); 1200 if (error) 1201 goto out; 1202#endif 1203 error = vn_writechk(vp); 1204 if (error == 0) { 1205 VATTR_NULL(&vattr); 1206 vattr.va_size = length; 1207 error = VOP_SETATTR(vp, &vattr, fp->f_cred); 1208 } 1209out: 1210 VOP_UNLOCK(vp, 0); 1211 vn_finished_write(mp); 1212out1: 1213 vn_rangelock_unlock(vp, rl_cookie); 1214 return (error); 1215} 1216 1217/* 1218 * File table vnode stat routine. 1219 */ 1220static int 1221vn_statfile(fp, sb, active_cred, td) 1222 struct file *fp; 1223 struct stat *sb; 1224 struct ucred *active_cred; 1225 struct thread *td; 1226{ 1227 struct vnode *vp = fp->f_vnode; 1228 int error; 1229 1230 vn_lock(vp, LK_SHARED | LK_RETRY); 1231 error = vn_stat(vp, sb, active_cred, fp->f_cred, td); 1232 VOP_UNLOCK(vp, 0); 1233 1234 return (error); 1235} 1236 1237/* 1238 * Stat a vnode; implementation for the stat syscall 1239 */ 1240int 1241vn_stat(vp, sb, active_cred, file_cred, td) 1242 struct vnode *vp; 1243 register struct stat *sb; 1244 struct ucred *active_cred; 1245 struct ucred *file_cred; 1246 struct thread *td; 1247{ 1248 struct vattr vattr; 1249 register struct vattr *vap; 1250 int error; 1251 u_short mode; 1252 1253#ifdef MAC 1254 error = mac_vnode_check_stat(active_cred, file_cred, vp); 1255 if (error) 1256 return (error); 1257#endif 1258 1259 vap = &vattr; 1260 1261 /* 1262 * Initialize defaults for new and unusual fields, so that file 1263 * systems which don't support these fields don't need to know 1264 * about them. 1265 */ 1266 vap->va_birthtime.tv_sec = -1; 1267 vap->va_birthtime.tv_nsec = 0; 1268 vap->va_fsid = VNOVAL; 1269 vap->va_rdev = NODEV; 1270 1271 error = VOP_GETATTR(vp, vap, active_cred); 1272 if (error) 1273 return (error); 1274 1275 /* 1276 * Zero the spare stat fields 1277 */ 1278 bzero(sb, sizeof *sb); 1279 1280 /* 1281 * Copy from vattr table 1282 */ 1283 if (vap->va_fsid != VNOVAL) 1284 sb->st_dev = vap->va_fsid; 1285 else 1286 sb->st_dev = vp->v_mount->mnt_stat.f_fsid.val[0]; 1287 sb->st_ino = vap->va_fileid; 1288 mode = vap->va_mode; 1289 switch (vap->va_type) { 1290 case VREG: 1291 mode |= S_IFREG; 1292 break; 1293 case VDIR: 1294 mode |= S_IFDIR; 1295 break; 1296 case VBLK: 1297 mode |= S_IFBLK; 1298 break; 1299 case VCHR: 1300 mode |= S_IFCHR; 1301 break; 1302 case VLNK: 1303 mode |= S_IFLNK; 1304 break; 1305 case VSOCK: 1306 mode |= S_IFSOCK; 1307 break; 1308 case VFIFO: 1309 mode |= S_IFIFO; 1310 break; 1311 default: 1312 return (EBADF); 1313 }; 1314 sb->st_mode = mode; 1315 sb->st_nlink = vap->va_nlink; 1316 sb->st_uid = vap->va_uid; 1317 sb->st_gid = vap->va_gid; 1318 sb->st_rdev = vap->va_rdev; 1319 if (vap->va_size > OFF_MAX) 1320 return (EOVERFLOW); 1321 sb->st_size = vap->va_size; 1322 sb->st_atim = vap->va_atime; 1323 sb->st_mtim = vap->va_mtime; 1324 sb->st_ctim = vap->va_ctime; 1325 sb->st_birthtim = vap->va_birthtime; 1326 1327 /* 1328 * According to www.opengroup.org, the meaning of st_blksize is 1329 * "a filesystem-specific preferred I/O block size for this 1330 * object. In some filesystem types, this may vary from file 1331 * to file" 1332 * Use miminum/default of PAGE_SIZE (e.g. for VCHR). 1333 */ 1334 1335 sb->st_blksize = max(PAGE_SIZE, vap->va_blocksize); 1336 1337 sb->st_flags = vap->va_flags; 1338 if (priv_check(td, PRIV_VFS_GENERATION)) 1339 sb->st_gen = 0; 1340 else 1341 sb->st_gen = vap->va_gen; 1342 1343 sb->st_blocks = vap->va_bytes / S_BLKSIZE; 1344 return (0); 1345} 1346 1347/* 1348 * File table vnode ioctl routine. 1349 */ 1350static int 1351vn_ioctl(fp, com, data, active_cred, td) 1352 struct file *fp; 1353 u_long com; 1354 void *data; 1355 struct ucred *active_cred; 1356 struct thread *td; 1357{ 1358 struct vattr vattr; 1359 struct vnode *vp; 1360 int error; 1361 1362 vp = fp->f_vnode; 1363 switch (vp->v_type) { 1364 case VDIR: 1365 case VREG: 1366 switch (com) { 1367 case FIONREAD: 1368 vn_lock(vp, LK_SHARED | LK_RETRY); 1369 error = VOP_GETATTR(vp, &vattr, active_cred); 1370 VOP_UNLOCK(vp, 0); 1371 if (error == 0) 1372 *(int *)data = vattr.va_size - fp->f_offset; 1373 return (error); 1374 case FIONBIO: 1375 case FIOASYNC: 1376 return (0); 1377 default: 1378 return (VOP_IOCTL(vp, com, data, fp->f_flag, 1379 active_cred, td)); 1380 } 1381 default: 1382 return (ENOTTY); 1383 } 1384} 1385 1386/* 1387 * File table vnode poll routine. 1388 */ 1389static int 1390vn_poll(fp, events, active_cred, td) 1391 struct file *fp; 1392 int events; 1393 struct ucred *active_cred; 1394 struct thread *td; 1395{ 1396 struct vnode *vp; 1397 int error; 1398 1399 vp = fp->f_vnode; 1400#ifdef MAC 1401 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 1402 error = mac_vnode_check_poll(active_cred, fp->f_cred, vp); 1403 VOP_UNLOCK(vp, 0); 1404 if (!error) 1405#endif 1406 1407 error = VOP_POLL(vp, events, fp->f_cred, td); 1408 return (error); 1409} 1410 1411/* 1412 * Acquire the requested lock and then check for validity. LK_RETRY 1413 * permits vn_lock to return doomed vnodes. 1414 */ 1415int 1416_vn_lock(struct vnode *vp, int flags, char *file, int line) 1417{ 1418 int error; 1419 1420 VNASSERT((flags & LK_TYPE_MASK) != 0, vp, 1421 ("vn_lock called with no locktype.")); 1422 do { 1423#ifdef DEBUG_VFS_LOCKS 1424 KASSERT(vp->v_holdcnt != 0, 1425 ("vn_lock %p: zero hold count", vp)); 1426#endif 1427 error = VOP_LOCK1(vp, flags, file, line); 1428 flags &= ~LK_INTERLOCK; /* Interlock is always dropped. */ 1429 KASSERT((flags & LK_RETRY) == 0 || error == 0, 1430 ("LK_RETRY set with incompatible flags (0x%x) or an error occured (%d)", 1431 flags, error)); 1432 /* 1433 * Callers specify LK_RETRY if they wish to get dead vnodes. 1434 * If RETRY is not set, we return ENOENT instead. 1435 */ 1436 if (error == 0 && vp->v_iflag & VI_DOOMED && 1437 (flags & LK_RETRY) == 0) { 1438 VOP_UNLOCK(vp, 0); 1439 error = ENOENT; 1440 break; 1441 } 1442 } while (flags & LK_RETRY && error != 0); 1443 return (error); 1444} 1445 1446/* 1447 * File table vnode close routine. 1448 */ 1449static int 1450vn_closefile(fp, td) 1451 struct file *fp; 1452 struct thread *td; 1453{ 1454 struct vnode *vp; 1455 struct flock lf; 1456 int error; 1457 1458 vp = fp->f_vnode; 1459 fp->f_ops = &badfileops; 1460 1461 if (fp->f_type == DTYPE_VNODE && fp->f_flag & FHASLOCK) 1462 vref(vp); 1463 1464 error = vn_close(vp, fp->f_flag, fp->f_cred, td); 1465 1466 if (fp->f_type == DTYPE_VNODE && fp->f_flag & FHASLOCK) { 1467 lf.l_whence = SEEK_SET; 1468 lf.l_start = 0; 1469 lf.l_len = 0; 1470 lf.l_type = F_UNLCK; 1471 (void) VOP_ADVLOCK(vp, fp, F_UNLCK, &lf, F_FLOCK); 1472 vrele(vp); 1473 } 1474 return (error); 1475} 1476 1477/* 1478 * Preparing to start a filesystem write operation. If the operation is 1479 * permitted, then we bump the count of operations in progress and 1480 * proceed. If a suspend request is in progress, we wait until the 1481 * suspension is over, and then proceed. 1482 */ 1483static int 1484vn_start_write_locked(struct mount *mp, int flags) 1485{ 1486 int error; 1487 1488 mtx_assert(MNT_MTX(mp), MA_OWNED); 1489 error = 0; 1490 1491 /* 1492 * Check on status of suspension. 1493 */ 1494 if ((curthread->td_pflags & TDP_IGNSUSP) == 0 || 1495 mp->mnt_susp_owner != curthread) { 1496 while ((mp->mnt_kern_flag & MNTK_SUSPEND) != 0) { 1497 if (flags & V_NOWAIT) { 1498 error = EWOULDBLOCK; 1499 goto unlock; 1500 } 1501 error = msleep(&mp->mnt_flag, MNT_MTX(mp), 1502 (PUSER - 1) | (flags & PCATCH), "suspfs", 0); 1503 if (error) 1504 goto unlock; 1505 } 1506 } 1507 if (flags & V_XSLEEP) 1508 goto unlock; 1509 mp->mnt_writeopcount++; 1510unlock: 1511 if (error != 0 || (flags & V_XSLEEP) != 0) 1512 MNT_REL(mp); 1513 MNT_IUNLOCK(mp); 1514 return (error); 1515} 1516 1517int 1518vn_start_write(vp, mpp, flags) 1519 struct vnode *vp; 1520 struct mount **mpp; 1521 int flags; 1522{ 1523 struct mount *mp; 1524 int error; 1525 1526 error = 0; 1527 /* 1528 * If a vnode is provided, get and return the mount point that 1529 * to which it will write. 1530 */ 1531 if (vp != NULL) { 1532 if ((error = VOP_GETWRITEMOUNT(vp, mpp)) != 0) { 1533 *mpp = NULL; 1534 if (error != EOPNOTSUPP) 1535 return (error); 1536 return (0); 1537 } 1538 } 1539 if ((mp = *mpp) == NULL) 1540 return (0); 1541 1542 /* 1543 * VOP_GETWRITEMOUNT() returns with the mp refcount held through 1544 * a vfs_ref(). 1545 * As long as a vnode is not provided we need to acquire a 1546 * refcount for the provided mountpoint too, in order to 1547 * emulate a vfs_ref(). 1548 */ 1549 MNT_ILOCK(mp); 1550 if (vp == NULL) 1551 MNT_REF(mp); 1552 1553 return (vn_start_write_locked(mp, flags)); 1554} 1555 1556/* 1557 * Secondary suspension. Used by operations such as vop_inactive 1558 * routines that are needed by the higher level functions. These 1559 * are allowed to proceed until all the higher level functions have 1560 * completed (indicated by mnt_writeopcount dropping to zero). At that 1561 * time, these operations are halted until the suspension is over. 1562 */ 1563int 1564vn_start_secondary_write(vp, mpp, flags) 1565 struct vnode *vp; 1566 struct mount **mpp; 1567 int flags; 1568{ 1569 struct mount *mp; 1570 int error; 1571 1572 retry: 1573 if (vp != NULL) { 1574 if ((error = VOP_GETWRITEMOUNT(vp, mpp)) != 0) { 1575 *mpp = NULL; 1576 if (error != EOPNOTSUPP) 1577 return (error); 1578 return (0); 1579 } 1580 } 1581 /* 1582 * If we are not suspended or have not yet reached suspended 1583 * mode, then let the operation proceed. 1584 */ 1585 if ((mp = *mpp) == NULL) 1586 return (0); 1587 1588 /* 1589 * VOP_GETWRITEMOUNT() returns with the mp refcount held through 1590 * a vfs_ref(). 1591 * As long as a vnode is not provided we need to acquire a 1592 * refcount for the provided mountpoint too, in order to 1593 * emulate a vfs_ref(). 1594 */ 1595 MNT_ILOCK(mp); 1596 if (vp == NULL) 1597 MNT_REF(mp); 1598 if ((mp->mnt_kern_flag & (MNTK_SUSPENDED | MNTK_SUSPEND2)) == 0) { 1599 mp->mnt_secondary_writes++; 1600 mp->mnt_secondary_accwrites++; 1601 MNT_IUNLOCK(mp); 1602 return (0); 1603 } 1604 if (flags & V_NOWAIT) { 1605 MNT_REL(mp); 1606 MNT_IUNLOCK(mp); 1607 return (EWOULDBLOCK); 1608 } 1609 /* 1610 * Wait for the suspension to finish. 1611 */ 1612 error = msleep(&mp->mnt_flag, MNT_MTX(mp), 1613 (PUSER - 1) | (flags & PCATCH) | PDROP, "suspfs", 0); 1614 vfs_rel(mp); 1615 if (error == 0) 1616 goto retry; 1617 return (error); 1618} 1619 1620/* 1621 * Filesystem write operation has completed. If we are suspending and this 1622 * operation is the last one, notify the suspender that the suspension is 1623 * now in effect. 1624 */ 1625void 1626vn_finished_write(mp) 1627 struct mount *mp; 1628{ 1629 if (mp == NULL) 1630 return; 1631 MNT_ILOCK(mp); 1632 MNT_REL(mp); 1633 mp->mnt_writeopcount--; 1634 if (mp->mnt_writeopcount < 0) 1635 panic("vn_finished_write: neg cnt"); 1636 if ((mp->mnt_kern_flag & MNTK_SUSPEND) != 0 && 1637 mp->mnt_writeopcount <= 0) 1638 wakeup(&mp->mnt_writeopcount); 1639 MNT_IUNLOCK(mp); 1640} 1641 1642 1643/* 1644 * Filesystem secondary write operation has completed. If we are 1645 * suspending and this operation is the last one, notify the suspender 1646 * that the suspension is now in effect. 1647 */ 1648void 1649vn_finished_secondary_write(mp) 1650 struct mount *mp; 1651{ 1652 if (mp == NULL) 1653 return; 1654 MNT_ILOCK(mp); 1655 MNT_REL(mp); 1656 mp->mnt_secondary_writes--; 1657 if (mp->mnt_secondary_writes < 0) 1658 panic("vn_finished_secondary_write: neg cnt"); 1659 if ((mp->mnt_kern_flag & MNTK_SUSPEND) != 0 && 1660 mp->mnt_secondary_writes <= 0) 1661 wakeup(&mp->mnt_secondary_writes); 1662 MNT_IUNLOCK(mp); 1663} 1664 1665 1666 1667/* 1668 * Request a filesystem to suspend write operations. 1669 */ 1670int 1671vfs_write_suspend(struct mount *mp, int flags) 1672{ 1673 int error; 1674 1675 MNT_ILOCK(mp); 1676 if (mp->mnt_susp_owner == curthread) { 1677 MNT_IUNLOCK(mp); 1678 return (EALREADY); 1679 } 1680 while (mp->mnt_kern_flag & MNTK_SUSPEND) 1681 msleep(&mp->mnt_flag, MNT_MTX(mp), PUSER - 1, "wsuspfs", 0); 1682 1683 /* 1684 * Unmount holds a write reference on the mount point. If we 1685 * own busy reference and drain for writers, we deadlock with 1686 * the reference draining in the unmount path. Callers of 1687 * vfs_write_suspend() must specify VS_SKIP_UNMOUNT if 1688 * vfs_busy() reference is owned and caller is not in the 1689 * unmount context. 1690 */ 1691 if ((flags & VS_SKIP_UNMOUNT) != 0 && 1692 (mp->mnt_kern_flag & MNTK_UNMOUNT) != 0) { 1693 MNT_IUNLOCK(mp); 1694 return (EBUSY); 1695 } 1696 1697 mp->mnt_kern_flag |= MNTK_SUSPEND; 1698 mp->mnt_susp_owner = curthread; 1699 if (mp->mnt_writeopcount > 0) 1700 (void) msleep(&mp->mnt_writeopcount, 1701 MNT_MTX(mp), (PUSER - 1)|PDROP, "suspwt", 0); 1702 else 1703 MNT_IUNLOCK(mp); 1704 if ((error = VFS_SYNC(mp, MNT_SUSPEND)) != 0) 1705 vfs_write_resume(mp, 0); 1706 return (error); 1707} 1708 1709/* 1710 * Request a filesystem to resume write operations. 1711 */ 1712void 1713vfs_write_resume(struct mount *mp, int flags) 1714{ 1715 1716 MNT_ILOCK(mp); 1717 if ((mp->mnt_kern_flag & MNTK_SUSPEND) != 0) { 1718 KASSERT(mp->mnt_susp_owner == curthread, ("mnt_susp_owner")); 1719 mp->mnt_kern_flag &= ~(MNTK_SUSPEND | MNTK_SUSPEND2 | 1720 MNTK_SUSPENDED); 1721 mp->mnt_susp_owner = NULL; 1722 wakeup(&mp->mnt_writeopcount); 1723 wakeup(&mp->mnt_flag); 1724 curthread->td_pflags &= ~TDP_IGNSUSP; 1725 if ((flags & VR_START_WRITE) != 0) { 1726 MNT_REF(mp); 1727 mp->mnt_writeopcount++; 1728 } 1729 MNT_IUNLOCK(mp); 1730 if ((flags & VR_NO_SUSPCLR) == 0) 1731 VFS_SUSP_CLEAN(mp); 1732 } else if ((flags & VR_START_WRITE) != 0) { 1733 MNT_REF(mp); 1734 vn_start_write_locked(mp, 0); 1735 } else { 1736 MNT_IUNLOCK(mp); 1737 } 1738} 1739 1740/* 1741 * Implement kqueues for files by translating it to vnode operation. 1742 */ 1743static int 1744vn_kqfilter(struct file *fp, struct knote *kn) 1745{ 1746 1747 return (VOP_KQFILTER(fp->f_vnode, kn)); 1748} 1749 1750/* 1751 * Simplified in-kernel wrapper calls for extended attribute access. 1752 * Both calls pass in a NULL credential, authorizing as "kernel" access. 1753 * Set IO_NODELOCKED in ioflg if the vnode is already locked. 1754 */ 1755int 1756vn_extattr_get(struct vnode *vp, int ioflg, int attrnamespace, 1757 const char *attrname, int *buflen, char *buf, struct thread *td) 1758{ 1759 struct uio auio; 1760 struct iovec iov; 1761 int error; 1762 1763 iov.iov_len = *buflen; 1764 iov.iov_base = buf; 1765 1766 auio.uio_iov = &iov; 1767 auio.uio_iovcnt = 1; 1768 auio.uio_rw = UIO_READ; 1769 auio.uio_segflg = UIO_SYSSPACE; 1770 auio.uio_td = td; 1771 auio.uio_offset = 0; 1772 auio.uio_resid = *buflen; 1773 1774 if ((ioflg & IO_NODELOCKED) == 0) 1775 vn_lock(vp, LK_SHARED | LK_RETRY); 1776 1777 ASSERT_VOP_LOCKED(vp, "IO_NODELOCKED with no vp lock held"); 1778 1779 /* authorize attribute retrieval as kernel */ 1780 error = VOP_GETEXTATTR(vp, attrnamespace, attrname, &auio, NULL, NULL, 1781 td); 1782 1783 if ((ioflg & IO_NODELOCKED) == 0) 1784 VOP_UNLOCK(vp, 0); 1785 1786 if (error == 0) { 1787 *buflen = *buflen - auio.uio_resid; 1788 } 1789 1790 return (error); 1791} 1792 1793/* 1794 * XXX failure mode if partially written? 1795 */ 1796int 1797vn_extattr_set(struct vnode *vp, int ioflg, int attrnamespace, 1798 const char *attrname, int buflen, char *buf, struct thread *td) 1799{ 1800 struct uio auio; 1801 struct iovec iov; 1802 struct mount *mp; 1803 int error; 1804 1805 iov.iov_len = buflen; 1806 iov.iov_base = buf; 1807 1808 auio.uio_iov = &iov; 1809 auio.uio_iovcnt = 1; 1810 auio.uio_rw = UIO_WRITE; 1811 auio.uio_segflg = UIO_SYSSPACE; 1812 auio.uio_td = td; 1813 auio.uio_offset = 0; 1814 auio.uio_resid = buflen; 1815 1816 if ((ioflg & IO_NODELOCKED) == 0) { 1817 if ((error = vn_start_write(vp, &mp, V_WAIT)) != 0) 1818 return (error); 1819 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 1820 } 1821 1822 ASSERT_VOP_LOCKED(vp, "IO_NODELOCKED with no vp lock held"); 1823 1824 /* authorize attribute setting as kernel */ 1825 error = VOP_SETEXTATTR(vp, attrnamespace, attrname, &auio, NULL, td); 1826 1827 if ((ioflg & IO_NODELOCKED) == 0) { 1828 vn_finished_write(mp); 1829 VOP_UNLOCK(vp, 0); 1830 } 1831 1832 return (error); 1833} 1834 1835int 1836vn_extattr_rm(struct vnode *vp, int ioflg, int attrnamespace, 1837 const char *attrname, struct thread *td) 1838{ 1839 struct mount *mp; 1840 int error; 1841 1842 if ((ioflg & IO_NODELOCKED) == 0) { 1843 if ((error = vn_start_write(vp, &mp, V_WAIT)) != 0) 1844 return (error); 1845 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 1846 } 1847 1848 ASSERT_VOP_LOCKED(vp, "IO_NODELOCKED with no vp lock held"); 1849 1850 /* authorize attribute removal as kernel */ 1851 error = VOP_DELETEEXTATTR(vp, attrnamespace, attrname, NULL, td); 1852 if (error == EOPNOTSUPP) 1853 error = VOP_SETEXTATTR(vp, attrnamespace, attrname, NULL, 1854 NULL, td); 1855 1856 if ((ioflg & IO_NODELOCKED) == 0) { 1857 vn_finished_write(mp); 1858 VOP_UNLOCK(vp, 0); 1859 } 1860 1861 return (error); 1862} 1863 1864int 1865vn_vget_ino(struct vnode *vp, ino_t ino, int lkflags, struct vnode **rvp) 1866{ 1867 struct mount *mp; 1868 int ltype, error; 1869 1870 mp = vp->v_mount; 1871 ltype = VOP_ISLOCKED(vp); 1872 KASSERT(ltype == LK_EXCLUSIVE || ltype == LK_SHARED, 1873 ("vn_vget_ino: vp not locked")); 1874 error = vfs_busy(mp, MBF_NOWAIT); 1875 if (error != 0) { 1876 vfs_ref(mp); 1877 VOP_UNLOCK(vp, 0); 1878 error = vfs_busy(mp, 0); 1879 vn_lock(vp, ltype | LK_RETRY); 1880 vfs_rel(mp); 1881 if (error != 0) 1882 return (ENOENT); 1883 if (vp->v_iflag & VI_DOOMED) { 1884 vfs_unbusy(mp); 1885 return (ENOENT); 1886 } 1887 } 1888 VOP_UNLOCK(vp, 0); 1889 error = VFS_VGET(mp, ino, lkflags, rvp); 1890 vfs_unbusy(mp); 1891 vn_lock(vp, ltype | LK_RETRY); 1892 if (vp->v_iflag & VI_DOOMED) { 1893 if (error == 0) 1894 vput(*rvp); 1895 error = ENOENT; 1896 } 1897 return (error); 1898} 1899 1900int 1901vn_rlimit_fsize(const struct vnode *vp, const struct uio *uio, 1902 const struct thread *td) 1903{ 1904 1905 if (vp->v_type != VREG || td == NULL) 1906 return (0); 1907 PROC_LOCK(td->td_proc); 1908 if ((uoff_t)uio->uio_offset + uio->uio_resid > 1909 lim_cur(td->td_proc, RLIMIT_FSIZE)) { 1910 kern_psignal(td->td_proc, SIGXFSZ); 1911 PROC_UNLOCK(td->td_proc); 1912 return (EFBIG); 1913 } 1914 PROC_UNLOCK(td->td_proc); 1915 return (0); 1916} 1917 1918int 1919vn_chmod(struct file *fp, mode_t mode, struct ucred *active_cred, 1920 struct thread *td) 1921{ 1922 struct vnode *vp; 1923 1924 vp = fp->f_vnode; 1925#ifdef AUDIT 1926 vn_lock(vp, LK_SHARED | LK_RETRY); 1927 AUDIT_ARG_VNODE1(vp); 1928 VOP_UNLOCK(vp, 0); 1929#endif 1930 return (setfmode(td, active_cred, vp, mode)); 1931} 1932 1933int 1934vn_chown(struct file *fp, uid_t uid, gid_t gid, struct ucred *active_cred, 1935 struct thread *td) 1936{ 1937 struct vnode *vp; 1938 1939 vp = fp->f_vnode; 1940#ifdef AUDIT 1941 vn_lock(vp, LK_SHARED | LK_RETRY); 1942 AUDIT_ARG_VNODE1(vp); 1943 VOP_UNLOCK(vp, 0); 1944#endif 1945 return (setfown(td, active_cred, vp, uid, gid)); 1946} 1947 1948void 1949vn_pages_remove(struct vnode *vp, vm_pindex_t start, vm_pindex_t end) 1950{ 1951 vm_object_t object; 1952 1953 if ((object = vp->v_object) == NULL) 1954 return; 1955 VM_OBJECT_WLOCK(object); 1956 vm_object_page_remove(object, start, end, 0); 1957 VM_OBJECT_WUNLOCK(object); 1958} 1959 1960int 1961vn_bmap_seekhole(struct vnode *vp, u_long cmd, off_t *off, struct ucred *cred) 1962{ 1963 struct vattr va; 1964 daddr_t bn, bnp; 1965 uint64_t bsize; 1966 off_t noff; 1967 int error; 1968 1969 KASSERT(cmd == FIOSEEKHOLE || cmd == FIOSEEKDATA, 1970 ("Wrong command %lu", cmd)); 1971 1972 if (vn_lock(vp, LK_SHARED) != 0) 1973 return (EBADF); 1974 if (vp->v_type != VREG) { 1975 error = ENOTTY; 1976 goto unlock; 1977 } 1978 error = VOP_GETATTR(vp, &va, cred); 1979 if (error != 0) 1980 goto unlock; 1981 noff = *off; 1982 if (noff >= va.va_size) { 1983 error = ENXIO; 1984 goto unlock; 1985 } 1986 bsize = vp->v_mount->mnt_stat.f_iosize; 1987 for (bn = noff / bsize; noff < va.va_size; bn++, noff += bsize) { 1988 error = VOP_BMAP(vp, bn, NULL, &bnp, NULL, NULL); 1989 if (error == EOPNOTSUPP) { 1990 error = ENOTTY; 1991 goto unlock; 1992 } 1993 if ((bnp == -1 && cmd == FIOSEEKHOLE) || 1994 (bnp != -1 && cmd == FIOSEEKDATA)) { 1995 noff = bn * bsize; 1996 if (noff < *off) 1997 noff = *off; 1998 goto unlock; 1999 } 2000 } 2001 if (noff > va.va_size) 2002 noff = va.va_size; 2003 /* noff == va.va_size. There is an implicit hole at the end of file. */ 2004 if (cmd == FIOSEEKDATA) 2005 error = ENXIO; 2006unlock: 2007 VOP_UNLOCK(vp, 0); 2008 if (error == 0) 2009 *off = noff; 2010 return (error); 2011} 2012