1 /*- 2 * SPDX-License-Identifier: BSD-3-Clause 3 * 4 * Copyright (c) 1982, 1986, 1989, 1993 5 * The Regents of the University of California. All rights reserved. 6 * (c) UNIX System Laboratories, Inc. 7 * All or some portions of this file are derived from material licensed 8 * to the University of California by American Telephone and Telegraph 9 * Co. or Unix System Laboratories, Inc. and are reproduced herein with 10 * the permission of UNIX System Laboratories, Inc. 11 * 12 * Copyright (c) 2012 Konstantin Belousov <kib@FreeBSD.org> 13 * Copyright (c) 2013, 2014 The FreeBSD Foundation 14 * 15 * Portions of this software were developed by Konstantin Belousov 16 * under sponsorship from the FreeBSD Foundation. 17 * 18 * Redistribution and use in source and binary forms, with or without 19 * modification, are permitted provided that the following conditions 20 * are met: 21 * 1. Redistributions of source code must retain the above copyright 22 * notice, this list of conditions and the following disclaimer. 23 * 2. Redistributions in binary form must reproduce the above copyright 24 * notice, this list of conditions and the following disclaimer in the 25 * documentation and/or other materials provided with the distribution. 26 * 3. Neither the name of the University nor the names of its contributors 27 * may be used to endorse or promote products derived from this software 28 * without specific prior written permission. 29 * 30 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 31 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 32 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 33 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 34 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 35 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 36 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 37 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 38 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 39 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 40 * SUCH DAMAGE. 41 * 42 * @(#)vfs_vnops.c 8.2 (Berkeley) 1/21/94 43 */ 44 45 #include <sys/cdefs.h> 46 __FBSDID("$FreeBSD$"); 47 48 #include "opt_hwpmc_hooks.h" 49 50 #include <sys/param.h> 51 #include <sys/systm.h> 52 #include <sys/disk.h> 53 #include <sys/fail.h> 54 #include <sys/fcntl.h> 55 #include <sys/file.h> 56 #include <sys/kdb.h> 57 #include <sys/ktr.h> 58 #include <sys/stat.h> 59 #include <sys/priv.h> 60 #include <sys/proc.h> 61 #include <sys/limits.h> 62 #include <sys/lock.h> 63 #include <sys/mman.h> 64 #include <sys/mount.h> 65 #include <sys/mutex.h> 66 #include <sys/namei.h> 67 #include <sys/vnode.h> 68 #include <sys/bio.h> 69 #include <sys/buf.h> 70 #include <sys/filio.h> 71 #include <sys/resourcevar.h> 72 #include <sys/rwlock.h> 73 #include <sys/sx.h> 74 #include <sys/sleepqueue.h> 75 #include <sys/sysctl.h> 76 #include <sys/ttycom.h> 77 #include <sys/conf.h> 78 #include <sys/syslog.h> 79 #include <sys/unistd.h> 80 #include <sys/user.h> 81 82 #include <security/audit/audit.h> 83 #include <security/mac/mac_framework.h> 84 85 #include <vm/vm.h> 86 #include <vm/vm_extern.h> 87 #include <vm/pmap.h> 88 #include <vm/vm_map.h> 89 #include <vm/vm_object.h> 90 #include <vm/vm_page.h> 91 #include <vm/vm_pager.h> 92 93 #ifdef HWPMC_HOOKS 94 #include <sys/pmckern.h> 95 #endif 96 97 static fo_rdwr_t vn_read; 98 static fo_rdwr_t vn_write; 99 static fo_rdwr_t vn_io_fault; 100 static fo_truncate_t vn_truncate; 101 static fo_ioctl_t vn_ioctl; 102 static fo_poll_t vn_poll; 103 static fo_kqfilter_t vn_kqfilter; 104 static fo_stat_t vn_statfile; 105 static fo_close_t vn_closefile; 106 static fo_mmap_t vn_mmap; 107 static fo_fallocate_t vn_fallocate; 108 109 struct fileops vnops = { 110 .fo_read = vn_io_fault, 111 .fo_write = vn_io_fault, 112 .fo_truncate = vn_truncate, 113 .fo_ioctl = vn_ioctl, 114 .fo_poll = vn_poll, 115 .fo_kqfilter = vn_kqfilter, 116 .fo_stat = vn_statfile, 117 .fo_close = vn_closefile, 118 .fo_chmod = vn_chmod, 119 .fo_chown = vn_chown, 120 .fo_sendfile = vn_sendfile, 121 .fo_seek = vn_seek, 122 .fo_fill_kinfo = vn_fill_kinfo, 123 .fo_mmap = vn_mmap, 124 .fo_fallocate = vn_fallocate, 125 .fo_flags = DFLAG_PASSABLE | DFLAG_SEEKABLE 126 }; 127 128 static const int io_hold_cnt = 16; 129 static int vn_io_fault_enable = 1; 130 SYSCTL_INT(_debug, OID_AUTO, vn_io_fault_enable, CTLFLAG_RW, 131 &vn_io_fault_enable, 0, "Enable vn_io_fault lock avoidance"); 132 static int vn_io_fault_prefault = 0; 133 SYSCTL_INT(_debug, OID_AUTO, vn_io_fault_prefault, CTLFLAG_RW, 134 &vn_io_fault_prefault, 0, "Enable vn_io_fault prefaulting"); 135 static u_long vn_io_faults_cnt; 136 SYSCTL_ULONG(_debug, OID_AUTO, vn_io_faults, CTLFLAG_RD, 137 &vn_io_faults_cnt, 0, "Count of vn_io_fault lock avoidance triggers"); 138 139 /* 140 * Returns true if vn_io_fault mode of handling the i/o request should 141 * be used. 142 */ 143 static bool 144 do_vn_io_fault(struct vnode *vp, struct uio *uio) 145 { 146 struct mount *mp; 147 148 return (uio->uio_segflg == UIO_USERSPACE && vp->v_type == VREG && 149 (mp = vp->v_mount) != NULL && 150 (mp->mnt_kern_flag & MNTK_NO_IOPF) != 0 && vn_io_fault_enable); 151 } 152 153 /* 154 * Structure used to pass arguments to vn_io_fault1(), to do either 155 * file- or vnode-based I/O calls. 156 */ 157 struct vn_io_fault_args { 158 enum { 159 VN_IO_FAULT_FOP, 160 VN_IO_FAULT_VOP 161 } kind; 162 struct ucred *cred; 163 int flags; 164 union { 165 struct fop_args_tag { 166 struct file *fp; 167 fo_rdwr_t *doio; 168 } fop_args; 169 struct vop_args_tag { 170 struct vnode *vp; 171 } vop_args; 172 } args; 173 }; 174 175 static int vn_io_fault1(struct vnode *vp, struct uio *uio, 176 struct vn_io_fault_args *args, struct thread *td); 177 178 int 179 vn_open(struct nameidata *ndp, int *flagp, int cmode, struct file *fp) 180 { 181 struct thread *td = ndp->ni_cnd.cn_thread; 182 183 return (vn_open_cred(ndp, flagp, cmode, 0, td->td_ucred, fp)); 184 } 185 186 /* 187 * Common code for vnode open operations via a name lookup. 188 * Lookup the vnode and invoke VOP_CREATE if needed. 189 * Check permissions, and call the VOP_OPEN or VOP_CREATE routine. 190 * 191 * Note that this does NOT free nameidata for the successful case, 192 * due to the NDINIT being done elsewhere. 193 */ 194 int 195 vn_open_cred(struct nameidata *ndp, int *flagp, int cmode, u_int vn_open_flags, 196 struct ucred *cred, struct file *fp) 197 { 198 struct vnode *vp; 199 struct mount *mp; 200 struct thread *td = ndp->ni_cnd.cn_thread; 201 struct vattr vat; 202 struct vattr *vap = &vat; 203 int fmode, error; 204 205 restart: 206 fmode = *flagp; 207 if ((fmode & (O_CREAT | O_EXCL | O_DIRECTORY)) == (O_CREAT | 208 O_EXCL | O_DIRECTORY)) 209 return (EINVAL); 210 else if ((fmode & (O_CREAT | O_DIRECTORY)) == O_CREAT) { 211 ndp->ni_cnd.cn_nameiop = CREATE; 212 /* 213 * Set NOCACHE to avoid flushing the cache when 214 * rolling in many files at once. 215 */ 216 ndp->ni_cnd.cn_flags = ISOPEN | LOCKPARENT | LOCKLEAF | NOCACHE; 217 if ((fmode & O_EXCL) == 0 && (fmode & O_NOFOLLOW) == 0) 218 ndp->ni_cnd.cn_flags |= FOLLOW; 219 if ((fmode & O_BENEATH) != 0) 220 ndp->ni_cnd.cn_flags |= BENEATH; 221 if (!(vn_open_flags & VN_OPEN_NOAUDIT)) 222 ndp->ni_cnd.cn_flags |= AUDITVNODE1; 223 if (vn_open_flags & VN_OPEN_NOCAPCHECK) 224 ndp->ni_cnd.cn_flags |= NOCAPCHECK; 225 if ((vn_open_flags & VN_OPEN_INVFS) == 0) 226 bwillwrite(); 227 if ((error = namei(ndp)) != 0) 228 return (error); 229 if (ndp->ni_vp == NULL) { 230 VATTR_NULL(vap); 231 vap->va_type = VREG; 232 vap->va_mode = cmode; 233 if (fmode & O_EXCL) 234 vap->va_vaflags |= VA_EXCLUSIVE; 235 if (vn_start_write(ndp->ni_dvp, &mp, V_NOWAIT) != 0) { 236 NDFREE(ndp, NDF_ONLY_PNBUF); 237 vput(ndp->ni_dvp); 238 if ((error = vn_start_write(NULL, &mp, 239 V_XSLEEP | PCATCH)) != 0) 240 return (error); 241 goto restart; 242 } 243 if ((vn_open_flags & VN_OPEN_NAMECACHE) != 0) 244 ndp->ni_cnd.cn_flags |= MAKEENTRY; 245 #ifdef MAC 246 error = mac_vnode_check_create(cred, ndp->ni_dvp, 247 &ndp->ni_cnd, vap); 248 if (error == 0) 249 #endif 250 error = VOP_CREATE(ndp->ni_dvp, &ndp->ni_vp, 251 &ndp->ni_cnd, vap); 252 vput(ndp->ni_dvp); 253 vn_finished_write(mp); 254 if (error) { 255 NDFREE(ndp, NDF_ONLY_PNBUF); 256 return (error); 257 } 258 fmode &= ~O_TRUNC; 259 vp = ndp->ni_vp; 260 } else { 261 if (ndp->ni_dvp == ndp->ni_vp) 262 vrele(ndp->ni_dvp); 263 else 264 vput(ndp->ni_dvp); 265 ndp->ni_dvp = NULL; 266 vp = ndp->ni_vp; 267 if (fmode & O_EXCL) { 268 error = EEXIST; 269 goto bad; 270 } 271 if (vp->v_type == VDIR) { 272 error = EISDIR; 273 goto bad; 274 } 275 fmode &= ~O_CREAT; 276 } 277 } else { 278 ndp->ni_cnd.cn_nameiop = LOOKUP; 279 ndp->ni_cnd.cn_flags = ISOPEN | 280 ((fmode & O_NOFOLLOW) ? NOFOLLOW : FOLLOW) | LOCKLEAF; 281 if (!(fmode & FWRITE)) 282 ndp->ni_cnd.cn_flags |= LOCKSHARED; 283 if ((fmode & O_BENEATH) != 0) 284 ndp->ni_cnd.cn_flags |= BENEATH; 285 if (!(vn_open_flags & VN_OPEN_NOAUDIT)) 286 ndp->ni_cnd.cn_flags |= AUDITVNODE1; 287 if (vn_open_flags & VN_OPEN_NOCAPCHECK) 288 ndp->ni_cnd.cn_flags |= NOCAPCHECK; 289 if ((error = namei(ndp)) != 0) 290 return (error); 291 vp = ndp->ni_vp; 292 } 293 error = vn_open_vnode(vp, fmode, cred, td, fp); 294 if (error) 295 goto bad; 296 *flagp = fmode; 297 return (0); 298 bad: 299 NDFREE(ndp, NDF_ONLY_PNBUF); 300 vput(vp); 301 *flagp = fmode; 302 ndp->ni_vp = NULL; 303 return (error); 304 } 305 306 static int 307 vn_open_vnode_advlock(struct vnode *vp, int fmode, struct file *fp) 308 { 309 struct flock lf; 310 int error, lock_flags, type; 311 312 ASSERT_VOP_LOCKED(vp, "vn_open_vnode_advlock"); 313 if ((fmode & (O_EXLOCK | O_SHLOCK)) == 0) 314 return (0); 315 KASSERT(fp != NULL, ("open with flock requires fp")); 316 if (fp->f_type != DTYPE_NONE && fp->f_type != DTYPE_VNODE) 317 return (EOPNOTSUPP); 318 319 lock_flags = VOP_ISLOCKED(vp); 320 VOP_UNLOCK(vp); 321 322 lf.l_whence = SEEK_SET; 323 lf.l_start = 0; 324 lf.l_len = 0; 325 lf.l_type = (fmode & O_EXLOCK) != 0 ? F_WRLCK : F_RDLCK; 326 type = F_FLOCK; 327 if ((fmode & FNONBLOCK) == 0) 328 type |= F_WAIT; 329 error = VOP_ADVLOCK(vp, (caddr_t)fp, F_SETLK, &lf, type); 330 if (error == 0) 331 fp->f_flag |= FHASLOCK; 332 333 vn_lock(vp, lock_flags | LK_RETRY); 334 if (error == 0 && VN_IS_DOOMED(vp)) 335 error = ENOENT; 336 return (error); 337 } 338 339 /* 340 * Common code for vnode open operations once a vnode is located. 341 * Check permissions, and call the VOP_OPEN routine. 342 */ 343 int 344 vn_open_vnode(struct vnode *vp, int fmode, struct ucred *cred, 345 struct thread *td, struct file *fp) 346 { 347 accmode_t accmode; 348 int error; 349 350 if (vp->v_type == VLNK) 351 return (EMLINK); 352 if (vp->v_type == VSOCK) 353 return (EOPNOTSUPP); 354 if (vp->v_type != VDIR && fmode & O_DIRECTORY) 355 return (ENOTDIR); 356 accmode = 0; 357 if (fmode & (FWRITE | O_TRUNC)) { 358 if (vp->v_type == VDIR) 359 return (EISDIR); 360 accmode |= VWRITE; 361 } 362 if (fmode & FREAD) 363 accmode |= VREAD; 364 if (fmode & FEXEC) 365 accmode |= VEXEC; 366 if ((fmode & O_APPEND) && (fmode & FWRITE)) 367 accmode |= VAPPEND; 368 #ifdef MAC 369 if (fmode & O_CREAT) 370 accmode |= VCREAT; 371 if (fmode & O_VERIFY) 372 accmode |= VVERIFY; 373 error = mac_vnode_check_open(cred, vp, accmode); 374 if (error) 375 return (error); 376 377 accmode &= ~(VCREAT | VVERIFY); 378 #endif 379 if ((fmode & O_CREAT) == 0 && accmode != 0) { 380 error = VOP_ACCESS(vp, accmode, cred, td); 381 if (error != 0) 382 return (error); 383 } 384 if (vp->v_type == VFIFO && VOP_ISLOCKED(vp) != LK_EXCLUSIVE) 385 vn_lock(vp, LK_UPGRADE | LK_RETRY); 386 error = VOP_OPEN(vp, fmode, cred, td, fp); 387 if (error != 0) 388 return (error); 389 390 error = vn_open_vnode_advlock(vp, fmode, fp); 391 if (error == 0 && (fmode & FWRITE) != 0) { 392 error = VOP_ADD_WRITECOUNT(vp, 1); 393 if (error == 0) { 394 CTR3(KTR_VFS, "%s: vp %p v_writecount increased to %d", 395 __func__, vp, vp->v_writecount); 396 } 397 } 398 399 /* 400 * Error from advlock or VOP_ADD_WRITECOUNT() still requires 401 * calling VOP_CLOSE() to pair with earlier VOP_OPEN(). 402 * Arrange for that by having fdrop() to use vn_closefile(). 403 */ 404 if (error != 0) { 405 fp->f_flag |= FOPENFAILED; 406 fp->f_vnode = vp; 407 if (fp->f_ops == &badfileops) { 408 fp->f_type = DTYPE_VNODE; 409 fp->f_ops = &vnops; 410 } 411 vref(vp); 412 } 413 414 ASSERT_VOP_LOCKED(vp, "vn_open_vnode"); 415 return (error); 416 417 } 418 419 /* 420 * Check for write permissions on the specified vnode. 421 * Prototype text segments cannot be written. 422 * It is racy. 423 */ 424 int 425 vn_writechk(struct vnode *vp) 426 { 427 428 ASSERT_VOP_LOCKED(vp, "vn_writechk"); 429 /* 430 * If there's shared text associated with 431 * the vnode, try to free it up once. If 432 * we fail, we can't allow writing. 433 */ 434 if (VOP_IS_TEXT(vp)) 435 return (ETXTBSY); 436 437 return (0); 438 } 439 440 /* 441 * Vnode close call 442 */ 443 static int 444 vn_close1(struct vnode *vp, int flags, struct ucred *file_cred, 445 struct thread *td, bool keep_ref) 446 { 447 struct mount *mp; 448 int error, lock_flags; 449 450 if (vp->v_type != VFIFO && (flags & FWRITE) == 0 && 451 MNT_EXTENDED_SHARED(vp->v_mount)) 452 lock_flags = LK_SHARED; 453 else 454 lock_flags = LK_EXCLUSIVE; 455 456 vn_start_write(vp, &mp, V_WAIT); 457 vn_lock(vp, lock_flags | LK_RETRY); 458 AUDIT_ARG_VNODE1(vp); 459 if ((flags & (FWRITE | FOPENFAILED)) == FWRITE) { 460 VOP_ADD_WRITECOUNT_CHECKED(vp, -1); 461 CTR3(KTR_VFS, "%s: vp %p v_writecount decreased to %d", 462 __func__, vp, vp->v_writecount); 463 } 464 error = VOP_CLOSE(vp, flags, file_cred, td); 465 if (keep_ref) 466 VOP_UNLOCK(vp); 467 else 468 vput(vp); 469 vn_finished_write(mp); 470 return (error); 471 } 472 473 int 474 vn_close(struct vnode *vp, int flags, struct ucred *file_cred, 475 struct thread *td) 476 { 477 478 return (vn_close1(vp, flags, file_cred, td, false)); 479 } 480 481 /* 482 * Heuristic to detect sequential operation. 483 */ 484 static int 485 sequential_heuristic(struct uio *uio, struct file *fp) 486 { 487 488 ASSERT_VOP_LOCKED(fp->f_vnode, __func__); 489 if (fp->f_flag & FRDAHEAD) 490 return (fp->f_seqcount << IO_SEQSHIFT); 491 492 /* 493 * Offset 0 is handled specially. open() sets f_seqcount to 1 so 494 * that the first I/O is normally considered to be slightly 495 * sequential. Seeking to offset 0 doesn't change sequentiality 496 * unless previous seeks have reduced f_seqcount to 0, in which 497 * case offset 0 is not special. 498 */ 499 if ((uio->uio_offset == 0 && fp->f_seqcount > 0) || 500 uio->uio_offset == fp->f_nextoff) { 501 /* 502 * f_seqcount is in units of fixed-size blocks so that it 503 * depends mainly on the amount of sequential I/O and not 504 * much on the number of sequential I/O's. The fixed size 505 * of 16384 is hard-coded here since it is (not quite) just 506 * a magic size that works well here. This size is more 507 * closely related to the best I/O size for real disks than 508 * to any block size used by software. 509 */ 510 if (uio->uio_resid >= IO_SEQMAX * 16384) 511 fp->f_seqcount = IO_SEQMAX; 512 else { 513 fp->f_seqcount += howmany(uio->uio_resid, 16384); 514 if (fp->f_seqcount > IO_SEQMAX) 515 fp->f_seqcount = IO_SEQMAX; 516 } 517 return (fp->f_seqcount << IO_SEQSHIFT); 518 } 519 520 /* Not sequential. Quickly draw-down sequentiality. */ 521 if (fp->f_seqcount > 1) 522 fp->f_seqcount = 1; 523 else 524 fp->f_seqcount = 0; 525 return (0); 526 } 527 528 /* 529 * Package up an I/O request on a vnode into a uio and do it. 530 */ 531 int 532 vn_rdwr(enum uio_rw rw, struct vnode *vp, void *base, int len, off_t offset, 533 enum uio_seg segflg, int ioflg, struct ucred *active_cred, 534 struct ucred *file_cred, ssize_t *aresid, struct thread *td) 535 { 536 struct uio auio; 537 struct iovec aiov; 538 struct mount *mp; 539 struct ucred *cred; 540 void *rl_cookie; 541 struct vn_io_fault_args args; 542 int error, lock_flags; 543 544 if (offset < 0 && vp->v_type != VCHR) 545 return (EINVAL); 546 auio.uio_iov = &aiov; 547 auio.uio_iovcnt = 1; 548 aiov.iov_base = base; 549 aiov.iov_len = len; 550 auio.uio_resid = len; 551 auio.uio_offset = offset; 552 auio.uio_segflg = segflg; 553 auio.uio_rw = rw; 554 auio.uio_td = td; 555 error = 0; 556 557 if ((ioflg & IO_NODELOCKED) == 0) { 558 if ((ioflg & IO_RANGELOCKED) == 0) { 559 if (rw == UIO_READ) { 560 rl_cookie = vn_rangelock_rlock(vp, offset, 561 offset + len); 562 } else { 563 rl_cookie = vn_rangelock_wlock(vp, offset, 564 offset + len); 565 } 566 } else 567 rl_cookie = NULL; 568 mp = NULL; 569 if (rw == UIO_WRITE) { 570 if (vp->v_type != VCHR && 571 (error = vn_start_write(vp, &mp, V_WAIT | PCATCH)) 572 != 0) 573 goto out; 574 if (MNT_SHARED_WRITES(mp) || 575 ((mp == NULL) && MNT_SHARED_WRITES(vp->v_mount))) 576 lock_flags = LK_SHARED; 577 else 578 lock_flags = LK_EXCLUSIVE; 579 } else 580 lock_flags = LK_SHARED; 581 vn_lock(vp, lock_flags | LK_RETRY); 582 } else 583 rl_cookie = NULL; 584 585 ASSERT_VOP_LOCKED(vp, "IO_NODELOCKED with no vp lock held"); 586 #ifdef MAC 587 if ((ioflg & IO_NOMACCHECK) == 0) { 588 if (rw == UIO_READ) 589 error = mac_vnode_check_read(active_cred, file_cred, 590 vp); 591 else 592 error = mac_vnode_check_write(active_cred, file_cred, 593 vp); 594 } 595 #endif 596 if (error == 0) { 597 if (file_cred != NULL) 598 cred = file_cred; 599 else 600 cred = active_cred; 601 if (do_vn_io_fault(vp, &auio)) { 602 args.kind = VN_IO_FAULT_VOP; 603 args.cred = cred; 604 args.flags = ioflg; 605 args.args.vop_args.vp = vp; 606 error = vn_io_fault1(vp, &auio, &args, td); 607 } else if (rw == UIO_READ) { 608 error = VOP_READ(vp, &auio, ioflg, cred); 609 } else /* if (rw == UIO_WRITE) */ { 610 error = VOP_WRITE(vp, &auio, ioflg, cred); 611 } 612 } 613 if (aresid) 614 *aresid = auio.uio_resid; 615 else 616 if (auio.uio_resid && error == 0) 617 error = EIO; 618 if ((ioflg & IO_NODELOCKED) == 0) { 619 VOP_UNLOCK(vp); 620 if (mp != NULL) 621 vn_finished_write(mp); 622 } 623 out: 624 if (rl_cookie != NULL) 625 vn_rangelock_unlock(vp, rl_cookie); 626 return (error); 627 } 628 629 /* 630 * Package up an I/O request on a vnode into a uio and do it. The I/O 631 * request is split up into smaller chunks and we try to avoid saturating 632 * the buffer cache while potentially holding a vnode locked, so we 633 * check bwillwrite() before calling vn_rdwr(). We also call kern_yield() 634 * to give other processes a chance to lock the vnode (either other processes 635 * core'ing the same binary, or unrelated processes scanning the directory). 636 */ 637 int 638 vn_rdwr_inchunks(enum uio_rw rw, struct vnode *vp, void *base, size_t len, 639 off_t offset, enum uio_seg segflg, int ioflg, struct ucred *active_cred, 640 struct ucred *file_cred, size_t *aresid, struct thread *td) 641 { 642 int error = 0; 643 ssize_t iaresid; 644 645 do { 646 int chunk; 647 648 /* 649 * Force `offset' to a multiple of MAXBSIZE except possibly 650 * for the first chunk, so that filesystems only need to 651 * write full blocks except possibly for the first and last 652 * chunks. 653 */ 654 chunk = MAXBSIZE - (uoff_t)offset % MAXBSIZE; 655 656 if (chunk > len) 657 chunk = len; 658 if (rw != UIO_READ && vp->v_type == VREG) 659 bwillwrite(); 660 iaresid = 0; 661 error = vn_rdwr(rw, vp, base, chunk, offset, segflg, 662 ioflg, active_cred, file_cred, &iaresid, td); 663 len -= chunk; /* aresid calc already includes length */ 664 if (error) 665 break; 666 offset += chunk; 667 base = (char *)base + chunk; 668 kern_yield(PRI_USER); 669 } while (len); 670 if (aresid) 671 *aresid = len + iaresid; 672 return (error); 673 } 674 675 #if OFF_MAX <= LONG_MAX 676 off_t 677 foffset_lock(struct file *fp, int flags) 678 { 679 volatile short *flagsp; 680 off_t res; 681 short state; 682 683 KASSERT((flags & FOF_OFFSET) == 0, ("FOF_OFFSET passed")); 684 685 if ((flags & FOF_NOLOCK) != 0) 686 return (atomic_load_long(&fp->f_offset)); 687 688 /* 689 * According to McKusick the vn lock was protecting f_offset here. 690 * It is now protected by the FOFFSET_LOCKED flag. 691 */ 692 flagsp = &fp->f_vnread_flags; 693 if (atomic_cmpset_acq_16(flagsp, 0, FOFFSET_LOCKED)) 694 return (atomic_load_long(&fp->f_offset)); 695 696 sleepq_lock(&fp->f_vnread_flags); 697 state = atomic_load_16(flagsp); 698 for (;;) { 699 if ((state & FOFFSET_LOCKED) == 0) { 700 if (!atomic_fcmpset_acq_16(flagsp, &state, 701 FOFFSET_LOCKED)) 702 continue; 703 break; 704 } 705 if ((state & FOFFSET_LOCK_WAITING) == 0) { 706 if (!atomic_fcmpset_acq_16(flagsp, &state, 707 state | FOFFSET_LOCK_WAITING)) 708 continue; 709 } 710 DROP_GIANT(); 711 sleepq_add(&fp->f_vnread_flags, NULL, "vofflock", 0, 0); 712 sleepq_wait(&fp->f_vnread_flags, PUSER -1); 713 PICKUP_GIANT(); 714 sleepq_lock(&fp->f_vnread_flags); 715 state = atomic_load_16(flagsp); 716 } 717 res = atomic_load_long(&fp->f_offset); 718 sleepq_release(&fp->f_vnread_flags); 719 return (res); 720 } 721 722 void 723 foffset_unlock(struct file *fp, off_t val, int flags) 724 { 725 volatile short *flagsp; 726 short state; 727 728 KASSERT((flags & FOF_OFFSET) == 0, ("FOF_OFFSET passed")); 729 730 if ((flags & FOF_NOUPDATE) == 0) 731 atomic_store_long(&fp->f_offset, val); 732 if ((flags & FOF_NEXTOFF) != 0) 733 fp->f_nextoff = val; 734 735 if ((flags & FOF_NOLOCK) != 0) 736 return; 737 738 flagsp = &fp->f_vnread_flags; 739 state = atomic_load_16(flagsp); 740 if ((state & FOFFSET_LOCK_WAITING) == 0 && 741 atomic_cmpset_rel_16(flagsp, state, 0)) 742 return; 743 744 sleepq_lock(&fp->f_vnread_flags); 745 MPASS((fp->f_vnread_flags & FOFFSET_LOCKED) != 0); 746 MPASS((fp->f_vnread_flags & FOFFSET_LOCK_WAITING) != 0); 747 fp->f_vnread_flags = 0; 748 sleepq_broadcast(&fp->f_vnread_flags, SLEEPQ_SLEEP, 0, 0); 749 sleepq_release(&fp->f_vnread_flags); 750 } 751 #else 752 off_t 753 foffset_lock(struct file *fp, int flags) 754 { 755 struct mtx *mtxp; 756 off_t res; 757 758 KASSERT((flags & FOF_OFFSET) == 0, ("FOF_OFFSET passed")); 759 760 mtxp = mtx_pool_find(mtxpool_sleep, fp); 761 mtx_lock(mtxp); 762 if ((flags & FOF_NOLOCK) == 0) { 763 while (fp->f_vnread_flags & FOFFSET_LOCKED) { 764 fp->f_vnread_flags |= FOFFSET_LOCK_WAITING; 765 msleep(&fp->f_vnread_flags, mtxp, PUSER -1, 766 "vofflock", 0); 767 } 768 fp->f_vnread_flags |= FOFFSET_LOCKED; 769 } 770 res = fp->f_offset; 771 mtx_unlock(mtxp); 772 return (res); 773 } 774 775 void 776 foffset_unlock(struct file *fp, off_t val, int flags) 777 { 778 struct mtx *mtxp; 779 780 KASSERT((flags & FOF_OFFSET) == 0, ("FOF_OFFSET passed")); 781 782 mtxp = mtx_pool_find(mtxpool_sleep, fp); 783 mtx_lock(mtxp); 784 if ((flags & FOF_NOUPDATE) == 0) 785 fp->f_offset = val; 786 if ((flags & FOF_NEXTOFF) != 0) 787 fp->f_nextoff = val; 788 if ((flags & FOF_NOLOCK) == 0) { 789 KASSERT((fp->f_vnread_flags & FOFFSET_LOCKED) != 0, 790 ("Lost FOFFSET_LOCKED")); 791 if (fp->f_vnread_flags & FOFFSET_LOCK_WAITING) 792 wakeup(&fp->f_vnread_flags); 793 fp->f_vnread_flags = 0; 794 } 795 mtx_unlock(mtxp); 796 } 797 #endif 798 799 void 800 foffset_lock_uio(struct file *fp, struct uio *uio, int flags) 801 { 802 803 if ((flags & FOF_OFFSET) == 0) 804 uio->uio_offset = foffset_lock(fp, flags); 805 } 806 807 void 808 foffset_unlock_uio(struct file *fp, struct uio *uio, int flags) 809 { 810 811 if ((flags & FOF_OFFSET) == 0) 812 foffset_unlock(fp, uio->uio_offset, flags); 813 } 814 815 static int 816 get_advice(struct file *fp, struct uio *uio) 817 { 818 struct mtx *mtxp; 819 int ret; 820 821 ret = POSIX_FADV_NORMAL; 822 if (fp->f_advice == NULL || fp->f_vnode->v_type != VREG) 823 return (ret); 824 825 mtxp = mtx_pool_find(mtxpool_sleep, fp); 826 mtx_lock(mtxp); 827 if (fp->f_advice != NULL && 828 uio->uio_offset >= fp->f_advice->fa_start && 829 uio->uio_offset + uio->uio_resid <= fp->f_advice->fa_end) 830 ret = fp->f_advice->fa_advice; 831 mtx_unlock(mtxp); 832 return (ret); 833 } 834 835 /* 836 * File table vnode read routine. 837 */ 838 static int 839 vn_read(struct file *fp, struct uio *uio, struct ucred *active_cred, int flags, 840 struct thread *td) 841 { 842 struct vnode *vp; 843 off_t orig_offset; 844 int error, ioflag; 845 int advice; 846 847 KASSERT(uio->uio_td == td, ("uio_td %p is not td %p", 848 uio->uio_td, td)); 849 KASSERT(flags & FOF_OFFSET, ("No FOF_OFFSET")); 850 vp = fp->f_vnode; 851 ioflag = 0; 852 if (fp->f_flag & FNONBLOCK) 853 ioflag |= IO_NDELAY; 854 if (fp->f_flag & O_DIRECT) 855 ioflag |= IO_DIRECT; 856 advice = get_advice(fp, uio); 857 vn_lock(vp, LK_SHARED | LK_RETRY); 858 859 switch (advice) { 860 case POSIX_FADV_NORMAL: 861 case POSIX_FADV_SEQUENTIAL: 862 case POSIX_FADV_NOREUSE: 863 ioflag |= sequential_heuristic(uio, fp); 864 break; 865 case POSIX_FADV_RANDOM: 866 /* Disable read-ahead for random I/O. */ 867 break; 868 } 869 orig_offset = uio->uio_offset; 870 871 #ifdef MAC 872 error = mac_vnode_check_read(active_cred, fp->f_cred, vp); 873 if (error == 0) 874 #endif 875 error = VOP_READ(vp, uio, ioflag, fp->f_cred); 876 fp->f_nextoff = uio->uio_offset; 877 VOP_UNLOCK(vp); 878 if (error == 0 && advice == POSIX_FADV_NOREUSE && 879 orig_offset != uio->uio_offset) 880 /* 881 * Use POSIX_FADV_DONTNEED to flush pages and buffers 882 * for the backing file after a POSIX_FADV_NOREUSE 883 * read(2). 884 */ 885 error = VOP_ADVISE(vp, orig_offset, uio->uio_offset - 1, 886 POSIX_FADV_DONTNEED); 887 return (error); 888 } 889 890 /* 891 * File table vnode write routine. 892 */ 893 static int 894 vn_write(struct file *fp, struct uio *uio, struct ucred *active_cred, int flags, 895 struct thread *td) 896 { 897 struct vnode *vp; 898 struct mount *mp; 899 off_t orig_offset; 900 int error, ioflag, lock_flags; 901 int advice; 902 903 KASSERT(uio->uio_td == td, ("uio_td %p is not td %p", 904 uio->uio_td, td)); 905 KASSERT(flags & FOF_OFFSET, ("No FOF_OFFSET")); 906 vp = fp->f_vnode; 907 if (vp->v_type == VREG) 908 bwillwrite(); 909 ioflag = IO_UNIT; 910 if (vp->v_type == VREG && (fp->f_flag & O_APPEND)) 911 ioflag |= IO_APPEND; 912 if (fp->f_flag & FNONBLOCK) 913 ioflag |= IO_NDELAY; 914 if (fp->f_flag & O_DIRECT) 915 ioflag |= IO_DIRECT; 916 if ((fp->f_flag & O_FSYNC) || 917 (vp->v_mount && (vp->v_mount->mnt_flag & MNT_SYNCHRONOUS))) 918 ioflag |= IO_SYNC; 919 mp = NULL; 920 if (vp->v_type != VCHR && 921 (error = vn_start_write(vp, &mp, V_WAIT | PCATCH)) != 0) 922 goto unlock; 923 924 advice = get_advice(fp, uio); 925 926 if (MNT_SHARED_WRITES(mp) || 927 (mp == NULL && MNT_SHARED_WRITES(vp->v_mount))) { 928 lock_flags = LK_SHARED; 929 } else { 930 lock_flags = LK_EXCLUSIVE; 931 } 932 933 vn_lock(vp, lock_flags | LK_RETRY); 934 switch (advice) { 935 case POSIX_FADV_NORMAL: 936 case POSIX_FADV_SEQUENTIAL: 937 case POSIX_FADV_NOREUSE: 938 ioflag |= sequential_heuristic(uio, fp); 939 break; 940 case POSIX_FADV_RANDOM: 941 /* XXX: Is this correct? */ 942 break; 943 } 944 orig_offset = uio->uio_offset; 945 946 #ifdef MAC 947 error = mac_vnode_check_write(active_cred, fp->f_cred, vp); 948 if (error == 0) 949 #endif 950 error = VOP_WRITE(vp, uio, ioflag, fp->f_cred); 951 fp->f_nextoff = uio->uio_offset; 952 VOP_UNLOCK(vp); 953 if (vp->v_type != VCHR) 954 vn_finished_write(mp); 955 if (error == 0 && advice == POSIX_FADV_NOREUSE && 956 orig_offset != uio->uio_offset) 957 /* 958 * Use POSIX_FADV_DONTNEED to flush pages and buffers 959 * for the backing file after a POSIX_FADV_NOREUSE 960 * write(2). 961 */ 962 error = VOP_ADVISE(vp, orig_offset, uio->uio_offset - 1, 963 POSIX_FADV_DONTNEED); 964 unlock: 965 return (error); 966 } 967 968 /* 969 * The vn_io_fault() is a wrapper around vn_read() and vn_write() to 970 * prevent the following deadlock: 971 * 972 * Assume that the thread A reads from the vnode vp1 into userspace 973 * buffer buf1 backed by the pages of vnode vp2. If a page in buf1 is 974 * currently not resident, then system ends up with the call chain 975 * vn_read() -> VOP_READ(vp1) -> uiomove() -> [Page Fault] -> 976 * vm_fault(buf1) -> vnode_pager_getpages(vp2) -> VOP_GETPAGES(vp2) 977 * which establishes lock order vp1->vn_lock, then vp2->vn_lock. 978 * If, at the same time, thread B reads from vnode vp2 into buffer buf2 979 * backed by the pages of vnode vp1, and some page in buf2 is not 980 * resident, we get a reversed order vp2->vn_lock, then vp1->vn_lock. 981 * 982 * To prevent the lock order reversal and deadlock, vn_io_fault() does 983 * not allow page faults to happen during VOP_READ() or VOP_WRITE(). 984 * Instead, it first tries to do the whole range i/o with pagefaults 985 * disabled. If all pages in the i/o buffer are resident and mapped, 986 * VOP will succeed (ignoring the genuine filesystem errors). 987 * Otherwise, we get back EFAULT, and vn_io_fault() falls back to do 988 * i/o in chunks, with all pages in the chunk prefaulted and held 989 * using vm_fault_quick_hold_pages(). 990 * 991 * Filesystems using this deadlock avoidance scheme should use the 992 * array of the held pages from uio, saved in the curthread->td_ma, 993 * instead of doing uiomove(). A helper function 994 * vn_io_fault_uiomove() converts uiomove request into 995 * uiomove_fromphys() over td_ma array. 996 * 997 * Since vnode locks do not cover the whole i/o anymore, rangelocks 998 * make the current i/o request atomic with respect to other i/os and 999 * truncations. 1000 */ 1001 1002 /* 1003 * Decode vn_io_fault_args and perform the corresponding i/o. 1004 */ 1005 static int 1006 vn_io_fault_doio(struct vn_io_fault_args *args, struct uio *uio, 1007 struct thread *td) 1008 { 1009 int error, save; 1010 1011 error = 0; 1012 save = vm_fault_disable_pagefaults(); 1013 switch (args->kind) { 1014 case VN_IO_FAULT_FOP: 1015 error = (args->args.fop_args.doio)(args->args.fop_args.fp, 1016 uio, args->cred, args->flags, td); 1017 break; 1018 case VN_IO_FAULT_VOP: 1019 if (uio->uio_rw == UIO_READ) { 1020 error = VOP_READ(args->args.vop_args.vp, uio, 1021 args->flags, args->cred); 1022 } else if (uio->uio_rw == UIO_WRITE) { 1023 error = VOP_WRITE(args->args.vop_args.vp, uio, 1024 args->flags, args->cred); 1025 } 1026 break; 1027 default: 1028 panic("vn_io_fault_doio: unknown kind of io %d %d", 1029 args->kind, uio->uio_rw); 1030 } 1031 vm_fault_enable_pagefaults(save); 1032 return (error); 1033 } 1034 1035 static int 1036 vn_io_fault_touch(char *base, const struct uio *uio) 1037 { 1038 int r; 1039 1040 r = fubyte(base); 1041 if (r == -1 || (uio->uio_rw == UIO_READ && subyte(base, r) == -1)) 1042 return (EFAULT); 1043 return (0); 1044 } 1045 1046 static int 1047 vn_io_fault_prefault_user(const struct uio *uio) 1048 { 1049 char *base; 1050 const struct iovec *iov; 1051 size_t len; 1052 ssize_t resid; 1053 int error, i; 1054 1055 KASSERT(uio->uio_segflg == UIO_USERSPACE, 1056 ("vn_io_fault_prefault userspace")); 1057 1058 error = i = 0; 1059 iov = uio->uio_iov; 1060 resid = uio->uio_resid; 1061 base = iov->iov_base; 1062 len = iov->iov_len; 1063 while (resid > 0) { 1064 error = vn_io_fault_touch(base, uio); 1065 if (error != 0) 1066 break; 1067 if (len < PAGE_SIZE) { 1068 if (len != 0) { 1069 error = vn_io_fault_touch(base + len - 1, uio); 1070 if (error != 0) 1071 break; 1072 resid -= len; 1073 } 1074 if (++i >= uio->uio_iovcnt) 1075 break; 1076 iov = uio->uio_iov + i; 1077 base = iov->iov_base; 1078 len = iov->iov_len; 1079 } else { 1080 len -= PAGE_SIZE; 1081 base += PAGE_SIZE; 1082 resid -= PAGE_SIZE; 1083 } 1084 } 1085 return (error); 1086 } 1087 1088 /* 1089 * Common code for vn_io_fault(), agnostic to the kind of i/o request. 1090 * Uses vn_io_fault_doio() to make the call to an actual i/o function. 1091 * Used from vn_rdwr() and vn_io_fault(), which encode the i/o request 1092 * into args and call vn_io_fault1() to handle faults during the user 1093 * mode buffer accesses. 1094 */ 1095 static int 1096 vn_io_fault1(struct vnode *vp, struct uio *uio, struct vn_io_fault_args *args, 1097 struct thread *td) 1098 { 1099 vm_page_t ma[io_hold_cnt + 2]; 1100 struct uio *uio_clone, short_uio; 1101 struct iovec short_iovec[1]; 1102 vm_page_t *prev_td_ma; 1103 vm_prot_t prot; 1104 vm_offset_t addr, end; 1105 size_t len, resid; 1106 ssize_t adv; 1107 int error, cnt, saveheld, prev_td_ma_cnt; 1108 1109 if (vn_io_fault_prefault) { 1110 error = vn_io_fault_prefault_user(uio); 1111 if (error != 0) 1112 return (error); /* Or ignore ? */ 1113 } 1114 1115 prot = uio->uio_rw == UIO_READ ? VM_PROT_WRITE : VM_PROT_READ; 1116 1117 /* 1118 * The UFS follows IO_UNIT directive and replays back both 1119 * uio_offset and uio_resid if an error is encountered during the 1120 * operation. But, since the iovec may be already advanced, 1121 * uio is still in an inconsistent state. 1122 * 1123 * Cache a copy of the original uio, which is advanced to the redo 1124 * point using UIO_NOCOPY below. 1125 */ 1126 uio_clone = cloneuio(uio); 1127 resid = uio->uio_resid; 1128 1129 short_uio.uio_segflg = UIO_USERSPACE; 1130 short_uio.uio_rw = uio->uio_rw; 1131 short_uio.uio_td = uio->uio_td; 1132 1133 error = vn_io_fault_doio(args, uio, td); 1134 if (error != EFAULT) 1135 goto out; 1136 1137 atomic_add_long(&vn_io_faults_cnt, 1); 1138 uio_clone->uio_segflg = UIO_NOCOPY; 1139 uiomove(NULL, resid - uio->uio_resid, uio_clone); 1140 uio_clone->uio_segflg = uio->uio_segflg; 1141 1142 saveheld = curthread_pflags_set(TDP_UIOHELD); 1143 prev_td_ma = td->td_ma; 1144 prev_td_ma_cnt = td->td_ma_cnt; 1145 1146 while (uio_clone->uio_resid != 0) { 1147 len = uio_clone->uio_iov->iov_len; 1148 if (len == 0) { 1149 KASSERT(uio_clone->uio_iovcnt >= 1, 1150 ("iovcnt underflow")); 1151 uio_clone->uio_iov++; 1152 uio_clone->uio_iovcnt--; 1153 continue; 1154 } 1155 if (len > io_hold_cnt * PAGE_SIZE) 1156 len = io_hold_cnt * PAGE_SIZE; 1157 addr = (uintptr_t)uio_clone->uio_iov->iov_base; 1158 end = round_page(addr + len); 1159 if (end < addr) { 1160 error = EFAULT; 1161 break; 1162 } 1163 cnt = atop(end - trunc_page(addr)); 1164 /* 1165 * A perfectly misaligned address and length could cause 1166 * both the start and the end of the chunk to use partial 1167 * page. +2 accounts for such a situation. 1168 */ 1169 cnt = vm_fault_quick_hold_pages(&td->td_proc->p_vmspace->vm_map, 1170 addr, len, prot, ma, io_hold_cnt + 2); 1171 if (cnt == -1) { 1172 error = EFAULT; 1173 break; 1174 } 1175 short_uio.uio_iov = &short_iovec[0]; 1176 short_iovec[0].iov_base = (void *)addr; 1177 short_uio.uio_iovcnt = 1; 1178 short_uio.uio_resid = short_iovec[0].iov_len = len; 1179 short_uio.uio_offset = uio_clone->uio_offset; 1180 td->td_ma = ma; 1181 td->td_ma_cnt = cnt; 1182 1183 error = vn_io_fault_doio(args, &short_uio, td); 1184 vm_page_unhold_pages(ma, cnt); 1185 adv = len - short_uio.uio_resid; 1186 1187 uio_clone->uio_iov->iov_base = 1188 (char *)uio_clone->uio_iov->iov_base + adv; 1189 uio_clone->uio_iov->iov_len -= adv; 1190 uio_clone->uio_resid -= adv; 1191 uio_clone->uio_offset += adv; 1192 1193 uio->uio_resid -= adv; 1194 uio->uio_offset += adv; 1195 1196 if (error != 0 || adv == 0) 1197 break; 1198 } 1199 td->td_ma = prev_td_ma; 1200 td->td_ma_cnt = prev_td_ma_cnt; 1201 curthread_pflags_restore(saveheld); 1202 out: 1203 free(uio_clone, M_IOV); 1204 return (error); 1205 } 1206 1207 static int 1208 vn_io_fault(struct file *fp, struct uio *uio, struct ucred *active_cred, 1209 int flags, struct thread *td) 1210 { 1211 fo_rdwr_t *doio; 1212 struct vnode *vp; 1213 void *rl_cookie; 1214 struct vn_io_fault_args args; 1215 int error; 1216 1217 doio = uio->uio_rw == UIO_READ ? vn_read : vn_write; 1218 vp = fp->f_vnode; 1219 foffset_lock_uio(fp, uio, flags); 1220 if (do_vn_io_fault(vp, uio)) { 1221 args.kind = VN_IO_FAULT_FOP; 1222 args.args.fop_args.fp = fp; 1223 args.args.fop_args.doio = doio; 1224 args.cred = active_cred; 1225 args.flags = flags | FOF_OFFSET; 1226 if (uio->uio_rw == UIO_READ) { 1227 rl_cookie = vn_rangelock_rlock(vp, uio->uio_offset, 1228 uio->uio_offset + uio->uio_resid); 1229 } else if ((fp->f_flag & O_APPEND) != 0 || 1230 (flags & FOF_OFFSET) == 0) { 1231 /* For appenders, punt and lock the whole range. */ 1232 rl_cookie = vn_rangelock_wlock(vp, 0, OFF_MAX); 1233 } else { 1234 rl_cookie = vn_rangelock_wlock(vp, uio->uio_offset, 1235 uio->uio_offset + uio->uio_resid); 1236 } 1237 error = vn_io_fault1(vp, uio, &args, td); 1238 vn_rangelock_unlock(vp, rl_cookie); 1239 } else { 1240 error = doio(fp, uio, active_cred, flags | FOF_OFFSET, td); 1241 } 1242 foffset_unlock_uio(fp, uio, flags); 1243 return (error); 1244 } 1245 1246 /* 1247 * Helper function to perform the requested uiomove operation using 1248 * the held pages for io->uio_iov[0].iov_base buffer instead of 1249 * copyin/copyout. Access to the pages with uiomove_fromphys() 1250 * instead of iov_base prevents page faults that could occur due to 1251 * pmap_collect() invalidating the mapping created by 1252 * vm_fault_quick_hold_pages(), or pageout daemon, page laundry or 1253 * object cleanup revoking the write access from page mappings. 1254 * 1255 * Filesystems specified MNTK_NO_IOPF shall use vn_io_fault_uiomove() 1256 * instead of plain uiomove(). 1257 */ 1258 int 1259 vn_io_fault_uiomove(char *data, int xfersize, struct uio *uio) 1260 { 1261 struct uio transp_uio; 1262 struct iovec transp_iov[1]; 1263 struct thread *td; 1264 size_t adv; 1265 int error, pgadv; 1266 1267 td = curthread; 1268 if ((td->td_pflags & TDP_UIOHELD) == 0 || 1269 uio->uio_segflg != UIO_USERSPACE) 1270 return (uiomove(data, xfersize, uio)); 1271 1272 KASSERT(uio->uio_iovcnt == 1, ("uio_iovcnt %d", uio->uio_iovcnt)); 1273 transp_iov[0].iov_base = data; 1274 transp_uio.uio_iov = &transp_iov[0]; 1275 transp_uio.uio_iovcnt = 1; 1276 if (xfersize > uio->uio_resid) 1277 xfersize = uio->uio_resid; 1278 transp_uio.uio_resid = transp_iov[0].iov_len = xfersize; 1279 transp_uio.uio_offset = 0; 1280 transp_uio.uio_segflg = UIO_SYSSPACE; 1281 /* 1282 * Since transp_iov points to data, and td_ma page array 1283 * corresponds to original uio->uio_iov, we need to invert the 1284 * direction of the i/o operation as passed to 1285 * uiomove_fromphys(). 1286 */ 1287 switch (uio->uio_rw) { 1288 case UIO_WRITE: 1289 transp_uio.uio_rw = UIO_READ; 1290 break; 1291 case UIO_READ: 1292 transp_uio.uio_rw = UIO_WRITE; 1293 break; 1294 } 1295 transp_uio.uio_td = uio->uio_td; 1296 error = uiomove_fromphys(td->td_ma, 1297 ((vm_offset_t)uio->uio_iov->iov_base) & PAGE_MASK, 1298 xfersize, &transp_uio); 1299 adv = xfersize - transp_uio.uio_resid; 1300 pgadv = 1301 (((vm_offset_t)uio->uio_iov->iov_base + adv) >> PAGE_SHIFT) - 1302 (((vm_offset_t)uio->uio_iov->iov_base) >> PAGE_SHIFT); 1303 td->td_ma += pgadv; 1304 KASSERT(td->td_ma_cnt >= pgadv, ("consumed pages %d %d", td->td_ma_cnt, 1305 pgadv)); 1306 td->td_ma_cnt -= pgadv; 1307 uio->uio_iov->iov_base = (char *)uio->uio_iov->iov_base + adv; 1308 uio->uio_iov->iov_len -= adv; 1309 uio->uio_resid -= adv; 1310 uio->uio_offset += adv; 1311 return (error); 1312 } 1313 1314 int 1315 vn_io_fault_pgmove(vm_page_t ma[], vm_offset_t offset, int xfersize, 1316 struct uio *uio) 1317 { 1318 struct thread *td; 1319 vm_offset_t iov_base; 1320 int cnt, pgadv; 1321 1322 td = curthread; 1323 if ((td->td_pflags & TDP_UIOHELD) == 0 || 1324 uio->uio_segflg != UIO_USERSPACE) 1325 return (uiomove_fromphys(ma, offset, xfersize, uio)); 1326 1327 KASSERT(uio->uio_iovcnt == 1, ("uio_iovcnt %d", uio->uio_iovcnt)); 1328 cnt = xfersize > uio->uio_resid ? uio->uio_resid : xfersize; 1329 iov_base = (vm_offset_t)uio->uio_iov->iov_base; 1330 switch (uio->uio_rw) { 1331 case UIO_WRITE: 1332 pmap_copy_pages(td->td_ma, iov_base & PAGE_MASK, ma, 1333 offset, cnt); 1334 break; 1335 case UIO_READ: 1336 pmap_copy_pages(ma, offset, td->td_ma, iov_base & PAGE_MASK, 1337 cnt); 1338 break; 1339 } 1340 pgadv = ((iov_base + cnt) >> PAGE_SHIFT) - (iov_base >> PAGE_SHIFT); 1341 td->td_ma += pgadv; 1342 KASSERT(td->td_ma_cnt >= pgadv, ("consumed pages %d %d", td->td_ma_cnt, 1343 pgadv)); 1344 td->td_ma_cnt -= pgadv; 1345 uio->uio_iov->iov_base = (char *)(iov_base + cnt); 1346 uio->uio_iov->iov_len -= cnt; 1347 uio->uio_resid -= cnt; 1348 uio->uio_offset += cnt; 1349 return (0); 1350 } 1351 1352 /* 1353 * File table truncate routine. 1354 */ 1355 static int 1356 vn_truncate(struct file *fp, off_t length, struct ucred *active_cred, 1357 struct thread *td) 1358 { 1359 struct mount *mp; 1360 struct vnode *vp; 1361 void *rl_cookie; 1362 int error; 1363 1364 vp = fp->f_vnode; 1365 1366 /* 1367 * Lock the whole range for truncation. Otherwise split i/o 1368 * might happen partly before and partly after the truncation. 1369 */ 1370 rl_cookie = vn_rangelock_wlock(vp, 0, OFF_MAX); 1371 error = vn_start_write(vp, &mp, V_WAIT | PCATCH); 1372 if (error) 1373 goto out1; 1374 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 1375 AUDIT_ARG_VNODE1(vp); 1376 if (vp->v_type == VDIR) { 1377 error = EISDIR; 1378 goto out; 1379 } 1380 #ifdef MAC 1381 error = mac_vnode_check_write(active_cred, fp->f_cred, vp); 1382 if (error) 1383 goto out; 1384 #endif 1385 error = vn_truncate_locked(vp, length, (fp->f_flag & O_FSYNC) != 0, 1386 fp->f_cred); 1387 out: 1388 VOP_UNLOCK(vp); 1389 vn_finished_write(mp); 1390 out1: 1391 vn_rangelock_unlock(vp, rl_cookie); 1392 return (error); 1393 } 1394 1395 /* 1396 * Truncate a file that is already locked. 1397 */ 1398 int 1399 vn_truncate_locked(struct vnode *vp, off_t length, bool sync, 1400 struct ucred *cred) 1401 { 1402 struct vattr vattr; 1403 int error; 1404 1405 error = VOP_ADD_WRITECOUNT(vp, 1); 1406 if (error == 0) { 1407 VATTR_NULL(&vattr); 1408 vattr.va_size = length; 1409 if (sync) 1410 vattr.va_vaflags |= VA_SYNC; 1411 error = VOP_SETATTR(vp, &vattr, cred); 1412 VOP_ADD_WRITECOUNT_CHECKED(vp, -1); 1413 } 1414 return (error); 1415 } 1416 1417 /* 1418 * File table vnode stat routine. 1419 */ 1420 static int 1421 vn_statfile(struct file *fp, struct stat *sb, struct ucred *active_cred, 1422 struct thread *td) 1423 { 1424 struct vnode *vp = fp->f_vnode; 1425 int error; 1426 1427 vn_lock(vp, LK_SHARED | LK_RETRY); 1428 error = vn_stat(vp, sb, active_cred, fp->f_cred, td); 1429 VOP_UNLOCK(vp); 1430 1431 return (error); 1432 } 1433 1434 /* 1435 * Stat a vnode; implementation for the stat syscall 1436 */ 1437 int 1438 vn_stat(struct vnode *vp, struct stat *sb, struct ucred *active_cred, 1439 struct ucred *file_cred, struct thread *td) 1440 { 1441 struct vattr vattr; 1442 struct vattr *vap; 1443 int error; 1444 u_short mode; 1445 1446 AUDIT_ARG_VNODE1(vp); 1447 #ifdef MAC 1448 error = mac_vnode_check_stat(active_cred, file_cred, vp); 1449 if (error) 1450 return (error); 1451 #endif 1452 1453 vap = &vattr; 1454 1455 /* 1456 * Initialize defaults for new and unusual fields, so that file 1457 * systems which don't support these fields don't need to know 1458 * about them. 1459 */ 1460 vap->va_birthtime.tv_sec = -1; 1461 vap->va_birthtime.tv_nsec = 0; 1462 vap->va_fsid = VNOVAL; 1463 vap->va_rdev = NODEV; 1464 1465 error = VOP_GETATTR(vp, vap, active_cred); 1466 if (error) 1467 return (error); 1468 1469 /* 1470 * Zero the spare stat fields 1471 */ 1472 bzero(sb, sizeof *sb); 1473 1474 /* 1475 * Copy from vattr table 1476 */ 1477 if (vap->va_fsid != VNOVAL) 1478 sb->st_dev = vap->va_fsid; 1479 else 1480 sb->st_dev = vp->v_mount->mnt_stat.f_fsid.val[0]; 1481 sb->st_ino = vap->va_fileid; 1482 mode = vap->va_mode; 1483 switch (vap->va_type) { 1484 case VREG: 1485 mode |= S_IFREG; 1486 break; 1487 case VDIR: 1488 mode |= S_IFDIR; 1489 break; 1490 case VBLK: 1491 mode |= S_IFBLK; 1492 break; 1493 case VCHR: 1494 mode |= S_IFCHR; 1495 break; 1496 case VLNK: 1497 mode |= S_IFLNK; 1498 break; 1499 case VSOCK: 1500 mode |= S_IFSOCK; 1501 break; 1502 case VFIFO: 1503 mode |= S_IFIFO; 1504 break; 1505 default: 1506 return (EBADF); 1507 } 1508 sb->st_mode = mode; 1509 sb->st_nlink = vap->va_nlink; 1510 sb->st_uid = vap->va_uid; 1511 sb->st_gid = vap->va_gid; 1512 sb->st_rdev = vap->va_rdev; 1513 if (vap->va_size > OFF_MAX) 1514 return (EOVERFLOW); 1515 sb->st_size = vap->va_size; 1516 sb->st_atim.tv_sec = vap->va_atime.tv_sec; 1517 sb->st_atim.tv_nsec = vap->va_atime.tv_nsec; 1518 sb->st_mtim.tv_sec = vap->va_mtime.tv_sec; 1519 sb->st_mtim.tv_nsec = vap->va_mtime.tv_nsec; 1520 sb->st_ctim.tv_sec = vap->va_ctime.tv_sec; 1521 sb->st_ctim.tv_nsec = vap->va_ctime.tv_nsec; 1522 sb->st_birthtim.tv_sec = vap->va_birthtime.tv_sec; 1523 sb->st_birthtim.tv_nsec = vap->va_birthtime.tv_nsec; 1524 1525 /* 1526 * According to www.opengroup.org, the meaning of st_blksize is 1527 * "a filesystem-specific preferred I/O block size for this 1528 * object. In some filesystem types, this may vary from file 1529 * to file" 1530 * Use miminum/default of PAGE_SIZE (e.g. for VCHR). 1531 */ 1532 1533 sb->st_blksize = max(PAGE_SIZE, vap->va_blocksize); 1534 1535 sb->st_flags = vap->va_flags; 1536 if (priv_check_cred_vfs_generation(td->td_ucred)) 1537 sb->st_gen = 0; 1538 else 1539 sb->st_gen = vap->va_gen; 1540 1541 sb->st_blocks = vap->va_bytes / S_BLKSIZE; 1542 return (0); 1543 } 1544 1545 /* 1546 * File table vnode ioctl routine. 1547 */ 1548 static int 1549 vn_ioctl(struct file *fp, u_long com, void *data, struct ucred *active_cred, 1550 struct thread *td) 1551 { 1552 struct vattr vattr; 1553 struct vnode *vp; 1554 struct fiobmap2_arg *bmarg; 1555 int error; 1556 1557 vp = fp->f_vnode; 1558 switch (vp->v_type) { 1559 case VDIR: 1560 case VREG: 1561 switch (com) { 1562 case FIONREAD: 1563 vn_lock(vp, LK_SHARED | LK_RETRY); 1564 error = VOP_GETATTR(vp, &vattr, active_cred); 1565 VOP_UNLOCK(vp); 1566 if (error == 0) 1567 *(int *)data = vattr.va_size - fp->f_offset; 1568 return (error); 1569 case FIOBMAP2: 1570 bmarg = (struct fiobmap2_arg *)data; 1571 vn_lock(vp, LK_SHARED | LK_RETRY); 1572 #ifdef MAC 1573 error = mac_vnode_check_read(active_cred, fp->f_cred, 1574 vp); 1575 if (error == 0) 1576 #endif 1577 error = VOP_BMAP(vp, bmarg->bn, NULL, 1578 &bmarg->bn, &bmarg->runp, &bmarg->runb); 1579 VOP_UNLOCK(vp); 1580 return (error); 1581 case FIONBIO: 1582 case FIOASYNC: 1583 return (0); 1584 default: 1585 return (VOP_IOCTL(vp, com, data, fp->f_flag, 1586 active_cred, td)); 1587 } 1588 break; 1589 case VCHR: 1590 return (VOP_IOCTL(vp, com, data, fp->f_flag, 1591 active_cred, td)); 1592 default: 1593 return (ENOTTY); 1594 } 1595 } 1596 1597 /* 1598 * File table vnode poll routine. 1599 */ 1600 static int 1601 vn_poll(struct file *fp, int events, struct ucred *active_cred, 1602 struct thread *td) 1603 { 1604 struct vnode *vp; 1605 int error; 1606 1607 vp = fp->f_vnode; 1608 #ifdef MAC 1609 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 1610 AUDIT_ARG_VNODE1(vp); 1611 error = mac_vnode_check_poll(active_cred, fp->f_cred, vp); 1612 VOP_UNLOCK(vp); 1613 if (!error) 1614 #endif 1615 1616 error = VOP_POLL(vp, events, fp->f_cred, td); 1617 return (error); 1618 } 1619 1620 /* 1621 * Acquire the requested lock and then check for validity. LK_RETRY 1622 * permits vn_lock to return doomed vnodes. 1623 */ 1624 static int __noinline 1625 _vn_lock_fallback(struct vnode *vp, int flags, const char *file, int line, 1626 int error) 1627 { 1628 1629 KASSERT((flags & LK_RETRY) == 0 || error == 0, 1630 ("vn_lock: error %d incompatible with flags %#x", error, flags)); 1631 1632 if (error == 0) 1633 VNASSERT(VN_IS_DOOMED(vp), vp, ("vnode not doomed")); 1634 1635 if ((flags & LK_RETRY) == 0) { 1636 if (error == 0) { 1637 VOP_UNLOCK(vp); 1638 error = ENOENT; 1639 } 1640 return (error); 1641 } 1642 1643 /* 1644 * LK_RETRY case. 1645 * 1646 * Nothing to do if we got the lock. 1647 */ 1648 if (error == 0) 1649 return (0); 1650 1651 /* 1652 * Interlock was dropped by the call in _vn_lock. 1653 */ 1654 flags &= ~LK_INTERLOCK; 1655 do { 1656 error = VOP_LOCK1(vp, flags, file, line); 1657 } while (error != 0); 1658 return (0); 1659 } 1660 1661 int 1662 _vn_lock(struct vnode *vp, int flags, const char *file, int line) 1663 { 1664 int error; 1665 1666 VNASSERT((flags & LK_TYPE_MASK) != 0, vp, 1667 ("vn_lock: no locktype (%d passed)", flags)); 1668 VNPASS(vp->v_holdcnt > 0, vp); 1669 error = VOP_LOCK1(vp, flags, file, line); 1670 if (__predict_false(error != 0 || VN_IS_DOOMED(vp))) 1671 return (_vn_lock_fallback(vp, flags, file, line, error)); 1672 return (0); 1673 } 1674 1675 /* 1676 * File table vnode close routine. 1677 */ 1678 static int 1679 vn_closefile(struct file *fp, struct thread *td) 1680 { 1681 struct vnode *vp; 1682 struct flock lf; 1683 int error; 1684 bool ref; 1685 1686 vp = fp->f_vnode; 1687 fp->f_ops = &badfileops; 1688 ref= (fp->f_flag & FHASLOCK) != 0 && fp->f_type == DTYPE_VNODE; 1689 1690 error = vn_close1(vp, fp->f_flag, fp->f_cred, td, ref); 1691 1692 if (__predict_false(ref)) { 1693 lf.l_whence = SEEK_SET; 1694 lf.l_start = 0; 1695 lf.l_len = 0; 1696 lf.l_type = F_UNLCK; 1697 (void) VOP_ADVLOCK(vp, fp, F_UNLCK, &lf, F_FLOCK); 1698 vrele(vp); 1699 } 1700 return (error); 1701 } 1702 1703 /* 1704 * Preparing to start a filesystem write operation. If the operation is 1705 * permitted, then we bump the count of operations in progress and 1706 * proceed. If a suspend request is in progress, we wait until the 1707 * suspension is over, and then proceed. 1708 */ 1709 static int 1710 vn_start_write_refed(struct mount *mp, int flags, bool mplocked) 1711 { 1712 int error, mflags; 1713 1714 if (__predict_true(!mplocked) && (flags & V_XSLEEP) == 0 && 1715 vfs_op_thread_enter(mp)) { 1716 MPASS((mp->mnt_kern_flag & MNTK_SUSPEND) == 0); 1717 vfs_mp_count_add_pcpu(mp, writeopcount, 1); 1718 vfs_op_thread_exit(mp); 1719 return (0); 1720 } 1721 1722 if (mplocked) 1723 mtx_assert(MNT_MTX(mp), MA_OWNED); 1724 else 1725 MNT_ILOCK(mp); 1726 1727 error = 0; 1728 1729 /* 1730 * Check on status of suspension. 1731 */ 1732 if ((curthread->td_pflags & TDP_IGNSUSP) == 0 || 1733 mp->mnt_susp_owner != curthread) { 1734 mflags = ((mp->mnt_vfc->vfc_flags & VFCF_SBDRY) != 0 ? 1735 (flags & PCATCH) : 0) | (PUSER - 1); 1736 while ((mp->mnt_kern_flag & MNTK_SUSPEND) != 0) { 1737 if (flags & V_NOWAIT) { 1738 error = EWOULDBLOCK; 1739 goto unlock; 1740 } 1741 error = msleep(&mp->mnt_flag, MNT_MTX(mp), mflags, 1742 "suspfs", 0); 1743 if (error) 1744 goto unlock; 1745 } 1746 } 1747 if (flags & V_XSLEEP) 1748 goto unlock; 1749 mp->mnt_writeopcount++; 1750 unlock: 1751 if (error != 0 || (flags & V_XSLEEP) != 0) 1752 MNT_REL(mp); 1753 MNT_IUNLOCK(mp); 1754 return (error); 1755 } 1756 1757 int 1758 vn_start_write(struct vnode *vp, struct mount **mpp, int flags) 1759 { 1760 struct mount *mp; 1761 int error; 1762 1763 KASSERT((flags & V_MNTREF) == 0 || (*mpp != NULL && vp == NULL), 1764 ("V_MNTREF requires mp")); 1765 1766 error = 0; 1767 /* 1768 * If a vnode is provided, get and return the mount point that 1769 * to which it will write. 1770 */ 1771 if (vp != NULL) { 1772 if ((error = VOP_GETWRITEMOUNT(vp, mpp)) != 0) { 1773 *mpp = NULL; 1774 if (error != EOPNOTSUPP) 1775 return (error); 1776 return (0); 1777 } 1778 } 1779 if ((mp = *mpp) == NULL) 1780 return (0); 1781 1782 /* 1783 * VOP_GETWRITEMOUNT() returns with the mp refcount held through 1784 * a vfs_ref(). 1785 * As long as a vnode is not provided we need to acquire a 1786 * refcount for the provided mountpoint too, in order to 1787 * emulate a vfs_ref(). 1788 */ 1789 if (vp == NULL && (flags & V_MNTREF) == 0) 1790 vfs_ref(mp); 1791 1792 return (vn_start_write_refed(mp, flags, false)); 1793 } 1794 1795 /* 1796 * Secondary suspension. Used by operations such as vop_inactive 1797 * routines that are needed by the higher level functions. These 1798 * are allowed to proceed until all the higher level functions have 1799 * completed (indicated by mnt_writeopcount dropping to zero). At that 1800 * time, these operations are halted until the suspension is over. 1801 */ 1802 int 1803 vn_start_secondary_write(struct vnode *vp, struct mount **mpp, int flags) 1804 { 1805 struct mount *mp; 1806 int error; 1807 1808 KASSERT((flags & V_MNTREF) == 0 || (*mpp != NULL && vp == NULL), 1809 ("V_MNTREF requires mp")); 1810 1811 retry: 1812 if (vp != NULL) { 1813 if ((error = VOP_GETWRITEMOUNT(vp, mpp)) != 0) { 1814 *mpp = NULL; 1815 if (error != EOPNOTSUPP) 1816 return (error); 1817 return (0); 1818 } 1819 } 1820 /* 1821 * If we are not suspended or have not yet reached suspended 1822 * mode, then let the operation proceed. 1823 */ 1824 if ((mp = *mpp) == NULL) 1825 return (0); 1826 1827 /* 1828 * VOP_GETWRITEMOUNT() returns with the mp refcount held through 1829 * a vfs_ref(). 1830 * As long as a vnode is not provided we need to acquire a 1831 * refcount for the provided mountpoint too, in order to 1832 * emulate a vfs_ref(). 1833 */ 1834 MNT_ILOCK(mp); 1835 if (vp == NULL && (flags & V_MNTREF) == 0) 1836 MNT_REF(mp); 1837 if ((mp->mnt_kern_flag & (MNTK_SUSPENDED | MNTK_SUSPEND2)) == 0) { 1838 mp->mnt_secondary_writes++; 1839 mp->mnt_secondary_accwrites++; 1840 MNT_IUNLOCK(mp); 1841 return (0); 1842 } 1843 if (flags & V_NOWAIT) { 1844 MNT_REL(mp); 1845 MNT_IUNLOCK(mp); 1846 return (EWOULDBLOCK); 1847 } 1848 /* 1849 * Wait for the suspension to finish. 1850 */ 1851 error = msleep(&mp->mnt_flag, MNT_MTX(mp), (PUSER - 1) | PDROP | 1852 ((mp->mnt_vfc->vfc_flags & VFCF_SBDRY) != 0 ? (flags & PCATCH) : 0), 1853 "suspfs", 0); 1854 vfs_rel(mp); 1855 if (error == 0) 1856 goto retry; 1857 return (error); 1858 } 1859 1860 /* 1861 * Filesystem write operation has completed. If we are suspending and this 1862 * operation is the last one, notify the suspender that the suspension is 1863 * now in effect. 1864 */ 1865 void 1866 vn_finished_write(struct mount *mp) 1867 { 1868 int c; 1869 1870 if (mp == NULL) 1871 return; 1872 1873 if (vfs_op_thread_enter(mp)) { 1874 vfs_mp_count_sub_pcpu(mp, writeopcount, 1); 1875 vfs_mp_count_sub_pcpu(mp, ref, 1); 1876 vfs_op_thread_exit(mp); 1877 return; 1878 } 1879 1880 MNT_ILOCK(mp); 1881 vfs_assert_mount_counters(mp); 1882 MNT_REL(mp); 1883 c = --mp->mnt_writeopcount; 1884 if (mp->mnt_vfs_ops == 0) { 1885 MPASS((mp->mnt_kern_flag & MNTK_SUSPEND) == 0); 1886 MNT_IUNLOCK(mp); 1887 return; 1888 } 1889 if (c < 0) 1890 vfs_dump_mount_counters(mp); 1891 if ((mp->mnt_kern_flag & MNTK_SUSPEND) != 0 && c == 0) 1892 wakeup(&mp->mnt_writeopcount); 1893 MNT_IUNLOCK(mp); 1894 } 1895 1896 /* 1897 * Filesystem secondary write operation has completed. If we are 1898 * suspending and this operation is the last one, notify the suspender 1899 * that the suspension is now in effect. 1900 */ 1901 void 1902 vn_finished_secondary_write(struct mount *mp) 1903 { 1904 if (mp == NULL) 1905 return; 1906 MNT_ILOCK(mp); 1907 MNT_REL(mp); 1908 mp->mnt_secondary_writes--; 1909 if (mp->mnt_secondary_writes < 0) 1910 panic("vn_finished_secondary_write: neg cnt"); 1911 if ((mp->mnt_kern_flag & MNTK_SUSPEND) != 0 && 1912 mp->mnt_secondary_writes <= 0) 1913 wakeup(&mp->mnt_secondary_writes); 1914 MNT_IUNLOCK(mp); 1915 } 1916 1917 /* 1918 * Request a filesystem to suspend write operations. 1919 */ 1920 int 1921 vfs_write_suspend(struct mount *mp, int flags) 1922 { 1923 int error; 1924 1925 vfs_op_enter(mp); 1926 1927 MNT_ILOCK(mp); 1928 vfs_assert_mount_counters(mp); 1929 if (mp->mnt_susp_owner == curthread) { 1930 vfs_op_exit_locked(mp); 1931 MNT_IUNLOCK(mp); 1932 return (EALREADY); 1933 } 1934 while (mp->mnt_kern_flag & MNTK_SUSPEND) 1935 msleep(&mp->mnt_flag, MNT_MTX(mp), PUSER - 1, "wsuspfs", 0); 1936 1937 /* 1938 * Unmount holds a write reference on the mount point. If we 1939 * own busy reference and drain for writers, we deadlock with 1940 * the reference draining in the unmount path. Callers of 1941 * vfs_write_suspend() must specify VS_SKIP_UNMOUNT if 1942 * vfs_busy() reference is owned and caller is not in the 1943 * unmount context. 1944 */ 1945 if ((flags & VS_SKIP_UNMOUNT) != 0 && 1946 (mp->mnt_kern_flag & MNTK_UNMOUNT) != 0) { 1947 vfs_op_exit_locked(mp); 1948 MNT_IUNLOCK(mp); 1949 return (EBUSY); 1950 } 1951 1952 mp->mnt_kern_flag |= MNTK_SUSPEND; 1953 mp->mnt_susp_owner = curthread; 1954 if (mp->mnt_writeopcount > 0) 1955 (void) msleep(&mp->mnt_writeopcount, 1956 MNT_MTX(mp), (PUSER - 1)|PDROP, "suspwt", 0); 1957 else 1958 MNT_IUNLOCK(mp); 1959 if ((error = VFS_SYNC(mp, MNT_SUSPEND)) != 0) { 1960 vfs_write_resume(mp, 0); 1961 /* vfs_write_resume does vfs_op_exit() for us */ 1962 } 1963 return (error); 1964 } 1965 1966 /* 1967 * Request a filesystem to resume write operations. 1968 */ 1969 void 1970 vfs_write_resume(struct mount *mp, int flags) 1971 { 1972 1973 MNT_ILOCK(mp); 1974 if ((mp->mnt_kern_flag & MNTK_SUSPEND) != 0) { 1975 KASSERT(mp->mnt_susp_owner == curthread, ("mnt_susp_owner")); 1976 mp->mnt_kern_flag &= ~(MNTK_SUSPEND | MNTK_SUSPEND2 | 1977 MNTK_SUSPENDED); 1978 mp->mnt_susp_owner = NULL; 1979 wakeup(&mp->mnt_writeopcount); 1980 wakeup(&mp->mnt_flag); 1981 curthread->td_pflags &= ~TDP_IGNSUSP; 1982 if ((flags & VR_START_WRITE) != 0) { 1983 MNT_REF(mp); 1984 mp->mnt_writeopcount++; 1985 } 1986 MNT_IUNLOCK(mp); 1987 if ((flags & VR_NO_SUSPCLR) == 0) 1988 VFS_SUSP_CLEAN(mp); 1989 vfs_op_exit(mp); 1990 } else if ((flags & VR_START_WRITE) != 0) { 1991 MNT_REF(mp); 1992 vn_start_write_refed(mp, 0, true); 1993 } else { 1994 MNT_IUNLOCK(mp); 1995 } 1996 } 1997 1998 /* 1999 * Helper loop around vfs_write_suspend() for filesystem unmount VFS 2000 * methods. 2001 */ 2002 int 2003 vfs_write_suspend_umnt(struct mount *mp) 2004 { 2005 int error; 2006 2007 KASSERT((curthread->td_pflags & TDP_IGNSUSP) == 0, 2008 ("vfs_write_suspend_umnt: recursed")); 2009 2010 /* dounmount() already called vn_start_write(). */ 2011 for (;;) { 2012 vn_finished_write(mp); 2013 error = vfs_write_suspend(mp, 0); 2014 if (error != 0) { 2015 vn_start_write(NULL, &mp, V_WAIT); 2016 return (error); 2017 } 2018 MNT_ILOCK(mp); 2019 if ((mp->mnt_kern_flag & MNTK_SUSPENDED) != 0) 2020 break; 2021 MNT_IUNLOCK(mp); 2022 vn_start_write(NULL, &mp, V_WAIT); 2023 } 2024 mp->mnt_kern_flag &= ~(MNTK_SUSPENDED | MNTK_SUSPEND2); 2025 wakeup(&mp->mnt_flag); 2026 MNT_IUNLOCK(mp); 2027 curthread->td_pflags |= TDP_IGNSUSP; 2028 return (0); 2029 } 2030 2031 /* 2032 * Implement kqueues for files by translating it to vnode operation. 2033 */ 2034 static int 2035 vn_kqfilter(struct file *fp, struct knote *kn) 2036 { 2037 2038 return (VOP_KQFILTER(fp->f_vnode, kn)); 2039 } 2040 2041 /* 2042 * Simplified in-kernel wrapper calls for extended attribute access. 2043 * Both calls pass in a NULL credential, authorizing as "kernel" access. 2044 * Set IO_NODELOCKED in ioflg if the vnode is already locked. 2045 */ 2046 int 2047 vn_extattr_get(struct vnode *vp, int ioflg, int attrnamespace, 2048 const char *attrname, int *buflen, char *buf, struct thread *td) 2049 { 2050 struct uio auio; 2051 struct iovec iov; 2052 int error; 2053 2054 iov.iov_len = *buflen; 2055 iov.iov_base = buf; 2056 2057 auio.uio_iov = &iov; 2058 auio.uio_iovcnt = 1; 2059 auio.uio_rw = UIO_READ; 2060 auio.uio_segflg = UIO_SYSSPACE; 2061 auio.uio_td = td; 2062 auio.uio_offset = 0; 2063 auio.uio_resid = *buflen; 2064 2065 if ((ioflg & IO_NODELOCKED) == 0) 2066 vn_lock(vp, LK_SHARED | LK_RETRY); 2067 2068 ASSERT_VOP_LOCKED(vp, "IO_NODELOCKED with no vp lock held"); 2069 2070 /* authorize attribute retrieval as kernel */ 2071 error = VOP_GETEXTATTR(vp, attrnamespace, attrname, &auio, NULL, NULL, 2072 td); 2073 2074 if ((ioflg & IO_NODELOCKED) == 0) 2075 VOP_UNLOCK(vp); 2076 2077 if (error == 0) { 2078 *buflen = *buflen - auio.uio_resid; 2079 } 2080 2081 return (error); 2082 } 2083 2084 /* 2085 * XXX failure mode if partially written? 2086 */ 2087 int 2088 vn_extattr_set(struct vnode *vp, int ioflg, int attrnamespace, 2089 const char *attrname, int buflen, char *buf, struct thread *td) 2090 { 2091 struct uio auio; 2092 struct iovec iov; 2093 struct mount *mp; 2094 int error; 2095 2096 iov.iov_len = buflen; 2097 iov.iov_base = buf; 2098 2099 auio.uio_iov = &iov; 2100 auio.uio_iovcnt = 1; 2101 auio.uio_rw = UIO_WRITE; 2102 auio.uio_segflg = UIO_SYSSPACE; 2103 auio.uio_td = td; 2104 auio.uio_offset = 0; 2105 auio.uio_resid = buflen; 2106 2107 if ((ioflg & IO_NODELOCKED) == 0) { 2108 if ((error = vn_start_write(vp, &mp, V_WAIT)) != 0) 2109 return (error); 2110 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 2111 } 2112 2113 ASSERT_VOP_LOCKED(vp, "IO_NODELOCKED with no vp lock held"); 2114 2115 /* authorize attribute setting as kernel */ 2116 error = VOP_SETEXTATTR(vp, attrnamespace, attrname, &auio, NULL, td); 2117 2118 if ((ioflg & IO_NODELOCKED) == 0) { 2119 vn_finished_write(mp); 2120 VOP_UNLOCK(vp); 2121 } 2122 2123 return (error); 2124 } 2125 2126 int 2127 vn_extattr_rm(struct vnode *vp, int ioflg, int attrnamespace, 2128 const char *attrname, struct thread *td) 2129 { 2130 struct mount *mp; 2131 int error; 2132 2133 if ((ioflg & IO_NODELOCKED) == 0) { 2134 if ((error = vn_start_write(vp, &mp, V_WAIT)) != 0) 2135 return (error); 2136 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 2137 } 2138 2139 ASSERT_VOP_LOCKED(vp, "IO_NODELOCKED with no vp lock held"); 2140 2141 /* authorize attribute removal as kernel */ 2142 error = VOP_DELETEEXTATTR(vp, attrnamespace, attrname, NULL, td); 2143 if (error == EOPNOTSUPP) 2144 error = VOP_SETEXTATTR(vp, attrnamespace, attrname, NULL, 2145 NULL, td); 2146 2147 if ((ioflg & IO_NODELOCKED) == 0) { 2148 vn_finished_write(mp); 2149 VOP_UNLOCK(vp); 2150 } 2151 2152 return (error); 2153 } 2154 2155 static int 2156 vn_get_ino_alloc_vget(struct mount *mp, void *arg, int lkflags, 2157 struct vnode **rvp) 2158 { 2159 2160 return (VFS_VGET(mp, *(ino_t *)arg, lkflags, rvp)); 2161 } 2162 2163 int 2164 vn_vget_ino(struct vnode *vp, ino_t ino, int lkflags, struct vnode **rvp) 2165 { 2166 2167 return (vn_vget_ino_gen(vp, vn_get_ino_alloc_vget, &ino, 2168 lkflags, rvp)); 2169 } 2170 2171 int 2172 vn_vget_ino_gen(struct vnode *vp, vn_get_ino_t alloc, void *alloc_arg, 2173 int lkflags, struct vnode **rvp) 2174 { 2175 struct mount *mp; 2176 int ltype, error; 2177 2178 ASSERT_VOP_LOCKED(vp, "vn_vget_ino_get"); 2179 mp = vp->v_mount; 2180 ltype = VOP_ISLOCKED(vp); 2181 KASSERT(ltype == LK_EXCLUSIVE || ltype == LK_SHARED, 2182 ("vn_vget_ino: vp not locked")); 2183 error = vfs_busy(mp, MBF_NOWAIT); 2184 if (error != 0) { 2185 vfs_ref(mp); 2186 VOP_UNLOCK(vp); 2187 error = vfs_busy(mp, 0); 2188 vn_lock(vp, ltype | LK_RETRY); 2189 vfs_rel(mp); 2190 if (error != 0) 2191 return (ENOENT); 2192 if (VN_IS_DOOMED(vp)) { 2193 vfs_unbusy(mp); 2194 return (ENOENT); 2195 } 2196 } 2197 VOP_UNLOCK(vp); 2198 error = alloc(mp, alloc_arg, lkflags, rvp); 2199 vfs_unbusy(mp); 2200 if (error != 0 || *rvp != vp) 2201 vn_lock(vp, ltype | LK_RETRY); 2202 if (VN_IS_DOOMED(vp)) { 2203 if (error == 0) { 2204 if (*rvp == vp) 2205 vunref(vp); 2206 else 2207 vput(*rvp); 2208 } 2209 error = ENOENT; 2210 } 2211 return (error); 2212 } 2213 2214 int 2215 vn_rlimit_fsize(const struct vnode *vp, const struct uio *uio, 2216 struct thread *td) 2217 { 2218 2219 if (vp->v_type != VREG || td == NULL) 2220 return (0); 2221 if ((uoff_t)uio->uio_offset + uio->uio_resid > 2222 lim_cur(td, RLIMIT_FSIZE)) { 2223 PROC_LOCK(td->td_proc); 2224 kern_psignal(td->td_proc, SIGXFSZ); 2225 PROC_UNLOCK(td->td_proc); 2226 return (EFBIG); 2227 } 2228 return (0); 2229 } 2230 2231 int 2232 vn_chmod(struct file *fp, mode_t mode, struct ucred *active_cred, 2233 struct thread *td) 2234 { 2235 struct vnode *vp; 2236 2237 vp = fp->f_vnode; 2238 #ifdef AUDIT 2239 vn_lock(vp, LK_SHARED | LK_RETRY); 2240 AUDIT_ARG_VNODE1(vp); 2241 VOP_UNLOCK(vp); 2242 #endif 2243 return (setfmode(td, active_cred, vp, mode)); 2244 } 2245 2246 int 2247 vn_chown(struct file *fp, uid_t uid, gid_t gid, struct ucred *active_cred, 2248 struct thread *td) 2249 { 2250 struct vnode *vp; 2251 2252 vp = fp->f_vnode; 2253 #ifdef AUDIT 2254 vn_lock(vp, LK_SHARED | LK_RETRY); 2255 AUDIT_ARG_VNODE1(vp); 2256 VOP_UNLOCK(vp); 2257 #endif 2258 return (setfown(td, active_cred, vp, uid, gid)); 2259 } 2260 2261 void 2262 vn_pages_remove(struct vnode *vp, vm_pindex_t start, vm_pindex_t end) 2263 { 2264 vm_object_t object; 2265 2266 if ((object = vp->v_object) == NULL) 2267 return; 2268 VM_OBJECT_WLOCK(object); 2269 vm_object_page_remove(object, start, end, 0); 2270 VM_OBJECT_WUNLOCK(object); 2271 } 2272 2273 int 2274 vn_bmap_seekhole(struct vnode *vp, u_long cmd, off_t *off, struct ucred *cred) 2275 { 2276 struct vattr va; 2277 daddr_t bn, bnp; 2278 uint64_t bsize; 2279 off_t noff; 2280 int error; 2281 2282 KASSERT(cmd == FIOSEEKHOLE || cmd == FIOSEEKDATA, 2283 ("Wrong command %lu", cmd)); 2284 2285 if (vn_lock(vp, LK_SHARED) != 0) 2286 return (EBADF); 2287 if (vp->v_type != VREG) { 2288 error = ENOTTY; 2289 goto unlock; 2290 } 2291 error = VOP_GETATTR(vp, &va, cred); 2292 if (error != 0) 2293 goto unlock; 2294 noff = *off; 2295 if (noff >= va.va_size) { 2296 error = ENXIO; 2297 goto unlock; 2298 } 2299 bsize = vp->v_mount->mnt_stat.f_iosize; 2300 for (bn = noff / bsize; noff < va.va_size; bn++, noff += bsize - 2301 noff % bsize) { 2302 error = VOP_BMAP(vp, bn, NULL, &bnp, NULL, NULL); 2303 if (error == EOPNOTSUPP) { 2304 error = ENOTTY; 2305 goto unlock; 2306 } 2307 if ((bnp == -1 && cmd == FIOSEEKHOLE) || 2308 (bnp != -1 && cmd == FIOSEEKDATA)) { 2309 noff = bn * bsize; 2310 if (noff < *off) 2311 noff = *off; 2312 goto unlock; 2313 } 2314 } 2315 if (noff > va.va_size) 2316 noff = va.va_size; 2317 /* noff == va.va_size. There is an implicit hole at the end of file. */ 2318 if (cmd == FIOSEEKDATA) 2319 error = ENXIO; 2320 unlock: 2321 VOP_UNLOCK(vp); 2322 if (error == 0) 2323 *off = noff; 2324 return (error); 2325 } 2326 2327 int 2328 vn_seek(struct file *fp, off_t offset, int whence, struct thread *td) 2329 { 2330 struct ucred *cred; 2331 struct vnode *vp; 2332 struct vattr vattr; 2333 off_t foffset, size; 2334 int error, noneg; 2335 2336 cred = td->td_ucred; 2337 vp = fp->f_vnode; 2338 foffset = foffset_lock(fp, 0); 2339 noneg = (vp->v_type != VCHR); 2340 error = 0; 2341 switch (whence) { 2342 case L_INCR: 2343 if (noneg && 2344 (foffset < 0 || 2345 (offset > 0 && foffset > OFF_MAX - offset))) { 2346 error = EOVERFLOW; 2347 break; 2348 } 2349 offset += foffset; 2350 break; 2351 case L_XTND: 2352 vn_lock(vp, LK_SHARED | LK_RETRY); 2353 error = VOP_GETATTR(vp, &vattr, cred); 2354 VOP_UNLOCK(vp); 2355 if (error) 2356 break; 2357 2358 /* 2359 * If the file references a disk device, then fetch 2360 * the media size and use that to determine the ending 2361 * offset. 2362 */ 2363 if (vattr.va_size == 0 && vp->v_type == VCHR && 2364 fo_ioctl(fp, DIOCGMEDIASIZE, &size, cred, td) == 0) 2365 vattr.va_size = size; 2366 if (noneg && 2367 (vattr.va_size > OFF_MAX || 2368 (offset > 0 && vattr.va_size > OFF_MAX - offset))) { 2369 error = EOVERFLOW; 2370 break; 2371 } 2372 offset += vattr.va_size; 2373 break; 2374 case L_SET: 2375 break; 2376 case SEEK_DATA: 2377 error = fo_ioctl(fp, FIOSEEKDATA, &offset, cred, td); 2378 if (error == ENOTTY) 2379 error = EINVAL; 2380 break; 2381 case SEEK_HOLE: 2382 error = fo_ioctl(fp, FIOSEEKHOLE, &offset, cred, td); 2383 if (error == ENOTTY) 2384 error = EINVAL; 2385 break; 2386 default: 2387 error = EINVAL; 2388 } 2389 if (error == 0 && noneg && offset < 0) 2390 error = EINVAL; 2391 if (error != 0) 2392 goto drop; 2393 VFS_KNOTE_UNLOCKED(vp, 0); 2394 td->td_uretoff.tdu_off = offset; 2395 drop: 2396 foffset_unlock(fp, offset, error != 0 ? FOF_NOUPDATE : 0); 2397 return (error); 2398 } 2399 2400 int 2401 vn_utimes_perm(struct vnode *vp, struct vattr *vap, struct ucred *cred, 2402 struct thread *td) 2403 { 2404 int error; 2405 2406 /* 2407 * Grant permission if the caller is the owner of the file, or 2408 * the super-user, or has ACL_WRITE_ATTRIBUTES permission on 2409 * on the file. If the time pointer is null, then write 2410 * permission on the file is also sufficient. 2411 * 2412 * From NFSv4.1, draft 21, 6.2.1.3.1, Discussion of Mask Attributes: 2413 * A user having ACL_WRITE_DATA or ACL_WRITE_ATTRIBUTES 2414 * will be allowed to set the times [..] to the current 2415 * server time. 2416 */ 2417 error = VOP_ACCESSX(vp, VWRITE_ATTRIBUTES, cred, td); 2418 if (error != 0 && (vap->va_vaflags & VA_UTIMES_NULL) != 0) 2419 error = VOP_ACCESS(vp, VWRITE, cred, td); 2420 return (error); 2421 } 2422 2423 int 2424 vn_fill_kinfo(struct file *fp, struct kinfo_file *kif, struct filedesc *fdp) 2425 { 2426 struct vnode *vp; 2427 int error; 2428 2429 if (fp->f_type == DTYPE_FIFO) 2430 kif->kf_type = KF_TYPE_FIFO; 2431 else 2432 kif->kf_type = KF_TYPE_VNODE; 2433 vp = fp->f_vnode; 2434 vref(vp); 2435 FILEDESC_SUNLOCK(fdp); 2436 error = vn_fill_kinfo_vnode(vp, kif); 2437 vrele(vp); 2438 FILEDESC_SLOCK(fdp); 2439 return (error); 2440 } 2441 2442 static inline void 2443 vn_fill_junk(struct kinfo_file *kif) 2444 { 2445 size_t len, olen; 2446 2447 /* 2448 * Simulate vn_fullpath returning changing values for a given 2449 * vp during e.g. coredump. 2450 */ 2451 len = (arc4random() % (sizeof(kif->kf_path) - 2)) + 1; 2452 olen = strlen(kif->kf_path); 2453 if (len < olen) 2454 strcpy(&kif->kf_path[len - 1], "$"); 2455 else 2456 for (; olen < len; olen++) 2457 strcpy(&kif->kf_path[olen], "A"); 2458 } 2459 2460 int 2461 vn_fill_kinfo_vnode(struct vnode *vp, struct kinfo_file *kif) 2462 { 2463 struct vattr va; 2464 char *fullpath, *freepath; 2465 int error; 2466 2467 kif->kf_un.kf_file.kf_file_type = vntype_to_kinfo(vp->v_type); 2468 freepath = NULL; 2469 fullpath = "-"; 2470 error = vn_fullpath(curthread, vp, &fullpath, &freepath); 2471 if (error == 0) { 2472 strlcpy(kif->kf_path, fullpath, sizeof(kif->kf_path)); 2473 } 2474 if (freepath != NULL) 2475 free(freepath, M_TEMP); 2476 2477 KFAIL_POINT_CODE(DEBUG_FP, fill_kinfo_vnode__random_path, 2478 vn_fill_junk(kif); 2479 ); 2480 2481 /* 2482 * Retrieve vnode attributes. 2483 */ 2484 va.va_fsid = VNOVAL; 2485 va.va_rdev = NODEV; 2486 vn_lock(vp, LK_SHARED | LK_RETRY); 2487 error = VOP_GETATTR(vp, &va, curthread->td_ucred); 2488 VOP_UNLOCK(vp); 2489 if (error != 0) 2490 return (error); 2491 if (va.va_fsid != VNOVAL) 2492 kif->kf_un.kf_file.kf_file_fsid = va.va_fsid; 2493 else 2494 kif->kf_un.kf_file.kf_file_fsid = 2495 vp->v_mount->mnt_stat.f_fsid.val[0]; 2496 kif->kf_un.kf_file.kf_file_fsid_freebsd11 = 2497 kif->kf_un.kf_file.kf_file_fsid; /* truncate */ 2498 kif->kf_un.kf_file.kf_file_fileid = va.va_fileid; 2499 kif->kf_un.kf_file.kf_file_mode = MAKEIMODE(va.va_type, va.va_mode); 2500 kif->kf_un.kf_file.kf_file_size = va.va_size; 2501 kif->kf_un.kf_file.kf_file_rdev = va.va_rdev; 2502 kif->kf_un.kf_file.kf_file_rdev_freebsd11 = 2503 kif->kf_un.kf_file.kf_file_rdev; /* truncate */ 2504 return (0); 2505 } 2506 2507 int 2508 vn_mmap(struct file *fp, vm_map_t map, vm_offset_t *addr, vm_size_t size, 2509 vm_prot_t prot, vm_prot_t cap_maxprot, int flags, vm_ooffset_t foff, 2510 struct thread *td) 2511 { 2512 #ifdef HWPMC_HOOKS 2513 struct pmckern_map_in pkm; 2514 #endif 2515 struct mount *mp; 2516 struct vnode *vp; 2517 vm_object_t object; 2518 vm_prot_t maxprot; 2519 boolean_t writecounted; 2520 int error; 2521 2522 #if defined(COMPAT_FREEBSD7) || defined(COMPAT_FREEBSD6) || \ 2523 defined(COMPAT_FREEBSD5) || defined(COMPAT_FREEBSD4) 2524 /* 2525 * POSIX shared-memory objects are defined to have 2526 * kernel persistence, and are not defined to support 2527 * read(2)/write(2) -- or even open(2). Thus, we can 2528 * use MAP_ASYNC to trade on-disk coherence for speed. 2529 * The shm_open(3) library routine turns on the FPOSIXSHM 2530 * flag to request this behavior. 2531 */ 2532 if ((fp->f_flag & FPOSIXSHM) != 0) 2533 flags |= MAP_NOSYNC; 2534 #endif 2535 vp = fp->f_vnode; 2536 2537 /* 2538 * Ensure that file and memory protections are 2539 * compatible. Note that we only worry about 2540 * writability if mapping is shared; in this case, 2541 * current and max prot are dictated by the open file. 2542 * XXX use the vnode instead? Problem is: what 2543 * credentials do we use for determination? What if 2544 * proc does a setuid? 2545 */ 2546 mp = vp->v_mount; 2547 if (mp != NULL && (mp->mnt_flag & MNT_NOEXEC) != 0) { 2548 maxprot = VM_PROT_NONE; 2549 if ((prot & VM_PROT_EXECUTE) != 0) 2550 return (EACCES); 2551 } else 2552 maxprot = VM_PROT_EXECUTE; 2553 if ((fp->f_flag & FREAD) != 0) 2554 maxprot |= VM_PROT_READ; 2555 else if ((prot & VM_PROT_READ) != 0) 2556 return (EACCES); 2557 2558 /* 2559 * If we are sharing potential changes via MAP_SHARED and we 2560 * are trying to get write permission although we opened it 2561 * without asking for it, bail out. 2562 */ 2563 if ((flags & MAP_SHARED) != 0) { 2564 if ((fp->f_flag & FWRITE) != 0) 2565 maxprot |= VM_PROT_WRITE; 2566 else if ((prot & VM_PROT_WRITE) != 0) 2567 return (EACCES); 2568 } else { 2569 maxprot |= VM_PROT_WRITE; 2570 cap_maxprot |= VM_PROT_WRITE; 2571 } 2572 maxprot &= cap_maxprot; 2573 2574 /* 2575 * For regular files and shared memory, POSIX requires that 2576 * the value of foff be a legitimate offset within the data 2577 * object. In particular, negative offsets are invalid. 2578 * Blocking negative offsets and overflows here avoids 2579 * possible wraparound or user-level access into reserved 2580 * ranges of the data object later. In contrast, POSIX does 2581 * not dictate how offsets are used by device drivers, so in 2582 * the case of a device mapping a negative offset is passed 2583 * on. 2584 */ 2585 if ( 2586 #ifdef _LP64 2587 size > OFF_MAX || 2588 #endif 2589 foff < 0 || foff > OFF_MAX - size) 2590 return (EINVAL); 2591 2592 writecounted = FALSE; 2593 error = vm_mmap_vnode(td, size, prot, &maxprot, &flags, vp, 2594 &foff, &object, &writecounted); 2595 if (error != 0) 2596 return (error); 2597 error = vm_mmap_object(map, addr, size, prot, maxprot, flags, object, 2598 foff, writecounted, td); 2599 if (error != 0) { 2600 /* 2601 * If this mapping was accounted for in the vnode's 2602 * writecount, then undo that now. 2603 */ 2604 if (writecounted) 2605 vm_pager_release_writecount(object, 0, size); 2606 vm_object_deallocate(object); 2607 } 2608 #ifdef HWPMC_HOOKS 2609 /* Inform hwpmc(4) if an executable is being mapped. */ 2610 if (PMC_HOOK_INSTALLED(PMC_FN_MMAP)) { 2611 if ((prot & VM_PROT_EXECUTE) != 0 && error == 0) { 2612 pkm.pm_file = vp; 2613 pkm.pm_address = (uintptr_t) *addr; 2614 PMC_CALL_HOOK_UNLOCKED(td, PMC_FN_MMAP, (void *) &pkm); 2615 } 2616 } 2617 #endif 2618 return (error); 2619 } 2620 2621 void 2622 vn_fsid(struct vnode *vp, struct vattr *va) 2623 { 2624 fsid_t *f; 2625 2626 f = &vp->v_mount->mnt_stat.f_fsid; 2627 va->va_fsid = (uint32_t)f->val[1]; 2628 va->va_fsid <<= sizeof(f->val[1]) * NBBY; 2629 va->va_fsid += (uint32_t)f->val[0]; 2630 } 2631 2632 int 2633 vn_fsync_buf(struct vnode *vp, int waitfor) 2634 { 2635 struct buf *bp, *nbp; 2636 struct bufobj *bo; 2637 struct mount *mp; 2638 int error, maxretry; 2639 2640 error = 0; 2641 maxretry = 10000; /* large, arbitrarily chosen */ 2642 mp = NULL; 2643 if (vp->v_type == VCHR) { 2644 VI_LOCK(vp); 2645 mp = vp->v_rdev->si_mountpt; 2646 VI_UNLOCK(vp); 2647 } 2648 bo = &vp->v_bufobj; 2649 BO_LOCK(bo); 2650 loop1: 2651 /* 2652 * MARK/SCAN initialization to avoid infinite loops. 2653 */ 2654 TAILQ_FOREACH(bp, &bo->bo_dirty.bv_hd, b_bobufs) { 2655 bp->b_vflags &= ~BV_SCANNED; 2656 bp->b_error = 0; 2657 } 2658 2659 /* 2660 * Flush all dirty buffers associated with a vnode. 2661 */ 2662 loop2: 2663 TAILQ_FOREACH_SAFE(bp, &bo->bo_dirty.bv_hd, b_bobufs, nbp) { 2664 if ((bp->b_vflags & BV_SCANNED) != 0) 2665 continue; 2666 bp->b_vflags |= BV_SCANNED; 2667 if (BUF_LOCK(bp, LK_EXCLUSIVE | LK_NOWAIT, NULL)) { 2668 if (waitfor != MNT_WAIT) 2669 continue; 2670 if (BUF_LOCK(bp, 2671 LK_EXCLUSIVE | LK_INTERLOCK | LK_SLEEPFAIL, 2672 BO_LOCKPTR(bo)) != 0) { 2673 BO_LOCK(bo); 2674 goto loop1; 2675 } 2676 BO_LOCK(bo); 2677 } 2678 BO_UNLOCK(bo); 2679 KASSERT(bp->b_bufobj == bo, 2680 ("bp %p wrong b_bufobj %p should be %p", 2681 bp, bp->b_bufobj, bo)); 2682 if ((bp->b_flags & B_DELWRI) == 0) 2683 panic("fsync: not dirty"); 2684 if ((vp->v_object != NULL) && (bp->b_flags & B_CLUSTEROK)) { 2685 vfs_bio_awrite(bp); 2686 } else { 2687 bremfree(bp); 2688 bawrite(bp); 2689 } 2690 if (maxretry < 1000) 2691 pause("dirty", hz < 1000 ? 1 : hz / 1000); 2692 BO_LOCK(bo); 2693 goto loop2; 2694 } 2695 2696 /* 2697 * If synchronous the caller expects us to completely resolve all 2698 * dirty buffers in the system. Wait for in-progress I/O to 2699 * complete (which could include background bitmap writes), then 2700 * retry if dirty blocks still exist. 2701 */ 2702 if (waitfor == MNT_WAIT) { 2703 bufobj_wwait(bo, 0, 0); 2704 if (bo->bo_dirty.bv_cnt > 0) { 2705 /* 2706 * If we are unable to write any of these buffers 2707 * then we fail now rather than trying endlessly 2708 * to write them out. 2709 */ 2710 TAILQ_FOREACH(bp, &bo->bo_dirty.bv_hd, b_bobufs) 2711 if ((error = bp->b_error) != 0) 2712 break; 2713 if ((mp != NULL && mp->mnt_secondary_writes > 0) || 2714 (error == 0 && --maxretry >= 0)) 2715 goto loop1; 2716 if (error == 0) 2717 error = EAGAIN; 2718 } 2719 } 2720 BO_UNLOCK(bo); 2721 if (error != 0) 2722 vn_printf(vp, "fsync: giving up on dirty (error = %d) ", error); 2723 2724 return (error); 2725 } 2726 2727 /* 2728 * Copies a byte range from invp to outvp. Calls VOP_COPY_FILE_RANGE() 2729 * or vn_generic_copy_file_range() after rangelocking the byte ranges, 2730 * to do the actual copy. 2731 * vn_generic_copy_file_range() is factored out, so it can be called 2732 * from a VOP_COPY_FILE_RANGE() call as well, but handles vnodes from 2733 * different file systems. 2734 */ 2735 int 2736 vn_copy_file_range(struct vnode *invp, off_t *inoffp, struct vnode *outvp, 2737 off_t *outoffp, size_t *lenp, unsigned int flags, struct ucred *incred, 2738 struct ucred *outcred, struct thread *fsize_td) 2739 { 2740 int error; 2741 size_t len; 2742 uint64_t uvalin, uvalout; 2743 2744 len = *lenp; 2745 *lenp = 0; /* For error returns. */ 2746 error = 0; 2747 2748 /* Do some sanity checks on the arguments. */ 2749 uvalin = *inoffp; 2750 uvalin += len; 2751 uvalout = *outoffp; 2752 uvalout += len; 2753 if (invp->v_type == VDIR || outvp->v_type == VDIR) 2754 error = EISDIR; 2755 else if (*inoffp < 0 || uvalin > INT64_MAX || uvalin < 2756 (uint64_t)*inoffp || *outoffp < 0 || uvalout > INT64_MAX || 2757 uvalout < (uint64_t)*outoffp || invp->v_type != VREG || 2758 outvp->v_type != VREG) 2759 error = EINVAL; 2760 if (error != 0) 2761 goto out; 2762 2763 /* 2764 * If the two vnode are for the same file system, call 2765 * VOP_COPY_FILE_RANGE(), otherwise call vn_generic_copy_file_range() 2766 * which can handle copies across multiple file systems. 2767 */ 2768 *lenp = len; 2769 if (invp->v_mount == outvp->v_mount) 2770 error = VOP_COPY_FILE_RANGE(invp, inoffp, outvp, outoffp, 2771 lenp, flags, incred, outcred, fsize_td); 2772 else 2773 error = vn_generic_copy_file_range(invp, inoffp, outvp, 2774 outoffp, lenp, flags, incred, outcred, fsize_td); 2775 out: 2776 return (error); 2777 } 2778 2779 /* 2780 * Test len bytes of data starting at dat for all bytes == 0. 2781 * Return true if all bytes are zero, false otherwise. 2782 * Expects dat to be well aligned. 2783 */ 2784 static bool 2785 mem_iszero(void *dat, int len) 2786 { 2787 int i; 2788 const u_int *p; 2789 const char *cp; 2790 2791 for (p = dat; len > 0; len -= sizeof(*p), p++) { 2792 if (len >= sizeof(*p)) { 2793 if (*p != 0) 2794 return (false); 2795 } else { 2796 cp = (const char *)p; 2797 for (i = 0; i < len; i++, cp++) 2798 if (*cp != '\0') 2799 return (false); 2800 } 2801 } 2802 return (true); 2803 } 2804 2805 /* 2806 * Look for a hole in the output file and, if found, adjust *outoffp 2807 * and *xferp to skip past the hole. 2808 * *xferp is the entire hole length to be written and xfer2 is how many bytes 2809 * to be written as 0's upon return. 2810 */ 2811 static off_t 2812 vn_skip_hole(struct vnode *outvp, off_t xfer2, off_t *outoffp, off_t *xferp, 2813 off_t *dataoffp, off_t *holeoffp, struct ucred *cred) 2814 { 2815 int error; 2816 off_t delta; 2817 2818 if (*holeoffp == 0 || *holeoffp <= *outoffp) { 2819 *dataoffp = *outoffp; 2820 error = VOP_IOCTL(outvp, FIOSEEKDATA, dataoffp, 0, cred, 2821 curthread); 2822 if (error == 0) { 2823 *holeoffp = *dataoffp; 2824 error = VOP_IOCTL(outvp, FIOSEEKHOLE, holeoffp, 0, cred, 2825 curthread); 2826 } 2827 if (error != 0 || *holeoffp == *dataoffp) { 2828 /* 2829 * Since outvp is unlocked, it may be possible for 2830 * another thread to do a truncate(), lseek(), write() 2831 * creating a hole at startoff between the above 2832 * VOP_IOCTL() calls, if the other thread does not do 2833 * rangelocking. 2834 * If that happens, *holeoffp == *dataoffp and finding 2835 * the hole has failed, so disable vn_skip_hole(). 2836 */ 2837 *holeoffp = -1; /* Disable use of vn_skip_hole(). */ 2838 return (xfer2); 2839 } 2840 KASSERT(*dataoffp >= *outoffp, 2841 ("vn_skip_hole: dataoff=%jd < outoff=%jd", 2842 (intmax_t)*dataoffp, (intmax_t)*outoffp)); 2843 KASSERT(*holeoffp > *dataoffp, 2844 ("vn_skip_hole: holeoff=%jd <= dataoff=%jd", 2845 (intmax_t)*holeoffp, (intmax_t)*dataoffp)); 2846 } 2847 2848 /* 2849 * If there is a hole before the data starts, advance *outoffp and 2850 * *xferp past the hole. 2851 */ 2852 if (*dataoffp > *outoffp) { 2853 delta = *dataoffp - *outoffp; 2854 if (delta >= *xferp) { 2855 /* Entire *xferp is a hole. */ 2856 *outoffp += *xferp; 2857 *xferp = 0; 2858 return (0); 2859 } 2860 *xferp -= delta; 2861 *outoffp += delta; 2862 xfer2 = MIN(xfer2, *xferp); 2863 } 2864 2865 /* 2866 * If a hole starts before the end of this xfer2, reduce this xfer2 so 2867 * that the write ends at the start of the hole. 2868 * *holeoffp should always be greater than *outoffp, but for the 2869 * non-INVARIANTS case, check this to make sure xfer2 remains a sane 2870 * value. 2871 */ 2872 if (*holeoffp > *outoffp && *holeoffp < *outoffp + xfer2) 2873 xfer2 = *holeoffp - *outoffp; 2874 return (xfer2); 2875 } 2876 2877 /* 2878 * Write an xfer sized chunk to outvp in blksize blocks from dat. 2879 * dat is a maximum of blksize in length and can be written repeatedly in 2880 * the chunk. 2881 * If growfile == true, just grow the file via vn_truncate_locked() instead 2882 * of doing actual writes. 2883 * If checkhole == true, a hole is being punched, so skip over any hole 2884 * already in the output file. 2885 */ 2886 static int 2887 vn_write_outvp(struct vnode *outvp, char *dat, off_t outoff, off_t xfer, 2888 u_long blksize, bool growfile, bool checkhole, struct ucred *cred) 2889 { 2890 struct mount *mp; 2891 off_t dataoff, holeoff, xfer2; 2892 int error, lckf; 2893 2894 /* 2895 * Loop around doing writes of blksize until write has been completed. 2896 * Lock/unlock on each loop iteration so that a bwillwrite() can be 2897 * done for each iteration, since the xfer argument can be very 2898 * large if there is a large hole to punch in the output file. 2899 */ 2900 error = 0; 2901 holeoff = 0; 2902 do { 2903 xfer2 = MIN(xfer, blksize); 2904 if (checkhole) { 2905 /* 2906 * Punching a hole. Skip writing if there is 2907 * already a hole in the output file. 2908 */ 2909 xfer2 = vn_skip_hole(outvp, xfer2, &outoff, &xfer, 2910 &dataoff, &holeoff, cred); 2911 if (xfer == 0) 2912 break; 2913 if (holeoff < 0) 2914 checkhole = false; 2915 KASSERT(xfer2 > 0, ("vn_write_outvp: xfer2=%jd", 2916 (intmax_t)xfer2)); 2917 } 2918 bwillwrite(); 2919 mp = NULL; 2920 error = vn_start_write(outvp, &mp, V_WAIT); 2921 if (error == 0) { 2922 if (MNT_SHARED_WRITES(mp)) 2923 lckf = LK_SHARED; 2924 else 2925 lckf = LK_EXCLUSIVE; 2926 error = vn_lock(outvp, lckf); 2927 } 2928 if (error == 0) { 2929 if (growfile) 2930 error = vn_truncate_locked(outvp, outoff + xfer, 2931 false, cred); 2932 else { 2933 error = vn_rdwr(UIO_WRITE, outvp, dat, xfer2, 2934 outoff, UIO_SYSSPACE, IO_NODELOCKED, 2935 curthread->td_ucred, cred, NULL, curthread); 2936 outoff += xfer2; 2937 xfer -= xfer2; 2938 } 2939 VOP_UNLOCK(outvp); 2940 } 2941 if (mp != NULL) 2942 vn_finished_write(mp); 2943 } while (!growfile && xfer > 0 && error == 0); 2944 return (error); 2945 } 2946 2947 /* 2948 * Copy a byte range of one file to another. This function can handle the 2949 * case where invp and outvp are on different file systems. 2950 * It can also be called by a VOP_COPY_FILE_RANGE() to do the work, if there 2951 * is no better file system specific way to do it. 2952 */ 2953 int 2954 vn_generic_copy_file_range(struct vnode *invp, off_t *inoffp, 2955 struct vnode *outvp, off_t *outoffp, size_t *lenp, unsigned int flags, 2956 struct ucred *incred, struct ucred *outcred, struct thread *fsize_td) 2957 { 2958 struct vattr va; 2959 struct mount *mp; 2960 struct uio io; 2961 off_t startoff, endoff, xfer, xfer2; 2962 u_long blksize; 2963 int error; 2964 bool cantseek, readzeros, eof, lastblock; 2965 ssize_t aresid; 2966 size_t copylen, len, savlen; 2967 char *dat; 2968 long holein, holeout; 2969 2970 holein = holeout = 0; 2971 savlen = len = *lenp; 2972 error = 0; 2973 dat = NULL; 2974 2975 error = vn_lock(invp, LK_SHARED); 2976 if (error != 0) 2977 goto out; 2978 if (VOP_PATHCONF(invp, _PC_MIN_HOLE_SIZE, &holein) != 0) 2979 holein = 0; 2980 VOP_UNLOCK(invp); 2981 2982 mp = NULL; 2983 error = vn_start_write(outvp, &mp, V_WAIT); 2984 if (error == 0) 2985 error = vn_lock(outvp, LK_EXCLUSIVE); 2986 if (error == 0) { 2987 /* 2988 * If fsize_td != NULL, do a vn_rlimit_fsize() call, 2989 * now that outvp is locked. 2990 */ 2991 if (fsize_td != NULL) { 2992 io.uio_offset = *outoffp; 2993 io.uio_resid = len; 2994 error = vn_rlimit_fsize(outvp, &io, fsize_td); 2995 if (error != 0) 2996 error = EFBIG; 2997 } 2998 if (VOP_PATHCONF(outvp, _PC_MIN_HOLE_SIZE, &holeout) != 0) 2999 holeout = 0; 3000 /* 3001 * Holes that are past EOF do not need to be written as a block 3002 * of zero bytes. So, truncate the output file as far as 3003 * possible and then use va.va_size to decide if writing 0 3004 * bytes is necessary in the loop below. 3005 */ 3006 if (error == 0) 3007 error = VOP_GETATTR(outvp, &va, outcred); 3008 if (error == 0 && va.va_size > *outoffp && va.va_size <= 3009 *outoffp + len) { 3010 #ifdef MAC 3011 error = mac_vnode_check_write(curthread->td_ucred, 3012 outcred, outvp); 3013 if (error == 0) 3014 #endif 3015 error = vn_truncate_locked(outvp, *outoffp, 3016 false, outcred); 3017 if (error == 0) 3018 va.va_size = *outoffp; 3019 } 3020 VOP_UNLOCK(outvp); 3021 } 3022 if (mp != NULL) 3023 vn_finished_write(mp); 3024 if (error != 0) 3025 goto out; 3026 3027 /* 3028 * Set the blksize to the larger of the hole sizes for invp and outvp. 3029 * If hole sizes aren't available, set the blksize to the larger 3030 * f_iosize of invp and outvp. 3031 * This code expects the hole sizes and f_iosizes to be powers of 2. 3032 * This value is clipped at 4Kbytes and 1Mbyte. 3033 */ 3034 blksize = MAX(holein, holeout); 3035 if (blksize == 0) 3036 blksize = MAX(invp->v_mount->mnt_stat.f_iosize, 3037 outvp->v_mount->mnt_stat.f_iosize); 3038 if (blksize < 4096) 3039 blksize = 4096; 3040 else if (blksize > 1024 * 1024) 3041 blksize = 1024 * 1024; 3042 dat = malloc(blksize, M_TEMP, M_WAITOK); 3043 3044 /* 3045 * If VOP_IOCTL(FIOSEEKHOLE) works for invp, use it and FIOSEEKDATA 3046 * to find holes. Otherwise, just scan the read block for all 0s 3047 * in the inner loop where the data copying is done. 3048 * Note that some file systems such as NFSv3, NFSv4.0 and NFSv4.1 may 3049 * support holes on the server, but do not support FIOSEEKHOLE. 3050 */ 3051 eof = false; 3052 while (len > 0 && error == 0 && !eof) { 3053 endoff = 0; /* To shut up compilers. */ 3054 cantseek = true; 3055 startoff = *inoffp; 3056 copylen = len; 3057 3058 /* 3059 * Find the next data area. If there is just a hole to EOF, 3060 * FIOSEEKDATA should fail and then we drop down into the 3061 * inner loop and create the hole on the outvp file. 3062 * (I do not know if any file system will report a hole to 3063 * EOF via FIOSEEKHOLE, but I am pretty sure FIOSEEKDATA 3064 * will fail for those file systems.) 3065 * 3066 * For input files that don't support FIOSEEKDATA/FIOSEEKHOLE, 3067 * the code just falls through to the inner copy loop. 3068 */ 3069 error = EINVAL; 3070 if (holein > 0) 3071 error = VOP_IOCTL(invp, FIOSEEKDATA, &startoff, 0, 3072 incred, curthread); 3073 if (error == 0) { 3074 endoff = startoff; 3075 error = VOP_IOCTL(invp, FIOSEEKHOLE, &endoff, 0, 3076 incred, curthread); 3077 /* 3078 * Since invp is unlocked, it may be possible for 3079 * another thread to do a truncate(), lseek(), write() 3080 * creating a hole at startoff between the above 3081 * VOP_IOCTL() calls, if the other thread does not do 3082 * rangelocking. 3083 * If that happens, startoff == endoff and finding 3084 * the hole has failed, so set an error. 3085 */ 3086 if (error == 0 && startoff == endoff) 3087 error = EINVAL; /* Any error. Reset to 0. */ 3088 } 3089 if (error == 0) { 3090 if (startoff > *inoffp) { 3091 /* Found hole before data block. */ 3092 xfer = MIN(startoff - *inoffp, len); 3093 if (*outoffp < va.va_size) { 3094 /* Must write 0s to punch hole. */ 3095 xfer2 = MIN(va.va_size - *outoffp, 3096 xfer); 3097 memset(dat, 0, MIN(xfer2, blksize)); 3098 error = vn_write_outvp(outvp, dat, 3099 *outoffp, xfer2, blksize, false, 3100 holeout > 0, outcred); 3101 } 3102 3103 if (error == 0 && *outoffp + xfer > 3104 va.va_size && xfer == len) 3105 /* Grow last block. */ 3106 error = vn_write_outvp(outvp, dat, 3107 *outoffp, xfer, blksize, true, 3108 false, outcred); 3109 if (error == 0) { 3110 *inoffp += xfer; 3111 *outoffp += xfer; 3112 len -= xfer; 3113 } 3114 } 3115 copylen = MIN(len, endoff - startoff); 3116 cantseek = false; 3117 } else { 3118 cantseek = true; 3119 startoff = *inoffp; 3120 copylen = len; 3121 error = 0; 3122 } 3123 3124 xfer = blksize; 3125 if (cantseek) { 3126 /* 3127 * Set first xfer to end at a block boundary, so that 3128 * holes are more likely detected in the loop below via 3129 * the for all bytes 0 method. 3130 */ 3131 xfer -= (*inoffp % blksize); 3132 } 3133 /* Loop copying the data block. */ 3134 while (copylen > 0 && error == 0 && !eof) { 3135 if (copylen < xfer) 3136 xfer = copylen; 3137 error = vn_lock(invp, LK_SHARED); 3138 if (error != 0) 3139 goto out; 3140 error = vn_rdwr(UIO_READ, invp, dat, xfer, 3141 startoff, UIO_SYSSPACE, IO_NODELOCKED, 3142 curthread->td_ucred, incred, &aresid, 3143 curthread); 3144 VOP_UNLOCK(invp); 3145 lastblock = false; 3146 if (error == 0 && aresid > 0) { 3147 /* Stop the copy at EOF on the input file. */ 3148 xfer -= aresid; 3149 eof = true; 3150 lastblock = true; 3151 } 3152 if (error == 0) { 3153 /* 3154 * Skip the write for holes past the initial EOF 3155 * of the output file, unless this is the last 3156 * write of the output file at EOF. 3157 */ 3158 readzeros = cantseek ? mem_iszero(dat, xfer) : 3159 false; 3160 if (xfer == len) 3161 lastblock = true; 3162 if (!cantseek || *outoffp < va.va_size || 3163 lastblock || !readzeros) 3164 error = vn_write_outvp(outvp, dat, 3165 *outoffp, xfer, blksize, 3166 readzeros && lastblock && 3167 *outoffp >= va.va_size, false, 3168 outcred); 3169 if (error == 0) { 3170 *inoffp += xfer; 3171 startoff += xfer; 3172 *outoffp += xfer; 3173 copylen -= xfer; 3174 len -= xfer; 3175 } 3176 } 3177 xfer = blksize; 3178 } 3179 } 3180 out: 3181 *lenp = savlen - len; 3182 free(dat, M_TEMP); 3183 return (error); 3184 } 3185 3186 static int 3187 vn_fallocate(struct file *fp, off_t offset, off_t len, struct thread *td) 3188 { 3189 struct mount *mp; 3190 struct vnode *vp; 3191 off_t olen, ooffset; 3192 int error; 3193 #ifdef AUDIT 3194 int audited_vnode1 = 0; 3195 #endif 3196 3197 vp = fp->f_vnode; 3198 if (vp->v_type != VREG) 3199 return (ENODEV); 3200 3201 /* Allocating blocks may take a long time, so iterate. */ 3202 for (;;) { 3203 olen = len; 3204 ooffset = offset; 3205 3206 bwillwrite(); 3207 mp = NULL; 3208 error = vn_start_write(vp, &mp, V_WAIT | PCATCH); 3209 if (error != 0) 3210 break; 3211 error = vn_lock(vp, LK_EXCLUSIVE); 3212 if (error != 0) { 3213 vn_finished_write(mp); 3214 break; 3215 } 3216 #ifdef AUDIT 3217 if (!audited_vnode1) { 3218 AUDIT_ARG_VNODE1(vp); 3219 audited_vnode1 = 1; 3220 } 3221 #endif 3222 #ifdef MAC 3223 error = mac_vnode_check_write(td->td_ucred, fp->f_cred, vp); 3224 if (error == 0) 3225 #endif 3226 error = VOP_ALLOCATE(vp, &offset, &len); 3227 VOP_UNLOCK(vp); 3228 vn_finished_write(mp); 3229 3230 if (olen + ooffset != offset + len) { 3231 panic("offset + len changed from %jx/%jx to %jx/%jx", 3232 ooffset, olen, offset, len); 3233 } 3234 if (error != 0 || len == 0) 3235 break; 3236 KASSERT(olen > len, ("Iteration did not make progress?")); 3237 maybe_yield(); 3238 } 3239 3240 return (error); 3241 } 3242