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/prng.h> 74 #include <sys/sx.h> 75 #include <sys/sleepqueue.h> 76 #include <sys/sysctl.h> 77 #include <sys/ttycom.h> 78 #include <sys/conf.h> 79 #include <sys/syslog.h> 80 #include <sys/unistd.h> 81 #include <sys/user.h> 82 83 #include <security/audit/audit.h> 84 #include <security/mac/mac_framework.h> 85 86 #include <vm/vm.h> 87 #include <vm/vm_extern.h> 88 #include <vm/pmap.h> 89 #include <vm/vm_map.h> 90 #include <vm/vm_object.h> 91 #include <vm/vm_page.h> 92 #include <vm/vm_pager.h> 93 94 #ifdef HWPMC_HOOKS 95 #include <sys/pmckern.h> 96 #endif 97 98 static fo_rdwr_t vn_read; 99 static fo_rdwr_t vn_write; 100 static fo_rdwr_t vn_io_fault; 101 static fo_truncate_t vn_truncate; 102 static fo_ioctl_t vn_ioctl; 103 static fo_poll_t vn_poll; 104 static fo_kqfilter_t vn_kqfilter; 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 const u_int io_hold_cnt = 16; 129 static int vn_io_fault_enable = 1; 130 SYSCTL_INT(_debug, OID_AUTO, vn_io_fault_enable, CTLFLAG_RWTUN, 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_RWTUN, 134 &vn_io_fault_prefault, 0, "Enable vn_io_fault prefaulting"); 135 static int vn_io_pgcache_read_enable = 1; 136 SYSCTL_INT(_debug, OID_AUTO, vn_io_pgcache_read_enable, CTLFLAG_RWTUN, 137 &vn_io_pgcache_read_enable, 0, 138 "Enable copying from page cache for reads, avoiding fs"); 139 static u_long vn_io_faults_cnt; 140 SYSCTL_ULONG(_debug, OID_AUTO, vn_io_faults, CTLFLAG_RD, 141 &vn_io_faults_cnt, 0, "Count of vn_io_fault lock avoidance triggers"); 142 143 static int vfs_allow_read_dir = 0; 144 SYSCTL_INT(_security_bsd, OID_AUTO, allow_read_dir, CTLFLAG_RW, 145 &vfs_allow_read_dir, 0, 146 "Enable read(2) of directory by root for filesystems that support it"); 147 148 /* 149 * Returns true if vn_io_fault mode of handling the i/o request should 150 * be used. 151 */ 152 static bool 153 do_vn_io_fault(struct vnode *vp, struct uio *uio) 154 { 155 struct mount *mp; 156 157 return (uio->uio_segflg == UIO_USERSPACE && vp->v_type == VREG && 158 (mp = vp->v_mount) != NULL && 159 (mp->mnt_kern_flag & MNTK_NO_IOPF) != 0 && vn_io_fault_enable); 160 } 161 162 /* 163 * Structure used to pass arguments to vn_io_fault1(), to do either 164 * file- or vnode-based I/O calls. 165 */ 166 struct vn_io_fault_args { 167 enum { 168 VN_IO_FAULT_FOP, 169 VN_IO_FAULT_VOP 170 } kind; 171 struct ucred *cred; 172 int flags; 173 union { 174 struct fop_args_tag { 175 struct file *fp; 176 fo_rdwr_t *doio; 177 } fop_args; 178 struct vop_args_tag { 179 struct vnode *vp; 180 } vop_args; 181 } args; 182 }; 183 184 static int vn_io_fault1(struct vnode *vp, struct uio *uio, 185 struct vn_io_fault_args *args, struct thread *td); 186 187 int 188 vn_open(struct nameidata *ndp, int *flagp, int cmode, struct file *fp) 189 { 190 struct thread *td = ndp->ni_cnd.cn_thread; 191 192 return (vn_open_cred(ndp, flagp, cmode, 0, td->td_ucred, fp)); 193 } 194 195 static uint64_t 196 open2nameif(int fmode, u_int vn_open_flags) 197 { 198 uint64_t res; 199 200 res = ISOPEN | LOCKLEAF; 201 if ((fmode & O_RESOLVE_BENEATH) != 0) 202 res |= RBENEATH; 203 if ((vn_open_flags & VN_OPEN_NOAUDIT) == 0) 204 res |= AUDITVNODE1; 205 if ((vn_open_flags & VN_OPEN_NOCAPCHECK) != 0) 206 res |= NOCAPCHECK; 207 return (res); 208 } 209 210 /* 211 * Common code for vnode open operations via a name lookup. 212 * Lookup the vnode and invoke VOP_CREATE if needed. 213 * Check permissions, and call the VOP_OPEN or VOP_CREATE routine. 214 * 215 * Note that this does NOT free nameidata for the successful case, 216 * due to the NDINIT being done elsewhere. 217 */ 218 int 219 vn_open_cred(struct nameidata *ndp, int *flagp, int cmode, u_int vn_open_flags, 220 struct ucred *cred, struct file *fp) 221 { 222 struct vnode *vp; 223 struct mount *mp; 224 struct thread *td = ndp->ni_cnd.cn_thread; 225 struct vattr vat; 226 struct vattr *vap = &vat; 227 int fmode, error; 228 bool first_open; 229 230 restart: 231 first_open = false; 232 fmode = *flagp; 233 if ((fmode & (O_CREAT | O_EXCL | O_DIRECTORY)) == (O_CREAT | 234 O_EXCL | O_DIRECTORY)) 235 return (EINVAL); 236 else if ((fmode & (O_CREAT | O_DIRECTORY)) == O_CREAT) { 237 ndp->ni_cnd.cn_nameiop = CREATE; 238 ndp->ni_cnd.cn_flags = open2nameif(fmode, vn_open_flags); 239 /* 240 * Set NOCACHE to avoid flushing the cache when 241 * rolling in many files at once. 242 * 243 * Set NC_KEEPPOSENTRY to keep positive entries if they already 244 * exist despite NOCACHE. 245 */ 246 ndp->ni_cnd.cn_flags |= LOCKPARENT | NOCACHE | NC_KEEPPOSENTRY; 247 if ((fmode & O_EXCL) == 0 && (fmode & O_NOFOLLOW) == 0) 248 ndp->ni_cnd.cn_flags |= FOLLOW; 249 if ((vn_open_flags & VN_OPEN_INVFS) == 0) 250 bwillwrite(); 251 if ((error = namei(ndp)) != 0) 252 return (error); 253 if (ndp->ni_vp == NULL) { 254 VATTR_NULL(vap); 255 vap->va_type = VREG; 256 vap->va_mode = cmode; 257 if (fmode & O_EXCL) 258 vap->va_vaflags |= VA_EXCLUSIVE; 259 if (vn_start_write(ndp->ni_dvp, &mp, V_NOWAIT) != 0) { 260 NDFREE(ndp, NDF_ONLY_PNBUF); 261 vput(ndp->ni_dvp); 262 if ((error = vn_start_write(NULL, &mp, 263 V_XSLEEP | PCATCH)) != 0) 264 return (error); 265 NDREINIT(ndp); 266 goto restart; 267 } 268 if ((vn_open_flags & VN_OPEN_NAMECACHE) != 0) 269 ndp->ni_cnd.cn_flags |= MAKEENTRY; 270 #ifdef MAC 271 error = mac_vnode_check_create(cred, ndp->ni_dvp, 272 &ndp->ni_cnd, vap); 273 if (error == 0) 274 #endif 275 error = VOP_CREATE(ndp->ni_dvp, &ndp->ni_vp, 276 &ndp->ni_cnd, vap); 277 vp = ndp->ni_vp; 278 if (error == 0 && (fmode & O_EXCL) != 0 && 279 (fmode & (O_EXLOCK | O_SHLOCK)) != 0) { 280 VI_LOCK(vp); 281 vp->v_iflag |= VI_FOPENING; 282 VI_UNLOCK(vp); 283 first_open = true; 284 } 285 VOP_VPUT_PAIR(ndp->ni_dvp, error == 0 ? &vp : NULL, 286 false); 287 vn_finished_write(mp); 288 if (error) { 289 NDFREE(ndp, NDF_ONLY_PNBUF); 290 if (error == ERELOOKUP) { 291 NDREINIT(ndp); 292 goto restart; 293 } 294 return (error); 295 } 296 fmode &= ~O_TRUNC; 297 } else { 298 if (ndp->ni_dvp == ndp->ni_vp) 299 vrele(ndp->ni_dvp); 300 else 301 vput(ndp->ni_dvp); 302 ndp->ni_dvp = NULL; 303 vp = ndp->ni_vp; 304 if (fmode & O_EXCL) { 305 error = EEXIST; 306 goto bad; 307 } 308 if (vp->v_type == VDIR) { 309 error = EISDIR; 310 goto bad; 311 } 312 fmode &= ~O_CREAT; 313 } 314 } else { 315 ndp->ni_cnd.cn_nameiop = LOOKUP; 316 ndp->ni_cnd.cn_flags = open2nameif(fmode, vn_open_flags); 317 ndp->ni_cnd.cn_flags |= (fmode & O_NOFOLLOW) != 0 ? NOFOLLOW : 318 FOLLOW; 319 if ((fmode & FWRITE) == 0) 320 ndp->ni_cnd.cn_flags |= LOCKSHARED; 321 if ((error = namei(ndp)) != 0) 322 return (error); 323 vp = ndp->ni_vp; 324 } 325 error = vn_open_vnode(vp, fmode, cred, td, fp); 326 if (first_open) { 327 VI_LOCK(vp); 328 vp->v_iflag &= ~VI_FOPENING; 329 wakeup(vp); 330 VI_UNLOCK(vp); 331 } 332 if (error) 333 goto bad; 334 *flagp = fmode; 335 return (0); 336 bad: 337 NDFREE(ndp, NDF_ONLY_PNBUF); 338 vput(vp); 339 *flagp = fmode; 340 ndp->ni_vp = NULL; 341 return (error); 342 } 343 344 static int 345 vn_open_vnode_advlock(struct vnode *vp, int fmode, struct file *fp) 346 { 347 struct flock lf; 348 int error, lock_flags, type; 349 350 ASSERT_VOP_LOCKED(vp, "vn_open_vnode_advlock"); 351 if ((fmode & (O_EXLOCK | O_SHLOCK)) == 0) 352 return (0); 353 KASSERT(fp != NULL, ("open with flock requires fp")); 354 if (fp->f_type != DTYPE_NONE && fp->f_type != DTYPE_VNODE) 355 return (EOPNOTSUPP); 356 357 lock_flags = VOP_ISLOCKED(vp); 358 VOP_UNLOCK(vp); 359 360 lf.l_whence = SEEK_SET; 361 lf.l_start = 0; 362 lf.l_len = 0; 363 lf.l_type = (fmode & O_EXLOCK) != 0 ? F_WRLCK : F_RDLCK; 364 type = F_FLOCK; 365 if ((fmode & FNONBLOCK) == 0) 366 type |= F_WAIT; 367 if ((fmode & (O_CREAT | O_EXCL)) == (O_CREAT | O_EXCL)) 368 type |= F_FIRSTOPEN; 369 error = VOP_ADVLOCK(vp, (caddr_t)fp, F_SETLK, &lf, type); 370 if (error == 0) 371 fp->f_flag |= FHASLOCK; 372 373 vn_lock(vp, lock_flags | LK_RETRY); 374 return (error); 375 } 376 377 /* 378 * Common code for vnode open operations once a vnode is located. 379 * Check permissions, and call the VOP_OPEN routine. 380 */ 381 int 382 vn_open_vnode(struct vnode *vp, int fmode, struct ucred *cred, 383 struct thread *td, struct file *fp) 384 { 385 accmode_t accmode; 386 int error; 387 388 if (vp->v_type == VLNK) { 389 if ((fmode & O_PATH) == 0 || (fmode & FEXEC) != 0) 390 return (EMLINK); 391 } 392 if (vp->v_type == VSOCK) 393 return (EOPNOTSUPP); 394 if (vp->v_type != VDIR && fmode & O_DIRECTORY) 395 return (ENOTDIR); 396 397 accmode = 0; 398 if ((fmode & O_PATH) == 0) { 399 if ((fmode & (FWRITE | O_TRUNC)) != 0) { 400 if (vp->v_type == VDIR) 401 return (EISDIR); 402 accmode |= VWRITE; 403 } 404 if ((fmode & FREAD) != 0) 405 accmode |= VREAD; 406 if ((fmode & O_APPEND) && (fmode & FWRITE)) 407 accmode |= VAPPEND; 408 #ifdef MAC 409 if ((fmode & O_CREAT) != 0) 410 accmode |= VCREAT; 411 #endif 412 } 413 if ((fmode & FEXEC) != 0) 414 accmode |= VEXEC; 415 #ifdef MAC 416 if ((fmode & O_VERIFY) != 0) 417 accmode |= VVERIFY; 418 error = mac_vnode_check_open(cred, vp, accmode); 419 if (error != 0) 420 return (error); 421 422 accmode &= ~(VCREAT | VVERIFY); 423 #endif 424 if ((fmode & O_CREAT) == 0 && accmode != 0) { 425 error = VOP_ACCESS(vp, accmode, cred, td); 426 if (error != 0) 427 return (error); 428 } 429 if ((fmode & O_PATH) != 0) { 430 if (vp->v_type == VFIFO) 431 error = EPIPE; 432 else 433 error = VOP_ACCESS(vp, VREAD, cred, td); 434 if (error == 0) 435 fp->f_flag |= FKQALLOWED; 436 return (0); 437 } 438 439 if (vp->v_type == VFIFO && VOP_ISLOCKED(vp) != LK_EXCLUSIVE) 440 vn_lock(vp, LK_UPGRADE | LK_RETRY); 441 error = VOP_OPEN(vp, fmode, cred, td, fp); 442 if (error != 0) 443 return (error); 444 445 error = vn_open_vnode_advlock(vp, fmode, fp); 446 if (error == 0 && (fmode & FWRITE) != 0) { 447 error = VOP_ADD_WRITECOUNT(vp, 1); 448 if (error == 0) { 449 CTR3(KTR_VFS, "%s: vp %p v_writecount increased to %d", 450 __func__, vp, vp->v_writecount); 451 } 452 } 453 454 /* 455 * Error from advlock or VOP_ADD_WRITECOUNT() still requires 456 * calling VOP_CLOSE() to pair with earlier VOP_OPEN(). 457 */ 458 if (error != 0) { 459 if (fp != NULL) { 460 /* 461 * Arrange the call by having fdrop() to use 462 * vn_closefile(). This is to satisfy 463 * filesystems like devfs or tmpfs, which 464 * override fo_close(). 465 */ 466 fp->f_flag |= FOPENFAILED; 467 fp->f_vnode = vp; 468 if (fp->f_ops == &badfileops) { 469 fp->f_type = DTYPE_VNODE; 470 fp->f_ops = &vnops; 471 } 472 vref(vp); 473 } else { 474 /* 475 * If there is no fp, due to kernel-mode open, 476 * we can call VOP_CLOSE() now. 477 */ 478 if (vp->v_type != VFIFO && (fmode & FWRITE) != 0 && 479 !MNT_EXTENDED_SHARED(vp->v_mount) && 480 VOP_ISLOCKED(vp) != LK_EXCLUSIVE) 481 vn_lock(vp, LK_UPGRADE | LK_RETRY); 482 (void)VOP_CLOSE(vp, fmode & (FREAD | FWRITE | FEXEC), 483 cred, td); 484 } 485 } 486 487 ASSERT_VOP_LOCKED(vp, "vn_open_vnode"); 488 return (error); 489 490 } 491 492 /* 493 * Check for write permissions on the specified vnode. 494 * Prototype text segments cannot be written. 495 * It is racy. 496 */ 497 int 498 vn_writechk(struct vnode *vp) 499 { 500 501 ASSERT_VOP_LOCKED(vp, "vn_writechk"); 502 /* 503 * If there's shared text associated with 504 * the vnode, try to free it up once. If 505 * we fail, we can't allow writing. 506 */ 507 if (VOP_IS_TEXT(vp)) 508 return (ETXTBSY); 509 510 return (0); 511 } 512 513 /* 514 * Vnode close call 515 */ 516 static int 517 vn_close1(struct vnode *vp, int flags, struct ucred *file_cred, 518 struct thread *td, bool keep_ref) 519 { 520 struct mount *mp; 521 int error, lock_flags; 522 523 if (vp->v_type != VFIFO && (flags & FWRITE) == 0 && 524 MNT_EXTENDED_SHARED(vp->v_mount)) 525 lock_flags = LK_SHARED; 526 else 527 lock_flags = LK_EXCLUSIVE; 528 529 vn_start_write(vp, &mp, V_WAIT); 530 vn_lock(vp, lock_flags | LK_RETRY); 531 AUDIT_ARG_VNODE1(vp); 532 if ((flags & (FWRITE | FOPENFAILED)) == FWRITE) { 533 VOP_ADD_WRITECOUNT_CHECKED(vp, -1); 534 CTR3(KTR_VFS, "%s: vp %p v_writecount decreased to %d", 535 __func__, vp, vp->v_writecount); 536 } 537 error = VOP_CLOSE(vp, flags, file_cred, td); 538 if (keep_ref) 539 VOP_UNLOCK(vp); 540 else 541 vput(vp); 542 vn_finished_write(mp); 543 return (error); 544 } 545 546 int 547 vn_close(struct vnode *vp, int flags, struct ucred *file_cred, 548 struct thread *td) 549 { 550 551 return (vn_close1(vp, flags, file_cred, td, false)); 552 } 553 554 /* 555 * Heuristic to detect sequential operation. 556 */ 557 static int 558 sequential_heuristic(struct uio *uio, struct file *fp) 559 { 560 enum uio_rw rw; 561 562 ASSERT_VOP_LOCKED(fp->f_vnode, __func__); 563 564 rw = uio->uio_rw; 565 if (fp->f_flag & FRDAHEAD) 566 return (fp->f_seqcount[rw] << IO_SEQSHIFT); 567 568 /* 569 * Offset 0 is handled specially. open() sets f_seqcount to 1 so 570 * that the first I/O is normally considered to be slightly 571 * sequential. Seeking to offset 0 doesn't change sequentiality 572 * unless previous seeks have reduced f_seqcount to 0, in which 573 * case offset 0 is not special. 574 */ 575 if ((uio->uio_offset == 0 && fp->f_seqcount[rw] > 0) || 576 uio->uio_offset == fp->f_nextoff[rw]) { 577 /* 578 * f_seqcount is in units of fixed-size blocks so that it 579 * depends mainly on the amount of sequential I/O and not 580 * much on the number of sequential I/O's. The fixed size 581 * of 16384 is hard-coded here since it is (not quite) just 582 * a magic size that works well here. This size is more 583 * closely related to the best I/O size for real disks than 584 * to any block size used by software. 585 */ 586 if (uio->uio_resid >= IO_SEQMAX * 16384) 587 fp->f_seqcount[rw] = IO_SEQMAX; 588 else { 589 fp->f_seqcount[rw] += howmany(uio->uio_resid, 16384); 590 if (fp->f_seqcount[rw] > IO_SEQMAX) 591 fp->f_seqcount[rw] = IO_SEQMAX; 592 } 593 return (fp->f_seqcount[rw] << IO_SEQSHIFT); 594 } 595 596 /* Not sequential. Quickly draw-down sequentiality. */ 597 if (fp->f_seqcount[rw] > 1) 598 fp->f_seqcount[rw] = 1; 599 else 600 fp->f_seqcount[rw] = 0; 601 return (0); 602 } 603 604 /* 605 * Package up an I/O request on a vnode into a uio and do it. 606 */ 607 int 608 vn_rdwr(enum uio_rw rw, struct vnode *vp, void *base, int len, off_t offset, 609 enum uio_seg segflg, int ioflg, struct ucred *active_cred, 610 struct ucred *file_cred, ssize_t *aresid, struct thread *td) 611 { 612 struct uio auio; 613 struct iovec aiov; 614 struct mount *mp; 615 struct ucred *cred; 616 void *rl_cookie; 617 struct vn_io_fault_args args; 618 int error, lock_flags; 619 620 if (offset < 0 && vp->v_type != VCHR) 621 return (EINVAL); 622 auio.uio_iov = &aiov; 623 auio.uio_iovcnt = 1; 624 aiov.iov_base = base; 625 aiov.iov_len = len; 626 auio.uio_resid = len; 627 auio.uio_offset = offset; 628 auio.uio_segflg = segflg; 629 auio.uio_rw = rw; 630 auio.uio_td = td; 631 error = 0; 632 633 if ((ioflg & IO_NODELOCKED) == 0) { 634 if ((ioflg & IO_RANGELOCKED) == 0) { 635 if (rw == UIO_READ) { 636 rl_cookie = vn_rangelock_rlock(vp, offset, 637 offset + len); 638 } else if ((ioflg & IO_APPEND) != 0) { 639 rl_cookie = vn_rangelock_wlock(vp, 0, OFF_MAX); 640 } else { 641 rl_cookie = vn_rangelock_wlock(vp, offset, 642 offset + len); 643 } 644 } else 645 rl_cookie = NULL; 646 mp = NULL; 647 if (rw == UIO_WRITE) { 648 if (vp->v_type != VCHR && 649 (error = vn_start_write(vp, &mp, V_WAIT | PCATCH)) 650 != 0) 651 goto out; 652 if (MNT_SHARED_WRITES(mp) || 653 ((mp == NULL) && MNT_SHARED_WRITES(vp->v_mount))) 654 lock_flags = LK_SHARED; 655 else 656 lock_flags = LK_EXCLUSIVE; 657 } else 658 lock_flags = LK_SHARED; 659 vn_lock(vp, lock_flags | LK_RETRY); 660 } else 661 rl_cookie = NULL; 662 663 ASSERT_VOP_LOCKED(vp, "IO_NODELOCKED with no vp lock held"); 664 #ifdef MAC 665 if ((ioflg & IO_NOMACCHECK) == 0) { 666 if (rw == UIO_READ) 667 error = mac_vnode_check_read(active_cred, file_cred, 668 vp); 669 else 670 error = mac_vnode_check_write(active_cred, file_cred, 671 vp); 672 } 673 #endif 674 if (error == 0) { 675 if (file_cred != NULL) 676 cred = file_cred; 677 else 678 cred = active_cred; 679 if (do_vn_io_fault(vp, &auio)) { 680 args.kind = VN_IO_FAULT_VOP; 681 args.cred = cred; 682 args.flags = ioflg; 683 args.args.vop_args.vp = vp; 684 error = vn_io_fault1(vp, &auio, &args, td); 685 } else if (rw == UIO_READ) { 686 error = VOP_READ(vp, &auio, ioflg, cred); 687 } else /* if (rw == UIO_WRITE) */ { 688 error = VOP_WRITE(vp, &auio, ioflg, cred); 689 } 690 } 691 if (aresid) 692 *aresid = auio.uio_resid; 693 else 694 if (auio.uio_resid && error == 0) 695 error = EIO; 696 if ((ioflg & IO_NODELOCKED) == 0) { 697 VOP_UNLOCK(vp); 698 if (mp != NULL) 699 vn_finished_write(mp); 700 } 701 out: 702 if (rl_cookie != NULL) 703 vn_rangelock_unlock(vp, rl_cookie); 704 return (error); 705 } 706 707 /* 708 * Package up an I/O request on a vnode into a uio and do it. The I/O 709 * request is split up into smaller chunks and we try to avoid saturating 710 * the buffer cache while potentially holding a vnode locked, so we 711 * check bwillwrite() before calling vn_rdwr(). We also call kern_yield() 712 * to give other processes a chance to lock the vnode (either other processes 713 * core'ing the same binary, or unrelated processes scanning the directory). 714 */ 715 int 716 vn_rdwr_inchunks(enum uio_rw rw, struct vnode *vp, void *base, size_t len, 717 off_t offset, enum uio_seg segflg, int ioflg, struct ucred *active_cred, 718 struct ucred *file_cred, size_t *aresid, struct thread *td) 719 { 720 int error = 0; 721 ssize_t iaresid; 722 723 do { 724 int chunk; 725 726 /* 727 * Force `offset' to a multiple of MAXBSIZE except possibly 728 * for the first chunk, so that filesystems only need to 729 * write full blocks except possibly for the first and last 730 * chunks. 731 */ 732 chunk = MAXBSIZE - (uoff_t)offset % MAXBSIZE; 733 734 if (chunk > len) 735 chunk = len; 736 if (rw != UIO_READ && vp->v_type == VREG) 737 bwillwrite(); 738 iaresid = 0; 739 error = vn_rdwr(rw, vp, base, chunk, offset, segflg, 740 ioflg, active_cred, file_cred, &iaresid, td); 741 len -= chunk; /* aresid calc already includes length */ 742 if (error) 743 break; 744 offset += chunk; 745 base = (char *)base + chunk; 746 kern_yield(PRI_USER); 747 } while (len); 748 if (aresid) 749 *aresid = len + iaresid; 750 return (error); 751 } 752 753 #if OFF_MAX <= LONG_MAX 754 off_t 755 foffset_lock(struct file *fp, int flags) 756 { 757 volatile short *flagsp; 758 off_t res; 759 short state; 760 761 KASSERT((flags & FOF_OFFSET) == 0, ("FOF_OFFSET passed")); 762 763 if ((flags & FOF_NOLOCK) != 0) 764 return (atomic_load_long(&fp->f_offset)); 765 766 /* 767 * According to McKusick the vn lock was protecting f_offset here. 768 * It is now protected by the FOFFSET_LOCKED flag. 769 */ 770 flagsp = &fp->f_vnread_flags; 771 if (atomic_cmpset_acq_16(flagsp, 0, FOFFSET_LOCKED)) 772 return (atomic_load_long(&fp->f_offset)); 773 774 sleepq_lock(&fp->f_vnread_flags); 775 state = atomic_load_16(flagsp); 776 for (;;) { 777 if ((state & FOFFSET_LOCKED) == 0) { 778 if (!atomic_fcmpset_acq_16(flagsp, &state, 779 FOFFSET_LOCKED)) 780 continue; 781 break; 782 } 783 if ((state & FOFFSET_LOCK_WAITING) == 0) { 784 if (!atomic_fcmpset_acq_16(flagsp, &state, 785 state | FOFFSET_LOCK_WAITING)) 786 continue; 787 } 788 DROP_GIANT(); 789 sleepq_add(&fp->f_vnread_flags, NULL, "vofflock", 0, 0); 790 sleepq_wait(&fp->f_vnread_flags, PUSER -1); 791 PICKUP_GIANT(); 792 sleepq_lock(&fp->f_vnread_flags); 793 state = atomic_load_16(flagsp); 794 } 795 res = atomic_load_long(&fp->f_offset); 796 sleepq_release(&fp->f_vnread_flags); 797 return (res); 798 } 799 800 void 801 foffset_unlock(struct file *fp, off_t val, int flags) 802 { 803 volatile short *flagsp; 804 short state; 805 806 KASSERT((flags & FOF_OFFSET) == 0, ("FOF_OFFSET passed")); 807 808 if ((flags & FOF_NOUPDATE) == 0) 809 atomic_store_long(&fp->f_offset, val); 810 if ((flags & FOF_NEXTOFF_R) != 0) 811 fp->f_nextoff[UIO_READ] = val; 812 if ((flags & FOF_NEXTOFF_W) != 0) 813 fp->f_nextoff[UIO_WRITE] = val; 814 815 if ((flags & FOF_NOLOCK) != 0) 816 return; 817 818 flagsp = &fp->f_vnread_flags; 819 state = atomic_load_16(flagsp); 820 if ((state & FOFFSET_LOCK_WAITING) == 0 && 821 atomic_cmpset_rel_16(flagsp, state, 0)) 822 return; 823 824 sleepq_lock(&fp->f_vnread_flags); 825 MPASS((fp->f_vnread_flags & FOFFSET_LOCKED) != 0); 826 MPASS((fp->f_vnread_flags & FOFFSET_LOCK_WAITING) != 0); 827 fp->f_vnread_flags = 0; 828 sleepq_broadcast(&fp->f_vnread_flags, SLEEPQ_SLEEP, 0, 0); 829 sleepq_release(&fp->f_vnread_flags); 830 } 831 #else 832 off_t 833 foffset_lock(struct file *fp, int flags) 834 { 835 struct mtx *mtxp; 836 off_t res; 837 838 KASSERT((flags & FOF_OFFSET) == 0, ("FOF_OFFSET passed")); 839 840 mtxp = mtx_pool_find(mtxpool_sleep, fp); 841 mtx_lock(mtxp); 842 if ((flags & FOF_NOLOCK) == 0) { 843 while (fp->f_vnread_flags & FOFFSET_LOCKED) { 844 fp->f_vnread_flags |= FOFFSET_LOCK_WAITING; 845 msleep(&fp->f_vnread_flags, mtxp, PUSER -1, 846 "vofflock", 0); 847 } 848 fp->f_vnread_flags |= FOFFSET_LOCKED; 849 } 850 res = fp->f_offset; 851 mtx_unlock(mtxp); 852 return (res); 853 } 854 855 void 856 foffset_unlock(struct file *fp, off_t val, int flags) 857 { 858 struct mtx *mtxp; 859 860 KASSERT((flags & FOF_OFFSET) == 0, ("FOF_OFFSET passed")); 861 862 mtxp = mtx_pool_find(mtxpool_sleep, fp); 863 mtx_lock(mtxp); 864 if ((flags & FOF_NOUPDATE) == 0) 865 fp->f_offset = val; 866 if ((flags & FOF_NEXTOFF_R) != 0) 867 fp->f_nextoff[UIO_READ] = val; 868 if ((flags & FOF_NEXTOFF_W) != 0) 869 fp->f_nextoff[UIO_WRITE] = val; 870 if ((flags & FOF_NOLOCK) == 0) { 871 KASSERT((fp->f_vnread_flags & FOFFSET_LOCKED) != 0, 872 ("Lost FOFFSET_LOCKED")); 873 if (fp->f_vnread_flags & FOFFSET_LOCK_WAITING) 874 wakeup(&fp->f_vnread_flags); 875 fp->f_vnread_flags = 0; 876 } 877 mtx_unlock(mtxp); 878 } 879 #endif 880 881 void 882 foffset_lock_uio(struct file *fp, struct uio *uio, int flags) 883 { 884 885 if ((flags & FOF_OFFSET) == 0) 886 uio->uio_offset = foffset_lock(fp, flags); 887 } 888 889 void 890 foffset_unlock_uio(struct file *fp, struct uio *uio, int flags) 891 { 892 893 if ((flags & FOF_OFFSET) == 0) 894 foffset_unlock(fp, uio->uio_offset, flags); 895 } 896 897 static int 898 get_advice(struct file *fp, struct uio *uio) 899 { 900 struct mtx *mtxp; 901 int ret; 902 903 ret = POSIX_FADV_NORMAL; 904 if (fp->f_advice == NULL || fp->f_vnode->v_type != VREG) 905 return (ret); 906 907 mtxp = mtx_pool_find(mtxpool_sleep, fp); 908 mtx_lock(mtxp); 909 if (fp->f_advice != NULL && 910 uio->uio_offset >= fp->f_advice->fa_start && 911 uio->uio_offset + uio->uio_resid <= fp->f_advice->fa_end) 912 ret = fp->f_advice->fa_advice; 913 mtx_unlock(mtxp); 914 return (ret); 915 } 916 917 int 918 vn_read_from_obj(struct vnode *vp, struct uio *uio) 919 { 920 vm_object_t obj; 921 vm_page_t ma[io_hold_cnt + 2]; 922 off_t off, vsz; 923 ssize_t resid; 924 int error, i, j; 925 926 MPASS(uio->uio_resid <= ptoa(io_hold_cnt + 2)); 927 obj = atomic_load_ptr(&vp->v_object); 928 if (obj == NULL) 929 return (EJUSTRETURN); 930 931 /* 932 * Depends on type stability of vm_objects. 933 */ 934 vm_object_pip_add(obj, 1); 935 if ((obj->flags & OBJ_DEAD) != 0) { 936 /* 937 * Note that object might be already reused from the 938 * vnode, and the OBJ_DEAD flag cleared. This is fine, 939 * we recheck for DOOMED vnode state after all pages 940 * are busied, and retract then. 941 * 942 * But we check for OBJ_DEAD to ensure that we do not 943 * busy pages while vm_object_terminate_pages() 944 * processes the queue. 945 */ 946 error = EJUSTRETURN; 947 goto out_pip; 948 } 949 950 resid = uio->uio_resid; 951 off = uio->uio_offset; 952 for (i = 0; resid > 0; i++) { 953 MPASS(i < io_hold_cnt + 2); 954 ma[i] = vm_page_grab_unlocked(obj, atop(off), 955 VM_ALLOC_NOCREAT | VM_ALLOC_SBUSY | VM_ALLOC_IGN_SBUSY | 956 VM_ALLOC_NOWAIT); 957 if (ma[i] == NULL) 958 break; 959 960 /* 961 * Skip invalid pages. Valid mask can be partial only 962 * at EOF, and we clip later. 963 */ 964 if (vm_page_none_valid(ma[i])) { 965 vm_page_sunbusy(ma[i]); 966 break; 967 } 968 969 resid -= PAGE_SIZE; 970 off += PAGE_SIZE; 971 } 972 if (i == 0) { 973 error = EJUSTRETURN; 974 goto out_pip; 975 } 976 977 /* 978 * Check VIRF_DOOMED after we busied our pages. Since 979 * vgonel() terminates the vnode' vm_object, it cannot 980 * process past pages busied by us. 981 */ 982 if (VN_IS_DOOMED(vp)) { 983 error = EJUSTRETURN; 984 goto out; 985 } 986 987 resid = PAGE_SIZE - (uio->uio_offset & PAGE_MASK) + ptoa(i - 1); 988 if (resid > uio->uio_resid) 989 resid = uio->uio_resid; 990 991 /* 992 * Unlocked read of vnp_size is safe because truncation cannot 993 * pass busied page. But we load vnp_size into a local 994 * variable so that possible concurrent extension does not 995 * break calculation. 996 */ 997 #if defined(__powerpc__) && !defined(__powerpc64__) 998 vsz = obj->un_pager.vnp.vnp_size; 999 #else 1000 vsz = atomic_load_64(&obj->un_pager.vnp.vnp_size); 1001 #endif 1002 if (uio->uio_offset >= vsz) { 1003 error = EJUSTRETURN; 1004 goto out; 1005 } 1006 if (uio->uio_offset + resid > vsz) 1007 resid = vsz - uio->uio_offset; 1008 1009 error = vn_io_fault_pgmove(ma, uio->uio_offset & PAGE_MASK, resid, uio); 1010 1011 out: 1012 for (j = 0; j < i; j++) { 1013 if (error == 0) 1014 vm_page_reference(ma[j]); 1015 vm_page_sunbusy(ma[j]); 1016 } 1017 out_pip: 1018 vm_object_pip_wakeup(obj); 1019 if (error != 0) 1020 return (error); 1021 return (uio->uio_resid == 0 ? 0 : EJUSTRETURN); 1022 } 1023 1024 /* 1025 * File table vnode read routine. 1026 */ 1027 static int 1028 vn_read(struct file *fp, struct uio *uio, struct ucred *active_cred, int flags, 1029 struct thread *td) 1030 { 1031 struct vnode *vp; 1032 off_t orig_offset; 1033 int error, ioflag; 1034 int advice; 1035 1036 KASSERT(uio->uio_td == td, ("uio_td %p is not td %p", 1037 uio->uio_td, td)); 1038 KASSERT(flags & FOF_OFFSET, ("No FOF_OFFSET")); 1039 vp = fp->f_vnode; 1040 ioflag = 0; 1041 if (fp->f_flag & FNONBLOCK) 1042 ioflag |= IO_NDELAY; 1043 if (fp->f_flag & O_DIRECT) 1044 ioflag |= IO_DIRECT; 1045 1046 /* 1047 * Try to read from page cache. VIRF_DOOMED check is racy but 1048 * allows us to avoid unneeded work outright. 1049 */ 1050 if (vn_io_pgcache_read_enable && !mac_vnode_check_read_enabled() && 1051 (vn_irflag_read(vp) & (VIRF_DOOMED | VIRF_PGREAD)) == VIRF_PGREAD) { 1052 error = VOP_READ_PGCACHE(vp, uio, ioflag, fp->f_cred); 1053 if (error == 0) { 1054 fp->f_nextoff[UIO_READ] = uio->uio_offset; 1055 return (0); 1056 } 1057 if (error != EJUSTRETURN) 1058 return (error); 1059 } 1060 1061 advice = get_advice(fp, uio); 1062 vn_lock(vp, LK_SHARED | LK_RETRY); 1063 1064 switch (advice) { 1065 case POSIX_FADV_NORMAL: 1066 case POSIX_FADV_SEQUENTIAL: 1067 case POSIX_FADV_NOREUSE: 1068 ioflag |= sequential_heuristic(uio, fp); 1069 break; 1070 case POSIX_FADV_RANDOM: 1071 /* Disable read-ahead for random I/O. */ 1072 break; 1073 } 1074 orig_offset = uio->uio_offset; 1075 1076 #ifdef MAC 1077 error = mac_vnode_check_read(active_cred, fp->f_cred, vp); 1078 if (error == 0) 1079 #endif 1080 error = VOP_READ(vp, uio, ioflag, fp->f_cred); 1081 fp->f_nextoff[UIO_READ] = uio->uio_offset; 1082 VOP_UNLOCK(vp); 1083 if (error == 0 && advice == POSIX_FADV_NOREUSE && 1084 orig_offset != uio->uio_offset) 1085 /* 1086 * Use POSIX_FADV_DONTNEED to flush pages and buffers 1087 * for the backing file after a POSIX_FADV_NOREUSE 1088 * read(2). 1089 */ 1090 error = VOP_ADVISE(vp, orig_offset, uio->uio_offset - 1, 1091 POSIX_FADV_DONTNEED); 1092 return (error); 1093 } 1094 1095 /* 1096 * File table vnode write routine. 1097 */ 1098 static int 1099 vn_write(struct file *fp, struct uio *uio, struct ucred *active_cred, int flags, 1100 struct thread *td) 1101 { 1102 struct vnode *vp; 1103 struct mount *mp; 1104 off_t orig_offset; 1105 int error, ioflag, lock_flags; 1106 int advice; 1107 1108 KASSERT(uio->uio_td == td, ("uio_td %p is not td %p", 1109 uio->uio_td, td)); 1110 KASSERT(flags & FOF_OFFSET, ("No FOF_OFFSET")); 1111 vp = fp->f_vnode; 1112 if (vp->v_type == VREG) 1113 bwillwrite(); 1114 ioflag = IO_UNIT; 1115 if (vp->v_type == VREG && (fp->f_flag & O_APPEND)) 1116 ioflag |= IO_APPEND; 1117 if (fp->f_flag & FNONBLOCK) 1118 ioflag |= IO_NDELAY; 1119 if (fp->f_flag & O_DIRECT) 1120 ioflag |= IO_DIRECT; 1121 if ((fp->f_flag & O_FSYNC) || 1122 (vp->v_mount && (vp->v_mount->mnt_flag & MNT_SYNCHRONOUS))) 1123 ioflag |= IO_SYNC; 1124 /* 1125 * For O_DSYNC we set both IO_SYNC and IO_DATASYNC, so that VOP_WRITE() 1126 * implementations that don't understand IO_DATASYNC fall back to full 1127 * O_SYNC behavior. 1128 */ 1129 if (fp->f_flag & O_DSYNC) 1130 ioflag |= IO_SYNC | IO_DATASYNC; 1131 mp = NULL; 1132 if (vp->v_type != VCHR && 1133 (error = vn_start_write(vp, &mp, V_WAIT | PCATCH)) != 0) 1134 goto unlock; 1135 1136 advice = get_advice(fp, uio); 1137 1138 if (MNT_SHARED_WRITES(mp) || 1139 (mp == NULL && MNT_SHARED_WRITES(vp->v_mount))) { 1140 lock_flags = LK_SHARED; 1141 } else { 1142 lock_flags = LK_EXCLUSIVE; 1143 } 1144 1145 vn_lock(vp, lock_flags | LK_RETRY); 1146 switch (advice) { 1147 case POSIX_FADV_NORMAL: 1148 case POSIX_FADV_SEQUENTIAL: 1149 case POSIX_FADV_NOREUSE: 1150 ioflag |= sequential_heuristic(uio, fp); 1151 break; 1152 case POSIX_FADV_RANDOM: 1153 /* XXX: Is this correct? */ 1154 break; 1155 } 1156 orig_offset = uio->uio_offset; 1157 1158 #ifdef MAC 1159 error = mac_vnode_check_write(active_cred, fp->f_cred, vp); 1160 if (error == 0) 1161 #endif 1162 error = VOP_WRITE(vp, uio, ioflag, fp->f_cred); 1163 fp->f_nextoff[UIO_WRITE] = uio->uio_offset; 1164 VOP_UNLOCK(vp); 1165 if (vp->v_type != VCHR) 1166 vn_finished_write(mp); 1167 if (error == 0 && advice == POSIX_FADV_NOREUSE && 1168 orig_offset != uio->uio_offset) 1169 /* 1170 * Use POSIX_FADV_DONTNEED to flush pages and buffers 1171 * for the backing file after a POSIX_FADV_NOREUSE 1172 * write(2). 1173 */ 1174 error = VOP_ADVISE(vp, orig_offset, uio->uio_offset - 1, 1175 POSIX_FADV_DONTNEED); 1176 unlock: 1177 return (error); 1178 } 1179 1180 /* 1181 * The vn_io_fault() is a wrapper around vn_read() and vn_write() to 1182 * prevent the following deadlock: 1183 * 1184 * Assume that the thread A reads from the vnode vp1 into userspace 1185 * buffer buf1 backed by the pages of vnode vp2. If a page in buf1 is 1186 * currently not resident, then system ends up with the call chain 1187 * vn_read() -> VOP_READ(vp1) -> uiomove() -> [Page Fault] -> 1188 * vm_fault(buf1) -> vnode_pager_getpages(vp2) -> VOP_GETPAGES(vp2) 1189 * which establishes lock order vp1->vn_lock, then vp2->vn_lock. 1190 * If, at the same time, thread B reads from vnode vp2 into buffer buf2 1191 * backed by the pages of vnode vp1, and some page in buf2 is not 1192 * resident, we get a reversed order vp2->vn_lock, then vp1->vn_lock. 1193 * 1194 * To prevent the lock order reversal and deadlock, vn_io_fault() does 1195 * not allow page faults to happen during VOP_READ() or VOP_WRITE(). 1196 * Instead, it first tries to do the whole range i/o with pagefaults 1197 * disabled. If all pages in the i/o buffer are resident and mapped, 1198 * VOP will succeed (ignoring the genuine filesystem errors). 1199 * Otherwise, we get back EFAULT, and vn_io_fault() falls back to do 1200 * i/o in chunks, with all pages in the chunk prefaulted and held 1201 * using vm_fault_quick_hold_pages(). 1202 * 1203 * Filesystems using this deadlock avoidance scheme should use the 1204 * array of the held pages from uio, saved in the curthread->td_ma, 1205 * instead of doing uiomove(). A helper function 1206 * vn_io_fault_uiomove() converts uiomove request into 1207 * uiomove_fromphys() over td_ma array. 1208 * 1209 * Since vnode locks do not cover the whole i/o anymore, rangelocks 1210 * make the current i/o request atomic with respect to other i/os and 1211 * truncations. 1212 */ 1213 1214 /* 1215 * Decode vn_io_fault_args and perform the corresponding i/o. 1216 */ 1217 static int 1218 vn_io_fault_doio(struct vn_io_fault_args *args, struct uio *uio, 1219 struct thread *td) 1220 { 1221 int error, save; 1222 1223 error = 0; 1224 save = vm_fault_disable_pagefaults(); 1225 switch (args->kind) { 1226 case VN_IO_FAULT_FOP: 1227 error = (args->args.fop_args.doio)(args->args.fop_args.fp, 1228 uio, args->cred, args->flags, td); 1229 break; 1230 case VN_IO_FAULT_VOP: 1231 if (uio->uio_rw == UIO_READ) { 1232 error = VOP_READ(args->args.vop_args.vp, uio, 1233 args->flags, args->cred); 1234 } else if (uio->uio_rw == UIO_WRITE) { 1235 error = VOP_WRITE(args->args.vop_args.vp, uio, 1236 args->flags, args->cred); 1237 } 1238 break; 1239 default: 1240 panic("vn_io_fault_doio: unknown kind of io %d %d", 1241 args->kind, uio->uio_rw); 1242 } 1243 vm_fault_enable_pagefaults(save); 1244 return (error); 1245 } 1246 1247 static int 1248 vn_io_fault_touch(char *base, const struct uio *uio) 1249 { 1250 int r; 1251 1252 r = fubyte(base); 1253 if (r == -1 || (uio->uio_rw == UIO_READ && subyte(base, r) == -1)) 1254 return (EFAULT); 1255 return (0); 1256 } 1257 1258 static int 1259 vn_io_fault_prefault_user(const struct uio *uio) 1260 { 1261 char *base; 1262 const struct iovec *iov; 1263 size_t len; 1264 ssize_t resid; 1265 int error, i; 1266 1267 KASSERT(uio->uio_segflg == UIO_USERSPACE, 1268 ("vn_io_fault_prefault userspace")); 1269 1270 error = i = 0; 1271 iov = uio->uio_iov; 1272 resid = uio->uio_resid; 1273 base = iov->iov_base; 1274 len = iov->iov_len; 1275 while (resid > 0) { 1276 error = vn_io_fault_touch(base, uio); 1277 if (error != 0) 1278 break; 1279 if (len < PAGE_SIZE) { 1280 if (len != 0) { 1281 error = vn_io_fault_touch(base + len - 1, uio); 1282 if (error != 0) 1283 break; 1284 resid -= len; 1285 } 1286 if (++i >= uio->uio_iovcnt) 1287 break; 1288 iov = uio->uio_iov + i; 1289 base = iov->iov_base; 1290 len = iov->iov_len; 1291 } else { 1292 len -= PAGE_SIZE; 1293 base += PAGE_SIZE; 1294 resid -= PAGE_SIZE; 1295 } 1296 } 1297 return (error); 1298 } 1299 1300 /* 1301 * Common code for vn_io_fault(), agnostic to the kind of i/o request. 1302 * Uses vn_io_fault_doio() to make the call to an actual i/o function. 1303 * Used from vn_rdwr() and vn_io_fault(), which encode the i/o request 1304 * into args and call vn_io_fault1() to handle faults during the user 1305 * mode buffer accesses. 1306 */ 1307 static int 1308 vn_io_fault1(struct vnode *vp, struct uio *uio, struct vn_io_fault_args *args, 1309 struct thread *td) 1310 { 1311 vm_page_t ma[io_hold_cnt + 2]; 1312 struct uio *uio_clone, short_uio; 1313 struct iovec short_iovec[1]; 1314 vm_page_t *prev_td_ma; 1315 vm_prot_t prot; 1316 vm_offset_t addr, end; 1317 size_t len, resid; 1318 ssize_t adv; 1319 int error, cnt, saveheld, prev_td_ma_cnt; 1320 1321 if (vn_io_fault_prefault) { 1322 error = vn_io_fault_prefault_user(uio); 1323 if (error != 0) 1324 return (error); /* Or ignore ? */ 1325 } 1326 1327 prot = uio->uio_rw == UIO_READ ? VM_PROT_WRITE : VM_PROT_READ; 1328 1329 /* 1330 * The UFS follows IO_UNIT directive and replays back both 1331 * uio_offset and uio_resid if an error is encountered during the 1332 * operation. But, since the iovec may be already advanced, 1333 * uio is still in an inconsistent state. 1334 * 1335 * Cache a copy of the original uio, which is advanced to the redo 1336 * point using UIO_NOCOPY below. 1337 */ 1338 uio_clone = cloneuio(uio); 1339 resid = uio->uio_resid; 1340 1341 short_uio.uio_segflg = UIO_USERSPACE; 1342 short_uio.uio_rw = uio->uio_rw; 1343 short_uio.uio_td = uio->uio_td; 1344 1345 error = vn_io_fault_doio(args, uio, td); 1346 if (error != EFAULT) 1347 goto out; 1348 1349 atomic_add_long(&vn_io_faults_cnt, 1); 1350 uio_clone->uio_segflg = UIO_NOCOPY; 1351 uiomove(NULL, resid - uio->uio_resid, uio_clone); 1352 uio_clone->uio_segflg = uio->uio_segflg; 1353 1354 saveheld = curthread_pflags_set(TDP_UIOHELD); 1355 prev_td_ma = td->td_ma; 1356 prev_td_ma_cnt = td->td_ma_cnt; 1357 1358 while (uio_clone->uio_resid != 0) { 1359 len = uio_clone->uio_iov->iov_len; 1360 if (len == 0) { 1361 KASSERT(uio_clone->uio_iovcnt >= 1, 1362 ("iovcnt underflow")); 1363 uio_clone->uio_iov++; 1364 uio_clone->uio_iovcnt--; 1365 continue; 1366 } 1367 if (len > ptoa(io_hold_cnt)) 1368 len = ptoa(io_hold_cnt); 1369 addr = (uintptr_t)uio_clone->uio_iov->iov_base; 1370 end = round_page(addr + len); 1371 if (end < addr) { 1372 error = EFAULT; 1373 break; 1374 } 1375 cnt = atop(end - trunc_page(addr)); 1376 /* 1377 * A perfectly misaligned address and length could cause 1378 * both the start and the end of the chunk to use partial 1379 * page. +2 accounts for such a situation. 1380 */ 1381 cnt = vm_fault_quick_hold_pages(&td->td_proc->p_vmspace->vm_map, 1382 addr, len, prot, ma, io_hold_cnt + 2); 1383 if (cnt == -1) { 1384 error = EFAULT; 1385 break; 1386 } 1387 short_uio.uio_iov = &short_iovec[0]; 1388 short_iovec[0].iov_base = (void *)addr; 1389 short_uio.uio_iovcnt = 1; 1390 short_uio.uio_resid = short_iovec[0].iov_len = len; 1391 short_uio.uio_offset = uio_clone->uio_offset; 1392 td->td_ma = ma; 1393 td->td_ma_cnt = cnt; 1394 1395 error = vn_io_fault_doio(args, &short_uio, td); 1396 vm_page_unhold_pages(ma, cnt); 1397 adv = len - short_uio.uio_resid; 1398 1399 uio_clone->uio_iov->iov_base = 1400 (char *)uio_clone->uio_iov->iov_base + adv; 1401 uio_clone->uio_iov->iov_len -= adv; 1402 uio_clone->uio_resid -= adv; 1403 uio_clone->uio_offset += adv; 1404 1405 uio->uio_resid -= adv; 1406 uio->uio_offset += adv; 1407 1408 if (error != 0 || adv == 0) 1409 break; 1410 } 1411 td->td_ma = prev_td_ma; 1412 td->td_ma_cnt = prev_td_ma_cnt; 1413 curthread_pflags_restore(saveheld); 1414 out: 1415 free(uio_clone, M_IOV); 1416 return (error); 1417 } 1418 1419 static int 1420 vn_io_fault(struct file *fp, struct uio *uio, struct ucred *active_cred, 1421 int flags, struct thread *td) 1422 { 1423 fo_rdwr_t *doio; 1424 struct vnode *vp; 1425 void *rl_cookie; 1426 struct vn_io_fault_args args; 1427 int error; 1428 1429 doio = uio->uio_rw == UIO_READ ? vn_read : vn_write; 1430 vp = fp->f_vnode; 1431 1432 /* 1433 * The ability to read(2) on a directory has historically been 1434 * allowed for all users, but this can and has been the source of 1435 * at least one security issue in the past. As such, it is now hidden 1436 * away behind a sysctl for those that actually need it to use it, and 1437 * restricted to root when it's turned on to make it relatively safe to 1438 * leave on for longer sessions of need. 1439 */ 1440 if (vp->v_type == VDIR) { 1441 KASSERT(uio->uio_rw == UIO_READ, 1442 ("illegal write attempted on a directory")); 1443 if (!vfs_allow_read_dir) 1444 return (EISDIR); 1445 if ((error = priv_check(td, PRIV_VFS_READ_DIR)) != 0) 1446 return (EISDIR); 1447 } 1448 1449 foffset_lock_uio(fp, uio, flags); 1450 if (do_vn_io_fault(vp, uio)) { 1451 args.kind = VN_IO_FAULT_FOP; 1452 args.args.fop_args.fp = fp; 1453 args.args.fop_args.doio = doio; 1454 args.cred = active_cred; 1455 args.flags = flags | FOF_OFFSET; 1456 if (uio->uio_rw == UIO_READ) { 1457 rl_cookie = vn_rangelock_rlock(vp, uio->uio_offset, 1458 uio->uio_offset + uio->uio_resid); 1459 } else if ((fp->f_flag & O_APPEND) != 0 || 1460 (flags & FOF_OFFSET) == 0) { 1461 /* For appenders, punt and lock the whole range. */ 1462 rl_cookie = vn_rangelock_wlock(vp, 0, OFF_MAX); 1463 } else { 1464 rl_cookie = vn_rangelock_wlock(vp, uio->uio_offset, 1465 uio->uio_offset + uio->uio_resid); 1466 } 1467 error = vn_io_fault1(vp, uio, &args, td); 1468 vn_rangelock_unlock(vp, rl_cookie); 1469 } else { 1470 error = doio(fp, uio, active_cred, flags | FOF_OFFSET, td); 1471 } 1472 foffset_unlock_uio(fp, uio, flags); 1473 return (error); 1474 } 1475 1476 /* 1477 * Helper function to perform the requested uiomove operation using 1478 * the held pages for io->uio_iov[0].iov_base buffer instead of 1479 * copyin/copyout. Access to the pages with uiomove_fromphys() 1480 * instead of iov_base prevents page faults that could occur due to 1481 * pmap_collect() invalidating the mapping created by 1482 * vm_fault_quick_hold_pages(), or pageout daemon, page laundry or 1483 * object cleanup revoking the write access from page mappings. 1484 * 1485 * Filesystems specified MNTK_NO_IOPF shall use vn_io_fault_uiomove() 1486 * instead of plain uiomove(). 1487 */ 1488 int 1489 vn_io_fault_uiomove(char *data, int xfersize, struct uio *uio) 1490 { 1491 struct uio transp_uio; 1492 struct iovec transp_iov[1]; 1493 struct thread *td; 1494 size_t adv; 1495 int error, pgadv; 1496 1497 td = curthread; 1498 if ((td->td_pflags & TDP_UIOHELD) == 0 || 1499 uio->uio_segflg != UIO_USERSPACE) 1500 return (uiomove(data, xfersize, uio)); 1501 1502 KASSERT(uio->uio_iovcnt == 1, ("uio_iovcnt %d", uio->uio_iovcnt)); 1503 transp_iov[0].iov_base = data; 1504 transp_uio.uio_iov = &transp_iov[0]; 1505 transp_uio.uio_iovcnt = 1; 1506 if (xfersize > uio->uio_resid) 1507 xfersize = uio->uio_resid; 1508 transp_uio.uio_resid = transp_iov[0].iov_len = xfersize; 1509 transp_uio.uio_offset = 0; 1510 transp_uio.uio_segflg = UIO_SYSSPACE; 1511 /* 1512 * Since transp_iov points to data, and td_ma page array 1513 * corresponds to original uio->uio_iov, we need to invert the 1514 * direction of the i/o operation as passed to 1515 * uiomove_fromphys(). 1516 */ 1517 switch (uio->uio_rw) { 1518 case UIO_WRITE: 1519 transp_uio.uio_rw = UIO_READ; 1520 break; 1521 case UIO_READ: 1522 transp_uio.uio_rw = UIO_WRITE; 1523 break; 1524 } 1525 transp_uio.uio_td = uio->uio_td; 1526 error = uiomove_fromphys(td->td_ma, 1527 ((vm_offset_t)uio->uio_iov->iov_base) & PAGE_MASK, 1528 xfersize, &transp_uio); 1529 adv = xfersize - transp_uio.uio_resid; 1530 pgadv = 1531 (((vm_offset_t)uio->uio_iov->iov_base + adv) >> PAGE_SHIFT) - 1532 (((vm_offset_t)uio->uio_iov->iov_base) >> PAGE_SHIFT); 1533 td->td_ma += pgadv; 1534 KASSERT(td->td_ma_cnt >= pgadv, ("consumed pages %d %d", td->td_ma_cnt, 1535 pgadv)); 1536 td->td_ma_cnt -= pgadv; 1537 uio->uio_iov->iov_base = (char *)uio->uio_iov->iov_base + adv; 1538 uio->uio_iov->iov_len -= adv; 1539 uio->uio_resid -= adv; 1540 uio->uio_offset += adv; 1541 return (error); 1542 } 1543 1544 int 1545 vn_io_fault_pgmove(vm_page_t ma[], vm_offset_t offset, int xfersize, 1546 struct uio *uio) 1547 { 1548 struct thread *td; 1549 vm_offset_t iov_base; 1550 int cnt, pgadv; 1551 1552 td = curthread; 1553 if ((td->td_pflags & TDP_UIOHELD) == 0 || 1554 uio->uio_segflg != UIO_USERSPACE) 1555 return (uiomove_fromphys(ma, offset, xfersize, uio)); 1556 1557 KASSERT(uio->uio_iovcnt == 1, ("uio_iovcnt %d", uio->uio_iovcnt)); 1558 cnt = xfersize > uio->uio_resid ? uio->uio_resid : xfersize; 1559 iov_base = (vm_offset_t)uio->uio_iov->iov_base; 1560 switch (uio->uio_rw) { 1561 case UIO_WRITE: 1562 pmap_copy_pages(td->td_ma, iov_base & PAGE_MASK, ma, 1563 offset, cnt); 1564 break; 1565 case UIO_READ: 1566 pmap_copy_pages(ma, offset, td->td_ma, iov_base & PAGE_MASK, 1567 cnt); 1568 break; 1569 } 1570 pgadv = ((iov_base + cnt) >> PAGE_SHIFT) - (iov_base >> PAGE_SHIFT); 1571 td->td_ma += pgadv; 1572 KASSERT(td->td_ma_cnt >= pgadv, ("consumed pages %d %d", td->td_ma_cnt, 1573 pgadv)); 1574 td->td_ma_cnt -= pgadv; 1575 uio->uio_iov->iov_base = (char *)(iov_base + cnt); 1576 uio->uio_iov->iov_len -= cnt; 1577 uio->uio_resid -= cnt; 1578 uio->uio_offset += cnt; 1579 return (0); 1580 } 1581 1582 /* 1583 * File table truncate routine. 1584 */ 1585 static int 1586 vn_truncate(struct file *fp, off_t length, struct ucred *active_cred, 1587 struct thread *td) 1588 { 1589 struct mount *mp; 1590 struct vnode *vp; 1591 void *rl_cookie; 1592 int error; 1593 1594 vp = fp->f_vnode; 1595 1596 retry: 1597 /* 1598 * Lock the whole range for truncation. Otherwise split i/o 1599 * might happen partly before and partly after the truncation. 1600 */ 1601 rl_cookie = vn_rangelock_wlock(vp, 0, OFF_MAX); 1602 error = vn_start_write(vp, &mp, V_WAIT | PCATCH); 1603 if (error) 1604 goto out1; 1605 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 1606 AUDIT_ARG_VNODE1(vp); 1607 if (vp->v_type == VDIR) { 1608 error = EISDIR; 1609 goto out; 1610 } 1611 #ifdef MAC 1612 error = mac_vnode_check_write(active_cred, fp->f_cred, vp); 1613 if (error) 1614 goto out; 1615 #endif 1616 error = vn_truncate_locked(vp, length, (fp->f_flag & O_FSYNC) != 0, 1617 fp->f_cred); 1618 out: 1619 VOP_UNLOCK(vp); 1620 vn_finished_write(mp); 1621 out1: 1622 vn_rangelock_unlock(vp, rl_cookie); 1623 if (error == ERELOOKUP) 1624 goto retry; 1625 return (error); 1626 } 1627 1628 /* 1629 * Truncate a file that is already locked. 1630 */ 1631 int 1632 vn_truncate_locked(struct vnode *vp, off_t length, bool sync, 1633 struct ucred *cred) 1634 { 1635 struct vattr vattr; 1636 int error; 1637 1638 error = VOP_ADD_WRITECOUNT(vp, 1); 1639 if (error == 0) { 1640 VATTR_NULL(&vattr); 1641 vattr.va_size = length; 1642 if (sync) 1643 vattr.va_vaflags |= VA_SYNC; 1644 error = VOP_SETATTR(vp, &vattr, cred); 1645 VOP_ADD_WRITECOUNT_CHECKED(vp, -1); 1646 } 1647 return (error); 1648 } 1649 1650 /* 1651 * File table vnode stat routine. 1652 */ 1653 int 1654 vn_statfile(struct file *fp, struct stat *sb, struct ucred *active_cred, 1655 struct thread *td) 1656 { 1657 struct vnode *vp = fp->f_vnode; 1658 int error; 1659 1660 vn_lock(vp, LK_SHARED | LK_RETRY); 1661 error = VOP_STAT(vp, sb, active_cred, fp->f_cred, td); 1662 VOP_UNLOCK(vp); 1663 1664 return (error); 1665 } 1666 1667 /* 1668 * File table vnode ioctl routine. 1669 */ 1670 static int 1671 vn_ioctl(struct file *fp, u_long com, void *data, struct ucred *active_cred, 1672 struct thread *td) 1673 { 1674 struct vattr vattr; 1675 struct vnode *vp; 1676 struct fiobmap2_arg *bmarg; 1677 int error; 1678 1679 vp = fp->f_vnode; 1680 switch (vp->v_type) { 1681 case VDIR: 1682 case VREG: 1683 switch (com) { 1684 case FIONREAD: 1685 vn_lock(vp, LK_SHARED | LK_RETRY); 1686 error = VOP_GETATTR(vp, &vattr, active_cred); 1687 VOP_UNLOCK(vp); 1688 if (error == 0) 1689 *(int *)data = vattr.va_size - fp->f_offset; 1690 return (error); 1691 case FIOBMAP2: 1692 bmarg = (struct fiobmap2_arg *)data; 1693 vn_lock(vp, LK_SHARED | LK_RETRY); 1694 #ifdef MAC 1695 error = mac_vnode_check_read(active_cred, fp->f_cred, 1696 vp); 1697 if (error == 0) 1698 #endif 1699 error = VOP_BMAP(vp, bmarg->bn, NULL, 1700 &bmarg->bn, &bmarg->runp, &bmarg->runb); 1701 VOP_UNLOCK(vp); 1702 return (error); 1703 case FIONBIO: 1704 case FIOASYNC: 1705 return (0); 1706 default: 1707 return (VOP_IOCTL(vp, com, data, fp->f_flag, 1708 active_cred, td)); 1709 } 1710 break; 1711 case VCHR: 1712 return (VOP_IOCTL(vp, com, data, fp->f_flag, 1713 active_cred, td)); 1714 default: 1715 return (ENOTTY); 1716 } 1717 } 1718 1719 /* 1720 * File table vnode poll routine. 1721 */ 1722 static int 1723 vn_poll(struct file *fp, int events, struct ucred *active_cred, 1724 struct thread *td) 1725 { 1726 struct vnode *vp; 1727 int error; 1728 1729 vp = fp->f_vnode; 1730 #if defined(MAC) || defined(AUDIT) 1731 if (AUDITING_TD(td) || mac_vnode_check_poll_enabled()) { 1732 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 1733 AUDIT_ARG_VNODE1(vp); 1734 error = mac_vnode_check_poll(active_cred, fp->f_cred, vp); 1735 VOP_UNLOCK(vp); 1736 if (error != 0) 1737 return (error); 1738 } 1739 #endif 1740 error = VOP_POLL(vp, events, fp->f_cred, td); 1741 return (error); 1742 } 1743 1744 /* 1745 * Acquire the requested lock and then check for validity. LK_RETRY 1746 * permits vn_lock to return doomed vnodes. 1747 */ 1748 static int __noinline 1749 _vn_lock_fallback(struct vnode *vp, int flags, const char *file, int line, 1750 int error) 1751 { 1752 1753 KASSERT((flags & LK_RETRY) == 0 || error == 0, 1754 ("vn_lock: error %d incompatible with flags %#x", error, flags)); 1755 1756 if (error == 0) 1757 VNASSERT(VN_IS_DOOMED(vp), vp, ("vnode not doomed")); 1758 1759 if ((flags & LK_RETRY) == 0) { 1760 if (error == 0) { 1761 VOP_UNLOCK(vp); 1762 error = ENOENT; 1763 } 1764 return (error); 1765 } 1766 1767 /* 1768 * LK_RETRY case. 1769 * 1770 * Nothing to do if we got the lock. 1771 */ 1772 if (error == 0) 1773 return (0); 1774 1775 /* 1776 * Interlock was dropped by the call in _vn_lock. 1777 */ 1778 flags &= ~LK_INTERLOCK; 1779 do { 1780 error = VOP_LOCK1(vp, flags, file, line); 1781 } while (error != 0); 1782 return (0); 1783 } 1784 1785 int 1786 _vn_lock(struct vnode *vp, int flags, const char *file, int line) 1787 { 1788 int error; 1789 1790 VNASSERT((flags & LK_TYPE_MASK) != 0, vp, 1791 ("vn_lock: no locktype (%d passed)", flags)); 1792 VNPASS(vp->v_holdcnt > 0, vp); 1793 error = VOP_LOCK1(vp, flags, file, line); 1794 if (__predict_false(error != 0 || VN_IS_DOOMED(vp))) 1795 return (_vn_lock_fallback(vp, flags, file, line, error)); 1796 return (0); 1797 } 1798 1799 /* 1800 * File table vnode close routine. 1801 */ 1802 static int 1803 vn_closefile(struct file *fp, struct thread *td) 1804 { 1805 struct vnode *vp; 1806 struct flock lf; 1807 int error; 1808 bool ref; 1809 1810 vp = fp->f_vnode; 1811 fp->f_ops = &badfileops; 1812 ref = (fp->f_flag & FHASLOCK) != 0 && fp->f_type == DTYPE_VNODE; 1813 1814 error = vn_close1(vp, fp->f_flag, fp->f_cred, td, ref); 1815 1816 if (__predict_false(ref)) { 1817 lf.l_whence = SEEK_SET; 1818 lf.l_start = 0; 1819 lf.l_len = 0; 1820 lf.l_type = F_UNLCK; 1821 (void) VOP_ADVLOCK(vp, fp, F_UNLCK, &lf, F_FLOCK); 1822 vrele(vp); 1823 } 1824 return (error); 1825 } 1826 1827 /* 1828 * Preparing to start a filesystem write operation. If the operation is 1829 * permitted, then we bump the count of operations in progress and 1830 * proceed. If a suspend request is in progress, we wait until the 1831 * suspension is over, and then proceed. 1832 */ 1833 static int 1834 vn_start_write_refed(struct mount *mp, int flags, bool mplocked) 1835 { 1836 struct mount_pcpu *mpcpu; 1837 int error, mflags; 1838 1839 if (__predict_true(!mplocked) && (flags & V_XSLEEP) == 0 && 1840 vfs_op_thread_enter(mp, mpcpu)) { 1841 MPASS((mp->mnt_kern_flag & MNTK_SUSPEND) == 0); 1842 vfs_mp_count_add_pcpu(mpcpu, writeopcount, 1); 1843 vfs_op_thread_exit(mp, mpcpu); 1844 return (0); 1845 } 1846 1847 if (mplocked) 1848 mtx_assert(MNT_MTX(mp), MA_OWNED); 1849 else 1850 MNT_ILOCK(mp); 1851 1852 error = 0; 1853 1854 /* 1855 * Check on status of suspension. 1856 */ 1857 if ((curthread->td_pflags & TDP_IGNSUSP) == 0 || 1858 mp->mnt_susp_owner != curthread) { 1859 mflags = ((mp->mnt_vfc->vfc_flags & VFCF_SBDRY) != 0 ? 1860 (flags & PCATCH) : 0) | (PUSER - 1); 1861 while ((mp->mnt_kern_flag & MNTK_SUSPEND) != 0) { 1862 if (flags & V_NOWAIT) { 1863 error = EWOULDBLOCK; 1864 goto unlock; 1865 } 1866 error = msleep(&mp->mnt_flag, MNT_MTX(mp), mflags, 1867 "suspfs", 0); 1868 if (error) 1869 goto unlock; 1870 } 1871 } 1872 if (flags & V_XSLEEP) 1873 goto unlock; 1874 mp->mnt_writeopcount++; 1875 unlock: 1876 if (error != 0 || (flags & V_XSLEEP) != 0) 1877 MNT_REL(mp); 1878 MNT_IUNLOCK(mp); 1879 return (error); 1880 } 1881 1882 int 1883 vn_start_write(struct vnode *vp, struct mount **mpp, int flags) 1884 { 1885 struct mount *mp; 1886 int error; 1887 1888 KASSERT((flags & V_MNTREF) == 0 || (*mpp != NULL && vp == NULL), 1889 ("V_MNTREF requires mp")); 1890 1891 error = 0; 1892 /* 1893 * If a vnode is provided, get and return the mount point that 1894 * to which it will write. 1895 */ 1896 if (vp != NULL) { 1897 if ((error = VOP_GETWRITEMOUNT(vp, mpp)) != 0) { 1898 *mpp = NULL; 1899 if (error != EOPNOTSUPP) 1900 return (error); 1901 return (0); 1902 } 1903 } 1904 if ((mp = *mpp) == NULL) 1905 return (0); 1906 1907 /* 1908 * VOP_GETWRITEMOUNT() returns with the mp refcount held through 1909 * a vfs_ref(). 1910 * As long as a vnode is not provided we need to acquire a 1911 * refcount for the provided mountpoint too, in order to 1912 * emulate a vfs_ref(). 1913 */ 1914 if (vp == NULL && (flags & V_MNTREF) == 0) 1915 vfs_ref(mp); 1916 1917 return (vn_start_write_refed(mp, flags, false)); 1918 } 1919 1920 /* 1921 * Secondary suspension. Used by operations such as vop_inactive 1922 * routines that are needed by the higher level functions. These 1923 * are allowed to proceed until all the higher level functions have 1924 * completed (indicated by mnt_writeopcount dropping to zero). At that 1925 * time, these operations are halted until the suspension is over. 1926 */ 1927 int 1928 vn_start_secondary_write(struct vnode *vp, struct mount **mpp, int flags) 1929 { 1930 struct mount *mp; 1931 int error; 1932 1933 KASSERT((flags & V_MNTREF) == 0 || (*mpp != NULL && vp == NULL), 1934 ("V_MNTREF requires mp")); 1935 1936 retry: 1937 if (vp != NULL) { 1938 if ((error = VOP_GETWRITEMOUNT(vp, mpp)) != 0) { 1939 *mpp = NULL; 1940 if (error != EOPNOTSUPP) 1941 return (error); 1942 return (0); 1943 } 1944 } 1945 /* 1946 * If we are not suspended or have not yet reached suspended 1947 * mode, then let the operation proceed. 1948 */ 1949 if ((mp = *mpp) == NULL) 1950 return (0); 1951 1952 /* 1953 * VOP_GETWRITEMOUNT() returns with the mp refcount held through 1954 * a vfs_ref(). 1955 * As long as a vnode is not provided we need to acquire a 1956 * refcount for the provided mountpoint too, in order to 1957 * emulate a vfs_ref(). 1958 */ 1959 MNT_ILOCK(mp); 1960 if (vp == NULL && (flags & V_MNTREF) == 0) 1961 MNT_REF(mp); 1962 if ((mp->mnt_kern_flag & (MNTK_SUSPENDED | MNTK_SUSPEND2)) == 0) { 1963 mp->mnt_secondary_writes++; 1964 mp->mnt_secondary_accwrites++; 1965 MNT_IUNLOCK(mp); 1966 return (0); 1967 } 1968 if (flags & V_NOWAIT) { 1969 MNT_REL(mp); 1970 MNT_IUNLOCK(mp); 1971 return (EWOULDBLOCK); 1972 } 1973 /* 1974 * Wait for the suspension to finish. 1975 */ 1976 error = msleep(&mp->mnt_flag, MNT_MTX(mp), (PUSER - 1) | PDROP | 1977 ((mp->mnt_vfc->vfc_flags & VFCF_SBDRY) != 0 ? (flags & PCATCH) : 0), 1978 "suspfs", 0); 1979 vfs_rel(mp); 1980 if (error == 0) 1981 goto retry; 1982 return (error); 1983 } 1984 1985 /* 1986 * Filesystem write operation has completed. If we are suspending and this 1987 * operation is the last one, notify the suspender that the suspension is 1988 * now in effect. 1989 */ 1990 void 1991 vn_finished_write(struct mount *mp) 1992 { 1993 struct mount_pcpu *mpcpu; 1994 int c; 1995 1996 if (mp == NULL) 1997 return; 1998 1999 if (vfs_op_thread_enter(mp, mpcpu)) { 2000 vfs_mp_count_sub_pcpu(mpcpu, writeopcount, 1); 2001 vfs_mp_count_sub_pcpu(mpcpu, ref, 1); 2002 vfs_op_thread_exit(mp, mpcpu); 2003 return; 2004 } 2005 2006 MNT_ILOCK(mp); 2007 vfs_assert_mount_counters(mp); 2008 MNT_REL(mp); 2009 c = --mp->mnt_writeopcount; 2010 if (mp->mnt_vfs_ops == 0) { 2011 MPASS((mp->mnt_kern_flag & MNTK_SUSPEND) == 0); 2012 MNT_IUNLOCK(mp); 2013 return; 2014 } 2015 if (c < 0) 2016 vfs_dump_mount_counters(mp); 2017 if ((mp->mnt_kern_flag & MNTK_SUSPEND) != 0 && c == 0) 2018 wakeup(&mp->mnt_writeopcount); 2019 MNT_IUNLOCK(mp); 2020 } 2021 2022 /* 2023 * Filesystem secondary write operation has completed. If we are 2024 * suspending and this operation is the last one, notify the suspender 2025 * that the suspension is now in effect. 2026 */ 2027 void 2028 vn_finished_secondary_write(struct mount *mp) 2029 { 2030 if (mp == NULL) 2031 return; 2032 MNT_ILOCK(mp); 2033 MNT_REL(mp); 2034 mp->mnt_secondary_writes--; 2035 if (mp->mnt_secondary_writes < 0) 2036 panic("vn_finished_secondary_write: neg cnt"); 2037 if ((mp->mnt_kern_flag & MNTK_SUSPEND) != 0 && 2038 mp->mnt_secondary_writes <= 0) 2039 wakeup(&mp->mnt_secondary_writes); 2040 MNT_IUNLOCK(mp); 2041 } 2042 2043 /* 2044 * Request a filesystem to suspend write operations. 2045 */ 2046 int 2047 vfs_write_suspend(struct mount *mp, int flags) 2048 { 2049 int error; 2050 2051 vfs_op_enter(mp); 2052 2053 MNT_ILOCK(mp); 2054 vfs_assert_mount_counters(mp); 2055 if (mp->mnt_susp_owner == curthread) { 2056 vfs_op_exit_locked(mp); 2057 MNT_IUNLOCK(mp); 2058 return (EALREADY); 2059 } 2060 while (mp->mnt_kern_flag & MNTK_SUSPEND) 2061 msleep(&mp->mnt_flag, MNT_MTX(mp), PUSER - 1, "wsuspfs", 0); 2062 2063 /* 2064 * Unmount holds a write reference on the mount point. If we 2065 * own busy reference and drain for writers, we deadlock with 2066 * the reference draining in the unmount path. Callers of 2067 * vfs_write_suspend() must specify VS_SKIP_UNMOUNT if 2068 * vfs_busy() reference is owned and caller is not in the 2069 * unmount context. 2070 */ 2071 if ((flags & VS_SKIP_UNMOUNT) != 0 && 2072 (mp->mnt_kern_flag & MNTK_UNMOUNT) != 0) { 2073 vfs_op_exit_locked(mp); 2074 MNT_IUNLOCK(mp); 2075 return (EBUSY); 2076 } 2077 2078 mp->mnt_kern_flag |= MNTK_SUSPEND; 2079 mp->mnt_susp_owner = curthread; 2080 if (mp->mnt_writeopcount > 0) 2081 (void) msleep(&mp->mnt_writeopcount, 2082 MNT_MTX(mp), (PUSER - 1)|PDROP, "suspwt", 0); 2083 else 2084 MNT_IUNLOCK(mp); 2085 if ((error = VFS_SYNC(mp, MNT_SUSPEND)) != 0) { 2086 vfs_write_resume(mp, 0); 2087 /* vfs_write_resume does vfs_op_exit() for us */ 2088 } 2089 return (error); 2090 } 2091 2092 /* 2093 * Request a filesystem to resume write operations. 2094 */ 2095 void 2096 vfs_write_resume(struct mount *mp, int flags) 2097 { 2098 2099 MNT_ILOCK(mp); 2100 if ((mp->mnt_kern_flag & MNTK_SUSPEND) != 0) { 2101 KASSERT(mp->mnt_susp_owner == curthread, ("mnt_susp_owner")); 2102 mp->mnt_kern_flag &= ~(MNTK_SUSPEND | MNTK_SUSPEND2 | 2103 MNTK_SUSPENDED); 2104 mp->mnt_susp_owner = NULL; 2105 wakeup(&mp->mnt_writeopcount); 2106 wakeup(&mp->mnt_flag); 2107 curthread->td_pflags &= ~TDP_IGNSUSP; 2108 if ((flags & VR_START_WRITE) != 0) { 2109 MNT_REF(mp); 2110 mp->mnt_writeopcount++; 2111 } 2112 MNT_IUNLOCK(mp); 2113 if ((flags & VR_NO_SUSPCLR) == 0) 2114 VFS_SUSP_CLEAN(mp); 2115 vfs_op_exit(mp); 2116 } else if ((flags & VR_START_WRITE) != 0) { 2117 MNT_REF(mp); 2118 vn_start_write_refed(mp, 0, true); 2119 } else { 2120 MNT_IUNLOCK(mp); 2121 } 2122 } 2123 2124 /* 2125 * Helper loop around vfs_write_suspend() for filesystem unmount VFS 2126 * methods. 2127 */ 2128 int 2129 vfs_write_suspend_umnt(struct mount *mp) 2130 { 2131 int error; 2132 2133 KASSERT((curthread->td_pflags & TDP_IGNSUSP) == 0, 2134 ("vfs_write_suspend_umnt: recursed")); 2135 2136 /* dounmount() already called vn_start_write(). */ 2137 for (;;) { 2138 vn_finished_write(mp); 2139 error = vfs_write_suspend(mp, 0); 2140 if (error != 0) { 2141 vn_start_write(NULL, &mp, V_WAIT); 2142 return (error); 2143 } 2144 MNT_ILOCK(mp); 2145 if ((mp->mnt_kern_flag & MNTK_SUSPENDED) != 0) 2146 break; 2147 MNT_IUNLOCK(mp); 2148 vn_start_write(NULL, &mp, V_WAIT); 2149 } 2150 mp->mnt_kern_flag &= ~(MNTK_SUSPENDED | MNTK_SUSPEND2); 2151 wakeup(&mp->mnt_flag); 2152 MNT_IUNLOCK(mp); 2153 curthread->td_pflags |= TDP_IGNSUSP; 2154 return (0); 2155 } 2156 2157 /* 2158 * Implement kqueues for files by translating it to vnode operation. 2159 */ 2160 static int 2161 vn_kqfilter(struct file *fp, struct knote *kn) 2162 { 2163 2164 return (VOP_KQFILTER(fp->f_vnode, kn)); 2165 } 2166 2167 int 2168 vn_kqfilter_opath(struct file *fp, struct knote *kn) 2169 { 2170 if ((fp->f_flag & FKQALLOWED) == 0) 2171 return (EBADF); 2172 return (vn_kqfilter(fp, kn)); 2173 } 2174 2175 /* 2176 * Simplified in-kernel wrapper calls for extended attribute access. 2177 * Both calls pass in a NULL credential, authorizing as "kernel" access. 2178 * Set IO_NODELOCKED in ioflg if the vnode is already locked. 2179 */ 2180 int 2181 vn_extattr_get(struct vnode *vp, int ioflg, int attrnamespace, 2182 const char *attrname, int *buflen, char *buf, struct thread *td) 2183 { 2184 struct uio auio; 2185 struct iovec iov; 2186 int error; 2187 2188 iov.iov_len = *buflen; 2189 iov.iov_base = buf; 2190 2191 auio.uio_iov = &iov; 2192 auio.uio_iovcnt = 1; 2193 auio.uio_rw = UIO_READ; 2194 auio.uio_segflg = UIO_SYSSPACE; 2195 auio.uio_td = td; 2196 auio.uio_offset = 0; 2197 auio.uio_resid = *buflen; 2198 2199 if ((ioflg & IO_NODELOCKED) == 0) 2200 vn_lock(vp, LK_SHARED | LK_RETRY); 2201 2202 ASSERT_VOP_LOCKED(vp, "IO_NODELOCKED with no vp lock held"); 2203 2204 /* authorize attribute retrieval as kernel */ 2205 error = VOP_GETEXTATTR(vp, attrnamespace, attrname, &auio, NULL, NULL, 2206 td); 2207 2208 if ((ioflg & IO_NODELOCKED) == 0) 2209 VOP_UNLOCK(vp); 2210 2211 if (error == 0) { 2212 *buflen = *buflen - auio.uio_resid; 2213 } 2214 2215 return (error); 2216 } 2217 2218 /* 2219 * XXX failure mode if partially written? 2220 */ 2221 int 2222 vn_extattr_set(struct vnode *vp, int ioflg, int attrnamespace, 2223 const char *attrname, int buflen, char *buf, struct thread *td) 2224 { 2225 struct uio auio; 2226 struct iovec iov; 2227 struct mount *mp; 2228 int error; 2229 2230 iov.iov_len = buflen; 2231 iov.iov_base = buf; 2232 2233 auio.uio_iov = &iov; 2234 auio.uio_iovcnt = 1; 2235 auio.uio_rw = UIO_WRITE; 2236 auio.uio_segflg = UIO_SYSSPACE; 2237 auio.uio_td = td; 2238 auio.uio_offset = 0; 2239 auio.uio_resid = buflen; 2240 2241 if ((ioflg & IO_NODELOCKED) == 0) { 2242 if ((error = vn_start_write(vp, &mp, V_WAIT)) != 0) 2243 return (error); 2244 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 2245 } 2246 2247 ASSERT_VOP_LOCKED(vp, "IO_NODELOCKED with no vp lock held"); 2248 2249 /* authorize attribute setting as kernel */ 2250 error = VOP_SETEXTATTR(vp, attrnamespace, attrname, &auio, NULL, td); 2251 2252 if ((ioflg & IO_NODELOCKED) == 0) { 2253 vn_finished_write(mp); 2254 VOP_UNLOCK(vp); 2255 } 2256 2257 return (error); 2258 } 2259 2260 int 2261 vn_extattr_rm(struct vnode *vp, int ioflg, int attrnamespace, 2262 const char *attrname, struct thread *td) 2263 { 2264 struct mount *mp; 2265 int error; 2266 2267 if ((ioflg & IO_NODELOCKED) == 0) { 2268 if ((error = vn_start_write(vp, &mp, V_WAIT)) != 0) 2269 return (error); 2270 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 2271 } 2272 2273 ASSERT_VOP_LOCKED(vp, "IO_NODELOCKED with no vp lock held"); 2274 2275 /* authorize attribute removal as kernel */ 2276 error = VOP_DELETEEXTATTR(vp, attrnamespace, attrname, NULL, td); 2277 if (error == EOPNOTSUPP) 2278 error = VOP_SETEXTATTR(vp, attrnamespace, attrname, NULL, 2279 NULL, td); 2280 2281 if ((ioflg & IO_NODELOCKED) == 0) { 2282 vn_finished_write(mp); 2283 VOP_UNLOCK(vp); 2284 } 2285 2286 return (error); 2287 } 2288 2289 static int 2290 vn_get_ino_alloc_vget(struct mount *mp, void *arg, int lkflags, 2291 struct vnode **rvp) 2292 { 2293 2294 return (VFS_VGET(mp, *(ino_t *)arg, lkflags, rvp)); 2295 } 2296 2297 int 2298 vn_vget_ino(struct vnode *vp, ino_t ino, int lkflags, struct vnode **rvp) 2299 { 2300 2301 return (vn_vget_ino_gen(vp, vn_get_ino_alloc_vget, &ino, 2302 lkflags, rvp)); 2303 } 2304 2305 int 2306 vn_vget_ino_gen(struct vnode *vp, vn_get_ino_t alloc, void *alloc_arg, 2307 int lkflags, struct vnode **rvp) 2308 { 2309 struct mount *mp; 2310 int ltype, error; 2311 2312 ASSERT_VOP_LOCKED(vp, "vn_vget_ino_get"); 2313 mp = vp->v_mount; 2314 ltype = VOP_ISLOCKED(vp); 2315 KASSERT(ltype == LK_EXCLUSIVE || ltype == LK_SHARED, 2316 ("vn_vget_ino: vp not locked")); 2317 error = vfs_busy(mp, MBF_NOWAIT); 2318 if (error != 0) { 2319 vfs_ref(mp); 2320 VOP_UNLOCK(vp); 2321 error = vfs_busy(mp, 0); 2322 vn_lock(vp, ltype | LK_RETRY); 2323 vfs_rel(mp); 2324 if (error != 0) 2325 return (ENOENT); 2326 if (VN_IS_DOOMED(vp)) { 2327 vfs_unbusy(mp); 2328 return (ENOENT); 2329 } 2330 } 2331 VOP_UNLOCK(vp); 2332 error = alloc(mp, alloc_arg, lkflags, rvp); 2333 vfs_unbusy(mp); 2334 if (error != 0 || *rvp != vp) 2335 vn_lock(vp, ltype | LK_RETRY); 2336 if (VN_IS_DOOMED(vp)) { 2337 if (error == 0) { 2338 if (*rvp == vp) 2339 vunref(vp); 2340 else 2341 vput(*rvp); 2342 } 2343 error = ENOENT; 2344 } 2345 return (error); 2346 } 2347 2348 int 2349 vn_rlimit_fsize(const struct vnode *vp, const struct uio *uio, 2350 struct thread *td) 2351 { 2352 2353 if (vp->v_type != VREG || td == NULL) 2354 return (0); 2355 if ((uoff_t)uio->uio_offset + uio->uio_resid > 2356 lim_cur(td, RLIMIT_FSIZE)) { 2357 PROC_LOCK(td->td_proc); 2358 kern_psignal(td->td_proc, SIGXFSZ); 2359 PROC_UNLOCK(td->td_proc); 2360 return (EFBIG); 2361 } 2362 return (0); 2363 } 2364 2365 int 2366 vn_chmod(struct file *fp, mode_t mode, struct ucred *active_cred, 2367 struct thread *td) 2368 { 2369 struct vnode *vp; 2370 2371 vp = fp->f_vnode; 2372 #ifdef AUDIT 2373 vn_lock(vp, LK_SHARED | LK_RETRY); 2374 AUDIT_ARG_VNODE1(vp); 2375 VOP_UNLOCK(vp); 2376 #endif 2377 return (setfmode(td, active_cred, vp, mode)); 2378 } 2379 2380 int 2381 vn_chown(struct file *fp, uid_t uid, gid_t gid, struct ucred *active_cred, 2382 struct thread *td) 2383 { 2384 struct vnode *vp; 2385 2386 vp = fp->f_vnode; 2387 #ifdef AUDIT 2388 vn_lock(vp, LK_SHARED | LK_RETRY); 2389 AUDIT_ARG_VNODE1(vp); 2390 VOP_UNLOCK(vp); 2391 #endif 2392 return (setfown(td, active_cred, vp, uid, gid)); 2393 } 2394 2395 void 2396 vn_pages_remove(struct vnode *vp, vm_pindex_t start, vm_pindex_t end) 2397 { 2398 vm_object_t object; 2399 2400 if ((object = vp->v_object) == NULL) 2401 return; 2402 VM_OBJECT_WLOCK(object); 2403 vm_object_page_remove(object, start, end, 0); 2404 VM_OBJECT_WUNLOCK(object); 2405 } 2406 2407 int 2408 vn_bmap_seekhole(struct vnode *vp, u_long cmd, off_t *off, struct ucred *cred) 2409 { 2410 struct vattr va; 2411 daddr_t bn, bnp; 2412 uint64_t bsize; 2413 off_t noff; 2414 int error; 2415 2416 KASSERT(cmd == FIOSEEKHOLE || cmd == FIOSEEKDATA, 2417 ("Wrong command %lu", cmd)); 2418 2419 if (vn_lock(vp, LK_SHARED) != 0) 2420 return (EBADF); 2421 if (vp->v_type != VREG) { 2422 error = ENOTTY; 2423 goto unlock; 2424 } 2425 error = VOP_GETATTR(vp, &va, cred); 2426 if (error != 0) 2427 goto unlock; 2428 noff = *off; 2429 if (noff >= va.va_size) { 2430 error = ENXIO; 2431 goto unlock; 2432 } 2433 bsize = vp->v_mount->mnt_stat.f_iosize; 2434 for (bn = noff / bsize; noff < va.va_size; bn++, noff += bsize - 2435 noff % bsize) { 2436 error = VOP_BMAP(vp, bn, NULL, &bnp, NULL, NULL); 2437 if (error == EOPNOTSUPP) { 2438 error = ENOTTY; 2439 goto unlock; 2440 } 2441 if ((bnp == -1 && cmd == FIOSEEKHOLE) || 2442 (bnp != -1 && cmd == FIOSEEKDATA)) { 2443 noff = bn * bsize; 2444 if (noff < *off) 2445 noff = *off; 2446 goto unlock; 2447 } 2448 } 2449 if (noff > va.va_size) 2450 noff = va.va_size; 2451 /* noff == va.va_size. There is an implicit hole at the end of file. */ 2452 if (cmd == FIOSEEKDATA) 2453 error = ENXIO; 2454 unlock: 2455 VOP_UNLOCK(vp); 2456 if (error == 0) 2457 *off = noff; 2458 return (error); 2459 } 2460 2461 int 2462 vn_seek(struct file *fp, off_t offset, int whence, struct thread *td) 2463 { 2464 struct ucred *cred; 2465 struct vnode *vp; 2466 struct vattr vattr; 2467 off_t foffset, size; 2468 int error, noneg; 2469 2470 cred = td->td_ucred; 2471 vp = fp->f_vnode; 2472 foffset = foffset_lock(fp, 0); 2473 noneg = (vp->v_type != VCHR); 2474 error = 0; 2475 switch (whence) { 2476 case L_INCR: 2477 if (noneg && 2478 (foffset < 0 || 2479 (offset > 0 && foffset > OFF_MAX - offset))) { 2480 error = EOVERFLOW; 2481 break; 2482 } 2483 offset += foffset; 2484 break; 2485 case L_XTND: 2486 vn_lock(vp, LK_SHARED | LK_RETRY); 2487 error = VOP_GETATTR(vp, &vattr, cred); 2488 VOP_UNLOCK(vp); 2489 if (error) 2490 break; 2491 2492 /* 2493 * If the file references a disk device, then fetch 2494 * the media size and use that to determine the ending 2495 * offset. 2496 */ 2497 if (vattr.va_size == 0 && vp->v_type == VCHR && 2498 fo_ioctl(fp, DIOCGMEDIASIZE, &size, cred, td) == 0) 2499 vattr.va_size = size; 2500 if (noneg && 2501 (vattr.va_size > OFF_MAX || 2502 (offset > 0 && vattr.va_size > OFF_MAX - offset))) { 2503 error = EOVERFLOW; 2504 break; 2505 } 2506 offset += vattr.va_size; 2507 break; 2508 case L_SET: 2509 break; 2510 case SEEK_DATA: 2511 error = fo_ioctl(fp, FIOSEEKDATA, &offset, cred, td); 2512 if (error == ENOTTY) 2513 error = EINVAL; 2514 break; 2515 case SEEK_HOLE: 2516 error = fo_ioctl(fp, FIOSEEKHOLE, &offset, cred, td); 2517 if (error == ENOTTY) 2518 error = EINVAL; 2519 break; 2520 default: 2521 error = EINVAL; 2522 } 2523 if (error == 0 && noneg && offset < 0) 2524 error = EINVAL; 2525 if (error != 0) 2526 goto drop; 2527 VFS_KNOTE_UNLOCKED(vp, 0); 2528 td->td_uretoff.tdu_off = offset; 2529 drop: 2530 foffset_unlock(fp, offset, error != 0 ? FOF_NOUPDATE : 0); 2531 return (error); 2532 } 2533 2534 int 2535 vn_utimes_perm(struct vnode *vp, struct vattr *vap, struct ucred *cred, 2536 struct thread *td) 2537 { 2538 int error; 2539 2540 /* 2541 * Grant permission if the caller is the owner of the file, or 2542 * the super-user, or has ACL_WRITE_ATTRIBUTES permission on 2543 * on the file. If the time pointer is null, then write 2544 * permission on the file is also sufficient. 2545 * 2546 * From NFSv4.1, draft 21, 6.2.1.3.1, Discussion of Mask Attributes: 2547 * A user having ACL_WRITE_DATA or ACL_WRITE_ATTRIBUTES 2548 * will be allowed to set the times [..] to the current 2549 * server time. 2550 */ 2551 error = VOP_ACCESSX(vp, VWRITE_ATTRIBUTES, cred, td); 2552 if (error != 0 && (vap->va_vaflags & VA_UTIMES_NULL) != 0) 2553 error = VOP_ACCESS(vp, VWRITE, cred, td); 2554 return (error); 2555 } 2556 2557 int 2558 vn_fill_kinfo(struct file *fp, struct kinfo_file *kif, struct filedesc *fdp) 2559 { 2560 struct vnode *vp; 2561 int error; 2562 2563 if (fp->f_type == DTYPE_FIFO) 2564 kif->kf_type = KF_TYPE_FIFO; 2565 else 2566 kif->kf_type = KF_TYPE_VNODE; 2567 vp = fp->f_vnode; 2568 vref(vp); 2569 FILEDESC_SUNLOCK(fdp); 2570 error = vn_fill_kinfo_vnode(vp, kif); 2571 vrele(vp); 2572 FILEDESC_SLOCK(fdp); 2573 return (error); 2574 } 2575 2576 static inline void 2577 vn_fill_junk(struct kinfo_file *kif) 2578 { 2579 size_t len, olen; 2580 2581 /* 2582 * Simulate vn_fullpath returning changing values for a given 2583 * vp during e.g. coredump. 2584 */ 2585 len = (arc4random() % (sizeof(kif->kf_path) - 2)) + 1; 2586 olen = strlen(kif->kf_path); 2587 if (len < olen) 2588 strcpy(&kif->kf_path[len - 1], "$"); 2589 else 2590 for (; olen < len; olen++) 2591 strcpy(&kif->kf_path[olen], "A"); 2592 } 2593 2594 int 2595 vn_fill_kinfo_vnode(struct vnode *vp, struct kinfo_file *kif) 2596 { 2597 struct vattr va; 2598 char *fullpath, *freepath; 2599 int error; 2600 2601 kif->kf_un.kf_file.kf_file_type = vntype_to_kinfo(vp->v_type); 2602 freepath = NULL; 2603 fullpath = "-"; 2604 error = vn_fullpath(vp, &fullpath, &freepath); 2605 if (error == 0) { 2606 strlcpy(kif->kf_path, fullpath, sizeof(kif->kf_path)); 2607 } 2608 if (freepath != NULL) 2609 free(freepath, M_TEMP); 2610 2611 KFAIL_POINT_CODE(DEBUG_FP, fill_kinfo_vnode__random_path, 2612 vn_fill_junk(kif); 2613 ); 2614 2615 /* 2616 * Retrieve vnode attributes. 2617 */ 2618 va.va_fsid = VNOVAL; 2619 va.va_rdev = NODEV; 2620 vn_lock(vp, LK_SHARED | LK_RETRY); 2621 error = VOP_GETATTR(vp, &va, curthread->td_ucred); 2622 VOP_UNLOCK(vp); 2623 if (error != 0) 2624 return (error); 2625 if (va.va_fsid != VNOVAL) 2626 kif->kf_un.kf_file.kf_file_fsid = va.va_fsid; 2627 else 2628 kif->kf_un.kf_file.kf_file_fsid = 2629 vp->v_mount->mnt_stat.f_fsid.val[0]; 2630 kif->kf_un.kf_file.kf_file_fsid_freebsd11 = 2631 kif->kf_un.kf_file.kf_file_fsid; /* truncate */ 2632 kif->kf_un.kf_file.kf_file_fileid = va.va_fileid; 2633 kif->kf_un.kf_file.kf_file_mode = MAKEIMODE(va.va_type, va.va_mode); 2634 kif->kf_un.kf_file.kf_file_size = va.va_size; 2635 kif->kf_un.kf_file.kf_file_rdev = va.va_rdev; 2636 kif->kf_un.kf_file.kf_file_rdev_freebsd11 = 2637 kif->kf_un.kf_file.kf_file_rdev; /* truncate */ 2638 return (0); 2639 } 2640 2641 int 2642 vn_mmap(struct file *fp, vm_map_t map, vm_offset_t *addr, vm_size_t size, 2643 vm_prot_t prot, vm_prot_t cap_maxprot, int flags, vm_ooffset_t foff, 2644 struct thread *td) 2645 { 2646 #ifdef HWPMC_HOOKS 2647 struct pmckern_map_in pkm; 2648 #endif 2649 struct mount *mp; 2650 struct vnode *vp; 2651 vm_object_t object; 2652 vm_prot_t maxprot; 2653 boolean_t writecounted; 2654 int error; 2655 2656 #if defined(COMPAT_FREEBSD7) || defined(COMPAT_FREEBSD6) || \ 2657 defined(COMPAT_FREEBSD5) || defined(COMPAT_FREEBSD4) 2658 /* 2659 * POSIX shared-memory objects are defined to have 2660 * kernel persistence, and are not defined to support 2661 * read(2)/write(2) -- or even open(2). Thus, we can 2662 * use MAP_ASYNC to trade on-disk coherence for speed. 2663 * The shm_open(3) library routine turns on the FPOSIXSHM 2664 * flag to request this behavior. 2665 */ 2666 if ((fp->f_flag & FPOSIXSHM) != 0) 2667 flags |= MAP_NOSYNC; 2668 #endif 2669 vp = fp->f_vnode; 2670 2671 /* 2672 * Ensure that file and memory protections are 2673 * compatible. Note that we only worry about 2674 * writability if mapping is shared; in this case, 2675 * current and max prot are dictated by the open file. 2676 * XXX use the vnode instead? Problem is: what 2677 * credentials do we use for determination? What if 2678 * proc does a setuid? 2679 */ 2680 mp = vp->v_mount; 2681 if (mp != NULL && (mp->mnt_flag & MNT_NOEXEC) != 0) { 2682 maxprot = VM_PROT_NONE; 2683 if ((prot & VM_PROT_EXECUTE) != 0) 2684 return (EACCES); 2685 } else 2686 maxprot = VM_PROT_EXECUTE; 2687 if ((fp->f_flag & FREAD) != 0) 2688 maxprot |= VM_PROT_READ; 2689 else if ((prot & VM_PROT_READ) != 0) 2690 return (EACCES); 2691 2692 /* 2693 * If we are sharing potential changes via MAP_SHARED and we 2694 * are trying to get write permission although we opened it 2695 * without asking for it, bail out. 2696 */ 2697 if ((flags & MAP_SHARED) != 0) { 2698 if ((fp->f_flag & FWRITE) != 0) 2699 maxprot |= VM_PROT_WRITE; 2700 else if ((prot & VM_PROT_WRITE) != 0) 2701 return (EACCES); 2702 } else { 2703 maxprot |= VM_PROT_WRITE; 2704 cap_maxprot |= VM_PROT_WRITE; 2705 } 2706 maxprot &= cap_maxprot; 2707 2708 /* 2709 * For regular files and shared memory, POSIX requires that 2710 * the value of foff be a legitimate offset within the data 2711 * object. In particular, negative offsets are invalid. 2712 * Blocking negative offsets and overflows here avoids 2713 * possible wraparound or user-level access into reserved 2714 * ranges of the data object later. In contrast, POSIX does 2715 * not dictate how offsets are used by device drivers, so in 2716 * the case of a device mapping a negative offset is passed 2717 * on. 2718 */ 2719 if ( 2720 #ifdef _LP64 2721 size > OFF_MAX || 2722 #endif 2723 foff > OFF_MAX - size) 2724 return (EINVAL); 2725 2726 writecounted = FALSE; 2727 error = vm_mmap_vnode(td, size, prot, &maxprot, &flags, vp, 2728 &foff, &object, &writecounted); 2729 if (error != 0) 2730 return (error); 2731 error = vm_mmap_object(map, addr, size, prot, maxprot, flags, object, 2732 foff, writecounted, td); 2733 if (error != 0) { 2734 /* 2735 * If this mapping was accounted for in the vnode's 2736 * writecount, then undo that now. 2737 */ 2738 if (writecounted) 2739 vm_pager_release_writecount(object, 0, size); 2740 vm_object_deallocate(object); 2741 } 2742 #ifdef HWPMC_HOOKS 2743 /* Inform hwpmc(4) if an executable is being mapped. */ 2744 if (PMC_HOOK_INSTALLED(PMC_FN_MMAP)) { 2745 if ((prot & VM_PROT_EXECUTE) != 0 && error == 0) { 2746 pkm.pm_file = vp; 2747 pkm.pm_address = (uintptr_t) *addr; 2748 PMC_CALL_HOOK_UNLOCKED(td, PMC_FN_MMAP, (void *) &pkm); 2749 } 2750 } 2751 #endif 2752 return (error); 2753 } 2754 2755 void 2756 vn_fsid(struct vnode *vp, struct vattr *va) 2757 { 2758 fsid_t *f; 2759 2760 f = &vp->v_mount->mnt_stat.f_fsid; 2761 va->va_fsid = (uint32_t)f->val[1]; 2762 va->va_fsid <<= sizeof(f->val[1]) * NBBY; 2763 va->va_fsid += (uint32_t)f->val[0]; 2764 } 2765 2766 int 2767 vn_fsync_buf(struct vnode *vp, int waitfor) 2768 { 2769 struct buf *bp, *nbp; 2770 struct bufobj *bo; 2771 struct mount *mp; 2772 int error, maxretry; 2773 2774 error = 0; 2775 maxretry = 10000; /* large, arbitrarily chosen */ 2776 mp = NULL; 2777 if (vp->v_type == VCHR) { 2778 VI_LOCK(vp); 2779 mp = vp->v_rdev->si_mountpt; 2780 VI_UNLOCK(vp); 2781 } 2782 bo = &vp->v_bufobj; 2783 BO_LOCK(bo); 2784 loop1: 2785 /* 2786 * MARK/SCAN initialization to avoid infinite loops. 2787 */ 2788 TAILQ_FOREACH(bp, &bo->bo_dirty.bv_hd, b_bobufs) { 2789 bp->b_vflags &= ~BV_SCANNED; 2790 bp->b_error = 0; 2791 } 2792 2793 /* 2794 * Flush all dirty buffers associated with a vnode. 2795 */ 2796 loop2: 2797 TAILQ_FOREACH_SAFE(bp, &bo->bo_dirty.bv_hd, b_bobufs, nbp) { 2798 if ((bp->b_vflags & BV_SCANNED) != 0) 2799 continue; 2800 bp->b_vflags |= BV_SCANNED; 2801 if (BUF_LOCK(bp, LK_EXCLUSIVE | LK_NOWAIT, NULL)) { 2802 if (waitfor != MNT_WAIT) 2803 continue; 2804 if (BUF_LOCK(bp, 2805 LK_EXCLUSIVE | LK_INTERLOCK | LK_SLEEPFAIL, 2806 BO_LOCKPTR(bo)) != 0) { 2807 BO_LOCK(bo); 2808 goto loop1; 2809 } 2810 BO_LOCK(bo); 2811 } 2812 BO_UNLOCK(bo); 2813 KASSERT(bp->b_bufobj == bo, 2814 ("bp %p wrong b_bufobj %p should be %p", 2815 bp, bp->b_bufobj, bo)); 2816 if ((bp->b_flags & B_DELWRI) == 0) 2817 panic("fsync: not dirty"); 2818 if ((vp->v_object != NULL) && (bp->b_flags & B_CLUSTEROK)) { 2819 vfs_bio_awrite(bp); 2820 } else { 2821 bremfree(bp); 2822 bawrite(bp); 2823 } 2824 if (maxretry < 1000) 2825 pause("dirty", hz < 1000 ? 1 : hz / 1000); 2826 BO_LOCK(bo); 2827 goto loop2; 2828 } 2829 2830 /* 2831 * If synchronous the caller expects us to completely resolve all 2832 * dirty buffers in the system. Wait for in-progress I/O to 2833 * complete (which could include background bitmap writes), then 2834 * retry if dirty blocks still exist. 2835 */ 2836 if (waitfor == MNT_WAIT) { 2837 bufobj_wwait(bo, 0, 0); 2838 if (bo->bo_dirty.bv_cnt > 0) { 2839 /* 2840 * If we are unable to write any of these buffers 2841 * then we fail now rather than trying endlessly 2842 * to write them out. 2843 */ 2844 TAILQ_FOREACH(bp, &bo->bo_dirty.bv_hd, b_bobufs) 2845 if ((error = bp->b_error) != 0) 2846 break; 2847 if ((mp != NULL && mp->mnt_secondary_writes > 0) || 2848 (error == 0 && --maxretry >= 0)) 2849 goto loop1; 2850 if (error == 0) 2851 error = EAGAIN; 2852 } 2853 } 2854 BO_UNLOCK(bo); 2855 if (error != 0) 2856 vn_printf(vp, "fsync: giving up on dirty (error = %d) ", error); 2857 2858 return (error); 2859 } 2860 2861 /* 2862 * Copies a byte range from invp to outvp. Calls VOP_COPY_FILE_RANGE() 2863 * or vn_generic_copy_file_range() after rangelocking the byte ranges, 2864 * to do the actual copy. 2865 * vn_generic_copy_file_range() is factored out, so it can be called 2866 * from a VOP_COPY_FILE_RANGE() call as well, but handles vnodes from 2867 * different file systems. 2868 */ 2869 int 2870 vn_copy_file_range(struct vnode *invp, off_t *inoffp, struct vnode *outvp, 2871 off_t *outoffp, size_t *lenp, unsigned int flags, struct ucred *incred, 2872 struct ucred *outcred, struct thread *fsize_td) 2873 { 2874 int error; 2875 size_t len; 2876 uint64_t uval; 2877 2878 len = *lenp; 2879 *lenp = 0; /* For error returns. */ 2880 error = 0; 2881 2882 /* Do some sanity checks on the arguments. */ 2883 if (invp->v_type == VDIR || outvp->v_type == VDIR) 2884 error = EISDIR; 2885 else if (*inoffp < 0 || *outoffp < 0 || 2886 invp->v_type != VREG || outvp->v_type != VREG) 2887 error = EINVAL; 2888 if (error != 0) 2889 goto out; 2890 2891 /* Ensure offset + len does not wrap around. */ 2892 uval = *inoffp; 2893 uval += len; 2894 if (uval > INT64_MAX) 2895 len = INT64_MAX - *inoffp; 2896 uval = *outoffp; 2897 uval += len; 2898 if (uval > INT64_MAX) 2899 len = INT64_MAX - *outoffp; 2900 if (len == 0) 2901 goto out; 2902 2903 /* 2904 * If the two vnode are for the same file system, call 2905 * VOP_COPY_FILE_RANGE(), otherwise call vn_generic_copy_file_range() 2906 * which can handle copies across multiple file systems. 2907 */ 2908 *lenp = len; 2909 if (invp->v_mount == outvp->v_mount) 2910 error = VOP_COPY_FILE_RANGE(invp, inoffp, outvp, outoffp, 2911 lenp, flags, incred, outcred, fsize_td); 2912 else 2913 error = vn_generic_copy_file_range(invp, inoffp, outvp, 2914 outoffp, lenp, flags, incred, outcred, fsize_td); 2915 out: 2916 return (error); 2917 } 2918 2919 /* 2920 * Test len bytes of data starting at dat for all bytes == 0. 2921 * Return true if all bytes are zero, false otherwise. 2922 * Expects dat to be well aligned. 2923 */ 2924 static bool 2925 mem_iszero(void *dat, int len) 2926 { 2927 int i; 2928 const u_int *p; 2929 const char *cp; 2930 2931 for (p = dat; len > 0; len -= sizeof(*p), p++) { 2932 if (len >= sizeof(*p)) { 2933 if (*p != 0) 2934 return (false); 2935 } else { 2936 cp = (const char *)p; 2937 for (i = 0; i < len; i++, cp++) 2938 if (*cp != '\0') 2939 return (false); 2940 } 2941 } 2942 return (true); 2943 } 2944 2945 /* 2946 * Look for a hole in the output file and, if found, adjust *outoffp 2947 * and *xferp to skip past the hole. 2948 * *xferp is the entire hole length to be written and xfer2 is how many bytes 2949 * to be written as 0's upon return. 2950 */ 2951 static off_t 2952 vn_skip_hole(struct vnode *outvp, off_t xfer2, off_t *outoffp, off_t *xferp, 2953 off_t *dataoffp, off_t *holeoffp, struct ucred *cred) 2954 { 2955 int error; 2956 off_t delta; 2957 2958 if (*holeoffp == 0 || *holeoffp <= *outoffp) { 2959 *dataoffp = *outoffp; 2960 error = VOP_IOCTL(outvp, FIOSEEKDATA, dataoffp, 0, cred, 2961 curthread); 2962 if (error == 0) { 2963 *holeoffp = *dataoffp; 2964 error = VOP_IOCTL(outvp, FIOSEEKHOLE, holeoffp, 0, cred, 2965 curthread); 2966 } 2967 if (error != 0 || *holeoffp == *dataoffp) { 2968 /* 2969 * Since outvp is unlocked, it may be possible for 2970 * another thread to do a truncate(), lseek(), write() 2971 * creating a hole at startoff between the above 2972 * VOP_IOCTL() calls, if the other thread does not do 2973 * rangelocking. 2974 * If that happens, *holeoffp == *dataoffp and finding 2975 * the hole has failed, so disable vn_skip_hole(). 2976 */ 2977 *holeoffp = -1; /* Disable use of vn_skip_hole(). */ 2978 return (xfer2); 2979 } 2980 KASSERT(*dataoffp >= *outoffp, 2981 ("vn_skip_hole: dataoff=%jd < outoff=%jd", 2982 (intmax_t)*dataoffp, (intmax_t)*outoffp)); 2983 KASSERT(*holeoffp > *dataoffp, 2984 ("vn_skip_hole: holeoff=%jd <= dataoff=%jd", 2985 (intmax_t)*holeoffp, (intmax_t)*dataoffp)); 2986 } 2987 2988 /* 2989 * If there is a hole before the data starts, advance *outoffp and 2990 * *xferp past the hole. 2991 */ 2992 if (*dataoffp > *outoffp) { 2993 delta = *dataoffp - *outoffp; 2994 if (delta >= *xferp) { 2995 /* Entire *xferp is a hole. */ 2996 *outoffp += *xferp; 2997 *xferp = 0; 2998 return (0); 2999 } 3000 *xferp -= delta; 3001 *outoffp += delta; 3002 xfer2 = MIN(xfer2, *xferp); 3003 } 3004 3005 /* 3006 * If a hole starts before the end of this xfer2, reduce this xfer2 so 3007 * that the write ends at the start of the hole. 3008 * *holeoffp should always be greater than *outoffp, but for the 3009 * non-INVARIANTS case, check this to make sure xfer2 remains a sane 3010 * value. 3011 */ 3012 if (*holeoffp > *outoffp && *holeoffp < *outoffp + xfer2) 3013 xfer2 = *holeoffp - *outoffp; 3014 return (xfer2); 3015 } 3016 3017 /* 3018 * Write an xfer sized chunk to outvp in blksize blocks from dat. 3019 * dat is a maximum of blksize in length and can be written repeatedly in 3020 * the chunk. 3021 * If growfile == true, just grow the file via vn_truncate_locked() instead 3022 * of doing actual writes. 3023 * If checkhole == true, a hole is being punched, so skip over any hole 3024 * already in the output file. 3025 */ 3026 static int 3027 vn_write_outvp(struct vnode *outvp, char *dat, off_t outoff, off_t xfer, 3028 u_long blksize, bool growfile, bool checkhole, struct ucred *cred) 3029 { 3030 struct mount *mp; 3031 off_t dataoff, holeoff, xfer2; 3032 int error, lckf; 3033 3034 /* 3035 * Loop around doing writes of blksize until write has been completed. 3036 * Lock/unlock on each loop iteration so that a bwillwrite() can be 3037 * done for each iteration, since the xfer argument can be very 3038 * large if there is a large hole to punch in the output file. 3039 */ 3040 error = 0; 3041 holeoff = 0; 3042 do { 3043 xfer2 = MIN(xfer, blksize); 3044 if (checkhole) { 3045 /* 3046 * Punching a hole. Skip writing if there is 3047 * already a hole in the output file. 3048 */ 3049 xfer2 = vn_skip_hole(outvp, xfer2, &outoff, &xfer, 3050 &dataoff, &holeoff, cred); 3051 if (xfer == 0) 3052 break; 3053 if (holeoff < 0) 3054 checkhole = false; 3055 KASSERT(xfer2 > 0, ("vn_write_outvp: xfer2=%jd", 3056 (intmax_t)xfer2)); 3057 } 3058 bwillwrite(); 3059 mp = NULL; 3060 error = vn_start_write(outvp, &mp, V_WAIT); 3061 if (error != 0) 3062 break; 3063 if (growfile) { 3064 error = vn_lock(outvp, LK_EXCLUSIVE); 3065 if (error == 0) { 3066 error = vn_truncate_locked(outvp, outoff + xfer, 3067 false, cred); 3068 VOP_UNLOCK(outvp); 3069 } 3070 } else { 3071 if (MNT_SHARED_WRITES(mp)) 3072 lckf = LK_SHARED; 3073 else 3074 lckf = LK_EXCLUSIVE; 3075 error = vn_lock(outvp, lckf); 3076 if (error == 0) { 3077 error = vn_rdwr(UIO_WRITE, outvp, dat, xfer2, 3078 outoff, UIO_SYSSPACE, IO_NODELOCKED, 3079 curthread->td_ucred, cred, NULL, curthread); 3080 outoff += xfer2; 3081 xfer -= xfer2; 3082 VOP_UNLOCK(outvp); 3083 } 3084 } 3085 if (mp != NULL) 3086 vn_finished_write(mp); 3087 } while (!growfile && xfer > 0 && error == 0); 3088 return (error); 3089 } 3090 3091 /* 3092 * Copy a byte range of one file to another. This function can handle the 3093 * case where invp and outvp are on different file systems. 3094 * It can also be called by a VOP_COPY_FILE_RANGE() to do the work, if there 3095 * is no better file system specific way to do it. 3096 */ 3097 int 3098 vn_generic_copy_file_range(struct vnode *invp, off_t *inoffp, 3099 struct vnode *outvp, off_t *outoffp, size_t *lenp, unsigned int flags, 3100 struct ucred *incred, struct ucred *outcred, struct thread *fsize_td) 3101 { 3102 struct vattr va, inva; 3103 struct mount *mp; 3104 struct uio io; 3105 off_t startoff, endoff, xfer, xfer2; 3106 u_long blksize; 3107 int error, interrupted; 3108 bool cantseek, readzeros, eof, lastblock, holetoeof; 3109 ssize_t aresid; 3110 size_t copylen, len, rem, savlen; 3111 char *dat; 3112 long holein, holeout; 3113 3114 holein = holeout = 0; 3115 savlen = len = *lenp; 3116 error = 0; 3117 interrupted = 0; 3118 dat = NULL; 3119 3120 error = vn_lock(invp, LK_SHARED); 3121 if (error != 0) 3122 goto out; 3123 if (VOP_PATHCONF(invp, _PC_MIN_HOLE_SIZE, &holein) != 0) 3124 holein = 0; 3125 if (holein > 0) 3126 error = VOP_GETATTR(invp, &inva, incred); 3127 VOP_UNLOCK(invp); 3128 if (error != 0) 3129 goto out; 3130 3131 mp = NULL; 3132 error = vn_start_write(outvp, &mp, V_WAIT); 3133 if (error == 0) 3134 error = vn_lock(outvp, LK_EXCLUSIVE); 3135 if (error == 0) { 3136 /* 3137 * If fsize_td != NULL, do a vn_rlimit_fsize() call, 3138 * now that outvp is locked. 3139 */ 3140 if (fsize_td != NULL) { 3141 io.uio_offset = *outoffp; 3142 io.uio_resid = len; 3143 error = vn_rlimit_fsize(outvp, &io, fsize_td); 3144 if (error != 0) 3145 error = EFBIG; 3146 } 3147 if (VOP_PATHCONF(outvp, _PC_MIN_HOLE_SIZE, &holeout) != 0) 3148 holeout = 0; 3149 /* 3150 * Holes that are past EOF do not need to be written as a block 3151 * of zero bytes. So, truncate the output file as far as 3152 * possible and then use va.va_size to decide if writing 0 3153 * bytes is necessary in the loop below. 3154 */ 3155 if (error == 0) 3156 error = VOP_GETATTR(outvp, &va, outcred); 3157 if (error == 0 && va.va_size > *outoffp && va.va_size <= 3158 *outoffp + len) { 3159 #ifdef MAC 3160 error = mac_vnode_check_write(curthread->td_ucred, 3161 outcred, outvp); 3162 if (error == 0) 3163 #endif 3164 error = vn_truncate_locked(outvp, *outoffp, 3165 false, outcred); 3166 if (error == 0) 3167 va.va_size = *outoffp; 3168 } 3169 VOP_UNLOCK(outvp); 3170 } 3171 if (mp != NULL) 3172 vn_finished_write(mp); 3173 if (error != 0) 3174 goto out; 3175 3176 /* 3177 * Set the blksize to the larger of the hole sizes for invp and outvp. 3178 * If hole sizes aren't available, set the blksize to the larger 3179 * f_iosize of invp and outvp. 3180 * This code expects the hole sizes and f_iosizes to be powers of 2. 3181 * This value is clipped at 4Kbytes and 1Mbyte. 3182 */ 3183 blksize = MAX(holein, holeout); 3184 3185 /* Clip len to end at an exact multiple of hole size. */ 3186 if (blksize > 1) { 3187 rem = *inoffp % blksize; 3188 if (rem > 0) 3189 rem = blksize - rem; 3190 if (len > rem && len - rem > blksize) 3191 len = savlen = rounddown(len - rem, blksize) + rem; 3192 } 3193 3194 if (blksize <= 1) 3195 blksize = MAX(invp->v_mount->mnt_stat.f_iosize, 3196 outvp->v_mount->mnt_stat.f_iosize); 3197 if (blksize < 4096) 3198 blksize = 4096; 3199 else if (blksize > 1024 * 1024) 3200 blksize = 1024 * 1024; 3201 dat = malloc(blksize, M_TEMP, M_WAITOK); 3202 3203 /* 3204 * If VOP_IOCTL(FIOSEEKHOLE) works for invp, use it and FIOSEEKDATA 3205 * to find holes. Otherwise, just scan the read block for all 0s 3206 * in the inner loop where the data copying is done. 3207 * Note that some file systems such as NFSv3, NFSv4.0 and NFSv4.1 may 3208 * support holes on the server, but do not support FIOSEEKHOLE. 3209 */ 3210 holetoeof = eof = false; 3211 while (len > 0 && error == 0 && !eof && interrupted == 0) { 3212 endoff = 0; /* To shut up compilers. */ 3213 cantseek = true; 3214 startoff = *inoffp; 3215 copylen = len; 3216 3217 /* 3218 * Find the next data area. If there is just a hole to EOF, 3219 * FIOSEEKDATA should fail with ENXIO. 3220 * (I do not know if any file system will report a hole to 3221 * EOF via FIOSEEKHOLE, but I am pretty sure FIOSEEKDATA 3222 * will fail for those file systems.) 3223 * 3224 * For input files that don't support FIOSEEKDATA/FIOSEEKHOLE, 3225 * the code just falls through to the inner copy loop. 3226 */ 3227 error = EINVAL; 3228 if (holein > 0) { 3229 error = VOP_IOCTL(invp, FIOSEEKDATA, &startoff, 0, 3230 incred, curthread); 3231 if (error == ENXIO) { 3232 startoff = endoff = inva.va_size; 3233 eof = holetoeof = true; 3234 error = 0; 3235 } 3236 } 3237 if (error == 0 && !holetoeof) { 3238 endoff = startoff; 3239 error = VOP_IOCTL(invp, FIOSEEKHOLE, &endoff, 0, 3240 incred, curthread); 3241 /* 3242 * Since invp is unlocked, it may be possible for 3243 * another thread to do a truncate(), lseek(), write() 3244 * creating a hole at startoff between the above 3245 * VOP_IOCTL() calls, if the other thread does not do 3246 * rangelocking. 3247 * If that happens, startoff == endoff and finding 3248 * the hole has failed, so set an error. 3249 */ 3250 if (error == 0 && startoff == endoff) 3251 error = EINVAL; /* Any error. Reset to 0. */ 3252 } 3253 if (error == 0) { 3254 if (startoff > *inoffp) { 3255 /* Found hole before data block. */ 3256 xfer = MIN(startoff - *inoffp, len); 3257 if (*outoffp < va.va_size) { 3258 /* Must write 0s to punch hole. */ 3259 xfer2 = MIN(va.va_size - *outoffp, 3260 xfer); 3261 memset(dat, 0, MIN(xfer2, blksize)); 3262 error = vn_write_outvp(outvp, dat, 3263 *outoffp, xfer2, blksize, false, 3264 holeout > 0, outcred); 3265 } 3266 3267 if (error == 0 && *outoffp + xfer > 3268 va.va_size && (xfer == len || holetoeof)) { 3269 /* Grow output file (hole at end). */ 3270 error = vn_write_outvp(outvp, dat, 3271 *outoffp, xfer, blksize, true, 3272 false, outcred); 3273 } 3274 if (error == 0) { 3275 *inoffp += xfer; 3276 *outoffp += xfer; 3277 len -= xfer; 3278 if (len < savlen) 3279 interrupted = sig_intr(); 3280 } 3281 } 3282 copylen = MIN(len, endoff - startoff); 3283 cantseek = false; 3284 } else { 3285 cantseek = true; 3286 startoff = *inoffp; 3287 copylen = len; 3288 error = 0; 3289 } 3290 3291 xfer = blksize; 3292 if (cantseek) { 3293 /* 3294 * Set first xfer to end at a block boundary, so that 3295 * holes are more likely detected in the loop below via 3296 * the for all bytes 0 method. 3297 */ 3298 xfer -= (*inoffp % blksize); 3299 } 3300 /* Loop copying the data block. */ 3301 while (copylen > 0 && error == 0 && !eof && interrupted == 0) { 3302 if (copylen < xfer) 3303 xfer = copylen; 3304 error = vn_lock(invp, LK_SHARED); 3305 if (error != 0) 3306 goto out; 3307 error = vn_rdwr(UIO_READ, invp, dat, xfer, 3308 startoff, UIO_SYSSPACE, IO_NODELOCKED, 3309 curthread->td_ucred, incred, &aresid, 3310 curthread); 3311 VOP_UNLOCK(invp); 3312 lastblock = false; 3313 if (error == 0 && aresid > 0) { 3314 /* Stop the copy at EOF on the input file. */ 3315 xfer -= aresid; 3316 eof = true; 3317 lastblock = true; 3318 } 3319 if (error == 0) { 3320 /* 3321 * Skip the write for holes past the initial EOF 3322 * of the output file, unless this is the last 3323 * write of the output file at EOF. 3324 */ 3325 readzeros = cantseek ? mem_iszero(dat, xfer) : 3326 false; 3327 if (xfer == len) 3328 lastblock = true; 3329 if (!cantseek || *outoffp < va.va_size || 3330 lastblock || !readzeros) 3331 error = vn_write_outvp(outvp, dat, 3332 *outoffp, xfer, blksize, 3333 readzeros && lastblock && 3334 *outoffp >= va.va_size, false, 3335 outcred); 3336 if (error == 0) { 3337 *inoffp += xfer; 3338 startoff += xfer; 3339 *outoffp += xfer; 3340 copylen -= xfer; 3341 len -= xfer; 3342 if (len < savlen) 3343 interrupted = sig_intr(); 3344 } 3345 } 3346 xfer = blksize; 3347 } 3348 } 3349 out: 3350 *lenp = savlen - len; 3351 free(dat, M_TEMP); 3352 return (error); 3353 } 3354 3355 static int 3356 vn_fallocate(struct file *fp, off_t offset, off_t len, struct thread *td) 3357 { 3358 struct mount *mp; 3359 struct vnode *vp; 3360 off_t olen, ooffset; 3361 int error; 3362 #ifdef AUDIT 3363 int audited_vnode1 = 0; 3364 #endif 3365 3366 vp = fp->f_vnode; 3367 if (vp->v_type != VREG) 3368 return (ENODEV); 3369 3370 /* Allocating blocks may take a long time, so iterate. */ 3371 for (;;) { 3372 olen = len; 3373 ooffset = offset; 3374 3375 bwillwrite(); 3376 mp = NULL; 3377 error = vn_start_write(vp, &mp, V_WAIT | PCATCH); 3378 if (error != 0) 3379 break; 3380 error = vn_lock(vp, LK_EXCLUSIVE); 3381 if (error != 0) { 3382 vn_finished_write(mp); 3383 break; 3384 } 3385 #ifdef AUDIT 3386 if (!audited_vnode1) { 3387 AUDIT_ARG_VNODE1(vp); 3388 audited_vnode1 = 1; 3389 } 3390 #endif 3391 #ifdef MAC 3392 error = mac_vnode_check_write(td->td_ucred, fp->f_cred, vp); 3393 if (error == 0) 3394 #endif 3395 error = VOP_ALLOCATE(vp, &offset, &len); 3396 VOP_UNLOCK(vp); 3397 vn_finished_write(mp); 3398 3399 if (olen + ooffset != offset + len) { 3400 panic("offset + len changed from %jx/%jx to %jx/%jx", 3401 ooffset, olen, offset, len); 3402 } 3403 if (error != 0 || len == 0) 3404 break; 3405 KASSERT(olen > len, ("Iteration did not make progress?")); 3406 maybe_yield(); 3407 } 3408 3409 return (error); 3410 } 3411 3412 static u_long vn_lock_pair_pause_cnt; 3413 SYSCTL_ULONG(_debug, OID_AUTO, vn_lock_pair_pause, CTLFLAG_RD, 3414 &vn_lock_pair_pause_cnt, 0, 3415 "Count of vn_lock_pair deadlocks"); 3416 3417 u_int vn_lock_pair_pause_max; 3418 SYSCTL_UINT(_debug, OID_AUTO, vn_lock_pair_pause_max, CTLFLAG_RW, 3419 &vn_lock_pair_pause_max, 0, 3420 "Max ticks for vn_lock_pair deadlock avoidance sleep"); 3421 3422 static void 3423 vn_lock_pair_pause(const char *wmesg) 3424 { 3425 atomic_add_long(&vn_lock_pair_pause_cnt, 1); 3426 pause(wmesg, prng32_bounded(vn_lock_pair_pause_max)); 3427 } 3428 3429 /* 3430 * Lock pair of vnodes vp1, vp2, avoiding lock order reversal. 3431 * vp1_locked indicates whether vp1 is exclusively locked; if not, vp1 3432 * must be unlocked. Same for vp2 and vp2_locked. One of the vnodes 3433 * can be NULL. 3434 * 3435 * The function returns with both vnodes exclusively locked, and 3436 * guarantees that it does not create lock order reversal with other 3437 * threads during its execution. Both vnodes could be unlocked 3438 * temporary (and reclaimed). 3439 */ 3440 void 3441 vn_lock_pair(struct vnode *vp1, bool vp1_locked, struct vnode *vp2, 3442 bool vp2_locked) 3443 { 3444 int error; 3445 3446 if (vp1 == NULL && vp2 == NULL) 3447 return; 3448 if (vp1 != NULL) { 3449 if (vp1_locked) 3450 ASSERT_VOP_ELOCKED(vp1, "vp1"); 3451 else 3452 ASSERT_VOP_UNLOCKED(vp1, "vp1"); 3453 } else { 3454 vp1_locked = true; 3455 } 3456 if (vp2 != NULL) { 3457 if (vp2_locked) 3458 ASSERT_VOP_ELOCKED(vp2, "vp2"); 3459 else 3460 ASSERT_VOP_UNLOCKED(vp2, "vp2"); 3461 } else { 3462 vp2_locked = true; 3463 } 3464 if (!vp1_locked && !vp2_locked) { 3465 vn_lock(vp1, LK_EXCLUSIVE | LK_RETRY); 3466 vp1_locked = true; 3467 } 3468 3469 for (;;) { 3470 if (vp1_locked && vp2_locked) 3471 break; 3472 if (vp1_locked && vp2 != NULL) { 3473 if (vp1 != NULL) { 3474 error = VOP_LOCK1(vp2, LK_EXCLUSIVE | LK_NOWAIT, 3475 __FILE__, __LINE__); 3476 if (error == 0) 3477 break; 3478 VOP_UNLOCK(vp1); 3479 vp1_locked = false; 3480 vn_lock_pair_pause("vlp1"); 3481 } 3482 vn_lock(vp2, LK_EXCLUSIVE | LK_RETRY); 3483 vp2_locked = true; 3484 } 3485 if (vp2_locked && vp1 != NULL) { 3486 if (vp2 != NULL) { 3487 error = VOP_LOCK1(vp1, LK_EXCLUSIVE | LK_NOWAIT, 3488 __FILE__, __LINE__); 3489 if (error == 0) 3490 break; 3491 VOP_UNLOCK(vp2); 3492 vp2_locked = false; 3493 vn_lock_pair_pause("vlp2"); 3494 } 3495 vn_lock(vp1, LK_EXCLUSIVE | LK_RETRY); 3496 vp1_locked = true; 3497 } 3498 } 3499 if (vp1 != NULL) 3500 ASSERT_VOP_ELOCKED(vp1, "vp1 ret"); 3501 if (vp2 != NULL) 3502 ASSERT_VOP_ELOCKED(vp2, "vp2 ret"); 3503 } 3504