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 #include <sys/ktrace.h> 83 84 #include <security/audit/audit.h> 85 #include <security/mac/mac_framework.h> 86 87 #include <vm/vm.h> 88 #include <vm/vm_extern.h> 89 #include <vm/pmap.h> 90 #include <vm/vm_map.h> 91 #include <vm/vm_object.h> 92 #include <vm/vm_page.h> 93 #include <vm/vm_pager.h> 94 95 #ifdef HWPMC_HOOKS 96 #include <sys/pmckern.h> 97 #endif 98 99 static fo_rdwr_t vn_read; 100 static fo_rdwr_t vn_write; 101 static fo_rdwr_t vn_io_fault; 102 static fo_truncate_t vn_truncate; 103 static fo_ioctl_t vn_ioctl; 104 static fo_poll_t vn_poll; 105 static fo_kqfilter_t vn_kqfilter; 106 static fo_close_t vn_closefile; 107 static fo_mmap_t vn_mmap; 108 static fo_fallocate_t vn_fallocate; 109 static fo_fspacectl_t vn_fspacectl; 110 111 struct fileops vnops = { 112 .fo_read = vn_io_fault, 113 .fo_write = vn_io_fault, 114 .fo_truncate = vn_truncate, 115 .fo_ioctl = vn_ioctl, 116 .fo_poll = vn_poll, 117 .fo_kqfilter = vn_kqfilter, 118 .fo_stat = vn_statfile, 119 .fo_close = vn_closefile, 120 .fo_chmod = vn_chmod, 121 .fo_chown = vn_chown, 122 .fo_sendfile = vn_sendfile, 123 .fo_seek = vn_seek, 124 .fo_fill_kinfo = vn_fill_kinfo, 125 .fo_mmap = vn_mmap, 126 .fo_fallocate = vn_fallocate, 127 .fo_fspacectl = vn_fspacectl, 128 .fo_flags = DFLAG_PASSABLE | DFLAG_SEEKABLE 129 }; 130 131 const u_int io_hold_cnt = 16; 132 static int vn_io_fault_enable = 1; 133 SYSCTL_INT(_debug, OID_AUTO, vn_io_fault_enable, CTLFLAG_RWTUN, 134 &vn_io_fault_enable, 0, "Enable vn_io_fault lock avoidance"); 135 static int vn_io_fault_prefault = 0; 136 SYSCTL_INT(_debug, OID_AUTO, vn_io_fault_prefault, CTLFLAG_RWTUN, 137 &vn_io_fault_prefault, 0, "Enable vn_io_fault prefaulting"); 138 static int vn_io_pgcache_read_enable = 1; 139 SYSCTL_INT(_debug, OID_AUTO, vn_io_pgcache_read_enable, CTLFLAG_RWTUN, 140 &vn_io_pgcache_read_enable, 0, 141 "Enable copying from page cache for reads, avoiding fs"); 142 static u_long vn_io_faults_cnt; 143 SYSCTL_ULONG(_debug, OID_AUTO, vn_io_faults, CTLFLAG_RD, 144 &vn_io_faults_cnt, 0, "Count of vn_io_fault lock avoidance triggers"); 145 146 static int vfs_allow_read_dir = 0; 147 SYSCTL_INT(_security_bsd, OID_AUTO, allow_read_dir, CTLFLAG_RW, 148 &vfs_allow_read_dir, 0, 149 "Enable read(2) of directory by root for filesystems that support it"); 150 151 /* 152 * Returns true if vn_io_fault mode of handling the i/o request should 153 * be used. 154 */ 155 static bool 156 do_vn_io_fault(struct vnode *vp, struct uio *uio) 157 { 158 struct mount *mp; 159 160 return (uio->uio_segflg == UIO_USERSPACE && vp->v_type == VREG && 161 (mp = vp->v_mount) != NULL && 162 (mp->mnt_kern_flag & MNTK_NO_IOPF) != 0 && vn_io_fault_enable); 163 } 164 165 /* 166 * Structure used to pass arguments to vn_io_fault1(), to do either 167 * file- or vnode-based I/O calls. 168 */ 169 struct vn_io_fault_args { 170 enum { 171 VN_IO_FAULT_FOP, 172 VN_IO_FAULT_VOP 173 } kind; 174 struct ucred *cred; 175 int flags; 176 union { 177 struct fop_args_tag { 178 struct file *fp; 179 fo_rdwr_t *doio; 180 } fop_args; 181 struct vop_args_tag { 182 struct vnode *vp; 183 } vop_args; 184 } args; 185 }; 186 187 static int vn_io_fault1(struct vnode *vp, struct uio *uio, 188 struct vn_io_fault_args *args, struct thread *td); 189 190 int 191 vn_open(struct nameidata *ndp, int *flagp, int cmode, struct file *fp) 192 { 193 struct thread *td = ndp->ni_cnd.cn_thread; 194 195 return (vn_open_cred(ndp, flagp, cmode, 0, td->td_ucred, fp)); 196 } 197 198 static uint64_t 199 open2nameif(int fmode, u_int vn_open_flags) 200 { 201 uint64_t res; 202 203 res = ISOPEN | LOCKLEAF; 204 if ((fmode & O_RESOLVE_BENEATH) != 0) 205 res |= RBENEATH; 206 if ((fmode & O_EMPTY_PATH) != 0) 207 res |= EMPTYPATH; 208 if ((fmode & FREAD) != 0) 209 res |= OPENREAD; 210 if ((fmode & FWRITE) != 0) 211 res |= OPENWRITE; 212 if ((vn_open_flags & VN_OPEN_NOAUDIT) == 0) 213 res |= AUDITVNODE1; 214 if ((vn_open_flags & VN_OPEN_NOCAPCHECK) != 0) 215 res |= NOCAPCHECK; 216 return (res); 217 } 218 219 /* 220 * Common code for vnode open operations via a name lookup. 221 * Lookup the vnode and invoke VOP_CREATE if needed. 222 * Check permissions, and call the VOP_OPEN or VOP_CREATE routine. 223 * 224 * Note that this does NOT free nameidata for the successful case, 225 * due to the NDINIT being done elsewhere. 226 */ 227 int 228 vn_open_cred(struct nameidata *ndp, int *flagp, int cmode, u_int vn_open_flags, 229 struct ucred *cred, struct file *fp) 230 { 231 struct vnode *vp; 232 struct mount *mp; 233 struct thread *td = ndp->ni_cnd.cn_thread; 234 struct vattr vat; 235 struct vattr *vap = &vat; 236 int fmode, error; 237 bool first_open; 238 239 restart: 240 first_open = false; 241 fmode = *flagp; 242 if ((fmode & (O_CREAT | O_EXCL | O_DIRECTORY)) == (O_CREAT | 243 O_EXCL | O_DIRECTORY) || 244 (fmode & (O_CREAT | O_EMPTY_PATH)) == (O_CREAT | O_EMPTY_PATH)) 245 return (EINVAL); 246 else if ((fmode & (O_CREAT | O_DIRECTORY)) == O_CREAT) { 247 ndp->ni_cnd.cn_nameiop = CREATE; 248 ndp->ni_cnd.cn_flags = open2nameif(fmode, vn_open_flags); 249 /* 250 * Set NOCACHE to avoid flushing the cache when 251 * rolling in many files at once. 252 * 253 * Set NC_KEEPPOSENTRY to keep positive entries if they already 254 * exist despite NOCACHE. 255 */ 256 ndp->ni_cnd.cn_flags |= LOCKPARENT | NOCACHE | NC_KEEPPOSENTRY; 257 if ((fmode & O_EXCL) == 0 && (fmode & O_NOFOLLOW) == 0) 258 ndp->ni_cnd.cn_flags |= FOLLOW; 259 if ((vn_open_flags & VN_OPEN_INVFS) == 0) 260 bwillwrite(); 261 if ((error = namei(ndp)) != 0) 262 return (error); 263 if (ndp->ni_vp == NULL) { 264 VATTR_NULL(vap); 265 vap->va_type = VREG; 266 vap->va_mode = cmode; 267 if (fmode & O_EXCL) 268 vap->va_vaflags |= VA_EXCLUSIVE; 269 if (vn_start_write(ndp->ni_dvp, &mp, V_NOWAIT) != 0) { 270 NDFREE(ndp, NDF_ONLY_PNBUF); 271 vput(ndp->ni_dvp); 272 if ((error = vn_start_write(NULL, &mp, 273 V_XSLEEP | PCATCH)) != 0) 274 return (error); 275 NDREINIT(ndp); 276 goto restart; 277 } 278 if ((vn_open_flags & VN_OPEN_NAMECACHE) != 0) 279 ndp->ni_cnd.cn_flags |= MAKEENTRY; 280 #ifdef MAC 281 error = mac_vnode_check_create(cred, ndp->ni_dvp, 282 &ndp->ni_cnd, vap); 283 if (error == 0) 284 #endif 285 error = VOP_CREATE(ndp->ni_dvp, &ndp->ni_vp, 286 &ndp->ni_cnd, vap); 287 vp = ndp->ni_vp; 288 if (error == 0 && (fmode & O_EXCL) != 0 && 289 (fmode & (O_EXLOCK | O_SHLOCK)) != 0) { 290 VI_LOCK(vp); 291 vp->v_iflag |= VI_FOPENING; 292 VI_UNLOCK(vp); 293 first_open = true; 294 } 295 VOP_VPUT_PAIR(ndp->ni_dvp, error == 0 ? &vp : NULL, 296 false); 297 vn_finished_write(mp); 298 if (error) { 299 NDFREE(ndp, NDF_ONLY_PNBUF); 300 if (error == ERELOOKUP) { 301 NDREINIT(ndp); 302 goto restart; 303 } 304 return (error); 305 } 306 fmode &= ~O_TRUNC; 307 } else { 308 if (ndp->ni_dvp == ndp->ni_vp) 309 vrele(ndp->ni_dvp); 310 else 311 vput(ndp->ni_dvp); 312 ndp->ni_dvp = NULL; 313 vp = ndp->ni_vp; 314 if (fmode & O_EXCL) { 315 error = EEXIST; 316 goto bad; 317 } 318 if (vp->v_type == VDIR) { 319 error = EISDIR; 320 goto bad; 321 } 322 fmode &= ~O_CREAT; 323 } 324 } else { 325 ndp->ni_cnd.cn_nameiop = LOOKUP; 326 ndp->ni_cnd.cn_flags = open2nameif(fmode, vn_open_flags); 327 ndp->ni_cnd.cn_flags |= (fmode & O_NOFOLLOW) != 0 ? NOFOLLOW : 328 FOLLOW; 329 if ((fmode & FWRITE) == 0) 330 ndp->ni_cnd.cn_flags |= LOCKSHARED; 331 if ((error = namei(ndp)) != 0) 332 return (error); 333 vp = ndp->ni_vp; 334 } 335 error = vn_open_vnode(vp, fmode, cred, td, fp); 336 if (first_open) { 337 VI_LOCK(vp); 338 vp->v_iflag &= ~VI_FOPENING; 339 wakeup(vp); 340 VI_UNLOCK(vp); 341 } 342 if (error) 343 goto bad; 344 *flagp = fmode; 345 return (0); 346 bad: 347 NDFREE(ndp, NDF_ONLY_PNBUF); 348 vput(vp); 349 *flagp = fmode; 350 ndp->ni_vp = NULL; 351 return (error); 352 } 353 354 static int 355 vn_open_vnode_advlock(struct vnode *vp, int fmode, struct file *fp) 356 { 357 struct flock lf; 358 int error, lock_flags, type; 359 360 ASSERT_VOP_LOCKED(vp, "vn_open_vnode_advlock"); 361 if ((fmode & (O_EXLOCK | O_SHLOCK)) == 0) 362 return (0); 363 KASSERT(fp != NULL, ("open with flock requires fp")); 364 if (fp->f_type != DTYPE_NONE && fp->f_type != DTYPE_VNODE) 365 return (EOPNOTSUPP); 366 367 lock_flags = VOP_ISLOCKED(vp); 368 VOP_UNLOCK(vp); 369 370 lf.l_whence = SEEK_SET; 371 lf.l_start = 0; 372 lf.l_len = 0; 373 lf.l_type = (fmode & O_EXLOCK) != 0 ? F_WRLCK : F_RDLCK; 374 type = F_FLOCK; 375 if ((fmode & FNONBLOCK) == 0) 376 type |= F_WAIT; 377 if ((fmode & (O_CREAT | O_EXCL)) == (O_CREAT | O_EXCL)) 378 type |= F_FIRSTOPEN; 379 error = VOP_ADVLOCK(vp, (caddr_t)fp, F_SETLK, &lf, type); 380 if (error == 0) 381 fp->f_flag |= FHASLOCK; 382 383 vn_lock(vp, lock_flags | LK_RETRY); 384 return (error); 385 } 386 387 /* 388 * Common code for vnode open operations once a vnode is located. 389 * Check permissions, and call the VOP_OPEN routine. 390 */ 391 int 392 vn_open_vnode(struct vnode *vp, int fmode, struct ucred *cred, 393 struct thread *td, struct file *fp) 394 { 395 accmode_t accmode; 396 int error; 397 398 if (vp->v_type == VLNK) { 399 if ((fmode & O_PATH) == 0 || (fmode & FEXEC) != 0) 400 return (EMLINK); 401 } 402 if (vp->v_type == VSOCK) 403 return (EOPNOTSUPP); 404 if (vp->v_type != VDIR && fmode & O_DIRECTORY) 405 return (ENOTDIR); 406 407 accmode = 0; 408 if ((fmode & O_PATH) == 0) { 409 if ((fmode & (FWRITE | O_TRUNC)) != 0) { 410 if (vp->v_type == VDIR) 411 return (EISDIR); 412 accmode |= VWRITE; 413 } 414 if ((fmode & FREAD) != 0) 415 accmode |= VREAD; 416 if ((fmode & O_APPEND) && (fmode & FWRITE)) 417 accmode |= VAPPEND; 418 #ifdef MAC 419 if ((fmode & O_CREAT) != 0) 420 accmode |= VCREAT; 421 #endif 422 } 423 if ((fmode & FEXEC) != 0) 424 accmode |= VEXEC; 425 #ifdef MAC 426 if ((fmode & O_VERIFY) != 0) 427 accmode |= VVERIFY; 428 error = mac_vnode_check_open(cred, vp, accmode); 429 if (error != 0) 430 return (error); 431 432 accmode &= ~(VCREAT | VVERIFY); 433 #endif 434 if ((fmode & O_CREAT) == 0 && accmode != 0) { 435 error = VOP_ACCESS(vp, accmode, cred, td); 436 if (error != 0) 437 return (error); 438 } 439 if ((fmode & O_PATH) != 0) { 440 if (vp->v_type == VFIFO) 441 error = EPIPE; 442 else 443 error = VOP_ACCESS(vp, VREAD, cred, td); 444 if (error == 0) 445 fp->f_flag |= FKQALLOWED; 446 return (0); 447 } 448 449 if (vp->v_type == VFIFO && VOP_ISLOCKED(vp) != LK_EXCLUSIVE) 450 vn_lock(vp, LK_UPGRADE | LK_RETRY); 451 error = VOP_OPEN(vp, fmode, cred, td, fp); 452 if (error != 0) 453 return (error); 454 455 error = vn_open_vnode_advlock(vp, fmode, fp); 456 if (error == 0 && (fmode & FWRITE) != 0) { 457 error = VOP_ADD_WRITECOUNT(vp, 1); 458 if (error == 0) { 459 CTR3(KTR_VFS, "%s: vp %p v_writecount increased to %d", 460 __func__, vp, vp->v_writecount); 461 } 462 } 463 464 /* 465 * Error from advlock or VOP_ADD_WRITECOUNT() still requires 466 * calling VOP_CLOSE() to pair with earlier VOP_OPEN(). 467 */ 468 if (error != 0) { 469 if (fp != NULL) { 470 /* 471 * Arrange the call by having fdrop() to use 472 * vn_closefile(). This is to satisfy 473 * filesystems like devfs or tmpfs, which 474 * override fo_close(). 475 */ 476 fp->f_flag |= FOPENFAILED; 477 fp->f_vnode = vp; 478 if (fp->f_ops == &badfileops) { 479 fp->f_type = DTYPE_VNODE; 480 fp->f_ops = &vnops; 481 } 482 vref(vp); 483 } else { 484 /* 485 * If there is no fp, due to kernel-mode open, 486 * we can call VOP_CLOSE() now. 487 */ 488 if (vp->v_type != VFIFO && (fmode & FWRITE) != 0 && 489 !MNT_EXTENDED_SHARED(vp->v_mount) && 490 VOP_ISLOCKED(vp) != LK_EXCLUSIVE) 491 vn_lock(vp, LK_UPGRADE | LK_RETRY); 492 (void)VOP_CLOSE(vp, fmode & (FREAD | FWRITE | FEXEC), 493 cred, td); 494 } 495 } 496 497 ASSERT_VOP_LOCKED(vp, "vn_open_vnode"); 498 return (error); 499 500 } 501 502 /* 503 * Check for write permissions on the specified vnode. 504 * Prototype text segments cannot be written. 505 * It is racy. 506 */ 507 int 508 vn_writechk(struct vnode *vp) 509 { 510 511 ASSERT_VOP_LOCKED(vp, "vn_writechk"); 512 /* 513 * If there's shared text associated with 514 * the vnode, try to free it up once. If 515 * we fail, we can't allow writing. 516 */ 517 if (VOP_IS_TEXT(vp)) 518 return (ETXTBSY); 519 520 return (0); 521 } 522 523 /* 524 * Vnode close call 525 */ 526 static int 527 vn_close1(struct vnode *vp, int flags, struct ucred *file_cred, 528 struct thread *td, bool keep_ref) 529 { 530 struct mount *mp; 531 int error, lock_flags; 532 533 if (vp->v_type != VFIFO && (flags & FWRITE) == 0 && 534 MNT_EXTENDED_SHARED(vp->v_mount)) 535 lock_flags = LK_SHARED; 536 else 537 lock_flags = LK_EXCLUSIVE; 538 539 vn_start_write(vp, &mp, V_WAIT); 540 vn_lock(vp, lock_flags | LK_RETRY); 541 AUDIT_ARG_VNODE1(vp); 542 if ((flags & (FWRITE | FOPENFAILED)) == FWRITE) { 543 VOP_ADD_WRITECOUNT_CHECKED(vp, -1); 544 CTR3(KTR_VFS, "%s: vp %p v_writecount decreased to %d", 545 __func__, vp, vp->v_writecount); 546 } 547 error = VOP_CLOSE(vp, flags, file_cred, td); 548 if (keep_ref) 549 VOP_UNLOCK(vp); 550 else 551 vput(vp); 552 vn_finished_write(mp); 553 return (error); 554 } 555 556 int 557 vn_close(struct vnode *vp, int flags, struct ucred *file_cred, 558 struct thread *td) 559 { 560 561 return (vn_close1(vp, flags, file_cred, td, false)); 562 } 563 564 /* 565 * Heuristic to detect sequential operation. 566 */ 567 static int 568 sequential_heuristic(struct uio *uio, struct file *fp) 569 { 570 enum uio_rw rw; 571 572 ASSERT_VOP_LOCKED(fp->f_vnode, __func__); 573 574 rw = uio->uio_rw; 575 if (fp->f_flag & FRDAHEAD) 576 return (fp->f_seqcount[rw] << IO_SEQSHIFT); 577 578 /* 579 * Offset 0 is handled specially. open() sets f_seqcount to 1 so 580 * that the first I/O is normally considered to be slightly 581 * sequential. Seeking to offset 0 doesn't change sequentiality 582 * unless previous seeks have reduced f_seqcount to 0, in which 583 * case offset 0 is not special. 584 */ 585 if ((uio->uio_offset == 0 && fp->f_seqcount[rw] > 0) || 586 uio->uio_offset == fp->f_nextoff[rw]) { 587 /* 588 * f_seqcount is in units of fixed-size blocks so that it 589 * depends mainly on the amount of sequential I/O and not 590 * much on the number of sequential I/O's. The fixed size 591 * of 16384 is hard-coded here since it is (not quite) just 592 * a magic size that works well here. This size is more 593 * closely related to the best I/O size for real disks than 594 * to any block size used by software. 595 */ 596 if (uio->uio_resid >= IO_SEQMAX * 16384) 597 fp->f_seqcount[rw] = IO_SEQMAX; 598 else { 599 fp->f_seqcount[rw] += howmany(uio->uio_resid, 16384); 600 if (fp->f_seqcount[rw] > IO_SEQMAX) 601 fp->f_seqcount[rw] = IO_SEQMAX; 602 } 603 return (fp->f_seqcount[rw] << IO_SEQSHIFT); 604 } 605 606 /* Not sequential. Quickly draw-down sequentiality. */ 607 if (fp->f_seqcount[rw] > 1) 608 fp->f_seqcount[rw] = 1; 609 else 610 fp->f_seqcount[rw] = 0; 611 return (0); 612 } 613 614 /* 615 * Package up an I/O request on a vnode into a uio and do it. 616 */ 617 int 618 vn_rdwr(enum uio_rw rw, struct vnode *vp, void *base, int len, off_t offset, 619 enum uio_seg segflg, int ioflg, struct ucred *active_cred, 620 struct ucred *file_cred, ssize_t *aresid, struct thread *td) 621 { 622 struct uio auio; 623 struct iovec aiov; 624 struct mount *mp; 625 struct ucred *cred; 626 void *rl_cookie; 627 struct vn_io_fault_args args; 628 int error, lock_flags; 629 630 if (offset < 0 && vp->v_type != VCHR) 631 return (EINVAL); 632 auio.uio_iov = &aiov; 633 auio.uio_iovcnt = 1; 634 aiov.iov_base = base; 635 aiov.iov_len = len; 636 auio.uio_resid = len; 637 auio.uio_offset = offset; 638 auio.uio_segflg = segflg; 639 auio.uio_rw = rw; 640 auio.uio_td = td; 641 error = 0; 642 643 if ((ioflg & IO_NODELOCKED) == 0) { 644 if ((ioflg & IO_RANGELOCKED) == 0) { 645 if (rw == UIO_READ) { 646 rl_cookie = vn_rangelock_rlock(vp, offset, 647 offset + len); 648 } else if ((ioflg & IO_APPEND) != 0) { 649 rl_cookie = vn_rangelock_wlock(vp, 0, OFF_MAX); 650 } else { 651 rl_cookie = vn_rangelock_wlock(vp, offset, 652 offset + len); 653 } 654 } else 655 rl_cookie = NULL; 656 mp = NULL; 657 if (rw == UIO_WRITE) { 658 if (vp->v_type != VCHR && 659 (error = vn_start_write(vp, &mp, V_WAIT | PCATCH)) 660 != 0) 661 goto out; 662 lock_flags = vn_lktype_write(mp, vp); 663 } else 664 lock_flags = LK_SHARED; 665 vn_lock(vp, lock_flags | LK_RETRY); 666 } else 667 rl_cookie = NULL; 668 669 ASSERT_VOP_LOCKED(vp, "IO_NODELOCKED with no vp lock held"); 670 #ifdef MAC 671 if ((ioflg & IO_NOMACCHECK) == 0) { 672 if (rw == UIO_READ) 673 error = mac_vnode_check_read(active_cred, file_cred, 674 vp); 675 else 676 error = mac_vnode_check_write(active_cred, file_cred, 677 vp); 678 } 679 #endif 680 if (error == 0) { 681 if (file_cred != NULL) 682 cred = file_cred; 683 else 684 cred = active_cred; 685 if (do_vn_io_fault(vp, &auio)) { 686 args.kind = VN_IO_FAULT_VOP; 687 args.cred = cred; 688 args.flags = ioflg; 689 args.args.vop_args.vp = vp; 690 error = vn_io_fault1(vp, &auio, &args, td); 691 } else if (rw == UIO_READ) { 692 error = VOP_READ(vp, &auio, ioflg, cred); 693 } else /* if (rw == UIO_WRITE) */ { 694 error = VOP_WRITE(vp, &auio, ioflg, cred); 695 } 696 } 697 if (aresid) 698 *aresid = auio.uio_resid; 699 else 700 if (auio.uio_resid && error == 0) 701 error = EIO; 702 if ((ioflg & IO_NODELOCKED) == 0) { 703 VOP_UNLOCK(vp); 704 if (mp != NULL) 705 vn_finished_write(mp); 706 } 707 out: 708 if (rl_cookie != NULL) 709 vn_rangelock_unlock(vp, rl_cookie); 710 return (error); 711 } 712 713 /* 714 * Package up an I/O request on a vnode into a uio and do it. The I/O 715 * request is split up into smaller chunks and we try to avoid saturating 716 * the buffer cache while potentially holding a vnode locked, so we 717 * check bwillwrite() before calling vn_rdwr(). We also call kern_yield() 718 * to give other processes a chance to lock the vnode (either other processes 719 * core'ing the same binary, or unrelated processes scanning the directory). 720 */ 721 int 722 vn_rdwr_inchunks(enum uio_rw rw, struct vnode *vp, void *base, size_t len, 723 off_t offset, enum uio_seg segflg, int ioflg, struct ucred *active_cred, 724 struct ucred *file_cred, size_t *aresid, struct thread *td) 725 { 726 int error = 0; 727 ssize_t iaresid; 728 729 do { 730 int chunk; 731 732 /* 733 * Force `offset' to a multiple of MAXBSIZE except possibly 734 * for the first chunk, so that filesystems only need to 735 * write full blocks except possibly for the first and last 736 * chunks. 737 */ 738 chunk = MAXBSIZE - (uoff_t)offset % MAXBSIZE; 739 740 if (chunk > len) 741 chunk = len; 742 if (rw != UIO_READ && vp->v_type == VREG) 743 bwillwrite(); 744 iaresid = 0; 745 error = vn_rdwr(rw, vp, base, chunk, offset, segflg, 746 ioflg, active_cred, file_cred, &iaresid, td); 747 len -= chunk; /* aresid calc already includes length */ 748 if (error) 749 break; 750 offset += chunk; 751 base = (char *)base + chunk; 752 kern_yield(PRI_USER); 753 } while (len); 754 if (aresid) 755 *aresid = len + iaresid; 756 return (error); 757 } 758 759 #if OFF_MAX <= LONG_MAX 760 off_t 761 foffset_lock(struct file *fp, int flags) 762 { 763 volatile short *flagsp; 764 off_t res; 765 short state; 766 767 KASSERT((flags & FOF_OFFSET) == 0, ("FOF_OFFSET passed")); 768 769 if ((flags & FOF_NOLOCK) != 0) 770 return (atomic_load_long(&fp->f_offset)); 771 772 /* 773 * According to McKusick the vn lock was protecting f_offset here. 774 * It is now protected by the FOFFSET_LOCKED flag. 775 */ 776 flagsp = &fp->f_vnread_flags; 777 if (atomic_cmpset_acq_16(flagsp, 0, FOFFSET_LOCKED)) 778 return (atomic_load_long(&fp->f_offset)); 779 780 sleepq_lock(&fp->f_vnread_flags); 781 state = atomic_load_16(flagsp); 782 for (;;) { 783 if ((state & FOFFSET_LOCKED) == 0) { 784 if (!atomic_fcmpset_acq_16(flagsp, &state, 785 FOFFSET_LOCKED)) 786 continue; 787 break; 788 } 789 if ((state & FOFFSET_LOCK_WAITING) == 0) { 790 if (!atomic_fcmpset_acq_16(flagsp, &state, 791 state | FOFFSET_LOCK_WAITING)) 792 continue; 793 } 794 DROP_GIANT(); 795 sleepq_add(&fp->f_vnread_flags, NULL, "vofflock", 0, 0); 796 sleepq_wait(&fp->f_vnread_flags, PUSER -1); 797 PICKUP_GIANT(); 798 sleepq_lock(&fp->f_vnread_flags); 799 state = atomic_load_16(flagsp); 800 } 801 res = atomic_load_long(&fp->f_offset); 802 sleepq_release(&fp->f_vnread_flags); 803 return (res); 804 } 805 806 void 807 foffset_unlock(struct file *fp, off_t val, int flags) 808 { 809 volatile short *flagsp; 810 short state; 811 812 KASSERT((flags & FOF_OFFSET) == 0, ("FOF_OFFSET passed")); 813 814 if ((flags & FOF_NOUPDATE) == 0) 815 atomic_store_long(&fp->f_offset, val); 816 if ((flags & FOF_NEXTOFF_R) != 0) 817 fp->f_nextoff[UIO_READ] = val; 818 if ((flags & FOF_NEXTOFF_W) != 0) 819 fp->f_nextoff[UIO_WRITE] = val; 820 821 if ((flags & FOF_NOLOCK) != 0) 822 return; 823 824 flagsp = &fp->f_vnread_flags; 825 state = atomic_load_16(flagsp); 826 if ((state & FOFFSET_LOCK_WAITING) == 0 && 827 atomic_cmpset_rel_16(flagsp, state, 0)) 828 return; 829 830 sleepq_lock(&fp->f_vnread_flags); 831 MPASS((fp->f_vnread_flags & FOFFSET_LOCKED) != 0); 832 MPASS((fp->f_vnread_flags & FOFFSET_LOCK_WAITING) != 0); 833 fp->f_vnread_flags = 0; 834 sleepq_broadcast(&fp->f_vnread_flags, SLEEPQ_SLEEP, 0, 0); 835 sleepq_release(&fp->f_vnread_flags); 836 } 837 #else 838 off_t 839 foffset_lock(struct file *fp, int flags) 840 { 841 struct mtx *mtxp; 842 off_t res; 843 844 KASSERT((flags & FOF_OFFSET) == 0, ("FOF_OFFSET passed")); 845 846 mtxp = mtx_pool_find(mtxpool_sleep, fp); 847 mtx_lock(mtxp); 848 if ((flags & FOF_NOLOCK) == 0) { 849 while (fp->f_vnread_flags & FOFFSET_LOCKED) { 850 fp->f_vnread_flags |= FOFFSET_LOCK_WAITING; 851 msleep(&fp->f_vnread_flags, mtxp, PUSER -1, 852 "vofflock", 0); 853 } 854 fp->f_vnread_flags |= FOFFSET_LOCKED; 855 } 856 res = fp->f_offset; 857 mtx_unlock(mtxp); 858 return (res); 859 } 860 861 void 862 foffset_unlock(struct file *fp, off_t val, int flags) 863 { 864 struct mtx *mtxp; 865 866 KASSERT((flags & FOF_OFFSET) == 0, ("FOF_OFFSET passed")); 867 868 mtxp = mtx_pool_find(mtxpool_sleep, fp); 869 mtx_lock(mtxp); 870 if ((flags & FOF_NOUPDATE) == 0) 871 fp->f_offset = val; 872 if ((flags & FOF_NEXTOFF_R) != 0) 873 fp->f_nextoff[UIO_READ] = val; 874 if ((flags & FOF_NEXTOFF_W) != 0) 875 fp->f_nextoff[UIO_WRITE] = val; 876 if ((flags & FOF_NOLOCK) == 0) { 877 KASSERT((fp->f_vnread_flags & FOFFSET_LOCKED) != 0, 878 ("Lost FOFFSET_LOCKED")); 879 if (fp->f_vnread_flags & FOFFSET_LOCK_WAITING) 880 wakeup(&fp->f_vnread_flags); 881 fp->f_vnread_flags = 0; 882 } 883 mtx_unlock(mtxp); 884 } 885 #endif 886 887 void 888 foffset_lock_uio(struct file *fp, struct uio *uio, int flags) 889 { 890 891 if ((flags & FOF_OFFSET) == 0) 892 uio->uio_offset = foffset_lock(fp, flags); 893 } 894 895 void 896 foffset_unlock_uio(struct file *fp, struct uio *uio, int flags) 897 { 898 899 if ((flags & FOF_OFFSET) == 0) 900 foffset_unlock(fp, uio->uio_offset, flags); 901 } 902 903 static int 904 get_advice(struct file *fp, struct uio *uio) 905 { 906 struct mtx *mtxp; 907 int ret; 908 909 ret = POSIX_FADV_NORMAL; 910 if (fp->f_advice == NULL || fp->f_vnode->v_type != VREG) 911 return (ret); 912 913 mtxp = mtx_pool_find(mtxpool_sleep, fp); 914 mtx_lock(mtxp); 915 if (fp->f_advice != NULL && 916 uio->uio_offset >= fp->f_advice->fa_start && 917 uio->uio_offset + uio->uio_resid <= fp->f_advice->fa_end) 918 ret = fp->f_advice->fa_advice; 919 mtx_unlock(mtxp); 920 return (ret); 921 } 922 923 int 924 vn_read_from_obj(struct vnode *vp, struct uio *uio) 925 { 926 vm_object_t obj; 927 vm_page_t ma[io_hold_cnt + 2]; 928 off_t off, vsz; 929 ssize_t resid; 930 int error, i, j; 931 932 MPASS(uio->uio_resid <= ptoa(io_hold_cnt + 2)); 933 obj = atomic_load_ptr(&vp->v_object); 934 if (obj == NULL) 935 return (EJUSTRETURN); 936 937 /* 938 * Depends on type stability of vm_objects. 939 */ 940 vm_object_pip_add(obj, 1); 941 if ((obj->flags & OBJ_DEAD) != 0) { 942 /* 943 * Note that object might be already reused from the 944 * vnode, and the OBJ_DEAD flag cleared. This is fine, 945 * we recheck for DOOMED vnode state after all pages 946 * are busied, and retract then. 947 * 948 * But we check for OBJ_DEAD to ensure that we do not 949 * busy pages while vm_object_terminate_pages() 950 * processes the queue. 951 */ 952 error = EJUSTRETURN; 953 goto out_pip; 954 } 955 956 resid = uio->uio_resid; 957 off = uio->uio_offset; 958 for (i = 0; resid > 0; i++) { 959 MPASS(i < io_hold_cnt + 2); 960 ma[i] = vm_page_grab_unlocked(obj, atop(off), 961 VM_ALLOC_NOCREAT | VM_ALLOC_SBUSY | VM_ALLOC_IGN_SBUSY | 962 VM_ALLOC_NOWAIT); 963 if (ma[i] == NULL) 964 break; 965 966 /* 967 * Skip invalid pages. Valid mask can be partial only 968 * at EOF, and we clip later. 969 */ 970 if (vm_page_none_valid(ma[i])) { 971 vm_page_sunbusy(ma[i]); 972 break; 973 } 974 975 resid -= PAGE_SIZE; 976 off += PAGE_SIZE; 977 } 978 if (i == 0) { 979 error = EJUSTRETURN; 980 goto out_pip; 981 } 982 983 /* 984 * Check VIRF_DOOMED after we busied our pages. Since 985 * vgonel() terminates the vnode' vm_object, it cannot 986 * process past pages busied by us. 987 */ 988 if (VN_IS_DOOMED(vp)) { 989 error = EJUSTRETURN; 990 goto out; 991 } 992 993 resid = PAGE_SIZE - (uio->uio_offset & PAGE_MASK) + ptoa(i - 1); 994 if (resid > uio->uio_resid) 995 resid = uio->uio_resid; 996 997 /* 998 * Unlocked read of vnp_size is safe because truncation cannot 999 * pass busied page. But we load vnp_size into a local 1000 * variable so that possible concurrent extension does not 1001 * break calculation. 1002 */ 1003 #if defined(__powerpc__) && !defined(__powerpc64__) 1004 vsz = obj->un_pager.vnp.vnp_size; 1005 #else 1006 vsz = atomic_load_64(&obj->un_pager.vnp.vnp_size); 1007 #endif 1008 if (uio->uio_offset >= vsz) { 1009 error = EJUSTRETURN; 1010 goto out; 1011 } 1012 if (uio->uio_offset + resid > vsz) 1013 resid = vsz - uio->uio_offset; 1014 1015 error = vn_io_fault_pgmove(ma, uio->uio_offset & PAGE_MASK, resid, uio); 1016 1017 out: 1018 for (j = 0; j < i; j++) { 1019 if (error == 0) 1020 vm_page_reference(ma[j]); 1021 vm_page_sunbusy(ma[j]); 1022 } 1023 out_pip: 1024 vm_object_pip_wakeup(obj); 1025 if (error != 0) 1026 return (error); 1027 return (uio->uio_resid == 0 ? 0 : EJUSTRETURN); 1028 } 1029 1030 /* 1031 * File table vnode read routine. 1032 */ 1033 static int 1034 vn_read(struct file *fp, struct uio *uio, struct ucred *active_cred, int flags, 1035 struct thread *td) 1036 { 1037 struct vnode *vp; 1038 off_t orig_offset; 1039 int error, ioflag; 1040 int advice; 1041 1042 KASSERT(uio->uio_td == td, ("uio_td %p is not td %p", 1043 uio->uio_td, td)); 1044 KASSERT(flags & FOF_OFFSET, ("No FOF_OFFSET")); 1045 vp = fp->f_vnode; 1046 ioflag = 0; 1047 if (fp->f_flag & FNONBLOCK) 1048 ioflag |= IO_NDELAY; 1049 if (fp->f_flag & O_DIRECT) 1050 ioflag |= IO_DIRECT; 1051 1052 /* 1053 * Try to read from page cache. VIRF_DOOMED check is racy but 1054 * allows us to avoid unneeded work outright. 1055 */ 1056 if (vn_io_pgcache_read_enable && !mac_vnode_check_read_enabled() && 1057 (vn_irflag_read(vp) & (VIRF_DOOMED | VIRF_PGREAD)) == VIRF_PGREAD) { 1058 error = VOP_READ_PGCACHE(vp, uio, ioflag, fp->f_cred); 1059 if (error == 0) { 1060 fp->f_nextoff[UIO_READ] = uio->uio_offset; 1061 return (0); 1062 } 1063 if (error != EJUSTRETURN) 1064 return (error); 1065 } 1066 1067 advice = get_advice(fp, uio); 1068 vn_lock(vp, LK_SHARED | LK_RETRY); 1069 1070 switch (advice) { 1071 case POSIX_FADV_NORMAL: 1072 case POSIX_FADV_SEQUENTIAL: 1073 case POSIX_FADV_NOREUSE: 1074 ioflag |= sequential_heuristic(uio, fp); 1075 break; 1076 case POSIX_FADV_RANDOM: 1077 /* Disable read-ahead for random I/O. */ 1078 break; 1079 } 1080 orig_offset = uio->uio_offset; 1081 1082 #ifdef MAC 1083 error = mac_vnode_check_read(active_cred, fp->f_cred, vp); 1084 if (error == 0) 1085 #endif 1086 error = VOP_READ(vp, uio, ioflag, fp->f_cred); 1087 fp->f_nextoff[UIO_READ] = uio->uio_offset; 1088 VOP_UNLOCK(vp); 1089 if (error == 0 && advice == POSIX_FADV_NOREUSE && 1090 orig_offset != uio->uio_offset) 1091 /* 1092 * Use POSIX_FADV_DONTNEED to flush pages and buffers 1093 * for the backing file after a POSIX_FADV_NOREUSE 1094 * read(2). 1095 */ 1096 error = VOP_ADVISE(vp, orig_offset, uio->uio_offset - 1, 1097 POSIX_FADV_DONTNEED); 1098 return (error); 1099 } 1100 1101 /* 1102 * File table vnode write routine. 1103 */ 1104 static int 1105 vn_write(struct file *fp, struct uio *uio, struct ucred *active_cred, int flags, 1106 struct thread *td) 1107 { 1108 struct vnode *vp; 1109 struct mount *mp; 1110 off_t orig_offset; 1111 int error, ioflag; 1112 int advice; 1113 bool need_finished_write; 1114 1115 KASSERT(uio->uio_td == td, ("uio_td %p is not td %p", 1116 uio->uio_td, td)); 1117 KASSERT(flags & FOF_OFFSET, ("No FOF_OFFSET")); 1118 vp = fp->f_vnode; 1119 if (vp->v_type == VREG) 1120 bwillwrite(); 1121 ioflag = IO_UNIT; 1122 if (vp->v_type == VREG && (fp->f_flag & O_APPEND)) 1123 ioflag |= IO_APPEND; 1124 if (fp->f_flag & FNONBLOCK) 1125 ioflag |= IO_NDELAY; 1126 if (fp->f_flag & O_DIRECT) 1127 ioflag |= IO_DIRECT; 1128 1129 mp = atomic_load_ptr(&vp->v_mount); 1130 if ((fp->f_flag & O_FSYNC) || 1131 (mp != NULL && (mp->mnt_flag & MNT_SYNCHRONOUS))) 1132 ioflag |= IO_SYNC; 1133 1134 /* 1135 * For O_DSYNC we set both IO_SYNC and IO_DATASYNC, so that VOP_WRITE() 1136 * implementations that don't understand IO_DATASYNC fall back to full 1137 * O_SYNC behavior. 1138 */ 1139 if (fp->f_flag & O_DSYNC) 1140 ioflag |= IO_SYNC | IO_DATASYNC; 1141 mp = NULL; 1142 need_finished_write = false; 1143 if (vp->v_type != VCHR) { 1144 error = vn_start_write(vp, &mp, V_WAIT | PCATCH); 1145 if (error != 0) 1146 goto unlock; 1147 need_finished_write = true; 1148 } 1149 1150 advice = get_advice(fp, uio); 1151 1152 vn_lock(vp, vn_lktype_write(mp, vp) | LK_RETRY); 1153 switch (advice) { 1154 case POSIX_FADV_NORMAL: 1155 case POSIX_FADV_SEQUENTIAL: 1156 case POSIX_FADV_NOREUSE: 1157 ioflag |= sequential_heuristic(uio, fp); 1158 break; 1159 case POSIX_FADV_RANDOM: 1160 /* XXX: Is this correct? */ 1161 break; 1162 } 1163 orig_offset = uio->uio_offset; 1164 1165 #ifdef MAC 1166 error = mac_vnode_check_write(active_cred, fp->f_cred, vp); 1167 if (error == 0) 1168 #endif 1169 error = VOP_WRITE(vp, uio, ioflag, fp->f_cred); 1170 fp->f_nextoff[UIO_WRITE] = uio->uio_offset; 1171 VOP_UNLOCK(vp); 1172 if (need_finished_write) 1173 vn_finished_write(mp); 1174 if (error == 0 && advice == POSIX_FADV_NOREUSE && 1175 orig_offset != uio->uio_offset) 1176 /* 1177 * Use POSIX_FADV_DONTNEED to flush pages and buffers 1178 * for the backing file after a POSIX_FADV_NOREUSE 1179 * write(2). 1180 */ 1181 error = VOP_ADVISE(vp, orig_offset, uio->uio_offset - 1, 1182 POSIX_FADV_DONTNEED); 1183 unlock: 1184 return (error); 1185 } 1186 1187 /* 1188 * The vn_io_fault() is a wrapper around vn_read() and vn_write() to 1189 * prevent the following deadlock: 1190 * 1191 * Assume that the thread A reads from the vnode vp1 into userspace 1192 * buffer buf1 backed by the pages of vnode vp2. If a page in buf1 is 1193 * currently not resident, then system ends up with the call chain 1194 * vn_read() -> VOP_READ(vp1) -> uiomove() -> [Page Fault] -> 1195 * vm_fault(buf1) -> vnode_pager_getpages(vp2) -> VOP_GETPAGES(vp2) 1196 * which establishes lock order vp1->vn_lock, then vp2->vn_lock. 1197 * If, at the same time, thread B reads from vnode vp2 into buffer buf2 1198 * backed by the pages of vnode vp1, and some page in buf2 is not 1199 * resident, we get a reversed order vp2->vn_lock, then vp1->vn_lock. 1200 * 1201 * To prevent the lock order reversal and deadlock, vn_io_fault() does 1202 * not allow page faults to happen during VOP_READ() or VOP_WRITE(). 1203 * Instead, it first tries to do the whole range i/o with pagefaults 1204 * disabled. If all pages in the i/o buffer are resident and mapped, 1205 * VOP will succeed (ignoring the genuine filesystem errors). 1206 * Otherwise, we get back EFAULT, and vn_io_fault() falls back to do 1207 * i/o in chunks, with all pages in the chunk prefaulted and held 1208 * using vm_fault_quick_hold_pages(). 1209 * 1210 * Filesystems using this deadlock avoidance scheme should use the 1211 * array of the held pages from uio, saved in the curthread->td_ma, 1212 * instead of doing uiomove(). A helper function 1213 * vn_io_fault_uiomove() converts uiomove request into 1214 * uiomove_fromphys() over td_ma array. 1215 * 1216 * Since vnode locks do not cover the whole i/o anymore, rangelocks 1217 * make the current i/o request atomic with respect to other i/os and 1218 * truncations. 1219 */ 1220 1221 /* 1222 * Decode vn_io_fault_args and perform the corresponding i/o. 1223 */ 1224 static int 1225 vn_io_fault_doio(struct vn_io_fault_args *args, struct uio *uio, 1226 struct thread *td) 1227 { 1228 int error, save; 1229 1230 error = 0; 1231 save = vm_fault_disable_pagefaults(); 1232 switch (args->kind) { 1233 case VN_IO_FAULT_FOP: 1234 error = (args->args.fop_args.doio)(args->args.fop_args.fp, 1235 uio, args->cred, args->flags, td); 1236 break; 1237 case VN_IO_FAULT_VOP: 1238 if (uio->uio_rw == UIO_READ) { 1239 error = VOP_READ(args->args.vop_args.vp, uio, 1240 args->flags, args->cred); 1241 } else if (uio->uio_rw == UIO_WRITE) { 1242 error = VOP_WRITE(args->args.vop_args.vp, uio, 1243 args->flags, args->cred); 1244 } 1245 break; 1246 default: 1247 panic("vn_io_fault_doio: unknown kind of io %d %d", 1248 args->kind, uio->uio_rw); 1249 } 1250 vm_fault_enable_pagefaults(save); 1251 return (error); 1252 } 1253 1254 static int 1255 vn_io_fault_touch(char *base, const struct uio *uio) 1256 { 1257 int r; 1258 1259 r = fubyte(base); 1260 if (r == -1 || (uio->uio_rw == UIO_READ && subyte(base, r) == -1)) 1261 return (EFAULT); 1262 return (0); 1263 } 1264 1265 static int 1266 vn_io_fault_prefault_user(const struct uio *uio) 1267 { 1268 char *base; 1269 const struct iovec *iov; 1270 size_t len; 1271 ssize_t resid; 1272 int error, i; 1273 1274 KASSERT(uio->uio_segflg == UIO_USERSPACE, 1275 ("vn_io_fault_prefault userspace")); 1276 1277 error = i = 0; 1278 iov = uio->uio_iov; 1279 resid = uio->uio_resid; 1280 base = iov->iov_base; 1281 len = iov->iov_len; 1282 while (resid > 0) { 1283 error = vn_io_fault_touch(base, uio); 1284 if (error != 0) 1285 break; 1286 if (len < PAGE_SIZE) { 1287 if (len != 0) { 1288 error = vn_io_fault_touch(base + len - 1, uio); 1289 if (error != 0) 1290 break; 1291 resid -= len; 1292 } 1293 if (++i >= uio->uio_iovcnt) 1294 break; 1295 iov = uio->uio_iov + i; 1296 base = iov->iov_base; 1297 len = iov->iov_len; 1298 } else { 1299 len -= PAGE_SIZE; 1300 base += PAGE_SIZE; 1301 resid -= PAGE_SIZE; 1302 } 1303 } 1304 return (error); 1305 } 1306 1307 /* 1308 * Common code for vn_io_fault(), agnostic to the kind of i/o request. 1309 * Uses vn_io_fault_doio() to make the call to an actual i/o function. 1310 * Used from vn_rdwr() and vn_io_fault(), which encode the i/o request 1311 * into args and call vn_io_fault1() to handle faults during the user 1312 * mode buffer accesses. 1313 */ 1314 static int 1315 vn_io_fault1(struct vnode *vp, struct uio *uio, struct vn_io_fault_args *args, 1316 struct thread *td) 1317 { 1318 vm_page_t ma[io_hold_cnt + 2]; 1319 struct uio *uio_clone, short_uio; 1320 struct iovec short_iovec[1]; 1321 vm_page_t *prev_td_ma; 1322 vm_prot_t prot; 1323 vm_offset_t addr, end; 1324 size_t len, resid; 1325 ssize_t adv; 1326 int error, cnt, saveheld, prev_td_ma_cnt; 1327 1328 if (vn_io_fault_prefault) { 1329 error = vn_io_fault_prefault_user(uio); 1330 if (error != 0) 1331 return (error); /* Or ignore ? */ 1332 } 1333 1334 prot = uio->uio_rw == UIO_READ ? VM_PROT_WRITE : VM_PROT_READ; 1335 1336 /* 1337 * The UFS follows IO_UNIT directive and replays back both 1338 * uio_offset and uio_resid if an error is encountered during the 1339 * operation. But, since the iovec may be already advanced, 1340 * uio is still in an inconsistent state. 1341 * 1342 * Cache a copy of the original uio, which is advanced to the redo 1343 * point using UIO_NOCOPY below. 1344 */ 1345 uio_clone = cloneuio(uio); 1346 resid = uio->uio_resid; 1347 1348 short_uio.uio_segflg = UIO_USERSPACE; 1349 short_uio.uio_rw = uio->uio_rw; 1350 short_uio.uio_td = uio->uio_td; 1351 1352 error = vn_io_fault_doio(args, uio, td); 1353 if (error != EFAULT) 1354 goto out; 1355 1356 atomic_add_long(&vn_io_faults_cnt, 1); 1357 uio_clone->uio_segflg = UIO_NOCOPY; 1358 uiomove(NULL, resid - uio->uio_resid, uio_clone); 1359 uio_clone->uio_segflg = uio->uio_segflg; 1360 1361 saveheld = curthread_pflags_set(TDP_UIOHELD); 1362 prev_td_ma = td->td_ma; 1363 prev_td_ma_cnt = td->td_ma_cnt; 1364 1365 while (uio_clone->uio_resid != 0) { 1366 len = uio_clone->uio_iov->iov_len; 1367 if (len == 0) { 1368 KASSERT(uio_clone->uio_iovcnt >= 1, 1369 ("iovcnt underflow")); 1370 uio_clone->uio_iov++; 1371 uio_clone->uio_iovcnt--; 1372 continue; 1373 } 1374 if (len > ptoa(io_hold_cnt)) 1375 len = ptoa(io_hold_cnt); 1376 addr = (uintptr_t)uio_clone->uio_iov->iov_base; 1377 end = round_page(addr + len); 1378 if (end < addr) { 1379 error = EFAULT; 1380 break; 1381 } 1382 cnt = atop(end - trunc_page(addr)); 1383 /* 1384 * A perfectly misaligned address and length could cause 1385 * both the start and the end of the chunk to use partial 1386 * page. +2 accounts for such a situation. 1387 */ 1388 cnt = vm_fault_quick_hold_pages(&td->td_proc->p_vmspace->vm_map, 1389 addr, len, prot, ma, io_hold_cnt + 2); 1390 if (cnt == -1) { 1391 error = EFAULT; 1392 break; 1393 } 1394 short_uio.uio_iov = &short_iovec[0]; 1395 short_iovec[0].iov_base = (void *)addr; 1396 short_uio.uio_iovcnt = 1; 1397 short_uio.uio_resid = short_iovec[0].iov_len = len; 1398 short_uio.uio_offset = uio_clone->uio_offset; 1399 td->td_ma = ma; 1400 td->td_ma_cnt = cnt; 1401 1402 error = vn_io_fault_doio(args, &short_uio, td); 1403 vm_page_unhold_pages(ma, cnt); 1404 adv = len - short_uio.uio_resid; 1405 1406 uio_clone->uio_iov->iov_base = 1407 (char *)uio_clone->uio_iov->iov_base + adv; 1408 uio_clone->uio_iov->iov_len -= adv; 1409 uio_clone->uio_resid -= adv; 1410 uio_clone->uio_offset += adv; 1411 1412 uio->uio_resid -= adv; 1413 uio->uio_offset += adv; 1414 1415 if (error != 0 || adv == 0) 1416 break; 1417 } 1418 td->td_ma = prev_td_ma; 1419 td->td_ma_cnt = prev_td_ma_cnt; 1420 curthread_pflags_restore(saveheld); 1421 out: 1422 free(uio_clone, M_IOV); 1423 return (error); 1424 } 1425 1426 static int 1427 vn_io_fault(struct file *fp, struct uio *uio, struct ucred *active_cred, 1428 int flags, struct thread *td) 1429 { 1430 fo_rdwr_t *doio; 1431 struct vnode *vp; 1432 void *rl_cookie; 1433 struct vn_io_fault_args args; 1434 int error; 1435 1436 doio = uio->uio_rw == UIO_READ ? vn_read : vn_write; 1437 vp = fp->f_vnode; 1438 1439 /* 1440 * The ability to read(2) on a directory has historically been 1441 * allowed for all users, but this can and has been the source of 1442 * at least one security issue in the past. As such, it is now hidden 1443 * away behind a sysctl for those that actually need it to use it, and 1444 * restricted to root when it's turned on to make it relatively safe to 1445 * leave on for longer sessions of need. 1446 */ 1447 if (vp->v_type == VDIR) { 1448 KASSERT(uio->uio_rw == UIO_READ, 1449 ("illegal write attempted on a directory")); 1450 if (!vfs_allow_read_dir) 1451 return (EISDIR); 1452 if ((error = priv_check(td, PRIV_VFS_READ_DIR)) != 0) 1453 return (EISDIR); 1454 } 1455 1456 foffset_lock_uio(fp, uio, flags); 1457 if (do_vn_io_fault(vp, uio)) { 1458 args.kind = VN_IO_FAULT_FOP; 1459 args.args.fop_args.fp = fp; 1460 args.args.fop_args.doio = doio; 1461 args.cred = active_cred; 1462 args.flags = flags | FOF_OFFSET; 1463 if (uio->uio_rw == UIO_READ) { 1464 rl_cookie = vn_rangelock_rlock(vp, uio->uio_offset, 1465 uio->uio_offset + uio->uio_resid); 1466 } else if ((fp->f_flag & O_APPEND) != 0 || 1467 (flags & FOF_OFFSET) == 0) { 1468 /* For appenders, punt and lock the whole range. */ 1469 rl_cookie = vn_rangelock_wlock(vp, 0, OFF_MAX); 1470 } else { 1471 rl_cookie = vn_rangelock_wlock(vp, uio->uio_offset, 1472 uio->uio_offset + uio->uio_resid); 1473 } 1474 error = vn_io_fault1(vp, uio, &args, td); 1475 vn_rangelock_unlock(vp, rl_cookie); 1476 } else { 1477 error = doio(fp, uio, active_cred, flags | FOF_OFFSET, td); 1478 } 1479 foffset_unlock_uio(fp, uio, flags); 1480 return (error); 1481 } 1482 1483 /* 1484 * Helper function to perform the requested uiomove operation using 1485 * the held pages for io->uio_iov[0].iov_base buffer instead of 1486 * copyin/copyout. Access to the pages with uiomove_fromphys() 1487 * instead of iov_base prevents page faults that could occur due to 1488 * pmap_collect() invalidating the mapping created by 1489 * vm_fault_quick_hold_pages(), or pageout daemon, page laundry or 1490 * object cleanup revoking the write access from page mappings. 1491 * 1492 * Filesystems specified MNTK_NO_IOPF shall use vn_io_fault_uiomove() 1493 * instead of plain uiomove(). 1494 */ 1495 int 1496 vn_io_fault_uiomove(char *data, int xfersize, struct uio *uio) 1497 { 1498 struct uio transp_uio; 1499 struct iovec transp_iov[1]; 1500 struct thread *td; 1501 size_t adv; 1502 int error, pgadv; 1503 1504 td = curthread; 1505 if ((td->td_pflags & TDP_UIOHELD) == 0 || 1506 uio->uio_segflg != UIO_USERSPACE) 1507 return (uiomove(data, xfersize, uio)); 1508 1509 KASSERT(uio->uio_iovcnt == 1, ("uio_iovcnt %d", uio->uio_iovcnt)); 1510 transp_iov[0].iov_base = data; 1511 transp_uio.uio_iov = &transp_iov[0]; 1512 transp_uio.uio_iovcnt = 1; 1513 if (xfersize > uio->uio_resid) 1514 xfersize = uio->uio_resid; 1515 transp_uio.uio_resid = transp_iov[0].iov_len = xfersize; 1516 transp_uio.uio_offset = 0; 1517 transp_uio.uio_segflg = UIO_SYSSPACE; 1518 /* 1519 * Since transp_iov points to data, and td_ma page array 1520 * corresponds to original uio->uio_iov, we need to invert the 1521 * direction of the i/o operation as passed to 1522 * uiomove_fromphys(). 1523 */ 1524 switch (uio->uio_rw) { 1525 case UIO_WRITE: 1526 transp_uio.uio_rw = UIO_READ; 1527 break; 1528 case UIO_READ: 1529 transp_uio.uio_rw = UIO_WRITE; 1530 break; 1531 } 1532 transp_uio.uio_td = uio->uio_td; 1533 error = uiomove_fromphys(td->td_ma, 1534 ((vm_offset_t)uio->uio_iov->iov_base) & PAGE_MASK, 1535 xfersize, &transp_uio); 1536 adv = xfersize - transp_uio.uio_resid; 1537 pgadv = 1538 (((vm_offset_t)uio->uio_iov->iov_base + adv) >> PAGE_SHIFT) - 1539 (((vm_offset_t)uio->uio_iov->iov_base) >> PAGE_SHIFT); 1540 td->td_ma += pgadv; 1541 KASSERT(td->td_ma_cnt >= pgadv, ("consumed pages %d %d", td->td_ma_cnt, 1542 pgadv)); 1543 td->td_ma_cnt -= pgadv; 1544 uio->uio_iov->iov_base = (char *)uio->uio_iov->iov_base + adv; 1545 uio->uio_iov->iov_len -= adv; 1546 uio->uio_resid -= adv; 1547 uio->uio_offset += adv; 1548 return (error); 1549 } 1550 1551 int 1552 vn_io_fault_pgmove(vm_page_t ma[], vm_offset_t offset, int xfersize, 1553 struct uio *uio) 1554 { 1555 struct thread *td; 1556 vm_offset_t iov_base; 1557 int cnt, pgadv; 1558 1559 td = curthread; 1560 if ((td->td_pflags & TDP_UIOHELD) == 0 || 1561 uio->uio_segflg != UIO_USERSPACE) 1562 return (uiomove_fromphys(ma, offset, xfersize, uio)); 1563 1564 KASSERT(uio->uio_iovcnt == 1, ("uio_iovcnt %d", uio->uio_iovcnt)); 1565 cnt = xfersize > uio->uio_resid ? uio->uio_resid : xfersize; 1566 iov_base = (vm_offset_t)uio->uio_iov->iov_base; 1567 switch (uio->uio_rw) { 1568 case UIO_WRITE: 1569 pmap_copy_pages(td->td_ma, iov_base & PAGE_MASK, ma, 1570 offset, cnt); 1571 break; 1572 case UIO_READ: 1573 pmap_copy_pages(ma, offset, td->td_ma, iov_base & PAGE_MASK, 1574 cnt); 1575 break; 1576 } 1577 pgadv = ((iov_base + cnt) >> PAGE_SHIFT) - (iov_base >> PAGE_SHIFT); 1578 td->td_ma += pgadv; 1579 KASSERT(td->td_ma_cnt >= pgadv, ("consumed pages %d %d", td->td_ma_cnt, 1580 pgadv)); 1581 td->td_ma_cnt -= pgadv; 1582 uio->uio_iov->iov_base = (char *)(iov_base + cnt); 1583 uio->uio_iov->iov_len -= cnt; 1584 uio->uio_resid -= cnt; 1585 uio->uio_offset += cnt; 1586 return (0); 1587 } 1588 1589 /* 1590 * File table truncate routine. 1591 */ 1592 static int 1593 vn_truncate(struct file *fp, off_t length, struct ucred *active_cred, 1594 struct thread *td) 1595 { 1596 struct mount *mp; 1597 struct vnode *vp; 1598 void *rl_cookie; 1599 int error; 1600 1601 vp = fp->f_vnode; 1602 1603 retry: 1604 /* 1605 * Lock the whole range for truncation. Otherwise split i/o 1606 * might happen partly before and partly after the truncation. 1607 */ 1608 rl_cookie = vn_rangelock_wlock(vp, 0, OFF_MAX); 1609 error = vn_start_write(vp, &mp, V_WAIT | PCATCH); 1610 if (error) 1611 goto out1; 1612 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 1613 AUDIT_ARG_VNODE1(vp); 1614 if (vp->v_type == VDIR) { 1615 error = EISDIR; 1616 goto out; 1617 } 1618 #ifdef MAC 1619 error = mac_vnode_check_write(active_cred, fp->f_cred, vp); 1620 if (error) 1621 goto out; 1622 #endif 1623 error = vn_truncate_locked(vp, length, (fp->f_flag & O_FSYNC) != 0, 1624 fp->f_cred); 1625 out: 1626 VOP_UNLOCK(vp); 1627 vn_finished_write(mp); 1628 out1: 1629 vn_rangelock_unlock(vp, rl_cookie); 1630 if (error == ERELOOKUP) 1631 goto retry; 1632 return (error); 1633 } 1634 1635 /* 1636 * Truncate a file that is already locked. 1637 */ 1638 int 1639 vn_truncate_locked(struct vnode *vp, off_t length, bool sync, 1640 struct ucred *cred) 1641 { 1642 struct vattr vattr; 1643 int error; 1644 1645 error = VOP_ADD_WRITECOUNT(vp, 1); 1646 if (error == 0) { 1647 VATTR_NULL(&vattr); 1648 vattr.va_size = length; 1649 if (sync) 1650 vattr.va_vaflags |= VA_SYNC; 1651 error = VOP_SETATTR(vp, &vattr, cred); 1652 VOP_ADD_WRITECOUNT_CHECKED(vp, -1); 1653 } 1654 return (error); 1655 } 1656 1657 /* 1658 * File table vnode stat routine. 1659 */ 1660 int 1661 vn_statfile(struct file *fp, struct stat *sb, struct ucred *active_cred, 1662 struct thread *td) 1663 { 1664 struct vnode *vp = fp->f_vnode; 1665 int error; 1666 1667 vn_lock(vp, LK_SHARED | LK_RETRY); 1668 error = VOP_STAT(vp, sb, active_cred, fp->f_cred, td); 1669 VOP_UNLOCK(vp); 1670 1671 return (error); 1672 } 1673 1674 /* 1675 * File table vnode ioctl routine. 1676 */ 1677 static int 1678 vn_ioctl(struct file *fp, u_long com, void *data, struct ucred *active_cred, 1679 struct thread *td) 1680 { 1681 struct vattr vattr; 1682 struct vnode *vp; 1683 struct fiobmap2_arg *bmarg; 1684 int error; 1685 1686 vp = fp->f_vnode; 1687 switch (vp->v_type) { 1688 case VDIR: 1689 case VREG: 1690 switch (com) { 1691 case FIONREAD: 1692 vn_lock(vp, LK_SHARED | LK_RETRY); 1693 error = VOP_GETATTR(vp, &vattr, active_cred); 1694 VOP_UNLOCK(vp); 1695 if (error == 0) 1696 *(int *)data = vattr.va_size - fp->f_offset; 1697 return (error); 1698 case FIOBMAP2: 1699 bmarg = (struct fiobmap2_arg *)data; 1700 vn_lock(vp, LK_SHARED | LK_RETRY); 1701 #ifdef MAC 1702 error = mac_vnode_check_read(active_cred, fp->f_cred, 1703 vp); 1704 if (error == 0) 1705 #endif 1706 error = VOP_BMAP(vp, bmarg->bn, NULL, 1707 &bmarg->bn, &bmarg->runp, &bmarg->runb); 1708 VOP_UNLOCK(vp); 1709 return (error); 1710 case FIONBIO: 1711 case FIOASYNC: 1712 return (0); 1713 default: 1714 return (VOP_IOCTL(vp, com, data, fp->f_flag, 1715 active_cred, td)); 1716 } 1717 break; 1718 case VCHR: 1719 return (VOP_IOCTL(vp, com, data, fp->f_flag, 1720 active_cred, td)); 1721 default: 1722 return (ENOTTY); 1723 } 1724 } 1725 1726 /* 1727 * File table vnode poll routine. 1728 */ 1729 static int 1730 vn_poll(struct file *fp, int events, struct ucred *active_cred, 1731 struct thread *td) 1732 { 1733 struct vnode *vp; 1734 int error; 1735 1736 vp = fp->f_vnode; 1737 #if defined(MAC) || defined(AUDIT) 1738 if (AUDITING_TD(td) || mac_vnode_check_poll_enabled()) { 1739 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 1740 AUDIT_ARG_VNODE1(vp); 1741 error = mac_vnode_check_poll(active_cred, fp->f_cred, vp); 1742 VOP_UNLOCK(vp); 1743 if (error != 0) 1744 return (error); 1745 } 1746 #endif 1747 error = VOP_POLL(vp, events, fp->f_cred, td); 1748 return (error); 1749 } 1750 1751 /* 1752 * Acquire the requested lock and then check for validity. LK_RETRY 1753 * permits vn_lock to return doomed vnodes. 1754 */ 1755 static int __noinline 1756 _vn_lock_fallback(struct vnode *vp, int flags, const char *file, int line, 1757 int error) 1758 { 1759 1760 KASSERT((flags & LK_RETRY) == 0 || error == 0, 1761 ("vn_lock: error %d incompatible with flags %#x", error, flags)); 1762 1763 if (error == 0) 1764 VNASSERT(VN_IS_DOOMED(vp), vp, ("vnode not doomed")); 1765 1766 if ((flags & LK_RETRY) == 0) { 1767 if (error == 0) { 1768 VOP_UNLOCK(vp); 1769 error = ENOENT; 1770 } 1771 return (error); 1772 } 1773 1774 /* 1775 * LK_RETRY case. 1776 * 1777 * Nothing to do if we got the lock. 1778 */ 1779 if (error == 0) 1780 return (0); 1781 1782 /* 1783 * Interlock was dropped by the call in _vn_lock. 1784 */ 1785 flags &= ~LK_INTERLOCK; 1786 do { 1787 error = VOP_LOCK1(vp, flags, file, line); 1788 } while (error != 0); 1789 return (0); 1790 } 1791 1792 int 1793 _vn_lock(struct vnode *vp, int flags, const char *file, int line) 1794 { 1795 int error; 1796 1797 VNASSERT((flags & LK_TYPE_MASK) != 0, vp, 1798 ("vn_lock: no locktype (%d passed)", flags)); 1799 VNPASS(vp->v_holdcnt > 0, vp); 1800 error = VOP_LOCK1(vp, flags, file, line); 1801 if (__predict_false(error != 0 || VN_IS_DOOMED(vp))) 1802 return (_vn_lock_fallback(vp, flags, file, line, error)); 1803 return (0); 1804 } 1805 1806 /* 1807 * File table vnode close routine. 1808 */ 1809 static int 1810 vn_closefile(struct file *fp, struct thread *td) 1811 { 1812 struct vnode *vp; 1813 struct flock lf; 1814 int error; 1815 bool ref; 1816 1817 vp = fp->f_vnode; 1818 fp->f_ops = &badfileops; 1819 ref = (fp->f_flag & FHASLOCK) != 0 && fp->f_type == DTYPE_VNODE; 1820 1821 error = vn_close1(vp, fp->f_flag, fp->f_cred, td, ref); 1822 1823 if (__predict_false(ref)) { 1824 lf.l_whence = SEEK_SET; 1825 lf.l_start = 0; 1826 lf.l_len = 0; 1827 lf.l_type = F_UNLCK; 1828 (void) VOP_ADVLOCK(vp, fp, F_UNLCK, &lf, F_FLOCK); 1829 vrele(vp); 1830 } 1831 return (error); 1832 } 1833 1834 /* 1835 * Preparing to start a filesystem write operation. If the operation is 1836 * permitted, then we bump the count of operations in progress and 1837 * proceed. If a suspend request is in progress, we wait until the 1838 * suspension is over, and then proceed. 1839 */ 1840 static int 1841 vn_start_write_refed(struct mount *mp, int flags, bool mplocked) 1842 { 1843 struct mount_pcpu *mpcpu; 1844 int error, mflags; 1845 1846 if (__predict_true(!mplocked) && (flags & V_XSLEEP) == 0 && 1847 vfs_op_thread_enter(mp, mpcpu)) { 1848 MPASS((mp->mnt_kern_flag & MNTK_SUSPEND) == 0); 1849 vfs_mp_count_add_pcpu(mpcpu, writeopcount, 1); 1850 vfs_op_thread_exit(mp, mpcpu); 1851 return (0); 1852 } 1853 1854 if (mplocked) 1855 mtx_assert(MNT_MTX(mp), MA_OWNED); 1856 else 1857 MNT_ILOCK(mp); 1858 1859 error = 0; 1860 1861 /* 1862 * Check on status of suspension. 1863 */ 1864 if ((curthread->td_pflags & TDP_IGNSUSP) == 0 || 1865 mp->mnt_susp_owner != curthread) { 1866 mflags = ((mp->mnt_vfc->vfc_flags & VFCF_SBDRY) != 0 ? 1867 (flags & PCATCH) : 0) | (PUSER - 1); 1868 while ((mp->mnt_kern_flag & MNTK_SUSPEND) != 0) { 1869 if (flags & V_NOWAIT) { 1870 error = EWOULDBLOCK; 1871 goto unlock; 1872 } 1873 error = msleep(&mp->mnt_flag, MNT_MTX(mp), mflags, 1874 "suspfs", 0); 1875 if (error) 1876 goto unlock; 1877 } 1878 } 1879 if (flags & V_XSLEEP) 1880 goto unlock; 1881 mp->mnt_writeopcount++; 1882 unlock: 1883 if (error != 0 || (flags & V_XSLEEP) != 0) 1884 MNT_REL(mp); 1885 MNT_IUNLOCK(mp); 1886 return (error); 1887 } 1888 1889 int 1890 vn_start_write(struct vnode *vp, struct mount **mpp, int flags) 1891 { 1892 struct mount *mp; 1893 int error; 1894 1895 KASSERT((flags & V_MNTREF) == 0 || (*mpp != NULL && vp == NULL), 1896 ("V_MNTREF requires mp")); 1897 1898 error = 0; 1899 /* 1900 * If a vnode is provided, get and return the mount point that 1901 * to which it will write. 1902 */ 1903 if (vp != NULL) { 1904 if ((error = VOP_GETWRITEMOUNT(vp, mpp)) != 0) { 1905 *mpp = NULL; 1906 if (error != EOPNOTSUPP) 1907 return (error); 1908 return (0); 1909 } 1910 } 1911 if ((mp = *mpp) == NULL) 1912 return (0); 1913 1914 /* 1915 * VOP_GETWRITEMOUNT() returns with the mp refcount held through 1916 * a vfs_ref(). 1917 * As long as a vnode is not provided we need to acquire a 1918 * refcount for the provided mountpoint too, in order to 1919 * emulate a vfs_ref(). 1920 */ 1921 if (vp == NULL && (flags & V_MNTREF) == 0) 1922 vfs_ref(mp); 1923 1924 return (vn_start_write_refed(mp, flags, false)); 1925 } 1926 1927 /* 1928 * Secondary suspension. Used by operations such as vop_inactive 1929 * routines that are needed by the higher level functions. These 1930 * are allowed to proceed until all the higher level functions have 1931 * completed (indicated by mnt_writeopcount dropping to zero). At that 1932 * time, these operations are halted until the suspension is over. 1933 */ 1934 int 1935 vn_start_secondary_write(struct vnode *vp, struct mount **mpp, int flags) 1936 { 1937 struct mount *mp; 1938 int error; 1939 1940 KASSERT((flags & V_MNTREF) == 0 || (*mpp != NULL && vp == NULL), 1941 ("V_MNTREF requires mp")); 1942 1943 retry: 1944 if (vp != NULL) { 1945 if ((error = VOP_GETWRITEMOUNT(vp, mpp)) != 0) { 1946 *mpp = NULL; 1947 if (error != EOPNOTSUPP) 1948 return (error); 1949 return (0); 1950 } 1951 } 1952 /* 1953 * If we are not suspended or have not yet reached suspended 1954 * mode, then let the operation proceed. 1955 */ 1956 if ((mp = *mpp) == NULL) 1957 return (0); 1958 1959 /* 1960 * VOP_GETWRITEMOUNT() returns with the mp refcount held through 1961 * a vfs_ref(). 1962 * As long as a vnode is not provided we need to acquire a 1963 * refcount for the provided mountpoint too, in order to 1964 * emulate a vfs_ref(). 1965 */ 1966 MNT_ILOCK(mp); 1967 if (vp == NULL && (flags & V_MNTREF) == 0) 1968 MNT_REF(mp); 1969 if ((mp->mnt_kern_flag & (MNTK_SUSPENDED | MNTK_SUSPEND2)) == 0) { 1970 mp->mnt_secondary_writes++; 1971 mp->mnt_secondary_accwrites++; 1972 MNT_IUNLOCK(mp); 1973 return (0); 1974 } 1975 if (flags & V_NOWAIT) { 1976 MNT_REL(mp); 1977 MNT_IUNLOCK(mp); 1978 return (EWOULDBLOCK); 1979 } 1980 /* 1981 * Wait for the suspension to finish. 1982 */ 1983 error = msleep(&mp->mnt_flag, MNT_MTX(mp), (PUSER - 1) | PDROP | 1984 ((mp->mnt_vfc->vfc_flags & VFCF_SBDRY) != 0 ? (flags & PCATCH) : 0), 1985 "suspfs", 0); 1986 vfs_rel(mp); 1987 if (error == 0) 1988 goto retry; 1989 return (error); 1990 } 1991 1992 /* 1993 * Filesystem write operation has completed. If we are suspending and this 1994 * operation is the last one, notify the suspender that the suspension is 1995 * now in effect. 1996 */ 1997 void 1998 vn_finished_write(struct mount *mp) 1999 { 2000 struct mount_pcpu *mpcpu; 2001 int c; 2002 2003 if (mp == NULL) 2004 return; 2005 2006 if (vfs_op_thread_enter(mp, mpcpu)) { 2007 vfs_mp_count_sub_pcpu(mpcpu, writeopcount, 1); 2008 vfs_mp_count_sub_pcpu(mpcpu, ref, 1); 2009 vfs_op_thread_exit(mp, mpcpu); 2010 return; 2011 } 2012 2013 MNT_ILOCK(mp); 2014 vfs_assert_mount_counters(mp); 2015 MNT_REL(mp); 2016 c = --mp->mnt_writeopcount; 2017 if (mp->mnt_vfs_ops == 0) { 2018 MPASS((mp->mnt_kern_flag & MNTK_SUSPEND) == 0); 2019 MNT_IUNLOCK(mp); 2020 return; 2021 } 2022 if (c < 0) 2023 vfs_dump_mount_counters(mp); 2024 if ((mp->mnt_kern_flag & MNTK_SUSPEND) != 0 && c == 0) 2025 wakeup(&mp->mnt_writeopcount); 2026 MNT_IUNLOCK(mp); 2027 } 2028 2029 /* 2030 * Filesystem secondary write operation has completed. If we are 2031 * suspending and this operation is the last one, notify the suspender 2032 * that the suspension is now in effect. 2033 */ 2034 void 2035 vn_finished_secondary_write(struct mount *mp) 2036 { 2037 if (mp == NULL) 2038 return; 2039 MNT_ILOCK(mp); 2040 MNT_REL(mp); 2041 mp->mnt_secondary_writes--; 2042 if (mp->mnt_secondary_writes < 0) 2043 panic("vn_finished_secondary_write: neg cnt"); 2044 if ((mp->mnt_kern_flag & MNTK_SUSPEND) != 0 && 2045 mp->mnt_secondary_writes <= 0) 2046 wakeup(&mp->mnt_secondary_writes); 2047 MNT_IUNLOCK(mp); 2048 } 2049 2050 /* 2051 * Request a filesystem to suspend write operations. 2052 */ 2053 int 2054 vfs_write_suspend(struct mount *mp, int flags) 2055 { 2056 int error; 2057 2058 vfs_op_enter(mp); 2059 2060 MNT_ILOCK(mp); 2061 vfs_assert_mount_counters(mp); 2062 if (mp->mnt_susp_owner == curthread) { 2063 vfs_op_exit_locked(mp); 2064 MNT_IUNLOCK(mp); 2065 return (EALREADY); 2066 } 2067 while (mp->mnt_kern_flag & MNTK_SUSPEND) 2068 msleep(&mp->mnt_flag, MNT_MTX(mp), PUSER - 1, "wsuspfs", 0); 2069 2070 /* 2071 * Unmount holds a write reference on the mount point. If we 2072 * own busy reference and drain for writers, we deadlock with 2073 * the reference draining in the unmount path. Callers of 2074 * vfs_write_suspend() must specify VS_SKIP_UNMOUNT if 2075 * vfs_busy() reference is owned and caller is not in the 2076 * unmount context. 2077 */ 2078 if ((flags & VS_SKIP_UNMOUNT) != 0 && 2079 (mp->mnt_kern_flag & MNTK_UNMOUNT) != 0) { 2080 vfs_op_exit_locked(mp); 2081 MNT_IUNLOCK(mp); 2082 return (EBUSY); 2083 } 2084 2085 mp->mnt_kern_flag |= MNTK_SUSPEND; 2086 mp->mnt_susp_owner = curthread; 2087 if (mp->mnt_writeopcount > 0) 2088 (void) msleep(&mp->mnt_writeopcount, 2089 MNT_MTX(mp), (PUSER - 1)|PDROP, "suspwt", 0); 2090 else 2091 MNT_IUNLOCK(mp); 2092 if ((error = VFS_SYNC(mp, MNT_SUSPEND)) != 0) { 2093 vfs_write_resume(mp, 0); 2094 /* vfs_write_resume does vfs_op_exit() for us */ 2095 } 2096 return (error); 2097 } 2098 2099 /* 2100 * Request a filesystem to resume write operations. 2101 */ 2102 void 2103 vfs_write_resume(struct mount *mp, int flags) 2104 { 2105 2106 MNT_ILOCK(mp); 2107 if ((mp->mnt_kern_flag & MNTK_SUSPEND) != 0) { 2108 KASSERT(mp->mnt_susp_owner == curthread, ("mnt_susp_owner")); 2109 mp->mnt_kern_flag &= ~(MNTK_SUSPEND | MNTK_SUSPEND2 | 2110 MNTK_SUSPENDED); 2111 mp->mnt_susp_owner = NULL; 2112 wakeup(&mp->mnt_writeopcount); 2113 wakeup(&mp->mnt_flag); 2114 curthread->td_pflags &= ~TDP_IGNSUSP; 2115 if ((flags & VR_START_WRITE) != 0) { 2116 MNT_REF(mp); 2117 mp->mnt_writeopcount++; 2118 } 2119 MNT_IUNLOCK(mp); 2120 if ((flags & VR_NO_SUSPCLR) == 0) 2121 VFS_SUSP_CLEAN(mp); 2122 vfs_op_exit(mp); 2123 } else if ((flags & VR_START_WRITE) != 0) { 2124 MNT_REF(mp); 2125 vn_start_write_refed(mp, 0, true); 2126 } else { 2127 MNT_IUNLOCK(mp); 2128 } 2129 } 2130 2131 /* 2132 * Helper loop around vfs_write_suspend() for filesystem unmount VFS 2133 * methods. 2134 */ 2135 int 2136 vfs_write_suspend_umnt(struct mount *mp) 2137 { 2138 int error; 2139 2140 KASSERT((curthread->td_pflags & TDP_IGNSUSP) == 0, 2141 ("vfs_write_suspend_umnt: recursed")); 2142 2143 /* dounmount() already called vn_start_write(). */ 2144 for (;;) { 2145 vn_finished_write(mp); 2146 error = vfs_write_suspend(mp, 0); 2147 if (error != 0) { 2148 vn_start_write(NULL, &mp, V_WAIT); 2149 return (error); 2150 } 2151 MNT_ILOCK(mp); 2152 if ((mp->mnt_kern_flag & MNTK_SUSPENDED) != 0) 2153 break; 2154 MNT_IUNLOCK(mp); 2155 vn_start_write(NULL, &mp, V_WAIT); 2156 } 2157 mp->mnt_kern_flag &= ~(MNTK_SUSPENDED | MNTK_SUSPEND2); 2158 wakeup(&mp->mnt_flag); 2159 MNT_IUNLOCK(mp); 2160 curthread->td_pflags |= TDP_IGNSUSP; 2161 return (0); 2162 } 2163 2164 /* 2165 * Implement kqueues for files by translating it to vnode operation. 2166 */ 2167 static int 2168 vn_kqfilter(struct file *fp, struct knote *kn) 2169 { 2170 2171 return (VOP_KQFILTER(fp->f_vnode, kn)); 2172 } 2173 2174 int 2175 vn_kqfilter_opath(struct file *fp, struct knote *kn) 2176 { 2177 if ((fp->f_flag & FKQALLOWED) == 0) 2178 return (EBADF); 2179 return (vn_kqfilter(fp, kn)); 2180 } 2181 2182 /* 2183 * Simplified in-kernel wrapper calls for extended attribute access. 2184 * Both calls pass in a NULL credential, authorizing as "kernel" access. 2185 * Set IO_NODELOCKED in ioflg if the vnode is already locked. 2186 */ 2187 int 2188 vn_extattr_get(struct vnode *vp, int ioflg, int attrnamespace, 2189 const char *attrname, int *buflen, char *buf, struct thread *td) 2190 { 2191 struct uio auio; 2192 struct iovec iov; 2193 int error; 2194 2195 iov.iov_len = *buflen; 2196 iov.iov_base = buf; 2197 2198 auio.uio_iov = &iov; 2199 auio.uio_iovcnt = 1; 2200 auio.uio_rw = UIO_READ; 2201 auio.uio_segflg = UIO_SYSSPACE; 2202 auio.uio_td = td; 2203 auio.uio_offset = 0; 2204 auio.uio_resid = *buflen; 2205 2206 if ((ioflg & IO_NODELOCKED) == 0) 2207 vn_lock(vp, LK_SHARED | LK_RETRY); 2208 2209 ASSERT_VOP_LOCKED(vp, "IO_NODELOCKED with no vp lock held"); 2210 2211 /* authorize attribute retrieval as kernel */ 2212 error = VOP_GETEXTATTR(vp, attrnamespace, attrname, &auio, NULL, NULL, 2213 td); 2214 2215 if ((ioflg & IO_NODELOCKED) == 0) 2216 VOP_UNLOCK(vp); 2217 2218 if (error == 0) { 2219 *buflen = *buflen - auio.uio_resid; 2220 } 2221 2222 return (error); 2223 } 2224 2225 /* 2226 * XXX failure mode if partially written? 2227 */ 2228 int 2229 vn_extattr_set(struct vnode *vp, int ioflg, int attrnamespace, 2230 const char *attrname, int buflen, char *buf, struct thread *td) 2231 { 2232 struct uio auio; 2233 struct iovec iov; 2234 struct mount *mp; 2235 int error; 2236 2237 iov.iov_len = buflen; 2238 iov.iov_base = buf; 2239 2240 auio.uio_iov = &iov; 2241 auio.uio_iovcnt = 1; 2242 auio.uio_rw = UIO_WRITE; 2243 auio.uio_segflg = UIO_SYSSPACE; 2244 auio.uio_td = td; 2245 auio.uio_offset = 0; 2246 auio.uio_resid = buflen; 2247 2248 if ((ioflg & IO_NODELOCKED) == 0) { 2249 if ((error = vn_start_write(vp, &mp, V_WAIT)) != 0) 2250 return (error); 2251 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 2252 } 2253 2254 ASSERT_VOP_LOCKED(vp, "IO_NODELOCKED with no vp lock held"); 2255 2256 /* authorize attribute setting as kernel */ 2257 error = VOP_SETEXTATTR(vp, attrnamespace, attrname, &auio, NULL, td); 2258 2259 if ((ioflg & IO_NODELOCKED) == 0) { 2260 vn_finished_write(mp); 2261 VOP_UNLOCK(vp); 2262 } 2263 2264 return (error); 2265 } 2266 2267 int 2268 vn_extattr_rm(struct vnode *vp, int ioflg, int attrnamespace, 2269 const char *attrname, struct thread *td) 2270 { 2271 struct mount *mp; 2272 int error; 2273 2274 if ((ioflg & IO_NODELOCKED) == 0) { 2275 if ((error = vn_start_write(vp, &mp, V_WAIT)) != 0) 2276 return (error); 2277 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 2278 } 2279 2280 ASSERT_VOP_LOCKED(vp, "IO_NODELOCKED with no vp lock held"); 2281 2282 /* authorize attribute removal as kernel */ 2283 error = VOP_DELETEEXTATTR(vp, attrnamespace, attrname, NULL, td); 2284 if (error == EOPNOTSUPP) 2285 error = VOP_SETEXTATTR(vp, attrnamespace, attrname, NULL, 2286 NULL, td); 2287 2288 if ((ioflg & IO_NODELOCKED) == 0) { 2289 vn_finished_write(mp); 2290 VOP_UNLOCK(vp); 2291 } 2292 2293 return (error); 2294 } 2295 2296 static int 2297 vn_get_ino_alloc_vget(struct mount *mp, void *arg, int lkflags, 2298 struct vnode **rvp) 2299 { 2300 2301 return (VFS_VGET(mp, *(ino_t *)arg, lkflags, rvp)); 2302 } 2303 2304 int 2305 vn_vget_ino(struct vnode *vp, ino_t ino, int lkflags, struct vnode **rvp) 2306 { 2307 2308 return (vn_vget_ino_gen(vp, vn_get_ino_alloc_vget, &ino, 2309 lkflags, rvp)); 2310 } 2311 2312 int 2313 vn_vget_ino_gen(struct vnode *vp, vn_get_ino_t alloc, void *alloc_arg, 2314 int lkflags, struct vnode **rvp) 2315 { 2316 struct mount *mp; 2317 int ltype, error; 2318 2319 ASSERT_VOP_LOCKED(vp, "vn_vget_ino_get"); 2320 mp = vp->v_mount; 2321 ltype = VOP_ISLOCKED(vp); 2322 KASSERT(ltype == LK_EXCLUSIVE || ltype == LK_SHARED, 2323 ("vn_vget_ino: vp not locked")); 2324 error = vfs_busy(mp, MBF_NOWAIT); 2325 if (error != 0) { 2326 vfs_ref(mp); 2327 VOP_UNLOCK(vp); 2328 error = vfs_busy(mp, 0); 2329 vn_lock(vp, ltype | LK_RETRY); 2330 vfs_rel(mp); 2331 if (error != 0) 2332 return (ENOENT); 2333 if (VN_IS_DOOMED(vp)) { 2334 vfs_unbusy(mp); 2335 return (ENOENT); 2336 } 2337 } 2338 VOP_UNLOCK(vp); 2339 error = alloc(mp, alloc_arg, lkflags, rvp); 2340 vfs_unbusy(mp); 2341 if (error != 0 || *rvp != vp) 2342 vn_lock(vp, ltype | LK_RETRY); 2343 if (VN_IS_DOOMED(vp)) { 2344 if (error == 0) { 2345 if (*rvp == vp) 2346 vunref(vp); 2347 else 2348 vput(*rvp); 2349 } 2350 error = ENOENT; 2351 } 2352 return (error); 2353 } 2354 2355 int 2356 vn_rlimit_fsize(const struct vnode *vp, const struct uio *uio, 2357 struct thread *td) 2358 { 2359 off_t lim; 2360 bool ktr_write; 2361 2362 if (td == NULL) 2363 return (0); 2364 2365 /* 2366 * There are conditions where the limit is to be ignored. 2367 * However, since it is almost never reached, check it first. 2368 */ 2369 ktr_write = (td->td_pflags & TDP_INKTRACE) != 0; 2370 lim = lim_cur(td, RLIMIT_FSIZE); 2371 if (__predict_false(ktr_write)) 2372 lim = td->td_ktr_io_lim; 2373 if (__predict_true((uoff_t)uio->uio_offset + uio->uio_resid <= lim)) 2374 return (0); 2375 2376 /* 2377 * The limit is reached. 2378 */ 2379 if (vp->v_type != VREG || 2380 (td->td_pflags2 & TDP2_ACCT) != 0) 2381 return (0); 2382 2383 if (!ktr_write || ktr_filesize_limit_signal) { 2384 PROC_LOCK(td->td_proc); 2385 kern_psignal(td->td_proc, SIGXFSZ); 2386 PROC_UNLOCK(td->td_proc); 2387 } 2388 return (EFBIG); 2389 } 2390 2391 int 2392 vn_chmod(struct file *fp, mode_t mode, struct ucred *active_cred, 2393 struct thread *td) 2394 { 2395 struct vnode *vp; 2396 2397 vp = fp->f_vnode; 2398 #ifdef AUDIT 2399 vn_lock(vp, LK_SHARED | LK_RETRY); 2400 AUDIT_ARG_VNODE1(vp); 2401 VOP_UNLOCK(vp); 2402 #endif 2403 return (setfmode(td, active_cred, vp, mode)); 2404 } 2405 2406 int 2407 vn_chown(struct file *fp, uid_t uid, gid_t gid, struct ucred *active_cred, 2408 struct thread *td) 2409 { 2410 struct vnode *vp; 2411 2412 vp = fp->f_vnode; 2413 #ifdef AUDIT 2414 vn_lock(vp, LK_SHARED | LK_RETRY); 2415 AUDIT_ARG_VNODE1(vp); 2416 VOP_UNLOCK(vp); 2417 #endif 2418 return (setfown(td, active_cred, vp, uid, gid)); 2419 } 2420 2421 void 2422 vn_pages_remove(struct vnode *vp, vm_pindex_t start, vm_pindex_t end) 2423 { 2424 vm_object_t object; 2425 2426 if ((object = vp->v_object) == NULL) 2427 return; 2428 VM_OBJECT_WLOCK(object); 2429 vm_object_page_remove(object, start, end, 0); 2430 VM_OBJECT_WUNLOCK(object); 2431 } 2432 2433 int 2434 vn_bmap_seekhole_locked(struct vnode *vp, u_long cmd, off_t *off, 2435 struct ucred *cred) 2436 { 2437 struct vattr va; 2438 daddr_t bn, bnp; 2439 uint64_t bsize; 2440 off_t noff; 2441 int error; 2442 2443 KASSERT(cmd == FIOSEEKHOLE || cmd == FIOSEEKDATA, 2444 ("%s: Wrong command %lu", __func__, cmd)); 2445 ASSERT_VOP_LOCKED(vp, "vn_bmap_seekhole_locked"); 2446 2447 if (vp->v_type != VREG) { 2448 error = ENOTTY; 2449 goto out; 2450 } 2451 error = VOP_GETATTR(vp, &va, cred); 2452 if (error != 0) 2453 goto out; 2454 noff = *off; 2455 if (noff >= va.va_size) { 2456 error = ENXIO; 2457 goto out; 2458 } 2459 bsize = vp->v_mount->mnt_stat.f_iosize; 2460 for (bn = noff / bsize; noff < va.va_size; bn++, noff += bsize - 2461 noff % bsize) { 2462 error = VOP_BMAP(vp, bn, NULL, &bnp, NULL, NULL); 2463 if (error == EOPNOTSUPP) { 2464 error = ENOTTY; 2465 goto out; 2466 } 2467 if ((bnp == -1 && cmd == FIOSEEKHOLE) || 2468 (bnp != -1 && cmd == FIOSEEKDATA)) { 2469 noff = bn * bsize; 2470 if (noff < *off) 2471 noff = *off; 2472 goto out; 2473 } 2474 } 2475 if (noff > va.va_size) 2476 noff = va.va_size; 2477 /* noff == va.va_size. There is an implicit hole at the end of file. */ 2478 if (cmd == FIOSEEKDATA) 2479 error = ENXIO; 2480 out: 2481 if (error == 0) 2482 *off = noff; 2483 return (error); 2484 } 2485 2486 int 2487 vn_bmap_seekhole(struct vnode *vp, u_long cmd, off_t *off, struct ucred *cred) 2488 { 2489 int error; 2490 2491 KASSERT(cmd == FIOSEEKHOLE || cmd == FIOSEEKDATA, 2492 ("%s: Wrong command %lu", __func__, cmd)); 2493 2494 if (vn_lock(vp, LK_SHARED) != 0) 2495 return (EBADF); 2496 error = vn_bmap_seekhole_locked(vp, cmd, off, cred); 2497 VOP_UNLOCK(vp); 2498 return (error); 2499 } 2500 2501 int 2502 vn_seek(struct file *fp, off_t offset, int whence, struct thread *td) 2503 { 2504 struct ucred *cred; 2505 struct vnode *vp; 2506 struct vattr vattr; 2507 off_t foffset, size; 2508 int error, noneg; 2509 2510 cred = td->td_ucred; 2511 vp = fp->f_vnode; 2512 foffset = foffset_lock(fp, 0); 2513 noneg = (vp->v_type != VCHR); 2514 error = 0; 2515 switch (whence) { 2516 case L_INCR: 2517 if (noneg && 2518 (foffset < 0 || 2519 (offset > 0 && foffset > OFF_MAX - offset))) { 2520 error = EOVERFLOW; 2521 break; 2522 } 2523 offset += foffset; 2524 break; 2525 case L_XTND: 2526 vn_lock(vp, LK_SHARED | LK_RETRY); 2527 error = VOP_GETATTR(vp, &vattr, cred); 2528 VOP_UNLOCK(vp); 2529 if (error) 2530 break; 2531 2532 /* 2533 * If the file references a disk device, then fetch 2534 * the media size and use that to determine the ending 2535 * offset. 2536 */ 2537 if (vattr.va_size == 0 && vp->v_type == VCHR && 2538 fo_ioctl(fp, DIOCGMEDIASIZE, &size, cred, td) == 0) 2539 vattr.va_size = size; 2540 if (noneg && 2541 (vattr.va_size > OFF_MAX || 2542 (offset > 0 && vattr.va_size > OFF_MAX - offset))) { 2543 error = EOVERFLOW; 2544 break; 2545 } 2546 offset += vattr.va_size; 2547 break; 2548 case L_SET: 2549 break; 2550 case SEEK_DATA: 2551 error = fo_ioctl(fp, FIOSEEKDATA, &offset, cred, td); 2552 if (error == ENOTTY) 2553 error = EINVAL; 2554 break; 2555 case SEEK_HOLE: 2556 error = fo_ioctl(fp, FIOSEEKHOLE, &offset, cred, td); 2557 if (error == ENOTTY) 2558 error = EINVAL; 2559 break; 2560 default: 2561 error = EINVAL; 2562 } 2563 if (error == 0 && noneg && offset < 0) 2564 error = EINVAL; 2565 if (error != 0) 2566 goto drop; 2567 VFS_KNOTE_UNLOCKED(vp, 0); 2568 td->td_uretoff.tdu_off = offset; 2569 drop: 2570 foffset_unlock(fp, offset, error != 0 ? FOF_NOUPDATE : 0); 2571 return (error); 2572 } 2573 2574 int 2575 vn_utimes_perm(struct vnode *vp, struct vattr *vap, struct ucred *cred, 2576 struct thread *td) 2577 { 2578 int error; 2579 2580 /* 2581 * Grant permission if the caller is the owner of the file, or 2582 * the super-user, or has ACL_WRITE_ATTRIBUTES permission on 2583 * on the file. If the time pointer is null, then write 2584 * permission on the file is also sufficient. 2585 * 2586 * From NFSv4.1, draft 21, 6.2.1.3.1, Discussion of Mask Attributes: 2587 * A user having ACL_WRITE_DATA or ACL_WRITE_ATTRIBUTES 2588 * will be allowed to set the times [..] to the current 2589 * server time. 2590 */ 2591 error = VOP_ACCESSX(vp, VWRITE_ATTRIBUTES, cred, td); 2592 if (error != 0 && (vap->va_vaflags & VA_UTIMES_NULL) != 0) 2593 error = VOP_ACCESS(vp, VWRITE, cred, td); 2594 return (error); 2595 } 2596 2597 int 2598 vn_fill_kinfo(struct file *fp, struct kinfo_file *kif, struct filedesc *fdp) 2599 { 2600 struct vnode *vp; 2601 int error; 2602 2603 if (fp->f_type == DTYPE_FIFO) 2604 kif->kf_type = KF_TYPE_FIFO; 2605 else 2606 kif->kf_type = KF_TYPE_VNODE; 2607 vp = fp->f_vnode; 2608 vref(vp); 2609 FILEDESC_SUNLOCK(fdp); 2610 error = vn_fill_kinfo_vnode(vp, kif); 2611 vrele(vp); 2612 FILEDESC_SLOCK(fdp); 2613 return (error); 2614 } 2615 2616 static inline void 2617 vn_fill_junk(struct kinfo_file *kif) 2618 { 2619 size_t len, olen; 2620 2621 /* 2622 * Simulate vn_fullpath returning changing values for a given 2623 * vp during e.g. coredump. 2624 */ 2625 len = (arc4random() % (sizeof(kif->kf_path) - 2)) + 1; 2626 olen = strlen(kif->kf_path); 2627 if (len < olen) 2628 strcpy(&kif->kf_path[len - 1], "$"); 2629 else 2630 for (; olen < len; olen++) 2631 strcpy(&kif->kf_path[olen], "A"); 2632 } 2633 2634 int 2635 vn_fill_kinfo_vnode(struct vnode *vp, struct kinfo_file *kif) 2636 { 2637 struct vattr va; 2638 char *fullpath, *freepath; 2639 int error; 2640 2641 kif->kf_un.kf_file.kf_file_type = vntype_to_kinfo(vp->v_type); 2642 freepath = NULL; 2643 fullpath = "-"; 2644 error = vn_fullpath(vp, &fullpath, &freepath); 2645 if (error == 0) { 2646 strlcpy(kif->kf_path, fullpath, sizeof(kif->kf_path)); 2647 } 2648 if (freepath != NULL) 2649 free(freepath, M_TEMP); 2650 2651 KFAIL_POINT_CODE(DEBUG_FP, fill_kinfo_vnode__random_path, 2652 vn_fill_junk(kif); 2653 ); 2654 2655 /* 2656 * Retrieve vnode attributes. 2657 */ 2658 va.va_fsid = VNOVAL; 2659 va.va_rdev = NODEV; 2660 vn_lock(vp, LK_SHARED | LK_RETRY); 2661 error = VOP_GETATTR(vp, &va, curthread->td_ucred); 2662 VOP_UNLOCK(vp); 2663 if (error != 0) 2664 return (error); 2665 if (va.va_fsid != VNOVAL) 2666 kif->kf_un.kf_file.kf_file_fsid = va.va_fsid; 2667 else 2668 kif->kf_un.kf_file.kf_file_fsid = 2669 vp->v_mount->mnt_stat.f_fsid.val[0]; 2670 kif->kf_un.kf_file.kf_file_fsid_freebsd11 = 2671 kif->kf_un.kf_file.kf_file_fsid; /* truncate */ 2672 kif->kf_un.kf_file.kf_file_fileid = va.va_fileid; 2673 kif->kf_un.kf_file.kf_file_mode = MAKEIMODE(va.va_type, va.va_mode); 2674 kif->kf_un.kf_file.kf_file_size = va.va_size; 2675 kif->kf_un.kf_file.kf_file_rdev = va.va_rdev; 2676 kif->kf_un.kf_file.kf_file_rdev_freebsd11 = 2677 kif->kf_un.kf_file.kf_file_rdev; /* truncate */ 2678 return (0); 2679 } 2680 2681 int 2682 vn_mmap(struct file *fp, vm_map_t map, vm_offset_t *addr, vm_size_t size, 2683 vm_prot_t prot, vm_prot_t cap_maxprot, int flags, vm_ooffset_t foff, 2684 struct thread *td) 2685 { 2686 #ifdef HWPMC_HOOKS 2687 struct pmckern_map_in pkm; 2688 #endif 2689 struct mount *mp; 2690 struct vnode *vp; 2691 vm_object_t object; 2692 vm_prot_t maxprot; 2693 boolean_t writecounted; 2694 int error; 2695 2696 #if defined(COMPAT_FREEBSD7) || defined(COMPAT_FREEBSD6) || \ 2697 defined(COMPAT_FREEBSD5) || defined(COMPAT_FREEBSD4) 2698 /* 2699 * POSIX shared-memory objects are defined to have 2700 * kernel persistence, and are not defined to support 2701 * read(2)/write(2) -- or even open(2). Thus, we can 2702 * use MAP_ASYNC to trade on-disk coherence for speed. 2703 * The shm_open(3) library routine turns on the FPOSIXSHM 2704 * flag to request this behavior. 2705 */ 2706 if ((fp->f_flag & FPOSIXSHM) != 0) 2707 flags |= MAP_NOSYNC; 2708 #endif 2709 vp = fp->f_vnode; 2710 2711 /* 2712 * Ensure that file and memory protections are 2713 * compatible. Note that we only worry about 2714 * writability if mapping is shared; in this case, 2715 * current and max prot are dictated by the open file. 2716 * XXX use the vnode instead? Problem is: what 2717 * credentials do we use for determination? What if 2718 * proc does a setuid? 2719 */ 2720 mp = vp->v_mount; 2721 if (mp != NULL && (mp->mnt_flag & MNT_NOEXEC) != 0) { 2722 maxprot = VM_PROT_NONE; 2723 if ((prot & VM_PROT_EXECUTE) != 0) 2724 return (EACCES); 2725 } else 2726 maxprot = VM_PROT_EXECUTE; 2727 if ((fp->f_flag & FREAD) != 0) 2728 maxprot |= VM_PROT_READ; 2729 else if ((prot & VM_PROT_READ) != 0) 2730 return (EACCES); 2731 2732 /* 2733 * If we are sharing potential changes via MAP_SHARED and we 2734 * are trying to get write permission although we opened it 2735 * without asking for it, bail out. 2736 */ 2737 if ((flags & MAP_SHARED) != 0) { 2738 if ((fp->f_flag & FWRITE) != 0) 2739 maxprot |= VM_PROT_WRITE; 2740 else if ((prot & VM_PROT_WRITE) != 0) 2741 return (EACCES); 2742 } else { 2743 maxprot |= VM_PROT_WRITE; 2744 cap_maxprot |= VM_PROT_WRITE; 2745 } 2746 maxprot &= cap_maxprot; 2747 2748 /* 2749 * For regular files and shared memory, POSIX requires that 2750 * the value of foff be a legitimate offset within the data 2751 * object. In particular, negative offsets are invalid. 2752 * Blocking negative offsets and overflows here avoids 2753 * possible wraparound or user-level access into reserved 2754 * ranges of the data object later. In contrast, POSIX does 2755 * not dictate how offsets are used by device drivers, so in 2756 * the case of a device mapping a negative offset is passed 2757 * on. 2758 */ 2759 if ( 2760 #ifdef _LP64 2761 size > OFF_MAX || 2762 #endif 2763 foff > OFF_MAX - size) 2764 return (EINVAL); 2765 2766 writecounted = FALSE; 2767 error = vm_mmap_vnode(td, size, prot, &maxprot, &flags, vp, 2768 &foff, &object, &writecounted); 2769 if (error != 0) 2770 return (error); 2771 error = vm_mmap_object(map, addr, size, prot, maxprot, flags, object, 2772 foff, writecounted, td); 2773 if (error != 0) { 2774 /* 2775 * If this mapping was accounted for in the vnode's 2776 * writecount, then undo that now. 2777 */ 2778 if (writecounted) 2779 vm_pager_release_writecount(object, 0, size); 2780 vm_object_deallocate(object); 2781 } 2782 #ifdef HWPMC_HOOKS 2783 /* Inform hwpmc(4) if an executable is being mapped. */ 2784 if (PMC_HOOK_INSTALLED(PMC_FN_MMAP)) { 2785 if ((prot & VM_PROT_EXECUTE) != 0 && error == 0) { 2786 pkm.pm_file = vp; 2787 pkm.pm_address = (uintptr_t) *addr; 2788 PMC_CALL_HOOK_UNLOCKED(td, PMC_FN_MMAP, (void *) &pkm); 2789 } 2790 } 2791 #endif 2792 return (error); 2793 } 2794 2795 void 2796 vn_fsid(struct vnode *vp, struct vattr *va) 2797 { 2798 fsid_t *f; 2799 2800 f = &vp->v_mount->mnt_stat.f_fsid; 2801 va->va_fsid = (uint32_t)f->val[1]; 2802 va->va_fsid <<= sizeof(f->val[1]) * NBBY; 2803 va->va_fsid += (uint32_t)f->val[0]; 2804 } 2805 2806 int 2807 vn_fsync_buf(struct vnode *vp, int waitfor) 2808 { 2809 struct buf *bp, *nbp; 2810 struct bufobj *bo; 2811 struct mount *mp; 2812 int error, maxretry; 2813 2814 error = 0; 2815 maxretry = 10000; /* large, arbitrarily chosen */ 2816 mp = NULL; 2817 if (vp->v_type == VCHR) { 2818 VI_LOCK(vp); 2819 mp = vp->v_rdev->si_mountpt; 2820 VI_UNLOCK(vp); 2821 } 2822 bo = &vp->v_bufobj; 2823 BO_LOCK(bo); 2824 loop1: 2825 /* 2826 * MARK/SCAN initialization to avoid infinite loops. 2827 */ 2828 TAILQ_FOREACH(bp, &bo->bo_dirty.bv_hd, b_bobufs) { 2829 bp->b_vflags &= ~BV_SCANNED; 2830 bp->b_error = 0; 2831 } 2832 2833 /* 2834 * Flush all dirty buffers associated with a vnode. 2835 */ 2836 loop2: 2837 TAILQ_FOREACH_SAFE(bp, &bo->bo_dirty.bv_hd, b_bobufs, nbp) { 2838 if ((bp->b_vflags & BV_SCANNED) != 0) 2839 continue; 2840 bp->b_vflags |= BV_SCANNED; 2841 if (BUF_LOCK(bp, LK_EXCLUSIVE | LK_NOWAIT, NULL)) { 2842 if (waitfor != MNT_WAIT) 2843 continue; 2844 if (BUF_LOCK(bp, 2845 LK_EXCLUSIVE | LK_INTERLOCK | LK_SLEEPFAIL, 2846 BO_LOCKPTR(bo)) != 0) { 2847 BO_LOCK(bo); 2848 goto loop1; 2849 } 2850 BO_LOCK(bo); 2851 } 2852 BO_UNLOCK(bo); 2853 KASSERT(bp->b_bufobj == bo, 2854 ("bp %p wrong b_bufobj %p should be %p", 2855 bp, bp->b_bufobj, bo)); 2856 if ((bp->b_flags & B_DELWRI) == 0) 2857 panic("fsync: not dirty"); 2858 if ((vp->v_object != NULL) && (bp->b_flags & B_CLUSTEROK)) { 2859 vfs_bio_awrite(bp); 2860 } else { 2861 bremfree(bp); 2862 bawrite(bp); 2863 } 2864 if (maxretry < 1000) 2865 pause("dirty", hz < 1000 ? 1 : hz / 1000); 2866 BO_LOCK(bo); 2867 goto loop2; 2868 } 2869 2870 /* 2871 * If synchronous the caller expects us to completely resolve all 2872 * dirty buffers in the system. Wait for in-progress I/O to 2873 * complete (which could include background bitmap writes), then 2874 * retry if dirty blocks still exist. 2875 */ 2876 if (waitfor == MNT_WAIT) { 2877 bufobj_wwait(bo, 0, 0); 2878 if (bo->bo_dirty.bv_cnt > 0) { 2879 /* 2880 * If we are unable to write any of these buffers 2881 * then we fail now rather than trying endlessly 2882 * to write them out. 2883 */ 2884 TAILQ_FOREACH(bp, &bo->bo_dirty.bv_hd, b_bobufs) 2885 if ((error = bp->b_error) != 0) 2886 break; 2887 if ((mp != NULL && mp->mnt_secondary_writes > 0) || 2888 (error == 0 && --maxretry >= 0)) 2889 goto loop1; 2890 if (error == 0) 2891 error = EAGAIN; 2892 } 2893 } 2894 BO_UNLOCK(bo); 2895 if (error != 0) 2896 vn_printf(vp, "fsync: giving up on dirty (error = %d) ", error); 2897 2898 return (error); 2899 } 2900 2901 /* 2902 * Copies a byte range from invp to outvp. Calls VOP_COPY_FILE_RANGE() 2903 * or vn_generic_copy_file_range() after rangelocking the byte ranges, 2904 * to do the actual copy. 2905 * vn_generic_copy_file_range() is factored out, so it can be called 2906 * from a VOP_COPY_FILE_RANGE() call as well, but handles vnodes from 2907 * different file systems. 2908 */ 2909 int 2910 vn_copy_file_range(struct vnode *invp, off_t *inoffp, struct vnode *outvp, 2911 off_t *outoffp, size_t *lenp, unsigned int flags, struct ucred *incred, 2912 struct ucred *outcred, struct thread *fsize_td) 2913 { 2914 int error; 2915 size_t len; 2916 uint64_t uval; 2917 2918 len = *lenp; 2919 *lenp = 0; /* For error returns. */ 2920 error = 0; 2921 2922 /* Do some sanity checks on the arguments. */ 2923 if (invp->v_type == VDIR || outvp->v_type == VDIR) 2924 error = EISDIR; 2925 else if (*inoffp < 0 || *outoffp < 0 || 2926 invp->v_type != VREG || outvp->v_type != VREG) 2927 error = EINVAL; 2928 if (error != 0) 2929 goto out; 2930 2931 /* Ensure offset + len does not wrap around. */ 2932 uval = *inoffp; 2933 uval += len; 2934 if (uval > INT64_MAX) 2935 len = INT64_MAX - *inoffp; 2936 uval = *outoffp; 2937 uval += len; 2938 if (uval > INT64_MAX) 2939 len = INT64_MAX - *outoffp; 2940 if (len == 0) 2941 goto out; 2942 2943 /* 2944 * If the two vnode are for the same file system, call 2945 * VOP_COPY_FILE_RANGE(), otherwise call vn_generic_copy_file_range() 2946 * which can handle copies across multiple file systems. 2947 */ 2948 *lenp = len; 2949 if (invp->v_mount == outvp->v_mount) 2950 error = VOP_COPY_FILE_RANGE(invp, inoffp, outvp, outoffp, 2951 lenp, flags, incred, outcred, fsize_td); 2952 else 2953 error = vn_generic_copy_file_range(invp, inoffp, outvp, 2954 outoffp, lenp, flags, incred, outcred, fsize_td); 2955 out: 2956 return (error); 2957 } 2958 2959 /* 2960 * Test len bytes of data starting at dat for all bytes == 0. 2961 * Return true if all bytes are zero, false otherwise. 2962 * Expects dat to be well aligned. 2963 */ 2964 static bool 2965 mem_iszero(void *dat, int len) 2966 { 2967 int i; 2968 const u_int *p; 2969 const char *cp; 2970 2971 for (p = dat; len > 0; len -= sizeof(*p), p++) { 2972 if (len >= sizeof(*p)) { 2973 if (*p != 0) 2974 return (false); 2975 } else { 2976 cp = (const char *)p; 2977 for (i = 0; i < len; i++, cp++) 2978 if (*cp != '\0') 2979 return (false); 2980 } 2981 } 2982 return (true); 2983 } 2984 2985 /* 2986 * Look for a hole in the output file and, if found, adjust *outoffp 2987 * and *xferp to skip past the hole. 2988 * *xferp is the entire hole length to be written and xfer2 is how many bytes 2989 * to be written as 0's upon return. 2990 */ 2991 static off_t 2992 vn_skip_hole(struct vnode *outvp, off_t xfer2, off_t *outoffp, off_t *xferp, 2993 off_t *dataoffp, off_t *holeoffp, struct ucred *cred) 2994 { 2995 int error; 2996 off_t delta; 2997 2998 if (*holeoffp == 0 || *holeoffp <= *outoffp) { 2999 *dataoffp = *outoffp; 3000 error = VOP_IOCTL(outvp, FIOSEEKDATA, dataoffp, 0, cred, 3001 curthread); 3002 if (error == 0) { 3003 *holeoffp = *dataoffp; 3004 error = VOP_IOCTL(outvp, FIOSEEKHOLE, holeoffp, 0, cred, 3005 curthread); 3006 } 3007 if (error != 0 || *holeoffp == *dataoffp) { 3008 /* 3009 * Since outvp is unlocked, it may be possible for 3010 * another thread to do a truncate(), lseek(), write() 3011 * creating a hole at startoff between the above 3012 * VOP_IOCTL() calls, if the other thread does not do 3013 * rangelocking. 3014 * If that happens, *holeoffp == *dataoffp and finding 3015 * the hole has failed, so disable vn_skip_hole(). 3016 */ 3017 *holeoffp = -1; /* Disable use of vn_skip_hole(). */ 3018 return (xfer2); 3019 } 3020 KASSERT(*dataoffp >= *outoffp, 3021 ("vn_skip_hole: dataoff=%jd < outoff=%jd", 3022 (intmax_t)*dataoffp, (intmax_t)*outoffp)); 3023 KASSERT(*holeoffp > *dataoffp, 3024 ("vn_skip_hole: holeoff=%jd <= dataoff=%jd", 3025 (intmax_t)*holeoffp, (intmax_t)*dataoffp)); 3026 } 3027 3028 /* 3029 * If there is a hole before the data starts, advance *outoffp and 3030 * *xferp past the hole. 3031 */ 3032 if (*dataoffp > *outoffp) { 3033 delta = *dataoffp - *outoffp; 3034 if (delta >= *xferp) { 3035 /* Entire *xferp is a hole. */ 3036 *outoffp += *xferp; 3037 *xferp = 0; 3038 return (0); 3039 } 3040 *xferp -= delta; 3041 *outoffp += delta; 3042 xfer2 = MIN(xfer2, *xferp); 3043 } 3044 3045 /* 3046 * If a hole starts before the end of this xfer2, reduce this xfer2 so 3047 * that the write ends at the start of the hole. 3048 * *holeoffp should always be greater than *outoffp, but for the 3049 * non-INVARIANTS case, check this to make sure xfer2 remains a sane 3050 * value. 3051 */ 3052 if (*holeoffp > *outoffp && *holeoffp < *outoffp + xfer2) 3053 xfer2 = *holeoffp - *outoffp; 3054 return (xfer2); 3055 } 3056 3057 /* 3058 * Write an xfer sized chunk to outvp in blksize blocks from dat. 3059 * dat is a maximum of blksize in length and can be written repeatedly in 3060 * the chunk. 3061 * If growfile == true, just grow the file via vn_truncate_locked() instead 3062 * of doing actual writes. 3063 * If checkhole == true, a hole is being punched, so skip over any hole 3064 * already in the output file. 3065 */ 3066 static int 3067 vn_write_outvp(struct vnode *outvp, char *dat, off_t outoff, off_t xfer, 3068 u_long blksize, bool growfile, bool checkhole, struct ucred *cred) 3069 { 3070 struct mount *mp; 3071 off_t dataoff, holeoff, xfer2; 3072 int error; 3073 3074 /* 3075 * Loop around doing writes of blksize until write has been completed. 3076 * Lock/unlock on each loop iteration so that a bwillwrite() can be 3077 * done for each iteration, since the xfer argument can be very 3078 * large if there is a large hole to punch in the output file. 3079 */ 3080 error = 0; 3081 holeoff = 0; 3082 do { 3083 xfer2 = MIN(xfer, blksize); 3084 if (checkhole) { 3085 /* 3086 * Punching a hole. Skip writing if there is 3087 * already a hole in the output file. 3088 */ 3089 xfer2 = vn_skip_hole(outvp, xfer2, &outoff, &xfer, 3090 &dataoff, &holeoff, cred); 3091 if (xfer == 0) 3092 break; 3093 if (holeoff < 0) 3094 checkhole = false; 3095 KASSERT(xfer2 > 0, ("vn_write_outvp: xfer2=%jd", 3096 (intmax_t)xfer2)); 3097 } 3098 bwillwrite(); 3099 mp = NULL; 3100 error = vn_start_write(outvp, &mp, V_WAIT); 3101 if (error != 0) 3102 break; 3103 if (growfile) { 3104 error = vn_lock(outvp, LK_EXCLUSIVE); 3105 if (error == 0) { 3106 error = vn_truncate_locked(outvp, outoff + xfer, 3107 false, cred); 3108 VOP_UNLOCK(outvp); 3109 } 3110 } else { 3111 error = vn_lock(outvp, vn_lktype_write(mp, outvp)); 3112 if (error == 0) { 3113 error = vn_rdwr(UIO_WRITE, outvp, dat, xfer2, 3114 outoff, UIO_SYSSPACE, IO_NODELOCKED, 3115 curthread->td_ucred, cred, NULL, curthread); 3116 outoff += xfer2; 3117 xfer -= xfer2; 3118 VOP_UNLOCK(outvp); 3119 } 3120 } 3121 if (mp != NULL) 3122 vn_finished_write(mp); 3123 } while (!growfile && xfer > 0 && error == 0); 3124 return (error); 3125 } 3126 3127 /* 3128 * Copy a byte range of one file to another. This function can handle the 3129 * case where invp and outvp are on different file systems. 3130 * It can also be called by a VOP_COPY_FILE_RANGE() to do the work, if there 3131 * is no better file system specific way to do it. 3132 */ 3133 int 3134 vn_generic_copy_file_range(struct vnode *invp, off_t *inoffp, 3135 struct vnode *outvp, off_t *outoffp, size_t *lenp, unsigned int flags, 3136 struct ucred *incred, struct ucred *outcred, struct thread *fsize_td) 3137 { 3138 struct vattr va, inva; 3139 struct mount *mp; 3140 struct uio io; 3141 off_t startoff, endoff, xfer, xfer2; 3142 u_long blksize; 3143 int error, interrupted; 3144 bool cantseek, readzeros, eof, lastblock, holetoeof; 3145 ssize_t aresid; 3146 size_t copylen, len, rem, savlen; 3147 char *dat; 3148 long holein, holeout; 3149 3150 holein = holeout = 0; 3151 savlen = len = *lenp; 3152 error = 0; 3153 interrupted = 0; 3154 dat = NULL; 3155 3156 error = vn_lock(invp, LK_SHARED); 3157 if (error != 0) 3158 goto out; 3159 if (VOP_PATHCONF(invp, _PC_MIN_HOLE_SIZE, &holein) != 0) 3160 holein = 0; 3161 if (holein > 0) 3162 error = VOP_GETATTR(invp, &inva, incred); 3163 VOP_UNLOCK(invp); 3164 if (error != 0) 3165 goto out; 3166 3167 mp = NULL; 3168 error = vn_start_write(outvp, &mp, V_WAIT); 3169 if (error == 0) 3170 error = vn_lock(outvp, LK_EXCLUSIVE); 3171 if (error == 0) { 3172 /* 3173 * If fsize_td != NULL, do a vn_rlimit_fsize() call, 3174 * now that outvp is locked. 3175 */ 3176 if (fsize_td != NULL) { 3177 io.uio_offset = *outoffp; 3178 io.uio_resid = len; 3179 error = vn_rlimit_fsize(outvp, &io, fsize_td); 3180 if (error != 0) 3181 error = EFBIG; 3182 } 3183 if (VOP_PATHCONF(outvp, _PC_MIN_HOLE_SIZE, &holeout) != 0) 3184 holeout = 0; 3185 /* 3186 * Holes that are past EOF do not need to be written as a block 3187 * of zero bytes. So, truncate the output file as far as 3188 * possible and then use va.va_size to decide if writing 0 3189 * bytes is necessary in the loop below. 3190 */ 3191 if (error == 0) 3192 error = VOP_GETATTR(outvp, &va, outcred); 3193 if (error == 0 && va.va_size > *outoffp && va.va_size <= 3194 *outoffp + len) { 3195 #ifdef MAC 3196 error = mac_vnode_check_write(curthread->td_ucred, 3197 outcred, outvp); 3198 if (error == 0) 3199 #endif 3200 error = vn_truncate_locked(outvp, *outoffp, 3201 false, outcred); 3202 if (error == 0) 3203 va.va_size = *outoffp; 3204 } 3205 VOP_UNLOCK(outvp); 3206 } 3207 if (mp != NULL) 3208 vn_finished_write(mp); 3209 if (error != 0) 3210 goto out; 3211 3212 /* 3213 * Set the blksize to the larger of the hole sizes for invp and outvp. 3214 * If hole sizes aren't available, set the blksize to the larger 3215 * f_iosize of invp and outvp. 3216 * This code expects the hole sizes and f_iosizes to be powers of 2. 3217 * This value is clipped at 4Kbytes and 1Mbyte. 3218 */ 3219 blksize = MAX(holein, holeout); 3220 3221 /* Clip len to end at an exact multiple of hole size. */ 3222 if (blksize > 1) { 3223 rem = *inoffp % blksize; 3224 if (rem > 0) 3225 rem = blksize - rem; 3226 if (len > rem && len - rem > blksize) 3227 len = savlen = rounddown(len - rem, blksize) + rem; 3228 } 3229 3230 if (blksize <= 1) 3231 blksize = MAX(invp->v_mount->mnt_stat.f_iosize, 3232 outvp->v_mount->mnt_stat.f_iosize); 3233 if (blksize < 4096) 3234 blksize = 4096; 3235 else if (blksize > 1024 * 1024) 3236 blksize = 1024 * 1024; 3237 dat = malloc(blksize, M_TEMP, M_WAITOK); 3238 3239 /* 3240 * If VOP_IOCTL(FIOSEEKHOLE) works for invp, use it and FIOSEEKDATA 3241 * to find holes. Otherwise, just scan the read block for all 0s 3242 * in the inner loop where the data copying is done. 3243 * Note that some file systems such as NFSv3, NFSv4.0 and NFSv4.1 may 3244 * support holes on the server, but do not support FIOSEEKHOLE. 3245 */ 3246 holetoeof = eof = false; 3247 while (len > 0 && error == 0 && !eof && interrupted == 0) { 3248 endoff = 0; /* To shut up compilers. */ 3249 cantseek = true; 3250 startoff = *inoffp; 3251 copylen = len; 3252 3253 /* 3254 * Find the next data area. If there is just a hole to EOF, 3255 * FIOSEEKDATA should fail with ENXIO. 3256 * (I do not know if any file system will report a hole to 3257 * EOF via FIOSEEKHOLE, but I am pretty sure FIOSEEKDATA 3258 * will fail for those file systems.) 3259 * 3260 * For input files that don't support FIOSEEKDATA/FIOSEEKHOLE, 3261 * the code just falls through to the inner copy loop. 3262 */ 3263 error = EINVAL; 3264 if (holein > 0) { 3265 error = VOP_IOCTL(invp, FIOSEEKDATA, &startoff, 0, 3266 incred, curthread); 3267 if (error == ENXIO) { 3268 startoff = endoff = inva.va_size; 3269 eof = holetoeof = true; 3270 error = 0; 3271 } 3272 } 3273 if (error == 0 && !holetoeof) { 3274 endoff = startoff; 3275 error = VOP_IOCTL(invp, FIOSEEKHOLE, &endoff, 0, 3276 incred, curthread); 3277 /* 3278 * Since invp is unlocked, it may be possible for 3279 * another thread to do a truncate(), lseek(), write() 3280 * creating a hole at startoff between the above 3281 * VOP_IOCTL() calls, if the other thread does not do 3282 * rangelocking. 3283 * If that happens, startoff == endoff and finding 3284 * the hole has failed, so set an error. 3285 */ 3286 if (error == 0 && startoff == endoff) 3287 error = EINVAL; /* Any error. Reset to 0. */ 3288 } 3289 if (error == 0) { 3290 if (startoff > *inoffp) { 3291 /* Found hole before data block. */ 3292 xfer = MIN(startoff - *inoffp, len); 3293 if (*outoffp < va.va_size) { 3294 /* Must write 0s to punch hole. */ 3295 xfer2 = MIN(va.va_size - *outoffp, 3296 xfer); 3297 memset(dat, 0, MIN(xfer2, blksize)); 3298 error = vn_write_outvp(outvp, dat, 3299 *outoffp, xfer2, blksize, false, 3300 holeout > 0, outcred); 3301 } 3302 3303 if (error == 0 && *outoffp + xfer > 3304 va.va_size && (xfer == len || holetoeof)) { 3305 /* Grow output file (hole at end). */ 3306 error = vn_write_outvp(outvp, dat, 3307 *outoffp, xfer, blksize, true, 3308 false, outcred); 3309 } 3310 if (error == 0) { 3311 *inoffp += xfer; 3312 *outoffp += xfer; 3313 len -= xfer; 3314 if (len < savlen) 3315 interrupted = sig_intr(); 3316 } 3317 } 3318 copylen = MIN(len, endoff - startoff); 3319 cantseek = false; 3320 } else { 3321 cantseek = true; 3322 startoff = *inoffp; 3323 copylen = len; 3324 error = 0; 3325 } 3326 3327 xfer = blksize; 3328 if (cantseek) { 3329 /* 3330 * Set first xfer to end at a block boundary, so that 3331 * holes are more likely detected in the loop below via 3332 * the for all bytes 0 method. 3333 */ 3334 xfer -= (*inoffp % blksize); 3335 } 3336 /* Loop copying the data block. */ 3337 while (copylen > 0 && error == 0 && !eof && interrupted == 0) { 3338 if (copylen < xfer) 3339 xfer = copylen; 3340 error = vn_lock(invp, LK_SHARED); 3341 if (error != 0) 3342 goto out; 3343 error = vn_rdwr(UIO_READ, invp, dat, xfer, 3344 startoff, UIO_SYSSPACE, IO_NODELOCKED, 3345 curthread->td_ucred, incred, &aresid, 3346 curthread); 3347 VOP_UNLOCK(invp); 3348 lastblock = false; 3349 if (error == 0 && aresid > 0) { 3350 /* Stop the copy at EOF on the input file. */ 3351 xfer -= aresid; 3352 eof = true; 3353 lastblock = true; 3354 } 3355 if (error == 0) { 3356 /* 3357 * Skip the write for holes past the initial EOF 3358 * of the output file, unless this is the last 3359 * write of the output file at EOF. 3360 */ 3361 readzeros = cantseek ? mem_iszero(dat, xfer) : 3362 false; 3363 if (xfer == len) 3364 lastblock = true; 3365 if (!cantseek || *outoffp < va.va_size || 3366 lastblock || !readzeros) 3367 error = vn_write_outvp(outvp, dat, 3368 *outoffp, xfer, blksize, 3369 readzeros && lastblock && 3370 *outoffp >= va.va_size, false, 3371 outcred); 3372 if (error == 0) { 3373 *inoffp += xfer; 3374 startoff += xfer; 3375 *outoffp += xfer; 3376 copylen -= xfer; 3377 len -= xfer; 3378 if (len < savlen) 3379 interrupted = sig_intr(); 3380 } 3381 } 3382 xfer = blksize; 3383 } 3384 } 3385 out: 3386 *lenp = savlen - len; 3387 free(dat, M_TEMP); 3388 return (error); 3389 } 3390 3391 static int 3392 vn_fallocate(struct file *fp, off_t offset, off_t len, struct thread *td) 3393 { 3394 struct mount *mp; 3395 struct vnode *vp; 3396 off_t olen, ooffset; 3397 int error; 3398 #ifdef AUDIT 3399 int audited_vnode1 = 0; 3400 #endif 3401 3402 vp = fp->f_vnode; 3403 if (vp->v_type != VREG) 3404 return (ENODEV); 3405 3406 /* Allocating blocks may take a long time, so iterate. */ 3407 for (;;) { 3408 olen = len; 3409 ooffset = offset; 3410 3411 bwillwrite(); 3412 mp = NULL; 3413 error = vn_start_write(vp, &mp, V_WAIT | PCATCH); 3414 if (error != 0) 3415 break; 3416 error = vn_lock(vp, LK_EXCLUSIVE); 3417 if (error != 0) { 3418 vn_finished_write(mp); 3419 break; 3420 } 3421 #ifdef AUDIT 3422 if (!audited_vnode1) { 3423 AUDIT_ARG_VNODE1(vp); 3424 audited_vnode1 = 1; 3425 } 3426 #endif 3427 #ifdef MAC 3428 error = mac_vnode_check_write(td->td_ucred, fp->f_cred, vp); 3429 if (error == 0) 3430 #endif 3431 error = VOP_ALLOCATE(vp, &offset, &len); 3432 VOP_UNLOCK(vp); 3433 vn_finished_write(mp); 3434 3435 if (olen + ooffset != offset + len) { 3436 panic("offset + len changed from %jx/%jx to %jx/%jx", 3437 ooffset, olen, offset, len); 3438 } 3439 if (error != 0 || len == 0) 3440 break; 3441 KASSERT(olen > len, ("Iteration did not make progress?")); 3442 maybe_yield(); 3443 } 3444 3445 return (error); 3446 } 3447 3448 static int 3449 vn_deallocate_impl(struct vnode *vp, off_t *offset, off_t *length, int flags, 3450 int ioflg, struct ucred *active_cred, struct ucred *file_cred) 3451 { 3452 struct mount *mp; 3453 void *rl_cookie; 3454 off_t off, len; 3455 int error; 3456 #ifdef AUDIT 3457 bool audited_vnode1 = false; 3458 #endif 3459 3460 rl_cookie = NULL; 3461 error = 0; 3462 mp = NULL; 3463 off = *offset; 3464 len = *length; 3465 3466 if ((ioflg & (IO_NODELOCKED|IO_RANGELOCKED)) == 0) 3467 rl_cookie = vn_rangelock_wlock(vp, off, off + len); 3468 while (len > 0 && error == 0) { 3469 /* 3470 * Try to deallocate the longest range in one pass. 3471 * In case a pass takes too long to be executed, it returns 3472 * partial result. The residue will be proceeded in the next 3473 * pass. 3474 */ 3475 3476 if ((ioflg & IO_NODELOCKED) == 0) { 3477 bwillwrite(); 3478 if ((error = vn_start_write(vp, &mp, 3479 V_WAIT | PCATCH)) != 0) 3480 goto out; 3481 vn_lock(vp, vn_lktype_write(mp, vp) | LK_RETRY); 3482 } 3483 #ifdef AUDIT 3484 if (!audited_vnode1) { 3485 AUDIT_ARG_VNODE1(vp); 3486 audited_vnode1 = true; 3487 } 3488 #endif 3489 3490 #ifdef MAC 3491 if ((ioflg & IO_NOMACCHECK) == 0) 3492 error = mac_vnode_check_write(active_cred, file_cred, 3493 vp); 3494 #endif 3495 if (error == 0) 3496 error = VOP_DEALLOCATE(vp, &off, &len, flags, 3497 active_cred); 3498 3499 if ((ioflg & IO_NODELOCKED) == 0) { 3500 VOP_UNLOCK(vp); 3501 if (mp != NULL) { 3502 vn_finished_write(mp); 3503 mp = NULL; 3504 } 3505 } 3506 } 3507 out: 3508 if (rl_cookie != NULL) 3509 vn_rangelock_unlock(vp, rl_cookie); 3510 *offset = off; 3511 *length = len; 3512 return (error); 3513 } 3514 3515 int 3516 vn_deallocate(struct vnode *vp, off_t *offset, off_t *length, int flags, 3517 int ioflg, struct ucred *active_cred, struct ucred *file_cred) 3518 { 3519 if (*offset < 0 || *length <= 0 || *length > OFF_MAX - *offset || 3520 flags != 0) 3521 return (EINVAL); 3522 if (vp->v_type != VREG) 3523 return (ENODEV); 3524 3525 return (vn_deallocate_impl(vp, offset, length, flags, ioflg, 3526 active_cred, file_cred)); 3527 } 3528 3529 static int 3530 vn_fspacectl(struct file *fp, int cmd, off_t *offset, off_t *length, int flags, 3531 struct ucred *active_cred, struct thread *td) 3532 { 3533 int error; 3534 struct vnode *vp; 3535 3536 vp = fp->f_vnode; 3537 3538 if (cmd != SPACECTL_DEALLOC || *offset < 0 || *length <= 0 || 3539 *length > OFF_MAX - *offset || flags != 0) 3540 return (EINVAL); 3541 if (vp->v_type != VREG) 3542 return (ENODEV); 3543 3544 switch (cmd) { 3545 case SPACECTL_DEALLOC: 3546 error = vn_deallocate_impl(vp, offset, length, flags, 0, 3547 active_cred, fp->f_cred); 3548 break; 3549 default: 3550 panic("vn_fspacectl: unknown cmd %d", cmd); 3551 } 3552 3553 return (error); 3554 } 3555 3556 static u_long vn_lock_pair_pause_cnt; 3557 SYSCTL_ULONG(_debug, OID_AUTO, vn_lock_pair_pause, CTLFLAG_RD, 3558 &vn_lock_pair_pause_cnt, 0, 3559 "Count of vn_lock_pair deadlocks"); 3560 3561 u_int vn_lock_pair_pause_max; 3562 SYSCTL_UINT(_debug, OID_AUTO, vn_lock_pair_pause_max, CTLFLAG_RW, 3563 &vn_lock_pair_pause_max, 0, 3564 "Max ticks for vn_lock_pair deadlock avoidance sleep"); 3565 3566 static void 3567 vn_lock_pair_pause(const char *wmesg) 3568 { 3569 atomic_add_long(&vn_lock_pair_pause_cnt, 1); 3570 pause(wmesg, prng32_bounded(vn_lock_pair_pause_max)); 3571 } 3572 3573 /* 3574 * Lock pair of vnodes vp1, vp2, avoiding lock order reversal. 3575 * vp1_locked indicates whether vp1 is exclusively locked; if not, vp1 3576 * must be unlocked. Same for vp2 and vp2_locked. One of the vnodes 3577 * can be NULL. 3578 * 3579 * The function returns with both vnodes exclusively locked, and 3580 * guarantees that it does not create lock order reversal with other 3581 * threads during its execution. Both vnodes could be unlocked 3582 * temporary (and reclaimed). 3583 */ 3584 void 3585 vn_lock_pair(struct vnode *vp1, bool vp1_locked, struct vnode *vp2, 3586 bool vp2_locked) 3587 { 3588 int error; 3589 3590 if (vp1 == NULL && vp2 == NULL) 3591 return; 3592 if (vp1 != NULL) { 3593 if (vp1_locked) 3594 ASSERT_VOP_ELOCKED(vp1, "vp1"); 3595 else 3596 ASSERT_VOP_UNLOCKED(vp1, "vp1"); 3597 } else { 3598 vp1_locked = true; 3599 } 3600 if (vp2 != NULL) { 3601 if (vp2_locked) 3602 ASSERT_VOP_ELOCKED(vp2, "vp2"); 3603 else 3604 ASSERT_VOP_UNLOCKED(vp2, "vp2"); 3605 } else { 3606 vp2_locked = true; 3607 } 3608 if (!vp1_locked && !vp2_locked) { 3609 vn_lock(vp1, LK_EXCLUSIVE | LK_RETRY); 3610 vp1_locked = true; 3611 } 3612 3613 for (;;) { 3614 if (vp1_locked && vp2_locked) 3615 break; 3616 if (vp1_locked && vp2 != NULL) { 3617 if (vp1 != NULL) { 3618 error = VOP_LOCK1(vp2, LK_EXCLUSIVE | LK_NOWAIT, 3619 __FILE__, __LINE__); 3620 if (error == 0) 3621 break; 3622 VOP_UNLOCK(vp1); 3623 vp1_locked = false; 3624 vn_lock_pair_pause("vlp1"); 3625 } 3626 vn_lock(vp2, LK_EXCLUSIVE | LK_RETRY); 3627 vp2_locked = true; 3628 } 3629 if (vp2_locked && vp1 != NULL) { 3630 if (vp2 != NULL) { 3631 error = VOP_LOCK1(vp1, LK_EXCLUSIVE | LK_NOWAIT, 3632 __FILE__, __LINE__); 3633 if (error == 0) 3634 break; 3635 VOP_UNLOCK(vp2); 3636 vp2_locked = false; 3637 vn_lock_pair_pause("vlp2"); 3638 } 3639 vn_lock(vp1, LK_EXCLUSIVE | LK_RETRY); 3640 vp1_locked = true; 3641 } 3642 } 3643 if (vp1 != NULL) 3644 ASSERT_VOP_ELOCKED(vp1, "vp1 ret"); 3645 if (vp2 != NULL) 3646 ASSERT_VOP_ELOCKED(vp2, "vp2 ret"); 3647 } 3648 3649 int 3650 vn_lktype_write(struct mount *mp, struct vnode *vp) 3651 { 3652 if (MNT_SHARED_WRITES(mp) || 3653 (mp == NULL && MNT_SHARED_WRITES(vp->v_mount))) 3654 return (LK_SHARED); 3655 return (LK_EXCLUSIVE); 3656 } 3657