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