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