1 /*- 2 * SPDX-License-Identifier: BSD-3-Clause 3 * 4 * Copyright (c) 1982, 1986, 1989, 1993 5 * The Regents of the University of California. All rights reserved. 6 * (c) UNIX System Laboratories, Inc. 7 * All or some portions of this file are derived from material licensed 8 * to the University of California by American Telephone and Telegraph 9 * Co. or Unix System Laboratories, Inc. and are reproduced herein with 10 * the permission of UNIX System Laboratories, Inc. 11 * 12 * Copyright (c) 2012 Konstantin Belousov <kib@FreeBSD.org> 13 * Copyright (c) 2013, 2014 The FreeBSD Foundation 14 * 15 * Portions of this software were developed by Konstantin Belousov 16 * under sponsorship from the FreeBSD Foundation. 17 * 18 * Redistribution and use in source and binary forms, with or without 19 * modification, are permitted provided that the following conditions 20 * are met: 21 * 1. Redistributions of source code must retain the above copyright 22 * notice, this list of conditions and the following disclaimer. 23 * 2. Redistributions in binary form must reproduce the above copyright 24 * notice, this list of conditions and the following disclaimer in the 25 * documentation and/or other materials provided with the distribution. 26 * 3. Neither the name of the University nor the names of its contributors 27 * may be used to endorse or promote products derived from this software 28 * without specific prior written permission. 29 * 30 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 31 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 32 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 33 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 34 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 35 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 36 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 37 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 38 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 39 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 40 * SUCH DAMAGE. 41 * 42 * @(#)vfs_vnops.c 8.2 (Berkeley) 1/21/94 43 */ 44 45 #include <sys/cdefs.h> 46 __FBSDID("$FreeBSD$"); 47 48 #include "opt_hwpmc_hooks.h" 49 50 #include <sys/param.h> 51 #include <sys/systm.h> 52 #include <sys/disk.h> 53 #include <sys/fail.h> 54 #include <sys/fcntl.h> 55 #include <sys/file.h> 56 #include <sys/kdb.h> 57 #include <sys/ktr.h> 58 #include <sys/stat.h> 59 #include <sys/priv.h> 60 #include <sys/proc.h> 61 #include <sys/limits.h> 62 #include <sys/lock.h> 63 #include <sys/mman.h> 64 #include <sys/mount.h> 65 #include <sys/mutex.h> 66 #include <sys/namei.h> 67 #include <sys/vnode.h> 68 #include <sys/bio.h> 69 #include <sys/buf.h> 70 #include <sys/filio.h> 71 #include <sys/resourcevar.h> 72 #include <sys/rwlock.h> 73 #include <sys/prng.h> 74 #include <sys/sx.h> 75 #include <sys/sleepqueue.h> 76 #include <sys/sysctl.h> 77 #include <sys/ttycom.h> 78 #include <sys/conf.h> 79 #include <sys/syslog.h> 80 #include <sys/unistd.h> 81 #include <sys/user.h> 82 83 #include <security/audit/audit.h> 84 #include <security/mac/mac_framework.h> 85 86 #include <vm/vm.h> 87 #include <vm/vm_extern.h> 88 #include <vm/pmap.h> 89 #include <vm/vm_map.h> 90 #include <vm/vm_object.h> 91 #include <vm/vm_page.h> 92 #include <vm/vm_pager.h> 93 94 #ifdef HWPMC_HOOKS 95 #include <sys/pmckern.h> 96 #endif 97 98 static fo_rdwr_t vn_read; 99 static fo_rdwr_t vn_write; 100 static fo_rdwr_t vn_io_fault; 101 static fo_truncate_t vn_truncate; 102 static fo_ioctl_t vn_ioctl; 103 static fo_poll_t vn_poll; 104 static fo_kqfilter_t vn_kqfilter; 105 static fo_close_t vn_closefile; 106 static fo_mmap_t vn_mmap; 107 static fo_fallocate_t vn_fallocate; 108 109 struct fileops vnops = { 110 .fo_read = vn_io_fault, 111 .fo_write = vn_io_fault, 112 .fo_truncate = vn_truncate, 113 .fo_ioctl = vn_ioctl, 114 .fo_poll = vn_poll, 115 .fo_kqfilter = vn_kqfilter, 116 .fo_stat = vn_statfile, 117 .fo_close = vn_closefile, 118 .fo_chmod = vn_chmod, 119 .fo_chown = vn_chown, 120 .fo_sendfile = vn_sendfile, 121 .fo_seek = vn_seek, 122 .fo_fill_kinfo = vn_fill_kinfo, 123 .fo_mmap = vn_mmap, 124 .fo_fallocate = vn_fallocate, 125 .fo_flags = DFLAG_PASSABLE | DFLAG_SEEKABLE 126 }; 127 128 const u_int io_hold_cnt = 16; 129 static int vn_io_fault_enable = 1; 130 SYSCTL_INT(_debug, OID_AUTO, vn_io_fault_enable, CTLFLAG_RWTUN, 131 &vn_io_fault_enable, 0, "Enable vn_io_fault lock avoidance"); 132 static int vn_io_fault_prefault = 0; 133 SYSCTL_INT(_debug, OID_AUTO, vn_io_fault_prefault, CTLFLAG_RWTUN, 134 &vn_io_fault_prefault, 0, "Enable vn_io_fault prefaulting"); 135 static int vn_io_pgcache_read_enable = 1; 136 SYSCTL_INT(_debug, OID_AUTO, vn_io_pgcache_read_enable, CTLFLAG_RWTUN, 137 &vn_io_pgcache_read_enable, 0, 138 "Enable copying from page cache for reads, avoiding fs"); 139 static u_long vn_io_faults_cnt; 140 SYSCTL_ULONG(_debug, OID_AUTO, vn_io_faults, CTLFLAG_RD, 141 &vn_io_faults_cnt, 0, "Count of vn_io_fault lock avoidance triggers"); 142 143 static int vfs_allow_read_dir = 0; 144 SYSCTL_INT(_security_bsd, OID_AUTO, allow_read_dir, CTLFLAG_RW, 145 &vfs_allow_read_dir, 0, 146 "Enable read(2) of directory by root for filesystems that support it"); 147 148 /* 149 * Returns true if vn_io_fault mode of handling the i/o request should 150 * be used. 151 */ 152 static bool 153 do_vn_io_fault(struct vnode *vp, struct uio *uio) 154 { 155 struct mount *mp; 156 157 return (uio->uio_segflg == UIO_USERSPACE && vp->v_type == VREG && 158 (mp = vp->v_mount) != NULL && 159 (mp->mnt_kern_flag & MNTK_NO_IOPF) != 0 && vn_io_fault_enable); 160 } 161 162 /* 163 * Structure used to pass arguments to vn_io_fault1(), to do either 164 * file- or vnode-based I/O calls. 165 */ 166 struct vn_io_fault_args { 167 enum { 168 VN_IO_FAULT_FOP, 169 VN_IO_FAULT_VOP 170 } kind; 171 struct ucred *cred; 172 int flags; 173 union { 174 struct fop_args_tag { 175 struct file *fp; 176 fo_rdwr_t *doio; 177 } fop_args; 178 struct vop_args_tag { 179 struct vnode *vp; 180 } vop_args; 181 } args; 182 }; 183 184 static int vn_io_fault1(struct vnode *vp, struct uio *uio, 185 struct vn_io_fault_args *args, struct thread *td); 186 187 int 188 vn_open(struct nameidata *ndp, int *flagp, int cmode, struct file *fp) 189 { 190 struct thread *td = ndp->ni_cnd.cn_thread; 191 192 return (vn_open_cred(ndp, flagp, cmode, 0, td->td_ucred, fp)); 193 } 194 195 static uint64_t 196 open2nameif(int fmode, u_int vn_open_flags) 197 { 198 uint64_t res; 199 200 res = ISOPEN | LOCKLEAF; 201 if ((fmode & O_RESOLVE_BENEATH) != 0) 202 res |= RBENEATH; 203 if ((fmode & O_EMPTY_PATH) != 0) 204 res |= EMPTYPATH; 205 if ((vn_open_flags & VN_OPEN_NOAUDIT) == 0) 206 res |= AUDITVNODE1; 207 if ((vn_open_flags & VN_OPEN_NOCAPCHECK) != 0) 208 res |= NOCAPCHECK; 209 return (res); 210 } 211 212 /* 213 * Common code for vnode open operations via a name lookup. 214 * Lookup the vnode and invoke VOP_CREATE if needed. 215 * Check permissions, and call the VOP_OPEN or VOP_CREATE routine. 216 * 217 * Note that this does NOT free nameidata for the successful case, 218 * due to the NDINIT being done elsewhere. 219 */ 220 int 221 vn_open_cred(struct nameidata *ndp, int *flagp, int cmode, u_int vn_open_flags, 222 struct ucred *cred, struct file *fp) 223 { 224 struct vnode *vp; 225 struct mount *mp; 226 struct thread *td = ndp->ni_cnd.cn_thread; 227 struct vattr vat; 228 struct vattr *vap = &vat; 229 int fmode, error; 230 bool first_open; 231 232 restart: 233 first_open = false; 234 fmode = *flagp; 235 if ((fmode & (O_CREAT | O_EXCL | O_DIRECTORY)) == (O_CREAT | 236 O_EXCL | O_DIRECTORY) || 237 (fmode & (O_CREAT | O_EMPTY_PATH)) == (O_CREAT | O_EMPTY_PATH)) 238 return (EINVAL); 239 else if ((fmode & (O_CREAT | O_DIRECTORY)) == O_CREAT) { 240 ndp->ni_cnd.cn_nameiop = CREATE; 241 ndp->ni_cnd.cn_flags = open2nameif(fmode, vn_open_flags); 242 /* 243 * Set NOCACHE to avoid flushing the cache when 244 * rolling in many files at once. 245 * 246 * Set NC_KEEPPOSENTRY to keep positive entries if they already 247 * exist despite NOCACHE. 248 */ 249 ndp->ni_cnd.cn_flags |= LOCKPARENT | NOCACHE | NC_KEEPPOSENTRY; 250 if ((fmode & O_EXCL) == 0 && (fmode & O_NOFOLLOW) == 0) 251 ndp->ni_cnd.cn_flags |= FOLLOW; 252 if ((vn_open_flags & VN_OPEN_INVFS) == 0) 253 bwillwrite(); 254 if ((error = namei(ndp)) != 0) 255 return (error); 256 if (ndp->ni_vp == NULL) { 257 VATTR_NULL(vap); 258 vap->va_type = VREG; 259 vap->va_mode = cmode; 260 if (fmode & O_EXCL) 261 vap->va_vaflags |= VA_EXCLUSIVE; 262 if (vn_start_write(ndp->ni_dvp, &mp, V_NOWAIT) != 0) { 263 NDFREE(ndp, NDF_ONLY_PNBUF); 264 vput(ndp->ni_dvp); 265 if ((error = vn_start_write(NULL, &mp, 266 V_XSLEEP | PCATCH)) != 0) 267 return (error); 268 NDREINIT(ndp); 269 goto restart; 270 } 271 if ((vn_open_flags & VN_OPEN_NAMECACHE) != 0) 272 ndp->ni_cnd.cn_flags |= MAKEENTRY; 273 #ifdef MAC 274 error = mac_vnode_check_create(cred, ndp->ni_dvp, 275 &ndp->ni_cnd, vap); 276 if (error == 0) 277 #endif 278 error = VOP_CREATE(ndp->ni_dvp, &ndp->ni_vp, 279 &ndp->ni_cnd, vap); 280 vp = ndp->ni_vp; 281 if (error == 0 && (fmode & O_EXCL) != 0 && 282 (fmode & (O_EXLOCK | O_SHLOCK)) != 0) { 283 VI_LOCK(vp); 284 vp->v_iflag |= VI_FOPENING; 285 VI_UNLOCK(vp); 286 first_open = true; 287 } 288 VOP_VPUT_PAIR(ndp->ni_dvp, error == 0 ? &vp : NULL, 289 false); 290 vn_finished_write(mp); 291 if (error) { 292 NDFREE(ndp, NDF_ONLY_PNBUF); 293 if (error == ERELOOKUP) { 294 NDREINIT(ndp); 295 goto restart; 296 } 297 return (error); 298 } 299 fmode &= ~O_TRUNC; 300 } else { 301 if (ndp->ni_dvp == ndp->ni_vp) 302 vrele(ndp->ni_dvp); 303 else 304 vput(ndp->ni_dvp); 305 ndp->ni_dvp = NULL; 306 vp = ndp->ni_vp; 307 if (fmode & O_EXCL) { 308 error = EEXIST; 309 goto bad; 310 } 311 if (vp->v_type == VDIR) { 312 error = EISDIR; 313 goto bad; 314 } 315 fmode &= ~O_CREAT; 316 } 317 } else { 318 ndp->ni_cnd.cn_nameiop = LOOKUP; 319 ndp->ni_cnd.cn_flags = open2nameif(fmode, vn_open_flags); 320 ndp->ni_cnd.cn_flags |= (fmode & O_NOFOLLOW) != 0 ? NOFOLLOW : 321 FOLLOW; 322 if ((fmode & FWRITE) == 0) 323 ndp->ni_cnd.cn_flags |= LOCKSHARED; 324 if ((error = namei(ndp)) != 0) 325 return (error); 326 vp = ndp->ni_vp; 327 } 328 error = vn_open_vnode(vp, fmode, cred, td, fp); 329 if (first_open) { 330 VI_LOCK(vp); 331 vp->v_iflag &= ~VI_FOPENING; 332 wakeup(vp); 333 VI_UNLOCK(vp); 334 } 335 if (error) 336 goto bad; 337 *flagp = fmode; 338 return (0); 339 bad: 340 NDFREE(ndp, NDF_ONLY_PNBUF); 341 vput(vp); 342 *flagp = fmode; 343 ndp->ni_vp = NULL; 344 return (error); 345 } 346 347 static int 348 vn_open_vnode_advlock(struct vnode *vp, int fmode, struct file *fp) 349 { 350 struct flock lf; 351 int error, lock_flags, type; 352 353 ASSERT_VOP_LOCKED(vp, "vn_open_vnode_advlock"); 354 if ((fmode & (O_EXLOCK | O_SHLOCK)) == 0) 355 return (0); 356 KASSERT(fp != NULL, ("open with flock requires fp")); 357 if (fp->f_type != DTYPE_NONE && fp->f_type != DTYPE_VNODE) 358 return (EOPNOTSUPP); 359 360 lock_flags = VOP_ISLOCKED(vp); 361 VOP_UNLOCK(vp); 362 363 lf.l_whence = SEEK_SET; 364 lf.l_start = 0; 365 lf.l_len = 0; 366 lf.l_type = (fmode & O_EXLOCK) != 0 ? F_WRLCK : F_RDLCK; 367 type = F_FLOCK; 368 if ((fmode & FNONBLOCK) == 0) 369 type |= F_WAIT; 370 if ((fmode & (O_CREAT | O_EXCL)) == (O_CREAT | O_EXCL)) 371 type |= F_FIRSTOPEN; 372 error = VOP_ADVLOCK(vp, (caddr_t)fp, F_SETLK, &lf, type); 373 if (error == 0) 374 fp->f_flag |= FHASLOCK; 375 376 vn_lock(vp, lock_flags | LK_RETRY); 377 return (error); 378 } 379 380 /* 381 * Common code for vnode open operations once a vnode is located. 382 * Check permissions, and call the VOP_OPEN routine. 383 */ 384 int 385 vn_open_vnode(struct vnode *vp, int fmode, struct ucred *cred, 386 struct thread *td, struct file *fp) 387 { 388 accmode_t accmode; 389 int error; 390 391 if (vp->v_type == VLNK) { 392 if ((fmode & O_PATH) == 0 || (fmode & FEXEC) != 0) 393 return (EMLINK); 394 } 395 if (vp->v_type == VSOCK) 396 return (EOPNOTSUPP); 397 if (vp->v_type != VDIR && fmode & O_DIRECTORY) 398 return (ENOTDIR); 399 400 accmode = 0; 401 if ((fmode & O_PATH) == 0) { 402 if ((fmode & (FWRITE | O_TRUNC)) != 0) { 403 if (vp->v_type == VDIR) 404 return (EISDIR); 405 accmode |= VWRITE; 406 } 407 if ((fmode & FREAD) != 0) 408 accmode |= VREAD; 409 if ((fmode & O_APPEND) && (fmode & FWRITE)) 410 accmode |= VAPPEND; 411 #ifdef MAC 412 if ((fmode & O_CREAT) != 0) 413 accmode |= VCREAT; 414 #endif 415 } 416 if ((fmode & FEXEC) != 0) 417 accmode |= VEXEC; 418 #ifdef MAC 419 if ((fmode & O_VERIFY) != 0) 420 accmode |= VVERIFY; 421 error = mac_vnode_check_open(cred, vp, accmode); 422 if (error != 0) 423 return (error); 424 425 accmode &= ~(VCREAT | VVERIFY); 426 #endif 427 if ((fmode & O_CREAT) == 0 && accmode != 0) { 428 error = VOP_ACCESS(vp, accmode, cred, td); 429 if (error != 0) 430 return (error); 431 } 432 if ((fmode & O_PATH) != 0) { 433 if (vp->v_type == VFIFO) 434 error = EPIPE; 435 else 436 error = VOP_ACCESS(vp, VREAD, cred, td); 437 if (error == 0) 438 fp->f_flag |= FKQALLOWED; 439 return (0); 440 } 441 442 if (vp->v_type == VFIFO && VOP_ISLOCKED(vp) != LK_EXCLUSIVE) 443 vn_lock(vp, LK_UPGRADE | LK_RETRY); 444 error = VOP_OPEN(vp, fmode, cred, td, fp); 445 if (error != 0) 446 return (error); 447 448 error = vn_open_vnode_advlock(vp, fmode, fp); 449 if (error == 0 && (fmode & FWRITE) != 0) { 450 error = VOP_ADD_WRITECOUNT(vp, 1); 451 if (error == 0) { 452 CTR3(KTR_VFS, "%s: vp %p v_writecount increased to %d", 453 __func__, vp, vp->v_writecount); 454 } 455 } 456 457 /* 458 * Error from advlock or VOP_ADD_WRITECOUNT() still requires 459 * calling VOP_CLOSE() to pair with earlier VOP_OPEN(). 460 */ 461 if (error != 0) { 462 if (fp != NULL) { 463 /* 464 * Arrange the call by having fdrop() to use 465 * vn_closefile(). This is to satisfy 466 * filesystems like devfs or tmpfs, which 467 * override fo_close(). 468 */ 469 fp->f_flag |= FOPENFAILED; 470 fp->f_vnode = vp; 471 if (fp->f_ops == &badfileops) { 472 fp->f_type = DTYPE_VNODE; 473 fp->f_ops = &vnops; 474 } 475 vref(vp); 476 } else { 477 /* 478 * If there is no fp, due to kernel-mode open, 479 * we can call VOP_CLOSE() now. 480 */ 481 if (vp->v_type != VFIFO && (fmode & FWRITE) != 0 && 482 !MNT_EXTENDED_SHARED(vp->v_mount) && 483 VOP_ISLOCKED(vp) != LK_EXCLUSIVE) 484 vn_lock(vp, LK_UPGRADE | LK_RETRY); 485 (void)VOP_CLOSE(vp, fmode & (FREAD | FWRITE | FEXEC), 486 cred, td); 487 } 488 } 489 490 ASSERT_VOP_LOCKED(vp, "vn_open_vnode"); 491 return (error); 492 493 } 494 495 /* 496 * Check for write permissions on the specified vnode. 497 * Prototype text segments cannot be written. 498 * It is racy. 499 */ 500 int 501 vn_writechk(struct vnode *vp) 502 { 503 504 ASSERT_VOP_LOCKED(vp, "vn_writechk"); 505 /* 506 * If there's shared text associated with 507 * the vnode, try to free it up once. If 508 * we fail, we can't allow writing. 509 */ 510 if (VOP_IS_TEXT(vp)) 511 return (ETXTBSY); 512 513 return (0); 514 } 515 516 /* 517 * Vnode close call 518 */ 519 static int 520 vn_close1(struct vnode *vp, int flags, struct ucred *file_cred, 521 struct thread *td, bool keep_ref) 522 { 523 struct mount *mp; 524 int error, lock_flags; 525 526 if (vp->v_type != VFIFO && (flags & FWRITE) == 0 && 527 MNT_EXTENDED_SHARED(vp->v_mount)) 528 lock_flags = LK_SHARED; 529 else 530 lock_flags = LK_EXCLUSIVE; 531 532 vn_start_write(vp, &mp, V_WAIT); 533 vn_lock(vp, lock_flags | LK_RETRY); 534 AUDIT_ARG_VNODE1(vp); 535 if ((flags & (FWRITE | FOPENFAILED)) == FWRITE) { 536 VOP_ADD_WRITECOUNT_CHECKED(vp, -1); 537 CTR3(KTR_VFS, "%s: vp %p v_writecount decreased to %d", 538 __func__, vp, vp->v_writecount); 539 } 540 error = VOP_CLOSE(vp, flags, file_cred, td); 541 if (keep_ref) 542 VOP_UNLOCK(vp); 543 else 544 vput(vp); 545 vn_finished_write(mp); 546 return (error); 547 } 548 549 int 550 vn_close(struct vnode *vp, int flags, struct ucred *file_cred, 551 struct thread *td) 552 { 553 554 return (vn_close1(vp, flags, file_cred, td, false)); 555 } 556 557 /* 558 * Heuristic to detect sequential operation. 559 */ 560 static int 561 sequential_heuristic(struct uio *uio, struct file *fp) 562 { 563 enum uio_rw rw; 564 565 ASSERT_VOP_LOCKED(fp->f_vnode, __func__); 566 567 rw = uio->uio_rw; 568 if (fp->f_flag & FRDAHEAD) 569 return (fp->f_seqcount[rw] << IO_SEQSHIFT); 570 571 /* 572 * Offset 0 is handled specially. open() sets f_seqcount to 1 so 573 * that the first I/O is normally considered to be slightly 574 * sequential. Seeking to offset 0 doesn't change sequentiality 575 * unless previous seeks have reduced f_seqcount to 0, in which 576 * case offset 0 is not special. 577 */ 578 if ((uio->uio_offset == 0 && fp->f_seqcount[rw] > 0) || 579 uio->uio_offset == fp->f_nextoff[rw]) { 580 /* 581 * f_seqcount is in units of fixed-size blocks so that it 582 * depends mainly on the amount of sequential I/O and not 583 * much on the number of sequential I/O's. The fixed size 584 * of 16384 is hard-coded here since it is (not quite) just 585 * a magic size that works well here. This size is more 586 * closely related to the best I/O size for real disks than 587 * to any block size used by software. 588 */ 589 if (uio->uio_resid >= IO_SEQMAX * 16384) 590 fp->f_seqcount[rw] = IO_SEQMAX; 591 else { 592 fp->f_seqcount[rw] += howmany(uio->uio_resid, 16384); 593 if (fp->f_seqcount[rw] > IO_SEQMAX) 594 fp->f_seqcount[rw] = IO_SEQMAX; 595 } 596 return (fp->f_seqcount[rw] << IO_SEQSHIFT); 597 } 598 599 /* Not sequential. Quickly draw-down sequentiality. */ 600 if (fp->f_seqcount[rw] > 1) 601 fp->f_seqcount[rw] = 1; 602 else 603 fp->f_seqcount[rw] = 0; 604 return (0); 605 } 606 607 /* 608 * Package up an I/O request on a vnode into a uio and do it. 609 */ 610 int 611 vn_rdwr(enum uio_rw rw, struct vnode *vp, void *base, int len, off_t offset, 612 enum uio_seg segflg, int ioflg, struct ucred *active_cred, 613 struct ucred *file_cred, ssize_t *aresid, struct thread *td) 614 { 615 struct uio auio; 616 struct iovec aiov; 617 struct mount *mp; 618 struct ucred *cred; 619 void *rl_cookie; 620 struct vn_io_fault_args args; 621 int error, lock_flags; 622 623 if (offset < 0 && vp->v_type != VCHR) 624 return (EINVAL); 625 auio.uio_iov = &aiov; 626 auio.uio_iovcnt = 1; 627 aiov.iov_base = base; 628 aiov.iov_len = len; 629 auio.uio_resid = len; 630 auio.uio_offset = offset; 631 auio.uio_segflg = segflg; 632 auio.uio_rw = rw; 633 auio.uio_td = td; 634 error = 0; 635 636 if ((ioflg & IO_NODELOCKED) == 0) { 637 if ((ioflg & IO_RANGELOCKED) == 0) { 638 if (rw == UIO_READ) { 639 rl_cookie = vn_rangelock_rlock(vp, offset, 640 offset + len); 641 } else if ((ioflg & IO_APPEND) != 0) { 642 rl_cookie = vn_rangelock_wlock(vp, 0, OFF_MAX); 643 } else { 644 rl_cookie = vn_rangelock_wlock(vp, offset, 645 offset + len); 646 } 647 } else 648 rl_cookie = NULL; 649 mp = NULL; 650 if (rw == UIO_WRITE) { 651 if (vp->v_type != VCHR && 652 (error = vn_start_write(vp, &mp, V_WAIT | PCATCH)) 653 != 0) 654 goto out; 655 if (MNT_SHARED_WRITES(mp) || 656 ((mp == NULL) && MNT_SHARED_WRITES(vp->v_mount))) 657 lock_flags = LK_SHARED; 658 else 659 lock_flags = LK_EXCLUSIVE; 660 } else 661 lock_flags = LK_SHARED; 662 vn_lock(vp, lock_flags | LK_RETRY); 663 } else 664 rl_cookie = NULL; 665 666 ASSERT_VOP_LOCKED(vp, "IO_NODELOCKED with no vp lock held"); 667 #ifdef MAC 668 if ((ioflg & IO_NOMACCHECK) == 0) { 669 if (rw == UIO_READ) 670 error = mac_vnode_check_read(active_cred, file_cred, 671 vp); 672 else 673 error = mac_vnode_check_write(active_cred, file_cred, 674 vp); 675 } 676 #endif 677 if (error == 0) { 678 if (file_cred != NULL) 679 cred = file_cred; 680 else 681 cred = active_cred; 682 if (do_vn_io_fault(vp, &auio)) { 683 args.kind = VN_IO_FAULT_VOP; 684 args.cred = cred; 685 args.flags = ioflg; 686 args.args.vop_args.vp = vp; 687 error = vn_io_fault1(vp, &auio, &args, td); 688 } else if (rw == UIO_READ) { 689 error = VOP_READ(vp, &auio, ioflg, cred); 690 } else /* if (rw == UIO_WRITE) */ { 691 error = VOP_WRITE(vp, &auio, ioflg, cred); 692 } 693 } 694 if (aresid) 695 *aresid = auio.uio_resid; 696 else 697 if (auio.uio_resid && error == 0) 698 error = EIO; 699 if ((ioflg & IO_NODELOCKED) == 0) { 700 VOP_UNLOCK(vp); 701 if (mp != NULL) 702 vn_finished_write(mp); 703 } 704 out: 705 if (rl_cookie != NULL) 706 vn_rangelock_unlock(vp, rl_cookie); 707 return (error); 708 } 709 710 /* 711 * Package up an I/O request on a vnode into a uio and do it. The I/O 712 * request is split up into smaller chunks and we try to avoid saturating 713 * the buffer cache while potentially holding a vnode locked, so we 714 * check bwillwrite() before calling vn_rdwr(). We also call kern_yield() 715 * to give other processes a chance to lock the vnode (either other processes 716 * core'ing the same binary, or unrelated processes scanning the directory). 717 */ 718 int 719 vn_rdwr_inchunks(enum uio_rw rw, struct vnode *vp, void *base, size_t len, 720 off_t offset, enum uio_seg segflg, int ioflg, struct ucred *active_cred, 721 struct ucred *file_cred, size_t *aresid, struct thread *td) 722 { 723 int error = 0; 724 ssize_t iaresid; 725 726 do { 727 int chunk; 728 729 /* 730 * Force `offset' to a multiple of MAXBSIZE except possibly 731 * for the first chunk, so that filesystems only need to 732 * write full blocks except possibly for the first and last 733 * chunks. 734 */ 735 chunk = MAXBSIZE - (uoff_t)offset % MAXBSIZE; 736 737 if (chunk > len) 738 chunk = len; 739 if (rw != UIO_READ && vp->v_type == VREG) 740 bwillwrite(); 741 iaresid = 0; 742 error = vn_rdwr(rw, vp, base, chunk, offset, segflg, 743 ioflg, active_cred, file_cred, &iaresid, td); 744 len -= chunk; /* aresid calc already includes length */ 745 if (error) 746 break; 747 offset += chunk; 748 base = (char *)base + chunk; 749 kern_yield(PRI_USER); 750 } while (len); 751 if (aresid) 752 *aresid = len + iaresid; 753 return (error); 754 } 755 756 #if OFF_MAX <= LONG_MAX 757 off_t 758 foffset_lock(struct file *fp, int flags) 759 { 760 volatile short *flagsp; 761 off_t res; 762 short state; 763 764 KASSERT((flags & FOF_OFFSET) == 0, ("FOF_OFFSET passed")); 765 766 if ((flags & FOF_NOLOCK) != 0) 767 return (atomic_load_long(&fp->f_offset)); 768 769 /* 770 * According to McKusick the vn lock was protecting f_offset here. 771 * It is now protected by the FOFFSET_LOCKED flag. 772 */ 773 flagsp = &fp->f_vnread_flags; 774 if (atomic_cmpset_acq_16(flagsp, 0, FOFFSET_LOCKED)) 775 return (atomic_load_long(&fp->f_offset)); 776 777 sleepq_lock(&fp->f_vnread_flags); 778 state = atomic_load_16(flagsp); 779 for (;;) { 780 if ((state & FOFFSET_LOCKED) == 0) { 781 if (!atomic_fcmpset_acq_16(flagsp, &state, 782 FOFFSET_LOCKED)) 783 continue; 784 break; 785 } 786 if ((state & FOFFSET_LOCK_WAITING) == 0) { 787 if (!atomic_fcmpset_acq_16(flagsp, &state, 788 state | FOFFSET_LOCK_WAITING)) 789 continue; 790 } 791 DROP_GIANT(); 792 sleepq_add(&fp->f_vnread_flags, NULL, "vofflock", 0, 0); 793 sleepq_wait(&fp->f_vnread_flags, PUSER -1); 794 PICKUP_GIANT(); 795 sleepq_lock(&fp->f_vnread_flags); 796 state = atomic_load_16(flagsp); 797 } 798 res = atomic_load_long(&fp->f_offset); 799 sleepq_release(&fp->f_vnread_flags); 800 return (res); 801 } 802 803 void 804 foffset_unlock(struct file *fp, off_t val, int flags) 805 { 806 volatile short *flagsp; 807 short state; 808 809 KASSERT((flags & FOF_OFFSET) == 0, ("FOF_OFFSET passed")); 810 811 if ((flags & FOF_NOUPDATE) == 0) 812 atomic_store_long(&fp->f_offset, val); 813 if ((flags & FOF_NEXTOFF_R) != 0) 814 fp->f_nextoff[UIO_READ] = val; 815 if ((flags & FOF_NEXTOFF_W) != 0) 816 fp->f_nextoff[UIO_WRITE] = val; 817 818 if ((flags & FOF_NOLOCK) != 0) 819 return; 820 821 flagsp = &fp->f_vnread_flags; 822 state = atomic_load_16(flagsp); 823 if ((state & FOFFSET_LOCK_WAITING) == 0 && 824 atomic_cmpset_rel_16(flagsp, state, 0)) 825 return; 826 827 sleepq_lock(&fp->f_vnread_flags); 828 MPASS((fp->f_vnread_flags & FOFFSET_LOCKED) != 0); 829 MPASS((fp->f_vnread_flags & FOFFSET_LOCK_WAITING) != 0); 830 fp->f_vnread_flags = 0; 831 sleepq_broadcast(&fp->f_vnread_flags, SLEEPQ_SLEEP, 0, 0); 832 sleepq_release(&fp->f_vnread_flags); 833 } 834 #else 835 off_t 836 foffset_lock(struct file *fp, int flags) 837 { 838 struct mtx *mtxp; 839 off_t res; 840 841 KASSERT((flags & FOF_OFFSET) == 0, ("FOF_OFFSET passed")); 842 843 mtxp = mtx_pool_find(mtxpool_sleep, fp); 844 mtx_lock(mtxp); 845 if ((flags & FOF_NOLOCK) == 0) { 846 while (fp->f_vnread_flags & FOFFSET_LOCKED) { 847 fp->f_vnread_flags |= FOFFSET_LOCK_WAITING; 848 msleep(&fp->f_vnread_flags, mtxp, PUSER -1, 849 "vofflock", 0); 850 } 851 fp->f_vnread_flags |= FOFFSET_LOCKED; 852 } 853 res = fp->f_offset; 854 mtx_unlock(mtxp); 855 return (res); 856 } 857 858 void 859 foffset_unlock(struct file *fp, off_t val, int flags) 860 { 861 struct mtx *mtxp; 862 863 KASSERT((flags & FOF_OFFSET) == 0, ("FOF_OFFSET passed")); 864 865 mtxp = mtx_pool_find(mtxpool_sleep, fp); 866 mtx_lock(mtxp); 867 if ((flags & FOF_NOUPDATE) == 0) 868 fp->f_offset = val; 869 if ((flags & FOF_NEXTOFF_R) != 0) 870 fp->f_nextoff[UIO_READ] = val; 871 if ((flags & FOF_NEXTOFF_W) != 0) 872 fp->f_nextoff[UIO_WRITE] = val; 873 if ((flags & FOF_NOLOCK) == 0) { 874 KASSERT((fp->f_vnread_flags & FOFFSET_LOCKED) != 0, 875 ("Lost FOFFSET_LOCKED")); 876 if (fp->f_vnread_flags & FOFFSET_LOCK_WAITING) 877 wakeup(&fp->f_vnread_flags); 878 fp->f_vnread_flags = 0; 879 } 880 mtx_unlock(mtxp); 881 } 882 #endif 883 884 void 885 foffset_lock_uio(struct file *fp, struct uio *uio, int flags) 886 { 887 888 if ((flags & FOF_OFFSET) == 0) 889 uio->uio_offset = foffset_lock(fp, flags); 890 } 891 892 void 893 foffset_unlock_uio(struct file *fp, struct uio *uio, int flags) 894 { 895 896 if ((flags & FOF_OFFSET) == 0) 897 foffset_unlock(fp, uio->uio_offset, flags); 898 } 899 900 static int 901 get_advice(struct file *fp, struct uio *uio) 902 { 903 struct mtx *mtxp; 904 int ret; 905 906 ret = POSIX_FADV_NORMAL; 907 if (fp->f_advice == NULL || fp->f_vnode->v_type != VREG) 908 return (ret); 909 910 mtxp = mtx_pool_find(mtxpool_sleep, fp); 911 mtx_lock(mtxp); 912 if (fp->f_advice != NULL && 913 uio->uio_offset >= fp->f_advice->fa_start && 914 uio->uio_offset + uio->uio_resid <= fp->f_advice->fa_end) 915 ret = fp->f_advice->fa_advice; 916 mtx_unlock(mtxp); 917 return (ret); 918 } 919 920 int 921 vn_read_from_obj(struct vnode *vp, struct uio *uio) 922 { 923 vm_object_t obj; 924 vm_page_t ma[io_hold_cnt + 2]; 925 off_t off, vsz; 926 ssize_t resid; 927 int error, i, j; 928 929 MPASS(uio->uio_resid <= ptoa(io_hold_cnt + 2)); 930 obj = atomic_load_ptr(&vp->v_object); 931 if (obj == NULL) 932 return (EJUSTRETURN); 933 934 /* 935 * Depends on type stability of vm_objects. 936 */ 937 vm_object_pip_add(obj, 1); 938 if ((obj->flags & OBJ_DEAD) != 0) { 939 /* 940 * Note that object might be already reused from the 941 * vnode, and the OBJ_DEAD flag cleared. This is fine, 942 * we recheck for DOOMED vnode state after all pages 943 * are busied, and retract then. 944 * 945 * But we check for OBJ_DEAD to ensure that we do not 946 * busy pages while vm_object_terminate_pages() 947 * processes the queue. 948 */ 949 error = EJUSTRETURN; 950 goto out_pip; 951 } 952 953 resid = uio->uio_resid; 954 off = uio->uio_offset; 955 for (i = 0; resid > 0; i++) { 956 MPASS(i < io_hold_cnt + 2); 957 ma[i] = vm_page_grab_unlocked(obj, atop(off), 958 VM_ALLOC_NOCREAT | VM_ALLOC_SBUSY | VM_ALLOC_IGN_SBUSY | 959 VM_ALLOC_NOWAIT); 960 if (ma[i] == NULL) 961 break; 962 963 /* 964 * Skip invalid pages. Valid mask can be partial only 965 * at EOF, and we clip later. 966 */ 967 if (vm_page_none_valid(ma[i])) { 968 vm_page_sunbusy(ma[i]); 969 break; 970 } 971 972 resid -= PAGE_SIZE; 973 off += PAGE_SIZE; 974 } 975 if (i == 0) { 976 error = EJUSTRETURN; 977 goto out_pip; 978 } 979 980 /* 981 * Check VIRF_DOOMED after we busied our pages. Since 982 * vgonel() terminates the vnode' vm_object, it cannot 983 * process past pages busied by us. 984 */ 985 if (VN_IS_DOOMED(vp)) { 986 error = EJUSTRETURN; 987 goto out; 988 } 989 990 resid = PAGE_SIZE - (uio->uio_offset & PAGE_MASK) + ptoa(i - 1); 991 if (resid > uio->uio_resid) 992 resid = uio->uio_resid; 993 994 /* 995 * Unlocked read of vnp_size is safe because truncation cannot 996 * pass busied page. But we load vnp_size into a local 997 * variable so that possible concurrent extension does not 998 * break calculation. 999 */ 1000 #if defined(__powerpc__) && !defined(__powerpc64__) 1001 vsz = obj->un_pager.vnp.vnp_size; 1002 #else 1003 vsz = atomic_load_64(&obj->un_pager.vnp.vnp_size); 1004 #endif 1005 if (uio->uio_offset >= vsz) { 1006 error = EJUSTRETURN; 1007 goto out; 1008 } 1009 if (uio->uio_offset + resid > vsz) 1010 resid = vsz - uio->uio_offset; 1011 1012 error = vn_io_fault_pgmove(ma, uio->uio_offset & PAGE_MASK, resid, uio); 1013 1014 out: 1015 for (j = 0; j < i; j++) { 1016 if (error == 0) 1017 vm_page_reference(ma[j]); 1018 vm_page_sunbusy(ma[j]); 1019 } 1020 out_pip: 1021 vm_object_pip_wakeup(obj); 1022 if (error != 0) 1023 return (error); 1024 return (uio->uio_resid == 0 ? 0 : EJUSTRETURN); 1025 } 1026 1027 /* 1028 * File table vnode read routine. 1029 */ 1030 static int 1031 vn_read(struct file *fp, struct uio *uio, struct ucred *active_cred, int flags, 1032 struct thread *td) 1033 { 1034 struct vnode *vp; 1035 off_t orig_offset; 1036 int error, ioflag; 1037 int advice; 1038 1039 KASSERT(uio->uio_td == td, ("uio_td %p is not td %p", 1040 uio->uio_td, td)); 1041 KASSERT(flags & FOF_OFFSET, ("No FOF_OFFSET")); 1042 vp = fp->f_vnode; 1043 ioflag = 0; 1044 if (fp->f_flag & FNONBLOCK) 1045 ioflag |= IO_NDELAY; 1046 if (fp->f_flag & O_DIRECT) 1047 ioflag |= IO_DIRECT; 1048 1049 /* 1050 * Try to read from page cache. VIRF_DOOMED check is racy but 1051 * allows us to avoid unneeded work outright. 1052 */ 1053 if (vn_io_pgcache_read_enable && !mac_vnode_check_read_enabled() && 1054 (vn_irflag_read(vp) & (VIRF_DOOMED | VIRF_PGREAD)) == VIRF_PGREAD) { 1055 error = VOP_READ_PGCACHE(vp, uio, ioflag, fp->f_cred); 1056 if (error == 0) { 1057 fp->f_nextoff[UIO_READ] = uio->uio_offset; 1058 return (0); 1059 } 1060 if (error != EJUSTRETURN) 1061 return (error); 1062 } 1063 1064 advice = get_advice(fp, uio); 1065 vn_lock(vp, LK_SHARED | LK_RETRY); 1066 1067 switch (advice) { 1068 case POSIX_FADV_NORMAL: 1069 case POSIX_FADV_SEQUENTIAL: 1070 case POSIX_FADV_NOREUSE: 1071 ioflag |= sequential_heuristic(uio, fp); 1072 break; 1073 case POSIX_FADV_RANDOM: 1074 /* Disable read-ahead for random I/O. */ 1075 break; 1076 } 1077 orig_offset = uio->uio_offset; 1078 1079 #ifdef MAC 1080 error = mac_vnode_check_read(active_cred, fp->f_cred, vp); 1081 if (error == 0) 1082 #endif 1083 error = VOP_READ(vp, uio, ioflag, fp->f_cred); 1084 fp->f_nextoff[UIO_READ] = uio->uio_offset; 1085 VOP_UNLOCK(vp); 1086 if (error == 0 && advice == POSIX_FADV_NOREUSE && 1087 orig_offset != uio->uio_offset) 1088 /* 1089 * Use POSIX_FADV_DONTNEED to flush pages and buffers 1090 * for the backing file after a POSIX_FADV_NOREUSE 1091 * read(2). 1092 */ 1093 error = VOP_ADVISE(vp, orig_offset, uio->uio_offset - 1, 1094 POSIX_FADV_DONTNEED); 1095 return (error); 1096 } 1097 1098 /* 1099 * File table vnode write routine. 1100 */ 1101 static int 1102 vn_write(struct file *fp, struct uio *uio, struct ucred *active_cred, int flags, 1103 struct thread *td) 1104 { 1105 struct vnode *vp; 1106 struct mount *mp; 1107 off_t orig_offset; 1108 int error, ioflag, lock_flags; 1109 int advice; 1110 1111 KASSERT(uio->uio_td == td, ("uio_td %p is not td %p", 1112 uio->uio_td, td)); 1113 KASSERT(flags & FOF_OFFSET, ("No FOF_OFFSET")); 1114 vp = fp->f_vnode; 1115 if (vp->v_type == VREG) 1116 bwillwrite(); 1117 ioflag = IO_UNIT; 1118 if (vp->v_type == VREG && (fp->f_flag & O_APPEND)) 1119 ioflag |= IO_APPEND; 1120 if (fp->f_flag & FNONBLOCK) 1121 ioflag |= IO_NDELAY; 1122 if (fp->f_flag & O_DIRECT) 1123 ioflag |= IO_DIRECT; 1124 if ((fp->f_flag & O_FSYNC) || 1125 (vp->v_mount && (vp->v_mount->mnt_flag & MNT_SYNCHRONOUS))) 1126 ioflag |= IO_SYNC; 1127 /* 1128 * For O_DSYNC we set both IO_SYNC and IO_DATASYNC, so that VOP_WRITE() 1129 * implementations that don't understand IO_DATASYNC fall back to full 1130 * O_SYNC behavior. 1131 */ 1132 if (fp->f_flag & O_DSYNC) 1133 ioflag |= IO_SYNC | IO_DATASYNC; 1134 mp = NULL; 1135 if (vp->v_type != VCHR && 1136 (error = vn_start_write(vp, &mp, V_WAIT | PCATCH)) != 0) 1137 goto unlock; 1138 1139 advice = get_advice(fp, uio); 1140 1141 if (MNT_SHARED_WRITES(mp) || 1142 (mp == NULL && MNT_SHARED_WRITES(vp->v_mount))) { 1143 lock_flags = LK_SHARED; 1144 } else { 1145 lock_flags = LK_EXCLUSIVE; 1146 } 1147 1148 vn_lock(vp, lock_flags | LK_RETRY); 1149 switch (advice) { 1150 case POSIX_FADV_NORMAL: 1151 case POSIX_FADV_SEQUENTIAL: 1152 case POSIX_FADV_NOREUSE: 1153 ioflag |= sequential_heuristic(uio, fp); 1154 break; 1155 case POSIX_FADV_RANDOM: 1156 /* XXX: Is this correct? */ 1157 break; 1158 } 1159 orig_offset = uio->uio_offset; 1160 1161 #ifdef MAC 1162 error = mac_vnode_check_write(active_cred, fp->f_cred, vp); 1163 if (error == 0) 1164 #endif 1165 error = VOP_WRITE(vp, uio, ioflag, fp->f_cred); 1166 fp->f_nextoff[UIO_WRITE] = uio->uio_offset; 1167 VOP_UNLOCK(vp); 1168 if (vp->v_type != VCHR) 1169 vn_finished_write(mp); 1170 if (error == 0 && advice == POSIX_FADV_NOREUSE && 1171 orig_offset != uio->uio_offset) 1172 /* 1173 * Use POSIX_FADV_DONTNEED to flush pages and buffers 1174 * for the backing file after a POSIX_FADV_NOREUSE 1175 * write(2). 1176 */ 1177 error = VOP_ADVISE(vp, orig_offset, uio->uio_offset - 1, 1178 POSIX_FADV_DONTNEED); 1179 unlock: 1180 return (error); 1181 } 1182 1183 /* 1184 * The vn_io_fault() is a wrapper around vn_read() and vn_write() to 1185 * prevent the following deadlock: 1186 * 1187 * Assume that the thread A reads from the vnode vp1 into userspace 1188 * buffer buf1 backed by the pages of vnode vp2. If a page in buf1 is 1189 * currently not resident, then system ends up with the call chain 1190 * vn_read() -> VOP_READ(vp1) -> uiomove() -> [Page Fault] -> 1191 * vm_fault(buf1) -> vnode_pager_getpages(vp2) -> VOP_GETPAGES(vp2) 1192 * which establishes lock order vp1->vn_lock, then vp2->vn_lock. 1193 * If, at the same time, thread B reads from vnode vp2 into buffer buf2 1194 * backed by the pages of vnode vp1, and some page in buf2 is not 1195 * resident, we get a reversed order vp2->vn_lock, then vp1->vn_lock. 1196 * 1197 * To prevent the lock order reversal and deadlock, vn_io_fault() does 1198 * not allow page faults to happen during VOP_READ() or VOP_WRITE(). 1199 * Instead, it first tries to do the whole range i/o with pagefaults 1200 * disabled. If all pages in the i/o buffer are resident and mapped, 1201 * VOP will succeed (ignoring the genuine filesystem errors). 1202 * Otherwise, we get back EFAULT, and vn_io_fault() falls back to do 1203 * i/o in chunks, with all pages in the chunk prefaulted and held 1204 * using vm_fault_quick_hold_pages(). 1205 * 1206 * Filesystems using this deadlock avoidance scheme should use the 1207 * array of the held pages from uio, saved in the curthread->td_ma, 1208 * instead of doing uiomove(). A helper function 1209 * vn_io_fault_uiomove() converts uiomove request into 1210 * uiomove_fromphys() over td_ma array. 1211 * 1212 * Since vnode locks do not cover the whole i/o anymore, rangelocks 1213 * make the current i/o request atomic with respect to other i/os and 1214 * truncations. 1215 */ 1216 1217 /* 1218 * Decode vn_io_fault_args and perform the corresponding i/o. 1219 */ 1220 static int 1221 vn_io_fault_doio(struct vn_io_fault_args *args, struct uio *uio, 1222 struct thread *td) 1223 { 1224 int error, save; 1225 1226 error = 0; 1227 save = vm_fault_disable_pagefaults(); 1228 switch (args->kind) { 1229 case VN_IO_FAULT_FOP: 1230 error = (args->args.fop_args.doio)(args->args.fop_args.fp, 1231 uio, args->cred, args->flags, td); 1232 break; 1233 case VN_IO_FAULT_VOP: 1234 if (uio->uio_rw == UIO_READ) { 1235 error = VOP_READ(args->args.vop_args.vp, uio, 1236 args->flags, args->cred); 1237 } else if (uio->uio_rw == UIO_WRITE) { 1238 error = VOP_WRITE(args->args.vop_args.vp, uio, 1239 args->flags, args->cred); 1240 } 1241 break; 1242 default: 1243 panic("vn_io_fault_doio: unknown kind of io %d %d", 1244 args->kind, uio->uio_rw); 1245 } 1246 vm_fault_enable_pagefaults(save); 1247 return (error); 1248 } 1249 1250 static int 1251 vn_io_fault_touch(char *base, const struct uio *uio) 1252 { 1253 int r; 1254 1255 r = fubyte(base); 1256 if (r == -1 || (uio->uio_rw == UIO_READ && subyte(base, r) == -1)) 1257 return (EFAULT); 1258 return (0); 1259 } 1260 1261 static int 1262 vn_io_fault_prefault_user(const struct uio *uio) 1263 { 1264 char *base; 1265 const struct iovec *iov; 1266 size_t len; 1267 ssize_t resid; 1268 int error, i; 1269 1270 KASSERT(uio->uio_segflg == UIO_USERSPACE, 1271 ("vn_io_fault_prefault userspace")); 1272 1273 error = i = 0; 1274 iov = uio->uio_iov; 1275 resid = uio->uio_resid; 1276 base = iov->iov_base; 1277 len = iov->iov_len; 1278 while (resid > 0) { 1279 error = vn_io_fault_touch(base, uio); 1280 if (error != 0) 1281 break; 1282 if (len < PAGE_SIZE) { 1283 if (len != 0) { 1284 error = vn_io_fault_touch(base + len - 1, uio); 1285 if (error != 0) 1286 break; 1287 resid -= len; 1288 } 1289 if (++i >= uio->uio_iovcnt) 1290 break; 1291 iov = uio->uio_iov + i; 1292 base = iov->iov_base; 1293 len = iov->iov_len; 1294 } else { 1295 len -= PAGE_SIZE; 1296 base += PAGE_SIZE; 1297 resid -= PAGE_SIZE; 1298 } 1299 } 1300 return (error); 1301 } 1302 1303 /* 1304 * Common code for vn_io_fault(), agnostic to the kind of i/o request. 1305 * Uses vn_io_fault_doio() to make the call to an actual i/o function. 1306 * Used from vn_rdwr() and vn_io_fault(), which encode the i/o request 1307 * into args and call vn_io_fault1() to handle faults during the user 1308 * mode buffer accesses. 1309 */ 1310 static int 1311 vn_io_fault1(struct vnode *vp, struct uio *uio, struct vn_io_fault_args *args, 1312 struct thread *td) 1313 { 1314 vm_page_t ma[io_hold_cnt + 2]; 1315 struct uio *uio_clone, short_uio; 1316 struct iovec short_iovec[1]; 1317 vm_page_t *prev_td_ma; 1318 vm_prot_t prot; 1319 vm_offset_t addr, end; 1320 size_t len, resid; 1321 ssize_t adv; 1322 int error, cnt, saveheld, prev_td_ma_cnt; 1323 1324 if (vn_io_fault_prefault) { 1325 error = vn_io_fault_prefault_user(uio); 1326 if (error != 0) 1327 return (error); /* Or ignore ? */ 1328 } 1329 1330 prot = uio->uio_rw == UIO_READ ? VM_PROT_WRITE : VM_PROT_READ; 1331 1332 /* 1333 * The UFS follows IO_UNIT directive and replays back both 1334 * uio_offset and uio_resid if an error is encountered during the 1335 * operation. But, since the iovec may be already advanced, 1336 * uio is still in an inconsistent state. 1337 * 1338 * Cache a copy of the original uio, which is advanced to the redo 1339 * point using UIO_NOCOPY below. 1340 */ 1341 uio_clone = cloneuio(uio); 1342 resid = uio->uio_resid; 1343 1344 short_uio.uio_segflg = UIO_USERSPACE; 1345 short_uio.uio_rw = uio->uio_rw; 1346 short_uio.uio_td = uio->uio_td; 1347 1348 error = vn_io_fault_doio(args, uio, td); 1349 if (error != EFAULT) 1350 goto out; 1351 1352 atomic_add_long(&vn_io_faults_cnt, 1); 1353 uio_clone->uio_segflg = UIO_NOCOPY; 1354 uiomove(NULL, resid - uio->uio_resid, uio_clone); 1355 uio_clone->uio_segflg = uio->uio_segflg; 1356 1357 saveheld = curthread_pflags_set(TDP_UIOHELD); 1358 prev_td_ma = td->td_ma; 1359 prev_td_ma_cnt = td->td_ma_cnt; 1360 1361 while (uio_clone->uio_resid != 0) { 1362 len = uio_clone->uio_iov->iov_len; 1363 if (len == 0) { 1364 KASSERT(uio_clone->uio_iovcnt >= 1, 1365 ("iovcnt underflow")); 1366 uio_clone->uio_iov++; 1367 uio_clone->uio_iovcnt--; 1368 continue; 1369 } 1370 if (len > ptoa(io_hold_cnt)) 1371 len = ptoa(io_hold_cnt); 1372 addr = (uintptr_t)uio_clone->uio_iov->iov_base; 1373 end = round_page(addr + len); 1374 if (end < addr) { 1375 error = EFAULT; 1376 break; 1377 } 1378 cnt = atop(end - trunc_page(addr)); 1379 /* 1380 * A perfectly misaligned address and length could cause 1381 * both the start and the end of the chunk to use partial 1382 * page. +2 accounts for such a situation. 1383 */ 1384 cnt = vm_fault_quick_hold_pages(&td->td_proc->p_vmspace->vm_map, 1385 addr, len, prot, ma, io_hold_cnt + 2); 1386 if (cnt == -1) { 1387 error = EFAULT; 1388 break; 1389 } 1390 short_uio.uio_iov = &short_iovec[0]; 1391 short_iovec[0].iov_base = (void *)addr; 1392 short_uio.uio_iovcnt = 1; 1393 short_uio.uio_resid = short_iovec[0].iov_len = len; 1394 short_uio.uio_offset = uio_clone->uio_offset; 1395 td->td_ma = ma; 1396 td->td_ma_cnt = cnt; 1397 1398 error = vn_io_fault_doio(args, &short_uio, td); 1399 vm_page_unhold_pages(ma, cnt); 1400 adv = len - short_uio.uio_resid; 1401 1402 uio_clone->uio_iov->iov_base = 1403 (char *)uio_clone->uio_iov->iov_base + adv; 1404 uio_clone->uio_iov->iov_len -= adv; 1405 uio_clone->uio_resid -= adv; 1406 uio_clone->uio_offset += adv; 1407 1408 uio->uio_resid -= adv; 1409 uio->uio_offset += adv; 1410 1411 if (error != 0 || adv == 0) 1412 break; 1413 } 1414 td->td_ma = prev_td_ma; 1415 td->td_ma_cnt = prev_td_ma_cnt; 1416 curthread_pflags_restore(saveheld); 1417 out: 1418 free(uio_clone, M_IOV); 1419 return (error); 1420 } 1421 1422 static int 1423 vn_io_fault(struct file *fp, struct uio *uio, struct ucred *active_cred, 1424 int flags, struct thread *td) 1425 { 1426 fo_rdwr_t *doio; 1427 struct vnode *vp; 1428 void *rl_cookie; 1429 struct vn_io_fault_args args; 1430 int error; 1431 1432 doio = uio->uio_rw == UIO_READ ? vn_read : vn_write; 1433 vp = fp->f_vnode; 1434 1435 /* 1436 * The ability to read(2) on a directory has historically been 1437 * allowed for all users, but this can and has been the source of 1438 * at least one security issue in the past. As such, it is now hidden 1439 * away behind a sysctl for those that actually need it to use it, and 1440 * restricted to root when it's turned on to make it relatively safe to 1441 * leave on for longer sessions of need. 1442 */ 1443 if (vp->v_type == VDIR) { 1444 KASSERT(uio->uio_rw == UIO_READ, 1445 ("illegal write attempted on a directory")); 1446 if (!vfs_allow_read_dir) 1447 return (EISDIR); 1448 if ((error = priv_check(td, PRIV_VFS_READ_DIR)) != 0) 1449 return (EISDIR); 1450 } 1451 1452 foffset_lock_uio(fp, uio, flags); 1453 if (do_vn_io_fault(vp, uio)) { 1454 args.kind = VN_IO_FAULT_FOP; 1455 args.args.fop_args.fp = fp; 1456 args.args.fop_args.doio = doio; 1457 args.cred = active_cred; 1458 args.flags = flags | FOF_OFFSET; 1459 if (uio->uio_rw == UIO_READ) { 1460 rl_cookie = vn_rangelock_rlock(vp, uio->uio_offset, 1461 uio->uio_offset + uio->uio_resid); 1462 } else if ((fp->f_flag & O_APPEND) != 0 || 1463 (flags & FOF_OFFSET) == 0) { 1464 /* For appenders, punt and lock the whole range. */ 1465 rl_cookie = vn_rangelock_wlock(vp, 0, OFF_MAX); 1466 } else { 1467 rl_cookie = vn_rangelock_wlock(vp, uio->uio_offset, 1468 uio->uio_offset + uio->uio_resid); 1469 } 1470 error = vn_io_fault1(vp, uio, &args, td); 1471 vn_rangelock_unlock(vp, rl_cookie); 1472 } else { 1473 error = doio(fp, uio, active_cred, flags | FOF_OFFSET, td); 1474 } 1475 foffset_unlock_uio(fp, uio, flags); 1476 return (error); 1477 } 1478 1479 /* 1480 * Helper function to perform the requested uiomove operation using 1481 * the held pages for io->uio_iov[0].iov_base buffer instead of 1482 * copyin/copyout. Access to the pages with uiomove_fromphys() 1483 * instead of iov_base prevents page faults that could occur due to 1484 * pmap_collect() invalidating the mapping created by 1485 * vm_fault_quick_hold_pages(), or pageout daemon, page laundry or 1486 * object cleanup revoking the write access from page mappings. 1487 * 1488 * Filesystems specified MNTK_NO_IOPF shall use vn_io_fault_uiomove() 1489 * instead of plain uiomove(). 1490 */ 1491 int 1492 vn_io_fault_uiomove(char *data, int xfersize, struct uio *uio) 1493 { 1494 struct uio transp_uio; 1495 struct iovec transp_iov[1]; 1496 struct thread *td; 1497 size_t adv; 1498 int error, pgadv; 1499 1500 td = curthread; 1501 if ((td->td_pflags & TDP_UIOHELD) == 0 || 1502 uio->uio_segflg != UIO_USERSPACE) 1503 return (uiomove(data, xfersize, uio)); 1504 1505 KASSERT(uio->uio_iovcnt == 1, ("uio_iovcnt %d", uio->uio_iovcnt)); 1506 transp_iov[0].iov_base = data; 1507 transp_uio.uio_iov = &transp_iov[0]; 1508 transp_uio.uio_iovcnt = 1; 1509 if (xfersize > uio->uio_resid) 1510 xfersize = uio->uio_resid; 1511 transp_uio.uio_resid = transp_iov[0].iov_len = xfersize; 1512 transp_uio.uio_offset = 0; 1513 transp_uio.uio_segflg = UIO_SYSSPACE; 1514 /* 1515 * Since transp_iov points to data, and td_ma page array 1516 * corresponds to original uio->uio_iov, we need to invert the 1517 * direction of the i/o operation as passed to 1518 * uiomove_fromphys(). 1519 */ 1520 switch (uio->uio_rw) { 1521 case UIO_WRITE: 1522 transp_uio.uio_rw = UIO_READ; 1523 break; 1524 case UIO_READ: 1525 transp_uio.uio_rw = UIO_WRITE; 1526 break; 1527 } 1528 transp_uio.uio_td = uio->uio_td; 1529 error = uiomove_fromphys(td->td_ma, 1530 ((vm_offset_t)uio->uio_iov->iov_base) & PAGE_MASK, 1531 xfersize, &transp_uio); 1532 adv = xfersize - transp_uio.uio_resid; 1533 pgadv = 1534 (((vm_offset_t)uio->uio_iov->iov_base + adv) >> PAGE_SHIFT) - 1535 (((vm_offset_t)uio->uio_iov->iov_base) >> PAGE_SHIFT); 1536 td->td_ma += pgadv; 1537 KASSERT(td->td_ma_cnt >= pgadv, ("consumed pages %d %d", td->td_ma_cnt, 1538 pgadv)); 1539 td->td_ma_cnt -= pgadv; 1540 uio->uio_iov->iov_base = (char *)uio->uio_iov->iov_base + adv; 1541 uio->uio_iov->iov_len -= adv; 1542 uio->uio_resid -= adv; 1543 uio->uio_offset += adv; 1544 return (error); 1545 } 1546 1547 int 1548 vn_io_fault_pgmove(vm_page_t ma[], vm_offset_t offset, int xfersize, 1549 struct uio *uio) 1550 { 1551 struct thread *td; 1552 vm_offset_t iov_base; 1553 int cnt, pgadv; 1554 1555 td = curthread; 1556 if ((td->td_pflags & TDP_UIOHELD) == 0 || 1557 uio->uio_segflg != UIO_USERSPACE) 1558 return (uiomove_fromphys(ma, offset, xfersize, uio)); 1559 1560 KASSERT(uio->uio_iovcnt == 1, ("uio_iovcnt %d", uio->uio_iovcnt)); 1561 cnt = xfersize > uio->uio_resid ? uio->uio_resid : xfersize; 1562 iov_base = (vm_offset_t)uio->uio_iov->iov_base; 1563 switch (uio->uio_rw) { 1564 case UIO_WRITE: 1565 pmap_copy_pages(td->td_ma, iov_base & PAGE_MASK, ma, 1566 offset, cnt); 1567 break; 1568 case UIO_READ: 1569 pmap_copy_pages(ma, offset, td->td_ma, iov_base & PAGE_MASK, 1570 cnt); 1571 break; 1572 } 1573 pgadv = ((iov_base + cnt) >> PAGE_SHIFT) - (iov_base >> PAGE_SHIFT); 1574 td->td_ma += pgadv; 1575 KASSERT(td->td_ma_cnt >= pgadv, ("consumed pages %d %d", td->td_ma_cnt, 1576 pgadv)); 1577 td->td_ma_cnt -= pgadv; 1578 uio->uio_iov->iov_base = (char *)(iov_base + cnt); 1579 uio->uio_iov->iov_len -= cnt; 1580 uio->uio_resid -= cnt; 1581 uio->uio_offset += cnt; 1582 return (0); 1583 } 1584 1585 /* 1586 * File table truncate routine. 1587 */ 1588 static int 1589 vn_truncate(struct file *fp, off_t length, struct ucred *active_cred, 1590 struct thread *td) 1591 { 1592 struct mount *mp; 1593 struct vnode *vp; 1594 void *rl_cookie; 1595 int error; 1596 1597 vp = fp->f_vnode; 1598 1599 retry: 1600 /* 1601 * Lock the whole range for truncation. Otherwise split i/o 1602 * might happen partly before and partly after the truncation. 1603 */ 1604 rl_cookie = vn_rangelock_wlock(vp, 0, OFF_MAX); 1605 error = vn_start_write(vp, &mp, V_WAIT | PCATCH); 1606 if (error) 1607 goto out1; 1608 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 1609 AUDIT_ARG_VNODE1(vp); 1610 if (vp->v_type == VDIR) { 1611 error = EISDIR; 1612 goto out; 1613 } 1614 #ifdef MAC 1615 error = mac_vnode_check_write(active_cred, fp->f_cred, vp); 1616 if (error) 1617 goto out; 1618 #endif 1619 error = vn_truncate_locked(vp, length, (fp->f_flag & O_FSYNC) != 0, 1620 fp->f_cred); 1621 out: 1622 VOP_UNLOCK(vp); 1623 vn_finished_write(mp); 1624 out1: 1625 vn_rangelock_unlock(vp, rl_cookie); 1626 if (error == ERELOOKUP) 1627 goto retry; 1628 return (error); 1629 } 1630 1631 /* 1632 * Truncate a file that is already locked. 1633 */ 1634 int 1635 vn_truncate_locked(struct vnode *vp, off_t length, bool sync, 1636 struct ucred *cred) 1637 { 1638 struct vattr vattr; 1639 int error; 1640 1641 error = VOP_ADD_WRITECOUNT(vp, 1); 1642 if (error == 0) { 1643 VATTR_NULL(&vattr); 1644 vattr.va_size = length; 1645 if (sync) 1646 vattr.va_vaflags |= VA_SYNC; 1647 error = VOP_SETATTR(vp, &vattr, cred); 1648 VOP_ADD_WRITECOUNT_CHECKED(vp, -1); 1649 } 1650 return (error); 1651 } 1652 1653 /* 1654 * File table vnode stat routine. 1655 */ 1656 int 1657 vn_statfile(struct file *fp, struct stat *sb, struct ucred *active_cred, 1658 struct thread *td) 1659 { 1660 struct vnode *vp = fp->f_vnode; 1661 int error; 1662 1663 vn_lock(vp, LK_SHARED | LK_RETRY); 1664 error = VOP_STAT(vp, sb, active_cred, fp->f_cred, td); 1665 VOP_UNLOCK(vp); 1666 1667 return (error); 1668 } 1669 1670 /* 1671 * File table vnode ioctl routine. 1672 */ 1673 static int 1674 vn_ioctl(struct file *fp, u_long com, void *data, struct ucred *active_cred, 1675 struct thread *td) 1676 { 1677 struct vattr vattr; 1678 struct vnode *vp; 1679 struct fiobmap2_arg *bmarg; 1680 int error; 1681 1682 vp = fp->f_vnode; 1683 switch (vp->v_type) { 1684 case VDIR: 1685 case VREG: 1686 switch (com) { 1687 case FIONREAD: 1688 vn_lock(vp, LK_SHARED | LK_RETRY); 1689 error = VOP_GETATTR(vp, &vattr, active_cred); 1690 VOP_UNLOCK(vp); 1691 if (error == 0) 1692 *(int *)data = vattr.va_size - fp->f_offset; 1693 return (error); 1694 case FIOBMAP2: 1695 bmarg = (struct fiobmap2_arg *)data; 1696 vn_lock(vp, LK_SHARED | LK_RETRY); 1697 #ifdef MAC 1698 error = mac_vnode_check_read(active_cred, fp->f_cred, 1699 vp); 1700 if (error == 0) 1701 #endif 1702 error = VOP_BMAP(vp, bmarg->bn, NULL, 1703 &bmarg->bn, &bmarg->runp, &bmarg->runb); 1704 VOP_UNLOCK(vp); 1705 return (error); 1706 case FIONBIO: 1707 case FIOASYNC: 1708 return (0); 1709 default: 1710 return (VOP_IOCTL(vp, com, data, fp->f_flag, 1711 active_cred, td)); 1712 } 1713 break; 1714 case VCHR: 1715 return (VOP_IOCTL(vp, com, data, fp->f_flag, 1716 active_cred, td)); 1717 default: 1718 return (ENOTTY); 1719 } 1720 } 1721 1722 /* 1723 * File table vnode poll routine. 1724 */ 1725 static int 1726 vn_poll(struct file *fp, int events, struct ucred *active_cred, 1727 struct thread *td) 1728 { 1729 struct vnode *vp; 1730 int error; 1731 1732 vp = fp->f_vnode; 1733 #if defined(MAC) || defined(AUDIT) 1734 if (AUDITING_TD(td) || mac_vnode_check_poll_enabled()) { 1735 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 1736 AUDIT_ARG_VNODE1(vp); 1737 error = mac_vnode_check_poll(active_cred, fp->f_cred, vp); 1738 VOP_UNLOCK(vp); 1739 if (error != 0) 1740 return (error); 1741 } 1742 #endif 1743 error = VOP_POLL(vp, events, fp->f_cred, td); 1744 return (error); 1745 } 1746 1747 /* 1748 * Acquire the requested lock and then check for validity. LK_RETRY 1749 * permits vn_lock to return doomed vnodes. 1750 */ 1751 static int __noinline 1752 _vn_lock_fallback(struct vnode *vp, int flags, const char *file, int line, 1753 int error) 1754 { 1755 1756 KASSERT((flags & LK_RETRY) == 0 || error == 0, 1757 ("vn_lock: error %d incompatible with flags %#x", error, flags)); 1758 1759 if (error == 0) 1760 VNASSERT(VN_IS_DOOMED(vp), vp, ("vnode not doomed")); 1761 1762 if ((flags & LK_RETRY) == 0) { 1763 if (error == 0) { 1764 VOP_UNLOCK(vp); 1765 error = ENOENT; 1766 } 1767 return (error); 1768 } 1769 1770 /* 1771 * LK_RETRY case. 1772 * 1773 * Nothing to do if we got the lock. 1774 */ 1775 if (error == 0) 1776 return (0); 1777 1778 /* 1779 * Interlock was dropped by the call in _vn_lock. 1780 */ 1781 flags &= ~LK_INTERLOCK; 1782 do { 1783 error = VOP_LOCK1(vp, flags, file, line); 1784 } while (error != 0); 1785 return (0); 1786 } 1787 1788 int 1789 _vn_lock(struct vnode *vp, int flags, const char *file, int line) 1790 { 1791 int error; 1792 1793 VNASSERT((flags & LK_TYPE_MASK) != 0, vp, 1794 ("vn_lock: no locktype (%d passed)", flags)); 1795 VNPASS(vp->v_holdcnt > 0, vp); 1796 error = VOP_LOCK1(vp, flags, file, line); 1797 if (__predict_false(error != 0 || VN_IS_DOOMED(vp))) 1798 return (_vn_lock_fallback(vp, flags, file, line, error)); 1799 return (0); 1800 } 1801 1802 /* 1803 * File table vnode close routine. 1804 */ 1805 static int 1806 vn_closefile(struct file *fp, struct thread *td) 1807 { 1808 struct vnode *vp; 1809 struct flock lf; 1810 int error; 1811 bool ref; 1812 1813 vp = fp->f_vnode; 1814 fp->f_ops = &badfileops; 1815 ref = (fp->f_flag & FHASLOCK) != 0 && fp->f_type == DTYPE_VNODE; 1816 1817 error = vn_close1(vp, fp->f_flag, fp->f_cred, td, ref); 1818 1819 if (__predict_false(ref)) { 1820 lf.l_whence = SEEK_SET; 1821 lf.l_start = 0; 1822 lf.l_len = 0; 1823 lf.l_type = F_UNLCK; 1824 (void) VOP_ADVLOCK(vp, fp, F_UNLCK, &lf, F_FLOCK); 1825 vrele(vp); 1826 } 1827 return (error); 1828 } 1829 1830 /* 1831 * Preparing to start a filesystem write operation. If the operation is 1832 * permitted, then we bump the count of operations in progress and 1833 * proceed. If a suspend request is in progress, we wait until the 1834 * suspension is over, and then proceed. 1835 */ 1836 static int 1837 vn_start_write_refed(struct mount *mp, int flags, bool mplocked) 1838 { 1839 struct mount_pcpu *mpcpu; 1840 int error, mflags; 1841 1842 if (__predict_true(!mplocked) && (flags & V_XSLEEP) == 0 && 1843 vfs_op_thread_enter(mp, mpcpu)) { 1844 MPASS((mp->mnt_kern_flag & MNTK_SUSPEND) == 0); 1845 vfs_mp_count_add_pcpu(mpcpu, writeopcount, 1); 1846 vfs_op_thread_exit(mp, mpcpu); 1847 return (0); 1848 } 1849 1850 if (mplocked) 1851 mtx_assert(MNT_MTX(mp), MA_OWNED); 1852 else 1853 MNT_ILOCK(mp); 1854 1855 error = 0; 1856 1857 /* 1858 * Check on status of suspension. 1859 */ 1860 if ((curthread->td_pflags & TDP_IGNSUSP) == 0 || 1861 mp->mnt_susp_owner != curthread) { 1862 mflags = ((mp->mnt_vfc->vfc_flags & VFCF_SBDRY) != 0 ? 1863 (flags & PCATCH) : 0) | (PUSER - 1); 1864 while ((mp->mnt_kern_flag & MNTK_SUSPEND) != 0) { 1865 if (flags & V_NOWAIT) { 1866 error = EWOULDBLOCK; 1867 goto unlock; 1868 } 1869 error = msleep(&mp->mnt_flag, MNT_MTX(mp), mflags, 1870 "suspfs", 0); 1871 if (error) 1872 goto unlock; 1873 } 1874 } 1875 if (flags & V_XSLEEP) 1876 goto unlock; 1877 mp->mnt_writeopcount++; 1878 unlock: 1879 if (error != 0 || (flags & V_XSLEEP) != 0) 1880 MNT_REL(mp); 1881 MNT_IUNLOCK(mp); 1882 return (error); 1883 } 1884 1885 int 1886 vn_start_write(struct vnode *vp, struct mount **mpp, int flags) 1887 { 1888 struct mount *mp; 1889 int error; 1890 1891 KASSERT((flags & V_MNTREF) == 0 || (*mpp != NULL && vp == NULL), 1892 ("V_MNTREF requires mp")); 1893 1894 error = 0; 1895 /* 1896 * If a vnode is provided, get and return the mount point that 1897 * to which it will write. 1898 */ 1899 if (vp != NULL) { 1900 if ((error = VOP_GETWRITEMOUNT(vp, mpp)) != 0) { 1901 *mpp = NULL; 1902 if (error != EOPNOTSUPP) 1903 return (error); 1904 return (0); 1905 } 1906 } 1907 if ((mp = *mpp) == NULL) 1908 return (0); 1909 1910 /* 1911 * VOP_GETWRITEMOUNT() returns with the mp refcount held through 1912 * a vfs_ref(). 1913 * As long as a vnode is not provided we need to acquire a 1914 * refcount for the provided mountpoint too, in order to 1915 * emulate a vfs_ref(). 1916 */ 1917 if (vp == NULL && (flags & V_MNTREF) == 0) 1918 vfs_ref(mp); 1919 1920 return (vn_start_write_refed(mp, flags, false)); 1921 } 1922 1923 /* 1924 * Secondary suspension. Used by operations such as vop_inactive 1925 * routines that are needed by the higher level functions. These 1926 * are allowed to proceed until all the higher level functions have 1927 * completed (indicated by mnt_writeopcount dropping to zero). At that 1928 * time, these operations are halted until the suspension is over. 1929 */ 1930 int 1931 vn_start_secondary_write(struct vnode *vp, struct mount **mpp, int flags) 1932 { 1933 struct mount *mp; 1934 int error; 1935 1936 KASSERT((flags & V_MNTREF) == 0 || (*mpp != NULL && vp == NULL), 1937 ("V_MNTREF requires mp")); 1938 1939 retry: 1940 if (vp != NULL) { 1941 if ((error = VOP_GETWRITEMOUNT(vp, mpp)) != 0) { 1942 *mpp = NULL; 1943 if (error != EOPNOTSUPP) 1944 return (error); 1945 return (0); 1946 } 1947 } 1948 /* 1949 * If we are not suspended or have not yet reached suspended 1950 * mode, then let the operation proceed. 1951 */ 1952 if ((mp = *mpp) == NULL) 1953 return (0); 1954 1955 /* 1956 * VOP_GETWRITEMOUNT() returns with the mp refcount held through 1957 * a vfs_ref(). 1958 * As long as a vnode is not provided we need to acquire a 1959 * refcount for the provided mountpoint too, in order to 1960 * emulate a vfs_ref(). 1961 */ 1962 MNT_ILOCK(mp); 1963 if (vp == NULL && (flags & V_MNTREF) == 0) 1964 MNT_REF(mp); 1965 if ((mp->mnt_kern_flag & (MNTK_SUSPENDED | MNTK_SUSPEND2)) == 0) { 1966 mp->mnt_secondary_writes++; 1967 mp->mnt_secondary_accwrites++; 1968 MNT_IUNLOCK(mp); 1969 return (0); 1970 } 1971 if (flags & V_NOWAIT) { 1972 MNT_REL(mp); 1973 MNT_IUNLOCK(mp); 1974 return (EWOULDBLOCK); 1975 } 1976 /* 1977 * Wait for the suspension to finish. 1978 */ 1979 error = msleep(&mp->mnt_flag, MNT_MTX(mp), (PUSER - 1) | PDROP | 1980 ((mp->mnt_vfc->vfc_flags & VFCF_SBDRY) != 0 ? (flags & PCATCH) : 0), 1981 "suspfs", 0); 1982 vfs_rel(mp); 1983 if (error == 0) 1984 goto retry; 1985 return (error); 1986 } 1987 1988 /* 1989 * Filesystem write operation has completed. If we are suspending and this 1990 * operation is the last one, notify the suspender that the suspension is 1991 * now in effect. 1992 */ 1993 void 1994 vn_finished_write(struct mount *mp) 1995 { 1996 struct mount_pcpu *mpcpu; 1997 int c; 1998 1999 if (mp == NULL) 2000 return; 2001 2002 if (vfs_op_thread_enter(mp, mpcpu)) { 2003 vfs_mp_count_sub_pcpu(mpcpu, writeopcount, 1); 2004 vfs_mp_count_sub_pcpu(mpcpu, ref, 1); 2005 vfs_op_thread_exit(mp, mpcpu); 2006 return; 2007 } 2008 2009 MNT_ILOCK(mp); 2010 vfs_assert_mount_counters(mp); 2011 MNT_REL(mp); 2012 c = --mp->mnt_writeopcount; 2013 if (mp->mnt_vfs_ops == 0) { 2014 MPASS((mp->mnt_kern_flag & MNTK_SUSPEND) == 0); 2015 MNT_IUNLOCK(mp); 2016 return; 2017 } 2018 if (c < 0) 2019 vfs_dump_mount_counters(mp); 2020 if ((mp->mnt_kern_flag & MNTK_SUSPEND) != 0 && c == 0) 2021 wakeup(&mp->mnt_writeopcount); 2022 MNT_IUNLOCK(mp); 2023 } 2024 2025 /* 2026 * Filesystem secondary write operation has completed. If we are 2027 * suspending and this operation is the last one, notify the suspender 2028 * that the suspension is now in effect. 2029 */ 2030 void 2031 vn_finished_secondary_write(struct mount *mp) 2032 { 2033 if (mp == NULL) 2034 return; 2035 MNT_ILOCK(mp); 2036 MNT_REL(mp); 2037 mp->mnt_secondary_writes--; 2038 if (mp->mnt_secondary_writes < 0) 2039 panic("vn_finished_secondary_write: neg cnt"); 2040 if ((mp->mnt_kern_flag & MNTK_SUSPEND) != 0 && 2041 mp->mnt_secondary_writes <= 0) 2042 wakeup(&mp->mnt_secondary_writes); 2043 MNT_IUNLOCK(mp); 2044 } 2045 2046 /* 2047 * Request a filesystem to suspend write operations. 2048 */ 2049 int 2050 vfs_write_suspend(struct mount *mp, int flags) 2051 { 2052 int error; 2053 2054 vfs_op_enter(mp); 2055 2056 MNT_ILOCK(mp); 2057 vfs_assert_mount_counters(mp); 2058 if (mp->mnt_susp_owner == curthread) { 2059 vfs_op_exit_locked(mp); 2060 MNT_IUNLOCK(mp); 2061 return (EALREADY); 2062 } 2063 while (mp->mnt_kern_flag & MNTK_SUSPEND) 2064 msleep(&mp->mnt_flag, MNT_MTX(mp), PUSER - 1, "wsuspfs", 0); 2065 2066 /* 2067 * Unmount holds a write reference on the mount point. If we 2068 * own busy reference and drain for writers, we deadlock with 2069 * the reference draining in the unmount path. Callers of 2070 * vfs_write_suspend() must specify VS_SKIP_UNMOUNT if 2071 * vfs_busy() reference is owned and caller is not in the 2072 * unmount context. 2073 */ 2074 if ((flags & VS_SKIP_UNMOUNT) != 0 && 2075 (mp->mnt_kern_flag & MNTK_UNMOUNT) != 0) { 2076 vfs_op_exit_locked(mp); 2077 MNT_IUNLOCK(mp); 2078 return (EBUSY); 2079 } 2080 2081 mp->mnt_kern_flag |= MNTK_SUSPEND; 2082 mp->mnt_susp_owner = curthread; 2083 if (mp->mnt_writeopcount > 0) 2084 (void) msleep(&mp->mnt_writeopcount, 2085 MNT_MTX(mp), (PUSER - 1)|PDROP, "suspwt", 0); 2086 else 2087 MNT_IUNLOCK(mp); 2088 if ((error = VFS_SYNC(mp, MNT_SUSPEND)) != 0) { 2089 vfs_write_resume(mp, 0); 2090 /* vfs_write_resume does vfs_op_exit() for us */ 2091 } 2092 return (error); 2093 } 2094 2095 /* 2096 * Request a filesystem to resume write operations. 2097 */ 2098 void 2099 vfs_write_resume(struct mount *mp, int flags) 2100 { 2101 2102 MNT_ILOCK(mp); 2103 if ((mp->mnt_kern_flag & MNTK_SUSPEND) != 0) { 2104 KASSERT(mp->mnt_susp_owner == curthread, ("mnt_susp_owner")); 2105 mp->mnt_kern_flag &= ~(MNTK_SUSPEND | MNTK_SUSPEND2 | 2106 MNTK_SUSPENDED); 2107 mp->mnt_susp_owner = NULL; 2108 wakeup(&mp->mnt_writeopcount); 2109 wakeup(&mp->mnt_flag); 2110 curthread->td_pflags &= ~TDP_IGNSUSP; 2111 if ((flags & VR_START_WRITE) != 0) { 2112 MNT_REF(mp); 2113 mp->mnt_writeopcount++; 2114 } 2115 MNT_IUNLOCK(mp); 2116 if ((flags & VR_NO_SUSPCLR) == 0) 2117 VFS_SUSP_CLEAN(mp); 2118 vfs_op_exit(mp); 2119 } else if ((flags & VR_START_WRITE) != 0) { 2120 MNT_REF(mp); 2121 vn_start_write_refed(mp, 0, true); 2122 } else { 2123 MNT_IUNLOCK(mp); 2124 } 2125 } 2126 2127 /* 2128 * Helper loop around vfs_write_suspend() for filesystem unmount VFS 2129 * methods. 2130 */ 2131 int 2132 vfs_write_suspend_umnt(struct mount *mp) 2133 { 2134 int error; 2135 2136 KASSERT((curthread->td_pflags & TDP_IGNSUSP) == 0, 2137 ("vfs_write_suspend_umnt: recursed")); 2138 2139 /* dounmount() already called vn_start_write(). */ 2140 for (;;) { 2141 vn_finished_write(mp); 2142 error = vfs_write_suspend(mp, 0); 2143 if (error != 0) { 2144 vn_start_write(NULL, &mp, V_WAIT); 2145 return (error); 2146 } 2147 MNT_ILOCK(mp); 2148 if ((mp->mnt_kern_flag & MNTK_SUSPENDED) != 0) 2149 break; 2150 MNT_IUNLOCK(mp); 2151 vn_start_write(NULL, &mp, V_WAIT); 2152 } 2153 mp->mnt_kern_flag &= ~(MNTK_SUSPENDED | MNTK_SUSPEND2); 2154 wakeup(&mp->mnt_flag); 2155 MNT_IUNLOCK(mp); 2156 curthread->td_pflags |= TDP_IGNSUSP; 2157 return (0); 2158 } 2159 2160 /* 2161 * Implement kqueues for files by translating it to vnode operation. 2162 */ 2163 static int 2164 vn_kqfilter(struct file *fp, struct knote *kn) 2165 { 2166 2167 return (VOP_KQFILTER(fp->f_vnode, kn)); 2168 } 2169 2170 int 2171 vn_kqfilter_opath(struct file *fp, struct knote *kn) 2172 { 2173 if ((fp->f_flag & FKQALLOWED) == 0) 2174 return (EBADF); 2175 return (vn_kqfilter(fp, kn)); 2176 } 2177 2178 /* 2179 * Simplified in-kernel wrapper calls for extended attribute access. 2180 * Both calls pass in a NULL credential, authorizing as "kernel" access. 2181 * Set IO_NODELOCKED in ioflg if the vnode is already locked. 2182 */ 2183 int 2184 vn_extattr_get(struct vnode *vp, int ioflg, int attrnamespace, 2185 const char *attrname, int *buflen, char *buf, struct thread *td) 2186 { 2187 struct uio auio; 2188 struct iovec iov; 2189 int error; 2190 2191 iov.iov_len = *buflen; 2192 iov.iov_base = buf; 2193 2194 auio.uio_iov = &iov; 2195 auio.uio_iovcnt = 1; 2196 auio.uio_rw = UIO_READ; 2197 auio.uio_segflg = UIO_SYSSPACE; 2198 auio.uio_td = td; 2199 auio.uio_offset = 0; 2200 auio.uio_resid = *buflen; 2201 2202 if ((ioflg & IO_NODELOCKED) == 0) 2203 vn_lock(vp, LK_SHARED | LK_RETRY); 2204 2205 ASSERT_VOP_LOCKED(vp, "IO_NODELOCKED with no vp lock held"); 2206 2207 /* authorize attribute retrieval as kernel */ 2208 error = VOP_GETEXTATTR(vp, attrnamespace, attrname, &auio, NULL, NULL, 2209 td); 2210 2211 if ((ioflg & IO_NODELOCKED) == 0) 2212 VOP_UNLOCK(vp); 2213 2214 if (error == 0) { 2215 *buflen = *buflen - auio.uio_resid; 2216 } 2217 2218 return (error); 2219 } 2220 2221 /* 2222 * XXX failure mode if partially written? 2223 */ 2224 int 2225 vn_extattr_set(struct vnode *vp, int ioflg, int attrnamespace, 2226 const char *attrname, int buflen, char *buf, struct thread *td) 2227 { 2228 struct uio auio; 2229 struct iovec iov; 2230 struct mount *mp; 2231 int error; 2232 2233 iov.iov_len = buflen; 2234 iov.iov_base = buf; 2235 2236 auio.uio_iov = &iov; 2237 auio.uio_iovcnt = 1; 2238 auio.uio_rw = UIO_WRITE; 2239 auio.uio_segflg = UIO_SYSSPACE; 2240 auio.uio_td = td; 2241 auio.uio_offset = 0; 2242 auio.uio_resid = buflen; 2243 2244 if ((ioflg & IO_NODELOCKED) == 0) { 2245 if ((error = vn_start_write(vp, &mp, V_WAIT)) != 0) 2246 return (error); 2247 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 2248 } 2249 2250 ASSERT_VOP_LOCKED(vp, "IO_NODELOCKED with no vp lock held"); 2251 2252 /* authorize attribute setting as kernel */ 2253 error = VOP_SETEXTATTR(vp, attrnamespace, attrname, &auio, NULL, td); 2254 2255 if ((ioflg & IO_NODELOCKED) == 0) { 2256 vn_finished_write(mp); 2257 VOP_UNLOCK(vp); 2258 } 2259 2260 return (error); 2261 } 2262 2263 int 2264 vn_extattr_rm(struct vnode *vp, int ioflg, int attrnamespace, 2265 const char *attrname, struct thread *td) 2266 { 2267 struct mount *mp; 2268 int error; 2269 2270 if ((ioflg & IO_NODELOCKED) == 0) { 2271 if ((error = vn_start_write(vp, &mp, V_WAIT)) != 0) 2272 return (error); 2273 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 2274 } 2275 2276 ASSERT_VOP_LOCKED(vp, "IO_NODELOCKED with no vp lock held"); 2277 2278 /* authorize attribute removal as kernel */ 2279 error = VOP_DELETEEXTATTR(vp, attrnamespace, attrname, NULL, td); 2280 if (error == EOPNOTSUPP) 2281 error = VOP_SETEXTATTR(vp, attrnamespace, attrname, NULL, 2282 NULL, td); 2283 2284 if ((ioflg & IO_NODELOCKED) == 0) { 2285 vn_finished_write(mp); 2286 VOP_UNLOCK(vp); 2287 } 2288 2289 return (error); 2290 } 2291 2292 static int 2293 vn_get_ino_alloc_vget(struct mount *mp, void *arg, int lkflags, 2294 struct vnode **rvp) 2295 { 2296 2297 return (VFS_VGET(mp, *(ino_t *)arg, lkflags, rvp)); 2298 } 2299 2300 int 2301 vn_vget_ino(struct vnode *vp, ino_t ino, int lkflags, struct vnode **rvp) 2302 { 2303 2304 return (vn_vget_ino_gen(vp, vn_get_ino_alloc_vget, &ino, 2305 lkflags, rvp)); 2306 } 2307 2308 int 2309 vn_vget_ino_gen(struct vnode *vp, vn_get_ino_t alloc, void *alloc_arg, 2310 int lkflags, struct vnode **rvp) 2311 { 2312 struct mount *mp; 2313 int ltype, error; 2314 2315 ASSERT_VOP_LOCKED(vp, "vn_vget_ino_get"); 2316 mp = vp->v_mount; 2317 ltype = VOP_ISLOCKED(vp); 2318 KASSERT(ltype == LK_EXCLUSIVE || ltype == LK_SHARED, 2319 ("vn_vget_ino: vp not locked")); 2320 error = vfs_busy(mp, MBF_NOWAIT); 2321 if (error != 0) { 2322 vfs_ref(mp); 2323 VOP_UNLOCK(vp); 2324 error = vfs_busy(mp, 0); 2325 vn_lock(vp, ltype | LK_RETRY); 2326 vfs_rel(mp); 2327 if (error != 0) 2328 return (ENOENT); 2329 if (VN_IS_DOOMED(vp)) { 2330 vfs_unbusy(mp); 2331 return (ENOENT); 2332 } 2333 } 2334 VOP_UNLOCK(vp); 2335 error = alloc(mp, alloc_arg, lkflags, rvp); 2336 vfs_unbusy(mp); 2337 if (error != 0 || *rvp != vp) 2338 vn_lock(vp, ltype | LK_RETRY); 2339 if (VN_IS_DOOMED(vp)) { 2340 if (error == 0) { 2341 if (*rvp == vp) 2342 vunref(vp); 2343 else 2344 vput(*rvp); 2345 } 2346 error = ENOENT; 2347 } 2348 return (error); 2349 } 2350 2351 int 2352 vn_rlimit_fsize(const struct vnode *vp, const struct uio *uio, 2353 struct thread *td) 2354 { 2355 2356 if (vp->v_type != VREG || td == NULL) 2357 return (0); 2358 if ((uoff_t)uio->uio_offset + uio->uio_resid > 2359 lim_cur(td, RLIMIT_FSIZE)) { 2360 PROC_LOCK(td->td_proc); 2361 kern_psignal(td->td_proc, SIGXFSZ); 2362 PROC_UNLOCK(td->td_proc); 2363 return (EFBIG); 2364 } 2365 return (0); 2366 } 2367 2368 int 2369 vn_chmod(struct file *fp, mode_t mode, struct ucred *active_cred, 2370 struct thread *td) 2371 { 2372 struct vnode *vp; 2373 2374 vp = fp->f_vnode; 2375 #ifdef AUDIT 2376 vn_lock(vp, LK_SHARED | LK_RETRY); 2377 AUDIT_ARG_VNODE1(vp); 2378 VOP_UNLOCK(vp); 2379 #endif 2380 return (setfmode(td, active_cred, vp, mode)); 2381 } 2382 2383 int 2384 vn_chown(struct file *fp, uid_t uid, gid_t gid, struct ucred *active_cred, 2385 struct thread *td) 2386 { 2387 struct vnode *vp; 2388 2389 vp = fp->f_vnode; 2390 #ifdef AUDIT 2391 vn_lock(vp, LK_SHARED | LK_RETRY); 2392 AUDIT_ARG_VNODE1(vp); 2393 VOP_UNLOCK(vp); 2394 #endif 2395 return (setfown(td, active_cred, vp, uid, gid)); 2396 } 2397 2398 void 2399 vn_pages_remove(struct vnode *vp, vm_pindex_t start, vm_pindex_t end) 2400 { 2401 vm_object_t object; 2402 2403 if ((object = vp->v_object) == NULL) 2404 return; 2405 VM_OBJECT_WLOCK(object); 2406 vm_object_page_remove(object, start, end, 0); 2407 VM_OBJECT_WUNLOCK(object); 2408 } 2409 2410 int 2411 vn_bmap_seekhole(struct vnode *vp, u_long cmd, off_t *off, struct ucred *cred) 2412 { 2413 struct vattr va; 2414 daddr_t bn, bnp; 2415 uint64_t bsize; 2416 off_t noff; 2417 int error; 2418 2419 KASSERT(cmd == FIOSEEKHOLE || cmd == FIOSEEKDATA, 2420 ("Wrong command %lu", cmd)); 2421 2422 if (vn_lock(vp, LK_SHARED) != 0) 2423 return (EBADF); 2424 if (vp->v_type != VREG) { 2425 error = ENOTTY; 2426 goto unlock; 2427 } 2428 error = VOP_GETATTR(vp, &va, cred); 2429 if (error != 0) 2430 goto unlock; 2431 noff = *off; 2432 if (noff >= va.va_size) { 2433 error = ENXIO; 2434 goto unlock; 2435 } 2436 bsize = vp->v_mount->mnt_stat.f_iosize; 2437 for (bn = noff / bsize; noff < va.va_size; bn++, noff += bsize - 2438 noff % bsize) { 2439 error = VOP_BMAP(vp, bn, NULL, &bnp, NULL, NULL); 2440 if (error == EOPNOTSUPP) { 2441 error = ENOTTY; 2442 goto unlock; 2443 } 2444 if ((bnp == -1 && cmd == FIOSEEKHOLE) || 2445 (bnp != -1 && cmd == FIOSEEKDATA)) { 2446 noff = bn * bsize; 2447 if (noff < *off) 2448 noff = *off; 2449 goto unlock; 2450 } 2451 } 2452 if (noff > va.va_size) 2453 noff = va.va_size; 2454 /* noff == va.va_size. There is an implicit hole at the end of file. */ 2455 if (cmd == FIOSEEKDATA) 2456 error = ENXIO; 2457 unlock: 2458 VOP_UNLOCK(vp); 2459 if (error == 0) 2460 *off = noff; 2461 return (error); 2462 } 2463 2464 int 2465 vn_seek(struct file *fp, off_t offset, int whence, struct thread *td) 2466 { 2467 struct ucred *cred; 2468 struct vnode *vp; 2469 struct vattr vattr; 2470 off_t foffset, size; 2471 int error, noneg; 2472 2473 cred = td->td_ucred; 2474 vp = fp->f_vnode; 2475 foffset = foffset_lock(fp, 0); 2476 noneg = (vp->v_type != VCHR); 2477 error = 0; 2478 switch (whence) { 2479 case L_INCR: 2480 if (noneg && 2481 (foffset < 0 || 2482 (offset > 0 && foffset > OFF_MAX - offset))) { 2483 error = EOVERFLOW; 2484 break; 2485 } 2486 offset += foffset; 2487 break; 2488 case L_XTND: 2489 vn_lock(vp, LK_SHARED | LK_RETRY); 2490 error = VOP_GETATTR(vp, &vattr, cred); 2491 VOP_UNLOCK(vp); 2492 if (error) 2493 break; 2494 2495 /* 2496 * If the file references a disk device, then fetch 2497 * the media size and use that to determine the ending 2498 * offset. 2499 */ 2500 if (vattr.va_size == 0 && vp->v_type == VCHR && 2501 fo_ioctl(fp, DIOCGMEDIASIZE, &size, cred, td) == 0) 2502 vattr.va_size = size; 2503 if (noneg && 2504 (vattr.va_size > OFF_MAX || 2505 (offset > 0 && vattr.va_size > OFF_MAX - offset))) { 2506 error = EOVERFLOW; 2507 break; 2508 } 2509 offset += vattr.va_size; 2510 break; 2511 case L_SET: 2512 break; 2513 case SEEK_DATA: 2514 error = fo_ioctl(fp, FIOSEEKDATA, &offset, cred, td); 2515 if (error == ENOTTY) 2516 error = EINVAL; 2517 break; 2518 case SEEK_HOLE: 2519 error = fo_ioctl(fp, FIOSEEKHOLE, &offset, cred, td); 2520 if (error == ENOTTY) 2521 error = EINVAL; 2522 break; 2523 default: 2524 error = EINVAL; 2525 } 2526 if (error == 0 && noneg && offset < 0) 2527 error = EINVAL; 2528 if (error != 0) 2529 goto drop; 2530 VFS_KNOTE_UNLOCKED(vp, 0); 2531 td->td_uretoff.tdu_off = offset; 2532 drop: 2533 foffset_unlock(fp, offset, error != 0 ? FOF_NOUPDATE : 0); 2534 return (error); 2535 } 2536 2537 int 2538 vn_utimes_perm(struct vnode *vp, struct vattr *vap, struct ucred *cred, 2539 struct thread *td) 2540 { 2541 int error; 2542 2543 /* 2544 * Grant permission if the caller is the owner of the file, or 2545 * the super-user, or has ACL_WRITE_ATTRIBUTES permission on 2546 * on the file. If the time pointer is null, then write 2547 * permission on the file is also sufficient. 2548 * 2549 * From NFSv4.1, draft 21, 6.2.1.3.1, Discussion of Mask Attributes: 2550 * A user having ACL_WRITE_DATA or ACL_WRITE_ATTRIBUTES 2551 * will be allowed to set the times [..] to the current 2552 * server time. 2553 */ 2554 error = VOP_ACCESSX(vp, VWRITE_ATTRIBUTES, cred, td); 2555 if (error != 0 && (vap->va_vaflags & VA_UTIMES_NULL) != 0) 2556 error = VOP_ACCESS(vp, VWRITE, cred, td); 2557 return (error); 2558 } 2559 2560 int 2561 vn_fill_kinfo(struct file *fp, struct kinfo_file *kif, struct filedesc *fdp) 2562 { 2563 struct vnode *vp; 2564 int error; 2565 2566 if (fp->f_type == DTYPE_FIFO) 2567 kif->kf_type = KF_TYPE_FIFO; 2568 else 2569 kif->kf_type = KF_TYPE_VNODE; 2570 vp = fp->f_vnode; 2571 vref(vp); 2572 FILEDESC_SUNLOCK(fdp); 2573 error = vn_fill_kinfo_vnode(vp, kif); 2574 vrele(vp); 2575 FILEDESC_SLOCK(fdp); 2576 return (error); 2577 } 2578 2579 static inline void 2580 vn_fill_junk(struct kinfo_file *kif) 2581 { 2582 size_t len, olen; 2583 2584 /* 2585 * Simulate vn_fullpath returning changing values for a given 2586 * vp during e.g. coredump. 2587 */ 2588 len = (arc4random() % (sizeof(kif->kf_path) - 2)) + 1; 2589 olen = strlen(kif->kf_path); 2590 if (len < olen) 2591 strcpy(&kif->kf_path[len - 1], "$"); 2592 else 2593 for (; olen < len; olen++) 2594 strcpy(&kif->kf_path[olen], "A"); 2595 } 2596 2597 int 2598 vn_fill_kinfo_vnode(struct vnode *vp, struct kinfo_file *kif) 2599 { 2600 struct vattr va; 2601 char *fullpath, *freepath; 2602 int error; 2603 2604 kif->kf_un.kf_file.kf_file_type = vntype_to_kinfo(vp->v_type); 2605 freepath = NULL; 2606 fullpath = "-"; 2607 error = vn_fullpath(vp, &fullpath, &freepath); 2608 if (error == 0) { 2609 strlcpy(kif->kf_path, fullpath, sizeof(kif->kf_path)); 2610 } 2611 if (freepath != NULL) 2612 free(freepath, M_TEMP); 2613 2614 KFAIL_POINT_CODE(DEBUG_FP, fill_kinfo_vnode__random_path, 2615 vn_fill_junk(kif); 2616 ); 2617 2618 /* 2619 * Retrieve vnode attributes. 2620 */ 2621 va.va_fsid = VNOVAL; 2622 va.va_rdev = NODEV; 2623 vn_lock(vp, LK_SHARED | LK_RETRY); 2624 error = VOP_GETATTR(vp, &va, curthread->td_ucred); 2625 VOP_UNLOCK(vp); 2626 if (error != 0) 2627 return (error); 2628 if (va.va_fsid != VNOVAL) 2629 kif->kf_un.kf_file.kf_file_fsid = va.va_fsid; 2630 else 2631 kif->kf_un.kf_file.kf_file_fsid = 2632 vp->v_mount->mnt_stat.f_fsid.val[0]; 2633 kif->kf_un.kf_file.kf_file_fsid_freebsd11 = 2634 kif->kf_un.kf_file.kf_file_fsid; /* truncate */ 2635 kif->kf_un.kf_file.kf_file_fileid = va.va_fileid; 2636 kif->kf_un.kf_file.kf_file_mode = MAKEIMODE(va.va_type, va.va_mode); 2637 kif->kf_un.kf_file.kf_file_size = va.va_size; 2638 kif->kf_un.kf_file.kf_file_rdev = va.va_rdev; 2639 kif->kf_un.kf_file.kf_file_rdev_freebsd11 = 2640 kif->kf_un.kf_file.kf_file_rdev; /* truncate */ 2641 return (0); 2642 } 2643 2644 int 2645 vn_mmap(struct file *fp, vm_map_t map, vm_offset_t *addr, vm_size_t size, 2646 vm_prot_t prot, vm_prot_t cap_maxprot, int flags, vm_ooffset_t foff, 2647 struct thread *td) 2648 { 2649 #ifdef HWPMC_HOOKS 2650 struct pmckern_map_in pkm; 2651 #endif 2652 struct mount *mp; 2653 struct vnode *vp; 2654 vm_object_t object; 2655 vm_prot_t maxprot; 2656 boolean_t writecounted; 2657 int error; 2658 2659 #if defined(COMPAT_FREEBSD7) || defined(COMPAT_FREEBSD6) || \ 2660 defined(COMPAT_FREEBSD5) || defined(COMPAT_FREEBSD4) 2661 /* 2662 * POSIX shared-memory objects are defined to have 2663 * kernel persistence, and are not defined to support 2664 * read(2)/write(2) -- or even open(2). Thus, we can 2665 * use MAP_ASYNC to trade on-disk coherence for speed. 2666 * The shm_open(3) library routine turns on the FPOSIXSHM 2667 * flag to request this behavior. 2668 */ 2669 if ((fp->f_flag & FPOSIXSHM) != 0) 2670 flags |= MAP_NOSYNC; 2671 #endif 2672 vp = fp->f_vnode; 2673 2674 /* 2675 * Ensure that file and memory protections are 2676 * compatible. Note that we only worry about 2677 * writability if mapping is shared; in this case, 2678 * current and max prot are dictated by the open file. 2679 * XXX use the vnode instead? Problem is: what 2680 * credentials do we use for determination? What if 2681 * proc does a setuid? 2682 */ 2683 mp = vp->v_mount; 2684 if (mp != NULL && (mp->mnt_flag & MNT_NOEXEC) != 0) { 2685 maxprot = VM_PROT_NONE; 2686 if ((prot & VM_PROT_EXECUTE) != 0) 2687 return (EACCES); 2688 } else 2689 maxprot = VM_PROT_EXECUTE; 2690 if ((fp->f_flag & FREAD) != 0) 2691 maxprot |= VM_PROT_READ; 2692 else if ((prot & VM_PROT_READ) != 0) 2693 return (EACCES); 2694 2695 /* 2696 * If we are sharing potential changes via MAP_SHARED and we 2697 * are trying to get write permission although we opened it 2698 * without asking for it, bail out. 2699 */ 2700 if ((flags & MAP_SHARED) != 0) { 2701 if ((fp->f_flag & FWRITE) != 0) 2702 maxprot |= VM_PROT_WRITE; 2703 else if ((prot & VM_PROT_WRITE) != 0) 2704 return (EACCES); 2705 } else { 2706 maxprot |= VM_PROT_WRITE; 2707 cap_maxprot |= VM_PROT_WRITE; 2708 } 2709 maxprot &= cap_maxprot; 2710 2711 /* 2712 * For regular files and shared memory, POSIX requires that 2713 * the value of foff be a legitimate offset within the data 2714 * object. In particular, negative offsets are invalid. 2715 * Blocking negative offsets and overflows here avoids 2716 * possible wraparound or user-level access into reserved 2717 * ranges of the data object later. In contrast, POSIX does 2718 * not dictate how offsets are used by device drivers, so in 2719 * the case of a device mapping a negative offset is passed 2720 * on. 2721 */ 2722 if ( 2723 #ifdef _LP64 2724 size > OFF_MAX || 2725 #endif 2726 foff > OFF_MAX - size) 2727 return (EINVAL); 2728 2729 writecounted = FALSE; 2730 error = vm_mmap_vnode(td, size, prot, &maxprot, &flags, vp, 2731 &foff, &object, &writecounted); 2732 if (error != 0) 2733 return (error); 2734 error = vm_mmap_object(map, addr, size, prot, maxprot, flags, object, 2735 foff, writecounted, td); 2736 if (error != 0) { 2737 /* 2738 * If this mapping was accounted for in the vnode's 2739 * writecount, then undo that now. 2740 */ 2741 if (writecounted) 2742 vm_pager_release_writecount(object, 0, size); 2743 vm_object_deallocate(object); 2744 } 2745 #ifdef HWPMC_HOOKS 2746 /* Inform hwpmc(4) if an executable is being mapped. */ 2747 if (PMC_HOOK_INSTALLED(PMC_FN_MMAP)) { 2748 if ((prot & VM_PROT_EXECUTE) != 0 && error == 0) { 2749 pkm.pm_file = vp; 2750 pkm.pm_address = (uintptr_t) *addr; 2751 PMC_CALL_HOOK_UNLOCKED(td, PMC_FN_MMAP, (void *) &pkm); 2752 } 2753 } 2754 #endif 2755 return (error); 2756 } 2757 2758 void 2759 vn_fsid(struct vnode *vp, struct vattr *va) 2760 { 2761 fsid_t *f; 2762 2763 f = &vp->v_mount->mnt_stat.f_fsid; 2764 va->va_fsid = (uint32_t)f->val[1]; 2765 va->va_fsid <<= sizeof(f->val[1]) * NBBY; 2766 va->va_fsid += (uint32_t)f->val[0]; 2767 } 2768 2769 int 2770 vn_fsync_buf(struct vnode *vp, int waitfor) 2771 { 2772 struct buf *bp, *nbp; 2773 struct bufobj *bo; 2774 struct mount *mp; 2775 int error, maxretry; 2776 2777 error = 0; 2778 maxretry = 10000; /* large, arbitrarily chosen */ 2779 mp = NULL; 2780 if (vp->v_type == VCHR) { 2781 VI_LOCK(vp); 2782 mp = vp->v_rdev->si_mountpt; 2783 VI_UNLOCK(vp); 2784 } 2785 bo = &vp->v_bufobj; 2786 BO_LOCK(bo); 2787 loop1: 2788 /* 2789 * MARK/SCAN initialization to avoid infinite loops. 2790 */ 2791 TAILQ_FOREACH(bp, &bo->bo_dirty.bv_hd, b_bobufs) { 2792 bp->b_vflags &= ~BV_SCANNED; 2793 bp->b_error = 0; 2794 } 2795 2796 /* 2797 * Flush all dirty buffers associated with a vnode. 2798 */ 2799 loop2: 2800 TAILQ_FOREACH_SAFE(bp, &bo->bo_dirty.bv_hd, b_bobufs, nbp) { 2801 if ((bp->b_vflags & BV_SCANNED) != 0) 2802 continue; 2803 bp->b_vflags |= BV_SCANNED; 2804 if (BUF_LOCK(bp, LK_EXCLUSIVE | LK_NOWAIT, NULL)) { 2805 if (waitfor != MNT_WAIT) 2806 continue; 2807 if (BUF_LOCK(bp, 2808 LK_EXCLUSIVE | LK_INTERLOCK | LK_SLEEPFAIL, 2809 BO_LOCKPTR(bo)) != 0) { 2810 BO_LOCK(bo); 2811 goto loop1; 2812 } 2813 BO_LOCK(bo); 2814 } 2815 BO_UNLOCK(bo); 2816 KASSERT(bp->b_bufobj == bo, 2817 ("bp %p wrong b_bufobj %p should be %p", 2818 bp, bp->b_bufobj, bo)); 2819 if ((bp->b_flags & B_DELWRI) == 0) 2820 panic("fsync: not dirty"); 2821 if ((vp->v_object != NULL) && (bp->b_flags & B_CLUSTEROK)) { 2822 vfs_bio_awrite(bp); 2823 } else { 2824 bremfree(bp); 2825 bawrite(bp); 2826 } 2827 if (maxretry < 1000) 2828 pause("dirty", hz < 1000 ? 1 : hz / 1000); 2829 BO_LOCK(bo); 2830 goto loop2; 2831 } 2832 2833 /* 2834 * If synchronous the caller expects us to completely resolve all 2835 * dirty buffers in the system. Wait for in-progress I/O to 2836 * complete (which could include background bitmap writes), then 2837 * retry if dirty blocks still exist. 2838 */ 2839 if (waitfor == MNT_WAIT) { 2840 bufobj_wwait(bo, 0, 0); 2841 if (bo->bo_dirty.bv_cnt > 0) { 2842 /* 2843 * If we are unable to write any of these buffers 2844 * then we fail now rather than trying endlessly 2845 * to write them out. 2846 */ 2847 TAILQ_FOREACH(bp, &bo->bo_dirty.bv_hd, b_bobufs) 2848 if ((error = bp->b_error) != 0) 2849 break; 2850 if ((mp != NULL && mp->mnt_secondary_writes > 0) || 2851 (error == 0 && --maxretry >= 0)) 2852 goto loop1; 2853 if (error == 0) 2854 error = EAGAIN; 2855 } 2856 } 2857 BO_UNLOCK(bo); 2858 if (error != 0) 2859 vn_printf(vp, "fsync: giving up on dirty (error = %d) ", error); 2860 2861 return (error); 2862 } 2863 2864 /* 2865 * Copies a byte range from invp to outvp. Calls VOP_COPY_FILE_RANGE() 2866 * or vn_generic_copy_file_range() after rangelocking the byte ranges, 2867 * to do the actual copy. 2868 * vn_generic_copy_file_range() is factored out, so it can be called 2869 * from a VOP_COPY_FILE_RANGE() call as well, but handles vnodes from 2870 * different file systems. 2871 */ 2872 int 2873 vn_copy_file_range(struct vnode *invp, off_t *inoffp, struct vnode *outvp, 2874 off_t *outoffp, size_t *lenp, unsigned int flags, struct ucred *incred, 2875 struct ucred *outcred, struct thread *fsize_td) 2876 { 2877 int error; 2878 size_t len; 2879 uint64_t uval; 2880 2881 len = *lenp; 2882 *lenp = 0; /* For error returns. */ 2883 error = 0; 2884 2885 /* Do some sanity checks on the arguments. */ 2886 if (invp->v_type == VDIR || outvp->v_type == VDIR) 2887 error = EISDIR; 2888 else if (*inoffp < 0 || *outoffp < 0 || 2889 invp->v_type != VREG || outvp->v_type != VREG) 2890 error = EINVAL; 2891 if (error != 0) 2892 goto out; 2893 2894 /* Ensure offset + len does not wrap around. */ 2895 uval = *inoffp; 2896 uval += len; 2897 if (uval > INT64_MAX) 2898 len = INT64_MAX - *inoffp; 2899 uval = *outoffp; 2900 uval += len; 2901 if (uval > INT64_MAX) 2902 len = INT64_MAX - *outoffp; 2903 if (len == 0) 2904 goto out; 2905 2906 /* 2907 * If the two vnode are for the same file system, call 2908 * VOP_COPY_FILE_RANGE(), otherwise call vn_generic_copy_file_range() 2909 * which can handle copies across multiple file systems. 2910 */ 2911 *lenp = len; 2912 if (invp->v_mount == outvp->v_mount) 2913 error = VOP_COPY_FILE_RANGE(invp, inoffp, outvp, outoffp, 2914 lenp, flags, incred, outcred, fsize_td); 2915 else 2916 error = vn_generic_copy_file_range(invp, inoffp, outvp, 2917 outoffp, lenp, flags, incred, outcred, fsize_td); 2918 out: 2919 return (error); 2920 } 2921 2922 /* 2923 * Test len bytes of data starting at dat for all bytes == 0. 2924 * Return true if all bytes are zero, false otherwise. 2925 * Expects dat to be well aligned. 2926 */ 2927 static bool 2928 mem_iszero(void *dat, int len) 2929 { 2930 int i; 2931 const u_int *p; 2932 const char *cp; 2933 2934 for (p = dat; len > 0; len -= sizeof(*p), p++) { 2935 if (len >= sizeof(*p)) { 2936 if (*p != 0) 2937 return (false); 2938 } else { 2939 cp = (const char *)p; 2940 for (i = 0; i < len; i++, cp++) 2941 if (*cp != '\0') 2942 return (false); 2943 } 2944 } 2945 return (true); 2946 } 2947 2948 /* 2949 * Look for a hole in the output file and, if found, adjust *outoffp 2950 * and *xferp to skip past the hole. 2951 * *xferp is the entire hole length to be written and xfer2 is how many bytes 2952 * to be written as 0's upon return. 2953 */ 2954 static off_t 2955 vn_skip_hole(struct vnode *outvp, off_t xfer2, off_t *outoffp, off_t *xferp, 2956 off_t *dataoffp, off_t *holeoffp, struct ucred *cred) 2957 { 2958 int error; 2959 off_t delta; 2960 2961 if (*holeoffp == 0 || *holeoffp <= *outoffp) { 2962 *dataoffp = *outoffp; 2963 error = VOP_IOCTL(outvp, FIOSEEKDATA, dataoffp, 0, cred, 2964 curthread); 2965 if (error == 0) { 2966 *holeoffp = *dataoffp; 2967 error = VOP_IOCTL(outvp, FIOSEEKHOLE, holeoffp, 0, cred, 2968 curthread); 2969 } 2970 if (error != 0 || *holeoffp == *dataoffp) { 2971 /* 2972 * Since outvp is unlocked, it may be possible for 2973 * another thread to do a truncate(), lseek(), write() 2974 * creating a hole at startoff between the above 2975 * VOP_IOCTL() calls, if the other thread does not do 2976 * rangelocking. 2977 * If that happens, *holeoffp == *dataoffp and finding 2978 * the hole has failed, so disable vn_skip_hole(). 2979 */ 2980 *holeoffp = -1; /* Disable use of vn_skip_hole(). */ 2981 return (xfer2); 2982 } 2983 KASSERT(*dataoffp >= *outoffp, 2984 ("vn_skip_hole: dataoff=%jd < outoff=%jd", 2985 (intmax_t)*dataoffp, (intmax_t)*outoffp)); 2986 KASSERT(*holeoffp > *dataoffp, 2987 ("vn_skip_hole: holeoff=%jd <= dataoff=%jd", 2988 (intmax_t)*holeoffp, (intmax_t)*dataoffp)); 2989 } 2990 2991 /* 2992 * If there is a hole before the data starts, advance *outoffp and 2993 * *xferp past the hole. 2994 */ 2995 if (*dataoffp > *outoffp) { 2996 delta = *dataoffp - *outoffp; 2997 if (delta >= *xferp) { 2998 /* Entire *xferp is a hole. */ 2999 *outoffp += *xferp; 3000 *xferp = 0; 3001 return (0); 3002 } 3003 *xferp -= delta; 3004 *outoffp += delta; 3005 xfer2 = MIN(xfer2, *xferp); 3006 } 3007 3008 /* 3009 * If a hole starts before the end of this xfer2, reduce this xfer2 so 3010 * that the write ends at the start of the hole. 3011 * *holeoffp should always be greater than *outoffp, but for the 3012 * non-INVARIANTS case, check this to make sure xfer2 remains a sane 3013 * value. 3014 */ 3015 if (*holeoffp > *outoffp && *holeoffp < *outoffp + xfer2) 3016 xfer2 = *holeoffp - *outoffp; 3017 return (xfer2); 3018 } 3019 3020 /* 3021 * Write an xfer sized chunk to outvp in blksize blocks from dat. 3022 * dat is a maximum of blksize in length and can be written repeatedly in 3023 * the chunk. 3024 * If growfile == true, just grow the file via vn_truncate_locked() instead 3025 * of doing actual writes. 3026 * If checkhole == true, a hole is being punched, so skip over any hole 3027 * already in the output file. 3028 */ 3029 static int 3030 vn_write_outvp(struct vnode *outvp, char *dat, off_t outoff, off_t xfer, 3031 u_long blksize, bool growfile, bool checkhole, struct ucred *cred) 3032 { 3033 struct mount *mp; 3034 off_t dataoff, holeoff, xfer2; 3035 int error, lckf; 3036 3037 /* 3038 * Loop around doing writes of blksize until write has been completed. 3039 * Lock/unlock on each loop iteration so that a bwillwrite() can be 3040 * done for each iteration, since the xfer argument can be very 3041 * large if there is a large hole to punch in the output file. 3042 */ 3043 error = 0; 3044 holeoff = 0; 3045 do { 3046 xfer2 = MIN(xfer, blksize); 3047 if (checkhole) { 3048 /* 3049 * Punching a hole. Skip writing if there is 3050 * already a hole in the output file. 3051 */ 3052 xfer2 = vn_skip_hole(outvp, xfer2, &outoff, &xfer, 3053 &dataoff, &holeoff, cred); 3054 if (xfer == 0) 3055 break; 3056 if (holeoff < 0) 3057 checkhole = false; 3058 KASSERT(xfer2 > 0, ("vn_write_outvp: xfer2=%jd", 3059 (intmax_t)xfer2)); 3060 } 3061 bwillwrite(); 3062 mp = NULL; 3063 error = vn_start_write(outvp, &mp, V_WAIT); 3064 if (error != 0) 3065 break; 3066 if (growfile) { 3067 error = vn_lock(outvp, LK_EXCLUSIVE); 3068 if (error == 0) { 3069 error = vn_truncate_locked(outvp, outoff + xfer, 3070 false, cred); 3071 VOP_UNLOCK(outvp); 3072 } 3073 } else { 3074 if (MNT_SHARED_WRITES(mp)) 3075 lckf = LK_SHARED; 3076 else 3077 lckf = LK_EXCLUSIVE; 3078 error = vn_lock(outvp, lckf); 3079 if (error == 0) { 3080 error = vn_rdwr(UIO_WRITE, outvp, dat, xfer2, 3081 outoff, UIO_SYSSPACE, IO_NODELOCKED, 3082 curthread->td_ucred, cred, NULL, curthread); 3083 outoff += xfer2; 3084 xfer -= xfer2; 3085 VOP_UNLOCK(outvp); 3086 } 3087 } 3088 if (mp != NULL) 3089 vn_finished_write(mp); 3090 } while (!growfile && xfer > 0 && error == 0); 3091 return (error); 3092 } 3093 3094 /* 3095 * Copy a byte range of one file to another. This function can handle the 3096 * case where invp and outvp are on different file systems. 3097 * It can also be called by a VOP_COPY_FILE_RANGE() to do the work, if there 3098 * is no better file system specific way to do it. 3099 */ 3100 int 3101 vn_generic_copy_file_range(struct vnode *invp, off_t *inoffp, 3102 struct vnode *outvp, off_t *outoffp, size_t *lenp, unsigned int flags, 3103 struct ucred *incred, struct ucred *outcred, struct thread *fsize_td) 3104 { 3105 struct vattr va, inva; 3106 struct mount *mp; 3107 struct uio io; 3108 off_t startoff, endoff, xfer, xfer2; 3109 u_long blksize; 3110 int error, interrupted; 3111 bool cantseek, readzeros, eof, lastblock, holetoeof; 3112 ssize_t aresid; 3113 size_t copylen, len, rem, savlen; 3114 char *dat; 3115 long holein, holeout; 3116 3117 holein = holeout = 0; 3118 savlen = len = *lenp; 3119 error = 0; 3120 interrupted = 0; 3121 dat = NULL; 3122 3123 error = vn_lock(invp, LK_SHARED); 3124 if (error != 0) 3125 goto out; 3126 if (VOP_PATHCONF(invp, _PC_MIN_HOLE_SIZE, &holein) != 0) 3127 holein = 0; 3128 if (holein > 0) 3129 error = VOP_GETATTR(invp, &inva, incred); 3130 VOP_UNLOCK(invp); 3131 if (error != 0) 3132 goto out; 3133 3134 mp = NULL; 3135 error = vn_start_write(outvp, &mp, V_WAIT); 3136 if (error == 0) 3137 error = vn_lock(outvp, LK_EXCLUSIVE); 3138 if (error == 0) { 3139 /* 3140 * If fsize_td != NULL, do a vn_rlimit_fsize() call, 3141 * now that outvp is locked. 3142 */ 3143 if (fsize_td != NULL) { 3144 io.uio_offset = *outoffp; 3145 io.uio_resid = len; 3146 error = vn_rlimit_fsize(outvp, &io, fsize_td); 3147 if (error != 0) 3148 error = EFBIG; 3149 } 3150 if (VOP_PATHCONF(outvp, _PC_MIN_HOLE_SIZE, &holeout) != 0) 3151 holeout = 0; 3152 /* 3153 * Holes that are past EOF do not need to be written as a block 3154 * of zero bytes. So, truncate the output file as far as 3155 * possible and then use va.va_size to decide if writing 0 3156 * bytes is necessary in the loop below. 3157 */ 3158 if (error == 0) 3159 error = VOP_GETATTR(outvp, &va, outcred); 3160 if (error == 0 && va.va_size > *outoffp && va.va_size <= 3161 *outoffp + len) { 3162 #ifdef MAC 3163 error = mac_vnode_check_write(curthread->td_ucred, 3164 outcred, outvp); 3165 if (error == 0) 3166 #endif 3167 error = vn_truncate_locked(outvp, *outoffp, 3168 false, outcred); 3169 if (error == 0) 3170 va.va_size = *outoffp; 3171 } 3172 VOP_UNLOCK(outvp); 3173 } 3174 if (mp != NULL) 3175 vn_finished_write(mp); 3176 if (error != 0) 3177 goto out; 3178 3179 /* 3180 * Set the blksize to the larger of the hole sizes for invp and outvp. 3181 * If hole sizes aren't available, set the blksize to the larger 3182 * f_iosize of invp and outvp. 3183 * This code expects the hole sizes and f_iosizes to be powers of 2. 3184 * This value is clipped at 4Kbytes and 1Mbyte. 3185 */ 3186 blksize = MAX(holein, holeout); 3187 3188 /* Clip len to end at an exact multiple of hole size. */ 3189 if (blksize > 1) { 3190 rem = *inoffp % blksize; 3191 if (rem > 0) 3192 rem = blksize - rem; 3193 if (len > rem && len - rem > blksize) 3194 len = savlen = rounddown(len - rem, blksize) + rem; 3195 } 3196 3197 if (blksize <= 1) 3198 blksize = MAX(invp->v_mount->mnt_stat.f_iosize, 3199 outvp->v_mount->mnt_stat.f_iosize); 3200 if (blksize < 4096) 3201 blksize = 4096; 3202 else if (blksize > 1024 * 1024) 3203 blksize = 1024 * 1024; 3204 dat = malloc(blksize, M_TEMP, M_WAITOK); 3205 3206 /* 3207 * If VOP_IOCTL(FIOSEEKHOLE) works for invp, use it and FIOSEEKDATA 3208 * to find holes. Otherwise, just scan the read block for all 0s 3209 * in the inner loop where the data copying is done. 3210 * Note that some file systems such as NFSv3, NFSv4.0 and NFSv4.1 may 3211 * support holes on the server, but do not support FIOSEEKHOLE. 3212 */ 3213 holetoeof = eof = false; 3214 while (len > 0 && error == 0 && !eof && interrupted == 0) { 3215 endoff = 0; /* To shut up compilers. */ 3216 cantseek = true; 3217 startoff = *inoffp; 3218 copylen = len; 3219 3220 /* 3221 * Find the next data area. If there is just a hole to EOF, 3222 * FIOSEEKDATA should fail with ENXIO. 3223 * (I do not know if any file system will report a hole to 3224 * EOF via FIOSEEKHOLE, but I am pretty sure FIOSEEKDATA 3225 * will fail for those file systems.) 3226 * 3227 * For input files that don't support FIOSEEKDATA/FIOSEEKHOLE, 3228 * the code just falls through to the inner copy loop. 3229 */ 3230 error = EINVAL; 3231 if (holein > 0) { 3232 error = VOP_IOCTL(invp, FIOSEEKDATA, &startoff, 0, 3233 incred, curthread); 3234 if (error == ENXIO) { 3235 startoff = endoff = inva.va_size; 3236 eof = holetoeof = true; 3237 error = 0; 3238 } 3239 } 3240 if (error == 0 && !holetoeof) { 3241 endoff = startoff; 3242 error = VOP_IOCTL(invp, FIOSEEKHOLE, &endoff, 0, 3243 incred, curthread); 3244 /* 3245 * Since invp is unlocked, it may be possible for 3246 * another thread to do a truncate(), lseek(), write() 3247 * creating a hole at startoff between the above 3248 * VOP_IOCTL() calls, if the other thread does not do 3249 * rangelocking. 3250 * If that happens, startoff == endoff and finding 3251 * the hole has failed, so set an error. 3252 */ 3253 if (error == 0 && startoff == endoff) 3254 error = EINVAL; /* Any error. Reset to 0. */ 3255 } 3256 if (error == 0) { 3257 if (startoff > *inoffp) { 3258 /* Found hole before data block. */ 3259 xfer = MIN(startoff - *inoffp, len); 3260 if (*outoffp < va.va_size) { 3261 /* Must write 0s to punch hole. */ 3262 xfer2 = MIN(va.va_size - *outoffp, 3263 xfer); 3264 memset(dat, 0, MIN(xfer2, blksize)); 3265 error = vn_write_outvp(outvp, dat, 3266 *outoffp, xfer2, blksize, false, 3267 holeout > 0, outcred); 3268 } 3269 3270 if (error == 0 && *outoffp + xfer > 3271 va.va_size && (xfer == len || holetoeof)) { 3272 /* Grow output file (hole at end). */ 3273 error = vn_write_outvp(outvp, dat, 3274 *outoffp, xfer, blksize, true, 3275 false, outcred); 3276 } 3277 if (error == 0) { 3278 *inoffp += xfer; 3279 *outoffp += xfer; 3280 len -= xfer; 3281 if (len < savlen) 3282 interrupted = sig_intr(); 3283 } 3284 } 3285 copylen = MIN(len, endoff - startoff); 3286 cantseek = false; 3287 } else { 3288 cantseek = true; 3289 startoff = *inoffp; 3290 copylen = len; 3291 error = 0; 3292 } 3293 3294 xfer = blksize; 3295 if (cantseek) { 3296 /* 3297 * Set first xfer to end at a block boundary, so that 3298 * holes are more likely detected in the loop below via 3299 * the for all bytes 0 method. 3300 */ 3301 xfer -= (*inoffp % blksize); 3302 } 3303 /* Loop copying the data block. */ 3304 while (copylen > 0 && error == 0 && !eof && interrupted == 0) { 3305 if (copylen < xfer) 3306 xfer = copylen; 3307 error = vn_lock(invp, LK_SHARED); 3308 if (error != 0) 3309 goto out; 3310 error = vn_rdwr(UIO_READ, invp, dat, xfer, 3311 startoff, UIO_SYSSPACE, IO_NODELOCKED, 3312 curthread->td_ucred, incred, &aresid, 3313 curthread); 3314 VOP_UNLOCK(invp); 3315 lastblock = false; 3316 if (error == 0 && aresid > 0) { 3317 /* Stop the copy at EOF on the input file. */ 3318 xfer -= aresid; 3319 eof = true; 3320 lastblock = true; 3321 } 3322 if (error == 0) { 3323 /* 3324 * Skip the write for holes past the initial EOF 3325 * of the output file, unless this is the last 3326 * write of the output file at EOF. 3327 */ 3328 readzeros = cantseek ? mem_iszero(dat, xfer) : 3329 false; 3330 if (xfer == len) 3331 lastblock = true; 3332 if (!cantseek || *outoffp < va.va_size || 3333 lastblock || !readzeros) 3334 error = vn_write_outvp(outvp, dat, 3335 *outoffp, xfer, blksize, 3336 readzeros && lastblock && 3337 *outoffp >= va.va_size, false, 3338 outcred); 3339 if (error == 0) { 3340 *inoffp += xfer; 3341 startoff += xfer; 3342 *outoffp += xfer; 3343 copylen -= xfer; 3344 len -= xfer; 3345 if (len < savlen) 3346 interrupted = sig_intr(); 3347 } 3348 } 3349 xfer = blksize; 3350 } 3351 } 3352 out: 3353 *lenp = savlen - len; 3354 free(dat, M_TEMP); 3355 return (error); 3356 } 3357 3358 static int 3359 vn_fallocate(struct file *fp, off_t offset, off_t len, struct thread *td) 3360 { 3361 struct mount *mp; 3362 struct vnode *vp; 3363 off_t olen, ooffset; 3364 int error; 3365 #ifdef AUDIT 3366 int audited_vnode1 = 0; 3367 #endif 3368 3369 vp = fp->f_vnode; 3370 if (vp->v_type != VREG) 3371 return (ENODEV); 3372 3373 /* Allocating blocks may take a long time, so iterate. */ 3374 for (;;) { 3375 olen = len; 3376 ooffset = offset; 3377 3378 bwillwrite(); 3379 mp = NULL; 3380 error = vn_start_write(vp, &mp, V_WAIT | PCATCH); 3381 if (error != 0) 3382 break; 3383 error = vn_lock(vp, LK_EXCLUSIVE); 3384 if (error != 0) { 3385 vn_finished_write(mp); 3386 break; 3387 } 3388 #ifdef AUDIT 3389 if (!audited_vnode1) { 3390 AUDIT_ARG_VNODE1(vp); 3391 audited_vnode1 = 1; 3392 } 3393 #endif 3394 #ifdef MAC 3395 error = mac_vnode_check_write(td->td_ucred, fp->f_cred, vp); 3396 if (error == 0) 3397 #endif 3398 error = VOP_ALLOCATE(vp, &offset, &len); 3399 VOP_UNLOCK(vp); 3400 vn_finished_write(mp); 3401 3402 if (olen + ooffset != offset + len) { 3403 panic("offset + len changed from %jx/%jx to %jx/%jx", 3404 ooffset, olen, offset, len); 3405 } 3406 if (error != 0 || len == 0) 3407 break; 3408 KASSERT(olen > len, ("Iteration did not make progress?")); 3409 maybe_yield(); 3410 } 3411 3412 return (error); 3413 } 3414 3415 static u_long vn_lock_pair_pause_cnt; 3416 SYSCTL_ULONG(_debug, OID_AUTO, vn_lock_pair_pause, CTLFLAG_RD, 3417 &vn_lock_pair_pause_cnt, 0, 3418 "Count of vn_lock_pair deadlocks"); 3419 3420 u_int vn_lock_pair_pause_max; 3421 SYSCTL_UINT(_debug, OID_AUTO, vn_lock_pair_pause_max, CTLFLAG_RW, 3422 &vn_lock_pair_pause_max, 0, 3423 "Max ticks for vn_lock_pair deadlock avoidance sleep"); 3424 3425 static void 3426 vn_lock_pair_pause(const char *wmesg) 3427 { 3428 atomic_add_long(&vn_lock_pair_pause_cnt, 1); 3429 pause(wmesg, prng32_bounded(vn_lock_pair_pause_max)); 3430 } 3431 3432 /* 3433 * Lock pair of vnodes vp1, vp2, avoiding lock order reversal. 3434 * vp1_locked indicates whether vp1 is exclusively locked; if not, vp1 3435 * must be unlocked. Same for vp2 and vp2_locked. One of the vnodes 3436 * can be NULL. 3437 * 3438 * The function returns with both vnodes exclusively locked, and 3439 * guarantees that it does not create lock order reversal with other 3440 * threads during its execution. Both vnodes could be unlocked 3441 * temporary (and reclaimed). 3442 */ 3443 void 3444 vn_lock_pair(struct vnode *vp1, bool vp1_locked, struct vnode *vp2, 3445 bool vp2_locked) 3446 { 3447 int error; 3448 3449 if (vp1 == NULL && vp2 == NULL) 3450 return; 3451 if (vp1 != NULL) { 3452 if (vp1_locked) 3453 ASSERT_VOP_ELOCKED(vp1, "vp1"); 3454 else 3455 ASSERT_VOP_UNLOCKED(vp1, "vp1"); 3456 } else { 3457 vp1_locked = true; 3458 } 3459 if (vp2 != NULL) { 3460 if (vp2_locked) 3461 ASSERT_VOP_ELOCKED(vp2, "vp2"); 3462 else 3463 ASSERT_VOP_UNLOCKED(vp2, "vp2"); 3464 } else { 3465 vp2_locked = true; 3466 } 3467 if (!vp1_locked && !vp2_locked) { 3468 vn_lock(vp1, LK_EXCLUSIVE | LK_RETRY); 3469 vp1_locked = true; 3470 } 3471 3472 for (;;) { 3473 if (vp1_locked && vp2_locked) 3474 break; 3475 if (vp1_locked && vp2 != NULL) { 3476 if (vp1 != NULL) { 3477 error = VOP_LOCK1(vp2, LK_EXCLUSIVE | LK_NOWAIT, 3478 __FILE__, __LINE__); 3479 if (error == 0) 3480 break; 3481 VOP_UNLOCK(vp1); 3482 vp1_locked = false; 3483 vn_lock_pair_pause("vlp1"); 3484 } 3485 vn_lock(vp2, LK_EXCLUSIVE | LK_RETRY); 3486 vp2_locked = true; 3487 } 3488 if (vp2_locked && vp1 != NULL) { 3489 if (vp2 != NULL) { 3490 error = VOP_LOCK1(vp1, LK_EXCLUSIVE | LK_NOWAIT, 3491 __FILE__, __LINE__); 3492 if (error == 0) 3493 break; 3494 VOP_UNLOCK(vp2); 3495 vp2_locked = false; 3496 vn_lock_pair_pause("vlp2"); 3497 } 3498 vn_lock(vp1, LK_EXCLUSIVE | LK_RETRY); 3499 vp1_locked = true; 3500 } 3501 } 3502 if (vp1 != NULL) 3503 ASSERT_VOP_ELOCKED(vp1, "vp1 ret"); 3504 if (vp2 != NULL) 3505 ASSERT_VOP_ELOCKED(vp2, "vp2 ret"); 3506 } 3507