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