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