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